Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 12/27/14
AREA FORECAST DISCUSSION
NWS TUCSON AZ
340 PM MST THU DEC 25 2014
.SYNOPSIS...EXPECT BREEZY TO WINDY CONDITIONS EARLY THIS EVENING
FOLLOWED BY A GOOD CHANCE OF VALLEY RAIN AND MOUNTAIN SNOW TONIGHT.
THE BEST CHANCE OF PRECIPITATION WILL BE SOUTHEAST OF TUCSON. A FEW
LINGERING SHOWERS WILL OCCUR ACROSS EASTERN SECTIONS FRIDAY...THEN
DRY CONDITIONS WILL PREVAIL THIS WEEKEND AND EARLY NEXT WEEK.
WIDESPREAD FREEZING TEMPERATURES WILL PREVAIL FRIDAY NIGHT...AND A
HARD FREEZE MAY OCCUR ACROSS THE TUCSON METRO AREA.
&&
.DISCUSSION...SHOWERS HAVE YET TO DEVELOP WEST OF TUCSON AT THIS
TIME AS HAS BEEN CONSISTENTLY ADVERTISED VIA VARIOUS NWP MODELS.
HOWEVER...CLOUDS CONTINUE TO THICKEN ACROSS CENTRAL PIMA COUNTY AND
SRN PINAL COUNTY. HAVE NOTED THAT THE LATEST RUC HRRR DEVELOPS LIGHT
PRECIP ECHOES SW OF TUCSON BY 5 PM MST FOLLOWED BY AN EXPANSIVE AREA
OF PRECIP ECHOES...SOME PERHAPS THAT MAY PRODUCE HEAVY RAINFALL...
FROM THE FAR SRN PORTIONS OF THE TUCSON METRO AREA SWWD INTO SOUTH
CENTRAL PIMA COUNTY EARLY THIS EVENING. THE BULK OF THESE ECHOES ARE
THEN PROGGED TO MOVE SEWD MAINLY ACROSS COCHISE/SANTA CRUZ COUNTIES
LATER THIS EVENING.
AT ANY RATE...HAVE CONTINUED WITH A GOOD CHANCE OF VALLEY RAIN/
MOUNTAIN SNOW SHOWERS MOSTLY FROM TUCSON EWD/SWD THIS EVENING. HAVE
ENDED PRECIP FROM TUCSON WWD LATE TONIGHT...BUT HAVE KEPT SCATTERED
TO NUMEROUS SHOWERS ACROSS ERN SECTIONS. A SLIGHT CHANCE OF SHOWERS
WILL CONTINUE ACROSS ERN SECTIONS FRI MORNING...AND A FEW LINGERING
SHOWERS MAY YET CONTINUE NEAR THE NEW MEXICO BORDER FRI AFTERNOON.
STORM TOTAL LIQUID AMOUNTS AND SNOW ACCUMULATIONS REMAIN UNCHANGED.
THUS...LIQUID AMOUNTS WILL GENERALLY RANGE BETWEEN ONE TENTH OF AN
INCH AND ONE THIRD OF AN INCH...WITH SNOW ACCUMULATIONS OF 2-5
INCHES ABOVE 7000 FEET.
DRY CONDITIONS WILL THEN PREVAIL STARTING FRI EVENING AND CONTINUE
THRU TUE. THE FOCUS OF ATTENTION WILL THEN TURN TOWARD THE NEXT
DEEPENING UPPER TROUGH AND CLOSED LOW OVER THE SWRN CONUS BY THE
MIDDLE OF NEXT WEEK. 25/12Z GFS/ECWMF/CMC WERE IN GOOD AGREEMENT
THAT THIS SYSTEM WILL BRING ANOTHER CHANCE OF VALLEY RAIN/MOUNTAIN
SNOW...ESPECIALLY WED NIGHT AND NEW YEARS DAY. HAVE MAINTAINED A
SLIGHT CHANCE OF SHOWERS ACROSS THE HIGHER TERRAIN EAST OF TUCSON
TUE NIGHT. THERE IS A SLIGHT CHANCE OF VALLEY RAIN/MOUNTAIN SNOW
SHOWERS WED...AND POPS WERE INCREASED WED NIGHT INTO THE CHANCE-
CATEGORY ACROSS ERN SECTIONS. A CHANCE OF MOUNTAIN SNOW SHOWERS WILL
CONTINUE EAST OF TUCSON NEXT THUR...WITH A SLIGHT CHANCE OF SHOWERS
AS FAR WEST AS TUCSON. THIS SYSTEM HOLDS THE POTENTIAL TO PRODUCE
SNOW LEVELS AS LOW AS THE VALLEY FLOORS ACROSS COCHISE COUNTY AND
GRAHAM COUNTY.
FINALLY...A FREEZE WARNING WAS ISSUED FOR MUCH OF PIMA COUNTY AND
SRN PINAL COUNTY LATE FRIDAY NIGHT INTO EARLY SAT MORNING. THE
POTENTIAL EXISTS FOR A HARD FREEZE TO OCCUR ACROSS MUCH OF THE
TUCSON METRO AREA...AT LEAST FOR A FEW HOURS. THUS...THIS FREEZE
WARNING WILL POSSIBLY BE MODIFIED FOR A HARD FREEZE WARNING...
PARTICULARLY FOR ERN PIMA COUNTY INCLUDING TUCSON. OTHERWISE...
DAYTIME TEMPS FRI-SAT WILL BE WELL BELOW SEASONAL NORMALS FOLLOWED
BY A WARMING TREND SUN-MON. EXPECT NEAR NORMAL HIGH TEMPS TUE...
THEN MUCH COOLER TEMPS WILL RETURN WED-THUR.
&&
.AVIATION...VALID THRU 26/23Z.
A LOW PRESSURE SYSTEM MOVING ACROSS THE FOUR CORNERS REGION WILL
RESULT IN SCATTERED TO NUMEROUS -SHRA AND HIGHER TERRAIN -SHSN THIS
EVENING AND TONIGHT...MAINLY FROM TUCSON EASTWARD. SCT-BKN CLOUDS AT
4-7K FT AGL. MVFR CONDITIONS WILL OCCUR AT TIMES...ESPECIALLY ACROSS
HIGHER TERRAIN. ISOLATED -SHRA AND HIGHER TERRAIN -SHSN WILL PREVAIL
EAST OF TUCSON FRIDAY MORNING. SURFACE WIND WILL GENERALLY BE
SWLY/WLY AT 15-30 KTS WITH GUSTS TO AROUND 40 KTS THRU 26/02Z.
DIMINISHING SURFACE WIND THIS EVENING AND TONIGHT...WITH SURFACE
WIND LESS THAN 15 KTS BY 26/10Z. AVIATION DISCUSSION NOT UPDATED FOR
TAF AMENDMENTS.
&&
.FIRE WEATHER...A STRONG STORM SYSTEM WILL MOVE THROUGH THE FOUR
CORNERS AREA TONIGHT...AND EAST OF THE REGION ON FRIDAY. BREEZY TO
WINDY CONDITIONS WILL PERSIST INTO THE EARLY EVENING HOURS TONIGHT
BEFORE DIMINISHING. LESS WIND IS EXPECTED OVER THE WEEKEND. THERE
WILL BE A GOOD CHANCE OF VALLEY RAIN AND MOUNTAIN SNOW TONIGHT. A
CONTINUED SLIGHT CHANCE OF SHOWERS WILL OCCUR MAINLY NEAR THE NEW
MEXICO BORDER FRIDAY...FOLLOWED BY DRY CONDITIONS THIS WEEKEND AND
EARLY NEXT WEEK.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 7 PM MST THIS EVENING FOR AZZ503-507-508-
512-513.
FREEZE WARNING FROM MIDNIGHT FRIDAY NIGHT TO 9 AM MST SATURDAY
FOR AZZ501-502-504>506.
&&
$$
VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
DISCUSSION...FRANCIS
AVIATION/FIRE WEATHER...ZELL
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
909 AM MST THU DEC 25 2014
.SYNOPSIS...
A SOMEWHAT DRY LOW PRESSURE SYSTEM WILL SLIDE THROUGH THE AREA TODAY
BEFORE SLOWING AND LINGERING OVER THE FOUR CORNERS THROUGH THE
WEEKEND. THIS SYSTEM WILL BRING COOLER AND BREEZY CONDITIONS ALONG
WITH A CHANCE OF SOME LIGHT SHOWERS...AND POSSIBLY A LIGHT DUSTING OF
SNOW...OVER THE HIGHER TERRAIN OF SOUTH-CENTRAL ARIZONA THIS
AFTERNOON AND EVENING INTO FRIDAY. A DRY AND CONTINUED COOL WEATHER
PATTERN WILL PERSIST FROM THROUGH EARLY NEXT WEEK.
&&
.DISCUSSION...
MID MORNING WATER VAPOR IMAGERY REVEALS LOW PRESSURE OVER UTAH WITH
A SHORTWAVE TROUGH EXTENDING SOUTHWARD THROUGH PORTIONS OF
ARIZONA...SOUTHEAST NEVADA...AND SOUTHEAST CALIFORNIA. A SURFACE
COLD/COOL FRONT IS POSITIONED ROUGHLY FROM FLAGSTAFF TO LAKE HAVASU
AS OF 16Z WITH SOME LIGHT SHOWERS NOTED ON RADAR ACROSS NORTHERN
ARIZONA. ACROSS THE LOWER AZ DESERTS...CONDITIONS REMAIN DRY BUT
CLOUDS ARE INCREASING JUST A BIT AHEAD OF THE FRONT.
IN THE SHORT TERM...THE FRONT WILL MOVE THROUGH THE AREA RELATIVELY
QUICKLY...A BIT FASTER THAN MODELS HAD PREVIOUSLY INDICATED...AND
COULD VERY WELL BE EXITING THE STATE BY EARLY EVENING. LATEST HI-RES
GUIDANCE INCLUDING THE HRRR AND LOCAL WRFS SUGGEST A FEW SHOWERS
DEVELOPING EARLY THIS AFTERNOON IN THE HIGHER TERRAIN LOCATIONS
NORTH/EAST OF PHOENIX...WITH MORE COVERAGE ACROSS PORTIONS OF
SOUTHEAST ARIZONA. ACROSS THE PHOENIX AREA...ANY SHOWERS THAT
DEVELOP WOULD BE WIDELY SCATTERED AT BEST AND WOULD BE VERY SHORT
LIVED. THE INHERITED FORECAST OF 10 POPS ACROSS THE METRO STILL
SEEMS VALID WITH 30-40 POPS CERTAINLY WARRANTED EAST OF PHOENIX. I
TRIMMED THINGS BACK JUST A BIT AFTER 06Z AS THE FRONT SHOULD BE WELL
SOUTH/EAST OF THE AREA BY THEN AND DRIER AIR SHOULD BE MOVING IN
FROM THE NORTH.
IN TERMS OF SNOWFALL...IT WILL BE A RACE BETWEEN HOW QUICKLY THE
COLDER AIR MOVES INTO PLACE VS HOW QUICKLY THE PRECIPITATION EXITS
THE AREA. SNOW LEVELS ARE EXPECTED TO FALL BELOW 5000 FEET THIS
AFTERNOON ALTHOUGH GIVEN THE RAPID NATURE OF THE FRONT...PRECIP
SHOULD BE COMING TO AN END RIGHT AROUND THE SAME TIME. COULD BE A
BRIEF MIX OF RAIN/SNOW WITH LITTLE TO NO ACCUMULATION ABOVE 5000FT
THIS AFTERNOON/EARLY EVENING BUT THAT`S ABOUT IT. NO MAJOR
WINTER-TYPE CONCERNS EXPECTED WITH THIS SYSTEM.
FINALLY...THERE SHOULD BE SOME BREEZINESS COINCIDENT WITH THE
FRONTAL PASSAGE LATER THIS AFTERNOON...GENERALLY IN THE 10-20MPH
RANGE WITH OCCASIONAL HIGHER GUSTS ON THE RIDGES NORTH/EAST OF
PHOENIX. OVERALL THE FORECAST IS IN GOOD SHAPE. LOOK FOR HIGHS TO
REACH THE LOWER 60S THIS AFTERNOON...ABOUT 2-3 DEGREES BELOW NORMAL
FOR LATE DECEMBER. SHOULD BE A CHILLY NIGHT ESPECIALLY IN THE
PROTECTED AREAS OF LA PAZ COUNTY AND THE LOW LYING AREAS NEAR THE
COLORADO RIVER WHERE THE WINDS CALM DOWN AFTER SUNSET. EVEN COLDER
TEMPERATURES ARE EXPECTED FRIDAY/FRIDAY NIGHT.
&&
.PREVIOUS DISCUSSION...
FRIDAY MORNING INTO EARLY NEXT WEEK...
UPPER TROUGHING WILL LINGER OVER THE FOUR CORNERS AS THE JET STREAM
DIPS FURTHER TO OUR SOUTH FRIDAY. CLEAR SKIES AND LIGHTER WINDS WILL
TAKE FULL ADVANTAGE OF THE COOLER AIRMASS BEHIND THE FRONT AND RESULT
IN SOME OF OUR COOLEST MORNINGS SO FAR THIS LATE FALL/WINTER FOR
FRIDAY AM AND THE COMING WEEKEND. DAYTIME TEMPERATURES FRIDAY COULD
BE ANYWHERE FROM 8 TO 10 DEGREES BELOW SEASONAL NORMALS WITH
WIDESPREAD 50S ACROSS THE LOWER DESERTS. FRIDAY NIGHT HAS THE
POTENTIAL TO BRING FREEZING TEMPERATURES TO NORTHERN PINAL
COUNTY...INCLUDING THE FAR SOUTHEAST AND WESTERN FRINGES OF THE
PHOENIX METRO...AS WELL AS RURAL AREAS OF SOUTHWEST ARIZONA. HIGH
TEMPERATURES FOR THE WEEKEND COULD STRUGGLE TO BREAK INTO THE 60S
ACROSS MANY OF THE LOWER DESERT LOCALES WITH OVERNIGHT LOWS DIPPING
INTO THE 30S...AND BRIEFLY THE UPPER 20S...IN SPOTS. IN ANTICIPATION
OF THE UPCOMING COLD MORNINGS...A SPECIAL WEATHER STATEMENT (SPSPSR)
HAS BEEN ISSUED FOR LA PAZ CO. FOR FRIDAY MORNING AND A FREEZE
WARNING HAS BEEN ISSUED FOR SATURDAY MORNING ACROSS LA PAZ...NW
MARICOPA...AND NW PINAL COUNTIES.
TAKING A BROAD BRUSH APPROACH FROM THE WIDELY VARYING MODEL FCST FOR
THE EXTENDED...MOSTLY DRY AND COOL NORTHWEST FLOW WITH EMBEDDED
SHORTWAVES WILL HOLD OVER THE REGION FOR EARLY NEXT WEEK...KEEPING
TEMPERATURES AT OR BELOW SEASONAL NORMALS WHILE PERIODICALLY BRINGING
CLOUDS INTO THE REGION. 00Z OPERATIONAL SOLNS FROM THE GFS/ECMWF/GEM
ALL ADVERTISE A LARGE UPPER LOW DEVELOPING INTO THE SW STATES WITH
CONSIDERABLE MOISTURE FIELDS AND QPF VALUES BY TUESDAY.
MEANWHILE...ONLY A SMALL PERCENTAGE OF ENSEMBLE MEMBERS SUPPORT
THEIR OPERATIONAL COUNTERPARTS. FOR NOW...MAINTAINED A COOL FORECAST
FOR BOTH HIGHS AND LOWS AND BLENDED INTO CLIMO POP INFLUENCE IN THE
EXTENDED FOR TUESDAY AND BEYOND.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
A COLD FRONT WILL PASS THROUGH THE PHOENIX TERMINALS AROUND 18Z
CAUSING A RATHER ABRUPT WIND SHIFT. WHILE A BRIEF HIGHER GUST MAY BE
POSSIBLE...SPEEDS SHOULD LARGELY REMAIN BELOW 15KT. COINCIDENT WITH
FROPA...A RATHER NARROW BAND OF CIGS IN A 5K-8K AGL WILL AFFECT THE
AERODROME SPACE WITH SOME ACCOMPANYING VIRGA. THERE IS MODERATE
CONFIDENCE CIGS WILL ONLY PREVAIL FOR A COUPLE HOURS AND REMAIN
MOSTLY ABOVE 6K FT...BUT SOME PARTIAL MOUNTAIN OBSCURATION MAY BE AN
IMPACT. RAPID CLEARING BY SUNSET WILL YIELD NO AVIATION CONCERNS
OVERNIGHT.
SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA...INCLUDING KIPL AND
KBLH...
A COLD FRONT WILL PASS THROUGH SOUTHEAST CALIFORNIA THIS MORNING
CAUSING A PERIOD OF GUSTY WINDS. THE INITIAL POST FRONTAL PRESSURE
PACKING HAS CAUSED GUSTS OVER 35KT AT KIPL...THOUGH THESE SPEEDS
SHOULD DECREASE RAPIDLY WHILE THE DIRECTION TURN MORE TO THE N/NW
THROUGH THE MORNING. OTHERWISE...PERSISTENT HIGHER GUSTS NEAR 25 KT
WILL PREVAIL INTO THE LATE AFTERNOON. SOME RESIDUAL MOISTURE BEHIND
THE FRONT MAY CAUSE A BRIEF PERIOD OF CIGS IN A 5K-7K AGL...BUT
THESE CIGS SHOULD BE SHORT LIVED. WIND SPEEDS WILL DECREASE BY
SUNSET WITH NO AVIATION IMPACTS OVERNIGHT.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
SATURDAY THROUGH WEDNESDAY...
TRANQUIL DRY AND ABNORMALLY COOL WEATHER WILL PREVAIL OVER THE
WEEKEND INTO EARLY NEXT WEEK WITH NO FIRE WEATHER CONCERNS. ONLY A
BRIEF PERIOD OF SOMEWHAT GUSTY WINDS DOWN THE COLORADO RIVER VALLEY
WILL DISRUPT OTHERWISE NEARLY CALM CONDITIONS. AFTERNOON HUMIDITY
VALUES WILL ONLY FALL INTO A 20 TO 30 PERCENT RANGE WITH GOOD TO
EXCELLENT OVERNIGHT RECOVERY. THE POTENTIAL EXISTS FOR ANOTHER WIND
PRODUCING AND WETTER WEATHER SYSTEM AFFECTING THE DISTRICT BY THE
MIDDLE OF NEXT WEEK.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...FREEZE WARNING FROM MIDNIGHT FRIDAY NIGHT TO 8 AM MST SATURDAY
AZZ021-022-028.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...LEINS/NOLTE
AVIATION...MO
FIRE WEATHER...MO
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
929 AM MST THU DEC 25 2014
.UPDATE...
ISSUED AT 929 AM MST THU DEC 25 2014
HAVE REINITIALIZED THE FORECAST GRIDS WITH THE LATEST
OBSERVATIONS. FRONTAL PUSH HAS BEGUN TO DROP INTO NORTHERN
COLORADO WITH SNOW ALREADY BEING REPORTED IN CHEYENNE. SOME DRYING
IS MOVING IN WITH THE SOUTHWEST FLOW ALOFT WHICH IS CLEARING
SKIES OVER MOST OF THE AREA EXCEPT FAR NORTHERN COLORADO. HOWEVER
WITH THE FRONT PUSHING DOWN AND UPSLOPE FLOW INCREASING...EXPECT
THE NORTHERN FRONT RANGE TO INCREASE IN CLOUD COVER OVER THE
COUPLE HOURS. A SECONDARY PUSH IS STILL SHOWN IN THE MODELS AROUND
5 PM TONIGHT WITH STRONGER WINDS AND BETTER MOISTURE...WHICH WILL
LIKELY BRING THE HEAVIER SNOWFALL. THIS STILL LINES UP WELL WITH
THE CURRENT HIGHLIGHTS...SO WILL NOT ADJUST ANYTHING AT THIS TIME.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT )
ISSUED AT 346 AM MST THU DEC 25 2014
AN UPPER LEVEL LOW WILL CLOSE OFF OVER UTAH TODAY AND THEN MOVE INTO
THE FOUR CORNERS AREA BY LATE TONIGHT. AT THE SFC LOW PRES WILL
INTENSIFY JUST SOUTH OF DENVER THRU THE AFTN AND THEN MOVE SE INTO
SERN CO BY EARLY THIS EVENING. MEANWHILE A SURGE OF COOLER AIR WILL
GRADUALLY MOVE INTO NERN CO THRU THE DAY WITH INCREASING UPSLOPE
FLOW NORTH OF THE BNDRY LATER THIS AFTN INTO THE EVENING HOURS.
MEANWHILE WILL SEE SOME MID LVL ASCENT ACROSS THE AREA LATER THIS
AFTN INTO TONIGHT WITH DIFFLUENT FLOW ALOFT. SNOW WILL INCREASE IN
THE MTNS THIS AFTN AND AT LOWER ELEVATIONS NR THE WY BORDER BY 21Z
WITH ADDITIONAL DEVELOPMENT SPREADING SOUTH ACROSS THE NRN FOOTHILLS
AND IN AREAS FROM FORT COLLINS TOWARDS BOULDER. AM SOMEWHAT
CONCERNED WITH INCREASING ENE FLOW AND POTENTIAL FOR HEAVIER
SNOWFALL IN ZNS 38 AND 39 FOR THIS EVENING ALONG AND WEST OF I-25.
LATEST RAP IS SHOWING INCREASING POTENTIAL FOR 6 TO 8 INCHES OVER A
3 TO 4 HOUR PERIOD FROM 23Z TO 03Z. THUS WILL UPGRADE ADVISORY TO A
WARNING FOR THESE AREAS. FURTHER SOUTH OVER DENVER HEAVIER SNOW MAY
ALSO DEVELOP OVER THE WRN SUBURBS AT SOME POINT WITH SOME POTENTIAL
FOR WARNING CRITERIA LATER THIS EVENING HOWEVER OVERALL CONFIDENCE
IS NOT AS HIGH SO WILL KEEP CURRENT ADVISORY IN PLACE.
OVER THE PLAINS WILL SEE SNOW GRADUALLY DEVELOP THIS EVENING WITH
ADVISORY AMOUNTS POSSIBLE IN SOME AREAS. WINDS WILL NOT BE REAL
STRONG HOWEVER WILL PROBABLY SEE SOME REDUCED VISIBILITIES AT
TIMES. IN THE MTNS AND FOOTHILLS WILL KEEP PREVIOUS HIGHLIGHTS
INTACT ALTHOUGH SRN FOOTHILLS AND PALMER DIVIDE MAY NOT SEE
HEAVIER SNOWFALL UNTIL AFTER 03Z.
FOR LATER TONIGHT AROUND MIDNIGHT SNOW INTENSITIES MAY BEGIN TO
DECREASE HOWEVER WILL LIKELY SEE AREAS OF STEADIER LIGHT SNOW
THROUGH SUNRISE IN MOST AREAS.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 346 AM MST THU DEC 25 2014
ON FRIDAY...THE UPPER TROUGH WILL BE IN THE VICINITY OF THE FOUR
CORNERS AT 12Z...IT WILL GRADUALLY OPEN UP AND SHIFT EASTWARD
THROUGH THE DAY. THE TROUGH AXIS ITSELF IN PROGGED TO SHIFT TO THE
EAST OF COLORADO BY FRIDAY EVENING. WEAK QG ASCENT WILL BE PRESENT
FRIDAY MORNING...THEN DECREASE THROUGH THE REST OF THE DAY.
ADDITIONAL ACCUMULATIONS ON FRIDAY WILL BE LIGHT...MAYBE ANOTHER 1
TO 4 INCHES IN THE HIGH COUNTRY...AND ANOTHER 1 TO 2 INCHES OVER
THE NORTHEAST PLAINS. A DRIER NORTHWEST TO WESTERLY FLOW ALOFT
WILL DEVELOP LATE FRIDAY NIGHT INTO SATURDAY. LINGERING MOISTURE
AROUND FRIDAY NIGHT SO WL KEEP CHC POPS IN THE MOUNTAINS. MAIN
ADJUSTMENT TO THE GRIDS ON FRIDAY AND FRIDAY NIGHT WAS TO SLOW THE
TIMING A BIT. SATURDAY AND SATURDAY NIGHT...A SHORT WAVE RIDGE
WILL BE OVER THE REGION WITH THE FLOW ALOFT INCREASING AHEAD OF
THE NEXT SYSTEM IN THE PACIFIC NORTHWEST. MOISTURE WILL INCREASE
OVER THE MOUNTAINS BY SUNDAY AFTERNOON WITH INCREASING MID AND
UPPER LEVEL QG ASCENT DEVELOPING AS THE TROUGH MOVES INTO SRN
ID/SWRN WY. THE MDLS KEEP THE TROF AXIS TO THE NORTH AND WEST OF
COLORADO SUNDAY NIGHT WITH A 100 KT WEST TO EAST UPPER JET
TRANSLATING SOUTHWARD ACROSS THE STATE. COULD SEE SOME ENHANCED
CSI BANDS DEVELOP AS WE SLIP TO THE NORTHERN SIDE OF THE JET MAX.
WL GO WITH LIKELY POPS IN THE MOUNTAINS...AND AGAIN SOME
HIGHLIGHTS MAY NEED TO BE POSTED AT SOME POINT. AN ARCTIC COLD
FRONT WILL MOVE INTO THE FRONT RANGE SUNDAY NIGHT INTO MONDAY
MORNING. TEMPERATURES ON MONDAY WL ONLY REACH THE UPPER TEENS. WL
GO WITH CHC POPS AS WELL. ALTHOUGH TIMING WL AGAIN BE AN
ISSUE...WL GO WITH THE TREND OF DRIER BUT CONTINUED COLD FOR
TUESDAY AND WEDNESDAY.
&&
.AVIATION...(FOR THE TAFS THROUGH 18Z FRIDAY MORNING)
ISSUED AT 929 AM MST THU DEC 25 2014
STILL LOOKS AT THIS TIME THAT EVEN THOUGH LIGHT SNOW MAY BEGIN MID
AFTERNOON AT KDEN AND KBJC...IT APPEARS BEST CHANCE FOR HEAVIER SNOW
WILL HOLD OFF UNTIL AFTER 5 PM WITH A SECONDARY COLD PUSH. THEN
EXPECT AN INCREASE IN COVERAGE AND INTENSITY THRU THE EARLY
EVENING HOURS AS IT PUSHES DOWN TO KAPA. SNOW INTENSITY WILL
DECREASE BY MIDNIGHT...BUT WILL CONTINUE TO SEE LIGHT SNOW THRU
SUNRISE. RIGHT NOW WILL GO WITH ACCUMULATIONS IN THE 3 TO 5 INCH
RANGE FOR DIA...5 TO 8 INCH RANGE FOR KBJC AND KAPA FROM 5 PM
THRU 5 AM.
AS FOR WINDS...OVERALL CONFIDENCE IS NOT THAT HIGH FOR LATER THIS
MORNING THRU THE AFTN. THE FIRST INITIAL PUSH HAS COME THROUGH THE
AIRPORTS TO SWITCH THEM TO THE NORTHWEST. LATEST HRRR AND RAP
HAVE HAD VERY DIFFERENT SOLUTIONS FOR THE WIND FIELDS AROUND THE
AIRPORT AS THE LOW PUSHES SOUTH. WITH NORTHWEST WINDS SHOWING
UP...IT SEEMS AS THE RAP HAS THE BETTER HANDLE ON THE SITUATION.
WILL SWITCH THE WINDS TO THE NNW THEN WILL HAVE THEM SLOWLY BACK
TO THE NE OR E BEFORE THE SECOND NORTHERLY PUSH IS EXPECTED
AROUND 01Z.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING FROM 3 PM THIS AFTERNOON TO NOON MST FRIDAY
FOR COZ035-036-039.
WINTER WEATHER ADVISORY FROM 2 PM THIS AFTERNOON TO NOON MST
FRIDAY FOR COZ031-033-034.
WINTER STORM WARNING FROM 3 PM THIS AFTERNOON TO 8 AM MST FRIDAY
FOR COZ038.
WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 8 AM MST
FRIDAY FOR COZ042-043.
WINTER WEATHER ADVISORY FROM 5 PM THIS AFTERNOON TO NOON MST
FRIDAY FOR COZ040-045-046.
WINTER STORM WARNING FROM 5 PM THIS AFTERNOON TO NOON MST FRIDAY
FOR COZ041.
&&
$$
UPDATE...KRIEDERMAN
SHORT TERM...RPK
LONG TERM...COOPER
AVIATION...KRIEDERMAN
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
350 AM MST THU DEC 25 2014
.SHORT TERM...(TODAY THROUGH TONIGHT )
ISSUED AT 346 AM MST THU DEC 25 2014
AN UPPER LEVEL LOW WILL CLOSE OFF OVER UTAH TODAY AND THEN MOVE INTO
THE FOUR CORNERS AREA BY LATE TONIGHT. AT THE SFC LOW PRES WILL
INTENSIFY JUST SOUTH OF DENVER THRU THE AFTN AND THEN MOVE SE INTO
SERN CO BY EARLY THIS EVENING. MEANWHILE A SURGE OF COOLER AIR WILL
GRADUALLY MOVE INTO NERN CO THRU THE DAY WITH INCREASING UPSLOPE
FLOW NORTH OF THE BNDRY LATER THIS AFTN INTO THE EVENING HOURS.
MEANWHILE WILL SEE SOME MID LVL ASCENT ACROSS THE AREA LATER THIS
AFTN INTO TONIGHT WITH DIFFLUENT FLOW ALOFT. SNOW WILL INCREASE IN
THE MTNS THIS AFTN AND AT LOWER ELEVATIONS NR THE WY BORDER BY 21Z
WITH ADDITIONAL DEVELOPMENT SPREADING SOUTH ACROSS THE NRN FOOTHILLS
AND IN AREAS FROM FORT COLLINS TOWARDS BOULDER. AM SOMEWHAT
CONCERNED WITH INCREASING ENE FLOW AND POTENTIAL FOR HEAVIER
SNOWFALL IN ZNS 38 AND 39 FOR THIS EVENING ALONG AND WEST OF I-25.
LATEST RAP IS SHOWING INCREASING POTENTIAL FOR 6 TO 8 INCHES OVER A
3 TO 4 HOUR PERIOD FROM 23Z TO 03Z. THUS WILL UPGRADE ADVISORY TO A
WARNING FOR THESE AREAS. FURTHER SOUTH OVER DENVER HEAVIER SNOW MAY
ALSO DEVELOP OVER THE WRN SUBURBS AT SOME POINT WITH SOME POTENTIAL
FOR WARNING CRITERIA LATER THIS EVENING HOWEVER OVERALL CONFIDENCE
IS NOT AS HIGH SO WILL KEEP CURRENT ADVISORY IN PLACE.
OVER THE PLAINS WILL SEE SNOW GRADUALLY DEVELOP THIS EVENING WITH
ADVISORY AMOUNTS POSSIBLE IN SOME AREAS. WINDS WILL NOT BE REAL
STRONG HOWEVER WILL PROBABLY SEE SOME REDUCED VISBILITIES AT TIMES.
IN THE MTNS AND FOOTHILLS WILL KEEP PREVIOUS HIGHLIGHTS INTACT
ALTHOUGH SRN FOOTHILLS AND PALMER DIVIDE MAY NOT SEE HEAVIER
SNOWFALL UNTIL AFTER 03Z.
FOR LATER TONIGHT AROUND MIDNIGHT SNOW INTENSITIES MAY BEGIN TO
DECREASE HOWEVER WILL LIKELY SEE AREAS OF STEADIER LIGHT SNOW
THROUGH SUNRISE IN MOST AREAS.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 346 AM MST THU DEC 25 2014
ON FRIDAY...THE UPPER TROUGH WILL BE IN THE VICINITY OF THE FOUR
CORNERS AT 12Z...IT WILL GRADUALLY OPEN UP AND SHIFT EASTWARD
THROUGH THE DAY. THE TROUGH AXIS ITSELF IN PROGGED TO SHIFT TO THE
EAST OF COLORADO BY FRIDAY EVENING. WEAK QG ASCENT WILL BE PRESENT
FRIDAY MORNING...THEN DECREASE THROUGH THE REST OF THE DAY.
ADDITIONAL ACCUMULATIONS ON FRIDAY WILL BE LIGHT...MAYBE ANOTHER 1
TO 4 INCHES IN THE HIGH COUNTRY...AND ANOTHER 1 TO 2 INCHES OVER
THE NORTHEAST PLAINS. A DRIER NORTHWEST TO WESTERLY FLOW ALOFT
WILL DEVELOP LATE FRIDAY NIGHT INTO SATURDAY. LINGERING MOISTURE
AROUND FRIDAY NIGHT SO WL KEEP CHC POPS IN THE MOUNTAINS. MAIN
ADJUSTMENT TO THE GRIDS ON FRIDAY AND FRIDAY NIGHT WAS TO SLOW THE
TIMING A BIT. SATURDAY AND SATURDAY NIGHT...A SHORT WAVE RIDGE
WILL BE OVER THE REGION WITH THE FLOW ALOFT INCREASING AHEAD OF
THE NEXT SYSTEM IN THE PACIFIC NORTHWEST. MOISTURE WILL INCREASE
OVER THE MOUNTAINS BY SUNDAY AFTERNOON WITH INCREASING MID AND
UPPER LEVEL QG ASCENT DEVELOPING AS THE TROUGH MOVES INTO SRN
ID/SWRN WY. THE MDLS KEEP THE TROF AXIS TO THE NORTH AND WEST OF
COLORADO SUNDAY NIGHT WITH A 100 KT WEST TO EAST UPPER JET
TRANSLATING SOUTHWARD ACROSS THE STATE. COULD SEE SOME ENHANCED
CSI BANDS DEVELOP AS WE SLIP TO THE NORTHERN SIDE OF THE JET MAX.
WL GO WITH LIKELY POPS IN THE MOUNTAINS...AND AGAIN SOME
HIGHLIGHTS MAY NEED TO BE POSTED AT SOME POINT. AN ARCTIC COLD
FRONT WILL MOVE INTO THE FRONT RANGE SUNDAY NIGHT INTO MONDAY
MORNING. TEMPERATURES ON MONDAY WL ONLY REACH THE UPPER TEENS. WL
GO WITH CHC POPS AS WELL. ALTHOUGH TIMING WL AGAIN BE AN
ISSUE...WL GO WITH THE TREND OF DRIER BUT CONTINUED COLD FOR
TUESDAY AND WEDNESDAY.
&&
.AVIATION...(FOR THE TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 346 AM MST THU DEC 25 2014
AT THIS TIME IT APPEARS BEST CHC OF SNOW AT DIA WILL HOLD OFF UNTIL
AFTER 5 PM WITH AN INCREASE IN COVERAGE AND INTENSITY THRU THE EARLY
EVENING HOURS. SNOW INTENSITY WILL DECREASE BY MIDNIGHT HOWEVER
WILL CONTINUE TO SEE LIGHT SNOW THRU SUNRISE. RIGHT NOW WILL GO
WITH ACCUMULATIONS IN THE 3 TO 5 INCH RANGE FOR DIA FM 5 PM THRU 5
AM.
AS FOR WINDS OVERALL CONFIDENCE NOT THAT HIGH FOR LATER THIS MORNING
THRU THE AFTN. LATEST HRRR AND RAP HAVE BEEN SHOWN A SFC LOW
DEVELOPING JUST TO THE SOUTH OF THE AIRPORT BY MID TO LATE MORNING
WHICH SHIFTS SLOWLY SOUTH THRU THE AFTN. AS A RESULT SSW WINDS THIS
MORNING MAY BECOME MORE ELY BY 18Z AND STAY THAT WAY THRU LATE AFTN.
AFTER 00Z WINDS MAY WILL BECOME MORE NELY AND THEN MORE NLY AROUND
MIDNIGHT.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING FROM 3 PM THIS AFTERNOON TO NOON MST FRIDAY
FOR COZ035-036-039.
WINTER WEATHER ADVISORY FROM 2 PM THIS AFTERNOON TO NOON MST
FRIDAY FOR COZ031-033-034.
WINTER STORM WARNING FROM 3 PM THIS AFTERNOON TO 8 AM MST FRIDAY
FOR COZ038.
WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 8 AM MST
FRIDAY FOR COZ042-043.
WINTER WEATHER ADVISORY FROM 5 PM THIS AFTERNOON TO NOON MST
FRIDAY FOR COZ040-045-046.
WINTER STORM WARNING FROM 5 PM THIS AFTERNOON TO NOON MST FRIDAY
FOR COZ041.
&&
$$
SHORT TERM...RPK
LONG TERM...COOPER
AVIATION...RPK
AREA FORECAST DISCUSSION
NWS NEW YORK NY
116 PM EST THU DEC 25 2014
.SYNOPSIS...
HIGH PRESSURE BUILDS OVER THE SOUTHEASTERN U.S. THROUGH SATURDAY. A
COLD FRONT CROSSES THE TRI-STATE ON SUNDAY. THIS FRONT STALLS OUT
WELL TO THE SOUTH OF LONG ISLAND...AS COLD CANADIAN HIGH PRESSURE
BUILDS IN FROM THE WEST.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
WELL...PANCAKE STRATO-CU HAS FILLED A LOT MORE THAN EXPECTED. THE
SUN WAS NICE WHILE IT LASTED. NARRE-TL HAD NO CLUE ON THESE CLOUDS
AS SEEN IN RAP AND HRRR SOUNDINGS UNDER ESTIMATING SATURATION AT
THE BASE OF THE INVERSION. EXPECT THE CLOUDS TO MIX OUT WITH LOSS
OF SURFACE HEATING STARTING IN THE NEXT 1-2 HOURS AS LAYER IS
THIN.
TEMPERATURES SLOWLY FALL OFF FROM HERE INTO LATE AFTERNOON.
WINDS GUSTS TO 30-40 MPH CONTINUE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
GUSTY WINDS LAST INTO EARLY THIS EVENING...THEN FAIRLY RAPIDLY
DIMINISH THROUGH THE REMAINDER OF THE EVENING.
DEEP LAYERED RIDGING BEGINS TO BUILD IN TONIGHT...WITH ITS AXIS
BUILDING OVER THE AREA ON SATURDAY...THEN SLIDING OFF TO THE EAST
SATURDAY NIGHT. ASSOCIATED SUBSIDENCE UNDER THE RIDGE SHOULD KEEP
THINGS DRY FROM THURSDAY NIGHT-SATURDAY NIGHT...WITH MINIMAL CLOUD
COVER THROUGH SATURDAY...THEN INCREASING MID-HIGH CLOUDS AHEAD OF
A COLD FRONT SATURDAY NIGHT.
FOR LOWS TONIGHT...USED A BLEND OF ECS/MAV/MET GUIDANCE WITH NAM
2-METER TEMPERATURES...WITH VALUES FORECAST TO BE AROUND 10
DEGREES ABOVE NORMAL. A BLEND OF MAV/MET/ECS GUIDANCE WITH NAM
2-METER TEMPERATURES AND A MIX DOWN FROM 975-950 HPA PER BUFKIT
SOUNDINGS WAS USED FOR HIGHS ON FRIDAY...WITH READINGS EXPECTED TO
BE 5-10 DEGREES ABOVE NORMAL.
FOR LOWS FRIDAY NIGHT A BLEND OF MAV/MET GUIDANCE WAS USED...WITH
VALUES AROUND 10-15 DEGREES ABOVE NORMAL. FOR HIGHS SATURDAY A
BLEND OF MAV/MET GUIDANCE WITH NAM 2-METER TEMPERATURES AND A MIX
DOWN FROM 975 HPA PER BUFKIT SOUNDINGS WAS USED. HIGHS SHOULD BE
AROUND 10 DEGREES ABOVE NORMAL. A BLEND OF MEX/MEN/EKD/ECM/ECE/WPC
GUIDANCE WITH NAM 2-METER TEMPERATURES WAS USED FOR LOWS SATURDAY
NIGHT...WITH VALUES FORECAST TO BE 10-15 DEGREES ABOVE NORMAL.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
WITH EXCEPTION OF 24/12Z CMC GPDS - MODELS REMAIN FAIRLY GOOD
AGREEMENT WITH THE IDEA THAT THE COLD FRONT THAT PASSES THROUGH
THE AREA SUNDAY...ENDS UP STALLING OUT TO FAR TO THE SOUTH. LOW
PRESSURE PASSING ALONG THE FRONT HAVE LITTLE, IF ANY, IMPACT ON
THE AREA. TWO POSSIBLE EXCEPTIONS ARE WITH THE INITIAL WAVE OF LOW
PRESSURE AND SECONDARY COLD FRONTAL PASSAGE SUNDAY NIGHT...AND
ANOTHER WAVE OF LOW PRESSURE ON TUESDAY.
FOR NOW...HAVE SLIGHT CHANCE TO CHANCE POPS WITH THE COLD FRONTAL
PASSAGE...THEN SLIGHT CHANCE POPS ACROSS SOUTHERN ZONES WITH THE
PASSAGE OF THE FIRST WAVE. FOR NOW IT APPEARS THE BOUNDARY LAYER
SHOULD BE WARM ENOUGH TO SUPPORT ONLY RAIN IN THIS TIME FRAME.
THE REGION REMAINS IN BETWEEN A CLOSED UPPER LOW TO THE N AND
RIDGING OFF THE FL COAST THROUGH AT LEAST TUESDAY NIGHT...WITH THE
TIMING AND PLACEMENT OF SHORTWAVE TROUGHS EMBEDDED IN THE FLOW
BETWEEN THE TWO DETERMINING THE EXACT TRACK/STRENGTH OF WAVES OF
LOW PRESSURE ALONG THE STALLED COLD FRONT. FOR NOW APPEARS
STRONGEST SHORTWAVE WILL PASS ON TUESDAY...SO HAVE SLIGHT CHANCE
POPS ACROSS SOUTHERN AREAS MONDAY NIGHT/TUESDAY...OTHERWISE HAVE
GONE DRY OVER LAND MONDAY- TUESDAY NIGHT. LIKELY WILL BE COLD
ENOUGH IN THE LOWEST LAYERS TO SUPPORT MAINLY SNOW...EXCEPT FOR
MAYBE AT THE IMMEDIATE COAST. FOR NOW THOUGH ANY PRECIPITATION IS
EXPECTED TO BE LIGHT...AS THE AREA SHOULD BE IN THE NORTHERN
PERIPHERY OF THE SYSTEM.
WEDNESDAY SHOULD BE DRY WITH NORTHERN STREAM RIDGING PASSING OVER
THE AREA.
FOR TEMPERATURES SUNDAY-WEDNESDAY A BLEND OF
MEX/MEN/EKD/ECE/ECM/WPC GUIDANCE WAS USED. AFTER ABOVE NORMAL
TEMPERATURES ON SUNDAY...BELOW NORMAL TEMPERATURES ARE FORECAST
MONDAY-WEDNESDAY.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
HIGH PRESSURE BUILDS IN TODAY WITH VFR AND A STRONG SURFACE WESTERLY
FLOW GUSTING UP TO 35 KT AT NYC METRO UNTIL ABOUT 21Z. BKN-45-050
CIGS SHOULD SCATTER BY ABOUT 21Z AS WELL. WINDS AND GUSTS SHOULD
THEN GRADUALLY DIMINISH AFTER SUNSET.
...NY METRO ENHANCED AVIATION WEATHER SUPPORT...
DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS CAN
BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)
KJFK FCSTER COMMENTS: HIGH CONFIDENCE WIND FCST.
KLGA FCSTER COMMENTS: HIGH CONFIDENCE WIND FCST.
KEWR FCSTER COMMENTS: HIGH CONFIDENCE WIND FCST.
KTEB FCSTER COMMENTS: HIGH CONFIDENCE WIND FCST.
KHPN FCSTER COMMENTS: HIGH CONFIDENCE WIND FCST.
KISP FCSTER COMMENTS: MAY SEE AN OCCASIONAL WIND GUST HIGHER
THAN FCST THIS AFTERNOON.
.OUTLOOK FOR 18Z FRIDAY THROUGH MONDAY...
.FRI-SAT...VFR.
.SUNDAY...MVFR WITH CHANCE OF LIGHT RAIN.
.MON...VFR.
.TUE...LOW CONFIDENCE VFR.
&&
.MARINE...
GALE WARNING...WINDS NOW GUSTING TO GALE FORCE ON LAND IN THE NYC
AREA AND THIS WILL MOVE OUT OVER ALL WATERS BY NOON.
THIS EVENING...WINDS LOWER TO SCA LEVEL QUICKLY THIS EVENING...TAPERING
OFF TO BELOW SCA LEVELS AFTER MIDNIGHT TONIGHT.
SUB-SCA CONDITIONS ARE ANTICIPATED ON FRIDAY INTO NEXT WEEK.
&&
.HYDROLOGY...
DRY THROUGH SATURDAY NIGHT WITH NO SIGNIFICANT PRECIPITATION EXPECTED
FROM SUNDAY-WEDNESDAY AT THIS TIME.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...GALE WARNING UNTIL 6 PM EST THIS EVENING FOR ANZ330-335-338-
340-345-350-353-355.
&&
$$
SYNOPSIS...MALOIT
NEAR TERM...TONGUE
SHORT TERM...MALOIT
LONG TERM...MALOIT
AVIATION...GOODMAN
MARINE...BC/TONGUE
HYDROLOGY...MALOIT
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
902 PM CST FRI DEC 26 2014
.SHORT TERM...
238 PM CST
THROUGH SUNDAY...
AN UPPER LEVEL RIDGE AXIS STRETCHES FROM CUBA UP THE ATLANTIC COAST
WITH THE SURFACE HIGH OVER THE SOUTHEAST U.S. THE UPPER LEVEL RIDGE
SHIFTS VERY LITTLE THROUGH SATURDAY. A NARROW SURFACE TROUGH EXTENDS
FROM TEXAS THROUGH THE UPPER PENINSULA OF MICHIGAN THIS AFTERNOON. A
CLOSED LOW WILL FORM OVER THE MID MISSISSIPPI VALLEY TONIGHT AND
MOVE OVER NORTHERN IL LATE TONIGHT/EARLY SATURDAY MORNING BEFORE
MAKING IT TO QUEBEC SATURDAY EVENING. WEAK HIGH PRESSURE THEN
SPREADS OVER THE CWA SUNDAY.
TEMPERATURES CONTINUE TO CLIMB INTO THE UPPER 40S TO LOWER 50S THIS
AFTERNOON WITH THE MAJORITY OF THE CWA RECEIVING AMPLE SUNSHINE.
CLOUD COVER WILL INCREASE THIS EVENING AND OVERNIGHT AS THE LOW
TAKES SHAPE AND MOVES IN. WITH THE SURFACE LOW PASSING RIGHT
OVERHEAD...THINKING FOG OR DRIZZLE IS PROBABLE ESPECIALLY WEST OF A
MCHENRY TO JOLIET LINE. ONLY HAVE PATCHY FOG IN THE FORECAST...BUT
COULD SEE VSBYS IN SOME AREAS DROP TO AROUND OR LESS THAN ONE MILE
DUE TO FOG OR DRIZZLE.
RAIN/DRIZZLE MOVES IN FROM SOUTHWEST TO NORTHEAST LATE THIS
EVENING...AND LATEST RAP AND HRRR GUIDANCE INDICATE THE PRECIP WILL
MOVE IN QUICKER THAN PREVIOUSLY THOUGHT. IT LOOKS LIKE A GOOD HIGH
POP/LOW QPF SITUATION. HAVE AN INCREASING POP TREND FROM MIDNIGHT
THROUGH THE EARLY MORNING HOURS AS THE LOW MOVES OVERHEAD. LIGHT
RAIN SHIFTS EAST SATURDAY AFTERNOON AS THE LOW CONTINUES NORTHEAST.
GUSTY WEST WINDS ARE EXPECTED TOMORROW WITH GUSTS AROUND 30 MPH IN
THE AFTERNOON. TEMPERATURES WILL ALSO BE FALLING FROM THE LATE
MORNING HOURS ON BEHIND THE LOWS COLD FRONT. HOWEVER AREAS ALONG AND
EAST OF I-55 WILL SEE HIGH TEMPS IN THE MID 40S TO AROUND 50. TEMPS
FALL INTO THE 20S SATURDAY NIGHT.
LIGHT WINDS SHIFT TO OUT OF THE NORTHWEST OR NORTH SUNDAY WITH DRY
CONDITIONS EXPECTED. THE COOLER AIRMASS WILL KEEP HIGH TEMPS IN THE
30S...BUT WE SHOULD SEE SOME SUNSHINE.
JEE
&&
.LONG TERM...
238 PM CST
SUNDAY NIGHT THROUGH FRIDAY...
AN UPPER LEVEL LOW WILL SHIFT EAST OVER NORTHERN QUEBEC
SUNDAY...AND A VORTICITY STREAMER ASSOCIATED WITH THE LOW PUSHES
SOUTH THROUGH THE REGION MONDAY. ANOTHER TROUGH AXIS SWINGS THROUGH
WEDNESDAY. AT THE SURFACE...WEAK HIGH PRESSURE REMAINS OVER THE
REGION SUNDAY NIGHT. A COLD FRONT COINCIDED WITH THE VORT STREAMER
PUSHES THROUGH THE REGION MONDAY. ARCTIC HIGH PRESSURE FOLLOWS THE
COLD FRONT...AND FINALLY SHIFTS SOUTH TO THE GULF STATES THURSDAY.
CLOUDS INCREASE SUNDAY NIGHT AHEAD OF THE COLD FRONT WITH LOW TEMPS
IN THE 20S. FLURRIES AND LIGHT SNOW ARE EXPECTED ALONG THE COLD
FRONT AS MODELS CONTINUE TO FEATURE A LITTLE QPF. COLD AIR MASSES
SUCH AS THIS ONE CAN USUALLY SQUEEZE OUT ANY MOISTURE LINGERING IN
THE AIR SO HAVE HIGHER POPS WHERE MODELS FEATURED QPF AND FLURRIES
ACROSS THE REST OF THE CWA. NOT EXPECTING MUCH SNOW ACCUMULATION IF
ANY AT ALL. NORTH WINDS DOWN THE LAKE MAY RESULT IN LAKE EFFECT
SNOW OVER NW INDIANA MONDAY NIGHT INTO TUESDAY. COULD SEE A COUPLE
TENTHS OF AN INCH OF SNOW.
THE BIGGER IMPACT WILL BE TEMPERATURES. HIGH TEMPS WILL BE IN THE
LOWER 30S MONDAY THEN ONLY IN THE UPPER TEENS TO MID 20S TUESDAY.
LOW TEMPS TUESDAY WILL BE VARY FROM THE SINGLE DIGITS OVER NORTH
CENTRAL IL TO AROUND 10 DEGREES OVER NORTHWEST INDIANA. BRISK NW
WINDS WILL CREATE BELOW ZERO WINDCHILLS TUESDAY NIGHT INTO WEDNESDAY
MORNING. THE WHOLE CWA FEELS THE CHILL WEDNESDAY WITH HIGH TEMPS
AROUND 20 DEGREES BUT GUSTY WEST WINDS WILL MAKE IT FEEL LIKE IT IS
IN THE SINGLE DIGITS.
THE CENTER OF THE HIGH SHIFTS SOUTH OF THE REGION THURSDAY ALLOWING
TEMPS TO WARM SLIGHTLY INTO THE UPPER 20S THURSDAY. LONG RANGE
GUIDANCE THEN FEATURES A LOW PRESSURE SYSTEM MOVING UP THE OHIO
RIVER VALLEY LATE NEXT WEEK. GUIDANCE HAS THE SYSTEM BRINGING US
SNOW OVER THE WEEKEND...SO WILL KEEP AN EYE ON THIS SYSTEM.
JEE
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 03Z...
* MVFR CIGS GIVE WAY TO VFR FOR A FEW HOURS LATE THIS EVENING.
MVFR RETURNS THEN LOWERS TO IFR OVERNIGHT. LIFR POSSIBLE EARLY
SATURDAY MORNING. IMPROVEMENT TO MVFR TOWARD MIDDAY SATURDAY.
* CHANCE OF LIGHT RAIN/DRIZZLE OVERNIGHT INTO SATURDAY MORNING.
* SOUTH TO SOUTHWEST WINDS BECOME WESTERLY LATE SATURDAY MORNING
AND BECOME GUSTY INTO THE AFTERNOON. A FEW GUSTS NEAR 30 KT POSSIBLE.
MDB
//DISCUSSION...UPDATED 0130Z...
LATEST CIG TRENDS SHOW THAT UPSTREAM CLOUD COVER IS BASED AROUND
040 WITH LOWER CIGS MUCH FURTHER SOUTHWEST. HAVE TWEAKED THE TAFS
TO SHOW CURRENT MVFR IMPROVING TO VFR FOR A FEW HOURS LATE THIS
EVENING BEFORE RETURNING TO MVFR EARLY TONIGHT. TIMING MAY NEED TO
BE TWEAKED BUT HAVE GOOD CONFIDENCE IN THIS TREND.
FROM 00Z...
A TROUGH OF LOW PRESSURE REMAINS TO THE NORTH AND WEST OF THE
TERMINALS THIS EVENING WHILE A LOW PRESSURE CIRCULATION BEGINS TO
TAKE SHAPE OVER THE SOUTHERN PLAINS. WIND SPEEDS HAVE QUICKLY
DROPPED OFF OVER THE LAST HOUR OR SO WITH MOST SITES IN THE 4-6
KT RANGE. WITH CLOUD COVER INCREASING AND THE PRESSURE GRADIENT
SOMEWHAT BAGGY THROUGH THE EVENING SPEEDS WILL LIKELY REMAIN UNDER
8 KT IF NOT UNDER 6 KT FOR THE NEXT FEW HOURS. SPEEDS SHOULD
INCREASE MODESTLY OVERNIGHT AS THE DEVELOPING LOW MOVES NORTHEAST
ACROSS EASTERN IOWA.
MVFR CIGS AROUND 025 CONTINUE TO EXPAND IN COVERAGE ACROSS THE
AREA. LARGE GAPS REMAIN HOWEVER SO INTERMITTENT SCT-BKN COVERAGE
IS LIKELY OVER THE NEXT FEW HOURS BEFORE BECOMING MORE OVC. CIG
BASES WILL ALSO LOWER LATER THIS EVENING THROUGH THE OVERNIGHT
WITH IFR DEVELOPING. TIMING OF THE LOWERING MAY NEED TO BE
ADJUSTED AS IT COULD BE A LITTLE QUICK. LIFR CIGS ARE
POSSIBLE...ESPECIALLY AT RFD TOWARD MORNING AS THE LOW PASSES
NEARBY. WINDS WILL SHIFT WESTERLY AS THE LOW AND ATTENDANT COLD
FRONT PASS DURING THE LATE MORNING. THIS WILL BRING SOME LOW LEVEL
DRYING SO CIGS SHOULD IMPROVE TO MVFR. WINDS WILL PICK UP AND
BECOME GUSTY WITH SOME 30 KT GUSTS POSSIBLE INTO THE AFTERNOON.
SPEEDS WILL EASE UP SATURDAY EVENING. CIGS WILL REMAIN MVFR
THROUGH THE AFTERNOON AND MAY PERSIST THROUGH SATURDAY EVENING AS
WELL.
MDB
//ORD AND MDW CONFIDENCE...UPDATED 03Z...
* HIGH CONFIDENCE IN CIG TRENDS. MEDIUM CONFIDENCE IN TIMING
CHANGE TO AND FROM IFR. LOW CONFIDENCE IN LIFR POTENTIAL.
* MEDIUM-HIGH CONFIDENCE THAT AT LEAST SOME LIGHT RAIN/DRIZZLE
OCCURS. MEDIUM-HIGH CONFIDENCE IN TIMING.
* HIGH CONFIDENCE IN WIND TRENDS. MEDIUM CONFIDENCE IN SPEED
DETAILS.
MDB
//OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z...
SUNDAY...VFR. LIGHT W WINDS BECOMING NNE LATE.
MONDAY...SCHC -SHSN. MVFR PSBL. N TO NE WINDS.
TUESDAY...VFR. BREEZY NW WINDS.
WEDNESDAY AND THURSDAY...VFR. BREEZY SW WINDS AT TIMES.
MDB
&&
.MARINE...
324 PM CST
A TROUGH OF LOW PRESSURE MOVING ACROSS THE REGION IS HELPING TO
PROVIDE SIGNIFICANT DIFFERENCES WITH WIND SPEED AND DIRECTION
ACROSS THE ENTIRE LAKE THIS AFTERNOON...AND EXPECT THESE
DIFFERENCES TO REMAIN IN PLACE TONIGHT INTO SATURDAY MORNING.
WHILE SOUTHERLY FLOW REMAINS IN PLACE OVER THE SOUTHERN HALF OF
THE LAKE...SOUTHERLY WINDS OVER THE NORTHERN HALF ARE ALREADY
SLOWLY BECOMING MORE NORTHERLY AS THIS TROUGH MOVES ACROSS THE
LAKE. THIS TREND WILL CONTINUE OVER THE NORTHERN HALF TONIGHT WITH
MORE NORTHERLY WINDS EXPECTED LATER TONIGHT...WHILE SOUTHERLY
WINDS PERSIST OVER THE SOUTHERN HALF. NEW LOW PRESSURE WILL THEN
DEVELOP ALONG THIS TROUGH/BOUNDARY EARLY SATURDAY MORNING AND MOVE
ACROSS THE LAKE SATURDAY. EXPECT SPEEDS TO INCREASE DURING THE DAY
AS WINDS BECOME MORE WESTERLY IN THE AFTERNOON...AND THEN
NORTHWEST IN THE EVENING. EXPECT SPEEDS TO THEN DIMINISH SATURDAY
NIGHT INTO SUNDAY AS THIS LOW DEPARTS AND HIGH PRESSURE BUILDS
ACROSS THE REGION.
RODRIGUEZ
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ744-LMZ745...10 AM SATURDAY TO 4 AM
SUNDAY.
SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743...10 AM
SATURDAY TO 10 PM SATURDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
725 PM CST FRI DEC 26 2014
.SHORT TERM...
238 PM CST
THROUGH SUNDAY...
AN UPPER LEVEL RIDGE AXIS STRETCHES FROM CUBA UP THE ATLANTIC COAST
WITH THE SURFACE HIGH OVER THE SOUTHEAST U.S. THE UPPER LEVEL RIDGE
SHIFTS VERY LITTLE THROUGH SATURDAY. A NARROW SURFACE TROUGH EXTENDS
FROM TEXAS THROUGH THE UPPER PENINSULA OF MICHIGAN THIS AFTERNOON. A
CLOSED LOW WILL FORM OVER THE MID MISSISSIPPI VALLEY TONIGHT AND
MOVE OVER NORTHERN IL LATE TONIGHT/EARLY SATURDAY MORNING BEFORE
MAKING IT TO QUEBEC SATURDAY EVENING. WEAK HIGH PRESSURE THEN
SPREADS OVER THE CWA SUNDAY.
TEMPERATURES CONTINUE TO CLIMB INTO THE UPPER 40S TO LOWER 50S THIS
AFTERNOON WITH THE MAJORITY OF THE CWA RECEIVING AMPLE SUNSHINE.
CLOUD COVER WILL INCREASE THIS EVENING AND OVERNIGHT AS THE LOW
TAKES SHAPE AND MOVES IN. WITH THE SURFACE LOW PASSING RIGHT
OVERHEAD...THINKING FOG OR DRIZZLE IS PROBABLE ESPECIALLY WEST OF A
MCHENRY TO JOLIET LINE. ONLY HAVE PATCHY FOG IN THE FORECAST...BUT
COULD SEE VSBYS IN SOME AREAS DROP TO AROUND OR LESS THAN ONE MILE
DUE TO FOG OR DRIZZLE.
RAIN/DRIZZLE MOVES IN FROM SOUTHWEST TO NORTHEAST LATE THIS
EVENING...AND LATEST RAP AND HRRR GUIDANCE INDICATE THE PRECIP WILL
MOVE IN QUICKER THAN PREVIOUSLY THOUGHT. IT LOOKS LIKE A GOOD HIGH
POP/LOW QPF SITUATION. HAVE AN INCREASING POP TREND FROM MIDNIGHT
THROUGH THE EARLY MORNING HOURS AS THE LOW MOVES OVERHEAD. LIGHT
RAIN SHIFTS EAST SATURDAY AFTERNOON AS THE LOW CONTINUES NORTHEAST.
GUSTY WEST WINDS ARE EXPECTED TOMORROW WITH GUSTS AROUND 30 MPH IN
THE AFTERNOON. TEMPERATURES WILL ALSO BE FALLING FROM THE LATE
MORNING HOURS ON BEHIND THE LOWS COLD FRONT. HOWEVER AREAS ALONG AND
EAST OF I-55 WILL SEE HIGH TEMPS IN THE MID 40S TO AROUND 50. TEMPS
FALL INTO THE 20S SATURDAY NIGHT.
LIGHT WINDS SHIFT TO OUT OF THE NORTHWEST OR NORTH SUNDAY WITH DRY
CONDITIONS EXPECTED. THE COOLER AIRMASS WILL KEEP HIGH TEMPS IN THE
30S...BUT WE SHOULD SEE SOME SUNSHINE.
JEE
&&
.LONG TERM...
238 PM CST
SUNDAY NIGHT THROUGH FRIDAY...
AN UPPER LEVEL LOW WILL SHIFT EAST OVER NORTHERN QUEBEC
SUNDAY...AND A VORTICITY STREAMER ASSOCIATED WITH THE LOW PUSHES
SOUTH THROUGH THE REGION MONDAY. ANOTHER TROUGH AXIS SWINGS THROUGH
WEDNESDAY. AT THE SURFACE...WEAK HIGH PRESSURE REMAINS OVER THE
REGION SUNDAY NIGHT. A COLD FRONT COINCIDED WITH THE VORT STREAMER
PUSHES THROUGH THE REGION MONDAY. ARCTIC HIGH PRESSURE FOLLOWS THE
COLD FRONT...AND FINALLY SHIFTS SOUTH TO THE GULF STATES THURSDAY.
CLOUDS INCREASE SUNDAY NIGHT AHEAD OF THE COLD FRONT WITH LOW TEMPS
IN THE 20S. FLURRIES AND LIGHT SNOW ARE EXPECTED ALONG THE COLD
FRONT AS MODELS CONTINUE TO FEATURE A LITTLE QPF. COLD AIR MASSES
SUCH AS THIS ONE CAN USUALLY SQUEEZE OUT ANY MOISTURE LINGERING IN
THE AIR SO HAVE HIGHER POPS WHERE MODELS FEATURED QPF AND FLURRIES
ACROSS THE REST OF THE CWA. NOT EXPECTING MUCH SNOW ACCUMULATION IF
ANY AT ALL. NORTH WINDS DOWN THE LAKE MAY RESULT IN LAKE EFFECT
SNOW OVER NW INDIANA MONDAY NIGHT INTO TUESDAY. COULD SEE A COUPLE
TENTHS OF AN INCH OF SNOW.
THE BIGGER IMPACT WILL BE TEMPERATURES. HIGH TEMPS WILL BE IN THE
LOWER 30S MONDAY THEN ONLY IN THE UPPER TEENS TO MID 20S TUESDAY.
LOW TEMPS TUESDAY WILL BE VARY FROM THE SINGLE DIGITS OVER NORTH
CENTRAL IL TO AROUND 10 DEGREES OVER NORTHWEST INDIANA. BRISK NW
WINDS WILL CREATE BELOW ZERO WINDCHILLS TUESDAY NIGHT INTO WEDNESDAY
MORNING. THE WHOLE CWA FEELS THE CHILL WEDNESDAY WITH HIGH TEMPS
AROUND 20 DEGREES BUT GUSTY WEST WINDS WILL MAKE IT FEEL LIKE IT IS
IN THE SINGLE DIGITS.
THE CENTER OF THE HIGH SHIFTS SOUTH OF THE REGION THURSDAY ALLOWING
TEMPS TO WARM SLIGHTLY INTO THE UPPER 20S THURSDAY. LONG RANGE
GUIDANCE THEN FEATURES A LOW PRESSURE SYSTEM MOVING UP THE OHIO
RIVER VALLEY LATE NEXT WEEK. GUIDANCE HAS THE SYSTEM BRINGING US
SNOW OVER THE WEEKEND...SO WILL KEEP AN EYE ON THIS SYSTEM.
JEE
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 130Z...
* MVFR CIGS GIVE WAY TO VFR FOR A FEW HOURS LATE THIS EVENING.
MVFR RETURNS THEN LOWERS TO IFR OVERNIGHT. LIFR POSSIBLE EARLY
SATURDAY MORNING. IMPROVEMENT TO MVFR TOWARD MIDDAY SATURDAY.
* CHANCE OF LIGHT RAIN/DRIZZLE OVERNIGHT INTO SATURDAY MORNING.
* SOUTH TO SOUTHWEST WINDS BECOME WESTERLY LATE SATURDAY MORNING
AND BECOME GUSTY INTO THE AFTERNOON. A FEW GUSTS NEAR 30 KT POSSIBLE.
MDB
//DISCUSSION...UPDATED 0130Z...
LATEST CIG TRENDS SHOW THAT UPSTREAM CLOUD COVER IS BASED AROUND
040 WITH LOWER CIGS MUCH FURTHER SOUTHWEST. HAVE TWEAKED THE TAFS
TO SHOW CURRENT MVFR IMPROVING TO VFR FOR A FEW HOURS LATE THIS
EVENING BEFORE RETURNING TO MVFR EARLY TONIGHT. TIMING MAY NEED TO
BE TWEAKED BUT HAVE GOOD CONFIDENCE IN THIS TREND.
FROM 00Z...
A TROUGH OF LOW PRESSURE REMAINS TO THE NORTH AND WEST OF THE
TERMINALS THIS EVENING WHILE A LOW PRESSURE CIRCULATION BEGINS TO
TAKE SHAPE OVER THE SOUTHERN PLAINS. WIND SPEEDS HAVE QUICKLY
DROPPED OFF OVER THE LAST HOUR OR SO WITH MOST SITES IN THE 4-6
KT RANGE. WITH CLOUD COVER INCREASING AND THE PRESSURE GRADIENT
SOMEWHAT BAGGY THROUGH THE EVENING SPEEDS WILL LIKELY REMAIN UNDER
8 KT IF NOT UNDER 6 KT FOR THE NEXT FEW HOURS. SPEEDS SHOULD
INCREASE MODESTLY OVERNIGHT AS THE DEVELOPING LOW MOVES NORTHEAST
ACROSS EASTERN IOWA.
MVFR CIGS AROUND 025 CONTINUE TO EXPAND IN COVERAGE ACROSS THE
AREA. LARGE GAPS REMAIN HOWEVER SO INTERMITTENT SCT-BKN COVERAGE
IS LIKELY OVER THE NEXT FEW HOURS BEFORE BECOMING MORE OVC. CIG
BASES WILL ALSO LOWER LATER THIS EVENING THROUGH THE OVERNIGHT
WITH IFR DEVELOPING. TIMING OF THE LOWERING MAY NEED TO BE
ADJUSTED AS IT COULD BE A LITTLE QUICK. LIFR CIGS ARE
POSSIBLE...ESPECIALLY AT RFD TOWARD MORNING AS THE LOW PASSES
NEARBY. WINDS WILL SHIFT WESTERLY AS THE LOW AND ATTENDANT COLD
FRONT PASS DURING THE LATE MORNING. THIS WILL BRING SOME LOW LEVEL
DRYING SO CIGS SHOULD IMPROVE TO MVFR. WINDS WILL PICK UP AND
BECOME GUSTY WITH SOME 30 KT GUSTS POSSIBLE INTO THE AFTERNOON.
SPEEDS WILL EASE UP SATURDAY EVENING. CIGS WILL REMAIN MVFR
THROUGH THE AFTERNOON AND MAY PERSIST THROUGH SATURDAY EVENING AS
WELL.
MDB
//ORD AND MDW CONFIDENCE...UPDATED 0130Z...
* HIGH CONFIDENCE IN CIG TRENDS. MEDIUM CONFIDENCE IN TIMING
CHANGE TO AND FROM IFR. LOW CONFIDENCE IN LIFR POTENTIAL.
* MEDIUM-HIGH CONFIDENCE THAT AT LEAST SOME LIGHT RAIN/DRIZZLE
OCCURS. MEDIUM-HIGH CONFIDENCE IN TIMING.
* HIGH CONFIDENCE IN WIND TRENDS. MEDIUM CONFIDENCE IN SPEED
DETAILS.
MDB
//OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z...
SUNDAY...VFR. LIGHT W WINDS BECOMING NNE LATE.
MONDAY...SCHC -SHSN. MVFR PSBL. N TO NE WINDS.
TUESDAY...VFR. BREEZY NW WINDS.
WEDNESDAY AND THURSDAY...VFR. BREEZY SW WINDS AT TIMES.
MDB
&&
.MARINE...
324 PM CST
A TROUGH OF LOW PRESSURE MOVING ACROSS THE REGION IS HELPING TO
PROVIDE SIGNIFICANT DIFFERENCES WITH WIND SPEED AND DIRECTION
ACROSS THE ENTIRE LAKE THIS AFTERNOON...AND EXPECT THESE
DIFFERENCES TO REMAIN IN PLACE TONIGHT INTO SATURDAY MORNING.
WHILE SOUTHERLY FLOW REMAINS IN PLACE OVER THE SOUTHERN HALF OF
THE LAKE...SOUTHERLY WINDS OVER THE NORTHERN HALF ARE ALREADY
SLOWLY BECOMING MORE NORTHERLY AS THIS TROUGH MOVES ACROSS THE
LAKE. THIS TREND WILL CONTINUE OVER THE NORTHERN HALF TONIGHT WITH
MORE NORTHERLY WINDS EXPECTED LATER TONIGHT...WHILE SOUTHERLY
WINDS PERSIST OVER THE SOUTHERN HALF. NEW LOW PRESSURE WILL THEN
DEVELOP ALONG THIS TROUGH/BOUNDARY EARLY SATURDAY MORNING AND MOVE
ACROSS THE LAKE SATURDAY. EXPECT SPEEDS TO INCREASE DURING THE DAY
AS WINDS BECOME MORE WESTERLY IN THE AFTERNOON...AND THEN
NORTHWEST IN THE EVENING. EXPECT SPEEDS TO THEN DIMINISH SATURDAY
NIGHT INTO SUNDAY AS THIS LOW DEPARTS AND HIGH PRESSURE BUILDS
ACROSS THE REGION.
RODRIGUEZ
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ744-LMZ745...10 AM SATURDAY TO 4 AM
SUNDAY.
SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743...10 AM
SATURDAY TO 10 PM SATURDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
600 PM CST FRI DEC 26 2014
.SHORT TERM...
238 PM CST
THROUGH SUNDAY...
AN UPPER LEVEL RIDGE AXIS STRETCHES FROM CUBA UP THE ATLANTIC COAST
WITH THE SURFACE HIGH OVER THE SOUTHEAST U.S. THE UPPER LEVEL RIDGE
SHIFTS VERY LITTLE THROUGH SATURDAY. A NARROW SURFACE TROUGH EXTENDS
FROM TEXAS THROUGH THE UPPER PENINSULA OF MICHIGAN THIS AFTERNOON. A
CLOSED LOW WILL FORM OVER THE MID MISSISSIPPI VALLEY TONIGHT AND
MOVE OVER NORTHERN IL LATE TONIGHT/EARLY SATURDAY MORNING BEFORE
MAKING IT TO QUEBEC SATURDAY EVENING. WEAK HIGH PRESSURE THEN
SPREADS OVER THE CWA SUNDAY.
TEMPERATURES CONTINUE TO CLIMB INTO THE UPPER 40S TO LOWER 50S THIS
AFTERNOON WITH THE MAJORITY OF THE CWA RECEIVING AMPLE SUNSHINE.
CLOUD COVER WILL INCREASE THIS EVENING AND OVERNIGHT AS THE LOW
TAKES SHAPE AND MOVES IN. WITH THE SURFACE LOW PASSING RIGHT
OVERHEAD...THINKING FOG OR DRIZZLE IS PROBABLE ESPECIALLY WEST OF A
MCHENRY TO JOLIET LINE. ONLY HAVE PATCHY FOG IN THE FORECAST...BUT
COULD SEE VSBYS IN SOME AREAS DROP TO AROUND OR LESS THAN ONE MILE
DUE TO FOG OR DRIZZLE.
RAIN/DRIZZLE MOVES IN FROM SOUTHWEST TO NORTHEAST LATE THIS
EVENING...AND LATEST RAP AND HRRR GUIDANCE INDICATE THE PRECIP WILL
MOVE IN QUICKER THAN PREVIOUSLY THOUGHT. IT LOOKS LIKE A GOOD HIGH
POP/LOW QPF SITUATION. HAVE AN INCREASING POP TREND FROM MIDNIGHT
THROUGH THE EARLY MORNING HOURS AS THE LOW MOVES OVERHEAD. LIGHT
RAIN SHIFTS EAST SATURDAY AFTERNOON AS THE LOW CONTINUES NORTHEAST.
GUSTY WEST WINDS ARE EXPECTED TOMORROW WITH GUSTS AROUND 30 MPH IN
THE AFTERNOON. TEMPERATURES WILL ALSO BE FALLING FROM THE LATE
MORNING HOURS ON BEHIND THE LOWS COLD FRONT. HOWEVER AREAS ALONG AND
EAST OF I-55 WILL SEE HIGH TEMPS IN THE MID 40S TO AROUND 50. TEMPS
FALL INTO THE 20S SATURDAY NIGHT.
LIGHT WINDS SHIFT TO OUT OF THE NORTHWEST OR NORTH SUNDAY WITH DRY
CONDITIONS EXPECTED. THE COOLER AIRMASS WILL KEEP HIGH TEMPS IN THE
30S...BUT WE SHOULD SEE SOME SUNSHINE.
JEE
&&
.LONG TERM...
238 PM CST
SUNDAY NIGHT THROUGH FRIDAY...
AN UPPER LEVEL LOW WILL SHIFT EAST OVER NORTHERN QUEBEC
SUNDAY...AND A VORTICITY STREAMER ASSOCIATED WITH THE LOW PUSHES
SOUTH THROUGH THE REGION MONDAY. ANOTHER TROUGH AXIS SWINGS THROUGH
WEDNESDAY. AT THE SURFACE...WEAK HIGH PRESSURE REMAINS OVER THE
REGION SUNDAY NIGHT. A COLD FRONT COINCIDED WITH THE VORT STREAMER
PUSHES THROUGH THE REGION MONDAY. ARCTIC HIGH PRESSURE FOLLOWS THE
COLD FRONT...AND FINALLY SHIFTS SOUTH TO THE GULF STATES THURSDAY.
CLOUDS INCREASE SUNDAY NIGHT AHEAD OF THE COLD FRONT WITH LOW TEMPS
IN THE 20S. FLURRIES AND LIGHT SNOW ARE EXPECTED ALONG THE COLD
FRONT AS MODELS CONTINUE TO FEATURE A LITTLE QPF. COLD AIR MASSES
SUCH AS THIS ONE CAN USUALLY SQUEEZE OUT ANY MOISTURE LINGERING IN
THE AIR SO HAVE HIGHER POPS WHERE MODELS FEATURED QPF AND FLURRIES
ACROSS THE REST OF THE CWA. NOT EXPECTING MUCH SNOW ACCUMULATION IF
ANY AT ALL. NORTH WINDS DOWN THE LAKE MAY RESULT IN LAKE EFFECT
SNOW OVER NW INDIANA MONDAY NIGHT INTO TUESDAY. COULD SEE A COUPLE
TENTHS OF AN INCH OF SNOW.
THE BIGGER IMPACT WILL BE TEMPERATURES. HIGH TEMPS WILL BE IN THE
LOWER 30S MONDAY THEN ONLY IN THE UPPER TEENS TO MID 20S TUESDAY.
LOW TEMPS TUESDAY WILL BE VARY FROM THE SINGLE DIGITS OVER NORTH
CENTRAL IL TO AROUND 10 DEGREES OVER NORTHWEST INDIANA. BRISK NW
WINDS WILL CREATE BELOW ZERO WINDCHILLS TUESDAY NIGHT INTO WEDNESDAY
MORNING. THE WHOLE CWA FEELS THE CHILL WEDNESDAY WITH HIGH TEMPS
AROUND 20 DEGREES BUT GUSTY WEST WINDS WILL MAKE IT FEEL LIKE IT IS
IN THE SINGLE DIGITS.
THE CENTER OF THE HIGH SHIFTS SOUTH OF THE REGION THURSDAY ALLOWING
TEMPS TO WARM SLIGHTLY INTO THE UPPER 20S THURSDAY. LONG RANGE
GUIDANCE THEN FEATURES A LOW PRESSURE SYSTEM MOVING UP THE OHIO
RIVER VALLEY LATE NEXT WEEK. GUIDANCE HAS THE SYSTEM BRINGING US
SNOW OVER THE WEEKEND...SO WILL KEEP AN EYE ON THIS SYSTEM.
JEE
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 00Z...
* MVFR CIGS EXPANDING IN COVERAGE THROUGH THE EVENING THEN
LOWERING TO IFR OVERNIGHT. LIFR POSSIBLE EARLY SATURDAY MORNING.
IMPROVEMENT TO MVFR TOWARD MIDDAY SATURDAY.
* CHANCE OF LIGHT RAIN/DRIZZLE OVERNIGHT INTO SATURDAY MORNING.
* SOUTH TO SOUTHWEST WINDS BECOME WESTERLY LATE SATURDAY MORNING
AND BECOME GUSTY INTO THE AFTERNOON. A FEW GUSTS NEAR 30 KT POSSIBLE.
MDB
//DISCUSSION...UPDATED 00Z...
A TROUGH OF LOW PRESSURE REMAINS TO THE NORTH AND WEST OF THE
TERMINALS THIS EVENING WHILE A LOW PRESSURE CIRCULATION BEGINS TO
TAKE SHAPE OVER THE SOUTHERN PLAINS. WIND SPEEDS HAVE QUICKLY
DROPPED OFF OVER THE LAST HOUR OR SO WITH MOST SITES IN THE 4-6
KT RANGE. WITH CLOUD COVER INCREASING AND THE PRESSURE GRADIENT
SOMEWHAT BAGGY THROUGH THE EVENING SPEEDS WILL LIKELY REMAIN UNDER
8 KT IF NOT UNDER 6 KT FOR THE NEXT FEW HOURS. SPEEDS SHOULD
INCREASE MODESTLY OVERNIGHT AS THE DEVELOPING LOW MOVES NORTHEAST
ACROSS EASTERN IOWA.
MVFR CIGS AROUND 025 CONTINUE TO EXPAND IN COVERAGE ACROSS THE
AREA. LARGE GAPS REMAIN HOWEVER SO INTERMITTENT SCT-BKN COVERAGE
IS LIKELY OVER THE NEXT FEW HOURS BEFORE BECOMING MORE OVC. CIG
BASES WILL ALSO LOWER LATER THIS EVENING THROUGH THE OVERNIGHT
WITH IFR DEVELOPING. TIMING OF THE LOWERING MAY NEED TO BE
ADJUSTED AS IT COULD BE A LITTLE QUICK. LIFR CIGS ARE
POSSIBLE...ESPECIALLY AT RFD TOWARD MORNING AS THE LOW PASSES
NEARBY. WINDS WILL SHIFT WESTERLY AS THE LOW AND ATTENDANT COLD
FRONT PASS DURING THE LATE MORNING. THIS WILL BRING SOME LOW LEVEL
DRYING SO CIGS SHOULD IMPROVE TO MVFR. WINDS WILL PICK UP AND
BECOME GUSTY WITH SOME 30 KT GUSTS POSSIBLE INTO THE AFTERNOON.
SPEEDS WILL EASE UP SATURDAY EVENING. CIGS WILL REMAIN MVFR
THROUGH THE AFTERNOON AND MAY PERSIST THROUGH SATURDAY EVENING AS
WELL.
MDB
//ORD AND MDW CONFIDENCE...UPDATED 00Z...
* HIGH CONFIDENCE IN CIG TRENDS. MEDIUM CONFIDENCE IN TIMING
CHANGE TO AND FROM IFR. LOW CONFIDENCE IN LIFR POTENTIAL.
* MEDIUM-HIGH CONFIDENCE THAT AT LEAST SOME LIGHT RAIN/DRIZZLE
OCCURS. MEDIUM-HIGH CONFIDENCE IN TIMING.
* HIGH CONFIDENCE IN WIND TRENDS. MEDIUM CONFIDENCE IN SPEED
DETAILS.
MDB
//OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z...
SUNDAY...VFR. LIGHT W WINDS BECOMING NNE LATE.
MONDAY...SCHC -SHSN. MVFR PSBL. N TO NE WINDS.
TUESDAY...VFR. BREEZY NW WINDS.
WEDNESDAY AND THURSDAY...VFR. BREEZY SW WINDS AT TIMES.
MDB
&&
.MARINE...
324 PM CST
A TROUGH OF LOW PRESSURE MOVING ACROSS THE REGION IS HELPING TO
PROVIDE SIGNIFICANT DIFFERENCES WITH WIND SPEED AND DIRECTION
ACROSS THE ENTIRE LAKE THIS AFTERNOON...AND EXPECT THESE
DIFFERENCES TO REMAIN IN PLACE TONIGHT INTO SATURDAY MORNING.
WHILE SOUTHERLY FLOW REMAINS IN PLACE OVER THE SOUTHERN HALF OF
THE LAKE...SOUTHERLY WINDS OVER THE NORTHERN HALF ARE ALREADY
SLOWLY BECOMING MORE NORTHERLY AS THIS TROUGH MOVES ACROSS THE
LAKE. THIS TREND WILL CONTINUE OVER THE NORTHERN HALF TONIGHT WITH
MORE NORTHERLY WINDS EXPECTED LATER TONIGHT...WHILE SOUTHERLY
WINDS PERSIST OVER THE SOUTHERN HALF. NEW LOW PRESSURE WILL THEN
DEVELOP ALONG THIS TROUGH/BOUNDARY EARLY SATURDAY MORNING AND MOVE
ACROSS THE LAKE SATURDAY. EXPECT SPEEDS TO INCREASE DURING THE DAY
AS WINDS BECOME MORE WESTERLY IN THE AFTERNOON...AND THEN
NORTHWEST IN THE EVENING. EXPECT SPEEDS TO THEN DIMINISH SATURDAY
NIGHT INTO SUNDAY AS THIS LOW DEPARTS AND HIGH PRESSURE BUILDS
ACROSS THE REGION.
RODRIGUEZ
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ744-LMZ745...10 AM SATURDAY TO 4 AM
SUNDAY.
SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743...10 AM
SATURDAY TO 10 PM SATURDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1145 AM CST THU DEC 25 2014
.UPDATE...
ISSUED AT 704 AM CST THU DEC 25 2014
LITTLE CHANGE WAS MADE TO THE FORECAST AT THIS POINT. SOME
ADJUSTMENT TO CLOUD COVER DUE TO STRATUS TAILING BACK ACROSS THE
NORTHEAST.
&&
.SHORT TERM /TODAY/...
ISSUED AT 356 AM CST THU DEC 25 2014
SATELLITE IS SHOWING THE STRATUS STEADILY PUSHING TO THE EAST AND
OUT OF CENTRAL IOWA. DES MOINES HAD SCATTERED OUT AROUND 3AM AND
THE CLEARING LINE AS OF THAT TIME RAN FROM ESTHERVILLE TO JUST EAST
OF DES MOINES TO JUST EAST OF CENTERVILLE. BY 12Z THE SOUTH SHOULD
BE CLEARING FROM THE STRATUS. THE NORTH IS A LITTLE MORE
PROBLEMATIC AND I BELIEVE LOCATIONS NORTH OF HIGHWAY 20 WILL SEE
STRATUS FOR A FAIR PART OF THE MORNING.
WHILE THE STRATUS WILL LIKELY BE GONE BY THE AFTERNOON...PRETTY
STRONG WARM ADVECTION IS UNDERWAY AND WILL CONTINUE THROUGH TODAY.
MID AND HIGH CLOUDS CURRENTLY OVER NEBRASKA AND THE DAKOTAS WILL
MOVE INTO IOWA AND WHILE THERE SHOULD BE A FAIR AMOUNT OF SUN AND
PLENTY OF BREAKS IN THE CLOUDS IT WILL NOT BE A BRIGHT SUNNY
DAY...AT LEAST FOR THE MOST PART. SOUNDINGS HANG ON TO LOW LEVEL
MOISTURE AND DO INCREASE MID LEVEL MOISTURE BY THE AFTERNOON WHICH
IS EXPECTED AS THE WARM ADVECTION INCREASES. THE NAM IS MORE
BULLISH WHILE THE GFS DOES NOT HOLD ON TO THE MOISTURE AS MUCH. HI-
RES SHORT TERM MODELS LIKE THE RAP AND THE HRRR ALSO INDICATED LESS
CLOUD COVER TODAY...ESPECIALLY SOUTH.
SFC WINDS WILL BECOME WIDESPREAD 10 TO 20 MPH WITH GUSTS TO 25 OR 30
MPH AT TIMES. TEMPS TODAY WILL BE QUITE NICE WITH HIGHS IN THE MID
30S NORTH TO THE MID 40S SOUTH. ENJOY TODAYS TEMPS BECAUSE MODEL
SOUNDINGS CRASH TEMPS BEGINNING TOMORROW.
.LONG TERM /TONIGHT THROUGH TUESDAY/...
ISSUED AT 356 AM CST THU DEC 25 2014
COLD FRONT WILL SETTLE SLOWLY SOUTHEAST INTO IOWA TONIGHT BUT BULK
OF FORCING WILL HAVE MOVED NORTHEAST OF THE STATE WITH INITIAL
WARM ADVECTION SURGE AND ASSOCIATED SHORTWAVE. LOW CLOUDS WILL
DROP INTO THE FAR NORTHWEST OVERNIGHT BEHIND THE BOUNDARY BENEATH
THE SHALLOW FRONTAL INVERSION. THE FRONT IS EXPECTED TO SLOW ON
FRIDAY AS MAIN SHORTWAVE BEGINS TO EJECT FROM THE INTER-MOUNTAIN
WEST. LOW CLOUDS WILL CONTINUE TO GRADUALLY EXPAND SOUTHEAST
ACROSS THE FORECAST AREA ON LOW LEVEL NORTHWEST WINDS. NAM MOST
AGGRESSIVE WITH DEEPER LOW LEVEL SATURATION WHILE GFS/EURO NOT AS
MOIST. NOT REAL CONFIDENT ABOUT THE POSSIBILITY OF FREEZING
DRIZZLE/DRIZZLE GIVEN THE MODEL DISCREPANCIES BUT HAVE INCLUDED
SOME PATCHY AREAS STARTING LATE MORNING IN THE NORTHWEST PER NAM
GIVEN THE DEEPER SATURATION. THIS SPREAD SLOWLY SOUTHEAST INTO THE
AFTERNOON...HOWEVER THE PRECIPITATION WILL BE VERY LIGHT UNTIL THE
MAIN SYSTEM ARRIVES ON FRIDAY NIGHT.
PRECIPITATION WILL BE ON THE INCREASE FRIDAY NIGHT AS THE MAIN
SHORTWAVE APPROACHES. MID LEVEL QG FORCING INTENSIFIES RAPIDLY
FRIDAY EVENING ACROSS THE WEST AND PROPAGATES PRIMARILY ACROSS THE
WEST AND NORTH OVERNIGHT. THIS AREA WILL SEE THE BEST COVERAGE OF
SNOW OVERNIGHT WITH 1 TO 3 INCHES LIKELY ACROSS THE NORTH...MAINLY
ALONG AND NORTH OF HIGHWAY 20 WITH HIGHEST AMOUNTS ALONG THE
MINNESOTA BORDER. FARTHER SOUTH...ANOTHER PRECIPITATION AREA IS
EXPECTED NEAR THE SURFACE FRONT IN THE FAR SOUTHEAST FORECAST AREA
NEAR OTTUMWA WITH LIGHT RAIN INITIALLY CHANGING TO SNOW LATE.
AMOUNTS WILL REMAIN QUITE LIGHT WITH ONLY A DUSTING OF SNOW.
TEMPERATURES WILL COOL WITH A SURGE OF CANADIAN AIR BEHIND THIS
SYSTEM. HOWEVER...THE BIGGER PUSH OF COLD AIR WILL ARRIVE SUNDAY
NIGHT INTO MONDAY AS A COLD FRONT SLIDES THROUGH THE STATE. THERE
WILL BE SOME THREAT OF VERY LIGHT SNOW ON THE BACKSIDE OF THE
BOUNDARY ON MONDAY...HOWEVER THE PUSH OF COLDER AIR WILL BE THE
BIGGER ISSUES WITH TEMPERATURES DROPPING BELOW NORMAL FOR MUCH OF
THE WEEK AS A POLAR AIRMASS OVERSPREAD THE MIDWEST.
&&
.AVIATION...25/18Z
ISSUED AT 1145 AM CST THU DEC 25 2014
VFR CONDITIONS INITIALLY WITH SOUTHERLY FLOW...WITH CLOUD
BASES LOWERING THROUGH THE PERIOD. HAVE BROUGHT A FEW NORTHERN
TAF SITES DOWN INTO THE MVFR RANGE...AND GUIDANCE/MODELS SUGGEST
POTENTIAL FOR FURTHER LOWERING TOWARD THE END OF THE PERIOD.
ALSO HINTS THAT SOME FZDZ IS POSSIBLE ACROSS THE FAR NORTH VERY
LATE IN THE PERIOD...SO WILL CONTINUE TO MONITOR AND MAY HAVE TO
INTRODUCE IF CERTAINTY INCREASES.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
UPDATE...FAB
SHORT TERM...FAB
LONG TERM...COGIL
AVIATION...BEERENDS
AREA FORECAST DISCUSSION
NWS DES MOINES IA
706 AM CST THU DEC 25 2014
.UPDATE...
ISSUED AT 704 AM CST THU DEC 25 2014
LITTLE CHANGE WAS MADE TO THE FORECAST AT THIS POINT. SOME
ADJUSTMENT TO CLOUD COVER DUE TO STRATUS TAILING BACK ACROSS THE
NORTHEAST.
&&
.SHORT TERM /TODAY/...
ISSUED AT 356 AM CST THU DEC 25 2014
SATELLITE IS SHOWING THE STRATUS STEADILY PUSHING TO THE EAST AND
OUT OF CENTRAL IOWA. DES MOINES HAD SCATTERED OUT AROUND 3AM AND
THE CLEARING LINE AS OF THAT TIME RAN FROM ESTHERVILLE TO JUST EAST
OF DES MOINES TO JUST EAST OF CENTERVILLE. BY 12Z THE SOUTH SHOULD
BE CLEARING FROM THE STRATUS. THE NORTH IS A LITTLE MORE
PROBLEMATIC AND I BELIEVE LOCATIONS NORTH OF HIGHWAY 20 WILL SEE
STRATUS FOR A FAIR PART OF THE MORNING.
WHILE THE STRATUS WILL LIKELY BE GONE BY THE AFTERNOON...PRETTY
STRONG WARM ADVECTION IS UNDERWAY AND WILL CONTINUE THROUGH TODAY.
MID AND HIGH CLOUDS CURRENTLY OVER NEBRASKA AND THE DAKOTAS WILL
MOVE INTO IOWA AND WHILE THERE SHOULD BE A FAIR AMOUNT OF SUN AND
PLENTY OF BREAKS IN THE CLOUDS IT WILL NOT BE A BRIGHT SUNNY
DAY...AT LEAST FOR THE MOST PART. SOUNDINGS HANG ON TO LOW LEVEL
MOISTURE AND DO INCREASE MID LEVEL MOISTURE BY THE AFTERNOON WHICH
IS EXPECTED AS THE WARM ADVECTION INCREASES. THE NAM IS MORE
BULLISH WHILE THE GFS DOES NOT HOLD ON TO THE MOISTURE AS MUCH. HI-
RES SHORT TERM MODELS LIKE THE RAP AND THE HRRR ALSO INDICATED LESS
CLOUD COVER TODAY...ESPECIALLY SOUTH.
SFC WINDS WILL BECOME WIDESPREAD 10 TO 20 MPH WITH GUSTS TO 25 OR 30
MPH AT TIMES. TEMPS TODAY WILL BE QUITE NICE WITH HIGHS IN THE MID
30S NORTH TO THE MID 40S SOUTH. ENJOY TODAYS TEMPS BECAUSE MODEL
SOUNDINGS CRASH TEMPS BEGINNING TOMORROW.
.LONG TERM /TONIGHT THROUGH TUESDAY/...
ISSUED AT 356 AM CST THU DEC 25 2014
COLD FRONT WILL SETTLE SLOWLY SOUTHEAST INTO IOWA TONIGHT BUT BULK
OF FORCING WILL HAVE MOVED NORTHEAST OF THE STATE WITH INITIAL
WARM ADVECTION SURGE AND ASSOCIATED SHORTWAVE. LOW CLOUDS WILL
DROP INTO THE FAR NORTHWEST OVERNIGHT BEHIND THE BOUNDARY BENEATH
THE SHALLOW FRONTAL INVERSION. THE FRONT IS EXPECTED TO SLOW ON
FRIDAY AS MAIN SHORTWAVE BEGINS TO EJECT FROM THE INTER-MOUNTAIN
WEST. LOW CLOUDS WILL CONTINUE TO GRADUALLY EXPAND SOUTHEAST
ACROSS THE FORECAST AREA ON LOW LEVEL NORTHWEST WINDS. NAM MOST
AGGRESSIVE WITH DEEPER LOW LEVEL SATURATION WHILE GFS/EURO NOT AS
MOIST. NOT REAL CONFIDENT ABOUT THE POSSIBILITY OF FREEZING
DRIZZLE/DRIZZLE GIVEN THE MODEL DISCREPANCIES BUT HAVE INCLUDED
SOME PATCHY AREAS STARTING LATE MORNING IN THE NORTHWEST PER NAM
GIVEN THE DEEPER SATURATION. THIS SPREAD SLOWLY SOUTHEAST INTO THE
AFTERNOON...HOWEVER THE PRECIPITATION WILL BE VERY LIGHT UNTIL THE
MAIN SYSTEM ARRIVES ON FRIDAY NIGHT.
PRECIPITATION WILL BE ON THE INCREASE FRIDAY NIGHT AS THE MAIN
SHORTWAVE APPROACHES. MID LEVEL QG FORCING INTENSIFIES RAPIDLY
FRIDAY EVENING ACROSS THE WEST AND PROPAGATES PRIMARILY ACROSS THE
WEST AND NORTH OVERNIGHT. THIS AREA WILL SEE THE BEST COVERAGE OF
SNOW OVERNIGHT WITH 1 TO 3 INCHES LIKELY ACROSS THE NORTH...MAINLY
ALONG AND NORTH OF HIGHWAY 20 WITH HIGHEST AMOUNTS ALONG THE
MINNESOTA BORDER. FARTHER SOUTH...ANOTHER PRECIPITATION AREA IS
EXPECTED NEAR THE SURFACE FRONT IN THE FAR SOUTHEAST FORECAST AREA
NEAR OTTUMWA WITH LIGHT RAIN INITIALLY CHANGING TO SNOW LATE.
AMOUNTS WILL REMAIN QUITE LIGHT WITH ONLY A DUSTING OF SNOW.
TEMPERATURES WILL COOL WITH A SURGE OF CANADIAN AIR BEHIND THIS
SYSTEM. HOWEVER...THE BIGGER PUSH OF COLD AIR WILL ARRIVE SUNDAY
NIGHT INTO MONDAY AS A COLD FRONT SLIDES THROUGH THE STATE. THERE
WILL BE SOME THREAT OF VERY LIGHT SNOW ON THE BACKSIDE OF THE
BOUNDARY ON MONDAY...HOWEVER THE PUSH OF COLDER AIR WILL BE THE
BIGGER ISSUES WITH TEMPERATURES DROPPING BELOW NORMAL FOR MUCH OF
THE WEEK AS A POLAR AIRMASS OVERSPREAD THE MIDWEST.
&&
.AVIATION...25/12Z
ISSUED AT 554 AM CST THU DEC 25 2014
STRATUS CURRENTLY FROM JUST EAST OF KMCW TO JUST WEST OF KCID AND
WILL CONTINUE TO PUSH EAST TODAY. MID LEVEL CLOUD COVER WILL
INCREASE IN WARM ADVECTION TODAY PRODUCING VFR CIGS. SOUTHERLY
WINDS WILL INCREASE TODAY IN STRENGTHENING WARM ADVECTION AHEAD OF
THE NEXT SYSTEM WHICH WILL MOVE INTO TAF LOCATIONS BY LATE IN THE
PERIOD. CIGS WILL ONCE AGAIN GO BACK TO IFR WITH A WIND SHIFT TO
THE NORTH.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...FAB
SHORT TERM...FAB
LONG TERM...COGIL
AVIATION...FAB
AREA FORECAST DISCUSSION
NWS DES MOINES IA
554 AM CST THU DEC 25 2014
.SHORT TERM /TODAY/...
ISSUED AT 356 AM CST THU DEC 25 2014
SATELLITE IS SHOWING THE STRATUS STEADILY PUSHING TO THE EAST AND
OUT OF CENTRAL IOWA. DES MOINES HAD SCATTERED OUT AROUND 3AM AND
THE CLEARING LINE AS OF THAT TIME RAN FROM ESTHERVILLE TO JUST EAST
OF DES MOINES TO JUST EAST OF CENTERVILLE. BY 12Z THE SOUTH SHOULD
BE CLEARING FROM THE STRATUS. THE NORTH IS A LITTLE MORE
PROBLEMATIC AND I BELIEVE LOCATIONS NORTH OF HIGHWAY 20 WILL SEE
STRATUS FOR A FAIR PART OF THE MORNING.
WHILE THE STRATUS WILL LIKELY BE GONE BY THE AFTERNOON...PRETTY
STRONG WARM ADVECTION IS UNDERWAY AND WILL CONTINUE THROUGH TODAY.
MID AND HIGH CLOUDS CURRENTLY OVER NEBRASKA AND THE DAKOTAS WILL
MOVE INTO IOWA AND WHILE THERE SHOULD BE A FAIR AMOUNT OF SUN AND
PLENTY OF BREAKS IN THE CLOUDS IT WILL NOT BE A BRIGHT SUNNY
DAY...AT LEAST FOR THE MOST PART. SOUNDINGS HANG ON TO LOW LEVEL
MOISTURE AND DO INCREASE MID LEVEL MOISTURE BY THE AFTERNOON WHICH
IS EXPECTED AS THE WARM ADVECTION INCREASES. THE NAM IS MORE
BULLISH WHILE THE GFS DOES NOT HOLD ON TO THE MOISTURE AS MUCH. HI-
RES SHORT TERM MODELS LIKE THE RAP AND THE HRRR ALSO INDICATED LESS
CLOUD COVER TODAY...ESPECIALLY SOUTH.
SFC WINDS WILL BECOME WIDESPREAD 10 TO 20 MPH WITH GUSTS TO 25 OR 30
MPH AT TIMES. TEMPS TODAY WILL BE QUITE NICE WITH HIGHS IN THE MID
30S NORTH TO THE MID 40S SOUTH. ENJOY TODAYS TEMPS BECAUSE MODEL
SOUNDINGS CRASH TEMPS BEGINNING TOMORROW.
.LONG TERM /TONIGHT THROUGH TUESDAY/...
ISSUED AT 356 AM CST THU DEC 25 2014
COLD FRONT WILL SETTLE SLOWLY SOUTHEAST INTO IOWA TONIGHT BUT BULK
OF FORCING WILL HAVE MOVED NORTHEAST OF THE STATE WITH INITIAL
WARM ADVECTION SURGE AND ASSOCIATED SHORTWAVE. LOW CLOUDS WILL
DROP INTO THE FAR NORTHWEST OVERNIGHT BEHIND THE BOUNDARY BENEATH
THE SHALLOW FRONTAL INVERSION. THE FRONT IS EXPECTED TO SLOW ON
FRIDAY AS MAIN SHORTWAVE BEGINS TO EJECT FROM THE INTER-MOUNTAIN
WEST. LOW CLOUDS WILL CONTINUE TO GRADUALLY EXPAND SOUTHEAST
ACROSS THE FORECAST AREA ON LOW LEVEL NORTHWEST WINDS. NAM MOST
AGGRESSIVE WITH DEEPER LOW LEVEL SATURATION WHILE GFS/EURO NOT AS
MOIST. NOT REAL CONFIDENT ABOUT THE POSSIBILITY OF FREEZING
DRIZZLE/DRIZZLE GIVEN THE MODEL DISCREPANCIES BUT HAVE INCLUDED
SOME PATCHY AREAS STARTING LATE MORNING IN THE NORTHWEST PER NAM
GIVEN THE DEEPER SATURATION. THIS SPREAD SLOWLY SOUTHEAST INTO THE
AFTERNOON...HOWEVER THE PRECIPITATION WILL BE VERY LIGHT UNTIL THE
MAIN SYSTEM ARRIVES ON FRIDAY NIGHT.
PRECIPITATION WILL BE ON THE INCREASE FRIDAY NIGHT AS THE MAIN
SHORTWAVE APPROACHES. MID LEVEL QG FORCING INTENSIFIES RAPIDLY
FRIDAY EVENING ACROSS THE WEST AND PROPAGATES PRIMARILY ACROSS THE
WEST AND NORTH OVERNIGHT. THIS AREA WILL SEE THE BEST COVERAGE OF
SNOW OVERNIGHT WITH 1 TO 3 INCHES LIKELY ACROSS THE NORTH...MAINLY
ALONG AND NORTH OF HIGHWAY 20 WITH HIGHEST AMOUNTS ALONG THE
MINNESOTA BORDER. FARTHER SOUTH...ANOTHER PRECIPITATION AREA IS
EXPECTED NEAR THE SURFACE FRONT IN THE FAR SOUTHEAST FORECAST AREA
NEAR OTTUMWA WITH LIGHT RAIN INITIALLY CHANGING TO SNOW LATE.
AMOUNTS WILL REMAIN QUITE LIGHT WITH ONLY A DUSTING OF SNOW.
TEMPERATURES WILL COOL WITH A SURGE OF CANADIAN AIR BEHIND THIS
SYSTEM. HOWEVER...THE BIGGER PUSH OF COLD AIR WILL ARRIVE SUNDAY
NIGHT INTO MONDAY AS A COLD FRONT SLIDES THROUGH THE STATE. THERE
WILL BE SOME THREAT OF VERY LIGHT SNOW ON THE BACKSIDE OF THE
BOUNDARY ON MONDAY...HOWEVER THE PUSH OF COLDER AIR WILL BE THE
BIGGER ISSUES WITH TEMPERATURES DROPPING BELOW NORMAL FOR MUCH OF
THE WEEK AS A POLAR AIRMASS OVERSPREAD THE MIDWEST.
&&
.AVIATION...25/12Z
ISSUED AT 554 AM CST THU DEC 25 2014
STRATUS CURRENTLY FROM JUST EAST OF KMCW TO JUST WEST OF KCID AND
WILL CONTINUE TO PUSH EAST TODAY. MID LEVEL CLOUD COVER WILL
INCREASE IN WARM ADVECTION TODAY PRODUCING VFR CIGS. SOUTHERLY
WINDS WILL INCREASE TODAY IN STRENGTHENING WARM ADVECTION AHEAD OF
THE NEXT SYSTEM WHICH WILL MOVE INTO TAF LOCATIONS BY LATE IN THE
PERIOD. CIGS WILL ONCE AGAIN GO BACK TO IFR WITH A WIND SHIFT TO
THE NORTH.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...FAB
LONG TERM...COGIL
AVIATION...FAB
AREA FORECAST DISCUSSION
NWS DES MOINES IA
356 AM CST THU DEC 25 2014
.SHORT TERM /TODAY/...
ISSUED AT 356 AM CST THU DEC 25 2014
SATELLITE IS SHOWING THE STRATUS STEADILY PUSHING TO THE EAST AND
OUT OF CENTRAL IOWA. DES MOINES HAD SCATTERED OUT AROUND 3AM AND
THE CLEARING LINE AS OF THAT TIME RAN FROM ESTHERVILLE TO JUST EAST
OF DES MOINES TO JUST EAST OF CENTERVILLE. BY 12Z THE SOUTH SHOULD
BE CLEARING FROM THE STRATUS. THE NORTH IS A LITTLE MORE
PROBLEMATIC AND I BELIEVE LOCATIONS NORTH OF HIGHWAY 20 WILL SEE
STRATUS FOR A FAIR PART OF THE MORNING.
WHILE THE STRATUS WILL LIKELY BE GONE BY THE AFTERNOON...PRETTY
STRONG WARM ADVECTION IS UNDERWAY AND WILL CONTINUE THROUGH TODAY.
MID AND HIGH CLOUDS CURRENTLY OVER NEBRASKA AND THE DAKOTAS WILL
MOVE INTO IOWA AND WHILE THERE SHOULD BE A FAIR AMOUNT OF SUN AND
PLENTY OF BREAKS IN THE CLOUDS IT WILL NOT BE A BRIGHT SUNNY
DAY...AT LEAST FOR THE MOST PART. SOUNDINGS HANG ON TO LOW LEVEL
MOISTURE AND DO INCREASE MID LEVEL MOISTURE BY THE AFTERNOON WHICH
IS EXPECTED AS THE WARM ADVECTION INCREASES. THE NAM IS MORE
BULLISH WHILE THE GFS DOES NOT HOLD ON TO THE MOISTURE AS MUCH. HI-
RES SHORT TERM MODELS LIKE THE RAP AND THE HRRR ALSO INDICATED LESS
CLOUD COVER TODAY...ESPECIALLY SOUTH.
SFC WINDS WILL BECOME WIDESPREAD 10 TO 20 MPH WITH GUSTS TO 25 OR 30
MPH AT TIMES. TEMPS TODAY WILL BE QUITE NICE WITH HIGHS IN THE MID
30S NORTH TO THE MID 40S SOUTH. ENJOY TODAYS TEMPS BECAUSE MODEL
SOUNDINGS CRASH TEMPS BEGINNING TOMORROW.
.LONG TERM /TONIGHT THROUGH TUESDAY/...
ISSUED AT 356 AM CST THU DEC 25 2014
COLD FRONT WILL SETTLE SLOWLY SOUTHEAST INTO IOWA TONIGHT BUT BULK
OF FORCING WILL HAVE MOVED NORTHEAST OF THE STATE WITH INITIAL
WARM ADVECTION SURGE AND ASSOCIATED SHORTWAVE. LOW CLOUDS WILL
DROP INTO THE FAR NORTHWEST OVERNIGHT BEHIND THE BOUNDARY BENEATH
THE SHALLOW FRONTAL INVERSION. THE FRONT IS EXPECTED TO SLOW ON
FRIDAY AS MAIN SHORTWAVE BEGINS TO EJECT FROM THE INTER-MOUNTAIN
WEST. LOW CLOUDS WILL CONTINUE TO GRADUALLY EXPAND SOUTHEAST
ACROSS THE FORECAST AREA ON LOW LEVEL NORTHWEST WINDS. NAM MOST
AGGRESSIVE WITH DEEPER LOW LEVEL SATURATION WHILE GFS/EURO NOT AS
MOIST. NOT REAL CONFIDENT ABOUT THE POSSIBILITY OF FREEZING
DRIZZLE/DRIZZLE GIVEN THE MODEL DISCREPANCIES BUT HAVE INCLUDED
SOME PATCHY AREAS STARTING LATE MORNING IN THE NORTHWEST PER NAM
GIVEN THE DEEPER SATURATION. THIS SPREAD SLOWLY SOUTHEAST INTO THE
AFTERNOON...HOWEVER THE PRECIPITATION WILL BE VERY LIGHT UNTIL THE
MAIN SYSTEM ARRIVES ON FRIDAY NIGHT.
PRECIPITATION WILL BE ON THE INCREASE FRIDAY NIGHT AS THE MAIN
SHORTWAVE APPROACHES. MID LEVEL QG FORCING INTENSIFIES RAPIDLY
FRIDAY EVENING ACROSS THE WEST AND PROPAGATES PRIMARILY ACROSS THE
WEST AND NORTH OVERNIGHT. THIS AREA WILL SEE THE BEST COVERAGE OF
SNOW OVERNIGHT WITH 1 TO 3 INCHES LIKELY ACROSS THE NORTH...MAINLY
ALONG AND NORTH OF HIGHWAY 20 WITH HIGHEST AMOUNTS ALONG THE
MINNESOTA BORDER. FARTHER SOUTH...ANOTHER PRECIPITATION AREA IS
EXPECTED NEAR THE SURFACE FRONT IN THE FAR SOUTHEAST FORECAST AREA
NEAR OTTUMWA WITH LIGHT RAIN INITIALLY CHANGING TO SNOW LATE.
AMOUNTS WILL REMAIN QUITE LIGHT WITH ONLY A DUSTING OF SNOW.
TEMPERATURES WILL COOL WITH A SURGE OF CANADIAN AIR BEHIND THIS
SYSTEM. HOWEVER...THE BIGGER PUSH OF COLD AIR WILL ARRIVE SUNDAY
NIGHT INTO MONDAY AS A COLD FRONT SLIDES THROUGH THE STATE. THERE
WILL BE SOME THREAT OF VERY LIGHT SNOW ON THE BACKSIDE OF THE
BOUNDARY ON MONDAY...HOWEVER THE PUSH OF COLDER AIR WILL BE THE
BIGGER ISSUES WITH TEMPERATURES DROPPING BELOW NORMAL FOR MUCH OF
THE WEEK AS A POLAR AIRMASS OVERSPREAD THE MIDWEST.
&&
.AVIATION...25/06Z
ISSUED AT 1133 PM CST WED DEC 24 2014
HIGH PRESSURE RIDGE OVER IA WILL MOVE TO THE EAST. IFR CONDITIONS
WILL IMPROVE FROM THE WEST AFTER RIDGE PASSAGE WITH CIGS LIFTING
TO VFR AFTER 12Z. VFR CONDITIONS WILL PREVAIL THROUGH CHRISTMAS
DAY INTO THE EVENING.
OUTLOOK...DETERIORATING CONDITIONS FROM THE NORTHWEST AS THE NEXT
FRONTAL SYSTEM APPROACHES FRIDAY. IFR AND MVFR WILL SPREAD INTO
NWRN IA DURING THE DAY...AND OVER THE TAF SITES FRIDAY NIGHT.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...FAB
LONG TERM...COGIL
AVIATION...MS DEC 14
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
524 PM CST FRI DEC 26 2014
...UPDATED FOR AVIATION...
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 258 PM CST FRI DEC 26 2014
THE NAM MODEL SEEMED TO OUTPERFORM THE HRRR WITH RESPECT TO
PRECIP PLACEMENT LATE THIS MORNING AND EARLY AFTERNOON. THE MODEL
WILL CONTINUE TO BE USED AS A GUIDE IN COMBINATION WITH CURRENT
TRENDS TO PLACE POPS AND QPF/SNOW AMOUNTS FOR THE REST
AFTERNOON/EVENING. A DECISION WILL NEED TO BE MADE WHETHER TO
EXTEND EITHER IN TIME AND AREAL COVERAGE OR DROP THE ADVISORY
ALTOGETHER AT 4 PM. AT THIS TIME, EXTENSION DOES NOT APPEAR TO BE
LIKELY. THE NAM INDICATED AN INTSENSIFICATION OF FRONTOGENESIS IN
THE MID TO LATE AFTERNOON, HOWEVER IT IS ASSOCIATED WITH NON
FAVORABLE AGEOSTROPHIC FLOW FOR VERTICAL MOTION. ONCE THE SNOW
BEGINS TO WIND DOWN FROM THE DISSIPATION OF VERTICAL MOTION, CLOUD
CEILING HEIGHTS WILL BEGIN TO INCREASE FROM WEST TO EAST THIS
EVENING. FOG SHOULD NOT BE A BIG CONCERN HEADING INTO THE
OVERNIGHT AS SURFACE BOUNDARY LAYER AIR SEES A BUMP IN DEW POINT
TEMPERATURES (WHICH THE NAM SEEMS TO REFLECT), AS SURFACE WINDS
WILL BE WELL ENOUGH MIXED AND SLIGHTLY DOWNSLOPED.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 327 PM CST FRI DEC 26 2014
MEDIUM RANGE MODELS INDICATE A POSITIVELY TILTED UPPER LEVEL TROUGH
OF LOW PRESSURE SHIFTING EASTWARD OUT OF THE DESERT SOUTHWEST INTO
THE SOUTH PLAINS SUNDAY BRINGING ABOUT A WESTERLY FLOW ALOFT TO THE
WESTERN HIGH PLAINS. A WEAKENING FLOW ALOFT COMBINED WITH A LACK OF
LOW/MID LEVEL MOISTURE WILL RESULT IN DRY CONDITIONS PREVAILING
ACROSS WESTERN KANSAS THROUGH LATE MONDAY MORNING. PRECIP CHANCES
WILL INCREASE A LITTLE MONDAY AFTERNOON AS DEEPENING UPPER LEVEL
TROUGH DROPS SOUTHWARD ACROSS THE PACIFIC NORTHWEST SETTING UP A
DIFLUENT FLOW ALOFT ACROSS THE WESTERN HIGH PLAINS. THIS WILL
COINCIDE WITH ANOTHER STRONG COLD FRONT PUSHING SOUTHWARD ACROSS
WESTERN KANSAS AS THE FLOW ALOFT STRENGTHENS AFTER EXITING THE
TROUGH AXIS OUT WEST. AS A RESULT, SNOW IS LIKELY TO DEVELOP
ACROSS THE HIGH PLAINS OF COLORADO MONDAY WITH THE POTENTIAL FOR
SNOW SPREADING EASTWARD INTO PORTIONS OF WESTERN KANSAS FROM
MONDAY AFTERNOON THROUGH EARLY TUESDAY MORNING. ALTHOUGH IT IS TOO
EARLY TO DETERMINE SNOW AMOUNT POTENTIAL, WEAK QPF SIGNALS SUGGEST
LIGHTER AMOUNTS, IF ANY.
ALTHOUGH REBOUNDING SOMEWHAT, TEMPERATURES WILL REMAIN BELOW NORMAL
SUNDAY WITH COLDER AIR SLOW TO ERODE AS A LEE SIDE TROUGH OF LOW
PRESSURE DEVELOPS ACROSS EASTERN COLORADO. THE GFS/ECMWF SHOW THE
H85 0C ISOTHERM BEGINNING TO EDGE BACK TO THE NORTH BUT REMAINING
WELL SOUTH OF CENTRAL AND MUCH OF SOUTHWEST KANSAS. EVEN WITH
DECREASED CLOUD COVER EXPECTED, LOOK FOR HIGHS ONLY UP INTO THE
30S(F) SUNDAY AFTERNOON WITH NEAR 40F STILL A POSSIBILITY CLOSER TO
THE OKLAHOMA BORDER. THE GFS AND ECMWF CONTINUE TO PROJECT A
STRONG ARCTIC COLD FRONT PUSHING THROUGH WESTERN KANSAS MONDAY
BRINGING ANOTHER ROUND OF COLD AIR SURGING SOUTHWARD INTO THE
REGION EARLY NEXT WEEK. HIGHS COULD BE AS LOW AS THE TEENS(F)
TUESDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 518 PM CST FRI DEC 26 2014
MVFR CIGS ARE FORECAST TO GIVE WAY TO SCATTERED TO BROKEN CIGS
WITH VFR CONDITIONS AFTER 06Z AT KDDC AND KGCK, AND AFTER 12Z AT
KHYS. SURFACE HIGH PRESSURE WILL CONTINUE TO BUILD INTO CENTRAL
PLAINS TONIGHT WITH NORTHWEST WINDS AROUND 10KT.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 18 32 16 38 / 20 0 0 0
GCK 14 31 15 36 / 30 0 0 0
EHA 13 32 16 39 / 20 0 0 0
LBL 17 34 15 39 / 20 0 0 0
HYS 16 29 15 36 / 60 0 0 0
P28 21 38 18 41 / 20 0 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...RUSSELL
LONG TERM...JJOHNSON
AVIATION...KRUSE
AREA FORECAST DISCUSSION
NWS JACKSON KY
1246 PM EST THU DEC 25 2014
.UPDATE...
ISSUED AT 1246 PM EST THU DEC 25 2014
WILL BE UPDATING THE FORECAST PACKAGE TO HANG ONTO CLOUDS JUST A BIT
LONGER AS PESKY LOW SC DECK GRADUALLY DISSIPATES THROUGH THE LATE
AFTERNOON AND EARLY EVENING TIME FRAME. OTHERWISE JUST MINOR TWEAKS
TO THE HOURLY GRIDS TO ACCOUNT FOR LATEST OBSERVATIONS.
UPDATE ISSUED AT 938 AM EST THU DEC 25 2014
UPDATED GRIDS FOR LATEST HOURLY OBS AND TRENDS. THIS RESULTED IN VERY
MINOR CHANGES TO THE FORECAST. OVERALL FORECAST IS IN EXCELLENT SHAPE
THIS CHRISTMAS MORNING. STILL PICKING UP ON SOME PATCHY DRIZZLE IN
THE OBS AND ON RADAR. CLOUD TOP TEMPS SUGGEST THERE IS SOME FLURRY
ACTIVITY OUT THERE AS WELL...MAINLY IN THE HIGHER ELEVATIONS. NO
UPDATE TO THE ZONES PLANNED AT THIS TIME.
UPDATE ISSUED AT 745 AM EST THU DEC 25 2014
HOURLY GRIDS HAVE BEEN FRESHENED UP BASED ON RECENT RADAR AND
OBSERVATION TRENDS. THIS LED TO HOLDING ONTO CHANCES FOR DRIZZLE A
BIT LONGER IN MANY AREAS. FLURRIES WILL ALSO BE POSSIBLE INITIALLY
ABOVE 2000 FEET. HOWEVER...THE MOISTURE WILL BECOME MORE SHALLOW THIS
MORNING AND EVENTUALLY STRATOCU SHOULD BE LEFT BEHIND. THIS STRATOCU
SHOULD BEGIN TO SCATTER OUT BY EARLY TO MID AFTERNOON IN WESTERN
LOCATIONS.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 325 AM EST THU DEC 25 2014
A DEEP CLOSED UPPER LEVEL LOW AND SFC SYSTEM CONTINUES TO DEPART TO
OUR NORTH AND NORTHEAST WITH THE TRAILING UPPER LEVEL TROUGH NOW
WORKING ACROSS PARTS OF THE GREAT LAKES...OH VALLEY AND APPALACHIANS.
MEANWHILE TO THE WEST...A RIDGE EXTENDED FROM THE PACIFIC TO THE
SOUTHWEST OF BAJA INTO THE SOUTHERN AND CENTRAL PLAINS REGION. ALSO
AT THE SFC...A RIDGE OF HIGH PRESSURE EXTENDED NORTH FROM THE WESTERN
GULF OF MEXICO NORTH INTO THE MS VALLEY REGION. SOME SHOWERS...LIKELY
MIXED WITH OR ALL RAIN ABOVE 2000 FEET ARE WORKING FROM THE KY
CUMBERLAND MTNS EAST INTO THE WESTERN VA MOUNTAINS. ADDITIONAL
ISOLATED SHOWERS OR PATCHES OF DRIZZLE HAVE DEVELOPED FURTHER TO THE
WEST NEARER TO THE I 75 CORRIDOR AS THE UPPER LEVEL TROUGH AXIS WORKS
THROUGH THE AREA AND CORE OF THE COLDEST 850 MB AIR AND SLIGHTLY
STEEPER LAPSE RATES MOVE IN. CURRENTLY ACROSS THE HIGH TERRAIN THE TO
OF BLACK MTN AT NEAR 4100 FEET IS 30 DEGREES WHILE THE FLATWOODS
MESONET SITE IN PIKE COUNTY NEAR 2800 FEET IS 34 DEGREES. LOWER
ELEVATION TEMPERATURES ARE GENERALLY IN THE UPPER 30S TO LOWER 40S.
THE PRIMARY WEATHER CONCERN FOR THE SHORT TERM PERIOD IS THE LIGHT
PRECIP THROUGH AROUND DAWN AS THE TROUGH WORKS THROUGH AND THEN THE
LOW LEVEL MOISTURE SUBSEQUENTLY BECOMES MORE SHALLOW AND A PERIOD OF
STRATOCU FOLLOWS. ABOVE 2000 FEET SNOW OR A RAIN AND SNOW MIX IS
ANTICIPATED AS CLOUD TOP TEMPS NEAR THE RETURNS TO OUR WEST ARE
GENERALLY -11C TO -14C OR SUPPORTIVE OF THE PRESENCE OF ICE IN THESE
CLOUDS. ALSO IN THESE AREAS ABOVE 2000 FEET MIN T SHOULD REACH 32 OR
LOWER. LOWER ELEVATION LOCATIONS WILL BOTTOM OUT IN THE MID TO UPPER
30S. THERE ARE AREAS WITH WARMER TEMPS AND ANY LIGHT PRECIP FALLING
FROM THEM WOULD BE MORE OF A DRIZZLE. SOME RECENT SHORT TERM GUIDANCE
SUCH AS THE HRRR AND RAP GUIDANCE SUPPORTS ONE LAST UPTICK IN
COVERAGE OF THIS LIGHT PRECIP AS IT WORKS ACROSS THE REGION OVER THE
NEXT 3 TO 5 HOURS...ENDING NOT LONG AFTER SUNRISE. ACCORDINGLY...A
PRE FIRST PERIOD WAS USED IN THE ZFP AND THE HWO HIGHLIGHTED THE
SMALL CHANCE FOR SNOW SHOWERS INITIALLY FOR THE 4 VA BORDER COUNTIES.
OTHERWISE...BEHIND THE DEPARTING TROUGH...HIGH PRESSURE WILL BUILD
INTO AND THEN ACROSS THE AREA BEFORE SHIFTING TO THE EAST OF THE AREA
ON FRIDAY. THIS WILL LEAD TO GRADUALLY CLEARING SKIES FROM WEST TO
EAST TODAY AND DRY WEATHER FOR TONIGHT AND FRIDAY. THIS PATTERN WILL
FAVOR A RIDGE/VALLEY TEMPERATURE SPLIT FOR TONIGHT WITH THE DEEPER
VALLEY LOCATIONS AND TYPICAL COLD SPOTS REACHING THE MID 20S. A VERY
DRY AIR MASS PROJECTED FOR FRIDAY WILL WARM WELL INTO THE 50S ACROSS
THE LOWER ELEVATIONS WITH A FEW LOCATIONS NEAR THE VA BORDER MAY
REACH 60 OR ABOVE ON A DOWN SLOPE COMPONENT.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 232 AM EST THU DEC 25 2014
CONFIDENCE IS HIGH THROUGH THE WEEKEND AS MODELS REMAIN IN GOOD
AGREEMENT. THE PERIOD WILL START OFF DRY AS HIGH PRESSURE HOLDS INTO
SATURDAY. FRIDAY NIGHT WILL FEATURE ANOTHER NIGHT OF GOOD
RIDGE/VALLEY SPLITS...ESPECIALLY IN THE EAST. WE WILL THEN SEE A
DECENT RECOVERY ON SATURDAY AS HIGHS SOAR TO AROUND 60 WITH THE HELP
OF SUNSHINE. A SHORTWAVE TROUGH WILL PUSH INTO THE OHIO RIVER VALLEY
LATE SATURDAY NIGHT INTO SUNDAY. THIS WILL BRING INCREASING CLOUDS
LATE SATURDAY/SATURDAY NIGHT. RAIN WILL ALSO SPREAD INTO THE AREA
SATURDAY NIGHT AND CONTINUE INTO SUNDAY. FORECAST BECOMES
INCREASINGLY UNCERTAIN BEYOND SUNDAY AS THERE IS SOME QUESTION AS TO
HOW LONG PRECIPITATION CHANCES LINGER. THE LATEST 00Z ECMWF HAS SPED
UP THE SYSTEM WITH PRECIPITATION EXITING BY EARLY MONDAY MORNING.
HOWEVER...12Z GFS CONTINUES TO HOLD PRECIPITATION OVER OUR SOUTHEAST
COUNTIES INTO MONDAY NIGHT. FOR THIS REASON...WILL MAINTAIN SOME
POPS IN THE FORECAST INTO MONDAY NIGHT. HOWEVER...THE HIGHEST POPS
WILL BE CONFINED TO THE PART OF THE FORECAST WHERE THERE IS BETTER
CONFIDENCE SATURDAY NIGHT AND SUNDAY. MODELS REMAIN TOO WARM TO
SUPPORT ANYTHING BUT RAIN THROUGH MONDAY NIGHT.
AFTER MONDAY NIGHT...MODELS HAVE COME INTO BETTER AGREEMENT ON A
LESS ACTIVE PERIOD OF WEATHER. MID/UPPER LEVEL FLOW TURNS MORE
ZONAL. EVEN THE IDEA OF A MID WEEK STORM PER THE LAST TWO RUNS OF
THE ECMWF IS NOW MISSING ON THE LATEST RUN. THUS...GOING TO CUT BACK
ON POPS THROUGH THURSDAY OF NEXT WEEK. IT DOES LOOK LIKE A SYSTEM
MAY FINALLY TAKE SHAPE LATE THURSDAY INTO FRIDAY...BUT THIS IS JUST
BEYOND THE CURRENT FORECAST PERIOD. THE TREND IS CERTAINLY TOWARDS
QUIETER WEATHER NEXT WEEK...SO WILL HAVE TO SEE IF THE MODELS
MAINTAIN THE SYSTEM FOR LATE IN THE WEEK. THE WEATHER SHOULD TREND
TOWARDS NORMAL VALUES NEXT WEEK AS COOLER AIR SLOWLY WORKS INTO THE
AREA AS PRECIPITATION ENDS MONDAY AND MONDAY NIGHT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1246 PM EST THU DEC 25 2014
WIND FLOW AT THE SFC AND ALOFT CONTINUES TO BACK TO THE SOUTHWEST.
LOW MVFR STRATOCU DECK WILL ONLY GRADUALLY DISSIPATE THROUGH THE
FIRST 6 HOURS OR SO OF THE FORECAST. OTHERWISE WE FINALLY CLEAR OUT
WITH LIGHT WINDS...GENERALLY FROM THE SOUTH...SOUTHWEST THROUGH THE
REMAINDER OF THE FORECAST PERIOD.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
UPDATE...RAY
SHORT TERM...JP
LONG TERM...KAS
AVIATION...RAY
AREA FORECAST DISCUSSION
NWS JACKSON KY
938 AM EST THU DEC 25 2014
.UPDATE...
ISSUED AT 938 AM EST THU DEC 25 2014
UPDATED GRIDS FOR LATEST HOURLY OBS AND TRENDS. THIS RESULTED IN VERY
MINOR CHANGES TO THE FORECAST. OVERALL FORECAST IS IN EXCELLENT SHAPE
THIS CHRISTMAS MORNING. STILL PICKING UP ON SOME PATCHY DRIZZLE IN
THE OBS AND ON RADAR. CLOUD TOP TEMPS SUGGEST THERE IS SOME FLURRY
ACTIVITY OUT THERE AS WELL...MAINLY IN THE HIGHER ELEVATIONS. NO
UPDATE TO THE ZONES PLANNED AT THIS TIME.
UPDATE ISSUED AT 745 AM EST THU DEC 25 2014
HOURLY GRIDS HAVE BEEN FRESHENED UP BASED ON RECENT RADAR AND
OBSERVATION TRENDS. THIS LED TO HOLDING ONTO CHANCES FOR DRIZZLE A
BIT LONGER IN MANY AREAS. FLURRIES WILL ALSO BE POSSIBLE INITIALLY
ABOVE 2000 FEET. HOWEVER...THE MOISTURE WILL BECOME MORE SHALLOW THIS
MORNING AND EVENTUALLY STRATOCU SHOULD BE LEFT BEHIND. THIS STRATOCU
SHOULD BEGIN TO SCATTER OUT BY EARLY TO MID AFTERNOON IN WESTERN
LOCATIONS.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 325 AM EST THU DEC 25 2014
A DEEP CLOSED UPPER LEVEL LOW AND SFC SYSTEM CONTINUES TO DEPART TO
OUR NORTH AND NORTHEAST WITH THE TRAILING UPPER LEVEL TROUGH NOW
WORKING ACROSS PARTS OF THE GREAT LAKES...OH VALLEY AND APPALACHIANS.
MEANWHILE TO THE WEST...A RIDGE EXTENDED FROM THE PACIFIC TO THE
SOUTHWEST OF BAJA INTO THE SOUTHERN AND CENTRAL PLAINS REGION. ALSO
AT THE SFC...A RIDGE OF HIGH PRESSURE EXTENDED NORTH FROM THE WESTERN
GULF OF MEXICO NORTH INTO THE MS VALLEY REGION. SOME SHOWERS...LIKELY
MIXED WITH OR ALL RAIN ABOVE 2000 FEET ARE WORKING FROM THE KY
CUMBERLAND MTNS EAST INTO THE WESTERN VA MOUNTAINS. ADDITIONAL
ISOLATED SHOWERS OR PATCHES OF DRIZZLE HAVE DEVELOPED FURTHER TO THE
WEST NEARER TO THE I 75 CORRIDOR AS THE UPPER LEVEL TROUGH AXIS WORKS
THROUGH THE AREA AND CORE OF THE COLDEST 850 MB AIR AND SLIGHTLY
STEEPER LAPSE RATES MOVE IN. CURRENTLY ACROSS THE HIGH TERRAIN THE TO
OF BLACK MTN AT NEAR 4100 FEET IS 30 DEGREES WHILE THE FLATWOODS
MESONET SITE IN PIKE COUNTY NEAR 2800 FEET IS 34 DEGREES. LOWER
ELEVATION TEMPERATURES ARE GENERALLY IN THE UPPER 30S TO LOWER 40S.
THE PRIMARY WEATHER CONCERN FOR THE SHORT TERM PERIOD IS THE LIGHT
PRECIP THROUGH AROUND DAWN AS THE TROUGH WORKS THROUGH AND THEN THE
LOW LEVEL MOISTURE SUBSEQUENTLY BECOMES MORE SHALLOW AND A PERIOD OF
STRATOCU FOLLOWS. ABOVE 2000 FEET SNOW OR A RAIN AND SNOW MIX IS
ANTICIPATED AS CLOUD TOP TEMPS NEAR THE RETURNS TO OUR WEST ARE
GENERALLY -11C TO -14C OR SUPPORTIVE OF THE PRESENCE OF ICE IN THESE
CLOUDS. ALSO IN THESE AREAS ABOVE 2000 FEET MIN T SHOULD REACH 32 OR
LOWER. LOWER ELEVATION LOCATIONS WILL BOTTOM OUT IN THE MID TO UPPER
30S. THERE ARE AREAS WITH WARMER TEMPS AND ANY LIGHT PRECIP FALLING
FROM THEM WOULD BE MORE OF A DRIZZLE. SOME RECENT SHORT TERM GUIDANCE
SUCH AS THE HRRR AND RAP GUIDANCE SUPPORTS ONE LAST UPTICK IN
COVERAGE OF THIS LIGHT PRECIP AS IT WORKS ACROSS THE REGION OVER THE
NEXT 3 TO 5 HOURS...ENDING NOT LONG AFTER SUNRISE. ACCORDINGLY...A
PRE FIRST PERIOD WAS USED IN THE ZFP AND THE HWO HIGHLIGHTED THE
SMALL CHANCE FOR SNOW SHOWERS INITIALLY FOR THE 4 VA BORDER COUNTIES.
OTHERWISE...BEHIND THE DEPARTING TROUGH...HIGH PRESSURE WILL BUILD
INTO AND THEN ACROSS THE AREA BEFORE SHIFTING TO THE EAST OF THE AREA
ON FRIDAY. THIS WILL LEAD TO GRADUALLY CLEARING SKIES FROM WEST TO
EAST TODAY AND DRY WEATHER FOR TONIGHT AND FRIDAY. THIS PATTERN WILL
FAVOR A RIDGE/VALLEY TEMPERATURE SPLIT FOR TONIGHT WITH THE DEEPER
VALLEY LOCATIONS AND TYPICAL COLD SPOTS REACHING THE MID 20S. A VERY
DRY AIRMASS PROJECTED FOR FRIDAY WILL WARM WELL INTO THE 50S ACROSS
THE LOWER ELEVATIONS WITH A FEW LOCATIONS NEAR THE VA BORDER MAY
REACH 60 OR ABOVE ON A DOWNSLOPE COMPONENT.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 232 AM EST THU DEC 25 2014
CONFIDENCE IS HIGH THROUGH THE WEEKEND AS MODELS REMAIN IN GOOD
AGREEMENT. THE PERIOD WILL START OFF DRY AS HIGH PRESSURE HOLDS INTO
SATURDAY. FRIDAY NIGHT WILL FEATURE ANOTHER NIGHT OF GOOD
RIDGE/VALLEY SPLITS...ESPECIALLY IN THE EAST. WE WILL THEN SEE A
DECENT RECOVERY ON SATURDAY AS HIGHS SOAR TO AROUND 60 WITH THE HELP
OF SUNSHINE. A SHORTWAVE TROUGH WILL PUSH INTO THE OHIO RIVER VALLEY
LATE SATURDAY NIGHT INTO SUNDAY. THIS WILL BRING INCREASING CLOUDS
LATE SATURDAY/SATURDAY NIGHT. RAIN WILL ALSO SPREAD INTO THE AREA
SATURDAY NIGHT AND CONTINUE INTO SUNDAY. FORECAST BECOMES
INCREASINGLY UNCERTAIN BEYOND SUNDAY AS THERE IS SOME QUESTION AS TO
HOW LONG PRECIPITATION CHANCES LINGER. THE LATEST 00Z ECMWF HAS SPED
UP THE SYSTEM WITH PRECIPITATION EXITING BY EARLY MONDAY MORNING.
HOWEVER...12Z GFS CONTINUES TO HOLD PRECIPITATION OVER OUR SOUTHEAST
COUNTIES INTO MONDAY NIGHT. FOR THIS REASON...WILL MAINTAIN SOME
POPS IN THE FORECAST INTO MONDAY NIGHT. HOWEVER...THE HIGHEST POPS
WILL BE CONFINED TO THE PART OF THE FORECAST WHERE THERE IS BETTER
CONFIDENCE SATURDAY NIGHT AND SUNDAY. MODELS REMAIN TOO WARM TO
SUPPORT ANYTHING BUT RAIN THROUGH MONDAY NIGHT.
AFTER MONDAY NIGHT...MODELS HAVE COME INTO BETTER AGREEMENT ON A
LESS ACTIVE PERIOD OF WEATHER. MID/UPPER LEVEL FLOW TURNS MORE
ZONAL. EVEN THE IDEA OF A MID WEEK STORM PER THE LAST TWO RUNS OF
THE ECMWF IS NOW MISSING ON THE LATEST RUN. THUS...GOING TO CUT BACK
ON POPS THROUGH THURSDAY OF NEXT WEEK. IT DOES LOOK LIKE A SYSTEM
MAY FINALLY TAKE SHAPE LATE THURSDAY INTO FRIDAY...BUT THIS IS JUST
BEYOND THE CURRENT FORECAST PERIOD. THE TREND IS CERTAINLY TOWARDS
QUIETER WEATHER NEXT WEEK...SO WILL HAVE TO SEE IF THE MODELS
MAINTAIN THE SYSTEM FOR LATE IN THE WEEK. THE WEATHER SHOULD TREND
TOWARDS NORMAL VALUES NEXT WEEK AS COOLER AIR SLOWLY WORKS INTO THE
AREA AS PRECIPITATION ENDS MONDAY AND MONDAY NIGHT.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 735 AM EST THU DEC 25 2014
AS AN UPPER LEVEL TROUGH DEPARTS THE REGION AND LOW LEVEL MOISTURE
REMAINS...DRIZZLE WILL BE POSSIBLE EARLY AT THE TAF SITES WITH LITTLE
OR NO REDUCTION IN VIS. MVFR CIGS ARE EXPECTED...HOWEVER...IN MOST
AREAS FOR THE FIRST 6 HOURS OF THE PERIOD. AS RIDGING BUILDS INTO
THE AREA...CIGS WILL IMPROVE TO VFR FROM WEST TO EAST AND THEN REMAIN
THERE THROUGH THE END OF THE PERIOD. WINDS WILL REMAIN SOUTHWEST TO
WEST SOUTHWEST AND GENERALLY LIGHT THROUGH THE PERIOD.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
UPDATE...RAY
SHORT TERM...JP
LONG TERM...KAS
AVIATION...JP
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
755 AM EST THU DEC 25 2014
.UPDATE...
ISSUED AT 745 AM EST THU DEC 25 2014
HOURLY GRIDS HAVE BEEN FRESHENED UP BASED ON RECENT RADAR AND
OBSERVATION TRENDS. THIS LED TO HOLDING ONTO CHANCES FOR DRIZZLE A
BIT LONGER IN MANY AREAS. FLURRIES WILL ALSO BE POSSIBLE INITIALLY
ABOVE 2000 FEET. HOWEVER...THE MOISTURE WILL BECOME MORE SHALLOW THIS
MORNING AND EVENTUALLY STRATOCU SHOULD BE LEFT BEHIND. THIS STRATOCU
SHOULD BEGIN TO SCATTER OUT BY EARLY TO MID AFTERNOON IN WESTERN
LOCATIONS.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 325 AM EST THU DEC 25 2014
A DEEP CLOSED UPPER LEVEL LOW AND SFC SYSTEM CONTINUES TO DEPART TO
OUR NORTH AND NORTHEAST WITH THE TRAILING UPPER LEVEL TROUGH NOW
WORKING ACROSS PARTS OF THE GREAT LAKES...OH VALLEY AND APPALACHIANS.
MEANWHILE TO THE WEST...A RIDGE EXTENDED FROM THE PACIFIC TO THE
SOUTHWEST OF BAJA INTO THE SOUTHERN AND CENTRAL PLAINS REGION. ALSO
AT THE SFC...A RIDGE OF HIGH PRESSURE EXTENDED NORTH FROM THE WESTERN
GULF OF MEXICO NORTH INTO THE MS VALLEY REGION. SOME SHOWERS...LIKELY
MIXED WITH OR ALL RAIN ABOVE 2000 FEET ARE WORKING FROM THE KY
CUMBERLAND MTNS EAST INTO THE WESTERN VA MOUNTAINS. ADDITIONAL
ISOLATED SHOWERS OR PATCHES OF DRIZZLE HAVE DEVELOPED FURTHER TO THE
WEST NEARER TO THE I 75 CORRIDOR AS THE UPPER LEVEL TROUGH AXIS WORKS
THROUGH THE AREA AND CORE OF THE COLDEST 850 MB AIR AND SLIGHTLY
STEEPER LAPSE RATES MOVE IN. CURRENTLY ACROSS THE HIGH TERRAIN THE TO
OF BLACK MTN AT NEAR 4100 FEET IS 30 DEGREES WHILE THE FLATWOODS
MESONET SITE IN PIKE COUNTY NEAR 2800 FEET IS 34 DEGREES. LOWER
ELEVATION TEMPERATURES ARE GENERALLY IN THE UPPER 30S TO LOWER 40S.
THE PRIMARY WEATHER CONCERN FOR THE SHORT TERM PERIOD IS THE LIGHT
PRECIP THROUGH AROUND DAWN AS THE TROUGH WORKS THROUGH AND THEN THE
LOW LEVEL MOISTURE SUBSEQUENTLY BECOMES MORE SHALLOW AND A PERIOD OF
STRATOCU FOLLOWS. ABOVE 2000 FEET SNOW OR A RAIN AND SNOW MIX IS
ANTICIPATED AS CLOUD TOP TEMPS NEAR THE RETURNS TO OUR WEST ARE
GENERALLY -11C TO -14C OR SUPPORTIVE OF THE PRESENCE OF ICE IN THESE
CLOUDS. ALSO IN THESE AREAS ABOVE 2000 FEET MIN T SHOULD REACH 32 OR
LOWER. LOWER ELEVATION LOCATIONS WILL BOTTOM OUT IN THE MID TO UPPER
30S. THERE ARE AREAS WITH WARMER TEMPS AND ANY LIGHT PRECIP FALLING
FROM THEM WOULD BE MORE OF A DRIZZLE. SOME RECENT SHORT TERM GUIDANCE
SUCH AS THE HRRR AND RAP GUIDANCE SUPPORTS ONE LAST UPTICK IN
COVERAGE OF THIS LIGHT PRECIP AS IT WORKS ACROSS THE REGION OVER THE
NEXT 3 TO 5 HOURS...ENDING NOT LONG AFTER SUNRISE. ACCORDINGLY...A
PRE FIRST PERIOD WAS USED IN THE ZFP AND THE HWO HIGHLIGHTED THE
SMALL CHANCE FOR SNOW SHOWERS INITIALLY FOR THE 4 VA BORDER COUNTIES.
OTHERWISE...BEHIND THE DEPARTING TROUGH...HIGH PRESSURE WILL BUILD
INTO AND THEN ACROSS THE AREA BEFORE SHIFTING TO THE EAST OF THE AREA
ON FRIDAY. THIS WILL LEAD TO GRADUALLY CLEARING SKIES FROM WEST TO
EAST TODAY AND DRY WEATHER FOR TONIGHT AND FRIDAY. THIS PATTERN WILL
FAVOR A RIDGE/VALLEY TEMPERATURE SPLIT FOR TONIGHT WITH THE DEEPER
VALLEY LOCATIONS AND TYPICAL COLD SPOTS REACHING THE MID 20S. A VERY
DRY AIRMASS PROJECTED FOR FRIDAY WILL WARM WELL INTO THE 50S ACROSS
THE LOWER ELEVATIONS WITH A FEW LOCATIONS NEAR THE VA BORDER MAY
REACH 60 OR ABOVE ON A DOWNSLOPE COMPONENT.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 232 AM EST THU DEC 25 2014
CONFIDENCE IS HIGH THROUGH THE WEEKEND AS MODELS REMAIN IN GOOD
AGREEMENT. THE PERIOD WILL START OFF DRY AS HIGH PRESSURE HOLDS INTO
SATURDAY. FRIDAY NIGHT WILL FEATURE ANOTHER NIGHT OF GOOD
RIDGE/VALLEY SPLITS...ESPECIALLY IN THE EAST. WE WILL THEN SEE A
DECENT RECOVERY ON SATURDAY AS HIGHS SOAR TO AROUND 60 WITH THE HELP
OF SUNSHINE. A SHORTWAVE TROUGH WILL PUSH INTO THE OHIO RIVER VALLEY
LATE SATURDAY NIGHT INTO SUNDAY. THIS WILL BRING INCREASING CLOUDS
LATE SATURDAY/SATURDAY NIGHT. RAIN WILL ALSO SPREAD INTO THE AREA
SATURDAY NIGHT AND CONTINUE INTO SUNDAY. FORECAST BECOMES
INCREASINGLY UNCERTAIN BEYOND SUNDAY AS THERE IS SOME QUESTION AS TO
HOW LONG PRECIPITATION CHANCES LINGER. THE LATEST 00Z ECMWF HAS SPED
UP THE SYSTEM WITH PRECIPITATION EXITING BY EARLY MONDAY MORNING.
HOWEVER...12Z GFS CONTINUES TO HOLD PRECIPITATION OVER OUR SOUTHEAST
COUNTIES INTO MONDAY NIGHT. FOR THIS REASON...WILL MAINTAIN SOME
POPS IN THE FORECAST INTO MONDAY NIGHT. HOWEVER...THE HIGHEST POPS
WILL BE CONFINED TO THE PART OF THE FORECAST WHERE THERE IS BETTER
CONFIDENCE SATURDAY NIGHT AND SUNDAY. MODELS REMAIN TOO WARM TO
SUPPORT ANYTHING BUT RAIN THROUGH MONDAY NIGHT.
AFTER MONDAY NIGHT...MODELS HAVE COME INTO BETTER AGREEMENT ON A
LESS ACTIVE PERIOD OF WEATHER. MID/UPPER LEVEL FLOW TURNS MORE
ZONAL. EVEN THE IDEA OF A MID WEEK STORM PER THE LAST TWO RUNS OF
THE ECMWF IS NOW MISSING ON THE LATEST RUN. THUS...GOING TO CUT BACK
ON POPS THROUGH THURSDAY OF NEXT WEEK. IT DOES LOOK LIKE A SYSTEM
MAY FINALLY TAKE SHAPE LATE THURSDAY INTO FRIDAY...BUT THIS IS JUST
BEYOND THE CURRENT FORECAST PERIOD. THE TREND IS CERTAINLY TOWARDS
QUIETER WEATHER NEXT WEEK...SO WILL HAVE TO SEE IF THE MODELS
MAINTAIN THE SYSTEM FOR LATE IN THE WEEK. THE WEATHER SHOULD TREND
TOWARDS NORMAL VALUES NEXT WEEK AS COOLER AIR SLOWLY WORKS INTO THE
AREA AS PRECIPITATION ENDS MONDAY AND MONDAY NIGHT.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 735 AM EST THU DEC 25 2014
AS AN UPPER LEVEL TROUGH DEPARTS THE REGION AND LOW LEVEL MOISTURE
REMAINS...DRIZZLE WILL BE POSSIBLE EARLY AT THE TAF SITES WITH LITTLE
OR NO REDUCTION IN VIS. MVFR CIGS ARE EXPECTED...HOWEVER...IN MOST
AREAS FOR THE FIRST 6 HOURS OF THE PERIOD. AS RIDGING BUILDS INTO
THE AREA...CIGS WILL IMPROVE TO VFR FROM WEST TO EAST AND THEN REMAIN
THERE THROUGH THE END OF THE PERIOD. WINDS WILL REMAIN SOUTHWEST TO
WEST SOUTHWEST AND GENERALLY LIGHT THROUGH THE PERIOD.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JP
SHORT TERM...JP
LONG TERM...KAS
AVIATION...JP
AREA FORECAST DISCUSSION
NWS JACKSON KY
326 AM EST THU DEC 25 2014
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 325 AM EST THU DEC 25 2014
A DEEP CLOSED UPPER LEVEL LOW AND SFC SYSTEM CONTINUES TO DEPART TO
OUR NORTH AND NORTHEAST WITH THE TRAILING UPPER LEVEL TROUGH NOW
WORKING ACROSS PARTS OF THE GREAT LAKES...OH VALLEY AND APPALACHIANS.
MEANWHILE TO THE WEST...A RIDGE EXTENDED FROM THE PACIFIC TO THE
SOUTHWEST OF BAJA INTO THE SOUTHERN AND CENTRAL PLAINS REGION. ALSO
AT THE SFC...A RIDGE OF HIGH PRESSURE EXTENDED NORTH FROM THE WESTERN
GULF OF MEXICO NORTH INTO THE MS VALLEY REGION. SOME SHOWERS...LIKELY
MIXED WITH OR ALL RAIN ABOVE 2000 FEET ARE WORKING FROM THE KY
CUMBERLAND MTNS EAST INTO THE WESTERN VA MOUNTAINS. ADDITIONAL
ISOLATED SHOWERS OR PATCHES OF DRIZZLE HAVE DEVELOPED FURTHER TO THE
WEST NEARER TO THE I 75 CORRIDOR AS THE UPPER LEVEL TROUGH AXIS WORKS
THROUGH THE AREA AND CORE OF THE COLDEST 850 MB AIR AND SLIGHTLY
STEEPER LAPSE RATES MOVE IN. CURRENTLY ACROSS THE HIGH TERRAIN THE TO
OF BLACK MTN AT NEAR 4100 FEET IS 30 DEGREES WHILE THE FLATWOODS
MESONET SITE IN PIKE COUNTY NEAR 2800 FEET IS 34 DEGREES. LOWER
ELEVATION TEMPERATURES ARE GENERALLY IN THE UPPER 30S TO LOWER 40S.
THE PRIMARY WEATHER CONCERN FOR THE SHORT TERM PERIOD IS THE LIGHT
PRECIP THROUGH AROUND DAWN AS THE TROUGH WORKS THROUGH AND THEN THE
LOW LEVEL MOISTURE SUBSEQUENTLY BECOMES MORE SHALLOW AND A PERIOD OF
STRATOCU FOLLOWS. ABOVE 2000 FEET SNOW OR A RAIN AND SNOW MIX IS
ANTICIPATED AS CLOUD TOP TEMPS NEAR THE RETURNS TO OUR WEST ARE
GENERALLY -11C TO -14C OR SUPPORTIVE OF THE PRESENCE OF ICE IN THESE
CLOUDS. ALSO IN THESE AREAS ABOVE 2000 FEET MIN T SHOULD REACH 32 OR
LOWER. LOWER ELEVATION LOCATIONS WILL BOTTOM OUT IN THE MID TO UPPER
30S. THERE ARE AREAS WITH WARMER TEMPS AND ANY LIGHT PRECIP FALLING
FROM THEM WOULD BE MORE OF A DRIZZLE. SOME RECENT SHORT TERM GUIDANCE
SUCH AS THE HRRR AND RAP GUIDANCE SUPPORTS ONE LAST UPTICK IN
COVERAGE OF THIS LIGHT PRECIP AS IT WORKS ACROSS THE REGION OVER THE
NEXT 3 TO 5 HOURS...ENDING NOT LONG AFTER SUNRISE. ACCORDINGLY...A
PRE FIRST PERIOD WAS USED IN THE ZFP AND THE HWO HIGHLIGHTED THE
SMALL CHANCE FOR SNOW SHOWERS INITIALLY FOR THE 4 VA BORDER COUNTIES.
OTHERWISE...BEHIND THE DEPARTING TROUGH...HIGH PRESSURE WILL BUILD
INTO AND THEN ACROSS THE AREA BEFORE SHIFTING TO THE EAST OF THE AREA
ON FRIDAY. THIS WILL LEAD TO GRADUALLY CLEARING SKIES FROM WEST TO
EAST TODAY AND DRY WEATHER FOR TONIGHT AND FRIDAY. THIS PATTERN WILL
FAVOR A RIDGE/VALLEY TEMPERATURE SPLIT FOR TONIGHT WITH THE DEEPER
VALLEY LOCATIONS AND TYPICAL COLD SPOTS REACHING THE MID 20S. A VERY
DRY AIRMASS PROJECTED FOR FRIDAY WILL WARM WELL INTO THE 50S ACROSS
THE LOWER ELEVATIONS WITH A FEW LOCATIONS NEAR THE VA BORDER MAY
REACH 60 OR ABOVE ON A DOWNSLOPE COMPONENT.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 232 AM EST THU DEC 25 2014
CONFIDENCE IS HIGH THROUGH THE WEEKEND AS MODELS REMAIN IN GOOD
AGREEMENT. THE PERIOD WILL START OFF DRY AS HIGH PRESSURE HOLDS INTO
SATURDAY. FRIDAY NIGHT WILL FEATURE ANOTHER NIGHT OF GOOD
RIDGE/VALLEY SPLITS...ESPECIALLY IN THE EAST. WE WILL THEN SEE A
DECENT RECOVERY ON SATURDAY AS HIGHS SOAR TO AROUND 60 WITH THE HELP
OF SUNSHINE. A SHORTWAVE TROUGH WILL PUSH INTO THE OHIO RIVER VALLEY
LATE SATURDAY NIGHT INTO SUNDAY. THIS WILL BRING INCREASING CLOUDS
LATE SATURDAY/SATURDAY NIGHT. RAIN WILL ALSO SPREAD INTO THE AREA
SATURDAY NIGHT AND CONTINUE INTO SUNDAY. FORECAST BECOMES
INCREASINGLY UNCERTAIN BEYOND SUNDAY AS THERE IS SOME QUESTION AS TO
HOW LONG PRECIPITATION CHANCES LINGER. THE LATEST 00Z ECMWF HAS SPED
UP THE SYSTEM WITH PRECIPITATION EXITING BY EARLY MONDAY MORNING.
HOWEVER...12Z GFS CONTINUES TO HOLD PRECIPITATION OVER OUR SOUTHEAST
COUNTIES INTO MONDAY NIGHT. FOR THIS REASON...WILL MAINTAIN SOME
POPS IN THE FORECAST INTO MONDAY NIGHT. HOWEVER...THE HIGHEST POPS
WILL BE CONFINED TO THE PART OF THE FORECAST WHERE THERE IS BETTER
CONFIDENCE SATURDAY NIGHT AND SUNDAY. MODELS REMAIN TOO WARM TO
SUPPORT ANYTHING BUT RAIN THROUGH MONDAY NIGHT.
AFTER MONDAY NIGHT...MODELS HAVE COME INTO BETTER AGREEMENT ON A
LESS ACTIVE PERIOD OF WEATHER. MID/UPPER LEVEL FLOW TURNS MORE
ZONAL. EVEN THE IDEA OF A MID WEEK STORM PER THE LAST TWO RUNS OF
THE ECMWF IS NOW MISSING ON THE LATEST RUN. THUS...GOING TO CUT BACK
ON POPS THROUGH THURSDAY OF NEXT WEEK. IT DOES LOOK LIKE A SYSTEM
MAY FINALLY TAKE SHAPE LATE THURSDAY INTO FRIDAY...BUT THIS IS JUST
BEYOND THE CURRENT FORECAST PERIOD. THE TREND IS CERTAINLY TOWARDS
QUIETER WEATHER NEXT WEEK...SO WILL HAVE TO SEE IF THE MODELS
MAINTAIN THE SYSTEM FOR LATE IN THE WEEK. THE WEATHER SHOULD TREND
TOWARDS NORMAL VALUES NEXT WEEK AS COOLER AIR SLOWLY WORKS INTO THE
AREA AS PRECIPITATION ENDS MONDAY AND MONDAY NIGHT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 130 AM EST THU DEC 25 2014
AS AN UPPER LEVEL TROUGH WORKS ACROSS THE REGION AND LOW LEVEL
MOISTURE REMAINS...AND DRIZZLE AND SOME ISOLATED SHOWERS ALONG WITH
CIGS IN THE MVFR/FUEL ALTERNATE RANGE WILL LINGER THROUGH ABOUT
12Z. ANY LINGERING LIGHT PRECIP SHOULD END BETWEEN 12Z AND 18Z. MVFR
CIGS SHOULD LINGER AS LONG AS 18Z OR LATER IN THE EAST...BUT AS
RIDGING BUILDS INTO THE AREA...CIGS WILL IMPROVE TO VFR FROM WEST TO
EAST. WINDS WILL REMAIN SOUTHWEST TO WEST SOUTHWEST FOR THE FIRST 12
HOURS OF THE PERIOD AND THEN BECOME LIGHT AND VARIABLE AS THE CENTER
OF HIGH PRESSURE NEARS.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...JP
LONG TERM...KAS
AVIATION...JP
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
1109 PM EST WED DEC 24 2014
.SYNOPSIS...
STRENGTHENING LOW PRESSURE WILL LIFT INTO THE GREAT LAKES
TONIGHT...BRINGING A COLD FRONT ACROSS THE REGION. MILD SOUTHERN
HIGH PRESSURE WILL MOVE IN FOR THE END OF THE WEEK. A WEAK COLD
FRONT WILL PUSH IN FROM THE NORTHWEST SUNDAY. THEN...LOW PRESSURE
FROM THE DEEP SOUTH WILL RIDE UP ALONG THAT FRONT AND OVER THE
REGION EARLY NEXT WEEK. COLDER HIGH PRESSURE WILL FOLLOW FOR MID
WEEK.
&&
.NEAR TERM /THROUGH THURSDAY/...
1109PM UPDATE...DENSE FOG ADVISORY CANCELLED.
02Z WATER VAPOR IMAGERY INDICATING CENTER OF SFC LOW PIVOTING
THROUGH GREAT LAKES REGION...WITH ASSOCIATED COLD FRONT EXTENDING
SOUTH OVER WESTERN PA/CENTRAL WV. WARM FRONT SITUATED TO THE EAST
NOW...TAKING THE LIGHT RAIN WITH IT. MOIST AIRMASS IN PLACE HAS
RESULTED IN WIDESPREAD FOG WITH AREAS OF DENSE FOG MAINLY EAST OF
BLUE RIDGE. CONTINUING DENSE FOG ADV HERE TO ACCOUNT FOR VIS BEING
REDUCED TO 1/4 MILE OR LESS. AS THE PCPN MOVES IN...ENOUGH MIXING
SHOULD OCCUR TO IMPROVE VIS TO AT LEAST A MILE OR MORE.
A LINE OF SHOWERS WITH EMBEDDED HEAVIER SHOWERS NOTED RIGHT ALONG
THE COLD FRONT. ISO SVR TSTMS HAD BEEN OBSERVED IN THE LINE
EARLIER THIS EVENING...BUT WITH LOSS OF ANY INSTABILITY...WHICH
WAS MINIMAL TO BEGIN...NOT ANTICIPATING ANY THUNDER TO EXTEND INTO
OUR CWA. MATCHING WITH LATEST HRRR RUN AND TIMING OF THE
RADAR...STEP THE PCPN ACROSS DURING THE OVERNIGHT HOURS. HRRR ALSO
SUGGESTIVE OF A BIG WAVE OF PCPN COMING UP FROM THE SOUTH AHEAD OF
THIS LINE. WITH THE MOISTURE IN PLACE AND DECENT FORCING ALOFT NOT
QUESTIONING THE FORMATION OF THESE SHOWERS...JUST THE
INTENSITY/COVERAGE. AS SUCH...KEPT LIGHT SHOWER MENTION...WITH THE
PCPN TAPERING OFF FROM THE WEST THROUGH THE DAYLIGHT HOURS.
EXPECTING ALL PCPN TO HAVE CLEARED THE AREA BY 12Z.
ANOTHER CONCERN FOR THE NIGHT IS A WIND ADVISORY IN PLACE FOR THE
POTOMAC HIGHLANDS. STRONG LLJ EXPECTED TO MOVE WITH WINDS AT 850MB
45-55 KTS. WITH THE HIGHER ELEVATIONS...COULD SEE SOME OF THESE
STRONGER WINDS IMPACT THE AREA. WOULD ALSO LIKE TO NOTE THE
HEAVIER SHOWERS MOVING THROUGH WITH THE COLD FRONT COULD BRING
DOWN HEAVIER GUSTS. RIGHT NOW THE ADVISORY GOES THROUGH 11Z...BUT
COULD VERY WELL SEE IT END SOONER WITH THE STRONGEST LLJ WINDS
LOOKING TO MOVE THROUGH THAT AREA BY 08Z.
BREEZY CONDS WL RESIDE BHD CDFNT...W/ BETTER MIXING IN PLACE. SOURCE
RGN OF AMS NOT THAT COLD...AND WL HV DOWNSLOPING WNDS. THEREFORE...MAXT
TMRW SHUD BE SIMLR TO TDA...OR PERHAPS A PINCH WARMER. MRNG CLDS
FM PVA WL QUICKLY ERODE. MOSUN FOR THE REST OF THE DAY.
UPSLOPE CONDS GOOD FOR CONTD CLDCVR ALONG THE WRN SLOPES...BUT LACK
OF MSTR NOT FVRBL FOR PRODUCING PCPN. MTN POPS THU STILL CAPPED AT
CHC...AND HV PTYPE MIX RA/SN.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
AFTER THE MULTI-DAY PERIOD OF INFLUENCE FROM ANOTHER MONSTROUSLY
LARGE LOW PRESSURE SYSTEM...BY THURS NIGHT - WE WILL BE ON THE CUSP
OF A MULTI-DAY REPRIEVE...AT LEAST A COUPLE OF DAYS. IN THE WAKE OF
THE EXITING LOW...SFC HIGH PRESSURE WILL BUILD IN TO OUR SOUTH...
WHICH IS AN IMPORTANT KEY BECAUSE IT WILL SPREAD WARMER TEMPS UP THE
ERN SEABOARD INTO THE WEEKEND. FRIDAY WILL BE CLEAR AND QUIET. AFTER
A BREEZY/WINDY THURSDAY...WINDS WILL DROP OFF TO A LIGHT SLY FLOW.
ALTHOUGH NOT AN INCREDIBLY WARM DAY...MAX TEMPS ON FRI SHOULD REACH
5-10F ABOVE AVG FOR LATE DEC.
WHILE THE HIGH ROLLS OFF THE CAROLINA COAST INTO SATURDAY...SLY FLOW
WILL AGAIN BRING IN SLIGHTLY WARMER AIR W/ MAX TEMPS A BIT HIGHER
THAN FRIDAY...TOPPING OUT IN THE M-U50S. ANOTHER LOW PRESSURE WAVE
WILL SET UP OVER THE SRN PLAINS/LOWER MS VLY. GULF COAST MOISTURE
WILL AGAIN BE TAPPED FOR THE EARLY STAGES OF THIS NEXT SYSTEM...BUT
IN TERMS OF NORTHWARD EXTENT - IT WILL HAVE TROUBLE W/ SECONDARY
WAVES COMING IN FROM THE NW. 12Z RUNS OF THE GFS/EURO ARE IN THE
CLOSEST ALIGNMENT W/ EACH OTHER IN THE PAST FEW DAYS AS TO THE
INTERACTIONS/PROGRESSIONS OF THESE FEATURES. A STRONG ENOUGH UPPER
JET WILL TRANSPORT THE SHEARED EDGE OF THE GULF MOISTURE UP ACROSS
THE UPPER MIDWEST LATE SAT NIGHT. HOWEVER...A POTENT UPPER LOW
SLIDING JUST SOUTH OF HUDSON BAY WILL TAKE THIS NRN MOISTURE UP AND
OVER THE REGION BEFORE THE SRN SYSTEM CAN GET FULLY ORGANIZED.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
HIGH PRESSURE ALONG THE MID ATLANTIC COAST WILL HANG ON INTO
SATURDAY NIGHT. DRY CONDITIONS WILL LINGER. THERE IS A CHANCE FOR
A FEW UPSLOPE SNOW SHOWERS IN THE HIGHER PARTS OF THE POTOMAC
HIGHLANDS. JUST TWENTY FOUR HOURS AGO...THE EURO AND GFS MODELS
WERE BOTH HINTING OF A COLD FRONTAL PASSAGE SATURDAY INTO SATURDAY
NIGHT. SINCE THEN...BOTH MODELS HAVE BACKED OFF ON THIS IDEA.
THE COLD FRONT SHOULD PUSH ACROSS THE AREA SUNDAY BEFORE SLIDING TO
THE SOUTH AND STALLING ACROSS THE CAROLINAS BY SUNDAY NIGHT. SOME
LIGHT STRATIFORM RAIN WILL ACCOMPANY THE FRONT SUNDAY AND INTO
MONDAY WITH THE FRONT JUST TO OUR SOUTH. THE 00Z EURO MODEL STILLS
WANTS TO HANG ONTO THE IDEA OF A LOW DEVELOPING ALONG THE STALLED
FRONT BUT NOW THE GFS JUST WANTS TO PUSH ELONGATED STRANDS OF ENERGY
ALONG THE SURFACE FRONT AND OUT TO SEA. CONSIDER THIS...HIGH
UNCERTAINTY ON WHETHER WE SEE ADDITIONAL PERIODS OF LIGHT RAIN OR
PERHAPS LIGHT SNOW IN OUR CWA BY MONDAY NIGHT.
THERE IS A SLIGHT CHANCE OF SOME DEPARTING RAIN OR SNOW SHOWERS
TUESDAY...SHOULD A LOW DEVELOP ALONG THE FRONT. OTHERWISE...DRY
CONDITIONS WILL BE BROUGHT ABOUT WITH HIGH PRESSURE BUILDING LATER
TUESDAY THROUGH WEDNESDAY.
&&
.AVIATION /03Z THURSDAY THROUGH MONDAY/...
IFR OR LOWER CONDITIONS THIS EVENING AHEAD OF APPROACHING FRONT.
LIFR CIGS ACROSS THE AREA THRU AT LEAST 05Z. CURRENTLY HAVE CIGS
IMPROVING TO IFR OR MVFR AS THE FRONT/SHOWERS MOVE THRU.
HOWEVER...IMPROVEMENT TIME COULD BE 2-3 HOURS LATER THAN IN TAF.
NOT EXPECTING VFR TILL LATE TONIGHT. LOW CONFIDENCE ON TIMING OF CIGS.
VIS VARYING FROM LESS THAN 1 MILE TO 3 MILES ACROSS THE TAF
SITES. WILL KEEP VIS DOWN THROUGH THE NIGHT TILL FROPA...IMPROVING
TO P6SM LATE TONIGHT. THE 1 MILE OR LESS COULD CONTINUE 1-2 HOURS
LATER THAN IN TAF.
HIGHEST CONFIDENCE IN FORECAST IS WINDS...SLY FLOW THIS
EVENING...BCMG SW THEN W OVERNIGHT WITH FROPA. PSBL OCNL GUSTS
WITH W FLOW LATE TONIGHT...THEN MORE PERSISTENT GUSTS 20-25 KTS
DURING THE DAY TOMORROW. VFR CONDITIONS AS WELL THRU THE DAY WITH
SCT CU.
HIGH PRESSURE BUILDS IN AS THE POTENT LOW PRESSURE SYSTEM MOVES OFF
THE COAST LATE THU. THE HIGH WILL KEEP CONDITIONS QUIET/SOLID VFR
INTO THE WEEKEND.
&&
.MARINE...
WINDS SLOW TO INCREASE THIS EVENING ON THE WATERS WITH QUITE A
STABLE AIRMASS IN PLACE. OCNL GUSTS TO 17-18 KTS MAINLY OVER THE
SOUTHERN WATERS...BUT OTHERWISE...NOT QUITE AT SCA YET.
HOWEVER...EXPECTING A STRONG LLJ TO MOVE OVER THE WATERS THROUGH
THE OVERNIGHT...WHICH COULD SEE ENOUGH ENERGY MIX DOWN TO RESULT
IN GUSTS TO 20 KTS. HIGHER CONFIDENCE OF SCA EXISTS THOUGH IN THE
WAKE OF THE COLD FRONT THURS.
CDFNT E OF WATERS BY THU. WHILE GLW CONDS NOT OUT OF THE QSTN...IT
WUD TAKE IDEAL MIXING. STICKING W/ MEAN MIXED LYR...AND CARRYING SCA
THRU THE DAY.
LIGHT WINDS TO CLOSE OUT THE WEEK AS A LARGE SFC HIGH DEVELOPS TO
OUR SOUTH AND CALMS DOWN THE AREA WIND FIELD. SLY CHANNELING
POSSIBLE INTO LATE SAT W/ THE HIGH MOVING OFF THE COAST AND ANOTHER
LOW PRESSURE SYSTEM APPROACHING FROM THE WEST.
&&
.TIDES/COASTAL FLOODING...
TIME OF HIGH TIDE HAS PASSED FOR LOWER CHESAPEAKER BAY WITH WATER
LEVELS SLOWLY COMING DOWN NOW. AS OF 7 PM...LEVELS BELOW ANY
FLOODING THRESHOLDS SO ALLOWED THE ADV TO EXPIRE THERE. CONTINUING
NORTHERN CHESAPEAKE BAY WESTERN SHORE AS ANNAPOLIS CURRENTLY
SHOWING IN SOLID MINOR LVLS...AND THE REMAINING AREAS EXPECTING TO
REACH MINOR LVLS WITH 1.5 FT ANOM PSBL.
A COLD FRONT CROSSES THE WATER TONIGHT. DIRECTION NOT ALL THAT
GREAT FOR BLOWOUT CONDITIONS. WE WILL NEED TO SEE HOW MUCH WATER
IS TRULY PUSHED OUT. MAY NEED AN ADVISORY FOR ANOTHR CYCLE...ESPECIALLY
MID BAY. ON THE FLIP SIDE...THE AM CYCLE IS THE LOWER OF THE TWO
ASTRONOMICALLY.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...WIND ADVISORY UNTIL 6 AM EST THURSDAY FOR MDZ501.
COASTAL FLOOD ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR MDZ011-
014-508.
VA...WIND ADVISORY UNTIL 6 AM EST THURSDAY FOR VAZ503-504.
WV...WIND ADVISORY UNTIL 6 AM EST THURSDAY FOR WVZ501>503-505-506.
MARINE...SMALL CRAFT ADVISORY UNTIL 5 PM EST THURSDAY FOR ANZ530>543.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON MS
911 PM CST FRI DEC 26 2014
.UPDATE...
THE PRECIP HAS PRETTY MUCH CEASED IN OUR AREA FOR NOW. MOISTURE WILL
CONTINUE TO BUILD INTO THE AREA OVERNIGHT THOUGH AND ISENTROPIC
ASCENT WILL INCREASE. LOOKING AT SOME OF THE HI-RES MODELS...THE ARW
AND HRRR SPECIFICALLY...A LULL IS INDICATED IN THE HOURS BETWEEN 00Z
AND 09Z. THIS SEEMS TO BE THE PRESENT CASE SO THEREFORE IT HAS BEEN
REFLECTED IN OUR POPS GRIDS. PRECIP WILL GRADUALLY BUILD BACK INTO
OUR AREA FROM THE SOUTHWEST BEFORE 12Z. THE HOURLY TEMPS AND DEWPOINTS
WERE ADJUSTED FOR THIS UPDATE. OTHERWISE...THE GOING FORECAST SEEMS
TO BE PRETTY GOOD. /10/
&&
.AVIATION...
INTERMITTENT LIGHT RAIN WL CONT TO SPREAD ACROSS THE AREA FROM THE
SW AND BRING BRIEF VSBY RESTRICTIONS BUT VFR CONDITIONS WL PREVAIL AT
MOST TAF SITES THROUGH 12Z SAT. THE EXCEPTION WL BE GLH WHERE IFR
CIGS ARE EXPECTED BEFORE 12Z SAT. CIGS WL LOWER TO IFR CONDS ALONG
WITH REDUCED VSBYS SAT MORNING AS WIDESPREAD RAIN DEVELOPS OVER THE
AREA. ISOLD TSTMS WL BE PSBL LATE SAT AFTN SE. IFR/LIFR CONDS WL
PREVAIL SATURDAY NIGHT THROUGH SUNDAY MORNING. /22/
&&
.PREV DISCUSSION... /ISSUED 413 PM CST FRI DEC 26 2014/
SHORT TERM...
..FRIDAY NIGHT THROUGH MONDAY MORNING...
RAINFALL IS SLOWLY INCREASING THIS AFTERNOON AND WILL CONTINUE
THROUGH THE AFTERNOON AND ESPECIALLY INTO TONIGHT. CLOUDS WILL
CONTINUE TO INCREASE FROM THE W AS ISENTROPIC LIFT/MOISTURE
TRANSPORT SLOWLY INCREASES FROM THE W/SW. CLOUDS WILL FILL IN
TONIGHT ACROSS THE AREA...KEEPING LOWS IN THE MID 50S IN THE W TO
WHILE SLOWER MOVEMENT INTO THE E LOWS WILL DROP INTO THE UPPER 40S.
AS THE SFC COLD FRONT SLOWLY PROGRESSES SE THROUGH THE CENTRAL PLAINS
AND 80-100KT+ H3 JET/UPPER DIFFLUENCE AID IN INCREASING LIFT...EXPECT
INCREASING MOISTURE TRANSPORT BEGINNING TONIGHT IN OUR THE REGION.
EURO/GFS ARE IN GOOD AGREEMENT THAT ANOMALOUS PW`S...SOME 2-3
STANDARD DEVIATIONS ABOVE NORMAL AND THE 99TH PERCENTILE....WILL
BEGIN TO MOVE INTO THE REGION BEGINNING LATE TONIGHT. THE LONGWAVE
TROUGH OVER THE ROCKIES/NRN PLAINS WILL ONLY SLOWLY MOVE E DUE TO THE
BLOCKING OF THE 590+DM H5 RIDGE OVER SW ATLANTIC. THIS SETUP WILL PUT
THE REGION IN A FAVORABLE SYNOPTIC PATTERN FOR HEAVY RAIN AND SOME
LOCALIZED FLASH FLOODING ...BETWEEN DEEP LONGWAVE TROUGH/SW FLOW
ALOFT/STRONG SE UPPER RIDGE. AS THE SFC LOW PRESSURE SLOWLY DEVELOPS
ALONG THE GULF COAST...MOVES TO THE NE AND THE COLD FRONT SLOWLY
MOVES INTO THE AREA LATE THIS WEEKEND...HEAVY RAIN WILL CONTINUE
SATURDAY AND INTO SUNDAY NIGHT. MODELS CONTINUE TO INDICATE THAT
THERE COULD BE SOME RAINFALL TOTALS BETWEEN 2-4 INCHES. 18Z NAM/HI-
RES ARW/NMM ARE INDICATING EVEN HIGHER AMOUNTS WITH SOME IN EXCESS OF
4-5 INCHES AND SHIFTED SLIGHTLY N TOWARDS THE JACKSON METRO AREA. IN
AREAS WHERE CONVECTIVE DEVELOPMENT CAN OCCUR...WHICH IS POSSIBLE DUE
TO ELEVATED INSTABILITY/MAUL ENVIRONMENTS...THIS IS NOT OUT OF
QUESTION. MAIN AREA OF CONCERN LOOKS TO REMAIN ALONG/SE OF THE
NATCHEZ TRACE CORRIDOR WHERE THE BEST MOISTURE TRANSPORT/ISENTROPIC
LIFT WILL RESIDE. RAIN WILL CONTINUE THROUGH THE WEEKEND WHILE THE
HEAVIEST LOOKS TO MOVE INTO OUR AREA BETWEEN 18-00Z SUNDAY. EXPECT
RAINFALL TO MOVE OUT OF THE AREA EARLY MONDAY MORNING AS THE COLD
FRONT MOVES THROUGH. LATER SHIFTS WILL MONITOR THE POTENTIAL FOR
FLASH FLOOD WATCH IF GLOBAL/HI-RES GUIDANCE CONTINUE TO INDICATE
POTENTIAL FOR EVEN HIGHER AMOUNTS. HWO/GRAPHICS ARE OUT HIGHLIGHTING
THE LIMITED HEAVY RAIN POTENTIAL.
ALSO OF RELEVANCE IS THE LIMITED POTENTIAL FOR SOME SEVERE WEATHER
IN THE HWY 84 CORRIDOR BOTH SATURDAY AND SUNDAY. MAIN AREA FOR
SATURDAY WILL BE IN NE LA/SW MS WHILE SHIFTING INTO THE SE PORTIONS
OF THE AREA SUNDAY. DEWPOINTS IN THE LOWER 60S AND BETTER LAPSE
RATES/SOME POTENTIAL SFC INSTABILITY WILL RESIDE WITH EFFICIENT
0-1KM AND 0-3KM BULK SHEAR APPROACHING 25-35KTS OR SLIGHTLY HIGHER.
THIS WILL DEPEND ON THE EVENTUAL TRACK OF THE LOW ON WHERE THE MOST
EFFICIENT WIND PROFILES WILL RESIDE BUT THIS AREA IN NE LA/SRN MS
CONTINUES TO REMAIN FAVORABLE. INSTABILITY WILL BE LOWER THAN
EARLIER THIS WEEK AND THUS ONLY A LIMITED CHANCE EXISTS FOR SEVERE
WEATHER THIS WEEKEND. HWO/GRAPHICS ARE OUT HIGHLIGHTING THE SEVERE
POTENTIAL.
AS THE UPPER RIDGE WEAKENS...THE LOW PRESSURE WILL MOVE TO THE NE
LATE SUNDAY NIGHT AND INTO MONDAY AND THE UPPER TROUGH WILL
GRADUALLY SWING THROUGH...BRINGING THE COLD FRONT THROUGH THE
REGION. TEMPERATURES WILL FALL INTO THE UPPER 30S IN THE NW DELTA
WHILE ONLY IN THE 50S IN THE SE. FOR FORECAST ELEMENTS...WENT WARMER
TONIGHT IN W/SW DUE TO CLOUDS/PRECIP MOVING IN. WENT SLIGHTLY COOLER
SATURDAY NEAR EURO DUE TO RAIN/OVERCAST CONDITIONS. WENT CLOSER TO
RAW GUIDANCE SATURDAY AND INTO MONDAY AS GUIDANCE WILL HANDLE THE
TEMPS WITH THE FRONTAL PASSAGE BETTER THAN MOS. RELEVANT PORTION OF
THE PREVIOUS LONG TERM DISCUSSION IS ATTACHED. /DC/
LONG TERM...
..MONDAY INTO LATE NEXT WEEK...
EXPECT COOLER AND DRIER WEATHER BEHIND THE FRONT FOR THE MON NIGHT
THROUGH TUES NIGHT PERIOD WITH TEMPERATURES GENERALLY NEAR SEASONAL
AVERAGES. AS WE GO INTO MID WEEK...MODELS ARE IN GENERAL AGREEMENT
THAT A MASSIVE ARCTIC AIRMASS WILL SURGE SOUTHWARD THROUGH THE
PLAINS AND EXPAND INTO THE LOWER MS VALLEY REGION NEW YEAR`S EVE.
THE LARGEST TEMPERATURE ANOMALIES ARE EXPECTED TO STAY WEST OF THE
ARKLAMISS BASED ON THE PRESSURE PATTERN...BUT IT WILL BE SUCH A
STRONG HIGH PRESSURE CENTER THAT SUFFICIENTLY COLD AIR FOR WINTER
WEATHER POTENTIAL MAY EXIST INTO NORTHERN PORTIONS OF THE AREA AS
SOUTHWEST FLOW JUXTAPOSES THE SHALLOW MODIFYING ARCTIC AIR.
ALTHOUGH GFS/ECMWF ARE BEARISH WITH QPF FOR MID/LATE WEEK...THE
AIRMASS OVER THE GULF WILL CONTINUE TO BE UNSEASONABLY MOIST AND
PRIME FOR QUICK NORTHWARD TRANSPORT WITH THE SLIGHTEST DISTURBANCE
AND BACKING OF LOW LEVEL FLOW GIVEN THE STRONG GULF COAST BAROCLINIC
ZONE. GUIDANCE IS SLIGHTLY SLOWER ON MOISTURE RETURN ON NEW YEARS EVE
AND ONLY INCLUDED MENTION OF RAIN FOR NOW. HOWEVER...THERE EXISTS A
POSSIBILITY SOME OF THAT MOISTURE COULD MOVE FURTHER N OVER TOP THE
SHALLOW ARCTIC AIRMASS...WHICH COULD BRING THE CHANCE FOR WINTRY
PRECIP. WE WILL CLOSELY MONITOR THAT POSSIBILITY. IT DOES NOT APPEAR
THE ARKLAMISS WILL EXPERIENCE OVERLY COLD TEMPERATURES GIVEN THE
TREND FOR INCREASING SOUTHERN STREAM SEPARATION/DOMINANCE AND NRN
STREAM RETREAT. /EC/DC/
&&
HYDROLOGY...WILL CONTINUE MENTION OF 2-4 INCHES OF RAIN ACROSS THE
SOUTHEASTERN PORTION OF OUR FORECAST AREA IN OUR GRAPHICS AND THE
HAZARDOUS WEATHER OUTLOOK. THIS RAIN MAY HAVE SOME IMPACT SINCE IT
FOLLOWS SO CLOSELY BEHIND THE HEAVY RAIN THAT FELL IN THAT REGION ON
TUESDAY. RAINFALL RATES WILL BE CRITICAL AS TO WHETHER THIS BECOMES
A FLASH FLOODING EVENT OR JUST A SOAKING RAIN.
CONTINGENCY FORECASTS COMPLETED BY THE LOWER MISSISSIPPI RIVER
FORECAST CENTER FOR AREA RIVERS INDICATE THAT EVEN WITH THIS HEAVY
RAINFALL...RIVERS SHOULD REMAIN MOSTLY BELOW FLOOD STAGE. IF THE
RAIN IS A BIT HEAVIER THAN EXPECTED...A FEW RIVER POINTS MAY REACH
INTO THE MINOR FLOOD CATEGORY. OVERALL RIVER IMPACT IS EXPECTED TO
BE LOW.
HAVE ISSUED A HYDROLOGIC OUTLOOK AS A PREVIEW FOR A POTENTIAL FLOOD
WATCH. /SW/
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 53 63 59 60 / 55 100 94 89
MERIDIAN 48 59 56 65 / 32 100 95 81
VICKSBURG 55 66 53 54 / 65 100 92 85
HATTIESBURG 53 63 63 70 / 45 100 95 70
NATCHEZ 57 67 56 57 / 65 100 94 83
GREENVILLE 53 63 46 50 / 61 100 89 61
GREENWOOD 53 61 50 52 / 42 100 92 73
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1001 PM CST Fri Dec 26 2014
.UPDATE...
Issued at 958 PM CST FRI DEC 26 2014
Adjusted overnight PoPs for radar trends and added drizzle (did that
awhile back). Have also pulled Pops westward into the southwestern
CWA Saturday morning to account for latest HRRR trend towards
developing a secondary area of light precipitation northeastward into
east central KS/west central MO. Satellite imagery shows rapid
increase in upstream mid clouds from southeast NM through western OK.
Some question as to whether or not the 00z NAM`s dry wedge under this
cloud layer is real or not. 00z OKC sounding suggests otherwise. 12z
ECMWF supports the HRRR solution while the 00z GFS does pick up on
some QPF Sat morning making it into our southeastern CWA.
Precipitation type dependent on near surface temperatures and
vertical stratification of same. Tricky. Fortunately QPF should be
minor.
&&
.DISCUSSION...
Issued at 307 PM CST FRI DEC 26 2014
Cold front has reached the KC area this afternoon, though its
southward progress has slowed with a weak surface wave moving
up from the south. This feature is starting to produce some light
showers across west central Missouri, and light precip should
continue to blossom through the late afternoon and evening as low
pressure rides up the boundary. Precip amounts will be light,
generally less than a tenth of an inch, and mostly confined to areas
near and southeast of the I-35 corridor. Temperatures should remain
above freezing across these areas so no wintry precipitation is
expected.
Behind the front, a second area of precipitation developing over
central KS will spread into eastern Nebraska and northern Iowa
overnight where several inches of snow will accumulate, but most of
this snowfall now looks like it will miss our forecast area almost
entirely to the north. While far northwest Missouri may still see
some light snow later this evening, possibly even a bit of sleet, any
accumulations should be very minor and may not accumulate at all with
relatively warm ground temperatures.
Airmass behind the front will be seasonably chilly with highs in the
30s and lows in the teens/20s over the weekend. A stronger front will
swing through the region on Monday and looks to bring some of the
coldest air of the season so far. Highs Tuesday and Wednesday are
forecast to be in the 20s...maybe even teens for some areas...while
lows drop into the single digits. Wind chills could be between zero
and 10 below. Other than perhaps some very light snow accompanying
Monday`s front, the forecast through the middle of next week looks
dry. The pattern then looks to get active by late next week with both
GFS and ECMWF taking a closed upper low out of the Southwest and into
the Plains/Midwest by Friday/Saturday. Will be interesting to watch how
future model runs play out, but given the inherent low-predictability
with such a system, several swings in track and intensity are highly
likely and we are still days away from knowing any details, or even
if such a system will impact our region at all.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday Evening)
Issued at 543 PM CST FRI DEC 26 2014
Cold front currently extends along a general line from KIRK to KCNU and
continues to slowly move southward. Drizzle has developed along and
south of the front. Ceilings have continued to bounce between MVFR
and VFR but are expected to drop back to MVFR then to IFR by 02-03Z
as lower ceilings and reduced visibility move in behind the front.
Short term models are developing a band of light rain showers to
develop between a 03-07Z time frame. IFR deck will scatter out
tomorrow morning with MVFR deck beginning to scatter out by tomorrow
afternoon.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
UPDATE...MJ
DISCUSSION...Hawblitzel
AVIATION...PMM
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
513 PM CST Fri Dec 26 2014
.SHORT TERM: (Through Sunday Night)
Issued at 329 PM CST Fri Dec 26 2014
Low pressure will develop along the cold front currently over
northwest Missouri in response to shortwave trough ejecting out of
the base of mean trough over the western CONUS tonight. This low
will move northeast into the Great Lakes by tomorrow at the same
time that the shortwave moves into the the Upper Midwest. NAM and
GFS show that the cold front will enter the northwest part of the
CWA late tonight and exit the CWA by tomorrow afternoon. While
precipitation is currently limited on radar over the central CONUS,
expect rain chances to increase rapidly this evening as low level
moisture convergence increases ahead of shortwave trough. Latest
runs of the HRRR as well as the NSSL-WRF have depicted rain
developing throughout the evening hours with it becoming more
concentrated over southeast Missouri into southern Illinois after
midnight. Have continued going forecast trend of increasing
chance PoPs through the evening hours and with likely PoPs over
the southeast half of the CWA after midnight. Then concentrated
likely PoPs tomorrow morning over the southeast half of the CWA
when the GFS depicts increasing mid level frontogenesis associated
with the shortwave trough. Kept a chance of rain or snow going
over the far southeast part of the CWA tomorrow evening before
drier air and subsidence works into the area on Saturday evening.
Sunday and Sunday evening still looks dry at this point.
Kept with falling temperatures will frontal passage tomorrow.
Otherwise MOS guidance are in decent agreement and looks
reasonable.
Britt
.LONG TERM: (Monday through Next Friday)
Issued at 329 PM CST Fri Dec 26 2014
There is relatively good agreement in the global models in that a
positively tilted mean trough will stay established through at
least the first half of next week from central Canada into the
western CONUS. This will keep a relatively fast zonal flow over
MO/IL through most of the period. A large area of surface high
pressure will move under the zonal flow with no real notable
shortwaves troughs that would offer any precipitation chances at
least through Thursday. Model discrepancies show up by Friday as
the operational GFS is faster than it`s own ensemble mean in
ejecting the main upper low out of the southwest toward the
Midwest. While this is faster than the rest of the models, even
the ECMWF is showing precipitation developing over the area in a
broad warm air advection regime ahead of it bringing the upper low
through the area on Saturday. So with this said will go ahead and
introduce snow with some rain to the forecast on Friday.
Cold front will pass through the area on Monday and temperatures
will fall below normal on Tuesday and Wednesday before returning to
near normal for the start of a new year late in the week.
Britt
&&
.AVIATION: (For the 00z TAFs through 00z Saturday Evening)
Issued at 500 PM CST Fri Dec 26 2014
Wave development along a cold front across far western Missouri
has slowed its eastward movement, so think MVFR cigs will be
delayed for several hours, reaching KCOU around 06Z and KSTL
around 09Z. There may be a few scattered very light showers or
sprinkles before the surface cold front passes. The front will reach
KCOU around 12Z and KSTL by 16Z. MVFR ceilings will continue for
several hours after frontal passage, but MVFR ceilings will
gradually lift to VFR during the afternoon.
Specifics for KSTL: VFR cigs will continue through at least 06Z,
with MVFR cigs reaching KSTL around 09Z. There may be a few
scattered very light showers or sprinkles before the surface cold
front passes. The front will reach KSTL by 16Z. MVFR ceilings
will continue for several hours after frontal passage, but MVFR
ceilings will gradually lift to VFR during the afternoon. MVFR
cigs should last well into Saturday evening.
Browning (WFO LSX)/MAB (EAX CWSU)
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1133 PM CST Wed Dec 24 2014
.UPDATE:
Issued at 831 PM CST Wed Dec 24 2014
Already updated the fcst once this evng to account for the
lingering precip across the area and it looks like another update
will be necessary as the pesky light rain and drizzle will be slow
to exit the area. The precip has slowly been transitioning from
measurable to trace over the past several hrs. So that will be
the flavor thru midnight...lingering patchy drizzle. Temps have
also been slow to fall off and have been holding steady so far
this evng despite the CAA. Still think lows for tonight look good
with upstream obs across wrn MO in the low 30s. All other elements
look reasonable with only minor adjustments to account for short
term trends. A new update will be out shortly.
2%
&&
.SHORT TERM: (Through Tonight)
Issued at 325 PM CST Wed Dec 24 2014
An area of light rain possibly mixed with a few wet snowflakes
currently centered through St. Louis was moving east around 25-30
kts. This precipitation is occurring in association with a trailing
vort max within the cyclonic flow on the backside of the exiting
upper trof. Present indications are it should have exited or just
about exited the eastern CWA counties in south central/southwest IL
at 00z. There might be some lingering patchy drizzle for a few hours
into early evening. Satellite imagery has stratus hanging tough and
still well back into eastern KS and eastern OK at 21z. Trends along
with the RAP and NAM 925 mb RH suggests the clearing trend will be
slow and won`t commence in our CWA until well after midnight, and
the back edge of clouds around 50 miles west of STL at 12z Thursday.
The clouds will help keep temperatures a tad warmer overnight than
the previous forecast.
Glass
.LONG TERM: (Thursday through Next Wednesday)
Issued at 325 PM CST Wed Dec 24 2014
(Thursday through Saturday)
Primary focus thru this period will be precip chances late in the
period.
Mdls remain in good agreement thru Fri. Sfc winds quickly become sly
by tomorrow as ridge quickly moves off to the E. Expect current
cloud deck to move ewd tonight and shud be along/near the MS River
around 12z Thurs. These clouds shud be on the ern boarder of the CWA
by 18z. However, mdls suggest these low clouds will probably be
replaced with CI which shud hinder heating somewhat. Have therefore
kept temps twd the cooler guidance, esp across ern portions of the
CWA will clouds will linger. For Fri, have trended slightly warmer
as strong sly winds will be in place. However, with questions
regarding cloud cover, did not go as high as warmer MOS for now.
Cut off low over srn Rockies begins to open and eject into the
Plains by Fri evening. However, the GEM is a slower soln and
actually redevelops an upper low after the initial s/w is reaching
the nrn Plains. As this soln is an outlier, have trended away from
this soln and twd the other mdls which remain in good agreement.
Have kept PoPs in lower chance category for now as mdl soundings
suggest much of the QPF may be more DZ than RA. Not to mention that
the NAM and local WRF suggest the precip bifurcating with a branch
to the N and one to the S. However, with the trof approaching and
some low level forcing, light RA will be possible. Question becomes
p-types on Sat and Sat night as the cold air filters into the
region. While the GFS soundings suggest precip will end as a brief
period of IP, then SN, setup is typical of this area where precip
will likely end as RA just ahead of the surge of cold air. This is
more likely given the sfc ridge center is currently progd to be over
wrn KS. Regardless, close attention shud be paid to this time period
as mdls come into better agreement.
(Sunday through Wednesday)
Focus quickly turns to temps thru this period.
Will continue trends twd a GFS/ECMWF compromise due to issues with
the GEM mentioned above. The DGEX also becomes a fast outlier as the
next trof ejects into the Plains sometime on Wed.
Relatively cold air moves in place behind the cdfnt on Sat. A
secondary cdfnt is expected to push thru the region Sun night into
Mon ahead of the next system approaching the region late Mon night
into Wed. Have trended temps twd cooler guidance for Tues and beyond
placing temps nearly 20 degrees below seasonal avg.
A number of questions arise with the system on Tues/Wed. The GFS
cuts off an upper low over the swrn U.S. which it is known to do.
The ECMWF ejects this trof into the Plains, but given the weakening
jet upstream of this trof, am not convinced this soln is correct.
With both mdls suggesting very low QPF, will keep only slight chance
PoPs going for now with plenty of time to adjust. The one item both
mdls do agree on is the precip is expected to be all SN.
Tilly
&&
.AVIATION: (For the 06z TAFs through 06z Thursday Night)
Issued at 1132 PM CST Wed Dec 24 2014
Back edge of SC deck is making its way east across western MO as
of 0530z. KCOU should begin to scatter out around 08z Thursday,
while KUIN and metro area tafs should scatter out between 11z-12z
Thursday. Otherwise, west winds to back to the south by daybreak
and pickup by mid morning to between 10 and 15kts and remain that
way through rest of forecast period.
Specifics for KSTL:
Back edge of SC deck is making its way east across western MO as
of 0530z. Metro area should scatter out between 11z-12z Thursday.
Otherwise, west winds to back to the south by 12z and pickup
by 18z to between 10 and 15kts and remain that way through
rest of forecast period.
Byrd
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED
NWS BILLINGS MT
1108 AM MST THU DEC 25 2014
.UPDATE...
SNOW CONTINUES TO WIND DOWN FROM NORTH TO SOUTH. ENDED ADVISORIES
FOR YELLOWSTONE AND NORTHERN BIG HORN COUNTIES. TWH
&&
.SHORT TERM...VALID FOR TDY AND FRI...
SNOW WILL CONTINUE IN EARNEST IN MANY AREAS THIS MORNING...BUT THE
PRECIPITATION WILL END FROM NORTH TO SOUTH DURING THE DAY.
AS OF 10 UTC /3 AM MST/...SNOWFALL CONTINUES OVER SOUTH CENTRAL MT
AND HAS BEEN INTENSIFYING OVER NORTH CENTRAL WY IN THE LAST COUPLE
OF HOURS. ONE TO THREE INCHES OF SNOW HAS BEEN COMMON SO FAR WHICH
IS IN LINE WITH FORECAST EXPECTATIONS...WITH SNOW-TO-LIQUID RATIOS
LIMITED SOMEWHAT BY A LACK OF STRONGER VERTICAL MOTION WITHIN THAT
FAVORABLE -12 TO -18 C DENDRITIC GROWTH ZONE. HOWEVER...THE GROUND
IS ALSO WARM AND THAT HAS BEEN REDUCING SNOW ACCUMULATION TOO WITH
A SLUSHY BASE UNDERNEATH THE SNOW OBSERVED HERE IN BILLINGS. THERE
WAS A DROP-OFF IN SNOWFALL AROUND MILES CITY EARLY IN THE NIGHT AS
FRONTOGENETICAL FORCING SAGGED SOUTHWARD AND AS OF THIS HOUR RADAR
TRENDS SUGGEST A SIMILAR SCENARIO IS TAKING PLACE FURTHER WESTWARD
INTO MUSSELSHELL...GOLDEN VALLEY AND WHEATLAND COUNTIES TOO. BASED
ON THOSE RADAR TRENDS AND THE CONSENSUS OF SHORT-TERM MODEL OUTPUT
WE DECIDED TO DROP THAT NORTHERN STRIP OF COUNTIES FROM THE WINTER
WEATHER ADVISORY WITH THIS FORECAST PACKAGE AS ADDITIONAL SNOWFALL
AFTER 12 UTC WILL BE UNDER AN INCH FROM HARLOWTON EASTWARD TO RYE-
GATE...ROUNDUP AND MILES CITY.
THE AREA OF COLDER CLOUD TOPS WHICH EARLIER COINCIDED WITH HEAVIER
SNOW AT BOZEMAN ARE LIKELY INDICATIVE OF THE STRONGER BATCH OF 500
TO 300 MB Q-VECTOR CONVERGENCE THAT GUIDANCE CONTINUES TO SHIFT TO
THE EAST-SOUTHEAST ALONG A LINE FROM LIVINGSTON TO SHERIDAN DURING
THE MORNING. THE SAME SHORT-TERM MODEL GUIDANCE THAT WAS MENTIONED
EARLIER...INCLUDING RECENT HRRR SIMULATIONS...PICKS UP ON THAT AND
WE WERE ABLE TO FOLLOW IT FOR THE SNOWFALL FORECAST IN THOSE AREAS
TOO. THAT MEANS WE ARE STILL BANKING ON ABOUT 2 MORE INCHES BEYOND
12 UTC FROM LIVINGSTON TO BILLINGS AND 4 TO 6 INCHES FOR THE FOOT-
HILLS LIKE AT RED LODGE AND SHERIDAN. SNOW-TO-LIQUID RATIOS SHOULD
CLIMB FROM THEIR OVERNIGHT AVERAGE AROUND 10 TO 1 INTO THE 15 TO 1
RANGE THIS MORNING BASED ON BUFKIT SNOW GROWTH VISUALIZATIONS...SO
THAT SHOULD HELP OUT ACCUMULATIONS. FORECAST-WISE...THIS WAS WELL-
HANDLED PREVIOUSLY...AND THE MAIN CHANGES WE MADE WERE TO DROP OFF
THE SNOW CHANCE MUCH MORE QUICKLY FROM NORTH TO SOUTH BEGINNING AT
18 UTC. FORECAST SOUNDINGS SHOW THE SATURATED LAYER SHRINKS RATHER
QUICKLY AND SO BY AFTERNOON PLACES LIKE BILLINGS COULD HAVE ONLY A
FEW FLURRIES LEFT. THUS...LATER FORECAST UPDATES SHOULD BE ABLE TO
DROP MORE OF THE REMAINING WINTER WEATHER ADVISORY EARLY.
BY TONIGHT...THE WEATHER WILL HAVE QUIETED DOWN CONSIDERABLY...BUT
WE MIGHT HAVE TO CONSIDER ADDING SOME FOG TO THE FORECAST IN LATER
RELEASES. THE 00 UTC NAM-BASED MOS /MET GUIDANCE/ SUPPORTED FOG IN
MANY PLACES INCLUDING BILLINGS...BUT THAT LACKS SUPPORT WITHIN THE
OTHER MODEL GUIDANCE AND SO CONFIDENCE WASN/T HIGH ENOUGH TO PUT A
MENTION OF FOG IN THE FORECAST. IT WILL BE A COLD NIGHT WITH FRESH
SNOW IN MANY AREAS...ESPECIALLY IF FOG DOES NOT DEVELOP.
ON FRIDAY...WE HAVE A LOW-END SNOW SHOWER CHANCE IN PLACE FOR PART
OF THE AREA AS A WEAK 500-MB SHORTWAVE TROUGH CROSSES THE AREA. IT
LOOKS LIKE WE WILL ONLY WARM INTO THE 20S F. SCHULTZ
.LONG TERM...VALID FOR SAT...SUN...MON...TUE...WED...
MAINLY DRY SATURDAY WITH SOME DOWNSLOPE COMPONENT TO THE PRESSURE
GRADIENT BUT NOT ENOUGH TO BRING WARMING GIVEN INFLUENCE OF SNOW
COVER. HEIGHTS SLOWLY FALLING IN THIS PERIOD IN ADVANCE OF A
SYSTEM SWINGING INTO THE PACIFIC NORTHWEST. THIS ENERGY BEGINS
SPREADING INTO THE AREA ON SUNDAY AND PHASES WITH THE ARRIVAL OF
AN ARCTIC COLD FRONT. LIFT WITH THIS SYSTEM WILL BE MORE RELATED
TO THE DEEPENING OF THE COLD AIRMASS WITH A LESS DYNAMIC SET UP
ALOFT. HOWEVER ITS A COLDER SYSTEM AND SNOWFALL RATIOS SHOULD BE
HIGHER. SNOWFALL AMOUNTS AROUND 4 INCHES SEEM REASONABLE FOR
LOWER ELEVATIONS BUT FOOTHILLS WILL SEE A FAVORABLE UPSLOPE
PATTERN SO HIGHER AMOUNTS COULD BE POSSIBLE.
WILL BE THE COLDEST AIRMASS OF DECEMBER AS A 1050MB HIGH SETTLES
IN SUNDAY NIGHT INTO MONDAY. THIS SHOULD YIELD SINGLE DIGIT HIGH
TEMPERATURES ON MONDAY WITH A CHANCE AT TEENS BELOW ZERO MONDAY
NIGHT. SNOW COULD LINGER INTO MONDAY MORNING BUT WILL END DURING
THE DAY.
TUESDAY SHOULD INITIATE A WARMING TREND AS THE HIGH DIGS SOUTH OF
THE REGION AND PATTERN SUPPORTS A DOWNSLOPE FLOW BUT AIRMASS WILL
STILL BE PRETTY COLD. BETTER TEMPERATURE RECOVERY CAN BE EXPECTED
WEDNESDAY BUT TEMPERATURES SHOULD STILL BE BELOW NORMAL. BORSUM
&&
.AVIATION...
SNOW WILL CONTINUE TO IMPACT SHERIDAN INTO THE AFTERNOON...WITH
SNOW COMING TO AN END AROUND BILLINGS AND LIVINGSTON BY LATE
MORNING. CEILINGS WILL REMAIN IFR TO MVFR UNTIL THE SNOW
ENDS...WITH CONDITIONS GENERALLY IMPROVING TO MVFR AFTER THE SNOW
MOVES OUT. MOUNTAIN OBSCURATIONS WILL CONTINUE THROUGH MUCH OF
THE DAY AND INTO THE EVENING. REIMER
&&
.PRELIMINARY POINT TEMP/POPS...
TDY FRI SAT SUN MON TUE WED
-------------------------------------------------------
BIL 028 006/025 009/026 016/021 904/006 914/008 903/027
5/S 21/B 11/B 25/J 52/J 21/B 11/N
LVM 028 901/026 002/027 014/024 908/011 915/016 003/030
9/S 51/B 12/J 45/J 42/J 21/B 11/N
HDN 028 004/025 003/026 014/023 904/007 915/009 907/025
5/S 22/J 11/B 25/J 52/J 22/J 11/N
MLS 027 011/024 011/027 017/021 000/008 905/010 002/025
2/S 12/J 11/B 14/J 42/J 11/B 11/B
4BQ 027 007/024 006/026 013/024 901/009 910/007 901/024
6/S 22/J 10/B 14/J 53/J 21/B 11/B
BHK 024 009/022 009/026 013/019 903/006 906/008 000/022
2/S 11/B 11/B 13/J 42/J 11/B 11/B
SHR 027 903/022 902/025 010/024 902/012 912/019 901/029
+/S 61/B 10/B 15/J 63/J 21/B 11/B
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...WINTER WEATHER ADVISORY IN EFFECT UNTIL 5 PM MST THIS
AFTERNOON FOR ZONES 34-36-37-39>41-58-64-65.
WINTER STORM WARNING IN EFFECT UNTIL 5 PM MST THIS AFTERNOON
FOR ZONES 38-56-66-67.
WY...WINTER WEATHER ADVISORY IN EFFECT UNTIL 5 PM MST THIS
AFTERNOON FOR ZONE 98.
WINTER STORM WARNING IN EFFECT UNTIL 5 PM MST THIS AFTERNOON
FOR ZONE 99.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION...UPDATED
NWS BILLINGS MT
921 AM MST THU DEC 25 2014
.UPDATE...
KBLX RADAR SHOWING SNOW WINDING DOWN OVER NORTHERN ZONES AS
COLDER AND DRIER AIR GRADUALLY WORKS IN. TAPERED SNOW OFF OVER THE
NORTH TO A FEW SNOW SHOWERS THE REST OF THE MORNING. SNOW WILL
CONTINUE FROM LIVINGSTON TO BILLINGS TO EKALAKA AND AREAS SOUTH
THROUGH THE MORNING. THE SNOW WILL TAPER OFF FROM NORTH TO SOUTH
INTO EARLY AFTERNOON WITH THE SNOW DECREASING TO A FEW SNOW
SHOWERS IN BILLINGS BY NOON. DROPPED THE ADVISORY FOR TREASURE
COUNTY AS ACCUMULATING SNOW HAS EFFECTIVELY STOPPED THERE. A
REPORT OF 10 INCHES WAS RECEIVED AT RED LODGE AS LOCATIONS SOUTH
OF BILLINGS WILL CONTINUE TO SEE ACCUMULATING SNOW INTO EARLY
AFTERNOON. WILL LEAVE THE REST OF THE HIGHLIGHTS IN PLACE.
TEMPERATURES WILL NOT MOVE MUCH TODAY WITH COLD AIR ADVECTION. TWH
&&
.SHORT TERM...VALID FOR TDY AND FRI...
SNOW WILL CONTINUE IN EARNEST IN MANY AREAS THIS MORNING...BUT THE
PRECIPITATION WILL END FROM NORTH TO SOUTH DURING THE DAY.
AS OF 10 UTC /3 AM MST/...SNOWFALL CONTINUES OVER SOUTH CENTRAL MT
AND HAS BEEN INTENSIFYING OVER NORTH CENTRAL WY IN THE LAST COUPLE
OF HOURS. ONE TO THREE INCHES OF SNOW HAS BEEN COMMON SO FAR WHICH
IS IN LINE WITH FORECAST EXPECTATIONS...WITH SNOW-TO-LIQUID RATIOS
LIMITED SOMEWHAT BY A LACK OF STRONGER VERTICAL MOTION WITHIN THAT
FAVORABLE -12 TO -18 C DENDRITIC GROWTH ZONE. HOWEVER...THE GROUND
IS ALSO WARM AND THAT HAS BEEN REDUCING SNOW ACCUMULATION TOO WITH
A SLUSHY BASE UNDERNEATH THE SNOW OBSERVED HERE IN BILLINGS. THERE
WAS A DROP-OFF IN SNOWFALL AROUND MILES CITY EARLY IN THE NIGHT AS
FRONTOGENETICAL FORCING SAGGED SOUTHWARD AND AS OF THIS HOUR RADAR
TRENDS SUGGEST A SIMILAR SCENARIO IS TAKING PLACE FURTHER WESTWARD
INTO MUSSELSHELL...GOLDEN VALLEY AND WHEATLAND COUNTIES TOO. BASED
ON THOSE RADAR TRENDS AND THE CONSENSUS OF SHORT-TERM MODEL OUTPUT
WE DECIDED TO DROP THAT NORTHERN STRIP OF COUNTIES FROM THE WINTER
WEATHER ADVISORY WITH THIS FORECAST PACKAGE AS ADDITIONAL SNOWFALL
AFTER 12 UTC WILL BE UNDER AN INCH FROM HARLOWTON EASTWARD TO RYE-
GATE...ROUNDUP AND MILES CITY.
THE AREA OF COLDER CLOUD TOPS WHICH EARLIER COINCIDED WITH HEAVIER
SNOW AT BOZEMAN ARE LIKELY INDICATIVE OF THE STRONGER BATCH OF 500
TO 300 MB Q-VECTOR CONVERGENCE THAT GUIDANCE CONTINUES TO SHIFT TO
THE EAST-SOUTHEAST ALONG A LINE FROM LIVINGSTON TO SHERIDAN DURING
THE MORNING. THE SAME SHORT-TERM MODEL GUIDANCE THAT WAS MENTIONED
EARLIER...INCLUDING RECENT HRRR SIMULATIONS...PICKS UP ON THAT AND
WE WERE ABLE TO FOLLOW IT FOR THE SNOWFALL FORECAST IN THOSE AREAS
TOO. THAT MEANS WE ARE STILL BANKING ON ABOUT 2 MORE INCHES BEYOND
12 UTC FROM LIVINGSTON TO BILLINGS AND 4 TO 6 INCHES FOR THE FOOT-
HILLS LIKE AT RED LODGE AND SHERIDAN. SNOW-TO-LIQUID RATIOS SHOULD
CLIMB FROM THEIR OVERNIGHT AVERAGE AROUND 10 TO 1 INTO THE 15 TO 1
RANGE THIS MORNING BASED ON BUFKIT SNOW GROWTH VISUALIZATIONS...SO
THAT SHOULD HELP OUT ACCUMULATIONS. FORECAST-WISE...THIS WAS WELL-
HANDLED PREVIOUSLY...AND THE MAIN CHANGES WE MADE WERE TO DROP OFF
THE SNOW CHANCE MUCH MORE QUICKLY FROM NORTH TO SOUTH BEGINNING AT
18 UTC. FORECAST SOUNDINGS SHOW THE SATURATED LAYER SHRINKS RATHER
QUICKLY AND SO BY AFTERNOON PLACES LIKE BILLINGS COULD HAVE ONLY A
FEW FLURRIES LEFT. THUS...LATER FORECAST UPDATES SHOULD BE ABLE TO
DROP MORE OF THE REMAINING WINTER WEATHER ADVISORY EARLY.
BY TONIGHT...THE WEATHER WILL HAVE QUIETED DOWN CONSIDERABLY...BUT
WE MIGHT HAVE TO CONSIDER ADDING SOME FOG TO THE FORECAST IN LATER
RELEASES. THE 00 UTC NAM-BASED MOS /MET GUIDANCE/ SUPPORTED FOG IN
MANY PLACES INCLUDING BILLINGS...BUT THAT LACKS SUPPORT WITHIN THE
OTHER MODEL GUIDANCE AND SO CONFIDENCE WASN/T HIGH ENOUGH TO PUT A
MENTION OF FOG IN THE FORECAST. IT WILL BE A COLD NIGHT WITH FRESH
SNOW IN MANY AREAS...ESPECIALLY IF FOG DOES NOT DEVELOP.
ON FRIDAY...WE HAVE A LOW-END SNOW SHOWER CHANCE IN PLACE FOR PART
OF THE AREA AS A WEAK 500-MB SHORTWAVE TROUGH CROSSES THE AREA. IT
LOOKS LIKE WE WILL ONLY WARM INTO THE 20S F. SCHULTZ
.LONG TERM...VALID FOR SAT...SUN...MON...TUE...WED...
MAINLY DRY SATURDAY WITH SOME DOWNSLOPE COMPONENT TO THE PRESSURE
GRADIENT BUT NOT ENOUGH TO BRING WARMING GIVEN INFLUENCE OF SNOW
COVER. HEIGHTS SLOWLY FALLING IN THIS PERIOD IN ADVANCE OF A
SYSTEM SWINGING INTO THE PACIFIC NORTHWEST. THIS ENERGY BEGINS
SPREADING INTO THE AREA ON SUNDAY AND PHASES WITH THE ARRIVAL OF
AN ARCTIC COLD FRONT. LIFT WITH THIS SYSTEM WILL BE MORE RELATED
TO THE DEEPENING OF THE COLD AIRMASS WITH A LESS DYNAMIC SET UP
ALOFT. HOWEVER ITS A COLDER SYSTEM AND SNOWFALL RATIOS SHOULD BE
HIGHER. SNOWFALL AMOUNTS AROUND 4 INCHES SEEM REASONABLE FOR
LOWER ELEVATIONS BUT FOOTHILLS WILL SEE A FAVORABLE UPSLOPE
PATTERN SO HIGHER AMOUNTS COULD BE POSSIBLE.
WILL BE THE COLDEST AIRMASS OF DECEMBER AS A 1050MB HIGH SETTLES
IN SUNDAY NIGHT INTO MONDAY. THIS SHOULD YIELD SINGLE DIGIT HIGH
TEMPERATURES ON MONDAY WITH A CHANCE AT TEENS BELOW ZERO MONDAY
NIGHT. SNOW COULD LINGER INTO MONDAY MORNING BUT WILL END DURING
THE DAY.
TUESDAY SHOULD INITIATE A WARMING TREND AS THE HIGH DIGS SOUTH OF
THE REGION AND PATTERN SUPPORTS A DOWNSLOPE FLOW BUT AIRMASS WILL
STILL BE PRETTY COLD. BETTER TEMPERATURE RECOVERY CAN BE EXPECTED
WEDNESDAY BUT TEMPERATURES SHOULD STILL BE BELOW NORMAL. BORSUM
&&
.AVIATION...
SNOW WILL CONTINUE TO IMPACT SHERIDAN INTO THE AFTERNOON...WITH
SNOW COMING TO AN END AROUND BILLINGS AND LIVINGSTON BY LATE
MORNING. CEILINGS WILL REMAIN IFR TO MVFR UNTIL THE SNOW
ENDS...WITH CONDITIONS GENERALLY IMPROVING TO MVFR AFTER THE SNOW
MOVES OUT. MOUNTAIN OBSCURATIONS WILL CONTINUE THROUGH MUCH OF
THE DAY AND INTO THE EVENING. REIMER
&&
.PRELIMINARY POINT TEMP/POPS...
TDY FRI SAT SUN MON TUE WED
-------------------------------------------------------
BIL 028 006/025 009/026 016/021 904/006 914/008 903/027
+/S 21/B 11/B 25/J 52/J 21/B 11/N
LVM 028 901/026 002/027 014/024 908/011 915/016 003/030
+/S 51/B 12/J 45/J 42/J 21/B 11/N
HDN 028 004/025 003/026 014/023 904/007 915/009 907/025
+/S 22/J 11/B 25/J 52/J 22/J 11/N
MLS 027 011/024 011/027 017/021 000/008 905/010 002/025
4/S 12/J 11/B 14/J 42/J 11/B 11/B
4BQ 027 007/024 006/026 013/024 901/009 910/007 901/024
+/S 22/J 10/B 14/J 53/J 21/B 11/B
BHK 024 009/022 009/026 013/019 903/006 906/008 000/022
3/S 11/B 11/B 13/J 42/J 11/B 11/B
SHR 027 903/022 902/025 010/024 902/012 912/019 901/029
+/S 61/B 10/B 15/J 63/J 21/B 11/B
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...WINTER WEATHER ADVISORY IN EFFECT UNTIL 5 PM MST THIS
AFTERNOON FOR ZONES 34>37-39>41-57-58-64-65.
WINTER STORM WARNING IN EFFECT UNTIL 5 PM MST THIS AFTERNOON
FOR ZONES 38-56-66-67.
WY...WINTER WEATHER ADVISORY IN EFFECT UNTIL 5 PM MST THIS
AFTERNOON FOR ZONE 98.
WINTER STORM WARNING IN EFFECT UNTIL 5 PM MST THIS AFTERNOON
FOR ZONE 99.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS BILLINGS MT
336 AM MST THU DEC 25 2014
.SHORT TERM...VALID FOR TDY AND FRI...
SNOW WILL CONTINUE IN EARNEST IN MANY AREAS THIS MORNING...BUT THE
PRECIPITATION WILL END FROM NORTH TO SOUTH DURING THE DAY.
AS OF 10 UTC /3 AM MST/...SNOWFALL CONTINUES OVER SOUTH CENTRAL MT
AND HAS BEEN INTENSIFYING OVER NORTH CENTRAL WY IN THE LAST COUPLE
OF HOURS. ONE TO THREE INCHES OF SNOW HAS BEEN COMMON SO FAR WHICH
IS IN LINE WITH FORECAST EXPECTATIONS...WITH SNOW-TO-LIQUID RATIOS
LIMITED SOMEWHAT BY A LACK OF STRONGER VERTICAL MOTION WITHIN THAT
FAVORABLE -12 TO -18 C DENDRITIC GROWTH ZONE. HOWEVER...THE GROUND
IS ALSO WARM AND THAT HAS BEEN REDUCING SNOW ACCUMULATION TOO WITH
A SLUSHY BASE UNDERNEATH THE SNOW OBSERVED HERE IN BILLINGS. THERE
WAS A DROP-OFF IN SNOWFALL AROUND MILES CITY EARLY IN THE NIGHT AS
FRONTOGENETICAL FORCING SAGGED SOUTHWARD AND AS OF THIS HOUR RADAR
TRENDS SUGGEST A SIMILAR SCENARIO IS TAKING PLACE FURTHER WESTWARD
INTO MUSSELSHELL...GOLDEN VALLEY AND WHEATLAND COUNTIES TOO. BASED
ON THOSE RADAR TRENDS AND THE CONSENSUS OF SHORT-TERM MODEL OUTPUT
WE DECIDED TO DROP THAT NORTHERN STRIP OF COUNTIES FROM THE WINTER
WEATHER ADVISORY WITH THIS FORECAST PACKAGE AS ADDITIONAL SNOWFALL
AFTER 12 UTC WILL BE UNDER AN INCH FROM HARLOWTON EASTWARD TO RYE-
GATE...ROUNDUP AND MILES CITY.
THE AREA OF COLDER CLOUD TOPS WHICH EARLIER COINCIDED WITH HEAVIER
SNOW AT BOZEMAN ARE LIKELY INDICATIVE OF THE STRONGER BATCH OF 500
TO 300 MB Q-VECTOR CONVERGENCE THAT GUIDANCE CONTINUES TO SHIFT TO
THE EAST-SOUTHEAST ALONG A LINE FROM LIVINGSTON TO SHERIDAN DURING
THE MORNING. THE SAME SHORT-TERM MODEL GUIDANCE THAT WAS MENTIONED
EARLIER...INCLUDING RECENT HRRR SIMULATIONS...PICKS UP ON THAT AND
WE WERE ABLE TO FOLLOW IT FOR THE SNOWFALL FORECAST IN THOSE AREAS
TOO. THAT MEANS WE ARE STILL BANKING ON ABOUT 2 MORE INCHES BEYOND
12 UTC FROM LIVINGSTON TO BILLINGS AND 4 TO 6 INCHES FOR THE FOOT-
HILLS LIKE AT RED LODGE AND SHERIDAN. SNOW-TO-LIQUID RATIOS SHOULD
CLIMB FROM THEIR OVERNIGHT AVERAGE AROUND 10 TO 1 INTO THE 15 TO 1
RANGE THIS MORNING BASED ON BUFKIT SNOW GROWTH VISUALIZATIONS...SO
THAT SHOULD HELP OUT ACCUMULATIONS. FORECAST-WISE...THIS WAS WELL-
HANDLED PREVIOUSLY...AND THE MAIN CHANGES WE MADE WERE TO DROP OFF
THE SNOW CHANCE MUCH MORE QUICKLY FROM NORTH TO SOUTH BEGINNING AT
18 UTC. FORECAST SOUNDINGS SHOW THE SATURATED LAYER SHRINKS RATHER
QUICKLY AND SO BY AFTERNOON PLACES LIKE BILLINGS COULD HAVE ONLY A
FEW FLURRIES LEFT. THUS...LATER FORECAST UPDATES SHOULD BE ABLE TO
DROP MORE OF THE REMAINING WINTER WEATHER ADVISORY EARLY.
BY TONIGHT...THE WEATHER WILL HAVE QUIETED DOWN CONSIDERABLY...BUT
WE MIGHT HAVE TO CONSIDER ADDING SOME FOG TO THE FORECAST IN LATER
RELEASES. THE 00 UTC NAM-BASED MOS /MET GUIDANCE/ SUPPORTED FOG IN
MANY PLACES INCLUDING BILLINGS...BUT THAT LACKS SUPPORT WITHIN THE
OTHER MODEL GUIDANCE AND SO CONFIDENCE WASN/T HIGH ENOUGH TO PUT A
MENTION OF FOG IN THE FORECAST. IT WILL BE A COLD NIGHT WITH FRESH
SNOW IN MANY AREAS...ESPECIALLY IF FOG DOES NOT DEVELOP.
ON FRIDAY...WE HAVE A LOW-END SNOW SHOWER CHANCE IN PLACE FOR PART
OF THE AREA AS A WEAK 500-MB SHORTWAVE TROUGH CROSSES THE AREA. IT
LOOKS LIKE WE WILL ONLY WARM INTO THE 20S F. SCHULTZ
.LONG TERM...VALID FOR SAT...SUN...MON...TUE...WED...
MAINLY DRY SATURDAY WITH SOME DOWNSLOPE COMPONENT TO THE PRESSURE
GRADIENT BUT NOT ENOUGH TO BRING WARMING GIVEN INFLUENCE OF SNOW
COVER. HEIGHTS SLOWLY FALLING IN THIS PERIOD IN ADVANCE OF A
SYSTEM SWINGING INTO THE PACIFIC NORTHWEST. THIS ENERGY BEGINS
SPREADING INTO THE AREA ON SUNDAY AND PHASES WITH THE ARRIVAL OF
AN ARCTIC COLD FRONT. LIFT WITH THIS SYSTEM WILL BE MORE RELATED
TO THE DEEPENING OF THE COLD AIRMASS WITH A LESS DYNAMIC SET UP
ALOFT. HOWEVER ITS A COLDER SYSTEM AND SNOWFALL RATIOS SHOULD BE
HIGHER. SNOWFALL AMOUNTS AROUND 4 INCHES SEEM REASONABLE FOR
LOWER ELEVATIONS BUT FOOTHILLS WILL SEE A FAVORABLE UPSLOPE
PATTERN SO HIGHER AMOUNTS COULD BE POSSIBLE.
WILL BE THE COLDEST AIRMASS OF DECEMBER AS A 1050MB HIGH SETTLES
IN SUNDAY NIGHT INTO MONDAY. THIS SHOULD YIELD SINGLE DIGIT HIGH
TEMPERATURES ON MONDAY WITH A CHANCE AT TEENS BELOW ZERO MONDAY
NIGHT. SNOW COULD LINGER INTO MONDAY MORNING BUT WILL END DURING
THE DAY.
TUESDAY SHOULD INITIATE A WARMING TREND AS THE HIGH DIGS SOUTH OF
THE REGION AND PATTERN SUPPORTS A DOWNSLOPE FLOW BUT AIRMASS WILL
STILL BE PRETTY COLD. BETTER TEMPERATURE RECOVERY CAN BE EXPECTED
WEDNESDAY BUT TEMPERATURES SHOULD STILL BE BELOW NORMAL. BORSUM
&&
.AVIATION...
SNOW WILL IMPACT KBIL KSHR AND KLVM THIS MORNING BUT SNOW HAS
LARGELY ENDED FOR KMLS. AREAS OF SNOW S AND W OF AND INCLUDING
KBIL WILL CAUSE WIDESPREAD IFR AND AREAS OF LIFR CONDITIONS UNTIL
17Z. CONDITIONS WILL IMPROVE DURING THE AFTERNOON. NORTH AND EAST
OF KBIL EXPECT AREAS OF MVFR CONDITIONS MOSTLY DUE TO CEILINGS.
BORSUM
&&
.PRELIMINARY POINT TEMP/POPS...
TDY FRI SAT SUN MON TUE WED
-------------------------------------------------------
BIL 028 006/025 009/026 016/021 904/006 914/008 903/027
+/S 21/B 11/B 25/J 52/J 21/B 11/N
LVM 028 901/026 002/027 014/024 908/011 915/016 003/030
+/S 51/B 12/J 45/J 42/J 21/B 11/N
HDN 028 004/025 003/026 014/023 904/007 915/009 907/025
+/S 22/J 11/B 25/J 52/J 22/J 11/N
MLS 027 011/024 011/027 017/021 000/008 905/010 002/025
4/S 12/J 11/B 14/J 42/J 11/B 11/B
4BQ 027 007/024 006/026 013/024 901/009 910/007 901/024
+/S 22/J 10/B 14/J 53/J 21/B 11/B
BHK 024 009/022 009/026 013/019 903/006 906/008 000/022
3/S 11/B 11/B 13/J 42/J 11/B 11/B
SHR 027 903/022 902/025 010/024 902/012 912/019 901/029
+/S 61/B 10/B 15/J 63/J 21/B 11/B
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...WINTER WEATHER ADVISORY IN EFFECT UNTIL 5 PM MST THIS
AFTERNOON FOR ZONES 30-34>37-39>41-57-58-64-65.
WINTER STORM WARNING IN EFFECT UNTIL 5 PM MST THIS AFTERNOON
FOR ZONES 38-56-66-67.
WY...WINTER WEATHER ADVISORY IN EFFECT UNTIL 5 PM MST THIS
AFTERNOON FOR ZONE 98.
WINTER STORM WARNING IN EFFECT UNTIL 5 PM MST THIS AFTERNOON
FOR ZONE 99.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS HASTINGS NE
943 PM CST FRI DEC 26 2014
.UPDATE...
ISSUED AT 914 PM CST FRI DEC 26 2014
SENT AN UPDATE TO THE FORECAST TO REFINE THE TIMING OF PRECIP
THROUGH THE OVERNIGHT HOURS...LINGERING SOME LIGHT ACCUMULATING
SNOWFALL ACROSS OUR NORTHERN COUNTIES THROUGH THE EARLY MORNING
HOURS SATURDAY WHERE THE ADVISORY WAS RECENTLY EXTENDED. LATEST
SATELLITE IMAGERY SHOWS THE UPPER LEVEL LOW ACROSS WESTERN
NEBRASKA BEGINNING TO PIVOT AND LIFT NORTHEASTWARD...WHICH SHOULD
RESULT IN SNOWFALL TAPERING OFF FROM SOUTH TO NORTH OVERNIGHT.
FOLLOWED 02Z RAP GUIDANCE FAIRLY CLOSELY WITH TIMING OF PRECIP AND
TEMPERATURES OVERNIGHT...WITH NO CHANGES MADE TO THE PREVIOUS
FORECAST BEYOND THE OVERNIGHT HOURS.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 324 PM CST FRI DEC 26 2014
WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL MIDNIGHT TONIGHT.
AT 21Z...SNOWFALL WAS ONGOING ACROSS PARTS OF OUR WESTERN AND
SOUTHWESTERN COUNTIES. SNOWFALL WILL CONTINUE TO OVERSPREAD AREAS
EAST THROUGHOUT THE REST OF THE AFTERNOON AND INTO THE EVENING
HOURS. ACROSS THE ADVISORY AREA...2 TO 4 INCHES IS EXPECTED...AND
GENERALLY 1 TO 3 ACROSS THE REST OF THE OUTLOOK AREA. FOR THE HEART
OF THE CWA...WHICH IS BASICALLY THE TRI-CITIES...WE ARE CONFIDENT
THE HEAVIEST SNOWFALL WILL LIKELY FALL BETWEEN 6PM AND 9 PM TONIGHT.
SNOWFALL WILL CONTINUE UNTIL ABOUT 11PM/MIDNIGHT BEFORE TAPERING
OFF. FOR 00Z...FORECAST SOUNDINGS FOR GRAND ISLAND SHOWED THE
STRONGEST OMEGA VALUES WHICH COINCIDED WITH A MOIST DGZ
LAYER...HENCE THE CONFIDENCE FOR HEAVIEST SNOWFALL DURING THIS TIME.
ALSO HELPING CREATE A FAVORABLE TIME FRAME FOR HEAVIEST SNOW AROUND
00Z IS AN AREA OF ISENTROPIC LIFT CENTERED THROUGH MOST OF THE
CWA...ALBEIT THIS TIME FRAME IS LIMITED TO ABOUT 3 HOURS.
THEREAFTER...WE QUICKLY BEGIN TO LOSE FORCING AND MOISTURE...SO
CONFIDENT SNOW WILL RETREAT FROM THE SOUTHWEST TO NORTHEAST BETWEEN
MIDNIGHT AND SUNRISE SATURDAY MORNING.
CLOUD COVER WILL SLOWLY DECREASE LATE SATURDAY MORNING/EARLY
AFTERNOON...AND WE SHOULD SEE SOME SUNNY SKIES MID TO LATE SATURDAY
AFTERNOON. HIGHS WILL BE ON THE COOL SIDE...WITH MID/UPPER 20S TO
LOWER 30S CURRENTLY FORECAST. LOWS TONIGHT WILL GENERALLY RANGE
BETWEEN THE TEENS AND LOWER 20S.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 324 PM CST FRI DEC 26 2014
SUGGEST HAVING THE HEAVY WINTER COATS/GLOVES/HATS READY AND THOSE
WHO USE WOOD STOVES FOR HEAT KEEP PLENTY OF WOOD CLOSE BY. WE ARE IN
FOR ANOTHER PERIOD OF SERIOUS WINTER COLD...BUT THIS TIME MUCH
COLDER THAN NOV!
THE COLDEST HIGH TEMP IN GRAND ISLAND /GRI/ WAS 20F ON THE NOV 17TH.
WE WILL EXPERIENCE THE COLDEST AIR SO FAR THIS COLD SEASON. WE HAVE
TWO DAYS IN THIS FCST IN WHICH HIGHS WILL BE COLDER THAN 20F.
NOT QUITE CONFIDENT YET TO STATE HOW MANY CONSECUTIVE DAYS TEMPS
COULD REMAIN AT OR BELOW FRZG. DOWNSLOPE WARMING IS ALWAYS A
WILDCARD BETWEEN ARCTIC FRONTAL PASSAGES AS THE HIGHS DROP S OF THE
REGION. SUFFICE TO SAY THERE COULD BE A 1 OR 2 DAY INTERRUPTION...
BUT OVERALL BELIEVE WE ARE LOOKING AT AN EXTENDED STRETCH OF COLD
WX BEGINNING MON.
MODELS: THE EC/GFS/UKMET/GEM AND THE ENSEMBLE MEANS CONT IN VERY
GOOD AGREEMENT ON THE OVERALL PATTERN THRU FRI 1/2 AND ALL THE
WAY OUT THRU 10 DAYS.
THE LONGWAVE FLOW WILL BE HIGHLY AMPLIFIED WITH A RIDGE OVER THE NE
PAC INTO AK WITH A DOWNSTREAM +TILT TROF FROM HUDSON BAY INTO THE
WRN USA. THIS IS THE PATTERN WE SAW IN NOV AND IT WILL DELIVER BELOW
NORMAL TEMPS NEXT WEEK...WITH A COUPLE TWO-DAY PERIODS OF MUCH BELOW
NORMAL BITTER COLD. THAT MEANS DAYTIME HIGHS IN THE SINGLE DIGITS AND
TEENS WHICH WILL BE 20-25F COLDER THAN NORMAL. AS OF NOW THE COLDEST
DAYS ARE SLATED FOR 12/30-31 WITH HIGH CONFIDENCE AND 1/3-4 WITH
LOW CONFIDENCE.
ALOFT: A BROAD TROF WITH GENERALLY W FLOW WILL BE OVER THE PLAINS
THRU TUE. A SHORTWAVE TROF IS CURRENTLY CRESTING THE RIDGE OVER THE
GULF OF AK. THIS TROF WILL DIVE INTO THE WRN USA SAT-MON AND CUT-OFF
OVER CA TUE...GRADUALLY SINKING INTO THE DESERT SW THRU FRI.
CONFLUENT NW FLOW WILL DEVELOP OVER THE CNTRL USA IN THE MEANTIME.
ANOTHER SHORTWAVE TROF DIVING THRU WRN N AMERICA LATE NEXT WEEK
SHOULD KICK THIS LOW E...RESULTING IN A SIZABLE STORM FOR THE CNTRL/
ERN USA AND ANOTHER COLD SURGE. LOOKS LIKE THE NEXT WX-MAKER WILL BE
A WEAK SHORTWAVE TROF SUN NIGHT INTO MON.
SURFACE: HIGH PRES WILL BE OVERHEAD SAT EVE AND DRIFT S AND E OF THE
REGION OVERNIGHT WHILE THE LEADING EDGE OF THE ARCTIC AIR SPILLS
INTO THE NRN USA. THE FRONT WILL MOVE THRU SUN NIGHT WITH BITTERLY
COLD ARCTIC HIGH PRES OVER WRN CANADA SLOWLY SLIDING DOWN THE FRONT
RANGE. THIS HIGH WILL BE OF THE 1050+ MB VARIETY AND WILL BE
OVERHEAD DAYBREAK WED. IT THEN HEADS INTO THE SRN USA THU-FRI. AN
ALBERTA CLIPPER WILL DIVE SE INTO THE NRN PLAINS HERALDING THE NEXT
SURGE OF ARCTIC AIR WITH ITS ARRIVAL PROBABLY NEXT WEEKEND. SRN
PLAINS CYCLOGENESIS APPEARS IN THE OFFING LATE NEXT WEEK. THIS WILL
BEEN TO BE WATCHED.
THE DAILY DETAILS...
PLEASE GIVE US SOME LATITUDE ON TEMPS. FRESH SNOWCOVER IS ALWAYS A
SIGNIFICANT COMPLICATION ON TEMP FORECASTING.
SUN: A SUNNY START...BUT INCREASING MULTI-LAYERED MID-HIGH CLOUDS.
SUN NIGHT: ARCTIC COLD FRONTAL PASSAGE.
MON: CLOUDY/BLUSTERY AND COLD. STEADY OR SLOWLY FALLING TEMPS IN
COLD AIR ADVECTION. FOR MOST LOCATIONS DAYTIME HIGHS WILL OCCUR AT
DAWN. N WINDS WILL GUST TO 30 MPH AT TIMES. COULD SEE A BURST OF
LIGHT SNOW WITH THE WEAK SHORTWAVE TROF AND DEEP MOISTURE.
CANT RULE OUT A WIND-BLOWN INCH OR SO BUT IT/S WAY TOO EARLY AND THE
POTENCY ALOFT IS LACKING. FOR WHAT IT/S WORTH THE 06Z/12Z GFS
INDICATE THIS POTENTIAL...BUT THE SREF PROBABILITIES FOR .10" QPF
ARE CURRENTLY HIGHEST ALONG THE NEB-SD BORDER.
TUE: BITTERLY COLD. HIGHS ONLY IN THE SINGLE DIGITS FOR MUCH OF S-
CNTRL NEB. MID TEENS FOR N-CNTRL KS. WATCH YOUR HOME BAROMETERS. IF
IT/S ARE CALIBRATED...YOU WILL LIKELY SEE PRESSURE EXCEEDING 30.80".
WED: COULD BE A VERY VERY COLD START AS LONG AS CLOUDS ARE NOT A
FACTOR. COLDEST LOCATIONS WOULD BE THE USUAL COLD SPOTS N AND W OF
THE TRI-CITIES...ESPECIALLY THE LOUP RVR VALLEY. HIGH PRES OVERHEAD
TUE NIGHT WOULD RESULT IN VERY LIGHT WINDS.
THU-FRI: MODERATING TEMPS. DRY THU AND PROBABLY FRI. BUT FRI NEEDS
TO BE WATCHED AS LOW PRES WILL BE ORGANIZING S OF THE REGION. GFS
ENSEMBLES SUGGEST THIS LOW WILL MISS WELL SE OF THE FCST AREA... BUT
A LOT CAN CHANGE BETWEEN NOW AND THEN.
&&
.AVIATION...(FOR THE 00Z KGRI/KEAR TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 536 PM CST FRI DEC 26 2014
GENERALLY POOR CONDITIONS WILL PREVAIL AT BOTH TERMINALS THROUGH
THE EVENING HOURS AS IFR CIGS/VSBYS ARE EXPECTED IN BANDS OF
MODERATE SNOWFALL THROUGH AROUND 27/04Z. THEREAFTER...THE HEAVIER
SNOWFALL IS EXPECTED TO TAPER OFF...WITH PREVAILING MVFR CIGS
EXPECTED THROUGH THE REMAINDER OF THE OVERNIGHT HOURS...WITH SOME
ADDITIONAL LIGHT SNOWFALL EXPECTED FROM TIME TO TIME. BEHIND THIS
SYSTEM...EXPECT A RETURN TO VFR CONDITIONS DURING THE DAY
SATURDAY...WITH GUSTY NORTHERLY WINDS THIS EVENING EXPECTED TO
RELAX AND BECOME MORE WESTERLY THROUGH THE DAY TOMORROW.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR NEZ041-
046>048-060>062-072>074-082-083.
WINTER WEATHER ADVISORY UNTIL 4 AM CST SATURDAY FOR NEZ039-040.
KS...NONE.
&&
$$
UPDATE...ROSSI
SHORT TERM...GUERRERO
LONG TERM...HALBLAUB
AVIATION...ROSSI
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
910 PM CST FRI DEC 26 2014
.UPDATE...
ISSUED AT 910 PM CST FRI DEC 26 2014
JUST UPDATED THE CURRENT FORECAST AND HEADLINES TO REFLECT THE
CURRENT WEATHER SITUATION AS WELL AS TO ACCOUNT FOR THE LATEST NAM
AND RUC MODEL SOLUTIONS. RADAR IMAGERY CONTINUES TO SHOW A LARGE
AREA OF SNOW ACROSS WESTERN AND NORTH CENTRAL NEBRASKA TONIGHT. A
TRAILING PV LOBE WAS NOTED JUST NORTH OF IMPERIAL AS OF 9 PM CST
PER RADAR IMAGERY. THIS FEATURE WILL QUICKLY MOVE TO THE NORTHEAST
OVER THE NEXT 3 TO 6 HOURS. AS IT DOES...SNOW WILL COME TO AN END
BEHIND THE VORT LOBE OVERNIGHT. THE LATEST NAM AND RUC
SOLNS...HOLD ONTO SNOW ACROSS THE NORTHEASTERN FORECAST AREA AFTER
MIDNIGHT...SO EXTENDED THE WINTER WEATHER ADVISORY FOR
HOLT...BOYD...WHEELER AND GARFIELD COUNTIES THROUGH 4 AM CST.
ADDITIONAL SNOW ACCUMULATIONS WILL RANGE FROM A HALF TO AN INCH
OVER SOUTHWESTERN NEBRASKA...TO 2 TO 3 ADDITIONAL INCHES ACROSS
FAR NORTHEASTERN PORTIONS OF THE FORECAST AREA. TOTAL
ACCUMULATIONS OF 3 TO 6 INCHES STILL REMAINS ON TRACK THROUGH
TONIGHT.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 330 PM CST FRI DEC 26 2014
PV ANOMALY TRACKING THROUGH NORTHERN NEW MEXICO LATE THIS AFTERNOON
PER WATER VAPOR IMAGERY. UPPER LEVEL LOW PRESSURE CIRCULATION WAS
LOCATED JUST NORTH OF THIS ACROSS FAR SOUTH CENTRAL COLORADO. THIS
FEATURE WILL LIFT NORTHEAST ACROSS WESTERN KANSAS INTO CENTRAL
NEBRASKA TONIGHT. A BAND OF SNOW HAS BEEN PERSISTENT IN REGION OF
MID LEVEL FRONTOGENESIS FROM ONEILL TO NORTH PLATTE FOR MUCH OF THE
DAY. THIS BAND MAY WEAKEN SOME THIS AFTERNOON...BUT LIFT WILL
INCREASE AGAIN LATE THIS AFTERNOON AND EVENING AS THE UPPER LEVEL
LOW CENTER APPROACHES AND THEN CROSSES THE AREA TONIGHT. THIS WILL
KEEP SNOW PRODUCTION GOING THROUGH AT LEAST MID EVENING...AND EXPECT
AT LEAST LINGERING LIGHT SNOW THROUGH MIDNIGHT. SNOW TO LIQUID
RATIOS HAVE BEEN ABOUT 15:1 TO 20:1 OR SO THUS FAR...AND EXPECT
THOSE RATIOS TO BE CLOSER TO 20:1 INTO THIS EVENING. SO AS THE
SECOND BAND OF SNOW LIFTS THROUGH THE AREA WITH THE UPPER LEVEL LOW
THIS EVENING...EXPECT ANOTHER 1 TO 3 INCHES OF ADDITIONAL
ACCUMULATION...WITH TOTAL SNOWFALL OF 3 TO 6 INCHES BY THE TIME THE
SNOW ENDS LATE TONIGHT.
SURFACE HIGH PRESSURE CONTINUES TO BUILD INTO THE AREA THROUGH
TONIGHT...WITH THE PRESSURE GRADIENT DECREASING. AS A RESULT WINDS
WILL NOT INCREASE ANY THIS EVENING...AND IN FACT WIND SPEEDS WILL BE
SLOWLY DECREASING. SO FORTUNATELY BLOWING AND DRIFTING SNOW WILL NOT
BE A MAJOR PROBLEM. GOING WINTER WEATHER ADVISORY LOOKS GOOD...AND
NO PLANS TO CHANGE HEADLINES.
DRIER AIR WILL STREAM INTO THE AREA IN THE MID AND UPPER LEVELS OF
THE ATMOSPHERE SATURDAY...AND EXPECT AT LEAST SOME SUNSHINE. WINDS
WILL BE LIGHT WITH SURFACE HIGH PRESSURE IN CONTROL.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 330 PM CST FRI DEC 26 2014
BITTERLY COLD TEMPERATURES ARE ANTICIPATED THROUGHOUT THE ENTIRE
EXTENDED FORECAST...WITH THE COLDEST AIR OF THE SEASON SHOWN TO
ARRIVE EARLY NEXT WEEK. HIGHS MAY STRUGGLE TO REACH INTO THE
SINGLE DIGITS ON MONDAY AND TUESDAY FOR MOST LOCATIONS.
THE EXTENDED MODELS REMAIN IS SOLID AGREEMENT WITH THE EVOLUTION OF
THE UPPER PATTERN THIS WEEKEND AND INTO NEXT WEEK....WHICH ALL POINT
TO RE-ENFORCING SHOTS OF ARCTIC AIR DIVING SOUTH ACROSS THE
INTERMOUNTAIN WEST AND PLAINS. WEAK SUBSIDENCE TO START THE DAY
SUNDAY WILL KEEP THE FORECAST DRY...AS COOL AS HIGH PRESSURE SITS
ATOP THE REGION. BY SUNDAY EVENING HOWEVER A SHORTWAVE WILL DIG
SOUTHEAST FROM THE NORTHERN ROCKIES AND DRAG A ARCTIC FRONT SOUTH
ACROSS THE PLAINS. LIGHT SNOW IS SHOWN TO DEVELOP ALONG AND BEHIND
THE FRONTAL PASSAGE...SPREADING NORTH TO SOUTH ACROSS THE ENTIRE
FORECAST AREA. AT THIS POINT SNOW ACCUMULATIONS LOOK TO REMAIN
LIGHT...WITH AT MOST A COUPLE INCHES ACROSS OUR NORTHERN
ZONES...LESS FURTHER SOUTH. THE COLD FRONT WILL BE SOUTH OF THE
FORECAST AREA BY 12Z MONDAY AND UNDER A STRONG COLD AIR ADVECTION
REGIME...HIGHS WILL STRUGGLE TO REACH INTO THE SINGLE DIGITS BOTH
MONDAY AND TUESDAY...WITH WIDESPREAD SUBZERO LOWS. THE COLDEST
TEMPERATURES WILL OCCUR EARLY ON WEDNESDAY AS A 1050MB HIGH DRIFTS
SOUTH ALONG THE LEE OF THE CENTRAL ROCKIES. DOUBLE DIGIT SUB ZERO
LOWS ARE POSSIBLE FOR MUCH OF THE AREA. THERE WILL BE A SLIGHT
REPRIEVE FROM THE BITTERLY COLD TEMPERATURES LATE WEEK AS A TROUGH
CUTS OFF A LOW OVER THE DESERT SOUTHWEST. THIS WILL PLACE THE
FORECAST AREA UNDER THE INFLUENCE OF SW FLOW IN THE LOWER LEVELS.
TEMPERATURE WOULD THEN MODERATE SOME...WITH HIGHS APPROACHING
SEASONAL NORMS.
THE STRONGEST WINDS DURING THE LONG RANGE PERIOD LOOK TO COME MONDAY
BEHIND THE FRONT...BUT EVEN WITH LIGHT WIND SPEEDS FORECAST THROUGH
WEDNESDAY...DANGEROUSLY COLD APPARENT TEMPERATURES ARE ANTICIPATED
AND FORECAST FOR THE OVERNIGHTS ON MONDAY...TUESDAY...AND WEDNESDAY.
APPROPRIATE WIND CHILLS HEADLINES ARE EXPECTED.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 545 PM CST FRI DEC 26 2014
AN UPPER LEVEL TROUGH OF LOW PRESSURE WILL LIFT ACROSS
SOUTHWESTERN AND CENTRAL NEBRASKA THIS EVENING. LIGHT SNOW WILL BE
POSSIBLE AT THE KLBF TERMINAL THIS EVENING...ENDING IN THE
OVERNIGHT HOURS. FOR THE KLBF TERMINAL...THROUGH 08Z
TONIGHT...LIGHT SNOW WITH VISBYS RANGING FROM 1 TO 3SM ARE LIKELY.
CIGS WILL RANGE FROM 1200 TO 2500 FT AGL THROUGH THIS TIME. SKIES
WILL BEGIN TO CLEAR OVERNIGHT WITH SCATTERED CIGS AT 25000 FT AGL
EXPECTED AFTER 12Z SATURDAY. FOR THE KVTN TERMINAL...EXPECT MVFR
CIGS OF 1500 FT AGL THIS EVENING WITH CIGS AROUND 10000 FT
EXPECTED OVERNIGHT TONIGHT THROUGH 15Z SATURDAY. SKIES WILL CLEAR
BY MID MORNING SATURDAY AND REMAIN CLEAR THROUGH 00Z SUNDAY.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST /11 PM MST/ TONIGHT
FOR NEZ008-009-025>027-036>038-057>059-069>071.
WINTER WEATHER ADVISORY UNTIL 4 AM CST SATURDAY FOR NEZ007-010-
028-029.
&&
$$
UPDATE...CLB
SHORT TERM...TAYLOR
LONG TERM...JACOBS
AVIATION...CLB
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1149 AM CST THU DEC 25 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 404 AM CST THU DEC 25 2014
THERMAL AND MOISTURE PROFILES LOOK GOOD FOR SNOW ACROSS SHERIDAN
COUNTY. LIFT IS DEEP BUT JUST 5 MICROBARS SUPPORTING THE MODERATE
SNOW FORECAST TOTALS NEAR 5 INCHES BY FRIDAY MORNING...MAINLY
ALONG PINE RIDGE. THE FRONTOGENESIS IS MODEST IN THE NAM. FARTHER
EAST THERE IS EVIDENCE OF A 700MB DRY SLOT NEAR VALENTINE WHICH
WOULD GREATLY LIMIT SNOWFALL. THE FORECAST SHOWS A FAIRLY SHARP
CUTOFF ASSOCIATED WITH THIS DRY INTRUSION. THE SNOWFALL FORECAST
IS MARGINAL ALONG THE ERN FLANK OF THE WINTER WEATHER ADVISORY BUT
GIVEN IT WILL MOSTLY OCCUR AFTER NIGHTFALL THE ADVISORY WILL BE
ALLOWED TO STAND WITH NO CHANGES.
THE MODELS APPEAR TO HAVE TRENDED NORTH SOMEWHAT FAVORING SHERIDAN
COUNTY AND THE FORECAST CENTROID OF HIGHEST SNOWFALL IS NORTHWEST OF
THE HPC FORECAST.
MEANWHILE THE RAP13 AND THE 06Z NAM ARE TAKING THE
BETTER FOCUS ACROSS THE WRN CHEYENNE DIVIDE AND TOWARD THE HIGHER
TERRAIN NORTH OF SCOTTSBLUFF WHICH IS SOUND. THIS METEOROLOGICAL
WOBBLING WILL LIKELY CONTINUE TODAY. THE LATEST RADAR AND OBS ACROSS
WRN SD INDICATE SNOW IS NOW UNDERWAY...ABOUT 5 HOURS SOONER THAN
FORECAST WHICH SUPPORTS THE OFFICIAL FORECAST. THE NAM MODEL SHOWS
FORCING ACROSS NW NEB THIS EVENING AROUND 03Z WHICH LIFTS EAST INTO
ERN SD BY 06Z. THE RAP WEAKENS THIS DISTURBANCE VERY QUICKLY AND
RAPIDLY SETS UP A CLOSED H700MB LOW NEAR CHEYENNE. THERE IS WOBBLING
IN THE MODELS BUT THIS IS NORMAL AND THE FORECAST FOLLOWS THE MODEL
CONSENSUS.
SATELLITE WATER VAPOR SHOWS A VIGOROUS UPPER LOW DROPPING THROUGH
THE CNTL ROCKIES THIS MORNING. THIS STORM IS BEING FUELED BY A HIGH
QUALITY SUBTROPICAL RIVER OF MOISTURE OFF OF HAWAII SUGGESTING THERE
COULD BE ROOM FOR SURPRISE SNOWFALL AMOUNTS...SOMEWHERE. THE
NATIONAL WEATHER HAZARDS MAP SHOWS AN INCREASE IN WINTER STORM
WARNINGS ACROSS THE CNTL ROCKIES.
THE LATEST WIND FORECAST INDICATES NORTH WINDS AT 15 TO 20 MPH
GUSTING TO NEAR 30 MPH. THIS IS ABOUT 5 MPH LESS THAN THE PREVIOUS
FORECAST. THE 00Z ECM WAS THE ONLY MODEL INDICATING 25 MPH WIND
SPEEDS. BLOWING SNOW IS INCLUDED IN THE FORECAST TONIGHT WHICH IS
CONSISTENT WITH AND WIND SPEEDS APPROACHING 25 MPH.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 404 AM CST THU DEC 25 2014
THIS PORTION OF THE FORECAST BEGINS WITH ONGOING PRECIPITATION
ACROSS WESTERN AND NORTH CENTRAL NEBRASKA ASSOCIATED WITH THE
UPPER LEVEL TROUGH CURRENTLY WITH ITS BASE OVER CENTRAL CALIFORNIA
AND EXTENDING NORTH THROUGH IDAHO. BY 12Z FRIDAY...THE BASE OF THE
TROUGH IS EXPECTED TO HAVE MOVED EAST AND BE OVER ARIZONA.
MEANWHILE...ANOTHER SHORTWAVE TROUGH FROM THE NORTHERN STREAM
WOULD BE MOVING INTO MONTANA.
ON FRIDAY MORNING SNOW OVER NORTHWEST NEBRASKA SHOULD BE WINDING
DOWN AS THE LEAD SHORTWAVE TROUGH THAT WILL MOVE ACROSS THE AREA
TONIGHT MOVES EAST INTO THE UPPER MISSISSIPPI RIVER VALLEY. CROSS
SECTIONS SHOW THE AMOUNT OF LIFT ACROSS THIS AREA DIMINISHING FRIDAY
MORNING...WITH THE DEEP MOISTURE ALSO ON THE WAYSIDE BY 18Z AS DRY
AIR STARTS TO ADVECT INTO NORTHWEST NEBRASKA BEHIND THE SHORTWAVE.
ADDITIONAL SNOW AMOUNTS OVER THE AREAS IN THE WINTER WEATHER
ADVISORY WILL BE MINIMAL ON FRIDAY AND AS WINDS GO DOWN THROUGH THE
DAY...ENDING THE ADVISORY AT 18Z CONTINUES TO LOOK APPROPRIATE.
LOOKING FURTHER SOUTH AND EAST AT 12Z...THE COLUMN ISN/T COMPLETELY
SATURATED AS THE MODELS ARE SHOWING DRY AIR IN THE MID LEVELS...FROM
750MB TO 600MB. SATURATION IS SEEN THOUGH BELOW 750MB BUT THE DRY
LAYER LOOKS TOO DEEP TO PROVIDE A SEEDER/FEEDER PROCESS. THERE IS
INDICATION THAT LIFT IN THIS LAYER INCREASES LATE THURSDAY NIGHT AND
FRIDAY MORNING WHICH COULD INDICATE POTENTIAL FOR FREEZING DRIZZLE
AS NO ICE WOULD BE INTRODUCED INTO THAT LAYER. HOWEVER...THE
MOISTURE QUICKLY INCREASES AFTER 12Z AND WITH LITTLE CONFIDENCE ON
THIS HAVE NO MENTION IN THE FORECAST AT THIS TIME AND HAVE ONLY
SNOW.
THROUGH THE DAY FRIDAY AND SATURDAY...THE UPPER LEVEL TROUGH IS
EXPECTED TO BECOME ELONGATED AS A 120KT-130KT JET SHEARS IT INTO
SEVERAL PIECES. THE MODELS ARE IN GOOD AGREEMENT WITH THIS
OCCURRING....WITH THE FIRST PIECE OF ENERGY MOVING UP THROUGH KANSAS
AND INTO EASTERN NEBRASKA BY SATURDAY MORNING. THEN DURING THE DAY
SATURDAY...THIS SHORTWAVE TROUGH PHASES TOGETHER WITH THE SHORTWAVE
MOVING OUT OF MONTANA ACROSS CENTRAL AND EASTERN NEBRASKA.
SNOW IS EXPECTED TO INCREASE IN COVERAGE AND INTENSITY OVER THE
SOUTHERN PART OF THE FORECAST AREA LATE FRIDAY MORNING AND AFTERNOON
AS LIFT INCREASES DUE TO THE SHORTWAVE TROUGH MOVING THROUGH KANSAS
AND THE EASTERN PART OF NEBRASKA. CURRENT MODELS SHOW THE 8-12
UBAR/S OF OMEGA THROUGH THE DENDRITIC GROWTH ZONE ACROSS SOUTHERN
NEBRASKA WHICH COULD LEAD TO SLIGHTLY HIGHER THAN NORMAL SNOW TO
LIQUID RATIOS /16:1 TO 19:1/. SO...DESPITE QPF AMOUNTS NOT BEING
SIGNIFICANT FRIDAY AND FRIDAY NIGHT /0.10 TO 0.20 INCHES/ COULD GET
UP TO 3 INCHES IN SOME PARTS OF THE AREA BY SATURDAY MORNING. COLD
AIR ADVECTION WILL BE ONGOING THROUGH THE DAY FRIDAY AND WITH CLOUDS
AND SNOW DON/T EXPECT TEMPERATURES TO WARM MUCH. PRIOR FORECAST HAD
HIGHS IN THE UPPER TEENS TO MID 20S WHICH STILL LOOK GOOD AND ONLY
MINOR MODIFICATIONS WERE MADE.
AS THE MONTANA SHORTWAVE PUSHES THROUGH SUBSIDENCE WILL START TO DRY
THINGS OUT OVER NORTHWEST NEBRASKA BY SATURDAY MORNING. NOT ENTIRELY
CONFIDENT ON HOW MUCH CLOUDS WILL REMAIN BY 12Z...BUT IF SKIES DO
CLEAR...WITH A GOOD SNOWPACK ON THE GROUND TEMPERATURES COULD DROP
TO NEAR 0F. HIGH PRESSURE BUILDS INTO THE REGION ON SATURDAY WHICH
WILL BRING AN END TO ALL OF THE SNOW AND ALSO DIMINISH THE WINDS.
TEMPERATURES SHOULD BE A BIT WARMER BUT NOT BY MUCH...WITH HIGHS
LIKELY IN THE 20S.
QUIET CONDITIONS WILL BE SEEN FOR THE REMAINDER OF THE WEEKEND...BUT
ANOTHER STRONG SYSTEM WILL MOVE INTO THE PACIFIC NORTHWEST SATURDAY
NIGHT AND WILL DIG SOUTH INTO THE SOUTHWEST CONUS. THE MODELS ARE IN
DECENT AGREEMENT AND CONTINUE TO BRING SOME VERY COLD AIR DOWN INTO
THE PLAINS BEHIND A COLD FRONT PUSHED BY THIS SYSTEM. THE FRONT
LOOKS TO MOVE SOUTH ACROSS NEBRASKA LATE SUNDAY NIGHT AND MONDAY.
THIS ARCTIC FRONT WILL BRING AN AIRMASS WITH 850MB TEMPERATURES DOWN
AROUND -20C INTO THE AREA /COMPARED TO THE LATEST OBSERVATION AT
KLBF OF 2C/. HIGHS ON TUESDAY COULD BE QUITE COLD...ONLY IN THE
SINGLE DIGITS. THAT BEING SAID...DESPITE THE AGREEMENT IN THE
MODELS...THE GFS ENSEMBLES ARE SHOWING A LARGE DEGREE OF
SPREAD...WITH A STANDARD DEVIATION OF 9 FOR TUESDAY/S HIGHS...WITH A
RANGE FROM 0F TO 42F OVER THE NORTHWEST PART OF THE FORECAST AREA.
BELIEVE THE COLDER ROUTE IS THE WAY TO GO WITH THE AGREEMENT IN A
COLD AIRMASS MOVING IN AND WITH DEEP SNOWPACK TO HELP REDUCE
TEMPERATURE RISES. IN ADDITION...THERE WILL BE CHANCES FOR SNOW
AGAIN EARLY NEXT WEEK BEHIND THE PASSING OF THE ARCTIC FRONT.
NOTHING SIGNIFICANT FOR SNOW AMOUNTS IS EXPECTED AT THIS TIME BUT
WILL CONTINUE TO MONITOR FOR ANY CHANGES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1149 AM CST THU DEC 25 2014
COMPLICATED AVIATION FORECAST AS THE MODELS DEVELOP TWO SEPARATE
BANDS OF SNOW DURING THE 18Z AVIATION FORECAST PERIOD...EACH OF
WHICH WILL BRING SNOW...LOWERED CEILINGS AND REDUCED VISIBILITIES
TO PORTIONS OF THE FORECAST AREA. RIGHT NOW...SNOW AND FZFG IS
SPREADING EAST ACROSS NORTHWESTERN NEBRASKA. KVTN HAS LOWERED BELOW
1SM AS FZFG IMPACTS THE SITE...THE PERIOD OF FOG SHOULD BE BRIEF
HOWEVER...AS SNOW WILL BECOME THE PRIMARY IMPACT LATE THIS
AFTERNOON. SNOW WILL CONTINUE ACROSS NORTHERN NEBRASKA AND THE
WESTERN SANDHILLS INTO THE OVERNIGHT. FRIDAY...THE SECOND BAND
WILL DEVELOP ACROSS SOUTHWEST NEBRASKA DURING THE 12-15Z
TIME FRAME...AND THEN SPREAD NORTHEAST ACROSS KLBF AND KBBW BY
EARLY AFTERNOON /RIGHT AT OR JUST BEFORE 18Z/. SNOW...REDUCED
VISIBILITY AND LOWERED CEILINGS ARE ANTICIPATED ONCE AGAIN. A
PERIOD OF FZDZ MAY BE A CONCERN AS WELL...BUT CONFIDENCE WAS NOT
SUFFICIENT ENOUGH FOR A MENTION IN THE FORECAST. ALL IN ALL FORECAST
UPDATES ARE ANTICIPATED.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL NOON CST /11 AM MST/ FRIDAY FOR
NEZ004-005-022>024-035-056-094.
&&
$$
SHORT TERM...CDC
LONG TERM...BROOKS
AVIATION...JACOBS
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
526 AM CST THU DEC 25 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 404 AM CST THU DEC 25 2014
THERMAL AND MOISTURE PROFILES LOOK GOOD FOR SNOW ACROSS SHERIDAN
COUNTY. LIFT IS DEEP BUT JUST 5 MICROBARS SUPPORTING THE MODERATE
SNOW FORECAST TOTALS NEAR 5 INCHES BY FRIDAY MORNING...MAINLY
ALONG PINE RIDGE. THE FRONTOGENESIS IS MODEST IN THE NAM. FARTHER
EAST THERE IS EVIDENCE OF A 700MB DRY SLOT NEAR VALENTINE WHICH
WOULD GREATLY LIMIT SNOWFALL. THE FORECAST SHOWS A FAIRLY SHARP
CUTOFF ASSOCIATED WITH THIS DRY INTRUSION. THE SNOWFALL FORECAST
IS MARGINAL ALONG THE ERN FLANK OF THE WINTER WEATHER ADVISORY BUT
GIVEN IT WILL MOSTLY OCCUR AFTER NIGHTFALL THE ADVISORY WILL BE
ALLOWED TO STAND WITH NO CHANGES.
THE MODELS APPEAR TO HAVE TRENDED NORTH SOMEWHAT FAVORING SHERIDAN
COUNTY AND THE FORECAST CENTROID OF HIGHEST SNOWFALL IS NORTHWEST OF
THE HPC FORECAST.
MEANWHILE THE RAP13 AND THE 06Z NAM ARE TAKING THE
BETTER FOCUS ACROSS THE WRN CHEYENNE DIVIDE AND TOWARD THE HIGHER
TERRAIN NORTH OF SCOTTSBLUFF WHICH IS SOUND. THIS METEOROLOGICAL
WOBBLING WILL LIKELY CONTINUE TODAY. THE LATEST RADAR AND OBS ACROSS
WRN SD INDICATE SNOW IS NOW UNDERWAY...ABOUT 5 HOURS SOONER THAN
FORECAST WHICH SUPPORTS THE OFFICIAL FORECAST. THE NAM MODEL SHOWS
FORCING ACROSS NW NEB THIS EVENING AROUND 03Z WHICH LIFTS EAST INTO
ERN SD BY 06Z. THE RAP WEAKENS THIS DISTURBANCE VERY QUICKLY AND
RAPIDLY SETS UP A CLOSED H700MB LOW NEAR CHEYENNE. THERE IS WOBBLING
IN THE MODELS BUT THIS IS NORMAL AND THE FORECAST FOLLOWS THE MODEL
CONSENSUS.
SATELLITE WATER VAPOR SHOWS A VIGOROUS UPPER LOW DROPPING THROUGH
THE CNTL ROCKIES THIS MORNING. THIS STORM IS BEING FUELED BY A HIGH
QUALITY SUBTROPICAL RIVER OF MOISTURE OFF OF HAWAII SUGGESTING THERE
COULD BE ROOM FOR SURPRISE SNOWFALL AMOUNTS...SOMEWHERE. THE
NATIONAL WEATHER HAZARDS MAP SHOWS AN INCREASE IN WINTER STORM
WARNINGS ACROSS THE CNTL ROCKIES.
THE LATEST WIND FORECAST INDICATES NORTH WINDS AT 15 TO 20 MPH
GUSTING TO NEAR 30 MPH. THIS IS ABOUT 5 MPH LESS THAN THE PREVIOUS
FORECAST. THE 00Z ECM WAS THE ONLY MODEL INDICATING 25 MPH WIND
SPEEDS. BLOWING SNOW IS INCLUDED IN THE FORECAST TONIGHT WHICH IS
CONSISTENT WITH AND WIND SPEEDS APPROACHING 25 MPH.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 404 AM CST THU DEC 25 2014
THIS PORTION OF THE FORECAST BEGINS WITH ONGOING PRECIPITATION
ACROSS WESTERN AND NORTH CENTRAL NEBRASKA ASSOCIATED WITH THE
UPPER LEVEL TROUGH CURRENTLY WITH ITS BASE OVER CENTRAL CALIFORNIA
AND EXTENDING NORTH THROUGH IDAHO. BY 12Z FRIDAY...THE BASE OF THE
TROUGH IS EXPECTED TO HAVE MOVED EAST AND BE OVER ARIZONA.
MEANWHILE...ANOTHER SHORTWAVE TROUGH FROM THE NORTHERN STREAM
WOULD BE MOVING INTO MONTANA.
ON FRIDAY MORNING SNOW OVER NORTHWEST NEBRASKA SHOULD BE WINDING
DOWN AS THE LEAD SHORTWAVE TROUGH THAT WILL MOVE ACROSS THE AREA
TONIGHT MOVES EAST INTO THE UPPER MISSISSIPPI RIVER VALLEY. CROSS
SECTIONS SHOW THE AMOUNT OF LIFT ACROSS THIS AREA DIMINISHING FRIDAY
MORNING...WITH THE DEEP MOISTURE ALSO ON THE WAYSIDE BY 18Z AS DRY
AIR STARTS TO ADVECT INTO NORTHWEST NEBRASKA BEHIND THE SHORTWAVE.
ADDITIONAL SNOW AMOUNTS OVER THE AREAS IN THE WINTER WEATHER
ADVISORY WILL BE MINIMAL ON FRIDAY AND AS WINDS GO DOWN THROUGH THE
DAY...ENDING THE ADVISORY AT 18Z CONTINUES TO LOOK APPROPRIATE.
LOOKING FURTHER SOUTH AND EAST AT 12Z...THE COLUMN ISN/T COMPLETELY
SATURATED AS THE MODELS ARE SHOWING DRY AIR IN THE MID LEVELS...FROM
750MB TO 600MB. SATURATION IS SEEN THOUGH BELOW 750MB BUT THE DRY
LAYER LOOKS TOO DEEP TO PROVIDE A SEEDER/FEEDER PROCESS. THERE IS
INDICATION THAT LIFT IN THIS LAYER INCREASES LATE THURSDAY NIGHT AND
FRIDAY MORNING WHICH COULD INDICATE POTENTIAL FOR FREEZING DRIZZLE
AS NO ICE WOULD BE INTRODUCED INTO THAT LAYER. HOWEVER...THE
MOISTURE QUICKLY INCREASES AFTER 12Z AND WITH LITTLE CONFIDENCE ON
THIS HAVE NO MENTION IN THE FORECAST AT THIS TIME AND HAVE ONLY
SNOW.
THROUGH THE DAY FRIDAY AND SATURDAY...THE UPPER LEVEL TROUGH IS
EXPECTED TO BECOME ELONGATED AS A 120KT-130KT JET SHEARS IT INTO
SEVERAL PIECES. THE MODELS ARE IN GOOD AGREEMENT WITH THIS
OCCURRING....WITH THE FIRST PIECE OF ENERGY MOVING UP THROUGH KANSAS
AND INTO EASTERN NEBRASKA BY SATURDAY MORNING. THEN DURING THE DAY
SATURDAY...THIS SHORTWAVE TROUGH PHASES TOGETHER WITH THE SHORTWAVE
MOVING OUT OF MONTANA ACROSS CENTRAL AND EASTERN NEBRASKA.
SNOW IS EXPECTED TO INCREASE IN COVERAGE AND INTENSITY OVER THE
SOUTHERN PART OF THE FORECAST AREA LATE FRIDAY MORNING AND AFTERNOON
AS LIFT INCREASES DUE TO THE SHORTWAVE TROUGH MOVING THROUGH KANSAS
AND THE EASTERN PART OF NEBRASKA. CURRENT MODELS SHOW THE 8-12
UBAR/S OF OMEGA THROUGH THE DENDRITIC GROWTH ZONE ACROSS SOUTHERN
NEBRASKA WHICH COULD LEAD TO SLIGHTLY HIGHER THAN NORMAL SNOW TO
LIQUID RATIOS /16:1 TO 19:1/. SO...DESPITE QPF AMOUNTS NOT BEING
SIGNIFICANT FRIDAY AND FRIDAY NIGHT /0.10 TO 0.20 INCHES/ COULD GET
UP TO 3 INCHES IN SOME PARTS OF THE AREA BY SATURDAY MORNING. COLD
AIR ADVECTION WILL BE ONGOING THROUGH THE DAY FRIDAY AND WITH CLOUDS
AND SNOW DON/T EXPECT TEMPERATURES TO WARM MUCH. PRIOR FORECAST HAD
HIGHS IN THE UPPER TEENS TO MID 20S WHICH STILL LOOK GOOD AND ONLY
MINOR MODIFICATIONS WERE MADE.
AS THE MONTANA SHORTWAVE PUSHES THROUGH SUBSIDENCE WILL START TO DRY
THINGS OUT OVER NORTHWEST NEBRASKA BY SATURDAY MORNING. NOT ENTIRELY
CONFIDENT ON HOW MUCH CLOUDS WILL REMAIN BY 12Z...BUT IF SKIES DO
CLEAR...WITH A GOOD SNOWPACK ON THE GROUND TEMPERATURES COULD DROP
TO NEAR 0F. HIGH PRESSURE BUILDS INTO THE REGION ON SATURDAY WHICH
WILL BRING AN END TO ALL OF THE SNOW AND ALSO DIMINISH THE WINDS.
TEMPERATURES SHOULD BE A BIT WARMER BUT NOT BY MUCH...WITH HIGHS
LIKELY IN THE 20S.
QUIET CONDITIONS WILL BE SEEN FOR THE REMAINDER OF THE WEEKEND...BUT
ANOTHER STRONG SYSTEM WILL MOVE INTO THE PACIFIC NORTHWEST SATURDAY
NIGHT AND WILL DIG SOUTH INTO THE SOUTHWEST CONUS. THE MODELS ARE IN
DECENT AGREEMENT AND CONTINUE TO BRING SOME VERY COLD AIR DOWN INTO
THE PLAINS BEHIND A COLD FRONT PUSHED BY THIS SYSTEM. THE FRONT
LOOKS TO MOVE SOUTH ACROSS NEBRASKA LATE SUNDAY NIGHT AND MONDAY.
THIS ARCTIC FRONT WILL BRING AN AIRMASS WITH 850MB TEMPERATURES DOWN
AROUND -20C INTO THE AREA /COMPARED TO THE LATEST OBSERVATION AT
KLBF OF 2C/. HIGHS ON TUESDAY COULD BE QUITE COLD...ONLY IN THE
SINGLE DIGITS. THAT BEING SAID...DESPITE THE AGREEMENT IN THE
MODELS...THE GFS ENSEMBLES ARE SHOWING A LARGE DEGREE OF
SPREAD...WITH A STANDARD DEVIATION OF 9 FOR TUESDAY/S HIGHS...WITH A
RANGE FROM 0F TO 42F OVER THE NORTHWEST PART OF THE FORECAST AREA.
BELIEVE THE COLDER ROUTE IS THE WAY TO GO WITH THE AGREEMENT IN A
COLD AIRMASS MOVING IN AND WITH DEEP SNOWPACK TO HELP REDUCE
TEMPERATURE RISES. IN ADDITION...THERE WILL BE CHANCES FOR SNOW
AGAIN EARLY NEXT WEEK BEHIND THE PASSING OF THE ARCTIC FRONT.
NOTHING SIGNIFICANT FOR SNOW AMOUNTS IS EXPECTED AT THIS TIME BUT
WILL CONTINUE TO MONITOR FOR ANY CHANGES.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 526 AM CST THU DEC 25 2014
IFR IN SNOW AND LOW CEILINGS WILL SPREAD SOUTH AND WEST TO NEAR
KVTN-KOGA TODAY. THE SAME FLIGHT RESTRICTIONS WILL CREEP SOUTH TO
NEAR KIML-KLBF-KONL BY 12Z FRIDAY MORNING. OTHERWISE VFR WILL
BECOME MVFR WITH THE PASSAGE OF A COLD FRONT TODAY AND TONIGHT.
THE FRONT IS CURRENTLY MOVING THRU SRN SD.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM NOON CST /11 AM MST/ TODAY TO NOON
CST /11 AM MST/ FRIDAY FOR NEZ004-005-022>024-035-056-094.
&&
$$
SHORT TERM...CDC
LONG TERM...BROOKS
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
404 AM CST THU DEC 25 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 404 AM CST THU DEC 25 2014
THERMAL AND MOISTURE PROFILES LOOK GOOD FOR SNOW ACROSS SHERIDAN
COUNTY. LIFT IS DEEP BUT JUST 5 MICROBARS SUPPORTING THE MODERATE
SNOW FORECAST TOTALS NEAR 5 INCHES BY FRIDAY MORNING...MAINLY
ALONG PINE RIDGE. THE FRONTOGENESIS IS MODEST IN THE NAM. FARTHER
EAST THERE IS EVIDENCE OF A 700MB DRY SLOT NEAR VALENTINE WHICH
WOULD GREATLY LIMIT SNOWFALL. THE FORECAST SHOWS A FAIRLY SHARP
CUTOFF ASSOCIATED WITH THIS DRY INTRUSION. THE SNOWFALL FORECAST
IS MARGINAL ALONG THE ERN FLANK OF THE WINTER WEATHER ADVISORY BUT
GIVEN IT WILL MOSTLY OCCUR AFTER NIGHTFALL THE ADVISORY WILL BE
ALLOWED TO STAND WITH NO CHANGES.
THE MODELS APPEAR TO HAVE TRENDED NORTH SOMEWHAT FAVORING SHERIDAN
COUNTY AND THE FORECAST CENTROID OF HIGHEST SNOWFALL IS NORTHWEST OF
THE HPC FORECAST.
MEANWHILE THE RAP13 AND THE 06Z NAM ARE TAKING THE
BETTER FOCUS ACROSS THE WRN CHEYENNE DIVIDE AND TOWARD THE HIGHER
TERRAIN NORTH OF SCOTTSBLUFF WHICH IS SOUND. THIS METEOROLOGICAL
WOBBLING WILL LIKELY CONTINUE TODAY. THE LATEST RADAR AND OBS ACROSS
WRN SD INDICATE SNOW IS NOW UNDERWAY...ABOUT 5 HOURS SOONER THAN
FORECAST WHICH SUPPORTS THE OFFICIAL FORECAST. THE NAM MODEL SHOWS
FORCING ACROSS NW NEB THIS EVENING AROUND 03Z WHICH LIFTS EAST INTO
ERN SD BY 06Z. THE RAP WEAKENS THIS DISTURBANCE VERY QUICKLY AND
RAPIDLY SETS UP A CLOSED H700MB LOW NEAR CHEYENNE. THERE IS WOBBLING
IN THE MODELS BUT THIS IS NORMAL AND THE FORECAST FOLLOWS THE MODEL
CONSENSUS.
SATELLITE WATER VAPOR SHOWS A VIGOROUS UPPER LOW DROPPING THROUGH
THE CNTL ROCKIES THIS MORNING. THIS STORM IS BEING FUELED BY A HIGH
QUALITY SUBTROPICAL RIVER OF MOISTURE OFF OF HAWAII SUGGESTING THERE
COULD BE ROOM FOR SURPRISE SNOWFALL AMOUNTS...SOMEWHERE. THE
NATIONAL WEATHER HAZARDS MAP SHOWS AN INCREASE IN WINTER STORM
WARNINGS ACROSS THE CNTL ROCKIES.
THE LATEST WIND FORECAST INDICATES NORTH WINDS AT 15 TO 20 MPH
GUSTING TO NEAR 30 MPH. THIS IS ABOUT 5 MPH LESS THAN THE PREVIOUS
FORECAST. THE 00Z ECM WAS THE ONLY MODEL INDICATING 25 MPH WIND
SPEEDS. BLOWING SNOW IS INCLUDED IN THE FORECAST TONIGHT WHICH IS
CONSISTENT WITH AND WIND SPEEDS APPROACHING 25 MPH.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 404 AM CST THU DEC 25 2014
THIS PORTION OF THE FORECAST BEGINS WITH ONGOING PRECIPITATION
ACROSS WESTERN AND NORTH CENTRAL NEBRASKA ASSOCIATED WITH THE
UPPER LEVEL TROUGH CURRENTLY WITH ITS BASE OVER CENTRAL CALIFORNIA
AND EXTENDING NORTH THROUGH IDAHO. BY 12Z FRIDAY...THE BASE OF THE
TROUGH IS EXPECTED TO HAVE MOVED EAST AND BE OVER ARIZONA.
MEANWHILE...ANOTHER SHORTWAVE TROUGH FROM THE NORTHERN STREAM
WOULD BE MOVING INTO MONTANA.
ON FRIDAY MORNING SNOW OVER NORTHWEST NEBRASKA SHOULD BE WINDING
DOWN AS THE LEAD SHORTWAVE TROUGH THAT WILL MOVE ACROSS THE AREA
TONIGHT MOVES EAST INTO THE UPPER MISSISSIPPI RIVER VALLEY. CROSS
SECTIONS SHOW THE AMOUNT OF LIFT ACROSS THIS AREA DIMINISHING FRIDAY
MORNING...WITH THE DEEP MOISTURE ALSO ON THE WAYSIDE BY 18Z AS DRY
AIR STARTS TO ADVECT INTO NORTHWEST NEBRASKA BEHIND THE SHORTWAVE.
ADDITIONAL SNOW AMOUNTS OVER THE AREAS IN THE WINTER WEATHER
ADVISORY WILL BE MINIMAL ON FRIDAY AND AS WINDS GO DOWN THROUGH THE
DAY...ENDING THE ADVISORY AT 18Z CONTINUES TO LOOK APPROPRIATE.
LOOKING FURTHER SOUTH AND EAST AT 12Z...THE COLUMN ISN/T COMPLETELY
SATURATED AS THE MODELS ARE SHOWING DRY AIR IN THE MID LEVELS...FROM
750MB TO 600MB. SATURATION IS SEEN THOUGH BELOW 750MB BUT THE DRY
LAYER LOOKS TOO DEEP TO PROVIDE A SEEDER/FEEDER PROCESS. THERE IS
INDICATION THAT LIFT IN THIS LAYER INCREASES LATE THURSDAY NIGHT AND
FRIDAY MORNING WHICH COULD INDICATE POTENTIAL FOR FREEZING DRIZZLE
AS NO ICE WOULD BE INTRODUCED INTO THAT LAYER. HOWEVER...THE
MOISTURE QUICKLY INCREASES AFTER 12Z AND WITH LITTLE CONFIDENCE ON
THIS HAVE NO MENTION IN THE FORECAST AT THIS TIME AND HAVE ONLY
SNOW.
THROUGH THE DAY FRIDAY AND SATURDAY...THE UPPER LEVEL TROUGH IS
EXPECTED TO BECOME ELONGATED AS A 120KT-130KT JET SHEARS IT INTO
SEVERAL PIECES. THE MODELS ARE IN GOOD AGREEMENT WITH THIS
OCCURRING....WITH THE FIRST PIECE OF ENERGY MOVING UP THROUGH KANSAS
AND INTO EASTERN NEBRASKA BY SATURDAY MORNING. THEN DURING THE DAY
SATURDAY...THIS SHORTWAVE TROUGH PHASES TOGETHER WITH THE SHORTWAVE
MOVING OUT OF MONTANA ACROSS CENTRAL AND EASTERN NEBRASKA.
SNOW IS EXPECTED TO INCREASE IN COVERAGE AND INTENSITY OVER THE
SOUTHERN PART OF THE FORECAST AREA LATE FRIDAY MORNING AND AFTERNOON
AS LIFT INCREASES DUE TO THE SHORTWAVE TROUGH MOVING THROUGH KANSAS
AND THE EASTERN PART OF NEBRASKA. CURRENT MODELS SHOW THE 8-12
UBAR/S OF OMEGA THROUGH THE DENDRITIC GROWTH ZONE ACROSS SOUTHERN
NEBRASKA WHICH COULD LEAD TO SLIGHTLY HIGHER THAN NORMAL SNOW TO
LIQUID RATIOS /16:1 TO 19:1/. SO...DESPITE QPF AMOUNTS NOT BEING
SIGNIFICANT FRIDAY AND FRIDAY NIGHT /0.10 TO 0.20 INCHES/ COULD GET
UP TO 3 INCHES IN SOME PARTS OF THE AREA BY SATURDAY MORNING. COLD
AIR ADVECTION WILL BE ONGOING THROUGH THE DAY FRIDAY AND WITH CLOUDS
AND SNOW DON/T EXPECT TEMPERATURES TO WARM MUCH. PRIOR FORECAST HAD
HIGHS IN THE UPPER TEENS TO MID 20S WHICH STILL LOOK GOOD AND ONLY
MINOR MODIFICATIONS WERE MADE.
AS THE MONTANA SHORTWAVE PUSHES THROUGH SUBSIDENCE WILL START TO DRY
THINGS OUT OVER NORTHWEST NEBRASKA BY SATURDAY MORNING. NOT ENTIRELY
CONFIDENT ON HOW MUCH CLOUDS WILL REMAIN BY 12Z...BUT IF SKIES DO
CLEAR...WITH A GOOD SNOWPACK ON THE GROUND TEMPERATURES COULD DROP
TO NEAR 0F. HIGH PRESSURE BUILDS INTO THE REGION ON SATURDAY WHICH
WILL BRING AN END TO ALL OF THE SNOW AND ALSO DIMINISH THE WINDS.
TEMPERATURES SHOULD BE A BIT WARMER BUT NOT BY MUCH...WITH HIGHS
LIKELY IN THE 20S.
QUIET CONDITIONS WILL BE SEEN FOR THE REMAINDER OF THE WEEKEND...BUT
ANOTHER STRONG SYSTEM WILL MOVE INTO THE PACIFIC NORTHWEST SATURDAY
NIGHT AND WILL DIG SOUTH INTO THE SOUTHWEST CONUS. THE MODELS ARE IN
DECENT AGREEMENT AND CONTINUE TO BRING SOME VERY COLD AIR DOWN INTO
THE PLAINS BEHIND A COLD FRONT PUSHED BY THIS SYSTEM. THE FRONT
LOOKS TO MOVE SOUTH ACROSS NEBRASKA LATE SUNDAY NIGHT AND MONDAY.
THIS ARCTIC FRONT WILL BRING AN AIRMASS WITH 850MB TEMPERATURES DOWN
AROUND -20C INTO THE AREA /COMPARED TO THE LATEST OBSERVATION AT
KLBF OF 2C/. HIGHS ON TUESDAY COULD BE QUITE COLD...ONLY IN THE
SINGLE DIGITS. THAT BEING SAID...DESPITE THE AGREEMENT IN THE
MODELS...THE GFS ENSEMBLES ARE SHOWING A LARGE DEGREE OF
SPREAD...WITH A STANDARD DEVIATION OF 9 FOR TUESDAY/S HIGHS...WITH A
RANGE FROM 0F TO 42F OVER THE NORTHWEST PART OF THE FORECAST AREA.
BELIEVE THE COLDER ROUTE IS THE WAY TO GO WITH THE AGREEMENT IN A
COLD AIRMASS MOVING IN AND WITH DEEP SNOWPACK TO HELP REDUCE
TEMPERATURE RISES. IN ADDITION...THERE WILL BE CHANCES FOR SNOW
AGAIN EARLY NEXT WEEK BEHIND THE PASSING OF THE ARCTIC FRONT.
NOTHING SIGNIFICANT FOR SNOW AMOUNTS IS EXPECTED AT THIS TIME BUT
WILL CONTINUE TO MONITOR FOR ANY CHANGES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1133 PM CST WED DEC 24 2014
FOR THE KLBF TERMINAL...EXPECT BROKEN HIGH CLOUDS RANGING FROM
15000 TO 20000 FT AGL THROUGH 21Z THURSDAY. CIGS WILL LOWER TO
MVFR AFTER 21Z THURSDAY WITH CIGS RANGING FROM 800 TO 1500 FT AGL
BY EVENING. THERE IS A SMALL THREAT FOR SNOW THURSDAY EVENING AND
IT WILL BE HANDLED WITH A PROB 30 GROUP ATTM. FOR THE KVTN
TERMINAL...EXPECT HIGH CLOUDS OVERNIGHT WITH CIGS LOWERING TO 5000
TO 10000 FT AGL THURSDAY MORNING. CIGS WILL LOWER TO 1500 FT AGL
BY EARLY AFTERNOON. LIGHT SNOW IS EXPECTED TO DEVELOP AFTER 21Z
WITH CIGS AROUND 1200 FT AGL AND VISBYS AS LOW AS 2 SM.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM NOON CST /11 AM MST/ TODAY TO NOON
CST /11 AM MST/ FRIDAY FOR NEZ004-005-022>024-035-056-094.
&&
$$
SHORT TERM...CDC
LONG TERM...BROOKS
AVIATION...CLB
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
230 AM EST THU DEC 25 2014
.SYNOPSIS...
A STORM SYSTEM OVER THE EASTERN GREAT LAKES WILL BRING RAIN TO
OUR REGION THROUGH TONIGHT. A COLD FRONT EARLY CHRISTMAS
MORNING WILL BRING RAIN SHOWERS AND EVEN A FEW THUNDERSTORMS WITH
GUSTY WINDS. IT WILL BE WINDY AND CHILLY FOR THE REMAINDER OF
CHRISTMAS DAY WITH A CHANCE OF RAIN AND SNOW SHOWERS. A RIDGE OF
HIGH PRESSURE WILL BRING FAIR WEATHER TO OUR REGION ON FRIDAY.
&&
.NEAR TERM /THROUGH TODAY/...
800 PM EST UPDATE..
UPDATED WIND ADVISORY... WIND ADVISORY NOW IN EFFECT STARTING 1 AM
EST...
RAIN SHOWERS HAVE PRETTY MUCH EXITED THE REGION TO THE EAST AND WE
SHOULD REMAIN IN A LULL FOR THE NEXT FEW HOURS. A COLD FRONT WILL
SURGE ACROSS THE REGION AFTER MIDNIGHT TONIGHT BRINGING AN
ADDITIONAL SHOT OF RAIN SHOWERS. A FEW RUMBLES OF THUNDER WILL BE
POSSIBLE AS THE FROPA MOVES EAST. WE ARE STILL EXPECTING STRONG
WINDS WITH THIS FRONT AND IS MOVING SLIGHTLY MORE QUICKLY THAN
EXPECTED.
COLD FRONT IS ADVANCING QUICKLY TO THE EAST AND IS JUST
CROSSING INTO WESTERN PENNSYLVANIA. EXPECT THIS FRONT TO START TO
IMPACT THE CWA AROUND 06Z IN THE FAR WESTERN EDGES... THUS CHANGED
THE START TIME OF THE WIND ADVISORY FROM 5 TO 1AM. HIGH WINDS WILL
QUICKLY SPREAD EAST DURING THE EARLY MORNING HOURS ON THURS.
LOOKING AT FORECAST SOUNDINGS AND CURRENT OBSERVATIONS... BELIEVE
GUSTS SHOULD REMAIN BELOW 45 KNOTS ACROSS THE CWA WHEN THE FRONT
PASSES THROUGH... DECIDED TO NOT UPGRADE TO A WARNING. WINDS ARE
EXPECTED TO REMAIN STRONG THROUGH MUCH OF DAY TOMORROW. FOR MORE
INFORMATION PLEASE READ PREVIOUS DISCUSSION BELOW.
PREVIOUS FORECAST...
RADARS SHOW PLENTY OF LIGHT RAIN WITH SOME PATCHES OF HEAVIER RAIN
MAINLY ACRS THE ERN 1/2 OF PA AND E OF I-81 IN C NY. THE RAIN WILL
CONT TO TRACK N TO NORTHEASTWARD INTO THE EVENING AND THERE LIKELY
WILL BE A LULL IN THE PRECIPITATION FOR MOST OF OUR AREA BY 00Z
WITH JUST SOME SPOTTY LIGHT RAIN SHOWERS AT BEST. THIS INITIAL
SHOT OF PRECIPITATION WAS ASSOCIATED WITH A SHORT WAVE RIPPLING
NORTHEASTWARD ACRS NY/PA. THIS FEATURE WAS SEEN WELL IN THE 850 MB
WIND FIELDS SHOW A LOW LEVEL WIND MAX ACRS PA AND NY POINTING INTO
THE RIGHT ENTRANCE REGION OF AN UPPER LEVEL JET STREAK OVER OUR
AREA. ONCE THIS LIFTS NE OF THE REGION LATER THIS
AFTERNOON...THERE WILL BE A LULL IN THE PRECIP UNTIL THE COLD
FRONT WHICH WAS PRESENTLY EXTENDED FROM SERN LWR MI TO FAR WRN OH
TO CNTRL KY RACES EASTWARD IN ASSCTN WITH A STRG UPPER LEVEL WAVE
THAT WILL PASS THRU THE REGION LATER TONIGHT. THIS FEATURE WILL BE
THE IMPETUS TO FORCE THIS FRONT THRU BETWEEN 3 AND 9Z ACRS C NY
AND NE PA.
AS THIS UPPER LEVEL FEATURE WORKS E...IT WILL ACCELERATE THE LOW-
LEVEL WINDS TO ARND 60 TO 65 KNOTS AT 850 MB AS PER THE NAM JUST
IN ADVANCE OF THE FRONT. INDEED THE WINDS FROM THE LOWER TO MIDDLE
TROPOSPHERE WILL BE RACING AHEAD OF THIS FRONT LEADING TO
IMPRESSIVE SHEAR PROFILES. THE 0-1 KM SHEAR WAS PROGGED TO BE AT
50 KNOTS...WITH THE 0-3 KM SHEAR AT ABT THE SAME OF 50 KNOTS WITH
THE 0-5 KM SHEAR (MODEL SOUNDINGS ONLY HAVE EQUILIBRIUM LEVELS AT
ABT 5 KM)...OF 75 TO 80 KNOTS. TRADITIONAL 0-6KM SHEAR WHICH MIGHT
NOT APPLY AS MUCH HERE WUD BE ALMOST 100 KNOTS. MAIN PROBLEM IS
HOW UNSTABLE WITH THE LOWER AMS GET IN ADVANCE OF THIS FRNT. THERE
WILL BE INTENSE LL MOISTURE ADVECTION BUT IT WILL BE FAIRLY WARM
ALOFT FOR THIS TIME OF THE YEAR. MODEL SOUNDINGS LOOK ALMOST MOIST
ADIABATIC AHEAD OF FRONT WITH CAPES GENERALLY LESS THAN 100 J/KG.
HIGH RES CONVECTION ALLOWING MODELS INCLUDING THE HRRR (UNTIL 7Z)
AND THE WRF-NMM AND WRF-ARW THRU 12Z THU ARE NOT SHWG ANY
ORGANIZED LINEAR CONVECTION LIKE PREVIOUS RUNS. FOR NOW WILL
CONTINUE MENTION OF THUNDER AND GUSTY WINDS IN FORECASTS AND
MENTION IN HWO AS IT WUD NOT TAKE MUCH TO MIX STRG WINDS DOWN.
EVENING SHIFT WILL HAVE TO MONITOR FOR THE DEVELOPMENT. IF A
SQUALL LINE DOES DEVELOP AND RACES EAST IT CUD SPELL A LOT OF
TROUBLE WITH HIGH WINDS.
AFTER FROPA...GRADIENT WINDS WILL PICK UP AND WE WILL SEE
LINGERING RAIN SHOWERS IN THE BACKLASH MOISTURE ACRS C NY AND NE
PA THU AM. TEMPERATURES WILL SLOWLY FALL AND THE RAIN WILL MIX
WITH SOME SNOW AT TIMES LATER IN THE DAY. WILL CONTINUE WIND
ADVISORIES FOR CHRISTMAS DAY AS WE CAN EASILY SEE WIND GUSTS
BETWEEN 40 AND 50 MPH ACRS OUR NRN 1/2 OF OUR FORECAST AREA MAINLY
N OF BGM AND ELM.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
FOR THURSDAY NIGHT WINDS DIE DOWN AND ANY LINGERING SNSH OFF LAKE
ONTARIO WILL DIE DOWN AS HIGH PRESSURE BUILDS SOUTH OF THE REGION
WITH RIDGING NOSING NORTHWARD. TEMPERATURES WILL REMAIN ABOVE
NORMAL AS OUR AREA REMAINS UNDER A PACIFIC AIRMASS.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
230 AM UPDATE...
AFTER FRONT MVS THRU AREA BY 12Z SUNDAY, PATTERN BCMS MAINLY ZONAL
THRU END OF THE EXTNDD. CANADIAN HIPRES EXPECTED TO DOMINATE WITH
OCNL LK PCPN AND CLDS FILTERING DOWN ON NRLY FLOW. AIRMASS WL BCM
INCREASINGLY COLD THRU THE MIDDLE PART OF THE WEEK. NO MAJOR CHGS
ANTICIPATED TO LONG TERM GRIDS THIS MRNG.
PREV DISCUSSION BLO...
GFS/ECMWF HAVE COME INTO BETTER AGREEMENT WITH THE LATEST MODEL
RUNS... INDICATING A FRONTAL PASSAGE LATE SATURDAY NIGHT THROUGH
SUNDAY FOLLOWED BY A RATHER QUIET EXTENDED FORECAST PERIOD
DOMINATED BY CANADIAN HIGH PRESSURE. SATURDAY WILL FEATURE DRY AND
UNSEASONABLY WARM WEATHER WITH HIGH TEMPERATURES APPROACHING 50 IN
MANY PLACES. A COLD FRONT IS FORECAST TO CROSS THE AREA LATE
SATURDAY NIGHT OR SUNDAY MORNING ACCOMPANIED BY A FEW SHOWERS.
COLDER AIR WILL THEN GRADUALLY FILTER SOUTHEAST ACROSS THE AREA
SUNDAY THROUGH TUESDAY. 850 MB TEMPERATURES ARE FORECAST TO FALL
TO AROUND -10 TO -12 OVER LAKE ONTARIO BY MONDAY BUT THE FLOW WILL
BE STRONGLY ANTICYCLONIC IMPLYING LOTS OF DRY AIR AND LOW
INVERSION HEIGHTS WITH LAKE EFFECT SNOW POTENTIAL AT A MINIMUM.
MEANWHILE A SERIES OF WAVES ARE FORECAST TO TRACK WELL SOUTH OF
OUR AREA WITH PRECIPITATION REMAINING SOUTH OF THE MASON- DIXON
LINE. IF THIS PATTERN IS REALIZED... A COOL MOSTLY DRY PERIOD CAN
BE EXPECTED WITH TEMPERATURES NEAR TO SLIGHTLY BELOW NORMAL.
&&
.AVIATION /08Z THURSDAY THROUGH MONDAY/...
06Z UPDATE...
AREA OF SHOWERS WITH STRONG WIND SHIFT WILL BE AT ELM AND ITH AT
START OF TAF VALID TIME THEN QUICKLY MOVING INTO RME AND AVP BY
07Z. MVFR RESTRICTIONS AS SHOWERS MOVE THROUGH THE AREA TONIGHT.
BEHIND THESE SHOWERS EXPECT TERMINALS WILL STAY MVFR CIGS THROUGH
THE COURSE OF THE DAY BEFORE BECOMING VFR AFTER 20Z FOR ALL SITES
WITH EXCEPTION OF RME. RME SHOULD REMAIN MVFR THROUGH END OF TAF
VALID TIME.
FOR A BRIEF HOUR TONIGHT, EXPECT LLWS AT RME, SYR, BGM AND AVP.
WINDS WILL QUICKLY SHIFT AROUND TO THE SW BY 07Z TONIGHT AT ALL
TERMINALS WITH 15-20KTS SUSTAINED, GUSTING TO 30-35KTS AT TIMES.
OUTLOOK...
FRI/SAT...VFR.
LATE SAT NGT TO SUN...RESTRICTIONS POSSIBLE WITH CHANCE OF RAIN-
SNOW.
SUN NGT/MON...MAINLY VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...WIND ADVISORY UNTIL 7 PM EST THIS EVENING FOR NYZ009-015>018-
022-023-025-036-037-044>046-057.
&&
$$
SYNOPSIS...DJN
NEAR TERM...DJN/KAH
SHORT TERM...DJN
LONG TERM...MSE/PVF
AVIATION...PVF
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1243 AM EST THU DEC 25 2014
.SYNOPSIS...
A STORM SYSTEM OVER THE EASTERN GREAT LAKES WILL BRING RAIN TO
OUR REGION THROUGH TONIGHT. A COLD FRONT EARLY CHRISTMAS
MORNING WILL BRING RAIN SHOWERS AND EVEN A FEW THUNDERSTORMS WITH
GUSTY WINDS. IT WILL BE WINDY AND CHILLY FOR THE REMAINDER OF
CHRISTMAS DAY WITH A CHANCE OF RAIN AND SNOW SHOWERS. A RIDGE OF
HIGH PRESSURE WILL BRING FAIR WEATHER TO OUR REGION ON FRIDAY.
&&
.NEAR TERM /THROUGH TODAY/...
800 PM EST UPDATE..
UPDATED WIND ADVISORY... WIND ADVISORY NOW IN EFFECT STARTING 1 AM
EST...
RAIN SHOWERS HAVE PRETTY MUCH EXITED THE REGION TO THE EAST AND WE
SHOULD REMAIN IN A LULL FOR THE NEXT FEW HOURS. A COLD FRONT WILL
SURGE ACROSS THE REGION AFTER MIDNIGHT TONIGHT BRINGING AN
ADDITIONAL SHOT OF RAIN SHOWERS. A FEW RUMBLES OF THUNDER WILL BE
POSSIBLE AS THE FROPA MOVES EAST. WE ARE STILL EXPECTING STRONG
WINDS WITH THIS FRONT AND IS MOVING SLIGHTLY MORE QUICKLY THAN
EXPECTED.
COLD FRONT IS ADVANCING QUICKLY TO THE EAST AND IS JUST
CROSSING INTO WESTERN PENNSYLVANIA. EXPECT THIS FRONT TO START TO
IMPACT THE CWA AROUND 06Z IN THE FAR WESTERN EDGES... THUS CHANGED
THE START TIME OF THE WIND ADVISORY FROM 5 TO 1AM. HIGH WINDS WILL
QUICKLY SPREAD EAST DURING THE EARLY MORNING HOURS ON THURS.
LOOKING AT FORECAST SOUNDINGS AND CURRENT OBSERVATIONS... BELIEVE
GUSTS SHOULD REMAIN BELOW 45 KNOTS ACROSS THE CWA WHEN THE FRONT
PASSES THROUGH... DECIDED TO NOT UPGRADE TO A WARNING. WINDS ARE
EXPECTED TO REMAIN STRONG THROUGH MUCH OF DAY TOMORROW. FOR MORE
INFORMATION PLEASE READ PREVIOUS DISCUSSION BELOW.
PREVIOUS FORECAST...
RADARS SHOW PLENTY OF LIGHT RAIN WITH SOME PATCHES OF HEAVIER RAIN
MAINLY ACRS THE ERN 1/2 OF PA AND E OF I-81 IN C NY. THE RAIN WILL
CONT TO TRACK N TO NORTHEASTWARD INTO THE EVENING AND THERE LIKELY
WILL BE A LULL IN THE PRECIPITATION FOR MOST OF OUR AREA BY 00Z
WITH JUST SOME SPOTTY LIGHT RAIN SHOWERS AT BEST. THIS INITIAL
SHOT OF PRECIPITATION WAS ASSOCIATED WITH A SHORT WAVE RIPPLING
NORTHEASTWARD ACRS NY/PA. THIS FEATURE WAS SEEN WELL IN THE 850 MB
WIND FIELDS SHOW A LOW LEVEL WIND MAX ACRS PA AND NY POINTING INTO
THE RIGHT ENTRANCE REGION OF AN UPPER LEVEL JET STREAK OVER OUR
AREA. ONCE THIS LIFTS NE OF THE REGION LATER THIS
AFTERNOON...THERE WILL BE A LULL IN THE PRECIP UNTIL THE COLD
FRONT WHICH WAS PRESENTLY EXTENDED FROM SERN LWR MI TO FAR WRN OH
TO CNTRL KY RACES EASTWARD IN ASSCTN WITH A STRG UPPER LEVEL WAVE
THAT WILL PASS THRU THE REGION LATER TONIGHT. THIS FEATURE WILL BE
THE IMPETUS TO FORCE THIS FRONT THRU BETWEEN 3 AND 9Z ACRS C NY
AND NE PA.
AS THIS UPPER LEVEL FEATURE WORKS E...IT WILL ACCELERATE THE LOW-
LEVEL WINDS TO ARND 60 TO 65 KNOTS AT 850 MB AS PER THE NAM JUST
IN ADVANCE OF THE FRONT. INDEED THE WINDS FROM THE LOWER TO MIDDLE
TROPOSPHERE WILL BE RACING AHEAD OF THIS FRONT LEADING TO
IMPRESSIVE SHEAR PROFILES. THE 0-1 KM SHEAR WAS PROGGED TO BE AT
50 KNOTS...WITH THE 0-3 KM SHEAR AT ABT THE SAME OF 50 KNOTS WITH
THE 0-5 KM SHEAR (MODEL SOUNDINGS ONLY HAVE EQUILIBRIUM LEVELS AT
ABT 5 KM)...OF 75 TO 80 KNOTS. TRADITIONAL 0-6KM SHEAR WHICH MIGHT
NOT APPLY AS MUCH HERE WUD BE ALMOST 100 KNOTS. MAIN PROBLEM IS
HOW UNSTABLE WITH THE LOWER AMS GET IN ADVANCE OF THIS FRNT. THERE
WILL BE INTENSE LL MOISTURE ADVECTION BUT IT WILL BE FAIRLY WARM
ALOFT FOR THIS TIME OF THE YEAR. MODEL SOUNDINGS LOOK ALMOST MOIST
ADIABATIC AHEAD OF FRONT WITH CAPES GENERALLY LESS THAN 100 J/KG.
HIGH RES CONVECTION ALLOWING MODELS INCLUDING THE HRRR (UNTIL 7Z)
AND THE WRF-NMM AND WRF-ARW THRU 12Z THU ARE NOT SHWG ANY
ORGANIZED LINEAR CONVECTION LIKE PREVIOUS RUNS. FOR NOW WILL
CONTINUE MENTION OF THUNDER AND GUSTY WINDS IN FORECASTS AND
MENTION IN HWO AS IT WUD NOT TAKE MUCH TO MIX STRG WINDS DOWN.
EVENING SHIFT WILL HAVE TO MONITOR FOR THE DEVELOPMENT. IF A
SQUALL LINE DOES DEVELOP AND RACES EAST IT CUD SPELL A LOT OF
TROUBLE WITH HIGH WINDS.
AFTER FROPA...GRADIENT WINDS WILL PICK UP AND WE WILL SEE
LINGERING RAIN SHOWERS IN THE BACKLASH MOISTURE ACRS C NY AND NE
PA THU AM. TEMPERATURES WILL SLOWLY FALL AND THE RAIN WILL MIX
WITH SOME SNOW AT TIMES LATER IN THE DAY. WILL CONTINUE WIND
ADVISORIES FOR CHRISTMAS DAY AS WE CAN EASILY SEE WIND GUSTS
BETWEEN 40 AND 50 MPH ACRS OUR NRN 1/2 OF OUR FORECAST AREA MAINLY
N OF BGM AND ELM.
&&
.SHORT TERM /TONIGHT THROUGH 6 PM FRIDAY/...
FOR THURSDAY NIGHT WINDS DIE DOWN AND ANY LINGERING SNSH OFF LAKE
ONTARIO WILL DIE DOWN AS HIGH PRESSURE BUILDS SOUTH OF THE REGION
WITH RIDGING NOSING NORTHWARD. TEMPERATURES WILL REMAIN ABOVE
NORMAL AS OUR AREA REMAINS UNDER A PACIFIC AIRMASS.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
GFS/ECMWF HAVE COME INTO BETTER AGREEMENT WITH THE LATEST MODEL
RUNS... INDICATING A FRONTAL PASSAGE LATE SATURDAY NIGHT THROUGH
SUNDAY FOLLOWED BY A RATHER QUIET EXTENDED FORECAST PERIOD
DOMINATED BY CANADIAN HIGH PRESSURE. SATURDAY WILL FEATURE DRY AND
UNSEASONABLY WARM WEATHER WITH HIGH TEMPERATURES APPROACHING 50 IN
MANY PLACES. A COLD FRONT IS FORECAST TO CROSS THE AREA LATE
SATURDAY NIGHT OR SUNDAY MORNING ACCOMPANIED BY A FEW SHOWERS.
COLDER AIR WILL THEN GRADUALLY FILTER SOUTHEAST ACROSS THE AREA
SUNDAY THROUGH TUESDAY. 850 MB TEMPERATURES ARE FORECAST TO FALL
TO AROUND -10 TO -12 OVER LAKE ONTARIO BY MONDAY BUT THE FLOW WILL
BE STRONGLY ANTICYCLONIC IMPLYING LOTS OF DRY AIR AND LOW
INVERSION HEIGHTS WITH LAKE EFFECT SNOW POTENTIAL AT A MINIMUM.
MEANWHILE A SERIES OF WAVES ARE FORECAST TO TRACK WELL SOUTH OF
OUR AREA WITH PRECIPITATION REMAINING SOUTH OF THE MASON-DIXON
LINE. IF THIS PATTERN IS REALIZED... A COOL MOSTLY DRY PERIOD CAN
BE EXPECTED WITH TEMPERATURES NEAR TO SLIGHTLY BELOW NORMAL.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
06Z UPDATE...
AREA OF SHOWERS WITH STRONG WIND SHIFT WILL BE AT ELM AND ITH AT
START OF TAF VALID TIME THEN QUICKLY MOVING INTO RME AND AVP BY
07Z. MVFR RESTRICTIONS AS SHOWERS MOVE THROUGH THE AREA TONIGHT.
BEHIND THESE SHOWERS EXPECT TERMINALS WILL STAY MVFR CIGS THROUGH
THE COURSE OF THE DAY BEFORE BECOMING VFR AFTER 20Z FOR ALL SITES
WITH EXCEPTION OF RME. RME SHOULD REMAIN MVFR THROUGH END OF TAF
VALID TIME.
FOR A BRIEF HOUR TONIGHT, EXPECT LLWS AT RME, SYR, BGM AND AVP.
WINDS WILL QUICKLY SHIFT AROUND TO THE SW BY 07Z TONIGHT AT ALL
TERMINALS WITH 15-20KTS SUSTAINED, GUSTING TO 30-35KTS AT TIMES.
OUTLOOK...
FRI/SAT...VFR.
LATE SAT NGT TO SUN...RESTRICTIONS POSSIBLE WITH CHANCE OF RAIN-
SNOW.
SUN NGT/MON...MAINLY VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...WIND ADVISORY UNTIL 7 PM EST THIS EVENING FOR NYZ009-015>018-
022-023-025-036-037-044>046-057.
&&
$$
SYNOPSIS...DJN
NEAR TERM...DJN/KAH
SHORT TERM...DJN
LONG TERM...JAB/MSE/TAC
AVIATION...PVF
AREA FORECAST DISCUSSION
NWS RALEIGH NC
840 PM EST FRI DEC 26 2014
.SYNOPSIS...HIGH PRESSURE WILL REMAIN OVER THE CAROLINAS THROUGH
SATURDAY... THEN SHIFT OFFSHORE SATURDAY NIGHT. A COLD FRONT WILL
APPROACH FROM THE NORTHWEST ON SUNDAY... AND GRADUALLY MOVE
SOUTHWARD THROUGH THE REGION ON MONDAY.
&&
.NEAR TERM /THROUGH SATURDAY/...
AS OF 840 PM FRIDAY...
ANOTHER QUIET NIGHT WITH BOTH SURFACE HIGH PRESSURE AND MID LEVEL
RIDGING OVERHEAD AND DEEP DRY AND STABLE AIR FROM THE SURFACE UP
THROUGH 500 MB. A SLUG OF HIGHER LEVEL MOISTURE TRACKING AROUND THE
PERIPHERY OF THE RIDGE... NOW MOVING OVER TN/KY/WV/VA... WILL AFFECT
FAR NRN AND NW CWA WITH A PERIOD HIGH THIN CLOUDS... HOWEVER THIS IS
UNLIKELY TO HAVE MUCH IF ANY IMPACT ON TEMPS. WINDS HAVE GONE CALM
IN MOST AREAS... FACILITATING A GOOD TEMP DROP THIS EVENING.
DEWPOINT DEPRESSIONS ARE ALREADY DOWN TO JUST A FEW DEGREES
ESPECIALLY IN THE EAST... WHERE DEWPOINTS ARE GENERALLY HIGHER THAN
IN THE WEST... AND THE LATEST HRRR DEPICTS AREAS OF FOG FORMING
AFTER 09Z ALONG THE I-95 CORRIDOR. HAVE ADDED A MENTION OF FOG IN
THE COASTAL PLAIN LATE TONIGHT INTO SAT MORNING. OTHERWISE... EXPECT
MOSTLY CLEAR SKIES. LOWS 29-36... LOWEST IN OUTLYING AREAS. -GIH
THE HIGH WILL BEGIN TO SLIP OFFSHORE ON SATURDAY AHEAD OF OUR NEXT
SYSTEM. THE AIRMASS WILL UNDERGO FURTHER MODIFICATION AS RETURN FLOW
SETS UP OVER THE REGION. HIGHS SHOULD RISE INTO THE UPPER 50S TO
NEAR 60 DEGREES ACROSS THE NORTHWEST (WHERE MID/HIGH CLOUDS WILL BE
FIRST TO ARRIVE) AND INTO THE LOW/MID 60S FURTHER SOUTHEAST. -KRD
&&
.SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/...
AS OF 305 PM FRIDAY...
SATURDAY NIGHT...SW FLOW ALOFT WILL USHER IN A SERIES OF
DISTURBANCES FROM THE NORTHERN GULF INTO THE SOUTHERN
APPALACHIANS/MID-ATLANTIC REGION. LEAD DISTURBANCE PROJECTED TO
ADVANCE TOWARD OUR REGION LATE SATURDAY NIGHT. MID LEVEL FLOW WILL
GRADUALLY VEER IN RESPONSE TO THIS FEATURE...AIDING IN MOISTURE
TRANSPORT INTO THE REGION. SFC RIDGE IS EXPECTED TO REMAIN ALIGNED
WSW-ENE ACROSS CENTRAL NC...MAINTAINING A DRY AIR PRESENCE. LOW
LEVEL ISENTROPIC LIFT ANEMIC DURING THIS PERIOD SO APPEARS LIFT
GENERATED ALOFT FROM WAA. EXPECT DRY CONDITIONS THROUGH SATURDAY
EVENING WITH PATCHES OF LIGHT RAIN SHOWING UP ON THE RADAR AFTER
MIDNIGHT IN THE WEST. INITIAL PATCHES OF RAIN WILL GO TO MOISTEN THE
SUB CLOUD LAYER. THUS...BEST SHOT OF MEASURABLE RAIN WILL LIKELY BE
CONFINED TO THE FAR WESTERN-SOUTHERN PIEDMONT.
SUNDAY...ATMOSPHERE EXPECTED TO REMAIN ADEQUATELY MOIST TO MAINTAIN
CONSIDERABLE CLOUDINESS. LEAD PERTURBATION EXPECTED TO CROSS JUST
WEST-NW OF OUR REGION IN THE MORNING. BULK OF PRECIP WITH THIS
FEATURE SHOULD OCCUR IN VICINITY OF THE PIEDMONT COUNTIES WITH RAIN
COVERAGE DECREASING TO THE SE. WILL TREND POPS FROM LIKELY NW THIRD
TO CHANCE FAR SE. BY AFTERNOON...EXPECT NOTHING MORE THAN SPOTTY
PRECIP AT THIS TIME WITH CHANCE POPS AREAWIDE. MAX TEMPS SUNDAY
DEPENDENT ON AREAL EXTENT OF RAIN OR SHOWERS. FAVOR BLEND OF MOS
GUIDANCE (UPPER 50S NW TO LOW-MID 60S SE). MORE EXTENSIVE/LONGER
DURATION RAIN WILL RESULT IN COOLER TEMPS BY 3-4 DEGREES.
SUNDAY NIGHT...MODEL GUIDANCE HAS GAINED SOME CONSENSUS ON A
SLIGHTLY MORE PRONOUNCED PERTURBATION AND ATTENDANT SURFACE WAVE TO
AFFECT OUR REGION SUNDAY NIGHT...ESPECIALLY AFTER MIDNIGHT. MAIN
LIFTING MECHANISM APPEARS TO BE FROM A 140+ UPPER JET LIFTING NWD
ACROSS THE NORTHERN MID ATLANTIC...PLACING CENTRAL NC IN THE
FAVORABLE RIGHT ENTRANCE REGION. THIS MAY LEAD TO RAINFALL AMOUNTS
ON THE ORDER OF A HALF INCH OVER THE PIEDMONT. PLAN TO TREND POPS
FROM CHANCE IN THE EVENING TO HIGH LIKELY LATE SUNDAY NIGHT INTO THE
FIRST PART OF MONDAY MORNING. LOWS IN THE MID 40S NW TO LOWER 50S SE.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 325 PM FRIDAY...
MONDAY THROUGH FRIDAY... PERTURBATION ALOFT AND ASSOCIATED SURFACE
WAVE AND FRONT WILL CROSS CENTRAL NC MONDAY MORNING. W-NW FLOW
BEHIND THE EXITING WEATHER SYSTEM MONDAY AFTERNOON-NIGHT WILL LEAD
TO DRIER AND MORE STABLE CONDITIONS. BASED ON CURRENT MODEL
TIMING...FAVOR HIGHEST POPS MONDAY MORNING WITH DECREASING POPS
MONDAY AFTERNOON AND LESS THAN 20 PERCENT POPS BY MONDAY NIGHT.
TEMPS MONDAY DEPENDENT UPON EVENTUAL TRACK OF THE SURFACE LOW. SOME
MODELS FAVOR A TRACK CLOSER TO THE NW PIEDMONT...PLACING BULK OF CWA
IN THE WARM SECTOR. OTHER MODELS CLUSTER AROUND A SOLUTION WITH THE
SFC WAVE CROSSING SC THEN UP ALONG THE NC COAST...PLACING CENTRAL NC
IN THE COOL SECTOR. THE LATER SOLUTION SEEMS MORE LIKELY CONSIDERING
THE POTENTIAL FOR A SHALLOW LAYER OF COOL AIR TO ADVECT INTO THE
REGION BEHIND THE INITIAL PERTURBATION. HAVE TRENDED MAX TEMPS A
LITTLE COOLER THAN MOS GUIDANCE BUT LATER FORECASTS MAY NEED TO
TREND COOLER.
TUESDAY THROUGH FRIDAY WILL FEATURE MAINLY DRY WEATHER WITH A
COOLING TREND AS BROAD UPPER LEVEL TROUGH COVERS THE U.S. THE WLY
FLOW ALOFT AND SFC HIGH PRESSURE DIVING SOUTHWARD ACROSS THE CENTRAL
U.S. NORMALLY SIGNALS DRY AND SEASONABLY COOL CONDITIONS FOR OUR
REGION. MAX TEMPS BY THE NEW YEAR WILL AVERAGE IN THE 40S TO NEAR 50
WITH MIN TEMPS IN THE 20S TO AROUND 30.
&&
.AVIATION /00Z SATURDAY THROUGH TUESDAY/...
AS OF 620 PM FRIDAY...
24-HOUR TAF PERIOD: HIGH CONFIDENCE THAT VFR CONDITIONS WILL PREVAIL
THROUGH THE CURRENT TAF PERIOD. WINDS SHOULD BE CALM TO LIGHT AND
VARIABLE OVERNIGHT AS HIGH PRESSURE BUILDS OVERHEAD. SKIES WILL BE
CLEAR TO PARTLY CLOUDY OVERNIGHT...WITH HIGH CLOUDS BUILDING IN
SATURDAY MORNING...BECOMING SCATTERED TO BROKEN. WINDS WILL BE
LIGHT AND GENERALLY SOUTHWESTERLY ON SATURDAY. -KC
LOOKING AHEAD: EXPECT AN INCREASING POTENTIAL FOR MVFR/IFR CEILINGS
AND RAIN LATE SATURDAY NIGHT THROUGH MONDAY AS A SLOW MOVING FRONT
PROGRESSES ACROSS THE REGION. CONDITIONS ARE EXPECTED TO IMPROVE BY
LATE MONDAY NIGHT INTO TUESDAY. -KRD
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...HARTFIELD/KRD
SHORT TERM...WSS
LONG TERM...WSS
AVIATION...KC/KRD
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1236 AM EST THU DEC 25 2014
.SYNOPSIS...
A COLD FRONT WILL MOVE OFFSHORE BEFORE DAYBREAK THIS MORNING.
SUNSHINE IS EXPECTED TO MAKE A RETURN THIS AFTERNOON AS DRY HIGH
PRESSURE BUILDS INTO THE CAROLINAS TODAY AND FRIDAY...MOVING
OFFSHORE SATURDAY. A COLD FRONT WILL DROP INTO THE SOUTHEAST ON
SUNDAY WITH AREAS OF LOW PRESSURE DEVELOPING MONDAY THROUGH
WEDNESDAY NEXT WEEK...RESULTING IN UNSETTLED WEATHER ACROSS THE
CAROLINAS.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
AS OF 1230 AM THURSDAY...COLD FRONT WILL CROSS THE INTERSTATE 95
CORRIDOR BETWEEN 1 AND 2 AM...AND SHOULD REACH THE COAST BETWEEN 3-5
AM. AN ABRUPT WIND SHIFT IS EXPECTED WITH THE FRONT ALONG WITH COLD
ADVECTION WHICH WILL CONTINUE THROUGH THE DAYLIGHT HOURS LATER
TODAY. CHANGES WITH THIS NEAR-TERM UPDATE FOCUS ON PRECIP COVERAGE
WITH THE FRONT AND HOURLY TEMPERATURES/DEWPOINTS/WINDS. PREVIOUS
DISCUSSION FROM 1000 PM FOLLOWS...
THERE IS NO LONGER A SEVERE WX THREAT ACROSS THE ILM CWA. THE BEST
ORGANIZED CONVECTION IS NOW OVER THE OFFSHORE WATERS PARALLELING THE
CAROLINA COASTLINES FROM OFF CAPE LOOKOUT SOUTHWARD TO OFF CAPE
ROMAIN. THIS ACTIVITY CONTINUES TO PULL FURTHER AWAY FROM THE U.S.
MAINLAND. THIS UPDATE WILL CONCENTRATE ON EVEN FURTHER LOWERING POPS
FROM WEST TO EAST THRUOUT THE REMAINDER OF THE EVENING AND OVERNIGHT
PERIOD. THE COLD FRONT REMAINS SLATED TO PUSH FROM WSW TO ENE ACROSS
THE ILM CWA AND OFF THE COAST DURING THE LATE EVENING HRS THRU THE
PRE-DAWN THU HOURS. LATEST HRRR INDICATES A THIN BAND OF POST
FRONTAL -SHRA TO OCCUR ACROSS THE FA...AND WILL LEAVE IN A LOW
CHANCE POP CHANCE UP TO AROUND OR JUST AFTER DAYBREAK THU. HAVE
RE-TWEAKED HOURLY SFC TEMPS AND DEWPOINTS TO ACCOUNT FOR THE LATEST
TRENDS. HAVE KEPT MORNING MINS BASICALLY THE SAME FROM THE PREVIOUS
730 PM UPDATE. THE LOWS WILL LIKELY OCCUR AT OR 1-2 HRS AFTER
DAYBREAK THU.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
AS OF 334 PM WEDNESDAY...MAIN WEATHER HEADLINE IS THAT SUNSHINE IS
SLATED TO MAKE A DEBUT CHRISTMAS DAY AS SHARP DRYING FOLLOWS A
COLD FRONT SWEEPING OUT TO SEA BY DAYBREAK THURSDAY. HIGH PRESSURE
OF GULF COAST ORIGIN WILL RESULT IN WEAK COOL AIR ADVECTION AND
MAXIMUMS WILL REBOUND SLIGHT ABOVE NORMAL THURSDAY AND FRIDAY FOR
LATE DECEMBER. FRIDAY DAYBREAK LIKELY THE COLDEST TEMPS THIS
PERIOD WITH 30S WIDESPREAD ACROSS THE AREA...CLIMBING 25-28
DEGREES F BY AFTERNOON INTO THE LOW AND MIDDLE 60S UNDER SUNSHINE
AND A FEW STRANDS OF CIRRUS.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 330 AM WEDNESDAY...BEGINNING OF THE WEEKEND PLEASANT BUT
HEIGHT FALLS AND AN APPROACHING COLD FRONT INTO SUNDAY WILL BRING
CLOUDS AND AN INCREASING CHANCE OF RAIN INTO SUNDAY NIGHT.
INDICATIONS ARE THE FRONT MAY STALL OVER OR NEAR THE FORECAST AREA
MONDAY THROUGH MID-WEEK...ALLOWING FOR UNSETTLED WEATHER AS A
SERIES OF WAVES TRAVEL ALONG THE STALLED BOUNDARY. BY DAYS 6/7
TUESDAY AND WEDNESDAY...A COLD FRONT LOOKS TO BRING COOLING AND
UNDERCUTS THE SW FLOW ALOFT. THIS MAY LEAD TO MURKY CONDITIONS
AND MULTIPLE CHANCES OF RAIN/SHOWERS.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
AS OF 06Z...A COLD FRONT MOVING EASTWARD WILL REACH FLO AROUND
0600Z...LBT AROUND 0700Z...MYR AND CRE AROUND 0800Z...AND ILM AROUND
0930Z. SOME LOW CLOUDS CONTINUE TO AFFECT THE COAST WITH CEILINGS
POTENTIALLY BELOW 1000 FEET AT CRE AND ILM FOR THE NEXT COUPLE OF
HOURS. THIS THREAT SHOULD END WITH THE FRONTAL PASSAGE. EXPECT SW
WINDS TO TURN WEST WITH AN HOUR OR TWO OF GUSTS TO 20 KT AS COLDER
AIR PUNCHES IN BEHIND THE FRONT. MAINLY LIGHT SHOWERS NEAR THE
BOUNDARY SHOULD CLEAR OUT WITHIN 1 HR OF THE FRONTAL PASSAGE.
BY DAYBREAK A MID-LEVEL CLOUD CEILING WILL REMAIN...BUT EVEN THIS
SHOULD PUSH OFFSHORE BY LATE MORNING OR EARLY AFTERNOON WITH VFR
CONDITIONS EXPECTED.
EXTENDED OUTLOOK...VFR THURSDAY THROUGH SATURDAY. RAIN RETURNING
SUNDAY AND POSSIBLY MONDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1230 AM THURSDAY...CHANGES TO THE NEAR-TERM PORTION OF THE
COASTAL WATERS FORECAST FOCUS ON THE COLD FRONT WHICH WILL REACH THE
SC COAST AROUND 3 AM...AND THE NC COAST BETWEEN 330 AM AND 500 AM.
AS THE FRONT ITSELF MOVES ACROSS WINDS WILL ABRUPTLY SHIFT FROM SW
TO W WITH GUSTS POTENTIALLY REACHING 30 KNOTS. OTHER FORECAST
ELEMENTS REMAIN LARGELY UNCHANGED. PREVIOUS DISCUSSION FROM 1000 PM
FOLLOWS...
BASED ON LATEST BUOY OBS...WINDS AND SEAS TRENDS ACROSS THE ILM
WATERS HAVE BASICALLY PEAKED DURING THE AFTERNOON HRS...AND ARE NOW
HOLDING MORE OR LESS STEADY. DO EXPECT ANOTHER TEMPORARY INCREASE IN
WINDS AND RESULTANT SEAS DURING THE PRE-DAWN THU HRS...LEADING UP TO
A FEW HRS AFTER DAYBREAK. BASICALLY JUST AHEAD AND IMMEDIATELY AFTER
THE CFP. AS FOR ACTUAL WIND DIRECTIONS AND SPEEDS...WIND DIRECTIONS
WILL VEER FROM THE CURRENT SW DIRECTION...TO WESTERLY LATE TONIGHT
INTO DAYLIGHT THU. A TIGHTENED SFC PG WILL YIELD SPEEDS BETWEEN 15
TO 25 KT...WITH A FEW GUSTS TO 30 KT POSSIBLE LEADING UP TO AND JUST
AFTER THE CFP. SIGNIFICANT SEAS WILL HOLD RELATIVELY STEADY IN THE 5
TO 8 FT RANGE OVERNIGHT...HIGHEST ACROSS THE LOCAL WATERS BETWEEN
CAPE FEAR TO LITTLE RIVER INLET. AVERAGE PERIODS WILL RUN 5.0 TO 6.0
SECONDS.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 330 PM WEDNESDAY...MODERATE WINDS THURSDAY WILL EASE AND
TURN NW LATER IN THE DAY. RESIDUAL WAVE ENERGY WILL TAKE MORNING
TO SETTLE AND RECOVER...AND THE ADVISORY MAY NEED TO RUN THROUGH
MOST IF NOT ALL OF MORNING. THURSDAY ANY STORMS WILL BE CONFINED
TO THE GULF STREAM AND POINTS FARTHER TO SEA. LIGHT WINDS FRIDAY
AND PLEASANT AS SURFACE HIGH PRESSURE MOVES NEARLY OVERHEAD OR JUST
NORTH OF THE AREA. WINDS FRIDAY 10 KT OR LESS FROM NE-ESE.
LONG TERM /SATURDAY THROUGH MONDAY/...
AS OF 330 PM WEDNESDAY...SATURDAY FEATURES A SURFACE HIGH
MIGRATING OFFSHORE AND WEAK RETURN WINDS FROM THE S. A COLD FRONT
WILL DROP FROM THE N VERY LATE IN THE PERIOD MONDAY NIGHT AND
BRING INCREASING NE WINDS...ALTHOUGH AT THIS TIME AN ADVISORY MAY
NOT BE NEEDED. RAIN MAY REDUCE VSBYS BELOW 2-3 NM SUNDAY NIGHT
THROUGH MONDAY IN PERIODS OF LIGHT RAIN OR DRIZZLE.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 1 PM EST THURSDAY FOR AMZ250-252-
254-256.
&&
$$
SYNOPSIS...MJC
NEAR TERM...DCH/TRA
SHORT TERM...MJC
LONG TERM...MJC
AVIATION...TRA
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
949 PM CST FRI DEC 26 2014
.UPDATE...
ISSUED AT 949 PM CST FRI DEC 26 2014
STRATUS HAS REMAINED OVER THE NORTHERN RED RIVER VALLEY AND IS
EVEN SPITTING OUT SOME MORE FLURRIES. MUCH OF THE WESTERN CWA HAS
REMAINED CLEAR AND SOME SPOTS IN THE NORTHWEST HAVE DROPPED DOWN
TO THE -5 TO -10 RANGE. THINK THAT THE COLDEST AREAS COULD BOTTOM
OUT AROUND -10 BUT CLOUDS ARE STARTING TO MOVE IN FROM THE WEST SO
THEY SHOULD SLOWLY START TO RISE AFTER MIDNIGHT. TRIED TO ADJUST
CLOUDS TO REFLECT CURRENT TRENDS AND FOLLOW THE RAP WHICH HAS BEEN
NOT TOO FAR OFF...THE CLEAR AREA MOVING EAST INTO THE VALLEY
TOWARDS MORNING WHILE THE WEST CLOUDS UP AGAIN. EXTENDED THE
FLURRY MENTION...PUTTING ISOLATED OR SCATTERED WHEREVER THE CLOUDS
ARE OVERNIGHT.
UPDATE ISSUED AT 655 PM CST FRI DEC 26 2014
CLOUDS WILL BE THE MAIN ISSUE...AS THE NORTHERN VALLEY HAS SEEN A
BIT MORE CLOUDS MOVING DOWN OUT OF CANADA...BUT THE WEST CONTINUES
TO BE CLEAR. TEMPS JUST NORTH OF LANGDON ARE ALREADY DOWN AROUND
MINUS 8...SO THINK PREVIOUS SHIFTS IDEA OF A SHARP DROP OFF AND
THEN RISING TEMPS LATER ON AS MORE CLOUDS COME IN FROM THE WEST.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 305 PM CST FRI DEC 26 2014
HIGH PRESSURE WILL BUILD INTO THE REGION TONIGHT. CLOUDS HAVE BEEN
SLOW TO CLEAR FROM THE NORTHWEST...BUT THE CLEARING CONTINUES TO
MAKE PROGRESS FROM WEST TO EAST. RAP/HRRR GUIDANCE CLEARS AREAS
ALONG AND WEST OF THE VALLEY BY THIS EVENING...BUT KEEPS AREAS
EAST OF THE VALLEY CLOUDY THROUGH THE OVERNIGHT. TRENDED SLOWER
WITH THE CLEARING EAST OF THE VALLEY...BUT STILL KEPT THE IDEA
FOR CLEARING BY MORNING (LATER UPDATES WILL NEED TO EVALUATE IF
THE HRRR/RAP IDEA MIGHT BE BETTER). MIN TEMPERATURES WILL BE EVEN
TRICKIER...MUCH DEPENDENT ON CLOUD COVER. THERE SHOULD BE A QUICK
DROP THIS EVENING WHERE SKY IS CLEAR...BUT WARM AIR
ADVECTION/RETURN FLOW KICKS IN AFTER MIDNIGHT WHICH SHOULD STEADY
OR SLOWLY RISE TEMPS (AT LEAST FOR THE DVL BASIN...NOT SURE ABOUT
VALLEY LOCATIONS).
COLD FRONT POISED TO DROP THROUGH THE FA SATURDAY NIGHT. ONE LAST
WARMER DAY ON SATURDAY AHEAD OF THIS FEATURE...WITH CLOUDS
INCREASING FROM NORTH TO SOUTH. THIS FROPA WILL BE ASSOCIATED WITH
WEAK FORCING...SO ISOLD SNOW SHOWERS/FLURRIES POSSIBLE. MODELS
INDICATE THAT COLD AIR ADVECTION WILL BE RELATIVELY WEAK...LEADING
TO A SHALLOW MIXING LAYER WITH 15-20 KNOTS AVAILABLE TO MIX
(WINDS MAYBE BREEZY...BUT NOT STRONG).
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 305 PM CST FRI DEC 26 2014
SUNDAY-MONDAY NIGHT...COLD AIR ADVECTION REGIME WITH HIGH
PRESSURE BUILDING INTO THE REGION. TEMPERATURES WILL BE MUCH
COLDER THAN THE PREVIOUS COUPLE WEEKS...WITH MAX TEMPS MAINLY IN
THE SINGLE DIGITS (ABOVE OR BELOW ZERO)...AND MIN TEMPS MAINLY
BELOW ZERO. THE MAIN CONCERN THIS PERIOD WILL BE WIND CHILL
VALUES. THE STRONGEST AREA OF HIGH PRESSURE WILL TRACK ACROSS THE
WESTERN DAKOTAS...KEEPING THIS REGION WITHIN A WEAK SFC PRESSURE
GRADIENT. THIS SHOULD BE ENOUGH FOR WIND SPEEDS AOA 5 KNOTS SUNDAY
NIGHT AND MONDAY NIGHT WHEN TEMPERATURES WILL BE THE COLDEST
(LEADING TO POTENTIAL WIND CHILL ADVISORY CONDITIONS).
TUESDAY-FRIDAY...LONG WAVE RIDGE FORECAST TO REMAIN OVER WESTERN
NORTH AMERICA INTO AK WHILE LONG WAVE TROUGH EXTENDS FROM HUDSON
BAY TO THE DESERT SOUTHWEST. LONG WAVE TROUGH SHIFTS OVER EASTERN
NORTH AMERICA BY THE END OF THE PERIOD. LONG WAVE UPPER RIDGE
DEAMPLIFIES WHILE LONG WAVE TROUGH OVER HUDSON BAY AMPLIFIES
THROUGH THE PERIOD.
ECMWF AND GFS WERE IN GOOD AGREEMENT AT THE BEGINNING OF THE PERIOD.
THE GFS WAS A LITTLE FASTER AND BECOMES FASTER THAN THE ECMWF FOR
THE REST OF THE PERIOD. WILL PREFER THE SLOWER ECMWF.
WILL SPLIT THE DIFFERENCE BETWEEN POPS FROM THIS MORNINGS PACKAGE
AND POPS FOR THIS AFTERNOONS RUN FOR WED NIGHT AND THU.
A COLD DAY TO START ON TUE. SOME MODERATION ON WED AND THU, THEN BACK
INTO ARCTIC AIR ON FRI. HIGH TEMPS WERE GENERALLY INCREASED A DEGREE
OR TWO FOR TUE AND WED, INCREASED ONE TO FOUR DEGREES ON THU AND
LITTLE CHANGE ON FRI.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 655 PM CST FRI DEC 26 2014
STRATUS HAS LINGERED IN THE NORTHERN VALLEY...AND ALTHOUGH KGFK IS
CLEAR IT IS RIGHT ON THE EDGE OF SOME MVFR CIGS. INCLUDED A TEMPO
MENTION OF MVFR CIGS FOR A FEW HOURS AS SOME CLOUDS COULD SLIP IN
BRIEFLY BEFORE MODELS ALL TAKE THE STRATUS EASTWARD. THINK THAT
KDVL...KGFK AND KFAR COULD SEE A PERIOD OF MOSTLY CLEAR SKIES AND
VFR CONDITIONS BEFORE THE NEXT ROUND OF CLOUDS MOVES IN FROM THE
WEST AFTER 06Z. THINK THAT KBJI AND KTVF WILL STAY SOCKED IN WITH
MVFR CIGS THROUGH THE PERIOD. CLOUDS MOVING IN FROM THE WEST
SHOULD PUT CIGS AT ALL TAF SITES IN THE 1200-2500 RANGE BY
TOMORROW NIGHT. WINDS WILL SHIFT AROUND FROM THE NORTHWEST TO THE
SOUTHWEST BUT SHOULD REMAIN BELOW 12 KTS.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...JR
SHORT TERM...TG
LONG TERM...TG/HOPPES
AVIATION...JR
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1154 AM CST THU DEC 25 2014
.UPDATE...
ISSUED AT 1152 AM CST THU DEC 25 2014
LATEST RADAR MOSAIC SHOWS SHALLOW WEAK RETURNS MOVING ACROSS
PARTS OF NORTH DAKOTA. THE HRRR SHOWS THE POTENTIAL FOR FLURRIES
THROUGH THE AFTERNOON...AND THAT IS COVERED IN THE GOING FORECAST.
HAVE A SMALL CONCERN THERE COULD BE LIGHT FREEZING DRIZZLE IN SOME
LOCATIONS..BUT FORECAST SOUNDINGS SHOW TEMPERATURES COLD ENOUGH TO
INTRODUCE ICE INTO THE LOW LEVEL CLOUD LAYER...SO CONTINUE WITH
FLURRIES AT THIS POINT. TEMPERATURES HAVE MAXED OUT IN MOST AREAS
WITH A SLOW DECLINE EXPECTED FOR THE AFTERNOON DUE TO LOW LEVEL
COLD AIR ADVECTION.
UPDATE ISSUED AT 950 AM CST THU DEC 25 2014
LIGHT SNOW CONTINUES TO MOVE SLOWLY SOUTH AND EAST AWAY FROM NORTH
DAKOTA THIS MORNING AS PER REGIONAL RADAR MOSAIC. THE LATEST SHORT
TERM MODELS CONFIRM THE TREND WILL CONTINUE...SO AFTER
COLLABORATION WITH SURROUNDING OFFICES HAVE OPTED TO GO WITH FLURRIES
IN THE FORECAST FOR THE REMAINDER OF TODAY. THE REST OF THE
FORECAST IS IN GOOD SHAPE...ONLY CHANGE WAS TO BLEND IN CURRENT
CONDITIONS.
UPDATE ISSUED AT 634 AM CST THU DEC 25 2014
FORECAST IS ON TRACK. ONLY CHANGES WERE TO BLEND TO LATEST OBS.
LATEST HOURLY OBS SHOWED TEMPS RUNNING A LITTLE HIGHER THAN
FORECAST ACROSS THE NORTH UNDER LOWER CEILINGS. ONLY SEEING A
COUPLE REPORTS OF PRECIPITATION...INCLUDING STANLEY WITH ITS
LATEST OBSERVATION. BOWMAN RADAR CONTINUES TO SHOW RETURNS ACROSS
THE SOUTHWEST WHERE HIGH POPS/LOW QPF ARE ALREADY IN PLACE IN THE
FORECAST WITH A DIMINISHING TREND EARLY THIS MORNING. ANY SNOW
ACCUMULATION IN THAT AREA WILL BE MINIMAL.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 323 AM CST THU DEC 25 2014
THE MAIN CONCERN FOR THE SHORT TERM IS LIGHT SNOW CHANCES ACROSS THE
SOUTHERN TIER OF COUNTIES TODAY.
CURRENTLY...SURFACE LOW PRESSURE WAS CENTERED AT THE BORDER OF
MANITOBA/ONTARIO/MINNESOTA WITH A COLD FRONT EXTENDING WESTWARD
ACROSS NORTH DAKOTA FROM NEAR GRAND FORKS TO BISMARCK TO HETTINGER.
A LARGE LOW LEVEL STRATUS DECK OF CLOUDS WAS BEHIND THE FRONT AND
WAS MOVING SOUTH ACROSS NORTHERN NORTH DAKOTA. THE LOW STRATUS
CLOUDS ARE EXPECTED TO MOVE SOUTH AND REMAIN OVER THE STATE FOR THE
DAYLIGHT HOURS.
ATTENTION TURNS TO SOUTHERN NORTH DAKOTA AND THE SCATTERED AREA OF
LIGHT PRECIPITATION MOVING EAST ALONG THE SOUTH DAKOTA BORDER. THIS
PRECIPITATION IS ASSOCIATED WITH SOME WEAK UPPER LEVEL ENERGY
IMPULSES MOVING EAST IN THE ZONAL FLOW ALOFT. THE ONLY SITE THAT
REPORTED LIGHT SNOW WAS LATE WEDNESDAY EVENING AT OAKES. FARTHER
WEST A LARGER STORM SYSTEM CONTINUES TO DEVELOP...AS THE MAIN UPPER
LEVEL TROUGH OVER THE ROCKIES AT THIS TIME EMERGES INTO THE WESTERN
PLAINS LATER THIS MORNING. THE MODELS CONTINUE TO DEVELOP THIS
SYSTEM FARTHER SOUTH...AND ONLY THE FAR SOUTHWESTERN CORNER OF NORTH
DAKOTA IS FORECAST TO RECEIVE MEASURABLE LIGHT SNOW - NOW LOOKING
LIKE LESS THAN AN INCH OF SNOW IN THE BOWMAN AREA. THUS HAVE LOWERED
PRECIPITATION CHANCES TODAY...THOUGH KEPT CHANCES ALONG THE SOUTH
DAKOTA BORDER THIS MORNING...THEN REDUCED CHANCES TO SLIGHT CHANCE
THIS AFTERNOON.
THUS A CLOUDY CHRISTMAS DAY WITH CHANCES OF LIGHT SNOW IN THE FAR
SOUTHERN TIER OF COUNTIES...AND A CHANCE OF FLURRIES ELSEWHERE.
HIGHS FROM THE LOWER 20S NORTH AND MID TO UPPER 20S SOUTH.
CLEARING FROM NORTHWEST TO SOUTHEAST TONIGHT. LOWS FROM JUST BELOW
ZERO IN THE FAR NORTH CENTRAL TO THE TEENS SOUTH OF JAMESTOWN.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 323 AM CST THU DEC 25 2014
THE EXTENDED PERIOD WILL BE CATEGORIZED BY MOSTLY DRY AND MUCH
COLDER WEATHER. 00Z MODELS AND GEFS IN DECENT AGREEMENT WITH UPPER
LEVEL PATTERN...INITIALLY SHOWING CUTOFF LOW APPROACHING HUDSON
BAY AND BROAD TROUGH OVER NORTH AMERICA. EMBEDDED SHORTWAVE IN
NORTHWEST FLOW ON BACKSIDE OF CUTOFF LOW WILL SUPPORT CHANCE OF
SNOW ACROSS THE NORTH ON SATURDAY AND REINFORCING SHOT OF ARCTIC
AIR. WILL ALSO MAINTAIN LOW POPS FOR MAINLY SOUTHWEST ND ON SUNDAY
AS FRONT PROGRESSES SOUTHWARD. MEANWHILE STRONG SURFACE HIGH
BUILDS SOUTHWARD FROM CANADA WITH 1056MB HIGH CENTERED FROM
MONTANA TO WESTERN ND BY 06Z TUE. SURFACE HIGH TO OUR WEST WILL
SUPPORT NORTHERLY SURFACE WINDS FROM LATE WEEKEND INTO TUESDAY
HELPING WIND CHILLS REACH VERY LOW LEVELS. THE CURRENT FORECAST
SHOWS WIND CHILLS LOWER THAN 25 BELOW ZERO SUNDAY NIGHT MAINLY
NORTH AND EAST OF THE MISSOURI RIVER. MONDAY NIGHT AND TUESDAY
NIGHT SHOULD SEE MAJORITY OF CWA HAVING WIND CHILLS IN 25 BELOW
ZERO TO 30 BELOW RANGE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1152 AM CST THU DEC 25 2014
MVFR CEILINGS WILL PREVAIL AT THE AERODROMES...WITH SOME POTENTIAL
FOR BRIEF IFR. PASSING FLURRIES ARE EXPECTED...THOUGH VISIBILITY
RESTRICTIONS ASSOCIATED WITH THEM SHOULD BE MINOR. CEILINGS ARE
EXPECTED TO IMPROVE TO VFR FROM NORTHWEST TO SOUTHEAST STARTING
LATER TONIGHT...WITH THE TREND CONTINUING INTO FRIDAY MORNING.
WINDS SHOULD GENERALLY BE FROM A NORTHWEST DIRECTION...AND WILL
DECREASE IN SPEED TONIGHT.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...CK
SHORT TERM...JV
LONG TERM...JNS
AVIATION...CK
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1151 PM CST WED DEC 24 2014
.UPDATE...
ISSUED AT 1151 PM CST WED DEC 24 2014
THE RADAR CONTINUES TO SHOW SOME LIGHT RETURNS OVER THE SOUTHERN
COUNTIES...AND THE HRRR IS NOT DOING TOO BAD CAPTURING THIS. ALL
THE SHORT RANGE MODELS HAVE THE WEAK PRECIP IN THE NEXT FEW HOURS
DISSIPATING AND THEN THE NEXT STRONGER SNOW BAND MOVES IN...MAINLY
TO OUR SOUTH. TRIED TO SHOW THAT IN THE GRIDS BY TAPERING POPS
DOWN AND THEN BACK UP. ADJUSTED CLOUDS TO INCLUDE THE CLEARING IN
THE NORTHWEST THAT WILL BE SHORT LIVED.
UPDATE ISSUED AT 949 PM CST WED DEC 24 2014
A FEW RADAR RETURNS HAVE DEVELOPED OVER THE SOUTHWESTERN COUNTIES
OVER THE LAST FEW HOURS. NO REPORTS FROM OBS SITES IN OUR
COUNTIES...BUT WEB CAM AT OAKES SHOWS SOME DECENT LIGHT SNOW
FALLING. INCLUDED SOME MEASURABLE POPS IN THE SOUTHWEST ALONG WITH
SCATTERED FLURRIES IN THE REST OF THE FORECAST AREA THAT HAS
CLOUDS. AMOUNTS WILL BE NO MORE THAN A DUSTING. THE CLEAR SKIES
HAVE PERSISTED IN THE DEVILS LAKE BASIN AND HAVE BEEN SPREADING
EAST...BUT SOME STRATUS HAS ALREADY STARTED TO MOVE DOWN OUT OF
CANADA. ADJUSTED CLOUDS TO ACCOUNT FOR THIS AND HAVE THE DROP IN
TEMPS STEADYING OFF AS THE CLOUDS MOVE IN FROM THE NORTH.
UPDATE ISSUED AT 657 PM CST WED DEC 24 2014
SAT LOOP SHOWS SOME CLEARING IN OUR NORTHWESTERN COUNTIES ALONG
THE SFC TROUGH AXIS...ALTHOUGH WITH MORE STRATUS SEEN UPSTREAM DO
NOT THINK THE CLEARING WILL LAST ALL NIGHT. ADJUSTED SKY GRIDS TO
INCLUDE SOME CLEARING FOR A PERIOD THIS EVENING...AND LOWERED
TEMPS A BIT IN THAT AREA. SOME LIGHT SNOW MOVING ACROSS MAINLY THE
NORTHERN CWA...SO KEPT LOW POPS AND A SCATTERED FLURRY MENTION
FURTHER SOUTH.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 330 PM CST WED DEC 24 2014
MAIN 500 MB SHORT WAVE MOVING THROUGH SOUTHERN MANITOBA THIS AFTN
WITH SNOW MOSTLY CONFINED TO WINNIPEG AND POINTS NORTH. RADAR
RETURNS STRONG ENOUGH TO SIGNAL PROBABLY SOME LIGHT SNOW REACHING
THE GROUND IN AREAS SOUTHWARD INTO NE NORTHEAST NORTH DAKOTA TO
DEVILS LAKE. WILL KEEP LOW POPS FOR MEASURABLE IN THE FAR NORTHERN
RRV OVER TO LAKE OF THE WOODS THIS EVENING WITH FLURRIES FURTHER
SOUTH.
OVERNIGHT...SOUTH WINDS AHD OF TROUGH TO LIKELY SATURATE THE LOW
LEVELS FOR SOME PATCHY FREEZING DRIZZLE OR FLURRIES/FOG EAST OF
THE RED RIVER VALLEY SO MENTIONED THAT. BY 09Z TROUGH WILL BE IN
THE RED RIVER VALLEY AND MOVE EAST PAST BEMIDJI 12Z-15Z PERIOD.
KEPT FLURRIES AND SOME FZDZ EAST OF THE VALLEY THRU CHRISTMAS
MORNING UNTIL FRONT CLEARS AREA AND A BIT COLDER AIRMASS ARRIVES.
FARTHER SOUTH...MODELS CONTINUE IDEA OF A NARROW BAND OF
FRONTOGENETIC FORCING MOVING EAST THRU NRN SD INTO CNTRL MN VERY
LATE TONIGHT AND INTO CHRISTMAS DAY AND NIGHT. EXPECT SOME LIGHT
SNOW IN THIS BAND BUT FORCING AND MOISTURE FOR ANY SIGNIFICANT
SNOWFALL IS NOT THERE IN OUR AREA WITH ONLY 1 INCH PSBL IN FAR
SOUTHERN GRANT COUNTY MN WITH LIKELY A DUSTING TO A FEW TENTHS
ALONG THE IMMEDIATE SOUTH DAKOTA BORDER EAST TO FERGUS FALLS AND
WADENA.
COLDER AIR WILL ARRIVE THURSDAY OVERNIGHT AND HOPEFUL FOR SOME
CLEARING INTO THE DVL REGION AS COLDER AND DRIER AIRMASS MOVES IN.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 330 PM CST WED DEC 24 2014
FRIDAY WILL SEE COLDER AIR MOVING SOUTHEAST GRADUALLY AND DRIER
AIRMASS MOVING IN. ANY LIGHT SNOW OR FLURRIES IN SOUTHEAST OF A
BDE-DTL LINE WILL END IN THE MORNING. HIGH PRESSURE WILL MOVE IN
FRIDAY NIGHT WITH LOWS A LOT COLDER THAN WE ARE USED TOO LATELY
WITH LOWS -5F TO 10 ABOVE NORTHWEST TO SOUTHEAST. SATURDAY WILL BE
DRY AND FOR A CHANGE SEASONABLY COLD WITH SOME SUNSHINE.
LONG WAVE UPPER LEVEL RIDGE BUILDS OVER THE NORTHEASTERN PACIFIC ON
DAY 4. DOWNSTREAM LONG WAVE TROUGH TO EXTEND FROM HUDSON BAY TO THE
DESERT SOUTHWEST. LONG WAVE TROUGH EXPANDS FARTHER SOUTH AND EAST
THROUGH DAY 8. WHILE LONG WAVE PATTERN IS RELATIVELY STATIC, THE
UPPER AIR PATTERN IS MODERATELY PROGRESSIVE WITH SHORT WAVES MOVING
THROUGH THE FLOW.
ECMWF AND GFS WERE IN REASONABLE AGREEMENT AT 84 HOURS. HOWEVER THE
ECMWF BECOMES THE FASTER SOLUTION AT THE BEGINNING, THEN THE GFS
BECOMES THE FASTER SOLUTION AFTER TUE. WILL BLEND THE TWO MODELS.
WILL ADD LOW POPS IN THE SOUTHERN ZONES FOR SUN WITH FRONTAL
BOUNDARY MOVING THROUGH.
HIGH TEMPS WERE DECREASED ONE TO FIVE DEGREES ON SUN, DECREASED A
DEGREE OR SO FOR MON AND TUE, AND INCREASED FOUR TO ELEVEN DEGREES
ON WED FROM THIS MORNINGS FORECAST PACKAGE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1151 PM CST WED DEC 24 2014
KDVL REMAINS VFR WITH THE DRY AIR REDUCING STRATUS...BUT GIVING
THE STRATUS ON SATELLITE ALREADY MOVING DOWN INTO TOWNER COUNTY TO
THE NORTH IT WILL BE VERY SHORT LIVED. JUDGING BY SAT TRENDS THINK
THAT KGFK AND KFAR COULD GO VFR FOR A SHORT PERIOD IN THE NEXT FEW
HOURS BUT THEN GO BACK DOWN TO MVFR AND IFR AS MORE STRATUS MOVES
IN FROM THE NORTH. NOT SO SURE KBJI AND KTVF WILL SEE MUCH
CLEARING...ALTHOUGH KBJI HAS 5000 FT CEILINGS AT THE CURRENT TIME.
THINK THAT TOWARDS MORNING THERE WILL BE MORE IFR CIGS...AND ANY
SNOW WILL STAY SOUTH OF THE TAF SITES. THERE SHOULD BE SOME
IMPROVEMENT TO MVFR TOWARDS AFTERNOON. WINDS WILL SHIFT TO THE
NORTHWEST AT AROUND 8 TO 12 KTS.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...JR
SHORT TERM...RIDDLE
LONG TERM...HOPPES/RIDDLE
AVIATION...JR
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
954 AM EST THU DEC 25 2014
.SYNOPSIS...
LOW PRESSURE WILL BE PULLING NORTHEAST FROM ONTARIO INTO QUEBEC
TODAY. MEANWHILE HIGH PRESSURE WILL BUILD ACROSS THE OHIO AND
TENNESSEE VALLEYS. THIS WILL SHIFT EAST EARLY SATURDAY AND ALLOW A
COLD FRONT TO CROSS NORTHERN OHIO/PA SATURDAY EVENING. HIGH
PRESSURE RETURNS IN ITS WAKE FOR EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A FEW RAIN SHOWERS/DRIZZLE LOCATED ACROSS THE REGION...MAINLY FROM
THE CENTRAL HIGHLANDS EASTWARD INTO NW PA. CANT COMPLETELY RULE
OUT A FEW SNOW FLAKES BUT IT WONT BE MUCH. OTHERWISE IT LOOKS LIKE
WE MAY ATTEMPT TO SEE A FEW BREAKS OF CLOUDS FOR THE AFTERNOON.
PREVIOUS DISCUSSION...
REALLY NOT A LOT OF COLD AIR BEHIND YESTERDAYS COLD FRONT AND THE
MAJORITY OF THE PRECIP ON THE BACKSIDE PULLED UP THROUGH MI AND
INTO CANADA. THEREFORE NO WHITE CHRISTMAS. STILL A FEW RAIN
SHOWERS OUT THERE EARLY THIS MORNING WITH THE UPPER TROUGH. MAY
SEE SOME WET SNOWFLAKES MIX IN AND ALSO MAY JUST SEE SOME PLAIN
DRIZZLE. TEMPERATURES WILL REMAIN ABOVE FREEZING. THE
PRECIPITATION CHANCES REALLY CONFINED TO THIS MORNING AS WE
QUICKLY TRANSITION TO RIDGING AND WARM ADVECTION. HIGHS FOR TODAY
WILL BE PRETTY MUCH WHERE THEY ARE AT RIGHT NOW...UPPER 30S WITH A
FEW IN THE LOWER 40S. MOSTLY CLOUDY...BUT WILL BE OPTIMISTIC FOR
SOME BREAKS ACROSS SOUTHWEST COUNTIES BEFORE SUNSET.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/...
DRY CONDITIONS FOR TONIGHT THROUGH FRIDAY WITH HIGH PRESSURE
BUILDING ACROSS THE OHIO VALLEY. STILL RELATIVELY MILD WITH NO
SOURCE OF COLD AIR WITH THE WEST-SOUTHWEST FLOW. A SHORTWAVE EMERGES
FROM THE ROCKIES LONGWAVE TROUGH FRIDAY NIGHT TOWARD THE GREAT
LAKES REGION. SURFACE LOW PRESSURE WILL TRACK ACROSS THE LAKES
INTO CANADA AND TAKE A COLD FRONT ACROSS OH/PA SATURDAY NIGHT. AS
IT DOES SO...THE FRONT WILL SLOW AND WEAKEN WHILE THE RIDGE ACROSS
THE SOUTHEAST STATES HOLDS AND ONLY FLATTENS WITH TIME. IT WILL
TAKE SOME TIME ON SATURDAY TO BE ABLE TO GET PRECIP INTO NW OHIO.
WILL FOCUS THE MAJORITY OF THE PRECIP CHANCES ON SATURDAY NIGHT.
TEMPERATURES WILL STILL BE MILD SO EXPECTING THE MAJORITY OF THE
PRECIP TO FALL AS RAIN WITH SOME SNOW CHANCES WITH THE ADVANCING
COLD AIR TOWARD SUNDAY MORNING. TEMPERATURES CLOSER TO NORMAL FOR
SUNDAY. WILL LINGER SNOW SHOWER CHANCES INTO SUNDAY BUT HIGH
BUILDING IN MAY END THAT ALL TOGETHER. WILL KEEP CLOUDS AROUND
SUNDAY NIGHT.
&&
.LONG TERM /MONDAY THROUGH WEDNESDAY/...
NEAR TO SLIGHTLY BELOW NORMAL TEMPERATURES FOR THE PERIOD WITH A
RIDGE BUILDING IN FROM THE NORTH. THE MODELS DISAGREE ON THE
MOISTURE. THE GFS IS VERY DRY FOR THE PERIOD WHILE THE ECMWF HAS
MUCH MORE MOISTURE FOR MONDAY THROUGH TUESDAY MORNING. BECAUSE OF
THAT KEPT CHANCE POPS FOR SNOW SHOWERS OVER NE OH AND NW PA AS THE
LAKE AND 850 MB TEMPERATURE DIFFERENCE WILL BE NEAR 16C. AS THE
RIDGE BUILDS IN LATER TUESDAY INTO WEDNESDAY THE FLOW BECOMES
SOUTHWEST SO WENT DRY ACROSS THE ENTIRE FORECAST AREA. WENT A LITTLE
COLDER THAN GUIDANCE MAINLY FOR THE HIGHS BASED ON THE FORECASTED
850 MB TEMPERATURES.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
A RIDGE WILL BE BUILDING INTO THE AREA TODAY. SOME WIDELY
SCATTERED RAIN AND SNOW SHOWERS WILL OCCUR THIS MORNING. OTHERWISE
MVFR CEILINGS WILL SLOWLY RISE. SOME QUESTION ON THE CLEARING FOR
TONIGHT. IT MAKES SENSE WITH THE RIDGE MOVING EAST OF THE AREA.
THE HRRR MODEL KEEPS THE LOW CLOUDS. DELAYED THE CLEARING OF THE
LOW CLOUDS A FEW HOURS...HOWEVER...SOME CIRRUS WILL BE ALOFT.
.OUTLOOK...NON-VFR LATE SATURDAY THROUGH SUNDAY NIGHT AND THEN
MAINLY OVER NE OH AND NW PA MONDAY THROUGH TUESDAY.
&&
.MARINE...
GALE WARNINGS HAVE BEEN DISCONTINUED. WINDS HAVE DIMINISHED BELOW
GALE FORCE ACROSS MUCH OF THE LAKE SO WILL GO AHEAD AND DROP THE
WARNING. WATER LEVELS ON THE WEST END HAVE RISEN ABOVE THE
CRITICAL MARK SO WILL GO AHEAD AND DROP THE LOW WATER ADVISORY.
SINCE WAVES WILL REMAIN WELL ABOVE 4 FEET WILL HOIST AND EXTEND
SMALL CRAFT ADVISORY THROUGH TOMORROW AFTERNOON.
PREVIOUS DISCUSSION...
GALE FORCE WINDS WILL DIMINISH SOMEWHAT QUICKLY FROM THE WEST
TODAY AS WARM ADVECTION WILL BE STARTING AROUND DAYBREAK. WILL
DOWNGRADE THE GALE ON THE WEST END OF THE LAKE TO A SMALL CRAFT
ADVISORY FOR 20 TO 25 KNOT WINDS THROUGH MID AFTERNOON. ON THE
EAST END CONTINUING THE GALE THROUGH 21Z/4PM TODAY AND THEN A
SMALL CRAFT ADVISORY WILL BE NEEDED AFTER THAT. THE FLOW ON THE
LAKE WILL BECOME SOUTHWEST TODAY AS A RIDGE BUILDS INTO THE OHIO
VALLEY. ON FRIDAY SOME QUESTION HOW STRONG THE SOUTHWEST WINDS
WILL BE AND WHETHER A SMALL CRAFT ADVISORY WILL BE
NEEDED...ESPECIALLY ON THE EAST END.
THE WATER LEVEL HAS DROPPED BELOW THE CRITICAL MARK. SOME QUESTION
HOW LOW WILL IT GET WITH THE WINDS NOT THAT STRONG ON THE WEST END.
WILL NOT LET IT DROP BELOW 2 FEET BELOW THE CRITICAL MARK AND
THEN IT SHOULD SLOSH BACK ABOVE THE CRITICAL MARK BY NOON.
A FRONT WILL MOVE ACROSS THE LAKE LATE SATURDAY PROMPTING YET
ANOTHER THREAT FOR A SMALL CRAFT ADVISORY ON THE EAST END. BY SUNDAY
MORNING A RIDGE WILL BE OVER THE LAKE AND THE WINDS WILL DECREASE.
THE RIDGE WILL BE IN CONTROL OF THE WEATHER THROUGH TUESDAY...THUS
NOT EXPECTING THE NEED FOR A SMALL CRAFT ADVISORY.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 1 PM EST FRIDAY FOR LEZ142>149.
&&
$$
SYNOPSIS...OUDEMAN
NEAR TERM...MULLEN/OUDEMAN
SHORT TERM...OUDEMAN
LONG TERM...KIELTYKA
AVIATION...KIELTYKA
MARINE...KIELTYKA/LOMBARDY
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
702 AM EST THU DEC 25 2014
.SYNOPSIS...
LOW PRESSURE WILL BE PULLING NORTHEAST FROM ONTARIO INTO QUEBEC
TODAY. MEANWHILE HIGH PRESSURE WILL BUILD ACROSS THE OHIO AND
TENNESSEE VALLEYS. THIS WILL SHIFT EAST EARLY SATURDAY AND ALLOW A
COLD FRONT TO CROSS NORTHERN OHIO/PA SATURDAY EVENING. HIGH
PRESSURE RETURNS IN ITS WAKE FOR EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
HAVE DROPPED THE REMAINING WIND ADVISORY WITH THE EARLY MORNING
UPDATE. REMAINING GUSTS THIS MORNING TO 40 MPH...BUT STRONGER
GUSTS ARE NO LONGER EXPECTED. EVEN DUNKIRK NY IS DOWN TO 40 KNOTS.
JUST A FEW HOURS AGO THEY STILL WERE GUSTING TO 50 KNOTS. PRESQUE
ISLE IS DOWN TO 30 KNOTS.
REALLY NOT A LOT OF COLD AIR BEHIND YESTERDAYS COLD FRONT AND THE
MAJORITY OF THE PRECIP ON THE BACKSIDE PULLED UP THROUGH MI AND
INTO CANADA. THEREFORE NO WHITE CHRISTMAS. STILL A FEW RAIN
SHOWERS OUT THERE EARLY THIS MORNING WITH THE UPPER TROUGH. MAY
SEE SOME WET SNOWFLAKES MIX IN AND ALSO MAY JUST SEE SOME PLAIN
DRIZZLE. TEMPERATURES WILL REMAIN ABOVE FREEZING. THE
PRECIPITATION CHANCES REALLY CONFINED TO THIS MORNING AS WE
QUICKLY TRANSITION TO RIDGING AND WARM ADVECTION. HIGHS FOR TODAY
WILL BE PRETTY MUCH WHERE THEY ARE AT RIGHT NOW...UPPER 30S WITH A
FEW IN THE LOWER 40S. MOSTLY CLOUDY...BUT WILL BE OPTIMISTIC FOR
SOME BREAKS ACROSS SOUTHWEST COUNTIES BEFORE SUNSET.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/...
DRY CONDITIONS FOR TONIGHT THROUGH FRIDAY WITH HIGH PRESSURE
BUILDING ACROSS THE OHIO VALLEY. STILL RELATIVELY MILD WITH NO
SOURCE OF COLD AIR WITH THE WEST-SOUTHWEST FLOW. A SHORTWAVE EMERGES
FROM THE ROCKIES LONGWAVE TROUGH FRIDAY NIGHT TOWARD THE GREAT
LAKES REGION. SURFACE LOW PRESSURE WILL TRACK ACROSS THE LAKES
INTO CANADA AND TAKE A COLD FRONT ACROSS OH/PA SATURDAY NIGHT. AS
IT DOES SO...THE FRONT WILL SLOW AND WEAKEN WHILE THE RIDGE ACROSS
THE SOUTHEAST STATES HOLDS AND ONLY FLATTENS WITH TIME. IT WILL
TAKE SOME TIME ON SATURDAY TO BE ABLE TO GET PRECIP INTO NW OHIO.
WILL FOCUS THE MAJORITY OF THE PRECIP CHANCES ON SATURDAY NIGHT.
TEMPERATURES WILL STILL BE MILD SO EXPECTING THE MAJORITY OF THE
PRECIP TO FALL AS RAIN WITH SOME SNOW CHANCES WITH THE ADVANCING
COLD AIR TOWARD SUNDAY MORNING. TEMPERATURES CLOSER TO NORMAL FOR
SUNDAY. WILL LINGER SNOW SHOWER CHANCES INTO SUNDAY BUT HIGH
BUILDING IN MAY END THAT ALL TOGETHER. WILL KEEP CLOUDS AROUND
SUNDAY NIGHT.
&&
.LONG TERM /MONDAY THROUGH WEDNESDAY/...
NEAR TO SLIGHTLY BELOW NORMAL TEMPERATURES FOR THE PERIOD WITH A
RIDGE BUILDING IN FROM THE NORTH. THE MODELS DISAGREE ON THE
MOISTURE. THE GFS IS VERY DRY FOR THE PERIOD WHILE THE ECMWF HAS
MUCH MORE MOISTURE FOR MONDAY THROUGH TUESDAY MORNING. BECAUSE OF
THAT KEPT CHANCE POPS FOR SNOW SHOWERS OVER NE OH AND NW PA AS THE
LAKE AND 850 MB TEMPERATURE DIFFERENCE WILL BE NEAR 16C. AS THE
RIDGE BUILDS IN LATER TUESDAY INTO WEDNESDAY THE FLOW BECOMES
SOUTHWEST SO WENT DRY ACROSS THE ENTIRE FORECAST AREA. WENT A LITTLE
COLDER THAN GUIDANCE MAINLY FOR THE HIGHS BASED ON THE FORECASTED
850 MB TEMPERATURES.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
A RIDGE WILL BE BUILDING INTO THE AREA TODAY. SOME WIDELY
SCATTERED RAIN AND SNOW SHOWERS WILL OCCUR THIS MORNING. OTHERWISE
MVFR CEILINGS WILL SLOWLY RISE. SOME QUESTION ON THE CLEARING FOR
TONIGHT. IT MAKES SENSE WITH THE RIDGE MOVING EAST OF THE AREA.
THE HRRR MODEL KEEPS THE LOW CLOUDS. DELAYED THE CLEARING OF THE
LOW CLOUDS A FEW HOURS...HOWEVER...SOME CIRRUS WILL BE ALOFT.
.OUTLOOK...NON-VFR LATE SATURDAY THROUGH SUNDAY NIGHT AND THEN
MAINLY OVER NE OH AND NW PA MONDAY THROUGH TUESDAY.
&&
.MARINE...
GALE FORCE WINDS WILL DIMINISH SOMEWHAT QUICKLY FROM THE WEST TODAY
AS WARM ADVECTION WILL BE STARTING AROUND DAYBREAK. WILL DOWNGRADE
THE GALE ON THE WEST END OF THE LAKE TO A SMALL CRAFT ADVISORY FOR
20 TO 25 KNOT WINDS THROUGH MID AFTERNOON. ON THE EAST END
CONTINUING THE GALE THROUGH 21Z/4PM TODAY AND THEN A SMALL CRAFT
ADVISORY WILL BE NEEDED AFTER THAT. THE FLOW ON THE LAKE WILL BECOME
SOUTHWEST TODAY AS A RIDGE BUILDS INTO THE OHIO VALLEY. ON FRIDAY
SOME QUESTION HOW STRONG THE SOUTHWEST WINDS WILL BE AND WHETHER A
SMALL CRAFT ADVISORY WILL BE NEEDED...ESPECIALLY ON THE EAST END.
THE WATER LEVEL HAS DROPPED BELOW THE CRITICAL MARK. SOME QUESTION
HOW LOW WILL IT GET WITH THE WINDS NOT THAT STRONG ON THE WEST END.
WILL NOT LET IT DROP BELOW 2 FEET BELOW THE CRITICAL MARK AND
THEN IT SHOULD SLOSH BACK ABOVE THE CRITICAL MARK BY NOON.
A FRONT WILL MOVE ACROSS THE LAKE LATE SATURDAY PROMPTING YET
ANOTHER THREAT FOR A SMALL CRAFT ADVISORY ON THE EAST END. BY SUNDAY
MORNING A RIDGE WILL BE OVER THE LAKE AND THE WINDS WILL DECREASE.
THE RIDGE WILL BE IN CONTROL OF THE WEATHER THROUGH TUESDAY...THUS
NOT EXPECTING THE NEED FOR A SMALL CRAFT ADVISORY.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...GALE WARNING UNTIL 4 PM EST THIS AFTERNOON FOR LEZ061-145>149-
165>169.
LOW WATER ADVISORY UNTIL NOON EST TODAY FOR LEZ142>144-162>164.
SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
LEZ142>144.
&&
$$
SYNOPSIS...OUDEMAN
NEAR TERM...OUDEMAN
SHORT TERM...OUDEMAN
LONG TERM...KIELTYKA
AVIATION...KIELTYKA
MARINE...KIELTYKA
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
934 PM CST FRI DEC 26 2014
.UPDATE...
SEE DISCUSSION FOR EVENING UPDATE.
&&
.DISCUSSION...
ONLY MINOR CHANGES TO THE FORECAST THIS EVENING. COLD FRONT IS NOW
PAST LUBBOCK AND IS FORECASTED TO BE AT COLLEGE STATION AROUND 9
AM TOMORROW MORNING. THE FRONT IS THEN FORECASTED TO BE AT HOUSTON
BETWEEN 2 AND 4 PM. A CONVERGENCE ZONE HAS SET UP THIS EVENING
RIGHT AROUND THE COAST UP INTO HARRIS AND LIBERTY COUNTIES. HIGH
RES MODELS HAVE STRUGGLED WITH THIS PRECIP. NEW RAP SEEMS TO BE
CATCHING ON WITH THE CURRENT TRENDS. GENERAL THINKING IS FOR THE
PRECIP TO PUSH TOWARDS THE NORTH AND EXPAND IN COVERAGE AHEAD OF
THE FRONT. NEW 0Z LCH SOUNDING HAS A PRETTY GOOD CAP AROUND 700 MB
SO EXPECT MOST PRECIP TO REMAIN THUNDER FREE OVERNIGHT. GFS AND
NAM SOUNDINGS ERODE THE CAP A BIT AND SUPPORT THUNDER FOR THE
AFTERNOON. BEHIND THE FRONT EXPECT TEMPERATURES TO FALL TOMORROW.
23
&&
.PREV DISCUSSION... /ISSUED 554 PM CST FRI DEC 26 2014/
DISCUSSION...
SEE THE 00Z AVIATION DISCUSSION BELOW.
40
AVIATION...
THE COLD FRONT WAS LOCATED LATE THIS AFTERNOON THROUGH THE PAN
HANDLE. THE LATEST NAM12 BROUGHT THE FRONT THROUGH KCLL AND KUTS
AROUND 13Z FRIDAY MORNING...BUT THEN SLOWS DOWN THE FRONTAL
MOVEMENT DRASTICALLY. IT THEN SHOULD MAKE ITS WAY THROUGH KCXO BY
20Z AND KIAH BY 00Z FRIDAY EVENING. CONDITIONS WILL BE MVFR
STARTING OUT THIS EVENING AND SHOULD LOWER TO IFR AHEAD OF THE
FRONT OVER THE NORTHERN SITES BY 10Z. THE FORECAST TO THE SOUTH
WAS A BIT TOUGHER REGARDING LOWERING BELOW MVFR. MODEL GUIDANCE
WAS VERY AGGRESSIVE IN EVEN GOING TO LIFR. DECIDED TO HOLD OFF
FOR NOW BUT THINK THERE IS A CHANCE IF THE FRONT SLOWS DOWN AS
ADVERTISED BY THE MODEL. SEA FOG MAY BECOME A PROBLEM TOWARD THE
COAST AS WELL SINCE THE DEWPOINTS WERE ALREADY IN THE MID 60S. AS
OF NOW THE FETCH OVER THE COOLER WATERS WAS FAIRLY SHORT. IF THE
WINDS SWITCH MORE TO THE EAST-SOUTHEAST...THE FETCH WILL LENGTHEN
AND SEA FOG MAY BECOME MORE OF A PROBLEM.
THE MODELS WERE ALSO HINTING AT A BREAK IN THE CONDITIONS BEHIND
THE FRONT AT KCLL AND KUTS...BUT THEN RETURN MVFR CONDITIONS BY
MIDDAY. THESE TYPE OF CONDITIONS DID NOT LOOKS VERY LIKELY FROM
KCXO SOUTHWARD BEHIND THE FRONT DUE TO ISENTROPIC LIFT BEHIND THE
FRONT.
40
PREV DISCUSSION... /ISSUED 342 PM CST FRI DEC 26 2014/
DISCUSSION...
AFTERNOON WATER VAPOR IMAGERY AT 3 PM DEPICTED THE NEXT TROUGH
APPROACHING THE REGION OVER THE FOUR CORNERS...WITH AN ASSOCIATED
COLD FRONT PUSHING THROUGH THE TEXAS PANHANDLE AND CENTRAL
OKLAHOMA. MOSTLY CLOUDY TO CLOUDY SKIES ACROSS THE AREA HAVE KEPT
TEMPERATURES GENERALLY IN THE MID 60S TO NEAR 70 THIS
AFTERNOON...AND THIS WARMTH IS SOMETHING WE LIKELY WON/T SEE FOR
THE REMAINDER OF 2014.
FOR TONIGHT... A PREFRONTAL TROUGH MOVING ACROSS SOUTHEAST TEXAS WILL
ALLOW WINDS TO SLACKEN ENOUGH TO ENABLE AT LEAST PATCHY FOG
DEVELOPMENT ACROSS THE AREA. SEA FOG WILL ALSO BE POSSIBLE OVER
THE COASTAL WATERS TONIGHT WITH HIGHER DEW POINT AIR ADVECTING
OVER COOLER SHELF WATERS /WATER TEMPERATURES NEAR 60 DEGREES/.
CONTINUED LIFT AND LOW LEVEL MOISTURE ADVECTION OVERSPREADING THE
REGION WILL PROMOTE AT LEAST INTERMITTENT LIGHT SHOWERS OR DRIZZLE
INTO THE OVERNIGHT HOURS...WITH OVERNIGHT LOWS BOTTOMING OUT IN
THE 60S.
AS THE UPPER TROUGH CONTINUES TO PUSH EAST ON SATURDAY... THE
FRONT MAKING ITS WAY THROUGH THE LONE STAR STATE WILL MOVE INTO
SOUTHEAST TEXAS. ROUGHLY TIMED...THE FRONT WILL REACH COLLEGE
STATION AROUND 8-10 AM... THE HOUSTON METRO 2-4 PM... AND
GALVESTON AROUND 6-8 PM. TEMPERATURES WILL FALL BEHIND THE
FRONT...SO NORTHERN AREAS WILL SEE THEIR HIGHS IN THE MORNING
WHILE SOUTHERN AREAS LOOK TO REALIZE THEIR HIGH TEMPERATURES IN
THE AFTERNOON.
SHOWERS AND THUNDERSTORMS...WITH THE POTENTIAL FOR ISOLATED
STRONG STORMS ALONG THE COAST...WILL BE ALSO POSSIBLE THROUGHOUT
THE DAY SATURDAY AHEAD OF AND ALONG THE COLD FRONT. SEVERAL
INGREDIENTS ARE IN PLACE FOR THUNDERSTORMS BUT THE MAIN QUESTION
WILL BE IF THE INSTABILITY CAN BE REALIZED TO SUPPORT DEVELOPMENT.
GUIDANCE INDICATES THE PRESENCE OF MUCAPE VALUES ALONG THE COAST
1000-1200 J/KG...0-6 KM BULK SHEAR APPROACHING 60-65 KTS...AND
MIDLEVEL LAPSE RATES AROUND 6.5 C/KM...RAISING THE POTENTIAL FOR
MAYBE SMALL HAIL OR SOME GUSTY WINDS FROM THUNDERSTORMS ALONG THE
COAST. FOR NOW THINK THE ATMOSPHERE MAY BE TOO STABLE WITH
FORECAST SOUNDINGS SHOWING THE PRESENCE OF A WEAK CAPPING
INVERSION. BEST CHANCES FOR STRONGER ACTIVITY APPEARS TO BE ALONG
THE FRONT DURING THE AFTERNOON AND EVENING HOURS AS IT APPROACHES
THE UPPER TEXAS COAST.
WEAK OVERRUNNING BEHIND THE FRONT COUPLED WITH ADDITIONAL LIFT
FROM THE PASSING SHORTWAVE TROUGH WILL PROMOTE ISOLATED TO
SCATTERED SHOWERS THROUGHOUT THE DAY ON SUNDAY...WITH BEST
CHANCES CHANCES PRIMARILY EAST OF THE BRAZOS RIVER. COOLER
TEMPERATURES WILL STICK AROUND SUNDAY...BEFORE A BRIEF WARM UP
MONDAY AS WEAK ONSHORE FLOW RESUMES.
IN THE EXTENDED... A STRONG ARCTIC FRONT WILL PUSH ACROSS THE
NORTHERN PLAINS EARLY NEXT WEEK AND REACH SOUTHEAST TEXAS IN THE
TUESDAY/WEDNESDAY TIMEFRAME. SURFACE HIGH PRESSURE BUILDING SOUTH
BEHIND THIS GUIDANCE LOOKS TO BRING A VERY CHILLY END TO 2015. MODEL
GUIDANCE IS OVERLY OPTIMISTIC/WARM WITH MID-WEEK HIGH TEMPERATURES
NEAR 50 GIVEN THE STRENGTH OF THE ARCTIC ANTICYCLONE THAT WILL
SETTLE INTO THE STATE. NAEFS ANOMALIES SHOW THE SURFACE HIGH
PRESSURE CLOSE TO 3 STANDARD DEVIATIONS ABOVE NORMAL /INDICATING A
VERY COLD AIRMASS/ AND FORECAST SOUNDINGS SUPPORT GOING COLDER
THAN GUIDANCE WITH TEMPERATURES IN THE MID 30/S TO LOW 40/S. HOW
COLD TEMPERATURES WILL GET CENTERS AROUND THE ACTUAL PLACEMENT OF
THE SURFACE HIGH...SO FOR NOW WILL CONTINUE TO TREND TEMPERATURES
COLDER /IN THE MID 40S WEDNESDAY AND THURSDAY/ AND ALLOW LATER
SHIFTS TO REFINE. AS ANOTHER TROUGH MOVES ACROSS THE SOUTHERN
PLAINS TOWARDS THE END OF NEXT WEEK...PRECIPITATION CHANCES WILL
INCREASE AGAIN. DESPITE THE COLD AIR IN PLACE...THERMAL PROFILES
SUPPORT A COLD RAIN...AS OPPOSED TO ANY KIND OF WINTRY
PRECIP...IN THE CARDS FOR THE END OF NEXT WEEK.
ALL IN ALL... IT/S LOOKING LIKE A COLD AND POTENTIALLY WET START
TO 2015 FOR SOUTHEAST TEXAS.
HUFFMAN
MARINE...
HAVE EXTENDED SMALL CRAFT ADVISORY FOR COASTAL WATERS
FROM 20 TO 60 NM OFF SHORE UNTIL 9PM TONIGHT AS WINDS AND SEAS HAVE
BEEN SLOW TO SUBSIDE THIS AFTERNOON.
A TIGHTENING PRESSURE GRADIENT COMBINED WITH THE EFFECTS OF A LOW
LEVEL JET HAVE PRODUCED 20 TO 25 KNOT WINDS AND SEAS RUNNING 8 TO 9
FEET AT BUOY 019...LOCATED 60 MILES SOUTH OF FREEPORT. WINDS AND
SEAS ARE STILL EXPECTED TO GRADUALLY DIMINISH TONIGHT/OVERNIGHT AS
THE NEXT COLD FRONT BEGINS TO APPROACH SOUTHEAST TEXAS. IT IS
EXPECTED TO MOVE OFF THE COAST TOMORROW EVENING. WITH A STRONG
ONSHORE FLOW OF WARM/MOIST AIR OVER COOLER WATERS...SEA FOG IS
LIKELY ALONG THE UPPER TEXAS COAST OVER NIGHT AND DURING THE DAY
SATURDAY. 44
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 62 63 42 53 38 / 50 60 40 20 10
HOUSTON (IAH) 65 72 47 53 40 / 50 70 50 40 10
GALVESTON (GLS) 66 70 50 53 48 / 50 70 70 60 10
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT SHOULD EXERCISE CAUTION UNTIL 3 AM CST SATURDAY FOR
THE FOLLOWING ZONES: WATERS FROM FREEPORT TO THE MATAGORDA
SHIP CHANNEL 20 NM TO 60 NM...WATERS FROM HIGH ISLAND TO
FREEPORT 20 TO 60 NM.
&&
$$
DISCUSSION...23
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
1144 AM CST THU DEC 25 2014
.AVIATION...
ONLY AVIATION CONCERN FOR THE FIRST 9 HOURS WILL BE GUSTY WINDS AT
ALL TERMINALS. WIND GUST UP TO 30 KTS WILL BE POSSIBLE WITH BEST
POTENTIAL AT KAUS AND NORTH. WIND DIRECTION WILL BE OUT OF THE
SOUTH GENERALLY AND DIE DOWN TO BELOW 12 KTS BY 00Z TONIGHT.
OVERNIGHT...WINDS WILL SHIFT TO THE SOUTHEAST AND MOISTURE WILL
INCREASE RESULTING IN MVFR/IFR CIG DEVELOPMENT BY EARLY MORNING.
ALSO...MODELS ARE SUGGESTING BELOW 1 SM FOG ALONG THE I35 CORRIDOR
TERMINALS BUT CONFIDENCE IN THE DENSITY OF THE FOG IS LOW DUE TO
THE VERY DRY ATMOSPHERE TODAY. WENT AHEAD AND INCLUDED FOG BUT
KEPT IT AT LOW MVFR CONDITIONS.
&&
.PREV DISCUSSION... /ISSUED 942 AM CST THU DEC 25 2014/
UPDATE...
FORECAST PACKAGE LOOKS ON TRACK FOR TEMPS AND DEWPOINTS. WENT
AHEAD AND UPDATED WIND AND WIND GUST GRIDS WITH LATEST RAP MODEL
AS IT WAS CAPTURING THE GUSTY WINDS ALREADY OBSERVED ON THE
ESCARPMENT AND NORTHERN HILL COUNTRY.
ALSO RE-RAN THE FIRE WX GRIDS USING LATEST MODEL DATA TO ADD SOME
PRECISION TO THE MIN RH VALUES. APPEARS THAT RH VALUES SHOULD STAY
ABOVE 20 PERCENT. WILL CONTINUE TO MONITOR CLOSELY.
TB3
PREV DISCUSSION... /ISSUED 549 AM CST THU DEC 25 2014/
AVIATION...
/12Z TAFS/
VFR CONDITIONS ARE EXPECTED ACROSS AREA SITES THROUGH THIS
EVENING. SURFACE SOUTHERLY WINDS WILL INCREASE LATE THIS MORNING
CONTINUING THROUGH THE AFTERNOON AS MIXING TAKES PLACE AND A
SURFACE TROUGH PUSHES ACROSS NORTHWEST TEXAS. EXPECT GUSTS UP TO
25 KNOTS. LOW LEVEL MOISTURE WILL INCREASE TONIGHT AS SURFACE HIGH
PRESSURE SYSTEM MOVES TO THE EAST. WE ARE ANTICIPATING MVFR
CONDITIONS FOR ALL AREA TERMINALS OVERNIGHT AROUND 09Z AND 11Z
ACROSS KDRT. VFR CONDITIONS SHOULD RETURN BY 18Z FRIDAY.
PREV DISCUSSION... /ISSUED 336 AM CST THU DEC 25 2014/
SHORT TERM (TODAY THROUGH FRIDAY)...
UPPER AIR ANALYSIS LAST EVENING SHOWED A DEEP TROUGH EXTENDING
FROM THE GREAT LAKES TO EAST TEXAS WITH A RIDGE BUILDING UP
THROUGH THE ROCKIES. THERE WAS ANOTHER TROUGH EXTENDING FROM
WASHINGTON TO NORTHERN CALIFORNIA. WATER VAPOR SATELLITE IMAGERY
SHOWED MID-LEVEL DRY AIR OVER SOUTH CENTRAL TEXAS WITH MOISTURE
SPREADING INTO WEST TEXAS. AT THE SURFACE HIGH PRESSURE WAS
CENTERED ALONG THE COAST NEAR SOUTH PADRE ISLAND. THE PRESSURE
GRADIENT WAS NOT WELL DEFINED...BUT WINDS WERE TURNING TO THE WEST
AND SOUTHWEST. THE WEST COAST UPPER TROUGH WILL DIG DOWN INTO THE
SOUTHWEST AND THE UPPER FLOW OVER TEXAS WILL BECOME SOUTHWESTERLY.
BENEATH THIS TROUGH A FRONTAL SYSTEM WILL MOVE INTO WEST TEXAS
REACHING JUST NORTHWEST OF VAL VERDE COUNTY BY THE END OF THE
PERIOD. THE SURFACE HIGH WILL MOVE OUT INTO THE GULF AND LOW LEVEL
WINDS WILL BE SOUTHEASTERLY BRINGING WARM...MOIST AIR TO THE
REGION. THERE MAY BE SUFFICIENT ISENTROPIC LIFT FRIDAY TO PRODUCE
LIGHT RAIN OVER THE EASTERN COUNTIES. OTHERWISE THIS PERIOD WILL
BE WARM AND DRY.
LONG TERM (FRIDAY NIGHT THROUGH WEDNESDAY)...
MODELS SHOW THE UPPER TROUGH CONTINUING TO DIG SOUTH INTO MEXICO
INITIALLY...BUT THEN THERE ARE DIFFERENCES ON WHEN IT KICKS OUT TO
THE EAST. THEY ALL AGREE ON FRONTAL PASSAGE THROUGH OUR CWA FRIDAY
NIGHT AND SATURDAY MORNING. BEST MOISTURE WILL BE OVER THE EASTERN
HALF OF THE AREA...SO THAT IS WHERE THE BEST CHANCES FOR RAIN WILL
BE. MODELS DIFFER ON THE MOVEMENT OF THE UPPER TROUGH ACROSS TEXAS
SUNDAY. THE ECMWF IS FASTEST AND THE CANADIAN IS SLOWEST. WILL
LEAN TOWARD THE GFS WHICH IS IN THE MIDDLE. THIS WILL MEAN
CONTINUED CHANCES FOR RAIN SUNDAY. AFTER THIS TROUGH PASSES THE
UPPER PATTERN WILL BECOME ZONAL FOR THE FIRST PART OF NEXT WEEK
RETURNING DRY WEATHER FOR MONDAY. TUESDAY ANOTHER COLD FRONT WILL
MOVE INTO THE REGION. THIS WILL BRING ANOTHER SLIGHT CHANCE FOR
PRECIPITATION AND COLDER AIR. DEPENDING ON TIMING THERE IS A
CHANCE FOR SOME WINTER TYPE PRECIPITATION TUESDAY NIGHT AND
WEDNESDAY MORNING OVER THE NORTHEASTERN PART OF THE FORECAST AREA.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 63 52 68 55 59 / 0 - 10 20 40
AUSTIN BERGSTROM INTL AIRPORT 63 49 69 56 60 / 0 - 10 20 40
NEW BRAUNFELS MUNI AIRPORT 64 50 70 57 62 / 0 - 10 20 40
BURNET MUNI AIRPORT 60 49 65 49 52 / 0 - 10 20 40
DEL RIO INTL AIRPORT 63 44 65 46 60 / 0 0 - 10 10
GEORGETOWN MUNI AIRPORT 61 51 66 52 54 / 0 - 10 20 40
HONDO MUNI AIRPORT 64 45 68 52 60 / 0 - 10 20 30
SAN MARCOS MUNI AIRPORT 64 50 69 57 61 / 0 - 10 20 40
LA GRANGE - FAYETTE REGIONAL 64 53 71 59 64 / 0 - 20 30 40
SAN ANTONIO INTL AIRPORT 63 51 69 56 61 / 0 - 10 20 40
STINSON MUNI AIRPORT 64 50 70 56 62 / 0 - 10 20 40
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE/AVIATION...03
SYNOPTIC/GRIDS...18
PUBLIC SERVICE/DATA COLLECTION...32
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
942 AM CST THU DEC 25 2014
.UPDATE...
FORECAST PACKAGE LOOKS ON TRACK FOR TEMPS AND DEWPOINTS. WENT
AHEAD AND UPDATED WIND AND WIND GUST GRIDS WITH LATEST RAP MODEL
AS IT WAS CAPTURING THE GUSTY WINDS ALREADY OBSERVED ON THE
ESCARPMENT AND NORTHERN HILL COUNTRY.
ALSO RE-RAN THE FIRE WX GRIDS USING LATEST MODEL DATA TO ADD SOME
PRECISION TO THE MIN RH VALUES. APPEARS THAT RH VALUES SHOULD STAY
ABOVE 20 PERCENT. WILL CONTINUE TO MONITOR CLOSELY.
TB3
&&
.PREV DISCUSSION... /ISSUED 549 AM CST THU DEC 25 2014/
AVIATION...
/12Z TAFS/
VFR CONDITIONS ARE EXPECTED ACROSS AREA SITES THROUGH THIS
EVENING. SURFACE SOUTHERLY WINDS WILL INCREASE LATE THIS MORNING
CONTINUING THROUGH THE AFTERNOON AS MIXING TAKES PLACE AND A
SURFACE TROUGH PUSHES ACROSS NORTHWEST TEXAS. EXPECT GUSTS UP TO
25 KNOTS. LOW LEVEL MOISTURE WILL INCREASE TONIGHT AS SURFACE HIGH
PRESSURE SYSTEM MOVES TO THE EAST. WE ARE ANTICIPATING MVFR
CONDITIONS FOR ALL AREA TERMINALS OVERNIGHT AROUND 09Z AND 11Z
ACROSS KDRT. VFR CONDITIONS SHOULD RETURN BY 18Z FRIDAY.
PREV DISCUSSION... /ISSUED 336 AM CST THU DEC 25 2014/
SHORT TERM (TODAY THROUGH FRIDAY)...
UPPER AIR ANALYSIS LAST EVENING SHOWED A DEEP TROUGH EXTENDING
FROM THE GREAT LAKES TO EAST TEXAS WITH A RIDGE BUILDING UP
THROUGH THE ROCKIES. THERE WAS ANOTHER TROUGH EXTENDING FROM
WASHINGTON TO NORTHERN CALIFORNIA. WATER VAPOR SATELLITE IMAGERY
SHOWED MID-LEVEL DRY AIR OVER SOUTH CENTRAL TEXAS WITH MOISTURE
SPREADING INTO WEST TEXAS. AT THE SURFACE HIGH PRESSURE WAS
CENTERED ALONG THE COAST NEAR SOUTH PADRE ISLAND. THE PRESSURE
GRADIENT WAS NOT WELL DEFINED...BUT WINDS WERE TURNING TO THE WEST
AND SOUTHWEST. THE WEST COAST UPPER TROUGH WILL DIG DOWN INTO THE
SOUTHWEST AND THE UPPER FLOW OVER TEXAS WILL BECOME SOUTHWESTERLY.
BENEATH THIS TROUGH A FRONTAL SYSTEM WILL MOVE INTO WEST TEXAS
REACHING JUST NORTHWEST OF VAL VERDE COUNTY BY THE END OF THE
PERIOD. THE SURFACE HIGH WILL MOVE OUT INTO THE GULF AND LOW LEVEL
WINDS WILL BE SOUTHEASTERLY BRINGING WARM...MOIST AIR TO THE
REGION. THERE MAY BE SUFFICIENT ISENTROPIC LIFT FRIDAY TO PRODUCE
LIGHT RAIN OVER THE EASTERN COUNTIES. OTHERWISE THIS PERIOD WILL
BE WARM AND DRY.
LONG TERM (FRIDAY NIGHT THROUGH WEDNESDAY)...
MODELS SHOW THE UPPER TROUGH CONTINUING TO DIG SOUTH INTO MEXICO
INITIALLY...BUT THEN THERE ARE DIFFERENCES ON WHEN IT KICKS OUT TO
THE EAST. THEY ALL AGREE ON FRONTAL PASSAGE THROUGH OUR CWA FRIDAY
NIGHT AND SATURDAY MORNING. BEST MOISTURE WILL BE OVER THE EASTERN
HALF OF THE AREA...SO THAT IS WHERE THE BEST CHANCES FOR RAIN WILL
BE. MODELS DIFFER ON THE MOVEMENT OF THE UPPER TROUGH ACROSS TEXAS
SUNDAY. THE ECMWF IS FASTEST AND THE CANADIAN IS SLOWEST. WILL
LEAN TOWARD THE GFS WHICH IS IN THE MIDDLE. THIS WILL MEAN
CONTINUED CHANCES FOR RAIN SUNDAY. AFTER THIS TROUGH PASSES THE
UPPER PATTERN WILL BECOME ZONAL FOR THE FIRST PART OF NEXT WEEK
RETURNING DRY WEATHER FOR MONDAY. TUESDAY ANOTHER COLD FRONT WILL
MOVE INTO THE REGION. THIS WILL BRING ANOTHER SLIGHT CHANCE FOR
PRECIPITATION AND COLDER AIR. DEPENDING ON TIMING THERE IS A
CHANCE FOR SOME WINTER TYPE PRECIPITATION TUESDAY NIGHT AND
WEDNESDAY MORNING OVER THE NORTHEASTERN PART OF THE FORECAST AREA.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 63 52 68 55 59 / 0 - 10 20 40
AUSTIN BERGSTROM INTL AIRPORT 63 49 69 56 60 / 0 - 10 20 40
NEW BRAUNFELS MUNI AIRPORT 64 50 70 57 62 / 0 - 10 20 40
BURNET MUNI AIRPORT 60 49 65 49 52 / 0 - 10 20 40
DEL RIO INTL AIRPORT 63 44 65 46 60 / 0 0 - 10 10
GEORGETOWN MUNI AIRPORT 61 51 66 52 54 / 0 - 10 20 40
HONDO MUNI AIRPORT 64 45 68 52 60 / 0 - 10 20 30
SAN MARCOS MUNI AIRPORT 64 50 69 57 61 / 0 - 10 20 40
LA GRANGE - FAYETTE REGIONAL 64 53 71 59 64 / 0 - 20 30 40
SAN ANTONIO INTL AIRPORT 63 51 69 56 61 / 0 - 10 20 40
STINSON MUNI AIRPORT 64 50 70 56 62 / 0 - 10 20 40
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE/AVIATION...03
SYNOPTIC/GRIDS...18
PUBLIC SERVICE/DATA COLLECTION...32
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
618 AM EST THU DEC 25 2014
.SYNOPSIS...
A COLD FRONT WAS MOVING EAST TOWARD THE COAST THIS MORNING. HIGH
PRESSURE OVER THE GULF COAST WILL THEN BUILD ACROSS THE EASTERN
UNITED STATES TODAY AND REMAIN OVER THE REGION THROUGH SATURDAY.
ANOTHER COLD FRONT ARRIVES BY SUNDAY WITH THE NEXT CHANCE OF
PRECIPITATION.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 400 AM EST THURSDAY...
AT 4AM...COLD FRONT WAS JUST EXITING THE FAR EASTERN COUNTIES OF THE
FORECAST AREA. THE WESTERN EDGE OF THE FRONTAL PRECIPITATION
EXTENDED FROM CHARLOTTESVILLE TO DANVILLE. LATEST HRRR HAS THIS
PRECIPITATION EXITING THE EASTERN COUNTY WARNING AREA AROUND
10Z/5AM. WILL KEEP CHANCE OF SHOWERS IN THE WESTERN UPSLOPE AREAS
THIS MORNING. MOISTURE ABOVE 700 MB MOVES OUT OF THE FORECAST AREA
THIS MORNING ALONG WITH THE COLD FRONT. MODELS ERODE THE LOW LEVEL
MOISTURE THIS EVENING. WILL KEEP SOME CLOUD COVER IN THE NORTHWEST
THROUGH THIS EVENING. LOCATIONS TO THE EAST WILL CLEAR OUT THIS
MORNING.
SURFACE HIGH PRESSURE WAS OVER THE GULF COAST. THE HIGH MOVES ACROSS
THE SOUTHEAST UNITED STATES TODAY AND WILL BE CENTERED OVER THE
FORECAST AREA BY FRIDAY MORNING. SURFACE DEW POINTS DROP INTO THE
20S BY LATE TODAY. WITH THE DRY AIR MASS THAT WILL BE IN
PLACE...DIURNAL VARIATION IN TEMPERATURES WILL BE 20 TO 25 DEGREES.
EXPECT VALLEYS TO DECOUPLE THIS EVENING. WILL KEEP LOW TEMPERATURES
AT OR BELOW GUIDANCE TONIGHT.
MSAS SHOWED BEST PRESSURE RISES OVER THE GREAT LAKES EXTENDING INTO
NORTHERN VIRGINIA. 850 WINDS WILL BE AROUND 50 KNOTS FROM THE WEST
EARLY THIS MORNING...BUT WILL STEADILY DIMINISH TO BELOW 20 KNOTS
TONIGHT.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY NIGHT/...
AS OF 300 AM EST THURSDAY...
HIGH PRESSURE WILL KEEP THE REGION DRY THROUGH SATURDAY.
TEMPERATURES WILL MODERATE AS THE CENTER OF THE HIGH SHIFTS EAST AND
INCREASING SOUTHWEST WINDS USHER IN A WARM AIR ADVECTION PATTERN
ACROSS THE REGION.
SATURDAY NIGHT THROUGH SUNDAY NIGHT A BAROCLINIC ZONE WILL ESTABLISH
ITSELF FROM NEAR THE MISSISSIPPI DELTA NORTHEAST INTO THE LOWER OHIO
VALLEY. A SERIES OF DISTURBANCES WILL TRACK ALONG THIS
BOUNDARY AND BRING MULTIPLE PERIODS OF RAIN ACROSS THE FORECAST
AREA. CONFIDENCE IS LOW REGARDING TIMING AND TRACK OF EACH OF THESE
SYSTEMS BASED UPON THE GENEROUS SPREAD IN MODEL SOLUTIONS OF THE
FEATURES. HOWEVER...BY THE DAY SUNDAY...IT IS LIKELY THAT RAIN WILL
OCCUR DURING SOME PERIOD OF THE DAY TIME HOURS...AND LIKEWISE DURING
THE SUNDAY NIGHT PERIOD.
TEMPERATURES WILL BE ABOVE NORMAL DURING THIS PERIOD OF THE FORECAST.
&&
.LONG TERM /MONDAY THROUGH WEDNESDAY/...
AS OF 300 PM EST WEDNESDAY...
LATE WEEKEND INTO MID NEXT WEEK LOOKS TO BE POTENTIALLY UNSETTLED
WITH LARGE SCALE TROUGH OVER THE WESTERN TWO THIRDS OF THE COUNTRY
KICKING SEVERAL SHORT WAVES OUT INTO SOUTHERN APPALACHIAN REGION.
MODELS OFFER SIGNIFICANT DIFFERENCES IN THE STRENGTH AND TIMING OF
THESE WAVES...AND AMOUNT OF GULF MOISTURE THEY ARE ABLE TO TAP.
ALSO RUN-TO-RUN INCONSISTENCIES ARE MAKING THIS OVERALL A RATHER
LOW CONFIDENCE FORECAST. AM CONCERNED THAT THE ECMWF IN PARTICULAR
HAS HAD A TENDENCY TO DIG THE SHORT WAVES A LITTLE TOO MUCH AND
THEN ULTIMATELY DRIVE A DEEPENING SFC WAVE TOO FAR NORTH UP THE
APPALACHIANS OR TO THE WEST OF US. THE FLATTER MORE PROGRESSIVE
GFS HAS BEEN BETTER AS OF LATE. LATEST 12Z ECMWF HAS TRENDED
TOWARD THE MORE SUBDUED GFS FOR THE FIRST SYSTEM HEADED UP OUR WAY
INTO MONDAY...WHILE CANADIAN NOW HAS A MUCH STRONGER SYSTEM
TRACKING JUST TO OUR SOUTH ON MONDAY AND MONDAY NIGHT. WILL LEAN
MORE TOWARD THE WEAKER/FLATTER IDEA ADVERTISED IN THE LATEST GFS
AND NOW ECMWF...AT LEAST THROUGH TUES. ECWMF IS A LITTLE STRONGER
WITH ANOTHER WAVE ON WEDNESDAY...WHILE GFS IS
FASTER...COLDER...AND GENERALLY KEEPS IT SOUTH OF US.
WHILE CONFIDENCE IN THE TIMING AND STRENGTH OF THESE SYSTEMS IS
QUITE LOW RIGHT NOW...THERE IS MORE CLARITY THAT THIS WILL AT THE
VERY LEAST BE A CLOUDY PERIOD...AND THAT LOW LEVEL TEMPS AND
THICKNESSES WILL GENERALLY BE WARM ENOUGH NOT TO HAVE ANY REAL
PRECIP TYPE CONCERNS...WITH THE POSSIBLE EXCEPT OF HIGHEST RIDGES
ACROSS THE FAR NORTH SUNDAY AND MONDAY...WITH ANY SYSTEM ON
WEDNESDAY THERE COULD BE ENOUGH DAMMING SETTING UP THAT
OVERRUNNING COULD BE SOME SORT OF WINTRY MIX...BUT NOT EVEN SURE
WE WILL HAVE PRECIP ON WED. ECMWF WOULD SUGGEST FREEZING RAIN.
THE LARGE SFC HIGH NOSES IN MORE AND MORE AND EACH DAY LOOKS A
LITTLE COOLER THAN THE PREVIOUS ONE WHICH IS REFLECTED IN THE
TEMPERATURE FORECAST. WHILE I HAVE LOWERING POPS EACH
DAY...LARGELY DUE TO INCREASING UNCERTAINTY...AM KEEPING A LOW CHC
TO SLIGHT CHC IN THROUGH THE PERIOD WITH MORE INDICATION OF SOME
WINTRY PRECIP AS WE GET INTO TUES NIGHT AND WED.
OVERALL...FORECAST REALLY REFLECTS A VERY BROAD BRUSH RATHER THAN
GOING EXACTLY WITH ANY ONE SOLUTION...AND EXPECT THERE WILL BE
QUITE A FEW CHANGES TO THE EARLY WEEK FORECAST AS WE GET INTO THE
WEEKEND. NOT MUCH CHANCE FOR A MAJOR STORM DURING THIS
PERIOD...AND AFTER SUNDAY ITS POSSIBLE THAT DRY BUT COOL HIGH
PRESSURE MANAGES TO DOMINATE...BUT BEST GUESS FOR NOW IS SOMETHING
IN BETWEEN. AS ALWAYS...STAY TUNED!
&&
.AVIATION /11Z THURSDAY THROUGH MONDAY/...
AS OF 1125 PM EST WEDNESDAY...
COLD FRONT WAS WELL EAST OF THE REGION THIS MORNING AND RAIN HAS
MOVED OUT OF THE VIRGINIA AND NORTH CAROLINA FOOTHILLS. WINDS WILL
GUST FROM THE WEST UP TO 30 KNOTS BEHIND THE FRONT THIS MORNING.
THIS WILL COMBINE WITH LINGERING LOW LEVEL MOISTURE TO PRODUCE
MVFR CLOUDS IN KBLF AND KLWB AS WELL AS RAIN AND SNOW SHOWERS IN
THE MOUNTAINS.
HIGH PRESSURE OVER THE GULF COAST REGION WILL MOVE INTO THE AREA
TONIGHT...RESULTING IN DIMINISHING WINDS AND UPSLOPE CLOUDS. HIGH
CONFIDENCE THAT RAIN/SNOW SHOWERS WILL DISSIPATE BY 00Z TONIGHT
WITH THE CLOUDS OVER THE MOUNTAINS BECOMING SCATTERED THIS
EVENING. VFR CONDITIONS ARE EXPECTED FRIDAY.
EXTENDED DISCUSSION...
HIGH PRESSURE SHOULD BUILD OVER THE SOUTHEAST...WHICH WILL
PROVIDE VFR WEATHER WITH LIGHTER WINDS THROUGH FRIDAY NIGHT.
ANOTHER COLD FRONT WITH ASSOCIATED LOW PRESSURE WILL APPROACH THE
REGION SATURDAY AND BE OVER OR JUST WEST OF THE AREA SUNDAY. BOUNDARY
MAY LINGER OVER OR JUST SOUTH OF THE REGION EARLY NEXT WEEK WITH
POSSIBLE RETURN TO VFR MONDAY AFTERNOON.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS
NEAR TERM...AMS
SHORT TERM...DS
LONG TERM...SK
AVIATION...AMS/JH
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
407 AM EST THU DEC 25 2014
.SYNOPSIS...
A COLD FRONT WAS MOVING EAST TOWARD THE COAST THIS MORNING. HIGH
PRESSURE OVER THE GULF COAST WILL THEN BUILD ACROSS THE EASTERN
UNITED STATES TODAY AND REMAIN OVER THE REGION THROUGH SATURDAY.
ANOTHER COLD FRONT ARRIVES BY SUNDAY WITH THE NEXT CHANCE OF
PRECIPITATION.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 400 AM EST THURSDAY...
AT 4AM...COLD FRONT WAS JUST EXITING THE FAR EASTERN COUNTIES OF THE
FORECAST AREA. THE WESTERN EDGE OF THE FRONTAL PRECIPITATION
EXTENDED FROM CHARLOTTESVILLE TO DANVILLE. LATEST HRRR HAS THIS
PRECIPITATION EXITING THE EASTERN COUNTY WARNING AREA AROUND
10Z/5AM. WILL KEEP CHANCE OF SHOWERS IN THE WESTERN UPSLOPE AREAS
THIS MORNING. MOISTURE ABOVE 700 MB MOVES OUT OF THE FORECAST AREA
THIS MORNING ALONG WITH THE COLD FRONT. MODELS ERODE THE LOW LEVEL
MOISTURE THIS EVENING. WILL KEEP SOME CLOUD COVER IN THE NORTHWEST
THROUGH THIS EVENING. LOCATIONS TO THE EAST WILL CLEAR OUT THIS
MORNING.
SURFACE HIGH PRESSURE WAS OVER THE GULF COAST. THE HIGH MOVES ACROSS
THE SOUTHEAST UNITED STATES TODAY AND WILL BE CENTERED OVER THE
FORECAST AREA BY FRIDAY MORNING. SURFACE DEW POINTS DROP INTO THE
20S BY LATE TODAY. WITH THE DRY AIR MASS THAT WILL BE IN
PLACE...DIURNAL VARIATION IN TEMPERATURES WILL BE 20 TO 25 DEGREES.
EXPECT VALLEYS TO DECOUPLE THIS EVENING. WILL KEEP LOW TEMPERATURES
AT OR BELOW GUIDANCE TONIGHT.
MSAS SHOWED BEST PRESSURE RISES OVER THE GREAT LAKES EXTENDING INTO
NORTHERN VIRGINIA. 850 WINDS WILL BE AROUND 50 KNOTS FROM THE WEST
EARLY THIS MORNING...BUT WILL STEADILY DIMINISH TO BELOW 20 KNOTS
TONIGHT.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY NIGHT/...
AS OF 300 AM EST THURSDAY...
HIGH PRESSURE WILL KEEP THE REGION DRY THROUGH SATURDAY.
TEMPERATURES WILL MODERATE AS THE CENTER OF THE HIGH SHIFTS EAST AND
INCREASING SOUTHWEST WINDS USHER IN A WARM AIR ADVECTION PATTERN
ACROSS THE REGION.
SATURDAY NIGHT THROUGH SUNDAY NIGHT A BAROCLINIC ZONE WILL ESTABLISH
ITSELF FROM NEAR THE MISSISSIPPI DELTA NORTHEAST INTO THE LOWER OHIO
VALLEY. A SERIES OF DISTURBANCES WILL TRACK ALONG THIS
BOUNDARY AND BRING MULTIPLE PERIODS OF RAIN ACROSS THE FORECAST
AREA. CONFIDENCE IS LOW REGARDING TIMING AND TRACK OF EACH OF THESE
SYSTEMS BASED UPON THE GENEROUS SPREAD IN MODEL SOLUTIONS OF THE
FEATURES. HOWEVER...BY THE DAY SUNDAY...IT IS LIKELY THAT RAIN WILL
OCCUR DURING SOME PERIOD OF THE DAY TIME HOURS...AND LIKEWISE DURING
THE SUNDAY NIGHT PERIOD.
TEMPERATURES WILL BE ABOVE NORMAL DURING THIS PERIOD OF THE FORECAST.
&&
.LONG TERM /MONDAY THROUGH WEDNESDAY/...
AS OF 300 PM EST WEDNESDAY...
LATE WEEKEND INTO MID NEXT WEEK LOOKS TO BE POTENTIALLY UNSETTLED
WITH LARGE SCALE TROUGH OVER THE WESTERN TWO THIRDS OF THE COUNTRY
KICKING SEVERAL SHORT WAVES OUT INTO SOUTHERN APPALACHIAN REGION.
MODELS OFFER SIGNIFICANT DIFFERENCES IN THE STRENGTH AND TIMING OF
THESE WAVES...AND AMOUNT OF GULF MOISTURE THEY ARE ABLE TO TAP.
ALSO RUN-TO-RUN INCONSISTENCIES ARE MAKING THIS OVERALL A RATHER
LOW CONFIDENCE FORECAST. AM CONCERNED THAT THE ECMWF IN PARTICULAR
HAS HAD A TENDENCY TO DIG THE SHORT WAVES A LITTLE TOO MUCH AND
THEN ULTIMATELY DRIVE A DEEPENING SFC WAVE TOO FAR NORTH UP THE
APPALACHIANS OR TO THE WEST OF US. THE FLATTER MORE PROGRESSIVE
GFS HAS BEEN BETTER AS OF LATE. LATEST 12Z ECMWF HAS TRENDED
TOWARD THE MORE SUBDUED GFS FOR THE FIRST SYSTEM HEADED UP OUR WAY
INTO MONDAY...WHILE CANADIAN NOW HAS A MUCH STRONGER SYSTEM
TRACKING JUST TO OUR SOUTH ON MONDAY AND MONDAY NIGHT. WILL LEAN
MORE TOWARD THE WEAKER/FLATTER IDEA ADVERTISED IN THE LATEST GFS
AND NOW ECMWF...AT LEAST THROUGH TUES. ECWMF IS A LITTLE STRONGER
WITH ANOTHER WAVE ON WEDNESDAY...WHILE GFS IS
FASTER...COLDER...AND GENERALLY KEEPS IT SOUTH OF US.
WHILE CONFIDENCE IN THE TIMING AND STRENGTH OF THESE SYSTEMS IS
QUITE LOW RIGHT NOW...THERE IS MORE CLARITY THAT THIS WILL AT THE
VERY LEAST BE A CLOUDY PERIOD...AND THAT LOW LEVEL TEMPS AND
THICKNESSES WILL GENERALLY BE WARM ENOUGH NOT TO HAVE ANY REAL
PRECIP TYPE CONCERNS...WITH THE POSSIBLE EXCEPT OF HIGHEST RIDGES
ACROSS THE FAR NORTH SUNDAY AND MONDAY...WITH ANY SYSTEM ON
WEDNESDAY THERE COULD BE ENOUGH DAMMING SETTING UP THAT
OVERRUNNING COULD BE SOME SORT OF WINTRY MIX...BUT NOT EVEN SURE
WE WILL HAVE PRECIP ON WED. ECMWF WOULD SUGGEST FREEZING RAIN.
THE LARGE SFC HIGH NOSES IN MORE AND MORE AND EACH DAY LOOKS A
LITTLE COOLER THAN THE PREVIOUS ONE WHICH IS REFLECTED IN THE
TEMPERATURE FORECAST. WHILE I HAVE LOWERING POPS EACH
DAY...LARGELY DUE TO INCREASING UNCERTAINTY...AM KEEPING A LOW CHC
TO SLIGHT CHC IN THROUGH THE PERIOD WITH MORE INDICATION OF SOME
WINTRY PRECIP AS WE GET INTO TUES NIGHT AND WED.
OVERALL...FORECAST REALLY REFLECTS A VERY BROAD BRUSH RATHER THAN
GOING EXACTLY WITH ANY ONE SOLUTION...AND EXPECT THERE WILL BE
QUITE A FEW CHANGES TO THE EARLY WEEK FORECAST AS WE GET INTO THE
WEEKEND. NOT MUCH CHANCE FOR A MAJOR STORM DURING THIS
PERIOD...AND AFTER SUNDAY ITS POSSIBLE THAT DRY BUT COOL HIGH
PRESSURE MANAGES TO DOMINATE...BUT BEST GUESS FOR NOW IS SOMETHING
IN BETWEEN. AS ALWAYS...STAY TUNED!
&&
.AVIATION /09Z THURSDAY THROUGH MONDAY/...
AS OF 1125 PM EST WEDNESDAY...
FLYING CONDITIONS WILL GRADUALLY IMPROVE OVERNIGHT AS A COLD
FRONT SWEEPS ACROSS FROM THE WEST AND REMOVES THE LINGERING LOW
CLOUDS...FOG AND DRIZZLE THAT HAVE PERSISTED WITHIN A STRONG WEDGE
FOR THE LAST COUPLE OF DAYS. HOWEVER EASTERN SITES SUCH AS
KLYH/KDAN MAY STILL BE SLOW TO IMPROVE TO MVFR UNTIL EARLY
THURSDAY WHEN BETTER MIXING BEHIND THE FRONT DEVELOPS. THUS WILL
BE HOLDING ONTO LINGERING IFR THERE INTO THE OVERNIGHT WITH A SLOW
RISE IN BOTH CIGS AND VSBYS BY DAWN. ELSW STILL LOOKING AT MVFR
CIGS FOR THE MOST PART WITH IFR FAR WEST GIVEN UPSLOPE FLOW INTO
KBLF OVERNIGHT. A FEW SHOWERS STILL POSSIBLE OVER THE AREA DURING
THE NEXT FEW HOURS BEFORE MORE UPSLOPE NATURE RAIN/SNOW SHOWERS
GET GOING TOWARD SUNRISE.
WEST WINDS WILL REMAIN STRONG AT TIMES OVER THE WEST OVERNIGHT
WITH GUSTS TO 30-40 MPH POSSIBLE WITH LIGHTER SPEEDS WITHIN THE
LINGERING WEDGE AT KLYH/KDAN.
THURSDAY...MVFR CEILINGS AND UPSLOPE RAIN/SNOW SHOWERS SHOULD
PERSIST IN THE MOUNTAINS...MAINLY KBLF/KLWB INTO EARLY AFTERNOON
WITH VFR CONDITIONS RETURNING IN THE PIEDMONT. IN BETWEEN...SOME
LINGERING MVFR STRATO-CU POSSIBLE AROUND KBCB/KROA THURSDAY
MORNING BEFORE THINGS MIX OUT UNDER GUSTY WESTERLY WINDS BY
MIDDAY. WINDS AGAIN MAY GUST TO 25-30 KTS THURSDAY MORNING BEFORE
QUICKLY DIMINISHING DURING THURSDAY AFTERNOON AS HIGH PRESSURE
BUILDS IN.
EXTENDED DISCUSSION...
THURSDAY NIGHT AND FRIDAY HIGH PRESSURE SHOULD BUILD OVER THE
SOUTHEAST...WHICH WILL PROVIDE VFR WEATHER WITH LIGHTER WINDS.
ANOTHER COLD FRONT WITH ASSOCIATED LOW PRESSURE WILL APPROACH THE
REGION SATURDAY AND BE OVER OR JUST WEST OF THE AREA SUNDAY. GIVEN
THE SLOWER TRENDS...APPEARS WEATHER MAY STAY VFR FOR SATURDAY WITH
SUB-VFR CONDITIONS RETURNING WITH CLOUDS/PRECIP ON SUNDAY FOR NOW.
BOUNDARY MAY LINGER OVER OR JUST SOUTH OF THE REGION EARLY NEXT
WEEK WITH POSSIBLE RETURN TO VFR MONDAY AFTERNOON AT THIS POINT.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS
NEAR TERM...AMS
SHORT TERM...DS
LONG TERM...SK
AVIATION...JH/RCS
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1134 PM EST WED DEC 24 2014
.SYNOPSIS...
A COLD FRONT WILL SWING EAST ACROSS THE REGION OVERNIGHT BRINGING
GUSTY WEST WINDS AND DRIER AIR BY CHRISTMAS MORNING. HIGH
PRESSURE WILL THEN BUILD OVER THE EASTERN UNITED STATES THURSDAY INTO
THE WEEKEND WITH GENERALLY FAIR WEATHER EXPECTED INTO SATURDAY.
ANOTHER COLD FRONT ARRIVES BY SUNDAY WITH THE NEXT CHANCE OF
SHOWERS FOR LATE IN THE WEEKEND.
&&
.NEAR TERM /THROUGH THURSDAY/...
AS OF 925 PM EST WEDNESDAY...
COLD FRONT NOW PUSHING ACROSS THE FAR WESTERN COUNTIES SHOULD
REACH THE BLUE RIDGE BY MIDNIGHT AND OUT EAST DURING THE EARLY
MORNING HOURS. MOST SHOWERS HAVE ALL BUT DISSIPATED ALONG THE
BOUNDARY UPON ENCOUNTERING THE LINGERING WEDGE BUT STILL APPEARS A
FEW LIGHTER BANDS OF SHOWERS POSSIBLE OVER THE WEST DURING THE
NEXT COUPLE OF HOURS. HOWEVER NOT ENOUGH TO KEEP ANY THUNDER GOING
NW WITH A GRADUAL REDUCTION IN POPS WEST UNTIL SEEING THE BRIEF
UPSLOPE KICK IN LATER ON. OTHER CONCERN IS OUT EAST WHERE THE
FRONT WILL LIKELY SLOW UNDER THE SW FLOW ALOFT ALLOWING PERHAPS
ANOTHER SPEED MAX TO ZIP UP FROM THE SOUTH INTO THE EARLY MORNING
HOURS. LATEST HRRR CONTINUES TO SUGGEST A FEW ADDED HOURS OF RAIN
ESPCLY PIEDMONT AND SUPPORTED BY THE 00Z NAM SO ADDED IN MORE
CHANCE POPS EAST OVERNIGHT ESPCLY GIVEN FILLING BACK IN OF PRECIP
ON REGIONAL RADARS TO THE SOUTH ATTM. OTRW SEEING A TEMP DROP OF
ALMOST 10 DEGREES IN AN HOUR DURING THE FROPA WITH GUSTS TO 30-35
KTS BUT STILL BELOW ADVISORY GIVEN LEVELING OFF OF SPEEDS ONCE THE
BOUNDARY CROSSES. EXPECT FOG TO FINALLY FADE ENOUGH AFTER MIDNIGHT
TO DROP MENTION FOR THE MOST PART OVERNIGHT AS WELL. BUMPED UP LOW
TEMPS IN THE EAST WHERE ONCE THE WEDGE BREAKS EXPECT A BRIEF TEMP
SURGE FOR A COUPLE HOURS BEFORE GRADUAL COOLING REDEVELOPS BEHIND
THE FRONT. HOWEVER GIVEN MIXING EXPECT LOWS TO BE A FEW DEGREES
WARMER THAN EARLIER THOUGHT.
PREVIOUS UPDATE AS OF 520 PM EST WEDNESDAY...
SENT AN UPDATE TO BOOST DENSE FOG COVERAGE ALONG/EAST OF THE BLUE
RIDGE THIS EVENING BEFORE THE COLD FRONT FINALLY ARRIVES AND HELPS
MIX THINGS OUT BEFORE MIDNIGHT. ALSO ISSUED A SPS FOR THE
FOOTHILLS AND PIEDMONT GIVEN THE QUICK DROPOFF IN VISIBILITIES
OVER THE PAST HOUR. MAY NEED A BRIEF ADVISORY IF CONDITIONS WORSEN
BUT HOLDING OFF FOR NOW GIVEN THE GRADUAL APPROACH OF THE FRONT
FROM THE WEST. ALSO TWEAKED POPS DOWN AND ADDED MORE DRIZZLE BLUE
RIDGE EAST WHILE DELAYING CONVECTION OVER THE WEST. MOST LATEST
SHORT TERM SOLUTIONS QUICKLY WEAKEN THIS SHALLOW CONVECTION UPON
CROSSING THE WESTERN SLOPES IN THE NEXT COUPLE OF HOURS BUT
SOMETHING TO WATCH. TEMPS REMAIN STUCK IN THE 40S ACROSS THE
CENTRAL AND EAST SO ADJUSTED DOWN FOR STEADY READINGS THERE THIS
EVENING BEFORE SEEING A QUICK JUMP WHEN THE FRONT ARRIVES AFTER
00Z.
PREVIOUS DISCUSSION AS OF 340 PM EST WEDNESDAY...
AT 3 PM...THE WEDGE OF COOL SHALLOW AIR REMAINED ALONG AND EAST
OF THE BLUE RIDGE. THIS MORNING...A SHORT WAVE PASSED OVER THIS
WEDGE AND BROUGHT A FAIR AMOUNT OF RAIN (0.50 TO 1.50 INCHES) TO
THE REGION. THIS WAVE HAS PASSED WITH ONLY LIGHT RAIN/DRIZZLE LEFT
IN ITS WAKE. GRAY CLOUDY CONDITIONS WILL PERSIST INTO THIS EVENING
WHILE A LULL IN THE RAIN WILL LAST FOR A FEW HOURS BEFORE A COLD
FRONT AND ASSOCIATED SHOWERS ENTER THE WEST LATE THIS
AFTERNOON...EXITING THE PIEDMONT LATE THIS EVENING. THE WEDGE HAS
LEFT MOST OF THE AREA IN A STABLE ENVIRONMENT BUT CAN NOT RULE OUT
A RUMBLE OF THUNDER FROM ELEVATED CONVECTION AS THE COLD FRONT
PASSES THIS EVENING.
SHOWERS WITH THE FRONT MAY HAVE SOME GUSTY WINDS WITH THEM...BUT
IT WILL BE THE SHARP PRESSURE RISES BEHIND THE FRONT THAT WILL
BRING A FEW HOURS OF BREEZY AND GUSTY CONDITIONS TO THE REGION.
THE STRONGER LONGER LASTING BREEZY AND GUSTY WINDS WILL OCCUR
EARLY CHRISTMAS MORNING WITH A TIGHT PRESSURE GRADIENT...MODEST
COLD AIR ADVECTION AND A 50 KT LOW LEVEL JET. HIGH PRESSURE BUILDS
IN QUICKLY THURSDAY AFTERNOON TO SHUT DOWN THE WINDS.
AS THE WEDGE ERODES...TEMPERATURES ARE WARMING INTO THE MID TO
UPPER 50S. AREA ALONG AND EAST OF THE BLUE RIDGE...PARTICULARLY IN
THE FOOTHILLS AND PIEDMONT COUNTIES...MAY NOT SEE HIGH
TEMPERATURES TODAY UNTIL THIS EVENING (5P-7P). ONCE THE FRONT
MOVES EAST...TEMPERATURES WILL SLOWLY DROP INTO THE 30S AND 40S.
AS THE UPPER LEVEL TROUGH PASSES OVERHEAD FRIDAY MORNING...A FEW
SHOWERS ARE POSSIBLE. TEMPERATURES AND BOUNDARY LAYER ARE TO WARM
FOR SNOW EXCEPT FOR HIGHER ELEVATIONS AND WESTERN SLOPES. AFTER A
BREEZY COOL MORNING...AFTERNOON HIGHS WILL WARM INTO THE 40S WEST
TO 50S EAST.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
AS OF 250 PM EST WEDNESDAY...
TRANQUIL AND MILD CONDITIONS ARE IN STORE FOR THE INITIAL POST-
CHRISTMAS PERIOD OVER THE CENTRAL/SOUTHERN APPALACHIAN REGION. A
SURFACE AND UPPER RIDGE OF HIGH PRESSURE CENTERED OVER THE
SOUTHEASTERN U.S. WILL DOMINATE THE PATTERN IN OUR REGION FOR
SEVERAL DAYS AS UPPER TROUGHING AND STORMINESS IS CONFINED TO THE
WESTERN CONUS. VERY MILD TEMPS ON FRIDAY WITH WIDESPREAD 50S
LIKELY FOR HIGHS UNDER A PLEASANT LATE DECEMBER SUN. WINTER
WEATHER LOVERS PREPARE TO BE LESS THAN PLEASED.
THE HIGH WILL SHIFT OFF THE EAST COAST BY LATE SATURDAY AS HEIGHT
FALLS AND A COLD FRONT OVER THE MID-MISSISSIPPI VALLEY SLOWLY PUSH
EAST. SKIES WILL BE CLEAR FRIDAY NIGHT AND MOST OF SATURDAY WITH
TEMPERATURES AGAIN RUNNING 10-15F ABOVE LATE DECEMBER
NORMALS...LOWS IN LOW TO MID-30S AND HIGHS LOW 50S TO NEAR 60.
HIGH CLOUDS WILL INCREASE LATE SATURDAY AHEAD OF THE FRONT WITH
ANOTHER MILD NIGHT IN STORE AS TEMPS LIKELY TO REMAIN ABOVE
FREEZING IN NEARLY ALL AREAS. POPS SLOWLY INCREASE AS WELL TO CHC
BY EARLY SUNDAY IN THE FAR WEST WITH RAIN AS THE P-TYPE IN ALL BUT
VERY COLDEST LOCATIONS.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 300 PM EST WEDNESDAY...
LATE WEEKEND INTO MID NEXT WEEK LOOKS TO BE POTENTIALLY UNSETTLED
WITH LARGE SCALE TROUGH OVER THE WESTERN TWO THIRDS OF THE COUNTRY
KICKING SEVERAL SHORT WAVES OUT INTO SOUTHERN APPALACHIAN REGION.
MODELS OFFER SIGNIFICANT DIFFERENCES IN THE STRENGTH AND TIMING OF
THESE WAVES...AND AMOUNT OF GULF MOISTURE THEY ARE ABLE TO TAP.
ALSO RUN-TO-RUN INCONSISTENCIES ARE MAKING THIS OVERALL A RATHER
LOW CONFIDENCE FORECAST. AM CONCERNED THAT THE ECMWF IN PARTICULAR
HAS HAD A TENDENCY TO DIG THE SHORT WAVES A LITTLE TOO MUCH AND
THEN ULTIMATELY DRIVE A DEEPENING SFC WAVE TOO FAR NORTH UP THE
APPALACHIANS OR TO THE WEST OF US. THE FLATTER MORE PROGRESSIVE
GFS HAS BEEN BETTER AS OF LATE. LATEST 12Z ECMWF HAS TRENDED
TOWARD THE MORE SUBDUED GFS FOR THE FIRST SYSTEM HEADED UP OUR WAY
SUNDAY INTO MONDAY...WHILE CANADIAN NOW HAS A MUCH STRONGER SYSTEM
TRACKING JUST TO OUR SOUTH ON MONDAY AND MONDAY NIGHT. WILL LEAN
MORE TOWARD THE WEAKER/FLATTER IDEA ADVERTISED IN THE LATEST GFS
AND NOW ECMWF...AT LEAST THROUGH TUES. ECWMF IS A LITTLE STRONGER
WITH ANOTHER WAVE ON WEDNESDAY...WHILE GFS IS
FASTER...COLDER...AND GENERALLY KEEPS IT SOUTH OF US.
WHILE CONFIDENCE IN THE TIMING AND STRENGTH OF THESE SYSTEMS IS
QUITE LOW RIGHT NOW...THERE IS MORE CLARITY THAT THIS WILL AT THE
VERY LEAST BE A CLOUDY PERIOD...AND THAT LOW LEVEL TEMPS AND
THICKNESSES WILL GENERALLY BE WARM ENOUGH NOT TO HAVE ANY REAL
PRECIP TYPE CONCERNS...WITH THE POSSIBLE EXCEPT OF HIGHEST RIDGES
ACROSS THE FAR NORTH SUNDAY AND MONDAY...WITH ANY SYSTEM ON
WEDNESDAY THERE COULD BE ENOUGH DAMMING SETTING UP THAT
OVERRUNNING COULD BE SOME SORT OF WINTRY MIX...BUT NOT EVEN SURE
WE WILL HAVE PRECIP ON WED. ECMWF WOULD SUGGEST FREEZING RAIN.
A LITTLE MORE CONFIDENCE AT THE BEGINNING OF THIS PERIOD...SO
HAVE SOME LIKELY AND HIGH CHC POPS IN FOR SUNDAY...BUT ALL
RAIN...AND MOST LIKELY LIGHT. AS WE GET INTO THE WEEK...THE LARGE
SFC HIGH NOSES IN MORE AND MORE AND EACH DAY LOOKS A LITTLE COOLER
THAN THE PREVIOUS ONE WHICH IS REFLECTED IN THE TEMPERATURE
FORECAST. WHILE I HAVE LOWERING POPS EACH DAY...LARGELY DUE TO
INCREASING UNCERTAINTY...AM KEEPING A LOW CHC TO SLIGHT CHC IN
THROUGH THE PERIOD WITH MORE INDICATION OF SOME WINTRY PRECIP AS
WE GET INTO TUES NIGHT AND WED. OVERALL...FORECAST REALLY REFLECTS
A VERY BROAD BRUSH RATHER THAN GOING EXACTLY WITH ANY ONE
SOLUTION...AND EXPECT THERE WILL BE QUITE A FEW CHANGES TO THE
EARLY WEEK FORECAST AS WE GET INTO THE WEEKEND. NOT MUCH CHANCE
FOR A MAJOR STORM DURING THIS PERIOD...AND AFTER SUNDAY ITS
POSSIBLE THAT DRY BUT COOL HIGH PRESSURE MANAGES TO DOMINATE...BUT
BEST GUESS FOR NOW IS SOMETHING IN BETWEEN. AS ALWAYS...STAY
TUNED!
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
AS OF 1125 PM EST WEDNESDAY...
FLYING CONDITIONS WILL GRADUALLY IMPROVE OVERNIGHT AS A COLD
FRONT SWEEPS ACROSS FROM THE WEST AND REMOVES THE LINGERING LOW
CLOUDS...FOG AND DRIZZLE THAT HAVE PERSISTED WITHIN A STRONG WEDGE
FOR THE LAST COUPLE OF DAYS. HOWEVER EASTERN SITES SUCH AS
KLYH/KDAN MAY STILL BE SLOW TO IMPROVE TO MVFR UNTIL EARLY
THURSDAY WHEN BETTER MIXING BEHIND THE FRONT DEVELOPS. THUS WILL
BE HOLDING ONTO LINGERING IFR THERE INTO THE OVERNIGHT WITH A SLOW
RISE IN BOTH CIGS AND VSBYS BY DAWN. ELSW STILL LOOKING AT MVFR
CIGS FOR THE MOST PART WITH IFR FAR WEST GIVEN UPSLOPE FLOW INTO
KBLF OVERNIGHT. A FEW SHOWERS STILL POSSIBLE OVER THE AREA DURING
THE NEXT FEW HOURS BEFORE MORE UPSLOPE NATURE RAIN/SNOW SHOWERS
GET GOING TOWARD SUNRISE.
WEST WINDS WILL REMAIN STRONG AT TIMES OVER THE WEST OVERNIGHT
WITH GUSTS TO 30-40 MPH POSSIBLE WITH LIGHTER SPEEDS WITHIN THE
LINGERING WEDGE AT KLYH/KDAN.
THURSDAY...MVFR CEILINGS AND UPSLOPE RAIN/SNOW SHOWERS SHOULD
PERSIST IN THE MOUNTAINS...MAINLY KBLF/KLWB INTO EARLY AFTERNOON
WITH VFR CONDITIONS RETURNING IN THE PIEDMONT. IN BETWEEN...SOME
LINGERING MVFR STRATO-CU POSSIBLE AROUND KBCB/KROA THURSDAY
MORNING BEFORE THINGS MIX OUT UNDER GUSTY WESTERLY WINDS BY
MIDDAY. WINDS AGAIN MAY GUST TO 25-30 KTS THURSDAY MORNING BEFORE
QUICKLY DIMINISHING DURING THURSDAY AFTERNOON AS HIGH PRESSURE
BUILDS IN.
EXTENDED DISCUSSION...
THURSDAY NIGHT AND FRIDAY HIGH PRESSURE SHOULD BUILD OVER THE
SOUTHEAST...WHICH WILL PROVIDE VFR WEATHER WITH LIGHTER WINDS.
ANOTHER COLD FRONT WITH ASSOCIATED LOW PRESSURE WILL APPROACH THE
REGION SATURDAY AND BE OVER OR JUST WEST OF THE AREA SUNDAY. GIVEN
THE SLOWER TRENDS...APPEARS WEATHER MAY STAY VFR FOR SATURDAY WITH
SUB-VFR CONDITIONS RETURNING WITH CLOUDS/PRECIP ON SUNDAY FOR NOW.
BOUNDARY MAY LINGER OVER OR JUST SOUTH OF THE REGION EARLY NEXT
WEEK WITH POSSIBLE RETURN TO VFR MONDAY AFTERNOON AT THIS POINT.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...JH/RCS
NEAR TERM...JH/RCS
SHORT TERM...PC
LONG TERM...SK
AVIATION...JH/RCS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
254 PM CST THU DEC 25 2014
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 254 PM CST THU DEC 25 2014
MAIN FORECAST CONCERNS ARE ON LIGHT FREEZING DRIZZLE POTENTIAL
TONIGHT. FOCUS THEN TURNS TO SNOW ACCUMULATIONS FRIDAY NIGHT
THROUGH SATURDAY MORNING.
LIGHT FREEZING DRIZZLE OR SNOW IS POSSIBLE TONIGHT OVER PORTIONS OF
SOUTHEAST MINNESOTA INTO NORTH CENTRAL WISCONSIN. A MID LEVEL
TROUGH WILL PUSH EAST OUT OF THE DAKOTAS TONIGHT INTO FRIDAY
PRODUCING A BAND OF LIGHT SNOW AND POSSIBLY LIGHT FREEZING
DRIZZLE...MAINLY NORTHWEST OF THE FORECAST AREA. CONFIDENCE IS LOW
ON THE FREEZING DRIZZLE OCCURRING TONIGHT SO DECIDED TO KEEP IT
AS PROBABILITY INSTEAD OF COVERAGE. IF THE DRIZZLE DEVELOPS...SOME
VERY LIGHT ICING IS POSSIBLE ON UNTREATED ROADS AND ELEVATED
SURFACES. ALSO...MESOSCALE MODELS ARE SUGGESTING THE POTENTIAL FOR
SOME FOG TONIGHT RIGHT ALONG THE SURFACE TROUGH LATE TONIGHT INTO
FRIDAY MORNING. WILL HAVE TO KEEP AN EYE ON THIS DURING THE
EVENING AND OVERNIGHT HOURS. OTHERWISE PLAN ON LOWS FALLING INTO
THE UPPER 20S TO LOWER 30S TONIGHT.
ANOTHER TROUGH MOVES EAST OUT OF THE NORTHERN PLAINS FRIDAY AS A
SEPARATE TROUGH LIFTS NORTHEAST OUT OF THE SOUTHWEST CONUS. SNOW AND
RAIN LOOKS TO DEVELOP LATE FRIDAY AFTERNOON...INCREASING IN
COVERAGE GOING INTO FRIDAY NIGHT. OTHERWISE...PLAN ON MOSTLY
CLOUDY SKIES WITH AREAS OF DRIZZLE AND POSSIBLY SOME FOG ON FRIDAY
WITH HIGH TEMPERATURES RANGING FROM THE LOWER 30S OVER SOUTHEAST
MINNESOTA INTO NORTH CENTRAL WISCONSIN TO AROUND 40 ACROSS FAR
SOUTHWEST WISCONSIN.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 254 PM CST THU DEC 25 2014
BY FRIDAY EVENING...A BAND OF SNOW SHOULD BE IN PLACE FROM PORTIONS
OF NORTHEAST IOWA...SOUTHEAST MINNESOTA...INTO NORTH CENTRAL
WISCONSIN. A MIX OF RAIN OR SNOW IS EXPECTED ACROSS FAR NORTHEAST
IOWA INTO SOUTHWEST WISCONSIN. THERE IS UNCERTAINTY ON WHETHER OR
NOT THE SOUTHERN STREAM AND NORTHERN STREAM TROUGHS WILL INTERACT
ACROSS THE UPPER MISSISSIPPI RIVER VALLEY. THE NAM AND GFS OFFER
MORE PROGRESSIVE SOLUTIONS WHICH WOULD YIELD LIGHTER SNOWFALL
AMOUNTS. THE GEM AND ECMWF SOLUTIONS ARE MUCH STRONGER...AND
DEEPEN THE TROUGH OVER THE FORECAST AREA. IF THESE STRONGER
SOLUTIONS VERIFY...WE WOULD SEE SNOW ACCUMULATIONS IN THE 2 TO 4
INCH RANGE WITH HIGHER AMOUNTS POSSIBLE. EITHER WAY...TRAVEL WILL
BE IMPACTED BY THIS SYSTEM WITH SLIPPERY ROADS EXPECTED FRIDAY
NIGHT INTO SATURDAY MORNING. CONFIDENCE IS HIGH ON SEEING
ACCUMULATIONS IN THE 1 TO 2 INCH RANGE. LOW CONFIDENCE ON SEEING
AMOUNTS IN THE 2 TO 4 INCH PLUS RANGE AT THIS TIME.
THE STORM SYSTEM WILL EXIT THE REGION LATE SATURDAY AFTERNOON INTO
SATURDAY NIGHT WITH SEASONABLE TEMPERATURES EXPECTED THROUGH SUNDAY.
A MUCH COLDER AIRMASS THEN SWEEPS INTO THE REGION MONDAY AFTERNOON
INTO MONDAY NIGHT WITH TEMPERATURES PLUMMETING INTO THE SINGLE
DIGITS BELOW ZERO ACROSS MUCH OF THE REGION. SOME LIGHT SNOW IS
POSSIBLE MONDAY AFTERNOON MAINLY SOUTH OF INTERSTATE 90 AS A WEAK
SHORTWAVE MOVES THROUGH. OTHERWISE...THE MAIN FOCUS IS ON THE COLD
TEMPERATURES MOVING IN. HIGHS WILL ONLY BE IN THE SINGLE DIGITS
TO LOWER TEENS TUESDAY..WITH LOWS FALLING INTO THE SINGLE DIGITS
BELOW ZERO TUESDAY NIGHT. WIND CHILLS MAY ALSO BE A CONCERN MONDAY
NIGHT AND TUESDAY NIGHT OVER THE OPEN AREAS OF NORTHEAST IOWA...
SOUTHEAST MINNESOTA AND NORTH CENTRAL WISCONSIN WHERE WIND CHILL
VALUES COULD FALL TO AROUND -20.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1132 AM CST THU DEC 25 2014
THE SOUTH TO SOUTHWESTERLY FLOW ABOVE THE GROUND HAS BEEN STRONG
ENOUGH TO HELP BRING IN SOME DRIER AIR FROM IOWA AND SCATTER OUT
THE CLOUDS AT RST. RAP MODEL RUNS HAVE BEEN A BIT TOO
PESSIMISTIC...SO HAVE REVERTED AND MADE THE TAFS MORE OPTIMISTIC.
HAVE NOW BROUGHT SCATTERING TO VFR CONDITIONS AT LSE AT 21Z. A
CONDITIONS SHOULD REMAIN VFR THROUGH A GOOD DEAL OF TONIGHT. LATE
IN THE NIGHT...A TROUGH OVER SOUTHWEST MN LOOKS ON TRACK TO CROSS
RST...AND TOWARDS SUNRISE AT LSE. LOW CEILING STRATUS RETURNS IN
THE WAKE OF THE TROUGH...WITH RST LIKELY DROPPING TO IFR AND
LIFR. MEANWHILE...THE VALLEY SHOULD HELP PREVENT LSE FROM DROPPING
BELOW MVFR. ADDITIONALLY...SOME LOWER VISIBILITIES APPEAR LIKELY
TO ACCOMPANY THE LOW STRATUS...PARTICULARLY OVER THE HIGHER
TERRAIN SITE OF RST. SOME GUIDANCE WANTS TO BRING THEM DOWN TO
LIFR. CONFIDENCE ONLY HIGH ENOUGH TO BRING IT DOWN TO IFR. THERE
COULD ALSO BE SOME PATCHY FREEZING DRIZZLE WITH THESE LOW
VISIBILITIES. COVERAGE AT THIS TIME NOT WIDESPREAD ENOUGH TO
INCLUDE IN THE TAF.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...WETENKAMP
LONG TERM...WETENKAMP
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1132 AM CST THU DEC 25 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 342 AM CST THU DEC 25 2014
THE MAIN FOCUS FOR TODAY IS WITH THE CLOUD COVER/TEMPERATURES
FOLLOWED BY THE CHANCES FOR DRIZZLE/FREEZING DRIZZLE TONIGHT.
CURRENTLY...A SURFACE RIDGE OF HIGH PRESSURE IS ALIGNED ALONG THE
MISSISSIPPI RIVER AND DRIFTING EASTWARD AS A BROAD AREA OF LOW
PRESSURE DEVELOPS IN THE PLAINS. FURTHER ALOFT...THE MID LEVEL
FLOW IS FLATTENING OUT ACROSS THE NORTHERN PLAINS/UPPER
MISSISSIPPI RIVER VALLEY AS A TROUGH DIGS ACROSS THE ROCKIES. A
LOW LEVEL STRATUS DECK IS PRODUCING SOME SCATTERED FLURRIES DUE TO
THE TOP OF THE SATURATED LAYER/CLOUD DECK BEING AROUND -10C
ACCORDING TO IR SATELLITE. THIS IS COLDER THAN WHAT LOCAL SHORT
TERM SOUNDINGS SUGGEST IS OCCURRING. IR SATELLITE/OBS ACTUALLY
SHOW THE WESTERN EDGE OF IT RAPIDLY CLEARING IN ACROSS CENTRAL
IOWA/SOUTHWEST MINNESOTA AND IS TIMED TO BE MOVING THROUGH THE
REGION THIS MORNING INTO EARLY AFTERNOON WITH EROSION OCCURRING
FROM SOUTHWEST TO NORTHEAST. HOWEVER...HIGH LEVEL CLOUD COVER IS
QUICK ON ITS HEELS AND WILL LIMIT THE POTENTIAL OF SEEING ANY
SUNLIGHT UNLESS IT ENDS UP THINNING OUT AS IT APPROACHES. BASED
ON THE LOW CLOUDS CLEARING OUT...BUMPED UP FORECAST HIGH
TEMPERATURES A FEW DEGREES AS SURFACE WINDS COME AROUND TO THE
SOUTHWEST AND BRING SOME WARMER AIR INTO THE REGION.
GOING INTO TONIGHT THE QUESTION IS WITH WHETHER ANY
DRIZZLE/FREEZING DRIZZLE WILL OCCUR AS LOW LEVEL MOISTURE
TRANSPORT RAMPS UP INTO THE REGION. THE 25.00Z MODELS ARE ALL IN
AGREEMENT THAT A 30-40KT LOW LEVEL JET WILL DEVELOP ACROSS THE
SOUTHERN PLAINS THIS EVENING WITH IT NOSING NORTHEASTWARD AS THE
NIGHT PROGRESSES. FORECAST SOUNDINGS FROM THE NAM/GFS BOTH SHOW A
DEEPENING SATURATED LOW LEVEL LAYER WHICH IS NOT COLD ENOUGH TO
FORM ICE. THERE APPEARS TO BE SOME WEAK LIFT THANKS TO THE LLJ
NOSE/SURFACE BOUNDARY PROVIDING SOME CONVERGENCE. THE 25.00/06Z
NAM SURFACE REFLECTIVITY PANES SHOW THIS DRIZZLE DEVELOPING FROM
THE WEST OVERNIGHT...PARTICULARLY AFTER MIDNIGHT AND ALONG WHERE
THE CONVERGENCE IS IN THE SURFACE/LOW LEVELS. WITH THE SOUTHERLY
WINDS KEEPING THE WARMER AIR IN PLACE...THERE IS SOME QUESTION
ABOUT HOW COLD TEMPERATURES WILL BE AND WHETHER THE DRIZZLE WILL
BE FREEZING OR NOT. WILL HAVE TO MONITOR TRENDS...BUT WITH
TEMPERATURES AT OR JUST ABOVE FREEZING...EXPECT THAT THE IMPACT
WILL NOT BE THAT GREAT.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 342 AM CST THU DEC 25 2014
GOING INTO THIS WEEKEND ON INTO THE MIDDLE OF NEXT WEEK...THE
FOCUS IS ON THE POTENTIAL FOR AN ACCUMULATING SNOW FRIDAY NIGHT
INTO SATURDAY FOLLOWED BY THE DRASTICALLY COLDER AIR MASS THAT
WILL SETTLE IN BY MIDWEEK.
EYES WILL BE ON THE MID LEVEL TROUGH DIGGING ACROSS THE
SOUTHWESTERN US AND HOW IT WILL EJECT INTO THE UPPER MIDWEST.
PREVIOUS MODEL RUNS HAD THIS WAVE COMING THROUGH AS MAINLY AN OPEN
TROUGH/SURFACE LOW BUT THE 25.00Z TRENDS WITH THE NAM/GFS/ECMWF
ARE TO GO DEEPER. THE ECMWF IS THE DEEPEST/SLOWEST WITH THIS
FEATURE AND BRINGS THE HEAVIEST SNOW TOTALS...POSSIBLY ADVISORY
WORTHY...ALONG WITH IT. ALL THREE MODELS ARE SHOWING A BAND OF
HEAVIER SNOW OCCURRING IN THE DEFORMATION AREA OF THE TROUGH WHICH
RUNS FROM SOUTHEAST MINNESOTA INTO NORTH CENTRAL WISCONSIN. MOST
OF THE AREA SHOULD JUST SEE SNOW FROM THIS SYSTEM...BUT SOME
PORTIONS OF EASTERN IOWA AND SOUTHWEST WISCONSIN COULD BE WARM
ENOUGH TO CHANGE IT OVER TO RAIN. THE ECMWF TRENDS WILL HAVE TO BE
MONITORED BECAUSE IT WOULD SET US UP FOR SOME HIGHER SNOWFALL
TOTALS THAN CURRENTLY BEING FORECAST. WITH IT BEING A NEW
DIRECTION BEING TAKEN WITH THIS ONE MODEL...DECIDED IT WOULD BE
BEST TO JUST BLEND THAT SOLUTION WITH THE NAM/GFS IDEA TO COME UP
WITH SNOW ACCUMULATIONS OF 1 TO 3 INCHES. THE MAIN PERIOD TO WATCH
WILL BE SATURDAY MORNING AS THE ECMWF HAS AROUND 0.25 INCHES OF
QPF IN THAT PERIOD WHEN THE NAM/GFS ONLY HAS 0.01 INCHES OR SO.
BEYOND THIS SYSTEM IT LOOKS LIKE WE WILL HAVE AN EXTENDED PERIOD
OF HAVING A COLDER AIR MASS WHERE HIGHS ONLY GET INTO THE
TEENS...PARTICULARLY GOING INTO TUESDAY AND WEDNESDAY. PERHAPS THE
SILVER LINING HERE IS THAT WITH THIS COLD AIR AND A BROAD RIDGE OF
HIGH PRESSURE DROPPING DOWN ACROSS MUCH OF THE CENTRAL US...SKIES
SHOULD BE CLEAR WHICH WOULD BE WELCOME AFTER THIS EXTENDED PERIOD
OF OVERCAST CONDITIONS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1132 AM CST THU DEC 25 2014
THE SOUTH TO SOUTHWESTERLY FLOW ABOVE THE GROUND HAS BEEN STRONG
ENOUGH TO HELP BRING IN SOME DRIER AIR FROM IOWA AND SCATTER OUT
THE CLOUDS AT RST. RAP MODEL RUNS HAVE BEEN A BIT TOO
PESSIMISTIC...SO HAVE REVERTED AND MADE THE TAFS MORE OPTIMISTIC.
HAVE NOW BROUGHT SCATTERING TO VFR CONDITIONS AT LSE AT 21Z. A
CONDITIONS SHOULD REMAIN VFR THROUGH A GOOD DEAL OF TONIGHT. LATE
IN THE NIGHT...A TROUGH OVER SOUTHWEST MN LOOKS ON TRACK TO CROSS
RST...AND TOWARDS SUNRISE AT LSE. LOW CEILING STRATUS RETURNS IN
THE WAKE OF THE TROUGH...WITH RST LIKELY DROPPING TO IFR AND
LIFR. MEANWHILE...THE VALLEY SHOULD HELP PREVENT LSE FROM DROPPING
BELOW MVFR. ADDITIONALLY...SOME LOWER VISIBILITIES APPEAR LIKELY
TO ACCOMPANY THE LOW STRATUS...PARTICULARLY OVER THE HIGHER
TERRAIN SITE OF RST. SOME GUIDANCE WANTS TO BRING THEM DOWN TO
LIFR. CONFIDENCE ONLY HIGH ENOUGH TO BRING IT DOWN TO IFR. THERE
COULD ALSO BE SOME PATCHY FREEZING DRIZZLE WITH THESE LOW
VISIBILITIES. COVERAGE AT THIS TIME NOT WIDESPREAD ENOUGH TO
INCLUDE IN THE TAF.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
946 AM CST THU DEC 25 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 342 AM CST THU DEC 25 2014
THE MAIN FOCUS FOR TODAY IS WITH THE CLOUD COVER/TEMPERATURES
FOLLOWED BY THE CHANCES FOR DRIZZLE/FREEZING DRIZZLE TONIGHT.
CURRENTLY...A SURFACE RIDGE OF HIGH PRESSURE IS ALIGNED ALONG THE
MISSISSIPPI RIVER AND DRIFTING EASTWARD AS A BROAD AREA OF LOW
PRESSURE DEVELOPS IN THE PLAINS. FURTHER ALOFT...THE MID LEVEL
FLOW IS FLATTENING OUT ACROSS THE NORTHERN PLAINS/UPPER
MISSISSIPPI RIVER VALLEY AS A TROUGH DIGS ACROSS THE ROCKIES. A
LOW LEVEL STRATUS DECK IS PRODUCING SOME SCATTERED FLURRIES DUE TO
THE TOP OF THE SATURATED LAYER/CLOUD DECK BEING AROUND -10C
ACCORDING TO IR SATELLITE. THIS IS COLDER THAN WHAT LOCAL SHORT
TERM SOUNDINGS SUGGEST IS OCCURRING. IR SATELLITE/OBS ACTUALLY
SHOW THE WESTERN EDGE OF IT RAPIDLY CLEARING IN ACROSS CENTRAL
IOWA/SOUTHWEST MINNESOTA AND IS TIMED TO BE MOVING THROUGH THE
REGION THIS MORNING INTO EARLY AFTERNOON WITH EROSION OCCURRING
FROM SOUTHWEST TO NORTHEAST. HOWEVER...HIGH LEVEL CLOUD COVER IS
QUICK ON ITS HEELS AND WILL LIMIT THE POTENTIAL OF SEEING ANY
SUNLIGHT UNLESS IT ENDS UP THINNING OUT AS IT APPROACHES. BASED
ON THE LOW CLOUDS CLEARING OUT...BUMPED UP FORECAST HIGH
TEMPERATURES A FEW DEGREES AS SURFACE WINDS COME AROUND TO THE
SOUTHWEST AND BRING SOME WARMER AIR INTO THE REGION.
GOING INTO TONIGHT THE QUESTION IS WITH WHETHER ANY
DRIZZLE/FREEZING DRIZZLE WILL OCCUR AS LOW LEVEL MOISTURE
TRANSPORT RAMPS UP INTO THE REGION. THE 25.00Z MODELS ARE ALL IN
AGREEMENT THAT A 30-40KT LOW LEVEL JET WILL DEVELOP ACROSS THE
SOUTHERN PLAINS THIS EVENING WITH IT NOSING NORTHEASTWARD AS THE
NIGHT PROGRESSES. FORECAST SOUNDINGS FROM THE NAM/GFS BOTH SHOW A
DEEPENING SATURATED LOW LEVEL LAYER WHICH IS NOT COLD ENOUGH TO
FORM ICE. THERE APPEARS TO BE SOME WEAK LIFT THANKS TO THE LLJ
NOSE/SURFACE BOUNDARY PROVIDING SOME CONVERGENCE. THE 25.00/06Z
NAM SURFACE REFLECTIVITY PANES SHOW THIS DRIZZLE DEVELOPING FROM
THE WEST OVERNIGHT...PARTICULARLY AFTER MIDNIGHT AND ALONG WHERE
THE CONVERGENCE IS IN THE SURFACE/LOW LEVELS. WITH THE SOUTHERLY
WINDS KEEPING THE WARMER AIR IN PLACE...THERE IS SOME QUESTION
ABOUT HOW COLD TEMPERATURES WILL BE AND WHETHER THE DRIZZLE WILL
BE FREEZING OR NOT. WILL HAVE TO MONITOR TRENDS...BUT WITH
TEMPERATURES AT OR JUST ABOVE FREEZING...EXPECT THAT THE IMPACT
WILL NOT BE THAT GREAT.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 342 AM CST THU DEC 25 2014
GOING INTO THIS WEEKEND ON INTO THE MIDDLE OF NEXT WEEK...THE
FOCUS IS ON THE POTENTIAL FOR AN ACCUMULATING SNOW FRIDAY NIGHT
INTO SATURDAY FOLLOWED BY THE DRASTICALLY COLDER AIR MASS THAT
WILL SETTLE IN BY MIDWEEK.
EYES WILL BE ON THE MID LEVEL TROUGH DIGGING ACROSS THE
SOUTHWESTERN US AND HOW IT WILL EJECT INTO THE UPPER MIDWEST.
PREVIOUS MODEL RUNS HAD THIS WAVE COMING THROUGH AS MAINLY AN OPEN
TROUGH/SURFACE LOW BUT THE 25.00Z TRENDS WITH THE NAM/GFS/ECMWF
ARE TO GO DEEPER. THE ECMWF IS THE DEEPEST/SLOWEST WITH THIS
FEATURE AND BRINGS THE HEAVIEST SNOW TOTALS...POSSIBLY ADVISORY
WORTHY...ALONG WITH IT. ALL THREE MODELS ARE SHOWING A BAND OF
HEAVIER SNOW OCCURRING IN THE DEFORMATION AREA OF THE TROUGH WHICH
RUNS FROM SOUTHEAST MINNESOTA INTO NORTH CENTRAL WISCONSIN. MOST
OF THE AREA SHOULD JUST SEE SNOW FROM THIS SYSTEM...BUT SOME
PORTIONS OF EASTERN IOWA AND SOUTHWEST WISCONSIN COULD BE WARM
ENOUGH TO CHANGE IT OVER TO RAIN. THE ECMWF TRENDS WILL HAVE TO BE
MONITORED BECAUSE IT WOULD SET US UP FOR SOME HIGHER SNOWFALL
TOTALS THAN CURRENTLY BEING FORECAST. WITH IT BEING A NEW
DIRECTION BEING TAKEN WITH THIS ONE MODEL...DECIDED IT WOULD BE
BEST TO JUST BLEND THAT SOLUTION WITH THE NAM/GFS IDEA TO COME UP
WITH SNOW ACCUMULATIONS OF 1 TO 3 INCHES. THE MAIN PERIOD TO WATCH
WILL BE SATURDAY MORNING AS THE ECMWF HAS AROUND 0.25 INCHES OF
QPF IN THAT PERIOD WHEN THE NAM/GFS ONLY HAS 0.01 INCHES OR SO.
BEYOND THIS SYSTEM IT LOOKS LIKE WE WILL HAVE AN EXTENDED PERIOD
OF HAVING A COLDER AIR MASS WHERE HIGHS ONLY GET INTO THE
TEENS...PARTICULARLY GOING INTO TUESDAY AND WEDNESDAY. PERHAPS THE
SILVER LINING HERE IS THAT WITH THIS COLD AIR AND A BROAD RIDGE OF
HIGH PRESSURE DROPPING DOWN ACROSS MUCH OF THE CENTRAL US...SKIES
SHOULD BE CLEAR WHICH WOULD BE WELCOME AFTER THIS EXTENDED PERIOD
OF OVERCAST CONDITIONS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 946 AM CST THU DEC 25 2014
946 AM UPDATE...LAST FEW MODEL RUNS OF THE RAP AS WELL AS TRENDS
IN OBSERVATIONS IN SOUTHEAST MINNESOTA HAVE SHOWN THAT THE STRATUS
REMAINS STUCK. AS SUCH...HAVE WENT MORE PESSIMISTIC WITH THE
FORECASTS AND HAVE HELD LOW CEILINGS IN PLACE FOR THE NEXT 24
HOURS. DID ALLOW RST TO CLIMB TO MVFR THIS AFTERNOON AS DAYTIME
HEATING HELPS. ADDITIONALLY...THERE APPEARS THERE COULD BE A BRIEF
SCATTERING OF THE CLOUDS AT LSE BETWEEN 21-01Z...WHICH HAVE BEEN
HONORED WITH A TEMPO GROUP.
541 AM DISCUSSION...
CURRENTLY WATCHING BACK EDGE OF IFR/MVFR STRATUS ACROSS SOUTH
CENTRAL MN INTO EASTERN IA ERODING NORTHEASTWARD TOWARD THE
KRST/KLSE TAF SITES. EXPECTING KRST TO BREAK OUT OF STRATUS BY
15Z AND KLSE BY 17Z. AS THIS CLEARS OUT...LOOK FOR ALTOCUMULUS TO
SPREAD IN FROM THE WEST AHEAD OF A WEAK AREA OF LOW PRESSURE OVER
THE PLAINS. AS THIS LOW CLOSES IN ON THE REGION TONIGHT...PLAN ON
A RETURN OF MVFR STRATUS BETWEEN 03-05Z. KRST LOOKS TO DIP INTO
IFR AFTER 09Z. WITH THE RETURN OF THIS STRATUS AND WEAK
LIFT...EXPECTING PATCHY LIGHT FREEZING DRIZZLE TO DEVELOP AFTER
MIDNIGHT. FEEL THIS DRIZZLE WILL BE HIT AND MISS...SO OPTED NOT TO
INCLUDE IN THE BODY OF THE TAFS AT THIS POINT.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...DAS/AJ
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1156 PM MST FRI DEC 26 2014
.UPDATE...
ISSUED AT 1153 PM MST FRI DEC 26 2014
WILL ALLOW THE REMAINING WINTER HIGHLIGHTS TO EXPIRE AT MIDNIGHT.
LATEST RAP AND ARW MODELS SHOW LIGHT SNOW CONTINUING TO DECREASE IN
AREAL COVERAGE OVERNIGHT. KJGX RADAR RETURNS WERE ALSO SHRINKING.
EXPECT ANY ADDITIONAL SNOW ACCUMULATIONS TO BE GENERALLY LESS
THAN AN INCH.
THE NEXT STORM EXPECTED TO AFFECT OUR AREA IN THE SUNDAY AND MONDAY
WAS CURRENTLY MOVING DOWN THE ALASKAN PANHANDLE PER SATELLITE
IMAGES.
UPDATE ISSUED AT 937 PM MST FRI DEC 26 2014
THIS LATEST STORM CONTINUES TO WIND DOWN THIS EVENING WITH THE
UPPER TROUGH AXIS FROM AZ ACROSS CO TO THE NORTHERN PLAINS.
SATELLITE WATER VAPOR IMAGES INDICATED A SMALL JET MAX NEAR THE
ID/NV/UT TRIPLE POINT...WHICH MAY KEEP THE BASE OF THE TROUGH
HANGING BACK OVER THE DESERT SOUTHWEST UNTIL MORNING. LIGHT SNOW WAS
STILL OBSERVED AT MANY WRN CO SITES...BUT GJX RADAR ECHOES WERE
SLOWING SHRINKING. IF THIS TREND CONTINUES WILL PROBABLY LET THE
REMAINING WINTER HIGHLIGHTS EXPIRE AT MIDNIGHT THOUGH IT IS LIKELY
THAT AREAS OF LIGHT SNOW WILL PERSIST THROUGH THE NIGHT IN THE
COLD NW FLOW. COLD TEMPS IN STORE TONIGHT.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 318 PM MST FRI DEC 26 2014
UPPER LEVEL LOW CONTINUES TO MOVE EAST ACROSS THE FORECAST AREA
THIS AFTERNOON. LIGHT SNOW WILL CONTINUE TO FALL IN MANY LOCATIONS
BEFORE DIMINISHING THIS EVENING. HAVE ALLOW CURRENT HIGHLIGHTS FOR
LOWER VALLEYS TO EXPIRE AT 3PM AND HAVE CANCELLED HIGHLIGHTS FOR
ALL OF UTAH AND LOWER ELEVATIONS OF COLORADO WITH THE EXCEPTION OF
SOUTHWEST COLORADO 22/23 WHERE HIGHLIGHTS WILL CONTINUE. HAVE
ALSO ALLOWED HIGHLIGHTS TO CONTINUE FOR THE MOUNTAINS OF WESTERN
COLORADO.
AS THE UPPER LOW MOVES EAST OVERNIGHT...EXPECT PRECIPITATION TO
DIMINISH FROM WEST TO EAST THIS EVENING. THE BEST ACCUMULATION WILL
BE OVER COLORADO MOUNTAIN LOCATIONS WHERE A FEW INCHES OF
ADDITIONAL ACCUMULATION IS POSSIBLE. EXPECT VERY COLD TEMPERATURES
BY SATURDAY MORNING WITH 700 MB TEMPERATURES AROUND -16C.
NORTHERLY DRY FLOW WILL DOMINATE THE WEATHER PATTERN SATURDAY WITH
COLD TEMPERATURES AND PARTLY CLOUDY SKIES EXPECTED. THE NEXT
SYSTEM WILL DROP SOUTH INTO THE NORTHERN GREAT BASIN BY SATURDAY
NIGHT AND BRING INCREASING CLOUDS FROM THE NORTH WITH A SLIGHT
CHANCE OF SNOW OVER NORTHERN SECTIONS BY EARLY SUNDAY MORNING.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 318 PM MST FRI DEC 26 2014
A COMPLICATED STORM SYSTEM WILL DOMINATE THE WEATHER PATTERN FOR
SUNDAY INTO THE WORKWEEK. A LOW PRESSURE SYSTEM WILL DROP SOUTH
INTO THE GREAT BASIN REGION ON SUNDAY AND MONDAY BEFORE CLOSING
OFF OVER NEVADA BY TUESDAY. THE RESULTANT DEFORMATION ZONE WILL
SPREAD PERIODS OF LIGHT TO MODERATE SNOW OVER THE NORTHERN
SECTIONS OF COLORADO ON SUNDAY MORNING AND SPREAD ACROSS THE
CENTRAL AND SOUTHERN MOUNTAINS LATER SUNDAY AND CONTINUE INTO
TUESDAY. MODELS ARE STILL SHOWING SOME INCONSISTENCIES REGARDING
TIMING AND LOCATION OF THE TRACK OF THIS SYSTEM. HOWEVER...BASED
ON CURRENT GUIDANCE EXPECT A PERIOD OF UNSETTLED WEATHER THROUGH
TUESDAY WITH THE POTENTIAL FOR MODERATE ACCUMULATIONS ESPECIALLY
OVER MOUNTAIN LOCATIONS WHICH MAY REQUIRE WINTER WEATHER
HIGHLIGHTS. BY MIDWEEK THE CLOSED LOW IS FORECASTED TO EJECT
SLOWLY EAST...SOUTH OF OUR FORECAST AREA WITH SOME POTENTIAL
IMPACT FOR SOUTHERN SECTIONS OF THE FORECAST AREA BUT FORECAST
CONFIDENCE IS LOW ON THIS MODEL SOLUTION AT THIS TIME.
TEMPERATURES ARE EXPECTED TO REMAIN BELOW NORMAL THROUGH THE
PERIOD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 937 PM MST FRI DEC 26 2014
THE UPPER LEVEL TROUGH WILL SLOWLY SLIP EASTWARD TONIGHT WITH
FLOW ALOFT BECOMING NORTHWEST. MVFR CIGS/VSBY WITH AREAS OF LIGHT
SNOW WILL PERSIST OVER NW CO AND ALL CO MTNS OVERNIGHT WITH MTN
TOPS OBSCURED. LCL IFR CIGS. CONDITIONS IMPROVE OVER ERN UT AND
THE FOUR CORNERS OVERNIGHT AND AFTER 12Z-15Z ACROSS WRN CO AS HIGH
PRESSURE TEMPORARILY BUILDS IN. HIGH CLOUDS SPREAD ACROSS NERN UT
AND NWRN CO SATURDAY AFTERNOON AS A PRECURSOR TO THE NEXT POTENTIAL
STORM SUNDAY-MONDAY.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...WINTER WEATHER ADVISORY UNTIL MIDNIGHT MST TONIGHT FOR COZ003-
017-018.
WINTER STORM WARNING UNTIL MIDNIGHT MST TONIGHT FOR COZ004-009-
010-012-013-019-022-023.
UT...NONE.
&&
$$
UPDATE...JAD
SHORT TERM...MPM
LONG TERM...MPM
AVIATION...JAD
Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
324 AM CST Sat Dec 27 2014
.SHORT TERM...(Today)
ISSUED AT 324 AM CST SAT DEC 27 2014
08z/2am surface analysis shows 1013mb low just north of KMLI, with
frontal boundary extending southwestward into Texas. Airmass ahead
of the front was initially quite dry as evidenced by the 00z KILX
upper air sounding: however, shallow low-level moisture has been on
the increase throughout the night. Surface dewpoints have reached
the middle 40s across central Illinois, while a plume of 50s
dewpoints is noted further upstream pushing into Arkansas. LAPS
soundings show this increasing moisture, with most local profiles
not saturated below 700mb. As low pressure tracks further
northeastward into Wisconsin, it will pull the cold front into the
area later this morning, then to the Indiana border by mid to late
afternoon. Continued moisture pooling along/ahead of the front will
result in increasingly deep moisture profiles, particularly across
the E/SE CWA this afternoon. HRRR suggests only scattered light
showers across much of the area this morning, then shows more
widespread precipitation developing along/east of I-57 this
afternoon. Think this solution makes sense as front gradually taps
into increasing amounts of Gulf moisture as it moves further east.
As a result, will carry chance PoPs across the western half of the
CWA throughout the day, with chance PoPs increasing to likely across
the E/SE this afternoon. With cold front passing through the area,
high temperatures will be achieved this morning, followed by brisk
westerly winds and falling temperatures later in the day. Due to
very mild current temps, have generally gone 2-4 degrees above MAV
guidance numbers. End result will be highs in the upper 40s and
lower 50s, with temps dropping into the 30s along/west of I-55
during the afternoon.
&&
.LONG TERM...(Tonight through Friday)
ISSUED AT 324 AM CST SAT DEC 27 2014
Cold front will slowly push eastward into the Ohio River Valley
tonight, with clouds and showers lingering across the E/SE through
at least the evening hours. NAM is fastest with the departure of
the precip, while GFS tends to keep it around through the entire
night. Based on slow forward movement of the front, have trended
toward the slower GFS. As a result, will maintain low chance PoPs
along/south of I-70 through the overnight hours. As temperatures
slowly fall into the lower to middle 30s across this area, any
lingering rain showers may mix with or change to light snow late.
Further northwest, skies will clear across the Illinois River
Valley, allowing lows to bottom out in the lower to middle 20s.
Sunshine and seasonably cool temps in the 30s will prevail Sunday
into Monday, before a surge of cold air arrives next week. Models
have been consistently showing strong 1050mb high building southward
out of western Canada into the central CONUS by Tuesday/Wednesday.
Weak synoptic lift along the leading edge of the cold air may be
enough to trigger a few flurries across the area Monday night, but
the main story will be the colder temps. High temps will remain in
the 20s Tuesday/Wednesday, while overnight lows dip into the single
digits and teens. After that, Canadian high pressure will gradually
slide east of the region, allowing a southern stream system to
approach by the end of the week. Model solutions vary with this
feature, so forecast confidence remains low at this point. ECMWF
aggressively brings precip northward into south-central Illinois as
early as Thursday night, while the GFS is about 12-18 hours
slower. Meanwhile, the GEM suggests the system may remain largely
southeast of the area across the Ohio River Valley. Given the
uncertainties, have opted to go with a dry forecast Thursday night,
and to slow precip onset on Friday. Have trimmed Friday PoPs to
just slight chance, with higher precip chances arriving Friday night
into Saturday. Think slower/colder is the way to go, especially
given the Canadian airmass that will initially be in place. End
result will be a chance of snow or a rain/snow mix mainly Friday
night into Saturday.
&&
.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
ISSUED AT 1149 PM CST FRI DEC 26 2014
Low pressure has moved NE along the cold front this evening,
reaching just west of Macomb at 0530z. Clouds are still at VFR
levels for another hour or two across our forecast area. The low
pressure will continue to advance NE up the front, passing over
Lake Michigan by Saturday morning. As the low departs, a cold
front extending south of the low will advance across our forecast
area. Upstream observations and forecast soundings point toward MVFR
clouds progressing over the terminal sites after midnight, with IFR
clouds accompanying the low as it moves over NW IL between 07z
and 12z. An initial push of rain will mainly affect the eastern
terminals of SPI/DEC/CMI/BMI through 09z. Additional rains are
expected to develop behind the initial line of showers, helping
drop cloud heights to IFR for several hours around sunrise.
Precipitation should diminish by Saturday afternoon, as the cold
front advances SE across the area and dry air aloft begins to
invade.
Winds will remain steady from the south at 9-14kt the rest of
tonight. The KILX VAD wind profiler shows that the low level jet
has already developed in central IL, with 35-40kt of winds at 2k
FT. Therefore we continued to include LLWS conditions for the
first 4-5 hours of this TAF period. Winds may back to the
southeast in the vicinity of the low toward PIA later tonight, but
then shift around to the SW then W during the day on Saturday
behind the cold front. Colder air will arrive on the increasing
W winds, with speeds of 13-16kt expected during the afternoon.
Winds will eventually veer to the NW Sat evening, as they diminish
below 10kt.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Barnes
LONG TERM...Barnes
AVIATION...Shimon
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
159 AM CST SAT DEC 27 2014
.SHORT TERM...
238 PM CST
THROUGH SUNDAY...
AN UPPER LEVEL RIDGE AXIS STRETCHES FROM CUBA UP THE ATLANTIC COAST
WITH THE SURFACE HIGH OVER THE SOUTHEAST U.S. THE UPPER LEVEL RIDGE
SHIFTS VERY LITTLE THROUGH SATURDAY. A NARROW SURFACE TROUGH EXTENDS
FROM TEXAS THROUGH THE UPPER PENINSULA OF MICHIGAN THIS AFTERNOON. A
CLOSED LOW WILL FORM OVER THE MID MISSISSIPPI VALLEY TONIGHT AND
MOVE OVER NORTHERN IL LATE TONIGHT/EARLY SATURDAY MORNING BEFORE
MAKING IT TO QUEBEC SATURDAY EVENING. WEAK HIGH PRESSURE THEN
SPREADS OVER THE CWA SUNDAY.
TEMPERATURES CONTINUE TO CLIMB INTO THE UPPER 40S TO LOWER 50S THIS
AFTERNOON WITH THE MAJORITY OF THE CWA RECEIVING AMPLE SUNSHINE.
CLOUD COVER WILL INCREASE THIS EVENING AND OVERNIGHT AS THE LOW
TAKES SHAPE AND MOVES IN. WITH THE SURFACE LOW PASSING RIGHT
OVERHEAD...THINKING FOG OR DRIZZLE IS PROBABLE ESPECIALLY WEST OF A
MCHENRY TO JOLIET LINE. ONLY HAVE PATCHY FOG IN THE FORECAST...BUT
COULD SEE VSBYS IN SOME AREAS DROP TO AROUND OR LESS THAN ONE MILE
DUE TO FOG OR DRIZZLE.
RAIN/DRIZZLE MOVES IN FROM SOUTHWEST TO NORTHEAST LATE THIS
EVENING...AND LATEST RAP AND HRRR GUIDANCE INDICATE THE PRECIP WILL
MOVE IN QUICKER THAN PREVIOUSLY THOUGHT. IT LOOKS LIKE A GOOD HIGH
POP/LOW QPF SITUATION. HAVE AN INCREASING POP TREND FROM MIDNIGHT
THROUGH THE EARLY MORNING HOURS AS THE LOW MOVES OVERHEAD. LIGHT
RAIN SHIFTS EAST SATURDAY AFTERNOON AS THE LOW CONTINUES NORTHEAST.
GUSTY WEST WINDS ARE EXPECTED TOMORROW WITH GUSTS AROUND 30 MPH IN
THE AFTERNOON. TEMPERATURES WILL ALSO BE FALLING FROM THE LATE
MORNING HOURS ON BEHIND THE LOWS COLD FRONT. HOWEVER AREAS ALONG AND
EAST OF I-55 WILL SEE HIGH TEMPS IN THE MID 40S TO AROUND 50. TEMPS
FALL INTO THE 20S SATURDAY NIGHT.
LIGHT WINDS SHIFT TO OUT OF THE NORTHWEST OR NORTH SUNDAY WITH DRY
CONDITIONS EXPECTED. THE COOLER AIR MASS WILL KEEP HIGH TEMPS IN THE
30S...BUT WE SHOULD SEE SOME SUNSHINE.
JEE
&&
.LONG TERM...
238 PM CST
SUNDAY NIGHT THROUGH FRIDAY...
AN UPPER LEVEL LOW WILL SHIFT EAST OVER NORTHERN QUEBEC
SUNDAY...AND A VORTICITY STREAMER ASSOCIATED WITH THE LOW PUSHES
SOUTH THROUGH THE REGION MONDAY. ANOTHER TROUGH AXIS SWINGS THROUGH
WEDNESDAY. AT THE SURFACE...WEAK HIGH PRESSURE REMAINS OVER THE
REGION SUNDAY NIGHT. A COLD FRONT COINCIDED WITH THE VORT STREAMER
PUSHES THROUGH THE REGION MONDAY. ARCTIC HIGH PRESSURE FOLLOWS THE
COLD FRONT...AND FINALLY SHIFTS SOUTH TO THE GULF STATES THURSDAY.
CLOUDS INCREASE SUNDAY NIGHT AHEAD OF THE COLD FRONT WITH LOW TEMPS
IN THE 20S. FLURRIES AND LIGHT SNOW ARE EXPECTED ALONG THE COLD
FRONT AS MODELS CONTINUE TO FEATURE A LITTLE QPF. COLD AIR MASSES
SUCH AS THIS ONE CAN USUALLY SQUEEZE OUT ANY MOISTURE LINGERING IN
THE AIR SO HAVE HIGHER POPS WHERE MODELS FEATURED QPF AND FLURRIES
ACROSS THE REST OF THE CWA. NOT EXPECTING MUCH SNOW ACCUMULATION IF
ANY AT ALL. NORTH WINDS DOWN THE LAKE MAY RESULT IN LAKE EFFECT
SNOW OVER NW INDIANA MONDAY NIGHT INTO TUESDAY. COULD SEE A COUPLE
TENTHS OF AN INCH OF SNOW.
THE BIGGER IMPACT WILL BE TEMPERATURES. HIGH TEMPS WILL BE IN THE
LOWER 30S MONDAY THEN ONLY IN THE UPPER TEENS TO MID 20S TUESDAY.
LOW TEMPS TUESDAY WILL BE VARY FROM THE SINGLE DIGITS OVER NORTH
CENTRAL IL TO AROUND 10 DEGREES OVER NORTHWEST INDIANA. BRISK NW
WINDS WILL CREATE BELOW ZERO WIND CHILLS TUESDAY NIGHT INTO WEDNESDAY
MORNING. THE WHOLE CWA FEELS THE CHILL WEDNESDAY WITH HIGH TEMPS
AROUND 20 DEGREES BUT GUSTY WEST WINDS WILL MAKE IT FEEL LIKE IT IS
IN THE SINGLE DIGITS.
THE CENTER OF THE HIGH SHIFTS SOUTH OF THE REGION THURSDAY ALLOWING
TEMPS TO WARM SLIGHTLY INTO THE UPPER 20S THURSDAY. LONG RANGE
GUIDANCE THEN FEATURES A LOW PRESSURE SYSTEM MOVING UP THE OHIO
RIVER VALLEY LATE NEXT WEEK. GUIDANCE HAS THE SYSTEM BRINGING US
SNOW OVER THE WEEKEND...SO WILL KEEP AN EYE ON THIS SYSTEM.
JEE
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* MVFR CIGS DEVELOPING OVERNIGHT POSSIBLY DROPPING TO IFR FOR A
TIME LATE TONIGHT/SATURDAY MORNING
* STRONG WEST WINDS LIKELY SATURDAY BEHIND COLD FRONT
* LINGERING MVFR CIGS POSSIBLE SAT AFTERNOON AND POSSIBLY SAT NIGHT
IZZI
//DISCUSSION...UPDATED 06Z...
LOW PRESSURE OVER EASTERN IOWA WILL TRACK NORTHEAST INTO
WISCONSIN. NOT SEEING A TON OF SUPPORT FOR IFR CIGS AND DRIZZLE
OVERNIGHT WITH NEAREST IFR CIGS STILL IN SOUTHERN MISSOURI...BUT
WAS RELUCTANT TO TOTALLY REMOVE IT GIVEN PRETTY STRONG SIGNAL IN
GUIDANCE FOR A TIME LATE TONIGHT/SAT MORNING. STILL COULD BE A
SHOWER OR TWO AROUND OVERNIGHT...BUT CHANCES LOOK LOW WITH MUCH IF
NOT ALL THE NIGHT NOW LOOKING TO BE DRY. COLD FRONT WILL SWEEP
ACROSS RFD MID-LATE MORNING AND CLEAR CHICAGO TERMINALS MIDDAY
WITH STRONG/GUSTY WESTERLY WINDS DEVELOPING IN THE WAKE OF THE
FRONT. COULD SEE A COUPLE GUSTS OVER 30KT BUT PREVAILING GUSTS IN
THE 23-28KT RANGE APPEARS PRETTY LIKELY UNTIL WINDS BEGIN TO
SUBSIDE AT SUNSET. MVFR CIGS WILL PROBABLY LINGER THROUGH THE
AFTERNOON AND PROBABLY INTO THE EVENING. COULD SEE MVFR CIGS BEGIN
TO SCATTER OUT AFTER MIDNIGHT SAT NIGHT AS LOW LEVEL FLOW BECOMES
MORE ANTICYCLONIC AND MODELS SUGGEST CONSIDERABLE DRYING.
IZZI
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* LOW CONFIDENCE IN CIGS
* MEDIUM-HIGH CONFIDENCE IN REMAINING FORECAST ELEMENTS
IZZI
//OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z...
SUNDAY...VFR. LIGHT W WINDS BECOMING NNE LATE.
MONDAY...SCHC -SHSN. MVFR PSBL. N TO NE WINDS.
TUESDAY...VFR. BREEZY NW WINDS.
WEDNESDAY AND THURSDAY...VFR. BREEZY SW WINDS AT TIMES.
MDB
&&
.MARINE...
158 AM CST
LOW OVER EASTERN IOWA WILL QUICKLY DEEPEN THROUGH THIS EVENING
AS IT TRACKS NORTHEAST ACROSS NORTHERN LAKE MICHIGAN AND
EVENTUALLY OFF INTO QUEBEC. DUE TO THE BRIEF BUT RAPID DEEPENING
AND COLD AIR ADVECTION THIS AFTERNOON THERE COULD BE A VERY BRIEF
WINDOW OF GALES BEHIND THE FRONT FOR AN HOUR OR TWO OVER SOUTHERN
PORTIONS OF THE LAKE. DURATION LOOKS TO BE TOO SHORT FOR GALE
WARNING THOUGH SO NO HEADLINE PLANNED FOR OPEN WATERS. WINDS/WAVES
LOOK TO RAPIDLY SUBSIDE TONIGHT INTO MONDAY BEFORE AN ARCTIC FRONT
BEGINS WORKING SOUTH DOWN THE LAKE MONDAY NIGHT INTO TUESDAY.
TIGHT GRADIENT BEHIND THE FRONT ALONG WITH VERY COLD AIR AND
UNSTABLE CONDITIONS SHOULD ALLOW FOR STRONG NORTHERLIES TO
DEVELOP...POSSIBLY TO NEAR GALE FORCE BEHIND THE FRONT. THAT
SHOULD MARK THE START OF AN ACTIVE PERIOD ON THE LAKE WITH LOW
PRESSURE TRACKING ACROSS CANADA MIDWEEK DRAGGING A FRONT ACROSS
THE LAKE AND TIGHTENING THE PRESSURE GRADIENT AND PROBABLY LEADING
TO A PERIOD OF WESTERLY GALES WEDNESDAY/EARLY THURSDAY TIME FRAME.
IZZI
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ744-LMZ745...10 AM SATURDAY TO 4 AM
SUNDAY.
SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743...10 AM
SATURDAY TO 10 PM SATURDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1140 PM CST FRI DEC 26 2014
.SHORT TERM...
238 PM CST
THROUGH SUNDAY...
AN UPPER LEVEL RIDGE AXIS STRETCHES FROM CUBA UP THE ATLANTIC COAST
WITH THE SURFACE HIGH OVER THE SOUTHEAST U.S. THE UPPER LEVEL RIDGE
SHIFTS VERY LITTLE THROUGH SATURDAY. A NARROW SURFACE TROUGH EXTENDS
FROM TEXAS THROUGH THE UPPER PENINSULA OF MICHIGAN THIS AFTERNOON. A
CLOSED LOW WILL FORM OVER THE MID MISSISSIPPI VALLEY TONIGHT AND
MOVE OVER NORTHERN IL LATE TONIGHT/EARLY SATURDAY MORNING BEFORE
MAKING IT TO QUEBEC SATURDAY EVENING. WEAK HIGH PRESSURE THEN
SPREADS OVER THE CWA SUNDAY.
TEMPERATURES CONTINUE TO CLIMB INTO THE UPPER 40S TO LOWER 50S THIS
AFTERNOON WITH THE MAJORITY OF THE CWA RECEIVING AMPLE SUNSHINE.
CLOUD COVER WILL INCREASE THIS EVENING AND OVERNIGHT AS THE LOW
TAKES SHAPE AND MOVES IN. WITH THE SURFACE LOW PASSING RIGHT
OVERHEAD...THINKING FOG OR DRIZZLE IS PROBABLE ESPECIALLY WEST OF A
MCHENRY TO JOLIET LINE. ONLY HAVE PATCHY FOG IN THE FORECAST...BUT
COULD SEE VSBYS IN SOME AREAS DROP TO AROUND OR LESS THAN ONE MILE
DUE TO FOG OR DRIZZLE.
RAIN/DRIZZLE MOVES IN FROM SOUTHWEST TO NORTHEAST LATE THIS
EVENING...AND LATEST RAP AND HRRR GUIDANCE INDICATE THE PRECIP WILL
MOVE IN QUICKER THAN PREVIOUSLY THOUGHT. IT LOOKS LIKE A GOOD HIGH
POP/LOW QPF SITUATION. HAVE AN INCREASING POP TREND FROM MIDNIGHT
THROUGH THE EARLY MORNING HOURS AS THE LOW MOVES OVERHEAD. LIGHT
RAIN SHIFTS EAST SATURDAY AFTERNOON AS THE LOW CONTINUES NORTHEAST.
GUSTY WEST WINDS ARE EXPECTED TOMORROW WITH GUSTS AROUND 30 MPH IN
THE AFTERNOON. TEMPERATURES WILL ALSO BE FALLING FROM THE LATE
MORNING HOURS ON BEHIND THE LOWS COLD FRONT. HOWEVER AREAS ALONG AND
EAST OF I-55 WILL SEE HIGH TEMPS IN THE MID 40S TO AROUND 50. TEMPS
FALL INTO THE 20S SATURDAY NIGHT.
LIGHT WINDS SHIFT TO OUT OF THE NORTHWEST OR NORTH SUNDAY WITH DRY
CONDITIONS EXPECTED. THE COOLER AIR MASS WILL KEEP HIGH TEMPS IN THE
30S...BUT WE SHOULD SEE SOME SUNSHINE.
JEE
&&
.LONG TERM...
238 PM CST
SUNDAY NIGHT THROUGH FRIDAY...
AN UPPER LEVEL LOW WILL SHIFT EAST OVER NORTHERN QUEBEC
SUNDAY...AND A VORTICITY STREAMER ASSOCIATED WITH THE LOW PUSHES
SOUTH THROUGH THE REGION MONDAY. ANOTHER TROUGH AXIS SWINGS THROUGH
WEDNESDAY. AT THE SURFACE...WEAK HIGH PRESSURE REMAINS OVER THE
REGION SUNDAY NIGHT. A COLD FRONT COINCIDED WITH THE VORT STREAMER
PUSHES THROUGH THE REGION MONDAY. ARCTIC HIGH PRESSURE FOLLOWS THE
COLD FRONT...AND FINALLY SHIFTS SOUTH TO THE GULF STATES THURSDAY.
CLOUDS INCREASE SUNDAY NIGHT AHEAD OF THE COLD FRONT WITH LOW TEMPS
IN THE 20S. FLURRIES AND LIGHT SNOW ARE EXPECTED ALONG THE COLD
FRONT AS MODELS CONTINUE TO FEATURE A LITTLE QPF. COLD AIR MASSES
SUCH AS THIS ONE CAN USUALLY SQUEEZE OUT ANY MOISTURE LINGERING IN
THE AIR SO HAVE HIGHER POPS WHERE MODELS FEATURED QPF AND FLURRIES
ACROSS THE REST OF THE CWA. NOT EXPECTING MUCH SNOW ACCUMULATION IF
ANY AT ALL. NORTH WINDS DOWN THE LAKE MAY RESULT IN LAKE EFFECT
SNOW OVER NW INDIANA MONDAY NIGHT INTO TUESDAY. COULD SEE A COUPLE
TENTHS OF AN INCH OF SNOW.
THE BIGGER IMPACT WILL BE TEMPERATURES. HIGH TEMPS WILL BE IN THE
LOWER 30S MONDAY THEN ONLY IN THE UPPER TEENS TO MID 20S TUESDAY.
LOW TEMPS TUESDAY WILL BE VARY FROM THE SINGLE DIGITS OVER NORTH
CENTRAL IL TO AROUND 10 DEGREES OVER NORTHWEST INDIANA. BRISK NW
WINDS WILL CREATE BELOW ZERO WIND CHILLS TUESDAY NIGHT INTO WEDNESDAY
MORNING. THE WHOLE CWA FEELS THE CHILL WEDNESDAY WITH HIGH TEMPS
AROUND 20 DEGREES BUT GUSTY WEST WINDS WILL MAKE IT FEEL LIKE IT IS
IN THE SINGLE DIGITS.
THE CENTER OF THE HIGH SHIFTS SOUTH OF THE REGION THURSDAY ALLOWING
TEMPS TO WARM SLIGHTLY INTO THE UPPER 20S THURSDAY. LONG RANGE
GUIDANCE THEN FEATURES A LOW PRESSURE SYSTEM MOVING UP THE OHIO
RIVER VALLEY LATE NEXT WEEK. GUIDANCE HAS THE SYSTEM BRINGING US
SNOW OVER THE WEEKEND...SO WILL KEEP AN EYE ON THIS SYSTEM.
JEE
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* MVFR CIGS DEVELOPING OVERNIGHT POSSIBLY DROPPING TO IFR FOR A
TIME LATE TONIGHT/SATURDAY MORNING
* STRONG WEST WINDS LIKELY SATURDAY BEHIND COLD FRONT
* LINGERING MVFR CIGS POSSIBLE SAT AFTERNOON AND POSSIBLY SAT NIGHT
IZZI
//DISCUSSION...UPDATED 06Z...
LOW PRESSURE OVER EASTERN IOWA WILL TRACK NORTHEAST INTO
WISCONSIN. NOT SEEING A TON OF SUPPORT FOR IFR CIGS AND DRIZZLE
OVERNIGHT WITH NEAREST IFR CIGS STILL IN SOUTHERN MISSOURI...BUT
WAS RELUCTANT TO TOTALLY REMOVE IT GIVEN PRETTY STRONG SIGNAL IN
GUIDANCE FOR A TIME LATE TONIGHT/SAT MORNING. STILL COULD BE A
SHOWER OR TWO AROUND OVERNIGHT...BUT CHANCES LOOK LOW WITH MUCH IF
NOT ALL THE NIGHT NOW LOOKING TO BE DRY. COLD FRONT WILL SWEEP
ACROSS RFD MID-LATE MORNING AND CLEAR CHICAGO TERMINALS MIDDAY
WITH STRONG/GUSTY WESTERLY WINDS DEVELOPING IN THE WAKE OF THE
FRONT. COULD SEE A COUPLE GUSTS OVER 30KT BUT PREVAILING GUSTS IN
THE 23-28KT RANGE APPEARS PRETTY LIKELY UNTIL WINDS BEGIN TO
SUBSIDE AT SUNSET. MVFR CIGS WILL PROBABLY LINGER THROUGH THE
AFTERNOON AND PROBABLY INTO THE EVENING. COULD SEE MVFR CIGS BEGIN
TO SCATTER OUT AFTER MIDNIGHT SAT NIGHT AS LOW LEVEL FLOW BECOMES
MORE ANTICYCLONIC AND MODELS SUGGEST CONSIDERABLE DRYING.
IZZI
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* LOW CONFIDENCE IN CIGS
* MEDIUM-HIGH CONFIDENCE IN REMAINING FORECAST ELEMENTS
IZZI
//OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z...
SUNDAY...VFR. LIGHT W WINDS BECOMING NNE LATE.
MONDAY...SCHC -SHSN. MVFR PSBL. N TO NE WINDS.
TUESDAY...VFR. BREEZY NW WINDS.
WEDNESDAY AND THURSDAY...VFR. BREEZY SW WINDS AT TIMES.
MDB
&&
.MARINE...
324 PM CST
A TROUGH OF LOW PRESSURE MOVING ACROSS THE REGION IS HELPING TO
PROVIDE SIGNIFICANT DIFFERENCES WITH WIND SPEED AND DIRECTION
ACROSS THE ENTIRE LAKE THIS AFTERNOON...AND EXPECT THESE
DIFFERENCES TO REMAIN IN PLACE TONIGHT INTO SATURDAY MORNING.
WHILE SOUTHERLY FLOW REMAINS IN PLACE OVER THE SOUTHERN HALF OF
THE LAKE...SOUTHERLY WINDS OVER THE NORTHERN HALF ARE ALREADY
SLOWLY BECOMING MORE NORTHERLY AS THIS TROUGH MOVES ACROSS THE
LAKE. THIS TREND WILL CONTINUE OVER THE NORTHERN HALF TONIGHT WITH
MORE NORTHERLY WINDS EXPECTED LATER TONIGHT...WHILE SOUTHERLY
WINDS PERSIST OVER THE SOUTHERN HALF. NEW LOW PRESSURE WILL THEN
DEVELOP ALONG THIS TROUGH/BOUNDARY EARLY SATURDAY MORNING AND MOVE
ACROSS THE LAKE SATURDAY. EXPECT SPEEDS TO INCREASE DURING THE DAY
AS WINDS BECOME MORE WESTERLY IN THE AFTERNOON...AND THEN
NORTHWEST IN THE EVENING. EXPECT SPEEDS TO THEN DIMINISH SATURDAY
NIGHT INTO SUNDAY AS THIS LOW DEPARTS AND HIGH PRESSURE BUILDS
ACROSS THE REGION.
RODRIGUEZ
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ744-LMZ745...10 AM SATURDAY TO 4 AM
SUNDAY.
SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743...10 AM
SATURDAY TO 10 PM SATURDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
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AREA FORECAST DISCUSSION
NWS DODGE CITY KS
310 AM CST SAT DEC 27 2014
...UPDATED LONG TERM SECTION...
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 258 PM CST FRI DEC 26 2014
THE NAM MODEL SEEMED TO OUTPERFORM THE HRRR WITH RESPECT TO
PRECIP PLACEMENT LATE THIS MORNING AND EARLY AFTERNOON. THE MODEL
WILL CONTINUE TO BE USED AS A GUIDE IN COMBINATION WITH CURRENT
TRENDS TO PLACE POPS AND QPF/SNOW AMOUNTS FOR THE REST
AFTERNOON/EVENING. A DECISION WILL NEED TO BE MADE WHETHER TO
EXTEND EITHER IN TIME AND AREAL COVERAGE OR DROP THE ADVISORY
ALTOGETHER AT 4 PM. AT THIS TIME, EXTENSION DOES NOT APPEAR TO BE
LIKELY. THE NAM INDICATED AN INTSENSIFICATION OF FRONTOGENESIS IN
THE MID TO LATE AFTERNOON, HOWEVER IT IS ASSOCIATED WITH NON
FAVORABLE AGEOSTROPHIC FLOW FOR VERTICAL MOTION. ONCE THE SNOW
BEGINS TO WIND DOWN FROM THE DISSIPATION OF VERTICAL MOTION, CLOUD
CEILING HEIGHTS WILL BEGIN TO INCREASE FROM WEST TO EAST THIS
EVENING. FOG SHOULD NOT BE A BIG CONCERN HEADING INTO THE
OVERNIGHT AS SURFACE BOUNDARY LAYER AIR SEES A BUMP IN DEW POINT
TEMPERATURES (WHICH THE NAM SEEMS TO REFLECT), AS SURFACE WINDS
WILL BE WELL ENOUGH MIXED AND SLIGHTLY DOWNSLOPED.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 310 AM CST SAT DEC 27 2014
MOSTLY CLEAR SKIES ARE EXPECTED ON SUNDAY WITH WESTERLY FLOW ALOFT
AND DRY CONDITIONS IN PLACE IN THE MID LEVELS OF THE ATMOSPHERE.
SOUTHWEST WINDS WILL BE FELT AT THE SURFACE WITH A TROUGH OF LOW
PRESSURE POSITIONED ACROSS EASTERN COLORADO. AN UPPER LEVEL TROUGH
THEN DEEPENS ACROSS THE WESTERN UNITED STATES MONDAY. THIS WILL
HELP PUSH A COLD FRONT AT THE SURFACE SOUTH ACROSS NEBRASKA AND
INTO WESTERN KANSAS IN THE AFTERNOON. THE ATMOSPHERE WILL BECOME
SATURATED BEHIND THIS FRONT INCREASING CLOUDINESS. A FEW SNOW
SHOWERS MAY FORM IN THE LATE AFTERNOON INTO OVERNIGHT PERIOD WITH
DECREASING CHANCES ON TUESDAY. MOSTLY CLOUDY SKIES CONTINUE
THROUGH TUESDAY NIGHT WITH NORTHERLY WINDS AND WELL BELOW NORMAL
TEMPERATURES. PARTLY CLOUDY SKIES AND DRY CONDITIONS ARE EXPECTED
MID WEEK AS A DOME OF HIGH PRESSURE MOVES SOUTHWARD ACROSS THE
CENTRAL PLAINS. THE NEXT CHANCE OF PRECIPITATION IS EXPECTED LATE
WEEK INTO THIS WEEKEND AS THE AFOREMENTIONED UPPER LEVEL TROUGH
DEEPENS INTO A LOW AND EJECTS EASTWARD TOWARDS THE PLAINS. AS FOR
TEMPERATURES, HIGHS SUNDAY LOOK TO REACH INTO THE 30S WITH LOWS IN
THE UPPER TEENS AND LOWER 20S. HIGHS MONDAY LOOK TO RANGE FROM
AROUND 20 DEGREES ACROSS WEST CENTRAL KANSAS TO MID 30S ACROSS
SOUTH CENTRAL KANSAS. THIS IS DUE TO THE COLD FRONT MOVING THROUGH
THE AREA IN THE AFTERNOON. HIGHS IN THE TEENS ARE THEN ANTICIPATED
TUESDAY WITH LOWS DIPPING INTO THE SINGLE DIGITS AND POSSIBLY EVEN
BELOW ZERO ACROSS WEST CENTRAL KANSAS BY SUNRISE WEDNESDAY.
TEMPERATURES THEN SLOWLY REBOUND TO THE 30S BY FRIDAY WITH LOWS
INCREASING INTO THE TEENS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1128 PM CST FRI DEC 26 2014
A VERY QUIET PATTERN WILL DOMINATE WESTERN AND CENTRAL KANSAS THE
REMAINDER OF TONIGHT AND LASTING THROUGH SATURDAY. SPECIFICALLY,
THE UPPER TROUGH BRINGING SNOW AND IFR CEILINGS ON FRIDAY, WILL
SHIFT SLOWLY EAST ACROSS THE GREAT PLAINS ON SATURDAY. THIS WILL
ALLOW SURFACE HIGH PRESSURE TO BUILD INTO THE CENTRAL PLAINS WITH
ONLY SOME SCATTERED VFR CLOUD COVER EXPECTED. OTHERWISE, NORTHWEST
WINDS AROUND 10 KT WILL TURN LIGHT AND VARIABLE BY SUNSET ON
SATURDAY WHILE THE VISIBILITY IS UNLIMITED.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 32 14 38 17 / 0 0 0 0
GCK 32 12 37 15 / 0 0 0 0
EHA 31 16 40 17 / 0 0 0 0
LBL 33 14 39 18 / 0 0 0 0
HYS 30 14 37 17 / 0 0 0 0
P28 36 17 41 21 / 0 0 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...RUSSELL
LONG TERM...HOVORKA_42
AVIATION...AJOHNSON
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1128 PM CST FRI DEC 26 2014
...UPDATED AVIATION SECTION...
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 258 PM CST FRI DEC 26 2014
THE NAM MODEL SEEMED TO OUTPERFORM THE HRRR WITH RESPECT TO
PRECIP PLACEMENT LATE THIS MORNING AND EARLY AFTERNOON. THE MODEL
WILL CONTINUE TO BE USED AS A GUIDE IN COMBINATION WITH CURRENT
TRENDS TO PLACE POPS AND QPF/SNOW AMOUNTS FOR THE REST
AFTERNOON/EVENING. A DECISION WILL NEED TO BE MADE WHETHER TO
EXTEND EITHER IN TIME AND AREAL COVERAGE OR DROP THE ADVISORY
ALTOGETHER AT 4 PM. AT THIS TIME, EXTENSION DOES NOT APPEAR TO BE
LIKELY. THE NAM INDICATED AN INTSENSIFICATION OF FRONTOGENESIS IN
THE MID TO LATE AFTERNOON, HOWEVER IT IS ASSOCIATED WITH NON
FAVORABLE AGEOSTROPHIC FLOW FOR VERTICAL MOTION. ONCE THE SNOW
BEGINS TO WIND DOWN FROM THE DISSIPATION OF VERTICAL MOTION, CLOUD
CEILING HEIGHTS WILL BEGIN TO INCREASE FROM WEST TO EAST THIS
EVENING. FOG SHOULD NOT BE A BIG CONCERN HEADING INTO THE
OVERNIGHT AS SURFACE BOUNDARY LAYER AIR SEES A BUMP IN DEW POINT
TEMPERATURES (WHICH THE NAM SEEMS TO REFLECT), AS SURFACE WINDS
WILL BE WELL ENOUGH MIXED AND SLIGHTLY DOWNSLOPED.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 327 PM CST FRI DEC 26 2014
MEDIUM RANGE MODELS INDICATE A POSITIVELY TILTED UPPER LEVEL TROUGH
OF LOW PRESSURE SHIFTING EASTWARD OUT OF THE DESERT SOUTHWEST INTO
THE SOUTH PLAINS SUNDAY BRINGING ABOUT A WESTERLY FLOW ALOFT TO THE
WESTERN HIGH PLAINS. A WEAKENING FLOW ALOFT COMBINED WITH A LACK OF
LOW/MID LEVEL MOISTURE WILL RESULT IN DRY CONDITIONS PREVAILING
ACROSS WESTERN KANSAS THROUGH LATE MONDAY MORNING. PRECIP CHANCES
WILL INCREASE A LITTLE MONDAY AFTERNOON AS DEEPENING UPPER LEVEL
TROUGH DROPS SOUTHWARD ACROSS THE PACIFIC NORTHWEST SETTING UP A
DIFLUENT FLOW ALOFT ACROSS THE WESTERN HIGH PLAINS. THIS WILL
COINCIDE WITH ANOTHER STRONG COLD FRONT PUSHING SOUTHWARD ACROSS
WESTERN KANSAS AS THE FLOW ALOFT STRENGTHENS AFTER EXITING THE
TROUGH AXIS OUT WEST. AS A RESULT, SNOW IS LIKELY TO DEVELOP
ACROSS THE HIGH PLAINS OF COLORADO MONDAY WITH THE POTENTIAL FOR
SNOW SPREADING EASTWARD INTO PORTIONS OF WESTERN KANSAS FROM
MONDAY AFTERNOON THROUGH EARLY TUESDAY MORNING. ALTHOUGH IT IS TOO
EARLY TO DETERMINE SNOW AMOUNT POTENTIAL, WEAK QPF SIGNALS SUGGEST
LIGHTER AMOUNTS, IF ANY.
ALTHOUGH REBOUNDING SOMEWHAT, TEMPERATURES WILL REMAIN BELOW NORMAL
SUNDAY WITH COLDER AIR SLOW TO ERODE AS A LEE SIDE TROUGH OF LOW
PRESSURE DEVELOPS ACROSS EASTERN COLORADO. THE GFS/ECMWF SHOW THE
H85 0C ISOTHERM BEGINNING TO EDGE BACK TO THE NORTH BUT REMAINING
WELL SOUTH OF CENTRAL AND MUCH OF SOUTHWEST KANSAS. EVEN WITH
DECREASED CLOUD COVER EXPECTED, LOOK FOR HIGHS ONLY UP INTO THE
30S(F) SUNDAY AFTERNOON WITH NEAR 40F STILL A POSSIBILITY CLOSER TO
THE OKLAHOMA BORDER. THE GFS AND ECMWF CONTINUE TO PROJECT A
STRONG ARCTIC COLD FRONT PUSHING THROUGH WESTERN KANSAS MONDAY
BRINGING ANOTHER ROUND OF COLD AIR SURGING SOUTHWARD INTO THE
REGION EARLY NEXT WEEK. HIGHS COULD BE AS LOW AS THE TEENS(F)
TUESDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1128 PM CST FRI DEC 26 2014
A VERY QUIET PATTERN WILL DOMINATE WESTERN AND CENTRAL KANSAS THE
REMAINDER OF TONIGHT AND LASTING THROUGH SATURDAY. SPECIFICALLY,
THE UPPER TROUGH BRINGING SNOW AND IFR CEILINGS ON FRIDAY, WILL
SHIFT SLOWLY EAST ACROSS THE GREAT PLAINS ON SATURDAY. THIS WILL
ALLOW SURFACE HIGH PRESSURE TO BUILD INTO THE CENTRAL PLAINS WITH
ONLY SOME SCATTERED VFR CLOUD COVER EXPECTED. OTHERWISE, NORTHWEST
WINDS AROUND 10 KT WILL TURN LIGHT AND VARIABLE BY SUNSET ON
SATURDAY WHILE THE VISIBILITY IS UNLIMITED.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 18 32 16 38 / 20 0 0 0
GCK 12 31 15 36 / 10 0 0 0
EHA 13 32 16 39 / 10 0 0 0
LBL 16 34 15 39 / 10 0 0 0
HYS 16 29 15 36 / 20 0 0 0
P28 21 38 18 41 / 10 0 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...RUSSELL
LONG TERM...JJOHNSON
AVIATION...AJOHNSON
AREA FORECAST DISCUSSION
NWS JACKSON KY
339 AM EST SAT DEC 27 2014
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 337 AM EST SAT DEC 27 2014
MODELS ARE IN GOOD AGREEMENT THROUGH THE SHORT TERM...THOUGH THEY
WERE LATE IN PICKING UP ON POTENTIAL SHOWER ACTIVITY CURRENTLY MOVING
EAST OF OUR AREA. HRRR IS PICKING UP ON ADDITIONAL SHOWER ACTIVITY
FAR TO OUR WEST...OVER THE WESTERN END OF THE COMMONWEALTH AND DOES
BRING THAT EASTWARD TOWARDS OUR AREA. BUT ACTIVITY SUPPOSEDLY WEAKENS
AND DISSIPATES BY THE TIME IT REACHES OUR CWA AROUND MID MORNING.
OTHER OPERATIONAL MODELS TEND TO SUPPORT THIS SCENARIO THOUGH WILL
HAVE TO WATCH THIS CAREFULLY THROUGH THE MORNING IN CASE MODELS WIND
UP HANDLING THIS POORLY AS WELL AND POPS NEED TO BE RAMPED UP MORE
QUICKLY THROUGH THE DAY.
MID/UPPER LEVEL RIDGE...CENTERED OVER CUBA IS RETREATING EASTWARD
WITH APPROACH OF SHORT WAVE ENERGY AND TROUGH LIFTING OUT OF THE
WESTERN GREAT BASIN...SOUTHWEST CONUS. AT THE SFC...HIGH PRESSURE
CENTERED OVER THE CENTRAL ATLANTIC COASTAL REGION IS ALSO BEGINNING
TO RETREAT EASTWARD. CONTINUED MOVEMENT OF MID/UPPER LEVEL TROUGH
OUT OF THE WESTERN CONUS WILL INDUCE A SERIES OF SFC LOWS...THE FIRST
DEVELOPING OVER THE EASTERN PLAINS AND MOVING THROUGH THE GREAT
LAKES BY LATE TODAY. THIS FIRST LOW WILL DRAG A SFC COLD FRONTAL
BOUNDARY INTO THE OHIO VALLEY TONIGHT...REACHING OUR CWA BY SUNDAY
MORNING. A SECOND LOW WILL DEVELOP MUCH FURTHER SOUTH OVER THE
SOUTHERN MISSISSIPPI VALLEY REGION AND TRACK NORTHEAST ALONG THE
FRONT AS THE SFC BOUNDARY PUSHES ACROSS THE APPALACHIANS SUNDAY
MORNING. THIS WILL KEEP OUR WEATHER WET THROUGH TO THE END OF THE
SHORT TERM.
FOR SENSIBLE WEATHER...WEAK IMPULSE RESPONSIBLE FOR SPRINKLES AND
VERY ISOLATED SHOWER ACTIVITY OVER OUR AREA EARLY THIS MORNING IS
EXITING TO OUR EAST...WITH CORRESPONDING ACTIVITY EXITING AS WELL.
MID AND HIGH LEVEL CLOUDS WILL CONTINUE TO THICKEN AND LOWER WITH
TIME...THOUGH WE COULD SEE A FEW BREAKS AT TIMES THROUGH THE DAY.
COULD SEE SOME ADDITIONAL SPRINKLES ACROSS PORTIONS OF OUR AREA BY
MID MORNING TO NOON AS THE SECOND AREA OF ACTIVITY TO OUR FAR WEST
WEAKENS WHILE MOVING EASTWARD. OUR MAIN EVENT...RAIN ASSOCIATED WITH
THE APPROACHING COLD FRONTAL SYSTEM WILL BEGIN TO OVERSPREAD OUR AREA
FROM THE WEST LATE THIS AFTERNOON. RAIN WILL INCREASE THROUGH THE
OVERNIGHT AND LINGER THROUGH THE DAY SUNDAY AS THE AFOREMENTIONED
SECOND WAVE OF LOW PRESSURE RIDES UP INTO THE SOUTHERN APPALACHIANS.
INCREASED POPS FOR TONIGHT AND SUNDAY FOLLOWING THE LEAD OF GUIDANCE.
TEMPERATURES CONTINUE TO MODERATE WITH A RELATIVELY LIMITED DIURNAL
RANGE OVER THE NEXT 18 TO 24 HOURS DUE TO INCREASED CLOUD COVER. ALSO
PREFERRED TO GO WITH A NON DIURNAL TEMP TREND THROUGH THE DAY SUNDAY
AS COLDER AIR FILTERS IN BEHIND THE SFC COLD FRONT.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 337 AM EST SAT DEC 27 2014
FRONTAL BOUNDARY AND WAVES OF LOW PRESSURE WILL SLOWLY PUSH EAST OF
THE CWA MOVING INTO THE LONG TERM PERIOD. SLOWLY LESSEN POPS
OVERNIGHT SUNDAY INTO MONDAY AS BETTER LIFT MOVES EAST OF THE REGION.
AFTER THIS THERE IS A UPPER LEVEL DISTURBANCE THAT MOVES ACROSS THE
REGION GOING INTO TUESDAY THIS WILL BRING SOME CLOUD COVER TO THE
REGION. OTHER THAN THAT NOT EXPECTING MUCH IN THE WAY OF PRECIP AS
HIGH PRESSURE CONTINUES BUILDS EAST WEDNESDAY WITH SKIES CLEARING OUT
THROUGH THE DAY. COOLER AIR WILL FILTER INTO THE REGION GIVING WAY TO
HIGHS IN THE LOW TO MID 30S FOR HIGHS ON WEDNESDAY. CONTINUED
CLEARING SKIES AND BUILDING HIGH PRESSURE WILL GIVE WAY TO GOOD
RADIATIONAL COOLING WEDNESDAY NIGHT WITH LOWS IN THE UPPER TEENS TO
LOWER 20S ACROSS THE REGION. MORE UNCERTAINTY IN THE MODELS EXIST AS
WE MOVE INTO THE LONGER RANGE PORTION OF THE LONG TERM. HIGH PRESSURE
IS EXPECTED TO SLOWLY MOVE EAST AS WE MOVE INTO THURSDAY. RIGHT NOW
THURSDAY LOOKS DRY...HOWEVER A LOW PRESSURE SYSTEM IS EXPECT TO
DEVELOP ACROSS THE SOUTHERN PLAINS THURSDAY/FRIDAY AS UPPER LEVEL LOW
EJECTS OUT OF THE FOUR CORNERS REGION. MOISTURE WILL SLOWLY SPREAD
NORTH AND EAST TOWARD THE OHIO VALLEY AS WE MOVE INTO FRIDAY. TIMING
ON THE PRECIP DIFFER AT THIS POINT WITH ECMWF MOST PROGRESSIVE. GIVEN
THE UNCERTAINTY DID STICK REASONABLY CLOSE TO THE MODEL BLEND AND
TRYING TO KEEP SOME CONSISTENCY/COLLABORATION. THIS DOES GIVE WAY TO
SLIGHT POPS THURSDAY NIGHT AND CHANCE POPS FRIDAY. GIVEN COOLER TEMPS
ONSET OF POPS WOULD BE A SNOW OR RAIN/SNOW MIX THURSDAY NIGHT INTO
EARLY FRIDAY. HOWEVER RIGHT NOW CONFIDENCE REMAINS LOW GIVEN MODEL
DIVERGENCE DURING THIS PERIOD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 108 AM EST SAT DEC 27 2014
LOOK FOR VFR CONDITIONS THROUGH THE ENTIRE FORECAST PERIOD. RADAR IS
PICKING UP ON A RATHER LARGE AREA OF LIGHT ECHOS TONIGHT. HAVE EVEN
SEEN SOME -IP/-RA HERE AT JKL AS ONE CELL INTENSIFIED SUDDENLY. BUT
THE BULK OF THIS ACTIVITY IS VIRGA AND AS SUCH DID NOT MENTION ANY
WEATHER AT ANY OF OUR TERMINALS. ALSO EXPECT THIS ACTIVITY TO WANE
AS WE PROGRESS THROUGH THE EARLY MORNING HOURS. ADDITIONAL SHOWERS
ASSOCIATED WITH AN APPROACHING COLD FRONTAL SYSTEM WILL DEVELOP
DURING THE LAST FEW HOURS OF THE FORECAST. CIGS AND VSBYS WILL DROP
THEREAFTER...JUST BEYOND THE FORECAST WINDOW. WINDS WILL RUN LESS
THAN 10 KTS THROUGH THE PERIOD...AND GENERALLY FROM THE S/SW.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...RAY
LONG TERM...DJ
AVIATION...RAY
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
328 AM EST SAT DEC 27 2014
LATEST UPDATE...
SYNOPSIS/SHORT TERM/LONG TERM/HYDRO/MARINE
.SYNOPSIS...
ISSUED AT 328 AM EST SAT DEC 27 2014
WE WILL SEE THE LAST OF THE MILD WEATHER TODAY WITH INTERMITTENT
LIGHT RAIN AND DRIZZLE. COLDER AIR MOVES IN TONIGHT WITH A SECOND
WAVE OF ARCTIC AIR MONDAY NIGHT THROUGH WEDNESDAY. HIGHS ONLY IN THE 20S
ARE EXPECTED DURING THE MIDDLE PORTION OF THE WEEK AND MAY
STRUGGLE TO REACH 20 DEGREES ON WEDNESDAY...ESPECIALLY NORTH OF GRAND
RAPIDS. SNOW ACCUMULATIONS ALSO APPEAR POSSIBLE MONDAY NIGHT INTO
WEDNESDAY. TEMPERATURES WILL MODERATE SLIGHTLY TOWARD THE END OF
THE WORK WEEK BEFORE ANOTHER SURGE OF ARCTIC AIR NEXT WEEKEND.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 328 AM EST SAT DEC 27 2014
TEMPERATURES HAD RISEN INTO THE MID 40S MAINLY ALONG AND SOUTH OF
I-96 AS OF THIS WRITING. TEMPS AND DEWPOINTS WILL CONTINUE TO
CREEP UP THIS MORNING. 06Z HRRR CONTINUES TO INDICATE PERIODS OF
LIGHT RAIN AND DRIZZLE TODAY...THE FIRST AFTER 10Z OR SO.
THE WEAK SURFACE LOW IS FORECAST TO DEEPEN TO AROUND 1008 MB OVER
NORTHERN LOWER MI BY 18Z. THE COLD FRONT THEN MOVES THROUGH
FOLLOWED BY A VEERING OF THE WINDS DURING THE AFTERNOON. SURFACE
TEMPS ARE EXPECTED TO REMAIN ABOVE FREEZING AT 00Z THIS
EVENING...AND MOISTURE QUICKLY BAILS AFTER 00Z. THE ONSHORE FLOW
IS ALSO SLIGHTLY DIVERGENT. FORECAST THINKING HAS NOT
CHANGED...LITTLE IF ANY SNOW TONIGHT.
QUIET WEATHER EXPECTED ON SUNDAY. A VERY STRONG 1057 MB HIGH
DEVELOPS OVER WESTERN CANADA AND AN EXTENSION OF THIS HIGH
PRESSURE SYSTEM TURNS LOW LEVEL FLOW NORTHEASTERLY BY MONDAY.
THINKING PARTLY SUNNY FOR NOW WITH HIGHS IN THE LOW TO MID 30S.
.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 328 AM EST SAT DEC 27 2014
MODELS ARE IN DECENT AGREEMENT IN SHOWING A DEEPENING UPPER LOW OVER
HUDSON BAY AS WE HEAD THROUGH THE EXTENDED PERIOD. THIS WILL RESULT
IN A COLDER THAN NORMAL PERIOD THROUGH THE LONG TERM PERIOD.
THE ARCTIC AIR WILL ARRIVE IN WAVES. MONDAY NIGHT THROUGH WEDNESDAY
WILL FEATURE COLD AIR ADVECTION. THE LOW LEVEL THERMAL TROUGH
PUSHES THROUGH ON WEDNESDAY. HIGHS ON WEDNESDAY MAY STRUGGLE TO
REACH 20 DEGREES...ESPECIALLY NORTH OF GRAND RAPIDS. WIND WILL
ACCOMPANY THIS ARCTIC AIRMASS AND SUB ZERO WIND CHILLS WILL OCCUR AT
TIMES. ALSO MODELS HAVE BEEN TRENDING TOWARD MORE MOISTURE IN THE
DGZ MON NIGHT INTO WED. THUS WE MAY END UP WITH SOME
ACCUMULATIONS. I DID TREND POPS UPWARD BASED ON THE TRENDS.
TEMPERATURES ARE LIKELY TO MODERATE SLIGHTLY THURSDAY INTO FRIDAY AS
WARM AIR ADVECTION DEVELOPS ON THE BACKSIDE OF THE DEPARTING
HIGH. THEY ARE EXPECTED TO STILL AVERAGE OUT BELOW NORMAL.
ANOTHER SURGE OF ARCTIC AIR WILL LIKELY PUSH IN OVER NEXT WEEKEND.
THIS IS WHEN THE SOUTHERN ROCKIES LOW KICKS OUT INTO THE PLAINS AND
TRACKS TO THE CENTRAL APPALACHIANS. AS THIS WAVE TRACKS EAST...AN
IMPRESSIVE SURGE OF ARCTIC AIR SINKS SOUTH THROUGH THE GREAT LAKES
REGION. THERE IS A RISK FOR SNOW ASSOCIATED WITH THE ARRIVAL OF
THIS NEXT REINFORCING SHOT OF ARCTIC AIR. OVERALL MODELS HAVE COME
INTO BETTER AGREEMENT OF THE TIMING AND DURATION OF THIS NEXT ARCTIC
AIRMASS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1157 PM EST FRI DEC 26 2014
CEILINGS WILL SLOWLY LOWER TO IFR BY MORNING AND PERIOD OF LIGHT
RAIN OR DRIZZLE WILL ALSO DEVELOP BY THEN ALSO LOWERING
VISIBILITIES TO IFR. THE FRONT WILL COME THROUGH DURING THE
AFTERNOON AND WILL END THE PRECIPITATION AND IMPROVE VISIBILITIES.
CEILINGS WILL ONLY SLOWLY LIFT DURING THE EVENING.
&&
.MARINE...
ISSUED AT 328 AM EST SAT DEC 27 2014
A SMALL CRAFT ADVISORY HAS BEEN ISSUED FOR 11 AM TODAY THROUGH 11
AM SUNDAY. AS THE SURFACE LOW APPROACHES...SOUTHERLY WINDS WILL
INCREASE TO 15 TO 25 KNOTS TODAY. WINDS WILL VEER WEST TO 30 KNOTS
LATE THIS AFTERNOON AND EVENING. WAVES WILL BUILD TO 4 TO 8 FEET
NORTH OF HOLLAND AND 3 TO 5 FEET SOUTH OF HOLLAND. WEST WINDS WILL
VEER NORTHWESTERLY TONIGHT.
&&
.HYDROLOGY...
ISSUED AT 328 AM EST SAT DEC 27 2014
AROUND A TENTH OF AN INCH OR LESS OF RAINFALL IS EXPECTED
TODAY...WITH SLIGHTLY HIGHER AMOUNTS POSSIBLE TOWARD LUDINGTON.
THIS LIGHT RAINFALL IS NOT EXPECTED TO HAVE A SIGNIFICANT IMPACT
ON RIVERS. ALL RIVER FLOOD ADVISORIES HAVE BEEN CANCELED.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY FROM 11 AM THIS MORNING TO 11 AM EST SUNDAY
FOR LMZ844>849.
&&
$$
SYNOPSIS...EBW
SHORT TERM...EBW
LONG TERM...MJS
AVIATION...WDM
HYDROLOGY...EBW
MARINE...EBW
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1158 PM EST FRI DEC 26 2014
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 330 PM EST FRI DEC 26 2014
ONE MORE UNSEASONABLY MILD DAY IS IN STORE FOR SATURDAY AS A LOW
PRESSURE SYSTEM OVER MISSOURI TRACKS NORTHEAST THROUGH WISCONSIN AND
NORTHERN MICHIGAN.
MOISTURE STREAMING NORTH AHEAD OF THIS SYSTEM WILL BRING CLOUDS AND
OCCASIONAL LIGHT RAIN OR DRIZZLE BEGINNING LATE TONIGHT AND
CONTINUING THROUGH SATURDAY. THE RAIN MAY MIX WITH A LITTLE LIGHT
SNOW SATURDAY NIGHT BEFORE ENDING AS A COLD FRONT PASSES THROUGH.
WE WILL SEE SOME CHILLY AIR AND LIGHT LAKE EFFECT SNOW SHOWERS
ARRIVE THIS WEEK WITH HIGHS MAINLY IN THE 20S. NO SIGNIFICANT SNOW
ACCUMULATIONS ARE EXPECTED AT THIS TIME.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 330 PM EST FRI DEC 26 2014
NO MAJOR CHANGES IN THINKING TO THE GOING FORECAST. WIDESPREAD LOW
CLOUDS DEVELOP LATER THIS EVENING AS SFC DEW POINTS AROUND 40 STREAM
IN FROM THE SOUTHWEST. LATEST RUNS OF THE HRRR SHOW SCATTERED LIGHT
CONVECTIVE LOOKING RAIN SHOWERS DEVELOPING THIS EVENING ACROSS
MISSOURI AND ILLINOIS. THESE SHOULD WILL LIKELY TRACK INTO THE AREA
FROM THE SOUTHWEST OR DEVELOP OVERHEAD OVERNIGHT AND PERSIST
SATURDAY WITHIN THE WARM ADVECTION ZONE AHEAD OF THE APPROACHING SFC
LOW AND COLD FRONT. IN ADDITION TO THE CONVECTIVE RAIN SHOWERS...
SOME PATCHY DRIZZLE MAY BE SQUEEZED OUT OF THE LOW CLOUDS AT TIMES
LATE TONIGHT AND SATURDAY.
DEEPER MOISTURE MOVES EAST OF THE AREA AFTER 00Z SUNDAY ABOUT THE
TIME THE COLDER AIR IS ARRIVING. PRECIPITATION BEHIND THE SFC COLD
FRONT SHOULD TREND TOWARD JUST SOME VERY LIGHT MIXED RAIN AND SNOW
SHOWERS. NO SNOW ACCUMULATIONS EXPECTED LATE SATURDAY NIGHT INTO
EARLY SUNDAY DUE TO VERY SHALLOW MOISTURE PROFILES AND QUESTIONABLE
DGZ SATURATION. ADDITIONALLY...SURFACE RIDGING/ANTICYCLONIC FLOW IS
QUICK TO BUILD IN WHICH ACTUALLY LEADS TO DECENT PROSPECT FOR
SUNSHINE DEVELOPING SUNDAY AFTERNOON.
.LONG TERM...(MONDAY THROUGH FRIDAY)
ISSUED AT 330 PM EST FRI DEC 26 2014
WE CONTINUE TO EXPECT A TREND TOWARD COLDER WEATHER IN THE LONG TERM
WITH CHCS OF SNOW SHOWERS THROUGH THE PERIOD. SNOW ACCUMULATIONS DO
NOT LOOK TO BE ANYTHING SIGNIFICANT IN THE FCST PERIOD FOR NOW. WE
WILL CONTINUE TO MONITOR THIS POTENTIAL AS IT WOULD NOT TAKE MAJOR
CHANGES TO BRING A BETTER POTENTIAL OF LAKE EFFECT.
THE CHC OF SNOW FOR SW LOWER ON MON DOES NOT LOOK REAL GOOD AT THIS
TIME. A SHORT WAVE TROUGH WILL BE MOVING INTO THE GREAT LAKES REGION
FROM THE WNW ON MON. HOWEVER A STRONG 1050+ MB RIDGE TO OUR WEST
WILL BE IN CONTROL OF THE LOWER LEVELS HERE. NE FLOW AND AN
EXTENSION OF THE SFC RIDGE IN PLACE WILL LIMIT PCPN POTENTIAL.
THE PERIOD FROM TUE THROUGH THU THEN WILL FEATURE THE COLDEST TEMPS
OF THE LONG TERM. THE MON SHORT WAVE WILL COMPLETE THE TRANSITION OF
THE UPPER AIR PATTERN TO MORE OF A NW FLOW ALOFT OVER THE AREA.
COLDER AIR WILL CONTINUE TO FILTER IN ON THE NRLY AND EVENTUALLY NW
LOW LEVEL FLOW. THE AIR WILL BE PLENTY COLD ENOUGH FOR LAKE
EFFECT...HOWEVER WE WILL REMAIN ON THE SOUTH SIDE OF THE NRN BRANCH
OF THE JET. SHORT WAVES DIVING SE ARE EXPECTED TO REMAIN JUST NORTH
OF THE CWFA. THIS WILL LIMIT MOISTURE DEPTH SIGNIFICANTLY AND ALSO
THE DEEP LAYER INSTABILITY.
LAKE EFFECT COULD BE MORE ROBUST IF THE UPPER JET AND THE ASSOCIATED
SHORT WAVES ARE ABLE TO DIVE JUST A LITTLE FURTHER SOUTH. WE BELIEVE
THAT THE STRONG CUTOFF UPPER LOW ACROSS THE SW U.S. AND THE RIDGE
AHEAD OF IT WILL HOLD THE NRN BRANCH OF THE JET JUST NORTH OF THE
AREA.
WE COULD SEE THE INITIAL EFFECTS OF THE CUTOFF UPPER LOW START TO
MOVE IN AS EARLY AS NEXT FRI AS WARM AND MOISTURE ADVECTION AHEAD OF
IT STARTS TO OVERRUN THE COLDER AIR EXPECTED TO BE IN PLACE. THE
MODELS TYPICALLY EJECT THESE SYSTEMS OUT TOO QUICK...SO WE WILL KEEP
THE CHC OF PCPN LOW AT THIS TIME FOR NEXT FRI.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1157 PM EST FRI DEC 26 2014
CEILING WILL SLOWLY LOWER TO IFR BY MORNING AND PERIOD OF LIGHT
RAIN OR DRIZZLE WILL ALSO DEVELOP BY THEN ALSO LOWERING
VISIBILITIES TO IFR. THE FRONT WILL COME THROUGH DURING THE
AFTERNOON AND WILL END THE PRECIPITATION AND IMPROVE VISIBILITIES.
CEILINGS WILL ONLY SLOWLY LIFT DURING THE EVENING.
&&
.MARINE...
ISSUED AT 330 PM EST FRI DEC 26 2014
THE PRESSURE GRADIENT RELAXES TONIGHT SO WINDS AND WAVES ARE
EXPECTED TO SUBSIDE. HOWEVER THEY WILL RAMP UP AGAIN LATE SATURDAY
AND SATURDAY NIGHT AS A COLD FRONT PASSES ACROSS LK MI.
&&
.HYDROLOGY...
ISSUED AT 330 PM EST FRI DEC 26 2014
HAVE CANCELED THE ADVISORY FOR THE MAPLE RIVER AT MAPLE RAPIDS AS
LATEST FORECAST HAS IT CRESTING A HALF FOOT BELOW BANKFULL SUNDAY.
SYCAMORE CREEK AT HOLT CRESTED LAST NIGHT AND IS FALLING BELOW
BANKFULL AT THIS TIME. ABOUT A TENTH OF AN INCH OF PRECIPITATION IS
EXPECTED ON SATURDAY WHICH WILL NOT AFFECT THE RIVERS MUCH. A LACK
OF SIGNIFICANT PRECIPITATION INTO THE NEW YEAR WILL ALLOW THE LARGER
RIVERS TIME TO CREST AND FALL WITHOUT MUCH IMPACT.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS...MEADE
SHORT TERM...MEADE
LONG TERM...NJJ
AVIATION...WDM
HYDROLOGY...CAS
MARINE...MEADE
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
328 AM CST SAT DEC 27 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 329 AM CST SAT DEC 27 2014
AFTER TAKING MOST OF DECEMBER OFF...THE SHORT TERM PERIOD MARKS THE
BEGINNING OF THE RETURN OF WEATHER THAT IS MORE TYPICAL OF WHAT WE
WOULD EXPECT IN THE HEART OF WINTER...AT LEAST FOR TEMPERATURES.
FEATURE DRIVING SNOW ACROSS THE AREA THIS MORNING SHOWS UP WELL ON
SATELLITE WITH A NICE SWIRL MOVING INTO THE SIOUX FALLS AREA...WITH
A NICE DRY SLOT NOSING INTO SE MN. THIS DRY SLOT IS ASSOCIATED WITH
A TROWAL...WHICH HAS HELPED FORCE A NICE DEFORMATION BAND OF PRECIP
TO THE NW OF IT. MODELS GOING BACK TO THE 00Z RUNS LAST NIGHT HAVE
ACTUALLY DONE A GOOD JOB HANDLING THIS SNOW AND PRETTY MUCH FOLLOWED
THE HOPWRF AND HRRR FOR ENDING SNOW ACROSS THE AREA THIS MORNING.
EVERYTHING APPEARS ON TRACK FOR A HEALTHY SWATH OF 3 TO 5 INCHES.
BACK TO THE WEST OF THIS LOW...THERE IS A RIDGE AXIS EXTENDING FROM
ERN COLORADO UP INTO THE ERN DAKOTAS. TEMPS AND DEWPS FALL OFF TO
WITHIN 10 DEGS OF EITHER SIDE OF ZERO WITHIN THE RIDGE AXIS...THOUGH
THIS RIDGE AXIS ALSO HAS WHAT HAS BEEN A RARITY THIS MONTH...MOSTLY
CLEAR SKIES. ITS LOOKING LIKE GOOD BET FOR SEEING SOME SUN TODAY
WEST OF I-35. EAST OF I-35...THE CLEARING WILL BE RACING
SUNSET...THOUGH BY THE TIME YOU GET TO EAU CLAIRE...IT`S A PRETTY
GOOD BET THAT SKIES WILL REMAIN OVERCAST THROUGH THE DURATION OF
DAYLIGHT HOURS. THESE MAINLY CLEAR SKIES MAY CAUSE TEMPERATURES TO
BE A BIT COOLER THAN WHAT IS CURRENTLY FORECAST TONIGHT...ESPECIALLY
WHERE WE ARE SEEING SNOW RIGHT NOW FROM SOUTHERN MN INTO WRN WI. OF
COURSE OUR TIME WITH CLEARISH SKIES WILL BE SHORT LIVED...AS BY 12Z
SUNDAY...THE ARCTIC BOUNDARY WILL BE SLIPPING INTO CENTRAL MN...WITH
CLOUD COVER INCREASING AHEAD OF THE FRONT AS IT DROPS SOUTH ACROSS
NRN MN THROUGH THE NIGHT.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 329 AM CST SAT DEC 27 2014
THE MAIN HIGHLIGHT OF THE LONG TERM FORECAST PERIOD WILL BE THE
RETURN TO BELOW NORMAL TEMPERATURES BEFORE WE RING IN THE NEW
YEAR. OTHER THAN A SLIM CHANCE FOR SNOWFALL ON SUNDAY NIGHT INTO
MONDAY AS THE ARCTIC BOUNDARY RESPONSIBLE FOR THE AFOREMENTIONED
COOL DOWN IN TEMPERATURES MOVES THROUGH...DRY WEATHER IS EXPECTED
UNTIL POSSIBLY NEXT FRIDAY.
SUNDAY WILL LIKELY BE THE ONE AND ONLY MILD DAY THROUGH MOST OF
THE UPCOMING WEEK IN ADVANCE OF THE COLD FRONT. MODEL AGREEMENT WITH
THIS FEATURE HAS NOT REALLY SHOWN MUCH IMPROVEMENT OVER THE LAST
24 HOURS. THE ECMWF HAS BEEN FAIRLY INSISTENT THAT THE FORECAST
AREA WILL MISS OUT ON SNOWFALL WITH THIS FEATURE...WHILE THE
SREF...NAM...AND NOW 27.00 GFS THINK SOUTHERN MN WILL SEE A 1-3
INCH SNOWFALL ON SUNDAY NIGHT AND MONDAY MORNING. SINCE THE ECMWF
IS A BIT OF AN OUTLIER FROM THE OVERALL MODEL CONSENSUS SOLUTION...WHICH
HAS SHOWN UP FOR MULTIPLE RUNS...HAVE INCLUDED 30 POPS FOR 00Z-18Z
MONDAY GENERALLY SOUTH OF INTERSTATE 94. HAVE HOWEVER KEPT SNOWFALL
ACCUMULATIONS AROUND ONE INCH OR LESS WITH THE THOUGHT THE
FORCING/MOISTURE MIGHT BE WEAKER/LOWER THAN PROGGED BY THE
CONSENSUS.
WHILE CONFIDENCE IS RATHER LOW WITH RESPECT TO SNOWFALL CHANCES AS
THIS BOUNDARY SURGES ACROSS THE AREA...WHAT IS MORE CERTAIN IS
THAT A BLAST OF COLDER AIR WILL FOLLOW IN ITS WAKE. THERE IS STILL
FINE AGREEMENT THAT H85 TEMPERATURES WILL REDUCE TO -18C TO -20C
BY TUESDAY. SUB-ZERO LOWS FOR TUESDAY AND WEDNESDAY MORNINGS ARE
FAIRLY CERTAIN...ALONG WITH HIGHS IN THE SINGLE DIGITS TO LOW
TEENS. WIND CHILLS WILL SNEAK TO AROUND -20F TO -30F ON MONDAY
NIGHT AND TUESDAY NIGHT...BUT MODERATE A TAD /-10F/ FOR NEW YEARS
EVE AS LOW TEMPERATURES RECOVER TO ABOVE ZERO VALUES.
AT THE END OF THE UPCOMING WEEK...GFS AND ECMWF MODELS FORECAST ANOTHER
WAVE TO DROP SOUTH FROM CANADA...THIS TIME THROUGH THE BASE OF A
HUDSON/JAMES BAY CYCLONE. WHILE TIMING/AMPLITUDE DETAILS ARE A BIT
UP IN THE AIR AT THIS POINT...THE PROGS DO WARRANT INCLUSION OF
20-30 POPS FOR SNOW ON FRIDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1051 PM CST FRI DEC 26 2014
-SN HAS OVERSPREAD MUCH OF THE WFO MPX COVERAGE AREA...INCLUDING
CEILINGS FROM LOWER-END MVFR INTO BARELY IFR RANGE WITH VSBYS AS
LOW AS 1SM IN SOME OF THE HEAVIER SNOW BANDS. THE SNOWFALL WILL
CONTINUE TO FILL IN FROM THE SW OVERNIGHT...AFFECTING ALL BUT KAXN
AND POSSIBLY NOT KSTC...OR AT LEAST NOT AS BAD AT KSTC AS THE
REMAINING TAF SITES. ALL SITES /BUT KAXN/ WILL EXPERIENCE FLIGHT
CATEGORY REDUCTIONS AT TIMES TO IFR DURING THE FIRST HALF OF THIS
TAF PERIOD. HAVE DROPPED CONDS TO AS LOW AS 1SM...BUT GOING LESS
THAN THAT FOR VSBY CERTAINLY CANNOT BE RULED OUT. SAME WITH
CEILINGS...SEEING IFR CONDS WILL BE LIKELY WITH CEILINGS INTO LIFR
NOT UNREASONABLE. CONDS WILL IMPROVE FROM DAYBREAK ON THRU LATE
MRNG AS THE -SN PULLS OUT. VFR CONDS ARE EXPECTED BY LATE SAT
AFTN INTO EARLY SAT EVE.
KMSP...CONDS HAVE IMPROVED AT KMSP...EVEN TO VFR AT TIMES...AFTER
THE INITIAL BAND OF SNOW DEVELOPED OVER THE S/E TWIN CITIES
METRO AT THE START OF THE 27/00Z TAF. MORE WIDESPREAD SNOW IS
EXPECTED DURING THE THE EARLY MRNG HRS. CONDS IMPROVE AROUND
DAYBREAK. VSBY MAY WELL DROP BELOW 1SM FOR A TIME...BUT RATES OF 1
IN/HR ARE NOT EXPECTED BUT WILL CONTINUE TO MONITOR FOR ANY
POTENTIAL OF AN AIRPORT WEATHER WARNING AS THE EVENT UNFOLDS.
AFTER DAYBREAK...CEILINGS WILL INCRS TO MVFR LEVELS AND LIKELY GO
TO VFR SAT AFTN-EVE.
/OUTLOOK FOR KMSP/
SUN...VFR...CHC MVFR CIGS. WINDS S 5 KTS...BCMG E.
MON...VFR. WINDS N 10 KTS.
TUE...VFR. WINDS NW 5-10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER WEATHER ADVISORY UNTIL 9 AM CST THIS MORNING FOR MNZ053-
060>063-065>070-073>078-082>085-091>093.
WI...WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR WIZ014>016-
023>028.
&&
$$
SHORT TERM...MPG
LONG TERM...LS
AVIATION...JPC
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1151 PM CST Fri Dec 26 2014
.UPDATE...
Issued at 958 PM CST FRI DEC 26 2014
Adjusted overnight PoPs for radar trends and added drizzle (did that
awhile back). Have also pulled Pops westward into the southwestern
CWA Saturday morning to account for latest HRRR trend towards
developing a secondary area of light precipitation northeastward into
east central KS/west central MO. Satellite imagery shows rapid
increase in upstream mid clouds from southeast NM through western OK.
Some question as to whether or not the 00z NAM`s dry wedge under this
cloud layer is real or not. 00z OKC sounding suggests otherwise. 12z
ECMWF supports the HRRR solution while the 00z GFS does pick up on
some QPF Sat morning making it into our southeastern CWA.
Precipitation type dependent on near surface temperatures and
vertical stratification of same. Tricky. Fortunately QPF should be
minor.
&&
.DISCUSSION...
Issued at 307 PM CST FRI DEC 26 2014
Cold front has reached the KC area this afternoon, though its
southward progress has slowed with a weak surface wave moving
up from the south. This feature is starting to produce some light
showers across west central Missouri, and light precip should
continue to blossom through the late afternoon and evening as low
pressure rides up the boundary. Precip amounts will be light,
generally less than a tenth of an inch, and mostly confined to areas
near and southeast of the I-35 corridor. Temperatures should remain
above freezing across these areas so no wintry precipitation is
expected.
Behind the front, a second area of precipitation developing over
central KS will spread into eastern Nebraska and northern Iowa
overnight where several inches of snow will accumulate, but most of
this snowfall now looks like it will miss our forecast area almost
entirely to the north. While far northwest Missouri may still see
some light snow later this evening, possibly even a bit of sleet, any
accumulations should be very minor and may not accumulate at all with
relatively warm ground temperatures.
Airmass behind the front will be seasonably chilly with highs in the
30s and lows in the teens/20s over the weekend. A stronger front will
swing through the region on Monday and looks to bring some of the
coldest air of the season so far. Highs Tuesday and Wednesday are
forecast to be in the 20s...maybe even teens for some areas...while
lows drop into the single digits. Wind chills could be between zero
and 10 below. Other than perhaps some very light snow accompanying
Monday`s front, the forecast through the middle of next week looks
dry. The pattern then looks to get active by late next week with both
GFS and ECMWF taking a closed upper low out of the Southwest and into
the Plains/Midwest by Friday/Saturday. Will be interesting to watch how
future model runs play out, but given the inherent low-predictability
with such a system, several swings in track and intensity are highly
likely and we are still days away from knowing any details, or even
if such a system will impact our region at all.
&&
.AVIATION...(For the 06Z TAFS through 06Z Saturday Night)
Issued at 1140 PM CST FRI DEC 26 2014
Ceilings have finally begun to lower towards low MVFR and upper IFR
range as light rain across eastern KS moves northeastward towards
KSTJ and KMCI. KMKC looks to stay on the edge of the heavier band
with just a quick light shower in the near term. Question is if
disjointed band of rain showers currently across northeast OK will be
able to hold up and move up into eastern KS over the next several
hours. Lower ceilings and a reduction of VISIBILITIES are expected
to move in behind this current rain band given upstream obs. IFR deck
will begin to scatter out by mid morning with MVFR deck looking to
scatter out by 20-21Z. Skies will clear as the upper level system
moves east and surface high pressure moves into the region.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
UPDATE...MJ
DISCUSSION...Hawblitzel
AVIATION...PMM
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1127 PM CST FRI DEC 26 2014
.UPDATE...
ISSUED AT 1119 PM CST FRI DEC 26 2014
WILL BE UPDATING BY THE TOP OF THE HOUR FOR EXPIRATION OF MUCH OF
THE WINTER WEATHER ADVISORY. ONE MORE SIGNIFICANT BAND ALONG
HIGHWAY 30 NEAR GRAND ISLAND WILL EXIT NANCE AND MERRICK COUNTIES
AROUND 1230 AM. MUCH OF THE REST OF THE AREA WILL STILL HAVE SOME
RESTRICTED VISIBILITIES AND LIGHT SNOW FOR A FEW MORE HOURS...BUT
INTENSITY IS REALLY STARTING TO DROP OFF...WHICH WAS THE EXPECTED
TREND. WINDS ALSO REMAIN BELOW 15 MPH WHICH IS HELPFUL FOR LESS
BLOWING SNOW. TREND OF CLEARING ALREADY TAKING HOLD IN THE
SOUTHWEST PORTION OF THE FORECAST AREA...AND THAT WILL SPREAD
NORTHEAST THROUGH THE NIGHT.
UPDATE ISSUED AT 914 PM CST FRI DEC 26 2014
SENT AN UPDATE TO THE FORECAST TO REFINE THE TIMING OF PRECIP
THROUGH THE OVERNIGHT HOURS...LINGERING SOME LIGHT ACCUMULATING
SNOWFALL ACROSS OUR NORTHERN COUNTIES THROUGH THE EARLY MORNING
HOURS SATURDAY WHERE THE ADVISORY WAS RECENTLY EXTENDED. LATEST
SATELLITE IMAGERY SHOWS THE UPPER LEVEL LOW ACROSS WESTERN
NEBRASKA BEGINNING TO PIVOT AND LIFT NORTHEASTWARD...WHICH SHOULD
RESULT IN SNOWFALL TAPERING OFF FROM SOUTH TO NORTH OVERNIGHT.
FOLLOWED 02Z RAP GUIDANCE FAIRLY CLOSELY WITH TIMING OF PRECIP AND
TEMPERATURES OVERNIGHT...WITH NO CHANGES MADE TO THE PREVIOUS
FORECAST BEYOND THE OVERNIGHT HOURS.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 324 PM CST FRI DEC 26 2014
WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL MIDNIGHT TONIGHT.
AT 21Z...SNOWFALL WAS ONGOING ACROSS PARTS OF OUR WESTERN AND
SOUTHWESTERN COUNTIES. SNOWFALL WILL CONTINUE TO OVERSPREAD AREAS
EAST THROUGHOUT THE REST OF THE AFTERNOON AND INTO THE EVENING
HOURS. ACROSS THE ADVISORY AREA...2 TO 4 INCHES IS EXPECTED...AND
GENERALLY 1 TO 3 ACROSS THE REST OF THE OUTLOOK AREA. FOR THE HEART
OF THE CWA...WHICH IS BASICALLY THE TRI-CITIES...WE ARE CONFIDENT
THE HEAVIEST SNOWFALL WILL LIKELY FALL BETWEEN 6PM AND 9 PM TONIGHT.
SNOWFALL WILL CONTINUE UNTIL ABOUT 11PM/MIDNIGHT BEFORE TAPERING
OFF. FOR 00Z...FORECAST SOUNDINGS FOR GRAND ISLAND SHOWED THE
STRONGEST OMEGA VALUES WHICH COINCIDED WITH A MOIST DGZ
LAYER...HENCE THE CONFIDENCE FOR HEAVIEST SNOWFALL DURING THIS TIME.
ALSO HELPING CREATE A FAVORABLE TIME FRAME FOR HEAVIEST SNOW AROUND
00Z IS AN AREA OF ISENTROPIC LIFT CENTERED THROUGH MOST OF THE
CWA...ALBEIT THIS TIME FRAME IS LIMITED TO ABOUT 3 HOURS.
THEREAFTER...WE QUICKLY BEGIN TO LOSE FORCING AND MOISTURE...SO
CONFIDENT SNOW WILL RETREAT FROM THE SOUTHWEST TO NORTHEAST BETWEEN
MIDNIGHT AND SUNRISE SATURDAY MORNING.
CLOUD COVER WILL SLOWLY DECREASE LATE SATURDAY MORNING/EARLY
AFTERNOON...AND WE SHOULD SEE SOME SUNNY SKIES MID TO LATE SATURDAY
AFTERNOON. HIGHS WILL BE ON THE COOL SIDE...WITH MID/UPPER 20S TO
LOWER 30S CURRENTLY FORECAST. LOWS TONIGHT WILL GENERALLY RANGE
BETWEEN THE TEENS AND LOWER 20S.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 324 PM CST FRI DEC 26 2014
SUGGEST HAVING THE HEAVY WINTER COATS/GLOVES/HATS READY AND THOSE
WHO USE WOOD STOVES FOR HEAT KEEP PLENTY OF WOOD CLOSE BY. WE ARE IN
FOR ANOTHER PERIOD OF SERIOUS WINTER COLD...BUT THIS TIME MUCH
COLDER THAN NOV!
THE COLDEST HIGH TEMP IN GRAND ISLAND /GRI/ WAS 20F ON THE NOV 17TH.
WE WILL EXPERIENCE THE COLDEST AIR SO FAR THIS COLD SEASON. WE HAVE
TWO DAYS IN THIS FCST IN WHICH HIGHS WILL BE COLDER THAN 20F.
NOT QUITE CONFIDENT YET TO STATE HOW MANY CONSECUTIVE DAYS TEMPS
COULD REMAIN AT OR BELOW FRZG. DOWNSLOPE WARMING IS ALWAYS A
WILDCARD BETWEEN ARCTIC FRONTAL PASSAGES AS THE HIGHS DROP S OF THE
REGION. SUFFICE TO SAY THERE COULD BE A 1 OR 2 DAY INTERRUPTION...
BUT OVERALL BELIEVE WE ARE LOOKING AT AN EXTENDED STRETCH OF COLD
WX BEGINNING MON.
MODELS: THE EC/GFS/UKMET/GEM AND THE ENSEMBLE MEANS CONT IN VERY
GOOD AGREEMENT ON THE OVERALL PATTERN THRU FRI 1/2 AND ALL THE
WAY OUT THRU 10 DAYS.
THE LONGWAVE FLOW WILL BE HIGHLY AMPLIFIED WITH A RIDGE OVER THE NE
PAC INTO AK WITH A DOWNSTREAM +TILT TROF FROM HUDSON BAY INTO THE
WRN USA. THIS IS THE PATTERN WE SAW IN NOV AND IT WILL DELIVER BELOW
NORMAL TEMPS NEXT WEEK...WITH A COUPLE TWO-DAY PERIODS OF MUCH BELOW
NORMAL BITTER COLD. THAT MEANS DAYTIME HIGHS IN THE SINGLE DIGITS AND
TEENS WHICH WILL BE 20-25F COLDER THAN NORMAL. AS OF NOW THE COLDEST
DAYS ARE SLATED FOR 12/30-31 WITH HIGH CONFIDENCE AND 1/3-4 WITH
LOW CONFIDENCE.
ALOFT: A BROAD TROF WITH GENERALLY W FLOW WILL BE OVER THE PLAINS
THRU TUE. A SHORTWAVE TROF IS CURRENTLY CRESTING THE RIDGE OVER THE
GULF OF AK. THIS TROF WILL DIVE INTO THE WRN USA SAT-MON AND CUT-OFF
OVER CA TUE...GRADUALLY SINKING INTO THE DESERT SW THRU FRI.
CONFLUENT NW FLOW WILL DEVELOP OVER THE CNTRL USA IN THE MEANTIME.
ANOTHER SHORTWAVE TROF DIVING THRU WRN N AMERICA LATE NEXT WEEK
SHOULD KICK THIS LOW E...RESULTING IN A SIZABLE STORM FOR THE CNTRL/
ERN USA AND ANOTHER COLD SURGE. LOOKS LIKE THE NEXT WX-MAKER WILL BE
A WEAK SHORTWAVE TROF SUN NIGHT INTO MON.
SURFACE: HIGH PRES WILL BE OVERHEAD SAT EVE AND DRIFT S AND E OF THE
REGION OVERNIGHT WHILE THE LEADING EDGE OF THE ARCTIC AIR SPILLS
INTO THE NRN USA. THE FRONT WILL MOVE THRU SUN NIGHT WITH BITTERLY
COLD ARCTIC HIGH PRES OVER WRN CANADA SLOWLY SLIDING DOWN THE FRONT
RANGE. THIS HIGH WILL BE OF THE 1050+ MB VARIETY AND WILL BE
OVERHEAD DAYBREAK WED. IT THEN HEADS INTO THE SRN USA THU-FRI. AN
ALBERTA CLIPPER WILL DIVE SE INTO THE NRN PLAINS HERALDING THE NEXT
SURGE OF ARCTIC AIR WITH ITS ARRIVAL PROBABLY NEXT WEEKEND. SRN
PLAINS CYCLOGENESIS APPEARS IN THE OFFING LATE NEXT WEEK. THIS WILL
BEEN TO BE WATCHED.
THE DAILY DETAILS...
PLEASE GIVE US SOME LATITUDE ON TEMPS. FRESH SNOWCOVER IS ALWAYS A
SIGNIFICANT COMPLICATION ON TEMP FORECASTING.
SUN: A SUNNY START...BUT INCREASING MULTI-LAYERED MID-HIGH CLOUDS.
SUN NIGHT: ARCTIC COLD FRONTAL PASSAGE.
MON: CLOUDY/BLUSTERY AND COLD. STEADY OR SLOWLY FALLING TEMPS IN
COLD AIR ADVECTION. FOR MOST LOCATIONS DAYTIME HIGHS WILL OCCUR AT
DAWN. N WINDS WILL GUST TO 30 MPH AT TIMES. COULD SEE A BURST OF
LIGHT SNOW WITH THE WEAK SHORTWAVE TROF AND DEEP MOISTURE.
CANT RULE OUT A WIND-BLOWN INCH OR SO BUT IT/S WAY TOO EARLY AND THE
POTENCY ALOFT IS LACKING. FOR WHAT IT/S WORTH THE 06Z/12Z GFS
INDICATE THIS POTENTIAL...BUT THE SREF PROBABILITIES FOR .10" QPF
ARE CURRENTLY HIGHEST ALONG THE NEB-SD BORDER.
TUE: BITTERLY COLD. HIGHS ONLY IN THE SINGLE DIGITS FOR MUCH OF S-
CNTRL NEB. MID TEENS FOR N-CNTRL KS. WATCH YOUR HOME BAROMETERS. IF
IT/S ARE CALIBRATED...YOU WILL LIKELY SEE PRESSURE EXCEEDING 30.80".
WED: COULD BE A VERY VERY COLD START AS LONG AS CLOUDS ARE NOT A
FACTOR. COLDEST LOCATIONS WOULD BE THE USUAL COLD SPOTS N AND W OF
THE TRI-CITIES...ESPECIALLY THE LOUP RVR VALLEY. HIGH PRES OVERHEAD
TUE NIGHT WOULD RESULT IN VERY LIGHT WINDS.
THU-FRI: MODERATING TEMPS. DRY THU AND PROBABLY FRI. BUT FRI NEEDS
TO BE WATCHED AS LOW PRES WILL BE ORGANIZING S OF THE REGION. GFS
ENSEMBLES SUGGEST THIS LOW WILL MISS WELL SE OF THE FCST AREA... BUT
A LOT CAN CHANGE BETWEEN NOW AND THEN.
&&
.AVIATION...(FOR THE 06Z KGRI/KEAR TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1119 PM CST FRI DEC 26 2014
MVFR CONDITIONS WILL LINGER FOR A COUPLE MORE HOURS AS THE SNOW
BAND STARTS TO MOVE NORTHEAST OF THE AREA. SEEING TRENDS TOWARD
CLEARING ALREADY MOVING INTO THE SOUTH CENTRAL NEBRASKA...SO
FAIRLY QUICK IMPROVEMENT TO VFR CONDITIONS WILL BE FOUND BY DAWN.
WINDS WILL GRADUALLY DROP THROUGH THE DAY TO LESS THAN 10KTS. VFR
CONDITIONS ARE EXPECTED AFTER DAWN AND INTO TONIGHT.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR NEZ041-
046>048-060>062-072>074-082-083.
WINTER WEATHER ADVISORY UNTIL 4 AM CST SATURDAY FOR NEZ039-040.
KS...NONE.
&&
$$
UPDATE...NOAA/NWS/MORITZ
SHORT TERM...GUERRERO
LONG TERM...HALBLAUB
AVIATION...NOAA/NWS/MORITZ
AREA FORECAST DISCUSSION
NWS RALEIGH NC
329 AM EST SAT DEC 27 2014
.SYNOPSIS...HIGH PRESSURE OVERHEAD THIS MORNING WILL SHIFT EAST OF
THE AREA BY TONIGHT. A COLD FRONT WILL APPROACH FROM THE NORTHWEST
ON SUNDAY... AND GRADUALLY MOVE SOUTHWARD THROUGH THE REGION ON
MONDAY.
&&
.NEAR TERM /THROUGH SATURDAY/...
AS OF 840 PM FRIDAY...
ANOTHER QUIET NIGHT WITH BOTH SURFACE HIGH PRESSURE AND MID LEVEL
RIDGING OVERHEAD AND DEEP DRY AND STABLE AIR FROM THE SURFACE UP
THROUGH 500 MB. A SLUG OF HIGHER LEVEL MOISTURE TRACKING AROUND THE
PERIPHERY OF THE RIDGE... NOW MOVING OVER TN/KY/WV/VA... WILL AFFECT
FAR NRN AND NW CWA WITH A PERIOD HIGH THIN CLOUDS... HOWEVER THIS IS
UNLIKELY TO HAVE MUCH IF ANY IMPACT ON TEMPS. WINDS HAVE GONE CALM
IN MOST AREAS... FACILITATING A GOOD TEMP DROP THIS EVENING.
DEWPOINT DEPRESSIONS ARE ALREADY DOWN TO JUST A FEW DEGREES
ESPECIALLY IN THE EAST... WHERE DEWPOINTS ARE GENERALLY HIGHER THAN
IN THE WEST... AND THE LATEST HRRR DEPICTS AREAS OF FOG FORMING
AFTER 09Z ALONG THE I-95 CORRIDOR. HAVE ADDED A MENTION OF FOG IN
THE COASTAL PLAIN LATE TONIGHT INTO SAT MORNING. OTHERWISE... EXPECT
MOSTLY CLEAR SKIES. LOWS 29-36... LOWEST IN OUTLYING AREAS. -GIH
THE HIGH WILL BEGIN TO SLIP OFFSHORE ON SATURDAY AHEAD OF OUR NEXT
SYSTEM. THE AIRMASS WILL UNDERGO FURTHER MODIFICATION AS RETURN FLOW
SETS UP OVER THE REGION. HIGHS SHOULD RISE INTO THE UPPER 50S TO
NEAR 60 DEGREES ACROSS THE NORTHWEST (WHERE MID/HIGH CLOUDS WILL BE
FIRST TO ARRIVE) AND INTO THE LOW/MID 60S FURTHER SOUTHEAST. -KRD
&&
.SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/...
AS OF 305 PM FRIDAY...
SATURDAY NIGHT...SW FLOW ALOFT WILL USHER IN A SERIES OF
DISTURBANCES FROM THE NORTHERN GULF INTO THE SOUTHERN
APPALACHIANS/MID-ATLANTIC REGION. LEAD DISTURBANCE PROJECTED TO
ADVANCE TOWARD OUR REGION LATE SATURDAY NIGHT. MID LEVEL FLOW WILL
GRADUALLY VEER IN RESPONSE TO THIS FEATURE...AIDING IN MOISTURE
TRANSPORT INTO THE REGION. SFC RIDGE IS EXPECTED TO REMAIN ALIGNED
WSW-ENE ACROSS CENTRAL NC...MAINTAINING A DRY AIR PRESENCE. LOW
LEVEL ISENTROPIC LIFT ANEMIC DURING THIS PERIOD SO APPEARS LIFT
GENERATED ALOFT FROM WAA. EXPECT DRY CONDITIONS THROUGH SATURDAY
EVENING WITH PATCHES OF LIGHT RAIN SHOWING UP ON THE RADAR AFTER
MIDNIGHT IN THE WEST. INITIAL PATCHES OF RAIN WILL GO TO MOISTEN THE
SUB CLOUD LAYER. THUS...BEST SHOT OF MEASURABLE RAIN WILL LIKELY BE
CONFINED TO THE FAR WESTERN-SOUTHERN PIEDMONT.
SUNDAY...ATMOSPHERE EXPECTED TO REMAIN ADEQUATELY MOIST TO MAINTAIN
CONSIDERABLE CLOUDINESS. LEAD PERTURBATION EXPECTED TO CROSS JUST
WEST-NW OF OUR REGION IN THE MORNING. BULK OF PRECIP WITH THIS
FEATURE SHOULD OCCUR IN VICINITY OF THE PIEDMONT COUNTIES WITH RAIN
COVERAGE DECREASING TO THE SE. WILL TREND POPS FROM LIKELY NW THIRD
TO CHANCE FAR SE. BY AFTERNOON...EXPECT NOTHING MORE THAN SPOTTY
PRECIP AT THIS TIME WITH CHANCE POPS AREAWIDE. MAX TEMPS SUNDAY
DEPENDENT ON AREAL EXTENT OF RAIN OR SHOWERS. FAVOR BLEND OF MOS
GUIDANCE (UPPER 50S NW TO LOW-MID 60S SE). MORE EXTENSIVE/LONGER
DURATION RAIN WILL RESULT IN COOLER TEMPS BY 3-4 DEGREES.
SUNDAY NIGHT...MODEL GUIDANCE HAS GAINED SOME CONSENSUS ON A
SLIGHTLY MORE PRONOUNCED PERTURBATION AND ATTENDANT SURFACE WAVE TO
AFFECT OUR REGION SUNDAY NIGHT...ESPECIALLY AFTER MIDNIGHT. MAIN
LIFTING MECHANISM APPEARS TO BE FROM A 140+ UPPER JET LIFTING NWD
ACROSS THE NORTHERN MID ATLANTIC...PLACING CENTRAL NC IN THE
FAVORABLE RIGHT ENTRANCE REGION. THIS MAY LEAD TO RAINFALL AMOUNTS
ON THE ORDER OF A HALF INCH OVER THE PIEDMONT. PLAN TO TREND POPS
FROM CHANCE IN THE EVENING TO HIGH LIKELY LATE SUNDAY NIGHT INTO THE
FIRST PART OF MONDAY MORNING. LOWS IN THE MID 40S NW TO LOWER 50S SE.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 325 AM SATURDAY...
MON AND MON NIGHT: THE MODELS ARE IN GOOD AGREEMENT ALOFT REGARDING
THE AMPLIFICATION OF A SHORTWAVE TROUGH ACROSS NORTHERN MEXICO
THROUGH TONIGHT... FOLLOWED BY A DEAMPLIFICATION OF THE TROUGH TO
THE MIDDLE ATLANTIC STATES BY EARLY MON. THE INTENSIFICATION AND
MIGRATION OF AN ASSOCIATED 160-180 KT UPPER JET ACROSS THE OH VALLEY
AND NORTHEAST WILL PLACE CENTRAL NC BENEATH THE RIGHT ENTRANCE
REGION OF THE JET...WHICH WILL CAUSE THE LOW LEVEL FLOW /ABOVE THE
SHALLOW POST-FRONTAL DAMMING HIGH/ TO ACCELERATE AND ASSUME A MORE
SOUTHERLY COMPONENT. STRENGTHENING ISENTROPIC LIFT WILL
RESULT...WHICH WILL CAUSE LIGHT RAIN TO OVERSPREAD CENTRAL NC LATE
SUNDAY NIGHT THROUGH EARLY MON AFTERNOON...BEFORE TAPERING TO
OCCASIONAL DRIZZLE OR BARELY MEASURABLE LIGHT RAIN...AS AN
ASSOCIATED SERIES OF WEAK FRONTAL WAVES TRACK OFF THE COAST OF THE
CAROLINAS...THROUGH MON NIGHT.
THE COMBINATION OF BOTH CAA AND DIABATIC/EVAPORATIVE COOLING WILL
LIKELY RESULT IN SLOWLY FALLING TEMPERATURES ACROSS THE NORTHERN
CWFA --INTO THE 40S-- THROUGHOUT THE DAY...WHILE THE SOUTHERN TIER
WILL HAVE AN OPPORTUNITY TO WARM INTO THE 60S DURING THE MIDDAY
HOURS BEFORE ALSO COOLING DURING THE AFTERNOON HOURS. LOWS...WITH
CONTINUED LOW OVERCAST AND THE AFOREMENTIONED OCCASIONAL DRIZZLE OR
VERY LIGHT RAIN...IN THE UPPER 30S TO LOWER 40S.
TUE: A SECONDARY SHORTWAVE TROUGH...ANOTHER DEAMPLIFYING ONE IN WSW
FLOW ALOFT...IS FORECAST TO CROSS THE CENTRAL APPALACHIANS EARLY
TUE. THE PASSAGE OF THIS FEATURE AND ASSOCIATED WEAK HEIGHT FALLS
ALOFT AND LIFT WILL MAINTAIN A SUFFICIENTLY SATURATED LOWEST SEVERAL
THOUSAND FT TO WARRANT A CONTINUED SLIGHT CHANCE OF LIGHT RAIN OR
(MORE LIKELY) DRIZZLE INTO EARLY TUE...BEFORE NW 925-850 MB FLOW
BEHIND THE PASSING SHORTWAVE PROMOTES BOTH DOWNSLOPE FLOW AND A
DISSIPATION OF THE CAD INVERSION VIA CAA - BOTH MECHANISMS THAT
SHOULD SERVE TO SCOUR THE CAD REGIME AND PROMOTE STEADY CLEARING.
WITH A FEW HOURS OF AFTERNOON SUNSHINE PROBABLE...LONGEST OVER THE
NW PIEDMONT...TEMPERATURES SHOULD RESPOND TO NEAR NORMAL.
TUE NIGHT-FRI: STRONG...ARCTIC HIGH PRESSURE OVER THE ROCKIES EARLY
IN THE PERIOD WILL OTHERWISE SPRAWL EAST ACROSS THE MIDDLE ATLANTIC
AND SOUTHEAST STATES...THROUGH THU...BENEATH GENERALLY WESTERLY FLOW
BETWEEN CONFLUENT BRANCHES OF THE UPPER JET...BEFORE DRIFTING
OFFSHORE AHEAD OF AN EJECTING DESERT SW (BRIEFLY) CUTOFF LOW FRI-
SAT. THE RESULT WILL BE COOL CONDITIONS --MOST NOTABLY WED AND THU
MORNINGS WHEN TEMPERATURES SHOULD DIP WELL INTO THE 20S GIVEN
PROJECTED LOW LEVEL THICKNESS VALUES IN THE 1290-1300 METER RANGE--
WITH A PERIOD OF PASSING MID-HIGH CLOUDS DURING THE DAY
WED...BETWEEN OTHERWISE MOSTLY CLEAR.
MEDIUM RANGE GUIDANCE (NOT SURPRISINGLY) DIVERGES WITH RESPECT TO
THE EJECTION OF THE AFOREMENTIONED DESERT SW LOW...SO FORECAST
DETAILS ARE MORE UNCERTAIN FOR FRI...THOUGH CLOUDINESS AND RAIN
CHANCES WILL CERTAINLY BE ON THE RISE THROUGH THE START OF NEXT
WEEKEND.
&&
.AVIATION /06Z SATURDAY THROUGH TUESDAY/...
AS OF 100 AM SATURDAY...
WITH DEWPOINTS SLIGHTLY HIGHER OVER THE COASTAL PLAIN AND LIGHT
WINDS...THERE MAY BE A COUPLE HOURS OF MVFR VSBY AT KRWI AND/OR KFAY
PRIOR TO 12Z...ESPECIALLY AS SKIES PARTIALLY CLEAR BETWEEN SOME HIGH
CLOUDS MOVING OVERHEAD. OTHERWISE.. VFR CONDITIONS ARE EXPECTED TO
CONTINUE THROUGH THE TAF PERIOD WITH LIGHT WINDS BECOMING SOUTH-
SOUTHWESTERLY DURING THE DAY.
MID-LEVEL CLOUDS WILL INCREASE LATER TONIGHT AND EARLY SUNDAY AHEAD
OF A DISTURBANCE MOVING ALONG THE APPALACHIANS. HOWEVER...CURRENT
MODEL PROJECTIONS HAVE LOW CLOUDS AND SUB-VFR CEILINGS SPREADING
INTO THE KGSO/KINT VICINITY WELL AFTER 06Z SUNDAY.
LOOKING AHEAD: A SERIES OF UPPER-LEVEL DISTURBANCES MOVING SOUTHWEST
TO NORTHEAST ACROSS THE REGION COMBINED WITH AN APPROACHING FRONTAL
ZONE WILL BRING A COUPLE ROUNDS OF LIGHT PRECIP AND SUB-VFR
CONDITIONS TO PORTIONS OF CENTRAL NC SUNDAY AND MONDAY. CONDITIONS
ARE EXPECTED TO IMPROVE BY LATE MONDAY NIGHT INTO TUESDAY. -KRD
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BLS
NEAR TERM...HARTFIELD/KRD
SHORT TERM...WSS
LONG TERM...MWS
AVIATION...BLS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
100 AM EST SAT DEC 27 2014
.SYNOPSIS...HIGH PRESSURE OVERHEAD THIS MORNING WILL SHIFT EAST OF
THE AREA BY TONIGHT. A COLD FRONT WILL APPROACH FROM THE NORTHWEST
ON SUNDAY... AND GRADUALLY MOVE SOUTHWARD THROUGH THE REGION ON
MONDAY.
&&
.NEAR TERM /THROUGH SATURDAY/...
AS OF 840 PM FRIDAY...
ANOTHER QUIET NIGHT WITH BOTH SURFACE HIGH PRESSURE AND MID LEVEL
RIDGING OVERHEAD AND DEEP DRY AND STABLE AIR FROM THE SURFACE UP
THROUGH 500 MB. A SLUG OF HIGHER LEVEL MOISTURE TRACKING AROUND THE
PERIPHERY OF THE RIDGE... NOW MOVING OVER TN/KY/WV/VA... WILL AFFECT
FAR NRN AND NW CWA WITH A PERIOD HIGH THIN CLOUDS... HOWEVER THIS IS
UNLIKELY TO HAVE MUCH IF ANY IMPACT ON TEMPS. WINDS HAVE GONE CALM
IN MOST AREAS... FACILITATING A GOOD TEMP DROP THIS EVENING.
DEWPOINT DEPRESSIONS ARE ALREADY DOWN TO JUST A FEW DEGREES
ESPECIALLY IN THE EAST... WHERE DEWPOINTS ARE GENERALLY HIGHER THAN
IN THE WEST... AND THE LATEST HRRR DEPICTS AREAS OF FOG FORMING
AFTER 09Z ALONG THE I-95 CORRIDOR. HAVE ADDED A MENTION OF FOG IN
THE COASTAL PLAIN LATE TONIGHT INTO SAT MORNING. OTHERWISE... EXPECT
MOSTLY CLEAR SKIES. LOWS 29-36... LOWEST IN OUTLYING AREAS. -GIH
THE HIGH WILL BEGIN TO SLIP OFFSHORE ON SATURDAY AHEAD OF OUR NEXT
SYSTEM. THE AIRMASS WILL UNDERGO FURTHER MODIFICATION AS RETURN FLOW
SETS UP OVER THE REGION. HIGHS SHOULD RISE INTO THE UPPER 50S TO
NEAR 60 DEGREES ACROSS THE NORTHWEST (WHERE MID/HIGH CLOUDS WILL BE
FIRST TO ARRIVE) AND INTO THE LOW/MID 60S FURTHER SOUTHEAST. -KRD
&&
.SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/...
AS OF 305 PM FRIDAY...
SATURDAY NIGHT...SW FLOW ALOFT WILL USHER IN A SERIES OF
DISTURBANCES FROM THE NORTHERN GULF INTO THE SOUTHERN
APPALACHIANS/MID-ATLANTIC REGION. LEAD DISTURBANCE PROJECTED TO
ADVANCE TOWARD OUR REGION LATE SATURDAY NIGHT. MID LEVEL FLOW WILL
GRADUALLY VEER IN RESPONSE TO THIS FEATURE...AIDING IN MOISTURE
TRANSPORT INTO THE REGION. SFC RIDGE IS EXPECTED TO REMAIN ALIGNED
WSW-ENE ACROSS CENTRAL NC...MAINTAINING A DRY AIR PRESENCE. LOW
LEVEL ISENTROPIC LIFT ANEMIC DURING THIS PERIOD SO APPEARS LIFT
GENERATED ALOFT FROM WAA. EXPECT DRY CONDITIONS THROUGH SATURDAY
EVENING WITH PATCHES OF LIGHT RAIN SHOWING UP ON THE RADAR AFTER
MIDNIGHT IN THE WEST. INITIAL PATCHES OF RAIN WILL GO TO MOISTEN THE
SUB CLOUD LAYER. THUS...BEST SHOT OF MEASURABLE RAIN WILL LIKELY BE
CONFINED TO THE FAR WESTERN-SOUTHERN PIEDMONT.
SUNDAY...ATMOSPHERE EXPECTED TO REMAIN ADEQUATELY MOIST TO MAINTAIN
CONSIDERABLE CLOUDINESS. LEAD PERTURBATION EXPECTED TO CROSS JUST
WEST-NW OF OUR REGION IN THE MORNING. BULK OF PRECIP WITH THIS
FEATURE SHOULD OCCUR IN VICINITY OF THE PIEDMONT COUNTIES WITH RAIN
COVERAGE DECREASING TO THE SE. WILL TREND POPS FROM LIKELY NW THIRD
TO CHANCE FAR SE. BY AFTERNOON...EXPECT NOTHING MORE THAN SPOTTY
PRECIP AT THIS TIME WITH CHANCE POPS AREAWIDE. MAX TEMPS SUNDAY
DEPENDENT ON AREAL EXTENT OF RAIN OR SHOWERS. FAVOR BLEND OF MOS
GUIDANCE (UPPER 50S NW TO LOW-MID 60S SE). MORE EXTENSIVE/LONGER
DURATION RAIN WILL RESULT IN COOLER TEMPS BY 3-4 DEGREES.
SUNDAY NIGHT...MODEL GUIDANCE HAS GAINED SOME CONSENSUS ON A
SLIGHTLY MORE PRONOUNCED PERTURBATION AND ATTENDANT SURFACE WAVE TO
AFFECT OUR REGION SUNDAY NIGHT...ESPECIALLY AFTER MIDNIGHT. MAIN
LIFTING MECHANISM APPEARS TO BE FROM A 140+ UPPER JET LIFTING NWD
ACROSS THE NORTHERN MID ATLANTIC...PLACING CENTRAL NC IN THE
FAVORABLE RIGHT ENTRANCE REGION. THIS MAY LEAD TO RAINFALL AMOUNTS
ON THE ORDER OF A HALF INCH OVER THE PIEDMONT. PLAN TO TREND POPS
FROM CHANCE IN THE EVENING TO HIGH LIKELY LATE SUNDAY NIGHT INTO THE
FIRST PART OF MONDAY MORNING. LOWS IN THE MID 40S NW TO LOWER 50S SE.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 325 PM FRIDAY...
MONDAY THROUGH FRIDAY... PERTURBATION ALOFT AND ASSOCIATED SURFACE
WAVE AND FRONT WILL CROSS CENTRAL NC MONDAY MORNING. W-NW FLOW
BEHIND THE EXITING WEATHER SYSTEM MONDAY AFTERNOON-NIGHT WILL LEAD
TO DRIER AND MORE STABLE CONDITIONS. BASED ON CURRENT MODEL
TIMING...FAVOR HIGHEST POPS MONDAY MORNING WITH DECREASING POPS
MONDAY AFTERNOON AND LESS THAN 20 PERCENT POPS BY MONDAY NIGHT.
TEMPS MONDAY DEPENDENT UPON EVENTUAL TRACK OF THE SURFACE LOW. SOME
MODELS FAVOR A TRACK CLOSER TO THE NW PIEDMONT...PLACING BULK OF CWA
IN THE WARM SECTOR. OTHER MODELS CLUSTER AROUND A SOLUTION WITH THE
SFC WAVE CROSSING SC THEN UP ALONG THE NC COAST...PLACING CENTRAL NC
IN THE COOL SECTOR. THE LATER SOLUTION SEEMS MORE LIKELY CONSIDERING
THE POTENTIAL FOR A SHALLOW LAYER OF COOL AIR TO ADVECT INTO THE
REGION BEHIND THE INITIAL PERTURBATION. HAVE TRENDED MAX TEMPS A
LITTLE COOLER THAN MOS GUIDANCE BUT LATER FORECASTS MAY NEED TO
TREND COOLER.
TUESDAY THROUGH FRIDAY WILL FEATURE MAINLY DRY WEATHER WITH A
COOLING TREND AS BROAD UPPER LEVEL TROUGH COVERS THE U.S. THE WLY
FLOW ALOFT AND SFC HIGH PRESSURE DIVING SOUTHWARD ACROSS THE CENTRAL
U.S. NORMALLY SIGNALS DRY AND SEASONABLY COOL CONDITIONS FOR OUR
REGION. MAX TEMPS BY THE NEW YEAR WILL AVERAGE IN THE 40S TO NEAR 50
WITH MIN TEMPS IN THE 20S TO AROUND 30.
&&
.AVIATION /06Z SATURDAY THROUGH TUESDAY/...
AS OF 100 AM SATURDAY...
WITH DEWPOINTS SLIGHTLY HIGHER OVER THE COASTAL PLAIN AND LIGHT
WINDS...THERE MAY BE A COUPLE HOURS OF MVFR VSBY AT KRWI AND/OR KFAY
PRIOR TO 12Z...ESPECIALLY AS SKIES PARTIALLY CLEAR BETWEEN SOME HIGH
CLOUDS MOVING OVERHEAD. OTHERWISE.. VFR CONDITIONS ARE EXPECTED TO
CONTINUE THROUGH THE TAF PERIOD WITH LIGHT WINDS BECOMING SOUTH-
SOUTHWESTERLY DURING THE DAY.
MID-LEVEL CLOUDS WILL INCREASE LATER TONIGHT AND EARLY SUNDAY AHEAD
OF A DISTURBANCE MOVING ALONG THE APPALACHIANS. HOWEVER...CURRENT
MODEL PROJECTIONS HAVE LOW CLOUDS AND SUB-VFR CEILINGS SPREADING
INTO THE KGSO/KINT VICINITY WELL AFTER 06Z SUNDAY.
LOOKING AHEAD: A SERIES OF UPPER-LEVEL DISTURBANCES MOVING SOUTHWEST
TO NORTHEAST ACROSS THE REGION COMBINED WITH AN APPROACHING FRONTAL
ZONE WILL BRING A COUPLE ROUNDS OF LIGHT PRECIP AND SUB-VFR
CONDITIONS TO PORTIONS OF CENTRAL NC SUNDAY AND MONDAY. CONDITIONS
ARE EXPECTED TO IMPROVE BY LATE MONDAY NIGHT INTO TUESDAY. -KRD
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BLS
NEAR TERM...HARTFIELD/KRD
SHORT TERM...WSS
LONG TERM...WSS
AVIATION...BLS
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
402 AM CST SAT DEC 27 2014
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 402 AM CST SAT DEC 27 2014
SKY COVER AND RELATED TEMPERATURES WILL BE THE FORECAST CHALLENGE
FOR TODAY AND TONIGHT. EASTERN NORTH DAKOTA IS CURRENTLY SEEING AN
INCREASE IN CLOUD COVER AND FILLING IN A BAND OF CLEAR SKIES FROM
ABOUT THE RRV TO DEVILS LAKE. THAN NAM12 AND RUC13 MODELS ARE
DOING A DECENT JOB DEPICTING THE CLEAR BAND AND USED THOSE MODELS
FOR GUIDANCE. ANOTHER CHALLENGE WILL BE ASSOCIATED LIGHT SNOW OR
FLURRIES AS SOME WEAK VORTICES MOVE ACROSS SRN CANADA.
TODAY...LOW CLOUDS TO THE EAST WILL PROGRESS SLOWER THAN THE
CLOUDS MOVING IN FROM THE WEST AND FILL IN THE CLEAR GAP OVER
NORTHEASTERN ND BY MID MORNING. SOME LIGHT SNOW NOW JUST EAST OF
MINOT WILL TRACK ACROSS NORTHERN ND AND INTO N CNTRL MN...AND
MODELS ARE SHOWING THIS MOVING EAST OF CWA BY 21Z. HAVE INTRODUCED
SOME LOW POPS AND ISOLATED SHSN FOR THIS AS WV IS SHOWING A COUPLE
OF WAVES MOVING ACROSS SRN CANADA THAT ARE PROVIDING ENOUGH LIFT
TO GENERATE SOME LIGHT SNOW. EXPECT NO MORE THAN A COUPLE OF
TENTHS OF AN INCH OF FLUFF ACROSS THE FAR NORTH...AND RATHER
SPOTTY IN NATURE. SOUTHERN ZONES WILL BE MORE CHALLENGING AS SAT
TRENDS DO NOT GIVE ME A LOT OF CONFIDENCE THAT THE SRN VALLEY WILL
SEE CLOUDS MOVE IN...AND IF IT REMAINS CLEAR COULD BE WARMER THAN
FCST HIGHS.
TONIGHT...AN ARCTIC AIRMASS WILL BEGIN SINKING SOUTH AND THE DRIER
AIR SHOULD HELP CLEAR THINGS OUT AT LEAST IN THE NORTH. WILL SEE A
LARGE TEMP GRADIENT ACROSS CWA FROM NW TO SE AS LINGERING CLOUDS
IN THE FAR SE COULD KEEP OVERNIGHT LOWS IN THE LOW TEENS WHEREAS
THE NW SHOULD SEE TEMPS FALL INTO DOUBLE DIGITS BELOW ZERO AS THE
COLD AIRMASS DROPS INTO THE REGION.
SUNDAY...ARCTIC AIR MASS SINKING SOUTH WILL BRING AN INCREASE IN
SOLAR BUT MUCH COLDER AND DRIER AIR. DAYTIME HIGHS WILL STRUGGLE
TO RECOVER TO ABOVE ZERO TEMPS ACROSS THE NORTH...WHILE THE
SOUTHERN ZONES WILL LIKELY SEE EARLY HIGHS AS EARLY MORNING CLOUDS
KEEP SAT NIGHT LOWS IN THE MID TEENS PRIOR TO COLDER AIR MAKING IT
TO THE SOUTHERN ZONES. SHOULD SEE STEADY TO FALLING TEMPS IN THE AFTN.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 402 AM CST SAT DEC 27 2014
SUNDAY NIGHT THROUGH MONDAY NIGHT...SFC HIGH WILL MOVE OVER MT AND
DAKOTAS AND MN SHOULD SEE LIGHT NW FLOW...WHICH WILL KEEP MON
NIGHT LOWS FROM PLUMMETING TOO FAR BUT DOUBLE DIGITS BELOW ZERO
TEMPS ARE EXPECTED. ADDITIONALLY THE LIGHT NW WINDS WILL BE
SUFFICIENT TO BRING WIND CHILLS TO ADVISORY LEVELS BOTH MON AND
TUE MORNING. THE COLD APPARENT TEMPS BOTH MORNINGS WILL BE THE
MOST SIGNIFICANT WX HAZARD WITHIN THE SHORT TERM PERIOD.
WEDNESDAY THROUGH SATURDAY...THE DEEP LONG WAVE TROF OVER CENTRAL NOAM
EARLY IN THE WEEK SHOWS A DISTINCT SHIFT INTO THE EAST AT MIDWEEK
AND A RETURN TO A MORE ZONAL FLOW PATTERN ACROSS THE NORTHERN
PLAINS BY THE LATE WEEK PERIOD. EXPECT ARCTIC AIRMASS TO MODERATE
TO NEAR SEASONAL NORMALS WED INTO FRI...WITH AN ADDITIONAL SHOT OF
COLD AIR MOVING IN BY THE WEEK END. PRECIPITATION CHANCES ARE LOW
THROUGH THE PERIOD WITH OCCASIONAL LIGHT SNOW OR FLURRIES
POSSIBLE LATE THURSDAY INTO SATURDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1143 PM CST FRI DEC 26 2014
MVFR CONDITIONS CONTINUE AT KGFK...KTVF...AND KBJI ALONG WITH AN
ISOLATED FLURRY AT TIMES AT KBJI. KDVL IS CURRENTLY CLEAR BUT WILL
CLOUD UP IN THE NEXT HOUR OR SO AS CLOUDS MOVE IN FROM THE WEST.
CURRENT OBS OVER CENTRAL AND WESTERN ND HAVE THE LEADING EDGE OF
CLOUDS MAINLY IN THE 5000-7000 FT RANGE SO THINK VFR CONDITIONS
WILL CONTINUE A BIT LONGER. MVFR CIGS ARE FURTHER BEHIND
THOUGH...AND THINK ALL TAF SITES SHOULD GO DOWN IN CATEGORY BY MID
MORNING TOMORROW. THINK THAT THE STRATUS WILL STICK AROUND FOR THE
AFTERNOON AND EVENING. THE ARCTIC FRONT WILL BEGIN TO MOVE DOWN
INTO THE FORECAST AREA BY THE END OF THE PERIOD...WITH CLOUDS AND
EVEN SOME LIGHT SNOW POSSIBLE ALONG THE LEADING EDGE.
HOWEVER...UNCERTAIN WHERE THE SNOW WILL BE SO WILL LEAVE OUT FOR
NOW. MVFR CONDITIONS WILL CONTINUE THROUGH THE END OF THE PERIOD.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
SHORT TERM...SPEICHER
LONG TERM...GUST/SPEICHER
AVIATION...JR
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1143 PM CST FRI DEC 26 2014
.UPDATE...
ISSUED AT 1143 PM CST FRI DEC 26 2014
SFC RIDGE AXIS HAS SETTLED OVER THE CENTER OF THE CWA...BUT THE
CLOUDS HAVE MOVED LITTLE FURTHER EASTWARD FROM THE RED RIVER AT
LEAST IN THE NORTHERN VALLEY. THERE ARE SOME MID LEVEL CLOUDS
STARTING TO MOVE INTO THE NORTHWESTERN COUNTIES...SO THE FREE FALL
OF BELOW ZERO TEMPS FROM DVL AND POINTS NORTH SHOULD START TO
LEVEL OFF. THINK THAT THE CLOUDS WILL CONTINUE TO MOVE EAST...WITH
THE WESTERN DECK FASTER AND POSSIBLY OVERTAKING THE EASTERN DECK
WHICH HAS BEEN SLOW TO BUDGE. CONTINUED TO KEEP SOME CLEARING IN
THE VALLEY TOWARDS MORNING BUT MAY HAVE TO ADJUST IF THE DRYING
NEVER MAKES IT INTO THE CENTRAL CWA.
UPDATE ISSUED AT 949 PM CST FRI DEC 26 2014
STRATUS HAS REMAINED OVER THE NORTHERN RED RIVER VALLEY AND IS
EVEN SPITTING OUT SOME MORE FLURRIES. MUCH OF THE WESTERN CWA HAS
REMAINED CLEAR AND SOME SPOTS IN THE NORTHWEST HAVE DROPPED DOWN
TO THE -5 TO -10 RANGE. THINK THAT THE COLDEST AREAS COULD BOTTOM
OUT AROUND -10 BUT CLOUDS ARE STARTING TO MOVE IN FROM THE WEST SO
THEY SHOULD SLOWLY START TO RISE AFTER MIDNIGHT. TRIED TO ADJUST
CLOUDS TO REFLECT CURRENT TRENDS AND FOLLOW THE RAP WHICH HAS BEEN
NOT TOO FAR OFF...THE CLEAR AREA MOVING EAST INTO THE VALLEY
TOWARDS MORNING WHILE THE WEST CLOUDS UP AGAIN. EXTENDED THE
FLURRY MENTION...PUTTING ISOLATED OR SCATTERED WHEREVER THE CLOUDS
ARE OVERNIGHT.
UPDATE ISSUED AT 655 PM CST FRI DEC 26 2014
CLOUDS WILL BE THE MAIN ISSUE...AS THE NORTHERN VALLEY HAS SEEN A
BIT MORE CLOUDS MOVING DOWN OUT OF CANADA...BUT THE WEST CONTINUES
TO BE CLEAR. TEMPS JUST NORTH OF LANGDON ARE ALREADY DOWN AROUND
MINUS 8...SO THINK PREVIOUS SHIFTS IDEA OF A SHARP DROP OFF AND
THEN RISING TEMPS LATER ON AS MORE CLOUDS COME IN FROM THE WEST.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 305 PM CST FRI DEC 26 2014
HIGH PRESSURE WILL BUILD INTO THE REGION TONIGHT. CLOUDS HAVE BEEN
SLOW TO CLEAR FROM THE NORTHWEST...BUT THE CLEARING CONTINUES TO
MAKE PROGRESS FROM WEST TO EAST. RAP/HRRR GUIDANCE CLEARS AREAS
ALONG AND WEST OF THE VALLEY BY THIS EVENING...BUT KEEPS AREAS
EAST OF THE VALLEY CLOUDY THROUGH THE OVERNIGHT. TRENDED SLOWER
WITH THE CLEARING EAST OF THE VALLEY...BUT STILL KEPT THE IDEA
FOR CLEARING BY MORNING (LATER UPDATES WILL NEED TO EVALUATE IF
THE HRRR/RAP IDEA MIGHT BE BETTER). MIN TEMPERATURES WILL BE EVEN
TRICKIER...MUCH DEPENDENT ON CLOUD COVER. THERE SHOULD BE A QUICK
DROP THIS EVENING WHERE SKY IS CLEAR...BUT WARM AIR
ADVECTION/RETURN FLOW KICKS IN AFTER MIDNIGHT WHICH SHOULD STEADY
OR SLOWLY RISE TEMPS (AT LEAST FOR THE DVL BASIN...NOT SURE ABOUT
VALLEY LOCATIONS).
COLD FRONT POISED TO DROP THROUGH THE FA SATURDAY NIGHT. ONE LAST
WARMER DAY ON SATURDAY AHEAD OF THIS FEATURE...WITH CLOUDS
INCREASING FROM NORTH TO SOUTH. THIS FROPA WILL BE ASSOCIATED WITH
WEAK FORCING...SO ISOLD SNOW SHOWERS/FLURRIES POSSIBLE. MODELS
INDICATE THAT COLD AIR ADVECTION WILL BE RELATIVELY WEAK...LEADING
TO A SHALLOW MIXING LAYER WITH 15-20 KNOTS AVAILABLE TO MIX
(WINDS MAYBE BREEZY...BUT NOT STRONG).
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 305 PM CST FRI DEC 26 2014
SUNDAY-MONDAY NIGHT...COLD AIR ADVECTION REGIME WITH HIGH
PRESSURE BUILDING INTO THE REGION. TEMPERATURES WILL BE MUCH
COLDER THAN THE PREVIOUS COUPLE WEEKS...WITH MAX TEMPS MAINLY IN
THE SINGLE DIGITS (ABOVE OR BELOW ZERO)...AND MIN TEMPS MAINLY
BELOW ZERO. THE MAIN CONCERN THIS PERIOD WILL BE WIND CHILL
VALUES. THE STRONGEST AREA OF HIGH PRESSURE WILL TRACK ACROSS THE
WESTERN DAKOTAS...KEEPING THIS REGION WITHIN A WEAK SFC PRESSURE
GRADIENT. THIS SHOULD BE ENOUGH FOR WIND SPEEDS AOA 5 KNOTS SUNDAY
NIGHT AND MONDAY NIGHT WHEN TEMPERATURES WILL BE THE COLDEST
(LEADING TO POTENTIAL WIND CHILL ADVISORY CONDITIONS).
TUESDAY-FRIDAY...LONG WAVE RIDGE FORECAST TO REMAIN OVER WESTERN
NORTH AMERICA INTO AK WHILE LONG WAVE TROUGH EXTENDS FROM HUDSON
BAY TO THE DESERT SOUTHWEST. LONG WAVE TROUGH SHIFTS OVER EASTERN
NORTH AMERICA BY THE END OF THE PERIOD. LONG WAVE UPPER RIDGE
DEAMPLIFIES WHILE LONG WAVE TROUGH OVER HUDSON BAY AMPLIFIES
THROUGH THE PERIOD.
ECMWF AND GFS WERE IN GOOD AGREEMENT AT THE BEGINNING OF THE PERIOD.
THE GFS WAS A LITTLE FASTER AND BECOMES FASTER THAN THE ECMWF FOR
THE REST OF THE PERIOD. WILL PREFER THE SLOWER ECMWF.
WILL SPLIT THE DIFFERENCE BETWEEN POPS FROM THIS MORNINGS PACKAGE
AND POPS FOR THIS AFTERNOONS RUN FOR WED NIGHT AND THU.
A COLD DAY TO START ON TUE. SOME MODERATION ON WED AND THU, THEN BACK
INTO ARCTIC AIR ON FRI. HIGH TEMPS WERE GENERALLY INCREASED A DEGREE
OR TWO FOR TUE AND WED, INCREASED ONE TO FOUR DEGREES ON THU AND
LITTLE CHANGE ON FRI.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1143 PM CST FRI DEC 26 2014
MVFR CONDITIONS CONTINUE AT KGFK...KTVF...AND KBJI ALONG WITH AN
ISOLATED FLURRY AT TIMES AT KBJI. KDVL IS CURRENTLY CLEAR BUT WILL
CLOUD UP IN THE NEXT HOUR OR SO AS CLOUDS MOVE IN FROM THE WEST.
CURRENT OBS OVER CENTRAL AND WESTERN ND HAVE THE LEADING EDGE OF
CLOUDS MAINLY IN THE 5000-7000 FT RANGE SO THINK VFR CONDITIONS
WILL CONTINUE A BIT LONGER. MVFR CIGS ARE FURTHER BEHIND
THOUGH...AND THINK ALL TAF SITES SHOULD GO DOWN IN CATEGORY BY MID
MORNING TOMORROW. THINK THAT THE STRATUS WILL STICK AROUND FOR THE
AFTERNOON AND EVENING. THE ARCTIC FRONT WILL BEGIN TO MOVE DOWN
INTO THE FORECAST AREA BY THE END OF THE PERIOD...WITH CLOUDS AND
EVEN SOME LIGHT SNOW POSSIBLE ALONG THE LEADING EDGE.
HOWEVER...UNCERTAIN WHERE THE SNOW WILL BE SO WILL LEAVE OUT FOR
NOW. MVFR CONDITIONS WILL CONTINUE THROUGH THE END OF THE PERIOD.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...JR
SHORT TERM...TG
LONG TERM...TG/HOPPES
AVIATION...JR
AREA FORECAST DISCUSSION
NWS NORMAN OK
129 AM CST SAT DEC 27 2014
.UPDATE...
UPDATE TO PRECIP/WX THROUGH 12Z...
&&
.DISCUSSION...
QUICK MORNING UPDATE FOR PRECIP/WX THROUGH 12Z THIS MORNING.
OBSERVING RADAR TRENDS AND LIMITED REPORTS FROM MPING THIS AM...
THE NARROW LINE OF PRECIP THAT HAS DEVELOPED BETWEEN THE I-44 AND
I-35 CORRIDORS IS PRIMARILY RAIN... WITH SOME SLEET/SNOW MIXED
IN. A FEW MPING REPORTS AND RAP BUFR SOUNDINGS SUPPORT THIS... AS
A WARM LAYER REMAINS PRESENT AROUND 800-850MB. SFC TEMPS REMAIN
WELL ABOVE FREEZING... SO EXPECT NO ISSUES WITH REGARDS TO TRAVEL.
07Z SFC ANALYSIS HAS THE COLD FRONT PUSHING INTO FAR SERN OK...
WITH THE FREEZING LINE NEAR AN ERICK TO WATONGA TO CHEROKEE LINE
IN NWRN OK. GUIDANCE FROM THE HRRR... RAP AND WRF STILL DEVELOP A
LIGHT BAND OF SNOW FROM SWRN OK INTO CENTRAL OK THROUGH SUNRISE.
ANY ACCUMULATIONS WILL BE MINOR... A DUSTING TO A QUARTER OF AN
INCH AS SFC TEMPS WILL REMAIN AT OR JUST ABOVE FREEZING. 2 INCH
SOIL TEMPS FROM THE OKMESONET AT 115 AM ARE STILL IN THE LOW TO
MID 40S. EXPECT MINOR TO NO IMPACT ON TRAFFIC AT THIS TIME.
JTK
&&
.PREV DISCUSSION... /ISSUED 914 PM CST FRI DEC 26 2014/
UPDATE...
MADE MINOR ADJUSTMENTS TO POPS OVERNIGHT AS RADAR TRENDS SUGGEST
CHANCES FOR -SN HAVE DECREASED SOMEWHAT ACROSS FAR NORTHWESTERN
OKLAHOMA. ALSO INTRODUCED ISO THUNDER OVER SOUTH CENTRAL OK WITH
RECENT HEAVY SHOWER DEVELOPMENT. OTHERWISE...THE FORECAST IS
LARGELY UNCHANGED. STILL EXPECT LIGHT SNOW OR A MIX OF RAIN/SNOW
FROM ROUGHLY I-44 WEST THROUGH SATURDAY AM. ACCUMULATIONS IF
ANY...WILL BE QUITE LOW...THOUGH ANY SNOWBANDS THAT DEVELOP MAY
LOCALLY LEAD TO A DUSTING TO QUARTER INCH OF SNOW FROM
NORTHWESTERN THROUGH WEST CENTRAL AND SOUTHWESTERN OKLAHOMA.
IMPACTS SHOULD BE MINOR GIVEN GROUND TEMPS ABOVE FREEZING...BUT
EXPOSED ROADS SUCH AS BRIDGES AND OVERPASSES MAY BECOME SLICK IN A
FEW PLACES THAT SEE LIGHT SNOW ACCUMULATIONS.
PREV DISCUSSION... /ISSUED 520 PM CST FRI DEC 26 2014/
AVIATION...
COLD FRONT NEAR I-44 CORRIDOR WILL CONT TO PUSH SOUTHEAST THIS
EVENING WITH NORTH WINDS THROUGH REMAINDER OF FORECAST. A FEW
GUSTS ACROSS SOUTHWEST SITES MAY EXCEED 20KTS THIS EVENING.
OTHERWISE MVFR CEILINGS EXPECTED TO GIVE WAY TO MAINLY CLEAR
SKIES DURING THE DAY ON SATURDAY... ESPECIALLY BY AFTN. THERE
IS A CHANCE FOR SOME LIGHT SNOW ACROSS NORTHWEST THIS EVENING
AND LIGHT RAIN NEAR I-44 CORRIDOR... HOWEVER CHANCES REMAIN TOO
LOW TO MENTION IN FORECAST AT THIS TIME.
30
PREV DISCUSSION... /ISSUED 321 PM CST FRI DEC 26 2014/
DISCUSSION...
A WAVE IS LIFTING NORTHEAST FROM THE ROCKIES INTO THE CENTRAL
PLAINS TODAY. MUCH OF THE PRECIPITATION THAT IS OBSERVED ON RADAR
IN THE EASTERN TEXAS PANHANDLE IS VIRGA AS LOW LEVELS REMAIN DRY
IN THE SOUTHEASTERN PANHANDLE. THERE IS A BIT MORE LOW LEVEL
MOISTURE IN THE NORTHEASTERN PANHANDLES AND NORTHWESTERN OKLAHOMA
AS EVIDENCED BY THE STRATUS... SO WILL KEEP CHANCE POPS THERE.
WILL ALSO KEEP CHANCE POPS EAST WHERE SOME LIGHT RAIN/DRIZZLE
DEVELOPMENT. BUT OVERALL FOR TONIGHT AND TOMORROW... IT DOES NOT
LOOK LIKE TOO SIGNIFICANT OF AN EVENT OVER THE AREA AND WILL
CONTINUE TO TREND OF DECREASING POPS AND EXPECTED PRECIPITATION
AMOUNTS.
THE OTHER MAIN WEATHER ISSUE IS EXPECTED TO BE THE SIGNIFICANTLY
COLDER WEATHER NEXT WEEK. THE FORECAST STILL LOOKS GOOD WITH THIS
AND DID NOT MAKE ANY SIGNIFICANT CHANGES IN THE EXTENDED.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 39 25 46 28 / 20 0 0 0
HOBART OK 40 22 46 26 / 10 0 0 0
WICHITA FALLS TX 42 26 48 31 / 20 0 0 0
GAGE OK 37 18 45 20 / 0 0 0 0
PONCA CITY OK 39 22 43 25 / 10 0 0 0
DURANT OK 44 29 47 31 / 30 10 10 0
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
04/23
AREA FORECAST DISCUSSION
NWS PORTLAND OR
855 PM PST FRI DEC 26 2014
.SYNOPSIS...A FEW SHOWERS WILL CONTINUE NORTH OF THE COLUMBIA RIVER
OVERNIGHT. THEN RAIN AND MODERATE TO HEAVY MOUNTAIN SNOW WILL SPREAD
INTO SOUTHWEST WASHINGTON AND FAR NORTHWEST OREGON LATE TONIGHT AND
ACROSS THE AREA SATURDAY AS A COOL SYSTEM DROPS IN FROM THE
NORTHWEST. A TRAILING SECONDARY WAVE WILL MAINTAIN SHOWERS SUNDAY
INTO MONDAY. COLDER AND DRIER WEATHER WITH OFFSHORE WINDS WILL BEGIN
TO FILTER IN ON MONDAY AND KICK IN IN EARNEST MONDAY NIGHT AND
TUESDAY...CONTINUING THROUGH AT LEAST THE MID WEEK PERIOD. THE NEXT
CHANCE OF SOME PRECIPITATION MAY BE LATE IN THE WEEK OR NEXT
WEEKEND.
&&
.SHORT TERM...TONIGHT THROUGH MONDAY...A FEW SHOWERS CONTINUE TO
LINGER THIS EVENING ALONG THE NORTH COASTAL AREAS AND INTO THE SOUTH
WASHINGTON CASCADES...THOUGH THEY HAVE DECREASED SOME FROM EARLIER
THIS EVENING. ATTENTION THEN TURNS TO THE SYSTEM DROPPING SOUTH
THROUGH B.C. THIS EVENING. THIS COOL SYSTEM WILL START TO SPREAD SOME
RAIN AND MOUNTAIN SNOW INTO OUR FAR NORTH ZONES AFTER MIDNIGHT
TONIGHT...THEN SPREAD ACROSS THE ENTIRE AREA DURING THE DAY ON
SATURDAY. THERE IS A DECENT 100 KT UPPER JET WITH IT AND AMPLE
ONSHORE FLOW...SO WE SHOULD SEE ANOTHER ROUND OF DECENT SNOWS IN THE
CASCADES. WILL CONTINUE THE SNOW ADVISORIES.
THE FIRST MAIN FRONT MOVES THROUGH SATURDAY AFTERNOON AND EVENING...
BUT THEN THE MODELS SHOW CONTINUING ONSHORE FLOW AND ANOTHER SHORT
WAVE LATER SUNDAY INTO MONDAY FOR MORE VALLEY RAIN SHOWERS AND
MOUNTAINS SNOW. THE HEAVIEST SNOWFALL RATES LOOK TO BE SATURDAY AND
SATURDAY NIGHT WITH AMOUNTS RANGING FROM 8 TO 14 INCHES NORTH TO 4
TO 8 INCHES SOUTH...BUT WE SHOULD STILL GET SOME ACCUMULATING SNOW
IN THE CASCADES ON SUNDAY INTO SUNDAY NIGHT THAT MAY STILL IMPACT
TRAFFIC. AMOUNTS WILL BE MORE IN THE 1 TO 3 TO 2 TO 4 INCH RANGE
SUNDAY AND POSSIBLY AGAIN SUNDAY NIGHT. HAVE UPPED POPS SOME THOSE 2
FORECAST PERIODS.
THE PRECIPITATION WILL BE DECREASING FROM THE NORTH MONDAY AS DRIER
AND COLDER AIR STARTS TO FILTER IN...AND SOME EAST WINDS START TO
DEVELOP IN THE GORGE. THE MAIN PERIOD OF STRONGER EAST WIND WILL
DEVELOP MONDAY NIGHT AND CONTINUE THROUGH THE MID WEEK PERIOD...
USHERING IN MUCH COLDER WEATHER ACROSS THE FORECAST AREA. TOLLESON
.LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS...
MONDAY NIGHT THROUGH THURSDAY NIGHT...A PERSISTENT WEATHER PATTERN
WILL SET UP EARLY NEXT WEEK AS A REX BLOCK DEVELOPS WITH STRONG HIGH
PRESSURE ALOFT OVER THE PACIFIC NW AND AN UPPER LOW OVER THE CA/AZ.
TEMPERATURES ARE EXPECTED TO DRAMATICALLY DROP MONDAY NIGHT WITH LOWS
AROUND 30 FOR THE COAST...LOW TO MID 20S FOR THE INTERIOR
VALLEYS...AND BELOW 20 FOR THE CASCADES AND CASCADE FOOTHILLS.
DAYTIME HIGHS BEGINNING TUESDAY WILL REMAIN NEAR OR BELOW FREEZING
FOR MANY LOCATIONS...WITH THE EXCEPTION OF THE COAST BEING SLIGHTLY
WARMER. THESE COLD TEMPERATURES ALONG WITH NORTHEAST WINDS WILL
PERSIST THROUGH WEDNESDAY. THE MODELS ARE SHOWING THE BLOCKING
PATTERN DISINTEGRATING THU...ENDING THE OFFSHORE WINDS AND ALLOWING
TEMPERATURES TO RECOVER A LITTLE BIT BY FRIDAY. MODELS TEND TO BREAK
DOWN THESE BLOCKS TOO EARLY AND THERE IS A CHANCE THAT THE VERY COLD
CONDITIONS WILL PERSIST A DAY OR TWO LONGER. BOWEN/TJ
&&
.AVIATION... OVERALL GENERAL IMPROVEMENT IN FLIGHT CONDITIONS THIS
EVENING. NEARLY ALL METAR SITES ARE VFR AS OF 04Z. THE EXCEPTION IS
THE EXTREME N OREGON AND S WA COAST WHERE IFR EXISTS. EXPECT A RETURN
TO MAINLY MVFR CIGS OVERNIGHT...WITH LOCALIZED IFR CONDITIONS IN THE
INTERIOR VALLEYS. NOT LOOKING FOR ANY EXTENDED CLEARING PERIODS
OVERNIGHT THUS LIFR NOT EXPECTED. LATEST NAM AND HRRR MODELS SHOW THE
LEADING EDGE OF THE PRECIP SHIELD REACHING THE S WA AND N OREGON
COAST AROUND 12-14Z. WILL GO WITH IFR TO MVFR AT KAST STARTING AROUND
THAT TIME. PRECIP SPREADS SE SAT MORNING WITH INCREASING MVFR. THERE
MAY BE SOME AREAS OF IFR WITH THE INITIAL PRECIP DUE TO LIMITED WIND.
HOWEVER...SURFACE GRADIENTS PICK UP DURING THE MORNING...WHICH SHOULD
PRODUCE ENOUGH MIXING IN THE INTERIOR VALLEYS TO ELIMINATE IFR.
HIGHER TERRAIN BECOMES OBSCURED SAT AFTERNOON THROUGH THE EVENING AS
850 MB WLY WIND INCREASES.
KPDX AND APPROACHES...CONDITIONS HAVE IMPROVED TO VFR THIS EVENING
BUT STILL EXPECT A RETURN TO PREDOMINANT MVFR OVERNIGHT. INITIAL
PRECIP LOOKS TO REACH THE TERMINAL AND VICINITY 14-16Z SAT. THERE IS
THE POSSIBILITY OF IFR WITH THE INITIAL PRECIP DUE TO WEAK SURFACE
GRADIENTS. HOWEVER...SURFACE WIND SHOULD PICK UP MID TO LATE MORNING
RESULTING MVFR TO LOW-END VFR CONDITIONS THRU THE AFTERNOON AND
EVENING HOURS. WEISHAAR
&&
.MARINE...HIGH PRESSURE OVER THE WATERS WILL WEAKEN OVERNIGHT AS THE
NEXT FRONTAL SYSTEM DROPS S ALONG THE BRITISH COLUMBIA COAST. LATEST
NAM RUN PRETTY CONSISTENT WITH ITS PREVIOUS VERSION SHOWING 20 TO 25
KT WIND DEVELOPING OVER THE FAR NRN WATERS AROUND 20Z SAT. THE WIND
GRADUALLY INCREASES OVER ALL WATERS SAT AFTERNOON AND EVENING...WITH
LOCALIZED GUSTS TO 35 KT POSSIBLE OVER THE NRN WATERS 00Z SUN THROUGH
AT LEAST 12Z SUN. HAVE OPTED TO GO WITH SEPARATE SMALL CRAFT
ADVISORIES FOR WIND...STARTING IN THE NRN WATERS 20Z SAT BUT HOLDING
OFF IN THE SRN WATERS UNTIL 23Z. ALSO ENDED THE ADVISORY A BIT SOONER
IN THE SRN WATERS. THE NWLY WIND GRADUALLY WEAKENS SUN EVENING AND
SUN NIGHT. MODELS ARE IN GOOD AGREEMENT ON THE TRANSITION TO
OFF-SHORE WIND BEGINNING MON AFTERNOON. WILL NEED TO WATCH FOR SMALL
CRAFT ADVISORY WIND MON NIGHT THROUGH AT LEAST MID-WEEK.
SEAS TO RAMP UP AGAIN WITH THE NEXT FRONTAL SYSTEM. THERE MAY BE A
DYNAMIC FETCH SET UP WITH THIS NEXT ONE...WHICH MEANS THE WAVE
GUIDANCE MAY BE A LITTLE UNDERDONE WITH THE OVERALL WAVE HEIGHTS.
SEAS SHOULD PEAK IN THE 14-17 FT RANGE IN THE NRN WATERS LATE SAT
NIGHT OR SUN MORNING. THIS DOES NOT LOOK LIKE A LONG-DURATION FETCH
SITUATION SO THE TIME FRAME FOR MAX SEAS SHOULD BE ON THE ORDER OF 5
TO 10 HOURS. SEAS FALL BELOW 10 FT LATE SUN NIGHT OR MON MORNING AND
REMAIN WELL BELOW 10 FT FOR MUCH OF THE WEEK. WEISHAAR
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...WINTER WEATHER ADVISORY FROM 10 AM SATURDAY TO 10 AM PST SUNDAY
FOR CASCADES IN LANE COUNTY-NORTHERN OREGON CASCADES.
WA...WINTER WEATHER ADVISORY FROM 4 AM SATURDAY TO 4 AM PST SUNDAY
FOR SOUTH WASHINGTON CASCADES.
PZ...SMALL CRAFT ADVISORY FOR WINDS FROM NOON SATURDAY TO 10 PM PST
SUNDAY FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO CASCADE
HEAD OR OUT 60 NM.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 2 PM SATURDAY TO 9
AM PST MONDAY FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO
FLORENCE OR OUT 60 NM.
SMALL CRAFT ADVISORY FOR WINDS FROM 3 PM SATURDAY TO 6 PM PST
SUNDAY FOR COASTAL WATERS FROM CASCADE HEAD OR TO FLORENCE OR
OUT 60 NM.
SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR UNTIL 10 PM
PST THIS EVENING.
SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR FROM 4 PM TO
10 PM PST SATURDAY.
&&
$$
INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/NWSPORTLAND
WWW.TWITTER.COM/NWSPORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON
FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS
COMMONLY REFERRED TO AS THE FORECAST AREA.
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1109 PM CST FRI DEC 26 2014
.DISCUSSION...
SEE THE 06Z AVIATION DISCUSSION BELOW.
40
&&
.AVIATION...
THE COLD FRONT OVER THE NORTHWESTERN PART OF THE STATE IS EXPECTED
TO REACH KCLL AND KUTS BY AROUND 13Z. LIKED A BIT FASTER PASSAGE
OF THE FRONT THAT EARLIER FORECASTED OVER THE REMAINING SITES AND
WENT MORE WITH THE LATEST RAP13 MODEL. THIS MEANS THE FRONT IS NOW
EXPECTED TO REACH KCXO BY 20Z...KIAH BY 21Z...AND KHOU BY 23Z. THE
FRONT SHOULD MAKE ITS WAY THROUGH KLBX AND KGLS BETWEEN 00Z AND
01Z. MVFR TO IFR CONDITIONS WILL DEVELOP AHEAD OF THE FRONT AND
SEA FOG FORMING SOUTH OF THE LOUISIANA COAST MAY WORK ITS WAY INTO
KGLS BY 14Z. IF SO...THE FOG WILL LIKELY LINGER IN PLACE UNTIL
SOUTHWESTERLY WINDS DEVELOP AROUND 20Z. THUNDERSTORMS ARE LIKELY
AHEAD OF THE FRONT AS IT MOVES INTO THE KCXO AND KIAH SITES
SOUTHWARD TO THE COAST.
BEHIND THE FRONT NORTHWESTERLY WINDS WILL DEVELOP...AND THEN
BECOME BREEZY BETWEEN 2 AND 4 HOURS LATER. ISENTROPIC LIFT WILL
LIKELY KEEP AT LEAST MVFR CONDITIONS IN PLACE BEHIND THE FRONT.
40
&&
.PREV DISCUSSION... /ISSUED 934 PM CST FRI DEC 26 2014/
UPDATE...
SEE DISCUSSION FOR EVENING UPDATE.
DISCUSSION...
ONLY MINOR CHANGES TO THE FORECAST THIS EVENING. COLD FRONT IS NOW
PAST LUBBOCK AND IS FORECASTED TO BE AT COLLEGE STATION AROUND 9
AM TOMORROW MORNING. THE FRONT IS THEN FORECASTED TO BE AT HOUSTON
BETWEEN 2 AND 4 PM. A CONVERGENCE ZONE HAS SET UP THIS EVENING
RIGHT AROUND THE COAST UP INTO HARRIS AND LIBERTY COUNTIES. HIGH
RES MODELS HAVE STRUGGLED WITH THIS PRECIP. NEW RAP SEEMS TO BE
CATCHING ON WITH THE CURRENT TRENDS. GENERAL THINKING IS FOR THE
PRECIP TO PUSH TOWARDS THE NORTH AND EXPAND IN COVERAGE AHEAD OF
THE FRONT. NEW 0Z LCH SOUNDING HAS A PRETTY GOOD CAP AROUND 700 MB
SO EXPECT MOST PRECIP TO REMAIN THUNDER FREE OVERNIGHT. GFS AND
NAM SOUNDINGS ERODE THE CAP A BIT AND SUPPORT THUNDER FOR THE
AFTERNOON. BEHIND THE FRONT EXPECT TEMPERATURES TO FALL TOMORROW.
23
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 62 63 42 53 38 / 50 60 40 20 10
HOUSTON (IAH) 65 72 47 53 40 / 60 70 50 40 10
GALVESTON (GLS) 66 70 50 53 48 / 50 70 70 60 10
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT SHOULD EXERCISE CAUTION UNTIL 3 AM CST SATURDAY FOR
THE FOLLOWING ZONES: WATERS FROM FREEPORT TO THE MATAGORDA
SHIP CHANNEL 20 NM TO 60 NM...WATERS FROM HIGH ISLAND TO
FREEPORT 20 TO 60 NM.
&&
$$
DISCUSSION...23
AVIATION/MARINE...40
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
544 AM CST SAT DEC 27 2014
.SHORT TERM...
245 AM CST
THROUGH SUNDAY...
WE ARE LIVING ON BORROWED TIME WITH 850 MB TEMPS SITTING ABOVE
ZERO...BUT THAT WILL BE A THING OF THE PAST COME THIS AFTERNOON. BUT
FIRST OFF...LIGHT RAIN/DRIZZLE IN EAST CENTRAL ILLINOIS AND INTO NW
INDY IS ASSOCIATED WITH THE SLIGHTLY BETTER ISENTROPIC LIFT/MOISTURE
ADVECTION. THIS WILL DRIFT OFF TO THE EAST THIS MORNING AND WILL
GRAZE OUR SE COUNTIES. MEANWHILE A SECOND AREA OF LIGHT RAIN
CONTINUES OVER NORTHWEST/NORTH CENTRAL ILLINOIS CLOSER TO THE NORTHWARD
MOVING LOW AND EASTWARD ADVANCING COLD FRONT. MUCH OF OUR AREA FINDS
ITSELF IN AN AREA OF WEAKER ISENTROPIC LIFT AND A BIT REMOVED FROM
THE FRONTAL INFLUENCE. THEREFORE...EXPECT SCATTERED LIGHT
RAIN/DRIZZLE IN BETWEEN THAT SHOULD BE LESS ORGANIZED THAN THESE TWO
AREAS.
THE SURFACE LOW IN IOWA CONTINUES TO DEEPEN AND PUSH NE TO NORTHERN
LAKE MICHIGAN THIS MORNING. THE BETTER UPPER DYNAMICS WITH THE
FRONT ARE WITH THE SHORTWAVE MOVING THROUGH IOWA...AND THIS HEADS
NORTHWEST OF OUR AREA TODAY AS WELL. ENOUGH FRONTAL CONVERGENCE
EXISTS TO CARRY A LOW POP RAIN MENTION THROUGH THE MORNING THOUGH
MANY AREAS STAY DRY. THE BETTER MID LEVEL FORCING/FRONTOGENESIS
ARRIVES WITH THE FRONT THIS AFTERNOON BUT MOISTURE IS
LACKING...THEREFORE EXPECT A LARGELY DRY AFTERNOON EXCEPT IN NW
INDIANA AND EASTERN PORTIONS OF ILLINOIS. WITH A STRENGTHENING
UPPER JET OVERHEAD...EXPECT BREEZY SOUTHWEST WINDS AHEAD OF THE
FRONT...THEN GUSTY WEST WINDS BEHIND IT. AFTER A PLEASANT WARM UP
THE LAST FEW DAYS...THIS FRONT DOES HAVE SOME KICK TO IT...AND
WHILE THE COLD AIR DOES NOT NECESSARILY COME SCREAMING IN...DO
EXPECT A RETURN TO REALITY AND MORE SEASONAL CONDITIONS.
THE COLD FRONT WILL BE THROUGH TONIGHT. ANY LINGERING PRECIP IN OUR
FAR SE COUNTIES OF NW INDIANA MAY SEE A LIGHT RAIN/SNOW MIX BEFORE
PRECIP ENDS. OTHERWISE HIGH PRESSURE NOSES IN FROM THE WEST BRINGING
GRADUAL CLEARING OVERNIGHT. READINGS OVERNIGHT DROP INTO THE 20S
TO AROUND 30. SUNDAY LOOKS TO BE GENERALLY SUNNY BUT SEASONALLY
COLD AS THE MAIN UPPER LOW PASSES THROUGH SOUTHERN CANADA.
KMD
&&
.LONG TERM...
245 AM CST
SUNDAY NIGHT THROUGH FRIDAY...
STRONGER CANADIAN HIGH PRESSURE...WILL BE KNOCKING AT OUR DOOR ON
SUNDAY NIGHT...AND WILL SEND A WEAK BACK DOOR COLD FRONT DOWN THE
LAKE. THE LEADING EDGE OF THIS SECONDARY SURGE OF COLD AIR WILL
TRIGGER A SIGNIFICANTLY COLDER STRETCH OF WEATHER TO KICK OFF THE
LAST FEW DAYS OF 2014. THERE MAY BE SOME WEAK LAKE EFFECT SNOW
SHOWERS GETTING INTO NE ILLINOIS...OTHERWISE INCREASING CLOUDS AND
COLDER. THEN AS THE TRULY ARCTIC AIR SPILLS IN MONDAY NIGHT...WE MAY
SEE SOME SNOW SHOWERS ALONG THE BAROCLINIC ZONE. MOISTURE IS NOT
IMPRESSIVE WITH THE FRONT...BUT THE COMBINED NE FLOW OFF THE LAKE
WITH MORE SIGNIFICANT INVERSION HEIGHTS AND MUCH COLDER AIR MAY
ALLOW FOR LAKE ENHANCEMENT AND SOME BETTER ACCUMULATION POTENTIAL.
THEN THE CHILL ENSUES FOR SEVERAL DAYS OF HIGHS ON EITHER SIDE OF 20
AND LOWS IN THE SINGLE DIGITS AND TEENS AS WE REMAIN IN NW FLOW. THE
UPSIDE...LIKELY SOME MORE SUN TO ENJOY TO END THE YEAR...AS ANY
SHORTWAVE ENERGY ROTATING THROUGH FROM THE CANADIAN VORTEX WILL
EITHER REMAIN NORTH OR GENERALLY BE WEAK AS THE ONE THAT COMES
THROUGH TUESDAY NIGHT. SOME MODIFICATION TO THE COLD AIR MASS
ARRIVES ON NEW YEARS DAY AND MORE SO FRIDAY AS WE RETURN TO
SOUTHERLY FLOW. AS THIS OCCURS...WILL HAVE TO WATCH IF LOW
PRESSURE THAT CLOSES OFF OVER CALIFORNIA EARLIER IN THE WEEK
PHASES WITH THE NORTHERN STREAM LOW OR REMAINS FARTHER SOUTH AS
THIS WILL HAVE IMPLICATIONS FOR ANY PRECIPITATION CHANCES TOWARD
WEEKS END.
KMD
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 12Z...
* IFR CIGS LIFT SLIGHTS TO MVFR TODAY AND POTENTIALLY LINGER
TONIGHT
* BRIEF SHRA ALONG THE FRONT LATE THIS MORNING
* STRONG/GUSTY WEST WINDS LATE THIS MORNING THROUGH THIS AFTERNOON
IZZI
//DISCUSSION...UPDATED 12Z...
COLD FRONT WILL SWEEP ACROSS THE TERMINALS MID-LATE MORNING
PROBABLY ACCOMPANIED BY A BAND OF SHRA ALONG THE FRONT AND QUICKLY
FOLLOWED BY STRONG/GUSTY WEST WINDS. COULD BE A BRIEF PERIOD OF
GUSTS AROUND 30KT BEFORE PREVAILING GUSTS TEND TO SETTLE MORE IN
THE MID-UPPER 20 KNOT RANGE. IFR CIGS THIS MORNING COULD LIFT
SLIGHTLY TO LOW END MVFR PRIOR TO THE FRONT MOVING THROUGH BUT
LIKELY LIFT TO MVFR IN THE WAKE OF THE FRONT. MVFR CIGS WILL
PROBABLY LINGER INTO AT LEAST THIS EVENING BUT COULD POTENTIALLY
CLEAR OUT LATER TONIGHT...BUT CONFIDENCE IN LOW IN CLEARING TIME
SO HELD ON TO MVFR CIGS FOR NOW.
IZZI
//ORD AND MDW CONFIDENCE...UPDATED 12Z...
* MEDIUM CONFIDENCE IN CIGS TODAY...LOW CONFIDENCE TONIGHT
* MEDIUM CONFIDENCE IN SHOWERS
* HIGH CONFIDENCE IN WINDS
IZZI
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT...VFR.
MONDAY...CHANCE OF -SN OR FLURRIES...ESPECIALLY AT NIGHT. MVFR
CIGS LIKELY.
TUESDAY THROUGH FRIDAY...PREDOMINANTLY VFR.
IZZI
&&
.MARINE...
158 AM CST
LOW OVER EASTERN IOWA WILL QUICKLY DEEPEN THROUGH THIS EVENING
AS IT TRACKS NORTHEAST ACROSS NORTHERN LAKE MICHIGAN AND
EVENTUALLY OFF INTO QUEBEC. DUE TO THE BRIEF BUT RAPID DEEPENING
AND COLD AIR ADVECTION THIS AFTERNOON THERE COULD BE A VERY BRIEF
WINDOW OF GALES BEHIND THE FRONT FOR AN HOUR OR TWO OVER SOUTHERN
PORTIONS OF THE LAKE. DURATION LOOKS TO BE TOO SHORT FOR GALE
WARNING THOUGH SO NO HEADLINE PLANNED FOR OPEN WATERS. WINDS/WAVES
LOOK TO RAPIDLY SUBSIDE TONIGHT INTO MONDAY BEFORE AN ARCTIC FRONT
BEGINS WORKING SOUTH DOWN THE LAKE MONDAY NIGHT INTO TUESDAY.
TIGHT GRADIENT BEHIND THE FRONT ALONG WITH VERY COLD AIR AND
UNSTABLE CONDITIONS SHOULD ALLOW FOR STRONG NORTHERLIES TO
DEVELOP...POSSIBLY TO NEAR GALE FORCE BEHIND THE FRONT. THAT
SHOULD MARK THE START OF AN ACTIVE PERIOD ON THE LAKE WITH LOW
PRESSURE TRACKING ACROSS CANADA MIDWEEK DRAGGING A FRONT ACROSS
THE LAKE AND TIGHTENING THE PRESSURE GRADIENT AND PROBABLY LEADING
TO A PERIOD OF WESTERLY GALES WEDNESDAY/EARLY THURSDAY TIME FRAME.
IZZI
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ744-LMZ745...10 AM SATURDAY TO 4 AM
SUNDAY.
SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743...10 AM
SATURDAY TO 10 PM SATURDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
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WWW.YOUTUBE.COM/NWSCHICAGO
[top]
Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
541 AM CST Sat Dec 27 2014
.SHORT TERM...(Today)
ISSUED AT 324 AM CST SAT DEC 27 2014
08z/2am surface analysis shows 1013mb low just north of KMLI, with
frontal boundary extending southwestward into Texas. Airmass ahead
of the front was initially quite dry as evidenced by the 00z KILX
upper air sounding: however, shallow low-level moisture has been on
the increase throughout the night. Surface dewpoints have reached
the middle 40s across central Illinois, while a plume of 50s
dewpoints is noted further upstream pushing into Arkansas. LAPS
soundings show this increasing moisture, with most local profiles
now saturated below 700mb. As low pressure tracks further
northeastward into Wisconsin, it will pull the cold front into the
area later this morning, then to the Indiana border by mid to late
afternoon. Continued moisture pooling along/ahead of the front
will result in increasingly deep moisture profiles, particularly
across the E/SE CWA this afternoon. HRRR suggests only scattered
light showers across much of the area this morning, then shows
more widespread precipitation developing along/east of I-57 this
afternoon. Think this solution makes sense as front gradually taps
into increasing amounts of Gulf moisture as it moves further east.
As a result, will carry chance PoPs across the western half of the
CWA throughout the day, with chance PoPs increasing to likely
across the E/SE this afternoon. With cold front passing through
the area, high temperatures will be achieved this morning,
followed by brisk westerly winds and falling temperatures later in
the day. Due to very mild current temps, have generally gone 2-4
degrees above MAV guidance numbers. End result will be highs in
the upper 40s and lower 50s, with temps dropping into the 30s
along/west of I-55 during the afternoon.
&&
.LONG TERM...(Tonight through Friday)
ISSUED AT 324 AM CST SAT DEC 27 2014
Cold front will slowly push eastward into the Ohio River Valley
tonight, with clouds and showers lingering across the E/SE through
at least the evening hours. NAM is fastest with the departure of
the precip, while GFS tends to keep it around through the entire
night. Based on slow forward movement of the front, have trended
toward the slower GFS. As a result, will maintain low chance PoPs
along/south of I-70 through the overnight hours. As temperatures
slowly fall into the lower to middle 30s across this area, any
lingering rain showers may mix with or change to light snow late.
Further northwest, skies will clear across the Illinois River
Valley, allowing lows to bottom out in the lower to middle 20s.
Sunshine and seasonably cool temps in the 30s will prevail Sunday
into Monday, before a surge of cold air arrives next week. Models
have been consistently showing strong 1050mb high building southward
out of western Canada into the central CONUS by Tuesday/Wednesday.
Weak synoptic lift along the leading edge of the cold air may be
enough to trigger a few flurries across the area Monday night, but
the main story will be the colder temps. High temps will remain in
the 20s Tuesday/Wednesday, while overnight lows dip into the single
digits and teens. After that, Canadian high pressure will gradually
slide east of the region, allowing a southern stream system to
approach by the end of the week. Model solutions vary with this
feature, so forecast confidence remains low at this point. ECMWF
aggressively brings precip northward into south-central Illinois as
early as Thursday night, while the GFS is about 12-18 hours
slower. Meanwhile, the GEM suggests the system may remain largely
southeast of the area across the Ohio River Valley. Given the
uncertainties, have opted to go with a dry forecast Thursday night,
and to slow precip onset on Friday. Have trimmed Friday PoPs to
just slight chance, with higher precip chances arriving Friday night
into Saturday. Think slower/colder is the way to go, especially
given the Canadian airmass that will initially be in place. End
result will be a chance of snow or a rain/snow mix mainly Friday
night into Saturday.
&&
.AVIATION...(For the 12Z TAFS through 12Z Sunday morning)
ISSUED AT 533 AM CST SAT DEC 27 2014
Widespread IFR conditions (mainly CIGS) can be expected across the
central Illinois terminals to start the 12Z TAF valid time. These
low CIGS are occurring in an unseasonably warm/moist airmass ahead
of an approaching cold front. CIGS should quickly rise to MVFR
with the passage of a cold front later this morning or early this
afternoon. The passage of this front will have winds swinging
around from the southwest to the west. Expect low clouds to
scatter out this evening as drier air filters into the region
behind the front. This drier air will also be accompanied by a
wind shift to the northwest.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Barnes
LONG TERM...Barnes
AVIATION...Bak
AREA FORECAST DISCUSSION
NWS JACKSON KY
1040 AM EST SAT DEC 27 2014
.UPDATE...
ISSUED AT 1040 AM EST SAT DEC 27 2014
THE SPRINKLE AND SHOWER ACTIVITY IS BEGINNING TO WIND DOWN AS IT
SHIFTS TO THE NORTHEAST THROUGH THE AREA. IT SEEMS THAT THE CURRENT
FORECAST HAS THE PRECIP HANDLED FOR NOW. WILL HAVE TO ISSUE A NEW ZFP
WHEN THE PRECIP EXITS THE AREA AS THERE WILL BE MORNING WORDING THAT
NEEDS ADDRESSED ANYWAY. DESPITE THIS LIGHT ACTIVITY...THE MORNING
INTO THE NOON PERIOD LOOKS TO BE QUIET. TRENDS ARE STILL ON TRACK FOR
THE LARGE SWATH OF PRECIP TO ARRIVE THIS EVENING. FOR NOW...JUST SENT
OUT A NEW SET OF GRIDS WITH THE LATEST OBS AND WILL CONTINUE TO
ADDRESS THE LIGHT SPRINKLES WITH A GRAPHICAL NOW CAST.
UPDATE ISSUED AT 730 AM EST SAT DEC 27 2014
BAND OF RAIN SHOWERS HAS BEEN MOVING ACROSS THE COMMONWEALTH EARLY
THIS MORNING. HRRR HAS BEEN CONSISTENT WITH THE IDEA OF THIS BAND
WEAKENING AND DISSIPATING AS IT MOVES EASTWARD. HOWEVER...THE HRRR
HAS TRENDED SLOWER WITH THE OVERALL DISSIPATION WITH EACH NEW RUN.
MOST RECENT RUN INDICATES THAT SOME OF THE SHOWER ACTIVITY COULD
HOLD TOGETHER LONG ENOUGH TO PROVIDE US WITH SOME RAIN...MAINLY
ACROSS OUR BLUE GRASS COUNTIES. THIS TREND SEEMS TO BE SUPPORTED BY
THE FACT THAT THE BAND HAS BEEN FAIRLY PERSISTENT THUS FAR. THEREFORE
INTRODUCED POPS ACROSS OUR NORTH FOR THE EARLY AND MID MORNING TIME
FRAME WHILE MAINTAINING A GRADUAL WEAKENING TREND. ALSO INCLUDED A
SWATH OF SPRINKLES AHEAD OF THIS INITIAL BAND FOR SOME AREAS THAT
ARE NOT EXPECTED TO SEE ACTUAL SHOWERS. OTHERWISE FORECAST APPEARS ON
TRACK.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 337 AM EST SAT DEC 27 2014
MODELS ARE IN GOOD AGREEMENT THROUGH THE SHORT TERM...THOUGH THEY
WERE LATE IN PICKING UP ON POTENTIAL SHOWER ACTIVITY CURRENTLY MOVING
EAST OF OUR AREA. HRRR IS PICKING UP ON ADDITIONAL SHOWER ACTIVITY
FAR TO OUR WEST...OVER THE WESTERN END OF THE COMMONWEALTH AND DOES
BRING THAT EASTWARD TOWARDS OUR AREA. BUT ACTIVITY SUPPOSEDLY WEAKENS
AND DISSIPATES BY THE TIME IT REACHES OUR CWA AROUND MID MORNING.
OTHER OPERATIONAL MODELS TEND TO SUPPORT THIS SCENARIO THOUGH WILL
HAVE TO WATCH THIS CAREFULLY THROUGH THE MORNING IN CASE MODELS WIND
UP HANDLING THIS POORLY AS WELL AND POPS NEED TO BE RAMPED UP MORE
QUICKLY THROUGH THE DAY.
MID/UPPER LEVEL RIDGE...CENTERED OVER CUBA IS RETREATING EASTWARD
WITH APPROACH OF SHORT WAVE ENERGY AND TROUGH LIFTING OUT OF THE
WESTERN GREAT BASIN...SOUTHWEST CONUS. AT THE SFC...HIGH PRESSURE
CENTERED OVER THE CENTRAL ATLANTIC COASTAL REGION IS ALSO BEGINNING
TO RETREAT EASTWARD. CONTINUED MOVEMENT OF MID/UPPER LEVEL TROUGH
OUT OF THE WESTERN CONUS WILL INDUCE A SERIES OF SFC LOWS...THE FIRST
DEVELOPING OVER THE EASTERN PLAINS AND MOVING THROUGH THE GREAT
LAKES BY LATE TODAY. THIS FIRST LOW WILL DRAG A SFC COLD FRONTAL
BOUNDARY INTO THE OHIO VALLEY TONIGHT...REACHING OUR CWA BY SUNDAY
MORNING. A SECOND LOW WILL DEVELOP MUCH FURTHER SOUTH OVER THE
SOUTHERN MISSISSIPPI VALLEY REGION AND TRACK NORTHEAST ALONG THE
FRONT AS THE SFC BOUNDARY PUSHES ACROSS THE APPALACHIANS SUNDAY
MORNING. THIS WILL KEEP OUR WEATHER WET THROUGH TO THE END OF THE
SHORT TERM.
FOR SENSIBLE WEATHER...WEAK IMPULSE RESPONSIBLE FOR SPRINKLES AND
VERY ISOLATED SHOWER ACTIVITY OVER OUR AREA EARLY THIS MORNING IS
EXITING TO OUR EAST...WITH CORRESPONDING ACTIVITY EXITING AS WELL.
MID AND HIGH LEVEL CLOUDS WILL CONTINUE TO THICKEN AND LOWER WITH
TIME...THOUGH WE COULD SEE A FEW BREAKS AT TIMES THROUGH THE DAY.
COULD SEE SOME ADDITIONAL SPRINKLES ACROSS PORTIONS OF OUR AREA BY
MID MORNING TO NOON AS THE SECOND AREA OF ACTIVITY TO OUR FAR WEST
WEAKENS WHILE MOVING EASTWARD. OUR MAIN EVENT...RAIN ASSOCIATED WITH
THE APPROACHING COLD FRONTAL SYSTEM WILL BEGIN TO OVERSPREAD OUR AREA
FROM THE WEST LATE THIS AFTERNOON. RAIN WILL INCREASE THROUGH THE
OVERNIGHT AND LINGER THROUGH THE DAY SUNDAY AS THE AFOREMENTIONED
SECOND WAVE OF LOW PRESSURE RIDES UP INTO THE SOUTHERN APPALACHIANS.
INCREASED POPS FOR TONIGHT AND SUNDAY FOLLOWING THE LEAD OF GUIDANCE.
TEMPERATURES CONTINUE TO MODERATE WITH A RELATIVELY LIMITED DIURNAL
RANGE OVER THE NEXT 18 TO 24 HOURS DUE TO INCREASED CLOUD COVER. ALSO
PREFERRED TO GO WITH A NON DIURNAL TEMP TREND THROUGH THE DAY SUNDAY
AS COLDER AIR FILTERS IN BEHIND THE SFC COLD FRONT.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 337 AM EST SAT DEC 27 2014
FRONTAL BOUNDARY AND WAVES OF LOW PRESSURE WILL SLOWLY PUSH EAST OF
THE CWA MOVING INTO THE LONG TERM PERIOD. SLOWLY LESSEN POPS
OVERNIGHT SUNDAY INTO MONDAY AS BETTER LIFT MOVES EAST OF THE REGION.
AFTER THIS THERE IS A UPPER LEVEL DISTURBANCE THAT MOVES ACROSS THE
REGION GOING INTO TUESDAY THIS WILL BRING SOME CLOUD COVER TO THE
REGION. OTHER THAN THAT NOT EXPECTING MUCH IN THE WAY OF PRECIP AS
HIGH PRESSURE CONTINUES BUILDS EAST WEDNESDAY WITH SKIES CLEARING OUT
THROUGH THE DAY. COOLER AIR WILL FILTER INTO THE REGION GIVING WAY TO
HIGHS IN THE LOW TO MID 30S FOR HIGHS ON WEDNESDAY. CONTINUED
CLEARING SKIES AND BUILDING HIGH PRESSURE WILL GIVE WAY TO GOOD
RADIATIONAL COOLING WEDNESDAY NIGHT WITH LOWS IN THE UPPER TEENS TO
LOWER 20S ACROSS THE REGION. MORE UNCERTAINTY IN THE MODELS EXIST AS
WE MOVE INTO THE LONGER RANGE PORTION OF THE LONG TERM. HIGH PRESSURE
IS EXPECTED TO SLOWLY MOVE EAST AS WE MOVE INTO THURSDAY. RIGHT NOW
THURSDAY LOOKS DRY...HOWEVER A LOW PRESSURE SYSTEM IS EXPECT TO
DEVELOP ACROSS THE SOUTHERN PLAINS THURSDAY/FRIDAY AS UPPER LEVEL LOW
EJECTS OUT OF THE FOUR CORNERS REGION. MOISTURE WILL SLOWLY SPREAD
NORTH AND EAST TOWARD THE OHIO VALLEY AS WE MOVE INTO FRIDAY. TIMING
ON THE PRECIP DIFFER AT THIS POINT WITH ECMWF MOST PROGRESSIVE. GIVEN
THE UNCERTAINTY DID STICK REASONABLY CLOSE TO THE MODEL BLEND AND
TRYING TO KEEP SOME CONSISTENCY/COLLABORATION. THIS DOES GIVE WAY TO
SLIGHT POPS THURSDAY NIGHT AND CHANCE POPS FRIDAY. GIVEN COOLER TEMPS
ONSET OF POPS WOULD BE A SNOW OR RAIN/SNOW MIX THURSDAY NIGHT INTO
EARLY FRIDAY. HOWEVER RIGHT NOW CONFIDENCE REMAINS LOW GIVEN MODEL
DIVERGENCE DURING THIS PERIOD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 730 AM EST SAT DEC 27 2014
SHOWERS ASSOCIATED WITH AN APPROACHING COLD FRONTAL SYSTEM WILL
DEVELOP ACROSS THE REGION TODAY...DROPPING FLIGHT CONDITIONS INTO
MVFR TERRITORY FROM WEST TO EAST LATE THIS AFTERNOON AND THIS
EVENING. CONDITIONS WORSEN OVERNIGHT AS RAIN PICKS UP AND LINGERS
THROUGH THE REMAINDER OF THE FORECAST. WINDS WILL RUN LESS THAN 10
KTS THROUGH THE PERIOD...GENERALLY FROM THE SOUTH/SOUTHWEST.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...SHALLENBERGER
SHORT TERM...RAY
LONG TERM...DJ
AVIATION...RAY
AREA FORECAST DISCUSSION...CORRECTED
NWS JACKSON KY
744 AM EST SAT DEC 27 2014
.UPDATE...
ISSUED AT 730 AM EST SAT DEC 27 2014
BAND OF RAIN SHOWERS HAS BEEN MOVING ACROSS THE COMMONWEALTH EARLY
THIS MORNING. HRRR HAS BEEN CONSISTENT WITH THE IDEA OF THIS BAND
WEAKENING AND DISSIPATING AS IT MOVES EASTWARD. HOWEVER...THE HRRR
HAS TRENDED SLOWER WITH THE OVERALL DISSIPATION WITH EACH NEW RUN.
MOST RECENT RUN INDICATES THAT SOME OF THE SHOWER ACTIVITY COULD
HOLD TOGETHER LONG ENOUGH TO PROVIDE US WITH SOME RAIN...MAINLY
ACROSS OUR BLUE GRASS COUNTIES. THIS TREND SEEMS TO BE SUPPORTED BY
THE FACT THAT THE BAND HAS BEEN FAIRLY PERSISTENT THUS FAR. THEREFORE
INTRODUCED POPS ACROSS OUR NORTH FOR THE EARLY AND MID MORNING TIME
FRAME WHILE MAINTAINING A GRADUAL WEAKENING TREND. ALSO INCLUDED A
SWATH OF SPRINKLES AHEAD OF THIS INITIAL BAND FOR SOME AREAS THAT
ARE NOT EXPECTED TO SEE ACTUAL SHOWERS. OTHERWISE FORECAST APPEARS ON
TRACK.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 337 AM EST SAT DEC 27 2014
MODELS ARE IN GOOD AGREEMENT THROUGH THE SHORT TERM...THOUGH THEY
WERE LATE IN PICKING UP ON POTENTIAL SHOWER ACTIVITY CURRENTLY MOVING
EAST OF OUR AREA. HRRR IS PICKING UP ON ADDITIONAL SHOWER ACTIVITY
FAR TO OUR WEST...OVER THE WESTERN END OF THE COMMONWEALTH AND DOES
BRING THAT EASTWARD TOWARDS OUR AREA. BUT ACTIVITY SUPPOSEDLY WEAKENS
AND DISSIPATES BY THE TIME IT REACHES OUR CWA AROUND MID MORNING.
OTHER OPERATIONAL MODELS TEND TO SUPPORT THIS SCENARIO THOUGH WILL
HAVE TO WATCH THIS CAREFULLY THROUGH THE MORNING IN CASE MODELS WIND
UP HANDLING THIS POORLY AS WELL AND POPS NEED TO BE RAMPED UP MORE
QUICKLY THROUGH THE DAY.
MID/UPPER LEVEL RIDGE...CENTERED OVER CUBA IS RETREATING EASTWARD
WITH APPROACH OF SHORT WAVE ENERGY AND TROUGH LIFTING OUT OF THE
WESTERN GREAT BASIN...SOUTHWEST CONUS. AT THE SFC...HIGH PRESSURE
CENTERED OVER THE CENTRAL ATLANTIC COASTAL REGION IS ALSO BEGINNING
TO RETREAT EASTWARD. CONTINUED MOVEMENT OF MID/UPPER LEVEL TROUGH
OUT OF THE WESTERN CONUS WILL INDUCE A SERIES OF SFC LOWS...THE FIRST
DEVELOPING OVER THE EASTERN PLAINS AND MOVING THROUGH THE GREAT
LAKES BY LATE TODAY. THIS FIRST LOW WILL DRAG A SFC COLD FRONTAL
BOUNDARY INTO THE OHIO VALLEY TONIGHT...REACHING OUR CWA BY SUNDAY
MORNING. A SECOND LOW WILL DEVELOP MUCH FURTHER SOUTH OVER THE
SOUTHERN MISSISSIPPI VALLEY REGION AND TRACK NORTHEAST ALONG THE
FRONT AS THE SFC BOUNDARY PUSHES ACROSS THE APPALACHIANS SUNDAY
MORNING. THIS WILL KEEP OUR WEATHER WET THROUGH TO THE END OF THE
SHORT TERM.
FOR SENSIBLE WEATHER...WEAK IMPULSE RESPONSIBLE FOR SPRINKLES AND
VERY ISOLATED SHOWER ACTIVITY OVER OUR AREA EARLY THIS MORNING IS
EXITING TO OUR EAST...WITH CORRESPONDING ACTIVITY EXITING AS WELL.
MID AND HIGH LEVEL CLOUDS WILL CONTINUE TO THICKEN AND LOWER WITH
TIME...THOUGH WE COULD SEE A FEW BREAKS AT TIMES THROUGH THE DAY.
COULD SEE SOME ADDITIONAL SPRINKLES ACROSS PORTIONS OF OUR AREA BY
MID MORNING TO NOON AS THE SECOND AREA OF ACTIVITY TO OUR FAR WEST
WEAKENS WHILE MOVING EASTWARD. OUR MAIN EVENT...RAIN ASSOCIATED WITH
THE APPROACHING COLD FRONTAL SYSTEM WILL BEGIN TO OVERSPREAD OUR AREA
FROM THE WEST LATE THIS AFTERNOON. RAIN WILL INCREASE THROUGH THE
OVERNIGHT AND LINGER THROUGH THE DAY SUNDAY AS THE AFOREMENTIONED
SECOND WAVE OF LOW PRESSURE RIDES UP INTO THE SOUTHERN APPALACHIANS.
INCREASED POPS FOR TONIGHT AND SUNDAY FOLLOWING THE LEAD OF GUIDANCE.
TEMPERATURES CONTINUE TO MODERATE WITH A RELATIVELY LIMITED DIURNAL
RANGE OVER THE NEXT 18 TO 24 HOURS DUE TO INCREASED CLOUD COVER. ALSO
PREFERRED TO GO WITH A NON DIURNAL TEMP TREND THROUGH THE DAY SUNDAY
AS COLDER AIR FILTERS IN BEHIND THE SFC COLD FRONT.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 337 AM EST SAT DEC 27 2014
FRONTAL BOUNDARY AND WAVES OF LOW PRESSURE WILL SLOWLY PUSH EAST OF
THE CWA MOVING INTO THE LONG TERM PERIOD. SLOWLY LESSEN POPS
OVERNIGHT SUNDAY INTO MONDAY AS BETTER LIFT MOVES EAST OF THE REGION.
AFTER THIS THERE IS A UPPER LEVEL DISTURBANCE THAT MOVES ACROSS THE
REGION GOING INTO TUESDAY THIS WILL BRING SOME CLOUD COVER TO THE
REGION. OTHER THAN THAT NOT EXPECTING MUCH IN THE WAY OF PRECIP AS
HIGH PRESSURE CONTINUES BUILDS EAST WEDNESDAY WITH SKIES CLEARING OUT
THROUGH THE DAY. COOLER AIR WILL FILTER INTO THE REGION GIVING WAY TO
HIGHS IN THE LOW TO MID 30S FOR HIGHS ON WEDNESDAY. CONTINUED
CLEARING SKIES AND BUILDING HIGH PRESSURE WILL GIVE WAY TO GOOD
RADIATIONAL COOLING WEDNESDAY NIGHT WITH LOWS IN THE UPPER TEENS TO
LOWER 20S ACROSS THE REGION. MORE UNCERTAINTY IN THE MODELS EXIST AS
WE MOVE INTO THE LONGER RANGE PORTION OF THE LONG TERM. HIGH PRESSURE
IS EXPECTED TO SLOWLY MOVE EAST AS WE MOVE INTO THURSDAY. RIGHT NOW
THURSDAY LOOKS DRY...HOWEVER A LOW PRESSURE SYSTEM IS EXPECT TO
DEVELOP ACROSS THE SOUTHERN PLAINS THURSDAY/FRIDAY AS UPPER LEVEL LOW
EJECTS OUT OF THE FOUR CORNERS REGION. MOISTURE WILL SLOWLY SPREAD
NORTH AND EAST TOWARD THE OHIO VALLEY AS WE MOVE INTO FRIDAY. TIMING
ON THE PRECIP DIFFER AT THIS POINT WITH ECMWF MOST PROGRESSIVE. GIVEN
THE UNCERTAINTY DID STICK REASONABLY CLOSE TO THE MODEL BLEND AND
TRYING TO KEEP SOME CONSISTENCY/COLLABORATION. THIS DOES GIVE WAY TO
SLIGHT POPS THURSDAY NIGHT AND CHANCE POPS FRIDAY. GIVEN COOLER TEMPS
ONSET OF POPS WOULD BE A SNOW OR RAIN/SNOW MIX THURSDAY NIGHT INTO
EARLY FRIDAY. HOWEVER RIGHT NOW CONFIDENCE REMAINS LOW GIVEN MODEL
DIVERGENCE DURING THIS PERIOD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 730 AM EST SAT DEC 27 2014
SHOWERS ASSOCIATED WITH AN APPROACHING COLD FRONTAL SYSTEM WILL
DEVELOP ACROSS THE REGION TODAY...DROPPING FLIGHT CONDITIONS INTO
MVFR TERRITORY FROM WEST TO EAST LATE THIS AFTERNOON AND THIS
EVENING. CONDITIONS WORSEN OVERNIGHT AS RAIN PICKS UP AND LINGERS
THROUGH THE REMAINDER OF THE FORECAST. WINDS WILL RUN LESS THAN 10
KTS THROUGH THE PERIOD...GENERALLY FROM THE SOUTH/SOUTHWEST.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
UPDATE...RAY
SHORT TERM...RAY
LONG TERM...DJ
AVIATION...RAY
AREA FORECAST DISCUSSION
NWS JACKSON KY
730 AM EST SAT DEC 27 2014
.UPDATE...
ISSUED AT 730 AM EST SAT DEC 27 2014
BAND OF RAIN SHOWERS HAS BEEN MOVING ACROSS THE COMMONWEALTH EARLY
THIS MORNING. HRRR HAS BEEN CONSISTENT WITH THE IDEA OF THIS BAND
WEAKENING AND DISSIPATING AS IT MOVES EASTWARD. HOWEVER...RECENT RUNS
HAS SHOWN A SLOWER TREND OVERALL WITH INDICATIONS THAT SOME OF THE
SHOWER ACTIVITY COULD HOLD TOGETHER LONG ENOUGH TO PROVIDE US WITH
SOME RAIN...MAINLY ACROSS OUR BLUE GRASS COUNTIES. THIS TREND SEEMS
TO BE SUPPORTED BY THE FACT THAT THE BAND HAS BEEN FAIRLY PERSISTENT
THUS FAR. THEREFORE INTRODUCED POPS ACROSS OUR NORTH FOR THE MID
MORNING TIME FRAME WHILE MAINTAINING A GRADUAL WEAKENING TREND. ALSO
INCLUDED A WIDER SWATH OF SPRINKLES FOR SOME AREAS THAT MAY NOT SEE
ANY RAIN THIS MORNING. OTHERWISE FORECAST APPEARS ON TRACK.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 337 AM EST SAT DEC 27 2014
MODELS ARE IN GOOD AGREEMENT THROUGH THE SHORT TERM...THOUGH THEY
WERE LATE IN PICKING UP ON POTENTIAL SHOWER ACTIVITY CURRENTLY MOVING
EAST OF OUR AREA. HRRR IS PICKING UP ON ADDITIONAL SHOWER ACTIVITY
FAR TO OUR WEST...OVER THE WESTERN END OF THE COMMONWEALTH AND DOES
BRING THAT EASTWARD TOWARDS OUR AREA. BUT ACTIVITY SUPPOSEDLY WEAKENS
AND DISSIPATES BY THE TIME IT REACHES OUR CWA AROUND MID MORNING.
OTHER OPERATIONAL MODELS TEND TO SUPPORT THIS SCENARIO THOUGH WILL
HAVE TO WATCH THIS CAREFULLY THROUGH THE MORNING IN CASE MODELS WIND
UP HANDLING THIS POORLY AS WELL AND POPS NEED TO BE RAMPED UP MORE
QUICKLY THROUGH THE DAY.
MID/UPPER LEVEL RIDGE...CENTERED OVER CUBA IS RETREATING EASTWARD
WITH APPROACH OF SHORT WAVE ENERGY AND TROUGH LIFTING OUT OF THE
WESTERN GREAT BASIN...SOUTHWEST CONUS. AT THE SFC...HIGH PRESSURE
CENTERED OVER THE CENTRAL ATLANTIC COASTAL REGION IS ALSO BEGINNING
TO RETREAT EASTWARD. CONTINUED MOVEMENT OF MID/UPPER LEVEL TROUGH
OUT OF THE WESTERN CONUS WILL INDUCE A SERIES OF SFC LOWS...THE FIRST
DEVELOPING OVER THE EASTERN PLAINS AND MOVING THROUGH THE GREAT
LAKES BY LATE TODAY. THIS FIRST LOW WILL DRAG A SFC COLD FRONTAL
BOUNDARY INTO THE OHIO VALLEY TONIGHT...REACHING OUR CWA BY SUNDAY
MORNING. A SECOND LOW WILL DEVELOP MUCH FURTHER SOUTH OVER THE
SOUTHERN MISSISSIPPI VALLEY REGION AND TRACK NORTHEAST ALONG THE
FRONT AS THE SFC BOUNDARY PUSHES ACROSS THE APPALACHIANS SUNDAY
MORNING. THIS WILL KEEP OUR WEATHER WET THROUGH TO THE END OF THE
SHORT TERM.
FOR SENSIBLE WEATHER...WEAK IMPULSE RESPONSIBLE FOR SPRINKLES AND
VERY ISOLATED SHOWER ACTIVITY OVER OUR AREA EARLY THIS MORNING IS
EXITING TO OUR EAST...WITH CORRESPONDING ACTIVITY EXITING AS WELL.
MID AND HIGH LEVEL CLOUDS WILL CONTINUE TO THICKEN AND LOWER WITH
TIME...THOUGH WE COULD SEE A FEW BREAKS AT TIMES THROUGH THE DAY.
COULD SEE SOME ADDITIONAL SPRINKLES ACROSS PORTIONS OF OUR AREA BY
MID MORNING TO NOON AS THE SECOND AREA OF ACTIVITY TO OUR FAR WEST
WEAKENS WHILE MOVING EASTWARD. OUR MAIN EVENT...RAIN ASSOCIATED WITH
THE APPROACHING COLD FRONTAL SYSTEM WILL BEGIN TO OVERSPREAD OUR AREA
FROM THE WEST LATE THIS AFTERNOON. RAIN WILL INCREASE THROUGH THE
OVERNIGHT AND LINGER THROUGH THE DAY SUNDAY AS THE AFOREMENTIONED
SECOND WAVE OF LOW PRESSURE RIDES UP INTO THE SOUTHERN APPALACHIANS.
INCREASED POPS FOR TONIGHT AND SUNDAY FOLLOWING THE LEAD OF GUIDANCE.
TEMPERATURES CONTINUE TO MODERATE WITH A RELATIVELY LIMITED DIURNAL
RANGE OVER THE NEXT 18 TO 24 HOURS DUE TO INCREASED CLOUD COVER. ALSO
PREFERRED TO GO WITH A NON DIURNAL TEMP TREND THROUGH THE DAY SUNDAY
AS COLDER AIR FILTERS IN BEHIND THE SFC COLD FRONT.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 337 AM EST SAT DEC 27 2014
FRONTAL BOUNDARY AND WAVES OF LOW PRESSURE WILL SLOWLY PUSH EAST OF
THE CWA MOVING INTO THE LONG TERM PERIOD. SLOWLY LESSEN POPS
OVERNIGHT SUNDAY INTO MONDAY AS BETTER LIFT MOVES EAST OF THE REGION.
AFTER THIS THERE IS A UPPER LEVEL DISTURBANCE THAT MOVES ACROSS THE
REGION GOING INTO TUESDAY THIS WILL BRING SOME CLOUD COVER TO THE
REGION. OTHER THAN THAT NOT EXPECTING MUCH IN THE WAY OF PRECIP AS
HIGH PRESSURE CONTINUES BUILDS EAST WEDNESDAY WITH SKIES CLEARING OUT
THROUGH THE DAY. COOLER AIR WILL FILTER INTO THE REGION GIVING WAY TO
HIGHS IN THE LOW TO MID 30S FOR HIGHS ON WEDNESDAY. CONTINUED
CLEARING SKIES AND BUILDING HIGH PRESSURE WILL GIVE WAY TO GOOD
RADIATIONAL COOLING WEDNESDAY NIGHT WITH LOWS IN THE UPPER TEENS TO
LOWER 20S ACROSS THE REGION. MORE UNCERTAINTY IN THE MODELS EXIST AS
WE MOVE INTO THE LONGER RANGE PORTION OF THE LONG TERM. HIGH PRESSURE
IS EXPECTED TO SLOWLY MOVE EAST AS WE MOVE INTO THURSDAY. RIGHT NOW
THURSDAY LOOKS DRY...HOWEVER A LOW PRESSURE SYSTEM IS EXPECT TO
DEVELOP ACROSS THE SOUTHERN PLAINS THURSDAY/FRIDAY AS UPPER LEVEL LOW
EJECTS OUT OF THE FOUR CORNERS REGION. MOISTURE WILL SLOWLY SPREAD
NORTH AND EAST TOWARD THE OHIO VALLEY AS WE MOVE INTO FRIDAY. TIMING
ON THE PRECIP DIFFER AT THIS POINT WITH ECMWF MOST PROGRESSIVE. GIVEN
THE UNCERTAINTY DID STICK REASONABLY CLOSE TO THE MODEL BLEND AND
TRYING TO KEEP SOME CONSISTENCY/COLLABORATION. THIS DOES GIVE WAY TO
SLIGHT POPS THURSDAY NIGHT AND CHANCE POPS FRIDAY. GIVEN COOLER TEMPS
ONSET OF POPS WOULD BE A SNOW OR RAIN/SNOW MIX THURSDAY NIGHT INTO
EARLY FRIDAY. HOWEVER RIGHT NOW CONFIDENCE REMAINS LOW GIVEN MODEL
DIVERGENCE DURING THIS PERIOD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 730 AM EST SAT DEC 27 2014
SHOWERS ASSOCIATED WITH AN APPROACHING COLD FRONTAL SYSTEM WILL
DEVELOP ACROSS THE REGION TODAY...DROPPING FLIGHT CONDITIONS INTO
MVFR TERRITORY FROM WEST TO EAST LATE THIS AFTERNOON AND THIS
EVENING. CONDITIONS WORSEN OVERNIGHT AS RAIN PICKS UP AND LINGERS
THROUGH THE REMAINDER OF THE FORECAST. WINDS WILL RUN LESS THAN 10
KTS THROUGH THE PERIOD...GENERALLY FROM THE SOUTH/SOUTHWEST.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
UPDATE...RAY
SHORT TERM...RAY
LONG TERM...DJ
AVIATION...RAY
AREA FORECAST DISCUSSION...UPDATED
NWS MARQUETTE MI
940 AM EST SAT DEC 27 2014
.UPDATE...
ISSUED AT 939 AM EST SAT DEC 27 2014
DIFFICULT HEADLINE DECISION THIS MORNING AS THERE WILL LIKELY BE A
SWATH OF SNOWFALL AMOUNTS RIGHT AROUND OUR 6IN/12HR CRITERIA OVER
CENTRAL UPPER MICHIGAN. BELIEVE THE SNOWFALL AMOUNTS THAT WE HAVE
IN THE FORECAST ARE IN LINE FOR WHAT IS EXPECTED WITH THIS LAST
AREA OF SNOW THAT WILL MOVE THROUGH THIS MORNING. THAT AREA WITH
THE FORECASTED HIGHEST AMOUNTS IS IN LINE WITH THE AREA OF RAPIDLY
COOLING CLOUD TOPS OVER CENTRAL UPPER MICHIGAN AND NORTHEAST
WISCONSIN AND MATCHES THE LATEST QPF AMOUNTS FROM THE RAP/HRRR. ON
THE WESTERN EDGE OF THIS SWATH (IRON/DICKINSON COUNTIES)...THEY HAVE
RECEIVED 2.5-3.5 INCHES OF SNOW THUS FAR OVER 9-10 HOURS AND WILL
RECEIVE ANOTHER 2-3 INCHES OVER THE NEXT 3-4HRS WHICH PUTS THEM ON
THE EDGE OF THE CRITERIA. FARTHER EAST...AMOUNTS HAVE BEEN LOWER AND
IN THE 1-2.5 INCH RANGE...BUT THEY WILL LIKELY SEE THE GREATEST
AMOUNTS OF 3.5-5 INCHES. THIS ALSO PUTS THOSE AREAS RIGHT AROUND THE
6 INCH CRITERIA. FEEL THE MOST CONFIDENT ON AMOUNTS JUST OVER
WARNING CRITERIA FROM NORTHERN DICKINSON THROUGH THE SOUTHEAST HALF
OF MARQUETTE AND WESTERN ALGER COUNTY...BUT NOT SURE IF THE UPGRADE
WITH ANOTHER 3-4HRS OF SNOW LEFT IS WORTH THE HEADLINE CHANGE. IN
ADDITION...THE OVERALL WORDING WILL STAY THE SAME. THUS...WILL
UPDATE THE WSW TO HIGHLIGHT THE HEAVIER SNOW OVER THE NEXT FEW HOURS
AND KEEP THE ADVISORIES AS IS...ESPECIALLY SINCE WEBCAMS SHOW MANY
LOCATIONS EAST OF A MARQUETTE TO IRON MOUNTAIN LINE STILL HAVING
MAINLY WET ROADS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 535 AM EST SAT DEC 27 2014
LATEST WATER VAPOR LOOP AND RUC ANALYSIS SHOWS A VIGOROUS AND
WELL-DEFINED SHORTWAVE LIFTING NE INTO SRN MN AND NW WI WITH
DEVELOPING BAROCLINIC LEAF STRUCTURE/DEFORMATION ZONE. MID-LVL FGEN
ASSOC WITH SHORTWAVE STRETCHING FROM SRN MN AND NW WI INTO THE UPPER
MI HELPING SUPPORT LIGHT TO MODERATE SNOW.
TODAY...MID-LVL FGEN STRETCHING ACROSS THE UPPER MIDWEST TO THE
UPPER GREAT LAKES WILL CONTINUE TO SUPPORT MODERATE SNOW INTO EARLY
AFTERNOON. BROAD SCALE SYNOPTIC ASCENT WILL BE AIDED BY UPPER
DIVERGENCE IN THE LEFT EXIT REGION OF THE 300 MB JET. NEGATIVE EPV
NOTED ON CROSS-SECTIONS WITHIN A REGION OF MID-LVL FRONTOGENESIS
COULD LEAD TO SOME LOCALLY HEAVIER SNOW BANDS AS SFC LOW TRACKS JUST
SE OF AREA THIS MORNING AND THEN ACROSS THE STRAITS EARLY THIS AFTERNOON.
MODEL CONSENSUS QPF ARGUES FOR AREA OF HEAVIER SNOW JUST NW OF LOW
TRACK ALONG AND EAST OF A LINE FROM IRON RIVER THROUGH ISHPEMING
WHERE MODELS SHOW STRONG 285-290K ISENTROPIC ASCENT OVER A SIX-HR
PERIOD WITH 4 G/KG MIXR ADVECTING ACROSS AREA. THIS SWATH OF HEAVIER
SNOW WILL TAPER OFF BY MID AFTERNOON AS MID-LVL FGEN WEAKENS AND
BEGINS TO MOVE NE WITH DEPARTING SFC LOW. MODEL AVG QPF FM .25 INCH
WEST TO NEAR .5 INCH OVER PORTIONS OF THE CENTRAL CWA WITH EXPECTED
SNOW/WATER RATIOS FM 15/1 WEST TO NEAR 12/1 EAST HALF SHOULD YIELD
TOTAL SNOW ACCUMULATION FM 2-5 INCHES WEST TO 3-6 INCHES CENTRAL.
SINCE 6 INCH AMOUNTS SHOULD BE FAIRLY LOCALIZED WILL CONTINUE WITH
WINTER WX ADVISORY HEADLINES AT THIS POINT AND NOT UPGRADE TO
WARNINGS...BUT SITUATION WILL DEFINITELY WARRANT MONITORING THIS
MORNING. ALSO HAVE DECIDED TO INCLUDE ONTONAGON AND SRN HOUGHTON IN
ADVISORIES AS THEY SHOULD BE ON WRN EDGE OF HEAVIER QPF THIS MORNING.
TONIGHT...WITH SYSTEM SNOW OVER BY LATE AFTERNOON FOR EAST...EXPECT
TRANSITION TO PURE LAKE EFFECT SNOW TONIGHT AS 850MB TEMPS FALL FROM
-10 TO -12C IN THE EVENING TO -12 TO -16C BY 12Z SUN UNDER LOW-LEVEL
W TO WNW FLOW. LARGE SCALE DEEP LAYER Q-VECTOR DIVERGENCE WILL
DOMINATE THIS EVENING AND NAM/GFS FCST SOUNDINGS SHOWING INVERSIONS
BASED NEAR 4KFT...ANY DEVELOPING LES WILL BE ON THE LIGHT SIDE OVER
THE KEWEENAW. HOWEVER...LATER TONIGHT THERE IS A POTENTIAL FOR SOME
WEAK ENHANCEMENT AS A SHORTWAVE PASSES ACROSS NRN ONTARIO AND SENDS
A SFC TROF S ACROSS THE UPPER LAKES. GFS/NAM FCST SOUNDINGS SHOW AN
INCREASE IN MOISTURE DEPTH AND LIFTING OF THE INVERSION. THIS
ENHANCEMENT COMBINED WITH FAVORABLE PLACEMENT OF DGZ WITHIN
CONVECTIVE BOUNDARY LAYER AND SHARPENING OF THE WIND
SHIFT/CONVERGENCE AS TROF MOVES THROUGH AREA COULD YIELD MODERATE
SNOW LATE TONIGHT WITH A QUICK 1 TO LOCALLY 3 INCHES OF SNOW IN NRN
ONTONAGON/HOUGHTON COUNTIES WHERE SHARPEST CONVERGENCE IS INDICATED
AND WHERE UPSLOPING WILL FURTHER AID SNOW ACCUMULATIONS.
WENT ON COLDER SIDE OF GUIDANCE FOR MIN TEMPS ESPECIALLY OVER THE
WRN INTERIOR AS PCPN WATER FALL TO LESS THAN .25 INCH UNDER LIGHT
WINDS...A PERIOD OF CLEARING SKIES AND FRESH SNOW COVER. COULD SEE
THE TYPICAL COLD SPOTS NEAR THE WI BORDER FALL NEAR ZERO.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 458 AM EST SAT DEC 27 2014
WILL START OUT 12Z SUNDAY WITH A COLD FRONT DRAPED ACROSS THE FAR W
CWA. THIS WILL BE THE FOCUS FOR LIGHT TO POTENTIALLY MODERATE SNOW
SHOWERS FROM AROUND ONTONAGON UP THROUGH THE KEWEENAW PENINSULA. AS
NOTED IN THE PREVIOUS DISCUSSION...A LES ADVISORY BY BE NEEDED FOR
ONTONAGON AND HOUGHTON COUNTIES. CURRENTLY FORECASTING 3-5IN OF NEW
SNOW IN THIS AREA OVERNIGHT THROUGH SUNDAY EVENING. WILL HOLD OFF ON
ISSUING ANYTHING AS ONTONAGON AND S HOUGHTON HAVE BEEN INCLUDED IN
THE INITIAL WINTER WX ADVISORY FOR TODAY.
WITH COOLER AIR SLIDING IN...LOOK FOR SNOW RATIOS TO BE ON THE
INCREASE...RANGING FROM AROUND 20-23:1 THROUGH MUCH OF THIS PERIOD.
THE SFC TROUGH WILL SLOWLY EXIT AS STRONG AND COLD HIGH PRESSURE
PUSHES FROM FAR NW CANADA SUNDAY TO BRITISH COLUMBIA/ALBERTA ON
MONDAY...WITH A SIZABLE RIDGE EXTENDING INTO THE UPPER GREAT LAKES.
THE LOWERING INVERSION HEIGHTS /AROUND 850MB AT IWD/ WILL START TO
BECOME A CONCERN FOR MODERATE/HEAVY SNOWFALL DEVELOPMENT FROM 00Z
MONDAY ON ACROSS THE CWA. STILL EXPECTING 12HR SNOW TOTALS OF 1-3IN
WHERE THE BEST CONVERGENCE DEVELOPS WITH PLENTY OF MOISTURE STILL
STUCK IN OUR STEADY NW FLOW INTO TUESDAY.
THE COLDEST AIR LOOKS TO SWING IN TUESDAY NIGHT...ON THE ORDER OF
-21 TO -24C. IF WINDS BECOME MORE WESTERLY AND THE INTERIOR W HALF
CLEARS OUT...THIS COULD BE A VERY CHILLY NIGHT. CURRENTLY CALLING
FOR -5 TO -10F LOWS BY DAYBREAK WEDNESDAY UNDER A PARTLY CLOUDY SKY.
THERE MAY BE A BRIEF REPRISE FROM THE STEADY NW TO WNW WINDS
WEDNESDAY INTO WEDNESDAY NIGHT. POPS/WX MAY NEED TO BE DIMINISHED
FROM THE CURRENT FCST FOR WEDNESDAY NIGHT IF THIS TREND HOLDS UP.
THERE IS PLENTY OF DISCREPANCIES BETWEEN THE AVAILABLE GUIDANCE AT
THIS POINT...VARYING FROM -20C 850MB AIR OVERHEAD ON GUSTY NW WINDS
/UP TO 40KTS AT 850MB/ FROM THE 27/00Z GFS...AND MORE W-WSW WINDS
WITH -12C 850MB TEMPERATURES OFF THE 26/12Z ECMWF. WILL KEEP GOING
WITH A GENERAL BLEND BETWEEN THE CONSENSUS AND OUR PREVIOUS FORECAST
BEYOND THIS POINT GIVEN THE MODERATE TO LOWER CONFIDENCE.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 626 AM EST SAT DEC 27 2014
EXPECT IFR/LIFR CONDITIONS THROUGH EARLY AFTERNOON AS LOW PRESSURE
OVER SOUTHERN WI LIFTS NORTHEAST TO NORTHERN LOWER MI THIS AFTERNOON.
THE LOW PRESSURE SYSTEM WILL BRING LIGHT TO MODERATE SNOWFALL ACROSS
WEST-CENTRAL UPPER MICHIGAN THROUGH EARLY THIS AFTERNOON. HAVE SHOWN
LOWERING TREND WITH CEILINGS/VISIBILITIES AS THIS SNOW MOVES
THROUGH...WITH THE WORST CONDITIONS AT KIWD AND ESPECIALLY
KSAW...WHERE CONDITIONS WILL FALL TO OR REMAIN LIFR INTO EARLY AFTERNOON.
THE LOW AND HEAVIER SNOW WILL QUICKLY DEPART NE AS CONDITIONS
IMPROVE TO MVFR BY MID AFTERNOON AND TO VFR SAT EVENING AT KIWD/KSAW.
COLDER AIR MOVING OVER LAKE SUPERIOR TONIGHT IN A WNW FLOW WILL HELP
DEVELOP LAKE EFFECT SNOW AT KCMX AND KIWD LATE SAT NIGHT. CONVERGENT
WESTERLY FLOW AND GUSTIER WINDS DEVELOPING COULD LEAD TO IFR
CONDITIONS AT KCMX IN SNOW/BLOWING SNOW.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 535 AM EST SAT DEC 27 2014
EXPECT GENERALLY LIGHT WINDS INTO THIS MORNING AS A WEAK PRESSURE
GRADIENT IS IN PLACE DUE TO A SURFACE TROUGH STALLED OVER THE
MACKINAC STRAITS. BUT AS A LOW LIFTS NORTHEAST OF THE STRAITS THIS
AFTERNOON INTO QUEBEC TONIGHT...NORTHWEST WINDS WILL BE ON THE
INCREASE THIS AFTERNOON AND EVENING WITH GUSTS UP TO 30KTS OVER EAST
HALF. BEHIND THE LOW...A WEAK SURFACE TROUGH WILL REMAIN IN PLACE ON
SUNDAY AND KEEP WEST-NORTHWEST WINDS UP TO 25KTS IN PLACE. A HIGH
PRESSURE RIDGE BUILDING INTO THE AREA ON MONDAY FROM A STRONG HIGH
IN THE NORTHERN/CENTRAL PLAINS WILL LEAD TO NORTHWEST TO NORTHERLY
WINDS UP TO 25-30KTS THROUGH TUESDAY. AN APPROACHING TROUGH FROM A
LOW OVER HUDSON BAY ON TUESDAY NIGHT WILL LEAD TO A TIGHTER PRESSURE
GRADIENT AND WESTERLY GALES TO 35-40KTS LATE TUESDAY NIGHT INTO
WEDNESDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ006-
007-014-085.
WINTER WEATHER ADVISORY UNTIL 4 PM EST /3 PM CST/ THIS AFTERNOON
FOR MIZ004-005-010>013.
WINTER WEATHER ADVISORY UNTIL 1 PM EST /NOON CST/ THIS AFTERNOON
FOR MIZ002-009-084.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...SRF
SHORT TERM...VOSS
LONG TERM...KF
AVIATION...VOSS
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
633 AM EST SAT DEC 27 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 535 AM EST SAT DEC 27 2014
LATEST WATER VAPOR LOOP AND RUC ANALYSIS SHOWS A VIGOROUS AND
WELL-DEFINED SHORTWAVE LIFTING NE INTO SRN MN AND NW WI WITH
DEVELOPING BAROCLINIC LEAF STRUCTURE/DEFORMATION ZONE. MID-LVL FGEN
ASSOC WITH SHORTWAVE STRETCHING FROM SRN MN AND NW WI INTO THE UPPER
MI HELPING SUPPORT LIGHT TO MODERATE SNOW.
TODAY...MID-LVL FGEN STRETCHING ACROSS THE UPPER MIDWEST TO THE
UPPER GREAT LAKES WILL CONTINUE TO SUPPORT MODERATE SNOW INTO EARLY
AFTERNOON. BROAD SCALE SYNOPTIC ASCENT WILL BE AIDED BY UPPER
DIVERGENCE IN THE LEFT EXIT REGION OF THE 300 MB JET. NEGATIVE EPV
NOTED ON CROSS-SECTIONS WITHIN A REGION OF MID-LVL FRONTOGENESIS
COULD LEAD TO SOME LOCALLY HEAVIER SNOW BANDS AS SFC LOW TRACKS JUST
SE OF AREA THIS MORNING AND THEN ACROSS THE STRAITS EARLY THIS AFTERNOON.
MODEL CONSENSUS QPF ARGUES FOR AREA OF HEAVIER SNOW JUST NW OF LOW
TRACK ALONG AND EAST OF A LINE FROM IRON RIVER THROUGH ISHPEMING
WHERE MODELS SHOW STRONG 285-290K ISENTROPIC ASCENT OVER A SIX-HR
PERIOD WITH 4 G/KG MIXR ADVECTING ACROSS AREA. THIS SWATH OF HEAVIER
SNOW WILL TAPER OFF BY MID AFTERNOON AS MID-LVL FGEN WEAKENS AND
BEGINS TO MOVE NE WITH DEPARTING SFC LOW. MODEL AVG QPF FM .25 INCH
WEST TO NEAR .5 INCH OVER PORTIONS OF THE CENTRAL CWA WITH EXPECTED
SNOW/WATER RATIOS FM 15/1 WEST TO NEAR 12/1 EAST HALF SHOULD YIELD
TOTAL SNOW ACCUMULATION FM 2-5 INCHES WEST TO 3-6 INCHES CENTRAL.
SINCE 6 INCH AMOUNTS SHOULD BE FAIRLY LOCALIZED WILL CONTINUE WITH
WINTER WX ADVISORY HEADLINES AT THIS POINT AND NOT UPGRADE TO
WARNINGS...BUT SITUATION WILL DEFINITELY WARRANT MONITORING THIS
MORNING. ALSO HAVE DECIDED TO INCLUDE ONTONAGON AND SRN HOUGHTON IN
ADVISORIES AS THEY SHOULD BE ON WRN EDGE OF HEAVIER QPF THIS MORNING.
TONIGHT...WITH SYSTEM SNOW OVER BY LATE AFTERNOON FOR EAST...EXPECT
TRANSITION TO PURE LAKE EFFECT SNOW TONIGHT AS 850MB TEMPS FALL FROM
-10 TO -12C IN THE EVENING TO -12 TO -16C BY 12Z SUN UNDER LOW-LEVEL
W TO WNW FLOW. LARGE SCALE DEEP LAYER Q-VECTOR DIVERGENCE WILL
DOMINATE THIS EVENING AND NAM/GFS FCST SOUNDINGS SHOWING INVERSIONS
BASED NEAR 4KFT...ANY DEVELOPING LES WILL BE ON THE LIGHT SIDE OVER
THE KEWEENAW. HOWEVER...LATER TONIGHT THERE IS A POTENTIAL FOR SOME
WEAK ENHANCEMENT AS A SHORTWAVE PASSES ACROSS NRN ONTARIO AND SENDS
A SFC TROF S ACROSS THE UPPER LAKES. GFS/NAM FCST SOUNDINGS SHOW AN
INCREASE IN MOISTURE DEPTH AND LIFTING OF THE INVERSION. THIS
ENHANCEMENT COMBINED WITH FAVORABLE PLACEMENT OF DGZ WITHIN
CONVECTIVE BOUNDARY LAYER AND SHARPENING OF THE WIND
SHIFT/CONVERGENCE AS TROF MOVES THROUGH AREA COULD YIELD MODERATE
SNOW LATE TONIGHT WITH A QUICK 1 TO LOCALLY 3 INCHES OF SNOW IN NRN
ONTONAGON/HOUGHTON COUNTIES WHERE SHARPEST CONVERGENCE IS INDICATED
AND WHERE UPSLOPING WILL FURTHER AID SNOW ACCUMULATIONS.
WENT ON COLDER SIDE OF GUIDANCE FOR MIN TEMPS ESPECIALLY OVER THE
WRN INTERIOR AS PCPN WATER FALL TO LESS THAN .25 INCH UNDER LIGHT
WINDS...A PERIOD OF CLEARING SKIES AND FRESH SNOW COVER. COULD SEE
THE TYPICAL COLD SPOTS NEAR THE WI BORDER FALL NEAR ZERO.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 458 AM EST SAT DEC 27 2014
WILL START OUT 12Z SUNDAY WITH A COLD FRONT DRAPED ACROSS THE FAR W
CWA. THIS WILL BE THE FOCUS FOR LIGHT TO POTENTIALLY MODERATE SNOW
SHOWERS FROM AROUND ONTONAGON UP THROUGH THE KEWEENAW PENINSULA. AS
NOTED IN THE PREVIOUS DISCUSSION...A LES ADVISORY BY BE NEEDED FOR
ONTONAGON AND HOUGHTON COUNTIES. CURRENTLY FORECASTING 3-5IN OF NEW
SNOW IN THIS AREA OVERNIGHT THROUGH SUNDAY EVENING. WILL HOLD OFF ON
ISSUING ANYTHING AS ONTONAGON AND S HOUGHTON HAVE BEEN INCLUDED IN
THE INITIAL WINTER WX ADVISORY FOR TODAY.
WITH COOLER AIR SLIDING IN...LOOK FOR SNOW RATIOS TO BE ON THE
INCREASE...RANGING FROM AROUND 20-23:1 THROUGH MUCH OF THIS PERIOD.
THE SFC TROUGH WILL SLOWLY EXIT AS STRONG AND COLD HIGH PRESSURE
PUSHES FROM FAR NW CANADA SUNDAY TO BRITISH COLUMBIA/ALBERTA ON
MONDAY...WITH A SIZABLE RIDGE EXTENDING INTO THE UPPER GREAT LAKES.
THE LOWERING INVERSION HEIGHTS /AROUND 850MB AT IWD/ WILL START TO
BECOME A CONCERN FOR MODERATE/HEAVY SNOWFALL DEVELOPMENT FROM 00Z
MONDAY ON ACROSS THE CWA. STILL EXPECTING 12HR SNOW TOTALS OF 1-3IN
WHERE THE BEST CONVERGENCE DEVELOPS WITH PLENTY OF MOISTURE STILL
STUCK IN OUR STEADY NW FLOW INTO TUESDAY.
THE COLDEST AIR LOOKS TO SWING IN TUESDAY NIGHT...ON THE ORDER OF
-21 TO -24C. IF WINDS BECOME MORE WESTERLY AND THE INTERIOR W HALF
CLEARS OUT...THIS COULD BE A VERY CHILLY NIGHT. CURRENTLY CALLING
FOR -5 TO -10F LOWS BY DAYBREAK WEDNESDAY UNDER A PARTLY CLOUDY SKY.
THERE MAY BE A BRIEF REPRISE FROM THE STEADY NW TO WNW WINDS
WEDNESDAY INTO WEDNESDAY NIGHT. POPS/WX MAY NEED TO BE DIMINISHED
FROM THE CURRENT FCST FOR WEDNESDAY NIGHT IF THIS TREND HOLDS UP.
THERE IS PLENTY OF DISCREPANCIES BETWEEN THE AVAILABLE GUIDANCE AT
THIS POINT...VARYING FROM -20C 850MB AIR OVERHEAD ON GUSTY NW WINDS
/UP TO 40KTS AT 850MB/ FROM THE 27/00Z GFS...AND MORE W-WSW WINDS
WITH -12C 850MB TEMPERATURES OFF THE 26/12Z ECMWF. WILL KEEP GOING
WITH A GENERAL BLEND BETWEEN THE CONSENSUS AND OUR PREVIOUS FORECAST
BEYOND THIS POINT GIVEN THE MODERATE TO LOWER CONFIDENCE.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 626 AM EST SAT DEC 27 2014
EXPECT IFR/LIFR CONDITIONS THROUGH EARLY AFTERNOON AS LOW PRESSURE
OVER SOUTHERN WI LIFTS NORTHEAST TO NORTHERN LOWER MI THIS AFTERNOON.
THE LOW PRESSURE SYSTEM WILL BRING LIGHT TO MODERATE SNOWFALL ACROSS
WEST-CENTRAL UPPER MICHIGAN THROUGH EARLY THIS AFTERNOON. HAVE SHOWN
LOWERING TREND WITH CEILINGS/VISIBILITIES AS THIS SNOW MOVES
THROUGH...WITH THE WORST CONDITIONS AT KIWD AND ESPECIALLY
KSAW...WHERE CONDITIONS WILL FALL TO OR REMAIN LIFR INTO EARLY AFTERNOON.
THE LOW AND HEAVIER SNOW WILL QUICKLY DEPART NE AS CONDITIONS
IMPROVE TO MVFR BY MID AFTERNOON AND TO VFR SAT EVENING AT KIWD/KSAW.
COLDER AIR MOVING OVER LAKE SUPERIOR TONIGHT IN A WNW FLOW WILL HELP
DEVELOP LAKE EFFECT SNOW AT KCMX AND KIWD LATE SAT NIGHT. CONVERGENT
WESTERLY FLOW AND GUSTIER WINDS DEVELOPING COULD LEAD TO IFR
CONDITIONS AT KCMX IN SNOW/BLOWING SNOW. &&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 535 AM EST SAT DEC 27 2014
EXPECT GENERALLY LIGHT WINDS INTO THIS MORNING AS A WEAK PRESSURE
GRADIENT IS IN PLACE DUE TO A SURFACE TROUGH STALLED OVER THE
MACKINAC STRAITS. BUT AS A LOW LIFTS NORTHEAST OF THE STRAITS THIS
AFTERNOON INTO QUEBEC TONIGHT...NORTHWEST WINDS WILL BE ON THE
INCREASE THIS AFTERNOON AND EVENING WITH GUSTS UP TO 30KTS OVER EAST
HALF. BEHIND THE LOW...A WEAK SURFACE TROUGH WILL REMAIN IN PLACE ON
SUNDAY AND KEEP WEST-NORTHWEST WINDS UP TO 25KTS IN PLACE. A HIGH
PRESSURE RIDGE BUILDING INTO THE AREA ON MONDAY FROM A STRONG HIGH
IN THE NORTHERN/CENTRAL PLAINS WILL LEAD TO NORTHWEST TO NORTHERLY
WINDS UP TO 25-30KTS THROUGH TUESDAY. AN APPROACHING TROUGH FROM A
LOW OVER HUDSON BAY ON TUESDAY NIGHT WILL LEAD TO A TIGHTER PRESSURE
GRADIENT AND WESTERLY GALES TO 35-40KTS LATE TUESDAY NIGHT INTO
WEDNESDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ006-
007-014-085.
WINTER WEATHER ADVISORY UNTIL 4 PM EST /3 PM CST/ THIS AFTERNOON
FOR MIZ004-005-010>013.
WINTER WEATHER ADVISORY UNTIL 1 PM EST /NOON CST/ THIS AFTERNOON
FOR MIZ002-009-084.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...KF
AVIATION...VOSS
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
610 AM EST SAT DEC 27 2014
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 328 AM EST SAT DEC 27 2014
WE WILL SEE THE LAST OF THE MILD WEATHER TODAY WITH INTERMITTENT
LIGHT RAIN AND DRIZZLE. COLDER AIR MOVES IN TONIGHT WITH A SECOND
WAVE OF ARCTIC AIR MONDAY NIGHT THROUGH WEDNESDAY. HIGHS ONLY IN THE 20S
ARE EXPECTED DURING THE MIDDLE PORTION OF THE WEEK AND MAY
STRUGGLE TO REACH 20 DEGREES ON WEDNESDAY...ESPECIALLY NORTH OF GRAND
RAPIDS. SNOW ACCUMULATIONS ALSO APPEAR POSSIBLE MONDAY NIGHT INTO
WEDNESDAY. TEMPERATURES WILL MODERATE SLIGHTLY TOWARD THE END OF
THE WORK WEEK BEFORE ANOTHER SURGE OF ARCTIC AIR NEXT WEEKEND.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 328 AM EST SAT DEC 27 2014
TEMPERATURES HAD RISEN INTO THE MID 40S MAINLY ALONG AND SOUTH OF
I-96 AS OF THIS WRITING. TEMPS AND DEWPOINTS WILL CONTINUE TO
CREEP UP THIS MORNING. 06Z HRRR CONTINUES TO INDICATE PERIODS OF
LIGHT RAIN AND DRIZZLE TODAY...THE FIRST AFTER 10Z OR SO.
THE WEAK SURFACE LOW IS FORECAST TO DEEPEN TO AROUND 1008 MB OVER
NORTHERN LOWER MI BY 18Z. THE COLD FRONT THEN MOVES THROUGH
FOLLOWED BY A VEERING OF THE WINDS DURING THE AFTERNOON. SURFACE
TEMPS ARE EXPECTED TO REMAIN ABOVE FREEZING AT 00Z THIS
EVENING...AND MOISTURE QUICKLY BAILS AFTER 00Z. THE ONSHORE FLOW
IS ALSO SLIGHTLY DIVERGENT. FORECAST THINKING HAS NOT
CHANGED...LITTLE IF ANY SNOW TONIGHT.
QUIET WEATHER EXPECTED ON SUNDAY. A VERY STRONG 1057 MB HIGH
DEVELOPS OVER WESTERN CANADA AND AN EXTENSION OF THIS HIGH
PRESSURE SYSTEM TURNS LOW LEVEL FLOW NORTHEASTERLY BY MONDAY.
THINKING PARTLY SUNNY FOR NOW WITH HIGHS IN THE LOW TO MID 30S.
.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 328 AM EST SAT DEC 27 2014
MODELS ARE IN DECENT AGREEMENT IN SHOWING A DEEPENING UPPER LOW OVER
HUDSON BAY AS WE HEAD THROUGH THE EXTENDED PERIOD. THIS WILL RESULT
IN A COLDER THAN NORMAL PERIOD THROUGH THE LONG TERM PERIOD.
THE ARCTIC AIR WILL ARRIVE IN WAVES. MONDAY NIGHT THROUGH WEDNESDAY
WILL FEATURE COLD AIR ADVECTION. THE LOW LEVEL THERMAL TROUGH
PUSHES THROUGH ON WEDNESDAY. HIGHS ON WEDNESDAY MAY STRUGGLE TO
REACH 20 DEGREES...ESPECIALLY NORTH OF GRAND RAPIDS. WIND WILL
ACCOMPANY THIS ARCTIC AIRMASS AND SUB ZERO WIND CHILLS WILL OCCUR AT
TIMES. ALSO MODELS HAVE BEEN TRENDING TOWARD MORE MOISTURE IN THE
DGZ MON NIGHT INTO WED. THUS WE MAY END UP WITH SOME
ACCUMULATIONS. I DID TREND POPS UPWARD BASED ON THE TRENDS.
TEMPERATURES ARE LIKELY TO MODERATE SLIGHTLY THURSDAY INTO FRIDAY AS
WARM AIR ADVECTION DEVELOPS ON THE BACKSIDE OF THE DEPARTING
HIGH. THEY ARE EXPECTED TO STILL AVERAGE OUT BELOW NORMAL.
ANOTHER SURGE OF ARCTIC AIR WILL LIKELY PUSH IN OVER NEXT WEEKEND.
THIS IS WHEN THE SOUTHERN ROCKIES LOW KICKS OUT INTO THE PLAINS AND
TRACKS TO THE CENTRAL APPALACHIANS. AS THIS WAVE TRACKS EAST...AN
IMPRESSIVE SURGE OF ARCTIC AIR SINKS SOUTH THROUGH THE GREAT LAKES
REGION. THERE IS A RISK FOR SNOW ASSOCIATED WITH THE ARRIVAL OF
THIS NEXT REINFORCING SHOT OF ARCTIC AIR. OVERALL MODELS HAVE COME
INTO BETTER AGREEMENT OF THE TIMING AND DURATION OF THIS NEXT ARCTIC
AIRMASS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 607 AM EST SAT DEC 27 2014
THE MAIN CHALLENGE IN THE AVIATION FORECAST DEALS WITH THE
POTENTIAL FOR IMPACT CEILINGS AND VISIBILITIES.
WHILE DELAYED...THE IFR IS DEVELOPING OVER IN INDIANA AND
ILLINOIS...AND HAS NOW MOVED INTO THE KBEH REGION. THIS LOW LEVEL
MOISTURE WILL BE TRACKING NORTHWARD INTO SOUTHWEST LOWER MI THIS
MORNING. THE LOW CONDITIONS WILL THEN PERSIST THROUGH MUCH OF THE
AFTERNOON. IMPROVING CONDITIONS ARE FORECASTED FOR LATER TODAY AS
THE WIND VEERS WITH TIME ALLOWING A COLDER/DRIER AIRMASS TO ARRIVE
FROM THE WEST.
&&
.MARINE...
ISSUED AT 328 AM EST SAT DEC 27 2014
A SMALL CRAFT ADVISORY HAS BEEN ISSUED FOR 11 AM TODAY THROUGH 11
AM SUNDAY. AS THE SURFACE LOW APPROACHES...SOUTHERLY WINDS WILL
INCREASE TO 15 TO 25 KNOTS TODAY. WINDS WILL VEER WEST TO 30 KNOTS
LATE THIS AFTERNOON AND EVENING. WAVES WILL BUILD TO 4 TO 8 FEET
NORTH OF HOLLAND AND 3 TO 5 FEET SOUTH OF HOLLAND. WEST WINDS WILL
VEER NORTHWESTERLY TONIGHT.
&&
.HYDROLOGY...
ISSUED AT 328 AM EST SAT DEC 27 2014
AROUND A TENTH OF AN INCH OR LESS OF RAINFALL IS EXPECTED
TODAY...WITH SLIGHTLY HIGHER AMOUNTS POSSIBLE TOWARD LUDINGTON.
THIS LIGHT RAINFALL IS NOT EXPECTED TO HAVE A SIGNIFICANT IMPACT
ON RIVERS. ALL RIVER FLOOD ADVISORIES HAVE BEEN CANCELED.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY FROM 11 AM THIS MORNING TO 11 AM EST SUNDAY
FOR LMZ844>849.
&&
$$
SYNOPSIS...EBW
SHORT TERM...EBW
LONG TERM...MJS
AVIATION...MJS
HYDROLOGY...EBW
MARINE...EBW
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
539 AM EST SAT DEC 27 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 535 AM EST SAT DEC 27 2014
LATEST WATER VAPOR LOOP AND RUC ANALYSIS SHOWS A VIGOROUS AND
WELL-DEFINED SHORTWAVE LIFTING NE INTO SRN MN AND NW WI WITH
DEVELOPING BAROCLINIC LEAF STRUCTURE/DEFORMATION ZONE. MID-LVL FGEN
ASSOC WITH SHORTWAVE STRETCHING FROM SRN MN AND NW WI INTO THE UPPER
MI HELPING SUPPORT LIGHT TO MODERATE SNOW.
TODAY...MID-LVL FGEN STRETCHING ACROSS THE UPPER MIDWEST TO THE
UPPER GREAT LAKES WILL CONTINUE TO SUPPORT MODERATE SNOW INTO EARLY
AFTERNOON. BROAD SCALE SYNOPTIC ASCENT WILL BE AIDED BY UPPER
DIVERGENCE IN THE LEFT EXIT REGION OF THE 300 MB JET. NEGATIVE EPV
NOTED ON CROSS-SECTIONS WITHIN A REGION OF MID-LVL FRONTOGENESIS
COULD LEAD TO SOME LOCALLY HEAVIER SNOW BANDS AS SFC LOW TRACKS JUST
SE OF AREA THIS MORNING AND THEN ACROSS THE STRAITS EARLY THIS AFTERNOON.
MODEL CONSENSUS QPF ARGUES FOR AREA OF HEAVIER SNOW JUST NW OF LOW
TRACK ALONG AND EAST OF A LINE FROM IRON RIVER THROUGH ISHPEMING
WHERE MODELS SHOW STRONG 285-290K ISENTROPIC ASCENT OVER A SIX-HR
PERIOD WITH 4 G/KG MIXR ADVECTING ACROSS AREA. THIS SWATH OF HEAVIER
SNOW WILL TAPER OFF BY MID AFTERNOON AS MID-LVL FGEN WEAKENS AND
BEGINS TO MOVE NE WITH DEPARTING SFC LOW. MODEL AVG QPF FM .25 INCH
WEST TO NEAR .5 INCH OVER PORTIONS OF THE CENTRAL CWA WITH EXPECTED
SNOW/WATER RATIOS FM 15/1 WEST TO NEAR 12/1 EAST HALF SHOULD YIELD
TOTAL SNOW ACCUMULATION FM 2-5 INCHES WEST TO 3-6 INCHES CENTRAL.
SINCE 6 INCH AMOUNTS SHOULD BE FAIRLY LOCALIZED WILL CONTINUE WITH
WINTER WX ADVISORY HEADLINES AT THIS POINT AND NOT UPGRADE TO
WARNINGS...BUT SITUATION WILL DEFINITELY WARRANT MONITORING THIS
MORNING. ALSO HAVE DECIDED TO INCLUDE ONTONAGON AND SRN HOUGHTON IN
ADVISORIES AS THEY SHOULD BE ON WRN EDGE OF HEAVIER QPF THIS MORNING.
TONIGHT...WITH SYSTEM SNOW OVER BY LATE AFTERNOON FOR EAST...EXPECT
TRANSITION TO PURE LAKE EFFECT SNOW TONIGHT AS 850MB TEMPS FALL FROM
-10 TO -12C IN THE EVENING TO -12 TO -16C BY 12Z SUN UNDER LOW-LEVEL
W TO WNW FLOW. LARGE SCALE DEEP LAYER Q-VECTOR DIVERGENCE WILL
DOMINATE THIS EVENING AND NAM/GFS FCST SOUNDINGS SHOWING INVERSIONS
BASED NEAR 4KFT...ANY DEVELOPING LES WILL BE ON THE LIGHT SIDE OVER
THE KEWEENAW. HOWEVER...LATER TONIGHT THERE IS A POTENTIAL FOR SOME
WEAK ENHANCEMENT AS A SHORTWAVE PASSES ACROSS NRN ONTARIO AND SENDS
A SFC TROF S ACROSS THE UPPER LAKES. GFS/NAM FCST SOUNDINGS SHOW AN
INCREASE IN MOISTURE DEPTH AND LIFTING OF THE INVERSION. THIS
ENHANCEMENT COMBINED WITH FAVORABLE PLACEMENT OF DGZ WITHIN
CONVECTIVE BOUNDARY LAYER AND SHARPENING OF THE WIND
SHIFT/CONVERGENCE AS TROF MOVES THROUGH AREA COULD YIELD MODERATE
SNOW LATE TONIGHT WITH A QUICK 1 TO LOCALLY 3 INCHES OF SNOW IN NRN
ONTONAGON/HOUGHTON COUNTIES WHERE SHARPEST CONVERGENCE IS INDICATED
AND WHERE UPSLOPING WILL FURTHER AID SNOW ACCUMULATIONS.
WENT ON COLDER SIDE OF GUIDANCE FOR MIN TEMPS ESPECIALLY OVER THE
WRN INTERIOR AS PCPN WATER FALL TO LESS THAN .25 INCH UNDER LIGHT
WINDS...A PERIOD OF CLEARING SKIES AND FRESH SNOW COVER. COULD SEE
THE TYPICAL COLD SPOTS NEAR THE WI BORDER FALL NEAR ZERO.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 458 AM EST SAT DEC 27 2014
WILL START OUT 12Z SUNDAY WITH A COLD FRONT DRAPED ACROSS THE FAR W
CWA. THIS WILL BE THE FOCUS FOR LIGHT TO POTENTIALLY MODERATE SNOW
SHOWERS FROM AROUND ONTONAGON UP THROUGH THE KEWEENAW PENINSULA. AS
NOTED IN THE PREVIOUS DISCUSSION...A LES ADVISORY BY BE NEEDED FOR
ONTONAGON AND HOUGHTON COUNTIES. CURRENTLY FORECASTING 3-5IN OF NEW
SNOW IN THIS AREA OVERNIGHT THROUGH SUNDAY EVENING. WILL HOLD OFF ON
ISSUING ANYTHING AS ONTONAGON AND S HOUGHTON HAVE BEEN INCLUDED IN
THE INITIAL WINTER WX ADVISORY FOR TODAY.
WITH COOLER AIR SLIDING IN...LOOK FOR SNOW RATIOS TO BE ON THE
INCREASE...RANGING FROM AROUND 20-23:1 THROUGH MUCH OF THIS PERIOD.
THE SFC TROUGH WILL SLOWLY EXIT AS STRONG AND COLD HIGH PRESSURE
PUSHES FROM FAR NW CANADA SUNDAY TO BRITISH COLUMBIA/ALBERTA ON
MONDAY...WITH A SIZABLE RIDGE EXTENDING INTO THE UPPER GREAT LAKES.
THE LOWERING INVERSION HEIGHTS /AROUND 850MB AT IWD/ WILL START TO
BECOME A CONCERN FOR MODERATE/HEAVY SNOWFALL DEVELOPMENT FROM 00Z
MONDAY ON ACROSS THE CWA. STILL EXPECTING 12HR SNOW TOTALS OF 1-3IN
WHERE THE BEST CONVERGENCE DEVELOPS WITH PLENTY OF MOISTURE STILL
STUCK IN OUR STEADY NW FLOW INTO TUESDAY.
THE COLDEST AIR LOOKS TO SWING IN TUESDAY NIGHT...ON THE ORDER OF
-21 TO -24C. IF WINDS BECOME MORE WESTERLY AND THE INTERIOR W HALF
CLEARS OUT...THIS COULD BE A VERY CHILLY NIGHT. CURRENTLY CALLING
FOR -5 TO -10F LOWS BY DAYBREAK WEDNESDAY UNDER A PARTLY CLOUDY SKY.
THERE MAY BE A BRIEF REPRISE FROM THE STEADY NW TO WNW WINDS
WEDNESDAY INTO WEDNESDAY NIGHT. POPS/WX MAY NEED TO BE DIMINISHED
FROM THE CURRENT FCST FOR WEDNESDAY NIGHT IF THIS TREND HOLDS UP.
THERE IS PLENTY OF DISCREPANCIES BETWEEN THE AVAILABLE GUIDANCE AT
THIS POINT...VARYING FROM -20C 850MB AIR OVERHEAD ON GUSTY NW WINDS
/UP TO 40KTS AT 850MB/ FROM THE 27/00Z GFS...AND MORE W-WSW WINDS
WITH -12C 850MB TEMPERATURES OFF THE 26/12Z ECMWF. WILL KEEP GOING
WITH A GENERAL BLEND BETWEEN THE CONSENSUS AND OUR PREVIOUS FORECAST
BEYOND THIS POINT GIVEN THE MODERATE TO LOWER CONFIDENCE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1223 AM EST SAT DEC 27 2014
MVFR CIGS WILL GIVE WAY TO IFR/LIFR CONDITIONS BY LATE TONIGHT OR
EARLY SATURDAY AS LOW PRESSURE OVER SE IA LIFTS NORTHEAST TO NORTHERN
LOWER MI SAT AFTERNOON. THE LOW PRESSURE SYSTEM WILL BRING LIGHT TO
OCCASIONALLY MODERATE SNOWFALL ACROSS WEST-CENTRAL UPPER MICHIGAN
OVERNIGHT THROUGH SATURDAY MORNING. HAVE SHOWN LOWERING
CEILINGS/VISIBILITIES AS THIS SNOW MOVES THROUGH...WITH THE WORST
CONDITIONS AT KIWD AND ESPECIALLY KSAW...WHERE CONDITIONS WILL FALL
TO OR REMAIN LIFR. THE LOW AND HEAVIER SNOW WILL QUICKLY DEPART
SATURDAY AFTERNOON AND LEAD TO IMPROVING CONDITIONS TO MVFR THE
AFTERNOON AND TO VFR SAT EVENING.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 535 AM EST SAT DEC 27 2014
EXPECT GENERALLY LIGHT WINDS INTO THIS MORNING AS A WEAK PRESSURE
GRADIENT IS IN PLACE DUE TO A SURFACE TROUGH STALLED OVER THE
MACKINAC STRAITS. BUT AS A LOW LIFTS NORTHEAST OF THE STRAITS THIS
AFTERNOON INTO QUEBEC TONIGHT...NORTHWEST WINDS WILL BE ON THE
INCREASE THIS AFTERNOON AND EVENING WITH GUSTS UP TO 30KTS OVER EAST
HALF. BEHIND THE LOW...A WEAK SURFACE TROUGH WILL REMAIN IN PLACE ON
SUNDAY AND KEEP WEST-NORTHWEST WINDS UP TO 25KTS IN PLACE. A HIGH
PRESSURE RIDGE BUILDING INTO THE AREA ON MONDAY FROM A STRONG HIGH
IN THE NORTHERN/CENTRAL PLAINS WILL LEAD TO NORTHWEST TO NORTHERLY
WINDS UP TO 25-30KTS THROUGH TUESDAY. AN APPROACHING TROUGH FROM A
LOW OVER HUDSON BAY ON TUESDAY NIGHT WILL LEAD TO A TIGHTER PRESSURE
GRADIENT AND WESTERLY GALES TO 35-40KTS LATE TUESDAY NIGHT INTO
WEDNESDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ006-
007-014-085.
WINTER WEATHER ADVISORY UNTIL 4 PM EST /3 PM CST/ THIS AFTERNOON
FOR MIZ004-005-010>013.
WINTER WEATHER ADVISORY UNTIL 1 PM EST /NOON CST/ THIS AFTERNOON
FOR MIZ002-009-084.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...KF
AVIATION...JLB
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
558 AM CST SAT DEC 27 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 329 AM CST SAT DEC 27 2014
AFTER TAKING MOST OF DECEMBER OFF...THE SHORT TERM PERIOD MARKS THE
BEGINNING OF THE RETURN OF WEATHER THAT IS MORE TYPICAL OF WHAT WE
WOULD EXPECT IN THE HEART OF WINTER...AT LEAST FOR TEMPERATURES.
FEATURE DRIVING SNOW ACROSS THE AREA THIS MORNING SHOWS UP WELL ON
SATELLITE WITH A NICE SWIRL MOVING INTO THE SIOUX FALLS AREA...WITH
A NICE DRY SLOT NOSING INTO SE MN. THIS DRY SLOT IS ASSOCIATED WITH
A TROWAL...WHICH HAS HELPED FORCE A NICE DEFORMATION BAND OF PRECIP
TO THE NW OF IT. MODELS GOING BACK TO THE 00Z RUNS LAST NIGHT HAVE
ACTUALLY DONE A GOOD JOB HANDLING THIS SNOW AND PRETTY MUCH FOLLOWED
THE HOPWRF AND HRRR FOR ENDING SNOW ACROSS THE AREA THIS MORNING.
EVERYTHING APPEARS ON TRACK FOR A HEALTHY SWATH OF 3 TO 5 INCHES.
BACK TO THE WEST OF THIS LOW...THERE IS A RIDGE AXIS EXTENDING FROM
ERN COLORADO UP INTO THE ERN DAKOTAS. TEMPS AND DEWPS FALL OFF TO
WITHIN 10 DEGS OF EITHER SIDE OF ZERO WITHIN THE RIDGE AXIS...THOUGH
THIS RIDGE AXIS ALSO HAS WHAT HAS BEEN A RARITY THIS MONTH...MOSTLY
CLEAR SKIES. ITS LOOKING LIKE GOOD BET FOR SEEING SOME SUN TODAY
WEST OF I-35. EAST OF I-35...THE CLEARING WILL BE RACING
SUNSET...THOUGH BY THE TIME YOU GET TO EAU CLAIRE...IT`S A PRETTY
GOOD BET THAT SKIES WILL REMAIN OVERCAST THROUGH THE DURATION OF
DAYLIGHT HOURS. THESE MAINLY CLEAR SKIES MAY CAUSE TEMPERATURES TO
BE A BIT COOLER THAN WHAT IS CURRENTLY FORECAST TONIGHT...ESPECIALLY
WHERE WE ARE SEEING SNOW RIGHT NOW FROM SOUTHERN MN INTO WRN WI. OF
COURSE OUR TIME WITH CLEARISH SKIES WILL BE SHORT LIVED...AS BY 12Z
SUNDAY...THE ARCTIC BOUNDARY WILL BE SLIPPING INTO CENTRAL MN...WITH
CLOUD COVER INCREASING AHEAD OF THE FRONT AS IT DROPS SOUTH ACROSS
NRN MN THROUGH THE NIGHT.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 329 AM CST SAT DEC 27 2014
THE MAIN HIGHLIGHT OF THE LONG TERM FORECAST PERIOD WILL BE THE
RETURN TO BELOW NORMAL TEMPERATURES BEFORE WE RING IN THE NEW
YEAR. OTHER THAN A SLIM CHANCE FOR SNOWFALL ON SUNDAY NIGHT INTO
MONDAY AS THE ARCTIC BOUNDARY RESPONSIBLE FOR THE AFOREMENTIONED
COOL DOWN IN TEMPERATURES MOVES THROUGH...DRY WEATHER IS EXPECTED
UNTIL POSSIBLY NEXT FRIDAY.
SUNDAY WILL LIKELY BE THE ONE AND ONLY MILD DAY THROUGH MOST OF
THE UPCOMING WEEK IN ADVANCE OF THE COLD FRONT. MODEL AGREEMENT WITH
THIS FEATURE HAS NOT REALLY SHOWN MUCH IMPROVEMENT OVER THE LAST
24 HOURS. THE ECMWF HAS BEEN FAIRLY INSISTENT THAT THE FORECAST
AREA WILL MISS OUT ON SNOWFALL WITH THIS FEATURE...WHILE THE
SREF...NAM...AND NOW 27.00 GFS THINK SOUTHERN MN WILL SEE A 1-3
INCH SNOWFALL ON SUNDAY NIGHT AND MONDAY MORNING. SINCE THE ECMWF
IS A BIT OF AN OUTLIER FROM THE OVERALL MODEL CONSENSUS SOLUTION...WHICH
HAS SHOWN UP FOR MULTIPLE RUNS...HAVE INCLUDED 30 POPS FOR 00Z-18Z
MONDAY GENERALLY SOUTH OF INTERSTATE 94. HAVE HOWEVER KEPT SNOWFALL
ACCUMULATIONS AROUND ONE INCH OR LESS WITH THE THOUGHT THE
FORCING/MOISTURE MIGHT BE WEAKER/LOWER THAN PROGGED BY THE
CONSENSUS.
WHILE CONFIDENCE IS RATHER LOW WITH RESPECT TO SNOWFALL CHANCES AS
THIS BOUNDARY SURGES ACROSS THE AREA...WHAT IS MORE CERTAIN IS
THAT A BLAST OF COLDER AIR WILL FOLLOW IN ITS WAKE. THERE IS STILL
FINE AGREEMENT THAT H85 TEMPERATURES WILL REDUCE TO -18C TO -20C
BY TUESDAY. SUB-ZERO LOWS FOR TUESDAY AND WEDNESDAY MORNINGS ARE
FAIRLY CERTAIN...ALONG WITH HIGHS IN THE SINGLE DIGITS TO LOW
TEENS. WIND CHILLS WILL SNEAK TO AROUND -20F TO -30F ON MONDAY
NIGHT AND TUESDAY NIGHT...BUT MODERATE A TAD /-10F/ FOR NEW YEARS
EVE AS LOW TEMPERATURES RECOVER TO ABOVE ZERO VALUES.
AT THE END OF THE UPCOMING WEEK...GFS AND ECMWF MODELS FORECAST ANOTHER
WAVE TO DROP SOUTH FROM CANADA...THIS TIME THROUGH THE BASE OF A
HUDSON/JAMES BAY CYCLONE. WHILE TIMING/AMPLITUDE DETAILS ARE A BIT
UP IN THE AIR AT THIS POINT...THE PROGS DO WARRANT INCLUSION OF
20-30 POPS FOR SNOW ON FRIDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 542 AM CST SAT DEC 27 2014
ONLY REAL CHANGE MADE TO SNOW WITH 12Z TAFS WAS TO DELAY
IMPROVEMENTS BY ABOUT AN HOUR AS IFR VSBYS STILL EXTENDED BACK TO
THE WRN EDGE OF THE MN/IA BORDER. SNOW WILL RAPIDLY PULL OUT THIS
MORNING...AND DRIER AIR COMING IN FROM THE DAKOTAS WILL ALSO CLEAR
OUT THE STRATUS...FOLLOWED A RAP TIMING FOR THOSE IMPROVEMENTS.
OTHERWISE...WINDS WILL VEER OVER TO THE WSW THIS AFTERNOON AS A
COLD FRONT DROPS INTO NRN MN. THIS FRONT WILL MOVE INTO CENTRAL MN
AFTER 9Z AND MAY BRING A RENEWED THREAT OF MVFR CIGS...BUT NO SNOW
IS EXPECTED WITH THIS BOUNDARY. REALLY...ONLY PART OF FORECAST
THAT HAS LOWER CONFIDENCE IS TIMING OF CIG IMPROVEMENTS TO VFR.
KMSP...BASED ON THE RAP/HRRR...EXPECT IFR VIS SNOW TO END BETWEEN
14Z AND 15Z...WITH ALL SNOW DONE BY 17Z. KEPT THE CIG IMPROVEMENT
AT 20Z...THOUGH THE RAP/HRRR WOULD SAY THAT COULD TAKE TO AS LONG
AS 00Z TO GET HERE. ARCTIC FRONT WILL WORK ACROSS THE FIELD LATE
SUNDAY MORNING. THOUGH NO PRECIP IS EXPECTED...WE MAY SEE CIGS
COME BACK DOWN TO MVFR FOR A BIT IN ITS WAKE.
/OUTLOOK FOR KMSP/
SUN...VFR...CHC MVFR CIGS. WINDS BCMG NE 5-10 KTS.
MON...VFR. WINDS N 10 KTS.
TUE...VFR. WINDS NW 5-10 KTS
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER WEATHER ADVISORY UNTIL 9 AM CST THIS MORNING FOR MNZ053-
060>063-065>070-073>078-082>085-091>093.
WI...WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR WIZ014>016-
023>028.
&&
$$
SHORT TERM...MPG
LONG TERM...LS
AVIATION...MPG
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
936 AM CST SAT DEC 27 2014
.UPDATE...
ISSUED AT 935 AM CST SAT DEC 27 2014
AREA OF LIGHT SNOW CONTINUES TO PUSH ACROSS THE NRN VALLEY SO WILL
KEEP POPS/PCPN AS IS FOR NOW. OTHERWISE...REST OF FORECAST ON
TARGET.
UPDATE ISSUED AT 710 AM CST SAT DEC 27 2014
WEAK RETURNS ASSOCIATED WITH LIGHT SNOW WHICH HAS MOVED ACROSS THE
HWY 2 CORRIDOR THE LAST 4 HOURS IS WEAKENING AS IT MOVES INTO THE
CWA...HOWEVER WE ARE SEEING REPORTS OF LIGHT SNOW (LIKELY
FLURRIES) FROM THE I 94 CORRIDOR NORTH. WILL CONTINUE FLURRIES FOR
AREAS OUTSIDE AREAS DEPICTED ON RADAR AND CONTINUE THE MENTION OF
MEASURABLE SNOW ACROSS THE FAR NORTH UNTIL MORNING SNOW REPORTS
COME IN...AS A TENTH OF AN INCH NOT OUT OF THE QUESTION BUT
CONFIDENCE IS DECREASING WITH LATEST RADAR TRENDS.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 402 AM CST SAT DEC 27 2014
SKY COVER AND RELATED TEMPERATURES WILL BE THE FORECAST CHALLENGE
FOR TODAY AND TONIGHT. EASTERN NORTH DAKOTA IS CURRENTLY SEEING AN
INCREASE IN CLOUD COVER AND FILLING IN A BAND OF CLEAR SKIES FROM
ABOUT THE RRV TO DEVILS LAKE. THAN NAM12 AND RUC13 MODELS ARE
DOING A DECENT JOB DEPICTING THE CLEAR BAND AND USED THOSE MODELS
FOR GUIDANCE. ANOTHER CHALLENGE WILL BE ASSOCIATED LIGHT SNOW OR
FLURRIES AS SOME WEAK VORTICES MOVE ACROSS SRN CANADA.
TODAY...LOW CLOUDS TO THE EAST WILL PROGRESS SLOWER THAN THE
CLOUDS MOVING IN FROM THE WEST AND FILL IN THE CLEAR GAP OVER
NORTHEASTERN ND BY MID MORNING. SOME LIGHT SNOW NOW JUST EAST OF
MINOT WILL TRACK ACROSS NORTHERN ND AND INTO N CNTRL MN...AND
MODELS ARE SHOWING THIS MOVING EAST OF CWA BY 21Z. HAVE INTRODUCED
SOME LOW POPS AND ISOLATED SHSN FOR THIS AS WV IS SHOWING A COUPLE
OF WAVES MOVING ACROSS SRN CANADA THAT ARE PROVIDING ENOUGH LIFT
TO GENERATE SOME LIGHT SNOW. EXPECT NO MORE THAN A COUPLE OF
TENTHS OF AN INCH OF FLUFF ACROSS THE FAR NORTH...AND RATHER
SPOTTY IN NATURE. SOUTHERN ZONES WILL BE MORE CHALLENGING AS SAT
TRENDS DO NOT GIVE ME A LOT OF CONFIDENCE THAT THE SRN VALLEY WILL
SEE CLOUDS MOVE IN...AND IF IT REMAINS CLEAR COULD BE WARMER THAN
FCST HIGHS.
TONIGHT...AN ARCTIC AIRMASS WILL BEGIN SINKING SOUTH AND THE DRIER
AIR SHOULD HELP CLEAR THINGS OUT AT LEAST IN THE NORTH. WILL SEE A
LARGE TEMP GRADIENT ACROSS CWA FROM NW TO SE AS LINGERING CLOUDS
IN THE FAR SE COULD KEEP OVERNIGHT LOWS IN THE LOW TEENS WHEREAS
THE NW SHOULD SEE TEMPS FALL INTO DOUBLE DIGITS BELOW ZERO AS THE
COLD AIRMASS DROPS INTO THE REGION.
SUNDAY...ARCTIC AIR MASS SINKING SOUTH WILL BRING AN INCREASE IN
SOLAR BUT MUCH COLDER AND DRIER AIR. DAYTIME HIGHS WILL STRUGGLE
TO RECOVER TO ABOVE ZERO TEMPS ACROSS THE NORTH...WHILE THE
SOUTHERN ZONES WILL LIKELY SEE EARLY HIGHS AS EARLY MORNING CLOUDS
KEEP SAT NIGHT LOWS IN THE MID TEENS PRIOR TO COLDER AIR MAKING IT
TO THE SOUTHERN ZONES. SHOULD SEE STEADY TO FALLING TEMPS IN THE AFTN.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 402 AM CST SAT DEC 27 2014
SUNDAY NIGHT THROUGH MONDAY NIGHT...SFC HIGH WILL MOVE OVER MT AND
DAKOTAS AND MN SHOULD SEE LIGHT NW FLOW...WHICH WILL KEEP MON
NIGHT LOWS FROM PLUMMETING TOO FAR BUT DOUBLE DIGITS BELOW ZERO
TEMPS ARE EXPECTED. ADDITIONALLY THE LIGHT NW WINDS WILL BE
SUFFICIENT TO BRING WIND CHILLS TO ADVISORY LEVELS BOTH MON AND
TUE MORNING. THE COLD APPARENT TEMPS BOTH MORNINGS WILL BE THE
MOST SIGNIFICANT WX HAZARD WITHIN THE SHORT TERM PERIOD.
WEDNESDAY THROUGH SATURDAY...THE DEEP LONG WAVE TROF OVER CENTRAL NOAM
EARLY IN THE WEEK SHOWS A DISTINCT SHIFT INTO THE EAST AT MIDWEEK
AND A RETURN TO A MORE ZONAL FLOW PATTERN ACROSS THE NORTHERN
PLAINS BY THE LATE WEEK PERIOD. EXPECT ARCTIC AIRMASS TO MODERATE
TO NEAR SEASONAL NORMALS WED INTO FRI...WITH AN ADDITIONAL SHOT OF
COLD AIR MOVING IN BY THE WEEK END. PRECIPITATION CHANCES ARE LOW
THROUGH THE PERIOD WITH OCCASIONAL LIGHT SNOW OR FLURRIES
POSSIBLE LATE THURSDAY INTO SATURDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 710 AM CST SAT DEC 27 2014
MVFR CIGS WILL PERSIST THROUGH THE DAY IN NORTHWEST AND W CNTRL
MN...WHILE VFR CIGS MOVE ACROSS EASTERN ND. MOS GUIDANCE
INDICATING THOSE CIGS LOWERING INTO MVFR RANGE...BUT WILL HOLD OFF
UNTIL SFC WINDS SHIFT TO NORTH THIS EVENING AND LOWER CIGS OVER
SRN MB BEGIN ADVECTING SOUTH. FAR WILL BE CLEAR FOR MUCH OF THE
MORNING BEFORE VFR DECK ARRIVES IN THE LATE MORNING. DVL/TVF/GFK
MAY SEE SOME LIGHT FLURRIES THROUGH MID AFTN...BUT NO REDUCTIONS
TO VSBY EXPECTED.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...HOPKINS
SHORT TERM...SPEICHER
LONG TERM...GUST/SPEICHER
AVIATION...SPEICHER
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
710 AM CST SAT DEC 27 2014
.UPDATE...
ISSUED AT 710 AM CST SAT DEC 27 2014
WEAK RETURNS ASSOCIATED WITH LIGHT SNOW WHICH HAS MOVED ACROSS THE
HWY 2 CORRIDOR THE LAST 4 HOURS IS WEAKENING AS IT MOVES INTO THE
CWA...HOWEVER WE ARE SEEING REPORTS OF LIGHT SNOW (LIKELY
FLURRIES) FROM THE I 94 CORRIDOR NORTH. WILL CONTINUE FLURRIES FOR
AREAS OUTSIDE AREAS DEPICTED ON RADAR AND CONTINUE THE MENTION OF
MEASURABLE SNOW ACROSS THE FAR NORTH UNTIL MORNING SNOW REPORTS
COME IN...AS A TENTH OF AN INCH NOT OUT OF THE QUESTION BUT
CONFIDENCE IS DECREASING WITH LATEST RADAR TRENDS.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 402 AM CST SAT DEC 27 2014
SKY COVER AND RELATED TEMPERATURES WILL BE THE FORECAST CHALLENGE
FOR TODAY AND TONIGHT. EASTERN NORTH DAKOTA IS CURRENTLY SEEING AN
INCREASE IN CLOUD COVER AND FILLING IN A BAND OF CLEAR SKIES FROM
ABOUT THE RRV TO DEVILS LAKE. THAN NAM12 AND RUC13 MODELS ARE
DOING A DECENT JOB DEPICTING THE CLEAR BAND AND USED THOSE MODELS
FOR GUIDANCE. ANOTHER CHALLENGE WILL BE ASSOCIATED LIGHT SNOW OR
FLURRIES AS SOME WEAK VORTICES MOVE ACROSS SRN CANADA.
TODAY...LOW CLOUDS TO THE EAST WILL PROGRESS SLOWER THAN THE
CLOUDS MOVING IN FROM THE WEST AND FILL IN THE CLEAR GAP OVER
NORTHEASTERN ND BY MID MORNING. SOME LIGHT SNOW NOW JUST EAST OF
MINOT WILL TRACK ACROSS NORTHERN ND AND INTO N CNTRL MN...AND
MODELS ARE SHOWING THIS MOVING EAST OF CWA BY 21Z. HAVE INTRODUCED
SOME LOW POPS AND ISOLATED SHSN FOR THIS AS WV IS SHOWING A COUPLE
OF WAVES MOVING ACROSS SRN CANADA THAT ARE PROVIDING ENOUGH LIFT
TO GENERATE SOME LIGHT SNOW. EXPECT NO MORE THAN A COUPLE OF
TENTHS OF AN INCH OF FLUFF ACROSS THE FAR NORTH...AND RATHER
SPOTTY IN NATURE. SOUTHERN ZONES WILL BE MORE CHALLENGING AS SAT
TRENDS DO NOT GIVE ME A LOT OF CONFIDENCE THAT THE SRN VALLEY WILL
SEE CLOUDS MOVE IN...AND IF IT REMAINS CLEAR COULD BE WARMER THAN
FCST HIGHS.
TONIGHT...AN ARCTIC AIRMASS WILL BEGIN SINKING SOUTH AND THE DRIER
AIR SHOULD HELP CLEAR THINGS OUT AT LEAST IN THE NORTH. WILL SEE A
LARGE TEMP GRADIENT ACROSS CWA FROM NW TO SE AS LINGERING CLOUDS
IN THE FAR SE COULD KEEP OVERNIGHT LOWS IN THE LOW TEENS WHEREAS
THE NW SHOULD SEE TEMPS FALL INTO DOUBLE DIGITS BELOW ZERO AS THE
COLD AIRMASS DROPS INTO THE REGION.
SUNDAY...ARCTIC AIR MASS SINKING SOUTH WILL BRING AN INCREASE IN
SOLAR BUT MUCH COLDER AND DRIER AIR. DAYTIME HIGHS WILL STRUGGLE
TO RECOVER TO ABOVE ZERO TEMPS ACROSS THE NORTH...WHILE THE
SOUTHERN ZONES WILL LIKELY SEE EARLY HIGHS AS EARLY MORNING CLOUDS
KEEP SAT NIGHT LOWS IN THE MID TEENS PRIOR TO COLDER AIR MAKING IT
TO THE SOUTHERN ZONES. SHOULD SEE STEADY TO FALLING TEMPS IN THE AFTN.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 402 AM CST SAT DEC 27 2014
SUNDAY NIGHT THROUGH MONDAY NIGHT...SFC HIGH WILL MOVE OVER MT AND
DAKOTAS AND MN SHOULD SEE LIGHT NW FLOW...WHICH WILL KEEP MON
NIGHT LOWS FROM PLUMMETING TOO FAR BUT DOUBLE DIGITS BELOW ZERO
TEMPS ARE EXPECTED. ADDITIONALLY THE LIGHT NW WINDS WILL BE
SUFFICIENT TO BRING WIND CHILLS TO ADVISORY LEVELS BOTH MON AND
TUE MORNING. THE COLD APPARENT TEMPS BOTH MORNINGS WILL BE THE
MOST SIGNIFICANT WX HAZARD WITHIN THE SHORT TERM PERIOD.
WEDNESDAY THROUGH SATURDAY...THE DEEP LONG WAVE TROF OVER CENTRAL NOAM
EARLY IN THE WEEK SHOWS A DISTINCT SHIFT INTO THE EAST AT MIDWEEK
AND A RETURN TO A MORE ZONAL FLOW PATTERN ACROSS THE NORTHERN
PLAINS BY THE LATE WEEK PERIOD. EXPECT ARCTIC AIRMASS TO MODERATE
TO NEAR SEASONAL NORMALS WED INTO FRI...WITH AN ADDITIONAL SHOT OF
COLD AIR MOVING IN BY THE WEEK END. PRECIPITATION CHANCES ARE LOW
THROUGH THE PERIOD WITH OCCASIONAL LIGHT SNOW OR FLURRIES
POSSIBLE LATE THURSDAY INTO SATURDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 710 AM CST SAT DEC 27 2014
MVFR CIGS WILL PERSIST THROUGH THE DAY IN NORTHWEST AND W CNTRL
MN...WHILE VFR CIGS MOVE ACROSS EASTERN ND. MOS GUIDANCE
INDICATING THOSE CIGS LOWERING INTO MVFR RANGE...BUT WILL HOLD OFF
UNTIL SFC WINDS SHIFT TO NORTH THIS EVENING AND LOWER CIGS OVER
SRN MB BEGIN ADVECTING SOUTH. FAR WILL BE CLEAR FOR MUCH OF THE
MORNING BEFORE VFR DECK ARRIVES IN THE LATE MORNING. DVL/TVF/GFK
MAY SEE SOME LIGHT FLURRIES THROUGH MID AFTN...BUT NO REDUCTIONS
TO VSBY EXPECTED.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...SPEICHER
SHORT TERM...SPEICHER
LONG TERM...GUST/SPEICHER
AVIATION...SPEICHER
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
1101 AM EST SAT DEC 27 2014
.SYNOPSIS...
A COLD FRONT WILL PUSH ACROSS THE REGION TONIGHT BRINGING A CHANCE
OF PRECIPITATION TODAY INTO SUNDAY. HIGH PRESSURE WILL BRING
COOLER MORE SEASONABLE TEMPERATURES TO REGION FOR THE FIRST PART
OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
CONFIDENCE IN COVERAGE AND TIMING OF PRECIPITATION IS FAIRLY
LOW...UTILIZING HRRR SOLUTION FOR NOW WHICH DOES DEPICT THE LULL
AND SLOWER TIMING OF PRECIP ONSET WITH THE SECOND WAVE LATE THIS
AFTERNOON. WHILE SHOWERS NOT YET DEVELOPING TO OUR WEST AND
SW...STILL ANTICIPATION OF ISENTROPIC LIFT AHEAD OF THE FRONT TO
GENERATE SCATTERED AND THEN MORE WIDESPREAD COVERAGE AFTER 18Z.
HAVE RAISED TEMPS SLIGHTLY WITH THE WAA AND THE BREAK IN THE
RAINFALL.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/...
AS CDFNT PUSHES ACROSS THE FA TONIGHT WILL KEEP MENTION OF
CATEGORICAL POPS. COLDER AIR WORKING IN ON THE BACKSIDE OF THE
SYSTEM WILL CAUSE SOME SNOW TO MIX IN LATE TONIGHT INTO SUNDAY
MORNING.
WHILE INITIAL ENERGY MOVES THROUGH THE GREAT LAKES...THE
REMAINDER OF THE UPPER TROF WILL SLOWLY EJECT OUT OF ROCKIES. THIS
CAUSES THE FRONT AND THE BACK EDGE OF THE PCPN TO HANG UP FOR
SUNDAY. KEPT LIKELY POPS SE OF 71 FOR SUNDAY MORNING...WITH THE
EXTREME NW COUNTIES BEING DRY. SHEARED OUT TROF SWINGS THROUGH ON
SUNDAY FINALLY PULLING THE PCPN OUT OF THE REGION BY SUNDAY
EVENING.
HIGH PRESSURE WILL TRY AND NOSE IN FROM THE NORTH SUNDAY NIGHT
INTO MONDAY. A MODEL OR TWO IS HINTING AT SOME SPOTTY PCPN IN THE
CAA MONDAY. THINK THIS IS OVERDONE...SO LEFT THE FORECAST DRY FOR NOW.
TEMPERATURES WILL REMAIN ABOVE FREEZING TONIGHT...RANGING FROM THE
MID 30S INT HE NW TO THE MID 40S IN THE SE. TEMPERATURE WILL ONLY
RECOVER A FEW DEGREES ON SUNDAY AS THE COOLER AIR WORKS IN.
TEMPERATURES WILL BE MORE SEASONAL ON MONDAY WITH HIGHS IN THE MID
30S TO LOWER 40S.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
ANOTHER SHORTWAVE WILL ROTATE THROUGH THE GREAT LAKES MONDAY
NIGHT AND TUESDAY. THIS FEATURE WILL PUSH A SURFACE COLD FRONT
THROUGH THE AREA ON TUESDAY...THOUGH A RELATIVELY DRY AIRMASS WILL
PRECLUDE MUCH IN THE WAY OF PRECIPITATION. ANYTHING THAT DOES
OCCUR SHOULD BE IN THE FORM OF LIGHT SNOW SHOWERS OR A MIXTURE OF
LIGHT RAIN AND SNOW SHOWERS.
WEDNESDAY AND THURSDAY ARE EXPECTED TO BE DRY...WITH NEAR TO
SLIGHTLY BELOW NORMAL TEMPERATURES ACROSS THE AREA. THE SOUTHWEST
TROUGH IS PROGGED TO EJECT INTO THE WESTERN PLAINS STATES AT THE END
OF THE WEEK...RESULTING IN AN INCREASING CHANCE FOR PRECIPITATION
ACROSS THE OHIO VALLEY ON FRIDAY.
&&
.AVIATION /16Z SATURDAY THROUGH WEDNESDAY/...
SHORT RANGE MODELS CONTINUE TO SHOW THE BAND OF SHOWERS THAT WILL
PUSH INTO TAF SITES DISSIPATING THIS MORNING. WAS NOT SURE OF THE
VERACITY OF THESE MODELS BUT EVEN WITH THE LINE OF SHOWERS HOLDING
TOGETHER IT WOULD ONLY CONSTITUTE A 2 HOUR OR SO BLOCK OF TIME
WITH SHOWER ACTIVITY FROM A VFR CLOUD DECK. THE WORST OF THIS
MORNINGS ROUND OF SHOWERS WOULD DROP CIGS/VSBYS TO THE HIGHER END
OF MVFR AND THEN COME BACK UP TO VFR UNTIL THE NEXT ROUND OCCURS
AHEAD OF THE COLD FRONT. COLD FRONT WILL SWITCH WINDS TO NW AND
THEN N OVERNIGHT...WITH FROPA HAPPENING TOWARDS OR A LITTLE AFTER
MIDNIGHT TONIGHT.
LOWER MVFR AND SOME IFR CIGS ARE EXPECTED TONIGHT AS THE AMOUNT OF
AVAILABLE MOISTURE INCREASES AND SHOWERS BECOME MORE NUMEROUS
AHEAD OF THE FRONT THIS LATE DAY AND EVENING. RAIN WILL END NW-SE
ON SUNDAY AND CIGS WILL LIFT SOMEWHAT THROUGH THE DAY.
OUTLOOK...MVFR CIGS AND VSBYS POSSIBLE THROUGH EARLY SUNDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...SITES
NEAR TERM...JDR
SHORT TERM...SITES
LONG TERM...SHOBE2
AVIATION...FRANKS
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
850 AM EST SAT DEC 27 2014
.SYNOPSIS...
HIGH PRESSURE WILL MOVE OFF THE CAROLINA COAST TODAY AS A COLD FRONT
APPROACHES FROM THE WEST. EXPECT TEMPERATURES TO BE A FEW DEGREES
ABOVE NORMAL THIS WEEKEND. THE FRONT WILL CROSS MONDAY WITH A
SECONDARY FRONT PASSING IN MID WEEK DROPPING TEMPERATURES TO BELOW
NORMAL. THE NEXT COLD FRONT WILL ARRIVE AT THE END OF NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
845AM EST UPDATE...THE LATEST REGIONAL RADARS SHOW AREAS OF LIGHT
RETURNS OVER PORTIONS OF NE GA AND THE EXTREME WESTERN NC MTNS AS OF
THIS MORNING...IN LIGHT OF A WEAK UPPER DISTURBANCE LIFTING NE
ACROSS THE WESTERN ZONES OF THE CWA. ALSO...AREAS OF LIGHT PRECIP
CURRENTLY OVER AL AND PORTIONS OF NW GA WILL MOVE
EASTWARD...REACHING NE GA AND SW MTNS BY AROUND 18Z TODAY.
HOWEVER...LATEST HRRR SUGGESTS THIS FEATURE WILL WEAKEN AS IT ENTERS
OUR CWA ATT. HENCE...SLIGHT CHANCE TO THE LOW END CHANCE POPS WERE
WARRANTED THERE THROUGH THE MORNING HOURS INTO EARLY PART OF THIS
AFTERNOON. WITH TEMPS WARMING UP ABOVE THE FREEZING LEVEL...SHRA WAS
MENTIONED IN THE WX GRID.
AS OF 630 AM...LIGHT RETURNS ON REGIONAL 88DS ARE BEGINNING TO LIFT
NE OF THE AREA. THERE WAS ACTUALLY A LITTLE LIGHT SLEET REPORTED
UNDERNEATH SOME OF THIS ACTIVITY ACROSS THE MTNS EARLIER...WHICH IS
SURPRISING CONSIDERING THE VERY DRY SUBCLOUD LAYER (WITH CLOUDS
BASES AT AROUND 10 KFT). WITH RADAR EHCOES DIMINISHING...WILL
CONTINUE TO FEATURE A PRECIPITATION-LESS FORECAST THIS MORNING.
TEMPS SHOULD WARM TO AROUND 50 ACROSS THE PIEDMONT/FHILLS AND MTN
VALLEYS BY LATE MORNING.
A LOW AMPLITUDE RIDGE WILL PERSIST ALONG THE EAST COAST TODAY...
BEFORE MOVING OFF THE COAST BY THE END OF THE PERIOD...AS AN
UPSTREAM TROUGH BEGINS TO EJECT FROM TEXAS/THE SOUTHERN PLAINS.
TODAY WILL SEE A VARYING DEGREE OF MID/HIGH LEVEL CLOUD COVER ACROSS
THE WESTERN CAROLINAS AND NORTHEAST GEORGIA...RESULTING IN PARTLY
CLOUDY SKIES ACROSS MUCH OF THE AREA. MAX TEMPS WILL AVERAGE AROUND
10 DEGREES ABOVE CLIMO.
RAIN CHANCES INCREASE TONIGHT...AS A WEAK FRONTAL ZONE AND
ASSOCIATED WEAK LOW PRESSURE MOVE ACROSS THE TENN VALLEY. RESULTANT
ISENTROPIC LIFT/LOW LEVEL CONVERGENCE AND WEAK MID-LEVEL SHORT WAVE
TROUGH SHOULD SUPPORT RAIN MOVING INTO THE WESTERN ZONES BY MIDNIGHT
OR SO. RAIN CHANCES DIMINISH TOWARD THE SOUTHEAST...AS THE BEST
FORCING IS EXPECTED TO LIFT NORTHEAST ACROSS THE CWA BETWEEN 06 AND
12Z. POPS WILL RANGE FROM CATEGORICAL ACROSS THE MOUNTAINS/NC
FOOTHILLS/NORTHWEST UPSTATE...TO THE LOW END OF LIKELY ACROSS THE
SOUTHEAST ZONES. RAINFALL AMOUNTS THROUGH 12Z SHOULD RANGE FROM A
QUARTER TO HALF INCH ACROSS THE MOUNTAINS AND ADJACENT FOOTHILLS...
TO LESS THAN A QUARTER INCH ACROSS MUCH OF THE PIEDMONT. MIN TEMPS
WILL BE WELL ABOVE NORMAL.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 300 AM SAT...ON SUNDAY THE FAIRLY BROAD FRONTAL ZONE WILL
EXTEND FROM QUEBEC SWWD TO THE WRN GULF COAST...BISECTING THE TENN
VALLEY JUST TO OUR WEST. AT LEAST ONE WEAK WAVE IS PROGGED TO RIDE UP
THE FRONT DURING THE DAY AS A RESULT OF CYCLONIC UPPER FLOW OVER THE
BOUNDARY CONTAINING EMBEDDED WEAK VORTICES. THOUGH SUCH A WAVE WOULD
LIKELY PROVIDE LOCAL ENHANCEMENT TO LLVL WARM/MOIST ADVECTION AHEAD
OF THE FRONT...THE EXISTENCE OF ONE IS IN QUESTION GIVEN THE POOR
AGREEMENT AND CONSISTENCY FROM GUIDANCE ON HOW THIS OCCURS. OVERALL
THE FORCING SUNDAY IS JUST NOT ALL THAT IMPRESSIVE. LITTLE TO NO
INSTABILITY IS PROGGED OVER THE CWFA AND THOUGH A GOOD SLUG OF
MOISTURE TRANSPORT IS PRESENT ON NAM/GFS PROGS THE LLVL LIFT IS
LIMITED. AT ANY RATE...THRU SUNDAY THE FRONT REMAINS NEARLY
STATIONARY ACRS THE SOUTHEAST...THE PARENT LOW CONTINUING TO PROGRESS
EWD WITH THE ACTIVE NRN STREAM WHILE THE BROAD SRN STREAM TROUGH IS
HELD OFF BY THE BERMUDA HIGH. IT APPEARS THE FRONT WILL NOT ACTUALLY
ENTER THE AREA UNTIL MONDAY MRNG...WITH A DISTINCT 500MB SHORTWAVE
ACCOMPANYING IT AS WELL AS UPPER DIVERGENCE ASSOC WITH RR QUAD OF A
JET STREAK.
TWO PEAKS OF PRECIP ACTIVITY ARE SUGGESTED WHEN THE TOTAL FORCING IS
MAXIMIZED...SUNDAY MRNG AND THEN EARLY MON MRNG. HOWEVER IT IS
DIFFICULT TO PICK OUT A POINT BETWEEN WHERE A LULL SHOULD BE
BETWEEN...WITH THE OVERALL PATTERN REMAINING FAVORABLE FOR AT LEAST
LIGHT PRECIP. WILL CONTINUE TO ADVERTISE LIKELY POPS MOST OF THE AREA
THROUGHOUT SUNDAY...BUT CONCENTRATING MORE QPF CLOSE TO THE
AFOREMENTIONED PEAKS. DESPITE CLOUDS AND RAIN...IN THE WARM AIRMASS
TEMPS SHOULD TOP OUT 5-9 DEGREES ABOVE NORMAL SUN AFTN...WITH MINS
MON MRNG BEING EVEN MORE ABOVE NORMAL...UPPER 40S AND LOWER 50S. MAX
TEMPS MONDAY WILL BE SLIGHTLY WARMER THAN SUNDAY OVER THE PIEDMONT
WITH THE FRONT NOT YET HAVING AN IMPACT.
PROGRESSION OF THE UPPER PATTERN IS STILL PRETTY SLOW THRU MON
NIGHT...WITH THE CWFA NEAR THE INFLECTION POINT BETWEEN THE PLAINS
TROUGH AND THE ATLANTIC RIDGE. POPS DECLINE ONLY GRADUALLY THRU THE
END OF THE PERIOD WITH MOST OF THE GUIDANCE INDICATING SOME QPF
CONTINUING ON THE BACK SIDE OF ANOTHER FRONTAL WAVE DEVELOPING NEAR
THE GA/SC COAST. COLDER AIR WILL BEGIN TO RETURN TO ALL AREAS ON THE
ENSUING NLY FLOW MON NIGHT...THOUGH MIN TEMPS WILL STILL BE AROUND 10
DEGREES ABOVE CLIMO.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 200 AM SAT...QUASI-ZONAL UPPER FLOW CONTINUES OVER THE SUN BELT
TUESDAY EVEN AS A POLAR TROUGH MOVES INTO THE CONUS AND SHEARS INTO
TWO SHORTWAVES TO OUR NORTH AND WEST. ONE WAVE MOVES OVER THE GREAT
LAKES AND CONTRIBUTES TO GENTLE HEIGHT FALLS OVER THE SOUTHEAST
MID-WEEK...WHILE THE OTHER CUTS OFF OVER THE SOUTHWEST AND LEADS TO
THE DEVELOPMENT OF A SFC LOW OVER THE SRN PLAINS OR ARKLATEX BY THE
END OF THE WEEK. CONFLUENCE DOWNSTREAM OF THE SW TROUGH WILL PRODUCE
A SPRAWLING SFC HIGH WHICH WILL SPREAD ACRS THE OH VALLEY AND SRN
STATES TUE NIGHT THRU FRI. THIS WILL BRING SEASONABLY COOL CONDITIONS
FOR OUR AREA WITH TEMPS A SHADE BELOW CLIMO. MOST OF THE PERIOD LOOKS
DRY BEFORE POPS START RAMPING UP THU NIGHT AHEAD OF THE DEVELOPING
LOW.
&&
.AVIATION /14Z SATURDAY THROUGH WEDNESDAY/...
AT KCLT AND ELSEWHERE...HIGH/MID LEVEL CLOUDS OF VARYING DEGREES OF
THICKNESS AND COVERAGE WILL PASS OVER THE REGION THROUGHOUT THE
DAY...WITH CLOUD HEIGHTS EXPECTED TO BE AROUND 10 KFT OR HIGHER.
CIGS WILL DEVELOP/LOWER THIS EVENING...AS A COLD FRONT AND
ASSOCIATED WEAK LOW PRESSURE APPROACH FROM THE WEST. THIS IS
EXPECTED TO BRING -RA AND MVFR CIGS TO MOST OF THE TAF SITES BY THE
END OF THE PERIOD. WINDS WILL BE LIGHT THROUGH THE PERIOD...
GENERALLY FAVORING A SW DIRECTION THIS AFTERNOON/EVENING.
OUTLOOK...PERIODS OF RAIN AND FLIGHT RESTRICTIONS ARE EXPECTED
THROUGHOUT SUNDAY...MONDAY...AND MONDAY NIGHT BEFORE GRADUAL
IMPROVEMENT OCCURS THROUGHOUT TUESDAY. DRY HIGH PRESSURE SHOULD
RETURN BY MID-WEEK.
CONFIDENCE TABLE...
14-20Z 20-02Z 02-08Z 08-12Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 100% HIGH 100% HIGH 100% MED 73%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 100% HIGH 100% MED 64%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY
EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS
ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...DEO
NEAR TERM...JDL/JOH
SHORT TERM...WIMBERLEY
LONG TERM...ARK/WIMBERLEY
AVIATION...JDL
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
845 AM EST SAT DEC 27 2014
.SYNOPSIS...
HIGH PRESSURE WILL MOVE OFF THE CAROLINA COAST TODAY AS A COLD FRONT
APPROACHES FROM THE WEST. EXPECT TEMPERATURES TO BE A FEW DEGREES
ABOVE NORMAL THIS WEEKEND. THE FRONT WILL CROSS MONDAY WITH A
SECONDARY FRONT PASSING IN MID WEEK DROPPING TEMPERATURES TO BELOW
NORMAL. THE NEXT COLD FRONT WILL ARRIVE AT THE END OF NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
845AM EST UPDATE...THE LATEST REGIONAL RADARS SHOWING AREAS OF LIGHT
RETURNS OVER PORTIONS OF NE GA AND SW NC MTNS AS OF THIS
MORNING...IN LIGHT OF A WEAK UPPER DISTURBANCE LIFTING NE ACROSS THE
WESTERN ZONES OF THE CWA. ALSO...AREAS OF LIGHT PRECIP CURRENTLY
OVER AL AND PORTIONS OF NW GA WILL MOVE EASTWARD...REACHING NE GA
AND SW MTNS BY AROUND 18Z TODAY. HOWEVER...LATEST HRRR SUGGESTS THIS
FEATURE WILL WEAKEN AS IT ENTERS OUR CWA ATT. HENCE...SLIGHT CHANCE
TO THE LOW END CHANCE POPS WERE WARRANTED THERE THROUGH THE MORNING
HOURS INTO EARLY PART OF THIS AFTERNOON. WITH TEMPS WARMING UP ABOVE
THE FREEZING LEVEL...SHRA WAS MENTIONED IN THE WX GRID.
AS OF 630 AM...LIGHT RETURNS ON REGIONAL 88DS ARE BEGINNING TO LIFT
NE OF THE AREA. THERE WAS ACTUALLY A LITTLE LIGHT SLEET REPORTED
UNDERNEATH SOME OF THIS ACTIVITY ACROSS THE MTNS EARLIER...WHICH IS
SURPRISING CONSIDERING THE VERY DRY SUBCLOUD LAYER (WITH CLOUDS
BASES AT AROUND 10 KFT). WITH RADAR EHCOES DIMINISHING...WILL
CONTINUE TO FEATURE A PRECIPITATION-LESS FORECAST THIS MORNING.
TEMPS SHOULD WARM TO AROUND 50 ACROSS THE PIEDMONT/FHILLS AND MTN
VALLEYS BY LATE MORNING.
A LOW AMPLITUDE RIDGE WILL PERSIST ALONG THE EAST COAST TODAY...
BEFORE MOVING OFF THE COAST BY THE END OF THE PERIOD...AS AN
UPSTREAM TROUGH BEGINS TO EJECT FROM TEXAS/THE SOUTHERN PLAINS.
TODAY WILL SEE A VARYING DEGREE OF MID/HIGH LEVEL CLOUD COVER ACROSS
THE WESTERN CAROLINAS AND NORTHEAST GEORGIA...RESULTING IN PARTLY
CLOUDY SKIES ACROSS MUCH OF THE AREA. MAX TEMPS WILL AVERAGE AROUND
10 DEGREES ABOVE CLIMO.
RAIN CHANCES INCREASE TONIGHT...AS A WEAK FRONTAL ZONE AND
ASSOCIATED WEAK LOW PRESSURE MOVE ACROSS THE TENN VALLEY. RESULTANT
ISENTROPIC LIFT/LOW LEVEL CONVERGENCE AND WEAK MID-LEVEL SHORT WAVE
TROUGH SHOULD SUPPORT RAIN MOVING INTO THE WESTERN ZONES BY MIDNIGHT
OR SO. RAIN CHANCES DIMINISH TOWARD THE SOUTHEAST...AS THE BEST
FORCING IS EXPECTED TO LIFT NORTHEAST ACROSS THE CWA BETWEEN 06 AND
12Z. POPS WILL RANGE FROM CATEGORICAL ACROSS THE MOUNTAINS/NC
FOOTHILLS/NORTHWEST UPSTATE...TO THE LOW END OF LIKELY ACROSS THE
SOUTHEAST ZONES. RAINFALL AMOUNTS THROUGH 12Z SHOULD RANGE FROM A
QUARTER TO HALF INCH ACROSS THE MOUNTAINS AND ADJACENT FOOTHILLS...
TO LESS THAN A QUARTER INCH ACROSS MUCH OF THE PIEDMONT. MIN TEMPS
WILL BE WELL ABOVE NORMAL.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 300 AM SAT...ON SUNDAY THE FAIRLY BROAD FRONTAL ZONE WILL
EXTEND FROM QUEBEC SWWD TO THE WRN GULF COAST...BISECTING THE TENN
VALLEY JUST TO OUR WEST. AT LEAST ONE WEAK WAVE IS PROGGED TO RIDE UP
THE FRONT DURING THE DAY AS A RESULT OF CYCLONIC UPPER FLOW OVER THE
BOUNDARY CONTAINING EMBEDDED WEAK VORTICES. THOUGH SUCH A WAVE WOULD
LIKELY PROVIDE LOCAL ENHANCEMENT TO LLVL WARM/MOIST ADVECTION AHEAD
OF THE FRONT...THE EXISTENCE OF ONE IS IN QUESTION GIVEN THE POOR
AGREEMENT AND CONSISTENCY FROM GUIDANCE ON HOW THIS OCCURS. OVERALL
THE FORCING SUNDAY IS JUST NOT ALL THAT IMPRESSIVE. LITTLE TO NO
INSTABILITY IS PROGGED OVER THE CWFA AND THOUGH A GOOD SLUG OF
MOISTURE TRANSPORT IS PRESENT ON NAM/GFS PROGS THE LLVL LIFT IS
LIMITED. AT ANY RATE...THRU SUNDAY THE FRONT REMAINS NEARLY
STATIONARY ACRS THE SOUTHEAST...THE PARENT LOW CONTINUING TO PROGRESS
EWD WITH THE ACTIVE NRN STREAM WHILE THE BROAD SRN STREAM TROUGH IS
HELD OFF BY THE BERMUDA HIGH. IT APPEARS THE FRONT WILL NOT ACTUALLY
ENTER THE AREA UNTIL MONDAY MRNG...WITH A DISTINCT 500MB SHORTWAVE
ACCOMPANYING IT AS WELL AS UPPER DIVERGENCE ASSOC WITH RR QUAD OF A
JET STREAK.
TWO PEAKS OF PRECIP ACTIVITY ARE SUGGESTED WHEN THE TOTAL FORCING IS
MAXIMIZED...SUNDAY MRNG AND THEN EARLY MON MRNG. HOWEVER IT IS
DIFFICULT TO PICK OUT A POINT BETWEEN WHERE A LULL SHOULD BE
BETWEEN...WITH THE OVERALL PATTERN REMAINING FAVORABLE FOR AT LEAST
LIGHT PRECIP. WILL CONTINUE TO ADVERTISE LIKELY POPS MOST OF THE AREA
THROUGHOUT SUNDAY...BUT CONCENTRATING MORE QPF CLOSE TO THE
AFOREMENTIONED PEAKS. DESPITE CLOUDS AND RAIN...IN THE WARM AIRMASS
TEMPS SHOULD TOP OUT 5-9 DEGREES ABOVE NORMAL SUN AFTN...WITH MINS
MON MRNG BEING EVEN MORE ABOVE NORMAL...UPPER 40S AND LOWER 50S. MAX
TEMPS MONDAY WILL BE SLIGHTLY WARMER THAN SUNDAY OVER THE PIEDMONT
WITH THE FRONT NOT YET HAVING AN IMPACT.
PROGRESSION OF THE UPPER PATTERN IS STILL PRETTY SLOW THRU MON
NIGHT...WITH THE CWFA NEAR THE INFLECTION POINT BETWEEN THE PLAINS
TROUGH AND THE ATLANTIC RIDGE. POPS DECLINE ONLY GRADUALLY THRU THE
END OF THE PERIOD WITH MOST OF THE GUIDANCE INDICATING SOME QPF
CONTINUING ON THE BACK SIDE OF ANOTHER FRONTAL WAVE DEVELOPING NEAR
THE GA/SC COAST. COLDER AIR WILL BEGIN TO RETURN TO ALL AREAS ON THE
ENSUING NLY FLOW MON NIGHT...THOUGH MIN TEMPS WILL STILL BE AROUND 10
DEGREES ABOVE CLIMO.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 200 AM SAT...QUASI-ZONAL UPPER FLOW CONTINUES OVER THE SUN BELT
TUESDAY EVEN AS A POLAR TROUGH MOVES INTO THE CONUS AND SHEARS INTO
TWO SHORTWAVES TO OUR NORTH AND WEST. ONE WAVE MOVES OVER THE GREAT
LAKES AND CONTRIBUTES TO GENTLE HEIGHT FALLS OVER THE SOUTHEAST
MID-WEEK...WHILE THE OTHER CUTS OFF OVER THE SOUTHWEST AND LEADS TO
THE DEVELOPMENT OF A SFC LOW OVER THE SRN PLAINS OR ARKLATEX BY THE
END OF THE WEEK. CONFLUENCE DOWNSTREAM OF THE SW TROUGH WILL PRODUCE
A SPRAWLING SFC HIGH WHICH WILL SPREAD ACRS THE OH VALLEY AND SRN
STATES TUE NIGHT THRU FRI. THIS WILL BRING SEASONABLY COOL CONDITIONS
FOR OUR AREA WITH TEMPS A SHADE BELOW CLIMO. MOST OF THE PERIOD LOOKS
DRY BEFORE POPS START RAMPING UP THU NIGHT AHEAD OF THE DEVELOPING
LOW.
&&
.AVIATION /14Z SATURDAY THROUGH WEDNESDAY/...
AT KCLT AND ELSEWHERE...HIGH/MID LEVEL CLOUDS OF VARYING DEGREES OF
THICKNESS AND COVERAGE WILL PASS OVER THE REGION THROUGHOUT THE
DAY...WITH CLOUD HEIGHTS EXPECTED TO BE AROUND 10 KFT OR HIGHER.
CIGS WILL DEVELOP/LOWER THIS EVENING...AS A COLD FRONT AND
ASSOCIATED WEAK LOW PRESSURE APPROACH FROM THE WEST. THIS IS
EXPECTED TO BRING -RA AND MVFR CIGS TO MOST OF THE TAF SITES BY THE
END OF THE PERIOD. WINDS WILL BE LIGHT THROUGH THE PERIOD...
GENERALLY FAVORING A SW DIRECTION THIS AFTERNOON/EVENING.
OUTLOOK...PERIODS OF RAIN AND FLIGHT RESTRICTIONS ARE EXPECTED
THROUGHOUT SUNDAY...MONDAY...AND MONDAY NIGHT BEFORE GRADUAL
IMPROVEMENT OCCURS THROUGHOUT TUESDAY. DRY HIGH PRESSURE SHOULD
RETURN BY MID-WEEK.
CONFIDENCE TABLE...
13-19Z 19-01Z 01-07Z 07-12Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 100% HIGH 100% HIGH 100% MED 78%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 100% HIGH 100% MED 67%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY
EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS
ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...DEO
NEAR TERM...JDL/JOH
SHORT TERM...WIMBERLEY
LONG TERM...ARK/WIMBERLEY
AVIATION...JDL
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
634 AM EST SAT DEC 27 2014
.SYNOPSIS...
HIGH PRESSURE WILL MOVE OFF THE CAROLINA COAST TODAY AS A COLD FRONT
APPROACHES FROM THE WEST. EXPECT TEMPERATURES TO BE A FEW DEGREES
ABOVE NORMAL THIS WEEKEND. THE FRONT WILL CROSS MONDAY WITH A
SECONDARY FRONT PASSING IN MID WEEK DROPPING TEMPERATURES TO BELOW
NORMAL. THE NEXT COLD FRONT WILL ARRIVE AT THE END OF NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM...LIGHT RETURNS ON REGIONAL 88DS ARE BEGINNING TO LIFT
NE OF THE AREA. THERE WAS ACTUALLY A LITTLE LIGHT SLEET REPORTED
UNDERNEATH SOME OF THIS ACTIVITY ACROSS THE MTNS EARLIER...WHICH IS
SURPRISING CONSIDERING THE VERY DRY SUBCLOUD LAYER (WITH CLOUDS
BASES AT AROUND 10 KFT). WITH RADAR EHCOES DIMINISHING...WILL
CONTINUE TO FEATURE A PRECIPITATION-LESS FORECAST THIS MORNING.
TEMPS SHOULD WARM TO AROUND 50 ACROSS THE PIEDMONT/FHILLS AND MTN
VALLEYS BY LATE MORNING.
A LOW AMPLITUDE RIDGE WILL PERSIST ALONG THE EAST COAST TODAY...
BEFORE MOVING OFF THE COAST BY THE END OF THE PERIOD...AS AN
UPSTREAM TROUGH BEGINS TO EJECT FROM TEXAS/THE SOUTHERN PLAINS.
TODAY WILL SEE A VARYING DEGREE OF MID/HIGH LEVEL CLOUD COVER ACROSS
THE WESTERN CAROLINAS AND NORTHEAST GEORGIA...RESULTING IN PARTLY
CLOUDY SKIES ACROSS MUCH OF THE AREA. MAX TEMPS WILL AVERAGE AROUND
10 DEGREES ABOVE CLIMO.
RAIN CHANCES INCREASE TONIGHT...AS A WEAK FRONTAL ZONE AND
ASSOCIATED WEAK LOW PRESSURE MOVE ACROSS THE TENN VALLEY. RESULTANT
ISENTROPIC LIFT/LOW LEVEL CONVERGENCE AND WEAK MID-LEVEL SHORT WAVE
TROUGH SHOULD SUPPORT RAIN MOVING INTO THE WESTERN ZONES BY MIDNIGHT
OR SO. RAIN CHANCES DIMINISH TOWARD THE SOUTHEAST...AS THE BEST
FORCING IS EXPECTED TO LIFT NORTHEAST ACROSS THE CWA BETWEEN 06 AND
12Z. POPS WILL RANGE FROM CATEGORICAL ACROSS THE MOUNTAINS/NC
FOOTHILLS/NORTHWEST UPSTATE...TO THE LOW END OF LIKELY ACROSS THE
SOUTHEAST ZONES. RAINFALL AMOUNTS THROUGH 12Z SHOULD RANGE FROM A
QUARTER TO HALF INCH ACROSS THE MOUNTAINS AND ADJACENT FOOTHILLS...
TO LESS THAN A QUARTER INCH ACROSS MUCH OF THE PIEDMONT. MIN TEMPS
WILL BE WELL ABOVE NORMAL.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 300 AM SAT...ON SUNDAY THE FAIRLY BROAD FRONTAL ZONE WILL
EXTEND FROM QUEBEC SWWD TO THE WRN GULF COAST...BISECTING THE TENN
VALLEY JUST TO OUR WEST. AT LEAST ONE WEAK WAVE IS PROGGED TO RIDE UP
THE FRONT DURING THE DAY AS A RESULT OF CYCLONIC UPPER FLOW OVER THE
BOUNDARY CONTAINING EMBEDDED WEAK VORTICES. THOUGH SUCH A WAVE WOULD
LIKELY PROVIDE LOCAL ENHANCEMENT TO LLVL WARM/MOIST ADVECTION AHEAD
OF THE FRONT...THE EXISTENCE OF ONE IS IN QUESTION GIVEN THE POOR
AGREEMENT AND CONSISTENCY FROM GUIDANCE ON HOW THIS OCCURS. OVERALL
THE FORCING SUNDAY IS JUST NOT ALL THAT IMPRESSIVE. LITTLE TO NO
INSTABILITY IS PROGGED OVER THE CWFA AND THOUGH A GOOD SLUG OF
MOISTURE TRANSPORT IS PRESENT ON NAM/GFS PROGS THE LLVL LIFT IS
LIMITED. AT ANY RATE...THRU SUNDAY THE FRONT REMAINS NEARLY
STATIONARY ACRS THE SOUTHEAST...THE PARENT LOW CONTINUING TO PROGRESS
EWD WITH THE ACTIVE NRN STREAM WHILE THE BROAD SRN STREAM TROUGH IS
HELD OFF BY THE BERMUDA HIGH. IT APPEARS THE FRONT WILL NOT ACTUALLY
ENTER THE AREA UNTIL MONDAY MRNG...WITH A DISTINCT 500MB SHORTWAVE
ACCOMPANYING IT AS WELL AS UPPER DIVERGENCE ASSOC WITH RR QUAD OF A
JET STREAK.
TWO PEAKS OF PRECIP ACTIVITY ARE SUGGESTED WHEN THE TOTAL FORCING IS
MAXIMIZED...SUNDAY MRNG AND THEN EARLY MON MRNG. HOWEVER IT IS
DIFFICULT TO PICK OUT A POINT BETWEEN WHERE A LULL SHOULD BE
BETWEEN...WITH THE OVERALL PATTERN REMAINING FAVORABLE FOR AT LEAST
LIGHT PRECIP. WILL CONTINUE TO ADVERTISE LIKELY POPS MOST OF THE AREA
THROUGHOUT SUNDAY...BUT CONCENTRATING MORE QPF CLOSE TO THE
AFOREMENTIONED PEAKS. DESPITE CLOUDS AND RAIN...IN THE WARM AIRMASS
TEMPS SHOULD TOP OUT 5-9 DEGREES ABOVE NORMAL SUN AFTN...WITH MINS
MON MRNG BEING EVEN MORE ABOVE NORMAL...UPPER 40S AND LOWER 50S. MAX
TEMPS MONDAY WILL BE SLIGHTLY WARMER THAN SUNDAY OVER THE PIEDMONT
WITH THE FRONT NOT YET HAVING AN IMPACT.
PROGRESSION OF THE UPPER PATTERN IS STILL PRETTY SLOW THRU MON
NIGHT...WITH THE CWFA NEAR THE INFLECTION POINT BETWEEN THE PLAINS
TROUGH AND THE ATLANTIC RIDGE. POPS DECLINE ONLY GRADUALLY THRU THE
END OF THE PERIOD WITH MOST OF THE GUIDANCE INDICATING SOME QPF
CONTINUING ON THE BACK SIDE OF ANOTHER FRONTAL WAVE DEVELOPING NEAR
THE GA/SC COAST. COLDER AIR WILL BEGIN TO RETURN TO ALL AREAS ON THE
ENSUING NLY FLOW MON NIGHT...THOUGH MIN TEMPS WILL STILL BE AROUND 10
DEGREES ABOVE CLIMO.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 200 AM SAT...QUASI-ZONAL UPPER FLOW CONTINUES OVER THE SUN BELT
TUESDAY EVEN AS A POLAR TROUGH MOVES INTO THE CONUS AND SHEARS INTO
TWO SHORTWAVES TO OUR NORTH AND WEST. ONE WAVE MOVES OVER THE GREAT
LAKES AND CONTRIBUTES TO GENTLE HEIGHT FALLS OVER THE SOUTHEAST
MID-WEEK...WHILE THE OTHER CUTS OFF OVER THE SOUTHWEST AND LEADS TO
THE DEVELOPMENT OF A SFC LOW OVER THE SRN PLAINS OR ARKLATEX BY THE
END OF THE WEEK. CONFLUENCE DOWNSTREAM OF THE SW TROUGH WILL PRODUCE
A SPRAWLING SFC HIGH WHICH WILL SPREAD ACRS THE OH VALLEY AND SRN
STATES TUE NIGHT THRU FRI. THIS WILL BRING SEASONABLY COOL CONDITIONS
FOR OUR AREA WITH TEMPS A SHADE BELOW CLIMO. MOST OF THE PERIOD LOOKS
DRY BEFORE POPS START RAMPING UP THU NIGHT AHEAD OF THE DEVELOPING
LOW.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
AT KCLT AND ELSEWHERE...HIGH/MID LEVEL CLOUDS OF VARYING DEGREES OF
THICKNESS AND COVERAGE WILL PASS OVER THE REGION THROUGHOUT THE
DAY...WITH CLOUD HEIGHTS EXPECTED TO BE AROUND 10 KFT OR HIGHER.
CIGS WILL DEVELOP/LOWER THIS EVENING...AS A COLD FRONT AND
ASSOCIATED WEAK LOW PRESSURE APPROACH FROM THE WEST. THIS IS
EXPECTED TO BRING -RA AND MVFR CIGS TO MOST OF THE TAF SITES BY THE
END OF THE PERIOD. WINDS WILL BE LIGHT THROUGH THE PERIOD...
GENERALLY FAVORING A SW DIRECTION THIS AFTERNOON/EVENING.
OUTLOOK...PERIODS OF RAIN AND FLIGHT RESTRICTIONS ARE EXPECTED
THROUGHOUT SUNDAY...MONDAY...AND MONDAY NIGHT BEFORE GRADUAL
IMPROVEMENT OCCURS THROUGHOUT TUESDAY. DRY HIGH PRESSURE SHOULD
RETURN BY MID-WEEK.
CONFIDENCE TABLE...
11-17Z 17-23Z 23-05Z 05-06Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 100% HIGH 100% HIGH 100% MED 60%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 100% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY
EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS
ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...DEO
NEAR TERM...JDL
SHORT TERM...WIMBERLEY
LONG TERM...ARK/WIMBERLEY
AVIATION...JDL
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
724 AM CST SAT DEC 27 2014
.UPDATE...
HAVE UPDATED TO INCLUDE A RAIN/SLEET/SNOW MIX WEST OF A SHERMAN TO
WEATHERFORD TO COMANCHE LINE FOR THE REMAINDER OF THE DAY. RECENT
REPORTS FROM AREAS JUST WEST OF THE CWA INDICATE SOME LIGHT SNOW AND
SLEET IS OCCURRING. FORECAST SOUNDINGS...IN PARTICULAR THE
RAP...SUPPORT SOME LIGHT SNOW AND/OR SLEET MAY OCCUR WITH THE RAIN
TODAY ACROSS THE WEST AND NORTHWEST. VERY LITTLE SNOW OR SLEET
ACCUMULATIONS MAY OCCUR ON ELEVATED OR METAL SURFACES AND ROADWAYS
ARE EXPECTED TO REMAIN CLEAR OF ANY SNOW OR SLEET. ALSO ADJUSTED
POPS UP FOR THE MORNING HOURS BASED ON LATEST RADAR TRENDS. UPDATED
HOURLY TEMPERATURE FORECASTS AND WIND TRENDS FOR THE REMAINDER OF
THE DAY AS WELL USING THE LATEST RAP DATA. THE FRONT HAS JUST
ABOUT PUSHED THROUGH THE ENTIRE CWA AS OF 725 AM.
82/JLD
&&
.AVIATION...
/ISSUED 553 AM CST SAT DEC 27 2014/
A COLD FRONT HAD MOVED THROUGH ALL TAF SITES AS OF 530 AM. THE
PASSAGE OF THE FRONT BROUGHT DRIER AIR AND LIFTING CEILINGS. MVFR
CONDITIONS WILL PREVAIL THROUGH SUNRISE WITH CEILINGS LIFTING
ABOVE 3000 FT BY MID TO LATE MORNING. SCATTERED LIGHT SHOWERS ARE
POSSIBLE THROUGH THE MORNING BUT THE BETTER RAIN CHANCES WILL
ARRIVE THIS AFTERNOON AS LARGE SCALE LIFT ASSOCIATED WITH A
APPROACHING UPPER TROUGH INCREASES. ANY SHOWERS THAT DEVELOP THIS
AFTERNOON WILL BE RELATIVELY LIGHT BUT MAY BE ACCOMPANIED BY MVFR
CEILINGS. A FEW SHOWERS COULD LINGER OVERNIGHT BUT COVERAGE WILL
BE TOO LIMITED TO INCLUDE IN THIS FORECAST. VFR CONDITIONS WILL PREVAIL
TONIGHT WITH SCATTERED TO BROKEN MIDDLE AND UPPER LEVEL CLOUDS.
A NORTH WIND WILL PREVAIL BETWEEN 16 AND 20 KNOTS TODAY WITH SOME
GUSTS UP TO ABOUT 27 KNOTS. WIND SPEEDS SHOULD FALL BELOW 15 KNOTS
BY MID EVENING.
79
&&
.PREV DISCUSSION... /ISSUED 442 AM CST SAT DEC 27 2014/
THE FIRST OF THREE COLD FRONTS THAT WILL AFFECT THE REGION OVER
THE NEXT 7-8 DAYS IS CURRENTLY MOVING THROUGH NORTH CENTRAL TEXAS.
AT 320 AM...THE FRONT WAS ROUGHLY ALONG A LINE FROM PARIS TO
DALLAS TO GOLDTHWAITE. AROUND MID MORNING...THE FRONT WILL HAVE
TRAVERSED OUR ENTIRE CWA...MOVING SOUTH AND SOUTHEAST. TEMPERATURES
BEHIND THE FRONT HAVE FALLEN INTO THE 40S WHILE TEMPERATURES AHEAD
OF THE FRONT REMAIN IN THE 60S. MOST LOCATIONS WILL EXPERIENCE
THEIR DAYTIME HIGHS NEAR DAYBREAK WITH SLOWLY FALLING TEMPERATURES
THROUGHOUT THE DAY. HOWEVER...AFTERNOON TEMPERATURES ACROSS OUR
NORTHWESTERN COUNTIES WILL LIKELY REMAIN NEARLY STEADY...POSSIBLY
CREEPING UP A DEGREE OR TWO...BEFORE BEGINNING TO FALL AGAIN AROUND
SUNSET THIS EVENING. THE REGION WILL REMAIN OVERCAST/CLOUDY TODAY
WITH SOME CLEARING ACROSS THE WEST THIS EVENING AND TONIGHT.
HOWEVER...HIGH CLOUDS WILL BEGIN MOVING IN FROM THE WEST WHICH
CREATES A CHALLENGE FOR OVERNIGHT LOWS. THE HIGH CLOUD COVER
SHOULD KEEP OVERNIGHT LOWS FROM FULLY FALLING AS MUCH AS THEY
WOULD UNDER CLEARER SKIES...BUT STILL EXPECT A MUCH COLDER NIGHT
WITH OVERNIGHT LOWS IN THE UPPER 20S NORTHWEST TO UPPER 30S IN THE
SOUTHEAST WHERE DENSE CLOUD COVER WILL PREVAIL.
ONGOING SHOWERS THIS MORNING WILL CONTINUE THROUGH THE DAY AS LIFT
FROM AN UPPER LEVEL TROUGH TO OUR WEST CONTINUES ACROSS THE
REGION. WHILE THERE COULD BE A FEW RUMBLES OF THUNDER AT
TIMES...HAVE LEFT THE THUNDER MENTION OUT OF THE FORECAST FOR NOW
AS THE ELEVATED INSTABILITY IS PRETTY MINIMAL. MOST OF THE AREA
WILL RECEIVE LESS THAN A QUARTER OF AN INCH OF RAIN TODAY...WITH
SOME ISOLATED HIGHER AMOUNTS. MOST THE PRECIPITATION WILL END THIS
EVENING BUT SOME ADDITIONAL SHOWERS MAY OCCUR SUNDAY MORNING
ACROSS OUR SOUTHERN COUNTIES AS THE UPPER LEVEL TROUGH SWINGS
THROUGH THE REGION. WE WILL SEE WARMING TEMPERATURES SUNDAY
THROUGH MONDAY AS WE AWAIT OUR NEXT SYSTEM.
THE NEXT SYSTEM CONTINUES TO BE A DEEPENING TROUGH OVER THE WEST
COAST NEXT WEEK. THIS TROUGH IS CURRENTLY LOCATED OFF THE COAST
OF BRITISH COLUMBIA AND WILL CONTINUE A SOUTHWARD TRACK FOR THE
NEXT SEVERAL DAYS. AS THIS TROUGH DEVELOPS...IT WILL MAINTAIN A
BROAD LATITUDINAL ORIENTATION OR POSITIVE TILT...WHICH RESULTS IN
NEAR ZONAL FLOW ACROSS A GOOD MAJORITY OF THE COUNTRY. THIS
ORIENTATION WILL ALLOW COLD ARCTIC AIR AT THE SURFACE TO RUSH OUT
OF CANADA...INTO THE PLAINS...AND DOWN THROUGH TEXAS. THE ARCTIC
FRONT SHOULD NOT MEET MUCH RESISTANCE MOVING SOUTH AND IS EXPECTED
TO ARRIVE HERE MONDAY NIGHT/TUESDAY MORNING. THE FRONT IS NOT
EXPECTED TO QUICKLY AND AGGRESSIVELY MOVE THROUGH THE REGION...BUT
WILL INSTEAD GRADUALLY SPREAD ACROSS THE REGION WITH NOTICEABLY
COLDER TEMPERATURES BEHIND THE FRONT. THE 1055 MB PLUS SURFACE
HIGH BEHIND THE FRONT WILL TAKE A FEW DAYS TO MOVE INTO THE
SOUTHERN PLAINS...MEANING THE COLD WEATHER WILL BE AROUND FOR A
FEW DAYS. ON TUESDAY...HIGHS WILL RANGE FROM THE MID 30S IN THE
NORTHWEST TO LOWER 50S IN THE SOUTHEAST. HIGH TEMPERATURES ON
WEDNESDAY WILL ONLY BE IN THE 30S AND LOWER 40S...WITH THE
NORTHWEST STRUGGLING TO REACH ABOVE FREEZING. LOW TEMPERATURES
TUESDAY AND WEDNESDAY NIGHTS WILL BE IN THE 20S AND 30S.
STRENGTHENING WARM AIR ADVECTION WILL ACTUALLY WARM OVERNIGHT
TEMPERATURES WEDNESDAY NIGHT/THURSDAY MORNING BUT LOWS THAT NIGHT
WILL STILL BE IN THE 20S AND 30S...AND HIGHS ON THURSDAY WILL
REMAIN IN THE 30S AND LOWER 40S DUE TO CLOUD COVER AND RAIN.
OUR MAIN CONCERN AND CHALLENGE WITH THIS SYSTEM IS THE POTENTIAL
FOR PRECIPITATION AND ESPECIALLY FROZEN PRECIPITATION. THE UPPER
LEVEL TROUGH WILL CUT OFF INTO A LOW OVER CALIFORNIA ON WEDNESDAY.
WHEN AN UPPER LEVEL LOW CUTS OFF...IT BECOMES SEPARATED FROM THE
MAIN JET STREAM AND WILL TEND TO SLOW DOWN ITS TREK AS A RESULT.
THIS IS INDICATED IN THE MODELS AS THE LOW SLOWS DOWN AND REMAINS
OVER THE SOUTHWESTERN CONUS THROUGH FRIDAY. WITH THE UPPER LEVEL
LOW WELL TO OUR WEST...TEXAS REMAINS IN A NEARLY ZONAL AND/OR
SLIGHTLY RIDGED PATTERN ALOFT. IN THIS PATTERN...THERE IS GENERALLY
A LACK OF LARGE SCALE LIFT ACROSS THE REGION SO WE HAVE TO LOOK
CLOSER AT SMALLER SCALE FEATURES FOR ANY LIFT FOR PRECIPITATION
DEVELOPMENT.
THE FRONT IS EXPECTED TO COME THROUGH DRY AND THE MODELS HAVE
CONSISTENTLY INDICATED NO PRECIPITATION ALONG THE FRONT.
HOWEVER...AS AN H850 HIGH MOVES INTO THE REGION TUESDAY NIGHT AND
WEDNESDAY...IT TURNS THE 850 MB WINDS ACROSS OUR SOUTHWESTERN AND
WESTERN COUNTIES TO THE SOUTH WHICH RESULTS IN SOME WEAK WARM AIR
ADVECTION OVER THE COLD SURFACE LAYER. DO NOT THINK THE WARM AIR
ADVECTION WILL BE STRONG ENOUGH TO GENERATE MUCH PRECIPITATION BUT
THERE IS STILL A SMALL CHANCE IT COULD DEVELOP SOME LIGHT
PRECIPITATION AND WILL RETAIN THE LOW POPS IN THE SOUTHWEST
TUESDAY NIGHT AND IN THE WEST WEDNESDAY WITH A MENTION OF LIGHT
DRIZZLE/FREEZING DRIZZLE. CONFIDENCE IS LOW THIS WILL OCCUR...BUT
IF IT DOES...VERY LIGHT ACCUMULATIONS OF ICE MAY OCCUR ON ELEVATED
SURFACES...WINDSHIELDS...AND POSSIBLY TREE BRANCHES. WE ARE
TRYING TO ANTICIPATE SMALLER SCALE FEATURES SEVERAL DAYS IN
ADVANCE WHICH IS DIFFICULT TO DO...SO WE WANT TO EMPHASIS THAT THE
CHANCES FOR FROZEN PRECIPITATION REMAIN LOW AND WILL CONTINUE TO
MONITOR THIS TIME PERIOD IN FUTURE FORECAST RUNS.
BETTER PRECIPITATION CHANCES ARE EXPECTED THURSDAY THROUGH FRIDAY
AS THE UPPER LEVEL LOW BEGINS MOVING EAST AND INCREASES LIFT
ACROSS THE REGION. WARM AIR ADVECTION AND ISENTROPIC LIFT WILL
START TO INCREASE LATE WEDNESDAY NIGHT AND THURSDAY
MORNING...CONTINUING THROUGH THE DAY ON THURSDAY. IN THIS
REGIME...PRECIPITATION WILL LIKELY DEVELOP FROM SOUTH TO NORTH
ACROSS THE REGION. EVEN THOUGH TEMPERATURES WILL LIKELY BE RISING
FOR PART OF THE NIGHT...THERE WILL STILL BE A PERIOD WHERE
TEMPERATURES WILL BE SLIGHTLY BELOW FREEZING ACROSS OUR WESTERN
COUNTIES AND THESE AREAS COULD SEE LIGHT FREEZING RAIN FOR A FEW
HOURS. IMPACTS SHOULD BE VERY MINIMAL DURING THE PERIOD OF
FREEZING RAIN AS TEMPERATURES ARE EXPECTED TO BE IN THE LOWER 30S
AND FREEZING RAIN USUALLY DOES NOT START TO HAVE A SIGNIFICANT
IMPACT...ESPECIALLY ON ROADS...UNLESS TEMPERATURES ARE IN THE
UPPER 20S. HOWEVER...WE WILL HAVE TO MONITOR CHANGES TO THE
TEMPERATURE FORECAST THAT NIGHT. BUT WITH INCREASING TEMPERATURES
THROUGH THE NIGHT...THE WARMING TEMPERATURES AND CHANGEOVER TO
LIQUID RAIN WILL ACT TO MELT ANY ICE LATER IN THE NIGHT.
A COLD...BUT ALL LIQUID...RAIN IS EXPECTED TO BE MORE WIDESPREAD
THURSDAY THROUGH FRIDAY. HAVE INCREASED POPS IN THIS TIME FRAME
WITH THE MODEL QPF INDICATING SOME BENEFICIAL RAIN IS POSSIBLE.
THERE COULD BE TWO ROUNDS OF RAIN DURING THIS TIME...ONE ON
THURSDAY AND ANOTHER ON FRIDAY. ANOTHER COLD FRONT IS POSSIBLE
FRIDAY OR SATURDAY.
82/JLD
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 45 32 50 33 58 / 60 20 5 5 5
WACO, TX 49 34 49 32 61 / 60 20 10 5 5
PARIS, TX 50 33 49 32 55 / 60 30 5 5 5
DENTON, TX 42 29 50 32 57 / 60 20 5 5 5
MCKINNEY, TX 45 31 49 32 57 / 60 20 5 5 5
DALLAS, TX 46 33 50 34 59 / 60 20 5 5 5
TERRELL, TX 52 34 50 32 58 / 60 30 5 5 5
CORSICANA, TX 54 35 49 33 60 / 60 30 10 5 5
TEMPLE, TX 51 34 49 32 61 / 50 20 20 5 5
MINERAL WELLS, TX 42 28 49 31 58 / 60 10 5 5 5
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
79/82
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
337 PM CST SAT DEC 27 2014
.SHORT TERM...
307 PM CST
REMAINDER OF THIS AFTERNOON AND TONIGHT...
A STRONG COLD FRONT IS TRACKING ACROSS THE REGION...USHERING IN MUCH
COOLER AIR ALONG WITH SOME SCT LIGHT PCPN. AS OF 230PM CDT...THE
SFC FRONTAL BOUNDARY EXTENDED FROM WESTERN LOWER MICHIGAN...TO
EAST-CENTRAL IL...TO SERN MO. WINDS HAVE BEEN GUSTING TO ARND 30
MPH FOLLOWING THE FROPA WHILE VEERING FROM SWLY TO WLY.
TEMPERATURES ARE SLOWLY DROPPING OFF WITH THE FROPA AND THE BULK OF
THE PCPN IS POST-FRONTAL AS A STRONG LOW LEVEL JET HAS SET UP ALONG
AN ELEVATED BAROCLINIC ZONE. SOME SCT RAIN IS STILL POSSIBLE OVER
NWRN IN AND ECNTRL IL AHEAD OF THE FRONT...BUT AS COOLER AIR FILTERS
IN BEHIND THE BOUNDARY...LIQUID PCPN IN THE POST-SFC FRONTAL
BOUNDARY SHOULD TRANSITION INTO A MIX OF RAIN...SNOW AND POSSIBLE
SOME GRAPPLE. THE SHARPER TEMPERATURE DROPOFF WILL OCCUR LATER THIS
AFTERNOON AND THROUGH THIS EVENING AS A SECONDARY TROUGH ASSOCIATED
WITH A SURGE OF COOLER AIR PUSHED ACROSS THE EVENING WHICH WILL BE
ACCOMPANIED BY A WIND SHIFT TO WLY-WNWLY. ANY LINGERING PCPN SHOULD
PUSH END OVER NWRN IL-ECNTRL IL DURG THE LATE EVENING HOURS AND
TEMPERATURES OVERNIGHT SHOULD RANGE FROM ARND 20F OVER THE ROCKFORD
AREA TO THE UPPER 20S EAST OF THE I-55 CORRIDOR.
KREIN
&&
.LONG TERM...
307 PM CST
SUNDAY THROUGH SATURDAY...
THE PASSAGE OF THE SYSTEM CURRENTLY MOVING THROUGH THE REGION IS A
SIGNAL OF A MAJOR PATTERN SHIFT FROM THE UNSEASONABLY WARM
CONDITIONS OF RECENT DAYS BACK TO MORE SEASONABLE CONDITIONS AS THE
SHORT-WAVELENGTH...HIGH AMPLITUDE TROUGH SHEARS OUT INTO BROAD WEAK
TROUGHING ALOFT THROUGH THE REMAINDER OF THE WEEKEND. THE GENERAL
TEMPERATURE TREND FOR SUNDAY AND INTO EARLY NEXT WEEK WILL BE FOR A
SLOW COOLING TREND UNDER BROAD...WEAK HEIGHT FALLS ALOFT. A
STRONGER SURGE OF COLD AIR WITH A SERIES OF NRN STREAM SHORTWAVES
WILL USHER IN THE TRUE COLD AIR BY MONDAY NIGHT AND TUESDAY WITH
TEMPERATURES MONDAY MORNING DROPPING OFF INTO THE LOWER TEENS OVER
THE ROCKFORD AREA TO AROUND 20F EAST OF THE I-55 CORRIDOR. THE
UPPER LEVEL PATTERN WILL SET UP TO MORE ZONAL OVER THE SRN CONUS
AS THE MAIN JET PATTERN SHIFTS TO THE SOUTH WHILE POLAR-SOURCED
SHORT WAVE ENERGY DROPS INTO THE UPPER MISSISSIPPI VALLEY AND
THROUGH THE MIDWEST AND GREAT LAKES REGIONS THROUGH THE REMAINDER OF
NEXT WEEK. THE LARGE SCALE PATTERN WILL ALSO BECOME LESS
PROGRESSIVE...WITH THE LONGER RANGE GUIDANCE INDICATING A CUT OFF
LOW DIGGING INTO SRN CALIFORNIA AND VERY SLOWLY TRACKING EWD THROUGH
THE DESERT SOUTHWEST BY LATE NEXT WEEK WHILE SUB-TROPICAL HIGH
PRESSURE REMAINS PARKED OVER THE WESTERN CARIBBEAN AND GREATER
ANTILLES. THE SLOWING PROGRESSION TO THE LONGWAVE PATTERN WILL IN
TURN SET UP A PERIOD WITH A SERIES OF NRN STREAM SHORTWAVES KEEPING
A STEADY STREAM OF SEASONABLY COLD AIR INTO THE REGION. THE NEXT
CHANCE FOR ANY PCPN ACROSS THE AREA WILL BE MONDAY AFTERNOON INTO
TUESDAY AS A COLD FRONT ON THE LEADING EDGE OF AN ARCTIC AIRMASS
TRIES TO SQUEEZE OUT A LITTLE SNOW IN A RELATIVELY DRY ENVIRONMENT.
LITTLE OR NO ACCUMULATION IS EXPECTED OVER MUCH OF THE AREA...
PERHAPS A DUSTING WITH SCT SNOW SHOWERS. HOWEVER...AS SFC HIGH
PRESSURE BUILDS ACROSS THE UPPER MISSISSIPPI VALLEY AND INTO THE
GREAT LAKES REGIONS...A PERIOD OF GENERALLY NORTHERLY FLOW WILL SET
UP OVER LAKE MICHIGAN...AND THERE WILL BE A CHANCE FOR SOME LAKE
EFFECT SNOW INITIALLY ALONG THE ILLINOIS LAKE MICHIGAN SHORE MONDAY
EVENING AND THEN GRADUALLY TRANSITIONING TO THE EAST OVER NWRN
INDIANA MONDAY NIGHT INTO TUESDAY MORNING AS FLOW BACKS MORE NWLY.
IT IS STILL A LITTLE EARLY TO DISCUSS ACCUMULATIONS WITH LAKE EFFECT
SNOW AT THIS POINT...BUT HAVE INCREASED POPS TO LIKELY FOR THE
FAVORED LAKE EFFECT AREAS AND WOULD ANTICIPATE SOME MEASURABLE
ACCUMULATION. MIDWEEK SHOULD BE DRY...BUT WITH THE LOWEST
TEMPERATURES OF THE PERIOD AS THE SFC HIGH PRESSURE SETTLES INTO THE
LOWER MISSISSIPPI VALLEY AND SERN CONUS. BY LATE NEXT WEEK...THE
LONGER RANGE GUIDANCE IS INDICATING THAT THE CUT OFF LOW DROPPING
INTO THE DESERT SOUTHWEST WILL FINALLY BEGIN TO LIFT OUT TO THE
NORTHEAST WHILE A NRN STREAM SHORTWAVE DROPS THROUGH THE NRN PLAINS
TO THE UPPER MISSISSIPPI VALLEY. HOWEVER...WHILE THE LONGER RANGE
GUIDANCE IS IN RELATIVELY DECENT AGREEMENT ON THE TREND...THERE ARE
CONSIDERABLE DIFFERENCES IN THE TIMING WITH THE GFS MUCH FASTER THAN
THE ECMWF OR GEM. GIVEN THAT SOUTHWEST CUT-OFF LOWS TEND TO LINGER
LONGER THAN THE MODELS LIKE TO FORECAST...HAVE TRENDED THE LONGER
TERM FORECAST CLOSER TO THE SLOWER SOLUTIONS...AND WOULD NOT BE
SURPRISED TO SEE THE MODELS TREND EVEN SLOWER THAN CURRENTLY
INDICATED. SO...WILL LIMIT POPS TO CHANCE LEVELS WITH TEMPERATURES
CONDUCIVE TO SNOW FOR NOW.
KREIN
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* WEST WINDS GUSTING ARND 25 KT THROUGH THE AFTN.
* MVFR CIGS PERSISTING THROUGH THE EVENING.
JEE
//DISCUSSION...UPDATED 18Z...
THE COLD FRONT EXTENDS FROM PWK THROUGH FORD COUNTY IL AND IT WILL
CONTINUE EAST WITH 30KT GUSTS ALONG THE FRONT. SCATTERED LIGHT
SHOWERS ARE ALONG THE FRONT AND STILL NOT EXPECTING ANY
SIGNIFICANT IMPACT FROM THEM AS THEY QUICKLY SHIFT EAST OF THE
TERMINALS. IFR CIGS LIFT TO MVFR BEHIND THE FRONT AS WELL.
VFR CONDITIONS EXTEND FROM CENTRAL MN THROUGH NE AND EXPECTING
CIGS TO SCATTER OUT OVERNIGHT. HIGH PRESSURE SPREADS IN AND NW
WINDS DIMINISH TO LESS THAN 20 KT OVERNIGHT. VERY WEAK
WINDS...LESS THAN 5 KT...VARY FROM WEST OR SOUTHWEST OVER RFD
TOMORROW TO NORTHWEST TO NORTH OVER THE EASTERN TERMINALS.
JEE
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE IN CIG TRENDS...MEDIUM CONFIDENCE IN TIMING.
* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
JEE
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT...VFR.
MONDAY...CHANCE OF -SN OR FLURRIES...ESPECIALLY AT NIGHT. MVFR
CIGS LIKELY.
TUESDAY THROUGH FRIDAY...PREDOMINANTLY VFR.
IZZI
&&
.MARINE...
336 PM CST
AS LOW PRESSURE CONTINUES TO LIFT NORTHEAST THROUGH THE CENTRAL
GREAT LAKES THIS AFTERNOON...A COLD FRONT WILL PUSH THROUGH THE
REMAINING AREAS OVER THE LAKE. ON THE BACKSIDE OF THIS SYSTEM AND
WITH THE ARRIVAL OF MUCH COLDER AIR OVER THE WATER...A ONE TO
THREE HOUR WINDOW OF GALES/GUSTS DID OCCUR THIS PAST AFTERNOON
OVER MUCH OF THE LAKE. THE PEAK OF THESE HIGHEST GUSTS HAS ALREADY
OCCURRED AND EXPECT A DOWNWARD TREND IN SPEEDS FROM THIS POINT
FORWARD. NONETHELESS...A BRIEF GALE FORCE GUST CANT BE RULED OUT
HERE IN THE VERY NEAR TERM. A WEST NORTHWEST WIND CAN BE EXPECTED
FOR THE REMAINDER OF THE NIGHT...AS WINDS DIMINISH AND WAVES
SUBSIDE. A PERIOD OF NORTHERLY WINDS WILL BE OBSERVED OVER THE
ENTIRE LAKE THROUGH EARLY NEXT WEEK...AS HIGH PRESSURE BUILDS
ACROSS THE REGION.
RODRIGUEZ
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 4 AM SUNDAY.
SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO GARY IN UNTIL 10 PM
SATURDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
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WWW.YOUTUBE.COM/NWSCHICAGO
[top]
Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
313 PM CST Sat Dec 27 2014
.SHORT TERM...(Tonight)
ISSUED AT 313 PM CST SAT DEC 27 2014
Low clouds, drizzle, light rain showers still ongoing across the
forecast area this afternoon. Cold front about out of ILX
area...just NW of Lawrenceville. Some flakes mixing into the precip
on the extreme NW edge of the post frontal echos on radar. Front
progression somewhat steady although running into more parallel flow
aloft. Cold dense air from the NW really colder behind the post
frontal precip spread across the radar mosaic. Timing of the cold
air a minor concern as time progresses. Ground temps still close to
40 degrees, but with the arrival of the freezing temps, some
elevated surfaces could develop some slick spots. The arrival of the
coldest air will be after the precip has come to an end...so
freezing should be confined to the residual moisture/puddles from
todays drizzle/rain. Another issue with the overnight forecast is
the cloud cover. GFS is quick to break it out...a little faster than
is currently represented on sat imagery. NAM is far cloudier,
trapping the moisture in the boundary layer and preventing the mix
out entirely. RUC looking more like the NAM with representing the
developing inversion behind the boundary. Plenty of dry air up
there, but how quickly it will erode through the clouds is a huge
question mark. Covered in cirrus all day, not convinced the diurnal
influence on the clouds is enough to erode them at sunset.
Considering how quickly sunset is approaching, going to split the
difference more or less with a slower clearing out...but not quite
as trapped as the NAM. Some breaking up could be seen in the far NW,
and forecast low temps are considerably cooler as a result.
However, going cloudier overall through the night.
&&
.LONG TERM...(Sunday through Saturday)
ISSUED AT 313 PM CST SAT DEC 27 2014
High pressure behind the front will bring dry weather to the area
for tomorrow through Monday. However, this mild high pressure area
will be temporary as a stronger/colder high pressure area drops into
the region Tuesday. A weak boundary will be between these two high
pressure areas, but it will have very little moisture to work with.
This will be an Arctic front with much colder air behind it. Any
precip with this Arctic front will be very light and could occur
Monday night. With the colder temps and limited moisture, only pcpn
expected will be flurries. Also believe this will be across the
northern 2/3rds of the CWA, leaving the southeastern CWA dry as the
area flurries moves east.
Temps will be around normal tomorrow and Monday, but then drop to
below normal for Tue as the Arctic cold high pressure moves in.
Cold, dry Arctic high pressure will dominate the area for days 3-5,
but as the high pressure modifies and moves into southeastern US,
temps will begin to warm gradually and a weather system will develop
in the southwestern US and begin to move out into the plains. With
high pressure to the east and a surface low pressure area to the
west, warmer air will not be the only thing to return to the area.
Moisture will also return and this will bring pcpn to the area as
the moisture interacts with a warm front and lifts northward into
the area. P-type could be very interesting and be dependent on the
surface temperature and temps in the lower levels. Models
forecasting temps above zero at 850mb over the area, which would
indicate rain. However, surface temps look to be below freezing Fri
night; and this could mean frozen pcpn possible. Considering Fri
through Sat is Day6-7, will not get too detailed on pcpn type and
just go with snow or rain, or a mix of rain and snow. Thinking
mostly rain on Friday with a mix in the north, then a mix becoming
all snow on Fri night, and then all snow in the east on Sat. Am
expecting the p-type to change over the next several days, and when
the event becomes better defined by the models and closer.
As mentioned earlier, temps will start cold and then gradually warm
during the week.
&&
.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
ISSUED AT 1135 AM CST SAT DEC 27 2014
Conditions behind the front improving to MVFR, and IFR still ahead
of the boundary. DEC in midst of fropa, and CMI to follow. Tempos
in to hold for lower cigs and lesser vis associated with the
front. Winds more westerly/northwesterly, but a more southwesterly
flow aloft. Major concern is the longevity of the lower clouds
behind the boundary. Where as the sfc boundary may race out ahead
the remaining llvl moisture may contribute to keeping the clouds
around a little longer than expected. Models not really picking up
on the current situation. All the weak returns out to the west and
SW also point to abundant moisture. Think the sky will eventually
scatter, though later than prev expected.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...HJS
LONG TERM...Auten
AVIATION...HJS
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
155 PM CST SAT DEC 27 2014
.SHORT TERM...
245 AM CST
THROUGH SUNDAY...
WE ARE LIVING ON BORROWED TIME WITH 850 MB TEMPS SITTING ABOVE
ZERO...BUT THAT WILL BE A THING OF THE PAST COME THIS AFTERNOON. BUT
FIRST OFF...LIGHT RAIN/DRIZZLE IN EAST CENTRAL ILLINOIS AND INTO NW
INDY IS ASSOCIATED WITH THE SLIGHTLY BETTER ISENTROPIC LIFT/MOISTURE
ADVECTION. THIS WILL DRIFT OFF TO THE EAST THIS MORNING AND WILL
GRAZE OUR SE COUNTIES. MEANWHILE A SECOND AREA OF LIGHT RAIN
CONTINUES OVER NORTHWEST/NORTH CENTRAL ILLINOIS CLOSER TO THE NORTHWARD
MOVING LOW AND EASTWARD ADVANCING COLD FRONT. MUCH OF OUR AREA FINDS
ITSELF IN AN AREA OF WEAKER ISENTROPIC LIFT AND A BIT REMOVED FROM
THE FRONTAL INFLUENCE. THEREFORE...EXPECT SCATTERED LIGHT
RAIN/DRIZZLE IN BETWEEN THAT SHOULD BE LESS ORGANIZED THAN THESE TWO
AREAS.
THE SURFACE LOW IN IOWA CONTINUES TO DEEPEN AND PUSH NE TO NORTHERN
LAKE MICHIGAN THIS MORNING. THE BETTER UPPER DYNAMICS WITH THE
FRONT ARE WITH THE SHORTWAVE MOVING THROUGH IOWA...AND THIS HEADS
NORTHWEST OF OUR AREA TODAY AS WELL. ENOUGH FRONTAL CONVERGENCE
EXISTS TO CARRY A LOW POP RAIN MENTION THROUGH THE MORNING THOUGH
MANY AREAS STAY DRY. THE BETTER MID LEVEL FORCING/FRONTOGENESIS
ARRIVES WITH THE FRONT THIS AFTERNOON BUT MOISTURE IS
LACKING...THEREFORE EXPECT A LARGELY DRY AFTERNOON EXCEPT IN NW
INDIANA AND EASTERN PORTIONS OF ILLINOIS. WITH A STRENGTHENING
UPPER JET OVERHEAD...EXPECT BREEZY SOUTHWEST WINDS AHEAD OF THE
FRONT...THEN GUSTY WEST WINDS BEHIND IT. AFTER A PLEASANT WARM UP
THE LAST FEW DAYS...THIS FRONT DOES HAVE SOME KICK TO IT...AND
WHILE THE COLD AIR DOES NOT NECESSARILY COME SCREAMING IN...DO
EXPECT A RETURN TO REALITY AND MORE SEASONAL CONDITIONS.
THE COLD FRONT WILL BE THROUGH TONIGHT. ANY LINGERING PRECIP IN OUR
FAR SE COUNTIES OF NW INDIANA MAY SEE A LIGHT RAIN/SNOW MIX BEFORE
PRECIP ENDS. OTHERWISE HIGH PRESSURE NOSES IN FROM THE WEST BRINGING
GRADUAL CLEARING OVERNIGHT. READINGS OVERNIGHT DROP INTO THE 20S
TO AROUND 30. SUNDAY LOOKS TO BE GENERALLY SUNNY BUT SEASONALLY
COLD AS THE MAIN UPPER LOW PASSES THROUGH SOUTHERN CANADA.
KMD
&&
.LONG TERM...
245 AM CST
SUNDAY NIGHT THROUGH FRIDAY...
STRONGER CANADIAN HIGH PRESSURE...WILL BE KNOCKING AT OUR DOOR ON
SUNDAY NIGHT...AND WILL SEND A WEAK BACK DOOR COLD FRONT DOWN THE
LAKE. THE LEADING EDGE OF THIS SECONDARY SURGE OF COLD AIR WILL
TRIGGER A SIGNIFICANTLY COLDER STRETCH OF WEATHER TO KICK OFF THE
LAST FEW DAYS OF 2014. THERE MAY BE SOME WEAK LAKE EFFECT SNOW
SHOWERS GETTING INTO NE ILLINOIS...OTHERWISE INCREASING CLOUDS AND
COLDER. THEN AS THE TRULY ARCTIC AIR SPILLS IN MONDAY NIGHT...WE MAY
SEE SOME SNOW SHOWERS ALONG THE BAROCLINIC ZONE. MOISTURE IS NOT
IMPRESSIVE WITH THE FRONT...BUT THE COMBINED NE FLOW OFF THE LAKE
WITH MORE SIGNIFICANT INVERSION HEIGHTS AND MUCH COLDER AIR MAY
ALLOW FOR LAKE ENHANCEMENT AND SOME BETTER ACCUMULATION POTENTIAL.
THEN THE CHILL ENSUES FOR SEVERAL DAYS OF HIGHS ON EITHER SIDE OF 20
AND LOWS IN THE SINGLE DIGITS AND TEENS AS WE REMAIN IN NW FLOW. THE
UPSIDE...LIKELY SOME MORE SUN TO ENJOY TO END THE YEAR...AS ANY
SHORTWAVE ENERGY ROTATING THROUGH FROM THE CANADIAN VORTEX WILL
EITHER REMAIN NORTH OR GENERALLY BE WEAK AS THE ONE THAT COMES
THROUGH TUESDAY NIGHT. SOME MODIFICATION TO THE COLD AIR MASS
ARRIVES ON NEW YEARS DAY AND MORE SO FRIDAY AS WE RETURN TO
SOUTHERLY FLOW. AS THIS OCCURS...WILL HAVE TO WATCH IF LOW
PRESSURE THAT CLOSES OFF OVER CALIFORNIA EARLIER IN THE WEEK
PHASES WITH THE NORTHERN STREAM LOW OR REMAINS FARTHER SOUTH AS
THIS WILL HAVE IMPLICATIONS FOR ANY PRECIPITATION CHANCES TOWARD
WEEKS END.
KMD
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* WEST WINDS GUSTING ARND 25 KT THROUGH THE AFTN.
* MVFR CIGS PERSISTING THROUGH THE EVENING.
JEE
//DISCUSSION...UPDATED 18Z...
THE COLD FRONT EXTENDS FROM PWK THROUGH FORD COUNTY IL AND IT WILL
CONTINUE EAST WITH 30KT GUSTS ALONG THE FRONT. SCATTERED LIGHT
SHOWERS ARE ALONG THE FRONT AND STILL NOT EXPECTING ANY
SIGNIFICANT IMPACT FROM THEM AS THEY QUICKLY SHIFT EAST OF THE
TERMINALS. IFR CIGS LIFT TO MVFR BEHIND THE FRONT AS WELL.
VFR CONDITIONS EXTEND FROM CENTRAL MN THROUGH NE AND EXPECTING
CIGS TO SCATTER OUT OVERNIGHT. HIGH PRESSURE SPREADS IN AND NW
WINDS DIMINISH TO LESS THAN 20 KT OVERNIGHT. VERY WEAK
WINDS...LESS THAN 5 KT...VARY FROM WEST OR SOUTHWEST OVER RFD
TOMORROW TO NORTHWEST TO NORTH OVER THE EASTERN TERMINALS.
JEE
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE IN CIG TRENDS...MEDIUM CONFIDENCE IN TIMING.
* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
JEE
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT...VFR.
MONDAY...CHANCE OF -SN OR FLURRIES...ESPECIALLY AT NIGHT. MVFR
CIGS LIKELY.
TUESDAY THROUGH FRIDAY...PREDOMINANTLY VFR.
IZZI
&&
.MARINE...
158 AM CST
LOW OVER EASTERN IOWA WILL QUICKLY DEEPEN THROUGH THIS EVENING
AS IT TRACKS NORTHEAST ACROSS NORTHERN LAKE MICHIGAN AND
EVENTUALLY OFF INTO QUEBEC. DUE TO THE BRIEF BUT RAPID DEEPENING
AND COLD AIR ADVECTION THIS AFTERNOON THERE COULD BE A VERY BRIEF
WINDOW OF GALES BEHIND THE FRONT FOR AN HOUR OR TWO OVER SOUTHERN
PORTIONS OF THE LAKE. DURATION LOOKS TO BE TOO SHORT FOR GALE
WARNING THOUGH SO NO HEADLINE PLANNED FOR OPEN WATERS. WINDS/WAVES
LOOK TO RAPIDLY SUBSIDE TONIGHT INTO MONDAY BEFORE AN ARCTIC FRONT
BEGINS WORKING SOUTH DOWN THE LAKE MONDAY NIGHT INTO TUESDAY.
TIGHT GRADIENT BEHIND THE FRONT ALONG WITH VERY COLD AIR AND
UNSTABLE CONDITIONS SHOULD ALLOW FOR STRONG NORTHERLIES TO
DEVELOP...POSSIBLY TO NEAR GALE FORCE BEHIND THE FRONT. THAT
SHOULD MARK THE START OF AN ACTIVE PERIOD ON THE LAKE WITH LOW
PRESSURE TRACKING ACROSS CANADA MIDWEEK DRAGGING A FRONT ACROSS
THE LAKE AND TIGHTENING THE PRESSURE GRADIENT AND PROBABLY LEADING
TO A PERIOD OF WESTERLY GALES WEDNESDAY/EARLY THURSDAY TIME FRAME.
IZZI
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 4 AM SUNDAY.
SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO GARY IN UNTIL 10 PM
SATURDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1142 AM CST Sat Dec 27 2014
.UPDATE...
ISSUED AT 1033 AM CST SAT DEC 27 2014
Weak cold front making its way through the state this morning and
has just passed over I-55 according to the depiction on radar and
the wind shift to more westerly in the obs. Cooler temps on the way
and a non-diurnal trend anticipated for locations behind the
front. Some minor precip along the boundary, but majority of radar
returns post-frontal not producing much in the way of measurable precip,
with the vast majority being drizzle. Only a few obs even picking
up on that. Not going to update the pops too much as the better
chances for rain remain in the southeast for the rest of the day.
Some small updates here and there, but nothing large scale. Will
reissue the zones only to refresh the morning wording closer to
noon.
&&
.SHORT TERM...(Today)
ISSUED AT 324 AM CST SAT DEC 27 2014
08z/2am surface analysis shows 1013mb low just north of KMLI, with
frontal boundary extending southwestward into Texas. Airmass ahead
of the front was initially quite dry as evidenced by the 00z KILX
upper air sounding: however, shallow low-level moisture has been on
the increase throughout the night. Surface dewpoints have reached
the middle 40s across central Illinois, while a plume of 50s
dewpoints is noted further upstream pushing into Arkansas. LAPS
soundings show this increasing moisture, with most local profiles
now saturated below 700mb. As low pressure tracks further
northeastward into Wisconsin, it will pull the cold front into the
area later this morning, then to the Indiana border by mid to late
afternoon. Continued moisture pooling along/ahead of the front
will result in increasingly deep moisture profiles, particularly
across the E/SE CWA this afternoon. HRRR suggests only scattered
light showers across much of the area this morning, then shows
more widespread precipitation developing along/east of I-57 this
afternoon. Think this solution makes sense as front gradually taps
into increasing amounts of Gulf moisture as it moves further east.
As a result, will carry chance PoPs across the western half of the
CWA throughout the day, with chance PoPs increasing to likely
across the E/SE this afternoon. With cold front passing through
the area, high temperatures will be achieved this morning,
followed by brisk westerly winds and falling temperatures later in
the day. Due to very mild current temps, have generally gone 2-4
degrees above MAV guidance numbers. End result will be highs in
the upper 40s and lower 50s, with temps dropping into the 30s
along/west of I-55 during the afternoon.
&&
.LONG TERM...(Tonight through Friday)
ISSUED AT 324 AM CST SAT DEC 27 2014
Cold front will slowly push eastward into the Ohio River Valley
tonight, with clouds and showers lingering across the E/SE through
at least the evening hours. NAM is fastest with the departure of
the precip, while GFS tends to keep it around through the entire
night. Based on slow forward movement of the front, have trended
toward the slower GFS. As a result, will maintain low chance PoPs
along/south of I-70 through the overnight hours. As temperatures
slowly fall into the lower to middle 30s across this area, any
lingering rain showers may mix with or change to light snow late.
Further northwest, skies will clear across the Illinois River
Valley, allowing lows to bottom out in the lower to middle 20s.
Sunshine and seasonably cool temps in the 30s will prevail Sunday
into Monday, before a surge of cold air arrives next week. Models
have been consistently showing strong 1050mb high building southward
out of western Canada into the central CONUS by Tuesday/Wednesday.
Weak synoptic lift along the leading edge of the cold air may be
enough to trigger a few flurries across the area Monday night, but
the main story will be the colder temps. High temps will remain in
the 20s Tuesday/Wednesday, while overnight lows dip into the single
digits and teens. After that, Canadian high pressure will gradually
slide east of the region, allowing a southern stream system to
approach by the end of the week. Model solutions vary with this
feature, so forecast confidence remains low at this point. ECMWF
aggressively brings precip northward into south-central Illinois as
early as Thursday night, while the GFS is about 12-18 hours
slower. Meanwhile, the GEM suggests the system may remain largely
southeast of the area across the Ohio River Valley. Given the
uncertainties, have opted to go with a dry forecast Thursday night,
and to slow precip onset on Friday. Have trimmed Friday PoPs to
just slight chance, with higher precip chances arriving Friday night
into Saturday. Think slower/colder is the way to go, especially
given the Canadian airmass that will initially be in place. End
result will be a chance of snow or a rain/snow mix mainly Friday
night into Saturday.
&&
.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
ISSUED AT 1135 AM CST SAT DEC 27 2014
Conditions behind the front improving to MVFR, and IFR still ahead
of the boundary. DEC in midst of fropa, and CMI to follow. Tempos
in to hold for lower cigs and lesser vis associated with the
front. Winds more westerly/northwesterly, but a more southwesterly
flow aloft. Major concern is the longevity of the lower clouds
behind the boundary. Where as the sfc boundary may race out ahead
the remaining llvl moisture may contribute to keeping the clouds
around a little longer than expected. Models not really picking up
on the current situation. All the weak returns out to the west and
SW also point to abundant moisture. Think the sky will eventually
scatter, though later than prev expected.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HJS
SHORT TERM...Barnes
LONG TERM...Barnes
AVIATION...HJS
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1115 AM CST SAT DEC 27 2014
.SHORT TERM...
245 AM CST
THROUGH SUNDAY...
WE ARE LIVING ON BORROWED TIME WITH 850 MB TEMPS SITTING ABOVE
ZERO...BUT THAT WILL BE A THING OF THE PAST COME THIS AFTERNOON. BUT
FIRST OFF...LIGHT RAIN/DRIZZLE IN EAST CENTRAL ILLINOIS AND INTO NW
INDY IS ASSOCIATED WITH THE SLIGHTLY BETTER ISENTROPIC LIFT/MOISTURE
ADVECTION. THIS WILL DRIFT OFF TO THE EAST THIS MORNING AND WILL
GRAZE OUR SE COUNTIES. MEANWHILE A SECOND AREA OF LIGHT RAIN
CONTINUES OVER NORTHWEST/NORTH CENTRAL ILLINOIS CLOSER TO THE NORTHWARD
MOVING LOW AND EASTWARD ADVANCING COLD FRONT. MUCH OF OUR AREA FINDS
ITSELF IN AN AREA OF WEAKER ISENTROPIC LIFT AND A BIT REMOVED FROM
THE FRONTAL INFLUENCE. THEREFORE...EXPECT SCATTERED LIGHT
RAIN/DRIZZLE IN BETWEEN THAT SHOULD BE LESS ORGANIZED THAN THESE TWO
AREAS.
THE SURFACE LOW IN IOWA CONTINUES TO DEEPEN AND PUSH NE TO NORTHERN
LAKE MICHIGAN THIS MORNING. THE BETTER UPPER DYNAMICS WITH THE
FRONT ARE WITH THE SHORTWAVE MOVING THROUGH IOWA...AND THIS HEADS
NORTHWEST OF OUR AREA TODAY AS WELL. ENOUGH FRONTAL CONVERGENCE
EXISTS TO CARRY A LOW POP RAIN MENTION THROUGH THE MORNING THOUGH
MANY AREAS STAY DRY. THE BETTER MID LEVEL FORCING/FRONTOGENESIS
ARRIVES WITH THE FRONT THIS AFTERNOON BUT MOISTURE IS
LACKING...THEREFORE EXPECT A LARGELY DRY AFTERNOON EXCEPT IN NW
INDIANA AND EASTERN PORTIONS OF ILLINOIS. WITH A STRENGTHENING
UPPER JET OVERHEAD...EXPECT BREEZY SOUTHWEST WINDS AHEAD OF THE
FRONT...THEN GUSTY WEST WINDS BEHIND IT. AFTER A PLEASANT WARM UP
THE LAST FEW DAYS...THIS FRONT DOES HAVE SOME KICK TO IT...AND
WHILE THE COLD AIR DOES NOT NECESSARILY COME SCREAMING IN...DO
EXPECT A RETURN TO REALITY AND MORE SEASONAL CONDITIONS.
THE COLD FRONT WILL BE THROUGH TONIGHT. ANY LINGERING PRECIP IN OUR
FAR SE COUNTIES OF NW INDIANA MAY SEE A LIGHT RAIN/SNOW MIX BEFORE
PRECIP ENDS. OTHERWISE HIGH PRESSURE NOSES IN FROM THE WEST BRINGING
GRADUAL CLEARING OVERNIGHT. READINGS OVERNIGHT DROP INTO THE 20S
TO AROUND 30. SUNDAY LOOKS TO BE GENERALLY SUNNY BUT SEASONALLY
COLD AS THE MAIN UPPER LOW PASSES THROUGH SOUTHERN CANADA.
KMD
&&
.LONG TERM...
245 AM CST
SUNDAY NIGHT THROUGH FRIDAY...
STRONGER CANADIAN HIGH PRESSURE...WILL BE KNOCKING AT OUR DOOR ON
SUNDAY NIGHT...AND WILL SEND A WEAK BACK DOOR COLD FRONT DOWN THE
LAKE. THE LEADING EDGE OF THIS SECONDARY SURGE OF COLD AIR WILL
TRIGGER A SIGNIFICANTLY COLDER STRETCH OF WEATHER TO KICK OFF THE
LAST FEW DAYS OF 2014. THERE MAY BE SOME WEAK LAKE EFFECT SNOW
SHOWERS GETTING INTO NE ILLINOIS...OTHERWISE INCREASING CLOUDS AND
COLDER. THEN AS THE TRULY ARCTIC AIR SPILLS IN MONDAY NIGHT...WE MAY
SEE SOME SNOW SHOWERS ALONG THE BAROCLINIC ZONE. MOISTURE IS NOT
IMPRESSIVE WITH THE FRONT...BUT THE COMBINED NE FLOW OFF THE LAKE
WITH MORE SIGNIFICANT INVERSION HEIGHTS AND MUCH COLDER AIR MAY
ALLOW FOR LAKE ENHANCEMENT AND SOME BETTER ACCUMULATION POTENTIAL.
THEN THE CHILL ENSUES FOR SEVERAL DAYS OF HIGHS ON EITHER SIDE OF 20
AND LOWS IN THE SINGLE DIGITS AND TEENS AS WE REMAIN IN NW FLOW. THE
UPSIDE...LIKELY SOME MORE SUN TO ENJOY TO END THE YEAR...AS ANY
SHORTWAVE ENERGY ROTATING THROUGH FROM THE CANADIAN VORTEX WILL
EITHER REMAIN NORTH OR GENERALLY BE WEAK AS THE ONE THAT COMES
THROUGH TUESDAY NIGHT. SOME MODIFICATION TO THE COLD AIR MASS
ARRIVES ON NEW YEARS DAY AND MORE SO FRIDAY AS WE RETURN TO
SOUTHERLY FLOW. AS THIS OCCURS...WILL HAVE TO WATCH IF LOW
PRESSURE THAT CLOSES OFF OVER CALIFORNIA EARLIER IN THE WEEK
PHASES WITH THE NORTHERN STREAM LOW OR REMAINS FARTHER SOUTH AS
THIS WILL HAVE IMPLICATIONS FOR ANY PRECIPITATION CHANCES TOWARD
WEEKS END.
KMD
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* WEST WINDS GUSTING UP TO 30 KT THROUGH THE AFTN.
* MVFR CIGS PERSISTING THROUGH THE EVENING.
JEE
//DISCUSSION...UPDATED 18Z...
THE COLD FRONT EXTENDS FROM PWK THROUGH FORD COUNTY IL AND IT WILL
CONTINUE EAST WITH 30KT GUSTS ALONG THE FRONT. SCATTERED LIGHT
SHOWERS ARE ALONG THE FRONT AND STILL NOT EXPECTING ANY
SIGNIFICANT IMPACT FROM THEM AS THEY QUICKLY SHIFT EAST OF THE
TERMINALS. IFR CIGS LIFT TO MVFR BEHIND THE FRONT AS WELL.
VFR CONDITIONS EXTEND FROM CENTRAL MN THROUGH NE AND EXPECTING
CIGS TO SCATTER OUT OVERNIGHT. HIGH PRESSURE SPREADS IN AND NW
WINDS DIMINISH TO LESS THAN 20 KT OVERNIGHT. VERY WEAK
WINDS...LESS THAN 5 KT...VARY FROM WEST OR SOUTHWEST OVER RFD
TOMORROW TO NORTHWEST TO NORTH OVER THE EASTERN TERMINALS.
JEE
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH CONFIDENCE IN CIG TRENDS...MEDIUM CONFIDENCE IN TIMING.
* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
JEE
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT...VFR.
MONDAY...CHANCE OF -SN OR FLURRIES...ESPECIALLY AT NIGHT. MVFR
CIGS LIKELY.
TUESDAY THROUGH FRIDAY...PREDOMINANTLY VFR.
IZZI
&&
.MARINE...
158 AM CST
LOW OVER EASTERN IOWA WILL QUICKLY DEEPEN THROUGH THIS EVENING
AS IT TRACKS NORTHEAST ACROSS NORTHERN LAKE MICHIGAN AND
EVENTUALLY OFF INTO QUEBEC. DUE TO THE BRIEF BUT RAPID DEEPENING
AND COLD AIR ADVECTION THIS AFTERNOON THERE COULD BE A VERY BRIEF
WINDOW OF GALES BEHIND THE FRONT FOR AN HOUR OR TWO OVER SOUTHERN
PORTIONS OF THE LAKE. DURATION LOOKS TO BE TOO SHORT FOR GALE
WARNING THOUGH SO NO HEADLINE PLANNED FOR OPEN WATERS. WINDS/WAVES
LOOK TO RAPIDLY SUBSIDE TONIGHT INTO MONDAY BEFORE AN ARCTIC FRONT
BEGINS WORKING SOUTH DOWN THE LAKE MONDAY NIGHT INTO TUESDAY.
TIGHT GRADIENT BEHIND THE FRONT ALONG WITH VERY COLD AIR AND
UNSTABLE CONDITIONS SHOULD ALLOW FOR STRONG NORTHERLIES TO
DEVELOP...POSSIBLY TO NEAR GALE FORCE BEHIND THE FRONT. THAT
SHOULD MARK THE START OF AN ACTIVE PERIOD ON THE LAKE WITH LOW
PRESSURE TRACKING ACROSS CANADA MIDWEEK DRAGGING A FRONT ACROSS
THE LAKE AND TIGHTENING THE PRESSURE GRADIENT AND PROBABLY LEADING
TO A PERIOD OF WESTERLY GALES WEDNESDAY/EARLY THURSDAY TIME FRAME.
IZZI
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 4 AM SUNDAY.
SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO GARY IN UNTIL 10 PM
SATURDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1038 AM CST Sat Dec 27 2014
.UPDATE...
ISSUED AT 1033 AM CST SAT DEC 27 2014
Weak cold front making its way through the state this morning and
has just passed over I-55 according to the depiction on radar and
the wind shift to more westerly in the obs. Cooler temps on the way
and a non-diurnal trend anticipated for locations behind the
front. Some minor precip along the boundary, but majority of radar
returns post-frontal not producing much in the way of measurable precip,
with the vast majority being drizzle. Only a few obs even picking
up on that. Not going to update the pops too much as the better
chances for rain remain in the southeast for the rest of the day.
Some small updates here and there, but nothing large scale. Will
reissue the zones only to refresh the morning wording closer to
noon.
&&
.SHORT TERM...(Today)
ISSUED AT 324 AM CST SAT DEC 27 2014
08z/2am surface analysis shows 1013mb low just north of KMLI, with
frontal boundary extending southwestward into Texas. Airmass ahead
of the front was initially quite dry as evidenced by the 00z KILX
upper air sounding: however, shallow low-level moisture has been on
the increase throughout the night. Surface dewpoints have reached
the middle 40s across central Illinois, while a plume of 50s
dewpoints is noted further upstream pushing into Arkansas. LAPS
soundings show this increasing moisture, with most local profiles
now saturated below 700mb. As low pressure tracks further
northeastward into Wisconsin, it will pull the cold front into the
area later this morning, then to the Indiana border by mid to late
afternoon. Continued moisture pooling along/ahead of the front
will result in increasingly deep moisture profiles, particularly
across the E/SE CWA this afternoon. HRRR suggests only scattered
light showers across much of the area this morning, then shows
more widespread precipitation developing along/east of I-57 this
afternoon. Think this solution makes sense as front gradually taps
into increasing amounts of Gulf moisture as it moves further east.
As a result, will carry chance PoPs across the western half of the
CWA throughout the day, with chance PoPs increasing to likely
across the E/SE this afternoon. With cold front passing through
the area, high temperatures will be achieved this morning,
followed by brisk westerly winds and falling temperatures later in
the day. Due to very mild current temps, have generally gone 2-4
degrees above MAV guidance numbers. End result will be highs in
the upper 40s and lower 50s, with temps dropping into the 30s
along/west of I-55 during the afternoon.
&&
.LONG TERM...(Tonight through Friday)
ISSUED AT 324 AM CST SAT DEC 27 2014
Cold front will slowly push eastward into the Ohio River Valley
tonight, with clouds and showers lingering across the E/SE through
at least the evening hours. NAM is fastest with the departure of
the precip, while GFS tends to keep it around through the entire
night. Based on slow forward movement of the front, have trended
toward the slower GFS. As a result, will maintain low chance PoPs
along/south of I-70 through the overnight hours. As temperatures
slowly fall into the lower to middle 30s across this area, any
lingering rain showers may mix with or change to light snow late.
Further northwest, skies will clear across the Illinois River
Valley, allowing lows to bottom out in the lower to middle 20s.
Sunshine and seasonably cool temps in the 30s will prevail Sunday
into Monday, before a surge of cold air arrives next week. Models
have been consistently showing strong 1050mb high building southward
out of western Canada into the central CONUS by Tuesday/Wednesday.
Weak synoptic lift along the leading edge of the cold air may be
enough to trigger a few flurries across the area Monday night, but
the main story will be the colder temps. High temps will remain in
the 20s Tuesday/Wednesday, while overnight lows dip into the single
digits and teens. After that, Canadian high pressure will gradually
slide east of the region, allowing a southern stream system to
approach by the end of the week. Model solutions vary with this
feature, so forecast confidence remains low at this point. ECMWF
aggressively brings precip northward into south-central Illinois as
early as Thursday night, while the GFS is about 12-18 hours
slower. Meanwhile, the GEM suggests the system may remain largely
southeast of the area across the Ohio River Valley. Given the
uncertainties, have opted to go with a dry forecast Thursday night,
and to slow precip onset on Friday. Have trimmed Friday PoPs to
just slight chance, with higher precip chances arriving Friday night
into Saturday. Think slower/colder is the way to go, especially
given the Canadian airmass that will initially be in place. End
result will be a chance of snow or a rain/snow mix mainly Friday
night into Saturday.
&&
.AVIATION...(For the 12Z TAFS through 12Z Sunday morning)
ISSUED AT 533 AM CST SAT DEC 27 2014
Widespread IFR conditions (mainly CIGS) can be expected across the
central Illinois terminals to start the 12Z TAF valid time. These
low CIGS are occurring in an unseasonably warm/moist airmass ahead
of an approaching cold front. CIGS should quickly rise to MVFR
with the passage of a cold front later this morning or early this
afternoon. The passage of this front will have winds swinging
around from the southwest to the west. Expect low clouds to
scatter out this evening as drier air filters into the region
behind the front. This drier air will also be accompanied by a
wind shift to the northwest.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HJS
SHORT TERM...Barnes
LONG TERM...Barnes
AVIATION...Bak
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
332 PM EST SAT DEC 27 2014
.UPDATE...
THE SYNOPSIS...NEAR TERM AND SHORT TERM SECTIONS HAVE BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 324 PM EST SAT DEC 27 2014
A COLD FRONT WILL MOVE EAST ACROSS OUR REGION TONIGHT. A DRY
SECONDARY ARCTIC COLD FRONT WILL MOVE SOUTHEAST ACROSS OUR REGION
AROUND TUESDAY. IN THE LONG TERM AN ARCTIC HIGH PRESSURE SYSTEM WILL
BRING DRY AND COLD WEATHER. HOWEVER MIXED PRECIPITATION IS POSSIBLE
AGAIN THIS FRIDAY THROUGH NEXT SATURDAY AS MODELS SHOW A LOW
PRESSURE SYSTEM MOVING INTO THE LOWER MISSISSIPPI VALLEY.
&&
.NEAR TERM /REST OF AFTERNOON THROUGH TONIGHT/...
ISSUED AT 324 PM EST SAT DEC 27 2014
TRENDS AMONG THE MODELS REMAIN VIRTUALLY THE SAME...WITH THE EURO
AND NAM BEING MUCH MORE PROGRESSIVE THAN THE GFS AND GEM. AS
USUAL...THE SREF AND HRRR TAKE A DECENT BLEND OF THE FASTER AND
SLOWER SOLUTIONS...SO LEANED HEAVILY TOWARD THIS GUIDANCE WHEN
CREATING THE POPS FOR TONIGHT. ALSO TRIED TO WORK IN WHAT IS
CURRENTLY ON THE RADAR SCOPE WITH ONE WAVE OF LIGHT RAIN MOVING IN
FROM THE SOUTH...WHICH WILL LATER THE EXIT THE FORECAST AREA BY
00Z. WHILE THE MAIN AREA OF PRECIPITATION IS BEGINNING TO APPROACH
THE CENTRAL INDIANA AREA FROM CENTRAL ILLINOIS. THIS AREA WILL
MAKE IT/S WAY THROUGH THE BULK OF CENTRAL INDIANA FROM 00Z TO 08Z.
WITH A FEW COUNTIES TO THE SOUTHEAST COUNTIES SEEING SOME
LINGERING POPS INTO EARLY SUNDAY MORNING.
ATTENTION THEN TURNS TO PRECIP TYPE AND TIMING...BOTH OF WHICH
WILL BE TRICKY. ALL OF THE PRECIP OVER CENTRAL INDIANA WILL BE IN
THE FORM OF RAIN THROUGH THIS EVENING. COLDER AIR WILL BEGIN
WORKING INTO THE NORTHWEST COUNTIES OF THE CWA ABOUT MIDNIGHT AND
PUSH TOWARD THE I-70 CORRIDOR BY 2-3 AM. BEST CHANCE IN TERMS OF
PRECIP TYPE ARE STILL A -RA/SN MIX...CANNOT RULE OUT ANY SLEET
MIXING IN AT TIMES HOWEVER NOT WIDESPREAD ENOUGH TO HAVE THE
CONFIDENCE TO INCLUDE IT IN FORECAST AT THIS TIME. THIS MIX WILL
WORK IT/S WAY TOWARD THE E/SE EARLY SUNDAY MORNING...WHILE PRECIP
BEHIND IT BEGINS TO WIND DOWN AND DRY OUT OVER MOST OF THE
FORECAST AREA BY 12Z SUNDAY MORNING. LOWS 31-36.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY/...
ISSUED AT 324 PM EST SAT DEC 27 2014
AS MENTIONED IN ABOVE DISCUSSION...THERE WILL LIKELY BE SOME REMNANT
MIXTURE OF -RA/SN FOR EARLY SUNDAY MORNING ACROSS SEVERAL OF THE
SOUTHEASTERN COUNTIES BEFORE THAT FRONT MOVES FARTHER FROM THE AREA
AND DRIER AND COLDER AIR FILTERS BACK INTO THE AREA. WILL CONTINUE
LOW CHANCE POPS THERE AT LEAST THROUGH 14-15Z SUNDAY MORNING.
DRY AND COOLER WEATHER WILL PERSIST ACROSS THE REGION FOR THE BETTER
HALF OF THE NEXT WEEK AS A LARGE AREA OF HIGH PRESSURE REMAINS IN
CONTROL OVER THE REGION. MODELS INDICATE HIGHS IN THE UPPER 30S
SUNDAY AND PERHAPS A DEGREE OR TWO WARMER MONDAY. LOWS WILL BE IN
THE MIDDLE TO UPPER 20S SUNDAY NIGHT AND LOWER OR MIDDLE 20S MONDAY
NIGHT AS A DRY SECONDARY COLD FRONT MOVES THROUGH.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
ISSUED AT 240 PM EST SAT DEC 27 2014
MAIN FOCUS FOR THE EXTENDED PERIOD WILL BE POPS AND PRECIPITATION
TYPE STARTING FRIDAY. PRIOR TO THAT...TEMPERATURES WILL BE THE
BIGGEST ISSUE AS STRONG COLD WESTERN CANADIAN HIGH PRESSURE WILL
SETTLE ACROSS THE OHIO VALLEY TO END THE OLD YEAR AND START THE NEW
ONE.
DETERMINISTIC MODELS ARE IN DECENT AGREEMENT THAT AN UPPER LOW WILL
BE OVER NORTHEASTERN ARIZONA DURING THE EVENING OF THE FIRST DAY OF
2015. HOWEVER...THE MODELS THEN DIVERGE RAPIDLY WITH THE MUCH
QUICKER 12Z GFS BRINGING A STRONGER SURFACE SYSTEM BUT WEAK UPPER
WAVE OVER THE OHIO VALLEY FRIDAY NIGHT. MEANWHILE...THE 12Z ECMWF
HAS EVEN A WEAKER BUT MUCH SLOWER WAVE LIFT NORTHEAST TO SOUTHERN
ILLINOIS BY NEXT SATURDAY EVENING. THE EURO ALSO HAS THE MAIN
SURFACE LOW WELL SOUTHWEST OF THE 12Z GFS POSITION SATURDAY EVENING.
THE ECMWF HAS THE SURFACE LOW OVER EASTERN KENTUCKY...WHILE THE GFS
HAS IT OVER SOUTHERN QUEBEC. DESPITE ALL THESE DIFFERENCES...BOTH
MODELS START THE QPF ON FRIDAY WITH THE HEAVIEST PRECIPITATION ALONG
THE OHIO RIVER. MEANWHILE...THE EURO WAS HOLDING MORE QPF AROUND ON
SUNDAY THAN THE GFS. SO...STILL EXPECT THE PRECIPITATION TO SPREAD
NORTHEAST ACROSS THE AREA ON FRIDAY. WITH CONFIDENCE IN TIMING
LOW...WILL ACCEPT THE REGIONAL BLEND THAT KEEPS DECENT POPS AROUND
NEXT SATURDAY AS HINTED AT BY THE EURO.
REGARDING PRECIPITATION TYPE...WILL NOT MAKE MANY CHANGES WITH THE
MODEL DIFFERENCES. CONFIDENCE NOT GOOD AS TO WHERE THE RAIN/SNOW
LINE WILL BE IN SPACE AND TIME. HOWEVER...NORTHEASTERN PARTS OF THE
FORECAST AREA WILL BE MORE LIKELY TO SEE FROZEN OR MIXED
PRECIPITATION THEN THE SOUTHWESTERN ONES ON FRIDAY BASED ON
THERMAL PROFILES FROM BUFKIT SOUNDINGS AS WELL AS PARTIAL
THICKNESSES. FRIDAY NIGHT AND SATURDAY...THE NORTHWESTERN COUNTIES
WOULD HAVE A HIGHER CHANCE OF MIXED OR FROZEN PRECIPITATION THAN THE
SOUTHEAST AS COLDER AIR MOVES IN FROM THE NORTHWEST IN THE WAKE OF
THE SURFACE SYSTEM. BUFKIT SOUNDINGS EVEN SUGGEST FREEZING RAIN OR
SLEET COULD POSSIBLY MIX IN AT TIMES FRIDAY NIGHT.
GENERALLY ACCEPTED THE REGIONAL BLEND TEMPERATURES. DO NOT FEEL
CONFIDENT ENOUGH TO MAKE CHANGES UNTIL THE MODELS HOPEFULLY COME
CLOSER TOGETHER IN SUBSEQUENT RUNS. AFTERNOON HIGHS IN THE 20S LOOK
GOOD ON NEW YEAR`S DAY WITH HIGHS MOSTLY IN THE 30S THEREAFTER.
MEANWHILE...NEW YEARS EVE NIGHT SHOULD BE THE COLDEST WITH OVERNIGHT
LOWS IN THE TEENS FOR THE FIRST SUNRISE OF THE YEAR. OVERNIGHT LOWS
WILL MOSTLY BE IN THE 20S AND 30S BY LATE WEEK.
&&
.AVIATION /DISCUSSION FOR THE 27/21Z TAF UPDATE/...
ISSUED AT 320 PM EST SAT DEC 27 2014
SOME ADJUSTMENT DOWNWARD TO CEILINGS AND VISIBILITIES REQUIRED TO
INITIAL PERIOD OF TAFS. PREVIOUS DISCUSSION FOLLOWS.
ISSUED AT 1200 PM EST SAT DEC 27 2014
DECENT CONFIDENCE THAT MVFR OR WORSE FLYING CONDITIONS ARE EXPECTED
TO BE OVER THE TERMINALS THE MAJORITY OF THIS AFTERNOON AND TONIGHT
BEFORE CONDITIONS IMPROVE TO VFR TOMORROW. MEANWHILE...RAIN WILL BE
INCREASING AT OR SHORTLY AFTER ISSUANCE TIME AND SHOULD END AFTER
04Z AT LAF...06Z AT IND AND HUF AND 08Z AT BMG.
A COLD FRONT SHOULD REACH LAF AND HUF AROUND 22Z AND IND AND BMG
AROUND 00Z. WINDS WILL SWITCH FROM SOUTHWEST TO WEST AND THEN
NORTHWEST AFTER THE FRONTAL PASSAGE. WIND SPEEDS WILL BE 9 TO 12
KNOTS THIS AFTERNOON AND EVENING AND LESS THAN 10 KNOTS TONIGHT.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...SMF
NEAR TERM...SMF
SHORT TERM...SMF
LONG TERM...MK
AVIATION...MK/NIELD
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AREA FORECAST DISCUSSION
NWS JACKSON KY
1257 PM EST SAT DEC 27 2014
.UPDATE...
ISSUED AT 1256 PM EST SAT DEC 27 2014
ALL OF THE SPRINKLES AND WEAK SHOWER ACTIVITY HAS DISSIPATED AND
UPSTREAM...WHICH IS DOWN TO THE WEST AND SOUTHWEST...MORE SHOWERS ARE
MOVING NORTHEAST INTO THE FORECAST AREA. HAVE UPDATED THE FORECAST TO
TAKE OUT MORNING MENTION OF SPRINKLES AND SHOWERS. THE BULK OF THE
ACTIVITY WILL MAKE IT INTO THE FAR WESTERN PORTIONS OF THE CWA
TOWARDS THE EVENING TIME FRAME. TEMPERATURES ARE ALSO A BIT WARMER
INTO THIS AFTERNOON THAN ANTICIPATED SO BUMPED UP THE TEMPS A DEGREE
OR TWO...ESPECIALLY IN THE SOUTHERN LOCATIONS. HAVE ISSUED A NEW ZFP
TO ADDRESS THIS UPDATE.
UPDATE ISSUED AT 1040 AM EST SAT DEC 27 2014
THE SPRINKLE AND SHOWER ACTIVITY IS BEGINNING TO WIND DOWN AS IT
SHIFTS TO THE NORTHEAST THROUGH THE AREA. IT SEEMS THAT THE CURRENT
FORECAST HAS THE PRECIP HANDLED FOR NOW. WILL HAVE TO ISSUE A NEW ZFP
WHEN THE PRECIP EXITS THE AREA AS THERE WILL BE MORNING WORDING THAT
NEEDS ADDRESSED ANYWAY. DESPITE THIS LIGHT ACTIVITY...THE MORNING
INTO THE NOON PERIOD LOOKS TO BE QUIET. TRENDS ARE STILL ON TRACK FOR
THE LARGE SWATH OF PRECIP TO ARRIVE THIS EVENING. FOR NOW...JUST SENT
OUT A NEW SET OF GRIDS WITH THE LATEST OBS AND WILL CONTINUE TO
ADDRESS THE LIGHT SPRINKLES WITH A GRAPHICAL NOW CAST.
UPDATE ISSUED AT 730 AM EST SAT DEC 27 2014
BAND OF RAIN SHOWERS HAS BEEN MOVING ACROSS THE COMMONWEALTH EARLY
THIS MORNING. HRRR HAS BEEN CONSISTENT WITH THE IDEA OF THIS BAND
WEAKENING AND DISSIPATING AS IT MOVES EASTWARD. HOWEVER...THE HRRR
HAS TRENDED SLOWER WITH THE OVERALL DISSIPATION WITH EACH NEW RUN.
MOST RECENT RUN INDICATES THAT SOME OF THE SHOWER ACTIVITY COULD
HOLD TOGETHER LONG ENOUGH TO PROVIDE US WITH SOME RAIN...MAINLY
ACROSS OUR BLUE GRASS COUNTIES. THIS TREND SEEMS TO BE SUPPORTED BY
THE FACT THAT THE BAND HAS BEEN FAIRLY PERSISTENT THUS FAR. THEREFORE
INTRODUCED POPS ACROSS OUR NORTH FOR THE EARLY AND MID MORNING TIME
FRAME WHILE MAINTAINING A GRADUAL WEAKENING TREND. ALSO INCLUDED A
SWATH OF SPRINKLES AHEAD OF THIS INITIAL BAND FOR SOME AREAS THAT
ARE NOT EXPECTED TO SEE ACTUAL SHOWERS. OTHERWISE FORECAST APPEARS ON
TRACK.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 337 AM EST SAT DEC 27 2014
MODELS ARE IN GOOD AGREEMENT THROUGH THE SHORT TERM...THOUGH THEY
WERE LATE IN PICKING UP ON POTENTIAL SHOWER ACTIVITY CURRENTLY MOVING
EAST OF OUR AREA. HRRR IS PICKING UP ON ADDITIONAL SHOWER ACTIVITY
FAR TO OUR WEST...OVER THE WESTERN END OF THE COMMONWEALTH AND DOES
BRING THAT EASTWARD TOWARDS OUR AREA. BUT ACTIVITY SUPPOSEDLY WEAKENS
AND DISSIPATES BY THE TIME IT REACHES OUR CWA AROUND MID MORNING.
OTHER OPERATIONAL MODELS TEND TO SUPPORT THIS SCENARIO THOUGH WILL
HAVE TO WATCH THIS CAREFULLY THROUGH THE MORNING IN CASE MODELS WIND
UP HANDLING THIS POORLY AS WELL AND POPS NEED TO BE RAMPED UP MORE
QUICKLY THROUGH THE DAY.
MID/UPPER LEVEL RIDGE...CENTERED OVER CUBA IS RETREATING EASTWARD
WITH APPROACH OF SHORT WAVE ENERGY AND TROUGH LIFTING OUT OF THE
WESTERN GREAT BASIN...SOUTHWEST CONUS. AT THE SFC...HIGH PRESSURE
CENTERED OVER THE CENTRAL ATLANTIC COASTAL REGION IS ALSO BEGINNING
TO RETREAT EASTWARD. CONTINUED MOVEMENT OF MID/UPPER LEVEL TROUGH
OUT OF THE WESTERN CONUS WILL INDUCE A SERIES OF SFC LOWS...THE FIRST
DEVELOPING OVER THE EASTERN PLAINS AND MOVING THROUGH THE GREAT
LAKES BY LATE TODAY. THIS FIRST LOW WILL DRAG A SFC COLD FRONTAL
BOUNDARY INTO THE OHIO VALLEY TONIGHT...REACHING OUR CWA BY SUNDAY
MORNING. A SECOND LOW WILL DEVELOP MUCH FURTHER SOUTH OVER THE
SOUTHERN MISSISSIPPI VALLEY REGION AND TRACK NORTHEAST ALONG THE
FRONT AS THE SFC BOUNDARY PUSHES ACROSS THE APPALACHIANS SUNDAY
MORNING. THIS WILL KEEP OUR WEATHER WET THROUGH TO THE END OF THE
SHORT TERM.
FOR SENSIBLE WEATHER...WEAK IMPULSE RESPONSIBLE FOR SPRINKLES AND
VERY ISOLATED SHOWER ACTIVITY OVER OUR AREA EARLY THIS MORNING IS
EXITING TO OUR EAST...WITH CORRESPONDING ACTIVITY EXITING AS WELL.
MID AND HIGH LEVEL CLOUDS WILL CONTINUE TO THICKEN AND LOWER WITH
TIME...THOUGH WE COULD SEE A FEW BREAKS AT TIMES THROUGH THE DAY.
COULD SEE SOME ADDITIONAL SPRINKLES ACROSS PORTIONS OF OUR AREA BY
MID MORNING TO NOON AS THE SECOND AREA OF ACTIVITY TO OUR FAR WEST
WEAKENS WHILE MOVING EASTWARD. OUR MAIN EVENT...RAIN ASSOCIATED WITH
THE APPROACHING COLD FRONTAL SYSTEM WILL BEGIN TO OVERSPREAD OUR AREA
FROM THE WEST LATE THIS AFTERNOON. RAIN WILL INCREASE THROUGH THE
OVERNIGHT AND LINGER THROUGH THE DAY SUNDAY AS THE AFOREMENTIONED
SECOND WAVE OF LOW PRESSURE RIDES UP INTO THE SOUTHERN APPALACHIANS.
INCREASED POPS FOR TONIGHT AND SUNDAY FOLLOWING THE LEAD OF GUIDANCE.
TEMPERATURES CONTINUE TO MODERATE WITH A RELATIVELY LIMITED DIURNAL
RANGE OVER THE NEXT 18 TO 24 HOURS DUE TO INCREASED CLOUD COVER. ALSO
PREFERRED TO GO WITH A NON DIURNAL TEMP TREND THROUGH THE DAY SUNDAY
AS COLDER AIR FILTERS IN BEHIND THE SFC COLD FRONT.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 337 AM EST SAT DEC 27 2014
FRONTAL BOUNDARY AND WAVES OF LOW PRESSURE WILL SLOWLY PUSH EAST OF
THE CWA MOVING INTO THE LONG TERM PERIOD. SLOWLY LESSEN POPS
OVERNIGHT SUNDAY INTO MONDAY AS BETTER LIFT MOVES EAST OF THE REGION.
AFTER THIS THERE IS A UPPER LEVEL DISTURBANCE THAT MOVES ACROSS THE
REGION GOING INTO TUESDAY THIS WILL BRING SOME CLOUD COVER TO THE
REGION. OTHER THAN THAT NOT EXPECTING MUCH IN THE WAY OF PRECIP AS
HIGH PRESSURE CONTINUES BUILDS EAST WEDNESDAY WITH SKIES CLEARING OUT
THROUGH THE DAY. COOLER AIR WILL FILTER INTO THE REGION GIVING WAY TO
HIGHS IN THE LOW TO MID 30S FOR HIGHS ON WEDNESDAY. CONTINUED
CLEARING SKIES AND BUILDING HIGH PRESSURE WILL GIVE WAY TO GOOD
RADIATIONAL COOLING WEDNESDAY NIGHT WITH LOWS IN THE UPPER TEENS TO
LOWER 20S ACROSS THE REGION. MORE UNCERTAINTY IN THE MODELS EXIST AS
WE MOVE INTO THE LONGER RANGE PORTION OF THE LONG TERM. HIGH PRESSURE
IS EXPECTED TO SLOWLY MOVE EAST AS WE MOVE INTO THURSDAY. RIGHT NOW
THURSDAY LOOKS DRY...HOWEVER A LOW PRESSURE SYSTEM IS EXPECT TO
DEVELOP ACROSS THE SOUTHERN PLAINS THURSDAY/FRIDAY AS UPPER LEVEL LOW
EJECTS OUT OF THE FOUR CORNERS REGION. MOISTURE WILL SLOWLY SPREAD
NORTH AND EAST TOWARD THE OHIO VALLEY AS WE MOVE INTO FRIDAY. TIMING
ON THE PRECIP DIFFER AT THIS POINT WITH ECMWF MOST PROGRESSIVE. GIVEN
THE UNCERTAINTY DID STICK REASONABLY CLOSE TO THE MODEL BLEND AND
TRYING TO KEEP SOME CONSISTENCY/COLLABORATION. THIS DOES GIVE WAY TO
SLIGHT POPS THURSDAY NIGHT AND CHANCE POPS FRIDAY. GIVEN COOLER TEMPS
ONSET OF POPS WOULD BE A SNOW OR RAIN/SNOW MIX THURSDAY NIGHT INTO
EARLY FRIDAY. HOWEVER RIGHT NOW CONFIDENCE REMAINS LOW GIVEN MODEL
DIVERGENCE DURING THIS PERIOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1256 PM EST SAT DEC 27 2014
VFR CONDITIONS OVER THE AREA WILL BEGIN TO DEGRADE THROUGH THE
EVENING TO MVFR AND IFR CONDITIONS OVER NIGHT AS A MOISTURE LADEN
SYSTEM DEVELOPS AND MOVES NORTHEAST OUT OF THE LOWER MS RIVER VALLEY.
EXPECT RAIN TO DEVELOP INTO THE AREA AFTER 00Z WITH CEILINGS DROPPING
TO AIRFIELD MINIMUMS BY 12Z OVER MUCH OF THE AREA AND CONTINUING
THROUGH THE END OF THE TAF PERIOD. RAIN IS EXPECTED TO BE WIDESPREAD
THROUGH THE REST OF THE TAF PERIOD WITH LIGHT WINDS EXPECTED.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...SHALLENBERGER
SHORT TERM...RAY
LONG TERM...DJ
AVIATION...SHALLENBERGER
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1252 PM EST SAT DEC 27 2014
.UPDATE...
ISSUED AT 939 AM EST SAT DEC 27 2014
DIFFICULT HEADLINE DECISION THIS MORNING AS THERE WILL LIKELY BE A
SWATH OF SNOWFALL AMOUNTS RIGHT AROUND OUR 6IN/12HR CRITERIA OVER
CENTRAL UPPER MICHIGAN. BELIEVE THE SNOWFALL AMOUNTS THAT WE HAVE
IN THE FORECAST ARE IN LINE FOR WHAT IS EXPECTED WITH THIS LAST
AREA OF SNOW THAT WILL MOVE THROUGH THIS MORNING. THAT AREA WITH
THE FORECASTED HIGHEST AMOUNTS IS IN LINE WITH THE AREA OF RAPIDLY
COOLING CLOUD TOPS OVER CENTRAL UPPER MICHIGAN AND NORTHEAST
WISCONSIN AND MATCHES THE LATEST QPF AMOUNTS FROM THE RAP/HRRR. ON
THE WESTERN EDGE OF THIS SWATH (IRON/DICKINSON COUNTIES)...THEY HAVE
RECEIVED 2.5-3.5 INCHES OF SNOW THUS FAR OVER 9-10 HOURS AND WILL
RECEIVE ANOTHER 2-3 INCHES OVER THE NEXT 3-4HRS WHICH PUTS THEM ON
THE EDGE OF THE CRITERIA. FARTHER EAST...AMOUNTS HAVE BEEN LOWER AND
IN THE 1-2.5 INCH RANGE...BUT THEY WILL LIKELY SEE THE GREATEST
AMOUNTS OF 3.5-5 INCHES. THIS ALSO PUTS THOSE AREAS RIGHT AROUND THE
6 INCH CRITERIA. FEEL THE MOST CONFIDENT ON AMOUNTS JUST OVER
WARNING CRITERIA FROM NORTHERN DICKINSON THROUGH THE SOUTHEAST HALF
OF MARQUETTE AND WESTERN ALGER COUNTY...BUT NOT SURE IF THE UPGRADE
WITH ANOTHER 3-4HRS OF SNOW LEFT IS WORTH THE HEADLINE CHANGE. IN
ADDITION...THE OVERALL WORDING WILL STAY THE SAME. THUS...WILL
UPDATE THE WSW TO HIGHLIGHT THE HEAVIER SNOW OVER THE NEXT FEW HOURS
AND KEEP THE ADVISORIES AS IS...ESPECIALLY SINCE WEBCAMS SHOW MANY
LOCATIONS EAST OF A MARQUETTE TO IRON MOUNTAIN LINE STILL HAVING
MAINLY WET ROADS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 535 AM EST SAT DEC 27 2014
LATEST WATER VAPOR LOOP AND RUC ANALYSIS SHOWS A VIGOROUS AND
WELL-DEFINED SHORTWAVE LIFTING NE INTO SRN MN AND NW WI WITH
DEVELOPING BAROCLINIC LEAF STRUCTURE/DEFORMATION ZONE. MID-LVL FGEN
ASSOC WITH SHORTWAVE STRETCHING FROM SRN MN AND NW WI INTO THE UPPER
MI HELPING SUPPORT LIGHT TO MODERATE SNOW.
TODAY...MID-LVL FGEN STRETCHING ACROSS THE UPPER MIDWEST TO THE
UPPER GREAT LAKES WILL CONTINUE TO SUPPORT MODERATE SNOW INTO EARLY
AFTERNOON. BROAD SCALE SYNOPTIC ASCENT WILL BE AIDED BY UPPER
DIVERGENCE IN THE LEFT EXIT REGION OF THE 300 MB JET. NEGATIVE EPV
NOTED ON CROSS-SECTIONS WITHIN A REGION OF MID-LVL FRONTOGENESIS
COULD LEAD TO SOME LOCALLY HEAVIER SNOW BANDS AS SFC LOW TRACKS JUST
SE OF AREA THIS MORNING AND THEN ACROSS THE STRAITS EARLY THIS AFTERNOON.
MODEL CONSENSUS QPF ARGUES FOR AREA OF HEAVIER SNOW JUST NW OF LOW
TRACK ALONG AND EAST OF A LINE FROM IRON RIVER THROUGH ISHPEMING
WHERE MODELS SHOW STRONG 285-290K ISENTROPIC ASCENT OVER A SIX-HR
PERIOD WITH 4 G/KG MIXR ADVECTING ACROSS AREA. THIS SWATH OF HEAVIER
SNOW WILL TAPER OFF BY MID AFTERNOON AS MID-LVL FGEN WEAKENS AND
BEGINS TO MOVE NE WITH DEPARTING SFC LOW. MODEL AVG QPF FM .25 INCH
WEST TO NEAR .5 INCH OVER PORTIONS OF THE CENTRAL CWA WITH EXPECTED
SNOW/WATER RATIOS FM 15/1 WEST TO NEAR 12/1 EAST HALF SHOULD YIELD
TOTAL SNOW ACCUMULATION FM 2-5 INCHES WEST TO 3-6 INCHES CENTRAL.
SINCE 6 INCH AMOUNTS SHOULD BE FAIRLY LOCALIZED WILL CONTINUE WITH
WINTER WX ADVISORY HEADLINES AT THIS POINT AND NOT UPGRADE TO
WARNINGS...BUT SITUATION WILL DEFINITELY WARRANT MONITORING THIS
MORNING. ALSO HAVE DECIDED TO INCLUDE ONTONAGON AND SRN HOUGHTON IN
ADVISORIES AS THEY SHOULD BE ON WRN EDGE OF HEAVIER QPF THIS MORNING.
TONIGHT...WITH SYSTEM SNOW OVER BY LATE AFTERNOON FOR EAST...EXPECT
TRANSITION TO PURE LAKE EFFECT SNOW TONIGHT AS 850MB TEMPS FALL FROM
-10 TO -12C IN THE EVENING TO -12 TO -16C BY 12Z SUN UNDER LOW-LEVEL
W TO WNW FLOW. LARGE SCALE DEEP LAYER Q-VECTOR DIVERGENCE WILL
DOMINATE THIS EVENING AND NAM/GFS FCST SOUNDINGS SHOWING INVERSIONS
BASED NEAR 4KFT...ANY DEVELOPING LES WILL BE ON THE LIGHT SIDE OVER
THE KEWEENAW. HOWEVER...LATER TONIGHT THERE IS A POTENTIAL FOR SOME
WEAK ENHANCEMENT AS A SHORTWAVE PASSES ACROSS NRN ONTARIO AND SENDS
A SFC TROF S ACROSS THE UPPER LAKES. GFS/NAM FCST SOUNDINGS SHOW AN
INCREASE IN MOISTURE DEPTH AND LIFTING OF THE INVERSION. THIS
ENHANCEMENT COMBINED WITH FAVORABLE PLACEMENT OF DGZ WITHIN
CONVECTIVE BOUNDARY LAYER AND SHARPENING OF THE WIND
SHIFT/CONVERGENCE AS TROF MOVES THROUGH AREA COULD YIELD MODERATE
SNOW LATE TONIGHT WITH A QUICK 1 TO LOCALLY 3 INCHES OF SNOW IN NRN
ONTONAGON/HOUGHTON COUNTIES WHERE SHARPEST CONVERGENCE IS INDICATED
AND WHERE UPSLOPING WILL FURTHER AID SNOW ACCUMULATIONS.
WENT ON COLDER SIDE OF GUIDANCE FOR MIN TEMPS ESPECIALLY OVER THE
WRN INTERIOR AS PCPN WATER FALL TO LESS THAN .25 INCH UNDER LIGHT
WINDS...A PERIOD OF CLEARING SKIES AND FRESH SNOW COVER. COULD SEE
THE TYPICAL COLD SPOTS NEAR THE WI BORDER FALL NEAR ZERO.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 458 AM EST SAT DEC 27 2014
WILL START OUT 12Z SUNDAY WITH A COLD FRONT DRAPED ACROSS THE FAR W
CWA. THIS WILL BE THE FOCUS FOR LIGHT TO POTENTIALLY MODERATE SNOW
SHOWERS FROM AROUND ONTONAGON UP THROUGH THE KEWEENAW PENINSULA. AS
NOTED IN THE PREVIOUS DISCUSSION...A LES ADVISORY BY BE NEEDED FOR
ONTONAGON AND HOUGHTON COUNTIES. CURRENTLY FORECASTING 3-5IN OF NEW
SNOW IN THIS AREA OVERNIGHT THROUGH SUNDAY EVENING. WILL HOLD OFF ON
ISSUING ANYTHING AS ONTONAGON AND S HOUGHTON HAVE BEEN INCLUDED IN
THE INITIAL WINTER WX ADVISORY FOR TODAY.
WITH COOLER AIR SLIDING IN...LOOK FOR SNOW RATIOS TO BE ON THE
INCREASE...RANGING FROM AROUND 20-23:1 THROUGH MUCH OF THIS PERIOD.
THE SFC TROUGH WILL SLOWLY EXIT AS STRONG AND COLD HIGH PRESSURE
PUSHES FROM FAR NW CANADA SUNDAY TO BRITISH COLUMBIA/ALBERTA ON
MONDAY...WITH A SIZABLE RIDGE EXTENDING INTO THE UPPER GREAT LAKES.
THE LOWERING INVERSION HEIGHTS /AROUND 850MB AT IWD/ WILL START TO
BECOME A CONCERN FOR MODERATE/HEAVY SNOWFALL DEVELOPMENT FROM 00Z
MONDAY ON ACROSS THE CWA. STILL EXPECTING 12HR SNOW TOTALS OF 1-3IN
WHERE THE BEST CONVERGENCE DEVELOPS WITH PLENTY OF MOISTURE STILL
STUCK IN OUR STEADY NW FLOW INTO TUESDAY.
THE COLDEST AIR LOOKS TO SWING IN TUESDAY NIGHT...ON THE ORDER OF
-21 TO -24C. IF WINDS BECOME MORE WESTERLY AND THE INTERIOR W HALF
CLEARS OUT...THIS COULD BE A VERY CHILLY NIGHT. CURRENTLY CALLING
FOR -5 TO -10F LOWS BY DAYBREAK WEDNESDAY UNDER A PARTLY CLOUDY SKY.
THERE MAY BE A BRIEF REPRISE FROM THE STEADY NW TO WNW WINDS
WEDNESDAY INTO WEDNESDAY NIGHT. POPS/WX MAY NEED TO BE DIMINISHED
FROM THE CURRENT FCST FOR WEDNESDAY NIGHT IF THIS TREND HOLDS UP.
THERE IS PLENTY OF DISCREPANCIES BETWEEN THE AVAILABLE GUIDANCE AT
THIS POINT...VARYING FROM -20C 850MB AIR OVERHEAD ON GUSTY NW WINDS
/UP TO 40KTS AT 850MB/ FROM THE 27/00Z GFS...AND MORE W-WSW WINDS
WITH -12C 850MB TEMPERATURES OFF THE 26/12Z ECMWF. WILL KEEP GOING
WITH A GENERAL BLEND BETWEEN THE CONSENSUS AND OUR PREVIOUS FORECAST
BEYOND THIS POINT GIVEN THE MODERATE TO LOWER CONFIDENCE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1250 PM EST SAT DEC 27 2014
THE SYSTEM LEADING TO THE MODERATE SNOW ACROSS MUCH OF UPPER
MICHIGAN WILL BE QUICKLY LIFTING NORTHEAST AND OUT OF THE AREA OVER
THE NEXT COUPLE OF HOURS. HAVE ALREADY SEEN VISIBILITIES COMING UP
AT KIWD AS THE BACK EDGE OF THE SNOW IS DEPARTING. THAT WEST TO
EAST DIMINISHING TREND WILL CONTINUE AT ALL THREE SITES AND EXPECT
WINDS TO BACK TO THE WEST-NORTHWEST INTO THE EVENING. THIS SHOULD
LEAD TO A TREND TOWARDS VFR AT KIWD/KSAW...BUT KCMX MAY TRY TO HOLD
ONTO HIGH END MVFR THIS EVENING WITH SOME LAKE ENHANCED CLOUDS.
FOCUS THEN TURNS TO A SECOND TROUGH THAT WILL DROP ACROSS WESTERN
LAKE SUPERIOR LATE TONIGHT AND UPPER MICHIGAN ON SUNDAY. JUST AHEAD
OF THIS TROUGH...EXPECT LAKE EFFECT SNOW TO DEVELOP IN THE WESTERLY
WINDS AND AFFECT KCMX SHORTLY AFTER MIDNIGHT. THIS WILL LEAD TO A
PERIOD OF MODERATE SNOWFALL AND HAVE BROUGHT VSBYS BELOW ALTERNATE
LANDING MINS. ONCE THE TROUGH MOVES THROUGH...CONDITIONS WILL
BECOME LESS FAVORABLE AT KCMX AS WINDS TURN TO THE NORTHWEST BUT
BRING A BETTER OPPORTUNITY FOR SNOW AT KIWD. AT KSAW...EXPECT THE
VFR CONDITIONS TO REMAIN THROUGH MUCH OF THE MORNING...BUT BLOWOFF
FROM THE UPSTREAM LAKE EFFECT WILL LIKELY BRING SOME LIGHT SNOW
SHOWERS AND BORDERLINE MVFR/VFR CEILINGS AROUND NOON ON SUNDAY.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 535 AM EST SAT DEC 27 2014
EXPECT GENERALLY LIGHT WINDS INTO THIS MORNING AS A WEAK PRESSURE
GRADIENT IS IN PLACE DUE TO A SURFACE TROUGH STALLED OVER THE
MACKINAC STRAITS. BUT AS A LOW LIFTS NORTHEAST OF THE STRAITS THIS
AFTERNOON INTO QUEBEC TONIGHT...NORTHWEST WINDS WILL BE ON THE
INCREASE THIS AFTERNOON AND EVENING WITH GUSTS UP TO 30KTS OVER EAST
HALF. BEHIND THE LOW...A WEAK SURFACE TROUGH WILL REMAIN IN PLACE ON
SUNDAY AND KEEP WEST-NORTHWEST WINDS UP TO 25KTS IN PLACE. A HIGH
PRESSURE RIDGE BUILDING INTO THE AREA ON MONDAY FROM A STRONG HIGH
IN THE NORTHERN/CENTRAL PLAINS WILL LEAD TO NORTHWEST TO NORTHERLY
WINDS UP TO 25-30KTS THROUGH TUESDAY. AN APPROACHING TROUGH FROM A
LOW OVER HUDSON BAY ON TUESDAY NIGHT WILL LEAD TO A TIGHTER PRESSURE
GRADIENT AND WESTERLY GALES TO 35-40KTS LATE TUESDAY NIGHT INTO
WEDNESDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ006-
007-014-085.
WINTER WEATHER ADVISORY UNTIL 4 PM EST /3 PM CST/ THIS AFTERNOON
FOR MIZ004-005-010>013.
WINTER WEATHER ADVISORY UNTIL 1 PM EST /NOON CST/ THIS AFTERNOON
FOR MIZ002-009-084.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...SRF
SHORT TERM...VOSS
LONG TERM...KF
AVIATION...SRF
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1230 PM EST SAT DEC 27 2014
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 328 AM EST SAT DEC 27 2014
WE WILL SEE THE LAST OF THE MILD WEATHER TODAY WITH INTERMITTENT
LIGHT RAIN AND DRIZZLE. COLDER AIR MOVES IN TONIGHT WITH A SECOND
WAVE OF ARCTIC AIR MONDAY NIGHT THROUGH WEDNESDAY. HIGHS ONLY IN THE 20S
ARE EXPECTED DURING THE MIDDLE PORTION OF THE WEEK AND MAY
STRUGGLE TO REACH 20 DEGREES ON WEDNESDAY...ESPECIALLY NORTH OF GRAND
RAPIDS. SNOW ACCUMULATIONS ALSO APPEAR POSSIBLE MONDAY NIGHT INTO
WEDNESDAY. TEMPERATURES WILL MODERATE SLIGHTLY TOWARD THE END OF
THE WORK WEEK BEFORE ANOTHER SURGE OF ARCTIC AIR NEXT WEEKEND.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 328 AM EST SAT DEC 27 2014
TEMPERATURES HAD RISEN INTO THE MID 40S MAINLY ALONG AND SOUTH OF
I-96 AS OF THIS WRITING. TEMPS AND DEWPOINTS WILL CONTINUE TO
CREEP UP THIS MORNING. 06Z HRRR CONTINUES TO INDICATE PERIODS OF
LIGHT RAIN AND DRIZZLE TODAY...THE FIRST AFTER 10Z OR SO.
THE WEAK SURFACE LOW IS FORECAST TO DEEPEN TO AROUND 1008 MB OVER
NORTHERN LOWER MI BY 18Z. THE COLD FRONT THEN MOVES THROUGH
FOLLOWED BY A VEERING OF THE WINDS DURING THE AFTERNOON. SURFACE
TEMPS ARE EXPECTED TO REMAIN ABOVE FREEZING AT 00Z THIS
EVENING...AND MOISTURE QUICKLY BAILS AFTER 00Z. THE ONSHORE FLOW
IS ALSO SLIGHTLY DIVERGENT. FORECAST THINKING HAS NOT
CHANGED...LITTLE IF ANY SNOW TONIGHT.
QUIET WEATHER EXPECTED ON SUNDAY. A VERY STRONG 1057 MB HIGH
DEVELOPS OVER WESTERN CANADA AND AN EXTENSION OF THIS HIGH
PRESSURE SYSTEM TURNS LOW LEVEL FLOW NORTHEASTERLY BY MONDAY.
THINKING PARTLY SUNNY FOR NOW WITH HIGHS IN THE LOW TO MID 30S.
.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 328 AM EST SAT DEC 27 2014
MODELS ARE IN DECENT AGREEMENT IN SHOWING A DEEPENING UPPER LOW OVER
HUDSON BAY AS WE HEAD THROUGH THE EXTENDED PERIOD. THIS WILL RESULT
IN A COLDER THAN NORMAL PERIOD THROUGH THE LONG TERM PERIOD.
THE ARCTIC AIR WILL ARRIVE IN WAVES. MONDAY NIGHT THROUGH WEDNESDAY
WILL FEATURE COLD AIR ADVECTION. THE LOW LEVEL THERMAL TROUGH
PUSHES THROUGH ON WEDNESDAY. HIGHS ON WEDNESDAY MAY STRUGGLE TO
REACH 20 DEGREES...ESPECIALLY NORTH OF GRAND RAPIDS. WIND WILL
ACCOMPANY THIS ARCTIC AIRMASS AND SUB ZERO WIND CHILLS WILL OCCUR AT
TIMES. ALSO MODELS HAVE BEEN TRENDING TOWARD MORE MOISTURE IN THE
DGZ MON NIGHT INTO WED. THUS WE MAY END UP WITH SOME
ACCUMULATIONS. I DID TREND POPS UPWARD BASED ON THE TRENDS.
TEMPERATURES ARE LIKELY TO MODERATE SLIGHTLY THURSDAY INTO FRIDAY AS
WARM AIR ADVECTION DEVELOPS ON THE BACKSIDE OF THE DEPARTING
HIGH. THEY ARE EXPECTED TO STILL AVERAGE OUT BELOW NORMAL.
ANOTHER SURGE OF ARCTIC AIR WILL LIKELY PUSH IN OVER NEXT WEEKEND.
THIS IS WHEN THE SOUTHERN ROCKIES LOW KICKS OUT INTO THE PLAINS AND
TRACKS TO THE CENTRAL APPALACHIANS. AS THIS WAVE TRACKS EAST...AN
IMPRESSIVE SURGE OF ARCTIC AIR SINKS SOUTH THROUGH THE GREAT LAKES
REGION. THERE IS A RISK FOR SNOW ASSOCIATED WITH THE ARRIVAL OF
THIS NEXT REINFORCING SHOT OF ARCTIC AIR. OVERALL MODELS HAVE COME
INTO BETTER AGREEMENT OF THE TIMING AND DURATION OF THIS NEXT ARCTIC
AIRMASS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1230 PM EST SAT DEC 27 2014
IFR AND LOWER CONDITIONS ARE CURRENTLY IN PLACE AT ALL OF THE
TERMINALS ACROSS SW LOWER MICHIGAN EARLY AFTERNOON. THIS IS MAINLY
DUE TO LOW CLOUDS IN PLACE AND DUE TO DRIZZLE/FOG WITH A FEW
SHOWERS AROUND. WE EXPECT THE LOW CONDITIONS TO HOLD ON FOR A FEW
HOURS BEFORE CIGS LIFT AND VSBYS IMPROVE TO MVFR FROM WEST TO EAST LIKE
WHAT IS CURRENTLY HAPPENING UPSTREAM ACROSS WI AND IL. THE BETTER
CONDITIONS APPEAR TO BE OCCURRING AFTER THE PASSAGE OF THE COLD FRONT.
THE AREA WILL REMAIN UNDER MVFR CONDITIONS FOR MOST OF THE NIGHT
WITH CIGS OF AROUND 1500 FT EXPECTED. THESE CLOUDS SHOULD TEND TO
BREAK UP BY MID-LATE SUN MORNING AS HIGH PRESSURE BUILDS IN ACROSS
THE AREA.
&&
.MARINE...
ISSUED AT 328 AM EST SAT DEC 27 2014
A SMALL CRAFT ADVISORY HAS BEEN ISSUED FOR 11 AM TODAY THROUGH 11
AM SUNDAY. AS THE SURFACE LOW APPROACHES...SOUTHERLY WINDS WILL
INCREASE TO 15 TO 25 KNOTS TODAY. WINDS WILL VEER WEST TO 30 KNOTS
LATE THIS AFTERNOON AND EVENING. WAVES WILL BUILD TO 4 TO 8 FEET
NORTH OF HOLLAND AND 3 TO 5 FEET SOUTH OF HOLLAND. WEST WINDS WILL
VEER NORTHWESTERLY TONIGHT.
&&
.HYDROLOGY...
ISSUED AT 328 AM EST SAT DEC 27 2014
AROUND A TENTH OF AN INCH OR LESS OF RAINFALL IS EXPECTED
TODAY...WITH SLIGHTLY HIGHER AMOUNTS POSSIBLE TOWARD LUDINGTON.
THIS LIGHT RAINFALL IS NOT EXPECTED TO HAVE A SIGNIFICANT IMPACT
ON RIVERS. ALL RIVER FLOOD ADVISORIES HAVE BEEN CANCELED.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 11 AM EST SUNDAY FOR LMZ844>849.
&&
$$
SYNOPSIS...EBW
SHORT TERM...EBW
LONG TERM...MJS
AVIATION...NJJ
HYDROLOGY...EBW
MARINE...EBW
AREA FORECAST DISCUSSION...UPDATED
NWS TWIN CITIES/CHANHASSEN MN
1210 PM CST SAT DEC 27 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 329 AM CST SAT DEC 27 2014
AFTER TAKING MOST OF DECEMBER OFF...THE SHORT TERM PERIOD MARKS THE
BEGINNING OF THE RETURN OF WEATHER THAT IS MORE TYPICAL OF WHAT WE
WOULD EXPECT IN THE HEART OF WINTER...AT LEAST FOR TEMPERATURES.
FEATURE DRIVING SNOW ACROSS THE AREA THIS MORNING SHOWS UP WELL ON
SATELLITE WITH A NICE SWIRL MOVING INTO THE SIOUX FALLS AREA...WITH
A NICE DRY SLOT NOSING INTO SE MN. THIS DRY SLOT IS ASSOCIATED WITH
A TROWAL...WHICH HAS HELPED FORCE A NICE DEFORMATION BAND OF PRECIP
TO THE NW OF IT. MODELS GOING BACK TO THE 00Z RUNS LAST NIGHT HAVE
ACTUALLY DONE A GOOD JOB HANDLING THIS SNOW AND PRETTY MUCH FOLLOWED
THE HOPWRF AND HRRR FOR ENDING SNOW ACROSS THE AREA THIS MORNING.
EVERYTHING APPEARS ON TRACK FOR A HEALTHY SWATH OF 3 TO 5 INCHES.
BACK TO THE WEST OF THIS LOW...THERE IS A RIDGE AXIS EXTENDING FROM
ERN COLORADO UP INTO THE ERN DAKOTAS. TEMPS AND DEWPS FALL OFF TO
WITHIN 10 DEGS OF EITHER SIDE OF ZERO WITHIN THE RIDGE AXIS...THOUGH
THIS RIDGE AXIS ALSO HAS WHAT HAS BEEN A RARITY THIS MONTH...MOSTLY
CLEAR SKIES. ITS LOOKING LIKE GOOD BET FOR SEEING SOME SUN TODAY
WEST OF I-35. EAST OF I-35...THE CLEARING WILL BE RACING
SUNSET...THOUGH BY THE TIME YOU GET TO EAU CLAIRE...IT`S A PRETTY
GOOD BET THAT SKIES WILL REMAIN OVERCAST THROUGH THE DURATION OF
DAYLIGHT HOURS. THESE MAINLY CLEAR SKIES MAY CAUSE TEMPERATURES TO
BE A BIT COOLER THAN WHAT IS CURRENTLY FORECAST TONIGHT...ESPECIALLY
WHERE WE ARE SEEING SNOW RIGHT NOW FROM SOUTHERN MN INTO WRN WI. OF
COURSE OUR TIME WITH CLEARISH SKIES WILL BE SHORT LIVED...AS BY 12Z
SUNDAY...THE ARCTIC BOUNDARY WILL BE SLIPPING INTO CENTRAL MN...WITH
CLOUD COVER INCREASING AHEAD OF THE FRONT AS IT DROPS SOUTH ACROSS
NRN MN THROUGH THE NIGHT.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 329 AM CST SAT DEC 27 2014
THE MAIN HIGHLIGHT OF THE LONG TERM FORECAST PERIOD WILL BE THE
RETURN TO BELOW NORMAL TEMPERATURES BEFORE WE RING IN THE NEW
YEAR. OTHER THAN A SLIM CHANCE FOR SNOWFALL ON SUNDAY NIGHT INTO
MONDAY AS THE ARCTIC BOUNDARY RESPONSIBLE FOR THE AFOREMENTIONED
COOL DOWN IN TEMPERATURES MOVES THROUGH...DRY WEATHER IS EXPECTED
UNTIL POSSIBLY NEXT FRIDAY.
SUNDAY WILL LIKELY BE THE ONE AND ONLY MILD DAY THROUGH MOST OF
THE UPCOMING WEEK IN ADVANCE OF THE COLD FRONT. MODEL AGREEMENT WITH
THIS FEATURE HAS NOT REALLY SHOWN MUCH IMPROVEMENT OVER THE LAST
24 HOURS. THE ECMWF HAS BEEN FAIRLY INSISTENT THAT THE FORECAST
AREA WILL MISS OUT ON SNOWFALL WITH THIS FEATURE...WHILE THE
SREF...NAM...AND NOW 27.00 GFS THINK SOUTHERN MN WILL SEE A 1-3
INCH SNOWFALL ON SUNDAY NIGHT AND MONDAY MORNING. SINCE THE ECMWF
IS A BIT OF AN OUTLIER FROM THE OVERALL MODEL CONSENSUS SOLUTION...WHICH
HAS SHOWN UP FOR MULTIPLE RUNS...HAVE INCLUDED 30 POPS FOR 00Z-18Z
MONDAY GENERALLY SOUTH OF INTERSTATE 94. HAVE HOWEVER KEPT SNOWFALL
ACCUMULATIONS AROUND ONE INCH OR LESS WITH THE THOUGHT THE
FORCING/MOISTURE MIGHT BE WEAKER/LOWER THAN PROGGED BY THE
CONSENSUS.
WHILE CONFIDENCE IS RATHER LOW WITH RESPECT TO SNOWFALL CHANCES AS
THIS BOUNDARY SURGES ACROSS THE AREA...WHAT IS MORE CERTAIN IS
THAT A BLAST OF COLDER AIR WILL FOLLOW IN ITS WAKE. THERE IS STILL
FINE AGREEMENT THAT H85 TEMPERATURES WILL REDUCE TO -18C TO -20C
BY TUESDAY. SUB-ZERO LOWS FOR TUESDAY AND WEDNESDAY MORNINGS ARE
FAIRLY CERTAIN...ALONG WITH HIGHS IN THE SINGLE DIGITS TO LOW
TEENS. WIND CHILLS WILL SNEAK TO AROUND -20F TO -30F ON MONDAY
NIGHT AND TUESDAY NIGHT...BUT MODERATE A TAD /-10F/ FOR NEW YEARS
EVE AS LOW TEMPERATURES RECOVER TO ABOVE ZERO VALUES.
AT THE END OF THE UPCOMING WEEK...GFS AND ECMWF MODELS FORECAST ANOTHER
WAVE TO DROP SOUTH FROM CANADA...THIS TIME THROUGH THE BASE OF A
HUDSON/JAMES BAY CYCLONE. WHILE TIMING/AMPLITUDE DETAILS ARE A BIT
UP IN THE AIR AT THIS POINT...THE PROGS DO WARRANT INCLUSION OF
20-30 POPS FOR SNOW ON FRIDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1202 PM CST SAT DEC 27 2014
VFR IS IN PLACE FOR MOST OF MN AT TAF ISSUANCE TIME...WITH THE
BACK EDGE OF THE STRATUS NEARING MSP. THE CLEARING WILL PUSH
OVER THE WI TAF SITES THROUGH MID AFTERNOON. NORTHWEST WINDS WILL
BACK SOUTHWEST THIS EVENING...THEN BECOME NORTHWEST AGAIN SUNDAY
BEHIND A COLD FRONT.
KMSP...MVFR CIGS EXPECTED UNTIL ABOUT 19Z...THEN VFR THROUGH MUCH
OF THE PERIOD. COULD SEE SOME MVFR CIGS RETURN SUNDAY AFTERNOON.
/OUTLOOK FOR KMSP/
SUN NIGHT...MVFR POSSIBLE EARLY. WINDS N 5-10 KTS.
MON...VFR. WINDS N 10 KTS.
TUE...VFR. WINDS NW 5-10 KTS
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...MPG
LONG TERM...LS
AVIATION...BORGHOFF
AREA FORECAST DISCUSSION
NWS JACKSON MS
316 PM CST SAT DEC 27 2014
.SHORT TERM...TONIGHT THROUGH SUNDAY NIGHT...WV IMAGERY THIS
AFTERNOON SHOWING MID/UPPER LEVEL SYSTEM CONTINUING TO DIG
SOUTH...NOW ENTERING NW MEXICO. TO THE EAST...MID/UPPER LEVEL
ANTICYCLONE REMAINS NEARLY STATIONARY OVER THE CARRIBEAN. RESULTING
FLOW IN BETWEEN HAS BECOME INCREASINGLY SSW ALLOWING THE MOISTURE
RICH AIR (PWATS NEAR 2 INCHES) OVER THE NW GULF OF MEXICO TO BE
TAPPED.
ALREADY...ELEVATED CONVECTIVE CLUSTERS MOVING OVER SE MS HAVE
PRODUCED SUBSTANTIAL RAINS WITH SPORADIC STREET FLOODING BEING
REPORTED. LATEST HRRR DATA IS INDICATING CONVECTION WILL FILL BACK
IN ALONG THE MID 60 DEWPOINT AXIS...CURRENTLY BISECTING LA...AS IT
MOVES INTO WESTERN MS EARLY THIS EVENING. BELIEVE THE AXIS OF
HEAVIEST RAINS WILL SET UP ALONG THE EASTERN FLANK OF THE DEWPOINT
GRADIENT WHICH WILL OCCUR COINCIDE WITH THE AXIS OF HIGHEST PWAT
COMING IN OFF THE NORTHERN GULF OF MEXICO. THE NAM...HRRR...GFS...
AND ECMWF ALL HAVE SIMILAR QPF SOLUTIONS.
WHILE PWAT VALUES AS HIGH AS WE ARE SEEING IS ANOMALOUS ENOUGH (+3
STANDARD DEVIATIONS)...EVEN MORE AMAZING IS THE FACT THAT THE
MAJORITY OF THE MOISTURE SEEMS TO BE LOCATED BELOW 700 MB WHEN
LOOKING AT AREA SOUNDINGS FROM THIS MORNING AND AFTERNOON. ABOVE 700
MB PROFILES ARE QUITE DRY. THIS HAS ALLOWED FOR CONVECTIVE
DESTABILIZATION AS MOISTURE CONTINUES TO STREAM IN AND IS MOST
LIKELY RESPONSIBLE FOR THE ELEVATED STORMS WITH HAIL THAT WE ARE
CURRENTLY SEEING. BELIEVE THIS WILL CONTINUE TO BE A PROBLEM TONIGHT
UNTIL THE COLUMN CAN BECOME SUBSTANTIALLY SATURATED. WILL CONTINUE
TO OUTLOOK OUR LIMITED SEVERE THREAT...BUT MOVE IT A LITTLE FURTHER
NORTH BASED ON CURRENT TRENDS. THERE STILL APPEARS TO BE A LIMITED
TORNADO THREAT OVER THE SOUTHERN FRINGES OF THE FORECAST AREA WHERE
MORE IN THE WAY OF SURFACE BASED CONVECTION CAN GET GOING.
FRONTAL BOUNDARY MOVING THROUGH AFTER MIDNIGHT WILL ALLOW RAINFALL
TO WANE SOMEWHAT. HOWEVER...DO EXPECT IT TO BREAK OUT AGAIN SUNDAY
AS WHATS LEFT OF PHASING MID LEVEL WAVE WORKS ITS WAY THROUGH.
RAINFALL WILL TAPER OFF RAPIDLY AFTER MIDNIGHT SUNDAY NIGHT./26/
.LONG TERM...MONDAY THROUGH SATURDAY...SURFACE HIGH PRESSURE RIDGING
WILL BUILD IN ON MONDAY ACROSS THE ARKLAMISS WITH COOLER HIGHS
RANGING FROM THE LOW TO MID 50S. LITTLE CHANGE IS EXPECTED TUESDAY...
BUT COLDER AIR WILL MOVE IN TUESDAY NIGHT AS COLD HIGH PRESSURE NOSES
INTO THE REGION. NEW YEARS EVE DAY TEMPERATURES WILL ONLY CLIMB INTO
THE 40S AND LOWER 50S. NEW YEARS EVE WILL BE COLD WITH LOWS WEDNESDAY
NIGHT FALLING INTO THE UPPER 20S/LOW 30S.
THE PATTERN OVER THE AREA WILL BEGIN TO CHANGE ON THURSDAY AS THE
SURFACE HIGH SHIFTS TO THE EAST AND AN UPPER TROUGH DEEPENS OVER THE
SOUTHERN PLANES. MOISTURE WILL INCREASE OVER THE AREA THURSDAY NIGHT
INTO FRIDAY WITH SHOWERS ON THE INCREASE FRIDAY AFTERNOON. THE
GLOBAL MODELS DIVERGE ON THEIR SOLUTIONS FRIDAY NIGHT INTO SATURDAY
WITH THE GFS TAKING THE SURFACE LOW NORTH AND THE ECMWF FURTHER
SOUTH. EITHER WAY SHOWERS AND STORMS WILL BE ON THE INCREASE AS WE
GET INTO THE WEEKEND WITH ANOTHER ROUND OF HEAVY RAINFALL AND
POSSIBLY SOME SEVERE STORMS./15/26/
&&
.AVIATION...LOW MVFR TO IFR CIGS NOW COVER AREA. TSRA WITH VERY
HEAVY RAIN MOVING THROUGH PINE BELT REGION HAS BEEN LOWERING VSBYS
TO LESS THAN 1SM AT TIMES AT KHBG THIS AFTERNOON. MORE OF THIS SORT
OF ACTIVITY WILL MOVE INTO KHBG AREA AFTER 22Z...AS WELL AS POTENTIALLY
IMPACT KGLH/KGWO/KHKS TOWARD 00Z. OVERALL...IFR CIGS WITH OCCASIONAL IFR
VSBYS/LIFR CIGS IN SHRA/TSRA WILL BE THE RULE TONIGHT AT ALL TAF
SITES. RAINFALL WILL TAPER OFF SOMEWHAT FROM WEST TO EAST 09Z TO 15Z
AS COLD FRONT SLOWLY MOVES EAST ACROSS REGION. WINDS WILL SHIFT TO THE
NW/N AFTER FROPA...AND BECOME GUSTY IN THE DELTA REGION AS STRONG HIGH
PRESSURE BUILDS INTO THE REGION. IFR/LOW MVFR CIGS WILL PERSIST IN THE
WAKE OF THE FRONT THROUGH AT LEAST 18Z. /AEG/
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 52 54 42 53 / 100 97 94 8
MERIDIAN 58 62 45 56 / 100 94 95 14
VICKSBURG 48 50 40 52 / 100 98 89 6
HATTIESBURG 62 67 48 59 / 100 63 82 7
NATCHEZ 50 52 41 53 / 100 95 87 5
GREENVILLE 43 46 37 50 / 100 89 75 7
GREENWOOD 46 48 39 51 / 100 96 85 9
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...FLASH FLOOD WATCH THROUGH SUNDAY AFTERNOON FOR MSZ026>033-
036>039-042>066-072>074.
LA...FLASH FLOOD WATCH THROUGH SUNDAY AFTERNOON FOR LAZ026.
AR...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1237 PM CST SAT DEC 27 2014
.UPDATE...
ISSUED AT 1236 PM CST SAT DEC 27 2014
AREA OF LIGHT SNOW CONTINUES TO PUSH EAST OF THE VALLEY...AND
TIMING STILL LOOKS GOOD FOR MOVING IT OUT OF THE AREA BY 21Z.
THUS...WILL NOT MAKE ANY CHANGES FOR POPS/PCPN ATTM. REST OF
FORECAST CONTINUES TO LOOK GOOD.
UPDATE ISSUED AT 935 AM CST SAT DEC 27 2014
AREA OF LIGHT SNOW CONTINUES TO PUSH ACROSS THE NRN VALLEY SO WILL
KEEP POPS/PCPN AS IS FOR NOW. OTHERWISE...REST OF FORECAST ON
TARGET.
UPDATE ISSUED AT 710 AM CST SAT DEC 27 2014
WEAK RETURNS ASSOCIATED WITH LIGHT SNOW WHICH HAS MOVED ACROSS THE
HWY 2 CORRIDOR THE LAST 4 HOURS IS WEAKENING AS IT MOVES INTO THE
CWA...HOWEVER WE ARE SEEING REPORTS OF LIGHT SNOW (LIKELY
FLURRIES) FROM THE I 94 CORRIDOR NORTH. WILL CONTINUE FLURRIES FOR
AREAS OUTSIDE AREAS DEPICTED ON RADAR AND CONTINUE THE MENTION OF
MEASURABLE SNOW ACROSS THE FAR NORTH UNTIL MORNING SNOW REPORTS
COME IN...AS A TENTH OF AN INCH NOT OUT OF THE QUESTION BUT
CONFIDENCE IS DECREASING WITH LATEST RADAR TRENDS.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 402 AM CST SAT DEC 27 2014
SKY COVER AND RELATED TEMPERATURES WILL BE THE FORECAST CHALLENGE
FOR TODAY AND TONIGHT. EASTERN NORTH DAKOTA IS CURRENTLY SEEING AN
INCREASE IN CLOUD COVER AND FILLING IN A BAND OF CLEAR SKIES FROM
ABOUT THE RRV TO DEVILS LAKE. THAN NAM12 AND RUC13 MODELS ARE
DOING A DECENT JOB DEPICTING THE CLEAR BAND AND USED THOSE MODELS
FOR GUIDANCE. ANOTHER CHALLENGE WILL BE ASSOCIATED LIGHT SNOW OR
FLURRIES AS SOME WEAK VORTICES MOVE ACROSS SRN CANADA.
TODAY...LOW CLOUDS TO THE EAST WILL PROGRESS SLOWER THAN THE
CLOUDS MOVING IN FROM THE WEST AND FILL IN THE CLEAR GAP OVER
NORTHEASTERN ND BY MID MORNING. SOME LIGHT SNOW NOW JUST EAST OF
MINOT WILL TRACK ACROSS NORTHERN ND AND INTO N CNTRL MN...AND
MODELS ARE SHOWING THIS MOVING EAST OF CWA BY 21Z. HAVE INTRODUCED
SOME LOW POPS AND ISOLATED SHSN FOR THIS AS WV IS SHOWING A COUPLE
OF WAVES MOVING ACROSS SRN CANADA THAT ARE PROVIDING ENOUGH LIFT
TO GENERATE SOME LIGHT SNOW. EXPECT NO MORE THAN A COUPLE OF
TENTHS OF AN INCH OF FLUFF ACROSS THE FAR NORTH...AND RATHER
SPOTTY IN NATURE. SOUTHERN ZONES WILL BE MORE CHALLENGING AS SAT
TRENDS DO NOT GIVE ME A LOT OF CONFIDENCE THAT THE SRN VALLEY WILL
SEE CLOUDS MOVE IN...AND IF IT REMAINS CLEAR COULD BE WARMER THAN
FCST HIGHS.
TONIGHT...AN ARCTIC AIRMASS WILL BEGIN SINKING SOUTH AND THE DRIER
AIR SHOULD HELP CLEAR THINGS OUT AT LEAST IN THE NORTH. WILL SEE A
LARGE TEMP GRADIENT ACROSS CWA FROM NW TO SE AS LINGERING CLOUDS
IN THE FAR SE COULD KEEP OVERNIGHT LOWS IN THE LOW TEENS WHEREAS
THE NW SHOULD SEE TEMPS FALL INTO DOUBLE DIGITS BELOW ZERO AS THE
COLD AIRMASS DROPS INTO THE REGION.
SUNDAY...ARCTIC AIR MASS SINKING SOUTH WILL BRING AN INCREASE IN
SOLAR BUT MUCH COLDER AND DRIER AIR. DAYTIME HIGHS WILL STRUGGLE
TO RECOVER TO ABOVE ZERO TEMPS ACROSS THE NORTH...WHILE THE
SOUTHERN ZONES WILL LIKELY SEE EARLY HIGHS AS EARLY MORNING CLOUDS
KEEP SAT NIGHT LOWS IN THE MID TEENS PRIOR TO COLDER AIR MAKING IT
TO THE SOUTHERN ZONES. SHOULD SEE STEADY TO FALLING TEMPS IN THE AFTN.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 402 AM CST SAT DEC 27 2014
SUNDAY NIGHT THROUGH MONDAY NIGHT...SFC HIGH WILL MOVE OVER MT AND
DAKOTAS AND MN SHOULD SEE LIGHT NW FLOW...WHICH WILL KEEP MON
NIGHT LOWS FROM PLUMMETING TOO FAR BUT DOUBLE DIGITS BELOW ZERO
TEMPS ARE EXPECTED. ADDITIONALLY THE LIGHT NW WINDS WILL BE
SUFFICIENT TO BRING WIND CHILLS TO ADVISORY LEVELS BOTH MON AND
TUE MORNING. THE COLD APPARENT TEMPS BOTH MORNINGS WILL BE THE
MOST SIGNIFICANT WX HAZARD WITHIN THE SHORT TERM PERIOD.
WEDNESDAY THROUGH SATURDAY...THE DEEP LONG WAVE TROF OVER CENTRAL NOAM
EARLY IN THE WEEK SHOWS A DISTINCT SHIFT INTO THE EAST AT MIDWEEK
AND A RETURN TO A MORE ZONAL FLOW PATTERN ACROSS THE NORTHERN
PLAINS BY THE LATE WEEK PERIOD. EXPECT ARCTIC AIRMASS TO MODERATE
TO NEAR SEASONAL NORMALS WED INTO FRI...WITH AN ADDITIONAL SHOT OF
COLD AIR MOVING IN BY THE WEEK END. PRECIPITATION CHANCES ARE LOW
THROUGH THE PERIOD WITH OCCASIONAL LIGHT SNOW OR FLURRIES
POSSIBLE LATE THURSDAY INTO SATURDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1236 PM CST SAT DEC 27 2014
BRIEF BAND OF -SN JUST ABOUT THROUGH KGFK...VFR CIGS SHOULD
PREVAIL AT ALL SITES THROUGH THE AFTERNOON. COLD FRONT ON A MAINLY
NORTH TO SOUTH TRACK THROUGH REGION LATER TODAY THIS AFTN WILL
LIKELY BE ACCOMPANIED BY SEVERAL HOURS OF MVFR...INCLUDED -SHSN
ALL EXCEPT KFAR AT AND BEYOND FROPA. WINDS TO SHIFT TO N-NW BEHIND
FRONT REMAINING ARD 10 KTS.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...HOPKINS
SHORT TERM...SPEICHER
LONG TERM...GUST/SPEICHER
AVIATION...WJB
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
1245 PM EST SAT DEC 27 2014
.SYNOPSIS...
LOW PRESSURE WILL MOVE ACROSS THE GREAT LAKES TODAY AND DRAG A
COLD FRONT ACROSS THE AREA LATE TODAY AND TONIGHT. A SECOND COLD
FRONT IS EXPECTED LATE MONDAY INTO TUESDAY. HIGH PRESSURE FROM
CANADA WILL BUILD IN FOR WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE INITIAL WAVE OF PRECIPITATION IN ADVANCE OF THE COLD FRONT HAS
BECOME WIDELY SCATTERED AND LIGHT OVER THE FORECAST AREA. WITH THE
FRONT STILL WELL TO THE WEST AND THE LACK OF SUPPORT...I EXPECT THIS
TREND TO CONTINUE. I WILL PULL BACK THE POPS FOR THIS AFTERNOON
PARTICULARLY OVER THE EASTERN SECTIONS OF THE AREA. SHOWERS WILL
BE IN THE AREA BUT WILL REMAIN WIDELY SCATTERED. A LITTLE BETTER
CHANCE FOR PRECIP OVER THE WESTERN COUNTIES BUT I WILL REDUCE THE
POPS SLIGHTLY IN THAT AREA AS WELL. I EXPECT THE BULK OF THE
PRECIPITATION WITH THE FRONTAL PASSAGE 00Z-06Z TIME FRAME. SOME
SUN OVER THE EASTERN PARTS OF THE FORECAST AREA ARE ALLOWING
TEMPERATURES TO QUICKLY RISE INTO THE 50S. SLIGHT WARM AIR
ADVECTION IN THIS AREA WILL ALLOW TEMPERATURES TO CONTINUE TO
RISE. 15Z RUC PUSHES TEMPERATURES INTO THE MID 50S FOR SEVERAL
LOCATIONS. I WILL RAISE TEMPERATURES A FEW DEGREES OVER THE EAST.
PREVIOUS DISCUSSION...
FIRST BAND OF PRECIP JUST WEST OF THE AREA SHOULD MOVE THROUGH
WEST TO EAST THIS MORNING AND EARLY THIS AFTERNOON...POSSIBLY
BECOMING MORE SPOTTY EAST AS SURFACE LOW MOVES FURTHER NORTHEAST
OVER THE CENTRAL GREAT LAKES. BEHIND THE BAND SHOULD COME A BIT OF
A BREAK IN THE PRECIP. LATE THIS AFTERNOON AND EVENING EXPECTING
NOW ANOTHER SURGE OF MOISTURE/PRECIP OUT OF THE SOUTHWEST AHEAD OF
THE COLD FRONT. THIS SHOULD SPREAD RAIN ACROSS THE ENTIRE AREA
FIRST HALF OF THE NIGHT AFTER WHICH WE SHOULD SEE DRYING FROM THE
NORTHWEST WITH DRY AIR AND SUBSIDENCE BEHIND THE FRONT. ADJUSTED
GRIDS TODAY AND TONIGHT TO REFLECT THIS.
ORIGINAL...LOW PRESSURE WILL MOVE NORTHEAST ACROSS THE GREAT
LAKES TODAY. A COLD FRONT ASSOCIATED WITH THE LOW WILL MOVE
THROUGH THE AREA THIS EVENING AND OVERNIGHT. MODELS DIFFER A BIT
ON TIMING OF THE PRECIP WITH THE GFS AHEAD OF THE NAM INITIALLY.
WILL SIDE CLOSER TO THE GFS HERE AND BRING CHANCE POPS INTO THE
WEST THIRD THROUGH THE MORNING. FOR THE AFTERNOON WILL INCREASE
POPS WEST TO LIKELY WITH CHANCE POPS MOST ELSEWHERE. HIGHS AROUND
50 REASONABLE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/...
COLD FRONT CONTINUES SOUTHEAST THROUGH THE AREA OVERNIGHT. MODEL
DIFFERENCES CONTINUE WITH THE NAM BECOMING FASTER THAN THE GFS BY
SUNDAY MORNING...TAKING THE MOISTURE SOUTHEAST OUT OF THE AREA
WHILE THE GFS HANGS IT UP ACROSS THE SOUTHEAST THIRD OF THE AREA.
FEEL THAT MOISTURE WILL EXIT THE AREA QUICKLY BUT ALSO LIKELY
PRUDENT TO LEAVE A SMALL CHANCE POP THROUGH THE MORNING SUNDAY
SOUTHEAST BEFORE DRYING OUT COMPLETELY. PTYPE COULD BE AN ISSUE
WITH PRECIP POSSIBLE MIXING/CHANGING JUST BEFORE OR AS IT ENDS BUT
FOR NOW WILL LEAVE AS MOSTLY RAIN. SUNDAY SHOULD REMAIN DRY. SOME
CONCERN ABOUT HOW MUCH CLEARING OCCURS. INVERSION STRONG ENOUGH
BUT BUFKIT SHOWS LESS LOW LEVEL MOISTURE AS PREVIOUS EVENTS.
THINKING BEST CHANCE FOR CLEARING WILL BE NORTHWEST THIRD TO HALF
SO WILL HAVE THE AFTERNOON BECOMING PARTLY SUNNY/PARTLY CLOUDY
THERE. BREAKS POSSIBLE ELSEWHERE AS WELL. MONDAY INTO TUESDAY TWO
SYSTEMS COULD AFFECT THE AREA. FIRST IS A COASTAL LOW THAT
DEVELOPS IN THE GULF COAST AND MOVES NORTHEAST UP THE EAST COAST.
THE NAM SUGGESTS WE GET CLIPPED BY THE MOISTURE WHILE THE GFS
KEEPS IT TO OUR EAST. THE MORE PROBABLE SYSTEM TO AFFECT THE AREA
IS A COLD FRONT THAT WILL DROP SOUTH ACROSS THE AREA LATE MONDAY
AND TUESDAY. WOULD EXPECT SOME SNOW SHOWERS WITH THE FRONT WITH
-SOME- LAKE EFFECT BEHIND AS THE COLD AIR DEEPENS. HIGHS IN THE
UPPER 30S TO NEAR 40 SUNDAY...MID 30S MONDAY AND 20S TO NEAR 30 ON
TAP TUESDAY.
&&
.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
HIGH PRESSURE WILL BE SITUATED ACROSS THE MID MISSISSIPPI AND LOWER
OHIO VALLEYS WEDNESDAY WITH LOW PRESSURE OVER HUDSON BAY. THIS IS
FAIRLY WELL AGREED UPON. A COLD FRONT WILL COME DOWN FROM WESTERN
CANADA AND THE NORTHERN PLAINS AND WILL MOVE ACROSS THE GREAT LAKES
IF NOT WEDNESDAY THAN THURSDAY. THIS WILL ALLOW THE GRADUAL
INFILTRATION OF COLDER AIR SOUTH INTO THE AREA WEDNESDAY AND
THURSDAY. AREAS OUTSIDE OF THE TRADITIONAL SNOWBELT SHOULD REMAIN
PRECIP FREE WITH HIGH PRESSURE SOUTH OF THE AREA AND LIMITED
MOISTURE WITH THE FRONT. DEPENDING ON THE AMOUNT OF MOISTURE
AVAILABLE AND EXACT BOUNDARY LAYER FLOW...LAKE EFFECT SNOW SHOWERS
POSSIBLE. WILL KEEP THE LOW CHANCE MENTION FOR NOW WEDNESDAY.
FORECAST GETS MORE COMPLICATED GOING INTO THE WEEKEND. OPERATIONAL
RUNS OF THE GFS AND ECMWF SHOW THE BEGINNINGS OF THE DEVELOPMENT OF
LOW PRESSURE THAT WOULD TRACK INTO THE OHIO VALLEY SATURDAY. THAT
WOULD BRING A SLIGHT MODIFICATION OF TEMPERATURES FRIDAY AND
THE POSSIBILITY OF PRECIPITATION EXPANDING NORTH INTO THE AREA. A
LOT OF VARIABILITY WITH THIS AND THE GFSENS AND ECMWF ENS BOTH HAVE
LOW PRESSURE FURTHER WEST AT 12Z SAT. THEREFORE WAITED UNTIL FRIDAY
NIGHT TO BRING THE CHANCE OF PRECIP INTO THE AREA. PRECIP TYPE MAY
BE A CONCERN.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
A COLD FRONT WILL APPROACH FROM THE WEST TONIGHT AND BRING A
CHANCE OF RAIN TAPERING TO WIDELY SCATTERED SHOWERS BY MORNING.
I ANTICIPATE THE CONDITIONS TO BECOME MAINLY MVFR TURNING TO
POSSIBLY TO IFR CONDITIONS THIS EVENING AND CONTINUING OVERNIGHT.
SOME WESTERN OHIO TAF SITES ARE ALREADY MVFR WITH MORE MVFR/IFR
CONDITIONS READY TO MOVE INTO THE FORECAST AREA OF OHIO AND NW
PENNSYLVANIA THIS EVENING.
WINDS SOUTHWEST THIS EVENING AND THEN WEST-NORTHWEST AFTER THE
FRONTAL PASSAGE WHICH IS EXPECTED BETWEEN 00Z SUN AND 09Z SUN.
.OUTLOOK...NON-VFR EXITING SUNDAY. NON-VFR MAINLY OVER NE OH/NW
PA MONDAY...THEN POSSIBLY MORE NON-VFR CONDITIONS OVER THE
ENTIRE AREA TUESDAY. WEDNESDAY NON-VFR POSSIBLE JUST ACROSS NE
OH/NW PA.
&&
.MARINE...
SOUTHERLY FLOW ON THE LAKE WILL TURN MORE SOUTHWESTERLY AND THEN
WEST-NORTHWEST TONIGHT WITH THE PASSAGE OF A COLD FRONT. WINDS
INCREASE ENOUGH FOR A SMALL CRAFT ADVISORY FOR THE EASTERN TWO
THIRDS THROUGH MIDDAY SUNDAY. A RIDGE BUILDS OVER THE LAKE QUICKLY
ON SUNDAY DIMINISHING WINDS/WAVES. AN EXPANSIVE AREA OF HIGH
PRESSURE WILL SHIFT FROM WESTERN CANADA TO THE CENTRAL PLAINS MONDAY
THROUGH WEDNESDAY. MEANWHILE LOW PRESSURE WILL BE MAKING ITS WAY
SOUTH TO HUDSON BAY WEDNESDAY...INCREASING GRADIENT BETWEEN THE TWO
FEATURES. THEREFORE WEST TO SOUTHWEST WINDS WILL INCREASE ON THE
LAKE. SMALL CRAFT ADVISORIES LIKELY AGAIN FOR MID WEEK.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 10 AM EST
SUNDAY FOR LEZ147>149.
&&
$$
SYNOPSIS...TK
NEAR TERM...GARNET/TK
SHORT TERM...TK
LONG TERM...OUDEMAN
AVIATION...BC
MARINE...OUDEMAN
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
1220 PM EST SAT DEC 27 2014
.SYNOPSIS...
LOW PRESSURE WILL MOVE ACROSS THE GREAT LAKES TODAY AND DRAG A
COLD FRONT ACROSS THE AREA LATE TODAY AND TONIGHT. A SECOND COLD
FRONT IS EXPECTED LATE MONDAY INTO TUESDAY. HIGH PRESSURE FROM
CANADA WILL BUILD IN FOR WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE INITIAL WAVE OF PRECIPITATION IN ADVANCE OF THE COLD FRONT HAS
BECOME WIDELY SCATTERED AND LIGHT OVER THE FORECAST AREA. WITH THE
FRONT STILL WELL TO THE WEST AND THE LACK OF SUPPORT...I EXPECT THIS
TREND TO CONTINUE. I WILL PULL BACK THE POPS FOR THIS AFTERNOON
PARTICULARLY OVER THE EASTERN SECTIONS OF THE AREA. SHOWERS WILL
BE IN THE AREA BUT WILL REMAIN WIDELY SCATTERED. A LITTLE BETTER
CHANCE FOR PRECIP OVER THE WESTERN COUNTIES BUT I WILL REDUCE THE
POPS SLIGHTLY IN THAT AREA AS WELL. I EXPECT THE BULK OF THE
PRECIPITATION WITH THE FRONTAL PASSAGE 00Z-06Z TIME FRAME. SOME
SUN OVER THE EASTERN PARTS OF THE FORECAST AREA ARE ALLOWING
TEMPERATURES TO QUICKLY RISE INTO THE 50S. SLIGHT WARM AIR
ADVECTION IN THIS AREA WILL ALLOW TEMPERATURES TO CONTINUE TO
RISE. 15Z RUC PUSHES TEMPERATURES INTO THE MID 50S FOR SEVERAL
LOCATIONS. I WILL RAISE TEMPERATURES A FEW DEGREES OVER THE EAST.
PREVIOUS DISCUSSION...
FIRST BAND OF PRECIP JUST WEST OF THE AREA SHOULD MOVE THROUGH
WEST TO EAST THIS MORNING AND EARLY THIS AFTERNOON...POSSIBLY
BECOMING MORE SPOTTY EAST AS SURFACE LOW MOVES FURTHER NORTHEAST
OVER THE CENTRAL GREAT LAKES. BEHIND THE BAND SHOULD COME A BIT OF
A BREAK IN THE PRECIP. LATE THIS AFTERNOON AND EVENING EXPECTING
NOW ANOTHER SURGE OF MOISTURE/PRECIP OUT OF THE SOUTHWEST AHEAD OF
THE COLD FRONT. THIS SHOULD SPREAD RAIN ACROSS THE ENTIRE AREA
FIRST HALF OF THE NIGHT AFTER WHICH WE SHOULD SEE DRYING FROM THE
NORTHWEST WITH DRY AIR AND SUBSIDENCE BEHIND THE FRONT. ADJUSTED
GRIDS TODAY AND TONIGHT TO REFLECT THIS.
ORIGINAL...LOW PRESSURE WILL MOVE NORTHEAST ACROSS THE GREAT
LAKES TODAY. A COLD FRONT ASSOCIATED WITH THE LOW WILL MOVE
THROUGH THE AREA THIS EVENING AND OVERNIGHT. MODELS DIFFER A BIT
ON TIMING OF THE PRECIP WITH THE GFS AHEAD OF THE NAM INITIALLY.
WILL SIDE CLOSER TO THE GFS HERE AND BRING CHANCE POPS INTO THE
WEST THIRD THROUGH THE MORNING. FOR THE AFTERNOON WILL INCREASE
POPS WEST TO LIKELY WITH CHANCE POPS MOST ELSEWHERE. HIGHS AROUND
50 REASONABLE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/...
COLD FRONT CONTINUES SOUTHEAST THROUGH THE AREA OVERNIGHT. MODEL
DIFFERENCES CONTINUE WITH THE NAM BECOMING FASTER THAN THE GFS BY
SUNDAY MORNING...TAKING THE MOISTURE SOUTHEAST OUT OF THE AREA
WHILE THE GFS HANGS IT UP ACROSS THE SOUTHEAST THIRD OF THE AREA.
FEEL THAT MOISTURE WILL EXIT THE AREA QUICKLY BUT ALSO LIKELY
PRUDENT TO LEAVE A SMALL CHANCE POP THROUGH THE MORNING SUNDAY
SOUTHEAST BEFORE DRYING OUT COMPLETELY. PTYPE COULD BE AN ISSUE
WITH PRECIP POSSIBLE MIXING/CHANGING JUST BEFORE OR AS IT ENDS BUT
FOR NOW WILL LEAVE AS MOSTLY RAIN. SUNDAY SHOULD REMAIN DRY. SOME
CONCERN ABOUT HOW MUCH CLEARING OCCURS. INVERSION STRONG ENOUGH
BUT BUFKIT SHOWS LESS LOW LEVEL MOISTURE AS PREVIOUS EVENTS.
THINKING BEST CHANCE FOR CLEARING WILL BE NORTHWEST THIRD TO HALF
SO WILL HAVE THE AFTERNOON BECOMING PARTLY SUNNY/PARTLY CLOUDY
THERE. BREAKS POSSIBLE ELSEWHERE AS WELL. MONDAY INTO TUESDAY TWO
SYSTEMS COULD AFFECT THE AREA. FIRST IS A COASTAL LOW THAT
DEVELOPS IN THE GULF COAST AND MOVES NORTHEAST UP THE EAST COAST.
THE NAM SUGGESTS WE GET CLIPPED BY THE MOISTURE WHILE THE GFS
KEEPS IT TO OUR EAST. THE MORE PROBABLE SYSTEM TO AFFECT THE AREA
IS A COLD FRONT THAT WILL DROP SOUTH ACROSS THE AREA LATE MONDAY
AND TUESDAY. WOULD EXPECT SOME SNOW SHOWERS WITH THE FRONT WITH
-SOME- LAKE EFFECT BEHIND AS THE COLD AIR DEEPENS. HIGHS IN THE
UPPER 30S TO NEAR 40 SUNDAY...MID 30S MONDAY AND 20S TO NEAR 30 ON
TAP TUESDAY.
&&
.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
HIGH PRESSURE WILL BE SITUATED ACROSS THE MID MISSISSIPPI AND LOWER
OHIO VALLEYS WEDNESDAY WITH LOW PRESSURE OVER HUDSON BAY. THIS IS
FAIRLY WELL AGREED UPON. A COLD FRONT WILL COME DOWN FROM WESTERN
CANADA AND THE NORTHERN PLAINS AND WILL MOVE ACROSS THE GREAT LAKES
IF NOT WEDNESDAY THAN THURSDAY. THIS WILL ALLOW THE GRADUAL
INFILTRATION OF COLDER AIR SOUTH INTO THE AREA WEDNESDAY AND
THURSDAY. AREAS OUTSIDE OF THE TRADITIONAL SNOWBELT SHOULD REMAIN
PRECIP FREE WITH HIGH PRESSURE SOUTH OF THE AREA AND LIMITED
MOISTURE WITH THE FRONT. DEPENDING ON THE AMOUNT OF MOISTURE
AVAILABLE AND EXACT BOUNDARY LAYER FLOW...LAKE EFFECT SNOW SHOWERS
POSSIBLE. WILL KEEP THE LOW CHANCE MENTION FOR NOW WEDNESDAY.
FORECAST GETS MORE COMPLICATED GOING INTO THE WEEKEND. OPERATIONAL
RUNS OF THE GFS AND ECMWF SHOW THE BEGINNINGS OF THE DEVELOPMENT OF
LOW PRESSURE THAT WOULD TRACK INTO THE OHIO VALLEY SATURDAY. THAT
WOULD BRING A SLIGHT MODIFICATION OF TEMPERATURES FRIDAY AND
THE POSSIBILITY OF PRECIPITATION EXPANDING NORTH INTO THE AREA. A
LOT OF VARIABILITY WITH THIS AND THE GFSENS AND ECMWF ENS BOTH HAVE
LOW PRESSURE FURTHER WEST AT 12Z SAT. THEREFORE WAITED UNTIL FRIDAY
NIGHT TO BRING THE CHANCE OF PRECIP INTO THE AREA. PRECIP TYPE MAY
BE A CONCERN.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
FIRST WAVE OF SHOWERS TO WORK ACROSS THE AREA THIS MORNING AND
LAST ABOUT 2-3 HOURS. UNSURE HOW FAR EAST THEY WILL GET...POSSIBLY
DRYING UP BEFORE THEY REACH THE EASTERN TAF SITES. COULD SEE SOME
MVFR WITH THESE. VFR FOR THE MIDDLE PORTION OF THE DAY EXCEPT FOR
KTOL/KFDY. FOR TONIGHT COLD FRONT CROSSES. EXPECT SHOWERS WITH
WIDESPREAD MVFR CONDITIONS AND AREAS OF IFR TO SPREAD FROM WEST TO
EAST STARTING LATE THIS AFTERNOON FOR KTOL AND KFDY. THESE SHOWERS
WILL BE PROGRESSIVE AS WELL AND WILL BE EXITING THE AREA CLOSE TO
12Z SUN. SOUTHERLY WINDS THIS MORNING WILL VEER SOUTHWEST AND THEN
WEST- NORTHWEST AFTER THE FRONTAL PASSAGE WHICH IS EXPECTED
BETWEEN 00Z SUN AND 09Z SUN.
.OUTLOOK...NON-VFR EXITING SUNDAY. NON-VFR MAINLY OVER NE OH/NW
PA MONDAY...THEN POSSIBLY OVER THE ENTIRE AREA TUESDAY. WEDNESDAY
NON-VFR POSSIBLE ACROSS NE OH/NW PA.
&&
.MARINE...
SOUTHERLY FLOW ON THE LAKE WILL TURN MORE SOUTHWESTERLY AND THEN
WEST-NORTHWEST TONIGHT WITH THE PASSAGE OF A COLD FRONT. WINDS
INCREASE ENOUGH FOR A SMALL CRAFT ADVISORY FOR THE EASTERN TWO
THIRDS THROUGH MIDDAY SUNDAY. A RIDGE BUILDS OVER THE LAKE QUICKLY
ON SUNDAY DIMINISHING WINDS/WAVES. AN EXPANSIVE AREA OF HIGH
PRESSURE WILL SHIFT FROM WESTERN CANADA TO THE CENTRAL PLAINS MONDAY
THROUGH WEDNESDAY. MEANWHILE LOW PRESSURE WILL BE MAKING ITS WAY
SOUTH TO HUDSON BAY WEDNESDAY...INCREASING GRADIENT BETWEEN THE TWO
FEATURES. THEREFORE WEST TO SOUTHWEST WINDS WILL INCREASE ON THE
LAKE. SMALL CRAFT ADVISORIES LIKELY AGAIN FOR MID WEEK.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 10 AM EST
SUNDAY FOR LEZ147>149.
&&
$$
SYNOPSIS...TK
NEAR TERM...GARNET/TK
SHORT TERM...TK
LONG TERM...OUDEMAN
AVIATION...OUDEMAN
MARINE...OUDEMAN
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
534 PM EST SAT DEC 27 2014
.SYNOPSIS...
A SERIES OF SMALL LOW PRESSURE WILL MOVE NORTHEAST ALONG A COLD
FRONT AS THE FRONT SLOWLY CROSSES OUR REGION FROM THE WEST THROUGH
MONDAY. COOLER HIGH PRESSURE WILL BUILD OVER OUR REGION IN THE MID
TO LATTER PART OF THE WEEK. ANOTHER LOW PRESSURE WILL GET ORGANIZED
OVER TEXAS AND REACH OUR AREA NEXT WEEKEND.
&&
.NEAR TERM /THROUGH SUNDAY/...
AS OF 515 PM...LIGHT AND HIGH RADAR RETURNS WERE TRACKING ACROSS NRN
GA. THESE RETURNS HAVE NOT BEEN ASSOCIATED WITH SFC OBS OF
RAIN...EXPECTING RETURNS FROM VIRGA. HOWEVER...A LARGE PATCH OF
LIGHT RAIN WAS DRIFTING ACROSS THE AL/GA LINE...THIS AREA SHOULD
RESULT IN RAIN ACROSS THE CWA LATER TONIGHT. I WILL UPDATE TO ADJUST
POP TIMING AND ALIGN TEMP/DWPT WITH OBSERVATIONS.
AS OF 240 PM EST SATURDAY...THE LATEST SATELLITE IMAGE SHOWS A DEEP
AND MOIST WARM CONVEYOR BELT EXTENDING FROM THE GREAT LAKES REGION
DOWN TO THE WESTERN GULF...AND TO THE EASTERN PACIFIC...WITH BROAD
AREAS OF CONVECTION DEVELOPING ACROSS THE DEEP SOUTH AS OF THIS
AFTERNOON HOURS. AS AN EASTERN CONUS UPPER RIDGE AXIS PUSHES OFF THE
ATLANTIC COAST AND MOIST SWLY FLOW ALOFT SETS UP OVER THE SOUTHEAST
US...MID TO LOW LEVEL CLOUDS WILL SPREAD OVER THE PIEDMONT THROUGH
THE AFTERNOON HOURS.THE LATEST SHORT TERM MODELS CONTINUE TO
INDICATE THAT A COLD FRONT WILL SLOWLY MOVE EAST ACROSS THE
MISSISSIPPI VALLEY AND INTO THE TN VALLEY TONIGHT INTO SUN
MORNING...REACHING THE SOUTHERN APPALACHIANS BY SUN AFTERNOON. AHEAD
OF THIS FRONT...A DEEP PLUME OF GULF MOISTURE WILL BE DRAWN UP INTO
THE REGION AS A WAVE OF LOW OVER THE WESTERN GULF LIFTS NE ACROSS
AL/MI TONIGHT. THEREFORE...POPS QUICKLY RAMP UP FROM WEST TO EAST
INTO THE CATEGORICAL RANGE OVER THE WESTERN MTNS ZONES AND NE
GA...WITH LIKELY RANGE OVER THE REST OF THE WESTERN HALF OF THE CWA.
THE BEST RAINFALL RATES WILL OCCUR BETWEEN 12Z-18Z SUN WHEN THE
SURFACE WAVE OF LOW LIFTS NE ACROSS THE CWA AND A SERIES OF UPPER
DISTURBANCES RIPPLES ACROSS THE MTNS ZONES IN SWLY FLOW ALOFT.
ALSO...HAVE MENTIONED A CHANCE OF THUNDER ACROSS MUCH OF THE REGION
EARLY SUN AFTERNOON DUE TO THE PRESENCE OF 100-200J/KG MUCAPE PER
LATEST NAM/GFS/ECMWF. POPS RAMP DOWN TO THE LIKELY RANGE OVER THE
MTN ZONES AND SOLD CHANCE RANGE OVER THE SOUTHERN TIER OF THE REGION
18Z THRU 00Z MON AS THE UPPER FORCING AND THE SURFACE WAVE OF LOW
MOVES OFF TO THE NE. WITH MODELS TRENDING A BIT WETTER FOR THE
UPCOMING EVENT...HAVE GONE WITH THE HPC QPF GUIDANCE RESULTING IN
0.75-1.0" OVER THE WESTERN NC MTNS AND NE GA... WITH AROUND
0.25-0.5" ELSEWEHRE THRU SUN EVENINING.
WITH CONSIDERABLE CLOUD COVER AND WAA SOUTHERLY FLOW...OVERNIGHT
TEMPS WILL STAY 7-10 DEGREES ABOVE NORMAL. WITH ONGOING
PRECIP...AFTERNOON HIGHS ON SUN WILL BE AROUND 3-5 DEGREES COOLER
THAN TODAY.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
AS OF 200 PM SATURDAY...THE MODELS SUGGEST THAT WE WILL BE IN A LULL
OF SORTS AT THE START OF THE SHORT RANGE PERIOD SUNDAY EVENING...AS
WE WILL BE IN A MINIMUM OF FORCING. THAT CHANGES QUICKLY BY LATE
EVENING AS THE RIGHT ENTRANCE REGION OF THE UPPER JET TRANSLATES
OVERHEAD BETWEEN ROUGHLY 03Z AND 09Z...AND THE MAIN SHORT WAVE AXIS
MOVES THROUGH IN THE 06Z TO 12Z MONDAY TIME FRAME. ALTHO THE WAVE
SHEARS AND DEAMPLIFIES AS IT CROSSES THE REGION...THE FORCING SHOULD
STILL BE SUFFICIENT TO INCREASE PRECIP PRODUCTION...COMBINED WITH
IMPROVED MOIST ISENTROPIC LIFT. SO...PRECIP CHANCES RAMP BACK UP TO
CATEGORICAL MAINLY OVER THE AREA ALONG AND N/W OF I-85...AND LIKELY
TO THE S...BY 06Z OR SO. THE MAIN FORCING SHOULD SHIFT E OF THE AREA
MONDAY MORNING. THE HIGHEST PRECIP PROBABILITY WILL BE OVER THE WRN
NC PIEDMONT ON MONDAY MORNING. POP WAS LIMITED TO LIKELY OUT OF
UNCERTAINTY WITH TIMING THE DEPARTURE OF THE FORCING...BUT COULD
EASILY HAVE TO BE KEPT CATEGORICAL BEYOND 12Z MONDAY WITH THE
SLIGHTEST DELAY. THE REST OF MONDAY WILL HAVE A SLOW RAMP DOWN
THROUGH THE CHANCE RANGE AS FORCING GRADUALLY WEAKENS BEHIND THE
SURFACE FRONT THAT CROSSES FIRST THING IN THE DAY. FOR MONDAY NIGHT
AND TUESDAY...THERE IS UNCERTAINTY REGARDING THE EXTENT/CHANCE OF
PRECIP. THE LOW LEVEL FLOW COMES AROUND TO SOMETHING NW MONDAY NIGHT
AND TUESDAY WHICH SHOULD FORCE SOME SHOWER ACTIVITY NEAR THE TN
BORDER. THE PASSAGE OF ANOTHER SHORT WAVE COMBINED WITH SOME LOW
LEVEL FRONTOGENESIS APPEARS TO BE RESPONSIBLE FOR THE REDEVELOPMENT
OF PRECIP ON TUESDAY OFF TO OUR N...WHICH SOME OF THE GUIDANCE
BLEEDS DOWN INTO NC. PREFER TO KEEP THE BETTER CHANCES IN THE
UPSLOPE AREAS OF THE NRN MTNS AND TO KEEP THE AREA E OF THE BLUE
RIDGE DRY FOR THE TIME BEING. TEMPS SHOULD DROP BACK DOWN TO NEAR
NORMAL ON TUESDAY.
ON SUNDAY THE FAIRLY BROAD FRONTAL ZONE WILL
EXTEND FROM QUEBEC SWWD TO THE WRN GULF COAST...BISECTING THE TENN
VALLEY JUST TO OUR WEST. AT LEAST ONE WEAK WAVE IS PROGGED TO RIDE
UP THE FRONT DURING THE DAY AS A RESULT OF CYCLONIC UPPER FLOW OVER
THE BOUNDARY CONTAINING EMBEDDED WEAK VORTICES. THOUGH SUCH A WAVE
WOULD LIKELY PROVIDE LOCAL ENHANCEMENT TO LLVL WARM/MOIST ADVECTION
AHEAD OF THE FRONT...THE EXISTENCE OF ONE IS IN QUESTION GIVEN THE
POOR AGREEMENT AND CONSISTENCY FROM GUIDANCE ON HOW THIS OCCURS.
OVERALL THE FORCING SUNDAY IS JUST NOT ALL THAT IMPRESSIVE. LITTLE
TO NO INSTABILITY IS PROGGED OVER THE CWFA AND THOUGH A GOOD SLUG OF
MOISTURE TRANSPORT IS PRESENT ON NAM/GFS PROGS THE LLVL LIFT IS
LIMITED. AT ANY RATE...THRU SUNDAY THE FRONT REMAINS NEARLY
STATIONARY ACRS THE SOUTHEAST...THE PARENT LOW CONTINUING TO
PROGRESS EWD WITH THE ACTIVE NRN STREAM WHILE THE BROAD SRN STREAM
TROUGH IS HELD OFF BY THE BERMUDA HIGH. IT APPEARS THE FRONT WILL
NOT ACTUALLY ENTER THE AREA UNTIL MONDAY MRNG...WITH A DISTINCT
500MB SHORTWAVE ACCOMPANYING IT AS WELL AS UPPER DIVERGENCE ASSOC
WITH RR QUAD OF A JET STREAK.
TWO PEAKS OF PRECIP ACTIVITY ARE SUGGESTED WHEN THE TOTAL FORCING IS
MAXIMIZED...SUNDAY MRNG AND THEN EARLY MON MRNG. HOWEVER IT IS
DIFFICULT TO PICK OUT A POINT BETWEEN WHERE A LULL SHOULD BE
BETWEEN...WITH THE OVERALL PATTERN REMAINING FAVORABLE FOR AT LEAST
LIGHT PRECIP. WILL CONTINUE TO ADVERTISE LIKELY POPS MOST OF THE AREA
THROUGHOUT SUNDAY...BUT CONCENTRATING MORE QPF CLOSE TO THE
AFOREMENTIONED PEAKS. DESPITE CLOUDS AND RAIN...IN THE WARM AIRMASS
TEMPS SHOULD TOP OUT 5-9 DEGREES ABOVE NORMAL SUN AFTN...WITH MINS
MON MRNG BEING EVEN MORE ABOVE NORMAL...UPPER 40S AND LOWER 50S. MAX
TEMPS MONDAY WILL BE SLIGHTLY WARMER THAN SUNDAY OVER THE PIEDMONT
WITH THE FRONT NOT YET HAVING AN IMPACT.
PROGRESSION OF THE UPPER PATTERN IS STILL PRETTY SLOW THRU MON
NIGHT...WITH THE CWFA NEAR THE INFLECTION POINT BETWEEN THE PLAINS
TROUGH AND THE ATLANTIC RIDGE. POPS DECLINE ONLY GRADUALLY THRU THE
END OF THE PERIOD WITH MOST OF THE GUIDANCE INDICATING SOME QPF
CONTINUING ON THE BACK SIDE OF ANOTHER FRONTAL WAVE DEVELOPING NEAR
THE GA/SC COAST. COLDER AIR WILL BEGIN TO RETURN TO ALL AREAS ON THE
ENSUING NLY FLOW MON NIGHT...THOUGH MIN TEMPS WILL STILL BE AROUND 10
DEGREES ABOVE CLIMO.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
AS OF 215 PM SATURDAY...THE MEDIUM RANGE WILL START OUT WITH SPLIT
UPPER LVL FLOW...WITH A LARGE POLAR VORTEX SPINNING OVR HUDSON
BAY...AND A CUTOFF LOW INVOF CALIFORNIA. THE MODEL GUIDANCE HAS BEEN
SLOWLY CONVERGING ON THE TIMING OF THE CUTOFF LOW BEING EJECT ACRS
INTO THE SOUTHERN STREAM AROUND FRIDAY. HOWEVER...THERE IS STILL
SOME DISAGREEMENT ON THAT...WITH THE GFS CONSISTENTLY
FASTER/EARLIER...AND THE ECMWF SLOWER/DEEPER. THE LATEST WPC
PREFERENCE IS WITH THE ENSEMBLE MEAN...SLOWER THAN THE GFS...AND NOT
AS DEEP WITH THE RESULTED PROGRESSIVE SHORTWAVE TROF AS THE ECMWF.
AT THE SFC...A BROAD AREA OF CANADIAN HIGH PRES WILL ENCOMPASS ABOUT
3/4TH OF THE CONUS ON WEDNESDAY...GRADUALLY MODIFYING AND DRIFTING
EAST WITH THE CENTER CROSSING THE CWFA EARLY FRIDAY. DRY WEATHER AND
SLIGHTLY BELOW NORMAL TEMPS ARE EXPECTED WEDNESDAY THRU THURSDAY
NIGHT. AS THE EJECTING UPPER TROF FINALLY ENTERS THE SOUTHERN
PLAINS...A LOW PRES SYSTEM SHUD BEGIN TO ORGANIZE...TAPPING INTO
COPIOUS GULF MOISTURE. POPS WILL THEN RAMP UP BY NEXT WEEKEND. OF
COURSE...EXACT TIMING IS STILL THE MAIN QUESTION. THE 12Z GFS AND
ECMWF BOTH SHOW POSSIBLE WINTRY MIX PRECIP TYPE CONCERNS AT ONSET
FRIDAY MORNING...BUT THEN TURNING OVER TO ALL RAIN...AS STRONG SWLY
WAA SHUD DOMINATE ANY LINGERING IN SITU COLD AIR DAMMING.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
AT KCLT AND ELSEWHERE...VFR CONDITIONS WILL CONTINUE AT LEAST THRU
TONIGHT. CONSIDERABLE CLOUDINESS WILL SPREAD IN FROM THE WEST THIS
AFTERNOON THROUGH TONIGHT AS MOIST SWLY FLOW ALOFT DEVELOPS. AS
DEEPER GULF MOISTURE ASSOCIATED WITH A WAVE OF LOW APPROACHES FROM
THE SW...MVFR CLOUDS WITH PRECIP WILL SPREAD ACROSS THE AREA FROM
WEST TO EAST LATE TONIGHT THRU EARLY SUN MORNING. LATEST GUIDANCE IS
SUPPORTIVE OF IFR VSBY/CIGS WITH ONGOING SHRA THRU 18Z SUN...AS A
WAVE OF LOW PASSES JUST TO OUR NORTH. THERE APPEARS TO BE A CHANCE
OF THUNDER AS MODEL SOUNDINGS DEPICT WEAK ELEVATED INSTABILITY ON
SUN AFTERNOON. DUE TO THE UNCERTAINTY...THUNDER WAS NOT CARRIED IN
THE TAF. LIGHT SW WINDS SHOULD PREVAIL THRU THE PERIOD...EXCEPT KAVL
WHERE S WINDS WILL VEER TO THE NORTH BY SUN AFTERNOON.
OUTLOOK...PERIODS OF RAIN AND FLIGHT RESTRICTIONS ARE EXPECTED
THROUGHOUT SUNDAY...MONDAY...AND MONDAY NIGHT BEFORE GRADUAL
IMPROVEMENT OCCURS THROUGHOUT TUESDAY. DRY HIGH PRESSURE SHOULD
RETURN BY MID-WEEK.
CONFIDENCE TABLE...
22-04Z 04-10Z 10-16Z 16-18Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% MED 66% HIGH 91%
KAVL HIGH 100% HIGH 100% MED 66% HIGH 87%
KHKY HIGH 100% HIGH 100% HIGH 87% HIGH 93%
KGMU HIGH 100% HIGH 100% MED 66% HIGH 100%
KAND HIGH 100% HIGH 100% MED 66% HIGH 87%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY
EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS
ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...DEO
NEAR TERM...NED
SHORT TERM...PM
LONG TERM...ARK
AVIATION...JOH
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
306 PM EST SAT DEC 27 2014
.SYNOPSIS...
A SERIES OF SMALL LOW PRESSURE WILL MOVE NORTHEAST ALONG A COLD
FRONT AS THE FRONT SLOWLY CROSSES OUR REGION FROM THE WEST THROUGH
MONDAY. COOLER HIGH PRESSURE WILL BUILD OVER OUR REGION IN THE MID
TO LATTER PART OF THE WEEK. ANOTHER LOW PRESSURE WILL GET ORGANIZED
OVER TEXAS AND REACH OUR AREA NEXT WEEKEND.
&&
.NEAR TERM /THROUGH SUNDAY/...
AS OF 240 PM EST SATURDAY...THE LATEST SATELLITE IMAGE SHOWS A DEEP
AND MOIST WARM CONVEYOR BELT EXTENDING FROM THE GREAT LAKES REGION
DOWN TO THE WESTERN GULF...AND TO THE EASTERN PACIFIC...WITH BROAD
AREAS OF CONVECTION DEVELOPING ACROSS THE DEEP SOUTH AS OF THIS
AFTERNOON HOURS. AS AN EASTERN CONUS UPPER RIDGE AXIS PUSHES OFF THE
ATLANTIC COAST AND MOIST SWLY FLOW ALOFT SETS UP OVER THE SOUTHEAST
US...MID TO LOW LEVEL CLOUDS WILL SPREAD OVER THE PIEDMONT THROUGH
THE AFTERNOON HOURS.THE LATEST SHORT TERM MODELS CONTINUE TO
INDICATE THAT A COLD FRONT WILL SLOWLY MOVE EAST ACROSS THE
MISSISSIPPI VALLEY AND INTO THE TN VALLEY TONIGHT INTO SUN
MORNING...REACHING THE SOUTHERN APPALACHIANS BY SUN AFTERNOON. AHEAD
OF THIS FRONT...A DEEP PLUME OF GULF MOISTURE WILL BE DRAWN UP INTO
THE REGION AS A WAVE OF LOW OVER THE WESTERN GULF LIFTS NE ACROSS
AL/MI TONIGHT. THEREFORE...POPS QUICKLY RAMP UP FROM WEST TO EAST
INTO THE CATEGORICAL RANGE OVER THE WESTERN MTNS ZONES AND NE
GA...WITH LIKELY RANGE OVER THE REST OF THE WESTERN HALF OF THE CWA.
THE BEST RAINFALL RATES WILL OCCUR BETWEEN 12Z-18Z SUN WHEN THE
SURFACE WAVE OF LOW LIFTS NE ACROSS THE CWA AND A SERIES OF UPPER
DISTURBANCES RIPPLES ACROSS THE MTNS ZONES IN SWLY FLOW ALOFT.
ALSO...HAVE MENTIONED A CHANCE OF THUNDER ACROSS MUCH OF THE REGION
EARLY SUN AFTERNOON DUE TO THE PRESENCE OF 100-200J/KG MUCAPE PER
LATEST NAM/GFS/ECMWF. POPS RAMP DOWN TO THE LIKELY RANGE OVER THE
MTN ZONES AND SOLD CHANCE RANGE OVER THE SOUTHERN TIER OF THE REGION
18Z THRU 00Z MON AS THE UPPER FORCING AND THE SURFACE WAVE OF LOW
MOVES OFF TO THE NE. WITH MODELS TRENDING A BIT WETTER FOR THE
UPCOMING EVENT...HAVE GONE WITH THE HPC QPF GUIDANCE RESULTING IN
0.75-1.0" OVER THE WESTERN NC MTNS AND NE GA... WITH AROUND
0.25-0.5" ELSEWEHRE THRU SUN EVENINING.
WITH CONSIDERABLE CLOUD COVER AND WAA SOUTHERLY FLOW...OVERNIGHT
TEMPS WILL STAY 7-10 DEGREES ABOVE NORMAL. WITH ONGOING
PRECIP...AFTERNOON HIGHS ON SUN WILL BE AROUND 3-5 DEGREES COOLER
THAN TODAY.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
AS OF 200 PM SATURDAY...THE MODELS SUGGEST THAT WE WILL BE IN A LULL
OF SORTS AT THE START OF THE SHORT RANGE PERIOD SUNDAY EVENING...AS
WE WILL BE IN A MINIMUM OF FORCING. THAT CHANGES QUICKLY BY LATE
EVENING AS THE RIGHT ENTRANCE REGION OF THE UPPER JET TRANSLATES
OVERHEAD BETWEEN ROUGHLY 03Z AND 09Z...AND THE MAIN SHORT WAVE AXIS
MOVES THROUGH IN THE 06Z TO 12Z MONDAY TIME FRAME. ALTHO THE WAVE
SHEARS AND DEAMPLIFIES AS IT CROSSES THE REGION...THE FORCING SHOULD
STILL BE SUFFICIENT TO INCREASE PRECIP PRODUCTION...COMBINED WITH
IMPROVED MOIST ISENTROPIC LIFT. SO...PRECIP CHANCES RAMP BACK UP TO
CATEGORICAL MAINLY OVER THE AREA ALONG AND N/W OF I-85...AND LIKELY
TO THE S...BY 06Z OR SO. THE MAIN FORCING SHOULD SHIFT E OF THE AREA
MONDAY MORNING. THE HIGHEST PRECIP PROBABILITY WILL BE OVER THE WRN
NC PIEDMONT ON MONDAY MORNING. POP WAS LIMITED TO LIKELY OUT OF
UNCERTAINTY WITH TIMING THE DEPARTURE OF THE FORCING...BUT COULD
EASILY HAVE TO BE KEPT CATEGORICAL BEYOND 12Z MONDAY WITH THE
SLIGHTEST DELAY. THE REST OF MONDAY WILL HAVE A SLOW RAMP DOWN
THROUGH THE CHANCE RANGE AS FORCING GRADUALLY WEAKENS BEHIND THE
SURFACE FRONT THAT CROSSES FIRST THING IN THE DAY. FOR MONDAY NIGHT
AND TUESDAY...THERE IS UNCERTAINTY REGARDING THE EXTENT/CHANCE OF
PRECIP. THE LOW LEVEL FLOW COMES AROUND TO SOMETHING NW MONDAY NIGHT
AND TUESDAY WHICH SHOULD FORCE SOME SHOWER ACTIVITY NEAR THE TN
BORDER. THE PASSAGE OF ANOTHER SHORT WAVE COMBINED WITH SOME LOW
LEVEL FRONTOGENESIS APPEARS TO BE RESPONSIBLE FOR THE REDEVELOPMENT
OF PRECIP ON TUESDAY OFF TO OUR N...WHICH SOME OF THE GUIDANCE
BLEEDS DOWN INTO NC. PREFER TO KEEP THE BETTER CHANCES IN THE
UPSLOPE AREAS OF THE NRN MTNS AND TO KEEP THE AREA E OF THE BLUE
RIDGE DRY FOR THE TIME BEING. TEMPS SHOULD DROP BACK DOWN TO NEAR
NORMAL ON TUESDAY.
ON SUNDAY THE FAIRLY BROAD FRONTAL ZONE WILL
EXTEND FROM QUEBEC SWWD TO THE WRN GULF COAST...BISECTING THE TENN
VALLEY JUST TO OUR WEST. AT LEAST ONE WEAK WAVE IS PROGGED TO RIDE
UP THE FRONT DURING THE DAY AS A RESULT OF CYCLONIC UPPER FLOW OVER
THE BOUNDARY CONTAINING EMBEDDED WEAK VORTICES. THOUGH SUCH A WAVE
WOULD LIKELY PROVIDE LOCAL ENHANCEMENT TO LLVL WARM/MOIST ADVECTION
AHEAD OF THE FRONT...THE EXISTENCE OF ONE IS IN QUESTION GIVEN THE
POOR AGREEMENT AND CONSISTENCY FROM GUIDANCE ON HOW THIS OCCURS.
OVERALL THE FORCING SUNDAY IS JUST NOT ALL THAT IMPRESSIVE. LITTLE
TO NO INSTABILITY IS PROGGED OVER THE CWFA AND THOUGH A GOOD SLUG OF
MOISTURE TRANSPORT IS PRESENT ON NAM/GFS PROGS THE LLVL LIFT IS
LIMITED. AT ANY RATE...THRU SUNDAY THE FRONT REMAINS NEARLY
STATIONARY ACRS THE SOUTHEAST...THE PARENT LOW CONTINUING TO
PROGRESS EWD WITH THE ACTIVE NRN STREAM WHILE THE BROAD SRN STREAM
TROUGH IS HELD OFF BY THE BERMUDA HIGH. IT APPEARS THE FRONT WILL
NOT ACTUALLY ENTER THE AREA UNTIL MONDAY MRNG...WITH A DISTINCT
500MB SHORTWAVE ACCOMPANYING IT AS WELL AS UPPER DIVERGENCE ASSOC
WITH RR QUAD OF A JET STREAK.
TWO PEAKS OF PRECIP ACTIVITY ARE SUGGESTED WHEN THE TOTAL FORCING IS
MAXIMIZED...SUNDAY MRNG AND THEN EARLY MON MRNG. HOWEVER IT IS
DIFFICULT TO PICK OUT A POINT BETWEEN WHERE A LULL SHOULD BE
BETWEEN...WITH THE OVERALL PATTERN REMAINING FAVORABLE FOR AT LEAST
LIGHT PRECIP. WILL CONTINUE TO ADVERTISE LIKELY POPS MOST OF THE AREA
THROUGHOUT SUNDAY...BUT CONCENTRATING MORE QPF CLOSE TO THE
AFOREMENTIONED PEAKS. DESPITE CLOUDS AND RAIN...IN THE WARM AIRMASS
TEMPS SHOULD TOP OUT 5-9 DEGREES ABOVE NORMAL SUN AFTN...WITH MINS
MON MRNG BEING EVEN MORE ABOVE NORMAL...UPPER 40S AND LOWER 50S. MAX
TEMPS MONDAY WILL BE SLIGHTLY WARMER THAN SUNDAY OVER THE PIEDMONT
WITH THE FRONT NOT YET HAVING AN IMPACT.
PROGRESSION OF THE UPPER PATTERN IS STILL PRETTY SLOW THRU MON
NIGHT...WITH THE CWFA NEAR THE INFLECTION POINT BETWEEN THE PLAINS
TROUGH AND THE ATLANTIC RIDGE. POPS DECLINE ONLY GRADUALLY THRU THE
END OF THE PERIOD WITH MOST OF THE GUIDANCE INDICATING SOME QPF
CONTINUING ON THE BACK SIDE OF ANOTHER FRONTAL WAVE DEVELOPING NEAR
THE GA/SC COAST. COLDER AIR WILL BEGIN TO RETURN TO ALL AREAS ON THE
ENSUING NLY FLOW MON NIGHT...THOUGH MIN TEMPS WILL STILL BE AROUND 10
DEGREES ABOVE CLIMO.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
AS OF 215 PM SATURDAY...THE MEDIUM RANGE WILL START OUT WITH SPLIT
UPPER LVL FLOW...WITH A LARGE POLAR VORTEX SPINNING OVR HUDSON
BAY...AND A CUTOFF LOW INVOF CALIFORNIA. THE MODEL GUIDANCE HAS BEEN
SLOWLY CONVERGING ON THE TIMING OF THE CUTOFF LOW BEING EJECT ACRS
INTO THE SOUTHERN STREAM AROUND FRIDAY. HOWEVER...THERE IS STILL
SOME DISAGREEMENT ON THAT...WITH THE GFS CONSISTENTLY
FASTER/EARLIER...AND THE ECMWF SLOWER/DEEPER. THE LATEST WPC
PREFERENCE IS WITH THE ENSEMBLE MEAN...SLOWER THAN THE GFS...AND NOT
AS DEEP WITH THE RESULTED PROGRESSIVE SHORTWAVE TROF AS THE ECMWF.
AT THE SFC...A BROAD AREA OF CANADIAN HIGH PRES WILL ENCOMPASS ABOUT
3/4TH OF THE CONUS ON WEDNESDAY...GRADUALLY MODIFYING AND DRIFTING
EAST WITH THE CENTER CROSSING THE CWFA EARLY FRIDAY. DRY WEATHER AND
SLIGHTLY BELOW NORMAL TEMPS ARE EXPECTED WEDNESDAY THRU THURSDAY
NIGHT. AS THE EJECTING UPPER TROF FINALLY ENTERS THE SOUTHERN
PLAINS...A LOW PRES SYSTEM SHUD BEGIN TO ORGANIZE...TAPPING INTO
COPIOUS GULF MOISTURE. POPS WILL THEN RAMP UP BY NEXT WEEKEND. OF
COURSE...EXACT TIMING IS STILL THE MAIN QUESTION. THE 12Z GFS AND
ECMWF BOTH SHOW POSSIBLE WINTRY MIX PRECIP TYPE CONCERNS AT ONSET
FRIDAY MORNING...BUT THEN TURNING OVER TO ALL RAIN...AS STRONG SWLY
WAA SHUD DOMINATE ANY LINGERING IN SITU COLD AIR DAMMING.
&&
.AVIATION /20Z SATURDAY THROUGH THURSDAY/...
AT KCLT AND ELSEWHERE...VFR CONDITIONS WILL CONTINUE AT LEAST THRU
TONIGHT. CONSIDERABLE CLOUDINESS WILL SPREAD IN FROM THE WEST THIS
AFTERNOON THROUGH TONIGHT AS MOIST SWLY FLOW ALOFT DEVELOPS. AS
DEEPER GULF MOISTURE ASSOCIATED WITH A WAVE OF LOW APPROACHES FROM
THE SW...MVFR CLOUDS WITH PRECIP WILL SPREAD ACROSS THE AREA FROM
WEST TO EAST LATE TONIGHT THRU EARLY SUN MORNING. LATEST GUIDANCE IS
SUPPORTIVE OF IFR VSBY/CIGS WITH ONGOING SHRA THRU 18Z SUN...AS A
WAVE OF LOW PASSES JUST TO OUR NORTH. THERE APPEARS TO BE A CHANCE
OF THUNDER AS MODEL SOUNDINGS DEPICT WEAK ELEVATED INSTABILITY ON
SUN AFTERNOON. DUE TO THE UNCERTAINTY...THUNDER WAS NOT CARRIED IN
THE TAF. LIGHT SW WINDS SHOULD PREVAIL THRU THE PERIOD...EXCEPT KAVL
WHERE S WINDS WILL VEER TO THE NORTH BY SUN AFTERNOON.
OUTLOOK...PERIODS OF RAIN AND FLIGHT RESTRICTIONS ARE EXPECTED
THROUGHOUT SUNDAY...MONDAY...AND MONDAY NIGHT BEFORE GRADUAL
IMPROVEMENT OCCURS THROUGHOUT TUESDAY. DRY HIGH PRESSURE SHOULD
RETURN BY MID-WEEK.
CONFIDENCE TABLE...
20-02Z 02-08Z 08-14Z 14-18Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 95%
KGSP HIGH 100% HIGH 100% MED 77% HIGH 83%
KAVL HIGH 100% HIGH 100% MED 64% MED 77%
KHKY HIGH 100% HIGH 100% HIGH 93% HIGH 82%
KGMU HIGH 100% HIGH 100% MED 74% HIGH 85%
KAND HIGH 100% HIGH 100% MED 72% HIGH 80%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY
EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS
ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...DEO
NEAR TERM...JOH
SHORT TERM...PM
LONG TERM...ARK
AVIATION...JOH
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1246 PM EST SAT DEC 27 2014
.SYNOPSIS...
A SERIES OF SMALL LOW PRESSURE WILL MOVE NORTHEAST ALONG A COLD
FRONT AS THE FRONT SLOWLY CROSSES OUR REGION FROM THE WEST THROUGH
MONDAY. COOLER HIGH PRESSURE WILL BUILD OVER OUR REGION IN THE MID
TO LATTER PART OF THE WEEK. ANOTHER LOW PRESSURE WILL GET ORGANIZED
OVER TEXAS AND REACH OUR AREA NEXT WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
1145 AM EST UPDATE...LATEST RADAR TREND SHOWS AREAS OF LIGHT PRECIP
CURRENTLY OVER THE NORTH-CENTRAL GA LIFTING NORTHEAST TOWARDS NE GA
AND SW MTNS ZONES AS OF LATE MORNING HOURS. LATEST MESO-SCALE MODELS
INCLUDING THE RAP AND HRRR SUGGEST THAT THE AFOREMENTIONED FEATURE
WILL REACH THE NE GA AND SW MTN ZONES BY AROUND 18Z AND DRIES OUT
TOWARD 21Z. HENCE...HAVE KEPT THE LOW-END CHANCE POPS OVER THE
EXTREME WESTERN TIER OF THE CWA...BEFORE RAMPING DOWN TO THE SLIGHT
CHANCE RANGE BY 21Z. POPS THEN RAMP UP FROM WEST TO EAST THROUGH
TONIGHT AS DEEPER GULF MOISTURE ARRIVES. AS FOR THE PRECIP
TYPE...HAVE MENTIONED SHOWERS THROUGH SUNDAY... WITH CHANCE OF
THUNDER...OVER THE WESTERN PORTIONS OF THE CWA AS MODELS SUGGEST
THAT SOME DEGREE OF ELEVATED INSTABILITY (100-200J/KG MUCAPE)WILL BE
PRESENT ON SUN AFTERNOON. HAVE RAISED THE QPF THRU SUN AFTERNOON PER
LATEST GUIDANCE.
845AM EST UPDATE...THE LATEST REGIONAL RADARS SHOW AREAS OF LIGHT
RETURNS OVER PORTIONS OF NE GA AND THE EXTREME WESTERN NC MTNS AS OF
THIS MORNING...IN LIGHT OF A WEAK UPPER DISTURBANCE LIFTING NE
ACROSS THE WESTERN ZONES OF THE CWA. ALSO...AREAS OF LIGHT PRECIP
CURRENTLY OVER AL AND PORTIONS OF NW GA WILL MOVE
EASTWARD...REACHING NE GA AND SW MTNS BY AROUND 18Z TODAY.
HOWEVER...LATEST HRRR SUGGESTS THIS FEATURE WILL WEAKEN AS IT ENTERS
OUR CWA ATT. HENCE...SLIGHT CHANCE TO THE LOW END CHANCE POPS WERE
WARRANTED THERE THROUGH THE MORNING HOURS INTO EARLY PART OF THIS
AFTERNOON. WITH TEMPS WARMING UP ABOVE THE FREEZING LEVEL...SHRA WAS
MENTIONED IN THE WX GRID.
AS OF 630 AM...LIGHT RETURNS ON REGIONAL 88DS ARE BEGINNING TO LIFT
NE OF THE AREA. THERE WAS ACTUALLY A LITTLE LIGHT SLEET REPORTED
UNDERNEATH SOME OF THIS ACTIVITY ACROSS THE MTNS EARLIER...WHICH IS
SURPRISING CONSIDERING THE VERY DRY SUBCLOUD LAYER (WITH CLOUDS
BASES AT AROUND 10 KFT). WITH RADAR EHCOES DIMINISHING...WILL
CONTINUE TO FEATURE A PRECIPITATION-LESS FORECAST THIS MORNING.
TEMPS SHOULD WARM TO AROUND 50 ACROSS THE PIEDMONT/FHILLS AND MTN
VALLEYS BY LATE MORNING.
A LOW AMPLITUDE RIDGE WILL PERSIST ALONG THE EAST COAST TODAY...
BEFORE MOVING OFF THE COAST BY THE END OF THE PERIOD...AS AN
UPSTREAM TROUGH BEGINS TO EJECT FROM TEXAS/THE SOUTHERN PLAINS.
TODAY WILL SEE A VARYING DEGREE OF MID/HIGH LEVEL CLOUD COVER ACROSS
THE WESTERN CAROLINAS AND NORTHEAST GEORGIA...RESULTING IN PARTLY
CLOUDY SKIES ACROSS MUCH OF THE AREA. MAX TEMPS WILL AVERAGE AROUND
10 DEGREES ABOVE CLIMO.
RAIN CHANCES INCREASE TONIGHT...AS A WEAK FRONTAL ZONE AND
ASSOCIATED WEAK LOW PRESSURE MOVE ACROSS THE TENN VALLEY. RESULTANT
ISENTROPIC LIFT/LOW LEVEL CONVERGENCE AND WEAK MID-LEVEL SHORT WAVE
TROUGH SHOULD SUPPORT RAIN MOVING INTO THE WESTERN ZONES BY MIDNIGHT
OR SO. RAIN CHANCES DIMINISH TOWARD THE SOUTHEAST...AS THE BEST
FORCING IS EXPECTED TO LIFT NORTHEAST ACROSS THE CWA BETWEEN 06 AND
12Z. POPS WILL RANGE FROM CATEGORICAL ACROSS THE MOUNTAINS/NC
FOOTHILLS/NORTHWEST UPSTATE...TO THE LOW END OF LIKELY ACROSS THE
SOUTHEAST ZONES. RAINFALL AMOUNTS THROUGH 12Z SHOULD RANGE FROM A
QUARTER TO HALF INCH ACROSS THE MOUNTAINS AND ADJACENT FOOTHILLS...
TO LESS THAN A QUARTER INCH ACROSS MUCH OF THE PIEDMONT. MIN TEMPS
WILL BE WELL ABOVE NORMAL.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 300 AM SAT...ON SUNDAY THE FAIRLY BROAD FRONTAL ZONE WILL
EXTEND FROM QUEBEC SWWD TO THE WRN GULF COAST...BISECTING THE TENN
VALLEY JUST TO OUR WEST. AT LEAST ONE WEAK WAVE IS PROGGED TO RIDE UP
THE FRONT DURING THE DAY AS A RESULT OF CYCLONIC UPPER FLOW OVER THE
BOUNDARY CONTAINING EMBEDDED WEAK VORTICES. THOUGH SUCH A WAVE WOULD
LIKELY PROVIDE LOCAL ENHANCEMENT TO LLVL WARM/MOIST ADVECTION AHEAD
OF THE FRONT...THE EXISTENCE OF ONE IS IN QUESTION GIVEN THE POOR
AGREEMENT AND CONSISTENCY FROM GUIDANCE ON HOW THIS OCCURS. OVERALL
THE FORCING SUNDAY IS JUST NOT ALL THAT IMPRESSIVE. LITTLE TO NO
INSTABILITY IS PROGGED OVER THE CWFA AND THOUGH A GOOD SLUG OF
MOISTURE TRANSPORT IS PRESENT ON NAM/GFS PROGS THE LLVL LIFT IS
LIMITED. AT ANY RATE...THRU SUNDAY THE FRONT REMAINS NEARLY
STATIONARY ACRS THE SOUTHEAST...THE PARENT LOW CONTINUING TO PROGRESS
EWD WITH THE ACTIVE NRN STREAM WHILE THE BROAD SRN STREAM TROUGH IS
HELD OFF BY THE BERMUDA HIGH. IT APPEARS THE FRONT WILL NOT ACTUALLY
ENTER THE AREA UNTIL MONDAY MRNG...WITH A DISTINCT 500MB SHORTWAVE
ACCOMPANYING IT AS WELL AS UPPER DIVERGENCE ASSOC WITH RR QUAD OF A
JET STREAK.
TWO PEAKS OF PRECIP ACTIVITY ARE SUGGESTED WHEN THE TOTAL FORCING IS
MAXIMIZED...SUNDAY MRNG AND THEN EARLY MON MRNG. HOWEVER IT IS
DIFFICULT TO PICK OUT A POINT BETWEEN WHERE A LULL SHOULD BE
BETWEEN...WITH THE OVERALL PATTERN REMAINING FAVORABLE FOR AT LEAST
LIGHT PRECIP. WILL CONTINUE TO ADVERTISE LIKELY POPS MOST OF THE AREA
THROUGHOUT SUNDAY...BUT CONCENTRATING MORE QPF CLOSE TO THE
AFOREMENTIONED PEAKS. DESPITE CLOUDS AND RAIN...IN THE WARM AIRMASS
TEMPS SHOULD TOP OUT 5-9 DEGREES ABOVE NORMAL SUN AFTN...WITH MINS
MON MRNG BEING EVEN MORE ABOVE NORMAL...UPPER 40S AND LOWER 50S. MAX
TEMPS MONDAY WILL BE SLIGHTLY WARMER THAN SUNDAY OVER THE PIEDMONT
WITH THE FRONT NOT YET HAVING AN IMPACT.
PROGRESSION OF THE UPPER PATTERN IS STILL PRETTY SLOW THRU MON
NIGHT...WITH THE CWFA NEAR THE INFLECTION POINT BETWEEN THE PLAINS
TROUGH AND THE ATLANTIC RIDGE. POPS DECLINE ONLY GRADUALLY THRU THE
END OF THE PERIOD WITH MOST OF THE GUIDANCE INDICATING SOME QPF
CONTINUING ON THE BACK SIDE OF ANOTHER FRONTAL WAVE DEVELOPING NEAR
THE GA/SC COAST. COLDER AIR WILL BEGIN TO RETURN TO ALL AREAS ON THE
ENSUING NLY FLOW MON NIGHT...THOUGH MIN TEMPS WILL STILL BE AROUND 10
DEGREES ABOVE CLIMO.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 200 AM SAT...QUASI-ZONAL UPPER FLOW CONTINUES OVER THE SUN BELT
TUESDAY EVEN AS A POLAR TROUGH MOVES INTO THE CONUS AND SHEARS INTO
TWO SHORTWAVES TO OUR NORTH AND WEST. ONE WAVE MOVES OVER THE GREAT
LAKES AND CONTRIBUTES TO GENTLE HEIGHT FALLS OVER THE SOUTHEAST
MID-WEEK...WHILE THE OTHER CUTS OFF OVER THE SOUTHWEST AND LEADS TO
THE DEVELOPMENT OF A SFC LOW OVER THE SRN PLAINS OR ARKLATEX BY THE
END OF THE WEEK. CONFLUENCE DOWNSTREAM OF THE SW TROUGH WILL PRODUCE
A SPRAWLING SFC HIGH WHICH WILL SPREAD ACRS THE OH VALLEY AND SRN
STATES TUE NIGHT THRU FRI. THIS WILL BRING SEASONABLY COOL CONDITIONS
FOR OUR AREA WITH TEMPS A SHADE BELOW CLIMO. MOST OF THE PERIOD LOOKS
DRY BEFORE POPS START RAMPING UP THU NIGHT AHEAD OF THE DEVELOPING
LOW.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
AT KCLT AND ELSEWHERE...VFR CONDITIONS WILL CONTINUE AT LEAST THRU
TONIGHT. CONSIDERABLE CLOUDINESS WILL SPREAD IN FROM THE WEST THIS
AFTERNOON THRU THRU TONIGHT AS MOIST SWLY FLOW ALOFT DEVELOPS. AS
DEEPER GULF MOISTURE ASSOCIATED WITH A WAVE OF LOW APPROACHES FROM
THE SW...MVFR CLOUDS WITH PRECIP WILL SPREAD ACROSS THE AREA FROM
WEST TO EAST LATE TONIGHT THRU EARLY SUN MORNING. LATEST GUIDANCE IS
SUPPORTIVE OF IFR VSBY/CIGS WITH ONGOING SHRA THRU 18Z SUN...AS A
WAVE OF LOW PASSES JUST TO OUR NORTH. LIGHT SW WINDS SHOULD PREVAIL
THRU THE PERIOD...EXECPT KAVL WHERE S WINDS WILL VEER TO THE NORTH
BY SUN AFTERNOON.
OUTLOOK...PERIODS OF RAIN AND FLIGHT RESTRICTIONS ARE EXPECTED
THROUGHOUT SUNDAY...MONDAY...AND MONDAY NIGHT BEFORE GRADUAL
IMPROVEMENT OCCURS THROUGHOUT TUESDAY. DRY HIGH PRESSURE SHOULD
RETURN BY MID-WEEK.
CONFIDENCE TABLE...
17-23Z 23-05Z 05-11Z 11-12Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% LOW 53%
KAVL HIGH 100% HIGH 100% HIGH 100% MED 70%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 80%
KGMU HIGH 100% HIGH 100% HIGH 100% MED 70%
KAND HIGH 100% HIGH 100% HIGH 100% MED 70%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY
EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS
ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...DEO
NEAR TERM...JDL/JOH
SHORT TERM...WIMBERLEY
LONG TERM...ARK/WIMBERLEY
AVIATION...JOH
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1208 PM EST SAT DEC 27 2014
.SYNOPSIS...
A SERIES OF SMALL LOW PRESSURE WILL MOVE NORTHEAST ALONG A COLD
FRONT AS THE FRONT SLOWLY CROSSES OUR REGION FROM THE WEST THROUGH
MONDAY. COOLER HIGH PRESSURE WILL BUILD OVER OUR REGION IN THE MID
TO LATTER PART OF THE WEEK. ANOTHER LOW PRESSURE WILL GET ORGANIZED
OVER TEXAS AND REACH OUR AREA NEXT WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
1145 AM EST UPDATE...LATEST RADAR TREND SHOWS AREAS OF LIGHT PRECIP
CURRENTLY OVER THE NORTH-CENTRAL GA LIFTING NORTHEAST TOWARDS NE GA
AND SW MTNS ZONES AS OF LATE MORNING HOURS. LATEST MESO-SCALE MODELS
INCLUDING THE RAP AND HRRR SUGGEST THAT THE AFOREMENTIONED FEATURE
WILL REACH THE NE GA AND SW MTN ZONES BY AROUND 18Z AND DRIES OUT
TOWARD 21Z. HENCE...HAVE KEPT THE LOW-END CHANCE POPS OVER THE
EXTREME WESTERN TIER OF THE CWA...BEFORE RAMPING DOWN TO THE SLIGHT
CHANCE RANGE BY 21Z. POPS THEN RAMP UP FROM WEST TO EAST THROUGH
TONIGHT AS DEEPER GULF MOISTURE ARRIVES. AS FOR THE PRECIP
TYPE...HAVE MENTIONED SHOWERS THROUGH SUNDAY... WITH CHANCE OF
THUNDER...OVER THE WESTERN PORTIONS OF THE CWA AS MODELS SUGGEST
THAT SOME DEGREE OF ELEVATED INSTABILITY (100-200J/KG MUCAPE)WILL BE
PRESENT ON SUN AFTERNOON. HAVE RAISED THE QPF THRU SUN AFTERNOON PER
LATEST GUIDANCE.
845AM EST UPDATE...THE LATEST REGIONAL RADARS SHOW AREAS OF LIGHT
RETURNS OVER PORTIONS OF NE GA AND THE EXTREME WESTERN NC MTNS AS OF
THIS MORNING...IN LIGHT OF A WEAK UPPER DISTURBANCE LIFTING NE
ACROSS THE WESTERN ZONES OF THE CWA. ALSO...AREAS OF LIGHT PRECIP
CURRENTLY OVER AL AND PORTIONS OF NW GA WILL MOVE
EASTWARD...REACHING NE GA AND SW MTNS BY AROUND 18Z TODAY.
HOWEVER...LATEST HRRR SUGGESTS THIS FEATURE WILL WEAKEN AS IT ENTERS
OUR CWA ATT. HENCE...SLIGHT CHANCE TO THE LOW END CHANCE POPS WERE
WARRANTED THERE THROUGH THE MORNING HOURS INTO EARLY PART OF THIS
AFTERNOON. WITH TEMPS WARMING UP ABOVE THE FREEZING LEVEL...SHRA WAS
MENTIONED IN THE WX GRID.
AS OF 630 AM...LIGHT RETURNS ON REGIONAL 88DS ARE BEGINNING TO LIFT
NE OF THE AREA. THERE WAS ACTUALLY A LITTLE LIGHT SLEET REPORTED
UNDERNEATH SOME OF THIS ACTIVITY ACROSS THE MTNS EARLIER...WHICH IS
SURPRISING CONSIDERING THE VERY DRY SUBCLOUD LAYER (WITH CLOUDS
BASES AT AROUND 10 KFT). WITH RADAR EHCOES DIMINISHING...WILL
CONTINUE TO FEATURE A PRECIPITATION-LESS FORECAST THIS MORNING.
TEMPS SHOULD WARM TO AROUND 50 ACROSS THE PIEDMONT/FHILLS AND MTN
VALLEYS BY LATE MORNING.
A LOW AMPLITUDE RIDGE WILL PERSIST ALONG THE EAST COAST TODAY...
BEFORE MOVING OFF THE COAST BY THE END OF THE PERIOD...AS AN
UPSTREAM TROUGH BEGINS TO EJECT FROM TEXAS/THE SOUTHERN PLAINS.
TODAY WILL SEE A VARYING DEGREE OF MID/HIGH LEVEL CLOUD COVER ACROSS
THE WESTERN CAROLINAS AND NORTHEAST GEORGIA...RESULTING IN PARTLY
CLOUDY SKIES ACROSS MUCH OF THE AREA. MAX TEMPS WILL AVERAGE AROUND
10 DEGREES ABOVE CLIMO.
RAIN CHANCES INCREASE TONIGHT...AS A WEAK FRONTAL ZONE AND
ASSOCIATED WEAK LOW PRESSURE MOVE ACROSS THE TENN VALLEY. RESULTANT
ISENTROPIC LIFT/LOW LEVEL CONVERGENCE AND WEAK MID-LEVEL SHORT WAVE
TROUGH SHOULD SUPPORT RAIN MOVING INTO THE WESTERN ZONES BY MIDNIGHT
OR SO. RAIN CHANCES DIMINISH TOWARD THE SOUTHEAST...AS THE BEST
FORCING IS EXPECTED TO LIFT NORTHEAST ACROSS THE CWA BETWEEN 06 AND
12Z. POPS WILL RANGE FROM CATEGORICAL ACROSS THE MOUNTAINS/NC
FOOTHILLS/NORTHWEST UPSTATE...TO THE LOW END OF LIKELY ACROSS THE
SOUTHEAST ZONES. RAINFALL AMOUNTS THROUGH 12Z SHOULD RANGE FROM A
QUARTER TO HALF INCH ACROSS THE MOUNTAINS AND ADJACENT FOOTHILLS...
TO LESS THAN A QUARTER INCH ACROSS MUCH OF THE PIEDMONT. MIN TEMPS
WILL BE WELL ABOVE NORMAL.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 300 AM SAT...ON SUNDAY THE FAIRLY BROAD FRONTAL ZONE WILL
EXTEND FROM QUEBEC SWWD TO THE WRN GULF COAST...BISECTING THE TENN
VALLEY JUST TO OUR WEST. AT LEAST ONE WEAK WAVE IS PROGGED TO RIDE UP
THE FRONT DURING THE DAY AS A RESULT OF CYCLONIC UPPER FLOW OVER THE
BOUNDARY CONTAINING EMBEDDED WEAK VORTICES. THOUGH SUCH A WAVE WOULD
LIKELY PROVIDE LOCAL ENHANCEMENT TO LLVL WARM/MOIST ADVECTION AHEAD
OF THE FRONT...THE EXISTENCE OF ONE IS IN QUESTION GIVEN THE POOR
AGREEMENT AND CONSISTENCY FROM GUIDANCE ON HOW THIS OCCURS. OVERALL
THE FORCING SUNDAY IS JUST NOT ALL THAT IMPRESSIVE. LITTLE TO NO
INSTABILITY IS PROGGED OVER THE CWFA AND THOUGH A GOOD SLUG OF
MOISTURE TRANSPORT IS PRESENT ON NAM/GFS PROGS THE LLVL LIFT IS
LIMITED. AT ANY RATE...THRU SUNDAY THE FRONT REMAINS NEARLY
STATIONARY ACRS THE SOUTHEAST...THE PARENT LOW CONTINUING TO PROGRESS
EWD WITH THE ACTIVE NRN STREAM WHILE THE BROAD SRN STREAM TROUGH IS
HELD OFF BY THE BERMUDA HIGH. IT APPEARS THE FRONT WILL NOT ACTUALLY
ENTER THE AREA UNTIL MONDAY MRNG...WITH A DISTINCT 500MB SHORTWAVE
ACCOMPANYING IT AS WELL AS UPPER DIVERGENCE ASSOC WITH RR QUAD OF A
JET STREAK.
TWO PEAKS OF PRECIP ACTIVITY ARE SUGGESTED WHEN THE TOTAL FORCING IS
MAXIMIZED...SUNDAY MRNG AND THEN EARLY MON MRNG. HOWEVER IT IS
DIFFICULT TO PICK OUT A POINT BETWEEN WHERE A LULL SHOULD BE
BETWEEN...WITH THE OVERALL PATTERN REMAINING FAVORABLE FOR AT LEAST
LIGHT PRECIP. WILL CONTINUE TO ADVERTISE LIKELY POPS MOST OF THE AREA
THROUGHOUT SUNDAY...BUT CONCENTRATING MORE QPF CLOSE TO THE
AFOREMENTIONED PEAKS. DESPITE CLOUDS AND RAIN...IN THE WARM AIRMASS
TEMPS SHOULD TOP OUT 5-9 DEGREES ABOVE NORMAL SUN AFTN...WITH MINS
MON MRNG BEING EVEN MORE ABOVE NORMAL...UPPER 40S AND LOWER 50S. MAX
TEMPS MONDAY WILL BE SLIGHTLY WARMER THAN SUNDAY OVER THE PIEDMONT
WITH THE FRONT NOT YET HAVING AN IMPACT.
PROGRESSION OF THE UPPER PATTERN IS STILL PRETTY SLOW THRU MON
NIGHT...WITH THE CWFA NEAR THE INFLECTION POINT BETWEEN THE PLAINS
TROUGH AND THE ATLANTIC RIDGE. POPS DECLINE ONLY GRADUALLY THRU THE
END OF THE PERIOD WITH MOST OF THE GUIDANCE INDICATING SOME QPF
CONTINUING ON THE BACK SIDE OF ANOTHER FRONTAL WAVE DEVELOPING NEAR
THE GA/SC COAST. COLDER AIR WILL BEGIN TO RETURN TO ALL AREAS ON THE
ENSUING NLY FLOW MON NIGHT...THOUGH MIN TEMPS WILL STILL BE AROUND 10
DEGREES ABOVE CLIMO.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 200 AM SAT...QUASI-ZONAL UPPER FLOW CONTINUES OVER THE SUN BELT
TUESDAY EVEN AS A POLAR TROUGH MOVES INTO THE CONUS AND SHEARS INTO
TWO SHORTWAVES TO OUR NORTH AND WEST. ONE WAVE MOVES OVER THE GREAT
LAKES AND CONTRIBUTES TO GENTLE HEIGHT FALLS OVER THE SOUTHEAST
MID-WEEK...WHILE THE OTHER CUTS OFF OVER THE SOUTHWEST AND LEADS TO
THE DEVELOPMENT OF A SFC LOW OVER THE SRN PLAINS OR ARKLATEX BY THE
END OF THE WEEK. CONFLUENCE DOWNSTREAM OF THE SW TROUGH WILL PRODUCE
A SPRAWLING SFC HIGH WHICH WILL SPREAD ACRS THE OH VALLEY AND SRN
STATES TUE NIGHT THRU FRI. THIS WILL BRING SEASONABLY COOL CONDITIONS
FOR OUR AREA WITH TEMPS A SHADE BELOW CLIMO. MOST OF THE PERIOD LOOKS
DRY BEFORE POPS START RAMPING UP THU NIGHT AHEAD OF THE DEVELOPING
LOW.
&&
.AVIATION /17Z SATURDAY THROUGH WEDNESDAY/...
AT KCLT AND ELSEWHERE...HIGH/MID LEVEL CLOUDS OF VARYING DEGREES OF
THICKNESS AND COVERAGE WILL PASS OVER THE REGION THROUGHOUT THE
DAY...WITH CLOUD HEIGHTS EXPECTED TO BE AROUND 10 KFT OR HIGHER.
CIGS WILL DEVELOP/LOWER THIS EVENING...AS A COLD FRONT AND
ASSOCIATED WEAK LOW PRESSURE APPROACH FROM THE WEST. THIS IS
EXPECTED TO BRING -RA AND MVFR CIGS TO MOST OF THE TAF SITES BY THE
END OF THE PERIOD. WINDS WILL BE LIGHT THROUGH THE PERIOD...
GENERALLY FAVORING A SW DIRECTION THIS AFTERNOON/EVENING.
OUTLOOK...PERIODS OF RAIN AND FLIGHT RESTRICTIONS ARE EXPECTED
THROUGHOUT SUNDAY...MONDAY...AND MONDAY NIGHT BEFORE GRADUAL
IMPROVEMENT OCCURS THROUGHOUT TUESDAY. DRY HIGH PRESSURE SHOULD
RETURN BY MID-WEEK.
CONFIDENCE TABLE...
17-23Z 23-05Z 05-11Z 11-12Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% LOW 53%
KAVL HIGH 100% HIGH 100% HIGH 100% MED 70%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 80%
KGMU HIGH 100% HIGH 100% HIGH 100% MED 70%
KAND HIGH 100% HIGH 100% HIGH 100% MED 70%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY
EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS
ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...DEO
NEAR TERM...JDL/JOH
SHORT TERM...WIMBERLEY
LONG TERM...ARK/WIMBERLEY
AVIATION...JDL
AREA FORECAST DISCUSSION
NWS MIDLAND/ODESSA TX
400 PM CST Sat Dec 27 2014
.DISCUSSION...
Current observations continue to show intermittent light snow
continuing over portions of southeast New Mexico and the western
Permian Basin. Significant snows have ended over the Guadalupe
Mountains and across Lea County New Mexico. The HRRR and other
models suggest that lingering precipitation over these northern
areas will continue to wane while redevelopment will occur over the
higher elevations of SW Texas beginning later this afternoon into evening.
While indications are that the positive tilt upper trough is
weakening/filling as it moves across the area, which is a negative
against significant snow, current QFP for this evening and BUFKIT
sounding interrogation suggests that snow redevelopment is
likely...especially over the higher elevations of SW Texas. The
Marfa Plateau and the Davis Mountains could see significant snowfall
tonight. The western half of Pecos county could also see some minor
snow accumulations. For now, will issue a winter storm warning for
heavy snow for higher elevations of Presidio, Jeff Davis, and
Brewster County. A winter weather advisory will be issued for Pecos
County. Both the warning and advisory will be extended into the
overnight period. However, most of the activity will probably occur
this evening.
As this upper trough rapidly exits the area tomorrow morning, zonal
upper flow is expected. Surface lee trough development just east of
the Rockies will result in a quick warmup for our area tomorrow and
Monday. However, a significant cool down is forecast for later
Monday into Tuesday. The big question for now is what type of
precipitation will fall next week. With shallow cold air in place
and an expected elevated warm later, indications are that freezing
drizzle will the predominant precipitation type most of next week.
&&
.PRELIMINARY POINT TEMPS/POPS...
ANDREWS TX 26 48 29 56 / 20 0 0 0
BIG SPRING TX 28 51 33 59 / 20 0 0 0
CARLSBAD NM 22 50 30 56 / 10 0 0 0
DRYDEN TX 34 53 33 62 / 60 0 0 0
FORT STOCKTON TX 28 53 37 63 / 60 0 0 0
GUADALUPE PASS TX 22 41 30 51 / 10 0 0 0
HOBBS NM 22 46 26 54 / 10 0 0 0
MARFA TX 20 48 19 60 / 70 10 0 0
MIDLAND INTL AIRPORT TX 25 50 30 57 / 20 0 0 0
ODESSA TX 26 50 33 57 / 20 0 0 0
WINK TX 26 53 27 63 / 30 0 0 0
&&
.MAF WATCHES/WARNINGS/ADVISORIES...
NM...NONE.
TX...WINTER WEATHER ADVISORY until 3 AM CST Sunday FOR THE FOLLOWING
ZONES... Pecos.
WINTER STORM WARNING until 3 AM CST Sunday FOR THE FOLLOWING
ZONES... Big Bend Area...Davis/Apache Mountains Area...
Marfa Plateau.
&&
$$
84/03
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AREA FORECAST DISCUSSION
NWS FORT WORTH TX
254 PM CST SAT DEC 27 2014
.DISCUSSION...
THE SHORTWAVE DISTURBANCE THAT CREATED SOME WINTER PRECIPITATION
ACROSS OUR FAR NORTHWEST COUNTIES THIS PAST MORNING IS SLOWLY
EXITING THE AREA...THOUGH A FEW SLEET PELLETS REMAIN POSSIBLE WITH
ANY LINGERING LIGHT RAIN. THE SURFACE COLD FRONT IS NOW APPROACHING
THE TEXAS COAST WITH CLOUDY...WINDY AND COLD CONDITIONS ACROSS
NORTH AND CENTRAL TEXAS. SCATTERED AREAS OF LIGHT RAIN WILL LINGER
ACROSS THE FAR EAST AND SOUTHEAST COUNTIES TONIGHT INTO SUNDAY...AS
THE LARGER SCALE UPPER TROUGH MOVES EAST ACROSS THE AREA ON ON
SUNDAY. AREAS FURTHER NORTH AND WEST WILL CONTINUE TO SEE DRIER
POLAR AIR INTRUDING IN WITH JUST BRISK AND COLD CONDITIONS CONTINUING
THIS PERIOD. WE DID LOWER HIGH TEMPERATURES ON SUNDAY INTO THE 40S
TO ACCOUNT FOR SOME LINGERING CLOUDINESS AND WEAK CAA ASSOCIATED
WITH THE PASSING MAIN UPPER TROUGH.
THE FLOW ALOFT BECOMES ZONAL THE FIRST HALF OF THIS WEEK HEADING
INTO THE NEW YEAR. AN ELONGATED SHORTWAVE TROUGH WILL DIG SOUTHWEST
ACROSS THE GREAT BASIN OF NEVADA/UTAH/ARIZONA DURING THIS TIME. AT
THE SURFACE...RETURNING SOUTHERLY WINDS WILL WARM IT UP BRIEFLY ON
MONDAY TO BETWEEN 55 AND 65 DEGREES...BEFORE A SHALLOW ARCTIC COLD
FRONT ARRIVES EARLY TUESDAY. THOUGH CHILLY AND BRISK CONDITIONS
ARRIVE FOR THE MIDDLE PART OF THE WEEK...A BULK OF THE BETTER RAIN
CHANCES WILL REMAIN SOUTH AND WEST OF OUR AREA. THE ENERGY OUT
WEST IS STARTING TO SHOW SIGNS OF CLOSING OFF OVER ARIZONA BY
WEDNESDAY...BUT A LEAD SHORTWAVE WILL LIFT NORTHEAST OVER THE AREA
AND INDUCE ISENTROPIC ASCENT OVER THE SHALLOW ARCTIC AIR BY
WEDNESDAY NIGHT INTO THURSDAY WITH MODELS DIFFERING SOMEWHAT ON
ENVIRONMENTAL PROFILES...PRECIP TYPES...AND OVERALL TEMPERATURES.
SO CONFIDENCE ON THE OVERALL EVOLUTION OF ANY WINTER WEATHER
LATER IN THE WEEK REMAINS LOW...BUT APPEARS SOME CHANCE OF A MIX
WILL BE THERE WITH CHILLY CONDITIONS CONTINUING.
THE GREAT BASIN UPPER LOW WILL FINALLY BEGIN TO EJECT EAST TOWARD
AND ACROSS NORTH AND CENTRAL TEXAS AT THE END OF THE WEEK...AS
ANOTHER STRONG SHORTWAVE DROPS OVER THE PACIFIC NORTHWEST. MEDIUM
RANGE MODELS REALLY BEGIN DIVERGING BY FRIDAY INTO SATURDAY AS THE
OPEN TROUGH LIFTS ACROSS THE SOUTHERN PLAINS. THE GFS IS MUCH
QUICKER AND NORTH WITH IT...WHILE THE EUROPEAN SLOWER AND FURTHER
SOUTH. WITH THE SOUTHEASTERN U.S UPPER HIGH REMAINING RELATIVELY
STRONG OVER THE GULF OF MEXICO AND FLORIDA...THE EUROPEAN MODEL
SOLUTION APPEARS MORE LIKELY WITH GRADUAL MODERATING TEMPERATURES
AND CHANCES FOR RAIN AND THUNDERSTORMS THURSDAY NIGHT THROUGH
SATURDAY MORNING. WE SHOULD KNOW MORE ON DETAILS OF FUTURE SYSTEMS
IN THE COMING DAYS...BUT UNTIL THEN WE WILL JUST REMAIN
CONSERVATIVE UNTIL THEY BECOME MORE CLEAR.
05/
&&
.AVIATION...
AS /ISSUED 208 PM CST SAT DEC 27 2014/
LOOKS LIKE THE SHOWERS MOISTENED UP THE LOWER LEVELS ENOUGH FOR
MVFR CEILINGS. THEY SHOULD PERSIST UNTIL THE DRIER NEAR THE LINE
FROM WICHITA FALLS TO OKLAHOMA CITY GETS INTO THE AREA MID EVENING.
84
/PREVIOUS AVIATION DISCUSSION/
12Z GFS/NAM AND THEIR MOS CAME IN DRIER TODAY...BUT I AM LOOKING
AT THE PRECIP BAND WEST OF THE METROPLEX AND IT EXTRAPOLATES INTO
THE TAF SITES MID AFTERNOON. HRRR WEAKENS PRECIP BUT CONTINUES
IT. GIVEN WHAT I SEE TO OUR WEST I THINK THERE WILL BE SOME
PRECIP AT THE METROPLEX AIRPORTS. LIGHT SHOWERS ARE ALSO
INCREASING EAST OF THE BAND...AND I STARTED THE TAFS OUT WITH
VCSH. 850MB TEMPS ARE PROGGED TO REMAIN WARMER THAN FARTHER
WEST...SO I DO NOT SEE ANY PRECIP TYPES OTHER THAN RAIN. AS THE
SUPPORTING SHORT WAVE MOVES NORTHEAST...LOWER LEVELS WILL DRY OUT
AND I DROPPED THE RAIN AFTER SUNSET. 84
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 33 49 33 58 33 / 20 5 0 0 0
WACO, TX 35 50 31 61 34 / 20 10 0 0 0
PARIS, TX 33 48 31 55 31 / 30 5 0 0 0
DENTON, TX 31 49 32 57 29 / 20 5 0 0 0
MCKINNEY, TX 32 48 32 57 30 / 20 5 0 0 0
DALLAS, TX 34 49 34 59 34 / 20 5 0 0 0
TERRELL, TX 34 49 32 58 34 / 30 5 0 0 0
CORSICANA, TX 36 50 33 60 35 / 30 20 0 0 0
TEMPLE, TX 35 50 32 62 34 / 20 20 0 0 0
MINERAL WELLS, TX 29 49 31 58 28 / 10 5 0 0 0
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
05/
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
208 PM CST SAT DEC 27 2014
.AVIATION...
LOOKS LIKE THE SHOWERS MOISTENED UP THE LOWER LEVELS ENOUGH FOR
MVFR CEILINGS. THEY SHOULD PERSIST UNTIL THE DRIER NEAR THE LINE
FROM WICHITA FALLS TO OKLAHOMA CITY GETS INTO THE AREA MID EVENING.
84
/PREVIOUS AVIATION DISCUSSION/
12Z GFS/NAM AND THEIR MOS CAME IN DRIER TODAY...BUT I AM LOOKING
AT THE PRECIP BAND WEST OF THE METROPLEX AND IT EXTRAPOLATES INTO
THE TAF SITES MID AFTERNOON. HRRR WEAKENS PRECIP BUT CONTINUES
IT. GIVEN WHAT I SEE TO OUR WEST I THINK THERE WILL BE SOME
PRECIP AT THE METROPLEX AIRPORTS. LIGHT SHOWERS ARE ALSO
INCREASING EAST OF THE BAND...AND I STARTED THE TAFS OUT WITH
VCSH. 850MB TEMPS ARE PROGGED TO REMAIN WARMER THAN FARTHER
WEST...SO I DO NOT SEE ANY PRECIP TYPES OTHER THAN RAIN. AS THE
SUPPORTING SHORT WAVE MOVES NORTHEAST...LOWER LEVELS WILL DRY OUT
AND I DROPPED THE RAIN AFTER SUNSET. 84
&&
.UPDATE...
WE HAVE DECIDED TO ISSUE A WINTER WEATHER ADVISORY FOR LIGHT
SNOW...POSSIBLY MIXED WITH LIGHT SLEET AT TIMES ACROSS NORTHERN
STEPHENS...YOUNG...JACK...AND MONTAGUE COUNTIES THROUGH MID
AFTERNOON. COLD AIR NOW IS ENTRENCHED ACROSS ALL OF NORTH TEXAS
WITH THE COLDEST TEMPERATURES JUST ABOVE FREEZING ACROSS OUR FAR
NORTHWEST COUNTIES. A SHORTWAVE DISTURBANCE LIFTING NORTHEAST OUT
OF THE WESTERN CONUS MAIN LONGWAVE TROUGH IS INCREASING THE THE
MID LEVEL FRONTOGENETICAL FORCING ACROSS THE NORTHWEST COUNTIES.
SEVERAL REPORTS OF LIGHT SNOW WITH SOME SLEET HAVE OCCURRED ACROSS
YOUNG COUNTY WHERE BANDING IS NOTED ON REGIONAL RADAR. LOCAL
LAPS AND RUC SOUNDINGS ACROSS THIS REGION INDICATE POTENTIAL FOR
LIGHT SNOW AND SLEET TO CONTINUE NEXT FEW HOURS WITH A NORTHEAST
TRAJECTORY.
IN ADDITION...THIS IS A HIGH TRAVEL-VOLUME DAY AFTER THE HOLIDAYS
AND WILL GIVE COMMUTERS HEADING NORTHEAST TOWARD THIS AREA SOME
INDICATION OF SLICK SPOTS...ESPECIALLY ON BRIDGES...OVERPASSES...
AND SECONDARY ROADS.
05/
&&
.PREV DISCUSSION... /ISSUED 442 AM CST SAT DEC 27 2014/
THE FIRST OF THREE COLD FRONTS THAT WILL AFFECT THE REGION OVER
THE NEXT 7-8 DAYS IS CURRENTLY MOVING THROUGH NORTH CENTRAL TEXAS.
AT 320 AM...THE FRONT WAS ROUGHLY ALONG A LINE FROM PARIS TO
DALLAS TO GOLDTHWAITE. AROUND MID MORNING...THE FRONT WILL HAVE
TRAVERSED OUR ENTIRE CWA...MOVING SOUTH AND SOUTHEAST. TEMPERATURES
BEHIND THE FRONT HAVE FALLEN INTO THE 40S WHILE TEMPERATURES AHEAD
OF THE FRONT REMAIN IN THE 60S. MOST LOCATIONS WILL EXPERIENCE
THEIR DAYTIME HIGHS NEAR DAYBREAK WITH SLOWLY FALLING TEMPERATURES
THROUGHOUT THE DAY. HOWEVER...AFTERNOON TEMPERATURES ACROSS OUR
NORTHWESTERN COUNTIES WILL LIKELY REMAIN NEARLY STEADY...POSSIBLY
CREEPING UP A DEGREE OR TWO...BEFORE BEGINNING TO FALL AGAIN AROUND
SUNSET THIS EVENING. THE REGION WILL REMAIN OVERCAST/CLOUDY TODAY
WITH SOME CLEARING ACROSS THE WEST THIS EVENING AND TONIGHT.
HOWEVER...HIGH CLOUDS WILL BEGIN MOVING IN FROM THE WEST WHICH
CREATES A CHALLENGE FOR OVERNIGHT LOWS. THE HIGH CLOUD COVER
SHOULD KEEP OVERNIGHT LOWS FROM FULLY FALLING AS MUCH AS THEY
WOULD UNDER CLEARER SKIES...BUT STILL EXPECT A MUCH COLDER NIGHT
WITH OVERNIGHT LOWS IN THE UPPER 20S NORTHWEST TO UPPER 30S IN THE
SOUTHEAST WHERE DENSE CLOUD COVER WILL PREVAIL.
ONGOING SHOWERS THIS MORNING WILL CONTINUE THROUGH THE DAY AS LIFT
FROM AN UPPER LEVEL TROUGH TO OUR WEST CONTINUES ACROSS THE
REGION. WHILE THERE COULD BE A FEW RUMBLES OF THUNDER AT
TIMES...HAVE LEFT THE THUNDER MENTION OUT OF THE FORECAST FOR NOW
AS THE ELEVATED INSTABILITY IS PRETTY MINIMAL. MOST OF THE AREA
WILL RECEIVE LESS THAN A QUARTER OF AN INCH OF RAIN TODAY...WITH
SOME ISOLATED HIGHER AMOUNTS. MOST THE PRECIPITATION WILL END THIS
EVENING BUT SOME ADDITIONAL SHOWERS MAY OCCUR SUNDAY MORNING
ACROSS OUR SOUTHERN COUNTIES AS THE UPPER LEVEL TROUGH SWINGS
THROUGH THE REGION. WE WILL SEE WARMING TEMPERATURES SUNDAY
THROUGH MONDAY AS WE AWAIT OUR NEXT SYSTEM.
THE NEXT SYSTEM CONTINUES TO BE A DEEPENING TROUGH OVER THE WEST
COAST NEXT WEEK. THIS TROUGH IS CURRENTLY LOCATED OFF THE COAST
OF BRITISH COLUMBIA AND WILL CONTINUE A SOUTHWARD TRACK FOR THE
NEXT SEVERAL DAYS. AS THIS TROUGH DEVELOPS...IT WILL MAINTAIN A
BROAD LATITUDINAL ORIENTATION OR POSITIVE TILT...WHICH RESULTS IN
NEAR ZONAL FLOW ACROSS A GOOD MAJORITY OF THE COUNTRY. THIS
ORIENTATION WILL ALLOW COLD ARCTIC AIR AT THE SURFACE TO RUSH OUT
OF CANADA...INTO THE PLAINS...AND DOWN THROUGH TEXAS. THE ARCTIC
FRONT SHOULD NOT MEET MUCH RESISTANCE MOVING SOUTH AND IS EXPECTED
TO ARRIVE HERE MONDAY NIGHT/TUESDAY MORNING. THE FRONT IS NOT
EXPECTED TO QUICKLY AND AGGRESSIVELY MOVE THROUGH THE REGION...BUT
WILL INSTEAD GRADUALLY SPREAD ACROSS THE REGION WITH NOTICEABLY
COLDER TEMPERATURES BEHIND THE FRONT. THE 1055 MB PLUS SURFACE
HIGH BEHIND THE FRONT WILL TAKE A FEW DAYS TO MOVE INTO THE
SOUTHERN PLAINS...MEANING THE COLD WEATHER WILL BE AROUND FOR A
FEW DAYS. ON TUESDAY...HIGHS WILL RANGE FROM THE MID 30S IN THE
NORTHWEST TO LOWER 50S IN THE SOUTHEAST. HIGH TEMPERATURES ON
WEDNESDAY WILL ONLY BE IN THE 30S AND LOWER 40S...WITH THE
NORTHWEST STRUGGLING TO REACH ABOVE FREEZING. LOW TEMPERATURES
TUESDAY AND WEDNESDAY NIGHTS WILL BE IN THE 20S AND 30S.
STRENGTHENING WARM AIR ADVECTION WILL ACTUALLY WARM OVERNIGHT
TEMPERATURES WEDNESDAY NIGHT/THURSDAY MORNING BUT LOWS THAT NIGHT
WILL STILL BE IN THE 20S AND 30S...AND HIGHS ON THURSDAY WILL
REMAIN IN THE 30S AND LOWER 40S DUE TO CLOUD COVER AND RAIN.
OUR MAIN CONCERN AND CHALLENGE WITH THIS SYSTEM IS THE POTENTIAL
FOR PRECIPITATION AND ESPECIALLY FROZEN PRECIPITATION. THE UPPER
LEVEL TROUGH WILL CUT OFF INTO A LOW OVER CALIFORNIA ON WEDNESDAY.
WHEN AN UPPER LEVEL LOW CUTS OFF...IT BECOMES SEPARATED FROM THE
MAIN JET STREAM AND WILL TEND TO SLOW DOWN ITS TREK AS A RESULT.
THIS IS INDICATED IN THE MODELS AS THE LOW SLOWS DOWN AND REMAINS
OVER THE SOUTHWESTERN CONUS THROUGH FRIDAY. WITH THE UPPER LEVEL
LOW WELL TO OUR WEST...TEXAS REMAINS IN A NEARLY ZONAL AND/OR
SLIGHTLY RIDGED PATTERN ALOFT. IN THIS PATTERN...THERE IS GENERALLY
A LACK OF LARGE SCALE LIFT ACROSS THE REGION SO WE HAVE TO LOOK
CLOSER AT SMALLER SCALE FEATURES FOR ANY LIFT FOR PRECIPITATION
DEVELOPMENT.
THE FRONT IS EXPECTED TO COME THROUGH DRY AND THE MODELS HAVE
CONSISTENTLY INDICATED NO PRECIPITATION ALONG THE FRONT.
HOWEVER...AS AN H850 HIGH MOVES INTO THE REGION TUESDAY NIGHT AND
WEDNESDAY...IT TURNS THE 850 MB WINDS ACROSS OUR SOUTHWESTERN AND
WESTERN COUNTIES TO THE SOUTH WHICH RESULTS IN SOME WEAK WARM AIR
ADVECTION OVER THE COLD SURFACE LAYER. DO NOT THINK THE WARM AIR
ADVECTION WILL BE STRONG ENOUGH TO GENERATE MUCH PRECIPITATION BUT
THERE IS STILL A SMALL CHANCE IT COULD DEVELOP SOME LIGHT
PRECIPITATION AND WILL RETAIN THE LOW POPS IN THE SOUTHWEST
TUESDAY NIGHT AND IN THE WEST WEDNESDAY WITH A MENTION OF LIGHT
DRIZZLE/FREEZING DRIZZLE. CONFIDENCE IS LOW THIS WILL OCCUR...BUT
IF IT DOES...VERY LIGHT ACCUMULATIONS OF ICE MAY OCCUR ON ELEVATED
SURFACES...WINDSHIELDS...AND POSSIBLY TREE BRANCHES. WE ARE
TRYING TO ANTICIPATE SMALLER SCALE FEATURES SEVERAL DAYS IN
ADVANCE WHICH IS DIFFICULT TO DO...SO WE WANT TO EMPHASIS THAT THE
CHANCES FOR FROZEN PRECIPITATION REMAIN LOW AND WILL CONTINUE TO
MONITOR THIS TIME PERIOD IN FUTURE FORECAST RUNS.
BETTER PRECIPITATION CHANCES ARE EXPECTED THURSDAY THROUGH FRIDAY
AS THE UPPER LEVEL LOW BEGINS MOVING EAST AND INCREASES LIFT
ACROSS THE REGION. WARM AIR ADVECTION AND ISENTROPIC LIFT WILL
START TO INCREASE LATE WEDNESDAY NIGHT AND THURSDAY
MORNING...CONTINUING THROUGH THE DAY ON THURSDAY. IN THIS
REGIME...PRECIPITATION WILL LIKELY DEVELOP FROM SOUTH TO NORTH
ACROSS THE REGION. EVEN THOUGH TEMPERATURES WILL LIKELY BE RISING
FOR PART OF THE NIGHT...THERE WILL STILL BE A PERIOD WHERE
TEMPERATURES WILL BE SLIGHTLY BELOW FREEZING ACROSS OUR WESTERN
COUNTIES AND THESE AREAS COULD SEE LIGHT FREEZING RAIN FOR A FEW
HOURS. IMPACTS SHOULD BE VERY MINIMAL DURING THE PERIOD OF
FREEZING RAIN AS TEMPERATURES ARE EXPECTED TO BE IN THE LOWER 30S
AND FREEZING RAIN USUALLY DOES NOT START TO HAVE A SIGNIFICANT
IMPACT...ESPECIALLY ON ROADS...UNLESS TEMPERATURES ARE IN THE
UPPER 20S. HOWEVER...WE WILL HAVE TO MONITOR CHANGES TO THE
TEMPERATURE FORECAST THAT NIGHT. BUT WITH INCREASING TEMPERATURES
THROUGH THE NIGHT...THE WARMING TEMPERATURES AND CHANGEOVER TO
LIQUID RAIN WILL ACT TO MELT ANY ICE LATER IN THE NIGHT.
A COLD...BUT ALL LIQUID...RAIN IS EXPECTED TO BE MORE WIDESPREAD
THURSDAY THROUGH FRIDAY. HAVE INCREASED POPS IN THIS TIME FRAME
WITH THE MODEL QPF INDICATING SOME BENEFICIAL RAIN IS POSSIBLE.
THERE COULD BE TWO ROUNDS OF RAIN DURING THIS TIME...ONE ON
THURSDAY AND ANOTHER ON FRIDAY. ANOTHER COLD FRONT IS POSSIBLE
FRIDAY OR SATURDAY.
82/JLD
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 32 50 33 58 33 / 20 5 5 5 5
WACO, TX 34 49 32 61 34 / 20 10 5 5 5
PARIS, TX 33 49 32 55 31 / 30 5 5 5 5
DENTON, TX 29 50 32 57 29 / 20 5 5 5 5
MCKINNEY, TX 31 49 32 57 30 / 20 5 5 5 5
DALLAS, TX 33 50 34 59 34 / 20 5 5 5 5
TERRELL, TX 34 50 32 58 34 / 30 5 5 5 5
CORSICANA, TX 35 49 33 60 35 / 30 10 5 5 5
TEMPLE, TX 34 49 32 61 34 / 20 20 5 5 5
MINERAL WELLS, TX 28 49 31 58 28 / 10 5 5 5 5
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 3 PM CST THIS AFTERNOON FOR TXZ091-
100-101-115.
&&
$$
/
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
1137 AM CST SAT DEC 27 2014
.AVIATION...
12Z GFS/NAM AND THEIR MOS CAME IN DRIER TODAY...BUT I AM LOOKING
AT THE PRECIP BAND WEST OF THE METROPLEX AND IT EXTRAPOLATES INTO
THE TAF SITES MID AFTERNOON. HRRR WEAKENS PRECIP BUT CONTINUES
IT. GIVEN WHAT I SEE TO OUR WEST I THINK THERE WILL BE SOME
PRECIP AT THE METROPLEX AIRPORTS. LIGHT SHOWERS ARE ALSO
INCREASING EAST OF THE BAND...AND I STARTED THE TAFS OUT WITH
VCSH. 850MB TEMPS ARE PROGGED TO REMAIN WARMER THAN FARTHER
WEST...SO I DO NOT SEE ANY PRECIP TYPES OTHER THAN RAIN. AS THE
SUPPORTING SHORT WAVE MOVES NORTHEAST...LOWER LEVELS WILL DRY OUT
AND I DROPPED THE RAIN AFTER SUNSET. 84
&&
.UPDATE...
WE HAVE DECIDED TO ISSUE A WINTER WEATHER ADVISORY FOR LIGHT
SNOW...POSSIBLY MIXED WITH LIGHT SLEET AT TIMES ACROSS NORTHERN
STEPHENS...YOUNG...JACK...AND MONTAGUE COUNTIES THROUGH MID
AFTERNOON. COLD AIR NOW IS ENTRENCHED ACROSS ALL OF NORTH TEXAS
WITH THE COLDEST TEMPERATURES JUST ABOVE FREEZING ACROSS OUR FAR
NORTHWEST COUNTIES. A SHORTWAVE DISTURBANCE LIFTING NORTHEAST OUT
OF THE WESTERN CONUS MAIN LONGWAVE TROUGH IS INCREASING THE THE
MID LEVEL FRONTOGENETICAL FORCING ACROSS THE NORTHWEST COUNTIES.
SEVERAL REPORTS OF LIGHT SNOW WITH SOME SLEET HAVE OCCURRED ACROSS
YOUNG COUNTY WHERE BANDING IS NOTED ON REGIONAL RADAR. LOCAL
LAPS AND RUC SOUNDINGS ACROSS THIS REGION INDICATE POTENTIAL FOR
LIGHT SNOW AND SLEET TO CONTINUE NEXT FEW HOURS WITH A NORTHEAST
TRAJECTORY.
IN ADDITION...THIS IS A HIGH TRAVEL-VOLUME DAY AFTER THE HOLIDAYS
AND WILL GIVE COMMUTERS HEADING NORTHEAST TOWARD THIS AREA SOME
INDICATION OF SLICK SPOTS...ESPECIALLY ON BRIDGES...OVERPASSES...
AND SECONDARY ROADS.
05/
&&
.PREV DISCUSSION... /ISSUED 442 AM CST SAT DEC 27 2014/
THE FIRST OF THREE COLD FRONTS THAT WILL AFFECT THE REGION OVER
THE NEXT 7-8 DAYS IS CURRENTLY MOVING THROUGH NORTH CENTRAL TEXAS.
AT 320 AM...THE FRONT WAS ROUGHLY ALONG A LINE FROM PARIS TO
DALLAS TO GOLDTHWAITE. AROUND MID MORNING...THE FRONT WILL HAVE
TRAVERSED OUR ENTIRE CWA...MOVING SOUTH AND SOUTHEAST. TEMPERATURES
BEHIND THE FRONT HAVE FALLEN INTO THE 40S WHILE TEMPERATURES AHEAD
OF THE FRONT REMAIN IN THE 60S. MOST LOCATIONS WILL EXPERIENCE
THEIR DAYTIME HIGHS NEAR DAYBREAK WITH SLOWLY FALLING TEMPERATURES
THROUGHOUT THE DAY. HOWEVER...AFTERNOON TEMPERATURES ACROSS OUR
NORTHWESTERN COUNTIES WILL LIKELY REMAIN NEARLY STEADY...POSSIBLY
CREEPING UP A DEGREE OR TWO...BEFORE BEGINNING TO FALL AGAIN AROUND
SUNSET THIS EVENING. THE REGION WILL REMAIN OVERCAST/CLOUDY TODAY
WITH SOME CLEARING ACROSS THE WEST THIS EVENING AND TONIGHT.
HOWEVER...HIGH CLOUDS WILL BEGIN MOVING IN FROM THE WEST WHICH
CREATES A CHALLENGE FOR OVERNIGHT LOWS. THE HIGH CLOUD COVER
SHOULD KEEP OVERNIGHT LOWS FROM FULLY FALLING AS MUCH AS THEY
WOULD UNDER CLEARER SKIES...BUT STILL EXPECT A MUCH COLDER NIGHT
WITH OVERNIGHT LOWS IN THE UPPER 20S NORTHWEST TO UPPER 30S IN THE
SOUTHEAST WHERE DENSE CLOUD COVER WILL PREVAIL.
ONGOING SHOWERS THIS MORNING WILL CONTINUE THROUGH THE DAY AS LIFT
FROM AN UPPER LEVEL TROUGH TO OUR WEST CONTINUES ACROSS THE
REGION. WHILE THERE COULD BE A FEW RUMBLES OF THUNDER AT
TIMES...HAVE LEFT THE THUNDER MENTION OUT OF THE FORECAST FOR NOW
AS THE ELEVATED INSTABILITY IS PRETTY MINIMAL. MOST OF THE AREA
WILL RECEIVE LESS THAN A QUARTER OF AN INCH OF RAIN TODAY...WITH
SOME ISOLATED HIGHER AMOUNTS. MOST THE PRECIPITATION WILL END THIS
EVENING BUT SOME ADDITIONAL SHOWERS MAY OCCUR SUNDAY MORNING
ACROSS OUR SOUTHERN COUNTIES AS THE UPPER LEVEL TROUGH SWINGS
THROUGH THE REGION. WE WILL SEE WARMING TEMPERATURES SUNDAY
THROUGH MONDAY AS WE AWAIT OUR NEXT SYSTEM.
THE NEXT SYSTEM CONTINUES TO BE A DEEPENING TROUGH OVER THE WEST
COAST NEXT WEEK. THIS TROUGH IS CURRENTLY LOCATED OFF THE COAST
OF BRITISH COLUMBIA AND WILL CONTINUE A SOUTHWARD TRACK FOR THE
NEXT SEVERAL DAYS. AS THIS TROUGH DEVELOPS...IT WILL MAINTAIN A
BROAD LATITUDINAL ORIENTATION OR POSITIVE TILT...WHICH RESULTS IN
NEAR ZONAL FLOW ACROSS A GOOD MAJORITY OF THE COUNTRY. THIS
ORIENTATION WILL ALLOW COLD ARCTIC AIR AT THE SURFACE TO RUSH OUT
OF CANADA...INTO THE PLAINS...AND DOWN THROUGH TEXAS. THE ARCTIC
FRONT SHOULD NOT MEET MUCH RESISTANCE MOVING SOUTH AND IS EXPECTED
TO ARRIVE HERE MONDAY NIGHT/TUESDAY MORNING. THE FRONT IS NOT
EXPECTED TO QUICKLY AND AGGRESSIVELY MOVE THROUGH THE REGION...BUT
WILL INSTEAD GRADUALLY SPREAD ACROSS THE REGION WITH NOTICEABLY
COLDER TEMPERATURES BEHIND THE FRONT. THE 1055 MB PLUS SURFACE
HIGH BEHIND THE FRONT WILL TAKE A FEW DAYS TO MOVE INTO THE
SOUTHERN PLAINS...MEANING THE COLD WEATHER WILL BE AROUND FOR A
FEW DAYS. ON TUESDAY...HIGHS WILL RANGE FROM THE MID 30S IN THE
NORTHWEST TO LOWER 50S IN THE SOUTHEAST. HIGH TEMPERATURES ON
WEDNESDAY WILL ONLY BE IN THE 30S AND LOWER 40S...WITH THE
NORTHWEST STRUGGLING TO REACH ABOVE FREEZING. LOW TEMPERATURES
TUESDAY AND WEDNESDAY NIGHTS WILL BE IN THE 20S AND 30S.
STRENGTHENING WARM AIR ADVECTION WILL ACTUALLY WARM OVERNIGHT
TEMPERATURES WEDNESDAY NIGHT/THURSDAY MORNING BUT LOWS THAT NIGHT
WILL STILL BE IN THE 20S AND 30S...AND HIGHS ON THURSDAY WILL
REMAIN IN THE 30S AND LOWER 40S DUE TO CLOUD COVER AND RAIN.
OUR MAIN CONCERN AND CHALLENGE WITH THIS SYSTEM IS THE POTENTIAL
FOR PRECIPITATION AND ESPECIALLY FROZEN PRECIPITATION. THE UPPER
LEVEL TROUGH WILL CUT OFF INTO A LOW OVER CALIFORNIA ON WEDNESDAY.
WHEN AN UPPER LEVEL LOW CUTS OFF...IT BECOMES SEPARATED FROM THE
MAIN JET STREAM AND WILL TEND TO SLOW DOWN ITS TREK AS A RESULT.
THIS IS INDICATED IN THE MODELS AS THE LOW SLOWS DOWN AND REMAINS
OVER THE SOUTHWESTERN CONUS THROUGH FRIDAY. WITH THE UPPER LEVEL
LOW WELL TO OUR WEST...TEXAS REMAINS IN A NEARLY ZONAL AND/OR
SLIGHTLY RIDGED PATTERN ALOFT. IN THIS PATTERN...THERE IS GENERALLY
A LACK OF LARGE SCALE LIFT ACROSS THE REGION SO WE HAVE TO LOOK
CLOSER AT SMALLER SCALE FEATURES FOR ANY LIFT FOR PRECIPITATION
DEVELOPMENT.
THE FRONT IS EXPECTED TO COME THROUGH DRY AND THE MODELS HAVE
CONSISTENTLY INDICATED NO PRECIPITATION ALONG THE FRONT.
HOWEVER...AS AN H850 HIGH MOVES INTO THE REGION TUESDAY NIGHT AND
WEDNESDAY...IT TURNS THE 850 MB WINDS ACROSS OUR SOUTHWESTERN AND
WESTERN COUNTIES TO THE SOUTH WHICH RESULTS IN SOME WEAK WARM AIR
ADVECTION OVER THE COLD SURFACE LAYER. DO NOT THINK THE WARM AIR
ADVECTION WILL BE STRONG ENOUGH TO GENERATE MUCH PRECIPITATION BUT
THERE IS STILL A SMALL CHANCE IT COULD DEVELOP SOME LIGHT
PRECIPITATION AND WILL RETAIN THE LOW POPS IN THE SOUTHWEST
TUESDAY NIGHT AND IN THE WEST WEDNESDAY WITH A MENTION OF LIGHT
DRIZZLE/FREEZING DRIZZLE. CONFIDENCE IS LOW THIS WILL OCCUR...BUT
IF IT DOES...VERY LIGHT ACCUMULATIONS OF ICE MAY OCCUR ON ELEVATED
SURFACES...WINDSHIELDS...AND POSSIBLY TREE BRANCHES. WE ARE
TRYING TO ANTICIPATE SMALLER SCALE FEATURES SEVERAL DAYS IN
ADVANCE WHICH IS DIFFICULT TO DO...SO WE WANT TO EMPHASIS THAT THE
CHANCES FOR FROZEN PRECIPITATION REMAIN LOW AND WILL CONTINUE TO
MONITOR THIS TIME PERIOD IN FUTURE FORECAST RUNS.
BETTER PRECIPITATION CHANCES ARE EXPECTED THURSDAY THROUGH FRIDAY
AS THE UPPER LEVEL LOW BEGINS MOVING EAST AND INCREASES LIFT
ACROSS THE REGION. WARM AIR ADVECTION AND ISENTROPIC LIFT WILL
START TO INCREASE LATE WEDNESDAY NIGHT AND THURSDAY
MORNING...CONTINUING THROUGH THE DAY ON THURSDAY. IN THIS
REGIME...PRECIPITATION WILL LIKELY DEVELOP FROM SOUTH TO NORTH
ACROSS THE REGION. EVEN THOUGH TEMPERATURES WILL LIKELY BE RISING
FOR PART OF THE NIGHT...THERE WILL STILL BE A PERIOD WHERE
TEMPERATURES WILL BE SLIGHTLY BELOW FREEZING ACROSS OUR WESTERN
COUNTIES AND THESE AREAS COULD SEE LIGHT FREEZING RAIN FOR A FEW
HOURS. IMPACTS SHOULD BE VERY MINIMAL DURING THE PERIOD OF
FREEZING RAIN AS TEMPERATURES ARE EXPECTED TO BE IN THE LOWER 30S
AND FREEZING RAIN USUALLY DOES NOT START TO HAVE A SIGNIFICANT
IMPACT...ESPECIALLY ON ROADS...UNLESS TEMPERATURES ARE IN THE
UPPER 20S. HOWEVER...WE WILL HAVE TO MONITOR CHANGES TO THE
TEMPERATURE FORECAST THAT NIGHT. BUT WITH INCREASING TEMPERATURES
THROUGH THE NIGHT...THE WARMING TEMPERATURES AND CHANGEOVER TO
LIQUID RAIN WILL ACT TO MELT ANY ICE LATER IN THE NIGHT.
A COLD...BUT ALL LIQUID...RAIN IS EXPECTED TO BE MORE WIDESPREAD
THURSDAY THROUGH FRIDAY. HAVE INCREASED POPS IN THIS TIME FRAME
WITH THE MODEL QPF INDICATING SOME BENEFICIAL RAIN IS POSSIBLE.
THERE COULD BE TWO ROUNDS OF RAIN DURING THIS TIME...ONE ON
THURSDAY AND ANOTHER ON FRIDAY. ANOTHER COLD FRONT IS POSSIBLE
FRIDAY OR SATURDAY.
82/JLD
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 42 32 50 33 58 / 40 20 5 5 5
WACO, TX 46 34 49 32 61 / 40 20 10 5 5
PARIS, TX 43 33 49 32 55 / 40 30 5 5 5
DENTON, TX 40 29 50 32 57 / 50 20 5 5 5
MCKINNEY, TX 41 31 49 32 57 / 40 20 5 5 5
DALLAS, TX 43 33 50 34 59 / 40 20 5 5 5
TERRELL, TX 45 34 50 32 58 / 40 30 5 5 5
CORSICANA, TX 47 35 49 33 60 / 40 30 10 5 5
TEMPLE, TX 46 34 49 32 61 / 40 20 20 5 5
MINERAL WELLS, TX 41 28 49 31 58 / 60 10 5 5 5
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 3 PM CST THIS AFTERNOON FOR TXZ091-
100-101-115.
&&
$$
/
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1111 AM CST SAT DEC 27 2014
.UPDATE...
WE HAVE DECIDED TO ISSUE A WINTER WEATHER ADVISORY FOR LIGHT
SNOW...POSSIBLY MIXED WITH LIGHT SLEET AT TIMES ACROSS NORTHERN
STEPHENS...YOUNG...JACK...AND MONTAGUE COUNTIES THROUGH MID
AFTERNOON. COLD AIR NOW IS ENTRENCHED ACROSS ALL OF NORTH TEXAS
WITH THE COLDEST TEMPERATURES JUST ABOVE FREEZING ACROSS OUR FAR
NORTHWEST COUNTIES. A SHORTWAVE DISTURBANCE LIFTING NORTHEAST OUT
OF THE WESTERN CONUS MAIN LONGWAVE TROUGH IS INCREASING THE THE
MID LEVEL FRONTOGENETICAL FORCING ACROSS THE NORTHWEST COUNTIES.
SEVERAL REPORTS OF LIGHT SNOW WITH SOME SLEET HAVE OCCURRED ACROSS
YOUNG COUNTY WHERE BANDING IS NOTED ON REGIONAL RADAR. LOCAL
LAPS AND RUC SOUNDINGS ACROSS THIS REGION INDICATE POTENTIAL FOR
LIGHT SNOW AND SLEET TO CONTINUE NEXT FEW HOURS WITH A NORTHEAST
TRAJECTORY.
IN ADDITION...THIS IS A HIGH TRAVEL-VOLUME DAY AFTER THE HOLIDAYS
AND WILL GIVE COMMUTERS HEADING NORTHEAST TOWARD THIS AREA SOME
INDICATION OF SLICK SPOTS...ESPECIALLY ON BRIDGES...OVERPASSES...
AND SECONDARY ROADS.
05/
&&
.AVIATION...
/ISSUED 553 AM CST SAT DEC 27 2014/
A COLD FRONT HAD MOVED THROUGH ALL TAF SITES AS OF 530 AM. THE
PASSAGE OF THE FRONT BROUGHT DRIER AIR AND LIFTING CEILINGS. MVFR
CONDITIONS WILL PREVAIL THROUGH SUNRISE WITH CEILINGS LIFTING
ABOVE 3000 FT BY MID TO LATE MORNING. SCATTERED LIGHT SHOWERS ARE
POSSIBLE THROUGH THE MORNING BUT THE BETTER RAIN CHANCES WILL
ARRIVE THIS AFTERNOON AS LARGE SCALE LIFT ASSOCIATED WITH A
APPROACHING UPPER TROUGH INCREASES. ANY SHOWERS THAT DEVELOP THIS
AFTERNOON WILL BE RELATIVELY LIGHT BUT MAY BE ACCOMPANIED BY MVFR
CEILINGS. A FEW SHOWERS COULD LINGER OVERNIGHT BUT COVERAGE WILL
BE TOO LIMITED TO INCLUDE IN THIS FORECAST. VFR CONDITIONS WILL PREVAIL
TONIGHT WITH SCATTERED TO BROKEN MIDDLE AND UPPER LEVEL CLOUDS.
A NORTH WIND WILL PREVAIL BETWEEN 16 AND 20 KNOTS TODAY WITH SOME
GUSTS UP TO ABOUT 27 KNOTS. WIND SPEEDS SHOULD FALL BELOW 15 KNOTS
BY MID EVENING.
79
&&
.PREV UPDATE...
.UPDATE...
MINOR UPDATE TO ADJUST AND CLEAN UP POPS AND CHANCES. A FEW
REPORTS OF WINTRY MIX OF WINTER PRECIPITATION ACROSS WESTERN YOUNG
AND STEPHENS COUNTIES...BUT TEMPERATURES ARE IN THE MID 30S AND
ROADS ARE MOSTLY WET...THOUGH ELEVATED SURFACES HAVE TO BE
WATCHED OUT THAT WAY. DUE TO LIMITED...IF ANY IMPACTS...WE DO NOT
PLAN ON ISSUING ANY ADVISORIES THROUGH TODAY AS THIS SHORTWAVE
LIFTS OUT READILY TO THE NORTHEAST AND TEMPERATURES REMAIN MOSTLY
STEADY STATE. WE WILL BE WATCHING FOR ANY POSSIBLE WET-BULB
EFFECTS HOWEVER TO THE NORTHWEST OF THE DFW METRO.
OTHERWISE...A FEW ELEVATED SHOWERS AND STORMS ABOVE THE FRONTAL
INVERSION ACROSS THE SOUTHEAST COUNTIES THROUGH THIS AFTERNOON.
CAN/T RULE OUT A LITTLE PEA HAIL WITH STRONGEST ACTIVITY. IT WILL
REMAIN MAINLY CLOUDY...WINDY AND COLD THROUGHOUT THE DAY WITH ONLY
A SLOW DROP IN TEMPS WITH CONTINUED CAA.
05/
&&
.PREV DISCUSSION... /ISSUED 442 AM CST SAT DEC 27 2014/
THE FIRST OF THREE COLD FRONTS THAT WILL AFFECT THE REGION OVER
THE NEXT 7-8 DAYS IS CURRENTLY MOVING THROUGH NORTH CENTRAL TEXAS.
AT 320 AM...THE FRONT WAS ROUGHLY ALONG A LINE FROM PARIS TO
DALLAS TO GOLDTHWAITE. AROUND MID MORNING...THE FRONT WILL HAVE
TRAVERSED OUR ENTIRE CWA...MOVING SOUTH AND SOUTHEAST. TEMPERATURES
BEHIND THE FRONT HAVE FALLEN INTO THE 40S WHILE TEMPERATURES AHEAD
OF THE FRONT REMAIN IN THE 60S. MOST LOCATIONS WILL EXPERIENCE
THEIR DAYTIME HIGHS NEAR DAYBREAK WITH SLOWLY FALLING TEMPERATURES
THROUGHOUT THE DAY. HOWEVER...AFTERNOON TEMPERATURES ACROSS OUR
NORTHWESTERN COUNTIES WILL LIKELY REMAIN NEARLY STEADY...POSSIBLY
CREEPING UP A DEGREE OR TWO...BEFORE BEGINNING TO FALL AGAIN AROUND
SUNSET THIS EVENING. THE REGION WILL REMAIN OVERCAST/CLOUDY TODAY
WITH SOME CLEARING ACROSS THE WEST THIS EVENING AND TONIGHT.
HOWEVER...HIGH CLOUDS WILL BEGIN MOVING IN FROM THE WEST WHICH
CREATES A CHALLENGE FOR OVERNIGHT LOWS. THE HIGH CLOUD COVER
SHOULD KEEP OVERNIGHT LOWS FROM FULLY FALLING AS MUCH AS THEY
WOULD UNDER CLEARER SKIES...BUT STILL EXPECT A MUCH COLDER NIGHT
WITH OVERNIGHT LOWS IN THE UPPER 20S NORTHWEST TO UPPER 30S IN THE
SOUTHEAST WHERE DENSE CLOUD COVER WILL PREVAIL.
ONGOING SHOWERS THIS MORNING WILL CONTINUE THROUGH THE DAY AS LIFT
FROM AN UPPER LEVEL TROUGH TO OUR WEST CONTINUES ACROSS THE
REGION. WHILE THERE COULD BE A FEW RUMBLES OF THUNDER AT
TIMES...HAVE LEFT THE THUNDER MENTION OUT OF THE FORECAST FOR NOW
AS THE ELEVATED INSTABILITY IS PRETTY MINIMAL. MOST OF THE AREA
WILL RECEIVE LESS THAN A QUARTER OF AN INCH OF RAIN TODAY...WITH
SOME ISOLATED HIGHER AMOUNTS. MOST THE PRECIPITATION WILL END THIS
EVENING BUT SOME ADDITIONAL SHOWERS MAY OCCUR SUNDAY MORNING
ACROSS OUR SOUTHERN COUNTIES AS THE UPPER LEVEL TROUGH SWINGS
THROUGH THE REGION. WE WILL SEE WARMING TEMPERATURES SUNDAY
THROUGH MONDAY AS WE AWAIT OUR NEXT SYSTEM.
THE NEXT SYSTEM CONTINUES TO BE A DEEPENING TROUGH OVER THE WEST
COAST NEXT WEEK. THIS TROUGH IS CURRENTLY LOCATED OFF THE COAST
OF BRITISH COLUMBIA AND WILL CONTINUE A SOUTHWARD TRACK FOR THE
NEXT SEVERAL DAYS. AS THIS TROUGH DEVELOPS...IT WILL MAINTAIN A
BROAD LATITUDINAL ORIENTATION OR POSITIVE TILT...WHICH RESULTS IN
NEAR ZONAL FLOW ACROSS A GOOD MAJORITY OF THE COUNTRY. THIS
ORIENTATION WILL ALLOW COLD ARCTIC AIR AT THE SURFACE TO RUSH OUT
OF CANADA...INTO THE PLAINS...AND DOWN THROUGH TEXAS. THE ARCTIC
FRONT SHOULD NOT MEET MUCH RESISTANCE MOVING SOUTH AND IS EXPECTED
TO ARRIVE HERE MONDAY NIGHT/TUESDAY MORNING. THE FRONT IS NOT
EXPECTED TO QUICKLY AND AGGRESSIVELY MOVE THROUGH THE REGION...BUT
WILL INSTEAD GRADUALLY SPREAD ACROSS THE REGION WITH NOTICEABLY
COLDER TEMPERATURES BEHIND THE FRONT. THE 1055 MB PLUS SURFACE
HIGH BEHIND THE FRONT WILL TAKE A FEW DAYS TO MOVE INTO THE
SOUTHERN PLAINS...MEANING THE COLD WEATHER WILL BE AROUND FOR A
FEW DAYS. ON TUESDAY...HIGHS WILL RANGE FROM THE MID 30S IN THE
NORTHWEST TO LOWER 50S IN THE SOUTHEAST. HIGH TEMPERATURES ON
WEDNESDAY WILL ONLY BE IN THE 30S AND LOWER 40S...WITH THE
NORTHWEST STRUGGLING TO REACH ABOVE FREEZING. LOW TEMPERATURES
TUESDAY AND WEDNESDAY NIGHTS WILL BE IN THE 20S AND 30S.
STRENGTHENING WARM AIR ADVECTION WILL ACTUALLY WARM OVERNIGHT
TEMPERATURES WEDNESDAY NIGHT/THURSDAY MORNING BUT LOWS THAT NIGHT
WILL STILL BE IN THE 20S AND 30S...AND HIGHS ON THURSDAY WILL
REMAIN IN THE 30S AND LOWER 40S DUE TO CLOUD COVER AND RAIN.
OUR MAIN CONCERN AND CHALLENGE WITH THIS SYSTEM IS THE POTENTIAL
FOR PRECIPITATION AND ESPECIALLY FROZEN PRECIPITATION. THE UPPER
LEVEL TROUGH WILL CUT OFF INTO A LOW OVER CALIFORNIA ON WEDNESDAY.
WHEN AN UPPER LEVEL LOW CUTS OFF...IT BECOMES SEPARATED FROM THE
MAIN JET STREAM AND WILL TEND TO SLOW DOWN ITS TREK AS A RESULT.
THIS IS INDICATED IN THE MODELS AS THE LOW SLOWS DOWN AND REMAINS
OVER THE SOUTHWESTERN CONUS THROUGH FRIDAY. WITH THE UPPER LEVEL
LOW WELL TO OUR WEST...TEXAS REMAINS IN A NEARLY ZONAL AND/OR
SLIGHTLY RIDGED PATTERN ALOFT. IN THIS PATTERN...THERE IS GENERALLY
A LACK OF LARGE SCALE LIFT ACROSS THE REGION SO WE HAVE TO LOOK
CLOSER AT SMALLER SCALE FEATURES FOR ANY LIFT FOR PRECIPITATION
DEVELOPMENT.
THE FRONT IS EXPECTED TO COME THROUGH DRY AND THE MODELS HAVE
CONSISTENTLY INDICATED NO PRECIPITATION ALONG THE FRONT.
HOWEVER...AS AN H850 HIGH MOVES INTO THE REGION TUESDAY NIGHT AND
WEDNESDAY...IT TURNS THE 850 MB WINDS ACROSS OUR SOUTHWESTERN AND
WESTERN COUNTIES TO THE SOUTH WHICH RESULTS IN SOME WEAK WARM AIR
ADVECTION OVER THE COLD SURFACE LAYER. DO NOT THINK THE WARM AIR
ADVECTION WILL BE STRONG ENOUGH TO GENERATE MUCH PRECIPITATION BUT
THERE IS STILL A SMALL CHANCE IT COULD DEVELOP SOME LIGHT
PRECIPITATION AND WILL RETAIN THE LOW POPS IN THE SOUTHWEST
TUESDAY NIGHT AND IN THE WEST WEDNESDAY WITH A MENTION OF LIGHT
DRIZZLE/FREEZING DRIZZLE. CONFIDENCE IS LOW THIS WILL OCCUR...BUT
IF IT DOES...VERY LIGHT ACCUMULATIONS OF ICE MAY OCCUR ON ELEVATED
SURFACES...WINDSHIELDS...AND POSSIBLY TREE BRANCHES. WE ARE
TRYING TO ANTICIPATE SMALLER SCALE FEATURES SEVERAL DAYS IN
ADVANCE WHICH IS DIFFICULT TO DO...SO WE WANT TO EMPHASIS THAT THE
CHANCES FOR FROZEN PRECIPITATION REMAIN LOW AND WILL CONTINUE TO
MONITOR THIS TIME PERIOD IN FUTURE FORECAST RUNS.
BETTER PRECIPITATION CHANCES ARE EXPECTED THURSDAY THROUGH FRIDAY
AS THE UPPER LEVEL LOW BEGINS MOVING EAST AND INCREASES LIFT
ACROSS THE REGION. WARM AIR ADVECTION AND ISENTROPIC LIFT WILL
START TO INCREASE LATE WEDNESDAY NIGHT AND THURSDAY
MORNING...CONTINUING THROUGH THE DAY ON THURSDAY. IN THIS
REGIME...PRECIPITATION WILL LIKELY DEVELOP FROM SOUTH TO NORTH
ACROSS THE REGION. EVEN THOUGH TEMPERATURES WILL LIKELY BE RISING
FOR PART OF THE NIGHT...THERE WILL STILL BE A PERIOD WHERE
TEMPERATURES WILL BE SLIGHTLY BELOW FREEZING ACROSS OUR WESTERN
COUNTIES AND THESE AREAS COULD SEE LIGHT FREEZING RAIN FOR A FEW
HOURS. IMPACTS SHOULD BE VERY MINIMAL DURING THE PERIOD OF
FREEZING RAIN AS TEMPERATURES ARE EXPECTED TO BE IN THE LOWER 30S
AND FREEZING RAIN USUALLY DOES NOT START TO HAVE A SIGNIFICANT
IMPACT...ESPECIALLY ON ROADS...UNLESS TEMPERATURES ARE IN THE
UPPER 20S. HOWEVER...WE WILL HAVE TO MONITOR CHANGES TO THE
TEMPERATURE FORECAST THAT NIGHT. BUT WITH INCREASING TEMPERATURES
THROUGH THE NIGHT...THE WARMING TEMPERATURES AND CHANGEOVER TO
LIQUID RAIN WILL ACT TO MELT ANY ICE LATER IN THE NIGHT.
A COLD...BUT ALL LIQUID...RAIN IS EXPECTED TO BE MORE WIDESPREAD
THURSDAY THROUGH FRIDAY. HAVE INCREASED POPS IN THIS TIME FRAME
WITH THE MODEL QPF INDICATING SOME BENEFICIAL RAIN IS POSSIBLE.
THERE COULD BE TWO ROUNDS OF RAIN DURING THIS TIME...ONE ON
THURSDAY AND ANOTHER ON FRIDAY. ANOTHER COLD FRONT IS POSSIBLE
FRIDAY OR SATURDAY.
82/JLD
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 42 32 50 33 58 / 40 20 5 5 5
WACO, TX 46 34 49 32 61 / 40 20 10 5 5
PARIS, TX 43 33 49 32 55 / 40 30 5 5 5
DENTON, TX 40 29 50 32 57 / 50 20 5 5 5
MCKINNEY, TX 41 31 49 32 57 / 40 20 5 5 5
DALLAS, TX 43 33 50 34 59 / 40 20 5 5 5
TERRELL, TX 45 34 50 32 58 / 40 30 5 5 5
CORSICANA, TX 47 35 49 33 60 / 40 30 10 5 5
TEMPLE, TX 46 34 49 32 61 / 40 20 20 5 5
MINERAL WELLS, TX 41 28 49 31 58 / 60 10 5 5 5
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 3 PM CST THIS AFTERNOON FOR TXZ091-
100-101-115.
&&
$$
79/05
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1015 AM CST SAT DEC 27 2014
.UPDATE...
MINOR UPDATE TO ADJUST AND CLEAN UP POPS AND CHANCES. A FEW
REPORTS OF WINTRY MIX OF WINTER PRECIPITATION ACROSS WESTERN YOUNG
AND STEPHENS COUNTIES...BUT TEMPERATURES ARE IN THE MID 30S AND
ROADS ARE MOSTLY WET...THOUGH ELEVATED SURFACES HAVE TO BE
WATCHED OUT THAT WAY. DUE TO LIMITED...IF ANY IMPACTS...WE DO NOT
PLAN ON ISSUING ANY ADVISORIES THROUGH TODAY AS THIS SHORTWAVE
LIFTS OUT READILY TO THE NORTHEAST AND TEMPERATURES REMAIN MOSTLY
STEADY STATE. WE WILL BE WATCHING FOR ANY POSSIBLE WET-BULB
EFFECTS HOWEVER TO THE NORTHWEST OF THE DFW METRO.
OTHERWISE...A FEW ELEVATED SHOWERS AND STORMS ABOVE THE FRONTAL
INVERSION ACROSS THE SOUTHEAST COUNTIES THROUGH THIS AFTERNOON.
CAN/T RULE OUT A LITTLE PEA HAIL WITH STRONGEST ACTIVITY. IT WILL
REMAIN MAINLY CLOUDY...WINDY AND COLD THROUGHOUT THE DAY WITH ONLY
A SLOW DROP IN TEMPS WITH CONTINUED CAA.
05/
&&
.AVIATION...
/ISSUED 553 AM CST SAT DEC 27 2014/
A COLD FRONT HAD MOVED THROUGH ALL TAF SITES AS OF 530 AM. THE
PASSAGE OF THE FRONT BROUGHT DRIER AIR AND LIFTING CEILINGS. MVFR
CONDITIONS WILL PREVAIL THROUGH SUNRISE WITH CEILINGS LIFTING
ABOVE 3000 FT BY MID TO LATE MORNING. SCATTERED LIGHT SHOWERS ARE
POSSIBLE THROUGH THE MORNING BUT THE BETTER RAIN CHANCES WILL
ARRIVE THIS AFTERNOON AS LARGE SCALE LIFT ASSOCIATED WITH A
APPROACHING UPPER TROUGH INCREASES. ANY SHOWERS THAT DEVELOP THIS
AFTERNOON WILL BE RELATIVELY LIGHT BUT MAY BE ACCOMPANIED BY MVFR
CEILINGS. A FEW SHOWERS COULD LINGER OVERNIGHT BUT COVERAGE WILL
BE TOO LIMITED TO INCLUDE IN THIS FORECAST. VFR CONDITIONS WILL PREVAIL
TONIGHT WITH SCATTERED TO BROKEN MIDDLE AND UPPER LEVEL CLOUDS.
A NORTH WIND WILL PREVAIL BETWEEN 16 AND 20 KNOTS TODAY WITH SOME
GUSTS UP TO ABOUT 27 KNOTS. WIND SPEEDS SHOULD FALL BELOW 15 KNOTS
BY MID EVENING.
79
&&
.PREV UPDATE...
HAVE UPDATED TO INCLUDE A RAIN/SLEET/SNOW MIX WEST OF A SHERMAN TO
WEATHERFORD TO COMANCHE LINE FOR THE REMAINDER OF THE DAY. RECENT
REPORTS FROM AREAS JUST WEST OF THE CWA INDICATE SOME LIGHT SNOW AND
SLEET IS OCCURRING. FORECAST SOUNDINGS...IN PARTICULAR THE
RAP...SUPPORT SOME LIGHT SNOW AND/OR SLEET MAY OCCUR WITH THE RAIN
TODAY ACROSS THE WEST AND NORTHWEST. VERY LITTLE SNOW OR SLEET
ACCUMULATIONS MAY OCCUR ON ELEVATED OR METAL SURFACES AND ROADWAYS
ARE EXPECTED TO REMAIN CLEAR OF ANY SNOW OR SLEET. ALSO ADJUSTED
POPS UP FOR THE MORNING HOURS BASED ON LATEST RADAR TRENDS. UPDATED
HOURLY TEMPERATURE FORECASTS AND WIND TRENDS FOR THE REMAINDER OF
THE DAY AS WELL USING THE LATEST RAP DATA. THE FRONT HAS JUST
ABOUT PUSHED THROUGH THE ENTIRE CWA AS OF 725 AM.
82/JLD
&&
.PREV DISCUSSION... /ISSUED 442 AM CST SAT DEC 27 2014/
THE FIRST OF THREE COLD FRONTS THAT WILL AFFECT THE REGION OVER
THE NEXT 7-8 DAYS IS CURRENTLY MOVING THROUGH NORTH CENTRAL TEXAS.
AT 320 AM...THE FRONT WAS ROUGHLY ALONG A LINE FROM PARIS TO
DALLAS TO GOLDTHWAITE. AROUND MID MORNING...THE FRONT WILL HAVE
TRAVERSED OUR ENTIRE CWA...MOVING SOUTH AND SOUTHEAST. TEMPERATURES
BEHIND THE FRONT HAVE FALLEN INTO THE 40S WHILE TEMPERATURES AHEAD
OF THE FRONT REMAIN IN THE 60S. MOST LOCATIONS WILL EXPERIENCE
THEIR DAYTIME HIGHS NEAR DAYBREAK WITH SLOWLY FALLING TEMPERATURES
THROUGHOUT THE DAY. HOWEVER...AFTERNOON TEMPERATURES ACROSS OUR
NORTHWESTERN COUNTIES WILL LIKELY REMAIN NEARLY STEADY...POSSIBLY
CREEPING UP A DEGREE OR TWO...BEFORE BEGINNING TO FALL AGAIN AROUND
SUNSET THIS EVENING. THE REGION WILL REMAIN OVERCAST/CLOUDY TODAY
WITH SOME CLEARING ACROSS THE WEST THIS EVENING AND TONIGHT.
HOWEVER...HIGH CLOUDS WILL BEGIN MOVING IN FROM THE WEST WHICH
CREATES A CHALLENGE FOR OVERNIGHT LOWS. THE HIGH CLOUD COVER
SHOULD KEEP OVERNIGHT LOWS FROM FULLY FALLING AS MUCH AS THEY
WOULD UNDER CLEARER SKIES...BUT STILL EXPECT A MUCH COLDER NIGHT
WITH OVERNIGHT LOWS IN THE UPPER 20S NORTHWEST TO UPPER 30S IN THE
SOUTHEAST WHERE DENSE CLOUD COVER WILL PREVAIL.
ONGOING SHOWERS THIS MORNING WILL CONTINUE THROUGH THE DAY AS LIFT
FROM AN UPPER LEVEL TROUGH TO OUR WEST CONTINUES ACROSS THE
REGION. WHILE THERE COULD BE A FEW RUMBLES OF THUNDER AT
TIMES...HAVE LEFT THE THUNDER MENTION OUT OF THE FORECAST FOR NOW
AS THE ELEVATED INSTABILITY IS PRETTY MINIMAL. MOST OF THE AREA
WILL RECEIVE LESS THAN A QUARTER OF AN INCH OF RAIN TODAY...WITH
SOME ISOLATED HIGHER AMOUNTS. MOST THE PRECIPITATION WILL END THIS
EVENING BUT SOME ADDITIONAL SHOWERS MAY OCCUR SUNDAY MORNING
ACROSS OUR SOUTHERN COUNTIES AS THE UPPER LEVEL TROUGH SWINGS
THROUGH THE REGION. WE WILL SEE WARMING TEMPERATURES SUNDAY
THROUGH MONDAY AS WE AWAIT OUR NEXT SYSTEM.
THE NEXT SYSTEM CONTINUES TO BE A DEEPENING TROUGH OVER THE WEST
COAST NEXT WEEK. THIS TROUGH IS CURRENTLY LOCATED OFF THE COAST
OF BRITISH COLUMBIA AND WILL CONTINUE A SOUTHWARD TRACK FOR THE
NEXT SEVERAL DAYS. AS THIS TROUGH DEVELOPS...IT WILL MAINTAIN A
BROAD LATITUDINAL ORIENTATION OR POSITIVE TILT...WHICH RESULTS IN
NEAR ZONAL FLOW ACROSS A GOOD MAJORITY OF THE COUNTRY. THIS
ORIENTATION WILL ALLOW COLD ARCTIC AIR AT THE SURFACE TO RUSH OUT
OF CANADA...INTO THE PLAINS...AND DOWN THROUGH TEXAS. THE ARCTIC
FRONT SHOULD NOT MEET MUCH RESISTANCE MOVING SOUTH AND IS EXPECTED
TO ARRIVE HERE MONDAY NIGHT/TUESDAY MORNING. THE FRONT IS NOT
EXPECTED TO QUICKLY AND AGGRESSIVELY MOVE THROUGH THE REGION...BUT
WILL INSTEAD GRADUALLY SPREAD ACROSS THE REGION WITH NOTICEABLY
COLDER TEMPERATURES BEHIND THE FRONT. THE 1055 MB PLUS SURFACE
HIGH BEHIND THE FRONT WILL TAKE A FEW DAYS TO MOVE INTO THE
SOUTHERN PLAINS...MEANING THE COLD WEATHER WILL BE AROUND FOR A
FEW DAYS. ON TUESDAY...HIGHS WILL RANGE FROM THE MID 30S IN THE
NORTHWEST TO LOWER 50S IN THE SOUTHEAST. HIGH TEMPERATURES ON
WEDNESDAY WILL ONLY BE IN THE 30S AND LOWER 40S...WITH THE
NORTHWEST STRUGGLING TO REACH ABOVE FREEZING. LOW TEMPERATURES
TUESDAY AND WEDNESDAY NIGHTS WILL BE IN THE 20S AND 30S.
STRENGTHENING WARM AIR ADVECTION WILL ACTUALLY WARM OVERNIGHT
TEMPERATURES WEDNESDAY NIGHT/THURSDAY MORNING BUT LOWS THAT NIGHT
WILL STILL BE IN THE 20S AND 30S...AND HIGHS ON THURSDAY WILL
REMAIN IN THE 30S AND LOWER 40S DUE TO CLOUD COVER AND RAIN.
OUR MAIN CONCERN AND CHALLENGE WITH THIS SYSTEM IS THE POTENTIAL
FOR PRECIPITATION AND ESPECIALLY FROZEN PRECIPITATION. THE UPPER
LEVEL TROUGH WILL CUT OFF INTO A LOW OVER CALIFORNIA ON WEDNESDAY.
WHEN AN UPPER LEVEL LOW CUTS OFF...IT BECOMES SEPARATED FROM THE
MAIN JET STREAM AND WILL TEND TO SLOW DOWN ITS TREK AS A RESULT.
THIS IS INDICATED IN THE MODELS AS THE LOW SLOWS DOWN AND REMAINS
OVER THE SOUTHWESTERN CONUS THROUGH FRIDAY. WITH THE UPPER LEVEL
LOW WELL TO OUR WEST...TEXAS REMAINS IN A NEARLY ZONAL AND/OR
SLIGHTLY RIDGED PATTERN ALOFT. IN THIS PATTERN...THERE IS GENERALLY
A LACK OF LARGE SCALE LIFT ACROSS THE REGION SO WE HAVE TO LOOK
CLOSER AT SMALLER SCALE FEATURES FOR ANY LIFT FOR PRECIPITATION
DEVELOPMENT.
THE FRONT IS EXPECTED TO COME THROUGH DRY AND THE MODELS HAVE
CONSISTENTLY INDICATED NO PRECIPITATION ALONG THE FRONT.
HOWEVER...AS AN H850 HIGH MOVES INTO THE REGION TUESDAY NIGHT AND
WEDNESDAY...IT TURNS THE 850 MB WINDS ACROSS OUR SOUTHWESTERN AND
WESTERN COUNTIES TO THE SOUTH WHICH RESULTS IN SOME WEAK WARM AIR
ADVECTION OVER THE COLD SURFACE LAYER. DO NOT THINK THE WARM AIR
ADVECTION WILL BE STRONG ENOUGH TO GENERATE MUCH PRECIPITATION BUT
THERE IS STILL A SMALL CHANCE IT COULD DEVELOP SOME LIGHT
PRECIPITATION AND WILL RETAIN THE LOW POPS IN THE SOUTHWEST
TUESDAY NIGHT AND IN THE WEST WEDNESDAY WITH A MENTION OF LIGHT
DRIZZLE/FREEZING DRIZZLE. CONFIDENCE IS LOW THIS WILL OCCUR...BUT
IF IT DOES...VERY LIGHT ACCUMULATIONS OF ICE MAY OCCUR ON ELEVATED
SURFACES...WINDSHIELDS...AND POSSIBLY TREE BRANCHES. WE ARE
TRYING TO ANTICIPATE SMALLER SCALE FEATURES SEVERAL DAYS IN
ADVANCE WHICH IS DIFFICULT TO DO...SO WE WANT TO EMPHASIS THAT THE
CHANCES FOR FROZEN PRECIPITATION REMAIN LOW AND WILL CONTINUE TO
MONITOR THIS TIME PERIOD IN FUTURE FORECAST RUNS.
BETTER PRECIPITATION CHANCES ARE EXPECTED THURSDAY THROUGH FRIDAY
AS THE UPPER LEVEL LOW BEGINS MOVING EAST AND INCREASES LIFT
ACROSS THE REGION. WARM AIR ADVECTION AND ISENTROPIC LIFT WILL
START TO INCREASE LATE WEDNESDAY NIGHT AND THURSDAY
MORNING...CONTINUING THROUGH THE DAY ON THURSDAY. IN THIS
REGIME...PRECIPITATION WILL LIKELY DEVELOP FROM SOUTH TO NORTH
ACROSS THE REGION. EVEN THOUGH TEMPERATURES WILL LIKELY BE RISING
FOR PART OF THE NIGHT...THERE WILL STILL BE A PERIOD WHERE
TEMPERATURES WILL BE SLIGHTLY BELOW FREEZING ACROSS OUR WESTERN
COUNTIES AND THESE AREAS COULD SEE LIGHT FREEZING RAIN FOR A FEW
HOURS. IMPACTS SHOULD BE VERY MINIMAL DURING THE PERIOD OF
FREEZING RAIN AS TEMPERATURES ARE EXPECTED TO BE IN THE LOWER 30S
AND FREEZING RAIN USUALLY DOES NOT START TO HAVE A SIGNIFICANT
IMPACT...ESPECIALLY ON ROADS...UNLESS TEMPERATURES ARE IN THE
UPPER 20S. HOWEVER...WE WILL HAVE TO MONITOR CHANGES TO THE
TEMPERATURE FORECAST THAT NIGHT. BUT WITH INCREASING TEMPERATURES
THROUGH THE NIGHT...THE WARMING TEMPERATURES AND CHANGEOVER TO
LIQUID RAIN WILL ACT TO MELT ANY ICE LATER IN THE NIGHT.
A COLD...BUT ALL LIQUID...RAIN IS EXPECTED TO BE MORE WIDESPREAD
THURSDAY THROUGH FRIDAY. HAVE INCREASED POPS IN THIS TIME FRAME
WITH THE MODEL QPF INDICATING SOME BENEFICIAL RAIN IS POSSIBLE.
THERE COULD BE TWO ROUNDS OF RAIN DURING THIS TIME...ONE ON
THURSDAY AND ANOTHER ON FRIDAY. ANOTHER COLD FRONT IS POSSIBLE
FRIDAY OR SATURDAY.
82/JLD
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 43 32 50 33 58 / 60 20 5 5 5
WACO, TX 46 34 49 32 61 / 60 20 10 5 5
PARIS, TX 45 33 49 32 55 / 60 30 5 5 5
DENTON, TX 42 29 50 32 57 / 60 20 5 5 5
MCKINNEY, TX 43 31 49 32 57 / 60 20 5 5 5
DALLAS, TX 43 33 50 34 59 / 60 20 5 5 5
TERRELL, TX 45 34 50 32 58 / 60 30 5 5 5
CORSICANA, TX 47 35 49 33 60 / 60 30 10 5 5
TEMPLE, TX 46 34 49 32 61 / 50 20 20 5 5
MINERAL WELLS, TX 41 28 49 31 58 / 60 10 5 5 5
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
79/05