Possible Gulf System next week (Is invest 94L)

[KWT]

Enough being shown by the models to suggest there could well be something developing...whether or not its actually tropical I'm not so sure at least at first but given the expected emergence point, yeah tropical development is certainly possible...

[cycloneye]

Interesting marine discussion by TPC.

http://www.nhc.noaa.gov/archive/text/MI ... 071816.txt

LARGEST CHANGE TO THE MORNING OFFSHORE AND HIGH SEAS PACKAGE
COMES WITH THE SYSTEM EXPECTED TO BE SPAWNED FROM THE DEEP LAYER
TROUGH CURRENTLY OVER THE SOUTHEAST U.S. THE HPC/NHC FORECAST
CALLS FOR A COMPROMISE BETWEEN THE ECMWF AND GFS TRACK WHICH
CARRIES A TUE MORNING LOW POSITION NEAR 29N82W AND BRIEFLY MOVES
IT INTO THE FAR NE GULF BEFORE CARRYING IT INTO THE FLORIDA
PANHANDLE NEAR 30N85W WED MORNING. MANUAL PROGS WERE ADJUSTED
TOWARD THIS THINKING WITH THE WEAK LOW EXPECTED TO DEVELOP OFF
THE COAST OF JACKSONVILLE BY MON MORNING.

[rockyman]

12z Euro back on it--forms a system just south of Tampa on Monday, moves it toward the central Gulf on Wednesday, then north toward SE LA by Thursday...with slow strengthening until landfall:
http://greatlakes.salsite.com/big_ECMWF ... _page.html

[Wx_Warrior]

yep...that's a nice little TS from la-fla next thurs

[rockyman]

the beginning?

[KWT]

Interesting to see the ECM surface pressures suggest a low forms and yet the Vort doesn't even make it into the Gulf:

http://raleighwx.easternuswx.com/models ... SLP120.gif

[rockyman]

I think the Raleighwx site is still showing yesterday's 12z Euro run

[KWT]

Yeah that'd make some sense as the 12z didn't get this far enough south yesterday.

Either way I do think the system that is drapped across the SE os the area that may eventually develop as the energy transfers SE. Maybe like Edouard but with a little longer over water?

[baygirl_1]

My interest is piqued! But, I'm confused a bit by some of the wording in the afternoon's AFDs. Here's Mobile NWS' AFD:

"...MONDAY NIGHT SHOULD SERVE
AS A TRANSITION PERIOD TO A BRIEFLY RELATIVELY DRIER WEATHER PATTERN. NEGATIVE THETA-E ADVECTION IS PROGGED TO DEVELOP OVER THE AREA AS A TROPICAL WAVE MOVES OVER SOUTH FLORIDA. 95/TM&&
.LONG TERM (TUESDAY THROUGH SATURDAY)...AS THE FOREMENTIONED WAVE ENTERS THE EASTERN GULF...RELATIVELY DRIER AIR (PWS AROUND 1.7 INCHES) FROM THE SOUTHEASTERN CONUS WILL BE DRAWN OVER THE AREA AS IT ROTATES AROUND THE INVERTED TROUGH TUESDAY. STILL CANNOT TOTALLY RULE OUT ISOLATED DIURNAL CONVECTION THROUGH TUESDAY NIGHT. AS THE WAVE ENTERS THE CENTRAL GULF WEDNESDAY...RAIN CHANCES WILL GRADUALLY
INCREASE FROM THE SOUTHEAST. THIS FEATURE WILL ALSO OVERSPREAD DEEP TROPICAL MOISTURE (PWS 2.1-2.2 INCHES) OVER THE AREA THURSDAY THOUGH SATURDAY. THIS WILL LEAD TO DIURNAL CONVECTIVE TRENDS DEVELOPING ONCE AGAIN DURING THE LATTER HALF OF NEXT WEEK. 95/TM...

Here's the New Orleans NWS' AFD:

..."UPPER SYSTEM WILL GRADUALLY GET GOING ON TUESDAY OVER THE BAHAMAS AND FLORIDA. THIS WILL BRING AN ONSHORE COMPONENT TO THE WINDS AND POSSIBLY TAKE THE EDGE OFF THE HEAT SOMEWHAT. 35&
.LONG TERM...
MODELS COMING INTO A LITTLE BETTER AGREEMENT ON UPPER LOW SCENARIO FOR MID TO LATE NEXT WEEK...BUT THE DEVIL WILL BE IN THE DETAILS. UPPER SYSTEM WILL BE TRACKING TOWARD SOUTHEAST LOUISIANA ON THURSDAY. GFS SOLUTION IS BEING SLIGHTLY FAVORED BY NHC AND NCEP...AND FORECAST IS PATTERNED THAT DIRECTION. GFS SOLUTION IS WEAKER THAN ECMWF AT THIS TIME. PRECIPITATION CHANCES WILL BE ENHANCED SLIGHTLY ON THURSDAY...AND MAY NEED TO BE RAISED FURTHER IN LATER FORECASTS IF TRENDS CONTINUE. 35

OK… is the “upper low” that the NO NWS mentions the same as the tropical wave the Mobile NWS mentions? If so, huh? Aren’t tropical lows surface lows not upper lows????

[Steve]

>>Either way I do think the system that is drapped across the SE os the area that may eventually develop as the energy transfers SE. Maybe like Edouard but with a little longer over water?

The 12Z GFS showed an evolution where the energy sagged down off the tip of Florida, get sparked by something from its SE and then kicks up to Southeast LA. It didn't show a whole lot at the surface, but you could follow it at most of the other levels (see below).

I'd have to see a few more runs before taking it seriously, though it is of note that most global models are now showing some weak energy in the Gulf in the mid-range. Their ability to sniff that out could become much more important over the next few weeks.

GFS 500mb vort.
http://moe.met.fsu.edu/cgi-bin/gfstc2.c ... =Animation

GFS 850mb vort.
http://moe.met.fsu.edu/cgi-bin/gfstc2.c ... =Animation

GFS 300mb vort.
http://moe.met.fsu.edu/cgi-bin/gfstc2.c ... =Animation

(also of note in those animations is that the next wave off of Africa looks to emerge with a companion ridge a few degrees north. They ride together until the end of the run (middle of the ocean).

[Dean4Storms]

Well there is a mid to upper low and then a surface reflection eventually with the models, so both really.

[srainhoutx]

There is a reflection in the Upper Air charts (200mb/500mb). There has been some question (HPC and various WFO's) as to what level the modeled low would be more dominate. We shall see.

[Ivanhater]

DGEX

[dizzyfish]

hmmm... Gonna assume that this is what you all are talking about.

From the Tampa/Ruskin NWS afternoon discussion:

.LONG TERM (MONDAY NIGHT THROUGH SATURDAY)...
MAIN FEATURE IN THE LONG TERM PERIOD IS THE EVOLUTION OF A
POSSIBLE SURFACE LOW FORMING OVER THE STATE AND PROPAGATING
TOWARDS THE WNW. BOTH GFS AND ECMWF CONTINUE TO DEPICT THIS
FEATURE AS A STACKED LOW (RATHER WEAK AT ~1010MB) BUT PLACEMENT
REMAINS AN ISSUE. GFS NOW HAS THE SFC LOW DEVELOPING OVER THE SW
FL COAST WHILE ECMWF SHOWS THE MID UPPER LEVEL TROUGH DIGGING MUCH
FURTHER NORTH WITH THE SFC LOW OFF THE GA COAST. WITH CONFIDENCE
STILL LOW DUE TO THE MODELS EVOLUTION OF THIS FEATURE...WILL
MAINTAIN A BLEND OF THE GFS AND ECMWF.

http://forecast.weather.gov/product.php ... glossary=1

[BigA]

18z NOGAPS forms a low in the Gulf off Tampa on Monday and moves in inland in the MS/AL area on Wednesday.

[Ivanhater]

[dizzyfish]

That's very interesting. That L is right over my house.

[Vortex]

System is becoming a bit more interesting this evening...Long range radar from Melbourne giving the impression that something may be trying to form ENE of Daytona...


00Z NAM at 18H indicates low pressure forming exactly where radar is suggesting something may take place.


http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_018l.gif

[Dean4Storms]

System is becoming a bit more interesting this evening...Long range radar from Melbourne giving the impression that something may be trying to form ENE of Daytona...


00Z NAM at 18H indicates low pressure forming exactly where radar is suggesting something may take place.


http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_018l.gif

This could get interesting over in the Gulf, Lord knows we have bath water out there.

[Ivanhater]

Wow...I must have missed the 12z Euro