April 2017 - MS 150 Forecast This Weekend

[DoctorMu]

Looks like another seabreeze today over the area, interacting with unstable air, and reaching College Station in the evening.



Area Forecast Discussion
National Weather Service Houston/Galveston TX
446 AM CDT Wed Apr 19 2017

.DISCUSSION...
Keeping a close eye on the large area of showers that developed
offshore overnight and is presently moving toward the Matagorda
Bay/Matagorda coast. Cloud tops have warmed during the last few
hours...but we should see some of this activity make it onshore
shortly. While this particular area of SHRAs is not expected to
persist as it moves further inland, it does underscore the idea
that the airmass over the region is remaining somewhat unstable
(due in large part to the proximity of the main upper low/weak-
ness aloft).Daytime heating/lingering boundaries and progged PW
values AOA 1.7 inches are all supportive of scattered SHRA/TSRA
across SE TX this afternoon.

The building upper ridge from the W/SW tomorrow will help lower
POPS for Thurs...with the seabreeze as the main focus for isol-
ated/widely scattered afternoon storms. As the next upper trof/
low moves into the Central Plains we should see an increasingly
warm/dry mid-level flow develop across the area by Fri. If this
does verify, we could see much more limited activity along/just
ahead of the associated cold front which is slated to move thru
SE TX on Sat. 41

[Katdaddy]

A slight chance of afternoon showers and isolated thunderstorms today and Friday. A 20-30% chance of showers and isolated thunderstorms Saturday ahead of cold front that will drop temps into the 60s and low 70s Saturday afternoon and lows into the upper 40s to low 50s by Sunday morning.

[Katdaddy]

NTX thunderstorms have dissipated as they moved into SE TX early this morning. A few showers and an isolated thunderstorm will be possible along the cool front today. A very nice Saturday evening on the way followed by beautiful perfect Sunday weather.

[MontgomeryCoWx]

Thank God the humidity and nasty hot weather is gone for a few days.

[mckinne63]

What a gorgeous weather day in SE Texas. I can't remember the last time I was able to open the windows and feel the lovely breeze blowing through the house.

[djmike]

Any upcoming severe events in the near future? Just curious. Thanks

[jasons2k]

What an absolutely gorgeous weekend! That was probably it until October...

[tireman4]

Any upcoming severe events in the near future? Just curious. Thanks

Well since you mentioned it..there is this. Now, Srain, Andrew, Wxman 57 and other pro mets can further extrapolate this but...

https://twitter.com/MJVentrice

[Katdaddy]

A partly sunny warm day ahead for SE TX. There will not be much of cool down behind tomorrow's cool front. A few showers and a thunderstorm may be possible along the front but more significant storms will be well NE of Houston metro from ETX across the ARKLATEX and into the lower to mid MS Valley.

[srainhoutx]

BP MS 150 Bike Ride is this Saturday and Sunday as we end April. Looks like a front will push across the Hill Country Saturday evening and advance to the Coast during the day on Sunday. The current 48 Hour Quantitative Precipitation Forecast suggests a chance of some heavy training rainfall Saturday afternoon as the riders near La Grange. Sunday looks a bit drier behind the front, if it pushes all the way to the Coast. We will see.

[wxman57]

Once again, for the third year in a row, the MS 150 bike ride from Houston to Austin may be plagued by a line of heavy to severe thunderstorms. Latest GFS indicates that the line of showers/storms will impact the La Grange overnight rest stop Saturday night. The rain could be over with by the time the ride resumes on Sunday morning, but watch for Sunday's temperatures to be 10-15 degrees cooler than Saturday.

[Katdaddy]

A significant severe weather event is likely across the ARKLATEX with Moderate Risk area. An Enhanced Risk area stretches from NE TX to S MO.

The temperature roller coaster continues. A few light showers will be possible across SE TX today with very warm temps that may reach 90F. This evenings front will drop overnight lows down to the upper 40s well inland to 50s across Houston metro. A few thunderstorms will be possible if the cap weakens late this afternoon as the front moves across the area. Areas NE of Houston metro have the best chance of some strong to severe storms if the cap weakens with a Marginal Risk area.

A quick rebound from a cool Thursday morning into the upper 70s and 80 with return flow beginning. The onshore flow increases Friday with temps possible reaching 90F.

[srainhoutx]

Wednesday morning briefing from Jeff:

A strong storm system will approach SE TX this weekend.

Cold front currently moving into N TX will progress southward today and across SE TX this afternoon. Ahead of the boundary SW flow at the surface will push temperatures well into the 80’s and possibly near 90 before the front arrives. Area is strongly capped this morning and even with the tail end of a short wave and lift along the front, do not think the cap will be overcome for most of the area. Capping will be weakest from roughly College Station to Chambers County and areas NE of that line may see an isolated strong thunderstorms with the front this afternoon.

Much cooler and drier on Thursday, but this will be short lived as the next system rapidly approaches from the west. Low level southerly flow begins in earnest late Thursday and increases on Friday helping to transport and tropical air mass northward into east TX. Approaching strong short wave will deepen into a closed upper level low over the SW US early Saturday and barrel into TX late Saturday into Sunday. Expect strong moisture advection on Saturday to promote scattered showers and even a few thunderstorms be the afternoon hours.

Main event will arrive into the region Saturday night into midday Sunday with strong forcing aloft helping to erode capping allowing deep convection to develop. Instability and shear values look favorable for strong to severe thunderstorms and PWS rise to near 2.0 inches by Saturday evening which will support a heavy rainfall threat. SPC has areas just to our north outlooked for severe weather this weekend and will need to watch trends to see if this needs to be expanded southward which appears possible depending on mid level capping.

As for rainfall widespread 1-2 inches will be possible this weekend with the greatest chances along and NE of a line from Bastrop to Sugar Land to Galveston. Could certainly see some isolated higher totals with PWS so high, but the system currently looks progress enough to keep things manageable over the region.

[tireman4]

695
FXUS64 KHGX 261736
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
1236 PM CDT Wed Apr 26 2017

.AVIATION...
Light SHRAs with the pre-frontal trof have moved off the coast at
present...and keeping an eye to our N/NE with the development at/
along the cold front itself. Still banking on the strong cap over
the region to keep any additional precipitation out with FROPA it-
self and main change with the 18Z TAFS was to tweak the timing of
the front. Otherwise, quite a bit of haze lingering across the FA
in the wake of the pre-frontal trof with some spots of MVFR CIGS.
All of this should clear out behind the front with VFR conditions
areawide this evening/overnight/most of tomorrow. 41

&&

.PREV DISCUSSION... /ISSUED 1027 AM CDT Wed Apr 26 2017/

UPDATE...
The previous forecast appears to be on track. We currently have a
few warm air advection showers pushing through parts of SE Texas
this morning. 12Z soundings from CRP and LCH showed a very strong
cap in place. I have some doubts as to how much of the cap will
really be able to erode by this afternoon when the approaching
front pushes into our area. The best chance for breaking the cap
and therefore getting thunderstorms will be generally to the
northeast, or across the Piney Woods region. If we are able to
break through the cap, steep mid level lapse rates of around
7.5-8.0 and forecast CAPE over 3000 will give any thunderstorms
that do develop the potential to pack some damaging winds and
large hail. The tornado threat is also nonzero and something to
monitor, but for now the greatest threats appear to be damaging
winds and hail. 11

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL) 86 51 84 67 90 / 20 0 0 10 10
Houston (IAH) 89 56 84 69 90 / 20 10 0 10 10
Galveston (GLS) 84 64 78 74 82 / 20 10 0 10 10

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT SHOULD EXERCISE CAUTION until 4 PM CDT this
afternoon for the following zones: Coastal waters from
Freeport to the Matagorda Ship Channel out 20 NM...Coastal
waters from High Island to Freeport out 20 NM...Galveston
Bay...Matagorda Bay.

Small Craft Advisory until 4 PM CDT this 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.

&&

$$

[Katdaddy]

Temps mostly in the 50s across SE TX with some upper 40s well inland and a few 60s along the coast. A beautiful day with warming temps into the low 80s this afternoon. Increasing GOM moisture and very warm temps up to 90F on Friday. Severe thunderstorms and locally heavy rain will be possible across SE TX late Saturday night and early Sunday morning. The SPC has most of SE TX in a Slight Risk area.

[Katdaddy]

High temps in the upper 80s and low 90s across SE TX this afternoon with increasing moisture and gusty S winds. A Coastal Flood Watch has been issued for the Upper TX Coast Saturday due to near gale force onshore winds, long swells, and high surf. Water levels could reach 3.8ft or higher resulting low lying coastal flooding. Saturday the MS-150 will experience cross winds gusting to 30MPH on the way to La Grange with showers and isolated thunderstorm possible.

A potentially stormy Saturday night and early Sunday morning for SE TX. The SPC has a large Enhanced and Slight Risk areas across, N, S Central, SE, and E TX. Locally heavy rain will also be a possible.

[tireman4]

It will be warm out there folks. Stay hydrated.


000
FXUS64 KHGX 281121
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
621 AM CDT Fri Apr 28 2017

.AVIATION...
Main issues this morning will be timing of the MVFR conditions
lifting to VFR and an increase in the wind speeds. Should see
winds increasing before or as the ceilings lift. Patchy fog or
haze possible at the coast. During the late morning and afternoon
winds will become gusty. Tonight the winds will stay up even as
the ceilings once again lower to MVFR. At the coast and near
Galveston Bay winds may gust to 25 to 30 knots. Overnight tonight
wind gusts to near 34 knots are possible at KGLS.

40

&&

.PREV DISCUSSION... /ISSUED 408 AM CDT Fri Apr 28 2017/

DISCUSSION...
At 100 AM, an area of low pressure was located over west Texas
with a dry line extending from about Lubbock to Ft Stockton. The
pressure gradient across east Texas was tightening in response to
the deepening area of low pressure out west. South winds will
strengthen throughout the day and breezy conditions will prevail
by afternoon. High temperatures today are conditional on when the
clouds break and the amount of mixing produced by sfc winds. 850
temps are progged to reach 25 C this afternoon and bringing these
values down to the sfc dry adiabatically will produce sfc temps
between 98-100. Clouds for the first half of the day should moderate
temps a bit but once sunshine returns in the aftn, feel temps could
rise pretty quick. Heat index values will climb today and will
probably top out in the upper 90s this afternoon. It will feel
more like summer today. Min temps tonight should remain very warm
with clouds filling back in during the evening to help insulate.
Winds will remain strong so mixing will also keep temps from
falling much. Would not be surprised if a few locations remained
near or above 80 degrees overnight.

The strong winds will also produce elevated tides late tonight. Water
levels could reach values between 3.5 and 4.0 feet and this would produce
some flooding along the coast, especially along the Bolivar peninsula. A
coastal flood watch has been issued for late tonight through
Saturday with the best window for coastal flooding around sunrise
Saturday.

Saturday will remain warm with high temps warming into the
mid/upper 80s. Could get a few showers beneath a strong capping
inversion Saturday morning as the low level jet nears the
area. There could be some aftn convection as strong capping in
the morning gradually weakens, PW values climb to 1.90 inches and
convective temps drop into the mid 80`s.

Strong thunderstorms are expected to move across SE TX Saturday
night. SPC has outlooked much of the region in Slight or Enhanced
Risk for Saturday night. CAPE values will 3000 J/Kg, LI values
between -9 and -11, lapse rates around 7.0 C and helicity values
between 180 and 300 m2/s2. Jet structure shows a nice split in the
winds at 300 mb so it appears all the parameters are in place for
a severe weather event Saturday night. So what could go wrong?
Fcst soundings show a very strong capping inversion that just
vanishes as a cold front and upper level dynamics approach. Not
sure the cap will erode as the models suggest, especially over the
southern half of the region. Took a look back at the CIPS analog
page and previous events with this type of weather pattern only
showed a few severe weather reports over the extreme northern
parts of SE TX. There is still a great bit of uncertainty how this
weather event will unfold so keep up with the forecasts. The cold
front will still trigger a line of shra/tsra Saturday night and
the CIPS page showed about 0.50 to 1.00 inch of rain with past
events. Most of the area should receive some rain with the
heavier totals to the north.

Rain should end around sunrise Sunday morning with skies clearing
by afternoon. High temps will trend cooler with max values in the
mid/upper 70s. Dry conditions will prevail Monday but moisture
levels begin to increase on Tuesday and a few showers will be
possible by Tuesday night as an upper level trough approaches
from the west. The trough coupled with a sfc cold front will bring
the area a good chance of showers and thunderstorms on Wednesday.
Fcst soundings again show some potential for strong storms with
CAPE values above 3500, steep lapse rates and LI values around
-10. Clearing conditions and cooler temperatures are expected in
the wake of the front for Thursday and Friday.

MARINE...
Winds over the bays and Gulf waters are expected to pick up and will
probably reach caution criteria toward sunrise. The big event will
then set up later with advisory conditions expected by sunset. Gusts
to gale force are likely over the Gulf waters later tonight through
at least early Sunday. Winds should diminish as a cold front
approaches the coastline. The result of the strong winds will be
long-period swells and high surf. Forecast models indicate the
possibility of water levels reach over 3.8 feet at Pleasure Pier on
Galveston Island and over 3.5 feet at Freeport. Because of the
potential, have issued a coastal flood watch for overnight tonight
through mid afternoon Saturday.

40

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL) 90 77 87 57 74 / 10 20 40 80 10
Houston (IAH) 90 78 87 64 76 / 10 20 30 80 30
Galveston (GLS) 84 79 83 68 77 / 10 20 20 80 60

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...Coastal Flood Watch from late tonight through Saturday afternoon
for the following zones: Brazoria...Chambers...Galveston...
Matagorda.

GM...SMALL CRAFT SHOULD EXERCISE CAUTION through this evening for the
following zones: Coastal waters from Freeport to the
Matagorda Ship Channel out 20 NM...Coastal waters from High
Island to Freeport out 20 NM...Galveston Bay...Matagorda
Bay...Waters from Freeport to the Matagorda Ship Channel
from 20 to 60 NM...Waters from High Island to Freeport from
20 to 60 NM.

Small Craft Advisory from 7 PM this evening to 2 PM CDT Sunday
for the following zones: Coastal waters from Freeport to
the Matagorda Ship Channel out 20 NM...Coastal waters from
High Island to Freeport out 20 NM...Waters from Freeport to
the Matagorda Ship Channel from 20 to 60 NM...Waters from
High Island to Freeport from 20 to 60 NM.

&&

$$

Discussion...43
Aviation/Marine...40

[srainhoutx]

Friday morning briefing from Jeff:

Large scale storm system currently over the SW US will arrive into TX this weekend.

Strong low level southerly flow overnight has returned a tropical air mass to the region with origins of this air mass from the smoke and haze filled Bay of Campeche from agricultural fires in Mexico. Low level cloud deck is already starting to break and scatter this morning and when combined with mid level temperatures well into the mid 20C range expect a very warm afternoon with surface temperatures possibly reaching the lower 90’s. This combined with dewpoints in the lower 70’s will support heat index values of 97-102 this afternoon.

Air mass will be strongly capped today into much of Saturday as the storm system approaches from the west. While SPC has outlooked nearly the entire area for severe weather on Saturday night the big question is can the capping inversion be overcome. Forecast soundings show a cap still in place Saturday afternoon although eroding due to surface heating and possibly breakable with surface temperatures in the mid 80’s which appears possible. Models then vanish the capping inversion Saturday night which seems a bit suspect given that capping usually increases after dark and while large scale lift will be increasing the lift looks slightly out of phase with the surface cold front. All of this raises questions as to the potential for severe weather, but the greatest risk areas and forecast confidence.

We have certainly seen this many times before where the cap does not erode especially south of I-10 and those area end up generally with less activity. Global forecast model QPF output is showing that signal with the main convective line passing across the northern portions of the area. While instability and shear will be more than favorable for severe weather it is questionable especially south of I-10 is storms will be able to form. Best chances for strong to severe thunderstorms will be found along and N of I-10 overnight Saturday into Sunday morning.

Moisture values really increase on Saturday with PWS surging to near 2.0 inches which is fairly high for late April. Overall progressive speed of the system and potential for capping issues precludes a significant heavy rainfall and flash flood threat. Think this threat…and a fairly significant one…will be focused from NE TX into AR. Rainfall amounts will likely average 1-2 inches north of I-10 and less than an inch south of I-10.

Marine/Coastal:
Very strong southerly inflow of 25-30kts over the next 24-36 hours will result in NW Gulf of Mexico seas building into the 9-12 foot range. These large swells will result in wave run-up along the Gulf facing beaches and elevated tides. Current tide forecast bring total water levels to near 3.5-4.0 ft on Saturday which is near warning thresholds on Bolivar and portions of the west end of Galveston. Could see some overwash and will likely have water up to the base of the dunes at most locations.

Next Storm System:
Another storm system will approach the area by the middle of next week with additional chances for showers and thunderstorms.

[srainhoutx]

Temperatures are rather toasty across SE Texas at this hour. I currently have a 94F reading on my weather station. The GFS continues to indicate a strong cap tomorrow into the overnight hours prior to the front arriving early Sunday morning. Perhaps we can squeeze out about a quarter to a half inch of rainfall tomorrow into tomorrow night, but I suspect the strongest storms will remain well NE of Metro Houston.

[javakah]

Ooph. Hope nobody's planning a camping trip in the Ozarks this weekend. The map looks rather ugly, and that's a pretty good sized area that's going to get slammed.

Although I hate to have to admit it, at the same time it's kind of nice (seemingly for once) to see an ugly QPF map and not be worrying about the proximity of the bullseye to us.