January 27 - 29, 2014 Winter Storm Discussion

HOUSTON:

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
351 PM CST SAT JAN 25 2014

.DISCUSSION...
WHAT A DIFFERENCE A DAY MAKES. WEST SOUTHWEST WINDS AND PARTLY
CLOUDY SKIES HAVE ALLOWED TEMPERATURES TO WARM TO NEAR 60 DEGREES
THIS AFTERNOON. EXPECT SIMILAR CONDITIONS ON SUNDAY...WITH
TEMPERATURES LIKELY NEARING 70 ACROSS MUCH OF THE REGION.

AFTER OUR BRIEF RESPITE OLD MAN WINTER WILL RETURN ON MONDAY AS A
STRONG FRONT BRINGS ARCTIC AIR BACK TO THE REGION. HIGH
TEMPERATURES WILL LIKELY OCCUR IN THE MORNING AS THE FRONT SHOULD
BE MOVING THROUGH COLLEGE STATION BY DAYBREAK AND INTO THE HOUSTON
METRO AREA BY LUNCHTIME. TEMPERATURES TUESDAY MORNING WILL FALL
BELOW FREEZING ACROSS ALL BUT THE IMMEDIATE COASTLINE WITH
NORTHERN AREAS FALLING INTO THE MID 20S. OF GREATER CONCERN IS THE
APPROACH OF AN UPPER LEVEL SHORTWAVE WHICH WILL LEAD TO THE
POTENTIAL FOR SOME FROZEN PRECIPITATION TUESDAY INTO WEDNESDAY.
MODELS HAVE TRENDED SLIGHTLY SLOWER WITH THE APPROACH OF THIS
FEATURE ALLOWING SURFACE AND NEAR SURFACE TEMPERATURES TO COOL
FURTHER. WHILE THERE REMAINS GREAT UNCERTAINTY WITH THIS EVENT
THERE IS ENOUGH MODEL CONSENSUS TO INTRODUCE A MENTION OF FROZEN
PRECIPITATION INTO THE FORECAST. TEMPERATURES LOOK TO BE COLDER
THAN LAST WEEK WHICH WOULD SHIFT THE THREAT MORE TOWARD SLEET AND
SNOW...RATHER THAN FREEZING RAIN. GREATEST IMPACTS WILL LIKELY BE
CONFINED TO AN AREA ALONG AND SOUTH OF A LINE FROM COLLEGE STATION
TO HOUSTON TO WINNIE. FURTHER NORTH...MOISTURE WILL BE SOMEWHAT
LIMITED AND SNOW FLURRIES ARE POSSIBLE. ONE CONCERN WITH THIS
SOLUTION WILL BE THE AMOUNT OF INTERACTION WITH THE SHORTWAVE AND
THE UPPER LEVEL LOW WHICH IS FORECAST TO HANG BACK OVER NORTHERN
MEXICO...WHICH COULD CHANGE THE AMOUNT OF MOISTURE AVAILABLE TO
WORK WITH. AGAIN...EXPECT TO SEE CHANGES IN THE FORECAST AS WE GET
CLOSER BUT ANOTHER BRUSH WITH WINTER WEATHER LOOKS POSSIBLE THIS
WEEK.

PRECIPITATION WILL EXIT THE REGION BY WEDNESDAY AFTERNOON WITH
ANOTHER QUICK WARMUP EXPECTED MUCH AS WE ARE SEEING NOW. ANOTHER
FRONT WILL ARRIVE NEXT WEEKEND BRINGING RAIN CHANCES FOR MUCH OF
THE REGION BUT TEMPERATURES WILL NOT NEARLY BE AS COLD.


JACKSON:


AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON MS
352 PM CST SAT JAN 25 2014

.SHORT TERM...(TONIGHT THROUGH MONDAY NIGHT)...

LOW LEVEL RETURN FLOW WILL TAKE HOLD OF THE REGION TONIGHT AS THE
SURFACE HIGH OFF TO OUR SOUTH SHIFTS EAST. WINDS WILL BE FAIRLY
LIGHT THROUGH THE FIRST PART TO THE EVENING...AND COUPLED WITH CLEAR
SKIES AND DRY AIR IN PLACE SHOULD SET UP IDEAL RADIATIONAL COOLING
CONDITIONS. NOT LOOKING FOR LOWS TONIGHT TO GET A COLD AS LIGHT
NIGHT THOUGH AS UPPER LEVEL CLOUDS BEGIN MOVING IN AFTER MIDNIGHT.
BEST CHANCE TO GET INTO THE MID 20S WILL BE ACROSS ERN/NERN ZONES IN
LINE WITH 12Z MAV GUIDANCE. DESPITE THE COLD OF LATE TOMORROW
AFTERNOON LOOKS TO BE VERY SEASONAL FOR LATE JAN WITH HIGH
TEMPERATURES CLIMBING INTO THE UPPER 50S/LOWER 60S AREAWIDE.

THINGS WILL BEGIN TO CHANGE LATE SUN NIGHT INTO EARLY MON MORNING
THOUGH AS YET ANOTHER STRONG COLD FRONT SWINGS ACROSS THE REGION. IT
WILL BE NOTICEABLY WINDIER IN WAKE OF THE FRONT...AND IT'S QUITE
POSSIBLE WE'LL NEED A WIND ADVISORY FOR AT LEAST THE DELTA/PERHAPS
AREAWIDE/ THROUGH MOST OF THE DAYLIGHT HOURS. TEMPERATURES LATE
MONDAY NIGHT WILL ONLY FALL INTO THE LOWER 40S/UPPER 30S IN ADVANCE
OF THE FRONT THANKS TO CLOUDS/SOUTHERLY WINDS IN PLACE. ONCE AGAIN
HIGH TEMPERATURES FOR MON ALONG THE HWY 82 CORRIDOR WILL BE TRICKY
AS THE FRONT IS ON OUR DOORSTEP AROUND DAYBREAK. EXPECT A STEADY
DROP IN TEMPS THROUGH THE DAY AS THE FRONT PASSES WITH NORTHERN
ZONES FALLING INTO THE UPPER 20S BY SUNDOWN. WIND CHILLS NORTH OF
I-20 WILL EASILY BE IN THE UPPER TEENS BY MON AFTERNOON AS WELL. THE
WINDS WILL SUBSIDE A BIT HEADED INTO MON NIGHT BUT WE'RE STILL
LOOKING AT SUSTAINED WINDS OF 12-15 MPH THROUGH THE OVERNIGHT
HOURS...LEADING TO BITTERLY COLD WIND CHILLS/ESPECIALLY NORTH OF I-20
WHERE SINGLE DIGITS APPEAR LIKELY. A WIND CHILL ADVISORY WILL ALMOST
CERTAINLY BE NEEDED NORTH OF I-20 FOR MON NIGHT/EARLY TUE MORNING.

AS FOR THE WINTRY PRECIP POTENTIAL IN WAKE OF THE FRONT HEADED INTO
TUE...THE 12Z NAM/09Z SREF WERE STILL BULLISH ON THE SNOW AND EVEN
SOME FREEZING RAIN/SLEET POTENTIAL ALONG THE HWY 84 CORRIDOR...WITH
THE 12Z GFS/ECMWF KEEPING THINGS DRY. THE PREVIOUS DISCUSSION
REGARDING THE UNCERTAINTY REMAINS VALID AND WILL APPEND BELOW. STAY
TUNED. /BK/

.LONG TERM...(TUESDAY THROUGH FRIDAY)...

A STRONG BAROCLINIC ZONE WILL SET UP ACROSS THE GULF COAST STATES AS
THE FRONT CONTINUES TO PUSH SOUTH TUE MORNING. WHILE THE GFS/ECMWF
REMAIN BEARISH WITH PRECIPITATION POTENTIAL IN WAKE OF THE FRONT...A
NUMBER OF MODELS (GEM/GEFS/SREF/NAM) INDICATE JUST ENOUGH BACKING OF
THE MID LEVEL FLOW/ISENTROPIC UPGLIDE WILL HELP TO BREAK OUT
PRECIPITATION ACROSS SOUTHERN ZONES LATE MON NIGHT INTO EARLY TUE.
WITH CONTINUED COLD ADVECTION...THIS PRECIPITATION WOULD LIKELY BE IN
THE FORM OF SNOW...ALTHOUGH THE NAM SHOWS A PRONOUNCED WARM LAYER
ALOFT THAT WOULD INCREASE THE ODDS FOR FREEZING RAIN AND SLEET ALONG
AND SOUTH OF HWY 84. ALL GUIDANCE INDICATE THE COLUMN WOULD BE COLD
ENOUGH FOR ALL SNOW TUESDAY...AND THE GEM AND SEVERAL GEFS/SREF
MEMBERS ACTUALLY INDICATE THE POTENTIAL FOR A FEW INCHES OF SNOW. BUT
GIVEN THAT THE BULK OF GUIDANCE IS ON THE DRY SIDE...WILL KEEP POPS
LOW FOR NOW.

WILL NEED TO CLOSELY WATCH FOR MORE DIGGING OF THE LONGWAVE TROUGH
AND GREATER ENERGY ROUNDING ITS BASE THAT COULD INCREASE LIFT OVER
THE AREA. THE 06Z GFS INDICATES THAT HIGH PRECIPITABLE WATER > 1 INCH
WILL BE NEAR THE GULF COAST AND MASS FIELDS SUGGEST IT ONLY TAKE
SLIGHT PERTURBATIONS TO MAKE A BIG DIFFERENCE IN QPF AS WAS THE CASE
IN THE PAST EVENT OVER LA/SRN MS.

OTHERWISE...MOST FOCUS WILL CONTINUE TO BE ON THE COLD AS WIND CHILL
READINGS COULD FALL INTO THE SINGLE DIGITS ONCE AGAIN ON TUESDAY
NIGHT. IT LOOKS LIKE HARD FREEZE CONDITIONS WILL LIKELY BE MET IN THE
SAME AREA AS TEMPERATURES POTENTIALLY REMAIN BELOW FREEZING FROM
MONDAY NIGHT THROUGH AT LEAST TUESDAY NIGHT...AND PERHAPS EVEN
THROUGH WEDNESDAY NIGHT IN A FEW LOCATIONS ALONG AND NORTH OF THE HWY
82 CORRIDOR. LOWS TUESDAY NIGHT WILL LIKELY REACH THE SINGLE DIGITS
TO TEENS.

MODEL CONSENSUS IS THAT THE ARCTIC AIR WILL PERSIST THROUGH
WEDNESDAY NIGHT...BUT FORECAST CONFIDENCE IS NOT HIGH AS RECENT RUNS
OF THE GFS SUGGEST THE LOW-LEVEL THERMAL TROUGH WILL PULL OUT MUCH
MORE QUICKLY WEDNESDAY LEADING TO NOT SO COLD CONDITIONS WEDNESDAY
NIGHT. HAVING SAID THAT...THE 00Z ECWMF ENSEMBLE MEAN AND GEFS ARE
CONSIDERABLY SLOWER WITH WARM-UP. IN FACT...THE 00Z GFS WAS THE WARM
OUTLIER OF ALL GFS ENSEMBLE MEMBERS. SO HAD TO DO SOME MAJOR
REVISIONS TO MOS GUIDANCE AS A RESULT BOTH TO CUT TEMPERATURES AND
REDUCE POPS SOME GIVEN THE OVERDONE WARM ADVECTION.

THURSDAY AND BEYOND...THERE IS LITTLE DOUBT NOW THAT A MAJOR PATTERN
CHANGE IS TAKING PLACE AND DETERMINISTIC MODELS ARE STRUGGLING WITH
RUN-TO-RUN CONSISTENCY AND DETAILS IN THIS TRANSITION AS WE GO FROM
LATE WEEK INTO THE WEEKEND. MUCH MILDER AND WETTER CONDITIONS ARE
LIKELY AS THE SOUTHEAST CONUS/WRN ATLANTIC RIDGE BUILDS WHILE THE
LONGWAVE TROUGH SHIFTS TO OUR WEST AND ALLOWS FOR STRONG SOUTHWEST
FLOW. IT IS TOO EARLY TO GO INTO MUCH DETAIL ON THIS PORTION OF THE
FORECAST. /EC/

&&