Graphic for MPD #0848

MESOSCALE PRECIPITATION DISCUSSION 0848
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
927 AM EDT SUN OCT 01 2017

AREAS AFFECTED...EAST-CENTRAL FL

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

VALID 011326Z - 011626Z

SUMMARY...A SHORT TRAINING BAND OF THUNDERSTORMS COULD GROW IN
SIZE/EXPAND OVER THE NEXT FEW HOURS BEFORE LOW-LEVEL CONVERGENCE
WEAKENS.  HOURLY RAIN TOTALS TO 2" WITH LOCAL AMOUNTS TO 4" ARE
POSSIBLE.

DISCUSSION...A SHORT AND NARROW BAND OF SHOWERS AND THUNDERSTORMS
APPEARS STALLED NEAR MELBOURNE FL.  THE SURFACE ANALYSIS REVEALS A
CONVERGENCE ZONE/TROUGH IN ITS VICINITY WHICH EXTENDS ACROSS
CENTRAL FL.  PRECIPITABLE WATER VALUES OF 2-2.2" LIE ACROSS THE
REGION.  THE AREA IS NEAR THE BASE OF A SHORTWAVE ALOFT MOVING
THROUGH THE CAROLINAS, WHICH IS AIDING DIVERGENCE ALOFT.  INFLOW
AT 850 HPA IS CONVERGENT AT 15+ KTS INTO THE REGION PER VAD WIND
PROFILES, WHICH IS IMPORTING ML CAPE VALUES OF 1000-1500 J/KG INTO
THE REGION.  EFFECTIVE BULK SHEAR IS 20-25 KTS PER SPC
MESOANALYSES WHICH IS HELPING TO ORGANIZE THE THUNDERSTORM BAND.

THE 00Z NMMB GUIDANCE APPEARS TO BE MODELING THIS AREA OF
THUNDERSTORMS BEST, WHICH ADVERTISES LOCAL AMOUNTS OF ~4".  WITH
THE ML CAPE VALUES EXPECTED TO REMAIN STATIC THIS PERIOD, THE
QUESTION BECOMES HOW LONG THE BOUNDARY LAYER MOISTURE CONVERGENCE
ACROSS THE REGION REMAINS.  RAP MASS FIELDS HAVE BEEN SHOWING IT
EITHER PULSING OR WEAKENING OVER THE NEXT FEW HOURS, SO USED A
THREE HOUR HORIZON FOR THE MPD.  HOURLY RAIN TOTALS OF 2" WITH
LOCAL AMOUNTS TO 4" APPEAR POSSIBLE.

ROTH

ATTN...WFO...MLB...TBW...

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

LAT...LON   28348059 28038050 27758036 27628047 27708116
            27938151 28208141 28308078


Last Updated: 929 AM EDT SUN OCT 01 2017