Area Forecast Discussion
Issued by NWS Houston/Galveston, TX

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FXUS64 KHGX 252159

Area Forecast Discussion
National Weather Service Houston/Galveston TX
359 PM CST Sun Feb 25 2018

.SHORT TERM [Tonight Through Tuesday]...

Radar imagery this afternoon shows most of the shower and
thunderstorm activity north of I-10, continuing to move to the
northeast. The precipitation is situated just north of the region
with the tightest moisture gradient. The shortwave that can be
seen on GOES-16 low level water vapor imagery should continue to
shift east of the region. Expect the best chance for coverage after
sunset to slide east of I-45, as precipitation begins to clear
from northwest to southeast. Training storms similar to what we
have seen this afternoon will still be possible in the areas with
best overall precip coverage. As a result, an additional 1-2
inches of rainfall will be possible mainly north of I-10 and east
of I-45 tonight. Upper level disturbances embedded in the
southwesterly flow aloft, will continue to propagate across
southeast Texas until Monday also acting to provide dynamic
forcing for shower and thunderstorm development.

Additionally, another line of storms can be seen developing over
south central Texas this afternoon. Short term guidance is
struggling to get a handle on this line of storms. An areal flood
advisory has been issued for northern Austin and southern
Washington counties extending further east into northern
Montgomery county to account for the rainfall that has already
fallen, and any additional rainfall that may move over this
region. Any additional rainfall will only aggravate already
swollen creeks or streams and may result in additional localized
road impacts. The areal flood advisory is in effect until 630 PM
this evening.

The lingering frontal boundary acting as an axis of convergence
remains just south of I-10 this afternoon. This boundary will
have a hard time pushing much further north, as surface high
pressure attempts to build into the region. This drier airmass
will help to scoot the boundary offshore this evening and into
the overnight hours. The frontal boundary will slowly slide
south this evening. Short term guidance such as the HRRR, RAP13,
and Texas Tech WRF place the boundary in the nearshore waters
between 00-06Z Monday. Showers could linger over the coastal
waters Monday morning depending on how far the frontal boundary
moves offshore. High pressure will hold tight further inland,
allowing precipitable waters to fall between 0.4-0.9 inches.

Moisture returns to the forecast on Tuesday, as precipitable water
values climb back up to between 1.2-1.4 inches. A coastal trough
will transition north by Tuesday afternoon, and provide a focus
for shower and thunderstorm development.


.LONG TERM [Wednesday Through Sunday]...

The next cold front arrives late Wednesday evening. Precipitation
will be possible out head of this system as the front moves
through the area. Global guidance is in better agreement regarding
the timing of this frontal passage. At this time, it appears the
front should make it off the coast as upper level ridging over
the southern Gulf of Mexico weakens, and a trough deepens across
the midwest. Thursday into the weekend will be on the dry side.
Behind the front, high temperatures will range in the upper 60s to
lower 70s. Low temperatures will also fall into the mid 40s to




Visibilities have generally remained in the 3-6 mile range along the
coast today with a stalled frontal boundary located north of
Galveston. Expect this boundary to begin to shift off the coast
tonight, resulting in increasing northeasterly winds and a brief end
to the sea fog threat as it pushes into the Gulf and stalls again on
Monday. Caution or advisory flags may be needed for the coastal
waters on Monday as a result. As the front lifts back north on
Tuesday, the threat for sea fog will return and persist through
Thursday before the next cold front moves off the coast. Elevated
offshore flow will be possible behind the front, with winds
gradually becoming onshore during the upcoming weekend.




College Station (CLL)  51  70  55  71  64 /  20  10  10  60  30
Houston (IAH)          55  73  58  76  67 /  60  10  10  50  20
Galveston (GLS)        60  70  64  74  67 /  50  10  10  40  20



     afternoon for the following zones: Waters from Freeport to
     the Matagorda Ship Channel from 20 to 60 NM...Waters from
     High Island to Freeport from 20 to 60 NM.



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