Drought conditions ease for North Texas

July 4th, 2009 Sean Toner No comments

Despite the warmer than normal conditions the past few weeks across north Texas, the immediate area remains mostly drought free. This is thanks in part to a wetter than normal mid-spring and a particularly rainy June 10-11. At this time nearly half of north Texas is drought free, however other areas range from a D1 all the way to D4 drought classification.

Agriculture is still suffering as soil moisture is still fairly low for the entire region, plus warmer than normal temps the past few weeks are causing substantial evaporation rates. Thankfully the region’s water reservoirs are mostly above 90% conservation, meaning there is plenty of water for the region to make it through summer without mandatory water restrictions. An amazing fact that I did not know, afternoon temperatures of 100 degrees can evaporate just as much water out of Lake Lewisville daily as all of Collin County uses in the same time period! That is 250 million gallons each, meaning possibly half a billion gallons are removed from Lake Lewisville every day, wow!

Long term climate forecasts show a fairly typical or possibly drier than normal Summer for north Texas. Anytime from maybe mid July through end of August at least is forecast to be very hot and mostly rain free. There is still a possibility of rain from now through mid July, including a cold front that will affect the area Monday-ish(7/6/09).

Areas west of Fort Worth in Palo Pinto, Stephens and Young counties are still in D1 drought designation, which simply means ‘Abnormally Dry’. Large areas of central Texas (to our south, areas around Austin) however are in a D4 classification which means ‘Exceptional Drought’, the most severe classification. Exceptional droughts are the type that have a return period of a half-century! For comparison, if you remember the extreme drought talks revolving around south Tennessee and Atlanta, Georgia running out of water last year, I only noticed them listed under a D3 classification.

Map showing the current drought classifications across the country. Note that Florida is now out of official drought classifications due to a rainy May and June. Good thing too, central Florida has been in either D1 or D2 status for a few years now.

63009-droughtmonitor

Detailed information released by the National Weather Service regarding drought information in North Texas:

DROUGHT INFORMATION STATEMENT
NATIONAL WEATHER SERVICE FORT WORTH TX
1110 PM CDT THU JUL 2 2009

...CENTRAL TEXAS DROUGHT RE-INTENSIFIES...

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SYNOPSIS...

MAY AND JUNE WERE AMONG THE DRIEST ON RECORD IN PORTIONS OF CENTRAL
TEXAS...WHERE DROUGHT HAS BEEN LARGELY UNINTERRUPTED SINCE THE
SUMMER OF 2008. EXTREME DROUGHT (D3) HAS BEEN EXPANDED...AND
EXCEPTIONAL DROUGHT (D4) HAS RETURNED TO MILAM COUNTY. THE MOST
INTENSE CATEGORY...EXCEPTIONAL DROUGHT IS RESERVED FOR EVENTS WITH A
RETURN PERIOD OF A HALF CENTURY.

THE RECENT AREA OF CONCERN IN WESTERN NORTH TEXAS CONTINUES TO
IMPROVE...ALTHOUGH MODERATE DROUGHT (D1) REMAINS ACROSS YOUNG...
STEPHENS...AND PALO PINTO COUNTIES. THANKS IN PART TO ADEQUATE
SPRING RAINFALL (AND A DELUGE THE SECOND WEEK OF JUNE)...NEARLY HALF
OF THE NWS FORT WORTH AREA OF RESPONSIBILITY CURRENTLY HAS NO
DROUGHT DESIGNATION.

UNFORTUNATELY FOR THOSE AREAS STILL IN DROUGHT...NO SIGNIFICANT
RELIEF IS ANTICIPATED THIS SUMMER...AND THE CENTRAL TEXAS DROUGHT IS
LIKELY TO PERSIST. FORTUNATELY...NEARLY EVERY NORTH TEXAS LAKE IS
ABOVE 80 PERCENT CONSERVATION...WITH MOST OVER 90 PERCENT. EVEN
CENTRAL TEXAS RESERVOIRS ARE GENERALLY IN GOOD SHAPE...DESPITE
CONSIDERABLE PRECIPITATION DEFICITS.

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SUMMARY OF IMPACTS...

AGRICULTURAL IMPACTS

BY THE END OF JUNE...LESS THAN A QUARTER OF NORTH TEXAS FARMLAND HAD
ADEQUATE SOIL MOISTURE. THE WORST IMPACTS CONTINUE TO BE IN CENTRAL
TEXAS...WHERE THE CORN CROP IS STRUGGLING WITH EXTRAORDINARY HEAT.
ALTHOUGH GENERALLY DROUGHT RESISTANT...SORGHUM IS ALSO STRESSED.
SUPPLEMENTAL FEEDING CONTINUES IN AREAS WHERE FORAGE IS DEPLETED OR
OTHERWISE INADEQUATE.

FIRE DANGER

THE ABUNDANT EARLY SPRING RAINS GOT THE GROWING SEASON OFF TO A
BOOMING START...BUT NEARLY ALL OF NORTH TEXAS SAW BELOW NORMAL
RAINFALL DURING MAY AND JUNE. THE TURN OF FORTUNE WAS PARTICULARLY
NOTICEABLE IN CENTRAL TEXAS. MANY AREAS BETWEEN I-35 AND I-45
RECEIVED LESS THAN AN INCH OF RAIN DURING THE LAST TWO MONTHS
COMBINED.

THE DRY VEGETATION HAS BECOME A CONCERN AS INDEPENDENCE DAY
FESTIVITIES APPROACH. RESIDENTS ARE URGED TO BE VIGILANT ABOUT FIRE
USAGE. ADHERE TO LOCAL BURN BANS AND AERIAL FIREWORKS RESTRICTIONS.
EVEN WITH ELEVATED HUMIDITY AND LIGHT WINDS...WILDFIRES CAN QUICKLY
START WHERE SUMMER VEGETATION IS DORMANT. SEVERAL NEW BURN BANS WERE
ENACTED DURING JUNE...BRINGING THE TOTAL TO 14 IN THE NWS FORT WORTH
AREA OF RESPONSIBILITY. MOST OF THE NEW ADDITIONS WERE IN CENTRAL
TEXAS.

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CLIMATE SUMMARY...

ON JUNE 10 AND 11...TORRENTIAL RAINS FELL IN NORTH CENTRAL TEXAS.
WIDESPREAD TOTALS OF 7 TO 8 INCHES WERE RECORDED IN CENTRAL DALLAS.
HOWEVER...MUCH OF NORTH TEXAS MISSED OUT ON THE RAIN EVENT...AND
STRUGGLED THROUGH A SECOND STRAIGHT MONTH WITH BELOW NORMAL
PRECIPITATION.

CENTRAL TEXAS WAS PARTICULARLY HARD HIT...WITH MANY LOCATIONS
RECEIVING UNDER AN INCH IN THE LAST 60 DAYS. WACO REGIONAL AIRPORT
WENT 33 CONSECUTIVE DAYS WITHOUT MEASURABLE RAINFALL...BEFORE THE
STREAK WAS BROKEN ON JUNE 30. THE COOPERATIVE OBSERVER IN THORNTON
(LIMESTONE COUNTY) RECORDED 10.42 INCHES OF RAIN IN APRIL...BUT ONLY
0.05 INCHES IN JUNE. WITHIN THE EXTREME AND EXCEPTIONAL DROUGHT
AREAS OF CENTRAL TEXAS...SOME LOCATIONS HAVE AMASSED DEFICITS OF 20
INCHES SINCE LAST SUMMER.

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PRECIPITATION/TEMPERATURE OUTLOOK...

RIDGING ALOFT IS PROJECTED TO CONTINUE DOMINATING THE LONE STAR
STATE DURING THE FIRST HALF OF JULY. AS A RESULT...THE 6-10 DAY AND
8-14 DAY OUTLOOKS FROM THE CLIMATE PREDICTION CENTER (FOR EARLY TO
MID JULY) HAVE MAINTAINED THE LIKELIHOOD FOR PERSISTENT ABOVE NORMAL
TEMPERATURES AND BELOW NORMAL PRECIPITATION. BOTH WOULD ASSURE
FURTHER EVAPORATION...TAXING VEGETATION AND AREA RESERVOIRS. FADING
SOIL MOISTURE IS A POSITIVE FEEDBACK IN THE PROCESS...LEADING TO
ADDITIONAL WARMING.

STRONG PRECIPITATION SIGNALS ARE RARELY SEEN DURING THE SUMMER
MONTHS...AND NONE ARE PRESENT BEYOND THE NEXT COUPLE OF WEEKS.
THUS...IT IS UNLIKELY THAT THE WELL ENTRENCHED CENTRAL TEXAS DROUGHT
WILL ABATE BEFORE AUTUMN.

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HYDROLOGIC SUMMARY AND OUTLOOK...

THE RESERVOIR GAINS THAT FOLLOWED THE HEAVY RAINS OF EARLY JUNE WERE
LARGELY ERASED BY THE HOT WEATHER DURING THE LAST HALF OF THE MONTH.
ON THE HOTTEST OF DAYS...EVAPORATION ALONE CAN SKIM A HALF-INCH FROM
THE SURFACE OF A LAKE. FROM LAKE LEWISVILLE...THAT EQUATES TO A
QUARTER OF A BILLION GALLONS. THIS IS EQUIVALENT TO THE TOTAL WATER
USAGE IN COLLIN COUNTY ON A TYPICAL SUMMER DAY. NEEDLESS TO SAY...A
CONTINUATION OF HOT WEATHER WILL ALLOW BOTH USAGE AND EVAPORATION TO
TAKE THEIR TOLL ON NORTH TEXAS WATER RESOURCES. THANKFULLY...MOST
RESERVOIRS WERE ABOVE 90 PERCENT CONSERVATION AT THE BEGINNING OF
JULY.

                               RESERVOIR DATA - JULY 2, 2009

                         NORMAL     POOL     DEFICIT/    PERCENT OF
                          POOL     HEIGHT    SURPLUS    CONSERVATION

RED RIVER BASIN
  LAKE TEXOMA             619.0    618.92     -0.08          99
  PAY MAYSE LAKE          451.0    451.27     +0.27         101
  JIM CHAPMAN LAKE        440.0    439.42     -0.58          96

TRINITY RIVER BASIN
  LAKE BRIDGEPORT         836.0    827.46     -8.54          73
  EAGLE MOUNTAIN LAKE     649.0    645.15     -3.85          83
  LAKE WORTH              594.0    591.73     -2.27          80
  LAKE BENBROOK           694.0    692.58     -1.42          93
  LAKE RAY ROBERTS        632.5    632.50      0.00         100
  LAKE LEWISVILLE         522.0    521.67     -0.33          98
  LAKE GRAPEVINE          535.0    532.82     -2.18          90
  LAKE LAVON              492.0    491.31     -0.69          97
  LAKE RAY HUBBARD        435.5    435.34     -0.16          99
  JOE POOL LAKE           522.0    521.48     -0.52          97
  BARDWELL LAKE           421.0    419.78     -1.22          92
  NAVARRO MILLS LAKE      424.5    423.82     -0.68          94
  CEDAR CREEK RESERVOIR   322.0    321.63     -0.37          98
  RICHLAND CHAMBERS       315.0    311.83     -3.17          88

BRAZOS RIVER BASIN
  POSSUM KINGDOM LAKE    1000.0    996.18     -3.82          86
  PROCTOR LAKE           1162.0   1156.67     -5.33          57
  BELTON LAKE             594.0    591.22     -2.78          91
  STILLHOUSE HOLLOW       622.0    620.15     -1.85          95
  LAKE GRANBURY           693.0    690.59     -2.41          86
  LAKE WHITNEY            533.0    523.33     -9.67          21
  AQUILLA LAKE            537.5    536.46     -1.04          90
  WACO LAKE               462.0    461.68     -0.32          99
  LAKE LIMESTONE          363.0    361.74     -1.26          92

IN GENERAL...WATER SUPPLIES ARE ADEQUATE TO HANDLE SUMMER DEMAND.
NONETHELESS...MANY JURISDICTIONS HAVE MAINTAINED CALLS FOR VOLUNTARY
CONSERVATION. EVEN IF FORMAL WATER RESTRICTIONS ARE NOT CURRENTLY IN
PLACE FOR YOUR AREA...RESIDENTS ARE URGED TO BE SENSIBLE ABOUT WATER
USAGE. AVOID WATERING BETWEEN 10 AM AND 6 PM...WHEN EVAPORATION
LIMITS ITS EFFECTIVENESS.

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NEXT ISSUANCE DATE...

THE NEXT DROUGHT INFORMATION STATEMENT WILL BE ISSUED IN LATE JULY
OR EARLY AUGUST.

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&&

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RELATED WEB SITES...

NWS FORT WORTH DROUGHT PAGE - WEATHER.GOV/FORTWORTH/DROUGHT.HTML
NATIONAL INTEGRATED DROUGHT INFORMATION SYSTEM - DROUGHT.GOV
CLIMATE PREDICTION CENTER - WWW.CPC.NCEP.NOAA.GOV

NATIONAL DROUGHT MITIGATION CENTER - DROUGHT.UNL.EDU
U.S. DROUGHT MONITOR - DROUGHT.UNL.EDU/DM
DROUGHT IMPACT REPORTER - DROUGHTREPORTER.UNL.EDU

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ACKNOWLEDGEMENTS...

THE U.S. DROUGHT MONITOR FACILITATES CONTINUOUS DISCUSSION AMONG
NUMEROUS AGENCIES...ACADEMIA...AND OTHER LOCAL INTERESTS. THE
EXPERTISE OF ITS MEMBERS HAS BEEN INVALUABLE IN DEVELOPING DROUGHT
PRODUCTS AND SERVICES FOR OUR CUSTOMERS AND PARTNERS.

THE DROUGHT IMPACT REPORTER (MAINTAINED BY THE NATIONAL DROUGHT
MITIGATION CENTER) HAS ALLOWED VARIOUS IMPACTS TO BE COMPILED WITHIN
ONE CLEARING HOUSE. THESE IMPACTS INCLUDE AGRICULTURAL ISSUES...
HYDROLOGIC DEFICITS...FIRE DANGER...AND OTHER SOCIAL AND ECONOMIC
CONSEQUENCES. A SUMMARY OF THE SUBMITTED IMPACTS IS INCLUDED IN EACH
DROUGHT INFORMATION STATEMENT.

THE TEXAS DEPARTMENT OF AGRICULTURE AND THE TEXAS AGRILIFE EXTENSION
SERVICE PROVIDE ROUTINE ASSESSMENTS OF CROP AND PASTURE CONDITIONS
TO THE NATIONAL AGRICULTURAL STATISTICS SERVICE (NASS)...PART OF THE
UNITED STATES DEPARTMENT OF AGRICULTURE (USDA). THE PERIODIC
STATEWIDE SUMMARIES THAT RESULT ARE USED AS A PRIMARY SOURCE FOR THE
AGRICULTURAL IMPACTS SECTION.

THE TEXAS FOREST SERVICE (TFS) CONTINUALLY MONITORS VEGETATION
CONDITIONS AND WILDFIRE POTENTIAL. THE STATE AGENCY ALSO MAINTAINS A
CURRENT LIST OF COUNTYWIDE BURN BANS.

OUTLOOKS OF TEMPERATURE AND PRECIPITATION ARE SUMMARIZED FROM A
VARIETY OF PRODUCTS CREATED BY THE CLIMATE PREDICTION CENTER (CPC).
CPC IS A NATIONAL WEATHER SERVICE (NWS) ENTITY WITHIN THE NATIONAL
CENTERS FOR ENVIRONMENTAL PREDICTION (NCEP).

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QUESTIONS OR COMMENTS...

FOR ADDITIONAL INFORMATION OR TO PROVIDE FEEDBACK ON OUR DROUGHT
PRODUCTS AND SERVICES...PLEASE CONTACT...

NATIONAL WEATHER SERVICE
WEATHER FORECAST OFFICE
3401 NORTHERN CROSS BLVD.
FORT WORTH, TX 76137

PHONE: (817) 429-2631
E-MAIL: SR-FWD.WEBMASTER@NOAA.GOV

-- Weather When Posted --

Location: Frisco, TX

Temperature: 89.6°F, Humidity: 34%

July 4 weather outlook for Tampa Bay

July 2nd, 2009 Sean Toner No comments

Hey everyone, heres a brief weather update for the holiday weekend.

070309-tpa-graphicast1
Friday looks to bring more of the same as there has been the last few days. Southwest wind flow will carry thunderstorms inland from the gulf creating heavy rain and localized flooding conditions. Rain chances are fairly elevated, sitting at 50%. High temps of 88 degrees are a tad lower than normal, likely due to increased cloud cover and heavy rains. As is typical with Florida afternoon storms, an isolated severe threat is possible, but not moreso than usual.

070409-tpa-graphicast1
Saturday night thru Wednesday will return back to a typical Florida seabreeze pattern. The seabreeze will hug closer to the gulf coast from Tampa Bay south, and push further inland in areas north of Tampa. With this pattern it is not unusual to see an early afternoon thunderstorm over central Pinellas county anywhere from noon to 3pm, and lines of storms forming more inland anytime after that. These storms do occasionally develop outflow boundaries that push back out twards the gulf and generate more storms. This is nothing new for Florida afternoon thunderstorms though, but I am sure everyone knows about the whole ‘rapidly changing weather conditions, lightning can strike 10 miles away’ speech. Heat index values in areas that do not receive rain cooled air can reach up to 110 degrees, so keep well hydrated and keep sunscreen around.

Have a great 4th everyone!

-- Weather When Posted --

Location: Treasure Island, FL

Temperature: 77°F, Humidity: 90%

July 4 weather outlook for North Texas

July 2nd, 2009 Sean Toner No comments

Hey folks, I know I haven’t been up on the emailing as much the last week or so, been just a tad busy during my off hours though. Here is a weather outlook for the next few days…

070309-graphicast1
Friday will be just as hot as Thursday, with high temps just over 100 degrees. Dew points will be about the same as well, sitting around 60 to 65 degrees. This creates heat index values around 105F, just shy of heat advisory criteria. Air pollution watch level Orange is issued for Friday, just like every other day this week. Skies will be clear and winds from the south at 5-10mph. Nothing too special for Friday, other than very bright clear skies and hot.

070409-graphicast1
Saturday will be marginally cooler than Friday, with high temps around 100 and heat index values around 105. Mostly clear skies, air pollution watch level orange, and southwest winds 10 to 15mph. If your spending any amount of time outside Saturday, remember the sunblock and water. No rain is forecast so aside from the heat, Saturday will be an excellent outdoor day.

A cold front is expected to push through the area either Sunday or Monday. Computer models are having a hard time pinpointing the time when it will actually move through, but it will happen. At this time, rain chances can occur around Frisco anytime from maybe Sunday midday through Monday night. There is not alot of confidence in the timing of this however, so this is subject to change. Rain chances are only at 20% at this time and no severe weather is anticipated. Temperatures on Monday will be cooler due to this front, with high temps only expected to reach 90 degrees. Temps bounce back quickly on Tuesday and beyond though as temps are forecast to reach or exceed 95 degrees.

Have a happy 4th everyone!

-- Weather When Posted --

Location: Frisco, TX

Temperature: 96.8°F, Humidity: 30%

Tornado damage confirmed in Carrollwood Village!

June 30th, 2009 Sean Toner No comments

Looks like the NWS is confirming tornado damage in Carrollwood Village from a tornado earlier this afternoon. Usually it takes the weather service a day or two to perform damage surveys so this is extremely fast. They rated this as an eF-0 tornado which toppled pine trees and telephone poles in Carrollwood Village along Golf Crest Circle. The trees that fell hit a house and broke some shingles. No other damage reports have come in at this time.

-- Weather When Posted --

Location: Carrollwood Village-Tampa,FL

Temperature: 78.8°F, Humidity: 90%

Threat has ended – Tornado warning for Hillsborough County!

June 30th, 2009 Sean Toner No comments

The tornado warning has ended for Hillsborough County. The storm that produced the warning weakened and rotation completely stopped. The rotation spun up over Carrollwood Village at Fletcher & Dale Mabry, continued east twards I-275 and Fowler, and occluded near Busch and 30th.

No tornado or wind damage reports have come in at this time, but if any do then I will post updates. Below is screenshot from 3:18pm of reflectivity (left) and velocity (right).

063009-1518-tornadowarning.PNG

-- Weather When Posted --

Location: Tampa, FL

Temperature: 82.4°F, Humidity: 78%

Tornado warning for Hillsborough County!

June 30th, 2009 Sean Toner No comments

The center of circulation is over the Lake Magdalene area, moving ESE! This will affect Temple Terrace as well!

063009-1518-tornadowarning

The National Weather Service in Ruskin has issued a

* Tornado Warning for…
northwestern Hillsborough County in Florida.

* Until 345 PM EDT

* at 309 PM EDT…National Weather Service Doppler radar indicated a
tornado near Carrollwood…or 6 miles southwest of Lutz…moving
southeast at 10 mph.

* The tornado will be near…
Carrollwood.
Tampa International Airport.
Temple Terrace.

Precautionary/preparedness actions…

If you are in the path of the tornado go to a small interior room in
a strong and well constructed building. Cars and Mobile homes are not
safe! If no shelter is available…lie flat in a ditch or culvert and
cover your head with your hands.

To report severe weather to the National Weather Service please call
813-645-2323.

-- Weather When Posted --

Location: Tampa, FL

Temperature: 80.6°F, Humidity: 88%

Today weather forecast

June 30th, 2009 Sean Toner No comments

Hey everyone, sorry I have not had a chance to send out any updates the last two or so days. This will be brief as well… Looks like today we continue to have a chance for thunderstorms, though highest risk is in the southwest counties of north Texas. There is currently a fair amount of rain to our south and southwest and it likely will not reach Frisco. This rain will only be possible in the first 2/3rds of the day, anytime from maybe 4pm and later will have no rain chances at all. Clouds will keep the entire area below 100 degrees for today, highs will likely be in the low to maybe mid 90s.

063009-graphicast1.gif

-- Weather When Posted --

Location: Frisco, TX

Temperature: 80.6°F, Humidity: 57%

Tornado causes extensive damage east of Sarasota!

June 27th, 2009 Sean Toner No comments

So it turns out the storm that kicked off a microburst in Pinellas Park, spun up some pretty strong low level rotation over downtown St Pete then moved south, actually produced an eF-1 Tornado just east of Sarasota! The NWS recently conducted a damage survey of a plant farm with several metal buildings and dozens of greenhouses that were completely destroyed or badly damaged.

The very unfortunate thing I would like to point out here is that this single storm was not severe storm warned or tornado warned at any point in its life cycle which unfortunately may cast a negative light on the hard working folks at the NWS office in Ruskin. I grabbed some archived level 2 radar data from the NCDC and I would like to show you radar snapshots of what forecasters at the NWS would have seen as this storm was unfolding. You can click any of these for full size.

A little background on the day’s forecast first. The area was under a severe thunderstorm watch which had just expired at 9pm. The severe thunderstorm watch notated an elevated risk for an isolated waterspout or tornado to develop along boundary collisions. The day had already brought severe storms widespread across the state, with CAPE values at or around 4000 J/KG. Excerpt from the watch’s discussion quoted below:

SEASONABLY STRONG NLY FLOW ALOFT WILL CONTINUE ACROSS
FL THIS AFTERNOON/EVENING AS DEEP MID LEVEL TROUGH DIGS OFF THE NERN
FL COAST.  AIR MASS REMAINS VERY UNSTABLE…DESPITE EARLIER LINEAR
MCS…WITH SUFFICIENT SHEAR FOR ORGANIZATION INTO LINES/CLUSTERS AND
PERHAPS A BRIEF SUPERCELL OR TWO.  DAMAGING WINDS AND ISOLATED LARGE
HAIL WILL REMAIN PRIMARY THREATS…ALTHOUGH A BRIEF
WATERSPOUT/TORNADO COULD ACCOMPANY STORMS ALONG RESIDUAL SURFACE
BOUNDARIES.

Now with this information in mind, I would be particularly mindful of any rapidly developing low level rotations. Florida tends to not get strong tornadoes, but those we do get form very rapidly and can be hard to detect, generally along strong boundary collisions from multiple thunderstorms. The below summary is an excellent example of this situation. The summary begins below:

062409-0158z-ktbw-howitstarted
06/23/09 9:58pm EDT – This is how the storms began. Note the large cluster of thunderstorms east and southeast of Tampa Bay. These generated an outflow boundary which shows up on the radar very well (thin line of reflectivity from about Parrish through upper Tampa Bay into Tarpon Springs). This boundary was moving very slowly to the west over Tampa Bay. Overall storm motion for the day is to the south-southeast. Another outflow boundary not visible to radar is moving south near New Port Richy. This boundary collision is kicking off new storms near New Port Richy and just offshore in the gulf.

062409-0229z-ktbw-stormsaregrowing
06/23/09 10:29pm EDT – Storms continue to grow larger along the two intersecting outflow boundaries. Gusty winds around 27 knots show up on doppler radar near New Port Richy. Overall storm motion is to the south-southeast.

062409-0259z-ktbw-stormsareborderlinesevere

06/23/09 10:59pm EDT – At this time the storms are very strong, borderline severe. Radar indicates 0.77 inch hail near Anclote Key and into Dunedin with wind gusts to 37 knots in this same area. The leading edge of this storm’s reflectivity now begins to indicate the location of the southerly moving outflow boundary. Note the storm and the westerly moving outflow boundary are now colliding over Pinellas Park. Additionally there apears to be a very small area of possible rotation over Clearwater, however this is the only volume scan this feature appeared in.

062409-0315z-ktbw-microburstwinds
06/23/09 11:15pm EDT – This is the aproximate start time of the microburst damage in Pinellas Park. What we see here is the southward moving outflow with strong storm development to its north, colliding with the now stalled out westerly outflow boundary. Radar indicates 0.93 inch hail near Feather Sound and the Gandy area. Additionally radar velocity now shows 50 knot winds in Highpoint, just west of St. Pete Clearwater Intl Airport. 50 knots is the baseline for a storm to be considered severe. At this time it would have been appropriate to issue the severe storm warning considering the hail size and wind speeds indicated by radar met severe criteria. Additionally the environment was still forecast to be favorable for producing severe weather, so this storm was likely to only intensify.

062409-0319z-ktbw-microburstwinds2
06/23/09 11:19pm EDT – This is the time the microburst likely hit Pinellas Park. You can see the leading edge of the storm had just passed to its south. Additionally I remember looking at this storm live as it was moving through and noticing this scan appeared to have an inflow region right over I-275 and 62nd Ave N, the area impacted by the microburst. The velocity scan shows outbound velocity in this area, paired with very strong inbound just to its west, this is the area where the two outflow boundaries were colliding. Note the radar indicates 0.89 inch hail over old northeast St. Pete, and the southerly moving outflow is now visible on the velocity scan.

062409-0325z-ktbw-microburstwinds3
06/23/09 11:25pm EDT – The next radar volume scan, note the storm has a very well defined Weak Echo Region (WER) just north of St Petersburg. This indicates an area of strong inflow to the storm, with very gusty winds. The velocity scan confirms the outbound winds flowing into this area. Strong inbound winds are indicated by the green color in downtown St Petersburg. Radar indicates 0.65 inch hail in this area.

062409-0330z-ktbw-stronglowlevelrotation
06/23/09 11:30pm EDT – This is a zoomed out version of a radar snap I took and posted on a previous blog entry. This shows very well pronounced low level rotation over downtown St Petersburg. The reflectivity plot on the left shows a classic hook echo, and the velocity plot on the right shows a inbound/outbound couplet which existed in radar volume scans all the way up through 8000 feet! While no confirmed tornado formed from this, I would have strongly considered issuing a tornado warning at this point. Considering the day’s forecast and all available information at the time, this storm appeared ready to produce a tornado at any time. I will re-post the zoomed in version of this radar snap below:
062309-2230-strongrotationintampa
In this zoomed in version, you can clearly see the Weak Echo Region (WER) on the left, with the precipitation wrap around forming the hook echo shape. On the right, you can see a velocity couplet very well defined. Again if I were watching this storm unfolding live, I would consider this storm to be producing a tornado or at least very strong winds. This is actually something which validated as a reader of my site who lives in Coquina Key confirmed damage in her neighborhood from this event! Quote listed below:

We live on Coquina Key and experienced quite a bit of damagage. It was very localized and could have been some sort of tornado. The noise I heard just before the storm broke was the scaries thing I’ve heard.

062409-0335z-ktbw-stormintampabay
06/23/09 11:35pm EDT – The strongest winds with the storm have moved off into the middle of Tampa Bay at this time, though low level rotation still appears to be present. Approximately 10,000 power outages are reported around this time from the strong winds including around Treasure Island.

062409-0345z-ktbw-inmanateecounty
06/23/09 11:45pm EDT – The storm now moves into Manatee County, over Port Manatee first. Emergency Management reports a funnel cloud visible around11:49pm, only 4 minutes after this radar scan. Considering the current radar and velocity plots, it is likely to of occurred closer to 11:45pm and been 4 minutes delayed in reporting, though that’s just an assumption. No well defined rotation shows on this velocity plot, but at the very least you can see areas of strong winds moving ashore near Port Manatee.

062409-0415z-ktbw-sarasotatornado
6/24/09 12:15am EDT – This is just 6 minutes before the storm moved across Fruitville Road and produced the eF-1 tornado. You can see the intense winds and possible rotation right along the Sarasota and Manatee county lines. Outbound winds are reaching 64 knots and inbound winds show 4 knots. 68 knots of shear in this area, this would be capable of producing a weak tornado.

062409-0421z-ktbw-sarasotatornado
06/24/09 12:21pm EDT – This is taken as the storm passes over Fruitville Road to the east of Sarasota. This is likely the time that the tornado began to develop, though radar velocities do not show a very compact circulation in this area. You can see an area on the reflectivity that vaguely resembles a hook, though it is not a very well pronounced one. There is also another area to its east that does have some gate to gate shearing. This is likely the area that the tornado began to develop.

062409-0426z-ktbw-sarasotatornado-zoomedin
06/24/09 12:25pm EDT – This is just a minute before the tornado passed over Fruitville Road and into the Plant Farm. You can see a very small area of shearing winds occuring just southwest of Verna. The highest winds in this area are 66 knots outbound, which equals 75mph. The Plant Farm impacted by this is immediately south of this area of red/green color. Fruitville Road is the pink road traveling west to east across the middle of this image.

The storm gusted out after this point and lost its severity. Again, this storm should have been severe warned back at 11:15pm, and possibly even tornado warned at 11:30pm. Thankfully nobody was hurt during these events (as far as I know). Unfortunately this storm had the potential to be tornado warned up to 55 minutes in advance when the first signs of strong rotation were detected, before the tornado near Sarasota touched town. At the very least this storm should probably have been severe warned as there were numerous volume scans indicating wind speeds exceeding severe criteria.

Below are a few damage pictures taken by the NWS. These are pictures around the Plant Farm east of Sarasota.

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Link to the NWS’s full damage survey is located below:

http://www.srh.noaa.gov/images/tbw/TopNews/TornadoHitsPlantFarm.htm

Location of the tornado damage noted on the google map below:

Severe Thunderstorm Watch for New England area

June 26th, 2009 Sean Toner No comments

Unusual severe weather for a healthy portion of northern New England this afternoon as a Severe Thunderstorm Watch has been issued for northeast New York, northern 2/3 of Vermont, and most of Maine.  This covers Newport Vermont where I frequently visit a friend of mine. Very unusual indeed!

URGENT – IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 515
NWS STORM PREDICTION CENTER NORMAN OK
1215 PM EDT FRI JUN 26 2009

THE NWS STORM PREDICTION CENTER HAS ISSUED A
SEVERE THUNDERSTORM WATCH FOR PORTIONS OF

MUCH OF MAINE
NORTHERN AND CENTRAL NEW HAMPSHIRE
NORTHEAST NEW YORK
NORTHERN AND CENTRAL VERMONT

EFFECTIVE THIS FRIDAY AFTERNOON AND EVENING FROM 1215 PM UNTIL
700 PM EDT.

HAIL TO 2 INCHES IN DIAMETER…THUNDERSTORM WIND GUSTS TO 70
MPH…AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 75
STATUTE MILES NORTH AND SOUTH OF A LINE FROM 30 MILES SOUTHWEST
OF SARANAC LAKE NEW YORK TO 5 MILES SOUTH SOUTHEAST OF HOULTON
MAINE.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED
WATCH OUTLINE UPDATE (WOUS64 KWNS WOU5).

REMEMBER…A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE
FAVORABLE FOR SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH
AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR
THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS
AND POSSIBLE WARNINGS. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY
DO PRODUCE TORNADOES.

DISCUSSION…CLUSTERS OF STRONG/SEVERE THUNDERSTORMS ARE EXPECTED TO
CONTINUE TO DEVELOP THROUGH THE AFTERNOON ACROSS THE WATCH AREA AS
UPPER SHORTWAVE TROUGH APPROACHES FROM THE WEST.  POCKETS OF HEATING
AND RATHER COOL TEMPERATURES ALOFT WILL PROMOTE A RISK OF HAIL AND
DAMAGING WINDS IN STRONGER CELLS.

AVIATION…A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 2 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60
KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 450. MEAN STORM
MOTION VECTOR 27025.

…HART

-- Weather When Posted --

Location: Newport, VT

Temperature: 75.2°F, Humidity: 60%

Microburst damage in Pinellas Park from overnight storms

June 24th, 2009 Sean Toner No comments

The National Weather Service has conducted a damage survey to the multiple mobile homes who lost their roofs in Pinellas Park and concluded this was microburst damage. Straight-line winds around 60mph from the northwest to the southeast occurred near 62nd Ave N and I-275 overnight June 23 just after 11pm. Below is a brief damage summary and link to the damage survey with photos included.

An area of strong thunderstorms moved south across central Pinellas county Tuesday June 23, 2009
between 11 PM and midnight.  The thunderstorms generally produced winds of 40 to 50 MPH, however
a micorburst occurred in Pinellas Park which produced winds of  approximately 60 MPH which caused
damage to numerous homes in the Southernaire Mobile Home Park on 62nd Ave N, just west of
Interstate 275.  One tree and numerous limbs were downed just northwest of the mobile home park
along 27th St North from 59th Ave N to 62nd Ave N.  Linear damage occurred from northwest to southeast
in this area which indicates this was the result of straight line winds and not a tornado.  Most damage in
the mobile home park was the result of wind getting under carports and lifting them up and over
homes, in some cases taking part of the roof off the home where the carport was attached.