Mesoscale Precipitation Discussion 1051...Corrected
NWS Weather Prediction Center College Park MD
135 PM EST Fri Dec 14 2018

Corrected for typo in second paragraph

Areas affected...northern FL into eastern GA

Concerning...Heavy rainfall...Flash flooding possible

Valid 141830Z - 150030Z

Summary...Steady rainfall with embedded rainfall rates over 1
in/hr expected to affect northern FL into eastern GA through 00Z.
3-6 inch rainfall totals can be expected which may lead to
flooding and localized flash flooding.

Discussion...GOES 16 10.3 micron imagery through 18Z showed robust
convection in the eastern Gulf of Mexico with the coldest cloud
tops west of the central and northern FL peninsula, beneath a
broad area of upper diffluence. Blended TPW imagery showed values
ranging from 1.7 to 2.0 inches beneath the southwest to northeast
oriented convective cluster which appeared to be co-located within
an axis of 850 mb confluence.

As southwesterly flow ahead of a large upper low to the west
continues to advect higher low level moisture into northern FL,
MUCAPE values are expected to increase into the 500-1000 J/kg
range, helping to support increased rainfall rates relative to
average rainfall rates over the past few hours. Some of this
influence has already been noted at Cedar Key, FL where a rainfall
rate of 1.19 in/hr was observed through 1815Z. Expect widespread
rates of 0.5+ in/hr to increase across portions of northern FL
into eastern GA through 00Z with rates peaking in the 1-2 in/hr
range where unidirectional southwesterly flow allows training axes
to develop.

While the latitude of heaviest rainfall differs in the most recent
hi-res guidance, there is decent agreement on the short term
forecast with adjustments for observations supporting an axis of
3-6 inches from the Nature Coast into north-central FL and perhaps
eastern GA, with amounts ranging from higher to lower from
southwest to northeast. These rains are likely to cause localized
flooding with possible flash flooding in a few locations.

Otto

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

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

LAT...LON   31708081 31118055 29488113 28038279 28028345
            28878354 29768351 30488303 31658175