Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Fort Worth Texas
631 PM CDT Friday Sep 4 2015
For the 00z tafs...VFR conditions and southerly winds are
expected to persist through the forecast period.
Upper level ridging is expected to remain in place over the region
for the next couple of days. This will generally keep
precipitation chances near area taf sites low...despite persistent
southerly winds keeping low-level Gulf moisture across the area.
Without a low-level jet...think that an early morning stratus
intrusion is unlikely.
Previous discussion... /issued 343 PM CDT Friday Sep 4 2015/
an upper level high will intensify and sit right over The Heart of
Texas this weekend. The increasing subsidence aloft will result in
warming temperatures and a suppression of convective potential
despite a notable increase in deep layer moisture. However
because precipitable water will be near or exceed 2 inches across
the eastern half of the area...we cant discount the low potential
for a few isolated showers and storms during the heat of the day.
Will show 10-20 probability of precipitation over the eastern County Warning Area Saturday through Monday.
Given the combination of increasing moisture and temperatures
rising into the middle and upper 90s...heat index values will range
from 100-105 this weekend and into early next week. The good news
for many is that some relief is on the way as the upper level
pattern shifts and brings the westerlies southward...a certain
sign of the changing season.
There is now good model agreement that a cold front will push
through the region late next week with good chances of rain.
However model discrepancies remain on how quick the upper level
high over Texas breaks down and allows the upper level westerlies
into the region. The GFS maintains the upper high into
Thursday...while the European model (ecmwf) and Canadian erode it Tuesday evening.
The latter solution would result in convective activity wandering
into the region from Oklahoma starting Tuesday night and continuing
into Thursday. Although this rain would be well ahead of any cold
front...the temperatures would cool down due to increased clouds
and rain in the area. The GFS solution means dry weather will
prevail and temperatures will continue to stay hot through Thursday.
Either way...this is all several days out...so it is probably not
appropriate to pick either solution at this point. I do have a
hunch that the upper high will stay in tact through midweek. This
is because the upper trough passes well north of the region Tuesday
and Wednesday which means erosion of the ridge may be minimal.
For the official forecast Tuesday through Thursday have hedged
consensus rainfall probabilities toward the dry side and have
shown just a slight cool down in temperatures.
Confidence in rainfall does not ramp up until Thursday afternoon
and night when the main front and second upper trough axis plows
into the region. Rain chances will likely continue behind the
front into Friday and therefore temperatures may be starkly cooler
depending on the amount of Post-frontal cloud cover. It is too
many days out to get too aggressive with this possibility...but
for now will show highs Friday dropping into the 80s areawide.
Northeasterly winds and dry/cool advection will likely continue
into the following weekend with temperatures near or just below
normal as the front reaches the Gulf Coast.
Preliminary point temps/pops...
Dallas-ft. Worth, Texas 78 97 78 99 79 / 0 10 5 5 5
Waco, Texas 76 97 76 99 76 / 5 5 5 5 5
Paris, Texas 73 96 74 97 75 / 5 10 10 20 10
Denton, Texas 77 96 76 98 77 / 0 10 5 5 5
McKinney, Texas 76 96 76 98 77 / 5 10 5 10 5
Dallas, Texas 79 98 79 100 80 / 5 10 5 5 5
Terrell, Texas 76 95 75 98 78 / 5 10 10 10 5
Corsicana, Texas 75 97 76 98 77 / 5 10 10 10 5
Temple, Texas 74 97 74 97 75 / 10 5 5 5 5
Mineral Wells, Texas 73 96 73 98 74 / 0 5 5 5 0