December 2015 -Year Ends As One Of Wettest On Record

[MontgomeryCoWx]

Looks coolish on Christmas on the latest...

New Years, while far out, looks cold on the GFS (consistently)...

[srainhoutx]

Has Christmas already flipped back again to warm??

The weather pattern remains very volatile across North America with a very deep low pressure anomaly (Western trough) situated from the Pacific NW into the Great Basin/Desert SW into the Rockies. Such a pattern supports below normal temperature with a very unsettled and stormy Christmas Holiday period. A very strong SE Ridge is expected to keep areas along and East of the Mississippi River Valley very warm with temperature anomalies around 25F to 30F above normal. There is no sign of winter or significant changes across those Region for the foreseeable future. What that means for travelers heading East, chances of rain with a noisy and active subtropical jet feeding moisture from the Pacific as well as Gulf moisture streaming inland ahead of a stalled frontal boundary.

For us here is Texas, a stationary front looks to be situated along the I-35 Corridor with embedded shortwaves (upper air disturbances) riding beneath the Western trough as well as along the sub tropical jet. Cloudy and possibly showery weather looks to be in the cards for South, Central, SE, East Texas into Louisiana for Christmas. That said and as Brooks mentioned in his post and what we have been mentioning for about the past week to 10 days on this board is the potential for a very strong and possibly significant storm system developing right after Christmas in the days leading up to the New Years Eve timeframe. If the ensembles are correct as well as the teleconnection indices rolled forward in time to around the New Year, the pattern certainly appears capable of bring much colder and stormier weather to Texas. Does that mean we are seeing and Arctic Outbreak? No. Is such a pattern capable of delivering wintry mischief to Texas? there is that possibility. Remember true Arctic Outbreaks are typically extreme cold and dry. The current pattern with a noisy subtropical jet streaming overhead with clouds and embedded disturbances typically spell wet and unsettled weather for Texas. With some indications that a big Ridge pumping up into Alaska from the N Central Pacific possibly dislodging pieces of the very cold air (-30 to near -50C in some locales) that has been building over Alaska as well as Western Siberia and Eurasia, we will need to closely monitor for a deepening Western trough that digs well into Mexico into the Front Range of the Rockies as well as the Central and Southern Plains. Patience is advised for those looking for our real Winter pattern to arrive in Texas. It's looking like as we turn the calendar to a New Year, we will look back at these pleasant temperatures and lower utility bills favorably and warm weather lovers will be longing for Spring and Summer possibly well into March and possibly into April. Stay tuned.

[wxman57]

Here's a meteogram from the latest GFS run. Low 50s Christmas morning followed by a steady climb to near 80 on the 26th. Significant cold front by the 28th, knocking the low down into the 30s. Still no freeze indicated through December.

[MontgomeryCoWx]

12z still looks coolish for Christmas and cold leading up to NYE and thru the 3rd (la la land)....

[brooksgarner]

I've enjoyed today's discussion and agree that the big question for next week's Christmas forecast remains... GFS or EURO? Hot or seasonal? I tend to think that the EURO because we've got six Rossby waves in the northern hemisphere (it's an amorphous six, because it's soon to be only five) and that has to decrease, for stability ... One of them should collapse into another -- merging in a sense -- and I think it'll be the one near Japan merging/joining/fading-into the western trough... That scenario would favor the EURO's deeper western through solution in 7-8 days... That would give us highs near 80°F over Christmas.

So is this all teleconnection gobbly gook or brilliant foresight? (Haha! I'm not sure myself. This is a tough 7-day forecast.)

It's a changing forecast and it'll be interesting to see how it all shakes out. It's a chaotic system.

[srainhoutx]

Chilly temperatures this morning will give way to a quick warm up as the High Pressure Ridge quickly moves off to the East today and pressures begin to fall to the West in advance of another shortwave advancing across Mexico brings a return flow off the Gulf. Clouds and moisture increase further tomorrow as a Coastal trough begins to organize and rain chances increase particularly along the Coastal tier of Counties of SE Texas and Louisiana. There is a Marginal chance for thunderstorms Sunday night into Monday as the upper air disturbance moves by, but most locations will only experience light to moderate rain with this fast moving system.

As we head toward Christmas Eve, temperature begin to rise to near record levels as a very potent storm system crashes ashore in the Pacific NW and drops SSE into Arizona/Northern Mexico on Christmas Day. There is a lot of very cold Polar Maritime air associated with this storm, particularly in the mid to upper levels which raises an eyebrow. The overnight guidance is slowly coming into somewhat better agreement that late next weekend into the early day of the last week of 2016 could be very stormy, so we will need to monitor further developments and Christmas Week progresses. If the very Southern track and potentially negative tilted upper trough and cold core upper low does indeed verify, we could be dealing with a myriad of weather worries a week from Sunday into the 28th/29th across our Region. Stay tuned during the hectic Christmas Holiday travel period for further updates regarding that storm system.

[jeff]

Models continue to support very impressive moisture levels once again across the area both early next week and toward the end of next week and next weekend. PWS of 1.8-2.0 inches in mid to late December is almost unheard of...in other words summer time moisture with winter time dynamics. This is a function of the continued warmth of both the Gulf and overall warmth of the air masses (warm air can hold more moisture) and the connection of the mid and upper sub-tropical flow enhanced by the warm phase ENSO. With grounds already very soggy over the region and lakes/rivers running high the next two weeks could bring a fairly serious flood threat especially to area rivers as at least of couple of southern stream storms systems interact with this copious moisture that will be in place.

[unome]

from http://www.cpcpara.ncep.noaa.gov/ , Climate Prediction Center's 3-14 day Hazards outlook discussion:

US Hazards Outlook
NWS Climate Prediction Center College Park MD
300 PM EST December 18 2015

Synopsis: A series of North Pacific storm systems are predicted to affect the entire southern coast of Alaska and the western contiguous U.S. during this Outlook period. Several low pressure systems are also forecast to bring widespread precipitation to the eastern third of the Lower 48 states, especially in the few days preceding Christmas. Most of the precipitation is expected to be off the East Coast on Christmas Day. Over the ensuing few days, relatively cold air is expected to prevail across the western contiguous U.S. and Alaska, while in the eastern contiguous U.S., temperatures are forecast to be unusually mild for this time of year.

Hazards

Periods of heavy precipitation for western Washington, western Oregon, and northern and central California, Mon-Thu, Dec 21-24.
Heavy rain for coastal portions of central and southern California, Wed-Thu, Dec 23-24.
Heavy rain from the Gulf Coast northeastward to the mid-Atlantic and southern New England, Mon-Tue, Dec 21-22.
Heavy rain for the Southeast, Wed-Thu, Dec 23-24.
Heavy snow for the northern Rockies, Mon-Tue, Dec 21-22.
Periods of heavy snow for parts of Idaho, Wyoming, Nevada, Utah and Colorado, Mon-Thu, Dec 21-24.
High winds for coastal sections of both Washington and Oregon, and coastal northern California, Mon-Tue, Dec 21-22.
High winds for the Aleutians, Alaska Peninsula, and Bristol Bay area, Mon-Tue, Dec 21-22.
High Significant Wave Heights for the Aleutians, Alaska Peninsula, and Bristol Bay area, Mon-Tue, Dec 21-22.
Flooding possible, likely or occurring in western Oregon, the Midwest, and eastern Texas.
Slight risk of much below-normal minimum temperatures for nearly all of Alaska, Sat-Mon, Dec 26-28.
Slight risk of much below-normal minimum temperatures from the Rocky Mountains westward to the Pacific Coast, Sat-Sun, Dec 26-27.
Moderate risk of much below-normal minimum temperatures for central and eastern Alaska south of the Brooks Range, including the Panhandle, Sat-Mon, Dec 26-28.
Severe Drought across Puerto Rico, Pacific Northwest, California, Northern Great Basin, Central Great Basin, Northern Rockies, and Southwest.

Detailed Summary

For Monday December 21 - Friday December 25: A very energetic and amplified circulation pattern is expected to contribute to widespread areas of storm activity across southern Alaska and the CONUS during the next two weeks. The frequent passage of cyclonic systems is expected to result in periods of heavy precipitation (low elevation rain, high elevation snow) to western Washington, western Oregon, and portions of northern and central California, including the Sierras. Precipitation amounts of 4-10 inches (liquid equivalent) are projected for much of this region from December 21-24. Areas of heavy rain are anticipated across coastal sections of central and southern California (2.0-2.5 inches and 1.0-1.5 inches, respectively) on December 23-24. High winds (about 30-35 knots) may affect coastal sections of both Oregon and Washington, and coastal northern California from December 21-22. Farther inland, heavy snow (liquid equivalent of 1.5-2.0 inches) are expected in the northern Rockies. Periods of heavy snow (liquid equivalent of 2.5-5.0 inches) are forecast in portions of the north-central and central Rockies, including the Wasatch Range in central Utah.

During this period, an area of heavy rain is predicted from the Gulf Coast northeastward across the mid-Atlantic and southern New England on December 21-22. About an inch of rain is anticipated from Virginia to New England, but 4-5 inch amounts are possible near the Gulf Coast from Louisiana to the western Florida Panhandle. Strong to severe thunderstorms are possible in this region, though for the time being no severe weather area is delineated on the map. This is due to uncertainty regarding the potential for prior convection near the Gulf Coast in association with an impulse originating over the subtropical East Pacific. It is currently unclear as to how much the convection associated with this impulse would destabilize the boundary layer in the Gulf Coast region.

Temperatures across much of the eastern CONUS are forecast to be well above-normal during most of this period, ahead of a cold front. On December 24th, Columbus, Pittsburgh, and Raleigh-Durham, for example, may be 20-24 degrees warmer than usual during the day, with high temperatures approaching 60 degrees F in both Columbus and Pittsburgh, and near 70 degrees F in Raleigh-Durham. Much of the eastern quarter of the country is forecast to experience light to moderate rain (0.25-0.75 inch) on December 24th, with heavy rain (1.5-2.5 inches) possible in the Southeast. On Christmas Day, the cold front is expected to be off the northern and mid-Atlantic Coast, with breezy conditions in its wake.

Areas of possible, likely, and imminent/occurring flooding are depicted across the Midwestern states, eastern Texas, and western Oregon due to heavy precipitation that has occurred recently, and is forecast to occur within this period. As flood shapes tend to change frequently, it is recommended that interested persons obtain the very latest river flood stage information at http://water.weather.gov/ahps/rfc/rfc.php

Elsewhere, on December 21-22, a strong cyclonic system is anticipated to bring high winds (45-50 knots) and high significant wave heights (30-45 feet) to the central and eastern Aleutians, the Alaska Peninsula, and the Bristol Bay region.

For Saturday December 26 - Friday January 01: During Week-2, the predicted mid-tropospheric flow pattern continues to feature an amplified trough over the western CONUS and an amplified ridge over the eastern CONUS. According to the CPC Probabilistic Extremes Outlook tool, there is a slight risk of much below-normal temperatures for nearly all of Alaska from December 26-28. There is a moderate risk of much below-normal temperatures for central and eastern Alaska south of the Brooks Range, including most of the Panhandle, during the same three-day period. For the Lower 48 states, there is a slight risk of much below-normal temperatures for most of the western third of the Nation from December 26-27. These areas denote where minimum temperatures are more likely to reach the 15th percentile, or lower, of the historical distribution.

The most recent U.S. Drought Monitor, released on December 17, indicates a small decrease in the coverage of severe to exceptional drought (D2 to D4), from 14.35 percent to 13.12 percent. Some of the more obvious changes from the previous Monitor include a 1-category improvement across portions of the Pacific Northwest, and also in Kansas.

Forecaster: Anthony Artusa

[unome]

the link in the last post can bring you to our West Gulf River Forecast Center's page, once you click on that region - here's their "Quick Brief", which is just awesome, imo - everything you need in one spot

http://www.srh.noaa.gov/wgrfc/HMDmain.php

[srainhoutx]

The overnight guidance continues to advertise a very active and stormy pattern developing as we head toward the New Year. The main concern during the short to medium range continues to be the threat of heavy rainfall and the potential for thunderstorms, some possibly severe including all modes of severe weather during the hectic Christmas Holiday travel period. I am going to look primarily at the week ahead and just beyond Christmas Day in the first section of this update, but will take a look at some indicators of what may be ahead as we turn the calendar into January in the second section of the update.

The week ahead continues to look extremely warm across the Eastern half of the United States and that leads to some confidence of the stormy, possibly severe weather worries from Texas to the Tennessee and Ohio Valley Regions and along the Gulf Coast. Temperature anomalies may well approach +30F compared to normal which raises an eyebrow and certainly erases any chance of a White Christmas for the Red River, Missouri, Middle and Lower Mississippi River Valley into the Ohio River Valley and on East toward the I-95 Corridor. Out West, that pattern continues to advertise a wet, cold and stormy pattern with abundant higher elevation snow which bodes extremely well for the long-term drought those locations have been experiencing.

Our first storm system will arrive tomorrow and continue into Wednesday making for messy travel from the Eastern half of Texas on East. While the severe potential looks somewhat limited with this first storm system, heavy rainfall is a possibility from Dallas to San Antonio and on N and E to the East Coast.

The attachment 12202015 SPC Day 2 day2otlk_0700.gif is no longer available

A brief lull in the weather looks likely locally Christmas Eve, but a very potent storm system is lurking to our West and should begin to organize into a strong Spring like storm system with a surface low organizing along the leeside of the Southern Rockies. Several features are concerning with this particular storm and look to add to our weather worries as they combine.

We have a very active sub tropical jet stream feeding abundant moisture from the Central and Eastern Pacific across Mexico into Texas as well as a Convectively Couple Kelvin Wave near the Dateline, or near and just SW of Hawaii. That ‘pineapple express’ of tropical moisture adds fuel for thunderstorm development as a cold pocket aloft moves across the Desert SW toward the Lone Star State. Unidirectional winds at all level suggest a very legitimate shot as severe weather with the possibility of rotating low topped super cells in the warm sector ahead of the storm. This severe potential is a bit worrisome because to may affect a large geographically area from Texas on East. Along with the threat of severe weather potential is growing concern of heavy rainfall and flash flooding due to already saturated soils and swollen Rivers from previous heavy rainfall events that have plagued our Region since October. We encourage everyone to remain weather aware as the hectic Christmas Weekend approaches.

Looking ahead toward the New Year, there are some indications that another storm system may organize in the days near the first work week of 2016 and this could lead to a significant pattern changes that we have mentioned as January begins. The longer range climate guidance has been rather insistent that a favorable MJO Phase 7/8 mode may be possible which typically shifts the persistent Western trough further East indicating a colder pattern East of the Continental Divide. There also have been very strong signals that the Polar Vortex that has been circular in shape over the North Pole will reposition as it continues to take a beating from power storm systems moving out of the North Pacific into the Bering Sea into the Arctic Circle. We have been noticing the past week via the longer range guidance that a significant shift of the Polar Vortex may well be in the works as well as some warming of the Stratosphere particularly over Eurasia and Western Siberia where temperatures have been very cold with abundant snow cover. In spite of the warm temperature anomalies in Canada, snow continues to fall and that snow cover extends South into the Northern Great Basin, The Rocky Mountains as well as the Great Plains. As the upper jet stream pattern and storm track shifts from the Western US into East of the Rockies, the sub tropical jet looks to continue to be very active as El Nino lessen its grip and moves toward a more neutral state later in the Spring and Summer. While it is way too soon to know the ‘finer’ details, it does appear that a strong potential exists for an onslaught cold weather with a continued unsettled pattern with storm systems tracking South along the I-10 Corridor with moisture streaming inland from a still relative warm Gulf and abundant tropical moisture from the Central and Eastern Pacific Ocean.

[wxman57]

Looking like a warm Christmas (upper 70s). No sign of any really cold weather through the first week of January. I see no indications of a significant pattern shift.

[Ptarmigan]

Christmas Climate for Southeast Texas
http://www.srh.noaa.gov/hgx/?n=climate_holidays_xmas

The warmest Christmas tend to occur in La Nina.

[srainhoutx]

A very impressive moisture plume extends from Hawaii across Mexico, Texas and on NE into the Great Lakes in a true El Nino Pineapple Express fashion. A couple of upper air disturbances are moving across the Central United States (one near Missouri and a secondary shortwave near Amarillo) allowing a return flow off the Gulf to become well established. A Pacific cold front is slowly sagging SE from near the Childress area and will pull up stationary somewhere near the I-35 Corridor tonight. Increasing dynamics suggest a severe potential exists mainly along and N of I-10 tonight into tomorrow if the CAP erodes as some of the short term meso guidance suggests. The Storm Prediction Center has issued a Slight Risk for Severe Storms Tuesday for portions of our Region away from the Coastal tier of Counties. Sea fog also looks like a big concern throughout the week as there is no front expected to sweep through the area until possibly next week.

Briefing touching on the Christmas weekend outlook...the only thing that appears to be coming together via all the computer guidance is the growing potential of a cut off cold core low developing somewhere near Southern Arizona/Northern Mexico/New Mexico. Beyond that, the eventual storm track is highly uncertain. That said the trend so far this Fall/early Winter Season has been for cut off upper lows to organize and deepen allowing for leeside cyclogenesis somewhere near the Texas Panhandle and move ENE as the main upper low meanders across Texas. We will look further into what the sensible weather may be regarding that potent storm system as the week unfolds and the guidance becomes a bit more clear on the eventual evolution of where that storm is going. Regardless, it looks wet and stormy across our Region as well as the potential for near record warm temperatures, if the sea fog and low cloud cover doesn't wreak havoc in those temperature forecasts.

[srainhoutx]

Morning briefing from Jeff:

Wet and warm/muggy will be the theme this week including Christmas

Large tap of sub-tropical moisture is overhead this morning with the moisture tap extending from Hawaii to the eastern Great Lakes. The entire eastern 2/3rds of the nation continues to bake in unseasonably warm temperatures and this will continue this week. In fact many locations over the eastern US will likely establish high temperature records on Christmas Day. Locally, the tap of Pacific moisture will remain in place off week and weak to moderate intensity short waves will transverse this flow leading to periods of showers and thunderstorms. One such wave is crossing the area currently leading to strong thunderstorms over Harris and Fort Bend Counties. These stronger storms will be moving eastward this morning into Galveston, Liberty, Chambers, and Brazoria Counties. Meso scale models show a general lull in activity after this first wave this morning, but would not rule out a few showers throughout the day as moisture continues to spill into the area from the SW and increase from the Gulf. Additionally, with the plume coming up from our SW, there could certainly be a disturbance that is not resolved by the models coming across MX which could result in a round of showers…really at any time over the next several days.

A weak…very weak…cool front will move into the region tonight and likely stall along the US 59 corridor early Tuesday. Another short wave trough will approach the area from the SW Tuesday afternoon and the short range models show the air mass becoming increasingly unstable. Could see a round of fairly active weather Tuesday afternoon and evening over the area if the mid level capping erodes. Given how active the radar has become in the last 30 minutes over Harris and Fort Bend Counties, I suspect a fairly active Tuesday afternoon period. Strong to severe storms will be possible along with very heavy rainfall. Best chances for severe weather will be along and north of I-10 along the slowly retreating frontal boundary and where any mid level capping will be weakest.

Wednesday will likely be the best day of the week as the short wave departs and moisture levels fall briefly….possibly allowing a few breaks in the multi cloud decks over the region. Any breaks will allow temperatures to soar into the 80’s which will be close to record highs for late December.

Christmas Eve/Day:
Powerful upper level storm system digs into the SW US and begins to really ramp up moisture return over SE TX starting on the 24th. Expect showers by late in the day and more widespread activity on the 25th. Still some differences on the track of the main storm system and exactly when it moves across TX the weekend after Christmas, but a very active period looks in store with strong/severe thunderstorms and very heavy rainfall at some point the 26/27th. Temperatures will continue to be incredibly warm and humid for this time of year with lows in the 60’s/70’s and highs in the upper 70’s/low 80’s. Overall it looks very warm and muggy with sea fog, low clouds, passing showers and maybe a thunderstorm.

Sea Fog:
Will likely see sea fog develop today over the 0-20NM waters and then plague the coast for the next 3-6 days as onshore flow maintains extremely warm dewpoints over somewhat cool shelf waters. Sea fog will move inland each evening and retreat toward the coast each day around 1000am-noon. Some coastal locations may stay socked in all day any day this week. Fog may certainly be thick enough to cause vessel traffic concerns in Galveston Bay entrance channel and in the mouth of the Houston Ship Channel.

Temperatures:
The entire week will feature well above normal temperatures with lows in the 60’s…maybe 70’s on a few mornings and highs in the 70’s…maybe 80’s on Wednesday and Thursday. These temperatures are running anywhere from 15-20 degrees above normal for this time of year.

Hydro:
Still dealing with run-off from the last few weeks over eastern TX with flood waves moving down the Brazos and Trinity Basins. Flood wave on the Brazos has moved through Fort Bend and much of Brazoria County with the river in recession along much of the basin. Upstream releases will keep the river elevated for the next several days.

On the Trinity the river is above flood stage from south of Dallas to Trinity Bay and flooding will continue for the next several days as flood flows move downstream. Flood gate operations have been ongoing and will continue at Lake Livingston and this is resulting in widespread flooding over portions of Liberty County around Liberty which will continue through the end of the week.

Concern is growing that additional widespread heavy rainfall next weekend could produce large amounts of run-off into already high rivers resulting in more flooding.

[MontgomeryCoWx]

At least New Years looks cold... for the time being!

[cperk]

At least New Years looks cold... for the time being!

The 12oz GFS has snow/sleet for the Houston area for New Years day.Ok i know that's 11 days away,but one can hope.

[snowman65]

At least New Years looks cold... for the time being!

The 12oz GFS has snow/sleet for the Houston area for New Years day.Ok i know that's 11 days away,but one can hope.

Don't EVEN go there....

[cperk]

I'm going there again,the 18oz GFS has the same solution,sleet/snow for Houston.Don't hate the player hate the game.

[MontgomeryCoWx]

If that pans out, it will be more ice than snow... 540 line is 150-200 miles north of us

[Katdaddy]

Dense Fog Advisories across SE, E, and portions of NTX this morning. 20-40% chance of showers and a few strong thunderstorms tonight before a short break from rain chances. SPC has a slight risk area for Portions of N and NE TX tonight while a marginal risk exists for portions of SE and E TX. Mid to upper 70s for highs to continue through the week across SE TX.