691
AWUS01 KWNH 010902
FFGMPD
VAZ000-NCZ000-011500-

Mesoscale Precipitation Discussion 0530
NWS Weather Prediction Center College Park MD
501 AM EDT Mon Jul 01 2024

Areas affected...eastern/coastal NC and surrounding portions of
far southeastern VA

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

Valid 010900Z - 011500Z

Summary...Localized rainfall rates of 1-3"/hr with elements of
training and repeating will support an isolated flash flood risk
(particularly along the coast, where residence time is maximzed).

Discussion...Slow moving showers and thunderstorms are
consolidating early this morning ahead of a sluggish cold front,
producing rainfall rates of 1-3"/hr with elements of repeating and
training. The mesoscale environment is highly supportive of
continued heavy rainfall, particularly given a combination of
strong diffluence aloft (with a large polar jet streak to the
northeast and more subtle subtropical jet streak to the southwest)
and low-level convergence/moisture transport (925-850 mb) running
parallel to the coast (from the southwest). The parameter space is
also impressive, as precipitable water values range from 2.3-2.6
inches (near record levels, per MHX sounding climatology) with ML
CAPE of 500-2000 J/kg. Though shear is a bit lacking (less than 25
kts), new convective development will still result in continued
training/repeating elements with slow steering flow (850-300 mb)
of 10-15 kts.

Hi-res guidance (primarily the 00z HREF) supports the continued
risk of localized flash flooding through 15z, gradually ending
from northwest to southeast with the passage of the cold front.
This progression will confine the highest excessive rainfall risk
to the coastal areas, as indicated by 40-km neighborhood 5"
exceedance probabilities of 10-20% (through 15z, per the HREF).
While the overall coverage of flash flooding is expected to remain
small, isolated/localized instances are judged to be likely (given
observational trends and accompanying guidance).

Churchill

...Please see www.wpc.ncep.noaa.gov for graphic product...

ATTN...WFO...AKQ...ILM...MHX...RAH...

ATTN...RFC...MARFC...SERFC...NWC...

LAT...LON   37067581 36687528 35577518 34977564 34407680
            34057773 34317832 34937883 35777820 36687698