October 2015 - Severe Storms/Moderate Risk Excessive Rainfal

[srainhoutx]

While the weekend will bring a shot of cooler and drier air into the Region, the overnight MJO and Tropical Cyclone Genesis Probabilities are 'sniffing' out the tropical convection across the NW Caribbean extending into the Gulf of Tehuantepec. The National Hurricane Center is monitoring an area of disturbed weather S and SE of the Gulf of Tehuantepec moving toward the West Coast of Mexico giving it a 50% chance for development by day 5. Enjoy the weekend and we will continue to monitor the potential weather maker across our Region for next week. It's been a while since we have really had anything of note to talk about, but that may be changing...

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[DoctorMu]

Tropical lemonade would be best. This time of the year full-blown TS/H usually slide east of Texas, and yields the risk of hotter, windy conditions under the ULH.

Hoping for a hot mess.

Aw nuts, another TC like Bill!

Uh, what kind of storm do you get at 996 MB?

Usually a tropical storm. That or weaker would be our best shot at significant rain

Hopefully the system remains disorganized and allows significant moisture into the area. A stronger system would likely turn more NNE/NE and head for the central Gulf coast keeping TX on the dry side. GFS QPF is certainly worth noting with amounts of 4-6 inches of a good part of the area by next weekend. Upper system looks slow moving and will likely lead to prolonged rain chances Wednesday-next week.

[stormlover]

we now have a invest

[srainhoutx]

we now have a invest

92L has been designated by the National Hurricane Center.

TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
200 PM EDT FRI OCT 16 2015

For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

1. A broad area of low pressure located in the Gulf of Honduras
associated with a tropical wave is producing a large area of
cloudiness, showers, and thunderstorms across portions of the
northwestern Caribbean Sea. Land interaction is expected to preclude
significant development of this system during the next day or so
while it moves slowly west-northwestward across the Yucatan
Peninsula. However, some limited development is possible on Sunday
or Monday if the system emerges into the Bay of Campeche. Regardless
of tropical cyclone formation, this system could produce heavy
rainfall across portions of Belize and the Yucatan Peninsula through
the weekend.
* Formation chance through 48 hours...low...10 percent
* Formation chance through 5 days...low...20 percent

Forecaster Brennan

[stormlover]

euro wow lol


http://www.tropicaltidbits.com/analysis ... 0&ypos=255

[srainhoutx]

12Z Global model recap:

GFS: moves a surface low inland S of Corpus heading generally NE

Euro: develops a surface low just S of Brownsville heading generally ENE into the Beaumont/Lake Charles area next weekend.

[srainhoutx]

The Friday afternoon Updated Climate Prediction Center Day 6 to 10 precipitation Outlook continues to advertise a very wet pattern developing.

[srainhoutx]

Afternoon briefing from Jeff regarding our pattern change and 92L:

Potentially rare tropical system in the western Gulf of Mexico next week.

Yep it is mid October, but global forecast models are indicating the potential for a surface low pressure system to develop over the southwest/western Gulf of Mexico next week. This suggestion of tropical systems in the western Gulf has been highlighted a couple of times this hurricane season and thus far only Bill has resulted. Additionally, since 1851 only 1 tropical system has struck the state of Texas after October 16th…so any threat would be very rare. However…even if the calendar says October…the pattern is somewhat like September currently.

Two areas of disturbed weather are clearly noted on satellite images this afternoon with one over the SW Caribbean Sea and the other over the open Pacific waters south of the Mexican coast. The Pacific system appears well on its way to developing into a tropical system and will drift WNW then NW toward the coast over the weekend. The SW Caribbean Sea is elongated and moving inland over central America, but is expected to emerge in the southern Gulf of Mexico by late this weekend. Many times global models struggle with tropical development in this region and which side of Mexico the system forms and this may certainly be the case this time as well…but current observation suggest the Pacific system will develop first. Normally such systems would move westward, but this time of year with stronger troughs moving across the US, it is possible for such a system to be brought northward over MX and into the Gulf of Mexico on a rapid northward track. This seems at least possible next week given the formation of a deep layer trough over the SW US.

Another possible outcome is that a coastal trough forms over the western Gulf and never closes off into a closed surface low…that is not what the models are showing at the moment, but what has happened in the past this time of year.

For now will see what happens over the weekend…but feel rain chances will certainly rise significantly toward the middle of next week and remain high into next weekend. Will probably also need to watch tides starting early next week with sustained ENE flow and long fetch over the northern Gulf. Forecast confidence is fairly low given any tropical system passing inland to our west would bring much higher rainfall totals as well as other impacts while one passing to our east would result in lower rainfall chances. Much also depends on how any system might interact with the upper level trough to our west.

[tireman4]

This could be an interesting week coming up...very interesting....

[davidiowx]

This could be an interesting week coming up...very interesting....

Yes indeed it does. It will be interesting to see what happens later this weekend and into early next week

[Paul Robison]

This could be an interesting week coming up...very interesting....

Is history about to repeat itself?

https://en.wikipedia.org/wiki/1949_Texas_hurricane

[srainhoutx]

I am not seeing any real change in the sensible weather forecast through at least Tuesday. A very nice and cooler weekend is on tap making for an excellent weekend for Wings Over Houston at Ellington Field. Temperatures will be very pleasant, but wildfire dangers still exist throughout the weekend.

Changes are lurking next week, but a lot of uncertainty remains. The eventual evolution of the cutoff upper low meandering over Northern Mexico and the Desert SW as well as moisture from the Eastern Pacific at the mid and upper levels crossing Mexico with embedded disturbances riding the noisy sub tropical jet ENE to NE. The broad area of disturbed weather associated with the monsoonal trough across the NW Caribbean Sea into the Gulf of Tehuantepec is festering this morning, but so far no signs of organization is occurring either side of Central America.

The most likely solution appears to be the possible development of a weak surface low in association with a Coastal Trough mid next week enhancing rain chances across Coastal Texas. The wild card will be just how quickly the longwave Western trough begins to trek E and how strong the cold ridge of High Pressure across the Appalachian Mountains remains anchored. It will likely take until Monday at the very least before we will have any real idea how next week unfolds, so get out and enjoy the Chamber of Commerce Weekend!

[Paul Robison]

I am not seeing any real change in the sensible weather forecast through at least Tuesday. A very nice and cooler weekend is on tap making for an excellent weekend for Wings Over Houston at Ellington Field. Temperatures will be very pleasant, but wildfire dangers still exist throughout the weekend.

Changes are lurking next week, but a lot of uncertainty remains. The eventual evolution of the cutoff upper low meandering over Northern Mexico and the Desert SW as well as moisture from the Eastern Pacific at the mid and upper levels crossing Mexico with embedded disturbances riding the noisy sub tropical jet ENE to NE. The broad area of disturbed weather associated with the monsoonal trough across the NW Caribbean Sea into the Gulf of Tehuantepec is festering this morning, but so far no signs of organization is occurring either side of Central America.

The most likely solution appears to be the possible development of a weak surface low in association with a Coastal Trough mid next week enhancing rain chances across Coastal Texas. The wild card will be just how quickly the longwave Western trough begins to trek E and how strong the cold ridge of High Pressure across the Appalachian Mountains remains anchored. It will likely take until Monday at the very least before we will have any real idea how next week unfolds, so get out and enjoy the Chamber of Commerce Weekend!

The Euro has demoted the "potential tropical system" to a weak surface low, at least, according to today's model run.

p.s. did anyone read the wiki article about the Great October Texas hurricane of 1949. IS history about to repeat itself?

[DoctorMu]

This could be an interesting week coming up...very interesting....

Is history about to repeat itself?

https://en.wikipedia.org/wiki/1949_Texas_hurricane

1949 hurricane was a late Sept. event...a scenario very rare on the Texas coast in mid to late October.


The forecast looks tricky indeed. A meandering morass could be the soaker we need. Fingers crossed.

[srainhoutx]

The overnight Global computer guidance is slowly coming into agreement that Texas and our surrounding Region is headed toward a significant pattern change beginning Tuesday afternoon extending into next weekend.

A combination of a very deep longwave trough that features a closed 500mb low at the base of the trough over Northern Mexico and Southern Arizona along with a very unsettled area of lowering pressure across the Gulf of Tehuantepec extending East into the NW Caribbean Sea and a stalling frontal boundary across Central Texas mid week offer a recipe for a potential very heavy rainfall event for much of the Lone Star State.

Moisture levels across the Bay of Campeche are running greater than 2.5 inches this morning with even deeper moisture across the Eastern Pacific extending East into Central America and the NW Caribbean Sea. A broad area of low pressure at the surface associated with a monsoonal trough looks to begin surging North across Central Mexico and the Western Gulf on Tuesday. Moisture levels are expected to reach and possibly exceed 2 standard deviation above normal for this time of year across our Region Wednesday into Thursday. Embedded disturbances rotating beneath the Western trough from a very noisy sub tropical jet as well as a Coastal trough along the Lower and Middle Texas Coast suggest some locations may receive 5 to 7 inches of heavy rainfall with isolated higher amounts nearing 10 inches, if the Western trough meanders longer than expected. This is a complicated and complex forecast challenge, so expect day to day changes as the week ahead unfolds. Next Friday and Saturday could be particularly stormy with all modes of severe weather possible. More later on this developing weather situation.

[srainhoutx]

The 12Z GFS through 180 hours suggests the longwave trough and at least 2 shortwaves close off over Northern Mexico and Southern Arizona with a surface low/trough developing along the Lower Texas/NE Mexico Gulf Coast. It is a bit interesting to see the GFS now agreeing with the overnight Euro that a weak surface low meanders near/offshore of Galveston next weekend further enhancing the extended heavy rainfall threat through next Sunday as the longwave trough lingers to our West.

EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1143 AM EDT SUN OCT 18 2015

VALID 12Z WED OCT 21 2015 - 12Z SUN OCT 25 2015


THE MODELS ARE IN REASONABLE AGREEMENT ACROSS THE UNITED STATES
THROUGH DAY 5, WITH UNWIELDY DIVERGENCE BLOOMING THEREAFTER. EVEN
AMONG THE VARIOUS ENSEMBLE MEANS--WHICH INFORM THIS FORECAST
PACKAGE--THERE ARE MEANINGFUL DIFFERENCES LATE IN THE PERIOD. THE
MOST CONTENTIOUS DIFFERENCES ARE OFF THE WASHINGTON COAST DAYS 6
AND 7, WHERE THE DEGREE OF UNDERCUTTING IN RELATION TO A
REEMERGING BLOCKING HIGH NEAR THE YUKON IS MOST PRUDENTLY
ADDRESSED BY A BLEND OF THE ENSEMBLE GUIDANCE. BY FAR, THE BIGGEST
SENSIBLE WEATHER THREAT THIS PERIOD IS RAINFALL, WITH A PLUME OF
TROPICAL MOISTURE AIMED AT TEXAS AND POINTS NORTHWARD THROUGH THE
GREAT PLAINS. THE JURY IS STILL OUT ABOUT WHETHER A FULL-FLEDGED
TROPICAL SYSTEM WILL EMERGE FROM THE FAR WESTERN GULF OF MEXICO.


CISCO

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[srainhoutx]

Afternoon briefing from Jeff:

Potentially impactful weather event for the end of the week into next week for much of the region.

Upper level pattern will undergo significant changes this week with the upper level ridge which has dominated our weather for the last several weeks breaking down and being replaced with a strong upper level trough over the SW USW. An eastern Pacific tropical system will likely develop along the Mexican coast and move slowly NW then NNW and become captured into the trough over the SW US resulting in extensive moisture advection northward from the eastern Pacific. Large mass of deep tropical moisture over the Bay of Campeche will be released northward starting Monday arriving into SE TX on Tuesday. Moisture deepens into Friday and Saturday peaking near record levels for late October. Upper level trough will edge slowly eastward over this week allowing increasing lift aloft. At the same time models continue to attempt to develop some sort of western Gulf of Mexico surface low (possibly tropical or possibly hybrid) and bring this feature into the TX coast Friday night into Saturday. Will favor the less defined GFS solution with this feature over the more defined and stronger ECMWF. A tropical system in the NW Gulf in late October would be rare and think a strong coastal trough or frontal low is more likely. Regardless…impacts will be the same.

Winds are already steady ENE 15-20mph across the coastal waters this morning and will remain steady and slowly increase through the week as pressures lower over the western Gulf and help increase the pressure gradient. Moisture will begin to arrive into the area Tuesday and spread inland/northward on Wednesday. Will go ahead and include 20-30% rain chances Tuesday and 30-40% Wednesday then much more significant chances Thursday-Saturday. Friday and Saturday continue to look extremely wet with increasing potential for prolonged and sustained significant training rainfall event from deep S TX into the coastal bend and SE TX. Model QPF in the Friday-Saturday period continues to be on the heavy to excessive side and profiles support strong southerly flow with near record moisture levels all pointing toward high rainfall totals. Still some disagreement on where exactly the heavy rains will setup and how much…but current model totals would certainly be concerning even with the current dry conditions and would likely result in both flash flooding and possible river flooding.

Marine/Coastal:
Another concern will be increasing marine hazards which will include building seas and potential coastal flooding. Deepening coastal trough/low pressure off the NE MX coast late week will combine with strong high pressure over the SE US to produce a strong E to ESE gradient across nearly the entire northern Gulf of Mexico. Winds will increase into the 15-25mph range on Wednesday and then 20-40mph on Friday. GFS based Wavewatch III shows 8-10 ft seas mid week building to 13-15 ft by late week. Tides will be elevating due to long fetch E winds which is a favorable tidal transport wind toward the upper TX coast. Combination of strong winds and building seas will ramp tides to 1-2.5 ft above normal by Thursday and possibly even higher by Friday. Total water level when combined with possible storm surge could approach 3.5-4.5 ft by Friday which is near our critical flood thresholds on Bolivar, the west end of Galveston, and the west side of Galveston Bay. Will need to keep a close eye on the tides this week as this will be an extended period of coastal impact and could lead to significant beach erosion.

Fire Weather:
Before the big change in the pattern this week…fire weather conditions will remain elevated to near critical especially between noon and 600pm today and Monday NW of US 59. RH will fall into the 15-30% range each afternoon with NE to ENE winds of 10-20mph. Fuels remain critically dry, but thus far fire that started on Saturday were able to be brought under control quickly…with most averaging less than 10 acres.

Hidden Pines Fire:
No significant changes in this complex since Friday with fire lines holding and acreage nearly the same 4582. Thus far 50 structures have burned and over 200 were saved. No additional structures have been lost since Thursday and ground crews have made extensive progress with air support on maintaining fire lines with crews working hot spots deeper within the containment lines. Fire will likely exhibit sporadic activity until wetting rainfall fully ends the threat later this week.

[unome]

NHC's 2 PM 5-day - I hope WPC doesn't seriously downgrade our rain chances, I'm so sick of watering the lawn...

ZCZC MIATWOAT ALL
TTAA00 KNHC DDHHMM

TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
200 PM EDT SUN OCT 18 2015

For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

1. A weak area of low pressure located inland over southeastern Mexico
just west of Villahermosa is producing disorganized showers and a
few thunderstorms, primarily across portions of the Bay of Campeche.
This system is moving slowly westward to west-northwestward, and
development is unlikely since the low is no longer expected to
emerge over water. The Air Force Reserve Hurricane Hunter aircraft
mission scheduled to investigate the system this afternoon has been
canceled. This system could still produce locally heavy rainfall
across portions of southeastern Mexico and the Yucatan Peninsula
during the next day or two.
* Formation chance through 48 hours...low...near 0 percent
* Formation chance through 5 days...low...near 0 percent

Forecaster Kimberlain

[Rip76]

Our rain chances would have to go down, unless there are other things at play here.

[Cromagnum]

I've given up on my lawn this year. Since mother nature refuses to help, I'm just going to let it die.