Possible Development in the Eastern GOM?

[ronjon]

The latest 12Z NAM develops a low pressure system in the eastern GOM that just sits and spins for several days. The 00Z UKMET and NOGAPs also show weak low pressure forming in the eastern GOM. The CMC and GFS wants to develop the low pressure further east over the FL peninsula. This feature, if it formed, would be off the tail end of a front that was brought down with the latest east coast trough. I haven't checked wind shear lately so that may be a big hinderance to any development. Water temps are plenty warm with 86 deg from the buoy 100 miles west of Bayport, FL.

http://www.nco.ncep.noaa.gov/pmb/nwprod ... loop.shtml

[Cyclone1]

Cool, maybe it'll be something to watch.

[Steve]

That's a pretty odd solution. It basically takes a cutoff styled low and just sits it in the north gulf churning things up. Some of the NAM runs on the B storm this year were money.

Steve

[windstorm99]

NAM model should not be used for the tropics...

[flwxwatcher]

Yes...
I have seen the models hinting at weak low pressure in the Eastern Gulf or over Florida.. The 18Z DGEX is the most bullish with a low in the Eastern Gulf. The DGEX seems to overdo things though IMHO... but we will see in the next couple days :)

[ronjon]

NAM model should not be used for the tropics...

I always hear this statement when the NAM is used. The NAM shouldn't be tossed blindly but should be used in conjunction with the other global models. I agree for the deep tropics with an established cyclone that the NAM is of limited value. However, in situations like this one, with low pressure evolving from the remnants of a frontal trough, it does indeed have some value. In addition, all the global models are showing low pressure developing either over the eastern GOM or over the FL peninsula the next few days, so the NAM is not out on its own. In fact, if you read any of the local NWS forecast discussions, you'll see that about equal weight is placed on the NAM vs the GFS - with the other global models adding in the mix to provide the forecast.

[canetracker]

Looks really similar to the area spinning right now around western Cuba. It has been spinning there for hours. Maybe this is what the NAM is hiniting at?
http://www.meteo.psu.edu/~gadomski/SAT_CARIBWIDE/anim8vis.html

[Tampa Bay Hurricane]

Just bring me some more rain lol...because I can't stand a drought.

[Steve]

I agree with ronjon. The NAM can be useful. It's sometimes pretty good with predicting where concentrated moisture is going to be. I wouldn't put my life on any of its runs, but you can't rule out the value if you understand what it is.

Steve

[Steve]

>>Looks really similar to the area spinning right now around western Cuba.

Not sure. I haven't looked at the upper charts, but that looks like it's above the surface. The spin that run of the NAM shows kind of develops south of the mid-Panhandle.

I'm going to see what's up with any later runs just because there isn't a whole lot to watch. The Gulf (including W Gulf) looks juiced like perhaps it's in a slight mjo phase (haven't looked).

Steve

[Steve]

Okay, the 00z MSLP/500 shows a more organized low pressure (weighted to the east). There's a 576 line under a 1012 upper high. Eh, mildly worth something to keep an eye on.

I guess we'll know by the 7th if these few runs of the NAM were onto something. You never know.

Steve

http://www.nco.ncep.noaa.gov/pmb/nwprod ... loop.shtml

[Meso]

I just saw this too... The Nogaps also picks up on it.
http://moe.met.fsu.edu/tcgengifs/ngp/20 ... /slp21.png

Ukmet also shows a closed low there that doesn't deepen much,but it shows it much sooner.

[Stormavoider]

Tampa radar shows turning centered just NE of Tampa Bay.

[ronjon]

06Z NAM even more agressive than earlier versions with low pressure development in the eastern GOM. The NAM has support from the 00Z runs of the NOGAPs and UKMET, although both of these models show a weaker system. From Tampa radar and SAT, a cc spin is evident just NE of Tampa Bay. Lowest pressure I could find at state reporting stations is 29.98 at both Tampa and Lakeland - which isn't really very low. Is this the feature that the models are keying on? Obviously, for any development, it would have to move offshore. The system off the west coast of Cuba is an ULL that drifted south off the west coast of FL this week.

http://www.nco.ncep.noaa.gov/pmb/nwprod ... loop.shtml

[ronjon]

Interesting discussion from Tampa Bay NWS office this morning. Seems that the Euro is now in the camp of the NAM, UKMET, and NOGAPs. This is increasing my confidence that some sort of low pressure will be forming in the eastern GOM over the next few days.

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAMPA BAY RUSKIN FL
246 AM EDT WED JUL 4 2007

...SOME LOCALLY HEAVY RAINFALL POSSIBLE TODAY AND THURSDAY...

.SHORT TERM (TODAY - FRIDAY)...MODELS CONTINUE TO DIFFER SOME THIS MORNING
WITH REGARDS TO THE HANDLING OF A MID LEVEL LOW AND ATTENDANT WEAK SURFACE LOW ALONG A FRONTAL TROUGH OVER THE SOUTH-CENTRAL PENINSULA EARLY THIS MORNING. MODELS THIS MORNING HAVE SPLIT INTO TWO CAMPS WITH THE NAM AND TO A LESSER EXTENT UKMET/ECMWF TAKING THE LOW SLOWLY WEST OVER THE EAST
CENTRAL GULF THROUGH FRIDAY AS THE SURFACE RIDGE AXIS OVER THE SOUTHEASTERN U.S. DROPS SOUTH TO THE SOUTH CENTRAL PENINSULA IN RESPONSE TO SOME SHORT WAVE ENERGY MOVING SOUTHEAST THROUGH THE BASE OF THE AMPLIFYING LONG WAVE TROUGH OVER THE NORTHEASTERN U.S.. THE GFS ON THE OTHER HAND MEANDERS THE LOW ACROSS THE PENINSULA THROUGH THURSDAY...BEFORE BEING PICKED
UP AND LIFTED OUT TO THE NORTHEAST ON FRIDAY BY THE AFOREMENTIONED SHORT WAVE ENERGY ENERGY PASSING BY TO THE NORTH. GIVEN THESE DIFFERENCES CONFIDENCE IN THE FORECAST REMAINS RATHER LOW TODAY...BUT WITH THE BULK
OF THE MODELS SHOWING SOME SORT OF WEST NORTHWEST MOTION TO THE LOW OVER THE NEXT FEW DAYS...WILL FAVOR A BLEND OF THE UKMET/ECMWF AND A WEAKER TONED DOWN VERSION OF THE NAM DURING THE SHORT TERM PERIOD.

[caneman]

Assuming the Euro and UKMET verify would it then be shunted back NE after Friday?

[wjs3]

Okay, the 00z MSLP/500 shows a more organized low pressure (weighted to the east). There's a 576 line under a 1012 upper high. Eh, mildly worth something to keep an eye on.

I guess we'll know by the 7th if these few runs of the NAM were onto something. You never know.

Steve

http://www.nco.ncep.noaa.gov/pmb/nwprod ... loop.shtml

Just to clarify, that's a 576 thickness (the thickness of the layer between 1000 MB and 500 MB is 576 dekameters--thickness is kind of a surrogate for the temperature in the layer, as you probably know) over a 1) surface (not upper) and 2) low (not high)pressure of 1012.

WJS3

[ronjon]

Assuming the Euro and UKMET verify would it then be shunted back NE after Friday?

Probably. The NAM does show it starting to slowly drift toward the Big Bend late Friday into Saturday (but still over the NE GOM). Depends on the strength of the next trough forecast over the east coast and of course if a low pressure system develops.

[skysummit]

This from NOLA's HWO this morning:

"ONE CONVENTIONAL FORECAST MODEL INDICATES A WEAK AREA OF LOW
PRESSURE POSSIBLY DEVELOPING OVER THE EAST GULF OF MEXICO LATE
FRIDAY AND MEANDERING OVER THE NORTHEAST GULF AND OFF THE MOUTH OF
THE MISSISSIPPI RIVER. THIS REGION OF THE GULF IS A RELATIVELY
WARM POCKET OF WATER. THE OTHER FORECAST MODELS SHOW A LESSER
RESULT. THIS FEATURE WILL BE MONITORED OVER THE NEXT FEW DAYS TO
SEE IF A SURFACE LOW PRESSURE SYSTEM MATERIALIZES AND ASSUMES
TROPICAL CHARACTERISTICS. AT THIS TIME...CONFIDENCE IN THE
SCENARIO IS RATHER LOW."

[ronjon]

Latest 12Z NAM at 84 hrs.

http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_084s.gif