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SPC MD 122

MD 0122 CONCERNING FREEZING RAIN FOR PORTIONS OF SOUTH-CENTRAL TEXAS
        
MD 0122 Image

Mesoscale Discussion 0122
NWS Storm Prediction Center Norman OK
0150 AM CST Wed Feb 01 2023

Areas affected...portions of south-central Texas

Concerning...Freezing rain 

Valid 010750Z - 011245Z

SUMMARY...Freezing rain showers with rates in excess of 0.1-0.15
in/hr are ongoing and are likely to continue overnight.

DISCUSSION...As of 0745 UTC, regional radar analysis showed
intensifying freezing rain showers across portions of southern and
central TX. Driven primarily by low and mid-level warm advection,
these showers have intensified over the last 90 minutes coincident
with surface temperatures falling to near or below freezing. Recent
reports of freezing rain in the San Antonio Metro and I-35 corridor
suggest freezing precipitation rates have increased to near 0.1-0.15
in/hr with the more intense showers. While the heaviest
precipitation will be intermittent, additional development farther
southwest, evident from new radar echos and hi-res guidance,
suggests multiple rounds of moderate to locally heavy freezing rain
are likely through early this morning. As additional showers develop
and shift northeastward with time, slightly cooler surface
temperatures in the upper 20s F may favor more efficient ice
accretion and some potential for sleet. With multiple rounds of
moderate to locally heavy winter precipitation expected, there
exists the potential for significant icing impacts along the I-35
corridor in central TX through early this morning.

..Lyons.. 02/01/2023

...Please see www.spc.noaa.gov for graphic product...

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

LAT...LON   29289967 30369924 31239848 31579803 31669754 31299680
            30589630 29949688 29099788 28939862 28989929 29289967 

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SPC MD 121

MD 0121 CONCERNING FREEZING RAIN FOR PORTIONS OF THE TEXAS BIG BEND INTO THE WESTERN HILL COUNTRY
MD 0121 Image


Mesoscale Discussion 0121
NWS Storm Prediction Center Norman OK
1226 AM CST Wed Feb 01 2023

Areas affected...portions of the Texas Big Bend into the western
Hill Country

Concerning...Freezing rain 

Valid 010626Z - 011230Z

SUMMARY...Freezing rain is forecast to gradually intensify overnight
tonight as it slowly spread north and eastward. Freezing rain rates
may approach 0.05-0.1 in/hr, at times, within heavier bands.

DISCUSSION...Over the last couple of hours, regional radar and IR
satellite imagery have shown a gradual intensification of a band of
clouds/light precipitation across portions of the TX Big Bend and
Rio Grand Valley. Associated with increasing ascent ahead of a broad
upper low centered over Baja California, precipitation should
gradually increase in coverage and intensity overnight as the low
shifts eastward. Surface observations across portions of west TX
show surface temperatures in the mid to upper 20s F within the
shallow Arctic airmass. Mid-levels remain somewhat dry as indicated
by the 00z DRT sounding, but subtle surface dewpoint rises over the
last few hours indicate slow saturation of the low and mid-levels is
occurring. As broad ascent continues to intensify ahead of the upper
low, precipitation should gradually spread north and eastward with
rates potentially intensifying to 0.05-0.1 in/hr within banded
structures. 

Hi-res guidance suggests the greatest freezing rain rates will
remain south of I-10 for the next few hours hours where low and
mid-levels are more saturated. Freezing precipitation should
eventually spread north of I-10 and into the western Hill country
between 8-10z. With rates of 0.05-0.1 in/hr possible at times, there
exists the potential for significant icing.

..Lyons.. 02/01/2023

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...EWX...SJT...MAF...

LAT...LON   30440391 31750243 32620135 32940021 32679946 31959909
            31269915 30679957 30060055 29820103 29670155 29730228
            29320272 28870311 28850340 28960383 29040392 29340436
            29440441 30440391 

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