Tropical Storm Debby

[Konstantinos]

80% Chance during the next 48 hours:

ZCZC MIATWOAT ALL

TTAA00 KNHC DDHHMM

TROPICAL WEATHER OUTLOOK

NWS NATIONAL HURRICANE CENTER MIAMI FL

200 AM EDT SAT JUN 23 2012

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...

1. SHOWER AND THUNDERSTORM ACTIVITY IS GRADUALLY INCREASING IN

ASSOCIATION WITH A LARGE LOW PRESSURE SYSTEM LOCATED ABOUT 175

MILES NORTH OF THE YUCATAN PENNISULA. RECENT SATELLITE DATA AND

SURFACE OBSERVATIONS INDICATE THAT THE CIRCULATION OF THE LOW

REMAINS QUITE BROAD WITH A LARGE AREA OF LIGHT WINDS NEAR THE

CENTER. ENVIRONMENTAL CONDITIONS ARE CONDUCIVE FOR A TROPICAL

DEPRESSION TO FORM DURING THE NEXT DAY OR SO AS THIS DISTURBANCE

DRIFTS NORTHWARD. THIS SYSTEM HAS A HIGH CHANCE...80 PERCENT...OF

BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS. INTERESTS

ALONG THE UNITED STATES GULF COAST SHOULD MONITOR THE PROGRESS OF

THIS LOW THROUGH THE WEEKEND. HEAVY RAINS AND LOCALIZED FLOODING

ARE POSSIBLE ACROSS THE YUCATAN PENINSULA...WESTERN CUBA...AND

SOUTHERN FLORIDA OVER THE NEXT DAY OR SO.

ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE

NEXT 48 HOURS.

$$

FORECASTER CANGIALOSI/BEVEN

NNNN

http://www.nhc.noaa.gov/gtwo_atl.shtml

[knocker]

Latest Sat from the Gulf of Mexico.

[Iceberg]

97l is following the weirdness of the season.see paths below.

We have gfs which takes a future ts over orlando and central florida in to the atlantic and then goes on to form a hurricane.

ECM takes it to the new orleans and then sharp west to the mexico boarder, hwrf is pretty similar to ecm, while gfdl takes it uptowards New Orleans and then east and north into the us belly.

As expected with all the above options, it has anywhere from 3 days to 6 in which to grow and strength.

NHC now gives a 90% chance of development. ATM is is strongly sheared, but circulation is very evident and as soon as the shear weakens we will get a TS IMHO.

[knocker]

Latest enhanced water vapour.

[Ross B]

Cheers guys - I'm keeping an eye on this one as I'll be on the west coast of Florida in 2 days time. My flight takes off tomorrow morning so I doubt I'll know the track until I arrive tomorrow night. It's looking wet either way!

[Konstantinos]

Cheers guys - I'm keeping an eye on this one as I'll be on the west coast of Florida in 2 days time. My flight takes off tomorrow morning so I doubt I'll know the track until I arrive tomorrow night. It's looking wet either way!

So, will we have photos and videos from you?

[Ross B]

So, will we have photos and videos from you?

If anything heads my way then yes, I'm not chasing it though!

[Iceberg]

This has been classified as ts debbie at 40kts with Nhc discussion to start at 22.00 BST, very clear Llcc but very badly sheared

[Paranoid]

If 96L is TS Debbie, it will be the earliest 4th storm on record by almost two weeks (current record is Hurricane Dennis of 2005, which formed on the 5th July).

[Iceberg]

Forgot to add 12z ECM still goes for a texas hit t120 or so due to a very strong upper level high giving Debbie a 90 degree turn before it approaches new Orleans. A possibility And most likely imho

[Somerset Squall]

Not meaning to be pedantic but the spelling is Debby not Debbie.

Certainly very lop sided convection wise at present. This is due to the upper level low in the western Gulf Of Mexico pumping shear and dry air into the western quadrant of Debby, exposing the LLC.

Latest enhanced water vapour.

Thanks for the image Knocker. Shows the upper level low responsible for the dry air and shear to the west of Debby.

[Somerset Squall]

TROPICAL STORM DEBBY DISCUSSION NUMBER 1

NWS NATIONAL HURRICANE CENTER MIAMI FL AL042012

400 PM CDT SAT JUN 23 2012

AIRCRAFT RECONNAISSANCE...SATELLITE...AND BUOY DATA INDICATE THAT

THE CIRCULATION ASSOCIATED WITH THE AREA OF LOW PRESSURE IN THE

GULF OF MEXICO HAS BECOME SUFFICIENTLY DEFINED TO CLASSIFY THIS

SYSTEM AS A TROPICAL STORM. THE INITIAL INTENSITY IS BASED ON A

HIGHEST 1000-FT FLIGHT-LEVEL WIND OF 61 KT AND SFMR WINDS NEAR 45

KT. THESE WINDS ARE ONLY OCCURRING TO THE EAST OF THE CENTER.

DEBBY IS MOVING SLOWLY NORTHWARD...OR 360 DEGREES AT 5 KT. THE

CYCLONE IS IN A WEAK STEERING ENVIRONMENT BETWEEN TWO MID-LEVEL

RIDGES LOCATED OVER THE GREATER ANTILLES AND THE SOUTHERN UNITED

STATES...AND DEBBY IS NOT EXPECTED TO MOVE MUCH DURING THE NEXT

COUPLE OF DAYS. THE TRACK GUIDANCE IS SPLIT IN TWO BRANCHES...WITH

THE GFS AND GFDL SHOWING AN EASTWARD MOTION ACROSS FLORIDA...AND

THE REST OF THE MODELS BRINGING DEBBY WESTWARD ACROSS THE NORTHERN

GULF TOWARDS TEXAS. EVEN THOUGH THE DETERMINISTIC GFS SHOWS AN

EASTWARD TRACK...MORE THAN HALF OF THE GFS ENSEMBLE MEMBERS ARE IN

AGREEMENT WITH THE WESTWARD-MOVING MODELS...MAKING THE WESTWARD

SCENARIO SEEM MORE LIKELY. IT IS IMPORTANT TO NOTE TOO THAT THE

ECMWF MODEL SHOWS A FASTER WESTWARD MOTION THAN INDICATED IN THE

NHC FORECAST...SO IT IS POSSIBLE THAT DEBBY COULD REACH THE COAST

EARLIER THAN INDICATED.

DEBBY IS CURRENTLY A SHEARED CYCLONE WITH NEARLY ALL OF THE DEEP

CONVECTION LOCATED IN A CURVED BAND TO THE EAST OF THE CENTER.

HOWEVER...AN UPPER-LEVEL LOW OVER THE NORTHWESTERN GULF OF MEXICO

IS FORECAST TO DIG SOUTHWESTWARD...WHICH WILL RESULT IN A DECREASE

OF VERTICAL SHEAR AFFECTING THE SYSTEM...AND A GREATER CHANCE OF

INTENSIFICATION OVER THE NEXT FEW DAYS. BECAUSE THE OFFICIAL TRACK

FORECAST IS SO DIFFERENT FROM THE GFS SOLUTION...THE GFS FIELDS USED

BY THE SHIPS AND LGEM MODELS ARE NOT LIKELY TO BE REPRESENTATIVE OF

THE CONDITIONS ENCOUNTERED BY DEBBY. THE NHC FORECAST THEREFORE

SHOWS MORE STRENGTHENING THAN INDICATED BY THE INTENSITY GUIDANCE.

DEBBY IS THE EARLIEST 4TH STORM IN THE HISTORICAL RECORDS...

SURPASSING HURRICANE DENNIS OF 2005...WHICH BECAME A TROPICAL STORM

ON JULY 5TH.

FORECAST POSITIONS AND MAX WINDS

INIT 23/2100Z 26.2N 87.6W 45 KT 50 MPH

12H 24/0600Z 26.9N 87.8W 45 KT 50 MPH

24H 24/1800Z 27.3N 88.1W 50 KT 60 MPH

36H 25/0600Z 27.4N 88.5W 50 KT 60 MPH

48H 25/1800Z 27.5N 89.5W 55 KT 65 MPH

72H 26/1800Z 27.5N 91.5W 55 KT 65 MPH

96H 27/1800Z 27.5N 93.5W 60 KT 70 MPH

120H 28/1800Z 27.5N 95.0W 60 KT 70 MPH

$$

FORECASTER BERG/AVILA

[Konstantinos]

Unfortunately it is not going to Florida dear RossB.

Tropical Storm "Debby" has formed in the central Gulf of Mexico.

A tropical storm warning has been issued for the Louisiana coast from the mouth of the Pearl River to Morgan City - not including the city of New Orleans or Lake Pontchartrain. Debby is centered about 220 miles south-southeast of the mouth of the Mississippi River with maximum sustained winds of 50 mph, moving slowly north. A turn to the west is expected on Sunday, taking the center of the storm over the northern Gulf of Mexico during the next few days.

Get the latest on this storm, including forecasts and graphics, by visiting the NHC website at www.hurricanes.gov

http://www.facebook.com/photo.php?fbid=369685176430302&set=a.126275484104607.22530.112957945436361&type=1&theater

[Somerset Squall]

It's unusual to see such strong model disagreement. Though NHC have gone with the westward tracking models, the forecast confidence is low. I don't think the eastwards tracking models can be completely discounted at this stage. It'll be interesting to see what happens. NHC are forecasting the upper level low to move away too which may allow Debby to slowly become more symmetrical as shear eases. The longer Debby stays over water the more chance the large storm has of becoming a hurricane.

Edited June 23, 2012 by Somerset Squall

[Iceberg]

very early to be saying this but debby(thxs), is bursting with danger potential.

we have a system with a good LLCC now, convection is readily flaring out of reach of the shear and is high, deep and cold. Winds in the convection look to be high 40's kts maybe low 50's. NHC are progging her to become a hurricane.

Added to this we have our 29C waters under her.

Path is very very problematically, NHC are going for the Texas hit...but the 00Z models have moved decisively away from this, with only hwrf going for texas now, gfdl still puts the us ridge weaker and finds a path for debby to move into florida, (the gfs based gfdl also does but this is no big surprise), ECM 00Z is the big problem though as it develops quiet a hefty hurricane and has it so slow moving on an approach to New Orleans that it would dump massive maybe record breaking amounts of rain and then hit it with a NE quad and storm surge.

So the next nhc update might present us with a big track change and oddles of uncertainty, don't wish this kind of system on them as its as difficult to forecast as it comes for a high profile early season storm.

[Iceberg]

I like the comment from the latest advisory below.

" THE TRACK FORECAST FOR THIS STORM IS EXTREMELY CHALLENGING. THE SYNOPTIC REASONING IN PREVIOUS

ADVISORIES WAS BASED ON A MID-LEVEL RIDGE BUILDING TO THE NORTH OF

THE TROPICAL CYCLONE...WHICH WOULD CAUSE DEBBY TO MOVE TOWARD THE

NORTHWEST GULF OF MEXICO COAST IN SEVERAL DAYS. THAT TRACK

SCENARIO WAS SUPPORTED BY THE ECMWF MODEL...WHICH HAS BEEN THE

BEST-PERFORMING GUIDANCE OVER THE PAST FEW YEARS. HOWEVER...THE

0000 RUN OF THAT MODEL HAS SHIFTED SUBSTANTIALLY TO THE NORTH AND

EAST OF THE PREVIOUS RUNS. THE U.K. MET. OFFICE MODEL HAS ALSO

SHIFTED SIGNIFICANTLY TO THE RIGHT. IN FACT...ONLY THE HWRF MODEL

IS CLOSE TO THE PREVIOUS OFFICIAL FORECASTS...AND EVEN IT IS TO THE

NORTH OF THEM. THEREFORE AN UNUSUALLY LARGE RIGHTWARD ADJUSTMENT

TO THE NHC FORECAST IS REQUIRED...AND ADDITIONAL SHIFTS TO THE

NORTH AND EAST MAY BE NECESSARY IN SUBSEQUENT ADVISORY PACKAGES."

So they don't know where the centre really is with any certainty. Worth mentioning just how slow she is forecasted to be, 6mph or roughly the speed of a good marathon runner..!

[knocker]

Latest Sat.

[Ross B]

Hmmm, where will it go!! Really do not want it to be a hurricane if it heads for Florida as i will be evacuated, record rainfall would be interesting though as long as i arrive before it starts! Current waiting at the airport on my flight which has been delayed. Cameras packed just in case!!

[knocker]

Rain from the system well into Florida. The Tampa radar.

[Somerset Squall]

It looks as if Debby's LLC has reformed northeast closer to the deep convection this morning. The convection seems to be attempting to wrap around the LLC this morning aswell, though the southwest quadrant of Debby is still largely convectionless. Models shifted northeastwards this morning as Iceberg says, and it is still very difficult to predict with any certainty just where Debby is going to go.

The upper level low looks a little weaker over the western GOM this morning. Debby has also increased it's distance from it, meaning Debby will likely strengthen later today as the convection becomes more intergrated with the LLC as the shear may begin to ease.

[Cookie]

[Cookie]

http://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=2131

Debby's place in history

Remarkably, Debby's formation on June 23 comes a full two months ahead of the usual formation date of the season's fourth storm in the Atlantic, August 23. Debby's formation beats by twelve days the previous record for formation of the fourth named storm of the year in the Atlantic, set in 2005, when Hurricane Dennis was named on July 5. An early start to the Atlantic hurricane season has been increasingly common in recent years. In 2008, I blogged about the research of Dr. Jim Kossin of the University of Wisconsin, who published a 2008 paper in Geophysical Research Letters, titled "Is the North Atlantic hurricane season getting longer?" He concluded that yes, there is a "apparent tendency toward more common early- and late-season storms that correlates with warming Sea Surface Temperature but the uncertainty in these relationships is high". Three out of four of this year's early quartet of storms--Alberto, Beryl, and Debby--formed in ocean areas that were more than 1°F above average, which is an unusually high amount of warmth. We should expect to see more early-season Atlantic tropical storms as a consequence of global warming, since cool ocean temperatures are a key impediment to formation of such storms. However, this assumes that factors such as wind shear and atmospheric stability won't grow more hostile for tropical cyclone formation during the early part of hurricane season, and this is uncertain. If we do end up seeing a substantial increase in early-season tropical storms as a consequence of global warming, this is not necessarily a bad thing. Early-season tropical storms are often more boon than bane, bringing much-needed drought-busting rains, like Tropical Storm Beryl did for North Florida last month. With drought frequency and intensity predicted to increase for much of the Gulf Coastal states in coming decades, an increase in rainfall from early-season tropical storms may do more good than the damages inflicted by the high winds and flooding these storms may bring. There is typically a lot of wind shear around in May, June, and July, making it difficult for early season storms to reach major hurricane status. According to Wunderground's list of major early-season hurricanes, since record keeping began in 1851, there has been only one major hurricane in May, two in June, and nine in July. Three of these occurred in the past ten years, so there has not as yet been an observable large increase in early-season major hurricanes due to global warming.

[knocker]

Latest Talahassee radar.

[lorenzo]

Storm tracks from the Twittersphere.. models not in good agreement then !!

Surfs Up @ Pensacola

http://www.nhc.noaa....ml/241455.shtml

AT 1000 AM CDT...1500 UTC...THE CENTER OF TROPICAL STORM DEBBY WAS

LOCATED NEAR LATITUDE 28.0 NORTH...LONGITUDE 86.2 WEST. DEBBY IS

MOVING TOWARD THE NORTHEAST NEAR 6 MPH...9 KM/H...BUT LITTLE MOTION

IS EXPECTED DURING THE NEXT 12 TO 24 HOURS. A GRADUAL TURN TOWARD

THE WEST IS FORECAST THEREAFTER. THE FORECAST TRACK WILL KEEP THE

CENTER OF DEBBY MEANDERING OVER THE NORTHERN GULF OF MEXICO DURING

THE NEXT FEW DAYS.

MAXIMUM SUSTAINED WINDS ARE NEAR 60 MPH...95 KM/H...WITH HIGHER

GUSTS. SOME SLIGHT STRENGTHENING IS POSSIBLE DURING THE NEXT 48

HOURS.

TROPICAL-STORM-FORCE WINDS EXTEND OUTWARD UP TO 200 MILES...325 KM

FROM THE CENTER MAINLY TO THE NORTH AND EAST OF THE CENTER. BALD

POINT IN THE FLORIDA BIG BEND RECENTLY REPORTED SUSTAINED WINDS OF

52 MPH...84 KM/H.

THE LATEST ESTIMATED MINIMUM CENTRAL PRESSURE FROM A RECONNAISSANCE

AIRCRAFT WAS 994 MB...29.35 INCHES.

This track graphic is my favourite today LOL !

Edited June 24, 2012 by lorenzo

[knocker]

A severe thunderstorm warning out for Tampa.