WPC Met Watch

WPC Met Watch


Mesoscale Precipitation Discussion: #0242 (Issued at 501 PM EDT Wed May 08 2024
) MPD Selection


Graphic for MPD #0242

Mesoscale Precipitation Discussion 0242
NWS Weather Prediction Center College Park MD
501 PM EDT Wed May 08 2024

Areas affected...Northeast OK...Southern MO...Northern AR...

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

Valid 082100Z - 090300Z

SUMMARY...Very strong moisture convergence into an pocket of
enhanced moisture along/northeast of low level wave to allow for
initially slow moving cells capable of 1.5-2"/hr rates.  Spots of
2-3" in 2-3hrs pose possible flash flooding.  As the line evolves
incidents of repeating may occur as line flattens to the mean
steering flow.

DISCUSSION...20z surface analysis denotes a surface low along/just
northeast of the dryline intersection across NE OK with a warm
sector bounded to the north by warm front re-enforced by outflow
in wake of late morning's convective cluster, with a surface
wave/effective TROWAL extending northward across west-central MO. 
GOES-WV and CIRA LPW suggest broad EML has begun to wash over the
area, steepening lapse rates and increasing unstable environment
with 3000+ J/kg of MLCAPE; yet RAP analysis and LPW also denote an
enhanced pocket of moisture through greater depth down-shear of
the wave and with low 70s Tds and total PWATs nearing 1.5", ample
moisture flux should allow for increasingly efficient rainfall

Currently, very strong moisture convergence is analyzed cross SW
MO with surface winds gusting to 15-20kts, though direction is
limited until reaching outflow boundary/frontal zone to the north.
As such, expect increasing convective coverage over the next few
hours.  Rates initially have been should continue to be in the
1.5"/hr range; and given effective bulk shear is allowing for
solid cell rotation, forward progression is initially going to be
slow allow for some duration to allow for stripes of 2"+. 

Additionally, there is solid trends in WV imagery for flattening
west to east cell motions while propagation vectors remain
northeast to suggest cell mergers/repeating may become more
consistent across S MO and perhaps far northern AR. Combined with
rates increasing to 1.75-2"/hr should allow for 2-3" totals in 2-3
hour increments before line starts to propagate east-southeast
into late evening.  This places the area of concern within reach
of exceeding broad 1.5"/hr and 2-2.5"/3hr FFG values.  As such,
scattered incidents of flash flooding are considered possible




LAT...LON   38179086 37788981 36918933 36358972 36079076
            35909217 35679391 35609494 35909570 36489552
            36969480 37919300

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Last Updated: 501 PM EDT Wed May 08 2024

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