Interesting Miami Discussion

[Ed Mahmoud]

0Z GFS takes a tropical-ish looking inverted trough and moves it into Miami in just under a week.

[TampaFl]

This mornings NWS Tampa now mentions the low in the extended.

000
FXUS62 KTBW 270757
AFDTBW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAMPA BAY RUSKIN FL
357 AM EDT THU MAR 27 2008

LONG TERM (SATURDAY NIGHT - WEDNESDAY)...LITTLE OVERALL CHANGE IN
THE FORECAST FOR THE LONG TERM PERIOD. MODELS ARE IN GENERAL
AGREEMENT THAT SOME MID/UPPER LEVEL RIDGING WILL CONTINUE OVER THE
SOUTHEAST U.S. WITH A WEAK DISTURBANCE MOVING ACROSS THE NORTHERN
GULF ON SUNDAY AND INTO THE BAHAMAS ON MONDAY. MEANWHILE AT THE
SURFACE A WEAKENING COOL FRONT WILL BE MOVING THROUGH THE
SOUTHEAST U.S. AND IT STILL LOOKS LIKE IT WILL WASH OUT OVER SOUTH
GEORGIA/ NORTH FLORIDA WITH ANOTHER AREA OF HIGH PRESSURE BRIDGING
THE BOUNDARY AND INCREASING THE EASTERLY FLOW EARLY NEXT WEEK.
MODELS ARE TRYING TO DEVELOP AN AREA OF LOW PRESSURE IN THE
BAHAMAS OR A LITTLE FURTHER SOUTH DURING THE MIDDLE OF NEXT WEEK
WHICH THEN DRIFTS WEST OR WEST NORTHWEST TOWARD FLORIDA. EXACT
DETAILS AND TIMING OF THIS POTENTIAL SYSTEM REMAIN UNCLEAR SO WILL
CONTINUE WITH SILENT 10 POPS AT THIS TIME AND WAIT TO SEE HOW
THINGS EVOLVE OVER THE NEXT FEW DAYS. TEMPERATURES ARE EXPECTED TO
REMAIN NEAR TO SLIGHTLY ABOVE NORMAL THROUGH THE PERIOD.



SHORT TERM/MARINE....JILLSON
LONG TERM/AVIATION...CLOSE


Thoughts & comments welcomed.

Robert

[NDG]

Miami this morning, though they compare 00z runs, the 06z gfs run came in closer with the euro:



AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MIAMI FL
359 AM EDT THU MAR 27 2008

.DISCUSSION...IN THE SHORT TERM, NOT A LOT TO DISCUSS. ZONAL FLOW
WILL CONTINUE WITH VERY DRY ALOFT AND SFC RIDGE ALONG 31N WHICH
WILL RESULT IN A LIGHT TO MODERATE EAST WIND FLOW. IT IS THE
EXTENDED THAT IS STILL UP IN THE AIR. BOTH THE GFS AND ECMWF WANT
TO DEVELOP A CUT OFF 50H LOW SOMEWHERE NEAR THE S FLA PENINSULA
BUT THEY DIFFER AS TO ITS FUTURE TRACK AND LOCATION. THE ECMWF
DEVELOPS IT CLOSER TO CUBA OR NORTHERN CARIBBEAN BUT NOT THE
MONSTER THAT IT HAD ONCE SHOWN. THE GFS DEVELOPS IT OVER THE
WESTERN BAHAMAS AND THEN DRIFTS IT TOWARDS S FLA BY WEDNESDAY WITH
A SFC LOW MOVING ACROSS THE AREA. UNTIL WE GET CLOSER TO THE EVENT
(IF IT EVEN MATERIALIZES) WILL NOT DEPICT THIS SFC LOW AND JUST
KEEP US UNDER GENERAL EASTERLY FLOW AND HAVE ALSO TAKEN OUT ALL
MENTION OF THUNDER. THERE IS JUST TOO MUCH UNCERTAINTY AT THIS
TIME

[HURRICANELONNY]

I always read the local morning and afternoon scientific forecast. I think they started out with this weekend. Now it's mainly the middle of the week. The models change like the wind. Will see if it happens.

[Evil Jeremy]

CMC, GFS, EURO, and now the NOGAPS are showing something. They are not all showing the same thing, but they are all showing something in that area in the next week or so. This is going to be very interesting.

EDIT: It looks like the Weather Channel is favoring something next week as well, as they are giving high chances of rain for next week.

[boca]

The NWS in Melbourne refer to this as a wave and I wonder if this is the earliest wave to affect Florida ever.Its only March 27th. I guess it also is in the wording too,meaning tropical wave vs just a wave which is not tropical in origin.

MON-WED...DEEP EASTERLY FLOW EARLY IN THE WEEK WITH LESS CERTAINTY
OF SFC FEATURES. GFS CONTINUES TO INDICATE WAVE MOVING ACROSS
BAHAMAS TWD S FL MON NIGHT/TUE WITH ECMWF SHOWING SHEARING FRONTAL
ZONE JUST NORTH OF THE STATE AND MOIST SE FLOW ACROSS AREA. BOTH
GLOBAL DEPICTIONS KEY ON BREAKDOWN OF WEAK UPR RIDGE AND LIKELIHOOD
OF LOWER THAN NORMAL HGHTS DEVELOPING OVER THE REGION AT MIDDLE OF
NEXT WEEK...THIS WOULD POINT TO SEASONALLY HIGHER RAIN CHC SHOULD
IT PAN OUT. FORECAST IN EXTENDED WL REMAIN CONSERVATIVE WITH
PRECIP TIL CONSISTENCY IS IRONED OUT.

[wxman57]

This is not an African Easterly Wave (tropical wave). The GFS indicates a weak frontal boundary east of the Bahamas by next Tue/Wed and a very weak upper-level low near the trailing end of the front. This weak upper low and some low-level vorticity move WSW-W toward Florida next Thu/Fri. Nothing tropical about it.

[Ed Mahmoud]

Earliest annual appearance ever by Weatherman57 on a pseudo-tropical thread on this board?

[wxman57]

Earliest annual appearance ever by Weatherman57 on a pseudo-tropical thread on this board?

Could be.

[RL3AO]

5999 posts for wxman. Do something special.

[Ed Mahmoud]

So, what is the breakdown on tropical cyclones that form from purely extra-tropical sources, like dying frontal boundaries and cut-off lows, versus the ones generated by tropical waves?

I guess that is an Atlantic question.


In the Pacific, how many are Atlantic waves that never developed, how many were dangling on the monsoon trough, and how many, if any, had purely non-tropical origins?


Enquiring minds and all that...

[boca]

It looks like the old front to the east of Florida is starting to move to the west in the last couple of frames.
http://www.ssd.noaa.gov/goes/east/watl/loop-avn.html

In addition the rain chance went up 10% this weekend to 40%.

THERE CONTINUES TO BE MUCH UNCERTAINTY IN THE EXTENDED FORECAST...
AND FOR THIS REASON WILL NOT MAKE ANY MAJOR CHANGES AT THIS
TIME. ALTHOUGH LOW-LEVEL FORCING FROM SATURDAYS SURFACE WAVE WILL
NOT LINGER INTO SUNDAY...IT APPEARS THAT A STRONGER MID-LEVEL
SHORTWAVE TROUGH WILL RESULT IN ANOTHER GOOD COVERAGE OF SHOWERS
THROUGH THE END OF THE WEEKEND. LAPSE RATES ALOFT WILL LIKELY
STEEPEN AS THIS FEATURE APPROACHES...AND ALTHOUGH A MENTION OF
THUNDERSTORMS WILL NOT BE ADDED TO THE SUNDAY FORECAST AT THIS
TIME IT WILL LIKELY NEED TO BE CONSIDERED STRONGLY IN FUTURE
FORECASTS. BEYOND SUNDAY...ALL OF THE GLOBAL MODELS SEEM TO AGREE
THAT THE SUBTROPICAL UPPER RIDGE AXIS WILL BECOME ORIENTED IN A
WSW/ENE FASHION ACROSS FLORIDA AS AN UPPER-LEVEL TROUGH MOVES
ACROSS THE NORTHERN AND CENTRAL PLAINS EARLY NEXT WEEK. HOWEVER...
A WEAKNESS IN THE RIDGE IS FORECAST TO LINGER JUST EAST OF THE
PENINSULA...WITH GUIDANCE CONSISTENT IN DEVELOPING A WEAK UPPER
LOW OUT OF THIS FEATURE BY THE MIDDLE OF NEXT WEEK. THIS UPPER LOW
AND ITS ACCOMPANYING SURFACE WAVE WILL LIKELY RESULT IN INCREASING
SHOWER/THUNDERSTORM CHANCES ONCE AGAIN BY THE END OF THIS FORECAST
PERIOD.

[boca]

Where's ronjon when you need him.He usually has good takes on these types of situations.

[MiamiensisWx]

Where's ronjon when you need him.He usually has good takes on these types of situations.

I think you have already received an answer...

wxman57 wrote: "This is not an African Easterly Wave (tropical wave). The GFS indicates a weak frontal boundary east of the Bahamas by next Tue/Wed and a very weak upper-level low near the trailing end of the front. This weak upper low and some low-level vorticity move WSW-W toward Florida next Thu/Fri. Nothing tropical about it."

It may increase our precip chances, which is sorely needed in the Lake Okeechobee region, but it's not tropical (stated in my post as well).

[boca]

Where's ronjon when you need him.He usually has good takes on these types of situations.

I think you have already received an answer...

wxman57 wrote: "This is not an African Easterly Wave (tropical wave). The GFS indicates a weak frontal boundary east of the Bahamas by next Tue/Wed and a very weak upper-level low near the trailing end of the front. This weak upper low and some low-level vorticity move WSW-W toward Florida next Thu/Fri. Nothing tropical about it."

It may increase our precip chances, which is sorely needed in the Lake Okeechobee region, but it's not tropical (stated in my post as well).

I like to get 2 different perspectives on the situation, I'm well aware that wxman57 answered my post, and by the way I think this was the earliest time I've seen wxman57 post.

[jaxfladude]

http://www.firstcoastnews.com/weather/5dayforecast.aspx
Read the text forecast below the 5-Day Forecast Graphic...

[TampaFl]

NWS Tampa morning AFD still mentions possible low developement:

000
FXUS62 KTBW 280659
AFDTBW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAMPA BAY RUSKIN FL
259 AM EDT FRI MAR 28 2008

..LONG TERM (SUNDAY NIGHT-THURSDAY)...MODELS ARE ONCE AGAIN IN
GENERAL AGREEMENT THAT SOME MID/UPPER LEVEL RIDGING WILL CONTINUE
OVER THE SOUTHEAST U.S. WITH A WEAKNESS DEVELOPING OVER THE
BAHAMAS/CUBA. MEANWHILE AT THE SURFACE...AN AREA OF HIGH PRESSURE
WILL MOVE OFF THE NEW ENGLAND COAST AND WELL OUT INTO THE ATLANTIC
OCEAN...BUT CONTINUE TO RIDGE SOUTHWESTWARD ACROSS THE SOUTHEAST
U.S. AND FLORIDA THROUGH TUESDAY. THEREFORE IT LOOKS LIKE IT
SHOULD REMAIN PARTLY CLOUDY AND MAINLY DRY THROUGH TUESDAY...BUT
COULD SEE AN ISOLATED SHOWER OR TWO EACH AFTERNOON ACROSS THE
SOUTHERN ZONES. WEDNESDAY INTO THURSDAY IS WHEN THE UNCERTAINTY
COMES INTO THE FORECAST WITH MODELS DEVELOPING AN AREA OF LOW
PRESSURE OVER THE BAHAMAS/CUBA WHICH THEN DRIFTS NORTH OR WEST
DEPENDING ON WHICH MODEL YOU LOOK AT. IF IT GOES NORTH THE
FORECAST AREA WILL REMAIN ON THE DRY WESTERN SIDE OF THE SYSTEM...
BUT IF IT DRIFTS WEST THE DEEPER MOISTURE SHOULD SPREAD OVER THE
REGION LEADING TO CLOUDS AND A BETTER CHANCE OF SHOWERS. THERE
WILL ALSO BE ANOTHER WEAKENING COOL FRONT MOVING THROUGH THE
SOUTHEAST U.S. DURING THIS TIME WHICH ADDS TO THE UNCERTAINTY. FOR
NOW WILL LEAVE 20 POPS FOR SOUTHERN AREAS ON WEDNESDAY AND
THURSDAY AND WAIT TO SEE HOW THINGS EVOLVE OVER THE NEXT FEW DAYS.
TEMPERATURES ARE EXPECTED TO REMAIN NEAR TO SLIGHTLY ABOVE NORMAL
THROUGH THE PERIOD.


SHORT TERM/MARINE...24
LONG TERM/AVIATION...69

[HURRICANELONNY]

The local forecast is like a hurricane forecast. Changes with every run. The miami forecast last night was mainly a wash out for Saturday and showers/thunder Sunday. Now maybe a shower Saturday with a better chance Sunday. Usually a nice weekend when the GFS calls for rain.

http://www.wunderground.com/DisplayDisc ... Lauderdale

[Patrick99]

Why not? It's about that time when we can start scanning for marginal hybrid development. Even an extremely, extremely weak low moving west through the FL Straits would be interesting, if only because March weather in Florida is so typically boring (last weekend's storms aside)

[MiamiensisWx]

The latest GFS has been trending toward a more realistic (weaker) solution, with an open trough (nearly closed low) moving slowly west toward the FL peninsula. The 850 mb rotation is more pronounced than previous runs, which may signal a stronger surface reflection. It also develops the possible system further south along the southern Cuban coast on Tuesday. Overall, it looks like the run may be slowly transitioning toward a low at the surface, which would present greater chances of hybrid development. Shear does look strong as a shortwave bypasses the possible system, so it seems like development (if any) will be halted. Regardless, the presence of a strong surface ridge, some baroclinic support, and the lack of association with surface fronts does signal some slight positives for development over the Gulf Stream and Bahamas.

500 mb:

http://www.nco.ncep.noaa.gov/pmb/nwpara/analysis/namer/gfs/06/images/gfs_500_120l.gif

MSLP:

http://www.nco.ncep.noaa.gov/pmb/nwpara/analysis/namer/gfs/06/images/gfs_ten_120l.gif