WPC Met Watch


WPC Met Watch

 

Mesoscale Precipitation Discussion: #0257 (Issued at 754 AM EDT Sun May 12 2024
) MPD Selection

 


Graphic for MPD #0257


Mesoscale Precipitation Discussion 0257
NWS Weather Prediction Center College Park MD
754 AM EDT Sun May 12 2024

Areas affected...Central Texas east to the Piney Woods

Concerning...Heavy rainfall...Flash flooding likely

Valid 121152Z - 121752Z

SUMMARY...Localized Flash flooding likely this morning from
central Texas through the Heart of Texas into the Piney Woods as
scattered heavy thunderstorms shift east along a low level
boundary.

DISCUSSION...Radar imagery at 1145Z showed a cluster of elevated
heavy thunderstorms over the Central Texas Hill Country west of
Waco with recent activity developing near/southeast of Waco. This
activity has been moving ENE as 35kt SWly deep layer mean flow is
counteracted by Wly upwind propagation vectors. Hourly rainfall of
2" has been estimated from KSJT and KGRK.

This elevated activity is rooted in the 850-700mb layer above an
inversion north of a warm front over south Texas with about 15000
J/kg of MUCAPE available. Upper level SWly flow is from a
positively-tilted trough over CO/NM that is advecting Pacific
moisture in across Mexico while low level flow over the warm front
is bringing moist flow from the western Gulf of Mexico with PWs
around 1.7" which is 2 sigma above normal.

Guidance is generally too slow/behind on this activity with recent
HRRRs depicting its typical morning cold/dry bias an unable to
maintain this elevated convection from its warm start. However,
the 00Z ARW2 seems to have a general handle on the situation and
maintains and eastward expansion of of this ongoing activity into
the Piney Woods through the rest of this morning.

1hr FFG is generally 2 to 2.5", but the area downstream of current
activity is right in the axis of extreme rainfall over the past
couple weeks that has caused major to in some places record river
flooding, so this FFG is likely too high. The main limitation is
shear with Wly 0-6km bulk shear values of 50kt which should
maintain a somewhat scattered nature. However, given the
sensitivity of this area, localized flash flooding should be
expected.

This boundary persists today as the warm front approaches from the
south, so further heavy rain and flash flooding threats are
forecast this afternoon across this area.

Jackson

ATTN...WFO...EWX...FWD...HGX...SHV...SJT...

ATTN...RFC...WGRFC...NWC...

LAT...LON   32249727 32129443 31129430 30879588 30979867
            31229947 31899944 32139864

Download in GIS format:    Shapefile
 | KML


Last Updated: 754 AM EDT Sun May 12 2024



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