October 2017 - Halloween Forecast/Rain Chances

General Weather Discussions and Analysis
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Katdaddy
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A disturbance is producing localized flooding rain across NW Galveston, NE Brazoria, and S Harris County. 6.42” of rain at the weather station near the house. I had to move the car out of the street so it would not take on water. Flash Flood Warning in effect.

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Houston/Galveston TX
452 AM CDT FRI OCT 20 2017

The National Weather Service in League City has issued a

* Flash Flood Warning for...
Northwestern Galveston County in southeastern Texas...
Northeastern Brazoria County in southeastern Texas...
Southern Harris County in southeastern Texas...

* Until 645 AM CDT.

* At 450 AM CDT, Doppler radar indicated heavy rain across the warned
area. Up to three inches of rain have already fallen. Flash
flooding is expected to begin shortly. The rain gage at Bay Area
Boulevard and Clear Creek has reported 4.00 inches of rain since
330 AM.

* Some locations that will experience flooding include...
League City, Texas City, Friendswood, Dickinson, La Marque, Santa
Fe, Webster, Hitchcock, southern Clear Lake and Nassau Bay.
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srainhoutx
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A strong jet speed max convergence point is situated from near Galveston Bay on East toward Beaumont and should shift out of our area this morning. Water Vapor imagery suggests a secondary but weaker speed max is approaching from the West. May not see too much more of additional flooding issues today, but isolated heavier rainfall may be possible this afternoon as the next disturbance nears our Region.

Image

Sunday looks like the next active weather day as that strong upper trough and attending strong cold front arrives early to mid day Sunday with a line of possibly strong to severe thunderstorms.

Much cooler and drier weather is ahead through at least mid next week as a secondary shot of Canadian air sneaks into East Texas on Tuesday.
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srainhoutx
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Special Weather Statement
National Weather Service Houston/Galveston TX
636 AM CDT FRI OCT 20 2017

Chambers TX-Galveston TX-
636 AM CDT FRI OCT 20 2017

...SIGNIFICANT WEATHER ADVISORY FOR CENTRAL GALVESTON AND SOUTH
CENTRAL CHAMBERS COUNTIES UNTIL 715 AM CDT...

At 635 AM CDT, Doppler radar was tracking a strong thunderstorm near
Port Bolivar, or near Galveston Pier 21, moving north at 25 mph.

Winds in excess of 40 mph will be possible with this storm. The
storm is showing signs of rotation at times and a tornado could form
with little or no warning.

Locations impacted include...
Smith Point, Crystal Beach and Bolivar Peninsula.
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srainhoutx
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Friday morning briefing from Jeff:

Heavy rainfall possible through the weekend.

Very active morning over portions of the area with intense short term rainfall rates. Clear Creek at Bay Area Blvd recorded nearly 7 inches in 2 hours.

Band of deep tropical moisture has pushed into the region from the SSW overnight along with a coastal trough that is lining up nicely with the current activity pushing out of the Gulf of Mexico. Radar returns show additional activity developing over the Gulf, but the short wave that helped to focus the heavy rainfall this morning is moving out of the area…so we should see a break through the mid to late morning hours.

Another weaker short wave will approach this afternoon and with surface heating will likely see additional showers and thunderstorms develop. Storm motions should be 10-15mph toward the NW, but any storm that anchors could produce very heavy rainfall in a short period of time.

Forecast for Saturday is more questionable as there does not appear to be any focus for storm development except heating and warm air advection. Will not rule out some sort of disturbance in the SW flow aloft that may ripple across the area and set off more scattered showers and thunderstorms.

Cold front will move across the region Saturday night and Sunday with showers and thunderstorms likely. Additional isolated heavy rainfall will be possible along this boundary as it crosses the region. Storm motions should be fast enough to preclude any flooding, but will have to keep an eye on any training cells.

Moisture levels clearly support excessive rainfall as shown this morning over S Harris/N Galveston Counties with 4-6 inches in an hour or two. Moisture levels will remain high today, then begin to decrease some on Saturday. Still a little nervous with the decent low level inflow, hard to time (and see) disturbances aloft, and potential for cells to anchor. Not expecting any sort of widespread flooding concerns, but isolated is possible.
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CrashTestDummy
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We got 1.88" overnight. Glad we're just a bit southwest of the big rain!!
Gene Beaird,
Pearland, Texas

"You can learn a lot from a Dummy."
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jasons2k
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Well, now that the trees and grass need some rain again, I see the weather Gods are up to their usual tricks again. The line split in half just as it approached me. Just some sprinkles here. Surprise Surprise....
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srainhoutx
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10202017 mcd0894.gif
MESOSCALE PRECIPITATION DISCUSSION 0894
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
956 AM EDT FRI OCT 20 2017

AREAS AFFECTED...SERN TX

CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE

VALID 201351Z - 201800Z

SUMMARY...PERIODS OF TRAINING HEAVY RAIN ARE EXPECTED TO CONTINUE
THROUGH THE REMAINDER OF THE MORNING ACROSS PORTIONS OF SERN TX.
SOME EASTWARD MOVEMENT TOWARD SWRN LA IS POSSIBLE BY 18Z WITH
LOCAL 4-6 INCH TOTALS NEAR THE COAST.

DISCUSSION...WATER VAPOR IMAGERY SHOWED A SHORTWAVE TROUGH MOVING
INTO OK AS OF 13Z WITH THE TAIL END OF THE SHORTWAVE EXTENDING
TOWARD THE MIDDLE TX COAST. WINDS ALOFT WERE DIFFLUENT AHEAD OF
THE TROUGH AXIS OVER ERN TX LIKELY ADDING TO VERTICAL LIFT THROUGH
THE COLUMN. LOOPS OF INFRARED IMAGERY SINCE 00Z ALSO HINTED AT
PERHAPS A WEAK VORTICITY MAX THAT TRACKED NORTH FROM THE GULF INTO
SERN TX TIED TO A BURST OF CONVECTION EARLIER THIS MORNING.
OBSERVED RAINFALL RATES TIED TO THAT BURST FROM 10Z IN NRN
GALVESTON COUNTY WERE ABOUT 5 IN/HR COINCIDENT WITH GPS
PRECIPITABLE WATER VALUES OF 1.8 TO 2.0 INCHES. KLCH AND KHGX
RAINFALL ESTIMATES SHOWED 3-4 INCHES HERE AND CONTINUE TO BE
UNDERDONE WITH ONGOING RAINFALL OVER THE REGION.

RAP ANALYSIS WINDS AT 850 MB WERE SIMILAR TO VAD WIND PLOTS FROM
KHGX...TIAH AND KLCH...THOUGH THE RAP WIND SPEEDS WERE A BIT
WEAKER THAN OBSERVATIONS SUGGESTING STRONGER CONVERGENCE THROUGH
13Z. FLOW WAS CONVERGENT IN THE LOW LEVELS HELPING TO FOCUS A
BROKEN LINE OF CONVECTION THAT EXTENDED FROM JUST EAST OF
GALVESTON BAY INTO THE GULF OF MEXICO.

SHORT TERM FORECASTS FROM THE RAP SHOW VERY SLOW MOVEMENT TO THE
TAIL END OF THE SHORTWAVE TROUGH AXIS OVER ERN TX WHICH KEEPS THE
AREA UNDER DIFFLUENT FLOW THROUGH AT LEAST 18Z. THE RAP ALSO SLOWS
A CONTINUATION OF THE LOW LEVEL CONVERGENCE AXIS WHICH IS EXPECTED
TO HELP CONTINUE A FOCUS FOR ADDITIONAL CONVECTION THROUGH THE
MORNING. IT APPEARS THE RAINFALL AXIS WILL NOT DRIFT BACK TO THE
WEST...BUT THE MPD THREAT AREA COVERS THE EASTERN HOUSTON METRO TO
ACCOUNT FOR POSSIBLE WOBBLES IN THE AXIS. THE NORTHWARD EXTENT OF
HEAVY RAINFALL SHOULD BE LIMITED BY REDUCED INSTABILITY TO THE
NORTH...FOCUSING THE GREATEST THREAT FOR AN ADDITIONAL 4-6 INCHES
TO WITHIN 50-75 MILES OF THE COAST.

OTTO

ATTN...WFO...HGX...LCH...
Carla/Alicia/Jerry(In The Eye)/Michelle/Charley/Ivan/Dennis/Katrina/Rita/Wilma/Humberto/Ike/Harvey

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jasons2k
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Key sentence:

IT APPEARS THE RAINFALL AXIS WILL NOT DRIFT BACK TO THE
WEST...BUT THE MPD THREAT AREA COVERS THE EASTERN HOUSTON METRO TO
ACCOUNT FOR POSSIBLE WOBBLES IN THE AXIS.
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srainhoutx
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srainhoutx wrote:A very comfortable start to the day with the low 60's across NW Harris County and the upper 50's further North. We should be slightly below climatology temperature wise today across our Region before the winds shift East and then to the SE with an onshore flow into the weekend with warm temperature returning. Will pencil in our next front late Sunday into next Monday.

Looking at the longer range, I am seeing some indications of a possible pattern change as a strong Western Pacific Typhoon re curves into the Northern Pacific and buckles the mainly zonal flow we have seen throughout the Summer. It is not unusual to see this sort of Hemispheric Pattern shift as we get deeper into October. If the ECMWF solution is correct, we may see much cooler air build across the Arctic and Siberia. If the jet stream buckles as some of the longer range deterministic and ensemble guidance suggest, we may see some of that "colder air" arrive in about 20 days or so..' or near Halloween. We will see.
Typhoon Lan is a very large Typhoon (over 1000 miles in diameter) and close to a Super Typhoon or near CAT 5 Status in the Atlantic Basin as it approaches Tokyo in about 24 to 36 hours and will move quickly ENE and transition into a pattern changing Extra Tropical Cyclone in the Bering Sea. The overnight guidance continues to advertise some significant Artic and Canadian air will drop South into the Central Untied States and into our Region. It almost appears that the guidance is attempting to sniff out a blocking regime with a big Alaska High Pressure cell and another big High Pressure cell near Greenland. The 850mb freezing line appears to be very close to College Station/Huntsville/Lake Livingston next Saturday suggesting 2 meter temperature or at the surface where we live may approach the low 40's for morning lows possibly the mid to upper 30's in outlining typical colder spots next weekend with daytime highs struggling to get out of the 60's for highs. We will need to monitor the trends this week to see if those model temperature outlooks are close to being accurate at this range. There is the possibility of yet another strong Canadian Front arriving Halloween Night or sometime on the 1st of November. More on that later.
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10212017 00Z ECMWF EPS 168 ecmwf-ens_z500aNorm_namer_8.png
10212017 00Z ECMWF EPS 168 ecmwf-ens_T850a_namer_8.png
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cperk
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Thanks srainhoutx for giving us cold weather lovers hope. :)
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DoctorMu
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Ensemble is now picking up the Chill next weekend:


Image
unome
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http://www.weather.gov/hgx/
https://twitter.com/iembot_hgx

https://www.facebook.com/NWSHouston/pho ... =3&theater

US National Weather Service Houston-Galveston Texas

A cold front and associated line of thunderstroms is moving southeast at 35 to 40 mph. Brief heavy rain and wind gusts to 35 mph with these storms. Should be in the Houston around 8 AM.

Temperatures are falling 15 to 20 degrees behind the front. The temperature in Huntsville fell from 76 degrees to 62 degrees in just 20 minutes.


Image

Area Forecast Discussion
National Weather Service Houston/Galveston TX
627 AM CDT Sun Oct 22 2017

.AVIATION...
The leading edge of the thunderstorms were moving into KUTS and KCLL at 1115Z. Winds were gusting to 34 knots at KUTS. The storms should arrive at KCXO by 12Z, KIAH around 13Z, KHOU and KSGR around 1330Z, and KLBX and KGLS between 14Z and 15Z. Both the Texas Tech and the HRRR move the area of storms off the coast by 17Z to 18Z.

Impacts ahead of the storms will be patchy fog, occasionally dense. As the storms arrive, wind gusts of 25 to 30 knots will be possible along with ceilings IFR or lower and visibility restricted to 2 nm or less due to heavy rain. An hour or two of lighter rain will follow the initial period of heavier rainfall. VFR conditions will develop during the mid to late morning period.

Later this afternoon after the cold front passes through each site, expect northwest to north winds will gust from 20 go 25 knots at most sites. These should taper off during the early evening. Along the coast, KGLS should see wind gusts persisting through much of the night.

40
BlueJay
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We are getting a taste of that system. Winds are gusty and temperature is dropping. I hope we get a bit of rain.
unome
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thunder rumbling in the distance https://atmo.tamu.edu/ciams/lma/

https://twitter.com/iembot_hgx/status/9 ... 5548177410
Special Weather Statement
National Weather Service Houston/Galveston TX
728 AM CDT SUN OCT 22 2017

TXZ179-199-200-213-214-221315-
Chambers TX-Liberty TX-Polk TX-Harris TX-Montgomery TX-
728 AM CDT SUN OCT 22 2017

...SIGNIFICANT WEATHER ADVISORY FOR EASTERN MONTGOMERY... NORTHWESTERN CHAMBERS... LIBERTY... SOUTHEASTERN POLK AND EASTERN HARRIS COUNTIES
UNTIL 815 AM CDT...

At 727 AM CDT, Doppler radar was tracking a strong thunderstorm 7 miles southeast of Cleveland, moving southeast at 55 mph.

Winds in excess of 40 mph will be possible with this storm.

Locations impacted include...
Liberty, Cleveland, Dayton, Mont Belvieu, Old River-Winfree, Ames, Daisetta, Hardin, Plum Grove, Kenefick, Devers, North Cleveland, Dayton Lakes, Tarkington Prairie and Moss Hill.

https://radar.weather.gov/ridge/lite/N0S/HGX_loop.gif
Image
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Katdaddy
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Special Weather Statement
National Weather Service Houston/Galveston TX
825 AM CDT SUN OCT 22 2017

TXZ200-213-214-238-221445-
Chambers TX-Liberty TX-Galveston TX-Harris TX-
825 AM CDT SUN OCT 22 2017

...SIGNIFICANT WEATHER ADVISORY FOR NORTHERN GALVESTON...CHAMBERS...
SOUTHEASTERN LIBERTY AND SOUTHEASTERN HARRIS COUNTIES UNTIL 945 AM
CDT...

At 824 AM CDT, Doppler radar was tracking strong thunderstorms along
a line extending from near Fannett to Channelview. Movement was
southeast at 30 mph.

Winds in excess of 40 mph will be possible with these storms.

Locations impacted include...
Eastern Pasadena, northeastern League City, Baytown, Texas City, La
Porte, Deer Park, Dickinson, La Marque, Seabrook, Beach City, Kemah,
Cloverleaf, Channelview, Highlands, northeastern Clear Lake, Barrett,
Nassau Bay, Mont Belvieu, Taylor Lake Village and El Lago.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Frequent cloud to ground lightning is occurring with these storms.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.
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unome
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it was a good rain here, but some areas without power, likely from lightning

http://gis.centerpointenergy.com/outagetracker/
As of 10/22/2017 8:36:50 AM, CenterPoint Energy reporting 15105 Customers without lights. Next update in 5 Minutes.
Electric Lizard
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The clouds are already breaking here in Washington county
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srainhoutx
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Nice Monday morning in NW Harris County where temperature has dropped to 51F as of 7:00 AM. A secondary surge of colder and drier air arrives overnight into early tomorrow which should allow for even cooler temperatures, particularly daytime highs which may struggle to get out of the 60's tomorrow and Wednesday.

Yet another front arrives late Friday/early Saturday extending our string of Chamber of Commerce Weather into next weekend.
Carla/Alicia/Jerry(In The Eye)/Michelle/Charley/Ivan/Dennis/Katrina/Rita/Wilma/Humberto/Ike/Harvey

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MontgomeryCoWx
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Adios Summer, you evil, disgusting monster!
Team #NeverSummer
BlueJay
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I miss summer.
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