Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Fort Worth Texas
400 am CDT Wednesday Jul 23 2014
early morning water vapor imagery shows a large anticyclone
centered over New Mexico with a TUTT low moving westward across
southern Louisiana. Several weak shortwaves are noted moving
around the periphery of the western ridge into the central U.S.
This morning. Building heat has been the main story for North
Texas over the last couple of days and this will continue into the
weekend with only small chances for rainfall.
Today the TUTT low over Louisiana will continue to move westward
spreading weak ascent across southeast Texas. This should result
in a scattering of afternoon showers and thunderstorms southeast
of the area. Farther north...a weak disturbance will slide
southward through the Ozarks igniting showers and thunderstorms
along a cold front across parts of Arkansas and eastern Oklahoma
this afternoon. These thunderstorms should move from northeast to
southwest given the flow around the periphery of the upper ridge.
The hrrr...RUC...and 4km NAM all indicate the potential for
convection into the evening hours across parts of North Texas so
will have some 20/30 probability of precipitation across the northern half of the County Warning Area. A
few strong storms are possible with gusty winds being the main threat.
By Thursday...the center of the 700mb ridge edges closer to the
area and temperatures should continue to warm by a degree or so.
The cold front that will be over the Ozarks today will continue
southward on Thursday and should be located across the lower
Mississippi River valley by late afternoon. While the front itself
wont really affect North Texas temperatures...scattered
thunderstorms may develop as far west as Canton to Palestine so
will have some 20 probability of precipitation across the far eastern counties.
Friday looks like it will be the warmest of the next several days
with the center of the 700mb ridge nearly overhead. Highs will
range from 100 to 105 across North Texas with heat index values
right near 105. Some relief may be on the way however as a very
strong shortwave will be located across south central Saskatchewan
on Friday. Model guidance is in excellent agreement with the
handling of this feature...digging it into the eastern U.S.
Through the weekend. This will result in a rather large and deep
trough over the eastern U.S. Into early next week with the upper
ridge getting shunted westward. While not as cool as last
week...it does appear that temperatures will cool back to below
normal levels with at least some additional chances for rainfall
by the middle of next week.
Concerning potential heat advisory...heat index values will be
near or slightly above 105 degrees both Thursday afternoon and
again on Friday. A heat advisory will likely be required during
/issued 1145 PM CDT Tuesday Jul 22 2014/
Concerns...potential for thunderstorms late Wednesday.
An upper ridge remains to our west. The dome leans from Colorado
at 20kft to near El Paso at 40kft. Deep northerly flow on the
eastern periphery of the high will help guide a cold front...now
in Kansas...into the Southern Plains on Wednesday. As the boundary
encounters the very unstable maritime tropical air mass across
Oklahoma...thunderstorms will likely develop as early as midday
Wednesday. This shallow boundary should slow its southward
progress during the daylight hours...but the northerly flow
aloft will allow the convection to slowly approach the Red River
late in the day. If these storms are able to invade Texas...it
would be near nightfall. The cells would be far from their initial
forcing mechanism...and with insufficient shear to maintain the
updrafts...the loss of daytime heating should bring them to an
end. Any impacts at metroplex terminals would likely require
initiation much closer to the Red River...if not within Texas...
which would only occur if the frontal boundary is able to slip
much farther south than the current guidance suggests. Based on
the depth of the mild air behind it and the typical evolution of
weak fronts in northerly flow events this time of year...this is
unlikely. At this point...expect impacts will be limited to north
departures and northeast arrivals Wednesday afternoon/evening.
Preliminary point temps/pops...
Dallas-ft. Worth, Texas 98 78 100 79 102 / 10 20 10 10 5
Waco, Texas 98 77 100 78 101 / 10 10 10 10 5
Paris, Texas 94 75 97 76 98 / 20 30 20 10 5
Denton, Texas 99 76 101 77 101 / 20 20 10 10 5
McKinney, Texas 97 76 99 76 100 / 20 30 10 10 5
Dallas, Texas 99 79 101 79 102 / 20 20 10 10 5
Terrell, Texas 97 76 99 76 99 / 20 20 10 10 5
Corsicana, Texas 97 75 99 76 100 / 10 20 10 10 5
Temple, Texas 98 76 99 75 100 / 5 10 10 10 5
Mineral Wells, Texas 100 76 101 76 102 / 10 20 10 10 5