MESOSCALE PRECIPITATION DISCUSSION 0100...CORRECTION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
749 AM EDT TUE APR 04 2017

AREAS AFFECTED...NORTHERN FL PENINSULA

CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE

VALID 041146Z - 041621Z

SUMMARY...CONVECTION CONTINUES ACROSS NORTH FL AND THE NORTHERN FL
PENINSULA.  THROUGH 16Z, HOURLY RAIN RATES TO 2" WITH ADDITIONAL
LOCAL AMOUNTS OF 4-6" COULD LEAD TO FLASH FLOODING.

DISCUSSION...CONVECTION CONTINUES TO FIRE AHEAD OF A WEAKENING
FRONTAL BOUNDARY WITHIN A STRONGLY DIVERGENT AREA ALOFT.  LOWERING
INSTABILITY AROUND JACKSONVILLE HAS LED TO A SOUTHWARD SAG TO THE
COMPLEX TOWARDS THE EAST COAST.  PRECIPITABLE WATER VALUES OF 1.8"
EXIST PER RECENT GPS VALUES.  MUCAPES OF 1000-2000 J/KG AND 40 KTS
OF 0-6 KM OF BULK SHEAR INHABIT THE REGION PER SPC MESOANALYSES. 
CONVERGENT 850 HPA INFLOW OF 25-30 KTS IS SEEN IN REGIONAL VAD
WIND PROFILES.  CLOUD TOP TEMPERATURES HAVE BEEN WAVERING, BUT
RECENT EXPERIMENTAL GOES-R IMAGERY SHOWS SOME RENEWED CLOUD TOP
COOLING AS OF LATE.

THE MESOSCALE GUIDANCE CONTINUES TO STRUGGLE WITH THIS ACTIVITY,
WITH THE WETTER 06Z CANADIAN REGIONAL AND 06Z NAM CONEST DOING THE
BEST SO FAR -- MOST OF THE GUIDANCE APPEARS TO BE TOO CONFINED TO
THE IMMEDIATE WEST COAST.  INSTABILITY CLOSER TO THE GULF COAST IS
NOT EXPECTED TO ERODE MUCH WHILE INSTABILITY CLOSER TO THE EAST
COAST SHOULD, WHICH COULD LEAD TO FURTHER SOUTHWARD PROPAGATION
AND EVENTUALLY A MORE WEST-NORTHWEST/EAST-SOUTHEAST ORIENTATION. 
CONVECTION IS EXPECTED TO SHIFT DOWN TO A BOUNDARY APPARENT IN THE
SURFACE WIND FIELD EXTENDING FROM NEAR CEDAR KEY TOWARDS DAYTONA
BEACH, PARTICULARLY LATE IN THE PERIOD ONCE THE CONVECTION
ATTEMPTS TO BECOME MORE SURFACE-BASED.  WITH THE MAIN SHORTWAVE
LEADING TO THE OVERNIGHT UPTICK IN THE CONVECTION PASSING BY TO
THE NORTH-NORTHEAST, IT MAY TAKE UNTIL 16-17Z BEFORE DIVERGENCE
ALOFT RELAXES PER RAP MASS FIELDS.  UNTIL THEN, HOURLY RAIN RATES
UP TO 2" AND LOCAL AMOUNTS OF 4-6" COULD LEAD TO FLASH FLOODING. 
UNCERTAINTY IN FUTURE EVOLUTION KEEPS THE ASSOCIATED CATEGORY
POSSIBLE.

ROTH

ATTN...WFO...JAX...MLB...TAE...TBW...

ATTN...RFC...SERFC...

LAT...LON   30088369 29958180 28768123 28908254 29468354