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Area forecast discussion 
National Weather Service Corpus Christi Texas
1243 PM CDT Tuesday Sep 30 2014

Discussion...updated for 18z aviation.

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Aviation...some low ceilings have been occurring across the area this
morning...but starting to see that all lift out to MVFR
conditions. Expect mainly MVFR through the rest of the afternoon.
Could see a few showers for eastern taf sites this afternoon...but
so far precipitation mainly staying offshore. The weak trough axis is
moving inland though which could lead to some convection
developing this afternoon. Tonight expect for to redevelop given
the abundant surface moisture and anticipated drying above the
boundary layer. Could see IFR to LIFR conditions for vct...and
MVFR to IFR elsewhere. Conditions improve by middle morning
Wednesday.

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Previous discussion... /issued 436 am CDT Tuesday Sep 30 2014/

Short term (today through wednesday)...patchy fog early this
morning will dissipate drg the 12-14z period. GFS/ECMWF/NAM
deterministic forecast a series of disturances to move across the northern
Continental U.S. Drg the period yet with limiting upper forcing over the
cwa/msa. Msas reveals a weak surface trough near the coast which the
GFS forecasts to move westward today before dissipating. GOES sounder
depict precipitable water values near/above normal values near the coast and
offshore. The combination of moisture/surface trough suggest at least
isolated convection mainly over the eastern County Warning Area/msa today (the sref quantitative precipitation forecast
probability output adds credence to such.) Lower precipitable water values are
expected over the region tonight/Wednesday and thus no precipitation is
expected except over the offshore coastal waters where moisture may be
sufficient. Anticipate at least patchy fog over the County Warning Area drg the
09-14z Wednesday period (consistent with sref visibility
probability output/NAM soundings at select locations) with the
best chance over the western County Warning Area (strong decoupling in the vertical
west/much weaker east.) Added patchy fog to the inland County Warning Area for the
09-14z Wednesday period. Cbi neural network water level predictions at
select tcoon sites suggest levels below 2ft mean sea level drg high tide
today and thus do not anticipate minor tidal overflow.

Long term (wednesday night through monday)...models continue to
show a gradual increase in low level moisture into S Texas Wednesday
night/Thursday in response to a deepening low pressure system moving
into the plains. Kept a slight chance across the eastern portions of
the County Warning Area on Thursday but very warm middle level temperatures will keep activity to
a minimum. Moisture continues to increase Thursday evening ahead of a
cold front. Models have been fairly consistent with the front
moving into S Texas sometime Thursday night/Friday timeframe. The Canadian
and GFS solutions are the fastest with the boundary reaching the coastline
around 12z Friday. The European model (ecmwf) is just a tad slower and weaker and the
NAM is the slowest with the boundary just entering the northern County Warning Area around
12z Friday. Have leaned toward the faster solutions. Regardless...they
all show convection developing along the boundary as it moves southward
across the County Warning Area Thursday night. Have lowered probability of precipitation for the 00z-06z Thursday
evening timeframe then bumped probability of precipitation up from 06-12z Friday morning
timeframe. Although the main core of the upper jet is forecasted to
remain far north of the County Warning Area...the tail end could provide some upper
level energy along with diffluent flow aloft. Models also show
moderate instability/lift/convergence ahead and along the boundary.
These combined features could lead to strong storms...possibly
isolated severe storms. Think the better chance for severe will be farther north
closer to the upper jet dynamics...but can not rule it out this
far S. Heavy rain will also be a concern due to the abundant rain
some areas have already received. Although models suggest this
system should move fairly quickly through the area resulting in
less rainfall. Still some uncertainty with model solutions with regard
to timing and strength so will hold off mentioning severe or flood
issues just yet. There remains some inconsistencies with how fast
things dry out across S Texas as well. Have leaned to the faster
model solutions with respect to the drier airmass filtering into S Texas
and ending the precipitation from north to S through Friday afternoon. Generally
dry conditions then persist through the weekend with moisture
gradually returning through the first part of next week. Made only
minor tweaks to the temperatures which are forecast to be slightly above normal
ahead of the front. Kept temperatures below guidance behind the front through
the weekend with a gradual warming trend into next week. Kept
winds below advisory criteria over the waters but this may need to
be adjusted.

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Preliminary point temps/pops...
Corpus Christi 75 89 76 90 75 / 10 10 10 20 50
Victoria 74 90 76 92 72 / 10 10 10 20 50
Laredo 75 95 78 98 77 / 10 10 10 10 50
Alice 73 92 76 93 75 / 10 10 10 20 50
Rockport 78 87 78 90 75 / 10 10 10 20 50
Cotulla 72 93 75 96 72 / 10 10 10 10 40
Kingsville 74 91 76 93 76 / 10 10 10 20 40
Navy corpus 78 87 80 90 78 / 10 10 10 20 40

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Crp watches/warnings/advisories...
Texas...none.
GM...none.

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Pz/83...aviation

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