Re: Pattern Change
Posted by Skip Wiley on 9/27/2010, 8:51 pm
In the local media, just enough hype to get more viewers.  

NWS Miami will issue a flood watch tomorrow morning.  Their discussion is very interesting..

DISCUSSION...MAIN FOCUS OF THE FORECAST CONTINUES TO BE ON THE
DEVELOPING WEATHER SITUATION EXPECTED TO UNFOLD TUE-WED WITH THE
MAIN IMPACT EXPECTED TO BE THE POTENTIAL FOR FLOODING...POSSIBLY
SIGNIFICANT. LOW PRESSURE OVER THE WESTERN CARIBBEAN WILL MOVE
TOWARDS WESTERN CUBA TUESDAY...THEN ACROSS SOUTH FL ON WEDNESDAY.
THERE IS THE POTENTIAL FOR THE LOW TO DEVELOP INTO A TROPICAL
CYCLONE...THOUGH INDICATIONS ARE THAT ANY DEVELOPMENT WOULD BE
SLOW TO OCCUR.

REGARDLESS OF TC DEVELOPMENT...COPIUS TROPICAL MOISTURE WILL SURGE
NORTHWARD INTO THE SERVICE AREA TONIGHT-TUE...REMAINING IN PLACE
ON WED AS THE LOW MOVES ACROSS THE AREA. THE DEEP MOISTURE WILL
LIKELY MOVE TO OUR EAST BY THU. IN THE MEANTIME...CIRA
PRECIPITABLE WATER PRODUCT SHOWS PW`S NEARING THE 3 INCH MARK OVER
THE WESTERN CARIB! WATER VAPOR IMAGERY SHOWS A MID/UPPER LEVEL
TROUGH/CUT OFF LOW DIVING INTO DIXIE. THIS WILL FORCE THE
CARIBBEAN MOISTURE N-NE INTO THE AREA. FORECAST SOUNDINGS FROM
BOTH THE GFS AND NAM CONTINUE TO SHOW PW`S APPROACHING MAX
HISTORICAL VALUES HERE BY WED MORNING (NEAR 2.9")...AND WITH THE
CONVERGENCE ASSOCIATED WITH THE APPROACH OF THE LOW...THERE IS AN
INCREASING POTENTIAL FOR HEAVY TO EXCESSIVE RAINFALL ACROSS SOUTH
FL. OF COURSE...SHOULD THE LOW MOVE FURTHER TO THE EAST...THE
HEAVY RAIN THREAT WOULD BE MUCH LOWER. HOWEVER...MODEL CONSISTENCY
OVER THE PAST WEEK PUTS THIS POSSIBILITY AT VERY LOW.

GFS/NAM/ECMWF ALL CONTINUE TO SHOW THE HEAVIEST RAIN OCCURRING
ALONG THE SE FL COAST. INTERESTING TO SEE THAT THE GFS AND NAM
BOTH SHOW WHAT WOULD BE A SIGNIFICANT RAINBAND MOVING NORTHWARD
ALONG OUR SE COAST TUE NIGHT-WED AFTERNOON. WILL NEED TO WATCH
THIS AS RAINFALL RATES COULD BE 2-4"/HR GIVEN THE WARM, EXTREMELY
MOIST ATMOSPHERIC PROFILE EXPECTED. A HYDROLOGIC OUTLOOK WAS
ISSUED FOR ALL OF MAINLAND SOUTH FL EARLIER TODAY...TO HIGHLIGHT
THE HEAVY RAIN/FLOOD POTENTIAL. ALTHOUGH THE OUTLOOK COVERS ALL OF
SOUTH FL...INCLUDING THE GREATER NAPLES AREA...THE GREATEST
POTENTIAL FOR HEAVY RAIN DOES APPEAR TO BE ACROSS THE EAST COAST
METROPOLITAN AREAS TUE NIGHT-WED. THE LATEST HPC QPF RAINFALL FCST
REFLECTS THIS THINKING...SHOWING AREAL AVG RAIN AMOUNTS OF 2-3"
GULF COAST TO 4-6" ATLANTIC COAST. A WESTWARD SHIFT IN THE LOW
WOULD RESULT IN HEAVIER RAINS BEING POSSIBLE TOWARDS THE GULF
COAST. A FLOOD WATCH MAY BE REQUIRED FOR ALL OR PARTS OF THE AREA
IN LATER FCST ISSUANCES...SO STAY TUNED.

THERE IS MODEL CONSENSUS THAT THE LOW WILL PULL NORTHEAST OF THE
AREA ON THURSDAY AS THE MID/UPPER TROUGH PICKS IT UP. MUCH DRIER
AIR LOOKS TO SWEEP INTO THE AREA BEHIND THE LOW THU-FRI...WITH
GFS SHOWING PW`S FALLING TO <1.5".

THERE IS AN EXTREME DEGREE OF UNCERTAINTY FOR THE FAR EXTENDED
FCST...DURING THE UPCOMING WEEKEND AND BEYOND. THE LATEST 12Z RUN
OF THE GFS SHOWS A TROPICAL CYCLONE DEVELOPING IN THE NW CARIB
FRI...MOVING NORTHWARD INTO THE STRAITS/FAR SE GULF SUN-EARLY NEXT
WEEK. THIS SOLUTION WOULD NOT BE GOOD. HOWEVER...THE ECMWF SHOWS
A STRONGER MID/UPPER LEVEL TROUGH OVER THE EASTERN SEA
BOARD...KEEPING THE MORE PRONOUNCED TROUGHING AND WEAKER LOWS
FORMING WELL TO OUR SOUTHEAST THROUGH NEXT WEEK WITH THE AREA
MOSTLY DRY - TWO COMPLETELY DIFFERENT SCENARIOS. IMPOSSIBLE TO
DETERMINE WHICH ONE LEANS MORE TOWARDS REALITY SO HAVE MADE NO
CHANGES TO THE EXTENDED FORECAST. /GREGORIA

98
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Pattern Change - BobbiStorm, 9/27/2010, 9:56 am
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