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Area Forecast Discussion (AFD)

Issued by Houston/Galveston, TX (HGX)

                            
000
FXUS64 KHGX 221017
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
417 AM CST Fri Feb 22 2019

.DISCUSSION...
At 300 AM, low pressure was located east of the lower/middle 
TX coast with a warm front extending to the north and east of the
low. A weak trough of low pressure was noted across north central
LA extending southwest into SE TX. Showers have developed along 
this weak trough and will continue to do so through the morning. 
No lightning yet, but it would not come as a surprise if lightning
develops as the storms move off to the north. There should be a 
gap in the precipitation later this morning but a weak vort lobe 
will approach the area from the west and this should trigger 
additional showers and thunderstorms this afternoon. PW values do 
increase to between 1.40 and 1.70 inches and with a warm front 
near by, feel there should be a good chance of shra/tsra by 
afternoon. That said, most of the activity should remain benign as
fcst soundings show a dry layer between 850-500 mb and weak 
capping in the 850-700 layer. SREF ensembles and short term 
guidance still keeping sea fog near the coast today which seems 
reasonable considering 70 degree dew point air is flowing over 58 
degree shelf waters. Winds pick up later today/tonight and that 
could mitigate the fog threat but will keep a mention of fog in
the weather grids through Saturday morning.

Clouds will persist tonight and temperatures will remain nearly
steady or slowly warm overnight in the wake of todays warm front.
Fcst soundings support some drizzle overnight. The drizzle will
transition to showers as moisture profiles saturate. A cold front
will approach the NW parts of the region by 12z and showers and
thunderstorms will increase in coverage. Some of the storms could
be strong toward Saturday morning. SPC has placed the eastern 
half of SE TX in Marginal Risk and the extreme NE part in Slight 
Risk for severe weather. This again appears to be reasonable as 
capping weakens and lapse rates steepen to about 7.0 C. CAPE is 
so-so but Mu CAPE reaches about 1770 J/Kg. PW values reach 1.80 
inches and K index values reach 40 over the far eastern parts of 
the CWA. The most likely severe weather hazards expected will be 
hail (wet bulb zero around 10000 feet) and strong gusty winds. 
WPC has the area outlooked in Marginal Risk for heavy rain but the
system is fast moving so not expecting much in the way of heavy 
rain. Skies will clear by early afternoon and the bulk of Saturday
looks pretty nice once the storms exit. 

Sunday and Monday look nice with high pressure over the central
plains ridging into Texas. Moisture returns Monday night and
showers should redevelop over the area. Fcst soundings show a
saturated layer from the surface up to 700 mb. Conditions look to
remain unsettled until another cold front crosses the region
on Thursday. 43

&&

.MARINE...
A Dense Fog Advisory remains in effect through 9 AM across both 
Galveston and Matagorda Bays, as well as the nearshore waters this 
morning. Observations have been varying between 0.5 to 1 nm, and 
webcams along the coast confirm areas of fog with pockets of dense 
fog. There is the potential for this advisory to be extended, as 
favorable conditions for sea fog look to continue until the passage 
of the next cold front Saturday afternoon. 

Northwesterly winds should shift out of the southeast today as a 
warm front progresses inland late this morning and washes out over 
the area. Moisture values will rise and better coverage of showers 
can be anticipated today through tomorrow morning. Moderate onshore 
flow is forecast for Saturday morning ahead of the next cold front 
which should push through the region Saturday afternoon. Showers and 
thunderstorms are expected along and out ahead of this frontal 
passage. Moderate northwesterly winds will prevail behind the 
boundary beginning late Saturday afternoon through Sunday morning.

Winds will turn easterly late Sunday and remain out of the east 
through Tuesday morning before turning back onshore. As a result, 
tide levels are forecast to rise to around 2.5 ft above MLLW. The 
chance for showers returns to the forecast Tuesday through the 
remainder of next week. Better coverage of showers will be possible 
Wednesday into Thursday, with the approach of our next shortwave 
disturbance. Additionally, another cold front looks to move through 
the region next Thursday.

Hathaway

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)      64  58  70  43  64 /  40  60  60   0   0 
Houston (IAH)              69  65  74  48  67 /  60  40  80   0   0 
Galveston (GLS)            68  65  72  54  65 /  40  20  60   0   0 

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...Dense Fog Advisory until 9 AM CST this morning for the following 
     zones: Coastal waters from Freeport to Matagorda Ship 
     Channel TX out 20 NM...Coastal waters from High Island to 
     Freeport TX out 20 NM...Galveston Bay...Matagorda Bay.

&&

$$