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Area forecast discussion
National Weather Service Fort Worth Texas
554 PM CST Fri Dec 13 2019

/00z tafs/

Concerns and challenges: minor. Potential for bcfg and MVFR/br
vsby conditions at all airports between 09z-15z Saturday.
Transition from light east/NE winds less than 10 knots...veering southeast
after 18z Saturday.

A broad and diffuse surface pressure field will occur tonight and
Saturday morning, before a weak high pressure ridge axis shifts
east of the d10 airports Saturday afternoon. Northwest flow on the
backside of the longwave mid level trough over the MS valley will
bring periods of scattered-broken mid-high clouds streaking southeast
across the area. The near surface environment will likely moisten
enough up through 1000-975mb that some bcfg conditions will occur
along and east of I-35. I have inserted a tempo group on either side
of 12z Saturday for MVFR/br conditions. The NAM is much more
aggressive with fog formation and favorable Hydro lapse rates
versus the rap/lamp solutions. I will monitor this very closely
this evening.

In addition, backing flow up through 925mb per vwps may cause
some minor low level wind shear issues up to 20 knots, but not severe enough to
mention in tafs attm. With very strong northwest flow in the 700-300mb
layer, moderate-severe turbulence will likely be an issue through
Saturday morning for commercial aircraft at dfw/Dal, along with
cargo aircraft at afw. Otherwise, near calm or light north/NE winds
less than 5 knots will become southeast at 7-10 knots Saturday afternoon.



Discussion... /issued 237 PM CST Fri Dec 13 2019/
synopsis: after a quiet weekend, a strong cold front will pass on
Monday, bringing rain and thunderstorm chances for areas east of
I-35. Much colder temperatures can be expected for early next
week, with freezing temperatures likely on both Monday night and
Tuesday night. A steady warming trend will commence by the middle
of the week, with the next rain chances coming towards the end of
the week.

Surface analysis from this morning showed that the Southern Plains
are in fairly weak flow. Light northerly winds were in place
courtesy a weak trough of low pressure stretched along the Red
River. After a foggy and cool start, we have managed to warm into
the upper 50s or lower 60s, making for a pleasant afternoon. To
the north, a frontal zone is stretched across the upper Midwest
and northern rockies, forming a separation between Continental
polar air to the south, and Continental Arctic air to the north.
The air mass to the north of this frontal zone is quite frigid,
with a balmy temperature reading of -38 f noted in southend,
Saskatchewan this morning, up near the 56th parallel. In the
upper levels, a broad trough stretches nearly coast to coast, with
the axis along a line from Winnipeg, mb to Topeka, Kansas to
Brownsville, Texas.

The upper-level pattern will remain quite progressive through the
next seven days. Weak upper-level ridging will return over the
weekend, leading to warmer temperatures. Sunday should be
spectacular with highs in the 70s expected for much of our County Warning Area.
There could be some very slight chances for showers in our far
northern counties in the morning as warm air advection resumes,
but expect the higher chances (still low) to stay up in Oklahoma.

The next upper-level trough will swing into the Great Plains on
Monday, driving a cold front south and across our region. Monday
looks to be quite chilly, with highs likely struggling to get much
into the 50s in North Texas. Gusty northerly winds will mean wind
chills staying in the 40s. Some showers and thunderstorms may
develop ahead of the cold front, mainly east of Interstate 35. In
general, rain chances will increase the farther south and east one
GOES. At this time, the severe weather threat looks to be low to
none. Rainfall totals will also be light for most locations.
Monday night will be cold with lows likely to fall to near or
below freezing for much of the County Warning Area. Tuesday night will be even
colder as winds settle down, and skies clear out, allowing for
excellent radiational cooling. The entire County Warning Area should see below
freezing temperatures on Tuesday night, with our western counties
likely falling into the lower 20s.

By the middle of next week, we should begin a slow warming trend
as southerly flow becomes established across the region. The next
rain chances will come on Thursday night and into Friday as yet
another upper-level trough approaches the region.



Preliminary point temps/pops...
Dallas-ft. Worth 42 59 47 72 42 / 0 0 0 0 10
Waco 41 64 48 76 48 / 0 0 0 0 5
Paris 39 53 42 66 44 / 0 0 0 5 30
Denton 39 58 44 71 39 / 0 0 0 0 10
McKinney 39 58 44 70 42 / 0 0 0 0 10
Dallas 42 59 47 72 44 / 0 0 0 0 10
Terrell 41 58 46 73 46 / 0 0 0 0 20
Corsicana 43 61 48 74 49 / 0 0 0 0 20
Temple 43 67 50 77 50 / 0 0 0 0 5
Mineral Wells 39 61 44 72 37 / 0 0 0 0 5


Forward watches/warnings/advisories...

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