FXUS64 KFWD 202349

Area Forecast Discussion
National Weather Service Fort Worth TX
649 PM CDT Mon Aug 20 2018

/00Z TAFs/

VFR conditions will prevail with scattered to broken cirrus at
times, especially across Waco which will be just north of where
dissipating TSRA between KTPL and KAUS will provide some anvil
debris later this evening. At this time, any SHRA/TSRA should
remain south of all airports near a stationary surface front
across Central TX.

N-NW winds will be 8-11 knots will occur through sunset, before
becoming light and variable or light north AOB 5 knots overnight
with surface high pressure settling across the region.

The surface front should remain stalled south of Waco Regional on
Tuesday. Have kept VCTS/VCSH out of the forecast for Waco with
low confidence on where the surface front stalls and any
isolated TSRA expected on the front. Winds will increase to
between 5-8 knots from the N-NE by Tuesday afternoon, as the
surface ridge shifts across E TX/W LA.



.DISCUSSION... /Issued 238 PM CDT Mon Aug 20 2018/
The cold front has reached the southern zones and is beginning to
lose its forward momentum as the unusually strong cyclone over
the Midwest heads eastward. A hot and unstable airmass is
developing ahead of the front, and the lift along the boundary
should be sufficient for scattered showers and thunderstorms to
develop along and ahead of it this afternoon. The atmosphere will
be favorable for the strongest storms to produce damaging
microbursts through 7 pm. Most of this activity should diminish
with the loss of heating. However the boundary is expected to
remain in the vicinity of the far southern zones, and some of the
high res models indicate elevated showers or storms may develop
after midnight as low level flow returns to the south and weak
isentropic ascent occurs near the boundary. For PoPs will show
20-40 percent across the southern zones this afternoon,
diminishing to 20 percent after the loss of heating. The frontal
boundary will continue to be a focus into Tuesday, and will keep
20 PoPs going south of a Comanche to Waco to Centerville line.
After tomorrow, the front becomes so diffuse that the chance of
rain drops below 10 percent.

Central Texas will not get to enjoy the benefits of the slightly
cooler and drier air behind the front, but North Texas will.
Humidity is noticeably lower already, and good radiational cooling
means lows in the upper 60s are likely tonight in some outlying
areas with low 70s in urban ones. High temperatures Tuesday will
be near or just below normal over the northern half of the
region, but humidity will be much below normal. However, the
northern parts of the area look like they will contend with a
plume of smoke originating from the fires on the western side of
the continent. The worst of the smoke should stay north of the
CWA, so we are not expecting any visibilties below 5 miles, but
we have inserted a mention of haze in the forecast across the
northern and northeastern zones. Smoke/haze may hang around into
Wednesday and impact more of the region, but we`ll see how it all
transpires tomorrow before advertising it Wednesday. Otherwise
highs will generally be in the low 90s north to upper 90s south
Tuesday and Wednesday.

An upper level subtropical high will build in across the region
from the west by midweek and persist over the region into early
next week. While this will ensure rain-free conditions and hot
conditions, temperatures actually will be held in check by
persistent southerly flow in the lower levels bringing in "cooler"
air off of the Gulf of Mexico. Highs will top out in the upper 90s
to near 100 for most locations by late week and into the weekend
and with the increase in Gulf moisture this will put heat indices
in the 100-105 range.



Dallas-Ft. Worth    73  95  74  95  76 /   0   0   0   0   5
Waco                73 100  74 100  75 /  20  10   5   0   0
Paris               68  91  67  91  70 /   0   0   0   5   5
Denton              68  95  70  94  73 /   0   0   0   5   5
McKinney            68  94  70  93  73 /   0   0   0   5   5
Dallas              74  96  75  95  78 /   0   0   0   0   5
Terrell             70  95  70  95  74 /   5   0   0   0   0
Corsicana           74  97  71  96  74 /  10   5   0   0   0
Temple              74  99  73 100  73 /  20  20  10   0   5
Mineral Wells       68  97  71  96  73 /   0   0   0   5   5





NWS FWD Office Area Forecast Discussion