Post by SKYSUMMIT on Feb 22, 2015 16:01:29 GMT -6
HGX Afternoon Discussion:
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
358 PM CST SUN FEB 22 2015
.DISCUSSION...
SCATTERED LIGHT RAIN PASSING ACROSS AND JUST EAST OF THE I-45
CORRIDOR NORTH OF CITY THIS AFTERNOON. THE STATIONARY BOUNDARY
NESTLED IN ACROSS THE SOUTHERN THIRD OF THE FORECAST AREA HAS
CREATED QUITE THE DIFFERENCE IN WEATHER CONDITIONS BETWEEN THE
NORTHERN CWA AND THE SOUTHERN CWA. SOUTH OF THIS BOUNDARY...THAT
ACTUALLY APPEARED TO PULL NORTH AS A WARM FRONT EARLIER THIS
AFTERNOON...SOUTHEAST BREEZES AND PARTIAL SUN AS TEMPERATURES
WARMED INTO THE MIDDLE TO UPPER 70S. NORTH OF THIS BOUNDARY...A
DIFFERENT STORY UNDER LOW OVERCAST...LIGHT DRIZZLE/RAIN...AND
TEMPERATURES THAT STRUGGLED TO ACHIEVE THE LOWER 50S. OVER THE
NEXT 24 TO 36 HOURS...SIGNIFICANT CHANGES WILL OCCUR AS OLD MAN
WINTER RETURNS AND MAKES HIS PRESENCE FELT ACROSS THE REGION.
A SECONDARY REINFORCING COLD ARCTIC AIR MASS IS NOW WORKING ITS
WAY INTO NORTHWEST TEXAS/PANHANDLE...THE SOUTHERN EXTENT OF THIS
AIR MASS (COLD FRONT) NOW PUSHING SOUTHWARD INTO THE HILL COUNTRY.
A TIGHT OFFSHORE PRESSURE GRADIENT FROM A LARGE 1045 MB HIGH DROPPING
INTO THE CENTRAL PLAINS...ALONG WITH A BLAST OF LOW LEVEL SUB FREEZING
AIR REACHING THE CENTRAL FA BY TOMORROW NIGHT...WILL AID IN STRENGTHENING
NORTHERLIES TO NEAR WIND ADVISORY CRITERIA ALONG THE IMMEDIATE COAST
MONDAY MORNING. AS WE ARE WITHIN THAT THIRD PERIOD WINDOW OF 36
HOURS...HAVE ISSUED A FREEZE ADVISORY FOR THE NORTHERN HALF OF
THE CWA THAT WILL BEGIN AT 00Z TUESDAY AND BE IN EFFECT THROUGH
15Z TUESDAY. THIS MORNING'S NPW MODELING HAVE COME IN WITH GOOD
AGREEMENT IN RELATION TO PRIOR RUNS...BOTH IN TIMING OF COLD AIR
AND PRECIPITATION TYPE OF -FZRA/-FZDZ NORTH OF A BRENHAM TO CONROE
TO LIVINGSTON LINE. THE ONE NOTICEABLE DIFFERENCE IS THAT QPF HAS
TAPERED OFF THROUGH TUESDAY MORNING. CONFIDENCE IS FAIRLY HIGH
THAT WET METAL SURFACES OR ELEVATED ROADWAYS WILL DEVELOP A THIN
GLAZE OF ICE SOMETIME DURING THE OVERNIGHT HOURS TUESDAY MORNING.
AN OVERRUNNING TYPE DRIZZLE OR LIGHT RAIN SITUATION DEVELOPING AND
FALLING THROUGH A VERY WARM MID-LAYER AND INTO A SHALLOW 3K FT
SUB-FREEZING LAYER WILL ACCRETE TO NO MORE THAN A TENTH OF AN
INCH OF ICE THROUGH MID TO LATE TUESDAY MORNING...OR WHEN WARMING
INTO THE MIDDLE 30S BEGINS MID-LATE TUE MORNING.
A PROGRESSIVE SHORTWAVE TROUGH ORIGINATING OUT OFF THE LOWER
ROCKY MTN LEES WILL TRAVEL ON THROUGH WEDNESDAY...KEEPING RAIN
CHANCES IN THE MODERATE CATEGORY THROUGH WEDNESDAY AFTERNOON. A
FEW DRY AND CHILLY DAYS IN THE 30S (MORNINGS) AND 40S/50S (AFTERNOONS)
DAYS FROM LATE WEDNESDAY THROUGH EARLY SATURDAY AS TEXAS FALLS IN
A NEAR ZONAL WESTERLY FLOW PATTERN WITH A COOL NORTHEAST BREEZE/
PARTIALLY CLOUDY SKIES. WEEKEND PRECIPITATION CHANCES WILL GRADUALLY
INCREASE THROUGH TIME AS A DEEPENING WESTERN CONUS LOW TRANSLATES
TO PLACING THE SOUTHERN PLAINS INTO A WARM SECTOR PATTERN. AFTER A
COLD...WET AND RAW WEEK...EARLY WEEK CONDITIONS SHOULD APPEAR TO
IMPROVE...AT LEAST FROM A TEMPERATURE STANDPOINT...AS READINGS
SHOULD ONCE AGAIN SPIKE IN THE SLIGHTLY ABOVE NORMAL UPPER 60S TO
MIDDLE 70S (BY SUNDAY OR MONDAY).
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
358 PM CST SUN FEB 22 2015
.DISCUSSION...
SCATTERED LIGHT RAIN PASSING ACROSS AND JUST EAST OF THE I-45
CORRIDOR NORTH OF CITY THIS AFTERNOON. THE STATIONARY BOUNDARY
NESTLED IN ACROSS THE SOUTHERN THIRD OF THE FORECAST AREA HAS
CREATED QUITE THE DIFFERENCE IN WEATHER CONDITIONS BETWEEN THE
NORTHERN CWA AND THE SOUTHERN CWA. SOUTH OF THIS BOUNDARY...THAT
ACTUALLY APPEARED TO PULL NORTH AS A WARM FRONT EARLIER THIS
AFTERNOON...SOUTHEAST BREEZES AND PARTIAL SUN AS TEMPERATURES
WARMED INTO THE MIDDLE TO UPPER 70S. NORTH OF THIS BOUNDARY...A
DIFFERENT STORY UNDER LOW OVERCAST...LIGHT DRIZZLE/RAIN...AND
TEMPERATURES THAT STRUGGLED TO ACHIEVE THE LOWER 50S. OVER THE
NEXT 24 TO 36 HOURS...SIGNIFICANT CHANGES WILL OCCUR AS OLD MAN
WINTER RETURNS AND MAKES HIS PRESENCE FELT ACROSS THE REGION.
A SECONDARY REINFORCING COLD ARCTIC AIR MASS IS NOW WORKING ITS
WAY INTO NORTHWEST TEXAS/PANHANDLE...THE SOUTHERN EXTENT OF THIS
AIR MASS (COLD FRONT) NOW PUSHING SOUTHWARD INTO THE HILL COUNTRY.
A TIGHT OFFSHORE PRESSURE GRADIENT FROM A LARGE 1045 MB HIGH DROPPING
INTO THE CENTRAL PLAINS...ALONG WITH A BLAST OF LOW LEVEL SUB FREEZING
AIR REACHING THE CENTRAL FA BY TOMORROW NIGHT...WILL AID IN STRENGTHENING
NORTHERLIES TO NEAR WIND ADVISORY CRITERIA ALONG THE IMMEDIATE COAST
MONDAY MORNING. AS WE ARE WITHIN THAT THIRD PERIOD WINDOW OF 36
HOURS...HAVE ISSUED A FREEZE ADVISORY FOR THE NORTHERN HALF OF
THE CWA THAT WILL BEGIN AT 00Z TUESDAY AND BE IN EFFECT THROUGH
15Z TUESDAY. THIS MORNING'S NPW MODELING HAVE COME IN WITH GOOD
AGREEMENT IN RELATION TO PRIOR RUNS...BOTH IN TIMING OF COLD AIR
AND PRECIPITATION TYPE OF -FZRA/-FZDZ NORTH OF A BRENHAM TO CONROE
TO LIVINGSTON LINE. THE ONE NOTICEABLE DIFFERENCE IS THAT QPF HAS
TAPERED OFF THROUGH TUESDAY MORNING. CONFIDENCE IS FAIRLY HIGH
THAT WET METAL SURFACES OR ELEVATED ROADWAYS WILL DEVELOP A THIN
GLAZE OF ICE SOMETIME DURING THE OVERNIGHT HOURS TUESDAY MORNING.
AN OVERRUNNING TYPE DRIZZLE OR LIGHT RAIN SITUATION DEVELOPING AND
FALLING THROUGH A VERY WARM MID-LAYER AND INTO A SHALLOW 3K FT
SUB-FREEZING LAYER WILL ACCRETE TO NO MORE THAN A TENTH OF AN
INCH OF ICE THROUGH MID TO LATE TUESDAY MORNING...OR WHEN WARMING
INTO THE MIDDLE 30S BEGINS MID-LATE TUE MORNING.
A PROGRESSIVE SHORTWAVE TROUGH ORIGINATING OUT OFF THE LOWER
ROCKY MTN LEES WILL TRAVEL ON THROUGH WEDNESDAY...KEEPING RAIN
CHANCES IN THE MODERATE CATEGORY THROUGH WEDNESDAY AFTERNOON. A
FEW DRY AND CHILLY DAYS IN THE 30S (MORNINGS) AND 40S/50S (AFTERNOONS)
DAYS FROM LATE WEDNESDAY THROUGH EARLY SATURDAY AS TEXAS FALLS IN
A NEAR ZONAL WESTERLY FLOW PATTERN WITH A COOL NORTHEAST BREEZE/
PARTIALLY CLOUDY SKIES. WEEKEND PRECIPITATION CHANCES WILL GRADUALLY
INCREASE THROUGH TIME AS A DEEPENING WESTERN CONUS LOW TRANSLATES
TO PLACING THE SOUTHERN PLAINS INTO A WARM SECTOR PATTERN. AFTER A
COLD...WET AND RAW WEEK...EARLY WEEK CONDITIONS SHOULD APPEAR TO
IMPROVE...AT LEAST FROM A TEMPERATURE STANDPOINT...AS READINGS
SHOULD ONCE AGAIN SPIKE IN THE SLIGHTLY ABOVE NORMAL UPPER 60S TO
MIDDLE 70S (BY SUNDAY OR MONDAY).
?).
