Scientific Forecaster Discussion
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Area forecast discussion
National Weather Service Fort Worth Texas
506 PM CST Fri Nov 15 2019
Concerns: no significant weather impacts expected...
The center of a high pressure system over the area is allowing
light and variable winds to prevail across all of north and
central Texas this evening. As the surface high shifts east, the
winds will veer to become out of the southeast by around 03-05z.
Strong radiational cooling tonight will promote atmospheric
decoupling and keep the wind speeds less than 06 kts through the
night. By tomorrow, a deepening leeside trough will help to deepen
the pressure gradient across the region and increase the wind
speeds to around 10-15 kts in the afternoon.
VFR will prevail through the valid taf cycle with passing upper
level clouds moving into the area early in the morning hours.
Short term... /issued 310 PM CST Fri Nov 15 2019/
Mild, benign weather will prevail across north and central Texas
tonight and Saturday, as an upper level shortwave ridge builds
eastward into the Southern Plains states. Weak surface ridging
over our area this afternoon will gradually shift eastward this
evening, with Lee troughing commencing over eastern Colorado and
New Mexico. This will facilitate the development of light
southerly winds across our area later tonight through Saturday.
These southerly breezes will keep overnight temperatures up a few
degrees from the values observed area-wide this morning, though
patchy frost is still possible in some of the outlying areas of
eastern North Texas. Thanks to the southerly flow and weak
subsidence, afternoon highs on Saturday will top out a tad higher
those of today.
Long term... /issued 310 PM CST Fri Nov 15 2019/
/this weekend through next week/
A more mild night Saturday night is expected with increasing
clouds and modest southerly winds in advance of an approaching
northern stream mid level trough. This mid level trough will skirt
the area on Sunday into Sunday evening and help advance a weak
surface cold front through the area during the day. This system
will be somewhat moisture-starved and have maintained only
sprinkles along and ahead of the cold front, though this may be
mostly virga if model soundings are accurate with the dry air.
Otherwise, did lower highs a few degrees due mostly to the
increase in clouds and very light precipitation and not due to any
significant low level thermal advection. Surface high pressure
will build in Sunday night in wake of this mid-level trough and
cold front, as dry northwest flow aloft establishes across the
The dry and seasonably cool northwest flow aloft will regime will
remain present on Monday, as surface high pressure slowly exits
the area and gives way to increasing Lee-side pressure falls well
to the northwest of the area. As a mid level low cuts off off the
northwest Mexico coast and our mid level trough moves away from
the region, shortwave ridging will take hold through mid week with
dry and even slightly above normal conditions as highs reach the
70s for the first half of the work week. Meanwhile to the west,
new energy dropping south along the or/California coastline will begin
organizing our next significant storm system across the Desert
Southwest by later Wednesday. Both increasing mid level moisture
from the Pacific arriving from Mexico and an open Gulf of Mexico
will lead to increasing rain chances late in the day and
continuing Wednesday night with a lead mid level impulse. Most of
the activity Wednesday and Wednesday night should be in the form
of showers, as warmer mid levels should keep any thunder potential
isolated and elevated as low level warm advection increases with
925mb flow reach 25-35 knots.
As is usually the case with deep mid level energy in more southern
latitudes, deterministic medium range models begin to diverge and
struggle some on timing of both surface features and those aloft.
In the deterministic realm, per usual, the GFS is more
progressive lifting the deep southwest Continental U.S. Energy eastward
compared to the slower European/Canadian solutions. With no signs
of a "kicker" system upstream across the eastern Pacific or
western Canada, the geps ensemble picks up on the slower solutions
of the European and Canadian deterministic solutions as well.
This looks like a very reasonable scenario considering the semi
Rex-block ridge feature that becomes prominent across the Pacific
northwest later next week.
Look for periodic, though likely nebulous mid level impulses to
exit out of the upper low situated well to the west of our area
during the latter half of next. This will give low to moderate
convective chances off and on across the area through the period.
The best chances appear to be overnight Wednesday into Thursday
evening, when a surface cold front will add to the forcing
equation for showers and a few thunderstorms. At this time, deep
layer shear looks substantial on the other side of the storm
equation, instability, does not look overly impressive. I will
include the best chance of thunderstorms on Thursday, but more
remains to be seen on how this multi-faceted system actually
evolves and will not try to get to detailed until more clues are
revealed. Otherwise, a cooler end to next week by Friday and into
the early weekend, as highs fall back into the 50s with lows back
to between 35 and 45 degrees.
Preliminary point temps/pops...
Dallas-ft. Worth 39 60 42 61 43 / 0 0 0 10 5
Waco 35 61 40 65 41 / 0 0 0 10 10
Paris 34 57 36 58 40 / 0 0 0 10 5
Denton 34 60 41 61 41 / 0 0 0 10 5
McKinney 33 59 40 61 41 / 0 0 0 10 5
Dallas 39 61 42 63 44 / 0 0 0 10 5
Terrell 34 60 39 63 41 / 0 0 0 10 5
Corsicana 38 60 39 63 43 / 0 0 0 10 10
Temple 34 62 41 64 42 / 0 0 0 10 10
Mineral Wells 34 63 40 61 39 / 0 0 0 10 5