Tropical Storm Debby has formed in the Gulf of Mexico

By: angelafritz , 9:18 PM GMT on June 23, 2012

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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

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Quoting Levi32:


It should take quite a while to erode the ridge to that point. The life cycle of massive Texas ridges is fairly predictable. If Debby moves slower is still over water by late Thursday, a bend towards the northwest could become a possibility.


Hmmm...I was looking at this HPC map forecast...which hints at the ridge (blue H) north of Debby becoming pushed eastward by day 4...as storm system from west coast moves into the picture. Am I interpreting this correctly?
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1235. nigel20
Good evening everyone!

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

Do you guys think that Debby can make to a cat 2?
Member Since: November 6, 2010 Posts: 12 Comments: 8462
Quoting Ameister12:
Anybody with Analyst have some nice color tables they'd like to share? =)

Have you made an account on GRlevelXStuff and looked through the downloads section?
Member Since: Posts: Comments:
If you pay close attention to the total precip animation, you can see partly why Debby is beginning to strengthen now.

The ULL that was sitting over the northwestern GOM is retreating to the SW quite rapidly. This retreat is taking the last of the mid level dry air that was hindering Debby, with it, and high pressure is filling in the gap in the central GOM.

That's my take on what I can see happening.



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Quoting Ameister12:
It's looking more and more likely we may see Debby get over Category 1 intensity.

I just dont think its gonna go that far south anymore
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Quoting tornadodude:


it's a dark and scary world


but quite entertaining :)
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Anybody with Analyst have some nice color tables they'd like to share? =)
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How old are the models on stormpulse they show the storm going more north? are these old models?
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Quoting kmanislander:


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.


Not unexpected, even the west leaning models were saying it might drift N or NE at first, before hooking back west.
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1227. hahaguy
Quoting fortpiercecane1:

Not as bad as it initially looked on radar before arriving.

That is true.
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1226. pottery
Quoting kmanislander:
Early game for me tomorrow so will bid you all a good night. Will catch up on Sunday.

Have a Good One.

I'm out too.
Thanks for the commentary, guys.
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Here's the man of the hour: STACY STEWART!!!
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Obvious center:

Member Since: June 9, 2007 Posts: 4 Comments: 15950
1223. Levi32
Quoting TomTaylor:
I disagree.

The GFS's greatest flaw is not convective feedback, in fact lately I haven't seen it bomb out many storms at all. The real problem shining through is that the GFS likes to overdo the strength of the trough causing it to pull systems out of the tropics faster than other models. In this case it is over doing the trough, making it stronger at the surface and also promoting stronger surface ridging across the East coast, allowing it to spin up a storm.

Look at the 12z Euro vs the 12z GFS at 48hrs. GFS has a stronger trough in the upper levels and at the surface.

(click to enlarge)


Convective feedback doesn't necessarily mean bombing out. If anything it makes the GFS fail to strengthen and consolidate potential TCs. In 48 hours look where all the precipitation is: up by South Carolina, most of it stripped from Debby entirely. This is where the GFS has been trying to develop a secondary low, and why Debby eventually slides northeastward following the feedback. That's the flaw. None of the other models have significant precipitation east of Florida in 48 hours.

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Honestly, even though GR2Analyst costs $250, it is well worth it. GREarth on the other hand, there is no reason for it to cost $180 A YEAR. I mean don't get me wrong, it's a cool product, but you can find basically everything that it is composed off online for free.
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1221. Drakoen
Quoting Levi32:


Well, to be honest, it's just the RAP model being displayed. Graphics can be viewed for free without the fancies.


I noticed that, but I like the product graphics.
Member Since: October 28, 2006 Posts: 57 Comments: 30813
That a 'cane headed this way?

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Quoting hahaguy:
Very heavy rains in Port St. Lucie right now. Luckily not too much thunder or lightning.

Not as bad as it initially looked on radar before arriving.
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Early game for me tomorrow so will bid you all a good night. Will catch up on Sunday.
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NHC SAYS DEBBY WILL BE HURRICANE,2 HURRICANES IN JUNE.........WOOOWW

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Quoting Ameister12:
Every weather geek needs a GRLevelX product. I have GR2Analyst and It's an awesome program!


I have GR2Analyst and GRLevel3, love them both
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Debby could peak at cat 2 I think and the worst is that is a big storm storm surge is going to be a problem.
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1214. Levi32
Quoting NCHurricane2009:


If he mentions the west coast trough...what's the deal with not bending the track more northwestward by 5 days when it appears the west coast trough should begin eroding the ridge? This is what I am expecting...which brings Debby closer to the upper Texas coast.


It should take quite a while to erode the ridge to that point. The life cycle of massive Texas ridges is fairly predictable. If Debby moves slower is still over water by late Thursday, a bend towards the northwest could become a possibility.
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Quoting zoomiami:


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?


Fabulous weather but very windy today due to Debby in the GOM.Lots of kite boarding going on.
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Quoting CybrTeddy:
3172. I disagree, look at the last few GFS runs. See how it develops a seperate low by Florida? None of the models are showing that, and that is why it gets pulled NE - the low by the east coast of Florida that would become ''Ernesto'' in that situation influences it and pulls it into the trough. This is a classic example of the GFS's greatest flaw - convective feedback. All this energy in the Gulf and the GFS doesn't really know what to do with it, so it develops separate lows. This should be discarded IMO from the forecast unless other models start showing a separate low in the Atlantic.
I disagree.

The GFS's greatest flaw is not convective feedback, in fact lately I haven't seen it bomb out many storms at all. The real problem shining through is that the GFS likes to overdo the strength of the trough causing it to pull systems out of the tropics faster than other models. In this case it is over doing the trough, making it stronger at the surface and also promoting stronger surface ridging across the East coast, allowing it to spin up a storm.

Look at the 12z Euro vs the 12z GFS at 48hrs. GFS has a stronger trough in the upper levels and at the surface.

(click to enlarge)
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Quoting StLongoDrew:


WU After Dark


it's a dark and scary world
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Every weather geek needs a GRLevelX product. I have GR2Analyst and It's an awesome program!
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That was a very complete and to the point discussion by Stacey Stewart.
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Quoting mynameispaul:


It's like watching a herd of turtles stampede thru a peanut butter patch.

LOL!!!
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Quoting Levi32:
I love Stewart. He has a reason behind the forecast, not a model consensus, and he mentions the west coast trough I have been speaking about for the last few days.

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.


If he mentions the west coast trough...what's the deal with not bending the track more northwestward by 5 days when it appears the west coast trough should begin eroding the ridge? This is what I am expecting...which brings Debby closer to the upper Texas coast.
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Quoting CaicosRetiredSailor:
...AND EXTENDING
AS FAR EAST AS THE CAROLINA COASTS.


How many coasts does the Carolina have?

: )


I see you
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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
Member Since: Posts: Comments:
1204. Levi32
Quoting Drakoen:


Good job! I need to get my hands on that software.
Quoting CybrTeddy:


As do I! I really wish I could afford things such as GR2Analyst, as it would be beneficial for my updates.


Well, to be honest, it's just the RAP model being displayed. Graphics can be viewed for free without the fancies.
Member Since: Posts: Comments:
1203. Drakoen
Quoting CaicosRetiredSailor:
...AND EXTENDING
AS FAR EAST AS THE CAROLINA COASTS.


How many coasts does the Carolina have?

: )


Ask Press
Member Since: October 28, 2006 Posts: 57 Comments: 30813
1202. Patrap
Hurricane Preparation 2012
Member Since: July 3, 2005 Posts: 428 Comments: 129757
I'm going to torture Kori and not write a blog tonight.
Member Since: Posts: Comments:
Good Night Folks....Will be with Yall tomorrow in the am.
Member Since: Posts: Comments:
...AND EXTENDING
AS FAR EAST AS THE CAROLINA COASTS.


How many coasts does the Carolina have?

: )
Member Since: Posts: Comments:
Quoting Patrap:
We have it on Radar and as it comes north the view will only improve from Mobile, this one(Red Bay) and NOLA.





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.
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Quoting Ameister12:
No surprise here. Stacy Stewart wrote it. =)

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


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.
Member Since: Posts: Comments:
1196. Patrap
Quoting rolltide36526:
Pat may need to have Hugo on ready 1 tomo.


He is resting up for the Fray come Monday

Member Since: July 3, 2005 Posts: 428 Comments: 129757
Pat may need to have Hugo on ready 1 tomo.
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damn lysdexia is a killer.
Member Since: August 23, 2010 Posts: 0 Comments: 1005
It's looking more and more likely we may see Debby get over Category 1 intensity.
Member Since: Posts: Comments:
1166 TropicalAnalystwx13: Why are they withholding the most important forecast product from us?!

Probably cuz they ain't got no confidence in it.
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Quoting Drakoen:


Good job! I need to get my hands on that software.


As do I! I really wish I could afford things such as GR2Analyst, as it would be beneficial for my updates.
Member Since: July 8, 2005 Posts: 259 Comments: 24574
did someone say it's "rumping the pidge"?
Member Since: August 23, 2010 Posts: 0 Comments: 1005
Quoting Drakoen:


Good job! I need to get my hands on that software.

$180 a year.
Member Since: Posts: Comments:
Quoting CybrTeddy:
You know, now that Drak has popped back in, what happened to extreme236? He was a great contributor, I haven't seen him so far this season.

We're also missing Weather456.
Member Since: Posts: Comments:
You know, now that Drak has popped back in, what happened to extreme236? He was a great contributor, I haven't seen him so far this season.
Member Since: July 8, 2005 Posts: 259 Comments: 24574
1186. Patrap
We have it on Radar and as it comes north the view will only improve from Mobile, this one(Red Bay) and NOLA.



Member Since: July 3, 2005 Posts: 428 Comments: 129757

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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

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