Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 02/27/15
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
840 PM MST THU FEB 26 2015
.UPDATE...
ISSUED AT 826 PM MST THU FEB 26 2015
WIDESPREAD LIGHT SNOW CONTINUES ACROSS MUCH OF NORTHERN COLORADO
THIS EVENING. THERE IS SOME SLIGHT DIMINISHMENT SOUTH DENVER AND
DOUGLAS COUNTY AS STRONGER SOUTH TO SOUTHEAST LOW LEVEL FLOW
DEVELOPS. PROFILERS/VAD WINDS CONFIRM THIS WITH AS LOW LEVEL FLOW
CONTINUES TO TURN MORE SOUTHEAST. HOWEVER...NORTH AND EAST OF THE
CIRCULATION CENTER HERE CONTINUES TO BE SOME EMBEDDED AREAS OF
MODERATE SNOW MAINLY EAST DENVER AND UP THROUGH AURORA AND DIA.
THE UPPER TROF IS MOVING SLOWLY AND QG FIELDS SUGGESTS STILL SHOW
WEAK UPWARD ASCENT THROUGH MUCH OF THE NIGHT. MAIN TO CHANGE TO
EVENING FORECAST WAS TO DELAY SOME OF THE SNOW DIMINISHMENT
OVERNIGHT. ANY ADDITIONAL SNOWFALL WILL STILL BE LIGHT...MAINLY IN
THE 1-2 INCH RANGE.
UPDATE ISSUED AT 631 PM MST THU FEB 26 2015
LOW LEVEL CIRCULATION SHOWING UP NICE ON RADAR AND OBSERVATIONS
EARLY THIS EVENING OVER SOUTHERN PORTIONS OF DENVER. THERE HAS
BEEN SOME NORTHWARD MOVEMENT OF THE CIRCULATION DURING THE PAST
HOUR AND NOW INTO AURORA. THERE IS SOME MODERATE TO HEAVY BANDS
JUST NORTH OF THE CIRCULATION AROUND DIA AND POINTS TO THE EAST
ACROSS EASTERN ADAMS COUNTY. THE REST OF THE URBAN CORRIDOR
CONTINUES WITH JUST LIGHT SNOW WITH EMBEDDED BANDS OF MODERATE
SNOW. CURRENT FORECAST STILL LOOKS ON TRACK WITH 1-3 INCHES.
LATEST HRRR SEEMS TO HAVE A PRETTY GOOD HANDLE ON THE CIRCULATION
AND THE HEAVIER SNOW BANDS. NO CHANGES AT THIS POINT.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 136 PM MST THU FEB 26 2015
RADAR ECHOES STARTING TO FILL IN AROUND DENVER AS THE NEXT SYSTEM
APPROACHES THE REGION FROM THE NORTHWEST. WEAK UPSLOPE COUPLED
WITH WEAK MID TO UPPER LEVEL QG ASCENT WILL BE IN PLAY THROUGH
THIS EVENING. ADDITIONAL ACCUMULATIONS OF AN INCH OR LESS THROUGH
THE REST OF THE AFTERNOON...WITH ANOTHER 1 TO 3 INCHES THIS
EVENING. BEST ACCUMULATIONS WILL BE IN AND NEAR THE FOOTHILLS AND
PALMER DIVIDE. IN THE HIGH COUNTRY...RIDGETOP WINDS WILL BE MORE
WESTERLY OVERNIGHT. THE MOUNTAINS COULD PICK UP ANOTHER 2 TO 5
INCHES OVERNIGHT. BEST MID LEVEL INSTABILITY TONIGHT WILL BE WEST
OF THE DIVIDE WITH H7/H5 LAPSE RATE 7.5-8C/KM EARLY...SO SNOW
THERE WILL BE MORE CONVECTIVE. EAST OF THE DIVIDE...MORE OF AN
OVERRUNNING SITUATION. WINDS AND SNOW ACCUMULATIONS SHOULD BE
UNDER ADVISORY CRITERIA TONIGHT SO NO HIGHLIGHTS PLANNED AT THIS
TIME. ON FRIDAY...THE SYSTEM SHIFTS TO THE SOUTH AND EAST WITH
DECREASING SNOW COVERAGE THROUGH THE DAY. ACROSS THE NORTHEAST
PLAINS...A FAIRLY DECENT SE TO NW SFC PRESSURE GRADIENT SETS UP
ESPECIALLY TO THE EAST AND SOUTHEAST OF DENVER. AS A
RESULT...THERE COULD BE SOME AREAS OF BLOWING SNOW IN THE
AFTERNOON WITH GUSTS OF 25-35 MPH POSSIBLE. TEMPERATURES WILL
REMAIN COLD WITH WIND CHILL TEMPERATURES FROM 5 TO 10 BELOW ZERO
IN THE WINDIER AREAS...PRIMARILY THE I70 CORRIDOR EAST OF DENVER
TO THE STATELINE.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 136 PM MST THU FEB 26 2015
ON FRIDAY NIGHT...THE JET STREAM WILL BE OVER THE DESERT SOUTHWEST
AND SOUTHERN ROCKIES. THIS IS EXPECTED TO KEEP MOST OF THE SNOW TO
OUR SOUTH...OVER SOUTHERN COLORADO AND NEW MEXICO. AS THE JET STREAM
SHIFTS NORTH LATE FRIDAY NIGHT AND SATURDAY SNOW IS EXPECTED TO MOVE
INTO THE MOUNTAINS OF NORTH CENTRAL COLORADO. WILL KEEP LOW POPS IN
THE FORECAST...MAINLY FOR THE MOUNTAINS FRIDAY NIGHT AND EARLY
SATURDAY. WILL THEN INCREASE POPS AS THE JET MOVES OVER THE AREA
SATURDAY AFTERNOON AND NIGHT. IN ADDITION TO THE JET...LOW LEVEL
WINDS WILL TURN NORTH TO NORTHEAST SATURDAY AND SATURDAY EVENING AND
PRODUCE WEAK UPSLOPE LIFT. NOT A STRONG PUSH LIKE THE PREVIOUS
SYSTEMS...SO JUST EXPECT LIGHT TO OCCASIONAL MODERATE SNOW. BEST
ACCUMULATION SHOULD BE OVER THE MOUNTAINS.
FOR SUNDAY AND MONDAY...SOUTHWEST FLOW WILL PREVAIL AS A BROAD UPPER
LEVEL TROUGH REMAINS OVER THE SOUTHWEST PART OF THE COUNTRY. BEST
CHANCE FOR SNOW UNDER THIS PATTERN WILL BE OVER THE MOUNTAINS. WILL
KEEP LOW POPS IN THE FORECAST FOR THE AREA...MAINLY FOR THE CHANCE
OF LIGHT SNOW.
THERE WILL BE A BETTER CHANCE FOR SNOW TUESDAY AND WEDNESDAY AS
ANOTHER SYSTEM DROPS SOUTHEAST ACROSS THE AREA. IF THIS PANS OUT...
THIS WILL PUSH A COLD FRONT THROUGH THE AREA AND BRING A PERIOD OF
SNOW. TIMING IS STILL UNCERTAIN THIS FAR OUT...BUT STILL LOOKING
LIKE A PERIOD OF SNOW FOR MUCH OF THE AREA.
ON THURSDAY...UPPER LEVEL RIDGE WILL BUILD OVER THE GREAT BASIN AND
PRODUCE A NORTHWEST FLOW OVER COLORADO. IT WILL BE DRY...BUT STILL
COOL UNDER THIS PATTERN.&&
.AVIATION...(FOR THE TAFS THROUGH 00Z FRIDAY LATE AFTERNOON)
ISSUED AT 136 PM MST THU FEB 26 2015
PREVAILING MVFR/IFR CIG/VSBY RESTRICTIONS THROUGH 06Z
TONIGHT...LINGERING A BIT LONGER AT KBJC AND KAPA. CONDITIONS
DETERIORATING ALREADY THIS AFTERNOON WITH PREVAILING VSBYS LESS
OF A MILE LIKELY AFTER 00Z THIS EVENING. SNOW COVERAGE WILL
DECREASE OVERNIGHT. SFC WINDS PRIMARILY E/SELY. SOME STRONGER
GUSTS POSSIBLE AT KDEN FRIDAY AFTN...SO AREAS OF BLSN MAY ALSO BE
AN ISSUE AFTER 18Z IF SOME STRONGER GUSTS 20-25 KTS DVLP.
&&
.AVIATION...(FOR THE TAFS THROUGH 06Z FRIDAY EVENING)
ISSUED AT 826 PM MST THU FEB 26 2015
CEILINGS/VSBYS CONTINUE TO VERY SLOWLY IMPROVE AT APA/DEN AS MORE
SOUTH TO SOUTHEAST FLOW DEVELOPS. IN FACT ALREADY SEEING SOUTHWEST
WINDS AT APA. LOWER CIGS AND BJC WITH CONTINUED NORTH TO NORTHEAST
LOW LEVEL FLOW. MAIN CHANGE TO UPCOMING TAFS WILL BE TO KEEP THE
LIGHT SNOW IN THE TERMINALS A BIT LONGER THAN CURRENT AS SNOW
APPEARS TO BE SLOW TO END FROM THE NORTH. ADDITIONAL SNOWFALL WILL
BE AROUND AN INCH OR LESS...HIGHEST AT BJC AND LOWER AT APA.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...ENTREKIN
SHORT TERM...COOPER
LONG TERM...MEIER
AVIATION...ENTREKIN
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
647 PM MST THU FEB 26 2015
.UPDATE...
ISSUED AT 631 PM MST THU FEB 26 2015
LOW LEVEL CIRCULATION SHOWING UP NICE ON RADAR AND OBSERVATIONS
EARLY THIS EVENING OVER SOUTHERN PORTIONS OF DENVER. THERE HAS
BEEN SOME NORTHWARD MOVEMENT OF THE CIRCULATION DURING THE PAST
HOUR AND NOW INTO AURORA. THERE IS SOME MODERATE TO HEAVY BANDS
JUST NORTH OF THE CIRCULATION AROUND DIA AND POINTS TO THE EAST
ACROSS EASTERN ADAMS COUNTY. THE REST OF THE URBAN CORRIDOR
CONTINUES WITH JUST LIGHT SNOW WITH EMBEDDED BANDS OF MODERATE
SNOW. CURRENT FORECAST STILL LOOKS ON TRACK WITH 1-3 INCHES.
LATEST HRRR SEEMS TO HAVE A PRETTY GOOD HANDLE ON THE CIRCULATION
AND THE HEAVIER SNOW BANDS. NO CHANGES AT THIS POINT.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 136 PM MST THU FEB 26 2015
RADAR ECHOES STARTING TO FILL IN AROUND DENVER AS THE NEXT SYSTEM
APPROACHES THE REGION FROM THE NORTHWEST. WEAK UPSLOPE COUPLED
WITH WEAK MID TO UPPER LEVEL QG ASCENT WILL BE IN PLAY THROUGH
THIS EVENING. ADDITIONAL ACCUMULATIONS OF AN INCH OR LESS THROUGH
THE REST OF THE AFTERNOON...WITH ANOTHER 1 TO 3 INCHES THIS
EVENING. BEST ACCUMULATIONS WILL BE IN AND NEAR THE FOOTHILLS AND
PALMER DIVIDE. IN THE HIGH COUNTRY...RIDGETOP WINDS WILL BE MORE
WESTERLY OVERNIGHT. THE MOUNTAINS COULD PICK UP ANOTHER 2 TO 5
INCHES OVERNIGHT. BEST MID LEVEL INSTABILITY TONIGHT WILL BE WEST
OF THE DIVIDE WITH H7/H5 LAPSE RATE 7.5-8C/KM EARLY...SO SNOW
THERE WILL BE MORE CONVECTIVE. EAST OF THE DIVIDE...MORE OF AN
OVERRUNNING SITUATION. WINDS AND SNOW ACCUMULATIONS SHOULD BE
UNDER ADVISORY CRITERIA TONIGHT SO NO HIGHLIGHTS PLANNED AT THIS
TIME. ON FRIDAY...THE SYSTEM SHIFTS TO THE SOUTH AND EAST WITH
DECREASING SNOW COVERAGE THROUGH THE DAY. ACROSS THE NORTHEAST
PLAINS...A FAIRLY DECENT SE TO NW SFC PRESSURE GRADIENT SETS UP
ESPECIALLY TO THE EAST AND SOUTHEAST OF DENVER. AS A
RESULT...THERE COULD BE SOME AREAS OF BLOWING SNOW IN THE
AFTERNOON WITH GUSTS OF 25-35 MPH POSSIBLE. TEMPERATURES WILL
REMAIN COLD WITH WIND CHILL TEMPERATURES FROM 5 TO 10 BELOW ZERO
IN THE WINDIER AREAS...PRIMARILY THE I70 CORRIDOR EAST OF DENVER
TO THE STATELINE.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 136 PM MST THU FEB 26 2015
ON FRIDAY NIGHT...THE JET STREAM WILL BE OVER THE DESERT SOUTHWEST
AND SOUTHERN ROCKIES. THIS IS EXPECTED TO KEEP MOST OF THE SNOW TO
OUR SOUTH...OVER SOUTHERN COLORADO AND NEW MEXICO. AS THE JET STREAM
SHIFTS NORTH LATE FRIDAY NIGHT AND SATURDAY SNOW IS EXPECTED TO MOVE
INTO THE MOUNTAINS OF NORTH CENTRAL COLORADO. WILL KEEP LOW POPS IN
THE FORECAST...MAINLY FOR THE MOUNTAINS FRIDAY NIGHT AND EARLY
SATURDAY. WILL THEN INCREASE POPS AS THE JET MOVES OVER THE AREA
SATURDAY AFTERNOON AND NIGHT. IN ADDITION TO THE JET...LOW LEVEL
WINDS WILL TURN NORTH TO NORTHEAST SATURDAY AND SATURDAY EVENING AND
PRODUCE WEAK UPSLOPE LIFT. NOT A STRONG PUSH LIKE THE PREVIOUS
SYSTEMS...SO JUST EXPECT LIGHT TO OCCASIONAL MODERATE SNOW. BEST
ACCUMULATION SHOULD BE OVER THE MOUNTAINS.
FOR SUNDAY AND MONDAY...SOUTHWEST FLOW WILL PREVAIL AS A BROAD UPPER
LEVEL TROUGH REMAINS OVER THE SOUTHWEST PART OF THE COUNTRY. BEST
CHANCE FOR SNOW UNDER THIS PATTERN WILL BE OVER THE MOUNTAINS. WILL
KEEP LOW POPS IN THE FORECAST FOR THE AREA...MAINLY FOR THE CHANCE
OF LIGHT SNOW.
THERE WILL BE A BETTER CHANCE FOR SNOW TUESDAY AND WEDNESDAY AS
ANOTHER SYSTEM DROPS SOUTHEAST ACROSS THE AREA. IF THIS PANS OUT...
THIS WILL PUSH A COLD FRONT THROUGH THE AREA AND BRING A PERIOD OF
SNOW. TIMING IS STILL UNCERTAIN THIS FAR OUT...BUT STILL LOOKING
LIKE A PERIOD OF SNOW FOR MUCH OF THE AREA.
ON THURSDAY...UPPER LEVEL RIDGE WILL BUILD OVER THE GREAT BASIN AND
PRODUCE A NORTHWEST FLOW OVER COLORADO. IT WILL BE DRY...BUT STILL
COOL UNDER THIS PATTERN.&&
.AVIATION...(FOR THE TAFS THROUGH 00Z FRIDAY LATE AFTERNOON)
ISSUED AT 136 PM MST THU FEB 26 2015
PREVAILING MVFR/IFR CIG/VSBY RESTRICTIONS THROUGH 06Z
TONIGHT...LINGERING A BIT LONGER AT KBJC AND KAPA. CONDITIONS
DETERIORATING ALREADY THIS AFTERNOON WITH PREVAILING VSBYS LESS
OF A MILE LIKELY AFTER 00Z THIS EVENING. SNOW COVERAGE WILL
DECREASE OVERNIGHT. SFC WINDS PRIMARILY E/SELY. SOME STRONGER
GUSTS POSSIBLE AT KDEN FRIDAY AFTN...SO AREAS OF BLSN MAY ALSO BE
AN ISSUE AFTER 18Z IF SOME STRONGER GUSTS 20-25 KTS DVLP.
&&
.AVIATION...(FOR THE TAFS THROUGH 06Z FRIDAY EVENING)
ISSUED AT 631 PM MST THU FEB 26 2015
HEAVIER SNOW AT APA HAS DECREASED AS CIRCULATION SHIFTS NORTH OF
APA. STILL LOOKING AT MODERATE/HEAVY SNOW AT KDEN THROUGH 03Z AS
BANDS OF MODERATE SNOW MOVE IN FROM THE EAST AND SOUTHEAST. THERE
WILL BE AN OVERALL DECREASING TREND IN THE SNOW BY LATER THIS
EVENING. SNOWFALL ACCUMULATIONS 1-2 INCHES WITH LOCAL UP TO 3
INCHES IN THE HEAVIER BANDS OF SNOW.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...ENTREKIN
SHORT TERM...COOPER
LONG TERM...MEIER
AVIATION...ENTREKIN
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
957 AM MST WED FEB 25 2015
.UPDATE...
ISSUED AT 945 AM MST WED FEB 25 2015
STRONG NORTHEAST WINDS ALREADY HAVE MOVED INTO DENVER A SHORT TIME
AGO SO HAVE SPED UP THE TIMING BY 2-3 HOURS REGARDING THE ONSET OF
PRECIPITATION. HIGHS LIKELY HAVE BEEN MET OR WILL BE MET SHORTLY
THEN SHOULD SEE THEM DROP INTO THE 30S THIS AFTERNOON. STILL SOME
QUESTION REGARDING THE AMOUNT OF SNOW FOR DENVER...THE ADVISORY
MAY NEED TO BE UPGRADED CLOSER TO THE FOOTHILLS AND PALMER DIVIDE
BUT STILL NOT SURE AT THIS TIME...WL SEE HOW THINGS DEVELOP THIS
AFTERNOON.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT )
ISSUED AT 424 AM MST WED FEB 25 2015
A STREAK OF DIFFICULT FORECASTS REMAINS IN TACT. A LOT GOING ON
THIS AFTERNOON AND EVENING...AND AGAIN POTENTIAL OF CONVECTION
THROWS A LOT OF VARIABILITY INTO MODEL OUTPUT AND FORECAST
CONFIDENCE FOR SNOWFALL AMOUNTS IN ANY PARTICULAR AREA.
HERE IS WHERE WE ARE...LIGHT SNOW IS OCCURRING IN THE MOUNTAINS
EARLY THIS MORNING BUT THIS SHOULD DECREASE AS SOME DRIER AIR
ALOFT WORKS ACROSS THE AREA THIS MORNING. ON THE PLAINS...WE
SHOULD SEE A FEW RAIN/SNOW SHOWERS SPREADING SOUTHEAST EARLY THIS
MORNING...MAINLY EAST OF A GREELEY TO LIMON LINE. CANT EVEN RULE
OUT A BIT OF FREEZING VERY LIGHT RAIN/SPRINKLES AS A FEW VALLEY
LOCATIONS MAY HOVER JUST BELOW FREEZING AS LIGHT PRECIP BEGINS.
CLOSER TO THE FRONT RANGE...OCCASIONAL GUSTY CHINOOK WINDS BUT
WARM TEMPERATURES WILL REMAIN IN PLACE...AND ENOUGH DOWNSLOPE TO
HAVE SOME BREAKS IN THE CLOUDS.
MAIN FORECAST ATTENTION TURNS TOWARD STRONG COLD FRONT ACROSS THE
PLAINS...WHICH IS ON TIME TO PUSH THROUGH BETWEEN 1 AND 3 PM.
TEMPERATURES WILL DROP BEHIND THE FRONT WITH ANTICYCLONIC UPSLOPE
DEEPENING. UPSTREAM MOISTURE SEEMS PLENTIFUL BASED ON REAL OBS AND
PRECIPITATION OCCURRING TO OUR NORTH. LAPSE RATES BECOME MORE
UNSTABLE...ESPECIALLY IN THE NAM WHERE SOME CAPE IS
INDICATED...WHILE GFS IS SLIGHTLY MORE STABLE. THE NAM...AS WELL
AS SEVERAL MESOSCALE MODELS INCLUDING THE NMM...ARW...AND THE
FINAL HOURS OF THE RAP AND HRRR INDICATE CONVECTION BLOSSOMING
WITH 2 INCH PER HOUR SNOW RATES. BUT THEY ALSO CONFINE THEM TO
AREAS VERY CLOSE TO THE FOOTHILLS...WHICH SEEMS POSSIBLE
CONSIDERING THE STRENGTH OF NORTH/NORTHEAST FLOW. IF THIS VERIFIES
THEN HEAVIER SNOW WOULD CERTAINLY BE MORE FOCUSED TOWARD THE
FOOTHILLS...AND MUCH LESS POTENTIAL FOR MUCH ACCUMULATION TOWARD
FORT COLLINS...GREELEY...AND POINTS JUST EAST OF DENVER. WE HAVE
TRENDED FORECASTS IN THIS DIRECTION SINCE THE STRONGER NORTHERLY
FLOW USUALLY SHUTS THOSE AREAS DOWN PRETTY QUICKLY...AND DRIER LOW
LEVEL AIR WITH COLDER ARCTIC AIR THIS EVENING WOULD HAVE A
TENDENCY TO DO THE SAME.
AT THE SAME TIME...THAT ALSO FOCUSES THE HEAVIER PRECIPITATION
TOWARD THE FOOTHILLS SO HAVE OPTED TO ISSUE WINTER STORM WARNINGS
FOR FOOTHILL LOCATIONS...MAINLY BOULDER COUNTY FOOTHILLS SOUTHWARD
TO JEFFERSON/DOUGLAS COUNTIES. THE SOUTHERN FOOTHILLS HAVE NOT
BEEN DOING VERY WELL WITH REGARD TO SNOW AMOUNTS IN THE PAST
COUPLE STORMS BUT GIVEN THE STRONGER FLOW LATER TODAY WE DO EXPECT
HEAVIER TOTALS THERE. ANOTHER CONCERNING AREA IF CONVECTION
BLOSSOMS AS MESOSCALE MODELS INDICATE WOULD BE THE WESTERN SUBURBS
FOR POTENTIAL WARNING CRITERIA. HARD TO EXACTLY SAY HOW THIS COMES
TOGETHER BUT FOR NOW WILL ISSUE ADVISORIES STARTING AROUND 3 PM
FOR THE DENVER/BOULDER METRO AREA AND PALMER DIVIDE. FORT COLLINS
PER DISCUSSION ABOVE SEEMS TO GET EXCLUDED FROM HEAVIER
PRECIPITATION AGAIN. SOME THREAT WESTERN SUBURBS COULD GET A QUICK
6 INCHES PLUS LATE THIS AFTERNOON/EVENING SO WILL MONITOR FOR
POTENTIAL UPGRADE TO WARNING. OVERALL...THERE WILL BE A VERY LARGE
DISPARITY WITH SNOW TOTALS WITH LITERALLY TRACE TO 10 INCH AMOUNTS
POSSIBLE IN PORTIONS OF THE DENVER METRO AREA...AND HARD TO
PINPOINT WHO GETS EXACTLY HOW MUCH. ONCE SNOW DEVELOPS WE DO
ANTICIPATE RAPID DETERIORATION OF CONDITIONS AS SNOW INTENSITY
COULD TURN DRY AND WARM ROADS INTO A QUICK SHEET OF PACKED
SNOW/ICE. THE LATE AFTERNOON/EVENING COMMUTE FOR THE
DENVER/BOULDER/PALMER DIVIDE/FOOTHILLS AREAS LOOKS DIFFICULT AT
THIS POINT.
FOR OVERNIGHT...SNOW INTENSITY IS EXPECTED TO GRADUALLY DECREASE
WITH UPSLOPE COMPONENT WEAKENING AND AIRMASS STABILIZING WITH
COLDER/DRIER BOUNDARY LAYER FLOW. MOST OF THE ACCUMULATING SNOW
SHOULD BE OVER BY DAYBREAK SO WILL RUN WARNINGS AND ADVISORIES TIL
6 AM.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 424 AM MST WED FEB 25 2015
THE MEDIUM RANGE MODELS CONTINUE TO INDICATE THAT THIS EVENINGS
SNOWFALL IS THE BEGINNING OF A PROLONGED PERIOD OF LIGHT SNOW
ACROSS MUCH OF THE FORECAST AREA...ESPECIALLY THE MOUNTAINS. THE
FLOW PATTERN ALOFT IS FORECAST TO BEGIN AS A CYCLONICALLY CURVED
NORTHWESTERLY FLOW WITH A COUPLE EMBEDDED SHORT WAVE TROUGHS. BY
FRIDAY EVENING...FLOW ALOFT ACROSS COLORADO WILL BECOME MORE
WESTERLY AS AN UPPER TROUGH BEGINS CARVING OUT OVER THE PACIFIC
NORTHWEST AND THEN GREAT BASIN. THE WESTERLY FLOW WILL BE MOIST
WITH ENOUGH CYCLONIC CURVATURE TO MAINTAIN WEAK QUASI-GEOSTROPHIC
FORCING FOR ASCENT ACROSS THE STATE. THIS WILL RESULT IN A
CONTINUATION OF LIGHT SNOWFALL THROUGH FRIDAY AND SATURDAY. AT
LOWER LEVELS...A VERY COLD AIRMASS WILL MOVE INTO THE REGION
BEHIND THIS AFTERNOONS COLD FRONT AND TAKE UP RESIDENCE OVER
NORTHEAST COLORADO THROUGH ABOUT SUNDAY. A LARGE SURFACE HIGH
OVER THE CENTRAL PLAINS WILL MAINTAIN SOUTHEASTERLY LOW LEVEL FLOW
ACROSS EASTERN COLORADO WELL INTO THE WEEKEND. THIS SHOULD
CONTINUE FEEDING MOISTURE INTO THE REGION WHICH COULD BE HELD
AGAINST THE FOOTHILLS BY A DENVER CYCLONE THAT WILL DEVELOP
THURSDAY NIGHT AND LAST THROUGH SATURDAY. WITH WEAK DYNAMICS
REMAINING OVERHEAD AND MOIST AIR AT LOWER LEVELS...LIGHT SNOW WILL
BE POSSIBLE WHILE THE UPPER FLOW PATTERN REMAINS IN PLACE.
BY LATE IN THE WEEKEND...THE UPPER TROUGH WILL SINK TO THE DESERT
SOUTHWEST...LEAVING COLORADO UNDER THE DEFORMATION ZONE DOWNSTREAM
OF THE UPPER CIRCULATION. THIS WILL PRODUCE THE HEAVIEST SNOWFALL
MORE OVER SOUTHWESTERN COLORADO...SIMILAR TO WHAT OCCURRED THIS
PAST MONDAY. BUT THE NORTH-CENTRAL COLORADO MOUNTAINS WILL BE ON
THE NORTHERN FRINGES OF THIS SYSTEM AND SHOULD RECEIVE AT LEAST
LIGHT SNOWFALL. NO FORECAST PERIOD IS EXPECTED TO CONTAIN
PARTICULARLY HEAVY SNOWFALL AMOUNTS...BUT SEVERAL CONSECUTIVE
PERIODS WITH 2 TO 4 INCHES OF NEW SNOW COULD ADD UP AFTER AWHILE.
TEMPERATURE-WISE...THE COLDEST TEMPERATURES FOR NORTHEAST COLORADO
WILL BE THURSDAY AND FRIDAY WITH ONLY SLIGHT MODERATION THROUGH
THE WEEKEND. DURING THE FIRST HALF OF NEXT WEEK...THE GFS AND
ECMWF HAVE SLIGHTLY DIFFERENT SCENARIOS INVOLVING THE WESTERN U.S.
TROUGH MOVING ACROSS COLORADO. THIS WILL KEEP THE RATHER UNSETTLED
WEATHER OVER THE STATE THROUGH THAT TIME. LITTLE WARMING CAN BE
EXPECTED UNTIL AFTER THE MAIN TROUGH CLEARS THE AREA. ALL IN
ALL...SNOWPACK CONDITIONS WILL ONLY IMPROVE THROUGH THE NEXT WEEK.
&&
.AVIATION...(FOR THE TAFS THROUGH 18Z THURSDAY MORNING)
ISSUED AT 945 AM MST WED FEB 25 2015
STRONG NORTHEAST WINDS ASSOCIATED WITH THE COLD FRONT ALREADY AT
KDEN AND WILL BE AT KBJC AND KAPA. TIMING FOR THE ONSET OF PCPN
WILL LIKELY MOVE UP AS WELL.
VFR CONDITIONS THROUGH 18Z. WINDS NORTHEAST...WITH GUSTS AROUND
25 KNOTS EXPECTED. EXPECT ILS RESTRICTIONS BY 19Z WITH SOME MVFR
CIG/VSBY RESTRICTIONS IN THE DEVELOPING SNOW SHOWERS. IFR
CONDITIONS AND HEAVIER SNOW SHOWERS DEVELOPING 19Z-22Z WITH
POTENTIAL FOR 1-2 INCH PER HOUR SNOW RATES AND TEMPO 1/4SM
VISIBILITY 22Z-02Z. HIGHEST THREAT WOULD BE AT KBJC AND KAPA...BUT
SOME THREAT AT KDEN TOO. OVERALL INTENSITY SHOULD DECREASE AFTER
04Z BUT IFR CONDITIONS WILL LIKELY LINGER WITH LIGHT SNOW THROUGH
EARLY THURSDAY MORNING.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 6 AM MST
THURSDAY FOR COZ039>041.
WINTER STORM WARNING FROM 2 PM THIS AFTERNOON TO 6 AM MST
THURSDAY FOR COZ035-036.
WINTER WEATHER ADVISORY FROM 2 PM THIS AFTERNOON TO 6 AM MST
THURSDAY FOR COZ033-034.
&&
$$
UPDATE...COOPER
SHORT TERM...BARJENBRUCH
LONG TERM...DANKERS
AVIATION...COOPER
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
424 AM MST WED FEB 25 2015
.SHORT TERM...(TODAY THROUGH TONIGHT )
ISSUED AT 424 AM MST WED FEB 25 2015
A STREAK OF DIFFICULT FORECASTS REMAINS IN TACT. A LOT GOING ON
THIS AFTERNOON AND EVENING...AND AGAIN POTENTIAL OF CONVECTION
THROWS A LOT OF VARIABILITY INTO MODEL OUTPUT AND FORECAST
CONFIDENCE FOR SNOWFALL AMOUNTS IN ANY PARTICULAR AREA.
HERE IS WHERE WE ARE...LIGHT SNOW IS OCCURRING IN THE MOUNTAINS
EARLY THIS MORNING BUT THIS SHOULD DECREASE AS SOME DRIER AIR
ALOFT WORKS ACROSS THE AREA THIS MORNING. ON THE PLAINS...WE
SHOULD SEE A FEW RAIN/SNOW SHOWERS SPREADING SOUTHEAST EARLY THIS
MORNING...MAINLY EAST OF A GREELEY TO LIMON LINE. CANT EVEN RULE
OUT A BIT OF FREEZING VERY LIGHT RAIN/SPRINKLES AS A FEW VALLEY
LOCATIONS MAY HOVER JUST BELOW FREEZING AS LIGHT PRECIP BEGINS.
CLOSER TO THE FRONT RANGE...OCCASIONAL GUSTY CHINOOK WINDS BUT
WARM TEMPERATURES WILL REMAIN IN PLACE...AND ENOUGH DOWNSLOPE TO
HAVE SOME BREAKS IN THE CLOUDS.
MAIN FORECAST ATTENTION TURNS TOWARD STRONG COLD FRONT ACROSS THE
PLAINS...WHICH IS ON TIME TO PUSH THROUGH BETWEEN 1 AND 3 PM.
TEMPERATURES WILL DROP BEHIND THE FRONT WITH ANTICYCLONIC UPSLOPE
DEEPENING. UPSTREAM MOISTURE SEEMS PLENTIFUL BASED ON REAL OBS AND
PRECIPITATION OCCURRING TO OUR NORTH. LAPSE RATES BECOME MORE
UNSTABLE...ESPECIALLY IN THE NAM WHERE SOME CAPE IS
INDICATED...WHILE GFS IS SLIGHTLY MORE STABLE. THE NAM...AS WELL
AS SEVERAL MESOSCALE MODELS INCLUDING THE NMM...ARW...AND THE
FINAL HOURS OF THE RAP AND HRRR INDICATE CONVECTION BLOSSOMING
WITH 2 INCH PER HOUR SNOW RATES. BUT THEY ALSO CONFINE THEM TO
AREAS VERY CLOSE TO THE FOOTHILLS...WHICH SEEMS POSSIBLE
CONSIDERING THE STRENGTH OF NORTH/NORTHEAST FLOW. IF THIS VERIFIES
THEN HEAVIER SNOW WOULD CERTAINLY BE MORE FOCUSED TOWARD THE
FOOTHILLS...AND MUCH LESS POTENTIAL FOR MUCH ACCUMULATION TOWARD
FORT COLLINS...GREELEY...AND POINTS JUST EAST OF DENVER. WE HAVE
TRENDED FORECASTS IN THIS DIRECTION SINCE THE STRONGER NORTHERLY
FLOW USUALLY SHUTS THOSE AREAS DOWN PRETTY QUICKLY...AND DRIER LOW
LEVEL AIR WITH COLDER ARCTIC AIR THIS EVENING WOULD HAVE A
TENDENCY TO DO THE SAME.
AT THE SAME TIME...THAT ALSO FOCUSES THE HEAVIER PRECIPITATION
TOWARD THE FOOTHILLS SO HAVE OPTED TO ISSUE WINTER STORM WARNINGS
FOR FOOTHILL LOCATIONS...MAINLY BOULDER COUNTY FOOTHILLS SOUTHWARD
TO JEFFERSON/DOUGLAS COUNTIES. THE SOUTHERN FOOTHILLS HAVE NOT
BEEN DOING VERY WELL WITH REGARD TO SNOW AMOUNTS IN THE PAST
COUPLE STORMS BUT GIVEN THE STRONGER FLOW LATER TODAY WE DO EXPECT
HEAVIER TOTALS THERE. ANOTHER CONCERNING AREA IF CONVECTION
BLOSSOMS AS MESOSCALE MODELS INDICATE WOULD BE THE WESTERN SUBURBS
FOR POTENTIAL WARNING CRITERIA. HARD TO EXACTLY SAY HOW THIS COMES
TOGETHER BUT FOR NOW WILL ISSUE ADVISORIES STARTING AROUND 3 PM
FOR THE DENVER/BOULDER METRO AREA AND PALMER DIVIDE. FORT COLLINS
PER DISCUSSION ABOVE SEEMS TO GET EXCLUDED FROM HEAVIER
PRECIPITATION AGAIN. SOME THREAT WESTERN SUBURBS COULD GET A QUICK
6 INCHES PLUS LATE THIS AFTERNOON/EVENING SO WILL MONITOR FOR
POTENTIAL UPGRADE TO WARNING. OVERALL...THERE WILL BE A VERY LARGE
DISPARITY WITH SNOW TOTALS WITH LITERALLY TRACE TO 10 INCH AMOUNTS
POSSIBLE IN PORTIONS OF THE DENVER METRO AREA...AND HARD TO
PINPOINT WHO GETS EXACTLY HOW MUCH. ONCE SNOW DEVELOPS WE DO
ANTICIPATE RAPID DETERIORATION OF CONDITIONS AS SNOW INTENSITY
COULD TURN DRY AND WARM ROADS INTO A QUICK SHEET OF PACKED
SNOW/ICE. THE LATE AFTERNOON/EVENING COMMUTE FOR THE
DENVER/BOULDER/PALMER DIVIDE/FOOTHILLS AREAS LOOKS DIFFICULT AT
THIS POINT.
FOR OVERNIGHT...SNOW INTENSITY IS EXPECTED TO GRADUALLY DECREASE
WITH UPSLOPE COMPONENT WEAKENING AND AIRMASS STABILIZING WITH
COLDER/DRIER BOUNDARY LAYER FLOW. MOST OF THE ACCUMULATING SNOW
SHOULD BE OVER BY DAYBREAK SO WILL RUN WARNINGS AND ADVISORIES TIL
6 AM.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 424 AM MST WED FEB 25 2015
THE MEDIUM RANGE MODELS CONTINUE TO INDICATE THAT THIS EVENINGS
SNOWFALL IS THE BEGINNING OF A PROLONGED PERIOD OF LIGHT SNOW
ACROSS MUCH OF THE FORECAST AREA...ESPECIALLY THE MOUNTAINS. THE
FLOW PATTERN ALOFT IS FORECAST TO BEGIN AS A CYCLONICALLY CURVED
NORTHWESTERLY FLOW WITH A COUPLE EMBEDDED SHORT WAVE TROUGHS. BY
FRIDAY EVENING...FLOW ALOFT ACROSS COLORADO WILL BECOME MORE
WESTERLY AS AN UPPER TROUGH BEGINS CARVING OUT OVER THE PACIFIC
NORTHWEST AND THEN GREAT BASIN. THE WESTERLY FLOW WILL BE MOIST
WITH ENOUGH CYCLONIC CURVATURE TO MAINTAIN WEAK QUASI-GEOSTROPHIC
FORCING FOR ASCENT ACROSS THE STATE. THIS WILL RESULT IN A
CONTINUATION OF LIGHT SNOWFALL THROUGH FRIDAY AND SATURDAY. AT
LOWER LEVELS...A VERY COLD AIRMASS WILL MOVE INTO THE REGION
BEHIND THIS AFTERNOONS COLD FRONT AND TAKE UP RESIDENCE OVER
NORTHEAST COLROADO THROUGH ABOUT SUNDAY. A LARGE SURFACE HIGH OVER
THE CENTRAL PLAINS WILL MAINTAIN SOUTHEASTERLY LOW LEVEL FLOW
ACROSS EASTERN COLORADO WELL INTO THE WEEKEND. THIS SHOULD
CONTINUE FEEDING MOISTURE INTO THE REGION WHICH COULD BE HELD
AGAINST THE FOOTHILLS BY A DENVER CYCLONE THAT WILL DEVELOP
THURSDAY NIGHT AND LAST THROUGH SATURDAY. WITH WEAK DYNAMICS
REMAINING OVERHEAD AND MOIST AIR AT LOWER LEVELS...LIGHT SNOW WILL
BE POSSIBLE WHILE THE UPPER FLOW PATTERN REMAINS IN PLACE.
BY LATE IN THE WEEKEND...THE UPPER TROUGH WILL SINK TO THE DESERT
SOUTHWEST...LEAVING COLORADO UNDER THE DEFORMATION ZONE DOWNSTREAM
OF THE UPPER CIRCULATION. THIS WILL PRODUCE THE HEAVIEST SNOWFALL
MORE OVER SOUTHWESTERN COLORADO...SIMILAR TO WHAT OCCURRED THIS
PAST MONDAY. BUT THE NORTH-CENTRAL COLORADO MOUNTAINS WILL BE ON
THE NORTHERN FRINGES OF THIS SYSTEM AND SHOULD RECEIVE AT LEAST
LIGHT SNOWFALL. NO FORECAST PERIOD IS EXPECTED TO CONTAIN
PARTICULARLY HEAVY SNOWFALL AMOUNTS...BUT SEVERAL CONSECUTIVE
PERIODS WITH 2 TO 4 INCHES OF NEW SNOW COULD ADD UP AFTER AWHILE.
TEMPERATURE-WISE...THE COLDEST TEMPERATURES FOR NORTHEAST COLORADO
WILL BE THURSDAY AND FRIDAY WITH ONLY SLIGHT MODERATION THROUGH
THE WEEKEND. DURING THE FIRST HALF OF NEXT WEEK...THE GFS AND
ECMWF HAVE SLIGHTLY DIFFERENT SCENARIOS INVOLVING THE WESTERN U.S.
TROUGH MOVING ACROSS COLORADO. THIS WILL KEEP THE RATHER UNSETTLED
WEATHER OVER THE STATE THROUGH THAT TIME. LITTLE WARMING CAN BE
EXPECTED UNTIL AFTER THE MAIN TROUGH CLEARS THE AREA. ALL IN
ALL...SNOWPACK CONDITIONS WILL ONLY IMPROVE THROUGH THE NEXT WEEK.
&&
.AVIATION...(FOR THE TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 424 AM MST WED FEB 25 2015
VFR CONDITIONS WILL PREVAIL THROUGH ABOUT 20Z. WINDS SHOULD TREND
FROM WEST/SOUTHWEST TO NORTHWEST/NORTHERLY THROUGH 18Z...AND THEN
BECOME GUSTY FROM THE NORTH/NORTHEAST WITH FRONTAL PASSAGE 20Z-
21Z WITH GUSTS AROUND 25 KNOTS EXPECTED. EXPECT IFR CONDITIONS AND
HEAVIER SNOW SHOWERS DEVELOPING 21Z-23Z WITH POTENTIAL FOR 1-2
INCH PER HOUR SNOW RATES AND TEMPO 1/4SM VISIBILITY 23Z-04Z.
HIGHEST THREAT WOULD BE AT KBJC AND KAPA...BUT SOME THREAT AT KDEN
TOO. OVERALL INTENSITY SHOULD DECREASE AFTER 04Z BUT IFR
CONDITIONS WILL LIKELY LINGER WITH LIGHT SNOW THROUGH EARLY
THURSDAY MORNING.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 6 AM MST
THURSDAY FOR COZ039>041.
WINTER STORM WARNING FROM 2 PM THIS AFTERNOON TO 6 AM MST
THURSDAY FOR COZ035-036.
WINTER WEATHER ADVISORY FROM 2 PM THIS AFTERNOON TO 6 AM MST
THURSDAY FOR COZ033-034.
&&
$$
SHORT TERM...BARJENBRUCH
LONG TERM...DANKERS
AVIATION...BARJENBRUCH
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
915 PM EST THU FEB 26 2015
.DISCUSSION...
CURRENT-OVERNIGHT...FRONT SLOWLY WORKING ITS WAY DOWN EAST CENTRAL
FLORIDA PER METARS/OBSERVATIONS. PATRICK AFB AND MELBOURNE WERE THE
LATEST TO EXPERIENCE A WIND SHIFT TO THE NORTH AND NORTHEAST AS THE
FRONT MOVED THROUGH. RADARS INDICATING A PERSISTENT STREAM OF
SHOWERS OVER THE SOUTHERN 4 COUNTIES. RAP/RUC ANALYSIS INDICATING
THAT THE SHOWERS WERE MOST LIKELY DUE TO THE BACK RIGHT QUADRANT OF
A MID LEVEL/700MB JET LENDING ADDITIONAL FRONT...IN ADDITION TO THE
SLOW MOVING FRONT TO THE NORTH...TO THE LOW/MID LAYERS OF THE
ATMOSPHERE. BOTH THE RUC AND GFS NOT IN ANY HURRY TO MOVE THE 700MB
JET OUT OF THE AREA. WILL KEEP A SLIGHT CHANCE OF SHOWERS FROM
SEBASTIAN AND SEBASTIAN INLET SOUTH TO JUPITER INLET AND IN TO
OKEECHOBEE COUNTY OVERNIGHT. THE DRIER AIR NORTH DOES NOT WORK ITS
VERY FAR IF AT ALL INTO EAST CENTRAL FLORIDA THEREFORE WILL KEEP
SKIES CONSIDERABLY CLOUDY TO MOSTLY CLOUDY THE REST OF THE NIGHT.
PREVIOUS ZONES DISCUSSION
CURRENT...POST-FROPA TEMPERATURES MANAGED TO CLIMB
A FEW DEGREES MORE THAN THE MORNING UPDATE ANTICIPATED THROUGH
EARLY AFTERNOON... REACHING 70 OR A LITTLE ABOVE ACROSS THE NORTH.
WIND SHIFT ALONG THE VOLUSIA COAST...MARKING THE SECONDARY
FROPA...HAS DROPPED READINGS BACK INTO THE U50S. KMLB 88D AND
CCAFS MESONET WIND DATA SHOW THIS BOUNDARY HAS SLIPPED EVEN
FARTHER SOUTH ALONG COASTAL AREAS (BUT NOT YET INLAND)...REACHING
NRN BREVARD CO WITHIN THE LAST HR.
OVERNIGHT/FRI...SECONDARY COOL FRONT WILL BECOME DIFFUSE AS IT SAGS
INTO THE SRN HALF OF THE CWA. BOUNDARY BECOME BRIDGED BY DEVELOPING
NNE-NE FLOW FROM THE LARGE/STRONG ARCTIC HIGH BUILDING OVER THE CTRL-
ERN CONUS. SHALLOW POST FRONTAL N-NE WINDS CONTINUE TO UNDERCUT SWLY
H85 FLOW...WHICH ACTUALLY BACKS SOME TO S-SSE BY AFTERNOON. THIS
WILL KEEP THE CENTRAL AND SRN CWA SOCKED IN WITH CLOUDS/OCCASIONAL
LIGHT OVERRUNNING PRECIP THROUGH THE PERIOD. COOL BUT NOT COLD...BUT
WITH A CHILLY N-NE BREEZE. MINS GENERALLY IN THE 50S...SOME U40S PSBL
OVER THE FAR NORTH...AND L60S ALONG THE IMMEDIATE TREASURE COAST. FRI
MAXES MAINLY IN THE 60S...WITH L70S SOUTH.
FRIDAY NIGHT-SATURDAY NIGHT...FRONTAL BOUNDARY WILL MEANDER OVER
THE SOUTHERN PENINSULA DURING THE PERIOD. DEEP WEST/SOUTHWEST FLOW
OVERLYING SHALLOW NORTH/NORTHEAST LOFT WILL KEEP MULTI-LAYERED
CLOUDS HIGH THROUGH SATURDAY NIGHT. THE ISENTROPIC LIFT...
COMBINED WITH A SERIES OF WEAK MID-LEVEL IMPULSES WILL ALLOW FOR
PERIODS OF LIGHT RAIN/SHOWERS...WITH HIGHEST CHANCE ACROSS
SOUTHERN HALF OF THE CWA SATURDAY AND SATURDAY NIGHT. HAVE
INDICATED 30/40 PERCENT RAIN CHANCES...SIMILAR TO GFS MOS...BUT
CONSIDERABLY BELOW NAM MOS. WHILE QPF GENERALLY EXPECTED TO BE
LOW...DURATION OF LIGHT RAIN COULD RESULT IN NEAR 0.25 INCH TOTALS
IN FEW AREAS. MIN TEMPS FRI NIGHT IN THE 50S INLAND...BUT 60S
ALONG COAST WITH ONSHORE FLOW. MAX TEMPS SATURDAY NEAR
NORMAL...LOWER 70S NORTH TO UPPER 70S SOUTH. WARMER SATURDAY
NIGHT...RANGING FROM NEAR 60 FAR NW INTERIOR TO MID 70S FAR SE
COAST.
SUNDAY-WEDNESDAY...AS STRONG AREA OF HIGH PRESSURE MOVES OFF MID
ATLANTIC/NORTHEAST COAST SUNDAY...WINDS WILL CONTINUE TO VEER
ONSHORE AND PRESSURE GRADIENT WILL INCREASE...RESULTING IN BREEZY
CONDITIONS INLAND AND WINDY ALONG THE COAST. SURFACE BOUNDARY WILL
LIFT NORTHWARD LATE THIS WEEKEND...REBOUNDING TEMPS WITH GRADUAL
DECREASE OF CLOUD COVER AND POPS BY EARLY NEXT WEEK. TEMPERATURES
CLIMB A FEW DEGREES EACH DAY...BECOMING ABOVE NORMAL MONDAY... AND
PEAKING IN THE LOWER TO MID 80S TUE/WED...EXCEPT NEAR 80S ALONG
IMMEDIATE COAST.
&&
.AVIATION...SLOW MOVING FRONT CURRENTLY OVER CAPE CANAVERAL TO THE
TAMPA AREA. MOIST WEST TO SOUTHWEST WIND ABOVE 4000 FEET OVER NORTH
TO NORTHEAST WIND THAT WAS PUSHING A DRIER AIR MASS DOWN THE CENTER
OF THE STATE KEEPS MVFR CEILINGS THE REST OF THE NIGHT VERO BEACH
NORTH AND TEMPO IFR CEILINGS AND VISIBILITY IN SHOWERS VERO BEACH
SOUTH.
PREVIOUS AVIATION DISCUSSION
SMALL AREA OF HIGHER END IFR (BKN-OVC007-009) DEVELOPED INVOF VRB-
FPR A LITTLE AFTER 18Z BUT APPEARS TO HAVE BEEN LOCALIZED AND
TEMPORARY. CURRENT THINKING IS THAT THESE CIGS WILL REMAIN MVFR
BKN015-025. TO THE NORTH...CIGS VFR BKN-OVC040-060...BUT INCREASING
COOL NRLY FLOW MAY CAUSE THESE TO LOWER TO MVFR/020-030 AFTER 00Z.
CIGS TEMPORARILY BREAKING UP IN A SMALL AREAS NEAR/NORTH OF LEE-DAB
BUT EXPECT THESE TO FILL BACK IN AS CIGS NEAR OVC015 PERSIST JUST TO
THE NORTH OF THAT "SUCKER HOLE".
&&
.MARINE...
CURRENT-OVERNIGHT...BUOYS RECORDING NORTHWEST WINDS 10 TO 15 KNOTS
AND 2 TO 3 FOOT SEAS. WINDS AT BUOY 009 AND TRIDENT PIER AT CAPE
CANAVERAL SHOULD SHIFT TO THE NORTHEAST NEXT COUPLE OF HOURS AS THE
FRONT CLEARS THOSE SITES AND HIGH PRESSURE BUILDS IN BEHIND THE
FRONT.
PREVIOUS MARINE DISCUSSION AFTER COORD WITH MIA...MADE LATE CHANGE A
LITTLE AFTER 1PM TO BRIEFLY EXTEND SCA (FOR WINDS ONLY ) FOR ANOTHER
3HR (TIL 4PM) PLAN TO LET THIS EXPIRE WITH THE AFTERNOON ISSUANCE.
LULL IN WINDS/ SEAS TONIGHT TO BE SHORT-LIVED AS HIGH BUILDING TO
NORTH TIGHTENS LOCAL PGRAD...AND PUSHES SEAS BACK TO CAUTIONARY
LEVELS ON FRIDAY.
FRIDAY NIGHT-SUNDAY NIGHT...WINDS WILL VEER TO NORTHEAST FRIDAY
NIGHT AS HIGH PRESSURE BUILDS ACROSS THE EASTERN US. THE LOCAL
PRESSURE GRADIENT WILL TIGHTEN SATURDAY...CONTINUING THROUGH LATE
SUNDAY. INCREASING ONSHORE WINDS FORECAST TO REACH 20 TO 25 KNOTS
WITH HIGHER GUSTS. BOATING CONDITIONS WILL BECOME HAZARDOUS...AS
SEAS QUICKLY RESPOND TO THE INCREASING WINDS...BUILDING TO 5-7 FT
NEARSHORE AND 7-9 FT OFFSHORE SATURDAY. SEAS LIKELY TO PEAK IN THE
8-11 FT RANGE LATE SATURDAY THROUGH SUNDAY. MINOR BEACH EROSION
POSSIBLE.
MONDAY-WEDNESDAY...WINDS VEER SE BY MONDAY AND WEAKEN
SIGNIFICANTLY...BECOMING SOUTH AROUND 10 KT TUESDAY AND 10-15 KT
WEDNESDAY. SEAS SLOWLY SUBSIDE MONDAY TO 5-7 FT NEARSHORE AND 7-8
FT OFFSHORE...THEN GENERALLY NEAR 4 FT NEARSHORE TUE/WED AND 5 FT
OFFSHORE.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 51 63 55 70 / 0 10 20 40
MCO 51 68 55 78 / 10 20 20 30
MLB 58 68 62 74 / 30 40 20 40
VRB 61 70 66 77 / 40 40 30 40
LEE 48 64 51 75 / 0 10 20 30
SFB 50 66 53 73 / 0 20 20 30
ORL 51 67 55 75 / 10 20 20 30
FPR 61 71 68 78 / 40 40 30 40
&&
.MLB WATCHES/WARNINGS/ADVISORIES... NONE.
&&
$$
KELLY/WIMMER
Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
900 PM CST Thu Feb 26 2015
.UPDATE...
ISSUED AT 900 PM CST THU FEB 26 2015
Small area of clouds continues to slowly move south this evening.
Also, some isolated flurries are also still occurring under this
cloud cover. Expect this to continue, mainly in eastern areas of
the CWA. This will eventually clear up overnight. Current forecast
has a good handle on this and with temp trends the rest of the
night. No update planned at this time.
&&
.SHORT TERM...(Tonight)
ISSUED AT 249 PM CST THU FEB 26 2015
Will issue a wind chill advisory for areas along and north of a
Jacksonville to Springfield to Decatur to Paris line overnight into
mid Fri morning for wind chills of 15-24F below zero with the
coldest wind chills in Knox and Stark counties around dawn Friday.
Wind chills reach near or below 15F below near Galesburg around
midnight, and se toward I-72 later tonight. Lows overnight to
range from 5-10F below zero from the IL river valley nw to zero to
5F above in southeast IL from I-70 se. Broken to overcast low
clouds still cover much of IL with some clearing far west central
and northern IL near WI border. Still getting scattered light snow
showers and areas of flurries over central IL (visibilities as low as
2-5 miles) due to lingering moisture off lake MI along with a short
wave dropping se into the area. HRRR may be a bit too progressive in
clearing low clouds from north to south during early and mid
evening. Low clouds to likely decrease over IL river valley early
this evening, but thinking it may take until overnight for
decreasing of low clouds in southeast IL since short wave still
affecting southern counties tonight. Also lingered chance of
flurries from I-55 east late this afternoon and early evening and
into mid evening in southeast IL. Strong 1042 mb arctic high
pressure near the MT/ND and southern Saskatchewan border and ridging
SSE into the Great Plains to settle se into IA/MO by Friday morning
bringing dry weather and bitter cold temperatures overnight into Fri
morning. North winds 10-17 mph and gusts 18-24 mph this afternoon
will veer nw and decrease to 5-10 mph overnight.
&&
.LONG TERM...(Friday through Thursday)
ISSUED AT 249 PM CST THU FEB 26 2015
Morning upper air and satellite imagery depicts trough over the
central plains with clipper shortwave moving over IL, producing
continued light snow in strong 850mb cold air advection. Wave
continuing to move east and will break up in afternoon.
Ridge of high pressure to build in overnight, again producing wind
chills. Ridge to move off to the east through Friday and into
Saturday. By Saturday afternoon, overrunning from the next system
begins to develop into plains. NAM model brings snow into western IL
and feel not unreasonable. Will therefore add slight chc pops Sat
afternoon, with main pcpn Sat night to Sunday.
Models similar in development of frontal zone from western plains
low into Ozarks, with significant lift over boundary Saturday night.
This will push snow formation into central IL Saturday night,
continuing into Sunday. Main lift is Saturday night as upper wave
moves across great lakes, with pcpn lingering into Sunday. Diminshed
the pcpn Sun night as high pressure builds in.
Upper flow changes Monday to Tuesday, with pcpn again developing
into Monday night to Tuesday as surface low center develops in
plains and moves northeast, west of cwa though. The result is that
with this feature, area stays in the warm section and so pcpn starts
as freezing rain and changes to rain. Still uncertainty though, as
the operational models are very different on the timing of the
system movement. made few changes due to these differences.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
ISSUED AT 548 PM CST THU FEB 26 2015
clouds and light snow showers continue at SPI/DEC/CMI. When the
snow occurs, cigs are MVFR and vis is below 5SM. PIA and BMI just
have clouds, but VFR levels. All sites will remain mostly cloudy
most of the evening and since clouds are not diurnal, they will
continue for several hours after sunset. So, think clearing will
occur close to midnight. With all the low level moisture around
tomorrow, believe scattered lower SC or CU will develop in the
morning. Winds will be north-northwest early and then become
northwest close to midnight. With ridging over the area tomorrow,
winds will be light.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY from Midnight tonight to 10 AM CST Friday
FOR ILZ027>031-036>038-040>051-053-055-057.
&&
$$
UPDATE...Auten
SHORT TERM...07
LONG TERM...Goetsch
AVIATION...Auten
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
827 PM CST THU FEB 26 2015
.UPDATE...
827 PM CST
LAKE EFFECT SNOW IS STARTING TO WIND DOWN AS DRIER AIR MASS
ADVECTS INTO THE AREA ALLOWING FOR A WEAKENING OF THE BROKEN LES
BAND THAT HAD PERSISTED ALL DAY. AS PROGRESSIVELY DRIER AIR
CONTINUED TO FILTER IN TONIGHT AND EVENTUALLY ONSHORE COMPONENT TO
FLOW WEAKENS WOULD ANTICIPATE LES TO END IN PORTER COUNTY LATER
THIS EVENING OR JUST PAST MIDNIGHT. GIVEN EXPECTATIONS AND RECENT
RADAR TRENDS MAY SHORTEN THE DURATION OF THE LAKE EFFECT SNOW
WARNING IN THE NEXT HOUR OR TWO IF NOT CANCEL IT OUTRIGHT.
ELSEWHERE CLOUDINESS OVER SOUTHERN PORTIONS OF THE CWA IS LIKELY
TO SLOWLY DISSIPATE AND MOVE OUT LEAVING SKIES FAIRLY CLEAR ACROSS
THE AREA. CENTER OF THE HIGH PRESSURE IS STILL HUNDREDS OF MILE TO
OUR NORTHWEST BUT WITH FRESH SNOW PACK WOULD EXPECT GRADIENT TO BE
WEAK ENOUGH FOR WINDS TO FURTHER DECOUPLE OVERNIGHT...ESPECIALLY
WITH HIGH GROWING CLOSER IN TIME. SUSPECT THAT THE WIND CHILL
ADVISORY WILL BE HARD PRESSED TO VERIFY MOST AREAS WITH THE
TYPICALLY COLDER VALLEYS LIKELY SEEING WINDS GO CALM...LIKELY KRPJ
AND KFRD ALREADY HAVE OR WINDS TO STAY UP ENOUGH TO KEEP TEMPS
FROM TANKING. THE TOOTHPASTE IS OUT OF THE PROVERBIAL TUBE SO NOT
PLANNING ANY CHANGES TO THE WIND CHILL ADVISORY SINCE A FEW
LOCATIONS COULD TAG ADVISORY FOR AN HOUR OR TWO AND IT WILL BE
VERY COLD.
IZZI
&&
.SHORT TERM...
THROUGH SATURDAY...
243 PM...LAKE EFFECT IS NOW ORGANIZING INTO A SINGLE BAND AS
WINDS TURN MORE NORTHWEST ACROSS NORTHEAST IL AND THIS BAND IS
SHIFTING TO THE SOUTHEAST AND WILL BE OUT OF COOK COUNTY IN THE
NEXT HOUR OR SO. WILL BE EXPIRING LAKE COUNTY IL FROM THE WARNING
AND FOR NOW WILL LET COOK COUNTY RIDE UNTIL 6 PM...BUT IF CURRENT
TRENDS CONTINUE...IT PROBABLY WILL BE CANCELED EARLY.
HI RES GUIDANCE IS IN REASONABLE AGREEMENT THAT THE LAKE EFFECT
BAND WILL SHIFT INTO PORTER COUNTY BY EARLY/MID EVENING...SO
EXPECTED AMOUNTS IN NORTHERN LAKE COUNTY INDIANA ARE A BIT
UNCERTAIN BUT WITH RATES OF 1-2 INCHES PER HOUR IN THE BAND...ITS
POSSIBLE SOME ISOLATED AMOUNTS OF 3 TO 6 INCHES WILL BE POSSIBLE.
MORE CONFIDENCE WITH AMOUNTS INTO NORTHERN PORTER COUNTY AS THE
BAND REMAINS THERE FROM MID EVENING THROUGH THE OVERNIGHT HOURS
WITH LOCALLY 4 TO 7 INCHES...PERHAPS MOSTLY NEAR THE LAKE. THE
BAND THEN BEGINS TO SHIFT OUT OF THE LAKE TOWARD MORNING. SO NOT
PLANNING ANY CHANGES TO THE WARNING END TIME FOR EITHER LAKE OR
PORTER COUNTIES...THOUGH CONFIDENCE REGARDING WHEN EXACTLY PRECIP
ENDS IS A BIT UNCERTAIN.
HIGH PRESSURE BUILDS ACROSS THE MIDWEST TONIGHT AND THEN MOVES
ACROSS THE AREA ON FRIDAY. WINDS WILL SLOWLY DIMINISH OVERNIGHT
BUT LIKELY REMAIN IN THE 5-10 MPH. THIS COMBINED WITH TEMPS
DROPPING WELL BELOW ZERO AWAY FROM CHICAGO WILL RESULT IN WINDS
CHILLS 20 BELOW TO 25 BELOW ZERO ACROSS THE NORTHERN CWA AND INTO
THE 15 BELOW RANGE SOUTH OF I-80. VALUES ARE BIT MARGINAL INTO
CHICAGO AND ALONG THE I-80 CORRIDOR BUT PLAN TO ISSUE A WIND
CHILL ADVISORY OVERNIGHT INTO FRIDAY MORNING GENERALLY ALONG AND
NORTH OF I-80 IN ILLINOIS.
DESPITE THE LIGHT WINDS AND SUNNY SKIES ON FRIDAY AS THE HIGH
SLOWLY MOVES ACROSS THE AREA...THE AIRMASS WILL REMAIN VERY COLD
WITH HIGHS ONLY REACHING THE MID TO PERHAPS UPPER TEENS. TEMPS
WILL LIKELY TANK FRIDAY NIGHT AS THE HIGH SHIFTS EAST AND LIGHT
WINDS TURN SOUTHERLY. SATURDAY WILL BE DRY AND A BIT WARMER WITH
HIGHS IN THE LOWER/MID 20S WITH INCREASING CLOUDS IN THE
AFTERNOON. CMS
&&
.LONG TERM...
SATURDAY NIGHT THROUGH THURSDAY...
THE TIME FRAME WILL START OUT ACTIVE AS A PERIOD OF ACCUMULATING
SNOW IS APPEARING LIKELY SATURDAY NIGHT INTO SUNDAY. STEADILY
INCREASING UPPER LEVEL FLOW OUT AHEAD OF DIGGING TROUGH TO THE
NORTH WILL ALLOW SHORT WAVE ENERGY TO TRAVERSE THE REGION DURING
THIS PERIOD...WHILE ONGOING WAA PERSISTS. THIS SHOULD ALLOW SNOW
TO SPREAD NORTHEAST ACROSS THE CWA DURING THE EVENING HOURS WITH
SNOW LIKELY ACROSS MUCH OF THE CWA AFTER THE MIDNIGHT TIME
FRAME...THEN LIKELY CONTINUING INTO SUNDAY AFTERNOON. MOST
GUIDANCE IN AGREEMENT WITH OVERALL LARGE SCALE SETUP DURING THIS
TIME AND EVEN WITH THIS SNOW SPREADING OVER THE CWA.
HOWEVER...THERE DOES APPEAR TO BE SOME TIMING DIFFERENCES OF THE
ONSET AND TIMING OF BEST SNOWFALL. SO I DO FEEL IT WILL SNOW AND
HAVE LIKELY POPS OVER THE ENTIRE CWA LATE SATURDAY NIGHT INTO
SUNDAY MORNING...BUT DID NOT GO TO CATEGORICAL BASED ON THE
PREVIOUSLY MENTIONED UNCERTAINTIES. ONLY MINOR CHANGES MADE TO THE
CURRENT SNOW FORECAST WITH THE BEST FORCING AND HIGHEST SNOWFALL
TOTALS CURRENTLY EXPECTED TO BE SOUTH OF I80. WHILE MOST OF THE
CWA WILL LIKELY OBSERVE ACCUMULATING SNOWFALL...THE SOUTHERN CWA
COULD APPROACH ADVISORY TYPE SNOW. HOWEVER I WONDER IF MY CURRENT
TOTAL MIGHT BE A LITTLE TOO HIGH...ESPECIALLY WITH THE ANTICIPATED
DRIVING MECHANISMS OF THIS SNOW...BUT THE LONGER DURATION OF THIS
LIGHT TO AT TIME MODERATE SNOW COULD HELP FOR THE CURRENT FORECAST
TOTALS. SYSTEM SNOW WILL DEPART TO THE EAST LATE SUNDAY AND SUNDAY
EVENING...AS HIGH PRESSURE BUILDS ACROSS THE REGION.
EARLY NEXT WEEK APPEARS TO BEGIN QUIET...BUT WITH ACTIVE WEATHER
RETURNING THROUGH MIDWEEK. HIGHLY AMPLIFIED PATTERN WITH UPPER
LEVEL RIDGE OVER THE EASTERN US AND A DIGGING TROUGH OVER THE
WESTERN CONUS WILL BE IN PLACE ON TUESDAY...AS DEEPENING SURFACE
LOW APPROACHES THE CWA FROM THE SOUTHWEST. STRONG WARM AIR AND
MOIST ADVECTION IS ANTICIPATED MONDAY NIGHT AND ESPECIALLY
TUESDAY/TUESDAY NIGHT. THIS WILL NOT ONLY PROVIDE THE POTENTIAL
FOR INITIAL VARYING PRECIP TYPE BUT WITH ALSO STEADIER
RAINFALL...AS A BROAD AREA OF PRECIP IS EXPECTED TO ACCOMPANY THIS
SYSTEM. EC AND GFS SIMILAR WITH REGARDS TO WAA...BUT WITH THE GFS
NOT AS ROBUST WITH THE MOISTURE ADVECTION AS THE EC IS APPEARING
TO BE. IF THE EC WERE TO VERIFY...THEN SURFACE DEWPOINTS COULD
APPROACH 50 DEG AND 850MB DEWPOINTS APPROACHING 10-11C. THIS WILL
BE CONCERNING FOR POSSIBLE HYDRO ISSUES...ESPECIALLY WITH THE
ANTICIPATED SNOW THIS WEEKEND. THERMAL PROFILES SUPPORTIVE OF ALL
RAIN ON TUESDAY AND ALTHOUGH I HAVENT INCLUDED THUNDER IN THE
GRIDS AT THIS TIME...WILL NEED TO MONITOR THIS POTENTIAL AS
WELL...ESPECIALLY FOR THE SOUTHERN CWA.
RODRIGUEZ
&&
.CLIMATE...
TEMPERATURES ARE FORECAST ONCE AGAIN TO BE CLOSE OR BREAK THE
FOLLOWING DAILY RECORDS THROUGH THE END OF THE MONTH...INCLUDING
ONE ON FRIDAY IN ROCKFORD THAT WAS SET JUST LAST WINTER:
ROCKFORD...
FRIDAY FEB 27TH LOW MAXIMUM: 15 IN 2014
SATURDAY FEB 28TH LOW: -7 IN 1962
SATURDAY FEB 28TH LOW MAXIMUM: 17 IN 1962
CHICAGO...
FRIDAY FEB 27TH LOW: -6 IN 1897
SATURDAY FEB 28TH LOW: 0 IN 1884
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 03Z...
* NONE.
RC/IZZI
//DISCUSSION...UPDATED 00Z...
HIGH PRESSURE SPREADING SOUTHEAST FROM THE NORTHERN PLAINS TO THE
MID MISSISSIPPI VALLEY WILL RESULT IN QUIET AVIATION CONDITIONS
THROUGH THE TAF PERIOD. NORTHWEST WINDS WILL DIMINISH TONIGHT AND
BECOME WESTERLY ON FRIDAY...WITH SPEEDS GENERALLY LESS THAN 10 KT.
RC
//ORD AND MDW CONFIDENCE...UPDATED 03Z...
* HIGH IN ALL ELEMENTS.
RC/IZZI
//OUTLOOK FOR ORD/MDW FOR 12Z SATURDAY-12Z THURSDAY...UPDATED 00Z...
SATURDAY...VFR THEN SNOW DEVELOPING SATURDAY NIGHT. IFR LIKELY.
SUNDAY...PERIODS OF ACCUMULATING SNOW ENDING BY LATE AFTERNOON.
IFR LIKELY.
MONDAY...VFR THEN CHANCE OF WINTRY MIX AND IFR MONDAY NIGHT.
TUESDAY...RAIN AND IFR LIKELY...POSSIBLY ENDING AS LIGHT SNOW
TUESDAY NIGHT. IFR
WEDNESDAY...MVFR POSSIBLE.
RC
&&
.MARINE...
215 PM CST
THE FAR NORTHERN PORTIONS OF THE LAKE REMAINS ICE COVERED AS DO
THE SOUTHERN NEARSHORE WATERS. THERE...WAVES HAVE REMOVED FROM THE
FORECAST FOR THESE AREAS.
HIGH PRESSURE EXTENDS FROM THE NORTHERN PLAINS...WITH A CENTRAL
PRESSURE OF 30.8 INCHES...SOUTH THROUGH TEXAS AND EAST ACROSS THE
GREAT LAKES. THE CENTER OF THE HIGH WILL CONTINUE TO DROP TO THE
SOUTHEAST...TO THE UPPER MISSOURI VALLEY BY FRIDAY MORNING. WITH
RIDGE AXIS EXTENDING ACROSS LAKE MICHIGAN...A CONVERGENCE BAND HAS
SET UP WITH A PLUME OF LAKE EFFECT SNOW MOVING ACROSS THE SOUTHERN
PORTIONS OF THE LAKE. AS THE CENTER OF THE HIGH CONTINUES TO
SETTLE INTO THE OHIO VALLEY FRIDAY AND FRIDAY NIGHT...WINDS OVER
THE LAKE WILL BACK FROM NORTHERLY TO WESTERLY FRIDAY NIGHT AND
SATURDAY. AS THE HIGH MOVES OFF TO THE EAST...A WEAK COLD FRONT IS
EXPECTED TO CROSS THE UPPER MISSISSIPPI VALLEY SATURDAY
NIGHT...BACKING WINDS OVER THE LAKE TO SOUTHWESTERLY. THROUGH THIS
PERIOD...WINDS WILL BE ON A GENERAL WEAKENING TREND. THE WEAK COLD
FRONT IS EXPECTED TO SWEEP ACROSS THE LAKE SUNDAY EVENING WITH
ANOTHER ARCTIC HIGH QUICKLY FOLLOWING IN IT`S WAKE. THIS HIGH WILL
TAKE A MORE NORTHERLY TRACK...WITH THE CENTER OF THE HIGH CROSSING
THE LAKE SUNDAY NIGHT AND MONDAY...LEADING TO A SHORT PERIOD OF
LIGHT AND VARIABLE WINDS. THE HIGH SHOULD THEN PUSH EAST OF THE
LAKE MONDAY AND MONDAY NIGHT AS LOW PRESSURE DEVELOPS OVER
KANSAS/NEBRASKA IN THE LEE OF THE ROCKIES...SETTING UP A PERIOD OF
SOUTHEAST WINDS AS AN ASSOCIATED WARM FRONT EXTENDS EAST OF THE
LOW...TO THE OHIO VALLEY. THE LOW IS EXPECTED TO DEEPEN TO 29.1
INCHES AS IT TRACKS NORTHEAST AND CROSSES THE MIDDLE OF LAKE
MICHIGAN TUESDAY EVENING.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WIND CHILL ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022...2
AM FRIDAY TO 9 AM FRIDAY.
IN...LAKE EFFECT SNOW WARNING...INZ002 UNTIL 6 AM FRIDAY.
LM...NONE.
&&
$$
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
548 PM CST Thu Feb 26 2015
.SHORT TERM...(Tonight)
ISSUED AT 249 PM CST THU FEB 26 2015
Will issue a wind chill advisory for areas along and north of a
Jacksonville to Springfield to Decatur to Paris line overnight into
mid Fri morning for wind chills of 15-24F below zero with the
coldest wind chills in Knox and Stark counties around dawn Friday.
Wind chills reach near or below 15F below near Galesburg around
midnight, and se toward I-72 later tonight. Lows overnight to
range from 5-10F below zero from the IL river valley nw to zero to
5F above in southeast IL from I-70 se. Broken to overcast low
clouds still cover much of IL with some clearing far west central
and northern IL near WI border. Still getting scattered light snow
showers and areas of flurries over central IL (visibilities as low as
2-5 miles) due to lingering moisture off lake MI along with a short
wave dropping se into the area. HRRR may be a bit too progressive in
clearing low clouds from north to south during early and mid
evening. Low clouds to likely decrease over IL river valley early
this evening, but thinking it may take until overnight for
decreasing of low clouds in southeast IL since short wave still
affecting southern counties tonight. Also lingered chance of
flurries from I-55 east late this afternoon and early evening and
into mid evening in southeast IL. Strong 1042 mb arctic high
pressure near the MT/ND and southern Saskatchewan border and ridging
SSE into the Great Plains to settle se into IA/MO by Friday morning
bringing dry weather and bitter cold temperatures overnight into Fri
morning. North winds 10-17 mph and gusts 18-24 mph this afternoon
will veer nw and decrease to 5-10 mph overnight.
&&
.LONG TERM...(Friday through Thursday)
ISSUED AT 249 PM CST THU FEB 26 2015
Morning upper air and satellite imagery depicts trough over the
central plains with clipper shortwave moving over IL, producing
continued light snow in strong 850mb cold air advection. Wave
continuing to move east and will break up in afternoon.
Ridge of high pressure to build in overnight, again producing wind
chills. Ridge to move off to the east through Friday and into
Saturday. By Saturday afternoon, overrunning from the next system
begins to develop into plains. NAM model brings snow into western IL
and feel not unreasonable. Will therefore add slight chc pops Sat
afternoon, with main pcpn Sat night to Sunday.
Models similar in development of frontal zone from western plains
low into Ozarks, with significant lift over boundary Saturday night.
This will push snow formation into central IL Saturday night,
continuing into Sunday. Main lift is Saturday night as upper wave
moves across great lakes, with pcpn lingering into Sunday. Diminshed
the pcpn Sun night as high pressure builds in.
Upper flow changes Monday to Tuesday, with pcpn again developing
into Monday night to Tuesday as surface low center develops in
plains and moves northeast, west of cwa though. The result is that
with this feature, area stays in the warm section and so pcpn starts
as freezing rain and changes to rain. Still uncertainty though, as
the operational models are very different on the timing of the
system movement. made few changes due to these differences.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
ISSUED AT 548 PM CST THU FEB 26 2015
clouds and light snow showers continue at SPI/DEC/CMI. When the
snow occurs, cigs are MVFR and vis is below 5SM. PIA and BMI just
have clouds, but VFR levels. All sites will remain mostly cloudy
most of the evening and since clouds are not diurnal, they will
continue for several hours after sunset. So, think clearing will
occur close to midnight. With all the low level moisture around
tomorrow, believe scattered lower SC or CU will develop in the
morning. Winds will be north-northwest early and then become
northwest close to midnight. With ridging over the area tomorrow,
winds will be light.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY from Midnight tonight to 10 AM CST Friday
FOR ILZ027>031-036>038-040>051-053-055-057.
&&
$$
SHORT TERM...07
LONG TERM...Goetsch
AVIATION...Auten
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1213 PM CST WED FEB 25 2015
.UPDATE...
ISSUED AT 1159 AM CST WED FEB 25 2015
CONTINUE TO ASSESS THE EVOLUTION OF THE CLIPPER SYSTEM TO TRY AND
RESOLVE ANY CHANGES TO HEADLINES LATER THIS AFTERNOON. INITIAL
THOUGHTS THAT HEAVIER FORCING/H8-H7 MB BASED FRONTOGENETICAL BAND
WITH THE HEAVY SNOW RATES CURRENTLY ACRS NE IA INTO WEST CENTRAL
IA MAY EXPAND SOME AND DROP SOUTHEASTWARD ACRS THE WESTWARD THIRD
FROM MID AFTERNOON TO EARLY EVENING...AND EXPAND ACRS THE SOUTHERN
THIRD OF THE DVN CWA THIS EVENING THROUGH MIDNIGHT WITH GREATEST
RATE OF ACCUMULATIONS OCCURRING UNDER IT. THE 12Z 4KM WRF MAY BE ON
TO SOMETHING AND SHOWS SIMILAR HANDLING. SOME CONCERN IF THE
BAND PROGRESSES LIKE THE WRF SHOWS THAT SNOW AMOUNTS IN THE
NORTHWESTERN HALF OF THE WARNING AREA MAY BE TOO HIGH BY A FEW
INCHES...THE CURRENTLY ADVERTISED 6-9 INCHES MAY BE MORE LIKE 4-7
INCHES IN THOSE AREAS. NORTHEASTERN ADVISORY AREAS MORE LIKE 2-4
INCHES AS OPPOSED TO 3-6 INCHES. ONGOING AMOUNTS SOUTH OF I80
STILL LOOK ON TARGET FOR THE MOST PART WITH BULK OF ACCUMS DOWN
THERE OCCURRING AFTER 5 PM THIS EVENING. THERE MAY BE A NEED TO
EXPAND ADVISORY INTO BUREAU COUNTY IF THE WESTERN PART OF THAT
COUNTY WILL BE IN LINE FOR WIDESPREAD 3-4 INCHES. CHALLENGES
APLENTY FOR THE AFTERNOON. ..12..
&&
.SYNOPSIS...
ISSUED AT 330 AM CST WED FEB 25 2015
AT 330 AM...MID LEVEL CLOUDS WERE STREAMING INTO THE AREA AHEAD OF
A ROBUST CLIPPER SYSTEM. SNOW WAS CONTINUING TO DEVELOP ACROSS
PARTS OF SOUTH DAKOTA AND SOUTHWEST MINNESOTA. EARLY MORNING
TEMPERATURES WERE IN THE TEENS TO LOWER 20S AT MOST LOCATIONS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 330 AM CST WED FEB 25 2015
THE MAIN FORECAST ISSUE IS THE IMPENDING POTENT CLIPPER SYSTEM AND
ASSOCIATED SNOWFALL AMOUNTS AND COVERAGE.
LOOKING AT THE VARIOUS SYNOPTIC AND HIGH RES MODELS...LATEST
TRENDS HAVE BEEN TOWARD HIGHER SNOWFALL AMOUNTS AND A SLIGHTLY
FARTHER NORTH AXIS OF THE HEAVIEST SNOW. THE INITIAL ISSUE IS
TIMING OF THE ONSET OF SNOW...DEPENDENT ON HOW THE DEFORMATION
ZONE/DRY SLOT SET UP. THE WRF IS A BIT FASTER IN BRINGING SNOW
INTO THE WEST THIS MORNING...WHILE THE RAP HAS A MORE PRONOUNCED
DRY SLOT EARLY IN THE EVENT. FOR PURPOSES OF THE FORECAST GRIDS
AND HEADLINES...HAVE GONE WITH THE EARLIER TIMING...WHICH CAN BE
ADJUSTED THROUGH THE DAY.
GIVEN THE STRENGTH AND DEPTH OF THE FORCING THROUGH THE DENDRITIC
LAYER...THE HIGHER SNOWFALL AMOUNTS LOOK REASONABLE BASED ON
AVERAGE SNOW RATIOS THROUGH THE BULK OF THE EVENT IN THE 14-19:1
RANGE. ALSO FAVORED CONSENSUS QPF...WHICH IS SLIGHTLY HIGHER TO
THE NORTH THAN WPC VALUES. THE END RESULT IS ROUGHLY 6-9 INCHES
FROM INDEPENDENCE...TO WAPELLO...FORT MADISON AND POINTS EAST.
HAVE UPGRADED THESE AREAS TO A WINTER STORM WARNING. FROM
DUBUQUE...THROUGH THE QUAD CITIES...WEST CENTRAL ILLINOIS...AND
FAR NORTHEAST MISSOURI...EXPECTING GENERAL 3-6 INCH AMOUNTS WITH A
WINTER WEATHER ADVISORY IN EFFECT. LOCALLY ENHANCED HIGHER SNOWFALL
AMOUNTS ARE NOT OUT OF THE QUESTION IN THE ADVISORY AREA.
ADJUSTMENTS TO SNOWFALL AMOUNTS/HEADLINES ARE INEVITABLE AS WE
HEAD THROUGH THE DAY AND INTO THIS EVENING.
PEAK SNOWFALL INTENSITY EXPECTED IN THE AFTERNOON/EVENING...WHICH
WILL MAKE FOR A HAZARDOUS COMMUTE WITH SNOW COVERED ROADS AND
REDUCED VISIBILITY. A NORTHWEST WIND AROUND 15 MPH WITH HIGHER
GUSTS WILL LIKELY PRODUCE SOME SHALLOW DRIFTING SNOW AT TIMES. THE
SNOW WILL TAPER OFF FROM NORTHWEST TO SOUTHEAST LATE TONIGHT INTO
THURSDAY MORNING.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 330 AM CST WED FEB 25 2015
THURSDAY AND FRIDAY...VERY COLD PERIOD AS ARCTIC ~1042 MB HIGH
BUILDS INTO THE MIDWEST. FRESH POWDERY SNOW ON THE GROUND/LIGHT
WINDS (POSSIBLY DECOUPLED AT TIMES)/AND MAINLY CLEAR SKIES WILL SET
THE STAGE FOR VERY COLD OVERNIGHT LOWS. CURRENT FORECAST FAVORS THE
RAW GFS/ECMWF AS SUPERBLEND/NAM SEEM TO BE TOO WARM.
EXPECT WIDESPREAD LOWS BETWEEN -10 TO -15 F WHICH WOULD BE NEAR
RECORD TERRITORY FOR LATE FEBRUARY...SINGLE DIGIT SUB-ZERO LOWS ARE
MORE LIKELY SOUTH OF BURLINGTON. WINDS WILL REMAIN ON THE LIGHT SIDE
BUT EVEN AT 5-7 KTS THEY WILL BE ENOUGH TO CREATE DANGEROUS WIND
CHILLS BETWEEN -20 TO -30 F AT TIMES. VALUES NEAR -30 F SHOULD BE
RELATIVELY ISOLATED AND SHORT-LIVED. HIGHS ARE FORECAST TO BE IN THE
UPPER SINGLE DIGITS TO MID TEENS.
SATURDAY AND SUNDAY...SIGNIFICANT PATTERN CHANGE WILL OCCUR DURING
THIS TIME AS UPPER JET DIGS OUT A LARGE TROUGH OVER THE WESTERN U.S.
WHICH WILL CAUSE A BIG SHIFT IN THE ORIENTATION OF THE 850 MB
BAROCLINIC ZONE TO A SW-NE DIRECTION.
THERE HAS BEEN A CONSISTENT SIGNAL OF SIGNIFICANT LOW/MID LEVEL
MOISTURE ADVECTION FROM THE SW U.S. AND FROM THE GULF OF MEXICO FOR
SAT NIGHT INTO SUN. THEREFORE...A PERIOD OF SNOW IS LIKELY WITH
AMOUNTS UNCERTAIN THIS FAR OUT. WITH THE LACK OF A STRONG SHORTWAVE
TROUGH/VORTICITY MAX...MODELS DEVELOP LINEAR-LOOKING FRONTAL PRECIP
AND DO NOT DEVELOP A COHERENT SFC LOW WHICH WOULD PUT SOMEWHAT OF A
LIMIT ON THIS SYSTEM. DAYTIME TEMPS WILL BE IN THE 20S ON SAT AND
THE UPPER 20S TO LOWER 30S ON SUN.
MONDAY AND TUESDAY...CHANCE OF PRECIP MORE LIKELY LATER IN THE DAY
AND INTO TUE. MODELS STILL STRUGGLING WITH WHEN TO EJECT ORGANIZED
500 MB VORTICITY MAX OUT OF THE FOUR CORNERS AREA. THE GFS HAS A
WELL ORGANIZED SFC LOW TRACKING FROM OKLAHOMA TO NORTHERN INDIANA
WHICH IS FAVORABLE FOR WIDESPREAD PRECIP IN THE DVN CWA. WARMER AIR
ALOFT MAY MAKE IT FAR ENOUGH NORTH TO BRING VARYING PRECIP TYPES TO
PORTIONS OF THE FORECAST AREA. STAY TUNED. EARLY LOOK AT FORECAST
HIGHS ARE IN THE UPPER 20S TO MIDDLE 30S ON TUE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1147 AM CST WED FEB 25 2015
SNOW COMING IN AND SATURATING FOR LOW MVFR TO LIFR CONDITIONS AT
DBQ AND CID ALREADY...MLI BY 1-2 PM AND BRL MAINLY 2-3 PM. EAST
WINDS TO BACK TO THE NORTH TO NORTHEAST THIS EVENING INTO THU
MORNING. 10-20 KT WINDS COMBINING WITH FALLING SNOW COMPOUNDING
VSBYS THIS AFTERNOON THOUGH THE EVENING. CONDITIONS TO IMPROVE FROM
NORTH TO SOUTH AFTER MIDNIGHT TONIGHT THROUGH MID THU MORNING...
FIRST AT DBQ/CID WHICH MAY BE MVFR BY SUNRISE. ..12..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...WINTER WEATHER ADVISORY UNTIL 6 AM CST THURSDAY FOR CLINTON-
DELAWARE-DUBUQUE-JACKSON-JONES-SCOTT.
WINTER STORM WARNING UNTIL 6 AM CST THURSDAY FOR CEDAR-DES
MOINES-HENRY IA-JEFFERSON-LEE-LOUISA-MUSCATINE-VAN BUREN.
WINTER STORM WARNING UNTIL 3 AM CST THURSDAY FOR BENTON-BUCHANAN-
IOWA-JOHNSON-KEOKUK-LINN-WASHINGTON.
IL...WINTER WEATHER ADVISORY UNTIL 6 AM CST THURSDAY FOR HENRY IL-
MERCER-ROCK ISLAND.
WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 9 AM CST
THURSDAY FOR HANCOCK-HENDERSON-MCDONOUGH-WARREN.
MO...WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 9 AM CST
THURSDAY FOR CLARK-SCOTLAND.
&&
$$
UPDATE...12
SYNOPSIS...RP KINNEY
SHORT TERM...RP KINNEY
LONG TERM...UTTECH
AVIATION...12
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
752 AM CST WED FEB 25 2015
.SYNOPSIS...
ISSUED AT 330 AM CST WED FEB 25 2015
AT 330 AM...MID LEVEL CLOUDS WERE STREAMING INTO THE AREA AHEAD OF
A ROBUST CLIPPER SYSTEM. SNOW WAS CONTINUING TO DEVELOP ACROSS
PARTS OF SOUTH DAKOTA AND SOUTHWEST MINNESOTA. EARLY MORNING
TEMPERATURES WERE IN THE TEENS TO LOWER 20S AT MOST LOCATIONS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 330 AM CST WED FEB 25 2015
THE MAIN FORECAST ISSUE IS THE IMPENDING POTENT CLIPPER SYSTEM AND
ASSOCIATED SNOWFALL AMOUNTS AND COVERAGE.
LOOKING AT THE VARIOUS SYNOPTIC AND HIGH RES MODELS...LATEST
TRENDS HAVE BEEN TOWARD HIGHER SNOWFALL AMOUNTS AND A SLIGHTLY
FARTHER NORTH AXIS OF THE HEAVIEST SNOW. THE INITIAL ISSUE IS
TIMING OF THE ONSET OF SNOW...DEPENDENT ON HOW THE DEFORMATION
ZONE/DRY SLOT SET UP. THE WRF IS A BIT FASTER IN BRINGING SNOW
INTO THE WEST THIS MORNING...WHILE THE RAP HAS A MORE PRONOUNCED
DRY SLOT EARLY IN THE EVENT. FOR PURPOSES OF THE FORECAST GRIDS
AND HEADLINES...HAVE GONE WITH THE EARLIER TIMING...WHICH CAN BE
ADJUSTED THROUGH THE DAY.
GIVEN THE STRENGTH AND DEPTH OF THE FORCING THROUGH THE DENDRITIC
LAYER...THE HIGHER SNOWFALL AMOUNTS LOOK REASONABLE BASED ON
AVERAGE SNOW RATIOS THROUGH THE BULK OF THE EVENT IN THE 14-19:1
RANGE. ALSO FAVORED CONSENSUS QPF...WHICH IS SLIGHTLY HIGHER TO
THE NORTH THAN WPC VALUES. THE END RESULT IS ROUGHLY 6-9 INCHES
FROM INDEPENDENCE...TO WAPELLO...FORT MADISON AND POINTS EAST.
HAVE UPGRADED THESE AREAS TO A WINTER STORM WARNING. FROM
DUBUQUE...THROUGH THE QUAD CITIES...WEST CENTRAL ILLINOIS...AND
FAR NORTHEAST MISSOURI...EXPECTING GENERAL 3-6 INCH AMOUNTS WITH A
WINTER WEATHER ADVISORY IN EFFECT. LOCALLY ENHANCED HIGHER SNOWFALL
AMOUNTS ARE NOT OUT OF THE QUESTION IN THE ADVISORY AREA.
ADJUSTMENTS TO SNOWFALL AMOUNTS/HEADLINES ARE INEVITABLE AS WE
HEAD THROUGH THE DAY AND INTO THIS EVENING.
PEAK SNOWFALL INTENSITY EXPECTED IN THE AFTERNOON/EVENING...WHICH
WILL MAKE FOR A HAZARDOUS COMMUTE WITH SNOW COVERED ROADS AND
REDUCED VISIBILITY. A NORTHWEST WIND AROUND 15 MPH WITH HIGHER
GUSTS WILL LIKELY PRODUCE SOME SHALLOW DRIFTING SNOW AT TIMES. THE
SNOW WILL TAPER OFF FROM NORTHWEST TO SOUTHEAST LATE TONIGHT INTO
THURSDAY MORNING.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 330 AM CST WED FEB 25 2015
THURSDAY AND FRIDAY...VERY COLD PERIOD AS ARCTIC ~1042 MB HIGH
BUILDS INTO THE MIDWEST. FRESH POWDERY SNOW ON THE GROUND/LIGHT
WINDS (POSSIBLY DECOUPLED AT TIMES)/AND MAINLY CLEAR SKIES WILL SET
THE STAGE FOR VERY COLD OVERNIGHT LOWS. CURRENT FORECAST FAVORS THE
RAW GFS/ECMWF AS SUPERBLEND/NAM SEEM TO BE TOO WARM.
EXPECT WIDESPREAD LOWS BETWEEN -10 TO -15 F WHICH WOULD BE NEAR
RECORD TERRITORY FOR LATE FEBRUARY...SINGLE DIGIT SUB-ZERO LOWS ARE
MORE LIKELY SOUTH OF BURLINGTON. WINDS WILL REMAIN ON THE LIGHT SIDE
BUT EVEN AT 5-7 KTS THEY WILL BE ENOUGH TO CREATE DANGEROUS WIND
CHILLS BETWEEN -20 TO -30 F AT TIMES. VALUES NEAR -30 F SHOULD BE
RELATIVELY ISOLATED AND SHORT-LIVED. HIGHS ARE FORECAST TO BE IN THE
UPPER SINGLE DIGITS TO MID TEENS.
SATURDAY AND SUNDAY...SIGNIFICANT PATTERN CHANGE WILL OCCUR DURING
THIS TIME AS UPPER JET DIGS OUT A LARGE TROUGH OVER THE WESTERN U.S.
WHICH WILL CAUSE A BIG SHIFT IN THE ORIENTATION OF THE 850 MB
BAROCLINIC ZONE TO A SW-NE DIRECTION.
THERE HAS BEEN A CONSISTENT SIGNAL OF SIGNIFICANT LOW/MID LEVEL
MOISTURE ADVECTION FROM THE SW U.S. AND FROM THE GULF OF MEXICO FOR
SAT NIGHT INTO SUN. THEREFORE...A PERIOD OF SNOW IS LIKELY WITH
AMOUNTS UNCERTAIN THIS FAR OUT. WITH THE LACK OF A STRONG SHORTWAVE
TROUGH/VORTICITY MAX...MODELS DEVELOP LINEAR-LOOKING FRONTAL PRECIP
AND DO NOT DEVELOP A COHERENT SFC LOW WHICH WOULD PUT SOMEWHAT OF A
LIMIT ON THIS SYSTEM. DAYTIME TEMPS WILL BE IN THE 20S ON SAT AND
THE UPPER 20S TO LOWER 30S ON SUN.
MONDAY AND TUESDAY...CHANCE OF PRECIP MORE LIKELY LATER IN THE DAY
AND INTO TUE. MODELS STILL STRUGGLING WITH WHEN TO EJECT ORGANIZED
500 MB VORTICITY MAX OUT OF THE FOUR CORNERS AREA. THE GFS HAS A
WELL ORGANIZED SFC LOW TRACKING FROM OKLAHOMA TO NORTHERN INDIANA
WHICH IS FAVORABLE FOR WIDESPREAD PRECIP IN THE DVN CWA. WARMER AIR
ALOFT MAY MAKE IT FAR ENOUGH NORTH TO BRING VARYING PRECIP TYPES TO
PORTIONS OF THE FORECAST AREA. STAY TUNED. EARLY LOOK AT FORECAST
HIGHS ARE IN THE UPPER 20S TO MIDDLE 30S ON TUE.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 703 AM CST WED FEB 25 2015
12Z TAFS UPDATED FOR MINOR ADJUSTMENTS TO TIMING ON SNOW
ONSET...BETWEEN 15 AND 17Z THIS MORNING. EXPECTING LIFR CEILINGS
AND/OR VISIBILITIES WITH PERIOD OF MODERATE TO HEAVY SNOW. SNOW
WILL TAPER OFF FROM NW TO SE OVERNIGHT BUT IFR CEILINGS WILL
PERSIST THROUGH 12Z.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...WINTER WEATHER ADVISORY FROM NOON TODAY TO 6 AM CST THURSDAY FOR
CLINTON-DELAWARE-DUBUQUE-JACKSON-JONES-SCOTT.
WINTER STORM WARNING FROM NOON TODAY TO 6 AM CST THURSDAY FOR
CEDAR-DES MOINES-HENRY IA-JEFFERSON-LEE-LOUISA-MUSCATINE-
VAN BUREN.
WINTER STORM WARNING UNTIL 3 AM CST THURSDAY FOR BENTON-BUCHANAN-
IOWA-JOHNSON-KEOKUK-LINN-WASHINGTON.
IL...WINTER WEATHER ADVISORY FROM NOON TODAY TO 6 AM CST THURSDAY FOR
HENRY IL-MERCER-ROCK ISLAND.
WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 9 AM CST
THURSDAY FOR HANCOCK-HENDERSON-MCDONOUGH-WARREN.
MO...WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 9 AM CST
THURSDAY FOR CLARK-SCOTLAND.
&&
$$
SYNOPSIS...RP KINNEY
SHORT TERM...RP KINNEY
LONG TERM...UTTECH
AVIATION...RP KINNEY
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
403 AM CST WED FEB 25 2015
.SYNOPSIS...
ISSUED AT 330 AM CST WED FEB 25 2015
AT 330 AM...MID LEVEL CLOUDS WERE STREAMING INTO THE AREA AHEAD OF
A ROBUST CLIPPER SYSTEM. SNOW WAS CONTINUING TO DEVELOP ACROSS
PARTS OF SOUTH DAKOTA AND SOUTHWEST MINNESOTA. EARLY MORNING
TEMPERATURES WERE IN THE TEENS TO LOWER 20S AT MOST LOCATIONS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 330 AM CST WED FEB 25 2015
THE MAIN FORECAST ISSUE IS THE IMPENDING POTENT CLIPPER SYSTEM AND
ASSOCIATED SNOWFALL AMOUNTS AND COVERAGE.
LOOKING AT THE VARIOUS SYNOPTIC AND HIGH RES MODELS...LATEST
TRENDS HAVE BEEN TOWARD HIGHER SNOWFALL AMOUNTS AND A SLIGHTLY
FARTHER NORTH AXIS OF THE HEAVIEST SNOW. THE INITIAL ISSUE IS
TIMING OF THE ONSET OF SNOW...DEPENDENT ON HOW THE DEFORMATION
ZONE/DRY SLOT SET UP. THE WRF IS A BIT FASTER IN BRINGING SNOW
INTO THE WEST THIS MORNING...WHILE THE RAP HAS A MORE PRONOUNCED
DRY SLOT EARLY IN THE EVENT. FOR PURPOSES OF THE FORECAST GRIDS
AND HEADLINES...HAVE GONE WITH THE EARLIER TIMING...WHICH CAN BE
ADJUSTED THROUGH THE DAY.
GIVEN THE STRENGTH AND DEPTH OF THE FORCING THROUGH THE DENDRITIC
LAYER...THE HIGHER SNOWFALL AMOUNTS LOOK REASONABLE BASED ON
AVERAGE SNOW RATIOS THROUGH THE BULK OF THE EVENT IN THE 14-19:1
RANGE. ALSO FAVORED CONSENSUS QPF...WHICH IS SLIGHTLY HIGHER TO
THE NORTH THAN WPC VALUES. THE END RESULT IS ROUGHLY 6-9 INCHES
FROM INDEPENDENCE...TO WAPELLO...FORT MADISON AND POINTS EAST.
HAVE UPGRADED THESE AREAS TO A WINTER STORM WARNING. FROM
DUBUQUE...THROUGH THE QUAD CITIES...WEST CENTRAL ILLINOIS...AND
FAR NORTHEAST MISSOURI...EXPECTING GENERAL 3-6 INCH AMOUNTS WITH A
WINTER WEATHER ADVISORY IN EFFECT. LOCALLY ENHANCED HIGHER SNOWFALL
AMOUNTS ARE NOT OUT OF THE QUESTION IN THE ADVISORY AREA.
ADJUSTMENTS TO SNOWFALL AMOUNTS/HEADLINES ARE INEVITABLE AS WE
HEAD THROUGH THE DAY AND INTO THIS EVENING.
PEAK SNOWFALL INTENSITY EXPECTED IN THE AFTERNOON/EVENING...WHICH
WILL MAKE FOR A HAZARDOUS COMMUTE WITH SNOW COVERED ROADS AND
REDUCED VISIBILITY. A NORTHWEST WIND AROUND 15 MPH WITH HIGHER
GUSTS WILL LIKELY PRODUCE SOME SHALLOW DRIFTING SNOW AT TIMES. THE
SNOW WILL TAPER OFF FROM NORTHWEST TO SOUTHEAST LATE TONIGHT INTO
THURSDAY MORNING.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 330 AM CST WED FEB 25 2015
THURSDAY AND FRIDAY...VERY COLD PERIOD AS ARCTIC ~1042 MB HIGH
BUILDS INTO THE MIDWEST. FRESH POWDERY SNOW ON THE GROUND/LIGHT
WINDS (POSSIBLY DECOUPLED AT TIMES)/AND MAINLY CLEAR SKIES WILL SET
THE STAGE FOR VERY COLD OVERNIGHT LOWS. CURRENT FORECAST FAVORS THE
RAW GFS/ECMWF AS SUPERBLEND/NAM SEEM TO BE TOO WARM.
EXPECT WIDESPREAD LOWS BETWEEN -10 TO -15 F WHICH WOULD BE NEAR
RECORD TERRITORY FOR LATE FEBRUARY...SINGLE DIGIT SUB-ZERO LOWS ARE
MORE LIKELY SOUTH OF BURLINGTON. WINDS WILL REMAIN ON THE LIGHT SIDE
BUT EVEN AT 5-7 KTS THEY WILL BE ENOUGH TO CREATE DANGEROUS WIND
CHILLS BETWEEN -20 TO -30 F AT TIMES. VALUES NEAR -30 F SHOULD BE
RELATIVELY ISOLATED AND SHORT-LIVED. HIGHS ARE FORECAST TO BE IN THE
UPPER SINGLE DIGITS TO MID TEENS.
SATURDAY AND SUNDAY...SIGNIFICANT PATTERN CHANGE WILL OCCUR DURING
THIS TIME AS UPPER JET DIGS OUT A LARGE TROUGH OVER THE WESTERN U.S.
WHICH WILL CAUSE A BIG SHIFT IN THE ORIENTATION OF THE 850 MB
BAROCLINIC ZONE TO A SW-NE DIRECTION.
THERE HAS BEEN A CONSISTENT SIGNAL OF SIGNIFICANT LOW/MID LEVEL
MOISTURE ADVECTION FROM THE SW U.S. AND FROM THE GULF OF MEXICO FOR
SAT NIGHT INTO SUN. THEREFORE...A PERIOD OF SNOW IS LIKELY WITH
AMOUNTS UNCERTAIN THIS FAR OUT. WITH THE LACK OF A STRONG SHORTWAVE
TROUGH/VORTICITY MAX...MODELS DEVELOP LINEAR-LOOKING FRONTAL PRECIP
AND DO NOT DEVELOP A COHERENT SFC LOW WHICH WOULD PUT SOMEWHAT OF A
LIMIT ON THIS SYSTEM. DAYTIME TEMPS WILL BE IN THE 20S ON SAT AND
THE UPPER 20S TO LOWER 30S ON SUN.
MONDAY AND TUESDAY...CHANCE OF PRECIP MORE LIKELY LATER IN THE DAY
AND INTO TUE. MODELS STILL STRUGGLING WITH WHEN TO EJECT ORGANIZED
500 MB VORTICITY MAX OUT OF THE FOUR CORNERS AREA. THE GFS HAS A
WELL ORGANIZED SFC LOW TRACKING FROM OKLAHOMA TO NORTHERN INDIANA
WHICH IS FAVORABLE FOR WIDESPREAD PRECIP IN THE DVN CWA. WARMER AIR
ALOFT MAY MAKE IT FAR ENOUGH NORTH TO BRING VARYING PRECIP TYPES TO
PORTIONS OF THE FORECAST AREA. STAY TUNED. EARLY LOOK AT FORECAST
HIGHS ARE IN THE UPPER 20S TO MIDDLE 30S ON TUE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1138 PM CST TUE FEB 24 2015
A WINTER STORM SYSTEM DEVELOPING OVER THE NORTHERN PLAINS WILL
SPREAD SNOW ACROSS EASTERN IOWA AND NORTHWEST ILLINOIS WEDNESDAY
INTO WEDNESDAY NIGHT...RESULTING IN WIDESPREAD IFR TO LIFR
CONDITIONS. THROUGH THE REST OF TONIGHT INTO WEDNESDAY
MORNING...CONDITIONS WILL REMAIN VFR WITH LIGHT WINDS AND
INCREASING HIGH CLOUDS. SNOW AND LOWERING CIGS ARE EXPECTED TO
DEVELOP OVER CID BY MIDDAY AND REACH THE REST OF THE TERMINALS BY
MID AFTERNOON WITH WIDESPREAD IFR CONDITIONS BY LATE AFTERNOON.
ALL TERMINALS WILL HAVE THE POTENTIAL FOR LIFR OR EVEN VLIFR
PERIODS FROM LATE AFTERNOON INTO EARLY EVENING. WHILE NOT
ADVERTISED...SOME IMPROVEMENT IS POSSIBLE TOWARD LATE EVENING AT
CID AND DBQ AS THE SYSTEM BEGINS TO EXIT THE REGION.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...WINTER WEATHER ADVISORY FROM NOON TODAY TO 6 AM CST THURSDAY FOR
CLINTON-DELAWARE-DUBUQUE-JACKSON-JONES-SCOTT.
WINTER STORM WARNING FROM NOON TODAY TO 6 AM CST THURSDAY FOR
CEDAR-DES MOINES-HENRY IA-JEFFERSON-LEE-LOUISA-MUSCATINE-
VAN BUREN.
WINTER STORM WARNING FROM 9 AM THIS MORNING TO 3 AM CST THURSDAY
FOR BENTON-BUCHANAN-IOWA-JOHNSON-KEOKUK-LINN-WASHINGTON.
IL...WINTER WEATHER ADVISORY FROM NOON TODAY TO 6 AM CST THURSDAY FOR
HENRY IL-MERCER-ROCK ISLAND.
WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 9 AM CST
THURSDAY FOR HANCOCK-HENDERSON-MCDONOUGH-WARREN.
MO...WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 9 AM CST
THURSDAY FOR CLARK-SCOTLAND.
&&
$$
SYNOPSIS...RP KINNEY
SHORT TERM...RP KINNEY
LONG TERM...UTTECH
AVIATION...SHEETS
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
1007 PM EST THU FEB 26 2015
.UPDATE...
ISSUED AT 945 PM EST THU FEB 26 2015
A DISTURBANCE IS WORKING THROUGH THE GREAT LAKES AND OH VALLEY
REGION AND IS BRINGING SOME VERY LIGHT SNOW OR FLURRIES TO THE
REGION. AWOS AND ASOS SITES OVER CENTRAL AND NORTHERN KY HAVE
REPORTED SNOW REACHING THE GROUND...BUT THE AIRMASS IS RATHER
DRY...SO VISIBILITIES AND CEILINGS HAVE NOT DROPPED ALL THAT FAR.
AT THIS POINT...PER RADAR AND SFC OBS IT APPEARS THAT THE LIGHT
SNOW OR FLURRIES IS NEARING THE SOMERSET TO JACKSON TO SANDY HOOK
LINE. ONLY ONE KY MESONET SITE IN CENTRAL KY HAS RECEIVED
MEASURABLE PRECIPITATION WITH THIS.
THE NEAR TERM MODELS SUCH AS THE HRRR CONTINUE TO HAVE THIS
DIMINISHING AS IT MOVES EAST...BUT IT SEEMS TO CLEARLY BE HOLDING
TOGETHER BETTER THAN THE HRRR IS FORECASTING. THE WINDS ARE BIT
MORE NORTHERLY THAN IDEAL FOR UPSLOPE ALTHOUGH THERE IS A BIT OF
AN UPSLOPE COMPONENT. THE CURRENT FORECAST IS MORE REFLECTIVE OF
THE MOST RECENT NAM AND GFS RUNS AS SEEMS MORE REASONABLE GIVEN
UPSTREAM TRENDS. AT THIS POINT...SLIGHT CHANCE TO CHANCE POPS
APPEAR TO REMAIN IN ORDER AND AN SPS IS ALREADY IN PLACE. SOME
LOCATIONS MAY PICK UP A QUARTER TO A HALF OF AN INCH OF FLUFF
WHILE OTHER LOCATIONS MAY ONLY GET A LIGHT DUSTING OR NOTHING AT
ALL. THE BIGGER STORY WILL BE THE COLDER AIR WORKING INTO THE
REGION LATE TONIGHT. LOWS SHOULD REACH THE UPPER SINGLE DIGITS
ABOVE ZERO NORTH...WITH UPPER TEENS NEAR THE TN BORDER. TEMPS WILL
STRUGGLE TO REACH THE MID TO UPPER 20S IN MANY LOCATIONS ON
FRIDAY...ALTHOUGH FRI NIGHT APPEARS TO BE COLDER ON AVERAGE THAN
TONIGHT.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 355 PM EST THU FEB 26 2015
19Z SFC ANALYSIS SHOWS LOW PRESSURE PASSING BY TO THE EAST WHILE A
DEEP LOW IS APPROACHING FROM THE NORTHWEST. AN ARCTIC COLD FRONT
FROM THIS IS MOVING INTO KENTUCKY AND THIS WILL SWEEP ACROSS
EASTERN KENTUCKY LATER THIS EVENING. ON REGIONAL RADAR...THE LIGHT
SNOW ASSOCIATED WITH THIS BOUNDARY IS STARTING TO SETTLE DEEPER
INTO THE STATE. EAST KENTUCKY SAW PARTLY SUNNY SKIES THIS
AFTERNOON WITH SOME LOW CLOUDS CLINGING TO OUR FAR EASTERN AREAS
WHILE HIGH CLOUDS PASSED THROUGH NORTHERN PARTS OF THE CWA. LOWER
CLOUDS ARE INBOUND FROM WESTERN AND CENTRAL KENTUCKY NOW...AHEAD
OF THAT FRONT. TEMPERATURES WERE ABLE TO SPIKE UP TO NEAR 40
DEGREES FOR MUCH OF THE AREA THIS AFTERNOON THANKS TO THE PARTIAL
SUNSHINE WHILE ONLY LOW 30S WERE ACHIEVED IN THE NORTHWEST.
DEWPOINTS REMAIN IN THE TEENS IN THE NORTHWEST WHILE LOWER AND
MIDDLE 20S ARE FOUND IN THE EAST. WINDS WERE GENERALLY FROM THE
NORTHWEST AT 5 TO 10 MPH WITH GUSTS TO 15 MPH.
THE MODELS ARE IN GOOD AGREEMENT ALOFT AS A WEAK WAVE PASSES TO
THE SOUTH OF THE AREA THIS EVENING FOLLOWED BY A STRONGER AND
LARGER TROUGH THAT SETTLES INTO THE OHIO VALLEY TONIGHT. THIS
TROUGH WILL BRING ITS CORE ENERGY ACROSS OHIO DURING THE DAY
FRIDAY BEFORE TAPERING OFF AMIDST REBOUNDING HEIGHTS OVER KENTUCKY
FRIDAY NIGHT. THE ECMWF IS A BIT QUICKER THAN THE OTHER MODELS
WITH THESE HEIGHT RISES AND MAY BE GETTING AHEAD OF ITSELF. GIVEN
THE GENERAL AGREEMENT...AT LEAST INTO FRIDAY EVENING...HAVE
FAVORED THE HIGHER RESOLUTION MODEL GUIDANCE FROM THE HRRR...
RAP13...AND NAM12 FOR WX SPECIFICS.
SENSIBLE WEATHER WILL FEATURE CLOUDS ARRIVING ALONG WITH SNOW
SHOWERS THIS EVENING AND CONTINUING THROUGH THE NIGHT IN
ASSOCIATION WITH THE ARCTIC AIR POURING BACK INTO THIS PART OF THE
STATE. TEMPERATURES WILL FALL INTO THE TEENS IN MOST PLACES BY
DAWN THANKS TO THE CAA WITH SOME SINGLE DIGITS POSSIBLE NORTH OF
INTERSTATE 64. ANY LINGERING SNOW SHOWERS WILL COME TO AN END
FRIDAY MORNING IN FAR EASTERN PARTS OF THE AREA WITH SOME SUNSHINE
POSSIBLE BY AFTERNOON...BUT TEMPERATURES WILL STILL STRUGGLE TO
MAKE IT INTO THE LOWER 20S BY MIDDAY. THIS SETS THE STAGE FOR A
VERY CHILLY NIGHT WITH SINGLE DIGITS LIKELY ON TAP FOR THE VALLEYS
AND MORE OPEN AREAS...WHILE SOME LATE ARRIVING HIGH CLOUDS AND THE
INVERSION MAY SPARE THE RIDGES THE COLDEST OF THE AIR. CANNOT RULE
OUT SOME FLURRIES ARRIVING TOWARD DAWN SATURDAY AHEAD OF THE NEXT
SYSTEM...BUT HAVE LEFT THEM OUT FOR NOW.
AGAIN USED THE CONSSHORT TO JUMP START THE T/TD/WIND GRIDS
THROUGH THE DAY FRIDAY...WITH SOME TERRAIN BASED ADJUSTMENTS MADE
AT NIGHT. AFTER THAT...USED THE SUPERBLEND TO INITIATE THE GRIDS
INTO SATURDAY MORNING WITH MINOR CHANGES. AS FOR POPS...ENDED UP
ON THE HIGH SIDE...CLOSER TO THE MET...OF RATHER LOW MOS GUIDANCE
TONIGHT...THEN SIMILAR FOR THE REST OF THE SHORT TERM.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 400 PM EST THU FEB 26 2015
BROAD MID AND UPPER LEVEL TROUGH ACROSS THE ENTIRE CONUS WILL DEEPEN
OVER THE FAR SOUTHWEST...BAJA THROUGH THE WEEKEND PLACING OUR AREA
IN A GENERAL SOUTHWEST FLOW REGIME FOR THE BULK OF THE EXTENDED.
THIS WILL TEND TO KEEP STORM TRACKS SOMEWHAT CENTERED OVER THE OHIO
VALLEY REGION AS A SERIES OF DISTURBANCES RIDE NORTHEAST ACROSS THE
EASTERN CONUS. OVERALL IT APPEARS WE WILL BE GETTING INTO A VERY
ACTIVE WEATHER PATTERN...TYPICAL FOR THE APPROACH OF EARLY SPRING.
ACTUAL SENSIBLE WEATHER...PRECIPITATION TYPES...AMOUNTS ETC. WILL
DEPEND MORE ON EXACT TRACK OF SURFACE LOWS THROUGH THE REGION.
CONSIDERING THE CURRENT SNOWPACK ALONG WITH THE WATER CONTENT
PRESENT ACROSS A LARGE PART OF THE AREA...POTENTIAL HYDRO ISSUES
WILL NEED TO BE CONSIDERED SHOULD MUCH OF ANY PRECIPITATION WE
REALIZE THROUGH THE PERIOD FALL IN THE FORM OF RAIN.
MODEL SOLUTIONS APPEAR TO BE IN FAIRLY GOOD AGREEMENT THROUGH THE
EXTENDED. A SERIES OF STORM SYSTEMS SHOOT OUT OF THE INTER-MOUNTAIN/
SOUTH CENTRAL PLAINS AREA IN RAPID FIRE FASHION THROUGH THE PERIOD.
THE FIRST SHOULD AFFECT OUR AREA SUNDAY INTO MONDAY...THE SECOND
TUESDAY THROUGH EARLY WEDNESDAY AND THEN THE THIRD LATE WEDNESDAY
NIGHT INTO THURSDAY. ATTM MODEL CONSENSUS IS FOR SFC LOWS TO TRACK
GENERALLY TO OUR NORTHWEST...KEEPING OUR AREA IN THE WARM SECTORS OF
THESE SYSTEMS. HOWEVER...THE COLDER AIR THAT FILTERS IN BEHIND EACH
PASSING SYSTEM MAY ALLOW FOR THE A WINTRY MIX AT THE ONSET OF EACH
NEW ROUND OF WEATHER. THIS MAY BE ESPECIALLY TRUE NEXT TUESDAY
MORNING. AFTER A VERY COLD START FOR FRIDAY...EXPECT TEMPERATURES TO
GRADUALLY MODERATE TOWARDS MORE NORMAL LEVELS THROUGH THE EXTENDED
THOUGH OVERALL WE WILL REMAIN BELOW NORMS FOR THIS TIME OF THE
YEAR.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 740 PM EST THU FEB 26 2015
A GRADUAL DETERIORATION TO MVFR...AT LEAST BRIEFLY...IS POSSIBLE
AS SOME LIGHT SNOW OR FLURRIES WORKS ACROSS THE AREA THIS EVENING
AND INTO THE OVERNIGHT HOURS. LAMP DATA POINTS TOWARD CONTINUED
MVFR WELL INTO THE DAY ON FRI...PAST 12Z...BUT UPSTREAM OBS BEHIND
THE AREA OF LIGHT SNOW ARE IN THE VFR RANGE. CONFIDENCE IN A
PROLONGED PERIOD OF MVFR IS NOT HIGH...BUT KEPT PERSISTENCE FROM
THE PREVIOUS FORECAST BEYOND THE FIRST 6 TO 8 HOURS WHICH WAS IN
LINE WITH THE LAMP. WINDS WILL BE GENERALLY OUT OF THE NORTH TO
NORTHWEST THROUGH THE PERIOD AT 5 TO 10 KT.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JP
SHORT TERM...GREIF
LONG TERM...SBH
AVIATION...JP
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
205 PM EST WED FEB 25 2015
.UPDATE...
ISSUED AT 205 PM EST WED FEB 25 2015
DID A QUICK UPDATE TO FINE TUNE TEMPERATURES AND SKY COVER THROUGH
THE REST OF THE DAY WITH THE SNOW SLATED TO MOVE IN AROUND 00Z IN
OUR SOUTHERN COUNTIES...BUT QUICKLY SPREADING NORTH AND EAST INTO
THE EVENING HOURS...MAINLY JUST AFFECTING THE ADVISORY AREAS. THE
UPDATED GRIDS HAVE BEEN SENT TO THE NDFD AND WEB SERVERS.
UPDATE ISSUED AT 1125 AM EST WED FEB 25 2015
15Z SFC ANALYSIS SHOWS A WEAK AREA OF HIGH PRESSURE RETREATING OFF
TO THE EAST AHEAD OF A PAIR OF APPROACHING LOW PRESSURE SYSTEMS.
THE MAIN ONE OF CONCERN WILL BE ONE COMING OUT OF THE NORTHERN
GULF WITH A WELL DEFINED COMMA HEAD OF PRECIPITATION. HIGH CLOUDS
AHEAD OF THIS LOW HAVE OVERSPREAD THE AREA LIKELY CAPPING OUR
TEMPERATURE CLIMB THIS AFTERNOON. READINGS ARE IN THE UPPER 20S
AND LOW 30S THROUGH EASTERN KENTUCKY WITH DEWPOINTS HOLDING IN THE
MID TEENS WHILE THE WINDS ARE LIGHT AND VARIABLE. THE FORECAST IS
ON TRACK FOR THE REST OF THE DAY AS THE SNOW APPROACHES FROM THE
SOUTH. THE LATEST HRRR HOLDS OFF ON ITS ARRIVAL INTO KENTUCKY
UNTIL AFTER 00Z STILL TARGETING THE FAR SOUTHEAST FOR ANY DECENT
ACCUMULATIONS. UPDATED GRIDS HAVE BEEN SENT TO THE NDFD AND WEB
SERVERS...ALONG WITH A FRESHENED SET OF ZONES.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 421 AM EST WED FEB 25 2015
CURRENT CONDITIONS ACROSS THE AREA AS OF 09Z FEATURE JUST SOME LOW
LEVEL CLOUD COVER TRACKING OVER EASTERN KENTUCKY FROM THE
NORTHWEST AS A WEAK TROUGH IS MOVING THROUGH. THIS FEATURES WILL
LIKELY THROW A FEW FLURRIES ACROSS SOME LOCATIONS THIS MORNING
BEFORE HEADING OFF TO THE EAST. THE CLOUD COVER MOVING OVER THE
AREA HAS REALLY KEPT OUR LOW TEMPERATURES UP FOR MINS THIS
MORNING. AT THIS TIME...A DEVELOPING SYSTEM BEGINS TO TAKE SHAPE
OVER THE LOWER MS RIVER VALLEY AND WILL TRACK NORTHEAST TODAY.
SHORT TERM MODELS HAVE COME INTO DECENT AGREEMENT WITH THIS
FEATURE AS A STRONG SHORTWAVE WILL BE ASSOCIATED WITH SURFACE LOW
PRESSURE DEVELOPING AND MOVING EAST INTO THE LOWER TN VALLEYS AND
APPALACHIANS BY 00Z TONIGHT.
THE PREVIOUS RUNS HAVE TRENDED THIS FEATURE NORTH FAR ENOUGH TO
BRING A DECENT SHOT OF ACCUMULATING SNOWFALL TO SOUTHERN AND
SOUTHEASTERN EAST KENTUCKY. MODEL PROFILES DO SHOW A DECENT DRY
AIR LAYER TO OVERCOME BUT AS EXPERIENCED IN THE PREVIOUS EVENT IN
THE SOUTHERN STREAM...THE LAYER CAN BE OVERCOME QUITE EFFECTIVELY
WITH THE AMOUNT OF GULF MOISTURE THIS SYSTEM WILL BE TAPPING INTO.
AS WELL THE SOUTHERN AND EASTERN COUNTIES THROUGH THIS EVENT WILL
HAVE A SATURATED LAYER IN THE -10 TO -20 CELSIUS ZONE FOR A GOOD
PORTION OF THIS EVENT. THE CLOUD COVER HANGING AROUND EARLIER IN
THE DAY THAT KEPT TEMPS WARM MAY HAVE AN EFFECT ON AMOUNTS FROM
THE EVENT TONIGHT BUT DIURNAL TRENDS AND NORTHEAST LOW LEVEL FLOW
SHOULD BE COLD ENOUGH FOR SNOW AT ONSET. THEREFORE...WITH THESE
FACTORS...HAVE GONE WITH 10 OR 12 TO 1 SNOW RATIOS IN THE SOUTH
AND THEN GOING HIGHER IN THE NORTHWEST TOWARDS THE COLDER AIR.
THIS WILL GIVE SNOW AMOUNTS IN THE 1 TO 2 INCH RANGE WITH UP TO 3
INCHES IN THE HIGHER ELEVATIONS. WENT WITH AN WINTER WEATHER
ADVISORY FOR THIS AND WILL PUT AN SPS OUT FOR THE NORTHERN
COUNTIES AS SOME OF THOSE AREAS MAY AT LEAST GET UP TO AN
INCH...ESPECIALLY WITH THE HIGHER RATIOS.
HEADING INTO THE DAY ON THURSDAY...THE SYSTEM MOVES OFF TO THE
EAST AS ANOTHER ARCTIC FRONT MOVES IN BEHIND THE SYSTEM. THIS
PATTERN WILL ONCE AGAIN FAVOR AN UPSLOPE EVENT FOR SNOW SHOWERS
BUT NOT ANTICIPATING SIGNIFICANT ACCUMULATIONS FROM THIS AS
PROFILES SEEM TO BE TOO DRY BUT ALSO LACKING IN ANY SIGNIFICANT
INSTABILITY. KEPT AMOUNTS FOR THIS THROUGH THE DAY UNDER AN INCH
WITH HIGH RATIOS.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 427 AM EST WED FEB 25 2015
THE SOUTHERN STREAM SHORTWAVE AND ASSOCIATED SURFACE LOW WILL BE
WELL NE TO START THE PERIOD. THE NORTHERN STREAM DISTURBANCE WILL
KEEP CHANCE POPS ESPECIALLY ACROSS THE FAR SE OVERNIGHT BEFORE
EXIT THE REGION MOVING INTO FRIDAY. UPPER LEVELS WILL GRADUALLY
TRANSITION TO ZONAL FLOW. SURFACE HIGH PRESSURE ACROSS THE PLAINS
WILL THEN GRADUALLY BUILD EAST ACROSS THE OHIO AND TENNESSEE
VALLEYS. THIS WILL ONCE AGAIN USHER IN WELL BELOW NORMAL TEMPS
ACROSS THE REGION WITH LOWS DROPPING INTO THE SINGLE DIGITS AND
TEENS THUR AND FRI NIGHT AND HIGHS FRI IN THE 20S. THIS HIGH
PRESSURE WILL BE FAIRLY TRANSIENT WITH A BIT OF RETURN FLOW AS WE
MOVE INTO SATURDAY UNDER PARTLY CLOUDY SKIES WITH INCREASING
CLOUDS TOWARD EVENING. HIGHS ON SATURDAY BOUNCE BACK INTO THE LOW
TO MID 30 NORTH AND AND MID TO UPPER 30S SOUTH. THIS HIGH PRESSURE
WILL CONTINUE MOVING EAST ACROSS THE MID ATLANTIC OVERNIGHT
SATURDAY. THEN EYES WILL TURN TO OVERRUNNING EVENT FOR THE FIRST
PART OF NEXT WEEK. INITIALLY THIS WILL BRING INCREASE IN CLOUDS ON
SATURDAY NIGHT INTO SUNDAY. INCREASE IN POPS WILL ALSO BEGIN
PARTICULARLY SUNDAY AFTERNOON. THERE ARE REMAINS A FAIR AMOUNT OF
UNCERTAINTIES AROUND EXACT AMTS AND TRACK OF THIS OVERRUNNING
PORTION OF THE SYSTEM. THEN LATE IN THE PERIOD FOCUS SHIFTS TO THE
UPPER LEVEL TROUGH ACROSS THE SW US STRENGTHENING AND EJECTING NE.
THIS WILL BRING SURFACE LOW ACROSS THE MIDWEST INTO THE OHIO
VALLEY BY TUESDAY OR WEDNESDAY. THE GFS AND ECMWF MODELS DISAGREE
ON TIMING OF THIS SURFACE LOW WITH GFS MOST PROGRESSIVE AND RIGHT
NOW BLEND BRINGS BEST POPS FOR TUESDAY. EITHER WAY GIVEN
SUBSTANTIAL FETCH OF MOISTURE WITH PWATS AT OR ABOVE 1 INCH AND
EVEN A CONVECTIVE ELEMENT WITH THE FRONT/NEGATIVELY TILTED
TROUGH...THIS WILL POSE A FLOODING THREAT ESPECIALLY IN AREAS THAT
STILL HAVE A SUBSTANTIAL SNOW PACK. FUTURE SHIFTS WILL HAVE TO
CONTINUE TO MONITOR THE POTENTIAL FOR FLOODING ISSUES AND FLOODING
PRODUCTS WILL POSSIBLY NEED TO BE ISSUED FOR THIS WARMUP AND
PRECIP EVENT AS WE MOVE INTO THE WEEKEND.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 130 PM EST WED FEB 25 2015
EXPECT VFR CONDITIONS TO CONTINUE THROUGH THE FIRST PART OF THE
TAF PERIOD. LOOK FOR HIGH CIGS TO DROP TO AROUND 4K FEET BY 02Z IN
THE SOUTH AND BY 04Z NORTH WITH SOME IFR OR LOWER CIGS AND VIS
ANTICIPATED TOWARD MIDNIGHT ACROSS THE SOUTHERN TIER OF THE
FORECAST AREA. THESE LOWER CIGS WILL ACCOMPANY THE NORTHERN FRINGE
OF A SIGNIFICANT WINTER STORM SYSTEM PASSING THROUGH THE
SOUTHEAST PARTS OF THE NATION BRINGING A PERIOD OF SNOW TO THE
AREA. THE HEAVIEST AND HARDEST OF THE SNOW WILL FALL SOUTHEAST OF
OF MAIN TAF SITES. THE SNOW WILL TAPER OFF AND CIGS WILL START TO
IMPROVE INTO THE DAY ON THURSDAY. WINDS WILL BE LIGHT AND VARIABLE
THROUGH LATE EVENING FOR MOST PLACES BEFORE SWITCHING TO THE
NORTHEAST AND NORTH AT BETWEEN 5 AND 10 KTS THROUGH THE DAY
THURSDAY.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 5 PM THIS AFTERNOON TO 7 AM EST
THURSDAY FOR KYZ079-080-083>088-110-113-115>118-120.
&&
$$
UPDATE...GREIF
SHORT TERM...SHALLENBERGER
LONG TERM...DJ
AVIATION...GREIF
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
1125 AM EST WED FEB 25 2015
.UPDATE...
ISSUED AT 1125 AM EST WED FEB 25 2015
15Z SFC ANALYSIS SHOWS A WEAK AREA OF HIGH PRESSURE RETREATING OFF
TO THE EAST AHEAD OF A PAIR OF APPROACHING LOW PRESSURE SYSTEMS.
THE MAIN ONE OF CONCERN WILL BE ONE COMING OUT OF THE NORTHERN
GULF WITH A WELL DEFINED COMMA HEAD OF PRECIPITATION. HIGH CLOUDS
AHEAD OF THIS LOW HAVE OVERSPREAD THE AREA LIKELY CAPPING OUR
TEMPERATURE CLIMB THIS AFTERNOON. READINGS ARE IN THE UPPER 20S
AND LOW 30S THROUGH EASTERN KENTUCKY WITH DEWPOINTS HOLDING IN THE
MID TEENS WHILE THE WINDS ARE LIGHT AND VARIABLE. THE FORECAST IS
ON TRACK FOR THE REST OF THE DAY AS THE SNOW APPROACHES FROM THE
SOUTH. THE LATEST HRRR HOLDS OFF ON ITS ARRIVAL INTO KENTUCKY
UNTIL AFTER 00Z STILL TARGETING THE FAR SOUTHEAST FOR ANY DECENT
ACCUMULATIONS. UPDATED GRIDS HAVE BEEN SENT TO THE NDFD AND WEB
SERVERS...ALONG WITH A FRESHENED SET OF ZONES.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 421 AM EST WED FEB 25 2015
CURRENT CONDITIONS ACROSS THE AREA AS OF 09Z FEATURE JUST SOME LOW
LEVEL CLOUD COVER TRACKING OVER EASTERN KENTUCKY FROM THE
NORTHWEST AS A WEAK TROUGH IS MOVING THROUGH. THIS FEATURES WILL
LIKELY THROW A FEW FLURRIES ACROSS SOME LOCATIONS THIS MORNING
BEFORE HEADING OFF TO THE EAST. THE CLOUD COVER MOVING OVER THE
AREA HAS REALLY KEPT OUR LOW TEMPERATURES UP FOR MINS THIS
MORNING. AT THIS TIME...A DEVELOPING SYSTEM BEGINS TO TAKE SHAPE
OVER THE LOWER MS RIVER VALLEY AND WILL TRACK NORTHEAST TODAY.
SHORT TERM MODELS HAVE COME INTO DECENT AGREEMENT WITH THIS
FEATURE AS A STRONG SHORTWAVE WILL BE ASSOCIATED WITH SURFACE LOW
PRESSURE DEVELOPING AND MOVING EAST INTO THE LOWER TN VALLEYS AND
APPALACHIANS BY 00Z TONIGHT.
THE PREVIOUS RUNS HAVE TRENDED THIS FEATURE NORTH FAR ENOUGH TO
BRING A DECENT SHOT OF ACCUMULATING SNOWFALL TO SOUTHERN AND
SOUTHEASTERN EAST KENTUCKY. MODEL PROFILES DO SHOW A DECENT DRY
AIR LAYER TO OVERCOME BUT AS EXPERIENCED IN THE PREVIOUS EVENT IN
THE SOUTHERN STREAM...THE LAYER CAN BE OVERCOME QUITE EFFECTIVELY
WITH THE AMOUNT OF GULF MOISTURE THIS SYSTEM WILL BE TAPPING INTO.
AS WELL THE SOUTHERN AND EASTERN COUNTIES THROUGH THIS EVENT WILL
HAVE A SATURATED LAYER IN THE -10 TO -20 CELSIUS ZONE FOR A GOOD
PORTION OF THIS EVENT. THE CLOUD COVER HANGING AROUND EARLIER IN
THE DAY THAT KEPT TEMPS WARM MAY HAVE AN EFFECT ON AMOUNTS FROM
THE EVENT TONIGHT BUT DIURNAL TRENDS AND NORTHEAST LOW LEVEL FLOW
SHOULD BE COLD ENOUGH FOR SNOW AT ONSET. THEREFORE...WITH THESE
FACTORS...HAVE GONE WITH 10 OR 12 TO 1 SNOW RATIOS IN THE SOUTH
AND THEN GOING HIGHER IN THE NORTHWEST TOWARDS THE COLDER AIR.
THIS WILL GIVE SNOW AMOUNTS IN THE 1 TO 2 INCH RANGE WITH UP TO 3
INCHES IN THE HIGHER ELEVATIONS. WENT WITH AN WINTER WEATHER
ADVISORY FOR THIS AND WILL PUT AN SPS OUT FOR THE NORTHERN
COUNTIES AS SOME OF THOSE AREAS MAY AT LEAST GET UP TO AN
INCH...ESPECIALLY WITH THE HIGHER RATIOS.
HEADING INTO THE DAY ON THURSDAY...THE SYSTEM MOVES OFF TO THE
EAST AS ANOTHER ARCTIC FRONT MOVES IN BEHIND THE SYSTEM. THIS
PATTERN WILL ONCE AGAIN FAVOR AN UPSLOPE EVENT FOR SNOW SHOWERS
BUT NOT ANTICIPATING SIGNIFICANT ACCUMULATIONS FROM THIS AS
PROFILES SEEM TO BE TOO DRY BUT ALSO LACKING IN ANY SIGNIFICANT
INSTABILITY. KEPT AMOUNTS FOR THIS THROUGH THE DAY UNDER AN INCH
WITH HIGH RATIOS.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 427 AM EST WED FEB 25 2015
THE SOUTHERN STREAM SHORTWAVE AND ASSOCIATED SURFACE LOW WILL BE
WELL NE TO START THE PERIOD. THE NORTHERN STREAM DISTURBANCE WILL
KEEP CHANCE POPS ESPECIALLY ACROSS THE FAR SE OVERNIGHT BEFORE
EXIT THE REGION MOVING INTO FRIDAY. UPPER LEVELS WILL GRADUALLY
TRANSITION TO ZONAL FLOW. SURFACE HIGH PRESSURE ACROSS THE PLAINS
WILL THEN GRADUALLY BUILD EAST ACROSS THE OHIO AND TENNESSEE
VALLEYS. THIS WILL ONCE AGAIN USHER IN WELL BELOW NORMAL TEMPS
ACROSS THE REGION WITH LOWS DROPPING INTO THE SINGLE DIGITS AND
TEENS THUR AND FRI NIGHT AND HIGHS FRI IN THE 20S. THIS HIGH
PRESSURE WILL BE FAIRLY TRANSIENT WITH A BIT OF RETURN FLOW AS WE
MOVE INTO SATURDAY UNDER PARTLY CLOUDY SKIES WITH INCREASING
CLOUDS TOWARD EVENING. HIGHS ON SATURDAY BOUNCE BACK INTO THE LOW
TO MID 30 NORTH AND AND MID TO UPPER 30S SOUTH. THIS HIGH PRESSURE
WILL CONTINUE MOVING EAST ACROSS THE MID ATLANTIC OVERNIGHT
SATURDAY. THEN EYES WILL TURN TO OVERRUNNING EVENT FOR THE FIRST
PART OF NEXT WEEK. INITIALLY THIS WILL BRING INCREASE IN CLOUDS ON
SATURDAY NIGHT INTO SUNDAY. INCREASE IN POPS WILL ALSO BEGIN
PARTICULARLY SUNDAY AFTERNOON. THERE ARE REMAINS A FAIR AMOUNT OF
UNCERTAINTIES AROUND EXACT AMTS AND TRACK OF THIS OVERRUNNING
PORTION OF THE SYSTEM. THEN LATE IN THE PERIOD FOCUS SHIFTS TO THE
UPPER LEVEL TROUGH ACROSS THE SW US STRENGTHENING AND EJECTING NE.
THIS WILL BRING SURFACE LOW ACROSS THE MIDWEST INTO THE OHIO
VALLEY BY TUESDAY OR WEDNESDAY. THE GFS AND ECMWF MODELS DISAGREE
ON TIMING OF THIS SURFACE LOW WITH GFS MOST PROGRESSIVE AND RIGHT
NOW BLEND BRINGS BEST POPS FOR TUESDAY. EITHER WAY GIVEN
SUBSTANTIAL FETCH OF MOISTURE WITH PWATS AT OR ABOVE 1 INCH AND
EVEN A CONVECTIVE ELEMENT WITH THE FRONT/NEGATIVELY TILTED
TROUGH...THIS WILL POSE A FLOODING THREAT ESPECIALLY IN AREAS THAT
STILL HAVE A SUBSTANTIAL SNOW PACK. FUTURE SHIFTS WILL HAVE TO
CONTINUE TO MONITOR THE POTENTIAL FOR FLOODING ISSUES AND FLOODING
PRODUCTS WILL POSSIBLY NEED TO BE ISSUED FOR THIS WARMUP AND
PRECIP EVENT AS WE MOVE INTO THE WEEKEND.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 644 AM EST WED FEB 25 2015
EXPECT VFR CONDITIONS THROUGH MUCH OF THE TAF PERIOD. THERE IS A
WEAK FRONT MOVING THROUGH THE AREA THIS MORNING AND THERE MAY BE
A FEW LOCATIONS AFTER DAWN WHERE A 3 KFT CIG POPS UP BUT
OVERALL...CIGS WILL BE AROUND 4 KFT. THROUGH THE DAY...WINDS WILL
BE LIGHT AND VARIABLE WITH CLOUD COVER INCREASING TOWARDS THE END
OF THE TAF PERIOD. SOME IFR CEILINGS WILL MOVE IN AFTER 00Z INTO
THE LOZ...SME...AND JKL...THEN LOCATIONS NORTH...AS THE NEXT
SYSTEM MOVES IN. SOME LIGHT SNOW WILL DEVELOP INTO THESE AREAS
AFTER 03Z TONIGHT. BY 06Z TONIGHT AND TILL THE END OF THE
PERIOD...BELOW FIELD MINS IN VIS AND CIGS WILL SET IN AS THE MORE
MODERATE SNOW MOVES IN.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 5 PM THIS AFTERNOON TO 7 AM EST
THURSDAY FOR KYZ079-080-083>088-110-113-115>118-120.
&&
$$
UPDATE...GREIF
SHORT TERM...SHALLENBERGER
LONG TERM...DJ
AVIATION...SHALLENBERGER
AREA FORECAST DISCUSSION
NWS GRAY ME
1207 AM EST WED FEB 25 2015
.SYNOPSIS...
WEAK LOW PRESSURE WILL PASS EAST OF THE AREA LATE TONIGHT AND
WEDNESDAY....AND WILL PRODUCE A PERIOD OF SNOW...ENDING BY
WEDNESDAY AFTERNOON. HIGH PRESSURE FOLLOWS THIS SYSTEM FOR
THURSDAY INTO THE START OF NEXT WEEKEND. THE NEXT CHANCE FOR
PRECIPITATION WILL COME AS HIGH PRESSURE RETREATS LATE IN THE
WEEKEND OR EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
1205 AM...MINOR ESTF UPDATE TO INGEST THE LATEST MESONET INTO 1ST
PERIOD GRIDS.
PREV DISC...
1040 PM UPDATE...VERY LITTLE CHANGE TO THE GOING FORECAST.
TIGHTENED UP THE EXPECTED SNOWFALL GRADIENT FOR THE OVERNIGHT. THIS
BASED ON LATEST FEW RUNS OF THE HRRR...RAP...AND 00Z NAM GUIDANCE
AS WELL AS REGIONAL RADAR IMAGERY. BUT I ADMIT IT IS GOING TO BE A
CLOSE CALL. ALMOST CERTAINLY A CASE OF THE HAVES AND HAVE NOTS
GIVEN THE EXPECTED SNOWFALL GRADIENT BASED ON LATEST RADAR IMAGERY
IN THE VICINITY OF EASTERN LONG ISLAND. RADAR WATCHING ACROSS
RI/SE MASS OVER THE COURSE OF THE NEXT TWO HOURS WILL BE THE KEY
TO UPDATING POPS/AMTS ASSOCIATED WITH THE WESTERN EDGE OF THE
SNOW SHIELD. WHOMEVER GETS IN IN IT MAY SNOW HEAVILY FOR AN HOUR
OR TWO...WITH GOOD ACCUMULATORS AS FAR AS SNOWFLAKE TYPES GO. WE
MAINLY EXPECT THIS POSSIBILITY NEAR AND EAST OF I-95.
930 PM UPDATE...NO CHANGES TO THE FORECAST AT THIS TIME.
AWAITING THE ARRIVAL OF THE 00Z RGEM AND NEW HRRR/RAP RUNS BEFORE
MAKING ANY CHANGES THE FORECAST THIS EVENING. WHILE RAPID UPDATE
MESOSCALE GUIDANCE LIKE THE HRRR AND RAP ARE STILL EAST WITH ANY
SNOWFALL...THE RADAR IMAGERY SOUTH OF LONG ISLAND NY SAYS PERHAPS
OTHERWISE. STILL EXPECTING THE MID COAST OF MAINE TO DO PRETTY
WELL OVERNIGHT...JUST NOT COMPLETELY SURE IF ACCUMULATING SNOW
MAKES AN APPRARANCE IN PSM AND PWM FOR EXAMPLE.
615 PM UPDATE...HAVE UPDATED THE NEAR TERM FORECAST BASED ON
LATEST TRENDS IN OBSERVATIONAL DATA AS WELL AS NEW MESOSCALE
MODEL DATA. IT WILL BE INTERESTING TO SEE HOW THE SNOWFALL PANS
OUT LATER TONIGHT. 18Z MODEL RUNS PRETTY MUCH STATUS QUO.
HOWEVER...LATEST FEW RUNS OF THE RAP AND HRRR KEEP MOST OF IT
OFFSHORE. HOPEFULLY THE TWO CAMPS WILL MERGE OVER THE NEXT COUPLE
OF HOURS.
PREVIOUSLY...
WEAK WAVES IN THE SRN AND NRN STREAM PASS TO OUR NW AND SE LATE
TONIGHT /BEFORE EVENTUALLY PHASING TO OUR EAST ON WED/ AND WILL
BRING A PERIOD OF LIGHT OR SHSN TO MOVE OVER THE REGION...MAINLY
AFTER MIDNIGHT. MODELS ARE IN GOOD AGREEMENT THAT AS THE SYSTEMS
INTERACT LATE TONIGHT WE WILL START TO SEE SOME MID LVL
FRONTOGENESIS FORM JUST OFFSHORE. THIS WILL LKLY FORM A BAND OF SNOW
OFF THE COAST...WHICH WILL GRAZE COASTAL AREAS E OF KPWM AND WILL
IMPACT THE MID COAST AND ESPECIALLY THE PENOBSCOT BAY REGION WITH 3
TO 6 INCHES OF SNOW. AS YOU MOVE FURTHER NW FROM THIS AREA AMTS DROP
OFF QUICKLY...WITH 1-3" FROM SEACOAST NH NE THROUGH THE PORTLAND
AREA...THE CAPITAL REGION...AND INTO SRN SOMERSET COUNTY. EXPECT AN
INCH OR LESS ACROSS THE REST OF NH AND INTERIOR WRN ME. THE BULK OF
THE SNOW LOOKS TO FALL BETWEEN 06Z AND 12Z. IN THE ADVISORY AREA IT
MAY LINGER UNTIL ABOUT 15Z...SO COULD SEE A QUICK 4-6" OF SNOW HERE
DURING PRE-DAWN AND INTO THE MORNING COMMUTE. TEMPS WILL DROP OFF A
BIT THIS EVENING...MORE SO IN THE ERN AND NRN ZONES WHERE LESS
CLOUDS AND A PERIOD WITHOUT ANY REAL BL FLOW WILL ALLOW SOME RAD
COOLING. BUT TEMPS HERE WILL STALL AND SHOULD BEGIN TO RISE NEAR THE
COAST AFTER MIDNIGHT.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM THURSDAY/...
SOME LIGHT SNOW MAY LINGER OUTSIDE THE ADV AREA FOR THE EARLY
MORNING...BUT SHOULD BE CLOSE TO OVER BY 12Z...WITH THE EXCEPTION
OF THE ADVISED MID-COAST AREA...WHERE SNOW WILL LINGER THRU ABOUT
14-15Z. MODELS INDICATE RAPID CLEARING FROM W-E BEHIND THIS SYSTEM
AS W WINDS DOWNSLOPE AND DRIER AIR MOVES IN. WITH THE SUN AND THE
DOWNSLOPE...WILL SEE TEMPS RISE IN THE UPPER 20S TO LOWER 30S ON THE
COASTAL...AND INTO THE LOW TO MID 20S IN THE MTNS AND FOOTHILLS.
THE WINDS DIE OFF AROUND SUNSET WITH MAINLY CLEAR SKIES AND LIGHT
WINDS SHOULD SEE SOME GOOD RAD COOLING...BUT WITH WARMER AIR
ALOFT...WILL NOT BE AS COLD AS MON MORNING WITH LOWS SINGLE ABV ZERO
NEAR THE COAST...AND SINGLE DIGITS BELOW ZERO INLAND.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
LOW PRESSURE WILL MOVE
SOUTH OF THE REGION DURING THURSDAY. AT THIS POINT IT LOOKS LIKE
CLOUDS FROM THIS SYSTEM WILL CROSS THE AREA BUT THE PRECIPITATION
SHIELD WILL STAY SOUTH OF THE AREA. THE GFS WOULD GIVE THE
POSSIBILITY OF A FEW FLURRIES BUT THE EURO KEEPS ALL PRECIPITATION
SOUTH. REINFORCING COLD COMES IN BEHIND THIS SYSTEM FOR FRIDAY AND
SATURDAY AS HIGH PRESSURE BUILD OVER THE REGION.
FOR SUNDAY...AS THE HIGH MOVES EAST OF THE AREA CLOUDS WILL INCREASE
AND TEMPERATURES WILL MODERATE SOME. A WEAK OVERRUNNING SETUP FORMS
SUNDAY NIGHT THAT COULD PRODUCE A PERIOD OF SNOW. ANOTHER WEAK AREA
OF HIGH PRESSURE BRIEFLY BUILDS IN FOR MONDAY.
MODELS AGREE ON BRINGING ANOTHER AREA OF LOW PRESSURE OVER THE
AREA LATE MONDAY NIGHT AND TUESDAY. WITH MODERATING
TEMPERATURES...PRECIPITATION TYPE COULD BECOME A CHALLENGE BY LATE
TUESDAY OVER SOUTHERN AREAS.
&&
.AVIATION /05Z WEDNESDAY THROUGH SUNDAY/...
SHORT TERM...CONDITIONS DETERIORATE TO MVFR LATE THIS EVENING AND
EVENTUALLY IFR IN -SN AT ALL BUT KLEB/KHIE WHERE IT WILL LKLY STAY
MAINLY MVFR IN -SHSN. CONDS WILL IMPROVE QUICKLY TO VFR DURING WED
MORNING BEHIND THIS SYSTEM...WHICH WILL PERSIST INTO WED NIGHT.
LONG TERM...AN AREA OF MVFR CLOUDS WILL BE POSSIBLE THURSDAY AS
LOW PRESSURE MOVES SOUTH OF THE REGION. HIGH PRESSURE WILL RESULT
IN MOSTLY VFR CONDITIONS FRIDAY AND SATURDAY. A WARM FRONT COULD
RESULT IN MVFR CONDITIONS ON SUNDAY AND SUNDAY NIGHT. A PERIOD OF
SNOW IS POSSIBLE SUNDAY NIGHT.
&&
.MARINE...
SHORT TERM...WILL SEE AN INCREASE IN SW FLOW...WHICH COULD PRODUCE
A FEW GUSTS TO NEAR 25 KT LATE TONIGHT...BUT WILL HOLD OFF THE SCA
FOR NOW. BETTER CHC FOR SCA WILL BE IN THE W FLOW BEHIND THE
SYSTEM FROM LATE WED MORNING INTO WED EVE.
LONG TERM...
LOW PRESSURE WILL PASS SOUTH OF THE WATERS THURSDAY. HIGH PRESSURE
WILL BUILD OVER THE WATERS FRIDAY AND SATURDAY FOLLOWED BY THE
APPROACH OF A WARM FRONT SUNDAY. WINDS AND WAVES ARE EXPECTED TO
REMAIN BELOW SCA LEVELS.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR MEZ022-
026>028.
NH...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 10 AM THIS MORNING TO 11 PM EST THIS
EVENING FOR ANZ151-153.
SMALL CRAFT ADVISORY UNTIL 11 PM EST THIS EVENING FOR ANZ150-
152-154.
&&
$$
ES
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1220 PM EST WED FEB 25 2015
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 330 AM EST WED FEB 25 2015
AN ARCTIC AIRMASS WILL REMAIN FIRMLY ENTRENCHED IN THE GREAT LAKES
REGION THROUGH FRIDAY. A WEAK SYSTEM WILL BRING A FEW LIGHT SNOW
SHOWERS TO FAR SOUTHERN LOWER MICHIGAN TONIGHT INTO THURSDAY
MORNING. HIGH PRESSURE WILL BUILD IN TO PRODUCE FAIR BUT COLD
WEATHER THURSDAY THROUGH SATURDAY. TEMPERATURES WILL FINALLY
UNDERGO A GRADUAL MODERATING TREND LATE THIS WEEKEND INTO EARLY
NEXT WEEK.
&&
.UPDATE...
ISSUED AT 1110 AM EST WED FEB 25 2015
THIS IS JUST A QUICK HEADS UP ON MY THINKING FOR TONIGHT. I AM
THINKING IT WILL SNOW TONIGHT (HIGH POP) NEAR AND SOUTH OF I-96.
THIS WILL NOT BE A HEAVY SNOW... MOSTLY AN INCH OR LESS BUT IT
WILL SNOW NONE THE LESS.
AFTER LOOKING AT THE NAM12...RAP13 AND HRRR IT SEEMS TO ME WHAT
WE WILL SEE IS A NARROW BAND OF SNOW DEVELOPING NEAR OR JUST NORTH
OF I-96 AROUND 9 TO 10 PM TONIGHT THAT WILL MOVE SLOWLY SOUTHWARD
(THIS IS SHOWN BY ALL THREE OF THESE MODELS) TO I-94 BY 5 AM. THIS
NARROW BAND IS THE RESULT OF SURFACE FGEN DUE THE RADIATIONAL COOLED
AIR OVER NORTHERN LOWER MICHIGAN COMPARED TO THE CLOUD COVERED AIR
(WHICH WILL NOT COOL) CREATING A THERMAL GRADIENT. THE BEST LIFT
IS JUST ABOVE THE IS NEAR 900 MB WHICH IS IN THE DGZ SO THIS WILL
MAXIMIZE THE SNOWFALL RATES. THIS IS GOING ON UNDER THE ENTRANCE
REGION OF THE UPPER JET SO WE GET DEEP MOISTURE AND DEEP LIFT
(WEAK BUT ALSO IN THE DGZ). AROUND MIDNIGHT THE DGZ OVER GRR IS
FROM 1000 FT TO 12000 FT....MORE THAN DEEP ENOUGH TO HELP THE SNOW
CAUSE. BOTTOM LINE IS I WILL INCREASE THE POP TO OVER 70% OVER THE
SOUTHERN 1/2 OF THE CWA THIS EVENING FOR THIS EVENT.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 330 AM EST WED FEB 25 2015
FAIRLY TRANQUIL AND COLD WEATHER IS ANTICIPATED THROUGH THE SHORT
TERM FCST PERIOD. A FEW LIGHT SNOW SHOWERS AND FLURRIES WILL
LINGER INTO THIS MORNING BUT WITH VERY LITTLE TO NO ADDITIONAL
SNOW ACCUMULATION. MOST OF THE DAY WILL BE DRY BUT COLD WITH A MIX
OF SUN AND CLOUDS. MAX TEMPS WILL ONLY REACH 10 TO 15 DEGREES.
A WEAK SYSTEM MOVING ESE FROM THE NORTHERN PLAINS STATES EARLY
THIS MORNING WILL BRING A FEW LIGHT SNOW SHOWERS AND FLURRIES TO
OUR SOUTHERN FCST AREA NEAR TO MAINLY SOUTH OF I-96 TONIGHT INTO
THURSDAY MORNING... WITH VERY LIGHT SNOW ACCUMULATIONS OF UNDER AN
INCH.
BEYOND THAT HIGH PRESSURE WILL BUILD IN TO PRODUCE FAIR BUT COLD
WX THURSDAY AFTERNOON THROUGH FRIDAY. MAX TEMPS THURSDAY WILL
STRUGGLE TO REACH THE UPPER SINGLE DIGITS TO LOWER TEENS AND MINS
THURSDAY NIGHT WILL FALL TO BELOW ZERO ACROSS OUR AREA AS SKIES
CLEAR AND WITH LIGHT WINDS AND EXPANSIVE SNOW COVER IN PLACE. MAX
TEMPS FRIDAY WILL STRUGGLE TO REACH THE LOWER TO MIDDLE TEENS IN
SPITE OF LOTS OF SUN AFTER A VERY COLD START TO THE DAY.
.LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY)
ISSUED AT 330 AM EST WED FEB 25 2015
UPPER AIR PATTERN SHIFT IS STILL FORECAST TO OCCUR BY THE 00Z MODEL
RUNS DURING THE LONG TERM. THE PERSISTENT UPPER TROUGH IS IN THE
PROCESS OF LIFTING OUT FRIDAY NIGHT. BY EARLY NEXT WEEK A SOUTHWEST
FLOW DEVELOPS ACROSS THE LOWER 48...FROM THE SOUTHWEST U.S. TO THE
GREAT LAKES.
THERE ARE TWO MAIN ITEMS TO KEEP AN EYE ON THROUGH THE PERIOD. THE
FIRST IS THE SNOW EVENT FOR SUNDAY AND SUNDAY NIGHT. IT REMAINS AN
EVENT WITH NO SURFACE LOW TO KEY ON. SNOW IS PRODUCED VIA A WEAK
FRONTAL BOUNDARY SLIPPING THROUGH THE AREA COUPLED WITH AN UPPER
LEVEL SHORT WAVE AND ISENTROPIC LIFT. IT APPEARS TO BE A 2-5 INCH
SNOW POTENTIALLY FOR THE SOUTHERN HALF OF THE FORECAST AREA. WE
STILL HAVE PLENTY OF TIME TO NAIL DOWN THE DETAILS WITH THIS SYSTEM.
THE SECOND SIGNIFICANT FEATURE TO KEEP AN EYE ON IS A SYSTEM NEXT
WEEK IN THE TUESDAY OR WEDNESDAY TIME FRAME. LOW CONFIDENCE IN THIS
TIME FRAME AS THE GFS IS QUICKER...BRINGING A DEEP LOW THROUGH THE
AREA ON TUESDAY. THE ECMWF AND CANADIAN ARE SLOWER AND BRING THE
SYSTEM THROUGH ON WEDNESDAY. AT THIS POINT...SIDING WITH THE ECMWF
AND CANADIAN AND THE SLOWER SYSTEM. THE SYSTEM TAPS GULF MOISTURE IN
DEEP SOUTHERLY FLOW. PRECIPITATION TYPE ISSUES COME INTO PLAY
TUESDAY NIGHT IN THE ECMWF/CANADIAN SOLUTIONS WITH +4 TO +6 850MB
AIR SURGING IN FROM THE SOUTH. THESE VALUES WOULD YIELD RAIN AS THE
PRECIP TYPE ALONG I94. MODELS ARE HAVING ISSUES WITH THIS SYSTEM AS
ITS DRIVEN BY A WAVE EJECTING OUT OF THE SOUTHWEST U.S. TROUGH. WE
WILL BE MONITORING TRENDS WITH THIS SYSTEM IN THE COMING DAYS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1219 PM EST WED FEB 25 2015
OUR MAIN CONCERN WITH THE 18Z FCSTS IS DEALING WITH THE SNOW
COMING IN FROM LATE THIS AFTERNOON THROUGH THU MORNING. MID CLOUDS
ARE NOW STARTING TO STREAM IN OVER THE AREA...WITH SOME
DIURNAL/LAKE EFFECT CLOUD COVER NOW STARTING TO DEVELOP/MOVE
INLAND. WE EXPECT THAT ONLY KMKG WILL SEE THE LOWEST CONDITIONS
THIS AFTERNOON WITH 3500 FT CIGS AND SOME FLURRIES.
LIGHT SNOW WILL THEN BREAK OUT ACROSS THE TERMINALS THIS EVENING
INTO THE EARLY OVERNIGHT HOURS. MODELS ARE INDICATING THAT A LOCAL
BAND MAY SET UP AND POTENTIALLY IMPACT THE KGRR AREA FOR A SHORT
TIME THIS EVENING WITH SOME LOWER VSBYS. MVFR IS LIKELY WITH SOME
LOCAL IFR POSSIBLE.
A LIGHT SNOW WILL THEN LIKELY PERSIST OVERNIGHT AND INTO THU
MORNING. THIS WILL LAST LONGER ACROSS THE SOUTH. THE LOWER
CONDITIONS WILL ALSO BE ACROSS THE SOUTH CLOSER TO THE SYSTEM.
AGAIN...MVFR IS LIKELY WITH SOME IFR POSSIBLE AT TIMES. THIS WILL
GRADUALLY MOVE OUT THU MORNING. CONDITIONS WILL IMPROVE GRADUALLY
THU AFTERNOON.
&&
.HYDROLOGY...
ISSUED AT 224 PM EST TUE FEB 24 2015
CURRENTLY NO SUSPECTED ICE JAMS AND RIVER LEVELS ARE HOLDING RATHER
STEADY. FORECAST CALLS FOR BELOW FREEZING TEMPERATURES INTO NEXT
WEEK WITH OCCASIONAL SNOW OPPORTUNITIES. THE RISK OF FLOODING IS
FAIRLY LIMITED UNTIL A NOTABLE WARM-UP OR RAIN EVENT.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
UPDATE...WDM
SYNOPSIS...LAURENS
SHORT TERM...LAURENS
LONG TERM...DUKE
AVIATION...NJJ
HYDROLOGY...CAS
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1110 AM EST WED FEB 25 2015
LATEST UPDATE...
UPDATE
.SYNOPSIS...
ISSUED AT 330 AM EST WED FEB 25 2015
AN ARCTIC AIRMASS WILL REMAIN FIRMLY ENTRENCHED IN THE GREAT LAKES
REGION THROUGH FRIDAY. A WEAK SYSTEM WILL BRING A FEW LIGHT SNOW
SHOWERS TO FAR SOUTHERN LOWER MICHIGAN TONIGHT INTO THURSDAY
MORNING. HIGH PRESSURE WILL BUILD IN TO PRODUCE FAIR BUT COLD
WEATHER THURSDAY THROUGH SATURDAY. TEMPERATURES WILL FINALLY
UNDERGO A GRADUAL MODERATING TREND LATE THIS WEEKEND INTO EARLY
NEXT WEEK.
&&
.UPDATE...
ISSUED AT 1110 AM EST WED FEB 25 2015
THIS IS JUST A QUICK HEADS UP ON MY THINKING FOR TONIGHT. I AM
THINKING IT WILL SNOW TONIGHT (HIGH POP) NEAR AND SOUTH OF I-96.
THIS WILL NOT BE A HEAVY SNOW... MOSTLY AN INCH OR LESS BUT IT
WILL SNOW NONE THE LESS.
AFTER LOOKING AT THE NAM12...RAP13 AND HRRR IT SEEMS TO ME WHAT
WE WILL SEE IS A NARROW BAND OF SNOW DEVELOPING NEAR OR JUST NORTH
OF I-96 AROUND 9 TO 10 PM TONIGHT THAT WILL MOVE SLOWLY SOUTHWARD
(THIS IS SHOWN BY ALL THREE OF THESE MODELS) TO I-94 BY 5 AM. THIS
NARROW BAND IS THE RESULT OF SURFACE FGEN DUE THE RADIATIONAL COOLED
AIR OVER NORTHERN LOWER MICHIGAN COMPARED TO THE CLOUD COVERED AIR
(WHICH WILL NOT COOL) CREATING A THERMAL GRADIENT. THE BEST LIFT
IS JUST ABOVE THE IS NEAR 900 MB WHICH IS IN THE DGZ SO THIS WILL
MAXIMIZE THE SNOWFALL RATES. THIS IS GOING ON UNDER THE ENTRANCE
REGION OF THE UPPER JET SO WE GET DEEP MOISTURE AND DEEP LIFT
(WEAK BUT ALSO IN THE DGZ). AROUND MIDNIGHT THE DGZ OVER GRR IS
FROM 1000 FT TO 12000 FT....MORE THAN DEEP ENOUGH TO HELP THE SNOW
CAUSE. BOTTOM LINE IS I WILL INCREASE THE POP TO OVER 70% OVER THE
SOUTHERN 1/2 OF THE CWA THIS EVENING FOR THIS EVENT.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 330 AM EST WED FEB 25 2015
FAIRLY TRANQUIL AND COLD WEATHER IS ANTICIPATED THROUGH THE SHORT
TERM FCST PERIOD. A FEW LIGHT SNOW SHOWERS AND FLURRIES WILL
LINGER INTO THIS MORNING BUT WITH VERY LITTLE TO NO ADDITIONAL
SNOW ACCUMULATION. MOST OF THE DAY WILL BE DRY BUT COLD WITH A MIX
OF SUN AND CLOUDS. MAX TEMPS WILL ONLY REACH 10 TO 15 DEGREES.
A WEAK SYSTEM MOVING ESE FROM THE NORTHERN PLAINS STATES EARLY
THIS MORNING WILL BRING A FEW LIGHT SNOW SHOWERS AND FLURRIES TO
OUR SOUTHERN FCST AREA NEAR TO MAINLY SOUTH OF I-96 TONIGHT INTO
THURSDAY MORNING... WITH VERY LIGHT SNOW ACCUMULATIONS OF UNDER AN
INCH.
BEYOND THAT HIGH PRESSURE WILL BUILD IN TO PRODUCE FAIR BUT COLD
WX THURSDAY AFTERNOON THROUGH FRIDAY. MAX TEMPS THURSDAY WILL
STRUGGLE TO REACH THE UPPER SINGLE DIGITS TO LOWER TEENS AND MINS
THURSDAY NIGHT WILL FALL TO BELOW ZERO ACROSS OUR AREA AS SKIES
CLEAR AND WITH LIGHT WINDS AND EXPANSIVE SNOW COVER IN PLACE. MAX
TEMPS FRIDAY WILL STRUGGLE TO REACH THE LOWER TO MIDDLE TEENS IN
SPITE OF LOTS OF SUN AFTER A VERY COLD START TO THE DAY.
.LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY)
ISSUED AT 330 AM EST WED FEB 25 2015
UPPER AIR PATTERN SHIFT IS STILL FORECAST TO OCCUR BY THE 00Z MODEL
RUNS DURING THE LONG TERM. THE PERSISTENT UPPER TROUGH IS IN THE
PROCESS OF LIFTING OUT FRIDAY NIGHT. BY EARLY NEXT WEEK A SOUTHWEST
FLOW DEVELOPS ACROSS THE LOWER 48...FROM THE SOUTHWEST U.S. TO THE
GREAT LAKES.
THERE ARE TWO MAIN ITEMS TO KEEP AN EYE ON THROUGH THE PERIOD. THE
FIRST IS THE SNOW EVENT FOR SUNDAY AND SUNDAY NIGHT. IT REMAINS AN
EVENT WITH NO SURFACE LOW TO KEY ON. SNOW IS PRODUCED VIA A WEAK
FRONTAL BOUNDARY SLIPPING THROUGH THE AREA COUPLED WITH AN UPPER
LEVEL SHORT WAVE AND ISENTROPIC LIFT. IT APPEARS TO BE A 2-5 INCH
SNOW POTENTIALLY FOR THE SOUTHERN HALF OF THE FORECAST AREA. WE
STILL HAVE PLENTY OF TIME TO NAIL DOWN THE DETAILS WITH THIS SYSTEM.
THE SECOND SIGNIFICANT FEATURE TO KEEP AN EYE ON IS A SYSTEM NEXT
WEEK IN THE TUESDAY OR WEDNESDAY TIME FRAME. LOW CONFIDENCE IN THIS
TIME FRAME AS THE GFS IS QUICKER...BRINGING A DEEP LOW THROUGH THE
AREA ON TUESDAY. THE ECMWF AND CANADIAN ARE SLOWER AND BRING THE
SYSTEM THROUGH ON WEDNESDAY. AT THIS POINT...SIDING WITH THE ECWMF
AND CANADIAN AND THE SLOWER SYSTEM. THE SYSTEM TAPS GULF MOISTURE IN
DEEP SOUTHERLY FLOW. PRECIPITATION TYPE ISSUES COME INTO PLAY
TUESDAY NIGHT IN THE ECMWF/CANADIAN SOLUTIONS WITH +4 TO +6 850MB
AIR SURGING IN FROM THE SOUTH. THESE VALUES WOULD YIELD RAIN AS THE
PRECIP TYPE ALONG I94. MODELS ARE HAVING ISSUES WITH THIS SYSTEM AS
ITS DRIVEN BY A WAVE EJECTING OUT OF THE SOUTHWEST U.S. TROUGH. WE
WILL BE MONITORING TRENDS WITH THIS SYSTEM IN THE COMING DAYS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 710 AM EST WED FEB 25 2015
SCATTERED TO BROKEN CLOUDS ARE IN PLACE ACROSS SOUTHWEST LOWER
MICHIGAN AT 12Z. THE BULK OF THE CLOUDS WERE LOCATED TOWARDS LAKE
MICHIGAN IN A NORTHWEST FLOW. EXPECTING SCATTERED TO BROKEN CLOUDS
TO CONTINUE THROUGH THE DAY...WITH CEILINGS VARYING BETWEEN VFR
AND MVFR.
TONIGHT...SOME LIGHT SNOW WILL SPREAD IN FROM THE WEST...WITH MVFR
CEILINGS BECOMING MORE PREVALENT...ESPECIALLY TOWARDS THE I-94 TAF
SITES FROM KAZO TO KJXN.
WINDS THROUGH THE PERIOD WILL BE FAIRLY LIGHT SHIFTING FROM THE
NORTHWEST TO THE NORTHEAST THE NEXT 24 HOURS.
&&
.HYDROLOGY...
ISSUED AT 224 PM EST TUE FEB 24 2015
CURRENTLY NO SUSPECTED ICE JAMS AND RIVER LEVELS ARE HOLDING RATHER
STEADY. FORECAST CALLS FOR BELOW FREEZING TEMPERATURES INTO NEXT
WEEK WITH OCCASIONAL SNOW OPPORTUNITIES. THE RISK OF FLOODING IS
FAIRLY LIMITED UNTIL A NOTABLE WARM-UP OR RAIN EVENT.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
UPDATE...WDM
SYNOPSIS...LAURENS
SHORT TERM...LAURENS
LONG TERM...DUKE
AVIATION...DUKE
HYDROLOGY...CAS
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
546 AM CST WED FEB 25 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 408 AM CST WED FEB 25 2015
FIRST OFF...WE WILL START WITH WHAT GOT CHANGED OVERNIGHT. SNOW
ACROSS NODAK HAS COME IN CONSIDERABLY FARTHER NE THAN WHAT PREVIOUS
MODELS EVEN YESTERDAY AFTERNOON WERE SHOWING. THE HRRR/RAP/HOPWRF
ALL PICKED UP ON THIS NORTHWARD SHIFT IN THE SNOW AND THE FORECAST
WAS UPDATED ACCORDINGLY. NOW HAVE AN INCH OF SNOW FORECAST AS FAR
NORTH AS A MORRIS...MSP...PEPIN LINE. HAVE ALSO BOOSTED SNOW TOTALS
TO THE SOUTH OF THERE...WITH THREE 3+ INCHES FORECAST AS FAR NORTH
AS THE MN RIVER TO ALBERT LEA. WITH THE HIGHER SNOW AMOUNTS...DID
EXPAND THE ADVY UP TO THE UPPER MN RIVER AND ALONG THE I-90
CORRIDOR. WE WILL HAVE TO KEEP A CLOSE EYE SOUTHWEST OF A ST. JAMES
TO ALBERT LEA LINE AS SNOW TOTALS THERE ARE CURRENTLY IN THE 4-6
INCH RANGE AND THERE IS THE POTENTIAL A FEW OF THOSE COUNTIES MAY
NEED TO BE UPGRADED TO A WARNING IF QPF COMES IN ANY HIGHER THAN
WHAT IT IS CURRENTLY PEGGED TO BE.
RAP H5 ANALYSIS THIS MORNING SHOWS TWO WAVES OF INTEREST OUT IN THE
DAKOTAS...ONE IS MOVING INTO CENTRAL SODAK...WHILE THE SECOND IS
MOVING INTO NW NODAK. THE SNOW CURRENTLY MOVING INTO SW MN IS THE
RESULT OF THE SRN WAVE...BUT THIS NRN WAVE WILL BE THE DOMINATE
PLAYER TODAY...WHICH LIKELY EXPLAINS THE NORTHWARD SHIFT WE HAVE
SEEN IN THE GUIDANCE OVERNIGHT. BESIDE THESE WAVES...THERE IS A
PRETTY STRONG NW-SE ORIENTED H85 THERMAL GRADIENT THAT LINES UP FROM
NW NODAK INTO NW IOWA AND WITHIN THIS BAROCLINIC ZONE YOU WILL FIND
OUR DEVELOPING SNOWSTORM. AS WE GO THROUGH THE DAY...THIS NW-SE
GRADIENT WILL TAKE ON MORE OF E-W GRADIENT...WITH THE PIVOT IN THE
GRADIENT HAPPENING ACROSS NORTHERN IOWA...WHICH IS WHY THE 3Z AND 6Z
HOPWRF GO ABSOLUTELY GANGBUSTERS WITH PUTTING OUT OVER A FOOT OF
SNOW IN NORTH CENTRAL IOWA.
FOR THIS FORECAST...THE HOPWRF/RAP/HRRR ARE NEARLY IDENTICAL WITH
HOW FAR NORTH THE 0.25" QPF LINE WILL SETUP...SO FELT CONFIDENT IN
EXPANDING THE WINTER WEATHER ADVISORY ACROSS THE I-90 CORRIDOR AND
UP THE MN RIVER TO YELLOW MEDICINE AND LAC QUI PARLE COUNTIES. GIVEN
HOW COLD THE ATMO IS...WE ARE LOOKING AT SNOW RATIOS LIKELY UP NEAR
20:1...SO A QUARTER INCH OF QPF SHOULD HAVE NO PROBLEM PUTTING DOWN
MORE THAN 3 INCHES OF SNOW. AS MENTIONED ABOVE...THE QPF/SNOWFALL
FORECASTS FROM THE HOPWRF/HRRR/RAP DOWN AROUND FAIRMONT ARE A BIT
WORRISOME AND THERE IS CERTAINLY A GOOD CHANCE WE MAY NEED A WARNING
OR TWO IN SOUTH CENTRAL MN.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 408 AM CST WED FEB 25 2015
A TRANQUIL PERIOD IS EXPECTED THROUGH THE MAJORITY OF THE LONG
TERM. THINGS GET A LITTLE MORE INTERESTING EARLY NEXT WEEK BUT
WE/LL SEE HOW LONG THAT LASTS GIVEN THIS WINTER.
ANOTHER MASSIVE AREA OF HIGH PRESSURE SLIDING DOWN THE EASTERN
SLOPES OF THE ROCKIES WILL BRING A FRESH SURGE OF ARCTIC AIR
THURSDAY AND FRIDAY. MIXING TO 925 MB THURSDAY ONLY YIELDS HIGHS
IN THE LOW SINGLE DIGITS. FULL SUN IS EXPECTED AND WHILE STILL
WEAK...THE HIGHER ANGLE MAY BR ABLE TO SQUEEZE OUT AN EXTRA DEGREE
OR TWO. THE CENTER OF THE RIDGE WILL SINK SOUTHEAST ACROSS THE
EASTERN DAKOTAS OVER THE MISSOURI RIVER THURSDAY NIGHT. WINDS WILL
LIKELY DECOUPLE IN SHELTERED AREAS AND VERY COLD LOWS APPEAR
PROBABLE...PARTICULARLY CLOSEST TO THE HIGH IN SOUTHWEST
MN...WHICH ALSO COINCIDES WITH THE DEEP SNOWPACK NOW EXPECTED FROM
THE SYSTEM TODAY. LOWERED TEMPS SEVERAL DEGREES IN THIS AREA AND
THE COLDEST LOCATIONS COULD APPROACH 20 BELOW. ALTHOUGH TOO
COLD...THE 00Z GEM IS THE BEST PROXY TO PLACE WHERE THE COLDEST
TEMPS SHOULD OCCUR.
MODERATING TEMPS WILL RETURN FOR THE WEEKEND AS A SOUTHERLY
SURFACE FLOW AND A WEAKENING OF THE CENTRAL AND EASTERN CONUS
TROUGH NEGATE THE OCCURRENCE OF ADDITIONAL ARCTIC AIR INTRUSION.
OF PARTICULAR INTEREST IS A LOADING OF ENERGY ACROSS THE
SOUTHWESTERN U.S. IN A DEEPENING POSITIVELY TILTED TROUGH
EXTENDING OFF THE SOCAL COAST. A ZONAL UPPER JET EXTENDING TO THE
EAST WILL WICK AWAY PIECES OF THIS ENERGY AND EJECT THEM ACROSS
THE CENTRAL PLAINS EAST TO THE OHIO VALLEY. ANY INFLUENCES WITH
THESE WAVES SHOULD REMAIN SOUTH OF THE FORECAST AREA. LOWERED POPS
THIS WEEKEND BUT DID NOT COMPLETELY REMOVE THEM YET ACROSS SRN MN
AND WRN WI.
BY LATE IN THE WEEKEND...THERE ARE STRONG INDICATIONS THE JET
STREAM WILL FINALLY BUCKLE NORTH AS MID LEVEL RIDGING BUILDS
ACROSS THE SOUTHEAST. THIS WILL BEGIN TO SET THE STAGE FOR A
SIGNIFICANT PATTERN SHIFT NEXT WEEK BUT THE DETAILS ARE FAR FROM
CERTAIN WITH A COMPLEX EVOLUTION OF THE SOUTHWESTERN TROUGH THAT
COULD LEAD TO BIG DIFFERENCES DOWNSTREAM. AT THE MOMENT...THE
DETERMINISTIC RUNS OF THE GFS...ECMWF...AND CANADIAN ALL AGREE IN
A FAIRLY ROBUST WINTER STORM IMPACTING PORTIONS OF THE PLAINS AND
UPPER MIDWEST EARLY NEXT WEEK. HOWEVER...ENSEMBLE MEMBERS ARE ALL
OVER THE PLACE. WE HAVE SEEN SYSTEMS TREND AWAY FROM THE LOCAL
AREA TIME AND TIME AGAIN THIS WINTER...BUT THE SOUTHEAST RIDGE
BOLSTERS OUR PROBABILITIES A BIT MORE AND THUS THIS PERIOD WILL
NEED TO BE WATCHED.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 546 AM CST WED FEB 25 2015
SNOW RAPIDLY EXPANDING ACROSS SW MN THIS MORNING HAS BEEN HANDLED
WELL BY THE HRRR AND HOPWRF...AND STUCK CLOSE TO THOSE MODELS
FOR TIMING SNOW ACROSS SRN MN THIS MORNING. ONLY SURPRISE SO FAR
HAS BEEN THE SNOW BEING REPORTED AT AXN...DID NOT EXPECT THE SNOW
TO MAKE IT THAT FAR NE...BUT THAT DOES BODE WELL FOR MSP SEEING AT
LEAST A FEW TENTHS OF AN INCH OF SNOW THIS MORNING. STC/RNH/EAU
STILL LOOK TO MISS THIS ONE. FOR RWF...NOTHING HAS CHANGED...THEY
WILL STILL FEEL THE BRUNT OF THIS SYSTEM...WITH CLOSE TO 3 INCHES
EXPECTED. NON VFR CONDITIONS LOOKS TO BE BASICALLY TIED TO THE
SNOWFALL...SO EXPECT VFR CONDITIONS TO MOVE IN QUICKLY BEHIND THE
SNOW THIS AFTERNOON...WITH SUBSIDENCE AND COLD/DRY AIR FROM THE
NEXT INCOMING HIGH LEADING TO SKIES CLEARING OUT OVERNIGHT AND
MAINLY CLEAR CONDS FOR THU/FRI.
KMSP...MSP WILL BE ON THE EDGE OF THE SNOW SHIELD. LAST COUPLE
RUNS OF THE HRRR HAVE SHOWN THE 1 INCH SNOW LINE GETTING TO ABOUT
5 MILES SOUTH OF THE AIRPORT...WHILE NOTHING FALLS 5 MILES NORTH
OF THE FIELD...SO NEEDLESS TO SAY...MSP COULD GO EITHER WAY WITH
GETTING OR NOT GETTING SNOW THIS MORNING. HOWEVER...THE FACT THAT
-SN IS CURRENTLY BEING OBSERVED AS FAR NE AS AXN AND SAUK CENTER
/AS WELL AS HERE AT THE OFFICE IN CHANHASSEN/...STILL FEEL MSP
WILL SEE SOME LIGHT SNOW...ESPECIALLY BETWEEN 15Z AND 18Z. AS FOR
THE REST OF THE TAF...CONFIDENCE IS HIGH IN VFR CONDS WITH NORTH
WINDS AROUND 10KTS.
/OUTLOOK FOR KMSP/
THU...VFR. WINDS NW 5-10 KTS.
FRI...VFR. WINDS WSW 5 KTS.
SAT...VFR. WINDS S 10G15 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER WEATHER ADVISORY UNTIL 1 PM CST THIS AFTERNOON FOR MNZ054-
064-073-074.
WINTER WEATHER ADVISORY UNTIL 3 PM CST THIS AFTERNOON FOR MNZ082-
083-091>093.
WI...NONE.
&&
$$
SHORT TERM...MPG
LONG TERM...BORGHOFF
AVIATION...MPG
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON MS
1135 AM CST WED FEB 25 2015
.DISCUSSION...MESSY AND COMPLEX WEATHER SITUATION ACROSS THE REGION
THIS MORNING WITH A WIDE RANGE OF PRECIP TYPES ACROSS THE CWA. OVER
THE NORTH AND WEST OF THE AREA...TEMPERATURES HAVE BEEN HOVERING
NEAR FREEZING THROUGHOUT THE MORNING...WITH PREDOMINATELY SLEET AND
LIGHT FREEZING RAIN. AS FAR SOUTH AS HINDS...MADISON...NEWTON AND
LAUDERDALE COUNTIES...WE HAVE BEEN RECEIVING REPORTS OF NEW ICE
ACCUMULATIONS ON TREES AND POWERLINES AND EVEN NEW POWER OUTAGES
RESULTING FROM LARGE LIMBS BREAKING. GENERALLY SOUTH OF I-20 (EXCEPT
FOR IN NE LOUISIANA)...PRECIP IS ALL LIQUID. IN THE DELTA...WE ARE
NOW BEGINNING TO SEE A TRANSITION TO SLEET THEN SNOW. THE SWITCH TO
SNOW HAS JUST TAKEN PLACE IN OUR SOUTHEAST AR COUNTIES AND WILL BE
OCCURRING ACROSS THE RIVER INTO THE CLEVELAND AND GREENVILLE AREAS
SHORTLY. JUST WEST OF THE CWA...THE TRANSITION TO MODERATE AND AT
TIMES HEAVY SNOW HAS BEEN FAST...AND SNOWFALL RATES HAVE BEEN HIGH
AT TIMES WITH ACCUMULATIONS OF 2-3 INCHES TAKING PLACE OVER PARTS OF
SOUTH AR AND NORTH LA WITHIN JUST THE PAST FEW HOURS.
THROUGH THE MORNING...THE HRRR HAS HANDLED THE SLOWER TRANSITION TO
ALL SNOW WELL AS THE MID LEVEL VORT SWINGS INTO THE AREA MORE IN THE
AFTERNOON. DESPITE THE LATER TRANSITION...IT STILL INDICATES HEAVIER
SNOW ALONG THE HIGHWAY 82 CORRIDOR AS DYNAMIC COOLING OCCURS IN THE
COLD CORE. THIS SCENARIO WAS COVERED PRETTY WELL IN THE PREVIOUS
DISCUSSION...AND OUR FORECAST THINKING HAS CHANGED LITTLE THUS
FAR...EXCEPT TO PUSH BACK THE START OF HEAVIER SNOW A FEW HOURS. WE
ALSO STILL CANNOT RULE OUT THUNDER IN CONVECTIVE BANDS...AND REPORTS
OF THIS HAVE BEEN RECEIVED BACK TO OUR WEST ALREADY THIS MORNING.
FOR THE UPDATE IT WAS NECESSARY TO CHANGE THE PROPORTION OF ICE/SNOW
ACCUMS DURING THE EARLY DAY TIME FRAME BASED ON THE GREATER
PREVALENCE OF FREEZING RAIN. HOWEVER...HEAVIEST SNOW ACCUMS ARE
STILL IN THE LATER PORTION OF THE DAY AND NO MAJOR ADJUSTMENTS WERE
MADE TO THESE. STILL EXPECTING THE HIGHEST ACCUMULATIONS ALONG AND
NORTH OF THE HIGHWAY 82 CORRIDOR. OTHER ELEMENTS OF THE FORECAST
WERE GENERALLY ON TRACK AND NO MAJOR ADJUSTMENTS WILL BE MADE AT
THIS TIME. /DL/
&&
.AVIATION...PLENTY OF AVIATION ISSUES TODAY. VSBY RESTRICTED BY RAIN
AND SOON TO BE BY SNOW. HAVE CARRIED VSBY REDUCTIONS TO 1/2SM AT
KGLH...KGWO AND KGTR THIS AFTERNOON FOR SEVERAL HOURS. WILL WATCH
FOR FURTHER RESTRICTIONS SPECIFICALLY AT KJAN AND KHKS THIS
AFTERNOON.
CEILINGS ARE IFR AT SEVERAL SITES AND A FURTHER LOWERING IS EXPECTED
THIS AFTERNOON...AND WILL CONTINUE IN THE IFR CATEGORY AFTER THE
STORM PASSES THIS EVENING AND OVERNIGHT. FORTUNATELY...THIS STORM
HAS NO WINDS TO SPEAK OF. /SW/
&&
.PREV DISCUSSION... /ISSUED AT 458 AM CST WED FEB 25 2015/
SHORT TERM...THROUGH THURSDAY NIGHT...AS RAPIDLY AS THE SYSTEM CAME
IN IT WILL EXIT BY LATE THIS AFTERNOON/EVENING. THE HEAVIER PRECIP
WILL TAPER OFF TO LIGHT WITH THE I20 CORRIDOR SEEING THE MIX CHANGE
OVER TO LIGHT SNOW/FLURRIES BEFORE ENDING. CLOUD COVER LOOKS TO EXIT
PRETTY CLOSE ON THE HEELS OF THE PRECIP AS WELL. WITH CLEAR
SKIES...CALM WINDS AND INCREASED ALBEDO FROM THE SNOW COVER...EXPECT
TEMPS TO DROP LIKE A ROCK OVERNIGHT WITH LOW TO MID 20S OVER THE
NORTH AND NEAR 30 OVER THE FAR SOUTH./26/
LONG TERM...FRIDAY THROUGH WEDNESDAY...COOL HIGH PRESSURE FROM A
HIGH CENTERED OVER THE OHIO VALLEY WILL PREVAIL ACROSS THE REGION ON
FRIDAY. TEMPERATURES WILL CONTINUE TO BE COLD WITH LOWS IN THE 20S
AND HIGHS ONLY CLIMBING INTO THE 40S TO AROUND 50 IN THE SOUTH.
AS THE SURFACE HIGH SHIFTS TO THE EAST COAST ON SATURDAY THE SURFACE
FLOW WILL BECOME MORE EASTERLY AND EVENTUALLY SOUTHEASTERLY BY
SUNDAY. TEMPERATURES WILL BE ON THE RISE ON SATURDAY WITH WARMER
HIGHS IN THE UPPER 40S TO UPPER 50S IN THE SOUTH. AS THE FLOW
BECOMES SOUTHERLY SATURDAY NIGHT INTO SUNDAY MOISTURE WILL INCREASE
ACROSS THE AREA. THE GFS/ECMWF ARE IN GOOD AGREEMENT THAT A WARM
FRONT WILL PUSH NORTHWARD ALONG WITH INCREASING INSTABILITY SUNDAY
AFTERNOON AND THIS WILL KICK OF SOME THUNDERSTORM ACTIVITY. THIS IS
SEVERAL DAYS OUT...BUT CURRENTLY IT LOOKS LIKE THERE IS SOME
POTENTIAL FOR ELEVATED STRONG STORMS SUNDAY AFTERNOON WITH HAIL
BEING THE MAIN CONCERN.
ON MONDAY THE GFS AND ECMWF ARE GENERALLY IN DECENT AGREEMENT OF
SOUTHWEST FLOW ALOFT AND WEAK UPPER RIDGING ...BUT DIFFER ON THE
PLACEMENT OF THE FRONTAL BOUNDARY WITH THE GFS FURTHER SOUTH OVER THE
AREA WHILE THE ECMWF IS WELL TO THE NORTH. WILL LEAN TOWARDS THE
ECMWF WHICH WILL ALLOW MUCH WARMER TEMPERATURES OVER THE AREA ON
MONDAY. FROM MONDAY BOTH THE GFS/ECMWF MOVE A SERIES OF SHORT WAVES
ACROSS THE PLANES INTO THE OHIO VALLEY THROUGH THE REMAINDER OF THE
PERIOD. THE MODELS DIFFER ON THE TIMING OF THESE SYSTEMS...BUT BOTH
OF THE MODELS KEEP THE UPPER HEIGHTS FAIRLY HIGH WITH MOST OF THE
ENERGY REMAINING TO THE NORTH. CIPS ANALOGS INDICATE THAT THERE IS AN
INCREASED RISK FOR SEVERE THUNDERSTORMS BY MIDWEEK AND BOTH THE GFS
AND ECMWF HAVE A MORE POTENT SYSTEM DURING THIS PERIOD ALSO. WITH
THIS OVERALL PATTERN EXPECT THERE WILL BE A GOOD CHANCE FOR SEVERE
THUNDERSTORMS NEXT WEEK AS THERE WILL BE PLENTY OF MOISTURE AND
INSTABILITY TO WORK WITH./15/
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...WINTER STORM WARNING UNTIL MIDNIGHT CST TONIGHT FOR MSZ018-019-
025>042.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR
MSZ043>053.
LA...WINTER STORM WARNING UNTIL 6 PM CST THIS EVENING FOR LAZ007>009-
015.
WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR LAZ016-
023>025.
AR...WINTER STORM WARNING UNTIL 6 PM CST THIS EVENING FOR ARZ074-075.
&&
$$
DL/SW/26/15/
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1125 AM CST Wed Feb 25 2015
.UPDATE...
Issued at 1005 AM CST WED FEB 25 2015
This morning`s model runs, including the short-term HRRR and RAP,
continue to trend a bit further east with the surface low track which
now looks to track from near Maryville to just west of Chillicothe to
near Boonville. Didn`t make any significant changes to snow amounts
to the east of the low track, still generally 2" to 4" across the
advisory area, but it now looks like anything more than 4" will be
just outside our CWA across southeast IA. With the surface low
tracking over Maryville, any advisory-level snows should fall just
east of Nodaway County so this county was removed from the winter
weather advisory.
To the west of the low track, any precipitation will be limited to a
short-window just behind a cold front which will track through later
this evening. This front will bring a rapid drop in temperatures so
that any precipitation that starts as rain should quickly be able to
switch to snow. Decent post-frontal convergence and shallow low-
level frontogenesis may still be able to squeeze out a quick sprinkle
or snow shower despite the recent runs of the RAP and HRRR keeping
these areas completely dry. However the odds of any snow accumulation
reaching an inch or more are low. Updated the forecast for the KC
metro and points south and west to keep snow amounts generally under
a half inch. The bigger concern for these areas will be potential
flash-freezing of any rain or melting snow that does fall, with
temperatures forecast to be dropping into the 20s across all areas by
midnight.
&&
.SHORT TERM...(Today through Friday)
Issued at 412 AM CST WED FEB 25 2015
Water vapor showing well anticipated shortwave trough dropping through
the northern Rockies this morning...with associated sfc reflection
now analyzed along the central Nebraska/South Dakota border. Out
ahead of the sfc low...latest sfc obs show a stationary boundary
extending east-southeast through southern Iowa into northern Illinois
and Indiana. With time today...main shortwave and sfc low will
continue tracking along this boundary before passing over the lower
Missouri Valley later tonight. As has been advertised in recent
days...region remains in the cross-hairs for accumulating snowfall
later tonight as system passes overhead. One would think that the
fcst would have been fairly easy this morning with us being so close
to event start time...but that could not be further from the truth as
latest 00z guidance has come in with a more northward track of the
main sfc low later tonight. With this being the case...our region stands
an excellent chance of warming quite a bit higher than previously
thought...which adds a fair amount of complexity to the going
forecast. Out ahead of the low...southwest downslope winds will
combine with modest warm air advection to allow temperatures to reach
the lower to middle 50s across west-central Missouri and eastern
Kansas to include the KC and STJ metros. To the east...a lingering
snowpack remains in place along and north of the Missouri River which
will likely result in a fairly impressive thermal gradient later this
afternoon. Meanwhile areas north of Route 36 also stand a decent
chance of warming up today as much of far northern Missouri also remains
snow free. In any event...warmer temps and the overall delay of the
system/s arrival by a few hours has resulted in changes to the fcst
to include snow total amounts.
As a result of the delayed arrival...latest models show precip
struggling to work into the area by 21z. With warmer temps in
place...precip will likely start out as rain across much of the
area...before cold air finally begins working into the region later
in the evening behind the main cold front. With limited winter precip
expected this afternoon...have elected to delay the winter weather
advisory start time until 21z this afternoon...and that may still be
a bit to early. In any event...models show main QPF max sliding
southeast over the area mainly between 00 and 06z tonight...with
precip gradually coming to an end from west to east during the early
morning hrs. Considering the amount of warming during the day...warm
ground temps should limit overall accumulations early on...before
precip rates increase heading into the early overnight hrs. In terms
of accumulations...expect maybe an inch in the greater KC area...with
even less across our eastern Kansas and our west-central Missouri
zones south of I-70. Further east where the heavier precip is
expected...have trimmed back on snowfall amounts slightly as fast
storm movement and delayed precip arrival time will likely lead to
slightly lower amounts. In general across the advisory area...expect
2-4" across most locations...however 3-5" will be possible north of
Kirksville before all is said and done. Cannot rule out a 6" report
up there but did not have enough confidence to even consider a
possible warning upgrade. As alluded to above...best accumulations
likely to occur after 00z...hence supporting the decision to slide
the advisory start time to the right.
Another factor to consider overnight will be the strong winds
with cold air advection following fropa. Current BUFKIT momentum
transfer tool output suggesting gusts in the mid to upper 30 kt range
later tonight. Combine this with any falling snow....blowing and
drifting will certainly be a possibility overnight.
Lingering light snow shwrs to come to an end by mid morning Thursday
as drier air and strong high pressure builds into the area. For the
remainder of the short term...focus will be on well below normal
temperatures as strong high pressure combines with fresh snow and clear
skies aloft. Have generally undercut guidance for temps both Thu and
Fri with Fri morning shaping up to be one of the coldest mornings of
the year /subzero at KCI?/. Any precip with this weekend/s system to
hold off until later on Saturday.
.LONG TERM...(Saturday through Tuesday)
Issued at 412 AM CST WED FEB 25 2015
Models continue to advertise an active weather pattern for much of
the extended range forecast. Two main features of interest that will
be the driving forces for sensible weather across our area will be:
1) An upper level trough across the central Rockies 2) A surface
front that will sink south through the forecast area and stall south
of the area.
On Saturday, an upper level trough will be sinking slow south across
the central Rockies. Further east, across the eastern half of the
CONUS, the upper flow will become quasi-zonal. Several shortwave
impulses will eject out from the upper level trough and into the
local area. Cold air will already be in place on Saturday and
precipitation should begin as snow...spreading from west to east
through the afternoon. Snow will continue through Saturday night.
Sunday, a cold front will sink south through the area reinforcing
the cold air and continue snow chances. However, as we get into
Sunday night we begin to lose ice crystals in the snow growth
zone...especially across the southern CWA...and snow may mix with or
change over to sleet.
Model solutions begin to diverge in the Monday to Tuesday timeframe.
On Monday, model differences revolve around how quickly the cold
front begins to lift back north towards the forecast area. Although,
precipitation continues to look likely on Monday, P-Type is more in
question with the front lifting back northward. Model soundings
indicate the potential for freezing rain to the south a wintry mix
across the central CWA with the northern CWA remaining snow. Tuesday
the main concern will be the upper level trough across the Rockies.
The GFS is faster moving it through the area on Tuesday bringing
another round of snow to the forecast area. The EC is about 24 hours
slower in moving the trough eastward into the local area. This
solution would bring a lull in precipitation on Tuesday with another
round of precipitation back in on Wednesday. Have maintained a
blended solution through this timeframe until forecast details can
be fine tuned.
&&
.AVIATION...(For the 18Z TAFS through 18Z Thursday Afternoon)
Issued at 1125 AM CST WED FEB 25 2015
Strong cold front will drop through the region early this evening with
an area of rain/snow spreading into northern Missouri behind it. Most
accumulating snow will stay well to the northeast of the KC area,
mainly affecting CDJ and IRK areas, possibly down to DMO. For the STJ
and KC areas, a few rain/snow showers are possible for a few hours
behind the front but any snow accumulations will be under a half inch
with minimal impacts to air operations, although a rapid drop in
temperatures could freeze any water on runways. The bigger concern
will be the winds which may occasionally gust higher than 35 kt.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...WINTER WEATHER ADVISORY from 3 PM this afternoon to 6 AM CST
Thursday FOR MOZ003>008-014>017-023>025-032-033.
&&
$$
UPDATE...Hawblitzel
SHORT TERM...32
LONG TERM...73
AVIATION...Hawblitzel
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1005 AM CST Wed Feb 25 2015
.UPDATE...
Issued at 1005 AM CST WED FEB 25 2015
This morning`s model runs, including the short-term HRRR and RAP,
continue to trend a bit further east with the surface low track which
now looks to track from near Maryville to just west of Chillicothe to
near Boonville. Didn`t make any significant changes to snow amounts
to the east of the low track, still generally 2" to 4" across the
advisory area, but it now looks like anything more than 4" will be
just outside our CWA across southeast IA. With the surface low
tracking over Maryville, any advisory-level snows should fall just
east of Nodaway County so this county was removed from the winter
weather advisory.
To the west of the low track, any precipitation will be limited to a
short-window just behind a cold front which will track through later
this evening. This front will bring a rapid drop in temperatures so
that any precipitation that starts as rain should quickly be able to
switch to snow. Decent post-frontal convergence and shallow low-
level frontogenesis may still be able to squeeze out a quick sprinkle
or snow shower despite the recent runs of the RAP and HRRR keeping
these areas completely dry. However the odds of any snow accumulation
reaching an inch or more are low. Updated the forecast for the KC
metro and points south and west to keep snow amounts generally under
a half inch. The bigger concern for these areas will be potential
flash-freezing of any rain or melting snow that does fall, with
temperatures forecast to be dropping into the 20s across all areas by
midnight.
&&
.SHORT TERM...(Today through Friday)
Issued at 412 AM CST WED FEB 25 2015
Water vapor showing well anticipated shortwave trough dropping through
the northern Rockies this morning...with associated sfc reflection
now analyzed along the central Nebraska/South Dakota border. Out
ahead of the sfc low...latest sfc obs show a stationary boundary
extending east-southeast through southern Iowa into northern Illinois
and Indiana. With time today...main shortwave and sfc low will
continue tracking along this boundary before passing over the lower
Missouri Valley later tonight. As has been advertised in recent
days...region remains in the cross-hairs for accumulating snowfall
later tonight as system passes overhead. One would think that the
fcst would have been fairly easy this morning with us being so close
to event start time...but that could not be further from the truth as
latest 00z guidance has come in with a more northward track of the
main sfc low later tonight. With this being the case...our region stands
an excellent chance of warming quite a bit higher than previously
thought...which adds a fair amount of complexity to the going
forecast. Out ahead of the low...southwest downslope winds will
combine with modest warm air advection to allow temperatures to reach
the lower to middle 50s across west-central Missouri and eastern
Kansas to include the KC and STJ metros. To the east...a lingering
snowpack remains in place along and north of the Missouri River which
will likely result in a fairly impressive thermal gradient later this
afternoon. Meanwhile areas north of Route 36 also stand a decent
chance of warming up today as much of far northern Missouri also remains
snow free. In any event...warmer temps and the overall delay of the
system/s arrival by a few hours has resulted in changes to the fcst
to include snow total amounts.
As a result of the delayed arrival...latest models show precip
struggling to work into the area by 21z. With warmer temps in
place...precip will likely start out as rain across much of the
area...before cold air finally begins working into the region later
in the evening behind the main cold front. With limited winter precip
expected this afternoon...have elected to delay the winter weather
advisory start time until 21z this afternoon...and that may still be
a bit to early. In any event...models show main QPF max sliding
southeast over the area mainly between 00 and 06z tonight...with
precip gradually coming to an end from west to east during the early
morning hrs. Considering the amount of warming during the day...warm
ground temps should limit overall accumulations early on...before
precip rates increase heading into the early overnight hrs. In terms
of accumulations...expect maybe an inch in the greater KC area...with
even less across our eastern Kansas and our west-central Missouri
zones south of I-70. Further east where the heavier precip is
expected...have trimmed back on snowfall amounts slightly as fast
storm movement and delayed precip arrival time will likely lead to
slightly lower amounts. In general across the advisory area...expect
2-4" across most locations...however 3-5" will be possible north of
Kirksville before all is said and done. Cannot rule out a 6" report
up there but did not have enough confidence to even consider a
possible warning upgrade. As alluded to above...best accumulations
likely to occur after 00z...hence supporting the decision to slide
the advisory start time to the right.
Another factor to consider overnight will be the strong winds
with cold air advection following fropa. Current BUFKIT momentum
transfer tool output suggesting gusts in the mid to upper 30 kt range
later tonight. Combine this with any falling snow....blowing and
drifting will certainly be a possibility overnight.
Lingering light snow shwrs to come to an end by mid morning Thursday
as drier air and strong high pressure builds into the area. For the
remainder of the short term...focus will be on well below normal
temperatures as strong high pressure combines with fresh snow and clear
skies aloft. Have generally undercut guidance for temps both Thu and
Fri with Fri morning shaping up to be one of the coldest mornings of
the year /subzero at KCI?/. Any precip with this weekend/s system to
hold off until later on Saturday.
.LONG TERM...(Saturday through Tuesday)
Issued at 412 AM CST WED FEB 25 2015
Models continue to advertise an active weather pattern for much of
the extended range forecast. Two main features of interest that will
be the driving forces for sensible weather across our area will be:
1) An upper level trough across the central Rockies 2) A surface
front that will sink south through the forecast area and stall south
of the area.
On Saturday, an upper level trough will be sinking slow south across
the central Rockies. Further east, across the eastern half of the
CONUS, the upper flow will become quasi-zonal. Several shortwave
impulses will eject out from the upper level trough and into the
local area. Cold air will already be in place on Saturday and
precipitation should begin as snow...spreading from west to east
through the afternoon. Snow will continue through Saturday night.
Sunday, a cold front will sink south through the area reinforcing
the cold air and continue snow chances. However, as we get into
Sunday night we begin to lose ice crystals in the snow growth
zone...especially across the southern CWA...and snow may mix with or
change over to sleet.
Model solutions begin to diverge in the Monday to Tuesday timeframe.
On Monday, model differences revolve around how quickly the cold
front begins to lift back north towards the forecast area. Although,
precipitation continues to look likely on Monday, P-Type is more in
question with the front lifting back northward. Model soundings
indicate the potential for freezing rain to the south a wintry mix
across the central CWA with the northern CWA remaining snow. Tuesday
the main concern will be the upper level trough across the Rockies.
The GFS is faster moving it through the area on Tuesday bringing
another round of snow to the forecast area. The EC is about 24 hours
slower in moving the trough eastward into the local area. This
solution would bring a lull in precipitation on Tuesday with another
round of precipitation back in on Wednesday. Have maintained a
blended solution through this timeframe until forecast details can
be fine tuned.
&&
.AVIATION...(For the 12Z TAFS through 12Z Thursday Morning)
Issued at 520 AM CST WED FEB 25 2015
VFR conditions to continue much of the day with southwest winds
between 10-15 kts. By early evening...conditions will quickly
deteriorate to MVFR and eventually IFR and long anticipated storm
system moves overhead. Precip initially in the form of a RA/SN mix
will gradually change over to all SN as colder air filters into the
area. Terminals standing the best chance of seeing IFR VSBYs will be
STJ and MCI...with lower probabilities at remaining sites further south.
Precip will come to an end by 4z with low-end MVFR cigs remaining in
place through the duration of the fcst period. After fropa...winds
will quickly increase from the north by mid/late evening with north
winds gusting up to 35 kts overnight.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...WINTER WEATHER ADVISORY from 3 PM this afternoon to 6 AM CST
Thursday FOR MOZ003>008-014>017-023>025-032-033.
&&
$$
UPDATE...Hawblitzel
SHORT TERM...32
LONG TERM...73
AVIATION...32
AREA FORECAST DISCUSSION
NWS HASTINGS NE
353 PM CST WED FEB 25 2015
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 345 PM CST WED FEB 25 2015
LATEST RADAR SHOWS THE RAIN AND SNOW IS MOVING OUT OF THE FORECAST
AREA THIS AFTERNOON. THERE HAVE BEEN A FEW FLURRIES BEHIND THE MAIN
BAND...BUT EVEN THOSE ARE DIMINISHING THIS AFTERNOON. SURFACE
ANALYSIS HAS THE COLD FRONT ALREADY THROUGH THE FORECAST AREA AND
GUSTY NORTH WINDS ACROSS THE AREA. TEMPERATURES HAVE BEEN FALLING
FOR MUCH OF THE AREA THIS AFTERNOON.
MAIN QUESTION THIS AFTERNOON IS HOW QUICKLY THE PRECIPITATION WILL
MOVE OUT OF THE FORECAST AREA. THE RAP AND THE WRF BOTH INDICATE THE
PRECIPITATION SHOULD BE AN AFTERNOON EVENT AND BE DONE BEFORE THIS
EVENING. EVEN THE NAM AND THE GFS HAS IT ENDING BEFORE 00Z. WILL
START THE EVENING WITH A DRY FORECAST.
A SURFACE HIGH PRESSURE BUILDS IN THE DAKOTAS TONIGHT AND THURSDAY.
THIS WILL PUSH THE MOISTURE AND CLOUDS OUT OF THE AREA. SINCE THE
CENTER OF THE HIGH REMAINS TO THE NORTHEAST THROUGH THE
PERIOD...THERE WILL BE A FEW CLOUDS AROUND...BUT EXPECT CLOUDS TO
DIMINISH GRADUALLY LATE TONIGHT INTO THURSDAY.
THE COLD AIR HAS ALREADY STARTED TO MOVE INTO THE AREA THIS
AFTERNOON AND TEMPERATURES FOR MUCH OF THE AREA ARE COOLER NOW THAN
EARLIER. THE TEMPERATURES WILL CONTINUE TO PLUMMET TONIGHT WITH THE
DIMINISHING CLOUDS. THE COLD AIR REMAINS FIRMLY IN PLACE FOR
THURSDAY.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 345 PM CST WED FEB 25 2015
THE FOCUS OF THE LONG TERM FORECAST CENTERS AROUND PRECIPITATION
CHANCES OVER THE WEEKEND AND BEGINNING OF THE WORK WEEK AS WELL AS
BELOW NORMAL TEMPERATURES.
HEADING INTO THE LONG TERM...A DEEP UPPER LEVEL TROUGH WILL DIG
SOUTH ACROSS THE WESTERN COAST PROVIDING OUR WINTER WEATHER FOR THE
NEXT SEVERAL DAYS. THIS TROUGH WILL ALLOW MULTIPLE DISTURBANCES TO
TREK ACROSS THE CENTRAL PLAINS...WITH THE FIRST PASSING THROUGH
DURING THE WEEKEND TIMEFRAME AND THE SECOND HITTING MONDAY INTO
TUESDAY.
BY SATURDAY MORNING THE MAIN UPPER LEVEL LOW WILL BE POSITIONED
ALONG THE CALIFORNIA NEVADA BORDER WITH THE MID LEVEL LOW SLIGHTLY
EAST. THE FIRST ROUND OF MID LEVEL WAVES WILL BEGIN TO SLIDE THROUGH
THE PLAINS BY SATURDAY MORNING AHEAD OF THE PARENT LOW SYSTEM. IN
ADDITION TO THE WAVE...WARM AIR ADVECTION ACROSS THE PLAINS WILL
FUEL PLENTY OF MID LEVEL MOISTURE ACROSS THE REGION. WHILE THE GFS
IS STRONGER THAN THE ECMWF...BOTH MODEL SOLUTIONS SUGGEST GOOD
ISENTROPIC LIFT ESPECIALLY ACROSS KANSAS THROUGH THE WEEKEND.
FINALLY...A COLD FRONT WILL SLIDE THROUGH THE AREA SUNDAY MORNING
WITH AT LEAST SOME FRONTOGENETIC LIFT ALONG ITS BOUNDARY. ALTHOUGH
THIS IS NOT A MAJOR SYNOPTIC SETUP...BUT RATHER A MINOR
WAVE...SEVERAL KEY COMPONENTS ARE COMING TOGETHER TO FORM A DECENT
CHANCE FOR SNOW SATURDAY INTO SUNDAY MORNING. WITH MODEL AGREEMENT
LEANING TOWARDS BETTER LIFT OVER KANSAS...PLACED HIGHER AMOUNTS OVER
NORTH CENTRAL KANSAS. CURRENT MODEL TRENDS INDICATE THE POTENTIAL
FOR AT LEAST A COUPLE OF INCHES OF SNOW BY THE END OF THE WEEKEND
ACROSS NORTH CENTRAL KANSAS...POSSIBLY ADVISORY CRITERIA...WITH
LESSER AMOUNTS FARTHER NORTH.
THE NEXT SYSTEM SLIDES THROUGH MONDAY INTO TUESDAY...AND IS SOMEWHAT
MORE INTRIGUING. WHILE THE MAIN UPPER LEVEL LOW SLOWLY SHIFTS ACROSS
THE ROCKY MOUNTAINS...THE MID LEVEL LOW SURGES NORTHWARD ACROSS
NORTHERN NEBRASKA AND DAKOTAS. STRONG WARM AIR ADVECTION AND
SOUTHEASTERLY WINDS WILL BRING PLENTY OF MOISTURE AGAIN TO THE
CENTRAL PLAINS. ISENTROPIC LIFT IS BETTER IN BOTH THE GFS AND ECMWF
THAN THE WEEKEND STORM. AND ANOTHER COLD FRONT WILL DRAG ACROSS THE
CWA BY TUESDAY AFTERNOON. LOOKING AT ANOTHER ROUND OF SNOW FOR THE
FORECAST AREA. AT THIS TIME...ITS TOO EARLY TO DETERMINE
AMOUNTS...BUT RIGHT NOW MODELS FOCUS HEAVIER BANDS NORTH OF
INTERSTATE 80.
COLD TEMPERATURES CONTINUE THROUGHOUT THE LONG TERM...WITH AT LEAST
TWO SHOTS OF REINFORCING COLD AIR...AND LITTLE TO ANY WARM UPS. BOTH
COLD FRONTS...SUNDAY AND TUESDAY BRING VERY COLD 850 MB AIR TO THE
REGION...THE COLDER OF THE TWO ON TUESDAY. 850 TEMPERATURES DIP TO
NEAR 15 DEGREES BELOW BY WEDNESDAY AFTER THE COLD FRONTAL PASSAGE.
&&
.AVIATION...(FOR THE 18Z KGRI/KEAR TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1123 AM CST WED FEB 25 2015
THE FIRST BAND OF PRECIPITATION HAS MOVED THROUGH THE TERMINALS
BUT THERE IS A LITTLE BIT BEHIND THE MAIN BAND. TEMPERATURES HAVE
BEEN FALLING AND SO THERE MAY BE A LITTLE SPRINKLE OR FLURRIES FOR
A TIME THIS AFTERNOON. HAVE LEFT IT OUT OF KEAR...BUT THERE COULD
BE A STRAY FLURRY EARLY THIS AFTERNOON. THE WINDIEST PERIOD WILL
BE THIS AFTERNOON...BUT BREEZY CONDITIONS ARE EXPECTED THROUGH THE
PERIOD. LOW CLOUDS WILL MOVE OUT OF THE AREA OVERNIGHT.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...JCB
LONG TERM...SALTZMAN
AVIATION...JCB
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1133 AM CST WED FEB 25 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 355 AM CST WED FEB 25 2015
...ARCTIC AIR RETURNS WITH A VENGEANCE WITH FRONTAL PASSAGE
ACCOMPANIED BY POSSIBLE RAIN/SNOW SHWRS FOLLOWED BY HOWLING N
WINDS UP TO 50 MPH...
ALOFT: SEVERAL WEAK/SUBTLE SHORTWAVE TROFS WILL CROSS THE FCST
AREA THRU TONIGHT IN NW FLOW. THE LEAD TROF WILL BE THE POTENTIAL
WX- MAKER WHICH WILL MOVE THRU 15Z-00Z...ASSOCIATED WITH THE
PASSAGE OF THE SFC LOW.
SURFACE: AN ARCTIC COLD FRONT EXTENDED FROM HUDSON BAY THRU THE
GREAT LAKES ACROSS IA TO LOW PRES OVER SD AND THEN NW INTO CANADA.
THIS LOW WILL HEAD SE ACROSS NEB TODAY AND IN ITS WAKE THE FRONT
WILL SURGE S TODAY AND WILL BE S OF THE FCST AREA BY SUNSET.
ARCTIC HIGH PRES THEN BEGINS BUILDING IN TONIGHT FROM CANADA.
EARLY THIS MORNING: CLOUDS WILL CONT TO INCREASE FROM THE NW.
GENERALLY MILD WITH TEMPS AT OR ABOVE FRZG MOST LOCATIONS.
HAZARDS: N WINDS WILL GUST 45-50 MPH 12PM-12AM. DANGEROUS WIND
CHILLS DOWN TO -20F LATE TONIGHT...N OF I-80.
TODAY: NOT SURE HOW IT UNFOLDS. WE KNOW FOR SURE THAT THE
STEADIEST PRECIP WILL BE E OF THE FCST AREA...ON THE COLD SIDE OF
THE FRONT IN THE WAA. SPOTTY ECHOES HAVE BEEN INCREASE THRU THE
NIGHT SW OF THE LOW THRU THE BLACK HILLS INTO THE PANHANDLE.
UPSTREAM SOUNDINGS SHOW A LOT OF DRY AIR IN THE LOW-LVLS. SO FAR
HAVE ONLY SEEN ONE STATION REPORT SPRINKLES UPSTREAM.
OVERALL EXPECT A M/CLOUDY DAY OVER S-CNTRL NEB AND BECOMING
M/CLOUDY OVER N-CNTRL KS. MOST MESOSCALE MODELS SUGGEST A
NARROW/BROKEN BAND OF STRONGLY-FORCED SHWRS WILL DEVELOP ALONG THE
FRONT WHICH COULD BRIEFLY CHANGEOVER TO SNOW BEFORE ENDING...
PRIMARILY N OF HWY 6. PRECIP WILL INITIALLY STRUGGLE TO REACH THE
GROUND. THE ENVIRONMENT IS NOT FAVORABLE FOR MUCH MEASURABLE
PRECIP.
THE LOWEST CONFIDENCE PORTION OF THE FCST IS TEMPS. WE COULD BE
TOO COOL. MULTIPLE OVERNIGHT CYCLES OF THE RAP SUGGEST 50F UP TO
I-80 AND NEARING 60 OVER N-CNTRL KS. I COULD ONLY ENVISION THAT
HAPPENING WITH FULL SUN AND THAT IS NOT EXPECTED. USED CONSENSUS
OF HI-RES SHORT-TERM MODELS FOR HIGHS AND THEN NUDGED HIGHS MORE
INTO THE 50S OVER N-CNTRL KS IN COORDINATION WITH KS OFFICES.
TEMPS WILL FALL THIS AFTERNOON N OF I-80 BEHIND THE FRONT.
WINDS: BLENDED THE 18Z/00Z MAV MOS 50-50. N WINDS WILL HOWL...
GUSTING 45-50 MPH IN THE TIGHT PRES GRADIENT/CAA BEHIND THE LOW. 6
HR PRES RISES OF 12 MB ARE LIKELY.
TONIGHT: CLOUDY...WINDY AND TURNING VERY COLD. WINDS WILL BE
STRONGEST PRIOR TO MIDNIGHT. TEMPS PLUMMET INTO THE SINGLE DIGITS
OVER N-CNTRL NEB AND LINGERING WINDS WILL PUSH WIND CHILLS AS LOW
AS -20F.
CAA WILL RESULT IN SOME MODEST INSTABILITY IN THE LINGERING
STRATUS WHICH WILL COOL INTO THE IDEAL SNOW GROWTH LAYER. SO KEPT
THE MENTION OF FLURRIES FROM THE PREVIOUS FCST.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 504 AM CST WED FEB 25 2015
THE MAIN FORECAST CONCERN IS THE CHANCE FOR SNOW OVER THE WEEKEND
AND INTO EARLY NEXT WORK WEEK.
WE START OUT THE LONG TERM FORECAST THURSDAY WITH AN EXPANDING
SURFACE RIDGE BUILDING IN. MODEL SOUNDINGS INDICATE THAT WE COULD
HANG ON TO SOME STRATUS A LITTLE LONGER THAN WHAT OUR INITIALIZED
SUPERBLEND ADVERTISES AND I HAVE BUMPED UP SKY COVER. MODELS ARE
IN GOOD AGREEMENT WITH 850 MB TEMPERATURES IN THE -165 TO -20
RANGE FOR THURSDAY...WE WILL STRUGGLE TO GET HIGHS IN THE TEENS
FOR MOST AREAS. WE MAY MAKE IT TO AROUND 20 IN OUR SOUTH. I USED
THE NAM FOR HIGH TEMPERATURES...BUT THIS IS DEPENDING ON WIND
SPEEDS STAYING UP A BIT. GFS ACTUALLY INDICATES SOME AREA IN OUR
NORTHEAST NOT BREAKING INTO THE TEENS FOR HIGHS...AND THIS MAY
VERY WELL HAPPEN...ESPECIALLY IF WIND SPEED DROPS AND WE GET A
LITTLE MORE SKY COVER HANGING AROUND.
THE 1040 MB HIGH WILL BE CENTERED OVER THE NORTHERN PLAINS BY
THURSDAY EVENING AND WILL CONTINUE MOVING SOUTH SOUTHEAST.
THURSDAY WILL FEEL QUITE COLD. WIND CHILLS MAY BRIEFLY BREAK INTO
THE SINGLE DIGITS FOR THE AFTERNOON BEFORE MAKING ANOTHER DIVE.
WIND SPEED COULD BE JUST STRONG ENOUGH THURSDAY NIGHT TO KEEP WIND
CHILLS IN THE -15 TO -20 RANGE IN OUR NORTHEAST. WIND SPEEDS
SHOULD DIMINISH LATE AS THE CENTER OF THE SURFACE HIGH SLIDES
NEARER...MAYBE AS CLOSE AS EASTERN NEBRASKA. THIS WILL CAUSE WIND
TO DROP OFF QUITE A BIT AND WITH ANTICIPATED MOSTLY CLEAR SKY FOR
MUCH OF THE CWA...WE COULD WIND UP BEING BELOW ZERO FOR A
CONSIDERABLE PORTION OF THE CWA. ORD COULD REALLY TANK TO NEAR
-10. NUMERICAL MODELS ARE ALL TRENDING COLDER FOR THURSDAY
NIGHT/FRIDAY MORNING AND I HAVE CONTINUED THIS TREND. I BUMPED
DOWN TEMPERATURES CONSIDERABLY COMPARED TO SUPERBLEND
INITIALIZATION. WE MAY HOLD NEAR ZERO IN OUR SOUTH/SOUTHWEST WHERE
WE MAY HAVE A FEW MORE CLOUDS AROUND ALONG WITH SLIGHTLY STRONGER
WIND SPEED.
NUMERICAL MODELS ALL TEND TO KEEP US DRY FRIDAY/FRIDAY NIGHT FOR
THE MOST PART...WITH THE EXCEPTION OF PERHAPS SOME FLURRIES IN
ADVANCE OF THE NEXT WINTER SYSTEM ARRIVING FOR THE WEEKEND.
A POSITIVELY TILTED MEAN TROUGH DEVELOPS IN THE WESTERN UNITED
STATES AND LONG RANGE MODELS ARE CONSISTENT AND CONGRUENT WITH
THIS SYNOPTIC FEATURE. THIS SETS UP A COLD AND UNSETTLED PATTERN
FOR US WITH THE SOUTHERN STREAM SOUTHWEST FLOW AND IMPULSES OF
ENERGY FROM SATURDAY THROUGH MONDAY NIGHT THAT COULD GIVE US MORE
THAN ONE ROUND OF MEASURABLE SNOWFALL. FOR NOW...THE CURRENT TRACK
WOULD PLACE MORE SNOW CHANCES IN OUR SOUTHERN CWA...BUT AS WE ALL
KNOW...THINGS MAY TREND ONE WAY OR ANOTHER...ESPECIALLY AS WE ARE
3 TO 5 DAYS AWAY. I DID BUMP UP PRECIPITATION CHANCES A BIT MORE
FOR SATURDAY AND SATURDAY NIGHT AS MODELS CONTINUE TO PAINT
CONSIDERABLE QPF FOR US...ESPECIALLY IN OUR SOUTH. THIS STILL
LOOKS AT LEAST LIKE A POTENTIAL WINTER WEATHER ADVISORY SITUATION
...BUT WE STILL HAVE SOME TIME BEFORE THIS ARRIVES AND WE SHOULD
GET A BETTER HANDLE OF THIS WITH TIME.
I WENT CLOSER TO CONSRAW FOR HIGH TEMPERATURES FRIDAY INTO MONDAY
...WHICH WAS GENERALLY PRETTY CLOSE TO SUPERBLEND...EXCEPT FOR
MONDAY WHICH BUMPED TEMPERATURES DOWN A BIT FROM INITIALIZED
GRIDS. THIS WOULD MAKE SENSE...ESPECIALLY IF THERE ENDS UP BEING
SNOW ON THE GROUND. I DO NOT SEE AN END TO WELL BELOW NORMAL
TEMPERATURES ANYTIME SOON...WITH WELL BELOW TEMPERATURES EXPECTED
INTO EARLY MARCH UNDER THIS CONSISTENTLY COLD PATTERN.
&&
.AVIATION...(FOR THE 18Z KGRI/KEAR TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1123 AM CST WED FEB 25 2015
THE FIRST BAND OF PRECIPITATION HAS MOVED THROUGH THE TERMINALS
BUT THERE IS A LITTLE BIT BEHIND THE MAIN BAND. TEMPERATURES HAVE
BEEN FALLING AND SO THERE MAY BE A LITTLE SPRINKLE OR FLURRIES FOR
A TIME THIS AFTERNOON. HAVE LEFT IT OUT OF KEAR...BUT THERE COULD
BE A STRAY FLURRY EARLY THIS AFTERNOON. THE WINDIEST PERIOD WILL
BE THIS AFTERNOON...BUT BREEZY CONDITIONS ARE EXPECTED THROUGH THE
PERIOD. LOW CLOUDS WILL MOVE OUT OF THE AREA OVERNIGHT.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...HALBLAUB
LONG TERM...HEINLEIN
AVIATION...JCB
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1130 AM CST WED FEB 25 2015
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 216 AM CST WED FEB 25 2015
INITIAL CONCERN WILL BE TYPE AND EXTENT OF PRECIP AS SURFACE LOW
TRACKS ACROSS THE AREA TODAY. THEN COLD AND WINDY CONDITIONS WITH
SUBZERO WIND CHILLS APPROACHING CRITERIA THURSDAY MORNING. JUST
PLAIN COLD FRIDAY MORNING.
SURFACE LOW WAS LOCATED OVER SOUTH CENTRAL SOUTH DAKOATA AT 08Z
WITH PRIMARY BAND OF PRECIP FROM EASTERN SOUTH DAKOTA INTO
SOUTHWEST MINNESOTA AND NORTHWEST IOWA. BOTH THE HRRR AND RAP
SLOWER IN BRINGING THE PRECIP SHIELD SOUTH TODAY WITH PRIMARY BAND
STRETCHING ACROSS NORTHERN IOWA THROUGH THE MORNING. HAVE ADJUSTED
TIMING OF THE WINTER WEATHER ADVISORY TO ACCOUNT FOR THIS FEATURE
AND ALSO REMOVED THE TWO SOUTHWEST IOWA COUNTIES AS TEMPERATURES
ARE EXPECTED TO REMAIN ON THE WARM SIDE THERE FOR MOST OF THE DAY
WITH BETTER QPF EAST OF THE AREA.
HAVE TRENDED TEMPERATURES WARMER ACROSS THE SOUTH HALF OF THE AREA
AND BACKED OFF FURTHER ON PRECIP AND SNOW ACROSS THE SOUTH.
TEMPERATURES WILL BE TRICKY TODAY AND DEPEND ON TIMING OF THE COLD
AIR BEHIND THE FRONT THIS AFTERNOON AS THE LOW TRACKS ACROSS EAST
CENTRAL NEBRASKA TOWARD NORTHWEST MISSOURI. A PERIOD OF MIXED
PRECIP...WHICH COULD INCLUDE FREEZING RAIN...IS POSSIBLE FOR A
TIME THIS MORNING IN PARTS OF NORTHEAST NEBRASKA INTO WEST CENTRAL
IOWA BEFORE THE COLD AIR MOVES IN BEHIND THE FRONT. AMOUNTS SHOULD
BE LIGHT WITH LIMITED AREAL COVERAGE.
THE ARCTIC AIR SPREADS RAPIDLY SOUTH TONIGHT ALONG WITH GUSTY
NORTHWEST WINDS. SUBZERO WIND CHILLS ARE LIKELY ACROSS THE AREA BY
THURSDAY MORNING WITH NORTHERN COUNTIES APPROACHING ADVISORY
CRITERIA. WILL COVER THE COLD IN HWO FOR NOW BUT ADVISORY LOOKS
LIKELY IN LATER FORECASTS. WINDY AND COLD CONDITIONS WILL EXTEND
THROUGH THE DAY ON THURSDAY WITH WINDS DIMINISHING THURSDAY
EVENING. TEMPERATURES ARE EXPECTED TO PLUNGE BELOW ZERO THURSDAY
NIGHT AS HIGH SETTLES OVER THE AREA AND WINDS BECOME LIGHT. SLOW
WARMING???? ON FRIDAY AS HIGH MOVES EAST.
.LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY)
ISSUED AT 216 AM CST WED FEB 25 2015
LITTLE CHANGE TO GENERAL TRENDS. WEEKEND SYSTEM STILL KEEPS MAIN
PRECIP AXIS TO THE SOUTH WITH LIGHTER AMOUNTS FOR THE SOUTH HALF
OF THE CWA. MORE SIGNIFICANT SNOW POSSIBLE MONDAY INTO TUESDAY AS
MAIN WAVE COMES INTO THE PLAINS REGION.
&&
.AVIATION...(18Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 1123 AM CST WED FEB 25 2015
ACTIVE FIRST FEW HOURS OF TAF PERIOD...THEN CONDITIONS WILL BEGIN
TO SLOWLY IMPROVE. KOFK...BAND OF SNOW IS ABOUT THROUGH THE SITE.
MVFR CIGS ARE EXPECTED THROUGH 00Z THEN CONDITIONS WILL CONTINUE
TO IMPROVE. KOMA...FRONT IS JUST ABOUT TO THE SITE AS IS THE
BEGINNING EDGE OF PCPN. RAIN EXPECTED INITIALLY WITH A CHANGE OVER
TO RA/SN FOR AN HOUR OR SO BEFORE THE TRANSITION OVER TO ALL SNOW.
THE SNOW SHOULD BE BRIEF...ONLY AN HOUR...WITH A FEW FLURRIES
LINGERING INTO THE LATER PART OF THE AFTERNOON AND DRYING OUT
THEREAFTER. CIGS SHOULD REMAIN MVFR INTO THE EVENING HOURS. KLNK...FRONT
EDGE OF PCPN BAND IS ALMOST TO THE SITE WITH LIGHT RAIN EXPECTED.
THERE MAY BE A BRIEF MIX OF RA/SN MID AFTERNOON. THIS SHOULD BE
SHORT LIVED AND OUT OF THE AREA LATE THIS AFTERNOON WITH
CONDITIONS IMPROVING THEREAFTER. FOR ALL SITES...GUSTY
NORTH/NORTHWEST WINDS BEHIND THE FRONT ARE EXPECTED TO REMAIN
THROUGH THE OVERNIGHT.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...WINTER WEATHER ADVISORY UNTIL 8 PM CST THIS EVENING FOR IAZ055-
056.
WINTER WEATHER ADVISORY UNTIL 8 PM CST THIS EVENING FOR IAZ069.
WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR IAZ043.
&&
$$
SHORT TERM...FOBERT
LONG TERM...FOBERT
AVIATION...KERN
AREA FORECAST DISCUSSION
NWS HASTINGS NE
534 AM CST WED FEB 25 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 355 AM CST WED FEB 25 2015
...ARCTIC AIR RETURNS WITH A VENGEANCE WITH FRONTAL PASSAGE
ACCOMPANIED BY POSSIBLE RAIN/SNOW SHWRS FOLLOWED BY HOWLING N
WINDS UP TO 50 MPH...
ALOFT: SEVERAL WEAK/SUBTLE SHORTWAVE TROFS WILL CROSS THE FCST
AREA THRU TONIGHT IN NW FLOW. THE LEAD TROF WILL BE THE POTENTIAL
WX- MAKER WHICH WILL MOVE THRU 15Z-00Z...ASSOCIATED WITH THE
PASSAGE OF THE SFC LOW.
SURFACE: AN ARCTIC COLD FRONT EXTENDED FROM HUDSON BAY THRU THE
GREAT LAKES ACROSS IA TO LOW PRES OVER SD AND THEN NW INTO CANADA.
THIS LOW WILL HEAD SE ACROSS NEB TODAY AND IN ITS WAKE THE FRONT
WILL SURGE S TODAY AND WILL BE S OF THE FCST AREA BY SUNSET.
ARCTIC HIGH PRES THEN BEGINS BUILDING IN TONIGHT FROM CANADA.
EARLY THIS MORNING: CLOUDS WILL CONT TO INCREASE FROM THE NW.
GENERALLY MILD WITH TEMPS AT OR ABOVE FRZG MOST LOCATIONS.
HAZARDS: N WINDS WILL GUST 45-50 MPH 12PM-12AM. DANGEROUS WIND
CHILLS DOWN TO -20F LATE TONIGHT...N OF I-80.
TODAY: NOT SURE HOW IT UNFOLDS. WE KNOW FOR SURE THAT THE
STEADIEST PRECIP WILL BE E OF THE FCST AREA...ON THE COLD SIDE OF
THE FRONT IN THE WAA. SPOTTY ECHOES HAVE BEEN INCREASE THRU THE
NIGHT SW OF THE LOW THRU THE BLACK HILLS INTO THE PANHANDLE.
UPSTREAM SOUNDINGS SHOW A LOT OF DRY AIR IN THE LOW-LVLS. SO FAR
HAVE ONLY SEEN ONE STATION REPORT SPRINKLES UPSTREAM.
OVERALL EXPECT A M/CLOUDY DAY OVER S-CNTRL NEB AND BECOMING
M/CLOUDY OVER N-CNTRL KS. MOST MESOSCALE MODELS SUGGEST A
NARROW/BROKEN BAND OF STRONGLY-FORCED SHWRS WILL DEVELOP ALONG THE
FRONT WHICH COULD BRIEFLY CHANGEOVER TO SNOW BEFORE ENDING...
PRIMARILY N OF HWY 6. PRECIP WILL INITIALLY STRUGGLE TO REACH THE
GROUND. THE ENVIRONMENT IS NOT FAVORABLE FOR MUCH MEASURABLE
PRECIP.
THE LOWEST CONFIDENCE PORTION OF THE FCST IS TEMPS. WE COULD BE
TOO COOL. MULTIPLE OVERNIGHT CYCLES OF THE RAP SUGGEST 50F UP TO
I-80 AND NEARING 60 OVER N-CNTRL KS. I COULD ONLY ENVISION THAT
HAPPENING WITH FULL SUN AND THAT IS NOT EXPECTED. USED CONSENSUS
OF HI-RES SHORT-TERM MODELS FOR HIGHS AND THEN NUDGED HIGHS MORE
INTO THE 50S OVER N-CNTRL KS IN COORDINATION WITH KS OFFICES.
TEMPS WILL FALL THIS AFTERNOON N OF I-80 BEHIND THE FRONT.
WINDS: BLENDED THE 18Z/00Z MAV MOS 50-50. N WINDS WILL HOWL...
GUSTING 45-50 MPH IN THE TIGHT PRES GRADIENT/CAA BEHIND THE LOW. 6
HR PRES RISES OF 12 MB ARE LIKELY.
TONIGHT: CLOUDY...WINDY AND TURNING VERY COLD. WINDS WILL BE
STRONGEST PRIOR TO MIDNIGHT. TEMPS PLUMMET INTO THE SINGLE DIGITS
OVER N-CNTRL NEB AND LINGERING WINDS WILL PUSH WIND CHILLS AS LOW
AS -20F.
CAA WILL RESULT IN SOME MODEST INSTABILITY IN THE LINGERING
STRATUS WHICH WILL COOL INTO THE IDEAL SNOW GROWTH LAYER. SO KEPT
THE MENTION OF FLURRIES FROM THE PREVIOUS FCST.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 504 AM CST WED FEB 25 2015
THE MAIN FORECAST CONCERN IS THE CHANCE FOR SNOW OVER THE WEEKEND
AND INTO EARLY NEXT WORK WEEK.
WE START OUT THE LONG TERM FORECAST THURSDAY WITH AN EXPANDING
SURFACE RIDGE BUILDING IN. MODEL SOUNDINGS INDICATE THAT WE COULD
HANG ON TO SOME STRATUS A LITTLE LONGER THAN WHAT OUR INITIALIZED
SUPERBLEND ADVERTISES AND I HAVE BUMPED UP SKY COVER. MODELS ARE
IN GOOD AGREEMENT WITH 850 MB TEMPERATURES IN THE -165 TO -20
RANGE FOR THURSDAY...WE WILL STRUGGLE TO GET HIGHS IN THE TEENS
FOR MOST AREAS. WE MAY MAKE IT TO AROUND 20 IN OUR SOUTH. I USED
THE NAM FOR HIGH TEMPERATURES...BUT THIS IS DEPENDING ON WIND
SPEEDS STAYING UP A BIT. GFS ACTUALLY INDICATES SOME AREA IN OUR
NORTHEAST NOT BREAKING INTO THE TEENS FOR HIGHS...AND THIS MAY
VERY WELL HAPPEN...ESPECIALLY IF WIND SPEED DROPS AND WE GET A
LITTLE MORE SKY COVER HANGING AROUND.
THE 1040 MB HIGH WILL BE CENTERED OVER THE NORTHERN PLAINS BY
THURSDAY EVENING AND WILL CONTINUE MOVING SOUTH SOUTHEAST.
THURSDAY WILL FEEL QUITE COLD. WIND CHILLS MAY BRIEFLY BREAK INTO
THE SINGLE DIGITS FOR THE AFTERNOON BEFORE MAKING ANOTHER DIVE.
WIND SPEED COULD BE JUST STRONG ENOUGH THURSDAY NIGHT TO KEEP WIND
CHILLS IN THE -15 TO -20 RANGE IN OUR NORTHEAST. WIND SPEEDS
SHOULD DIMINISH LATE AS THE CENTER OF THE SURFACE HIGH SLIDES
NEARER...MAYBE AS CLOSE AS EASTERN NEBRASKA. THIS WILL CAUSE WIND
TO DROP OFF QUITE A BIT AND WITH ANTICIPATED MOSTLY CLEAR SKY FOR
MUCH OF THE CWA...WE COULD WIND UP BEING BELOW ZERO FOR A
CONSIDERABLE PORTION OF THE CWA. ORD COULD REALLY TANK TO NEAR
-10. NUMERICAL MODELS ARE ALL TRENDING COLDER FOR THURSDAY
NIGHT/FRIDAY MORNING AND I HAVE CONTINUED THIS TREND. I BUMPED
DOWN TEMPERATURES CONSIDERABLY COMPARED TO SUPERBLEND
INITIALIZATION. WE MAY HOLD NEAR ZERO IN OUR SOUTH/SOUTHWEST WHERE
WE MAY HAVE A FEW MORE CLOUDS AROUND ALONG WITH SLIGHTLY STRONGER
WIND SPEED.
NUMERICAL MODELS ALL TEND TO KEEP US DRY FRIDAY/FRIDAY NIGHT FOR
THE MOST PART...WITH THE EXCEPTION OF PERHAPS SOME FLURRIES IN
ADVANCE OF THE NEXT WINTER SYSTEM ARRIVING FOR THE WEEKEND.
A POSITIVELY TILTED MEAN TROUGH DEVELOPS IN THE WESTERN UNITED
STATES AND LONG RANGE MODELS ARE CONSISTENT AND CONGRUENT WITH
THIS SYNOPTIC FEATURE. THIS SETS UP A COLD AND UNSETTLED PATTERN
FOR US WITH THE SOUTHERN STREAM SOUTHWEST FLOW AND IMPULSES OF
ENERGY FROM SATURDAY THROUGH MONDAY NIGHT THAT COULD GIVE US MORE
THAN ONE ROUND OF MEASURABLE SNOWFALL. FOR NOW...THE CURRENT TRACK
WOULD PLACE MORE SNOW CHANCES IN OUR SOUTHERN CWA...BUT AS WE ALL
KNOW...THINGS MAY TREND ONE WAY OR ANOTHER...ESPECIALLY AS WE ARE
3 TO 5 DAYS AWAY. I DID BUMP UP PRECIPITATION CHANCES A BIT MORE
FOR SATURDAY AND SATURDAY NIGHT AS MODELS CONTINUE TO PAINT
CONSIDERABLE QPF FOR US...ESPECIALLY IN OUR SOUTH. THIS STILL
LOOKS AT LEAST LIKE A POTENTIAL WINTER WEATHER ADVISORY SITUATION
...BUT WE STILL HAVE SOME TIME BEFORE THIS ARRIVES AND WE SHOULD
GET A BETTER HANDLE OF THIS WITH TIME.
I WENT CLOSER TO CONSRAW FOR HIGH TEMPERATURES FRIDAY INTO MONDAY
...WHICH WAS GENERALLY PRETTY CLOSE TO SUPERBLEND...EXCEPT FOR
MONDAY WHICH BUMPED TEMPERATURES DOWN A BIT FROM INITIALIZED
GRIDS. THIS WOULD MAKE SENSE...ESPECIALLY IF THERE ENDS UP BEING
SNOW ON THE GROUND. I DO NOT SEE AN END TO WELL BELOW NORMAL
TEMPERATURES ANYTIME SOON...WITH WELL BELOW TEMPERATURES EXPECTED
INTO EARLY MARCH UNDER THIS CONSISTENTLY COLD PATTERN.
&&
.AVIATION...(FOR THE 12Z KGRI/KEAR TAFS THROUGH 12Z THU MORNING)
ISSUED AT 534 AM CST WED FEB 25 2015
TODAY: MULTI-LAYERED VFR CLOUDS WILL GRADUALLY DESCEND FROM 10K FT
WITH MVFR CIGS EXPECTED BY 18Z WITH PASSAGE OF A COLD FRONT. SOME
VFR SPRINKLES...AND POSSIBLY SOME RA/SN SHWRS WILL BE POSSIBLE...
ESPECIALLY IN THE 18Z-21Z TIME FRAME. THE CERTAINTY OF PRECIP
REDUCING THE VSBY TO MVFR OR LOWER IS NOT AS HIGH AS EARLIER. SO
WHILE THERE COULD BE A BRIEF PERIOD OF MVFR/IFR SN...CONFIDENCE IS
NO LONGER HIGH ENOUGH TO HAVE A LOW VSBY IN THE TAF. WATCH FOR
POSSIBLE AMENDMENTS AS WE MONITOR RADAR TRENDS AND UPSTREAM OBS.
WINDS WILL SHIFT TO N AND GUST 35-42 KTS BEHIND THE FRONT...
ESPECIALLY AFTER 20Z. CONFIDENCE: MEDIUM
TONIGHT: STRONG N WINDS CONT BUT GRADUALLY DECREASE BEGINNING
06Z. MVFR CIGS WILL EVENTUALLY BECOME SCT. CONFIDENCE: MEDIUM
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...HALBLAUB
LONG TERM...HEINLEIN
AVIATION...HALBLAUB
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
532 AM CST WED FEB 25 2015
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 216 AM CST WED FEB 25 2015
INITIAL CONCERN WILL BE TYPE AND EXTENT OF PRECIP AS SURFACE LOW
TRACKS ACROSS THE AREA TODAY. THEN COLD AND WINDY CONDITIONS WITH
SUBZERO WIND CHILLS APPROACHING CRITERIA THURSDAY MORNING. JUST
PLAIN COLD FRIDAY MORNING.
SURFACE LOW WAS LOCATED OVER SOUTH CENTRAL SOUTH DAKOATA AT 08Z
WITH PRIMARY BAND OF PRECIP FROM EASTERN SOUTH DAKOTA INTO
SOUTHWEST MINNESOTA AND NORTHWEST IOWA. BOTH THE HRRR AND RAP
SLOWER IN BRINGING THE PRECIP SHIELD SOUTH TODAY WITH PRIMARY BAND
STRETCHING ACROSS NORTHERN IOWA THROUGH THE MORNING. HAVE ADJUSTED
TIMING OF THE WINTER WEATHER ADVISORY TO ACCOUNT FOR THIS FEATURE
AND ALSO REMOVED THE TWO SOUTHWEST IOWA COUNTIES AS TEMPERATURES
ARE EXPECTED TO REMAIN ON THE WARM SIDE THERE FOR MOST OF THE DAY
WITH BETTER QPF EAST OF THE AREA.
HAVE TRENDED TEMPERATURES WARMER ACROSS THE SOUTH HALF OF THE AREA
AND BACKED OFF FURTHER ON PRECIP AND SNOW ACROSS THE SOUTH.
TEMPERATURES WILL BE TRICKY TODAY AND DEPEND ON TIMING OF THE COLD
AIR BEHIND THE FRONT THIS AFTERNOON AS THE LOW TRACKS ACROSS EAST
CENTRAL NEBRASKA TOWARD NORTHWEST MISSOURI. A PERIOD OF MIXED
PRECIP...WHICH COULD INCLUDE FREEZING RAIN...IS POSSIBLE FOR A
TIME THIS MORNING IN PARTS OF NORTHEAST NEBRASKA INTO WEST CENTRAL
IOWA BEFORE THE COLD AIR MOVES IN BEHIND THE FRONT. AMOUNTS SHOULD
BE LIGHT WITH LIMITED AREAL COVERAGE.
THE ARCTIC AIR SPREADS RAPIDLY SOUTH TONIGHT ALONG WITH GUSTY
NORTHWEST WINDS. SUBZERO WIND CHILLS ARE LIKELY ACROSS THE AREA BY
THURSDAY MORNING WITH NORTHERN COUNTIES APPROACHING ADVISORY
CRITERIA. WILL COVER THE COLD IN HWO FOR NOW BUT ADVISORY LOOKS
LIKELY IN LATER FORECASTS. WINDY AND COLD CONDITIONS WILL EXTEND
THROUGH THE DAY ON THURSDAY WITH WINDS DIMINISHING THURSDAY
EVENING. TEMPERATURES ARE EXPECTED TO PLUNGE BELOW ZERO THURSDAY
NIGHT AS HIGH SETTLES OVER THE AREA AND WINDS BECOME LIGHT. SLOW
WARMING???? ON FRIDAY AS HIGH MOVES EAST.
.LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY)
ISSUED AT 216 AM CST WED FEB 25 2015
LITTLE CHANGE TO GENERAL TRENDS. WEEKEND SYSTEM STILL KEEPS MAIN
PRECIP AXIS TO THE SOUTH WITH LIGHTER AMOUNTS FOR THE SOUTH HALF
OF THE CWA. MORE SIGNIFICANT SNOW POSSIBLE MONDAY INTO TUESDAY AS
MAIN WAVE COMES INTO THE PLAINS REGION.
&&
.AVIATION...(12Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 524 AM CST WED FEB 25 2015
SFC CDFNT WILL MOV SOUTHEAST THRU ALL 3 TAF SITES THROUGH EARLY
AFTERNOON SWITCHING WINDS TO THE NORTH AND NORTHWEST...WITH SPEEDS
INCREASING ALONG WITH GUSTS THROUGH THE END OF THE PERIOD. BEHIND
THE COLD FRONT THERE MAY BE AN HOUR OR TWO OF -RA AT KOFK/KLNK AND
A MIX OF RA/SN AT KOMA. SOME MVFR VISBY IS POSSIBLE FOR AN HOUR OR
TWO AT KOMA WITH THE MIX. WE DO EXPECT MVFR CIGS AT ALL 3 SITES
FROM LATE MRNG THROUGH THE AFTERNOON LIFTING TO VFR OVERNIGHT.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR NEZ015-
034.
IA...WINTER WEATHER ADVISORY UNTIL 8 PM CST THIS EVENING FOR IAZ055-
056.
WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR IAZ043.
WINTER WEATHER ADVISORY FROM 2 PM THIS AFTERNOON TO 8 PM CST
THIS EVENING FOR IAZ069.
&&
$$
SHORT TERM...FOBERT
LONG TERM...FOBERT
AVIATION...BOUSTEAD
AREA FORECAST DISCUSSION
NWS HASTINGS NE
505 AM CST WED FEB 25 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 355 AM CST WED FEB 25 2015
...ARCTIC AIR RETURNS WITH A VENGEANCE WITH FRONTAL PASSAGE
ACCOMPANIED BY POSSIBLE RAIN/SNOW SHWRS FOLLOWED BY HOWLING N
WINDS UP TO 50 MPH...
ALOFT: SEVERAL WEAK/SUBTLE SHORTWAVE TROFS WILL CROSS THE FCST
AREA THRU TONIGHT IN NW FLOW. THE LEAD TROF WILL BE THE POTENTIAL
WX- MAKER WHICH WILL MOVE THRU 15Z-00Z...ASSOCIATED WITH THE
PASSAGE OF THE SFC LOW.
SURFACE: AN ARCTIC COLD FRONT EXTENDED FROM HUDSON BAY THRU THE
GREAT LAKES ACROSS IA TO LOW PRES OVER SD AND THEN NW INTO CANADA.
THIS LOW WILL HEAD SE ACROSS NEB TODAY AND IN ITS WAKE THE FRONT
WILL SURGE S TODAY AND WILL BE S OF THE FCST AREA BY SUNSET.
ARCTIC HIGH PRES THEN BEGINS BUILDING IN TONIGHT FROM CANADA.
EARLY THIS MORNING: CLOUDS WILL CONT TO INCREASE FROM THE NW.
GENERALLY MILD WITH TEMPS AT OR ABOVE FRZG MOST LOCATIONS.
HAZARDS: N WINDS WILL GUST 45-50 MPH 12PM-12AM. DANGEROUS WIND
CHILLS DOWN TO -20F LATE TONIGHT...N OF I-80.
TODAY: NOT SURE HOW IT UNFOLDS. WE KNOW FOR SURE THAT THE
STEADIEST PRECIP WILL BE E OF THE FCST AREA...ON THE COLD SIDE OF
THE FRONT IN THE WAA. SPOTTY ECHOES HAVE BEEN INCREASE THRU THE
NIGHT SW OF THE LOW THRU THE BLACK HILLS INTO THE PANHANDLE.
UPSTREAM SOUNDINGS SHOW A LOT OF DRY AIR IN THE LOW-LVLS. SO FAR
HAVE ONLY SEEN ONE STATION REPORT SPRINKLES UPSTREAM.
OVERALL EXPECT A M/CLOUDY DAY OVER S-CNTRL NEB AND BECOMING
M/CLOUDY OVER N-CNTRL KS. MOST MESOSCALE MODELS SUGGEST A
NARROW/BROKEN BAND OF STRONGLY-FORCED SHWRS WILL DEVELOP ALONG THE
FRONT WHICH COULD BRIEFLY CHANGEOVER TO SNOW BEFORE ENDING...
PRIMARILY N OF HWY 6. PRECIP WILL INITIALLY STRUGGLE TO REACH THE
GROUND. THE ENVIRONMENT IS NOT FAVORABLE FOR MUCH MEASURABLE
PRECIP.
THE LOWEST CONFIDENCE PORTION OF THE FCST IS TEMPS. WE COULD BE
TOO COOL. MULTIPLE OVERNIGHT CYCLES OF THE RAP SUGGEST 50F UP TO
I-80 AND NEARING 60 OVER N-CNTRL KS. I COULD ONLY ENVISION THAT
HAPPENING WITH FULL SUN AND THAT IS NOT EXPECTED. USED CONSENSUS
OF HI-RES SHORT-TERM MODELS FOR HIGHS AND THEN NUDGED HIGHS MORE
INTO THE 50S OVER N-CNTRL KS IN COORDINATION WITH KS OFFICES.
TEMPS WILL FALL THIS AFTERNOON N OF I-80 BEHIND THE FRONT.
WINDS: BLENDED THE 18Z/00Z MAV MOS 50-50. N WINDS WILL HOWL...
GUSTING 45-50 MPH IN THE TIGHT PRES GRADIENT/CAA BEHIND THE LOW. 6
HR PRES RISES OF 12 MB ARE LIKELY.
TONIGHT: CLOUDY...WINDY AND TURNING VERY COLD. WINDS WILL BE
STRONGEST PRIOR TO MIDNIGHT. TEMPS PLUMMET INTO THE SINGLE DIGITS
OVER N-CNTRL NEB AND LINGERING WINDS WILL PUSH WIND CHILLS AS LOW
AS -20F.
CAA WILL RESULT IN SOME MODEST INSTABILITY IN THE LINGERING
STRATUS WHICH WILL COOL INTO THE IDEAL SNOW GROWTH LAYER. SO KEPT
THE MENTION OF FLURRIES FROM THE PREVIOUS FCST.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 504 AM CST WED FEB 25 2015
THE MAIN FORECAST CONCERN IS THE CHANCE FOR SNOW OVER THE WEEKEND
AND INTO EARLY NEXT WORK WEEK.
WE START OUT THE LONG TERM FORECAST THURSDAY WITH AN EXPANDING
SURFACE RIDGE BUILDING IN. MODEL SOUNDINGS INDICATE THAT WE COULD
HANG ON TO SOME STRATUS A LITTLE LONGER THAN WHAT OUR INITIALIZED
SUPERBLEND ADVERTISES AND I HAVE BUMPED UP SKY COVER. MODELS ARE IN
GOOD AGREEMENT WITH 850 MB TEMPERATURES IN THE -165 TO -20 RANGE FOR
THURSDAY...WE WILL STRUGGLE TO GET HIGHS IN THE TEENS FOR MOST
AREAS. WE MAY MAKE IT TO AROUND 20 IN OUR SOUTH. I USED THE NAM FOR
HIGH TEMPERATURES...BUT THIS IS DEPENDING ON WIND SPEEDS STAYING UP
A BIT. GFS ACTUALLY INDICATES SOME AREA IN OUR NORTHEAST NOT
BREAKING INTO THE TEENS FOR HIGHS...AND THIS MAY VERY WELL
HAPPEN...ESPECIALLY IF WIND SPEED DROPS AND WE GET A LITTLE MORE SKY
COVER HANGING AROUND.
THE 1040 MB HIGH WILL BE CENTERED OVER THE NORTHERN PLAINS BY
THURSDAY EVENING AND WILL CONTINUE MOVING SOUTH SOUTHEAST. THURSDAY
WILL FEEL QUITE COLD. WIND CHILLS MAY BRIEFLY BREAK INTO THE SINGLE
DIGITS FOR THE AFTERNOON BEFORE MAKING ANOTHER DIVE. WIND SPEED
COULD BE JUST STRONG ENOUGH THURSDAY NIGHT TO KEEP WIND CHILLS IN
THE -15 TO -20 RANGE IN OUR NORTHEAST. WIND SPEEDS SHOULD DIMINISH
LATE AS THE CENTER OF THE SURFACE HIGH SLIDES NEARER...MAYBE AS
CLOSE AS EASTERN NEBRASKA. THIS WILL CAUSE WIND TO DROP OFF QUITE A
BIT AND WITH ANTICIPATED MOSTLY CLEAR SKY FOR MUCH OF THE CWA...WE
COULD WIND UP BEING BELOW ZERO FOR A CONSIDERABLE PORTION OF THE
CWA. ORD COULD REALLY TANK TO NEAR -10. NUMERICAL MODELS ARE ALL
TRENDING COLDER FOR THURSDAY NIGHT/FRIDAY MORNING AND I HAVE
CONTINUED THIS TREND. I BUMPED DOWN TEMPERATURES CONSIDERABLY
COMPARED TO SUPERBLEND INITIALIZATION. WE MAY HOLD NEAR ZERO IN OUR
SOUTH/SOUTHWEST WHERE WE MAY HAVE A FEW MORE CLOUDS AROUND ALONG
WITH SLIGHTLY STRONGER WIND SPEED.
NUMERICAL MODELS ALL TEND TO KEEP US DRY FRIDAY/FRIDAY NIGHT FOR THE
MOST PART...WITH THE EXCEPTION OF PERHAPS SOME FLURRIES IN ADVANCE
OF THE NEXT WINTER SYSTEM ARRIVING FOR THE WEEKEND.
A POSITIVELY TILTED MEAN TROUGH DEVELOPS IN THE WESTERN UNITED
STATES AND LONG RANGE MODELS ARE CONSISTENT AND CONGRUENT WITH THIS
SYNOPTIC FEATURE. THIS SETS UP A COLD AND UNSETTLED PATTERN FOR US
WITH THE SOUTHERN STREAM SOUTHWEST FLOW AND IMPULSES OF ENERGY FROM
SATURDAY THROUGH MONDAY NIGHT THAT COULD GIVE US MORE THAN ONE ROUND
OF MEASURABLE SNOWFALL. FOR NOW...THE CURRENT TRACK WOULD PLACE MORE
SNOW CHANCES IN OUR SOUTHERN CWA...BUT AS WE ALL KNOW...THINGS MAY
TREND ONE WAY OR ANOTHER...ESPECIALLY AS WE ARE 3 TO 5 DAYS AWAY. I
DID BUMP UP PRECIPITATION CHANCES A BIT MORE FOR SATURDAY AND
SATURDAY NIGHT AS MODELS CONTINUE TO PAINT CONSIDERABLE QPF FOR
US...ESPECIALLY IN OUR SOUTH. THIS STILL LOOKS AT LEAST LIKE A
POTENTIAL WINTER WEATHER ADVISORY SITUATION...BUT WE STILL HAVE SOME
TIME BEFORE THIS ARRIVES AND WE SHOULD GET A BETTER HANDLE OF THIS
WITH TIME.
I WENT CLOSER TO CONSRAW FOR HIGH TEMPERATURES FRIDAY INTO
MONDAY...WHICH WAS GENERALLY PRETTY CLOSE TO SUPERBLEND...EXCEPT FOR
MONDAY WHICH BUMPED TEMPERATURES DOWN A BIT FROM INITIALIZED GRIDS.
THIS WOULD MAKE SENSE...ESPECIALLY IF THERE ENDS UP BEING SNOW ON
THE GROUND. I DO NOT SEE AN END TO WELL BELOW NORMAL TEMPERATURES
ANYTIME SOON...WITH WELL BELOW TEMPERATURES EXPECTED INTO EARLY
MARCH UNDER THIS CONSISTENTLY COLD PATTERN.
&&
.AVIATION...(FOR THE 06Z KGRI/KEAR TAFS THROUGH 06Z WED NIGHT)
ISSUED AT 1159 PM CST TUE FEB 24 2015
REST OF TONIGHT: MULTI-LAYERED VFR MID-LVL CIGS WILL OVERTAKE THE
TERMINALS FROM THE N...REMAINING AT OR ABOVE 10K FT. SSW WINDS
JUST UNDER 10 KTS. THERE MAY BE SOME MARGINAL LLWS BASED ON WINDS
FROM OUR RADAR AT 400 FT...BUT THESE WINDS MAY BE OVERDONE.
CONFIDENCE: HIGH
TUE: VFR CIGS LOWER TO AROUND 3500 FT. COLD FRONT PASSES THE
TERMINALS AROUND 18Z WITH A BRIEF BURST OF POSSIBLY IFR SNOW.
THERE IS UNCERTAINTY IN THE INTENSITY OF THE SNOW. IF THE WORST
CASE OCCURS...ANY ACCUM WOULD BE LESS THAN 1 INCH. MVFR CIGS MOVE
IN AFTER FRONTAL PASSAGE AND N WIND WILL GUST TO 35 KTS...WITH A
ONE-TIME PKWND OF 40 KTS POSSIBLE. CONFIDENCE: MEDIUM
TUE EVE: MVFR CIGS REMAIN. N WINDS WILL BE GRADUALLY DECREASING.
CONFIDENCE: MEDIUM
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...HALBLAUB
LONG TERM...HEINLEIN
AVIATION...HALBLAUB
AREA FORECAST DISCUSSION
NWS HASTINGS NE
355 AM CST WED FEB 25 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 355 AM CST WED FEB 25 2015
...ARCTIC AIR RETURNS WITH A VENGEANCE WITH FRONTAL PASSAGE
ACCOMPANIED BY POSSIBLE RAIN/SNOW SHWRS FOLLOWED BY HOWLING N
WINDS UP TO 50 MPH...
ALOFT: SEVERAL WEAK/SUBTLE SHORTWAVE TROFS WILL CROSS THE FCST
AREA THRU TONIGHT IN NW FLOW. THE LEAD TROF WILL BE THE POTENTIAL
WX- MAKER WHICH WILL MOVE THRU 15Z-00Z...ASSOCIATED WITH THE
PASSAGE OF THE SFC LOW.
SURFACE: AN ARCTIC COLD FRONT EXTENDED FROM HUDSON BAY THRU THE
GREAT LAKES ACROSS IA TO LOW PRES OVER SD AND THEN NW INTO CANADA.
THIS LOW WILL HEAD SE ACROSS NEB TODAY AND IN ITS WAKE THE FRONT
WILL SURGE S TODAY AND WILL BE S OF THE FCST AREA BY SUNSET.
ARCTIC HIGH PRES THEN BEGINS BUILDING IN TONIGHT FROM CANADA.
EARLY THIS MORNING: CLOUDS WILL CONT TO INCREASE FROM THE NW.
GENERALLY MILD WITH TEMPS AT OR ABOVE FRZG MOST LOCATIONS.
HAZARDS: N WINDS WILL GUST 45-50 MPH 12PM-12AM. DANGEROUS WIND
CHILLS DOWN TO -20F LATE TONIGHT...N OF I-80.
TODAY: NOT SURE HOW IT UNFOLDS. WE KNOW FOR SURE THAT THE
STEADIEST PRECIP WILL BE E OF THE FCST AREA...ON THE COLD SIDE OF
THE FRONT IN THE WAA. SPOTTY ECHOES HAVE BEEN INCREASE THRU THE
NIGHT SW OF THE LOW THRU THE BLACK HILLS INTO THE PANHANDLE.
UPSTREAM SOUNDINGS SHOW A LOT OF DRY AIR IN THE LOW-LVLS. SO FAR
HAVE ONLY SEEN ONE STATION REPORT SPRINKLES UPSTREAM.
OVERALL EXPECT A M/CLOUDY DAY OVER S-CNTRL NEB AND BECOMING
M/CLOUDY OVER N-CNTRL KS. MOST MESOSCALE MODELS SUGGEST A
NARROW/BROKEN BAND OF STRONGLY-FORCED SHWRS WILL DEVELOP ALONG THE
FRONT WHICH COULD BRIEFLY CHANGEOVER TO SNOW BEFORE ENDING...
PRIMARILY N OF HWY 6. PRECIP WILL INITIALLY STRUGGLE TO REACH THE
GROUND. THE ENVIRONMENT IS NOT FAVORABLE FOR MUCH MEASURABLE
PRECIP.
THE LOWEST CONFIDENCE PORTION OF THE FCST IS TEMPS. WE COULD BE
TOO COOL. MULTIPLE OVERNIGHT CYCLES OF THE RAP SUGGEST 50F UP TO
I-80 AND NEARING 60 OVER N-CNTRL KS. I COULD ONLY ENVISION THAT
HAPPENING WITH FULL SUN AND THAT IS NOT EXPECTED. USED CONSENSUS
OF HI-RES SHORT-TERM MODELS FOR HIGHS AND THEN NUDGED HIGHS MORE
INTO THE 50S OVER N-CNTRL KS IN COORDINATION WITH KS OFFICES.
TEMPS WILL FALL THIS AFTERNOON N OF I-80 BEHIND THE FRONT.
WINDS: BLENDED THE 18Z/00Z MAV MOS 50-50. N WINDS WILL HOWL...
GUSTING 45-50 MPH IN THE TIGHT PRES GRADIENT/CAA BEHIND THE LOW. 6
HR PRES RISES OF 12 MB ARE LIKELY.
TONIGHT: CLOUDY...WINDY AND TURNING VERY COLD. WINDS WILL BE
STRONGEST PRIOR TO MIDNIGHT. TEMPS PLUMMET INTO THE SINGLE DIGITS
OVER N-CNTRL NEB AND LINGERING WINDS WILL PUSH WIND CHILLS AS LOW
AS -20F.
CAA WILL RESULT IN SOME MODEST INSTABILITY IN THE LINGERING
STRATUS WHICH WILL COOL INTO THE IDEAL SNOW GROWTH LAYER. SO KEPT
THE MENTION OF FLURRIES FROM THE PREVIOUS FCST.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 354 AM CST WED FEB 25 2015
THIS SECTION WILL UPDATE SOON.
&&
.AVIATION...(FOR THE 06Z KGRI/KEAR TAFS THROUGH 06Z WED NIGHT)
ISSUED AT 1159 PM CST TUE FEB 24 2015
REST OF TONIGHT: MULTI-LAYERED VFR MID-LVL CIGS WILL OVERTAKE THE
TERMINALS FROM THE N...REMAINING AT OR ABOVE 10K FT. SSW WINDS
JUST UNDER 10 KTS. THERE MAY BE SOME MARGINAL LLWS BASED ON WINDS
FROM OUR RADAR AT 400 FT...BUT THESE WINDS MAY BE OVERDONE.
CONFIDENCE: HIGH
TUE: VFR CIGS LOWER TO AROUND 3500 FT. COLD FRONT PASSES THE
TERMINALS AROUND 18Z WITH A BRIEF BURST OF POSSIBLY IFR SNOW.
THERE IS UNCERTAINTY IN THE INTENSITY OF THE SNOW. IF THE WORST
CASE OCCURS...ANY ACCUM WOULD BE LESS THAN 1 INCH. MVFR CIGS MOVE
IN AFTER FRONTAL PASSAGE AND N WIND WILL GUST TO 35 KTS...WITH A
ONE-TIME PKWND OF 40 KTS POSSIBLE. CONFIDENCE: MEDIUM
TUE EVE: MVFR CIGS REMAIN. N WINDS WILL BE GRADUALLY DECREASING.
CONFIDENCE: MEDIUM
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...HALBLAUB
LONG TERM...HEINLEIN
AVIATION...HALBLAUB
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
257 AM CST WED FEB 25 2015
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 216 AM CST WED FEB 25 2015
INITIAL CONCERN WILL BE TYPE AND EXTENT OF PRECIP AS SURFACE LOW
TRACKS ACROSS THE AREA TODAY. THEN COLD AND WINDY CONDITIONS WITH
SUBZERO WIND CHILLS APPROACHING CRITERIA THURSDAY MORNING. JUST
PLAIN COLD FRIDAY MORNING.
SURFACE LOW WAS LOCATED OVER SOUTH CENTRAL SOUTH DAKOATA AT 08Z
WITH PRIMARY BAND OF PRECIP FROM EASTERN SOUTH DAKOTA INTO
SOUTHWEST MINNESOTA AND NORTHWEST IOWA. BOTH THE HRRR AND RAP
SLOWER IN BRINGING THE PRECIP SHIELD SOUTH TODAY WITH PRIMARY BAND
STRETCHING ACROSS NORTHERN IOWA THROUGH THE MORNING. HAVE ADJUSTED
TIMING OF THE WINTER WEATHER ADVISORY TO ACCOUNT FOR THIS FEATURE
AND ALSO REMOVED THE TWO SOUTHWEST IOWA COUNTIES AS TEMPERATURES
ARE EXPECTED TO REMAIN ON THE WARM SIDE THERE FOR MOST OF THE DAY
WITH BETTER QPF EAST OF THE AREA.
HAVE TRENDED TEMPERATURES WARMER ACROSS THE SOUTH HALF OF THE AREA
AND BACKED OFF FURTHER ON PRECIP AND SNOW ACROSS THE SOUTH.
TEMPERATURES WILL BE TRICKY TODAY AND DEPEND ON TIMING OF THE COLD
AIR BEHIND THE FRONT THIS AFTERNOON AS THE LOW TRACKS ACROSS EAST
CENTRAL NEBRASKA TOWARD NORTHWEST MISSOURI. A PERIOD OF MIXED
PRECIP...WHICH COULD INCLUDE FREEZING RAIN...IS POSSIBLE FOR A
TIME THIS MORNING IN PARTS OF NORTHEAST NEBRASKA INTO WEST CENTRAL
IOWA BEFORE THE COLD AIR MOVES IN BEHIND THE FRONT. AMOUNTS SHOULD
BE LIGHT WITH LIMITED AREAL COVERAGE.
THE ARCTIC AIR SPREADS RAPIDLY SOUTH TONIGHT ALONG WITH GUSTY
NORTHWEST WINDS. SUBZERO WIND CHILLS ARE LIKELY ACROSS THE AREA BY
THURSDAY MORNING WITH NORTHERN COUNTIES APPROACHING ADVISORY
CRITERIA. WILL COVER THE COLD IN HWO FOR NOW BUT ADVISORY LOOKS
LIKELY IN LATER FORECASTS. WINDY AND COLD CONDITIONS WILL EXTEND
THROUGH THE DAY ON THURSDAY WITH WINDS DIMINISHING THURSDAY
EVENING. TEMPERATURES ARE EXPECTED TO PLUNGE BELOW ZERO THURSDAY
NIGHT AS HIGH SETTLES OVER THE AREA AND WINDS BECOME LIGHT. SLOW
WARMING???? ON FRIDAY AS HIGH MOVES EAST.
.LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY)
ISSUED AT 216 AM CST WED FEB 25 2015
LITTLE CHANGE TO GENERAL TRENDS. WEEKEND SYSTEM STILL KEEPS MAIN
PRECIP AXIS TO THE SOUTH WITH LIGHTER AMOUNTS FOR THE SOUTH HALF
OF THE CWA. MORE SIGNIFICANT SNOW POSSIBLE MONDAY INTO TUESDAY AS
MAIN WAVE COMES INTO THE PLAINS REGION.
&&
.AVIATION...(06Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 1120 PM CST TUE FEB 24 2015
VFR CONDITIONS ARE LIKELY TO CONTINUE OVERNIGHT. CONDITIONS WILL
DETERIORATE WEDNESDAY AND MIXED PCPN SHOULD DEVELOP. COLD AIR
MOVING IN WILL CHANGE THE PCPN TO SNOW...AND EXPECT THAT IFR
CONDITIONS WILL OCCUR WITH THE SNOW. WINDS WILL SHIFT FROM
SOUTHEAST TO THE NORTHEAST...THEN NORTH WITH GUSTS TO 39 KNOTS OR
MORE AFTER THE WIND SHIFTS TO NORTH. MVFR CEILINGS ARE LIKELY TO
CONTINUE WITH STRONG WINDS INTO WEDNESDAY EVENING.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...WINTER WEATHER ADVISORY FROM 6 AM THIS MORNING TO 6 PM CST THIS
EVENING FOR NEZ015-034.
IA...WINTER WEATHER ADVISORY FROM 6 AM THIS MORNING TO 8 PM CST THIS
EVENING FOR IAZ055-056.
WINTER WEATHER ADVISORY FROM 6 AM THIS MORNING TO 6 PM CST THIS
EVENING FOR IAZ043.
WINTER WEATHER ADVISORY FROM 2 PM THIS AFTERNOON TO 8 PM CST
THIS EVENING FOR IAZ069.
&&
$$
SHORT TERM...FOBERT
LONG TERM...FOBERT
AVIATION...MILLER
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
731 PM MST THU FEB 26 2015
.UPDATE...
NAM12 AND HRRR SHOW LARGER SNOW AMOUNTS OVER SOCCORO AND LINCOLN
COUNTY THAN EARLIER ANTICIPATED...AS UPPER JET SAGS FARTHER SOUTH
TONIGHT. LIGHT SNOW AT KONM PRESENTLY...SO DECIDED TO GO AHEAD
WTIH SOME EXPANDED WINTER WEATHER AVISORIES. UPDATED ZFP AND WSW
ALREADY OUT.
&&
.PREV DISCUSSION...513 PM MST THU FEB 26 2015...
.AVIATION...
00Z TAF CYCLE
EXPECT WIDESPREAD IFR TO LIFR CONDITIONS FROM CENTRAL MT CHAIN
EAST WITH MT OBSCURATIONS THROUGH MOST IF NOT ALL OF THIS 24 HR
FCST PERIOD. ALSO PATCHES OF -SN TO SN. LVS/TCC WILL BE IMPACTED
MOST WITH ROW ALSO BEING IMPACTED TO SOME DEGREE. FARTHER WEST
AREAS OF MVFR AND MORE LOCALIZED IFR CIGS CAN BE EXPECTED AT LEAST
INTO ROUGHLY MID MORN FRI. GAP WINDS INTO RIO GRANDE VALLEY ALSO
TO CONTINUE THROUGH EARLY MORN FRI THEN DIMINISH TO SOME DEGREE.
AT AND NEAR ABQ GUSTS MAY APPROACH 35 KT AT TIMES BETWEEN 02Z OR
03Z UNTIL ABOUT 10Z. AWW MAY BE ISSUED VERY EARLY THIS EVE FOR ABQ
DUE TO THE GUSTY WINDS AND OR SNOW ACCUMULATION POTENTIAL...BUT
TOUGH CALL AS CONFIDENCE FOR GUSTS THAT HIGH OR SNOW ACCUM OF AN
INCH OR MORE IS NOT THAT HIGH. IFR/MVFR CIGS AND OCCASIONALLY VSBY
DUE TO SN IS EXPECTED AT ABQ/SAF/AEG MAINLY BETWEEN 02Z AND 09Z
AND FOR GUP AND FMN TO A SLIGHTLY LESSER DEGREE.
43
&&
.PREV DISCUSSION...333 PM MST THU FEB 26 2015...
.SYNOPSIS...
AN UNSETTLED WEATHER PATTERN WILL CONTINUE OVER NORTHERN AND
CENTRAL NEW MEXICO THROUGH THE NEXT SEVERAL DAYS AS NUMEROUS
DISTURBANCES ALOFT BRING PRECIPITATION TO THE STATE. TEMPERATURES
ARE CURRENTLY WELL BELOW AVERAGE...ESPECIALLY IN THE EASTERN
PLAINS OF THE STATE WHERE READINGS ARE SOME 30 DEGREES BELOW
NORMAL FOR LATE FEBRUARY. WITH COLDER AIR IN PLACE...SNOW IS
EXPECTED TO BREAK OUT OVER MUCH OF CENTRAL TO EASTERN NEW MEXICO
TONIGHT INTO FRIDAY AS AN UPPER LEVEL DISTURBANCE APPROACHES.
SEVERAL INCHES OF ADDITIONAL ACCUMULATION ARE EXPECTED BY
TOMORROW...ESPECIALLY IN THE MOUNTAINS AND HIGHLANDS OF NORTHERN
AND CENTRAL NEW MEXICO. AS THE WEEKEND UNFOLDS...ANOTHER POTENT
DISTURBANCE WILL DIVE INTO CALIFORNIA BEFORE SLOWLY SPREADING OVER
NEW MEXICO. A PROLONGED PERIOD OF HIGH ELEVATION SNOW IS EXPECTED
SATURDAY...SUNDAY...AND INTO MONDAY AND TUESDAY. THE HIGHEST SNOW
TOTALS WILL BE FOUND IN THE SAN JUAN OR TUSAS MOUNTAINS NEAR THE
COLORADO BORDER WHERE TWO TO FOUR FEET OF SNOW COULD ACCUMULATE
ABOVE TEN THOUSAND FEET. RAIN WILL FALL IN LOWER ELEVATIONS DURING
THIS WEEKEND TO EARLY NEXT WEEK PERIOD.
&&
.DISCUSSION...
IT HAS BEEN AN EXTREMELY BUSY SHIFT TODAY WITH A FOCUS ON WINTER
HIGHLIGHTS IN NOT ONLY THE NEAR TERM...BUT ALSO FOR THE NEXT
IMPENDING UPPER LOW THAT WILL BEGIN IMPACTING NM THIS WEEKEND.
SOMEWHAT OF A LULL OR RESPITE HAS BEEN OBSERVED THIS AFTERNOON
WITH REGARDS TO SNOW...BUT IT HAS NOT FULLY ENDED IN SOME OF THE
NORTHERN MOUNTAIN LOCALES. THE NEXT UPSTREAM DISTURBANCE IS
LOOKING HEALTHY ON WATER VAPOR SATELLITE IMAGERY...CURRENTLY JUST
WEST OF THE FOUR CORNERS AREA...PERHAPS A BIT FARTHER SOUTH THAN
MODELS HAVE BEEN INDICATING. THIS WILL SPREAD SUFFICIENT DYNAMICS
ALOFT TO SATURATE THE MID LEVELS OF THE ATMOSPHERE WHICH WILL THEN
SEED LOWER LEVELS AND PRODUCE SIGNIFICANT SNOW...ESPECIALLY WHERE
EAST/SOUTHEAST UPSLOPE FLOW WILL BE RUNNING UP ON THE RESPECTIVE
SLOPES OF HIGHER TERRAIN. SANGRES AND CENTRAL MOUNTAINS/HIGHLANDS
APPEAR TO BENEFIT THE MOST FROM THE UPSLOPE WHILE SATURATED MID
LEVEL CLOUD DECKS WILL SEED LOWER LAYERS...INDUCING SNOW GROWTH.
IN ADDITION THE DYNAMICS SHOULD BE ENOUGH TO PRODUCE SIGNIFICANT
SNOWFALL OVER THE HIGHER PEAKS OF THE REMAINING NORTHERN
MOUNTAINS. THE EASTERLY FLOW HAS BEEN ACCELERATING THROUGH
GAPS/CANYONS WITHIN THE CENTRAL MOUNTAIN CHAIN...AND AN EARLY
EVENING SURGE SHOULD ALLOW SPEEDS TO JUMP UP SEVERAL MPH AT KABQ
AND KSAF. THIS SHOULD SHADOW MUCH OF THE ALBUQUERQUE METRO AREA
WITH REGARD TO SNOW...SO HIGHLIGHTS WERE HEDGED ON LOWER SIDE WITH
JUST AN ADVISORY.
AS THIS EVENING`S DISTURBANCE TRACKS INTO TX ON FRIDAY...SNOW WILL
BEGIN TO TAPER OFF TOWARD MID DAY. SOME UPSLOPE WILL CONTINUE
THOUGH...KEEPING THOSE FAVORED AREAS PRECIPITATING AT LIGHT RATES.
SOME OF THE HIGHLIGHTS WILL NEED TO BE CONTINUOUSLY MONITORED TO
DECIDE ON EARLIER EXPIRATION FRIDAY. TEMPERATURES WILL BE EVEN
COLDER IN MOST ZONES ON FRIDAY AS THE SYNOPTIC COLD POOL CONTINUES
SEEPING WESTWARD. THIS WILL PUT MOST ZONES AT 10 TO 40 DEGREES
BELOW NORMAL FRIDAY AFTERNOON. INTERESTINGLY MODELS BREAK OUT NEW
BATCHES OF PRECIPITATION IN THE NORTHWESTERN QUADRANT OF THE STATE
FRIDAY AFTERNOON. WITHOUT THE PRESENCE OF ANY BLATANT PERTURBATION
IMMEDIATELY UPSTREAM...IT APPEARS THE TRIGGER IS SOME DIVERGENCE
ALOFT...ASSOCIATED WITH JET DYNAMICS FAR AHEAD OF THE NEXT TROUGH
DIVING INTO THE GREAT BASIN. HAVE INCREASED POPS SOME TO REFLECT
HIGHER PROBABILITIES IN THE NORTHWESTERN ZONES...BUT MAY NOT HAVE
RAISED ENOUGH.
CONFIDENCE IS HIGHER IN THE ELEVATED PROBABILITIES OVER
NORTHWESTERN TO WEST CENTRAL NM FRIDAY NIGHT AND SATURDAY AS THE
AFOREMENTIONED TROUGH DIVES SOUTHWARD OVER CALIFORNIA AND DEEPENS
INTO A LOW...SHEDDING ENERGY INTO AZ/NM. THIS WILL BRING A
STIFFENING SOUTHWESTERLY FLOW OVER NM THAT WOULD HAVE GOOD
OROGRAPHICS ASSOCIATED WITH IT WHILE ALSO ACTING AS A WARM
ADVECTION CATALYST. HAVE OPTED TO ISSUE WINTER STORM WATCH FOR THE
SAN JUAN/TUSAS AND JEMEZ ZONES STARTING FRIDAY NIGHT AND RUNNING
INTO SUNDAY. QPF AMOUNTS ARE VERY IMPRESSIVE WITH THIS FEATURE
FRIDAY NIGHT THROUGH SUNDAY. CHALLENGES WILL ARISE FROM THE WARM
ADVECTION...INDUCING RISING SNOW LEVELS AND COMPLICATING THE SNOW
RATIOS. AT THIS POINT IT STILL APPEARS 2 TO 4 FEET OF NEW SNOW
WOULD BE REASONABLE IN THIS SCENARIO NEAR THE CO-NM BORDER ABOVE
10KFT. SNOW LEVELS WOULD LIKELY RISE TO NEAR 8000 TO 8500 FEET
SUNDAY...AND WHILE THIS MIGHT SUGGEST A LIMITING OF ACCUMULATIONS
AND IMPACTS...THE HYDROLOGY IMPACTS WILL HAVE TO BE STRONGLY
CONSIDERED. IF HEALTHY RAINFALL OCCURS OVER SOME OF THE SNOW
PACK...IN THE 7000 TO 9000 FT RANGE...SOME SUBSTANTIAL MELT AND
RUNOFF COULD OCCUR. WILL MONITOR THIS SCENARIO CLOSELY THE NEXT
COUPLE OF DAYS.
AS THE CA LOW FINALLY DRAGS NORTHEASTWARD OVER NM MONDAY AND
MONDAY NIGHT...ANOTHER PERTURBATION WILL DROP DOWN ON ITS HEELS
TUESDAY...FOLLOWED BY ANOTHER ON WEDNESDAY. THE WEDNESDAY FEATURE
COULD ALLOW A VERY COLD DOME TO SPILL SOUTHWARD INTO NM...BUT IT
WOULD APPEAR TO BE THE CABOOSE ON THE RECENT STORM TRAIN.
52
&&
.FIRE WEATHER...
NO FIRE WEATHER CONCERNS NEXT SEVERAL DAYS. THE ACTIVE WINTER
WEATHER PATTERN WILL CONTINUE THROUGH MIDDLE OF NEXT AS A SERIES
OF UPPER LEVEL DISTURBANCES CROSS OVER THE STATE. TEMPS AREAWIDE
WILL REMAIN BELOW NORMAL THROUGH WEDNESDAY WITH UNUSUALLY HIGH
HUMIDITY.
GUSTY GAP WINDS WILL CONTINUE ALONG THE CENTRAL MOUNTAINS FOR THE
NEXT 24-48 HOURS. OTHERWISE...ANOTHER ROUND OF WETTING SNOW WILL
DEVELOP AND FAVOR CENTRAL/EASTERN AREAS TONIGHT INTO FRIDAY
MORNING. SNOW SHOWERS SHOULD CONTINUE ACROSS WESTERN/CENTRAL AREAS
FRIDAY AFTERNOON.
WETTING PRECIPITATION WILL THEN BE CONFINED TO OVER NORTHERN AND
WESTERN AREAS THIS WEEKEND. SNOW LEVELS WILL RISE DURING THIS PERIOD
AS THE ATMOSPHERE WARMS. MODELS HAVE BEEN TRENDING TOWARDS MORE OF
AN UPPER LEVEL DRY SLOT IMPACT SOUTH CENTRAL/SOUTHEAST AREAS DURING
THIS SAME PERIOD. TEMPERATURES WILL MODIFY SOME BUT WILL REMAIN
BELOW NORMAL. BREEZY CONDITIONS ARE EXPECTED ACROSS WESTERN/CENTRAL
AREAS ESPECIALLY FAVORING THE HIGH TERRAIN. WINDY CONDITIONS ARE
VERY POSSIBLE ACROSS THE HIGH TERRAIN AS THE FLOW ALOFT INCREASES.
MORE UPPER LEVEL DISTURBANCES FROM THE WEST WILL FOLLOW MONDAY THRU
WEDNESDAY BRINGING MORE RAIN/SNOW SHOWERS TO WESTERN AND CENTRAL
AREAS. EASTERN AREAS SHOULD GET INTO THE ACTION BY MIDWEEK. TEMPS
WILL BE A BIT WARMER IN THE EAST...COOLER IN THE WEST ON MONDAY AND
TUESDAY..THEN COOLING ALL OVER WEDNESDAY.
VENTILATION IS EXPECTED TO LOWER ON FRIDAY DUE TO LOWER MIXING
HEIGHTS AND IMPACTS FROM THE BACK DOOR COLD PUSH. VENTILATION WILL
IMPROVE AS THE WEEKEND PROGRESSES...ESPECIALLY ON SUNDAY. GOOD TO
EXCELLENT VENT RATES ARE EXPECTED EARLY NEXT WEEK AS THE ATMOSPHERE
REMAINS UNSETTLED AND HIGHER TRANSPORT WINDS EXIST.
50
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL NOON MST FRIDAY FOR THE FOLLOWING
ZONES...NMZ504-507-508-520-524>526-530-533>540.
WINTER STORM WARNING UNTIL NOON MST FRIDAY FOR THE FOLLOWING
ZONES...NMZ512>516-527>529-531-532.
WINTER WEATHER ADVISORY UNTIL 5 PM MST FRIDAY FOR THE FOLLOWING
ZONES...NMZ517-519.
WINTER STORM WARNING UNTIL 5 PM MST FRIDAY FOR THE FOLLOWING
ZONES...NMZ510-511-518-521>523.
WINTER STORM WATCH FROM LATE FRIDAY NIGHT THROUGH SUNDAY AFTERNOON
FOR THE FOLLOWING ZONES...NMZ510-511.
&&
$$
AREA FORECAST DISCUSSION
NWS RALEIGH NC
926 PM EST THU FEB 26 2015
.SYNOPSIS... LOW PRESSURE WILL MOVE AWAY FROM THE NORTH CAROLINA
COAST THIS EVENING. HIGH PRESSURE OVER THE CENTRAL PLAINS WILL BUILD
INTO THE MID ATLANTIC ON FRIDAY INTO SATURDAY.
&&
.NEAR TERM /THROUGH FRIDAY/...
AS OF 320 PM THURSDAY...
...WINTER WEATHER ADVISORY FOR BLACK ICE IN EFFECT FROM 9PM TONIGHT
THROUGH 10 AM FRIDAY...
ANOTHER COMPLICATED FORECAST FOR TONIGHT AND INTO FRIDAY WITH LOTS
OF CONSIDERATIONS INCLUDING LOW TEMPERATURES FCST ISSUES...BLACK
ICE...FOG OR FREEZING FOG AND PERHAPS SOME SPOTTY LIGHT FREEZING
RAIN OR SNOW ACROSS THE NORTHWEST PIEDMONT.
WIDESPREAD LOW OVERCAST CONTINUES ACROSS CENTRAL NC THIS AFTERNOON
WITH JUST A FEW BREAKS ACROSS THE WESTERN PIEDMONT. WHILE SOME
ADDITIONAL BREAKS MAY DEVELOP THIS EVENING...AN APPROACHING SHEARED
SHORT WAVE TROUGH ALOFT AND SHALLOW LOW LEVEL ASCENT SHOULD WORK TO
MAINTAIN A FAIR DEGREE OF CLOUDINESS OVERNIGHT. MODEL BUFR
SOUNDINGS...ESPECIALLY THE NAM/HRRR AND RAP AGGRESSIVELY COOL THE
SURFACE AND GENERATE A NOTABLE AREA OF SHALLOW STRATUS AND/OR DENSE
FOG. NOT VERY CONFIDENT ON THE HOW THIS WILL EVOLVE AND THE DEGREE
OF FOG DEVELOPMENT GIVEN MIXED SIGNALS IN THE PATTERN. CONDITIONS AT
THE GROUND LEVEL ARE VERY MOIST WITH EITHER A FRESH SNOW COVER OF
WET SNOW OR MELT WATER OR JUST DAMP CONDITIONS FROM HEAVY RAIN LAST
NIGHT. SKIES ARE NOT EXPECTED TO CLEAR MUCH OVERNIGHT SO RADIATIONAL
CONDITIONS ARE NOT IDEAL. IN ADDITION WEAK WEAK COOL ADVECTION OVER
A SNOW PACK GENERALLY ISN`T FAVORABLE FOR FOG DEVELOPMENT. STILL SOME
FOG IS EXPECTED AND WILL BE ADDED TO THE FORECAST.
TO FURTHER COMPLICATE THINGS...THE NAM AND GFS SUGGEST SOME SPOTTY
LIGHT PRECIPITATION WILL DEVELOP OVERNIGHT IN THE TRIAD AS A WEAK
SURFACE TROUGH DROPS SOUTHEAST AND A SHEARING SHORT WAVE CROSSES THE
REGION. HIGH RES CONVECTION ALLOWING MODELS ALSO GENERATE SOME
PRECIPITATION. WHILE CONFIDENCE IS LOW...FEEL IT IS PRUDENT TO ADD A
SLIGHT CHANCE OF SOME SPOTTY FREEZING DRIZZLE. THE SATURATION IS
SHALLOW BUT MAY BE SUFFICIENTLY DEEP TO APPROACH THE ICE NUCLEATION
REGION AND WARRANT THE INCLUSION OF SOME SPOTTY LIGHT SNOW. SO WEVE
ADDED A SLIGHT CHANCE OF SOME FREEZING RAIN AND LIGHT SNOW IN THE
TRIAD TONIGHT.
LOW TEMPERATURES TONIGHT ARE ALSO PROBLEMATIC GIVEN THE NEW SNOW
COVER WHICH WOULD GENERALLY PROMOTE COOLING AND LOWER TEMPERATURES.
HIGHER RESOLUTION GUIDANCE INCLUDING THE RAP AND HRRR JUMP ALL OVER
THE LOCALIZED COOLING AND SUGGEST LOWS IN THE 10-15 RANGE ACROSS
MUCH OF THE FRESH SNOW COVER AREA. GIVEN THE AMOUNT OF CLOUD COVER
AND NON IDEAL RADIATIONAL CONDITIONS...THIS SEEMS OVERDONE. ALSO THE
RIPENESS OF THE SNOW WOULD SUGGEST A LOWER CHILLING EFFECT OF THE
SNOW COMPARED TO A NEW VIRGIN SNOW COVER. HAVE GONE WITH A FORECAST
OF LOWS RANGING FROM THE 21 TO 27 DEGREES FROM NORTHEAST TO
SOUTHWEST.
WITH THESE TEMPERATURES IN MIND...EXPECT ANY LINGERING MOISTURE ON
AREA ROADS TO REFREEZE OVERNIGHT. TEMPERATURES GENERALLY WONT FALL
BELOW FREEZING UNTIL AFTER 9PM AND EXPECT REFREEZING TO BE MOST
PROBLEMATIC AFTER MIDNIGHT.
FRIDAY SHOULD FEATURE A GOOD DEAL OF CLOUDINESS TO START.
TEMPERATURES WILL SLOWLY CLIMB TO AROUND FREEZING BY 10AM ALTHOUGH
THIS COULD BE DELAYED IF CLOUD COVER HOLDS LONGER OR LOWS TONIGHT
BOTTOM OUT EVEN FURTHER THAN FORECAST. EXPECT SOME BREAKS IN THE
CLOUDS ON FRIDAY AFTERNOON WITH HIGHS CLIMBING INTO THE UPPER 30S TO
LOWER 40S. -BLAES
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY/...
AS OF 320 PM THURSDAY...
1044 HPA HIGH BUILDING ACROSS THE GREAT LAKES BEGINS RIDGING SOUTH
INTO THE AREA. IN ADDITION...A WEAK SHORT WAVE WILL BE RACING ACROSS
THE NORTHERN TIER OF THE STATE IN FAST WEST SOUTHWEST FLOW. THE
LATEST GFS AND NMM SHOW SPOTTY SHOWERS IN THE FOOTHILLS AND A FLURRY
INTO THE FAR NORTHWEST LOOKS POSSIBLE...BUT MOISTURE WILL VERY
LIMITED (PW ~0.25 IN) AND WILL MAINTAIN A DRY...BUT MOSTLY CLOUDY
FORECAST OVERNIGHT. COOL AIRMASS IN PLACE AND REINFORCED CAA
OVERNIGHT WILL PRODUCE MINS IN THE UPPER TEENS IN THE NORTHEAST...
WITH MOSTLY LOWER 20S ACROSS THE SOUTH.
CONSIDERABLE CLOUDINESS ALONG WITH DAMMING SETTLED IN PLACE SATURDAY
WILL PRODUCE ANOTHER WELL-BELOW NORMAL DAY. HIGHS IN THE 30S...FROM
LOW 30S NORTHEAST UNDER THE RIDGE AXIS...TO NEAR 40 IN THE FAR
SOUTHWEST. MINS SATURDAY NIGHT WILL BE SIMILAR TO FRIDAY
NIGHT...PERHAPS A DEGREE OR TWO LOWER IF SKIES ARE CLEAR ENOUGH TO
PROMOTE BETTER RADIATION...WITH TEENS IN THE NORTHEAST TO MOSTLY
LOWER 20S ELSEWHERE.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 320 PM THURSDAY...
THERE IS A LOT OF UNCERTAINTY AS TO PRECIPITATION TIMING AS SPLIT
FLOW PATTERN CONTINUES INTO NEXT WEEK. INITIAL COLD AIR DAMMING
SUNDAY WILL BE NUDGED OFFSHORE BY A NORTHERN STREAM SHORT WAVE AND
ASSOCIATED COLD FRONT WHICH WILL BE MOVING ACROSS THE AREA SUNDAY
NIGHT...WITH PRECIP AHEAD OF THE FRONT EARLY SUNDAY NIGHT SPREADING
INTO THE EAST AFTER MIDNIGHT. HIGHS SUNDAY WILL BE MOSTLY IN THE LOW
TO MID 40S. MINS WILL BE MODERATING A BIT SUNDAY NIGHT WITH HEAVIER
CLOUDINESS AND SCOURING OF THE ARCTIC AIRMASS KEEPING MINS IN THE
30S.
THE AIRMASS SETTLING IN BEHIND THE FRONT WILL BE CONSIDERABLY
MILDER...BUT THE OVERALL PATTERN CONTINUES TO FAVOR YET ANOTHER
TRANSITION TO A DAMMING SCENARIO BY TUESDAY. A BACKDOOR FRONT SAGS
SOUTH ON MONDAY...WITH GOOD CHANCES OF RAIN WHICH WOULD DAMPEN/DELAY
THE POTENTIAL WARMUP INTO MID WEEK. WILL MAINTAIN A WARMUP INTO THE
50S PRE-FROPA ON MONDAY...ALONG WITH RAIN WHICH WOULD PRODUCE AN IN-
SITU COOLOFF ON TUESDAY...WITH HIGHS IN THE MID 40S WEST TO MID 50S
EAST. PROBABILITY OF RAIN WILL REMAIN AT LEAST IN THE CHANCE
CATEGORY ON WEDNESDAY INTO THURSDAY AHEAD OF A STRONG FRONTAL SYSTEM
APPROACHING FROM THE WEST. THIS SLOW MOVING SYSTEMS TIMING IS NOT
VERY CERTAIN AT THIS TIME...BUT IT LOOKS LIKE IT WOULD BE ON
WEDNESDAY NIGHT...WITH WARM AIR ADVECTION AHEAD OF THE SYSTEM
WARMING US INTO THE 60S ON WEDNESDAY AND EVEN THURSDAY AS COLD AIR
ADVECTION IS DELAYED TIL LATE DAY.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
AS OF 900 PM THURSDAY...
24-HR TAF PERIOD: BELOW NORMAL CONFIDENCE THROUGH 12Z FRI. AREAS OF
FOG/FREEZING FOG AND LOW STRATUS ARE EXPECTED TO DEVELOP OVERNIGHT.
LIFR/VLIFR CONDITIONS ARE POSSIBLE. CONDITIONS WILL GRADUALLY
IMPROVE AFTER SUNRISE WITH LINGERING FOG AND STRATUS GIVING WAY TO
SCT/BKN CEILINGS WITH BASES 3-4 KFT BY FRIDAY AFTERNOON.
LOOKING AHEAD: GENERALLY FAIR WEATHER CONDITIONS ARE EXPECTED FRIDAY
NIGHT INTO SATURDAY NIGHT. AVIATION CONDITIONS ARE LIKELY TO
DETERIORATE ON SUNDAY WITH ADVERSE AVIATION CONDITIONS LIKELY
PERSISTING INTO MID WEEK. -VINCENT/BLAES
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 9 PM THIS EVENING TO 10 AM EST
FRIDAY FOR NCZ007>011-021>028-038>043-073>078-083>086-088-089.
&&
$$
SYNOPSIS...BLAES
NEAR TERM...BLAES
SHORT TERM...MLM
LONG TERM...MLM
AVIATION...VINCENT/BLAES
AREA FORECAST DISCUSSION
NWS RALEIGH NC
320 PM EST WED FEB 25 2015
.SYNOPSIS...AN AREA OF LOW PRESSURE MOVES QUICKLY FROM THE NORTHERN
GULF OF MEXICO...TO OFF THE CAROLINA COAST OVERNIGHT THROUGH EARLY
THURSDAY. COLD CANADIAN HIGH PRESSURE THEN BUILDS INTO THE REGION
FRIDAY AND INTO THE WEEKEND.
&&
.NEAR TERM /TODAY THROUGH THURSDAY/...
AS OF 150 PM WEDNESDAY...
...WINTER STORM WARNING HAS BEEN ISSUED FOR TONIGHT AND THURSDAY FOR
ALL THE PIEDMONT...NORTHERN/CENTRAL COASTAL PLAIN AND SANDHILLS...
...WINTER WEATHER ADVISORY HAS BEEN ISSUED FOR TONIGHT AND THURSDAY
FOR THE SOUTHERN COASTAL PLAIN...
MORNING UPPER AIR ANALYSIS SHOWS THE SHEARING SHORT WAVE TROUGH OVER
TEXAS THIS MORNING WITH SHORT WAVE RIDGING OUT AHEAD OF IT ACROSS
THE SOUTHEAST. HIGH CLOUDS HAVE BEEN ADVANCING NORTHEAST AHEAD OF
THE SYSTEM AND MOST OF CENTRAL NC IS ALREADY UNDER AT LEAST A THIN
VEIL OF CIRRUS. REGIONAL RADAR IMAGERY SHOWS PRECIPITATION EXPANDING
ACROSS THE DEEP SOUTH WITH MEASURABLE PRECIP NOW REPORTED ACROSS
CENTRAL ALABAMA. NO PRECIPITATION IS EXPECTED IN CENTRAL NC DURING
THE TODAY PERIOD BUT TODAYS WEATHER COULD STILL PLAY A ROLE IN THE
IMPACT OF TONIGHTS WINTER STORM. THE TEMPERATURES FORECAST FOR TODAY
IS PROBLEMATIC AS YESTERDAYS SNOWFALL WILL DAMPEN THE TEMPERATURE
RECOVERY THIS AFTERNOON AND ENERGY IS DIVERTED INTO MELTING AND
EVAPORATING SNOW AND MELT WATER. EVEN SO...SOME GUIDANCE INCLUDING
THE HRRR SUGGEST HIGHS IN THE MID 40S TO AROUND 50. NOT READY TO
JUMP THAT HIGH BUT CURRENT TEMP AT OUR OFFICE IS 37 AT 1045 AND HAVE
MADE A SLIGHT UPWARD ADJUSTMENT IN TEMPERATURES FOR TODAY. THIS
UPWARD TREND IN BOUNDARY LAYER TEMPERATURES WOULD DELAY THE
CHANGEOVER FROM RAIN OR MIXED RAIN AND SNOW THIS EVENING TO SNOW AND
POTENTIALLY LIMIT ACCUMULATIONS A BIT...PRIMARILY ACROSS THE FAR
SOUTHERN TIER IN THE SANDHILLS AND SOUTHERN COASTAL PLAIN. -BLAES
THERE HAS BEEN A CONTINUED SLIGHT NORTHWARD SHIFT IN GUIDANCE SINCE
YESTERDAY...WHICH EQUATES TO A WETTER AND MARGINALLY WARMER SOLUTION
FOR CENTRAL NC...THOUGH THE OVERALL PATTERN REMAINS UNCHANGED WITH
THE DEAMPLIFICATION/ENE SHEARING OF A SHORTWAVE TROUGH FROM NEAR THE
RIO GRANDE THIS MORNING TO THE MIDDLE ATLANTIC COAST BY THU MORNING.
THE ASSOCIATED FORCING FOR ASCENT ATOP A PAIR OF CLOSELY-SPACED AND
STRONG FRONTAL ZONES DRAPED ACROSS THE NORTHERN GOM TO A SFC LOW
ABOUT MIDWAY BETWEEN CAPE HATTERAS AND BERMUDA...WILL RESULT IN THE
CONTINUED DEEPENING OF A SFC LOW OVER THE NW GOM THIS MORNING.
GUIDANCE IS THEN FAIRLY TIGHTLY CLUSTERED WITH THE TRACK OF A MILLER
"A" SFC LOW ACROSS THE NORTHERN FL PENINSULA THIS EVENING AND
ROUGHLY ALONG THE GULF STREAM TO JUST EAST OF CAPE HATTERAS BY 12Z
THU.
AS HAS BEEN NOTED IN PREVIOUS DISCUSSIONS...THE LACK OF A PARENT
COLD HIGH IS ADMITTEDLY SOMEWHAT CONCERNING. AN ARCTIC SFC HIGH AT
1045 MB WILL BE CENTERED OVER SOUTHERN ALBERTA/SASKATCHEWAN AND WILL
CONSEQUENTLY HAVE LITTLE INFLUENCE AT OUR LATITUDE DURING THE HEIGHT
OF THE STORM TONIGHT. HOWEVER...A VERY FAVORABLE MILLER "A" CYCLONE
TRACK ALONG AND JUST OFFSHORE THE SE COAST...IN CONJUNCTION WITH A
PRECEDING ARCTIC HIGH THAT APPEARS TO BE JUST COLD ENOUGH DESPITE
BEING IN A DRAMATICALLY WEAKENED STATE FROM A COUPLE OF DAYS
AGO...BUT IS STILL CHARACTERIZED BY SFC TEMPERATURES AND DEWPOINTS
MOSTLY IN THE TEENS TO 20S OVER NC THIS MORNING...WILL SUPPORT A
SIGNIFICANT WINTER STORM **WITH A NARROW P-TYPE (SNOW/RAIN)
TRANSITION ZONE AND DEEP NEAR FREEZING ISOTHERMAL PROFILES
CHARACTERISTIC OF MILLER "A` SFC PATTERNS.** PRECIPITATION
RATES...OCCASIONALLY MODERATE TO HEAVY...WILL ONLY SERVE TO ENHANCE
THE DEEP NEAR FREEZING ISOTHERMAL PROFILES RIGHT ALONG THE SNOW/COLD
RAIN INTERFACE...OWING TO MELTING. A LITTLE MIX OF SLEET AND
FREEZING RAIN ARE HARD TO AVOID IN CENTRAL NC WINTER STORMS...AND IN
MILLER "A" STORMS INCLUDING THIS ONE...SUCH OCCURRENCE IS MOST
LIKELY NEAR THE NARROW TRANSITION SNOW/RAIN ZONE. NO APPRECIABLE
ICING IS ANTICIPATED...HOWEVER...IN PART SINCE SURFACE TEMPERATURES
ARE EXPECTED TO HOLD NEARLY STEADY IN THE 29 TO 33 DEGREE RANGE OVER
THE WARNING AREA...AND 32 TO 34 DEGREES OVER THE ADVISORY AREA WHERE
SUCH ICING OCCURRENCE WOULD BE MOST PROBABLE.
DESPITE SOME MINIMAL OVERALL RISE IN THICKNESS VALUES VERSUS THE
SLIGHTLY COLDER AND DRIER SOLUTIONS OF YESTERDAY...PROJECTED PARTIAL
THICKNESS VALUES OVER MOST OF THE PIEDMONT AND NORTHERN COASTAL
PLAIN REMAIN SQUARELY IN THE RANGE TYPICAL OF SIGNIFICANT SNOWSTORMS
IN CENTRAL NC. WITH A SLIGHTLY MILDER SOLUTION COMES A SLIGHTLY
WETTER ONE...LED BY A BLEND OF THE VERY SIMILAR 00Z ECMWF AND
GFS...SO QPF HAS BEEN RAISED TO AROUND ONE HALF INCH OVER THE NW
PIEDMONT TO AS MUCH AS ONE INCH OVER THE SOUTHERN COASTAL PLAIN.
PARTIAL THICKNESS VALUES HEAVILY WEIGHTED TOWARD THE FAVORED 00Z
ECMWF AND GFS...FAVORS MOSTLY SNOW OVER THE PIEDMONT AND NORTHERN
COASTAL PLAIN...WITH A MIX OF SNOW AND A COLD RAIN (OR FREEZING RAIN
WITH LITTLE ACCRUAL WHERE SFC TEMPERATURES OSCILLATE ABOUT THE
FREEZING MARK) OVER THE ADVISORY AREA.
SNOW RATIOS BETWEEN 00-06Z THU OF 10-14:1 PER WPC WWD SLR GUIDANCE
AND SUPPORTED BY THERMAL PROFILES THAT RANGE FROM DEEP NEAR FREEZING
ISOTHERMAL IN THER NARROW TRANSITION ZONE TO WELL BELOW FREEZING...
EXCEPT RIGHT AT THE SURFACE...ALONG AND NORTH OF THE I-40/I-85
CORRIDOR...ARE EXPECTED TO DECREASE PARTICULARLY NEAR NARROW
TRANSITION ZONE TO CLOSER TO 8-10:1 PER WHAT IS TYPICAL OF EVENTS
CHARACTERIZED BY PARTIAL THICKNESS VALUES IN THE ~1285/~1535 METER
RANGE. SLIGHTLY LOWER RATIOS...CLOSER TO 4-6:1 WITHIN THE SNOW/RAIN
TRANSITION ZONE - OR ROUGHLY ALONG THE BOUNDARY OF WINTER STORM
WARNING AND WINTER WEATHER ADVISORY - WHERE THE MIXING WITH A COLD
RAIN WILL RESULT IN A MORE SLUSHY ACCUMULATION VERSUS POINTS
NORTHWARD.
BASED ON THESE RATIOS...AND THE QPF NOTED ABOVE...WIDESPREAD
SNOWFALL ACCUMULATIONS OF 3 TO 6 INCHES ARE LIKELY OVER THE WARNING
AREA...WITH A STRIPE OF 6 TO 8 INCHES ROUGHLY INVOF OR JUST NORTH OF
THE US HIGHWAY 64 CORRIDOR...WITH LOCALLY HIGHER AMOUNTS FROM THE
TRIANGLE TO ROANOKE RAPIDS AND ROCKY MOUNT. MEANWHILE...LESSER
TOTALS OF 1 TO 3 INCHES ARE EXPECTED OVER THE ADVISORY AREA...WHERE
AGAIN...PARTIAL THICKNESS AND SFC TEMPERATURE VALUES MARGINALLY
ABOVE FREEZING WILL SUPPORT A MIXING WITH OR CHANGEOVER TO A COLD
RAIN BETWEEN MIDNIGHT AND 5 AM. EVEN THERE...HOWEVER...THE NORTHERN
PORTIONS OF THE ADVISORY COUNTIES MAY EXCEED WARNING CRITERIA OF 3
INCHES.
THE APPROACH OF A WEAK CLIPPER LOW AND ATTENDING SHORTWAVE TROUGH
WILL CAUSE THE LINGERING STRATUS LAYER AND ASSOCIATED MOSTLY CLOUDY
SKIES TO PRODUCE OCCASIONAL DRIZZLE OR FREEZING DRIZZLE...AFTER
LINGERING LIGHT SNOW...OWING TO A LOSS OF SATURATION ALOFT/IN THE
ICE NUCLEATION ZONE - BUT WITH MINIMAL ADDITIONAL IMPACT. CHILLY
TEMPERATURES IN THE LOWER TO MIDDLE 30S.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
AS OF 320 PM WEDNESDAY...
A MID-LEVEL SHORTWAVE IS FORECAST BY BOTH THE GFS AND THE NAM TO
MOVE THROUGH CENTRAL NORTH CAROLINA THURSDAY EVENING...WITH ANOTHER
WEAK WAVE ON FRIDAY. LOW-LEVEL MOISTURE REMAINS IN PLACE OVERALL...
HIGHLIGHTED BY MODEST VALUES OF MEAN RELATIVE HUMIDITY IN THE 1000-
500MB LAYER AS SURFACE HIGH PRESSURE GRADUALLY BUILDS IN. 850MB
THETA-E IS GENERALLY LOW DURING THE PERIOD WITH PRECIPITABLE WATER
VALUES AT OR JUST BELOW NORMAL FOR LATE FEBRUARY...HOWEVER...VIEWING
THE NAM AND GFS BUFR SOUNDINGS...AGAIN...LOW-LEVEL MOISTURE REMAINS
WITH SOME MOISTURE SATURATION AT TIMES TO AT OR JUST COLDER THAN -
10C. THE GFS IN PARTICULAR PROVIDES FOR MARGINAL MEASURABLE
PRECIPITATION IN THE FAR NORTHWEST PIEDMONT OVERNIGHT THURSDAY...
AND THEN MAINLY ALONG AND WEST OF U.S. 1 FRIDAY SHIFTING BACK WEST
AGAIN FRIDAY NIGHT INTO EARLY SATURDAY. IT IS DURING THESE PERIODS
THAT BUFR SOUNDINGS FORECAST MOISTURE TO A LEVEL IN ATMOSPHERE
COLDER THAN -10C.
LIFT IS MARGINAL DURING THIS SHORT-TERM PERIOD...LIKELY BEST ON
FRIDAY WHEN BUFR SOUNDINGS SHOW LOW-LEVEL LAPSE RATES STEEPENING AND
THE COMBINATION OF 850MB CONVERGENCE AND UPPER-LEVEL DIVERGENCE IS
BEST MAINLY OVER THE FAR NORTHWEST PIEDMONT OVERNIGHT THURSDAY AND
ALONG AND WEST OF U.S. 1 FRIDAY. GIVEN THE LOW-LEVEL MOISTURE AND
MODEST SUPPORT ALOFT WITH THE MID-LEVEL SHORTWAVES...IN ADDITION TO
THE GFS VERY LIGHT QPF AND SOME NOTICE OF LIGHT PRECIPITATION OUTPUT
ON THE NCEP HIGH RES NMMB...HAVE OPTED TO INCLUDE A SLIGHT CHANCE OF
FLURRIES MAINLY IN THE FAR NORTHWEST PIEDMONT THURSDAY NIGHT...WITH
A SLIGHT CHANCE OF SNOW SHOWERS THERE FRIDAY WHERE BUFR SOUNDINGS
ESPECIALLY ON THE GFS SHOW THE LAPSE RATES STEEPENING. A SLIGHT
CHANCE OF FLURRIES ELSEWHERE FRIDAY TO NEAR U.S. 1 OR SO...THEN A
SLIGHT CHANCE OF FLURRIES FRIDAY NIGHT ALONG AND NORTH OF A LINE
FROM ABOUT KRWI TO KAFP. BY SATURDAY MORNING...BUFR SOUNDINGS SHOW
ENOUGH DRYING THAT ANY FLURRIES THAT EXIST SHOULD ONLY BE LOCATED
OVER THE FAR NORTHWEST PIEDMONT. TOWARD KFAY...BUFR SOUNDINGS FROM
THE GFS AND NAM DO NOT SHOW DEEPER LOW-LEVEL MOISTURE GETTING TO OR
COLDER THAN -10C...SO HAVE NOT MENTIONED ANY FLURRIES THERE THIS
PERIOD. CURRENTLY THINK THERE SHOULD BE LITTLE OR NO IMPACT AS THE
PRECIPITATION SHOULD BE VERY LIGHT IF IT OCCURS...THOUGH STILL
NOTICEABLE. SATURDAY DURING THE DAY...HIGH PRESSURE CONTINUES TO
BUILD IN.
AFTER LOWS THURSDAY NIGHT IN THE 20S...HIGHS FRIDAY SHOULD RANGE
WITHIN A DEGREE OR THREE EITHER SIDE OF 40...CLOSE TO WHAT WOULD BE
ASSOCIATED WITH THE 1000-850MB THICKNESSES. LOWS FRIDAY NIGHT IN THE
UPPER TEENS TO MID 20S...A BLEND OF GUIDANCE BASED ON CONTINUED
CLOUD COVER. ON SATURDAY...A LITTLE COLDER THAN FRIDAY DUE TO COLDER
THICKNESSES TO START THE DAY AND THE HIGH BUILDING IN...MOSTLY MID
30S.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 1200 PM WEDNESDAY...
THE LONG-TERM SATURDAY NIGHT THROUGH WEDNESDAY IS CATEGORIZED BY
SOME UNCERTAINTY IN PRECIPITATION TIMING AND TYPE...WITH AT LEAST
MODEST CONFIDENCE IN MUCH WARMER TEMPERATURES DEVELOPING BY THE END
OF THIS PERIOD THAN WHAT HAS BEEN OCCURRING RECENTLY. DRYING IS
FORECAST FOR SATURDAY NIGHT...WITH A MID-LEVEL SHORTWAVE MOVING INTO
THE CAROLINAS BY SUNDAY NIGHT. AS HEIGHTS ALOFT RISE LATE IN THE
WEEKEND AND EARLY NEXT WEEK...THE 06Z GFS IN PARTICULAR AND POSSIBLY
EVEN THE 12Z GFS SEEMS TO HAVE ISSUES WITH FEEDBACK SUCH THAT THE
ECMWF IS PREFERRED OVERALL. IT SHOULD BE COLD TO START SUNDAY
MORNING AS CLOUDS INCREASE...BUT THE GFS AND ECMWF TREND OF A LATER
ARRIVAL OF MID-LEVEL VORTICITY AND OVERALL MOISTURE INCREASE SHOULD
RESULT IN PRECIPITATION BEING IN THE FORM OF LIQUID BY THE TIME ANY
WOULD ARRIVE LATER IN THE DAY. PARTIAL THICKNESSES AND MODEL
SOUNDINGS CURRENTLY SUPPORT THIS...AND WILL HAVE A CHANCE OF
AFTERNOON RAIN SUNDAY PRIMARILY TOWARD THE YADKIN RIVER FOLLOWED BY
CHANCES OF RAIN OVERNIGHT...WITH SURFACE TEMPERATURES REMAINING
ABOVE FREEZING AND MODEL SOUNDINGS SHOWING WARMING ALOFT AS 1000-
850MB THICKNESSES RISE AROUND 20M DURING THE NIGHT...SUGGESTING THE
POTENTIAL FOR LOW TEMPERATURES EARLY SUNDAY NIGHT FOLLOWED BY STEADY
OR A SLOW RISE IN READINGS LATE.
A BRIEF WARMUP OCCURS MONDAY AHEAD OF A COLD FRONT THAT MOVES
THROUGH CENTRAL NORTH CAROLINA LATER IN THE DAY AND AT NIGHT. STRONG
HIGH PRESSURE BUILDS IN BEHIND THE COLD FRONT...AND THE PATTERN
WOULD SUGGEST PRETTY CHILLY TEMPERATURES ONCE AGAIN WITH THE 1000-
850MB THICKNESSES SUGGESTING LOWS A LITTLE BELOW FREEZING. MOS
GUIDANCE LOWS ARE AT LEAST ONE IF NOT MORE CATEGORIES ABOVE THIS...
SO FOR NOW WILL SIMPLY UNDERCUT GUIDANCE WITH OVERNIGHT LOWS AT OR
SLIGHTLY ABOVE FREEZING. CONDITIONS SHOULD DRY BRIEFLY BEHIND THE
FRONT AS HIGH PRESSURE BUILDS IN...THEN UNCERTAINTY INCREASES AS THE
GFS AND THE ECMWF SUGGEST MOISTURE RETURNING TO CENTRAL NORTH
CAROLINA AS THE GULF OPENS BY TUESDAY INTO TUESDAY NIGHT. IF
PRECIPITATION WOULD RETURN TO CENTRAL NORTH CAROLINA QUICKLY ENOUGH
ON TUESDAY...PRECIPITATION TYPE CONCERNS WOULD EXIST DUE TO CHILLY
THICKNESSES TO START THE DAY. BY 00Z WEDNESDAY ON THE 12Z GFS...AND
FOR THE MOST PART ON THE 00Z ECMWF...THICKNESSES ARE WARM ENOUGH FOR
RAIN AND BASED ON THE WARM-AIR ADVECTION AT THE TIME WOULD
ANTICIPATE ANOTHER POTENTIAL NON-DIURNAL TEMPERATURE SCENARIO AS ANY
COLD-AIR DAMMING ERODES. BASED ON THE PATTERN WILL ONLY NOTE A
SLIGHT CHANCE OF RAIN OR SNOW EARLY ON THE SIXTH DAY IN THE WESTERN
PIEDMONT WITH A CHANCE OF JUST ALL RAIN THROUGHOUT CENTRAL NORTH
CAROLINA BY TUESDAY AFTERNOON. 1000-850MB THICKNESSES ON THE 12Z GFS
AND 00Z ECMWF ARE QUITE WARM WEDNESDAY...APPROACHING 1380M ON THE
LATEST GFS AND ONLY SLIGHTLY COOLER ON THE 00Z ECMWF...SUCH THAT...
WITH SHOWERY CONDITIONS IN A MOIST AIR MASS AND A SOUTHWEST FLOW
ALOFT...HIGH TEMPERATURES COULD POSSIBLY REACH THE 60S THROUGHOUT
CENTRAL NORTH CAROLINA WITH SOME TEMPERATURES PUSHING 70F ESPECIALLY
OVER PARTS OF THE SANDHILLS AND SOUTHERN COASTAL PLAIN.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AS OF 1255 PM WEDNESDAY...
FOR THE 18Z VALID TAF PERIOD...HIGH CONFIDENCE IN VFR CONDITIONS FOR
THE REST OF THIS AFTERNOON DETERIORATING QUICKLY TO IFR AND SUB-IFR
CONDITIONS THIS EVENING...CONTINUING OVERNIGHT. GUIDANCE SUGGESTS
PRECIPITATION MOVING SOUTHWEST TO NORTHEAST INTO AND ACROSS CENTRAL
NORTH CAROLINA FROM VERY LATE THIS AFTERNOON THROUGH THIS EVENING...
WITH PRECIPITATION ACROSS THE AREA BY 03Z. MODEL SOUNDINGS FROM THE
NAM AND GFS SUGGEST WHATEVER LIQUID PRECIPITATION THERE MAY BE TO
START CHANGING QUICKLY TO SNOW...WITH ENOUGH WARMING ALOFT THAT A
PRECIPITATION TYPE OF SNOW AND SLEET IS QUITE POSSIBLE AT KRDU AND
KRWI. AT KFAY...THE ABOVE FREEZING DEPTH IS A LITTLE HIGHER AND
LIGHT RAIN MAY LINGER A LITTLE LONGER AT THE START BEFORE A
TRANSITION TO SNOW...SLEET...AND FREEZING RAIN...WITH THE NAM MODEL
MOST SUGGESTIVE OF WARMTH ALOFT FOR FREEZING RAIN AND MAINLY FOR A
COUPLE OR THREE HOURS CENTERED AROUND 06Z. DRYING ALOFT VERY LATE
TONIGHT INTO THURSDAY MORNING SUGGEST PRECIPITATION CHANGING TO
FREEZING DRIZZLE OR DRIZZLE...WITH IFR CONDITIONS CONTINUING IN LOW
CLOUDS. VARIABLE WINDS THIS AFTERNOON BECOME NORTH-NORTHEAST AND
NORTHEAST THIS EVENING AS LOW PRESSURE GETS CLOSER AND MOVES
NORTHEAST ALONG THE ATLANTIC COAST.
BEYOND THE 18Z VALID TAF PERIOD...CONFIDENCE DIMINISHES IN
IMPROVEMENT FROM IFR CONDITIONS...WITH AVIATION INTERESTS BEING
PREPARED FOR THE LIKELIHOOD OF SUB-VFR CONDITIONS THROUGH THURSDAY
NIGHT ALBEIT WITH A FEW PERIODS OF VFR CONDITIONS POSSIBLE MAINLY
THURSDAY NIGHT. SUB-VFR CONDITIONS REMAIN POSSIBLE IN LOW CLOUDS
THROUGH FRIDAY WITH A GREATER LIKELIHOOD OF VFR CONDITIONS FOR
FRIDAY NIGHT. VFR CONDITIONS EXPECTED SATURDAY WITH CLOUDS
INCREASING AND LOWERING FOR SUNDAY...THEN SUB-VFR CONDITIONS LIKELY
FOR SUNDAY NIGHT INTO MONDAY ALONG WITH CHANCES FOR PRECIPITATION.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO NOON EST THURSDAY
FOR NCZ078-085-086-088-089.
WINTER STORM WARNING FROM 6 PM THIS EVENING TO NOON EST THURSDAY FOR
NCZ007>011-021>028-038>043-073>077-083-084.
&&
$$
SYNOPSIS...RAH
NEAR TERM...BLAES/RAH
SHORT TERM...DJF
LONG TERM...DJF
AVIATION...DJF
AREA FORECAST DISCUSSION
NWS RALEIGH NC
150 PM EST WED FEB 25 2015
.SYNOPSIS...AN AREA OF LOW PRESSURE MOVES QUICKLY FROM THE NORTHERN
GULF OF MEXICO...TO OFF THE CAROLINA COAST OVERNIGHT THROUGH EARLY
THURSDAY. COLD CANADIAN HIGH PRESSURE THEN BUILDS INTO THE REGION
FRIDAY AND INTO THE WEEKEND.
&&
.NEAR TERM /TODAY/...
AS OF 150 PM WEDNESDAY...
UPDATED THE DISCUSSION ONLY TO REMOVE MENTION OF THE EARLIER
ADVISORY.
MORNING UPPER AIR ANALYSIS SHOWS THE SHEARING SHORT WAVE
TROUGH OVER TEXAS THIS MORNING WITH SHORT WAVE RIDGING OUT AHEAD OF
IT ACROSS THE SOUTHEAST. HIGH CLOUDS HAVE BEEN ADVANCING NORTHEAST
AHEAD OF THE SYSTEM AND MOST OF CENTRAL NC IS ALREADY UNDER AT LEAST
A THIN VEIL OF CIRRUS. REGIONAL RADAR IMAGERY SHOWS PRECIPITATION
EXPANDING ACROSS THE DEEP SOUTH WITH MEASURABLE PRECIP NOW REPORTED
ACROSS CENTRAL ALABAMA. NO PRECIPITATION IS EXPECTED IN CENTRAL NC
DURING THE TODAY PERIOD BUT TODAYS WEATHER COULD STILL PLAY A ROLE IN
THE IMPACT OF TONIGHTS WINTER STORM. THE TEMPERATURES FORECAST FOR
TODAY IS PROBLEMATIC AS YESTERDAYS SNOWFALL WILL DAMPEN THE
TEMPERATURE RECOVERY THIS AFTERNOON AND ENERGY IS DIVERTED INTO
MELTING AND EVAPORATING SNOW AND MELT WATER. EVEN SO...SOME
GUIDANCE INCLUDING THE HRRR SUGGEST HIGHS IN THE MID 40S TO AROUND
50. NOT READY TO JUMP THAT HIGH BUT CURRENT TEMP AT OUR OFFICE IS 37
AT 1045 AND HAVE MADE A SLIGHT UPWARD ADJUSTMENT IN TEMPERATURES FOR
TODAY. THIS UPWARD TREND IN BOUNDARY LAYER TEMPERATURES WOULD
DELAY THE CHANGEOVER FROM RAIN OR MIXED RAIN AND SNOW THIS EVENING
TO SNOW AND POTENTIALLY LIMIT ACCUMULATIONS A BIT...PRIMARILY
ACROSS THE FAR SOUTHERN TIER IN THE SANDHILLS AND SOUTHERN COASTAL
PLAIN. -BLAES
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY/...
AS OF 1100 AM WEDNESDAY...
*** QUICK 1100 AM UPDATE. QUICK LOOK AT 12Z GUIDANCE NOTES NO
IMMEDIATE OR SIGNIFICANT FORECAST ADJUSTMENTS ARE NEEDED BUT NAM
CONTINUES TO TREND NORTH A BIT AND WITH THE GFS SHOWING A SLIGHT
NORTHWARD ADJUSTMENT.
...WINTER STORM WARNING HAS BEEN ISSUED FOR TONIGHT AND THURSDAY FOR
ALL THE PIEDMONT...NORTHERN/CENTRAL COASTAL PLAIN AND SANDHILLS...
...WINTER WEATHER ADVISORY HAS BEEN ISSUED FOR TONIGHT AND THURSDAY
FOR THE SOUTHERN COASTAL PLAIN...
THERE HAS BEEN A CONTINUED SLIGHT NORTHWARD SHIFT IN GUIDANCE SINCE
YESTERDAY...WHICH EQUATES TO A WETTER AND MARGINALLY WARMER SOLUTION
FOR CENTRAL NC...THOUGH THE OVERALL PATTERN REMAINS UNCHANGED WITH
THE DEAMPLIFICATION/ENE SHEARING OF A SHORTWAVE TROUGH FROM NEAR THE
RIO GRANDE THIS MORNING TO THE MIDDLE ATLANTIC COAST BY THU MORNING.
THE ASSOCIATED FORCING FOR ASCENT ATOP A PAIR OF CLOSELY-SPACED AND
STRONG FRONTAL ZONES DRAPED ACROSS THE NORTHERN GOM TO A SFC LOW
ABOUT MIDWAY BETWEEN CAPE HATTERAS AND BERMUDA...WILL RESULT IN THE
CONTINUED DEEPENING OF A SFC LOW OVER THE NW GOM THIS MORNING.
GUIDANCE IS THEN FAIRLY TIGHTLY CLUSTERED WITH THE TRACK OF A MILLER
"A" SFC LOW ACROSS THE NORTHERN FL PENINSULA THIS EVENING AND
ROUGHLY ALONG THE GULF STREAM TO JUST EAST OF CAPE HATTERAS BY 12Z
THU.
AS HAS BEEN NOTED IN PREVIOUS DISCUSSIONS...THE LACK OF A PARENT
COLD HIGH IS ADMITTEDLY SOMEWHAT CONCERNING. AN ARCTIC SFC HIGH AT
1045 MB WILL BE CENTERED OVER SOUTHERN ALBERTA/SASKATCHEWAN AND WILL
CONSEQUENTLY HAVE LITTLE INFLUENCE AT OUR LATITUDE DURING THE HEIGHT
OF THE STORM TONIGHT. HOWEVER...A VERY FAVORABLE MILLER "A" CYCLONE
TRACK ALONG AND JUST OFFSHORE THE SE COAST...IN CONJUNCTION WITH A
PRECEDING ARCTIC HIGH THAT APPEARS TO BE JUST COLD ENOUGH DESPITE
BEING IN A DRAMATICALLY WEAKENED STATE FROM A COUPLE OF DAYS
AGO...BUT IS STILL CHARACTERIZED BY SFC TEMPERATURES AND DEWPOINTS
MOSTLY IN THE TEENS TO 20S OVER NC THIS MORNING...WILL SUPPORT A
SIGNIFICANT WINTER STORM **WITH A NARROW P-TYPE (SNOW/RAIN)
TRANSITION ZONE AND DEEP NEAR FREEZING ISOTHERMAL PROFILES
CHARACTERISTIC OF MILLER "A` SFC PATTERNS.** PRECIPITATION
RATES...OCCASIONALLY MODERATE TO HEAVY...WILL ONLY SERVE TO ENHANCE
THE DEEP NEAR FREEZING ISOTHERMAL PROFILES RIGHT ALONG THE SNOW/COLD
RAIN INTERFACE...OWING TO MELTING. A LITTLE MIX OF SLEET AND
FREEZING RAIN ARE HARD TO AVOID IN CENTRAL NC WINTER STORMS...AND IN
MILLER "A" STORMS INCLUDING THIS ONE...SUCH OCCURRENCE IS MOST LIKELY
NEAR THE NARROW TRANSITION SNOW/RAIN ZONE. NO APPRECIABLE ICING IS
ANTICIPATED...HOWEVER...IN PART SINCE SURFACE TEMPERATURES ARE
EXPECTED TO HOLD NEARLY STEADY IN THE 29 TO 33 DEGREE RANGE OVER THE
WARNING AREA...AND 32 TO 34 DEGREES OVER THE ADVISORY AREA WHERE
SUCH ICING OCCURRENCE WOULD BE MOST PROBABLE.
DESPITE SOME MINIMAL OVERALL RISE IN THICKNESS VALUES VERSUS THE
SLIGHTLY COLDER AND DRIER SOLUTIONS OF YESTERDAY...PROJECTED PARTIAL
THICKNESS VALUES OVER MOST OF THE PIEDMONT AND NORTHERN COASTAL
PLAIN REMAIN SQUARELY IN THE RANGE TYPICAL OF SIGNIFICANT SNOWSTORMS
IN CENTRAL NC. WITH A SLIGHTLY MILDER SOLUTION COMES A SLIGHTLY
WETTER ONE...LED BY A BLEND OF THE VERY SIMILAR 00Z ECMWF AND
GFS...SO QPF HAS BEEN RAISED TO AROUND ONE HALF INCH OVER THE NW
PIEDMONT TO AS MUCH AS ONE INCH OVER THE SOUTHERN COASTAL PLAIN.
PARTIAL THICKNESS VALUES HEAVILY WEIGHTED TOWARD THE FAVORED 00Z
ECMWF AND GFS...FAVORS MOSTLY SNOW OVER THE PIEDMONT AND NORTHERN
COASTAL PLAIN...WITH A MIX OF SNOW AND A COLD RAIN (OR FREEZING RAIN
WITH LITTLE ACCRUAL WHERE SFC TEMPERATURES OSCILLATE ABOUT THE
FREEZING MARK) OVER THE ADVISORY AREA.
SNOW RATIOS BETWEEN 00-06Z THU OF 10-14:1 PER WPC WWD SLR GUIDANCE
AND SUPPORTED BY THERMAL PROFILES THAT RANGE FROM DEEP NEAR FREEZING
ISOTHERMAL IN THER NARROW TRANSITION ZONE TO WELL BELOW FREEZING...
EXCEPT RIGHT AT THE SURFACE...ALONG AND NORTH OF THE I-40/I-85
CORRIDOR...ARE EXPECTED TO DECREASE PARTICULARLY NEAR NARROW
TRANSITION ZONE TO CLOSER TO 8-10:1 PER WHAT IS TYPICAL OF EVENTS
CHARACTERIZED BY PARTIAL THICKNESS VALUES IN THE ~1285/~1535 METER
RANGE. SLIGHTLY LOWER RATIOS...CLOSER TO 4-6:1 WITHIN THE SNOW/RAIN
TRANSITION ZONE - OR ROUGHLY ALONG THE BOUNDARY OF WINTER STORM
WARNING AND WINTER WEATHER ADVISORY - WHERE THE MIXING WITH A COLD
RAIN WILL RESULT IN A MORE SLUSHY ACCUMULATION VERSUS POINTS
NORTHWARD.
BASED ON THESE RATIOS...AND THE QPF NOTED ABOVE...WIDESPREAD
SNOWFALL ACCUMULATIONS OF 3 TO 6 INCHES ARE LIKELY OVER THE WARNING
AREA...WITH A STRIPE OF 6 TO 8 INCHES ROUGHLY INVOF OR JUST NORTH OF
THE US HIGHWAY 64 CORRIDOR...WITH LOCALLY HIGHER AMOUNTS FROM THE
TRIANGLE TO ROANOKE RAPIDS AND ROCKY MOUNT. MEANWHILE...LESSER
TOTALS OF 1 TO 3 INCHES ARE EXPECTED OVER THE ADVISORY AREA...WHERE
AGAIN...PARTIAL THICKNESS AND SFC TEMPERATURE VALUES MARGINALLY
ABOVE FREEZING WILL SUPPORT A MIXING WITH OR CHANGEOVER TO A COLD
RAIN BETWEEN MIDNIGHT AND 5 AM. EVEN THERE...HOWEVER...THE NORTHERN
PORTIONS OF THE ADVISORY COUNTIES MAY EXCEED WARNING CRITERIA OF 3
INCHES.
THE APPROACH OF A WEAK CLIPPER LOW AND ATTENDING SHORTWAVE TROUGH
WILL CAUSE THE LINGERING STRATUS LAYER AND ASSOCIATED MOSTLY CLOUDY
SKIES TO PRODUCE OCCASIONAL DRIZZLE OR FREEZING DRIZZLE...AFTER
LINGERING LIGHT SNOW...OWING TO A LOSS OF SATURATION ALOFT/IN THE
ICE NUCLEATION ZONE - BUT WITH MINIMAL ADDITIONAL IMPACT. CHILLY
TEMPERATURES IN THE LOWER TO MIDDLE 30S.
&&
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
AS OF 1200 PM WEDNESDAY...
SHORTWAVE DISTURBANCES EMBEDDED IN THE CONTINUED SWLY FLOW ALOFT AND
LINGERING LOW-LEVEL MOISTURE OWING TO WHAT WILL LIKELY BE A MOIST
SNOW COVER GROUND(AT LEAST FOR THE NORTHERN TWO-THIRDS OF THE
FORECAST AREA)...WILL RESULT IN RATHER EXTENSIVE CLOUDINESS INTO
SATURDAY. COMBINATION OF THIS CLOUD COVER...SNOW COVER AND THE
ARRIVAL OF ANOTHER FRESH SUPPLY OF ARCTIC AIR INTO THE REGION LATE
THURSDAY NIGHT AND INTO FRIDAY...AS A STRONG +1040MB CANADIAN
SURFACE HIGH BUILDS OVER THE REGION...WILL SUPPORT TEMPERATURES WELL
BELOW NORMAL(15-20 DEGREES FRIDAY AND SATURDAY. DRY WITH HIGHS IN
THE MID 30S NORTH TO POSSIBLY LOWER 40S SOUTH...WITH SATURDAY BEING
THE COLDEST DAY OF THE TWO. -CBL
THE LONG-TERM SATURDAY NIGHT THROUGH WEDNESDAY IS CATEGORIZED BY
SOME UNCERTAINTY IN PRECIPITATION TIMING AND TYPE...WITH AT LEAST
MODEST CONFIDENCE IN MUCH WARMER TEMPERATURES DEVELOPING BY THE END
OF THIS PERIOD THAN WHAT HAS BEEN OCCURRING RECENTLY. DRYING IS
FORECAST FOR SATURDAY NIGHT...WITH A MID-LEVEL SHORTWAVE MOVING INTO
THE CAROLINAS BY SUNDAY NIGHT. AS HEIGHTS ALOFT RISE LATE IN THE
WEEKEND AND EARLY NEXT WEEK...THE 06Z GFS IN PARTICULAR AND POSSIBLY
EVEN THE 12Z GFS SEEMS TO HAVE ISSUES WITH FEEDBACK SUCH THAT THE
ECMWF IS PREFERRED OVERALL. IT SHOULD BE COLD TO START SUNDAY
MORNING AS CLOUDS INCREASE...BUT THE GFS AND ECMWF TREND OF A LATER
ARRIVAL OF MID-LEVEL VORTICITY AND OVERALL MOISTURE INCREASE SHOULD
RESULT IN PRECIPITATION BEING IN THE FORM OF LIQUID BY THE TIME ANY
WOULD ARRIVE LATER IN THE DAY. PARTIAL THICKNESSES AND MODEL
SOUNDINGS CURRENTLY SUPPORT THIS...AND WILL HAVE A CHANCE OF
AFTERNOON RAIN SUNDAY PRIMARILY TOWARD THE YADKIN RIVER FOLLOWED BY
CHANCES OF RAIN OVERNIGHT...WITH SURFACE TEMPERATURES REMAINING
ABOVE FREEZING AND MODEL SOUNDINGS SHOWING WARMING ALOFT AS 1000-
850MB THICKNESSES RISE AROUND 20M DURING THE NIGHT...SUGGESTING THE
POTENTIAL FOR LOW TEMPERATURES EARLY SUNDAY NIGHT FOLLOWED BY STEADY
OR A SLOW RISE IN READINGS LATE.
A BRIEF WARMUP OCCURS MONDAY AHEAD OF A COLD FRONT THAT MOVES
THROUGH CENTRAL NORTH CAROLINA LATER IN THE DAY AND AT NIGHT. STRONG
HIGH PRESSURE BUILDS IN BEHIND THE COLD FRONT...AND THE PATTERN
WOULD SUGGEST PRETTY CHILLY TEMPERATURES ONCE AGAIN WITH THE 1000-
850MB THICKNESSES SUGGESTING LOWS A LITTLE BELOW FREEZING. MOS
GUIDANCE LOWS ARE AT LEAST ONE IF NOT MORE CATEGORIES ABOVE THIS...
SO FOR NOW WILL SIMPLY UNDERCUT GUIDANCE WITH OVERNIGHT LOWS AT OR
SLIGHTLY ABOVE FREEZING. CONDITIONS SHOULD DRY BRIEFLY BEHIND THE
FRONT AS HIGH PRESSURE BUILDS IN...THEN UNCERTAINTY INCREASES AS THE
GFS AND THE ECMWF SUGGEST MOISTURE RETURNING TO CENTRAL NORTH
CAROLINA AS THE GULF OPENS BY TUESDAY INTO TUESDAY NIGHT. IF
PRECIPITATION WOULD RETURN TO CENTRAL NORTH CAROLINA QUICKLY ENOUGH
ON TUESDAY...PRECIPITATION TYPE CONCERNS WOULD EXIST DUE TO CHILLY
THICKNESSES TO START THE DAY. BY 00Z WEDNESDAY ON THE 12Z GFS...AND
FOR THE MOST PART ON THE 00Z ECMWF...THICKNESSES ARE WARM ENOUGH FOR
RAIN AND BASED ON THE WARM-AIR ADVECTION AT THE TIME WOULD
ANTICIPATE ANOTHER POTENTIAL NON-DIURNAL TEMPERATURE SCENARIO AS ANY
COLD-AIR DAMMING ERODES. BASED ON THE PATTERN WILL ONLY NOTE A
SLIGHT CHANCE OF RAIN OR SNOW EARLY ON THE SIXTH DAY IN THE WESTERN
PIEDMONT WITH A CHANCE OF JUST ALL RAIN THROUGHOUT CENTRAL NORTH
CAROLINA BY TUESDAY AFTERNOON. 1000-850MB THICKNESSES ON THE 12Z GFS
AND 00Z ECMWF ARE QUITE WARM WEDNESDAY...APPROACHING 1380M ON THE
LATEST GFS AND ONLY SLIGHTLY COOLER ON THE 00Z ECMWF...SUCH THAT...
WITH SHOWERY CONDITIONS IN A MOIST AIR MASS AND A SOUTHWEST FLOW
ALOFT...HIGH TEMPERATURES COULD POSSIBLY REACH THE 60S THROUGHOUT
CENTRAL NORTH CAROLINA WITH SOME TEMPERATURES PUSHING OR EXCEEDING
70F ESPECIALLY OVER PARTS OF THE SANDHILLS AND SOUTHERN COASTAL
PLAIN. -DJF
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AS OF 1255 PM WEDNESDAY...
FOR THE 18Z VALID TAF PERIOD...HIGH CONFIDENCE IN VFR CONDITIONS FOR
THE REST OF THIS AFTERNOON DETERIORATING QUICKLY TO IFR AND SUB-IFR
CONDITIONS THIS EVENING...CONTINUING OVERNIGHT. GUIDANCE SUGGESTS
PRECIPITATION MOVING SOUTHWEST TO NORTHEAST INTO AND ACROSS CENTRAL
NORTH CAROLINA FROM VERY LATE THIS AFTERNOON THROUGH THIS EVENING...
WITH PRECIPITATION ACROSS THE AREA BY 03Z. MODEL SOUNDINGS FROM THE
NAM AND GFS SUGGEST WHATEVER LIQUID PRECIPITATION THERE MAY BE TO
START CHANGING QUICKLY TO SNOW...WITH ENOUGH WARMING ALOFT THAT A
PRECIPITATION TYPE OF SNOW AND SLEET IS QUITE POSSIBLE AT KRDU AND
KRWI. AT KFAY...THE ABOVE FREEZING DEPTH IS A LITTLE HIGHER AND
LIGHT RAIN MAY LINGER A LITTLE LONGER AT THE START BEFORE A
TRANSITION TO SNOW...SLEET...AND FREEZING RAIN...WITH THE NAM MODEL
MOST SUGGESTIVE OF WARMTH ALOFT FOR FREEZING RAIN AND MAINLY FOR A
COUPLE OR THREE HOURS CENTERED AROUND 06Z. DRYING ALOFT VERY LATE
TONIGHT INTO THURSDAY MORNING SUGGEST PRECIPITATION CHANGING TO
FREEZING DRIZZLE OR DRIZZLE...WITH IFR CONDITIONS CONTINUING IN LOW
CLOUDS. VARIABLE WINDS THIS AFTERNOON BECOME NORTH-NORTHEAST AND
NORTHEAST THIS EVENING AS LOW PRESSURE GETS CLOSER AND MOVES
NORTHEAST ALONG THE ATLANTIC COAST.
BEYOND THE 18Z VALID TAF PERIOD...CONFIDENCE DIMINISHES IN
IMPROVEMENT FROM IFR CONDITIONS...WITH AVIATION INTERESTS BEING
PREPARED FOR THE LIKELIHOOD OF SUB-VFR CONDITIONS THROUGH THURSDAY
NIGHT ALBEIT WITH A FEW PERIODS OF VFR CONDITIONS POSSIBLE MAINLY
THURSDAY NIGHT. SUB-VFR CONDITIONS REMAIN POSSIBLE IN LOW CLOUDS
THROUGH FRIDAY WITH A GREATER LIKELIHOOD OF VFR CONDITIONS FOR
FRIDAY NIGHT. VFR CONDITIONS EXPECTED SATURDAY WITH CLOUDS
INCREASING AND LOWERING FOR SUNDAY...THEN SUB-VFR CONDITIONS LIKELY
FOR SUNDAY NIGHT INTO MONDAY ALONG WITH CHANCES FOR PRECIPITATION.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO NOON EST THURSDAY
FOR NCZ078-085-086-088-089.
WINTER STORM WARNING FROM 6 PM THIS EVENING TO NOON EST THURSDAY FOR
NCZ007>011-021>028-038>043-073>077-083-084.
&&
$$
SYNOPSIS...RAH
NEAR TERM...BLAES
SHORT TERM...BLAES/RAH
LONG TERM...CBL/DJF
AVIATION...DJF
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1255 PM EST WED FEB 25 2015
.SYNOPSIS...AN AREA OF LOW PRESSURE MOVES QUICKLY FROM THE NORTHERN
GULF OF MEXICO...TO OFF THE CAROLINA COAST OVERNIGHT THROUGH EARLY
THURSDAY. COLD CANADIAN HIGH PRESSURE THEN BUILDS INTO THE REGION
FRIDAY AND INTO THE WEEKEND.
&&
.NEAR TERM /TODAY/...
AS OF 1105 AM WEDNESDAY...
...WINTER WEATHER ADVISORY FOR BLACK ICE THROUGH NOON TODAY...
WILL CANCEL THE WINTER WEATHER ADVISORY SHORTLY.
MORNING UPPER AIR ANALYSIS SHOWS THE SHEARING SHORT WAVE
TROUGH OVER TEXAS THIS MORNING WITH SHORT WAVE RIDGING OUT AHEAD OF
IT ACROSS THE SOUTHEAST. HIGH CLOUDS HAVE BEEN ADVANCING NORTHEAST
AHEAD OF THE SYSTEM AND MOST OF CENTRAL NC IS ALREADY UNDER AT LEAST
A THIN VEIL OF CIRRUS. REGIONAL RADAR IMAGERY SHOWS PRECIPITATION
EXPANDING ACROSS THE DEEP SOUTH WITH MEASURABLE PRECIP NOW REPORTED
ACROSS CENTRAL ALABAMA. NO PRECIPITATION IS EXPECTED IN CENTRAL NC
DURING THE TODAY PERIOD BUT TODAYS WEATHER COULD STILL PLAY A ROLE IN
THE IMPACT OF TONIGHTS WINTER STORM. THE TEMPERATURES FORECAST FOR
TODAY IS PROBLEMATIC AS YESTERDAYS SNOWFALL WILL DAMPEN THE
TEMPERATURE RECOVERY THIS AFTERNOON AND ENERGY IS DIVERTED INTO
MELTING AND EVAPORATING SNOW AND MELT WATER. EVEN SO...SOME
GUIDANCE INCLUDING THE HRRR SUGGEST HIGHS IN THE MID 40S TO AROUND
50. NOT READY TO JUMP THAT HIGH BUT CURRENT TEMP AT OUR OFFICE IS 37
AT 1045 AND HAVE MADE A SLIGHT UPWARD ADJUSTMENT IN TEMPERATURES FOR
TODAY. THIS UPWARD TREND IN BOUNDARY LAYER TEMPERATURES WOULD
DELAY THE CHANGEOVER FROM RAIN OR MIXED RAIN AND SNOW THIS EVENING
TO SNOW AND POTENTIALLY LIMIT ACCUMULATIONS A BIT...PRIMARILY
ACROSS THE FAR SOUTHERN TIER IN THE SANDHILLS AND SOUTHERN COASTAL
PLAIN. -BLAES
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY/...
AS OF 1100 AM WEDNESDAY...
*** QUICK 1100 AM UPDATE. QUICK LOOK AT 12Z GUIDANCE NOTES NO
IMMEDIATE OR SIGNIFICANT FORECAST ADJUSTMENTS ARE NEEDED BUT NAM
CONTINUES TO TREND NORTH A BIT AND WITH THE GFS SHOWING A SLIGHT
NORTHWARD ADJUSTMENT.
...WINTER STORM WARNING HAS BEEN ISSUED FOR TONIGHT AND THURSDAY FOR
ALL THE PIEDMONT...NORTHERN/CENTRAL COASTAL PLAIN AND SANDHILLS...
...WINTER WEATHER ADVISORY HAS BEEN ISSUED FOR TONIGHT AND THURSDAY
FOR THE SOUTHERN COASTAL PLAIN...
THERE HAS BEEN A CONTINUED SLIGHT NORTHWARD SHIFT IN GUIDANCE SINCE
YESTERDAY...WHICH EQUATES TO A WETTER AND MARGINALLY WARMER SOLUTION
FOR CENTRAL NC...THOUGH THE OVERALL PATTERN REMAINS UNCHANGED WITH
THE DEAMPLIFICATION/ENE SHEARING OF A SHORTWAVE TROUGH FROM NEAR THE
RIO GRANDE THIS MORNING TO THE MIDDLE ATLANTIC COAST BY THU MORNING.
THE ASSOCIATED FORCING FOR ASCENT ATOP A PAIR OF CLOSELY-SPACED AND
STRONG FRONTAL ZONES DRAPED ACROSS THE NORTHERN GOM TO A SFC LOW
ABOUT MIDWAY BETWEEN CAPE HATTERAS AND BERMUDA...WILL RESULT IN THE
CONTINUED DEEPENING OF A SFC LOW OVER THE NW GOM THIS MORNING.
GUIDANCE IS THEN FAIRLY TIGHTLY CLUSTERED WITH THE TRACK OF A MILLER
"A" SFC LOW ACROSS THE NORTHERN FL PENINSULA THIS EVENING AND
ROUGHLY ALONG THE GULF STREAM TO JUST EAST OF CAPE HATTERAS BY 12Z
THU.
AS HAS BEEN NOTED IN PREVIOUS DISCUSSIONS...THE LACK OF A PARENT
COLD HIGH IS ADMITTEDLY SOMEWHAT CONCERNING. AN ARCTIC SFC HIGH AT
1045 MB WILL BE CENTERED OVER SOUTHERN ALBERTA/SASKATCHEWAN AND WILL
CONSEQUENTLY HAVE LITTLE INFLUENCE AT OUR LATITUDE DURING THE HEIGHT
OF THE STORM TONIGHT. HOWEVER...A VERY FAVORABLE MILLER "A" CYCLONE
TRACK ALONG AND JUST OFFSHORE THE SE COAST...IN CONJUNCTION WITH A
PRECEDING ARCTIC HIGH THAT APPEARS TO BE JUST COLD ENOUGH DESPITE
BEING IN A DRAMATICALLY WEAKENED STATE FROM A COUPLE OF DAYS
AGO...BUT IS STILL CHARACTERIZED BY SFC TEMPERATURES AND DEWPOINTS
MOSTLY IN THE TEENS TO 20S OVER NC THIS MORNING...WILL SUPPORT A
SIGNIFICANT WINTER STORM **WITH A NARROW P-TYPE (SNOW/RAIN)
TRANSITION ZONE AND DEEP NEAR FREEZING ISOTHERMAL PROFILES
CHARACTERISTIC OF MILLER "A` SFC PATTERNS.** PRECIPITATION
RATES...OCCASIONALLY MODERATE TO HEAVY...WILL ONLY SERVE TO ENHANCE
THE DEEP NEAR FREEZING ISOTHERMAL PROFILES RIGHT ALONG THE SNOW/COLD
RAIN INTERFACE...OWING TO MELTING. A LITTLE MIX OF SLEET AND
FREEZING RAIN ARE HARD TO AVOID IN CENTRAL NC WINTER STORMS...AND IN
MILLER "A" STORMS INCLUDING THIS ONE...SUCH OCCURRENCE IS MOST LIKELY
NEAR THE NARROW TRANSITION SNOW/RAIN ZONE. NO APPRECIABLE ICING IS
ANTICIPATED...HOWEVER...IN PART SINCE SURFACE TEMPERATURES ARE
EXPECTED TO HOLD NEARLY STEADY IN THE 29 TO 33 DEGREE RANGE OVER THE
WARNING AREA...AND 32 TO 34 DEGREES OVER THE ADVISORY AREA WHERE
SUCH ICING OCCURRENCE WOULD BE MOST PROBABLE.
DESPITE SOME MINIMAL OVERALL RISE IN THICKNESS VALUES VERSUS THE
SLIGHTLY COLDER AND DRIER SOLUTIONS OF YESTERDAY...PROJECTED PARTIAL
THICKNESS VALUES OVER MOST OF THE PIEDMONT AND NORTHERN COASTAL
PLAIN REMAIN SQUARELY IN THE RANGE TYPICAL OF SIGNIFICANT SNOWSTORMS
IN CENTRAL NC. WITH A SLIGHTLY MILDER SOLUTION COMES A SLIGHTLY
WETTER ONE...LED BY A BLEND OF THE VERY SIMILAR 00Z ECMWF AND
GFS...SO QPF HAS BEEN RAISED TO AROUND ONE HALF INCH OVER THE NW
PIEDMONT TO AS MUCH AS ONE INCH OVER THE SOUTHERN COASTAL PLAIN.
PARTIAL THICKNESS VALUES HEAVILY WEIGHTED TOWARD THE FAVORED 00Z
ECMWF AND GFS...FAVORS MOSTLY SNOW OVER THE PIEDMONT AND NORTHERN
COASTAL PLAIN...WITH A MIX OF SNOW AND A COLD RAIN (OR FREEZING RAIN
WITH LITTLE ACCRUAL WHERE SFC TEMPERATURES OSCILLATE ABOUT THE
FREEZING MARK) OVER THE ADVISORY AREA.
SNOW RATIOS BETWEEN 00-06Z THU OF 10-14:1 PER WPC WWD SLR GUIDANCE
AND SUPPORTED BY THERMAL PROFILES THAT RANGE FROM DEEP NEAR FREEZING
ISOTHERMAL IN THER NARROW TRANSITION ZONE TO WELL BELOW FREEZING...
EXCEPT RIGHT AT THE SURFACE...ALONG AND NORTH OF THE I-40/I-85
CORRIDOR...ARE EXPECTED TO DECREASE PARTICULARLY NEAR NARROW
TRANSITION ZONE TO CLOSER TO 8-10:1 PER WHAT IS TYPICAL OF EVENTS
CHARACTERIZED BY PARTIAL THICKNESS VALUES IN THE ~1285/~1535 METER
RANGE. SLIGHTLY LOWER RATIOS...CLOSER TO 4-6:1 WITHIN THE SNOW/RAIN
TRANSITION ZONE - OR ROUGHLY ALONG THE BOUNDARY OF WINTER STORM
WARNING AND WINTER WEATHER ADVISORY - WHERE THE MIXING WITH A COLD
RAIN WILL RESULT IN A MORE SLUSHY ACCUMULATION VERSUS POINTS
NORTHWARD.
BASED ON THESE RATIOS...AND THE QPF NOTED ABOVE...WIDESPREAD
SNOWFALL ACCUMULATIONS OF 3 TO 6 INCHES ARE LIKELY OVER THE WARNING
AREA...WITH A STRIPE OF 6 TO 8 INCHES ROUGHLY INVOF OR JUST NORTH OF
THE US HIGHWAY 64 CORRIDOR...WITH LOCALLY HIGHER AMOUNTS FROM THE
TRIANGLE TO ROANOKE RAPIDS AND ROCKY MOUNT. MEANWHILE...LESSER
TOTALS OF 1 TO 3 INCHES ARE EXPECTED OVER THE ADVISORY AREA...WHERE
AGAIN...PARTIAL THICKNESS AND SFC TEMPERATURE VALUES MARGINALLY
ABOVE FREEZING WILL SUPPORT A MIXING WITH OR CHANGEOVER TO A COLD
RAIN BETWEEN MIDNIGHT AND 5 AM. EVEN THERE...HOWEVER...THE NORTHERN
PORTIONS OF THE ADVISORY COUNTIES MAY EXCEED WARNING CRITERIA OF 3
INCHES.
THE APPROACH OF A WEAK CLIPPER LOW AND ATTENDING SHORTWAVE TROUGH
WILL CAUSE THE LINGERING STRATUS LAYER AND ASSOCIATED MOSTLY CLOUDY
SKIES TO PRODUCE OCCASIONAL DRIZZLE OR FREEZING DRIZZLE...AFTER
LINGERING LIGHT SNOW...OWING TO A LOSS OF SATURATION ALOFT/IN THE
ICE NUCLEATION ZONE - BUT WITH MINIMAL ADDITIONAL IMPACT. CHILLY
TEMPERATURES IN THE LOWER TO MIDDLE 30S.
&&
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
AS OF 1200 PM WEDNESDAY...
SHORTWAVE DISTURBANCES EMBEDDED IN THE CONTINUED SWLY FLOW ALOFT AND
LINGERING LOW-LEVEL MOISTURE OWING TO WHAT WILL LIKELY BE A MOIST
SNOW COVER GROUND(AT LEAST FOR THE NORTHERN TWO-THIRDS OF THE
FORECAST AREA)...WILL RESULT IN RATHER EXTENSIVE CLOUDINESS INTO
SATURDAY. COMBINATION OF THIS CLOUD COVER...SNOW COVER AND THE
ARRIVAL OF ANOTHER FRESH SUPPLY OF ARCTIC AIR INTO THE REGION LATE
THURSDAY NIGHT AND INTO FRIDAY...AS A STRONG +1040MB CANADIAN
SURFACE HIGH BUILDS OVER THE REGION...WILL SUPPORT TEMPERATURES WELL
BELOW NORMAL(15-20 DEGREES FRIDAY AND SATURDAY. DRY WITH HIGHS IN
THE MID 30S NORTH TO POSSIBLY LOWER 40S SOUTH...WITH SATURDAY BEING
THE COLDEST DAY OF THE TWO. -CBL
THE LONG-TERM SATURDAY NIGHT THROUGH WEDNESDAY IS CATEGORIZED BY
SOME UNCERTAINTY IN PRECIPITATION TIMING AND TYPE...WITH AT LEAST
MODEST CONFIDENCE IN MUCH WARMER TEMPERATURES DEVELOPING BY THE END
OF THIS PERIOD THAN WHAT HAS BEEN OCCURRING RECENTLY. DRYING IS
FORECAST FOR SATURDAY NIGHT...WITH A MID-LEVEL SHORTWAVE MOVING INTO
THE CAROLINAS BY SUNDAY NIGHT. AS HEIGHTS ALOFT RISE LATE IN THE
WEEKEND AND EARLY NEXT WEEK...THE 06Z GFS IN PARTICULAR AND POSSIBLY
EVEN THE 12Z GFS SEEMS TO HAVE ISSUES WITH FEEDBACK SUCH THAT THE
ECMWF IS PREFERRED OVERALL. IT SHOULD BE COLD TO START SUNDAY
MORNING AS CLOUDS INCREASE...BUT THE GFS AND ECMWF TREND OF A LATER
ARRIVAL OF MID-LEVEL VORTICITY AND OVERALL MOISTURE INCREASE SHOULD
RESULT IN PRECIPITATION BEING IN THE FORM OF LIQUID BY THE TIME ANY
WOULD ARRIVE LATER IN THE DAY. PARTIAL THICKNESSES AND MODEL
SOUNDINGS CURRENTLY SUPPORT THIS...AND WILL HAVE A CHANCE OF
AFTERNOON RAIN SUNDAY PRIMARILY TOWARD THE YADKIN RIVER FOLLOWED BY
CHANCES OF RAIN OVERNIGHT...WITH SURFACE TEMPERATURES REMAINING
ABOVE FREEZING AND MODEL SOUNDINGS SHOWING WARMING ALOFT AS 1000-
850MB THICKNESSES RISE AROUND 20M DURING THE NIGHT...SUGGESTING THE
POTENTIAL FOR LOW TEMPERATURES EARLY SUNDAY NIGHT FOLLOWED BY STEADY
OR A SLOW RISE IN READINGS LATE.
A BRIEF WARMUP OCCURS MONDAY AHEAD OF A COLD FRONT THAT MOVES
THROUGH CENTRAL NORTH CAROLINA LATER IN THE DAY AND AT NIGHT. STRONG
HIGH PRESSURE BUILDS IN BEHIND THE COLD FRONT...AND THE PATTERN
WOULD SUGGEST PRETTY CHILLY TEMPERATURES ONCE AGAIN WITH THE 1000-
850MB THICKNESSES SUGGESTING LOWS A LITTLE BELOW FREEZING. MOS
GUIDANCE LOWS ARE AT LEAST ONE IF NOT MORE CATEGORIES ABOVE THIS...
SO FOR NOW WILL SIMPLY UNDERCUT GUIDANCE WITH OVERNIGHT LOWS AT OR
SLIGHTLY ABOVE FREEZING. CONDITIONS SHOULD DRY BRIEFLY BEHIND THE
FRONT AS HIGH PRESSURE BUILDS IN...THEN UNCERTAINTY INCREASES AS THE
GFS AND THE ECMWF SUGGEST MOISTURE RETURNING TO CENTRAL NORTH
CAROLINA AS THE GULF OPENS BY TUESDAY INTO TUESDAY NIGHT. IF
PRECIPITATION WOULD RETURN TO CENTRAL NORTH CAROLINA QUICKLY ENOUGH
ON TUESDAY...PRECIPITATION TYPE CONCERNS WOULD EXIST DUE TO CHILLY
THICKNESSES TO START THE DAY. BY 00Z WEDNESDAY ON THE 12Z GFS...AND
FOR THE MOST PART ON THE 00Z ECMWF...THICKNESSES ARE WARM ENOUGH FOR
RAIN AND BASED ON THE WARM-AIR ADVECTION AT THE TIME WOULD
ANTICIPATE ANOTHER POTENTIAL NON-DIURNAL TEMPERATURE SCENARIO AS ANY
COLD-AIR DAMMING ERODES. BASED ON THE PATTERN WILL ONLY NOTE A
SLIGHT CHANCE OF RAIN OR SNOW EARLY ON THE SIXTH DAY IN THE WESTERN
PIEDMONT WITH A CHANCE OF JUST ALL RAIN THROUGHOUT CENTRAL NORTH
CAROLINA BY TUESDAY AFTERNOON. 1000-850MB THICKNESSES ON THE 12Z GFS
AND 00Z ECMWF ARE QUITE WARM WEDNESDAY...APPROACHING 1380M ON THE
LATEST GFS AND ONLY SLIGHTLY COOLER ON THE 00Z ECMWF...SUCH THAT...
WITH SHOWERY CONDITIONS IN A MOIST AIR MASS AND A SOUTHWEST FLOW
ALOFT...HIGH TEMPERATURES COULD POSSIBLY REACH THE 60S THROUGHOUT
CENTRAL NORTH CAROLINA WITH SOME TEMPERATURES PUSHING OR EXCEEDING
70F ESPECIALLY OVER PARTS OF THE SANDHILLS AND SOUTHERN COASTAL
PLAIN. -DJF
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AS OF 1255 PM WEDNESDAY...
FOR THE 18Z VALID TAF PERIOD...HIGH CONFIDENCE IN VFR CONDITIONS FOR
THE REST OF THIS AFTERNOON DETERIORATING QUICKLY TO IFR AND SUB-IFR
CONDITIONS THIS EVENING...CONTINUING OVERNIGHT. GUIDANCE SUGGESTS
PRECIPITATION MOVING SOUTHWEST TO NORTHEAST INTO AND ACROSS CENTRAL
NORTH CAROLINA FROM VERY LATE THIS AFTERNOON THROUGH THIS EVENING...
WITH PRECIPITATION ACROSS THE AREA BY 03Z. MODEL SOUNDINGS FROM THE
NAM AND GFS SUGGEST WHATEVER LIQUID PRECIPITATION THERE MAY BE TO
START CHANGING QUICKLY TO SNOW...WITH ENOUGH WARMING ALOFT THAT A
PRECIPITATION TYPE OF SNOW AND SLEET IS QUITE POSSIBLE AT KRDU AND
KRWI. AT KFAY...THE ABOVE FREEZING DEPTH IS A LITTLE HIGHER AND
LIGHT RAIN MAY LINGER A LITTLE LONGER AT THE START BEFORE A
TRANSITION TO SNOW...SLEET...AND FREEZING RAIN...WITH THE NAM MODEL
MOST SUGGESTIVE OF WARMTH ALOFT FOR FREEZING RAIN AND MAINLY FOR A
COUPLE OR THREE HOURS CENTERED AROUND 06Z. DRYING ALOFT VERY LATE
TONIGHT INTO THURSDAY MORNING SUGGEST PRECIPITATION CHANGING TO
FREEZING DRIZZLE OR DRIZZLE...WITH IFR CONDITIONS CONTINUING IN LOW
CLOUDS. VARIABLE WINDS THIS AFTERNOON BECOME NORTH-NORTHEAST AND
NORTHEAST THIS EVENING AS LOW PRESSURE GETS CLOSER AND MOVES
NORTHEAST ALONG THE ATLANTIC COAST.
BEYOND THE 18Z VALID TAF PERIOD...CONFIDENCE DIMINISHES IN
IMPROVEMENT FROM IFR CONDITIONS...WITH AVIATION INTERESTS BEING
PREPARED FOR THE LIKELIHOOD OF SUB-VFR CONDITIONS THROUGH THURSDAY
NIGHT ALBEIT WITH A FEW PERIODS OF VFR CONDITIONS POSSIBLE MAINLY
THURSDAY NIGHT. SUB-VFR CONDITIONS REMAIN POSSIBLE IN LOW CLOUDS
THROUGH FRIDAY WITH A GREATER LIKELIHOOD OF VFR CONDITIONS FOR
FRIDAY NIGHT. VFR CONDITIONS EXPECTED SATURDAY WITH CLOUDS
INCREASING AND LOWERING FOR SUNDAY...THEN SUB-VFR CONDITIONS LIKELY
FOR SUNDAY NIGHT INTO MONDAY ALONG WITH CHANCES FOR PRECIPITATION.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL NOON WEDNESDAY FOR NCZ007>011-024>028-
040>043-076>078-085-086-088-089.
WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO NOON EST THURSDAY
FOR NCZ078-085-086-088-089.
WINTER STORM WARNING FROM 6 PM THIS EVENING TO NOON EST THURSDAY FOR
NCZ007>011-021>028-038>043-073>077-083-084.
&&
$$
SYNOPSIS...RAH
NEAR TERM...BLAES
SHORT TERM...BLAES/RAH
LONG TERM...CBL/DJF
AVIATION...DJF
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1200 PM EST WED FEB 25 2015
.SYNOPSIS...AN AREA OF LOW PRESSURE WILL FORM OVER THE NORTHERN GULF
OF MEXICO TODAY AND WILL THEN TRACK QUICKLY NORTHEAST...OFF THE
CAROLINA COAST OVERNIGHT THROUGH EARLY THURSDAY. COLD CANADIAN
HIGH PRESSURE WILL THEN BUILD INTO THE REGION FRIDAY AND INTO THE
WEEKEND.
&&
.NEAR TERM /TODAY/...
AS OF 1105 AM WEDNESDAY...
...WINTER WEATHER ADVISORY FOR BLACK ICE THROUGH NOON TODAY...
WILL CANCEL THE WINTER WEATHER ADVISORY SHORTLY.
MORNING UPPER AIR ANALYSIS SHOWS THE SHEARING SHORT WAVE
TROUGH OVER TEXAS THIS MORNING WITH SHORT WAVE RIDGING OUT AHEAD OF
IT ACROSS THE SOUTHEAST. HIGH CLOUDS HAVE BEEN ADVANCING NORTHEAST
AHEAD OF THE SYSTEM AND MOST OF CENTRAL NC IS ALREADY UNDER AT LEAST
A THIN VEIL OF CIRRUS. REGIONAL RADAR IMAGERY SHOWS PRECIPITATION
EXPANDING ACROSS THE DEEP SOUTH WITH MEASURABLE PRECIP NOW REPORTED
ACROSS CENTRAL ALABAMA. NO PRECIPITATION IS EXPECTED IN CENTRAL NC
DURING THE TODAY PERIOD BUT TODAYS WEATHER COULD STILL PLAY A ROLE IN
THE IMPACT OF TONIGHTS WINTER STORM. THE TEMPERATURES FORECAST FOR
TODAY IS PROBLEMATIC AS YESTERDAYS SNOWFALL WILL DAMPEN THE
TEMPERATURE RECOVERY THIS AFTERNOON AND ENERGY IS DIVERTED INTO
MELTING AND EVAPORATING SNOW AND MELT WATER. EVEN SO...SOME
GUIDANCE INCLUDING THE HRRR SUGGEST HIGHS IN THE MID 40S TO AROUND
50. NOT READY TO JUMP THAT HIGH BUT CURRENT TEMP AT OUR OFFICE IS 37
AT 1045 AND HAVE MADE A SLIGHT UPWARD ADJUSTMENT IN TEMPERATURES FOR
TODAY. THIS UPWARD TREND IN BOUNDARY LAYER TEMPERATURES WOULD
DELAY THE CHANGEOVER FROM RAIN OR MIXED RAIN AND SNOW THIS EVENING
TO SNOW AND POTENTIALLY LIMIT ACCUMULATIONS A BIT...PRIMARILY
ACROSS THE FAR SOUTHERN TIER IN THE SANDHILLS AND SOUTHERN COASTAL
PLAIN. -BLAES
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY/...
AS OF 1100 AM WEDNESDAY...
*** QUICK 1100 AM UPDATE. QUICK LOOK AT 12Z GUIDANCE NOTES NO
IMMEDIATE OR SIGNIFICANT FORECAST ADJUSTMENTS ARE NEEDED BUT NAM
CONTINUES TO TREND NORTH A BIT AND WITH THE GFS SHOWING A SLIGHT
NORTHWARD ADJUSTMENT.
...WINTER STORM WARNING HAS BEEN ISSUED FOR TONIGHT AND THURSDAY FOR
ALL THE PIEDMONT...NORTHERN/CENTRAL COASTAL PLAIN AND SANDHILLS...
...WINTER WEATHER ADVISORY HAS BEEN ISSUED FOR TONIGHT AND THURSDAY
FOR THE SOUTHERN COASTAL PLAIN...
THERE HAS BEEN A CONTINUED SLIGHT NORTHWARD SHIFT IN GUIDANCE SINCE
YESTERDAY...WHICH EQUATES TO A WETTER AND MARGINALLY WARMER SOLUTION
FOR CENTRAL NC...THOUGH THE OVERALL PATTERN REMAINS UNCHANGED WITH
THE DEAMPLIFICATION/ENE SHEARING OF A SHORTWAVE TROUGH FROM NEAR THE
RIO GRANDE THIS MORNING TO THE MIDDLE ATLANTIC COAST BY THU MORNING.
THE ASSOCIATED FORCING FOR ASCENT ATOP A PAIR OF CLOSELY-SPACED AND
STRONG FRONTAL ZONES DRAPED ACROSS THE NORTHERN GOM TO A SFC LOW
ABOUT MIDWAY BETWEEN CAPE HATTERAS AND BERMUDA...WILL RESULT IN THE
CONTINUED DEEPENING OF A SFC LOW OVER THE NW GOM THIS MORNING.
GUIDANCE IS THEN FAIRLY TIGHTLY CLUSTERED WITH THE TRACK OF A MILLER
"A" SFC LOW ACROSS THE NORTHERN FL PENINSULA THIS EVENING AND
ROUGHLY ALONG THE GULF STREAM TO JUST EAST OF CAPE HATTERAS BY 12Z
THU.
AS HAS BEEN NOTED IN PREVIOUS DISCUSSIONS...THE LACK OF A PARENT
COLD HIGH IS ADMITTEDLY SOMEWHAT CONCERNING. AN ARCTIC SFC HIGH AT
1045 MB WILL BE CENTERED OVER SOUTHERN ALBERTA/SASKATCHEWAN AND WILL
CONSEQUENTLY HAVE LITTLE INFLUENCE AT OUR LATITUDE DURING THE HEIGHT
OF THE STORM TONIGHT. HOWEVER...A VERY FAVORABLE MILLER "A" CYCLONE
TRACK ALONG AND JUST OFFSHORE THE SE COAST...IN CONJUNCTION WITH A
PRECEDING ARCTIC HIGH THAT APPEARS TO BE JUST COLD ENOUGH DESPITE
BEING IN A DRAMATICALLY WEAKENED STATE FROM A COUPLE OF DAYS
AGO...BUT IS STILL CHARACTERIZED BY SFC TEMPERATURES AND DEWPOINTS
MOSTLY IN THE TEENS TO 20S OVER NC THIS MORNING...WILL SUPPORT A
SIGNIFICANT WINTER STORM **WITH A NARROW P-TYPE (SNOW/RAIN)
TRANSITION ZONE AND DEEP NEAR FREEZING ISOTHERMAL PROFILES
CHARACTERISTIC OF MILLER "A` SFC PATTERNS.** PRECIPITATION
RATES...OCCASIONALLY MODERATE TO HEAVY...WILL ONLY SERVE TO ENHANCE
THE DEEP NEAR FREEZING ISOTHERMAL PROFILES RIGHT ALONG THE SNOW/COLD
RAIN INTERFACE...OWING TO MELTING. A LITTLE MIX OF SLEET AND
FREEZING RAIN ARE HARD TO AVOID IN CENTRAL NC WINTER STORMS...AND IN
MILLER "A" STORMS INCLUDING THIS ONE...SUCH OCCURRENCE IS MOST LIKELY
NEAR THE NARROW TRANSITION SNOW/RAIN ZONE. NO APPRECIABLE ICING IS
ANTICIPATED...HOWEVER...IN PART SINCE SURFACE TEMPERATURES ARE
EXPECTED TO HOLD NEARLY STEADY IN THE 29 TO 33 DEGREE RANGE OVER THE
WARNING AREA...AND 32 TO 34 DEGREES OVER THE ADVISORY AREA WHERE
SUCH ICING OCCURRENCE WOULD BE MOST PROBABLE.
DESPITE SOME MINIMAL OVERALL RISE IN THICKNESS VALUES VERSUS THE
SLIGHTLY COLDER AND DRIER SOLUTIONS OF YESTERDAY...PROJECTED PARTIAL
THICKNESS VALUES OVER MOST OF THE PIEDMONT AND NORTHERN COASTAL
PLAIN REMAIN SQUARELY IN THE RANGE TYPICAL OF SIGNIFICANT SNOWSTORMS
IN CENTRAL NC. WITH A SLIGHTLY MILDER SOLUTION COMES A SLIGHTLY
WETTER ONE...LED BY A BLEND OF THE VERY SIMILAR 00Z ECMWF AND
GFS...SO QPF HAS BEEN RAISED TO AROUND ONE HALF INCH OVER THE NW
PIEDMONT TO AS MUCH AS ONE INCH OVER THE SOUTHERN COASTAL PLAIN.
PARTIAL THICKNESS VALUES HEAVILY WEIGHTED TOWARD THE FAVORED 00Z
ECMWF AND GFS...FAVORS MOSTLY SNOW OVER THE PIEDMONT AND NORTHERN
COASTAL PLAIN...WITH A MIX OF SNOW AND A COLD RAIN (OR FREEZING RAIN
WITH LITTLE ACCRUAL WHERE SFC TEMPERATURES OSCILLATE ABOUT THE
FREEZING MARK) OVER THE ADVISORY AREA.
SNOW RATIOS BETWEEN 00-06Z THU OF 10-14:1 PER WPC WWD SLR GUIDANCE
AND SUPPORTED BY THERMAL PROFILES THAT RANGE FROM DEEP NEAR FREEZING
ISOTHERMAL IN THER NARROW TRANSITION ZONE TO WELL BELOW FREEZING...
EXCEPT RIGHT AT THE SURFACE...ALONG AND NORTH OF THE I-40/I-85
CORRIDOR...ARE EXPECTED TO DECREASE PARTICULARLY NEAR NARROW
TRANSITION ZONE TO CLOSER TO 8-10:1 PER WHAT IS TYPICAL OF EVENTS
CHARACTERIZED BY PARTIAL THICKNESS VALUES IN THE ~1285/~1535 METER
RANGE. SLIGHTLY LOWER RATIOS...CLOSER TO 4-6:1 WITHIN THE SNOW/RAIN
TRANSITION ZONE - OR ROUGHLY ALONG THE BOUNDARY OF WINTER STORM
WARNING AND WINTER WEATHER ADVISORY - WHERE THE MIXING WITH A COLD
RAIN WILL RESULT IN A MORE SLUSHY ACCUMULATION VERSUS POINTS
NORTHWARD.
BASED ON THESE RATIOS...AND THE QPF NOTED ABOVE...WIDESPREAD
SNOWFALL ACCUMULATIONS OF 3 TO 6 INCHES ARE LIKELY OVER THE WARNING
AREA...WITH A STRIPE OF 6 TO 8 INCHES ROUGHLY INVOF OR JUST NORTH OF
THE US HIGHWAY 64 CORRIDOR...WITH LOCALLY HIGHER AMOUNTS FROM THE
TRIANGLE TO ROANOKE RAPIDS AND ROCKY MOUNT. MEANWHILE...LESSER
TOTALS OF 1 TO 3 INCHES ARE EXPECTED OVER THE ADVISORY AREA...WHERE
AGAIN...PARTIAL THICKNESS AND SFC TEMPERATURE VALUES MARGINALLY
ABOVE FREEZING WILL SUPPORT A MIXING WITH OR CHANGEOVER TO A COLD
RAIN BETWEEN MIDNIGHT AND 5 AM. EVEN THERE...HOWEVER...THE NORTHERN
PORTIONS OF THE ADVISORY COUNTIES MAY EXCEED WARNING CRITERIA OF 3
INCHES.
THE APPROACH OF A WEAK CLIPPER LOW AND ATTENDING SHORTWAVE TROUGH
WILL CAUSE THE LINGERING STRATUS LAYER AND ASSOCIATED MOSTLY CLOUDY
SKIES TO PRODUCE OCCASIONAL DRIZZLE OR FREEZING DRIZZLE...AFTER
LINGERING LIGHT SNOW...OWING TO A LOSS OF SATURATION ALOFT/IN THE
ICE NUCLEATION ZONE - BUT WITH MINIMAL ADDITIONAL IMPACT. CHILLY
TEMPERATURES IN THE LOWER TO MIDDLE 30S.
&&
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
AS OF 1200 PM WEDNESDAY...
SHORTWAVE DISTURBANCES EMBEDDED IN THE CONTINUED SWLY FLOW ALOFT AND
LINGERING LOW-LEVEL MOISTURE OWING TO WHAT WILL LIKELY BE A MOIST
SNOW COVER GROUND(AT LEAST FOR THE NORTHERN TWO-THIRDS OF THE
FORECAST AREA)...WILL RESULT IN RATHER EXTENSIVE CLOUDINESS INTO
SATURDAY. COMBINATION OF THIS CLOUD COVER...SNOW COVER AND THE
ARRIVAL OF ANOTHER FRESH SUPPLY OF ARCTIC AIR INTO THE REGION LATE
THURSDAY NIGHT AND INTO FRIDAY...AS A STRONG +1040MB CANADIAN
SURFACE HIGH BUILDS OVER THE REGION...WILL SUPPORT TEMPERATURES WELL
BELOW NORMAL(15-20 DEGREES FRIDAY AND SATURDAY. DRY WITH HIGHS IN
THE MID 30S NORTH TO POSSIBLY LOWER 40S SOUTH...WITH SATURDAY BEING
THE COLDEST DAY OF THE TWO. -CBL
THE LONG-TERM SATURDAY NIGHT THROUGH WEDNESDAY IS CATEGORIZED BY
SOME UNCERTAINTY IN PRECIPITATION TIMING AND TYPE...WITH AT LEAST
MODEST CONFIDENCE IN MUCH WARMER TEMPERATURES DEVELOPING BY THE END
OF THIS PERIOD THAN WHAT HAS BEEN OCCURRING RECENTLY. DRYING IS
FORECAST FOR SATURDAY NIGHT...WITH A MID-LEVEL SHORTWAVE MOVING INTO
THE CAROLINAS BY SUNDAY NIGHT. AS HEIGHTS ALOFT RISE LATE IN THE
WEEKEND AND EARLY NEXT WEEK...THE 06Z GFS IN PARTICULAR AND POSSIBLY
EVEN THE 12Z GFS SEEMS TO HAVE ISSUES WITH FEEDBACK SUCH THAT THE
ECMWF IS PREFERRED OVERALL. IT SHOULD BE COLD TO START SUNDAY
MORNING AS CLOUDS INCREASE...BUT THE GFS AND ECMWF TREND OF A LATER
ARRIVAL OF MID-LEVEL VORTICITY AND OVERALL MOISTURE INCREASE SHOULD
RESULT IN PRECIPITATION BEING IN THE FORM OF LIQUID BY THE TIME ANY
WOULD ARRIVE LATER IN THE DAY. PARTIAL THICKNESSES AND MODEL
SOUNDINGS CURRENTLY SUPPORT THIS...AND WILL HAVE A CHANCE OF
AFTERNOON RAIN SUNDAY PRIMARILY TOWARD THE YADKIN RIVER FOLLOWED BY
CHANCES OF RAIN OVERNIGHT...WITH SURFACE TEMPERATURES REMAINING
ABOVE FREEZING AND MODEL SOUNDINGS SHOWING WARMING ALOFT AS 1000-
850MB THICKNESSES RISE AROUND 20M DURING THE NIGHT...SUGGESTING THE
POTENTIAL FOR LOW TEMPERATURES EARLY SUNDAY NIGHT FOLLOWED BY STEADY
OR A SLOW RISE IN READINGS LATE.
A BRIEF WARMUP OCCURS MONDAY AHEAD OF A COLD FRONT THAT MOVES
THROUGH CENTRAL NORTH CAROLINA LATER IN THE DAY AND AT NIGHT. STRONG
HIGH PRESSURE BUILDS IN BEHIND THE COLD FRONT...AND THE PATTERN
WOULD SUGGEST PRETTY CHILLY TEMPERATURES ONCE AGAIN WITH THE 1000-
850MB THICKNESSES SUGGESTING LOWS A LITTLE BELOW FREEZING. MOS
GUIDANCE LOWS ARE AT LEAST ONE IF NOT MORE CATEGORIES ABOVE THIS...
SO FOR NOW WILL SIMPLY UNDERCUT GUIDANCE WITH OVERNIGHT LOWS AT OR
SLIGHTLY ABOVE FREEZING. CONDITIONS SHOULD DRY BRIEFLY BEHIND THE
FRONT AS HIGH PRESSURE BUILDS IN...THEN UNCERTAINTY INCREASES AS THE
GFS AND THE ECMWF SUGGEST MOISTURE RETURNING TO CENTRAL NORTH
CAROLINA AS THE GULF OPENS BY TUESDAY INTO TUESDAY NIGHT. IF
PRECIPITATION WOULD RETURN TO CENTRAL NORTH CAROLINA QUICKLY ENOUGH
ON TUESDAY...PRECIPITATION TYPE CONCERNS WOULD EXIST DUE TO CHILLY
THICKNESSES TO START THE DAY. BY 00Z WEDNESDAY ON THE 12Z GFS...AND
FOR THE MOST PART ON THE 00Z ECMWF...THICKNESSES ARE WARM ENOUGH FOR
RAIN AND BASED ON THE WARM-AIR ADVECTION AT THE TIME WOULD
ANTICIPATE ANOTHER POTENTIAL NON-DIURNAL TEMPERATURE SCENARIO AS ANY
COLD-AIR DAMMING ERODES. BASED ON THE PATTERN WILL ONLY NOTE A
SLIGHT CHANCE OF RAIN OR SNOW EARLY ON THE SIXTH DAY IN THE WESTERN
PIEDMONT WITH A CHANCE OF JUST ALL RAIN THROUGHOUT CENTRAL NORTH
CAROLINA BY TUESDAY AFTERNOON. 1000-850MB THICKNESSES ON THE 12Z GFS
AND 00Z ECMWF ARE QUITE WARM WEDNESDAY...APPROACHING 1380M ON THE
LATEST GFS AND ONLY SLIGHTLY COOLER ON THE 00Z ECMWF...SUCH THAT...
WITH SHOWERY CONDITIONS IN A MOIST AIR MASS AND A SOUTHWEST FLOW
ALOFT...HIGH TEMPERATURES COULD POSSIBLY REACH THE 60S THROUGHOUT
CENTRAL NORTH CAROLINA WITH SOME TEMPERATURES PUSHING OR EXCEEDING
70F ESPECIALLY OVER PARTS OF THE SANDHILLS AND SOUTHERN COASTAL
PLAIN. -DJF
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
AS OF 642 AM WEDNESDAY...
24-HR TAF PERIOD: IFR STRATUS DECK HAS STEADILY SHIFTED SOUTHEASTWARD
OVER THE PAST HOURS AS WEAK SURFACE HIGH BUILDS INTO THE AREA FROM
THE NORTHWEST. SOUNDINGS INDICATE THAT THIS SHRINKING AREA OF LOW
CLOUDS SHOULD MIX OUT RATHER QUICKLY...AOA 14Z WITH VFR CONDITIONS
EXPECTED UNDERNEATH A THICKENING CIRRUS SHIELD.
CONDITIONS WILL DETERIORATE RAPIDLY BETWEEN 00Z TO 03Z AS A LOW
PRESSURE SYSTEM TRACKS FROM THE NORTHERN GULF OF MEXICO TO OFF THE
CAROLINA COAST OVERNIGHT THROUGH EARLY THURSDAY MORNING...SPREADING
WINTRY PRECIP INTO THE AREA. MODERATE TO HEAVY SNOW WILL OVERSPREAD
ALL OF THE TERMINALS IN THE 00Z-03Z TIME FRAME....POSSIBLY MIXING
WITH RAIN AT KFAY. PRECIP WILL GRADUALLY TAPER OFF BETWEEN 12 TO
15Z THU...ENDING AS FREEZING RAIN/DRIZZLE.
LOOKING AHEAD: SUB-VFR CEILINGS WILL LIKELY PERSIST IN THE WAKE OF
THE COASTAL LOW PRESSURE SYSTEM DURING THE DAY THU. VFR CONDITIONS
MAY RETURN FOR A PERIOD ON FRI...THOUGH INTERMITTENT SUB-VFR
CONDITIONS WILL BE POSSIBLE FRI INTO THE WEEKEND IN ASSOC/W THE
UNSETTLED PROGRESSIVE SYNOPTIC PATTERN IN PLACE.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL NOON WEDNESDAY FOR NCZ007>011-024>028-
040>043-076>078-085-086-088-089.
WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO NOON EST THURSDAY
FOR NCZ078-085-086-088-089.
WINTER STORM WARNING FROM 6 PM THIS EVENING TO NOON EST THURSDAY FOR
NCZ007>011-021>028-038>043-073>077-083-084.
&&
$$
SYNOPSIS...CBL
NEAR TERM...BLAES
SHORT TERM...BLAES/RAH
LONG TERM...CBL/DJF
AVIATION...CBL/BSD/VINCENT
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1105 AM EST WED FEB 25 2015
.SYNOPSIS...AN AREA OF LOW PRESSURE WILL FORM OVER THE NORTHERN GULF
OF MEXICO TODAY AND WILL THEN TRACK QUICKLY NORTHEAST...OFF THE
CAROLINA COAST OVERNIGHT THROUGH EARLY THURSDAY. COLD CANADIAN
HIGH PRESSURE WILL THEN BUILD INTO THE REGION FRIDAY AND INTO THE
WEEKEND.
&&
.NEAR TERM /TODAY/...
AS OF 1105 AM WEDNESDAY...
...WINTER WEATHER ADVISORY FOR BLACK ICE THROUGH NOON TODAY...
WILL CANCEL THE WINTER WEATHER ADVISORY SHORTLY.
MORNING UPPER AIR ANALYSIS SHOWS THE SHEARING SHORT WAVE
TROUGH OVER TEXAS THIS MORNING WITH SHORT WAVE RIDGING OUT AHEAD OF
IT ACROSS THE SOUTHEAST. HIGH CLOUDS HAVE BEEN ADVANCING NORTHEAST
AHEAD OF THE SYSTEM AND MOST OF CENTRAL NC IS ALREADY UNDER AT LEAST
A THIN VEIL OF CIRRUS. REGIONAL RADAR IMAGERY SHOWS PRECIPITATION
EXPANDING ACROSS THE DEEP SOUTH WITH MEASURABLE PRECIP NOW REPORTED
ACROSS CENTRAL ALABAMA. NO PRECIPITATION IS EXPECTED IN CENTRAL NC
DURING THE TODAY PERIOD BUT TODAYS WEATHER COULD STILL PLAY A ROLE IN
THE IMPACT OF TONIGHTS WINTER STORM. THE TEMPERATURES FORECAST FOR
TODAY IS PROBLEMATIC AS YESTERDAYS SNOWFALL WILL DAMPEN THE
TEMPERATURE RECOVERY THIS AFTERNOON AND ENERGY IS DIVERTED INTO
MELTING AND EVAPORATING SNOW AND MELT WATER. EVEN SO...SOME
GUIDANCE INCLUDING THE HRRR SUGGEST HIGHS IN THE MID 40S TO AROUND
50. NOT READY TO JUMP THAT HIGH BUT CURRENT TEMP AT OUR OFFICE IS 37
AT 1045 AND HAVE MADE A SLIGHT UPWARD ADJUSTMENT IN TEMPERATURES FOR
TODAY. THIS UPWARD TREND IN BOUNDARY LAYER TEMPERATURES WOULD
DELAY THE CHANGEOVER FROM RAIN OR MIXED RAIN AND SNOW THIS EVENING
TO SNOW AND POTENTIALLY LIMIT ACCUMULATIONS A BIT...PRIMARILY
ACROSS THE FAR SOUTHERN TIER IN THE SANDHILLS AND SOUTHERN COASTAL
PLAIN. -BLAES
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY/...
AS OF 1100 AM WEDNESDAY...
*** QUICK 1100 AM UPDATE. QUICK LOOK AT 12Z GUIDANCE NOTES NO
IMMEDIATE OR SIGNIFICANT FORECAST ADJUSTMENTS ARE NEEDED BUT NAM
CONTINUES TO TREND NORTH A BIT AND WITH THE GFS SHOWING A SLIGHT
NORTHWARD ADJUSTMENT.
...WINTER STORM WARNING HAS BEEN ISSUED FOR TONIGHT AND THURSDAY FOR
ALL THE PIEDMONT...NORTHERN/CENTRAL COASTAL PLAIN AND SANDHILLS...
...WINTER WEATHER ADVISORY HAS BEEN ISSUED FOR TONIGHT AND THURSDAY
FOR THE SOUTHERN COASTAL PLAIN...
THERE HAS BEEN A CONTINUED SLIGHT NORTHWARD SHIFT IN GUIDANCE SINCE
YESTERDAY...WHICH EQUATES TO A WETTER AND MARGINALLY WARMER SOLUTION
FOR CENTRAL NC...THOUGH THE OVERALL PATTERN REMAINS UNCHANGED WITH
THE DEAMPLIFICATION/ENE SHEARING OF A SHORTWAVE TROUGH FROM NEAR THE
RIO GRANDE THIS MORNING TO THE MIDDLE ATLANTIC COAST BY THU MORNING.
THE ASSOCIATED FORCING FOR ASCENT ATOP A PAIR OF CLOSELY-SPACED AND
STRONG FRONTAL ZONES DRAPED ACROSS THE NORTHERN GOM TO A SFC LOW
ABOUT MIDWAY BETWEEN CAPE HATTERAS AND BERMUDA...WILL RESULT IN THE
CONTINUED DEEPENING OF A SFC LOW OVER THE NW GOM THIS MORNING.
GUIDANCE IS THEN FAIRLY TIGHTLY CLUSTERED WITH THE TRACK OF A MILLER
"A" SFC LOW ACROSS THE NORTHERN FL PENINSULA THIS EVENING AND
ROUGHLY ALONG THE GULF STREAM TO JUST EAST OF CAPE HATTERAS BY 12Z
THU.
AS HAS BEEN NOTED IN PREVIOUS DISCUSSIONS...THE LACK OF A PARENT
COLD HIGH IS ADMITTEDLY SOMEWHAT CONCERNING. AN ARCTIC SFC HIGH AT
1045 MB WILL BE CENTERED OVER SOUTHERN ALBERTA/SASKATCHEWAN AND WILL
CONSEQUENTLY HAVE LITTLE INFLUENCE AT OUR LATITUDE DURING THE HEIGHT
OF THE STORM TONIGHT. HOWEVER...A VERY FAVORABLE MILLER "A" CYCLONE
TRACK ALONG AND JUST OFFSHORE THE SE COAST...IN CONJUNCTION WITH A
PRECEDING ARCTIC HIGH THAT APPEARS TO BE JUST COLD ENOUGH DESPITE
BEING IN A DRAMATICALLY WEAKENED STATE FROM A COUPLE OF DAYS
AGO...BUT IS STILL CHARACTERIZED BY SFC TEMPERATURES AND DEWPOINTS
MOSTLY IN THE TEENS TO 20S OVER NC THIS MORNING...WILL SUPPORT A
SIGNIFICANT WINTER STORM **WITH A NARROW P-TYPE (SNOW/RAIN)
TRANSITION ZONE AND DEEP NEAR FREEZING ISOTHERMAL PROFILES
CHARACTERISTIC OF MILLER "A` SFC PATTERNS.** PRECIPITATION
RATES...OCCASIONALLY MODERATE TO HEAVY...WILL ONLY SERVE TO ENHANCE
THE DEEP NEAR FREEZING ISOTHERMAL PROFILES RIGHT ALONG THE SNOW/COLD
RAIN INTERFACE...OWING TO MELTING. A LITTLE MIX OF SLEET AND
FREEZING RAIN ARE HARD TO AVOID IN CENTRAL NC WINTER STORMS...AND IN
MILLER "A" STORMS INCLUDING THIS ONE...SUCH OCCURRENCE IS MOST LIKELY
NEAR THE NARROW TRANSITION SNOW/RAIN ZONE. NO APPRECIABLE ICING IS
ANTICIPATED...HOWEVER...IN PART SINCE SURFACE TEMPERATURES ARE
EXPECTED TO HOLD NEARLY STEADY IN THE 29 TO 33 DEGREE RANGE OVER THE
WARNING AREA...AND 32 TO 34 DEGREES OVER THE ADVISORY AREA WHERE
SUCH ICING OCCURRENCE WOULD BE MOST PROBABLE.
DESPITE SOME MINIMAL OVERALL RISE IN THICKNESS VALUES VERSUS THE
SLIGHTLY COLDER AND DRIER SOLUTIONS OF YESTERDAY...PROJECTED PARTIAL
THICKNESS VALUES OVER MOST OF THE PIEDMONT AND NORTHERN COASTAL
PLAIN REMAIN SQUARELY IN THE RANGE TYPICAL OF SIGNIFICANT SNOWSTORMS
IN CENTRAL NC. WITH A SLIGHTLY MILDER SOLUTION COMES A SLIGHTLY
WETTER ONE...LED BY A BLEND OF THE VERY SIMILAR 00Z ECMWF AND
GFS...SO QPF HAS BEEN RAISED TO AROUND ONE HALF INCH OVER THE NW
PIEDMONT TO AS MUCH AS ONE INCH OVER THE SOUTHERN COASTAL PLAIN.
PARTIAL THICKNESS VALUES HEAVILY WEIGHTED TOWARD THE FAVORED 00Z
ECMWF AND GFS...FAVORS MOSTLY SNOW OVER THE PIEDMONT AND NORTHERN
COASTAL PLAIN...WITH A MIX OF SNOW AND A COLD RAIN (OR FREEZING RAIN
WITH LITTLE ACCRUAL WHERE SFC TEMPERATURES OSCILLATE ABOUT THE
FREEZING MARK) OVER THE ADVISORY AREA.
SNOW RATIOS BETWEEN 00-06Z THU OF 10-14:1 PER WPC WWD SLR GUIDANCE
AND SUPPORTED BY THERMAL PROFILES THAT RANGE FROM DEEP NEAR FREEZING
ISOTHERMAL IN THER NARROW TRANSITION ZONE TO WELL BELOW FREEZING...
EXCEPT RIGHT AT THE SURFACE...ALONG AND NORTH OF THE I-40/I-85
CORRIDOR...ARE EXPECTED TO DECREASE PARTICULARLY NEAR NARROW
TRANSITION ZONE TO CLOSER TO 8-10:1 PER WHAT IS TYPICAL OF EVENTS
CHARACTERIZED BY PARTIAL THICKNESS VALUES IN THE ~1285/~1535 METER
RANGE. SLIGHTLY LOWER RATIOS...CLOSER TO 4-6:1 WITHIN THE SNOW/RAIN
TRANSITION ZONE - OR ROUGHLY ALONG THE BOUNDARY OF WINTER STORM
WARNING AND WINTER WEATHER ADVISORY - WHERE THE MIXING WITH A COLD
RAIN WILL RESULT IN A MORE SLUSHY ACCUMULATION VERSUS POINTS
NORTHWARD.
BASED ON THESE RATIOS...AND THE QPF NOTED ABOVE...WIDESPREAD
SNOWFALL ACCUMULATIONS OF 3 TO 6 INCHES ARE LIKELY OVER THE WARNING
AREA...WITH A STRIPE OF 6 TO 8 INCHES ROUGHLY INVOF OR JUST NORTH OF
THE US HIGHWAY 64 CORRIDOR...WITH LOCALLY HIGHER AMOUNTS FROM THE
TRIANGLE TO ROANOKE RAPIDS AND ROCKY MOUNT. MEANWHILE...LESSER
TOTALS OF 1 TO 3 INCHES ARE EXPECTED OVER THE ADVISORY AREA...WHERE
AGAIN...PARTIAL THICKNESS AND SFC TEMPERATURE VALUES MARGINALLY
ABOVE FREEZING WILL SUPPORT A MIXING WITH OR CHANGEOVER TO A COLD
RAIN BETWEEN MIDNIGHT AND 5 AM. EVEN THERE...HOWEVER...THE NORTHERN
PORTIONS OF THE ADVISORY COUNTIES MAY EXCEED WARNING CRITERIA OF 3
INCHES.
THE APPROACH OF A WEAK CLIPPER LOW AND ATTENDING SHORTWAVE TROUGH
WILL CAUSE THE LINGERING STRATUS LAYER AND ASSOCIATED MOSTLY CLOUDY
SKIES TO PRODUCE OCCASIONAL DRIZZLE OR FREEZING DRIZZLE...AFTER
LINGERING LIGHT SNOW...OWING TO A LOSS OF SATURATION ALOFT/IN THE
ICE NUCLEATION ZONE - BUT WITH MINIMAL ADDITIONAL IMPACT. CHILLY
TEMPERATURES IN THE LOWER TO MIDDLE 30S.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
AS OF 340 AM WEDNESDAY...
SHORTWAVE DISTURBANCES EMBEDDED IN THE CONTINUED SWLY FLOW ALOFT AND
LINGERING LOW-LEVEL MOISTURE OWING TO WHAT WILL LIKELY BE A MOIST
SNOW COVER GROUND(AT LEAST FOR THE NORTHERN TWO-THIRDS OF THE
FORECAST AREA)...WILL RESULT IN RATHER EXTENSIVE CLOUDINESS INTO
SATURDAY. COMBINATION OF THIS CLOUD COVER...SNOW COVER AND THE
ARRIVAL OF ANOTHER FRESH SUPPLY OF ARCTIC AIR INTO THE REGION LATE
THURSDAY NIGHT AND INTO FRIDAY...AS A STRONG +1040MB CANADIAN
SURFACE HIGH BUILDS OVER THE REGION...WILL SUPPORT TEMPERATURES WELL
BELOW NORMAL(15-20 DEGREES FRIDAY AND SATURDAY. DRY WITH HIGHS IN
THE MID 30S NORTH TO POSSIBLY LOWER 40S SOUTH...WITH SATURDAY BEING
THE COLDEST DAY OF THE TWO. LOWS IN THE 20S...WITH SOME TEENS
SATURDAY NIGHT.
FLOW ALOFT FLATTENS OUT TO ZONAL BY SUNDAY WHILE MODERATING CANADIAN
HIGH STARTS TO SHIFT OFF THE MID-ATLANTIC COAST AS A SW-NE ORIENTED
FRONTAL ZONE STRETCHING FROM THE SOUTHERN PLAINS INTO THE OHIO
VALLEY MOVES SLOWLY EASTWARD. MODELS HAVE SLOWED DOWN THE ONSET OF
WAA/SOUTHERLY RETURN FLOW AND RESULTANT PRECIP INTO THE AREA LATE
SUNDAY AFTERNOON/EVENING...BY WHICH TIME AIRMASS LOOKS TO HAVE
MODERATED ENOUGH TO SUPPORT ALL RAIN. IT THEN LOOKS LIKE A WET
PERIOD SUNDAY NIGHT THROUGH EARLY NEXT WEEK AS THE AFOREMENTIONED
FRONT SETTLES SOUTHWARD INTO AREA...EVENTUALLY RETURNING NORTHWARD
AS A WARM FRONT WITH CAD IMPLICATIONS TUESDAY/TUESDAY NIGHT AS HIGH
PRESSURE OVER THE GREAT LAKES/NEW ENGLANDS NOSES SOUTH INTO THE
AREA. PARTIAL THICKNESSES CURRENTLY SUGGEST ALL RAIN FOR NOW...BUT
WILL CONTINUE TO MONITOR.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
AS OF 642 AM WEDNESDAY...
24-HR TAF PERIOD: IFR STRATUS DECK HAS STEADILY SHIFTED SOUTHEASTWARD
OVER THE PAST HOURS AS WEAK SURFACE HIGH BUILDS INTO THE AREA FROM
THE NORTHWEST. SOUNDINGS INDICATE THAT THIS SHRINKING AREA OF LOW
CLOUDS SHOULD MIX OUT RATHER QUICKLY...AOA 14Z WITH VFR CONDITIONS
EXPECTED UNDERNEATH A THICKENING CIRRUS SHIELD.
CONDITIONS WILL DETERIORATE RAPIDLY BETWEEN 00Z TO 03Z AS A LOW
PRESSURE SYSTEM TRACKS FROM THE NORTHERN GULF OF MEXICO TO OFF THE
CAROLINA COAST OVERNIGHT THROUGH EARLY THURSDAY MORNING...SPREADING
WINTRY PRECIP INTO THE AREA. MODERATE TO HEAVY SNOW WILL OVERSPREAD
ALL OF THE TERMINALS IN THE 00Z-03Z TIME FRAME....POSSIBLY MIXING
WITH RAIN AT KFAY. PRECIP WILL GRADUALLY TAPER OFF BETWEEN 12 TO
15Z THU...ENDING AS FREEZING RAIN/DRIZZLE.
LOOKING AHEAD: SUB-VFR CEILINGS WILL LIKELY PERSIST IN THE WAKE OF
THE COASTAL LOW PRESSURE SYSTEM DURING THE DAY THU. VFR CONDITIONS
MAY RETURN FOR A PERIOD ON FRI...THOUGH INTERMITTENT SUB-VFR
CONDITIONS WILL BE POSSIBLE FRI INTO THE WEEKEND IN ASSOC/W THE
UNSETTLED PROGRESSIVE SYNOPTIC PATTERN IN PLACE.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL NOON WEDNESDAY FOR NCZ007>011-024>028-
040>043-076>078-085-086-088-089.
WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO NOON EST THURSDAY
FOR NCZ078-085-086-088-089.
WINTER STORM WARNING FROM 6 PM THIS EVENING TO NOON EST THURSDAY FOR
NCZ007>011-021>028-038>043-073>077-083-084.
&&
$$
SYNOPSIS...CBL
NEAR TERM...BLAES
SHORT TERM...BLAES/RAH
LONG TERM...CBL
AVIATION...CBL/BSD/VINCENT
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
409 AM EST WED FEB 25 2015
.SYNOPSIS...
A STRENGTHENING LOW PRESSURE SYSTEM WILL MOVE OUT OF THE GULF OF
MEXICO TODAY...AND OFF THE SOUTH CAROLINA COAST TONIGHT. THIS WILL
BRING PERIODS OF RAIN TO THE AREA TONIGHT...WITH SOME SNOW
POSSIBLE WELL INLAND. THIS LOW PRESSURE WILL PULL AWAY ON
THURSDAY...LEAVING SOME LIGHT DRIZZLE OR FREEZING DRIZZLE THURSDAY
MORNING BEFORE CONDITIONS DRY OUT. A WEDGE OF HIGH PRESSURE WILL
BUILD DOWN THE COAST FRIDAY AND INTO THE WEEKEND BRINGING DRY BUT
COLD CONDITIONS. A WARMING TREND WILL DEVELOP NEXT WEEK ALONG WITH
INCREASING RAIN CHANCES.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 930 PM TUESDAY...PRECIP IS COMPLETELY OFFSHORE AND CLOUDY
SKIES ARE ANTICIPATED TO CONTINUE OVERNIGHT. LATEST HIGH-RES
MODELS SHOW WITH THE LACK OF ADVECTION ACROSS SOUTH CAROLINA
TEMPERATURES MAY NOT FALL MUCH (IF ANY) OVERNIGHT. IN FACT WITH
TEMPERATURES NOW ABOVE FREEZING AT BOTH MYRTLE BEACH AND KINGSTREE
I AM NOT CERTAIN THERE`S MUCH CONCERN FOR ICE ON ROADS ACROSS SOME
PARTS OF NE SOUTH CAROLINA. I HAVE RE-WRITTEN THE SPECIAL WEATHER
STATEMENT TO FOCUS CONCERN ON SE NORTH CAROLINA WHERE WE ARE
SEEING REPORTS OF MULTIPLE CLOSED BRIDGES AND ELEVATED ROADS IN
WILMINGTON.
DISCUSSION FROM 645 PM FOLLOWS...
ITS BEEN A HECTIC FEW HOURS HERE. A BAND OF MODERATE FREEZING RAIN
THAT EXTENDED AS FAR WEST AS THE SC MIDLANDS EARLIER THIS
AFTERNOON IS FINALLY PUSHING OFF THE COAST NEAR CAPE FEAR THIS
EVENING. THIS PRECIPITATION FELL PRIMARILY ACROSS SE NORTH
CAROLINA WHERE AIR TEMPERATURES WERE IN THE 28-31
RANGE...PRODUCING LARGE AMOUNTS OF FREEZING RAIN BETWEEN 2-6 PM.
THE FREEZING RAIN SENSOR AT THE ILM (WILMINGTON) ASOS REPORTED
0.40 INCHES OF ICE ACCRETION TODAY. NORMALLY OUTPUT FROM THIS
SENSOR AGREES QUITE WELL WITH HUMAN-OBSERVED ACCRETION ON ELEVATED
OBJECTS AT THE NWS OFFICE...BUT THE ASOS SENSOR APPEARS TO HAVE
RUN A LITTLE HIGH WITH ITS TOTALS TODAY AS WE ARE ESTIMATING
CLOSER TO 0.25 INCHES OF ICE ACCRETION HERE. REPORTS RECEIVED VIA
FACEBOOK AND TWITTER CONFIRM WIDESPREAD 0.25 INCH ICE
ACCUMULATIONS AROUND THE CAPE FEAR AREA TODAY...VERIFYING THE ICE
STORM WARNING THAT WAS ISSUED EARLIER.
RADAR ECHOES ARE PUSHING OFFSHORE AT 40 KNOTS...HOWEVER ASOS/AWOS
OBSERVATIONS AND A PHONE CALL FROM THE NCDOT IN LUMBERTON EARLIER
CONFIRMS THAT A COUPLE HOURS OF FREEZING DRIZZLE CONTINUES BEHIND
THE RADAR-OBSERVED BACK EDGE OF THE PRECIP SHIELD. FOR THIS REASON
I WILL MAINTAIN THE WATCHES AND ADVISORIES UNTIL 8 PM EAST OF
I-95.
FOR THE REMAINDER OF THE OVERNIGHT PERIOD...IT APPEARS LOW CLOUDS
WILL HOLD TOUGH FOR ALL BUT PERHAPS THE LUMBERTON-BENNETTSVILLE
AREA WHERE SOME LIMITED CLEARING MAY DEVELOP LATE TONIGHT AS
MOISTURE THINS FROM ALOFT. THIS WILL PREVENT ANY SIGNIFICANT
RADIATIONAL COOLING AND LOWS SHOULD RANGE FROM 26-30...COOLEST
NEAR LUMBERTON AND WARMEST NEAR GEORGETOWN. THE 12Z & 18Z GFS
BOTH APPEAR TO BE UP THE SAME ANTICS PULLED DURING LAST WEEK`S
ARCTIC COLD WHERE IT SEVERELY OVERESTIMATES RADIATIONAL COOLING
POTENTIAL OVER MEAGER SNOWPACK ACROSS MUCH OF NORTH CAROLINA. THE
18Z NAM AND 22Z RUC LOOK MUCH MORE REASONABLE FOR TEMPERATURES
OVERNIGHT.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 400 AM WEDNESDAY...BIGGEST CONCERN IN THE SHORT TERM INVOLVES
DEPARTING LOW PRESSURE THURSDAY...AND THE CHANCE FOR WINTRY PRECIP
ACROSS THE AREA.
CENTER OF STRENGTHENING LOW PRESSURE WILL BE OFF THE OUTER BANKS OF
NC TO START THURSDAY MORNING...AND WILL RAPIDLY PULL OFF TO THE
NORTHEAST THROUGH THURSDAY AFTN. ALTHOUGH THE MAJORITY OF THE
MOISTURE ASSOCIATED WITH THIS SYSTEM WILL FALL ON
WEDNESDAY...LOW-LEVEL RESIDUAL MOISTURE BELOW 700MB WILL REMAIN INTO
THURSDAY EVENING. THIS OF COURSE WILL NOT PRODUCE HEAVY PRECIP...BUT
VERY LIGHT RAIN AND DRIZZLE...ALONG WITH WIDESPREAD LOW
CLOUDINESS...WILL PERSIST INTO THURSDAY NIGHT. THE QUESTION IS HOW
QUICKLY CAN SURFACE TEMPS FALL BELOW FREEZING DURING
THURSDAY...WHICH WOULD CREATE A FREEZING DRIZZLE SCENARIO. GUIDANCE
IS IN VERY GOOD AGREEMENT WITH TEMPS REMAINING JUST ABOVE FREEZING
NEAR THE COAST...BUT DROPPING TO BELOW INLAND. FORTUNATELY...THE
BETTER CHANCE FOR RESIDUAL PRECIP IS NEAR THE COAST...AND EVEN IN
THOSE PLACES THAT DO ENCOUNTER SOME -ZL WILL DO SO ONTO GROUND THAT
HAS EXPERIENCED RAIN ON WEDNESDAY. LOCAL TOP DOWN METHODOLOGY
PRODUCED A SHORT PERIOD OF -ZR/-ZL ACROSS THE COUNTIES ALREADY
WITHIN THE WSW - SO EXTENDED THE WSW UNTIL NOON THURSDAY FOR SOME
VERY LIGHT FREEZING DRIZZLE WHICH MAY ACCRETE UP TO 0.01 OR 0.02
INCHES...MOSTLY ACROSS ROBESON/BLADEN COUNTIES.
AS THE LOW PULLS AWAY THURSDAY NIGHT DRY ADVECTION COMMENCES AND SKY
CONDITIONS WILL IMPROVE DRAMATICALLY FRIDAY...ALTHOUGH LOW CLOUD
COVER WILL REMAIN AS A WEDGE OF HIGH PRESSURE BUILDS DOWN THE COAST.
STILL...FRIDAY WILL BE DRY...A NICE BREAK FROM THE ACTIVE WEATHER
RECENTLY.
TEMPS THROUGH THE PERIOD WILL REMAIN WELL BELOW NORMAL AS THE
CALENDAR APPROACHES MARCH. HIGHS BOTH THURSDAY AND FRIDAY WILL BE
ONLY IN THE LOW 40S...A FULL 20 DEGREES BELOW NORMAL...ALTHOUGH
FRIDAY WILL BE THE SLIGHTLY WARMER OF THE TWO. LOWS AT NIGHT WILL
ALSO BE VERY COLD...DROPPING WELL INTO THE 20S BOTH NIGHTS...BUT IN
THE DRIER COLUMN FRIDAY NIGHT MINS WILL LIKELY BE 2-3 DEGREES COOLER
THAN THOSE EXPERIENCED ON THURSDAY NIGHT.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 400 AM WEDNESDAY...COLD AND DRY FOR THE WEEKEND...WITH A
WARMUP EXPECTED NEXT WEEK BUT ACCOMPANIED BY UNSETTLED WEATHER.
WEDGE OF HIGH PRESSURE WILL EXTEND DOWN THE EAST COAST DURING THE
WEEKEND AS CONFLUENCE BETWEEN THE EASTERN CONUS TROUGH AND
DEVELOPING SE RIDGE DRIVES RISING SURFACE PRESSURE. SATURDAY AND
SUNDAY WILL BOTH LIKELY BE DRY DAYS...BUT NE FLOW WITHIN THE WEDGE
WILL LEAD TO LOW CLOUDINESS THROUGH THE WEEKEND...BUT LIKELY IN A
VARYING STATE. THIS SUGGESTS THE SUN WILL BE PRESENT AT TIMES.
HOWEVER...TEMPS WILL...SHOCKINGLY...REMAIN WELL BELOW CLIMO THROUGH
THE WEEKEND.
WEDGE BREAKS DOWN ON MONDAY AND SURFACE HIGH PRESSURE SLIPS OFFSHORE
LEADING TO A DRAMATIC WARMING TREND FOR EARLY NEXT WEEK.
HOWEVER...THIS WARMTH WILL BE SOMEWHAT UNREALIZED AS UNSETTLED
WEATHER WILL DEVELOP MONDAY AND PERSIST THROUGH THE REMAINDER OF THE
PERIOD. LARGE TROUGH DEVELOPING WEST OF THE AREA WILL DRIVE
VORTICITY IMPULSES JUST NORTH OF THE AREA...OVERTOP A STALLED COLD
FRONT WHICH WILL HOVER ACROSS THE CAROLINAS. OVERALL...THERE APPEARS
TO BE LIMITED FORCING LOCALLY FOR PRECIP...BUT INCREASING CLOUDS
WITH AT LEAST PERIODS OF SHOWERS SEEM LIKELY MONDAY/TUESDAY.
&&
.AVIATION /09Z WEDNESDAY THROUGH SUNDAY/...
AS OF 05Z...IFR CONDITIONS WILL CONTINUE THROUGH THE PRE-DAWN HRS
OF WED WITH THE LOW CEILINGS THE PRIMARY REASON. WILL SEE VSBYS
DROP TO 2 TO 5 MILES IN FOG AT TIMES BUT THE LOW STRATUS WILL BE
THE PRIMARY AVIATION ISSUE THROUGH SEVERAL HRS AFTER SUNRISE WED.
NEXT SOUTHERN STREAM S/W TROF TO AFFECT THE FORECAST AREA WITH
ANOTHER ROUND OF WINTRY PCPN. DIFFERENCE WITH THIS NEXT SYSTEM IS
THAT COLD AIR WILL BE A LIMITING FACTOR THUS LEAVING ONLY THE
INLAND TERMINALS...FLO AND LBT...THAT COULD FACE POSSIBLE
FROZEN/FREEZING PCPN LATER TONIGHT INTO DAYTIME THU. AT THIS
TIME...THE CONSENSUS IS THAT THE COASTAL TERMINALS WILL BE JUST
PLAIN RAIN. THUS...LOW CEILINGS AND REDUCED HORIZONTAL VSBY TO
RETURN LATE IN THE TAF ISSUANCE PERIOD FOR ALL TERMINALS.
EXTENDED OUTLOOK...MVFR/IFR CONDITIONS EXPECTED AS LOW PRESSURE
WILL MOVE ACROSS THE TERMINALS TONITE INTO EARLY THU...THEN
ACCELERATE NE OFF THE CAROLINA COASTS AND OFFSHORE DURING THE DAY
ON THURSDAY. FINALLY...A RETURN TO VFR CONDITIONS FRI THROUGH
SAT. MVFR/IFR POSSIBLE SUNDAY.
&&
.MARINE...
.NEAR TERM /THROUGH TONIGHT/...
AS OF 930 PM TUESDAY...NO SIGNIFICANT CHANGES ARE NEEDED TO THE
FORECAST THIS EVENING AS WINDS AND SEAS ARE BEHAVING NICELY.
DISCUSSION FROM 645 PM FOLLOWS...
LOW PRESSURE WELL EAST OF THE SOUTH CAROLINA COAST WILL CONTINUE
TO PUSH NORTHEAST AND AWAY FROM THE AREA OVERNIGHT. THIS WILL
ALLOW WEAK HIGH PRESSURE INLAND TO SPREAD DOWN TO THE COAST
OVERNIGHT...WITH VEERING WINDS AND WEAKENING WIND SPEEDS. THE
SMALL CRAFT ADVISORY WILL REMAIN IN EFFECT FOR THE NC WATERS WHERE
THE FRYING PAN SHOALS BUOY IS STILL REPORTING 7.5 FOOT SEAS. WEST
OF FRYING PAN SHOALS CONDITIONS APPEAR TO BE IMPROVING A LITTLE
FASTER.
NOTE THAT SOME WIND SENSORS NEAR THE COAST APPEAR TO HAVE FROZEN
ANEMOMETER CUPS AND ARE NOT TO BE TRUSTED.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 400 AM WEDNESDAY...DEEPENING LOW PRESSURE WILL BE MOVING AWAY
FROM THE COAST DURING THURSDAY...BUT THE GRADIENT WILL REMAIN
PINCHED THE FIRST PART OF THE SHORT TERM. GUSTY NORTH WINDS WILL
REACH OVER 20 KTS FIRST THING THURSDAY...BUT WILL EASE QUICKLY
THROUGH THE AFTN TO BECOME 10-15 KTS THURSDAY NIGHT WHILE REMAINING
FROM THE NORTH. HIGH PRESSURE WILL BEGIN TO WEDGE DOWN THE COAST ON
FRIDAY...CAUSING RENEWED TIGHTENING OF THE GRADIENT...AND WINDS WILL
INCREASE SLOWLY...BECOMING 20-25 KTS ONCE AGAIN BUT FROM MORE OF A
NE DIRECTION FRIDAY NIGHT. SEAS THURSDAY MORNING WILL BE 5-8
FT...BUT WILL FALL QUICKLY THROUGH THE DAY AND THE ONGOING SCA
SHOULD BE ALLOWED TO EXPIRE LATE THURSDAY. SEAS WILL REMAIN BELOW 6
FT THURSDAY NIGHT AND FRIDAY...BUT WILL RISE ONCE AGAIN TO 4-6 FT
FRIDAY NIGHT WHEN A RENEWED SCA MAY BE NEEDED.
LONG TERM /SATURDAY THROUGH SUNDAY/...
AS OF 400 AM WEDNESDAY...WEDGE OF HIGH PRESSURE WILL STRENGTHEN
SATURDAY...AND AN EXTENDED PERIOD OF GUSTY 20-25 KT NE WINDS WILL
OCCUR THROUGH SATURDAY. THIS DRIVES WAVE HEIGHTS TO 4-6 FT...AND AN
SCA WILL LIKELY BE NEEDED THROUGH SATURDAY. SATURDAY
NIGHT...GRADIENT SLOWLY BEGINS TO WEAKEN AS THE WEDGE BREAKS DOWN.
THIS CAUSES WINDS TO EASE TO 10-15 KTS BY SUNDAY MORNING WHILE
REMAINING FROM THE NE. WINDS WILL EASE FURTHER AND THEN VEER TO THE
SOUTH AS THE WEDGE DISSIPATES LATE SUNDAY. WAVE HEIGHTS FALL ON THE
DECREASING WINDS...FROM 4-6 FT LATE SATURDAY...TO 2-4 FT SUNDAY.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO NOON EST
THURSDAY FOR SCZ017-023-024.
NC...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO NOON EST
THURSDAY FOR NCZ087-096-105.
MARINE...NONE.
&&
$$
SYNOPSIS...JDW
NEAR TERM...DCH/TRA
SHORT TERM...JDW
LONG TERM...JDW
AVIATION...DCH
MARINE...DCH/TRA/JDW
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
133 AM EST WED FEB 25 2015
.SYNOPSIS...
LOW PRESSURE WILL PULL AWAY FROM THE CAROLINAS TONIGHT AS WEAK
HIGH PRESSURE BUILDS OVERHEAD. A STRONG STORM SYSTEM WILL BRING
RAIN AND POSSIBLY SNOW WELL INLAND LATE WEDNESDAY INTO THURSDAY
MORNING. A MINOR WARMING TREND WILL BEGIN OVER THE WEEKEND.
MOISTURE WILL RETURN EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 930 PM TUESDAY...PRECIP IS COMPLETELY OFFSHORE AND CLOUDY
SKIES ARE ANTICIPATED TO CONTINUE OVERNIGHT. LATEST HIGH-RES
MODELS SHOW WITH THE LACK OF ADVECTION ACROSS SOUTH CAROLINA
TEMPERATURES MAY NOT FALL MUCH (IF ANY) OVERNIGHT. IN FACT WITH
TEMPERATURES NOW ABOVE FREEZING AT BOTH MYRTLE BEACH AND KINGSTREE
I AM NOT CERTAIN THERE`S MUCH CONCERN FOR ICE ON ROADS ACROSS SOME
PARTS OF NE SOUTH CAROLINA. I HAVE RE-WRITTEN THE SPECIAL WEATHER
STATEMENT TO FOCUS CONCERN ON SE NORTH CAROLINA WHERE WE ARE
SEEING REPORTS OF MULTIPLE CLOSED BRIDGES AND ELEVATED ROADS IN
WILMINGTON.
DISCUSSION FROM 645 PM FOLLOWS...
ITS BEEN A HECTIC FEW HOURS HERE. A BAND OF MODERATE FREEZING RAIN
THAT EXTENDED AS FAR WEST AS THE SC MIDLANDS EARLIER THIS
AFTERNOON IS FINALLY PUSHING OFF THE COAST NEAR CAPE FEAR THIS
EVENING. THIS PRECIPITATION FELL PRIMARILY ACROSS SE NORTH
CAROLINA WHERE AIR TEMPERATURES WERE IN THE 28-31
RANGE...PRODUCING LARGE AMOUNTS OF FREEZING RAIN BETWEEN 2-6 PM.
THE FREEZING RAIN SENSOR AT THE ILM (WILMINGTON) ASOS REPORTED
0.40 INCHES OF ICE ACCRETION TODAY. NORMALLY OUTPUT FROM THIS
SENSOR AGREES QUITE WELL WITH HUMAN-OBSERVED ACCRETION ON ELEVATED
OBJECTS AT THE NWS OFFICE...BUT THE ASOS SENSOR APPEARS TO HAVE
RUN A LITTLE HIGH WITH ITS TOTALS TODAY AS WE ARE ESTIMATING
CLOSER TO 0.25 INCHES OF ICE ACCRETION HERE. REPORTS RECEIVED VIA
FACEBOOK AND TWITTER CONFIRM WIDESPREAD 0.25 INCH ICE
ACCUMULATIONS AROUND THE CAPE FEAR AREA TODAY...VERIFYING THE ICE
STORM WARNING THAT WAS ISSUED EARLIER.
RADAR ECHOES ARE PUSHING OFFSHORE AT 40 KNOTS...HOWEVER ASOS/AWOS
OBSERVATIONS AND A PHONE CALL FROM THE NCDOT IN LUMBERTON EARLIER
CONFIRMS THAT A COUPLE HOURS OF FREEZING DRIZZLE CONTINUES BEHIND
THE RADAR-OBSERVED BACK EDGE OF THE PRECIP SHIELD. FOR THIS REASON
I WILL MAINTAIN THE WATCHES AND ADVISORIES UNTIL 8 PM EAST OF
I-95.
FOR THE REMAINDER OF THE OVERNIGHT PERIOD...IT APPEARS LOW CLOUDS
WILL HOLD TOUGH FOR ALL BUT PERHAPS THE LUMBERTON-BENNETTSVILLE
AREA WHERE SOME LIMITED CLEARING MAY DEVELOP LATE TONIGHT AS
MOISTURE THINS FROM ALOFT. THIS WILL PREVENT ANY SIGNIFICANT
RADIATIONAL COOLING AND LOWS SHOULD RANGE FROM 26-30...COOLEST
NEAR LUMBERTON AND WARMEST NEAR GEORGETOWN. THE 12Z & 18Z GFS
BOTH APPEAR TO BE UP THE SAME ANTICS PULLED DURING LAST WEEK`S
ARCTIC COLD WHERE IT SEVERELY OVERESTIMATES RADIATIONAL COOLING
POTENTIAL OVER MEAGER SNOWPACK ACROSS MUCH OF NORTH CAROLINA. THE
18Z NAM AND 22Z RUC LOOK MUCH MORE REASONABLE FOR TEMPERATURES
OVERNIGHT.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH THURSDAY NIGHT/...
AS OF 300 PM TUESDAY...MAIN FORECAST EMPHASIS IS THE STORM SYSTEM
CURRENTLY TAKING SHAPE IN THE NEW MEXICO REGION. THIS SYSTEM WILL
RACE ACROSS THE SOUTHERN STATES OVER THE NEXT 24-48 HOURS IN WHAT
IS BASICALLY A WESTERLY FLOW ALOFT. LOW PRESSURE WILL DEVELOP IN
THE GULF OF MEXICO AND MOVE OFFSHORE...EAST OF CHARLESTON BY 0600
UTC THURSDAY. BY 1200 UTC THURSDAY THE LOW WILL BE WELL EAST OF
THE OUTER BANKS.
FORCING WITH THE SYSTEM WILL COME IN A COUPLED FASHION WITH LOWER
LEVEL ISENTROPIC LIFT ON THE 290K SURFACE AND MID LEVEL
FRONTOGENESIS. THE DOMINANT COMPONENT IS BY FAR THE ISENTROPIC LIFT
AND THIS OF COURSE LEADS TO PRECIPITATION TYPE ISSUES ACROSS MOST OF
THE AREA.
FOR THE MOST PART...THERMAL PROFILES SUPPORT RAIN INITIALLY. AS
DYNAMIC COOLING TAKES PLACE ALONG WITH HEAVIER QPF RATES SOUNDINGS
COOL IN THE NORTHERN MOST COUNTIES TO MARGINALLY SUPPORT SNOW. THE
MODELS IF ANYTHING HAVE TRENDED JUST A LITTLE WARMER HOWEVER AND
CONFIDENCE IS NOT OVERWHELMING. THAT BEING SAID IF THE DYNAMIC LIFT
IS A LITTLE STRONGER THAN PERFECT PROGS...A COOLING OF THE PROFILE
COULD OCCUR WHICH WOULD LEAD TO MORE SUPPORT FOR SNOW. FOR NOW...I
HAVE A RAIN AND SNOW MIX FOR MARLBORO...ROBESON AND BLADEN COUNTIES
AND TOTAL ACCUMULATIONS OF JUST OVER TWO INCHES. THIS WARRANTS A
WINTER STORM WATCH FOR THESE AREAS WHICH WILL BE RAISED THIS
AFTERNOON. IT COULD BE A SITUATION WHERE SNOW IS THE PREDOMINANT
TYPE WITH RAIN MIXING FROM TIME TO TIME...AT LEAST A COUPLE OF HOURS
EITHER SIDE OF 0600 UTC. OVERALL I CANT RULE OUT A COUPLE OF INCHES
OF VERY WET/HEAVY SNOW IN THESE AREAS. IF SNOW DOES INDEED
DEVELOP...IT WONT TAKE LONG TO ACCUMULATE AS THE RATES SHOULD BE
VERY HIGH...AGAIN AT LEAST FOR A COUPLE OF HOURS EITHER SIDE OF 0600
UTC.
AS THE SYSTEM MOVES OUT BEYOND 0600 UTC PROFILES BRIEFLY SUPPORT
SOME SNOW IN OTHER AREAS AND I HAVE AMOUNTS RANGING FROM 0.7 INCHES
FROM NORTHWEST TO JUST OVER ONE HALF OF IN INCH CLOSER TO THE COAST.
THIS CAN PROBABLY BE ADDRESSED WITH A WINTER WEATHER
ADVISORY...ALTHOUGH TECHNICALLY JUST UNDER CRITERIA BUT WITH A
WINTER STORM WATCH FLOATING AROUND...IT MAY BE PRUDENT TO ISSUE AN
ADVISORY FOR PUBLIC IMPACT...AFTER THE CURRENT ONE HAS EXPIRED.
THE REMAINDER OF THURSDAY WILL FEATURE OVERCAST SKIES WITH PATCHY
DRIZZLE. HIGH TEMPERATURES WILL STRUGGLE TO REACH 40. YET ANOTHER
COLD AND BLUSTERY OVERNIGHT PERIOD FOR THURSDAY INTO FRIDAY MORNING
WITH LOWS IN THE MIDDLE 20S.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 300 PM TUESDAY...BROAD LOW AMPLITUDE MID LEVEL FLOW ACROSS MOST
OF THE CONUS ON FRIDAY WITH LARGE HIGH PRESSURE AT THE SURFACE
CENTERED OVER EASTERN U.S. THIS WILL BRING A NORTHERLY FLOW LOCALLY
THAT WILL KEEP TEMPERATURES BELOW CLIMO AND LIKELY QUITE A FEW
CLOUDS TRAPPED UNDER AN INVERSION. NOT MUCH CHANGES HEADING INTO
SATURDAY AND SO THE FORECAST IS QUITE SIMILAR. ON SUNDAY THE CENTER
OF THE SURFACE HIGH SLIDES EAST AND EXTENDS A WEDGE AXIS INTO THE
CAROLINAS WHILE OFFSHORE TROUGHINESS DEVELOPS. MODELS LOOKING WETTER
AS THIS OCCURS AS WARM ADVECTION RIDES ATOP THIS SURFACE-BASED
AIRMASS LEADS TO GOOD ISENTROPIC UPGLIDE. GUIDANCE ALSO SUGGESTING A
MILDER AFTERNOON BUT THIS MAY NEED TO BE REVISITED ESPECIALLY IF
RAIN DOES MATERIALIZE. THE WEDGE BREAKS DOWN RAPIDLY BY MONDAY
ALLOWING FOR MODERATION IN TEMPERATURES AND PERHAPS SOME
UNSEASONABLY MILD NIGHTS BUT THE MOISTURE WILL REMAIN AND SOME
LIGHT RAIN CHANCES ARE STILL WARRANTED IF NOTHING ELSE DUE TO THE
APPROACH OF A WEAK COLD FRONT. THIS BOUNDARY APPEARS TO STALL ACROSS
THE AREA ON TUESDAY KEEPING CLOUDS AND RAIN IN THE FORECAST.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
AS OF 05Z...IFR CONDITIONS WILL CONTINUE THROUGH THE PRE-DAWN HRS
OF WED WITH THE LOW CEILINGS THE PRIMARY REASON. WILL SEE VSBYS
DROP TO 2 TO 5 MILES IN FOG AT TIMES BUT THE LOW STRATUS WILL BE
THE PRIMARY AVIATION ISSUE THROUGH SEVERAL HRS AFTER SUNRISE WED.
NEXT SOUTHERN STREAM S/W TROF TO AFFECT THE FORECAST AREA WITH
ANOTHER ROUND OF WINTRY PCPN. DIFFERENCE WITH THIS NEXT SYSTEM IS
THAT COLD AIR WILL BE A LIMITING FACTOR THUS LEAVING ONLY THE
INLAND TERMINALS...FLO AND LBT...THAT COULD FACE POSSIBLE
FROZEN/FREEZING PCPN LATER TONIGHT INTO DAYTIME THU. AT THIS
TIME...THE CONSENSUS IS THAT THE COASTAL TERMINALS WILL BE JUST
PLAIN RAIN. THUS...LOW CEILINGS AND REDUCED HORIZONTAL VSBY TO
RETURN LATE IN THE TAF ISSUANCE PERIOD FOR ALL TERMINALS.
EXTENDED OUTLOOK...MVFR/IFR CONDITIONS EXPECTED AS LOW PRESSURE
WILL MOVE ACROSS THE TERMINALS TONITE INTO EARLY THU...THEN
ACCELERATE NE OFF THE CAROLINA COASTS AND OFFSHORE DURING THE DAY
ON THURSDAY. FINALLY...A RETURN TO VFR CONDITIONS FRI THROUGH
SAT. MVFR/IFR POSSIBLE SUNDAY.
&&
.MARINE...
.NEAR TERM /THROUGH TONIGHT/...
AS OF 930 PM TUESDAY...NO SIGNIFICANT CHANGES ARE NEEDED TO THE
FORECAST THIS EVENING AS WINDS AND SEAS ARE BEHAVING NICELY.
DISCUSSION FROM 645 PM FOLLOWS...
LOW PRESSURE WELL EAST OF THE SOUTH CAROLINA COAST WILL CONTINUE
TO PUSH NORTHEAST AND AWAY FROM THE AREA OVERNIGHT. THIS WILL
ALLOW WEAK HIGH PRESSURE INLAND TO SPREAD DOWN TO THE COAST
OVERNIGHT...WITH VEERING WINDS AND WEAKENING WIND SPEEDS. THE
SMALL CRAFT ADVISORY WILL REMAIN IN EFFECT FOR THE NC WATERS WHERE
THE FRYING PAN SHOALS BUOY IS STILL REPORTING 7.5 FOOT SEAS. WEST
OF FRYING PAN SHOALS CONDITIONS APPEAR TO BE IMPROVING A LITTLE
FASTER.
NOTE THAT SOME WIND SENSORS NEAR THE COAST APPEAR TO HAVE FROZEN
ANEMOMETER CUPS AND ARE NOT TO BE TRUSTED.
SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 300 PM TUESDAY...COASTAL WATERS WILL SEE A BRIEF RESPITE FROM
RUGGED CONDITIONS EARLY WEDNESDAY AS WINDS WILL BE RELATIVELY LIGHT
FROM THE NORTHWEST...TEN KNOTS OR LESS AS LOW PRESSURE DEVELOPS AND
MOVES WELL OFFSHORE...WINDS WILL TURN TO THE NORTHEAST AND INCREASE
IN MAGNITUDE TO 20-25 KNOTS BY EARLY THURSDAY MORNING. WINDS TURN TO
A MORE NORTHERLY DIRECTION DURING THE DAY THURSDAY AND SEEM
CONSISTENT IN A 10-15 KNOT RANGE...MOSTLY LEANING TOWARD THE HIGHER
SIDE. SIGNIFICANT SEAS START OUT SLOW AS WELL 1-2 FEET THEN RAMP UP
WELL INTO SMALL CRAFT CRITERIA BY LATE THURSDAY EVENING. BY LATE
THURSDAY HEIGHTS DROP BACK A BIT PROBABLY BELOW SMALL CRAFT
CRITERIA.
LONG TERM /FRIDAY THROUGH SUNDAY/...
AS OF 300 PM TUESDAY...A LARGE AREA OF HIGH PRESSURE COVERING THE
EASTERN U.S. TO BRING A NORTHERLY WIND LOCALLY THAT WILL BE MODERATE
BUT NO FLAGS EXPECTED AT THIS TIME. THE CENTER OF THIS HIGH WILL
SHIFT EAST A BIT ON SATURDAY BUT THE LOCAL EFFECTS WILL BE THOSE OF
MINIMAL CHANGE. THE INCREASED DURATION OF THE LARGELY
COAST-PARALLEL NE WINDS COULD ALLOW FOR AN UPTICK IN OFFSHORE SEAS
BUT FOR NOW IT STILL SEEMS NO ADVISORIES WILL COME TO PASS. 5 FT
SEAS WILL BE QUITE PREVALENT ACROSS MOST ZONES AWAY FROM SHORE BUT
THE NEARSHORE WAVE SHADOWING MAY PRECLUDE EVEN CAUTIONARY HEADLINES.
THE HIGH SHIFTS FURTHER EAST ON SUNDAY AND EXTENDS A RIDGE AXIS ITO
THE CAROLINAS WHILE TROUGHINESS DEVELOPS JUST EAST OF THE FORECAST
WATERS. THIS HAS CAST SOME UNCERTAINTY ON THE FORECAST AS WIND SPEED
AND EVEN DIRECTION COULD VARY CONSIDERABLY DEPENDING ON WHERE THE
TROUGH-BORN WIND SHIFT DECIDES TO SET UP. CURRENTLY IT SEEMS TO BE
JUST FAR ENOUGH OFFSHORE THAT LOCAL WINDS STAY NORTHEASTERLY AND
GROW A BIT LIGHTER.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...WINTER STORM WATCH FROM THIS EVENING THROUGH THURSDAY MORNING
FOR SCZ017.
NC...WINTER STORM WATCH FROM THIS EVENING THROUGH THURSDAY MORNING
FOR NCZ087-096.
MARINE...NONE.
&&
$$
SYNOPSIS...SHK
NEAR TERM...TRA
SHORT TERM...SHK
LONG TERM...MBB
AVIATION...DCH
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1247 PM CST WED FEB 25 2015
.UPDATE...
ISSUED AT 1247 PM CST WED FEB 25 2015
LIGHT SNOW ENDED IN THE FAR SOUTHWEST SO MADE SOME ADJUSTMENTS TO
POP AND SKY. OTHERWISE...REST OF FORECAST ON TARGET AS COLD
CANADIAN HIGH PRESSURE CONTINUES TO SHIFT SOUTH ACROSS THE AREA.
UPDATE ISSUED AT 942 AM CST WED FEB 25 2015
LIGHT SNOW CONTINUES TO LINGER OVER THE EXTREME SE CORNER OF
NORTH DAKOTA SO KEPT LOW POPS GOING UNTIL ABOUT 18Z. WIND CHILLS
HAVE WARMED TO ABOVE ADVISORY CRITERIA AND THE ADVISORY HAS BEEN
CANCELED. OTHERWISE...REST OF FORECAST LOOKS GOOD.
UPDATE ISSUED AT 652 AM CST WED FEB 25 2015
TWEAKED POPS BASED ON CURRENT RADAR TRENDS BUT WILL CONTINUE WITH
HIGH PROBABILITIES FOR THE NEXT FEW HOURS AS SHORT RANGE MODELS ALL
HAVE LIGHT SNOW HANGING AROUND IN THE SOUTHWESTERN COUNTIES UNTIL
13 TO 14Z. ANY ADDITIONAL ACCUMULATIONS SHOULD BE MINIMAL.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 324 AM CST WED FEB 25 2015
SNOW THIS MORNING AND WIND CHILLS TONIGHT WILL BE THE PRIMARY
FORECAST CHALLENGE FOR THE SHORT TERM.
NORTHWESTERLY FLOW ALOFT CONTINUES WITH A WEAK REINFORCING
SHORTWAVE DIGGING THROUGH THE DAKOTAS. THE BAND OF SNOW HAS BEEN A
BIT FURTHER EAST THAN EXPECTED...AND VALLEY CITY HAS BEEN DOWN TO
2SM WITH LIGHT SNOW AND IT LOOKS LIKE GWINNER HAS FINALLY
SATURATED AND IS GETTING SOME SNOW AT THE SFC. THE BAND MATCHES UP
WITH THE 850-700MB FRONTOGENESIS FAIRLY WELL...AND THE NAM HAS
THAT AREA STARTING TO MOVE OFF TO THE SOUTH LATER THIS MORNING.
THAT SEEMS TO FIT PRETTY WELL WITH THE RAP AND HRRR WHICH HAVE THE
QPF PEAKING AROUND 10Z AND THEN TAPERING OFF 3 TO 4 HOURS LATER.
TIME HEIGHT PLOTS FOR OUR SOUTHWESTERN CWA HAVE A GOOD OMEGA
BULLSEYE IN THE GOOD DENDRITIC GROWTH ZONE UNTIL AROUND 12Z.
CONTINUED TREND OF CATEGORICAL POPS IN THE FAR WEST FOR EARLY THIS
MORNING...WITH SOME ADJUSTMENTS FOR CURRENT RADAR TRENDS. RAP PUTS
OUT NEARLY 3 INCHES IN FAR SOUTHERN SARGENT COUNTY...BUT THIS
SEEMS A BIT HIGH GIVEN HOW LONG IT HAS TAKEN OBS SITES TO
SATURATE. CONTINUED WITH 1 TO 2 INCHES IN THE FAR SOUTHWESTERN CWA.
THE PRECIP SHOULD TAPER OFF BY MID MORNING AND WE WILL SEE
DECREASING CLOUDS MOVE SOUTH AS ARCTIC HIGH PRESSURE BUILDS INTO
THE NORTHERN PLAINS. THE HIGH WILL CONTINUE INTO TONIGHT AS THE
MAIN UPPER TROUGH CONTINUES TO DIG SOUTHEASTWARD. WITH CLEARING
SKIES AND THE COLD AIR MASS...WE SHOULD AGAIN GET DOWN TO THE -10
TO -20 RANGE TONIGHT. WINDS WILL DECREASE AS THE CENTER OF THE
HIGH MOVES DOWN INTO WESTERN ND...BUT THINK WE SHOULD HAVE ENOUGH
GRADIENT TO BRING WIND CHILLS DOWN TO ADVISORY LEVELS TONIGHT.
GIVEN THAT THERE IS A CURRENT HEADLINE FOR OUR NORTHEASTERN
COUNTIES AND WIND CHILL ADVISORIES ARE BECOMING A DIME A
DOZEN...WILL HOLD OFF ON ISSUING ONE FOR NOW. THE COLD HIGH
PRESSURE WILL REMAIN THROUGH THURSDAY WITH HIGHS JUST ABOVE ZERO.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 324 AM CST WED FEB 25 2015
THURSDAY NIGHT THROUGH FRIDAY NIGHT...NORTHWESTERLY FLOW ALOFT
CONTINUES WITH THE CENTER OF THE SFC HIGH FINALLY STARTING TO MOVE
SOUTH AND EAST. WIND CHILLS COULD AGAIN BE AN ISSUE THURSDAY NIGHT
INTO FRIDAY MORNING. THE SOUTHERLY WINDS WILL INCREASE MORE ON
FRIDAY AS HIGH PULLS FURTHER AWAY. TEMPS SHOULD GET UP TO AROUND
10 BY FRIDAY AFTERNOON UNDER THE LATE WINTER SUN BUT WILL STILL BE
WELL BELOW AVERAGE AND WILL FEEL PRETTY RAW WITH THE INCREASING
WINDS. WEAK WARM AIR ADVECTION AND WINDS KEEPING US MIXED WILL
ALLOW TEMPS FRIDAY NIGHT TO FALL ONLY SLIGHTLY BELOW ZERO INSTEAD
OF THE TEENS BELOW.
SATURDAY TO WEDNESDAY...MODELS IN GOOD AGREEMENT WITH THE EXTENDED
LEADING TO HIGH CONFIDENCE FOR MUCH OF THE WEEKEND AND FIRST PART OF
NEXT WEEK. DRY WEATHER WILL CONTINUE ACROSS THE NORTHERN PLAINS WITH
THE ONLY SLGHT CHC FOR -SN BEING TUESDAY INTO WEDNESDAY FOR THE
SOUTHERN AND EASTERN PORTIONS OF THE AREA. 500MB SPLIT FLOW
CONTINUES WITH WESTERN CONUS THROUGH AMPLIFYING INTO THE FIRST PART
OF NEXT WEEK THE 500MB SW TO NE ORIENTED TROUGH AXIS PUSHES ACROSS
THE FA ON TUESDAY...BRINGING THE -SN POTENTIAL. TEMPERATURES NEAR
SEASONAL NORMALS WITH HIGHS IN THE 20S SAT-TUE WITH POST FROPA COLD
FOR WEDNESDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1247 PM CST WED FEB 25 2015
VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD...WITH NW WINDS
SLOWLY DECREASING OVERNIGHT. WINDS COULD GUST OVER 20KT THIS
AFTERNOON...ALONG WITH THE POTENTIAL FOR SOME LOWER STRATOCUMULUS
POSSIBLE. WILL MONITOR THIS...BUT FOR NOW HAVE NOT MENTIONED ANY
CIGS THIS AFTERNOON OR STRONGER WINDS.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...HOPKINS
SHORT TERM...JR
LONG TERM...JR/JK
AVIATION...DK
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
942 AM CST WED FEB 25 2015
.UPDATE...
ISSUED AT 942 AM CST WED FEB 25 2015
LIGHT SNOW CONTINUES TO LINGER OVER THE EXTREME SE CORNER OF
NORTH DAKOTA SO KEPT LOW POPS GOING UNTIL ABOUT 18Z. WIND CHILLS
HAVE WARMED TO ABOVE ADVISORY CRITERIA AND THE ADVISORY HAS BEEN
CANCELED. OTHERWISE...REST OF FORECAST LOOKS GOOD.
UPDATE ISSUED AT 652 AM CST WED FEB 25 2015
TWEAKED POPS BASED ON CURRENT RADAR TRENDS BUT WILL CONTINUE WITH
HIGH PROBABILITIES FOR THE NEXT FEW HOURS AS SHORT RANGE MODELS ALL
HAVE LIGHT SNOW HANGING AROUND IN THE SOUTHWESTERN COUNTIES UNTIL
13 TO 14Z. ANY ADDITIONAL ACCUMULATIONS SHOULD BE MINIMAL.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 324 AM CST WED FEB 25 2015
SNOW THIS MORNING AND WIND CHILLS TONIGHT WILL BE THE PRIMARY
FORECAST CHALLENGE FOR THE SHORT TERM.
NORTHWESTERLY FLOW ALOFT CONTINUES WITH A WEAK REINFORCING
SHORTWAVE DIGGING THROUGH THE DAKOTAS. THE BAND OF SNOW HAS BEEN A
BIT FURTHER EAST THAN EXPECTED...AND VALLEY CITY HAS BEEN DOWN TO
2SM WITH LIGHT SNOW AND IT LOOKS LIKE GWINNER HAS FINALLY
SATURATED AND IS GETTING SOME SNOW AT THE SFC. THE BAND MATCHES UP
WITH THE 850-700MB FRONTOGENESIS FAIRLY WELL...AND THE NAM HAS
THAT AREA STARTING TO MOVE OFF TO THE SOUTH LATER THIS MORNING.
THAT SEEMS TO FIT PRETTY WELL WITH THE RAP AND HRRR WHICH HAVE THE
QPF PEAKING AROUND 10Z AND THEN TAPERING OFF 3 TO 4 HOURS LATER.
TIME HEIGHT PLOTS FOR OUR SOUTHWESTERN CWA HAVE A GOOD OMEGA
BULLSEYE IN THE GOOD DENDRITIC GROWTH ZONE UNTIL AROUND 12Z.
CONTINUED TREND OF CATEGORICAL POPS IN THE FAR WEST FOR EARLY THIS
MORNING...WITH SOME ADJUSTMENTS FOR CURRENT RADAR TRENDS. RAP PUTS
OUT NEARLY 3 INCHES IN FAR SOUTHERN SARGENT COUNTY...BUT THIS
SEEMS A BIT HIGH GIVEN HOW LONG IT HAS TAKEN OBS SITES TO
SATURATE. CONTINUED WITH 1 TO 2 INCHES IN THE FAR SOUTHWESTERN CWA.
THE PRECIP SHOULD TAPER OFF BY MID MORNING AND WE WILL SEE
DECREASING CLOUDS MOVE SOUTH AS ARCTIC HIGH PRESSURE BUILDS INTO
THE NORTHERN PLAINS. THE HIGH WILL CONTINUE INTO TONIGHT AS THE
MAIN UPPER TROUGH CONTINUES TO DIG SOUTHEASTWARD. WITH CLEARING
SKIES AND THE COLD AIR MASS...WE SHOULD AGAIN GET DOWN TO THE -10
TO -20 RANGE TONIGHT. WINDS WILL DECREASE AS THE CENTER OF THE
HIGH MOVES DOWN INTO WESTERN ND...BUT THINK WE SHOULD HAVE ENOUGH
GRADIENT TO BRING WIND CHILLS DOWN TO ADVISORY LEVELS TONIGHT.
GIVEN THAT THERE IS A CURRENT HEADLINE FOR OUR NORTHEASTERN
COUNTIES AND WIND CHILL ADVISORIES ARE BECOMING A DIME A
DOZEN...WILL HOLD OFF ON ISSUING ONE FOR NOW. THE COLD HIGH
PRESSURE WILL REMAIN THROUGH THURSDAY WITH HIGHS JUST ABOVE ZERO.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 324 AM CST WED FEB 25 2015
THURSDAY NIGHT THROUGH FRIDAY NIGHT...NORTHWESTERLY FLOW ALOFT
CONTINUES WITH THE CENTER OF THE SFC HIGH FINALLY STARTING TO MOVE
SOUTH AND EAST. WIND CHILLS COULD AGAIN BE AN ISSUE THURSDAY NIGHT
INTO FRIDAY MORNING. THE SOUTHERLY WINDS WILL INCREASE MORE ON
FRIDAY AS HIGH PULLS FURTHER AWAY. TEMPS SHOULD GET UP TO AROUND
10 BY FRIDAY AFTERNOON UNDER THE LATE WINTER SUN BUT WILL STILL BE
WELL BELOW AVERAGE AND WILL FEEL PRETTY RAW WITH THE INCREASING
WINDS. WEAK WARM AIR ADVECTION AND WINDS KEEPING US MIXED WILL
ALLOW TEMPS FRIDAY NIGHT TO FALL ONLY SLIGHTLY BELOW ZERO INSTEAD
OF THE TEENS BELOW.
SATURDAY TO WEDNESDAY...MODELS IN GOOD AGREEMENT WITH THE EXTENDED
LEADING TO HIGH CONFIDENCE FOR MUCH OF THE WEEKEND AND FIRST PART OF
NEXT WEEK. DRY WEATHER WILL CONTINUE ACROSS THE NORTHERN PLAINS WITH
THE ONLY SLGHT CHC FOR -SN BEING TUESDAY INTO WEDNESDAY FOR THE
SOUTHERN AND EASTERN PORTIONS OF THE AREA. 500MB SPLIT FLOW
CONTINUES WITH WESTERN CONUS THROUGH AMPLIFYING INTO THE FIRST PART
OF NEXT WEEK THE 500MB SW TO NE ORIENTED TROUGH AXIS PUSHES ACROSS
THE FA ON TUESDAY...BRINGING THE -SN POTENTIAL. TEMPERATURES NEAR
SEASONAL NORMALS WITH HIGHS IN THE 20S SAT-TUE WITH POST FROPA COLD
FOR WEDNESDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 652 AM CST WED FEB 25 2015
LIGHT SNOW CONTINUES TO THE SOUTHWEST OF TAF SITES...WHICH ALL
HAVE VFR CIGS IF ANY AT ALL. CIGS OF 5000-10000 FT WILL REMAIN
OVER MUCH OF THE AREA THIS MORNING BEFORE THE SYSTEM PULLS FURTHER
SOUTH AND WE BEGIN TO CLEAR OUT FOR TONIGHT. NORTHEAST WINDS WILL
SHIFT TO THE NORTH TO NORTHWEST AND INCREASE A BIT...UP TO THE 15
TO 20 KT RANGE IN PLACES. HIGH PRESSURE BUILDING IN SHOULD ALLOW
THE WINDS TO DECREASE AFTER SUNSET.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...HOPKINS
SHORT TERM...JR
LONG TERM...JR/JK
AVIATION...JR
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
652 AM CST WED FEB 25 2015
.UPDATE...
ISSUED AT 652 AM CST WED FEB 25 2015
TWEAKED POPS BASED ON CURRENT RADAR TRENDS BUT WILL CONTINUE WITH
HIGH PROBABILITIES FOR THE NEXT FEW HOURS AS SHORT RANGE MODELS ALL
HAVE LIGHT SNOW HANGING AROUND IN THE SOUTHWESTERN COUNTIES UNTIL
13 TO 14Z. ANY ADDITIONAL ACCUMULATIONS SHOULD BE MINIMAL.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 324 AM CST WED FEB 25 2015
SNOW THIS MORNING AND WIND CHILLS TONIGHT WILL BE THE PRIMARY
FORECAST CHALLENGE FOR THE SHORT TERM.
NORTHWESTERLY FLOW ALOFT CONTINUES WITH A WEAK REINFORCING
SHORTWAVE DIGGING THROUGH THE DAKOTAS. THE BAND OF SNOW HAS BEEN A
BIT FURTHER EAST THAN EXPECTED...AND VALLEY CITY HAS BEEN DOWN TO
2SM WITH LIGHT SNOW AND IT LOOKS LIKE GWINNER HAS FINALLY
SATURATED AND IS GETTING SOME SNOW AT THE SFC. THE BAND MATCHES UP
WITH THE 850-700MB FRONTOGENESIS FAIRLY WELL...AND THE NAM HAS
THAT AREA STARTING TO MOVE OFF TO THE SOUTH LATER THIS MORNING.
THAT SEEMS TO FIT PRETTY WELL WITH THE RAP AND HRRR WHICH HAVE THE
QPF PEAKING AROUND 10Z AND THEN TAPERING OFF 3 TO 4 HOURS LATER.
TIME HEIGHT PLOTS FOR OUR SOUTHWESTERN CWA HAVE A GOOD OMEGA
BULLSEYE IN THE GOOD DENDRITIC GROWTH ZONE UNTIL AROUND 12Z.
CONTINUED TREND OF CATEGORICAL POPS IN THE FAR WEST FOR EARLY THIS
MORNING...WITH SOME ADJUSTMENTS FOR CURRENT RADAR TRENDS. RAP PUTS
OUT NEARLY 3 INCHES IN FAR SOUTHERN SARGENT COUNTY...BUT THIS
SEEMS A BIT HIGH GIVEN HOW LONG IT HAS TAKEN OBS SITES TO
SATURATE. CONTINUED WITH 1 TO 2 INCHES IN THE FAR SOUTHWESTERN CWA.
THE PRECIP SHOULD TAPER OFF BY MID MORNING AND WE WILL SEE
DECREASING CLOUDS MOVE SOUTH AS ARCTIC HIGH PRESSURE BUILDS INTO
THE NORTHERN PLAINS. THE HIGH WILL CONTINUE INTO TONIGHT AS THE
MAIN UPPER TROUGH CONTINUES TO DIG SOUTHEASTWARD. WITH CLEARING
SKIES AND THE COLD AIR MASS...WE SHOULD AGAIN GET DOWN TO THE -10
TO -20 RANGE TONIGHT. WINDS WILL DECREASE AS THE CENTER OF THE
HIGH MOVES DOWN INTO WESTERN ND...BUT THINK WE SHOULD HAVE ENOUGH
GRADIENT TO BRING WIND CHILLS DOWN TO ADVISORY LEVELS TONIGHT.
GIVEN THAT THERE IS A CURRENT HEADLINE FOR OUR NORTHEASTERN
COUNTIES AND WIND CHILL ADVISORIES ARE BECOMING A DIME A
DOZEN...WILL HOLD OFF ON ISSUING ONE FOR NOW. THE COLD HIGH
PRESSURE WILL REMAIN THROUGH THURSDAY WITH HIGHS JUST ABOVE ZERO.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 324 AM CST WED FEB 25 2015
THURSDAY NIGHT THROUGH FRIDAY NIGHT...NORTHWESTERLY FLOW ALOFT
CONTINUES WITH THE CENTER OF THE SFC HIGH FINALLY STARTING TO MOVE
SOUTH AND EAST. WIND CHILLS COULD AGAIN BE AN ISSUE THURSDAY NIGHT
INTO FRIDAY MORNING. THE SOUTHERLY WINDS WILL INCREASE MORE ON
FRIDAY AS HIGH PULLS FURTHER AWAY. TEMPS SHOULD GET UP TO AROUND
10 BY FRIDAY AFTERNOON UNDER THE LATE WINTER SUN BUT WILL STILL BE
WELL BELOW AVERAGE AND WILL FEEL PRETTY RAW WITH THE INCREASING
WINDS. WEAK WARM AIR ADVECTION AND WINDS KEEPING US MIXED WILL
ALLOW TEMPS FRIDAY NIGHT TO FALL ONLY SLIGHTLY BELOW ZERO INSTEAD
OF THE TEENS BELOW.
SATURDAY TO WEDNESDAY...MODELS IN GOOD AGREEMENT WITH THE EXTENDED
LEADING TO HIGH CONFIDENCE FOR MUCH OF THE WEEKEND AND FIRST PART OF
NEXT WEEK. DRY WEATHER WILL CONTINUE ACROSS THE NORTHERN PLAINS WITH
THE ONLY SLGHT CHC FOR -SN BEING TUESDAY INTO WEDNESDAY FOR THE
SOUTHERN AND EASTERN PORTIONS OF THE AREA. 500MB SPLIT FLOW
CONTINUES WITH WESTERN CONUS THROUGH AMPLIFYING INTO THE FIRST PART
OF NEXT WEEK THE 500MB SW TO NE ORIENTED TROUGH AXIS PUSHES ACROSS
THE FA ON TUESDAY...BRINGING THE -SN POTENTIAL. TEMPERATURES NEAR
SEASONAL NORMALS WITH HIGHS IN THE 20S SAT-TUE WITH POST FROPA COLD
FOR WEDNESDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 652 AM CST WED FEB 25 2015
LIGHT SNOW CONTINUES TO THE SOUTHWEST OF TAF SITES...WHICH ALL
HAVE VFR CIGS IF ANY AT ALL. CIGS OF 5000-10000 FT WILL REMAIN
OVER MUCH OF THE AREA THIS MORNING BEFORE THE SYSTEM PULLS FURTHER
SOUTH AND WE BEGIN TO CLEAR OUT FOR TONIGHT. NORTHEAST WINDS WILL
SHIFT TO THE NORTH TO NORTHWEST AND INCREASE A BIT...UP TO THE 15
TO 20 KT RANGE IN PLACES. HIGH PRESSURE BUILDING IN SHOULD ALLOW
THE WINDS TO DECREASE AFTER SUNSET.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...WIND CHILL ADVISORY UNTIL 10 AM CST THIS MORNING FOR MNZ005-006-
008-009.
&&
$$
UPDATE...JR
SHORT TERM...JR
LONG TERM...JR/JK
AVIATION...JR
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
324 AM CST WED FEB 25 2015
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 324 AM CST WED FEB 25 2015
SNOW THIS MORNING AND WIND CHILLS TONIGHT WILL BE THE PRIMARY
FORECAST CHALLENGE FOR THE SHORT TERM.
NORTHWESTERLY FLOW ALOFT CONTINUES WITH A WEAK REINFORCING
SHORTWAVE DIGGING THROUGH THE DAKOTAS. THE BAND OF SNOW HAS BEEN A
BIT FURTHER EAST THAN EXPECTED...AND VALLEY CITY HAS BEEN DOWN TO
2SM WITH LIGHT SNOW AND IT LOOKS LIKE GWINNER HAS FINALLY
SATURATED AND IS GETTING SOME SNOW AT THE SFC. THE BAND MATCHES UP
WITH THE 850-700MB FRONTOGENESIS FAIRLY WELL...AND THE NAM HAS
THAT AREA STARTING TO MOVE OFF TO THE SOUTH LATER THIS MORNING.
THAT SEEMS TO FIT PRETTY WELL WITH THE RAP AND HRRR WHICH HAVE THE
QPF PEAKING AROUND 10Z AND THEN TAPERING OFF 3 TO 4 HOURS LATER.
TIME HEIGHT PLOTS FOR OUR SOUTHWESTERN CWA HAVE A GOOD OMEGA
BULLSEYE IN THE GOOD DENDRITIC GROWTH ZONE UNTIL AROUND 12Z.
CONTINUED TREND OF CATEGORICAL POPS IN THE FAR WEST FOR EARLY THIS
MORNING...WITH SOME ADJUSTMENTS FOR CURRENT RADAR TRENDS. RAP PUTS
OUT NEARLY 3 INCHES IN FAR SOUTHERN SARGENT COUNTY...BUT THIS
SEEMS A BIT HIGH GIVEN HOW LONG IT HAS TAKEN OBS SITES TO
SATURATE. CONTINUED WITH 1 TO 2 INCHES IN THE FAR SOUTHWESTERN CWA.
THE PRECIP SHOULD TAPER OFF BY MID MORNING AND WE WILL SEE
DECREASING CLOUDS MOVE SOUTH AS ARCTIC HIGH PRESSURE BUILDS INTO
THE NORTHERN PLAINS. THE HIGH WILL CONTINUE INTO TONIGHT AS THE
MAIN UPPER TROUGH CONTINUES TO DIG SOUTHEASTWARD. WITH CLEARING
SKIES AND THE COLD AIR MASS...WE SHOULD AGAIN GET DOWN TO THE -10
TO -20 RANGE TONIGHT. WINDS WILL DECREASE AS THE CENTER OF THE
HIGH MOVES DOWN INTO WESTERN ND...BUT THINK WE SHOULD HAVE ENOUGH
GRADIENT TO BRING WIND CHILLS DOWN TO ADVISORY LEVELS TONIGHT.
GIVEN THAT THERE IS A CURRENT HEADLINE FOR OUR NORTHEASTERN
COUNTIES AND WIND CHILL ADVISORIES ARE BECOMING A DIME A
DOZEN...WILL HOLD OFF ON ISSUING ONE FOR NOW. THE COLD HIGH
PRESSURE WILL REMAIN THROUGH THURSDAY WITH HIGHS JUST ABOVE ZERO.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 324 AM CST WED FEB 25 2015
THURSDAY NIGHT THROUGH FRIDAY NIGHT...NORTHWESTERLY FLOW ALOFT
CONTINUES WITH THE CENTER OF THE SFC HIGH FINALLY STARTING TO MOVE
SOUTH AND EAST. WIND CHILLS COULD AGAIN BE AN ISSUE THURSDAY NIGHT
INTO FRIDAY MORNING. THE SOUTHERLY WINDS WILL INCREASE MORE ON
FRIDAY AS HIGH PULLS FURTHER AWAY. TEMPS SHOULD GET UP TO AROUND
10 BY FRIDAY AFTERNOON UNDER THE LATE WINTER SUN BUT WILL STILL BE
WELL BELOW AVERAGE AND WILL FEEL PRETTY RAW WITH THE INCREASING
WINDS. WEAK WARM AIR ADVECTION AND WINDS KEEPING US MIXED WILL
ALLOW TEMPS FRIDAY NIGHT TO FALL ONLY SLIGHTLY BELOW ZERO INSTEAD
OF THE TEENS BELOW.
SATURDAY TO WEDNESDAY...MODELS IN GOOD AGREEMENT WITH THE EXTENDED
LEADING TO HIGH CONFIDENCE FOR MUCH OF THE WEEKEND AND FIRST PART OF
NEXT WEEK. DRY WEATHER WILL CONTINUE ACROSS THE NORTHERN PLAINS WITH
THE ONLY SLGHT CHC FOR -SN BEING TUESDAY INTO WEDNESDAY FOR THE
SOUTHERN AND EASTERN PORTIONS OF THE AREA. 500MB SPLIT FLOW
CONTINUES WITH WESTERN CONUS THROUGH AMPLIFYING INTO THE FIRST PART
OF NEXT WEEK THE 500MB SW TO NE ORIENTED TROUGH AXIS PUSHES ACROSS
THE FA ON TUESDAY...BRINGING THE -SN POTENTIAL. TEMPERATURES NEAR
SEASONAL NORMALS WITH HIGHS IN THE 20S SAT-TUE WITH POST FROPA COLD
FOR WEDNESDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1150 PM CST TUE FEB 24 2015
SNOW BAND WILL AFFECT KDVL...BUT ONLY BRIEFLY THROUGH 09Z.
OTHERWISE...VFR CONDITIONS FOR THE TAF SITES WITH MVFR CONDITIONS
REMAINING TO THE WEST AND SOUTH.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...WIND CHILL ADVISORY UNTIL 10 AM CST THIS MORNING FOR MNZ005-006-
008-009.
&&
$$
SHORT TERM...JR
LONG TERM...JR/JK
AVIATION...TG
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1241 AM CST WED FEB 25 2015
.UPDATE...
ISSUED AT 1241 AM CST WED FEB 25 2015
STRONG EASTERLY OVERRUNNING FLOW...COUPLED WITH A MID LEVEL S/WV
MOVING SOUTHEAST ACROSS THE NORTHERN PLAINS AND SOME DIVERGENT
FLOW ALOFT IN THE WAKE OF A DEPARTING UPPER JET STREAK...CONTINUES
TO RESULT IN WIDESPREAD LIGHT SNOW ACROSS MUCH IF NOT ALL OF
WESTERN AND CENTRAL NORTH DAKOTA EARLY THIS MORNING. POPS WERE
INCREASED ACCORDINGLY BASED ON RADAR MOSAIC AND NEAR TERM HIGH-RES
MODEL OUTPUT. STILL EXPECTING AN INCH MAX AS FAR AS SNOWFALL
ACCUMULATIONS NOW THROUGH EARLY WED AFTERNOON. MOST AREAS WILL
RECEIVE LESS THAN AN INCH.
A FEW BREAKS IN THE MID/UPPER LEVEL CLOUD DECK HAS RESULTED IN
SOME LIGHT FREEZING RAIN/DRIZZLE SO EXTENDED THIS MENTION THROUGH
THE OVERNIGHT TILL AROUND 15Z BASED ON NAM/GFS RH PROFILES AND
TIME HEIGHT CROSS-SECTIONS. LATEST SPC MESOANALYSIS AND IR SAT
IMAGERY BOTH INDICATE THIS AS WELL.
OTHER FORECAST ELEMENTS ON TRACK WITH NO MAJOR EDITS WITH THIS
UPDATE.
UPDATE ISSUED AT 850 PM CST TUE FEB 24 2015
LATEST RADAR IS NOT VERY IMPRESSIVE COMPARED TO WHERE WE HAD OUR
GREATEST SNOW AMOUNTS. HEAVIEST PRECIPITATION THIS EVENING HAS
BEEN ASSOCIATED WITH THE SURFACE LOW AND INVERTED TROUGH OVER
EASTERN MONTANA. LATEST ITERATIONS OF THE RAP/HRRR KEEP THIS
PRECIPITATION CONFINED TO MAINLY SOUTHWEST AND FAR SOUTH CENTRAL
NORTH DAKOTA...PERHAPS SLIDING EAST OF THE MISSOURI RIVER OVER THE
FAR SOUTH CENTRAL...THROUGH AROUND 08-09 UTC. THEREAFTER QPF IS
VERY LIGHT IN NATURE ALONG THE BAROCLINIC ZONE OVER CENTRAL NORTH
DAKOTA. NOT MUCH CURRENTLY HAPPENING FROM THE NORTHWEST INTO THE
SOUTH CENTRAL PRESENTLY. LATEST RAP SOUNDINGS DO SUGGEST A DRY
LAYER ALOFT AND HAVE ADDED A MENTION OF PATCHY FREEZING DRIZZLE
THROUGH THE REMAINDER OF THIS EVENING. THIS SHOULD DISSIPATE AFTER
MIDNIGHT AS MOISTURE ALOFT INCREASES.
WE DID GET SOME SNOW DURING THE DAY WITH AROUND AN 1.5 INCHES
REPORTED AT WILLISTON. HOWEVER MOST OF WHAT FELL DURING THE DAY
MELTED DUE TO OUR WARM TEMPERATURES. LATEST NAM/RAP/HRRR INDICATE
PRECIPITATION TAPERING QUICKLY FROM NORTH TO SOUTH WEDNESDAY WITH
PRECIPITATION MOSTLY ENDED BY MIDDAY...EXCEPT PERHAPS ALONG THE
SOUTH DAKOTA BORDER. THEREFORE HAVE ADJUSTED SNOW AMOUNTS AND HAVE
NOT INCLUDED WHAT FELL DURING THE DAY. WITH THIS...WE ARE NOW
LOOKING AT SNOW TOTALS TONIGHT THROUGH EARLY AFTERNOON WEDNESDAY
OF MAINLY AN INCH OR LESS. WITH HIGHER AMOUNTS...UP TO 2 INCHES
OVER THE FAR SOUTH CENTRAL FROM SIOUX...SOUTHERN GRANT AND
SOUTHERN MORTON COUNTIES...EAST THROUGH SOUTHERN EMMONS AND INTO
DICKEY AND MCINTOSH COUNTIES. LESSER AMOUNTS ARE NOTED OVER THE
TURTLE MOUNTAINS INTO THE NORTHERN JAMES RIVER VALLEY...AND OVER
THE FAR SOUTHWEST.
UPDATE ISSUED AT 606 PM CST TUE FEB 24 2015
FRONTAL BOUNDARY REMAINS OVER NORTHEAST MONTANA INTO FAR SOUTHWEST
NORTH DAKOTA. CURRENT RADAR IMAGERY SHOWS SOME HIGHER
REFLECTIVITIES FROM WEST CENTRAL INTO SOUTHWEST NORTH DAKOTA. A
FEW LIGHTER REFLECTIVITIES WERE LOCATED OVER THE NORTH CENTRAL. IN
GENERAL THOUGH...A DECREASE OVER THE PAST FEW HOURS. HAVE ADJUSTED
POPS DOWN EARLY THIS EVENING FOR MANY AREAS. THINK SNOW WILL PICK
UP AGAIN LATER TONIGHT INTO THE OVERNIGHT HOURS AS THE SURFACE LOW
SLIDES ALONG THE FRONTAL ZONE AND PUSHES THE INVERTED SURFACE
TROUGH INTO SOUTHWEST NORTH DAKOTA. THIS WILL ENHANCE THE
BAROCLINIC ZONE OVER WESTERN AND CENTRAL NORTH DAKOTA. OTHERWISE
NO BIG CHANGES EARLY THIS EVENING.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 300 PM CST TUE FEB 24 2015
CURRENT SURFACE ANALYSIS PLACES PRIMARY LOW TO THE SOUTH OF JAMES
BAY WHILE SECONDARY LOW CONTINUES TO DEEPEN AND SLIDE SOUTH FROM
SOUTHWEST SASKATCHEWAN INTO NORTHEAST MONTANA. COLD FRONT CONTINUES
TO WORK SOUTH STRETCHING FROM EAST-CENTRAL SOUTH DAKOTA INTO FAR
SOUTHWEST NORTH DAKOTA. BEHIND THE FRONT...TEMPERATURES CONTINUE
TO EITHER HOLD STEADY OR SLOWLY DROP. UPPER LEVEL ANALYSIS PLACES
LOW OVER NORTHERN ONTARIO WITH SECONDARY LOW SLIDING FROM EASTERN
ARIZONA INTO NEW MEXICO...WHILE RIDGE REMAINS OFF THE PACIFIC
COAST. ACTIVE NORTHWEST FLOW REMAINS OVER OUR AREA. INITIAL ROUND
OF SNOW CONTINUES OVER PORTIONS OF THE AREA AFFILIATED WITH RIGHT
ENTRANCE REGION OF PASSING JET STREAK AND MODEST ISENTROPIC LIFT.
FOR THE REST OF THIS AFTERNOON INTO TONIGHT...AFOREMENTIONED JET
STREAK WILL CONTINUE TO PROGRESS OFF TO THE SOUTHEAST AND
ISENTROPIC LIFT STARTS TO WEAKEN WHICH MAY BRING A BRIEF BREAK IN
THE SNOW...THOUGH EXPECT ANOTHER ROUND OF ENHANCED SNOWFALL TONIGHT
AS SHORT WAVE OVER CENTRAL SASKATCHEWAN MAKES ITS APPROACH INTO
THE REGION. LATEST SUITE OF MODELS HAS DONE A BIT OF A SHIFT TO
THE EAST WHEN COMPARED TO PREVIOUS RUNS...SO HAVE PUSHED THE FOCUS
FOR HIGHER POPS AND SNOW AMOUNTS FURTHER TOWARDS CENTRAL NORTH
DAKOTA. COLD AIRMASS WILL CONTINUE ITS SHIFT INTO THE AREA WITH
LOWS MAINLY IN THE SINGLE DIGITS...AND BELOW ZERO READINGS OVER
PARTS OF NORTH CENTRAL.
ON WEDNESDAY...SNOW WILL SLOWLY SHIFT OFF TO THE SOUTH THROUGH THE
DAY WITH THE PROGRESSION WITH THE AFOREMENTIONED UPPER WAVE. COLD
AIRMASS WILL CONTINUE TO POUR INTO THE AREA BRINGING HIGH
TEMPERATURES CLOSE TO THE PREVIOUS NIGHTS LOWS.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 300 PM CST TUE FEB 24 2015
THE EXTENDED CONTINUES TO BE DOMINATED BY A BLOCKING RIDGE OVER
THE EASTERN PACIFIC AND THE RESULTING DOWNSTREAM COLD UPPER LOW
FROM CENTRAL AND EASTERN CANADA THOUGH THE SOUTHWEST US. THIS WILL
KEEP THE EXTENDED PERIOD COLD AND DRY.
WEDNESDAY NIGHT THROUGH FRIDAY: A 1044MB ARCTIC HIGH PRESSURE CENTER
OVER SOUTHERN SASKATCHEWAN WEDNESDAY EVENING WILL PUSH SOUTHEAST
TOWARDS THE NORTH DAKOTA BORDER. THE MODELS PLACE THE HIGH CENTER
OVER CENTRAL NORTH DAKOTA BY THURSDAY AFTERNOON/EVENING...AND INTO
EASTERN SOUTH DAKOTA BY DAYBREAK FRIDAY MORNING. LOWS WEDNESDAY
NIGHT AND THURSDAY NIGHT SHOULD RANGE FROM 5 BELOW TO 20 BELOW
ZERO...WITH HIGHS ON THURSDAY FROM ZERO TO 10 ABOVE. WIND CHILLS
WILL BE THE MAIN CONCERN DURING THIS PERIOD. WIND CHILLS 25 TO 40
BELOW WILL BE A HAZARD WEDNESDAY NIGHT INTO THURSDAY MORNING AND
AGAIN THURSDAY NIGHT INTO FRIDAY MORNING OVER MOST OF THE
REGION...WITH THE FAR SOUTHWEST ESCAPING THE COLDEST WIND CHILL
VALUES.
THE WEEKEND INTO MONDAY WILL BE COOL AND DRY AS THE PRECIPITATION
WILL BE LIMITED TO THE BAROCLINIC ZONES SURROUNDING THE NORTHERN
PLAINS LEAVING NORTH DAKOTA DRY. HIGHS SHOULD BE MAINLY IN THE TEENS
AND 20S...WITH LOWS FROM 5 BELOW TO 10 ABOVE ZERO OVER MUCH OF THE
AREA THIS WEEKEND. A SLIGHT MODERATION IS POSSIBLE MONDAY WITH HIGHS
IN THE 20S TO LOWER 30S...BUT THEN COOLER AGAIN FOR TUESDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1241 AM CST WED FEB 25 2015
A LOW PRESSURE SYSTEM WILL MOVE SOUTHEAST ACROSS THE WESTERN DAKOTAS
TONIGHT INTO WEDNESDAY MORNING. MVFR TO IFR CONDITIONS EXPECTED AT
KDIK TONIGHT AND WEDNESDAY MORNING IN PERIODS OF LIGHT SNOW AND FOG.
MAINLY MVFR TO LOW VFR CONDITIONS AT KBIS AND KISN TONIGHT AND
WEDNESDAY MORNING IN LIGHT SNOW. KMOT AND KJMS ARE EXPECTED TO
REMAIN MAINLY VFR BUT WITH PERIODS OF MVFR/IFR CEILINGS/VISIBILITIES
IN LIGHT SNOW TONIGHT. EASTERLY FLOW WILL SHIFT NORTHEAST AND THEN
NORTH WEDNESDAY WITH WINDS INCREASING FROM AROUND 10 KNOTS TONIGHT
TO 10 TO 20 KNOTS WEDNESDAY. EXPECT SKIES TO BECOME VFR AT ALL TAF
SITES WEDNESDAY AFTERNOON THROUGH WEDNESDAY NIGHT.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...NH
SHORT TERM...JJS
LONG TERM...JV
AVIATION...NH
AREA FORECAST DISCUSSION...UPDATED
NWS MORRISTOWN TN
1034 AM EST WED FEB 25 2015
.DISCUSSION...
THE FORECAST APPEARS ON TRACK...WITH NO INDICATIONS OF MAJOR
CHANGES BASED ON THE LATEST OBSERVED AND MODEL DATA. THE HRRR SEEMS
TO BE DOING WELL IN DEPICTING THE PRECIP OVER AL AND MS. SOME
EVAPORATION INTO A LOW LEVEL DRY LAYER WILL DELAY PRECIP AT THE
GROUND...WITH THE CHA AREA EXPECTED TO SEE SNOW BEGIN IN THE 20-22Z
WINDOW. STRONG VERTICAL ASCENT ASSOCIATED WITH AGEOSTROPHIC FORCING
COULD BRING A PERIOD OF HEAVY SNOW IN SOUTHERN AREAS AROUND 00Z.
EXPECT THAT TIMING AROUND KNOXVILLE AND OAK RIDGE WILL BE
22-00Z...WITH TRI-CITIES AND SW VA APPROXIMATELY BETWEEN 00Z-02Z.
THE WINDOW FOR HEAVY SNOW IS NOT OPEN FOR LONG...AS MIDLEVEL
MOISTURE IN THE DENDRITE GROWTH ZONE BEGINS TO DISAPPEAR IN THE
04-08Z TIME FRAME.
FORECAST SNOW AMOUNTS ARE IN LINE WITH THE LATEST SREF...BUT A
LITTLE LOW IN SOME SPOTS COMPARED TO THE LATEST NAM...WHICH SPREADS
3+ INCH AMOUNTS ALL THE WAY INTO THE PLATEAU. THE HRRR IS ON THE
OTHER END OF THE SPECTRUM...SHOWING VERY LITTLE SNOW WEST OF OAK
RIDGE. THE NAM IS AN OUTLIER...BUT IT IS NOTABLE THAT THERE IS A
CLUSTER OF SREF MEMBERS THAT SHOW SNOW ACCUMULATION SEVERAL INCHES
ABOVE THE SREF MEAN.
WILL KEEP SNOW AMOUNTS AND THE WARNING/ADVISORY AREAS UNCHANGED
FOR THE UPDATE. TEMPERATURES WILL NEED SOME DOWNWARD ADJUSTMENTS
AS OBS ARE RUNNING LOWER THAN FORECAST IN SEVERAL SPOTS.
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...WINTER STORM WARNING FROM 4 PM THIS AFTERNOON TO 7 AM EST
THURSDAY FOR CHEROKEE-CLAY.
TN...WINTER STORM WARNING FROM 4 PM THIS AFTERNOON TO 7 AM EST
THURSDAY FOR BLOUNT SMOKY MOUNTAINS-COCKE SMOKY MOUNTAINS-
JOHNSON-SEVIER SMOKY MOUNTAINS-SOUTHEAST CARTER-SOUTHEAST
GREENE-SOUTHEAST MONROE-UNICOI.
WINTER WEATHER ADVISORY FROM 4 PM EST /3 PM CST/ THIS AFTERNOON
TO 7 AM EST /6 AM CST/ THURSDAY FOR ANDERSON-BLEDSOE-
CAMPBELL-CLAIBORNE-GRAINGER-HAMBLEN-HANCOCK-HAWKINS-
JEFFERSON-KNOX-LOUDON-MORGAN-NW BLOUNT-NORTH SEVIER-
NORTHWEST CARTER-NORTHWEST COCKE-NORTHWEST GREENE-RHEA-
ROANE-SCOTT TN-SULLIVAN-UNION-WASHINGTON TN.
WINTER STORM WARNING UNTIL 7 AM EST /6 AM CST/ THURSDAY FOR
BRADLEY-EAST POLK-HAMILTON-MARION-MCMINN-MEIGS-NORTHWEST
MONROE-SEQUATCHIE-WEST POLK.
VA...WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO 7 AM EST
THURSDAY FOR LEE-RUSSELL-SCOTT-WASHINGTON-WISE.
&&
$$
DGS
AREA FORECAST DISCUSSION
NWS EL PASO TX/SANTA TERESA NM
353 AM MST WED FEB 25 2015
.SYNOPSIS...
UPPER LOW WHICH BROUGHT WIND AND SHOWERS TO THE AREA TUESDAY HAS NOW
MOVED EAST OF THE AREA TO BE REPLACED BY DRIER NORTHWEST FLOW.
TEMPERATURES TODAY WILL REMAIN NEAR NORMAL. ANOTHER COLD FRONT MOVES
IN FROM THE EAST ON THURSDAY TO GIVE US A COUPLE OF COOL DAYS. THE
FRONT COULD ALSO PRODUCE SOME LIGHT SNOW OVER THE SACRAMENTO
MOUNTAINS. AN UPPER LEVEL LOW WILL DROP TO THE GREAT BASIN SATURDAY
AND THEN OVER ARIZONA ON MONDAY. THIS WILL BRING MORE MOISTURE TO
THE AREA WITH A CHANCE OF SHOWERS...MAINLY SATURDAY THROUGH TUESDAY.
TEMPERATURES WILL WARM BACK TO AROUND NORMAL.
&&
.DISCUSSION...
UPPER LOW WHICH BROUGHT US OUR WIND AND SHOWERS ON TUESDAY HAS NOW
MOVED OVER THE TEXAS PANHANDLE. VERY FEW CLOUDS LEFT OTHER THAN A
FEW SCRAPS OVER HUDSPETH COUNTY. AREAS WEST OF THE RIO GRANDE VALLEY
HAVE HAD GOOD RADIATIONAL COOLING FOR SEVERAL HOURS. HRRR SHOWS
WINDS AND DEWPOINT DEPRESSIONS CONDUCIVE TO SOME FOG OVER THE NEXT
SEVERAL HOURS SO MENTIONED PATCHY FOG/FREEZING FOG FOR THE LOWLAND
ZONES WEST OF EL PASO THIS MORNING. BELIEVE WEST TEXAS ZONES HAVE
NOT HAD AS LONG OF RADIATIONAL COOLING SO LEFT FOG MENTION OUT OF
THOSE ZONES.
NEXT FEATURE TO WATCH IS THE BACKDOOR COLD FRONT PUSHING IN ON
THURSDAY IN RESPONSE TO A SHORT WAVE MOVING DOWN IN THE NORTHWEST
FLOW ALOFT. SOME EASTERLY SURGE MOVES IN ALREADY LATE TONIGHT BUT
THE MAIN COLD FRONT REACHES THE SACRAMENTO MOUNTAINS THURSDAY MID
MORNING. EXPECT SOME UPSLOPE LIGHT SNOW WITH THIS OVER THE SACS.
TEMPERATURES WILL COOL MOST OF THE CWA AS THE FRONT REACHES WEST TO
AT LEAST THE CONT DIVIDE. BOTH GFS/NAM SHOW VORT CENTER DROPPING
DOWN OVER CENTRAL NEW MEXICO FRIDAY AFTERNOON AND PERHAPS ENHANCING
MORE SIGNIFICANT SNOWFALL FOR THE SACS...THOUGH LIKELY ADVISORY TYPE
SNOW ACCUMULATIONS AT BEST. TEMPS THURSDAY/FRIDAY TO FALL BACK BELOW
NORMAL.
WEEKEND AND FIRST PART OF NEXT WEEK STILL LOOKING UNSETTLED AND
MODELS NOT EXACTLY DOING BANG UP JOB OF REACHING CONSENSUS. GFS FOR
SEVERAL RUNS NOW HAS BEEN QUITE BULLISH ON DROPPING NEXT POSITIVELY
TILTED TROUGH SOUTHWARD AND CLOSING LOW OFF OVER THE GREAT
BASIN...EVENTUALLY BRING LOW OVER ARIZONA AND TAPPING INTO SOME SUB
TROPICAL MOISTURE. ECMWF HAS BEEN MORE BEARISH...BARELY CLOSING OFF
A LOW IF AT ALL...AND MOVING SYSTEM ACROSS NEW MEXICO AS AN OPEN
TROUGH. QUICK LOOK AT 06Z GFS RUN NOW SHOWS IT STARTING TO RESEMBLE
THE ECMWF. GRIDS/FORECAST FOR NOW GOING A BIT MORE WITH THE BULLISH
GFS SOLUTION. MOISTURE TAP AND LOW SHOULD START PRODUCING SOME
SHOWERS WESTERN ZONES ON SATURDAY AND SLOWLY SPREADING THE SHOWERS
EASTWARD...TO INCLUDE THE EASTERN ZONES BY SUNDAY NIGHT OR MONDAY.
SNOW LEVELS START OUT HIGH...AT 8000 FT OR HIGHER BUT GRADUALLY
LOWER SUNDAY NIGHT AND MONDAY AS PACIFIC COLD FRONT APPROACHES. GFS
CONTINUES TO SHOW HEAVY SNOW POTENTIAL FOR THE GILA/BLACK RANGE
MOUNTAINS. HOPE MODELS CONVERGE ON THE SOLUTION SOON!
&&
.AVIATION...VALID 25/12Z-26/12Z...
VFR EXPECTED AT ALL TERMINALS THRU THE PERIOD. P6SM SKC INITIALLY
WITH FEW-SCT250 EXPECTED AFTER 00Z. SFC WINDS PRIMARILY FROM THE
WEST AT SPEEDS OF 12 KTS OR LESS WITH GUSTS 15-20 KTS POSSIBLE
BETWEEN 18Z AND 00Z.
&&
.FIRE WEATHER...
DRIER NORTHWEST FLOW HAS SETTLED ACROSS THE REGION AS AN UPPER LEVEL
LOW CONTINUES TO MOVE OFF TO THE EAST. EXPECT MOSTLY CLEAR SKIES
TODAY WITH AFTERNOON TEMPS RETURNING TO NEAR NORMAL. THIS WILL
RESULT IN MIN RH VALUES DROPPING TO BETWEEN 15 AND 20 PERCENT FOR
MOST LOWLAND LOCATIONS WITH SLIGHTLY HIGHER READINGS ACROSS THE
HIGHER TERRAIN. 20 FOOT WINDS WILL PICK UP AGAIN FROM THE WEST
DURING THE AFTERNOON HELPING LIFT VENT RATES INTO THE GOOD TO VERY
GOOD RANGE ACROSS THE REGION.
ANOTHER PAIR OF WEAK UPPER DISTURBANCES WILL CLIP THE AREA THURSDAY
AND FRIDAY WITH ANOTHER BACK DOOR COLD FRONT TO MOVING INTO THE
AREA EARLY THURSDAY. WHILE THE BEST CHANCES FOR WETTING PRECIP WILL
REMAIN TO OUR NORTH THERE IS A SLIGHT CHANCE FOR SOME RAIN AND SNOW
OVER THE SACRAMENTO MOUNTAINS DURING THIS TIME FRAME. WE WILL ALSO
SEE MIN RH VALUES INCREASE BY 15 TO 20 PERCENT ACROSS THE REGION AS
EASTERLY BREEZES BRING IN COOLER AIR AT THE SURFACE. THIS WILL BE
FOLLOWED BY ANOTHER WARM UP OVER THE WEEKEND BEFORE A STRONGER STORM
DELIVERS MORE MORE WIND AND A BETTER CHANCE FOR WETTING PRECIP FOR
THE EARLY PART OF NEXT WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
EL PASO 63 39 58 33 53 / 0 0 0 0 0
SIERRA BLANCA 60 34 49 25 47 / 0 0 0 0 0
LAS CRUCES 62 34 56 31 53 / 0 0 0 0 0
ALAMOGORDO 55 32 50 30 48 / 0 0 0 10 0
CLOUDCROFT 40 20 35 22 32 / 0 0 20 30 10
TRUTH OR CONSEQUENCES 60 34 54 32 50 / 0 0 0 0 0
SILVER CITY 53 32 53 34 49 / 0 0 0 0 0
DEMING 62 32 59 30 57 / 0 0 0 0 0
LORDSBURG 61 31 60 30 58 / 0 0 0 0 0
WEST EL PASO METRO 63 38 57 35 53 / 0 0 0 0 0
DELL CITY 58 31 51 23 44 / 0 0 0 0 10
FORT HANCOCK 64 38 57 33 52 / 0 0 0 0 0
LOMA LINDA 55 35 48 31 44 / 0 0 0 0 0
FABENS 63 36 57 31 54 / 0 0 0 0 0
SANTA TERESA 63 35 56 31 53 / 0 0 0 0 0
WHITE SANDS HQ 60 36 53 31 49 / 0 0 0 0 0
JORNADA RANGE 60 28 54 26 51 / 0 0 0 0 0
HATCH 63 32 58 29 55 / 0 0 0 0 0
COLUMBUS 62 37 60 35 58 / 0 0 0 0 0
OROGRANDE 57 36 52 31 47 / 0 0 0 0 0
MAYHILL 47 24 35 22 32 / 0 0 20 30 20
MESCALERO 45 24 39 23 36 / 0 0 20 30 20
TIMBERON 46 25 39 24 34 / 0 0 10 20 10
WINSTON 52 28 49 32 44 / 0 0 0 10 0
HILLSBORO 57 34 52 34 48 / 0 0 0 0 0
SPACEPORT 60 30 55 28 51 / 0 0 0 0 0
LAKE ROBERTS 52 28 51 32 47 / 0 0 0 0 0
HURLEY 54 32 54 31 50 / 0 0 0 0 0
CLIFF 58 22 58 25 56 / 0 0 0 0 0
MULE CREEK 55 19 55 24 51 / 0 0 0 0 0
FAYWOOD 55 34 54 33 49 / 0 0 0 0 0
ANIMAS 64 33 63 31 60 / 0 0 0 0 0
HACHITA 63 31 62 29 59 / 0 0 0 0 0
ANTELOPE WELLS 65 32 65 32 62 / 0 0 0 0 0
CLOVERDALE 61 34 61 38 58 / 0 0 0 0 0
&&
.EPZ WATCHES/WARNINGS/ADVISORIES...
NM...NONE.
TX...NONE.
&&
$$
HEFNER/LANEY
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
306 PM CST WED FEB 25 2015
.TONIGHT - CONFIDENCE...MEDIUM
SNOW CONTINUES TO SLOWLY SHIFT EASTWARD THROUGH SRN WI OVERCOMING
THE DRY LOW LAYERS THAT WERE EVIDENT ON 12Z GRB SOUNDINGS. WITH THE
SATURATION HAS COME VSBYS DOWN TO 1/2 TO 3/4SM AT TIMES...ESP SW OF
KMSN. RADAR ANIMATION CONTINUES TO SUPPORT THE MODEL TRENDS OF
KEEPING BEST ACCUMS ALONG AND SOUTH OF I-94 CORRIDOR WITH THE
SYSTEMS BEST ACCUMS MISSING US ACROSS NORTHERN ILLINOIS. SO WILL
HAVE HIGHEST POPS AND ACCUMS IN THE SOUTHERN COUNTIES. THE OTHER
CONSIDERATION IS THE LAKE EFFECT POTENTIAL. TERMINAL DOPPLER HAS
BEEN SHOWING THE BAND HOLDING OFFSHORE THOUGH RAP SOUNDINGS DO SHOW
ONSHORE COMPONENT WITH DELTA T VALUES OF AROUND 21. EQUILIBRIUM
LEVELS ALSO PUSH 6K FEET. HAVE BUMPED UP SOME AMOUNTS A BIT ESP FROM
SE MKE CNTY THROUGH ERN RAC/ENW COUNTIES. WHILE ICE IS EVIDENT
THERE ARE ENOUGH BREAKS/SLUSHINESS TO ALLOW THE NECESSARY
INSTABILITY TO BE REALIZED FOR THE LAKE EFFECT. SO OVERALL 1-2 OF
SYSTEM SNOW FOR MAINLY SRN HALF OF THE CWA WITH SOME ISOLD 3 INCH
AMOUNTS ADJACENT TO THE LAKE SOUTH OF KMKE TO WI/IL BORDER KENW DUE
TO ADDED INFLUENCE OF LAKE EFFECT.
.THURSDAY - CONFIDENCE...MEDIUM
STILL SEEING SOME LINGERING ONSHORE COMPONENT DURING THE MORNING HOURS
SO THE GFS/NAM IDEA OF HANGING ONTO SOME LES POTENTIAL SEEMS REASONABLE.
ENOUGH NNW FETCH ESTABLISHED BY MIDDAY AND INTO THE AFTERNOON HOURS TO
REMOVE LES FROM GRIDS. 850 THERMAL TROUGH WILL BE IN PLACE WITH 925
TEMPS -17C TO -19C. SO MUCH BELOW NORMAL TEMPS EXPECTED WITH HIGHS UPPER
SINGLE DIGITS/LOW TEENS.
.SHORT TERM...FRIDAY THROUGH SATURDAY NIGHT...FORECAST CONFIDENCE
IS MEDIUM.
HIGH PRESSURE MOVES INTO THE REGION FRIDAY AND WINDS WILL BACK
FROM A MORE NORTHERLY DIRECTION TO THE NORTHWEST AND WEST BY
FRIDAY AFTERNOON. HIGHS FRIDAY WILL GENERALLY BE BETWEEN 10 AND 15.
THIS AREA OF HIGH PRESSURE SHOULD KEEP CONDITIONS QUIET THROUGH
THE DAY SATURDAY.
.LONG TERM...SUNDAY THROUGH WEDNESDAY...FORECAST CONFIDENCE IS
MEDIUM.
ECMWF IS PROGGING A POTENT 140KT 250 MB JET STREAK TO TRANSLATE
INTO THE REGION EARLY SUNDAY. SOUTHERN WISCONSIN WILL BE IN THE
LEFT EXIT REGION WITH SOME ASSOCIATED UPPER LEVEL DIVERGENCE. THIS
ALONG WITH A 500 MB SHORTWAVE DISTURBANCE LOOKS TO BRING A SYSTEM
INTO THE REGION FROM THE SOUTHWEST. THE GFS LOOKS TO BE MORE
BULLISH WITH THE 500 MB ENERGY THAN THE ECMWF ACCORDING TO THE
LATEST RUNS. 850 MB WARM AIR ADVECTION AND SOUTHERLY WINDS WILL
HELP BRING IN MOIST LOW LEVEL AIR AS WELL. THE BULK OF THE QPF
AMOUNTS LOOK TO STAY FURTHER SOUTH...OUT OF OUR FORECAST
AREA...BUT NOT BY MUCH. ALSO...THE ECMWF IS SLIGHTLY FASTER THAN
THE GFS REGARDING THE ONSET OF THE PRECIPITATION BY A FEW HOURS.
STILL SOME UNCERTAINTY AS TO THE LOCATION OF THE MAIN QPF AXIS.
ANOTHER SHOT OF COLD AIR ALONG WITH SOME NORTHWEST WINDS AS HIGH
PRESSURE RETURNS TO THE REGION MONDAY ONCE THE SUNDAY SYSTEM
MOVES OUT.
ANOTHER SYSTEM LOOKS TO MOVE INTO THE REGION FOR TUESDAY AS
ANOTHER PULSE OF 500 MB POSITIVE VORTICITY ENERGY TRANSLATES INTO
THE REGION...ALONG WITH BEING IN THE RIGHT ENTRANCE REGION OF A
STRONG 180KT 250 MB JET STREAK AND UPPER LEVEL DIVERGENCE. THERE
IS STILL MUCH UNCERTAINTY WITH THIS PARTICULAR EVENT. CURRENT SNOW
ACCUMULATIONS COULD BE BETWEEN 5 AND 6 INCHES ACROSS THE FORECAST
AREA. AT THE MOMENT...THE TIMING OF THE BULK OF THE SNOW WILL BE
DURING THE DAY TUESDAY. WE WILL CONTINUE TO MONITOR THE
PRECIPITATION TIMING AND AMOUNTS.
&&
.AVIATION/00Z TAFS/...WATER VAPOR SHOWS SHORTWAVE RIDING EAST
FROM IA. MEANWHILE SURFACE LOW DROPPING SE INTO ERN KS/WRN MO.
MODELS IN GOOD AGREEMENT IN SPREADING SNOW ACROSS REMAINDER OF SE
WI THIS AFTN AND EVE WITH ONSHORE COMPONENT LEADING TO SOME LAKE
EFFECT SNOWS AS WELL. SO EXPECTING SOME IFR CIGS AND PERHAPS SOME
LIFR VSBYS...BUT MOSTLY IFR VSBYS. LAKE EFFECT WRAPS UP THURSDAY
MORNING. SO OVERALL 1-2 OF SYSTEM SNOW FOR MAINLY SRN HALF OF THE
CWA WITH SOME ISOLD 3 INCH AMOUNTS NEAR LAKE MI DUE TO ADDED
INFLUENCE OF LAKE EFFECT.
&&
.MARINE...WIND GUSTS WL GET CLOSE TO SMALL CRAFT ADVY FOR A TIME
TONIGHT AS PRESSURE GRADIENT TIGHTENS DUE TO LOW PRESSURE PASSING
WELL SOUTH OF THE AREA.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
TONIGHT/THURSDAY AND AVIATION/MARINE...COLLAR
THURSDAY NIGHT THROUGH WEDNESDAY...JTS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
522 AM CST WED FEB 25 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 320 AM CST WED FEB 25 2015
MAIN FCST CONCERNS THIS PERIOD...SNOW CHANCES/AMOUNTS/NEEDED
HEADLINES ACROSS THE SOUTHWEST SIDE OF THE FCST AREA TODAY INTO
THIS EVENING...LOWS/WIND CHILLS LATER TONIGHT.
06Z DATA ANALYSIS HAD A WEAK RIDGE OF HIGH PRESSURE FROM MAN TO
IA/IL AND LOW PRESSURE DEEPENING INTO WESTERN SD. SHORTWAVE ENERGY
OF CONCERN FOR TODAY COULD BE SEEN IN WV IMAGERY DROPPING SOUTHEAST
ACROSS SOUTHERN SASKAT/ALB. SKIES REMAINED GENERALLY CLEAR ACROSS WI
WHILE CLOUDS AHEAD OF THE LOW/SHORTWAVE WERE QUICKLY SPREADING
ACROSS IA/MN. INCREASING FORCING/LIFT AHEAD OF THE LOW/SHORTWAVE WAS
PRODUCING AND INCREASING AREA OF SNOW ACROSS CENTRAL/SOUTHERN ND AND
EASTERN SD...HEADING SOUTHEAST TOWARD THE FCST AREA.
25.00Z MODELS INITIALIZED WELL...EXCEPT GFS ABOUT 5F TOO HIGH ON SFC
DEW POINTS ACROSS MUCH OF MN/IA/WI. MODELS OFFERING A TIGHTENING AND
STRONGER CONSENSUS AS THE SASKAT/ALB SHORTWAVE ENERGY DIVES
SOUTHEAST TOWARD IA TODAY THEN THIS ENERGY AND A SECONDARY NORTHERN
STREAM WAVE CARVE OUT RATHER STRONG MID LEVEL TROUGHING OVER THE
UPPER MIDWEST TONIGHT. SOME DETAIL DIFFERENCES WITH THE SHORTWAVE
ENERGY TODAY BUT END RESULT IS A STRONGER ROUND OF FORCING/LIFT TO
SPREAD ACROSS THE SOUTHWEST HALF OF THE REGION TODAY INTO THIS
EVENING. SHORT-TERM FCST CONFIDENCE IS GOOD THIS CYCLE.
FOR THE SHORT TERM...STRONGER TREND OF THE MODELS SPREADS A STRONGER
ROUND OF LOWER LEVEL THERMO-DYNAMIC FORCING WITH RATHER IMPRESSIVE
850-700MB FN/QG/QN CONVERGENCE/LIFT TO NOW CLIP THE SOUTHWEST END OF
THE FCST AREA TODAY. THIS UNDER FAVORABLE DIVERGENCE ALOFT AHEAD OF
THE SHORTWAVE TROUGH AND RIGHT ENTRANCE REGION OF A 300MB JET MAX
OVER THE GREAT LAKES. MODEL SOUNDINGS SHOWING A RATHER DEEP
DENDRITIC GROWTH ZONE FROM THE SFC-600MB OVER MUCH OF THE FCST AREA
LATER THIS MORNING AND AFTERNOON WHEN THE MAX FORCING/LIFT COME
ACROSS. QUESTION REMAINS NORTHEASTWARD EXTENT OF LOWER LEVEL
SATURATION AS INITIALLY A DRY SFC-700MB AIRMASS IS IN PLACE ACROSS
THE FCST AREA. WITH THE STRONGER LIFT AND NORTHWARD SHIFT OF THE
MODEL FORCING...CONSENSUS NOW SATURATES THE COLUMN ACROSS ROUGHLY
THE SOUTHWEST 2/3 OF THE FCST AREA TODAY INTO THIS EVENING...WITH
WHAT LOOKS TO BE SOME HIGH SNOW-WATER RATIOS /AROUND 20 TO 1/ OVER
THE SOUTHWEST END OF THE FCST AREA. SEVERAL OF THE HIGH-RES MODELS
NOW PRODUCE A SWATH OF 4 TO AS MUCH AS 12 INCHES OF SNOW ACROSS
SOUTHWEST MN TO EASTERN IA. HAVE RAISED SNOW CHANCES TO 70-100
PERCENT AND AMOUNTS ACROSS THE SOUTHWEST 2/3 OF THE FCST AREA FOR
TODAY INTO THIS EVENING. WITH THE CONSENSUS SHIFT NORTH AND HIGHER
SNOW AMOUNTS WILL ISSUE A WINTER WEATHER ADVISORY FOR MUCH OF
NORTHEAST IA FOR 15Z-03Z. DAY CREW WILL HAVE TO KEEP A CLOSE WATCH
ON EVOLUTION OF THE PRECIP/SNOW TRENDS ON WSR-88D/S. IF STRONGER/
MORE NORTH OF THE HIGH-RES WRF MODELS ARE CORRECT...ADVISORY MAY
HAVE TO BE EXPANDED EVEN FURTHER NORTH WITH POTENTIAL WINTER STORM
WARNING ALONG/SOUTH OF A ST. ANSGAR TO KOLZ IA LINE.
ANOTHER ROUND OF LOW LEVEL COLD ADVECTION SPREADS ACROSS THE AREA
TONIGHT WITH 925MB TEMPS IN THE -18C TO -22C RANGE BY 12Z THU. LOWS
HEAD TO NEAR/BELOW ZERO BUT SFC WINDS ON THE LIGHTER SIDE WITH A
WEAKER PRESSURE GRADIENT OVER THE AREA. ANY NEED FOR A WIND CHILL
ADVISORY LATE TONIGHT INTO THU MORNING APPEARS MARGINAL AT THIS
TIME WITH MINIMUM WIND CHILLS IN THE -15 TO AROUND -20. WILL LEAVE
ANY WIND CHILL ADVISORY DECISIONS TO DAY CREW. USED A BLEND OF THE
GUIDANCE HIGHS/LOWS FOR TODAY/TONIGHT.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 320 AM CST WED FEB 25 2015
MAIN FCST CONCERNS FOR THU THRU FRI NIGHT...CONTINUED COLD AND WELL
BELOW NORMAL TEMPERATURES.
25.00Z MODELS IN GOOD AGREEMENT FOR COLD MID LEVEL TROUGHING TO BE
OVER THE UPPER MIDWEST FOR THU THRU FRI NIGHT. HGTS PROGGED TO
SLOWLY RISE THRU THE PERIOD...BUT CONSENSUS IS FOR CAN/ARCTIC SFC
HIGH PRESSURE TO BE OVER THE REGION THIS PERIOD. FCST CONFIDENCE FOR
THIS PERIOD IS GOOD THIS CYCLE.
THU THRU FRI NIGHT CONTINUES TREND AS A COLD...DRY PERIOD AS THE
CENTER OF CAN/ARCTIC HIGH PRESSURE NEAR THE SASKAT/ND BORDER AT 12Z
THU DRIFTS SOUTHEAST TO OH VALLEY THRU 12Z SAT. PRESSURE GRADIENT IS
GENERALLY WEAK OVER THE AREA THRU THE PERIOD FOR LIGHTER WINDS. SOME
OF THE WEAKER/LIGHTER WINDS OVER THE AREA THU NIGHT WITH THE RIDGE
AXIS NEARBY. OVER FRESH SNOW COVER...ESPECIALLY THE SOUTHWEST 1/2 OF
THE FCST AREA...LOWS THU NIGHT TRENDING TO BE MOSTLY IN THE -10F TO
-15F RANGE...WITH SOME -15F TO -25F LOWS IN THE LOW LAYING AREAS
WHERE WINDS DECOUPLE/GO CALM. SLOW WARMUP FRI/FRI NIGHT AS THE
COLDEST CORE OF 925-850MB AIR SHIFTS SOUTHEAST OF THE FCST AREA.
WITH LITTLE CHANGE OF THE BOUNDARY LAYER AIRMASS AND LIGHT WINDS...
TEMPERATURES FRI/FRI NIGHT LOOKING TO REMAIN AROUND 20 DEGREES BELOW
NORMAL. USED A BLEND OF THE GUIDANCE HIGHS/LOWS FOR THU/FRI/FRI
NIGHT WHILE TRENDING TOWARD COLDER OF GUIDANCE FOR LOWS THU NIGHT.
FOR SATURDAY THRU TUESDAY...DAYS 4 TO 7...
MAIN FCST CONCERNS THIS PERIOD...SNOW CHANCES SAT NIGHT/SUN AND
AGAIN MON NIGHT/TUE...TEMPERATURES.
25.00Z MEDIUM RANGE MODEL RUNS CONTINUE TO ADVERTISE A PATTERN
CHANGE TOWARD MORE WESTERN CONUS TROUGHING AND RISING HGTS OVER
EASTERN NOAM IN THE SAT THRU TUE PERIOD. RATHER TIGHT MODEL
CONSENSUS ON THE DETAILS FOR SAT INTO SUN...BUT SOME SLIPPAGE OF RUN-
TO-RUN CONSISTENCY BY SUNDAY. REASONABLE CONSENSUS ON THE LONGWAVE
DETAILS OF STRONGER WESTERN NOAM TROUGHING EARLY NEXT WEEK BUT
PLENTY OF DETAIL DIFFERENCES ON TIMING/STRENGTH OF SHORTWAVES THRU
THIS FLOW. OVERALL FCST CONFIDENCE IS AVERAGE TO GOOD SAT/SUN THEN
AVERAGE TO BELOW FOR MON/TUE.
FIRST THING THE PATTERN SHIFT DOES IS ALLOW FOR MORE WESTERLY FLOW
INTO THE REGION AND THE ARCTIC AIRMASS TO BE PUSHED OUT OF THE
REGION. TEMP FOR THE WEEKEND INTO EARLY NEXT WEEK LOOK TO WARM MORE
INTO THE 5F TO 10F BELOW NORMAL RANGE VS. THE 20 TO 30 DEGREES BELOW
NORMAL THAT IS HAS BEEN MUCH OF THE PAST 2 WEEKS. TREND IS TOWARD
MORE OF A NORTHERN-SOUTHERN STREAM SPLIT FLOW OVER THE AREA FOR THE
WEEKEND...WITH THE CENTRAL/NORTHERN PARTS OF THE REGION MORE UNDER
THE NORTHERN STREAM. WHAT APPEARED LIKE IT WOULD BE A STORM SYSTEM
TO IMPACT THE FCST AREA SAT NIGHT/SUN CONTINUES TO SHIFT SOUTHWARD
WITH MORE DOMINANCE OF THE NORTHERN STREAM OVER THE AREA. SOME
RESIDUAL SMALL -SN CHANCES SAT/NIGHT SUN REMAIN AND THESE OKAY FOR
NOW BUT AGAIN MORE SIGNIFICANT ACCUMULATING SNOW THESE PERIODS HAS
TRENDED INTO IL/SOUTHERN IA. MODIFIED PACIFIC/CAN HIGH STILL SLATED
TO DRIFT ACROSS THE REGION SUN NIGHT MON. SIGNAL FOR A STRONGER
PIECE OF ENERGY TO LIFT OUT OF THE WESTERN TROUGH AND IMPACT THE
UPPER MIDWEST MON NIGHT/TUE. RUN-TO-RUN CONSISTENCY ON THIS DAY 6 TO
7 FEATURE IS WEAK YET...BUT TRENDS OF THE 25.00Z GFS/ECMWF WOULD
SPREAD A CHANCE OF ACCUMULATING SNOWS ACROSS THE AREA MON NIGHT/TUE.
FOR NOW STAYED WITH THE MODEL/ENSEMBLE CONSENSUS THESE PERIODS.
MODEL/ENSEMBLE CONSENSUS OF HIGHS/LOWS FOR SAT THRU MON ALSO LOOKS
GOOD FOR NOW.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 522 AM CST WED FEB 25 2015
REGIONAL RADARS INDICATE AN AREA OF LIGHT SNOW WAS ADVANCING EAST
ACROSS SOUTHERN MINNESOTA IN ASSOCIATION WITH A SURFACE LOW OVER
NORTHEAST NEBRASKA. ALL THIS ACTIVITY WAS BEING DRIVING BY A SHORT
WAVE TROUGH OVER WESTERN SOUTH DAKOTA. THE MODEL TRENDS HAVE BEEN
FOR THIS SYSTEM TO COME A LITTLE FARTHER NORTH CAUSING THE SNOW
BAND TO SHIFT TO THE NORTH AS WELL. THE 25.06Z NAM SUGGESTS THE
SURFACE LOW WILL TRACK INTO SOUTHERN IOWA TODAY WITH THE SNOW BAND
EXTENDING UP INTO SOUTHERN MINNESOTA AND WISCONSIN. BASED ON THE
TRENDS SHOWN BY THE NAM AND THE 25.10Z RAP AND HRRR...EXPECT THE
LIGHT SNOW TO MOVE INTO BOTH TAF SITES OVER THE LAST HALF OF THE
MORNING AND BASED ON UP STREAM OBSERVATIONS...THE VISIBILITY
SHOULD QUICKLY GO DOWN TO IFR WITH THE CEILINGS COMING DOWN TO
MVFR. WITH THE RAPID MOVEMENT OF THIS SYSTEM...THE SNOW SHOULD
START TO MOVE OUT OF KRST BY MID AFTERNOON AND AROUND SUNSET FOR
KLSE. A SHORT PERIOD OF MVFR VISIBILITY EXPECTED ON THE BACK EDGE
OF THE SNOW BEFORE IT COMPLETELY ENDS...HOWEVER...ENOUGH LOW LEVEL
MOISTURE TO KEEP THE CEILINGS MVFR UNTIL THE OVERNIGHT HOURS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...WINTER WEATHER ADVISORY FROM 9 AM THIS MORNING TO 9 PM CST THIS
EVENING FOR IAZ008-009-018-019-029-030.
&&
$$
SHORT TERM...RRS
LONG TERM....RRS
AVIATION...04
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1156 PM CST TUE FEB 24 2015
UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND WEDNESDAY
ISSUED AT 238 PM CST TUE FEB 24 2015
THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW AN ARCTIC
COLD FRONT STRETCHING FROM AROUND WAUTOMA TO MARINETTE AND MOVING
EAST EARLY THIS AFTERNOON. SNOW SHOWERS DEVELOPED AHEAD OF THE
FRONT EARLIER TODAY AND LOCALLY DROPPED VSBYS TO A QUARTER OF A
MILE. THESE SNOW SHOWERS ARE NOW ENTERING LAKE MICHIGAN. OTHER
WEAKER SNOW SHOWERS EXIST RIGHT BEHIND THE FRONT. EXCEPT FOR THE
SNOW BELT...THESE SNOW SHOWERS SHOULD EXIT BY THE START OF THE
EVENING. WINDS ARE BECOMING STRONG AND GUSTY BEHIND THE FRONT WITH
SOME OBS REACHING UP TO 35 KNOTS OVER CENTRAL AND NORTH-CENTRAL
WISCONSIN. THESE GUSTY WINDS WILL SPREAD INTO EASTERN WISCONSIN
LATER THIS AFTERNOON. SOME CONCERN FOR THE DOOR PENINSULA AS WIND
DIRECTION AND PRESSURE RISES ARE FAVORABLE FOR NEAR WIND ADVISORY
WIND GUSTS FOR A FEW HOURS. THINK WILL FALL JUST SHORT OF THOSE
TYPES OF GUSTS THOUGH. PLENTY OF STRATO-CU AND SNOW SHOWERS WITHIN THE
ARCTIC AIR OVER THE ARROWHEAD AND HEADING TOWARDS NORTHERN
WISCONSIN. WINDS/TEMPS/WIND CHILLS/AND SNOW POTENTIAL ARE THE MAIN
FORECAST CONCERNS.
TONIGHT...THE ARCTIC COLD FRONT WILL EXIT NORTHEAST WISCONSIN LATE
IN THE AFTERNOON OR EARLY THIS EVENING. SHOULD SEE PRETTY GOOD WIND
GUSTS UP TO 40 MPH OVER DOOR COUNTY AS STRONG PRESSURE RISES ARRIVE
BEHIND THE FRONT EARLY THIS EVENING. GUSTS BETWEEN 30 AND 35 MPH
ARE POSSIBLE ELSEWHERE. THE WINDS SHOULD THEN SUBSIDE PRETTY
QUICKLY BY MID-EVENING AS ARCTIC AIR PLUNGES ACROSS NORTH-CENTRAL
AND NORTHEAST WISCONSIN...THOUGH WINDS SHOULD NOT DECOUPLE.
SCATTERED SNOW SHOWERS WILL LIKELY FOLLOW THE ARRIVAL OF THE
ARCTIC AIR ACROSS THE NORTH THIS EVENING...THEN DIMINISH/RETREAT
TO THE SNOWBELT AREAS OVERNIGHT. THE COMBINATION OF TEMPS FALLING
TO AROUND 10 OR 12 BELOW OVER N-C WISCONSIN AND PERSISTENT
NORTHWEST WINDS WILL HAVE WIND CHILLS FALLING BETWEEN 20 TO 25
BELOW OVER N-C WISCONSIN AND GENERALLY 10 TO 15 BELOW ELSEWHERE.
IN COORDINATION WITH WFOS MARQUETTE AND DULUTH...WILL NOT ISSUE A
WIND CHILL ADVISORY AND WILL INSTEAD HIGHLIGHT THE THREAT IN A
SPS.
WEDNESDAY...ARCTIC HIGH PRESSURE WILL REMAIN IN CONTROL ACROSS THE
REGION AS A WEAK DISTURBANCE SLIDES SOUTHEAST ACROSS THE CENTRAL
GREAT PLAINS. WILL SEE MID AND HIGH CLOUDS SPREAD OVERHEAD FROM
THIS DISTURBANCE...BUT NO REAL THREAT OF PRECIP THIS FAR INTO THE
ARCTIC AIR. BITTERLY COLD WIND CHILLS WILL BE MODERATING BY 9 OR 10
IN THE MORNING TO BETWEEN 10 AND 20 BELOW OVER N-C WISCONSIN. HIGHS
WILL BE RANGING FROM 5 TO 10 ABOVE OVER N-C WI TO 10 TO 15 FARTHER
SOUTH AND EAST.
.LONG TERM...WEDNESDAY NIGHT THROUGH TUESDAY
ISSUED AT 238 PM CST TUE FEB 24 2015
PATTERN ALOFT IS BEGINNING TO CHANGE...BUT NOT BEFORE ONE MORE
BATCH OF ARCTIC AIR PUSHES INTO THE AREA. EVENTUALLY A WESTERN
TROUGH WILL EMERGE AS THE RIDGE PREVIOUSLY IN PLACE REFORMS MORE
OVER THE PACIFIC. THE EASTERN TROUGH WILL RETREAT NORTH...AND
SOMETHING RESEMBLING A SOUTHERN STREAM WILL START TO BRING
SOUTHWEST FLOW ALOFT INTO WISCONSIN. THIS WILL BRING A WARMER AND
MORE MOIST AIRMASS FROM THE SOUTHWEST. THE RESULT WILL BE A SLOW
MODERATION OF TEMPERATURES THROUGH THE REST OF THE WEEK...FOLLOWED
BY CHANCES FOR SNOW LATE THIS WEEKEND AND EARLY NEXT WEEK.
WEDNESDAY NIGHT THROUGH SATURDAY...
PRIMARY FORECAST CHALLENGE IN THIS STRETCH WILL BE EARLY ON AS A NEW
ARCTIC AIRMASS SURGES INTO THE AREA WITH WEDNESDAY AND THURSDAY
NIGHTS SEEING THE LOWEST TEMPERATURES. HOWEVER...THE DEEP EASTERN
TROUGH PATTERN WE HAVE SEEN LATELY WILL BE DEAMPLIFYING. THIS MAY
HELP BLUNT THE DROP IN TEMPERATURES. IT WILL STILL BE VERY COLD
AND A PORTION OF THE AREA...PRIMARILY IN NORTH CENTRAL
WISCONSIN...MAY REQUIRE WIND CHILL ADVISORIES. EACH NIGHT HAS
ISSUES THOUGH. A SHORTWAVE WILL BE PASSING RELATIVELY NEAR THE
AREA WEDNESDAY NIGHT...AND THOUGH IT HAS APPEARED FOR SOME TIME
THAT IT WILL PASS WELL TO OUR SOUTH...GUIDANCE HAS DRIFTED NORTH
TODAY. IT IS POSSIBLE THAT FURTHER DRIFT MAY RESULT IN MORE
CLOUDINESS WHICH WOULD HELP ARREST THE FALL OF TEMPERATURES. ON
THURSDAY NIGHT...COLD TEMPERATURES WILL BE DRIVEN LARGELY BY THE
POTENTIAL FOR STRONG RADIATIONAL COOLING. BUT JUST HOW LOW WE GO
WILL DEPEND ON CLOUD COVER AND WHETHER OR NOT WINDS WILL BE CALM
OVERNIGHT...BOTH DIFFICULT THINGS TO FORECAST AT THIS RANGE. AFTER
THESE NIGHTS...THE AFOREMENTIONED PATTERN CHANGE SHOULD ENCOURAGE
A MODERATION OF TEMPERATURES FOR THE REST OF THE WEEK...THOUGH WE
ARE ONLY LOOKING TO AN INCREASE TO A LITTLE BELOW NORMAL FROM WELL
BELOW NORMAL.
ADDITIONALLY...THERE IS A SLIGHTLY INCREASED AREA OF OPEN WATER ON
LAKES SUPERIOR AND MICHIGAN AFTER RECENT GUSTY WINDS. THOUGH THE
WATER IS SURELY COLD...THE AIR MASS WILL BE COLDER AND WITH SOME
ONSHORE WIND TRAJECTORIES WEDNESDAY NIGHT...LAKE EFFECT FLURRIES
ARE NOT IMPOSSIBLE FOR THE VILAS COUNTY SNOW BELT AND PORTIONS OF
THE LAKE MICHIGAN SHORELINE IN EAST CENTRAL WISCONSIN...PARTICULARLY
THE BIT OF MANITOWOC COUNTY THAT JUTS OUT INTO THE LAKE AT
DIFFERENT ANGLE THAN THE REST OF THE SHORELINE.
SATURDAY NIGHT THROUGH TUESDAY...
WITH MORE SOUTHWEST FLOW ALOFT...A MID-LEVEL SHORTWAVE AND A WEAK
SURFACE LOW REFLECTION WILL BRING A CHANCE FOR SNOW TO THE AREA IN
THE SECOND HALF OF THE WEEKEND. AFTER A LARGE JUMP NORTH IN THE
MODEL GUIDANCE YESTERDAY THE ENVELOPE HAS SETTLED BACK TO THE
SOUTH A LITTLE BIT TODAY. THOUGH AT FIRST GLANCE IT APPEARS LIKE
THE AREA MAY STILL SEE A FAIR SHOT FOR SOME SYNOPTIC LIFT...A
DEEPER INVESTIGATION REVEALED LESS POTENTIAL THAN IT FIRST SEEMED.
STILL...THE WARMER AND MOISTER ADVECTION FROM THE SOUTHWEST MAKES
THE IDEA OF AT LEAST A LITTLE SNOW REASONABLE...PARTICULARLY IN
CENTRAL AND EAST CENTRAL WISCONSIN. IN THIS SCENARIO...IT WOULD BE
APPROPRIATE TO EXPECT SNOW TOTALS OF AROUND TWO INCHES OR LESS. A
COLD FRONT ASSOCIATED WITH A LOW AND ITS ATTENDANT SHORTWAVE IN
THE NORTHERN STREAM WILL SHIFT WINDS TO NORTHWESTERLY AND CUT OFF
THE SNOW. FORTUNATELY THE MORE ZONAL FLOW LOOKS TO PREVENT A
STRONG SURGE OF COLD AIR TO CHOP DOWN TEMPERATURES BEHIND THE
FRONT AT THIS TIME.
HOWEVER...AFTER ALL THIS TALK...IT IS IMPORTANT TO REMEMBER THAT
IT IS ONLY TUESDAY. THOUGH A BROAD SCENARIO IS PRESENT IN ALL THE
GUIDANCE AND CONFIDENCE IN THAT IS MODERATE TO HIGH...CONFIDENCE
IN THE DETAILS THIS FAR OUT IS RELATIVELY LOW...AND COULD HAVE
SIGNIFICANT INFLUENCES ON THE SENSIBLE WEATHER WITH THIS FEATURE.
IT WOULD NOT BE WISE TO RULE OUT A SOUTHERN MISS NOR HIGHER
SNOWFALL POTENTIAL FROM A NORTHWARD DEVIATION JUST YET.
&&
.AVIATION...FOR 06Z TAF ISSUANCE
ISSUED AT 1151 PM CST TUE FEB 24 2015
THE NEXT WEATHER SYSTEM WILL TRACK SW OF THE FORECAST AREA DURING
THIS TAF PERIOD...WITH MAINLY MID/HIGH CLOUDS EXPECTED OVER THE
REGION. SCT LIGHT LAKE EFFECT SNOW SHOWERS OR FLURRIES MAY
CONTINUE ACROSS VILAS COUNTY...AND NNE WINDS MAY BRING A FEW
FLURRIES TO THE MTW AREA WED EVENING. MOST PLACES WILL HAVE
PREVAILING VFR CONDITIONS...AND WINDS WILL BE GENERALLY LIGHT.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......LUCHS
AVIATION.......RE/TSK
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
225 AM CST FRI FEB 27 2015
.UPDATE...
827 PM CST
LAKE EFFECT SNOW IS STARTING TO WIND DOWN AS DRIER AIR MASS
ADVECTS INTO THE AREA ALLOWING FOR A WEAKENING OF THE BROKEN LES
BAND THAT HAD PERSISTED ALL DAY. AS PROGRESSIVELY DRIER AIR
CONTINUED TO FILTER IN TONIGHT AND EVENTUALLY ONSHORE COMPONENT TO
FLOW WEAKENS WOULD ANTICIPATE LES TO END IN PORTER COUNTY LATER
THIS EVENING OR JUST PAST MIDNIGHT. GIVEN EXPECTATIONS AND RECENT
RADAR TRENDS MAY SHORTEN THE DURATION OF THE LAKE EFFECT SNOW
WARNING IN THE NEXT HOUR OR TWO IF NOT CANCEL IT OUTRIGHT.
ELSEWHERE CLOUDINESS OVER SOUTHERN PORTIONS OF THE CWA IS LIKELY
TO SLOWLY DISSIPATE AND MOVE OUT LEAVING SKIES FAIRLY CLEAR ACROSS
THE AREA. CENTER OF THE HIGH PRESSURE IS STILL HUNDREDS OF MILE TO
OUR NORTHWEST BUT WITH FRESH SNOW PACK WOULD EXPECT GRADIENT TO BE
WEAK ENOUGH FOR WINDS TO FURTHER DECOUPLE OVERNIGHT...ESPECIALLY
WITH HIGH GROWING CLOSER IN TIME. SUSPECT THAT THE WIND CHILL
ADVISORY WILL BE HARD PRESSED TO VERIFY MOST AREAS WITH THE
TYPICALLY COLDER VALLEYS LIKELY SEEING WINDS GO CALM...LIKELY KRPJ
AND KFRD ALREADY HAVE OR WINDS TO STAY UP ENOUGH TO KEEP TEMPS
FROM TANKING. THE TOOTHPASTE IS OUT OF THE PROVERBIAL TUBE SO NOT
PLANNING ANY CHANGES TO THE WIND CHILL ADVISORY SINCE A FEW
LOCATIONS COULD TAG ADVISORY FOR AN HOUR OR TWO AND IT WILL BE
VERY COLD.
IZZI
&&
.SHORT TERM...
THROUGH SATURDAY...
243 PM...LAKE EFFECT IS NOW ORGANIZING INTO A SINGLE BAND AS
WINDS TURN MORE NORTHWEST ACROSS NORTHEAST IL AND THIS BAND IS
SHIFTING TO THE SOUTHEAST AND WILL BE OUT OF COOK COUNTY IN THE
NEXT HOUR OR SO. WILL BE EXPIRING LAKE COUNTY IL FROM THE WARNING
AND FOR NOW WILL LET COOK COUNTY RIDE UNTIL 6 PM...BUT IF CURRENT
TRENDS CONTINUE...IT PROBABLY WILL BE CANCELED EARLY.
HI RES GUIDANCE IS IN REASONABLE AGREEMENT THAT THE LAKE EFFECT
BAND WILL SHIFT INTO PORTER COUNTY BY EARLY/MID EVENING...SO
EXPECTED AMOUNTS IN NORTHERN LAKE COUNTY INDIANA ARE A BIT
UNCERTAIN BUT WITH RATES OF 1-2 INCHES PER HOUR IN THE BAND...ITS
POSSIBLE SOME ISOLATED AMOUNTS OF 3 TO 6 INCHES WILL BE POSSIBLE.
MORE CONFIDENCE WITH AMOUNTS INTO NORTHERN PORTER COUNTY AS THE
BAND REMAINS THERE FROM MID EVENING THROUGH THE OVERNIGHT HOURS
WITH LOCALLY 4 TO 7 INCHES...PERHAPS MOSTLY NEAR THE LAKE. THE
BAND THEN BEGINS TO SHIFT OUT OF THE LAKE TOWARD MORNING. SO NOT
PLANNING ANY CHANGES TO THE WARNING END TIME FOR EITHER LAKE OR
PORTER COUNTIES...THOUGH CONFIDENCE REGARDING WHEN EXACTLY PRECIP
ENDS IS A BIT UNCERTAIN.
HIGH PRESSURE BUILDS ACROSS THE MIDWEST TONIGHT AND THEN MOVES
ACROSS THE AREA ON FRIDAY. WINDS WILL SLOWLY DIMINISH OVERNIGHT
BUT LIKELY REMAIN IN THE 5-10 MPH. THIS COMBINED WITH TEMPS
DROPPING WELL BELOW ZERO AWAY FROM CHICAGO WILL RESULT IN WINDS
CHILLS 20 BELOW TO 25 BELOW ZERO ACROSS THE NORTHERN CWA AND INTO
THE 15 BELOW RANGE SOUTH OF I-80. VALUES ARE BIT MARGINAL INTO
CHICAGO AND ALONG THE I-80 CORRIDOR BUT PLAN TO ISSUE A WIND
CHILL ADVISORY OVERNIGHT INTO FRIDAY MORNING GENERALLY ALONG AND
NORTH OF I-80 IN ILLINOIS.
DESPITE THE LIGHT WINDS AND SUNNY SKIES ON FRIDAY AS THE HIGH
SLOWLY MOVES ACROSS THE AREA...THE AIRMASS WILL REMAIN VERY COLD
WITH HIGHS ONLY REACHING THE MID TO PERHAPS UPPER TEENS. TEMPS
WILL LIKELY TANK FRIDAY NIGHT AS THE HIGH SHIFTS EAST AND LIGHT
WINDS TURN SOUTHERLY. SATURDAY WILL BE DRY AND A BIT WARMER WITH
HIGHS IN THE LOWER/MID 20S WITH INCREASING CLOUDS IN THE
AFTERNOON. CMS
&&
.LONG TERM...
SATURDAY NIGHT THROUGH THURSDAY...
THE TIME FRAME WILL START OUT ACTIVE AS A PERIOD OF ACCUMULATING
SNOW IS APPEARING LIKELY SATURDAY NIGHT INTO SUNDAY. STEADILY
INCREASING UPPER LEVEL FLOW OUT AHEAD OF DIGGING TROUGH TO THE
NORTH WILL ALLOW SHORT WAVE ENERGY TO TRAVERSE THE REGION DURING
THIS PERIOD...WHILE ONGOING WAA PERSISTS. THIS SHOULD ALLOW SNOW
TO SPREAD NORTHEAST ACROSS THE CWA DURING THE EVENING HOURS WITH
SNOW LIKELY ACROSS MUCH OF THE CWA AFTER THE MIDNIGHT TIME
FRAME...THEN LIKELY CONTINUING INTO SUNDAY AFTERNOON. MOST
GUIDANCE IN AGREEMENT WITH OVERALL LARGE SCALE SETUP DURING THIS
TIME AND EVEN WITH THIS SNOW SPREADING OVER THE CWA.
HOWEVER...THERE DOES APPEAR TO BE SOME TIMING DIFFERENCES OF THE
ONSET AND TIMING OF BEST SNOWFALL. SO I DO FEEL IT WILL SNOW AND
HAVE LIKELY POPS OVER THE ENTIRE CWA LATE SATURDAY NIGHT INTO
SUNDAY MORNING...BUT DID NOT GO TO CATEGORICAL BASED ON THE
PREVIOUSLY MENTIONED UNCERTAINTIES. ONLY MINOR CHANGES MADE TO THE
CURRENT SNOW FORECAST WITH THE BEST FORCING AND HIGHEST SNOWFALL
TOTALS CURRENTLY EXPECTED TO BE SOUTH OF I80. WHILE MOST OF THE
CWA WILL LIKELY OBSERVE ACCUMULATING SNOWFALL...THE SOUTHERN CWA
COULD APPROACH ADVISORY TYPE SNOW. HOWEVER I WONDER IF MY CURRENT
TOTAL MIGHT BE A LITTLE TOO HIGH...ESPECIALLY WITH THE ANTICIPATED
DRIVING MECHANISMS OF THIS SNOW...BUT THE LONGER DURATION OF THIS
LIGHT TO AT TIME MODERATE SNOW COULD HELP FOR THE CURRENT FORECAST
TOTALS. SYSTEM SNOW WILL DEPART TO THE EAST LATE SUNDAY AND SUNDAY
EVENING...AS HIGH PRESSURE BUILDS ACROSS THE REGION.
EARLY NEXT WEEK APPEARS TO BEGIN QUIET...BUT WITH ACTIVE WEATHER
RETURNING THROUGH MIDWEEK. HIGHLY AMPLIFIED PATTERN WITH UPPER
LEVEL RIDGE OVER THE EASTERN US AND A DIGGING TROUGH OVER THE
WESTERN CONUS WILL BE IN PLACE ON TUESDAY...AS DEEPENING SURFACE
LOW APPROACHES THE CWA FROM THE SOUTHWEST. STRONG WARM AIR AND
MOIST ADVECTION IS ANTICIPATED MONDAY NIGHT AND ESPECIALLY
TUESDAY/TUESDAY NIGHT. THIS WILL NOT ONLY PROVIDE THE POTENTIAL
FOR INITIAL VARYING PRECIP TYPE BUT WITH ALSO STEADIER
RAINFALL...AS A BROAD AREA OF PRECIP IS EXPECTED TO ACCOMPANY THIS
SYSTEM. EC AND GFS SIMILAR WITH REGARDS TO WAA...BUT WITH THE GFS
NOT AS ROBUST WITH THE MOISTURE ADVECTION AS THE EC IS APPEARING
TO BE. IF THE EC WERE TO VERIFY...THEN SURFACE DEWPOINTS COULD
APPROACH 50 DEG AND 850MB DEWPOINTS APPROACHING 10-11C. THIS WILL
BE CONCERNING FOR POSSIBLE HYDRO ISSUES...ESPECIALLY WITH THE
ANTICIPATED SNOW THIS WEEKEND. THERMAL PROFILES SUPPORTIVE OF ALL
RAIN ON TUESDAY AND ALTHOUGH I HAVENT INCLUDED THUNDER IN THE
GRIDS AT THIS TIME...WILL NEED TO MONITOR THIS POTENTIAL AS
WELL...ESPECIALLY FOR THE SOUTHERN CWA.
RODRIGUEZ
&&
.CLIMATE...
TEMPERATURES ARE FORECAST ONCE AGAIN TO BE CLOSE OR BREAK THE
FOLLOWING DAILY RECORDS THROUGH THE END OF THE MONTH...INCLUDING
ONE ON FRIDAY IN ROCKFORD THAT WAS SET JUST LAST WINTER:
ROCKFORD...
FRIDAY FEB 27TH LOW MAXIMUM: 15 IN 2014
SATURDAY FEB 28TH LOW: -7 IN 1962
SATURDAY FEB 28TH LOW MAXIMUM: 17 IN 1962
CHICAGO...
FRIDAY FEB 27TH LOW: -6 IN 1897
SATURDAY FEB 28TH LOW: 0 IN 1884
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* NONE.
RATZER
//DISCUSSION...UPDATED 06Z...
HIGH PRESSURE CENTERED OVER THE MID-MISSOURI VALLEY EARLY THIS
MORNING WILL SPREAD SLOWLY EAST-SOUTHEAST ACROSS THE REGION
THROUGH TONIGHT. LIGHT NORTHWEST WINDS WILL BECOME WEST DURING THE
DAY AND SOUTHWEST TONIGHT...WITH SPEEDS GENERALLY LESS THAN 10 KT.
DRY ARCTIC AIR MASS WILL MAKE FOR MAINLY CLEAR SKIES THROUGH THE
PERIOD.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* HIGH FOR ALL ELEMENTS.
RATZER
//OUTLOOK FOR ORD/MDW FOR 12Z SATURDAY-12Z THURSDAY...UPDATED 00Z...
SATURDAY...VFR THEN SNOW DEVELOPING SATURDAY NIGHT. IFR LIKELY.
SUNDAY...PERIODS OF ACCUMULATING SNOW ENDING BY LATE AFTERNOON.
IFR LIKELY.
MONDAY...VFR THEN CHANCE OF WINTRY MIX AND IFR MONDAY NIGHT.
TUESDAY...RAIN AND IFR LIKELY...POSSIBLY ENDING AS LIGHT SNOW
TUESDAY NIGHT. IFR
WEDNESDAY...MVFR POSSIBLE.
RC
&&
.MARINE...
219 AM CST
MAIN PERIOD OF CONCERN FOR GUSTY 20-30 KT WINDS LOOKS TO BE SUNDAY
NIGHT INTO EARLY MONDAY...AND POTENTIALLY AGAIN ON WEDNESDAY. MUCH
OF LAKE REMAINS ICE COVERED...WITH ONLY THE CENTRAL AND SOUTHERN
PORTIONS WELL AWAY FROM SHORE APPEARING OPEN IN RECENT SATELLITE
DATA.
HIGH PRESSURE CENTERED OVER THE MID-MISSOURI RIVER VALLEY WILL MOVE
EAST-SOUTHEAST ACROSS THE MIDWEST SOUTH OF THE LAKES THROUGH TONIGHT
AND TO THE MID-ATLANTIC REGION BY LATE SATURDAY. MEANWHILE...LOW
PRESSURE WILL MOVE ACROSS HUDSON BAY TODAY...WITH A DEEPER TROUGH
DEVELOPING NORTH OF THE LAKES SATURDAY. THIS WILL RESULT IN WINDS
BECOMING WESTERLY OVER LAKE MICHIGAN TODAY...INCREASING A BIT INTO
THE 20 KT RANGE TONIGHT AS THE GRADIENT TIGHTENS UP BETWEEN THE HIGH
PASSING SOUTH OF THE LAKES AND LOW PRESSURE FARTHER TO THE NORTH.
SATURDAY INTO SUNDAY...WINDS WILL SHIFT TO THE SOUTH-SOUTHWEST AS A
COLD FRONTAL TROUGH APPROACHES FROM THE NORTHWEST. THE FRONT WILL
PASS ACROSS THE LAKE SUNDAY WITH A SHIFT BACK TO THE WEST...BECOMING
NORTHWEST AND BECOMING GUSTY 25-30 KT SUNDAY NIGHT INTO MONDAY
MORNING AS HIGH PRESSURE MOVES IN FROM THE WEST AND BRIEFLY TIGHTENS
THE GRADIENT ONCE AGAIN. THE HIGH WILL MOVE ACROSS THE SOUTHERN
LAKES AND MIDWEST MONDAY WITH NORTHWEST WINDS QUICKLY DIMINISHING
AND EVENTUALLY BECOMING SOUTHEASTERLY MONDAY NIGHT AS THE HIGH
SLIDES OFF TO THE EAST.
MEDIUM-RANGE MODEL RUNS INDICATE LOW PRESSURE WILL MOVE NEAR
SOUTHERN LAKE MICHIGAN TUESDAY OR TUESDAY NIGHT. CURRENT INDICATIONS
ARE THAT SOUTHEAST WINDS WILL INCREASE TUESDAY INTO THE 20 KT RANGE
OR SO...BEFORE BRIEFLY DECREASING AND VEERING NORTH-NORTHWEST BY
EARLY WEDNESDAY AND INCREASING INTO THE 25-30 KT RANGE AS COLDER AIR
ONCE AGAIN SURGES IN.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WIND CHILL ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022
UNTIL 9 AM FRIDAY.
IN...LAKE EFFECT SNOW WARNING...INZ002 UNTIL 6 AM FRIDAY.
LM...NONE.
&&
$$
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Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1139 PM CST Thu Feb 26 2015
.UPDATE...
ISSUED AT 900 PM CST THU FEB 26 2015
Small area of clouds continues to slowly move south this evening.
Also, some isolated flurries are also still occurring under this
cloud cover. Expect this to continue, mainly in eastern areas of
the CWA. This will eventually clear up overnight. Current forecast
has a good handle on this and with temp trends the rest of the
night. No update planned at this time.
&&
.SHORT TERM...(Tonight)
ISSUED AT 249 PM CST THU FEB 26 2015
Will issue a wind chill advisory for areas along and north of a
Jacksonville to Springfield to Decatur to Paris line overnight into
mid Fri morning for wind chills of 15-24F below zero with the
coldest wind chills in Knox and Stark counties around dawn Friday.
Wind chills reach near or below 15F below near Galesburg around
midnight, and se toward I-72 later tonight. Lows overnight to
range from 5-10F below zero from the IL river valley nw to zero to
5F above in southeast IL from I-70 se. Broken to overcast low
clouds still cover much of IL with some clearing far west central
and northern IL near WI border. Still getting scattered light snow
showers and areas of flurries over central IL (visibilities as low as
2-5 miles) due to lingering moisture off lake MI along with a short
wave dropping se into the area. HRRR may be a bit too progressive in
clearing low clouds from north to south during early and mid
evening. Low clouds to likely decrease over IL river valley early
this evening, but thinking it may take until overnight for
decreasing of low clouds in southeast IL since short wave still
affecting southern counties tonight. Also lingered chance of
flurries from I-55 east late this afternoon and early evening and
into mid evening in southeast IL. Strong 1042 mb arctic high
pressure near the MT/ND and southern Saskatchewan border and ridging
SSE into the Great Plains to settle se into IA/MO by Friday morning
bringing dry weather and bitter cold temperatures overnight into Fri
morning. North winds 10-17 mph and gusts 18-24 mph this afternoon
will veer nw and decrease to 5-10 mph overnight.
&&
.LONG TERM...(Friday through Thursday)
ISSUED AT 249 PM CST THU FEB 26 2015
Morning upper air and satellite imagery depicts trough over the
central plains with clipper shortwave moving over IL, producing
continued light snow in strong 850mb cold air advection. Wave
continuing to move east and will break up in afternoon.
Ridge of high pressure to build in overnight, again producing wind
chills. Ridge to move off to the east through Friday and into
Saturday. By Saturday afternoon, overrunning from the next system
begins to develop into plains. NAM model brings snow into western IL
and feel not unreasonable. Will therefore add slight chc pops Sat
afternoon, with main pcpn Sat night to Sunday.
Models similar in development of frontal zone from western plains
low into Ozarks, with significant lift over boundary Saturday night.
This will push snow formation into central IL Saturday night,
continuing into Sunday. Main lift is Saturday night as upper wave
moves across great lakes, with pcpn lingering into Sunday. Diminshed
the pcpn Sun night as high pressure builds in.
Upper flow changes Monday to Tuesday, with pcpn again developing
into Monday night to Tuesday as surface low center develops in
plains and moves northeast, west of cwa though. The result is that
with this feature, area stays in the warm section and so pcpn starts
as freezing rain and changes to rain. Still uncertainty though, as
the operational models are very different on the timing of the
system movement. made few changes due to these differences.
&&
.AVIATION...(For the 06Z TAFS through 06Z Friday night)
ISSUED AT 1139 PM CST THU FEB 26 2015
VFR conditions will prevail at all TAF sites next 24hrs. Clouds
around 4.5kft are still effecting BMI/DEC/CMI late tonight but are
slowly moving southeast and should clear BMI and DEC by 06z, and
CMI by 09z. Will keep a 2hr TEMPO group for DEC and CMI just
because it seems these clouds are just lingering and will not go
quickly. Then clear skies should prevail remainder of the TAF
period. Winds will be northwest overnight and then become light
and variable tomorrow.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY until 10 AM CST Friday FOR ILZ027>031-
036>038-040>051-053-055-057.
&&
$$
UPDATE...Auten
SHORT TERM...07
LONG TERM...Goetsch
AVIATION...Auten
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1112 PM CST THU FEB 26 2015
.UPDATE...
827 PM CST
LAKE EFFECT SNOW IS STARTING TO WIND DOWN AS DRIER AIR MASS
ADVECTS INTO THE AREA ALLOWING FOR A WEAKENING OF THE BROKEN LES
BAND THAT HAD PERSISTED ALL DAY. AS PROGRESSIVELY DRIER AIR
CONTINUED TO FILTER IN TONIGHT AND EVENTUALLY ONSHORE COMPONENT TO
FLOW WEAKENS WOULD ANTICIPATE LES TO END IN PORTER COUNTY LATER
THIS EVENING OR JUST PAST MIDNIGHT. GIVEN EXPECTATIONS AND RECENT
RADAR TRENDS MAY SHORTEN THE DURATION OF THE LAKE EFFECT SNOW
WARNING IN THE NEXT HOUR OR TWO IF NOT CANCEL IT OUTRIGHT.
ELSEWHERE CLOUDINESS OVER SOUTHERN PORTIONS OF THE CWA IS LIKELY
TO SLOWLY DISSIPATE AND MOVE OUT LEAVING SKIES FAIRLY CLEAR ACROSS
THE AREA. CENTER OF THE HIGH PRESSURE IS STILL HUNDREDS OF MILE TO
OUR NORTHWEST BUT WITH FRESH SNOW PACK WOULD EXPECT GRADIENT TO BE
WEAK ENOUGH FOR WINDS TO FURTHER DECOUPLE OVERNIGHT...ESPECIALLY
WITH HIGH GROWING CLOSER IN TIME. SUSPECT THAT THE WIND CHILL
ADVISORY WILL BE HARD PRESSED TO VERIFY MOST AREAS WITH THE
TYPICALLY COLDER VALLEYS LIKELY SEEING WINDS GO CALM...LIKELY KRPJ
AND KFRD ALREADY HAVE OR WINDS TO STAY UP ENOUGH TO KEEP TEMPS
FROM TANKING. THE TOOTHPASTE IS OUT OF THE PROVERBIAL TUBE SO NOT
PLANNING ANY CHANGES TO THE WIND CHILL ADVISORY SINCE A FEW
LOCATIONS COULD TAG ADVISORY FOR AN HOUR OR TWO AND IT WILL BE
VERY COLD.
IZZI
&&
.SHORT TERM...
THROUGH SATURDAY...
243 PM...LAKE EFFECT IS NOW ORGANIZING INTO A SINGLE BAND AS
WINDS TURN MORE NORTHWEST ACROSS NORTHEAST IL AND THIS BAND IS
SHIFTING TO THE SOUTHEAST AND WILL BE OUT OF COOK COUNTY IN THE
NEXT HOUR OR SO. WILL BE EXPIRING LAKE COUNTY IL FROM THE WARNING
AND FOR NOW WILL LET COOK COUNTY RIDE UNTIL 6 PM...BUT IF CURRENT
TRENDS CONTINUE...IT PROBABLY WILL BE CANCELED EARLY.
HI RES GUIDANCE IS IN REASONABLE AGREEMENT THAT THE LAKE EFFECT
BAND WILL SHIFT INTO PORTER COUNTY BY EARLY/MID EVENING...SO
EXPECTED AMOUNTS IN NORTHERN LAKE COUNTY INDIANA ARE A BIT
UNCERTAIN BUT WITH RATES OF 1-2 INCHES PER HOUR IN THE BAND...ITS
POSSIBLE SOME ISOLATED AMOUNTS OF 3 TO 6 INCHES WILL BE POSSIBLE.
MORE CONFIDENCE WITH AMOUNTS INTO NORTHERN PORTER COUNTY AS THE
BAND REMAINS THERE FROM MID EVENING THROUGH THE OVERNIGHT HOURS
WITH LOCALLY 4 TO 7 INCHES...PERHAPS MOSTLY NEAR THE LAKE. THE
BAND THEN BEGINS TO SHIFT OUT OF THE LAKE TOWARD MORNING. SO NOT
PLANNING ANY CHANGES TO THE WARNING END TIME FOR EITHER LAKE OR
PORTER COUNTIES...THOUGH CONFIDENCE REGARDING WHEN EXACTLY PRECIP
ENDS IS A BIT UNCERTAIN.
HIGH PRESSURE BUILDS ACROSS THE MIDWEST TONIGHT AND THEN MOVES
ACROSS THE AREA ON FRIDAY. WINDS WILL SLOWLY DIMINISH OVERNIGHT
BUT LIKELY REMAIN IN THE 5-10 MPH. THIS COMBINED WITH TEMPS
DROPPING WELL BELOW ZERO AWAY FROM CHICAGO WILL RESULT IN WINDS
CHILLS 20 BELOW TO 25 BELOW ZERO ACROSS THE NORTHERN CWA AND INTO
THE 15 BELOW RANGE SOUTH OF I-80. VALUES ARE BIT MARGINAL INTO
CHICAGO AND ALONG THE I-80 CORRIDOR BUT PLAN TO ISSUE A WIND
CHILL ADVISORY OVERNIGHT INTO FRIDAY MORNING GENERALLY ALONG AND
NORTH OF I-80 IN ILLINOIS.
DESPITE THE LIGHT WINDS AND SUNNY SKIES ON FRIDAY AS THE HIGH
SLOWLY MOVES ACROSS THE AREA...THE AIRMASS WILL REMAIN VERY COLD
WITH HIGHS ONLY REACHING THE MID TO PERHAPS UPPER TEENS. TEMPS
WILL LIKELY TANK FRIDAY NIGHT AS THE HIGH SHIFTS EAST AND LIGHT
WINDS TURN SOUTHERLY. SATURDAY WILL BE DRY AND A BIT WARMER WITH
HIGHS IN THE LOWER/MID 20S WITH INCREASING CLOUDS IN THE
AFTERNOON. CMS
&&
.LONG TERM...
SATURDAY NIGHT THROUGH THURSDAY...
THE TIME FRAME WILL START OUT ACTIVE AS A PERIOD OF ACCUMULATING
SNOW IS APPEARING LIKELY SATURDAY NIGHT INTO SUNDAY. STEADILY
INCREASING UPPER LEVEL FLOW OUT AHEAD OF DIGGING TROUGH TO THE
NORTH WILL ALLOW SHORT WAVE ENERGY TO TRAVERSE THE REGION DURING
THIS PERIOD...WHILE ONGOING WAA PERSISTS. THIS SHOULD ALLOW SNOW
TO SPREAD NORTHEAST ACROSS THE CWA DURING THE EVENING HOURS WITH
SNOW LIKELY ACROSS MUCH OF THE CWA AFTER THE MIDNIGHT TIME
FRAME...THEN LIKELY CONTINUING INTO SUNDAY AFTERNOON. MOST
GUIDANCE IN AGREEMENT WITH OVERALL LARGE SCALE SETUP DURING THIS
TIME AND EVEN WITH THIS SNOW SPREADING OVER THE CWA.
HOWEVER...THERE DOES APPEAR TO BE SOME TIMING DIFFERENCES OF THE
ONSET AND TIMING OF BEST SNOWFALL. SO I DO FEEL IT WILL SNOW AND
HAVE LIKELY POPS OVER THE ENTIRE CWA LATE SATURDAY NIGHT INTO
SUNDAY MORNING...BUT DID NOT GO TO CATEGORICAL BASED ON THE
PREVIOUSLY MENTIONED UNCERTAINTIES. ONLY MINOR CHANGES MADE TO THE
CURRENT SNOW FORECAST WITH THE BEST FORCING AND HIGHEST SNOWFALL
TOTALS CURRENTLY EXPECTED TO BE SOUTH OF I80. WHILE MOST OF THE
CWA WILL LIKELY OBSERVE ACCUMULATING SNOWFALL...THE SOUTHERN CWA
COULD APPROACH ADVISORY TYPE SNOW. HOWEVER I WONDER IF MY CURRENT
TOTAL MIGHT BE A LITTLE TOO HIGH...ESPECIALLY WITH THE ANTICIPATED
DRIVING MECHANISMS OF THIS SNOW...BUT THE LONGER DURATION OF THIS
LIGHT TO AT TIME MODERATE SNOW COULD HELP FOR THE CURRENT FORECAST
TOTALS. SYSTEM SNOW WILL DEPART TO THE EAST LATE SUNDAY AND SUNDAY
EVENING...AS HIGH PRESSURE BUILDS ACROSS THE REGION.
EARLY NEXT WEEK APPEARS TO BEGIN QUIET...BUT WITH ACTIVE WEATHER
RETURNING THROUGH MIDWEEK. HIGHLY AMPLIFIED PATTERN WITH UPPER
LEVEL RIDGE OVER THE EASTERN US AND A DIGGING TROUGH OVER THE
WESTERN CONUS WILL BE IN PLACE ON TUESDAY...AS DEEPENING SURFACE
LOW APPROACHES THE CWA FROM THE SOUTHWEST. STRONG WARM AIR AND
MOIST ADVECTION IS ANTICIPATED MONDAY NIGHT AND ESPECIALLY
TUESDAY/TUESDAY NIGHT. THIS WILL NOT ONLY PROVIDE THE POTENTIAL
FOR INITIAL VARYING PRECIP TYPE BUT WITH ALSO STEADIER
RAINFALL...AS A BROAD AREA OF PRECIP IS EXPECTED TO ACCOMPANY THIS
SYSTEM. EC AND GFS SIMILAR WITH REGARDS TO WAA...BUT WITH THE GFS
NOT AS ROBUST WITH THE MOISTURE ADVECTION AS THE EC IS APPEARING
TO BE. IF THE EC WERE TO VERIFY...THEN SURFACE DEWPOINTS COULD
APPROACH 50 DEG AND 850MB DEWPOINTS APPROACHING 10-11C. THIS WILL
BE CONCERNING FOR POSSIBLE HYDRO ISSUES...ESPECIALLY WITH THE
ANTICIPATED SNOW THIS WEEKEND. THERMAL PROFILES SUPPORTIVE OF ALL
RAIN ON TUESDAY AND ALTHOUGH I HAVENT INCLUDED THUNDER IN THE
GRIDS AT THIS TIME...WILL NEED TO MONITOR THIS POTENTIAL AS
WELL...ESPECIALLY FOR THE SOUTHERN CWA.
RODRIGUEZ
&&
.CLIMATE...
TEMPERATURES ARE FORECAST ONCE AGAIN TO BE CLOSE OR BREAK THE
FOLLOWING DAILY RECORDS THROUGH THE END OF THE MONTH...INCLUDING
ONE ON FRIDAY IN ROCKFORD THAT WAS SET JUST LAST WINTER:
ROCKFORD...
FRIDAY FEB 27TH LOW MAXIMUM: 15 IN 2014
SATURDAY FEB 28TH LOW: -7 IN 1962
SATURDAY FEB 28TH LOW MAXIMUM: 17 IN 1962
CHICAGO...
FRIDAY FEB 27TH LOW: -6 IN 1897
SATURDAY FEB 28TH LOW: 0 IN 1884
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* NONE.
RATZER
//DISCUSSION...UPDATED 06Z...
HIGH PRESSURE CENTERED OVER THE MID-MISSOURI VALLEY EARLY THIS
MORNING WILL SPREAD SLOWLY EAST-SOUTHEAST ACROSS THE REGION
THROUGH TONIGHT. LIGHT NORTHWEST WINDS WILL BECOME WEST DURING THE
DAY AND SOUTHWEST TONIGHT...WITH SPEEDS GENERALLY LESS THAN 10 KT.
DRY ARCTIC AIR MASS WILL MAKE FOR MAINLY CLEAR SKIES THROUGH THE
PERIOD.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* HIGH FOR ALL ELEMENTS.
RATZER
//OUTLOOK FOR ORD/MDW FOR 12Z SATURDAY-12Z THURSDAY...UPDATED 00Z...
SATURDAY...VFR THEN SNOW DEVELOPING SATURDAY NIGHT. IFR LIKELY.
SUNDAY...PERIODS OF ACCUMULATING SNOW ENDING BY LATE AFTERNOON.
IFR LIKELY.
MONDAY...VFR THEN CHANCE OF WINTRY MIX AND IFR MONDAY NIGHT.
TUESDAY...RAIN AND IFR LIKELY...POSSIBLY ENDING AS LIGHT SNOW
TUESDAY NIGHT. IFR
WEDNESDAY...MVFR POSSIBLE.
RC
&&
.MARINE...
215 PM CST
THE FAR NORTHERN PORTIONS OF THE LAKE REMAINS ICE COVERED AS DO
THE SOUTHERN NEARSHORE WATERS. THERE...WAVES HAVE REMOVED FROM THE
FORECAST FOR THESE AREAS.
HIGH PRESSURE EXTENDS FROM THE NORTHERN PLAINS...WITH A CENTRAL
PRESSURE OF 30.8 INCHES...SOUTH THROUGH TEXAS AND EAST ACROSS THE
GREAT LAKES. THE CENTER OF THE HIGH WILL CONTINUE TO DROP TO THE
SOUTHEAST...TO THE UPPER MISSOURI VALLEY BY FRIDAY MORNING. WITH
RIDGE AXIS EXTENDING ACROSS LAKE MICHIGAN...A CONVERGENCE BAND HAS
SET UP WITH A PLUME OF LAKE EFFECT SNOW MOVING ACROSS THE SOUTHERN
PORTIONS OF THE LAKE. AS THE CENTER OF THE HIGH CONTINUES TO
SETTLE INTO THE OHIO VALLEY FRIDAY AND FRIDAY NIGHT...WINDS OVER
THE LAKE WILL BACK FROM NORTHERLY TO WESTERLY FRIDAY NIGHT AND
SATURDAY. AS THE HIGH MOVES OFF TO THE EAST...A WEAK COLD FRONT IS
EXPECTED TO CROSS THE UPPER MISSISSIPPI VALLEY SATURDAY
NIGHT...BACKING WINDS OVER THE LAKE TO SOUTHWESTERLY. THROUGH THIS
PERIOD...WINDS WILL BE ON A GENERAL WEAKENING TREND. THE WEAK COLD
FRONT IS EXPECTED TO SWEEP ACROSS THE LAKE SUNDAY EVENING WITH
ANOTHER ARCTIC HIGH QUICKLY FOLLOWING IN IT`S WAKE. THIS HIGH WILL
TAKE A MORE NORTHERLY TRACK...WITH THE CENTER OF THE HIGH CROSSING
THE LAKE SUNDAY NIGHT AND MONDAY...LEADING TO A SHORT PERIOD OF
LIGHT AND VARIABLE WINDS. THE HIGH SHOULD THEN PUSH EAST OF THE
LAKE MONDAY AND MONDAY NIGHT AS LOW PRESSURE DEVELOPS OVER
KANSAS/NEBRASKA IN THE LEE OF THE ROCKIES...SETTING UP A PERIOD OF
SOUTHEAST WINDS AS AN ASSOCIATED WARM FRONT EXTENDS EAST OF THE
LOW...TO THE OHIO VALLEY. THE LOW IS EXPECTED TO DEEPEN TO 29.1
INCHES AS IT TRACKS NORTHEAST AND CROSSES THE MIDDLE OF LAKE
MICHIGAN TUESDAY EVENING.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WIND CHILL ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022
UNTIL 9 AM FRIDAY.
IN...LAKE EFFECT SNOW WARNING...INZ002 UNTIL 6 AM FRIDAY.
LM...NONE.
&&
$$
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
900 PM CST Thu Feb 26 2015
.UPDATE...
ISSUED AT 900 PM CST THU FEB 26 2015
Small area of clouds continues to slowly move south this evening.
Also, some isolated flurries are also still occurring under this
cloud cover. Expect this to continue, mainly in eastern areas of
the CWA. This will eventually clear up overnight. Current forecast
has a good handle on this and with temp trends the rest of the
night. No update planned at this time.
&&
.SHORT TERM...(Tonight)
ISSUED AT 249 PM CST THU FEB 26 2015
Will issue a wind chill advisory for areas along and north of a
Jacksonville to Springfield to Decatur to Paris line overnight into
mid Fri morning for wind chills of 15-24F below zero with the
coldest wind chills in Knox and Stark counties around dawn Friday.
Wind chills reach near or below 15F below near Galesburg around
midnight, and se toward I-72 later tonight. Lows overnight to
range from 5-10F below zero from the IL river valley nw to zero to
5F above in southeast IL from I-70 se. Broken to overcast low
clouds still cover much of IL with some clearing far west central
and northern IL near WI border. Still getting scattered light snow
showers and areas of flurries over central IL (visibilities as low as
2-5 miles) due to lingering moisture off lake MI along with a short
wave dropping se into the area. HRRR may be a bit too progressive in
clearing low clouds from north to south during early and mid
evening. Low clouds to likely decrease over IL river valley early
this evening, but thinking it may take until overnight for
decreasing of low clouds in southeast IL since short wave still
affecting southern counties tonight. Also lingered chance of
flurries from I-55 east late this afternoon and early evening and
into mid evening in southeast IL. Strong 1042 mb arctic high
pressure near the MT/ND and southern Saskatchewan border and ridging
SSE into the Great Plains to settle se into IA/MO by Friday morning
bringing dry weather and bitter cold temperatures overnight into Fri
morning. North winds 10-17 mph and gusts 18-24 mph this afternoon
will veer nw and decrease to 5-10 mph overnight.
&&
.LONG TERM...(Friday through Thursday)
ISSUED AT 249 PM CST THU FEB 26 2015
Morning upper air and satellite imagery depicts trough over the
central plains with clipper shortwave moving over IL, producing
continued light snow in strong 850mb cold air advection. Wave
continuing to move east and will break up in afternoon.
Ridge of high pressure to build in overnight, again producing wind
chills. Ridge to move off to the east through Friday and into
Saturday. By Saturday afternoon, overrunning from the next system
begins to develop into plains. NAM model brings snow into western IL
and feel not unreasonable. Will therefore add slight chc pops Sat
afternoon, with main pcpn Sat night to Sunday.
Models similar in development of frontal zone from western plains
low into Ozarks, with significant lift over boundary Saturday night.
This will push snow formation into central IL Saturday night,
continuing into Sunday. Main lift is Saturday night as upper wave
moves across great lakes, with pcpn lingering into Sunday. Diminshed
the pcpn Sun night as high pressure builds in.
Upper flow changes Monday to Tuesday, with pcpn again developing
into Monday night to Tuesday as surface low center develops in
plains and moves northeast, west of cwa though. The result is that
with this feature, area stays in the warm section and so pcpn starts
as freezing rain and changes to rain. Still uncertainty though, as
the operational models are very different on the timing of the
system movement. made few changes due to these differences.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
ISSUED AT 548 PM CST THU FEB 26 2015
clouds and light snow showers continue at SPI/DEC/CMI. When the
snow occurs, cigs are MVFR and vis is below 5SM. PIA and BMI just
have clouds, but VFR levels. All sites will remain mostly cloudy
most of the evening and since clouds are not diurnal, they will
continue for several hours after sunset. So, think clearing will
occur close to midnight. With all the low level moisture around
tomorrow, believe scattered lower SC or CU will develop in the
morning. Winds will be north-northwest early and then become
northwest close to midnight. With ridging over the area tomorrow,
winds will be light.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY from Midnight tonight to 10 AM CST Friday
FOR ILZ027>031-036>038-040>051-053-055-057.
&&
$$
UPDATE...Auten
SHORT TERM...07
LONG TERM...Goetsch
AVIATION...Auten
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
307 AM CST FRI FEB 27 2015
.SYNOPSIS...
ISSUED AT 307 AM CST FRI FEB 27 2015
HIGH PRESSURE WAS MOVING INTO THE CENTRAL PLAINS EARLY THIS
MORNING. WITH FRESH SNOWFALL AND CLEAR SKIES TEMPERATURES HAVE
PLUMMETED THIS MORNING TO QUITE POSSIBLY ONE OF THE COLDEST NIGHTS
OF THE YEAR. WINDS HAVE STAYED UP...WHICH HAS LEAD TO WIDESPREAD
WIND CHILLS BETWEEN 20 AND 30 BELOW ZERO WITH A FEW POCKETS OF 30
BELOW OR LOWER WIND CHILLS. WINDS ARE STARTING TO WANE AND
TEMPERATURES SHOULD DROP MORE.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 307 AM CST FRI FEB 27 2015
MAIN FORECAST CONCERN FOR THE SHORT TERM ARE TEMPERATURES TODAY
AND TONIGHT ACROSS THE AREA. WITH HIGH PRESSURE IN PLACE AND FRESH
SNOW COVER...GUIDANCE IS OF LITTLE HELP FOR TEMPERATURE FORECASTS.
AS FAR AS THE SYNOPTIC PATTERN IS CONCERNED...H5 RIDGING IS
BUILDING INTO THE CENTRAL UNITED STATES AS A SURFACE HIGH IS PROG
TO MOVE DIRECTLY OVER OUR CWA TODAY. WINDS SHOULD WANE...HOWEVER
COLD AIR AND FRESH SNOWFALL WILL LEAD TO COLD TEMPERATURES TODAY
AND TONIGHT. MODELS ARE OF LITTLE HELP...THIS MORNING FOR LOWS I
LOADED THE OBS AND THEN MADE TWEAKS FROM THERE AS THE RUC WAS THE
ONLY MODEL COLD ENOUGH WITH TEMPS. FOR TODAY AND TONIGHT...WENT
WITH THE ALLBLEND AND THEN TWEAKED TEMPERATURES FROM THERE. WIND
CHILLS TONIGHT SUGGEST THE NEED FOR ANOTHER WIND CHILL ADVISORY
FOR AREAS NORTH OF I80. WILL DEFER TO THE DAY TO SHIFT TO DECIDE
TO ISSUE THIS AS THERE IS ALREADY ONE OUT.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 307 AM CST FRI FEB 27 2015
TWO STORM SYSTEMS WILL IMPACT THE EXTENDED FORECAST...AND BOTH
CONTAIN POTENTIAL WINTER IMPACTS. AT THIS TIME...BOTH SYSTEMS ARE
RELATIVELY POOR IN CONFIDENCE OF EXACT DETAILS CONCERNING THESE
IMPACTS.
TO BEGIN THE EXTENDED...HIGH PRESSURE WILL BE MOVING OFF TO THE EAST
SATURDAY...AND WITH A VERY COLD START TO THE DAY...THE WEAK WAA WILL
LIKELY ONLY RESULT IN HIGHS IN THE MID TEENS NORTH TO MID 20S
SOUTH...DESPITE A HEALTHY AMOUNT OF LATE FEBRUARY SUNSHINE IN THE
MORNING. WARM ADVECTION BY AFTERNOON...WILL BRING MID LEVEL MOISTURE
NORTHWARD...WITH SOME MODELS CONTINUING TO BRUSH OUR SOUTHWEST WITH
DEEPER SATURATION BY LATE AFTERNOON. THE MODEL BLEND SHOWS FAR MORE
SIGNIFICANT MOISTURE ADVECTION BY SATURDAY NIGHT...AND I WILL
CONTINUE TO HIGHLIGHT THAT PERIOD THROUGH SUNDAY WITH HIGH POPS.
THIS EVENT IS GOING TO BE ALL SNOW...AND SHOULD HAVE RATIOS IN THE
12 TO 15 TO 1 RANGE...THUS AMOUNTS FROM SATURDAY EVENING THROUGH
SUNDAY AFTERNOON SHOULD RANGE FROM AROUND 1 INCH NORTHWEST...TO 2 TO
3 INCHES FROM IOWA CITY THROUGH THE QUAD CITIES TO STERLING...TO 3
TO 5 INCHES OVER FAR SOUTHEAST IOWA NORTHEAST MISSOURI TO NEAR
PRINCETON ILLINOIS. WHILE THOSE AMOUNTS ARE SUPPORTED BY THE MOST
LIKELY BLEND OF GUIDANCE THAT IS INDICATED AT THIS TIME...I AM NOT
CONFIDENT IN THEM YET. THE EVENT IS LIKELY GOING TO FALL INTO THE
ADVISORY RANGE...ESPECIALLY DUE TO THE LONGER THAN NORMAL DURATION
FOR THESE RANGE OF AMOUNTS. LOOKING AT UNCERTAINTY...THE CANADIAN
MODEL IS FARTHER SOUTH THAN THE ECMWF AND GFS...AND KEEPS THE
NORTHERN 3/4S OF THE CWA DRY...THUS ANOTHER REASON FOR HOLDING OFF
ON ANY EARLY HEADLINE AT THIS TIME. THE 06Z NAM...THROUGH 12Z
SUNDAY...ALSO KEEPS THE BULK OF MOISTURE AND FORCING SOUTH.
MONDAY WILL BE A BREAK BETWEEN LOW CONFIDENCE SYSTEM...AS THE DEEP
WESTERN TROF BECOMES EVEN MORE AMPLIFIED. THE MODELS HAVE SHOWN VERY
LITTLE CONSISTENCY OVER THE PAST FEW DAYS AND THROUGH TONIGHT WITH
RESPECT TO THE LOW TRACK...UPPER ENERGY TRACK...AND BAROCLINICITY OF
THIS POTENTIAL SYSTEM. ONE FEATURE THAT HAS BEEN SHOWN
CONSISTENTLY...HAS BEEN MOISTURE...WITH A SYNOPTIC SIGNAL OF AN OPEN
GULF OF MEXICO...AND EVEN OPEN CARIBBEAN. THE HIGH AMOUNTS OF
AVAILABLE MOISTURE ARE REASONS SUPPORTING LIKELY POPS MONDAY NIGHT
AND TUESDAY. WHILE NOT CONFIDENT IN THERMAL TRANSITION TIMING...IT
IS A BEST MODEL BLEND...AND CONCEPTUAL MODEL FIT FOR PCPN TO BEGIN
AS A WINTRY MIX OF SNOW/SLEET/FREEZING RAIN MONDAY
NIGHT...TRANSITIONING TO RAIN TUESDAY...THEN BACK TO SNOW AGAIN
TUESDAY NIGHT. THIS WET MESS COULD BE HIGH IMPACT...OR COULD BE
LARGELY BENIGN. IT IS VERY DIFFICULT TO TELL...AND WILL KEEP A
HEALTHY DOSE OF UNCERTAINTY IN OUR PRODUCTS.
FOLLOWING THIS SYSTEM...COLDER DRY WEATHER SETTLES BACK IN THE A FEW
DAYS BEFORE MODERATION LOOKS TO OCCUR IN ZONAL FLOW.
ERVIN
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1134 PM CST THU FEB 26 2015
CLEAR SKIES AND LIGHT NORTHWEST TO WEST WINDS WILL CONTINUE
OVERNIGHT THROUGH FRIDAY KEEPING VFR CONDITIONS IN PLACE. ARCTIC
HIGH PRESSURE MOVING THROUGH THE REGION WILL RESULT IN BITTER COLD
TEMPERATURES.
&&
.CLIMATE...
ISSUED AT 307 AM CST FRI FEB 27 2015
COULD SEE RECORD LOWS THIS MORNING AT A FEW SITES AND POSSIBLY
AGAIN TONIGHT AT OTHER SITES. HERE ARE THE RECORDS FOR TONIGHT.
RECORD LOWS FOR FEBRUARY 28...
MOLINE.........-9 IN 1962
CEDAR RAPIDS...-17 IN 1962
DUBUQUE........-10 IN 1962
BURLINGTON.....-7 IN 1962
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...WIND CHILL ADVISORY UNTIL 9 AM CST THIS MORNING FOR BENTON-
BUCHANAN-CEDAR-CLINTON-DELAWARE-DES MOINES-DUBUQUE-HENRY IA-
IOWA-JACKSON-JEFFERSON-JOHNSON-JONES-KEOKUK-LEE-LINN-LOUISA-
MUSCATINE-SCOTT-VAN BUREN-WASHINGTON.
IL...WIND CHILL ADVISORY UNTIL 9 AM CST THIS MORNING FOR BUREAU-
CARROLL-HANCOCK-HENDERSON-HENRY IL-JO DAVIESS-MCDONOUGH-
MERCER-PUTNAM-ROCK ISLAND-STEPHENSON-WARREN-WHITESIDE.
MO...WIND CHILL ADVISORY UNTIL 9 AM CST THIS MORNING FOR CLARK-
SCOTLAND.
&&
$$
SYNOPSIS...GIBBS
SHORT TERM...GIBBS
LONG TERM...ERVIN
AVIATION...SHEETS
CLIMATE...GIBBS
AREA FORECAST DISCUSSION
NWS JACKSON KY
341 AM EST FRI FEB 27 2015
.UPDATE...
ISSUED AT 103 AM EST FRI FEB 27 2015
CURRENT CONDITIONS ACROSS EASTERN KENTUCKY FEATURE A WEAK ARCTIC
FRONT MOVING THROUGH THE AREA. ASSOCIATED WITH THE FRONT IS SOME
WEAK RETURNS SHOWING SOME FLURRIES AND SNOW SHOWERS. SOME OF THESE
SNOW SHOWERS HAVE PRODUCED A DUSTING AT MOST IN SOME AREAS WITH
SOME VISIBILITIES NEAR A MILE. THIS BAND HAS A FINE EDGE NOW
CROSSING I-64. THIS SHOULD BRING AN END TO THE ACTIVITY INTO THE
MORNING HOURS. HAVE SENT OUT SOME FRESHENED UP GRIDS TO ADDRESS
THIS AND TEMPERATURES AS THE COLDER AIR IS NOW PUSHING THROUGH THE
MIDWEST STATES AND NOW INTO KY. THOUGH NO SIGNIFICANT CHANGE WAS
MADE TO THE ZFP...THE GRIDS HAVE BEEN SENT TO THE NDFD SERVERS.
UPDATE ISSUED AT 945 PM EST THU FEB 26 2015
A DISTURBANCE IS WORKING THROUGH THE GREAT LAKES AND OH VALLEY
REGION AND IS BRINGING SOME VERY LIGHT SNOW OR FLURRIES TO THE
REGION. AWOS AND ASOS SITES OVER CENTRAL AND NORTHERN KY HAVE
REPORTED SNOW REACHING THE GROUND...BUT THE AIR MASS IS RATHER
DRY...SO VISIBILITIES AND CEILINGS HAVE NOT DROPPED ALL THAT FAR.
AT THIS POINT...PER RADAR AND SFC OBS IT APPEARS THAT THE LIGHT
SNOW OR FLURRIES IS NEARING THE SOMERSET TO JACKSON TO SANDY HOOK
LINE. ONLY ONE KY MESONET SITE IN CENTRAL KY HAS RECEIVED
MEASURABLE PRECIPITATION WITH THIS.
THE NEAR TERM MODELS SUCH AS THE HRRR CONTINUE TO HAVE THIS
DIMINISHING AS IT MOVES EAST...BUT IT SEEMS TO CLEARLY BE HOLDING
TOGETHER BETTER THAN THE HRRR IS FORECASTING. THE WINDS ARE BIT
MORE NORTHERLY THAN IDEAL FOR UPSLOPE ALTHOUGH THERE IS A BIT OF
AN UPSLOPE COMPONENT. THE CURRENT FORECAST IS MORE REFLECTIVE OF
THE MOST RECENT NAM AND GFS RUNS AS SEEMS MORE REASONABLE GIVEN
UPSTREAM TRENDS. AT THIS POINT...SLIGHT CHANCE TO CHANCE POPS
APPEAR TO REMAIN IN ORDER AND AN SPS IS ALREADY IN PLACE. SOME
LOCATIONS MAY PICK UP A QUARTER TO A HALF OF AN INCH OF FLUFF
WHILE OTHER LOCATIONS MAY ONLY GET A LIGHT DUSTING OR NOTHING AT
ALL. THE BIGGER STORY WILL BE THE COLDER AIR WORKING INTO THE
REGION LATE TONIGHT. LOWS SHOULD REACH THE UPPER SINGLE DIGITS
ABOVE ZERO NORTH...WITH UPPER TEENS NEAR THE TN BORDER. TEMPS WILL
STRUGGLE TO REACH THE MID TO UPPER 20S IN MANY LOCATIONS ON
FRIDAY...ALTHOUGH FRI NIGHT APPEARS TO BE COLDER ON AVERAGE THAN
TONIGHT.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 355 PM EST THU FEB 26 2015
19Z SFC ANALYSIS SHOWS LOW PRESSURE PASSING BY TO THE EAST WHILE A
DEEP LOW IS APPROACHING FROM THE NORTHWEST. AN ARCTIC COLD FRONT
FROM THIS IS MOVING INTO KENTUCKY AND THIS WILL SWEEP ACROSS
EASTERN KENTUCKY LATER THIS EVENING. ON REGIONAL RADAR...THE LIGHT
SNOW ASSOCIATED WITH THIS BOUNDARY IS STARTING TO SETTLE DEEPER
INTO THE STATE. EAST KENTUCKY SAW PARTLY SUNNY SKIES THIS
AFTERNOON WITH SOME LOW CLOUDS CLINGING TO OUR FAR EASTERN AREAS
WHILE HIGH CLOUDS PASSED THROUGH NORTHERN PARTS OF THE CWA. LOWER
CLOUDS ARE INBOUND FROM WESTERN AND CENTRAL KENTUCKY NOW...AHEAD
OF THAT FRONT. TEMPERATURES WERE ABLE TO SPIKE UP TO NEAR 40
DEGREES FOR MUCH OF THE AREA THIS AFTERNOON THANKS TO THE PARTIAL
SUNSHINE WHILE ONLY LOW 30S WERE ACHIEVED IN THE NORTHWEST.
DEWPOINTS REMAIN IN THE TEENS IN THE NORTHWEST WHILE LOWER AND
MIDDLE 20S ARE FOUND IN THE EAST. WINDS WERE GENERALLY FROM THE
NORTHWEST AT 5 TO 10 MPH WITH GUSTS TO 15 MPH.
THE MODELS ARE IN GOOD AGREEMENT ALOFT AS A WEAK WAVE PASSES TO
THE SOUTH OF THE AREA THIS EVENING FOLLOWED BY A STRONGER AND
LARGER TROUGH THAT SETTLES INTO THE OHIO VALLEY TONIGHT. THIS
TROUGH WILL BRING ITS CORE ENERGY ACROSS OHIO DURING THE DAY
FRIDAY BEFORE TAPERING OFF AMIDST REBOUNDING HEIGHTS OVER KENTUCKY
FRIDAY NIGHT. THE ECMWF IS A BIT QUICKER THAN THE OTHER MODELS
WITH THESE HEIGHT RISES AND MAY BE GETTING AHEAD OF ITSELF. GIVEN
THE GENERAL AGREEMENT...AT LEAST INTO FRIDAY EVENING...HAVE
FAVORED THE HIGHER RESOLUTION MODEL GUIDANCE FROM THE HRRR...
RAP13...AND NAM12 FOR WX SPECIFICS.
SENSIBLE WEATHER WILL FEATURE CLOUDS ARRIVING ALONG WITH SNOW
SHOWERS THIS EVENING AND CONTINUING THROUGH THE NIGHT IN
ASSOCIATION WITH THE ARCTIC AIR POURING BACK INTO THIS PART OF THE
STATE. TEMPERATURES WILL FALL INTO THE TEENS IN MOST PLACES BY
DAWN THANKS TO THE CAA WITH SOME SINGLE DIGITS POSSIBLE NORTH OF
INTERSTATE 64. ANY LINGERING SNOW SHOWERS WILL COME TO AN END
FRIDAY MORNING IN FAR EASTERN PARTS OF THE AREA WITH SOME SUNSHINE
POSSIBLE BY AFTERNOON...BUT TEMPERATURES WILL STILL STRUGGLE TO
MAKE IT INTO THE LOWER 20S BY MIDDAY. THIS SETS THE STAGE FOR A
VERY CHILLY NIGHT WITH SINGLE DIGITS LIKELY ON TAP FOR THE VALLEYS
AND MORE OPEN AREAS...WHILE SOME LATE ARRIVING HIGH CLOUDS AND THE
INVERSION MAY SPARE THE RIDGES THE COLDEST OF THE AIR. CANNOT RULE
OUT SOME FLURRIES ARRIVING TOWARD DAWN SATURDAY AHEAD OF THE NEXT
SYSTEM...BUT HAVE LEFT THEM OUT FOR NOW.
AGAIN USED THE CONSSHORT TO JUMP START THE T/TD/WIND GRIDS
THROUGH THE DAY FRIDAY...WITH SOME TERRAIN BASED ADJUSTMENTS MADE
AT NIGHT. AFTER THAT...USED THE SUPERBLEND TO INITIATE THE GRIDS
INTO SATURDAY MORNING WITH MINOR CHANGES. AS FOR POPS...ENDED UP
ON THE HIGH SIDE...CLOSER TO THE MET...OF RATHER LOW MOS GUIDANCE
TONIGHT...THEN SIMILAR FOR THE REST OF THE SHORT TERM.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 340 AM EST FRI FEB 27 2015
A VERY PERIOD IN STORE IN THE EXTENDED. THE PERIOD WILL ACTUALLY
START OFF FAIRLY QUIET...AS A WARM FRONTAL BOUNDARY MEANDERS ABOUT
ALONG THE OHIO RIVER. SNOW SHOWERS WILL BEGIN TO MOVE INTO THE
AREA AS THE WARM FRONT SAGS SOUTH AND INTERACTS WITH BELOW
FREEZING AIR THAT WILL ALREADY BE IN PLACE. THE SNOW SHOWERS WILL
CHANGE TO RAIN SHOWERS AND QUICKLY OVERSPREAD THE AREA SUNDAY AND
SUNDAY NIGHT AS THE COLD FRONT MAKES ITS WAY ACROSS THE AREA AND
WARM AIR SURGES NORTH AHEAD OF THE BOUNDARY. THE RAIN COULD BE
HEAVY TIMES SUNDAY NIGHT AND MONDAY. ONCE THE INITIAL COLD FRONT
EXITS THE AREA LATE IN THE DAY ON MONDAY...A LULL IN THE
PRECIPITATION IS EXPECTED...AS A RIDGE OF HIGH PRESSURE IS PROGGED
TO SETTLE OVER THE AREA FOR ABOUT 10 HOURS. AFTER THIS SHORT
RESPITE...ANOTHER ROUND OF RAIN AND SNOW SHOWERS IS EXPECTED AS A
WARM FRONT MOVES ACROSS THE AREA FROM THE SOUTH. THE PRECIPITATION
SHOULD CHANGE OVER TO ALL RAIN BY MID MORNING ON TUESDAY...AS WARM
GULF AIR PUSHES BACK INTO THE AREA AND OVERRIDES THE WARM FRONT.
THE RAIN IS EXPECTED TO BECOME WIDESPREAD DURING THE AFTERNOON AND
HOURS ON TUESDAY AND THROUGHOUT THE OVERNIGHT...AS ANOTHER COLD
FRONT PUSHES SLOWLY ACROSS THE AREA. THIS ROUND OF MODERATE TO
HEAVY RAIN IS FORECAST TO PERSIST THROUGH EARLY WEDNESDAY EVENING
BEFORE FINALLY LETTING UP. THE RAIN COULD BE HEAVY AT
TIMES...CREATING THE POTENTIAL FOR LOCALIZED FLOODING. HYDRO
ISSUES WILL ALSO BE POSSIBLE SUNDAY AFTERNOON THROUGH SUNDAY
NIGHT...AS WIDESPREAD RAIN WILL MELT THE EXISTING SNOW
PACK...WHICH WILL CREATE A LARGE AMOUNT OF RUNOFF THAT WILL MAKE
ITS WAY INTO AREA CREEKS AND STREAMS. THIS ADDITIONAL WATER WILL
LIKELY LEAD TO SIGNIFICANT RISES ON AREA RIVERS AS WELL.
A ROUND OF SCATTERED SNOW SHOWERS IS THEN EXPECTED TO MOVE IN
BEHIND THE DEPARTING COLD FRONT LATE WEDNESDAY NIGHT AND THURSDAY
MORNING...AS COLDER AIR FILTERS IN FROM THE WEST AND NORTHWEST.
ONLY LIGHT ACCUMULATIONS ARE POSSIBLE. THE PRECIPITATION SHOULD
FINALLY COME TO AN END LATE THURSDAY NIGHT. THE GOOD NEWS IS THAT
THE LOW TEMPERATURES WE ARE EXPECTING NEXT WEEK WILL NOT BE
ANYWHERE NEAR AS COLD AS WHAT WE HAVE EXPERIENCED THAT PAST TWO
WEEKS. THE FIRST COUPLE OF DAYS OF THE EXTENDED ARE FORECAST TO
FEATURE ONLY SLIGHTLY BELOW NORMAL TEMPERATURES...WITH LOWS ON
SUNDAY MORNING BOTTOMING OUT IN THE MID TO UPPER 20S ACROSS THE
AREA. HIGHS ON SUNDAY SHOULD BE ABLE TO CLIMB WELL INTO THE 40S
ACROSS THE AREA AS SOUTHERLY FLOW BEGINS TO DOMINATE THE AREA. THE
WARM UP IS EXPECTED TO CONTINUE ON TUESDAY AND WEDNESDAY...WITH
THE MERCURY FORECAST TO TOP OUT IN THE MID TO UPPER 50S AROUND
EASTERN KENTUCKY. A FEW LOCATIONS IN OUR FAR SOUTHWEST MAY EVEN
REACH 60 DEGREES ON TUESDAY. THE PASSAGE OF A COLD FRONT WILL
BRING ANOTHER SHOT OF COLDER AIR INTO THE REGION BY MIDWEEK...WITH
HIGHS ON THURSDAY AND FRIDAY ONLY EXPECTED TO MAX OUT IN THE MID
TO UPPER 30S. AFTER LOWS IN THE 40S TUESDAY NIGHT...COLDER AIR
WILL FILTER INTO THE REGION FOR A FEW DAYS. LOW TEMPERATURES
THURSDAY NIGHT COULD CONCEIVABLE FALL INTO THE MID TO UPPER TEENS
IN THE WEST TO NORTHWEST FLOW THAT WILL BECOME ESTABLISHED BEHIND
YET ANOTHER DEARLY DEPARTED COLD FRONT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 103 AM EST FRI FEB 27 2015
EXPECT SNOW SHOWERS TO CONTINUE INTO THE MORNING HOURS BUT WILL BE
ENDING FROM NORTHWEST TO SOUTHEAST. WITH THIS...THERE WILL BE IFR
TO MVFR CIGS AND VISIBILITY TO ACCOMPANY THIS ACTIVITY THROUGH
DAWN. WINDS WILL GENERALLY BE OUT OF THE NORTH WITH SOME GUSTS AT
TIMES TO 15 KNOTS BECOMING LIGHTER INTO THE DAY WITH A LESSENING
GRADIENT. BY MIDDAY...THE MVFR CIGS WILL FINALLY LIFT AND VFR
CONDITIONS SHOULD PREVAIL THROUGH THE REST OF THE TAF PERIOD.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...SHALLENBERGER
SHORT TERM...GREIF
LONG TERM...AR
AVIATION...SHALLENBERGER
AREA FORECAST DISCUSSION
NWS JACKSON KY
103 AM EST FRI FEB 27 2015
.UPDATE...
ISSUED AT 103 AM EST FRI FEB 27 2015
CURRENT CONDITIONS ACROSS EASTERN KENTUCKY FEATURE A WEAK ARCTIC
FRONT MOVING THROUGH THE AREA. ASSOCIATED WITH THE FRONT IS SOME
WEAK RETURNS SHOWING SOME FLURRIES AND SNOW SHOWERS. SOME OF THESE
SNOW SHOWERS HAVE PRODUCED A DUSTING AT MOST IN SOME AREAS WITH
SOME VISIBILITIES NEAR A MILE. THIS BAND HAS A FINE EDGE NOW
CROSSING I-64. THIS SHOULD BRING AN END TO THE ACTIVITY INTO THE
MORNING HOURS. HAVE SENT OUT SOME FRESHENED UP GRIDS TO ADDRESS
THIS AND TEMPERATURES AS THE COLDER AIR IS NOW PUSHING THROUGH THE
MIDWEST STATES AND NOW INTO KY. THOUGH NO SIGNIFICANT CHANGE WAS
MADE TO THE ZFP...THE GRIDS HAVE BEEN SENT TO THE NDFD SERVERS.
UPDATE ISSUED AT 945 PM EST THU FEB 26 2015
A DISTURBANCE IS WORKING THROUGH THE GREAT LAKES AND OH VALLEY
REGION AND IS BRINGING SOME VERY LIGHT SNOW OR FLURRIES TO THE
REGION. AWOS AND ASOS SITES OVER CENTRAL AND NORTHERN KY HAVE
REPORTED SNOW REACHING THE GROUND...BUT THE AIRMASS IS RATHER
DRY...SO VISIBILITIES AND CEILINGS HAVE NOT DROPPED ALL THAT FAR.
AT THIS POINT...PER RADAR AND SFC OBS IT APPEARS THAT THE LIGHT
SNOW OR FLURRIES IS NEARING THE SOMERSET TO JACKSON TO SANDY HOOK
LINE. ONLY ONE KY MESONET SITE IN CENTRAL KY HAS RECEIVED
MEASURABLE PRECIPITATION WITH THIS.
THE NEAR TERM MODELS SUCH AS THE HRRR CONTINUE TO HAVE THIS
DIMINISHING AS IT MOVES EAST...BUT IT SEEMS TO CLEARLY BE HOLDING
TOGETHER BETTER THAN THE HRRR IS FORECASTING. THE WINDS ARE BIT
MORE NORTHERLY THAN IDEAL FOR UPSLOPE ALTHOUGH THERE IS A BIT OF
AN UPSLOPE COMPONENT. THE CURRENT FORECAST IS MORE REFLECTIVE OF
THE MOST RECENT NAM AND GFS RUNS AS SEEMS MORE REASONABLE GIVEN
UPSTREAM TRENDS. AT THIS POINT...SLIGHT CHANCE TO CHANCE POPS
APPEAR TO REMAIN IN ORDER AND AN SPS IS ALREADY IN PLACE. SOME
LOCATIONS MAY PICK UP A QUARTER TO A HALF OF AN INCH OF FLUFF
WHILE OTHER LOCATIONS MAY ONLY GET A LIGHT DUSTING OR NOTHING AT
ALL. THE BIGGER STORY WILL BE THE COLDER AIR WORKING INTO THE
REGION LATE TONIGHT. LOWS SHOULD REACH THE UPPER SINGLE DIGITS
ABOVE ZERO NORTH...WITH UPPER TEENS NEAR THE TN BORDER. TEMPS WILL
STRUGGLE TO REACH THE MID TO UPPER 20S IN MANY LOCATIONS ON
FRIDAY...ALTHOUGH FRI NIGHT APPEARS TO BE COLDER ON AVERAGE THAN
TONIGHT.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 355 PM EST THU FEB 26 2015
19Z SFC ANALYSIS SHOWS LOW PRESSURE PASSING BY TO THE EAST WHILE A
DEEP LOW IS APPROACHING FROM THE NORTHWEST. AN ARCTIC COLD FRONT
FROM THIS IS MOVING INTO KENTUCKY AND THIS WILL SWEEP ACROSS
EASTERN KENTUCKY LATER THIS EVENING. ON REGIONAL RADAR...THE LIGHT
SNOW ASSOCIATED WITH THIS BOUNDARY IS STARTING TO SETTLE DEEPER
INTO THE STATE. EAST KENTUCKY SAW PARTLY SUNNY SKIES THIS
AFTERNOON WITH SOME LOW CLOUDS CLINGING TO OUR FAR EASTERN AREAS
WHILE HIGH CLOUDS PASSED THROUGH NORTHERN PARTS OF THE CWA. LOWER
CLOUDS ARE INBOUND FROM WESTERN AND CENTRAL KENTUCKY NOW...AHEAD
OF THAT FRONT. TEMPERATURES WERE ABLE TO SPIKE UP TO NEAR 40
DEGREES FOR MUCH OF THE AREA THIS AFTERNOON THANKS TO THE PARTIAL
SUNSHINE WHILE ONLY LOW 30S WERE ACHIEVED IN THE NORTHWEST.
DEWPOINTS REMAIN IN THE TEENS IN THE NORTHWEST WHILE LOWER AND
MIDDLE 20S ARE FOUND IN THE EAST. WINDS WERE GENERALLY FROM THE
NORTHWEST AT 5 TO 10 MPH WITH GUSTS TO 15 MPH.
THE MODELS ARE IN GOOD AGREEMENT ALOFT AS A WEAK WAVE PASSES TO
THE SOUTH OF THE AREA THIS EVENING FOLLOWED BY A STRONGER AND
LARGER TROUGH THAT SETTLES INTO THE OHIO VALLEY TONIGHT. THIS
TROUGH WILL BRING ITS CORE ENERGY ACROSS OHIO DURING THE DAY
FRIDAY BEFORE TAPERING OFF AMIDST REBOUNDING HEIGHTS OVER KENTUCKY
FRIDAY NIGHT. THE ECMWF IS A BIT QUICKER THAN THE OTHER MODELS
WITH THESE HEIGHT RISES AND MAY BE GETTING AHEAD OF ITSELF. GIVEN
THE GENERAL AGREEMENT...AT LEAST INTO FRIDAY EVENING...HAVE
FAVORED THE HIGHER RESOLUTION MODEL GUIDANCE FROM THE HRRR...
RAP13...AND NAM12 FOR WX SPECIFICS.
SENSIBLE WEATHER WILL FEATURE CLOUDS ARRIVING ALONG WITH SNOW
SHOWERS THIS EVENING AND CONTINUING THROUGH THE NIGHT IN
ASSOCIATION WITH THE ARCTIC AIR POURING BACK INTO THIS PART OF THE
STATE. TEMPERATURES WILL FALL INTO THE TEENS IN MOST PLACES BY
DAWN THANKS TO THE CAA WITH SOME SINGLE DIGITS POSSIBLE NORTH OF
INTERSTATE 64. ANY LINGERING SNOW SHOWERS WILL COME TO AN END
FRIDAY MORNING IN FAR EASTERN PARTS OF THE AREA WITH SOME SUNSHINE
POSSIBLE BY AFTERNOON...BUT TEMPERATURES WILL STILL STRUGGLE TO
MAKE IT INTO THE LOWER 20S BY MIDDAY. THIS SETS THE STAGE FOR A
VERY CHILLY NIGHT WITH SINGLE DIGITS LIKELY ON TAP FOR THE VALLEYS
AND MORE OPEN AREAS...WHILE SOME LATE ARRIVING HIGH CLOUDS AND THE
INVERSION MAY SPARE THE RIDGES THE COLDEST OF THE AIR. CANNOT RULE
OUT SOME FLURRIES ARRIVING TOWARD DAWN SATURDAY AHEAD OF THE NEXT
SYSTEM...BUT HAVE LEFT THEM OUT FOR NOW.
AGAIN USED THE CONSSHORT TO JUMP START THE T/TD/WIND GRIDS
THROUGH THE DAY FRIDAY...WITH SOME TERRAIN BASED ADJUSTMENTS MADE
AT NIGHT. AFTER THAT...USED THE SUPERBLEND TO INITIATE THE GRIDS
INTO SATURDAY MORNING WITH MINOR CHANGES. AS FOR POPS...ENDED UP
ON THE HIGH SIDE...CLOSER TO THE MET...OF RATHER LOW MOS GUIDANCE
TONIGHT...THEN SIMILAR FOR THE REST OF THE SHORT TERM.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 400 PM EST THU FEB 26 2015
BROAD MID AND UPPER LEVEL TROUGH ACROSS THE ENTIRE CONUS WILL DEEPEN
OVER THE FAR SOUTHWEST...BAJA THROUGH THE WEEKEND PLACING OUR AREA
IN A GENERAL SOUTHWEST FLOW REGIME FOR THE BULK OF THE EXTENDED.
THIS WILL TEND TO KEEP STORM TRACKS SOMEWHAT CENTERED OVER THE OHIO
VALLEY REGION AS A SERIES OF DISTURBANCES RIDE NORTHEAST ACROSS THE
EASTERN CONUS. OVERALL IT APPEARS WE WILL BE GETTING INTO A VERY
ACTIVE WEATHER PATTERN...TYPICAL FOR THE APPROACH OF EARLY SPRING.
ACTUAL SENSIBLE WEATHER...PRECIPITATION TYPES...AMOUNTS ETC. WILL
DEPEND MORE ON EXACT TRACK OF SURFACE LOWS THROUGH THE REGION.
CONSIDERING THE CURRENT SNOWPACK ALONG WITH THE WATER CONTENT
PRESENT ACROSS A LARGE PART OF THE AREA...POTENTIAL HYDRO ISSUES
WILL NEED TO BE CONSIDERED SHOULD MUCH OF ANY PRECIPITATION WE
REALIZE THROUGH THE PERIOD FALL IN THE FORM OF RAIN.
MODEL SOLUTIONS APPEAR TO BE IN FAIRLY GOOD AGREEMENT THROUGH THE
EXTENDED. A SERIES OF STORM SYSTEMS SHOOT OUT OF THE INTER-MOUNTAIN/
SOUTH CENTRAL PLAINS AREA IN RAPID FIRE FASHION THROUGH THE PERIOD.
THE FIRST SHOULD AFFECT OUR AREA SUNDAY INTO MONDAY...THE SECOND
TUESDAY THROUGH EARLY WEDNESDAY AND THEN THE THIRD LATE WEDNESDAY
NIGHT INTO THURSDAY. ATTM MODEL CONSENSUS IS FOR SFC LOWS TO TRACK
GENERALLY TO OUR NORTHWEST...KEEPING OUR AREA IN THE WARM SECTORS OF
THESE SYSTEMS. HOWEVER...THE COLDER AIR THAT FILTERS IN BEHIND EACH
PASSING SYSTEM MAY ALLOW FOR THE A WINTRY MIX AT THE ONSET OF EACH
NEW ROUND OF WEATHER. THIS MAY BE ESPECIALLY TRUE NEXT TUESDAY
MORNING. AFTER A VERY COLD START FOR FRIDAY...EXPECT TEMPERATURES TO
GRADUALLY MODERATE TOWARDS MORE NORMAL LEVELS THROUGH THE EXTENDED
THOUGH OVERALL WE WILL REMAIN BELOW NORMS FOR THIS TIME OF THE
YEAR.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 103 AM EST FRI FEB 27 2015
EXPECT SNOW SHOWERS TO CONTINUE INTO THE MORNING HOURS BUT WILL BE
ENDING FROM NORTHWEST TO SOUTHEAST. WITH THIS...THERE WILL BE IFR
TO MVFR CIGS AND VISIBILITY TO ACCOMPANY THIS ACTIVITY THROUGH
DAWN. WINDS WILL GENERALLY BE OUT OF THE NORTH WITH SOME GUSTS AT
TIMES TO 15 KNOTS BECOMING LIGHTER INTO THE DAY WITH A LESSENING
GRADIENT. BY MIDDAY...THE MVFR CIGS WILL FINALLY LIFT AND VFR
CONDITIONS SHOULD PREVAIL THROUGH THE REST OF THE TAF PERIOD.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...SHALLENBERGER
SHORT TERM...GREIF
LONG TERM...SBH
AVIATION...SHALLENBERGER
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
403 AM EST FRI FEB 27 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 402 AM EST FRI FEB 27 2015
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A NW FLOW ALOFT
OVER THE UPR GREAT LKS TO THE SW OF CLOSED H5 LO OVER NRN QUEBEC.
SHRTWV RDG AXIS STRETCHING FM THE NRN PLAINS INTO NW ONTARIO IS
SUPPORTING A SFC HI PRES STRETCHING FM THE NRN PLAINS INTO IOWA. UPR
MI IS DOMINATED BY A DRY WNW LLVL FLOW E OF THIS HI CENTER /00Z
PWATS UPSTREAM ARE GENERALLY 0.05 TO 0.10 INCH...NO MORE THAN 50 PCT
OF NORMAL/. COMBINATION OF THE DRYNESS OF THE UPSTREAM AIRMASS...00Z
INL AND YPL RAOBS SHOW AN INVERTED V T/TD PROFILE BLO SUBSIDENCE
INVRN NEAR H9...AND EXTENSIVE ICE COVER OVER LK SUP HAS GREATLY
DIMINISHED THE LES. IN FACT...IR STLT IMAGERY SHOWS ONLY PATCHY LK
CLDS STREAMING INTO AREAS E OF MUNISING. 00Z H85 TEMPS OVER THE AREA
RANGE FM -23C AT GRB TO -19C AT INL/YPL AND THEN UP TO -16C AT THE
PAS MANITOBA. UNDER THE MOCLR SKIES/DRY ARCTIC AIRMASS...TEMPS HAVE
FALLEN WELL BLO ZERO OVER THE INTERIOR AND AS LO AS -25F TO -30F AT
THE MORE SHELTERED RURAL SPOTS. WINDS ARE STIRRING A BIT MORE NEAR
LK SUP UNDER A TIGHTER PRES GRADIENT...AND SOME OF THE MORE EXPOSED
LOCATIONS THERE ARE INDICATING WIND CHILLS AS LO AS -25F.
MAIN FCST CONCERNS THRU TNGT WL BE ON TEMPS. OPTED TO ISSUE AN SPS
TO COVER WIND CHILLS NEAR ADVY CRITERIA AT THE MORE EXPOSED
LOCATIONS NEAR LK SUP THIS MRNG.
TODAY...AS SHRTWV RDG TO THE NW SLIDES TO THE SE...SFC HI PRES
CENTER IS FCST TO SHIFT TO INDIANA/ILLINOIS BY 00Z SAT. THE
COMBINATION OF ONGOING SUBSIDENCE AHEAD OF THE SHRTWV RDG AND SOME
WAA AS THE SFC-H925 FLOW BACKS TO THE WSW...IS FCST TO RAISE H85
TEMPS UP TO -16 TO -17C BY THE END OF THE DAY. GIVEN ABSENCE OF MUCH
DIURNAL CU UPSTREAM YDAY AND LARGER SCALE SUBSIDENCE/WRMG AT H85...
SUSPECT THERE WL ONLY BE SOME SCT DIURNAL CLDS OVER THE INTERIOR
THIS AFTN. AS THE FLOW BACKS...LINGERING LK CLDS/ANY FLURRIES E OF
MUNISING THIS MRNG SHOULD SHIFT OUT OVER LK SUP IN THE AFTN. WITH A
GOOD DEAL OF SUNSHINE...GOING FCST HI TEMPS RECOVERING INTO THE
TEENS APPEAR TO BE ON TRACK.
TNGT...SFC HI PRES IS FCST TO SLIDE INTO THE MID ATLANTIC STATES BY
12Z SUN...WITH STEADY WSW WIND REMAINING IN PLACE UNDER THE TIGHT
PRES GRADIENT TO THE NW OF THIS FEATURE. ALOFT...UPR MI BE UNDER
CONTINUED SUBSIDENCE AHEAD OF ANOTHER SHRTWV RDG APRCHG FM THE W.
WITH A CONTINUED SLOW WARMING OF THE H85 TEMPS...AN ABSENCE OF ANY
SGNFT LLVL MSTR INFLOW AND GENERALY ACYC NATURE OF THE W FLOW...LK
CLDS OVER THE KEWEENAW SHOULD BE SCT AT BEST. ANY LK CLDS/LES OVER
THE E HALF OF THE LK SHOULD REMAIN OFFSHORE. PWAT IS FCST TO BE AOB
0.10 INCH...SO TENDED TO GO AOB THE LO END OF GUIDANCE FOR MIN TEMPS
/AS IS OBSVD THIS MRNG/ IN AREAS AWAY FM LK SUP...WHERE A STEADIER
WIND SHOULD LIMIT THE DIURNAL TEMP DROP.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 402 AM EST FRI FEB 27 2015
SATURDAY INTO SATURDAY NIGHT...A BROAD SURFACE HIGH PRESSURE SYSTEM
OVER MUCH OF THE GREAT LAKES REGION WILL REMAIN IN PLACE THROUGH THE
DAY SATURDAY. THIS WILL KEEP FAIRLY DRY AIR IN PLACE ALLOWING MOST
AREAS OF THE U.P. TO SEE SUNNY SKIES THROUGH THE DAY SATURDAY. BY
SATURDAY NIGHT...THE HIGH PRESSURE CENTER WILL SHIFT EASTWARD
STRETCHING FROM THE NORTHEAST U.S. SOUTHWARD ALONG THE EASTERN
SEABOARD. AT THIS HAPPENS...A WEAK SURFACE TROUGH/COLD FRONT WILL
APPROACH THE AREA FROM THE WEST. OVERALL MOISTURE APPEARS TO BE
LIMITED AND FOCUSED MAINLY TO THE SOUTH OF THE U.P. THEREFORE...ONLY
EXPECTING AN INCREASE IN CLOUD COVER SATURDAY NIGHT WITH ONLY A
SMALL CHANCE OF LIGHT SNOW ACROSS THE U.P. WITH LIMITED/WEAK FORCING.
SUNDAY THROUGH MONDAY...THE SURFACE TROUGH/WEAK COLD FRONT WILL
CONTINUE TO SHIFT EASTWARD AND PASS THROUGH THE UPPER PENINSULA
THROUGH THE DAY SUNDAY. AGAIN...MOISTURE WILL BE LIMITED ALONG THE
FRONT WITH CONTINUED WEAK FORCING. ONLY LIGHT SNOW IS EXPECTED
THROUGH THE DAY SUNDAY. BEHIND THE FRONT...AN UPPER LEVEL 500MB
TROUGH IS POISED TO SWING ACROSS THE U.P. SUNDAY NIGHT. AS THIS
HAPPENS...ENOUGH MOISTURE WILL REMAIN IN PLACE WITH VERY SLIGHT
ADDITIONAL MOISTURE ADDED FROM THE ICE COVER LAKE SUPERIOR TO ALLOW
A CHANCE OF LAKE EFFECT SNOW SHOWERS TO DEVELOP FOR WEST TO
NORTHWEST WIND FAVORED LOCATIONS. DELTA T VALUES WILL BE SUFFICIENT
FOR LAKE EFFECT WITH THE TROUGH AXIS SLIDING ACROSS...BUT LAKE
EFFECT INTENSITY WILL BE LIMITED TO AREAS THAT ANY BREAKS IN THE ICE
COVER OCCURS. ANY LAKE EFFECT THAT IS ABLE TO DEVELOP SUNDAY NIGHT
WILL BE SHORT LIVED AS MUCH DRIER AIR AND HIGH PRESSURE AT THE
SURFACE AND SLIGHT RIDGING ALOFT TO PUSH INTO THE UPPER GREAT LAKES
REGION DURING THE DAY MONDAY. THIS WILL FOR MAINLY SUNNY SKIES
DURING THE DAY MONDAY.
MONDAY NIGHT THROUGH WEDNESDAY...THE AFOREMENTIONED HIGH PRESSURE
SYSTEM WILL SHIFT TO THE LOWER GREAT LAKES...THEN THE EASTERN
SEABOARD MONDAY NIGHT. THIS WILL ALLOW A MORE MOIST SOUTHERLY FLOW
TO DEVELOP ON THE BACK SIDE OF THE HIGH. AT THE SAME TIME...A LOW
PRESSURE SYSTEM IS PROGGED TO DEVELOP OVER THE FOUR CORNERS REGION
OF THE U.S. ADDITIONALLY...ANOTHER STRONGER WAVE OF ENERGY IS
PROGGED TO PUSH ACROSS CENTRAL CANADA AND WORK TOWARD THE JAMES BAY
AREA. THERE ARE MODEL DIFFERENCES WITH THE PHASING OF THE TWO
SYSTEMS. THE 18Z/26 00Z/27 GFS IS MORE PROGRESSIVE WITH BOTH
SYSTEMS AND THE PHASING OF THE SYSTEMS. THIS WOULD PUSH SNOW INTO
THE AREA AS EARLY AS MONDAY EVENING ON ISENTROPIC UPGLIDE AND
INCREASED MOISTURE IN THE AREA. THE EC 12/26 00Z/27 IS MUCH SLOWER
WITH THE PHASING...KEEPING THE PRECIPITATION OUT OF THE AREA UNTIL
LATE MONDAY NIGHT INTO TUESDAY MORNING. THE BEST CHANCES GIVEN THE
OVERLAP OF THE TWO MODEL SOLUTIONS WOULD BE TUESDAY AFTERNOON INTO
TUESDAY NIGHT...ESPECIALLY FOR THE EAST HALF OF THE U.P. AT THIS
POINT...WILL STICK WITH CHANCE POPS AT LEAST UNTIL THE SYSTEM IS
SAMPLED BETTER OVER THE NEXT FEW DAYS.
WEDNESDAY NIGHT AND THURSDAY...BOTH THE EC AND GFS AGREE ON AN UPPER
LEVEL TROUGH AXIS ALONG WITH DEEPER MOISTURE LINGERING ACROSS THE
AREA DURING THIS TIME PERIOD. THE COLDER TEMPERATURES ALOFT ALONG
WITH ANY ADDITIONAL MOISTURE OFF LAKE SUPERIOR WILL ALLOW FOR LAKE
EFFECT SNOW CHANCES. AGAIN...THE EXACT LOCATION ALONG WITH INTENSITY
WILL BE LARGELY TIED TO ANY BREAKS IN THE ICE COVER ON LAKE
SUPERIOR. THE FAVORED LOCATIONS BASED SOLELY ON WIND WOULD BE FOR
THE WEST TO WEST NORTHWEST WIND FAVORED SNOW BELTS. GENERALLY...ANY
LAKE EFFECT SNOW SHOULD REMAIN FAIRLY LIGHT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1200 AM EST FRI FEB 27 2015
WEST FLOW COMBINED WITH ICE COVERED LAKE SUPERIOR IS PROHIBITING LAKE
CLOUDS TONIGHT AT THE TAF SITES. EXPECT THIS TO CONTINUE THROUGH MUCH
OF THE TAF PD. THERE IS A CHANCE FOR SOME DIURNAL MVFR CLOUDS TO FORM
AT KSAW DURING THE DAY ON FRI.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 402 AM EST FRI FEB 27 2015
EXPECT WINDS TO BE UNDER 30 KTS THIS FORECAST PERIOD. LAKE SUPERIOR
IS MAINLY ICE COVERED THIS MORNING. ALTHOUGH SHIFTING WINDS UP TO 20
TO 25 KTS ACCOMPANYING THE PASSAGE OF DISTURBANCES THRU THE UPPER
LAKES MAY CAUSE HOLES TO OPEN IN THE ICE FROM TIME TO TIME...A
CONTINUED DOMINANCE OF ARCTIC AIR WILL MAINTAIN AN OVERALL EXTENSIVE
ICE COVER.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...KEC
AVIATION...VOSS
MARINE...KC
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
358 AM EST FRI FEB 27 2015
.SHORT TERM...TODAY AND TONIGHT
RECORD LOWS FOR FEB 27
DETROIT AREA: -4 (1934)
FLINT AREA: -14 (1994)
SAGINAW: -8 (1934)
ANOTHER COLD MORNING ACROSS SOUTHEASTERN MICHIGAN WITH AN ARCTIC
SURFACE RIDGE LOCKED IN OVERHEAD. NIL WIND AND CLEAR SKIES HAS LED
TO FAVORABLE RADIATIVE COOLING CONDITIONS. SURFACE TEMPERATURES
CURRENTLY RANGE FROM 0 TO 10 DEGREES BELOW ZERO AS OF 3AM. WITH A
LACK OF LOW CLOUD DISCERNIBLE IN IR IMAGERY...EXPECTATIONS ARE FOR
SURFACE TEMPERATURES TO CONTINUE TO BOTTOM OUT BEFORE SUNRISE WITH
MANY RURAL LOCATIONS REACHING 10 TO 20 DEGREES BELOW ZERO. WITH A
DECOUPLED SURFACE LAYER...WILL HONOR THE DECISION OF PRIOR SHIFTS
AND NOT ISSUE A WIND CHILL ADVISORY.
COLDEST MIDLEVEL TEMPERATURES PUSHING OUT OF THE STATE TODAY IN
COMBINATION WITH AN SURFACE ANTICYCLONE PUSHING INTO PORTIONS OF
OHIO WILL ALLOW WIND DIRECTIONS OVER SOUTHEASTERN MICHIGAN TO MAKE A
CONCERTED MOVE TO SOUTHWESTERLY. ENHANCED MOISTURE AND LAKE MICHIGAN
CLOUD DEBRIS IS PROGGED TO STREAM EASTWARD WITH TIME...SHOWN TO
SLIDE THROUGH PORTIONS OF THE CWA BY THIS AFTERNOON AND INTO THE
EARLY EVENING. RAP SOUNDINGS SUGGEST THERE WILL BE A CONSIDERABLE
DIURNAL COMPONENT TO ANY SKY COVER. WIND TRAJECTORIES POINT TO THE
NORTHERN CWA/SAGAINAW VALLEY AS THE MORE FAVORABLE LOCATION FOR
CLOUDS. WITH SUN...SHADED A DEGREE OR TWO HIGHER THAN MOS GUIDANCE
FOR HIGHS.
SURFACE HIGH PRESSURE PUSHING THROUGH INDIANA AND OHIO WILL SET
ANOTHER NIGHT UP FOR CALM WINDS ACROSS THE SOUTHERN HALF OF THE CWA.
LOWERED MINS FOR AREAS SOUTH OF DETROIT. OTHERWISE...A PRESSURE
GRADIENT IN PLACE OVER THE TRI CITIES/NORTHERN THUMB AND SOME
POTENTIAL FOR LINGERING CLOUDS LIMITS THE TEMPERATURE FALL POTENTIAL
FOR TONIGHT.
&&
.LONG TERM...
COLD AIRMASS WILL REMAIN IN PLACE INTO EARLY THIS WEEKEND ALTHOUGH
TEMPERATURES WILL MODERATE EVER SO SLIGHTLY AS THE LATEST ARCTIC
HIGH PRESSURE SHIFTS TO THE EAST OF THE AREA SATURDAY NIGHT. HIGHS
ON SATURDAY WILL CLIMB TO AROUND 20F WITH LOWS THAT NIGHT HOLDING
INTO THE SINGLE DIGITS TO NEAR 10F AS BOTH THE COLDEST AIR SHIFTS
EAST AND EXPANDING CLOUD COVER WORKS INTO THE AREA WITH THE APPROACH
OF A LOW PRESSURE SYSTEM.
00Z MODEL RUNS...SAVE THE NAM12...BASICALLY SUPPORT THE PREVIOUS
FORECAST AS ROUGHLY 1 TO 2 INCHES OF SNOW FALL FROM THE I-69
CORRIDOR NORTH LATE SATURDAY NIGHT INTO EARLY SUNDAY EVENING WITH 2
TO 3 INCHES SOUTH OF THAT INTO METRO DETROIT AS H7 SPECIFIC HUMIDITY
CLIMBS TO AROUND 2 G/KG ALONG THE M-59 CORRIDOR. GIVEN THE
RELATIVELY HIGH SNOW TO LIQUID RATIOS EXPECTED WITH THE COLD AIRMASS
IN PLACE...15:1 OR A BIT MORE...WOULD NOT BE SURPRISED TO SEE UP TO
4 INCHES FROM THE I-94 CORRIDOR SOUTHWARD.
TEMPERATURES WILL EDGE BACK DOWN EARLY NEXT WEEK...BUT TO MUCH MORE
REASONABLE LEVELS THAN THE PAST SEVERAL WEEKS AS HIGHS MONDAY REACH
THE MID/UPPER 20S AND LOWS HOLD IN THE TEENS SUNDAY AND MONDAY NIGHT.
THE NEXT LOW PRESSURE SYSTEM APPEARS TO BE SHAPING UP TO BE A
STRONGER SYSTEM THAN THE WEEKEND EVENT...WITH A TRACK THAT WOULD
SUPPORT A WIDE VARIETY OF PRECIPITATION ACROSS THE CWA ON TUESDAY
WITH PRIMARILY SNOW OVER THE NORTHERN CWA AND SNOW CHANGING TO A MIX
AND THEN EVENTUALLY RAIN FURTHER SOUTH. WITH THE EVENTUAL TRACK AND
STRENGTH OF THIS SYSTEM STILL IN DOUBT...WILL FORGO ANY SIGNIFICANT
DETAILS AT THIS TIME...OTHER THAN TO INCLUDE SOME MENTION OF
SLEET...FREEZING RAIN AND RAIN AS 00Z RUNS OF THE GFS...CMC AND
ECMWF DO NOT SUPPORT AN ALL SNOW EVENT FOR THE ENTIRE CWA.
&&
.MARINE...
HIGH PRESSURE WILL BE BUILD FROM THE MID MISSISSIPPI VALLEY TODAY
THROUGH THE OHIO VALLEY ON SATURDAY. MODEST SOUTHWEST RETURN FLOW
WILL DEVELOP AROUND THIS HIGH OVER THE CENTRAL GREAT LAKES. CENTRAL
SECTIONS OF LAKE HURON WILL MOST LIKELY SEE WINDS INCREASE INTO THE
15 TO 20 KNOT RANGE. OTHERWISE...WINDS WILL REMAIN ON THE LIGHT SIDE
AS THIS SOUTHWEST PRESSURE GRADIENT WEAKENS LATE IN THE WEEKEND AS A
WEAK LOW PRESSURE SYSTEM LIFTS INTO THE REGION. EVEN THE RETURN OF
COLD NORTHWEST FLOW IN THE WAKE OF THE ATTENDING COLD FRONT WILL BE
LIMITED TO 25 KNOT GUSTS OR LESS OVER MUCH OF LAKE HURON.
&&
.AVIATION...ISSUED 1153 PM EST THU FEB 26 2015
EXISTING ARCTIC HIGH PRESSURE WILL LARGELY SUSTAIN A DRY/STABLE
ENVIRONMENT INTO FRIDAY. SOME THIN POCKETS OF STRATUS NOTED
DEVELOPING IN THE VICINITY OF MBS MAY PROVIDE A BRIEF MVFR CEILING
EARLY THIS MORNING AT MBS/FNT...BUT LIMITED COVERAGE AND DURATION
WILL SUPPORT A PREVAILING VFR. A BACKING FLOW TOWARD THE WEST AND
THEN SOUTHWEST WILL SUPPORT A PERIOD OF LOW VFR DIURNAL STRATO CU
DEVELOPMENT FRIDAY AFTERNOON...GREATER COVERAGE SEEMINGLY MORE
LIKELY ACROSS THE NORTHERN TAF SITES.
//DTW THRESHOLD PROBABILITIES...
* LOW CONFIDENCE IN CEILING BELOW 5000 FT FRIDAY AFTERNOON.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&
$$
SHORT TERM...CB
LONG TERM....DG
MARINE.......DG
AVIATION.....MR
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
1104 PM MST THU FEB 26 2015
.AVIATION...
06Z TAF CYCLE
WIDESPREAD IFR TO LIFR CONDITIONS TO CONTINUE FROM CENTRAL MT
CHAIN EAST WITH MT OBSCURATIONS THROUGH MOST THIS 24 HR FCST
PERIOD...BUT SOME SLIGHT IMPROVEMENT IS POSSIBLE IN THE AFTN. ALSO
PATCHES OF -SN TO SN OVERNIGHT WILL BECOME LIGHTER AND MUCH MORE
SPOTTY AFTER DAWN. LVS/TCC WILL BE IMPACTED MOST WITH ROW ALSO
BEING IMPACTED TO SOME DEGREE. FARTHER WEST AREAS OF MVFR AND MORE
LOCALIZED IFR CIGS CAN BE EXPECTED AT LEAST INTO ROUGHLY MID MORN
FRI WITH IMPROVEMENT TO VFR YET SOME PATCHY MVFR WITH OCCASIONAL MT
OBSCURATIONS. GAP WINDS INTO RIO GRANDE VALLEY ALSO TO CONTINUE
THROUGH EARLY MORN FRI THEN DIMINISH TO SOME DEGREE. AWW TO BE
CONTINUED AT ABQ FOR NOW MORE DUE TO SN THAN WIND AS UP TO AN INCH
OR TWO OF SN TO ACCUMULATE THERE THROUGH 08Z...THOUGH SOME WIND
GUSTS STILL MAY APPROACH 30 TO 35 KT RANGE BETWEEN 07Z AND 10Z.
IFR/MVFR CIGS AND OCCASIONALLY VSBY DUE TO SN IS EXPECTED AT
ABQ/SAF/AEG MAINLY THROUGH 08 TO 09Z WITH SOME IMPROVEMENT
THEREAFTER...ESPEC AT ABQ. AEG AND SAF MAY EVEN SEE A FEW PERIODS
OF LIFR CONDITIONS DURING HEAVIER SNOW BURSTS AND THEREAFTER INTO
EARLY TO MID MORN DUE LARGELY TO FOG.
43
&&
.PREV DISCUSSION...731 PM MST THU FEB 26 2015...
.UPDATE...
NAM12 AND HRRR SHOW LARGER SNOW AMOUNTS OVER SOCCORO AND LINCOLN
COUNTY THAN EARLIER ANTICIPATED...AS UPPER JET SAGS FARTHER SOUTH
TONIGHT. LIGHT SNOW AT KONM PRESENTLY...SO DECIDED TO GO AHEAD
WTIH SOME EXPANDED WINTER WEATHER AVISORIES. UPDATED ZFP AND WSW
ALREADY OUT.
43
&&
.PREV DISCUSSION...333 PM MST THU FEB 26 2015...
.SYNOPSIS...
AN UNSETTLED WEATHER PATTERN WILL CONTINUE OVER NORTHERN AND
CENTRAL NEW MEXICO THROUGH THE NEXT SEVERAL DAYS AS NUMEROUS
DISTURBANCES ALOFT BRING PRECIPITATION TO THE STATE. TEMPERATURES
ARE CURRENTLY WELL BELOW AVERAGE...ESPECIALLY IN THE EASTERN
PLAINS OF THE STATE WHERE READINGS ARE SOME 30 DEGREES BELOW
NORMAL FOR LATE FEBRUARY. WITH COLDER AIR IN PLACE...SNOW IS
EXPECTED TO BREAK OUT OVER MUCH OF CENTRAL TO EASTERN NEW MEXICO
TONIGHT INTO FRIDAY AS AN UPPER LEVEL DISTURBANCE APPROACHES.
SEVERAL INCHES OF ADDITIONAL ACCUMULATION ARE EXPECTED BY
TOMORROW...ESPECIALLY IN THE MOUNTAINS AND HIGHLANDS OF NORTHERN
AND CENTRAL NEW MEXICO. AS THE WEEKEND UNFOLDS...ANOTHER POTENT
DISTURBANCE WILL DIVE INTO CALIFORNIA BEFORE SLOWLY SPREADING OVER
NEW MEXICO. A PROLONGED PERIOD OF HIGH ELEVATION SNOW IS EXPECTED
SATURDAY...SUNDAY...AND INTO MONDAY AND TUESDAY. THE HIGHEST SNOW
TOTALS WILL BE FOUND IN THE SAN JUAN OR TUSAS MOUNTAINS NEAR THE
COLORADO BORDER WHERE TWO TO FOUR FEET OF SNOW COULD ACCUMULATE
ABOVE TEN THOUSAND FEET. RAIN WILL FALL IN LOWER ELEVATIONS DURING
THIS WEEKEND TO EARLY NEXT WEEK PERIOD.
&&
.DISCUSSION...
IT HAS BEEN AN EXTREMELY BUSY SHIFT TODAY WITH A FOCUS ON WINTER
HIGHLIGHTS IN NOT ONLY THE NEAR TERM...BUT ALSO FOR THE NEXT
IMPENDING UPPER LOW THAT WILL BEGIN IMPACTING NM THIS WEEKEND.
SOMEWHAT OF A LULL OR RESPITE HAS BEEN OBSERVED THIS AFTERNOON
WITH REGARDS TO SNOW...BUT IT HAS NOT FULLY ENDED IN SOME OF THE
NORTHERN MOUNTAIN LOCALES. THE NEXT UPSTREAM DISTURBANCE IS
LOOKING HEALTHY ON WATER VAPOR SATELLITE IMAGERY...CURRENTLY JUST
WEST OF THE FOUR CORNERS AREA...PERHAPS A BIT FARTHER SOUTH THAN
MODELS HAVE BEEN INDICATING. THIS WILL SPREAD SUFFICIENT DYNAMICS
ALOFT TO SATURATE THE MID LEVELS OF THE ATMOSPHERE WHICH WILL THEN
SEED LOWER LEVELS AND PRODUCE SIGNIFICANT SNOW...ESPECIALLY WHERE
EAST/SOUTHEAST UPSLOPE FLOW WILL BE RUNNING UP ON THE RESPECTIVE
SLOPES OF HIGHER TERRAIN. SANGRES AND CENTRAL MOUNTAINS/HIGHLANDS
APPEAR TO BENEFIT THE MOST FROM THE UPSLOPE WHILE SATURATED MID
LEVEL CLOUD DECKS WILL SEED LOWER LAYERS...INDUCING SNOW GROWTH.
IN ADDITION THE DYNAMICS SHOULD BE ENOUGH TO PRODUCE SIGNIFICANT
SNOWFALL OVER THE HIGHER PEAKS OF THE REMAINING NORTHERN
MOUNTAINS. THE EASTERLY FLOW HAS BEEN ACCELERATING THROUGH
GAPS/CANYONS WITHIN THE CENTRAL MOUNTAIN CHAIN...AND AN EARLY
EVENING SURGE SHOULD ALLOW SPEEDS TO JUMP UP SEVERAL MPH AT KABQ
AND KSAF. THIS SHOULD SHADOW MUCH OF THE ALBUQUERQUE METRO AREA
WITH REGARD TO SNOW...SO HIGHLIGHTS WERE HEDGED ON LOWER SIDE WITH
JUST AN ADVISORY.
AS THIS EVENING`S DISTURBANCE TRACKS INTO TX ON FRIDAY...SNOW WILL
BEGIN TO TAPER OFF TOWARD MID DAY. SOME UPSLOPE WILL CONTINUE
THOUGH...KEEPING THOSE FAVORED AREAS PRECIPITATING AT LIGHT RATES.
SOME OF THE HIGHLIGHTS WILL NEED TO BE CONTINUOUSLY MONITORED TO
DECIDE ON EARLIER EXPIRATION FRIDAY. TEMPERATURES WILL BE EVEN
COLDER IN MOST ZONES ON FRIDAY AS THE SYNOPTIC COLD POOL CONTINUES
SEEPING WESTWARD. THIS WILL PUT MOST ZONES AT 10 TO 40 DEGREES
BELOW NORMAL FRIDAY AFTERNOON. INTERESTINGLY MODELS BREAK OUT NEW
BATCHES OF PRECIPITATION IN THE NORTHWESTERN QUADRANT OF THE STATE
FRIDAY AFTERNOON. WITHOUT THE PRESENCE OF ANY BLATANT PERTURBATION
IMMEDIATELY UPSTREAM...IT APPEARS THE TRIGGER IS SOME DIVERGENCE
ALOFT...ASSOCIATED WITH JET DYNAMICS FAR AHEAD OF THE NEXT TROUGH
DIVING INTO THE GREAT BASIN. HAVE INCREASED POPS SOME TO REFLECT
HIGHER PROBABILITIES IN THE NORTHWESTERN ZONES...BUT MAY NOT HAVE
RAISED ENOUGH.
CONFIDENCE IS HIGHER IN THE ELEVATED PROBABILITIES OVER
NORTHWESTERN TO WEST CENTRAL NM FRIDAY NIGHT AND SATURDAY AS THE
AFOREMENTIONED TROUGH DIVES SOUTHWARD OVER CALIFORNIA AND DEEPENS
INTO A LOW...SHEDDING ENERGY INTO AZ/NM. THIS WILL BRING A
STIFFENING SOUTHWESTERLY FLOW OVER NM THAT WOULD HAVE GOOD
OROGRAPHICS ASSOCIATED WITH IT WHILE ALSO ACTING AS A WARM
ADVECTION CATALYST. HAVE OPTED TO ISSUE WINTER STORM WATCH FOR THE
SAN JUAN/TUSAS AND JEMEZ ZONES STARTING FRIDAY NIGHT AND RUNNING
INTO SUNDAY. QPF AMOUNTS ARE VERY IMPRESSIVE WITH THIS FEATURE
FRIDAY NIGHT THROUGH SUNDAY. CHALLENGES WILL ARISE FROM THE WARM
ADVECTION...INDUCING RISING SNOW LEVELS AND COMPLICATING THE SNOW
RATIOS. AT THIS POINT IT STILL APPEARS 2 TO 4 FEET OF NEW SNOW
WOULD BE REASONABLE IN THIS SCENARIO NEAR THE CO-NM BORDER ABOVE
10KFT. SNOW LEVELS WOULD LIKELY RISE TO NEAR 8000 TO 8500 FEET
SUNDAY...AND WHILE THIS MIGHT SUGGEST A LIMITING OF ACCUMULATIONS
AND IMPACTS...THE HYDROLOGY IMPACTS WILL HAVE TO BE STRONGLY
CONSIDERED. IF HEALTHY RAINFALL OCCURS OVER SOME OF THE SNOW
PACK...IN THE 7000 TO 9000 FT RANGE...SOME SUBSTANTIAL MELT AND
RUNOFF COULD OCCUR. WILL MONITOR THIS SCENARIO CLOSELY THE NEXT
COUPLE OF DAYS.
AS THE CA LOW FINALLY DRAGS NORTHEASTWARD OVER NM MONDAY AND
MONDAY NIGHT...ANOTHER PERTURBATION WILL DROP DOWN ON ITS HEELS
TUESDAY...FOLLOWED BY ANOTHER ON WEDNESDAY. THE WEDNESDAY FEATURE
COULD ALLOW A VERY COLD DOME TO SPILL SOUTHWARD INTO NM...BUT IT
WOULD APPEAR TO BE THE CABOOSE ON THE RECENT STORM TRAIN.
52
&&
.FIRE WEATHER...
NO FIRE WEATHER CONCERNS NEXT SEVERAL DAYS. THE ACTIVE WINTER
WEATHER PATTERN WILL CONTINUE THROUGH MIDDLE OF NEXT AS A SERIES
OF UPPER LEVEL DISTURBANCES CROSS OVER THE STATE. TEMPS AREAWIDE
WILL REMAIN BELOW NORMAL THROUGH WEDNESDAY WITH UNUSUALLY HIGH
HUMIDITY.
GUSTY GAP WINDS WILL CONTINUE ALONG THE CENTRAL MOUNTAINS FOR THE
NEXT 24-48 HOURS. OTHERWISE...ANOTHER ROUND OF WETTING SNOW WILL
DEVELOP AND FAVOR CENTRAL/EASTERN AREAS TONIGHT INTO FRIDAY
MORNING. SNOW SHOWERS SHOULD CONTINUE ACROSS WESTERN/CENTRAL AREAS
FRIDAY AFTERNOON.
WETTING PRECIPITATION WILL THEN BE CONFINED TO OVER NORTHERN AND
WESTERN AREAS THIS WEEKEND. SNOW LEVELS WILL RISE DURING THIS PERIOD
AS THE ATMOSPHERE WARMS. MODELS HAVE BEEN TRENDING TOWARDS MORE OF
AN UPPER LEVEL DRY SLOT IMPACT SOUTH CENTRAL/SOUTHEAST AREAS DURING
THIS SAME PERIOD. TEMPERATURES WILL MODIFY SOME BUT WILL REMAIN
BELOW NORMAL. BREEZY CONDITIONS ARE EXPECTED ACROSS WESTERN/CENTRAL
AREAS ESPECIALLY FAVORING THE HIGH TERRAIN. WINDY CONDITIONS ARE
VERY POSSIBLE ACROSS THE HIGH TERRAIN AS THE FLOW ALOFT INCREASES.
MORE UPPER LEVEL DISTURBANCES FROM THE WEST WILL FOLLOW MONDAY THRU
WEDNESDAY BRINGING MORE RAIN/SNOW SHOWERS TO WESTERN AND CENTRAL
AREAS. EASTERN AREAS SHOULD GET INTO THE ACTION BY MIDWEEK. TEMPS
WILL BE A BIT WARMER IN THE EAST...COOLER IN THE WEST ON MONDAY AND
TUESDAY..THEN COOLING ALL OVER WEDNESDAY.
VENTILATION IS EXPECTED TO LOWER ON FRIDAY DUE TO LOWER MIXING
HEIGHTS AND IMPACTS FROM THE BACK DOOR COLD PUSH. VENTILATION WILL
IMPROVE AS THE WEEKEND PROGRESSES...ESPECIALLY ON SUNDAY. GOOD TO
EXCELLENT VENT RATES ARE EXPECTED EARLY NEXT WEEK AS THE ATMOSPHERE
REMAINS UNSETTLED AND HIGHER TRANSPORT WINDS EXIST.
50
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL NOON MST FRIDAY FOR THE FOLLOWING
ZONES...NMZ504-507-508-520-524>526-530-533>540.
WINTER STORM WARNING UNTIL NOON MST FRIDAY FOR THE FOLLOWING
ZONES...NMZ512>516-527>529-531-532.
WINTER WEATHER ADVISORY UNTIL 5 PM MST FRIDAY FOR THE FOLLOWING
ZONES...NMZ517-519.
WINTER STORM WARNING UNTIL 5 PM MST FRIDAY FOR THE FOLLOWING
ZONES...NMZ510-511-518-521>523.
WINTER STORM WATCH FROM LATE FRIDAY NIGHT THROUGH SUNDAY AFTERNOON
FOR THE FOLLOWING ZONES...NMZ510-511.
&&
$$
AREA FORECAST DISCUSSION
NWS BROWNSVILLE TX
254 AM CST FRI FEB 27 2015
.SHORT TERM /NOW THROUGH SATURDAY/...A COLD FRONT IS WORKING ITS
WAY THROUGH THE CWA THIS MORNING...WITHOUT TOO MUCH FANFARE.
SOUTHERN EDGE AND RR QUAD OF AN UPPER JET STREAK RESULTED IN A
RIBBON OF UPPER CLOUDS STILL OVER THE SOUTHEASTERN CORNER OF THE
CWA BUT THAT SHOULD FADE TODAY AS THICKER LOW CLOUDS TAKE OVER.
LOW CLOUDS ARE THICKENING FROM WEST TO EAST. NORTHEAST WINDS THAT
WERE ALREADY IN PLACE ARE RECEIVING SOME REINFORCEMENT AND DEW
POINTS ARE DECREASING BEHIND THE FRONT. LOOKING FOR A
COOL...CLOUDY DAY ACROSS DEEP SOUTH TEXAS AND THE RGV TODAY WITH A
RANGE OF HIGH TEMPS FROM THE UPPER 40S FAR WEST AND NORTH TO THE
LOWER 60S FOR CAMERON AND WILLACY COUNTIES. LIGHT RAIN AND DRIZZLE
CHANCES WILL INCREASE LATER TODAY AND TONIGHT AS THE COOLER AIR
BECOMES ESTABLISHED. LOW TEMPS TONIGHT WILL BE MAINLY IN THE 40S
AND 50S WITH LIGHT WINDS AS HIGH PRESSURE SPREADS OVER THE AREA.
LOOKS LIKE THE HIGH PRESSURE WILL THEN SHIFT EAST IN SHORT ORDER.
WINDS WILL VEER TO EAST BY SATURDAY AND THE RETURN FLOW WILL
SUPPORT HIGH TEMPS IN THE 60S...THOUGH AMPLE CLOUD COVER WILL
CONTINUE AND A MID LEVEL FLOW THAT WILL BACK FROM WEST TO
SOUTHWEST WILL HELP ENSURE THAT OVERRUNNING PERSISTS.
.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...OVERRUNNING LIGHT
RAIN CHANCES ACROSS DEEP SOUTH TEXAS AND THE RGV WILL COME TO AN
END SUNDAY AS COASTAL TROUGHING WEAKENS AND A WARM FRONT LIFTS
NORTHWARD. WINDS BECOME SOUTHEASTERLY BY SUNDAY MORNING AND
MOISTURE DECREASES. COLD AIR IS SHUNTED NORTH AND EAST FOR THE
START OF THE WORK WEEK WITH 850MB TEMPERATURES RISING FROM 13C
SUNDAY MORNING TO 22C BY TUESDAY NIGHT. 700MB SOUTHWESTERLIES
SPREAD OVER THE AREA BEGINNING MONDAY NIGHT. WHAT THIS MEANS IS
HIGH TEMPERATURES MONDAY AND TUESDAY WILL BE IN THE 80S WITH LOW
90S OUT WEST WHERE MID LEVEL DRY AIR DUE TO THOSE AFOREMENTIONED
SOUTHWESTERLIES WILL BE MIXED DOWN.
AN UPPER TROF WILL MOVE OVER THE WESTERN CONUS AND FOUR CORNERS
THROUGH TUESDAY. PRESSURE FALLS AHEAD OF THIS FEATURE WILL INDUCE
LEE TROUGHING ACROSS THE ROCKIES SOUTHWARD INTO THE SIERRA MADRES.
THIS WILL HELP RATCHET UP THE SOUTHERLY SURFACE WINDS MONDAY AND
TUESDAY AS WELL. SURFACE LOW PRESSURE WILL HEAD OUT OF THE HIGH
PLAINS TUESDAY AND DRAG A COLD FRONT INTO CENTRAL AND SOUTHERN
TEXAS WEDNESDAY. WIDESPREAD STRATUS ON A 40KT LOW LEVEL JET WILL
KEEP THE AREA MOSTLY CLOUDY THROUGH THE DAY WHICH WILL HOLD HIGH
TEMPERATURES DOWN INTO THE LOW 80S. TIMING DIFFERENCES EXIST
BETWEEN THE GFS/ECMWF CONCERNING THE PASSAGE OF THE FRONT WITH GFS
A LITTLE FASTER BRINGING THE FRONT THROUGH WEDNESDAY AND THE ECMWF
AT WEDNESDAY NIGHT AND THURSDAY. DESPITE THE TIMING DIFFERENCES
EXPECT STRONG NORTHERLY WINDS AND COOLER TEMPERATURES TO ROUND OUT
THE WORK WEEK. AS FAR AS POPS GO ASSOCIATED WITH THE FRONT LOOKS
LIKE CAPPING WILL BE STRONG AND LIMIT MOST PRECIPITATION TO WELL
OFFSHORE. BOTH ECMWF AND GFS HINT AT WEAK COASTAL TROUGHING FRIDAY
WITH A SLIGHT CHANCE FOR LIGHT RAIN ALONG AND EAST OF HWY 77.
&&
.MARINE /NOW THROUGH THROUGH SATURDAY/...STRONG HIGH PRESSURE
OVER THE PLAINS WILL EXTEND SOUTH OVER THE NORTH GULF AND WILL SET
UP MDT TO FRESH EAST NORTHEAST WINDS...BUT PERHAPS OF MORE
SIGNIFICANCE WILL BE THE LONG FETCH ACROSS THE NORTH GULF...WHICH
WILL SUPPORT ELEVATED SEAS DUE TO A SWELL COMPONENT. THE ONGOING
SMALL CRAFT ADVISORY FOR THE GULF WILL THUS PERSIST THROUGH THE
SHORT TERM. WAVE HEIGHTS OF 7 TO 9 FEET WILL PERSIST ON THE OPEN
GULF THROUGH SATURDAY AND INTO THE LONG TERM.
SATURDAY NIGHT THROUGH TUESDAY...MODERATE TO STRONG EAST WINDS
SATURDAY NIGHT WILL WEAKEN AND TURN MORE SOUTHEASTERLY SUNDAY AS A
WARM FRONT MOVES NORTHWARD THROUGH THE COASTAL WATERS. SMALL CRAFT
ADVISORIES WILL BE ONGOING INTO THE LONG TERM AND WILL BE NEED
THROUGH SUNDAY AS SEA HEIGHTS WILL REMAIN AROUND 7 FEET THROUGH
SUNDAY AFTERNOON. WINDS AND SEAS BECOME MORE MODERATE MONDAY WITH
CONDITIONS DETERIORATING MONDAY NIGHT AND TUESDAY AS LOW PRESSURE
DEEPENS TO OUR WEST AND SOUTHEASTERLY WINDS STRENGTHEN. SMALL
CRAFT ADVISORIES WILL BE LIKELY MONDAY NIGHT INTO TUESDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL 63 55 69 64 / 30 40 40 30
BROWNSVILLE 63 53 70 64 / 30 40 30 30
HARLINGEN 61 53 70 63 / 40 40 40 30
MCALLEN 56 50 70 62 / 30 30 20 20
RIO GRANDE CITY 51 46 68 60 / 30 50 30 20
SOUTH PADRE ISLAND 63 56 69 65 / 30 40 40 30
&&
.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 3 AM CST SATURDAY FOR GMZ150-155-170-
175.
&&
$$
THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV
SHORT TERM...54
LONG TERM...55
GRAPHICS/UPPER-AIR...61
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1025 AM EST FRI FEB 27 2015
.UPDATE...
NEAR TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 303 AM EST FRI FEB 27 2015
HIGH PRESSURE IS EXPECTED ACROSS THE AREA THROUGH SATURDAY. A
FRONTAL SYSTEM IS EXPECTED TO MOVES THROUGH THE AREA FRONT SATURDAY
NIGHT INTO SUNDAY NIGHT. A STRONGER LOW PRESSURE SYSTEM MAY AFFECT
THE AREA TOWARDS THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 1025 AM EST FRI FEB 27 2015
CANCELLED WIND CHILL ADVISORY AS WIND CHILLS ARE NO LONGER REACHING
ADVISORY CRITERIA.
OTHERWISE...SATELLITE INDICATES MOSTLY CLEAR SKIES WERE ACROSS MOST
OF THE AREA. RUC MODEL SOUNDINGS INDICATE CU MAY INCREASE THIS
AFTERNOON CAUSING SKIES TO BECOME PARTLY CLOUDY.
RUC SOUNDINGS INDICATE HIGHS FROM MIDDLE TEENS NORTH TO AROUND 20
SOUTH WHICH IS CLOSE TO CURRENT FORECAST AND A LITTLE WARMER THAN
MOST MOS GUIDANCE. THIS SEEMS REASONABLE. THERE SHOULD BE A LOT OF
SUNSHINE AT LEAST THROUGH MID DAY AND THEN A LITTLE MORE CLOUDINESS
THIS AFTERNOON. REST OF NEAR TERM SEEMS TO BE ON TRACK.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
ISSUED AT 303 AM EST FRI FEB 27 2015
DRY CONDITIONS EXPECTED TONIGHT AND SATURDAY AS SURFACE HIGH
PRESSURE GRADUALLY SHIFTS OFF TO THE EAST. MAIN ITEM OF INTEREST
DURING THIS PERIOD IS A SHORT WAVE TROUGH THAT IS EXPECTED TO DROP
SOUTHEAST ACROSS THE GREAT LAKES SUNDAY NIGHT. THE SURFACE
REFLECTION ASSOCIATED WITH THIS FEATURE DOESN/T LOOK TOO
IMPRESSIVE...BUT MODELS SUGGEST A 40 KT LOW LEVEL JET ASSOCIATED
WITH THIS FEATURE...WHICH SHOULD PROVIDE QUITE A BIT OF LIFT.
WILL BRING IN HIGH POPS BY LATE SATURDAY NIGHT AND SUNDAY BASED ON
ABOVE REASONING...WITH POPS TAPERING OFF SUNDAY NIGHT AS MAIN LIFT
PUSHES OFF TO THE EAST. OPERATIONAL MODELS SUGGEST MAINLY SNOW OVER
ABOUT THE NORTHERN HALF OF THE FORECAST AREA...WITH MORE OF A MIX
OVER THE SOUTHERN HALF...WHICH GOES ALONG WITH THE PREVIOUS
FORECAST. HOWEVER...THE ENSEMBLES SUGGEST A STRONGER PUSH OF WARM
AIR IS POSSIBLE...WITH POTENTIAL FOR RAIN AS FAR NORTH AS THE
NORTHERN ZONES BY SUNDAY. CAN/T RULE OUT THESE SOLUTIONS GIVEN THE
STRENGTH OF THE LOW LEVEL JET. FOR NOW...WILL STICK WITH THE
PREVIOUS FORECAST REGARDING PRECIPITATION TYPES AND MONITOR THE
TRENDS. SEVERAL INCHES OF SNOW ARE POSSIBLE WITH THIS
SYSTEM...ESPECIALLY OVER THE NORTHERN ZONES.
BASED ON LOW LEVEL THICKNESSES...THE GFS MOS TEMPERATURE GUIDANCE
FOR TONIGHT AND SATURDAY LOOK A LITTLE COLD. WILL BUMP UP THE
GUIDANCE A FEW DEGREES IN THOSE PERIODS. THE GUIDANCE HIGHS ON
SUNDAY LOOK TOO WARM CONSIDERING EXPECTED PRECIPITATION...SO WILL
NUDGE THOSE NUMBERS DOWN ABOUT A CATEGORY.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
ISSUED AT 258 AM EST FRI FEB 27 2015
ACTIVE PATTERN CONTINUES THROUGH THE FIRST HALF OF NEXT WEEK AS
PIECES OF ENERGY ALOFT EJECT OUT OF THE TROUGH OVER THE WESTERN U S
FOLLOWED BY THE TROUGH AXIS ITSELF MOVING EAST INTO THE REGION BY
THE END OF THE PERIOD. HIGH CONFIDENCE IN A SIGNIFICANT WEATHER
IMPACT FOR CENTRAL INDIANA AND THE OHIO VALLEY MONDAY NIGHT THROUGH
WEDNESDAY.
STRONG HIGH PRESSURE ARRIVES IN THE WAKE OF THE LATE WEEKEND SYSTEM
FOR MONDAY...AND SHOULD SERVE TO GIVE THE REGION A BREATHER BETWEEN
WEATHER SYSTEMS ON THE ORDER OF 18 TO 24 HOURS. SURFACE WAVE SET
TO SPIN UP OVER THE CENTRAL ROCKIES MONDAY NIGHT AS ENERGY EJECTS
OUT FROM THE PARENT TROUGH. THIS FEATURE WILL SWING E/NE AND TRACK
QUICKLY INTO THE REGION BY TUESDAY EVENING AND BRING WITH IT A
PLETHORA OF MESSY PROBLEMS FOR CENTRAL INDIANA. RIDGING DEVELOPING
DOWNSTREAM OF THE TROUGH SUPPORTS MORE AMPLIFIED FLOW WITH THE
SURFACE WAVE TRACKING THROUGH OR NORTH OF THE FORECAST AREA. OP GFS
SHOWING ITS USUAL PROGRESSIVE BIAS IN THE MID RANGE IN BRINGING
PRECIP IN TOO QUICKLY...ESPECIALLY CONSIDERING THE STRENGTH OF THE
DEPARTING HIGH. LIKE THE LOOK OF THE ECMWF/GGEM WHICH DELAYS MOST
PRECIP UNTIL AFTER MIDNIGHT MONDAY NIGHT.
WARM ADVECTION WILL ALREADY BE ONGOING WHEN PRECIP STARTS...AND
EXPECT PRECIP TYPE ISSUES FROM THE GET GO WITH A GROWING LIKELIHOOD
THAT FREEZING RAIN IS THE PREDOMINANT PRECIP TYPE INTO TUESDAY
MORNING. THE REFRESHED SNOWPACK COURTESY OF THE WEEKEND STORM WILL
BE A SIGNIFICANT FACTOR IN DURATION OF FROZEN PRECIP AS THE NEAR
SURFACE/GROUND TEMPS WILL LAG THE LOW LEVEL TEMP RISES. MODEL
THERMAL PROFILES ARE ALREADY SUGGESTIVE THAT IT MAY TAKE UNTIL
MIDDAY TUESDAY IN SOME PORTIONS OF THE REGION TO WARM SUFFICIENTLY
FOR ALL RAIN. IF THE IMPACT OF THE SNOWCOVER IS UNDERMINED BY THE
MODELS WHATSOEVER...THE ICING POTENTIAL COULD BE EVEN MORE
SIGNIFICANT. DO NOT EXPECT TO HAVE A GOOD HANDLE ON THIS UNTIL LATER
IN THE WEEKEND.
WHILE THE ICING THREAT IS A GROWING ISSUE...AN EXTENDED PERIOD OF
HEAVY RAIN OVER A FROZEN GROUND AND SNOW COVER POSES EVEN GREATER
CONCERNS. COPIOUS AMOUNTS OF MOISTURE WILL BE DRAWN NORTH INTO THE
REGION AHEAD OF THE APPROACHING SURFACE WAVE TUESDAY AND TUESDAY
NIGHT. PRECIP WATER VALUES ARE PARTICULARLY ALARMING...MAXING OUT
BETWEEN 1.25 AND 1.50 INCHES TUESDAY EVENING. THESE LEVELS WOULD
PLACE THE REGION NEAR AND ABOVE THE 99TH PERCENTILE FOR
CLIMATOLOGICAL PRECIP WATER VALUES IN MARCH. POTENTIAL FOR
CONVECTIVE ELEMENTS TO THE PRECIP AS WELL AND MAY NEED TO ADD AN
ISOLATED THUNDER MENTION INTO THE FORECAST FOR TUESDAY
AFTERNOON/NIGHT. 1-2 INCHES OF RAINFALL CERTAINLY LOOK PLAUSIBLE AND
WITH MOST OF THIS BEING CONVERTED TO PURE RUNOFF WITH THE FROZEN
GROUND...FLOODING CONCERNS ARE VALID. FRONTAL BOUNDARY SHOULD
FINALLY MOVE EAST WEDNESDAY WITH PRECIP ENDING LATE DAY...LIKELY AS
A RAIN/SNOW MIX. MUCH COLDER AIR WILL THEN RETURN FOR THE END OF THE
WEEK.
STILL PLENTY TO HASH OUT AND THE WEEKEND WINTER STORM WILL HAVE SOME
SAY IN HOW THIS ALL TRANSPIRES. AS STATED ABOVE THOUGH...CONFIDENCE
IS HIGH IN SIGNIFICANT WEATHER IMPACTS FOR CENTRAL INDIANA MONDAY
NIGHT THROUGH WEDNESDAY...WITH ICING...HEAVY RAIN AND FLOODING ALL
POTENTIAL CONCERNS. ENCOURAGE HOOSIERS TO STAY ABREAST OF THE
FORECAST OVER THE NEXT FEW DAYS.
&&
.AVIATION /DISCUSSION FOR 271500Z TAF UPDATE/...
ISSUED AT 920 AM EST FRI FEB 27 2015
ONLY TWEAKED KIND WIND DIRECTION. STILL SOME UNCERTAINTY ON WHERE
BROKEN CUMULUS FIELD WILL SET UP...SO LEFT FORECAST ALONE FOR NOW.
PREVIOUS DISCUSSION FOLLOWS...
VFR CONDITIONS EXPECTED THROUGHOUT THE FORECAST PERIOD.
HIGH PRESSURE WILL BUILD ACROSS THE OHIO VALLEY TODAY WITH PARTLY
CLOUDY SKIES. POCKETS OF STRATOCU CONTINUE TO DROP INTO CENTRAL
INDIANA WITH LOW LEVEL FLOW OFF LAKE MICHIGAN. DESPITE THE DRIER
AIR AND SUBSIDENCE OVERSPREADING THE REGION TODAY...COLD POOL
ALOFT AND PRESENCE OF 850MB THERMAL TROUGH BOTH SUPPORT RENEWED CU
DEVELOPMENT FOR THE AFTERNOON...ESPECIALLY AT KBMG AND KIND.
AS CU SCATTERS OUT LATER THIS AFTERNOON...MID AND HIGH LEVEL
CLOUDS WILL INCREASE FROM THE SOUTHWEST FOR TONIGHT IN ADVANCE OF
A SYSTEM DEVELOPING OVER THE SOUTHERN PLAINS. SKIES WILL BECOME
OVERCAST AFTER MIDNIGHT AS CEILINGS LOWER TO 8-10KFT. NORTHWEST
WINDS AT 5-10KTS TODAY WILL EVENTUALLY BECOME LIGHT AND VARIABLE
OVERNIGHT.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
IND...NONE.
&&
$$
SYNOPSIS...JAS
NEAR TERM...JH
SHORT TERM...JAS
LONG TERM....RYAN
AVIATION...RYAN/50
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSINDIANAPOLIS
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION...UPDATED
NWS QUAD CITIES IA IL
725 AM CST FRI FEB 27 2015
.UPDATE...
ISSUED AT 721 AM CST FRI FEB 27 2015
RECORD LOW COLD TEMPERATURES OCCURRED TONIGHT WITH THE CLEAR SKIES
AND FRESH SNOWFALL. WIND CHILLS IN A FEW LOCATIONS WERE BELOW -30.
THE ONLY CHANGE TO THE FORECAST WERE THE TEMP TRENDS. EXPECT A
WARM UP ONCE THE SUN STARTS HEATING AS IT IS STARTING TO BECOME THE
SEASON OF HIGHER SUN ANGLES. WIND CHILL ADVISORY SHOULD STILL BE
OKAY THROUGH 9AM...A FEW SITES MAY LINGER WITH SUB -20 WIND CHILLS
THROUGH 10AM.
&&
.SYNOPSIS...
ISSUED AT 307 AM CST FRI FEB 27 2015
HIGH PRESSURE WAS MOVING INTO THE CENTRAL PLAINS EARLY THIS
MORNING. WITH FRESH SNOWFALL AND CLEAR SKIES TEMPERATURES HAVE
PLUMMETED THIS MORNING TO QUITE POSSIBLY ONE OF THE COLDEST NIGHTS
OF THE YEAR. WINDS HAVE STAYED UP...WHICH HAS LEAD TO WIDESPREAD
WIND CHILLS BETWEEN 20 AND 30 BELOW ZERO WITH A FEW POCKETS OF 30
BELOW OR LOWER WIND CHILLS. WINDS ARE STARTING TO WANE AND
TEMPERATURES SHOULD DROP MORE.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 307 AM CST FRI FEB 27 2015
MAIN FORECAST CONCERN FOR THE SHORT TERM ARE TEMPERATURES TODAY
AND TONIGHT ACROSS THE AREA. WITH HIGH PRESSURE IN PLACE AND FRESH
SNOW COVER...GUIDANCE IS OF LITTLE HELP FOR TEMPERATURE FORECASTS.
AS FAR AS THE SYNOPTIC PATTERN IS CONCERNED...H5 RIDGING IS
BUILDING INTO THE CENTRAL UNITED STATES AS A SURFACE HIGH IS PROG
TO MOVE DIRECTLY OVER OUR CWA TODAY. WINDS SHOULD WANE...HOWEVER
COLD AIR AND FRESH SNOWFALL WILL LEAD TO COLD TEMPERATURES TODAY
AND TONIGHT. MODELS ARE OF LITTLE HELP...THIS MORNING FOR LOWS I
LOADED THE OBS AND THEN MADE TWEAKS FROM THERE AS THE RUC WAS THE
ONLY MODEL COLD ENOUGH WITH TEMPS. FOR TODAY AND TONIGHT...WENT
WITH THE ALLBLEND AND THEN TWEAKED TEMPERATURES FROM THERE. WIND
CHILLS TONIGHT SUGGEST THE NEED FOR ANOTHER WIND CHILL ADVISORY
FOR AREAS NORTH OF I80. WILL DEFER TO THE DAY TO SHIFT TO DECIDE
TO ISSUE THIS AS THERE IS ALREADY ONE OUT.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 307 AM CST FRI FEB 27 2015
TWO STORM SYSTEMS WILL IMPACT THE EXTENDED FORECAST...AND BOTH
CONTAIN POTENTIAL WINTER IMPACTS. AT THIS TIME...BOTH SYSTEMS ARE
RELATIVELY POOR IN CONFIDENCE OF EXACT DETAILS CONCERNING THESE
IMPACTS.
TO BEGIN THE EXTENDED...HIGH PRESSURE WILL BE MOVING OFF TO THE EAST
SATURDAY...AND WITH A VERY COLD START TO THE DAY...THE WEAK WAA WILL
LIKELY ONLY RESULT IN HIGHS IN THE MID TEENS NORTH TO MID 20S
SOUTH...DESPITE A HEALTHY AMOUNT OF LATE FEBRUARY SUNSHINE IN THE
MORNING. WARM ADVECTION BY AFTERNOON...WILL BRING MID LEVEL MOISTURE
NORTHWARD...WITH SOME MODELS CONTINUING TO BRUSH OUR SOUTHWEST WITH
DEEPER SATURATION BY LATE AFTERNOON. THE MODEL BLEND SHOWS FAR MORE
SIGNIFICANT MOISTURE ADVECTION BY SATURDAY NIGHT...AND I WILL
CONTINUE TO HIGHLIGHT THAT PERIOD THROUGH SUNDAY WITH HIGH POPS.
THIS EVENT IS GOING TO BE ALL SNOW...AND SHOULD HAVE RATIOS IN THE
12 TO 15 TO 1 RANGE...THUS AMOUNTS FROM SATURDAY EVENING THROUGH
SUNDAY AFTERNOON SHOULD RANGE FROM AROUND 1 INCH NORTHWEST...TO 2 TO
3 INCHES FROM IOWA CITY THROUGH THE QUAD CITIES TO STERLING...TO 3
TO 5 INCHES OVER FAR SOUTHEAST IOWA NORTHEAST MISSOURI TO NEAR
PRINCETON ILLINOIS. WHILE THOSE AMOUNTS ARE SUPPORTED BY THE MOST
LIKELY BLEND OF GUIDANCE THAT IS INDICATED AT THIS TIME...I AM NOT
CONFIDENT IN THEM YET. THE EVENT IS LIKELY GOING TO FALL INTO THE
ADVISORY RANGE...ESPECIALLY DUE TO THE LONGER THAN NORMAL DURATION
FOR THESE RANGE OF AMOUNTS. LOOKING AT UNCERTAINTY...THE CANADIAN
MODEL IS FARTHER SOUTH THAN THE ECMWF AND GFS...AND KEEPS THE
NORTHERN 3/4S OF THE CWA DRY...THUS ANOTHER REASON FOR HOLDING OFF
ON ANY EARLY HEADLINE AT THIS TIME. THE 06Z NAM...THROUGH 12Z
SUNDAY...ALSO KEEPS THE BULK OF MOISTURE AND FORCING SOUTH.
MONDAY WILL BE A BREAK BETWEEN LOW CONFIDENCE SYSTEM...AS THE DEEP
WESTERN TROF BECOMES EVEN MORE AMPLIFIED. THE MODELS HAVE SHOWN VERY
LITTLE CONSISTENCY OVER THE PAST FEW DAYS AND THROUGH TONIGHT WITH
RESPECT TO THE LOW TRACK...UPPER ENERGY TRACK...AND BAROCLINICITY OF
THIS POTENTIAL SYSTEM. ONE FEATURE THAT HAS BEEN SHOWN
CONSISTENTLY...HAS BEEN MOISTURE...WITH A SYNOPTIC SIGNAL OF AN OPEN
GULF OF MEXICO...AND EVEN OPEN CARIBBEAN. THE HIGH AMOUNTS OF
AVAILABLE MOISTURE ARE REASONS SUPPORTING LIKELY POPS MONDAY NIGHT
AND TUESDAY. WHILE NOT CONFIDENT IN THERMAL TRANSITION TIMING...IT
IS A BEST MODEL BLEND...AND CONCEPTUAL MODEL FIT FOR PCPN TO BEGIN
AS A WINTRY MIX OF SNOW/SLEET/FREEZING RAIN MONDAY
NIGHT...TRANSITIONING TO RAIN TUESDAY...THEN BACK TO SNOW AGAIN
TUESDAY NIGHT. THIS WET MESS COULD BE HIGH IMPACT...OR COULD BE
LARGELY BENIGN. IT IS VERY DIFFICULT TO TELL...AND WILL KEEP A
HEALTHY DOSE OF UNCERTAINTY IN OUR PRODUCTS.
FOLLOWING THIS SYSTEM...COLDER DRY WEATHER SETTLES BACK IN THE A FEW
DAYS BEFORE MODERATION LOOKS TO OCCUR IN ZONAL FLOW.
ERVIN
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 544 AM CST FRI FEB 27 2015
VFR CONDITIONS THROUGH THE PERIOD WITH LIGHT WINDS AS HIGH
PRESSURE SETTLES OVER THE AREA. WINDS SHOULD FAVOR W TO NW TODAY
AND THEN FAVOR S TO SE OVERNIGHT. OVERALL WINDS WILL BE VERY
LIGHT. ONLY CONCERN WOULD BE FRIGID TEMPERATURES TODAY AND
TONIGHT.
&&
.CLIMATE...
ISSUED AT 307 AM CST FRI FEB 27 2015
COULD SEE RECORD LOWS THIS MORNING AT A FEW SITES AND POSSIBLY
AGAIN TONIGHT AT OTHER SITES. HERE ARE THE RECORDS FOR TONIGHT.
RECORD LOWS FOR FEBRUARY 28...
MOLINE.........-9 IN 1962
CEDAR RAPIDS...-17 IN 1962
DUBUQUE........-10 IN 1962
BURLINGTON.....-7 IN 1962
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...WIND CHILL ADVISORY UNTIL 9 AM CST THIS MORNING FOR BENTON-
BUCHANAN-CEDAR-CLINTON-DELAWARE-DES MOINES-DUBUQUE-HENRY IA-
IOWA-JACKSON-JEFFERSON-JOHNSON-JONES-KEOKUK-LEE-LINN-LOUISA-
MUSCATINE-SCOTT-VAN BUREN-WASHINGTON.
IL...WIND CHILL ADVISORY UNTIL 9 AM CST THIS MORNING FOR BUREAU-
CARROLL-HANCOCK-HENDERSON-HENRY IL-JO DAVIESS-MCDONOUGH-
MERCER-PUTNAM-ROCK ISLAND-STEPHENSON-WARREN-WHITESIDE.
MO...WIND CHILL ADVISORY UNTIL 9 AM CST THIS MORNING FOR CLARK-
SCOTLAND.
&&
$$
UPDATE...GIBBS
SYNOPSIS...GIBBS
SHORT TERM...GIBBS
LONG TERM...ERVIN
AVIATION...GIBBS
CLIMATE...GIBBS
AREA FORECAST DISCUSSION...UPDATED
NWS QUAD CITIES IA IL
547 AM CST FRI FEB 27 2015
.SYNOPSIS...
ISSUED AT 307 AM CST FRI FEB 27 2015
HIGH PRESSURE WAS MOVING INTO THE CENTRAL PLAINS EARLY THIS
MORNING. WITH FRESH SNOWFALL AND CLEAR SKIES TEMPERATURES HAVE
PLUMMETED THIS MORNING TO QUITE POSSIBLY ONE OF THE COLDEST NIGHTS
OF THE YEAR. WINDS HAVE STAYED UP...WHICH HAS LEAD TO WIDESPREAD
WIND CHILLS BETWEEN 20 AND 30 BELOW ZERO WITH A FEW POCKETS OF 30
BELOW OR LOWER WIND CHILLS. WINDS ARE STARTING TO WANE AND
TEMPERATURES SHOULD DROP MORE.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 307 AM CST FRI FEB 27 2015
MAIN FORECAST CONCERN FOR THE SHORT TERM ARE TEMPERATURES TODAY
AND TONIGHT ACROSS THE AREA. WITH HIGH PRESSURE IN PLACE AND FRESH
SNOW COVER...GUIDANCE IS OF LITTLE HELP FOR TEMPERATURE FORECASTS.
AS FAR AS THE SYNOPTIC PATTERN IS CONCERNED...H5 RIDGING IS
BUILDING INTO THE CENTRAL UNITED STATES AS A SURFACE HIGH IS PROG
TO MOVE DIRECTLY OVER OUR CWA TODAY. WINDS SHOULD WANE...HOWEVER
COLD AIR AND FRESH SNOWFALL WILL LEAD TO COLD TEMPERATURES TODAY
AND TONIGHT. MODELS ARE OF LITTLE HELP...THIS MORNING FOR LOWS I
LOADED THE OBS AND THEN MADE TWEAKS FROM THERE AS THE RUC WAS THE
ONLY MODEL COLD ENOUGH WITH TEMPS. FOR TODAY AND TONIGHT...WENT
WITH THE ALLBLEND AND THEN TWEAKED TEMPERATURES FROM THERE. WIND
CHILLS TONIGHT SUGGEST THE NEED FOR ANOTHER WIND CHILL ADVISORY
FOR AREAS NORTH OF I80. WILL DEFER TO THE DAY TO SHIFT TO DECIDE
TO ISSUE THIS AS THERE IS ALREADY ONE OUT.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 307 AM CST FRI FEB 27 2015
TWO STORM SYSTEMS WILL IMPACT THE EXTENDED FORECAST...AND BOTH
CONTAIN POTENTIAL WINTER IMPACTS. AT THIS TIME...BOTH SYSTEMS ARE
RELATIVELY POOR IN CONFIDENCE OF EXACT DETAILS CONCERNING THESE
IMPACTS.
TO BEGIN THE EXTENDED...HIGH PRESSURE WILL BE MOVING OFF TO THE EAST
SATURDAY...AND WITH A VERY COLD START TO THE DAY...THE WEAK WAA WILL
LIKELY ONLY RESULT IN HIGHS IN THE MID TEENS NORTH TO MID 20S
SOUTH...DESPITE A HEALTHY AMOUNT OF LATE FEBRUARY SUNSHINE IN THE
MORNING. WARM ADVECTION BY AFTERNOON...WILL BRING MID LEVEL MOISTURE
NORTHWARD...WITH SOME MODELS CONTINUING TO BRUSH OUR SOUTHWEST WITH
DEEPER SATURATION BY LATE AFTERNOON. THE MODEL BLEND SHOWS FAR MORE
SIGNIFICANT MOISTURE ADVECTION BY SATURDAY NIGHT...AND I WILL
CONTINUE TO HIGHLIGHT THAT PERIOD THROUGH SUNDAY WITH HIGH POPS.
THIS EVENT IS GOING TO BE ALL SNOW...AND SHOULD HAVE RATIOS IN THE
12 TO 15 TO 1 RANGE...THUS AMOUNTS FROM SATURDAY EVENING THROUGH
SUNDAY AFTERNOON SHOULD RANGE FROM AROUND 1 INCH NORTHWEST...TO 2 TO
3 INCHES FROM IOWA CITY THROUGH THE QUAD CITIES TO STERLING...TO 3
TO 5 INCHES OVER FAR SOUTHEAST IOWA NORTHEAST MISSOURI TO NEAR
PRINCETON ILLINOIS. WHILE THOSE AMOUNTS ARE SUPPORTED BY THE MOST
LIKELY BLEND OF GUIDANCE THAT IS INDICATED AT THIS TIME...I AM NOT
CONFIDENT IN THEM YET. THE EVENT IS LIKELY GOING TO FALL INTO THE
ADVISORY RANGE...ESPECIALLY DUE TO THE LONGER THAN NORMAL DURATION
FOR THESE RANGE OF AMOUNTS. LOOKING AT UNCERTAINTY...THE CANADIAN
MODEL IS FARTHER SOUTH THAN THE ECMWF AND GFS...AND KEEPS THE
NORTHERN 3/4S OF THE CWA DRY...THUS ANOTHER REASON FOR HOLDING OFF
ON ANY EARLY HEADLINE AT THIS TIME. THE 06Z NAM...THROUGH 12Z
SUNDAY...ALSO KEEPS THE BULK OF MOISTURE AND FORCING SOUTH.
MONDAY WILL BE A BREAK BETWEEN LOW CONFIDENCE SYSTEM...AS THE DEEP
WESTERN TROF BECOMES EVEN MORE AMPLIFIED. THE MODELS HAVE SHOWN VERY
LITTLE CONSISTENCY OVER THE PAST FEW DAYS AND THROUGH TONIGHT WITH
RESPECT TO THE LOW TRACK...UPPER ENERGY TRACK...AND BAROCLINICITY OF
THIS POTENTIAL SYSTEM. ONE FEATURE THAT HAS BEEN SHOWN
CONSISTENTLY...HAS BEEN MOISTURE...WITH A SYNOPTIC SIGNAL OF AN OPEN
GULF OF MEXICO...AND EVEN OPEN CARIBBEAN. THE HIGH AMOUNTS OF
AVAILABLE MOISTURE ARE REASONS SUPPORTING LIKELY POPS MONDAY NIGHT
AND TUESDAY. WHILE NOT CONFIDENT IN THERMAL TRANSITION TIMING...IT
IS A BEST MODEL BLEND...AND CONCEPTUAL MODEL FIT FOR PCPN TO BEGIN
AS A WINTRY MIX OF SNOW/SLEET/FREEZING RAIN MONDAY
NIGHT...TRANSITIONING TO RAIN TUESDAY...THEN BACK TO SNOW AGAIN
TUESDAY NIGHT. THIS WET MESS COULD BE HIGH IMPACT...OR COULD BE
LARGELY BENIGN. IT IS VERY DIFFICULT TO TELL...AND WILL KEEP A
HEALTHY DOSE OF UNCERTAINTY IN OUR PRODUCTS.
FOLLOWING THIS SYSTEM...COLDER DRY WEATHER SETTLES BACK IN THE A FEW
DAYS BEFORE MODERATION LOOKS TO OCCUR IN ZONAL FLOW.
ERVIN
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 544 AM CST FRI FEB 27 2015
VFR CONDITIONS THROUGH THE PERIOD WITH LIGHT WINDS AS HIGH
PRESSURE SETTLES OVER THE AREA. WINDS SHOULD FAVOR W TO NW TODAY
AND THEN FAVOR S TO SE OVERNIGHT. OVERALL WINDS WILL BE VERY
LIGHT. ONLY CONCERN WOULD BE FRIGID TEMPERATURES TODAY AND
TONIGHT.
&&
.CLIMATE...
ISSUED AT 307 AM CST FRI FEB 27 2015
COULD SEE RECORD LOWS THIS MORNING AT A FEW SITES AND POSSIBLY
AGAIN TONIGHT AT OTHER SITES. HERE ARE THE RECORDS FOR TONIGHT.
RECORD LOWS FOR FEBRUARY 28...
MOLINE.........-9 IN 1962
CEDAR RAPIDS...-17 IN 1962
DUBUQUE........-10 IN 1962
BURLINGTON.....-7 IN 1962
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...WIND CHILL ADVISORY UNTIL 9 AM CST THIS MORNING FOR BENTON-
BUCHANAN-CEDAR-CLINTON-DELAWARE-DES MOINES-DUBUQUE-HENRY IA-
IOWA-JACKSON-JEFFERSON-JOHNSON-JONES-KEOKUK-LEE-LINN-LOUISA-
MUSCATINE-SCOTT-VAN BUREN-WASHINGTON.
IL...WIND CHILL ADVISORY UNTIL 9 AM CST THIS MORNING FOR BUREAU-
CARROLL-HANCOCK-HENDERSON-HENRY IL-JO DAVIESS-MCDONOUGH-
MERCER-PUTNAM-ROCK ISLAND-STEPHENSON-WARREN-WHITESIDE.
MO...WIND CHILL ADVISORY UNTIL 9 AM CST THIS MORNING FOR CLARK-
SCOTLAND.
&&
$$
SYNOPSIS...GIBBS
SHORT TERM...GIBBS
LONG TERM...ERVIN
AVIATION...GIBBS
CLIMATE...GIBBS
AREA FORECAST DISCUSSION
NWS GOODLAND KS
842 AM MST FRI FEB 27 2015
.UPDATE...
ISSUED AT 842 AM MST FRI FEB 27 2015
UPDATED THE FORECASTS TO REMOVE THE WIND CHILL ADVISORY ACROSS KIT
CARSON AND CHEYENNE COUNTIES AS WIND CHILL READINGS WILL GRADUALLY
RISE THE REST OF TODAY. OTHERWISE...LIGHT SNOW CONTINUES OVER THE
AREA. 12Z NAM SHOWS SNOW WILL DECREASE FROM NORTH TO SOUTH AFTER
18Z...THEN NEXT SHORT WAVE TROUGH WILL MOVE ACROSS SOUTHWEST
KANSAS TONIGHT BRINGING ANOTHER GOOD CHANCE OF SNOW...ESPECIALLY
SOUTH OF INTERSTATE 70.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY NIGHT)
ISSUED AT 323 AM MST FRI FEB 27 2015
EARLY MORNING WV IMAGERY AND RAP H5 ANALYSIS SHOW SHORTWAVE TROUGH
MOVING INTO NEBRASKA. MOISTURE PLUME EXTENDS ACROSS WESTERN KANSAS
AND EASTERN COLORADO. AT THE SURFACE 1038 MB HIGH PRESSURE IS
CENTERED OVER THE MISSOURI RIVER VALLEY NEAR THE NEBRASKA AND IOWA
STATE LINE. SOUTHEASTERLY FLOW IS IN PLACE ACROSS THE CWA WITH A
TIGHT TD GRADIENT FROM THE WEST (AROUND 10F) TO THE NORTHEAST (-2F).
REGARDING WIND CHILL ADVISORY THIS MORNING AND THE POSSIBILITY
TONIGHT...WINDS ARE STILL EXPECTED TO INCREASE IN THE 12-15Z TIME
PERIOD THIS MORNING. BASED ON CURRENT WIND FORECAST...IF TEMPS IN
THE ADVISED AREA WERE TO DROP TO AROUND 4F OR LOWER WINDS WOULD
SUPPORT -15F WIND CHILLS. SHORT RANGE GUIDANCE GENERALLY KEEPS
TEMPS STEADY IN THE WEST WHERE THE HIGHER WINDS WILL BE AND WIND
CHILLS IN THE -10F OR WARMER RANGE. AT THIS POINT I SEE NO REASON
TO CHANGE ADVISORY CONSIDERING HOW CLOSE IT WILL BE. CONDITIONS
TONIGHT/EARLY SATURDAY MORNING COULD BE SIMILAR AS THIS
MORNING...WITH CLOUD COVER THE LIMITING FACTOR ON IDEAL RADIATIONAL
CONDITIONS. IT COULD BE CLOSE TO ADVISORY CRITERIA...BUT WITH THE
AMOUNT OF UNCERTAINTY AND ONGOING ADVISORY THIS MORNING I PREFER
TO LET THE CURRENT ONE PLAY OUT.
TODAY...LIGHT SNOW HAS BEEN REPORTED ACROSS EASTERN COLORADO AND
PARTS OF NW KANSAS EARLY THIS MORNING...WITH LIGHT ACCUMULATIONS
APPARENT ON WEB CAMS AND OBSERVED AT WFO. SHORT RANGE GUIDANCE
SHOWS THIS ACTIVITY CONTINUING TO TRANSITION SOUTHEAST ACROSS THE
REGION AS SHORTWAVE SLIDES EAST. CONSIDERING THE LIGHT NATURE OF
THE RADAR RETURNS ACROSS THE CWA IT IS HARD TO JUDGE HOW MUCH
ACCUMULATION IS ACTUALLY OCCURRING AND TREND IN GUIDANCE HAS BE
TOWARDS LOWER VALUES. MAIN THREAT FOR MEANINGFUL ACCUMULATIONS
WILL BE BEFORE 18Z...WITH CHANCE FOR MEASURABLE SNOW DIMINISHING
AFTERWARDS. IT APPEARS 1-2" SHOULD STILL BE THE HIGH END OF
ACCUMULATION FROM NOW THROUGH MIDDAY (MAINLY ALONG AND SOUTH OF
I-70). AS WINDS INCREASE WE COULD STILL SEE BLOWING SNOW
DEVELOP...HOWEVER THIS SHOULD BE AN ISOLATED THREAT AND TIED TO
ANY NEW SNOWFALL RATHER THAN OLD/CRUSTED OVER SNOW PACK. I KEPT
PATCHY BLOWING SNOW MENTION AND DO NOT THINK THERE IS A NEED FOR
ADVISORY AS VIS RESTRICTIONS FROM BLOWING SNOW WILL BE ISOLATED.
TONIGHT-SUNDAY NIGHT...H3 JET BEGINS TO TRANSITION NORTHWARD OVER
THE CWA AS TROUGH DEEPENS ACROSS THE SW US. RESULT WITH BE BROAD
AREA OF WEAK FORCING DEVELOPING ACROSS THE CWA...WITH BETTER FORCING
TIED TO MID LEVEL CIRCULATIONS ROTATING THROUGH THE MEAN FLOW.
GUIDANCE HAS TRENDED TOWARDS BETTER PRECIP SIGNALS EITHER WELL WEST
OF THE CWA...OR SOUTHEAST OF THE CWA. WE COULD STILL SEE LIGHT
ACCUMULATIONS...HOWEVER BEST CHANCE SEEMS TO BE IN OUR
EASTERN/SOUTHEAST CWA AND AMOUNTS HAVE TRENDED LOWER WITH 1-2" ON
THE HIGHER END OF TOTAL ACCUMULATIONS SATURDAY/SATURDAY NIGHT.
CONSIDERING THE TRENDS AND AMOUNT OF UNCERTAINTY I TRENDED POPS
LOWER THROUGH ALL THESE PERIODS AND ADJUSTED HIGHEST POPS TO BE IN
THE EASTERN CWA SATURDAY AFTERNOON/EVENING CORRELATING WITH BEST
PRECIP SIGNAL.
REGARDING TEMPS...AS HAS BEEN THE CASE WE SHOULD SEE BELOW NORMAL
TEMPERATURES CONTINUE WITH ONLY SLOW MODERATION TO TEMPS ALOFT
SATURDAY/SUNDAY AS SW FLOW ALOFT DEVELOPS ACROSS THE SOUTHERN PLANS
OVER THE TOP OF THE PERSISTENT ARCTIC AIR MASS. CLOUD COVER AND THE
POSSIBILITY OF PRECIP CONTINUES TO COMPLICATE DAYTIME/NIGHTTIME
TEMPS...SO ONLY MADE MINOR ADJUSTMENTS TO REFLECT CURRENT
CONSENSUS/MODEL TRENDS. LITTLE CHANGE FROM PREVIOUS FORECAST.
.LONG TERM...(MONDAY THROUGH THURSDAY NIGHT)
ISSUED AT 323 AM MST FRI FEB 27 2015
MODELS HAVE THE JET POSITIONED SLIGHTLY FURTHER NORTH DURING THE
FIRST PART OF NEXT WEEK WHICH MAY END UP KEEPING TEMPERATURES
SLIGHTLY WARMER AND WILL LIKELY ALSO MOVE THE JET ENHANCED AREA OF
PRECIPITATION FURTHER NORTH ACROSS THE FORECAST AREA. MODELS ARE
ENDING PRECIPITATION ACROSS THE FORECAST AREA WEDNESDAY MORNING AND
HAVE DRY CONDITIONS AFTER THAT.
THE UPPER LOW CENTER THAT STARTS OUT AS A CLOSED LOW OVER OVER
SOUTHERN CALIFORNIA ON SUNDAY EJECTS OUT ACROSS THE SOUTHERN ROCKIES
AND CENTRAL HIGH PLAINS REGION AS AN OPEN WAVE ON MONDAY NIGHT/EARLY
TUESDAY. THIS IS AHEAD OF A SHORT WAVE TROUGH DROPPING INTO THE
BASE OF THE MAIN TROUGH AXIS OVER BAJA AND ANOTHER LOW IN PHASE WITH
THE MAIN UPPER TROUGH THAT BEGINS MOVING FROM SOUTH CENTRAL CANADA
INTO THE NORTHERN PLAINS. THE ENTIRE MAJOR TROUGH AXIS SWEEPS EAST
OF THE ROCKIES AND ACROSS THE PLAINS WEDNESDAY EVENING WITH
NORTHWEST FLOW AND RIDGING TO EXTEND ACROSS THE ROCKIES INTO THE
HIGH PLAINS REGION BY THURSDAY AND THURSDAY NIGHT.
A SURFACE LOW AND COLD FRONT ASSOCIATED WITH THE UPPER SHORT WAVE
TROUGH LIFTING ACROSS THE REGION ON TUESDAY USHERS IN COOLER
TEMPERATURES ACROSS FORECAST AREA AND SPREADS THE PRECIPITATION
SOUTHWARD ACROSS THE FORECAST AREA TUESDAY NIGHT AND WEDNESDAY
MORNING. SNOW WILL COME TO AN END ON WEDNESDAY WITH MUCH COLDER
TEMPERATURES AS SURFACE HIGH PRESSURE MOVES INTO THE REGION. THE
COLD AIR SHOULD NOT LAST LONG AS RETURN FLOW AROUND THE EXITING HIGH
PRESSURE AREA TURNS SOUTHWESTERLY ACROSS THE FORECAST AREA AND THE
RIDGE ALOFT BUILDS IN.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 428 AM MST FRI FEB 27 2015
LIGHT SNOW IS CONTINUING TO IMPACT THE KGLD TERMINAL WITH IFR VIS
AND MVFR CIGS. VFR CONDITIONS SHOULD CONTINUE THROUGH THE DAYTIME
PERIOD AT KMCK. CONDITIONS COULD VARY THIS MORNING AT KGLD THOUGH
IMPROVEMENT ABOVE IFR ISNT LIKELY UNTIL LATER THIS MORNING AS LONG
AS LIGHT SNOW LINGERS. AS WINDS INCREASE DURING THE DAY BLOWING
SNOW MAY BE POSSIBLE...HOWEVER CONFIDENCE IN REDUCED VIS DUE TO
THIS IS TOO LOW TO ADD MENTION DURING THIS UPDATE. MVFR CIGS
SHOULD CONTINUE THIS AFTERNOON/EVENING AT KGLD BASED ON TRENDS IN
GUIDANCE...THOUGH THERE COULD BE BREAKS IN STRATUS ALLOWING FOR
BRIEF PERIODS OF VFR CONDITIONS. LOW LEVEL MOISTURE RETURN WILL
RESULT IN IFR CIGS DEVELOPING LATE TONIGHT AND MVFR DEVELOPING AT
KMCK LATE TONIGHT. WINDS SHOULD LIMIT LOW LEVEL
SATURATION...HOWEVER ADVECTION FOG CANNOT BE COMPLETELY RULE OUT.
LIGHT SNOW MAY ALSO REDEVELOP...THOUGH BETTER CHANCE APPEAR TO
REMAIN SOUTH AND EAST OF BOTH KGLD AND KMCK.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...MENTZER
SHORT TERM...DR
LONG TERM...99
AVIATION...DR
AREA FORECAST DISCUSSION
NWS GOODLAND KS
428 AM MST FRI FEB 27 2015
.SHORT TERM...(TODAY THROUGH SUNDAY NIGHT)
ISSUED AT 323 AM MST FRI FEB 27 2015
EARLY MORNING WV IMAGERY AND RAP H5 ANALYSIS SHOW SHORTWAVE TROUGH
MOVING INTO NEBRASKA. MOISTURE PLUME EXTENDS ACROSS WESTERN KANSAS
AND EASTERN COLORADO. AT THE SURFACE 1038 MB HIGH PRESSURE IS
CENTERED OVER THE MISSOURI RIVER VALLEY NEAR THE NEBRASKA AND IOWA
STATE LINE. SOUTHEASTERLY FLOW IS IN PLACE ACROSS THE CWA WITH A
TIGHT TD GRADIENT FROM THE WEST (AROUND 10F) TO THE NORTHEAST (-2F).
REGARDING WIND CHILL ADVISORY THIS MORNING AND THE POSSIBILITY
TONIGHT...WINDS ARE STILL EXPECTED TO INCREASE IN THE 12-15Z TIME
PERIOD THIS MORNING. BASED ON CURRENT WIND FORECAST...IF TEMPS IN
THE ADVISED AREA WERE TO DROP TO AROUND 4F OR LOWER WINDS WOULD
SUPPORT -15F WIND CHILLS. SHORT RANGE GUIDANCE GENERALLY KEEPS
TEMPS STEADY IN THE WEST WHERE THE HIGHER WINDS WILL BE AND WIND
CHILLS IN THE -10F OR WARMER RANGE. AT THIS POINT I SEE NO REASON
TO CHANGE ADVISORY CONSIDERING HOW CLOSE IT WILL BE. CONDITIONS
TONIGHT/EARLY SATURDAY MORNING COULD BE SIMILAR AS THIS
MORNING...WITH CLOUD COVER THE LIMITING FACTOR ON IDEAL RADIATIONAL
CONDITIONS. IT COULD BE CLOSE TO ADVISORY CRITERIA...BUT WITH THE
AMOUNT OF UNCERTAINTY AND ONGOING ADVISORY THIS MORNING I PREFER
TO LET THE CURRENT ONE PLAY OUT.
TODAY...LIGHT SNOW HAS BEEN REPORTED ACROSS EASTERN COLORADO AND
PARTS OF NW KANSAS EARLY THIS MORNING...WITH LIGHT ACCUMULATIONS
APPARENT ON WEB CAMS AND OBSERVED AT WFO. SHORT RANGE GUIDANCE
SHOWS THIS ACTIVITY CONTINUING TO TRANSITION SOUTHEAST ACROSS THE
REGION AS SHORTWAVE SLIDES EAST. CONSIDERING THE LIGHT NATURE OF
THE RADAR RETURNS ACROSS THE CWA IT IS HARD TO JUDGE HOW MUCH
ACCUMULATION IS ACTUALLY OCCURRING AND TREND IN GUIDANCE HAS BE
TOWARDS LOWER VALUES. MAIN THREAT FOR MEANINGFUL ACCUMULATIONS
WILL BE BEFORE 18Z...WITH CHANCE FOR MEASURABLE SNOW DIMINISHING
AFTERWARDS. IT APPEARS 1-2" SHOULD STILL BE THE HIGH END OF
ACCUMULATION FROM NOW THROUGH MIDDAY (MAINLY ALONG AND SOUTH OF
I-70). AS WINDS INCREASE WE COULD STILL SEE BLOWING SNOW
DEVELOP...HOWEVER THIS SHOULD BE AN ISOLATED THREAT AND TIED TO
ANY NEW SNOWFALL RATHER THAN OLD/CRUSTED OVER SNOW PACK. I KEPT
PATCHY BLOWING SNOW MENTION AND DO NOT THINK THERE IS A NEED FOR
ADVISORY AS VIS RESTRICTIONS FROM BLOWING SNOW WILL BE ISOLATED.
TONIGHT-SUNDAY NIGHT...H3 JET BEGINS TO TRANSITION NORTHWARD OVER
THE CWA AS TROUGH DEEPENS ACROSS THE SW US. RESULT WITH BE BROAD
AREA OF WEAK FORCING DEVELOPING ACROSS THE CWA...WITH BETTER FORCING
TIED TO MID LEVEL CIRCULATIONS ROTATING THROUGH THE MEAN FLOW.
GUIDANCE HAS TRENDED TOWARDS BETTER PRECIP SIGNALS EITHER WELL WEST
OF THE CWA...OR SOUTHEAST OF THE CWA. WE COULD STILL SEE LIGHT
ACCUMULATIONS...HOWEVER BEST CHANCE SEEMS TO BE IN OUR
EASTERN/SOUTHEAST CWA AND AMOUNTS HAVE TRENDED LOWER WITH 1-2" ON
THE HIGHER END OF TOTAL ACCUMULATIONS SATURDAY/SATURDAY NIGHT.
CONSIDERING THE TRENDS AND AMOUNT OF UNCERTAINTY I TRENDED POPS
LOWER THROUGH ALL THESE PERIODS AND ADJUSTED HIGHEST POPS TO BE IN
THE EASTERN CWA SATURDAY AFTERNOON/EVENING CORRELATING WITH BEST
PRECIP SIGNAL.
REGARDING TEMPS...AS HAS BEEN THE CASE WE SHOULD SEE BELOW NORMAL
TEMPERATURES CONTINUE WITH ONLY SLOW MODERATION TO TEMPS ALOFT
SATURDAY/SUNDAY AS SW FLOW ALOFT DEVELOPS ACROSS THE SOUTHERN PLANS
OVER THE TOP OF THE PERSISTENT ARCTIC AIR MASS. CLOUD COVER AND THE
POSSIBILITY OF PRECIP CONTINUES TO COMPLICATE DAYTIME/NIGHTTIME
TEMPS...SO ONLY MADE MINOR ADJUSTMENTS TO REFLECT CURRENT
CONSENSUS/MODEL TRENDS. LITTLE CHANGE FROM PREVIOUS FORECAST.
.LONG TERM...(MONDAY THROUGH THURSDAY NIGHT)
ISSUED AT 323 AM MST FRI FEB 27 2015
MODELS HAVE THE JET POSITIONED SLIGHTLY FURTHER NORTH DURING THE
FIRST PART OF NEXT WEEK WHICH MAY END UP KEEPING TEMPERATURES
SLIGHTLY WARMER AND WILL LIKELY ALSO MOVE THE JET ENHANCED AREA OF
PRECIPITATION FURTHER NORTH ACROSS THE FORECAST AREA. MODELS ARE
ENDING PRECIPITATION ACROSS THE FORECAST AREA WEDNESDAY MORNING AND
HAVE DRY CONDITIONS AFTER THAT.
THE UPPER LOW CENTER THAT STARTS OUT AS A CLOSED LOW OVER OVER
SOUTHERN CALIFORNIA ON SUNDAY EJECTS OUT ACROSS THE SOUTHERN ROCKIES
AND CENTRAL HIGH PLAINS REGION AS AN OPEN WAVE ON MONDAY NIGHT/EARLY
TUESDAY. THIS IS AHEAD OF A SHORT WAVE TROUGH DROPPING INTO THE
BASE OF THE MAIN TROUGH AXIS OVER BAJA AND ANOTHER LOW IN PHASE WITH
THE MAIN UPPER TROUGH THAT BEGINS MOVING FROM SOUTH CENTRAL CANADA
INTO THE NORTHERN PLAINS. THE ENTIRE MAJOR TROUGH AXIS SWEEPS EAST
OF THE ROCKIES AND ACROSS THE PLAINS WEDNESDAY EVENING WITH
NORTHWEST FLOW AND RIDGING TO EXTEND ACROSS THE ROCKIES INTO THE
HIGH PLAINS REGION BY THURSDAY AND THURSDAY NIGHT.
A SURFACE LOW AND COLD FRONT ASSOCIATED WITH THE UPPER SHORT WAVE
TROUGH LIFTING ACROSS THE REGION ON TUESDAY USHERS IN COOLER
TEMPERATURES ACROSS FORECAST AREA AND SPREADS THE PRECIPITATION
SOUTHWARD ACROSS THE FORECAST AREA TUESDAY NIGHT AND WEDNESDAY
MORNING. SNOW WILL COME TO AN END ON WEDNESDAY WITH MUCH COLDER
TEMPERATURES AS SURFACE HIGH PRESSURE MOVES INTO THE REGION. THE
COLD AIR SHOULD NOT LAST LONG AS RETURN FLOW AROUND THE EXITING HIGH
PRESSURE AREA TURNS SOUTHWESTERLY ACROSS THE FORECAST AREA AND THE
RIDGE ALOFT BUILDS IN.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 428 AM MST FRI FEB 27 2015
LIGHT SNOW IS CONTINUING TO IMPACT THE KGLD TERMINAL WITH IFR VIS
AND MVFR CIGS. VFR CONDITIONS SHOULD CONTINUE THROUGH THE DAYTIME
PERIOD AT KMCK. CONDITIONS COULD VARY THIS MORNING AT KGLD THOUGH
IMPROVEMENT ABOVE IFR ISNT LIKELY UNTIL LATER THIS MORNING AS LONG
AS LIGHT SNOW LINGERS. AS WINDS INCREASE DURING THE DAY BLOWING
SNOW MAY BE POSSIBLE...HOWEVER CONFIDENCE IN REDUCED VIS DUE TO
THIS IS TOO LOW TO ADD MENTION DURING THIS UPDATE. MVFR CIGS
SHOULD CONTINUE THIS AFTERNOON/EVENING AT KGLD BASED ON TRENDS IN
GUIDANCE...THOUGH THERE COULD BE BREAKS IN STRATUS ALLOWING FOR
BRIEF PERIODS OF VFR CONDITIONS. LOW LEVEL MOISTURE RETURN WILL
RESULT IN IFR CIGS DEVELOPING LATE TONIGHT AND MVFR DEVELOPING AT
KMCK LATE TONIGHT. WINDS SHOULD LIMIT LOW LEVEL
SATURATION...HOWEVER ADVECTION FOG CANNOT BE COMPLETELY RULE OUT.
LIGHT SNOW MAY ALSO REDEVELOP...THOUGH BETTER CHANCE APPEAR TO
REMAIN SOUTH AND EAST OF BOTH KGLD AND KMCK.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...WIND CHILL ADVISORY UNTIL 11 AM MST THIS MORNING FOR COZ091-092.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...99
AVIATION...DR
AREA FORECAST DISCUSSION
NWS GOODLAND KS
323 AM MST FRI FEB 27 2015
.SHORT TERM...(TODAY THROUGH SUNDAY NIGHT)
ISSUED AT 323 AM MST FRI FEB 27 2015
EARLY MORNING WV IMAGERY AND RAP H5 ANALYSIS SHOW SHORTWAVE TROUGH
MOVING INTO NEBRASKA. MOISTURE PLUME EXTENDS ACROSS WESTERN KANSAS
AND EASTERN COLORADO. AT THE SURFACE 1038 MB HIGH PRESSURE IS
CENTERED OVER THE MISSOURI RIVER VALLEY NEAR THE NEBRASKA AND IOWA
STATE LINE. SOUTHEASTERLY FLOW IS IN PLACE ACROSS THE CWA WITH A
TIGHT TD GRADIENT FROM THE WEST (AROUND 10F) TO THE NORTHEAST (-2F).
REGARDING WIND CHILL ADVISORY THIS MORNING AND THE POSSIBILITY
TONIGHT...WINDS ARE STILL EXPECTED TO INCREASE IN THE 12-15Z TIME
PERIOD THIS MORNING. BASED ON CURRENT WIND FORECAST...IF TEMPS IN
THE ADVISED AREA WERE TO DROP TO AROUND 4F OR LOWER WINDS WOULD
SUPPORT -15F WIND CHILLS. SHORT RANGE GUIDANCE GENERALLY KEEPS
TEMPS STEADY IN THE WEST WHERE THE HIGHER WINDS WILL BE AND WIND
CHILLS IN THE -10F OR WARMER RANGE. AT THIS POINT I SEE NO REASON
TO CHANGE ADVISORY CONSIDERING HOW CLOSE IT WILL BE. CONDITIONS
TONIGHT/EARLY SATURDAY MORNING COULD BE SIMILAR AS THIS
MORNING...WITH CLOUD COVER THE LIMITING FACTOR ON IDEAL RADIATIONAL
CONDITIONS. IT COULD BE CLOSE TO ADVISORY CRITERIA...BUT WITH THE
AMOUNT OF UNCERTAINTY AND ONGOING ADVISORY THIS MORNING I PREFER
TO LET THE CURRENT ONE PLAY OUT.
TODAY...LIGHT SNOW HAS BEEN REPORTED ACROSS EASTERN COLORADO AND
PARTS OF NW KANSAS EARLY THIS MORNING...WITH LIGHT ACCUMULATIONS
APPARENT ON WEB CAMS AND OBSERVED AT WFO. SHORT RANGE GUIDANCE
SHOWS THIS ACTIVITY CONTINUING TO TRANSITION SOUTHEAST ACROSS THE
REGION AS SHORTWAVE SLIDES EAST. CONSIDERING THE LIGHT NATURE OF
THE RADAR RETURNS ACROSS THE CWA IT IS HARD TO JUDGE HOW MUCH
ACCUMULATION IS ACTUALLY OCCURRING AND TREND IN GUIDANCE HAS BE
TOWARDS LOWER VALUES. MAIN THREAT FOR MEANINGFUL ACCUMULATIONS
WILL BE BEFORE 18Z...WITH CHANCE FOR MEASURABLE SNOW DIMINISHING
AFTERWARDS. IT APPEARS 1-2" SHOULD STILL BE THE HIGH END OF
ACCUMULATION FROM NOW THROUGH MIDDAY (MAINLY ALONG AND SOUTH OF
I-70). AS WINDS INCREASE WE COULD STILL SEE BLOWING SNOW
DEVELOP...HOWEVER THIS SHOULD BE AN ISOLATED THREAT AND TIED TO
ANY NEW SNOWFALL RATHER THAN OLD/CRUSTED OVER SNOW PACK. I KEPT
PATCHY BLOWING SNOW MENTION AND DO NOT THINK THERE IS A NEED FOR
ADVISORY AS VIS RESTRICTIONS FROM BLOWING SNOW WILL BE ISOLATED.
TONIGHT-SUNDAY NIGHT...H3 JET BEGINS TO TRANSITION NORTHWARD OVER
THE CWA AS TROUGH DEEPENS ACROSS THE SW US. RESULT WITH BE BROAD
AREA OF WEAK FORCING DEVELOPING ACROSS THE CWA...WITH BETTER FORCING
TIED TO MID LEVEL CIRCULATIONS ROTATING THROUGH THE MEAN FLOW.
GUIDANCE HAS TRENDED TOWARDS BETTER PRECIP SIGNALS EITHER WELL WEST
OF THE CWA...OR SOUTHEAST OF THE CWA. WE COULD STILL SEE LIGHT
ACCUMULATIONS...HOWEVER BEST CHANCE SEEMS TO BE IN OUR
EASTERN/SOUTHEAST CWA AND AMOUNTS HAVE TRENDED LOWER WITH 1-2" ON
THE HIGHER END OF TOTAL ACCUMULATIONS SATURDAY/SATURDAY NIGHT.
CONSIDERING THE TRENDS AND AMOUNT OF UNCERTAINTY I TRENDED POPS
LOWER THROUGH ALL THESE PERIODS AND ADJUSTED HIGHEST POPS TO BE IN
THE EASTERN CWA SATURDAY AFTERNOON/EVENING CORRELATING WITH BEST
PRECIP SIGNAL.
REGARDING TEMPS...AS HAS BEEN THE CASE WE SHOULD SEE BELOW NORMAL
TEMPERATURES CONTINUE WITH ONLY SLOW MODERATION TO TEMPS ALOFT
SATURDAY/SUNDAY AS SW FLOW ALOFT DEVELOPS ACROSS THE SOUTHERN PLANS
OVER THE TOP OF THE PERSISTENT ARCTIC AIR MASS. CLOUD COVER AND THE
POSSIBILITY OF PRECIP CONTINUES TO COMPLICATE DAYTIME/NIGHTTIME
TEMPS...SO ONLY MADE MINOR ADJUSTMENTS TO REFLECT CURRENT
CONSENSUS/MODEL TRENDS. LITTLE CHANGE FROM PREVIOUS FORECAST.
.LONG TERM...(MONDAY THROUGH THURSDAY NIGHT)
ISSUED AT 323 AM MST FRI FEB 27 2015
MODELS HAVE THE JET POSITIONED SLIGHTLY FURTHER NORTH DURING THE
FIRST PART OF NEXT WEEK WHICH MAY END UP KEEPING TEMPERATURES
SLIGHTLY WARMER AND WILL LIKELY ALSO MOVE THE JET ENHANCED AREA OF
PRECIPITATION FURTHER NORTH ACROSS THE FORECAST AREA. MODELS ARE
ENDING PRECIPITATION ACROSS THE FORECAST AREA WEDNESDAY MORNING AND
HAVE DRY CONDITIONS AFTER THAT.
THE UPPER LOW CENTER THAT STARTS OUT AS A CLOSED LOW OVER OVER
SOUTHERN CALIFORNIA ON SUNDAY EJECTS OUT ACROSS THE SOUTHERN ROCKIES
AND CENTRAL HIGH PLAINS REGION AS AN OPEN WAVE ON MONDAY NIGHT/EARLY
TUESDAY. THIS IS AHEAD OF A SHORT WAVE TROUGH DROPPING INTO THE
BASE OF THE MAIN TROUGH AXIS OVER BAJA AND ANOTHER LOW IN PHASE WITH
THE MAIN UPPER TROUGH THAT BEGINS MOVING FROM SOUTH CENTRAL CANADA
INTO THE NORTHERN PLAINS. THE ENTIRE MAJOR TROUGH AXIS SWEEPS EAST
OF THE ROCKIES AND ACROSS THE PLAINS WEDNESDAY EVENING WITH
NORTHWEST FLOW AND RIDGING TO EXTEND ACROSS THE ROCKIES INTO THE
HIGH PLAINS REGION BY THURSDAY AND THURSDAY NIGHT.
A SURFACE LOW AND COLD FRONT ASSOCIATED WITH THE UPPER SHORT WAVE
TROUGH LIFTING ACROSS THE REGION ON TUESDAY USHERS IN COOLER
TEMPERATURES ACROSS FORECAST AREA AND SPREADS THE PRECIPITATION
SOUTHWARD ACROSS THE FORECAST AREA TUESDAY NIGHT AND WEDNESDAY
MORNING. SNOW WILL COME TO AN END ON WEDNESDAY WITH MUCH COLDER
TEMPERATURES AS SURFACE HIGH PRESSURE MOVES INTO THE REGION. THE
COLD AIR SHOULD NOT LAST LONG AS RETURN FLOW AROUND THE EXITING HIGH
PRESSURE AREA TURNS SOUTHWESTERLY ACROSS THE FORECAST AREA AND THE
RIDGE ALOFT BUILDS IN.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 958 PM MST THU FEB 26 2015
LATEST RADAR TRENDS INDICATE THAT VFR CONDITIONS SHOULD
DETERIORATE TO MVFR AT KGLD OVERNIGHT WITH LIGHT SNOW DEVELOPING.
MODELS INDICATE THE SNOW SHOULD TAPER OFF BY MIDDAY BUT MVFR WILL
PERSIST. VFR CONDITIONS WILL CONTINUE AT KMCK FOR MOST OF THE
NEXT 24 HOURS. HOWEVER, THE FORECAST SOUNDING FOR KMCK SHOWS SOME
STRATUS DEVELOPING AND PERSISTING INTO FRIDAY EVENING.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...WIND CHILL ADVISORY UNTIL 11 AM MST THIS MORNING FOR COZ091-092.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...99
AVIATION...FS
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
846 AM EST FRI FEB 27 2015
.UPDATE...
ANOTHER RECORD SETTING COLD MORNING AS ALL THREE CLIMATE SITES
BROKE OR TIED THEIR RESPECTIVE DAILY RECORDS.
FNT LOW WAS AT LEAST -17 F (UNABLE TO DIAL IN TO GET FINAL VALUE).
SAGINAW LOW WAS -9 AT 707 AM.
DETROIT TIED RECORD LOW...WITH -4 F AT 717 AM.
12Z DTX SOUNDING INDICATED A 925 MB TEMP OF -19 C...AND WITH THE
COLD START AND SOME LAKE CLOUDS EXPECTED TO PUSH EAST THIS
AFTERNOON (SEE RUC13 925 MB RH) UNDER LIGHT WESTERLY
FLOW...ESPECIALLY NORTHERN AREAS...MAXES WILL PROBABLY ONLY TOP
OUT IN THE MID TEENS...ON THE LOWER END OF THE GOING FORECAST.
&&
.AVIATION...ISSUED 550 AM EST FRI FEB 27 2015
SURFACE HIGH PRESSURE BUILDING EASTWARD INTO THE REGION WILL
CONTINUE TO SUPPORT A VERY DRY AIR MASS. WIND DIRECTIONS ARE
FORECASTED TO EMERGE SOUTHWESTERLY TODAY...BRINGING THE POTENTIAL
FOR LAKE MICHIGAN MOISTURE TO WORK UNDER THE INVERSION BASE AT 4-5
KFT AGL. MODEL SOUNDINGS ALSO SUPPORT A DIURNAL COMPONTENT TO
POTENTIAL CLOUD COVER. DOWNSTREAM TRAJECTORY CONTINUES TO SUPPORT
THE BEST POTENTIAL FOR THE NORTHERN TAF SITES.
//DTW THRESHOLD PROBABILITIES...
* LOW CONFIDENCE IN CEILING BELOW 5000 FT FRIDAY AFTERNOON.
&&
.PREV DISCUSSION...ISSUED 358 AM EST FRI FEB 27 2015
SHORT TERM...TODAY AND TONIGHT
RECORD LOWS FOR FEB 27
DETROIT AREA: -4 (1934)
FLINT AREA: -14 (1994)
SAGINAW: -8 (1934)
ANOTHER COLD MORNING ACROSS SOUTHEASTERN MICHIGAN WITH AN ARCTIC
SURFACE RIDGE LOCKED IN OVERHEAD. NIL WIND AND CLEAR SKIES HAS LED
TO FAVORABLE RADIATIVE COOLING CONDITIONS. SURFACE TEMPERATURES
CURRENTLY RANGE FROM 0 TO 10 DEGREES BELOW ZERO AS OF 3AM. WITH A
LACK OF LOW CLOUD DISCERNIBLE IN IR IMAGERY...EXPECTATIONS ARE FOR
SURFACE TEMPERATURES TO CONTINUE TO BOTTOM OUT BEFORE SUNRISE WITH
MANY RURAL LOCATIONS REACHING 10 TO 20 DEGREES BELOW ZERO. WITH A
DECOUPLED SURFACE LAYER...WILL HONOR THE DECISION OF PRIOR SHIFTS
AND NOT ISSUE A WIND CHILL ADVISORY.
COLDEST MIDLEVEL TEMPERATURES PUSHING OUT OF THE STATE TODAY IN
COMBINATION WITH AN SURFACE ANTICYCLONE PUSHING INTO PORTIONS OF
OHIO WILL ALLOW WIND DIRECTIONS OVER SOUTHEASTERN MICHIGAN TO MAKE A
CONCERTED MOVE TO SOUTHWESTERLY. ENHANCED MOISTURE AND LAKE MICHIGAN
CLOUD DEBRIS IS PROGGED TO STREAM EASTWARD WITH TIME...SHOWN TO
SLIDE THROUGH PORTIONS OF THE CWA BY THIS AFTERNOON AND INTO THE
EARLY EVENING. RAP SOUNDINGS SUGGEST THERE WILL BE A CONSIDERABLE
DIURNAL COMPONENT TO ANY SKY COVER. WIND TRAJECTORIES POINT TO THE
NORTHERN CWA/SAGAINAW VALLEY AS THE MORE FAVORABLE LOCATION FOR
CLOUDS. WITH SUN...SHADED A DEGREE OR TWO HIGHER THAN MOS GUIDANCE
FOR HIGHS.
SURFACE HIGH PRESSURE PUSHING THROUGH INDIANA AND OHIO WILL SET
ANOTHER NIGHT UP FOR CALM WINDS ACROSS THE SOUTHERN HALF OF THE CWA.
LOWERED MINS FOR AREAS SOUTH OF DETROIT. OTHERWISE...A PRESSURE
GRADIENT IN PLACE OVER THE TRI CITIES/NORTHERN THUMB AND SOME
POTENTIAL FOR LINGERING CLOUDS LIMITS THE TEMPERATURE FALL POTENTIAL
FOR TONIGHT.
LONG TERM...
COLD AIRMASS WILL REMAIN IN PLACE INTO EARLY THIS WEEKEND ALTHOUGH
TEMPERATURES WILL MODERATE EVER SO SLIGHTLY AS THE LATEST ARCTIC
HIGH PRESSURE SHIFTS TO THE EAST OF THE AREA SATURDAY NIGHT. HIGHS
ON SATURDAY WILL CLIMB TO AROUND 20F WITH LOWS THAT NIGHT HOLDING
INTO THE SINGLE DIGITS TO NEAR 10F AS BOTH THE COLDEST AIR SHIFTS
EAST AND EXPANDING CLOUD COVER WORKS INTO THE AREA WITH THE APPROACH
OF A LOW PRESSURE SYSTEM.
00Z MODEL RUNS...SAVE THE NAM12...BASICALLY SUPPORT THE PREVIOUS
FORECAST AS ROUGHLY 1 TO 2 INCHES OF SNOW FALL FROM THE I-69
CORRIDOR NORTH LATE SATURDAY NIGHT INTO EARLY SUNDAY EVENING WITH 2
TO 3 INCHES SOUTH OF THAT INTO METRO DETROIT AS H7 SPECIFIC HUMIDITY
CLIMBS TO AROUND 2 G/KG ALONG THE M-59 CORRIDOR. GIVEN THE
RELATIVELY HIGH SNOW TO LIQUID RATIOS EXPECTED WITH THE COLD AIRMASS
IN PLACE...15:1 OR A BIT MORE...WOULD NOT BE SURPRISED TO SEE UP TO
4 INCHES FROM THE I-94 CORRIDOR SOUTHWARD.
TEMPERATURES WILL EDGE BACK DOWN EARLY NEXT WEEK...BUT TO MUCH MORE
REASONABLE LEVELS THAN THE PAST SEVERAL WEEKS AS HIGHS MONDAY REACH
THE MID/UPPER 20S AND LOWS HOLD IN THE TEENS SUNDAY AND MONDAY NIGHT.
THE NEXT LOW PRESSURE SYSTEM APPEARS TO BE SHAPING UP TO BE A
STRONGER SYSTEM THAN THE WEEKEND EVENT...WITH A TRACK THAT WOULD
SUPPORT A WIDE VARIETY OF PRECIPITATION ACROSS THE CWA ON TUESDAY
WITH PRIMARILY SNOW OVER THE NORTHERN CWA AND SNOW CHANGING TO A MIX
AND THEN EVENTUALLY RAIN FURTHER SOUTH. WITH THE EVENTUAL TRACK AND
STRENGTH OF THIS SYSTEM STILL IN DOUBT...WILL FORGO ANY SIGNIFICANT
DETAILS AT THIS TIME...OTHER THAN TO INCLUDE SOME MENTION OF
SLEET...FREEZING RAIN AND RAIN AS 00Z RUNS OF THE GFS...CMC AND
ECMWF DO NOT SUPPORT AN ALL SNOW EVENT FOR THE ENTIRE CWA.
MARINE...
HIGH PRESSURE WILL BE BUILD FROM THE MID MISSISSIPPI VALLEY TODAY
THROUGH THE OHIO VALLEY ON SATURDAY. MODEST SOUTHWEST RETURN FLOW
WILL DEVELOP AROUND THIS HIGH OVER THE CENTRAL GREAT LAKES. CENTRAL
SECTIONS OF LAKE HURON WILL MOST LIKELY SEE WINDS INCREASE INTO THE
15 TO 20 KNOT RANGE. OTHERWISE...WINDS WILL REMAIN ON THE LIGHT SIDE
AS THIS SOUTHWEST PRESSURE GRADIENT WEAKENS LATE IN THE WEEKEND AS A
WEAK LOW PRESSURE SYSTEM LIFTS INTO THE REGION. EVEN THE RETURN OF
COLD NORTHWEST FLOW IN THE WAKE OF THE ATTENDING COLD FRONT WILL BE
LIMITED TO 25 KNOT GUSTS OR LESS OVER MUCH OF LAKE HURON.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&
$$
UPDATE.......SF
AVIATION.....99
SHORT TERM...CB
LONG TERM....DG
MARINE.......DG
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
619 AM EST FRI FEB 27 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 402 AM EST FRI FEB 27 2015
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A NW FLOW ALOFT
OVER THE UPR GREAT LKS TO THE SW OF CLOSED H5 LO OVER NRN QUEBEC.
SHRTWV RDG AXIS STRETCHING FM THE NRN PLAINS INTO NW ONTARIO IS
SUPPORTING A SFC HI PRES STRETCHING FM THE NRN PLAINS INTO IOWA. UPR
MI IS DOMINATED BY A DRY WNW LLVL FLOW E OF THIS HI CENTER /00Z
PWATS UPSTREAM ARE GENERALLY 0.05 TO 0.10 INCH...NO MORE THAN 50 PCT
OF NORMAL/. COMBINATION OF THE DRYNESS OF THE UPSTREAM AIRMASS...00Z
INL AND YPL RAOBS SHOW AN INVERTED V T/TD PROFILE BLO SUBSIDENCE
INVRN NEAR H9...AND EXTENSIVE ICE COVER OVER LK SUP HAS GREATLY
DIMINISHED THE LES. IN FACT...IR STLT IMAGERY SHOWS ONLY PATCHY LK
CLDS STREAMING INTO AREAS E OF MUNISING. 00Z H85 TEMPS OVER THE AREA
RANGE FM -23C AT GRB TO -19C AT INL/YPL AND THEN UP TO -16C AT THE
PAS MANITOBA. UNDER THE MOCLR SKIES/DRY ARCTIC AIRMASS...TEMPS HAVE
FALLEN WELL BLO ZERO OVER THE INTERIOR AND AS LO AS -25F TO -30F AT
THE MORE SHELTERED RURAL SPOTS. WINDS ARE STIRRING A BIT MORE NEAR
LK SUP UNDER A TIGHTER PRES GRADIENT...AND SOME OF THE MORE EXPOSED
LOCATIONS THERE ARE INDICATING WIND CHILLS AS LO AS -25F.
MAIN FCST CONCERNS THRU TNGT WL BE ON TEMPS. OPTED TO ISSUE AN SPS
TO COVER WIND CHILLS NEAR ADVY CRITERIA AT THE MORE EXPOSED
LOCATIONS NEAR LK SUP THIS MRNG.
TODAY...AS SHRTWV RDG TO THE NW SLIDES TO THE SE...SFC HI PRES
CENTER IS FCST TO SHIFT TO INDIANA/ILLINOIS BY 00Z SAT. THE
COMBINATION OF ONGOING SUBSIDENCE AHEAD OF THE SHRTWV RDG AND SOME
WAA AS THE SFC-H925 FLOW BACKS TO THE WSW...IS FCST TO RAISE H85
TEMPS UP TO -16 TO -17C BY THE END OF THE DAY. GIVEN ABSENCE OF MUCH
DIURNAL CU UPSTREAM YDAY AND LARGER SCALE SUBSIDENCE/WRMG AT H85...
SUSPECT THERE WL ONLY BE SOME SCT DIURNAL CLDS OVER THE INTERIOR
THIS AFTN. AS THE FLOW BACKS...LINGERING LK CLDS/ANY FLURRIES E OF
MUNISING THIS MRNG SHOULD SHIFT OUT OVER LK SUP IN THE AFTN. WITH A
GOOD DEAL OF SUNSHINE...GOING FCST HI TEMPS RECOVERING INTO THE
TEENS APPEAR TO BE ON TRACK.
TNGT...SFC HI PRES IS FCST TO SLIDE INTO THE MID ATLANTIC STATES BY
12Z SUN...WITH STEADY WSW WIND REMAINING IN PLACE UNDER THE TIGHT
PRES GRADIENT TO THE NW OF THIS FEATURE. ALOFT...UPR MI BE UNDER
CONTINUED SUBSIDENCE AHEAD OF ANOTHER SHRTWV RDG APRCHG FM THE W.
WITH A CONTINUED SLOW WARMING OF THE H85 TEMPS...AN ABSENCE OF ANY
SGNFT LLVL MSTR INFLOW AND GENERALY ACYC NATURE OF THE W FLOW...LK
CLDS OVER THE KEWEENAW SHOULD BE SCT AT BEST. ANY LK CLDS/LES OVER
THE E HALF OF THE LK SHOULD REMAIN OFFSHORE. PWAT IS FCST TO BE AOB
0.10 INCH...SO TENDED TO GO AOB THE LO END OF GUIDANCE FOR MIN TEMPS
/AS IS OBSVD THIS MRNG/ IN AREAS AWAY FM LK SUP...WHERE A STEADIER
WIND SHOULD LIMIT THE DIURNAL TEMP DROP.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 402 AM EST FRI FEB 27 2015
SATURDAY INTO SATURDAY NIGHT...A BROAD SURFACE HIGH PRESSURE SYSTEM
OVER MUCH OF THE GREAT LAKES REGION WILL REMAIN IN PLACE THROUGH THE
DAY SATURDAY. THIS WILL KEEP FAIRLY DRY AIR IN PLACE ALLOWING MOST
AREAS OF THE U.P. TO SEE SUNNY SKIES THROUGH THE DAY SATURDAY. BY
SATURDAY NIGHT...THE HIGH PRESSURE CENTER WILL SHIFT EASTWARD
STRETCHING FROM THE NORTHEAST U.S. SOUTHWARD ALONG THE EASTERN
SEABOARD. AT THIS HAPPENS...A WEAK SURFACE TROUGH/COLD FRONT WILL
APPROACH THE AREA FROM THE WEST. OVERALL MOISTURE APPEARS TO BE
LIMITED AND FOCUSED MAINLY TO THE SOUTH OF THE U.P. THEREFORE...ONLY
EXPECTING AN INCREASE IN CLOUD COVER SATURDAY NIGHT WITH ONLY A
SMALL CHANCE OF LIGHT SNOW ACROSS THE U.P. WITH LIMITED/WEAK FORCING.
SUNDAY THROUGH MONDAY...THE SURFACE TROUGH/WEAK COLD FRONT WILL
CONTINUE TO SHIFT EASTWARD AND PASS THROUGH THE UPPER PENINSULA
THROUGH THE DAY SUNDAY. AGAIN...MOISTURE WILL BE LIMITED ALONG THE
FRONT WITH CONTINUED WEAK FORCING. ONLY LIGHT SNOW IS EXPECTED
THROUGH THE DAY SUNDAY. BEHIND THE FRONT...AN UPPER LEVEL 500MB
TROUGH IS POISED TO SWING ACROSS THE U.P. SUNDAY NIGHT. AS THIS
HAPPENS...ENOUGH MOISTURE WILL REMAIN IN PLACE WITH VERY SLIGHT
ADDITIONAL MOISTURE ADDED FROM THE ICE COVER LAKE SUPERIOR TO ALLOW
A CHANCE OF LAKE EFFECT SNOW SHOWERS TO DEVELOP FOR WEST TO
NORTHWEST WIND FAVORED LOCATIONS. DELTA T VALUES WILL BE SUFFICIENT
FOR LAKE EFFECT WITH THE TROUGH AXIS SLIDING ACROSS...BUT LAKE
EFFECT INTENSITY WILL BE LIMITED TO AREAS THAT ANY BREAKS IN THE ICE
COVER OCCURS. ANY LAKE EFFECT THAT IS ABLE TO DEVELOP SUNDAY NIGHT
WILL BE SHORT LIVED AS MUCH DRIER AIR AND HIGH PRESSURE AT THE
SURFACE AND SLIGHT RIDGING ALOFT TO PUSH INTO THE UPPER GREAT LAKES
REGION DURING THE DAY MONDAY. THIS WILL FOR MAINLY SUNNY SKIES
DURING THE DAY MONDAY.
MONDAY NIGHT THROUGH WEDNESDAY...THE AFOREMENTIONED HIGH PRESSURE
SYSTEM WILL SHIFT TO THE LOWER GREAT LAKES...THEN THE EASTERN
SEABOARD MONDAY NIGHT. THIS WILL ALLOW A MORE MOIST SOUTHERLY FLOW
TO DEVELOP ON THE BACK SIDE OF THE HIGH. AT THE SAME TIME...A LOW
PRESSURE SYSTEM IS PROGGED TO DEVELOP OVER THE FOUR CORNERS REGION
OF THE U.S. ADDITIONALLY...ANOTHER STRONGER WAVE OF ENERGY IS
PROGGED TO PUSH ACROSS CENTRAL CANADA AND WORK TOWARD THE JAMES BAY
AREA. THERE ARE MODEL DIFFERENCES WITH THE PHASING OF THE TWO
SYSTEMS. THE 18Z/26 00Z/27 GFS IS MORE PROGRESSIVE WITH BOTH
SYSTEMS AND THE PHASING OF THE SYSTEMS. THIS WOULD PUSH SNOW INTO
THE AREA AS EARLY AS MONDAY EVENING ON ISENTROPIC UPGLIDE AND
INCREASED MOISTURE IN THE AREA. THE EC 12/26 00Z/27 IS MUCH SLOWER
WITH THE PHASING...KEEPING THE PRECIPITATION OUT OF THE AREA UNTIL
LATE MONDAY NIGHT INTO TUESDAY MORNING. THE BEST CHANCES GIVEN THE
OVERLAP OF THE TWO MODEL SOLUTIONS WOULD BE TUESDAY AFTERNOON INTO
TUESDAY NIGHT...ESPECIALLY FOR THE EAST HALF OF THE U.P. AT THIS
POINT...WILL STICK WITH CHANCE POPS AT LEAST UNTIL THE SYSTEM IS
SAMPLED BETTER OVER THE NEXT FEW DAYS.
WEDNESDAY NIGHT AND THURSDAY...BOTH THE EC AND GFS AGREE ON AN UPPER
LEVEL TROUGH AXIS ALONG WITH DEEPER MOISTURE LINGERING ACROSS THE
AREA DURING THIS TIME PERIOD. THE COLDER TEMPERATURES ALOFT ALONG
WITH ANY ADDITIONAL MOISTURE OFF LAKE SUPERIOR WILL ALLOW FOR LAKE
EFFECT SNOW CHANCES. AGAIN...THE EXACT LOCATION ALONG WITH INTENSITY
WILL BE LARGELY TIED TO ANY BREAKS IN THE ICE COVER ON LAKE
SUPERIOR. THE FAVORED LOCATIONS BASED SOLELY ON WIND WOULD BE FOR
THE WEST TO WEST NORTHWEST WIND FAVORED SNOW BELTS. GENERALLY...ANY
LAKE EFFECT SNOW SHOULD REMAIN FAIRLY LIGHT.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 618 AM EST FRI FEB 27 2015
WITH DRY HI PRES DOMINATING...EXPECT VFR CONDITIONS TO PREDOMINATE
AT THE TAF SITES THIS FCST PERIOD. NOT OUT OF THE QUESTION THERE
COULD BE SOME MVFR CIGS AS DIURNAL CU/SC DEVELOP LATE THIS MRNG/
AFTN...BUT ABSENCE OF THESE CLDS UPSTREAM YDAY...RELATIVELY LO
SUBSIDENCE INVRN BASE AND ICE COVER ON LK SUP THAT WL RESTRICT
MOISTENING OF THE AIRMASS INDICATE THE CHC IS TOO LO TO INCLUDE IN
THE TAFS.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 402 AM EST FRI FEB 27 2015
EXPECT WINDS TO BE UNDER 30 KTS THIS FORECAST PERIOD. LAKE SUPERIOR
IS MAINLY ICE COVERED THIS MORNING. ALTHOUGH SHIFTING WINDS UP TO 20
TO 25 KTS ACCOMPANYING THE PASSAGE OF DISTURBANCES THRU THE UPPER
LAKES MAY CAUSE HOLES TO OPEN IN THE ICE FROM TIME TO TIME...A
CONTINUED DOMINANCE OF ARCTIC AIR WILL MAINTAIN AN OVERALL EXTENSIVE
ICE COVER.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...KEC
AVIATION...KC
MARINE...KC
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
550 AM EST FRI FEB 27 2015
.AVIATION...
SURFACE HIGH PRESSURE BUILDING EASTWARD INTO THE REGION WILL
CONTINUE TO SUPPORT A VERY DRY AIR MASS. WIND DIRECTIONS ARE
FORECASTED TO EMERGE SOUTHWESTERLY TODAY...BRINGING THE POTENTIAL
FOR LAKE MICHIGAN MOISTURE TO WORK UNDER THE INVERSION BASE AT 4-5
KFT AGL. MODEL SOUNDINGS ALSO SUPPORT A DIURNAL COMPONTENT TO
POTENTIAL CLOUD COVER. DOWNSTREAM TRAJECTORY CONTINUES TO SUPPORT
THE BEST POTENTIAL FOR THE NORTHERN TAF SITES.
//DTW THRESHOLD PROBABILITIES...
* LOW CONFIDENCE IN CEILING BELOW 5000 FT FRIDAY AFTERNOON.
&&
.PREV DISCUSSION...ISSUED 358 AM EST FRI FEB 27 2015
SHORT TERM...TODAY AND TONIGHT
RECORD LOWS FOR FEB 27
DETROIT AREA: -4 (1934)
FLINT AREA: -14 (1994)
SAGINAW: -8 (1934)
ANOTHER COLD MORNING ACROSS SOUTHEASTERN MICHIGAN WITH AN ARCTIC
SURFACE RIDGE LOCKED IN OVERHEAD. NIL WIND AND CLEAR SKIES HAS LED
TO FAVORABLE RADIATIVE COOLING CONDITIONS. SURFACE TEMPERATURES
CURRENTLY RANGE FROM 0 TO 10 DEGREES BELOW ZERO AS OF 3AM. WITH A
LACK OF LOW CLOUD DISCERNIBLE IN IR IMAGERY...EXPECTATIONS ARE FOR
SURFACE TEMPERATURES TO CONTINUE TO BOTTOM OUT BEFORE SUNRISE WITH
MANY RURAL LOCATIONS REACHING 10 TO 20 DEGREES BELOW ZERO. WITH A
DECOUPLED SURFACE LAYER...WILL HONOR THE DECISION OF PRIOR SHIFTS
AND NOT ISSUE A WIND CHILL ADVISORY.
COLDEST MIDLEVEL TEMPERATURES PUSHING OUT OF THE STATE TODAY IN
COMBINATION WITH AN SURFACE ANTICYCLONE PUSHING INTO PORTIONS OF
OHIO WILL ALLOW WIND DIRECTIONS OVER SOUTHEASTERN MICHIGAN TO MAKE A
CONCERTED MOVE TO SOUTHWESTERLY. ENHANCED MOISTURE AND LAKE MICHIGAN
CLOUD DEBRIS IS PROGGED TO STREAM EASTWARD WITH TIME...SHOWN TO
SLIDE THROUGH PORTIONS OF THE CWA BY THIS AFTERNOON AND INTO THE
EARLY EVENING. RAP SOUNDINGS SUGGEST THERE WILL BE A CONSIDERABLE
DIURNAL COMPONENT TO ANY SKY COVER. WIND TRAJECTORIES POINT TO THE
NORTHERN CWA/SAGAINAW VALLEY AS THE MORE FAVORABLE LOCATION FOR
CLOUDS. WITH SUN...SHADED A DEGREE OR TWO HIGHER THAN MOS GUIDANCE
FOR HIGHS.
SURFACE HIGH PRESSURE PUSHING THROUGH INDIANA AND OHIO WILL SET
ANOTHER NIGHT UP FOR CALM WINDS ACROSS THE SOUTHERN HALF OF THE CWA.
LOWERED MINS FOR AREAS SOUTH OF DETROIT. OTHERWISE...A PRESSURE
GRADIENT IN PLACE OVER THE TRI CITIES/NORTHERN THUMB AND SOME
POTENTIAL FOR LINGERING CLOUDS LIMITS THE TEMPERATURE FALL POTENTIAL
FOR TONIGHT.
LONG TERM...
COLD AIRMASS WILL REMAIN IN PLACE INTO EARLY THIS WEEKEND ALTHOUGH
TEMPERATURES WILL MODERATE EVER SO SLIGHTLY AS THE LATEST ARCTIC
HIGH PRESSURE SHIFTS TO THE EAST OF THE AREA SATURDAY NIGHT. HIGHS
ON SATURDAY WILL CLIMB TO AROUND 20F WITH LOWS THAT NIGHT HOLDING
INTO THE SINGLE DIGITS TO NEAR 10F AS BOTH THE COLDEST AIR SHIFTS
EAST AND EXPANDING CLOUD COVER WORKS INTO THE AREA WITH THE APPROACH
OF A LOW PRESSURE SYSTEM.
00Z MODEL RUNS...SAVE THE NAM12...BASICALLY SUPPORT THE PREVIOUS
FORECAST AS ROUGHLY 1 TO 2 INCHES OF SNOW FALL FROM THE I-69
CORRIDOR NORTH LATE SATURDAY NIGHT INTO EARLY SUNDAY EVENING WITH 2
TO 3 INCHES SOUTH OF THAT INTO METRO DETROIT AS H7 SPECIFIC HUMIDITY
CLIMBS TO AROUND 2 G/KG ALONG THE M-59 CORRIDOR. GIVEN THE
RELATIVELY HIGH SNOW TO LIQUID RATIOS EXPECTED WITH THE COLD AIRMASS
IN PLACE...15:1 OR A BIT MORE...WOULD NOT BE SURPRISED TO SEE UP TO
4 INCHES FROM THE I-94 CORRIDOR SOUTHWARD.
TEMPERATURES WILL EDGE BACK DOWN EARLY NEXT WEEK...BUT TO MUCH MORE
REASONABLE LEVELS THAN THE PAST SEVERAL WEEKS AS HIGHS MONDAY REACH
THE MID/UPPER 20S AND LOWS HOLD IN THE TEENS SUNDAY AND MONDAY NIGHT.
THE NEXT LOW PRESSURE SYSTEM APPEARS TO BE SHAPING UP TO BE A
STRONGER SYSTEM THAN THE WEEKEND EVENT...WITH A TRACK THAT WOULD
SUPPORT A WIDE VARIETY OF PRECIPITATION ACROSS THE CWA ON TUESDAY
WITH PRIMARILY SNOW OVER THE NORTHERN CWA AND SNOW CHANGING TO A MIX
AND THEN EVENTUALLY RAIN FURTHER SOUTH. WITH THE EVENTUAL TRACK AND
STRENGTH OF THIS SYSTEM STILL IN DOUBT...WILL FORGO ANY SIGNIFICANT
DETAILS AT THIS TIME...OTHER THAN TO INCLUDE SOME MENTION OF
SLEET...FREEZING RAIN AND RAIN AS 00Z RUNS OF THE GFS...CMC AND
ECMWF DO NOT SUPPORT AN ALL SNOW EVENT FOR THE ENTIRE CWA.
MARINE...
HIGH PRESSURE WILL BE BUILD FROM THE MID MISSISSIPPI VALLEY TODAY
THROUGH THE OHIO VALLEY ON SATURDAY. MODEST SOUTHWEST RETURN FLOW
WILL DEVELOP AROUND THIS HIGH OVER THE CENTRAL GREAT LAKES. CENTRAL
SECTIONS OF LAKE HURON WILL MOST LIKELY SEE WINDS INCREASE INTO THE
15 TO 20 KNOT RANGE. OTHERWISE...WINDS WILL REMAIN ON THE LIGHT SIDE
AS THIS SOUTHWEST PRESSURE GRADIENT WEAKENS LATE IN THE WEEKEND AS A
WEAK LOW PRESSURE SYSTEM LIFTS INTO THE REGION. EVEN THE RETURN OF
COLD NORTHWEST FLOW IN THE WAKE OF THE ATTENDING COLD FRONT WILL BE
LIMITED TO 25 KNOT GUSTS OR LESS OVER MUCH OF LAKE HURON.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&
$$
AVIATION.....99
SHORT TERM...CB
LONG TERM....DG
MARINE.......DG
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
758 AM EST FRI FEB 27 2015
.SYNOPSIS...
A LARGE AREA OF HIGH PRESSURE WILL BUILD ACROSS THE AREA THROUGH
THE FIRST HALF OF THE WEEKEND. A LOW PRES SYSTEM WILL LIFT OUT OF
THE MIDWEST LATE IN THE WEEKEND...PASSING OVER THE REGION SUNDAY
NIGHT. A STRONGER AREA OF LOW PRESSURE WILL LIKELY TRACK WEST OF
PENNSYLVANIA LATE TUESDAY OR EARLY WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AT 11Z RADAR CONTINUES TO SHOW PATCHY LIGHT SNOW FALLING FROM
ARND KUNV SEWRD INTO THE LOWER SUSQ VALLEY ALONG AXIS OF INVERTED
SFC TROF. RETURNS SHOULD CONTINUE TO DIMINISH...AS DRIER AIR
WORKS IN. BLEND OF LATEST HRRR AND 4KM NAM INDICATE ANY ACCUMS
AFTER 12Z WILL BE NEGLIGIBLE. SATL IMAGERY SHOWS CLEARING SKIES
ACROSS NORTHWEST PA EARLY THIS AM...AS DRY...ARCTIC AIR MASS
OVERSPREADS THE AREA. EXPECT THIS PARTIAL CLEARING TO PROGRESS
INTO THE EASTERN HALF OF THE STATE LATER THIS MORNING.
UPSTREAM OBS SUGGEST SKIES MAY BECOME MOSUNNY FOR A WHILE THIS
MORNING. HOWEVER...DIURNAL HEATING...COMBINED WITH COLD POOL
ALOFT...SHOULD YIELD A FAIR AMT OF STRATO CU THIS AFTN...ESP OVR
THE ALLEGHENY PLATEAU. GEFS MEAN 925MB TEMPS ARND -15C SHOULD
TRANSLATE TO HIGHS NO BETTER THAN ARND 10F ACROSS THE HIGHER
TERRAIN OF THE ALLEGHENIES...TO THE L/M20S ACROSS THE SUSQ VALLEY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/...
CLEARING SKIES...A CALM WIND AND SNOW COVER WILL LIKELY RESULT IN
THE LOWEST TEMPS UNTIL NEXT WINTER TONIGHT AS THE CENTER OF HIGH
PRESSURE MOVES OVER PENN.
THE IDEAL RADIATIONAL COOLING CONDS SHOULD ALLOW READINGS TO
BOTTOM OUT FROM 10-15F BELOW ZERO ACROSS THE WESTERN MTNS...TO
0-5F ABV ZERO ACROSS THE LOWER SUSQ VALLEY. THE COLDEST RURAL
VALLEYS IN NW AND NCENT PENN COULD SEE THE MERCURY SETTLE TO
AROUND -20F AT 11-12Z SATURDAY. SOME LOCATIONS ACROSS THE NW MTNS
ARE LIKELY REACH WCHILL ADVISORY CRITERIA...DESPITE A LIGHT/CALM
WIND. HOWEVER...CONFIDENCE IN WIDESPREAD APPARENT TEMPS BLW -15F
NOT THERE YET FOR AN ADVISORY.
FAIR AND STILL COLD WEATHER EXPECTED SATURDAY...AS SFC HIGH
DRIFTS OVR THE AREA. A FAST-MOVING MID LVL SHORTWAVE IS PROGGED BY
ALL MDLS TO TRACK ACROSS THE AREA LATE IN THE DAY. LOW PWAT AIR
MASS WILL PRECLUDE ANY PRECIP CONCERNS. HOWEVER...CIRRUS MAY DIM
THE SUNSHINE AT TIMES. ENS MEAN 850/925MB TEMPS REMAIN WELL BLW
NORMAL FOR THE DATE...LIKELY SUPPORTING HIGHS ONLY IN THE 20-25F
RANGE.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
A RELATIVELY MILD/ACTIVE SOUTHWEST FLOW ALOFT SHOULD PREVAIL
THROUGH THE PERIOD AS THE PERSISTENT UPPER RIDGE OVER THE WRN
U.S. TEMPORARILY BREAKS DOWN. AN ARCTIC HIGH PRESSURE SYSTEM OVER
CENTRAL PA AT THE START OF THE PERIOD WILL RETREAT INTO ATLANTIC
CANADA BY SUNDAY NIGHT. THE COMBINATION OF SHORTWAVE ENERGY IN THE
SRN STREAM EJECTING FROM A DSW TROUGH AND A DIGGING NRN STREAM
TROUGH MOVING SEWD FROM SOUTH CENTRAL CANADA TOWARD THE UPPER
MIDWEST SEEMS TO DRIVE AN EXPANDING AREA OF WAA TYPE SNOWFALL
SPREADING EASTWARD SUN-MON BEHIND THE SOUTHERLY RETURN FLOW INTO
A RETREATING COLD SECTOR ASSOCD WITH THE DEPARTING ARCTIC HIGH.
THE PCPN SHOULD BE ENHANCED ALONG AN EXPANDING BAROCLINIC ZONE
ACROSS THE CENTRAL AND EASTERN US...AS UPPER RIDGING BUILDS OVER
THE SE U.S.
WHILE THERE APPEARS TO BE LITTLE INDICATION OF A STRONG SURFACE
LOW...MODELS STILL GENERATE 0.25-0.50 INCH QPF AMTS ALONG THE
BAROCLINIC ZONE. THERMAL PROFILES SEEM TO FAVOR SNOW ACROSS THE NW
1/2 OF CENTRAL PA WITH MIXED PTYPES IN THE SOUTH/SOUTHEAST.
PRELIMINARY 24HR SNOW/ICE AMOUNTS WERE DERIVED USING A MULTI
MODEL QPF BLEND WITH PSEUDO INTERNAL BIAS CORRECTION FACTOR AND
WPC WWD. THIS RESULTS IN ADVY LEVEL SNOWFALL OVER THE NW 1/2 AND
0.10 INCH ICE/ZR OVER THE LWR SUSQ VLY. CONFIDENCE IN THE AMTS IS
AVG AT BEST GIVEN UNCERTAINTY IN QPF AND LOW-LEVEL TEMPERATURES.
THE LACK OF A DEFINED SFC CYCLONE ALSO RAISES SOME REG FLAGS.
ANOTHER COLD HP SYSTEM BUILDS INTO THE REGION MON-TUE WITH ANOTHER
SW FLOW WAA MSTR SURGE ALONG BAROCLINIC FRONTAL ZONE LKLY
IMPACTING THE AREA INTO THE MIDDLE OF NEXT WEEK. TIMING
DIFFERENCES ARE EVIDENT WITH THE GFS MORE BULLISH ON PCPN
RETURNING EARLY TUE VS. SLOWER ECMWF (TUE NGT). MIXED PTYPE ISSUES
ARE EXPECTED AGAIN WITH THIS NEXT SYSTEM.
&&
.AVIATION /13Z FRIDAY THROUGH TUESDAY/...
PATCHY LIGHT SNOW CONTINUES TO QUICKLY ERODE FROM KUNV SEWRD INTO
THE LOWER SUSQ VALLEY ALONG AXIS OF INVERTED SFC TROF...AS DRIER
ARCTIC AIR WORKS IN FROM THE WEST.
CLEARING SKIES ACROSS NORTHWEST PA EARLY THIS AM SHOULD FILL BACK
IN WITH COLD POOL STRATOCU MVFR CIGS FOR SEVERAL HOURS THIS
MORNING THROUGH EARLY AFTERNOON...WITH OROGRAPHIC FLOW ALSO
KEEPING LIGHT SNOW AND LOW CIGS/VSBYS IN KJST THROUGH AT LEAST
EARLY AFTERNOON. REMAINDER OF THE AREA WILL BE OR TRANSITION TO
VFR CONDITIONS OVER NEXT FEW HOURS AS ANOMALOUSLY STRONG
1040-1045 MB SFC HIGH PRESSURE BUILDS IN FROM THE OHIO VALLEY.
WINDS WILL BE W/NW AT AROUND 10 MPH.
OUTLOOK...
FRI NIGHT AND SAT...NO SIG WX EXPECTED.
SUN...SNOW LIKELY NW MTNS. MIXED PRECIP POSSIBLE ELSEWHERE.
MON...MIXED PRECIP WITH CIG/VIS REDUCTIONS POSSIBLE...MAINLY AM.
TUE...VFR AM. MIXED PRECIP WITH CIG/VIS REDUCTIONS POSSIBLE LATE.
&&
.CLIMATE...
THE COLDEST FEBRUARY ON RECORD IS STILL LOOKING LIKELY. MONTHLY
MEAN TEMPERATURES THROUGH THE 26TH...IPT 18.2...MDT 20.7.
THE CURRENT RECORD COLDEST FEBRUARY..IPT 19.3...MDT 21.4 BOTH SET
IN 1934.
SO FAR...THIS MONTH IS THE THIRD COLDEST EVER AT IPT...AND FOURTH
COLDEST EVER AT MDT.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...FITZGERALD
NEAR TERM...FITZGERALD
SHORT TERM...FITZGERALD
LONG TERM...FITZGERALD/STEINBUGL
AVIATION...RXR
CLIMATE...
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
643 AM EST FRI FEB 27 2015
.SYNOPSIS...
A LARGE AREA OF HIGH PRESSURE WILL BUILD ACROSS THE AREA THROUGH
THE FIRST HALF OF THE WEEKEND. A LOW PRES SYSTEM WILL LIFT OUT OF
THE MIDWEST LATE IN THE WEEKEND...PASSING OVER THE REGION SUNDAY
NIGHT. A STRONGER AREA OF LOW PRESSURE WILL LIKELY TRACK WEST OF
PENNSYLVANIA LATE TUESDAY OR EARLY WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AT 11Z RADAR CONTINUES TO SHOW PATCHY LIGHT SNOW FALLING FROM
ARND KUNV SEWRD INTO THE LOWER SUSQ VALLEY ALONG AXIS OF INVERTED
SFC TROF. RETURNS SHOULD CONTINUE TO DIMINISH...AS DRIER AIR
WORKS IN. BLEND OF LATEST HRRR AND 4KM NAM INDICATE ANY ACCUMS
AFTER 12Z WILL BE NEGLIGIBLE. SATL IMAGERY SHOWS CLEARING SKIES
ACROSS NORTHWEST PA EARLY THIS AM...AS DRY...ARCTIC AIR MASS
OVERSPREADS THE AREA. EXPECT THIS PARTIAL CLEARING TO PROGRESS
INTO THE EASTERN HALF OF THE STATE LATER THIS MORNING.
UPSTREAM OBS SUGGEST SKIES MAY BECOME MOSUNNY FOR A WHILE THIS
MORNING. HOWEVER...DIURNAL HEATING...COMBINED WITH COLD POOL
ALOFT...SHOULD YIELD A FAIR AMT OF STRATO CU THIS AFTN...ESP OVR
THE ALLEGHENY PLATEAU. GEFS MEAN 925MB TEMPS ARND -15C SHOULD
TRANSLATE TO HIGHS NO BETTER THAN ARND 10F ACROSS THE HIGHER
TERRAIN OF THE ALLEGHENIES...TO THE L/M20S ACROSS THE SUSQ VALLEY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/...
CLEARING SKIES...A CALM WIND AND SNOW COVER WILL LIKELY RESULT IN
THE LOWEST TEMPS UNTIL NEXT WINTER TONIGHT AS THE CENTER OF HIGH
PRESSURE MOVES OVER PENN.
THE IDEAL RADIATIONAL COOLING CONDS SHOULD ALLOW READINGS TO
BOTTOM OUT FROM 10-15F BELOW ZERO ACROSS THE WESTERN MTNS...TO
0-5F ABV ZERO ACROSS THE LOWER SUSQ VALLEY. THE COLDEST RURAL
VALLEYS IN NW AND NCENT PENN COULD SEE THE MERCURY SETTLE TO
AROUND -20F AT 11-12Z SATURDAY. SOME LOCATIONS ACROSS THE NW MTNS
ARE LIKELY REACH WCHILL ADVISORY CRITERIA...DESPITE A LIGHT/CALM
WIND. HOWEVER...CONFIDENCE IN WIDESPREAD APPARENT TEMPS BLW -15F
NOT THERE YET FOR AN ADVISORY.
FAIR AND STILL COLD WEATHER EXPECTED SATURDAY...AS SFC HIGH
DRIFTS OVR THE AREA. A FAST-MOVING MID LVL SHORTWAVE IS PROGGED BY
ALL MDLS TO TRACK ACROSS THE AREA LATE IN THE DAY. LOW PWAT AIR
MASS WILL PRECLUDE ANY PRECIP CONCERNS. HOWEVER...CIRRUS MAY DIM
THE SUNSHINE AT TIMES. ENS MEAN 850/925MB TEMPS REMAIN WELL BLW
NORMAL FOR THE DATE...LIKELY SUPPORTING HIGHS ONLY IN THE 20-25F
RANGE.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
A RELATIVELY MILD/ACTIVE SOUTHWEST FLOW ALOFT SHOULD PREVAIL
THROUGH THE PERIOD AS THE PERSISTENT UPPER RIDGE OVER THE WRN
U.S. TEMPORARILY BREAKS DOWN. AN ARCTIC HIGH PRESSURE SYSTEM OVER
CENTRAL PA AT THE START OF THE PERIOD WILL RETREAT INTO ATLANTIC
CANADA BY SUNDAY NIGHT. THE COMBINATION OF SHORTWAVE ENERGY IN THE
SRN STREAM EJECTING FROM A DSW TROUGH AND A DIGGING NRN STREAM
TROUGH MOVING SEWD FROM SOUTH CENTRAL CANADA TOWARD THE UPPER
MIDWEST SEEMS TO DRIVE AN EXPANDING AREA OF WAA TYPE SNOWFALL
SPREADING EASTWARD SUN-MON BEHIND THE SOUTHERLY RETURN FLOW INTO
A RETREATING COLD SECTOR ASSOCD WITH THE DEPARTING ARCTIC HIGH.
THE PCPN SHOULD BE ENHANCED ALONG AN EXPANDING BAROCLINIC ZONE
ACROSS THE CENTRAL AND EASTERN US...AS UPPER RIDGING BUILDS OVER
THE SE U.S.
WHILE THERE APPEARS TO BE LITTLE INDICATION OF A STRONG SURFACE
LOW...MODELS STILL GENERATE 0.25-0.50 INCH QPF AMTS ALONG THE
BAROCLINIC ZONE. THERMAL PROFILES SEEM TO FAVOR SNOW ACROSS THE NW
1/2 OF CENTRAL PA WITH MIXED PTYPES IN THE SOUTH/SOUTHEAST.
PRELIMINARY 24HR SNOW/ICE AMOUNTS WERE DERIVED USING A MULTI
MODEL QPF BLEND WITH PSEUDO INTERNAL BIAS CORRECTION FACTOR AND
WPC WWD. THIS RESULTS IN ADVY LEVEL SNOWFALL OVER THE NW 1/2 AND
0.10 INCH ICE/ZR OVER THE LWR SUSQ VLY. CONFIDENCE IN THE AMTS IS
AVG AT BEST GIVEN UNCERTAINTY IN QPF AND LOW-LEVEL TEMPERATURES.
THE LACK OF A DEFINED SFC CYCLONE ALSO RAISES SOME REG FLAGS.
ANOTHER COLD HP SYSTEM BUILDS INTO THE REGION MON-TUE WITH ANOTHER
SW FLOW WAA MSTR SURGE ALONG BAROCLINIC FRONTAL ZONE LKLY
IMPACTING THE AREA INTO THE MIDDLE OF NEXT WEEK. TIMING
DIFFERENCES ARE EVIDENT WITH THE GFS MORE BULLISH ON PCPN
RETURNING EARLY TUE VS. SLOWER ECMWF (TUE NGT). MIXED PTYPE ISSUES
ARE EXPECTED AGAIN WITH THIS NEXT SYSTEM.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
LARGE-SCALE FORCING AHEAD OF A SHORTWAVE OVER THE GREAT LAKES
BRINGING SOME LIGHT SNOW TO PORTIONS OF CENTRAL MTNS EARLY THIS
MORNING. THIS WILL REDUCE VSBYS/CIGS TO MVFR /OCCASIONAL IFR/
PRIMARILY OVER THE WESTERN HIGHER TERRAIN THROUGH 12Z. BRIEF
PERIOD OF MVFR CIGS POSS FURTHER EAST THROUGH 10Z.
ANOTHER PUSH OF ARCTIC AIR ARRIVES IMMEDIATELY BEHIND THE
SHORTWAVE FOR FRI. OROGRAPHIC FLOW WILL KEEP MVFR CONDITIONS IN
WESTERN HIGHER TERRAIN THROUGH MIDDAY...WITH IMPROVING CONDITIONS
IN THE AFTERNOON AS ANOMALOUSLY STRONG 1040-1045 MB SFC HIGH
PRESSURE BUILDS INTO THE COMMONWEALTH FROM THE OHIO VALLEY. VFR
WILL BE THE RULE IN CENTRAL AND EAST. WINDS WILL BE W/NW AT AROUND
10 MPH.
OUTLOOK...
FRI NIGHT AND SAT...NO SIG WX EXPECTED.
SUN...SNOW LIKELY NW MTNS. MIXED PRECIP POSSIBLE ELSEWHERE.
MON...MIXED PRECIP WITH CIG/VIS REDUCTIONS POSSIBLE...MAINLY AM.
TUE...VFR AM. MIXED PRECIP WITH CIG/VIS REDUCTIONS POSSIBLE LATE.
&&
.CLIMATE...
THE COLDEST FEBRUARY ON RECORD IS STILL LOOKING LIKELY. MONTHLY
MEAN TEMPERATURES THROUGH THE 26TH...IPT 18.2...MDT 20.7.
THE CURRENT RECORD COLDEST FEBRUARY..IPT 19.3...MDT 21.4 BOTH SET
IN 1934.
SO FAR...THIS MONTH IS THE THIRD COLDEST EVER AT IPT...AND FOURTH
COLDEST EVER AT MDT.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...FITZGERALD
NEAR TERM...FITZGERALD
SHORT TERM...FITZGERALD
LONG TERM...FITZGERALD/STEINBUGL
AVIATION...RXR
CLIMATE...
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
517 AM EST FRI FEB 27 2015
.SYNOPSIS...
A LARGE AREA OF HIGH PRESSURE WILL BUILD ACROSS THE AREA THROUGH
THE FIRST HALF OF THE WEEKEND. A LOW PRES SYSTEM WILL LIFT OUT OF
THE MIDWEST LATE IN THE WEEKEND...PASSING OVER THE REGION SUNDAY
NIGHT. A STRONGER AREA OF LOW PRESSURE WILL LIKELY TRACK WEST OF
PENNSYLVANIA LATE TUESDAY OR EARLY WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
RADAR CONTINUES TO SHOW PATCHY LIGHT SNOW FALLING ACROSS THE
CENTRAL AND SC MTNS OF PA AT 09Z IN REGION OF LG SCALE FORCING
AHEAD OF SHORTWAVE OVR THE GRT LKS. NEAR TERM MDL DATA SUGGESTS
THE FOCUS OF THE LGT SNOW WILL REMAIN ALONG WEAK INVERTED SFC TROF
EXTENDING FROM KUNV SE TO KTHV. BLEND OF LATEST HRRR AND 4KM
NAM SUPPORT A FRESH DUSTING ACROSS THIS AREA BTWN 09Z-13Z. SATL
IMAGERY SHOWS CLEARING SKIES ACROSS WESTERN PA EARLY THIS AM...AS
DRY...ARCTIC AIR MASS OVERSPREADS THE AREA. EXPECT THIS PARTIAL
CLEARING PROGRESS INTO THE EASTERN HALF OF THE STATE LATER THIS
MORNING.
UPSTREAM OBS SUGGEST SKIES MAY BECOME MOSUNNY FOR A WHILE THIS
MORNING. HOWEVER...DIURNAL HEATING...COMBINED WITH COLD POOL
ALOFT...SHOULD YIELD A FAIR AMT OF STRATO CU THIS AFTN...ESP OVR
THE ALLEGHENY PLATEAU. GEFS MEAN 925MB TEMPS ARND -15C SHOULD
TRANSLATE TO HIGHS NO BETTER THAN ARND 10F ACROSS THE HIGHER
TERRAIN OF THE ALLEGHENIES...TO THE L/M20S ACROSS THE SUSQ VALLEY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/...
CLEARING SKIES...A CALM WIND AND SNOW COVER WILL LIKELY RESULT IN
THE LOWEST TEMPS UNTIL NEXT WINTER TONIGHT AS THE CENTER OF HIGH
PRESSURE MOVES OVER PENN.
THE IDEAL RADIATIONAL COOLING CONDS SHOULD ALLOW READINGS TO
BOTTOM OUT FROM 10-15F BELOW ZERO ACROSS THE WESTERN MTNS...TO
0-5F ABV ZERO ACROSS THE LOWER SUSQ VALLEY. THE COLDEST RURAL
VALLEYS IN NW AND NCENT PENN COULD SEE THE MERCURY SETTLE TO
AROUND -20F AT 11-12Z SATURDAY. SOME LOCATIONS ACROSS THE NW MTNS
ARE LIKELY REACH WCHILL ADVISORY CRITERIA...DESPITE A LIGHT/CALM
WIND. HOWEVER...CONFIDENCE IN WIDESPREAD APPARENT TEMPS BLW -15F
NOT THERE YET FOR AN ADVISORY.
FAIR AND STILL COLD WEATHER EXPECTED SATURDAY...AS SFC HIGH
DRIFTS OVR THE AREA. A FAST-MOVING MID LVL SHORTWAVE IS PROGGED BY
ALL MDLS TO TRACK ACROSS THE AREA LATE IN THE DAY. LOW PWAT AIR
MASS WILL PRECLUDE ANY PRECIP CONCERNS. HOWEVER...CIRRUS MAY DIM
THE SUNSHINE AT TIMES. ENS MEAN 850/925MB TEMPS REMAIN WELL BLW
NORMAL FOR THE DATE...LIKELY SUPPORTING HIGHS ONLY IN THE 20-25F
RANGE.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
A RELATIVELY MILD/ACTIVE SOUTHWEST FLOW ALOFT SHOULD PREVAIL
THROUGH THE PERIOD AS THE PERSISTENT UPPER RIDGE OVER THE WRN
U.S. TEMPORARILY BREAKS DOWN. AN ARCTIC HIGH PRESSURE SYSTEM OVER
CENTRAL PA AT THE START OF THE PERIOD WILL RETREAT INTO ATLANTIC
CANADA BY SUNDAY NIGHT. THE COMBINATION OF SHORTWAVE ENERGY IN THE
SRN STREAM EJECTING FROM A DSW TROUGH AND A DIGGING NRN STREAM
TROUGH MOVING SEWD FROM SOUTH CENTRAL CANADA TOWARD THE UPPER
MIDWEST SEEMS TO DRIVE AN EXPANDING AREA OF WAA TYPE SNOWFALL
SPREADING EASTWARD SUN-MON BEHIND THE SOUTHERLY RETURN FLOW INTO
A RETREATING COLD SECTOR ASSOCD WITH THE DEPARTING ARCTIC HIGH.
THE PCPN SHOULD BE ENHANCED ALONG AN EXPANDING BAROCLINIC ZONE
ACROSS THE CENTRAL AND EASTERN US...AS UPPER RIDGING BUILDS OVER
THE SE U.S.
WHILE THERE APPEARS TO BE LITTLE INDICATION OF A STRONG SURFACE
LOW...MODELS STILL GENERATE 0.25-0.50 INCH QPF AMTS ALONG THE
BAROCLINIC ZONE. THERMAL PROFILES SEEM TO FAVOR SNOW ACROSS THE NW
1/2 OF CENTRAL PA WITH MIXED PTYPES IN THE SOUTH/SOUTHEAST.
PRELIMINARY 24HR SNOW/ICE AMOUNTS WERE DERIVED USING A MULTI
MODEL QPF BLEND WITH PSEUDO INTERNAL BIAS CORRECTION FACTOR AND
WPC WWD. THIS RESULTS IN ADVY LEVEL SNOWFALL OVER THE NW 1/2 AND
0.10 INCH ICE/ZR OVER THE LWR SUSQ VLY. CONFIDENCE IN THE AMTS IS
AVG AT BEST GIVEN UNCERTAINTY IN QPF AND LOW-LEVEL TEMPERATURES.
THE LACK OF A DEFINED SFC CYCLONE ALSO RAISES SOME REG FLAGS.
ANOTHER COLD HP SYSTEM BUILDS INTO THE REGION MON-TUE WITH ANOTHER
SW FLOW WAA MSTR SURGE ALONG BAROCLINIC FRONTAL ZONE LKLY
IMPACTING THE AREA INTO THE MIDDLE OF NEXT WEEK. TIMING
DIFFERENCES ARE EVIDENT WITH THE GFS MORE BULLISH ON PCPN
RETURNING EARLY TUE VS. SLOWER ECMWF (TUE NGT). MIXED PTYPE ISSUES
ARE EXPECTED AGAIN WITH THIS NEXT SYSTEM.
&&
.AVIATION /09Z FRIDAY THROUGH TUESDAY/...
LARGE-SCALE FORCING AHEAD OF A SHORTWAVE OVER THE GREAT LAKES
BRINGING SOME LIGHT SNOW TO PORTIONS OF CENTRAL MTNS EARLY THIS
MORNING. THIS WILL REDUCE VSBYS/CIGS TO MVFR /OCCASIONAL IFR/
PRIMARILY OVER THE WESTERN HIGHER TERRAIN THROUGH 12Z. BRIEF
PERIOD OF MVFR CIGS POSS FURTHER EAST THROUGH 10Z.
ANOTHER PUSH OF ARCTIC AIR ARRIVES IMMEDIATELY BEHIND THE
SHORTWAVE FOR FRI. OROGRAPHIC FLOW WILL KEEP MVFR CONDITIONS IN
WESTERN HIGHER TERRAIN THROUGH MIDDAY...WITH IMPROVING CONDITIONS
IN THE AFTERNOON AS ANOMALOUSLY STRONG 1040-1045 MB SFC HIGH
PRESSURE BUILDS INTO THE COMMONWEALTH FROM THE OHIO VALLEY. VFR
WILL BE THE RULE IN CENTRAL AND EAST. WINDS WILL BE W/NW AT AROUND
10 MPH.
OUTLOOK...
FRI NIGHT AND SAT...NO SIG WX EXPECTED.
SUN...SNOW LIKELY NW MTNS. MIXED PRECIP POSSIBLE ELSEWHERE.
MON...MIXED PRECIP WITH CIG/VIS REDUCTIONS POSSIBLE...MAINLY AM.
TUE...VFR AM. MIXED PRECIP WITH CIG/VIS REDUCTIONS POSSIBLE LATE.
&&
.CLIMATE...
THE COLDEST FEBRUARY ON RECORD IS STILL LOOKING LIKELY. MONTHLY
MEAN TEMPERATURES THROUGH THE 26TH...IPT 18.2...MDT 20.7.
THE CURRENT RECORD COLDEST FEBRUARY..IPT 19.3...MDT 21.4 BOTH SET
IN 1934.
SO FAR...THIS MONTH IS THE THIRD COLDEST EVER AT IPT...AND FOURTH
COLDEST EVER AT MDT.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...FITZGERALD
NEAR TERM...FITZGERALD
SHORT TERM...FITZGERALD
LONG TERM...STEINBUGL
AVIATION...RXR
CLIMATE...
AREA FORECAST DISCUSSION...UPDATED
NWS MORRISTOWN TN
1007 AM EST FRI FEB 27 2015
.DISCUSSION...
LIGHT SNOW SHOWERS AND FLURRIES ARE PERSISTING IN SW VA AND NE TN.
THE RAP AND HRRR REFLECTIVITY DEPICTIONS ARE NOT PICKING UP ON THIS
PRECIP...BUT THE RAP AND NAM SOUNDINGS SHOW SOME SHALLOW MOISTURE
THAT EXTENDS INTO THE DENDRITE GROWTH ZONE DUE TO STEEP LAPSE
RATES. THEY SHOW THIS CONTINUING INTO THE AFTERNOON...WITH MOISTURE
DIMINISHING LATE IN THE DAY. SO WILL UPDATE TO EXTEND THE
LOW/SLIGHT CHANCE POP AND MENTION OF FLURRIES INTO THE AFTERNOON.
CLOUD COVER IS ALSO LESS THAN CURRENTLY DEPICTED IN THE GRIDS...SO
WILL ADJUST SKY COVER DOWNWARD TODAY. TEMPERATURES LOOK ON TRACK SO
FAR.
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
DGS
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
714 AM CST FRI FEB 27 2015
.DISCUSSION...
UPDATED FORECAST TO ADD A SMALL CHANCE OF LIGHT SNOW ACROSS NE AR
LATER TODAY INTO TONIGHT. LATEST GUIDANCE SUGGESTS THAT SOME OF
THE SNOW OVER THE SOUTHERN PLAINS MAY REACH NW PARTS OF THE
MIDSOUTH. 11Z HRRR INDICATES THIS POSSIBILITY AND MAV MOS POPS
ALSO HINT AT IT.
SJM
&&
PREV DISCUSSION... /ISSUED 418 AM CST FRI FEB 27 2015/
CURRENTLY...ARCTIC HIGH PRESSURE IS SETTLING ACROSS THE MID
MISSISSIPPI VALLEY. STRONG COLD AIR ADVECTION CONTINUES ACROSS THE
AREA WITH SCT-BKN LOW CLOUDS AND A FEW FLURRIES. TEMPS RANGE FROM
THE UPPER TEENS NORTH TO UPPER 20S SOUTH WITH WIND CHILLS IN THE
SINGLE DIGITS NORTH TO TEENS SOUTH.
TODAY...ARCTIC HIGH PRESSURE BEGINS TO SLIDE FROM THE MIDDLE
MISSISSIPPI VALLEY INTO THE OHIO VALLEY. A WEAK UPPER LEVEL
DISTURBANCE WILL GENERATE SOME LIGHT SNOW OVER WRN OKLAHOMA AND
THE RED RIVER VALLEY THIS AFTERNOON BUT THIS AREA IS EXPECTED TO
DISSIPATE AS IT MOVES ACROSS ARKANSAS. WOULD NOT BE SURPRISED TO
SEE A FEW FLAKES ACROSS NE ARKANSAS BUT AT THIS POINT NOT
CONFIDENT ENOUGH TO INTRODUCE INTO THE FORECAST. SHOULD SEE SOME
SUN THIS MORNING FOLLOWED BY AND INCREASE IN MIDDLE AND HIGH
CLOUDS THIS AFTERNOON. EXPECT A VERY COLD DAY WITH HIGHS IN THE
MID 20S NORTH TO MID 30S SOUTH. THE AVERAGE HIGH IN MEMPHIS IS
58F.
TONIGHT...HIGH PRESSURE REMAINS IN CONTROL. EXPECT A GOOD DEAL OF
MID AND HIGH CLOUDINESS SO TEMPS WILL NOT GET RIDICULOUSLY
COLD...JUST VERY COLD. BY MORNING LOW TEMPS WILL RANGE FROM
20-25F.
SATURDAY...ARCTIC HIGH MOVES OFF TO THE MID ATLANTIC AND SLOWLY
LOOSES ITS GRIP ON THE MIDSOUTH. SHOULD SEE AT LEAST SOME SUN WITH
TEMPS CLIMBING INTO THE UPPER 30S TO UPPER 40S. BREAK OUT THE LAWN
CHAIRS.
SATURDAY NIGHT THROUGH MONDAY...AN WEAK UPPER LEVEL DISTURBANCE
MOVING ACROSS OK/MO WILL RESULT IN A SLIGHT CHANCE OF RAIN ACROSS
THE AREA SATURDAY NIGHT...PERHAPS A LITTLE FREEZING RAIN OVER NE
AR. BY SUNDAY A MORE IMPRESSIVE MID LEVEL TROUGH MOVING THROUGH
THE GREAT LAKES WILL PUSH A COLD FRONT INTO THE MIDSOUTH WITH RAIN
CHANCES INCREASING SUNDAY INTO MONDAY. TEMPS WILL WARM INTO THE
50S MOST PLACES AHEAD OF THE FRONT ON SUNDAY. ON MONDAY TEMPS WILL
SLIGHTLY COOLER WITH HIGH PRESSURE BUILDING TO THE NORTH. PRECIP
CHANCE SHOULD TAIL OFF ACROSS THE NORTH ON MONDAY.
MONDAY NIGHT INTO WEDNESDAY...MAJOR DIFFERENCES IN TIMING BETWEEN
GFS AND ECWMF. A MAJOR UPPER LEVEL TROF WILL DEVELOP OVER THE
WESTERN U.S. EARLY IN THE WEEK AND THERE ARE DIFFERENCES BETWEEN
THE MODELS AS TO WHEN IT WILL PUSH INTO THE MIDDLE OF THE COUNTRY.
THE GFS IS MUCH FASTER...PUSHING AN ACTIVE WARM FRONT NORTH EARLY
TUESDAY WITH SURFACE LOW PRESSURE MOVING THROUGH THE MIDDLE
MISSISSIPPI VALLEY THEN A COLD FRONT WILL MOVE THROUGH TUESDAY
NIGHT. THE ECMWF PUSHES THE WARM FRONT THROUGH LATER TUESDAY AND
THE COLD FRONT THROUGH DURING THE DAY ON WEDNESDAY. AT THIS POINT
WILL TAKE THE COMPROMISE APPROACH AND SPREAD FAIRLY HIGH POPS
THROUGH THE PERIOD. AHEAD OF THE COLD FRONT SURFACE DEWPOINTS
CLIMB INTO THE 60S AND THERE ARE INDICATIONS THAT SOME INSTABILITY
WILL BE PRESENT SO WILL NEED TO WATCH THE TUESDAY NIGHT-WEDNESDAY
PERIOD FOR SEVERE POTENTIAL. EXPECT HIGHS IN THE 60S AND SOME 70S
TUESDAY. HIGHS ON WEDNESDAY WILL BE HIGHLY DEPENDENT ON WHETHER
THE FRONT HAS GONE THROUGH.
WEDNESDAY NIGHT THROUGH THURSDAY...PRECIP WRAPPING UP AND MUCH
COLDER. THE GFS HAS A MUCH COLDER BLAST BEHIND THIS SYSTEM BUT
WILL TEMPER THAT GIVEN THE ECMWF SOLUTION. NONETHELESS BELOW
NORMAL TEMPS EXPECTED ONCE AGAIN FOR THE END OF THE WEEK.
SJM
&&
.AVIATION...
12Z TAF CYCLE
MVFR CIGS WILL LINGER THIS MORNING AT TUP...OTHERWISE THE
TAF SITES WILL BE VFR THROUGH THE PERIOD. NORTH TO NORTHEAST
WINDS IN THE 10-15 KT RANGE WILL DIMINISH TO 6-9 KTS LATE.
JAB
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS RENO NV
911 AM PST FRI FEB 27 2015
.UPDATE...
MAIN FOCUS FOR THE UPDATE IS TO ISSUE A WINTER WEATHER ADVISORY
FOR THE SIERRA FRONT TONIGHT INTO SATURDAY. AS FOR THE REST OF
TODAY, DID MAKE SOME MINOR CHANGES TO ADD THE THREAT OF
THUNDERSTORMS NORTH OF I-80 THIS AFTERNOON AND REDUCE SOME CLOUD
COVER TO MAKE IT MORE MOSTLY CLOUDY AS THERE WILL BE BREAKS OF
SUN. REGARDING THE CONVECTION, MODERATE SHOWERS ARE ALREADY
POPPING NORTH OF HIGHWAY 50 AND THESE SHOULD INTENSIFY WITH
HEATING. MODELS ALL SHOWING ENOUGH INSTABILITY FOR SOME ISOLATED
THUNDERSTORMS AS WELL.
TONIGHT INTO SATURDAY MORNING, THE GFS AND EC CONTINUE TO SHOW A
BAND OF MODERATE SNOW TO AFFECT PORTIONS OF THE TAHOE BASIN AND
SIERRA FRONT. HIGH CONFIDENCE NOW IN THIS BAND DEVELOPING AS THE
LATEST HRRR IS SHOWING IT AT THE END OF ITS RUN. LATEST RUNS HAVE
ALSO SHIFTED IT SOUTH AGAIN OVER DOUGLAS COUNTY AND SOUTH LAKE.
ADVISORY ALREADY ISSUED FOR TAHOE AND WILL ADD THE SIERRA FRONT TO
RUN FROM 8 PM TONIGHT UNTIL 10 AM TOMORROW MORNING. OUTSIDE OF
THIS BAND LIGHTER AMOUNTS NEAR 2 INCHES FOR THE SIERRA FRONT AND
UP TO 4 INCHES FOR THE TAHOE BASIN ARE LIKELY. HOWEVER, IN THIS
BAND EXPECT HEAVIER AMOUNTS AS MODEL QPF IS NEAR 1/2 TO 3/4 INCH
IN PLACES. WITH A GOOD DENTRITIC SNOW GROWTH LAYER PRESENT, IT
COULD ADD UP. WILL GO WITH 3-6 INCHES IN THIS BAND FOR THE SIERRA
FRONT AND 4-8 FOR THE TAHOE BASIN WITH 12+ INCHES POSSIBLE ABOVE
7K.
WILL MENTION THE MOST LIKELY PLACES (OR OUR BEST GUESS) FOR
THE HEAVIER BAND. HOWEVER, THE EXACT LOCATION REMAINS LOW
CONFIDENCE. IT IS STILL POSSIBLE IT COULD BE CENTERED OVER CARSON
CITY OR EVEN TRUCKEE/RENO (LOWEST PROBABILITY FOR THE LATTER).
HOPE TO HAVE ALL UPDATES OUT BY 10 AM. WALLMANN
&&
.PREVIOUS DISCUSSION... /ISSUED 324 AM PST FRI FEB 27 2015/
SYNOPSIS...
WINTER SYSTEM IS ON TRACK TO IMPACT THE SIERRA AND NORTHWEST
NEVADA TODAY AND SATURDAY. ACCUMULATING SNOW AND DIFFICULT TRAVEL
CONDITIONS ARE LIKELY IN THE SIERRA WITH LIGHTER ACCUMULATIONS
POSSIBLE IN WESTERN NEVADA. THIS SYSTEM WILL SLOWLY EXIT SUNDAY
WITH ANOTHER CHANCE AT PRECIPITATION POSSIBLE LATE MONDAY INTO
TUESDAY.
SHORT TERM...
THE UPPER LEVEL LOW RESPONSIBLE FOR THE THE WINTER WEATHER THIS
WEEKEND IS CURRENTLY DROPPING SOUTH ALONG THE PACIFIC NORTHWEST
COAST. AHEAD OF THIS FEATURE, WEAK WARM AIR ADVECTION IS GENERATING
LIGHT PRECIPITATION EARLY THIS MORNING.
THE LOW WILL CONTINUE SOUTH TODAY, PUSHING A DIFFUSE COLD FRONT
THROUGH THE EASTERN SIERRA AND WESTERN NEVADA AND BRINGING GUSTY
WEST TO NORTHWEST WINDS TO THE REGION THIS AFTERNOON. THE FRONT
WILL RAPIDLY DROP SNOW LEVELS TO AROUND 4000-5000 FEET FRIDAY
NIGHT, POSSIBLY REACHING AS LOW AS 3500 FEET BY SATURDAY MORNING.
MOST OF THE MOISTURE IS ALONG AND BEHIND THE FRONT WITH SHOWERS
EXPECTED TO INCREASE IN COVERAGE THIS AFTERNOON AND EVENING.
SHOWER ACTIVITY IS RATHER DISORGANIZED, OUTSIDE OF A DEFORMATION
BAND EXPECTED TO FORM LATE TONIGHT INTO SATURDAY. THESE BANDS ARE
NOTORIOUSLY HARD TO PINPOINT LOCATIONS, BUT MODEL TRENDS OVER THE
PAST COUPLE DAYS ARE SHOWING THIS BAND DEVELOPING BETWEEN THE I-80
AND HIGHWAY 50 CORRIDOR. CONFIDENCE IS HIGH THAT THERE WILL BE
SNOW SHOWERS BOTH IN THE SIERRA AND WESTERN NEVADA, BUT MUCH
LOWER IN THE TOTALS. THE SHOWERY NATURE OF THIS SYSTEM MEANS THAT
SNOW TOTALS WILL BE HIGHLY VARIABLE.
THE GREATEST CONFIDENCE IN ACCUMULATING SNOWS IS THROUGH THE TAHOE
BASIN WHERE A WINTER WEATHER ADVISORY IS IN EFFECT LATE FRIDAY
AFTERNOON THROUGH SATURDAY AFTERNOON. 6 TO 12 INCHES OF SNOW IS
POSSIBLE ALONG THE CREST, WITH 3 TO 7 INCHES AT LAKE LEVEL. THOSE
LOCATIONS UNDER ANY ORGANIZED BANDS WILL BE ON THE HIGHER END OF
THE TOTALS, WHILE LOCATIONS WITH JUST GENERAL SHOWERS WILL BE ON
THE LOWER END. FOR WESTERN NEVADA AND THE SIERRA FRONT, CONFIDENCE
IS INCREASING IN SOME AREAS SEEING SEVERAL INCHES OF ACCUMULATION,
BUT CONFIDENCE REMAINS LOW IN EXACTLY WHERE...AND SOME AREAS MAY
STILL SEE NOTHING. MONO COUNTY IS LIKELY TO SEE ACCUMULATING SNOWS
SATURDAY AFTERNOON INTO SUNDAY AS THE UPPER LEVEL FLOW TURNS
NORTHEAST, AIDING IN UPSLOPE ENHANCEMENT. CURRENT FORECAST WOULD
YIELD 6 TO 10 INCHES OF SNOW IN THE HIGH SIERRA WITH 2 TO 4 INCHES
IN THE REST OF MONO COUNTY. THE BIGGEST THING TO TAKE AWAY IS THAT
TRAVEL WILL LIKELY BE IMPACTED FRIDAY AFTERNOON THROUGH SUNDAY
THROUGH PORTIONS OF THE SIERRA AND WESTERN NEVADA. BE PREPARED FOR
WINTER DRIVING CONDITIONS AND CHECK BOTH WEATHER AND ROAD CONDITIONS
BEFORE TRAVEL.
THERE IS PLENTY OF INSTABILITY WITHIN THE CORE OF THE LOW AND THERE
IS A SLIGHT CHANCE OF THUNDERSTORMS NORTH OF I-80 LATE THIS AFTERNOON
AND THEN FROM I-80 SOUTH SATURDAY. PELLET SHOWERS AND/OR A WINTRY
MIX IS POSSIBLE THROUGH THE DAY SATURDAY IN THE COLD CORE. THE LOW
IS SLOWER TO EXIT THE AREA THAN PREVIOUSLY PROGGED, WITH SHOWERS
POSSIBLY LINGERING IN MONO COUNTY THROUGH SUNDAY AFTERNOON IN THE
MOIST AND UNSTABLE NORTHEAST FLOW. TEMPERATURES WILL BE BELOW
NORMAL THROUGH THE PERIOD WITH THE BREEZY WINDS MAKING IT FEEL
EVEN COLDER. DJ
LONG TERM...MONDAY THROUGH THURSDAY...
NO MAJOR CHANGES TO THE LONG TERM FORECAST, WITH THE MAIN WEATHER
CONSIDERATION MONDAY INTO TUESDAY ANY ADDITIONAL SLIDER ENERGY (AND
ASSOCIATED SNOW SHOWERS) THAT MIGHT MOVE OVER EASTERN CALIFORNIA AND
WESTERN NEVADA BEHIND THIS WEEKEND`S SYSTEM.
MONDAY AND MONDAY NIGHT, THE ECMWF, GFS AND GEM ENSEMBLES STILL SHOW
VARYING SOLUTIONS REGARDING A SLIDER-TYPE DISTURBANCE TO MOVE
OVER/NEAR THE REGION. IN FACT, IN THE LAST FEW OPERATIONAL RUNS THE
GFS AND ECMWF HAVE GONE THE OPPOSITE WAY WITH THE GFS LEANING
FARTHER EAST AND MORE PROGRESSIVE WITH THE ECMWF GETTING SLOWER AND
FARTHER WEST (OVER NORTHERN CALIFORNIA) WITH THE SLIDER. MEANWHILE,
THE GEM SEEMS TO BE IN BETWEEN WITH MANY ENSEMBLE RUNS SHOWING THE
DISTURBANCE OVER WESTERN NEVADA OR FAR EASTERN CALIFORNIA.
THE POSITION OF THE SLIDER IS KEY FOR THE COVERAGE/INTENSITY OF SNOW
SHOWERS FOR THE SIERRA AND WESTERN NEVADA, WITH A TRACK NEAR OR WEST
OF THE CREST (BUT STILL EAST OF I-5) IDEAL FOR AN ORGANIZED BAND OF
SNOW. WITH LARGE UNCERTAINTY AS TO THE EXACT TRACK OF THE DISTURBANCE
MONDAY-TUESDAY, I HAVE KEPT THE RUNNING SLIGHT CHANCE TO CHANCE OF
SHOWERS IN PLACE. IN ANY CASE, WELL BELOW AVERAGE TEMPERATURES ARE ON
TAP FOR MONDAY AND TUESDAY WITH NORTHERLY FLOW KEEPING COLDER AIR
INTACT.
WEDNESDAY AND THURSDAY STILL LOOK DRY AS ENSEMBLES ARE IN GOOD
AGREEMENT WITH BUILDING A RIDGE OVERHEAD. TEMPERATURES WILL BEGIN TO
REBOUND TOWARDS NORMAL FOR THE SECOND HALF OF THE WEEK. SNYDER
AVIATION...
FOR THIS MORNING IN NORTHEAST CALIFORNIA AND WESTERN NEVADA,
SCATTERED SHOWERS WILL BRING OCCASIONAL MVFR CIGS TO THE NORTHERN
SIERRA WITH OCCASIONAL HIGHER TERRAIN OBSCUREMENT TO WESTERN NEVADA
NORTH OF HIGHWAY 50. NORTH OF KSVE-GERLACH, CIGS LOOK WORSE WITH
WIDESPREAD MVFR CIGS WITH -SHSN ABV 5-5.5 KFT MSL (AND -SHRASN BLO).
THIS AFTERNOON AND TONIGHT, CIGS/VIS WORSEN AS LOW PRESSURE DROPS
INTO NORTHERN CALIFORNIA AND NEVADA AND WIDESPREAD SNOW AND
RAIN/SNOW BELOW 5,000 FT MSL DEVELOPS. WIDESPREAD IFR CIGS AND ICING
ARE EXPECTED IN THE SIERRA, WITH MVFR (LOCALLY IFR) CIGS INTO
WESTERN NEVADA NORTH OF HIGHWAY 50. ACCUMULATING SNOW IS LIKELY FOR
KTRK/KTVL WITH EVEN SOME ACCUMULATIONS POSSIBLE AT KRNO/KCXP (60%
CHANCE) BETWEEN LATE FRIDAY EVENING AND SATURDAY MORNING.
FOR KMMH, THE WORSE CONDITIONS ARE LIKELY TO BE ON SATURDAY. SNYDER
&&
.REV WATCHES/WARNINGS/ADVISORIES...
NV...WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO 4 PM PST
SATURDAY NVZ002.
WINTER WEATHER ADVISORY FROM 8 PM THIS EVENING TO 10 AM PST
SATURDAY NVZ003.
CA...WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO 4 PM PST
SATURDAY CAZ072.
&&
$$
FOR MORE INFORMATION FROM THE NATIONAL WEATHER SERVICE VISIT...
HTTP://WEATHER.GOV/RENO (ALL LOWER CASE)
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
1242 PM EST FRI FEB 27 2015
.SYNOPSIS...
WEAK IMPULSE MOVES THROUGH THE AREA TODAY FOLLOWED BY AN EXTENSIVE
HIGH PRESSURE SYSTEM FOR A MAJORITY OF THE WEEKEND. AS THE HIGH
SLIPS OFF THE COAST ON SUNDAY A WEAK WARM FRONT LIFTS THROUGH THE
REGION AS LOW PRESSURE PASSES TO OUR WEST AND ITS ASSOCIATED COLD
FRONT PUSHES THROUGH ON MONDAY. ANOTHER LOW PRESSURE EJECTS OUT OF
THE CENTRAL PLAINS AND CROSSES OUR REGION ON TUESDAY INTO WEDNESDAY.
THE LOWS ASSOCIATED COLD FRONT PUSHES THROUGH LATER ON WEDNESDAY
WITH ANOTHER EXPANSIVE HIGH PRESSURE SYSTEM FILLING IN BEHIND IT.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
CLOUDS HAVE CONTINUED TO BREAK UP IN MOST PLACES THIS AFTERNOON.
SO WILL FEATURE A MOSTLY SUNNY AFTERNOON ACROSS THE REGION. THE
LATEST RAP AND HRRR MODEL RUNS DO NOT FORM ANY SNOW FLURRIES
EITHER ACROSS THE REGION. INCREASED TEMPERATURES A DEGREE OR TWO WARMER
WITH THE 12:30 PM UPDATE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SATURDAY/...
AT LEAST ONE MODEL IS DEPICTING LOW LEVEL CLOUDS DEVELOPING BY THIS
EVENING. HOWEVER, THIS SEEMS UNLIKELY WITH THE SYNOPTIC PATTERN OF A
SURFACE HIGH SLIDING EAST TOWARD THE REGION AS FLOW ALOFT
TRANSITIONS TO MORE ZONAL FLOW. THEREFORE, EXPECT CLEARING SKIES
THIS EVENING INTO THE OVERNIGHT HOURS. THIS, COMBINED WITH
SUBSIDENCE IN THE LOW LEVELS AND LIGHT WINDS WILL LEAD TO PRIME
RADIATIONAL COOLING CONDITIONS, ESPECIALLY FOR LOCATIONS THAT STILL
HAVE A SNOW PACK. THUS, WENT SLIGHTLY BELOW GUIDANCE FOR LOWS.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
MEDIUM RANGE GUIDANCE IS IN PRETTY DECENT AGREEMENT WITH THE LARGE
SCALE FEATURES THROUGH THE EXTENDED PERIOD. THE MID-LEVELS TAKE ON
MORE OF A ZONAL-ISH FLOW OVER THE WEEKEND WITH THE NEXT EMBEDDED
WAVE EXPECTED BY MONDAY FOLLOWED BY DEEPENING RIDGING THROUGH MID-
WEEK AS THE LONGWAVE TROUGH RELOADS TO OUR WEST AND ADVANCES THROUGH
LATE IN THE PERIOD.
SATURDAY...HIGH PRESSURE WILL BE OVERHEAD ALLOWING FOR LOTS OF
SUBSIDENCE AND MOSTLY CLEAR SKIES. TEMPERATURES WILL BE RATHER COLD
STILL, NEARLY 20 DEGREES UNDER CLIMO FOR THE LAST DAY OF
METEOROLOGICAL WINTER.
SUNDAY - MONDAY...ZONAL-ISH FLOW TURNS A BIT SHARPER AS THE BROAD
TROUGH RELOADS WELL TO OUR WEST. ANOTHER PASSING SHORTWAVE ALOFT
APPROACHES AND PUSHES A COLD FRONT THROUGH THE REGION VERY LATE
SUNDAY INTO MONDAY MORNING. OUT AHEAD OF THE FRONT TEMPERATURES ARE
ABLE TO MODIFY A BIT THANKS TO THE DEPARTING HIGH PRESSURE NOW OFF
THE COAST AND A LIGHT RETURN FLOW SETTING UP. WE CONFINED THE HIGHER
POPS UNTIL LATE SUNDAY NIGHT JUST AHEAD AND WITH THE FRONTAL
PASSAGE. DECENT AMOUNT OF THETA-E ADVECTION OCCURRING AHEAD OF THE
COLD FRONT WITH ENOUGH LIFT FOR A LIGHT SNOW TO START BEFORE A
WINTRY MIX OF RAIN/SNOW/SLEET/FREEZING RAIN OCCURS, MOSTLY ACROSS
THE SOUTHERN HALF OF THE CWA, BY MONDAY MORNING. THERE COULD BE SOME
WAK COLD AIR DAMMING OCCURRING, EVEN AS WINDS TURN MORE EASTERLY,
BUT GIVEN THE ARCTIC HIGH WILL BE OFFSHORE AND NOT EXPECTING A HUGE
RESPONSE IN THE LOW-LEVEL WINDS THE GROUND COULD STILL BE COLD
ENOUGH FOR SOME LIGHT FREEZING RAIN...MORE SO THEN WE ARE
CURRENTLY CARRYING IN THE FORECAST.
THE BEST CHANCES FOR AN ALL SNOW EVENT REMAINS ACROSS OUR
NORTHERN MOST ZONES WHERE THE WARM NOSE GETS CLOSE BUT DOES NOT
HAVE ENOUGH PUSH TO MOVE THROUGH, PRIOR TO THE COLD FRONT USHERING
IN ANOTHER SHOT OF COLDER AIR. WE ARE CURRENTLY CARRYING A FEW
INCHES OF SNOW ACROSS THE POCONOS AT THIS TIME.
TUESDAY - THURSDAY...WITH THE COLD FRONT TO OUR EAST AND A BRIEF
SHOT OF HIGH PRESSURE BEHIND IT, THE NEXT SYSTEM, FORMING DEEP IN
THE SOUTH, BEGINS TO ENTER THE REGION FROM THE SOUTHWEST LATER ON
TUESDAY. A LIGHT ONSHORE FLOW WILL HELP TO ENHANCE THE LOW-LEVEL
MOISTURE FLUX WHEN COMBINED WITH A STRONG LOW-LEVEL SOUTHERLY SURGE
OF WARM/MOIST AIR. THIS EVENT COULD HAVE A COPIOUS AMOUNT OF
MOISTURE WITH IT, GIVEN ITS ORIGIN AND THE MODIFYING AIRMASS WE`LL
HAVE IN PLACE. TOO EARLY FOR PTYPE SPECIFICS BUT IT DOES APPEAR TO
BE ANOTHER MIXED EVENT. THIS SYSTEMS COLD FRONT DRAGS THROUGH RATHER
SLOWLY, AS THE TROUGHING TO OUR WEST SHARPENS AND SLOWS IT DOWN A
BIT. THIS COULD ALLOW FOR A LONGER DURATION EVENT SO WE CARRY CHANCE
POPS THROUGH THE FIRST HALF OF THURSDAY BEFORE DRYING OUT.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE,
KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS.
VFR CONDITIONS THROUGH THE TAF PERIOD. SOME SCATTERED CLOUDS THIS
AFTERNOON AROUND 5,000 FEET SHOULD CLEAR OUT THIS EVENING BEFORE
CIRRUS ABOVE 10,000 FEET MOVES IN OVERNIGHT. NORTHWESTERY WINDS
FROM 320-350 DEGREES AS WELL, TOP WINDS AROUND 10 KNOTS THIS
AFTERNOON. WIND COULD SHIFT MORE WESTERLY WITH SLIGHTLY LOWERING
CIRRUS IN THE AFTERNOON ON SATURDAY.
OUTLOOK...
SATURDAY NIGHT - SUNDAY MORNING...VFR. NORTHERLY WINDS PREVAIL AS
HIGH PRESSURE NOSES IN FROM THE WEST.
SUNDAY NIGHT - MONDAY...MVFR/IFR EXPECTED WITH SNOW TO
RAIN/FREEZING RAIN POSSIBLE BY EARLY MONDAY MORNING.
TUESDAY...VFR.
&&
.MARINE...
WITH THE MORNING UPDATE WE DID RAISE WAVE HEIGHTS BASED ON BUOY
OBS TO BETWEEN FIVE AND SIX FEET. THIS LEADS TO A HIGHER
CONFIDENCE SCA SEAS WILL PERSIST THROUGH THE LATE AFTERNOON. WINDS
HAVE ALREADY SUBSIDED AND SHOULD REMAIN BELOW SCA CRITERIA TODAY
AND TONIGHT, ALTHOUGH A FEW GUSTS NEAR 20 KT ARE POSSIBLE OVER THE
OCEAN WATERS THIS EVENING. WAVE HEIGHTS SHOULD START TO DECREASE
TONIGHT.
OUTLOOK...
SATURDAY - SUNDAY...SUB-SCA EXPECTED, THOUGH PERSISTENT
NORTHEAST WINDS MAY ALLOW FOR BUILDING SEAS ACROSS OUR SOUTHERN
ZONES.
SUNDAY NIGHT - MONDAY...POSSIBLE SCA CONDITIONS LATE ON SUNDAY
AHEAD OF AN APPROACHING COLD FRONT WITH INCREASING SOUTHERLY
WINDS AND BUILDING SEAS EXPECTED. BETTER CHANCE BEHIND COLD FRONT
PASSAGE ON MONDAY WITH GUSTY WEST WINDS.
TUESDAY...SUB-SCA EXPECTED.
&&
.CLIMATE...
RECORDS FOR FRIDAY AND SATURDAY. NOTE RECORDS FOR FRIDAY UNLIKELY
BUT POSTED JUST IN CASE ONE OR 2 ARE APPROACHED AT 1159 PM FRIDAY
EVENING.
THERE IS A GREATER CHANCE OF RECORDS SATURDAY.
POR / SITE / FEB 27 FEB 28
1872 / KPHL / 6 1900 9 1934
1874 / KACY / 7 1934* 2 1934
1894 / KILG / 5 1934 -5 1934
1922 / KABE / -2 1963 -10 1934
1869 / KRDG / 4 1934* 3 1934
1865 / KTTN / 6 1934 1 1934
1948 / KGED / 10 1963 8 1950
1901 / KMPO / -9 1993 -15 1907
KACY RER FOR 3/1 IS 5 IN 1980.
NOTE: * INDICATE AND OTHER YEARS.
NOTE: POR = PERIOD OF RECORD,THE YEAR OFFICIAL CLIMATE OBS BEGAN.
THE FOLLOWING IS A TABLE OF THE ***PROJECTED*** TOP 5 COLDEST
FEBRUARY`S ON RECORD, BASED ON THE CURRENT FORECAST, AND THUS
SUBJECT TO CHANGE. EACH RANKING DENOTES THE MEAN FEBRUARY
TEMPERATURE /F/ AND YEAR OF OCCURRENCE.
WE REREVIEWED THESE PROJECTIONS LISTED BELOW USING THIS THURSDAY
MORNINGS (26TH) MINS AND THE PHI FCST AS SEEN ON NDFD AND SFT`S. WE
SEE PHL/ABE/ILG ALL VERY CLOSE TO YESTERDAYS PROJECTIONS. KACY
CHANGED TO A WARMER PROJECTION HOWEVER THAT COULD YET REVERT BACK TO
A COLDER MONTHLY AVERAGE DUE TO THE POTENTIAL FOR RADIATIONAL
COOLING ON ONE OR 2 OF THE MORNINGS.
POR / SITE / 1ST RANK / 2ND RANK / 3RD RANK / 4TH RANK / 5TH RANK
1872 / KPHL / 22.2(1934) 23.0(1979) 24.3(1885) 24.6(1978) 25.5(2015)
1874 / KACY / 21.6(1979) 23.8(1978/1934) 24.5(2015) 25.5(1875) 25.7
(1905)
1894 / KILG / 20.2(1934) 22.1(1979) 22.7(1978) 24.5(2015) 24.9(1936)
1922 / KABE / 16.6(1934) 18.9(2015) 20.4(1979) 21.6(1936) 22.0(1963)
PER THE ABOVE TABLE, ABE IS EASILY ON TRACK FOR THE SECOND COLDEST
FEBRUARY, ATLANTIC CITY 3RD COLDEST FOLLOWED BY THE FOURTH COLDEST
AT ILG, AND THE FIFTH COLDEST AT PHL.
THE FOLLOWING IS A TABLE OF THE ***PROJECTED*** MEAN FEBRUARY 2015
TEMPERATURES /F/ AND DEPARTURES FROM NORMAL. THIS IS ALSO BASED ON
THE CURRENT FORECAST, AND THUS SUBJECT TO CHANGE. JANUARY 2015 MEAN
TEMPERATURES ARE ALSO INCLUDED FOR COMPARISON PURPOSES.
POR / SITE / FEB MEAN(F) / FEB NORMAL(F) / DEPARTURE / JAN MEAN(F)
1872 / KPHL / 25.5 / 35.7 / -10.2 / 30.9
1874 / KACY / 24.5 / 35.3 / -10.8 / 30.2
1894 / KILG / 24.5 / 35.1 / -10.6 / 30.3
1922 / KABE / 18.9 / 30.7 / -11.8 / 25.9
IN GENERAL, MEAN TEMPERATURES AT OUR FOUR MAJOR CLIMATE SITES ARE ON
TRACK TO BE AROUND 10 TO 12 DEGREES BELOW NORMAL FOR FEBRUARY 2015.
IT`S ALSO INTERESTING TO NOTE THAT THE PROJECTED FEBRUARY 2015 MEAN
TEMPERATURES WILL BE WELL BELOW THE JANUARY 2015 MEAN TEMPERATURES.
TO PUT THIS IN PERSPECTIVE, NORMAL MEAN FEBRUARY TEMPERATURES AT OUR
FOUR MAJOR CLIMATE SITES ARE ABOUT 2 TO 3 DEGREES WARMER THAN JANUARY.
THE OPPOSITE IS SHAPING UP FOR FEBRUARY 2015.
ALSO...OF INTEREST...THIS WOULD ALSO BE THE SECOND COLDEST MONTHLY
MEAN TEMPERATURE ON RECORD AT ALLENTOWN SINCE RECORDS BEGAN IN
1922; FEBRUARY 1934 BEING THE COLDEST!
PHL PROJECTS AROUND 12TH COLDEST MONTHLY MEAN SINCE RECORDS BEGAN IN
1873.
ATLANTIC CITY 7TH COLDEST MONTHLY MEAN SINCE RECORDS BEGAN THERE
IN 1874.
WILMINGTON HAS MISSING DATA IN ITS DATABASE (1897-1916) AND SO WE
DON`T FOCUS AS MUCH ATTENTION ON THAT RECORD.
&&
EQUIPMENT: TEMPERATURE AT GED MAY BE RUNNING SEVERAL DEGREES TO
WARM, TECHS ARE WORKING ON ISSUE. NOT USED IN 12:30 PM UPDATE.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 4 PM EST THIS
AFTERNOON FOR ANZ450>455.
&&
$$
SYNOPSIS...HEAVENER/O`HARA
NEAR TERM...GAINES
SHORT TERM...DRAG/JOHNSON
LONG TERM...HEAVENER
AVIATION...GAINES
MARINE...GAINES/HEAVENER/JOHNSON
CLIMATE...STAFF
EQUIPMENT... GAINES
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
309 PM EST FRI FEB 27 2015
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 303 AM EST FRI FEB 27 2015
HIGH PRESSURE IS EXPECTED ACROSS THE AREA THROUGH SATURDAY. A
FRONTAL SYSTEM IS EXPECTED TO MOVES THROUGH THE AREA FRONT SATURDAY
NIGHT INTO SUNDAY NIGHT. A STRONGER LOW PRESSURE SYSTEM MAY AFFECT
THE AREA TOWARDS THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 1025 AM EST FRI FEB 27 2015
CANCELLED WIND CHILL ADVISORY AS WIND CHILLS ARE NO LONGER REACHING
ADVISORY CRITERIA.
OTHERWISE...SATELLITE INDICATES MOSTLY CLEAR SKIES WERE ACROSS MOST
OF THE AREA. RUC MODEL SOUNDINGS INDICATE CU MAY INCREASE THIS
AFTERNOON CAUSING SKIES TO BECOME PARTLY CLOUDY.
RUC SOUNDINGS INDICATE HIGHS FROM MIDDLE TEENS NORTH TO AROUND 20
SOUTH WHICH IS CLOSE TO CURRENT FORECAST AND A LITTLE WARMER THAN
MOST MOS GUIDANCE. THIS SEEMS REASONABLE. THERE SHOULD BE A LOT OF
SUNSHINE AT LEAST THROUGH MID DAY AND THEN A LITTLE MORE CLOUDINESS
THIS AFTERNOON. REST OF NEAR TERM SEEMS TO BE ON TRACK.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
ISSUED AT 303 AM EST FRI FEB 27 2015
DRY CONDITIONS EXPECTED TONIGHT AND SATURDAY AS SURFACE HIGH
PRESSURE GRADUALLY SHIFTS OFF TO THE EAST. MAIN ITEM OF INTEREST
DURING THIS PERIOD IS A SHORT WAVE TROUGH THAT IS EXPECTED TO DROP
SOUTHEAST ACROSS THE GREAT LAKES SUNDAY NIGHT. THE SURFACE
REFLECTION ASSOCIATED WITH THIS FEATURE DOESN/T LOOK TOO
IMPRESSIVE...BUT MODELS SUGGEST A 40 KT LOW LEVEL JET ASSOCIATED
WITH THIS FEATURE...WHICH SHOULD PROVIDE QUITE A BIT OF LIFT.
WILL BRING IN HIGH POPS BY LATE SATURDAY NIGHT AND SUNDAY BASED ON
ABOVE REASONING...WITH POPS TAPERING OFF SUNDAY NIGHT AS MAIN LIFT
PUSHES OFF TO THE EAST. OPERATIONAL MODELS SUGGEST MAINLY SNOW OVER
ABOUT THE NORTHERN HALF OF THE FORECAST AREA...WITH MORE OF A MIX
OVER THE SOUTHERN HALF...WHICH GOES ALONG WITH THE PREVIOUS
FORECAST. HOWEVER...THE ENSEMBLES SUGGEST A STRONGER PUSH OF WARM
AIR IS POSSIBLE...WITH POTENTIAL FOR RAIN AS FAR NORTH AS THE
NORTHERN ZONES BY SUNDAY. CAN/T RULE OUT THESE SOLUTIONS GIVEN THE
STRENGTH OF THE LOW LEVEL JET. FOR NOW...WILL STICK WITH THE
PREVIOUS FORECAST REGARDING PRECIPITATION TYPES AND MONITOR THE
TRENDS. SEVERAL INCHES OF SNOW ARE POSSIBLE WITH THIS
SYSTEM...ESPECIALLY OVER THE NORTHERN ZONES.
BASED ON LOW LEVEL THICKNESSES...THE GFS MOS TEMPERATURE GUIDANCE
FOR TONIGHT AND SATURDAY LOOK A LITTLE COLD. WILL BUMP UP THE
GUIDANCE A FEW DEGREES IN THOSE PERIODS. THE GUIDANCE HIGHS ON
SUNDAY LOOK TOO WARM CONSIDERING EXPECTED PRECIPITATION...SO WILL
NUDGE THOSE NUMBERS DOWN ABOUT A CATEGORY.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
ISSUED AT 230 PM EST FRI FEB 27 2015
MODELS ARE CLOSE ENOUGH THAT THE SUPERBLEND INITIALIZATION WAS
ACCEPTED FOR MOST ITEMS.
SOUTHWEST FLOW ALOFT IN THE FIRST PART OF THE LONG TERM WILL ALLOW
NEAR TO ABOVE AVERAGE TEMPERATURES AS AN AREA OF LOW PRESSURE MOVES
TO THE NORTH OF CENTRAL INDIANA. HOWEVER AN UPPER TROUGH WILL MOVE
INTO THE AREA FOR THE END OF THE PERIOD ALLOWING WELL BELOW NORMAL
TEMPERATURES ONCE AGAIN.
LOOKS LIKE PRECIPITATION WILL MAINLY ARRIVE OVERNIGHT MONDAY NIGHT
INTO EARLY TUESDAY. MODELS STILL ARE BRINGING IN WARM AIR ALOFT
QUICKLY...SO MIXED PRECIPITATION TO FREEZING RAIN LOOKS TO BE THE
PRECIPITATION TYPE MONDAY NIGHT.
SURFACE TEMPERATURES STILL LOOK TO BE COLD TUESDAY MORNING SO KEPT
THE FREEZING RAIN MENTION THEN. AS WARM AIR AT THE SURFACE FINALLY
ARRIVES RAIN WILL FALL LATER TUESDAY MORNING THROUGH THE REMAINDER
OF THE DAY. COULD BE ENOUGH RAIN TO CAUSE SOME FLOODING ISSUES GIVEN
THE FROZEN GROUND. WILL CONTINUE TO MONITOR CLOSELY.
MODELS DIFFER IN SPEED OF COLD AIR RETURNING TUESDAY NIGHT BUT STILL
FEEL IT A MIX OF RAIN AND SNOW IS WARRANTED AS PRECIPITATION TYPE
MOST AREAS. AS A WAVE RIDES ALONG THE FRONT ON WEDNESDAY
PRECIPITATION CHANCES WILL CONTINUE...WITH CHANCES FOR SNOW
NORTHWEST AND RAIN/SNOW SOUTHEAST.
THURSDAY AND FRIDAY LOOK TO BE DRY AND COLD WITH HIGH PRESSURE
MOVING IN.
&&
.AVIATION /DISCUSSION FOR THE 27/2100Z TAF UPDATE/...
ISSUED AT 307 PM EST FRI FEB 27 2015
UPDATE...
NO CHANGES.
PREVIOUS DISCUSSION...
VFR EXPECTED THROUGH THE PERIOD WITH WINDS GENERALLY LESS THAN 10KT.
SCATTERED /TO PERHAPS BRIEFLY BROKEN AT KIND/KBMG/ CU FIELD WILL
DISSIPATE WITH LOSS OF HEATING NEAR SUNSET. OTHERWISE MID AND HIGH
CLOUDS WILL INCREASE TONIGHT AND SATURDAY AHEAD OF NEXT SYSTEM.
WINDS WILL BECOME LIGHT THIS EVENING AND THEN SOUTHEAST AT LESS THAN
10KT SATURDAY.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...JAS
NEAR TERM...JH
SHORT TERM...JAS
LONG TERM....50
AVIATION...50/TDUD
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSINDIANAPOLIS
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
230 PM EST FRI FEB 27 2015
.UPDATE...
THE LONG TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 303 AM EST FRI FEB 27 2015
HIGH PRESSURE IS EXPECTED ACROSS THE AREA THROUGH SATURDAY. A
FRONTAL SYSTEM IS EXPECTED TO MOVES THROUGH THE AREA FRONT SATURDAY
NIGHT INTO SUNDAY NIGHT. A STRONGER LOW PRESSURE SYSTEM MAY AFFECT
THE AREA TOWARDS THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 1025 AM EST FRI FEB 27 2015
CANCELLED WIND CHILL ADVISORY AS WIND CHILLS ARE NO LONGER REACHING
ADVISORY CRITERIA.
OTHERWISE...SATELLITE INDICATES MOSTLY CLEAR SKIES WERE ACROSS MOST
OF THE AREA. RUC MODEL SOUNDINGS INDICATE CU MAY INCREASE THIS
AFTERNOON CAUSING SKIES TO BECOME PARTLY CLOUDY.
RUC SOUNDINGS INDICATE HIGHS FROM MIDDLE TEENS NORTH TO AROUND 20
SOUTH WHICH IS CLOSE TO CURRENT FORECAST AND A LITTLE WARMER THAN
MOST MOS GUIDANCE. THIS SEEMS REASONABLE. THERE SHOULD BE A LOT OF
SUNSHINE AT LEAST THROUGH MID DAY AND THEN A LITTLE MORE CLOUDINESS
THIS AFTERNOON. REST OF NEAR TERM SEEMS TO BE ON TRACK.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
ISSUED AT 303 AM EST FRI FEB 27 2015
DRY CONDITIONS EXPECTED TONIGHT AND SATURDAY AS SURFACE HIGH
PRESSURE GRADUALLY SHIFTS OFF TO THE EAST. MAIN ITEM OF INTEREST
DURING THIS PERIOD IS A SHORT WAVE TROUGH THAT IS EXPECTED TO DROP
SOUTHEAST ACROSS THE GREAT LAKES SUNDAY NIGHT. THE SURFACE
REFLECTION ASSOCIATED WITH THIS FEATURE DOESN/T LOOK TOO
IMPRESSIVE...BUT MODELS SUGGEST A 40 KT LOW LEVEL JET ASSOCIATED
WITH THIS FEATURE...WHICH SHOULD PROVIDE QUITE A BIT OF LIFT.
WILL BRING IN HIGH POPS BY LATE SATURDAY NIGHT AND SUNDAY BASED ON
ABOVE REASONING...WITH POPS TAPERING OFF SUNDAY NIGHT AS MAIN LIFT
PUSHES OFF TO THE EAST. OPERATIONAL MODELS SUGGEST MAINLY SNOW OVER
ABOUT THE NORTHERN HALF OF THE FORECAST AREA...WITH MORE OF A MIX
OVER THE SOUTHERN HALF...WHICH GOES ALONG WITH THE PREVIOUS
FORECAST. HOWEVER...THE ENSEMBLES SUGGEST A STRONGER PUSH OF WARM
AIR IS POSSIBLE...WITH POTENTIAL FOR RAIN AS FAR NORTH AS THE
NORTHERN ZONES BY SUNDAY. CAN/T RULE OUT THESE SOLUTIONS GIVEN THE
STRENGTH OF THE LOW LEVEL JET. FOR NOW...WILL STICK WITH THE
PREVIOUS FORECAST REGARDING PRECIPITATION TYPES AND MONITOR THE
TRENDS. SEVERAL INCHES OF SNOW ARE POSSIBLE WITH THIS
SYSTEM...ESPECIALLY OVER THE NORTHERN ZONES.
BASED ON LOW LEVEL THICKNESSES...THE GFS MOS TEMPERATURE GUIDANCE
FOR TONIGHT AND SATURDAY LOOK A LITTLE COLD. WILL BUMP UP THE
GUIDANCE A FEW DEGREES IN THOSE PERIODS. THE GUIDANCE HIGHS ON
SUNDAY LOOK TOO WARM CONSIDERING EXPECTED PRECIPITATION...SO WILL
NUDGE THOSE NUMBERS DOWN ABOUT A CATEGORY.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
ISSUED AT 230 PM EST FRI FEB 27 2015
MODELS ARE CLOSE ENOUGH THAT THE SUPERBLEND INITIALIZATION WAS
ACCEPTED FOR MOST ITEMS.
SOUTHWEST FLOW ALOFT IN THE FIRST PART OF THE LONG TERM WILL ALLOW
NEAR TO ABOVE AVERAGE TEMPERATURES AS AN AREA OF LOW PRESSURE MOVES
TO THE NORTH OF CENTRAL INDIANA. HOWEVER AN UPPER TROUGH WILL MOVE
INTO THE AREA FOR THE END OF THE PERIOD ALLOWING WELL BELOW NORMAL
TEMPERATURES ONCE AGAIN.
LOOKS LIKE PRECIPITATION WILL MAINLY ARRIVE OVERNIGHT MONDAY NIGHT
INTO EARLY TUESDAY. MODELS STILL ARE BRINGING IN WARM AIR ALOFT
QUICKLY...SO MIXED PRECIPITATION TO FREEZING RAIN LOOKS TO BE THE
PRECIPITATION TYPE MONDAY NIGHT.
SURFACE TEMPERATURES STILL LOOK TO BE COLD TUESDAY MORNING SO KEPT
THE FREEZING RAIN MENTION THEN. AS WARM AIR AT THE SURFACE FINALLY
ARRIVES RAIN WILL FALL LATER TUESDAY MORNING THROUGH THE REMAINDER
OF THE DAY. COULD BE ENOUGH RAIN TO CAUSE SOME FLOODING ISSUES GIVEN
THE FROZEN GROUND. WILL CONTINUE TO MONITOR CLOSELY.
MODELS DIFFER IN SPEED OF COLD AIR RETURNING TUESDAY NIGHT BUT STILL
FEEL IT A MIX OF RAIN AND SNOW IS WARRANTED AS PRECIPITATION TYPE
MOST AREAS. AS A WAVE RIDES ALONG THE FRONT ON WEDNESDAY
PRECIPITATION CHANCES WILL CONTINUE...WITH CHANCES FOR SNOW
NORTHWEST AND RAIN/SNOW SOUTHEAST.
THURSDAY AND FRIDAY LOOK TO BE DRY AND COLD WITH HIGH PRESSURE
MOVING IN.
&&
.AVIATION /DISCUSSION FOR 271800Z TAF ISSUANCE/...
ISSUED AT 1142 AM EST FRI FEB 27 2015
VFR EXPECTED THROUGH THE PERIOD WITH WINDS GENERALLY LESS THAN 10KT.
SCATTERED /TO PERHAPS BRIEFLY BROKEN AT KIND/KBMG/ CU FIELD WILL
DISSIPATE WITH LOSS OF HEATING NEAR SUNSET. OTHERWISE MID AND HIGH
CLOUDS WILL INCREASE TONIGHT AND SATURDAY AHEAD OF NEXT SYSTEM.
WINDS WILL BECOME LIGHT THIS EVENING AND THEN SOUTHEAST AT LESS THAN
10KT SATURDAY.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
IND...NONE.
&&
$$
SYNOPSIS...JAS
NEAR TERM...JH
SHORT TERM...JAS
LONG TERM....50
AVIATION...50
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AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1142 AM EST FRI FEB 27 2015
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 303 AM EST FRI FEB 27 2015
HIGH PRESSURE IS EXPECTED ACROSS THE AREA THROUGH SATURDAY. A
FRONTAL SYSTEM IS EXPECTED TO MOVES THROUGH THE AREA FRONT SATURDAY
NIGHT INTO SUNDAY NIGHT. A STRONGER LOW PRESSURE SYSTEM MAY AFFECT
THE AREA TOWARDS THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 1025 AM EST FRI FEB 27 2015
CANCELLED WIND CHILL ADVISORY AS WIND CHILLS ARE NO LONGER REACHING
ADVISORY CRITERIA.
OTHERWISE...SATELLITE INDICATES MOSTLY CLEAR SKIES WERE ACROSS MOST
OF THE AREA. RUC MODEL SOUNDINGS INDICATE CU MAY INCREASE THIS
AFTERNOON CAUSING SKIES TO BECOME PARTLY CLOUDY.
RUC SOUNDINGS INDICATE HIGHS FROM MIDDLE TEENS NORTH TO AROUND 20
SOUTH WHICH IS CLOSE TO CURRENT FORECAST AND A LITTLE WARMER THAN
MOST MOS GUIDANCE. THIS SEEMS REASONABLE. THERE SHOULD BE A LOT OF
SUNSHINE AT LEAST THROUGH MID DAY AND THEN A LITTLE MORE CLOUDINESS
THIS AFTERNOON. REST OF NEAR TERM SEEMS TO BE ON TRACK.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
ISSUED AT 303 AM EST FRI FEB 27 2015
DRY CONDITIONS EXPECTED TONIGHT AND SATURDAY AS SURFACE HIGH
PRESSURE GRADUALLY SHIFTS OFF TO THE EAST. MAIN ITEM OF INTEREST
DURING THIS PERIOD IS A SHORT WAVE TROUGH THAT IS EXPECTED TO DROP
SOUTHEAST ACROSS THE GREAT LAKES SUNDAY NIGHT. THE SURFACE
REFLECTION ASSOCIATED WITH THIS FEATURE DOESN/T LOOK TOO
IMPRESSIVE...BUT MODELS SUGGEST A 40 KT LOW LEVEL JET ASSOCIATED
WITH THIS FEATURE...WHICH SHOULD PROVIDE QUITE A BIT OF LIFT.
WILL BRING IN HIGH POPS BY LATE SATURDAY NIGHT AND SUNDAY BASED ON
ABOVE REASONING...WITH POPS TAPERING OFF SUNDAY NIGHT AS MAIN LIFT
PUSHES OFF TO THE EAST. OPERATIONAL MODELS SUGGEST MAINLY SNOW OVER
ABOUT THE NORTHERN HALF OF THE FORECAST AREA...WITH MORE OF A MIX
OVER THE SOUTHERN HALF...WHICH GOES ALONG WITH THE PREVIOUS
FORECAST. HOWEVER...THE ENSEMBLES SUGGEST A STRONGER PUSH OF WARM
AIR IS POSSIBLE...WITH POTENTIAL FOR RAIN AS FAR NORTH AS THE
NORTHERN ZONES BY SUNDAY. CAN/T RULE OUT THESE SOLUTIONS GIVEN THE
STRENGTH OF THE LOW LEVEL JET. FOR NOW...WILL STICK WITH THE
PREVIOUS FORECAST REGARDING PRECIPITATION TYPES AND MONITOR THE
TRENDS. SEVERAL INCHES OF SNOW ARE POSSIBLE WITH THIS
SYSTEM...ESPECIALLY OVER THE NORTHERN ZONES.
BASED ON LOW LEVEL THICKNESSES...THE GFS MOS TEMPERATURE GUIDANCE
FOR TONIGHT AND SATURDAY LOOK A LITTLE COLD. WILL BUMP UP THE
GUIDANCE A FEW DEGREES IN THOSE PERIODS. THE GUIDANCE HIGHS ON
SUNDAY LOOK TOO WARM CONSIDERING EXPECTED PRECIPITATION...SO WILL
NUDGE THOSE NUMBERS DOWN ABOUT A CATEGORY.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
ISSUED AT 258 AM EST FRI FEB 27 2015
ACTIVE PATTERN CONTINUES THROUGH THE FIRST HALF OF NEXT WEEK AS
PIECES OF ENERGY ALOFT EJECT OUT OF THE TROUGH OVER THE WESTERN U S
FOLLOWED BY THE TROUGH AXIS ITSELF MOVING EAST INTO THE REGION BY
THE END OF THE PERIOD. HIGH CONFIDENCE IN A SIGNIFICANT WEATHER
IMPACT FOR CENTRAL INDIANA AND THE OHIO VALLEY MONDAY NIGHT THROUGH
WEDNESDAY.
STRONG HIGH PRESSURE ARRIVES IN THE WAKE OF THE LATE WEEKEND SYSTEM
FOR MONDAY...AND SHOULD SERVE TO GIVE THE REGION A BREATHER BETWEEN
WEATHER SYSTEMS ON THE ORDER OF 18 TO 24 HOURS. SURFACE WAVE SET
TO SPIN UP OVER THE CENTRAL ROCKIES MONDAY NIGHT AS ENERGY EJECTS
OUT FROM THE PARENT TROUGH. THIS FEATURE WILL SWING E/NE AND TRACK
QUICKLY INTO THE REGION BY TUESDAY EVENING AND BRING WITH IT A
PLETHORA OF MESSY PROBLEMS FOR CENTRAL INDIANA. RIDGING DEVELOPING
DOWNSTREAM OF THE TROUGH SUPPORTS MORE AMPLIFIED FLOW WITH THE
SURFACE WAVE TRACKING THROUGH OR NORTH OF THE FORECAST AREA. OP GFS
SHOWING ITS USUAL PROGRESSIVE BIAS IN THE MID RANGE IN BRINGING
PRECIP IN TOO QUICKLY...ESPECIALLY CONSIDERING THE STRENGTH OF THE
DEPARTING HIGH. LIKE THE LOOK OF THE ECMWF/GGEM WHICH DELAYS MOST
PRECIP UNTIL AFTER MIDNIGHT MONDAY NIGHT.
WARM ADVECTION WILL ALREADY BE ONGOING WHEN PRECIP STARTS...AND
EXPECT PRECIP TYPE ISSUES FROM THE GET GO WITH A GROWING LIKELIHOOD
THAT FREEZING RAIN IS THE PREDOMINANT PRECIP TYPE INTO TUESDAY
MORNING. THE REFRESHED SNOWPACK COURTESY OF THE WEEKEND STORM WILL
BE A SIGNIFICANT FACTOR IN DURATION OF FROZEN PRECIP AS THE NEAR
SURFACE/GROUND TEMPS WILL LAG THE LOW LEVEL TEMP RISES. MODEL
THERMAL PROFILES ARE ALREADY SUGGESTIVE THAT IT MAY TAKE UNTIL
MIDDAY TUESDAY IN SOME PORTIONS OF THE REGION TO WARM SUFFICIENTLY
FOR ALL RAIN. IF THE IMPACT OF THE SNOWCOVER IS UNDERMINED BY THE
MODELS WHATSOEVER...THE ICING POTENTIAL COULD BE EVEN MORE
SIGNIFICANT. DO NOT EXPECT TO HAVE A GOOD HANDLE ON THIS UNTIL LATER
IN THE WEEKEND.
WHILE THE ICING THREAT IS A GROWING ISSUE...AN EXTENDED PERIOD OF
HEAVY RAIN OVER A FROZEN GROUND AND SNOW COVER POSES EVEN GREATER
CONCERNS. COPIOUS AMOUNTS OF MOISTURE WILL BE DRAWN NORTH INTO THE
REGION AHEAD OF THE APPROACHING SURFACE WAVE TUESDAY AND TUESDAY
NIGHT. PRECIP WATER VALUES ARE PARTICULARLY ALARMING...MAXING OUT
BETWEEN 1.25 AND 1.50 INCHES TUESDAY EVENING. THESE LEVELS WOULD
PLACE THE REGION NEAR AND ABOVE THE 99TH PERCENTILE FOR
CLIMATOLOGICAL PRECIP WATER VALUES IN MARCH. POTENTIAL FOR
CONVECTIVE ELEMENTS TO THE PRECIP AS WELL AND MAY NEED TO ADD AN
ISOLATED THUNDER MENTION INTO THE FORECAST FOR TUESDAY
AFTERNOON/NIGHT. 1-2 INCHES OF RAINFALL CERTAINLY LOOK PLAUSIBLE AND
WITH MOST OF THIS BEING CONVERTED TO PURE RUNOFF WITH THE FROZEN
GROUND...FLOODING CONCERNS ARE VALID. FRONTAL BOUNDARY SHOULD
FINALLY MOVE EAST WEDNESDAY WITH PRECIP ENDING LATE DAY...LIKELY AS
A RAIN/SNOW MIX. MUCH COLDER AIR WILL THEN RETURN FOR THE END OF THE
WEEK.
STILL PLENTY TO HASH OUT AND THE WEEKEND WINTER STORM WILL HAVE SOME
SAY IN HOW THIS ALL TRANSPIRES. AS STATED ABOVE THOUGH...CONFIDENCE
IS HIGH IN SIGNIFICANT WEATHER IMPACTS FOR CENTRAL INDIANA MONDAY
NIGHT THROUGH WEDNESDAY...WITH ICING...HEAVY RAIN AND FLOODING ALL
POTENTIAL CONCERNS. ENCOURAGE HOOSIERS TO STAY ABREAST OF THE
FORECAST OVER THE NEXT FEW DAYS.
&&
.AVIATION /DISCUSSION FOR 271800Z TAF ISSUANCE/...
ISSUED AT 1142 AM EST FRI FEB 27 2015
VFR EXPECTED THROUGH THE PERIOD WITH WINDS GENERALLY LESS THAN 10KT.
SCATTERED /TO PERHAPS BRIEFLY BROKEN AT KIND/KBMG/ CU FIELD WILL
DISSIPATE WITH LOSS OF HEATING NEAR SUNSET. OTHERWISE MID AND HIGH
CLOUDS WILL INCREASE TONIGHT AND SATURDAY AHEAD OF NEXT SYSTEM.
WINDS WILL BECOME LIGHT THIS EVENING AND THEN SOUTHEAST AT LESS THAN
10KT SATURDAY.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
IND...NONE.
&&
$$
SYNOPSIS...JAS
NEAR TERM...JH
SHORT TERM...JAS
LONG TERM....RYAN
AVIATION...50
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AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1110 AM CST FRI FEB 27 2015
.UPDATE...
ISSUED AT 721 AM CST FRI FEB 27 2015
RECORD LOW COLD TEMPERATURES OCCURRED TONIGHT WITH THE CLEAR SKIES
AND FRESH SNOWFALL. WIND CHILLS IN A FEW LOCATIONS WERE BELOW -30.
THE ONLY CHANGE TO THE FORECAST WERE THE TEMP TRENDS. EXPECT A
WARM UP ONCE THE SUN STARTS HEATING AS IT IS STARTING TO BECOME THE
SEASON OF HIGHER SUN ANGLES. WIND CHILL ADVISORY SHOULD STILL BE
OKAY THROUGH 9AM...A FEW SITES MAY LINGER WITH SUB -20 WIND CHILLS
THROUGH 10AM.
&&
.SYNOPSIS...
ISSUED AT 307 AM CST FRI FEB 27 2015
HIGH PRESSURE WAS MOVING INTO THE CENTRAL PLAINS EARLY THIS
MORNING. WITH FRESH SNOWFALL AND CLEAR SKIES TEMPERATURES HAVE
PLUMMETED THIS MORNING TO QUITE POSSIBLY ONE OF THE COLDEST NIGHTS
OF THE YEAR. WINDS HAVE STAYED UP...WHICH HAS LEAD TO WIDESPREAD
WIND CHILLS BETWEEN 20 AND 30 BELOW ZERO WITH A FEW POCKETS OF 30
BELOW OR LOWER WIND CHILLS. WINDS ARE STARTING TO WANE AND
TEMPERATURES SHOULD DROP MORE.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 307 AM CST FRI FEB 27 2015
MAIN FORECAST CONCERN FOR THE SHORT TERM ARE TEMPERATURES TODAY
AND TONIGHT ACROSS THE AREA. WITH HIGH PRESSURE IN PLACE AND FRESH
SNOW COVER...GUIDANCE IS OF LITTLE HELP FOR TEMPERATURE FORECASTS.
AS FAR AS THE SYNOPTIC PATTERN IS CONCERNED...H5 RIDGING IS
BUILDING INTO THE CENTRAL UNITED STATES AS A SURFACE HIGH IS PROG
TO MOVE DIRECTLY OVER OUR CWA TODAY. WINDS SHOULD WANE...HOWEVER
COLD AIR AND FRESH SNOWFALL WILL LEAD TO COLD TEMPERATURES TODAY
AND TONIGHT. MODELS ARE OF LITTLE HELP...THIS MORNING FOR LOWS I
LOADED THE OBS AND THEN MADE TWEAKS FROM THERE AS THE RUC WAS THE
ONLY MODEL COLD ENOUGH WITH TEMPS. FOR TODAY AND TONIGHT...WENT
WITH THE ALLBLEND AND THEN TWEAKED TEMPERATURES FROM THERE. WIND
CHILLS TONIGHT SUGGEST THE NEED FOR ANOTHER WIND CHILL ADVISORY
FOR AREAS NORTH OF I80. WILL DEFER TO THE DAY TO SHIFT TO DECIDE
TO ISSUE THIS AS THERE IS ALREADY ONE OUT.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 307 AM CST FRI FEB 27 2015
TWO STORM SYSTEMS WILL IMPACT THE EXTENDED FORECAST...AND BOTH
CONTAIN POTENTIAL WINTER IMPACTS. AT THIS TIME...BOTH SYSTEMS ARE
RELATIVELY POOR IN CONFIDENCE OF EXACT DETAILS CONCERNING THESE
IMPACTS.
TO BEGIN THE EXTENDED...HIGH PRESSURE WILL BE MOVING OFF TO THE EAST
SATURDAY...AND WITH A VERY COLD START TO THE DAY...THE WEAK WAA WILL
LIKELY ONLY RESULT IN HIGHS IN THE MID TEENS NORTH TO MID 20S
SOUTH...DESPITE A HEALTHY AMOUNT OF LATE FEBRUARY SUNSHINE IN THE
MORNING. WARM ADVECTION BY AFTERNOON...WILL BRING MID LEVEL MOISTURE
NORTHWARD...WITH SOME MODELS CONTINUING TO BRUSH OUR SOUTHWEST WITH
DEEPER SATURATION BY LATE AFTERNOON. THE MODEL BLEND SHOWS FAR MORE
SIGNIFICANT MOISTURE ADVECTION BY SATURDAY NIGHT...AND I WILL
CONTINUE TO HIGHLIGHT THAT PERIOD THROUGH SUNDAY WITH HIGH POPS.
THIS EVENT IS GOING TO BE ALL SNOW...AND SHOULD HAVE RATIOS IN THE
12 TO 15 TO 1 RANGE...THUS AMOUNTS FROM SATURDAY EVENING THROUGH
SUNDAY AFTERNOON SHOULD RANGE FROM AROUND 1 INCH NORTHWEST...TO 2 TO
3 INCHES FROM IOWA CITY THROUGH THE QUAD CITIES TO STERLING...TO 3
TO 5 INCHES OVER FAR SOUTHEAST IOWA NORTHEAST MISSOURI TO NEAR
PRINCETON ILLINOIS. WHILE THOSE AMOUNTS ARE SUPPORTED BY THE MOST
LIKELY BLEND OF GUIDANCE THAT IS INDICATED AT THIS TIME...I AM NOT
CONFIDENT IN THEM YET. THE EVENT IS LIKELY GOING TO FALL INTO THE
ADVISORY RANGE...ESPECIALLY DUE TO THE LONGER THAN NORMAL DURATION
FOR THESE RANGE OF AMOUNTS. LOOKING AT UNCERTAINTY...THE CANADIAN
MODEL IS FARTHER SOUTH THAN THE ECMWF AND GFS...AND KEEPS THE
NORTHERN 3/4S OF THE CWA DRY...THUS ANOTHER REASON FOR HOLDING OFF
ON ANY EARLY HEADLINE AT THIS TIME. THE 06Z NAM...THROUGH 12Z
SUNDAY...ALSO KEEPS THE BULK OF MOISTURE AND FORCING SOUTH.
MONDAY WILL BE A BREAK BETWEEN LOW CONFIDENCE SYSTEM...AS THE DEEP
WESTERN TROF BECOMES EVEN MORE AMPLIFIED. THE MODELS HAVE SHOWN VERY
LITTLE CONSISTENCY OVER THE PAST FEW DAYS AND THROUGH TONIGHT WITH
RESPECT TO THE LOW TRACK...UPPER ENERGY TRACK...AND BAROCLINICITY OF
THIS POTENTIAL SYSTEM. ONE FEATURE THAT HAS BEEN SHOWN
CONSISTENTLY...HAS BEEN MOISTURE...WITH A SYNOPTIC SIGNAL OF AN OPEN
GULF OF MEXICO...AND EVEN OPEN CARIBBEAN. THE HIGH AMOUNTS OF
AVAILABLE MOISTURE ARE REASONS SUPPORTING LIKELY POPS MONDAY NIGHT
AND TUESDAY. WHILE NOT CONFIDENT IN THERMAL TRANSITION TIMING...IT
IS A BEST MODEL BLEND...AND CONCEPTUAL MODEL FIT FOR PCPN TO BEGIN
AS A WINTRY MIX OF SNOW/SLEET/FREEZING RAIN MONDAY
NIGHT...TRANSITIONING TO RAIN TUESDAY...THEN BACK TO SNOW AGAIN
TUESDAY NIGHT. THIS WET MESS COULD BE HIGH IMPACT...OR COULD BE
LARGELY BENIGN. IT IS VERY DIFFICULT TO TELL...AND WILL KEEP A
HEALTHY DOSE OF UNCERTAINTY IN OUR PRODUCTS.
FOLLOWING THIS SYSTEM...COLDER DRY WEATHER SETTLES BACK IN THE A FEW
DAYS BEFORE MODERATION LOOKS TO OCCUR IN ZONAL FLOW.
ERVIN
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1109 AM CST FRI FEB 27 2015
VFR CONDITIONS WILL BE SEEN THROUGH 18Z/28 AS ARCTIC HIGH PRESSURE
MOVES INTO THE OHIO VALLEY.
&&
.CLIMATE...
ISSUED AT 307 AM CST FRI FEB 27 2015
COULD SEE RECORD LOWS THIS MORNING AT A FEW SITES AND POSSIBLY
AGAIN TONIGHT AT OTHER SITES. HERE ARE THE RECORDS FOR TONIGHT.
RECORD LOWS FOR FEBRUARY 28...
MOLINE.........-9 IN 1962
CEDAR RAPIDS...-17 IN 1962
DUBUQUE........-10 IN 1962
BURLINGTON.....-7 IN 1962
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...GIBBS
SYNOPSIS...GIBBS
SHORT TERM...GIBBS
LONG TERM...ERVIN
AVIATION...08
CLIMATE...GIBBS
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1036 AM MST FRI FEB 27 2015
.UPDATE...
ISSUED AT 842 AM MST FRI FEB 27 2015
UPDATED THE FORECASTS TO REMOVE THE WIND CHILL ADVISORY ACROSS KIT
CARSON AND CHEYENNE COUNTIES AS WIND CHILL READINGS WILL GRADUALLY
RISE THE REST OF TODAY. OTHERWISE...LIGHT SNOW CONTINUES OVER THE
AREA. 12Z NAM SHOWS SNOW WILL DECREASE FROM NORTH TO SOUTH AFTER
18Z...THEN NEXT SHORT WAVE TROUGH WILL MOVE ACROSS SOUTHWEST
KANSAS TONIGHT BRINGING ANOTHER GOOD CHANCE OF SNOW...ESPECIALLY
SOUTH OF INTERSTATE 70.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY NIGHT)
ISSUED AT 323 AM MST FRI FEB 27 2015
EARLY MORNING WV IMAGERY AND RAP H5 ANALYSIS SHOW SHORTWAVE TROUGH
MOVING INTO NEBRASKA. MOISTURE PLUME EXTENDS ACROSS WESTERN KANSAS
AND EASTERN COLORADO. AT THE SURFACE 1038 MB HIGH PRESSURE IS
CENTERED OVER THE MISSOURI RIVER VALLEY NEAR THE NEBRASKA AND IOWA
STATE LINE. SOUTHEASTERLY FLOW IS IN PLACE ACROSS THE CWA WITH A
TIGHT TD GRADIENT FROM THE WEST (AROUND 10F) TO THE NORTHEAST (-2F).
REGARDING WIND CHILL ADVISORY THIS MORNING AND THE POSSIBILITY
TONIGHT...WINDS ARE STILL EXPECTED TO INCREASE IN THE 12-15Z TIME
PERIOD THIS MORNING. BASED ON CURRENT WIND FORECAST...IF TEMPS IN
THE ADVISED AREA WERE TO DROP TO AROUND 4F OR LOWER WINDS WOULD
SUPPORT -15F WIND CHILLS. SHORT RANGE GUIDANCE GENERALLY KEEPS
TEMPS STEADY IN THE WEST WHERE THE HIGHER WINDS WILL BE AND WIND
CHILLS IN THE -10F OR WARMER RANGE. AT THIS POINT I SEE NO REASON
TO CHANGE ADVISORY CONSIDERING HOW CLOSE IT WILL BE. CONDITIONS
TONIGHT/EARLY SATURDAY MORNING COULD BE SIMILAR AS THIS
MORNING...WITH CLOUD COVER THE LIMITING FACTOR ON IDEAL RADIATIONAL
CONDITIONS. IT COULD BE CLOSE TO ADVISORY CRITERIA...BUT WITH THE
AMOUNT OF UNCERTAINTY AND ONGOING ADVISORY THIS MORNING I PREFER
TO LET THE CURRENT ONE PLAY OUT.
TODAY...LIGHT SNOW HAS BEEN REPORTED ACROSS EASTERN COLORADO AND
PARTS OF NW KANSAS EARLY THIS MORNING...WITH LIGHT ACCUMULATIONS
APPARENT ON WEB CAMS AND OBSERVED AT WFO. SHORT RANGE GUIDANCE
SHOWS THIS ACTIVITY CONTINUING TO TRANSITION SOUTHEAST ACROSS THE
REGION AS SHORTWAVE SLIDES EAST. CONSIDERING THE LIGHT NATURE OF
THE RADAR RETURNS ACROSS THE CWA IT IS HARD TO JUDGE HOW MUCH
ACCUMULATION IS ACTUALLY OCCURRING AND TREND IN GUIDANCE HAS BE
TOWARDS LOWER VALUES. MAIN THREAT FOR MEANINGFUL ACCUMULATIONS
WILL BE BEFORE 18Z...WITH CHANCE FOR MEASURABLE SNOW DIMINISHING
AFTERWARDS. IT APPEARS 1-2" SHOULD STILL BE THE HIGH END OF
ACCUMULATION FROM NOW THROUGH MIDDAY (MAINLY ALONG AND SOUTH OF
I-70). AS WINDS INCREASE WE COULD STILL SEE BLOWING SNOW
DEVELOP...HOWEVER THIS SHOULD BE AN ISOLATED THREAT AND TIED TO
ANY NEW SNOWFALL RATHER THAN OLD/CRUSTED OVER SNOW PACK. I KEPT
PATCHY BLOWING SNOW MENTION AND DO NOT THINK THERE IS A NEED FOR
ADVISORY AS VIS RESTRICTIONS FROM BLOWING SNOW WILL BE ISOLATED.
TONIGHT-SUNDAY NIGHT...H3 JET BEGINS TO TRANSITION NORTHWARD OVER
THE CWA AS TROUGH DEEPENS ACROSS THE SW US. RESULT WITH BE BROAD
AREA OF WEAK FORCING DEVELOPING ACROSS THE CWA...WITH BETTER FORCING
TIED TO MID LEVEL CIRCULATIONS ROTATING THROUGH THE MEAN FLOW.
GUIDANCE HAS TRENDED TOWARDS BETTER PRECIP SIGNALS EITHER WELL WEST
OF THE CWA...OR SOUTHEAST OF THE CWA. WE COULD STILL SEE LIGHT
ACCUMULATIONS...HOWEVER BEST CHANCE SEEMS TO BE IN OUR
EASTERN/SOUTHEAST CWA AND AMOUNTS HAVE TRENDED LOWER WITH 1-2" ON
THE HIGHER END OF TOTAL ACCUMULATIONS SATURDAY/SATURDAY NIGHT.
CONSIDERING THE TRENDS AND AMOUNT OF UNCERTAINTY I TRENDED POPS
LOWER THROUGH ALL THESE PERIODS AND ADJUSTED HIGHEST POPS TO BE IN
THE EASTERN CWA SATURDAY AFTERNOON/EVENING CORRELATING WITH BEST
PRECIP SIGNAL.
REGARDING TEMPS...AS HAS BEEN THE CASE WE SHOULD SEE BELOW NORMAL
TEMPERATURES CONTINUE WITH ONLY SLOW MODERATION TO TEMPS ALOFT
SATURDAY/SUNDAY AS SW FLOW ALOFT DEVELOPS ACROSS THE SOUTHERN PLANS
OVER THE TOP OF THE PERSISTENT ARCTIC AIR MASS. CLOUD COVER AND THE
POSSIBILITY OF PRECIP CONTINUES TO COMPLICATE DAYTIME/NIGHTTIME
TEMPS...SO ONLY MADE MINOR ADJUSTMENTS TO REFLECT CURRENT
CONSENSUS/MODEL TRENDS. LITTLE CHANGE FROM PREVIOUS FORECAST.
.LONG TERM...(MONDAY THROUGH THURSDAY NIGHT)
ISSUED AT 323 AM MST FRI FEB 27 2015
MODELS HAVE THE JET POSITIONED SLIGHTLY FURTHER NORTH DURING THE
FIRST PART OF NEXT WEEK WHICH MAY END UP KEEPING TEMPERATURES
SLIGHTLY WARMER AND WILL LIKELY ALSO MOVE THE JET ENHANCED AREA OF
PRECIPITATION FURTHER NORTH ACROSS THE FORECAST AREA. MODELS ARE
ENDING PRECIPITATION ACROSS THE FORECAST AREA WEDNESDAY MORNING AND
HAVE DRY CONDITIONS AFTER THAT.
THE UPPER LOW CENTER THAT STARTS OUT AS A CLOSED LOW OVER OVER
SOUTHERN CALIFORNIA ON SUNDAY EJECTS OUT ACROSS THE SOUTHERN ROCKIES
AND CENTRAL HIGH PLAINS REGION AS AN OPEN WAVE ON MONDAY NIGHT/EARLY
TUESDAY. THIS IS AHEAD OF A SHORT WAVE TROUGH DROPPING INTO THE
BASE OF THE MAIN TROUGH AXIS OVER BAJA AND ANOTHER LOW IN PHASE WITH
THE MAIN UPPER TROUGH THAT BEGINS MOVING FROM SOUTH CENTRAL CANADA
INTO THE NORTHERN PLAINS. THE ENTIRE MAJOR TROUGH AXIS SWEEPS EAST
OF THE ROCKIES AND ACROSS THE PLAINS WEDNESDAY EVENING WITH
NORTHWEST FLOW AND RIDGING TO EXTEND ACROSS THE ROCKIES INTO THE
HIGH PLAINS REGION BY THURSDAY AND THURSDAY NIGHT.
A SURFACE LOW AND COLD FRONT ASSOCIATED WITH THE UPPER SHORT WAVE
TROUGH LIFTING ACROSS THE REGION ON TUESDAY USHERS IN COOLER
TEMPERATURES ACROSS FORECAST AREA AND SPREADS THE PRECIPITATION
SOUTHWARD ACROSS THE FORECAST AREA TUESDAY NIGHT AND WEDNESDAY
MORNING. SNOW WILL COME TO AN END ON WEDNESDAY WITH MUCH COLDER
TEMPERATURES AS SURFACE HIGH PRESSURE MOVES INTO THE REGION. THE
COLD AIR SHOULD NOT LAST LONG AS RETURN FLOW AROUND THE EXITING HIGH
PRESSURE AREA TURNS SOUTHWESTERLY ACROSS THE FORECAST AREA AND THE
RIDGE ALOFT BUILDS IN.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1032 AM MST FRI FEB 27 2015
LIGHT SNOW CONTINUES AT KGLD...AND RADAR IMAGERY INDICATES THE
SNOW WILL CONTINUE A FEW MORE HOURS. VFR CONDITIONS ARE REPORTED
AT KMCK...BUT LIGHT SNOW IS JUST TO THE WEST. BASED ON SHORT
RANGE MODELS...ENDED THE SNOW AT KGLD/KMCK AFTER 21Z. SNOW WILL
REDEVELOP AFTER 09Z WHEN THE NEXT SHORTWAVE TROUGH MOVES ACROSS
THE AREA. FOR THE NEXT 12 HOURS...CONDITIONS WILL BE MOSTLY MVFR
DUE CEILINGS AND PERIODS OF LIGHT SNOW...THEN DROPPING TO IFR
LATER TONIGHT DUE TO A BETTER CHANCE OF SNOW.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...MENTZER
SHORT TERM...DR
LONG TERM...99
AVIATION...MENTZER
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1241 PM EST FRI FEB 27 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 402 AM EST FRI FEB 27 2015
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A NW FLOW ALOFT
OVER THE UPR GREAT LKS TO THE SW OF CLOSED H5 LO OVER NRN QUEBEC.
SHRTWV RDG AXIS STRETCHING FM THE NRN PLAINS INTO NW ONTARIO IS
SUPPORTING A SFC HI PRES STRETCHING FM THE NRN PLAINS INTO IOWA. UPR
MI IS DOMINATED BY A DRY WNW LLVL FLOW E OF THIS HI CENTER /00Z
PWATS UPSTREAM ARE GENERALLY 0.05 TO 0.10 INCH...NO MORE THAN 50 PCT
OF NORMAL/. COMBINATION OF THE DRYNESS OF THE UPSTREAM AIRMASS...00Z
INL AND YPL RAOBS SHOW AN INVERTED V T/TD PROFILE BLO SUBSIDENCE
INVRN NEAR H9...AND EXTENSIVE ICE COVER OVER LK SUP HAS GREATLY
DIMINISHED THE LES. IN FACT...IR STLT IMAGERY SHOWS ONLY PATCHY LK
CLDS STREAMING INTO AREAS E OF MUNISING. 00Z H85 TEMPS OVER THE AREA
RANGE FM -23C AT GRB TO -19C AT INL/YPL AND THEN UP TO -16C AT THE
PAS MANITOBA. UNDER THE MOCLR SKIES/DRY ARCTIC AIRMASS...TEMPS HAVE
FALLEN WELL BLO ZERO OVER THE INTERIOR AND AS LO AS -25F TO -30F AT
THE MORE SHELTERED RURAL SPOTS. WINDS ARE STIRRING A BIT MORE NEAR
LK SUP UNDER A TIGHTER PRES GRADIENT...AND SOME OF THE MORE EXPOSED
LOCATIONS THERE ARE INDICATING WIND CHILLS AS LO AS -25F.
MAIN FCST CONCERNS THRU TNGT WL BE ON TEMPS. OPTED TO ISSUE AN SPS
TO COVER WIND CHILLS NEAR ADVY CRITERIA AT THE MORE EXPOSED
LOCATIONS NEAR LK SUP THIS MRNG.
TODAY...AS SHRTWV RDG TO THE NW SLIDES TO THE SE...SFC HI PRES
CENTER IS FCST TO SHIFT TO INDIANA/ILLINOIS BY 00Z SAT. THE
COMBINATION OF ONGOING SUBSIDENCE AHEAD OF THE SHRTWV RDG AND SOME
WAA AS THE SFC-H925 FLOW BACKS TO THE WSW...IS FCST TO RAISE H85
TEMPS UP TO -16 TO -17C BY THE END OF THE DAY. GIVEN ABSENCE OF MUCH
DIURNAL CU UPSTREAM YDAY AND LARGER SCALE SUBSIDENCE/WRMG AT H85...
SUSPECT THERE WL ONLY BE SOME SCT DIURNAL CLDS OVER THE INTERIOR
THIS AFTN. AS THE FLOW BACKS...LINGERING LK CLDS/ANY FLURRIES E OF
MUNISING THIS MRNG SHOULD SHIFT OUT OVER LK SUP IN THE AFTN. WITH A
GOOD DEAL OF SUNSHINE...GOING FCST HI TEMPS RECOVERING INTO THE
TEENS APPEAR TO BE ON TRACK.
TNGT...SFC HI PRES IS FCST TO SLIDE INTO THE MID ATLANTIC STATES BY
12Z SUN...WITH STEADY WSW WIND REMAINING IN PLACE UNDER THE TIGHT
PRES GRADIENT TO THE NW OF THIS FEATURE. ALOFT...UPR MI BE UNDER
CONTINUED SUBSIDENCE AHEAD OF ANOTHER SHRTWV RDG APRCHG FM THE W.
WITH A CONTINUED SLOW WARMING OF THE H85 TEMPS...AN ABSENCE OF ANY
SGNFT LLVL MSTR INFLOW AND GENERALY ACYC NATURE OF THE W FLOW...LK
CLDS OVER THE KEWEENAW SHOULD BE SCT AT BEST. ANY LK CLDS/LES OVER
THE E HALF OF THE LK SHOULD REMAIN OFFSHORE. PWAT IS FCST TO BE AOB
0.10 INCH...SO TENDED TO GO AOB THE LO END OF GUIDANCE FOR MIN TEMPS
/AS IS OBSVD THIS MRNG/ IN AREAS AWAY FM LK SUP...WHERE A STEADIER
WIND SHOULD LIMIT THE DIURNAL TEMP DROP.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 402 AM EST FRI FEB 27 2015
SATURDAY INTO SATURDAY NIGHT...A BROAD SURFACE HIGH PRESSURE SYSTEM
OVER MUCH OF THE GREAT LAKES REGION WILL REMAIN IN PLACE THROUGH THE
DAY SATURDAY. THIS WILL KEEP FAIRLY DRY AIR IN PLACE ALLOWING MOST
AREAS OF THE U.P. TO SEE SUNNY SKIES THROUGH THE DAY SATURDAY. BY
SATURDAY NIGHT...THE HIGH PRESSURE CENTER WILL SHIFT EASTWARD
STRETCHING FROM THE NORTHEAST U.S. SOUTHWARD ALONG THE EASTERN
SEABOARD. AT THIS HAPPENS...A WEAK SURFACE TROUGH/COLD FRONT WILL
APPROACH THE AREA FROM THE WEST. OVERALL MOISTURE APPEARS TO BE
LIMITED AND FOCUSED MAINLY TO THE SOUTH OF THE U.P. THEREFORE...ONLY
EXPECTING AN INCREASE IN CLOUD COVER SATURDAY NIGHT WITH ONLY A
SMALL CHANCE OF LIGHT SNOW ACROSS THE U.P. WITH LIMITED/WEAK FORCING.
SUNDAY THROUGH MONDAY...THE SURFACE TROUGH/WEAK COLD FRONT WILL
CONTINUE TO SHIFT EASTWARD AND PASS THROUGH THE UPPER PENINSULA
THROUGH THE DAY SUNDAY. AGAIN...MOISTURE WILL BE LIMITED ALONG THE
FRONT WITH CONTINUED WEAK FORCING. ONLY LIGHT SNOW IS EXPECTED
THROUGH THE DAY SUNDAY. BEHIND THE FRONT...AN UPPER LEVEL 500MB
TROUGH IS POISED TO SWING ACROSS THE U.P. SUNDAY NIGHT. AS THIS
HAPPENS...ENOUGH MOISTURE WILL REMAIN IN PLACE WITH VERY SLIGHT
ADDITIONAL MOISTURE ADDED FROM THE ICE COVER LAKE SUPERIOR TO ALLOW
A CHANCE OF LAKE EFFECT SNOW SHOWERS TO DEVELOP FOR WEST TO
NORTHWEST WIND FAVORED LOCATIONS. DELTA T VALUES WILL BE SUFFICIENT
FOR LAKE EFFECT WITH THE TROUGH AXIS SLIDING ACROSS...BUT LAKE
EFFECT INTENSITY WILL BE LIMITED TO AREAS THAT ANY BREAKS IN THE ICE
COVER OCCURS. ANY LAKE EFFECT THAT IS ABLE TO DEVELOP SUNDAY NIGHT
WILL BE SHORT LIVED AS MUCH DRIER AIR AND HIGH PRESSURE AT THE
SURFACE AND SLIGHT RIDGING ALOFT TO PUSH INTO THE UPPER GREAT LAKES
REGION DURING THE DAY MONDAY. THIS WILL FOR MAINLY SUNNY SKIES
DURING THE DAY MONDAY.
MONDAY NIGHT THROUGH WEDNESDAY...THE AFOREMENTIONED HIGH PRESSURE
SYSTEM WILL SHIFT TO THE LOWER GREAT LAKES...THEN THE EASTERN
SEABOARD MONDAY NIGHT. THIS WILL ALLOW A MORE MOIST SOUTHERLY FLOW
TO DEVELOP ON THE BACK SIDE OF THE HIGH. AT THE SAME TIME...A LOW
PRESSURE SYSTEM IS PROGGED TO DEVELOP OVER THE FOUR CORNERS REGION
OF THE U.S. ADDITIONALLY...ANOTHER STRONGER WAVE OF ENERGY IS
PROGGED TO PUSH ACROSS CENTRAL CANADA AND WORK TOWARD THE JAMES BAY
AREA. THERE ARE MODEL DIFFERENCES WITH THE PHASING OF THE TWO
SYSTEMS. THE 18Z/26 00Z/27 GFS IS MORE PROGRESSIVE WITH BOTH
SYSTEMS AND THE PHASING OF THE SYSTEMS. THIS WOULD PUSH SNOW INTO
THE AREA AS EARLY AS MONDAY EVENING ON ISENTROPIC UPGLIDE AND
INCREASED MOISTURE IN THE AREA. THE EC 12/26 00Z/27 IS MUCH SLOWER
WITH THE PHASING...KEEPING THE PRECIPITATION OUT OF THE AREA UNTIL
LATE MONDAY NIGHT INTO TUESDAY MORNING. THE BEST CHANCES GIVEN THE
OVERLAP OF THE TWO MODEL SOLUTIONS WOULD BE TUESDAY AFTERNOON INTO
TUESDAY NIGHT...ESPECIALLY FOR THE EAST HALF OF THE U.P. AT THIS
POINT...WILL STICK WITH CHANCE POPS AT LEAST UNTIL THE SYSTEM IS
SAMPLED BETTER OVER THE NEXT FEW DAYS.
WEDNESDAY NIGHT AND THURSDAY...BOTH THE EC AND GFS AGREE ON AN UPPER
LEVEL TROUGH AXIS ALONG WITH DEEPER MOISTURE LINGERING ACROSS THE
AREA DURING THIS TIME PERIOD. THE COLDER TEMPERATURES ALOFT ALONG
WITH ANY ADDITIONAL MOISTURE OFF LAKE SUPERIOR WILL ALLOW FOR LAKE
EFFECT SNOW CHANCES. AGAIN...THE EXACT LOCATION ALONG WITH INTENSITY
WILL BE LARGELY TIED TO ANY BREAKS IN THE ICE COVER ON LAKE
SUPERIOR. THE FAVORED LOCATIONS BASED SOLELY ON WIND WOULD BE FOR
THE WEST TO WEST NORTHWEST WIND FAVORED SNOW BELTS. GENERALLY...ANY
LAKE EFFECT SNOW SHOULD REMAIN FAIRLY LIGHT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1240 PM EST FRI FEB 27 2015
WITH DRY HIGH PRES DOMINATING...VFR CONDITIONS WILL BE THE RULE AT
KIWD/KCMX/KSAW THRU THIS FCST PERIOD. THERE MAY BE SOME DIURNAL
CU/STRATOCU THIS AFTN...MAINLY AT KCMX DUE TO VERY LIMITED MOISTURE
ADDED BY SOME BREAKS IN THE ICE COVER ON LAKE SUPERIOR.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 402 AM EST FRI FEB 27 2015
EXPECT WINDS TO BE UNDER 30 KTS THIS FORECAST PERIOD. LAKE SUPERIOR
IS MAINLY ICE COVERED THIS MORNING. ALTHOUGH SHIFTING WINDS UP TO 20
TO 25 KTS ACCOMPANYING THE PASSAGE OF DISTURBANCES THRU THE UPPER
LAKES MAY CAUSE HOLES TO OPEN IN THE ICE FROM TIME TO TIME...A
CONTINUED DOMINANCE OF ARCTIC AIR WILL MAINTAIN AN OVERALL EXTENSIVE
ICE COVER.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...KEC
AVIATION...ROLFSON
MARINE...KC
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1202 PM EST FRI FEB 27 2015
.AVIATION...
VERY DRY AIRMASS IN PLACE...BUT DEVELOPING LIGHT LOW LEVEL SOUTHWEST
FLOW IS ALLOWING LAKE INDUCED CLOUDS FROM LAKE MICHIGAN TO ADVECT
EASTWARD...AND IT APPEARS MBS WILL HAVE TO DEAL WITH THE LOW
VFR/BORDERLINE MVFR CEILINGS THIS AFTERNOON INTO THIS EVENING...WITH
DIMINISHING CHANCES FARTHER SOUTH...AS STRONG SURFACE HIGH ACROSS
THE NORTHERN OHIO VALLEY SHOULD ASSURE CLEAR SKIES TONIGHT ACROSS
THE DETROIT TAFS WITH NEARLY CALM WINDS. MOSTLY CLEAR SKIES WILL
PERSIST INTO TOMORROW...WITH JUST INCREASING MID/HIGH CLOUDS LATE
IN THE DAY.
//DTW THRESHOLD PROBABILITIES...
* LOW CONFIDENCE IN CEILING BELOW 5000 FT THIS AFTERNOON.
&&
.PREV DISCUSSION...ISSUED 846 AM EST FRI FEB 27 2015
UPDATE...
ANOTHER RECORD SETTING COLD MORNING AS ALL THREE CLIMATE SITES
BROKE OR TIED THEIR RESPECTIVE DAILY RECORDS.
FNT LOW WAS AT LEAST -17 F (UNABLE TO DIAL IN TO GET FINAL VALUE).
SAGINAW LOW WAS -9 AT 707 AM.
DETROIT TIED RECORD LOW...WITH -4 F AT 717 AM.
12Z DTX SOUNDING INDICATED A 925 MB TEMP OF -19 C...AND WITH THE
COLD START AND SOME LAKE CLOUDS EXPECTED TO PUSH EAST THIS
AFTERNOON (SEE RUC13 925 MB RH) UNDER LIGHT WESTERLY
FLOW...ESPECIALLY NORTHERN AREAS...MAXES WILL PROBABLY ONLY TOP
OUT IN THE MID TEENS...ON THE LOWER END OF THE GOING FORECAST.
PREV DISCUSSION...ISSUED 358 AM EST FRI FEB 27 2015
SHORT TERM...TODAY AND TONIGHT
RECORD LOWS FOR FEB 27
DETROIT AREA: -4 (1934)
FLINT AREA: -14 (1994)
SAGINAW: -8 (1934)
ANOTHER COLD MORNING ACROSS SOUTHEASTERN MICHIGAN WITH AN ARCTIC
SURFACE RIDGE LOCKED IN OVERHEAD. NIL WIND AND CLEAR SKIES HAS LED
TO FAVORABLE RADIATIVE COOLING CONDITIONS. SURFACE TEMPERATURES
CURRENTLY RANGE FROM 0 TO 10 DEGREES BELOW ZERO AS OF 3AM. WITH A
LACK OF LOW CLOUD DISCERNIBLE IN IR IMAGERY...EXPECTATIONS ARE FOR
SURFACE TEMPERATURES TO CONTINUE TO BOTTOM OUT BEFORE SUNRISE WITH
MANY RURAL LOCATIONS REACHING 10 TO 20 DEGREES BELOW ZERO. WITH A
DECOUPLED SURFACE LAYER...WILL HONOR THE DECISION OF PRIOR SHIFTS
AND NOT ISSUE A WIND CHILL ADVISORY.
COLDEST MIDLEVEL TEMPERATURES PUSHING OUT OF THE STATE TODAY IN
COMBINATION WITH AN SURFACE ANTICYCLONE PUSHING INTO PORTIONS OF
OHIO WILL ALLOW WIND DIRECTIONS OVER SOUTHEASTERN MICHIGAN TO MAKE A
CONCERTED MOVE TO SOUTHWESTERLY. ENHANCED MOISTURE AND LAKE MICHIGAN
CLOUD DEBRIS IS PROGGED TO STREAM EASTWARD WITH TIME...SHOWN TO
SLIDE THROUGH PORTIONS OF THE CWA BY THIS AFTERNOON AND INTO THE
EARLY EVENING. RAP SOUNDINGS SUGGEST THERE WILL BE A CONSIDERABLE
DIURNAL COMPONENT TO ANY SKY COVER. WIND TRAJECTORIES POINT TO THE
NORTHERN CWA/SAGAINAW VALLEY AS THE MORE FAVORABLE LOCATION FOR
CLOUDS. WITH SUN...SHADED A DEGREE OR TWO HIGHER THAN MOS GUIDANCE
FOR HIGHS.
SURFACE HIGH PRESSURE PUSHING THROUGH INDIANA AND OHIO WILL SET
ANOTHER NIGHT UP FOR CALM WINDS ACROSS THE SOUTHERN HALF OF THE CWA.
LOWERED MINS FOR AREAS SOUTH OF DETROIT. OTHERWISE...A PRESSURE
GRADIENT IN PLACE OVER THE TRI CITIES/NORTHERN THUMB AND SOME
POTENTIAL FOR LINGERING CLOUDS LIMITS THE TEMPERATURE FALL POTENTIAL
FOR TONIGHT.
LONG TERM...
COLD AIRMASS WILL REMAIN IN PLACE INTO EARLY THIS WEEKEND ALTHOUGH
TEMPERATURES WILL MODERATE EVER SO SLIGHTLY AS THE LATEST ARCTIC
HIGH PRESSURE SHIFTS TO THE EAST OF THE AREA SATURDAY NIGHT. HIGHS
ON SATURDAY WILL CLIMB TO AROUND 20F WITH LOWS THAT NIGHT HOLDING
INTO THE SINGLE DIGITS TO NEAR 10F AS BOTH THE COLDEST AIR SHIFTS
EAST AND EXPANDING CLOUD COVER WORKS INTO THE AREA WITH THE APPROACH
OF A LOW PRESSURE SYSTEM.
00Z MODEL RUNS...SAVE THE NAM12...BASICALLY SUPPORT THE PREVIOUS
FORECAST AS ROUGHLY 1 TO 2 INCHES OF SNOW FALL FROM THE I-69
CORRIDOR NORTH LATE SATURDAY NIGHT INTO EARLY SUNDAY EVENING WITH 2
TO 3 INCHES SOUTH OF THAT INTO METRO DETROIT AS H7 SPECIFIC HUMIDITY
CLIMBS TO AROUND 2 G/KG ALONG THE M-59 CORRIDOR. GIVEN THE
RELATIVELY HIGH SNOW TO LIQUID RATIOS EXPECTED WITH THE COLD AIRMASS
IN PLACE...15:1 OR A BIT MORE...WOULD NOT BE SURPRISED TO SEE UP TO
4 INCHES FROM THE I-94 CORRIDOR SOUTHWARD.
TEMPERATURES WILL EDGE BACK DOWN EARLY NEXT WEEK...BUT TO MUCH MORE
REASONABLE LEVELS THAN THE PAST SEVERAL WEEKS AS HIGHS MONDAY REACH
THE MID/UPPER 20S AND LOWS HOLD IN THE TEENS SUNDAY AND MONDAY NIGHT.
THE NEXT LOW PRESSURE SYSTEM APPEARS TO BE SHAPING UP TO BE A
STRONGER SYSTEM THAN THE WEEKEND EVENT...WITH A TRACK THAT WOULD
SUPPORT A WIDE VARIETY OF PRECIPITATION ACROSS THE CWA ON TUESDAY
WITH PRIMARILY SNOW OVER THE NORTHERN CWA AND SNOW CHANGING TO A MIX
AND THEN EVENTUALLY RAIN FURTHER SOUTH. WITH THE EVENTUAL TRACK AND
STRENGTH OF THIS SYSTEM STILL IN DOUBT...WILL FORGO ANY SIGNIFICANT
DETAILS AT THIS TIME...OTHER THAN TO INCLUDE SOME MENTION OF
SLEET...FREEZING RAIN AND RAIN AS 00Z RUNS OF THE GFS...CMC AND
ECMWF DO NOT SUPPORT AN ALL SNOW EVENT FOR THE ENTIRE CWA.
MARINE...
HIGH PRESSURE WILL BE BUILD FROM THE MID MISSISSIPPI VALLEY TODAY
THROUGH THE OHIO VALLEY ON SATURDAY. MODEST SOUTHWEST RETURN FLOW
WILL DEVELOP AROUND THIS HIGH OVER THE CENTRAL GREAT LAKES. CENTRAL
SECTIONS OF LAKE HURON WILL MOST LIKELY SEE WINDS INCREASE INTO THE
15 TO 20 KNOT RANGE. OTHERWISE...WINDS WILL REMAIN ON THE LIGHT SIDE
AS THIS SOUTHWEST PRESSURE GRADIENT WEAKENS LATE IN THE WEEKEND AS A
WEAK LOW PRESSURE SYSTEM LIFTS INTO THE REGION. EVEN THE RETURN OF
COLD NORTHWEST FLOW IN THE WAKE OF THE ATTENDING COLD FRONT WILL BE
LIMITED TO 25 KNOT GUSTS OR LESS OVER MUCH OF LAKE HURON.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&
$$
AVIATION.....SF
UPDATE.......SF
SHORT TERM...CB
LONG TERM....DG
MARINE.......DG
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
332 PM MST FRI FEB 27 2015
.SYNOPSIS...
AN UNSETTLED WEATHER PATTERN CONTINUES OVER NORTHERN AND CENTRAL
NEW MEXICO AS A SERIES OF STORM SYSTEMS PUSH OVER THE REGION. AS
ONE UPPER LEVEL DISTURBANCE DEPARTED THE STATE TO THE EAST THIS
MORNING...ANOTHER ONE IS CURRENTLY ARRIVING FROM THE WEST.
ADDITIONAL SNOW ACCUMULATIONS ARE EXPECTED THIS EVENING AND
OVERNIGHT...PRIMARILY IN NORTHWESTERN TO CENTRAL AND NORTH CENTRAL
PARTS OF NEW MEXICO. INTO SATURDAY AND SUNDAY...ANOTHER POTENT
DISTURBANCE WILL DIVE INTO CALIFORNIA BEFORE SLOWLY SPREADING OVER
NEW MEXICO. A PROLONGED PERIOD OF HIGH ELEVATION SNOW IS EXPECTED
OVER NORTH CENTRAL TO NORTHWESTERN NEW MEXICO
SATURDAY...SUNDAY...AND INTO MONDAY AND TUESDAY. THE HIGHEST SNOW
TOTALS WILL BE FOUND IN THE SAN JUAN OR TUSAS MOUNTAINS NEAR THE
COLORADO BORDER WHERE AN ADDITIONAL ONE TO TWO FEET OF SNOW COULD
ACCUMULATE...PRIMARILY IN THE HIGHER ELEVATIONS ABOVE EIGHT
THOUSAND FEET. RAIN WILL FALL IN LOWER ELEVATIONS DURING THIS
WEEKEND TO EARLY NEXT WEEK PERIOD.
&&
.DISCUSSION...IT`S ANOTHER BUSY AND CHALLENGING FORECAST DAY IN
THE MIDDLE OF A BARRAGE OF UPPER LEVEL DISTURBANCES. NOT MUCH OF A
RESPITE OR LULL IN THE PRECIPITATION WAS OBSERVED THIS MORNING
BEFORE THE NEXT UPSTREAM SYSTEM STARTED SPREADING MORE BATCHES OF
SNOW INTO WETSERN NM. THIS LATTER DISTURBANCE IS A BIT MORE SUBTLE
LOOKING ON WATER VAPOR IMAGERY COMPARED TO ITS
PREDECESSOR...HOWEVER JET DYNAMICS ARE UNDERWAY AND STRENGTHENING
WITH LOTS OF DIVERGENCE ALOFT BEING DEPICTED BY FORECAST MODELS.
THIS SEEMS TO BE QUICKLY COMING TO FRUITION GIVEN LIGHT SNOW THAT
HAS ALREADY ENSUED AND STARTED AGAIN IN CENTRAL TO WESTERN ZONES.
FORECAST MODELS KEEP THIS DIVERGENCE ALOFT PEGGED OVER THE
NORTHWESTERN QUADRANT OF NM TONIGHT...AND QPF IS GENEROUSLY
PAINTED BENEATH. HRRR MODEL IS ALSO QUITE GENEROUS WITH THIS TREND
WITH A FEW MESOSCALE BANDS OF SNOW BEING DEPICTED. THUS...FELT
PRUDENT TO SPATIALLY AND TEMPORALLY EXTEND ADVISORIES/WARNING
WESTWARD AND LONGER RESPECTIVELY. THESE AMENDMENTS WERE MADE AT
NOON AND WILL HOLD FOR NOW.
INTO SATURDAY THE DIVERGENCE SLOWLY DECREASES IN INTENSITY OVER NM
AND THE FLOW ALOFT BEGINS BACKING MORE SOUTHWESTERLY AS A LOW
TAKES SHAPE AND DIVES INTO CA. THIS SHOULD BEGIN A REDUCTION IN
THE COVERAGE OF PRECIPITATION IN SOME LOWER ELEVATION
AREAS...REDUCTION BEING RELATIVE...WHILE OROGRAPHICS BECOME THE
MORE DOMINANT FORCING MECHANISM FOR THE HIGHER TERRAIN. ELEVATIONS
BELOW 7000 FEET WOULD ALSO OBSERVE A QUICK WARMING TREND AS WARM
AIR ADVECTION BEGINS IN THE SOUTHWESTERLY FLOW. THE FORECAST
MODELS MAY BE A BIT TOO HIGH WITH MAX TEMPERATURE GUIDANCE ON THIS
THOUGH...AS THE CLOUD COVER MAY BE SLOW TO ERODE...STUNTING THE
WARMING MORE THAN WHAT IS ADVERTISED BY MODELS. HAVE BUILT IN A
QUICK CHANGEOVER TO RAIN IN THESE LOWER ELEVATIONS BY LATE MORNING
AND INTO THE AFTERNOON...BUT THIS COULD BE A BIT PREMATURE AND
WILL NEED TO BE CLOSELY MONITORED. PRECIPITATION COULD ALSO BEGIN
TO TAKE ON A SHOWERY OR CONVECTIVE NATURE TO IT AS MODELS HAVE
LIFTED INDICES OF 0 TO -1C PROGGED OVER SOME NORTH CENTRAL TO
NORTHWESTERN ZONES SATURDAY AFTERNOON. THIS WOULD ONLY ADD TO SNOW
RATES IN THE HIGHER TERRAIN. THE WINTER HIGHLIGHTS/STATEMENTS IN
THE NORTHWESTERN ZONES DROP OFF SATURDAY MORNING...BUT MAY NEED TO
BE EXTENDED FOR AFOREMENTIONED REASONINGS.
THE PRECIPITATION REALLY FOCUSES TOWARD THE NORTHWESTERN THIRD OF
THE FORECAST AREA INTO SATURDAY NIGHT AND SUNDAY WITH FLOW
CONTINUING TO BACK SLIGHTLY MORE WHILE SPEEDS ALOFT INCREASE. THIS
WILL KEEP STEADY OROGRAPHIC FORCING OVER THE NORTH CENTRAL TO
NORTHWESTERN MOUNTAINS WITH SOME PRONOUNCED PRECIPITATION SHADOWS
DOWNWIND OR NORTHEAST OF CHUSKAS AND OTHER TOPOGRAPHICAL BARRIERS.
THE SOUTHWESTERLY FLOW ALOFT AND RISING PRESSURE HEIGHTS WILL ALSO
KEEP THE WARMER AIR ADVECTING THIS WAY...AND SATURDAY NIGHT`S LOW
TEMPERATURES WILL BE 10 TO 15 DEGREES WARMER THAN TONIGHT`S
READINGS WHILE SUNDAY`S HIGHS RISE ANOTHER 5 TO 15 DEGREES ABOVE
SATURDAY`S HIGHS. THIS WARMING TREND WILL SHIFT SNOWFALL
ACCUMULATIONS UPWARD TO 7500 TO 8500 FEET SUNDAY AFTERNOON. WHILE
THIS WILL LIMIT THE SPATIAL AREA OF SNOWFALL ACCUMULATIONS...THE
PEAKS ABOVE THIS THRESHOLD WILL STILL SEE REMARKABLE SNOW
AMOUNTS...LIKELY ONE TO THREE FEET ON MANY PEAKS ABOVE 8500 FEET
AND CLOSER TO FOUR FEET NEAR THE CO/NM BORDER ABOVE 10000 FEET.
RUNOFF AND SNOW MELT AT LOWER ELEVATIONS WILL ALSO NEED TO BE
MONITORED CLOSELY ON SUNDAY...PERHAPS CREATING HYDROLOGY ISSUES.
AND THE THREAT FOR ACCUMULATION STILL WON`T END THROUGH MONDAY AS
THE UPPER LOW ROUNDS SOUTHERN CA AND DRIVES A PACIFIC FRONT CLOSER
TO NM...EVENTUALLY CROSSING INTO OUR FORECAST AREA MONDAY NIGHT.
THIS FRONTOGENETICAL FORCING IN ITSELF WILL ALSO INDUCE A HEALTHY
SLUG OF PRECIPITATION...POSSIBLY ENHANCED BY A SUBTROPICAL
MOISTURE TAP. THEN A KICKER SHORT WAVE TROUGH WILL DIG ON THE BACK
SIDE OF THIS BEFORE TURNING INTO OLD MEXICO TUESDAY AND EARLY
WEDNESDAY. FINALLY THE CABOOSE IN THE TRAIN OF STORM SPILLS
SOUTHWARD IN STRONG MERIDIONAL FLOW ON WEDNESDAY...UNLOCKING THE
DOOR TO SOME VERY COLD CONTINENTAL POLAR AIR. ONCE THIS SYSTEM
PASSES...A WELCOME DRIER PATTERN SHOULD FOLLOW INTO THURSDAY OF
NEXT WEEK.
52
&&
.FIRE WEATHER...
AN ACTIVE WEATHER PATTERN WILL PERSIST THROUGH THE MIDDLE OF NEXT
WEEK. MOIST WESTERLY FLOW WILL CONTINUE OVER NORTHERN AND CENTRAL
NEW MEXICO TONIGHT AND SATURDAY...ALLOWING WEST FACING HIGHER
TERRAIN LOCATIONS...ESPECIALLY FROM THE WEST CENTRAL TO THE NORTH
CENTRAL...TO CONTINUE PICKING UP SNOW. THE WINDS ALOFT TRANSITION TO
SOUTHWEST SUNDAY INTO MONDAY AS AN UPPER LOW/TROUGH DIG INTO SOCAL
AND ARIZONA. TEMPERATURES WILL WARM IN ADVANCE OF THE LOW...ALLOWING
SNOW LEVELS TO GRADUALLY RISE FROM WHAT THEY ARE THIS AFTERNOON.
SOME COOLER AIR MAY ENTER THE EASTERN PLAINS SUNDAY...BOTH ECMWF AND
GFS AGREE...BUT LOOKS LIKE IT MERELY RETARDS WARMING IN THE PLAINS
FOR ANOTHER DAY RATHER THAN BRINGS ANOTHER SURGE OF MUCH COLDER AIR.
A SPLIT FLOW PATTERN DOMINATES EARLY TO MID NEXT WEEK...PERMITTING A
MUCH COLDER AND DRIER AIR MASS TO SURGE INTO THE EASTERN PLAINS
TUESDAY NIGHT/WEDNESDAY. THIS LOOKS TO BE THE LAST GASP FOR THE
ACTIVE WEATHER AT LEAST FOR THE REST OF NEXT WEEK.
THROUGH EARLY NEXT WEEK...HEAVY SNOW ACCUMULATIONS ARE LIKELY FOR
THE NORTHERN MOUNTAINS. ALTHOUGH SNOW LEVELS ARE FORECAST TO RISE
SUNDAY INTO MONDAY...SOME OF THE HIGHER NORTHERN/WESTERN TERRAIN
WILL CONTINUE TO RECEIVE SNOW...AND SNOW LEVELS OVERALL FALL AGAIN
TUESDAY AS THE UPPER LOW/TROUGH MOVE OVERHEAD AND TO OUR SOUTH.
HIGH TEMPERATURES THROUGH THE MIDDLE OF NEXT WEEK WILL REMAIN BELOW
AVERAGE. VENT RATES WILL BE POOR IN THE EAST SATURDAY AND SUNDAY BUT
GOOD TO EXCELLENT OVER MOST OF THE WEST CENTRAL AND SOUTHWEST DUE TO
INCREASING WINDS AND MIXING HEIGHTS. VENT RATES OVERALL NEXT MONDAY
AND TUESDAY WILL BE EXCELLENT THEN WORSEN SOMEWHAT WEDNESDAY.
EXCELLENT RH RECOVERIES EXPECTED THROUGH THE PERIOD ALTHOUGH MIN RH
VALUES TREND MUCH LOWER WEDNESDAY INTO THURSDAY.
&&
.AVIATION...
18Z TAF CYCLE
MTS OBSCURED IN WDSPRD MVFR TO IFR CIGS/VSBYS IN SNOW AND FOG
ALTHOUGH A MIX OF RAIN AND SNOW POSSIBLE LOWER ELEVATIONS WEST OF
THE CONTDVD BEFORE 28/00Z. SNOW TO INCREASE FROM THE CHUSKA MTS
EAST AND NORTHEAST TO THE SANGRE DE CRISTO MTS AND POSSIBLY AS FAR
SOUTH INTO THE ABQ METRO AFT 28/00Z. UPPER JET TO REMAIN ORIENTED
FROM NW TO SE OVER NEW MEXICO THRU 28/12Z AS SURFACE HIGH PRESSURE
OVER ERN NM BEGINS TO WEAKEN.
&&
.PRELIMINARY POINT TEMPS/POPS...
FARMINGTON...................... 30 46 33 46 / 80 70 60 60
DULCE........................... 22 37 28 42 / 90 80 80 90
CUBA............................ 24 38 30 45 / 90 70 60 80
GALLUP.......................... 32 47 36 50 / 60 70 70 80
EL MORRO........................ 29 47 35 51 / 50 50 60 70
GRANTS.......................... 27 50 32 54 / 60 40 40 60
QUEMADO......................... 31 50 38 53 / 30 20 40 40
GLENWOOD........................ 37 61 42 62 / 10 30 20 50
CHAMA........................... 19 34 26 40 / 90 80 80 90
LOS ALAMOS...................... 22 37 33 46 / 70 60 60 70
PECOS........................... 15 36 31 44 / 80 50 60 50
CERRO/QUESTA.................... 17 34 27 42 / 90 60 70 70
RED RIVER....................... 17 28 26 37 / 90 70 70 70
ANGEL FIRE...................... 14 33 23 40 / 90 60 70 60
TAOS............................ 20 36 31 45 / 80 60 60 60
MORA............................ 14 37 31 44 / 60 40 60 50
ESPANOLA........................ 22 43 32 52 / 60 40 40 50
SANTA FE........................ 20 39 33 48 / 70 50 50 50
SANTA FE AIRPORT................ 20 41 32 50 / 60 40 50 50
ALBUQUERQUE FOOTHILLS........... 26 48 36 57 / 60 40 40 30
ALBUQUERQUE HEIGHTS............. 27 50 37 60 / 50 30 30 30
ALBUQUERQUE VALLEY.............. 25 52 34 62 / 50 30 30 30
ALBUQUERQUE WEST MESA........... 25 50 36 61 / 60 30 40 40
LOS LUNAS....................... 28 53 36 62 / 30 20 20 20
RIO RANCHO...................... 27 48 36 58 / 60 30 40 40
SOCORRO......................... 31 56 39 64 / 20 10 10 10
SANDIA PARK/CEDAR CREST......... 20 40 34 49 / 60 40 50 40
TIJERAS......................... 24 45 35 55 / 60 40 50 30
MORIARTY/ESTANCIA............... 17 43 31 56 / 60 30 40 20
CLINES CORNERS.................. 15 37 30 48 / 60 30 40 20
GRAN QUIVIRA.................... 21 45 36 55 / 40 20 20 20
CARRIZOZO....................... 28 53 40 60 / 20 10 10 10
RUIDOSO......................... 26 49 36 57 / 30 20 10 10
CAPULIN......................... 10 31 24 33 / 50 30 30 40
RATON........................... 11 33 23 38 / 60 30 40 40
SPRINGER........................ 12 35 24 41 / 60 30 30 30
LAS VEGAS....................... 12 35 29 43 / 60 40 40 30
CLAYTON......................... 11 32 22 30 / 50 20 20 30
ROY............................. 13 31 26 39 / 50 30 30 20
CONCHAS......................... 18 36 29 46 / 40 20 20 20
SANTA ROSA...................... 18 36 30 52 / 40 20 20 10
TUCUMCARI....................... 17 38 30 46 / 30 20 10 10
CLOVIS.......................... 16 39 30 54 / 30 20 10 5
PORTALES........................ 17 41 31 58 / 30 20 10 0
FORT SUMNER..................... 19 40 31 54 / 30 20 10 5
ROSWELL......................... 23 49 34 65 / 30 10 10 0
PICACHO......................... 22 48 33 64 / 30 10 10 0
ELK............................. 23 52 37 63 / 20 10 10 5
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL 8 AM MST SATURDAY FOR THE FOLLOWING
ZONES...NMZ502>504-516-518-519-521.
WINTER WEATHER ADVISORY UNTIL 8 AM MST SATURDAY FOR THE FOLLOWING
ZONES...NMZ501-505>507-517.
WINTER STORM WARNING UNTIL 4 PM MST SUNDAY FOR THE FOLLOWING
ZONES...NMZ510>515-527.
&&
$$
52
AREA FORECAST DISCUSSION...UPDATED
NWS MEMPHIS TN
1154 AM CST FRI FEB 27 2015
.UPDATE...
UPDATED TO INCLUDE THE 18Z AVIATION DISCUSSION BELOW.
JCL
&&
.DISCUSSION... /ISSUED 1041 AM CST FRI FEB 27 2015/
WATER VAPOR SATELLITE/WSR-88D VAD WIND PROFILE TRENDS INDICATE A
SUBTLE MID-LEVEL SHORTWAVE TROUGH LOCATED ACROSS OKLAHOMA LATE
THIS MORNING. THIS IS PRODUCING SOME SNOW NEAR THE TEXAS/OKLAHOMA
PANHANDLE. MEANWHILE...ACROSS THE MID SOUTH SUNNY TO MOSTLY SUNNY
SKIES ARE PREVAILING WITH TEMPERATURES AS OF 10 AM CST IN THE
TEENS ACROSS THE NORTHERN THIRD OF THE MID SOUTH AND 20S ACROSS
THE REMAINDER OF THE FORECAST AREA.
LATEST SHORT TERM MODEL TRENDS INDICATE THIS PRECIPITATION MAY
ENTER PORTIONS OF THE MIDDLE AND LOWER MISSISSIPPI VALLEYS LATER
THIS AFTERNOON INTO TONIGHT. HOWEVER...CONFIDENCE REMAINS LOW
WITH ANY PRECIPITATION ENTERING EXTREME NORTHEAST ARKANSAS.
THUS...WILL REMOVE THE POPS IN FOR LATE AFTERNOON/THIS EVENING
UNTIL TRENDS SUGGEST OTHERWISE.
WILL MAKE SOME ADJUSTMENTS TO SKY COVER AND ANY OTHER ELEMENTS AS
NEEDED TO ACCOUNT FOR CURRENT SHORT TERM TRENDS.
UPDATED GRIDS WILL BE AVAILABLE SHORTLY.
CJC
PREV DISCUSSION... /ISSUED 714 AM CST FRI FEB 27 2015/
UPDATED FORECAST TO ADD A SMALL CHANCE OF LIGHT SNOW ACROSS NE AR
LATER TODAY INTO TONIGHT. LATEST GUIDANCE SUGGESTS THAT SOME OF
THE SNOW OVER THE SOUTHERN PLAINS MAY REACH NW PARTS OF THE
MIDSOUTH. 11Z HRRR INDICATES THIS POSSIBILITY AND MAV MOS POPS
ALSO HINT AT IT.
SJM
PREV DISCUSSION... /ISSUED 418 AM CST FRI FEB 27 2015/
CURRENTLY...ARCTIC HIGH PRESSURE IS SETTLING ACROSS THE MID
MISSISSIPPI VALLEY. STRONG COLD AIR ADVECTION CONTINUES ACROSS THE
AREA WITH SCT-BKN LOW CLOUDS AND A FEW FLURRIES. TEMPS RANGE FROM
THE UPPER TEENS NORTH TO UPPER 20S SOUTH WITH WIND CHILLS IN THE
SINGLE DIGITS NORTH TO TEENS SOUTH.
TODAY...ARCTIC HIGH PRESSURE BEGINS TO SLIDE FROM THE MIDDLE
MISSISSIPPI VALLEY INTO THE OHIO VALLEY. A WEAK UPPER LEVEL
DISTURBANCE WILL GENERATE SOME LIGHT SNOW OVER WRN OKLAHOMA AND
THE RED RIVER VALLEY THIS AFTERNOON BUT THIS AREA IS EXPECTED TO
DISSIPATE AS IT MOVES ACROSS ARKANSAS. WOULD NOT BE SURPRISED TO
SEE A FEW FLAKES ACROSS NE ARKANSAS BUT AT THIS POINT NOT
CONFIDENT ENOUGH TO INTRODUCE INTO THE FORECAST. SHOULD SEE SOME
SUN THIS MORNING FOLLOWED BY AND INCREASE IN MIDDLE AND HIGH
CLOUDS THIS AFTERNOON. EXPECT A VERY COLD DAY WITH HIGHS IN THE
MID 20S NORTH TO MID 30S SOUTH. THE AVERAGE HIGH IN MEMPHIS IS
58F.
TONIGHT...HIGH PRESSURE REMAINS IN CONTROL. EXPECT A GOOD DEAL OF
MID AND HIGH CLOUDINESS SO TEMPS WILL NOT GET RIDICULOUSLY
COLD...JUST VERY COLD. BY MORNING LOW TEMPS WILL RANGE FROM
20-25F.
SATURDAY...ARCTIC HIGH MOVES OFF TO THE MID ATLANTIC AND SLOWLY
LOOSES ITS GRIP ON THE MIDSOUTH. SHOULD SEE AT LEAST SOME SUN WITH
TEMPS CLIMBING INTO THE UPPER 30S TO UPPER 40S. BREAK OUT THE LAWN
CHAIRS.
SATURDAY NIGHT THROUGH MONDAY...AN WEAK UPPER LEVEL DISTURBANCE
MOVING ACROSS OK/MO WILL RESULT IN A SLIGHT CHANCE OF RAIN ACROSS
THE AREA SATURDAY NIGHT...PERHAPS A LITTLE FREEZING RAIN OVER NE
AR. BY SUNDAY A MORE IMPRESSIVE MID LEVEL TROUGH MOVING THROUGH
THE GREAT LAKES WILL PUSH A COLD FRONT INTO THE MIDSOUTH WITH RAIN
CHANCES INCREASING SUNDAY INTO MONDAY. TEMPS WILL WARM INTO THE
50S MOST PLACES AHEAD OF THE FRONT ON SUNDAY. ON MONDAY TEMPS WILL
SLIGHTLY COOLER WITH HIGH PRESSURE BUILDING TO THE NORTH. PRECIP
CHANCE SHOULD TAIL OFF ACROSS THE NORTH ON MONDAY.
MONDAY NIGHT INTO WEDNESDAY...MAJOR DIFFERENCES IN TIMING BETWEEN
GFS AND ECWMF. A MAJOR UPPER LEVEL TROF WILL DEVELOP OVER THE
WESTERN U.S. EARLY IN THE WEEK AND THERE ARE DIFFERENCES BETWEEN
THE MODELS AS TO WHEN IT WILL PUSH INTO THE MIDDLE OF THE COUNTRY.
THE GFS IS MUCH FASTER...PUSHING AN ACTIVE WARM FRONT NORTH EARLY
TUESDAY WITH SURFACE LOW PRESSURE MOVING THROUGH THE MIDDLE
MISSISSIPPI VALLEY THEN A COLD FRONT WILL MOVE THROUGH TUESDAY
NIGHT. THE ECMWF PUSHES THE WARM FRONT THROUGH LATER TUESDAY AND
THE COLD FRONT THROUGH DURING THE DAY ON WEDNESDAY. AT THIS POINT
WILL TAKE THE COMPROMISE APPROACH AND SPREAD FAIRLY HIGH POPS
THROUGH THE PERIOD. AHEAD OF THE COLD FRONT SURFACE DEWPOINTS
CLIMB INTO THE 60S AND THERE ARE INDICATIONS THAT SOME INSTABILITY
WILL BE PRESENT SO WILL NEED TO WATCH THE TUESDAY NIGHT-WEDNESDAY
PERIOD FOR SEVERE POTENTIAL. EXPECT HIGHS IN THE 60S AND SOME 70S
TUESDAY. HIGHS ON WEDNESDAY WILL BE HIGHLY DEPENDENT ON WHETHER
THE FRONT HAS GONE THROUGH.
WEDNESDAY NIGHT THROUGH THURSDAY...PRECIP WRAPPING UP AND MUCH
COLDER. THE GFS HAS A MUCH COLDER BLAST BEHIND THIS SYSTEM BUT
WILL TEMPER THAT GIVEN THE ECMWF SOLUTION. NONETHELESS BELOW
NORMAL TEMPS EXPECTED ONCE AGAIN FOR THE END OF THE WEEK.
SJM
&&
.AVIATION...
18Z TAF CYCLE (27/18Z-28/18Z)
OCCASIONAL MVFR CEILINGS WILL OCCUR AT KMEM UNTIL 19Z...OTHERWISE
VFR CONDITIONS WILL OCCUR AT THE TAF SITES THROUGH THE PERIOD.
WINDS THIS AFTERNOON NE WINDS 10-12 KTS. WINDS TONIGHT NE 8-11
KTS. WINDS SATURDAY MORNING NE-E 7-8 KTS.
JCL
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
1041 AM CST FRI FEB 27 2015
.DISCUSSION...WATER VAPOR SATELLITE/WSR-88D VAD WIND PROFILE
TRENDS INDICATE A SUBTLE MID-LEVEL SHORTWAVE TROUGH LOCATED ACROSS
OKLAHOMA LATE THIS MORNING. THIS IS PRODUCING SOME SNOW NEAR THE
TEXAS/OKLAHOMA PANHANDLE. MEANWHILE...ACROSS THE MID SOUTH SUNNY
TO MOSTLY SUNNY SKIES ARE PREVAILING WITH TEMPERATURES AS OF 10 AM
CST IN THE TEENS ACROSS THE NORTHERN THIRD OF THE MID SOUTH AND
20S ACROSS THE REMAINDER OF THE FORECAST AREA.
LATEST SHORT TERM MODEL TRENDS INDICATE THIS PRECIPITATION MAY
ENTER PORTIONS OF THE MIDDLE AND LOWER MISSISSIPPI VALLEYS LATER
THIS AFTERNOON INTO TONIGHT. HOWEVER...CONFIDENCE REMAINS LOW
WITH ANY PRECIPITATION ENTERING EXTREME NORTHEAST ARKANSAS.
THUS...WILL REMOVE THE POPS IN FOR LATE AFTERNOON/THIS EVENING
UNTIL TRENDS SUGGEST OTHERWISE.
WILL MAKE SOME ADJUSTMENTS TO SKY COVER AND ANY OTHER ELEMENTS AS
NEEDED TO ACCOUNT FOR CURRENT SHORT TERM TRENDS.
UPDATED GRIDS WILL BE AVAILABLE SHORTLY.
CJC
&&
.PREV DISCUSSION... /ISSUED 714 AM CST FRI FEB 27 2015/
DISCUSSION...
UPDATED FORECAST TO ADD A SMALL CHANCE OF LIGHT SNOW ACROSS NE AR
LATER TODAY INTO TONIGHT. LATEST GUIDANCE SUGGESTS THAT SOME OF
THE SNOW OVER THE SOUTHERN PLAINS MAY REACH NW PARTS OF THE
MIDSOUTH. 11Z HRRR INDICATES THIS POSSIBILITY AND MAV MOS POPS
ALSO HINT AT IT.
SJM
PREV DISCUSSION... /ISSUED 418 AM CST FRI FEB 27 2015/
CURRENTLY...ARCTIC HIGH PRESSURE IS SETTLING ACROSS THE MID
MISSISSIPPI VALLEY. STRONG COLD AIR ADVECTION CONTINUES ACROSS THE
AREA WITH SCT-BKN LOW CLOUDS AND A FEW FLURRIES. TEMPS RANGE FROM
THE UPPER TEENS NORTH TO UPPER 20S SOUTH WITH WIND CHILLS IN THE
SINGLE DIGITS NORTH TO TEENS SOUTH.
TODAY...ARCTIC HIGH PRESSURE BEGINS TO SLIDE FROM THE MIDDLE
MISSISSIPPI VALLEY INTO THE OHIO VALLEY. A WEAK UPPER LEVEL
DISTURBANCE WILL GENERATE SOME LIGHT SNOW OVER WRN OKLAHOMA AND
THE RED RIVER VALLEY THIS AFTERNOON BUT THIS AREA IS EXPECTED TO
DISSIPATE AS IT MOVES ACROSS ARKANSAS. WOULD NOT BE SURPRISED TO
SEE A FEW FLAKES ACROSS NE ARKANSAS BUT AT THIS POINT NOT
CONFIDENT ENOUGH TO INTRODUCE INTO THE FORECAST. SHOULD SEE SOME
SUN THIS MORNING FOLLOWED BY AND INCREASE IN MIDDLE AND HIGH
CLOUDS THIS AFTERNOON. EXPECT A VERY COLD DAY WITH HIGHS IN THE
MID 20S NORTH TO MID 30S SOUTH. THE AVERAGE HIGH IN MEMPHIS IS
58F.
TONIGHT...HIGH PRESSURE REMAINS IN CONTROL. EXPECT A GOOD DEAL OF
MID AND HIGH CLOUDINESS SO TEMPS WILL NOT GET RIDICULOUSLY
COLD...JUST VERY COLD. BY MORNING LOW TEMPS WILL RANGE FROM
20-25F.
SATURDAY...ARCTIC HIGH MOVES OFF TO THE MID ATLANTIC AND SLOWLY
LOOSES ITS GRIP ON THE MIDSOUTH. SHOULD SEE AT LEAST SOME SUN WITH
TEMPS CLIMBING INTO THE UPPER 30S TO UPPER 40S. BREAK OUT THE LAWN
CHAIRS.
SATURDAY NIGHT THROUGH MONDAY...AN WEAK UPPER LEVEL DISTURBANCE
MOVING ACROSS OK/MO WILL RESULT IN A SLIGHT CHANCE OF RAIN ACROSS
THE AREA SATURDAY NIGHT...PERHAPS A LITTLE FREEZING RAIN OVER NE
AR. BY SUNDAY A MORE IMPRESSIVE MID LEVEL TROUGH MOVING THROUGH
THE GREAT LAKES WILL PUSH A COLD FRONT INTO THE MIDSOUTH WITH RAIN
CHANCES INCREASING SUNDAY INTO MONDAY. TEMPS WILL WARM INTO THE
50S MOST PLACES AHEAD OF THE FRONT ON SUNDAY. ON MONDAY TEMPS WILL
SLIGHTLY COOLER WITH HIGH PRESSURE BUILDING TO THE NORTH. PRECIP
CHANCE SHOULD TAIL OFF ACROSS THE NORTH ON MONDAY.
MONDAY NIGHT INTO WEDNESDAY...MAJOR DIFFERENCES IN TIMING BETWEEN
GFS AND ECWMF. A MAJOR UPPER LEVEL TROF WILL DEVELOP OVER THE
WESTERN U.S. EARLY IN THE WEEK AND THERE ARE DIFFERENCES BETWEEN
THE MODELS AS TO WHEN IT WILL PUSH INTO THE MIDDLE OF THE COUNTRY.
THE GFS IS MUCH FASTER...PUSHING AN ACTIVE WARM FRONT NORTH EARLY
TUESDAY WITH SURFACE LOW PRESSURE MOVING THROUGH THE MIDDLE
MISSISSIPPI VALLEY THEN A COLD FRONT WILL MOVE THROUGH TUESDAY
NIGHT. THE ECMWF PUSHES THE WARM FRONT THROUGH LATER TUESDAY AND
THE COLD FRONT THROUGH DURING THE DAY ON WEDNESDAY. AT THIS POINT
WILL TAKE THE COMPROMISE APPROACH AND SPREAD FAIRLY HIGH POPS
THROUGH THE PERIOD. AHEAD OF THE COLD FRONT SURFACE DEWPOINTS
CLIMB INTO THE 60S AND THERE ARE INDICATIONS THAT SOME INSTABILITY
WILL BE PRESENT SO WILL NEED TO WATCH THE TUESDAY NIGHT-WEDNESDAY
PERIOD FOR SEVERE POTENTIAL. EXPECT HIGHS IN THE 60S AND SOME 70S
TUESDAY. HIGHS ON WEDNESDAY WILL BE HIGHLY DEPENDENT ON WHETHER
THE FRONT HAS GONE THROUGH.
WEDNESDAY NIGHT THROUGH THURSDAY...PRECIP WRAPPING UP AND MUCH
COLDER. THE GFS HAS A MUCH COLDER BLAST BEHIND THIS SYSTEM BUT
WILL TEMPER THAT GIVEN THE ECMWF SOLUTION. NONETHELESS BELOW
NORMAL TEMPS EXPECTED ONCE AGAIN FOR THE END OF THE WEEK.
SJM
&&
.AVIATION...
12Z TAF CYCLE
MVFR CIGS WILL LINGER THIS MORNING AT TUP...OTHERWISE THE
TAF SITES WILL BE VFR THROUGH THE PERIOD. NORTH TO NORTHEAST
WINDS IN THE 10-15 KT RANGE WILL DIMINISH TO 6-9 KTS LATE.
JAB
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BROWNSVILLE TX
1151 AM CST FRI FEB 27 2015
.DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.
&&
.AVIATION...HIGH CLOUDS ARE EXPECTED TO DECREASE AS THE UPPER JET
SHIFTS DOWNSTREAM. COLD AIR BEHIND A COLD FRONT IS FILTERING INTO
THE WESTERN PORTION OF THE CWA THIS MORNING...AND THE ISENTROPIC
LIFT WILL SUPPORT LOWERING CEILINGS...WITH LIGHT RAIN AND DRIZZLE
STARTING TO MOVE INLAND. THIS RAIN WILL GRADUALLY BE ON THE INCREASE
DURING THE DAY. A VERY SHARP TEMPERATURE GRADIENT WITH A WARM AIR MASS
FROM HWY 77 EAST AND COLDER WEST OF 77 ASOCIATED TO THIS COLD FRONT.
AS THE COASTAL TROUGH STRENGTHENS THE WINDS SHIFT MORE NORTHERLY LATER
INTO TONIGHT. THIS TROUGH WILL EVENTUALLY BE LIFTED NORTHEAST WITH COLD
AIR MASS FROM THE WEST TAKING CONTROL AND FILTERING IN THROUGH THE AREA.
THE WINDS WILL BEGIN TO SHIFT NORTHWEST CLOSER TO MIDNIGHT AND WESTERLY
INTO SATURDAY.
&&
.PREV DISCUSSION... /ISSUED 1035 AM CST FRI FEB 27 2015/
DISCUSSION...THE COLD AIR CONTINUES TO MOVE SOUTH ACROSS
THE CWA ESPECIALLY TOWARDS THE WESTERN PORTION OF THE CWA.
THIS HAS SHIFTED WINDS MORE NORTHWEST KEEPING TEMPERATURES
COOLER THAN EXPECTED. KEPT A NORTH TO NORTHWEST FLOW ACROSS
THE AREA WITH A SHARP TEMPERATURE GRADIENT FROM WEST TO EAST.
LOWER HIGH TEMPERATURES A FEW DEGREES MORE TOWARDS THE WEST
AND WITH A EASTERLY FLOW DEVELOPING KEPT WARMER TEMPERATURES
IN THE MID 60S. CHANCE OF RAIN REMAINS THE SAME AND THERE ARE
NO OTHER CHANGES DONE TO THE FORECAST AT THIS TIME.
PREV DISCUSSION... /ISSUED 547 AM CST FRI FEB 27 2015/
DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.
AVIATION...HIGH CLOUDS ARE EXPECTED TO DECREASE AS THE UPPER JET
SHIFTS DOWNSTREAM. COLD AIR BEHIND A COLD FRONT IS FILTERING INTO
THE CWA THIS MORNING...AND THE ISENTROPIC LIFT WILL SUPPORT
LOWERING CEILINGS...WITH LIGHT RAIN AND DRIZZLE POSSIBLE LATER IN
THE DAY. LIGHT TO MODERATE NORTHEAST WINDS WILL BECOME VERY LIGHT
THIS EVE...BUT WILL THEN PICK UP AGAIN SLIGHTLY AFTER MIDNIGHT.
CEILINGS SHOULD LOWER TO MVFR BY MID MORNING AND THEN TO IFR LATER
TODAY. THE GUIDANCE VARIES A LITTLE FOR THIS EVENING...WITH THE
GFS KEEPING CEILINGS A CATEGORY HIGHER THAN THE NAM...BUT MVFR IS
THE MIDDLE GROUND FOR NOW.
&&
PREV DISCUSSION... /ISSUED 254 AM CST FRI FEB 27 2015/
SHORT TERM /NOW THROUGH SATURDAY/...A COLD FRONT IS WORKING ITS
WAY THROUGH THE CWA THIS MORNING...WITHOUT TOO MUCH FANFARE.
SOUTHERN EDGE AND RR QUAD OF AN UPPER JET STREAK RESULTED IN A
RIBBON OF UPPER CLOUDS STILL OVER THE SOUTHEASTERN CORNER OF THE
CWA BUT THAT SHOULD FADE TODAY AS THICKER LOW CLOUDS TAKE OVER.
LOW CLOUDS ARE THICKENING FROM WEST TO EAST. NORTHEAST WINDS THAT
WERE ALREADY IN PLACE ARE RECEIVING SOME REINFORCEMENT AND DEW
POINTS ARE DECREASING BEHIND THE FRONT. LOOKING FOR A
COOL...CLOUDY DAY ACROSS DEEP SOUTH TEXAS AND THE RGV TODAY WITH A
RANGE OF HIGH TEMPS FROM THE UPPER 40S FAR WEST AND NORTH TO THE
LOWER 60S FOR CAMERON AND WILLACY COUNTIES. LIGHT RAIN AND DRIZZLE
CHANCES WILL INCREASE LATER TODAY AND TONIGHT AS THE COOLER AIR
BECOMES ESTABLISHED. LOW TEMPS TONIGHT WILL BE MAINLY IN THE 40S
AND 50S WITH LIGHT WINDS AS HIGH PRESSURE SPREADS OVER THE AREA.
LOOKS LIKE THE HIGH PRESSURE WILL THEN SHIFT EAST IN SHORT ORDER.
WINDS WILL VEER TO EAST BY SATURDAY AND THE RETURN FLOW WILL
SUPPORT HIGH TEMPS IN THE 60S...THOUGH AMPLE CLOUD COVER WILL
CONTINUE AND A MID LEVEL FLOW THAT WILL BACK FROM WEST TO
SOUTHWEST WILL HELP ENSURE THAT OVERRUNNING PERSISTS.
LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...OVERRUNNING LIGHT
RAIN CHANCES ACROSS DEEP SOUTH TEXAS AND THE RGV WILL COME TO AN
END SUNDAY AS COASTAL TROUGHING WEAKENS AND A WARM FRONT LIFTS
NORTHWARD. WINDS BECOME SOUTHEASTERLY BY SUNDAY MORNING AND
MOISTURE DECREASES. COLD AIR IS SHUNTED NORTH AND EAST FOR THE
START OF THE WORK WEEK WITH 850MB TEMPERATURES RISING FROM 13C
SUNDAY MORNING TO 22C BY TUESDAY NIGHT. 700MB SOUTHWESTERLIES
SPREAD OVER THE AREA BEGINNING MONDAY NIGHT. WHAT THIS MEANS IS
HIGH TEMPERATURES MONDAY AND TUESDAY WILL BE IN THE 80S WITH LOW
90S OUT WEST WHERE MID LEVEL DRY AIR DUE TO THOSE AFOREMENTIONED
SOUTHWESTERLIES WILL BE MIXED DOWN.
AN UPPER TROF WILL MOVE OVER THE WESTERN CONUS AND FOUR CORNERS
THROUGH TUESDAY. PRESSURE FALLS AHEAD OF THIS FEATURE WILL INDUCE
LEE TROUGHING ACROSS THE ROCKIES SOUTHWARD INTO THE SIERRA MADRES.
THIS WILL HELP RATCHET UP THE SOUTHERLY SURFACE WINDS MONDAY AND
TUESDAY AS WELL. SURFACE LOW PRESSURE WILL HEAD OUT OF THE HIGH
PLAINS TUESDAY AND DRAG A COLD FRONT INTO CENTRAL AND SOUTHERN
TEXAS WEDNESDAY. WIDESPREAD STRATUS ON A 40KT LOW LEVEL JET WILL
KEEP THE AREA MOSTLY CLOUDY THROUGH THE DAY WHICH WILL HOLD HIGH
TEMPERATURES DOWN INTO THE LOW 80S. TIMING DIFFERENCES EXIST
BETWEEN THE GFS/ECMWF CONCERNING THE PASSAGE OF THE FRONT WITH GFS
A LITTLE FASTER BRINGING THE FRONT THROUGH WEDNESDAY AND THE ECMWF
AT WEDNESDAY NIGHT AND THURSDAY. DESPITE THE TIMING DIFFERENCES
EXPECT STRONG NORTHERLY WINDS AND COOLER TEMPERATURES TO ROUND OUT
THE WORK WEEK. AS FAR AS POPS GO ASSOCIATED WITH THE FRONT LOOKS
LIKE CAPPING WILL BE STRONG AND LIMIT MOST PRECIPITATION TO WELL
OFFSHORE. BOTH ECMWF AND GFS HINT AT WEAK COASTAL TROUGHING FRIDAY
WITH A SLIGHT CHANCE FOR LIGHT RAIN ALONG AND EAST OF HWY 77.
MARINE /NOW THROUGH THROUGH SATURDAY/...STRONG HIGH PRESSURE
OVER THE PLAINS WILL EXTEND SOUTH OVER THE NORTH GULF AND WILL SET
UP MDT TO FRESH EAST NORTHEAST WINDS...BUT PERHAPS OF MORE
SIGNIFICANCE WILL BE THE LONG FETCH ACROSS THE NORTH GULF...WHICH
WILL SUPPORT ELEVATED SEAS DUE TO A SWELL COMPONENT. THE ONGOING
SMALL CRAFT ADVISORY FOR THE GULF WILL THUS PERSIST THROUGH THE
SHORT TERM. WAVE HEIGHTS OF 7 TO 9 FEET WILL PERSIST ON THE OPEN
GULF THROUGH SATURDAY AND INTO THE LONG TERM.
SATURDAY NIGHT THROUGH TUESDAY...MODERATE TO STRONG EAST WINDS
SATURDAY NIGHT WILL WEAKEN AND TURN MORE SOUTHEASTERLY SUNDAY AS A
WARM FRONT MOVES NORTHWARD THROUGH THE COASTAL WATERS. SMALL CRAFT
ADVISORIES WILL BE ONGOING INTO THE LONG TERM AND WILL BE NEED
THROUGH SUNDAY AS SEA HEIGHTS WILL REMAIN AROUND 7 FEET THROUGH
SUNDAY AFTERNOON. WINDS AND SEAS BECOME MORE MODERATE MONDAY WITH
CONDITIONS DETERIORATING MONDAY NIGHT AND TUESDAY AS LOW PRESSURE
DEEPENS TO OUR WEST AND SOUTHEASTERLY WINDS STRENGTHEN. SMALL
CRAFT ADVISORIES WILL BE LIKELY MONDAY NIGHT INTO TUESDAY.
&&
.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 3 AM CST SATURDAY FOR GMZ150-155-170-
175.
&&
$$
THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV
67/52
AREA FORECAST DISCUSSION
NWS BROWNSVILLE TX
1035 AM CST FRI FEB 27 2015
.DISCUSSION...THE COLD AIR CONTINUES TO MOVE SOUTH ACROSS
THE CWA ESPECIALLY TOWARDS THE WESTERN PORTION OF THE CWA.
THIS HAS SHIFTED WINDS MORE NORTHWEST KEEPING TEMPERATURES
COOLER THAN EXPECTED. KEPT A NORTH TO NORTHWEST FLOW ACROSS
THE AREA WITH A SHARP TEMPERATURE GRADIENT FROM WEST TO EAST.
LOWER HIGH TEMPERATURES A FEW DEGREES MORE TOWARDS THE WEST
AND WITH A EASTERLY FLOW DEVELOPING KEPT WARMER TEMPERATURES
IN THE MID 60S. CHANCE OF RAIN REMAINS THE SAME AND THERE ARE
NO OTHER CHANGES DONE TO THE FORECAST AT THIS TIME.
&&
.PREV DISCUSSION... /ISSUED 547 AM CST FRI FEB 27 2015/
DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.
AVIATION...HIGH CLOUDS ARE EXPECTED TO DECREASE AS THE UPPER JET
SHIFTS DOWNSTREAM. COLD AIR BEHIND A COLD FRONT IS FILTERING INTO
THE CWA THIS MORNING...AND THE ISENTROPIC LIFT WILL SUPPORT
LOWERING CEILINGS...WITH LIGHT RAIN AND DRIZZLE POSSIBLE LATER IN
THE DAY. LIGHT TO MODERATE NORTHEAST WINDS WILL BECOME VERY LIGHT
THIS EVE...BUT WILL THEN PICK UP AGAIN SLIGHTLY AFTER MIDNIGHT.
CEILINGS SHOULD LOWER TO MVFR BY MID MORNING AND THEN TO IFR LATER
TODAY. THE GUIDANCE VARIES A LITTLE FOR THIS EVENING...WITH THE
GFS KEEPING CEILINGS A CATEGORY HIGHER THAN THE NAM...BUT MVFR IS
THE MIDDLE GROUND FOR NOW.
&&
PREV DISCUSSION... /ISSUED 254 AM CST FRI FEB 27 2015/
SHORT TERM /NOW THROUGH SATURDAY/...A COLD FRONT IS WORKING ITS
WAY THROUGH THE CWA THIS MORNING...WITHOUT TOO MUCH FANFARE.
SOUTHERN EDGE AND RR QUAD OF AN UPPER JET STREAK RESULTED IN A
RIBBON OF UPPER CLOUDS STILL OVER THE SOUTHEASTERN CORNER OF THE
CWA BUT THAT SHOULD FADE TODAY AS THICKER LOW CLOUDS TAKE OVER.
LOW CLOUDS ARE THICKENING FROM WEST TO EAST. NORTHEAST WINDS THAT
WERE ALREADY IN PLACE ARE RECEIVING SOME REINFORCEMENT AND DEW
POINTS ARE DECREASING BEHIND THE FRONT. LOOKING FOR A
COOL...CLOUDY DAY ACROSS DEEP SOUTH TEXAS AND THE RGV TODAY WITH A
RANGE OF HIGH TEMPS FROM THE UPPER 40S FAR WEST AND NORTH TO THE
LOWER 60S FOR CAMERON AND WILLACY COUNTIES. LIGHT RAIN AND DRIZZLE
CHANCES WILL INCREASE LATER TODAY AND TONIGHT AS THE COOLER AIR
BECOMES ESTABLISHED. LOW TEMPS TONIGHT WILL BE MAINLY IN THE 40S
AND 50S WITH LIGHT WINDS AS HIGH PRESSURE SPREADS OVER THE AREA.
LOOKS LIKE THE HIGH PRESSURE WILL THEN SHIFT EAST IN SHORT ORDER.
WINDS WILL VEER TO EAST BY SATURDAY AND THE RETURN FLOW WILL
SUPPORT HIGH TEMPS IN THE 60S...THOUGH AMPLE CLOUD COVER WILL
CONTINUE AND A MID LEVEL FLOW THAT WILL BACK FROM WEST TO
SOUTHWEST WILL HELP ENSURE THAT OVERRUNNING PERSISTS.
LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...OVERRUNNING LIGHT
RAIN CHANCES ACROSS DEEP SOUTH TEXAS AND THE RGV WILL COME TO AN
END SUNDAY AS COASTAL TROUGHING WEAKENS AND A WARM FRONT LIFTS
NORTHWARD. WINDS BECOME SOUTHEASTERLY BY SUNDAY MORNING AND
MOISTURE DECREASES. COLD AIR IS SHUNTED NORTH AND EAST FOR THE
START OF THE WORK WEEK WITH 850MB TEMPERATURES RISING FROM 13C
SUNDAY MORNING TO 22C BY TUESDAY NIGHT. 700MB SOUTHWESTERLIES
SPREAD OVER THE AREA BEGINNING MONDAY NIGHT. WHAT THIS MEANS IS
HIGH TEMPERATURES MONDAY AND TUESDAY WILL BE IN THE 80S WITH LOW
90S OUT WEST WHERE MID LEVEL DRY AIR DUE TO THOSE AFOREMENTIONED
SOUTHWESTERLIES WILL BE MIXED DOWN.
AN UPPER TROF WILL MOVE OVER THE WESTERN CONUS AND FOUR CORNERS
THROUGH TUESDAY. PRESSURE FALLS AHEAD OF THIS FEATURE WILL INDUCE
LEE TROUGHING ACROSS THE ROCKIES SOUTHWARD INTO THE SIERRA MADRES.
THIS WILL HELP RATCHET UP THE SOUTHERLY SURFACE WINDS MONDAY AND
TUESDAY AS WELL. SURFACE LOW PRESSURE WILL HEAD OUT OF THE HIGH
PLAINS TUESDAY AND DRAG A COLD FRONT INTO CENTRAL AND SOUTHERN
TEXAS WEDNESDAY. WIDESPREAD STRATUS ON A 40KT LOW LEVEL JET WILL
KEEP THE AREA MOSTLY CLOUDY THROUGH THE DAY WHICH WILL HOLD HIGH
TEMPERATURES DOWN INTO THE LOW 80S. TIMING DIFFERENCES EXIST
BETWEEN THE GFS/ECMWF CONCERNING THE PASSAGE OF THE FRONT WITH GFS
A LITTLE FASTER BRINGING THE FRONT THROUGH WEDNESDAY AND THE ECMWF
AT WEDNESDAY NIGHT AND THURSDAY. DESPITE THE TIMING DIFFERENCES
EXPECT STRONG NORTHERLY WINDS AND COOLER TEMPERATURES TO ROUND OUT
THE WORK WEEK. AS FAR AS POPS GO ASSOCIATED WITH THE FRONT LOOKS
LIKE CAPPING WILL BE STRONG AND LIMIT MOST PRECIPITATION TO WELL
OFFSHORE. BOTH ECMWF AND GFS HINT AT WEAK COASTAL TROUGHING FRIDAY
WITH A SLIGHT CHANCE FOR LIGHT RAIN ALONG AND EAST OF HWY 77.
MARINE /NOW THROUGH THROUGH SATURDAY/...STRONG HIGH PRESSURE
OVER THE PLAINS WILL EXTEND SOUTH OVER THE NORTH GULF AND WILL SET
UP MDT TO FRESH EAST NORTHEAST WINDS...BUT PERHAPS OF MORE
SIGNIFICANCE WILL BE THE LONG FETCH ACROSS THE NORTH GULF...WHICH
WILL SUPPORT ELEVATED SEAS DUE TO A SWELL COMPONENT. THE ONGOING
SMALL CRAFT ADVISORY FOR THE GULF WILL THUS PERSIST THROUGH THE
SHORT TERM. WAVE HEIGHTS OF 7 TO 9 FEET WILL PERSIST ON THE OPEN
GULF THROUGH SATURDAY AND INTO THE LONG TERM.
SATURDAY NIGHT THROUGH TUESDAY...MODERATE TO STRONG EAST WINDS
SATURDAY NIGHT WILL WEAKEN AND TURN MORE SOUTHEASTERLY SUNDAY AS A
WARM FRONT MOVES NORTHWARD THROUGH THE COASTAL WATERS. SMALL CRAFT
ADVISORIES WILL BE ONGOING INTO THE LONG TERM AND WILL BE NEED
THROUGH SUNDAY AS SEA HEIGHTS WILL REMAIN AROUND 7 FEET THROUGH
SUNDAY AFTERNOON. WINDS AND SEAS BECOME MORE MODERATE MONDAY WITH
CONDITIONS DETERIORATING MONDAY NIGHT AND TUESDAY AS LOW PRESSURE
DEEPENS TO OUR WEST AND SOUTHEASTERLY WINDS STRENGTHEN. SMALL
CRAFT ADVISORIES WILL BE LIKELY MONDAY NIGHT INTO TUESDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL 63 55 69 64 / 50 40 40 30
BROWNSVILLE 64 53 70 64 / 50 40 30 30
HARLINGEN 56 53 70 63 / 50 40 40 30
MCALLEN 53 48 70 62 / 30 30 20 20
RIO GRANDE CITY 48 46 68 60 / 30 50 30 20
SOUTH PADRE ISLAND 64 56 69 65 / 50 40 40 30
&&
.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 3 AM CST SATURDAY FOR GMZ150-155-170-
175.
&&
$$
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