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Area forecast discussion 
National Weather Service Fort Worth Texas
516 PM CST Wednesday Dec 24 2014

Aviation...
shortwave ridging passing overhead should provide generally nice
aviation weather across North Texas for the next 24 hours...as the
system along the central Gulf Coast continues its journey east.
At the surface ... winds are in the process of backing to a
more southerly direction across North Texas as a surface ridge
centered over Mexico also translates east into the Gulf.
So...after winds become southerly around 06z or so tonight...they
should remain as such through the rest of the forecast.
Speeds/however/will be on the increase tomorrow as another storm
system organizes over the southwest Continental U.S....and all a taf sites
should see south winds gusting 25 to 30 kts by middle day and
continuing through the end of the forecast.

30

&&

Previous discussion... /issued 340 PM CST Wednesday Dec 24 2014/
low clouds have cleared most of the area this afternoon with
temperatures near 50 degrees and breezy northwest winds. Changes
are on the way with a considerably warmer Christmas day expected
followed by a colder weekend then much colder air for the
beginning of 2015.

Water vapor imagery shows a strong shortwave moving into the
western U.S. Across northern California this afternoon. This
system will dig into the southwest U.S. On Christmas day. Pressure
falls induced in the Lee of The Rockies will serve to
significantly tighten the pressure gradient across North Texas
tomorrow...resulting in a rather breezy Christmas day. Southwest
winds at 850mb and temperatures warming to +12c will allow highs tomorrow
afternoon to climb into the low/middle 60s areawide. The combination
of warming temperatures along with low humidity and gusty winds
will result in an increased grass fire danger across parts of
North Texas...particularly west of Interstate 35. After coordination
with the Texas Forest service it appears that fine fuel
moisture/soil moisture remains sufficiently high to prevent rapid
grass fire growth...so no red flag warning is anticipated despite
meeting the strict meteorological criteria. Localized grass fires
will be possible through the day.

Low level moisture will begin to surge northward Thursday night
into early Friday across North Texas. Rapid expansion of low
clouds into the area is expected early Friday morning along with
some low chances for rain/showers mainly east of I-35. Rain
chances will spread across the entire area late Friday ahead of a
cold front that is expected to move through by early Saturday
morning. Latest model guidance is in better agreement with the
evolution of the southwest U.S. Trough and generally move it
eastward a little faster through the weekend. This should keep
stronger low level warm advection farther east instead of pulling
it westward across North Texas. That being said...rain chances
appear to be tied more closely with the actual cold front and
should taper off fairly quickly during the day Saturday. The
caveat to this is if the trough digs much farther south late
Saturday night into Sunday...then more moisture could be pulled in
atop a fairly cold airmass resulting in a more prolonged cold rain
event.

The weekend will be rather chilly with highs in the upper 40s both
days and only a slight warmup on Monday as the upper trough pulls
away. Model guidance is in good agreement with bringing a chunk of
Arctic air southward early next week. A 1050mb surface high builds
into Montana by late Monday with the Arctic front spilling
southward into North Texas on Tuesday. Temperatures will be
sharply colder with brisk north winds. This system bears close
watching as it could be favorable for wintry precipitation across
North Texas. With a strong upper trough still to the west through
middle week and the 850mb trough axis close by...there could be good
warm moist advection into North Texas atop a very cold airmass.
This is usually favorable for freezing rain. Right now it looks
like a deeper colder airmass will make it through the area. With
colder temperatures aloft...some sort of mix or transition to
sleet then snow appears more likely. With a deeper colder airmass
in place...moisture quality becomes more of an issue as well. Will
continue to monitor this system closely through the weekend as it
could make a mess of the New Year Holiday.

Dunn

&&




Preliminary point temps/pops...
Dallas-ft. Worth, Texas 35 63 49 64 46 / 0 0 5 10 30
Waco, Texas 32 64 49 65 50 / 0 0 5 10 30
Paris, Texas 32 61 45 59 49 / 0 0 5 20 60
Denton, Texas 32 63 48 61 43 / 0 0 5 10 30
McKinney, Texas 32 62 48 61 46 / 0 0 5 10 30
Dallas, Texas 36 63 50 63 48 / 0 0 5 10 30
Terrell, Texas 33 63 49 63 51 / 0 0 5 10 40
Corsicana, Texas 34 63 50 66 53 / 0 0 5 20 40
Temple, Texas 32 64 49 67 52 / 0 0 5 10 30
Mineral Wells, Texas 31 64 45 64 39 / 0 0 5 5 30

&&

Forward watches/warnings/advisories...
none.

&&

$$

30/75

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