← Previous February 5, 2023 6:23 PM

FOUS30 KWBC 060023

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
723 PM EST Sun Feb 05 2023

Day 1
Valid 16Z Sun Feb 05 2023 - 12Z Mon Feb 06 2023

The probability of rainfall exceeding flash flood guidance is less
than 5 percent.


Day 2
Valid 12Z Mon Feb 06 2023 - 12Z Tue Feb 07 2023

The probability of rainfall exceeding flash flood guidance is less
than 5 percent.


Day 3
Valid 12Z Tue Feb 07 2023 - 12Z Wed Feb 08 2023


Positively titled longwave trough ejecting out of the Four Corners
region Tuesday begins to take on a neutral tilt as it approaches
central Texas while a downstream jet streak over the Ohio Valley
strengthens to near 130 kt by late Tuesday/early
Wednesday...providing the large scale forcing for ascent across
the Arklatex region. The deep layer southerly flow ahead of the
system will bring northward higher moisture characterized by
precipitable water values near 1.5", which is between 2-3 standard
deviations above the climatological mean. Late Tuesday night into
Wednesday morning the strengthening low-level jet (850 mb flow
30-40 kts) and deep layer lift is expected to produce several
clusters of heavy rainfall initially across northeast Texas into
northern Arkansas and far southern Missouri.  The favorable
overlap of greater lift, moisture, and instability (MUCAPE of 1000
J/kg) should produce intense rain rates exceeding 1-2"/hr at times
and a deep layer flow near parallel to storm motions could allow
for training/repeating rounds of heavy rainfall. The 12Z runs of
the ECENS and GEFS members still show decent probabilities for 2"+
totals over the period (with some potential for isolated 3-4 inch
amounts) although there was a shift towards the north and
northeast of their overnight runs. As a result...the Slight Risk
area was expanded and shifted that way in this cycle.  Did not
want to remove too much from the southern end of the previous
position, though, due to the above normal soil moisture in parts
of the area due to recent heavy precipitation. The latest NASA
SPoRT 0-40 cm layer soil moisture percentiles are above 90-95
percent in places and precipitation departures are 300-600 percent
of normal. Given the potential for heavy rainfall over saturated
soils, flash flooding will become a greater concern late Tuesday
night through Wednesday across this region. 


Day 1 threat area: https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt
Day 2 threat area: https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt
Day 3 threat area: https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt