MESOSCALE PRECIPITATION DISCUSSION 0600
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
231 PM EDT SUN JUL 30 2017

AREAS AFFECTED...CENTRAL FL

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

VALID 301900Z - 302300Z

SUMMARY...HEAVY RAINFALL IN A TROPICAL AIRMASS FOCUSED IN THE LOW
LEVEL CONVERGENCE AHEAD OF A SLOW MOVING FRONT COULD RESULT IN A
FLASH FLOOD THREAT THROUGH THE LATE AFTERNOON.

DISCUSSION...CONVECTION CONTINUES TO FORM AHEAD OF A LOW LEVEL
CONVERGENT FLOW AHEAD OF A COLD FRONT CROSSING NORTH CENTRAL FL
EARLY THIS AFTERNOON. THERE IS A GENERAL LACK OF
LIGHTNING...ESPECIALLY AHEAD OF THE FRONT ITSELF...WITH THE
EXPERIMENTAL GOES-16 CLEAN IR IMAGES SHOWING THE BEST COOLING TOPS
NEAR KTPA. THIS MAY BE ATTRIBUTED TO THE TROPICAL NATURE OF THE
AIRMASS...AS THE 20/1Z KJAX SOUNDING SHOWED A PRECIPITABLE WATER
VALUE OF 2.60 INCHES...WITH WARM RAIN PROCESSES DOMINATING THE
CONVECTIVE COLUMN.

AS THE CONVECTION CROSSED NORTHERN FL THIS MORNING...THE KJAX
RADAR UNDERESTIMATED THE OBSERVED RAINFALL AMOUNTS BY ABOUT
ONE-HALF...WITH A MAXIMUM OF 7.00 INCHES REPORTED NEAR LAKE CITY.
THE AIRMASS WILL REMAIN VERY MOIST...AS PRECIPITABLE WATER VALUES
HOVER NEAR 2.50 INCHES ALONG AND AHEAD OF THE FRONT. THE AIRMASS
REMAINS MARGINALLY UNSTABLE...BUT SHOULD BE SUFFICIENT TO SUPPORT
CONVECTION THROUGH THE LATE AFTERNOON HOURS.

THE MOST RECENT HRRR INDICATED LOCAL 3.00 TO 5.00 INCH RAINFALL
AMOUNTS THROUGH 23Z...AND THIS WAS ECHOED BY THE 12Z WRF ARW AND
THE 12Z NAM CONUS NEST. BASED ON WHAT OCCURRED ACROSS NORTHERN FL
THIS MORNING...THE HIGH RAINFALL RATES IN THE TROPICAL AIRMASS
SHOULD SUPPORT A FLASH FLOOD THREAT...ESPECIALLY IN URBAN CENTERS.

HAYES

ATTN...WFO...JAX...MFL...MLB...TBW...

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

LAT...LON   29518113 28378067 27688026 26797997 26668012
            26558120 26588197 27058244 27758275 28768253
            29238237 29388193