January-Foggy Mornings/Cool & Cloudy To The Month

[tx_kingwood32]

40 here in kingwood,think we're suppose to get down to 31 by 6am..hey Ronyan I use to live in clute

[ronyan]

It doesn't look likely we will get to near freezing here tonight. Sitting at 48.4F with a dewpoint of 38.

Already down to 39F here in NW Harris County with dp of 29 ronyan. This likely will be more of N and W of Metro Houston light freeze/frost event versus further S tonight.

Yes that looks probable, here still at 47F near the coast (my location is about 5 miles inland). This next front is much more likely to bring us a freeze all the way to the coast, with a ~1055mb high diving down the plains on Wed & Thurs.

[srainhoutx]

I would caution everyone to wait at see what the next couple of days bring and what the eventual evolution of that weak meandering up low actually does as we near Wednesday evening. The trend today was to slow the progression E toward W Texas/New Mexico by about 6 to 12,hours. Remember it will likely be very dry at the surface with such a cold dense shallow air mass. Then there is the issue of mid/high clouds streaming N E ahead of the upper low as it shears out. The best chance of saturating the llower levels may not happen until late Friday into Saturday as a Coastal wave develops and we are already above freezing. Further E into Louisiana may be a different story as they will be closer to the core of the much colder air.

[srainhoutx]

Freezing temperatures have been reached across much of the Region along and N of the HWY 59 Corridor except in the urban and Coastal Counties where mid to upper 30's have been achieved. The strong Arctic front is scheduled to arrive Wednesday with very gusty winds and even colder temperatures than we are experiencing this morning. We may need winds chill advisories and a Hard Freeze Warning for much of our Region Wednesday night/Thursday morning. Here is a snippet from NWS Houston/Galveston this morning explaining just how cold this Arctic High truly is...

THIS MAY BE THE
STRONGEST HIGH PRESSURE THIS EARLY IN JANUARY IN MORE THAN 30
YEARS. PMDHMD HAD AN INTERESTING SECTION ON POSSIBLE RECORD HIGH
PRESSURE PERIOD. THIS SHOULD PUSH AN ARCTIC FRONT THROUGH
SOUTHEAST TEXAS EARLY WEDNESDAY AND LEAD TO A COLD BREEZY DAY. BE
SURE TO HAVE GOOD COAT HANDY. THE HIGH CONTINUES TO DROP SOUTHWARD
AND THEN TURNS EAST BUT 1036-43MB HIGH SHOULD BE OVER TEXAS THURSDAY
MORNING WHICH SPELLS COLD. WITH THE HIGH STILL TO THE NORTH SETX
MAY STILL HAVE SOME LIGHT NORTHERLY WINDS AND MANY OF THE MODELS
SHOW MID-HIGH LEVEL MOISTURE WRAPPING AROUND AN UPPER LOW NEAR
BAJA SPREADING INTO TEXAS FROM THE SOUTHWEST AND THESE MAY HELP TO
LIMIT THE FALL OF TEMPERATURES TO THE MID 20S DOWN TO AROUND 20
OVER THE NORTHERN AREAS (ROUGHLY NORTH OF COLUMBUS TO CONROE TO
LIBERTY LINE) AND MID 20S TO UPPER 20S SOUTH OF THERE INCLUDING
THE HOUSTON METRO AREA...GALVESTON ISLAND IS PROBABLY GOING TO
REACH 31-33 DEGREES WITH WIND. HARD FREEZE LOOKS LIKELY FOR THE
NORTH WITH THE 20-25 DEGREE TEMPS LASTING IN EXCESS OF 2 HOURS AND
PROBABLY MORE LIKE 6-10 HOURS AND BELOW FREEZING LONGER. TIME FOR
THE WISDOM/EXPERIENCE COMMENT - IF THE HIGH MOVES FASTER RELAXING
THE SURFACE WINDS AND THE MID/HIGH CLOUDS DON`T MATERIALIZE THESE
TEMPERATURES WILL BE TOO WARM BY AS MUCH AS 3-5 DEGREES.


Things may get a bit interesting Friday into early Saturday as the upper low nears West Texas. The GFS is rather aggressive generating QPF as well as developing a Coastal wave near Brownsville/Corpus Christi. Temperatures are borderline even into areas along and N of HWY 105 in SE Texas suggesting freezing rain or sleet may be possible. It is way too soon to know with any certainty more than 72 hours out and the surface levels should be very dry, but we will continue to monitor in case any wintry mischief issues become a possibility later this week.

EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
152 AM EST MON JAN 05 2015

VALID 12Z THU JAN 08 2015 - 12Z MON JAN 12 2015

...OVERVIEW...
EAST OF THE CONTINENTAL DIVIDE---A SERIES OF COLD CANADIAN HIGH
PRESSURE SYSTEMS SPREAD ACROSS THE LOWER 48...WITH BELOW NORMAL
TEMPERATURES EXPECTED FOR THE BETTER PART OF THIS MEDIUM RANGE
PERIOD.

WEST OF THE DIVIDE---A PACIFIC AIRMASS IS INTRODUCED---AND ITS
INFLUENCES DE-AMPLIFYING THE UPPER-LEVEL FLOW BY NEXT WEEK ACROSS
SOUTHWEST CANADA AND THE WEST COAST. PART OF THE DE-AMPLIFICATION
PROCESS---AN ACTIVE SOUTHERN BRANCH OF THE UPPER-LEVEL JET EMERGES
IN NORTHERN MEXICO---ACROSS THE SOUTHERN PLAINS...SOUTHEAST AND
SOUTHERN MID-ATLANTIC STATES.

...UNCERTAINTY ASSESSMENT...
THE MEDIUM RANGE FORECAST CHALLENGE IS TO GRADUALLY TRANSITION THE
FLOW PATTERN ALOFT IN THE WEST AND ACCURATELY DEPICT THE TIMING OF
PACIFIC ENERGY---THAT WILL 'UNDERCUT' THE UPPER RIDGE AXIS FROM
THE SOUTHERN ALASKA PANHANDLE SOUTHWARD TO THE OREGON
CASCADES---AND THEN CARRY THE ENERGY/MOISTURE DOWNSTREAM ACROSS
THE PLAINS. AND DOWNSTREAM...IS DEFINITELY WHERE A MODIFIED-ARCTIC
AIRMASS WILL BE PLACE---DRAPED ACROSS THE EASTERN HALF OF THE
NATION.

FROM A SITUATIONAL AWARENESS STANDPOINT---THE PATTERN SETUP IN THE
WEST AND THE ENVIRONMENT IN PLACE---EAST OF THE DIVIDE---AHEAD OF
THE INTRODUCTION OF THE PACIFIC FLOW---WILL LIKELY BECOME A WINTRY
ONE. THE INTRODUCTION OF A SOUTHERN BRANCH OF THE UPPER-LEVEL
JET---FAVORS THE SOUTHERN PLAINS AND SOUTHEAST...WITH AN
OVER-RUNNING GULF MOISTURE STREAM BEING THE ONE DETAIL THAT WILL
CHANGE WITH TIME.

THE LEE SLOPES OF THE ROCKIES WILL BE ANOTHER REGIONAL
CHALLENGE---AN AREA WHERE THE PACIFIC AIRMASS GRADUALLY
OVERRUNS...AND PERIODICALLY DISPLACES THE ARCTIC AIRMASS.
TEMPERATURES AND LOCAL UPSLOPE PRECIPITATION WILL BE THE PRIMARY
CONCERNS FROM CENTRAL MONTANA TO SOUTHWEST TEXAS.

...MODEL PREFERENCES...
NO PERFECT PROG OUT THERE---BUT THERE IS A GROWING CONFIDENCE IN
THE DIRECTION OF THE FORECAST...GIVEN THE CURRENT ORIENTATION OF
THE UPPER-LEVEL RIDGE AXIS OVER THE GULF OF ALASKA---AND CURRENT
CONDITIONS IN THE PACIFIC NORTHWEST AND ALASKA PANHANDLE. THE
FORECAST HAS LEANED---AND CONTINUES TO LEAN ON THE ECENS/ECMWF
SOLUTION. ANTICIPATE A VERY SLOW EROSION OF THE ARCTIC
AIRMASS---AND NOT TO OCCUR MUCH AT ALL EAST OF THE
MISSISSIPPI/LOWER MISSOURI AND NORTH OF THE OHIO RIVERS DURING
THIS MEDIUM RANGE PERIOD.

...SENSIBLE WEATHER HIGHLIGHTS...
LAKE-EFFECT/UPSLOPE SNOWFALL AND VERY COLD CONDITIONS WILL BE THE
PREVAILING WEATHER CONDITIONS ACROSS THE GREAT LAKES AND
NORTHEAST.

EAST OF 100W LONGITUDE---TEMPERATURES WILL BE BELOW NORMAL AND
EXPECT TWO COLD CANADIAN SURFACE HIGHS TO SETTLE IN ALONG THE
LOWER OHIO VALLEY AND PIEDMONT THIS MEDIUM RANGE
PERIOD---PRODUCING PERIODS OF SUB-FREEZING CONDITIONS FOR THE
ENTIRE GULF COAST...NORTH FLORIDA AND SOUTHEAST TEXAS---AND THE
POTENTIAL FOR WINTER-LIKE PRECIPITATION---NEXT WEEKEND IN THESE
AREAS---AND POINTS NORTHEASTWARD---INCLUDING THE TENNESSEE VALLEY
AND SOUTHERN APPALACHIANS.
VOJTESAK

[srainhoutx]

The 12Z GFS is suggesting a reinforcing shot of cold air arrives Friday and breaks out some sleet and snow across the Dallas/Ft Worth Metroplex into Shreveport as the front continues heading S. The upper air disturbance begins to near W Texas from Northern Mexico Friday afternoon/evening as a Coastal wave develops along the Lower Texas Coast. Frozen precip breaks out across the Hill Country into the Austin area and N and E and even suggesting there may be some potential for an icy mix into the Beaumont/Lake Charles area on Saturday.

[cperk]

srainhoutx that wintry weather on that 6oz GFS looks like it's inching pretty close to SE Texas.

[srainhoutx]

Interestingly the 12Z Euro has joined the GFS solutions (both the old and the new parallel GFS) in suggesting we may have some p-type issues to contend with later this week.

[srainhoutx]

Updated surface charts for day 3 to 7 suggest the Coastal wave/trough idea may be legitimate. The Day 4 to 5 QPF is in agreement with some light precip developing Thursday evening into Saturday with the Day 6 to 7 QPF increasing later on Saturday into early Monday.

[srainhoutx]

Afternoon updated CPC Day 8+ Analogs and Day 6-10 Temperature and Precipitation forecasts.

[ronyan]

Today's runs of the GFS are quite cold for SE TX over the next week, keeping the majority of us below 50F from Wednesday through Jan 13th.

As is common with Arctic fronts, this one may come in a few degrees colder than forecast, which would produce a damaging freeze over the entire region to the coast. As Jeff Linder pointed out in his discussion yesterday, in this type of freeze (advective), the normal means of protecting plants may fail due to the higher winds expected overnight on Wednesday/Thursday. What is the recommended action for protecting plants in an advective freeze? In the past I've put a heat generating lamp near the plants and then put a tarp over the plants.

[MontgomeryCoWx]

Top analog is 1/2/85, eh?

Anyone remember what happened on that date. Hint: The southern part of TX got happy weather!

[srainhoutx]

Top analog is 1/2/85, eh?

Anyone remember what happened on that date. Hint: The southern part of TX got happy weather!

13.5 inches of snow in San Antonio between January 11th and 13th. Folks stranded from Del Rio to College Station. Yep, I remember...

https://www.youtube.com/watch?v=bbM-dr_WfNg

[harpman]

Question: What I'm hearing here in S.E. Louisiana is that the cold air will move out rather quickly by the weekend. Any thoughts or opinions? How long is it forecasted to remain in your area?

[Ptarmigan]

Top analog is 1/2/85, eh?

Anyone remember what happened on that date. Hint: The southern part of TX got happy weather!

Big freeze came in January and February 1985. December 1984 was a warm one. There was a weak La Nina in place. It shws a warm December does not mean a warm winter. December 1989 was cold, but January and February 1990 were warm.

[jasons2k]

Today's runs of the GFS are quite cold for SE TX over the next week, keeping the majority of us below 50F from Wednesday through Jan 13th.

As is common with Arctic fronts, this one may come in a few degrees colder than forecast, which would produce a damaging freeze over the entire region to the coast. As Jeff Linder pointed out in his discussion yesterday, in this type of freeze (advective), the normal means of protecting plants may fail due to the higher winds expected overnight on Wednesday/Thursday. What is the recommended action for protecting plants in an advective freeze? In the past I've put a heat generating lamp near the plants and then put a tarp over the plants.

That's about all you can do - try to keep wind out and hold-in some ground heat. Be careful with tarps or anything synthetic - they can burn and suffocate your plants after the sun comes out. Never use plastic.

Also, keep in mind different plants have different levels of hardiness. This freeze looks like a doozie, so even some marginally tender zone 9 type plants may be in jeopardy.

If you have tender palms, you can wrap the crown and trunk with a freeze cloth. If needed, Christmas lights inside the wrap can give you additional protection. In an extreme case, you can cut off all the fronds and wrap the whole crown and trunk...but I'm probably the only nut in Houston who does anything like that.

Not this year, however. I'm done. I might save the Pygmy date if I have time, but that's it.

[skidog40]

Ice

[skidog40]

snow

[BlueJay]

Not a fan of ice, but it can be beautiful. (trying to be optimistic) Snow might be better.

[tx_kingwood32]

Doubtful will get any snow out of this..*maybe* a ice pellet or two north of Houston around Huntsville

[srainhoutx]

Evening briefing from Jeff:

Significant cold air outbreak heading for the southern plains and TX.

Hard freeze likely Thursday morning over much of the area.

Very cold rain with some sleet possible Friday/Saturday.

Strong arctic high pressure cell over NE Canada will unleash into the US tomorrow and roar off the TX coast early Wednesday. Surface pressure pushes through 1055mb and approach 1060mb over the central plains Wednesday with surface pressure anomalies pushing over 3SD above normal…barometric pressure records may be established over portions of the central and southern plains with this massive arctic high pressure cell. Temperatures in NW Canada are currently in the -40F to -47F range and this air mass will be headed south down the plains very quickly over the next 24-36 hours. Leading edge of the bitter cold air mass will move off the TX coast early Wednesday with already cold temperatures falling during the day. Highs in the 40’s will be reached early with temperatures falling into the 30’s during the day under strong N winds. Wind chill values will fall into the 20’s during the day…making today feel warm. It is going to be cold so prepare accordingly!

Wednesday night/Thursday Morning:

Prolonged hard freeze likely over at least the northern part of the area (N of HWY 105).

Wind Chill Advisories possible over portions of the area.

Strong cold air advection will continue Wednesday night with advection of freezing line deep into the area just after sunset and continued temperature fall all night even with winds staying up. Wind chills will fall into the 10’s and may require wind chill advisory for portions of the area for Thursday morning. Mid and upper level cloud deck streaming overhead from weak upper system near Baja looks to push slightly southward Thursday morning allowing areas north of I-10 to clear some. Given the gravity of the arctic high pressure dome to our north forcing very cold air into the region…think several hours of sub-freezing conditions are likely even with gusty winds and clouds…would go even colder if winds were calm and skies clear and records would likely fall in that event. Extremely dry air mass with dewpoints in the 1’s and 10’s certainly support very cold temperatures, but will moderate over those low values due to continued strong winds and clouds.

Lows Thursday Morning:

N of Hwy 105: 18-22

N of I-10: 25-29

Harris County inside Beltway 8: 27-30

N of HWY 35: 29-32

Beaches: 33-35

Hard freeze criteria is certainly possible north of Hwy 105 with 2 hours or longer below 25. Expect freezing conditions of 8-14 hours across the region. Could even approach hard freeze warning criteria along and north of FM 2920, but still some uncertainty on clouds this far south.

This freeze will likely be particularly damaging as it will be advective in nature (strong winds pushing colder air into the region). 90% of our freezes in this area are radiative or happen on clear calm nights when the temperature cools toward the dewpoints. Radiative freezes allow excellent opportunity for covering of vegetation to produce a “greenhouse effect” as the warmth from the ground is trapped under the protective covering. Advective freezes remove the warmth from the ground with the gusty winds and reduce the effectiveness of a protective covering usually resulting in extensive damage to cold sensitive vegetation and citrus.

Areas north of HWY 105 suggest take all precautions to protect any exposed outdoor pipes as forecasted temperatures of this magnitude for this period of time tend to cause freezing of pipes in this region.

Pets and livestock should be sheltered and water sources checked for ice formation and blockage.

Will continue to refine temperatures for Thursday morning, but all cold weather precautions should be taken for this freeze.

Many areas will not warm above freezing on Thursday until mid to late morning with high temperatures only in the upper 30’s to near 40.

Friday-Saturday:
Baja system ejects toward TX with coastal low forming over the lower TX coast. 1060mb arctic high slides E toward IN and weakens to 1041mb, but still ridges SSW into TX. Cold air looks hard to dislodge and onset of overrunning moisture looks to begin by midday Friday. Friday morning low temperatures look to once again reach freezing across a good part of the area with only a very slow warm up on Friday. Forecast profiles suggest onset of rainfall may be mixed with or all sleet north of a line from Brenham to Conroe to Livingston during the day Friday. Would like to see more warm air advection above the surface to be confident in all rain across those northern counties. Deep surface dry layer will also have to be overcome for precipitation to reach the surface which will likely delay the onset to the warmer parts of midday to afternoon Friday.

Forecast becomes even more uncertain Friday night-Saturday as GFS backs another surge of arctic air into the region with rainfall increasing as overrunning pattern establishes and surface layer moistens. Surface temperatures will fall near or below freezing Friday night north of a line from College Station to Huntsville to Livingston with sleet/rain possible. Am a bit worried that the high temperature forecast for Saturday is only 36-38 for IAH which does not give much room for the models to be “too warm” before we would see possible freezing rain further south. Additionally dewpoints for IAH on the GFS are 28 to 32 on Saturday with a 71% chance of rain which does not really make much sense…would expect a closer dewpoint/temperature for such a forecast rain chance…suggesting either the dewpoints are too low or the surface temperature is too warm.

For now will keep everything liquid south of a College Station to Livingston line both Friday night and Saturday, but this period bears close watch as only a slightly colder surface temperature could result in P-type problems deeper across the area. Forecast soundings show a fairly significant warm advection pattern developing above the surface cold dome Saturday which should reduce any sleet threat and at least attempt to erode the surface cold dome or modify it (warm rain drops falling through the cold air)…this may be what saves the area from a prolonged ice storm in the end.