Tropical Storm Debby has formed in the Gulf of Mexico
Tropical Storm Debby has been named by the National Hurricane Center this afternoon after hurricane hunters investigated Invest 96L and found a solid closed circulation, with maximum winds of 50mph and gusts up to 65mph. All interests along the Gulf of Mexico coast should pay attention to the progress of Debby. Debby is drifting north at 5mph. The storm has brought heavy rains to Western Cuba, South Florida, and Mexico's Yucatan Peninsula over the past two days, but the disturbance's heaviest rains are located well offshore over the Eastern Gulf of Mexico, where heavy thunderstorms are generating winds near tropical storm-force. A buoy 243 miles west of Naples, FL measured sustained winds of 31 mph, gusting to 38 mph, with 10-foot waves, at 8 am EDT Saturday morning. Our Wundermap for the surrounding ocean areas shows a large region of the northern and eastern Gulf of Mexico is experiencing winds of 20 - 30 mph.
Visible satellite loops show an unorganized tropical cyclone with an obvious surface circulation, though the thunderstorm activity is well displaced to the east. The heavy thunderstorm activity is slowly expanding and growing more intense. Upper-level winds out of the west continue to create moderate 10 - 20 knots of wind shear over the region, though that is expected to increase over the next few days. Water vapor satellite loops show a region of dry air over the central Gulf of Mexico, which will continue to interfere with Debby's development and make it hard for the west side of the circulation to maintain heavy thunderstorms. Ocean temperatures are about 28.5°C (83°F) in the Central Gulf of Mexico, which is about 1°F above average.
Figure 1. Saturday afternoon satellite image of Tropical Storm Debby in the Gulf of Mexico.
Figure 2. Saturday afternoon forecast track for Tropical Storm Debby.
Forecast for Debby
The National Hurricane Center is forecasting Debby to remain a tropical cyclone over the next 5 days as it drifts north and then west toward Texas. The Hurricane Center is forecasting a very slow progression of the storm, with a potential landfall not occurring until Friday. However, most of the models that predict the turn to the west suggest landfall will happen before or around Wednesday. The models are still generally split on the forecast for Debby; by Monday, the majority of the reliable models, including the ECMWF, NOGAPS, HWRF, and UKMET, agree that a ridge of high pressure will build in over the Southern U.S., forcing Debby west across the Gulf of Mexico and into South Texas by Wednesday. However, the GFS model, which has been our 2nd most reliable track model over the past two years (behind the ECMWF), has consistently been predicting that a trough of low pressure pushing off of the U.S. East Coast will be capable of grabbing the disturbance and accelerating it to the northeast across Florida north of Tampa Bay on Monday. The GFDL model splits the difference between these extremes and takes Debby north to a landfall near the Alabama/Florida border on Tuesday. The predicted track west to Texas is still the most likely outcome, though it remains a low-confidence forecast. In terms of intensity, none of the models is predicting Debby will become a hurricane, nor is the Hurricane Center. Though sea surface temperature is warm (and around 1°F above average), the actual heat content of the Gulf is relatively low. Wind shear is predicted to remain moderately strong through Sunday, but will increase to 30+ knots by Tuesday.
Debby's place in history (by Jeff Masters)
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 a large increase in early-season major hurricanes due to global warming.
References
Kossin, J., 2008, "Is the North Atlantic hurricane season getting longer?", Geophysical Research Letters, Vol. 35, L23705, doi:10.1029/2008GL036012, 2008.
Angela and Jeff
Reader Comments
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Tropical Storm DEBBY
...DEBBY REMAINS STATIONARY OVER THE CENTRAL GULF OF MEXICO... ...HEAVY SQUALLS AFFECTING PORTIONS OF WEST-CENTRAL AND SOUTHWESTERN FLORIDA...
10:00 PM CDT Sat Jun 23
Location: 26.3°N 87.5°W
Moving: Stationary
Min pressure: 998 mb
Max sustained: 50 mph
"It's an Imperial Battle Station!"
Depends on whether Stewart is doing the night shift or not.
Still a ways to go, but it's looking more likely as time passes.
As it is now, any number could come up.
After she busts the trough
WU After Dark
I expect a hurricane within the next five days as well, but we should definitely be conservative.
thanks Chasey, you too.
So good to see you!!
moved slightly north. It was at 26.1 earlier.
It's like watching a herd of turtles stampede thru a peanut butter patch.
I was referring to a surface to low-level (steering layer) ridge. The 105 to 107 degrees you are experiencing are associated with an upper ridge over the western US...
Now we know the possibility of this being a hurricane south of our coastline...Have to watch the models extra carefully now
WTNT44 KNHC 240257
TCDAT4
TROPICAL STORM DEBBY DISCUSSION NUMBER 2
NWS NATIONAL HURRICANE CENTER MIAMI FL AL042012
1000 PM CDT SAT JUN 23 2012
DEBBY IS GRADUALLY SHOWING SIGNS OF IMPROVED ORGANIZATION AS THE
UPPER-LEVEL SHEAR SHIFTS FROM SOUTHWESTERLY TO MORE OF A SOUTHERLY
COMPONENT. SHIP ZCDJ2 LOCATED ABOUT 80 NMI EAST OF THE CENTER AND
NEAR NOAA BUOY 42003 REPORTED A PRESSURE OF 1001.6 MB AND 38 KT
WINDS AT 24/00Z. BASED ON THIS INFORMATION...THE CENTRAL PRESSURE
IS CONSERVATIVELY ESTIMATED TO BE 998 MB. AIRCRAFT RECONNAISSANCE
DATA AT 23/2020Z INDICATED 850 MB FLIGHT-LEVEL WINDS OF 61 KT IN
THE NORTHEAST QUADRANT...WHICH IS EQUAL TO ABOUT 49 KT SURFACE
WINDS. CONVECTION WAS SOMEWHAT MEAGER AT THAT...BUT SINCE THEN HAS
INCREASED RATHER MARKEDLY IN THAT AREA. THEREFORE THE INITIAL
INTENSITY ESTIMATE IS A SOLID 45 KT.
DEBBY HAS BEEN NEARLY STATIONARY DURING THE PAST 6 HOURS. MULTIPLE
LOW-LEVEL VORTICES HAVE BEEN OUT FROM UNDERNEATH THE EASTERN
SEMICIRCLE CONVECTIVE CLOUD MASS ABOUT A MEAN CENTER OF ROTATION OF
A LARGER GYRE...AND THE LOCATION OF THE LARGER STATIONARY GYRE IS
THE ADVISORY POSITION. ALTHOUGH THERE MAY BE SOME SLIGHT
NORTHEASTWARD MOTION DUE TO REDEVELOPMENT OF THE CENTER CLOSER TO
THE DEEP CONVECTION...THE GENERAL MOTION FOR THE NEXT 24 HOURS OR
SO SHOULD BE SLOWLY POLEWARD. THE LONGWAVE PATTERN ACROSS THE U.S.
HAS A DEEPENING TROUGH OFF THE WEST COAST...WHICH IS CREATING
DOWNSTREAM RIDGING ACROSS THE CENTRAL AND EASTERN UNITED STATES.
THIS INCREASED RIDGING IS REFLECTED BY 20-40 METER 500 MB HEIGHT
RISES AT 00Z ACROSS THE CENTRAL AND SOUTHERN PLAINS...AND EXTENDING
AS FAR EAST AS THE CAROLINA COASTS. THIS BLOCKING RIDGE PATTERN TO
THE NORTH OF DEBBY IS EXPECTED TO GRADUALLY TURN THE CYCLONE
WESTWARD ACROSS THE NORTH-CENTRAL GULF OF MEXICO BY 36-48
HOURS...WITH A CONTINUED WESTWARD MOTION ACROSS THE NORTHWESTERN
GULF AFTER THAT. ALL OF THE AVAILABLE NHC MODEL GUIDANCE...EXCEPT
FOR THE GFS AND GFS-ENSEMBLE MODELS...SUPPORTS THE GENERAL WESTWARD
MOTION SCENARIO. THE MAIN REASON THAT THE GFS MOVES DEBBY EASTWARD
ACROSS THE NORTHEASTERN GULF IS DUE TO IT HAVING A WEAKER AND MORE
VERTICALLY SHALLOW STORM DEPICTED IN THE MODEL. GIVEN THE EXPECTED
FAVORABLE UPPER-LEVEL FLOW PATTERN WITH WEAKER VERTICAL SHEAR
FORECAST TO DEVELOP AFTER 24 HOURS...A DEEPER AND MORE ROBUST
WESTWARD MOVING TROPICAL CYCLONE AS DEPICTED IN THE
ECMWF...UKMET... NOGAPS MODELS SEEMS A MORE REASONABLE SCENARIO.
THE OFFICIAL FORECAST TRACK IS JUST AN UPDATE OF THE PREVIOUS
ADVISORY TRACK.
MODERATE SOUTHWESTERLY VERTICAL WIND SHEAR IS EXPECTED TO GRADUALLY
GIVE WAY TO SOUTHERLY AND EVENTUALLY SOUTHEASTERLY WEAKER WIND
SHEAR BY 36-48 HOURS AS AN UPPER-LEVEL LOW NORTHWEST OF THE CYCLONE
MOVES SOUTHWESTWARD...WHICH ALLOWS DEBBY TO MOVE UNDERNEATH A 200
MB RIDGE AXIS. THE OFFICIAL INTENSITY FORECAST LEANS TOWARD THE
ECMWF MODEL...WHICH IS FORECASTING A HURRICANE CENTRAL PRESSURE BY
96 HOURS...AND IS ABOVE THE GFS-BASED SHIPS AND LGEM MODELS SINCE
THAT OUTPUT LIKELY DOES NOT REPRESENT THE ENVIRONMENTAL CONDITIONS
THAT DEBBY WILL ENCOUNTER. THE OFFICIAL INTENSITY FORECAST IS A
LITTLE HIGHER THAN THE PREVIOUS ADVISORY...AND BRINGS DEBBY TO
HURRICANE STRENGTH BY 72 HOURS.
FORECAST POSITIONS AND MAX WINDS
INIT 24/0300Z 26.3N 87.5W 45 KT 50 MPH
12H 24/1200Z 26.7N 87.8W 50 KT 60 MPH
24H 25/0000Z 27.0N 88.1W 50 KT 60 MPH
36H 25/1200Z 27.1N 88.8W 55 KT 65 MPH
48H 26/0000Z 27.2N 89.8W 60 KT 70 MPH
72H 27/0000Z 27.2N 91.8W 65 KT 75 MPH
96H 28/0000Z 27.2N 93.7W 70 KT 80 MPH
120H 29/0000Z 27.2N 95.2W 70 KT 80 MPH
$$
FORECASTER STEWART
which one is dat?
000
WTNT44 KNHC 240257
TCDAT4
TROPICAL STORM DEBBY DISCUSSION NUMBER 2
NWS NATIONAL HURRICANE CENTER MIAMI FL AL042012
1000 PM CDT SAT JUN 23 2012
DEBBY IS GRADUALLY SHOWING SIGNS OF IMPROVED ORGANIZATION AS THE
UPPER-LEVEL SHEAR SHIFTS FROM SOUTHWESTERLY TO MORE OF A SOUTHERLY
COMPONENT. SHIP ZCDJ2 LOCATED ABOUT 80 NMI EAST OF THE CENTER AND
NEAR NOAA BUOY 42003 REPORTED A PRESSURE OF 1001.6 MB AND 38 KT
WINDS AT 24/00Z. BASED ON THIS INFORMATION...THE CENTRAL PRESSURE
IS CONSERVATIVELY ESTIMATED TO BE 998 MB. AIRCRAFT RECONNAISSANCE
DATA AT 23/2020Z INDICATED 850 MB FLIGHT-LEVEL WINDS OF 61 KT IN
THE NORTHEAST QUADRANT...WHICH IS EQUAL TO ABOUT 49 KT SURFACE
WINDS. CONVECTION WAS SOMEWHAT MEAGER AT THAT...BUT SINCE THEN HAS
INCREASED RATHER MARKEDLY IN THAT AREA. THEREFORE THE INITIAL
INTENSITY ESTIMATE IS A SOLID 45 KT.
DEBBY HAS BEEN NEARLY STATIONARY DURING THE PAST 6 HOURS. MULTIPLE
LOW-LEVEL VORTICES HAVE BEEN OUT FROM UNDERNEATH THE EASTERN
SEMICIRCLE CONVECTIVE CLOUD MASS ABOUT A MEAN CENTER OF ROTATION OF
A LARGER GYRE...AND THE LOCATION OF THE LARGER STATIONARY GYRE IS
THE ADVISORY POSITION. ALTHOUGH THERE MAY BE SOME SLIGHT
NORTHEASTWARD MOTION DUE TO REDEVELOPMENT OF THE CENTER CLOSER TO
THE DEEP CONVECTION...THE GENERAL MOTION FOR THE NEXT 24 HOURS OR
SO SHOULD BE SLOWLY POLEWARD. THE LONGWAVE PATTERN ACROSS THE U.S.
HAS A DEEPENING TROUGH OFF THE WEST COAST...WHICH IS CREATING
DOWNSTREAM RIDGING ACROSS THE CENTRAL AND EASTERN UNITED STATES.
THIS INCREASED RIDGING IS REFLECTED BY 20-40 METER 500 MB HEIGHT
RISES AT 00Z ACROSS THE CENTRAL AND SOUTHERN PLAINS...AND EXTENDING
AS FAR EAST AS THE CAROLINA COASTS. THIS BLOCKING RIDGE PATTERN TO
THE NORTH OF DEBBY IS EXPECTED TO GRADUALLY TURN THE CYCLONE
WESTWARD ACROSS THE NORTH-CENTRAL GULF OF MEXICO BY 36-48
HOURS...WITH A CONTINUED WESTWARD MOTION ACROSS THE NORTHWESTERN
GULF AFTER THAT. ALL OF THE AVAILABLE NHC MODEL GUIDANCE...EXCEPT
FOR THE GFS AND GFS-ENSEMBLE MODELS...SUPPORTS THE GENERAL WESTWARD
MOTION SCENARIO. THE MAIN REASON THAT THE GFS MOVES DEBBY EASTWARD
ACROSS THE NORTHEASTERN GULF IS DUE TO IT HAVING A WEAKER AND MORE
VERTICALLY SHALLOW STORM DEPICTED IN THE MODEL. GIVEN THE EXPECTED
FAVORABLE UPPER-LEVEL FLOW PATTERN WITH WEAKER VERTICAL SHEAR
FORECAST TO DEVELOP AFTER 24 HOURS...A DEEPER AND MORE ROBUST
WESTWARD MOVING TROPICAL CYCLONE AS DEPICTED IN THE
ECMWF...UKMET... NOGAPS MODELS SEEMS A MORE REASONABLE SCENARIO.
THE OFFICIAL FORECAST TRACK IS JUST AN UPDATE OF THE PREVIOUS
ADVISORY TRACK.
MODERATE SOUTHWESTERLY VERTICAL WIND SHEAR IS EXPECTED TO GRADUALLY
GIVE WAY TO SOUTHERLY AND EVENTUALLY SOUTHEASTERLY WEAKER WIND
SHEAR BY 36-48 HOURS AS AN UPPER-LEVEL LOW NORTHWEST OF THE CYCLONE
MOVES SOUTHWESTWARD...WHICH ALLOWS DEBBY TO MOVE UNDERNEATH A 200
MB RIDGE AXIS. THE OFFICIAL INTENSITY FORECAST LEANS TOWARD THE
ECMWF MODEL...WHICH IS FORECASTING A HURRICANE CENTRAL PRESSURE BY
96 HOURS...AND IS ABOVE THE GFS-BASED SHIPS AND LGEM MODELS SINCE
THAT OUTPUT LIKELY DOES NOT REPRESENT THE ENVIRONMENTAL CONDITIONS
THAT DEBBY WILL ENCOUNTER. THE OFFICIAL INTENSITY FORECAST IS A
LITTLE HIGHER THAN THE PREVIOUS ADVISORY...AND BRINGS DEBBY TO
HURRICANE STRENGTH BY 72 HOURS.
FORECAST POSITIONS AND MAX WINDS
INIT 24/0300Z 26.3N 87.5W 45 KT 50 MPH
12H 24/1200Z 26.7N 87.8W 50 KT 60 MPH
24H 25/0000Z 27.0N 88.1W 50 KT 60 MPH
36H 25/1200Z 27.1N 88.8W 55 KT 65 MPH
48H 26/0000Z 27.2N 89.8W 60 KT 70 MPH
72H 27/0000Z 27.2N 91.8W 65 KT 75 MPH
96H 28/0000Z 27.2N 93.7W 70 KT 80 MPH
120H 29/0000Z 27.2N 95.2W 70 KT 80 MPH
$$
FORECASTER STEWART
I think im going to have to agree with ya on that
i saw a link some where earlier that was predicting a pretty strong system in a couple days
48 hrs
The Talking Heads is perfect music to pump a ridge to...
...WHICH IS CREATING
DOWNSTREAM RIDGING ACROSS THE CENTRAL AND EASTERN UNITED STATES.
THIS INCREASED RIDGING IS REFLECTED BY 20-40 METER 500 MB HEIGHT
RISES AT 00Z ACROSS THE CENTRAL AND SOUTHERN PLAINS..
Sounds dramatic --escaping from the gulf -- on the run over Florida
I'm not so crazy about a stall, because that can cause the training over us. Everything around is here is icky from rain and humidity.
How is the weather in Grand Cayman?
GIVE WAY TO SOUTHERLY AND EVENTUALLY SOUTHEASTERLY WEAKER WIND
SHEAR BY 36-48 HOURS AS AN UPPER-LEVEL LOW NORTHWEST OF THE CYCLONE
MOVES SOUTHWESTWARD...WHICH ALLOWS DEBBY TO MOVE UNDERNEATH A 200
MB RIDGE AXIS. THE OFFICIAL INTENSITY FORECAST LEANS TOWARD THE
ECMWF MODEL...WHICH IS FORECASTING A HURRICANE CENTRAL PRESSURE BY
96 HOURS...AND IS ABOVE THE GFS-BASED SHIPS AND LGEM MODELS SINCE
THAT OUTPUT LIKELY DOES NOT REPRESENT THE ENVIRONMENTAL CONDITIONS
THAT DEBBY WILL ENCOUNTER. THE OFFICIAL INTENSITY FORECAST IS A
LITTLE HIGHER THAN THE PREVIOUS ADVISORY...AND BRINGS DEBBY TO
HURRICANE STRENGTH BY 72 HOURS."
Good job! I need to get my hands on that software.
DEBBY HAS BEEN NEARLY STATIONARY DURING THE PAST 6 HOURS. MULTIPLE
LOW-LEVEL VORTICES HAVE BEEN OUT FROM UNDERNEATH THE EASTERN
SEMICIRCLE CONVECTIVE CLOUD MASS ABOUT A MEAN CENTER OF ROTATION OF
A LARGER GYRE...AND THE LOCATION OF THE LARGER STATIONARY GYRE IS
THE ADVISORY POSITION. ALTHOUGH THERE MAY BE SOME SLIGHT
NORTHEASTWARD MOTION DUE TO REDEVELOPMENT OF THE CENTER CLOSER TO
THE DEEP CONVECTION...THE GENERAL MOTION FOR THE NEXT 24 HOURS OR
SO SHOULD BE SLOWLY POLEWARD. THE LONGWAVE PATTERN ACROSS THE U.S.
HAS A DEEPENING TROUGH OFF THE WEST COAST...WHICH IS CREATING
DOWNSTREAM RIDGING ACROSS THE CENTRAL AND EASTERN UNITED STATES.
THIS INCREASED RIDGING IS REFLECTED BY 20-40 METER 500 MB HEIGHT
RISES AT 00Z ACROSS THE CENTRAL AND SOUTHERN PLAINS...AND EXTENDING
AS FAR EAST AS THE CAROLINA COASTS. THIS BLOCKING RIDGE PATTERN TO
THE NORTH OF DEBBY IS EXPECTED TO GRADUALLY TURN THE CYCLONE
WESTWARD ACROSS THE NORTH-CENTRAL GULF OF MEXICO BY 36-48
HOURS...WITH A CONTINUED WESTWARD MOTION ACROSS THE NORTHWESTERN
GULF AFTER THAT.
We're also missing Weather456.
$180 a year.
As do I! I really wish I could afford things such as GR2Analyst, as it would be beneficial for my updates.
Probably cuz they ain't got no confidence in it.
He is resting up for the Fray come Monday
Very good discussion by Stewart. It has both of the prime features I have been referring to, the drift possibility to the NE and the models building the ridge over the top out in time. A bit of a dance in the upper levels to determine which motion prevails ultimately. Either way a hurricane by the looks of things but not as far West as earlier forecasts.
I'm in panama city beach! Leaving for home back in louisiana in the morning :) Leaving just in time..water is off limits here obviously..surf is definitely rougher than normal.
AS FAR EAST AS THE CAROLINA COASTS.
How many coasts does the Carolina have?
: )
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