ATL: DEBBY - Post-Tropical

[Evil Jeremy]

Aric, what are your thoughts on Debby's intensity? Recon found support to raise intensity to 60kts, do you think NHC will go that high at 5?

[Recurve]

Others may have said better, the wind in Tampa Bay area now stronger than through most of the rain. Squally, sky lighter, gusty...brittle ends of oak branches (2-3 foot) coming down in places, nothing worse.
Power flickers, no extended outage except for 2,000 customers to the north (check TB TIMES for latest (http://www.tampabay.com/)

and NWS Ruskin (http://forecast.weather.gov/MapClick.php?CityName=Saint+Petersburg&state=FL&site=TBW&textField1=27.758&textField2=-82.6421&e=0).

Tornado watch continues until evening. Rainfall looks to be up to 6" locally since midnight (personal rain gauge, not official).

She is a big wet mess. Lafayette was complaining about not a cloud, looks like that blob popping up on NOLA radar will bring some precip to SE LA.

[Aric Dunn]

Aric, what are your thoughts on Debby's intensity? Recon found support to raise intensity to 60kts, do you think NHC will go that high at 5?

if they raise it would be probably to 65mph. there is just not convection to mix down the winds to the surface to call it a sustained wind.

[tailgater]

EJ wrote I don't know what you guys are seeing. I see a slow drift east, if not stationary movement. As for "Who cares what the models say"..... well.... forecasters for starters? The models have changed today, and backed off the overall western path. Is it possible that Debby will move west? Of course. Wobble watching doesn't discount the models though. We finally have a consensus.

I still see a slow drift NNE but there are some cirus cloulds blowing to the nw making it very hard to tell exactly which direction if any this thing moving now.

[wxman57]

Convection NNW of the center has dropped off since that recon FL wind of 77 kts. Max winds now look to be around 50kts (58 mph) in that area, maybe even 45kts (50 mph).

[thetruesms]

Just what I said - split the difference and show little movement until the models come into agreement - which they do with time.

But a blend is only appropriate if they share the same . . . eh, let's call it paradigm, for lack of a better term. If models all more or less agree that it will be picked up by a trough or get squashed under a ridge, but differ in the details, then a blend is a good idea. But if you blend one model that goes with a trough pluck and another that goes with a ridge squash, then the result doesn't make any physical sense at all. You're basically guaranteeing you'll never be truly right in an attempt to minimize your error.

[FutureEM]

Now that the convection is dying, will there soon be a new burst?

[Evil Jeremy]

You're basically guaranteeing you'll never be truly right in an attempt to minimize your error.

Is that such a bad thing in a case like this?

[ronjon]

Bay News 9 just said they're closing the Skyway Bridge.

[Dean4Storms]

Nice loop here, clearly looks stationary now or an ever so slight drift north.

http://www.esl.lsu.edu/animate/goes/ind ... channel=lc

[robbielyn]

I don't understand why anyone would rely on a computer model more heavily than real time synoptic data. If you every 6 hours see the conditions doing one thing and u see that an ull is present and changing the game, why would someone just go with the euro because its more reliable? Im a major amateur and I just kept watching visible sat and it clearly showed the ull's influence pushing Debby eastward. Last night when I heard stacy's explanation for the gfs solution, I bought it hook line and sinker cause I knew he knew tons more than me and I have nothing but respect for his and nhc's wisdom. I wake up this a.m. And find that ull still keeping debby eastward. So my ? Is: wouldn't it be better to use models in conjunction with real time synoptic data rather than the other way around? Since they tweaked the gfs, maybe that is now the more reliable model. That should have gotten more creedence than it got. I don't think this would hv been so hard to forecast if all they had was visble satellite. While I respect the need for models I do think they can get in the way of the obvious d/t putting them above everything else.

Ps: I'm not bashing nhc they do do an awesome job I'm just wondering if they relied more heavily on conditions vs. Models instead of vice versa thats all.

I think you've made some good points, robbielyn. I mentioned earlier that it would have been wise just to stall the system south of La in the first advisory and admit the uncertainty. Sometimes, I think the 5-day track forces some decisions that might not have been made. More than anything, I think the NHC needs to make sure they have consensus from both the euro and GFS in the future before committing to a determined track.

So what do you do if they do not agree...issue no forecast?

They should have gone with the synoptic forecast of seeing the ull pushing Debby east and that ull was blocking her from going west as well as keeping her weak and sheared which euro didn't support. So with the evidence I would have go with the model that supported the data.

[tolakram]

You're basically guaranteeing you'll never be truly right in an attempt to minimize your error.

Is that such a bad thing in a case like this?

What is the goal? Too look good or make the best forecast you can using the tools and experience you have.

[RL3AO]

You're basically guaranteeing you'll never be truly right in an attempt to minimize your error.

Is that such a bad thing in a case like this?

Yes. Them issuing a forecast that can't happen would be a gross error. They're job is to make a good forecast not avoid making a bad one.

[bamajammer4eva]

AccuWeather.com ‏@breakingweather
Evacuations are underway along Fla.'s west coast in Pinellas County, according to the Pinellas Co. police scanner.

[HurricaneBelle]

NHC 5PM forecast now takes it due north (and extends the TS watch south through the Tampa Bay area to Englewood):

FORECAST VALID 25/0600Z 28.7N 85.5W
MAX WIND 50 KT...GUSTS 60 KT.
50 KT... 25NE 25SE 0SW 25NW.
34 KT...175NE 150SE 40SW 100NW.

FORECAST VALID 25/1800Z 29.0N 85.5W
MAX WIND 50 KT...GUSTS 60 KT.
50 KT... 25NE 25SE 0SW 20NW.
34 KT...150NE 150SE 40SW 100NW.

FORECAST VALID 26/0600Z 29.0N 85.5W
MAX WIND 55 KT...GUSTS 65 KT.
50 KT... 25NE 25SE 0SW 25NW.
34 KT...150NE 150SE 40SW 100NW.

FORECAST VALID 26/1800Z 29.0N 85.5W
MAX WIND 60 KT...GUSTS 75 KT.
50 KT... 25NE 25SE 0SW 25NW.
34 KT...120NE 120SE 40SW 75NW.

FORECAST VALID 27/1800Z 29.5N 85.5W
MAX WIND 60 KT...GUSTS 75 KT.
50 KT... 25NE 25SE 0SW 25NW.
34 KT...120NE 120SE 40SW 90NW.

EXTENDED OUTLOOK. NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 175 NM
ON DAY 4 AND 225 NM ON DAY 5...AND FOR INTENSITY NEAR 20 KT EACH DAY

OUTLOOK VALID 28/1800Z 30.0N 85.5W
MAX WIND 40 KT...GUSTS 50 KT.

OUTLOOK VALID 29/1800Z 30.5N 85.5W...INLAND
MAX WIND 30 KT...GUSTS 40 KT.

[ronjon]

Nice loop here, clearly looks stationary now or an ever so slight drift north.

http://www.esl.lsu.edu/animate/goes/ind ... channel=lc

Nice Loop Dean - boy look at the inflow plume all the way down to the BOC.

[cycloneye]

WTNT34 KNHC 242034
TCPAT4

BULLETIN
TROPICAL STORM DEBBY ADVISORY NUMBER 6
NWS NATIONAL HURRICANE CENTER MIAMI FL AL042012
400 PM CDT SUN JUN 24 2012

...THREAT TO LOUISIANA LESSENS...TROPICAL STORM WARNINGS
DISCONTINUED...


SUMMARY OF 400 PM CDT...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...28.4N 85.8W
ABOUT 205 MI...330 KM ESE OF THE MOUTH OF THE MISSISSIPPI RIVER
ABOUT 100 MI...165 KM SSW OF APALACHICOLA FLORIDA
MAXIMUM SUSTAINED WINDS...60 MPH...95 KM/H
PRESENT MOVEMENT...NE OR 40 DEGREES AT 3 MPH...6 KM/H
MINIMUM CENTRAL PRESSURE...993 MB...29.32 INCHES


WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY...

THE TROPICAL STORM WATCH HAS BEEN EXTENDED SOUTHWARD ALONG THE WEST
COAST OF FLORIDA TO ENGLEWOOD.

THE TROPICAL STORM WARNING FROM THE MOUTH OF THE PEARL RIVER
WESTWARD TO MORGAN CITY HAS BEEN DISCONTINUED.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT...

A TROPICAL STORM WARNING IS IN EFFECT FOR...
* THE MISSISSIPPI-ALABAMA BORDER EASTWARD TO THE SUWANNEE RIVER
RIVER FLORIDA

A TROPICAL STORM WATCH IS IN EFFECT FOR...
* SOUTH OF THE SUWANNEE RIVER TO ENGLEWOOD FLORIDA

A TROPICAL STORM WATCH MEANS THAT TROPICAL STORM CONDITIONS ARE
POSSIBLE WITHIN THE WATCH AREA...IN THIS CASE LATER TODAY.

FOR STORM INFORMATION SPECIFIC TO YOUR AREA...INCLUDING POSSIBLE
INLAND WATCHES AND WARNINGS...PLEASE MONITOR PRODUCTS ISSUED BY
YOUR LOCAL NATIONAL WEATHER SERVICE FORECAST OFFICE.


DISCUSSION AND 48-HOUR OUTLOOK
------------------------------
AT 400 PM CDT...2100 UTC...THE CENTER OF TROPICAL STORM DEBBY WAS
LOCATED NEAR LATITUDE 28.4 NORTH...LONGITUDE 85.8 WEST. DEBBY IS
MOVING TOWARD THE NORTHEAST NEAR 3 MPH...6 KM/H. NO SIGNIFICANT
MOTION IS EXPECTED DURING THE COUPLE OF DAYS...BUT THIS FORECAST
CONTINUES TO BE UNCERTAIN.

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.

ESTIMATED MINIMUM CENTRAL PRESSURE IS 993 MB...29.32 INCHES.


HAZARDS AFFECTING LAND
----------------------
WIND...TROPICAL STORM CONDITIONS ARE ALREADY NEAR OR OVER PORTIONS
OF THE NORTHEAST GULF COAST AND ARE EXPECTED TO REACH THE REMAINDER
OF THE WARNING AREA BY TONIGHT...MAKING OUTSIDE PREPARATIONS
DIFFICULT OR DANGEROUS.

STORM SURGE...THE COMBINATION OF A STORM SURGE AND THE TIDE WILL
CAUSE NORMALLY DRY AREAS NEAR THE COAST TO BE FLOODED BY RISING
WATERS. THE WATER COULD REACH THE FOLLOWING DEPTHS ABOVE GROUND AT
THE TIMES OF HIGH TIDE OVER THE NEXT FEW DAYS...

APALACHEE BAY...4 TO 6 FT
FLORIDA WEST COAST SOUTH OF APALACHEE BAY...2 TO 4 FT
COASTAL MISSISSIPPI EASTWARD TO APALACHEE BAY...2 TO 4 FT
SOUTHEASTERN LOUISIANA...1 TO 3 FT

THE DEEPEST WATER WILL OCCUR ALONG THE IMMEDIATE COAST IN AREAS OF
ONSHORE FLOW. SURGE-RELATED FLOODING DEPENDS ON THE RELATIVE
TIMING OF THE SURGE AND THE TIDAL CYCLE...AND CAN VARY GREATLY OVER
SHORT DISTANCES. FOR INFORMATION SPECIFIC TO YOUR AREA...PLEASE
SEE PRODUCTS ISSUED BY YOUR LOCAL NATIONAL WEATHER SERVICE OFFICE.

RAINFALL...DEBBY IS EXPECTED TO PRODUCE TOTAL RAIN ACCUMULATIONS OF
5 TO 10 INCHES OVER MUCH OF THE FLORIDA PANHANDLE...NORTHERN
FLORIDA...CENTRAL FLORIDA AND SOUTHEASTERN GEORGIA...WITH ISOLATED
MAXIMUM AMOUNTS OF 15 TO 20 INCHES POSSIBLE. GIVEN THE RECENT HEAVY
RAINFALL AND WET SOIL CONDITIONS...THESE ADDITIONAL AMOUNTS WILL
EXACERBATE THE FLOODING THREAT ACROSS PORTIONS OF NORTHERN FLORIDA
AND SOUTHERN ALABAMA.

TOTAL RAIN ACCUMULATIONS OF 2 TO 4 INCHES ARE EXPECTED OVER COASTAL
ALABAMA...MISSISSIPPI...SOUTHEASTERN LOUISIANA AND SOUTH FLORIDA...
WITH ISOLATED MAXIMUM AMOUNTS OF 6 INCHES POSSIBLE.

TORNADOES...A FEW ARE POSSIBLE OVER WEST AND CENTRAL FLORIDA
PENINSULA TONIGHT

NEXT ADVISORY
-------------
NEXT INTERMEDIATE ADVISORY...700 PM CDT.
NEXT COMPLETE ADVISORY...1000 PM CDT.

$$
FORECASTER WTNT44 KNHC 242034
TCDAT4

FORECASTER AVILA


TROPICAL STORM DEBBY DISCUSSION NUMBER 6
NWS NATIONAL HURRICANE CENTER MIAMI FL AL042012
400 PM CDT SUN JUN 24 2012

THERE HAS BEEN A SIGNIFICANT CHANGE IN THE FORECAST TRACK WITH THIS
ADVISORY. THE OFFICIAL FORECAST NO LONGER BRINGS DEBBY WESTWARD
ALONG THE NORTHERN GULF OF MEXICO AND INSTEAD KEEPS THE CYCLONE
MEANDERING OVER THE NORTHEASTERN GULF FOR THE NEXT 3 TO 4 DAYS.
THIS FORECAST IS A COMPROMISE BETWEEN THE CONSISTENT EASTWARD
SOLUTION PROVIDED BY THE GFS FOR THE PAST SEVERAL DAYS AND THE NEW
TWIST OF THE ECMWF. THE ECMWF MODEL...WHICH HAS BEEN
FORECASTING DEBBY TO MOVE WESTWARD ALONG THE GULF OF MEXICO... NOW
HAS THE CYCLONE MEANDERING FOR THE NEXT 3 DAYS OVER THE
NORTHEASTERN GULF. SINCE THESE TWO RELIABLE MODELS ARE IN
MARGINALLY BETTER AGREEMENT...I AM A LITTLE MORE CONFIDENT...BUT
NOT COMPLETELY...THAT DEBBY IS NOT GOING TO TURN WESTWARD OVER THE
GULF. HOWEVER...NEW OFFICIAL TRACK REMAINS A LOW-CONFIDENCE
FORECAST.

DEBBY IS A SPRAWLING SYSTEM...WITH MOST OF THE THUNDERSTORM ACTIVITY
IN A CURVED BAND WELL REMOVED FROM THE CENTER. DATA FROM THE
RECONNAISSANCE PLANE A FEW HOURS AGO INDICATE THAT THE INITIAL
INTENSITY REMAINS 50 KNOTS. THE SHEAR IS NOT EXPECTED TO CHANGE
MUCH FOR THE NEXT DAY OR SO...BUT BECAUSE DEBBY IS FORECAST TO
REMAIN OVER WATER...THERE WILL BE SOME OPPORTUNITY FOR A SLIGHT
STRENGTHENING BEFORE THE CENTER MOVES INLAND. HOWEVER...THE CYCLONE
WILL LOCATED BE NORTH OF THE AREA OF HIGH OCEANIC HEAT CONTENT AND
THE UPWELLING COULD HALT THE INTENSIFICATION.


FORECAST POSITIONS AND MAX WINDS

INIT 24/2100Z 28.4N 85.8W 50 KT 60 MPH
12H 25/0600Z 28.7N 85.5W 50 KT 60 MPH
24H 25/1800Z 29.0N 85.5W 50 KT 60 MPH
36H 26/0600Z 29.0N 85.5W 55 KT 65 MPH
48H 26/1800Z 29.0N 85.5W 60 KT 70 MPH
72H 27/1800Z 29.5N 85.5W 60 KT 70 MPH
96H 28/1800Z 30.0N 85.5W 40 KT 45 MPH
120H 29/1800Z 30.5N 85.5W 30 KT 35 MPH...INLAND

$$
FORECASTER AVILA

[cycloneye]

TROPICAL STORM DEBBY ADVISORY NUMBER 6
NWS NATIONAL HURRICANE CENTER MIAMI FL AL042012
400 PM CDT SUN JUN 24 2012

...THREAT TO LOUISIANA LESSENS...TROPICAL STORM WARNINGS
DISCONTINUED...


SUMMARY OF 400 PM CDT...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...28.4N 85.8W
ABOUT 205 MI...330 KM ESE OF THE MOUTH OF THE MISSISSIPPI RIVER
ABOUT 100 MI...165 KM SSW OF APALACHICOLA FLORIDA
MAXIMUM SUSTAINED WINDS...60 MPH...95 KM/H
PRESENT MOVEMENT...NE OR 40 DEGREES AT 3 MPH...6 KM/H
MINIMUM CENTRAL PRESSURE...993 MB...29.32 INCHES

[Aric Dunn]

interesting. the gulf loop is quite a bit farther north than normal maybe there wont be as much cooling.

http://www.opc.ncep.noaa.gov/Loops/NCOM ... lash.shtml

http://www.opc.ncep.noaa.gov/Loops/NCOM ... lash.shtml

[Evil Jeremy]

This is the biggest change I have ever seen in a single advisory track.