May 2016: Shower/Storm Chances To End May

[unome]

NWSChat, Local Storm Reports for TX WFOs today

• https://nwschat.weather.gov/lsr/#AMA,BR ... 70459/1110

COD 1km radar loop

• http://weather.cod.edu/satrad/?type=SE_ ... verDim=100

enhanced funktop loop

• http://www.ssd.noaa.gov/goes/east/sc/h5-mloop-ft.html

[unome]

crazy rain totals

• http://radar.weather.gov/radar_lite.php ... P&loop=yes

*added HGX

• http://radar.weather.gov/radar_lite.php ... P&loop=yes

[unome]

from http://mesonet.agron.iastate.edu/wx/afo ... 1605161139

Area Forecast Discussion
National Weather Service Houston/Galveston TX
639 AM CDT MON MAY 16 2016

.AVIATION...
A bit of a difficult forecast for today. An MCV off the coast of Matagorda Bay will likely steal the moisture and energy from inland convection this morning and likely into this afternoon. However, model consensus is for some chances for showers or thunderstorms to persist into at least the early afternoon period. This will depend upon the cloud cover and whether or not any daytime heating can become established in order to destabilize the airmass. Best thunder chances will be mainly KHOU to the coast.

Forecast confidence is moderate to high for this morning, and moderate to low for this afternoon and tonight.

Chances for thunderstorms are possible again on Tuesday afternoon.


Meanwhile, Carnival Liberty back in Galveston this AM

• Galveston cams: http://www.galveston.com/webcams/

[Ounce]

Looking at another radar, it sure is easy to see the Low that's off the coast of Corpus and moving ENE.

[srainhoutx]

Monday morning briefing from Jeff:

Flash Flood Watch issued for the following counties: Fort Bend, Galveston, Brazoria, Matagorda, Jackson, Wharton, Calhoun.

Tremendous rainfall overnight of 8-12 inches has occurred in the Corpus Christi area with significant flash flooding ongoing in Rockport, Port Aransas, and Corpus Christi. This continues to show the capability of this air mass to produce some tremendous rainfall amounts.

High resolution models have done a good job at showing the formation and movement of the complex of storms this morning along the middle TX coast. Appears a meso low has formed just SW of Port O Connor and will move E across our coastal waters this morning. Moderate to at times heavy rainfall is occurring north of this feature over Calhoun, Jackson, Matagorda, and Wharton Counties and will spread into Brazoria and Galveston Counties later this morning. Radar trends support the heaviest rainfall remaining offshore.

Will need to watch for re-development of thunderstorms this afternoon behind the initial complex especially with any surface heating. Some of the high resolution models are showing this trend.

Tuesday:
Air mass Tuesday will become highly unstable as temperatures warm into the mid and upper 80’s. CAPE values soar to between 4000-4500 J/kg with very low LI’s. A weak front will approach in the late afternoon hours and expect numerous thunderstorms to develop along the boundary. Extreme amounts of instability strongly support a severe weather threat with large hail and damaging winds possible. Expect storms to go well into the evening hours and possibly overnight. Heavy rainfall will also be a concern with these storms given good organization.

Wed-Fri:
Potential heavy rainfall and flash flooding possible during this period with several disturbances and stalled front over the region. Moisture levels surge to near 2.0-2.2 inches of PW with upper level winds going strongly divergent over the region. This will help support sustained slow moving convection with very high rainfall rates. This period will certainly need to be watched for excessive rainfall and flooding.

Hydro:
Rises on area rivers and creeks is underway from the weekend rainfall and with additional rainfall expect rises to continue which may bring some rivers to near flood stage this week. Heavy rainfall this morning has resulted in a very rapid rise of the Tres Palacios River in Matagorda County.

Severe Weather Outlook (Tuesday):

day2otlk_0600 (2).gif

[srainhoutx]

Flood Watch cancelled for Wharton, Brazoria, Ft. Bend and Galveston Counties.

URGENT - IMMEDIATE BROADCAST REQUESTED
FLOOD WATCH
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
713 AM CDT MON MAY 16 2016

BRAZORIA-FORT BEND-GALVESTON-WHARTON-
INCLUDING THE CITIES OF...ALVIN...ANGLETON...EL CAMPO...
FREEPORT...FRIENDSWOOD...GALVESTON...LAKE JACKSON...LEAGUE CITY...
MISSOURI CITY...PEARLAND...PIERCE...RICHMOND...ROSENBERG...
SUGAR LAND...TEXAS CITY...WHARTON
713 AM CDT MON MAY 16 2016

...FLASH FLOOD WATCH IS CANCELLED...

THE FLASH FLOOD WATCH FOR A PORTION OF SOUTHEAST TEXAS HAS BEEN
CANCELLED. THE HEAVIER RAIN HAS SHIFTED EAST OVER THE GULF OF
MEXICO AND THE THREAT FOR FLASH FLOODING HAS DIMINISHED.

[unome]

$$

TXZ235-236-161600-
/O.EXT.KHGX.FF.A.0004.000000T0000Z-160516T1600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
JACKSON-MATAGORDA-
INCLUDING THE CITIES OF...BAY CITY...EDNA...PALACIOS
713 AM CDT MON MAY 16 2016

...FLASH FLOOD WATCH NOW IN EFFECT UNTIL 11 AM CDT THIS MORNING...

THE FLASH FLOOD WATCH IS NOW IN EFFECT FOR

* PORTIONS OF SOUTHEAST TEXAS AND SOUTHEAST TEXAS...INCLUDING
THE FOLLOWING JACKSON. ...MATAGORDA....

* UNTIL 11 AM CDT THIS MORNING

* VERY HEAVY RAIN IS EXPECTED THIS MORNING WITH ADDITIONAL
RAINFALL OF AROUND AN INCH IS POSSIBLE. GROUNDS REMAIN
SATURATED FROM PREVIOUS RAINS OVER THE WEEKEND AND ANY
ADDITIONAL RAIN WILL RUN OFF QUICKLY AND COULD PRODUCE FLASH
FLOODING.

* DO NOT DRIVE YOUR VEHICLE INTO AREAS WHERE THE WATER COVERS
THE ROADWAY. THE WATER DEPTH MAY BE TOO GREAT TO ALLOW YOUR
CAR TO CROSS SAFELY. VEHICLES CAUGHT IN RISING WATER SHOULD BE
ABANDONED QUICKLY. IF YOUR VEHICLE STALLS...ABANDON IT AND
SEEK HIGHER GROUND IMMEDIATELY. RAPIDLY RISING WATER MAY
ENGULF YOUR VEHICLE AND ITS OCCUPANTS AND SWEEP THEM AWAY.
MOVE TO HIGHER GROUND.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A FLASH FLOOD WATCH MEANS THAT CONDITIONS MAY DEVELOP THAT LEAD
TO FLASH FLOODING. FLASH FLOODING IS A VERY DANGEROUS SITUATION.

YOU SHOULD MONITOR LATER FORECASTS AND BE PREPARED TO TAKE ACTION
SHOULD FLASH FLOOD WARNINGS BE ISSUED.

&&

$$

[unome]

4310: Brazos River @ SH 36 (Freeport)

• http://www.harriscountyfws.org/GageDetail/Index/4310

[DoctorMu]

The forecast is interesting and complex. Impulses have stayed south along the trough and front as it hugs the coast. Temperatures have underperformed (or better the cool air has overperformed) north of I-10 for a couple of days as the front remained south of predicted. As of 8:55, the HGX office finally lowered the afternoon highs to reflect this...and we're struggling to lift out of the 60s in CLL.

A warm front has been expected to lift northwards, but am suspicious of an upper 80s forecast tomorrow pm north of Navasota. We'll see.

[brooksgarner]

I'm optimistic that we'll escape the worst of it... The WILD CARD will be tomorrow's severe threat... and Thursday. Obviously, if we see training storms under 4,000 CAPE values with -11 LI's and higher PWATS, many areas will flood... Seeing as how Corpus got 10"+ this morning! But, I'm not seeing the red flags that we did of the Tax Day floods last month.

My video forecast update --> https://www.youtube.com/embed/CezH5odnFuM

[ticka1]

just dont let your guard down or become complacent

[brooksgarner]

just dont let your guard down or become complacent

Exactly!

[Andrew]

GFS continues to be rather slow in moving the rain out. Rain chances stay in the forecast until early/middle of next week. Biggest concern will be tomorrow with possible severe weather and Thursday evening when a line could move through. Luckily the progression of everything should allow for periods of drying and keep widespread flooding down to a marginal risk. Active week ahead.

[srainhoutx]

Looking forward to the Memorial Day Holiday Weekend and the end of May, the afternoon updated Climate Prediction Center is suggesting more of the same regarding our sensible weather pattern.

[ticka1]

so the early forecast for memorial day is rain to continue?

[brooksgarner]

Obviously impossible to point to a model and declare it accurate three days from today, but the EURO is erratically pumping out 6 hour rainfall totals (as displayed here in 24hour totals) of over 5" in the Harris County flood zones on Thursday. If we got a thunderstorm complex dumping rain of that caliber, we'd flood pretty fast.

ecmwf_precip_24_houston_17.png

[Ptarmigan]

Looking forward to the Memorial Day Holiday Weekend and the end of May, the afternoon updated Climate Prediction Center is suggesting more of the same regarding our sensible weather pattern.

Some of the analog dates stand out, like 2002, 2004, and 2006. They were wet.

[djjordan]

Good Tuesday morning to everyone. Weather remains unsettled through the week. Here's the morning Forecast Discussion from the NWS

Area Forecast Discussion
National Weather Service Houston/Galveston TX
420 AM CDT TUE MAY 17 2016

.DISCUSSION...
An active flow aloft will keep chances for rain and thunderstorms
in the forecast through the end of the week. A building upper
level ridge over Texas should then quiet down the unsettled
weather pattern a bit over the weekend and into early next week.

The main item of concern for the next few days will be rainfall
coverage and amounts. This morning should see a break in the
rainfall coverage. An approaching upper level shortwave trough
will then bring at least isolated coverage this afternoon into
this evening. Chances for isolated strong or severe storms today
may depend upon when the low-level capping inversion will erode.
The latest Nambufr soundings show the potential for development
to begin during the late afternoon and continue through most of
the evening. MUCAPE values are forecast to reach between 3000 and
4000 as the Nam12 moves a pattern of vorticity advection overhead
during this time period. The Texas Tech 4km WRF has the
thunderstorm development in the south central portion of the state
with the storms then moving eastward into SE Texas during the
evening. On Wednesday rain and thunderstorm chances will
increase as a frontal boundary moves toward and into SE Texas from
the north.

Better rainfall coverage is forecast by the models on Thursday.
NAEFS model mean PW/s are forecast to reach to between 1 and 2
standard deviations above normal. Given the surface boundary that
will be in place plus the splitting upper level jet that is
forecast to be overhead, think that locally heavy rainfall may be
possible. A lot will depend upon how things set up and would like
to see another day`s worth of model runs in order to pinpoint any
areas where the heavier rainfall will set up. For now, a model
consensus would point toward the areas between Crockett,
Madisonville, and College Station. However, some models are
keeping the heavier rainfall well west of the forecast area. Best
advice for now is to stay tuned for later forecast updates.

Although an upper level shortwave ridge is expected to develop
overhead this weekend and early next week, isolated to scattered
rainfall coverage is still expected. However, these will be
accompanied by warming temperatures. By the weekend and on
Monday, daytime high temperatures are expected to reach to near or
above normal for this time of year -- the mid and upper 80s.

40

&&

.MARINE...
Light winds this morning should become stronger from the southeast
this afternoon and tonight. This should allow for seas to continue
to subside. Winds turn easterly tomorrow as a frontal boundary
stalls just onshore the Upper Texas Coast. East to southeast winds
increase Thursday which may allow for seas around 4 to 6 feet. Winds
decrease headed into the weekend which will allow for seas to
decrease again. Thunderstorm activity may become more wide spread
Thursday into Friday as an upper level trough moves across Texas.

Tide levels remain elevated this morning but should be decreasing
with light winds in place. Tides may become higher Thursday as east
to southeast winds increase. Tides along Gulf facing beaches may
reach slightly above 3 feet MLLW which could have some minor impacts
to Bolivar.

Overpeck

[srainhoutx]

Tuesday morning briefing from Jeff:

Highly active weather pattern continues.

Cool front and next upper level disturbance will approach SE TX this afternoon. Air mass is becoming increasingly capped this morning and with low clouds and fog it will take a period of heating to help erode this capping today. By mid to late afternoon the capping should begin to erode and strong heating over WC TX should allow severe thunderstorms to develop.

These thunderstorms will gradually congeal into a line or complex of storms and move ESE to SE toward SE TX this evening. Large hail and damaging winds will be the main threats with these storms.

Think our western counties will have the highest risk of severe weather with the storms potentially weakening as they move eastward over the region late tonight.

Front stalls across the area on Wednesday with additional showers and thunderstorms expected ahead of what looks to be a very active Thursday as a strong disturbance moves across the region resulting in widespread thunderstorms with heavy rainfall. PWS rise to near 2.0 inches on Thursday which really ramps up the heavy rainfall threat. Still too early to define any one risk area over another for Thursday for any potential flooding…but this period will have to be watched closely.

Severe Weather Outlook (Today):

day1otlk_1300.gif

[DoctorMu]

Temps continue to underperform as the warm front never materialized...yet. Winds now out of the NE so cool and moist continues until storms arrive Thursday am. I'd take cool and cloudy all summer long. That's a fantasy dream CLL summer, where plants survive and A/C and water bills remain low! haha.