Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 02/20/15
AREA FORECAST DISCUSSION
NWS ALBANY NY
301 PM EST WED FEB 18 2015
.SYNOPSIS...
CLOUDS WILL INCREASE THROUGH THE DAY AHEAD OF AN
APPROACHING ARCTIC COLD FRONT. THIS FRONT WILL BRING SOME SNOW
SHOWERS AND SNOW SQUALLS TO THE REGION THIS EVENING INTO TONIGHT.
BITTER COLD TEMPERATURES...ALONG WITH A FEW ADDITIONAL SNOW
SHOWERS...WILL BE IN PLACE ACROSS THE REGION FOR THURSDAY INTO
FRIDAY. ANOTHER STORM SYSTEM WILL IMPACT THE AREA OVER THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 915 AM EST...A STRONG SHORTWAVE AND ASSOCIATED SFC COLD
FRONT IS SITUATED UPSTREAM OF THE REGION OVER THE GREAT LAKES.
SOME MID AND HIGH LEVEL CLOUDS HAVE STARTED TO MOVE INTO OUR
AREA...BUT THE MAJORITY OF THESE CLOUDS HAVE BEEN RATHER THIN.
WITH A DEEP SNOWPACK AND LIGHT WINDS IN PLACE...TEMPS HAVE BEEN
VERY COLD SO FAR THIS MORNING...WITH MOST AREAS ONLY IN THE SINGLE
DIGITS TO SLIGHTLY BELOW ZERO.
CLOUDS WILL CONTINUE TO LOWER AND THICKEN THROUGHOUT THE DAY AS
THE ARCTIC FRONT CONTINUES TO MOVE EASTWARD TOWARDS THE AREA. MOST
AREAS LOOK TO BE MOSTLY CLOUDY BY AFTERNOON. IT SHOULD STAY DRY
ACROSS THE REGION THROUGH THE EARLY EVENING...AS THE LATEST 09Z
3KM HRRR SHOWS A BAND OF HEAVY SNOW SHOWERS STILL BACK OVER CNY
BETWEEN THE FINGER LAKES AND THE SYRACUSE AREA BY ABOUT 5-6 PM.
WILL START TO RAISE POPS FOR WESTERN AREAS FOR THE LATE AFTN/EARLY
EVENING IN CASE THIS SPEEDS UP...BUT MOST AREAS WON/T SEE ANY SNOW
UNTIL TONIGHT.
HIGH TEMPS TODAY WILL BE A LITTLE WARMER THAN TUESDAY...BUT STILL
BELOW NORMAL...WITH TEMPS RANGING FROM THE MID TEENS IN THE
ADIRONDACKS TO THE MID 20S IN THE HUDSON VALLEY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
AS OF 1235 PM EST...WE ACTUALLY NEEDED TO RAISE TEMPERATURES SEVERAL
DEGREES AS MOST AREAS WERE ALREADY APPROACHING THE PREVIOUSLY
ADVERTISED HIGHS. THIS MEAN HIGHS SHOULD REACH THE UPPER 20S TO NEAR
30 WELL SOUTH OF THE CAPITAL REGION...MID 20S LOCALLY IN THE CAPITAL
REGION...CLOSER TO 20 FURTHER NORTH. WITH LITTLE OR NO WIND...THIS
WILL MAKE THE COLD EASEIR TO TAKE TODAY.
ALSO...SLOWED DOWN THE ARRIVAL OF CLOUDS AND SNOW SHOWERS JUST A
LITTLE HAS THE DRY AIR HOLDS TIGHT.
THE ARCTIC COLD FRONT WILL BE PASSING FROM WEST TO EAST ACROSS THE
REGION TONIGHT. THE FRONT WILL BE SLOWED IN ITS PROGRESS...AS A
WEAK WAVE OF LOW PRESSURE DEVELOPS ALONG THE COLD/OCCLUDED
BOUNDARY. THE 00Z WFO BTV 4KM WRF SHOWS AN AREA OF SNOW SHOWERS
AND EMBEDDED SQUALLS IMPACTING THE REGION FROM WEST TO EAST DURING
THE OVERNIGHT HOURS. THE 00Z/06Z NAM ALSO SUGGESTS THIS WILL
OCCUR...ALTHOUGH THERE ARE SOME SLIGHT DIFFERENCES IN THE TIMING
DUE TO THE SLOW NATURE OF THE FRONTAL BOUNDARY. HAVE RAISED POPS
TO LIKELY FOR A FEW HOURS IN MOST LOCATIONS...WITH A LIGHT
ACCUMULATION OF 1-3 INCHES EXPECTED TONIGHT INTO THURSDAY
MORNING...WITH THE HIGHEST AMOUNTS FOR THE HIGHER ELEVATIONS. ALTHOUGH
QPF AMOUNTS ARE LIGHT...RATIOS ARE EXPECTED TO BE RATHER HIGH...AS
THE NAM BUFKIT SOUNDING SHOWS GOOD LIFT /OMEGA/ THROUGH THE
OPTIMAL DENDRITIC SNOW GROWTH LAYER. TEMPS LOOK TO COOL OFF
QUICKLY BEHIND THE BOUNDARY...WITH MINS LOWEST FOR WESTERN AREAS
/ZERO TO 5/ AND HIGHEST FOR EASTERN/SOUTHERN AREAS /GENERALLY 10
TO 15/.
WIDESPREAD SNOW SHOWERS WILL BE ONGOING THURSDAY MORNING...BUT
WILL BE TAPERING OFF BY MIDDAY FOR MOST AREAS...AS THE FRONT
CONTINUES TO PUSH EASTWARD...AND THE WAVE ON THE BOUNDARY RE-
DEVELOPS AND RAPIDLY STRENGTHENS OFF THE EASTERN NEW ENGLAND
COAST. TEMPS WON/T RISE TOO MUCH ON THURSDAY WITH THE STRONG COLD
AIR ADVECTION IN PLACE...AS 850 HPA TEMPS FALL TO -20 TO -25
DEGREES C. HIGHS WILL ONLY REACH THE SINGLE DIGITS TO MID TEENS.
SOME ADDITIONAL UPSLOPE SNOW MAY OCCUR WITH IN THE NW FLOW FOR
THE HIGH TERRAIN AREAS OF WESTERN NEW ENGLAND...AND SOME LAKE
ENHANCED SNOW SHOWERS COULD ALSO BE OCCURRING INTO THE MOHAWK
VALLEY/SCHOHARIE COUNTY THANKS TO THE FLOW MOVING ACROSS LAKE
ONTARIO. SOME ADDITIONAL ACCUMULATION OF AN INCH OR TWO IS
POSSIBLE FOR THESE AREAS.
WINDS WILL BE STARTING TO PICK UP BY THURSDAY AFTERNOON THANKS TO
THE INCREASING PRESSURE GRADIENT...AND WILL BE GUSTING 20-30 MPH
AT TIMES. THIS LOOK TO CONTINUE INTO THURSDAY NIGHT AS WELL...AND
TEMPS WILL BE FALLING TO ZERO TO -15 DEGREES F FOR LOW TEMPS FOR
THURSDAY NIGHT. WITH THE STRONG WINDS AND COLD TEMPS...WIND
CHILLS WILL CERTAINLY BE AN ISSUE. ADVISORY LEVEL WIND CHILLS
APPEAR LIKELY FOR MOST AREAS...AND A FEW SPOTS IN THE
ADIRONDACKS/CATSKILLS COULD POTENTIALLY REACH WARNING LEVELS AS
WELL. WILL CONTINUE TO HIGHLIGHT THESE THREATS IN THE HWO
STATEMENT. OUTSIDE OF THE BRUTALLY COLD TEMPS...SOME LINGERING
HIGH TERRAIN SNOW SHOWERS/FLURRIES ARE POSSIBLE...ALTHOUGH NOT
MUCH ADDITIONAL ACCUMULATION IS EXPECTED.
BITTER COLD TEMPS AND LOW WIND CHILL WILL REMAIN IN PLACE FOR
FRIDAY...ALTHOUGH WINDS WILL START TO REDUCE BY LATER IN THE DAY.
OUTSIDE A FEW FLURRIES/SNOW SHOWERS FOR THE WESTERN
ADIRONDACKS...NO PRECIP IS EXPECTED. MAX TEMPS WILL ONLY REACH THE
SINGLE DIGITS TO LOW TEENS...WITH A FEW SPOTS IN THE HIGH TERRAIN
REMAINING BELOW ZERO.
ANOTHER BITTER COLD NIGHT IS EXPECTED FOR FRIDAY NIGHT...BUT WIND
CHILLS WON/T BE AN ADDITIONAL CONCERN THANKS TO A LIGHT TO CALM
WINDS. STILL...TEMPS WILL BE VERY COLD...WITH MOST AREAS BELOW
ZERO ONCE AGAIN...AND SOME HIGH TERRAIN LOCATIONS -10 TO -20
DEGREES F. IT SHOULD REMAIN DRY...WITH A PARTLY TO MOSTLY CLEAR
SKY...AS HIGH PRESSURE SLIDES BY TO THE SOUTH OF THE AREA.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
APPROACHING UPPER ENERGY WILL RESULT IN THICKENING CLOUDS AND SLOWLY
INCREASING COVERAGE OF LIGHT SNOW. WARM ADVECTION WILL INCREASE...
AS WILL ISENTROPIC LIFT. SO HIGHS SATURDAY IN THE UPPER TEENS TO MID
20S...WITH JUST CHANCES FOR LIGHT SNOW IN THE AFTERNOON.
COVERAGE OF PRECIPITATION WILL INCREASE SATURDAY NIGHT INTO
SUNDAY...AS WILL WARM ADVECTION AND ISENTROPIC LIFT. LOW LEVEL JET
ENERGY WILL SPREAD NORTH AND EAST...ENHANCING THE WARM ADVECTION...
ESPECIALLY SUNDAY. THERE ARE SOME CONFLICTS COMPARING DETERMINISTIC
GUIDANCE AND ENSEMBLE GUIDANCE. DETERMINISTIC GUIDANCE SUGGESTS A
PRECIPITATION TRANSITION TO MIXED PRECIPITATION OR COLD RAIN FOR THE
MUCH OF THE FORECAST AREA SUNDAY...WHILE ENSEMBLE MEAN THERMAL
PROFILES SUGGEST THE DETERMINISTIC GUIDANCE IS ON THE WARMER SIDE OF
THE ENSEMBLE RANGE.
THE MEAN EASTERN NORTH AMERICAN UPPER TROUGH WILL HAVE TO RETROGRADE
QUITE A BIT FOR ENOUGH WARM AIR TO FLOOD THE EASTERN U.S. TO BRING
RAIN DURING AN OTHERWISE SNOWY AND COLD WINTER. THERE IS STILL LOTS
OF TIME TO WATCH THE DEVELOPMENT OF THIS SYSTEM...AND UNTIL THERE
ARE CLEAR SIGNALS FOR MIXED PRECIPITATION OR COLD RAIN...WILL
INDICATE SNOW IN MOST AREAS THROUGH SUNDAY...WITH THE EXCEPTION OF
PARTS OF THE EASTERN CATSKILLS...MID HUDSON VALLEY AND NW CT...WHERE
RAIN AND SNOW WILL BE INDICATED. HIGHS SUNDAY AROUND 30 TO THE MID
30S...MID TO UPPER 20S NORTHERN AREAS.
ONCE THE SYSTEM EXITS SUNDAY NIGHT...ANOTHER PUSH OF VERY COLD AIR
SPILLS INTO THE REGION...WITH MUCH BELOW NORMAL TEMPERATURES. HIGHS
MONDAY IN THE TEENS TO LOWER 20S...SOME UPPER SINGLE NUMBERS IN THE
SOUTHERN ADIRONDACKS. HIGHS TUESDAY IN THE MID TEENS TO LOWER 20S.
&&
.AVIATION /20Z WEDNESDAY THROUGH MONDAY/...
CIRRUS CLOUDS HAVE ALREADY STREAMED ACRS THE TAF SITES ALONG WITH
SOME MID LEVEL CLOUDS AHEAD OF AN APPROACHING COLD FRONT. OVERALL
CLOUDS WILL THICKEN AND LOWER THIS AFTERNOON AND EVENING AS THE
COLD FRONT MOVES INTO THE REGION BRINGING CHANCE OF SNOW SHOWERS
TO THE AREA...MAINLY AFTER 00Z/THU. KEEPING VFR CONDITIONS WITH
VCSH UNTIL AROUND 06Z...WHEN MANY AREAS SHOULD SEE SOME
INTERMITTENT SNOW OR SNOW SHOWERS. MVFR CEILINGS AND VISIBILITIES
SHOULD ACCOMPANY THE SNOW LOWERING TO IFR CONDITIONS THURSDAY
MORNING. WINDS CALM TO LIGHT AND VARIABLE THROUGH 06Z AND THEN
BCMG NORTHWEST 10-14KTS THURSDAY MORNING.
OUTLOOK...
WED NIGHT-THU: MODERATE OPERATIONAL IMPACT. CHC -SHSN.
THU NIGHT-FRI NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
SAT-SUN: MODERATE OPERATIONAL IMPACT. CHC SN.
&&
.HYDROLOGY...
ICE WILL CONTINUE TO THICKEN ON AREA RIVERS...STREAMS...LAKES...AND
PONDS...AS CONTINUED BELOW NORMAL TEMPERATURES REMAIN IN PLACE
THROUGH THE REMAINDER OF THE WEEK. TEMPERATURES LOOK TO STAY BELOW
FREEZING THROUGH SATURDAY.
ANY PRECIP...ALL IN THE FORM OF SNOW...WILL BE FAIRLY LIGHT OVER
THE NEXT FEW DAYS. SOME SNOW SHOWERS ARE POSSIBLE BETWEEN TODAY
AND TOMORROW...BUT THIS WILL HAVE LITTLE TO NO IMMEDIATE IMPACT ON
AREA WATERWAYS. SOME GAGES WILL EXPERIENCE ICE EFFECTS...AND SOME
ERRONEOUS DATA MAY BE SEEN FROM TIME TO TIME.
A STORM SYSTEM WILL IMPACT THE REGION OVER THE WEEKEND WITH SOME
ADDITIONAL PRECIPITATION...MAINLY ON SUNDAY. IT IS STILL UNCLEAR
IN WHAT FORM THIS PRECIP WILL BE /RAIN...SNOW...OR MIXED
PRECIPITATION/ AND EXACT AMOUNTS ARE STILL FAR FROM CERTAIN. WE
WILL NEED TO MONITOR THE POTENTIAL FOR HOW THIS STORM MAY IMPACT
THE HYDROLOGIC AREA.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING
OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE
VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON
OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...FRUGIS/HWJIV
NEAR TERM...FRUGIS/HWJIV
SHORT TERM...HWJIV
LONG TERM...IRL
AVIATION...HWJIV/NAS
HYDROLOGY...FRUGIS/HWJIV
AREA FORECAST DISCUSSION
NWS ALBANY NY
1235 PM EST WED FEB 18 2015
.SYNOPSIS...
CLOUDS WILL INCREASE THROUGH THE DAY AHEAD OF AN
APPROACHING ARCTIC COLD FRONT. THIS FRONT WILL BRING SOME SNOW
SHOWERS AND SNOW SQUALLS TO THE REGION THIS EVENING INTO TONIGHT.
BITTER COLD TEMPERATURES...ALONG WITH A FEW ADDITIONAL SNOW
SHOWERS...WILL BE IN PLACE ACROSS THE REGION FOR THURSDAY INTO
FRIDAY. ANOTHER STORM SYSTEM WILL IMPACT THE AREA OVER THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 915 AM EST...A STRONG SHORTWAVE AND ASSOCIATED SFC COLD
FRONT IS SITUATED UPSTREAM OF THE REGION OVER THE GREAT LAKES.
SOME MID AND HIGH LEVEL CLOUDS HAVE STARTED TO MOVE INTO OUR
AREA...BUT THE MAJORITY OF THESE CLOUDS HAVE BEEN RATHER THIN.
WITH A DEEP SNOWPACK AND LIGHT WINDS IN PLACE...TEMPS HAVE BEEN
VERY COLD SO FAR THIS MORNING...WITH MOST AREAS ONLY IN THE SINGLE
DIGITS TO SLIGHTLY BELOW ZERO.
CLOUDS WILL CONTINUE TO LOWER AND THICKEN THROUGHOUT THE DAY AS
THE ARCTIC FRONT CONTINUES TO MOVE EASTWARD TOWARDS THE AREA. MOST
AREAS LOOK TO BE MOSTLY CLOUDY BY AFTERNOON. IT SHOULD STAY DRY
ACROSS THE REGION THROUGH THE EARLY EVENING...AS THE LATEST 09Z
3KM HRRR SHOWS A BAND OF HEAVY SNOW SHOWERS STILL BACK OVER CNY
BETWEEN THE FINGER LAKES AND THE SYRACUSE AREA BY ABOUT 5-6 PM.
WILL START TO RAISE POPS FOR WESTERN AREAS FOR THE LATE AFTN/EARLY
EVENING IN CASE THIS SPEEDS UP...BUT MOST AREAS WON/T SEE ANY SNOW
UNTIL TONIGHT.
HIGH TEMPS TODAY WILL BE A LITTLE WARMER THAN TUESDAY...BUT STILL
BELOW NORMAL...WITH TEMPS RANGING FROM THE MID TEENS IN THE
ADIRONDACKS TO THE MID 20S IN THE HUDSON VALLEY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
AS OF 1235 PM EST...WE ACTUALLY NEEDED TO RAISE TEMPERATURES SEVERAL
DEGREES AS MOST AREAS WERE ALREADY APPROACHING THE PREVIOUSLY
ADVERTISED HIGHS. THIS MEAN HIGHS SHOULD REACH THE UPPER 20S TO NEAR
30 WELL SOUTH OF THE CAPITAL REGION...MID 20S LOCALLY IN THE CAPITAL
REGION...CLOSER TO 20 FURTHER NORTH. WITH LITTLE OR NO WIND...THIS
WILL MAKE THE COLD EASEIR TO TAKE TODAY.
ALSO...SLOWED DOWN THE ARRIVAL OF CLOUDS AND SNOW SHOWERS JUST A
LITTLE HAS THE DRY AIR HOLDS TIGHT.
THE ARCTIC COLD FRONT WILL BE PASSING FROM WEST TO EAST ACROSS THE
REGION TONIGHT. THE FRONT WILL BE SLOWED IN ITS PROGRESS...AS A
WEAK WAVE OF LOW PRESSURE DEVELOPS ALONG THE COLD/OCCLUDED
BOUNDARY. THE 00Z WFO BTV 4KM WRF SHOWS AN AREA OF SNOW SHOWERS
AND EMBEDDED SQUALLS IMPACTING THE REGION FROM WEST TO EAST DURING
THE OVERNIGHT HOURS. THE 00Z/06Z NAM ALSO SUGGESTS THIS WILL
OCCUR...ALTHOUGH THERE ARE SOME SLIGHT DIFFERENCES IN THE TIMING
DUE TO THE SLOW NATURE OF THE FRONTAL BOUNDARY. HAVE RAISED POPS
TO LIKELY FOR A FEW HOURS IN MOST LOCATIONS...WITH A LIGHT
ACCUMULATION OF 1-3 INCHES EXPECTED TONIGHT INTO THURSDAY
MORNING...WITH THE HIGHEST AMOUNTS FOR THE HIGHER ELEVATIONS. ALTHOUGH
QPF AMOUNTS ARE LIGHT...RATIOS ARE EXPECTED TO BE RATHER HIGH...AS
THE NAM BUFKIT SOUNDING SHOWS GOOD LIFT /OMEGA/ THROUGH THE
OPTIMAL DENDRITIC SNOW GROWTH LAYER. TEMPS LOOK TO COOL OFF
QUICKLY BEHIND THE BOUNDARY...WITH MINS LOWEST FOR WESTERN AREAS
/ZERO TO 5/ AND HIGHEST FOR EASTERN/SOUTHERN AREAS /GENERALLY 10
TO 15/.
WIDESPREAD SNOW SHOWERS WILL BE ONGOING THURSDAY MORNING...BUT
WILL BE TAPERING OFF BY MIDDAY FOR MOST AREAS...AS THE FRONT
CONTINUES TO PUSH EASTWARD...AND THE WAVE ON THE BOUNDARY RE-
DEVELOPS AND RAPIDLY STRENGTHENS OFF THE EASTERN NEW ENGLAND
COAST. TEMPS WON/T RISE TOO MUCH ON THURSDAY WITH THE STRONG COLD
AIR ADVECTION IN PLACE...AS 850 HPA TEMPS FALL TO -20 TO -25
DEGREES C. HIGHS WILL ONLY REACH THE SINGLE DIGITS TO MID TEENS.
SOME ADDITIONAL UPSLOPE SNOW MAY OCCUR WITH IN THE NW FLOW FOR
THE HIGH TERRAIN AREAS OF WESTERN NEW ENGLAND...AND SOME LAKE
ENHANCED SNOW SHOWERS COULD ALSO BE OCCURRING INTO THE MOHAWK
VALLEY/SCHOHARIE COUNTY THANKS TO THE FLOW MOVING ACROSS LAKE
ONTARIO. SOME ADDITIONAL ACCUMULATION OF AN INCH OR TWO IS
POSSIBLE FOR THESE AREAS.
WINDS WILL BE STARTING TO PICK UP BY THURSDAY AFTERNOON THANKS TO
THE INCREASING PRESSURE GRADIENT...AND WILL BE GUSTING 20-30 MPH
AT TIMES. THIS LOOK TO CONTINUE INTO THURSDAY NIGHT AS WELL...AND
TEMPS WILL BE FALLING TO ZERO TO -15 DEGREES F FOR LOW TEMPS FOR
THURSDAY NIGHT. WITH THE STRONG WINDS AND COLD TEMPS...WIND
CHILLS WILL CERTAINLY BE AN ISSUE. ADVISORY LEVEL WIND CHILLS
APPEAR LIKELY FOR MOST AREAS...AND A FEW SPOTS IN THE
ADIRONDACKS/CATSKILLS COULD POTENTIALLY REACH WARNING LEVELS AS
WELL. WILL CONTINUE TO HIGHLIGHT THESE THREATS IN THE HWO
STATEMENT. OUTSIDE OF THE BRUTALLY COLD TEMPS...SOME LINGERING
HIGH TERRAIN SNOW SHOWERS/FLURRIES ARE POSSIBLE...ALTHOUGH NOT
MUCH ADDITIONAL ACCUMULATION IS EXPECTED.
BITTER COLD TEMPS AND LOW WIND CHILL WILL REMAIN IN PLACE FOR
FRIDAY...ALTHOUGH WINDS WILL START TO REDUCE BY LATER IN THE DAY.
OUTSIDE A FEW FLURRIES/SNOW SHOWERS FOR THE WESTERN
ADIRONDACKS...NO PRECIP IS EXPECTED. MAX TEMPS WILL ONLY REACH THE
SINGLE DIGITS TO LOW TEENS...WITH A FEW SPOTS IN THE HIGH TERRAIN
REMAINING BELOW ZERO.
ANOTHER BITTER COLD NIGHT IS EXPECTED FOR FRIDAY NIGHT...BUT WIND
CHILLS WON/T BE AN ADDITIONAL CONCERN THANKS TO A LIGHT TO CALM
WINDS. STILL...TEMPS WILL BE VERY COLD...WITH MOST AREAS BELOW
ZERO ONCE AGAIN...AND SOME HIGH TERRAIN LOCATIONS -10 TO -20
DEGREES F. IT SHOULD REMAIN DRY...WITH A PARTLY TO MOSTLY CLEAR
SKY...AS HIGH PRESSURE SLIDES BY TO THE SOUTH OF THE AREA.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
APPROACHING UPPER ENERGY WILL RESULT IN THICKENING CLOUDS AND SLOWLY
INCREASING COVERAGE OF LIGHT SNOW. WARM ADVECTION WILL INCREASE...
AS WILL ISENTROPIC LIFT. SO HIGHS SATURDAY IN THE UPPER TEENS TO MID
20S...WITH JUST CHANCES FOR LIGHT SNOW IN THE AFTERNOON.
COVERAGE OF PRECIPITATION WILL INCREASE SATURDAY NIGHT INTO
SUNDAY...AS WILL WARM ADVECTION AND ISENTROPIC LIFT. LOW LEVEL JET
ENERGY WILL SPREAD NORTH AND EAST...ENHANCING THE WARM ADVECTION...
ESPECIALLY SUNDAY. THERE ARE SOME CONFLICTS COMPARING DETERMINISTIC
GUIDANCE AND ENSEMBLE GUIDANCE. DETERMINISTIC GUIDANCE SUGGESTS A
PRECIPITATION TRANSITION TO MIXED PRECIPITATION OR COLD RAIN FOR THE
MUCH OF THE FORECAST AREA SUNDAY...WHILE ENSEMBLE MEAN THERMAL
PROFILES SUGGEST THE DETERMINISTIC GUIDANCE IS ON THE WARMER SIDE OF
THE ENSEMBLE RANGE.
THE MEAN EASTERN NORTH AMERICAN UPPER TROUGH WILL HAVE TO RETROGRADE
QUITE A BIT FOR ENOUGH WARM AIR TO FLOOD THE EASTERN U.S. TO BRING
RAIN DURING AN OTHERWISE SNOWY AND COLD WINTER. THERE IS STILL LOTS
OF TIME TO WATCH THE DEVELOPMENT OF THIS SYSTEM...AND UNTIL THERE
ARE CLEAR SIGNALS FOR MIXED PRECIPITATION OR COLD RAIN...WILL
INDICATE SNOW IN MOST AREAS THROUGH SUNDAY...WITH THE EXCEPTION OF
PARTS OF THE EASTERN CATSKILLS...MID HUDSON VALLEY AND NW CT...WHERE
RAIN AND SNOW WILL BE INDICATED. HIGHS SUNDAY AROUND 30 TO THE MID
30S...MID TO UPPER 20S NORTHERN AREAS.
ONCE THE SYSTEM EXITS SUNDAY NIGHT...ANOTHER PUSH OF VERY COLD AIR
SPILLS INTO THE REGION...WITH MUCH BELOW NORMAL TEMPERATURES. HIGHS
MONDAY IN THE TEENS TO LOWER 20S...SOME UPPER SINGLE NUMBERS IN THE
SOUTHERN ADIRONDACKS. HIGHS TUESDAY IN THE MID TEENS TO LOWER 20S.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
CIRRUS CLOUDS HAVE ALREADY STREAMED ACRS THE TAF SITES ALONG WITH
SOME MID LEVEL CLOUDS AHEAD OF AN APPROACHING COLD FRONT. OVERALL
CLOUDS WILL THICKEN AND LOWER THIS AFTERNOON AND EVENING AS THE
COLD FRONT MOVES INTO THE REGION BRINGING CHANCE OF SNOW SHOWERS
TO THE AREA...MAINLY AFTER 00Z/THU. KEEPING VFR CONDITIONS WITH
VCSH UNTIL AROUND 06Z...WHEN MANY AREAS SHOULD SEE SOME
INTERMITTENT SNOW OR SNOW SHOWERS. MVFR CEILINGS AND VISIBILITIES
SHOULD ACCOMPANY THE SNOW LOWERING TO IFR CONDITIONS THURSDAY
MORNING. WINDS CALM TO LIGHT AND VARIABLE THROUGH 06Z AND THEN
BCMG NORTHWEST 10-14KTS THURSDAY MORNING.
OUTLOOK...
WED NIGHT-THU: MODERATE OPERATIONAL IMPACT. CHC -SHSN.
THU NIGHT-FRI NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
SAT-SUN: MODERATE OPERATIONAL IMPACT. CHC SN.
&&
.HYDROLOGY...
ICE WILL CONTINUE TO THICKEN ON AREA RIVERS...STREAMS...LAKES...AND
PONDS...AS CONTINUED BELOW NORMAL TEMPERATURES REMAIN IN PLACE
THROUGH THE REMAINDER OF THE WEEK. TEMPERATURES LOOK TO STAY BELOW
FREEZING THROUGH SATURDAY.
ANY PRECIP...ALL IN THE FORM OF SNOW...WILL BE FAIRLY LIGHT OVER
THE NEXT FEW DAYS. SOME SNOW SHOWERS ARE POSSIBLE BETWEEN TODAY
AND TOMORROW...BUT THIS WILL HAVE LITTLE TO NO IMMEDIATE IMPACT ON
AREA WATERWAYS. SOME GAGES WILL EXPERIENCE ICE EFFECTS...AND SOME
ERRONEOUS DATA MAY BE SEEN FROM TIME TO TIME.
A STORM SYSTEM WILL IMPACT THE REGION OVER THE WEEKEND WITH SOME
ADDITIONAL PRECIPITATION...MAINLY ON SUNDAY. IT IS STILL UNCLEAR
IN WHAT FORM THIS PRECIP WILL BE /RAIN...SNOW...OR MIXED
PRECIPITATION/ AND EXACT AMOUNTS ARE STILL FAR FROM CERTAIN. WE
WILL NEED TO MONITOR THE POTENTIAL FOR HOW THIS STORM MAY IMPACT
THE HYDROLOGIC AREA.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING
OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE
VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON
OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...FRUGIS/HWJIV
NEAR TERM...FRUGIS/HWJIV/11
SHORT TERM...FRUGIS
LONG TERM...NAS
AVIATION...11/NAS
HYDROLOGY...FRUGIS
AREA FORECAST DISCUSSION
NWS ALBANY NY
1234 PM EST WED FEB 18 2015
.SYNOPSIS...
CLOUDS WILL INCREASE THROUGH THE DAY AHEAD OF AN
APPROACHING ARCTIC COLD FRONT. THIS FRONT WILL BRING SOME SNOW
SHOWERS AND SNOW SQUALLS TO THE REGION THIS EVENING INTO TONIGHT.
BITTER COLD TEMPERATURES...ALONG WITH A FEW ADDITIONAL SNOW
SHOWERS...WILL BE IN PLACE ACROSS THE REGION FOR THURSDAY INTO
FRIDAY. ANOTHER STORM SYSTEM WILL IMPACT THE AREA OVER THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 915 AM EST...A STRONG SHORTWAVE AND ASSOCIATED SFC COLD
FRONT IS SITUATED UPSTREAM OF THE REGION OVER THE GREAT LAKES.
SOME MID AND HIGH LEVEL CLOUDS HAVE STARTED TO MOVE INTO OUR
AREA...BUT THE MAJORITY OF THESE CLOUDS HAVE BEEN RATHER THIN.
WITH A DEEP SNOWPACK AND LIGHT WINDS IN PLACE...TEMPS HAVE BEEN
VERY COLD SO FAR THIS MORNING...WITH MOST AREAS ONLY IN THE SINGLE
DIGITS TO SLIGHTLY BELOW ZERO.
CLOUDS WILL CONTINUE TO LOWER AND THICKEN THROUGHOUT THE DAY AS
THE ARCTIC FRONT CONTINUES TO MOVE EASTWARD TOWARDS THE AREA. MOST
AREAS LOOK TO BE MOSTLY CLOUDY BY AFTERNOON. IT SHOULD STAY DRY
ACROSS THE REGION THROUGH THE EARLY EVENING...AS THE LATEST 09Z
3KM HRRR SHOWS A BAND OF HEAVY SNOW SHOWERS STILL BACK OVER CNY
BETWEEN THE FINGER LAKES AND THE SYRACUSE AREA BY ABOUT 5-6 PM.
WILL START TO RAISE POPS FOR WESTERN AREAS FOR THE LATE AFTN/EARLY
EVENING IN CASE THIS SPEEDS UP...BUT MOST AREAS WON/T SEE ANY SNOW
UNTIL TONIGHT.
HIGH TEMPS TODAY WILL BE A LITTLE WARMER THAN TUESDAY...BUT STILL
BELOW NORMAL...WITH TEMPS RANGING FROM THE MID TEENS IN THE
ADIRONDACKS TO THE MID 20S IN THE HUDSON VALLEY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
THE ARCTIC COLD FRONT WILL BE PASSING FROM WEST TO EAST ACROSS THE
REGION TONIGHT. THE FRONT WILL BE SLOWED IN ITS PROGRESS...AS A
WEAK WAVE OF LOW PRESSURE DEVELOPS ALONG THE COLD/OCCLUDED
BOUNDARY. THE 00Z WFO BTV 4KM WRF SHOWS AN AREA OF SNOW SHOWERS
AND EMBEDDED SQUALLS IMPACTING THE REGION FROM WEST TO EAST DURING
THE OVERNIGHT HOURS. THE 00Z/06Z NAM ALSO SUGGESTS THIS WILL
OCCUR...ALTHOUGH THERE ARE SOME SLIGHT DIFFERENCES IN THE TIMING
DUE TO THE SLOW NATURE OF THE FRONTAL BOUNDARY. HAVE RAISED POPS
TO LIKELY FOR A FEW HOURS IN MOST LOCATIONS...WITH A LIGHT
ACCUMULATION OF 1-3 INCHES EXPECTED TONIGHT INTO THURSDAY
MORNING...WITH THE HIGHEST AMOUNTS FOR THE HIGHER ELEVATIONS. ALTHOUGH
QPF AMOUNTS ARE LIGHT...RATIOS ARE EXPECTED TO BE RATHER HIGH...AS
THE NAM BUFKIT SOUNDING SHOWS GOOD LIFT /OMEGA/ THROUGH THE
OPTIMAL DENDRITIC SNOW GROWTH LAYER. TEMPS LOOK TO COOL OFF
QUICKLY BEHIND THE BOUNDARY...WITH MINS LOWEST FOR WESTERN AREAS
/ZERO TO 5/ AND HIGHEST FOR EASTERN/SOUTHERN AREAS /GENERALLY 10
TO 15/.
WIDESPREAD SNOW SHOWERS WILL BE ONGOING THURSDAY MORNING...BUT
WILL BE TAPERING OFF BY MIDDAY FOR MOST AREAS...AS THE FRONT
CONTINUES TO PUSH EASTWARD...AND THE WAVE ON THE BOUNDARY RE-
DEVELOPS AND RAPIDLY STRENGTHENS OFF THE EASTERN NEW ENGLAND
COAST. TEMPS WON/T RISE TOO MUCH ON THURSDAY WITH THE STRONG COLD
AIR ADVECTION IN PLACE...AS 850 HPA TEMPS FALL TO -20 TO -25
DEGREES C. HIGHS WILL ONLY REACH THE SINGLE DIGITS TO MID TEENS.
SOME ADDITIONAL UPSLOPE SNOW MAY OCCUR WITH IN THE NW FLOW FOR
THE HIGH TERRAIN AREAS OF WESTERN NEW ENGLAND...AND SOME LAKE
ENHANCED SNOW SHOWERS COULD ALSO BE OCCURRING INTO THE MOHAWK
VALLEY/SCHOHARIE COUNTY THANKS TO THE FLOW MOVING ACROSS LAKE
ONTARIO. SOME ADDITIONAL ACCUMULATION OF AN INCH OR TWO IS
POSSIBLE FOR THESE AREAS.
WINDS WILL BE STARTING TO PICK UP BY THURSDAY AFTERNOON THANKS TO
THE INCREASING PRESSURE GRADIENT...AND WILL BE GUSTING 20-30 MPH
AT TIMES. THIS LOOK TO CONTINUE INTO THURSDAY NIGHT AS WELL...AND
TEMPS WILL BE FALLING TO ZERO TO -15 DEGREES F FOR LOW TEMPS FOR
THURSDAY NIGHT. WITH THE STRONG WINDS AND COLD TEMPS...WIND
CHILLS WILL CERTAINLY BE AN ISSUE. ADVISORY LEVEL WIND CHILLS
APPEAR LIKELY FOR MOST AREAS...AND A FEW SPOTS IN THE
ADIRONDACKS/CATSKILLS COULD POTENTIALLY REACH WARNING LEVELS AS
WELL. WILL CONTINUE TO HIGHLIGHT THESE THREATS IN THE HWO
STATEMENT. OUTSIDE OF THE BRUTALLY COLD TEMPS...SOME LINGERING
HIGH TERRAIN SNOW SHOWERS/FLURRIES ARE POSSIBLE...ALTHOUGH NOT
MUCH ADDITIONAL ACCUMULATION IS EXPECTED.
BITTER COLD TEMPS AND LOW WIND CHILL WILL REMAIN IN PLACE FOR
FRIDAY...ALTHOUGH WINDS WILL START TO REDUCE BY LATER IN THE DAY.
OUTSIDE A FEW FLURRIES/SNOW SHOWERS FOR THE WESTERN
ADIRONDACKS...NO PRECIP IS EXPECTED. MAX TEMPS WILL ONLY REACH THE
SINGLE DIGITS TO LOW TEENS...WITH A FEW SPOTS IN THE HIGH TERRAIN
REMAINING BELOW ZERO.
ANOTHER BITTER COLD NIGHT IS EXPECTED FOR FRIDAY NIGHT...BUT WIND
CHILLS WON/T BE AN ADDITIONAL CONCERN THANKS TO A LIGHT TO CALM
WINDS. STILL...TEMPS WILL BE VERY COLD...WITH MOST AREAS BELOW
ZERO ONCE AGAIN...AND SOME HIGH TERRAIN LOCATIONS -10 TO -20
DEGREES F. IT SHOULD REMAIN DRY...WITH A PARTLY TO MOSTLY CLEAR
SKY...AS HIGH PRESSURE SLIDES BY TO THE SOUTH OF THE AREA.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
APPROACHING UPPER ENERGY WILL RESULT IN THICKENING CLOUDS AND SLOWLY
INCREASING COVERAGE OF LIGHT SNOW. WARM ADVECTION WILL INCREASE...
AS WILL ISENTROPIC LIFT. SO HIGHS SATURDAY IN THE UPPER TEENS TO MID
20S...WITH JUST CHANCES FOR LIGHT SNOW IN THE AFTERNOON.
COVERAGE OF PRECIPITATION WILL INCREASE SATURDAY NIGHT INTO
SUNDAY...AS WILL WARM ADVECTION AND ISENTROPIC LIFT. LOW LEVEL JET
ENERGY WILL SPREAD NORTH AND EAST...ENHANCING THE WARM ADVECTION...
ESPECIALLY SUNDAY. THERE ARE SOME CONFLICTS COMPARING DETERMINISTIC
GUIDANCE AND ENSEMBLE GUIDANCE. DETERMINISTIC GUIDANCE SUGGESTS A
PRECIPITATION TRANSITION TO MIXED PRECIPITATION OR COLD RAIN FOR THE
MUCH OF THE FORECAST AREA SUNDAY...WHILE ENSEMBLE MEAN THERMAL
PROFILES SUGGEST THE DETERMINISTIC GUIDANCE IS ON THE WARMER SIDE OF
THE ENSEMBLE RANGE.
THE MEAN EASTERN NORTH AMERICAN UPPER TROUGH WILL HAVE TO RETROGRADE
QUITE A BIT FOR ENOUGH WARM AIR TO FLOOD THE EASTERN U.S. TO BRING
RAIN DURING AN OTHERWISE SNOWY AND COLD WINTER. THERE IS STILL LOTS
OF TIME TO WATCH THE DEVELOPMENT OF THIS SYSTEM...AND UNTIL THERE
ARE CLEAR SIGNALS FOR MIXED PRECIPITATION OR COLD RAIN...WILL
INDICATE SNOW IN MOST AREAS THROUGH SUNDAY...WITH THE EXCEPTION OF
PARTS OF THE EASTERN CATSKILLS...MID HUDSON VALLEY AND NW CT...WHERE
RAIN AND SNOW WILL BE INDICATED. HIGHS SUNDAY AROUND 30 TO THE MID
30S...MID TO UPPER 20S NORTHERN AREAS.
ONCE THE SYSTEM EXITS SUNDAY NIGHT...ANOTHER PUSH OF VERY COLD AIR
SPILLS INTO THE REGION...WITH MUCH BELOW NORMAL TEMPERATURES. HIGHS
MONDAY IN THE TEENS TO LOWER 20S...SOME UPPER SINGLE NUMBERS IN THE
SOUTHERN ADIRONDACKS. HIGHS TUESDAY IN THE MID TEENS TO LOWER 20S.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
CIRRUS CLOUDS HAVE ALREADY STREAMED ACRS THE TAF SITES ALONG WITH
SOME MID LEVEL CLOUDS AHEAD OF AN APPROACHING COLD FRONT. OVERALL
CLOUDS WILL THICKEN AND LOWER THIS AFTERNOON AND EVENING AS THE
COLD FRONT MOVES INTO THE REGION BRINGING CHANCE OF SNOW SHOWERS
TO THE AREA...MAINLY AFTER 00Z/THU. KEEPING VFR CONDITIONS WITH
VCSH UNTIL AROUND 06Z...WHEN MANY AREAS SHOULD SEE SOME
INTERMITTENT SNOW OR SNOW SHOWERS. MVFR CEILINGS AND VISIBILITIES
SHOULD ACCOMPANY THE SNOW LOWERING TO IFR CONDITIONS THURSDAY
MORNING. WINDS CALM TO LIGHT AND VARIABLE THROUGH 06Z AND THEN
BCMG NORTHWEST 10-14KTS THURSDAY MORNING.
OUTLOOK...
WED NIGHT-THU: MODERATE OPERATIONAL IMPACT. CHC -SHSN.
THU NIGHT-FRI NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
SAT-SUN: MODERATE OPERATIONAL IMPACT. CHC SN.
&&
.HYDROLOGY...
ICE WILL CONTINUE TO THICKEN ON AREA RIVERS...STREAMS...LAKES...AND
PONDS...AS CONTINUED BELOW NORMAL TEMPERATURES REMAIN IN PLACE
THROUGH THE REMAINDER OF THE WEEK. TEMPERATURES LOOK TO STAY BELOW
FREEZING THROUGH SATURDAY.
ANY PRECIP...ALL IN THE FORM OF SNOW...WILL BE FAIRLY LIGHT OVER
THE NEXT FEW DAYS. SOME SNOW SHOWERS ARE POSSIBLE BETWEEN TODAY
AND TOMORROW...BUT THIS WILL HAVE LITTLE TO NO IMMEDIATE IMPACT ON
AREA WATERWAYS. SOME GAGES WILL EXPERIENCE ICE EFFECTS...AND SOME
ERRONEOUS DATA MAY BE SEEN FROM TIME TO TIME.
A STORM SYSTEM WILL IMPACT THE REGION OVER THE WEEKEND WITH SOME
ADDITIONAL PRECIPITATION...MAINLY ON SUNDAY. IT IS STILL UNCLEAR
IN WHAT FORM THIS PRECIP WILL BE /RAIN...SNOW...OR MIXED
PRECIPITATION/ AND EXACT AMOUNTS ARE STILL FAR FROM CERTAIN. WE
WILL NEED TO MONITOR THE POTENTIAL FOR HOW THIS STORM MAY IMPACT
THE HYDROLOGIC AREA.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING
OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE
VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON
OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...FRUGIS/HWJIV
NEAR TERM...FRUGIS/HWJIV/11
SHORT TERM...FRUGIS
LONG TERM...NAS
AVIATION...11/NAS
HYDROLOGY...FRUGIS
AREA FORECAST DISCUSSION
NWS ALBANY NY
1211 PM EST WED FEB 18 2015
.SYNOPSIS...
CLOUDS WILL INCREASE THROUGH THE DAY AHEAD OF AN
APPROACHING ARCTIC COLD FRONT. THIS FRONT WILL BRING SOME SNOW
SHOWERS AND SNOW SQUALLS TO THE REGION THIS EVENING INTO TONIGHT.
BITTER COLD TEMPERATURES...ALONG WITH A FEW ADDITIONAL SNOW
SHOWERS...WILL BE IN PLACE ACROSS THE REGION FOR THURSDAY INTO
FRIDAY. ANOTHER STORM SYSTEM WILL IMPACT THE AREA OVER THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 915 AM EST...A STRONG SHORTWAVE AND ASSOCIATED SFC COLD
FRONT IS SITUATED UPSTREAM OF THE REGION OVER THE GREAT LAKES.
SOME MID AND HIGH LEVEL CLOUDS HAVE STARTED TO MOVE INTO OUR
AREA...BUT THE MAJORITY OF THESE CLOUDS HAVE BEEN RATHER THIN.
WITH A DEEP SNOWPACK AND LIGHT WINDS IN PLACE...TEMPS HAVE BEEN
VERY COLD SO FAR THIS MORNING...WITH MOST AREAS ONLY IN THE SINGLE
DIGITS TO SLIGHTLY BELOW ZERO.
CLOUDS WILL CONTINUE TO LOWER AND THICKEN THROUGHOUT THE DAY AS
THE ARCTIC FRONT CONTINUES TO MOVE EASTWARD TOWARDS THE AREA. MOST
AREAS LOOK TO BE MOSTLY CLOUDY BY AFTERNOON. IT SHOULD STAY DRY
ACROSS THE REGION THROUGH THE EARLY EVENING...AS THE LATEST 09Z
3KM HRRR SHOWS A BAND OF HEAVY SNOW SHOWERS STILL BACK OVER CNY
BETWEEN THE FINGER LAKES AND THE SYRACUSE AREA BY ABOUT 5-6 PM.
WILL START TO RAISE POPS FOR WESTERN AREAS FOR THE LATE AFTN/EARLY
EVENING IN CASE THIS SPEEDS UP...BUT MOST AREAS WON/T SEE ANY SNOW
UNTIL TONIGHT.
HIGH TEMPS TODAY WILL BE A LITTLE WARMER THAN TUESDAY...BUT STILL
BELOW NORMAL...WITH TEMPS RANGING FROM THE MID TEENS IN THE
ADIRONDACKS TO THE MID 20S IN THE HUDSON VALLEY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
THE ARCTIC COLD FRONT WILL BE PASSING FROM WEST TO EAST ACROSS THE
REGION TONIGHT. THE FRONT WILL BE SLOWED IN ITS PROGRESS...AS A
WEAK WAVE OF LOW PRESSURE DEVELOPS ALONG THE COLD/OCCLUDED
BOUNDARY. THE 00Z WFO BTV 4KM WRF SHOWS AN AREA OF SNOW SHOWERS
AND EMBEDDED SQUALLS IMPACTING THE REGION FROM WEST TO EAST DURING
THE OVERNIGHT HOURS. THE 00Z/06Z NAM ALSO SUGGESTS THIS WILL
OCCUR...ALTHOUGH THERE ARE SOME SLIGHT DIFFERENCES IN THE TIMING
DUE TO THE SLOW NATURE OF THE FRONTAL BOUNDARY. HAVE RAISED POPS
TO LIKELY FOR A FEW HOURS IN MOST LOCATIONS...WITH A LIGHT
ACCUMULATION OF 1-3 INCHES EXPECTED TONIGHT INTO THURSDAY
MORNING...WITH THE HIGHEST AMOUNTS FOR THE HIGHER ELEVATIONS. ALTHOUGH
QPF AMOUNTS ARE LIGHT...RATIOS ARE EXPECTED TO BE RATHER HIGH...AS
THE NAM BUFKIT SOUNDING SHOWS GOOD LIFT /OMEGA/ THROUGH THE
OPTIMAL DENDRITIC SNOW GROWTH LAYER. TEMPS LOOK TO COOL OFF
QUICKLY BEHIND THE BOUNDARY...WITH MINS LOWEST FOR WESTERN AREAS
/ZERO TO 5/ AND HIGHEST FOR EASTERN/SOUTHERN AREAS /GENERALLY 10
TO 15/.
WIDESPREAD SNOW SHOWERS WILL BE ONGOING THURSDAY MORNING...BUT
WILL BE TAPERING OFF BY MIDDAY FOR MOST AREAS...AS THE FRONT
CONTINUES TO PUSH EASTWARD...AND THE WAVE ON THE BOUNDARY RE-
DEVELOPS AND RAPIDLY STRENGTHENS OFF THE EASTERN NEW ENGLAND
COAST. TEMPS WON/T RISE TOO MUCH ON THURSDAY WITH THE STRONG COLD
AIR ADVECTION IN PLACE...AS 850 HPA TEMPS FALL TO -20 TO -25
DEGREES C. HIGHS WILL ONLY REACH THE SINGLE DIGITS TO MID TEENS.
SOME ADDITIONAL UPSLOPE SNOW MAY OCCUR WITH IN THE NW FLOW FOR
THE HIGH TERRAIN AREAS OF WESTERN NEW ENGLAND...AND SOME LAKE
ENHANCED SNOW SHOWERS COULD ALSO BE OCCURRING INTO THE MOHAWK
VALLEY/SCHOHARIE COUNTY THANKS TO THE FLOW MOVING ACROSS LAKE
ONTARIO. SOME ADDITIONAL ACCUMULATION OF AN INCH OR TWO IS
POSSIBLE FOR THESE AREAS.
WINDS WILL BE STARTING TO PICK UP BY THURSDAY AFTERNOON THANKS TO
THE INCREASING PRESSURE GRADIENT...AND WILL BE GUSTING 20-30 MPH
AT TIMES. THIS LOOK TO CONTINUE INTO THURSDAY NIGHT AS WELL...AND
TEMPS WILL BE FALLING TO ZERO TO -15 DEGREES F FOR LOW TEMPS FOR
THURSDAY NIGHT. WITH THE STRONG WINDS AND COLD TEMPS...WIND
CHILLS WILL CERTAINLY BE AN ISSUE. ADVISORY LEVEL WIND CHILLS
APPEAR LIKELY FOR MOST AREAS...AND A FEW SPOTS IN THE
ADIRONDACKS/CATSKILLS COULD POTENTIALLY REACH WARNING LEVELS AS
WELL. WILL CONTINUE TO HIGHLIGHT THESE THREATS IN THE HWO
STATEMENT. OUTSIDE OF THE BRUTALLY COLD TEMPS...SOME LINGERING
HIGH TERRAIN SNOW SHOWERS/FLURRIES ARE POSSIBLE...ALTHOUGH NOT
MUCH ADDITIONAL ACCUMULATION IS EXPECTED.
BITTER COLD TEMPS AND LOW WIND CHILL WILL REMAIN IN PLACE FOR
FRIDAY...ALTHOUGH WINDS WILL START TO REDUCE BY LATER IN THE DAY.
OUTSIDE A FEW FLURRIES/SNOW SHOWERS FOR THE WESTERN
ADIRONDACKS...NO PRECIP IS EXPECTED. MAX TEMPS WILL ONLY REACH THE
SINGLE DIGITS TO LOW TEENS...WITH A FEW SPOTS IN THE HIGH TERRAIN
REMAINING BELOW ZERO.
ANOTHER BITTER COLD NIGHT IS EXPECTED FOR FRIDAY NIGHT...BUT WIND
CHILLS WON/T BE AN ADDITIONAL CONCERN THANKS TO A LIGHT TO CALM
WINDS. STILL...TEMPS WILL BE VERY COLD...WITH MOST AREAS BELOW
ZERO ONCE AGAIN...AND SOME HIGH TERRAIN LOCATIONS -10 TO -20
DEGREES F. IT SHOULD REMAIN DRY...WITH A PARTLY TO MOSTLY CLEAR
SKY...AS HIGH PRESSURE SLIDES BY TO THE SOUTH OF THE AREA.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
APPROACHING UPPER ENERGY WILL RESULT IN THICKENING CLOUDS AND SLOWLY
INCREASING COVERAGE OF LIGHT SNOW. WARM ADVECTION WILL INCREASE...
AS WILL ISENTROPIC LIFT. SO HIGHS SATURDAY IN THE UPPER TEENS TO MID
20S...WITH JUST CHANCES FOR LIGHT SNOW IN THE AFTERNOON.
COVERAGE OF PRECIPITATION WILL INCREASE SATURDAY NIGHT INTO
SUNDAY...AS WILL WARM ADVECTION AND ISENTROPIC LIFT. LOW LEVEL JET
ENERGY WILL SPREAD NORTH AND EAST...ENHANCING THE WARM ADVECTION...
ESPECIALLY SUNDAY. THERE ARE SOME CONFLICTS COMPARING DETERMINISTIC
GUIDANCE AND ENSEMBLE GUIDANCE. DETERMINISTIC GUIDANCE SUGGESTS A
PRECIPITATION TRANSITION TO MIXED PRECIPITATION OR COLD RAIN FOR THE
MUCH OF THE FORECAST AREA SUNDAY...WHILE ENSEMBLE MEAN THERMAL
PROFILES SUGGEST THE DETERMINISTIC GUIDANCE IS ON THE WARMER SIDE OF
THE ENSEMBLE RANGE.
THE MEAN EASTERN NORTH AMERICAN UPPER TROUGH WILL HAVE TO RETROGRADE
QUITE A BIT FOR ENOUGH WARM AIR TO FLOOD THE EASTERN U.S. TO BRING
RAIN DURING AN OTHERWISE SNOWY AND COLD WINTER. THERE IS STILL LOTS
OF TIME TO WATCH THE DEVELOPMENT OF THIS SYSTEM...AND UNTIL THERE
ARE CLEAR SIGNALS FOR MIXED PRECIPITATION OR COLD RAIN...WILL
INDICATE SNOW IN MOST AREAS THROUGH SUNDAY...WITH THE EXCEPTION OF
PARTS OF THE EASTERN CATSKILLS...MID HUDSON VALLEY AND NW CT...WHERE
RAIN AND SNOW WILL BE INDICATED. HIGHS SUNDAY AROUND 30 TO THE MID
30S...MID TO UPPER 20S NORTHERN AREAS.
ONCE THE SYSTEM EXITS SUNDAY NIGHT...ANOTHER PUSH OF VERY COLD AIR
SPILLS INTO THE REGION...WITH MUCH BELOW NORMAL TEMPERATURES. HIGHS
MONDAY IN THE TEENS TO LOWER 20S...SOME UPPER SINGLE NUMBERS IN THE
SOUTHERN ADIRONDACKS. HIGHS TUESDAY IN THE MID TEENS TO LOWER 20S.
&&
.AVIATION /17Z WEDNESDAY THROUGH SUNDAY/...
CIRRUS CLOUDS HAVE ALREADY STREAMED ACRS THE TAF SITES ALONG WITH
SOME MID LEVEL CLOUDS AHEAD OF AN APPROACHING COLD FRONT. OVERALL
CLOUDS WILL THICKEN AND LOWER THIS AFTERNOON AND EVENING AS THE
COLD FRONT MOVES INTO THE REGION BRINGING CHANCE OF SNOW SHOWERS
TO THE AREA...MAINLY AFTER 00Z/THU. KEEPING VFR CONDITIONS WITH
VCSH UNTIL AROUND 06Z...WHEN MANY AREAS SHOULD SEE SOME
INTERMITTENT SNOW OR SNOW SHOWERS. MVFR CEILINGS AND VISIBILITIES
SHOULD ACCOMPANY THE SNOW LOWERING TO IFR CONDITIONS THURSDAY
MORNING. WINDS CALM TO LIGHT AND VARIABLE THROUGH 06Z AND THEN
BCMG NORTHWEST 10-14KTS THURSDAY MORNING.
OUTLOOK...
WED NIGHT-THU: MODERATE OPERATIONAL IMPACT. CHC -SHSN.
THU NIGHT-FRI NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
SAT-SUN: MODERATE OPERATIONAL IMPACT. CHC SN.
&&
.HYDROLOGY...
ICE WILL CONTINUE TO THICKEN ON AREA RIVERS...STREAMS...LAKES...AND
PONDS...AS CONTINUED BELOW NORMAL TEMPERATURES REMAIN IN PLACE
THROUGH THE REMAINDER OF THE WEEK. TEMPERATURES LOOK TO STAY BELOW
FREEZING THROUGH SATURDAY.
ANY PRECIP...ALL IN THE FORM OF SNOW...WILL BE FAIRLY LIGHT OVER
THE NEXT FEW DAYS. SOME SNOW SHOWERS ARE POSSIBLE BETWEEN TODAY
AND TOMORROW...BUT THIS WILL HAVE LITTLE TO NO IMMEDIATE IMPACT ON
AREA WATERWAYS. SOME GAGES WILL EXPERIENCE ICE EFFECTS...AND SOME
ERRONEOUS DATA MAY BE SEEN FROM TIME TO TIME.
A STORM SYSTEM WILL IMPACT THE REGION OVER THE WEEKEND WITH SOME
ADDITIONAL PRECIPITATION...MAINLY ON SUNDAY. IT IS STILL UNCLEAR
IN WHAT FORM THIS PRECIP WILL BE /RAIN...SNOW...OR MIXED
PRECIPITATION/ AND EXACT AMOUNTS ARE STILL FAR FROM CERTAIN. WE
WILL NEED TO MONITOR THE POTENTIAL FOR HOW THIS STORM MAY IMPACT
THE HYDROLOGIC AREA.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING
OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE
VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON
OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...FRUGIS
NEAR TERM...FRUGIS/11
SHORT TERM...FRUGIS
LONG TERM...NAS
AVIATION...11/NAS
HYDROLOGY...FRUGIS
AREA FORECAST DISCUSSION
NWS ALBANY NY
916 AM EST WED FEB 18 2015
.SYNOPSIS...
CLOUDS WILL INCREASE THROUGH THE DAY AHEAD OF AN
APPROACHING ARCTIC COLD FRONT. THIS FRONT WILL BRING SOME SNOW
SHOWERS AND SNOW SQUALLS TO THE REGION THIS EVENING INTO TONIGHT.
BITTER COLD TEMPERATURES...ALONG WITH A FEW ADDITIONAL SNOW
SHOWERS...WILL BE IN PLACE ACROSS THE REGION FOR THURSDAY INTO
FRIDAY. ANOTHER STORM SYSTEM WILL IMPACT THE AREA OVER THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 915 AM EST...A STRONG SHORTWAVE AND ASSOCIATED SFC COLD
FRONT IS SITUATED UPSTREAM OF THE REGION OVER THE GREAT LAKES.
SOME MID AND HIGH LEVEL CLOUDS HAVE STARTED TO MOVE INTO OUR
AREA...BUT THE MAJORITY OF THESE CLOUDS HAVE BEEN RATHER THIN.
WITH A DEEP SNOWPACK AND LIGHT WINDS IN PLACE...TEMPS HAVE BEEN
VERY COLD SO FAR THIS MORNING...WITH MOST AREAS ONLY IN THE SINGLE
DIGITS TO SLIGHTLY BELOW ZERO.
CLOUDS WILL CONTINUE TO LOWER AND THICKEN THROUGHOUT THE DAY AS
THE ARCTIC FRONT CONTINUES TO MOVE EASTWARD TOWARDS THE AREA. MOST
AREAS LOOK TO BE MOSTLY CLOUDY BY AFTERNOON. IT SHOULD STAY DRY
ACROSS THE REGION THROUGH THE EARLY EVENING...AS THE LATEST 09Z
3KM HRRR SHOWS A BAND OF HEAVY SNOW SHOWERS STILL BACK OVER CNY
BETWEEN THE FINGER LAKES AND THE SYRACUSE AREA BY ABOUT 5-6 PM.
WILL START TO RAISE POPS FOR WESTERN AREAS FOR THE LATE AFTN/EARLY
EVENING IN CASE THIS SPEEDS UP...BUT MOST AREAS WON/T SEE ANY SNOW
UNTIL TONIGHT.
HIGH TEMPS TODAY WILL BE A LITTLE WARMER THAN TUESDAY...BUT STILL
BELOW NORMAL...WITH TEMPS RANGING FROM THE MID TEENS IN THE
ADIRONDACKS TO THE MID 20S IN THE HUDSON VALLEY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
THE ARCTIC COLD FRONT WILL BE PASSING FROM WEST TO EAST ACROSS THE
REGION TONIGHT. THE FRONT WILL BE SLOWED IN ITS PROGRESS...AS A
WEAK WAVE OF LOW PRESSURE DEVELOPS ALONG THE COLD/OCCLUDED
BOUNDARY. THE 00Z WFO BTV 4KM WRF SHOWS AN AREA OF SNOW SHOWERS
AND EMBEDDED SQUALLS IMPACTING THE REGION FROM WEST TO EAST DURING
THE OVERNIGHT HOURS. THE 00Z/06Z NAM ALSO SUGGESTS THIS WILL
OCCUR...ALTHOUGH THERE ARE SOME SLIGHT DIFFERENCES IN THE TIMING
DUE TO THE SLOW NATURE OF THE FRONTAL BOUNDARY. HAVE RAISED POPS
TO LIKELY FOR A FEW HOURS IN MOST LOCATIONS...WITH A LIGHT
ACCUMULATION OF 1-3 INCHES EXPECTED TONIGHT INTO THURSDAY
MORNING...WITH THE HIGHEST AMOUNTS FOR THE HIGHER ELEVATIONS. ALTHOUGH
QPF AMOUNTS ARE LIGHT...RATIOS ARE EXPECTED TO BE RATHER HIGH...AS
THE NAM BUFKIT SOUNDING SHOWS GOOD LIFT /OMEGA/ THROUGH THE
OPTIMAL DENDRITIC SNOW GROWTH LAYER. TEMPS LOOK TO COOL OFF
QUICKLY BEHIND THE BOUNDARY...WITH MINS LOWEST FOR WESTERN AREAS
/ZERO TO 5/ AND HIGHEST FOR EASTERN/SOUTHERN AREAS /GENERALLY 10
TO 15/.
WIDESPREAD SNOW SHOWERS WILL BE ONGOING THURSDAY MORNING...BUT
WILL BE TAPERING OFF BY MIDDAY FOR MOST AREAS...AS THE FRONT
CONTINUES TO PUSH EASTWARD...AND THE WAVE ON THE BOUNDARY RE-
DEVELOPS AND RAPIDLY STRENGTHENS OFF THE EASTERN NEW ENGLAND
COAST. TEMPS WON/T RISE TOO MUCH ON THURSDAY WITH THE STRONG COLD
AIR ADVECTION IN PLACE...AS 850 HPA TEMPS FALL TO -20 TO -25
DEGREES C. HIGHS WILL ONLY REACH THE SINGLE DIGITS TO MID TEENS.
SOME ADDITIONAL UPSLOPE SNOW MAY OCCUR WITH IN THE NW FLOW FOR
THE HIGH TERRAIN AREAS OF WESTERN NEW ENGLAND...AND SOME LAKE
ENHANCED SNOW SHOWERS COULD ALSO BE OCCURRING INTO THE MOHAWK
VALLEY/SCHOHARIE COUNTY THANKS TO THE FLOW MOVING ACROSS LAKE
ONTARIO. SOME ADDITIONAL ACCUMULATION OF AN INCH OR TWO IS
POSSIBLE FOR THESE AREAS.
WINDS WILL BE STARTING TO PICK UP BY THURSDAY AFTERNOON THANKS TO
THE INCREASING PRESSURE GRADIENT...AND WILL BE GUSTING 20-30 MPH
AT TIMES. THIS LOOK TO CONTINUE INTO THURSDAY NIGHT AS WELL...AND
TEMPS WILL BE FALLING TO ZERO TO -15 DEGREES F FOR LOW TEMPS FOR
THURSDAY NIGHT. WITH THE STRONG WINDS AND COLD TEMPS...WIND CHILLS
WILL CERTAINLY BE AN ISSUE. ADVISORY LEVEL WIND CHILLS APPEAR
LIKELY FOR MOST AREAS...AND A FEW SPOTS IN THE
ADIRONDACKS/CATSKILLS COULD POTENTIALLY REACH WARNING LEVELS AS
WELL. WILL CONTINUE TO HIGHLIGHT THESE THREATS IN THE HWO
STATEMENT. OUTSIDE OF THE BRUTALLY COLD TEMPS...SOME LINGERING
HIGH TERRAIN SNOW SHOWERS/FLURRIES ARE POSSIBLE...ALTHOUGH NOT
MUCH ADDITIONAL ACCUMULATION IS EXPECTED.
BITTER COLD TEMPS AND LOW WIND CHILL WILL REMAIN IN PLACE FOR
FRIDAY...ALTHOUGH WINDS WILL START TO REDUCE BY LATER IN THE DAY.
OUTSIDE A FEW FLURRIES/SNOW SHOWERS FOR THE WESTERN
ADIRONDACKS...NO PRECIP IS EXPECTED. MAX TEMPS WILL ONLY REACH THE
SINGLE DIGITS TO LOW TEENS...WITH A FEW SPOTS IN THE HIGH TERRAIN
REMAINING BELOW ZERO.
ANOTHER BITTER COLD NIGHT IS EXPECTED FOR FRIDAY NIGHT...BUT WIND
CHILLS WON/T BE AN ADDITIONAL CONCERN THANKS TO A LIGHT TO CALM
WINDS. STILL...TEMPS WILL BE VERY COLD...WITH MOST AREAS BELOW
ZERO ONCE AGAIN...AND SOME HIGH TERRAIN LOCATIONS -10 TO -20
DEGREES F. IT SHOULD REMAIN DRY...WITH A PARTLY TO MOSTLY CLEAR
SKY...AS HIGH PRESSURE SLIDES BY TO THE SOUTH OF THE AREA.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
APPROACHING UPPER ENERGY WILL RESULT IN THICKENING CLOUDS AND SLOWLY
INCREASING COVERAGE OF LIGHT SNOW. WARM ADVECTION WILL INCREASE...
AS WILL ISENTROPIC LIFT. SO HIGHS SATURDAY IN THE UPPER TEENS TO MID
20S...WITH JUST CHANCES FOR LIGHT SNOW IN THE AFTERNOON.
COVERAGE OF PRECIPITATION WILL INCREASE SATURDAY NIGHT INTO
SUNDAY...AS WILL WARM ADVECTION AND ISENTROPIC LIFT. LOW LEVEL JET
ENERGY WILL SPREAD NORTH AND EAST...ENHANCING THE WARM ADVECTION...
ESPECIALLY SUNDAY. THERE ARE SOME CONFLICTS COMPARING DETERMINISTIC
GUIDANCE AND ENSEMBLE GUIDANCE. DETERMINISTIC GUIDANCE SUGGESTS A
PRECIPITATION TRANSITION TO MIXED PRECIPITATION OR COLD RAIN FOR THE
MUCH OF THE FORECAST AREA SUNDAY...WHILE ENSEMBLE MEAN THERMAL
PROFILES SUGGEST THE DETERMINISTIC GUIDANCE IS ON THE WARMER SIDE OF
THE ENSEMBLE RANGE.
THE MEAN EASTERN NORTH AMERICAN UPPER TROUGH WILL HAVE TO RETROGRADE
QUITE A BIT FOR ENOUGH WARM AIR TO FLOOD THE EASTERN U.S. TO BRING
RAIN DURING AN OTHERWISE SNOWY AND COLD WINTER. THERE IS STILL LOTS
OF TIME TO WATCH THE DEVELOPMENT OF THIS SYSTEM...AND UNTIL THERE
ARE CLEAR SIGNALS FOR MIXED PRECIPITATION OR COLD RAIN...WILL
INDICATE SNOW IN MOST AREAS THROUGH SUNDAY...WITH THE EXCEPTION OF
PARTS OF THE EASTERN CATSKILLS...MID HUDSON VALLEY AND NW CT...WHERE
RAIN AND SNOW WILL BE INDICATED. HIGHS SUNDAY AROUND 30 TO THE MID
30S...MID TO UPPER 20S NORTHERN AREAS.
ONCE THE SYSTEM EXITS SUNDAY NIGHT...ANOTHER PUSH OF VERY COLD AIR
SPILLS INTO THE REGION...WITH MUCH BELOW NORMAL TEMPERATURES. HIGHS
MONDAY IN THE TEENS TO LOWER 20S...SOME UPPER SINGLE NUMBERS IN THE
SOUTHERN ADIRONDACKS. HIGHS TUESDAY IN THE MID TEENS TO LOWER 20S.
&&
.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
CIRRUS CLOUDS WILL STREAM IN THROUGH THE DAY ALONG WITH SOME MID
LEVEL CLOUDS AHEAD OF AN APPROACHING COLD FRONT. OVERALL CLOUDS WILL
THICKEN AND LOWER THIS AFTERNOON AND EVENING AS THE COLD FRONT MOVES
INTO THE REGION BRINGING CHANCE OF SNOW SHOWERS TO THE AREA...MAINLY
AFTER 00Z/THU. KEEPING VFR CONDITIONS WITH VCSH UNTIL AROUND
06Z...WHEN MANY AREAS SHOULD SEE SOME INTERMITTENT SNOW OR SNOW
SHOWERS. MVFR CEILINGS AND VISIBILITIES SHOULD ACCOMPANY THE SNOW.
WINDS CALM TO LIGHT AND VARIABLE THROUGH THE PERIOD.
OUTLOOK... WED NIGHT-THU: MODERATE OPERATIONAL IMPACT. CHC -SHSN.
THU NIGHT-FRI NIGHT: NO OPERATIONAL IMPACT. NO SIG WX. SAT-SUN:
MODERATE OPERATIONAL IMPACT. CHC SN.
&&
.HYDROLOGY...
ICE WILL CONTINUE TO THICKEN ON AREA RIVERS...STREAMS...LAKES...AND
PONDS...AS CONTINUED BELOW NORMAL TEMPERATURES REMAIN IN PLACE
THROUGH THE REMAINDER OF THE WEEK. TEMPERATURES LOOK TO STAY BELOW
FREEZING THROUGH SATURDAY.
ANY PRECIP...ALL IN THE FORM OF SNOW...WILL BE FAIRLY LIGHT OVER
THE NEXT FEW DAYS. SOME SNOW SHOWERS ARE POSSIBLE BETWEEN TODAY
AND TOMORROW...BUT THIS WILL HAVE LITTLE TO NO IMMEDIATE IMPACT ON
AREA WATERWAYS. SOME GAGES WILL EXPERIENCE ICE EFFECTS...AND SOME
ERRONEOUS DATA MAY BE SEEN FROM TIME TO TIME.
A STORM SYSTEM WILL IMPACT THE REGION OVER THE WEEKEND WITH SOME
ADDITIONAL PRECIPITATION...MAINLY ON SUNDAY. IT IS STILL UNCLEAR
IN WHAT FORM THIS PRECIP WILL BE /RAIN...SNOW...OR MIXED
PRECIPITATION/ AND EXACT AMOUNTS ARE STILL FAR FROM CERTAIN. WE
WILL NEED TO MONITOR THE POTENTIAL FOR HOW THIS STORM MAY IMPACT
THE HYDROLOGIC AREA.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING
OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE
VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON
OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...FRUGIS
NEAR TERM...FRUGIS/11
SHORT TERM...FRUGIS
LONG TERM...NAS
AVIATION...NAS
HYDROLOGY...FRUGIS
AREA FORECAST DISCUSSION
NWS ALBANY NY
630 AM EST WED FEB 18 2015
.SYNOPSIS...
CLOUDS WILL INCREASE THROUGH THE DAY AHEAD OF AN
APPROACHING ARCTIC COLD FRONT. THIS FRONT WILL BRING SOME SNOW
SHOWERS AND SNOW SQUALLS TO THE REGION THIS EVENING INTO TONIGHT.
BITTER COLD TEMPERATURES...ALONG WITH A FEW ADDITIONAL SNOW
SHOWERS...WILL BE IN PLACE ACROSS THE REGION FOR THURSDAY INTO
FRIDAY. ANOTHER STORM SYSTEM WILL IMPACT THE AREA OVER THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 630 AM EST...A STRONG SHORTWAVE AND ASSOCIATED SFC COLD
FRONT IS SITUATED UPSTREAM OF THE REGION OVER THE GREAT LAKES.
SOME MID AND HIGH LEVEL CLOUDS HAVE STARTED TO MOVE INTO OUR
AREA...BUT THE MAJORITY OF THESE CLOUDS HAVE BEEN RATHER THIN.
WITH A DEEP SNOWPACK AND LIGHT WINDS IN PLACE...TEMPS HAVE BEEN
VERY COLD SO FAR THIS MORNING...WITH MOST AREAS BELOW ZERO...AND
SOME SPOTS IN THE ADIRONDACKS CLOSE TO -20 DEGREES F.
CLOUDS WILL CONTINUE TO LOWER AND THICKEN THROUGHOUT THE DAY AS
THE ARCTIC FRONT CONTINUES TO MOVE EASTWARD TOWARDS THE AREA. MOST
AREAS LOOK TO BE MOSTLY CLOUDY BY AFTERNOON. IT SHOULD STAY DRY
ACROSS THE REGION THROUGH THE EARLY EVENING...AS THE LATEST 09Z
3KM HRRR SHOWS A BAND OF HEAVY SNOW SHOWERS STILL BACK OVER CNY
BETWEEN THE FINGER LAKES AND THE SYRACUSE AREA BY ABOUT 5-6 PM.
WILL START TO RAISE POPS FOR WESTERN AREAS FOR THE LATE AFTN/EARLY
EVENING IN CASE THIS SPEEDS UP...BUT MOST AREAS WON/T SEE ANY SNOW
UNTIL TONIGHT.
HIGH TEMPS TODAY WILL BE A LITTLE WARMER THAN TUESDAY...BUT STILL
BELOW NORMAL...WITH TEMPS RANGING FROM THE MID TEENS IN THE
ADIRONDACKS TO THE MID 20S IN THE HUDSON VALLEY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
THE ARCTIC COLD FRONT WILL BE PASSING FROM WEST TO EAST ACROSS THE
REGION TONIGHT. THE FRONT WILL BE SLOWED IN ITS PROGRESS...AS A
WEAK WAVE OF LOW PRESSURE DEVELOPS ALONG THE COLD/OCCLUDED
BOUNDARY. THE 00Z WFO BTV 4KM WRF SHOWS AN AREA OF SNOW SHOWERS
AND EMBEDDED SQUALLS IMPACTING THE REGION FROM WEST TO EAST DURING
THE OVERNIGHT HOURS. THE 00Z/06Z NAM ALSO SUGGESTS THIS WILL
OCCUR...ALTHOUGH THERE ARE SOME SLIGHT DIFFERENCES IN THE TIMING
DUE TO THE SLOW NATURE OF THE FRONTAL BOUNDARY. HAVE RAISED POPS
TO LIKELY FOR A FEW HOURS IN MOST LOCATIONS...WITH A LIGHT
ACCUMULATION OF 1-3 INCHES EXPECTED TONIGHT INTO THURSDAY
MORNING...WITH THE HIGHEST AMOUNTS FOR THE HIGHER ELEVATIONS. ALTHOUGH
QPF AMOUNTS ARE LIGHT...RATIOS ARE EXPECTED TO BE RATHER HIGH...AS
THE NAM BUFKIT SOUNDING SHOWS GOOD LIFT /OMEGA/ THROUGH THE
OPTIMAL DENDRITIC SNOW GROWTH LAYER. TEMPS LOOK TO COOL OFF
QUICKLY BEHIND THE BOUNDARY...WITH MINS LOWEST FOR WESTERN AREAS
/ZERO TO 5/ AND HIGHEST FOR EASTERN/SOUTHERN AREAS /GENERALLY 10
TO 15/.
WIDESPREAD SNOW SHOWERS WILL BE ONGOING THURSDAY MORNING...BUT
WILL BE TAPERING OFF BY MIDDAY FOR MOST AREAS...AS THE FRONT
CONTINUES TO PUSH EASTWARD...AND THE WAVE ON THE BOUNDARY RE-
DEVELOPS AND RAPIDLY STRENGTHENS OFF THE EASTERN NEW ENGLAND
COAST. TEMPS WON/T RISE TOO MUCH ON THURSDAY WITH THE STRONG COLD
AIR ADVECTION IN PLACE...AS 850 HPA TEMPS FALL TO -20 TO -25
DEGREES C. HIGHS WILL ONLY REACH THE SINGLE DIGITS TO MID TEENS.
SOME ADDITIONAL UPSLOPE SNOW MAY OCCUR WITH IN THE NW FLOW FOR
THE HIGH TERRAIN AREAS OF WESTERN NEW ENGLAND...AND SOME LAKE
ENHANCED SNOW SHOWERS COULD ALSO BE OCCURRING INTO THE MOHAWK
VALLEY/SCHOHARIE COUNTY THANKS TO THE FLOW MOVING ACROSS LAKE
ONTARIO. SOME ADDITIONAL ACCUMULATION OF AN INCH OR TWO IS
POSSIBLE FOR THESE AREAS.
WINDS WILL BE STARTING TO PICK UP BY THURSDAY AFTERNOON THANKS TO
THE INCREASING PRESSURE GRADIENT...AND WILL BE GUSTING 20-30 MPH
AT TIMES. THIS LOOK TO CONTINUE INTO THURSDAY NIGHT AS WELL...AND
TEMPS WILL BE FALLING TO ZERO TO -15 DEGREES F FOR LOW TEMPS FOR
THURSDAY NIGHT. WITH THE STRONG WINDS AND COLD TEMPS...WIND CHILLS
WILL CERTAINLY BE AN ISSUE. ADVISORY LEVEL WIND CHILLS APPEAR
LIKELY FOR MOST AREAS...AND A FEW SPOTS IN THE
ADIRONDACKS/CATSKILLS COULD POTENTIALLY REACH WARNING LEVELS AS
WELL. WILL CONTINUE TO HIGHLIGHT THESE THREATS IN THE HWO
STATEMENT. OUTSIDE OF THE BRUTALLY COLD TEMPS...SOME LINGERING
HIGH TERRAIN SNOW SHOWERS/FLURRIES ARE POSSIBLE...ALTHOUGH NOT
MUCH ADDITIONAL ACCUMULATION IS EXPECTED.
BITTER COLD TEMPS AND LOW WIND CHILL WILL REMAIN IN PLACE FOR
FRIDAY...ALTHOUGH WINDS WILL START TO REDUCE BY LATER IN THE DAY.
OUTSIDE A FEW FLURRIES/SNOW SHOWERS FOR THE WESTERN
ADIRONDACKS...NO PRECIP IS EXPECTED. MAX TEMPS WILL ONLY REACH THE
SINGLE DIGITS TO LOW TEENS...WITH A FEW SPOTS IN THE HIGH TERRAIN
REMAINING BELOW ZERO.
ANOTHER BITTER COLD NIGHT IS EXPECTED FOR FRIDAY NIGHT...BUT WIND
CHILLS WON/T BE AN ADDITIONAL CONCERN THANKS TO A LIGHT TO CALM
WINDS. STILL...TEMPS WILL BE VERY COLD...WITH MOST AREAS BELOW
ZERO ONCE AGAIN...AND SOME HIGH TERRAIN LOCATIONS -10 TO -20
DEGREES F. IT SHOULD REMAIN DRY...WITH A PARTLY TO MOSTLY CLEAR
SKY...AS HIGH PRESSURE SLIDES BY TO THE SOUTH OF THE AREA.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
APPROACHING UPPER ENERGY WILL RESULT IN THICKENING CLOUDS AND SLOWLY
INCREASING COVERAGE OF LIGHT SNOW. WARM ADVECTION WILL INCREASE...
AS WILL ISENTROPIC LIFT. SO HIGHS SATURDAY IN THE UPPER TEENS TO MID
20S...WITH JUST CHANCES FOR LIGHT SNOW IN THE AFTERNOON.
COVERAGE OF PRECIPITATION WILL INCREASE SATURDAY NIGHT INTO
SUNDAY...AS WILL WARM ADVECTION AND ISENTROPIC LIFT. LOW LEVEL JET
ENERGY WILL SPREAD NORTH AND EAST...ENHANCING THE WARM ADVECTION...
ESPECIALLY SUNDAY. THERE ARE SOME CONFLICTS COMPARING DETERMINISTIC
GUIDANCE AND ENSEMBLE GUIDANCE. DETERMINISTIC GUIDANCE SUGGESTS A
PRECIPITATION TRANSITION TO MIXED PRECIPITATION OR COLD RAIN FOR THE
MUCH OF THE FORECAST AREA SUNDAY...WHILE ENSEMBLE MEAN THERMAL
PROFILES SUGGEST THE DETERMINISTIC GUIDANCE IS ON THE WARMER SIDE OF
THE ENSEMBLE RANGE.
THE MEAN EASTERN NORTH AMERICAN UPPER TROUGH WILL HAVE TO RETROGRADE
QUITE A BIT FOR ENOUGH WARM AIR TO FLOOD THE EASTERN U.S. TO BRING
RAIN DURING AN OTHERWISE SNOWY AND COLD WINTER. THERE IS STILL LOTS
OF TIME TO WATCH THE DEVELOPMENT OF THIS SYSTEM...AND UNTIL THERE
ARE CLEAR SIGNALS FOR MIXED PRECIPITATION OR COLD RAIN...WILL
INDICATE SNOW IN MOST AREAS THROUGH SUNDAY...WITH THE EXCEPTION OF
PARTS OF THE EASTERN CATSKILLS...MID HUDSON VALLEY AND NW CT...WHERE
RAIN AND SNOW WILL BE INDICATED. HIGHS SUNDAY AROUND 30 TO THE MID
30S...MID TO UPPER 20S NORTHERN AREAS.
ONCE THE SYSTEM EXITS SUNDAY NIGHT...ANOTHER PUSH OF VERY COLD AIR
SPILLS INTO THE REGION...WITH MUCH BELOW NORMAL TEMPERATURES. HIGHS
MONDAY IN THE TEENS TO LOWER 20S...SOME UPPER SINGLE NUMBERS IN THE
SOUTHERN ADIRONDACKS. HIGHS TUESDAY IN THE MID TEENS TO LOWER 20S.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
CIRRUS CLOUDS WILL STREAM IN THROUGH THE DAY ALONG WITH SOME MID
LEVEL CLOUDS AHEAD OF AN APPROACHING COLD FRONT. OVERALL CLOUDS WILL
THICKEN AND LOWER THIS AFTERNOON AND EVENING AS THE COLD FRONT MOVES
INTO THE REGION BRINGING CHANCE OF SNOW SHOWERS TO THE AREA...MAINLY
AFTER 00Z/THU. KEEPING VFR CONDITIONS WITH VCSH UNTIL AROUND
06Z...WHEN MANY AREAS SHOULD SEE SOME INTERMITTENT SNOW OR SNOW
SHOWERS. MVFR CEILINGS AND VISIBILITIES SHOULD ACCOMPANY THE SNOW.
WINDS CALM TO LIGHT AND VARIABLE THROUGH THE PERIOD.
OUTLOOK... WED NIGHT-THU: MODERATE OPERATIONAL IMPACT. CHC -SHSN.
THU NIGHT-FRI NIGHT: NO OPERATIONAL IMPACT. NO SIG WX. SAT-SUN:
MODERATE OPERATIONAL IMPACT. CHC SN.
&&
.HYDROLOGY...
ICE WILL CONTINUE TO THICKEN ON AREA RIVERS...STREAMS...LAKES...AND
PONDS...AS CONTINUED BELOW NORMAL TEMPERATURES REMAIN IN PLACE
THROUGH THE REMAINDER OF THE WEEK. TEMPERATURES LOOK TO STAY BELOW
FREEZING THROUGH SATURDAY.
ANY PRECIP...ALL IN THE FORM OF SNOW...WILL BE FAIRLY LIGHT OVER
THE NEXT FEW DAYS. SOME SNOW SHOWERS ARE POSSIBLE BETWEEN TODAY
AND TOMORROW...BUT THIS WILL HAVE LITTLE TO NO IMMEDIATE IMPACT ON
AREA WATERWAYS. SOME GAGES WILL EXPERIENCE ICE EFFECTS...AND SOME
ERRONEOUS DATA MAY BE SEEN FROM TIME TO TIME.
A STORM SYSTEM WILL IMPACT THE REGION OVER THE WEEKEND WITH SOME
ADDITIONAL PRECIPITATION...MAINLY ON SUNDAY. IT IS STILL UNCLEAR
IN WHAT FORM THIS PRECIP WILL BE /RAIN...SNOW...OR MIXED
PRECIPITATION/ AND EXACT AMOUNTS ARE STILL FAR FROM CERTAIN. WE
WILL NEED TO MONITOR THE POTENTIAL FOR HOW THIS STORM MAY IMPACT
THE HYDROLOGIC AREA.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING
OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE
VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON
OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...FRUGIS
NEAR TERM...FRUGIS
SHORT TERM...FRUGIS
LONG TERM...NAS
AVIATION...NAS
HYDROLOGY...FRUGIS
AREA FORECAST DISCUSSION
NWS ALBANY NY
434 AM EST WED FEB 18 2015
.SYNOPSIS...
CLOUDS WILL INCREASE THROUGH THE DAY AHEAD OF AN
APPROACHING ARCTIC COLD FRONT. THIS FRONT WILL BRING SOME SNOW
SHOWERS AND SNOW SQUALLS TO THE REGION THIS EVENING INTO TONIGHT.
BITTER COLD TEMPERATURES...ALONG WITH A FEW ADDITIONAL SNOW
SHOWERS...WILL BE IN PLACE ACROSS THE REGION FOR THURSDAY INTO
FRIDAY. ANOTHER STORM SYSTEM WILL IMPACT THE AREA OVER THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 434 AM EST...A STRONG SHORTWAVE AND ASSOCIATED SFC COLD
FRONT IS SITUATED UPSTREAM OF THE REGION OVER THE GREAT LAKES.
SOME MID AND HIGH LEVEL CLOUDS HAVE STARTED TO MOVE INTO OUR
AREA...BUT THE MAJORITY OF THESE CLOUDS HAVE BEEN RATHER THIN.
WITH A DEEP SNOWPACK AND LIGHT WINDS IN PLACE...TEMPS HAVE BEEN
VERY COLD SO FAR THIS MORNING...WITH MOST AREAS BELOW ZERO...AND
SOME SPOTS IN THE ADIRONDACKS CLOSE TO -20 DEGREES F.
CLOUDS WILL CONTINUE TO LOWER AND THICKEN THROUGHOUT THE DAY AS
THE ARCTIC FRONT CONTINUES TO MOVE EASTWARD TOWARDS THE AREA. MOST
AREAS LOOK TO BE MOSTLY CLOUDY BY AFTERNOON. IT SHOULD STAY DRY
ACROSS THE REGION THROUGH THE EARLY EVENING...AS THE LATEST 07Z
3KM HRRR SHOWS A BAND OF SNOW SHOWERS STILL BACK OVER CNY NEAR THE
SYRACUSE AREA BY 5 PM. WILL START TO RAISE POPS FOR WESTERN AREAS
FOR THE LATE AFTN/EARLY EVENING IN CASE THIS SPEEDS UP...BUT MOST
AREAS WON/T SEE ANY SNOW UNTIL TONIGHT.
HIGH TEMPS TODAY WILL BE A LITTLE WARMER THAN TUESDAY...BUT STILL
BELOW NORMAL...WITH TEMPS RANGING FROM THE MID TEENS IN THE
ADIRONDACKS TO THE MID 20S IN THE HUDSON VALLEY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
THE ARCTIC COLD FRONT WILL BE PASSING FROM WEST TO EAST ACROSS THE
REGION TONIGHT. THE FRONT WILL BE SLOWED IN ITS PROGRESS...AS A
WEAK WAVE OF LOW PRESSURE DEVELOPS ALONG THE COLD/OCCLUDED
BOUNDARY. THE 00Z WFO BTV 4KM WRF SHOWS AN AREA OF SNOW SHOWERS
AND EMBEDDED SQUALLS IMPACTING THE REGION FROM WEST TO EAST DURING
THE OVERNIGHT HOURS. THE 00Z/06Z NAM ALSO SUGGESTS THIS WILL
OCCUR...ALTHOUGH THERE ARE SOME SLIGHT DIFFERENCES IN THE TIMING
DUE TO THE SLOW NATURE OF THE FRONTAL BOUNDARY. HAVE RAISED POPS
TO LIKELY FOR A FEW HOURS IN MOST LOCATIONS...WITH A LIGHT
ACCUMULATION OF 1-3 INCHES EXPECTED TONIGHT INTO THURSDAY
MORNING...WITH THE HIGHEST AMOUNTS FOR THE HIGHER ELEVATIONS. ALTHOUGH
QPF AMOUNTS ARE LIGHT...RATIOS ARE EXPECTED TO BE RATHER HIGH...AS
THE NAM BUFKIT SOUNDING SHOWS GOOD LIFT /OMEGA/ THROUGH THE
OPTIMAL DENDRITIC SNOW GROWTH LAYER. TEMPS LOOK TO COOL OFF
QUICKLY BEHIND THE BOUNDARY...WITH MINS LOWEST FOR WESTERN AREAS
/ZERO TO 5/ AND HIGHEST FOR EASTERN/SOUTHERN AREAS /GENERALLY 10
TO 15/.
WIDESPREAD SNOW SHOWERS WILL BE ONGOING THURSDAY MORNING...BUT
WILL BE TAPERING OFF BY MIDDAY FOR MOST AREAS...AS THE FRONT
CONTINUES TO PUSH EASTWARD...AND THE WAVE ON THE BOUNDARY RE-
DEVELOPS AND RAPIDLY STRENGTHENS OFF THE EASTERN NEW ENGLAND
COAST. TEMPS WON/T RISE TOO MUCH ON THURSDAY WITH THE STRONG COLD
AIR ADVECTION IN PLACE...AS 850 HPA TEMPS FALL TO -20 TO -25
DEGREES C. HIGHS WILL ONLY REACH THE SINGLE DIGITS TO MID TEENS.
SOME ADDITIONAL UPSLOPE SNOW MAY OCCUR WITH IN THE NW FLOW FOR
THE HIGH TERRAIN AREAS OF WESTERN NEW ENGLAND...AND SOME LAKE
ENHANCED SNOW SHOWERS COULD ALSO BE OCCURRING INTO THE MOHAWK
VALLEY/SCHOHARIE COUNTY THANKS TO THE FLOW MOVING ACROSS LAKE
ONTARIO. SOME ADDITIONAL ACCUMULATION OF AN INCH OR TWO IS
POSSIBLE FOR THESE AREAS.
WINDS WILL BE STARTING TO PICK UP BY THURSDAY AFTERNOON THANKS TO
THE INCREASING PRESSURE GRADIENT...AND WILL BE GUSTING 20-30 MPH
AT TIMES. THIS LOOK TO CONTINUE INTO THURSDAY NIGHT AS WELL...AND
TEMPS WILL BE FALLING TO ZERO TO -15 DEGREES F FOR LOW TEMPS FOR
THURSDAY NIGHT. WITH THE STRONG WINDS AND COLD TEMPS...WIND CHILLS
WILL CERTAINLY BE AN ISSUE. ADVISORY LEVEL WIND CHILLS APPEAR
LIKELY FOR MOST AREAS...AND A FEW SPOTS IN THE
ADIRONDACKS/CATSKILLS COULD POTENTIALLY REACH WARNING LEVELS AS
WELL. WILL CONTINUE TO HIGHLIGHT THESE THREATS IN THE HWO
STATEMENT. OUTSIDE OF THE BRUTALLY COLD TEMPS...SOME LINGERING
HIGH TERRAIN SNOW SHOWERS/FLURRIES ARE POSSIBLE...ALTHOUGH NOT
MUCH ADDITIONAL ACCUMULATION IS EXPECTED.
BITTER COLD TEMPS AND LOW WIND CHILL WILL REMAIN IN PLACE FOR
FRIDAY...ALTHOUGH WINDS WILL START TO REDUCE BY LATER IN THE DAY.
OUTSIDE A FEW FLURRIES/SNOW SHOWERS FOR THE WESTERN
ADIRONDACKS...NO PRECIP IS EXPECTED. MAX TEMPS WILL ONLY REACH THE
SINGLE DIGITS TO LOW TEENS...WITH A FEW SPOTS IN THE HIGH TERRAIN
REMAINING BELOW ZERO.
ANOTHER BITTER COLD NIGHT IS EXPECTED FOR FRIDAY NIGHT...BUT WIND
CHILLS WON/T BE AN ADDITIONAL CONCERN THANKS TO A LIGHT TO CALM
WINDS. STILL...TEMPS WILL BE VERY COLD...WITH MOST AREAS BELOW
ZERO ONCE AGAIN...AND SOME HIGH TERRAIN LOCATIONS -10 TO -20
DEGREES F. IT SHOULD REMAIN DRY...WITH A PARTLY TO MOSTLY CLEAR
SKY...AS HIGH PRESSURE SLIDES BY TO THE SOUTH OF THE AREA.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
APPROACHING UPPER ENERGY WILL RESULT IN THICKENING CLOUDS AND SLOWLY
INCREASING COVERAGE OF LIGHT SNOW. WARM ADVECTION WILL INCREASE...
AS WILL ISENTROPIC LIFT. SO HIGHS SATURDAY IN THE UPPER TEENS TO MID
20S...WITH JUST CHANCES FOR LIGHT SNOW IN THE AFTERNOON.
COVERAGE OF PRECIPITATION WILL INCREASE SATURDAY NIGHT INTO
SUNDAY...AS WILL WARM ADVECTION AND ISENTROPIC LIFT. LOW LEVEL JET
ENERGY WILL SPREAD NORTH AND EAST...ENHANCING THE WARM ADVECTION...
ESPECIALLY SUNDAY. THERE ARE SOME CONFLICTS COMPARING DETERMINISTIC
GUIDANCE AND ENSEMBLE GUIDANCE. DETERMINISTIC GUIDANCE SUGGESTS A
PRECIPITATION TRANSITION TO MIXED PRECIPITATION OR COLD RAIN FOR THE
MUCH OF THE FORECAST AREA SUNDAY...WHILE ENSEMBLE MEAN THERMAL
PROFILES SUGGEST THE DETERMINISTIC GUIDANCE IS ON THE WARMER SIDE OF
THE ENSEMBLE RANGE.
THE MEAN EASTERN NORTH AMERICAN UPPER TROUGH WILL HAVE TO RETROGRADE
QUITE A BIT FOR ENOUGH WARM AIR TO FLOOD THE EASTERN U.S. TO BRING
RAIN DURING AN OTHERWISE SNOWY AND COLD WINTER. THERE IS STILL LOTS
OF TIME TO WATCH THE DEVELOPMENT OF THIS SYSTEM...AND UNTIL THERE
ARE CLEAR SIGNALS FOR MIXED PRECIPITATION OR COLD RAIN...WILL
INDICATE SNOW IN MOST AREAS THROUGH SUNDAY...WITH THE EXCEPTION OF
PARTS OF THE EASTERN CATSKILLS...MID HUDSON VALLEY AND NW CT...WHERE
RAIN AND SNOW WILL BE INDICATED. HIGHS SUNDAY AROUND 30 TO THE MID
30S...MID TO UPPER 20S NORTHERN AREAS.
ONCE THE SYSTEM EXITS SUNDAY NIGHT...ANOTHER PUSH OF VERY COLD AIR
SPILLS INTO THE REGION...WITH MUCH BELOW NORMAL TEMPERATURES. HIGHS
MONDAY IN THE TEENS TO LOWER 20S...SOME UPPER SINGLE NUMBERS IN THE
SOUTHERN ADIRONDACKS. HIGHS TUESDAY IN THE MID TEENS TO LOWER 20S.
&&
.AVIATION /09Z WEDNESDAY THROUGH SUNDAY/...
RIDGING AT THE SURFACE WILL WEAKEN OVERNIGHT AS A LOW PRESSURE
SYSTEM APPROACHES FROM THE GREAT LAKES REGION. CIRRUS CLOUDS WILL
STREAM IN THROUGH THE EARLY MORNING OURS ALONG WITH SOME MID LEVEL
CLOUDS AHEAD OF THE APPROACHING SYSTEM. OVERALL CLOUDS WILL THICKEN
AND LOWER TODAY AS THE SYSTEM MOVES INTO THE REGION BRINGING CHANCE
OF SNOW SHOWERS TO THE AREA...MAINLY FOR AFTER 00Z/THU. KEEPING VFR
CONDITIONS WITH VCSH UNTIL COVERAGE OF SNOW SHOWERS CAN BE
DETERMINED...THEY MAY STAY JUST SCATTERED. INDICATING SCATTERED
CLOUDS AT AROUND 1500 FEET AFTER 00Z WITH THE POSSIBILITY OF A
CEILING DEVELOPING AT THAT LEVEL IF THE COVERAGE OF SNOW SHOWERS IS
GREATER THAN SCATTERED. WINDS CALM TO LIGHT AND VARIABLE THROUGH THE
PERIOD.
OUTLOOK...
WED NIGHT-THU: MODERATE OPERATIONAL IMPACT. CHC -SHSN.
THU NIGHT-FRI NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
SAT-SUN: MODERATE OPERATIONAL IMPACT. CHC SN.
&&
.HYDROLOGY...
ICE WILL CONTINUE TO THICKEN ON AREA RIVERS...STREAMS...LAKES...AND
PONDS...AS CONTINUED BELOW NORMAL TEMPERATURES REMAIN IN PLACE
THROUGH THE REMAINDER OF THE WEEK. TEMPERATURES LOOK TO STAY BELOW
FREEZING THROUGH SATURDAY.
ANY PRECIP...ALL IN THE FORM OF SNOW...WILL BE FAIRLY LIGHT OVER
THE NEXT FEW DAYS. SOME SNOW SHOWERS ARE POSSIBLE BETWEEN TODAY
AND TOMORROW...BUT THIS WILL HAVE LITTLE TO NO IMMEDIATE IMPACT ON
AREA WATERWAYS. SOME GAGES WILL EXPERIENCE ICE EFFECTS...AND SOME
ERRONEOUS DATA MAY BE SEEN FROM TIME TO TIME.
A STORM SYSTEM WILL IMPACT THE REGION OVER THE WEEKEND WITH SOME
ADDITIONAL PRECIPITATION...MAINLY ON SUNDAY. IT IS STILL UNCLEAR
IN WHAT FORM THIS PRECIP WILL BE /RAIN...SNOW...OR MIXED
PRECIPITATION/ AND EXACT AMOUNTS ARE STILL FAR FROM CERTAIN. WE
WILL NEED TO MONITOR THE POTENTIAL FOR HOW THIS STORM MAY IMPACT
THE HYDROLOGIC AREA.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING
OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE
VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON
OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...FRUGIS
NEAR TERM...FRUGIS
SHORT TERM...FRUGIS
LONG TERM...NAS
AVIATION...NAS
HYDROLOGY...FRUGIS
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
705 PM EST THU FEB 19 2015
.SYNOPSIS...
HIGH PRESSURE OVER THE OHIO VALLEY BUILDS INTO OUR REGION THROUGH
FRIDAY. LOW PRESSURE OVER THE LOWER MISSISSIPPI VALLEY ON SATURDAY
WILL MOVE INTO THE SAINT LAWRENCE VALLEY ON SUNDAY, LEADING TO A
STRONG COLD FRONTAL PASSAGE LATE SUNDAY. AN ARCTIC FRONTAL PASSAGE
WILL OCCUR LATE MONDAY, THEN LOW PRESSURE MAY DEVELOP JUST OFFSHORE
DURING THE TUESDAY AND WEDNESDAY TIME FRAME.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
A VERY COLD AIRMASS IS ENTRECHED ACROSS THE ENTIRE REGION. THIS WILL
RESULT IN DANGEROUSLY COLD WIND CHILLS ESPECIALLY OVERNIGHT AND EVEN
SOME RECORD LOWS POSSIBLE EARLY FRIDAY MORNING.
THE PRESENCE OF STEEP LOW-LEVEL LAPSE RATES WILL ASSIST IN MIXING
BEING MAINTAINED THROUGH THE NIGHT ACROSS MANY AREAS. THIS WILL ALSO
HELP TO GENERATE BANDS OF CLOUDS THAT MAY BE ENHANCED SOME BY A
STRONG SHORT WAVE ARRIVING OVERNIGHT. THE PRESENCE OF THE STEEP LOW-
LEVEL LAPSE RATES IS RESULTING IN SOME BANDS OF FLURRIES OR EVEN
SOME SNOW SHOWERS. SOME OF THE LIGHTER ACTIVITY MAY NOT REACH THE
GROUND GIVEN THE RATHER DRY SUB-CLOUD LAYER, HOWEVER SOME SNOW
SHOWERS HAVE BEEN OBSERVED IN A FEW PLACES SO FAR. THE HRRR SUGGESTS
THAT A FEW STREAMERS MAY SURVIVE FOR AWHILE TONIGHT. THEREFORE,
ADDED SCATTERED SNOW SHOWERS UP NORTH AND ISOLATED SNOW SHOWERS DOWN
SOUTH FOR AWHILE.
A WIND CHILL WARNING CONTINUES FOR THE POCONOS AND SUSSEX COUNTY
/NEW JERSEY/ WITH WIND CHILL VALUES OF 25-35 DEGREES BELOW ZERO. THE
REMAINDER OF THE CWA REMAINS UNDER A WIND CHILL ADVISORY WITH WIND
CHILL VALUES AS LOW AS 10-20 DEGREES BELOW ZERO.
THE HOURLY GRIDS WERE TWEAKED BASED ON THE LATEST OBSERVATIONS.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH 6 PM FRIDAY/...
ANOTHER HARSH BLAST OF ARCTIC AIR FOR THE REGION ON FRIDAY. MORNING
TEMPERATURES WILL START OFF IN THE SINGLE DIGITS OR BELOW ZERO IN
SOME CASES. WITH WINDS, WIND CHILL VALUES WILL BE WELL BELOW ZERO.
EVEN WITH A FULL DAYS ON SUNSHINE, MOST PLACES WILL STRUGGLE TO
REACH THE MID TEENS. WIND CHILL ADVISORIES (WARNINGS FOR THE POCONOS
AND SUSSEX NJ) CONTINUE UNTIL LATE MORNING FRIDAY. ONLY VERY MINOR
CHANGES TO THE PREVIOUS FORECAST. A MET/MAV BLEND RESULTED IN
TEMPERATURES ABOUT ONE DEGREE HIGHER THAN THE PREVIOUS FORECAST.
&&
.LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...
CLOSED MID-LEVEL LOW LIFTS OUT OF THE NORTHEAST US ON FRIDAY...AS
FLOW BECOMES MORE ZONAL AND SOUTHWESTERLY OVER THE E CONUS THROUGH
EARLY NEXT WEEK...BOUNDED BY A CLOSED LOW INVOF HUDSONS BAY AND AN
EVOLVING REX BLOCK ALONG THE WEST COAST OF NOAM. THE BEST CHANCE OF
PRECIP WILL BE IN ASSOCIATION WITH LOW PRESSURE MOVING JUST WEST OF
THE APPALACHIANS SATURDAY INTO SUNDAY...WITH PYTPE ISSUES
LIKELY... PARTICULARLY SATURDAY NIGHT. TEMPERATURES WILL MODERATE
THRU THE WEEKEND...THEN TURN MUCH COLDER AGAIN EARLY NEXT WEEK.
DAILIES...
FRIDAY NIGHT AND SATURDAY...HIGH PRESSURE WILL CREST OVER THE
REGION DURING THE PRE- DAWN HOURS WITH THE ATMOS DECOUPLING. AS
500 HPA FLOW BECOMES MORE SOUTHWEST...MID-LEVEL MOISTURE WILL BE
STREAMING IN FROM THE WEST. THUS THERE IS SOME UNCERTAINTY IN THE
TEMPERATURE FORECAST AS MORE CLOUD COVER WOULD PRECLUDE AN
OTHERWISE IDEAL RADIATIONAL COOLING SETUP. EXPECTING MINS AROUND
20 DEGREES BELOW NORMAL. DURING THE DAY...LOW PRESSURE APPROACHES
THE OHIO VALLEY...AS AS A LOW-LEVEL JET /60 KNOTS AT 850 HPA/
LEADS TO STRONG WARM AIR ADVECTION AND MOISTURE TRANSPORT WITH
GMEX ORIGINS. WITH SURFACE HIGH-PRESSURE POSITIONED JUST TO OUR
EAST OVER THE ATLANTIC...THERE WILL BE AN ABSENCE OF LOW-LEVEL DRY
AIR...SO THE COLUMN SATURATES QUICKLY.
MODELS ARE CONSISTENTLY TIMING THE ONSET OF PRECIP IN THE LATE AM TO
EARLY AFTERNOON HOURS. HOWEVER...GIVEN THE LACK OF MID-LEVEL RIDGING
AND DRY AIR AT THE SURFACE...WOULD NOT BE SURPRISED IF PRECIP BEGINS
A BIT EARLIER. THERMAL PROFILES SUPPORT PRECIP BEGINNING AS
SNOW... WITH A CHANGEOVER TO RAIN SOUTH AND EAST OF I-95 SATURDAY
EVENING. MODEL SOUNDINGS ALSO INDICATE AN ELEVATED WARM LAYER...SO
A BRIEF PERIOD OF SLEET IS POSSIBLE DURING THE CHANGEOVER FROM
SNOW TO RAIN. A PERIOD OF FREEZING RAIN IS ALSO POSSIBLE...ESP
INVOF THE DELAWARE VALLEY. THIS IS ALSO INDICATED BY THE CIPS
ANALOGS. ATTM... NOT EXPECTING SIGNIFICANT ICING. FURTHER
NORTHWEST OF I-95...WHERE SNOW MAY FALL WELL AFTER MIDNIGHT BEFORE
CHANGING OVER TO RAIN... ADVISORY LEVEL AMOUNTS ARE POSSIBLE.
SUNDAY...WITH THE SURFACE LOW TO THE WEST AND WAA CONTINUING...THE
ENTIRE COLUMN WILL WARM ABOVE FREEZING BY 12Z ACROSS THE CWA...SO
EXPECTING LIGHT RAIN. PRECIP WILL END BY THE AFTERNOON AS A STRONG
COLD FRONT MOVES THRU...WITH COLDER AND DRIER AIR FILTERING INTO THE
REGION. MAX TEMPS ARE FINALLY EXPECTED TO REACH SEASONABLE LEVELS.
MONDAY...A SECONDARY COLD FRONTAL PASSAGE DURING THE DAY WILL BRING
ARCTIC AIR BACK INTO THE REGION...WITH BRISK NORTHWEST WINDS AND
SNOW SHOWERS POSSIBLE IN THE POCONOS.
TUESDAY AND WEDNESDAY...EXPECTING TEMPERATURES ON TUESDAY 20 TO 25
DEGREES BELOW NORMAL WITH FAIR WEATHER. FOR WEDNESDAY...THE TROUGH
DIGS AGAIN IN THE EAST...WHICH MAY LEAD TO COASTAL CYCLOGENSIS
DURING THIS TIME FRAME.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
TONIGHT...VFR WITH A CEILING AT TIMES AROUND 5000 FEET. A FEW SNOW
SHOWERS AROUND, HOWEVER GIVEN LOW COVERAGE OVERALL A MENTION WAS NOT
INCLUDED. NORTHWESTERLY WINDS 10-15 KNOTS WITH GUSTS TO AROUND 25
KNOTS, ALTHOUGH THE GUSTS MAY DROP OFF FROM TIME TO TIME AT SOME
TERMINALS.
FRIDAY...VFR. NORTHWEST WINDS 10-15 KNOTS WITH GUSTS TO 25 KNOTS,
THEN DIMINISHING TO AROUND 10 KNOTS BY LATE AFTERNOON. AS THE WINDS
DIMINISH, A SHIFT TO A WEST OR EVEN SOUTHWEST DIRECTION SHOULD
OCCUR.
OUTLOOK...
FRIDAY NIGHT...VFR WITH SOME INCREASE IN CLOUDS LATE.
SATURDAY AND SATURDAY NIGHT: VFR CONDITIONS BECOMING MVFR/IFR SAT
AFTERNOON AND SAT NIGHT WITH SNOW CHANGING OVER TO RAIN. THERE MAY
ALSO BE A BRIEF PERIOD OF SLEET AND FREEZING RAIN...PARTICULARLY
AT ABE AND RDG.
SUNDAY: VFR AND IFR IN PERIODS OF RAIN...GRADUALLY IMPROVING TO
VFR FROM WEST TO EAST.
MONDAY AND TUESDAY...VFR CONDITIONS EXPECTED.
&&
.MARINE...
**SINCE MUCH OF DELAWARE BAY IS COVERED BY ICE WE WILL CONTINUE TO
ADD THE PHRASING "ON ICE FREE WATERS" FOR THE FIRST FOUR PERIODS
OF THE FORECAST**
NO CHANGES ON THE MID-AFTERNOON UPDATE. GALE WARNING CONTINUES
TONIGHT AND INTO FRIDAY ON THE ATLANTIC WATERS. AND FOR TONIGHT ON
THE DELAWARE BAY. COULD SEE WIND GUSTS TO 35 KNOTS ON THE
DELAWARE BAY AND UP TO 40 KNOTS ON THE ATLANTIC WATERS.
FREEZING SPRAY WARNING CONTINUES FOR TONIGHT INTO FRIDAY MORNING.
GUIDANCE CONTINUES TO SUPPORT THE THREAT FOR HEAVY FREEZING SPRAY.
CONDITIONS START TO IMPROVE LATER IN THE AFTERNOON FRIDAY AS WINDS
BEGIN TO DIMINISH.
OUTLOOK...
SATURDAY NIGHT THROUGH SUNDAY: SEAS BUILDING TO SCA THRESHOLDS
WITH WINDS APPROACHING SCA CRITERIA.
MONDAY AND TUESDAY...SEAS REMAINING AOA SCA LEVELS WITH WIND
GUSTS POSSIBLY REACHING GALE FORCE MONDAY NIGHT INTO EARLY
TUESDAY.
&&
.TIDES/COASTAL FLOODING...
A LOW WATER ADVISORY IS IN EFFECT FOR TONIGHT INTO FRIDAY OVER
THE DELAWARE BAY AND THE ATLANTIC COASTAL WATERS FOR THE NEXT TWO
UPCOMING LOW TIDES DUE TO BLOWOUT CONDITIONS FROM THE STRONG WEST-
NORTHWEST WINDS. LOW WATER ADVISORY IS CONTAINED IN THE MWW
PRODUCT. AN SPS WAS ISSUED FOR ASSOCIATED AREAS ALONG THE TIDAL
DELAWARE RIVER.
&&
.CLIMATE...
RECORD LOW TEMPERATURES ARE ANTICIPATED FRIDAY MORNING WHEN WE
NOW THINK THE COLDEST DAYS OF THE WINTER SHOULD OCCUR. THIS
BECAUSE MINUS 25C 850 MB AIR IS MORE MODELED TO OVERSPREAD MORE OF
OUR AREA AND SIT HERE FOR 12 HOURS. EVEN SATURDAY MAY HAVE RECORD
COLD NEAR MIDNIGHT BEFORE TEMPS START RISING AHEAD OF THE NEXT
ARCTIC COLD FRONT.
WE`RE TALKING THE COLDEST AT PHILADELPHIA SINCE JAN 19, 1994 WHEN
IT WAS 5 BELOW. IT WILL PROBABLY BE EASIER TO GET BELOW ZERO LATE
THIS WEEK DUE TO THE SOUTHWARD SNOW COVER INCREASE.
ADDITIONALLY FOR THE URBAN CENTERS AND THAT WILL FOCUS ON PHL...IF
THE LOW IS ZERO OR COLDER THIS WILL BE COLDEST LOW TEMPERATURE
AT PHL - SO LATE IN THE SEASON!
THOSE RECORDS LISTED BELOW...
(POR = PERIOD OF RECORD BEGINS)
POR 2/19 2/20 2/21
1874 KACY 4-1903 0-1966 3-1968
1872 KPHL 3-1903 1-1979 6-1968
1894 KILG 2-1936 5-1978 6 1968 AND 1934
1922 KABE 0-1936 -2 1936 0-1936
1865 KTTN 2 1903,1936 6 -1936 6-1893
1948 KGED 11-1993 0-1979 8-1959
1869 KRDG - 2 1903 -3 1903 -2 1978,1903
1901 KMPO -10 1903 -18 1993 -8 1993
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...WIND CHILL ADVISORY UNTIL 11 AM EST FRIDAY FOR PAZ060>062-070-
071-101>106.
WIND CHILL WARNING UNTIL 11 AM EST FRIDAY FOR PAZ054-055.
NJ...WIND CHILL ADVISORY UNTIL 11 AM EST FRIDAY FOR NJZ007>010-
012>027.
WIND CHILL WARNING UNTIL 11 AM EST FRIDAY FOR NJZ001.
DE...WIND CHILL ADVISORY UNTIL 11 AM EST FRIDAY FOR DEZ001>004.
MD...WIND CHILL ADVISORY UNTIL 11 AM EST FRIDAY FOR MDZ008-012-015-
019-020.
MARINE...HEAVY FREEZING SPRAY WARNING UNTIL 11 AM EST FRIDAY FOR ANZ430-
431-450>455.
LOW WATER ADVISORY UNTIL 6 PM EST FRIDAY FOR ANZ430-431-
450>455.
GALE WARNING UNTIL 1 PM EST FRIDAY FOR ANZ450>455.
GALE WARNING UNTIL 6 AM EST FRIDAY FOR ANZ430-431.
&&
$$
SYNOPSIS...FRANCK/GORSE
NEAR TERM...GORSE
SHORT TERM...SZATKOWSKI
LONG TERM...FRANCK
AVIATION...FRANCK/GORSE
MARINE...FRANCK/SZATKOWSKI
TIDES/COASTAL FLOODING...
CLIMATE...
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
ISSUED BY NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
956 AM EST WED FEB 18 2015
.SYNOPSIS...
LOW PRESSURE WILL TRACK THROUGH THE REGION ALONG A COLD FRONT THIS
EVENING. BY THURSDAY, HIGH PRESSURE WILL BEGIN TO DIVE SOUTHEAST
INTO THE CENTRAL UNITED STATES REACHING THE EAST COAST ON FRIDAY.
LOW PRESSURE WILL TRACK NORTHEAST FROM THE SOUTHERN PLAINS UP THE
APPALACHIANS THIS WEEKEND. ANOTHER AREA OF ARCTIC HIGH PRESSURE
WILL DIVE SOUTHEAST TOWARD THE REGION BY THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 14Z...SUNNY WITH ALL AREAS NOW ABOVE ZERO AND GENERALLY TEENS
TO LOW 20S. LIGHT NORTH FLOW WILL BECOME LIGHT SLY THIS AFTERNOON
AHEAD OF A COLD FRONT CURRENTLY OVER THE OHIO VALLEY. MAX TEMPS
MID 20S FOR ERN PA AND NRN NJ...LOW 30S FOR CNTRL/SRN NJ. LIGHT
FLOW/LACK OF MIXING MIGHT LIMIT TEMPS A BIT...BUT THE FULL
SUNSHINE WILL AT LEAST CAUSE MELTING OF THE SNOWPACK ACROSS THE
AREA (SEEN IN VISIBLE IMAGERY). WILL MANTAIN ABOVE AVG CONFIDENCE
FOR FCST TODAY.
SNOW SHOWERS OR FLURRIES WILL DEVELOP OVER EASTERN PA VERY LATE IN
THE DAY IN ASSOCIATION WITH LOW LEVEL CONVERGENCE AHEAD OF THE ARCTIC
COLD FRONT AND THE 500 MB PVA WITH THE APPROACHING 500MB TROUGH.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
BRIEF SNOW SHOWERS/WEAKENING SQUALL EXPECTED TO CROSS THE CWA THIS
EVENING. STILL ON TRACK FOR THE 1-2 INCHES IN FAR NWRN SECTIONS OF
THE CWA/POCONOS TO 0.5 TO 1 INCH ALONG THE DELAWARE RIVER/BAY TO
0.5 INCH ALONG THE SHORE.
WILL REISSUE/UPDATE SPS AT NOON.
PREVIOUS...
MODELS SUGGEST DECENT SNOW GROWTH WITH ANY OF THE MEASURABLE WATER
EQUIVALENT SNOW THAT SPREADS EWD THROUGH THE REGION. NAM MAY HAVE
A WET BIAS FOR TONIGHT BUT THERE IS LIKELY TO BE GENERAL DUSTINGS
TO SPOTTY 2-3 INCH SNOWS. 50 50 BLENDED 00Z/18 GFS/NAM MOS GUIDANCE
IS APPLIED EXCEPT I THOUGHT THE TEMPS WOULD RUN COLDER NEAR DAYBREAK
THURSDAY SO I BLENDED IN THE ECMWF 12Z THURSDAY TEMPS. LIGHT SOUTH
WIND BECOMES NW GUSTY 25 TO 30 MPH AFTER MIDNIGHT.
NO ADVY ATTM BUT AN SPS WAS ISSUED FOR EASTERN PA TO COVER THE
ONSET OF ACCUMULATIVE SLIPPERY TRAVEL SNOWS AND VERY RAPIDLY
CHANGING TRAVEL CONDITIONS. THE 10Z RAP AND 07Z HRRR HAVE IT TO
VARYING DEGREES.
CONFIDENCE: ABOVE AVERAGE.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
THURSDAY THROUGH FRIDAY NIGHT: THE ARCTIC FRONT WILL BE EAST OF THE
REGION WITH A FRESH SHOT OF COLD AIR COMING INTO THE REGION. LOW
TEMPERATURES FRIDAY MORNING LIKELY WILL BE AROUND 0 FOR MOST OF THE
REGION AIDED IN PART BY SNOWCOVER. DID GO A FEW DEGREES UNDER
MAV/MET TO ACCOUNT FOR THIS, THESE GUIDANCE SETS HAVE BEEN TO WARM
WITH LOW TEMPERATURES RECENTLY. WITH STRONG NORTHWEST WINDS BEHIND
THE FRONT, WIND CHILLS COULD BE AROUND -25 FRIDAY MORNING FOR THE
NORTHWEST PART OF THE CWA. A WIND CHILL WATCH HAS BEEN ISSUED FOR
THIS POSSIBILITY. WIND CHILLS WILL STILL BE DANGEROUSLY COLD ACROSS
THE ENTIRE REGION WITH PEAK VALUES FROM -15 TO -20. BE PREPARED TO
BUNDLE UP AND TAKE PLENTY OF PRECAUTIONS IF YOU HAVE TO BE OUT
LATE THURSDAY INTO FRIDAY. IN TERMS OF GUSTS, THE GFS IS A LITTLE
MORE ROBUST THAN THE NAM. THIS FORECAST TOOK A MIDDLE GROUND
APPROACH BETWEEN BUFKIT ANALYSIS FROM BOTH MODELS WHICH SHOW GUSTS
UP TO AND AROUND 30 MPH. STEEP LAPSE RATES MAY LEAD TO SOME PATCHY
FLURRIES ON THURSDAY.
SATURDAY AND SUNDAY: MODEL GUIDANCE HAS COME TO CONSENSUS THAT LOW
PRESSURE WILL FORM OVER THE SOUTHERN PLAINS AND HEAD NORTHEAST UP
THE APPALACHIANS BETWEEN TWO HIGH PRESSURE SYSTEMS. THE LACK OF A FIRM
HIGH PRESSURE SOURCE TO OUR NORTH MAKES THIS CUTTER TRACK POSSIBLE.
OVERRUNNING CLOUDS AND LIGHT PRECIPITATION IN ADVANCE OF A WARM FRONT WILL
MOVE NORTH SATURDAY WITH THE HIGHEST CHANCES OF PRECIPITATION FROM
LATE SATURDAY NIGHT THROUGH SUNDAY. A MIXTURE OF SNOW, ICE AND RAIN
IS LIKELY TO DEVELOP QUICKLY CHANGING TO RAIN ACROSS MOST OF THE
REGION, PERHAPS STAYING A MIX LONGER INTO SUNDAY ACROSS THE POCONOS.
PERIODS OF RAIN MAY THEN END AS SOME SNOW ON THE BACKEND, MOST
LIKELY FLURRIES BY SUNDAY NIGHT. A NON-DIURNAL TEMPERATURE TREND WAS
USED WITH THE CONSENSUS THAT TEMPERATURES RISE SATURDAY NIGHT FROM
AROUND 30 INTO THE 40`S ON SUNDAY. THE GFS IS WARMER THAN THE
CURRENT FORECAST BUT GIVEN A DECENT SNOWCOVER IN PLACE, STILL THINK
LOW LEVEL COLD AIR CAN PUT SOME FIGHT. SOME LIGHT ICE AND SNOW
ACCUMULATIONS ARE POSSIBLE WITH THE HIGHEST ACCUMULATIONS WELL NORTH
AND WEST OF OUR REGION. ALSO, DID TREND HIGHER THAN ENSEMBLE
GUIDANCE ON THE WINDS AS WELL.
MONDAY AND TUESDAY: ANOTHER COLD FRONT MOVES THROUGH MONDAY MORNING.
THIS COLD SHOT DOES NOT LOOK AS IMPRESSIVE AS THE PAST FEW BUT DID
TREND TEMPERATURES A FEW DEGREES COOLER THAN THE ENSEMBLE GUIDANCE.
FOR NOW, WILL JUST CARY A LINGERING CHANCE FOR SOME LIGHT SNOW ACROSS
THE REGION WITH THE ECMWF BEING SLOWER TO CLEAR THE FRONTAL BOUNDARY.
THERE IS POTENTIAL FOR ANOTHER WAVE OF LOW PRESSURE TO FORM ALONG
THE BOUNDARY TO OUR SOUTH AS SHOWN ON THE CMC MODEL AND TO SOME
EXTENT THE ECMWF BY THE END OF THE PERIOD. FOR NOW, WILL LEAVE OUT
OF FORECAST.
&&
.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
TODAY...VFR/SUNNY THIS MORNING. SCT CLOUDS AOA 15000 FT WITH SCT
CLOUDS NEAR 4000 FT MOVING IN FROM THE WEST THIS AFTN. THEN CIGS
NEAR 4000 FT ARRIVE LATE IN THE DAY OR EVENING. LIGHT WIND.
CONFIDENCE: ABOVE AVERAGE.
TONIGHT... VFR CIGS NEAR 4000 FT WITH BRIEF PERIODS OF IFR OR MVFR
CONDS IN SNOW SHOWERS FOR A 6 HOUR PERIOD MAINLY BETWEEN 00Z AND 06Z/19
BECOMING VFR SCT CLOUDS AOA 4000 FT TOWARD 09Z THURSDAY MORNING.
SNOWFALL FROM A DUSTING THAT COULD BE BLOWN OFF MOST PAVEMENTS BY
THE WEST NORTHWEST WIND GUSTS TO 25-30 KT THAT DEVELOPS AFTER
05Z/19, BUT SOME AMOUNTS RANGING UP TO 1-2 INCHES...POSSIBLY KRDG
TO KMPO. CONFIDENCE: AVERAGE.
OUTLOOK...
THURSDAY: VFR, NORTHWEST WIND GUSTS UP TO 30 KNOTS.
THURSDAY NIGHT THROUGH FRIDAY NIGHT: VFR.
SATURDAY AND SATURDAY NIGHT: CONDITIONS DETERIORATING TO MVFR/IFR
SATURDAY NIGHT WITH A MIX OF RAIN, SNOW AND FREEZING RAIN CHANGING
TO RAIN.
SUNDAY: VFR AND IFR IN RAIN.
&&
.MARINE...
**SINCE MUCH OF DELAWARE BAY IS COVERED BY ICE WE BEGIN ADDING
PHRASING "ON ICE FREE WATERS" FOR THE FIRST FOUR PERIODS OF THE
FORECAST**
TODAY...SCA HAZ SEAS FOR ALL THE ATLC WATERS UNTIL 5 PM EST. THIS
SWELL IS A RESULT OF YESTERDAYS STORM. FOR THE BAY SUB SCA
CONDITIONS CONTINUE TODAY IN A LIGHT WIND REGIME.
TONIGHT...GLW STARTS AT MIDNIGHT FOR DELAWARE BAY AND ANZ453-55.
REMAINING GALE FOR OTHER NNJ WATERS BEGINS 10 AM THURSDAY. THE
GALE IS A LOW ENDER .. MOSTLY 34-40 KT GUSTS.
OUTLOOK...
THURSDAY AND FRIDAY: NORTHWEST WIND GUSTS AROUND 35 KNOTS THROUGHOUT
MOST OF THIS PERIOD, DIMINISHING SOME FRIDAY AFTERNOON. FREEZING
SPRAY SOME MODERATE TO HEAVY IN ICE FREE AREAS. GALE WARNING.
LOW WATER AT LOW TIDES MAY BE A SERIOUS MARINE NAVIGATION HAZARD.
FRIDAY NIGHT AND SATURDAY: SUB SCA SEAS AND WINDS.
SATURDAY NIGHT AND SUNDAY: SEAS BUILDING TO SCA CRITERIA, SOUTHERLY
SCA GUSTS.
&&
.CLIMATE...
RECORD LOW TEMPERATURES ARE ANTICIPATED THIS THURSDAY AND OR FRIDAY
MORNING WHEN WE NOW THINK THE COLDEST DAYS OF THE WINTER SHOULD
OCCUR. THIS BECAUSE MINUS 25C 850 MB AIR IS MORE MODELED TO
OVERSPREAD MORE OF OUR AREA AND SIT HERE FOR 12 HOURS. EVEN
SATURDAY MAY HAVE RECORD COLD NEAR MIDNIGHT BEFORE TEMPS START
RISING AHEAD OF THE NEXT ARCTIC COLD FRONT.
WE`RE TALKING THE COLDEST AT PHILADELPHIA SINCE JAN 19, 1994 WHEN
IT WAS 5 BELOW. IT WILL PROBABLY BE EASIER TO GET BELOW ZERO LATE
THIS WEEK DUE TO THE SOUTHWARD SNOW COVER INCREASE.
ADDITIONALLY FOR THE URBAN CENTERS AND THAT WILL FOCUS ON PHL...IF
THE LOW IS ZERO OR COLDER THIS WILL BE COLDEST LOW TEMPERATURE
AT PHL - SO LATE IN THE SEASON!
THOSE RECORDS LISTED BELOW...
(POR = PERIOD OF RECORD BEGINS)
POR 2/19 2/20 2/21
1874 KACY 4-1903 0-1966 3-1968
1872 KPHL 3-1903 1-1979 6-1968
1894 KILG 2-1936 5-1978 6 1968 AND 1934
1922 KABE 0-1936 -2 1936 0-1936
1865 KTTN 2 1903,1936 6 -1936 6-1893
1948 KGED 11-1993 0-1979 8-1959
1869 KRDG - 2 1903 -3 1903 -2 1978,1903
1901 KMPO -10 1903 -18 1993 -8 1993
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...WIND CHILL WATCH FROM THURSDAY EVENING THROUGH FRIDAY MORNING
FOR PAZ054-055-060>062.
WIND CHILL ADVISORY FROM 4 AM TO 7 PM EST THURSDAY FOR PAZ054-
055.
NJ...WIND CHILL WATCH FROM THURSDAY EVENING THROUGH FRIDAY MORNING
FOR NJZ001-007.
DE...NONE.
MD...NONE.
MARINE...GALE WARNING FROM 10 AM THURSDAY TO 1 PM EST FRIDAY FOR
ANZ450>452.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 5 PM EST THIS
AFTERNOON FOR ANZ450>455.
GALE WARNING FROM MIDNIGHT TONIGHT TO 1 PM EST FRIDAY FOR
ANZ453>455.
GALE WARNING FROM MIDNIGHT TONIGHT TO 6 AM EST FRIDAY FOR
ANZ430-431.
&&
$$
UPDATE...JACKSON
PREVIOUS...DRAG/GAINES/658
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
658 AM EST WED FEB 18 2015
.SYNOPSIS...
LOW PRESSURE WILL TRACK THROUGH THE REGION ALONG A COLD FRONT TODAY.
BY THURSDAY, HIGH PRESSURE WILL BEGIN TO DIVE SOUTHEAST INTO THE CENTRAL
UNITED STATES REACHING THE EAST COAST ON FRIDAY. LOW PRESSURE WILL
TRACK NORTHEAST FROM THE SOUTHERN PLAINS UP THE APPALACHIANS THIS
WEEKEND. ANOTHER AREA OF ARCTIC HIGH PRESSURE WILL DIVE SOUTHEAST
TOWARD THE REGION BY THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
**THE STERLING OFFICE WILL BE BACKING US UP BEGINNING 8 AM TODAY AS WE
SHIFT FROM AWIPS 1 TO AWIPS2**
WE PRESUME WE WILL BE UP AND RUNNING SOMETIME LATE THIS EVENING.
TODAY...NICE AND SUNNY. STILL A LITTLE COLD BUT INCREASING SUN
ANGLE ALREADY MELTING SNOWS. LIGHT WIND THROUGH EARLY AFTERNOON.
50 50 BLENDED 00Z/18 GFS/NAM MOS GUIDANCE EXCEPT FCST THE WARMER
00Z/18 NAM MOS. MY CONCERN...LIGHT WIND AND LACK OF MIXING MIGHT
PREVENT REACHING THE FCST VALUES. FOR NOW THOUGH: ABOVE AVG
CONFIDENCE IN THIS PART OF THE FCST.
SNOW SHOWERS OR FLURRIES WILL DEVELOP OVER EASTERN PA VERY LATE IN
THE DAY IN ASSOCIATION WITH LOW LEVEL CONVERGENCE AHEAD OF THE ARCTIC
COLD FRONT AND THE 500 MB PVA WITH THE APPROACHING 500MB TROUGH.
06Z NAM AND GFS REVIEWED. NO CHANGE IN PHILOSOPHY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/...
MODELS SUGGEST DECENT SNOW GROWTH WITH ANY OF THE MEASURABLE WATER
EQUIVALENT SNOW THAT SPREADS EWD THROUGH THE REGION. NAM MAY HAVE
A WET BIAS FOR TONIGHT BUT THERE IS LIKELY TO BE GENERAL DUSTINGS
TO SPOTTY 2-3 INCH SNOWS. 50 50 BLENDED 00Z/18 GFS/NAM MOS GUIDANCE
IS APPLIED EXCEPT I THOUGHT THE TEMPS WOULD RUN COLDER NEAR DAYBREAK
THURSDAY SO I BLENDED IN THE ECMWF 12Z THURSDAY TEMPS. LIGHT SOUTH
WIND BECOMES NW GUSTY 25 TO 30 MPH AFTER MIDNIGHT.
NO ADVY ATTM BUT AN SPS WAS ISSUED FOR EASTERN PA TO COVER THE
ONSET OF ACCUMULATIVE SLIPPERY TRAVEL SNOWS AND VERY RAPIDLY
CHANGING TRAVEL CONDITIONS. THE 10Z RAP AND 07Z HRRR HAVE IT TO
VARYING DEGREES.
CONFIDENCE: ABOVE AVERAGE.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
THURSDAY THROUGH FRIDAY NIGHT: THE ARCTIC FRONT WILL BE EAST OF THE
REGION WITH A FRESH SHOT OF COLD AIR COMING INTO THE REGION. LOW
TEMPERATURES FRIDAY MORNING LIKELY WILL BE AROUND 0 FOR MOST OF THE
REGION AIDED IN PART BY SNOWCOVER. DID GO A FEW DEGREES UNDER
MAV/MET TO ACCOUNT FOR THIS, THESE GUIDANCE SETS HAVE BEEN TO WARM
WITH LOW TEMPERATURES RECENTLY. WITH STRONG NORTHWEST WINDS BEHIND
THE FRONT, WIND CHILLS COULD BE AROUND -25 FRIDAY MORNING FOR THE
NORTHWEST PART OF THE CWA. A WIND CHILL WATCH HAS BEEN ISSUED FOR
THIS POSSIBILITY. WIND CHILLS WILL STILL BE DANGEROUSLY COLD ACROSS
THE ENTIRE REGION WITH PEAK VALUES FROM -15 TO -20. BE PREPARED TO
BUNDLE UP AND TAKE PLENTY OF PRECAUTIONS IF YOU HAVE TO BE OUT
LATE THURSDAY INTO FRIDAY. IN TERMS OF GUSTS, THE GFS IS A LITTLE
MORE ROBUST THAN THE NAM. THIS FORECAST TOOK A MIDDLE GROUND
APPROACH BETWEEN BUFKIT ANALYSIS FROM BOTH MODELS WHICH SHOW GUSTS
UP TO AND AROUND 30 MPH. STEEP LAPSE RATES MAY LEAD TO SOME PATCHY
FLURRIES ON THURSDAY.
SATURDAY AND SUNDAY: MODEL GUIDANCE HAS COME TO CONSENSUS THAT LOW
PRESSURE WILL FORM OVER THE SOUTHERN PLAINS AND HEAD NORTHEAST UP
THE APPALACHIANS BETWEEN TWO HIGH PRESSURE SYSTEMS. THE LACK OF A FIRM
HIGH PRESSURE SOURCE TO OUR NORTH MAKES THIS CUTTER TRACK POSSIBLE.
OVERRUNNING CLOUDS AND LIGHT PRECIPITATION IN ADVANCE OF A WARM FRONT WILL
MOVE NORTH SATURDAY WITH THE HIGHEST CHANCES OF PRECIPITATION FROM
LATE SATURDAY NIGHT THROUGH SUNDAY. A MIXTURE OF SNOW, ICE AND RAIN
IS LIKELY TO DEVELOP QUICKLY CHANGING TO RAIN ACROSS MOST OF THE
REGION, PERHAPS STAYING A MIX LONGER INTO SUNDAY ACROSS THE POCONOS.
PERIODS OF RAIN MAY THEN END AS SOME SNOW ON THE BACKEND, MOST
LIKELY FLURRIES BY SUNDAY NIGHT. A NON-DIURNAL TEMPERATURE TREND WAS
USED WITH THE CONSENSUS THAT TEMPERATURES RISE SATURDAY NIGHT FROM
AROUND 30 INTO THE 40`S ON SUNDAY. THE GFS IS WARMER THAN THE
CURRENT FORECAST BUT GIVEN A DECENT SNOWCOVER IN PLACE, STILL THINK
LOW LEVEL COLD AIR CAN PUT SOME FIGHT. SOME LIGHT ICE AND SNOW
ACCUMULATIONS ARE POSSIBLE WITH THE HIGHEST ACCUMULATIONS WELL NORTH
AND WEST OF OUR REGION. ALSO, DID TREND HIGHER THAN ENSEMBLE
GUIDANCE ON THE WINDS AS WELL.
MONDAY AND TUESDAY: ANOTHER COLD FRONT MOVES THROUGH MONDAY MORNING.
THIS COLD SHOT DOES NOT LOOK AS IMPRESSIVE AS THE PAST FEW BUT DID
TREND TEMPERATURES A FEW DEGREES COOLER THAN THE ENSEMBLE GUIDANCE.
FOR NOW, WILL JUST CARY A LINGERING CHANCE FOR SOME LIGHT SNOW ACROSS
THE REGION WITH THE ECMWF BEING SLOWER TO CLEAR THE FRONTAL BOUNDARY.
THERE IS POTENTIAL FOR ANOTHER WAVE OF LOW PRESSURE TO FORM ALONG
THE BOUNDARY TO OUR SOUTH AS SHOWN ON THE CMC MODEL AND TO SOME
EXTENT THE ECMWF BY THE END OF THE PERIOD. FOR NOW, WILL LEAVE OUT
OF FORECAST.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
TODAY...VFR SCT CLOUDS AOA 15000 FT WITH SCT CLOUDS NEAR 4000 FT
DEVELOPING MIDDAY OR AFTN. THEN CIGS NEAR 4000 FT ARRIVE LATE IN
THE DAY OR EVENING. LIGHT WIND. CONFIDENCE: ABOVE AVERAGE.
TONIGHT... VFR CIGS NEAR 4000 FT WITH BRIEF PERIODS OF IFR OR MVFR
CONDS IN SNOW SHOWERS FOR A 6 HOUR PERIOD MAINLY BETWEEN 00Z AND 06Z/19
BECOMING VFR SCT CLOUDS AOA 4000 FT TOWARD 09Z THURSDAY MORNING.
SNOWFALL FROM A DUSTING THAT COULD BE BLOWN OFF MOST PAVEMENTS BY
THE WEST NORTHWEST WIND GUSTS TO 25-30 KT THAT DEVELOPS AFTER
05Z/19, BUT SOME AMOUNTS RANGING UP TO 1-2 INCHES...POSSIBLY KRDG
TO KMPO. CONFIDENCE: AVERAGE.
OUTLOOK...
THURSDAY: VFR, NORTHWEST WIND GUSTS UP TO 30 KNOTS.
THURSDAY NIGHT THROUGH FRIDAY NIGHT: VFR.
SATURDAY AND SATURDAY NIGHT: CONDITIONS DETERIORATING TO MVFR/IFR
SATURDAY NIGHT WITH A MIX OF RAIN, SNOW AND FREEZING RAIN CHANGING
TO RAIN.
SUNDAY: VFR AND IFR IN RAIN.
&&
.MARINE...
**SINCE MUCH OF DELAWARE BAY IS COVERED BY ICE WE BEGIN ADDING
PHRASING "ON ICE FREE WATERS" FOR THE FIRST FOUR PERIODS OF THE
FORECAST**
THIS INFO BEING HAND EDITED WILL NOT TRANSFER TO THE AUTOMATED POINT
AND CLICK POINT DATA.
ALSO ADDED A PHRASE ABOUT THE ICE IN THE MWW AND THE SYNOPSIS.
TODAY...EXTENDED THE SCA HAZ SEAS FOR ALL THE ATLC WATERS THROUGH 5
PM EST. THIS SWELL IS A RESULT OF YESTERDAYS STORM. FOR THE BAY
SUB SCA CONDITIONS CONTINUE TODAY IN A LIGHT WIND REGIME.
TONIGHT...WE STARTED THE GLW AROUND 06Z FOR DELAWARE BAY AND ANZ453-55.
WE DELAYED THE REMAINING GALE WARNING CONVERSION FOR OTHER NNJ WATERS
UNTIL DAYLIGHT THURSDAY. THE GALE IS A LOW ENDER .. MOSTLY 34-40 KT
GUSTS.
OUTLOOK...
THURSDAY AND FRIDAY: NORTHWEST WIND GUSTS AROUND 35 KNOTS THROUGHOUT
MOST OF THIS PERIOD, DIMINISHING SOME FRIDAY AFTERNOON. FREEZING
SPRAY SOME MODERATE TO HEAVY IN ICE FREE AREAS. GALE WARNING.
LOW WATER AT LOW TIDES MAY BE A SERIOUS MARINE NAVIGATION HAZARD.
FRIDAY NIGHT AND SATURDAY: SUB SCA SEAS AND WINDS.
SATURDAY NIGHT AND SUNDAY: SEAS BUILDING TO SCA CRITERIA, SOUTHERLY
SCA GUSTS.
&&
.TIDES/COASTAL FLOODING...
LOW WATER ADVISORIES WILL PROBABLY BE NEEDED FOR LOW TIDE CYCLES
THURSDAY AND FRIDAY MORNING FOR THE ATLC COASTS AND EVENTUALLY
SPS`S FOR THE TIDAL DEL RIVER FOR ALL THURSDAY AND FRIDAY LOW
WATER TIDE CYCLES - DESPITE ANY ICE LIMITATIONS TO MARINE NAVIGATION.
&&
.CLIMATE...
RECORD LOW TEMPERATURES ARE ANTICIPATED THIS THURSDAY AND OR FRIDAY
MORNING WHEN WE NOW THINK THE COLDEST DAYS OF THE WINTER SHOULD
OCCUR. THIS BECAUSE MINUS 25C 850 MB AIR IS MORE MODELED TO
OVERSPREAD MORE OF OUR AREA AND SIT HERE FOR 12 HOURS. EVEN
SATURDAY MAY HAVE RECORD COLD NEAR MIDNIGHT BEFORE TEMPS START
RISING AHEAD OF THE NEXT ARCTIC COLD FRONT.
WE`RE TALKING THE COLDEST AT PHILADELPHIA SINCE JAN 19, 1994 WHEN
IT WAS 5 BELOW. IT WILL PROBABLY BE EASIER TO GET BELOW ZERO LATE
THIS WEEK DUE TO THE SOUTHWARD SNOW COVER INCREASE.
ADDITIONALLY FOR THE URBAN CENTERS AND THAT WILL FOCUS ON PHL...IF
THE LOW IS ZERO OR COLDER THIS WILL BE COLDEST LOW TEMPERATURE
AT PHL - SO LATE IN THE SEASON!
THOSE RECORDS LISTED BELOW...
(POR = PERIOD OF RECORD BEGINS)
POR 2/19 2/20 2/21
1874 KACY 4-1903 0-1966 3-1968
1872 KPHL 3-1903 1-1979 6-1968
1894 KILG 2-1936 5-1978 6 1968 AND 1934
1922 KABE 0-1936 -2 1936 0-1936
1865 KTTN 2 1903,1936 6 -1936 6-1893
1948 AGED 11-1993 0-1979 8-1959
1869 KRDG - 2 1903 -3 1903 -2 1978,1903
1901 KMPO -10 1903 -18 1993 -8 1993
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...WIND CHILL WATCH FROM THURSDAY EVENING THROUGH FRIDAY MORNING
FOR PAZ054-055-060>062.
WIND CHILL ADVISORY FROM 4 AM TO 7 PM EST THURSDAY FOR PAZ054-
055.
NJ...WIND CHILL WATCH FROM THURSDAY EVENING THROUGH FRIDAY MORNING
FOR NJZ001-007.
DE...NONE.
MD...NONE.
MARINE...GALE WARNING FROM 10 AM THURSDAY TO 1 PM EST FRIDAY FOR
ANZ450>452.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 5 PM EST THIS
AFTERNOON FOR ANZ450>455.
GALE WARNING FROM MIDNIGHT TONIGHT TO 1 PM EST FRIDAY FOR
ANZ453>455.
GALE WARNING FROM MIDNIGHT TONIGHT TO 6 AM EST FRIDAY FOR
ANZ430-431.
&&
$$
SYNOPSIS...GAINES
NEAR TERM...DRAG 658
SHORT TERM...DRAG
LONG TERM...GAINES
AVIATION...DRAG/GAINES 658
MARINE...DRAG/GAINES 658
TIDES/COASTAL FLOODING...658
CLIMATE...
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
922 PM EST THU FEB 19 2015
.DISCUSSION...
...RECORD LOW TEMPERATURES TONIGHT WITH A FREEZE MANY LOCATIONS...
CURRENTLY-TONIGHT...CANAVERAL PROFILERS SHOWING LOW LEVEL NORTHWEST
WINDS 10 TO 15 KNOTS. A SMALL PATCH OF CIRRUS WAS ALSO TRAVERSING
THE AREA. AS A RESULT THE SURFACE TEMPS HAVE BEEN RUNNING A FEW
DEGREES ABOVE MOS GUIDANCE. THIS IS ABOUT WHAT WE FIGURED AS THE
RADIATIONAL COOLING COMPONENT WOULD BE MUTED SOME SINCE LOW LEVEL
WINDS WOULD NOT ALLOW SURFACE WINDS TO CALM OUT...EXCEPT IN THE
NORMALLY COLDER LOW LYING SPOTS. HENCE OUR FORECAST LOWS HAVE BEEN
STAYING A LITTLE ABOVE MOS GUIDANCE.
THE LATEST RAP SHOWS BOUNDARY LAYER WINDS OVER 10 KNOTS THE REST OF
THE NIGHT...SO DO NOT EXPECT COOLING MUCH MORE THAN ABOUT A DEGREE
PER HOUR. THIS WOULD PUT MOST AREAS AT OR BELOW THE FREEZING MARK.
LOW LYING SPOTS NORTHWEST OF I-4 COULD STILL EXPERIENCE A HARD
FREEZE. A LITTLE MORE GRADIENT FLOW IS INDICATED ALONG THE COAST
SOUTH OF CANAVERAL...SO STILL EXPECT FREEZING CONDITIONS TO BE
CONFINED TO THE MAINLAND THERE.
DO NOT SEE MUCH NEED TO ALTER THE CURRENT FORECAST PACKAGE.
&&
.AVIATION... VFR. SKC EXCEPT FOR A LITTLE PATCH OF CIRRUS EXITING
OFF TO THE EAST BY MIDNIGHT.
&&
.MARINE...
TONIGHT/FRI...NORTH/SOUTH ORIENTED HIGH PRESSURE RIDGE WILL SLIDE TO
THE EASTERN SEABOARD AND CAUSE NORTHWEST WINDS TO GRADUALLY VEER TO
THE NORTH LATE TONIGHT AND NORTH/NORTHEAST FRI AFTERNOON. THE
LATEST RAP MODEL SHOWS GRADIENT STAYING TIGHT ENOUGH TO SUPPORT 15-20
KNOTS OVER THE WATERS. THIS IS ENOUGH TO KEEP SEAS AROUND 7 FEET IN
THE GULF STREAM AND WARRANT SMALL CRAFT ADVISORY INTO EARLY FRI
MORNING. WINDS SHOULD GRADUALLY EASE THROUGH THE MORNING BUT WOULD
EXPECT AT LEAST AN EXERCISE CAUTION STATEMENT FOR MUCH OF FRI IN THE
GULF STREAM.
PREVIOUS WEEKEND DISCUSSION...
SURFACE HIGH CENTER MOVES OFF THE CAROLINA COAST AND INTO THE
ATLANTIC OVER THE WEEKEND...VEERING WINDS TO THE EAST-SOUTHEAST ON
SAT AND SOUTH-SOUTHEAST INTO SUN. GRADIENT WILL SUPPORT ANOTHER
ROUND OF ADVISORY CONDITIONS ON SAT WITH WINDS 20-25KTS SOUTH OF THE
CAPE AND 15-20KTS AREAS NORTH...BUILDING SEAS TO 7-8FT. WINDS WILL
DIMINISH INTO SUNDAY WITH SPEEDS 5-10KTS.
&&
.CLIMATE...
DAYTONA BEACH HAD A RECORD COOL HIGH TEMPERATURE TODAY OF 50 DEGREES.
PREVIOUSLY THE RECORD WAS 53 SET IN 1972. THE OTHER THREE CLIMATE SITES
WERE 1-2 DEGREES WARMER THAN THEIR COOLEST HIGH TEMPERATURE ON RECORD.
HERE ARE THE RECORD LOW TEMPERATURES FOR FRI FEB 20TH:
RECORD.....FORECAST
DAYTONA BEACH INT`L..29 (1958) 27
ORLANDO INT`L........33 (1958) 30
MELBOURNE INT`L......35 (1958) 31
VERO BEACH MUNI......35 (1958) 32
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...FREEZE WARNING FROM MIDNIGHT TONIGHT TO 9 AM EST FRIDAY FOR
INDIAN RIVER-MARTIN-NORTHERN BREVARD COUNTY-OKEECHOBEE-
ORANGE-OSCEOLA-SEMINOLE-SOUTHERN BREVARD COUNTY-ST. LUCIE.
WIND CHILL ADVISORY FROM 9 PM THIS EVENING TO 9 AM EST FRIDAY
FOR INDIAN RIVER-MARTIN-NORTHERN BREVARD COUNTY-SOUTHERN
BREVARD COUNTY-ST. LUCIE.
HARD FREEZE WARNING FROM MIDNIGHT TONIGHT TO 9 AM EST FRIDAY FOR
COASTAL VOLUSIA COUNTY-INLAND VOLUSIA COUNTY-NORTHERN LAKE
COUNTY-SOUTHERN LAKE COUNTY.
AM...SMALL CRAFT ADVISORY UNTIL 7 AM EST FRIDAY FOR FLAGLER BEACH
TO VOLUSIA-BREVARD COUNTY LINE 20-60 NM-SEBASTIAN INLET TO
JUPITER INLET 0-20 NM-SEBASTIAN INLET TO JUPITER INLET 20-60
NM-VOLUSIA-BREVARD COUNTY LINE TO SEBASTIAN INLET 20-60 NM.
&&
$$
SHORT TERM/AVIATION...LASCODY
IMPACT WX...BRAGAW
AREA FORECAST DISCUSSION
NWS MIAMI FL
430 AM EST WED FEB 18 2015
...COLD BLAST TO IMPACT SOUTH FLORIDA THROUGH FRI MORNING...
HIGHLIGHTS...
* WIND CHILL ADVISORY ISSUED FOR AREAS NORTH OF AN EVERGLADES CITY
TO BOCA LINE LATE TONIGHT-THU MORNING
* FREEZE WATCH ISSUED FOR GLADES, HENDRY, INTERIOR COLLIER
COUNTIES LATE THU NIGHT-FRI MORNING
* HIGH RISK OF RIP CURRENTS GULF BEACHES THROUGH THURSDAY
* SMALL CRAFT ADVISORY ALL LOCAL GULF AND ATLANTIC WATERS
.DISCUSSION...
A COLD FRONT WILL EXIT THE SOUTHERN TIP OF THE PENINSULA THIS
MORNING, USHERING IN A COLD AND DRY AIRMASS. TEMPS ARE ALREADY
BELOW FREEZING ACROSS THE WESTERN FLORIDA PANHANDLE. SO COLD AIR
ADVECTION WILL BE IN FULL FORCE TODAY WITH A LESS THAN 10F DEGREE
DIURNAL. THIS HOLDS HIGHS IN THE 60S MOST AREAS...EXCEPT AROUND
70F SOUTHEAST.
ANOTHER COLD FRONT OF ARCTIC ORIGIN...NOW LOCATED FROM OKLAHOMA TO
THE OHIO VALLEY...WILL SWEEP ACROSS THE STATE TONIGHT INTO EARLY
THURSDAY. EXTREMELY DRY MODIFIED ARCTIC AIR WILL POUR DOWN THE
PENINSULA WITH DEWPOINTS FORECAST TO PLUMMET INTO THE 20S...AND
POSSIBLY EVEN THE TEENS...VERY RARE FOR SOUTH FL. THICKNESS
PROFILES AND H85 OFF BOTH THE GFS AND ECMWF SUGGEST COLD WEATHER
IMPACTS WITH A FREEZE POSSIBLE ON THE COLDEST NIGHT...THU NIGHT.
HAVE ISSUED A FREEZE WATCH FOR GLADES, HENDRY, AND INTERIOR
COLLIER COUNTIES LATE THU NIGHT-EARLY FRI MORNING. GUIDANCE
SUGGESTS TEMPS DROPPING TO NEAR FREEZING ACROSS THESE LOCALES WITH
MID-UPPER 30S ELSEWHERE EXCEPT LOWER 40S ALONG THE IMMEDIATE SE
FL COAST. THERE WAS SOME THOUGHT TO LOWER TEMPS A TAD COMPARED TO
GUIDANCE AS MOS CAN SOMETIMES BE TOO WARM WITH SHALLOW COLD
AIRMASSES. HOWEVER, GIVEN THE SURFACE HIGH POSITION WITH PERHAPS
ENOUGH WIND MIXING AND THE UNCERTAINTY IN NORTHEASTERLY WIND
MODERATION TOWARDS FRI MORNING...DECIDED TO STAY CLOSE TO
GFS/ECMWF NUMBERS.
ANOTHER FACTOR WILL BE WIND CHILLS BOTH TONIGHT AND THU NIGHT AS
A BREEZE LOOKS TO PREVAIL EACH NIGHT. WINDS WILL BE SLIGHTLY
HIGHER TONIGHT COMPARED TO THU NIGHT...BUT BOTH NIGHTS WILL SEE
LOW WIND CHILLS. A WIND CHILL ADVISORY FOR SOUTH FL IS ISSUED WHEN
WIND CHILLS ARE FORECAST TO FALL TO AT OR BELOW 35F DEGREES FOR 3+
HOURS...AND THIS IS FORECAST TO OCCUR LATE TONIGHT-EARLY THU
ACROSS PALM BEACH, INTERIOR RURAL BROWARD, COLLIER, GLADES AND
HENDRY COUNTIES. SO A WIND CHILL ADVISORY HAS BEEN ISSUED FOR
THESE AREAS. ANOTHER WIND CHILL ADVISORY WILL BE NEEDED FOR THU
NIGHT-FRI MORNING...AND LIKELY EXPANDED TO COVER MORE OF SOUTH
FL...BUT THIS WILL BE ISSUED TOMORROW.
AFTER A RECORD OR NEAR RECORD COLD MORNING FRIDAY (SEE CLIMATE
SECTION BELOW), TEMPERATURES WILL QUICKLY MODERATE BY THIS
UPCOMING WEEKEND AS THE HIGH SHIFTS INTO THE ATLANTIC WITH A
RETURN TO A SE WIND FLOW...SENDING TEMPS BACK INTO THE 70S BY
SATURDAY AND SOME 80-DEGREE READINGS EARLY NEXT WEEK. GFS/ECMWF
SHOW ANOTHER COLD FRONT OF VARYING STRENGTH BY NEXT TUE OR WED.
/GREGORIA
&&
.MARINE...
DETERIORATING CONDITIONS AS NW WINDS INCREASE BEHIND A COLD FRONT.
SEAS WILL RAPIDLY BUILD...ESPECIALLY ACROSS THE GULF STREAM AND
OFFSHORE GULF WATERS. A SMALL CRAFT ADVISORY HAS BEEN ISSUED FOR
ALL LOCAL GULF AND ATLANTIC WATERS EFFECTIVE THROUGH EARLY FRIDAY
MORNING.
&&
.AVIATION...
LATEST HRRR CONTINUES TO DEPICT ENHANCEMENT OF SHOWERS AND
THUNDERSTORMS CURRENTLY ACROSS THE GULF WATERS AND EXTREME
SOUTHERN FLORIDA TIP. THIS ACTIVITY SHOULD CONTINUE TO PUSH TO THE
NORTHEAST THROUGH THE MORNING AND AFFECT THE EAST COAST
SITES...PRIMARILY KFXE AND SOUTHWARD. LEFT OUT ANY MENTION OF
THUNDER FOR NOW AS IT LOOKS LIKE THUNDER SHOULD REMAIN ISOLATED.
WILL AMEND AS NECESSARY. FROPA SHOULD OCCUR AT KAPF AND KPBI OVER
THE NEXT FEW HOURS AND AROUND 10Z-12Z AT THE REMAINDER OF THE EAST
COAST SITES. GUSTY NORTHWESTERLY WINDS SHOULD THEN PREVAIL BEHIND
THE FRONT AT ALL SITES THROUGH THE AFTERNOON BEFORE SUBSIDING
SLIGHTLY AFTER 00Z. /CD
&&
.FIRE WEATHER...
RELATIVE HUMIDITIES WILL BE TAKING A DIVE TODAY AND ESPECIALLY ON
THURSDAY AS A MODIFIED ARCTIC AIRMASS SWEEPS DOWN THE PENINSULA.
THIS WILL SEND EXTREMELY LOW DEWPOINT AIR INTO SOUTH
FLORIDA...INTO THE TEENS AND 20S BY THU AFTERNOON. MIN RELATIVE
HUMIDITIES ARE FORECAST TO FALL INTO THE 30S THIS AFTERNOON AND
20S EVERYWHERE THU AFTERNOON. A BREEZE NW WIND WILL PREVAIL AS
WELL EACH DAY. HOWEVER, ERC VALUES WILL BE BORDERLINE AT BEST. AS
SUCH, HAVE NOT ISSUED A FIRE WEATHER WATCH DUE TO THE ERC
CONSTRAINT ON RED FLAG CONDITIONS. /GREGORIA
&&
.CLIMATE...
RECORD LOWS ARE POSSIBLE FRIDAY MORNING. HERE ARE THE RECORD LOWS
FOR FEB. 20TH:
WEST PALM BEACH 42F (1920 AND 1958)
FT. LAUDERDALE 40F (1958 AND 1960)
MIAMI 42F (1972)
NAPLES 39F (1960)
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 69 39 56 36 / 50 0 0 0
FORT LAUDERDALE 71 44 57 41 / 50 0 0 0
MIAMI 73 44 58 41 / 50 0 0 0
NAPLES 66 44 58 38 / 30 0 0 0
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...FREEZE WATCH FROM LATE THURSDAY NIGHT THROUGH FRIDAY MORNING FOR
FLZ063-066-070.
WIND CHILL ADVISORY FROM 2 AM TO 9 AM EST THURSDAY FOR FLZ063-
066>071-168.
HIGH RIP CURRENT RISK FROM 7 AM EST THIS MORNING THROUGH
THURSDAY AFTERNOON FOR FLZ069.
AM...SMALL CRAFT ADVISORY FROM 7 AM THIS MORNING TO 1 AM EST FRIDAY
FOR AMZ650-651-670-671.
GM...SMALL CRAFT ADVISORY FROM 7 AM THIS MORNING TO 1 AM EST FRIDAY
FOR GMZ656-657-676.
&&
$$
AREA FORECAST DISCUSSION
NWS MIAMI FL
106 AM EST WED FEB 18 2015
.AVIATION...
LATEST HRRR CONTINUES TO DEPICT ENHANCEMENT OF SHOWERS AND
THUNDERSTORMS CURRENTLY ACROSS THE GULF WATERS AND EXTREME
SOUTHERN FLORIDA TIP. THIS ACTIVITY SHOULD CONTINUE TO PUSH TO THE
NORTHEAST THROUGH THE MORNING AND AFFECT THE EAST COAST
SITES...PRIMARILY KFXE AND SOUTHWARD. LEFT OUT ANY MENTION OF
THUNDER FOR NOW AS IT LOOKS LIKE THUNDER SHOULD REMAIN ISOLATED.
WILL AMEND AS NECESSARY. FROPA SHOULD OCCUR AT KAPF AND KPBI OVER
THE NEXT FEW HOURS AND AROUND 10Z-12Z AT THE REMAINDER OF THE EAST
COAST SITES. GUSTY NORTHWESTERLY WINDS SHOULD THEN PREVAIL BEHIND
THE FRONT AT ALL SITES THROUGH THE AFTERNOON BEFORE SUBSIDING
SLIGHTLY AFTER 00Z.
&&
.PREV DISCUSSION... /ISSUED 948 PM EST TUE FEB 17 2015/
UPDATE...
THE 00Z SOUNDING INDICATED INCREASING INSTABILITY WITH 500 HPA
TEMPERATURES DECREASING AND THE STABILITY INDICES DECREASING
ALTHOUGH THE MID LEVEL LAPSE RATES HAVE NOT SIGNIFICANTLY
DECREASED. BUT THE OVERALL ENVIRONMENT IS STILL SUPPORTIVE OF
THUNDERSTORMS WITH A FEW STRONG GUSTS. CURRENTLY MOST OF THE
THUNDERSTORM ACTIVITY IS IN THE EASTERN GULF TO THE WEST OF THE
FLORIDA KEYS. THE EARLIER GUIDANCE INDICATED THE JET STREAM
DIPPING SOUTHWARD INTO THE FLORIDA PENINSULA TONIGHT WITH THE 00Z
SOUNDING INDICATING WINDS OVER 100 KNOTS ABOVE 200 MB AND WINDS
AROUND 60 KNOTS HAVE DESCENDED TO BELOW 500 MB.
A SMALL CRAFT ADVISORY IS IN EFFECT THROUGH 12Z WEDNESDAY MORNING
FOR THE OFF SHORE ATLANTIC WATERS TO THE EAST OF PALM BEACH
COUNTY WITH REGIONAL WIND OBSERVATIONS INDICATING WINDS IN THE 20
TO 25 KNOT RANGE ARE LIKELY OCCURRING IN THE OFF SHORE WATERS. A
SMALL CRAFT ADVISORY WILL LIKELY BE ISSUED ON WEDNESDAY FOR ALL
REGIONAL GULF AND ATLANTIC WATERS FOR WEDNESDAY WITH INCREASING
WINDS AND HAZARDOUS SEAS EXPECTED AFTER THE FRONTAL PASSAGE ON
WEDNESDAY.
60
PREV DISCUSSION... /ISSUED 509 PM EST TUE FEB 17 2015/
DISCUSSION...
A COLD FRONT CONTINUES TO MOVE INTO THE FLORIDA PENINSULA WITH
EXTENSIVE CLOUD COVER INTO SOUTH CENTRAL FLORIDA AND ADJACENT GULF
AND ATLANTIC WATERS ALTHOUGH LIGHTNING ACTIVITY HAS BEEN ONLY
ISOLATED AND THUS FAR MAINLY LIMITED TO THE EASTERN GULF.
FOR TONIGHT...THE COLD FRONT WILL CONTINUE TO MOVE SOUTH ACROSS
THE FLORIDA PENINSULA AND ADJACENT WATERS WITH CHANCES OF SHOWERS
INCREASING LATE THIS EVENING AND OVERNIGHT. THE MOST COVERAGE OF
SHOWERS IS EXPECTED AFTER MIDNIGHT. WHILE THUNDERSTORM ACTIVITY
HAS SO FAR BEEN LIMITED THIS AFTERNOON...THE POTENTIAL WILL
INCREASE TONIGHT AS THE GUIDANCE INDICATES THE JET STREAM WILL
PASS ACROSS THE FLORIDA PENINSULA TONIGHT INTO WEDNESDAY. FORECAST
SOUNDINGS INDICATE 250 HPA WINDS REACHING IN EXCESS OF 100 KNOTS
AROUND 06Z WEDNESDAY. THIS COMBINED WITH INCREASING INSTABILITYAND
MID-LEVEL TEMPERATURES DECREASING SHOULD RESULT IN SOME
THUNDERSTORM ACTIVITY. FORECAST SOUNDINGS ALSO INDICATE WINDS
INCREASING TO THE LOWER LEVELS OVER NIGHT. THEREFORE WITH ANY
THUNDERSTORM ACTIVITY THERE COULD BE GUSTY WINDS TO NEAR 50 MPH
POSSIBLE WITH A STRONGER THUNDERSTORM.
GUIDANCE CONSISTENTLY INDICATES THE FRONT CLEARING THE REGION
ON WEDNESDAY WITH HIGH PRESSURE...INCREASING WINDS AND SIGNIFICANT COLD
AIR ADVECTION DOWN THE FLORIDA PENINSULA AS THE DAY PROGRESSES.
IN ADDITION WEDNESDAY NIGHT INTO THURSDAY MORNING A SECONDARY DRY
COLD FRONT IS FORECAST TO PASS ACROSS THE FLORIDA PENINSULA WITH
COLD AIR OF ARCTIC ORIGIN COMING DOWN THE FLORIDA PENINSULA. THE
LATEST TEMPERATURE GUIDANCE HAS BEEN VERY CONSISTENT WITH THIS
SCENARIO AND HAS BEEN WELL ADVERTISED THE LAST COUPLE OF DAYS WITH
LITTLE CHANGE IN THE FORECAST. THE COLDEST TEMPERATURE AND WIND
CHILL IMPACTS ARE EXPECTED ON WEDNESDAY NIGHT INTO THURSDAY AND
THURSDAY NIGHT INTO FRIDAY. ON WEDNESDAY NIGHT INTO
THURSDAY...STRONG WINDS ARE FORECAST ACROSS THE REGIONAL WATERS
AND THE WINDS WILL NOT LIKELY COMPLETELY DE-COUPLE OVER LAND OVER
NIGHT AS USUAL. THUS WIND CHILLS COULD BE NEAR 30 IN THE NORTHERN
INTERIOR AND POSSIBLY NEAR THE MID 30`S IN THE INTERIOR PORTIONS
OF THE NAPLES AND ATLANTIC METRO AREAS. THURSDAY NIGHT INTO
FRIDAY...REGIONAL WINDS ARE FORECAST TO DECREASE BUT TEMPERATURES
ARE FORECAST TO LOWER TO NEAR FREEZING IN THE NORTHERN INTERIOR
WEST OF LAKE OKEECHOBEE AND COULD DROP TO NEAR 40 OR UPPER 30S IN
PORTIONS OF THE NAPLES AND ATLANTIC COAST METRO AREAS. A FREEZE
WATCH MAY BE NEED FOR PORTIONS OF THE INTERIOR FOR EARLY FRIDAY
MORNING. ANY WATCHES OR WARNINGS FOR WEDNESDAY NIGHT OR THURSDAY
NIGHT WILL BE CONSIDERED DURING THE NIGHT SHIFT TONIGHT.
MARINE...
WITH THE FRONTAL PASSAGE TONIGHT DISCUSSED AT LENGTH
ABOVE...WINDS AND SEAS WILL BUILD ACROSS THE REGIONAL WATERS
TONIGHT INTO WEDNESDAY MORNING WITH SMALL CRAFT ADVISORIES LIKELY
TO BE ISSUED FOR THE LOCAL GULF AND ATLANTIC WATERS FOR WEDNESDAY MORNING.
HAZARDOUS SEAS ARE FORECAST TO BUILD ACROSS THE GULF AND ATLANTIC
WATERS STARTING AROUND 12Z WEDNESDAY AND PERSISTING THROUGH
THURSDAY NIGHT WITH CONDITIONS SLOWLY IMPROVING THEREAFTER.
FIRE WEATHER...
A STRONG COLD FRONT WILL BE MOVING THROUGH SOUTH FLORIDA LATE
TONIGHT INTO EARLY WEDNESDAY MORNING. THIS FRONT WILL BRING IN MUCH
DRIER AIR TO SOUTH FLORIDA STARTING WEDNESDAY AFTERNOON THROUGH
FRIDAY. THE RELATIVE HUMIDITY ON WEDNESDAY AFTERNOON WILL BE FALLING
INTO THE MID TO UPPER 30S FOR A COUPLE OF HOURS. HOWEVER...THE
RELATIVE HUMIDITY ON THURSDAY WILL FALL INTO THE LOWER TO MID 20S.
THE 20 FOOT WINDS WILL ALSO BE AROUND 15 MPH WITH THE ERC IN THE MID
20S. THIS WILL PUT SOUTH FLORIDA CLOSE TO THE FIRE DANGER CONDITIONS
ON THURSDAY. THEREFORE...IF THE FORECAST TREND CONDITIONS IN LATER
MODEL GUIDANCE THEN FIRE WEATHER HEADLINES WILL MORE LIKELY BE
NEEDED FOR THURSDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 69 40 60 39 / 30 0 0 0
FORT LAUDERDALE 71 45 60 43 / 50 0 0 0
MIAMI 72 47 62 43 / 50 0 0 0
NAPLES 64 45 59 40 / 30 0 0 0
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...SMALL CRAFT ADVISORY UNTIL 7 AM EST THIS MORNING FOR AMZ670.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1147 AM CST WED FEB 18 2015
.SHORT TERM...
315 AM CST
THROUGH THURSDAY...
A MASSIVE UPPER LOW/TROUGH CENTERED OVER
NORTHERN ONTARIO CONTINUES TO BE SPREAD ACROSS MOST OF NORTH
AMERICA. AN EMBEDDED SHORTWAVE IS TRACKING SOUTHEAST ACROSS SOUTHERN
WISCONSIN/NORTHERN IOWA AND WILL CROSS THE LOCAL AREA THROUGH THE
MORNING. WATER VAPOR SHOWS SHARP RIDGING OVER THE WEST COAST
EXTENDING WELL INTO THE YUKON/NUNAVUT WITH A STRAIGHT NORTH/SOUTH
TRAJECTORY DOWN THE WEST FLANK OF THE BIG TROUGH INTO THE PLAINS.
EVENING UPPER AIR ANALYSIS SHOWS H85 TEMPS OF -28C INTO NORTHERN
MINNESOTA BEHIND THE APPROACHING SHORTWAVE AND ON TRACK TO WORK INTO
THE LOCAL AREA LATER TODAY. AT THE SURFACE...A BROAD AREA OF LOW
PRESSURE STRETCHES FROM WESTERN QUEBEC SOUTHWEST TO LAKE HURON WITH
A SECONDARY LOW CIRCULATION OVER LOWER MICHIGAN. A COLD FRONT
EXTENDS SOUTHWEST FROM THE CENTRAL WISCONSIN ACROSS IOWA AND WILL
CROSS THE AREA THIS MORNING. THE LARGER SCALE ASCENT AND THE INFLUX
OF COLD AIR IS DRIVING AREAS OF LIGHT SNOW WITH SOME EMBEDDED SNOW
SHOWERS. THIS ACTIVITY WILL WORK ACROSS THE AREA THROUGH MID
MORNING. OVERALL IT WILL REMAIN LIGHT BUT DO EXPECT MORE INTENSE
RETURNS TO BE EMBEDDED WITHIN THE BROADER AREA OF LIGHT
SNOW...ESPECIALLY AFTER DAYBREAK. A FEW TENTHS OF ACCUMULATION IS
POSSIBLE WITH THE MORE PERSISTENT SHOWERS WITH AROUND A HALF INCH
NOT OUT OF THE QUESTION GIVEN THAT THE SNOW WILL BE FLUFFY BUT MANY
AREAS MAY SEE LITTLE MORE THAN A DUSTING. CONTINUED COLD
ADVECTION/CYCLONIC FLOW WILL SUPPORT FLURRIES OR SOME LIGHT SNOW
THROUGH THE REST OF THE DAY ONCE THE MAIN WAVE HAS DEPARTED. LAKE
EFFECT SNOW SHOWERS WILL BE OCCURRING EAST OF LAKE MICHIGAN AND WILL
LIKELY PERIODICALLY AFFECT PORTIONS OF PORTER COUNTY. FAR NORTHEAST
SECTIONS ARE MOST FAVORED FOR LIGHT ACCUMULATION...POSSIBLY AROUND
AN INCH.
COLD ADVECTION WILL PERSIST THROUGH THE DAY. HIGH TEMPS WILL BE A
LITTLE TRICKY GIVEN THAT THERE WILL PROBABLY BE AT LEAST SOME BREAKS
OF SUNSHINE FROM LATE MORNING THROUGH THE AFTERNOON. THE CORE OF THE
COLDEST AIR DOES NOT ARRIVE UNTIL THIS EVENING SO THERE SHOULD BE AT
LEAST SOME MODEST RECOVERY FROM MORNING TEMPS BEFORE THEY LEVEL OFF
AND PROBABLY FALL SOMEWHAT DURING THE AFTERNOON. THIS WILL PUT HIGHS
IN THE SINGLE DIGITS FOR MOST AREAS THOUGH THE SOUTHEAST THIRD OF
THE AREA MAY SEE READINGS OF 10 OR JUST ABOVE. HIGH PRESSURE WILL BE
SPREADING INTO THE MISSISSIPPI RIVER VALLEY THROUGH TONIGHT KEEPING
THE LOCAL AREA IN THE PRESSURE GRADIENT BETWEEN IT AND LOW PRESSURE
TO THE EAST. THIS WILL KEEP A STEADY NORTHWEST BREEZE IN PLACE
KEEPING TEMPS FROM RADIATING OUT BUT LOWS WILL STILL BE BITTERLY
COLD IN THE -4 TO -10 OR SO RANGE. WIND CHILLS WILL BE PUSHED TO -20
TO -30 SO WILL ISSUE A WIND CHILL ADVISORY FROM THIS EVENING THROUGH
MUCH OF THURSDAY MORNING. THE BIG UPPER TROUGH WILL SHIFT EAST
THURSDAY ALLOWING FOR SOME WARMING OF THE MID LEVELS BY LATE DAY.
THE SURFACE HIGH WILL BE OVERHEAD BY AFTERNOON SO WEAK MIXING WILL
NOT BE ABLE TO TAKE ADVANTAGE OF THE WARMING ALOFT. THIS WILL LIKELY
KEEP HIGHS IN THE MID SINGLE DIGITS BUT THE WILD CARD WILL BE THE
SUN WHICH IS QUITE STRONG AND WITH AN OLD SNOW PACK MAY BE ABLE TO
PROVIDE AN EXTRA FEW DEGREES OVER FORECAST HIGHS. REGARDLESS IT WILL
BE COLD AND 3 OF THE 4 RECORD TEMPS OUTLINED BELOW WILL BE IN
JEOPARDY THURSDAY. WINDS WILL BE MUCH LIGHTER THURSDAY NIGHT
ALLOWING FOR BETTER RADIATIONAL COOLING BUT MID/HIGH CLOUDS WILL BE
APPROACHING FROM THE WEST WHICH COULD ALLOW FOR SOME WARMING LATE.
SOME NORTHERN AREAS MAY NEED A WIND CHILL ADVISORY WITH WIND CHILLS
IN THE LOWER MINUS 20S.
MDB
&&
.LONG TERM...
315 AM CST
FRIDAY THROUGH TUESDAY...
THE UPPER FLOW WILL BE FLATTENING FRIDAY AS
THE BIG TROUGH CONTINUES EAST AND A WEAK UPPER TROUGH WORKS
SOUTHEAST INTO THE NORTHERN PLAINS. WARM ADVECTION WILL CONTINUE
ALOFT AND WITH THE SURFACE HIGH SHIFTING EAST SOUTHERLY FLOW WILL
DEVELOP AT THE SURFACE LEADING TO A MODERATION OF TEMPS. THE WARM
ADVECTION IN ADVANCE OF THE UPPER TROUGH/CLIPPER WILL BRING
INCREASED CLOUD COVER AND MAYBE SOME LIGHT SNOW SO WILL CARRY LOW
POPS FRIDAY. THINGS BECOME MORE INTERESTING AND COMPLEX FRIDAY NIGHT
AND SATURDAY AS A LARGER SCALE TROUGH DIGS INTO THE DESERT
SOUTHWEST. THIS WILL TRIGGER SURFACE LOW DEVELOPMENT ACROSS TEXAS
WITH AN INVERTED TROUGH/WARM FRONT DEVELOPING TO THE NORTHEAST. THE
SFC LOW WILL LIFT NORTHEAST COMBINING WITH AN OPEN GULF TO BRING A
GOOD PUSH OF MOISTURE NORTHEAST WITH IT. THE SIGNAL FOR THIS SYSTEM
HAS BEEN IN PLACE FOR SEVERAL DAYS BUT TRACK/STRENGTH DETAILS HAVE
BEEN INCONSISTENT. TYPICALLY A FURTHER SOUTH TRACK WOULD BE FAVORED
COMING OUT OF SUCH A STRONG ARCTIC BLAST BUT WITH THE INITIAL
TROUGH/CLIPPER AND DE-AMPLIFICATION OF THE UPPER FLOW BEFORE THE
MAIN TROUGH DRIVING THIS SYSTEM COMES INTO PLAY THE MID LEVEL
THERMAL GRADIENT WILL BE ABLE TO BE PUSHED BACK TOWARD THE AREA. IT
SEEMS THAT GUIDANCE MAY CONTINUE TO FAVOR A NORTHWARD TREND...WHICH
HAS BEEN THE TREND WITH MOST OF THESE SOUTHERN SYSTEMS THIS WINTER.
THIS WILL BE SOMETHING TO WATCH AND FOR NOW SOUTHEAST AREAS WILL BE
AT GREATEST RISK TO HAVE PRECIP FALL SO WILL CONTINUE WITH HIGHEST
POPS IN THESE AREAS. TEMP DETAILS WILL ALSO DEPEND ON THE TRACK BUT
LOWER 30S LOOK GOOD FOR NOW...WITH PRECIP TYPE POSSIBLY BECOMING AN
ISSUE.
COLDER AIR WILL SPREAD IN BEHIND THIS SYSTEM AS CANADIAN HIGH
PRESSURE ONCE AGAIN MOVES INTO THE CENTRAL U.S. SEVERAL UPPER
TROUGHS/CLIPPERS LOOK TO CROSS THE REGION EARLY NEXT WEEK CARVING
OUT ANOTHER BIG UPPER TROUGH SO THE MILDER AIR OF FRIDAY/SATURDAY
WILL BE SHORT LIVED WITH COLDER THAN NORMAL ARCTIC AIR EXPECTED TO
TAKE OVER FOR MUCH OF NEXT WEEK. IN OTHER WORDS THE CONDITIONS OF
THE RECENT FEW DAYS LOOK TO BE REPEATED TEMP AND PRECIP WISE WITH
BOUTS OF LIGHT SNOW WITH EACH PASSING WAVE.
MDB
&&
.CLIMATE...
WHILE THE COLDEST AIR ALOFT ARRIVES WEDNESDAY...THE COLDEST SURFACE
TEMPERATURES MAY RESULT ON THURSDAY FEBRUARY 19TH...WHICH RIGHT NOW
APPEARS COULD JEOPARDIZE SOME RECORDS...ESPECIALLY THE RECORD LOW
MAXIMUM TEMPERATURES.
FEB 19TH
RECORD LOW RECORD LOW MAX
CHICAGO -7 (1936) 9 (1936)
ROCKFORD -16 (1979) 7 (1959)
MTF/RC
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* FLURRIES OR BRIEF LIGHT SNOW SHOWERS POSSIBLE THROUGH THIS
AFTERNOON.
* MVFR CEILINGS POSSIBLE EARLY THIS AFTERNOON.
* GUSTY NORTHWEST WINDS THROUGH THE AFTERNOON.
RODRIGUEZ
//DISCUSSION...UPDATED 18Z...
FLURRIES AND LIGHT SNOW SHOWERS CONTINUE ACROSS THE AREA EARLY
THIS AFTERNOON AND WILL LIKELY PERSIST THROUGH THE
AFTERNOON...PERIODICALLY MOVING OVER THE TERMINALS. IF THIS WERE
TO OCCUR...EXPECT ANY SNOW TO BE LIGHT AND BRIEF. CURRENT MVFR
CEILINGS IN PLACE SHOULD NOT LAST LONG THIS AFTERNOON...BUT BECOME
VFR. THESE CLOUDS WILL THEN DIMINISH AS WELL AS THE WINDS LATER
THIS EVENING...BUT WITH A STEADY NORTHWEST WIND CONTINUING TONIGHT
INTO THURSDAY MORNING.
RODRIGUEZ
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH CONFIDENCE WITH FLURRIES/SNOW SHOWERS.
* HIGH CONFIDENCE WITH MVFR CEILINGS AND DURATION.
* HIGH CONFIDENCE WITH WIND SPEED/DIRECTION.
RODRIGUEZ
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT...VFR. LIGHT AND VARIABLE WINDS.
FRIDAY...CHANCE OF SN WITH IFR POSSIBLE. MODERATELY STRONG SOUTH
WINDS.
SATURDAY...CHANCE OF MVFR/IFR AND SN.
SUNDAY...MVFR CIGS POSSIBLE. SLIGHT CHANCE OF -SN EARLY.
MONDAY...PRIMARILY VFR.
TUESDAY...SLIGHT CHANCE OF SNOW SHOWERS WITH MVFR TO IFR
POSSIBLE.
KJB
&&
.MARINE...
117 AM CST
A PERIOD OF STRONG NORTHWESTERLY WINDS IS STILL EXPECTED TO DEVELOP
ACROSS THE LAKE TODAY INTO TONIGHT. THE SURFACE PRESSURE GRADIENT
WILL TIGHTEN IN THE WAKE OF A SURFACE LOW...CURRENTLY SHIFTING
EASTWARD OVER THE UPPER GREAT LAKES REGION...AND AHEAD OF AN
ARCTIC SURFACE HIGH SHIFTING OVER THE NORTHERN PLAINS. IT APPEARS
THESE STRONG NORTHWEST WINDS WILL RANGE BETWEEN 30 KT AND SOME LOW
END 35 KT GALES...ESPECIALLY ACROSS THE SOUTHERN HALF OF LAKE
MICHIGAN. THE CURRENT HEADLINES FOR GALES AND FREEZING SPRAY
APPEAR TO BE ON TARGET...SO NO CHANGES ARE PLANNED AT THIS TIME.
HOWEVER...WE WILL NEED TO WATCH FOR THE POSSIBILITY OF A TIME
EXTENSION OF THE GALE/FREEZING SPRAY HEADLINE THROUGH THE NIGHT
TONIGHT...AS FORECAST GUIDANCE SUGGESTS THAT THE WINDS COULD
REMAIN ELEVATED THROUGH EARLY THURSDAY MORNING AS THE COLD ARCTIC
AIR MASS CONTINUES TO FILTER OVER THE LAKE.
WINDS WILL EASE FOR A PERIOD LATER THURSDAY AS THE SURFACE RIDGE OF
HIGH PRESSURE BEGINS TO SHIFT OVER THE WESTERN LAKES REGION.
HOWEVER...IT APPEARS THAT WINDS WILL QUICKLY PICK UP OUT OF THE
SOUTH BY FRIDAY AS ANOTHER CLIPPER SYSTEM TRACKS ACROSS SOUTHERN
CANADA. THIS LOOKS TO RESULT IN 30 KT SOUTHERLY WINDS AND MORE
FREEZING SPRAY LAKE-WIDE ON FRIDAY.
ANOTHER STORM SYSTEM LOOKS TO DEVELOP AND SHIFT SOUTH OF THE LAKE ON
SUNDAY. DEPENDING ON THE ACTUAL STRENGTHEN OF THIS SYSTEM...IT COULD
RESULT IN A PERIOD OF STRONG NORTHERLY WINDS DOWN THE LAKE.
HOWEVER...UNCERTAINTY IS STILL SOMEWHAT HIGH WITH THIS SYSTEM.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WIND CHILL ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-
ILZ023-ILZ032-ILZ033-ILZ039...6 PM WEDNESDAY TO NOON
THURSDAY.
IN...WIND CHILL ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019...6 PM
WEDNESDAY TO NOON THURSDAY.
LM...GALE WARNING...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-
LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 PM
WEDNESDAY.
HEAVY FREEZING SPRAY WARNING...LMZ080-LMZ567-LMZ669-LMZ671-
LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-
LMZ876-LMZ878 UNTIL 9 PM WEDNESDAY.
SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO BURNS HARBOR UNTIL
9 AM THURSDAY.
GALE WARNING...NEARSHORE BURNS HARBOR TO MICHIGAN CITY IN UNTIL 6 PM WEDNESDAY.
&&
$$
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
1147 AM CST Wed Feb 18 2015
.UPDATE...
ISSUED AT 1031 AM CST WED FEB 18 2015
Bitterly cold airmass settling into the Midwest as a low pressure
system moves out through the eastern Great Lakes. Pressure
gradient is increasing across the region as high pressure from the
Plains edges eastward. Increased pressure gradient resulting in
brisk NW sustained winds and 28-30kt winds aloft mixing down into
the higher gusts this morning. Deep synoptic trof over the Central
and Eastern CONUS this morning maintaining some cyclonic flow
aloft and a little bit of associated instability keeping some cu
development/possible flurries over the region for the afternoon.
No major changes anticipated in the forecast at this point but
will be making some small adjustments to freshen for the current
trends in a brief clearing of the sky and temps.
&&
.SHORT TERM...(Today)
ISSUED AT 329 AM CST WED FEB 18 2015
A compact shortwave that produced accumulating snows in our
southeast counties early this morning will depart to the southeast
by 5 am, leaving 1 to 2 inches of fluffy accumulation in its wake.
Additional lobes of energy in the strong NW flow aloft will likely
trigger flurries across the area today, but little additional
accumulation is expected. Any clearing that develops will likely see
some clouds reform, which could produce light snow in the strong cold
advection regime.
Northwest winds will increase into the 15 to 20 mph range with gusts
to 35 mph at times. That will cause blowing and drifting of the
fluffy snow that fell last night. Travel will be slippery today
across the area as a result.
Temps will struggle to climb much today, with a diurnal swing of
less than 5 degrees in many areas. Daytime highs will likely remain
in the single digits in northern areas and around 10 in the south.
The combo of wind and cold temps will put wind chills into advisory
levels this morning, and possibly through the afternoon as well.
Even if sustained winds don`t increase enough to produce wind chill
advisory criteria in some of our area, the gusts to 30+ mph will
push wind chills much colder from time to time. Therefore, since
bitter cold wind chills were expected tonight and Thursday as well,
and after collaboration with surrounding offices, we decided to
expand our current wind chill advisory for this morning to include
all of our counties and we extended it in time to include tonight
and Thursday morning.
&&
.LONG TERM...(Tonight through Tuesday)
ISSUED AT 329 AM CST WED FEB 18 2015
Wind chill advisory continues tonight through Thu morning across
central and southeast IL for wind chills of 15 to 25 below zero. A
few spots in the north and east will be flirting with wind chill
warning criteria of 25 below zero overnight until mid Thu morning.
Lows tonight in the single digits below zero as 850 temps down to
-25 to -27C. Highs Thu even a bit colder than today, only in the
upper single digits, to near 10F from Springfield sw despite mostly
sunny skies. Arctic high pressure over western Canada drops down
into IL by sunset Thu and this to lighten winds Thu & Thu night.
Another bitter cold night Thu night with lows ranging from 5 above
to 5 below zero with coldest readings in southeast IL and near IN
border.
Arctic high pressure drifts east across the Ohio river valley and
into the mid Atlantic states Friday while increasing warm air
advection and isentropic lift into central IL to develop chances of
light snow especially by Friday afternoon with mostly cloudy skies.
Highs Friday 20-25F with coldest readings in east central IL.
Extended models now showing surface low pressure lifting ne from the
southern plains across the Ohio river this weekend though timing
differences still exist with GFS model slower and linger more
precipitation over IL Sunday. Will stay close to guidance pops this
weekend which increases Sat and Sat night with likely pops in
southeast IL where a mixture of freezing rain, sleet, snow and even
rain occurs Sat and Sat evening. Also added chance of sleet with the
snow Friday night over southeast IL with freezing rain chances south
of highway 50 in southern IL. Storm system will tap into the Gulf of
Mexico and have ample moisture to work with and qpf amounts in
southeast IL are half to 1 inch with far southeast IL near
Lawrenceville over 1 inch. Storm system bears watching with snow
accumulations likely over central IL especially se of the IL river.
Sat has mildest highs in the 30s, then colder air ushers back into
the region early next week.
The Climate Prediction Center (CPC) Day 8-14 Outlook from Feb
25-Mar 3 continues greater than 60% chance of below normal
temperatures across IL. So winter cold looks to continue the next
two weeks.
&&
.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
ISSUED AT 1138 AM CST WED FEB 18 2015
Blustery and flurries through the afternoon with northwesterly
winds gusting to 30kts. Although many of the sites are currently
reporting VFR cigs, the MVFR cigs below 3kft are spreading as the
clouds develop. Have opted to start the TAF pd in MVFR as it will
be quickly. Same clouds present a bit of an issue for the
overnight hours. Whether or not that moisture is going to get
trapped as the sun sets this afternoon. Cold arctic high pressure
moving in with signif dwpt drops at the sfc...but lower dwpts not
here just yet. DVN sounding inversion this morning close to the
height of the developing deck. Instead of choosing for SKC or
OVC...have placed the cloud deck closer to the trof axis, and
deeper into the higher dwpts in CMI...clear for PIA to get out
from under todays clouds...and scattering down the middle.
Transition zone between up under the cloud deck and the clear
skies may present a narrow vis reduction as well if the dry air
advection slows too much after sunset.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY until Noon CST Thursday FOR ILZ027>031-
036>038-040>057-061>063-066>068-071>073.
&&
$$
UPDATE...HJS
SHORT TERM...Shimon
LONG TERM...07
AVIATION...HJS
Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1147 AM CST Wed Feb 18 2015
.UPDATE...
ISSUED AT 1031 AM CST WED FEB 18 2015
Bitterly cold airmass settling into the Midwest as a low pressure
system moves out through the eastern Great Lakes. Pressure
gradient is increasing across the region as high pressure from the
Plains edges eastward. Increased pressure gradient resulting in
brisk NW sustained winds and 28-30kt winds aloft mixing down into
the higher gusts this morning. Deep synoptic trof over the Central
and Eastern CONUS this morning maintaining some cyclonic flow
aloft and a little bit of associated instability keeping some cu
development/possible flurries over the region for the afternoon.
No major changes anticipated in the forecast at this point but
will be making some small adjustments to freshen for the current
trends in a brief clearing of the sky and temps.
&&
.SHORT TERM...(Today)
ISSUED AT 329 AM CST WED FEB 18 2015
A compact shortwave that produced accumulating snows in our
southeast counties early this morning will depart to the southeast
by 5 am, leaving 1 to 2 inches of fluffy accumulation in its wake.
Additional lobes of energy in the strong NW flow aloft will likely
trigger flurries across the area today, but little additional
accumulation is expected. Any clearing that develops will likely see
some clouds reform, which could produce light snow in the strong cold
advection regime.
Northwest winds will increase into the 15 to 20 mph range with gusts
to 35 mph at times. That will cause blowing and drifting of the
fluffy snow that fell last night. Travel will be slippery today
across the area as a result.
Temps will struggle to climb much today, with a diurnal swing of
less than 5 degrees in many areas. Daytime highs will likely remain
in the single digits in northern areas and around 10 in the south.
The combo of wind and cold temps will put wind chills into advisory
levels this morning, and possibly through the afternoon as well.
Even if sustained winds don`t increase enough to produce wind chill
advisory criteria in some of our area, the gusts to 30+ mph will
push wind chills much colder from time to time. Therefore, since
bitter cold wind chills were expected tonight and Thursday as well,
and after collaboration with surrounding offices, we decided to
expand our current wind chill advisory for this morning to include
all of our counties and we extended it in time to include tonight
and Thursday morning.
&&
.LONG TERM...(Tonight through Tuesday)
ISSUED AT 329 AM CST WED FEB 18 2015
Wind chill advisory continues tonight through Thu morning across
central and southeast IL for wind chills of 15 to 25 below zero. A
few spots in the north and east will be flirting with wind chill
warning criteria of 25 below zero overnight until mid Thu morning.
Lows tonight in the single digits below zero as 850 temps down to
-25 to -27C. Highs Thu even a bit colder than today, only in the
upper single digits, to near 10F from Springfield sw despite mostly
sunny skies. Arctic high pressure over western Canada drops down
into IL by sunset Thu and this to lighten winds Thu & Thu night.
Another bitter cold night Thu night with lows ranging from 5 above
to 5 below zero with coldest readings in southeast IL and near IN
border.
Arctic high pressure drifts east across the Ohio river valley and
into the mid Atlantic states Friday while increasing warm air
advection and isentropic lift into central IL to develop chances of
light snow especially by Friday afternoon with mostly cloudy skies.
Highs Friday 20-25F with coldest readings in east central IL.
Extended models now showing surface low pressure lifting ne from the
southern plains across the Ohio river this weekend though timing
differences still exist with GFS model slower and linger more
precipitation over IL Sunday. Will stay close to guidance pops this
weekend which increases Sat and Sat night with likely pops in
southeast IL where a mixture of freezing rain, sleet, snow and even
rain occurs Sat and Sat evening. Also added chance of sleet with the
snow Friday night over southeast IL with freezing rain chances south
of highway 50 in southern IL. Storm system will tap into the Gulf of
Mexico and have ample moisture to work with and qpf amounts in
southeast IL are half to 1 inch with far southeast IL near
Lawrenceville over 1 inch. Storm system bears watching with snow
accumulations likely over central IL especially se of the IL river.
Sat has mildest highs in the 30s, then colder air ushers back into
the region early next week.
The Climate Prediction Center (CPC) Day 8-14 Outlook from Feb
25-Mar 3 continues greater than 60% chance of below normal
temperatures across IL. So winter cold looks to continue the next
two weeks.
&&
.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
ISSUED AT 1138 AM CST WED FEB 18 2015
Blustery and flurries through the afternoon with northwesterly
winds gusting to 30kts. Although many of the sites are currently
reporting VFR cigs, the MVFR cigs below 3kft are spreading as the
clouds develop. Have opted to start the TAF pd in MVFR as it will
be quickly. Same clouds present a bit of an issue for the
overnight hours. Whether or not that moisture is going to get
trapped as the sun sets this afternoon. Cold arctic high pressure
moving in with signif dwpt drops at the sfc...but lower dwpts not
here just yet. DVN sounding inversion this morning close to the
height of the developing deck. Instead of choosing for SKC or
OVC...have placed the cloud deck closer to the trof axis, and
deeper into the higher dwpts in CMI...clear for PIA to get out
from under todays clouds...and scattering down the middle.
Transition zone between up under the cloud deck and the clear
skies may present a narrow vis reduction as well if the dry air
advection slows too much after sunset.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY until Noon CST Thursday FOR ILZ027>031-
036>038-040>057-061>063-066>068-071>073.
&&
$$
UPDATE...HJS
SHORT TERM...Shimon
LONG TERM...07
AVIATION...HJS
Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1041 AM CST Wed Feb 18 2015
.UPDATE...
ISSUED AT 1031 AM CST WED FEB 18 2015
Bitterly cold airmass settling into the Midwest as a low pressure
system moves out through the eastern Great Lakes. Pressure
gradient is increasing across the region as high pressure from the
Plains edges eastward. Increased pressure gradient resulting in
brisk NW sustained winds and 28-30kt winds aloft mixing down into
the higher gusts this morning. Deep synoptic trof over the Central
and Eastern CONUS this morning maintaining some cyclonic flow
aloft and a little bit of associated instability keeping some cu
development/possible flurries over the region for the afternoon.
No major changes anticipated in the forecast at this point but
will be making some small adjustments to freshen for the current
trends in a brief clearing of the sky and temps.
&&
.SHORT TERM...(Today)
ISSUED AT 329 AM CST WED FEB 18 2015
A compact shortwave that produced accumulating snows in our
southeast counties early this morning will depart to the southeast
by 5 am, leaving 1 to 2 inches of fluffy accumulation in its wake.
Additional lobes of energy in the strong NW flow aloft will likely
trigger flurries across the area today, but little additional
accumulation is expected. Any clearing that develops will likely see
some clouds reform, which could produce light snow in the strong cold
advection regime.
Northwest winds will increase into the 15 to 20 mph range with gusts
to 35 mph at times. That will cause blowing and drifting of the
fluffy snow that fell last night. Travel will be slippery today
across the area as a result.
Temps will struggle to climb much today, with a diurnal swing of
less than 5 degrees in many areas. Daytime highs will likely remain
in the single digits in northern areas and around 10 in the south.
The combo of wind and cold temps will put wind chills into advisory
levels this morning, and possibly through the afternoon as well.
Even if sustained winds don`t increase enough to produce wind chill
advisory criteria in some of our area, the gusts to 30+ mph will
push wind chills much colder from time to time. Therefore, since
bitter cold wind chills were expected tonight and Thursday as well,
and after collaboration with surrounding offices, we decided to
expand our current wind chill advisory for this morning to include
all of our counties and we extended it in time to include tonight
and Thursday morning.
&&
.LONG TERM...(Tonight through Tuesday)
ISSUED AT 329 AM CST WED FEB 18 2015
Wind chill advisory continues tonight through Thu morning across
central and southeast IL for wind chills of 15 to 25 below zero. A
few spots in the north and east will be flirting with wind chill
warning criteria of 25 below zero overnight until mid Thu morning.
Lows tonight in the single digits below zero as 850 temps down to
-25 to -27C. Highs Thu even a bit colder than today, only in the
upper single digits, to near 10F from Springfield sw despite mostly
sunny skies. Arctic high pressure over western Canada drops down
into IL by sunset Thu and this to lighten winds Thu & Thu night.
Another bitter cold night Thu night with lows ranging from 5 above
to 5 below zero with coldest readings in southeast IL and near IN
border.
Arctic high pressure drifts east across the Ohio river valley and
into the mid Atlantic states Friday while increasing warm air
advection and isentropic lift into central IL to develop chances of
light snow especially by Friday afternoon with mostly cloudy skies.
Highs Friday 20-25F with coldest readings in east central IL.
Extended models now showing surface low pressure lifting ne from the
southern plains across the Ohio river this weekend though timing
differences still exist with GFS model slower and linger more
precipitation over IL Sunday. Will stay close to guidance pops this
weekend which increases Sat and Sat night with likely pops in
southeast IL where a mixture of freezing rain, sleet, snow and even
rain occurs Sat and Sat evening. Also added chance of sleet with the
snow Friday night over southeast IL with freezing rain chances south
of highway 50 in southern IL. Storm system will tap into the Gulf of
Mexico and have ample moisture to work with and qpf amounts in
southeast IL are half to 1 inch with far southeast IL near
Lawrenceville over 1 inch. Storm system bears watching with snow
accumulations likely over central IL especially se of the IL river.
Sat has mildest highs in the 30s, then colder air ushers back into
the region early next week.
The Climate Prediction Center (CPC) Day 8-14 Outlook from Feb
25-Mar 3 continues greater than 60% chance of below normal
temperatures across IL. So winter cold looks to continue the next
two weeks.
&&
.AVIATION...(For the 12Z TAFS through 12Z Thursday morning)
ISSUED AT 600 AM CST WED FEB 18 2015
Shortwave energy aloft will keep clouds/flurries around today.
Cloud heights are generally low VFR, with MVFR clouds and brief
MVFR visibility in light snow around BMI and CMI. HRRR guidance
points toward a lowering of clouds heights in general this
afternoon, with 1500-2500 FT in most areas and scattered flurries.
The bulk of the upper energy should depart to the east by this
evening, leaving clearing skies later tonight.
Northwest winds will increase this morning into the 14-18kt range,
with gusts to 30kt at times today. The strong winds will cause
blowing and drifting of the fluffy snow that fell last night,
creating slippery travel surfaces today. Wind gusts will diminish
tonight as the pressure gradient weakens, but sustained winds will
remain in the 10-15kt range through the evening.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY until Noon CST Thursday FOR ILZ027>031-
036>038-040>057-061>063-066>068-071>073.
&&
$$
UPDATE...HJS
SHORT TERM...Shimon
LONG TERM...07
AVIATION...Shimon
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
813 AM CST WED FEB 18 2015
.SHORT TERM...
315 AM CST
THROUGH THURSDAY...
A MASSIVE UPPER LOW/TROUGH CENTERED OVER
NORTHERN ONTARIO CONTINUES TO BE SPREAD ACROSS MOST OF NORTH
AMERICA. AN EMBEDDED SHORTWAVE IS TRACKING SOUTHEAST ACROSS SOUTHERN
WISCONSIN/NORTHERN IOWA AND WILL CROSS THE LOCAL AREA THROUGH THE
MORNING. WATER VAPOR SHOWS SHARP RIDGING OVER THE WEST COAST
EXTENDING WELL INTO THE YUKON/NUNAVUT WITH A STRAIGHT NORTH/SOUTH
TRAJECTORY DOWN THE WEST FLANK OF THE BIG TROUGH INTO THE PLAINS.
EVENING UPPER AIR ANALYSIS SHOWS H85 TEMPS OF -28C INTO NORTHERN
MINNESOTA BEHIND THE APPROACHING SHORTWAVE AND ON TRACK TO WORK INTO
THE LOCAL AREA LATER TODAY. AT THE SURFACE...A BROAD AREA OF LOW
PRESSURE STRETCHES FROM WESTERN QUEBEC SOUTHWEST TO LAKE HURON WITH
A SECONDARY LOW CIRCULATION OVER LOWER MICHIGAN. A COLD FRONT
EXTENDS SOUTHWEST FROM THE CENTRAL WISCONSIN ACROSS IOWA AND WILL
CROSS THE AREA THIS MORNING. THE LARGER SCALE ASCENT AND THE INFLUX
OF COLD AIR IS DRIVING AREAS OF LIGHT SNOW WITH SOME EMBEDDED SNOW
SHOWERS. THIS ACTIVITY WILL WORK ACROSS THE AREA THROUGH MID
MORNING. OVERALL IT WILL REMAIN LIGHT BUT DO EXPECT MORE INTENSE
RETURNS TO BE EMBEDDED WITHIN THE BROADER AREA OF LIGHT
SNOW...ESPECIALLY AFTER DAYBREAK. A FEW TENTHS OF ACCUMULATION IS
POSSIBLE WITH THE MORE PERSISTENT SHOWERS WITH AROUND A HALF INCH
NOT OUT OF THE QUESTION GIVEN THAT THE SNOW WILL BE FLUFFY BUT MANY
AREAS MAY SEE LITTLE MORE THAN A DUSTING. CONTINUED COLD
ADVECTION/CYCLONIC FLOW WILL SUPPORT FLURRIES OR SOME LIGHT SNOW
THROUGH THE REST OF THE DAY ONCE THE MAIN WAVE HAS DEPARTED. LAKE
EFFECT SNOW SHOWERS WILL BE OCCURRING EAST OF LAKE MICHIGAN AND WILL
LIKELY PERIODICALLY AFFECT PORTIONS OF PORTER COUNTY. FAR NORTHEAST
SECTIONS ARE MOST FAVORED FOR LIGHT ACCUMULATION...POSSIBLY AROUND
AN INCH.
COLD ADVECTION WILL PERSIST THROUGH THE DAY. HIGH TEMPS WILL BE A
LITTLE TRICKY GIVEN THAT THERE WILL PROBABLY BE AT LEAST SOME BREAKS
OF SUNSHINE FROM LATE MORNING THROUGH THE AFTERNOON. THE CORE OF THE
COLDEST AIR DOES NOT ARRIVE UNTIL THIS EVENING SO THERE SHOULD BE AT
LEAST SOME MODEST RECOVERY FROM MORNING TEMPS BEFORE THEY LEVEL OFF
AND PROBABLY FALL SOMEWHAT DURING THE AFTERNOON. THIS WILL PUT HIGHS
IN THE SINGLE DIGITS FOR MOST AREAS THOUGH THE SOUTHEAST THIRD OF
THE AREA MAY SEE READINGS OF 10 OR JUST ABOVE. HIGH PRESSURE WILL BE
SPREADING INTO THE MISSISSIPPI RIVER VALLEY THROUGH TONIGHT KEEPING
THE LOCAL AREA IN THE PRESSURE GRADIENT BETWEEN IT AND LOW PRESSURE
TO THE EAST. THIS WILL KEEP A STEADY NORTHWEST BREEZE IN PLACE
KEEPING TEMPS FROM RADIATING OUT BUT LOWS WILL STILL BE BITTERLY
COLD IN THE -4 TO -10 OR SO RANGE. WIND CHILLS WILL BE PUSHED TO -20
TO -30 SO WILL ISSUE A WIND CHILL ADVISORY FROM THIS EVENING THROUGH
MUCH OF THURSDAY MORNING. THE BIG UPPER TROUGH WILL SHIFT EAST
THURSDAY ALLOWING FOR SOME WARMING OF THE MID LEVELS BY LATE DAY.
THE SURFACE HIGH WILL BE OVERHEAD BY AFTERNOON SO WEAK MIXING WILL
NOT BE ABLE TO TAKE ADVANTAGE OF THE WARMING ALOFT. THIS WILL LIKELY
KEEP HIGHS IN THE MID SINGLE DIGITS BUT THE WILD CARD WILL BE THE
SUN WHICH IS QUITE STRONG AND WITH AN OLD SNOW PACK MAY BE ABLE TO
PROVIDE AN EXTRA FEW DEGREES OVER FORECAST HIGHS. REGARDLESS IT WILL
BE COLD AND 3 OF THE 4 RECORD TEMPS OUTLINED BELOW WILL BE IN
JEOPARDY THURSDAY. WINDS WILL BE MUCH LIGHTER THURSDAY NIGHT
ALLOWING FOR BETTER RADIATIONAL COOLING BUT MID/HIGH CLOUDS WILL BE
APPROACHING FROM THE WEST WHICH COULD ALLOW FOR SOME WARMING LATE.
SOME NORTHERN AREAS MAY NEED A WIND CHILL ADVISORY WITH WIND CHILLS
IN THE LOWER MINUS 20S.
MDB
&&
.LONG TERM...
315 AM CST
FRIDAY THROUGH TUESDAY...
THE UPPER FLOW WILL BE FLATTENING FRIDAY AS
THE BIG TROUGH CONTINUES EAST AND A WEAK UPPER TROUGH WORKS
SOUTHEAST INTO THE NORTHERN PLAINS. WARM ADVECTION WILL CONTINUE
ALOFT AND WITH THE SURFACE HIGH SHIFTING EAST SOUTHERLY FLOW WILL
DEVELOP AT THE SURFACE LEADING TO A MODERATION OF TEMPS. THE WARM
ADVECTION IN ADVANCE OF THE UPPER TROUGH/CLIPPER WILL BRING
INCREASED CLOUD COVER AND MAYBE SOME LIGHT SNOW SO WILL CARRY LOW
POPS FRIDAY. THINGS BECOME MORE INTERESTING AND COMPLEX FRIDAY NIGHT
AND SATURDAY AS A LARGER SCALE TROUGH DIGS INTO THE DESERT
SOUTHWEST. THIS WILL TRIGGER SURFACE LOW DEVELOPMENT ACROSS TEXAS
WITH AN INVERTED TROUGH/WARM FRONT DEVELOPING TO THE NORTHEAST. THE
SFC LOW WILL LIFT NORTHEAST COMBINING WITH AN OPEN GULF TO BRING A
GOOD PUSH OF MOISTURE NORTHEAST WITH IT. THE SIGNAL FOR THIS SYSTEM
HAS BEEN IN PLACE FOR SEVERAL DAYS BUT TRACK/STRENGTH DETAILS HAVE
BEEN INCONSISTENT. TYPICALLY A FURTHER SOUTH TRACK WOULD BE FAVORED
COMING OUT OF SUCH A STRONG ARCTIC BLAST BUT WITH THE INITIAL
TROUGH/CLIPPER AND DE-AMPLIFICATION OF THE UPPER FLOW BEFORE THE
MAIN TROUGH DRIVING THIS SYSTEM COMES INTO PLAY THE MID LEVEL
THERMAL GRADIENT WILL BE ABLE TO BE PUSHED BACK TOWARD THE AREA. IT
SEEMS THAT GUIDANCE MAY CONTINUE TO FAVOR A NORTHWARD TREND...WHICH
HAS BEEN THE TREND WITH MOST OF THESE SOUTHERN SYSTEMS THIS WINTER.
THIS WILL BE SOMETHING TO WATCH AND FOR NOW SOUTHEAST AREAS WILL BE
AT GREATEST RISK TO HAVE PRECIP FALL SO WILL CONTINUE WITH HIGHEST
POPS IN THESE AREAS. TEMP DETAILS WILL ALSO DEPEND ON THE TRACK BUT
LOWER 30S LOOK GOOD FOR NOW...WITH PRECIP TYPE POSSIBLY BECOMING AN
ISSUE.
COLDER AIR WILL SPREAD IN BEHIND THIS SYSTEM AS CANADIAN HIGH
PRESSURE ONCE AGAIN MOVES INTO THE CENTRAL U.S. SEVERAL UPPER
TROUGHS/CLIPPERS LOOK TO CROSS THE REGION EARLY NEXT WEEK CARVING
OUT ANOTHER BIG UPPER TROUGH SO THE MILDER AIR OF FRIDAY/SATURDAY
WILL BE SHORT LIVED WITH COLDER THAN NORMAL ARCTIC AIR EXPECTED TO
TAKE OVER FOR MUCH OF NEXT WEEK. IN OTHER WORDS THE CONDITIONS OF
THE RECENT FEW DAYS LOOK TO BE REPEATED TEMP AND PRECIP WISE WITH
BOUTS OF LIGHT SNOW WITH EACH PASSING WAVE.
MDB
&&
.CLIMATE...
WHILE THE COLDEST AIR ALOFT ARRIVES WEDNESDAY...THE COLDEST SURFACE
TEMPERATURES MAY RESULT ON THURSDAY FEBRUARY 19TH...WHICH RIGHT NOW
APPEARS COULD JEOPARDIZE SOME RECORDS...ESPECIALLY THE RECORD LOW
MAXIMUM TEMPERATURES.
FEB 19TH
RECORD LOW RECORD LOW MAX
CHICAGO -7 (1936) 9 (1936)
ROCKFORD -16 (1979) 7 (1959)
MTF/RC
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 14Z...
* FLURRIES OR BRIEF LIGHT SNOW SHOWERS POSSIBLE AT ALMOST ANYTIME
TODAY.
* POSSIBILITY FOR A BRIEF WINDOW OF MVFR CEILINGS THIS MORNING.
* GUSTY NORTHWEST WINDS THROUGH AFTERNOON.
RODRIGUEZ/KJB
//DISCUSSION...UPDATED 12Z...
A FEW LIGHT SNOW SHOWERS AND FLURRIES WILL IMPACT THE TERMINALS
EARLY THIS MORNING AS AN UPPER LEVEL DISTURBANCE MOVES ACROSS THE
AREA. A FEW BRIEF PERIODS OF VISIBILITY RESTRICTS DOWN AROUND 2 TO 3
MILES IS POSSIBLE WITH THESE SNOW SHOWERS. HOWEVER...THIS WOULD BE
SHORT LIVED EARLY THIS MORNING. CIGS WILL ALSO LIKELY FALL DOWN
AROUND 2000 TO 2500 FEET FOR A PERIOD THIS MORNING WITH SOME OF
THESE SNOW SHOWERS. A FEW LINGERING FLURRIES ARE POSSIBLE
THEREAFTER...BUT NO REAL IMPACT IS EXPECTED. OTHERWISE...EXPECT
WINDS TO BECOME GUSTY UP TO AROUND 25 KT OUT OF THE NORTHWEST BY
LATE MORNING AND INTO THE AFTERNOON BEFORE ABATING BY EARLY
EVENING.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* MEDIUM CONFIDENCE IN TIMING OF SNOW SHOWER ACTIVITY.
* LOW MEDIUM CONFIDENCE OF BRIEF WINDOW OF MVFR CEILINGS.
* FAIRLY HIGH CONFIDENCE IN REMAINING FORECAST ELEMENTS.
RODRIGUEZ/KJB
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT...VFR. LIGHT AND VARIABLE WINDS.
FRIDAY...CHANCE OF SN WITH IFR POSSIBLE. MODERATELY STRONG SOUTH
WINDS.
SATURDAY...CHANCE OF MVFR/IFR AND SN.
SUNDAY...MVFR CIGS POSSIBLE. SLIGHT CHANCE OF -SN EARLY.
MONDAY...PRIMARILY VFR.
TUESDAY...SLIGHT CHANCE OF SNOW SHOWERS WITH MVFR TO IFR
POSSIBLE.
KJB
&&
.MARINE...
117 AM CST
A PERIOD OF STRONG NORTHWESTERLY WINDS IS STILL EXPECTED TO DEVELOP
ACROSS THE LAKE TODAY INTO TONIGHT. THE SURFACE PRESSURE GRADIENT
WILL TIGHTEN IN THE WAKE OF A SURFACE LOW...CURRENTLY SHIFTING
EASTWARD OVER THE UPPER GREAT LAKES REGION...AND AHEAD OF AN
ARCTIC SURFACE HIGH SHIFTING OVER THE NORTHERN PLAINS. IT APPEARS
THESE STRONG NORTHWEST WINDS WILL RANGE BETWEEN 30 KT AND SOME LOW
END 35 KT GALES...ESPECIALLY ACROSS THE SOUTHERN HALF OF LAKE
MICHIGAN. THE CURRENT HEADLINES FOR GALES AND FREEZING SPRAY
APPEAR TO BE ON TARGET...SO NO CHANGES ARE PLANNED AT THIS TIME.
HOWEVER...WE WILL NEED TO WATCH FOR THE POSSIBILITY OF A TIME
EXTENSION OF THE GALE/FREEZING SPRAY HEADLINE THROUGH THE NIGHT
TONIGHT...AS FORECAST GUIDANCE SUGGESTS THAT THE WINDS COULD
REMAIN ELEVATED THROUGH EARLY THURSDAY MORNING AS THE COLD ARCTIC
AIR MASS CONTINUES TO FILTER OVER THE LAKE.
WINDS WILL EASE FOR A PERIOD LATER THURSDAY AS THE SURFACE RIDGE OF
HIGH PRESSURE BEGINS TO SHIFT OVER THE WESTERN LAKES REGION.
HOWEVER...IT APPEARS THAT WINDS WILL QUICKLY PICK UP OUT OF THE
SOUTH BY FRIDAY AS ANOTHER CLIPPER SYSTEM TRACKS ACROSS SOUTHERN
CANADA. THIS LOOKS TO RESULT IN 30 KT SOUTHERLY WINDS AND MORE
FREEZING SPRAY LAKE-WIDE ON FRIDAY.
ANOTHER STORM SYSTEM LOOKS TO DEVELOP AND SHIFT SOUTH OF THE LAKE ON
SUNDAY. DEPENDING ON THE ACTUAL STRENGTHEN OF THIS SYSTEM...IT COULD
RESULT IN A PERIOD OF STRONG NORTHERLY WINDS DOWN THE LAKE.
HOWEVER...UNCERTAINTY IS STILL SOMEWHAT HIGH WITH THIS SYSTEM.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WIND CHILL ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-
ILZ023-ILZ032-ILZ033-ILZ039...6 PM WEDNESDAY TO NOON
THURSDAY.
IN...WIND CHILL ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019...6 PM
WEDNESDAY TO NOON THURSDAY.
LM...GALE WARNING...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-
LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 PM
WEDNESDAY.
HEAVY FREEZING SPRAY WARNING...LMZ080-LMZ567-LMZ669-LMZ671-
LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-
LMZ876-LMZ878 UNTIL 9 PM WEDNESDAY.
SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO BURNS HARBOR UNTIL
9 AM THURSDAY.
GALE WARNING...NEARSHORE BURNS HARBOR TO MICHIGAN CITY IN UNTIL 6 PM WEDNESDAY.
&&
$$
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Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
605 AM CST Wed Feb 18 2015
.SHORT TERM...(Today)
ISSUED AT 329 AM CST WED FEB 18 2015
A compact shortwave that produced accumulating snows in our
southeast counties early this morning will depart to the southeast
by 5 am, leaving 1 to 2 inches of fluffy accumulation in its wake.
Additional lobes of energy in the strong NW flow aloft will likely
trigger flurries across the area today, but little additional
accumulation is expected. Any clearing that develops will likely see
some clouds reform, which could produce light snow in the strong cold
advection regime.
Northwest winds will increase into the 15 to 20 mph range with gusts
to 35 mph at times. That will cause blowing and drifting of the
fluffy snow that fell last night. Travel will be slippery today
across the area as a result.
Temps will struggle to climb much today, with a diurnal swing of
less than 5 degrees in many areas. Daytime highs will likely remain
in the single digits in northern areas and around 10 in the south.
The combo of wind and cold temps will put wind chills into advisory
levels this morning, and possibly through the afternoon as well.
Even if sustained winds don`t increase enough to produce wind chill
advisory criteria in some of our area, the gusts to 30+ mph will
push wind chills much colder from time to time. Therefore, since
bitter cold wind chills were expected tonight and Thursday as well,
and after collaboration with surrounding offices, we decided to
expand our current wind chill advisory for this morning to include
all of our counties and we extended it in time to include tonight
and Thursday morning.
&&
.LONG TERM...(Tonight through Tuesday)
ISSUED AT 329 AM CST WED FEB 18 2015
Wind chill advisory continues tonight through Thu morning across
central and southeast IL for wind chills of 15 to 25 below zero. A
few spots in the north and east will be flirting with wind chill
warning criteria of 25 below zero overnight until mid Thu morning.
Lows tonight in the single digits below zero as 850 temps down to
-25 to -27C. Highs Thu even a bit colder than today, only in the
upper single digits, to near 10F from Springfield sw despite mostly
sunny skies. Arctic high pressure over western Canada drops down
into IL by sunset Thu and this to lighten winds Thu & Thu night.
Another bitter cold night Thu night with lows ranging from 5 above
to 5 below zero with coldest readings in southeast IL and near IN
border.
Arctic high pressure drifts east across the Ohio river valley and
into the mid Atlantic states Friday while increasing warm air
advection and isentropic lift into central IL to develop chances of
light snow especially by Friday afternoon with mostly cloudy skies.
Highs Friday 20-25F with coldest readings in east central IL.
Extended models now showing surface low pressure lifting ne from the
southern plains across the Ohio river this weekend though timing
differences still exist with GFS model slower and linger more
precipitation over IL Sunday. Will stay close to guidance pops this
weekend which increases Sat and Sat night with likely pops in
southeast IL where a mixture of freezing rain, sleet, snow and even
rain occurs Sat and Sat evening. Also added chance of sleet with the
snow Friday night over southeast IL with freezing rain chances south
of highway 50 in southern IL. Storm system will tap into the Gulf of
Mexico and have ample moisture to work with and qpf amounts in
southeast IL are half to 1 inch with far southeast IL near
Lawrenceville over 1 inch. Storm system bears watching with snow
accumulations likely over central IL especially se of the IL river.
Sat has mildest highs in the 30s, then colder air ushers back into
the region early next week.
The Climate Prediction Center (CPC) Day 8-14 Outlook from Feb
25-Mar 3 continues greater than 60% chance of below normal
temperatures across IL. So winter cold looks to continue the next
two weeks.
&&
.AVIATION...(For the 12Z TAFS through 12Z Thursday morning)
ISSUED AT 600 AM CST WED FEB 18 2015
Shortwave energy aloft will keep clouds/flurries around today.
Cloud heights are generally low VFR, with MVFR clouds and brief
MVFR visibility in light snow around BMI and CMI. HRRR guidance
points toward a lowering of clouds heights in general this
afternoon, with 1500-2500 FT in most areas and scattered flurries.
The bulk of the upper energy should depart to the east by this
evening, leaving clearing skies later tonight.
Northwest winds will increase this morning into the 14-18kt range,
with gusts to 30kt at times today. The strong winds will cause
blowing and drifting of the fluffy snow that fell last night,
creating slippery travel surfaces today. Wind gusts will diminish
tonight as the pressure gradient weakens, but sustained winds will
remain in the 10-15kt range through the evening.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY until Noon CST Thursday FOR ILZ027>031-
036>038-040>057-061>063-066>068-071>073.
&&
$$
SHORT TERM...Shimon
LONG TERM...07
AVIATION...Shimon
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
122 AM CST WED FEB 18 2015
.SHORT TERM...
320 PM CST
TONIGHT THROUGH THURSDAY...
MAIN CONCERN IS WITH BITTERLY COLD TEMPERATURES AND WIND CHILLS AS
NEAR RECORD COLD AIR MASS FOR MID TO LATE FEBRUARY IMPACTS THE AREA.
IN ADDITION...EXPECTING FAIRLY WIDESPREAD SNOW SHOWERS LATE TONIGHT
INTO WEDNESDAY MORNING.
MORNING RAOBS SHOWED HEART OF COLD AIR MASS...WITH 850 MB TEMPS OF
ABOUT -25 TO -30C FROM KINL UP TO HUDSON BAY. STRONG PV ANOMALY ON
LEADING EDGE OF THIS AIR MASS IS NOTED ON W/V IMAGERY FROM EASTERN
DAKOTAS INTO WESTERN ONTARIO AND THIS WILL MOVE OVER THE AREA
TONIGHT INTO EARLY THURSDAY. IN NEAR TERM...WILL CONTINUE TO SEE
OCCASIONAL FLURRIES...WITH LINGERING SNOW SHOWERS EXITING NW
INDIANA. FORCING FROM UPPER WAVE/PV ANOMALY AND STEEPENING OF
LAPSE RATES SHOULD RESULT IN FAIRLY WIDESPREAD SCATTERED SNOW
SHOWERS PIVOTING SOUTHEASTWARD FROM AROUND MIDNIGHT TONIGHT
THROUGH EARLY THURSDAY MORNING. SIMILAR TO PREVIOUS OCCURRENCES
WITHIN THE PAST WEEK...NOT ALL AREAS WILL SEE ACCUMULATIONS...BUT
WOULDNT BE SURPRISED IF HEAVIER SNOW SQUALLS ARE EMBEDDED WITHIN
SCATTERED SNOW SHOWER ACTIVITY...YIELDING LOCALLY 1/2 INCH TO 1
INCH ACCUMS AND SIGNIFICANTLY REDUCED VISIBILITY. COLD ADVECTION
SHOULD FORCE TEMPERATURES DOWN TO ROUGHLY 0 TO +6 RANGE BY
DAYBREAK WEDNESDAY.
TEMPERATURE TRENDS ARE TRICKY ON WEDNESDAY BECAUSE OF HOW ANOMALOUS
AIR MASS IS. MINUS MID TO UPPER 20S CELSIUS AIR MASS AT 850 MB PROGGED BY
LATE IN THE DAY IS AMONGST THE COLDEST OBSERVED AT ILX/DVN IN THE
MONTH OF FEBRUARY...AND ESPECIALLY THIS LATE IN THE MONTH. HAVE
SHOWN A VERY MINIMAL RECOVERY FROM MORNING LOWS INTO MID DAY/HIGHS
MID TO HIGH POSITIVE SINGLE DIGITS/FOLLOWED BY A FALL IN THE
AFTERNOON..BUT THIS VERY WELL COULD BE OVERDONE. BEST FORCING WILL
BE OFF TO EAST...BUT DEEP UPPER TROUGH REMAINING OVERHEAD AND STEEP
LOW LEVEL LAPSE RATES SHOULD KEEP AT LEAST ISOLATED SNOW SHOWERS AND
FLURRIES AROUND INTO EARLY WEDNESDAY AFTERNOON. STRONG LOW LEVEL
COLD ADVECTION WILL CONTINUE THROUGH WEDNESDAY NIGHT...WITH 925 MB
TEMPS IN THE MID MINUS 20S CELSIUS BY EARLY THURSDAY. THUS DESPITE HIGH
PRESSURE REMAINING WELL NORTHWEST AND PRECLUDING RADIATIONAL
COOLING...SUBZERO LOWS ARE EXPECTED CWA WIDE...AND RELATIVELY
UNIFORM RANGING FROM MID MINUS SINGLE DIGITS TO AROUND 10 BELOW.
EVEN DOWNTOWN CHICAGO SHOULD FALL TO SEVERAL DEGREES BELOW ZERO.
WILL NEED A WIND CHILL ADVISORY FOR THE ENTIRE CWA WEDNESDAY
EVENING/NIGHT THROUGH THURSDAY MORNING...WITH LOWEST VALUES
RANGING FROM 20 TO 30 BELOW ZERO.
THERMAL TROUGH WILL ONLY SLOWLY DEPART TO THE NORTHEAST ON
THURSDAY...SO AFTER BITTERLY COLD START TO DAY...CONTINUE TO
FORECAST RECORD/NEAR RECORD LOW HIGH TEMPERATURES IN THE LOW TO MID
POSITIVE SINGLE DIGITS. SEE CLIMATE SECTION FOR ADDITIONAL DETAILS.
REGARDING LAKE EFFECT POTENTIAL ON WEDNESDAY INTO WEDNESDAY
NIGHT...GUIDANCE CONTINUES TO FOCUS MAINLY EAST OF PORTER COUNTY
WITH WNW BOUNDARY LAYER FLOW. HOWEVER...WITH EXTREME COLD AIR MASS
OVER RELATIVELY MILD LAKE WATERS...COULD STILL SEE SOME MINOR
ACCUMULATIONS IN NORTHEAST PORTER COUNTY IN LIGHT MULTI-BAND SNOW
SHOWERS.
RC
&&
.LONG TERM...
355 PM CST
THURSDAY NIGHT THROUGH TUESDAY...
NO REAL END IN SIGHT TO THE COLD PATTERN...THOUGH THERE WILL BE
SOME MODERATION AT THE BEGINNING OF THE WEEKEND. THURSDAY NIGHT`S
LOWS WILL DEPEND ON HOW QUICKLY CLOUD COVER INCREASES FROM THE
WEST AND SOUTHWEST. ARCTIC HIGH WILL BE OVERHEAD FOR PART OF THE
NIGHT BEFORE SLIDING SOUTHEAST BY DAYBREAK. THERE WILL BE SLOW
WARM ADVECTION ALOFT...BUT ASSUMING SKIES REMAIN MOSTLY
CLEAR/PARTLY CLOUDY THROUGH AT LEAST PART OF
OVERNIGHT...RADIATIONAL COOLING WILL ENABLE SUBZERO LOWS CWA WIDE
AGAIN. COLDEST SPOTS IN NORTHERN IL COULD FALL TO 10 BELOW OR
SLIGHTLY LOWER. MUCH LIGHTER WINDS SHOULD PRECLUDE NEED FOR
ANOTHER WIND CHILL ADVISORY THURSDAY NIGHT.
ON FRIDAY INTO SATURDAY...BIT OF A COMPLEX SETUP WITH MODEL
VARIANCE REGARDING HANDLING MULTIPLE MID LEVEL SHORTWAVES. SOME 12Z
GUIDANCE BROUGHT ACROSS LEAD NORTHERN STREAM WAVE/CLIPPER ON
FRIDAY...FOR WHICH SLIGHT CHANCE TO LOW CHANCE (IN FAR) NORTH POPS
WERE CONTINUED. GFS OPERATIONAL/GEFS AND EUROPEAN ENSEMBLE THEN
INDICATE POTENTIAL FOR MORE WIDESPREAD PRECIPITATION FROM MID LEVEL
WAVE AND ASSOCIATED SURFACE LOW MOVING FROM SOUTHERN PLAINS TO
OHIO VALLEY ON SATURDAY INTO SUNDAY. DESPITE DRIER TREND TODAY
FROM OPERATIONAL ECMWF...OP GFS/GEFS MEAN AND INDIVIDUAL
MEMBERS/ECMWF ENSEMBLE MEAN AND SOME INDIVIDUAL MEMBERS/ALL HAVE
TRACK MORE FAVORABLE FOR WIDESPREAD SNOW AREA WIDE. FOR NOW HAVE
HIGHEST CHANCE POPS SOUTH OF INTERSTATE 80...BUT THIS PERIOD WILL
NEED TO BE WATCHED FOR HOW WELL VARIOUS SHORT WAVES
INTERACT/PHASE. HIGHS WILL MODERATE FROM NEAR/AROUND 20 ON FRIDAY
TO UPPER 20S/LOW 30S ON SATURDAY...THEN COOL BACK WELL BELOW
NORMAL FOR THE REST OF THE EXTENDED. 12Z OPERATIONAL ECMWF SHOWED
ANOTHER SHOT OF EXTREME COLD BEYOND DAY 7...WHICH ANYONE THAT IS
GROWING TIRED OF THE VERY COLD WEATHER CAN ONLY HOPE DOESNT COME
TO FRUITION.
RC
&&
.CLIMATE...
WHILE THE COLDEST AIR ALOFT ARRIVES WEDNESDAY...THE COLDEST SURFACE
TEMPERATURES MAY RESULT ON THURSDAY FEBRUARY 19TH...WHICH RIGHT NOW
APPEARS COULD JEOPARDIZE SOME RECORDS...ESPECIALLY THE RECORD LOW
MAXIMUM TEMPERATURES.
FEB 19TH
RECORD LOW RECORD LOW MAX
CHICAGO -7 (1936) 9 (1936)
ROCKFORD -16 (1979) 7 (1959)
MTF/RC
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* FLURRIES OR BRIEF LIGHT SNOW SHOWERS POSSIBLE AT ALMOST ANYTIME
THROUGH WEDNESDAY.
* BEST SHOT OF MORE SUBSTANTIAL SHSN APPEARS TO BE DURING THE
PREDAWN HOURS THROUGH EARLY MORNING WEDNESDAY.
* GUSTY NORTHWEST WINDS DEVELOP WEDNESDAY MORNING AND CONTINUE
THROUGH AFTERNOON.
KJB
//DISCUSSION...UPDATED 06Z...
PERIODS OF LIGHT SNOW SHOWERS AND FLURRIES ARE EXPECTED TO MOVE
ACROSS THE AREA OVER THE NEXT COUPLE HOURS. ALTHOUGH MOST OF THESE
WILL RESULT IN VERY MINIMAL VISIBILITY RESTRICTIONS...A FEW HEAVIER
SNOW SHOWERS COULD SET UP DURING THE PREDAWN HOURS...POSSIBLY
RESULTING IN A COUPLE SHORT PERIODS OF LOW END MVFR TO IFR
VISIBILITIES. SOME MINOR ACCUMULATIONS UP TO A HALF INCH ARE
POSSIBLE THROUGH EARLY MORNING.
WINDS THROUGH THE DAY WILL BE OUT OF THE NORTHWEST. EXPECT THESE
NORTHWEST WINDS TO BECOME GUSTY...UP TO AROUND 25 KT...BY LATE
MORNING AND INTO THE AFTERNOON BEFORE ABATING BY EARLY EVENING.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* MEDIUM CONFIDENCE IN TIMING OF BEST CHANCE OF MORE SUBSTANTIAL
SNOW SHOWER THREAT.
* FAIRLY HIGH CONFIDENCE IN REMAINING FORECAST ELEMENTS.
KJB
//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...
THURSDAY...VFR.
FRIDAY...VFR. MODERATELY STRONG SOUTH WINDS. BECOMING MVFR AT
NIGHT WITH SNOW/IFR POSSIBLE.
SATURDAY...MVFR CIGS POSSIBLE. CHANCE OF MVFR AND -SN.
SUNDAY...MVFR CIGS POSSIBLE.
MONDAY...PRIMARILY VFR.
IZZI
&&
.MARINE...
117 AM CST
A PERIOD OF STRONG NORTHWESTERLY WINDS IS STILL EXPECTED TO DEVELOP
ACROSS THE LAKE TODAY INTO TONIGHT. THE SURFACE PRESSURE GRADIENT
WILL TIGHTEN IN THE WAKE OF A SURFACE LOW...CURRENTLY SHIFTING
EASTWARD OVER THE UPPER GREAT LAKES REGION...AND AHEAD OF AN
ARCTIC SURFACE HIGH SHIFTING OVER THE NORTHERN PLAINS. IT APPEARS
THESE STRONG NORTHWEST WINDS WILL RANGE BETWEEN 30 KT AND SOME LOW
END 35 KT GALES...ESPECIALLY ACROSS THE SOUTHERN HALF OF LAKE
MICHIGAN. THE CURRENT HEADLINES FOR GALES AND FREEZING SPRAY
APPEAR TO BE ON TARGET...SO NO CHANGES ARE PLANNED AT THIS TIME.
HOWEVER...WE WILL NEED TO WATCH FOR THE POSSIBILITY OF A TIME
EXTENSION OF THE GALE/FREEZING SPRAY HEADLINE THROUGH THE NIGHT
TONIGHT...AS FORECAST GUIDANCE SUGGESTS THAT THE WINDS COULD
REMAIN ELEVATED THROUGH EARLY THURSDAY MORNING AS THE COLD ARCTIC
AIR MASS CONTINUES TO FILTER OVER THE LAKE.
WINDS WILL EASE FOR A PERIOD LATER THURSDAY AS THE SURFACE RIDGE OF
HIGH PRESSURE BEGINS TO SHIFT OVER THE WESTERN LAKES REGION.
HOWEVER...IT APPEARS THAT WINDS WILL QUICKLY PICK UP OUT OF THE
SOUTH BY FRIDAY AS ANOTHER CLIPPER SYSTEM TRACKS ACROSS SOUTHERN
CANADA. THIS LOOKS TO RESULT IN 30 KT SOUTHERLY WINDS AND MORE
FREEZING SPRAY LAKE-WIDE ON FRIDAY.
ANOTHER STORM SYSTEM LOOKS TO DEVELOP AND SHIFT SOUTH OF THE LAKE ON
SUNDAY. DEPENDING ON THE ACTUAL STRENGTHEN OF THIS SYSTEM...IT COULD
RESULT IN A PERIOD OF STRONG NORTHERLY WINDS DOWN THE LAKE.
HOWEVER...UNCERTAINTY IS STILL SOMEWHAT HIGH WITH THIS SYSTEM.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...HEAVY FREEZING SPRAY WARNING...LMZ080-LMZ567-LMZ669-LMZ671-
LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-
LMZ876-LMZ878...6 AM WEDNESDAY TO 9 PM WEDNESDAY.
GALE WARNING...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-
LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...6 AM
WEDNESDAY TO 9 PM WEDNESDAY.
GALE WARNING...LMZ745...9 AM WEDNESDAY TO 6 PM WEDNESDAY.
SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744...9 AM
WEDNESDAY TO 6 PM WEDNESDAY.
&&
$$
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Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1134 PM CST Tue Feb 17 2015
.UPDATE...
ISSUED AT 903 PM CST TUE FEB 17 2015
Light snow is moving into the area this evening and will continue
during the overnight hours. Very difficult to see all of it on
radar given how shallow the clouds are and that all radars are
overshooting it out in northeast MO and west central IL. So, based
on observations, it appears most of the light snow will be along
and south of I-74. So will be making adjustments to pop/wx grids
to accommodate expected location of snowfall. Short term models:
HRRR seems too fast with pushing the snow through. First glance at
the NAM looks ok and keeps snow going in the east and southeast
overnight. Clouds and winds look fine, but will be making some
minor adjustments to low temps. Update will be out shortly.
&&
.SHORT TERM...(Tonight)
ISSUED AT 320 PM CST TUE FEB 17 2015
Slightly complicated forecast in the short term as the long wave
trof rotates around and through the region tonight, with a couple
shortwaves on satellite imagery. HRRR and RUC/RAPP both producing
more qpf with prev runs and clearly picking up on some snow showers
out to the west. NAM/GFS picking up on it, but mainly concentrating
on wave to the south. As a result, two additions to tonights
forecast...one with the southwest CWA in a line from roughly
Jacksonville to Springfield to Paris...potential for a few tenths of
snowfall. Up to an inch possible, but better chances will be to the
south, where the second change to the forecast is with the more
southerly wave...an inch/inch and a half are possible. Behind the
snow as morning approaches, the northwesterly winds will continue to
increase. Temperatures will mainly run slightly off the normal
diurnal curve as the cold air mass moves southward into the region.
By early morning hours, wind chills will drop to -10 to -15F NW of
the Illinois River Valley.
&&
.LONG TERM...(Wednesday through Tuesday)
ISSUED AT 320 PM CST TUE FEB 17 2015
Another reinforcing push of cold air will move into central Illinois
behind another pressure trough early Wednesday. Very cold arctic air
will result in highs only in the single digits with brisk northwest
winds 15-20 mph and gusts to around 30 mph. Went below MOS guidance
for highs Wed due to extreme variation from climatology and due to
snow cover over portions of the forecast area. As a result, wind
chill values will be below -15 F for much of the area northwest of
the Illinois River and have issued a wind chill advisory from 5 a.m.
to noon. Wind chill temperatures should be just above wind chill
criteria...-10 F or so for the afternoon, but still very cold. Winds
will settle down somewhat overnight Wednesday night causing
temperatures to drop below zero throughout central IL, but wind
chills look to drop to around -15 to -20 F and may need another wind
chill advisory.
Deep upper level trof shifts east of IL Thu night and Friday while
arctic high pressure also drifts east of IL across the Ohio river
valley Thu night and Fri morning. Temps will be slow to climb on
Friday due to mostly cloudy skies with highs in the low to mid 20s.
Have small chances of light snow Friday afternoon as moist warm
advection affects the region.
Extended models coming to better agreement on track of southern
stream storm system this weekend, with track of low passing the
southern tip of Illinois Saturday. Looks cold enough for mainly
light snow, though continue with a mix over southeast IL on Sat.
Have just slight chance of light snow Sunday and then dry across
area by Sunday evening. Highs in the low to mid 30s Sat cool off
again early next week on Sunday and Monday behind this storm
system.
&&
.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
ISSUED AT 1134 PM CST TUE FEB 17 2015
Mainly MVFR and some IFR conditions occurring currently as a
couple of narrow bands of moderate snow moves across the TAF
sites. They have passed PIA and will pass SPI and BMI and DEC in
the next 1-2 hrs. Could be 2 more hours before CMI sees the
moderate snow pass. During the passage, vis and cigs drop to
IFR/LIFR levels, but for only a brief period. So TEMPO groups for
next 1-2 hours will have IFR type conditions with very poor vis
with snow. Once this passes, conditions will improve to VFR with
possible breaks in the clouds. So going to have broken clouds.
Believe more CU/SC will develop tomorrow and become broken across
the area. With the broken clouds, flurries will be possible, so
have included them at all sites for most of the day tomorrow. Cigs
will remain low and broken tomorrow evening. Winds will be
northwesterly through the period, but have seen brief gusty
north winds with snow band, but this will be very brief, so will
not add to TAFs. Northwest winds will become gusty again tomorrow
with gusts up to 27kts. Then winds decrease during the evening
after 00z.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY from 5 AM to Noon CST Wednesday FOR
ILZ027>029-036-040.
&&
$$
UPDATE...Auten
SHORT TERM...HJS
LONG TERM...Onton
AVIATION...Auten
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
340 PM EST WED FEB 18 2015
.SYNOPSIS...
ISSUED AT 425 AM EST WED FEB 18 2015
PERIODS OF LAKE EFFECT SNOW...HEAVIEST ACROSS FAR NORTH-CENTRAL
INDIANA AND SOUTHWEST LOWER MICHIGAN...WILL CREATE HAZARDOUS
DRIVING CONDITIONS TODAY...TONIGHT AND THURSDAY. AFTERNOON HIGH
TEMPERATURES WILL ONLY REACH THE TEENS. LOWS TONIGHT WILL RANGE
FROM A FEW DEGREES ABOVE ZERO NEAR LAKE MICHIGAN TO ZERO TO TEN
BELOW ZERO AWAY FROM THE LAKE. DANGEROUS WIND CHILLS ARE ALSO
EXPECTED BY LATER TODAY THROUGH FRIDAY MORNING...GENERALLY
RANGING BETWEEN 10 BELOW AND 25 BELOW ZERO. SNOW CHANCES RETURN
TO THE ENTIRE AREA LATER THIS WEEKEND AS A POTENTIAL WINTER STORM
MOVES INTO THE OHIO VALLEY.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 336 PM EST WED FEB 18 2015
ELONGATED SFC TROUGH LEFTOVER FM EARLIER MESOVORT THAT DISSIPATED
THROUGH WRN LWR MI STILL SUSTAINING AN INTENSE BAND OF LK EFFECT
SNOW FM SERN LAGRANGE NWWD THROUGH WRN ST JOE. WWD OF THIS PRIMARY
BAND...LESS INTENSE MULTIBANDS CONT TO DVLP W/SOMEWHAT GREATER
ORGANIZATION NOTED ACRS WRN CASS SEWD THROUGH ERN ELKHART.
OUTSIDE THESE AREAS...DRY ENTRAINMENT TAKING ITS TOLL ON DIURNAL
ENHANCEMENT TRYING TO DVLP SOUTH OF HIGHWAY 30 AND SUSPECT LTL IF
ANYTHING WILL MATERIALIZE NOW PRIOR TO SUNSET AND LOSS OF LIMITED
DIURNAL HEATING.
OF NOTE GOING FWD IS XPCD REDVLPMNT OF PRIMARY SINGLE BAND AS CLD
LYR FLW VEERS OVERNIGHT AND LL THERMAL TROUGH MAXIMIZES. BASED ON
EARLY MORNING DVLPMNT/EVOLUTION AND IN LIGHT OF 12Z NAM/CONCURRENT
LTR RUC TRENDS...ANOTHER INTENSE SINGLE BAND XPCD TO DVLP TWD 06Z
ALG THE ERN SHORELINE OF WRN LWR MI AND THEN SHIFT SWD INTO NW IN BY
DAYBREAK THU BFR STALLING OUT NW-SE NORTH OF THE HIGHWAY 30 CORRIDOR
BFR BREAKING UP TWD THU EVENING. WILL ADJUST HIGHLITES TO ADD A
BUFFER STRIP OF SNOW/BLWG SNOW ADVISORY COUNTIES...KOSCIUSKO EAST
THROUGH STEUBEN/DEKALB TO ALIGN W/SRN EXTENT OF LIGHT SNOW SHOWERS
AND MORE SIG GRADIENT FLW THROUGH 03Z.
&&
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 336 PM EST WED FEB 18 2015
...WEEKEND SYSTEM TO BRING POTENTIAL MIXED PRECIPIATION...
FORECAST PERIOD BEGINS WITH DIMINISHING LES AS INITIAL SETUP AT 00Z
FRI WITH 3-4KFT INVERSION HEIGHTS AND DELTA T OF 25-30C AND SLIGHTLY
VEERING NW FLOW OF 290-330 UNDER THE INVERSION WILL QUICKLY
DISSIPATE AS SURFACE RIDGE AXIS SHIFTS EASTWARD OVER THE AREA.
MODELS OFFERING VARYING SOLUTIONS ON TIMING AND PLACEMENT OF SYSTEMS
ARRIVING THIS WEEKEND. WEAK NORTHERN STREAM CLIPPER WILL APPROACH
THE GREAT LAKES REGION FRIDAY AND OFFER LITTLE MORE THAN
SLIGHT/CHANCE POPS DURING THE DAY FRIDAY. SOUTHERN STREAM SYSTEM
WILL THEN MOVE UP INTO THE TN/OH VALLEY ON SATURDAY. MODELS CONTINUE
TO TREND MORE TOWARDS THE NW WITH TRACK OF SFC LOW WITH GEM MOST
AGGRESSIVE ON PRECIP WITH OVER 1.5 INCHES...ECMWF AND GFS LOWER BUT
STILL RESPECTABLE. WITH TRENDS POINTING TOWARD HIGHER CONFIDENCE IN
CHANCES FOR MEASURABLE PRECIP...HAVE INCREASED POPS SUBSTANTIALLY
SATURDAY AFTERNOON AND NIGHT WITH CAT POPS SE SAT NGT. AS FOR PTYPE
AND AMOUNTS...FURTHER NORTH TRACK WILL INTRODUCE GREATER MIX
POTENTIAL SAT AFTN/EVE ESPECIALLY S/SE PORTIONS AS HIGHS MAY CLIMB
ABOVE FREEZING SAT AFTERNOON AND POSSIBLY HOLD INTO THE EVENING.
FOR NOW HAVE WENT WITH RAIN OR SNOW SATURDAY AFTERNOON WITH LIKELY
NEED TO EXPAND INTO PARTS OF SAT NGT IN LATER FORECASTS. COULD
BECOME QUITE MESSY FOR MUCH OF THE WEEKEND SO STAY TUNED FOR LATER
UPDATES.
FEW CHANGES TO PERIODS BEYOND THE WEEKEND WITH EFFECTS OF THE
WEEKEND SYSTEM POSSIBLY DICTATING AMOUNT/SPEED OF COLD AIR RETURN TO
THE REGION AND IMPACTS IN TERMS OF LAKE EFFECT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1237 PM EST WED FEB 18 2015
LK EFFECT SNOW IMPACTING KSBN AND W/APPRECIABLE UPTICK IN GRADIENT FLW
XPC LIFR CONDS TO PERSIST THROUGH THIS AFTN BFR ABATING SOMEWHAT
LT THIS AFTN AND EVENING. HWVR SECONDARY INTENSE SINGLE BAND
DVLPMNT XPCD TO REFOCUS WWD OF CURRENT BAND LT TONIGHT AND CARRY
SWD THROUGH THU AM. HAVE BASICALLY THINGS DOWN W/HEAVY SNOW LIKELY
AT THE TERMINAL ALTHOUGH 18Z FCST TIMING IS LIKELY TOO OPTIMISTIC
AND WILL NEED TO BE BUMPED BACK MORE TWD 09Z.
KFWA ATTM REMAINS OUTSIDE ANY POTENTIAL LK EFFECT IMPACTS. HWVR
INCREASINGLY MOIST AND UNSTABLE BNDRY LYR XPCD ON THU AS LL
THERMAL TROUGH MAXIMIZES AND GREATER CLD LYR VEERING OCCURS OVR
THE LAKE. THIS SHLD RESULT IN A PD OF MVFR OR PERHAPS IFR CONDS AT
KFWA JUST AFT 18Z THU. WILL ADDRESS IN LTR FCSTS.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...WIND CHILL ADVISORY UNTIL NOON EST /11 AM CST/ THURSDAY FOR
INZ007>009-012>018-020-022>027-032>034.
WINTER WEATHER ADVISORY UNTIL 7 PM EST /6 PM CST/ THURSDAY FOR
INZ003>006.
WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR
INZ007>009-016.
MI...WIND CHILL ADVISORY UNTIL NOON EST THURSDAY FOR MIZ080-081.
WINTER WEATHER ADVISORY UNTIL 7 PM EST THURSDAY FOR MIZ079.
WINTER STORM WARNING UNTIL 7 PM EST THURSDAY FOR MIZ077-078.
OH...WIND CHILL ADVISORY UNTIL NOON EST THURSDAY FOR OHZ001-002-004-
005-015-016-024-025.
LM...NONE.
&&
$$
SYNOPSIS...STEINWEDEL
SHORT TERM...T
LONG TERM...FISHER
AVIATION...T
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AREA FORECAST DISCUSSION
NWS DES MOINES IA
1211 PM CST WED FEB 18 2015
.SHORT TERM /TODAY/...
ISSUED AT 311 AM CST WED FEB 18 2015
ARCTIC FRONT WILL CONTINUE TO PUSH SOUTH AND SHOULD
EXIT THE STATE BY 12Z AT THE LATEST. WELL ADVERTISED COLD SNAP IS
HERE AND THE STRONG CAA LOOKS TO PERSIST THROUGHOUT THE DAY
BEFORE GRADUALLY RELAXING PAST 21Z AS THE SURFACE HIGH BUILDS INTO
THE REGION. MIXING TO AROUND 925 TO 900MB WHERE TEMPS RANGE FROM
-18C TO -23C DEPICTED BY THE HIRES ARW/NMM...WITH THE NMM SLIGHTLY
COLDER. ECMWF IS WARMEST WRT TO MAX TEMPS TODAY DESPITE AGREEING
WITH THE NAM/GFS ON 925MB TEMPS. THE LATEST HRRR KEEPS THE
NORTHEAST NEAR OR SLIGHTLY BELOW ZERO THROUGH 20Z AND CERTAINLY DO
NOT EXPECT MUCH OF A WARMUP B/T 20-00Z. LEANED TOWARD THE RAP/SREF
FOR MAX TEMPS...ESPECIALLY ACROSS THE NORTHEAST TO EAST TODAY.
THIS RESULTED IN SLIGHTLY LOWERING MAX TEMPS IN THE NORTHEAST AND
LITTLE CHANGE ELSEWHERE.
POTENTIAL FOR A FEW AREAS ACROSS THE NORTH FROM MCW TO ALO TO
REACH WIND CHILL WARNING CRITERIA (-30F) FOR A SHORT STINT THIS
MORNING...BUT LOOKS TO BE BORDERLINE AND NOT TO LAST MUCH LONGER
THAN 3 HOURS AND FELT THE CURRENT WIND CHILL ADVISORY WAS SUFFICE.
WIND CHILL ADVISORY CRITERIA IS STILL BEING MET PAST 18Z TODAY AND
MAY NEED TO EXTEND THE ADVISORY ACROSS THE NORTHEAST.
.LONG TERM /TONIGHT THROUGH TUESDAY/...
ISSUED AT 311 AM CST WED FEB 18 2015
MAIN CHALLENGES THROUGH THE PERIOD WILL INCLUDE IMMEDIATE COLD
TEMPERATURES...BRIEF WARMING INTO THE EARLY PORTION OF THE WEEKEND
AND CONTINUATION OF LARGE SCALE H500 ANCHOR LOW THROUGH THE
REMAINDER OF THE EXTENDED WITH A FEW WRINKLES ALONG THE WAY. AS
SURFACE RIDGE AXIS SETTLES INTO THE AREA TONIGHT/EARLY THURSDAY WITH
CLEAR SKIES...TEMPERATURES WILL DROP SIGNIFICANTLY OVER THE
REGION...ESPECIALLY THE COLD PRONE AREAS NEAR US HIGHWAY 20 AND THE
IOWA RIVER VALLEY. HAVE LOWERED MINS THERE TONIGHT WITH EXPECTATION
THAT WITH LINGERING SNOW COVER TEMPS WILL BOTTOM TO NEAR 15 BELOW AT
KALO BY MORNING. DURING THE DAY THURSDAY TEMPERATURES WILL RECOVER
WEST AS WARM AIR ADVECTION INCREASES. MOST OF THE MODELS CONTINUE TO
SHOW A QUICK HIT OF LIGHT SNOW AS THE WARM FRONT PROGRESSES EAST
THURSDAY NIGHT AND FRIDAY. ISENTROPIC LIFT OVER A DEVELOPING
H850/H700 FRONT ALOFT FOCUSES THE LIGHT SNOW JUST EAST OF THE
BOUNDARY. HAVE INCREASED POP TO HIGH CHANCE/LOW LIKELY CAT FOR NOW
WITH ROUGHLY A HALF INCH TO INCH OF LIGHT SNOW DURING THE EVENT.
THOUGH MOST OF THE SNOW WILL FALL OVERNIGHT...TRAVEL MAY BE IMPACTED
FROM I80 EAST FRIDAY MORNING DUE TO A LIGHT DUSTING OF VERY POWDERY
SNOW ON AREA ROADS. INCREASING SOUTH WINDS MAY CAUSE SOME MINOR
BLOWING SNOW FRIDAY MORNING. BY LATE DAY FRIDAY MILDER AIR WILL MOVE
ACROSS THE REGION LIFTING AFTERNOON HIGHS INTO THE MID 20S EAST TO
MID 30S WEST AS H850 TEMPS RECOVER TO -4C EAST TO NEAR 0C SOUTHWEST.
ALSO OF NOTE BY LATE FRIDAY...THE EURO HAS A WAVE OVER THE ROCKIES
DIGGING SOUTH TOWARD THE OK PANHANDLE THEN MOVING EAST. THIS INDUCES
SFC LOW DEVELOPMENT OVER TEXAS WHICH THEN MOVES EAST NORTHEAST. BOTH
THE EURO/GEM ARE TRENDING SOUTH WITH THIS SYSTEM WHILE THE GFS IS
CURRENTLY FARTHER NORTH TAKING THE NORTHERN PRECIPITATION SHIELD
INTO SOUTHERN IOWA. THOUGH SOME UNCERTAINTY REMAINS...THE
PREDOMINANT STREAM THIS SEASON HAS REMAINED THE SOUTHERN STREAM AND
FAVOR THE MORE SOUTHERN SOLUTIONS AT THIS TIME...THAT AND THE
ADVERTISED COLD FRONT THAT WILL MOVE SOUTH OF THE AREA SATURDAY AS
ANOTHER ARCTIC HIGH OVER MANITOBA CANADA SLOWLY DRIFTS SOUTH INTO
IOWA BY MONDAY. THIS SHOULD HELP SUPPRESS THE STORM TRACK TO SOUTH
OF THE STATE. THE ADVANCING HIGH WILL RESULT IN MUCH COLDER
CONDITIONS BY SUNDAY NIGHT WITH SUB ZERO LOWS ONCE AGAIN AND HIGHS
RECOVERING ONLY INTO THE UPPER TEENS TO LOWER 20S ON MONDAY. WITH
THE PARENT ANCHOR LOW OVER HUDSON BAY CANADA AND PLENTY OF UPSTREAM
ENERGY... AND CROSS POLAR FLOW...THERE WILL BE YET ANOTHER
VIGOROUS SHORT WAVE CLIPPER WILL RACING SOUTHEAST TOWARD THE
GREAT LAKES TUESDAY. DESPITE SOME TIMING DIFFERENCES IN THE MODELS
WITH THE GFS BEING ITS USUAL QUICK SELF...THE END RESULT WILL
LIKELY BE THE SAME. ANOTHER EXCEPTIONALLY COLD AIRMASS WILL ARRIVE
BY LATE IN THE EXTENDED PERIOD WITH THE LOWEST THICKNESS VALUES
RANGING FROM 486DM TO 492DM OVER WI/MN/MI BY MIDDAY TUESDAY.
THOUGH THE COLDEST AIR LOOKS TO BE JUST EAST OF IOWA...I SUSPECT
DOUBLE DIGIT BELOW ZERO OVERNIGHT LOWS ONCE AGAIN OVER PORTIONS OF
THE FORECAST AREA BY DAY 7 NIGHT IF THE CURRENT PROGS HOLD. BOTTOM
LINE...BETWEEN TODAY AND NEXT TUESDAY WE SHOULD EXPERIENCE A TOTAL
OF 3 ARCTIC INTRUSIONS FROM THE CENTRAL PLAINS AND GREAT
LAKES...EAST ALL THE WAY TO NEW ENGLAND. EXPECT MORE WIND AND
BITTER COLD.
&&
.AVIATION...18/18Z
ISSUED AT 1118 AM CST WED FEB 18 2015
HIGH PRESSURE WILL KEEP CONDITIONS PRIMARILY VFR THROUGH PERIOD.
WILL SEE MVFR CEILINGS EARLY IN PERIOD AT EASTERN SITES
KMCW/KALO/KOTM BEFORE PUSHING EAST. NORTHWESTERLY WINDS WILL BE
STRONG AND GUSTY THROUGH 00Z...WITH GUSTS UP TO 30KTS POSSIBLE AT
TIMES. WINDS WILL DECREASE AND BECOME MORE NORTHERLY AFTER 00Z.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...PODRAZIK
LONG TERM...REV
AVIATION...AWB
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1121 AM CST WED FEB 18 2015
.SHORT TERM /TODAY/...
ISSUED AT 311 AM CST WED FEB 18 2015
ARCTIC FRONT WILL CONTINUE TO PUSH SOUTH AND SHOULD
EXIT THE STATE BY 12Z AT THE LATEST. WELL ADVERTISED COLD SNAP IS
HERE AND THE STRONG CAA LOOKS TO PERSIST THROUGHOUT THE DAY
BEFORE GRADUALLY RELAXING PAST 21Z AS THE SURFACE HIGH BUILDS INTO
THE REGION. MIXING TO AROUND 925 TO 900MB WHERE TEMPS RANGE FROM
-18C TO -23C DEPICTED BY THE HIRES ARW/NMM...WITH THE NMM SLIGHTLY
COLDER. ECMWF IS WARMEST WRT TO MAX TEMPS TODAY DESPITE AGREEING
WITH THE NAM/GFS ON 925MB TEMPS. THE LATEST HRRR KEEPS THE
NORTHEAST NEAR OR SLIGHTLY BELOW ZERO THROUGH 20Z AND CERTAINLY DO
NOT EXPECT MUCH OF A WARMUP B/T 20-00Z. LEANED TOWARD THE RAP/SREF
FOR MAX TEMPS...ESPECIALLY ACROSS THE NORTHEAST TO EAST TODAY.
THIS RESULTED IN SLIGHTLY LOWERING MAX TEMPS IN THE NORTHEAST AND
LITTLE CHANGE ELSEWHERE.
POTENTIAL FOR A FEW AREAS ACROSS THE NORTH FROM MCW TO ALO TO
REACH WIND CHILL WARNING CRITERIA (-30F) FOR A SHORT STINT THIS
MORNING...BUT LOOKS TO BE BORDERLINE AND NOT TO LAST MUCH LONGER
THAN 3 HOURS AND FELT THE CURRENT WIND CHILL ADVISORY WAS SUFFICE.
WIND CHILL ADVISORY CRITERIA IS STILL BEING MET PAST 18Z TODAY AND
MAY NEED TO EXTEND THE ADVISORY ACROSS THE NORTHEAST.
.LONG TERM /TONIGHT THROUGH TUESDAY/...
ISSUED AT 311 AM CST WED FEB 18 2015
MAIN CHALLENGES THROUGH THE PERIOD WILL INCLUDE IMMEDIATE COLD
TEMPERATURES...BRIEF WARMING INTO THE EARLY PORTION OF THE WEEKEND
AND CONTINUATION OF LARGE SCALE H500 ANCHOR LOW THROUGH THE
REMAINDER OF THE EXTENDED WITH A FEW WRINKLES ALONG THE WAY. AS
SURFACE RIDGE AXIS SETTLES INTO THE AREA TONIGHT/EARLY THURSDAY WITH
CLEAR SKIES...TEMPERATURES WILL DROP SIGNIFICANTLY OVER THE
REGION...ESPECIALLY THE COLD PRONE AREAS NEAR US HIGHWAY 20 AND THE
IOWA RIVER VALLEY. HAVE LOWERED MINS THERE TONIGHT WITH EXPECTATION
THAT WITH LINGERING SNOW COVER TEMPS WILL BOTTOM TO NEAR 15 BELOW AT
KALO BY MORNING. DURING THE DAY THURSDAY TEMPERATURES WILL RECOVER
WEST AS WARM AIR ADVECTION INCREASES. MOST OF THE MODELS CONTINUE TO
SHOW A QUICK HIT OF LIGHT SNOW AS THE WARM FRONT PROGRESSES EAST
THURSDAY NIGHT AND FRIDAY. ISENTROPIC LIFT OVER A DEVELOPING
H850/H700 FRONT ALOFT FOCUSES THE LIGHT SNOW JUST EAST OF THE
BOUNDARY. HAVE INCREASED POP TO HIGH CHANCE/LOW LIKELY CAT FOR NOW
WITH ROUGHLY A HALF INCH TO INCH OF LIGHT SNOW DURING THE EVENT.
THOUGH MOST OF THE SNOW WILL FALL OVERNIGHT...TRAVEL MAY BE IMPACTED
FROM I80 EAST FRIDAY MORNING DUE TO A LIGHT DUSTING OF VERY POWDERY
SNOW ON AREA ROADS. INCREASING SOUTH WINDS MAY CAUSE SOME MINOR
BLOWING SNOW FRIDAY MORNING. BY LATE DAY FRIDAY MILDER AIR WILL MOVE
ACROSS THE REGION LIFTING AFTERNOON HIGHS INTO THE MID 20S EAST TO
MID 30S WEST AS H850 TEMPS RECOVER TO -4C EAST TO NEAR 0C SOUTHWEST.
ALSO OF NOTE BY LATE FRIDAY...THE EURO HAS A WAVE OVER THE ROCKIES
DIGGING SOUTH TOWARD THE OK PANHANDLE THEN MOVING EAST. THIS INDUCES
SFC LOW DEVELOPMENT OVER TEXAS WHICH THEN MOVES EAST NORTHEAST. BOTH
THE EURO/GEM ARE TRENDING SOUTH WITH THIS SYSTEM WHILE THE GFS IS
CURRENTLY FARTHER NORTH TAKING THE NORTHERN PRECIPITATION SHIELD
INTO SOUTHERN IOWA. THOUGH SOME UNCERTAINTY REMAINS...THE
PREDOMINANT STREAM THIS SEASON HAS REMAINED THE SOUTHERN STREAM AND
FAVOR THE MORE SOUTHERN SOLUTIONS AT THIS TIME...THAT AND THE
ADVERTISED COLD FRONT THAT WILL MOVE SOUTH OF THE AREA SATURDAY AS
ANOTHER ARCTIC HIGH OVER MANITOBA CANADA SLOWLY DRIFTS SOUTH INTO
IOWA BY MONDAY. THIS SHOULD HELP SUPPRESS THE STORM TRACK TO SOUTH
OF THE STATE. THE ADVANCING HIGH WILL RESULT IN MUCH COLDER
CONDITIONS BY SUNDAY NIGHT WITH SUB ZERO LOWS ONCE AGAIN AND HIGHS
RECOVERING ONLY INTO THE UPPER TEENS TO LOWER 20S ON MONDAY. WITH
THE PARENT ANCHOR LOW OVER HUDSON BAY CANADA AND PLENTY OF UPSTREAM
ENERGY... AND CROSS POLAR FLOW...THERE WILL BE YET ANOTHER
VIGOROUS SHORT WAVE CLIPPER WILL RACING SOUTHEAST TOWARD THE
GREAT LAKES TUESDAY. DESPITE SOME TIMING DIFFERENCES IN THE MODELS
WITH THE GFS BEING ITS USUAL QUICK SELF...THE END RESULT WILL
LIKELY BE THE SAME. ANOTHER EXCEPTIONALLY COLD AIRMASS WILL ARRIVE
BY LATE IN THE EXTENDED PERIOD WITH THE LOWEST THICKNESS VALUES
RANGING FROM 486DM TO 492DM OVER WI/MN/MI BY MIDDAY TUESDAY.
THOUGH THE COLDEST AIR LOOKS TO BE JUST EAST OF IOWA...I SUSPECT
DOUBLE DIGIT BELOW ZERO OVERNIGHT LOWS ONCE AGAIN OVER PORTIONS OF
THE FORECAST AREA BY DAY 7 NIGHT IF THE CURRENT PROGS HOLD. BOTTOM
LINE...BETWEEN TODAY AND NEXT TUESDAY WE SHOULD EXPERIENCE A TOTAL
OF 3 ARCTIC INTRUSIONS FROM THE CENTRAL PLAINS AND GREAT
LAKES...EAST ALL THE WAY TO NEW ENGLAND. EXPECT MORE WIND AND
BITTER COLD.
&&
.AVIATION...18/18Z
ISSUED AT 1118 AM CST WED FEB 18 2015
HIGH PRESSURE WILL KEEP CONDITIONS PRIMARILY VFR THROUGH PERIOD.
WILL SEE MVFR CEILINGS EARLY IN PERIOD AT EASTERN SITES
KMCW/KALO/KOTM BEFORE PUSHING EAST. NORTHWESTERLY WINDS WILL BE
STRONG AND GUSTY THROUGH 00Z...WITH GUSTS UP TO 30KTS POSSIBLE AT
TIMES. WINDS WILL DECREASE AND BECOME MORE NORTHERLY AFTER 00Z.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY UNTIL NOON CST TODAY FOR ADAIR-ADAMS-
APPANOOSE-AUDUBON-BLACK HAWK-BOONE-BREMER-BUTLER-CALHOUN-CARROLL-
CASS-CERRO GORDO-CLARKE-CRAWFORD-DALLAS-DAVIS-DECATUR-EMMET-
FRANKLIN-GREENE-GRUNDY-GUTHRIE-HAMILTON-HANCOCK-HARDIN-HUMBOLDT-
JASPER-KOSSUTH-LUCAS-MADISON-MAHASKA-MARION-MARSHALL-MONROE-PALO
ALTO-POCAHONTAS-POLK-POWESHIEK-RINGGOLD-SAC-STORY-TAMA-TAYLOR-
UNION-WAPELLO-WARREN-WAYNE-WEBSTER-WINNEBAGO-WORTH-WRIGHT.
&&
$$
SHORT TERM...PODRAZIK
LONG TERM...REV
AVIATION...AWB
AREA FORECAST DISCUSSION
NWS DES MOINES IA
542 AM CST WED FEB 18 2015
...UPDATED AVIATION DISCUSSION...
.SHORT TERM /TODAY/...
ISSUED AT 311 AM CST WED FEB 18 2015
ARCTIC FRONT WILL CONTINUE TO PUSH SOUTH AND SHOULD
EXIT THE STATE BY 12Z AT THE LATEST. WELL ADVERTISED COLD SNAP IS
HERE AND THE STRONG CAA LOOKS TO PERSIST THROUGHOUT THE DAY
BEFORE GRADUALLY RELAXING PAST 21Z AS THE SURFACE HIGH BUILDS INTO
THE REGION. MIXING TO AROUND 925 TO 900MB WHERE TEMPS RANGE FROM
-18C TO -23C DEPICTED BY THE HIRES ARW/NMM...WITH THE NMM SLIGHTLY
COLDER. ECMWF IS WARMEST WRT TO MAX TEMPS TODAY DESPITE AGREEING
WITH THE NAM/GFS ON 925MB TEMPS. THE LATEST HRRR KEEPS THE
NORTHEAST NEAR OR SLIGHTLY BELOW ZERO THROUGH 20Z AND CERTAINLY DO
NOT EXPECT MUCH OF A WARMUP B/T 20-00Z. LEANED TOWARD THE RAP/SREF
FOR MAX TEMPS...ESPECIALLY ACROSS THE NORTHEAST TO EAST TODAY.
THIS RESULTED IN SLIGHTLY LOWERING MAX TEMPS IN THE NORTHEAST AND
LITTLE CHANGE ELSEWHERE.
POTENTIAL FOR A FEW AREAS ACROSS THE NORTH FROM MCW TO ALO TO
REACH WIND CHILL WARNING CRITERIA (-30F) FOR A SHORT STINT THIS
MORNING...BUT LOOKS TO BE BORDERLINE AND NOT TO LAST MUCH LONGER
THAN 3 HOURS AND FELT THE CURRENT WIND CHILL ADVISORY WAS SUFFICE.
WIND CHILL ADVISORY CRITERIA IS STILL BEING MET PAST 18Z TODAY AND
MAY NEED TO EXTEND THE ADVISORY ACROSS THE NORTHEAST.
.LONG TERM /TONIGHT THROUGH TUESDAY/...
ISSUED AT 311 AM CST WED FEB 18 2015
MAIN CHALLENGES THROUGH THE PERIOD WILL INCLUDE IMMEDIATE COLD
TEMPERATURES...BRIEF WARMING INTO THE EARLY PORTION OF THE WEEKEND
AND CONTINUATION OF LARGE SCALE H500 ANCHOR LOW THROUGH THE
REMAINDER OF THE EXTENDED WITH A FEW WRINKLES ALONG THE WAY. AS
SURFACE RIDGE AXIS SETTLES INTO THE AREA TONIGHT/EARLY THURSDAY WITH
CLEAR SKIES...TEMPERATURES WILL DROP SIGNIFICANTLY OVER THE
REGION...ESPECIALLY THE COLD PRONE AREAS NEAR US HIGHWAY 20 AND THE
IOWA RIVER VALLEY. HAVE LOWERED MINS THERE TONIGHT WITH EXPECTATION
THAT WITH LINGERING SNOW COVER TEMPS WILL BOTTOM TO NEAR 15 BELOW AT
KALO BY MORNING. DURING THE DAY THURSDAY TEMPERATURES WILL RECOVER
WEST AS WARM AIR ADVECTION INCREASES. MOST OF THE MODELS CONTINUE TO
SHOW A QUICK HIT OF LIGHT SNOW AS THE WARM FRONT PROGRESSES EAST
THURSDAY NIGHT AND FRIDAY. ISENTROPIC LIFT OVER A DEVELOPING
H850/H700 FRONT ALOFT FOCUSES THE LIGHT SNOW JUST EAST OF THE
BOUNDARY. HAVE INCREASED POP TO HIGH CHANCE/LOW LIKELY CAT FOR NOW
WITH ROUGHLY A HALF INCH TO INCH OF LIGHT SNOW DURING THE EVENT.
THOUGH MOST OF THE SNOW WILL FALL OVERNIGHT...TRAVEL MAY BE IMPACTED
FROM I80 EAST FRIDAY MORNING DUE TO A LIGHT DUSTING OF VERY POWDERY
SNOW ON AREA ROADS. INCREASING SOUTH WINDS MAY CAUSE SOME MINOR
BLOWING SNOW FRIDAY MORNING. BY LATE DAY FRIDAY MILDER AIR WILL MOVE
ACROSS THE REGION LIFTING AFTERNOON HIGHS INTO THE MID 20S EAST TO
MID 30S WEST AS H850 TEMPS RECOVER TO -4C EAST TO NEAR 0C SOUTHWEST.
ALSO OF NOTE BY LATE FRIDAY...THE EURO HAS A WAVE OVER THE ROCKIES
DIGGING SOUTH TOWARD THE OK PANHANDLE THEN MOVING EAST. THIS INDUCES
SFC LOW DEVELOPMENT OVER TEXAS WHICH THEN MOVES EAST NORTHEAST. BOTH
THE EURO/GEM ARE TRENDING SOUTH WITH THIS SYSTEM WHILE THE GFS IS
CURRENTLY FARTHER NORTH TAKING THE NORTHERN PRECIPITATION SHIELD
INTO SOUTHERN IOWA. THOUGH SOME UNCERTAINTY REMAINS...THE
PREDOMINANT STREAM THIS SEASON HAS REMAINED THE SOUTHERN STREAM AND
FAVOR THE MORE SOUTHERN SOLUTIONS AT THIS TIME...THAT AND THE
ADVERTISED COLD FRONT THAT WILL MOVE SOUTH OF THE AREA SATURDAY AS
ANOTHER ARCTIC HIGH OVER MANITOBA CANADA SLOWLY DRIFTS SOUTH INTO
IOWA BY MONDAY. THIS SHOULD HELP SUPPRESS THE STORM TRACK TO SOUTH
OF THE STATE. THE ADVANCING HIGH WILL RESULT IN MUCH COLDER
CONDITIONS BY SUNDAY NIGHT WITH SUB ZERO LOWS ONCE AGAIN AND HIGHS
RECOVERING ONLY INTO THE UPPER TEENS TO LOWER 20S ON MONDAY. WITH
THE PARENT ANCHOR LOW OVER HUDSON BAY CANADA AND PLENTY OF UPSTREAM
ENERGY... AND CROSS POLAR FLOW...THERE WILL BE YET ANOTHER
VIGOROUS SHORT WAVE CLIPPER WILL RACING SOUTHEAST TOWARD THE
GREAT LAKES TUESDAY. DESPITE SOME TIMING DIFFERENCES IN THE MODELS
WITH THE GFS BEING ITS USUAL QUICK SELF...THE END RESULT WILL
LIKELY BE THE SAME. ANOTHER EXCEPTIONALLY COLD AIRMASS WILL ARRIVE
BY LATE IN THE EXTENDED PERIOD WITH THE LOWEST THICKNESS VALUES
RANGING FROM 486DM TO 492DM OVER WI/MN/MI BY MIDDAY TUESDAY.
THOUGH THE COLDEST AIR LOOKS TO BE JUST EAST OF IOWA...I SUSPECT
DOUBLE DIGIT BELOW ZERO OVERNIGHT LOWS ONCE AGAIN OVER PORTIONS OF
THE FORECAST AREA BY DAY 7 NIGHT IF THE CURRENT PROGS HOLD. BOTTOM
LINE...BETWEEN TODAY AND NEXT TUESDAY WE SHOULD EXPERIENCE A TOTAL
OF 3 ARCTIC INTRUSIONS FROM THE CENTRAL PLAINS AND GREAT
LAKES...EAST ALL THE WAY TO NEW ENGLAND. EXPECT MORE WIND AND
BITTER COLD.
&&
.AVIATION...18/12Z
ISSUED AT 526 AM CST WED FEB 18 2015
STRONG CAA WILL CONTINUE THROUGH THE AFTERNOON. HAVE VFR CIGS/VIS
MENTIONED DURING ENTIRE TAF PERIOD.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY UNTIL NOON CST TODAY FOR ADAIR-ADAMS-
APPANOOSE-AUDUBON-BLACK HAWK-BOONE-BREMER-BUTLER-CALHOUN-CARROLL-
CASS-CERRO GORDO-CLARKE-CRAWFORD-DALLAS-DAVIS-DECATUR-EMMET-
FRANKLIN-GREENE-GRUNDY-GUTHRIE-HAMILTON-HANCOCK-HARDIN-HUMBOLDT-
JASPER-KOSSUTH-LUCAS-MADISON-MAHASKA-MARION-MARSHALL-MONROE-PALO
ALTO-POCAHONTAS-POLK-POWESHIEK-RINGGOLD-SAC-STORY-TAMA-TAYLOR-
UNION-WAPELLO-WARREN-WAYNE-WEBSTER-WINNEBAGO-WORTH-WRIGHT.
&&
$$
SHORT TERM...PODRAZIK
LONG TERM...REV
AVIATION...PODRAZIK
AREA FORECAST DISCUSSION
NWS DES MOINES IA
312 AM CST WED FEB 18 2015
.SHORT TERM /TODAY/...
ISSUED AT 311 AM CST WED FEB 18 2015
ARCTIC FRONT WILL CONTINUE TO PUSH SOUTH AND SHOULD
EXIT THE STATE BY 12Z AT THE LATEST. WELL ADVERTISED COLD SNAP IS
HERE AND THE STRONG CAA LOOKS TO PERSIST THROUGHOUT THE DAY BEFORE
GRADUALLY RELAXING PAST 21Z AS THE SURFACE HIGH BUILDS INTO THE
REGION. MIXING TO AROUND 925 TO 900MB WHERE TEMPS RANGE FROM -18C TO
-23C DEPICTED BY THE HIRES ARW/NMM...WITH THE NMM SLIGHTLY COLDER.
ECMWF IS WARMEST WRT TO MAX TEMPS TODAY DESPITE AGREEING WITH THE
NAM/GFS ON 925MB TEMPS. THE LATEST HRRR KEEPS THE NORTHEAST NEAR OR
SLIGHTLY BELOW ZERO THROUGH 20Z AND CERTAINLY DO NOT EXPECT MUCH OF A
WARMUP B/T 20-00Z. LEANED TOWARD THE RAP/SREF FOR MAX
TEMPS...ESPECIALLY ACROSS THE NORTHEAST TO EAST TODAY. THIS RESULTED
IN SLIGHTLY LOWERING MAX TEMPS IN THE NORTHEAST AND LITTLE CHANGE
ELSEWHERE.
POTENTIAL FOR A FEW AREAS ACROSS THE NORTH FROM MCW TO ALO TO REACH
WIND CHILL WARNING CRITERIA (-30F) FOR A SHORT STINT THIS
MORNING...BUT LOOKS TO BE BORDERLINE AND NOT TO LAST MUCH LONGER
THAN 3 HOURS AND FELT THE CURRENT WIND CHILL ADVISORY WAS SUFFICE.
WIND CHILL ADVISORY CRITERIA IS STILL BEING MET PAST 18Z TODAY AND
MAY NEED TO EXTEND THE ADVISORY ACROSS THE NORTHEAST.
.LONG TERM /TONIGHT THROUGH TUESDAY/...
ISSUED AT 311 AM CST WED FEB 18 2015
MAIN CHALLENGES THROUGH THE PERIOD WILL INCLUDE IMMEDIATE COLD
TEMPERATURES...BRIEF WARMING INTO THE EARLY PORTION OF THE WEEKEND
AND CONTINUATION OF LARGE SCALE H500 ANCHOR LOW THROUGH THE
REMAINDER OF THE EXTENDED WITH A FEW WRINKLES ALONG THE WAY. AS
SURFACE RIDGE AXIS SETTLES INTO THE AREA TONIGHT/EARLY THURSDAY WITH
CLEAR SKIES...TEMPERATURES WILL DROP SIGNIFICANTLY OVER THE
REGION...ESPECIALLY THE COLD PRONE AREAS NEAR US HIGHWAY 20 AND THE
IOWA RIVER VALLEY. HAVE LOWERED MINS THERE TONIGHT WITH EXPECTATION
THAT WITH LINGERING SNOW COVER TEMPS WILL BOTTOM TO NEAR 15 BELOW AT
KALO BY MORNING. DURING THE DAY THURSDAY TEMPERATURES WILL RECOVER
WEST AS WARM AIR ADVECTION INCREASES. MOST OF THE MODELS CONTINUE TO
SHOW A QUICK HIT OF LIGHT SNOW AS THE WARM FRONT PROGRESSES EAST
THURSDAY NIGHT AND FRIDAY. ISENTROPIC LIFT OVER A DEVELOPING
H850/H700 FRONT ALOFT FOCUSES THE LIGHT SNOW JUST EAST OF THE
BOUNDARY. HAVE INCREASED POP TO HIGH CHANCE/LOW LIKELY CAT FOR NOW
WITH ROUGHLY A HALF INCH TO INCH OF LIGHT SNOW DURING THE EVENT.
THOUGH MOST OF THE SNOW WILL FALL OVERNIGHT...TRAVEL MAY BE IMPACTED
FROM I80 EAST FRIDAY MORNING DUE TO A LIGHT DUSTING OF VERY POWDERY
SNOW ON AREA ROADS. INCREASING SOUTH WINDS MAY CAUSE SOME MINOR
BLOWING SNOW FRIDAY MORNING. BY LATE DAY FRIDAY MILDER AIR WILL MOVE
ACROSS THE REGION LIFTING AFTERNOON HIGHS INTO THE MID 20S EAST TO
MID 30S WEST AS H850 TEMPS RECOVER TO -4C EAST TO NEAR 0C SOUTHWEST.
ALSO OF NOTE BY LATE FRIDAY...THE EURO HAS A WAVE OVER THE ROCKIES
DIGGING SOUTH TOWARD THE OK PANHANDLE THEN MOVING EAST. THIS INDUCES
SFC LOW DEVELOPMENT OVER TEXAS WHICH THEN MOVES EAST NORTHEAST. BOTH
THE EURO/GEM ARE TRENDING SOUTH WITH THIS SYSTEM WHILE THE GFS IS
CURRENTLY FARTHER NORTH TAKING THE NORTHERN PRECIPITATION SHIELD
INTO SOUTHERN IOWA. THOUGH SOME UNCERTAINTY REMAINS...THE
PREDOMINANT STREAM THIS SEASON HAS REMAINED THE SOUTHERN STREAM AND
FAVOR THE MORE SOUTHERN SOLUTIONS AT THIS TIME...THAT AND THE
ADVERTISED COLD FRONT THAT WILL MOVE SOUTH OF THE AREA SATURDAY AS
ANOTHER ARCTIC HIGH OVER MANITOBA CANADA SLOWLY DRIFTS SOUTH INTO
IOWA BY MONDAY. THIS SHOULD HELP SUPPRESS THE STORM TRACK TO SOUTH
OF THE STATE. THE ADVANCING HIGH WILL RESULT IN MUCH COLDER
CONDITIONS BY SUNDAY NIGHT WITH SUB ZERO LOWS ONCE AGAIN AND HIGHS
RECOVERING ONLY INTO THE UPPER TEENS TO LOWER 20S ON MONDAY. WITH
THE PARENT ANCHOR LOW OVER HUDSON BAY CANADA AND PLENTY OF UPSTREAM
ENERGY... AND CROSS POLAR FLOW...THERE WILL BE YET ANOTHER
VIGOROUS SHORT WAVE CLIPPER WILL RACING SOUTHEAST TOWARD THE
GREAT LAKES TUESDAY. DESPITE SOME TIMING DIFFERENCES IN THE MODELS
WITH THE GFS BEING ITS USUAL QUICK SELF...THE END RESULT WILL
LIKELY BE THE SAME. ANOTHER EXCEPTIONALLY COLD AIRMASS WILL ARRIVE
BY LATE IN THE EXTENDED PERIOD WITH THE LOWEST THICKNESS VALUES
RANGING FROM 486DM TO 492DM OVER WI/MN/MI BY MIDDAY TUESDAY.
THOUGH THE COLDEST AIR LOOKS TO BE JUST EAST OF IOWA...I SUSPECT
DOUBLE DIGIT BELOW ZERO OVERNIGHT LOWS ONCE AGAIN OVER PORTIONS OF
THE FORECAST AREA BY DAY 7 NIGHT IF THE CURRENT PROGS HOLD. BOTTOM
LINE...BETWEEN TODAY AND NEXT TUESDAY WE SHOULD EXPERIENCE A TOTAL
OF 3 ARCTIC INTRUSIONS FROM THE CENTRAL PLAINS AND GREAT
LAKES...EAST ALL THE WAY TO NEW ENGLAND. EXPECT MORE WIND AND
BITTER COLD.
&&
.AVIATION...18/06Z
ISSUED AT 1130 PM CST TUE FEB 17 2015
WIND SURGE IS MAKING ITS WAY ACROSS NORTHWEST IOWA AND WILL PASS
THROUGH THE TERMINALS WITHIN THE NEXT FEW HOURS...BRINGING
STRONGER NORTHWEST WINDS THROUGH THE MORNING HOURS. A NARROW BAND
OF MVFR CIGS AND ISOLD SW- WILL ACCOMPANY THE SURGE...MAINLY AT
FOD AND ALO...BUT ANY LOW CIGS/VSBYS WILL BE AOA FL020/3SM AND
LAST ONLY AN HOUR OR TWO AT MOST. THEREAFTER...EXPECT MOSTLY CLEAR
SKIES WITH WINDS GRADUALLY DIMINISHING ON WED AFTERNOON.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY UNTIL NOON CST TODAY FOR ADAIR-ADAMS-
APPANOOSE-AUDUBON-BLACK HAWK-BOONE-BREMER-BUTLER-CALHOUN-CARROLL-
CASS-CERRO GORDO-CLARKE-CRAWFORD-DALLAS-DAVIS-DECATUR-EMMET-
FRANKLIN-GREENE-GRUNDY-GUTHRIE-HAMILTON-HANCOCK-HARDIN-HUMBOLDT-
JASPER-KOSSUTH-LUCAS-MADISON-MAHASKA-MARION-MARSHALL-MONROE-PALO
ALTO-POCAHONTAS-POLK-POWESHIEK-RINGGOLD-SAC-STORY-TAMA-TAYLOR-
UNION-WAPELLO-WARREN-WAYNE-WEBSTER-WINNEBAGO-WORTH-WRIGHT.
&&
$$
SHORT TERM...PODRAZIK
LONG TERM...REV
AVIATION...LEE
AREA FORECAST DISCUSSION
NWS GOODLAND KS
857 PM MST THU FEB 19 2015
.UPDATE...
ISSUED AT 857 PM MST THU FEB 19 2015
UPDATED FORECAST TO ADJUST TIMING OF RAIN/SNOW TRANSITION TOMORROW
NIGHT BASED ON LATEST FORECAST GUIDANCE. TAKING A CLOSER LOOK AT
INSTABILITY FRIDAY EVENING...IT IS INTERESTING TO NOTE FORECAST
LAPSE RATES...SOUNDING PROFILES AND THE STRENGTH OF THIS SHORTWAVE
MOVING IN. WOULD NOT BE SURPRISED IF A FEW RUMBLES OF THUNDER WERE
OBSERVED...POSSIBLY EVEN A COUPLE LIGHTNING STRIKES. HAVE NOT
PLACED THIS IN THE GRIDS YET BUT WANTED TO MENTION THE POSSIBILITY
HERE. MADE A SLIGHT ADJUSTMENT TO SNOWFALL GRIDS BASED ON THIS
CHANGE IN TIMING. OVERALL...TOTALS REMAIN LARGELY UNCHANGED.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 217 PM MST THU FEB 19 2015
WATER VAPOR IMAGERY INDICATED A PLUME OF MOISTURE MOVING BETWEEN THE
LARGE UPPER LEVEL TROUGH OVER THE NORTHEAST AND THE UPPER LEVEL
RIDGE POSITIONED OVER MEXICO. THIS MOISTURE WAS BRINGING SOME DENSE
UPPER LEVEL CLOUDS FOR PORTIONS OF CENTRAL AND SOUTHWEST NEBRASKA.
ELSEWHERE...CLOUD COVER WAS MOSTLY CLEAR.
A STEADY STREAM OF WATER VAPOR MOISTURE WILL CONTINUE TO STREAM
BETWEEN THE UPPER LEVEL TROUGH OVER THE NORTHEAST AND THE UPPER
RIDGE OVER MEXICO...WHICH WILL BRING CLOUD COVER FOR NORTH CENTRAL
KANSAS AND SOUTH CENTRAL NEBRASKA LATE THIS AFTERNOON. CLOUD COVER
WILL DISSIPATE THIS EVENING AS DRY AIR SETTLES INTO THE REGION.
ALTHOUGH CLOUD COVER TONIGHT WILL BE LACKING...SOUTHERLY WINDS WILL
KEEP LOW TEMPERATURES WARMER IN THE MID TO UPPER 20S.
FRIDAY WILL BE ANOTHER WARMER THAN AVERAGE DAY IN THE LOW TO MID 50S
AHEAD OF A COLD SURGE OF AIR ASSOCIATED WITH THE NEXT WINTER STORM
TO AFFECT THE TRI STATE AREA. A POCKET OF POTENTIAL VORTICITY AHEAD
OF AN UPPER LEVEL TROUGH SLIDING DOWN THE FRONT RANGE OF THE ROCKIES
WILL BRING INCREASED CLOUD COVER FOR LOCATIONS NORTH OF INTERSTATE
70 BY THE EARLY AFTERNOON. OVERCAST CONDITIONS WILL BE ACROSS THE
ENTIRE FORECAST AREA BY LATE AFTERNOON WITH SOME PRECIPITATION
BEGINNING TO MOVE INTO EASTERN COLORADO AND SOUTHWEST NEBRASKA. WITH
850 TEMPS ABOVE FREEZING...CRITICAL 850-700 MB THICKNESSES ABOVE
1540 METERS AND SURFACE TEMPERATURES ABOVE FREEZING...EXPECTING
PRECIPITATION TO START AS RAIN. RAIN WILL BEGIN TO TRANSITION TO A
RAIN SNOW MIX LATER INTO THE EVENING HOURS.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 217 PM MST THU FEB 19 2015
A LARGE UPPER TROUGH WILL PUSH SOUTH INTO THE MID SECTION OF THE
CONUS FRIDAY NIGHT AND SATURDAY AND THEN START SPLITTING SUNDAY.
THE ENERGY IS ADVERTISED TO SPLIT TOWARDS NORTHERN CALIFORNIA AND
THE GREAT LAKES WITH SOME RIDGING OVER THE CENTRAL PLAINS. A
SURFACE TROUGH WILL EXIST OVER THE CENTRAL AND NORTHERN PLAINS
FRIDAY NIGHT AND THEN SHIFT EAST SATURDAY. SURFACE HIGH PRESSURE
WILL MOVE INTO THE CENTRAL PLAINS BEHIND THE EXITING TROUGH WITH A
COLD FRONT ENTERING NORTHWEST KANSAS AS EARLY AS LATE SATURDAY
AFTERNOON.
PLAN TO ISSUE A WINTER STORM WATCH FOR EASTERN COLORADO FROM
SATURDAY EVENING THROUGH SUNDAY NIGHT FOR THE HIGHER SNOW AMOUNTS
OVER THOSE COUNTIES. (SEE DETAILS BELOW)
THE GFS AND NAM ARE IN DECENT AGREEMENT ON SNOWFALL THROUGH ABOUT
18Z SATURDAY BUT THEN EXPLODE SNOW AMOUNTS FOR SATURDAY NIGHT AND
SUNDAY. AMOUNTS FOR FRIDAY NIGHT ARE REASONABLE WITH BELOW ADVISORY
AMOUNTS. UNUSUALLY HIGH AMOUNTS FOR SATURDAY NIGHT ARE IN QUESTION
WITH THE GFS DOUBLING SNOWFALL IN SIX HOURS FROM 8 INCHES TO 15
INCHES OVER SOUTHWEST PORTIONS OF EASTERN COLORADO. A LEAD SHORTWAVE
WILL PROVIDE FORCING FOR LIGHT RAIN MIXING WITH SNOW SATURDAY
EVENING OVER MAINLY EASTERN COLORADO AND THEN CHANGING TO SNOW
OVERNIGHT. HOWEVER, NAM FORECAST SOUNDINGS INDICATE WARM ENOUGH
TEMPERATURES TO KEEP PRECIPITATION AS RAIN EAST OF THE COLORADO
BORDER. THIS SEEMS PLAUSIBLE SINCE THE NAM AND GFS DO NOT BRING THE
COLD FRONT INTO THE FA UNTIL LATE SATURDAY AFTERNOON/EARLY SATURDAY
EVENING. LACK OF SHORTWAVE ENERGY/FORCING WILL LIMIT KEEP
ACCUMULATIONS SATURDAY TO VERY LIGHT IF ANY ACCUMULATION. FOR
SATURDAY NIGHT, FORCING PROVIDED BY THE COLD FRONT AND THE NEXT
SHORTWAVE WILL BRING THE NEXT ACCUMULATING SNOWFALL. THIS WILL BE
THE MOSTLY LIKELY TIMEFRAME WHEN A WINTER HIGHLIGHT MAY BE NEEDED
OVER EASTERN COLORADO AND THE FIRST TIER OF COUNTIES IN NORTHWEST
KS. UNDOUBTEDLY THE GREATEST SNOWFALL WILL BE OVER EASTERN COLORADO
WHERE THE MAIN DYNAMICS ARE PRESENT. A NORTH WIND AT 15 TO 25 MPH
WILL PRODUCE SOME AREAS OF BLOWING SNOW, ESPECIALLY SATURDAY NIGHT
BUT NOT ENOUGH TO PRODUCE BLIZZARD CONDITIONS. WIND CHILL READINGS
WILL FALL TO AROUND ZERO SATURDAY NIGHT AND SUNDAY MORNING.
MIN TEMPERATURES FRIDAY NIGHT SHOULD COOL TO THE MID 20S FRIDAY
NIGHT AND THE TEENS SATURDAY NIGHT. MAX TEMPERATURES SATURDAY
SHOULD RANGE FROM THE LOWER TO MID 30S AND THEN AROUND 20 SUNDAY.
IN THE EXTENDED...(SUNDAY NIGHT THROUGH THURSDAY)...THE SPLIT UPPER
TROUGH CONTINUES SUNDAY NIGHT THROUGH TUESDAY WITH NORTHWEST FLOW
FOLLOWING WEDNESDAY/THURSDAY. SURFACE HIGH PRESSURE WILL CONTINUE
OVER THE REGION THROUGH TUESDAY FOLLOWED BY A WEAK TROUGH WEDNESDAY.
SURFACE HIGH PRESSURE WILL MOVE INTO THE PLAINS BEHIND A COLD FRONT
THURSDAY.
SNOW CHANCES WILL DECREASE FROM CHANCE POPS SUNDAY NIGHT AND MONDAY
WITH LIGHT SNOW/FLURRIES ENDING. DRY WEATHER WILL RETURN TUESDAY
AND WEDNESDAY. THE NEXT CHANCE FOR LIGHT SNOW WILL BEGIN WEDNESDAY
EVENING AND CONTINUE THROUGH THURSDAY AS THE NEXT DISTURBANCE MOVES
INTO THE PLAINS.
MIN TEMPERATURES WILL START OUT IN THE SINGLE DIGITS ABOVE ZERO
SUNDAY NIGHT AND THEN MODERATE TO THE TEENS MONDAY NIGHT. MIN
TEMPERATURES WILL COOL BACK DOWN FROM THE LOWER 20S TUESDAY NIGHT TO
THE TEENS WEDNESDAY NIGHT.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 442 PM MST THU FEB 19 2015
VFR CONDITIONS TO DOMINATE NEXT 24 HOURS. CLEAR SKIES GIVE WAY TO
CIRRUS TONIGHT...FURTHER CLOUDED BY MID-LEVEL CLOUDS TOMORROW
MORNING. TOMORROW AFTERNOON...STRONG SHORTWAVE TROUGH...CURRENTLY
LOCATED OVER THE PACIFIC NORTHWEST...ENCROACHES. PRECIP DEVELOPS
OVER NORTH CENTRAL COLORADO AND HEADS EAST BUT SHOULD NOT IMPACT
SITES BEFORE 00Z. COMPLICATED SURFACE WIND FORECAST THIS RUN AS A
LEE TROUGH PASSES TONIGHT AND A SURFACE LOW DEEPENS TOMORROW.
OVERALL...WINDS VEER FROM SOUTH TO NORTHWEST TONIGHT...THEN
NORTHEAST TOMORROW AS SURFACE LOW DEVELOPS. NEED TO MONITOR LOW
LEVEL WIND SHEAR THIS EVENING. RAP GUIDANCE INDICATES A LLJ THIS
EVENING AND WITH LIGHT SURFACE WINDS...LLWS CRITERIA MAY BE MET.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...WINTER STORM WATCH FROM SATURDAY AFTERNOON THROUGH SUNDAY
EVENING FOR COZ090>092.
NE...NONE.
&&
$$
UPDATE...RRH
SHORT TERM...MK
LONG TERM...FS
AVIATION...RRH
AREA FORECAST DISCUSSION
NWS GOODLAND KS
442 PM MST THU FEB 19 2015
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 217 PM MST THU FEB 19 2015
WATER VAPOR IMAGERY INDICATED A PLUME OF MOISTURE MOVING BETWEEN THE
LARGE UPPER LEVEL TROUGH OVER THE NORTHEAST AND THE UPPER LEVEL
RIDGE POSITIONED OVER MEXICO. THIS MOISTURE WAS BRINGING SOME DENSE
UPPER LEVEL CLOUDS FOR PORTIONS OF CENTRAL AND SOUTHWEST NEBRASKA.
ELSEWHERE...CLOUD COVER WAS MOSTLY CLEAR.
A STEADY STREAM OF WATER VAPOR MOISTURE WILL CONTINUE TO STREAM
BETWEEN THE UPPER LEVEL TROUGH OVER THE NORTHEAST AND THE UPPER
RIDGE OVER MEXICO...WHICH WILL BRING CLOUD COVER FOR NORTH CENTRAL
KANSAS AND SOUTH CENTRAL NEBRASKA LATE THIS AFTERNOON. CLOUD COVER
WILL DISSIPATE THIS EVENING AS DRY AIR SETTLES INTO THE REGION.
ALTHOUGH CLOUD COVER TONIGHT WILL BE LACKING...SOUTHERLY WINDS WILL
KEEP LOW TEMPERATURES WARMER IN THE MID TO UPPER 20S.
FRIDAY WILL BE ANOTHER WARMER THAN AVERAGE DAY IN THE LOW TO MID 50S
AHEAD OF A COLD SURGE OF AIR ASSOCIATED WITH THE NEXT WINTER STORM
TO AFFECT THE TRI STATE AREA. A POCKET OF POTENTIAL VORTICITY AHEAD
OF AN UPPER LEVEL TROUGH SLIDING DOWN THE FRONT RANGE OF THE ROCKIES
WILL BRING INCREASED CLOUD COVER FOR LOCATIONS NORTH OF INTERSTATE
70 BY THE EARLY AFTERNOON. OVERCAST CONDITIONS WILL BE ACROSS THE
ENTIRE FORECAST AREA BY LATE AFTERNOON WITH SOME PRECIPITATION
BEGINNING TO MOVE INTO EASTERN COLORADO AND SOUTHWEST NEBRASKA. WITH
850 TEMPS ABOVE FREEZING...CRITICAL 850-700 MB THICKNESSES ABOVE
1540 METERS AND SURFACE TEMPERATURES ABOVE FREEZING...EXPECTING
PRECIPITATION TO START AS RAIN. RAIN WILL BEGIN TO TRANSITION TO A
RAIN SNOW MIX LATER INTO THE EVENING HOURS.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 217 PM MST THU FEB 19 2015
A LARGE UPPER TROUGH WILL PUSH SOUTH INTO THE MID SECTION OF THE
CONUS FRIDAY NIGHT AND SATURDAY AND THEN START SPLITTING SUNDAY.
THE ENERGY IS ADVERTISED TO SPLIT TOWARDS NORTHERN CALIFORNIA AND
THE GREAT LAKES WITH SOME RIDGING OVER THE CENTRAL PLAINS. A
SURFACE TROUGH WILL EXIST OVER THE CENTRAL AND NORTHERN PLAINS
FRIDAY NIGHT AND THEN SHIFT EAST SATURDAY. SURFACE HIGH PRESSURE
WILL MOVE INTO THE CENTRAL PLAINS BEHIND THE EXITING TROUGH WITH A
COLD FRONT ENTERING NORTHWEST KANSAS AS EARLY AS LATE SATURDAY
AFTERNOON.
PLAN TO ISSUE A WINTER STORM WATCH FOR EASTERN COLORADO FROM
SATURDAY EVENING THROUGH SUNDAY NIGHT FOR THE HIGHER SNOW AMOUNTS
OVER THOSE COUNTIES. (SEE DETAILS BELOW)
THE GFS AND NAM ARE IN DECENT AGREEMENT ON SNOWFALL THROUGH ABOUT
18Z SATURDAY BUT THEN EXPLODE SNOW AMOUNTS FOR SATURDAY NIGHT AND
SUNDAY. AMOUNTS FOR FRIDAY NIGHT ARE REASONABLE WITH BELOW ADVISORY
AMOUNTS. UNUSUALLY HIGH AMOUNTS FOR SATURDAY NIGHT ARE IN QUESTION
WITH THE GFS DOUBLING SNOWFALL IN SIX HOURS FROM 8 INCHES TO 15
INCHES OVER SOUTHWEST PORTIONS OF EASTERN COLORADO. A LEAD SHORTWAVE
WILL PROVIDE FORCING FOR LIGHT RAIN MIXING WITH SNOW SATURDAY
EVENING OVER MAINLY EASTERN COLORADO AND THEN CHANGING TO SNOW
OVERNIGHT. HOWEVER, NAM FORECAST SOUNDINGS INDICATE WARM ENOUGH
TEMPERATURES TO KEEP PRECIPITATION AS RAIN EAST OF THE COLORADO
BORDER. THIS SEEMS PLAUSIBLE SINCE THE NAM AND GFS DO NOT BRING THE
COLD FRONT INTO THE FA UNTIL LATE SATURDAY AFTERNOON/EARLY SATURDAY
EVENING. LACK OF SHORTWAVE ENERGY/FORCING WILL LIMIT KEEP
ACCUMULATIONS SATURDAY TO VERY LIGHT IF ANY ACCUMULATION. FOR
SATURDAY NIGHT, FORCING PROVIDED BY THE COLD FRONT AND THE NEXT
SHORTWAVE WILL BRING THE NEXT ACCUMULATING SNOWFALL. THIS WILL BE
THE MOSTLY LIKELY TIMEFRAME WHEN A WINTER HIGHLIGHT MAY BE NEEDED
OVER EASTERN COLORADO AND THE FIRST TIER OF COUNTIES IN NORTHWEST
KS. UNDOUBTEDLY THE GREATEST SNOWFALL WILL BE OVER EASTERN COLORADO
WHERE THE MAIN DYNAMICS ARE PRESENT. A NORTH WIND AT 15 TO 25 MPH
WILL PRODUCE SOME AREAS OF BLOWING SNOW, ESPECIALLY SATURDAY NIGHT
BUT NOT ENOUGH TO PRODUCE BLIZZARD CONDITIONS. WIND CHILL READINGS
WILL FALL TO AROUND ZERO SATURDAY NIGHT AND SUNDAY MORNING.
MIN TEMPERATURES FRIDAY NIGHT SHOULD COOL TO THE MID 20S FRIDAY
NIGHT AND THE TEENS SATURDAY NIGHT. MAX TEMPERATURES SATURDAY
SHOULD RANGE FROM THE LOWER TO MID 30S AND THEN AROUND 20 SUNDAY.
IN THE EXTENDED...(SUNDAY NIGHT THROUGH THURSDAY)...THE SPLIT UPPER
TROUGH CONTINUES SUNDAY NIGHT THROUGH TUESDAY WITH NORTHWEST FLOW
FOLLOWING WEDNESDAY/THURSDAY. SURFACE HIGH PRESSURE WILL CONTINUE
OVER THE REGION THROUGH TUESDAY FOLLOWED BY A WEAK TROUGH WEDNESDAY.
SURFACE HIGH PRESSURE WILL MOVE INTO THE PLAINS BEHIND A COLD FRONT
THURSDAY.
SNOW CHANCES WILL DECREASE FROM CHANCE POPS SUNDAY NIGHT AND MONDAY
WITH LIGHT SNOW/FLURRIES ENDING. DRY WEATHER WILL RETURN TUESDAY
AND WEDNESDAY. THE NEXT CHANCE FOR LIGHT SNOW WILL BEGIN WEDNESDAY
EVENING AND CONTINUE THROUGH THURSDAY AS THE NEXT DISTURBANCE MOVES
INTO THE PLAINS.
MIN TEMPERATURES WILL START OUT IN THE SINGLE DIGITS ABOVE ZERO
SUNDAY NIGHT AND THEN MODERATE TO THE TEENS MONDAY NIGHT. MIN
TEMPERATURES WILL COOL BACK DOWN FROM THE LOWER 20S TUESDAY NIGHT TO
THE TEENS WEDNESDAY NIGHT.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 442 PM MST THU FEB 19 2015
VFR CONDITIONS TO DOMINATE NEXT 24 HOURS. CLEAR SKIES GIVE WAY TO
CIRRUS TONIGHT...FURTHER CLOUDED BY MID-LEVEL CLOUDS TOMORROW
MORNING. TOMORROW AFTERNOON...STRONG SHORTWAVE TROUGH...CURRENTLY
LOCATED OVER THE PACIFIC NORTHWEST...ENCROACHES. PRECIP DEVELOPS
OVER NORTH CENTRAL COLORADO AND HEADS EAST BUT SHOULD NOT IMPACT
SITES BEFORE 00Z. COMPLICATED SURFACE WIND FORECAST THIS RUN AS A
LEE TROUGH PASSES TONIGHT AND A SURFACE LOW DEEPENS TOMORROW.
OVERALL...WINDS VEER FROM SOUTH TO NORTHWEST TONIGHT...THEN
NORTHEAST TOMORROW AS SURFACE LOW DEVELOPS. NEED TO MONITOR LOW
LEVEL WIND SHEAR THIS EVENING. RAP GUIDANCE INDICATES A LLJ THIS
EVENING AND WITH LIGHT SURFACE WINDS...LLWS CRITERIA MAY BE MET.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...WINTER STORM WATCH FROM SATURDAY AFTERNOON THROUGH SUNDAY
EVENING FOR COZ090>092.
NE...NONE.
&&
$$
SHORT TERM...MK
LONG TERM...FS
AVIATION...RRH
AREA FORECAST DISCUSSION
NWS PADUCAH KY
543 PM CST THU FEB 19 2015
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 247 PM CST THU FEB 19 2015
...TONIGHT THROUGH FRIDAY...
RADAR/OBS NETWORK SHOWS SOME 20DBZ PLUS ECHOES IN WESTERN MO
PRODUCING LIGHT SNOW AT TIMES. THE RUN TO RUN MODEL TRENDS HAVE BEEN
CONSISTENTLY BRINGING THIS PCPN INTO SEMO OVERNIGHT...IMPACTING SEMO
AND NEARBY SWIL/FAR SWKY. WITH THE LOWER 3K FEET REMAINING QUITE
DRY...THE END RESULT IS AN ADJUSTED SNOW ACCUMULATION FORECAST GRID
TOTAL TONITE OF NOT MORE THAN ABOUT A HALF INCH OR SO FOR THAT
AREA...BASED ON LIQUID QPF OF 2-3 HUNDREDTHS OF AN INCH.
ON TO FRIDAY...WARMING ALOFT IS NOTED...AND THE SOUNDINGS LIKEWISE
SHOW DRYING IN THE -10C TO -20C LAYER AS THIS OCCURS. THE WARM NOSE
GROWS ABOUT 4K FEET THICK IN THE APPROX 3K-7K FEET ALOFT LAYER (AT
ITS PEAK)...AND THE END RESULT IS A TRANSITION FROM SNOW TO SLEET
FOR ALL AS THE DAY WEARS ON. LIQUID QPF YIELDS COMBO SNOW/ICE TOTALS
IN MAINLY THE SOUTH/WEST HALF OF ABOUT 1/2 INCH TO 3/4 INCH SWATH
AVERAGE AMOUNTS ACROSS FAR SEMO/SOUTHERN-MOST SOUTHWEST KY DURING
THIS TIME FRAME. FURTHER NORTH/EAST...IT APPEARS TO BE STILL TOO
COLD/KEPT ALL SNOW MENTION...THOUGH WE ACKNOWLEDGE THIS STARTS TO
CHANGE CLOSE TO 00Z SATURDAY (AROUND 22-23Z FRIDAY) AS YOU MOVE
EAST OF THE LAKES.
...FRIDAY NIGHT THROUGH SUNDAY...
THE 12Z GFS AND ECMWF ARE IN VERY GOOD AGREEMENT IN THE
LOCATION/PATH OF THE SURFACE LOW/TROUGH FRIDAY NIGHT THROUGH
SATURDAY. THIS FORECAST CLOSELY FOLLOWS A BLEND OF THESE TWO
MODELS.
THERE ARE A FEW NOTABLE CHANGES FROM YESTERDAY. THE ELEVATED
INSTABILITY IN THE GFS IS SOUTH OF THE REGION...BUT THE ECMWF
STILL HAS SOME IN THE SOUTHERN THIRD OF THE AREA LATE FRIDAY NIGHT
AND SATURDAY. SPC`S DAY 2 STILL HAS THAT AREA IN GENERAL
THUNDER...SO KEPT A MENTION.
THE GFS IS WETTER THAN THE ECMWF...BUT THE HEAVIEST RAINS ARE
TRENDING SOUTHEAST. WITH THIS TREND IN MIND AND ALL OF THE WINTER
QUESTIONS IN THE MEANTIME...WILL NOT BE ISSUING ANY FLOOD RELATED
PRODUCTS WITH THIS FORECAST PACKAGE. WE WILL CONTINUE TO MENTION
THE CONCERN IN THE HWO.
AS FOR THE WINTER MESS. DECIDED TO GO WITH A WINTER STORM WATCH
FOR THE ENTIRE AREA FROM 18Z FRIDAY TO 12Z SATURDAY. STILL HAVING
A HARD TIME COMING UP WITH SIGNIFICANT SNOW/SLEET OR ICE
ACCUMULATIONS...BUT WE WILL SEE SOME OF ALL THREE PRECIPITATION
TYPES...AND THE POTENTIAL IS THERE FOR SOME AREAS TO REACH WARNING
CRITERIA FOR THE COMBINATION OF ICE AND SNOW/SLEET.
WE ARE STILL VERY CONCERNED ABOUT THE ICING POTENTIAL FRIDAY
NIGHT...BUT THE ECMWF AND GFS CONTINUE TO BE VERY AGGRESSIVE IN
WARMING TEMPERATURES ABOVE FREEZING OVER THE ENTIRE AREA BY 12Z
SATURDAY. FIGURE THAT ANY ICING ISSUES WILL BE SHORT-LIVED IN THIS
SCENARIO. HOWEVER...WE WILL CONTINUE TO MONITOR FUTURE RUNS FOR A
SHIFT IN THE PATH OF THE SURFACE LOW.
THE 12Z NAM WAS QUITE COLD AND CERTAINLY IS NOT UNBELIEVABLE. IT
IS AN OUTLIER AT THIS TIME...SO WILL CONSIDER IT TO BE THE COLD
END OF THE RANGE OF POSSIBILITIES...BUT WILL STAY WITH THE
MAJORITY OF GUIDANCE WHICH IS MORE IN LINE WITH THE EXISTING
FORECAST.
THE 12Z MODELS ARE IN AGREEMENT IN PUSHING THE PRECIPITATION
MOSTLY EAST OF THE AREA BY 06Z SUNDAY...SO THERE IS NOT MUCH TIME
FOR A CHANGE OVER TO SNOW OR FREEZING RAIN BEFORE THE
PRECIPITATION COMES TO AN END. WILL MENTION THE CHANGE OVER...BUT
WITH LITTLE OR NO ICE/SNOW ACCUMULATION.
AS FOR TEMPERATURES...TRENDED DOWNWARD A BIT FOR SATURDAY...BUT
STILL ABOVE FREEZING. ALSO TRENDED DOWNWARD FOR SATURDAY NIGHT AND
SUNDAY...AS ANOTHER MAJOR SURFACE HIGH SETTLES OVER THE REGION.
.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 247 PM CST THU FEB 19 2015
THIS TIME FRAME IS LARGELY DESCRIBED AS A DRY/COLD PORTION OF THE
FORECAST. WE`LL BE ON THE BACKSIDE OF THE DEPARTING SYSTEM SUNDAY
WITH ITS REINFORCED ARCTIC AIR FUNNELING IN...CREATING SUNDAY HIGHS
IN THE 20S NORTH...TAPERING TO LOWER 30S SOUTH/EAST. THE ARCTIC AIR
COMES IN FULL FORCE ON AS A 1040-45MB SURFACE HIGH BUILDS ACROSS THE
OHIO VALLEY. RESULTANT LOWS WILL FALL INTO THE SINGLE DIGITS/EVEN
NEAR ZERO NORTH...AND LOWER TEENS SOUTH...SUNDAY NIGHT.
CORRESPONDING NEXT DAY LOWS UNDER SAME HIGH PRESSURE SYSTEM RANGE
FROM TEENS NORTH TO 20S SOUTH.
THE HIGH MOVES EAST BY MID WEEK AND WE START TO MODERATE BEFORE THE
NEXT REINFORCING COLD SHOT. IT STILL LOOKS DRY...BUT PCPN CHANCES DO
EXIST JUST BEYOND THE FA...AND MAY END UP YIELDING A SMALL CHANCE
MENTION HERE OR THERE BEFORE ALL IS SAID AND DONE. STILL
LARGELY...THE DRY FORECAST SHOULD HOLD...AS WELL AS COLD...EVEN WITH
MODERATION...WITH TUE-WED HIGHS IN THE 30S AND LOWS IN THE TEENS.
LONGER RANGE INDICATORS SUGGEST A REINFORCED SHOT OF COLD TOWARD THE
END OF THE WEEK...WITH HIGHS BACK IN THE 20S AND LOWS IN THE SINGLE
DIGITS BY DAY 7 (OR 8).
&&
.AVIATION...
ISSUED AT 543 PM CST THU FEB 19 2015
THE 3KM HRRR MODEL GUIDANCE IS INITIALIZING A LITTLE FURTHER
SOUTHWEST THAN THE 0.5 DEGREE NWS RADAR MOSAIC REFLECTIVITY FOR
SNOW THIS AFTERNOON OVER MISSOURI. WILL BE WATCHING THE 18-25DBZ
BANDS FOR SATURATING THE MID-DECK FOR SNOW REACHING THE SURFACE.
AT THIS POINT, WILL WATCH THE EVOLUTION OF THE EASTWARD MOVING
SNOW BANDS FOR THE NEED TO ACCELERATE THE ONSET OF LOWER VFR
CEILINGS, ESPECIALLY AT KCGI/KPAH. OTHERWISE, DO NOT PLAN TO
INTRODUCE MVFR CEILINGS UNTIL AFTER 12Z, WITH THE ONSET OF SNOW
WITHIN 2-3 HOURS AFTER THE BEGINNING OF THE MVFR CEILINGS.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...WINTER STORM WATCH FROM FRIDAY AFTERNOON THROUGH LATE FRIDAY
NIGHT FOR ILZ075>078-080>094.
MO...WINTER STORM WATCH FROM FRIDAY AFTERNOON THROUGH LATE FRIDAY
NIGHT FOR MOZ076-086-087-100-107>112-114.
IN...WINTER STORM WATCH FROM FRIDAY AFTERNOON THROUGH LATE FRIDAY
NIGHT FOR INZ081-082-085>088.
KY...WINTER STORM WATCH FROM FRIDAY AFTERNOON THROUGH LATE FRIDAY
NIGHT FOR KYZ001>022.
&&
$$
SHORT TERM...DRS/DH
LONG TERM...DH
AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
208 PM EST Wed Feb 18 2015
...Forecast Update...
Issued at 208 PM EST Wed Feb 18 2015
Just did a quick update to upgrade the Wind Chill Advisory to a Wind
Chill Warning for late this afternoon and tonight. Based on the
latest forecast data, overnight wind chill readings are likely to
drop into the -25 to -30 degree range. Updated Winter Weather
Bulletins are out.
Remainder of the forecast remains on track. Plenty of NW to SE
moving bands of snow showers and squalls continue to move across the
region. We expect this activity to continue through sunset then
rapidly diminish. Temperatures remain in the low teens but will
drop into the single digits late this afternoon and evening.
Update issued at 1045 AM EST Wed Feb 18 2015
NW-SE oriented snow squalls continue to move through central and
east-central KY this morning. These squalls are moving off to the
east at 25-30 MPH and will affect the Bluegrass region of central KY
for the remainder of the morning.
Latest runs from the HRRR suggest that more NW-SE oriented finger
bands of snow squalls are expected to redevelop across the region.
Based on the last few runs of the HRRR, it appears that the best
coverage of snow showers/squalls would generally be along and east
of the I-65 corridor. Based on those trends, have increased PoPs and
cloud cover east of I-65 for the afternoon hours. While we will be
running high chance PoPs, it really is more based on expected
coverage. Some areas will see snow showers, others may escape with
only flurries. Within these squalls an additional 1 to perhaps as
much as 2 inches could be seen...especially if a band sets up over a
particular area.
We will keep the Winter Weather Advisory going through the afternoon
for the entire area. Temperatures will continue to fall with
readings mainly in the teens with a fall into single digits by the
evening. With the loss of heating and the trough axis aloft heading
to the east, we expect to see the snow shower/squall activity drop
off rapidly after sunset.
Based on upstream observations, it appears we will go more clear
tonight resulting in temperatures falling well below zero
overnight. Current thinking is that our current forecast minimums
are too warm and that further downward adjustments will be needed.
We will continue to look at the full 12Z guidance before making
major adjustments. In addition, current wind forecasts combined
with colder temperatures may necessitate an upgrade of the wind
chill advisory to a wind chill warning. Will be collaborating with
surrounding offices on this during the afternoon.
Update issued at 938 AM EST Wed Feb 18 2015
Pretty decent snow squall moving eastward through the central part
of the forecast area. The squall is just west of US 27/127 and will
continue to move east at 25-30 MPH. The squall is producing heavy
snow, winds up to 25-30 MPH and reducing visibilities down below 1/4
of a mile. This will impact the Frankfort and Lexington areas in
the next hour. One half to one inch of snowfall is expected with
this squall. Although, it is very difficult to measure the exact
snowfall as the 25-30 MPH winds are really whipping the snow around.
Update issued at 819 AM EST Wed Feb 18 2015
Surface cold front is currently pushing through the I-65 corridor at
the moment and will continue eastward toward the I-75 corridor this
morning. Current tracking suggests that it will clear our forecast
area by 16-17Z. A few snow showers will trail behind the cold
front, but the bulk of snow will still occur out ahead of the front.
Northwest winds of 15-20 MPH with gusts up to 25 MPH will be common
as we continue into the morning hours. We will see a brief lull in
the snow shower activity, but we expect snow showers and heavier
snow squalls to redevelop this afternoon. These squalls will have
the potential to lay down some additional localized accumulations.
Temperatures will continue to fall through the afternoon, so the
warmest temperatures of the day have already occurred.
.SHORT TERM (Now through Thursday)...
Issued at 318 AM EST Wed Feb 18 2015
...Bitter cold temperatures and wind chills...
An area of light to moderate snow will cross the region early this
morning, exiting to the east by late morning. Accumulations around
an inch to as much as 2 inches still look reasonable, so will keep
the Winter Weather Advisory going.
A cold front crossing the area early this morning will usher in
gusty west winds and very cold air. Winds of 10 to 20 mph will gust
to 20 to 30 mph. The CAA behind the front will cause temperatures
to fall this afternoon. The combination of very cold temperatures
and brisk winds will lead to wind chills at or below -10 by mid
afternoon, so will hoist a Wind Chill Advisory.
This afternoon we`ll have strong cold air advection aloft and partly
to mostly cloudy skies, leading to weak instability. We`ll have
high RH below 700 hPa, much of it in temperatures very conducive to
snowflake growth. Also, we`ll be beneath upper level cyclonic flow
and SPC`s snow squall parameter is expected to be around 3, which is
very supportive of snow showers. As a result, scattered snow
showers are expected throughout the area this afternoon, and could
put down additional local accumulations. In addition to the snow
showers, those biting winds on top of the new fluffy snow from this
morning (plus the pre-existing snow pack from Monday) will lead to
blowing snow, especially in rural areas. As a result, will keep the
Winter Weather Advisory going through the afternoon for the
combination of falling snow, blowing snow, and dangerous wind chills.
Any snow showers this afternoon should end quickly this evening as
the sun sets and the upper trof axis is well east of here.
With the deep snowpack in place, reinforced by new snow this morning
and possibly this afternoon, temperatures tonight will be extremely
cold. Kept the forecast we`ve had going for the past few days, and,
after seeing some of the amazing numbers on the Kentucky Mesonet for
yesterday morning`s lows, ran a tool we have that takes local cold
spots into account when determining the low temperature forecast.
The tool gave lows as low as -20 in a few locations for Thursday
morning. Decided to temper the numbers just a bit, keeping them in
the -9 to -17 range (there may be scattered clouds in the area, plus
some wind), but suffice to say that it will be a cold night. Winds
near 10 mph will continue to give us extremely cold wind chills,
possibly meeting warning criteria. If widespread warning criteria
look likely, the Wind Chill Advisory may need to be upgraded.
Tomorrow the arctic high that is giving us all this cold air will
move right into the Ohio Valley. For now we will aim for highs in
the single digits, though some locations...especially those in the
Blue Grass that have the deepest snow cover...may be lucky to get
above zero. West winds of 10 to 15 mph will continue to provide
advisory level wind chills...possibly warning level in the morning.
For the past couple of days the GFS has been advertising slightly
deeper moisture than most other models Thursday afternoon, and has
been consistent in generating some extremely light QPF. As a nod to
the model`s insistence, will add in some scattered flurries Thursday
afternoon over the Blue Grass. It doesn`t take much to squeeze a
few snowflakes out of air this cold.
For now, will allow the Wind Chill Advisory to expire Thursday
evening since winds Thursday night go nearly calm. Nevertheless,
even a tiny breeze will result in very cold wind chills in this
frigid air. Future shifts will continue to assess if an advisory
will be needed for Thursday night into Friday.
Thanks to IND, JKL, and ILN for coord.
.LONG TERM (Thursday night through Tuesday)...
Issued at 300 AM EST Wed Feb 18 2015
...Record Cold Friday Morning Then Potential Weekend Wintry Mess...
Thursday night is shaping up to be the second consecutive night of
record cold for central Kentucky and southern Indiana as a very
anomalous Arctic airmass takes over the Ohio Valley. Synoptically,
the deep upper trough will be anchored over the Great Lakes and
Northeast US while the Arctic high advances from the central Plains
eastward, centering itself over eastern Kentucky by 12z Friday
morning. 850 mb temperatures are expected to be in the -22 to -25C
range, which would be a record for ILN upper air sounding
climatology. NAEFS standardized anomalies consistently show -4 to
-5SD from Wed 18z to Fri 18z, an impressive 48 hour stretch. Helping
to reach these extreme temperatures will be the recent snowpack and
lighter winds and overall mostly clear skies. However, high level
clouds are likely to spread east across the area after midnight,
which could limit the radiational cooling, especially west of I-65.
Overall though, confidence is high that we`ll see lows -10 to -15F
with isolated -20F readings not out of the question for the rural,
typical cold spots of central/eastern Kentucky. Given these extreme
low temperatures, although winds are expected to be less than 10
mph, even light winds will create dangerous wind chills of -20 to
-25 overnight into Friday morning.
Weekend Storm System:
A wintry mix mess is looking likely for much of the region beginning
Friday late afternoon through Saturday. The upper level pattern will
transition to zonal to slightly southwesterly as a western CONUS
trough digs. Pieces of energy will eject out into the southern
Plains resulting in a surface low developing across northern Texas
by Friday evening.
Increasing moist southerly flow ahead of the surface low and
increasing isentropic lift should lead to precipitation breaking out
across Tennessee and southern Kentucky as early as mid afternoon.
Thermal profiles suggest this would be all snow and could produce
quick minor accumulations Friday late afternoon, possibly during the
afternoon commute for areas along the KY/TN border.
During the evening hours, the surface low begins to intensify and
lift toward the region. Precipitation will increase and spread
northward. A low-level jet between 700 and 900 mb will bring a warm
nose of air northward during the evening hours, expected to reach
north central Kentucky by late evening or early overnight. Right now
soundings show this warm layer being on the order of +1 to +3C
during the overnight hours, then steadily increasing Saturday
morning. North of the KY parkways, precipitation could remain as
snow for several hours before mixing with sleet then going over to a
period of freezing rain early Saturday morning. After sunrise
Saturday, most of the area is expected to be near to slightly above
freezing. The exception is across southern Indiana where
temperatures may remain cold enough to support more of a wintry mix
during the morning hours Saturday.
Saturday afternoon through Saturday night the surface low tracks
through Kentucky and precipitation is expected to continue as mainly
rain as the low levels should be sufficiently warm. Precipitation
begins to exit late Saturday night or Sunday morning, which could be
a rain/snow to snow changeover as colder air wraps behind the
system.
Model Preferences / Trends:
A time-trend analysis has shown slight warming in the thermal
profiles over the last 4 cycles, though nothing too significant at
this point. Additionally, the models seem to be a bit more amplified
and slower compared to the past runs. It is noted that the GEM was a
fast outlier while the GFS was similarly on the slower side of the
spread. The forecast was weighted toward the 18.00z ECMWF which
seems to be a good compromise at this point given the large model
spread in timing. The 18.00z guidance as a whole trended back toward
a stronger surface system, which would likely bring warmer air
northward into the region. Overall, confidence in storm track and
timing is average.
Sensible Weather and Impacts:
Overall, a wintry mess is looking more likely across the area Friday
afternoon through Saturday afternoon. The initial snow could
accumulate around 2 inches across the area before changing over to a
wintry mix of sleet and freezing rain. We`ll have to watch for ice
accumulations across southern into central Kentucky where it could
total up to 0.1", causing additional impacts. If the low level
temperatures end up colder or climb slower than forecast, then there
would be a longer period of freezing rain. Something to watch. Then
finally we`ll deal with the liquid part of the event, which is
expected to be on the order of 0.5" or more. On top of a frozen
ground and new snow/sleet/freezing rain, this may cause some
localized hydrology issues for area creeks and streams.
Finally, despite surface temperatures warming above freezing
Saturday, road temperatures will be much slower to respond given the
recent cold snap this week. This could result in additional icy and
slick roadways, or at least further into the day Saturday.
Sunday - Tuesday:
In the wake of the weekend system, a reinforcing shot of Arctic air
is advertised by the 18.00z deterministic and ensemble guidance.
This supports a continuation of below normal temperatures with
northwest flow aloft. A model consensus of highs in the upper 20s to
mid 30s and overnight lows in the teens looks reasonable at this
time.
&&
.AVIATION (18Z TAF Update)...
Issued at 1208 PM EST Wed Feb 18 2015
Surface cold front has passed through the region and in its wake we
have numerous snow showers and snow squalls mainly out in central
Kentucky. Latest high resolution guidance suggests that more snow
showers and squalls will develop later this afternoon. Its
difficult to pinpoint if any particular squall would affect the
airports. For now plan on keeping light snow and blowing snow in at
KSDF and KLEX through the afternoon and snow showers within the
vicinity down at KBWG. Surface winds this afternoon will be out of
the northwest (290 deg mainly) with sustained speeds of 12-15kts
and gusts of around 24-27kts. The blowing snow may result in some
MVFR vsbys at times. Ceilings are generally expected to remain in
the MVFR range, but most likely will see it fluctuate between
MVFR/VFR.
After 19/00Z, we should see marked improvement at the terminals as
the snow shower activity ends. We expect mostly clear skies to
develop, though the models are trying to hold on to some low-level
moisture across the Bluegrass region overnight which may result in a
low cloud deck hanging around. Surface winds will remain elevated
this evening but are expected to slacken toward Thursday morning.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...WINTER WEATHER ADVISORY until 7 PM EST /6 PM CST/ this evening
FOR KYZ023>043-045>049-053>057-061>067-070>078-081-082.
WIND CHILL WARNING until Noon EST /11 AM CST/ Thursday FOR
KYZ023>043-045>049-053>057-061>067-070>078-081-082.
WIND CHILL ADVISORY from Noon EST /11 AM CST/ Thursday to 7 AM
EST /6 AM CST/ Friday FOR KYZ023>043-045>049-053>057-
061>067-070>078-081-082.
IN...WINTER WEATHER ADVISORY until 7 PM EST /6 PM CST/ this evening
FOR INZ076>079-083-084-089>092.
WIND CHILL WARNING until Noon EST /11 AM CST/ Thursday FOR
INZ076>079-083-084-089>092.
WIND CHILL ADVISORY from Noon EST /11 AM CST/ Thursday to 7 AM
EST /6 AM CST/ Friday FOR INZ076>079-083-084-089>092.
&&
$$
Update.........MJ
Short Term.....13
Long Term......ZBT
Aviation.......MJ
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1209 PM EST Wed Feb 18 2015
...Updated Aviation Discussion...
...Forecast Update...
Issued at 1045 AM EST Wed Feb 18 2015
NW-SE oriented snow squalls continue to move through central and
east-central KY this morning. These squalls are moving off to the
east at 25-30 MPH and will affect the Bluegrass region of central KY
for the remainder of the morning.
Latest runs from the HRRR suggest that more NW-SE oriented finger
bands of snow squalls are expected to redevelop across the region.
Based on the last few runs of the HRRR, it appears that the best
coverage of snow showers/squalls would generally be along and east
of the I-65 corridor. Based on those trends, have increased PoPs and
cloud cover east of I-65 for the afternoon hours. While we will be
running high chance PoPs, it really is more based on expected
coverage. Some areas will see snow showers, others may escape with
only flurries. Within these squalls an additional 1 to perhaps as
much as 2 inches could be seen...especially if a band sets up over a
particular area.
We will keep the Winter Weather Advisory going through the afternoon
for the entire area. Temperatures will continue to fall with
readings mainly in the teens with a fall into single digits by the
evening. With the loss of heating and the trough axis aloft heading
to the east, we expect to see the snow shower/squall activity drop
off rapidly after sunset.
Based on upstream observations, it appears we will go more clear
tonight resulting in temperatures falling well below zero
overnight. Current thinking is that our current forecast minimums
are too warm and that further downward adjustments will be needed.
We will continue to look at the full 12Z guidance before making
major adjustments. In addition, current wind forecasts combined
with colder temperatures may necessitate an upgrade of the wind
chill advisory to a wind chill warning. Will be collaborating with
surrounding offices on this during the afternoon.
Update issued at 938 AM EST Wed Feb 18 2015
Pretty decent snow squall moving eastward through the central part
of the forecast area. The squall is just west of US 27/127 and will
continue to move east at 25-30 MPH. The squall is producing heavy
snow, winds up to 25-30 MPH and reducing visibilities down below 1/4
of a mile. This will impact the Frankfort and Lexington areas in
the next hour. One half to one inch of snowfall is expected with
this squall. Although, it is very difficult to measure the exact
snowfall as the 25-30 MPH winds are really whipping the snow around.
Update issued at 819 AM EST Wed Feb 18 2015
Surface cold front is currently pushing through the I-65 corridor at
the moment and will continue eastward toward the I-75 corridor this
morning. Current tracking suggests that it will clear our forecast
area by 16-17Z. A few snow showers will trail behind the cold
front, but the bulk of snow will still occur out ahead of the front.
Northwest winds of 15-20 MPH with gusts up to 25 MPH will be common
as we continue into the morning hours. We will see a brief lull in
the snow shower activity, but we expect snow showers and heavier
snow squalls to redevelop this afternoon. These squalls will have
the potential to lay down some additional localized accumulations.
Temperatures will continue to fall through the afternoon, so the
warmest temperatures of the day have already occurred.
.SHORT TERM (Now through Thursday)...
Issued at 318 AM EST Wed Feb 18 2015
...Bitter cold temperatures and wind chills...
An area of light to moderate snow will cross the region early this
morning, exiting to the east by late morning. Accumulations around
an inch to as much as 2 inches still look reasonable, so will keep
the Winter Weather Advisory going.
A cold front crossing the area early this morning will usher in
gusty west winds and very cold air. Winds of 10 to 20 mph will gust
to 20 to 30 mph. The CAA behind the front will cause temperatures
to fall this afternoon. The combination of very cold temperatures
and brisk winds will lead to wind chills at or below -10 by mid
afternoon, so will hoist a Wind Chill Advisory.
This afternoon we`ll have strong cold air advection aloft and partly
to mostly cloudy skies, leading to weak instability. We`ll have
high RH below 700 hPa, much of it in temperatures very conducive to
snowflake growth. Also, we`ll be beneath upper level cyclonic flow
and SPC`s snow squall parameter is expected to be around 3, which is
very supportive of snow showers. As a result, scattered snow
showers are expected throughout the area this afternoon, and could
put down additional local accumulations. In addition to the snow
showers, those biting winds on top of the new fluffy snow from this
morning (plus the pre-existing snow pack from Monday) will lead to
blowing snow, especially in rural areas. As a result, will keep the
Winter Weather Advisory going through the afternoon for the
combination of falling snow, blowing snow, and dangerous wind chills.
Any snow showers this afternoon should end quickly this evening as
the sun sets and the upper trof axis is well east of here.
With the deep snowpack in place, reinforced by new snow this morning
and possibly this afternoon, temperatures tonight will be extremely
cold. Kept the forecast we`ve had going for the past few days, and,
after seeing some of the amazing numbers on the Kentucky Mesonet for
yesterday morning`s lows, ran a tool we have that takes local cold
spots into account when determining the low temperature forecast.
The tool gave lows as low as -20 in a few locations for Thursday
morning. Decided to temper the numbers just a bit, keeping them in
the -9 to -17 range (there may be scattered clouds in the area, plus
some wind), but suffice to say that it will be a cold night. Winds
near 10 mph will continue to give us extremely cold wind chills,
possibly meeting warning criteria. If widespread warning criteria
look likely, the Wind Chill Advisory may need to be upgraded.
Tomorrow the arctic high that is giving us all this cold air will
move right into the Ohio Valley. For now we will aim for highs in
the single digits, though some locations...especially those in the
Blue Grass that have the deepest snow cover...may be lucky to get
above zero. West winds of 10 to 15 mph will continue to provide
advisory level wind chills...possibly warning level in the morning.
For the past couple of days the GFS has been advertising slightly
deeper moisture than most other models Thursday afternoon, and has
been consistent in generating some extremely light QPF. As a nod to
the model`s insistence, will add in some scattered flurries Thursday
afternoon over the Blue Grass. It doesn`t take much to squeeze a
few snowflakes out of air this cold.
For now, will allow the Wind Chill Advisory to expire Thursday
evening since winds Thursday night go nearly calm. Nevertheless,
even a tiny breeze will result in very cold wind chills in this
frigid air. Future shifts will continue to assess if an advisory
will be needed for Thursday night into Friday.
Thanks to IND, JKL, and ILN for coord.
.LONG TERM (Thursday night through Tuesday)...
Issued at 300 AM EST Wed Feb 18 2015
...Record Cold Friday Morning Then Potential Weekend Wintry Mess...
Thursday night is shaping up to be the second consecutive night of
record cold for central Kentucky and southern Indiana as a very
anomalous Arctic airmass takes over the Ohio Valley. Synoptically,
the deep upper trough will be anchored over the Great Lakes and
Northeast US while the Arctic high advances from the central Plains
eastward, centering itself over eastern Kentucky by 12z Friday
morning. 850 mb temperatures are expected to be in the -22 to -25C
range, which would be a record for ILN upper air sounding
climatology. NAEFS standardized anomalies consistently show -4 to
-5SD from Wed 18z to Fri 18z, an impressive 48 hour stretch. Helping
to reach these extreme temperatures will be the recent snowpack and
lighter winds and overall mostly clear skies. However, high level
clouds are likely to spread east across the area after midnight,
which could limit the radiational cooling, especially west of I-65.
Overall though, confidence is high that we`ll see lows -10 to -15F
with isolated -20F readings not out of the question for the rural,
typical cold spots of central/eastern Kentucky. Given these extreme
low temperatures, although winds are expected to be less than 10
mph, even light winds will create dangerous wind chills of -20 to
-25 overnight into Friday morning.
Weekend Storm System:
A wintry mix mess is looking likely for much of the region beginning
Friday late afternoon through Saturday. The upper level pattern will
transition to zonal to slightly southwesterly as a western CONUS
trough digs. Pieces of energy will eject out into the southern
Plains resulting in a surface low developing across northern Texas
by Friday evening.
Increasing moist southerly flow ahead of the surface low and
increasing isentropic lift should lead to precipitation breaking out
across Tennessee and southern Kentucky as early as mid afternoon.
Thermal profiles suggest this would be all snow and could produce
quick minor accumulations Friday late afternoon, possibly during the
afternoon commute for areas along the KY/TN border.
During the evening hours, the surface low begins to intensify and
lift toward the region. Precipitation will increase and spread
northward. A low-level jet between 700 and 900 mb will bring a warm
nose of air northward during the evening hours, expected to reach
north central Kentucky by late evening or early overnight. Right now
soundings show this warm layer being on the order of +1 to +3C
during the overnight hours, then steadily increasing Saturday
morning. North of the KY parkways, precipitation could remain as
snow for several hours before mixing with sleet then going over to a
period of freezing rain early Saturday morning. After sunrise
Saturday, most of the area is expected to be near to slightly above
freezing. The exception is across southern Indiana where
temperatures may remain cold enough to support more of a wintry mix
during the morning hours Saturday.
Saturday afternoon through Saturday night the surface low tracks
through Kentucky and precipitation is expected to continue as mainly
rain as the low levels should be sufficiently warm. Precipitation
begins to exit late Saturday night or Sunday morning, which could be
a rain/snow to snow changeover as colder air wraps behind the
system.
Model Preferences / Trends:
A time-trend analysis has shown slight warming in the thermal
profiles over the last 4 cycles, though nothing too significant at
this point. Additionally, the models seem to be a bit more amplified
and slower compared to the past runs. It is noted that the GEM was a
fast outlier while the GFS was similarly on the slower side of the
spread. The forecast was weighted toward the 18.00z ECMWF which
seems to be a good compromise at this point given the large model
spread in timing. The 18.00z guidance as a whole trended back toward
a stronger surface system, which would likely bring warmer air
northward into the region. Overall, confidence in storm track and
timing is average.
Sensible Weather and Impacts:
Overall, a wintry mess is looking more likely across the area Friday
afternoon through Saturday afternoon. The initial snow could
accumulate around 2 inches across the area before changing over to a
wintry mix of sleet and freezing rain. We`ll have to watch for ice
accumulations across southern into central Kentucky where it could
total up to 0.1", causing additional impacts. If the low level
temperatures end up colder or climb slower than forecast, then there
would be a longer period of freezing rain. Something to watch. Then
finally we`ll deal with the liquid part of the event, which is
expected to be on the order of 0.5" or more. On top of a frozen
ground and new snow/sleet/freezing rain, this may cause some
localized hydrology issues for area creeks and streams.
Finally, despite surface temperatures warming above freezing
Saturday, road temperatures will be much slower to respond given the
recent cold snap this week. This could result in additional icy and
slick roadways, or at least further into the day Saturday.
Sunday - Tuesday:
In the wake of the weekend system, a reinforcing shot of Arctic air
is advertised by the 18.00z deterministic and ensemble guidance.
This supports a continuation of below normal temperatures with
northwest flow aloft. A model consensus of highs in the upper 20s to
mid 30s and overnight lows in the teens looks reasonable at this
time.
&&
.AVIATION (18Z TAF Update)...
Issued at 1208 PM EST Wed Feb 18 2015
Surface cold front has passed through the region and in its wake we
have numerous snow showers and snow squalls mainly out in central
Kentucky. Latest high resolution guidance suggests that more snow
showers and squalls will develop later this afternoon. Its
difficult to pinpoint if any particular squall would affect the
airports. For now plan on keeping light snow and blowing snow in at
KSDF and KLEX through the afternoon and snow showers within the
vicinity down at KBWG. Surface winds this afternoon will be out of
the northwest (290 deg mainly) with sustained speeds of 12-15kts
and gusts of around 24-27kts. The blowing snow may result in some
MVFR vsbys at times. Ceilings are generally expected to remain in
the MVFR range, but most likely will see it fluctuate between
MVFR/VFR.
After 19/00Z, we should see marked improvement at the terminals as
the snow shower activity ends. We expect mostly clear skies to
develop, though the models are trying to hold on to some low-level
moisture across the Bluegrass region overnight which may result in a
low cloud deck hanging around. Surface winds will remain elevated
this evening but are expected to slacken toward Thursday morning.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...WINTER WEATHER ADVISORY until 7 PM EST /6 PM CST/ this evening
FOR KYZ023>043-045>049-053>057-061>067-070>078-081-082.
WIND CHILL ADVISORY from 4 PM EST /3 PM CST/ this afternoon to 7
PM EST /6 PM CST/ Thursday FOR KYZ023>043-045>049-053>057-
061>067-070>078-081-082.
IN...WINTER WEATHER ADVISORY until 7 PM EST /6 PM CST/ this evening
FOR INZ076>079-083-084-089>092.
WIND CHILL ADVISORY from 4 PM EST /3 PM CST/ this afternoon to 7
PM EST /6 PM CST/ Thursday FOR INZ076>079-083-084-089>092.
&&
$$
Update.........MJ
Short Term.....13
Long Term......ZBT
Aviation.......MJ
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1046 AM EST Wed Feb 18 2015
...Forecast Update...
Issued at 1045 AM EST Wed Feb 18 2015
NW-SE oriented snow squalls continue to move through central and
east-central KY this morning. These squalls are moving off to the
east at 25-30 MPH and will affect the Bluegrass region of central KY
for the remainder of the morning.
Latest runs from the HRRR suggest that more NW-SE oriented finger
bands of snow squalls are expected to redevelop across the region.
Based on the last few runs of the HRRR, it appears that the best
coverage of snow showers/squalls would generally be along and east
of the I-65 corridor. Based on those trends, have increased PoPs and
cloud cover east of I-65 for the afternoon hours. While we will be
running high chance PoPs, it really is more based on expected
coverage. Some areas will see snow showers, others may escape with
only flurries. Within these squalls an additional 1 to perhaps as
much as 2 inches could be seen...especially if a band sets up over a
particular area.
We will keep the Winter Weather Advisory going through the afternoon
for the entire area. Temperatures will continue to fall with
readings mainly in the teens with a fall into single digits by the
evening. With the loss of heating and the trough axis aloft heading
to the east, we expect to see the snow shower/squall activity drop
off rapidly after sunset.
Based on upstream observations, it appears we will go more clear
tonight resulting in temperatures falling well below zero
overnight. Current thinking is that our current forecast minimums
are too warm and that further downward adjustments will be needed.
We will continue to look at the full 12Z guidance before making
major adjustments. In addition, current wind forecasts combined
with colder temperatures may necessitate an upgrade of the wind
chill advisory to a wind chill warning. Will be collaborating with
surrounding offices on this during the afternoon.
Update issued at 938 AM EST Wed Feb 18 2015
Pretty decent snow squall moving eastward through the central part
of the forecast area. The squall is just west of US 27/127 and will
continue to move east at 25-30 MPH. The squall is producing heavy
snow, winds up to 25-30 MPH and reducing visibilities down below 1/4
of a mile. This will impact the Frankfort and Lexington areas in
the next hour. One half to one inch of snowfall is expected with
this squall. Although, it is very difficult to measure the exact
snowfall as the 25-30 MPH winds are really whipping the snow around.
Update issued at 819 AM EST Wed Feb 18 2015
Surface cold front is currently pushing through the I-65 corridor at
the moment and will continue eastward toward the I-75 corridor this
morning. Current tracking suggests that it will clear our forecast
area by 16-17Z. A few snow showers will trail behind the cold
front, but the bulk of snow will still occur out ahead of the front.
Northwest winds of 15-20 MPH with gusts up to 25 MPH will be common
as we continue into the morning hours. We will see a brief lull in
the snow shower activity, but we expect snow showers and heavier
snow squalls to redevelop this afternoon. These squalls will have
the potential to lay down some additional localized accumulations.
Temperatures will continue to fall through the afternoon, so the
warmest temperatures of the day have already occurred.
.SHORT TERM (Now through Thursday)...
Issued at 318 AM EST Wed Feb 18 2015
...Bitter cold temperatures and wind chills...
An area of light to moderate snow will cross the region early this
morning, exiting to the east by late morning. Accumulations around
an inch to as much as 2 inches still look reasonable, so will keep
the Winter Weather Advisory going.
A cold front crossing the area early this morning will usher in
gusty west winds and very cold air. Winds of 10 to 20 mph will gust
to 20 to 30 mph. The CAA behind the front will cause temperatures
to fall this afternoon. The combination of very cold temperatures
and brisk winds will lead to wind chills at or below -10 by mid
afternoon, so will hoist a Wind Chill Advisory.
This afternoon we`ll have strong cold air advection aloft and partly
to mostly cloudy skies, leading to weak instability. We`ll have
high RH below 700 hPa, much of it in temperatures very conducive to
snowflake growth. Also, we`ll be beneath upper level cyclonic flow
and SPC`s snow squall parameter is expected to be around 3, which is
very supportive of snow showers. As a result, scattered snow
showers are expected throughout the area this afternoon, and could
put down additional local accumulations. In addition to the snow
showers, those biting winds on top of the new fluffy snow from this
morning (plus the pre-existing snow pack from Monday) will lead to
blowing snow, especially in rural areas. As a result, will keep the
Winter Weather Advisory going through the afternoon for the
combination of falling snow, blowing snow, and dangerous wind chills.
Any snow showers this afternoon should end quickly this evening as
the sun sets and the upper trof axis is well east of here.
With the deep snowpack in place, reinforced by new snow this morning
and possibly this afternoon, temperatures tonight will be extremely
cold. Kept the forecast we`ve had going for the past few days, and,
after seeing some of the amazing numbers on the Kentucky Mesonet for
yesterday morning`s lows, ran a tool we have that takes local cold
spots into account when determining the low temperature forecast.
The tool gave lows as low as -20 in a few locations for Thursday
morning. Decided to temper the numbers just a bit, keeping them in
the -9 to -17 range (there may be scattered clouds in the area, plus
some wind), but suffice to say that it will be a cold night. Winds
near 10 mph will continue to give us extremely cold wind chills,
possibly meeting warning criteria. If widespread warning criteria
look likely, the Wind Chill Advisory may need to be upgraded.
Tomorrow the arctic high that is giving us all this cold air will
move right into the Ohio Valley. For now we will aim for highs in
the single digits, though some locations...especially those in the
Blue Grass that have the deepest snow cover...may be lucky to get
above zero. West winds of 10 to 15 mph will continue to provide
advisory level wind chills...possibly warning level in the morning.
For the past couple of days the GFS has been advertising slightly
deeper moisture than most other models Thursday afternoon, and has
been consistent in generating some extremely light QPF. As a nod to
the model`s insistence, will add in some scattered flurries Thursday
afternoon over the Blue Grass. It doesn`t take much to squeeze a
few snowflakes out of air this cold.
For now, will allow the Wind Chill Advisory to expire Thursday
evening since winds Thursday night go nearly calm. Nevertheless,
even a tiny breeze will result in very cold wind chills in this
frigid air. Future shifts will continue to assess if an advisory
will be needed for Thursday night into Friday.
Thanks to IND, JKL, and ILN for coord.
.LONG TERM (Thursday night through Tuesday)...
Issued at 300 AM EST Wed Feb 18 2015
...Record Cold Friday Morning Then Potential Weekend Wintry Mess...
Thursday night is shaping up to be the second consecutive night of
record cold for central Kentucky and southern Indiana as a very
anomalous Arctic airmass takes over the Ohio Valley. Synoptically,
the deep upper trough will be anchored over the Great Lakes and
Northeast US while the Arctic high advances from the central Plains
eastward, centering itself over eastern Kentucky by 12z Friday
morning. 850 mb temperatures are expected to be in the -22 to -25C
range, which would be a record for ILN upper air sounding
climatology. NAEFS standardized anomalies consistently show -4 to
-5SD from Wed 18z to Fri 18z, an impressive 48 hour stretch. Helping
to reach these extreme temperatures will be the recent snowpack and
lighter winds and overall mostly clear skies. However, high level
clouds are likely to spread east across the area after midnight,
which could limit the radiational cooling, especially west of I-65.
Overall though, confidence is high that we`ll see lows -10 to -15F
with isolated -20F readings not out of the question for the rural,
typical cold spots of central/eastern Kentucky. Given these extreme
low temperatures, although winds are expected to be less than 10
mph, even light winds will create dangerous wind chills of -20 to
-25 overnight into Friday morning.
Weekend Storm System:
A wintry mix mess is looking likely for much of the region beginning
Friday late afternoon through Saturday. The upper level pattern will
transition to zonal to slightly southwesterly as a western CONUS
trough digs. Pieces of energy will eject out into the southern
Plains resulting in a surface low developing across northern Texas
by Friday evening.
Increasing moist southerly flow ahead of the surface low and
increasing isentropic lift should lead to precipitation breaking out
across Tennessee and southern Kentucky as early as mid afternoon.
Thermal profiles suggest this would be all snow and could produce
quick minor accumulations Friday late afternoon, possibly during the
afternoon commute for areas along the KY/TN border.
During the evening hours, the surface low begins to intensify and
lift toward the region. Precipitation will increase and spread
northward. A low-level jet between 700 and 900 mb will bring a warm
nose of air northward during the evening hours, expected to reach
north central Kentucky by late evening or early overnight. Right now
soundings show this warm layer being on the order of +1 to +3C
during the overnight hours, then steadily increasing Saturday
morning. North of the KY parkways, precipitation could remain as
snow for several hours before mixing with sleet then going over to a
period of freezing rain early Saturday morning. After sunrise
Saturday, most of the area is expected to be near to slightly above
freezing. The exception is across southern Indiana where
temperatures may remain cold enough to support more of a wintry mix
during the morning hours Saturday.
Saturday afternoon through Saturday night the surface low tracks
through Kentucky and precipitation is expected to continue as mainly
rain as the low levels should be sufficiently warm. Precipitation
begins to exit late Saturday night or Sunday morning, which could be
a rain/snow to snow changeover as colder air wraps behind the
system.
Model Preferences / Trends:
A time-trend analysis has shown slight warming in the thermal
profiles over the last 4 cycles, though nothing too significant at
this point. Additionally, the models seem to be a bit more amplified
and slower compared to the past runs. It is noted that the GEM was a
fast outlier while the GFS was similarly on the slower side of the
spread. The forecast was weighted toward the 18.00z ECMWF which
seems to be a good compromise at this point given the large model
spread in timing. The 18.00z guidance as a whole trended back toward
a stronger surface system, which would likely bring warmer air
northward into the region. Overall, confidence in storm track and
timing is average.
Sensible Weather and Impacts:
Overall, a wintry mess is looking more likely across the area Friday
afternoon through Saturday afternoon. The initial snow could
accumulate around 2 inches across the area before changing over to a
wintry mix of sleet and freezing rain. We`ll have to watch for ice
accumulations across southern into central Kentucky where it could
total up to 0.1", causing additional impacts. If the low level
temperatures end up colder or climb slower than forecast, then there
would be a longer period of freezing rain. Something to watch. Then
finally we`ll deal with the liquid part of the event, which is
expected to be on the order of 0.5" or more. On top of a frozen
ground and new snow/sleet/freezing rain, this may cause some
localized hydrology issues for area creeks and streams.
Finally, despite surface temperatures warming above freezing
Saturday, road temperatures will be much slower to respond given the
recent cold snap this week. This could result in additional icy and
slick roadways, or at least further into the day Saturday.
Sunday - Tuesday:
In the wake of the weekend system, a reinforcing shot of Arctic air
is advertised by the 18.00z deterministic and ensemble guidance.
This supports a continuation of below normal temperatures with
northwest flow aloft. A model consensus of highs in the upper 20s to
mid 30s and overnight lows in the teens looks reasonable at this
time.
&&
.AVIATION (12Z TAF Update)...
Issued at 630 AM EST Wed Feb 18 2015
An area of light to moderate snow will cross the terminals during
the first few hours of the TAF period. These snows will bring MVFR
ceilings and visibilities.
A cold front is crossing central Kentucky at the time of this
writing and will take winds from southwest to west, with gusts to
around 20 knots this morning. We should get a break from the snow
for a few hours during the mid to late morning hours.
This afternoon scattered snow showers will develop. The showers
should be spaced out enough to stick with VCSH in the TAFs for now.
More definitive cig/vsby can be ascertained closer to the time the
showers begin to form. Individual showers will reduce ceilings and
visibilities, but only briefly. West winds will continue, and will
gust to around 25 knots.
This evening skies will become partly cloudy and winds will relax
but continue to come in from the west as a long ridge of high
pressure builds into the Mississippi Valley.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...WINTER WEATHER ADVISORY until 7 PM EST /6 PM CST/ this evening
FOR KYZ023>043-045>049-053>057-061>067-070>078-081-082.
WIND CHILL ADVISORY from 4 PM EST /3 PM CST/ this afternoon to 7
PM EST /6 PM CST/ Thursday FOR KYZ023>043-045>049-053>057-
061>067-070>078-081-082.
IN...WINTER WEATHER ADVISORY until 7 PM EST /6 PM CST/ this evening
FOR INZ076>079-083-084-089>092.
WIND CHILL ADVISORY from 4 PM EST /3 PM CST/ this afternoon to 7
PM EST /6 PM CST/ Thursday FOR INZ076>079-083-084-089>092.
&&
$$
Update.........MJ
Short Term.....13
Long Term......ZBT
Aviation.......13
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
950 PM EST THU FEB 19 2015
.SYNOPSIS...
SCATTERED SNOW SHOWERS AND FLURRIES WILL END EARLY THIS EVENING AS
THE DRY ARCTIC AIR MASS CONTINUES TO POUR INTO THE REGION. DRY
WEATHER WILL CONTINUE ON FRIDAY BEFORE THE NEXT STORM SYSTEM
IMPACTS THE REGION ON SATURDAY.
&&
.NEAR TERM /THROUGH FRIDAY/...
WITH THE DENDRITIC GROWTH LAYER ON THE SURFACE AND CYCLONIC COLD
ADVECTING FLOW CONTINUING OVER THE GREAT LAKES...WIDESPREAD LONG
TRACK SNOW SHOWER BANDS CONTINUE DOWNWIND FROM THE OPEN WATERS OF
LAKES SUPERIOR...MICHIGAN...AND EVEN A PINCH OF LAKE HURON. LAKE
ERIE HAS BECOME ENTIRELY CUT OFF FROM UPWARD MOISTURE FLUX DUE TO
ICE COVER...AND GIVEN THE GREATLY INCREASING DEPTH...SIGNIFICANT
HEAT FLUX THROUGH THE ICE SEEMS UNLIKELY TO BE ENOUGH TO RADICALLY
CHANGE THE INSTABILITY REGIME OVER THE LAKE TO INDUCE INCREASED
SNOW BAND INTENSITY DOWNWIND OF IT. THAT SAID...BANDS FROM LAKE
MICHIGAN SEEM TO CONTINUE TO BE MAKING THEIR WAY ALL THE WAY
THROUGH EASTERN OHIO AND WESTERN PENNSYLVANIA FAIRLY EASILY EARLY
THIS EVENING...HOWEVER THAT IS LIKELY TO CHANGE RATHER DRASTICALLY
AS DIURNALLY INDUCED INSTABILITY WANES.
MODEL SOUNDINGS DO FAVOR ONE BAND SURVIVING IN SOME FORM OR
ANOTHER OFF THE SOUTH END OF LAKE MICHIGAN UNTIL THE LATE
EVENING...WITH MODEL RH FIELDS FROM THE NAM AND HRRR BOTH
INDICATING SOME BOUNDARY LAYER CONVERGENCE AND AN INCREASED RH
FIELD SAGGING SOUTHWARD FROM THE I-70 CORRIDOR THROUGH THE EVENING
HOURS. BEHIND THAT...DRIER BOUNDARY LAYER RH VALUES DO COME INTO
THE AREA...AND MODEL SOUNDINGS FAVOR WEAKER MIXING AND A FAR LESS
UNSTABLE ENVIRONMENT OVERNIGHT. ADDITIONALLY...A FAR WEAKER
SURFACE PRESSURE GRADIENT IS EVIDENT ON ALL GUIDANCE
OVERNIGHT...SO WHILE GUSTY NORTHWEST FLOW IS EVIDENT EARLY THIS
EVENING...THAT GRADIENT WILL WEAKEN RATHER SUBSTANTIALLY OUTSIDE
THE HIGHER ELEVATION AREAS OVERNIGHT. WHILE THIS WILL ALLOW FOR
THE WIND COMPONENT OF THE WIND CHILL TO RELAX...THE COMBINATION OF
LOWER RH VALUES AND SOME MODEST DECOUPLING OVER THE LOWER
ELEVATIONS WILL ALLOW FOR THE TEMPERATURE PORTION OF THE WIND
CHILL CALCULATION TO TANK. THIS MAKES PICKING OUT WIND CHILL
VALUES RATHER TRICKY...HOWEVER THINGS ARE ALREADY RELATIVELY CALM
IN OHIO AS OF 9 PM. WITH LITTLE CHANCE OF WINDS INCREASING...AND
NO CHANCE OF SUB -25F TEMPERATURES IN THE COUNTIES CURRENTLY IN
THE WARNINGS IN OHIO...THE WARNINGS WERE CONVERTED TO ADVISORIES
FOR CARROLL/COLUMBIANA/BEAVER. ELSEWHERE...NO CHANGES TO THE WIND
CHILL HEADLINES FOR THE MOMENT.
A LITTLE MORE ON THE COLDER TEMPERATURES...THE CURRENT FORECAST OF
-11F FOR PITTSBURGH COMBINES THE WARMER GUIDANCE OF -4/-5 OF THE
MAV/MET GUIDANCE...WITH EXPLICIT MODEL OUTPUT OF GENERALLY AROUND
-10F...WITH HIGHER RESOLUTION MODEL OUTPUT OF AROUND -15F...AND
ECMWF GUIDANCE AT -12F. TEMPERATURES AS COLD AS TONIGHT ARE
NOTORIOUSLY FICKLE TO PREDICT DUE TO EXTREME SENSITIVITY TO
WIND/CLOUDS/SNOW DEPTH/AGE OF SNOW ON THE GROUND/LENGTH OF
DARKNESS. SEVERAL OF THESE FACTORS WILL BE WORKING FOR
US...HOWEVER SEVERAL OF THEM WILL ALSO BE WORKING AGAINST US. WITH
EACH PASSING DAY IN FEBRUARY...INTENSE COLD BECOMES MORE DIFFICULT
TO SUSTAIN...AND THE FACT OF THE MATTER IS...IT HAS NEVER BEEN
-10F OR COLDER THIS LATE IN PITTSBURGH...EVER. THINK ABOUT THAT
FOR A MINUTE. FOR ECMWF STATISTICAL GUIDANCE TO BE FORECASTING NOT
ONLY A RECORD LOW...BUT A TEMPERATURE AS COLD AS WE HAVE EVER BEEN
THIS LATE IN THE YEAR...THE EXACT NUMBER BECOMES LESS MEANINGFUL
THAN THE FACT THAT IT MAY WELL END UP BEING A NIGHT LIKE WE HAVE
NEVER SEEN THIS LATE IN FEBRUARY BEFORE. NEEDLESS TO SAY...IT WILL
BE DANGEROUSLY COLD TONIGHT...BY ANY STANDARD. FRIES
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
MODELS HAVE CONTINUED TO TREND FARTHER NORTH WITH THE SYSTEM ON
SATURDAY SO ADJUSTMENTS WERE MADE TO THE PREVIOUS FORECAST TO LIMIT
PRECIP TYPE TO ALL SNOW EXCEPT FOR SOUTH OF THE PA BORDER WHERE
WAA ON SATURDAY/SATURDAY EVENING STILL LOOKS STRONG ENOUGH TO
RESULT IN A CHANGEOVER TO RAIN...HOWEVER...ANY RAIN THAT DOES FALL
WILL LIKELY FREEZE AT THE SFC GIVEN THE EXTREMELY LOW TEMPERATURES
AS OF LATE. THERE IS STILL A FAIR AMOUNT OF UNCERTAINTY WITH THIS
SYSTEM REGARDING PRECIPITATION TYPE AND SNOW AMOUNTS BUT DETAILS
SHOULD BECOME MUCH CLEARER OVER THE NEXT 24 HOURS.
SURFACE TEMPS WILL BE EXTREMELY DIFFICULT THANKS TO THE FROZEN
GROUND AND SNOW PACK.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS LOW PRESSURE TRACKS NORTHEAST...MUCH OF THE FORECAST AREA WILL BE
IN THE WARM SECTOR SATURDAY NIGHT INTO SUNDAY BEFORE THE COLD FRONT
MOVES THROUGH SUNDAY AFTERNOON. THIS WILL RESULT IN ADDITIONAL
CHALLENGES DETERMINING PRECIPITATION TYPE AS THE SYSTEM MOVES
THROUGH BY SUNDAY NIGHT. HIGH PRESSURE SHOULD ALLOW FOR A BRIEF
PERIOD OF DRY WEATHER BEFORE MORE PRECIPITATION MOVES IN FOR TUESDAY
AND WEDNESDAY. AFTER SUNDAYS COLD FRONT...TEMPERATURES WILL FALL
WELL BELOW NORMAL ONCE AGAIN...WITH HIGHS IN THE 20S.
&&
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
VFR/MVFR STRATUS IS EXPECTED TO CONTINUE THROUGH THE
AFTERNOON/EVENING...WITH ZZV POSSIBLY BEING THE ONE EXCEPTION.
GUSTS ARE EXPECTED TO CONTINUE/DEVELOP THROUGH THE AFTERNOON
HOURS...WITH MOST SITES REACHING 20-25 KTS. GUSTS SHOULD BEGIN TO
EASE OFF DURING THE EVENING HOURS AS HIGH PRESSURE MOVES INTO THE
REGION. CLOUDS SHOULD ALSO MANAGE TO SCATTER OUT DURING THAT TIME
PERIOD. WINDS ARE NOT EXPECTED TO EXCEED 10 KTS ON FRIDAY.
OUTLOOK.../FRIDAY THROUGH TUESDAY/...
VFR WILL CONTINUE FRIDAY AFTERNOON. RESTRICTIONS ARE EXPECTED
SATURDAY AND SUNDAY WITH APPROACH AND PASSAGE OF LOW PRESSURE. A
MIX OF PRECIPITATION TYPES IS EXPECTED...INCLUDING THE POSSIBILITY
FOR FREEZING RAIN. WIDESPREAD PRECIPITATION SHOULD BE OVER BY
SUNDAY NIGHT...WITH VFR CONDITIONS EXPECTED MONDAY INTO TUESDAY.
&&
.CLIMATE...
PITTSBURGH RECORD LOW TEMPERATURE FOR FRI FEB 20 ... MINUS 2
MOST RECENTLY SET IN 1936.
MORGANTOWN RECORD LOW TEMPERATURE FOR FRI FEB 20 ... 0 IN 1966.
ZANESVILLE RECORD LOW TEMPERATURE FOR FRI FEB 20 ... MINUS 6 IN
1979.
PITTSBURGH RECORD COLDEST HIGH TEMPERATURE FOR FRI FEB 20 ... 9
IN 1896.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WIND CHILL WARNING UNTIL NOON EST FRIDAY FOR MDZ001.
OH...WIND CHILL ADVISORY UNTIL NOON EST FRIDAY FOR OHZ039>041-
048>050-057>059-068-069.
PA...WIND CHILL ADVISORY UNTIL NOON EST FRIDAY FOR PAZ020-021-029-
031-073-075.
WIND CHILL WARNING UNTIL NOON EST FRIDAY FOR PAZ007>009-
013>016-022-023-074-076.
WV...WIND CHILL ADVISORY UNTIL NOON EST FRIDAY FOR WVZ001>004-012-
021-022.
WIND CHILL WARNING UNTIL NOON EST FRIDAY FOR WVZ023-041.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
627 PM EST THU FEB 19 2015
.SYNOPSIS...
SCATTERED SNOW SHOWERS AND FLURRIES WILL END EARLY THIS EVENING AS
THE DRY ARCTIC AIR MASS CONTINUES TO POUR INTO THE REGION. DRY
WEATHER WILL CONTINUE ON FRIDAY BEFORE THE NEXT STORM SYSTEM
IMPACTS THE REGION ON SATURDAY.
&&
.NEAR TERM /THROUGH FRIDAY/...
WITH THE DENDRITIC GROWTH LAYER ON THE SURFACE AND CYCLONIC COLD
ADVECTING FLOW CONTINUING OVER THE GREAT LAKES...WIDESPREAD LONG
TRACK SNOW SHOWER BANDS CONTINUE DOWNWIND FROM THE OPEN WATERS OF
LAKES SUPERIOR...MICHIGAN...AND EVEN A PINCH OF LAKE HURON. LAKE
ERIE HAS BECOME ENTIRELY CUT OFF FROM UPWARD MOISTURE FLUX DUE TO
ICE COVER...AND GIVEN THE GREATLY INCREASING DEPTH...SIGNIFICANT
HEAT FLUX THROUGH THE ICE SEEMS UNLIKELY TO BE ENOUGH TO RADICALLY
CHANGE THE INSTABILITY REGIME OVER THE LAKE TO INDUCE INCREASED
SNOW BAND INTENSITY DOWNWIND OF IT. THAT SAID...BANDS FROM LAKE
MICHIGAN SEEM TO CONTINUE TO BE MAKING THEIR WAY ALL THE WAY
THROUGH EASTERN OHIO AND WESTERN PENNSYLVANIA FAIRLY EASILY EARLY
THIS EVENING...HOWEVER THAT IS LIKELY TO CHANGE RATHER DRASTICALLY
AS DIURNALLY INDUCED INSTABILITY WANES.
MODEL SOUNDINGS DO FAVOR ONE BAND SURVIVING IN SOME FORM OR
ANOTHER OFF THE SOUTH END OF LAKE MICHIGAN UNTIL THE LATE
EVENING...WITH MODEL RH FIELDS FROM THE NAM AND HRRR BOTH
INDICATING SOME BOUNDARY LAYER CONVERGENCE AND AN INCREASED RH
FIELD SAGGING SOUTHWARD FROM THE I-70 CORRIDOR THROUGH THE EVENING
HOURS. BEHIND THAT...DRIER BOUNDARY LAYER RH VALUES DO COME INTO
THE AREA...AND MODEL SOUNDINGS FAVOR WEAKER MIXING AND A FAR LESS
UNSTABLE ENVIRONMENT OVERNIGHT. ADDITIONALLY...A FAR WEAKER
SURFACE PRESSURE GRADIENT IS EVIDENT ON ALL GUIDANCE
OVERNIGHT...SO WHILE GUSTY NORTHWEST FLOW IS EVIDENT EARLY THIS
EVENING...THAT GRADIENT WILL WEAKEN RATHER SUBSTANTIALLY OUTSIDE
THE HIGHER AREAS OVERNIGHT. WHILE THIS WILL ALLOW FOR THE WIND
COMPONENT OF THE WIND CHILL TO RELAX...THE COMBINATION OF LOWER RH
VALUES AND SOME MODEST DECOUPLING OVER THE LOWER ELEVATIONS WILL
ALLOW FOR THE TEMPERATURE PORTION OF THE WIND CHILL CALCULATION TO
TANK. AS A RESULT...NO CHANGES WERE MADE TO THE WIND CHILL
HEADLINES WITH A BIT LIGHTER WINDS BUT COLDER TEMPERATURES
GENERALLY FORECAST AT THE MOMENT OVERNIGHT INTO THE MORNING HOURS.
A LITTLE MORE ON THE COLDER TEMPERATURES...THE CURRENT FORECAST OF
-11F FOR PITTSBURGH COMBINES THE WARMER GUIDANCE OF -4/-5 OF THE
MAV/MET GUIDANCE...WITH EXPLICIT MODEL OUTPUT OF GENERALLY AROUND
-10F...WITH HIGHER RESOLUTION MODEL OUTPUT OF AROUND -15F...AND
ECMWF GUIDANCE AT -12F. TEMPERATURES AS COLD AS TONIGHT ARE
NOTORIOUSLY FICKLE TO PREDICT DUE TO EXTREME SENSITIVITY TO
WIND/CLOUDS/SNOW DEPTH/AGE OF SNOW ON THE GROUND/LENGTH OF
DARKNESS. SEVERAL OF THESE FACTORS WILL BE WORKING FOR
US...HOWEVER SEVERAL OF THEM WILL ALSO BE WORKING AGAINST US. WITH
EACH PASSING DAY IN FEBRUARY...INTENSE COLD BECOMES MORE DIFFICULT
TO SUSTAIN...AND THE FACT OF THE MATTER IS...IT HAS NEVER BEEN
-10F OR COLDER THIS LATE IN PITTSBURGH...EVER. THINK ABOUT THAT
FOR A MINUTE. FOR ECMWF STATISTICAL GUIDANCE TO BE FORECASTING NOT
ONLY A RECORD LOW...BUT A TEMPERATURE AS COLD AS WE HAVE EVER BEEN
THIS LATE IN THE YEAR...THE EXACT NUMBER BECOMES LESS MEANINGFUL
THAN THE FACT THAT IT MAY WELL END UP BEING A NIGHT LIKE WE HAVE
NEVER SEEN THIS LATE IN FEBRUARY BEFORE. NEEDLESS TO SAY...IT WILL
BE DANGEROUSLY COLD TONIGHT...BY ANY STANDARD. FRIES
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
MODELS HAVE CONTINUED TO TREND FARTHER NORTH WITH THE SYSTEM ON
SATURDAY SO ADJUSTMENTS WERE MADE TO THE PREVIOUS FORECAST TO LIMIT
PRECIP TYPE TO ALL SNOW EXCEPT FOR SOUTH OF THE PA BORDER WHERE
WAA ON SATURDAY/SATURDAY EVENING STILL LOOKS STRONG ENOUGH TO
RESULT IN A CHANGEOVER TO RAIN...HOWEVER...ANY RAIN THAT DOES FALL
WILL LIKELY FREEZE AT THE SFC GIVEN THE EXTREMELY LOW TEMPERATURES
AS OF LATE. THERE IS STILL A FAIR AMOUNT OF UNCERTAINTY WITH THIS
SYSTEM REGARDING PRECIPITATION TYPE AND SNOW AMOUNTS BUT DETAILS
SHOULD BECOME MUCH CLEARER OVER THE NEXT 24 HOURS.
SURFACE TEMPS WILL BE EXTREMELY DIFFICULT THANKS TO THE FROZEN
GROUND AND SNOW PACK.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS LOW PRESSURE TRACKS NORTHEAST...MUCH OF THE FORECAST AREA WILL BE
IN THE WARM SECTOR SATURDAY NIGHT INTO SUNDAY BEFORE THE COLD FRONT
MOVES THROUGH SUNDAY AFTERNOON. THIS WILL RESULT IN ADDITIONAL
CHALLENGES DETERMINING PRECIPITATION TYPE AS THE SYSTEM MOVES
THROUGH BY SUNDAY NIGHT. HIGH PRESSURE SHOULD ALLOW FOR A BRIEF
PERIOD OF DRY WEATHER BEFORE MORE PRECIPITATION MOVES IN FOR TUESDAY
AND WEDNESDAY. AFTER SUNDAYS COLD FRONT...TEMPERATURES WILL FALL
WELL BELOW NORMAL ONCE AGAIN...WITH HIGHS IN THE 20S.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
VFR/MVFR STRATUS IS EXPECTED TO CONTINUE THROUGH THE
AFTERNOON/EVENING...WITH ZZV POSSIBLY BEING THE ONE EXCEPTION.
GUSTS ARE EXPECTED TO CONTINUE/DEVELOP THROUGH THE AFTERNOON
HOURS...WITH MOST SITES REACHING 20-25 KTS. GUSTS SHOULD BEGIN TO
EASE OFF DURING THE EVENING HOURS AS HIGH PRESSURE MOVES INTO THE
REGION. CLOUDS SHOULD ALSO MANAGE TO SCATTER OUT DURING THAT TIME
PERIOD. WINDS ARE NOT EXPECTED TO EXCEED 10 KTS ON FRIDAY.
OUTLOOK.../FRIDAY THROUGH TUESDAY/...
VFR WILL CONTINUE FRIDAY AFTERNOON. RESTRICTIONS ARE EXPECTED
SATURDAY AND SUNDAY WITH APPROACH AND PASSAGE OF LOW PRESSURE. A
MIX OF PRECIPITATION TYPES IS EXPECTED...INCLUDING THE POSSIBILITY
FOR FREEZING RAIN. WIDESPREAD PRECIPITATION SHOULD BE OVER BY
SUNDAY NIGHT...WITH VFR CONDITIONS EXPECTED MONDAY INTO TUESDAY.
&&
.CLIMATE...
PITTSBURGH RECORD COLDEST HIGH TEMPERATURE FOR THU FEB 19 ... 9
IN 1936.
PITTSBURGH RECORD LOW TEMPERATURE FOR FRI FEB 20 ... MINUS 2 MOST
RECENTLY SET IN 1936.
MORGANTOWN RECORD LOW TEMPERATURE FOR FRI FEB 20 ... 0 IN 1966.
ZANESVILLE RECORD LOW TEMPERATURE FOR FRI FEB 20 ... MINUS 6 IN
1979.
PITTSBURGH RECORD COLDEST HIGH TEMPERATURE FOR FRI FEB 20 ... 9
IN 1896.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WIND CHILL WARNING UNTIL NOON EST FRIDAY FOR MDZ001.
WIND CHILL ADVISORY UNTIL 7 PM EST THIS EVENING FOR MDZ001.
OH...WIND CHILL ADVISORY UNTIL NOON EST FRIDAY FOR OHZ039-048>050-
057>059-068-069.
WIND CHILL WARNING UNTIL NOON EST FRIDAY FOR OHZ040-041.
WIND CHILL ADVISORY UNTIL 7 PM EST THIS EVENING FOR OHZ040-041.
PA...WIND CHILL ADVISORY UNTIL NOON EST FRIDAY FOR PAZ021-029-031-
073-075.
WIND CHILL WARNING UNTIL NOON EST FRIDAY FOR PAZ007>009-
013>016-020-022-023-074-076.
WIND CHILL ADVISORY UNTIL 7 PM EST THIS EVENING FOR PAZ007>009-
013>016-020-022-023-074-076.
WV...WIND CHILL ADVISORY UNTIL NOON EST FRIDAY FOR WVZ001>004-012-
021-022.
WIND CHILL WARNING UNTIL NOON EST FRIDAY FOR WVZ023-041.
WIND CHILL ADVISORY UNTIL 7 PM EST THIS EVENING FOR WVZ023-041.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1240 AM EST WED FEB 18 2015
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 354 PM EST TUE FEB 17 2015
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW DEEP UPR TROF
CENTERED OVER SW HUDSON BAY DOWNSTREAM OF HI AMPLITUDE RDG ALONG THE
W COAST. H5/H7/H85 TEMPS UNDER THE CORE OF THE COLDEST AIR ARND NW
ONTARIO/NE MANITOBA ARE AS LO AS -46C/-33C/-30C RESPECTIVELY.
DESPITE CONSIDERABLE ICE COVER ON LK SUP...ESPECIALLY OVER THE W...
AND THE APRCH OF A WEAK SHRTWV RDG/SOME DNVA...SOME LES CONTINUES IN
THE SN BELTS IMPACTED BY THE COLD NW LLVL FLOW LEFT IN THE WAKE OF A
DISTURBANCE WHICH PASSED LAST NGT. THE MOST OPEN WATER IS LOCATED
OVER THE SCENTRAL PART OF THE LK...SO THE MORE NMRS SN SHOWERS ARE
MOVING INTO THE E HALF OF ALGER COUNTY. LOOKING UPSTREAM...THERE IS
A SHRTWV DIGGING SSEWD THRU MANITOBA. DESPITE PWAT UNDER 0.10
INCH...THERE IS A LARGE AREA OF CLD COVER AND SOME LIGHT SN UNDER
THE DPVA/DEEP LYR QVECTOR CNVGC AHEAD OF THIS SHRTWV WITH 00Z-12Z H5
HGT FALLS AOA 100M AND SOME FAIRLY DEEP MSTR THRU H7 DEPICTED ON THE
12Z YPL ROAB.
MAIN FCST CONCERNS IN THE SHORT TERM FOCUS ON GOING HEADLINES...LES
COVERAGE/AMOUNTS AND TEMPS/LO WIND CHILLS.
TNGT...DIGGING MANITOBA SHRTWV IS PROGGED TO TRACK SSEWD THRU MN AND
INTO WI...WITH DPVA/DEEP LYR QVECTOR CNVGC ON THE CYC SIDE OF THE
TRACK OF THIS FEATURE IMPACTING UPR MI. MODEL FCST SDNGS SHOW DCRSG
STABILITY/DEEPENING MSTR LATE TODAY OVER THE W AND THEN ESPECIALLY
NEAR THE WI BORDER CLOSER TO THE TRACK OF THE DISTURBANCE INTO THE
OVERNGT. WITH THE SHRTWV PASSAGE...THERE WL ALSO BE A REINFORCING
COLD FROPA/WSHFT TO THE NNW THAT IS FCST TO DRAG H85 TEMPS AS LO AS -
30C OVER THE W BY 12Z WED. EARLIER IN THE SEASON...THIS SETUP WOULD
HAVE PRESENTED AN OPPORTUNITY FOR SOME SGNFT LES. BUT CONSIDERABLE
ICE COVER OVER LK SUP AND ABSENCE OF DGZ WITH INFLUX OF BITTERLY
COLD AIR WL GREATLY LIMIT SN TOTALS. THE BEST CHC FOR SOME HEAVIER
LES WL BE IN ALGER COUNTY...WHICH WL BE DOWNWIND OF THE MORE OPEN
WATERS OVER SCENTRAL LK SUP AND IN AREA OF ENHANCED LLVL LAND BREEZE
TYPE CNVGC EXACERBATED BY THE ICE COVER ON LK SUP. BUT WSHFT FM THE
WNW TO NNW IN THE WAKE OF THE COLD FROPA WL SHIFT THE FOCUS FOR THE
MORE NMRS SN SHOWERS FM THE E HALF OF THE COUNTY TO AREAS ARND OR
JUST W OF MUNISING. ALTHOUGH THE DOWNSLOPE NATURE OF THE NW FLOW WL
LIMIT POPS OVER THE SCENTRAL...WL CARRY SOME SCHC/CHC POPS IN THAT
AREA TO ACCOUNT FOR THE PERIOD OF DEEPER HI RH AND DYNAMIC FORCING.
SINCE THE PRES GRADIENT WL TIGHTEN IN THE WAKE OF THE SHRWV
PASSAGE/COLD FROPA...H925 WINDS ARE FCST TO INCRS TO 20-25 KTS
OVERNGT. ALSO...GROWING ICE COVER ON LK SUP WL LIMIT MODERATION OF
THE INCOMING ARCTIC AIRMASS. THESE FACTORS WL RESULT IN AT LEAST
MARGINAL WIND CHILL ADVY CONDITIONS OVER MUCH OF THE W HALF OF UPR
MI AS THE H85 TEMP TUMBLES TOWARD -30C TOWARD 12Z. ALTHOUGH WIND
SPEEDS MAY BE MARGINAL FOR THE ADVY CRITERIA... OPTED TO MAINTAIN
THE GOING HEADLINES AND ADD BARAGA/MARQUETTE COUNTIES TO THE
HEADLINE.
WED...ARRIVAL OF DNVA/DEEP LYR QVECTOR DVGC/SUBSIDENCE IN THE WAKE
OF THE SHRTWV PASSAGE WL TEND TO SUPPRESS LINGERING SN SHOWERS
DOWNWIND OF LK SUP AND END THE PCPN COMPLETELY OVER THE SCENTRAL
DURING THE MRNG. AS THE FLOW BACKS A BIT TO THE NW AGAIN...ALGER
COUNTY WL REMAIN THE FOCUS FOR THE MORE NMRS AND HEAVIER SN
SHOWERS...ESPECIALLY IN THE MRNG. MAINTAINED WINTER WX HEADLINE FOR
ALGER COUNTY TNGT THRU WED AND WED NGT /SEE LONG TERM DISCUSSION.
WITH H85 TEMPS REMAINING NOT FAR FM -30C...EXPECT MAX TEMPS TO
STRUGGLE TO REACH ZERO...ESPCIALLY OVER THE NW HALF WHERE THE WIND
CHILL HEADLINE WL RUN UNTIL 18Z.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 440 PM EST TUE FEB 17 2015
THE OVERALL PATTERN WILL CONTINUE TO BE DOMINATED BY A MID/UPPER
LEVEL RIDGE FROM THE ERN PACIFIC INTO WRN CANADA AND A TROUGH FROM
HUDSON BAY INTO THE CENTRAL AND ERN CONUS. THIS WILL ALLOW ADDITIONAL
BOUTS OF COLD AIR TO MOVE INTO THE WRN LAKES INTO NEXT WEEK WITH
TEMPERATURES REMAINING WELL BELOW NORMAL.
WED NIGHT...THE MAIN FCST ISSUE CONTINUES TO BE THE VERY COLD AIR.
ALTHOUGH WINDS WILL GENERALLY BE LESS THAN 10 MPH...WITH AIR TEMPS
FALLING INTO THE -10 TO -20 RANGE...WIND CHILL VALUES COULD AGAIN
DROP INTO THE -20 TO -30 RANGE EVEN WITH THE WINDS ONLY AROUND 5 MPH.
THE HIGH RES MODELS WERE RELATIVELY CONSISTENT IN FOCUSING LES INTO
ALGER COUNTY DOWNSTREAM OF THE REMAINING OPEN PATCH OF WATER IN THE
DEEPEST PORTION OF LAKE SUPERIOR. FAVORABLE LOW LEVEL CONV IN THE
NARROW OPEN AREA COULD PRODUCE A HEAVIER SNOW BAND WITH ADDITIONAL
SNOW AMOUNTS IN THE 1 TO 4 INCH RANGE ARE EXPECTED.
HOWEVER...CONFIDENCE IS LOW GIVEN THE CHANGING/INCREASING AMOUNTS OF
ICE COVER.
THU AND THU NIGHT...THE ARCTIC HIGH WILL BUILD INTO THE AREA WITH
MAINLY LIGHT WINDS. EXPECT ENOUGH CLEARING FOR TEMPS TO DROP OFF
INTO THE -15 TO 25 RANGE WITH SOME LOCAL READINGS POSSIBLY DOWN TO
AROUND -30F. HOWEVER...MAINLY LIGHT/CALM WINDS SHOULD PREVAIL. ANY
REMAINING LES INTO ALGER COUNTY WILL DIMINISH AND LIFT OFFSHORE AS
WINDS BECOME SW BY EVENING.
FRI INTO FRI NIGHT...A TROUGH MOVING TOWARD THE WRN LAKES WILL
RESULT IN A BROAD WAA PATTERN THROUGH THE REGION. THE MODELS WERE IN
RELATIVELY GOOD AGREEMENT THAT DEEP LAYER ISENTROPIC ASCENT AHEAD
THIS FEATURES WILL PRODUCE SOME LIGHT SNOW. FOR NOW...POPS WERE LEFT
IN THE CHANCE RANGE...BUT WOULD EXPECT THAT IF THE TRENDS HOLD UP A
HIGHER POP LOW QPF/SNOW EVENT WILL DEVELOP WITH OVERALL SNOW AMOUNTS
OF AN INCH OR TWO. THE INCREASING SW FLOW OFF OF LAKE MICHIGAN COULD
BRING A SNOW BAND INTO THE FAR SE CWA BUT WITH THE EXTENSIVE ICE
THAT HAS DEVELOPED OVER NRN LAKE MI...CONFIDENCE IS LOW THAT IT WILL
BRING SIGNIFICANT ADDITIONAL SNOW AMOUNTS.
SAT-TUE...ANOTHER BATCH OF ARCTIC AIR WILL SLIDE INTO THE AREA BY
SUN WITH TEMPS FROM ZERO TO 10 BELOW SAT NIGHT AND IN THE SINGLE
DIGITS SUN. NW WINDS COULD BRING SOME LIGHT SNOW SHOWERS TO THE AREA
FROM ANY REMAINING GAPS IN THE ICE COVER...MAINLY OVER THE EAST
HALF. FCST UNCERTAINTY IS HIGHER BY TUE...AS THE 00Z/12Z ECMWF
REMAINED SIGNIFICANTLY MORE AGGRESSIVE WITH THE NEXT SHRTWV AND
AMOUNT OF COLD MOVING IN.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1239 AM EST WED FEB 18 2015
LAKE EFFECT SNOW BANDS CONTINUE OVER WESTERN LAKE SUPERIOR AND HAVE
OCCASIONALLY PRODUCED IFR CONDITIONS AT BOTH KCMX AND KIWD LATE THIS
EVENING. COLDER AIR TO MOVE INTO HE WESTERN U.P. OVERNIGHT AS ANOTHER
SURGE OF ARCTIC AIR ARRIVES WITH THE PASSAGE OF 5H TROF AXIS. THIS
WILL KEEP LES GOING FOR A WHILE WITH IFR/LOW END MVFR CONDITIONS
CONTINUING THROUGH THE NIGHT WITH IMPROVEMENT EXPECTED BY DAYBREAK AS
SUBSIDENCE STRENGTHENS. LES TO GRADUALLY END DURING THE DAYTIME HOURS
WITH CIGS IMPROVING. AT KSAW...NW FLOW NOT AS CONDUCIVE TO LOWER CIGS
AND VISIBILITIES THERE SO EXPECT MVFR CONDITIONS TO PREVAIL THERE
THROUGH THE FORECAST. THERE IS SOME CONCERN THAT SOME BLOWING AND
DRIFTING SNOW MAY PRODUCE IFR VISIBILITIES THERE DURING THE DAY AS
WINDS PICK UP A BIT AND BECOME GUSTY AT TIMES BUT HAVE LEFT THIS OUT
OF THE FORECAST AT THIS TIME. &&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 354 PM EST TUE FEB 17 2015
WINDS WILL BE MAINLY 30 KTS OR LESS THE REST OF THE WEEK INTO NEXT
WEEKEND. THERE MAY BE A FEW GALE FORCE GUSTS IN THE VCNTY OF STRONG
BAND OF LAKE EFFECT SNOW OVER SCENTRAL LK SUPERIOR LATE TONIGHT
THROUGH WED NIGHT. HEAVY FREEZING SPRAY COULD DEVELOP IN THE LIMITED
OPEN WATER OF SCENTRAL LK SUPERIOR ON WED NIGHT. ICE COVERAGE WILL
CONTINUE TO EXPAND THROUGH THE WEEK AS ARCTIC AIRMASS SETTLES OVER
THE AREA.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 7 AM EST THURSDAY FOR MIZ006.
WIND CHILL ADVISORY FROM 4 AM EST /3 AM CST/ EARLY THIS MORNING
TO 1 PM EST /NOON CST/ THIS AFTERNOON FOR MIZ001>005-
009>011-084.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...JLB
AVIATION...RJT
MARINE...KC
AREA FORECAST DISCUSSION
NWS RALEIGH NC
411 PM EST WED FEB 18 2015
.SYNOPSIS...AN ARCTIC COLD FRONT WILL CROSS THE AREA THIS
EVENING. FRIGID HIGH PRESSURE WILL BUILD OVER THE AREA TONIGHT
THROUGH THROUGH EARLY SATURDAY... BRINGING DANGEROUSLY
COLD TEMPERATURES.
&&
.NEAR TERM/TONIGHT/...
AS OF 341 PM WEDNESDAY...
...A WINTER WEATHER ADVISORY FOR BLACK ICE WILL BE ISSUED OVER THE
NORTHWESTERN AND NORTHERN PIEDMONT AND COASTAL PLAIN FOR TONIGHT...
...WIND CHILL ADVISORIES IN EFFECT FOR DANGEROUS LIFE THREATENING
WIND CHILLS TONIGHT THROUGH FRIDAY MORNING....
A WINTER WEATHER ADVISORY WILL BE ISSUED FOR A GOOD PORTION OF THE
PIEDMONT... ROUGHLY ALONG THE I-40/85 CORRIDOR REGION FROM THE TRIAD
TO THE TRIANGLE... THEN THE COASTAL PLAIN I-95 CORRIDOR (GOLDSBORO
NORTHWARD TO THE VA BORDER). THIS ADVISORY WILL BE FOR AREAS THAT
STILL HAVE SIGNIFICANT ICE THAT WILL REFREEZE QUICKLY THIS EVENING.
ANY MELTWATER THAT IS RUNNING ACROSS ANY SURFACES EARLY THIS
EVENING WILL FLASH FREEZE. THIS INCLUDES PARKING LOTS... SIDE
WALKS... STREETS... AND ROADS. MANY OF THE URBAN NEIGHBORHOODS OF
THE PIEDMONT STILL HAVE SIGNIFICANT ICE COVER ON THE STREETS/ROADS
THAT ARE PROTECTED FROM THE SUN. EVAPORATION IN THE EXTREME COLD DRY
AIR SHOULD HELP DRY UP MOST BLACK ICE BEFORE 900 AM THURSDAY WHEN
THE ADVISORY WILL END.
NOW TO THE ACTUAL WEATHER FALLING FROM THE SKY...
A BURST OF SNOW OR BRIEF SNOW SHOWERS WILL MOVE QUICKLY FROM
WEST TO EAST ACROSS THE REGION BETWEEN 300 AND 700 PM AND EXITING
THE NE ZONES AROUND 700 PM. ALTHOUGH THE SNOW SHOWERS WILL LAST LESS
THAN AN HOUR A QUICK DUSTING OR COATING MAY RESULT GIVEN THE
CONVECTIVE NATURE OF THE REFLECTIVITY RETURNS CURRENTLY PRODUCING
LESS THAN 0.3 OF AN INCH OF SNOW (PER REPORTS FROM THE TRIAD
REGION). THESE SNOW SHOWERS WILL QUICKLY COOL THE SURFACE
TEMPERATURES DUE TO EVAPORATIVE COOLING DOWN TO FREEZING.
THIS MAY LEAD TO A FEW SLICK SPOTS (NEW SLICK SPOTS) MAINLY ON
ELEVATED SURFACES. MOST OF THIS CONCERN WILL REMAIN NORTH AND
WEST OF FAYETTEVILLE AND GOLDSBORO... ALTHOUGH A BRIEF FLURRY IS
POSSIBLE THERE AS WELL.
AS FOR THE COLD WAVE... THE ACTUAL ARCTIC FRONT WAS PUSHING INTO THE
FOOTHILLS AS OF MID AFTERNOON. THE LEADING EDGE WILL SURGE EAST
ACROSS THE REGION EARLY TO MID EVENING. FORCING OUT AHEAD OF THE
FRONT HAS LED TO THE BANDS OF CONVECTIVE SNOW SHOWERS THAT WILL
AFFECT THE REGION THROUGH EARLY EVENING... WITH ONLY A FEW FLURRIES
EXPECTED BEHIND THE FRONT. WIND GUSTS TO 45 MPH WILL BE LIKELY
WITH THE SNOW SHOWERS AND THE PASSAGE OF THE FRONT. THE ARCTIC AIR
IS LAGGING THE FRONT BY A FEW HOURS BUT THE BOTTOM WILL BEGIN TO
FALL OUT AS THE EVENING GOES ON.
WE EXPECT THAT THE MOS GUIDANCE TEMPERATURES WILL NOT BE COLD ENOUGH
WITH OUR LOWS TONIGHT AND WITH HIGHS ON THURSDAY. LOWS BY DAYBREAK
SHOULD BE 5-10 IN THE NW RANGING TO AROUND 15 IN FAYETTEVILLE AND
GOLDSBORO. COMBINED WITH WINDS 15-25 MPH... MINIMUM WIND CHILLS WILL
RANGE BETWEEN 0 TO NEARLY 15 BELOW DURING MUCH OF THURSDAY MORNING.
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
AS OF 411 PM WEDNESDAY...
...COLD WAVE CONTINUES...
COMBINED WITH WINDS 15-25 MPH... MINIMUM WIND CHILLS WILL RANGE
BETWEEN 0 TO NEARLY 15 BELOW DURING MUCH OF THURSDAY MORNING. WITH
THE CAA CONTINUING ON THURSDAY TEMPERATURES WILL STRUGGLE TO REACH
10-15 NW AND 20 IN THE SE.
THURSDAY NIGHT... WE WILL GO WITH LOWS OF 0-5... WITH SOME AREAS IN
THE NORTH CENTRAL PIEDMONT LIKELY DIPPING TO NEAR 5 BELOW. WIND
CHILL READINGS WILL NOT BE AS BAD... BUT ACTUAL TEMPERATURES WILL
CREATE DANGEROUS TO LIFE THREATENING COLD NONETHELESS.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 300 AM WEDNESDAY...
THE LONG TERM BEGINS WITH A POSITIVELY TILTED UPPER LEVEL TROUGH
EXTENDING DOWN THE EAST COAST WITH A STRONG SURFACE HIGH CENTERED
OVER THE OHIO VALLEY. THIS WILL KEEP CENTRAL NC ROOTED IN THE COLD
AIR ADVECTION REGIME WITH NORTHERLY SFC FLOW AND NWLY FLOW ALOFT.
VERY COLD AND DRY AIRMASS WITH HIGHS ONLY IN THE LOW TO MID 20S. THE
SFC HIGH DRIFTS EAST AND SETS UP OVER EASTERN NC FRIDAY NIGHT WHICH
WILL TURN WINDS AROUND TO SOUTHERLY RETURN FLOW. THIS WILL NOT BE IN
TIME TO HELP TEMPS ALL THAT MUCH AS LOWS WILL BE IN THE MID TEENS.
STILL THIS IS WARMER THAN PREVIOUS NIGHTS. BACK TO WEST...AN
INVERTED TROUGH EXTENDING INTO THE TENNESSEE VALLEY FROM A PARENT
LOW OVER NORTH TEXAS WILL BE PRODUCING AN AREA OF STRONG LOW LEVEL
CONVERGENCE AND PRECIPITATION THAT IS THE PRECURSOR TO OUR NEXT
SYSTEM. INCREASING CLOUDS CAN BE EXPECTED AHEAD OF THIS SYSTEM LATE
FRIDAY NIGHT INTO SATURDAY MORNING.
OVERALL...MODELS HAVE COME INTO BETTER AGREEMENT WITH REGARD TO THE
EVOLUTION OF THE SYSTEM APPROACHING FROM THE WEST ON SATURDAY. THERE
STILL ARE FINER DIFFERENCES THAT MAY MATTER CONSIDERABLY IN HOW THE
FINAL SCENARIO PLAYS OUT. FIRST...THE EUROPEAN HAS PICKED UP THE LOW
PRESSURE WEST OF THE MOUNTAINS THAT THE GFS WAS SHOWING YESTERDAY. A
MUCH STRONGER WAVE IN THE UPPER LEVEL PATTERN OVER TEXAS IN THE GFS
IS PRODUCING A MUCH STRONGER LOW AND IS SLOWER WITH ITS PROGRESSION
UP THE BACK OF THE COLD FRONT. THIS WILL NOT MATTER IN REGARDS TO
POTENTIAL WINTER P-TYPE ON SATURDAY AS MUCH AS IT WILL FOR THE
TIMING OF THE ADVANCEMENT OF THE COLD FRONT THROUGH THE STATE ON
SUNDAY WHICH IS FASTER IN THE ECMWF. ANOTHER COMPROMISE THE MODELS
HAVE MADE IS WITH THE IN-SITU DAMMING SCENARIO AS THE SFC HIGH MOVES
OUT TO SEA. BOTH MODELS ARE NOW PRODUCING A WEDGE FRONT BUT IT IS
MUCH WEAKER IN THE GFS THEN PRIOR RUNS AND THE HIGH PUSHES FURTHER
OUT TO SEA FASTER THAN PREVIOUS RUNS AND THUS BOTH MODELS LOSE THE
WEDGE QUICKLY LATE SATURDAY AFTERNOON/EVENING. BECAUSE OF THIS...THE
OOZ RUN OF THE GFS HAS TRENDED A BIT WARMER AS ISENTROPIC LIFT WILL
BE LESS PRONOUNCED EARLIER IN THE DAY.
THE UPSHOT IN THE FORECAST SOUNDINGS IS A REAL GRAB BAG OF POTENTIAL
PRECIPITATION TYPES FOR THE TRIAD WITH APPRECIABLE DIFFERENCES
BETWEEN THE THERMAL PROFILES EVEN BETWEEN KGSO AND KINT. THE GENERAL
TREND WILL BE A GREATER LIKELIHOOD OF SNOW NORTH AND WEST AND LESS
SO APPROACHING GREENSBORO AND POINTS SOUTH AND EAST WHERE SLEET AND
EVEN FREEZING RAIN COULD BE MORE LIKELY. VERY EARLY FOR THESE
DETAILS TO BE IRONED OUT SO WE WILL CALL IT WINTERY MIX FOR NOW.
PRECIPITATION DOES LOOK CONFINED TO THE TRIAD HOWEVER AND POINTS
EAST OF HIGHWAY 1 SHOULD REMAIN DRY FOR MUCH OF THE DAY ON SATURDAY.
HIGHS GENERALLY IN THE LOWER 40S. EXPECT A NON-DIURNAL TEMPERATURE
CURVE FOR SATURDAY NIGHT WITH TEMPERATURES BEGINNING TO WARM
CONSIDERABLY AFTER 00Z SUNDAY AS WARM AIR ADVECTION AHEAD OF THE
COLD FRONT BEGINS. LOWS IN THE MID TO UPPER 30S OCCURRING EARLY IN
THE EVENING.
RAIN ASSOCIATED WITH THE COLD FRONT WILL MOVE IN FOR SUNDAY.
CONFIDENCE IN THIS BEING ALL LIQUID IS HIGH CONSIDERING THE
OVERNIGHT RISE IN TEMPERATURES WHICH WILL CONTINUE ON SUNDAY AND THE
LOSS OF SATURATION ALOFT IN THE ICE NUCLEATION ZONE. IN
FACT...TEMPERATURES WARM SO MUCH IN THE LOW LEVELS THAT INSTABILITY
CREEPS IN BY LATE SUNDAY AFTERNOON/EARLY EVENING AND LOW AND MID
LEVEL LAPSE RATES INCREASE. RISES ARE MINIMAL BUT WOULD NOT RULE OUT
THE CHANCE FOR A HEAVY CONVECTIVE SHOWER OR ISOLATED THUNDERSTORM.
HIGHS IN THE MID TO UPPER 50S. PRECIPITATION IS EXPECTED TO END
AFTER 6Z MONDAY. TOTAL QPF AMOUNTS ARE VERY UNCERTAIN AT THIS TIME
BUT EXPECT MORE IN THE TRIAD THAN POINTS EAST. LOWS IN THE MID TO
UPPER 30S.
COLDER AND DRIER BEHIND THE FRONT WITH NORTHEASTERLY SFC FLOW ON
MONDAY WITH HIGHS IN THE MID 40S AND LOWS MONDAY NIGHT IN THE UPPER
20S. DRY FOR TUESDAY AS WELL AS LOW PRESSURE MOVES INTO THE GREAT
LAKES REGION. HIGHS IN THE MID TO UPPER 40S.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
AS OF 640 AM WEDNESDAY...
PRIMARY AVIATION CONCERNS NEXT 24 HRS: SUB-VFR CIGS/VSBYS AT FAY
EARLY THIS MORNING... A PERIOD OF MVFR CIGS AND SCATTERED SNOW
SHOWERS TODAY FROM MID AFTERNOON TO EARLY EVENING... AND
STRONG/GUSTY WINDS THIS AFTERNOON THROUGH THE END OF THE TAF VALID
PERIOD.
AN AREA OF IFR-LIFR FOG OVER THE SOUTHERN SECTIONS OF CENTRAL NC...
INCLUDING FAY... WILL DRIFT SLOWLY EASTWARD OVER THE NEXT FEW
HOURS... ACCORDING TO THE LATEST HRRR GUIDANCE. MAINLY VFR
CONDITIONS ELSEWHERE THIS MORNING... EXCEPT FOR A CLUSTER OF MVFR
CLOUDS AT GSO PRIOR TO 14Z. A CLIPPER COLD FRONT WILL SWEEP ACROSS
THE AREA THIS AFTERNOON/EARLY EVENING... AT APPROXIMATELY 18Z-20Z AT
INT/GSO... 20Z-22Z AT RDU... AND 22Z-00Z AT FAY. A SHORT PERIOD
(LIKELY AROUND 2-3 HRS AT MOST) OF MVFR CIGS/VSBYS IN SNOW SHOWERS
IS EXPECTED WITH FRONTAL PASSAGE. SURFACE WINDS FROM THE SW WILL
INCREASE IN THE FEW HOURS BEFORE FRONTAL PASSAGE... THEN REMAIN
STRONG AND GUSTY AS THEY SHIFT TO NW BEHIND THE FRONT... LASTING
THROUGH 06Z. VFR CIGS/VSBYS ARE EXPECTED AFTER FRONTAL PASSAGE.
LOOKING BEYOND 12Z THU MORNING: BRISK AND OCCASIONALLY GUSTY NW
SURFACE WINDS WILL PERSIST THROUGH THU. VFR CONDITIONS ARE EXPECTED
TO DOMINATE THROUGH FRI NIGHT WITH FRIGID HIGH PRESSURE BUILDING IN.
ANOTHER STORM SYSTEM APPROACHING FROM THE WEST AND SW WILL BRING
LIKELY SUB-VFR CONDITIONS WITH PRECIPITATION STARTING IN THE NW
EARLY SAT MORNING BEFORE SPREADING AREAWIDE SAT. SUB-VFR CONDITIONS
AND STRONG/SHIFTING WINDS WILL LAST THROUGH SUN AS A WARM FRONT
TRACKS NORTHWARD THROUGH THE REGION. -GIH
&&
.CLIMATE...
THE FOLLOWING ARE RECORD LOW AND LOW MAXIMUM TEMPERATURES FOR
FEBRUARY 19TH...AND 20TH...FOR GSO...RDU...AND FAY...
RECORD LOWS
GSO RDU FAY
FEBRUARY 19: 12 IN 1979 11 IN 1979 8 IN 1958
FEBRUARY 20: 14 IN 1934 13 IN 1979 12 IN 1958
FEBRUARY 21: 13 IN 1959 8 IN 1896 16 IN 1958
RECORD LOW MAXIMUMS
GSO RDU FAY
FEBRUARY 19: 32 IN 1958 31 IN 1903 26 IN 1979
FEBRUARY 20: 29 IN 1947 32 IN 1947 37 IN 1972
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM EST FRIDAY FOR
NCZ007>011-021>028-038>043-073>078-083>086-088-089.
WINTER WEATHER ADVISORY FOR THE PIEDMONT AND COASTAL PLAIN THROUGH
900 AM THURSDAY.
&&
$$
SYNOPSIS...BADGETT
NEAR TERM...BADGETT
SHORT TERM...BADGETT
LONG TERM...ELLIS
AVIATION...HARTFIELD
CLIMATE...RAH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
341 PM EST WED FEB 18 2015
.SYNOPSIS...AN ARCTIC COLD FRONT WILL CROSS THE AREA THIS
EVENING. FRIGID HIGH PRESSURE WILL BUILD OVER THE AREA TONIGHT
THROUGH THROUGH EARLY SATURDAY... BRINGING DANGEROUSLY
COLD TEMPERATURES.
&&
.NEAR TERM/TONIGHT/...
AS OF 341 PM WEDNESDAY...
...A WINTER WEATHER ADVISORY FOR BLACK ICE WILL BE ISSUED OVER THE
NORTHWESTERN AND NORTHERN PIEDMONT AND COASTAL PLAIN FOR TONIGHT...
...WIND CHILL ADVISORIES IN EFFECT FOR DANGEROUS LIFE THREATENING
WIND CHILLS TONIGHT THROUGH FRIDAY MORNING....
A WINTER WEATHER ADVISORY WILL BE ISSUED FOR A GOOD PORTION OF THE
PIEDMONT... ROUGHLY ALONG THE I-40/85 CORRIDOR REGION FROM THE TRIAD
TO THE TRIANGLE... THEN THE COASTAL PLAIN I-95 CORRIDOR (GOLDSBORO
NORTHWARD TO THE VA BORDER). THIS ADVISORY WILL BE FOR AREAS THAT
STILL HAVE SIGNIFICANT ICE THAT WILL REFREEZE QUICKLY THIS EVENING.
ANY MELTWATER THAT IS RUNNING ACROSS ANY SURFACES EARLY THIS
EVENING WILL FLASH FREEZE. THIS INCLUDES PARKING LOTS... SIDE
WALKS... STREETS... AND ROADS. MANY OF THE URBAN NEIGHBORHOODS OF
THE PIEDMONT STILL HAVE SIGNIFICANT ICE COVER ON THE STREETS/ROADS
THAT ARE PROTECTED FROM THE SUN. EVAPORATION IN THE EXTREME COLD DRY
AIR SHOULD HELP DRY UP MOST BLACK ICE BEFORE 900 AM THURSDAY WHEN
THE ADVISORY WILL END.
NOW TO THE ACTUAL WEATHER FALLING FROM THE SKY...
A BURST OF SNOW OR BRIEF SNOW SHOWERS WILL MOVE QUICKLY FROM
WEST TO EAST ACROSS THE REGION BETWEEN 300 AND 700 PM AND EXITING
THE NE ZONES AROUND 700 PM. ALTHOUGH THE SNOW SHOWERS WILL LAST LESS
THAN AN HOUR A QUICK DUSTING OR COATING MAY RESULT GIVEN THE
CONVECTIVE NATURE OF THE REFLECTIVITY RETURNS CURRENTLY PRODUCING
LESS THAN 0.3 OF AN INCH OF SNOW (PER REPORTS FROM THE TRIAD
REGION). THESE SNOW SHOWERS WILL QUICKLY COOL THE SURFACE
TEMPERATURES DUE TO EVAPORATIVE COOLING DOWN TO FREEZING.
THIS MAY LEAD TO A FEW SLICK SPOTS (NEW SLICK SPOTS) MAINLY ON
ELEVATED SURFACES. MOST OF THIS CONCERN WILL REMAIN NORTH AND
WEST OF FAYETTEVILLE AND GOLDSBORO... ALTHOUGH A BRIEF FLURRY IS
POSSIBLE THERE AS WELL.
AS FOR THE COLD WAVE... THE ACTUAL ARCTIC FRONT WAS PUSHING INTO THE
FOOTHILLS AS OF MID AFTERNOON. THE LEADING EDGE WILL SURGE EAST
ACROSS THE REGION EARLY TO MID EVENING. FORCING OUT AHEAD OF THE
FRONT HAS LED TO THE BANDS OF CONVECTIVE SNOW SHOWERS THAT WILL
AFFECT THE REGION THROUGH EARLY EVENING... WITH ONLY A FEW FLURRIES
EXPECTED BEHIND THE FRONT. WIND GUSTS TO 45 MPH WILL BE LIKELY
WITH THE SNOW SHOWERS AND THE PASSAGE OF THE FRONT. THE ARCTIC AIR
IS LAGGING THE FRONT BY A FEW HOURS BUT THE BOTTOM WILL BEGIN TO
FALL OUT AS THE EVENING GOES ON.
WE EXPECT THAT THE MOS GUIDANCE TEMPERATURES WILL NOT BE COLD ENOUGH
WITH OUR LOWS TONIGHT AND WITH HIGHS ON THURSDAY. LOWS BY DAYBREAK
SHOULD BE 5-10 IN THE NW RANGING TO AROUND 15 IN FAYETTEVILLE AND
GOLDSBORO. COMBINED WITH WINDS 15-25 MPH... MINIMUM WIND CHILLS WILL
RANGE BETWEEN 0 TO NEARLY 15 BELOW DURING MUCH OF THURSDAY MORNING.
WITH THE CAA CONTINUING ON THURSDAY TEMPERATURES WILL STRUGGLE TO
REACH 10-15 NW AND 20 IN THE SE.
THURSDAY NIGHT... WE WILL GO WITH LOWS OF 0-5... WITH SOME AREAS IN
THE NORTH CENTRAL PIEDMONT LIKELY DIPPING TO NEAR 5 BELOW. WIND
CHILL READINGS WILL NOT BE AS BAD... BUT ACTUAL TEMPERATURES
WILL CREATE DANGEROUS TO LIFE THREATENING COLD NONETHELESS.
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
AS OF 330 AM WEDNESDAY...
CONFIDENCE IN DANGEROUSLY COLD WEATHER IS INCREASING. BRISK AND
GUSTY WINDS ARE A NEAR CERTAINTY BEHIND THIS ARCTIC FRONT... WITH
THE MOMENTUM OF THE COLD DENSE AIR AND TIGHT MSLP GRADIENT. EXPECT
SUSTAINED WINDS FROM THE NW AROUND 15-25 MPH GUSTING AS HIGH AS 30-
35 MPH TONIGHT. WINDS SHOULD ABATE A BIT THU/THU NIGHT AS THE
INITIAL COLD SURGE WANES... HOWEVER THE MSLP GRADIENT REMAINS TIGHT
ENOUGH TO SUPPORT SUSTAINED NW WINDS OF AROUND 15 MPH GUSTING TO
AROUND 25 MPH THU INTO THU NIGHT. MEANWHILE... RECORD-BUSTING COLD
TEMPERATURES ARE ALSO IMMINENT... WITH MODEL THICKNESSES... BUFR
SOUNDING THERMAL STRUCTURE... STATISTICAL GUIDANCE... AND UPSTREAM
CURRENT CONDITIONS ALL SUPPORTING VERY COLD READINGS. EXPECT LOWS
TONIGHT OF 7-15... HIGHS ONLY 15-23 THU... AND LOWS THU NIGHT OF 1
BELOW TO 7 ABOVE. THESE TEMPS AND WINDS TOGETHER WILL GENERATE SOME
OF THE LOWEST WIND CHILL READINGS WE`VE SEEN IN MANY YEARS...
DROPPING BELOW 0F NEAR OR SHORTLY AFTER MIDNIGHT. WILL POST A WIND
CHILL ADVISORY FOR ALL OF CENTRAL NC STARTING AT MIDNIGHT. WHILE
WIND CHILL VALUES ARE EXPECTED TO INCH ABOVE THE 0F MARK BETWEEN
ABOUT 12 NOON AND 5 PM THU... READINGS ARE LIKELY TO DIVE DOWN WELL
BELOW ZERO ONCE AGAIN AFTER 5 PM THU... STAYING DANGEROUSLY LOW
(EVEN APPROACHING -10F) THROUGH MID MORNING FRI. SINCE THU`S TIME
FRAME OF ABOVE-ZERO WIND CHILLS WILL BE SO SHORT... AND SINCE WE`D
STILL LIKE EVERYONE TO TAKE PROPER PRECAUTIONS AND NOT BE COMPLACENT
DURING THE DAYTIME AS WIND CHILLS WILL STILL BE VERY COLD... HAVE
OPTED TO TAKE THE UNUSUAL STEP (IN THIS UNUSUAL WEATHER SITUATION)
OF EXTENDING THE WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT ALL THE
WAY THROUGH FRI MORNING. EXPECT MOSTLY CLEAR SKIES THROUGH THIS
PERIOD... ALTHOUGH FLAT BROKEN STRATOCU THU MAINLY IN THE AFTERNOON
SHOULD BRING MOSTLY CLOUDY SKIES FOR A FEW HOURS. -GIH
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 300 AM WEDNESDAY...
THE LONG TERM BEGINS WITH A POSITIVELY TILTED UPPER LEVEL TROUGH
EXTENDING DOWN THE EAST COAST WITH A STRONG SURFACE HIGH CENTERED
OVER THE OHIO VALLEY. THIS WILL KEEP CENTRAL NC ROOTED IN THE COLD
AIR ADVECTION REGIME WITH NORTHERLY SFC FLOW AND NWLY FLOW ALOFT.
VERY COLD AND DRY AIRMASS WITH HIGHS ONLY IN THE LOW TO MID 20S. THE
SFC HIGH DRIFTS EAST AND SETS UP OVER EASTERN NC FRIDAY NIGHT WHICH
WILL TURN WINDS AROUND TO SOUTHERLY RETURN FLOW. THIS WILL NOT BE IN
TIME TO HELP TEMPS ALL THAT MUCH AS LOWS WILL BE IN THE MID TEENS.
STILL THIS IS WARMER THAN PREVIOUS NIGHTS. BACK TO WEST...AN
INVERTED TROUGH EXTENDING INTO THE TENNESSEE VALLEY FROM A PARENT
LOW OVER NORTH TEXAS WILL BE PRODUCING AN AREA OF STRONG LOW LEVEL
CONVERGENCE AND PRECIPITATION THAT IS THE PRECURSOR TO OUR NEXT
SYSTEM. INCREASING CLOUDS CAN BE EXPECTED AHEAD OF THIS SYSTEM LATE
FRIDAY NIGHT INTO SATURDAY MORNING.
OVERALL...MODELS HAVE COME INTO BETTER AGREEMENT WITH REGARD TO THE
EVOLUTION OF THE SYSTEM APPROACHING FROM THE WEST ON SATURDAY. THERE
STILL ARE FINER DIFFERENCES THAT MAY MATTER CONSIDERABLY IN HOW THE
FINAL SCENARIO PLAYS OUT. FIRST...THE EUROPEAN HAS PICKED UP THE LOW
PRESSURE WEST OF THE MOUNTAINS THAT THE GFS WAS SHOWING YESTERDAY. A
MUCH STRONGER WAVE IN THE UPPER LEVEL PATTERN OVER TEXAS IN THE GFS
IS PRODUCING A MUCH STRONGER LOW AND IS SLOWER WITH ITS PROGRESSION
UP THE BACK OF THE COLD FRONT. THIS WILL NOT MATTER IN REGARDS TO
POTENTIAL WINTER P-TYPE ON SATURDAY AS MUCH AS IT WILL FOR THE
TIMING OF THE ADVANCEMENT OF THE COLD FRONT THROUGH THE STATE ON
SUNDAY WHICH IS FASTER IN THE ECMWF. ANOTHER COMPROMISE THE MODELS
HAVE MADE IS WITH THE IN-SITU DAMMING SCENARIO AS THE SFC HIGH MOVES
OUT TO SEA. BOTH MODELS ARE NOW PRODUCING A WEDGE FRONT BUT IT IS
MUCH WEAKER IN THE GFS THEN PRIOR RUNS AND THE HIGH PUSHES FURTHER
OUT TO SEA FASTER THAN PREVIOUS RUNS AND THUS BOTH MODELS LOSE THE
WEDGE QUICKLY LATE SATURDAY AFTERNOON/EVENING. BECAUSE OF THIS...THE
OOZ RUN OF THE GFS HAS TRENDED A BIT WARMER AS ISENTROPIC LIFT WILL
BE LESS PRONOUNCED EARLIER IN THE DAY.
THE UPSHOT IN THE FORECAST SOUNDINGS IS A REAL GRAB BAG OF POTENTIAL
PRECIPITATION TYPES FOR THE TRIAD WITH APPRECIABLE DIFFERENCES
BETWEEN THE THERMAL PROFILES EVEN BETWEEN KGSO AND KINT. THE GENERAL
TREND WILL BE A GREATER LIKELIHOOD OF SNOW NORTH AND WEST AND LESS
SO APPROACHING GREENSBORO AND POINTS SOUTH AND EAST WHERE SLEET AND
EVEN FREEZING RAIN COULD BE MORE LIKELY. VERY EARLY FOR THESE
DETAILS TO BE IRONED OUT SO WE WILL CALL IT WINTERY MIX FOR NOW.
PRECIPITATION DOES LOOK CONFINED TO THE TRIAD HOWEVER AND POINTS
EAST OF HIGHWAY 1 SHOULD REMAIN DRY FOR MUCH OF THE DAY ON SATURDAY.
HIGHS GENERALLY IN THE LOWER 40S. EXPECT A NON-DIURNAL TEMPERATURE
CURVE FOR SATURDAY NIGHT WITH TEMPERATURES BEGINNING TO WARM
CONSIDERABLY AFTER 00Z SUNDAY AS WARM AIR ADVECTION AHEAD OF THE
COLD FRONT BEGINS. LOWS IN THE MID TO UPPER 30S OCCURRING EARLY IN
THE EVENING.
RAIN ASSOCIATED WITH THE COLD FRONT WILL MOVE IN FOR SUNDAY.
CONFIDENCE IN THIS BEING ALL LIQUID IS HIGH CONSIDERING THE
OVERNIGHT RISE IN TEMPERATURES WHICH WILL CONTINUE ON SUNDAY AND THE
LOSS OF SATURATION ALOFT IN THE ICE NUCLEATION ZONE. IN
FACT...TEMPERATURES WARM SO MUCH IN THE LOW LEVELS THAT INSTABILITY
CREEPS IN BY LATE SUNDAY AFTERNOON/EARLY EVENING AND LOW AND MID
LEVEL LAPSE RATES INCREASE. RISES ARE MINIMAL BUT WOULD NOT RULE OUT
THE CHANCE FOR A HEAVY CONVECTIVE SHOWER OR ISOLATED THUNDERSTORM.
HIGHS IN THE MID TO UPPER 50S. PRECIPITATION IS EXPECTED TO END
AFTER 6Z MONDAY. TOTAL QPF AMOUNTS ARE VERY UNCERTAIN AT THIS TIME
BUT EXPECT MORE IN THE TRIAD THAN POINTS EAST. LOWS IN THE MID TO
UPPER 30S.
COLDER AND DRIER BEHIND THE FRONT WITH NORTHEASTERLY SFC FLOW ON
MONDAY WITH HIGHS IN THE MID 40S AND LOWS MONDAY NIGHT IN THE UPPER
20S. DRY FOR TUESDAY AS WELL AS LOW PRESSURE MOVES INTO THE GREAT
LAKES REGION. HIGHS IN THE MID TO UPPER 40S.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
AS OF 640 AM WEDNESDAY...
PRIMARY AVIATION CONCERNS NEXT 24 HRS: SUB-VFR CIGS/VSBYS AT FAY
EARLY THIS MORNING... A PERIOD OF MVFR CIGS AND SCATTERED SNOW
SHOWERS TODAY FROM MID AFTERNOON TO EARLY EVENING... AND
STRONG/GUSTY WINDS THIS AFTERNOON THROUGH THE END OF THE TAF VALID
PERIOD.
AN AREA OF IFR-LIFR FOG OVER THE SOUTHERN SECTIONS OF CENTRAL NC...
INCLUDING FAY... WILL DRIFT SLOWLY EASTWARD OVER THE NEXT FEW
HOURS... ACCORDING TO THE LATEST HRRR GUIDANCE. MAINLY VFR
CONDITIONS ELSEWHERE THIS MORNING... EXCEPT FOR A CLUSTER OF MVFR
CLOUDS AT GSO PRIOR TO 14Z. A CLIPPER COLD FRONT WILL SWEEP ACROSS
THE AREA THIS AFTERNOON/EARLY EVENING... AT APPROXIMATELY 18Z-20Z AT
INT/GSO... 20Z-22Z AT RDU... AND 22Z-00Z AT FAY. A SHORT PERIOD
(LIKELY AROUND 2-3 HRS AT MOST) OF MVFR CIGS/VSBYS IN SNOW SHOWERS
IS EXPECTED WITH FRONTAL PASSAGE. SURFACE WINDS FROM THE SW WILL
INCREASE IN THE FEW HOURS BEFORE FRONTAL PASSAGE... THEN REMAIN
STRONG AND GUSTY AS THEY SHIFT TO NW BEHIND THE FRONT... LASTING
THROUGH 06Z. VFR CIGS/VSBYS ARE EXPECTED AFTER FRONTAL PASSAGE.
LOOKING BEYOND 12Z THU MORNING: BRISK AND OCCASIONALLY GUSTY NW
SURFACE WINDS WILL PERSIST THROUGH THU. VFR CONDITIONS ARE EXPECTED
TO DOMINATE THROUGH FRI NIGHT WITH FRIGID HIGH PRESSURE BUILDING IN.
ANOTHER STORM SYSTEM APPROACHING FROM THE WEST AND SW WILL BRING
LIKELY SUB-VFR CONDITIONS WITH PRECIPITATION STARTING IN THE NW
EARLY SAT MORNING BEFORE SPREADING AREAWIDE SAT. SUB-VFR CONDITIONS
AND STRONG/SHIFTING WINDS WILL LAST THROUGH SUN AS A WARM FRONT
TRACKS NORTHWARD THROUGH THE REGION. -GIH
&&
.CLIMATE...
THE FOLLOWING ARE RECORD LOW AND LOW MAXIMUM TEMPERATURES FOR
FEBRUARY 19TH...AND 20TH...FOR GSO...RDU...AND FAY...
RECORD LOWS
GSO RDU FAY
FEBRUARY 19: 12 IN 1979 11 IN 1979 8 IN 1958
FEBRUARY 20: 14 IN 1934 13 IN 1979 12 IN 1958
FEBRUARY 21: 13 IN 1959 8 IN 1896 16 IN 1958
RECORD LOW MAXIMUMS
GSO RDU FAY
FEBRUARY 19: 32 IN 1958 31 IN 1903 26 IN 1979
FEBRUARY 20: 29 IN 1947 32 IN 1947 37 IN 1972
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM EST FRIDAY FOR
NCZ007>011-021>028-038>043-073>078-083>086-088-089.
WINTER WEATHER ADVISORY FOR THE PIEDMONT AND COASTAL PLAIN THROUGH
900 AM THURSDAY.
&&
$$
SYNOPSIS...BADGETT
NEAR TERM...BADGETT
SHORT TERM...HARTFIELD
LONG TERM...ELLIS
AVIATION...HARTFIELD
CLIMATE...RAH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1205 PM EST WED FEB 18 2015
.SYNOPSIS...AN ARCTIC COLD FRONT WILL CROSS THE AREA THIS AFTERNOON
THROUGH EARLY EVENING. FRIGID HIGH PRESSURE WILL BUILD OVER THE AREA
THIS EVENING THROUGH EARLY SATURDAY... BRINGING DANGEROUSLY COLD
TEMPERATURES.
&&
.NEAR TERM /TODAY/...
AS OF 1205 PM WEDNESDAY...
...A SPECIAL WEATHER STATEMENT CONTINUES FOR PATCHY RESIDUAL ICE ON
AREA ROADS THIS AFTERNOON... CAUTION ON AREA ROADS IS STILL
ADVISED...
ALSO... A COUPLE OF BANDS OF SNOW SHOWERS WILL BE HANDLED BY SPECIAL
WEATHER STATEMENTS THIS AFTERNOON AS THE WARMER TEMPERATURES SHOULD
PREVENT ANY ADDITIONAL ACCUMULATIONS ON THE ROADS. THE MAIN WEATHER
HAZARD FROM THE SNOW SHOWERS WILL LIKELY BE THE GUSTY WIND TO NEAR
40 MPH AS THE FRONT COMES THROUGH. A QUICK BURST OF LOW VISIBILITIES
WITH THE SNOW SHOWERS WILL OCCUR. THE SHOWERS SHOULD ONLY LAST 15-20
MINUTES AT ANY ONE LOCATION FURTHER LIMITING THE ACCUMULATION
POTENTIAL.
THE TEMPERATURES WERE RISING NICELY OUT AHEAD OF THE ARCTIC FRONT
APPROACHING FROM THE WEST. NOON READINGS WERE ALREADY IN THE MID TO
UPPER 30S. THE ONLY THING HOLDING THE SANDHILLS AND SOUTHERN
PIEDMONT BACK WAS THE RESIDUAL LOW CLOUDS AND FOG... FROM THE
WIDESPREAD DENSE FOG EARLIER TODAY. THESE WILL BE LIFTING OUT TO THE
NE BY EARLY TO MID AFTERNOON. EXPECT TEMPERATURES TO CONTINUE TO
WARM IN ADVANCE OF THE BOUNDARY DRIVEN BY INCREASING SOUTHWESTERLY
FLOW AT 15-20 MPH. HIGHS GENERALLY IN THE LOWER TO MID 40S
EXPECTED... EXCEPT 30S HOLDING ON FROM THE NW PART OF THE TRIAD TO
NEAR ROXBORO. TEMPERATURES WILL BEGIN TO FALL RAPIDLY WITH THE WIND
SHIFT TO THE WNW BEHIND THE FRONT.
THE ACTUAL FRONT WAS PUSHING INTO THE MOUNTAINS AT NOON. THE LEADING
EDGE WAS LOCATED ALONG THE BLUE RIDGE AS NOTED BY THE BANDS OF SNOW
SHOWERS EXTENDING FROM JUST WEST OF HICKORY TO JUST WEST OF MOUNT
AIRY... MOVING EAST. THIS FRONT WILL SURGE OFF THE MOUNTAINS
REACHING THE TRIAD REGION BETWEEN 100 AND 300 PM... THEN THE
TRIANGLE BETWEEN 300 AND 500 PM. THIS IS THE TARGET AREA FOR A BAND
OR TWO OF SNOW SHOWERS THIS AFTERNOON ALONG AND JUST BEHIND THE
FRONT. WINDS WILL BECOME STRONG AND GUSTY AS THE FRONT MOVES
THROUGH. AGAIN... ACCOMPANIED BY A QUICK BURST OF SNOW SHOWERS THAT
ARE NOT EXPECTED TO CAUSE ANY ADDITIONAL TRAVEL HAZARDS.
LOOK FOR THE SPECIAL WEATHER STATEMENTS TO HANDLE THIS ARCTIC FRONT
AND SNOW SHOWERS THIS AFTERNOON.
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
AS OF 330 AM WEDNESDAY...
CONFIDENCE IN DANGEROUSLY COLD WEATHER IS INCREASING. BRISK AND
GUSTY WINDS ARE A NEAR CERTAINTY BEHIND THIS ARCTIC FRONT... WITH
THE MOMENTUM OF THE COLD DENSE AIR AND TIGHT MSLP GRADIENT. EXPECT
SUSTAINED WINDS FROM THE NW AROUND 15-25 MPH GUSTING AS HIGH AS 30-
35 MPH TONIGHT. WINDS SHOULD ABATE A BIT THU/THU NIGHT AS THE
INITIAL COLD SURGE WANES... HOWEVER THE MSLP GRADIENT REMAINS TIGHT
ENOUGH TO SUPPORT SUSTAINED NW WINDS OF AROUND 15 MPH GUSTING TO
AROUND 25 MPH THU INTO THU NIGHT. MEANWHILE... RECORD-BUSTING COLD
TEMPERATURES ARE ALSO IMMINENT... WITH MODEL THICKNESSES... BUFR
SOUNDING THERMAL STRUCTURE... STATISTICAL GUIDANCE... AND UPSTREAM
CURRENT CONDITIONS ALL SUPPORTING VERY COLD READINGS. EXPECT LOWS
TONIGHT OF 7-15... HIGHS ONLY 15-23 THU... AND LOWS THU NIGHT OF 1
BELOW TO 7 ABOVE. THESE TEMPS AND WINDS TOGETHER WILL GENERATE SOME
OF THE LOWEST WIND CHILL READINGS WE`VE SEEN IN MANY YEARS...
DROPPING BELOW 0F NEAR OR SHORTLY AFTER MIDNIGHT. WILL POST A WIND
CHILL ADVISORY FOR ALL OF CENTRAL NC STARTING AT MIDNIGHT. WHILE
WIND CHILL VALUES ARE EXPECTED TO INCH ABOVE THE 0F MARK BETWEEN
ABOUT 12 NOON AND 5 PM THU... READINGS ARE LIKELY TO DIVE DOWN WELL
BELOW ZERO ONCE AGAIN AFTER 5 PM THU... STAYING DANGEROUSLY LOW
(EVEN APPROACHING -10F) THROUGH MID MORNING FRI. SINCE THU`S TIME
FRAME OF ABOVE-ZERO WIND CHILLS WILL BE SO SHORT... AND SINCE WE`D
STILL LIKE EVERYONE TO TAKE PROPER PRECAUTIONS AND NOT BE COMPLACENT
DURING THE DAYTIME AS WIND CHILLS WILL STILL BE VERY COLD... HAVE
OPTED TO TAKE THE UNUSUAL STEP (IN THIS UNUSUAL WEATHER SITUATION)
OF EXTENDING THE WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT ALL THE
WAY THROUGH FRI MORNING. EXPECT MOSTLY CLEAR SKIES THROUGH THIS
PERIOD... ALTHOUGH FLAT BROKEN STRATOCU THU MAINLY IN THE AFTERNOON
SHOULD BRING MOSTLY CLOUDY SKIES FOR A FEW HOURS. -GIH
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 300 AM WEDNESDAY...
THE LONG TERM BEGINS WITH A POSITIVELY TILTED UPPER LEVEL TROUGH
EXTENDING DOWN THE EAST COAST WITH A STRONG SURFACE HIGH CENTERED
OVER THE OHIO VALLEY. THIS WILL KEEP CENTRAL NC ROOTED IN THE COLD
AIR ADVECTION REGIME WITH NORTHERLY SFC FLOW AND NWLY FLOW ALOFT.
VERY COLD AND DRY AIRMASS WITH HIGHS ONLY IN THE LOW TO MID 20S. THE
SFC HIGH DRIFTS EAST AND SETS UP OVER EASTERN NC FRIDAY NIGHT WHICH
WILL TURN WINDS AROUND TO SOUTHERLY RETURN FLOW. THIS WILL NOT BE IN
TIME TO HELP TEMPS ALL THAT MUCH AS LOWS WILL BE IN THE MID TEENS.
STILL THIS IS WARMER THAN PREVIOUS NIGHTS. BACK TO WEST...AN
INVERTED TROUGH EXTENDING INTO THE TENNESSEE VALLEY FROM A PARENT
LOW OVER NORTH TEXAS WILL BE PRODUCING AN AREA OF STRONG LOW LEVEL
CONVERGENCE AND PRECIPITATION THAT IS THE PRECURSOR TO OUR NEXT
SYSTEM. INCREASING CLOUDS CAN BE EXPECTED AHEAD OF THIS SYSTEM LATE
FRIDAY NIGHT INTO SATURDAY MORNING.
OVERALL...MODELS HAVE COME INTO BETTER AGREEMENT WITH REGARD TO THE
EVOLUTION OF THE SYSTEM APPROACHING FROM THE WEST ON SATURDAY. THERE
STILL ARE FINER DIFFERENCES THAT MAY MATTER CONSIDERABLY IN HOW THE
FINAL SCENARIO PLAYS OUT. FIRST...THE EUROPEAN HAS PICKED UP THE LOW
PRESSURE WEST OF THE MOUNTAINS THAT THE GFS WAS SHOWING YESTERDAY. A
MUCH STRONGER WAVE IN THE UPPER LEVEL PATTERN OVER TEXAS IN THE GFS
IS PRODUCING A MUCH STRONGER LOW AND IS SLOWER WITH ITS PROGRESSION
UP THE BACK OF THE COLD FRONT. THIS WILL NOT MATTER IN REGARDS TO
POTENTIAL WINTER P-TYPE ON SATURDAY AS MUCH AS IT WILL FOR THE
TIMING OF THE ADVANCEMENT OF THE COLD FRONT THROUGH THE STATE ON
SUNDAY WHICH IS FASTER IN THE ECMWF. ANOTHER COMPROMISE THE MODELS
HAVE MADE IS WITH THE IN-SITU DAMMING SCENARIO AS THE SFC HIGH MOVES
OUT TO SEA. BOTH MODELS ARE NOW PRODUCING A WEDGE FRONT BUT IT IS
MUCH WEAKER IN THE GFS THEN PRIOR RUNS AND THE HIGH PUSHES FURTHER
OUT TO SEA FASTER THAN PREVIOUS RUNS AND THUS BOTH MODELS LOSE THE
WEDGE QUICKLY LATE SATURDAY AFTERNOON/EVENING. BECAUSE OF THIS...THE
OOZ RUN OF THE GFS HAS TRENDED A BIT WARMER AS ISENTROPIC LIFT WILL
BE LESS PRONOUNCED EARLIER IN THE DAY.
THE UPSHOT IN THE FORECAST SOUNDINGS IS A REAL GRAB BAG OF POTENTIAL
PRECIPITATION TYPES FOR THE TRIAD WITH APPRECIABLE DIFFERENCES
BETWEEN THE THERMAL PROFILES EVEN BETWEEN KGSO AND KINT. THE GENERAL
TREND WILL BE A GREATER LIKELIHOOD OF SNOW NORTH AND WEST AND LESS
SO APPROACHING GREENSBORO AND POINTS SOUTH AND EAST WHERE SLEET AND
EVEN FREEZING RAIN COULD BE MORE LIKELY. VERY EARLY FOR THESE
DETAILS TO BE IRONED OUT SO WE WILL CALL IT WINTERY MIX FOR NOW.
PRECIPITATION DOES LOOK CONFINED TO THE TRIAD HOWEVER AND POINTS
EAST OF HIGHWAY 1 SHOULD REMAIN DRY FOR MUCH OF THE DAY ON SATURDAY.
HIGHS GENERALLY IN THE LOWER 40S. EXPECT A NON-DIURNAL TEMPERATURE
CURVE FOR SATURDAY NIGHT WITH TEMPERATURES BEGINNING TO WARM
CONSIDERABLY AFTER 00Z SUNDAY AS WARM AIR ADVECTION AHEAD OF THE
COLD FRONT BEGINS. LOWS IN THE MID TO UPPER 30S OCCURRING EARLY IN
THE EVENING.
RAIN ASSOCIATED WITH THE COLD FRONT WILL MOVE IN FOR SUNDAY.
CONFIDENCE IN THIS BEING ALL LIQUID IS HIGH CONSIDERING THE
OVERNIGHT RISE IN TEMPERATURES WHICH WILL CONTINUE ON SUNDAY AND THE
LOSS OF SATURATION ALOFT IN THE ICE NUCLEATION ZONE. IN
FACT...TEMPERATURES WARM SO MUCH IN THE LOW LEVELS THAT INSTABILITY
CREEPS IN BY LATE SUNDAY AFTERNOON/EARLY EVENING AND LOW AND MID
LEVEL LAPSE RATES INCREASE. RISES ARE MINIMAL BUT WOULD NOT RULE OUT
THE CHANCE FOR A HEAVY CONVECTIVE SHOWER OR ISOLATED THUNDERSTORM.
HIGHS IN THE MID TO UPPER 50S. PRECIPITATION IS EXPECTED TO END
AFTER 6Z MONDAY. TOTAL QPF AMOUNTS ARE VERY UNCERTAIN AT THIS TIME
BUT EXPECT MORE IN THE TRIAD THAN POINTS EAST. LOWS IN THE MID TO
UPPER 30S.
COLDER AND DRIER BEHIND THE FRONT WITH NORTHEASTERLY SFC FLOW ON
MONDAY WITH HIGHS IN THE MID 40S AND LOWS MONDAY NIGHT IN THE UPPER
20S. DRY FOR TUESDAY AS WELL AS LOW PRESSURE MOVES INTO THE GREAT
LAKES REGION. HIGHS IN THE MID TO UPPER 40S.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
AS OF 640 AM WEDNESDAY...
PRIMARY AVIATION CONCERNS NEXT 24 HRS: SUB-VFR CIGS/VSBYS AT FAY
EARLY THIS MORNING... A PERIOD OF MVFR CIGS AND SCATTERED SNOW
SHOWERS TODAY FROM MID AFTERNOON TO EARLY EVENING... AND
STRONG/GUSTY WINDS THIS AFTERNOON THROUGH THE END OF THE TAF VALID
PERIOD.
AN AREA OF IFR-LIFR FOG OVER THE SOUTHERN SECTIONS OF CENTRAL NC...
INCLUDING FAY... WILL DRIFT SLOWLY EASTWARD OVER THE NEXT FEW
HOURS... ACCORDING TO THE LATEST HRRR GUIDANCE. MAINLY VFR
CONDITIONS ELSEWHERE THIS MORNING... EXCEPT FOR A CLUSTER OF MVFR
CLOUDS AT GSO PRIOR TO 14Z. A CLIPPER COLD FRONT WILL SWEEP ACROSS
THE AREA THIS AFTERNOON/EARLY EVENING... AT APPROXIMATELY 18Z-20Z AT
INT/GSO... 20Z-22Z AT RDU... AND 22Z-00Z AT FAY. A SHORT PERIOD
(LIKELY AROUND 2-3 HRS AT MOST) OF MVFR CIGS/VSBYS IN SNOW SHOWERS
IS EXPECTED WITH FRONTAL PASSAGE. SURFACE WINDS FROM THE SW WILL
INCREASE IN THE FEW HOURS BEFORE FRONTAL PASSAGE... THEN REMAIN
STRONG AND GUSTY AS THEY SHIFT TO NW BEHIND THE FRONT... LASTING
THROUGH 06Z. VFR CIGS/VSBYS ARE EXPECTED AFTER FRONTAL PASSAGE.
LOOKING BEYOND 12Z THU MORNING: BRISK AND OCCASIONALLY GUSTY NW
SURFACE WINDS WILL PERSIST THROUGH THU. VFR CONDITIONS ARE EXPECTED
TO DOMINATE THROUGH FRI NIGHT WITH FRIGID HIGH PRESSURE BUILDING IN.
ANOTHER STORM SYSTEM APPROACHING FROM THE WEST AND SW WILL BRING
LIKELY SUB-VFR CONDITIONS WITH PRECIPITATION STARTING IN THE NW
EARLY SAT MORNING BEFORE SPREADING AREAWIDE SAT. SUB-VFR CONDITIONS
AND STRONG/SHIFTING WINDS WILL LAST THROUGH SUN AS A WARM FRONT
TRACKS NORTHWARD THROUGH THE REGION. -GIH
&&
.CLIMATE...
THE FOLLOWING ARE RECORD LOW AND LOW MAXIMUM TEMPERATURES FOR
FEBRUARY 19TH...AND 20TH...FOR GSO...RDU...AND FAY...
RECORD LOWS
GSO RDU FAY
FEBRUARY 19: 12 IN 1979 11 IN 1979 8 IN 1958
FEBRUARY 20: 14 IN 1934 13 IN 1979 12 IN 1958
FEBRUARY 21: 13 IN 1959 8 IN 1896 16 IN 1958
RECORD LOW MAXIMUMS
GSO RDU FAY
FEBRUARY 19: 32 IN 1958 31 IN 1903 26 IN 1979
FEBRUARY 20: 29 IN 1947 32 IN 1947 37 IN 1972
&&
.RAH WATCHES/WARNINGS/ADVISORIES... WIND CHILL ADVISORY FROM
MIDNIGHT TONIGHT TO 9 AM EST FRIDAY FOR NCZ007>011-021>028-038>043-
073>078-083>086-088-089.
&&
$$ SYNOPSIS...BADGETT
NEAR TERM...BADGETT
SHORT TERM...HARTFIELD
LONG TERM...ELLIS
AVIATION...HARTFIELD
CLIMATE...RAH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
955 AM EST WED FEB 18 2015
.SYNOPSIS...AN ARCTIC COLD FRONT WILL CROSS THE AREA THIS AFTERNOON
THROUGH EARLY EVENING. FRIGID HIGH PRESSURE WILL BUILD OVER THE AREA
THIS EVENING THROUGH EARLY SATURDAY... BRINGING DANGEROUSLY COLD
TEMPERATURES. &&
.NEAR TERM /TODAY/...
AS OF 955 AM WEDNESDAY...
...WINTER WEATHER ADVISORY FOR BLACK ICE WILL BE ALLOWED TO EXPIRE
AT 1000 AM...
...A SPECIAL WEATHER STATEMENT WILL BE ISSUED AS CAUTION ON AREA
ROADS IS STILL ADVISED...
THE TEMPERATURES WERE RISING WITH THE MORNING SUNSHINE AND MOST
AREAS WILL BE ABOVE FREEZING BETWEEN 1100 AM AND NOON. WE WILL ALLOW
THE WINTER WEATHER ADVISORY TO EXPIRE. HOWEVER... EXTREME CAUTION IS
STILL ADVISED THROUGHOUT THE DAY WITH THE MELTING PROCESS ADDING TO
THE SLIPPERINESS.
THEN... EXPECT A QUICK INCREASE IN CLOUDINESS IN THE WESTERN
PIEDMONT BY EARLY AFTERNOON. THE CLIPPER FRONT AND ASSOCIATED
VORTICITY MAX NOW CROSSING THE TN VALLEY AND MIDSOUTH WILL SHIFT
ACROSS THE APPALACHIANS BY EARLY AFTERNOON... THEN OUT OVER THE
PIEDMONT DURING THE MID TO LATE AFTERNOON.
A SHOT OF LOW LEVEL MOIST UPGLIDE AT 275-280K AHEAD OF AND WITH THE
FRONT... STEEP LOW LEVEL (925-700 MB) LAPSE RATES OF 7-8 C/KM...
SURFACE WET BULB TEMPS NOT MUCH ABOVE FREEZING... AND BUFR SOUNDINGS
SHOWING GOOD SATURATION FROM JUST OFF THE SURFACE UP THROUGH THE -
20C LEVEL... ALL FOCUSED ON THE 17Z-01Z TIME FRAME... EXPECT A BRIEF
WINDOW OF SNOW SHOWERS WITH THE GREATEST COVERAGE ACROSS THE NORTH
HALF... AND A LOWER RISK OF A RAIN SHOWER/SNOW SHOWER MIX ACROSS THE
SOUTH WHERE SURFACE WET BULBS SHOULD GO ABOVE FREEZING FOR MUCH OF
THE DAY. WILL STICK WITH GOOD CHANCE POPS NORTH TAPERING TO SLIGHT
CHANCE POPS SOUTH. QPF SHOULD BE QUITE LIGHT GIVEN THE FAST
MOVEMENT... BUT WITH THE STEEP LAPSE RATES SUGGESTING A CONVECTIVE
CONTRIBUTION... WE COULD SEE A SHORT PERIOD OF HEAVIER RATES... AND
WOULDN`T BE AT ALL SURPRISED TO SEE A DUSTING TO A HALF INCH OF SNOW
IN SOME SPOTS ACROSS THE NORTHERN CWA. HIGHS FROM THE MID 30S NORTH
TO LOWER 40S SOUTH. -GIH
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
AS OF 330 AM WEDNESDAY...
CONFIDENCE IN DANGEROUSLY COLD WEATHER IS INCREASING. BRISK AND
GUSTY WINDS ARE A NEAR CERTAINTY BEHIND THIS ARCTIC FRONT... WITH
THE MOMENTUM OF THE COLD DENSE AIR AND TIGHT MSLP GRADIENT. EXPECT
SUSTAINED WINDS FROM THE NW AROUND 15-25 MPH GUSTING AS HIGH AS 30-
35 MPH TONIGHT. WINDS SHOULD ABATE A BIT THU/THU NIGHT AS THE
INITIAL COLD SURGE WANES... HOWEVER THE MSLP GRADIENT REMAINS TIGHT
ENOUGH TO SUPPORT SUSTAINED NW WINDS OF AROUND 15 MPH GUSTING TO
AROUND 25 MPH THU INTO THU NIGHT. MEANWHILE... RECORD-BUSTING COLD
TEMPERATURES ARE ALSO IMMINENT... WITH MODEL THICKNESSES... BUFR
SOUNDING THERMAL STRUCTURE... STATISTICAL GUIDANCE... AND UPSTREAM
CURRENT CONDITIONS ALL SUPPORTING VERY COLD READINGS. EXPECT LOWS
TONIGHT OF 7-15... HIGHS ONLY 15-23 THU... AND LOWS THU NIGHT OF 1
BELOW TO 7 ABOVE. THESE TEMPS AND WINDS TOGETHER WILL GENERATE SOME
OF THE LOWEST WIND CHILL READINGS WE`VE SEEN IN MANY YEARS...
DROPPING BELOW 0F NEAR OR SHORTLY AFTER MIDNIGHT. WILL POST A WIND
CHILL ADVISORY FOR ALL OF CENTRAL NC STARTING AT MIDNIGHT. WHILE
WIND CHILL VALUES ARE EXPECTED TO INCH ABOVE THE 0F MARK BETWEEN
ABOUT 12 NOON AND 5 PM THU... READINGS ARE LIKELY TO DIVE DOWN WELL
BELOW ZERO ONCE AGAIN AFTER 5 PM THU... STAYING DANGEROUSLY LOW
(EVEN APPROACHING -10F) THROUGH MID MORNING FRI. SINCE THU`S TIME
FRAME OF ABOVE-ZERO WIND CHILLS WILL BE SO SHORT... AND SINCE WE`D
STILL LIKE EVERYONE TO TAKE PROPER PRECAUTIONS AND NOT BE COMPLACENT
DURING THE DAYTIME AS WIND CHILLS WILL STILL BE VERY COLD... HAVE
OPTED TO TAKE THE UNUSUAL STEP (IN THIS UNUSUAL WEATHER SITUATION)
OF EXTENDING THE WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT ALL THE
WAY THROUGH FRI MORNING. EXPECT MOSTLY CLEAR SKIES THROUGH THIS
PERIOD... ALTHOUGH FLAT BROKEN STRATOCU THU MAINLY IN THE AFTERNOON
SHOULD BRING MOSTLY CLOUDY SKIES FOR A FEW HOURS. -GIH
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 300 AM WEDNESDAY...
THE LONG TERM BEGINS WITH A POSITIVELY TILTED UPPER LEVEL TROUGH
EXTENDING DOWN THE EAST COAST WITH A STRONG SURFACE HIGH CENTERED
OVER THE OHIO VALLEY. THIS WILL KEEP CENTRAL NC ROOTED IN THE COLD
AIR ADVECTION REGIME WITH NORTHERLY SFC FLOW AND NWLY FLOW ALOFT.
VERY COLD AND DRY AIRMASS WITH HIGHS ONLY IN THE LOW TO MID 20S. THE
SFC HIGH DRIFTS EAST AND SETS UP OVER EASTERN NC FRIDAY NIGHT WHICH
WILL TURN WINDS AROUND TO SOUTHERLY RETURN FLOW. THIS WILL NOT BE IN
TIME TO HELP TEMPS ALL THAT MUCH AS LOWS WILL BE IN THE MID TEENS.
STILL THIS IS WARMER THAN PREVIOUS NIGHTS. BACK TO WEST...AN
INVERTED TROUGH EXTENDING INTO THE TENNESSEE VALLEY FROM A PARENT
LOW OVER NORTH TEXAS WILL BE PRODUCING AN AREA OF STRONG LOW LEVEL
CONVERGENCE AND PRECIPITATION THAT IS THE PRECURSOR TO OUR NEXT
SYSTEM. INCREASING CLOUDS CAN BE EXPECTED AHEAD OF THIS SYSTEM LATE
FRIDAY NIGHT INTO SATURDAY MORNING.
OVERALL...MODELS HAVE COME INTO BETTER AGREEMENT WITH REGARD TO THE
EVOLUTION OF THE SYSTEM APPROACHING FROM THE WEST ON SATURDAY. THERE
STILL ARE FINER DIFFERENCES THAT MAY MATTER CONSIDERABLY IN HOW THE
FINAL SCENARIO PLAYS OUT. FIRST...THE EUROPEAN HAS PICKED UP THE LOW
PRESSURE WEST OF THE MOUNTAINS THAT THE GFS WAS SHOWING YESTERDAY. A
MUCH STRONGER WAVE IN THE UPPER LEVEL PATTERN OVER TEXAS IN THE GFS
IS PRODUCING A MUCH STRONGER LOW AND IS SLOWER WITH ITS PROGRESSION
UP THE BACK OF THE COLD FRONT. THIS WILL NOT MATTER IN REGARDS TO
POTENTIAL WINTER P-TYPE ON SATURDAY AS MUCH AS IT WILL FOR THE
TIMING OF THE ADVANCEMENT OF THE COLD FRONT THROUGH THE STATE ON
SUNDAY WHICH IS FASTER IN THE ECMWF. ANOTHER COMPROMISE THE MODELS
HAVE MADE IS WITH THE IN-SITU DAMMING SCENARIO AS THE SFC HIGH MOVES
OUT TO SEA. BOTH MODELS ARE NOW PRODUCING A WEDGE FRONT BUT IT IS
MUCH WEAKER IN THE GFS THEN PRIOR RUNS AND THE HIGH PUSHES FURTHER
OUT TO SEA FASTER THAN PREVIOUS RUNS AND THUS BOTH MODELS LOSE THE
WEDGE QUICKLY LATE SATURDAY AFTERNOON/EVENING. BECAUSE OF THIS...THE
OOZ RUN OF THE GFS HAS TRENDED A BIT WARMER AS ISENTROPIC LIFT WILL
BE LESS PRONOUNCED EARLIER IN THE DAY.
THE UPSHOT IN THE FORECAST SOUNDINGS IS A REAL GRAB BAG OF POTENTIAL
PRECIPITATION TYPES FOR THE TRIAD WITH APPRECIABLE DIFFERENCES
BETWEEN THE THERMAL PROFILES EVEN BETWEEN KGSO AND KINT. THE GENERAL
TREND WILL BE A GREATER LIKELIHOOD OF SNOW NORTH AND WEST AND LESS
SO APPROACHING GREENSBORO AND POINTS SOUTH AND EAST WHERE SLEET AND
EVEN FREEZING RAIN COULD BE MORE LIKELY. VERY EARLY FOR THESE
DETAILS TO BE IRONED OUT SO WE WILL CALL IT WINTERY MIX FOR NOW.
PRECIPITATION DOES LOOK CONFINED TO THE TRIAD HOWEVER AND POINTS
EAST OF HIGHWAY 1 SHOULD REMAIN DRY FOR MUCH OF THE DAY ON SATURDAY.
HIGHS GENERALLY IN THE LOWER 40S. EXPECT A NON-DIURNAL TEMPERATURE
CURVE FOR SATURDAY NIGHT WITH TEMPERATURES BEGINNING TO WARM
CONSIDERABLY AFTER 00Z SUNDAY AS WARM AIR ADVECTION AHEAD OF THE
COLD FRONT BEGINS. LOWS IN THE MID TO UPPER 30S OCCURRING EARLY IN
THE EVENING.
RAIN ASSOCIATED WITH THE COLD FRONT WILL MOVE IN FOR SUNDAY.
CONFIDENCE IN THIS BEING ALL LIQUID IS HIGH CONSIDERING THE
OVERNIGHT RISE IN TEMPERATURES WHICH WILL CONTINUE ON SUNDAY AND THE
LOSS OF SATURATION ALOFT IN THE ICE NUCLEATION ZONE. IN
FACT...TEMPERATURES WARM SO MUCH IN THE LOW LEVELS THAT INSTABILITY
CREEPS IN BY LATE SUNDAY AFTERNOON/EARLY EVENING AND LOW AND MID
LEVEL LAPSE RATES INCREASE. RISES ARE MINIMAL BUT WOULD NOT RULE OUT
THE CHANCE FOR A HEAVY CONVECTIVE SHOWER OR ISOLATED THUNDERSTORM.
HIGHS IN THE MID TO UPPER 50S. PRECIPITATION IS EXPECTED TO END
AFTER 6Z MONDAY. TOTAL QPF AMOUNTS ARE VERY UNCERTAIN AT THIS TIME
BUT EXPECT MORE IN THE TRIAD THAN POINTS EAST. LOWS IN THE MID TO
UPPER 30S.
COLDER AND DRIER BEHIND THE FRONT WITH NORTHEASTERLY SFC FLOW ON
MONDAY WITH HIGHS IN THE MID 40S AND LOWS MONDAY NIGHT IN THE UPPER
20S. DRY FOR TUESDAY AS WELL AS LOW PRESSURE MOVES INTO THE GREAT
LAKES REGION. HIGHS IN THE MID TO UPPER 40S.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
AS OF 640 AM WEDNESDAY...
PRIMARY AVIATION CONCERNS NEXT 24 HRS: SUB-VFR CIGS/VSBYS AT FAY
EARLY THIS MORNING... A PERIOD OF MVFR CIGS AND SCATTERED SNOW
SHOWERS TODAY FROM MID AFTERNOON TO EARLY EVENING... AND
STRONG/GUSTY WINDS THIS AFTERNOON THROUGH THE END OF THE TAF VALID
PERIOD.
AN AREA OF IFR-LIFR FOG OVER THE SOUTHERN SECTIONS OF CENTRAL NC...
INCLUDING FAY... WILL DRIFT SLOWLY EASTWARD OVER THE NEXT FEW
HOURS... ACCORDING TO THE LATEST HRRR GUIDANCE. MAINLY VFR
CONDITIONS ELSEWHERE THIS MORNING... EXCEPT FOR A CLUSTER OF MVFR
CLOUDS AT GSO PRIOR TO 14Z. A CLIPPER COLD FRONT WILL SWEEP ACROSS
THE AREA THIS AFTERNOON/EARLY EVENING... AT APPROXIMATELY 18Z-20Z AT
INT/GSO... 20Z-22Z AT RDU... AND 22Z-00Z AT FAY. A SHORT PERIOD
(LIKELY AROUND 2-3 HRS AT MOST) OF MVFR CIGS/VSBYS IN SNOW SHOWERS
IS EXPECTED WITH FRONTAL PASSAGE. SURFACE WINDS FROM THE SW WILL
INCREASE IN THE FEW HOURS BEFORE FRONTAL PASSAGE... THEN REMAIN
STRONG AND GUSTY AS THEY SHIFT TO NW BEHIND THE FRONT... LASTING
THROUGH 06Z. VFR CIGS/VSBYS ARE EXPECTED AFTER FRONTAL PASSAGE.
LOOKING BEYOND 12Z THU MORNING: BRISK AND OCCASIONALLY GUSTY NW
SURFACE WINDS WILL PERSIST THROUGH THU. VFR CONDITIONS ARE EXPECTED
TO DOMINATE THROUGH FRI NIGHT WITH FRIGID HIGH PRESSURE BUILDING IN.
ANOTHER STORM SYSTEM APPROACHING FROM THE WEST AND SW WILL BRING
LIKELY SUB-VFR CONDITIONS WITH PRECIPITATION STARTING IN THE NW
EARLY SAT MORNING BEFORE SPREADING AREAWIDE SAT. SUB-VFR CONDITIONS
AND STRONG/SHIFTING WINDS WILL LAST THROUGH SUN AS A WARM FRONT
TRACKS NORTHWARD THROUGH THE REGION. -GIH
&&
.CLIMATE...
THE FOLLOWING ARE RECORD LOW AND LOW MAXIMUM TEMPERATURES FOR
FEBRUARY 19TH...AND 20TH...FOR GSO...RDU...AND FAY...
RECORD LOWS
GSO RDU FAY
FEBRUARY 19: 12 IN 1979 11 IN 1979 8 IN 1958
FEBRUARY 20: 14 IN 1934 13 IN 1979 12 IN 1958
FEBRUARY 21: 13 IN 1959 8 IN 1896 16 IN 1958
RECORD LOW MAXIMUMS
GSO RDU FAY
FEBRUARY 19: 32 IN 1958 31 IN 1903 26 IN 1979
FEBRUARY 20: 29 IN 1947 32 IN 1947 37 IN 1972
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR
NCZ007>011-021>028-038>043-073>078-083>086-088-089.
WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM EST FRIDAY
FOR NCZ007>011-021>028-038>043-073>078-083>086-088-089.
&&
$$ SYNOPSIS...BADGETT/HARTFIELD
NEAR TERM...BADGETT/HARTFIELD
SHORT TERM...HARTFIELD
LONG TERM...ELLIS
AVIATION...HARTFIELD
CLIMATE...RAH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
640 AM EST WED FEB 18 2015
.SYNOPSIS...AN ARCTIC COLD FRONT WILL CROSS THE AREA THIS AFTERNOON
THROUGH EARLY EVENING. FRIGID HIGH PRESSURE WILL BUILD OVER THE AREA
THIS EVENING THROUGH FRIDAY... BRINGING NEAR RECORD LOW TEMPERATURES
AND VERY LOW WIND CHILLS. ANOTHER STORM SYSTEM WILL APPROACH FROM
THE WEST EARLY SATURDAY.
&&
.NEAR TERM /TODAY/...
AS OF 305 AM WEDNESDAY...
...WINTER WEATHER ADVISORY FOR BLACK ICE REMAINS IN EFFECT THROUGH
10 AM THIS MORNING...
LOTS TO CONCERN OURSELVES WITH OVER THE NEXT 48 HOURS... AND BEYOND.
FIRST... AS EARLIER INDICATED BY THE HRRR AND OTHER GUIDANCE... AN
AREA OF FREEZING FOG HAS FORMED OVER THE FAR SE PIEDMONT AND INTO
THE SANDHILLS... WHERE DEWPOINTS REMAIN ELEVATED WITH CALM AIR IN
PLACE. BASED ON THE LIMITED COVERAGE AREA AND BORDERLINE
VISIBILITIES... WILL CONTINUE TO ADDRESS THIS WITH SPECIAL WEATHER
STATEMENTS AND MONITOR THE FOG... WHICH THE HRRR SHOWS HOLDING AS A
SMALL AREA WHICH DRIFTS EAST THROUGH SUNRISE. SECOND... LINGERING
WET ROADS FROM LAST NIGHT`S WINTRY WEATHER HAS REFROZEN INTO AREAS
OF BLACK ICE... DESPITE SOME SUBLIMATION ESPECIALLY IN THE NW CWA
WHERE DEWPOINTS ARE FALLING EARLY THIS MORNING. WILL LEAVE THE
WINTER WEATHER ADVISORY FOR BLACK ICE IN EFFECT FOR THE ENTIRE CWA
THROUGH 10 AM... HOWEVER BASED ON PROJECTED HOURLY TEMPS... PORTIONS
OF THE NW PIEDMONT MAY NOT SURPASS THE FREEZING MARK UNTIL CLOSER TO
11 AM OR NOON... AND THUS THE ADVISORY MAY NEED TO BE EXTENDED
FORWARD IN TIME BY AN HOUR OR TWO. FINALLY... FAIR SKIES THIS
MORNING WILL GIVE WAY TO A QUICK INCREASE IN CLOUDS BY MIDDAY... AS
THE CLIPPER FRONT AND ASSOCIATED VORTICITY MAX NOW CROSSING THE OH
VALLEY AND MIDSOUTH ARE PROJECTED TO SWING THROUGH CENTRAL NC THIS
AFTERNOON. WITH A SHOT OF LOW LEVEL MOIST UPGLIDE AT 275-280K AHEAD
OF AND WITH THE FRONT... STEEP LOW LEVEL (925-700 MB) LAPSE RATES OF
7-8 C/KM... SURFACE WET BULB TEMPS NOT MUCH ABOVE FREEZING... AND
BUFR SOUNDINGS SHOWING GOOD SATURATION FROM JUST OFF THE SURFACE UP
THROUGH THE -20C LEVEL... ALL FOCUSED ON THE 17Z-01Z TIME FRAME...
EXPECT A BRIEF WINDOW OF SNOW SHOWERS WITH THE GREATEST COVERAGE
ACROSS THE NORTH HALF... AND A LOWER RISK OF A RAIN SHOWER/SNOW
SHOWER MIX ACROSS THE SOUTH WHERE SURFACE WET BULBS SHOULD GO ABOVE
FREEZING FOR MUCH OF THE DAY. WILL STICK WITH GOOD CHANCE POPS NORTH
TAPERING TO SLIGHT CHANCE POPS SOUTH. QPF SHOULD BE QUITE LIGHT
GIVEN THE FAST MOVEMENT... BUT WITH THE STEEP LAPSE RATES SUGGESTING
A CONVECTIVE CONTRIBUTION... WE COULD SEE A SHORT PERIOD OF HEAVIER
RATES... AND WOULDN`T BE AT ALL SURPRISED TO SEE A DUSTING TO A HALF
INCH OF SNOW IN SOME SPOTS ACROSS THE NORTHERN CWA. HIGHS FROM THE
MID 30S NORTH TO LOWER 40S SOUTH. -GIH
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
AS OF 330 AM WEDNESDAY...
CONFIDENCE IN DANGEROUSLY COLD WEATHER IS INCREASING. BRISK AND
GUSTY WINDS ARE A NEAR CERTAINTY BEHIND THIS ARCTIC FRONT... WITH
THE MOMENTUM OF THE COLD DENSE AIR AND TIGHT MSLP GRADIENT. EXPECT
SUSTAINED WINDS FROM THE NW AROUND 15-25 MPH GUSTING AS HIGH AS 30-
35 MPH TONIGHT. WINDS SHOULD ABATE A BIT THU/THU NIGHT AS THE
INITIAL COLD SURGE WANES... HOWEVER THE MSLP GRADIENT REMAINS TIGHT
ENOUGH TO SUPPORT SUSTAINED NW WINDS OF AROUND 15 MPH GUSTING TO
AROUND 25 MPH THU INTO THU NIGHT. MEANWHILE... RECORD-BUSTING COLD
TEMPERATURES ARE ALSO IMMINENT... WITH MODEL THICKNESSES... BUFR
SOUNDING THERMAL STRUCTURE... STATISTICAL GUIDANCE... AND UPSTREAM
CURRENT CONDITIONS ALL SUPPORTING VERY COLD READINGS. EXPECT LOWS
TONIGHT OF 7-15... HIGHS ONLY 15-23 THU... AND LOWS THU NIGHT OF 1
BELOW TO 7 ABOVE. THESE TEMPS AND WINDS TOGETHER WILL GENERATE SOME
OF THE LOWEST WIND CHILL READINGS WE`VE SEEN IN MANY YEARS...
DROPPING BELOW 0F NEAR OR SHORTLY AFTER MIDNIGHT. WILL POST A WIND
CHILL ADVISORY FOR ALL OF CENTRAL NC STARTING AT MIDNIGHT. WHILE
WIND CHILL VALUES ARE EXPECTED TO INCH ABOVE THE 0F MARK BETWEEN
ABOUT 12 NOON AND 5 PM THU... READINGS ARE LIKELY TO DIVE DOWN WELL
BELOW ZERO ONCE AGAIN AFTER 5 PM THU... STAYING DANGEROUSLY LOW
(EVEN APPROACHING -10F) THROUGH MID MORNING FRI. SINCE THU`S TIME
FRAME OF ABOVE-ZERO WIND CHILLS WILL BE SO SHORT... AND SINCE WE`D
STILL LIKE EVERYONE TO TAKE PROPER PRECAUTIONS AND NOT BE COMPLACENT
DURING THE DAYTIME AS WIND CHILLS WILL STILL BE VERY COLD... HAVE
OPTED TO TAKE THE UNUSUAL STEP (IN THIS UNUSUAL WEATHER SITUATION)
OF EXTENDING THE WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT ALL THE
WAY THROUGH FRI MORNING. EXPECT MOSTLY CLEAR SKIES THROUGH THIS
PERIOD... ALTHOUGH FLAT BROKEN STRATOCU THU MAINLY IN THE AFTERNOON
SHOULD BRING MOSTLY CLOUDY SKIES FOR A FEW HOURS. -GIH
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 300 AM WEDNESDAY...
THE LONG TERM BEGINS WITH A POSITIVELY TILTED UPPER LEVEL TROUGH
EXTENDING DOWN THE EAST COAST WITH A STRONG SURFACE HIGH CENTERED
OVER THE OHIO VALLEY. THIS WILL KEEP CENTRAL NC ROOTED IN THE COLD
AIR ADVECTION REGIME WITH NORTHERLY SFC FLOW AND NWLY FLOW ALOFT.
VERY COLD AND DRY AIRMASS WITH HIGHS ONLY IN THE LOW TO MID 20S. THE
SFC HIGH DRIFTS EAST AND SETS UP OVER EASTERN NC FRIDAY NIGHT WHICH
WILL TURN WINDS AROUND TO SOUTHERLY RETURN FLOW. THIS WILL NOT BE IN
TIME TO HELP TEMPS ALL THAT MUCH AS LOWS WILL BE IN THE MID TEENS.
STILL THIS IS WARMER THAN PREVIOUS NIGHTS. BACK TO WEST...AN
INVERTED TROUGH EXTENDING INTO THE TENNESSEE VALLEY FROM A PARENT
LOW OVER NORTH TEXAS WILL BE PRODUCING AN AREA OF STRONG LOW LEVEL
CONVERGENCE AND PRECIPITATION THAT IS THE PRECURSOR TO OUR NEXT
SYSTEM. INCREASING CLOUDS CAN BE EXPECTED AHEAD OF THIS SYSTEM LATE
FRIDAY NIGHT INTO SATURDAY MORNING.
OVERALL...MODELS HAVE COME INTO BETTER AGREEMENT WITH REGARD TO THE
EVOLUTION OF THE SYSTEM APPROACHING FROM THE WEST ON SATURDAY. THERE
STILL ARE FINER DIFFERENCES THAT MAY MATTER CONSIDERABLY IN HOW THE
FINAL SCENARIO PLAYS OUT. FIRST...THE EUROPEAN HAS PICKED UP THE LOW
PRESSURE WEST OF THE MOUNTAINS THAT THE GFS WAS SHOWING YESTERDAY. A
MUCH STRONGER WAVE IN THE UPPER LEVEL PATTERN OVER TEXAS IN THE GFS
IS PRODUCING A MUCH STRONGER LOW AND IS SLOWER WITH ITS PROGRESSION
UP THE BACK OF THE COLD FRONT. THIS WILL NOT MATTER IN REGARDS TO
POTENTIAL WINTER P-TYPE ON SATURDAY AS MUCH AS IT WILL FOR THE
TIMING OF THE ADVANCEMENT OF THE COLD FRONT THROUGH THE STATE ON
SUNDAY WHICH IS FASTER IN THE ECMWF. ANOTHER COMPROMISE THE MODELS
HAVE MADE IS WITH THE IN-SITU DAMMING SCENARIO AS THE SFC HIGH MOVES
OUT TO SEA. BOTH MODELS ARE NOW PRODUCING A WEDGE FRONT BUT IT IS
MUCH WEAKER IN THE GFS THEN PRIOR RUNS AND THE HIGH PUSHES FURTHER
OUT TO SEA FASTER THAN PREVIOUS RUNS AND THUS BOTH MODELS LOSE THE
WEDGE QUICKLY LATE SATURDAY AFTERNOON/EVENING. BECAUSE OF THIS...THE
OOZ RUN OF THE GFS HAS TRENDED A BIT WARMER AS ISENTROPIC LIFT WILL
BE LESS PRONOUNCED EARLIER IN THE DAY.
THE UPSHOT IN THE FORECAST SOUNDINGS IS A REAL GRAB BAG OF POTENTIAL
PRECIPITATION TYPES FOR THE TRIAD WITH APPRECIABLE DIFFERENCES
BETWEEN THE THERMAL PROFILES EVEN BETWEEN KGSO AND KINT. THE GENERAL
TREND WILL BE A GREATER LIKELIHOOD OF SNOW NORTH AND WEST AND LESS
SO APPROACHING GREENSBORO AND POINTS SOUTH AND EAST WHERE SLEET AND
EVEN FREEZING RAIN COULD BE MORE LIKELY. VERY EARLY FOR THESE
DETAILS TO BE IRONED OUT SO WE WILL CALL IT WINTERY MIX FOR NOW.
PRECIPITATION DOES LOOK CONFINED TO THE TRIAD HOWEVER AND POINTS
EAST OF HIGHWAY 1 SHOULD REMAIN DRY FOR MUCH OF THE DAY ON SATURDAY.
HIGHS GENERALLY IN THE LOWER 40S. EXPECT A NON-DIURNAL TEMPERATURE
CURVE FOR SATURDAY NIGHT WITH TEMPERATURES BEGINNING TO WARM
CONSIDERABLY AFTER 00Z SUNDAY AS WARM AIR ADVECTION AHEAD OF THE
COLD FRONT BEGINS. LOWS IN THE MID TO UPPER 30S OCCURRING EARLY IN
THE EVENING.
RAIN ASSOCIATED WITH THE COLD FRONT WILL MOVE IN FOR SUNDAY.
CONFIDENCE IN THIS BEING ALL LIQUID IS HIGH CONSIDERING THE
OVERNIGHT RISE IN TEMPERATURES WHICH WILL CONTINUE ON SUNDAY AND THE
LOSS OF SATURATION ALOFT IN THE ICE NUCLEATION ZONE. IN
FACT...TEMPERATURES WARM SO MUCH IN THE LOW LEVELS THAT INSTABILITY
CREEPS IN BY LATE SUNDAY AFTERNOON/EARLY EVENING AND LOW AND MID
LEVEL LAPSE RATES INCREASE. RISES ARE MINIMAL BUT WOULD NOT RULE OUT
THE CHANCE FOR A HEAVY CONVECTIVE SHOWER OR ISOLATED THUNDERSTORM.
HIGHS IN THE MID TO UPPER 50S. PRECIPITATION IS EXPECTED TO END
AFTER 6Z MONDAY. TOTAL QPF AMOUNTS ARE VERY UNCERTAIN AT THIS TIME
BUT EXPECT MORE IN THE TRIAD THAN POINTS EAST. LOWS IN THE MID TO
UPPER 30S.
COLDER AND DRIER BEHIND THE FRONT WITH NORTHEASTERLY SFC FLOW ON
MONDAY WITH HIGHS IN THE MID 40S AND LOWS MONDAY NIGHT IN THE UPPER
20S. DRY FOR TUESDAY AS WELL AS LOW PRESSURE MOVES INTO THE GREAT
LAKES REGION. HIGHS IN THE MID TO UPPER 40S.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
AS OF 640 AM WEDNESDAY...
PRIMARY AVIATION CONCERNS NEXT 24 HRS: SUB-VFR CIGS/VSBYS AT FAY
EARLY THIS MORNING... A PERIOD OF MVFR CIGS AND SCATTERED SNOW
SHOWERS TODAY FROM MID AFTERNOON TO EARLY EVENING... AND
STRONG/GUSTY WINDS THIS AFTERNOON THROUGH THE END OF THE TAF VALID
PERIOD.
AN AREA OF IFR-LIFR FOG OVER THE SOUTHERN SECTIONS OF CENTRAL NC...
INCLUDING FAY... WILL DRIFT SLOWLY EASTWARD OVER THE NEXT FEW
HOURS... ACCORDING TO THE LATEST HRRR GUIDANCE. MAINLY VFR
CONDITIONS ELSEWHERE THIS MORNING... EXCEPT FOR A CLUSTER OF MVFR
CLOUDS AT GSO PRIOR TO 14Z. A CLIPPER COLD FRONT WILL SWEEP ACROSS
THE AREA THIS AFTERNOON/EARLY EVENING... AT APPROXIMATELY 18Z-20Z AT
INT/GSO... 20Z-22Z AT RDU... AND 22Z-00Z AT FAY. A SHORT PERIOD
(LIKELY AROUND 2-3 HRS AT MOST) OF MVFR CIGS/VSBYS IN SNOW SHOWERS
IS EXPECTED WITH FRONTAL PASSAGE. SURFACE WINDS FROM THE SW WILL
INCREASE IN THE FEW HOURS BEFORE FRONTAL PASSAGE... THEN REMAIN
STRONG AND GUSTY AS THEY SHIFT TO NW BEHIND THE FRONT... LASTING
THROUGH 06Z. VFR CIGS/VSBYS ARE EXPECTED AFTER FRONTAL PASSAGE.
LOOKING BEYOND 12Z THU MORNING: BRISK AND OCCASIONALLY GUSTY NW
SURFACE WINDS WILL PERSIST THROUGH THU. VFR CONDITIONS ARE EXPECTED
TO DOMINATE THROUGH FRI NIGHT WITH FRIGID HIGH PRESSURE BUILDING IN.
ANOTHER STORM SYSTEM APPROACHING FROM THE WEST AND SW WILL BRING
LIKELY SUB-VFR CONDITIONS WITH PRECIPITATION STARTING IN THE NW
EARLY SAT MORNING BEFORE SPREADING AREAWIDE SAT. SUB-VFR CONDITIONS
AND STRONG/SHIFTING WINDS WILL LAST THROUGH SUN AS A WARM FRONT
TRACKS NORTHWARD THROUGH THE REGION. -GIH
&&
.CLIMATE...
THE FOLLOWING ARE RECORD LOW AND LOW MAXIMUM TEMPERATURES FOR
FEBRUARY 19TH...AND 20TH...FOR GSO...RDU...AND FAY...
RECORD LOWS
GSO RDU FAY
FEBRUARY 19: 12 IN 1979 11 IN 1979 8 IN 1958
FEBRUARY 20: 14 IN 1934 13 IN 1979 12 IN 1958
FEBRUARY 21: 13 IN 1959 8 IN 1896 16 IN 1958
RECORD LOW MAXIMUMS
GSO RDU FAY
FEBRUARY 19: 32 IN 1958 31 IN 1903 26 IN 1979
FEBRUARY 20: 29 IN 1947 32 IN 1947 37 IN 1972
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR
NCZ007>011-021>028-038>043-073>078-083>086-088-089.
WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM EST FRIDAY
FOR NCZ007>011-021>028-038>043-073>078-083>086-088-089.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...HARTFIELD
SHORT TERM...HARTFIELD
LONG TERM...ELLIS
AVIATION...HARTFIELD
CLIMATE...RAH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
330 AM EST WED FEB 18 2015
.SYNOPSIS...AN ARCTIC COLD FRONT WILL CROSS THE AREA THIS AFTERNOON
THROUGH EARLY EVENING. FRIGID HIGH PRESSURE WILL BUILD OVER THE AREA
THIS EVENING THROUGH FRIDAY... BRINGING NEAR RECORD LOW TEMPERATURES
AND VERY LOW WIND CHILLS. ANOTHER STORM SYSTEM WILL APPROACH FROM
THE WEST EARLY SATURDAY.
&&
.NEAR TERM /TODAY/...
AS OF 305 AM WEDNESDAY...
...WINTER WEATHER ADVISORY FOR BLACK ICE REMAINS IN EFFECT THROUGH
10 AM THIS MORNING...
LOTS TO CONCERN OURSELVES WITH OVER THE NEXT 48 HOURS... AND BEYOND.
FIRST... AS EARLIER INDICATED BY THE HRRR AND OTHER GUIDANCE... AN
AREA OF FREEZING FOG HAS FORMED OVER THE FAR SE PIEDMONT AND INTO
THE SANDHILLS... WHERE DEWPOINTS REMAIN ELEVATED WITH CALM AIR IN
PLACE. BASED ON THE LIMITED COVERAGE AREA AND BORDERLINE
VISIBILITIES... WILL CONTINUE TO ADDRESS THIS WITH SPECIAL WEATHER
STATEMENTS AND MONITOR THE FOG... WHICH THE HRRR SHOWS HOLDING AS A
SMALL AREA WHICH DRIFTS EAST THROUGH SUNRISE. SECOND... LINGERING
WET ROADS FROM LAST NIGHT`S WINTRY WEATHER HAS REFROZEN INTO AREAS
OF BLACK ICE... DESPITE SOME SUBLIMATION ESPECIALLY IN THE NW CWA
WHERE DEWPOINTS ARE FALLING EARLY THIS MORNING. WILL LEAVE THE
WINTER WEATHER ADVISORY FOR BLACK ICE IN EFFECT FOR THE ENTIRE CWA
THROUGH 10 AM... HOWEVER BASED ON PROJECTED HOURLY TEMPS... PORTIONS
OF THE NW PIEDMONT MAY NOT SURPASS THE FREEZING MARK UNTIL CLOSER TO
11 AM OR NOON... AND THUS THE ADVISORY MAY NEED TO BE EXTENDED
FORWARD IN TIME BY AN HOUR OR TWO. FINALLY... FAIR SKIES THIS
MORNING WILL GIVE WAY TO A QUICK INCREASE IN CLOUDS BY MIDDAY... AS
THE CLIPPER FRONT AND ASSOCIATED VORTICITY MAX NOW CROSSING THE OH
VALLEY AND MIDSOUTH ARE PROJECTED TO SWING THROUGH CENTRAL NC THIS
AFTERNOON. WITH A SHOT OF LOW LEVEL MOIST UPGLIDE AT 275-280K AHEAD
OF AND WITH THE FRONT... STEEP LOW LEVEL (925-700 MB) LAPSE RATES OF
7-8 C/KM... SURFACE WET BULB TEMPS NOT MUCH ABOVE FREEZING... AND
BUFR SOUNDINGS SHOWING GOOD SATURATION FROM JUST OFF THE SURFACE UP
THROUGH THE -20C LEVEL... ALL FOCUSED ON THE 17Z-01Z TIME FRAME...
EXPECT A BRIEF WINDOW OF SNOW SHOWERS WITH THE GREATEST COVERAGE
ACROSS THE NORTH HALF... AND A LOWER RISK OF A RAIN SHOWER/SNOW
SHOWER MIX ACROSS THE SOUTH WHERE SURFACE WET BULBS SHOULD GO ABOVE
FREEZING FOR MUCH OF THE DAY. WILL STICK WITH GOOD CHANCE POPS NORTH
TAPERING TO SLIGHT CHANCE POPS SOUTH. QPF SHOULD BE QUITE LIGHT
GIVEN THE FAST MOVEMENT... BUT WITH THE STEEP LAPSE RATES SUGGESTING
A CONVECTIVE CONTRIBUTION... WE COULD SEE A SHORT PERIOD OF HEAVIER
RATES... AND WOULDN`T BE AT ALL SURPRISED TO SEE A DUSTING TO A HALF
INCH OF SNOW IN SOME SPOTS ACROSS THE NORTHERN CWA. HIGHS FROM THE
MID 30S NORTH TO LOWER 40S SOUTH. -GIH
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
AS OF 330 AM WEDNESDAY...
CONFIDENCE IN DANGEROUSLY COLD WEATHER IS INCREASING. BRISK AND
GUSTY WINDS ARE A NEAR CERTAINTY BEHIND THIS ARCTIC FRONT... WITH
THE MOMENTUM OF THE COLD DENSE AIR AND TIGHT MSLP GRADIENT. EXPECT
SUSTAINED WINDS FROM THE NW AROUND 15-25 MPH GUSTING AS HIGH AS 30-
35 MPH TONIGHT. WINDS SHOULD ABATE A BIT THU/THU NIGHT AS THE
INITIAL COLD SURGE WANES... HOWEVER THE MSLP GRADIENT REMAINS TIGHT
ENOUGH TO SUPPORT SUSTAINED NW WINDS OF AROUND 15 MPH GUSTING TO
AROUND 25 MPH THU INTO THU NIGHT. MEANWHILE... RECORD-BUSTING COLD
TEMPERATURES ARE ALSO IMMINENT... WITH MODEL THICKNESSES... BUFR
SOUNDING THERMAL STRUCTURE... STATISTICAL GUIDANCE... AND UPSTREAM
CURRENT CONDITIONS ALL SUPPORTING VERY COLD READINGS. EXPECT LOWS
TONIGHT OF 7-15... HIGHS ONLY 15-23 THU... AND LOWS THU NIGHT OF 1
BELOW TO 7 ABOVE. THESE TEMPS AND WINDS TOGETHER WILL GENERATE SOME
OF THE LOWEST WIND CHILL READINGS WE`VE SEEN IN MANY YEARS...
DROPPING BELOW 0F NEAR OR SHORTLY AFTER MIDNIGHT. WILL POST A WIND
CHILL ADVISORY FOR ALL OF CENTRAL NC STARTING AT MIDNIGHT. WHILE
WIND CHILL VALUES ARE EXPECTED TO INCH ABOVE THE 0F MARK BETWEEN
ABOUT 12 NOON AND 5 PM THU... READINGS ARE LIKELY TO DIVE DOWN WELL
BELOW ZERO ONCE AGAIN AFTER 5 PM THU... STAYING DANGEROUSLY LOW
(EVEN APPROACHING -10F) THROUGH MID MORNING FRI. SINCE THU`S TIME
FRAME OF ABOVE-ZERO WIND CHILLS WILL BE SO SHORT... AND SINCE WE`D
STILL LIKE EVERYONE TO TAKE PROPER PRECAUTIONS AND NOT BE COMPLACENT
DURING THE DAYTIME AS WIND CHILLS WILL STILL BE VERY COLD... HAVE
OPTED TO TAKE THE UNUSUAL STEP (IN THIS UNUSUAL WEATHER SITUATION)
OF EXTENDING THE WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT ALL THE
WAY THROUGH FRI MORNING. EXPECT MOSTLY CLEAR SKIES THROUGH THIS
PERIOD... ALTHOUGH FLAT BROKEN STRATOCU THU MAINLY IN THE AFTERNOON
SHOULD BRING MOSTLY CLOUDY SKIES FOR A FEW HOURS. -GIH
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 300 AM WEDNESDAY...
THE LONG TERM BEGINS WITH A POSITIVELY TILTED UPPER LEVEL TROUGH
EXTENDING DOWN THE EAST COAST WITH A STRONG SURFACE HIGH CENTERED
OVER THE OHIO VALLEY. THIS WILL KEEP CENTRAL NC ROOTED IN THE COLD
AIR ADVECTION REGIME WITH NORTHERLY SFC FLOW AND NWLY FLOW ALOFT.
VERY COLD AND DRY AIRMASS WITH HIGHS ONLY IN THE LOW TO MID 20S. THE
SFC HIGH DRIFTS EAST AND SETS UP OVER EASTERN NC FRIDAY NIGHT WHICH
WILL TURN WINDS AROUND TO SOUTHERLY RETURN FLOW. THIS WILL NOT BE IN
TIME TO HELP TEMPS ALL THAT MUCH AS LOWS WILL BE IN THE MID TEENS.
STILL THIS IS WARMER THAN PREVIOUS NIGHTS. BACK TO WEST...AN
INVERTED TROUGH EXTENDING INTO THE TENNESSEE VALLEY FROM A PARENT
LOW OVER NORTH TEXAS WILL BE PRODUCING AN AREA OF STRONG LOW LEVEL
CONVERGENCE AND PRECIPITATION THAT IS THE PRECURSOR TO OUR NEXT
SYSTEM. INCREASING CLOUDS CAN BE EXPECTED AHEAD OF THIS SYSTEM LATE
FRIDAY NIGHT INTO SATURDAY MORNING.
OVERALL...MODELS HAVE COME INTO BETTER AGREEMENT WITH REGARD TO THE
EVOLUTION OF THE SYSTEM APPROACHING FROM THE WEST ON SATURDAY. THERE
STILL ARE FINER DIFFERENCES THAT MAY MATTER CONSIDERABLY IN HOW THE
FINAL SCENARIO PLAYS OUT. FIRST...THE EUROPEAN HAS PICKED UP THE LOW
PRESSURE WEST OF THE MOUNTAINS THAT THE GFS WAS SHOWING YESTERDAY. A
MUCH STRONGER WAVE IN THE UPPER LEVEL PATTERN OVER TEXAS IN THE GFS
IS PRODUCING A MUCH STRONGER LOW AND IS SLOWER WITH ITS PROGRESSION
UP THE BACK OF THE COLD FRONT. THIS WILL NOT MATTER IN REGARDS TO
POTENTIAL WINTER P-TYPE ON SATURDAY AS MUCH AS IT WILL FOR THE
TIMING OF THE ADVANCEMENT OF THE COLD FRONT THROUGH THE STATE ON
SUNDAY WHICH IS FASTER IN THE ECMWF. ANOTHER COMPROMISE THE MODELS
HAVE MADE IS WITH THE IN-SITU DAMMING SCENARIO AS THE SFC HIGH MOVES
OUT TO SEA. BOTH MODELS ARE NOW PRODUCING A WEDGE FRONT BUT IT IS
MUCH WEAKER IN THE GFS THEN PRIOR RUNS AND THE HIGH PUSHES FURTHER
OUT TO SEA FASTER THAN PREVIOUS RUNS AND THUS BOTH MODELS LOSE THE
WEDGE QUICKLY LATE SATURDAY AFTERNOON/EVENING. BECAUSE OF THIS...THE
OOZ RUN OF THE GFS HAS TRENDED A BIT WARMER AS ISENTROPIC LIFT WILL
BE LESS PRONOUNCED EARLIER IN THE DAY.
THE UPSHOT IN THE FORECAST SOUNDINGS IS A REAL GRAB BAG OF POTENTIAL
PRECIPITATION TYPES FOR THE TRIAD WITH APPRECIABLE DIFFERENCES
BETWEEN THE THERMAL PROFILES EVEN BETWEEN KGSO AND KINT. THE GENERAL
TREND WILL BE A GREATER LIKELIHOOD OF SNOW NORTH AND WEST AND LESS
SO APPROACHING GREENSBORO AND POINTS SOUTH AND EAST WHERE SLEET AND
EVEN FREEZING RAIN COULD BE MORE LIKELY. VERY EARLY FOR THESE
DETAILS TO BE IRONED OUT SO WE WILL CALL IT WINTERY MIX FOR NOW.
PRECIPITATION DOES LOOK CONFINED TO THE TRIAD HOWEVER AND POINTS
EAST OF HIGHWAY 1 SHOULD REMAIN DRY FOR MUCH OF THE DAY ON SATURDAY.
HIGHS GENERALLY IN THE LOWER 40S. EXPECT A NON-DIURNAL TEMPERATURE
CURVE FOR SATURDAY NIGHT WITH TEMPERATURES BEGINNING TO WARM
CONSIDERABLY AFTER 00Z SUNDAY AS WARM AIR ADVECTION AHEAD OF THE
COLD FRONT BEGINS. LOWS IN THE MID TO UPPER 30S OCCURRING EARLY IN
THE EVENING.
RAIN ASSOCIATED WITH THE COLD FRONT WILL MOVE IN FOR SUNDAY.
CONFIDENCE IN THIS BEING ALL LIQUID IS HIGH CONSIDERING THE
OVERNIGHT RISE IN TEMPERATURES WHICH WILL CONTINUE ON SUNDAY AND THE
LOSS OF SATURATION ALOFT IN THE ICE NUCLEATION ZONE. IN
FACT...TEMPERATURES WARM SO MUCH IN THE LOW LEVELS THAT INSTABILITY
CREEPS IN BY LATE SUNDAY AFTERNOON/EARLY EVENING AND LOW AND MID
LEVEL LAPSE RATES INCREASE. RISES ARE MINIMAL BUT WOULD NOT RULE OUT
THE CHANCE FOR A HEAVY CONVECTIVE SHOWER OR ISOLATED THUNDERSTORM.
HIGHS IN THE MID TO UPPER 50S. PRECIPITATION IS EXPECTED TO END
AFTER 6Z MONDAY. TOTAL QPF AMOUNTS ARE VERY UNCERTAIN AT THIS TIME
BUT EXPECT MORE IN THE TRIAD THAN POINTS EAST. LOWS IN THE MID TO
UPPER 30S.
COLDER AND DRIER BEHIND THE FRONT WITH NORTHEASTERLY SFC FLOW ON
MONDAY WITH HIGHS IN THE MID 40S AND LOWS MONDAY NIGHT IN THE UPPER
20S. DRY FOR TUESDAY AS WELL AS LOW PRESSURE MOVES INTO THE GREAT
LAKES REGION. HIGHS IN THE MID TO UPPER 40S.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
AS OF 1235 AM WEDNESDAY...
PRIMARY AVIATION CONCERNS NEXT 24 HRS: SUB-VFR CIGS/VSBYS AT FAY
EARLY THIS MORNING (BEFORE DAYBREAK)... A PERIOD OF MVFR CIGS AND
SCATTERED SNOW SHOWERS TODAY FROM MID AFTERNOON TO EARLY EVENING...
AND STRONG/GUSTY WINDS THIS AFTERNOON THROUGH THE END OF THE TAF
VALID PERIOD.
AREAS OF MVFR FOG HAVE DEVELOPED OVER THE SOUTHERN SECTIONS OF
CENTRAL NC IN THE LAST FEW HOURS. LATEST GUIDANCE SUPPORTS A PERIOD
OF IFR/LIFR FOG AT FAY EARLY THIS MORNING. VFR CONDITIONS ELSEWHERE
THIS MORNING. A CLIPPER COLD FRONT WILL SWEEP ACROSS THE AREA THIS
AFTERNOON/EARLY EVENING... AT APPROXIMATELY 18Z-20Z AT INT/GSO...
20Z-22Z AT RDU... AND 22Z-00Z AT FAY. A SHORT PERIOD (LIKELY AROUND
2-3 HRS AT MOST) OF MVFR CIGS/VSBYS IN SNOW SHOWERS IS EXPECTED WITH
FRONTAL PASSAGE. SURFACE WINDS FROM THE SW WILL INCREASE IN THE FEW
HOURS BEFORE FRONTAL PASSAGE... THEN REMAIN STRONG AND GUSTY AS THEY
SHIFT TO NW BEHIND THE FRONT... LASTING THROUGH 06Z. VFR CIGS/VSBYS
ARE EXPECTED AFTER FRONTAL PASSAGE.
LOOKING BEYOND 06Z EARLY THU MORNING: BRISK AND OCCASIONALLY GUSTY
NW SURFACE WINDS WILL PERSIST THROUGH THU. VFR CONDITIONS ARE
EXPECTED TO DOMINATE THROUGH FRI NIGHT WITH FRIGID HIGH PRESSURE
BUILDING IN. ANOTHER STORM SYSTEM APPROACHING FROM THE WEST AND SW
WILL BRING LIKELY SUB-VFR CONDITIONS WITH PRECIPITATION STARTING IN
THE NW EARLY SAT MORNING BEFORE SPREADING AREAWIDE SAT. SUB-VFR
CONDITIONS AND STRONG/SHIFTING WINDS WILL LAST THROUGH SUN AS A WARM
FRONT TRACKS NORTHWARD THROUGH THE REGION. -GIH
&&
.CLIMATE...
THE FOLLOWING ARE RECORD LOW AND LOW MAXIMUM TEMPERATURES FOR
FEBRUARY 19TH...AND 20TH...FOR GSO...RDU...AND FAY...
RECORD LOWS
GSO RDU FAY
FEBRUARY 19: 12 IN 1979 11 IN 1979 8 IN 1958
FEBRUARY 20: 14 IN 1934 13 IN 1979 12 IN 1958
FEBRUARY 21: 13 IN 1959 8 IN 1896 16 IN 1958
RECORD LOW MAXIMUMS
GSO RDU FAY
FEBRUARY 19: 32 IN 1958 31 IN 1903 26 IN 1979
FEBRUARY 20: 29 IN 1947 32 IN 1947 37 IN 1972
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR
NCZ007>011-021>028-038>043-073>078-083>086-088-089.
WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM EST FRIDAY
FOR NCZ007>011-021>028-038>043-073>078-083>086-088-089.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...HARTFIELD
SHORT TERM...HARTFIELD
LONG TERM...ELLIS
AVIATION...HARTFIELD
CLIMATE...RAH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
305 AM EST WED FEB 18 2015
.SYNOPSIS...AN ARCTIC COLD FRONT WILL CROSS THE AREA THIS AFTERNOON
THROUGH EARLY EVENING. FRIGID HIGH PRESSURE WILL BUILD OVER THE AREA
THIS EVENING THROUGH FRIDAY... BRINGING NEAR RECORD LOW TEMPERATURES
AND VERY LOW WIND CHILLS. ANOTHER STORM SYSTEM WILL APPROACH FROM
THE WEST EARLY SATURDAY.
&&
.NEAR TERM /TODAY/...
AS OF 305 AM WEDNESDAY...
...WINTER WEATHER ADVISORY FOR BLACK ICE REMAINS IN EFFECT THROUGH
10 AM THIS MORNING...
LOTS TO CONCERN OURSELVES WITH OVER THE NEXT 48 HOURS... AND BEYOND.
FIRST... AS EARLIER INDICATED BY THE HRRR AND OTHER GUIDANCE... AN
AREA OF FREEZING FOG HAS FORMED OVER THE FAR SE PIEDMONT AND INTO
THE SANDHILLS... WHERE DEWPOINTS REMAIN ELEVATED WITH CALM AIR IN
PLACE. BASED ON THE LIMITED COVERAGE AREA AND BORDERLINE
VISIBILITIES... WILL CONTINUE TO ADDRESS THIS WITH SPECIAL WEATHER
STATEMENTS AND MONITOR THE FOG... WHICH THE HRRR SHOWS HOLDING AS A
SMALL AREA WHICH DRIFTS EAST THROUGH SUNRISE. SECOND... LINGERING
WET ROADS FROM LAST NIGHT`S WINTRY WEATHER HAS REFROZEN INTO AREAS
OF BLACK ICE... DESPITE SOME SUBLIMATION ESPECIALLY IN THE NW CWA
WHERE DEWPOINTS ARE FALLING EARLY THIS MORNING. WILL LEAVE THE
WINTER WEATHER ADVISORY FOR BLACK ICE IN EFFECT FOR THE ENTIRE CWA
THROUGH 10 AM... HOWEVER BASED ON PROJECTED HOURLY TEMPS... PORTIONS
OF THE NW PIEDMONT MAY NOT SURPASS THE FREEZING MARK UNTIL CLOSER TO
11 AM OR NOON... AND THUS THE ADVISORY MAY NEED TO BE EXTENDED
FORWARD IN TIME BY AN HOUR OR TWO. FINALLY... FAIR SKIES THIS
MORNING WILL GIVE WAY TO A QUICK INCREASE IN CLOUDS BY MIDDAY... AS
THE CLIPPER FRONT AND ASSOCIATED VORTICITY MAX NOW CROSSING THE OH
VALLEY AND MIDSOUTH ARE PROJECTED TO SWING THROUGH CENTRAL NC THIS
AFTERNOON. WITH A SHOT OF LOW LEVEL MOIST UPGLIDE AT 275-280K AHEAD
OF AND WITH THE FRONT... STEEP LOW LEVEL (925-700 MB) LAPSE RATES OF
7-8 C/KM... SURFACE WET BULB TEMPS NOT MUCH ABOVE FREEZING... AND
BUFR SOUNDINGS SHOWING GOOD SATURATION FROM JUST OFF THE SURFACE UP
THROUGH THE -20C LEVEL... ALL FOCUSED ON THE 17Z-01Z TIME FRAME...
EXPECT A BRIEF WINDOW OF SNOW SHOWERS WITH THE GREATEST COVERAGE
ACROSS THE NORTH HALF... AND A LOWER RISK OF A RAIN SHOWER/SNOW
SHOWER MIX ACROSS THE SOUTH WHERE SURFACE WET BULBS SHOULD GO ABOVE
FREEZING FOR MUCH OF THE DAY. WILL STICK WITH GOOD CHANCE POPS NORTH
TAPERING TO SLIGHT CHANCE POPS SOUTH. QPF SHOULD BE QUITE LIGHT
GIVEN THE FAST MOVEMENT... BUT WITH THE STEEP LAPSE RATES SUGGESTING
A CONVECTIVE CONTRIBUTION... WE COULD SEE A SHORT PERIOD OF HEAVIER
RATES... AND WOULDN`T BE AT ALL SURPRISED TO SEE A DUSTING TO A HALF
INCH OF SNOW IN SOME SPOTS ACROSS THE NORTHERN CWA. HIGHS FROM THE
MID 30S NORTH TO LOWER 40S SOUTH. -GIH
&&
.SHORT TERM /WEDNESDAY NIGHT/...
AS OF 337 PM TUESDAY...
PREPARE FOR DANGEROUS LIFE THREATENING COLD.
NW WINDS 15-25 MPH WILL GUST TO 35-40 MPH WEDNESDAY NIGHT WITH
RAPIDLY CLEARING EXPECTED. VERY INTENSE COLD AIR ADVECTION WILL
LEAD TO LOWS OF 5-15 NW TO SE BY THURSDAY MORNING.
WIND CHILL ADVISORIES WILL LIKELY BE NEEDED WEDNESDAY NIGHT AND
THURSDAY WHEN WIND CHILL INDICES SHOULD RANGE BETWEEN ZERO AND 15
BELOW ZERO.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 300 AM WEDNESDAY...
THE LONG TERM BEGINS WITH A POSITIVELY TILTED UPPER LEVEL TROUGH
EXTENDING DOWN THE EAST COAST WITH A STRONG SURFACE HIGH CENTERED
OVER THE OHIO VALLEY. THIS WILL KEEP CENTRAL NC ROOTED IN THE COLD
AIR ADVECTION REGIME WITH NORTHERLY SFC FLOW AND NWLY FLOW ALOFT.
VERY COLD AND DRY AIRMASS WITH HIGHS ONLY IN THE LOW TO MID 20S. THE
SFC HIGH DRIFTS EAST AND SETS UP OVER EASTERN NC FRIDAY NIGHT WHICH
WILL TURN WINDS AROUND TO SOUTHERLY RETURN FLOW. THIS WILL NOT BE IN
TIME TO HELP TEMPS ALL THAT MUCH AS LOWS WILL BE IN THE MID TEENS.
STILL THIS IS WARMER THAN PREVIOUS NIGHTS. BACK TO WEST...AN
INVERTED TROUGH EXTENDING INTO THE TENNESSEE VALLEY FROM A PARENT
LOW OVER NORTH TEXAS WILL BE PRODUCING AN AREA OF STRONG LOW LEVEL
CONVERGENCE AND PRECIPITATION THAT IS THE PRECURSOR TO OUR NEXT
SYSTEM. INCREASING CLOUDS CAN BE EXPECTED AHEAD OF THIS SYSTEM LATE
FRIDAY NIGHT INTO SATURDAY MORNING.
OVERALL...MODELS HAVE COME INTO BETTER AGREEMENT WITH REGARD TO THE
EVOLUTION OF THE SYSTEM APPROACHING FROM THE WEST ON SATURDAY. THERE
STILL ARE FINER DIFFERENCES THAT MAY MATTER CONSIDERABLY IN HOW THE
FINAL SCENARIO PLAYS OUT. FIRST...THE EUROPEAN HAS PICKED UP THE LOW
PRESSURE WEST OF THE MOUNTAINS THAT THE GFS WAS SHOWING YESTERDAY. A
MUCH STRONGER WAVE IN THE UPPER LEVEL PATTERN OVER TEXAS IN THE GFS
IS PRODUCING A MUCH STRONGER LOW AND IS SLOWER WITH ITS PROGRESSION
UP THE BACK OF THE COLD FRONT. THIS WILL NOT MATTER IN REGARDS TO
POTENTIAL WINTER P-TYPE ON SATURDAY AS MUCH AS IT WILL FOR THE
TIMING OF THE ADVANCEMENT OF THE COLD FRONT THROUGH THE STATE ON
SUNDAY WHICH IS FASTER IN THE ECMWF. ANOTHER COMPROMISE THE MODELS
HAVE MADE IS WITH THE IN-SITU DAMMING SCENARIO AS THE SFC HIGH MOVES
OUT TO SEA. BOTH MODELS ARE NOW PRODUCING A WEDGE FRONT BUT IT IS
MUCH WEAKER IN THE GFS THEN PRIOR RUNS AND THE HIGH PUSHES FURTHER
OUT TO SEA FASTER THAN PREVIOUS RUNS AND THUS BOTH MODELS LOSE THE
WEDGE QUICKLY LATE SATURDAY AFTERNOON/EVENING. BECAUSE OF THIS...THE
OOZ RUN OF THE GFS HAS TRENDED A BIT WARMER AS ISENTROPIC LIFT WILL
BE LESS PRONOUNCED EARLIER IN THE DAY.
THE UPSHOT IN THE FORECAST SOUNDINGS IS A REAL GRAB BAG OF POTENTIAL
PRECIPITATION TYPES FOR THE TRIAD WITH APPRECIABLE DIFFERENCES
BETWEEN THE THERMAL PROFILES EVEN BETWEEN KGSO AND KINT. THE GENERAL
TREND WILL BE A GREATER LIKELIHOOD OF SNOW NORTH AND WEST AND LESS
SO APPROACHING GREENSBORO AND POINTS SOUTH AND EAST WHERE SLEET AND
EVEN FREEZING RAIN COULD BE MORE LIKELY. VERY EARLY FOR THESE
DETAILS TO BE IRONED OUT SO WE WILL CALL IT WINTERY MIX FOR NOW.
PRECIPITATION DOES LOOK CONFINED TO THE TRIAD HOWEVER AND POINTS
EAST OF HIGHWAY 1 SHOULD REMAIN DRY FOR MUCH OF THE DAY ON SATURDAY.
HIGHS GENERALLY IN THE LOWER 40S. EXPECT A NON-DIURNAL TEMPERATURE
CURVE FOR SATURDAY NIGHT WITH TEMPERATURES BEGINNING TO WARM
CONSIDERABLY AFTER 00Z SUNDAY AS WARM AIR ADVECTION AHEAD OF THE
COLD FRONT BEGINS. LOWS IN THE MID TO UPPER 30S OCCURRING EARLY IN
THE EVENING.
RAIN ASSOCIATED WITH THE COLD FRONT WILL MOVE IN FOR SUNDAY.
CONFIDENCE IN THIS BEING ALL LIQUID IS HIGH CONSIDERING THE
OVERNIGHT RISE IN TEMPERATURES WHICH WILL CONTINUE ON SUNDAY AND THE
LOSS OF SATURATION ALOFT IN THE ICE NUCLEATION ZONE. IN
FACT...TEMPERATURES WARM SO MUCH IN THE LOW LEVELS THAT INSTABILITY
CREEPS IN BY LATE SUNDAY AFTERNOON/EARLY EVENING AND LOW AND MID
LEVEL LAPSE RATES INCREASE. RISES ARE MINIMAL BUT WOULD NOT RULE OUT
THE CHANCE FOR A HEAVY CONVECTIVE SHOWER OR ISOLATED THUNDERSTORM.
HIGHS IN THE MID TO UPPER 50S. PRECIPITATION IS EXPECTED TO END
AFTER 6Z MONDAY. TOTAL QPF AMOUNTS ARE VERY UNCERTAIN AT THIS TIME
BUT EXPECT MORE IN THE TRIAD THAN POINTS EAST. LOWS IN THE MID TO
UPPER 30S.
COLDER AND DRIER BEHIND THE FRONT WITH NORTHEASTERLY SFC FLOW ON
MONDAY WITH HIGHS IN THE MID 40S AND LOWS MONDAY NIGHT IN THE UPPER
20S. DRY FOR TUESDAY AS WELL AS LOW PRESSURE MOVES INTO THE GREAT
LAKES REGION. HIGHS IN THE MID TO UPPER 40S.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
AS OF 1235 AM WEDNESDAY...
PRIMARY AVIATION CONCERNS NEXT 24 HRS: SUB-VFR CIGS/VSBYS AT FAY
EARLY THIS MORNING (BEFORE DAYBREAK)... A PERIOD OF MVFR CIGS AND
SCATTERED SNOW SHOWERS TODAY FROM MID AFTERNOON TO EARLY EVENING...
AND STRONG/GUSTY WINDS THIS AFTERNOON THROUGH THE END OF THE TAF
VALID PERIOD.
AREAS OF MVFR FOG HAVE DEVELOPED OVER THE SOUTHERN SECTIONS OF
CENTRAL NC IN THE LAST FEW HOURS. LATEST GUIDANCE SUPPORTS A PERIOD
OF IFR/LIFR FOG AT FAY EARLY THIS MORNING. VFR CONDITIONS ELSEWHERE
THIS MORNING. A CLIPPER COLD FRONT WILL SWEEP ACROSS THE AREA THIS
AFTERNOON/EARLY EVENING... AT APPROXIMATELY 18Z-20Z AT INT/GSO...
20Z-22Z AT RDU... AND 22Z-00Z AT FAY. A SHORT PERIOD (LIKELY AROUND
2-3 HRS AT MOST) OF MVFR CIGS/VSBYS IN SNOW SHOWERS IS EXPECTED WITH
FRONTAL PASSAGE. SURFACE WINDS FROM THE SW WILL INCREASE IN THE FEW
HOURS BEFORE FRONTAL PASSAGE... THEN REMAIN STRONG AND GUSTY AS THEY
SHIFT TO NW BEHIND THE FRONT... LASTING THROUGH 06Z. VFR CIGS/VSBYS
ARE EXPECTED AFTER FRONTAL PASSAGE.
LOOKING BEYOND 06Z EARLY THU MORNING: BRISK AND OCCASIONALLY GUSTY
NW SURFACE WINDS WILL PERSIST THROUGH THU. VFR CONDITIONS ARE
EXPECTED TO DOMINATE THROUGH FRI NIGHT WITH FRIGID HIGH PRESSURE
BUILDING IN. ANOTHER STORM SYSTEM APPROACHING FROM THE WEST AND SW
WILL BRING LIKELY SUB-VFR CONDITIONS WITH PRECIPITATION STARTING IN
THE NW EARLY SAT MORNING BEFORE SPREADING AREAWIDE SAT. SUB-VFR
CONDITIONS AND STRONG/SHIFTING WINDS WILL LAST THROUGH SUN AS A WARM
FRONT TRACKS NORTHWARD THROUGH THE REGION. -GIH
&&
.CLIMATE...
THE FOLLOWING ARE RECORD LOW AND LOW MAXIMUM TEMPERATURES FOR
FEBRUARY 19TH...AND 20TH...FOR GSO...RDU...AND FAY...
RECORD LOWS
GSO RDU FAY
FEBRUARY 19: 12 IN 1979 11 IN 1979 8 IN 1958
FEBRUARY 20: 14 IN 1934 13 IN 1979 12 IN 1958
FEBRUARY 21: 13 IN 1959 8 IN 1896 16 IN 1958
RECORD LOW MAXIMUMS
GSO RDU FAY
FEBRUARY 19: 32 IN 1958 31 IN 1903 26 IN 1979
FEBRUARY 20: 29 IN 1947 32 IN 1947 37 IN 1972
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 10 AM EST WEDNESDAY FOR
NCZ007>011-021>028-038>043-073>078-083>086-088-089.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...HARTFIELD
SHORT TERM...BADGETT
LONG TERM...ELLIS
AVIATION...HARTFIELD
CLIMATE...RAH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
255 AM EST WED FEB 18 2015
.SYNOPSIS...AN ARCTIC COLD FRONT WILL CROSS THE AREA THIS AFTERNOON
THROUGH EARLY EVENING. FRIGID HIGH PRESSURE WILL BUILD OVER THE AREA
THIS EVENING THROUGH FRIDAY... BRINGING NEAR RECORD LOW TEMPERATURES
AND VERY LOW WIND CHILLS. ANOTHER STORM SYSTEM WILL APPROACH FROM
THE WEST EARLY SATURDAY.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
AS OF 1010 PM TUESDAY...
...WINTER WEATHER ADVISORY FOR BLACK ICE TONIGHT THROUGH 1000 AM
WEDNESDAY...
TONIGHT:
A WINTER WEATHER ADVISORY FOR BLACK ICE REMAINS IN EFFECT
THROUGH 10 AM WEDNESDAY MORNING AS MANY ROADS (ESPECIALLY UNTREATED
SECONDARY ROADS) HAVE OR WILL REFREEZE TONIGHT WITH WHATS LEFT OF
ICE/SNOW/SLEET MELT ON THEM OR REMAIN SLEET/SNOW/ICE COVERED.
THE MAIN MID AND HIGH CLOUD SHIELD IS GENERALLY PUSHING OFF TO THE
NORTH AND EAST OF THE AREA THIS EVENING. HOWEVER... WITH THE MAIN
DEEP TROUGH AXIS TO THE WEST OF THE REGION AND ANOTHER EMBEDDED S/W
LOCATED OVER OK/TX SHIFTING EAST/NORTHEASTWARD EXPECT WE WILL STILL
SEE SOME MID AND HIGH CLOUDS MOVE ACROSS THE REGION OVERNIGHT. BOTH
THE HRRR AND NAM HAVE PICKED UP ON THE FACT THAT DEWPOINTS HAVE
REMAINED HIGHER THAN EXPECTED ACROSS THE AREA THIS EVENING. BOTH THE
NAM AND HRRR SHOW SOME SORT OF WEAK BOUNDARY DROPPING SOUTHWARD OUT
OF VA LATE THIS EVENING INTO THE OVERNIGHT (SHOWN MAINLY IN
DEWPOINT FIELDS). HOWEVER... BOTH THE NAM AND HRRR SHOW THIS WEAK
BOUNDARY STALLING AS IT TRIES TO PUSH INTO SOUTHERN PORTIONS OF THE
AREA... WITH POCKETS OF DENSE FOG AND LOW CLOUDS DEVELOPING ACROSS
THE SOUTHERN PIEDMONT AND SANDHILLS. IN FACT SOME IFR TO AT TIMES
LIFR FOG HAS DEVELOPED ACROSS THE SOUTHERN PIEDMONT ALREADY.
THUS... WE PLAN ON RAISING LOW TEMPS ACROSS SOUTHERN PORTIONS OF THE
AREA THIS EVENING AND PARTS OF THE COASTAL PLAIN. GIVEN WE ALREADY
HAVE A WINTER WEATHER ADVISORY FOR BLACK ICE OUT FOR THE ENTIRE
AREA... DO NOT PLAN ON ISSUING ANY ADDITIONAL HEADLINES FOR
THE POSSIBILITY OF SOME POCKETS OF FREEZING FOG. EXPECT LOW TEMPS TO
RANGE FROM THE UPPER TEENS NORTH TO THE MID TO UPPER 20S SOUTH.
WEDNESDAY:
IT APPEARS THAT A VERY BRIEF WINDOW OF TIME FOR SOME MODERATION IN
TEMPERATURES WILL OCCUR WEDNESDAY BEFORE THE BOTTOM LITERALLY
FALLS OUT. HOWEVER... STRONG HEIGHT FALLS OUT AHEAD OF THE
APPROACHING LEAD VORTICITY MAXIMUM WILL QUICKLY LEAD TO INCREASING
CLOUDINESS AND WILL SHUT DOWN THE WARMING IN THE PIEDMONT. JUST AS
WITH THE ARCTIC FRONT THAT PASSED THROUGH THE REGION LAST
WEEKEND... THERE IS A CHANCE OF SHOWERS WITH THIS FRONT. THE BEST
CHANCE OF SHOWERS APPEARS TO THE FOR THE NORTHERN AREAS OF THE
PIEDMONT... FROM THE TRIAD TO THE TRIANGLE AREAS... BETWEEN NOON
AND 500 PM. A SHORT PERIOD OF LIFT ALONG WITH STEEPENING LAPSE
RATES BETWEEN THE SURFACE AND H7 AND MOISTENING FROM THE SURFACE
THROUGH THE -15/-20C LEVEL JUSTIFIES GOOD CHANCES OF SHOWERS IN
THESE AREAS. SATURATION AND LIFT WILL BE LESS TO THE SOUTH AND
EAST WHERE ONLY SLIGHT CHANCES WILL BE FORECAST. THE TEMPERATURE
PROFILES SUGGEST SNOW SHOWERS AS THE MAIN PRECIPITATION TYPE.
HOWEVER... THE BOUNDARY LAYER SHOULD REVEAL TEMPERATURES
APPROACHING 40 BRIEFLY BEFORE THE FRONTAL PASSAGE. THEREFORE...
SNOW ACCUMULATIONS ARE NOT ANTICIPATED OTHER THAN POSSIBLY A LIGHT
DUSTING (UNDER A HALF INCH) IN HEAVIER BUT BRIEF SHOWERS... AND
CONFINED TO THE NORTHERN PIEDMONT AS MENTIONED BEFORE. HIGHS MID
30S NW TO MID 40S SE... FALLING LATE AFTERNOON IN THE NW.
&&
.SHORT TERM /WEDNESDAY NIGHT/...
AS OF 337 PM TUESDAY...
...PREPARE FOR DANGEROUS LIFE THREATENING COLD...
NW WINDS 15-25 MPH WILL GUST TO 35-40 MPH WEDNESDAY NIGHT WITH
RAPIDLY CLEARING EXPECTED. VERY INTENSE COLD AIR ADVECTION WILL
LEAD TO LOWS OF 5-15 NW TO SE BY THURSDAY MORNING.
WIND CHILL ADVISORIES WILL LIKELY BE NEEDED WEDNESDAY NIGHT AND
THURSDAY WHEN WIND CHILL INDICES SHOULD RANGE BETWEEN ZERO AND 15
BELOW ZERO.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 300 AM WEDNESDAY...
THE LONG TERM BEGINS WITH A POSITIVELY TILTED UPPER LEVEL TROUGH
EXTENDING DOWN THE EAST COAST WITH A STRONG SURFACE HIGH CENTERED
OVER THE OHIO VALLEY. THIS WILL KEEP CENTRAL NC ROOTED IN THE COLD
AIR ADVECTION REGIME WITH NORTHERLY SFC FLOW AND NWLY FLOW ALOFT.
VERY COLD AND DRY AIRMASS WITH HIGHS ONLY IN THE LOW TO MID 20S. THE
SFC HIGH DRIFTS EAST AND SETS UP OVER EASTERN NC FRIDAY NIGHT WHICH
WILL TURN WINDS AROUND TO SOUTHERLY RETURN FLOW. THIS WILL NOT BE IN
TIME TO HELP TEMPS ALL THAT MUCH AS LOWS WILL BE IN THE MID TEENS.
STILL THIS IS WARMER THAN PREVIOUS NIGHTS. BACK TO WEST...AN
INVERTED TROUGH EXTENDING INTO THE TENNESSEE VALLEY FROM A PARENT
LOW OVER NORTH TEXAS WILL BE PRODUCING AN AREA OF STRONG LOW LEVEL
CONVERGENCE AND PRECIPITATION THAT IS THE PRECURSOR TO OUR NEXT
SYSTEM. INCREASING CLOUDS CAN BE EXPECTED AHEAD OF THIS SYSTEM LATE
FRIDAY NIGHT INTO SATURDAY MORNING.
OVERALL...MODELS HAVE COME INTO BETTER AGREEMENT WITH REGARD TO THE
EVOLUTION OF THE SYSTEM APPROACHING FROM THE WEST ON SATURDAY. THERE
STILL ARE FINER DIFFERENCES THAT MAY MATTER CONSIDERABLY IN HOW THE
FINAL SCENARIO PLAYS OUT. FIRST...THE EUROPEAN HAS PICKED UP THE LOW
PRESSURE WEST OF THE MOUNTAINS THAT THE GFS WAS SHOWING YESTERDAY. A
MUCH STRONGER WAVE IN THE UPPER LEVEL PATTERN OVER TEXAS IN THE GFS
IS PRODUCING A MUCH STRONGER LOW AND IS SLOWER WITH ITS PROGRESSION
UP THE BACK OF THE COLD FRONT. THIS WILL NOT MATTER IN REGARDS TO
POTENTIAL WINTER P-TYPE ON SATURDAY AS MUCH AS IT WILL FOR THE
TIMING OF THE ADVANCEMENT OF THE COLD FRONT THROUGH THE STATE ON
SUNDAY WHICH IS FASTER IN THE ECMWF. ANOTHER COMPROMISE THE MODELS
HAVE MADE IS WITH THE IN-SITU DAMMING SCENARIO AS THE SFC HIGH MOVES
OUT TO SEA. BOTH MODELS ARE NOW PRODUCING A WEDGE FRONT BUT IT IS
MUCH WEAKER IN THE GFS THEN PRIOR RUNS AND THE HIGH PUSHES FURTHER
OUT TO SEA FASTER THAN PREVIOUS RUNS AND THUS BOTH MODELS LOSE THE
WEDGE QUICKLY LATE SATURDAY AFTERNOON/EVENING. BECAUSE OF THIS...THE
OOZ RUN OF THE GFS HAS TRENDED A BIT WARMER AS ISENTROPIC LIFT WILL
BE LESS PRONOUNCED EARLIER IN THE DAY.
THE UPSHOT IN THE FORECAST SOUNDINGS IS A REAL GRAB BAG OF POTENTIAL
PRECIPITATION TYPES FOR THE TRIAD WITH APPRECIABLE DIFFERENCES
BETWEEN THE THERMAL PROFILES EVEN BETWEEN KGSO AND KINT. THE GENERAL
TREND WILL BE A GREATER LIKELIHOOD OF SNOW NORTH AND WEST AND LESS
SO APPROACHING GREENSBORO AND POINTS SOUTH AND EAST WHERE SLEET AND
EVEN FREEZING RAIN COULD BE MORE LIKELY. VERY EARLY FOR THESE
DETAILS TO BE IRONED OUT SO WE WILL CALL IT WINTERY MIX FOR NOW.
PRECIPITATION DOES LOOK CONFINED TO THE TRIAD HOWEVER AND POINTS
EAST OF HIGHWAY 1 SHOULD REMAIN DRY FOR MUCH OF THE DAY ON SATURDAY.
HIGHS GENERALLY IN THE LOWER 40S. EXPECT A NON-DIURNAL TEMPERATURE
CURVE FOR SATURDAY NIGHT WITH TEMPERATURES BEGINNING TO WARM
CONSIDERABLY AFTER 00Z SUNDAY AS WARM AIR ADVECTION AHEAD OF THE
COLD FRONT BEGINS. LOWS IN THE MID TO UPPER 30S OCCURRING EARLY IN
THE EVENING.
RAIN ASSOCIATED WITH THE COLD FRONT WILL MOVE IN FOR SUNDAY.
CONFIDENCE IN THIS BEING ALL LIQUID IS HIGH CONSIDERING THE
OVERNIGHT RISE IN TEMPERATURES WHICH WILL CONTINUE ON SUNDAY AND THE
LOSS OF SATURATION ALOFT IN THE ICE NUCLEATION ZONE. IN
FACT...TEMPERATURES WARM SO MUCH IN THE LOW LEVELS THAT INSTABILITY
CREEPS IN BY LATE SUNDAY AFTERNOON/EARLY EVENING AND LOW AND MID
LEVEL LAPSE RATES INCREASE. RISES ARE MINIMAL BUT WOULD NOT RULE OUT
THE CHANCE FOR A HEAVY CONVECTIVE SHOWER OR ISOLATED THUNDERSTORM.
HIGHS IN THE MID TO UPPER 50S. PRECIPITATION IS EXPECTED TO END
AFTER 6Z MONDAY. TOTAL QPF AMOUNTS ARE VERY UNCERTAIN AT THIS TIME
BUT EXPECT MORE IN THE TRIAD THAN POINTS EAST. LOWS IN THE MID TO
UPPER 30S.
COLDER AND DRIER BEHIND THE FRONT WITH NORTHEASTERLY SFC FLOW ON
MONDAY WITH HIGHS IN THE MID 40S AND LOWS MONDAY NIGHT IN THE UPPER
20S. DRY FOR TUESDAY AS WELL AS LOW PRESSURE MOVES INTO THE GREAT
LAKES REGION. HIGHS IN THE MID TO UPPER 40S.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
AS OF 1235 AM WEDNESDAY...
PRIMARY AVIATION CONCERNS NEXT 24 HRS: SUB-VFR CIGS/VSBYS AT FAY
EARLY THIS MORNING (BEFORE DAYBREAK)... A PERIOD OF MVFR CIGS AND
SCATTERED SNOW SHOWERS TODAY FROM MID AFTERNOON TO EARLY EVENING...
AND STRONG/GUSTY WINDS THIS AFTERNOON THROUGH THE END OF THE TAF
VALID PERIOD.
AREAS OF MVFR FOG HAVE DEVELOPED OVER THE SOUTHERN SECTIONS OF
CENTRAL NC IN THE LAST FEW HOURS. LATEST GUIDANCE SUPPORTS A PERIOD
OF IFR/LIFR FOG AT FAY EARLY THIS MORNING. VFR CONDITIONS ELSEWHERE
THIS MORNING. A CLIPPER COLD FRONT WILL SWEEP ACROSS THE AREA THIS
AFTERNOON/EARLY EVENING... AT APPROXIMATELY 18Z-20Z AT INT/GSO...
20Z-22Z AT RDU... AND 22Z-00Z AT FAY. A SHORT PERIOD (LIKELY AROUND
2-3 HRS AT MOST) OF MVFR CIGS/VSBYS IN SNOW SHOWERS IS EXPECTED WITH
FRONTAL PASSAGE. SURFACE WINDS FROM THE SW WILL INCREASE IN THE FEW
HOURS BEFORE FRONTAL PASSAGE... THEN REMAIN STRONG AND GUSTY AS THEY
SHIFT TO NW BEHIND THE FRONT... LASTING THROUGH 06Z. VFR CIGS/VSBYS
ARE EXPECTED AFTER FRONTAL PASSAGE.
LOOKING BEYOND 06Z EARLY THU MORNING: BRISK AND OCCASIONALLY GUSTY
NW SURFACE WINDS WILL PERSIST THROUGH THU. VFR CONDITIONS ARE
EXPECTED TO DOMINATE THROUGH FRI NIGHT WITH FRIGID HIGH PRESSURE
BUILDING IN. ANOTHER STORM SYSTEM APPROACHING FROM THE WEST AND SW
WILL BRING LIKELY SUB-VFR CONDITIONS WITH PRECIPITATION STARTING IN
THE NW EARLY SAT MORNING BEFORE SPREADING AREAWIDE SAT. SUB-VFR
CONDITIONS AND STRONG/SHIFTING WINDS WILL LAST THROUGH SUN AS A WARM
FRONT TRACKS NORTHWARD THROUGH THE REGION. -GIH
&&
.CLIMATE...
THE FOLLOWING ARE RECORD LOW AND LOW MAXIMUM TEMPERATURES FOR
FEBRUARY 19TH...AND 20TH...FOR GSO...RDU...AND FAY...
RECORD LOWS
GSO RDU FAY
FEBRUARY 19: 12 IN 1979 11 IN 1979 8 IN 1958
FEBRUARY 20: 14 IN 1934 13 IN 1979 12 IN 1958
FEBRUARY 21: 13 IN 1959 8 IN 1896 16 IN 1958
RECORD LOW MAXIMUMS
GSO RDU FAY
FEBRUARY 19: 32 IN 1958 31 IN 1903 26 IN 1979
FEBRUARY 20: 29 IN 1947 32 IN 1947 37 IN 1972
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 10 AM EST WEDNESDAY FOR
NCZ007>011-021>028-038>043-073>078-083>086-088-089.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...RAH
SHORT TERM...BADGETT
LONG TERM...ELLIS
AVIATION...HARTFIELD
CLIMATE...RAH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1235 AM EST WED FEB 18 2015
.SYNOPSIS...AN ARCTIC COLD FRONT WILL CROSS THE AREA THIS AFTERNOON
THROUGH EARLY EVENING. FRIGID HIGH PRESSURE WILL BUILD OVER THE AREA
THIS EVENING THROUGH FRIDAY... BRINGING NEAR RECORD LOW TEMPERATURES
AND VERY LOW WIND CHILLS. ANOTHER STORM SYSTEM WILL APPROACH FROM
THE WEST EARLY SATURDAY.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
AS OF 1010 PM TUESDAY...
...WINTER WEATHER ADVISORY FOR BLACK ICE TONIGHT THROUGH 1000 AM
WEDNESDAY...
TONIGHT:
A WINTER WEATHER ADVISORY FOR BLACK ICE REMAINS IN EFFECT
THROUGH 10 AM WEDNESDAY MORNING AS MANY ROADS (ESPECIALLY UNTREATED
SECONDARY ROADS) HAVE OR WILL REFREEZE TONIGHT WITH WHATS LEFT OF
ICE/SNOW/SLEET MELT ON THEM OR REMAIN SLEET/SNOW/ICE COVERED.
THE MAIN MID AND HIGH CLOUD SHIELD IS GENERALLY PUSHING OFF TO THE
NORTH AND EAST OF THE AREA THIS EVENING. HOWEVER... WITH THE MAIN
DEEP TROUGH AXIS TO THE WEST OF THE REGION AND ANOTHER EMBEDDED S/W
LOCATED OVER OK/TX SHIFTING EAST/NORTHEASTWARD EXPECT WE WILL STILL
SEE SOME MID AND HIGH CLOUDS MOVE ACROSS THE REGION OVERNIGHT. BOTH
THE HRRR AND NAM HAVE PICKED UP ON THE FACT THAT DEWPOINTS HAVE
REMAINED HIGHER THAN EXPECTED ACROSS THE AREA THIS EVENING. BOTH THE
NAM AND HRRR SHOW SOME SORT OF WEAK BOUNDARY DROPPING SOUTHWARD OUT
OF VA LATE THIS EVENING INTO THE OVERNIGHT (SHOWN MAINLY IN
DEWPOINT FIELDS). HOWEVER... BOTH THE NAM AND HRRR SHOW THIS WEAK
BOUNDARY STALLING AS IT TRIES TO PUSH INTO SOUTHERN PORTIONS OF THE
AREA... WITH POCKETS OF DENSE FOG AND LOW CLOUDS DEVELOPING ACROSS
THE SOUTHERN PIEDMONT AND SANDHILLS. IN FACT SOME IFR TO AT TIMES
LIFR FOG HAS DEVELOPED ACROSS THE SOUTHERN PIEDMONT ALREADY.
THUS... WE PLAN ON RAISING LOW TEMPS ACROSS SOUTHERN PORTIONS OF THE
AREA THIS EVENING AND PARTS OF THE COASTAL PLAIN. GIVEN WE ALREADY
HAVE A WINTER WEATHER ADVISORY FOR BLACK ICE OUT FOR THE ENTIRE
AREA... DO NOT PLAN ON ISSUING ANY ADDITIONAL HEADLINES FOR
THE POSSIBILITY OF SOME POCKETS OF FREEZING FOG. EXPECT LOW TEMPS TO
RANGE FROM THE UPPER TEENS NORTH TO THE MID TO UPPER 20S SOUTH.
WEDNESDAY:
IT APPEARS THAT A VERY BRIEF WINDOW OF TIME FOR SOME MODERATION IN
TEMPERATURES WILL OCCUR WEDNESDAY BEFORE THE BOTTOM LITERALLY
FALLS OUT. HOWEVER... STRONG HEIGHT FALLS OUT AHEAD OF THE
APPROACHING LEAD VORTICITY MAXIMUM WILL QUICKLY LEAD TO INCREASING
CLOUDINESS AND WILL SHUT DOWN THE WARMING IN THE PIEDMONT. JUST AS
WITH THE ARCTIC FRONT THAT PASSED THROUGH THE REGION LAST
WEEKEND... THERE IS A CHANCE OF SHOWERS WITH THIS FRONT. THE BEST
CHANCE OF SHOWERS APPEARS TO THE FOR THE NORTHERN AREAS OF THE
PIEDMONT... FROM THE TRIAD TO THE TRIANGLE AREAS... BETWEEN NOON
AND 500 PM. A SHORT PERIOD OF LIFT ALONG WITH STEEPENING LAPSE
RATES BETWEEN THE SURFACE AND H7 AND MOISTENING FROM THE SURFACE
THROUGH THE -15/-20C LEVEL JUSTIFIES GOOD CHANCES OF SHOWERS IN
THESE AREAS. SATURATION AND LIFT WILL BE LESS TO THE SOUTH AND
EAST WHERE ONLY SLIGHT CHANCES WILL BE FORECAST. THE TEMPERATURE
PROFILES SUGGEST SNOW SHOWERS AS THE MAIN PRECIPITATION TYPE.
HOWEVER... THE BOUNDARY LAYER SHOULD REVEAL TEMPERATURES
APPROACHING 40 BRIEFLY BEFORE THE FRONTAL PASSAGE. THEREFORE...
SNOW ACCUMULATIONS ARE NOT ANTICIPATED OTHER THAN POSSIBLY A LIGHT
DUSTING (UNDER A HALF INCH) IN HEAVIER BUT BRIEF SHOWERS... AND
CONFINED TO THE NORTHERN PIEDMONT AS MENTIONED BEFORE. HIGHS MID
30S NW TO MID 40S SE... FALLING LATE AFTERNOON IN THE NW.
&&
.SHORT TERM /WEDNESDAY NIGHT/...
AS OF 337 PM TUESDAY...
...PREPARE FOR DANGEROUS LIFE THREATENING COLD...
NW WINDS 15-25 MPH WILL GUST TO 35-40 MPH WEDNESDAY NIGHT WITH
RAPIDLY CLEARING EXPECTED. VERY INTENSE COLD AIR ADVECTION WILL
LEAD TO LOWS OF 5-15 NW TO SE BY THURSDAY MORNING.
WIND CHILL ADVISORIES WILL LIKELY BE NEEDED WEDNESDAY NIGHT AND
THURSDAY WHEN WIND CHILL INDICES SHOULD RANGE BETWEEN ZERO AND 15
BELOW ZERO.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
AS OF 300 PM TUESDAY...
...POTENTIALLY HISTORIC ARCTIC AIR MASS WILL CONTINUE TO BE IN
PLACE WITH RECORD LOW/LOW MAXIMUM TEMPERATURES EXPECTED
THURSDAY...THURSDAY NIGHT...FRIDAY AND POSSIBLY FRIDAY NIGHT...
THIS COLD WAVE SHOULD RIVAL THE COLD WAVES THAT HAVE OCCURRED IN
FEBRUARY... POTENTLY SETTING MONTHLY COLD RECORDS AS WELL.
THURSDAY THROUGH FRIDAY NIGHT: THIS PART OF THE FORECAST IS EXPECTED
TO BE DRY WITH RECORD SETTING TEMPERATURES. THE UPPER LEVEL HIGH
WILL REMAIN OVER SOUTHERN ONTARIO AND NEW ENGLAND...WITH THE TROUGH
EXTENDING SOUTH THROUGH THE MID-ATLANTIC...SLOWLY PROGRESSING
EASTWARD OFF THE COAST. MEANWHILE AT THE SURFACE...THE COASTAL LOW
WILL CONTINUE ITS NORTHEAST TREK AS THE ARCTIC HIGH BUILDS INTO THE
REGION. SUBSIDENCE UNDER THE NW FLOW AS THE HIGH BUILDS IN WILL KEEP
CENTRAL NC DRY...BUT BITTER COLD. THE TIGHT PRESSURE GRADIENT
BETWEEN THE EXITING LOW AND APPROACHING HIGH WILL RESULT IN FAIRLY
DESCENT WINDS IN THE 10-20 MPH RANGE ON THURSDAY. THE WINDS WILL
ABATE THURSDAY NIGHT AS THE HIGH MOVES OVER THE AREA...WITH
GENERALLY LIGHT AND VARIABLE WINDS THROUGH FRIDAY NIGHT.
TEMPERATURES: WITH HIGHS ON THURSDAY ALREADY AS LOW AS THE MID TEENS
IN THE NORTH TO MID 20S SOUTH...THE WIND MAY STILL PRODUCE WIND
CHILLS BELOW ZERO FOR MUCH OF THE DAY THURSDAY. THURSDAY NIGHT
LOWS SHOULD DIP TO BETWEEN 0 AND 5 NW TO NEAR 10 SE. SOME SUB-ZERO
READINGS WILL BE POSSIBLE IN THE PIEDMONT WHERE THE ICE/SNOW PACK
REMAINS. FAIRLY HIGH CONFIDENCE THAT HIGHS ON FRIDAY WILL REMAIN
BELOW FREEZING...MID 20S NORTH TO UPPER 20S SOUTH. LOWS SHOULD
REBOUND SLIGHTLY ON FRIDAY NIGHT...MAINLY IN THE 10-15 DEGREE
RANGE BUT STILL CLOSE TO RECORD VALUES (SEE CLIMATE SECTION
BELOW).
SATURDAY AND SUNDAY: THERE IS SLIGHTLY BETTER AGREEMENT BETWEEN THE
MODELS FOR THE WEEKEND...HOWEVER CONFIDENCE IS STILL LOW ON HOW MUCH
AND WHAT TYPE OF PRECIPITATION WE WILL SEE AND WHEN IT WILL OCCUR.
THERE IS A CHANCE THAT A COLD AIR WEDGE WILL SET UP OVER THE NC
PIEDMONT ON SATURDAY...AND WITH AN APPROACHING LOW PRESSURE SYSTEM
FROM THE WEST...EXPECT BEST CHANCES FOR PRECIP TO BE ACROSS THE NW
ON SATURDAY...WITH THE SANDHILLS LIKELY REMAINING DRY. FREEZING
RAIN AND/OR SLEET MAY OCCUR IF THE PRECIPIATION CAN SNEAK INTO
THE NW PIEDMONT BEFORE THE ARCTIC AIR RETREATS. THIS IS BECOMING
AN INCREASING POSSIBILITY. WE WILL HAVE TO KEEP WATCHING THIS ONE
FOR ICING POTENTIAL.
AS OF THE LATEST MODEL RUNS...SUNDAY AND SUNDAY NIGHT LOOK TO BE
THE WETTEST AS THE COLD FRONT APPROACHES AND MOVES THROUGH NC.
RAIN IS PREFERRED... BUT MODELS MAY BE BLOWING AWAY THE EXTENSIVE
COLD AIR TOO SOON. TEMPS WILL BE DIFFICULT TO FORECAST GIVEN THE
UNCERTAINTY OF THE WEDGES EXISTENCE AND HOW LONG/WHERE IT WILL
LINGER. BOTH MODELS AGREE THAT THE COLD FRONT WILL BE MOST OF THE
WAY THROUGH CENTRAL NC BY 12Z MONDAY. FOR NOW...EXPECT HIGHS IN
THE 30S NORTHWEST TO MID 40S SOUTHEAST ON SATURDAY...INCREASING
INTO THE 40S AND 50S ON SUNDAY.
MONDAY AND TUESDAY: THE PRECIPITATION SHOULD MOVE OUT OF THE AREA
WITH THE FRONT ON MONDAY...WITH HIGH PRESSURE BUILDING INTO THE
REGION BEHIND IT. COOLER TEMPERATURES WILL RETURN EARLY NEXT WEEK
WITH HIGHS MAINLY IN THE LOW TO MID 40S AND LOWS IN THE MID 30S TO
AROUND 30 DEGREES.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
AS OF 1235 AM WEDNESDAY...
PRIMARY AVIATION CONCERNS NEXT 24 HRS: SUB-VFR CIGS/VSBYS AT FAY
EARLY THIS MORNING (BEFORE DAYBREAK)... A PERIOD OF MVFR CIGS AND
SCATTERED SNOW SHOWERS TODAY FROM MID AFTERNOON TO EARLY EVENING...
AND STRONG/GUSTY WINDS THIS AFTERNOON THROUGH THE END OF THE TAF
VALID PERIOD.
AREAS OF MVFR FOG HAVE DEVELOPED OVER THE SOUTHERN SECTIONS OF
CENTRAL NC IN THE LAST FEW HOURS. LATEST GUIDANCE SUPPORTS A PERIOD
OF IFR/LIFR FOG AT FAY EARLY THIS MORNING. VFR CONDITIONS ELSEWHERE
THIS MORNING. A CLIPPER COLD FRONT WILL SWEEP ACROSS THE AREA THIS
AFTERNOON/EARLY EVENING... AT APPROXIMATELY 18Z-20Z AT INT/GSO...
20Z-22Z AT RDU... AND 22Z-00Z AT FAY. A SHORT PERIOD (LIKELY AROUND
2-3 HRS AT MOST) OF MVFR CIGS/VSBYS IN SNOW SHOWERS IS EXPECTED WITH
FRONTAL PASSAGE. SURFACE WINDS FROM THE SW WILL INCREASE IN THE FEW
HOURS BEFORE FRONTAL PASSAGE... THEN REMAIN STRONG AND GUSTY AS THEY
SHIFT TO NW BEHIND THE FRONT... LASTING THROUGH 06Z. VFR CIGS/VSBYS
ARE EXPECTED AFTER FRONTAL PASSAGE.
LOOKING BEYOND 06Z EARLY THU MORNING: BRISK AND OCCASIONALLY GUSTY
NW SURFACE WINDS WILL PERSIST THROUGH THU. VFR CONDITIONS ARE
EXPECTED TO DOMINATE THROUGH FRI NIGHT WITH FRIGID HIGH PRESSURE
BUILDING IN. ANOTHER STORM SYSTEM APPROACHING FROM THE WEST AND SW
WILL BRING LIKELY SUB-VFR CONDITIONS WITH PRECIPITATION STARTING IN
THE NW EARLY SAT MORNING BEFORE SPREADING AREAWIDE SAT. SUB-VFR
CONDITIONS AND STRONG/SHIFTING WINDS WILL LAST THROUGH SUN AS A WARM
FRONT TRACKS NORTHWARD THROUGH THE REGION. -GIH
&&
.CLIMATE...
THE FOLLOWING ARE RECORD LOW AND LOW MAXIMUM TEMPERATURES FOR
FEBRUARY 19TH...AND 20TH...FOR GSO...RDU...AND FAY...
RECORD LOWS
GSO RDU FAY
FEBRUARY 19: 12 IN 1979 11 IN 1979 8 IN 1958
FEBRUARY 20: 14 IN 1934 13 IN 1979 12 IN 1958
FEBRUARY 21: 13 IN 1959 8 IN 1896 16 IN 1958
RECORD LOW MAXIMUMS
GSO RDU FAY
FEBRUARY 19: 32 IN 1958 31 IN 1903 26 IN 1979
FEBRUARY 20: 29 IN 1947 32 IN 1947 37 IN 1972
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 10 AM EST WEDNESDAY FOR
NCZ007>011-021>028-038>043-073>078-083>086-088-089.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...RAH
SHORT TERM...BADGETT
LONG TERM...KC
AVIATION...HARTFIELD
CLIMATE...RAH
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
944 PM CST THU FEB 19 2015
.UPDATE...
ISSUED AT 937 PM CST THU FEB 19 2015
SYSTEM MOVING THROUGH IS VERY UNIMPRESSIVE ON RADAR AND
OBSERVATIONS/WEBCAMS. A DUSTING IN DEVILS LAKE (MAYBE A FEW
TENTHS) BUT SNOW APPEARS VERY FINE. RAP MODEL DOESNT HAVE ANY
CONCENTRATED FRONTOGENSIS AND MAIN WARM ADV AT 850 IS WELL SOUTH
OF THE STATE. NET RESULT IS ENOUGH MOISTURE AND WEAK LIFT FOR
LIGHT PRECIP BUT NOTHING TO ENCOURAGE BIGGER SNOW FLAKE GROWTH. SO
TRIMMED SNOW TOTALS TO UNDER 1 INCH.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 300 PM CST THU FEB 19 2015
THE MAIN CHALLENGE WILL BE LIGHT SNOW TONIGHT INTO FRI...THEN
BITTERLY COLD WIND CHILLS DEVELOPING SATURDAY INTO SUNDAY. MODELS
ARE IN GOOD AGREEMENT...SO CONFIDENCE IS FAIRLY HIGH WITH THIS
FORECAST.
FOR TONIGHT...A BAND OF LIGHT SNOW WILL SLOWLY MOVE FROM WEST TO
EAST WITHIN MID LEVEL WAA/ISENTROPIC LIFT. THERE IS A FAIRLY
CONCENTRATED AREA OF LIFT...BUT IT ONLY LASTS FROM 3-6HR. THIS
COUPLED WITH THE FACT THAT WE ARE IN FAST NW FLOW ALOFT...AND MID
LEVEL LAPSE RATES ARE FAIRLY STABLE...NOT EXPECTING MUCH IN THE
WAY OF PERSISTENT MESOSCALE BANDING. THE BEST CHANCE FOR AN INCH
OR SO SHOULD BE IN THE NORTH INTO NW MN. THERE WILL ALSO BE
SOUTHERLY WINDS THAT COULD SUSTAIN NEAR 20KT IN THE NORTHERN
VALLEY FROM 00-06Z...SO IF THIS OCCURS WITH LIGHT SNOW THEN PATCHY
BLOWING SNOW IS SUGGESTED WITH THE CANADIAN BLOWING SNOW MODEL.
THEREFORE...WILL ADD SOME PATCHY BLOWING SNOW IN THE NORTH VALLEY
FROM 00-06Z. TEMPS WILL SLOWLY RISE OVERNIGHT...ALTHOUGH WITH
SOUTHERLY WINDS IT WILL NOT FEEL WARM AT ALL...EVEN THOUGH WE
SHOULD REMAIN OUT OF WIND CHILL CRITERIA.
ON FRIDAY...A SFC LOW MOVES THROUGH IN THE MORNING WITH COLD
ADVECTION DEVELOPING BY AFTERNOON FROM NORTH TO SOUTH. THERE WILL
BE DEEP LAYERED SATURATION...AND SOME LIFTING NEAR SEVERAL
SHORTWAVES SO THE CONTINUATION OF LIGHT SNOW/SNOW SHOWERS IS
POSSIBLE. NOT EXPECTING MUCH ADDITIONAL ACCUMULATION THOUGH.
FOR FRI NIGHT...TEMPS WILL FALL BEHIND A STRONG COLD FRONT AND
THERE COULD BE SOME DRIFTING/PATCHY BLOWING SNOW IN OPEN AREAS.
WILL NOT MENTION FOR NOW SINCE THIS WILL DEPEND ON HOW STRONG
WINDS GET...BUT SOMETHING TO MONITOR. WIND CHILLS MAY FALL INTO
THE 25 TO 30 BELOW RANGE LATE AT NIGHT AND THAT WILL BE THE MAIN
HAZARD.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 300 PM CST THU FEB 19 2015
FOR SAT THROUGH SUNDAY...A BITTERLY COLD AIRMASS WILL BE OVER THE
REGION WITH 925MB TEMPS DOWN TO AROUND -30C BY SAT AFTERNOON. THIS
COUPLED WITH STRONG NORTHERLY WINDS AROUND 15-20KT INTO SAT NIGHT
WILL PRODUCE BITTERLY COLD WIND CHILLS TO AT LEAST 40
BELOW...PERHAPS TO 45 BELOW LATE SAT NIGHT. NEEDLESS TO
SAY...WIND CHILL HEADLINES WILL BE NEEDED AS WE HEAD TOWARD THE
WEEKEND. THERE COULD EVEN BE SOME FLURRIES/SNOW SHOWERS ON SAT
ALONG WITH PATCHY BLOWING SNOW IN PRONE AREAS SAT NEAR ANY SNOW
SHOWERS...SO SOMETHING WE WILL MONITOR. ACTUAL AIR TEMPS WILL
LIKELY REMAIN BELOW ZERO SAT AND SUNDAY...WITH LOWS SAT NIGHT 20
TO 25 BELOW ALONG WITH DANGEROUS WIND CHILLS. IT SHOULD BE DRY
SUNDAY ALTHOUGH VERY COLD WITH ARCTIC HIGH PRESSURE MOVING
OVERHEAD.
FOR SUN NIGHT THROUGH THU...ARCTIC HIGH WILL MOVE OUT OF THE
REGION SUN NIGHT AND WESTERLY FLOW WILL PROVIDE A BRIEF WARM UP ON
MONDAY...WITH DAYTIME HIGHS IN THE 20S WEST AND MID TEENS EAST.
FOLLOWING THAT...A NORTHERLY UPPER FLOW PATTERN DOMINATES THE
WEEK...WITH AN UPPER HIGH OVER HUDSON BAY KICKING OFF A SHORT WAVE
THAT WILL ROTATE THROUGH OUR REGION MON NIGHT INTO TUE. THE
INCREASED CLOUD COVER WILL KEEP MODERATE OVERNIGHT TEMPS MON NIGHT
AND DAYTIME HIGHS TUESDAY IN THE MID TEENS. ANOTHER ARCTIC AIRMASS
DROPS IN FROM THE YUKON TERRITORY ON TUE NIGHT...BRINGING SUB ZERO
LOWS AND SINGLE DIGIT HIGHS BACK TO THE REGION FOR THE LATTER PART
OF THE WORK WEEK.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 706 PM CST THU FEB 19 2015
LEADING EDGE OF ALTOCU CLOUDS APPROACHING ROX-BJI-PKD AREA.
WILL SEE PROGRESSION EASTWARD OF 1-2SM IN LIGHT SNOW TONIGHT FROM
WEST TO EAST WITH CIGS DROPPING INTO THE MVFR RANGE. SOUTH WINDS
WILL BE GUSTY AT TIMES IN THE RRV. WINDS WILL TURN NORTHWEST 10-15
KTS FRIDAY AND LOOKS LIKE MVFR CIGS WILL REMAIN AS LIGHT SNOW END.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...RIDDLE
SHORT TERM...DK
LONG TERM...DK/SPEICHER
AVIATION...RIDDLE
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
1215 AM EST WED FEB 18 2015
.SYNOPSIS...
ANOTHER ARCTIC FRONT WILL CROSS THE AREA FROM WEST TO EAST THIS
EVENING INTO WEDNESDAY. ARCTIC HIGH PRESSURE WILL BE OVERHEAD BY
FRIDAY MORNING. THE NEXT COLD FRONT WILL DROP ACROSS THE GREAT
LAKES ON SATURDAY. A WAVE OF LOW PRESSURE MAY DEVELOP ON THE
FRONT.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
ENHANCED AREA OF SNOWFALL CONTINUES TO MOVE TO THE EAST NORTHEAST
ONTO LAKE ERIE THIS EVENING. RUC MODEL INDICATES THIS TREND WILL
CONTINUE. HOWEVER WE WILL NEED TO MONITOR NE OHIO INTO NW PA FOR A
BAND OF SLIGHTLY HEAVIER SNOWFALL. FORTUNATELY THIS AREA OF OF
STEADY LIGHT SNOW SHOULD KEEP MOVING AND LIMIT AMOUNTS. STILL
LOOKS LIKE AROUND AN INCH WILL BE THE HIGH SIDE FOR ACCUMULATIONS.
THESE HEAVIER AMOUNTS WILL LIKELY BE CLOSER TO THE
LAKESHORE...ESPECIALLY NEAR TOLEDO AND ACROSS EXTREME NE OHIO INTO
NW PA.
TEMPERATURES CONTINUE TO WARM SLIGHTLY AHEAD OF THE ARCTIC
BOUNDARY THIS EVENING. THE BOUNDARY WAS LOCATED FROM NEAR THE
THUMB OF MICHIGAN SOUTHWEST TO NEAR THE INDIANA/OHIO BORDER AS OF
03Z. THIS BOUNDARY WILL CONTINUE EASTWARD THROUGH THE OVERNIGHT
WITH TEMPERATURES DROPPING BACK INTO THE SINGLE DIGITS. THIS WILL
ALLOW WIND CHILL TEMPERATURES TO DIP TO AROUND 10 DEGREES BELOW
ZERO AROUND SUNRISE. SO IT WILL BE A CLOSE CALL FOR THE NEED OF A
WIND CHILL ADVISORY.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH FRIDAY NIGHT/...
THE FLOW WILL BE SOUTHWEST WEDNESDAY MORNING WITH PLENTY OF
MOISTURE AROUND...SO WILL KEEP CHANCE POPS. GOING WITH LIKELY FOR
THE SNOW BELT IN THE AFTERNOON AS THE FLOW BECOMES WNW WEDNESDAY
AFTERNOON. CONTINUING CHANCE POPS EVERYWHERE ELSE AS THE UPPER TROF
MOVES THROUGH.
FOR WEDNESDAY NIGHT THROUGH THURSDAY NIGHT THE SNOW BELT HAS THE
BEST CHANCE FOR SNOW WITH LOW POP CHANCES EVERYWHERE ELSE DECREASING
WITH TIME AS THE AIRMASS DRIES OUT AND THE HIGH STARTS BUILDING IN
FROM THE WEST. ON THE EDGE ABOUT THE AMOUNTS IN THE SNOW BELT. THE
NW FLOW IS USUALLY NOT THAT GOOD FOR SIGNIFICANT SNOWFALL AMOUNTS
EXCEPT OVER INLAND NW PA. HOWEVER...WITH THE AIRMASS SO DRY AND LAKE
ERIE FROZEN WE WILL NEED HELP FROM OTHER LAKES...EVEN FOR NW PA. WILL
CONTINUE TO MONITOR THIS THREAT.
DRY FRIDAY AND THEN A CHANCE OF SNOW FRIDAY NIGHT AS THE NEXT SYSTEM
APPROACHES. AT THIS TIME THE TIMING IS IN QUESTION BUT WILL NOT PUT
ANY RESOLUTION IN UNTIL THE TRENDS BECOME CLEARER.
THE MAIN THREAT WITH THIS NEXT SURGE OF COLD AIR WILL BE WIND
CHILLS. AT THIS TIME IT SEEMS LIKE A WIND CHILL ADVISORY WILL BE
GOOD ENOUGH. THE THREAT FOR NEEDING THIS HEADLINE WILL START
WEDNESDAY EVE AND LAST INTO FRIDAY MORNING. DID NOT ISSUE A
HEADLINE YET AS SOME QUESTIONS TO THE TIMING OF THE TEMPERATURE
DECREASE ETC. AT THIS TIME NOT THINKING WE WILL GET INTO WIND
CHILL WARNING CRITERIA OVER THE ENTIRE AREA...JUST SOME LOCATIONS.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
THE MODELS CONTINUE TO JUMP BACK AND FORTH WITH INCONSISTENCY ON
TIMING THE PASSAGE OF THE ARCTIC FRONT SAT NIGHT AND THE STRENGTH OF
A POSSIBLE LOW ALONG THE FRONT. NOW THE GFS IS SHOWING MORE OF A LOW
AND SLOWER FRONTAL PASSAGE TIMING. WILL CONTINUE TO AVERAGE THE
MODELS FOR THE FORECAST WITH MAINLY LAKE EFFECT BY LATE SUN/SUN
NIGHT.
HIGH PRESSURE EXPECTED TO BE OVER THE AREA FOR DRY CONDITIONS ON
MON. ECMWF AGAIN DIGS SHARPER TROUGH WITH NEXT SYSTEM FOR TUE WITH
STRONGER LOW. ONCE AGAIN...QUESTION THIS SO WILL SIDE A LITTLE MORE
WITH GFS WHICH STILL BRINGS MOISTURE AND ANOTHER THREAT FOR SNOW
INTO THE AREA WITH LESS WARMING.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
SCATTERED SNOW SHOWERS ACROSS NORTH CENTRAL OHIO CONTINUE TO MOVE
EAST TOWARDS NORTHWEST PENNSYLVANIA. VISIBILITIES IN SNOW RANGE FROM
MVFR TO BRIEF IFR...ESPECIALLY FARTHER TO THE NORTH. SNOW WILL
DIMINISH MOST AREAS BY 10Z AND CEILINGS MAY EVEN LIFT ABOVE 4K FEET
FOR A PERIOD OF TIME ON WEDNESDAY MORNING. A TROUGH DEEPENS OVER THE
AREA ON WEDNESDAY AFTERNOON WITH AN ARCTIC FRONT MOVING THROUGH
BRINGING A GOOD BURST OF SNOW TO MOST TAF SITES WEDNESDAY AFTERNOON
INTO WEDNESDAY EVENING. THE SNOW WILL LAST LONGEST WHERE BETTER
MOISTURE IS AVAILABLE AT THE EASTERN TAF SITES. BROUGHT IFR
VISIBILITIES INTO ALL SITES AS THE FRONT COMES THROUGH BUT COULD
DROP TO A HALF MILE OR LESS FOR A SHORT PERIOD. WESTERLY WINDS
WILL INCREASE AHEAD OF THE FRONT WITH GUSTS OF 20-25
KNOTS...SHIFTING TO NORTHWEST WITH THE FRONTAL PASSAGE.
.OUTLOOK...NON VFR LINGERING INTO WEDNESDAY EVENING THEN MAINLY
SNOWBELT THU. NON VFR CONDITIONS RETURN FRIDAY NIGHT AND CONTINUE
INTO SUNDAY.
&&
.MARINE...
THE NEXT ARCTIC FRONT WILL GRADUALLY TURN SW WINDS TO NW LATE
TONIGHT THRU WED NIGHT. A TROUGH HANGING BACK INTO THE EASTERN LAKES
WILL KEEP THE FLOW DISRUPTED ENOUGH TO KEEP SPEEDS MOSTLY IN A 10 TO
20 KNOT RANGE UNTIL THU WHEN 15 TO 25 KNOTS MAY BE MORE COMMON. HIGH
PRESSURE CROSSES OH ON FRI TO PRODUCE A LIGHT FLOW THEN WINDS BACK
TO THE SSW FOR FRI NIGHT INTO SAT AHEAD OF THE NEXT ARCTIC FRONT
THAT SHOULD CROSS THE LAKE SAT NIGHT VEERING THE WINDS BACK TO NW AT
10 TO 20 KNOTS FOR SUN.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KIELTYKA
NEAR TERM...MULLEN
SHORT TERM...KIELTYKA
LONG TERM...ADAMS
AVIATION...KEC
MARINE...ADAMS
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
732 PM EST THU FEB 19 2015
.SYNOPSIS...
BITTER COLD TEMPERATURES AND SUBZERO WIND CHILLS ARE EXPECTED
THROUGH FRIDAY MORNING. LOW PRESSURE DEVELOPING IN THE MISSISSIPPI
VALLEY ON FRIDAY WILL MOVE TO THE EAST FOR SATURDAY AND SUNDAY.
THIS WILL LEAD TO RISING TEMPERATURES THIS WEEKEND. BUT SNOW WILL
ARRIVE SATURDAY WHICH WILL PROBABLY CHANGE TO A WINTRY MIX OVER
SOUTHERN PENNSYLVANIA SATURDAY NIGHT.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
RADAR RETURNS HAVE BEEN RELAXING OVER PAST SEVERAL HOURS...WITH
POTENTIAL FOR SOME LIGHT ACCUMS NOW BASICALLY CONFINED TO THE NW
MTNS AND LAUREL HIGHLANDS. ELSEWHERE FLURRIES WILL BE IN AND OUT
WITH A LIGHT COATING POSS FOR NEXT SEVERAL HOURS. AFTER
THAT...LARGER BREAKS WILL BEGIN TO APPEAR IN CLOUD COVER WITH NEARLY
FULL CLEARING ANTICIPATED FOR MAJORITY OF THE AREA OVERNIGHT.
MAIN THREAT TONIGHT INTO FRI WILL BE DANGEROUS WIND CHILLS. WINDS
STAY QUITE BRISK THROUGH THE OVERNIGHT AS PRESSURE GRADIENT
REMAINS TIGHT...WITH TEMPERATURES EXPECTED TO BOTTOM OUT IN
VICINITY OF THE COLDEST OF THE YEAR /WHICH IS IMPRESSIVE AFTER
LAST COUPLE COLD SPELLS/. EXPECT MINS IN THE MID TEENS BELOW ZERO
IN THE NW MTNS /WHERE IT IS ALREADY -7F AT KBFD AT 00Z/ - WITH
WIND CHILLS THERE LIKELY DROPPING COLDER THAN 30 BELOW - ITS
ALREADY WELL INTO THE -20S FOR WC/S. SO NO BRAINER FOR WIND CHILL
WARNINGS N AND W / WITH ADVISORIES FURTHER TO THE SE. WIND CHILLS
SHOULD BE RISING WELL ENOUGH BY 10AM TO ALLOW THEM TO EXPIRE ON
TIME...BUT MAY REMAIN BELOW THRESHOLDS THROUGH THE
MORNING...MEANING THE WIND CHILL PRODS MAY NEED TO ME EXTENDED A
FEW HOURS.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH 6 PM FRIDAY/...
TEMPS DON/T WARM ALL THAT MUCH HIGHER THAN TODAY BUT THE WIND
SHOULD BE MUCH LESS OF A FACTOR. COLDEST PART OF THE TROUGH WILL
BE TO OUR EAST IN THE MORNING BUT THE SFC RIDGE AXIS WILL NOT
CREST OVERHEAD UNTIL LATE IN THE DAY. THUS...SOME CLOUDS COULD
DEVELOP AGAIN IN THE SOLAR MAXIMUM BUT THESE SHOULD NOT BE AS
WIDESPREAD AS ON THURSDAY.
&&
.LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...
AXIS OF LONGITUDINALLY BROAD UPPER TROF SWINGING THROUGH THE
EASTERN U.S. TODAY WILL ALLOW UPPER FLOW PATTERN TO TRANSITION
TO A WESTERLY THEN SOUTHWESTERLY FLOW BY THE WEEKEND. THE
FLATTENING OF THE UPPER FLOW OVER THE NORTHEAST THIS COMING
WEEKEND WILL LEAD TO A MODERATION AWAY FROM THE BITTER COLD WE
HAVE EXPERIENCED IN THE CURRENT PATTERN.
THE CENTER OF THIS NEXT ARCTIC HIGH MAY SLIDE JUST SOUTH OF THE
REGION FRIDAY NIGHT THEN OFF THE MID ATLANTIC COAST - PER THE 00Z
EC...WHILE THE GEFS WOULD SUGGEST A LITTLE MORE IN THE WAY OF LLVL
COLD AIR DAMMING OVER THE CWA...PRECEDING INCREASING MOISTURE AND
A WINTRY MIX OR SNOW SPREADING IN FROM THE SW...THEN ANOTHER PUSH
OF ARCTIC AIR FOR LATE SUNDAY AND MONDAY.
TEMPERATURES SUNDAY LOOK TO RISE WELL ABOVE THE FREEZING MARK
OVER A GOOD PART OF CENTRAL PA AS THE EARLIER MENTIONED MODERATION
IN THE UPPER FLOW IS FORECAST TO ARRIVE. THE NEXT SHORTWAVE
TROF/SFC FRONT IS ALSO CURRENTLY TIMED TO MOVE FROM THE MID MISS
VALLEY TO ERN GLAKES REGION THIS SATURDAY AND SUNDAY... LEADING TO
THE POSSIBILITY OF SNOW OR RAIN FOR A CHANGE OVER SRN PA AND SNOW
OVER THEN NORTH. LATEST MEDIUM RANGE GUIDANCE DEVELOPS A SFC LOW
ALONG THE FRONT...POSSIBLY MOVING ACROSS PA.
AS HIGH PRESSURE MOVES ACROSS THE REGION NEXT MONDAY AND TUESDAY
BEHIND SUNDAY`S POTENTIAL SYSTEM...DRY WEATHER IS EXPECTED WITH
TEMPS AGAIN RETURNING TO WELL BELOW NORMAL LEVELS.
GEFS AND OTHER OPERATIONAL MODELS TEMP HIGHLIGHT ANOTHER ARCTIC
OUTBREAK HEADED OUR WAY FOR EARLY NEXT WEEK. SEVERAL GEFS PLUMES
OF 2 METER TEMPS AND THEIR MEAN SUGGEST THAT IT COULD GET AS COLD
AS WHAT WE EXPECT FRIDAY TO SEE FRIDAY MORNING. HOWEVER...WITH
TEMPS ALOFT BEING MUCH HIGHER THAN THE EXTREME COLD AT 700-500
MB...UNLESS WE SEE SOME TYPE OF PERFECT TIMING OF A CLOUDY COLD
DAY...THEN CLEARING RIGHT AT SUNSET WITH CALM AIR...I EXPECT MAX
TEMPS MONDAY AND MINS TUESDAY MORNING TO BE SEVERAL DEG F OR MORE
WARMER THAN THIS CURRENT ARCTIC OUTBREAK.
SCATTERED SNOW SHOWERS WILL TAPER OFF THROUGH EARLY TUESDAY...THEN
INCREASE OVER THE MTNS WEDNESDAY AS ANOTHER PUSH OF ARCTIC AIR
ARRIVES A SHORTWAVE ON WED.
&&
.AVIATION /01Z FRIDAY THROUGH TUESDAY/...
MAIN AVIATION CONCERN EARLY THIS EVENING WILL BE CONTINUING SNOW
SHOWERS AFFECTING THE LAUREL HIGHLANDS. PLUME OF LK MICHIGAN
MOISTURE CAN BE SEEN IN RAP LOW LVL MOISTURE FIELDS ACROSS
SOUTHWEST PA. IFR/LIFR VSBYS REPORTED AT KJST AND KAOO AS OF 23Z.
HOWEVER...HRRR AND RADAR TRENDS SUGGEST MOISTURE PLUME AND ASSOC
SNOW SHOWERS WILL BE SHUNTED SOUTH OF KJST/KAOO BY 00Z-01Z.
FOR THE REST OF CENTRAL PA...DIURNAL CU SHOULD GIVE WAY TO
BREAKING CLOUDS OVERNIGHT...AS SUN SETS AND VERY DRY...ARCTIC AIR
OVERSPREADS THE AREA. HIGH CONFIDENCE OF WIDESPREAD VFR CONDS
LATER TONIGHT ACROSS MOST OF CENTRAL PA...AS ARCTIC HIGH PRES
BUILDS INTO THE REGION. HOWEVER...CONFIDENCE NOT QUITE AS HIGH AT
KBFD AND KJST...WHERE UPSLOPE FLOW INTO THE MTNS COULD STILL
CONCEIVABLY PRODUCE MVFR CIGS/OCNL -SHSN AT KBFD AND KJST THROUGH
THE NIGHT.
NEARLY CERTAIN IMPROVEMENT...EVEN AT KJST/KBFD...TO VFR CONDS
FRIDAY...AS HIGH PRES BUILDS INTO THE REGION.
OUTLOOK...
SAT...SNOW/LOW VSBYS LIKELY...MAINLY PM.
SUN...AM LOW CIGS/SHRASN LIKELY.
MON-TUE...NO SIG WX EXPECTED.
&&
.CLIMATE...
GOING FOR TEMPS TO GET DOWN TO RECORD MINS IN MANY PLACES
OVERNIGHT. THE TRICK WILL BE WITH THE WIND STAYING UP...IT MAY
STAY TOO WELL-MIXED AND THE DOWNSLOPE IN THE SE MIGHT HURT THE
RECORD CHANCES AS WELL. IPT IS THE LEAST LIKELY TO TIE/SET A
RECORD. HAVE GONE BELOW MOS AT MOST SITES EYEING A BIT OF A BIAS
TOWARD CLIMO IN THE MOS AND DECENT CLEARING. RECORDS FOR THE
20TH:
MDT 0 IN 1978 AND 1979
IPT -7 IN 1936
AOO 0 IN 1978
BFD -11 IN 1959
JST -9 IN 1978
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WIND CHILL WARNING UNTIL 10 AM EST FRIDAY FOR PAZ004>006-
010>012-017-018-024-033-037-041-042.
WIND CHILL ADVISORY UNTIL 10 AM EST FRIDAY FOR PAZ019-025>028-
034>036-045-046-049>053-056>059-063>066.
&&
$$
SYNOPSIS...DANGELO/RXR
NEAR TERM...DANGELO/RXR
SHORT TERM...DANGELO
LONG TERM...LAMBERT/GARTNER
AVIATION...FITZGERALD
CLIMATE...
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
615 PM EST THU FEB 19 2015
.SYNOPSIS...
BITTER COLD TEMPERATURES AND SUBZERO WIND CHILLS ARE EXPECTED
THROUGH FRIDAY MORNING. LOW PRESSURE DEVELOPING IN THE MISSISSIPPI
VALLEY ON FRIDAY WILL MOVE TO THE EAST FOR SATURDAY AND SUNDAY.
THIS WILL LEAD TO RISING TEMPERATURES THIS WEEKEND. BUT SNOW WILL
ARRIVE SATURDAY WHICH WILL PROBABLY CHANGE TO A WINTRY MIX OVER
SOUTHERN PENNSYLVANIA SATURDAY NIGHT.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
CLOSED CELLULAR CU NOW PREVAIL OVER CENTRAL PA. STILL SOME POCKETSOF
MODERATE CU DEVELOPMENT AND RADAR RETURNS. WE HAVE BEEN ABLE TO
SEE A TRAIN OF --SHSN ROLLING ALONG TUSSEY MTN THRU THE DAY. BUT
THEY ARE VERY BRIEF AND HOLD LITTLE CHANCE OF ANY ACCUMS.
NIGHTFALL SHOULD START TO MAKE LARGER BREAKS APPEAR AND NEARLY
FULL CLEARING IS ANTICIPATED FOR MUCH OF THE AREA OVERNIGHT. THE
WINDS WILL STAY UP AND THE WIND CHILLS WILL BE NASTY/DANGEROUS.
TEMPERATURES WILL BE SOME OF IF NOT THE VERY COLDEST OF THE YEAR.
EXPECT MINS IN THE MID TEENS BELOW ZERO IN THE NW MTNS - WHERE
WIND CHILLS WILL LIKELY BE COLDER THAN 30 BELOW. WILL HOLD ONTO
ALL WIND CHILL FLAGS AND TIMING. WIND CHILLS SHOULD BE RISING WELL
ENOUGH BY 10AM TO ALLOW THEM TO EXPIRE ON TIME...BUT THEY MAY STAY
TOO LOW FOR ANOTHER HR/TWO. WILL MENTION THIS TO EVENING SHIFT FOR
POSSIBLE REVIEW.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH 6 PM FRIDAY/...
TEMPS DON/T WARM ALL THAT MUCH HIGHER THAN TODAY BUT THE WIND
SHOULD BE MUCH LESS OF A FACTOR. COLDEST PART OF THE TROUGH WILL
BE TO OUR EAST IN THE MORNING BUT THE SFC RIDGE AXIS WILL NOT
CREST OVERHEAD UNTIL LATE IN THE DAY. THUS...SOME CLOUDS COULD
DEVELOP AGAIN IN THE SOLAR MAXIMUM BUT THESE SHOULD NOT BE AS
WIDESPREAD AS ON THURSDAY.
&&
.LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...
AXIS OF LONGITUDINALLY BROAD UPPER TROF SWINGING THROUGH THE
EASTERN U.S. TODAY WILL ALLOW UPPER FLOW PATTERN TO TRANSITION
TO A WESTERLY THEN SOUTHWESTERLY FLOW BY THE WEEKEND. THE
FLATTENING OF THE UPPER FLOW OVER THE NORTHEAST THIS COMING
WEEKEND WILL LEAD TO A MODERATION AWAY FROM THE BITTER COLD WE
HAVE EXPERIENCED IN THE CURRENT PATTERN.
THE CENTER OF THIS NEXT ARCTIC HIGH MAY SLIDE JUST SOUTH OF THE
REGION FRIDAY NIGHT THEN OFF THE MID ATLANTIC COAST - PER THE 00Z
EC...WHILE THE GEFS WOULD SUGGEST A LITTLE MORE IN THE WAY OF LLVL
COLD AIR DAMMING OVER THE CWA...PRECEDING INCREASING MOISTURE AND
A WINTRY MIX OR SNOW SPREADING IN FROM THE SW...THEN ANOTHER PUSH
OF ARCTIC AIR FOR LATE SUNDAY AND MONDAY.
TEMPERATURES SUNDAY LOOK TO RISE WELL ABOVE THE FREEZING MARK
OVER A GOOD PART OF CENTRAL PA AS THE EARLIER MENTIONED MODERATION
IN THE UPPER FLOW IS FORECAST TO ARRIVE. THE NEXT SHORTWAVE
TROF/SFC FRONT IS ALSO CURRENTLY TIMED TO MOVE FROM THE MID MISS
VALLEY TO ERN GLAKES REGION THIS SATURDAY AND SUNDAY... LEADING TO
THE POSSIBILITY OF SNOW OR RAIN FOR A CHANGE OVER SRN PA AND SNOW
OVER THEN NORTH. LATEST MEDIUM RANGE GUIDANCE DEVELOPS A SFC LOW
ALONG THE FRONT...POSSIBLY MOVING ACROSS PA.
AS HIGH PRESSURE MOVES ACROSS THE REGION NEXT MONDAY AND TUESDAY
BEHIND SUNDAY`S POTENTIAL SYSTEM...DRY WEATHER IS EXPECTED WITH
TEMPS AGAIN RETURNING TO WELL BELOW NORMAL LEVELS.
GEFS AND OTHER OPERATIONAL MODELS TEMP HIGHLIGHT ANOTHER ARCTIC
OUTBREAK HEADED OUR WAY FOR EARLY NEXT WEEK. SEVERAL GEFS PLUMES
OF 2 METER TEMPS AND THEIR MEAN SUGGEST THAT IT COULD GET AS COLD
AS WHAT WE EXPECT FRIDAY TO SEE FRIDAY MORNING. HOWEVER...WITH
TEMPS ALOFT BEING MUCH HIGHER THAN THE EXTREME COLD AT 700-500
MB...UNLESS WE SEE SOME TYPE OF PERFECT TIMING OF A CLOUDY COLD
DAY...THEN CLEARING RIGHT AT SUNSET WITH CALM AIR...I EXPECT MAX
TEMPS MONDAY AND MINS TUESDAY MORNING TO BE SEVERAL DEG F OR MORE
WARMER THAN THIS CURRENT ARCTIC OUTBREAK.
SCATTERED SNOW SHOWERS WILL TAPER OFF THROUGH EARLY TUESDAY...THEN
INCREASE OVER THE MTNS WEDNESDAY AS ANOTHER PUSH OF ARCTIC AIR
ARRIVES A SHORTWAVE ON WED.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
MAIN AVIATION CONCERN EARLY THIS EVENING WILL BE CONTINUING SNOW
SHOWERS AFFECTING THE LAUREL HIGHLANDS. PLUME OF LK MICHIGAN
MOISTURE CAN BE SEEN IN RAP LOW LVL MOISTURE FIELDS ACROSS
SOUTHWEST PA. IFR/LIFR VSBYS REPORTED AT KJST AND KAOO AS OF 23Z.
HOWEVER...NR TERM MDL DATA AND RADAR TRENDS SUGGEST MOISTURE PLUME
IS SHUNTED SOUTH OF KJST/KAOO BY 00Z-01Z...CAUSING SNOW TO TAPER
OFF.
FOR THE REST OF CENTRAL PA...DIURNAL CU SHOULD GIVE WAY TO
BREAKING CLOUDS OVERNIGHT...AS SUN SETS AND VERY DRY...ARCTIC AIR
OVERSPREADS THE AREA. HIGH CONFIDENCE OF WIDESPREAD VFR CONDS
LATER TONIGHT ACROSS MOST OF CENTRAL PA...AS ARCTIC HIGH PRES
BUILDS INTO THE REGION. HOWEVER...CONFIDENCE NOT QUITE AS HIGH AT
KBFD AND KJST...WHERE UPSLOPE FLOW INTO THE MTNS COULD STILL
CONCEIVABLY PRODUCE MVFR CIGS AT KBFD OR OCNL LGT SNOW AT KJST.
NEARLY CERTAIN IMPROVEMENT...EVEN AT KJST/KBFD...TO VFR CONDS
FRIDAY. HOWEVER...FAST MOVING SYSTEM FROM THE MS VALLEY WILL
BRING IN CLOUDS FRI NIGHT AND SNOW WILL MOVE IN FROM THE WEST THRU
THE DAY ON SAT.
SOME POTENTIAL FOR MORE IN THE WAY OF FREEZING RAIN BY SATURDAY
NIGHT ACROSS THE S/SE PORTION OF THE CWA AS THE TEMPS ALOFT WARM
ABOVE FREEZING...BUT THE POTENTIAL FOR SLEET OR FREEZING RAIN
COULD EXTEND INTO NORTHERN PA DEPENDING HOW STRONG THE SRLY LLJET
BECOMES. COLDER/DRIER AIR WORKS BACK INTO CENTRAL PA LATER SUNDAY
INTO MONDAY.
OUTLOOK...
SAT-SUN...IFR LKLY WITH SN N AND MIXED PCPN CENT AND S.
MON-TUE...BCMG VFR. NO SIG WX.
&&
.CLIMATE...
GOING FOR TEMPS TO GET DOWN TO RECORD MINS IN MANY PLACES
OVERNIGHT. THE TRICK WILL BE WITH THE WIND STAYING UP...IT MAY
STAY TOO WELL-MIXED AND THE DOWNSLOPE IN THE SE MIGHT HURT THE
RECORD CHANCES AS WELL. IPT IS THE LEAST LIKELY TO TIE/SET A
RECORD. HAVE GONE BELOW MOS AT MOST SITES EYEING A BIT OF A BIAS
TOWARD CLIMO IN THE MOS AND DECENT CLEARING. RECORDS FOR THE
20TH:
MDT 0 IN 1978 AND 1979
IPT -7 IN 1936
AOO 0 IN 1978
BFD -11 IN 1959
JST -9 IN 1978
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WIND CHILL WARNING UNTIL 10 AM EST FRIDAY FOR PAZ004>006-
010>012-017-018-024-033-037-041-042.
WIND CHILL ADVISORY UNTIL 10 AM EST FRIDAY FOR PAZ019-025>028-
034>036-045-046-049>053-056>059-063>066.
&&
$$
SYNOPSIS...DANGELO
NEAR TERM...DANGELO
SHORT TERM...DANGELO
LONG TERM...LAMBERT/GARTNER
AVIATION...DANGELO/FITZGERALD
CLIMATE...
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
359 PM EST WED FEB 18 2015
.SYNOPSIS...
AN ARCTIC FRONT AND POTENT UPPER LEVEL DISTURBANCE WILL BRING
SNOW SHOWERS OR EVEN A FEW HOUR PERIOD OF STEADIER SNOW TO THE
THIS AFTERNOON AND TONIGHT...WITH THE POTENTIAL FOR AN EXTENSIVE
NORTH- SOUTH BAND OF INTENSE...DANGEROUS SNOW SQUALLS MARCHING
ACROSS CENTRAL PENNSYLVANIA AND THE SUSQUEHANNA VALLEY THROUGH THE
LATE AFTERNOON AND EARLY EVENING. BITTER COLD TEMPERATURES AND
SUBZERO WIND CHILLS ARE EXPECTED TONIGHT...THROUGH THURSDAY AND INTO
FRIDAY MORNING.
A GRADUAL WARM-UP WILL OCCUR THIS COMING WEEKEND...BUT WITH IT
WILL COME A BOUT OF WINTRY WEATHER AS LOW PRESSURE ORGANIZES AND
MOVES NORTHEAST FROM THE MID MISSISSIPPI VALLEY TO THE EASTERN
GREAT LAKES REGION.
&&
.NEAR TERM /UNTIL 10 PM THIS EVENING/...
LATEST RADAR HAS BANDS OF INCREASED SNOWFALL MOVING THROUGH THE
CENTRAL MOUNTAINS AND SLOWLY PROGRESSING EASTWARD. THE LATEST
SHORT TERM HI RES MODELS AND 18Z OPERATIONAL GUIDANCE...CONTINUE
TO SHOW THE AMPLIFYING UPPER TROUGH AND A SIGNIFICANT AND RATHER
STG SHORTWAVE MOVE THROUGH CENTRAL PA THIS AFTERNOON AND SWING
THROUGH THE EASTERN HALF OF PA THIS EVENING. THIS FEATURE WILL
ALSO ACT TO ENHANCE LLVL CONVERGENCE AND DEEP LAYER INSTABILITY
ALONG AND JUST AHEAD OF THE CFROPA. A HIGHLY UNUSUAL /AND
ANOMALOUS/ NORTH- SOUTH RIBBON OF MIXED LAYER CAPE OF 50-150 J/KG
IS FORMING JUST AHEAD OF THE ARCTIC BOUNDARY THIS AFTERNOON NEAR
THE ALLEGHENY FRONT. LATEST HRRR IS CURRENTLY SLOWING THE WAVES
PROGRESS AND BREAKING APART THE LINE AS IT MOVES EASTWARD. LATEST
NAM12 SNOW SQUALL PARAMETERS SHOWING ISALLOBARIC EFFECTS ON
OVERALL WIND SPEED. FRONTAL PASSAGE STILL PROGGED AROUND 00Z.
FOLLOWING THIS FRONT...MID AND UPPER FLOW WILL BE NEARLY PARALLEL
SUPPORTING ANAFRONT-LIKE PRECIP IN THE FORM OF A FEW TO SVRL HOUR
PERIOD OF LIGHT TO MDT SNOW -MAINLY ACROSS THE NW HALF OF THE
STATE.
MOST PLACES ACROSS CENTRAL PENN SHOULD SEE 1-2 INCHES OVER THE
NEXT 24 HOURS...WITH THE MTNS OF NRN PENN PICKING UP 2-3 INCHES
AND THE LAURELS SEE AS MUCH AS 3-5 INCHES BY EARLY THURSDAY
MORNING. A WINTER WEATHER ADVISORY CONTINUES FOR THE LAURELS TO
MIDNIGHT TONIGHT.
AS THE ARCTIC FRONT DROPS THROUGH THIS EVENING EXPECT GUSTY
NORTHWEST FLOW DEVELOPING LATE TODAY AND TONIGHT AND WIND CHILLS
WILL BECOME A FACTOR.
&&
.SHORT TERM /10 PM THIS EVENING THROUGH 6 PM THURSDAY/...
WIND CHILL WARNINGS TONIGHT...BEGINNING AT MIDNIGHT FOR ALL OF
THE WESTERN AND NRN MTNS...WHILE WIND CHILL ADVISORIES WERE ISSUED
ELSEWHERE. THESE WIND CHILL PRODUCTS CONTINUE RIGHT THROUGH 15Z
FRIDAY AS THE COLD AIR MASS WILL MOVE OVER AND SIT OVER THE REGION
THROUGH FRIDAY.
LOWS TONIGHT BE AROUND -5 TO -10F ACROSS THE NW MTNS...TO THE
SINGLE DIGITS ABOVE ZERO THROUGH CENTRAL PA...TO NEAR 10F IN THE
SE.
HIGHS THURSDAY WILL STRUGGLE TO CLIMB ABOVE ZERO IN THE NW MTNS
/AND STAY JUST IN THE SINGLE DIGITS TO TEENS ELSEWHERE/ WITH
CONTINUED GUSTY NW WINDS UP TO 30-35 MPH AND OCNL FLURRIES AND
BANDS OF SNOW SHOWERS. THE SNOW SHOWERS COULD ADD ANOTHER COATING
TO 1/2 INCH IN THE CENTRAL RIDGE AND VALLEY REGION...AND ANOTHER
INCH POSSIBLE IN THE ALLEGHANIES.
&&
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
AXIS OF LONGITUDINALLY BROAD UPPER TROF COVERING THE CONUS EAST
OF THE ROCKIES AT THE START OF THE LONG TERM PERIOD IS FORECAST
TO SHIFT EAST AND TRANSITION THE UPPER FLOW TO A ZONAL PATTERN BY
THE WEEKEND. CORE OF ARCTIC AIR ALOFT IS FORECAST TO DROP INTO NRN
PA THURSDAY AFTN/EVE...SUPPORTING THE SHIFT IN THE UPPER FLOW. IN
RESPONSE TO ADDITIONAL COLD AIR/ENERGY DROPPING SOUTH ALONG THE
FRONT RANGE OVER THE WEEKEND...THE UPPER FLOW OVER THE EAST IS
FORECAST TO TURN SWRLY INTO NEXT WEEK. AS A RESULT...VERY COLD
AIR WILL CONTINUE TO IMPACT THE REGION THROUGH AT LEAST THE REST
OF THE WORK-WEEK.
THE FLATTENING OF THE UPPER FLOW OVER THE NORTHEAST THIS COMING
WEEKEND WILL LEAD TO A MODERATION AWAY FROM THE BITTER COLD WE
HAVE EXPERIENCED IN THE CURRENT PATTERN.
THE CENTER OF THIS NEXT ARCTIC HIGH MAY SLIDE JUST SOUTH OF THE
REGION THEN OFF THE MID ATLANTIC COAST - PER THE 00Z EC...WHILE
THE GEFS WOULD SUGGEST A LITTLE MORE IN THE WAY OF LLVL COLD AIR
DAMMING OVER THE CWA...PRECEDING INCREASING MOISTURE AND A WINTRY
MIX OR SNOW SPREADING IN FROM THE SW...THEN ANOTHER PUSH OF
ARCTIC AIR FOR LATE SUNDAY AND MONDAY.
TEMPERATURES SUNDAY LOOK TO RISE WELL ABOVE THE FREEZING MARK
OVER A GOOD PART OF CENTRAL PA AS THE EARLIER MENTIONED MODERATION
IN THE UPPER FLOW IS FORECAST TO ARRIVE. THE NEXT SHORTWAVE
TROF/SFC FRONT IS ALSO CURRENTLY TIMED TO MOVE FROM THE MID MISS
VALLEY TO ERN GLAKES REGION THIS SATURDAY AND SUNDAY... LEADING TO
THE POSSIBILITY OF SNOW OR RAIN FOR A CHANGE OVER SRN PA AND SNOW
OVER THEN NORTH. LATEST RUNS OF MDM RANGE GUIDANCE NOW DEVELOPS A
SFC LOW ALONG THE FRONT...POSSIBLY MOVING ACROSS PA. HAVE
INCREASED POPS...QPF AND POTENTIAL FOR A MESSY WINTER WEATHER
EVENT MAINLY DURING THE DAY SUNDAY.
AS HIGH PRESSURE MOVES ACROSS THE REGION NEXT MONDAY AND TUESDAY
BEHIND SUNDAY`S POTENTIAL SYSTEM...DRY WEATHER IS EXPECTED WITH
TEMPS AGAIN RETURNING BELOW NORMAL...BUT NOT AS FAR BELOW AS IN
RECENT DAYS. SCATTERED SNOW SHOWERS WILL TAPER OFF THROUGH EARLY
TUESDAY...THEN INCREASE OVER THE MTNS WEDNESDAY AS ANOTHER PUSH OF
ARCTIC AIR ARRIVES A SHORTWAVE ON WED.
&&
.AVIATION /21Z WEDNESDAY THROUGH MONDAY/...
IFR AND LOWER CIGS AND VSBYS FROM FROM THE BEFORE MENTIONED TROUGH
AND ASSOCIATED SNOW SQUALLS AND SHOWERS WILL CONTINUE THROUGH 00Z. SHSN
SHOULD EVENTUALLY REACH INTO THE ERN AIRFIELDS WITH MVFR/IFR
RESTRICTIONS EXPECTED BETWEEN 21Z TO 00Z. INTENSE SNOW SQUALLS
WILL ACCOMPANY THE ARCTIC FROPA AND IS RESULTING IN RAPID DROP IN
VISBYS AOB 1/2SM. HAVE INCLUDED 1HR TEMPO OF 1/4 TO 1/2SM VISBYS
BASED ON THE LATEST HRRR AND NAM. SFC WINDS INITIALLY FROM
200-230 DEGREES WILL SHIFT TO 270-300 BEHIND THE FRONT WITH GUSTS
15-25MPH. PROLONGED IFR EXPECTED AT BFD/JST WITH COLD NW UPSLOPE
FLOW SHSN CONTINUING TONIGHT.
CONDITIONS WILL SLOWLY IMPROVE LATE TONIGHT INTO TOMORROW
MORNING...WITH VSBYS LIFTING BETWEEN 02Z TO 06Z...AT ALL TAF
SITES AND CIGS SLOWLY LIFTING TOWARDS MORNING.
OUTLOOK...
THU...MVFR/IFR -SHSN WRN 1/3. MAINLY VFR CENTRAL AND ERN TAFS.
FRI...BCMG VFR. NO SIG WX.
SAT-SUN...MVFR/IFR LKLY WITH MIXED PCPN.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WIND CHILL WARNING FROM MIDNIGHT TONIGHT TO 10 AM EST FRIDAY
FOR PAZ004>006-010>012-017-018-024-033-037-041-042.
WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 10 AM EST FRIDAY
FOR PAZ019-025>028-034>036-045-046-049>053-056>059-063>066.
WINTER WEATHER ADVISORY UNTIL NOON EST THURSDAY FOR PAZ024-033.
&&
$$
SYNOPSIS...LAMBERT
NEAR TERM...LAMBERT/CERU
SHORT TERM...LAMBERT
LONG TERM...LAMBERT/GARTNER
AVIATION...CERU/STEINBUGL
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
347 PM EST WED FEB 18 2015
.SYNOPSIS...
AN ARCTIC FRONT AND POTENT UPPER LEVEL DISTURBANCE WILL BRING
SNOW SHOWERS OR EVEN A FEW HOUR PERIOD OF STEADIER SNOW TO THE
THIS AFTERNOON AND TONIGHT...WITH THE POTENTIAL FOR AN EXTENSIVE
NORTH- SOUTH BAND OF INTENSE...DANGEROUS SNOW SQUALLS MARCHING
ACROSS CENTRAL PENNSYLVANIA AND THE SUSQUEHANNA VALLEY THROUGH THE
LATE AFTERNOON AND EARLY EVENING. BITTER COLD TEMPERATURES AND
SUBZERO WIND CHILLS ARE EXPECTED TONIGHT...THROUGH THURSDAY AND INTO
FRIDAY MORNING.
A GRADUAL WARM-UP WILL OCCUR THIS COMING WEEKEND...BUT WITH IT
WILL COME A BOUT OF WINTRY WEATHER AS LOW PRESSURE ORGANIZES AND
MOVES NORTHEAST FROM THE MID MISSISSIPPI VALLEY TO THE EASTERN
GREAT LAKES REGION.
&&
.NEAR TERM /UNTIL 10 PM THIS EVENING/...
LATEST RADAR HAS BANDS OF INCREASED SNOWFALL MOVING THROUGH THE
CENTRAL MOUNTAINS AND SLOWLY PROGRESSING EASTWARD. THE LATEST
SHORT TERM HI RES MODELS AND 18Z OPERATIONAL GUIDANCE...CONTINUE
TO SHOW THE AMPLIFYING UPPER TROUGH AND A SIGNIFICANT AND RATHER
STG SHORTWAVE MOVE THROUGH CENTRAL PA THIS AFTERNOON AND SWING
THROUGH THE EASTERN HALF OF PA THIS EVENING. THIS FEATURE WILL
ALSO ACT TO ENHANCE LLVL CONVERGENCE AND DEEP LAYER INSTABILITY
ALONG AND JUST AHEAD OF THE CFROPA. A HIGHLY UNUSUAL /AND
ANOMALOUS/ NORTH- SOUTH RIBBON OF MIXED LAYER CAPE OF 50-150 J/KG
IS FORMING JUST AHEAD OF THE ARCTIC BOUNDARY THIS AFTERNOON NEAR
THE ALLEGHENY FRONT. LATEST HRRR IS CURRENTLY SLOWING THE WAVES
PROGRESS AND BREAKING APART THE LINE AS IT MOVES EASTWARD. LATEST
NAM12 SNOW SQUALL PARAMETERS SHOWING ISALLOBARIC EFFECTS ON
OVERALL WIND SPEED. FRONTAL PASSAGE STILL PROGGED AROUND 00Z.
FOLLOWING THIS FRONT...MID AND UPPER FLOW WILL BE NEARLY PARALLEL
SUPPORTING ANAFRONT-LIKE PRECIP IN THE FORM OF A FEW TO SVRL HOUR
PERIOD OF LIGHT TO MDT SNOW -MAINLY ACROSS THE NW HALF OF THE
STATE.
MOST PLACES ACROSS CENTRAL PENN SHOULD SEE 1-2 INCHES OVER THE
NEXT 24 HOURS...WITH THE MTNS OF NRN PENN PICKING UP 2-3 INCHES
AND THE LAURELS SEE AS MUCH AS 3-5 INCHES BY EARLY THURSDAY
MORNING. A WINTER WEATHER ADVISORY CONTINUES FOR THE LAURELS TO
MIDNIGHT TONIGHT.
AS THE ARCTIC FRONT DROPS THROUGH THIS EVENING EXPECT GUSTY
NORTHWEST FLOW DEVELOPING LATE TODAY AND TONIGHT AND WIND CHILLS
WILL BECOME A FACTOR.
&&
.SHORT TERM /10 PM THIS EVENING THROUGH 6 PM THURSDAY/...
WIND CHILL WARNINGS TONIGHT...BEGINNING AT MIDNIGHT FOR ALL OF
THE WESTERN AND NRN MTNS...WHILE WIND CHILL ADVISORIES WERE ISSUED
ELSEWHERE. THESE WIND CHILL PRODUCTS CONTINUE RIGHT THROUGH 15Z
FRIDAY AS THE COLD AIR MASS WILL MOVE OVER AND SIT OVER THE REGION
THROUGH FRIDAY.
LOWS TONIGHT BE AROUND -5 TO -10F ACROSS THE NW MTNS...TO THE
SINGLE DIGITS ABOVE ZERO THROUGH CENTRAL PA...TO NEAR 10F IN THE
SE.
HIGHS THURSDAY WILL STRUGGLE TO CLIMB ABOVE ZERO IN THE NW MTNS
/AND STAY JUST IN THE SINGLE DIGITS TO TEENS ELSEWHERE/ WITH
CONTINUED GUSTY NW WINDS UP TO 30-35 MPH AND OCNL FLURRIES AND
BANDS OF SNOW SHOWERS. THE SNOW SHOWERS COULD ADD ANOTHER COATING
TO 1/2 INCH IN THE CENTRAL RIDGE AND VALLEY REGION...AND ANOTHER
INCH POSSIBLE IN THE ALLEGHANIES.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
AXIS OF LONGITUDINALLY BROAD UPPER TROF COVERING THE CONUS EAST
OF THE ROCKIES AT THE START OF THE LONG TERM PERIOD IS FORECAST
TO SHIFT EAST AND TRANSITION THE UPPER FLOW TO A ZONAL PATTERN BY
THE WEEKEND. CORE OF ARCTIC AIR ALOFT IS FORECAST TO DROP INTO NRN
PA THURSDAY AFTN/EVE...SUPPORTING THE SHIFT IN THE UPPER FLOW. IN
RESPONSE TO ADDITIONAL COLD AIR/ENERGY DROPPING SOUTH ALONG THE
FRONT RANGE OVER THE WEEKEND...THE UPPER FLOW OVER THE EAST IS
FORECAST TO TURN SWRLY INTO NEXT WEEK. AS A RESULT...VERY COLD
AIR WILL CONTINUE TO IMPACT THE REGION THROUGH AT LEAST THE REST
OF THE WORK-WEEK.
THE FLATTENING OF THE UPPER FLOW OVER THE NORTHEAST THIS COMING
WEEKEND WILL LEAD TO A MODERATION AWAY FROM THE BITTER COLD WE
HAVE EXPERIENCED IN THE CURRENT PATTERN.
THE CENTER OF THIS NEXT ARCTIC HIGH MAY SLIDE JUST SOUTH OF THE
REGION THEN OFF THE MID ATLANTIC COAST - PER THE 00Z EC...WHILE
THE GEFS WOULD SUGGEST A LITTLE MORE IN THE WAY OF LLVL COLD AIR
DAMMING OVER THE CWA...PRECEDING INCREASING MOISTURE AND A WINTRY
MIX OR SNOW SPREADING IN FROM THE SW...THEN ANOTHER PUSH OF
ARCTIC AIR FOR LATE SUNDAY AND MONDAY.
TEMPERATURES SUNDAY HOLD THE POTENTIAL TO RISE ABOVE THE FREEZING
MARK OVER A GOOD PART OF CENTRAL PA AS THE EARLIER MENTIONED
MODERATION IN THE UPPER FLOW IS FORECAST TO ARRIVE. THE NEXT
SHORTWAVE TROF/SFC FRONT IS ALSO CURRENTLY TIMED TO MOVE FROM THE
MID MISS VALLEY TO ERN GLAKES REGION THIS SATURDAY AND SUNDAY...
LEADING TO THE POSSIBILITY OF SNOW OR RAIN FOR A CHANGE OVER SRN
PA AND SNOW OVER THEN NORTH.
AS HIGH PRESSURE MOVES ACROSS THE REGION NEXT MONDAY AND TUESDAY
BEHIND SUNDAY`S POTENTIAL FROPA...DRY WEATHER IS EXPECTED WITH
TEMPS AGAIN RETURNING BELOW NORMAL...BUT NOT AS FAR BELOW AS IN
RECENT DAYS.
&&
.AVIATION /20Z WEDNESDAY THROUGH MONDAY/...
IFR AND LOWER CIGS AND VSBYS FROM FROM THE BEFORE MENTIONED TROUGH
AND ASSOCIATED SNOW SQUALLS AND SHOWERS WILL CONTINUE THROUGH 00Z. SHSN
SHOULD EVENTUALLY REACH INTO THE ERN AIRFIELDS WITH MVFR/IFR
RESTRICTIONS EXPECTED BETWEEN 21Z TO 00Z. INTENSE SNOW SQUALLS
WILL ACCOMPANY THE ARCTIC FROPA AND IS RESULTING IN RAPID DROP IN
VISBYS AOB 1/2SM. HAVE INCLUDED 1HR TEMPO OF 1/4 TO 1/2SM VISBYS
BASED ON THE LATEST HRRR AND NAM. SFC WINDS INITIALLY FROM
200-230 DEGREES WILL SHIFT TO 270-300 BEHIND THE FRONT WITH GUSTS
15-25MPH. PROLONGED IFR EXPECTED AT BFD/JST WITH COLD NW UPSLOPE
FLOW SHSN CONTINUING TONIGHT.
CONDITIONS WILL SLOWLY IMPROVE LATE TONIGHT INTO TOMORROW
MORNING...WITH VSBYS LIFTING BETWEEN 02Z TO 06Z...AT ALL TAF
SITES AND CIGS SLOWLY LIFTING TOWARDS MORNING.
OUTLOOK...
THU...MVFR/IFR -SHSN WRN 1/3. MAINLY VFR CENTRAL AND ERN TAFS.
FRI...BCMG VFR. NO SIG WX.
SAT-SUN...MVFR/IFR LKLY WITH MIXED PCPN.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WIND CHILL WARNING FROM MIDNIGHT TONIGHT TO 10 AM EST FRIDAY
FOR PAZ004>006-010>012-017-018-024-033-037-041-042.
WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 10 AM EST FRIDAY
FOR PAZ019-025>028-034>036-045-046-049>053-056>059-063>066.
WINTER WEATHER ADVISORY UNTIL NOON EST THURSDAY FOR PAZ024-033.
&&
$$
SYNOPSIS...LAMBERT
NEAR TERM...LAMBERT/CERU
SHORT TERM...LAMBERT
LONG TERM...LAMBERT/GARTNER
AVIATION...CERU/STEINBUGL
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1017 AM EST WED FEB 18 2015
.SYNOPSIS...
AN ARCTIC FRONT AND POTENT UPPER LEVEL DISTURBANCE WILL BRING
SNOW SHOWERS OR EVEN A FEW HOUR PERIOD OF STEADIER SNOW TO THE
AREA TODAY INTO TONIGHT...WITH THE POTENTIAL FOR AN EXTENSIVE
NORTH-SOUTH BAND OF INTENSE...DANGEROUS SNOW SQUALLS MARCHING
ACROSS CENTRAL PENNSYLVANIA AND THE SUSQUEHANNA VALLEY LATER THIS
AFTERNOON AND EVENING. BITTER COLD TEMPERATURES AND SUBZERO WIND
CHILLS ARE EXPECTED TONIGHT...RIGHT INTO FRIDAY MORNING.
A GRADUAL WARM-UP WILL OCCUR THIS COMING WEEKEND...BUT WITH IT
WILL COME A BOUT OF WINTRY WEATHER AS LOW PRESSURE ORGANIZES AND
MOVES NORTHEAST FROM THE MID MISSISSIPPI VALLEY TO THE EASTERN
GREAT LAKES REGION.
&&
.NEAR TERM /UNTIL 10 PM THIS EVENING/...
CLEARING SKIES AND CALM WINDS GREET US THIS MORNING AS ONLY MID TO
HIGH LEVEL CLOUDS REMAIN OVER MOST OF PA. CLOUDS WILL THICKEN
FROM THE WEST AS THE MORNING CONTINUES WITH INCREASING CHANCES OF
LIGHT SNOW SHOWERS FROM THE WEST CENTRAL MOUNTAINS TO THE
NORTHWEST MTNS. LIGHT SNOW HAS BEGUN IN THE NORTHWEST AND OVER THE
LAURELS...AND PRECIPITATION CHANCES WILL INCREASE AS THE DAY
CONTINUES.
THE SITUATION FOR TODAY LOOKING QUITE SIMILAR IN MANY WAYS TO
WHAT WE EXPERIENCED IN TERMS OF SNOW SQUALLS WITH THE LAST ARCTIC
FRONT ON SATURDAY.
LATEST...SHORT TERM MODELS AND 12Z OPERATIONAL GUIDANCE...ALONG
WITH HIGH RES MODELS CONTINUE TO SHOW THE AMPLIFYING UPPER TROUGH
TAKING ON A SLIGHT NEG TILT AS IT SWINGS THROUGH THE GLAKES AND
UPPER OHIO RIVER VALLEY...WITH RAPIDLY ERODING STABILITY
ACCOMPANYING THE FRONT AS IT ENTERS THE REGION.
A SIGNIFICANT AND RATHER STG SHORTWAVE WILL MOVE NE UP THE OHIO
RIVER VALLEY. THIS FEATURE WILL ALSO ACT TO ENHANCE LLVL
CONVERGENCE AND DEEP LAYER INSTABILITY ALONG AND JUST AHEAD OF
THE CFROPA. A HIGHLY UNUSUAL /AND ANOMALOUS/ NORTH-SOUTH RIBBON OF
MIXED LAYER CAPE OF 50-150 J/KG WILL FORM JUST AHEAD OF THE ARCTIC
BOUNDARY THIS AFTERNOON NEAR THE ALLEGHENY FRONT. LATEST HRRR IS
CURRENTLY SLOWING THE WAVES PROGRESS AND BREAKING APART THE LINE
AS IT MOVES EASTWARD. LATEST NAM12 SNOW SQUALL PARAMETERS SHOWING
ISALLOBARIC EFFECTS ON OVERALL WIND SPEED. FRONTAL PASSAGE STILL
PROGGED AROUND 00Z.
THE LINE OF SQUALLS IS EXPECTED TO BE NEAR A KELZ TO KUNV AND
KAOO LINE BETWEEN 21-00Z...THEN OVER THE SUSQ VALLEY AROUND
00-02Z. BRIEF PERIODS OF SUB 1/4SM SQUALLS ARE POSSIBLE AT THE
HEIGHT OF THE SYSTEM AS IT PUSHES EAST ACROSS THE REGION THIS
AFTERNOON AND EARLY THIS EVENING.
FOLLOWING THIS FRONT...MID AND UPPER FLOW WILL BE NEARLY PARALLEL
SUPPORTING ANAFRONT-LIKE PRECIP IN THE FORM OF A FEW TO SVRL HOUR
PERIOD OF LIGHT TO MDT SNOW -MAINLY ACROSS THE NW HALF OF THE
STATE.
MOST PLACES ACROSS CENTRAL PENN SHOULD SEE 1-2 INCHES OVER THE
NEXT 24 HOURS...WITH THE MTNS OF NRN PENN PICKING UP 2-3 INCHES
AND THE LAURELS SEE AS MUCH AS 3-5 INCHES BY EARLY THURSDAY
MORNING. A WINTER WEATHER ADVISORY WAS ISSUED FOR THE LAURELS /AND
COLLABORATED WITH SURROUNDING WFOS/ FROM NOON TODAY TO MIDNIGHT
TONIGHT.
THE CLEARING SKIES SHOULD HELP TO WARM TEMPS THIS
AFTERNOON...THOUGH THE REMAINING HIGH CLOUDS WILL REDUCE INCOMING
RADIATION. STILL EXPECT TEMPS IN THE LOWER TO MID TEENS ACROSS
THE WEST AND THE LOW- MID 20S ACROSS THE CENTRAL AND SERN PENN
VALLEYS...BEFORE FALLING STEADILY IN THE WAKE OF THE ARCTIC FRONT.
AS THE ARCTIC FRONT DROPS THROUGH THIS EVENING EXPECT GUSTY
NORTHWEST FLOW DEVELOPING LATER TODAY AND TONIGHT AND WIND CHILLS
WILL BECOME A FACTOR.
&&
.SHORT TERM /10 PM THIS EVENING THROUGH 6 PM THURSDAY/...
WIND CHILL WARNINGS TONIGHT...BEGINNING AT MIDNIGHT FOR ALL OF
THE WESTERN AND NRN MTNS...WHILE WIND CHILL ADVISORIES WERE ISSUED
ELSEWHERE. THESE WIND CHILL PRODUCTS CONTINUE RIGHT THROUGH 15Z
FRIDAY AS THE COLD AIR MASS WILL MOVE OVER AND SIT OVER THE REGION
THROUGH FRIDAY.
LOWS TONIGHT WILL RANGE FROM -5 TO -10F ACROSS THE NW MTNS...TO
THE SINGLE DIGITS ABOVE ZERO IN THE SE.
HIGHS THURSDAY WILL STRUGGLE TO CLIMB ABOVE ZERO IN THE NW MTNS
/AND STAY JUST IN THE SINGLE DIGITS TO TEENS ELSEWHERE/ WITH
CONTINUED GUSTY NW WINDS UP TO 30-35 MPH AND OCNL FLURRIES AND
BANDS OF SNOW SHOWERS. THE SNOW SHOWERS COULD ADD ANOTHER COATING
TO 1/2 INCH IN THE CENTRAL RIDGE AND VALLEY REGION...AND 1-2
INCHES ACROSS THE ALLEGHENIES.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
AXIS OF LONGITUDINALLY BROAD UPPER TROF COVERING THE CONUS EAST
OF THE ROCKIES AT THE START OF THE LONG TERM PERIOD IS FORECAST
TO SHIFT EAST AND TRANSITION THE UPPER FLOW TO A ZONAL PATTERN BY
THE WEEKEND. CORE OF ARCTIC AIR ALOFT IS FORECAST TO DROP INTO NRN
PA THURSDAY AFTN/EVE...SUPPORTING THE SHIFT IN THE UPPER FLOW. IN
RESPONSE TO ADDITIONAL COLD AIR/ENERGY DROPPING SOUTH ALONG THE
FRONT RANGE OVER THE WEEKEND...THE UPPER FLOW OVER THE EAST IS
FORECAST TO TURN SWRLY INTO NEXT WEEK. AS A RESULT...VERY COLD
AIR WILL CONTINUE TO IMPACT THE REGION THROUGH AT LEAST THE REST
OF THE WORK-WEEK.
THE FLATTENING OF THE UPPER FLOW OVER THE NORTHEAST THIS COMING
WEEKEND WILL LEAD TO A MODERATION AWAY FROM THE BITTER COLD WE
HAVE EXPERIENCED IN THE CURRENT PATTERN.
THE CENTER OF THIS NEXT ARCTIC HIGH MAY SLIDE JUST SOUTH OF THE
REGION THEN OFF THE MID ATLANTIC COAST - PER THE 00Z EC...WHILE
THE GEFS WOULD SUGGEST A LITTLE MORE IN THE WAY OF LLVL COLD AIR
DAMMING OVER THE CWA...PRECEDING INCREASING MOISTURE AND A WINTRY
MIX OR SNOW SPREADING IN FROM THE SW...THEN ANOTHER PUSH OF
ARCTIC AIR FOR LATE SUNDAY AND MONDAY.
TEMPERATURES SUNDAY HOLD THE POTENTIAL TO RISE ABOVE THE FREEZING
MARK OVER A GOOD PART OF CENTRAL PA AS THE EARLIER MENTIONED
MODERATION IN THE UPPER FLOW IS FORECAST TO ARRIVE. THE NEXT
SHORTWAVE TROF/SFC FRONT IS ALSO CURRENTLY TIMED TO MOVE FROM THE
MID MISS VALLEY TO ERN GLAKES REGION THIS SATURDAY AND SUNDAY...
LEADING TO THE POSSIBILITY OF SNOW OR RAIN FOR A CHANGE OVER SRN
PA AND SNOW OVER THEN NORTH.
AS HIGH PRESSURE MOVES ACROSS THE REGION NEXT MONDAY AND TUESDAY
BEHIND SUNDAY`S POTENTIAL FROPA...DRY WEATHER IS EXPECTED WITH
TEMPS AGAIN RETURNING BELOW NORMAL...BUT NOT AS FAR BELOW AS IN
RECENT DAYS.
&&
.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
MAINLY VFR CONDS THIS MORNING...THOUGH IFR FROM SNOWFALL HAS
OVERTAKEN BFD...AND THE LIGHT WINDS AND HZ IS CAUSING MVFR VSBYS
AT LNS. ANY PREDOMINATELY VFR CONDITIONS WILL TREND TO THE
DOWNSIDE WITH HIGH CONFIDENCE IN IFR/MVFR BY THE AFTERNOON OVER
THE WRN AND CNTRL TAFS...CORRESPONDING TO AN UPTICK IN SHSN
COVERAGE AND INTENSITY AS AN ARCTIC FRONT MOVES THROUGH THE
AIRSPACE. SHSN SHOULD EVENTUALLY REACH INTO THE ERN AIRFIELDS WITH
MVFR/IFR RESTRICTIONS EXPECTED LATE THIS AFTN INTO EARLY EVENING.
LLVL INSTABILITY WITH STEEP LAPSE RATES SUGGESTS A BAND OF BRIEFLY
INTENSE SNOW SQUALLS WILL ACCOMPANY THE ARCTIC FROPA WHICH MAY
RESULT IN RAPID DROP IN VISBYS AOB 1/2SM. HAVE INCLUDED 1HR TEMPO
OF 1/4 TO 1/2SM VISBYS BASED ON THE LATEST HRRR. SFC WINDS
INITIALLY FROM 200-230 DEGREES WILL SHIFT TO 270-300 BEHIND THE
FRONT WITH GUSTS 15-25MPH. PROLONGED IFR EXPECTED AT BFD/JST WITH
COLD NW UPSLOPE FLOW SHSN CONTINUING TONIGHT.
OUTLOOK...
THU...MVFR/IFR -SHSN WRN 1/3. MAINLY VFR CENTRAL AND ERN TAFS.
FRI...BCMG VFR. NO SIG WX.
SAT-SUN...MVFR/IFR LKLY WITH MIXED PCPN.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WIND CHILL WARNING FROM MIDNIGHT TONIGHT TO 10 AM EST FRIDAY
FOR PAZ004>006-010>012-017-018-024-033-037-041-042.
WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 10 AM EST FRIDAY
FOR PAZ019-025>028-034>036-045-046-049>053-056>059-063>066.
WINTER WEATHER ADVISORY UNTIL NOON EST THURSDAY FOR PAZ024-033.
&&
$$
SYNOPSIS...LAMBERT
NEAR TERM...LAMBERT/CERU
SHORT TERM...LAMBERT
LONG TERM...LAMBERT/GARTNER
AVIATION...CERU/STEINBUGL
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
918 PM CST THU FEB 19 2015
.UPDATE...
ISSUED AT 912 PM CST THU FEB 19 2015
WILL CONTINUE TO CUT BACK POPS TONIGHT...AS DRY AIR NOT BEING
OVERCOME. WILL BE HARD TO GET MUCH MORE THAN A PERIOD OF SCATTERED
FLURRIES. IF ANYONE WILL BE ABLE TO SQUEAK OUT A FEW TENTHS IT
WILL PROBABLY BE OUR FAR EASTERN COUNTIES FROM MARSHALL TO
SPENCER.
WILL BE INTERESTING TO SEE WHAT HAPPENS TOMORROW. SHOULD BE A
WARM DAY WITH WARMING TEMPERATURES ALOFT AND GOOD MIXING. HOWEVER
WILL HAVE TO WATCH THE ABUNDANCE OF STRATUS CURRENTLY SEEN OVER
NORTH DAKOTA AND SOUTHERN CANADA. THE RAP HAS A DECENT HANDLE ON
THIS AND SUGGESTS IT WILL MOVE SOUTH INTO THE NORTHEAST HALF OF
OUR CWA TOMORROW. IF THIS WERE TO HAPPEN IT WOULD LIKELY HOLD
TEMPERATURES DOWN QUITE A BIT. WILL NOT MAKE ANY CHANGES NOW...BUT
SOMETHING FOR THE OVERNIGHT SHIFT TO MORE CLOSELY EXAMINE.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 330 PM CST THU FEB 19 2015
WARM FRONT IS PRESSING EASTWARD AT THIS TIME. IN FACT CHAMBERLAIN IS
UP CLOSE TO 30 DEGREES WITH WINNER AT 34 MID THURSDAY AFTERNOON. IN
THE NEAR TERM AND FOR TONIGHT...BELIEVE THAT MANY GUIDANCE VALUES
ARE TOO COLD...IN SOME CASES WAY TOO COLD. NOT SURE WHY TEMPERATURES
WOULD PLUMMET ALL THAT MUCH WITH THIS KIND OF SOUTHERLY FLOW AND THE
WARM FRONT NOT STALLING. THEREFORE TRENDED TOWARD THE WARMER
READINGS WHICH WERE RAW ECMWF VALUES BLENDED WITH MOS CONSENSUS. NOW
ONTO THE WARM FRONTAL SNOW...WHICH HAS SO FAR BEEN TOTALLY NON
EXISTENT IN OUR WESTERN ZONES. BONE DRY AIR IN THE LOW LEVELS...
WITNESSED BY CURRENT SURFACE DEW POINT READINGS STILL HOVER NEAR
ZERO AND SINGLE DIGITS BELOW ZERO ALONG AND EAST OF THE JAMES RIVER
VALLEY...HAS NOT ALLOWED ANYTHING TO REACH THE GROUND. SOME LOW
LEVEL MOISTURE RETURN MAY INCREASE GENERALLY EAST OF I 29 THIS
EVENING AND OVERNIGHT. BUT SNOW AMOUNTS WILL BE LIGHT. WITH THE GFS
NOT SHOWING ANY MEASURABLE PRECIP FOR OUR FORECAST AREA...STILL DID
NOT GO CATEGORICAL POPS EVEN EAST OF I 29...BUT KEPT POPS IN THE
LIKELY CATEGORY FOR THOSE ZONES.
BEHIND THE WARM FRONT..FRIDAY WILL BE MILD. BLENDED THE MOS
CONSENSUS WITH THE RAW ECMWF AND GEM GLOBAL AS 925MB TEMPERATURES
CERTAINLY SUPPORT READINGS WELL INTO THE 30S AND 40S.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 330 PM CST THU FEB 19 2015
COLDER AIR WILL BEGIN FILTERING IN FRIDAY NIGHT BEHIND A BROAD AND
DIFFUSE FRONT. LOW LEVEL MOISTURE SHOULD BE FAIRLY COPIOUS WITH AND
BEHIND THE FRONT AND EXPECT A FEW FLURRIES OVER THE AREA. WILL ALSO
KEEP THAT SLIGHT CHANCE OF MEASURABLE SNOW OVER THE SOUTHWEST CORNER
FOR SATURDAY MORNING. MEANWHILE STRONG CANADIAN HIGH PRESSURE WILL
BE APPROACHING SATURDAY WITH SUBSIDENCE AND RESULTING DRYING
CLEARING OUT SKIES AND ANY FLURRIES FROM THE NORTH/NORTHEAST.
TEMPERATURES WHICH WILL COOL STEADILY BUT MODESTLY INTO THE TEENS
AND 20S FRIDAY NIGHT WILL NOT BE ABLE TO RISE MUCH SATURDAY DESPITE
THE CLEARING SKIES.
THE COLD AIR WILL CONTINUE TO FLOW IN SATURDAY NIGHT INTO SUNDAY
UNDER GENERALLY CLEAR SKIES. ANOTHER GENUINE WIND CHILL ADVISORY
EVENT SEEMS LIKELY BY SUNDAY MORNING...AT LEAST IN OUR NORTH AND
EAST. ACTUAL TEMPERATURES WILL DROP INTO THE SINGLE DIGITS BY SUNDAY
MORNING...BELOW ZERO NORTHEAST TO ABOVE ZERO SOUTHWEST. SUNDAY HIGHS
WILL WARM UNDER THE STRONG LATE FEBRUARY SUNSHINE TO THE SINGLE
DIGITS ABOVE ZERO NORTHEAST TO THE TEENS SOUTHWEST.
THE COLD HIGH WILL MOVE OVER THE AREA SUNDAY NIGHT BRINGING OF
COURSE COLD TEMPERATURES WITH LIGHT WINDS. MONDAY WILL BE A WARMING
DAY WITH AN UNFAVORABLE PATTERN AND DRY AIR COMBINING FOR NO REAL
LIGHT SNOW CHANCE. ANOTHER COLD SHOT SHOULD BEGIN TO ARRIVE TUESDAY
THOUGH THE DAY SHOULD STILL BE FAIRLY MILD...AND WILL GO WITH SOME
SMALL MENTION OF LIGHT SNOW AS PER EXTENDED GUIDANCE.
WEDNESDAY AND THURSDAY WILL SEE A PROCESSION OF UPPER WAVES WHICH
WILL STRENGTHEN/REINFORCE THE NEWEST COLD AIR PUSH...WHILE POSSIBLY
BRINGING A FEW AREAS OF LIGHT SNOW OR FLURRIES...BUT NOTHING VERY
BIG. THE MAIN QUESTION IS THE STRENGTH OF THIS PUSH WHICH HAS BEEN
CHANGING SOMEWHAT IN MODEL SOLUTIONS FROM RUN TO RUN. THE EXTENDED
GUIDANCE TAKES HIGH TEMPERATURE BACK DOWN TO TEENS AND 20S FOR
WEDNESDAY AND THURSDAY. THE 12Z GFS AND EC SUGGEST A STRONGER COLD
INVASION. WILL GO WITH THE GUIDANCE FOR NOW AND CHECK TO SEE IF THIS
SOLUTION REMAINS FOR THE NEXT COUPLE RUNS. ALSO...IF WE DONT GET
BETTER SNOW COVER IN THE NEXT FEW DAYS...SOME OF THE THE BITE WILL
REMAIN OFF THE OUTBREAK. HOWEVER...IT IS LOOKING LIKE GETTING MORE
THAN A DAY OF ABOVE OR EVEN NEAR NORMAL TEMPERATURES IS OUT OF THE
QUESTION AT LEAST UNTIL MARCH BEGINS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 542 PM CST THU FEB 19 2015
MAINLY EXPECTING VFR CONDITIONS THROUGH THE NIGHT AT TAF SITES.
LIGHT SNOW AND FLURRIES HAVING A TOUGH TIME REACHING THE
GROUND...BUT STILL MAY GET A BRIEF PERIOD OF MVFR VIS ALONG AND
EAST OF INTERSTATE 29 IN LIGHT SNOW THIS EVENING. OTHERWISE SIGNS
THAT LOWER MVFR STRATUS CURRENTLY OVER CANADA WILL TRY TO WORK
SOUTH BEHIND THE COLD FRONT AFTER 12Z FRIDAY. STILL QUITE A BIT OF
UNCERTAINTY ON HEIGHT AND COVERAGE OF THIS STRATUS...SO LEFT TAFS
VFR. BUT WILL NEED TO MONITOR TRENDS IN THE OBSERVATIONS AND
FUTURE RUNS OF THE GFS AND RAP MODELS...WITH THE NAM CONTINUING TO
NOT BE OF MUCH USE.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
UPDATE...CHENARD
SHORT TERM...MJ
LONG TERM...
AVIATION...CHENARD
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
547 PM CST THU FEB 19 2015
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 330 PM CST THU FEB 19 2015
WARM FRONT IS PRESSING EASTWARD AT THIS TIME. IN FACT CHAMBERLAIN IS
UP CLOSE TO 30 DEGREES WITH WINNER AT 34 MID THURSDAY AFTERNOON. IN
THE NEAR TERM AND FOR TONIGHT...BELIEVE THAT MANY GUIDANCE VALUES
ARE TOO COLD...IN SOME CASES WAY TOO COLD. NOT SURE WHY TEMPERATURES
WOULD PLUMMET ALL THAT MUCH WITH THIS KIND OF SOUTHERLY FLOW AND THE
WARM FRONT NOT STALLING. THEREFORE TRENDED TOWARD THE WARMER
READINGS WHICH WERE RAW ECMWF VALUES BLENDED WITH MOS CONSENSUS. NOW
ONTO THE WARM FRONTAL SNOW...WHICH HAS SO FAR BEEN TOTALLY NON
EXISTENT IN OUR WESTERN ZONES. BONE DRY AIR IN THE LOW LEVELS...
WITNESSED BY CURRENT SURFACE DEW POINT READINGS STILL HOVER NEAR
ZERO AND SINGLE DIGITS BELOW ZERO ALONG AND EAST OF THE JAMES RIVER
VALLEY...HAS NOT ALLOWED ANYTHING TO REACH THE GROUND. SOME LOW
LEVEL MOISTURE RETURN MAY INCREASE GENERALLY EAST OF I 29 THIS
EVENING AND OVERNIGHT. BUT SNOW AMOUNTS WILL BE LIGHT. WITH THE GFS
NOT SHOWING ANY MEASURABLE PRECIP FOR OUR FORECAST AREA...STILL DID
NOT GO CATEGORICAL POPS EVEN EAST OF I 29...BUT KEPT POPS IN THE
LIKELY CATEGORY FOR THOSE ZONES.
BEHIND THE WARM FRONT..FRIDAY WILL BE MILD. BLENDED THE MOS
CONSENSUS WITH THE RAW ECMWF AND GEM GLOBAL AS 925MB TEMPERATURES
CERTAINLY SUPPORT READINGS WELL INTO THE 30S AND 40S.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 330 PM CST THU FEB 19 2015
COLDER AIR WILL BEGIN FILTERING IN FRIDAY NIGHT BEHIND A BROAD AND
DIFFUSE FRONT. LOW LEVEL MOISTURE SHOULD BE FAIRLY COPIOUS WITH AND
BEHIND THE FRONT AND EXPECT A FEW FLURRIES OVER THE AREA. WILL ALSO
KEEP THAT SLIGHT CHANCE OF MEASURABLE SNOW OVER THE SOUTHWEST CORNER
FOR SATURDAY MORNING. MEANWHILE STRONG CANADIAN HIGH PRESSURE WILL
BE APPROACHING SATURDAY WITH SUBSIDENCE AND RESULTING DRYING
CLEARING OUT SKIES AND ANY FLURRIES FROM THE NORTH/NORTHEAST.
TEMPERATURES WHICH WILL COOL STEADILY BUT MODESTLY INTO THE TEENS
AND 20S FRIDAY NIGHT WILL NOT BE ABLE TO RISE MUCH SATURDAY DESPITE
THE CLEARING SKIES.
THE COLD AIR WILL CONTINUE TO FLOW IN SATURDAY NIGHT INTO SUNDAY
UNDER GENERALLY CLEAR SKIES. ANOTHER GENUINE WIND CHILL ADVISORY
EVENT SEEMS LIKELY BY SUNDAY MORNING...AT LEAST IN OUR NORTH AND
EAST. ACTUAL TEMPERATURES WILL DROP INTO THE SINGLE DIGITS BY SUNDAY
MORNING...BELOW ZERO NORTHEAST TO ABOVE ZERO SOUTHWEST. SUNDAY HIGHS
WILL WARM UNDER THE STRONG LATE FEBRUARY SUNSHINE TO THE SINGLE
DIGITS ABOVE ZERO NORTHEAST TO THE TEENS SOUTHWEST.
THE COLD HIGH WILL MOVE OVER THE AREA SUNDAY NIGHT BRINGING OF
COURSE COLD TEMPERATURES WITH LIGHT WINDS. MONDAY WILL BE A WARMING
DAY WITH AN UNFAVORABLE PATTERN AND DRY AIR COMBINING FOR NO REAL
LIGHT SNOW CHANCE. ANOTHER COLD SHOT SHOULD BEGIN TO ARRIVE TUESDAY
THOUGH THE DAY SHOULD STILL BE FAIRLY MILD...AND WILL GO WITH SOME
SMALL MENTION OF LIGHT SNOW AS PER EXTENDED GUIDANCE.
WEDNESDAY AND THURSDAY WILL SEE A PROCESSION OF UPPER WAVES WHICH
WILL STRENGTHEN/REINFORCE THE NEWEST COLD AIR PUSH...WHILE POSSIBLY
BRINGING A FEW AREAS OF LIGHT SNOW OR FLURRIES...BUT NOTHING VERY
BIG. THE MAIN QUESTION IS THE STRENGTH OF THIS PUSH WHICH HAS BEEN
CHANGING SOMEWHAT IN MODEL SOLUTIONS FROM RUN TO RUN. THE EXTENDED
GUIDANCE TAKES HIGH TEMPERATURE BACK DOWN TO TEENS AND 20S FOR
WEDNESDAY AND THURSDAY. THE 12Z GFS AND EC SUGGEST A STRONGER COLD
INVASION. WILL GO WITH THE GUIDANCE FOR NOW AND CHECK TO SEE IF THIS
SOLUTION REMAINS FOR THE NEXT COUPLE RUNS. ALSO...IF WE DONT GET
BETTER SNOW COVER IN THE NEXT FEW DAYS...SOME OF THE THE BITE WILL
REMAIN OFF THE OUTBREAK. HOWEVER...IT IS LOOKING LIKE GETTING MORE
THAN A DAY OF ABOVE OR EVEN NEAR NORMAL TEMPERATURES IS OUT OF THE
QUESTION AT LEAST UNTIL MARCH BEGINS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 542 PM CST THU FEB 19 2015
MAINLY EXPECTING VFR CONDITIONS THROUGH THE NIGHT AT TAF SITES.
LIGHT SNOW AND FLURRIES HAVING A TOUGH TIME REACHING THE
GROUND...BUT STILL MAY GET A BRIEF PERIOD OF MVFR VIS ALONG AND
EAST OF INTERSTATE 29 IN LIGHT SNOW THIS EVENING. OTHERWISE SIGNS
THAT LOWER MVFR STRATUS CURRENTLY OVER CANADA WILL TRY TO WORK
SOUTH BEHIND THE COLD FRONT AFTER 12Z FRIDAY. STILL QUITE A BIT OF
UNCERTAINTY ON HEIGHT AND COVERAGE OF THIS STRATUS...SO LEFT TAFS
VFR. BUT WILL NEED TO MONITOR TRENDS IN THE OBSERVATIONS AND
FUTURE RUNS OF THE GFS AND RAP MODELS...WITH THE NAM CONTINUING TO
NOT BE OF MUCH USE.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
SHORT TERM...MJ
LONG TERM...
AVIATION...CHENARD
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1135 PM CST TUE FEB 17 2015
.UPDATE...FOR 06Z AVIATION.
&&
.AVIATION...06Z TAF DISCUSSION.
MAINLY VFR CONDITIONS AT ISSUANCE BUT CIGS ARE GOING TO START
FALLING OVER THE NEXT FEW HOURS AS A CLIPPER MOVES INTO THE AREA.
SNOWS WILL LIKELY DROP VIS FOR A FEW HOURS HOURS AROUND SUNRISE TO
AT LEAST MVFR. FLURRIES COULD LINGER AT KCSV INTO THE EARLY
AFTERNOON HOURS...BUT SNOWS SHOULD END AT KCKV AND KBNA BY 14-15Z.
BEHIND THE FRONT WINDS WILL PICK UP. BY 12Z GUSTS WILL BEGIN AT
KCKV...AND SPREAD ACROSS THE MID-STATE. NW GUSTS OF 20-25 KTS ARE
LIKELY.
UNGER
&&
.PREV DISCUSSION... /ISSUED 937 PM CST TUE FEB 17 2015/
UPDATE...LATEST HRRR CONTINUES TO BRING A BAND OF REFLECTIVITY
ACROSS MAINLY NORTHERN MIDDLE TENNESSEE AND THE PLATEAU
OVERNIGHT. BEST ESTIMATES FOR TIMING ARE CKV AROUND 08Z, BNA
AROUND 09Z, AND CSV AROUND 11Z. ENHANCES ECHOES WITHIN THE LARGER
BAND SUGGEST THE HRRR IS HONING IN ON SOME CONVECTIVE POTENTIAL,
SO BRIEF PERIODS OF HEAVIER SNOW ARE POSSIBLE, ESPECIALLY NORTH OF
I-40. HAVE ALREADY MADE SOME ADJUSTMENTS TO THE GRIDS BASED ON
EARLIER RUNS OF THE HRRR AND WILL SEND OUT AN UPDATE SHORTLY.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL NOON CST WEDNESDAY FOR TNZ005>011-
023>034-056>066-075-077>080-093>095.
&&
$$
27
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1209 PM EST WED FEB 18 2015
.SYNOPSIS...
ARCTIC COLD FRONT PLOWS THROUGH OUR AREA THIS AFTERNOON. RECORD
AND DANGEROUSLY COLD TEMPERATURES WILL BE FOUND TONIGHT THROUGH
FRIDAY. ANOTHER STORM SYSTEM ARRIVES THIS WEEKEND WITH A WINTER
WEATHER THREAT.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1010 AM EST WEDNESDAY...
STRONG ARCTIC FRONT STILL ON TRACK TO CROSS THE MOUNTAINS EARLY
THIS AFTERNOON AND OUT EAST LATE IN THE DAY. VERY DYNAMIC SETUP
WITH VERY COLD AIR ALOFT ROTATING THROUGH THE 5H TROUGH WITH A
PASSING VORT AXIS ALONG THE BOUNDARY VERY SIMILAR TO A CONVECTIVE
SCENARIO IN THE SPRING. PROVIDED SOME HEATING/MOISTENING OF THE
BOUNDARY LAYER PER SW FLOW JUST AHEAD OF THE BOUNDARY ESPCLY BLUE
RIDGE EAST EXPECT SHALLOW CONVECTION TO DEVELOP OFF THE RIDGES
EARLY THIS AFTERNOON BEFORE SWEEPING EAST IN BROKEN BAND FASHION
LATER ON. LATEST SPC DAY1 OUTLOOK HAS GENERAL THUNDER OVER MUCH OF
THE CENTRAL/EAST SO INCLUDED THUNDER GIVEN SMALL FORECAST CAPE
AND SOME HEAVIER SNOW SQUALLS PER HRRR UNDER SUCH STRONG SURFACE-
7H LAPSES OFF FORECAST SOUNDINGS. THIS COULD TRANSLATE SOME
STRONGER WINDS TO THE GROUND WITHIN ANY OF THE HEAVIER SNOW
SHOWERS WITH A QUICK INCH OR TWO OF SNOW POSSIBLE.
THUS WENT AHEAD AND INCLUDED SOME THUNDER/GUSTY WIND MENTION
WHILE EXTENDING THE WESTERN WINTER WEATHER ADVISORY EAST TO THE
BLUE RIDGE TO COVER MORE IMPACT RELATED SNOWFALL WHICH MAY ONLY
LAST AN HOUR OR TWO RIGHT AHEAD OF THE FRONT. SOME OF THIS
CONVECTION LIKELY TO HEAD EAST INTO THE WARMER BOUNDARY LAYER
WHERE PLAN TO COVER WITH STATEMENTS FOR NOW PENDING LATER
COVERAGE. OTRW BUMPED UP POPS AND ROLLED POSSIBLE WIND ADVISORY
GUSTS INTO THE WINTER WEATHER ADVISORY. RAISED HIGH TEMPS A NOTCH
IN THE FAR WEST GIVEN CURRENT OBS AND OUT EAST WHERE THINK A
BETTER SHOT AT RECOVERY WITH SOME SPOTS PERHAPS NEAR 40 IF THE
FRONT DOES SLOW UP SOME.
PREVIOUS DISCUSSION AS OF 345 AM EST WEDNESDAY...
NOT MUCH OF BREAK FROM OLD MAN WINTER. ARCTIC FRONT UPSTREAM
ACROSS THE OHIO VALLEY WILL SHIFT EAST ACROSS US TODAY. WILL BE
DEALING FIRST WITH SNOW SHOWERS AND BLOWING SNOW. HIGH-RES MODELS
SEEMED TO HAVE A DECENT HANDLE ON UPSTREAM OBS. INSTABILITY
ACTUALLY INCREASES AT TIMES THROUGH THIS AFTERNOON ENOUGH THAT
SNOW SQUALLS WILL OCCUR. CANNOT RULE OUT THUNDER...BUT ITS
MARGINAL. SITUATION LOOKS SOMEWHAT SIMILAR TO WHAT WE HAD LAST
WEEKEND. THIS DEEPENING TROUGH TO PUSH ARCTIC AIR EAST BY THIS
EVENING. SNOW SHOWERS WILL BE MOST PREVALENT OVER THE MOUNTAINS
BUT AS THE AFTERNOON MOVES ON...EXPECT STREAMERS OF SNOW TO REACH
INTO THE PIEDMONT...WITH SOME AXIS OF FRONTOGENESIS OCCURRING THIS
EVENING ACROSS THE PIEDMONT WITH EPV ALSO IN PLACE...WHICH MAY
LEAD TO MORE COVERAGE EAST OF OUR AREA.
AS FAR AS TOTAL SNOWFALL...THROUGH MIDNIGHT TONIGHT WILL LIKELY
SEE 1 TO 3 INCHES IN THE MOUNTAINS...WITH UP TO 6 INCHES IN WRN
GREENBRIER AND HIGHER TERRAIN OF SW VA/NW NC. AS SUCH HAVE
EXTENDED THE WINTER WX ADVISORY TIL MIDNIGHT TONIGHT. AFTER THAT
THE WIND CHILL WARNING PRODUCT WILL INCLUDE ANY ADDITIONAL
ACCUMULATIONS THAT OCCUR INTO THURSDAY.
TEMPERATURES THIS MORNING WILL START TO RISE AHEAD OF THE FRONT
WITH HIGHS IN THE LOWER TO MID 30S SOUTHEAST TO TEENS/20S WEST.
TEMPS SHOULD FALL TO THE TEENS IN THE WEST BY EVENING WITH UPPER
20S EAST. ARCTIC AIR LAGS BEHIND THE ACTUAL FRONT SOME...SO A
DELAY IS EXPECTED IN THE PIEDMONT.
WINDS SHOULD BEGIN TO INCREASE WITH THE SNOW SHOWERS AND FRONT
TODAY. MODELS HAVE NEAR ADVISORY LEVEL GUSTS IN THE NC MTNS...BUT
NOT SEEING AS LOW OF AN INVERSION...SO SHOULD KEEP WINDS UNDER 50
MPH GUSTS.
AT MIDNIGHT...WIND CHILLS SHOULD START TO REACH INTO ADVISORY
LEVELS IN THE MOUNTAINS BUT QUICKLY DROP TO 20 BELOW BY
MORNING...WHILE THE PIEDMONT AND FOOTHILLS DROP TO 0 TO 10 BELOW
ZERO BY THURSDAY MORNING. PER COLLABORATION WITH NEIGHBORING NWS
OFFICES WE DECIDED TO RUN THE WIND CHILL HEADLINES THROUGH FRIDAY
MORNING...AS THURSDAY WILL NOT SEE TOO MUCH OF A WARMUP.
WILL DROP THE WINTER WX ADVISORY FOR BLACK ICE IN NC BY 7AM.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY/...
AS OF 300 AM EST WEDNESDAY...
A CLOSED UPPER LEVEL LOW WILL TRACK ACROSS PENNSYLVANIA THURSDAY.
THIS SYSTEM WILL BRING LIGHT UPSLOPE SNOW SHOWERS TO WESTERN SLOPES
WITH CLOUDS SPREADING EAST INTO THE PIEDMONT. CLOUDS AND LIGHT SNOW
IS THE LEAST OF OUR WORRIES AS AN ARCTIC AIRMASS WILL KEEP THE
REGION COLD WITH SINGLE DIGITS ACROSS THE MOUNTAINS AND MID TO UPPER
TEENS EAST DURING THE DAY THURSDAY. STRONG WINDS WILL ALSO BLOW
ACROSS THE AREA THURSDAY WITH A TIGHT PRESSURE GRADIENT FROM THE LOW
TO THE NORTH AND HIGH PRESSURE ENTERING THE OHIO VALLEY. THE
COMBINATION OF VERY COLD TEMPERATURES AND STRONG WINDS WILL KEEP
WIND CHILL VALUES BELOW ZERO FOR MUCH OF THE DAY. THE PIEDMONT WIND
CHILLS MAY GO ABOVE ZERO THURSDAY AFTERNOON FOR A FEW HOURS ONLY TO
DROP BACK DOWN THURSDAY NIGHT. FOR SIMPLICITY SAKE AND IMPACT FROM
THIS HISTORIC EVENT...WE WILL CONTINUE WITH WIND CHILL WARNINGS
ALONG AND WEST OF THE BLUE RIDGE AND ADVISORIES EAST OF THE BLUE
RIDGE INTO FRIDAY MORNING. IF HIGH PRESSURE BUILDS IN OVER THE AREA
ALLOWING WINDS TO DECOUPLE...WE COULD DOWN GRADE HEADLINES LATER. NO
MATTER HOW YOU LOOK AT IT...WIND OR NO WIND...IT WILL BE A BITTER
COLD PERIOD INTO THURSDAY INTO FRIDAY MORNING.
HIGH PRESSURE TRACKS ACROSS THE REGION FRIDAY. WITH A DRY AIRMASS
AND ABUNDANT SUNSHINE...TEMPERATURES WILL SEEMS MILD WITH HIGHS IN
THE 20S. HIGH PRESSURE SLIDES OFF THE VIRGINIA AND NORTH CAROLINA
COAST FRIDAY NIGHT...ALLOWING A WARM FRONT TO TRACK NORTH ACROSS THE
TENNESSEE-SOUTHERN OHIO VALLEYS. CLOUDS SHOULD HOLD OFF FRIDAY
EVENING AND WITH GOOD RADIATIONAL COOLING...SEND TEMPERATURES DOWN
INTO THE SINGLE DIGITS ACROSS MOUNTAIN VALLEYS AND POINTS EAST OF
THE BLUE RIDGE. WARM AIR WORKING IN ALOFT WILL KEEP RIDGES
TEMPERATURES 10F WARMER THAN EVERYONE ELSE.
ISENTROPIC LIFT AND SHORT WAVES ALONG THE WARM FRONT WILL PUSH
MOISTURE IN ACROSS SOUTHWESTERN VIRGINIA LATE FRIDAY NIGHT...THEN
OVER SPREAD THE REGION DURING THE DAY SATURDAY. PRECIPITATION LIKELY
TO START AS SNOW...THEN TRANSITION TO SLEET BEFORE BECOMING ALL RAIN
BY LATE IN THE AFTERNOON. PRECIPITATION FALLING INTO EXITING RIDGE
WILL CREATE AN INSITU WEDGE. MODELS ARE KEEPING TEMPERATURES IN A
30F-33F RANGE ALONG THE BLUE RIDGE AND NORTH OF HWY 460 INTO
SATURDAY AFTERNOON. THESE AREAS WILL KEEP SNOW LONGER UNLESS WARM
NOSES IS STRONGER AND IN THAT CASE...SLEET INTO THE AFTERNOON. FOR
NOW...KEEPING P-TYPE AS RAIN/SNOW. WARMER AIR OVER TAKE THE FORECAST
AREA SATURDAY NIGHT FOR ALL P-TYPE TO BE RAIN.
&&
.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
AS OF 315 AM EST WEDNESDAY...
INSITU WEDGE WILL ERODE OVERNIGHT AS LOW PRESSURE TRACKS INTO THE
OHIO VALLEY. PRECIPITATION INTENSITY WILL WANE OVERNIGHT AS THE WARM
FRONT TRACKS NORTH AND WE AWAIT THE COLD FRONTAL PASSAGE SUNDAY
AFTERNOON. P-TYPE SHOULD BE ALL LIQUID (RAIN/DRIZZLE) BY LATE
SATURDAY NIGHT INTO SUNDAY. THE FRONT CROSSES THE MOUNTAINS SUNDAY
AFTERNOON...THEN THE PIEDMONT EARLY IN THE EVENING. TEMPERATURES
WILL GET A BOOST AHEAD OF THE COLD FRONT WITH UPPER 40S TO LOWER 50S
FORECASTED FOR SUNDAY. TEMPERATURES DROP BACK INTO THE 20S SUNDAY
NIGHT WITH SCATTERED MOUNTAIN SNOW SHOWERS INTO THE DAY MONDAY.
TEMPERATURES MONDAY AND TUESDAY WILL RUN BELOW NORMAL.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AS OF 1158 AM EST WEDNESDAY...
MVFR TO IFR CONDITIONS IN LOW CIGS AND SNOW SHOWERS TO PERSIST AT
KBLF/KLWB THROUGH THE AFTERNOON. MAIN BAND OF MODERATE SNOW
SHOWERS/SNOW SQUALLS TO ACCOMPANY AN ARCTIC FRONT ACROSS THE BLUE
RIDGE INCLUDING KBCB/KROA BY 18Z/1PM...REACHING...AND KLYH/KDAN
19-21Z. KEPT TEMPO GROUPS FOR POTENTIAL STRONG WIND GUSTS AND
LOWER VSBYS/CIGS AT ALL SITES. EXPECT TO RETURN TO VFR EAST OF THE
MTNS BY EVENING WITH SNOW SHOWERS PERSISTING AT KBLF/KLWB INTO
THE EVENING TAPERING OFF OVERNIGHT...BUT CIGS STAYING MVFR. WINDS
WILL BE INCREASING AND VEERING TO THE WEST WITH THE SNOW SHOWERS
AND BEHIND THE FRONT. GUSTS TO 25 TO 40 KTS NOT OUT OF THE
QUESTION ESPCLY WITHIN THE HEAVIER BAND OF SNOW SHOWERS.
UPSLOPE MVFR TO CONTINUE INTO THURSDAY IN SOUTHEAST WEST VA...WITH
VFR EAST.
WIDESPREAD VFR RETURNS FOR ALL LOCATIONS THURSDAY NIGHT INTO
FRIDAY UNDER DRY/ARCTIC HIGH PRESSURE. CLOUDS WILL INCREASE
FRIDAY NIGHT BUT LIKELY STILL VFR.
ANOTHER COMPLEX STORM SYSTEM WILL AFFECT THE AREA SATURDAY INTO
SUNDAY WITH SUB VFR CONDITIONS AND A MIX OF WINTER WEATHER.
IMPROVING CONDITIONS SHOULD TAKE SHAPE SUNDAY NIGHT WITH A RETURN
TO VFR MOST SITES MONDAY EXCLUDING SOUTHEAST WEST VA WHERE MVFR
CIGS AND FLURRIES MAY PERSIST.
&&
.CLIMATE...
LOW MAXIMUM (COLDEST HIGH) TEMPERATURE RECORDS FOR THURSDAY (FEB 19).
ROA 28/1958
LYH 25/1903
DAN 20/1979
BLF 20/1960
LWB 28/2006
RNK 10/1958
LOW MINIMUM (COLDEST LOWS) TEMPERATURE RECORDS FOR THURSDAY AND FRIDAY.
2/19 2/20
ROA 7/1979 9/1979
LYH 8/1903 7/1896
DAN 11/1973 10/1979
BLF 3/1993 8/1960
LWB 3/2006 6/1979
RNK -2/1958 2/1972
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR
VAZ011>014-016>020-022>024-032.
WIND CHILL WARNING FROM MIDNIGHT TONIGHT TO 10 AM EST FRIDAY
FOR VAZ007-009>020.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR VAZ007-
009-010-015.
WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 10 AM EST FRIDAY
FOR VAZ022>024-032>035-043>047-058-059.
NC...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR NCZ003-
019-020.
WIND CHILL WARNING FROM MIDNIGHT TONIGHT TO 10 AM EST FRIDAY
FOR NCZ001-002-018.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR NCZ001-
002-018.
WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 10 AM EST FRIDAY
FOR NCZ003>006-019-020.
WV...WIND CHILL WARNING FROM MIDNIGHT TONIGHT TO 10 AM EST FRIDAY
FOR WVZ042>044-507-508.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR
WVZ042>044-507-508.
&&
$$
SYNOPSIS...JH/PH
NEAR TERM...JH/WP
SHORT TERM...RCS
LONG TERM...KK
AVIATION...AMS/JH/WP
CLIMATE...PH
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1024 AM EST WED FEB 18 2015
.SYNOPSIS...
ARCTIC COLD FRONT PLOWS THROUGH OUR AREA THIS AFTERNOON. RECORD
AND DANGEROUSLY COLD TEMPERATURES WILL BE FOUND TONIGHT THROUGH
FRIDAY. ANOTHER STORM SYSTEM ARRIVES THIS WEEKEND WITH A WINTER
WEATHER THREAT.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1010 AM EST WEDNESDAY...
STRONG ARCTIC FRONT STILL ON TRACK TO CROSS THE MOUNTAINS EARLY
THIS AFTERNOON AND OUT EAST LATE IN THE DAY. VERY DYNAMIC SETUP
WITH VERY COLD AIR ALOFT ROTATING THROUGH THE 5H TROUGH WITH A
PASSING VORT AXIS ALONG THE BOUNDARY VERY SIMILAR TO A CONVECTIVE
SCENARIO IN THE SPRING. PROVIDED SOME HEATING/MOISTENING OF THE
BOUNDARY LAYER PER SW FLOW JUST AHEAD OF THE BOUNDARY ESPCLY BLUE
RIDGE EAST EXPECT SHALLOW CONVECTION TO DEVELOP OFF THE RIDGES
EARLY THIS AFTERNOON BEFORE SWEEPING EAST IN BROKEN BAND FASHION
LATER ON. LATEST SPC DAY1 OUTLOOK HAS GENERAL THUNDER OVER MUCH OF
THE CENTRAL/EAST SO INCLUDED THUNDER GIVEN SMALL FORECAST CAPE
AND SOME HEAVIER SNOW SQUALLS PER HRRR UNDER SUCH STRONG SURFACE-
7H LAPSES OFF FORECAST SOUNDINGS. THIS COULD TRANSLATE SOME
STRONGER WINDS TO THE GROUND WITHIN ANY OF THE HEAVIER SNOW
SHOWERS WITH A QUICK INCH OR TWO OF SNOW POSSIBLE.
THUS WENT AHEAD AND INCLUDED SOME THUNDER/GUSTY WIND MENTION
WHILE EXTENDING THE WESTERN WINTER WEATHER ADVISORY EAST TO THE
BLUE RIDGE TO COVER MORE IMPACT RELATED SNOWFALL WHICH MAY ONLY
LAST AN HOUR OR TWO RIGHT AHEAD OF THE FRONT. SOME OF THIS
CONVECTION LIKELY TO HEAD EAST INTO THE WARMER BOUNDARY LAYER
WHERE PLAN TO COVER WITH STATEMENTS FOR NOW PENDING LATER
COVERAGE. OTRW BUMPED UP POPS AND ROLLED POSSIBLE WIND ADVISORY
GUSTS INTO THE WINTER WEATHER ADVISORY. RAISED HIGH TEMPS A NOTCH
IN THE FAR WEST GIVEN CURRENT OBS AND OUT EAST WHERE THINK A
BETTER SHOT AT RECOVERY WITH SOME SPOTS PERHAPS NEAR 40 IF THE
FRONT DOES SLOW UP SOME.
PREVIOUS DISCUSSION AS OF 345 AM EST WEDNESDAY...
NOT MUCH OF BREAK FROM OLD MAN WINTER. ARCTIC FRONT UPSTREAM
ACROSS THE OHIO VALLEY WILL SHIFT EAST ACROSS US TODAY. WILL BE
DEALING FIRST WITH SNOW SHOWERS AND BLOWING SNOW. HIGH-RES MODELS
SEEMED TO HAVE A DECENT HANDLE ON UPSTREAM OBS. INSTABILITY
ACTUALLY INCREASES AT TIMES THROUGH THIS AFTERNOON ENOUGH THAT
SNOW SQUALLS WILL OCCUR. CANNOT RULE OUT THUNDER...BUT ITS
MARGINAL. SITUATION LOOKS SOMEWHAT SIMILAR TO WHAT WE HAD LAST
WEEKEND. THIS DEEPENING TROUGH TO PUSH ARCTIC AIR EAST BY THIS
EVENING. SNOW SHOWERS WILL BE MOST PREVALENT OVER THE MOUNTAINS
BUT AS THE AFTERNOON MOVES ON...EXPECT STREAMERS OF SNOW TO REACH
INTO THE PIEDMONT...WITH SOME AXIS OF FRONTOGENESIS OCCURRING THIS
EVENING ACROSS THE PIEDMONT WITH EPV ALSO IN PLACE...WHICH MAY
LEAD TO MORE COVERAGE EAST OF OUR AREA.
AS FAR AS TOTAL SNOWFALL...THROUGH MIDNIGHT TONIGHT WILL LIKELY
SEE 1 TO 3 INCHES IN THE MOUNTAINS...WITH UP TO 6 INCHES IN WRN
GREENBRIER AND HIGHER TERRAIN OF SW VA/NW NC. AS SUCH HAVE
EXTENDED THE WINTER WX ADVISORY TIL MIDNIGHT TONIGHT. AFTER THAT
THE WIND CHILL WARNING PRODUCT WILL INCLUDE ANY ADDITIONAL
ACCUMULATIONS THAT OCCUR INTO THURSDAY.
TEMPERATURES THIS MORNING WILL START TO RISE AHEAD OF THE FRONT
WITH HIGHS IN THE LOWER TO MID 30S SOUTHEAST TO TEENS/20S WEST.
TEMPS SHOULD FALL TO THE TEENS IN THE WEST BY EVENING WITH UPPER
20S EAST. ARCTIC AIR LAGS BEHIND THE ACTUAL FRONT SOME...SO A
DELAY IS EXPECTED IN THE PIEDMONT.
WINDS SHOULD BEGIN TO INCREASE WITH THE SNOW SHOWERS AND FRONT
TODAY. MODELS HAVE NEAR ADVISORY LEVEL GUSTS IN THE NC MTNS...BUT
NOT SEEING AS LOW OF AN INVERSION...SO SHOULD KEEP WINDS UNDER 50
MPH GUSTS.
AT MIDNIGHT...WIND CHILLS SHOULD START TO REACH INTO ADVISORY
LEVELS IN THE MOUNTAINS BUT QUICKLY DROP TO 20 BELOW BY
MORNING...WHILE THE PIEDMONT AND FOOTHILLS DROP TO 0 TO 10 BELOW
ZERO BY THURSDAY MORNING. PER COLLABORATION WITH NEIGHBORING NWS
OFFICES WE DECIDED TO RUN THE WIND CHILL HEADLINES THROUGH FRIDAY
MORNING...AS THURSDAY WILL NOT SEE TOO MUCH OF A WARMUP.
WILL DROP THE WINTER WX ADVISORY FOR BLACK ICE IN NC BY 7AM.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY/...
AS OF 300 AM EST WEDNESDAY...
A CLOSED UPPER LEVEL LOW WILL TRACK ACROSS PENNSYLVANIA THURSDAY.
THIS SYSTEM WILL BRING LIGHT UPSLOPE SNOW SHOWERS TO WESTERN SLOPES
WITH CLOUDS SPREADING EAST INTO THE PIEDMONT. CLOUDS AND LIGHT SNOW
IS THE LEAST OF OUR WORRIES AS AN ARCTIC AIRMASS WILL KEEP THE
REGION COLD WITH SINGLE DIGITS ACROSS THE MOUNTAINS AND MID TO UPPER
TEENS EAST DURING THE DAY THURSDAY. STRONG WINDS WILL ALSO BLOW
ACROSS THE AREA THURSDAY WITH A TIGHT PRESSURE GRADIENT FROM THE LOW
TO THE NORTH AND HIGH PRESSURE ENTERING THE OHIO VALLEY. THE
COMBINATION OF VERY COLD TEMPERATURES AND STRONG WINDS WILL KEEP
WIND CHILL VALUES BELOW ZERO FOR MUCH OF THE DAY. THE PIEDMONT WIND
CHILLS MAY GO ABOVE ZERO THURSDAY AFTERNOON FOR A FEW HOURS ONLY TO
DROP BACK DOWN THURSDAY NIGHT. FOR SIMPLICITY SAKE AND IMPACT FROM
THIS HISTORIC EVENT...WE WILL CONTINUE WITH WIND CHILL WARNINGS
ALONG AND WEST OF THE BLUE RIDGE AND ADVISORIES EAST OF THE BLUE
RIDGE INTO FRIDAY MORNING. IF HIGH PRESSURE BUILDS IN OVER THE AREA
ALLOWING WINDS TO DECOUPLE...WE COULD DOWN GRADE HEADLINES LATER. NO
MATTER HOW YOU LOOK AT IT...WIND OR NO WIND...IT WILL BE A BITTER
COLD PERIOD INTO THURSDAY INTO FRIDAY MORNING.
HIGH PRESSURE TRACKS ACROSS THE REGION FRIDAY. WITH A DRY AIRMASS
AND ABUNDANT SUNSHINE...TEMPERATURES WILL SEEMS MILD WITH HIGHS IN
THE 20S. HIGH PRESSURE SLIDES OFF THE VIRGINIA AND NORTH CAROLINA
COAST FRIDAY NIGHT...ALLOWING A WARM FRONT TO TRACK NORTH ACROSS THE
TENNESSEE-SOUTHERN OHIO VALLEYS. CLOUDS SHOULD HOLD OFF FRIDAY
EVENING AND WITH GOOD RADIATIONAL COOLING...SEND TEMPERATURES DOWN
INTO THE SINGLE DIGITS ACROSS MOUNTAIN VALLEYS AND POINTS EAST OF
THE BLUE RIDGE. WARM AIR WORKING IN ALOFT WILL KEEP RIDGES
TEMPERATURES 10F WARMER THAN EVERYONE ELSE.
ISENTROPIC LIFT AND SHORT WAVES ALONG THE WARM FRONT WILL PUSH
MOISTURE IN ACROSS SOUTHWESTERN VIRGINIA LATE FRIDAY NIGHT...THEN
OVER SPREAD THE REGION DURING THE DAY SATURDAY. PRECIPITATION LIKELY
TO START AS SNOW...THEN TRANSITION TO SLEET BEFORE BECOMING ALL RAIN
BY LATE IN THE AFTERNOON. PRECIPITATION FALLING INTO EXITING RIDGE
WILL CREATE AN INSITU WEDGE. MODELS ARE KEEPING TEMPERATURES IN A
30F-33F RANGE ALONG THE BLUE RIDGE AND NORTH OF HWY 460 INTO
SATURDAY AFTERNOON. THESE AREAS WILL KEEP SNOW LONGER UNLESS WARM
NOSES IS STRONGER AND IN THAT CASE...SLEET INTO THE AFTERNOON. FOR
NOW...KEEPING P-TYPE AS RAIN/SNOW. WARMER AIR OVER TAKE THE FORECAST
AREA SATURDAY NIGHT FOR ALL P-TYPE TO BE RAIN.
&&
.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
AS OF 315 AM EST WEDNESDAY...
INSITU WEDGE WILL ERODE OVERNIGHT AS LOW PRESSURE TRACKS INTO THE
OHIO VALLEY. PRECIPITATION INTENSITY WILL WANE OVERNIGHT AS THE WARM
FRONT TRACKS NORTH AND WE AWAIT THE COLD FRONTAL PASSAGE SUNDAY
AFTERNOON. P-TYPE SHOULD BE ALL LIQUID (RAIN/DRIZZLE) BY LATE
SATURDAY NIGHT INTO SUNDAY. THE FRONT CROSSES THE MOUNTAINS SUNDAY
AFTERNOON...THEN THE PIEDMONT EARLY IN THE EVENING. TEMPERATURES
WILL GET A BOOST AHEAD OF THE COLD FRONT WITH UPPER 40S TO LOWER 50S
FORECASTED FOR SUNDAY. TEMPERATURES DROP BACK INTO THE 20S SUNDAY
NIGHT WITH SCATTERED MOUNTAIN SNOW SHOWERS INTO THE DAY MONDAY.
TEMPERATURES MONDAY AND TUESDAY WILL RUN BELOW NORMAL.
&&
.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
AS OF 645 AM EST WEDNESDAY...
EXPECTING A BAND OF MODERATE SNOW SHOWERS/SNOW SQUALLS TO
ACCOMPANY AN ARCTIC FRONT TODAY...REACHING BLF/LWB IN THE 15-17Z
TIME FRAME...BCB/ROA 17-19Z...AND LYH/DAN 19-21Z. HAVE TEMPO
GROUPS FOR POTENTIAL STRONG WIND GUSTS AND LOWER VSBYS/CIGS AT ALL
SITES. EXPECT TO RETURN TO VFR EAST OF THE MTNS BY EVENING WITH
SNOW SHOWERS PERSISTING AT BLF/LWB INTO THE EVENING TAPERING OFF
OVERNIGHT...BUT CIGS STAYING MVFR. WINDS WILL BE SOUTHWEST AND
LIGHT THIS MORNING INCREASING AND VEERING TO THE WEST WITH THE
SNOW SHOWERS AND BEHIND THE FRONT. GUSTS TO 25 TO 35 KTS NOT OUT
OF THE QUESTION.
UPSLOPE MVFR TO CONTINUE INTO THURSDAY IN SE WV...WITH VFR EAST.
WIDESPREAD VFR RETURNS FOR ALL LOCATIONS THURSDAY NIGHT INTO
FRIDAY UNDER DRY/ARCTIC HIGH PRESSURE. CLOUDS WILL INCREASE
FRIDAY NIGHT BUT LIKELY STILL VFR.
ANOTHER COMPLEX STORM SYSTEM WILL AFFECT THE AREA SATURDAY INTO
SUNDAY WITH SUB VFR CONDITIONS AND A MIX OF WINTER WEATHER.
&&
.CLIMATE...
LOW MAXIMUM (COLDEST HIGH) TEMPERATURE RECORDS FOR THURSDAY (FEB 19).
ROA 28/1958
LYH 25/1903
DAN 20/1979
BLF 20/1960
LWB 28/2006
RNK 10/1958
LOW MINIMUM (COLDEST LOWS) TEMPERATURE RECORDS FOR THURSDAY AND FRIDAY.
2/19 2/20
ROA 7/1979 9/1979
LYH 8/1903 7/1896
DAN 11/1973 10/1979
BLF 3/1993 8/1960
LWB 3/2006 6/1979
RNK -2/1958 2/1972
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR
VAZ011>014-016>020-022>024-032.
WIND CHILL WARNING FROM MIDNIGHT TONIGHT TO 10 AM EST FRIDAY
FOR VAZ007-009>020.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR VAZ007-
009-010-015.
WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 10 AM EST FRIDAY
FOR VAZ022>024-032>035-043>047-058-059.
NC...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR NCZ003-
019-020.
WIND CHILL WARNING FROM MIDNIGHT TONIGHT TO 10 AM EST FRIDAY
FOR NCZ001-002-018.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR NCZ001-
002-018.
WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 10 AM EST FRIDAY
FOR NCZ003>006-019-020.
WV...WIND CHILL WARNING FROM MIDNIGHT TONIGHT TO 10 AM EST FRIDAY
FOR WVZ042>044-507-508.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR
WVZ042>044-507-508.
&&
$$
SYNOPSIS...JH/PH
NEAR TERM...JH/WP
SHORT TERM...RCS
LONG TERM...KK
AVIATION...AMS/JH/WP
CLIMATE...PH
AREA FORECAST DISCUSSION
NWS SAN JOAQUIN VALLEY - HANFORD CA
1020 PM PST THU FEB 19 2015
.SYNOPSIS...
PATCHY FOG WILL ONCE AGAIN BE POSSIBLE TONIGHT INTO EARLY FRIDAY
MORNING. OTHERWISE...A STORM SYSTEM WILL APPROACH THE REGION DURING
THE SECOND HALF OF THE WEEKEND BRINGING COOLER TEMPERATURES AND A
POSSIBILITY OF RAIN TO MUCH OF THE REGION. DRY WEATHER WILL RETURN TO
THE AREA TUESDAY AND CONTINUE THROUGH THE REST OF THE WORK WEEK.
&&
.DISCUSSION...FORECAST UPDATED TO INCLUDE DENSE FOG FOR MUCH OF
THE VALLEY THROUGH 10 AM FRIDAY. DENSE FOG ADVISORY HAS BEEN
ISSUED WITH VISIBILITY EXPECTED TO FALL TO 200 FEET OR LESS IN
PLACES...SIMILAR TO CONDITIONS OBSERVED EARLY THIS MORNING. FRESNO
WAS ADDED TO THE DENSE FOG ADVISORY...HOWEVER CONFIDENCE IS LOW
GIVEN THEY DID NOT EXPERIENCE DENSE FOG CONDITIONS THIS MORNING.
THE HRRR HAS BEEN PERSISTENT WITH FRESNO FALLING TO A QUARTER MILE
OR LESS BY 2 AM.
&&
.PREV DISCUSSION... /ISSUED 913 PM PST THU FEB 19 2015/
DISCUSSION...THE FORECAST HAS BEEN UPDATED TO INCLUDE THE
POSSIBILITY OF RAIN FOR THE VALLEY AND FOOTHILL LOCATIONS
BEGINNING LATE SUNDAY MORNING AND CONTINUING INTO EARLY MONDAY
MORNING. THE TREND OF THE OPERATIONAL MODELS AND ENSEMBLE MEAN ARE
TRENDING THE UPPER LOW WESTERLY OVER THE WEEKEND...ALLOWING MUCH
OF THE REGION TO BE IMPACTED WITH RAIN. ADDITIONALLY...THE MOD
TREND HAS BEEN TRENDING DEEPER WITH THE UPPER LOW...ADDING A
LITTLE MORE CONFIDENCE TO THIS FORECAST. LASTLY...THE NAEFS
PROBABILITY OF MEASUREABLE PRECIPITATION HAS ALSO BEEN TRENDING
HIGHER FROM MODEL RUN TO MODEL RUN. WE WILL CONTINUE TO MONITOR
THE FORECAST CLOSELY AND FINE TUNE ESPECIALLY IN THE NEXT 36 HOURS
WHEN WE BEGIN TO SEE THE HIGH RES ARW AND NMM DATA.
&&
.AVIATION...
IN THE SAN JOAQUIN VALLEY...AREAS OF IFR WITH LOCAL LIFR/VLIFR
IN FOG CAN BE EXPECTED BETWEEN 08Z AND 18Z FRIDAY. OTHERWISE... MVFR
CONDITIONS WILL PREVAIL IN HAZE DURING THE NEXT 24 HOURS. ELSEWHERE
ACROSS THE CENTRAL CALIFORNIA INTERIOR...VFR CONDITIONS CAN BE
EXPECTED DURING THE NEXT 24 HOURS.
&&
.AIR QUALITY ISSUES...
ON FRIDAY FEBRUARY 20 2015... UNHEALTHY FOR SENSITIVE GROUPS IN
KERN COUNTY. FIREPLACE/WOOD STOVE BURNING STATUS IS: NO BURNING
UNLESS REGISTERED IN FRESNO... KERN... KINGS... MADERA... MERCED
AND TULARE COUNTIES.
FURTHER INFORMATION IS AVAILABLE AT VALLEYAIR.ORG
&&
.CERTAINTY...
THE LEVEL OF CERTAINTY FOR DAYS 1 AND 2 IS MEDIUM.
THE LEVEL OF CERTAINTY FOR DAYS 3 THROUGH 7 IS MEDIUM.
THIS INFORMATION IS PROVIDED AS PART OF A TRIAL PROJECT CONDUCTED
BY THE NATIONAL WEATHER SERVICE SAN JOAQUIN VALLEY - HANFORD.
CERTAINTY LEVELS INCLUDE LOW...MEDIUM...AND HIGH. PLEASE VISIT
WWW.WEATHER.GOV/HNX/CERTAINTY.PHP /ALL LOWER CASE/ FOR ADDITIONAL
INFORMATION AND/OR TO PROVIDE FEEDBACK.
&&
.CLIMATE...
RECORDS
SITE DATE HI_MAX:YEAR LO_MAX:YEAR HI_MIN:YEAR LO_MIN:YEAR
KFAT 02-19 79:1977 47:1897 55:1996 28:1953
KFAT 02-20 80:1896 45:1909 56:1968 28:1953
KFAT 02-21 77:1991 46:1959 56:1901 26:1953
KBFL 02-19 85:1977 52:1969 54:1996 28:1953
KBFL 02-20 81:1977 52:1922 57:1968 26:1906
KBFL 02-21 82:1991 54:1975 54:2005 27:1893
&&
.HNX WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 10 AM PST FRIDAY CAZ089>092.
&&
$$
PUBLIC...RILEY
AVN/FW...BEAN
PREV DISCUSSION...RILEY
SYNOPSIS...RILEY
WEATHER.GOV/HANFORD
AREA FORECAST DISCUSSION
NWS PADUCAH KY
1018 PM CST THU FEB 19 2015
.UPDATE...
ISSUED AT 1018 PM CST THU FEB 19 2015
HAD TO MAKE A LAST MINUTE COLLABORATION CHANGE FOR POPS/WEATHER
FOR THE REST OF TONIGHT. MAIN FOCUS WAS TO REDUCE SNOW CHANCES
THROUGH MOST OF THE NIGHT, INCREASING POPS FROM THE
SOUTH/SOUTHWEST AROUND DAYBREAK. OTHERWISE, NO CHANGES WERE MADE
FROM EARLIER TEMPERATURE, WIND, AND DEWPOINT CHANGES.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 247 PM CST THU FEB 19 2015
...TONIGHT THROUGH FRIDAY...
RADAR/OBS NETWORK SHOWS SOME 20DBZ PLUS ECHOES IN WESTERN MO
PRODUCING LIGHT SNOW AT TIMES. THE RUN TO RUN MODEL TRENDS HAVE BEEN
CONSISTENTLY BRINGING THIS PCPN INTO SEMO OVERNIGHT...IMPACTING SEMO
AND NEARBY SWIL/FAR SWKY. WITH THE LOWER 3K FEET REMAINING QUITE
DRY...THE END RESULT IS AN ADJUSTED SNOW ACCUMULATION FORECAST GRID
TOTAL TONITE OF NOT MORE THAN ABOUT A HALF INCH OR SO FOR THAT
AREA...BASED ON LIQUID QPF OF 2-3 HUNDREDTHS OF AN INCH.
ON TO FRIDAY...WARMING ALOFT IS NOTED...AND THE SOUNDINGS LIKEWISE
SHOW DRYING IN THE -10C TO -20C LAYER AS THIS OCCURS. THE WARM NOSE
GROWS ABOUT 4K FEET THICK IN THE APPROX 3K-7K FEET ALOFT LAYER (AT
ITS PEAK)...AND THE END RESULT IS A TRANSITION FROM SNOW TO SLEET
FOR ALL AS THE DAY WEARS ON. LIQUID QPF YIELDS COMBO SNOW/ICE TOTALS
IN MAINLY THE SOUTH/WEST HALF OF ABOUT 1/2 INCH TO 3/4 INCH SWATH
AVERAGE AMOUNTS ACROSS FAR SEMO/SOUTHERN-MOST SOUTHWEST KY DURING
THIS TIME FRAME. FURTHER NORTH/EAST...IT APPEARS TO BE STILL TOO
COLD/KEPT ALL SNOW MENTION...THOUGH WE ACKNOWLEDGE THIS STARTS TO
CHANGE CLOSE TO 00Z SATURDAY (AROUND 22-23Z FRIDAY) AS YOU MOVE
EAST OF THE LAKES.
...FRIDAY NIGHT THROUGH SUNDAY...
THE 12Z GFS AND ECMWF ARE IN VERY GOOD AGREEMENT IN THE
LOCATION/PATH OF THE SURFACE LOW/TROUGH FRIDAY NIGHT THROUGH
SATURDAY. THIS FORECAST CLOSELY FOLLOWS A BLEND OF THESE TWO
MODELS.
THERE ARE A FEW NOTABLE CHANGES FROM YESTERDAY. THE ELEVATED
INSTABILITY IN THE GFS IS SOUTH OF THE REGION...BUT THE ECMWF
STILL HAS SOME IN THE SOUTHERN THIRD OF THE AREA LATE FRIDAY NIGHT
AND SATURDAY. SPC`S DAY 2 STILL HAS THAT AREA IN GENERAL
THUNDER...SO KEPT A MENTION.
THE GFS IS WETTER THAN THE ECMWF...BUT THE HEAVIEST RAINS ARE
TRENDING SOUTHEAST. WITH THIS TREND IN MIND AND ALL OF THE WINTER
QUESTIONS IN THE MEANTIME...WILL NOT BE ISSUING ANY FLOOD RELATED
PRODUCTS WITH THIS FORECAST PACKAGE. WE WILL CONTINUE TO MENTION
THE CONCERN IN THE HWO.
AS FOR THE WINTER MESS. DECIDED TO GO WITH A WINTER STORM WATCH
FOR THE ENTIRE AREA FROM 18Z FRIDAY TO 12Z SATURDAY. STILL HAVING
A HARD TIME COMING UP WITH SIGNIFICANT SNOW/SLEET OR ICE
ACCUMULATIONS...BUT WE WILL SEE SOME OF ALL THREE PRECIPITATION
TYPES...AND THE POTENTIAL IS THERE FOR SOME AREAS TO REACH WARNING
CRITERIA FOR THE COMBINATION OF ICE AND SNOW/SLEET.
WE ARE STILL VERY CONCERNED ABOUT THE ICING POTENTIAL FRIDAY
NIGHT...BUT THE ECMWF AND GFS CONTINUE TO BE VERY AGGRESSIVE IN
WARMING TEMPERATURES ABOVE FREEZING OVER THE ENTIRE AREA BY 12Z
SATURDAY. FIGURE THAT ANY ICING ISSUES WILL BE SHORT-LIVED IN THIS
SCENARIO. HOWEVER...WE WILL CONTINUE TO MONITOR FUTURE RUNS FOR A
SHIFT IN THE PATH OF THE SURFACE LOW.
THE 12Z NAM WAS QUITE COLD AND CERTAINLY IS NOT UNBELIEVABLE. IT
IS AN OUTLIER AT THIS TIME...SO WILL CONSIDER IT TO BE THE COLD
END OF THE RANGE OF POSSIBILITIES...BUT WILL STAY WITH THE
MAJORITY OF GUIDANCE WHICH IS MORE IN LINE WITH THE EXISTING
FORECAST.
THE 12Z MODELS ARE IN AGREEMENT IN PUSHING THE PRECIPITATION
MOSTLY EAST OF THE AREA BY 06Z SUNDAY...SO THERE IS NOT MUCH TIME
FOR A CHANGE OVER TO SNOW OR FREEZING RAIN BEFORE THE
PRECIPITATION COMES TO AN END. WILL MENTION THE CHANGE OVER...BUT
WITH LITTLE OR NO ICE/SNOW ACCUMULATION.
AS FOR TEMPERATURES...TRENDED DOWNWARD A BIT FOR SATURDAY...BUT
STILL ABOVE FREEZING. ALSO TRENDED DOWNWARD FOR SATURDAY NIGHT AND
SUNDAY...AS ANOTHER MAJOR SURFACE HIGH SETTLES OVER THE REGION.
.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 247 PM CST THU FEB 19 2015
THIS TIME FRAME IS LARGELY DESCRIBED AS A DRY/COLD PORTION OF THE
FORECAST. WE`LL BE ON THE BACKSIDE OF THE DEPARTING SYSTEM SUNDAY
WITH ITS REINFORCED ARCTIC AIR FUNNELING IN...CREATING SUNDAY HIGHS
IN THE 20S NORTH...TAPERING TO LOWER 30S SOUTH/EAST. THE ARCTIC AIR
COMES IN FULL FORCE ON AS A 1040-45MB SURFACE HIGH BUILDS ACROSS THE
OHIO VALLEY. RESULTANT LOWS WILL FALL INTO THE SINGLE DIGITS/EVEN
NEAR ZERO NORTH...AND LOWER TEENS SOUTH...SUNDAY NIGHT.
CORRESPONDING NEXT DAY LOWS UNDER SAME HIGH PRESSURE SYSTEM RANGE
FROM TEENS NORTH TO 20S SOUTH.
THE HIGH MOVES EAST BY MID WEEK AND WE START TO MODERATE BEFORE THE
NEXT REINFORCING COLD SHOT. IT STILL LOOKS DRY...BUT PCPN CHANCES DO
EXIST JUST BEYOND THE FA...AND MAY END UP YIELDING A SMALL CHANCE
MENTION HERE OR THERE BEFORE ALL IS SAID AND DONE. STILL
LARGELY...THE DRY FORECAST SHOULD HOLD...AS WELL AS COLD...EVEN WITH
MODERATION...WITH TUE-WED HIGHS IN THE 30S AND LOWS IN THE TEENS.
LONGER RANGE INDICATORS SUGGEST A REINFORCED SHOT OF COLD TOWARD THE
END OF THE WEEK...WITH HIGHS BACK IN THE 20S AND LOWS IN THE SINGLE
DIGITS BY DAY 7 (OR 8).
&&
.AVIATION...
ISSUED AT 543 PM CST THU FEB 19 2015
THE 3KM HRRR MODEL GUIDANCE IS INITIALIZING A LITTLE FURTHER
SOUTHWEST THAN THE 0.5 DEGREE NWS RADAR MOSAIC REFLECTIVITY FOR
SNOW THIS AFTERNOON OVER MISSOURI. WILL BE WATCHING THE 18-25DBZ
BANDS FOR SATURATING THE MID-DECK FOR SNOW REACHING THE SURFACE.
AT THIS POINT, WILL WATCH THE EVOLUTION OF THE EASTWARD MOVING
SNOW BANDS FOR THE NEED TO ACCELERATE THE ONSET OF LOWER VFR
CEILINGS, ESPECIALLY AT KCGI/KPAH. OTHERWISE, DO NOT PLAN TO
INTRODUCE MVFR CEILINGS UNTIL AFTER 12Z, WITH THE ONSET OF SNOW
WITHIN 2-3 HOURS AFTER THE BEGINNING OF THE MVFR CEILINGS.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...WINTER STORM WATCH FROM FRIDAY AFTERNOON THROUGH LATE FRIDAY
NIGHT FOR ILZ075>078-080>094.
MO...WINTER STORM WATCH FROM FRIDAY AFTERNOON THROUGH LATE FRIDAY
NIGHT FOR MOZ076-086-087-100-107>112-114.
IN...WINTER STORM WATCH FROM FRIDAY AFTERNOON THROUGH LATE FRIDAY
NIGHT FOR INZ081-082-085>088.
KY...WINTER STORM WATCH FROM FRIDAY AFTERNOON THROUGH LATE FRIDAY
NIGHT FOR KYZ001>022.
&&
$$
UPDATE...SMITH
SHORT TERM...DRS/DH
LONG TERM...DH
AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
330 AM CST FRI FEB 20 2015
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 330 AM CST FRI FEB 20 2015
PCPN CHANCES AND PCPN TYPE TONIGHT ACROSS OUR SOUTHERN COUNTIES
AND TEMPERATURES FOR ALL OF THE AREA THE NEXT FEW DAYS WILL
PROVIDE THE MAIN FORECAST CHALLENGES.
LARGE SCALE PATTERN AT 500 MB FEATURES A TROUGH FROM THE EASTERN
PACIFIC UP INTO ALASKA. TWO CLOSED LOWS WERE NOTED...ONE OVER NEW
YORK STATE AND THE OTHER OVER THE NORTHERN PART OF HUDSON BAY. OUR
AREA WAS IN NORTHWEST FLOW. 12 HOUR HEIGHT FALLS OF UP TO 60 METERS
WERE NOTED LAST EVENING FROM EASTERN WASHINGTON STATE INTO WESTERN
MONTANA. THROUGH SATURDAY THE RIDGE TO THE WEST WILL AMPLIFY A
BIT AND MOVE EAST...THEN A REX BLOCK FORMS BY SUNDAY.
TODAY WILL BE FAIRLY MILD AS THE ARCTIC AIRMASS WHICH HAS BEEN
OVER OUR AREA THE PAST COUPLE OF DAYS HAS LOOSENED ITS GRIP. WITH
WINDS GETTING MORE OF A WESTERLY COMPONENT TODAY...MOST LOCATIONS
SHOULD TOP OUT IN THE 30S AND 40S. NORTHEAST NEBRASKA APPEARS TO
HAVE THE BEST CHANCE OF SEEING MID 40S OR POSSIBLY EVEN WARMER.
EXPECT MOST OF THE AREA TO HAVE A GOOD AMOUNT OF MID AND/OR HIGH
LEVEL CLOUDS WHICH WILL DAMPEN WARMING A BIT. THERE IS SOME
QUESTION WHETHER LIGHT PCPN WILL DEVELOP OVER PARTS OF SOUTHEAST
NEBRASKA THIS AFTERNOON. LATEST HRRR AND 13 KM RAP MODELS KEEP
THINGS DRY...SO WILL TREND THAT WAY FOR NOW EVEN THOUGH SOME OTHER
MODELS DO SHOW SOME LIGHT AMOUNTS ARE POSSIBLE. THIS MAY NEED SOME
ADJUSTMENT LATER TODAY.
WINDS WILL TURN TO THE NORTH OR NORTHWEST TONIGHT AS YET ANOTHER
COLD FRONT SAGS SOUTHWARD ACROSS THE REGION. SOME FLURRIES WILL BE
POSSIBLE LATER TONIGHT AND INTO SATURDAY...ESPECIALLY NORTH. THE
MAIN PCPN WILL STAY ACROSS KANSAS AND MISSOURI...BUT HELD ONTO SOME
CHANCE POPS IN OUR SOUTHERN COUNTIES TO BLEND IN WITH NEIGHBORS TO
THE SOUTH. NAM/GFS AND ECMWF ALL HINT AT SOME MIXED PCPN. ADDED A
SLIGHT CHANCE THIS EVENING UP AS FAR NORTH AS OMAHA/COUNCIL
BLUFFS. THE PCPN TYPE COULD BE RAIN OR SNOW EARLY ON...THEN A MIX
OF RAIN/FREEZING RAIN/SNOW DEPENDING ON SURFACE TEMPERATURES. THE
00Z GFS AND 06Z NAM MODELS SEEMED JUST A BIT OVERDONE WITH QPF
ALONG THE KANSAS AND MISSOURI BORDERS TONIGHT.
TEMPERATURES SHOULD SLOWLY SLIDE DURING THE DAY SATURDAY AS COLD AIR
SETTLES SOUTH AHEAD OF A 1045 MB HIGH THAT WILL BUILD INTO SOUTHERN
SASKATCHEWAN BY SATURDAY EVENING...THEN TO THE EASTERN DAKOTAS BY
SUNDAY EVENING. EXPECT HIGHS SUNDAY TO ONLY BE IN THE TEENS. LOWS
SATURDAY NIGHT WILL BE SINGLE DIGITS...THEN MAINLY AROUND ZERO TO 5
ABOVE FOR SUNDAY NIGHT.
.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 330 AM CST FRI FEB 20 2015
TEMPERATURES WILL START TO MODERATE MONDAY...WITH HIGHS IN THE 20S.
THAT TREND SHOULD CONTINUE TUESDAY WITH HIGHS IN THE 30S...BUT A
COLD FRONT WILL PUSH THROUGH IN THE AFTERNOON. THEN BELOW NORMAL
TEMPERATURES SHOULD LAST INTO LATE WEEK.
BOTH THE 00Z GFS AND 00Z ECMWF AGREE THAT SOME LIGHT SNOW MAY
DEVELOP AS EARLY AS WEDNESDAY BUT CHANCES ARE A BIT HIGHER FOR
WEDNESDAY NIGHT...ESPECIALLY FOR OUR WESTERN COUNTIES. NOT OVERLY
CONFIDENT ON THIS AND TIMING WILL PROBABLY NEED SOME ADJUSTMENT
WITH FUTURE FORECASTS.
&&
.AVIATION...(06Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 1114 PM CST THU FEB 19 2015
LOW LEVEL WIND SHEAR WILL BE THE INITIAL CONCERN WITH WINDS AT
2000 FEET AROUND 40 KNOTS. THAT EASES BY 13Z AS LOW LEVEL JET
WEAKENS. OTHERWISE...VFR CONDITIONS THROUGH THE PERIOD.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
SHORT TERM...MILLER
LONG TERM...MILLER
AVIATION...DEWALD
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
300 AM CST FRI FEB 20 2015
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 300 AM CST FRI FEB 20 2015
SNOW CHANCES TODAY AND TONIGHT WILL BE THE MAIN FORECAST
CHALLENGE...THEN WINDS TOMORROW.
NORTHWESTERLY FLOW ALOFT CONTINUES OVER THE NORTHERN PLAINS AND WV
LOOP SHOWS SEVERAL WEAK SHORTWAVES UPSTREAM. THE FIRST SHORTWAVE
CURRENTLY IS DIGGING INTO NORTHEASTERN SOUTH DAKOTA...AND THERE
HAS BEEN SOME LIGHT SNOW IN THE WARM AIR ADVECTION AHEAD OF THE
SFC LOW CURRENTLY ENTERING THE NORTHEASTERN CWA. THE LIGHT SNOW
HAS STARTED TO COME TO AN END ACROSS THE NORTHWESTERN
COUNTIES...SO THE TREND IN POPS TO PUSH HIGHEST PROBABILITIES OFF
TO THE EAST THIS MORNING SEEMS GOOD. THE RAP HAS THE NEXT WEAK
SHORTWAVES COMING THROUGH MAINLY ACROSS CENTRAL AND WESTERN
ND...WHICH FITS WITH CURRENT CANADIAN RADAR. MUCH OF THE SNOW FROM
THESE SHORTWAVES WILL REMAIN TO OUR WEST BUT CONTINUED TO KEEP
SOME LOW POPS IN OUR WESTERN COUNTIES IN CASE SOME LIGHT SNOW
CLIPS THAT AREA. WITH THE FIRST MORNING SHORTWAVE MOVING EAST AND
THE NEXT SHORTWAVES MAINLY FOCUSED ON THE FAR WESTERN TIER...THINK
THAT THERE WILL BE A PERIOD FOR THE CENTRAL CWA TODAY WHERE ONLY
LINGERING FLURRIES REMAINS. EVEN THOSE AREAS THAT GET ACCUMULATION
WILL SEE A HALF AN INCH AT MOST. THERE SHOULD BE ANOTHER LOW
CHANCE FOR ACCUMULATING SNOW AREAWIDE AS THE ARCTIC FRONT COMES
DOWN TONIGHT...BUT AGAIN IT WILL BE A DUSTING AT MOST.
TEMPS SHOULD BE FAIRLY MILD TODAY WITH GWINNER ALREADY AT 21
DEGREES AT 08Z. CONTINUED TO KEEP HIGHS IN THE TEENS IN THE NORTH
TO LOW 30S IN THE SOUTH. THE MILD TEMPS WILL END TONIGHT AS ARCTIC
AIR PLUNGES BACK SOUTH INTO THE CWA. WITH THE UPPER TROUGH DIGGING
DOWN OUT OF CANADA...ALL MODELS HAVE 850MB TEMPS BACK BELOW -20 C
FOR SATURDAY. CONTINUED TO KEEP HIGHS EITHER SIDE OF ZERO. WITH
COLD AIR ADVECTION AND A DECENT GRADIENT AHEAD OF THE ARCTIC
HIGH...NORTH WINDS COULD BECOME RATHER BREEZY SATURDAY. THE
BLOWING SNOW MODEL DOES NOT GIVE MUCH PROBABILITY DUE TO NO
FALLING SNOW AT THE TIME...BUT WILL HAVE TO WATCH WINDS ON
SATURDAY AS 925MB SPEEDS GET UP TO 25 KTS. THE WINDS WILL ALSO
KNOCK APPARENT TEMPS DOWN BELOW ADVISORY CRITERIA AT TIMES
ALTHOUGH TIMING IS STILL UNCERTAIN AT THIS POINT.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 300 AM CST FRI FEB 20 2015
SATURDAY NIGHT THROUGH SUNDAY NIGHT...CONDITIONS WILL REMAIN DRY
BUT COLD AS ARCTIC HIGH PRESSURE CONTINUES TO BUILD INTO THE AREA.
DEPENDING ON HOW MUCH WE CLEAR OUT...TEMPS SATURDAY NIGHT COULD
FALL BELOW 20 BELOW AND WITH SOME GRADIENT REMAINING...WIND CHILLS
MAY BE LOWER THEN 40 BELOW BY SUNDAY MORNING. THE SFC HIGH CENTER
BUILDING IN ON SUNDAY WILL CONTINUE WITH FRIGID TEMPS NOT RISING
INTO THE POSITIVE DIGITS. THE SFC HIGH WILL BEGIN TO SINK
SOUTHEASTWARD SUNDAY NIGHT AND WINDS WILL START PICKING UP WITH
SOME WARM AIR ADVECTION LATE IN THE NIGHT. TEMPS MAY START RISING
IN THE WEST...BUT NOT BEFORE BOTTOMING OUT IN THE TEENS BELOW
ZERO.
MONDAY THROUGH THURSDAY...THE EXTENDED BEGINS WITH A PAIR OF UPPER LEVEL
DISTURBANCES UPSTREAM IN CENTRAL CANADA. THE FIRST/WEAKER WAVE MAY
BRING A FEW FLURRIES TO THE AREA MONDAY AFTERNOON/EVENING...BUT A
BETTER CHANCE LOOKS TO COME LATER IN THE NIGHT WITH THE SECOND
WAVE. STILL...MOISTURE LOOKS LIMITED. SURFACE WINDS WILL BE
SOUTHWESTERLY ON MONDAY AHEAD OF A COLD FRONT ASSOCIATED WITH THE
SURFACE LOW PRESSURE SYSTEM. TEMPS AT 850 MB WARM CONSIDERABLY
FROM SUNDAY MORNING TO MONDAY MORNING... NEARLY 20C IN 30 HRS. THE
RESULT WILL BE HIGHS ABOUT 30 DEGREES WARMER ON MONDAY THAN ON
SUNDAY. THE COLD FRONT WILL THEN BARREL THROUGH THE AREA ON
TUESDAY MORNING. THE GOOD NEWS IS THAT IT IS EXPECTED TO BE A
GLANCING BLOW...WITH THE COLDEST AIR OFF TO THE EAST OVER FAR NE
MN AND LAKE SUPERIOR. THE BAD NEWS IS THAT STAGNANT COLD HIGH
PRESSURE WILL SET UP OVER THE NORTHERN PLANS TO END THE WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1139 PM CST THU FEB 19 2015
2-5SM IN LIGHT SNOW IN THE RRV INTO NW MN OVERNIGHT GRADUALLY
ENDING TO JUST SOME FLURRIES. CIGS AN ISSUE AS SHOULD GO DOWN INTO
THE MVFR RANGE 1500-2500FT AGL AND STAY THAT WAY THROUGH THE
BALANCE OF FRIDAY. SOUTH WINDS WITH GUSTS TO 25 KTS IN THE RRV WILL
TURN WEST AND NORTHWEST LATE TONIGHT INTO FRIDAY BUT REMAIN IN THE
10-15 KT RANGE.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
SHORT TERM...JR
LONG TERM...JR/KNUTSVIG
AVIATION...RIDDLE
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1144 PM CST THU FEB 19 2015
.UPDATE...
ISSUED AT 1139 PM CST THU FEB 19 2015
NO ADDITIONAL CHANGES NEEDED. RADAR ESTIMATES FOR SNOW SHOW ONE
QUARTER TO THREE QUARTERS INCH ACROSS ERN ND WHICH SEEMS
REASONABLE. SNOW IS VERY FINE BUT BLOWING/DRIFTING AROUND SOME ESP
IN THE NRN VALLEY WHICH WAS ANTICIPATED. WINDS WILL DIMINISH LATER
TONIGHT.
UPDATE ISSUED AT 937 PM CST THU FEB 19 2015
SYSTEM MOVING THROUGH IS VERY UNIMPRESSIVE ON RADAR AND
OBSERVATIONS/WEBCAMS. A DUSTING IN DEVILS LAKE (MAYBE A FEW
TENTHS) BUT SNOW APPEARS VERY FINE. RAP MODEL DOESNT HAVE ANY
CONCENTRATED FRONTOGENSIS AND MAIN WARM ADV AT 850 IS WELL SOUTH
OF THE STATE. NET RESULT IS ENOUGH MOISTURE AND WEAK LIFT FOR
LIGHT PRECIP BUT NOTHING TO ENCOURAGE BIGGER SNOW FLAKE GROWTH. SO
TRIMMED SNOW TOTALS TO UNDER 1 INCH.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 300 PM CST THU FEB 19 2015
THE MAIN CHALLENGE WILL BE LIGHT SNOW TONIGHT INTO FRI...THEN
BITTERLY COLD WIND CHILLS DEVELOPING SATURDAY INTO SUNDAY. MODELS
ARE IN GOOD AGREEMENT...SO CONFIDENCE IS FAIRLY HIGH WITH THIS
FORECAST.
FOR TONIGHT...A BAND OF LIGHT SNOW WILL SLOWLY MOVE FROM WEST TO
EAST WITHIN MID LEVEL WAA/ISENTROPIC LIFT. THERE IS A FAIRLY
CONCENTRATED AREA OF LIFT...BUT IT ONLY LASTS FROM 3-6HR. THIS
COUPLED WITH THE FACT THAT WE ARE IN FAST NW FLOW ALOFT...AND MID
LEVEL LAPSE RATES ARE FAIRLY STABLE...NOT EXPECTING MUCH IN THE
WAY OF PERSISTENT MESOSCALE BANDING. THE BEST CHANCE FOR AN INCH
OR SO SHOULD BE IN THE NORTH INTO NW MN. THERE WILL ALSO BE
SOUTHERLY WINDS THAT COULD SUSTAIN NEAR 20KT IN THE NORTHERN
VALLEY FROM 00-06Z...SO IF THIS OCCURS WITH LIGHT SNOW THEN PATCHY
BLOWING SNOW IS SUGGESTED WITH THE CANADIAN BLOWING SNOW MODEL.
THEREFORE...WILL ADD SOME PATCHY BLOWING SNOW IN THE NORTH VALLEY
FROM 00-06Z. TEMPS WILL SLOWLY RISE OVERNIGHT...ALTHOUGH WITH
SOUTHERLY WINDS IT WILL NOT FEEL WARM AT ALL...EVEN THOUGH WE
SHOULD REMAIN OUT OF WIND CHILL CRITERIA.
ON FRIDAY...A SFC LOW MOVES THROUGH IN THE MORNING WITH COLD
ADVECTION DEVELOPING BY AFTERNOON FROM NORTH TO SOUTH. THERE WILL
BE DEEP LAYERED SATURATION...AND SOME LIFTING NEAR SEVERAL
SHORTWAVES SO THE CONTINUATION OF LIGHT SNOW/SNOW SHOWERS IS
POSSIBLE. NOT EXPECTING MUCH ADDITIONAL ACCUMULATION THOUGH.
FOR FRI NIGHT...TEMPS WILL FALL BEHIND A STRONG COLD FRONT AND
THERE COULD BE SOME DRIFTING/PATCHY BLOWING SNOW IN OPEN AREAS.
WILL NOT MENTION FOR NOW SINCE THIS WILL DEPEND ON HOW STRONG
WINDS GET...BUT SOMETHING TO MONITOR. WIND CHILLS MAY FALL INTO
THE 25 TO 30 BELOW RANGE LATE AT NIGHT AND THAT WILL BE THE MAIN
HAZARD.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 300 PM CST THU FEB 19 2015
FOR SAT THROUGH SUNDAY...A BITTERLY COLD AIRMASS WILL BE OVER THE
REGION WITH 925MB TEMPS DOWN TO AROUND -30C BY SAT AFTERNOON. THIS
COUPLED WITH STRONG NORTHERLY WINDS AROUND 15-20KT INTO SAT NIGHT
WILL PRODUCE BITTERLY COLD WIND CHILLS TO AT LEAST 40
BELOW...PERHAPS TO 45 BELOW LATE SAT NIGHT. NEEDLESS TO
SAY...WIND CHILL HEADLINES WILL BE NEEDED AS WE HEAD TOWARD THE
WEEKEND. THERE COULD EVEN BE SOME FLURRIES/SNOW SHOWERS ON SAT
ALONG WITH PATCHY BLOWING SNOW IN PRONE AREAS SAT NEAR ANY SNOW
SHOWERS...SO SOMETHING WE WILL MONITOR. ACTUAL AIR TEMPS WILL
LIKELY REMAIN BELOW ZERO SAT AND SUNDAY...WITH LOWS SAT NIGHT 20
TO 25 BELOW ALONG WITH DANGEROUS WIND CHILLS. IT SHOULD BE DRY
SUNDAY ALTHOUGH VERY COLD WITH ARCTIC HIGH PRESSURE MOVING
OVERHEAD.
FOR SUN NIGHT THROUGH THU...ARCTIC HIGH WILL MOVE OUT OF THE
REGION SUN NIGHT AND WESTERLY FLOW WILL PROVIDE A BRIEF WARM UP ON
MONDAY...WITH DAYTIME HIGHS IN THE 20S WEST AND MID TEENS EAST.
FOLLOWING THAT...A NORTHERLY UPPER FLOW PATTERN DOMINATES THE
WEEK...WITH AN UPPER HIGH OVER HUDSON BAY KICKING OFF A SHORT WAVE
THAT WILL ROTATE THROUGH OUR REGION MON NIGHT INTO TUE. THE
INCREASED CLOUD COVER WILL KEEP MODERATE OVERNIGHT TEMPS MON NIGHT
AND DAYTIME HIGHS TUESDAY IN THE MID TEENS. ANOTHER ARCTIC AIRMASS
DROPS IN FROM THE YUKON TERRITORY ON TUE NIGHT...BRINGING SUB ZERO
LOWS AND SINGLE DIGIT HIGHS BACK TO THE REGION FOR THE LATTER PART
OF THE WORK WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1139 PM CST THU FEB 19 2015
2-5SM IN LIGHT SNOW IN THE RRV INTO NW MN OVERNIGHT GRADUALLY
ENDING TO JUST SOME FLURRIES. CIGS AN ISSUE AS SHOULD GO DOWN INTO
THE MVFR RANGE 1500-2500FT AGL AND STAY THAT WAY THROUGH THE
BALANCE OF FRIDAY. SOUTH WINDS WITH GUSTS TO 25 KTS IN THE RRV WILL
TURN WEST AND NORTHWEST LATE TONIGHT INTO FRIDAY BUT REMAIN IN THE
10-15 KT RANGE.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...RIDDLE
SHORT TERM...DK
LONG TERM...DK/SPEICHER
AVIATION...RIDDLE
AREA FORECAST DISCUSSION
NWS ABERDEEN SD
345 AM CST FRI FEB 20 2015
.SHORT TERM...TODAY THROUGH SUNDAY
AS OF 9Z...A SURFACE LOW PRESSURE SYSTEM IS LOCATED OVER NORTHERN
NORTH DAKOTA. THE WARM FRONT ASSOCIATED WITH THE LOW PRESSURE IS
ALONG THE MISSOURI RIVER. THE WARM FRONT WILL PUSH EAST TODAY
ALLOWING FOR ABOVE NORMAL TEMPERATURES TO SPREAD ACROSS THE CWA.
THE PAST FEW RUNS OF THE HRRR AND RAPID REFRESH...PLUS THE NSSL
WRF ALL SUPPORT HIGHS IN THE MID 40S TO THE MID 50S FOR NORTH
CENTRAL AND CENTRAL SOUTH DAKOTA. COOLER TEMPERATURES ARE EXPECTED
IN NORTHEASTERN SOUTH DAKOTA AND WESTERN MINNESOTA.
A COLD FRONT...CURRENTLY OVER SOUTHERN CANADA...WILL SLIDE
SOUTHWARD ACROSS THE CWA LATER THIS AFTERNOON. LIGHT PRECIPITATION
IS POSSIBLE ALONG THIS FRONT...HOWEVER CHANCES APPEARS BETTER POST
FRONTAL...OR WITH THE CAA. PRECIPITATION AMOUNTS SHOULD BE RATHER
LIGHT. COLD AIR ADVECTION...THANKS TO AN ARCTIC HIGH
PRESSURE...WILL CONTINUE THROUGH SUNDAY WITH TEMPERATURES BECOMING
PROGRESSIVELY COLDER. HIGHS ON SATURDAY WILL RANGE FROM THE SINGLE
DIGITS...TO THE MID 20S. HIGHS BY SUNDAY WILL LIKELY RANGE FROM
THE SINGLE DIGITS BELOW ZERO...IN NORTHEASTERN SOUTH DAKOTA...TO
THE MID TEENS IN CENTRAL SOUTH DAKOTA.
.LONG TERM...SUNDAY NIGHT THROUGH THURSDAY
VERY GOOD AGREEMENT WITH ALL OF THE MODELS IN THE LONG TERM. THE
PERIOD BEGINS WITH ARCTIC HIGH PRESSURE CENTERED OVER EASTERN SD
BUILDING SOUTHEAST THROUGH SUNDAY NIGHT. AFTER A COLD SUNDAY
NIGHT...SOUTHWEST WINDS ON THE BACKSIDE OF THIS SURFACE HIGH WILL
BRING IN WARMER AIR WITH TEMPERATURES WARMING UP TO NEAR NORMAL BY
LATE MONDAY AFTERNOON. MONDAY NIGHT WILL BE MILD WITH PACIFIC AIR
MOVING ACROSS THE REGION ON WEST WINDS. TUESDAY WILL REMAIN NEAR
NORMAL FOR HIGHS WITH A TROUGH COMING THROUGH AS WINDS TURN
NORTHWEST AND INCREASE. AN ARCTIC BOUNDARY WILL THEN PUSH THROUGH
LATE TUESDAY AFTERNOON AND EVENING. ARCTIC AIR WILL REMAIN OVER
THE REGION THROUGH THURSDAY WITH MUCH BELOW NORMAL TEMPERATURES.
THE MODELS ALL SHOW A CLIPPER SYSTEM DROPPING SOUTHEAST ALONG THE
ARCTIC BOUNDARY LATE TUESDAY NIGHT THROUGH WEDNESDAY NIGHT. AT
THIS TIME THEY ALL SHOW SOME SNOW WITH THIS SYSTEM MAINLY ACROSS
THE WESTERN CWA. THUS...INCREASED POPS SOME AND MAY HAVE TO
INCREASE THEM MORE IN LATER FORECASTS.
&&
.AVIATION...
06Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
VFR CONDITIONS WILL PREVAIL ACROSS THE AREA TONIGHT. WHILE RADAR
IS SHOWING RETURNS OVER SD LITTLE TO NOTHING IS MAKING IT THROUGH
THE VERY DRY LAYER FROM THE SFC UP TO 3500 FT. BEST CHANCES ARE
ACROSS WEST CENTRAL MN. MVFR CIGS WILL MOVE IN ON NORTHWEST FLOW
BEHIND THE FRONT FRIDAY MORNING/AFTERNOON.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
SHORT TERM...SD
LONG TERM...MOHR
AVIATION...WISE
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1040 PM CST THU FEB 19 2015
.UPDATE...
ISSUED AT 912 PM CST THU FEB 19 2015
WILL CONTINUE TO CUT BACK POPS TONIGHT...AS DRY AIR NOT BEING
OVERCOME. WILL BE HARD TO GET MUCH MORE THAN A PERIOD OF SCATTERED
FLURRIES. IF ANYONE WILL BE ABLE TO SQUEAK OUT A FEW TENTHS IT
WILL PROBABLY BE OUR FAR EASTERN COUNTIES FROM MARSHALL TO
SPENCER.
WILL BE INTERESTING TO SEE WHAT HAPPENS TOMORROW. SHOULD BE A
WARM DAY WITH WARMING TEMPERATURES ALOFT AND GOOD MIXING. HOWEVER
WILL HAVE TO WATCH THE ABUNDANCE OF STRATUS CURRENTLY SEEN OVER
NORTH DAKOTA AND SOUTHERN CANADA. THE RAP HAS A DECENT HANDLE ON
THIS AND SUGGESTS IT WILL MOVE SOUTH INTO THE NORTHEAST HALF OF
OUR CWA TOMORROW. IF THIS WERE TO HAPPEN IT WOULD LIKELY HOLD
TEMPERATURES DOWN QUITE A BIT. WILL NOT MAKE ANY CHANGES NOW...BUT
SOMETHING FOR THE OVERNIGHT SHIFT TO MORE CLOSELY EXAMINE.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 330 PM CST THU FEB 19 2015
WARM FRONT IS PRESSING EASTWARD AT THIS TIME. IN FACT CHAMBERLAIN IS
UP CLOSE TO 30 DEGREES WITH WINNER AT 34 MID THURSDAY AFTERNOON. IN
THE NEAR TERM AND FOR TONIGHT...BELIEVE THAT MANY GUIDANCE VALUES
ARE TOO COLD...IN SOME CASES WAY TOO COLD. NOT SURE WHY TEMPERATURES
WOULD PLUMMET ALL THAT MUCH WITH THIS KIND OF SOUTHERLY FLOW AND THE
WARM FRONT NOT STALLING. THEREFORE TRENDED TOWARD THE WARMER
READINGS WHICH WERE RAW ECMWF VALUES BLENDED WITH MOS CONSENSUS. NOW
ONTO THE WARM FRONTAL SNOW...WHICH HAS SO FAR BEEN TOTALLY NON
EXISTENT IN OUR WESTERN ZONES. BONE DRY AIR IN THE LOW LEVELS...
WITNESSED BY CURRENT SURFACE DEW POINT READINGS STILL HOVER NEAR
ZERO AND SINGLE DIGITS BELOW ZERO ALONG AND EAST OF THE JAMES RIVER
VALLEY...HAS NOT ALLOWED ANYTHING TO REACH THE GROUND. SOME LOW
LEVEL MOISTURE RETURN MAY INCREASE GENERALLY EAST OF I 29 THIS
EVENING AND OVERNIGHT. BUT SNOW AMOUNTS WILL BE LIGHT. WITH THE GFS
NOT SHOWING ANY MEASURABLE PRECIP FOR OUR FORECAST AREA...STILL DID
NOT GO CATEGORICAL POPS EVEN EAST OF I 29...BUT KEPT POPS IN THE
LIKELY CATEGORY FOR THOSE ZONES.
BEHIND THE WARM FRONT..FRIDAY WILL BE MILD. BLENDED THE MOS
CONSENSUS WITH THE RAW ECMWF AND GEM GLOBAL AS 925MB TEMPERATURES
CERTAINLY SUPPORT READINGS WELL INTO THE 30S AND 40S.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 330 PM CST THU FEB 19 2015
COLDER AIR WILL BEGIN FILTERING IN FRIDAY NIGHT BEHIND A BROAD AND
DIFFUSE FRONT. LOW LEVEL MOISTURE SHOULD BE FAIRLY COPIOUS WITH AND
BEHIND THE FRONT AND EXPECT A FEW FLURRIES OVER THE AREA. WILL ALSO
KEEP THAT SLIGHT CHANCE OF MEASURABLE SNOW OVER THE SOUTHWEST CORNER
FOR SATURDAY MORNING. MEANWHILE STRONG CANADIAN HIGH PRESSURE WILL
BE APPROACHING SATURDAY WITH SUBSIDENCE AND RESULTING DRYING
CLEARING OUT SKIES AND ANY FLURRIES FROM THE NORTH/NORTHEAST.
TEMPERATURES WHICH WILL COOL STEADILY BUT MODESTLY INTO THE TEENS
AND 20S FRIDAY NIGHT WILL NOT BE ABLE TO RISE MUCH SATURDAY DESPITE
THE CLEARING SKIES.
THE COLD AIR WILL CONTINUE TO FLOW IN SATURDAY NIGHT INTO SUNDAY
UNDER GENERALLY CLEAR SKIES. ANOTHER GENUINE WIND CHILL ADVISORY
EVENT SEEMS LIKELY BY SUNDAY MORNING...AT LEAST IN OUR NORTH AND
EAST. ACTUAL TEMPERATURES WILL DROP INTO THE SINGLE DIGITS BY SUNDAY
MORNING...BELOW ZERO NORTHEAST TO ABOVE ZERO SOUTHWEST. SUNDAY HIGHS
WILL WARM UNDER THE STRONG LATE FEBRUARY SUNSHINE TO THE SINGLE
DIGITS ABOVE ZERO NORTHEAST TO THE TEENS SOUTHWEST.
THE COLD HIGH WILL MOVE OVER THE AREA SUNDAY NIGHT BRINGING OF
COURSE COLD TEMPERATURES WITH LIGHT WINDS. MONDAY WILL BE A WARMING
DAY WITH AN UNFAVORABLE PATTERN AND DRY AIR COMBINING FOR NO REAL
LIGHT SNOW CHANCE. ANOTHER COLD SHOT SHOULD BEGIN TO ARRIVE TUESDAY
THOUGH THE DAY SHOULD STILL BE FAIRLY MILD...AND WILL GO WITH SOME
SMALL MENTION OF LIGHT SNOW AS PER EXTENDED GUIDANCE.
WEDNESDAY AND THURSDAY WILL SEE A PROCESSION OF UPPER WAVES WHICH
WILL STRENGTHEN/REINFORCE THE NEWEST COLD AIR PUSH...WHILE POSSIBLY
BRINGING A FEW AREAS OF LIGHT SNOW OR FLURRIES...BUT NOTHING VERY
BIG. THE MAIN QUESTION IS THE STRENGTH OF THIS PUSH WHICH HAS BEEN
CHANGING SOMEWHAT IN MODEL SOLUTIONS FROM RUN TO RUN. THE EXTENDED
GUIDANCE TAKES HIGH TEMPERATURE BACK DOWN TO TEENS AND 20S FOR
WEDNESDAY AND THURSDAY. THE 12Z GFS AND EC SUGGEST A STRONGER COLD
INVASION. WILL GO WITH THE GUIDANCE FOR NOW AND CHECK TO SEE IF THIS
SOLUTION REMAINS FOR THE NEXT COUPLE RUNS. ALSO...IF WE DONT GET
BETTER SNOW COVER IN THE NEXT FEW DAYS...SOME OF THE THE BITE WILL
REMAIN OFF THE OUTBREAK. HOWEVER...IT IS LOOKING LIKE GETTING MORE
THAN A DAY OF ABOVE OR EVEN NEAR NORMAL TEMPERATURES IS OUT OF THE
QUESTION AT LEAST UNTIL MARCH BEGINS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY EVENING)
ISSUED AT 1040 PM CST THU FEB 19 2015
MAINLY EXPECTING VFR CONDITIONS THROUGH THE NIGHT AT TAF SITES.
LIGHT SNOW AND FLURRIES STILL HAVING A TOUGH TIME REACHING THE
GROUND...BUT STILL MAY GET A BRIEF PERIOD OF MVFR VIS EAST OF
INTERSTATE 29 IN LIGHT SNOW. OTHERWISE SIGNS THAT LOWER MVFR STRATUS
CURRENTLY OVER NORTH DAKOTA AND CANADA WILL TRY TO WORK SOUTH BEHIND
THE COLD FRONT AFTER 12Z FRIDAY. STILL QUITE A BIT OF UNCERTAINTY ON
HEIGHT AND COVERAGE OF THIS STRATUS...BUT ENOUGH CONFIDENCE THAT
DECIDED TO INTRODUCE A PERIOD OF MVFR CIGS AT KHON AND KFSD FRIDAY
MORNING. EXPECT THIS SHOULD INCREASE BACK TO VFR BY AFTERNOON AT THE
TAF SITES...ALTHOUGH LOWER CIGS COULD LINGER OVER SOUTHWEST
MINNESOTA. WILL NEED TO CONTINUE TO MONITOR TRENDS IN THE
OBSERVATIONS AND FUTURE MODEL RUNS. SECONDARY COLD FRONT MOVING
THROUGH FRIDAY EVENING MAY BRING A RETURN TO THE MVFR CIGS.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
UPDATE...CHENARD
SHORT TERM...MJ
LONG TERM...
AVIATION...CHENARD
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
328 AM MST FRI FEB 20 2015
.SHORT TERM...(TODAY THROUGH TONIGHT )
ISSUED AT 325 AM MST FRI FEB 20 2015
A DISTURBANCE IN NW FLOW ALOFT WILL MOVE ACROSS THE AREA THIS AFTN
WITH DECENT MID LVL QG ASCENT AND STEEP LAPSE RATES. SNOW WILL
INCREASE IN THE MTNS BY MIDDAY WITH A GOOD CHC OF RAIN SHOWERS BY
AFTN OVER THE PLAINS. WITH RATHER UNSTABLE AIRMASS COULD SEE SOME
THUNDER AS WELL.
FOR TONIGHT THE FIRST DISTURBANCE WILL MOVE EAST OF THE AREA WITH
MID LVL DESCENT THRU THE EVENING HOURS SO MAY SEE A DECREASE IN PCPN
ACTIVITY. HOWEVER ANOTHER FEATURE WILL MOVE INTO THE AREA AFTER
MIDNIGHT ALONG WITH A DECENT SHOT OF MID LVL ASCENT AND FAVORABLE
LAPSE RATES. THUS WOULD EXPECT SNOW TO INCREASE IN THE MTNS. OVER
NERN CO A CDFNT WILL MOVE SOUTHWARD ACROSS THE PLAINS THIS EVENING
WHICH BRIEFLY ENHANCE UPSLOPE FLOW BY MIDNIGHT. ONE WOULD THINK
THERE SHOULD BE SOME INCREASE IN PCPN OVERNIGHT OVER PORTIONS OF
NERN CO AND THE FOOTHILLS AS THE NEXT WAVE AND SHOT OF QG ASCENT
MOVES ACROSS. HOWEVER NEITHER THE NAM OR GFS SHOW A LOT OF QPF WITH
AMOUNTS A QUARTER INCH OR LESS OVER NERN CO. SREF PLUME GUIDANCE
ALSO IS ALSO UNDER A QUARTER OR AN INCH SO IF THIS IS THE CASE SNOW
AMOUNTS WOULD MAINLY BE IN THE 1 TO 3 INCH RANGE WITH SLIGHTLY
HIGHER AMOUNTS POSSIBLE IN THE FOOTHILLS.
AT THIS POINT CONFIDENCE OF ISSUING A WARNING FOR THE FOOTHILLS AND
ADJACENT PLAINS FOR TONIGHT IS NOT HIGH SINCE IT APPEARS BEST CHC OF
SNOW MAY NOT OCCUR UNTIL MIDNIGHT OR LATER SO WILL DEFER DECISION TO
DAY SHIFT AND DELAY ONSET OF WATCH. IN THE MTNS WILL START A
WARNING BY EARLY AFTN AND KEEP A WATCH IN PLACE FOR ZNS 30 AND 32.
MEANWHILE BEST CHC OF SNOW FOR ZN 37 LOOKS TO BE ON SAT SO WILL
DEFER WATCH TO 12Z SAT.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 325 AM MST FRI FEB 20 2015
WINTER WEATHER TO MAKE A STRONG COMEBACK THIS WEEKEND WITH COLDER
TEMPERATURES AND SIGNIFICANT SNOWFALL EXPECTED FOR PORTIONS OF
CWA. APPEARS THE BEST POTENTIAL FOR THE HEAVIEST AND MOST
WIDESPREAD SNOWFALL WILL BE ON SATURDAY AFTERNOON AND SATURDAY
NIGHT. EXPECT INCREASING QG ASCENT SATURDAY MORNING AS BROAD LOW
PRESSURE CONTINUES TO DEVELOP AND BECOME MORE ELONGATED OVER THE
GREAT BASIN. A REINFORCING SHOT OF COLDER AIR MOVES IN SATURDAY
NIGHT WITH ENHANCED UPSLOPE FLOW TO GO ALONG WITH THE VERTICAL
ASCENT AND STEEP LAPSE RATES. THE TROF DEVELOPS INTO A CLOSED LOW
WAY WEST OVER CALIFORNIA ON SUNDAY WITH A RESULTANT STRONG
WESTERLY FLOW ALOFT AND A STRONG JET ALOFT WHICH SHIFTS NORTH
ACROSS EASTERN COLORADO SATURDAY NIGHT AND SUNDAY. THIS COULD
INCREASE CHANCES OF HEAVIER BANDED SNOWFALL. HOWEVER THE LOW LEVEL
FLOW SHIFTS TO THE SOUTHEAST WHICH WOULD BE MORE DOWNSLOPE FLOW
OVER MUCH OF NORTHEAST COLORADO. EXPECT THE HEAVIER SNOWFALL TO BE
MORE LOCALIZED WITH THE JET AND OVER ENHANCED TERRAIN THAT FAVORS
SOUTHEAST FLOW.
AS FOR THE WINTER STORM WATCH...HAVE OPTED TO KEEP IT IN PLACE AND
BACK OFF ON THE ENDING OF THE WATCH. FOR NOW HAVE REMOVED THE
WATCH FROM SUNDAY NIGHT AND MONDAY AM GIVEN THE LONGEVITY OF THE
WATCH PERIOD. CERTAINLY THERE COULD BE SOME SNOW IN THOSE
PERIODS BUT WOULD PREFER TO KEEP THE WATCH WITH TIME PERIOD OF THE
MOST SIGNIFICANT POTENTIAL SNOWFALL. HAVE ALSO DELAYED THE WATCH
UNTIL SATURDAY AFTERNOON OVER THE FAR EASTERN PLAINS/PALMER DIVIDE
WITH THE NEXT WAVE APPROACHING. MODELS CONTINUE TO FOCUS THE
HEAVIEST SNOW OVER THE FRONT RANGE FOOTHILLS AND STRETCHING SOUTH
AND EAST THROUGH THE PALMER DIVIDE.
THE SNOW WILL CONTINUE TO DIMINISH LATE SUNDAY NIGHT AND MONDAY AS
THERE IS WEAK RIDGING THAT DEVELOPS OVER COLORADO FROM THE LOW
PRESSURE OVER CALIFORNIA. SLOW MODERATION IN TEMPERATURES THROUGH
THE MIDDLE OF NEXT WEEK AS THERE WILL BE QUITE A BIT OF SNOW ON
THE GROUND. NEXT STORM SYSTEM MOVES IN WEDNESDAY NIGHT AND
THURSDAY WITH NEXT CHANCE OF SNOW AND COLDER TEMPERATURES. STORM
TOTALS THROUGH THIS WEEKEND LOOK TO BE AROUND 7 TO 14 INCHES WITH
HIGHER AMOUNTS IN THE FOOTHILLS AND PALMER DIVIDE. LESSER AMOUNTS
OVER THE FAR NORTHEAST PLAINS.
&&
.AVIATION...(FOR THE TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 325 AM MST FRI FEB 20 2015
A WEAK BNDRY HAS MOVED ACROSS THE AIRPORT EARLY THIS MORNING WITH
NNE WINDS. HRRR SHOWS WINDS MAINLY VARIABLE THRU MID MORNING AND
THEN BECOMING LIGHT SLY BY 16Z. IN THE AFTN EXPECT A BAND OF
SHOWERS TO MOVE ACROSS WHICH MAY BE ACCOMPANIED BY GUSTY NWLY
OUTFLOW WINDS FOR AN HOUR OR SO. IN ADDITION WITH DECENT LAPSE
RATES IN PLACE CAN`T RULE OUT SOME THUNDER AS WELL. BY EARLY
EVENING A CDNFT WILL MOVE ACROSS THE AREA BY 02Z 03Z WITH GUSTY NLY
WINDS FOR A FEW HOURS. SHOULD SEE SNOW GRADUALLY DVLP BY 06Z WITH
A CONTINUATION THRU 12Z. FOR NOW WILL KEEP AMOUNTS IN THE 1 TO 2
INCH RANGE. HEAVIER SNOWFALL WILL BE POSSIBLE SAT AFTN INTO SAT
NIGHT.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WATCH FROM LATE TONIGHT THROUGH SUNDAY AFTERNOON
FOR COZ037.
WINTER STORM WATCH FROM THIS EVENING THROUGH SUNDAY AFTERNOON
FOR COZ035-036-038>045-049.
WINTER STORM WARNING FROM 2 PM THIS AFTERNOON TO 11 AM MST
SUNDAY FOR COZ031-033-034.
WINTER STORM WATCH FROM THIS AFTERNOON THROUGH SUNDAY MORNING
FOR COZ030-032.
WINTER STORM WATCH FROM SATURDAY MORNING THROUGH SUNDAY
AFTERNOON FOR COZ046-047.
&&
$$
SHORT TERM...RPK
LONG TERM...ENTREKIN
AVIATION...RPK
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
554 AM CST FRI FEB 20 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 423 AM CST FRI FEB 20 2015
TODAY WILL BE THE ODD WARM DAY IN AN OTHERWISE COLD PATTERN AS WE
GET INTO THE WARM SECTOR OF A CLIPPER THAT WAS OVER NE NODAK AT 330
THIS MORNING. THIS CLIPPER WILL SCOOT ACROSS THE INTERNATIONAL
BORDER TODAY...WITH A BRIEF HIT OF MILDER AIR MOVING THROUGH TODAY
OUT AHEAD OF THE NEXT ARCTIC COLD FRONT...WHICH WILL QUICKLY MOVE
BACK ACROSS THE AREA TONIGHT. BAND OF WAA SNOW MOVING ACROSS THE
AREA THIS MORNING IS TIED TO LIFT ON THE 290K ISENTROPIC SFC.
FOLLOWED SREF PROBS FAIRLY CLOSE FOR WORKING THIS BAND EAST ACROSS
MN THIS MORNING. LIGHT SNOW WILL LIKELY LINGER THROUGH MUCH OF
THE AFTERNOON ACROSS WI AS THEY WILL STAY TO THE NORTH OF THE
WARM/OCCLUDED FRONT. HOWEVER...QPF...EVEN IN WI LOOKS TO REMAIN
UNDER A 0.10"...WHICH STILL LEAVES US IN LINE FOR 0.5" TO 1.5" OF
SNOW. ALTHOUGH AMOUNTS WILL BE MINIMAL...SHOULD BE ENOUGH TO LEAD
TO A SLOWER COMMUTE THIS MORNING IN THE TWIN CITIES THANKS TO
TEMPERATURES STILL IN THE SINGLE DIGITS.
BY THE AFTERNOON THE SNOW WILL BE DONE FOR MOST OF MN...WITH SOME
FLURRIES LIKELY RETURNING IN THE WAKE OF THE COLD FRONT THIS
EVENING. CAA WILL RESULT IN STEEP LAPSE RATES...WHILE TEMPERATURES
WILL BE COLD ENOUGH THAT MUCH OF THE ATMO AND THEREFORE CLOUDS WILL
BE WITHIN THE DENDRITIC GROWTH ZONE...SO WILL NOT TAKE MUCH TO
GENERATE FLURRIES ACROSS THE AREA TONIGHT.
DID NOT CHANGE MUCH WITH THE GOING FORECAST IN TERMS OF HIGHS FOR
TODAY AS TEMPERATURES IN SW MN ARE ALREADY IN THE UPPER TEENS...SO
THERE THEY SHOULD HAVE NO PROBLEM WARMING THAT EXTRA 10-15 DEGREES
TO GET INTO THE 30S THIS AFTERNOON. THERE IS ALSO POTENTIAL THAT WE
MAY NOT BE WARM ENOUGH IN SW AND SC MN IF THEY MANAGE TO GET INTO
SOME SUNSHINE THIS AFTERNOON...WHICH IS PLAUSIBLE CONSIDERING SKIES
ARE MOSTLY CLEAR AT THE MOMENT WHEN YOU GET INTO NE NEB...SO WE
WILL HAVE TO SEE IF THAT CLEARING CAN FOLLOW THE WARM FRONT UP INTO
SRN MN.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 423 AM CST FRI FEB 20 2015
THE TREND IS THE SAME IN THE LONG TERM WITH DRY AND COLD WEATHER
EXPECTED THROUGH THE FORECAST PERIOD AND BEYOND. THE LONG WAVE
RIDGE-TROUGH-RIDGE PATTERN STRETCHING FROM THE EASTERN PACIFIC TO
WESTERN ATLANTIC REMAINS IN PLACE THROUGH THE NEXT 7-10 DAYS OFF.
THERE IS GOOD CONSISTENCY AMONG THE OPERATIONAL AND ENSEMBLE
GFS/ECMWF WITH THE LONG WAVE EVOLUTION OVER THE PAST FEW RUNS.
THIS MEANS THE UPPER MISSISSIPPI VALLEY /AND MOST OF THE CONUS FOR
THAT MATTER/ WILL REMAIN FIRMLY UNDER THE UPPER TROUGH AND
CONTINUE TO SEE TEMPS 15 TO 30 BELOW NORMAL FOR THE SECOND HALF OF
FEBRUARY. WE`RE SLOWLY GAINING GROUND ON THE EXCEPTIONAL COLD
FEBRUARY WE HAD IN 2014...WHERE A LOT OF LOCATIONS IN MN/WI WERE
CLOSE TO -12 DEGREES FOR THE MONTHLY DEPARTURE. AS OF THIS
MORNING...MSP/STC/EAU WERE -6.9/-5.6/-8.4 RESPECTIVELY FOR THE
TEMPERATURE DEPARTURE SO FAR THIS MONTH. WE LOWERED OUR MONTHLY
DEPARTURE NEARLY A FULL DEGREE FROM YESTERDAY TO TODAY GIVEN THE
ROUGHLY 25 DEGREE BELOW NORMAL TEMP YESTERDAY. EVEN SMALL
VARIANCES TO FRONTAL TIMING OR THE SPECIFIC EVOLUTION OF
SHORTWAVE ENERGY EMBEDDED IN THE NORTHWEST FLOW WILL HAVE
RELATIVELY MINOR IMPACTS ON SENSIBLE WEATHER HIGHLIGHTS IN THE
LONG TERM. ANY APPRECIABLE SNOW/RAIN REMAINS WELL SOUTH/EAST OF
THE FORECAST AREA ON THE FRINGE OF THIS COLD CONTINENTAL AIR MASS.
WE EXPECT FLURRIES WITH THE CLOUD COVER ON SATURDAY MAINLY BECAUSE
WE`LL SIMPLY BE SATURATED IN THE DENDRITE GROWTH ZONE. THERE IS
VERY LITTLE LIFT. WE`LL BE QUITE BLUSTERY AT TIMES OVER THE NEXT
FEW DAYS...SO THAT COMBINED WITH CLOUD COVER BEHIND FRONTAL
PASSAGES, ETC. WILL HAVE AN IMPORTANT IMPACT ON JUST HOW COLD WE
GET - ESPECIALLY WITH OVERNIGHT LOWS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 554 AM CST FRI FEB 20 2015
BACK EDGE OF THE IFR BAND OF SNOW ALREADY WORKING INTO ERN MN THIS
MORNING. SREF PROBS FOR VIS LESS THAN 3SM HAS TRENDED WELL WITH
THE TIMING OF THE SNOW BAND ACROSS THE AREA OVERNIGHT...SO
FOLLOWED ITS TIMING FOR MOVING THE BACK EDGE ACROSS MN.
RAP/NAM/GFS ALSO SHOW ANOTHER QUICK BURST OF SNOW WORKING ACROSS
THE MN TERMINALS THIS EVENING WITH THE COLD FROPA...SO THAT IS WHY
A SECOND HINT OF SNOW SHOWS UP AT MOST MN TERMINALS THIS
AFTERNOON/EVENING. FOR WI...IT WILL LIKELY SNOW MUCH OF THE
DAY...THOUGH INTENSITY AND VSBY RESTRICTIONS WILL BE GREATEST THIS
MORNING. CIGS HAVE IMPROVED TO VFR LEVELS BEHIND THE SNOW...SO MAY
BE TO PESSIMISTIC ON MVFR CIGS REMAINING AT MSP. SREF MVFR CIG
PROBS SHOW THE MVFR CIGS WORKING EAST WITH THE SNOW...THOUGH
QUICKLY DROPPING BACK SE ACROSS THE AREA WITH THE FRONT. FOR
WINDS...STAYED CLOSE TO LAMP GUIDANCE...WHICH HAS A SIMILAR TIMING
TO THE HRRR AND NAM WITH THE FROPA.
KMSP...BEHIND THE SNOW THIS MORNING...AM CONCERNED WE WILL SEE
CIGS GO VFR FOR MUCH OF THE 15Z TO 22Z PERIOD BASED ON OBS
CURRENTLY TO THE SW. GFS/NAM/RAP/HRRR BUFR SOUNDINGS ALL SHOW
ANOTHER HIT OF -SN CENTERED AROUND 00Z AS THE FRONT COMES
THROUGH...SO JUST MOVED THE SECOND MENTION OF SNOW WE HAD BACK A
COUPLE OF HOURS. THROUGH THE NIGHT...WE SHOULD GRADUALLY SEE CIGS
WORK BACK ABOVE MVFR BY SAT MORNING. MAY ALSO SEE FLURRIES
THROUGH THE NIGHT...BUT NOT EXPECTING ANY VIS RESTRICTIONS IF WE
SEE ANY...SO LEFT ANY -SN OUT AFTER 2Z.
/OUTLOOK FOR KMSP/
SAT...VFR. WINDS NW AT 10-20KT.
SUN...VFR. WINDS NW 10-15KT.
MON...VFR. WINDS SW AT 10-15KT.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...MPG
LONG TERM...CLF
AVIATION...MPG
AREA FORECAST DISCUSSION
NWS JACKSON MS
518 AM CST FRI FEB 20 2015
.DISCUSSION...
TODAY THROUGH SATURDAY NIGHT...
COLD AND DRY AIR REMAINS LOCKED IN OVER THE ARKLAMISS THIS
MORNING WITH DEWPOINT TEMPERATURES STILL IN THE SINGLE DIGITS FOR THE
MOST PART...BUT A DEVELOPING WARM FRONT WILL MOVE NORTHEAST AND ACROSS
THE ENTIRE AREA BY SATURDAY MORNING BRINGING MUCH WARMER
TEMPERATURES. FOR NOW...THERE CONTINUES TO BE SOME CONCERN FOR LIGHT
FREEZING RAIN AS THE STRENGTHENING WARM ADVECTION ABOVE THE SHALLOW
COLD AIR CREATES A SUBSTANTIAL MID LEVEL WARM LAYER IN THE THERMAL
PROFILES. ISENTROPIC LIFT IS CAUSING WIDESPREAD STRATUS TO FORM WITH
LIGHT WINTRY PRECIP JUST NOW DEVELOPING OVER PORTIONS OF CENTRAL AR.
AM MOST CONCERNED WITH PRECIPITATION MOVING INTO THE GREENWOOD TO
COLUMBUS CORRIDOR LATER THIS MORNING GIVEN THAT IS WHERE SUB-FREEZING
SURFACE AIR WILL BE TOUGHER TO WARM. RECENT HRRR GUIDANCE SHOWS THAT
VERY LIGHT PRECIP WILL CONTINUE TO SPREAD EASTWARD FROM AR INTO NORTH
CENTRAL MS...BUT GIVEN DRY AIR IN PLACE IT APPEARS MEASURABLE PCPN
WILL LIKELY HOLD OFF UNTIL THE AFTN/EVNG. HAVING SAID THAT...LATEST
GFS BUFR SOUNDINGS INDICATE THE COLD AIR MAY HANG ON A BIT MORE THAN
ANTICIPATED SO WILL NEED TO MONITOR CLOSELY THIS TREND. WITH THAT
SAID...LATEST WPC/SREF PTYPE PROBS INDICATE THAT THE RISK FOR
MEASURABLE FZRA SHOULD MOVE NORTH OF THE AREA BEFORE 00Z.
THE FORECAST IS MORE STRAIGHT-FORWARD FROM TONIGHT INTO SATURDAY WITH
TEMPERATUERS HOLD STEADY OR RISING THROUGH THE PERIOD IN STRONG WARM
ADVECTION. INCREASING MOISTURE CONVERGENCE ALONG AN APPROACHING COLD
FRONT WILL GENERATE SHOWER ACTIVITY - AND LOCALLY HEAVY RAINFALL WILL
BECOME POSSIBLE AS A FAIRLY ROBUST MOISTURE PLUME IS DRAWN NORTHWARD
AND COMBINES WITH INCREASING INSTABILITY TO BRING TSTM POTENTIAL. IN
ADDITION...SIGNIFICANT PRESSURE FALLS WILL RESULT IN RATHER GUSTY
SOUTH WINDS AND A FEW GUSTS TO 30 MPH WILL BE LIKELY TONIGHT IN THE
DELTA REGION. GUIDANCE HAS SPED UP THE SOUTHEASTWARD-MOVING COLD
FRONT BY ROUGHLY 12 HOURS AND IT IS NOW EXPECTED TO PASS THROUGH THE
ENTIRE AREA BY EARLY SUNDAY MORNING...SO THIS WILL HELP TO LIMIT
RAINFALL TOTALS. /EC/
SUNDAY THROUGH NEXT FRIDAY...COLD AND WET CURRENTLY LOOK TO SUM UP
THE LONG TERM PORTION OF THE FORECAST...THIS GO AROUND. LIGHT RAIN
WILL LINGER BEHIND THE FRONT ON SUNDAY AS STRONG COLD ADVECTION SETS
UP ACROSS THE REGION. WITH MOISTURE ALOFT STILL RESIDING OVER THE
AREA LATE SUNDAY NIGHT INTO MONDAY MORNING AS A DISTURBANCE ALOFT
RACES EAST THROUGH THE REGION...AND VERY COLD DRY AIR UNDERCUTTING IT
AT THE SURFACE AND IN THE LOWER LEVELS OF THE ATMOSPHERE...SOME LIGHT
WINTRY PRECIPITATION COULD FALL OVER THE NORTHERN HALF OF THE CWA
EARLY MONDAY MORNING.
CLOUDS AND LIGHT RAIN AGAIN LINGER MONDAY AS ANOTHER MID/UPPER LEVEL
DISTURBANCE IS PROGGED TO RACE EAST THROUGH THE REGION.
AGAIN...WITH FREEZING TO SUB-FREEZING OVERNIGHT LOWS FORECAST OVER
MUCH OF THE REGION MONDAY NIGHT INTO TUESDAY MORNING...COUPLED WITH
MOISTURE ALOFT OVER THE REGION...SOME LIGHT WINTERY PRECIPITATION
CAN`T BE RULED OUT.
AFTER A BRIEF...BUT CONTINUED COLD...BREAK FROM PRECIPITATION ON
TUESDAY...CHANCES FOR PRECIPITATION AGAIN INCREASE WEDNESDAY.
THIS IS AS A RESULT OF AN MID/UPPER LEVEL TROUGH THAT`LL SWING EAST
ACROSS THE NATION`S MID-SECTION...CAUSING A SURFACE LOW TO DEVELOP
AND SHIFT EAST ALONG THE THE NORTHERN GULF COAST. SMALL PRECIP
CHANCES REMAIN IN THE FORECAST THURSDAY INTO FRIDAY AS ONCE AGAIN A
SERIES OF DISTURBANCES ALOFT RACE EAST THROUGH THE CWA. /19/
&&
.AVIATON...WIDESPREAD STRATUS WILL ENCOMPASS THE AREA TODAY AND
TONIGHT AS A STRONG WARM FRONT APPROACHES THE AREA. VFR CATEGORY CIGS
TODAY WILL REDUCE TO MVFR CATEGORY CIGS BY LATE TONIGHT AT MOST SITES
AS RAIN CHANCES INCREASE AS WELL. /EC/
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 53 51 67 48 / 21 56 66 84
MERIDIAN 48 45 65 51 / 13 47 49 82
VICKSBURG 58 55 70 44 / 25 73 74 85
HATTIESBURG 56 50 68 57 / 14 38 42 81
NATCHEZ 59 56 70 49 / 19 64 67 85
GREENVILLE 49 49 65 37 / 57 84 88 65
GREENWOOD 48 48 64 39 / 48 86 85 81
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
/EC/19/
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
615 AM CST FRI FEB 20 2015
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 330 AM CST FRI FEB 20 2015
PCPN CHANCES AND PCPN TYPE TONIGHT ACROSS OUR SOUTHERN COUNTIES
AND TEMPERATURES FOR ALL OF THE AREA THE NEXT FEW DAYS WILL
PROVIDE THE MAIN FORECAST CHALLENGES.
LARGE SCALE PATTERN AT 500 MB FEATURES A TROUGH FROM THE EASTERN
PACIFIC UP INTO ALASKA. TWO CLOSED LOWS WERE NOTED...ONE OVER NEW
YORK STATE AND THE OTHER OVER THE NORTHERN PART OF HUDSON BAY. OUR
AREA WAS IN NORTHWEST FLOW. 12 HOUR HEIGHT FALLS OF UP TO 60 METERS
WERE NOTED LAST EVENING FROM EASTERN WASHINGTON STATE INTO WESTERN
MONTANA. THROUGH SATURDAY THE RIDGE TO THE WEST WILL AMPLIFY A
BIT AND MOVE EAST...THEN A REX BLOCK FORMS BY SUNDAY.
TODAY WILL BE FAIRLY MILD AS THE ARCTIC AIRMASS WHICH HAS BEEN
OVER OUR AREA THE PAST COUPLE OF DAYS HAS LOOSENED ITS GRIP. WITH
WINDS GETTING MORE OF A WESTERLY COMPONENT TODAY...MOST LOCATIONS
SHOULD TOP OUT IN THE 30S AND 40S. NORTHEAST NEBRASKA APPEARS TO
HAVE THE BEST CHANCE OF SEEING MID 40S OR POSSIBLY EVEN WARMER.
EXPECT MOST OF THE AREA TO HAVE A GOOD AMOUNT OF MID AND/OR HIGH
LEVEL CLOUDS WHICH WILL DAMPEN WARMING A BIT. THERE IS SOME
QUESTION WHETHER LIGHT PCPN WILL DEVELOP OVER PARTS OF SOUTHEAST
NEBRASKA THIS AFTERNOON. LATEST HRRR AND 13 KM RAP MODELS KEEP
THINGS DRY...SO WILL TREND THAT WAY FOR NOW EVEN THOUGH SOME OTHER
MODELS DO SHOW SOME LIGHT AMOUNTS ARE POSSIBLE. THIS MAY NEED SOME
ADJUSTMENT LATER TODAY.
WINDS WILL TURN TO THE NORTH OR NORTHWEST TONIGHT AS YET ANOTHER
COLD FRONT SAGS SOUTHWARD ACROSS THE REGION. SOME FLURRIES WILL BE
POSSIBLE LATER TONIGHT AND INTO SATURDAY...ESPECIALLY NORTH. THE
MAIN PCPN WILL STAY ACROSS KANSAS AND MISSOURI...BUT HELD ONTO SOME
CHANCE POPS IN OUR SOUTHERN COUNTIES TO BLEND IN WITH NEIGHBORS TO
THE SOUTH. NAM/GFS AND ECMWF ALL HINT AT SOME MIXED PCPN. ADDED A
SLIGHT CHANCE THIS EVENING UP AS FAR NORTH AS OMAHA/COUNCIL
BLUFFS. THE PCPN TYPE COULD BE RAIN OR SNOW EARLY ON...THEN A MIX
OF RAIN/FREEZING RAIN/SNOW DEPENDING ON SURFACE TEMPERATURES. THE
00Z GFS AND 06Z NAM MODELS SEEMED JUST A BIT OVERDONE WITH QPF
ALONG THE KANSAS AND MISSOURI BORDERS TONIGHT.
TEMPERATURES SHOULD SLOWLY SLIDE DURING THE DAY SATURDAY AS COLD AIR
SETTLES SOUTH AHEAD OF A 1045 MB HIGH THAT WILL BUILD INTO SOUTHERN
SASKATCHEWAN BY SATURDAY EVENING...THEN TO THE EASTERN DAKOTAS BY
SUNDAY EVENING. EXPECT HIGHS SUNDAY TO ONLY BE IN THE TEENS. LOWS
SATURDAY NIGHT WILL BE SINGLE DIGITS...THEN MAINLY AROUND ZERO TO 5
ABOVE FOR SUNDAY NIGHT.
.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 330 AM CST FRI FEB 20 2015
TEMPERATURES WILL START TO MODERATE MONDAY...WITH HIGHS IN THE 20S.
THAT TREND SHOULD CONTINUE TUESDAY WITH HIGHS IN THE 30S...BUT A
COLD FRONT WILL PUSH THROUGH IN THE AFTERNOON. THEN BELOW NORMAL
TEMPERATURES SHOULD LAST INTO LATE WEEK.
BOTH THE 00Z GFS AND 00Z ECMWF AGREE THAT SOME LIGHT SNOW MAY
DEVELOP AS EARLY AS WEDNESDAY BUT CHANCES ARE A BIT HIGHER FOR
WEDNESDAY NIGHT...ESPECIALLY FOR OUR WESTERN COUNTIES. NOT OVERLY
CONFIDENT ON THIS AND TIMING WILL PROBABLY NEED SOME ADJUSTMENT
WITH FUTURE FORECASTS.
&&
.AVIATION...(12Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 615 AM CST FRI FEB 20 2015
VFR CONDITIONS ARE EXPECTED TO PREVAIL FOR MOST OF THE PERIOD
WITH INCREASING MID LEVEL CIGS. POTENTIAL FOR MVFR CIGS AFTER 06Z
AS MOISTURE SPREADS NORTH IN ADVANCE OF SOUTHERN PLAINS LOW AND
COLDER AIR WORKS IN FROM THE NORTH.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
SHORT TERM...MILLER
LONG TERM...MILLER
AVIATION...FOBERT
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
939 AM CST FRI FEB 20 2015
.UPDATE...
ISSUED AT 940 AM CST FRI FEB 20 2015
WE HAVE ADDED SOME FREEZING DRIZZLE TO NW MN FROM BDE-BJI...SINCE
WE HAVE GOTTEN SOME REPORTS HERE. THIS THREAT SHOULD PERSIST
THROUGH EARLY AFTERNOON UNTIL THE COLUMN COOLS SUFFICIENTLY FOR
SOME FLURRIES/LIGHT SNOW. OTHERWISE...NO OTHER CHANGES NEEDED THIS
MORNING.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 300 AM CST FRI FEB 20 2015
SNOW CHANCES TODAY AND TONIGHT WILL BE THE MAIN FORECAST
CHALLENGE...THEN WINDS TOMORROW.
NORTHWESTERLY FLOW ALOFT CONTINUES OVER THE NORTHERN PLAINS AND WV
LOOP SHOWS SEVERAL WEAK SHORTWAVES UPSTREAM. THE FIRST SHORTWAVE
CURRENTLY IS DIGGING INTO NORTHEASTERN SOUTH DAKOTA...AND THERE
HAS BEEN SOME LIGHT SNOW IN THE WARM AIR ADVECTION AHEAD OF THE
SFC LOW CURRENTLY ENTERING THE NORTHEASTERN CWA. THE LIGHT SNOW
HAS STARTED TO COME TO AN END ACROSS THE NORTHWESTERN
COUNTIES...SO THE TREND IN POPS TO PUSH HIGHEST PROBABILITIES OFF
TO THE EAST THIS MORNING SEEMS GOOD. THE RAP HAS THE NEXT WEAK
SHORTWAVES COMING THROUGH MAINLY ACROSS CENTRAL AND WESTERN
ND...WHICH FITS WITH CURRENT CANADIAN RADAR. MUCH OF THE SNOW FROM
THESE SHORTWAVES WILL REMAIN TO OUR WEST BUT CONTINUED TO KEEP
SOME LOW POPS IN OUR WESTERN COUNTIES IN CASE SOME LIGHT SNOW
CLIPS THAT AREA. WITH THE FIRST MORNING SHORTWAVE MOVING EAST AND
THE NEXT SHORTWAVES MAINLY FOCUSED ON THE FAR WESTERN TIER...THINK
THAT THERE WILL BE A PERIOD FOR THE CENTRAL CWA TODAY WHERE ONLY
LINGERING FLURRIES REMAINS. EVEN THOSE AREAS THAT GET ACCUMULATION
WILL SEE A HALF AN INCH AT MOST. THERE SHOULD BE ANOTHER LOW
CHANCE FOR ACCUMULATING SNOW AREA WIDE AS THE ARCTIC FRONT COMES
DOWN TONIGHT...BUT AGAIN IT WILL BE A DUSTING AT MOST.
TEMPS SHOULD BE FAIRLY MILD TODAY WITH GWINNER ALREADY AT 21
DEGREES AT 08Z. CONTINUED TO KEEP HIGHS IN THE TEENS IN THE NORTH
TO LOW 30S IN THE SOUTH. THE MILD TEMPS WILL END TONIGHT AS ARCTIC
AIR PLUNGES BACK SOUTH INTO THE CWA. WITH THE UPPER TROUGH DIGGING
DOWN OUT OF CANADA...ALL MODELS HAVE 850MB TEMPS BACK BELOW -20 C
FOR SATURDAY. CONTINUED TO KEEP HIGHS EITHER SIDE OF ZERO. WITH
COLD AIR ADVECTION AND A DECENT GRADIENT AHEAD OF THE ARCTIC
HIGH...NORTH WINDS COULD BECOME RATHER BREEZY SATURDAY. THE
BLOWING SNOW MODEL DOES NOT GIVE MUCH PROBABILITY DUE TO NO
FALLING SNOW AT THE TIME...BUT WILL HAVE TO WATCH WINDS ON
SATURDAY AS 925MB SPEEDS GET UP TO 25 KTS. THE WINDS WILL ALSO
KNOCK APPARENT TEMPS DOWN BELOW ADVISORY CRITERIA AT TIMES
ALTHOUGH TIMING IS STILL UNCERTAIN AT THIS POINT.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 300 AM CST FRI FEB 20 2015
SATURDAY NIGHT THROUGH SUNDAY NIGHT...CONDITIONS WILL REMAIN DRY
BUT COLD AS ARCTIC HIGH PRESSURE CONTINUES TO BUILD INTO THE AREA.
DEPENDING ON HOW MUCH WE CLEAR OUT...TEMPS SATURDAY NIGHT COULD
FALL BELOW 20 BELOW AND WITH SOME GRADIENT REMAINING...WIND CHILLS
MAY BE LOWER THEN 40 BELOW BY SUNDAY MORNING. THE SFC HIGH CENTER
BUILDING IN ON SUNDAY WILL CONTINUE WITH FRIGID TEMPS NOT RISING
INTO THE POSITIVE DIGITS. THE SFC HIGH WILL BEGIN TO SINK
SOUTHEASTWARD SUNDAY NIGHT AND WINDS WILL START PICKING UP WITH
SOME WARM AIR ADVECTION LATE IN THE NIGHT. TEMPS MAY START RISING
IN THE WEST...BUT NOT BEFORE BOTTOMING OUT IN THE TEENS BELOW
ZERO.
MONDAY THROUGH THURSDAY...THE EXTENDED BEGINS WITH A PAIR OF UPPER LEVEL
DISTURBANCES UPSTREAM IN CENTRAL CANADA. THE FIRST/WEAKER WAVE MAY
BRING A FEW FLURRIES TO THE AREA MONDAY AFTERNOON/EVENING...BUT A
BETTER CHANCE LOOKS TO COME LATER IN THE NIGHT WITH THE SECOND
WAVE. STILL...MOISTURE LOOKS LIMITED. SURFACE WINDS WILL BE
SOUTHWESTERLY ON MONDAY AHEAD OF A COLD FRONT ASSOCIATED WITH THE
SURFACE LOW PRESSURE SYSTEM. TEMPS AT 850 MB WARM CONSIDERABLY
FROM SUNDAY MORNING TO MONDAY MORNING... NEARLY 20C IN 30 HRS. THE
RESULT WILL BE HIGHS ABOUT 30 DEGREES WARMER ON MONDAY THAN ON
SUNDAY. THE COLD FRONT WILL THEN BARREL THROUGH THE AREA ON
TUESDAY MORNING. THE GOOD NEWS IS THAT IT IS EXPECTED TO BE A
GLANCING BLOW...WITH THE COLDEST AIR OFF TO THE EAST OVER FAR NE
MN AND LAKE SUPERIOR. THE BAD NEWS IS THAT STAGNANT COLD HIGH
PRESSURE WILL SET UP OVER THE NORTHERN PLANS TO END THE WEEK.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 700 AM CST FRI FEB 20 2015
MVFR CIGS CONTINUE AT MOST TAF SITES ALTHOUGH A FEW SPOTS HAVE
BRIEFLY GONE UP TO VFR. THINK THAT THIS WILL BE SHORT LIVED AND
CIGS WILL BE IN THE 1200-2500 FT RANGE FOR TODAY AND THROUGH MOST
OF TONIGHT. SOME LINGERING LIGHT SNOW AT KBJI HAS TAPERED OFF AND
MOST OF THE FORECAST POINTS SHOULD REMAIN DRY. THERE IS A CHANCE
FOR SOME SNOW LATER IN THE PERIOD AROUND KDVL...SO PUT IN SOME
MVFR VIS AND -SN FOR A BRIEF PERIOD THIS EVENING. WINDS WILL BE
SHIFTING AROUND AS LOW PRESSURE MOVES ACROSS THE AREA...WITH THE
KDVL ALREADY GOING NORTHWESTERLY THIS MORNING. THE SHIFT WILL MOVE
EASTWARD THROUGHOUT THE MORNING...WITH SPEEDS AROUND 10 TO 15 KTS.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...DK
SHORT TERM...JR
LONG TERM...JR/KNUTSVIG
AVIATION...JR
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
701 AM CST FRI FEB 20 2015
.UPDATE...
ISSUED AT 700 AM CST FRI FEB 20 2015
MADE SOME TWEAKS TO CURRENT POPS AS ONLY THE EASTERN TIER IS
CURRENTLY SEEING SNOW. THINK THAT THE EASTERN SNOW WILL MOVE
FURTHER EAST EARLY THIS MORNING AND SNOW OVER WESTERN ND MAY CLIP
OUR WESTERN CWA. SOME LINGERING BLOWING SNOW ON THE EAST SIDE OF
THE RED RIVER SHOULD DIMINISH IN THE NEXT HOUR AS THE CENTER OF
THE SFC LOW BRINGS WINDS DOWN.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 300 AM CST FRI FEB 20 2015
SNOW CHANCES TODAY AND TONIGHT WILL BE THE MAIN FORECAST
CHALLENGE...THEN WINDS TOMORROW.
NORTHWESTERLY FLOW ALOFT CONTINUES OVER THE NORTHERN PLAINS AND WV
LOOP SHOWS SEVERAL WEAK SHORTWAVES UPSTREAM. THE FIRST SHORTWAVE
CURRENTLY IS DIGGING INTO NORTHEASTERN SOUTH DAKOTA...AND THERE
HAS BEEN SOME LIGHT SNOW IN THE WARM AIR ADVECTION AHEAD OF THE
SFC LOW CURRENTLY ENTERING THE NORTHEASTERN CWA. THE LIGHT SNOW
HAS STARTED TO COME TO AN END ACROSS THE NORTHWESTERN
COUNTIES...SO THE TREND IN POPS TO PUSH HIGHEST PROBABILITIES OFF
TO THE EAST THIS MORNING SEEMS GOOD. THE RAP HAS THE NEXT WEAK
SHORTWAVES COMING THROUGH MAINLY ACROSS CENTRAL AND WESTERN
ND...WHICH FITS WITH CURRENT CANADIAN RADAR. MUCH OF THE SNOW FROM
THESE SHORTWAVES WILL REMAIN TO OUR WEST BUT CONTINUED TO KEEP
SOME LOW POPS IN OUR WESTERN COUNTIES IN CASE SOME LIGHT SNOW
CLIPS THAT AREA. WITH THE FIRST MORNING SHORTWAVE MOVING EAST AND
THE NEXT SHORTWAVES MAINLY FOCUSED ON THE FAR WESTERN TIER...THINK
THAT THERE WILL BE A PERIOD FOR THE CENTRAL CWA TODAY WHERE ONLY
LINGERING FLURRIES REMAINS. EVEN THOSE AREAS THAT GET ACCUMULATION
WILL SEE A HALF AN INCH AT MOST. THERE SHOULD BE ANOTHER LOW
CHANCE FOR ACCUMULATING SNOW AREAWIDE AS THE ARCTIC FRONT COMES
DOWN TONIGHT...BUT AGAIN IT WILL BE A DUSTING AT MOST.
TEMPS SHOULD BE FAIRLY MILD TODAY WITH GWINNER ALREADY AT 21
DEGREES AT 08Z. CONTINUED TO KEEP HIGHS IN THE TEENS IN THE NORTH
TO LOW 30S IN THE SOUTH. THE MILD TEMPS WILL END TONIGHT AS ARCTIC
AIR PLUNGES BACK SOUTH INTO THE CWA. WITH THE UPPER TROUGH DIGGING
DOWN OUT OF CANADA...ALL MODELS HAVE 850MB TEMPS BACK BELOW -20 C
FOR SATURDAY. CONTINUED TO KEEP HIGHS EITHER SIDE OF ZERO. WITH
COLD AIR ADVECTION AND A DECENT GRADIENT AHEAD OF THE ARCTIC
HIGH...NORTH WINDS COULD BECOME RATHER BREEZY SATURDAY. THE
BLOWING SNOW MODEL DOES NOT GIVE MUCH PROBABILITY DUE TO NO
FALLING SNOW AT THE TIME...BUT WILL HAVE TO WATCH WINDS ON
SATURDAY AS 925MB SPEEDS GET UP TO 25 KTS. THE WINDS WILL ALSO
KNOCK APPARENT TEMPS DOWN BELOW ADVISORY CRITERIA AT TIMES
ALTHOUGH TIMING IS STILL UNCERTAIN AT THIS POINT.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 300 AM CST FRI FEB 20 2015
SATURDAY NIGHT THROUGH SUNDAY NIGHT...CONDITIONS WILL REMAIN DRY
BUT COLD AS ARCTIC HIGH PRESSURE CONTINUES TO BUILD INTO THE AREA.
DEPENDING ON HOW MUCH WE CLEAR OUT...TEMPS SATURDAY NIGHT COULD
FALL BELOW 20 BELOW AND WITH SOME GRADIENT REMAINING...WIND CHILLS
MAY BE LOWER THEN 40 BELOW BY SUNDAY MORNING. THE SFC HIGH CENTER
BUILDING IN ON SUNDAY WILL CONTINUE WITH FRIGID TEMPS NOT RISING
INTO THE POSITIVE DIGITS. THE SFC HIGH WILL BEGIN TO SINK
SOUTHEASTWARD SUNDAY NIGHT AND WINDS WILL START PICKING UP WITH
SOME WARM AIR ADVECTION LATE IN THE NIGHT. TEMPS MAY START RISING
IN THE WEST...BUT NOT BEFORE BOTTOMING OUT IN THE TEENS BELOW
ZERO.
MONDAY THROUGH THURSDAY...THE EXTENDED BEGINS WITH A PAIR OF UPPER LEVEL
DISTURBANCES UPSTREAM IN CENTRAL CANADA. THE FIRST/WEAKER WAVE MAY
BRING A FEW FLURRIES TO THE AREA MONDAY AFTERNOON/EVENING...BUT A
BETTER CHANCE LOOKS TO COME LATER IN THE NIGHT WITH THE SECOND
WAVE. STILL...MOISTURE LOOKS LIMITED. SURFACE WINDS WILL BE
SOUTHWESTERLY ON MONDAY AHEAD OF A COLD FRONT ASSOCIATED WITH THE
SURFACE LOW PRESSURE SYSTEM. TEMPS AT 850 MB WARM CONSIDERABLY
FROM SUNDAY MORNING TO MONDAY MORNING... NEARLY 20C IN 30 HRS. THE
RESULT WILL BE HIGHS ABOUT 30 DEGREES WARMER ON MONDAY THAN ON
SUNDAY. THE COLD FRONT WILL THEN BARREL THROUGH THE AREA ON
TUESDAY MORNING. THE GOOD NEWS IS THAT IT IS EXPECTED TO BE A
GLANCING BLOW...WITH THE COLDEST AIR OFF TO THE EAST OVER FAR NE
MN AND LAKE SUPERIOR. THE BAD NEWS IS THAT STAGNANT COLD HIGH
PRESSURE WILL SET UP OVER THE NORTHERN PLANS TO END THE WEEK.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 700 AM CST FRI FEB 20 2015
MVFR CIGS CONTINUE AT MOST TAF SITES ALTHOUGH A FEW SPOTS HAVE
BRIEFLY GONE UP TO VFR. THINK THAT THIS WILL BE SHORT LIVED AND
CIGS WILL BE IN THE 1200-2500 FT RANGE FOR TODAY AND THROUGH MOST
OF TONIGHT. SOME LINGERING LIGHT SNOW AT KBJI HAS TAPERED OFF AND
MOST OF THE FORECAST POINTS SHOULD REMAIN DRY. THERE IS A CHANCE
FOR SOME SNOW LATER IN THE PERIOD AROUND KDVL...SO PUT IN SOME
MVFR VIS AND -SN FOR A BRIEF PERIOD THIS EVENING. WINDS WILL BE
SHIFTING AROUND AS LOW PRESSURE MOVES ACROSS THE AREA...WITH THE
KDVL ALREADY GOING NORTHWESTERLY THIS MORNING. THE SHIFT WILL MOVE
EASTWARD THROUGHOUT THE MORNING...WITH SPEEDS AROUND 10 TO 15 KTS.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...JR
SHORT TERM...JR
LONG TERM...JR/KNUTSVIG
AVIATION...JR
AREA FORECAST DISCUSSION...UPDATED
NWS NORMAN OK
542 AM CST FRI FEB 20 2015
.AVIATION...
STRATUS CONTINUES TO SPREAD NORTH AND WEST MOVING INTO KOUN..
KOKC.. KPNC AND KLAW VERY SOON. WENT PRIMARILY WITH THE HRRR MODEL
ON HOW FAR WEST TO BRING THE STRATUS /VERY NEAR KHBR.. KCSM AND
KSPS AND NOT INTO KGAG AND KWWR/... BUT WILL BE WATCHING TRENDS.
THE TIMING OF THE STRATUS MOVING OUT OF THE AREA IS STILL VERY
MUCH IN QUESTION. HAVE BEEN LESS AGGRESSIVE WITH FOG DEVELOPMENT
GIVEN THE TIMING OF THE STRONGER SURFACE MOISTURE ADVECTION. A
COLD FRONT WILL MOVE THROUGH THE AREA THIS EVENING BRINGING A
BRISK NORTH WIND. GFS WOULD SUGGEST THAT THESE NORTH WINDS COULD
BE STRONGER THIS EVENING AND OVERNIGHT BEHIND THE COLD FRONT.
&&
.PREV DISCUSSION... /ISSUED 401 AM CST FRI FEB 20 2015/
DISCUSSION...
IT IS A COMPLEX WEATHER FORECAST THIS MORNING. MOISTURE ADVECTION
CONTINUES FROM THE SOUTHEAST THIS MORNING AND WITH THIS WILL BE A
CHANCE OF FOG/DRIZZLE THIS MORNING AND AT LEAST SOME LOW CHANCES
OF RAIN IN THE SOUTHEAST. TEMPERATURES WILL BE WARMER... ALTHOUGH
THE POTENTIAL ACROSS THE EASTERN HALF OF THE AREA WILL BE
MODERATED BY CLOUD COVER. DOWNSLOPE COMPONENT AND VERY WARM
TEMPERATURES IN THE LOW-LEVELS OF THE ATMOSPHERE WILL MAKE IT
QUITE WARM IN OUR TEXAS COUNTIES TODAY. COLD FRONT SWEEPS ACROSS
THE AREA TONIGHT WITH PRECIPITATION CHANCES CONTINUING... MAINLY
ACROSS THE EAST AND NORTH. SOME ELEVATED INSTABILITY DEVELOPS
GIVING A CHANCE OF THUNDERSTORMS OVERNIGHT ACROSS SOUTHERN AND
EASTERN OKLAHOMA. TEMPERATURES TOMORROW WILL STILL BE SEASONABLE
DESPITE THE FRONT OVERNIGHT.
A REINFORCING SHOT OF COLD AIR MOVES INTO THE AREA ON SUNDAY AND
REMINDS US THAT IT IS STILL WINTER. PRECIPITATION CHANCES PERSIST
INTO MONDAY WITH ENOUGH COLD AIR MOVING INTO THE AREA TO SUPPORT
WINTER PRECIPITATION. PRECIPITATION AMOUNTS MAY NOT BE TOO HIGH...
BUT WITH WINTER PRECIPITATION CHANCES SUNDAY AND MONDAY... MAY
HAVE SOME AREAS SLOWLY ACCUMULATE A COUPLE OF INCHES OF SNOW.
THERE IS ALSO SOME QUESTION IN THE MODELS ABOUT SUFFICIENT
HUMIDITY IN THE ICE CRYSTAL GROWTH LAYER AT TIMES TO KEEP FREEZING
RAIN IN THE DISCUSSION. RIGHT NOW WILL CONTINUE TO GO MOSTLY WITH
SNOW ALTHOUGH I HAVE MENTIONED FREEZING RAIN IN SOME AREAS ON
MONDAY. WILL CONTINUE TO WATCH TRENDS AS THIS DEVELOPS.
MOVING INTO MID-WEEK... FORECAST CONFIDENCE REMAINS LOW AS MEDIUM
RANGE MODELS DIFFER IN THE LOCATIONS OF THE LONGWAVE TROUGH IN THE
WEST AND THE WEAK RIDGE AHEAD OF IT SOMEWHERE IN THE ROCKIES OR
THE PLAINS. HOWEVER THERE IS REASONABLE AGREEMENT LATER IN THE
WEEK /JUST BEYOND THIS FORECAST PERIOD/ OF THE POTENTIAL OF MUCH
COLDER AIR SLIDING DOWN THE PLAINS.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 57 40 54 25 / 20 20 10 20
HOBART OK 63 39 54 27 / 10 0 0 10
WICHITA FALLS TX 73 46 59 31 / 10 0 0 10
GAGE OK 61 33 48 20 / 0 10 10 50
PONCA CITY OK 47 35 50 21 / 30 40 10 20
DURANT OK 61 51 61 32 / 40 30 20 10
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
99/99/01
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
601 AM CST FRI FEB 20 2015
.UPDATE...
AVIATION DISCUSSION UPDATED BELOW.
&&
.SHORT TERM...TODAY THROUGH SUNDAY
AS OF 9Z...A SURFACE LOW PRESSURE SYSTEM IS LOCATED OVER NORTHERN
NORTH DAKOTA. THE WARM FRONT ASSOCIATED WITH THE LOW PRESSURE IS
ALONG THE MISSOURI RIVER. THE WARM FRONT WILL PUSH EAST TODAY
ALLOWING FOR ABOVE NORMAL TEMPERATURES TO SPREAD ACROSS THE CWA.
THE PAST FEW RUNS OF THE HRRR AND RAPID REFRESH...PLUS THE NSSL
WRF ALL SUPPORT HIGHS IN THE MID 40S TO THE MID 50S FOR NORTH
CENTRAL AND CENTRAL SOUTH DAKOTA. COOLER TEMPERATURES ARE EXPECTED
IN NORTHEASTERN SOUTH DAKOTA AND WESTERN MINNESOTA.
A COLD FRONT...CURRENTLY OVER SOUTHERN CANADA...WILL SLIDE
SOUTHWARD ACROSS THE CWA LATER THIS AFTERNOON. LIGHT PRECIPITATION
IS POSSIBLE ALONG THIS FRONT...HOWEVER CHANCES APPEARS BETTER POST
FRONTAL...OR WITH THE CAA. PRECIPITATION AMOUNTS SHOULD BE RATHER
LIGHT. COLD AIR ADVECTION...THANKS TO AN ARCTIC HIGH
PRESSURE...WILL CONTINUE THROUGH SUNDAY WITH TEMPERATURES BECOMING
PROGRESSIVELY COLDER. HIGHS ON SATURDAY WILL RANGE FROM THE SINGLE
DIGITS...TO THE MID 20S. HIGHS BY SUNDAY WILL LIKELY RANGE FROM
THE SINGLE DIGITS BELOW ZERO...IN NORTHEASTERN SOUTH DAKOTA...TO
THE MID TEENS IN CENTRAL SOUTH DAKOTA.
.LONG TERM...SUNDAY NIGHT THROUGH THURSDAY
VERY GOOD AGREEMENT WITH ALL OF THE MODELS IN THE LONG TERM. THE
PERIOD BEGINS WITH ARCTIC HIGH PRESSURE CENTERED OVER EASTERN SD
BUILDING SOUTHEAST THROUGH SUNDAY NIGHT. AFTER A COLD SUNDAY
NIGHT...SOUTHWEST WINDS ON THE BACKSIDE OF THIS SURFACE HIGH WILL
BRING IN WARMER AIR WITH TEMPERATURES WARMING UP TO NEAR NORMAL BY
LATE MONDAY AFTERNOON. MONDAY NIGHT WILL BE MILD WITH PACIFIC AIR
MOVING ACROSS THE REGION ON WEST WINDS. TUESDAY WILL REMAIN NEAR
NORMAL FOR HIGHS WITH A TROUGH COMING THROUGH AS WINDS TURN
NORTHWEST AND INCREASE. AN ARCTIC BOUNDARY WILL THEN PUSH THROUGH
LATE TUESDAY AFTERNOON AND EVENING. ARCTIC AIR WILL REMAIN OVER
THE REGION THROUGH THURSDAY WITH MUCH BELOW NORMAL TEMPERATURES.
THE MODELS ALL SHOW A CLIPPER SYSTEM DROPPING SOUTHEAST ALONG THE
ARCTIC BOUNDARY LATE TUESDAY NIGHT THROUGH WEDNESDAY NIGHT. AT
THIS TIME THEY ALL SHOW SOME SNOW WITH THIS SYSTEM MAINLY ACROSS
THE WESTERN CWA. THUS...INCREASED POPS SOME AND MAY HAVE TO
INCREASE THEM MORE IN LATER FORECASTS.
&&
.AVIATION...
12Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
MVFR/LOW VFR STRATUS CLOUDS ARE EXPECTED OVER ALL TAF LOCATIONS
THROUGH THE DAY AS LOW LEVEL RH REMAINS HIGH IN THE MIXING LAYER.
AS NORTHWEST WINDS COME AROUND TO THE NORTH AND NORTHEAST TONIGHT
...EXPECT CEILINGS TO FALL TO LOW MVFR/IFR AT ALL LOCATIONS REMAINING
THROUGH THE REST OF THE PERIOD. WILL ALSO HAVE TO WATCH FOR SOME
LIGHT SNOW SHOWERS MAINLY FOR TONIGHT.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
UPDATE...MOHR
SHORT TERM...SD
LONG TERM...MOHR
AVIATION...MOHR
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
408 AM CST FRI FEB 20 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 408 AM CST FRI FEB 20 2015
SNOWFALL WHICH HAS BEEN SCARCE SO FAR OVERNIGHT WILL GET ONE LAST
CHANCE THROUGH THE REMAINDER OF THE OVERNIGHT AS UPPER WAVE SHEARS
SOUTHEAST FROM NORTHEAST SOUTH DAKOTA INTO SOUTHERN MINNESOTA. WHILE
MARKEDLY BETTER CHANCE JUST NORTHEAST OF THE CWA...HAVE INCLUDED
SMALLER CHANCE POPS FOR THE REST OF THE OVERNIGHT TO COVER TIMING OF
WAVE. FOLLOWING THIS WAVE...OTHER THAN THE INCREASINGLY SHALLOW
LOWER LEVEL WARM ADVECTION...PRETTY MUCH SET UP FOR A PERIOD OF
FAIRLY LACKLUSTER FORCING BEHIND THIS WAVE THROUGH THE AFTERNOON...
WITH THE EVENTUAL NORTH-SOUTH SPLIT TO UPSTREAM SYSTEM PUSHING A
FRONTAL BOUNDARY INTO THE NORTHERN CWA DURING THE LATER AFTERNOON.
SEVERAL MODELS INDICATE THAT THERE WILL BE SOME LIGHT QPF NEAR THIS
BOUNDARY DURING THE LATER AFTERNOON...BUT MUCH OF THIS LOOKS TO BE A
RESULT OF SURFACE BASED DESTABILIZATION RATHER THAN ANY DYNAMICAL
LIFT FORCING WHICH REMAINS MINIMAL THROUGH THE DAY.
IT WILL BE SIGNIFICANTLY WARMER TODAY ACROSS THE AREA...WITH THE
GREATEST CHALLENGE TO THIS WARMING TO BE THE EXTENT OF CLOUDINESS
GIVEN A RELATIVE LACK OF SNOW COVER. BEHIND THE EARLY MORNING UPPER
WAVE...EXPECT MORE WIDESPREAD LOWER CLOUDINESS ACROSS CENTRAL NORTH
DAKOTA TO CONTINUE TO SURGE SOUTHEASTWARD...AS IS CURRENTLY UNDERWAY
IN NORTH CENTRAL SD. RAP SEEMS TO HAVE AN ADEQUATE HANDLE ON THE
SHORT TERM BEHAVIOR OF THE CLOUD FIELDS...AND HAVE GENERALLY USED AS
A GUIDE TO TRANSLATE THE LOWER CLOUDS SOUTH AND EAST THROUGH THE
DAY...HOLDING TOUGH MUCH OF THE DAY ACROSS SW MN AND INTO PARTS OF
NW IA. GIVEN TEMPS IN THE UPPER 20S TO AROUND 30 UNDER THE INCREASED
CLOUDS...AM HESITANT TO GO QUITE AS COOL AS SEVERAL SOLUTIONS
SUGGEST...AND HAVE BASED OFF A MODIFIED RAP SURFACE THERMAL FIELD
THROUGH THE DAY. THERE WILL AT LEAST BE A FAIR AMOUNT OF HIGHER
CLOUDS AROUND IN OTHER AREAS SOUTHWEST OF THE LOWER CLOUDS...WHERE
WHICH IT WILL LIKELY PUSH 50 DEGREES ON MIXING ALONE IN THE WESTERN
MISSOURI VALLEY...AND EVEN A MODEST RIDE INTO THE LOWER 30S EXPECTED
IN SW MN.
LOWER LEVEL COLD AIR WILL BEGIN TO SURGE SOUTHWARD...ESPECIALLY
THROUGH THE LATTER HALF OF THE NIGHT...WITH FAIRLY STRONG
ISALLOBARIC RISES SET TO DRIVE AN INCREASING NORTHERLY WIND THROUGH
THE NIGHT. THIS TYPE OF SET UP ALMOST ALWAYS HAS THE COOLING COMING
IN A MORE FORCEFUL WAY...AND HAVE PUSHED THE COOLING RATES UP ABOUT
3 HOURS LATER TONIGHT AND EARLY SATURDAY MORNING THAN EVEN SOME OF
THE COOLER RAW GUIDANCE. GRADUALLY...THERMAL FIELDS BECOME MORE
FAVORABLE FOR SHALLOW FORCED PRECIPITATION BEHIND THE FRONTAL
BOUNDARY. AT THIS TIME...HAVE PRECLUDED ANY MENTION OF MEASURABLE
SNOWFALL /OR POTENTIALLY RAINFALL EARLY EVENING IN THE WEST/...BUT
DID WORK IN A GRADUAL NORTH TO SOUTH SPREAD FOR ISOLATED TO
SCATTERED FLURRIES. WIND CHILLS BY MORNING WILL RETURN BELOW ZERO
FROM EAST CENTRAL SD THROUGH MUCH OF SW MN.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 408 AM CST FRI FEB 20 2015
FOR THE WEEKEND...THE FORECAST CONCERN CENTERS ON THE ARCTIC AIR
MOVING IN. THE COLD AIR BEHIND THE FRONT THAT MOVES THROUGH
TONIGHT WILL CONTINUE TO SURGE SOUTHWARD ON SATURDAY. AS A RESULT
EXPECT TEMPERATURES TO BASICALLY BE STEADY OR SLOWLY FALL THROUGH
THE DAY WITH HIGHS LIKELY TO BE AROUND SUNRISE. BY EVENING
TEMPERATURES WILL RANGE FROM THE SINGLE DIGITS ABOVE ZERO NORTH OF
I90 TO THE LOWER 20S IN THE MISSOURI VALLEY. NORTHWEST WINDS WILL
BE GUSTING AS HIGH AS 30 MPH BEHIND THE FRONT AND THIS WILL
PRODUCE WIND CHILLS BELOW ZERO NORTH OF AND EAST OF THE JAMES AND
MISSOURI VALLEY THROUGHOUT THE DAY.
NORTHWEST WINDS ARE EXPECTED TO REMAIN BETWEEN 10 AND 20 MPH
SATURDAY NIGHT AND MUCH OF SUNDAY. WITH LOWS EXPECTED TO BE AT OR
BELOW ZERO IN ALL BUT THE MISSOURI VALLEY SATURDAY NIGHT...WIND
CHILLS WILL RANGE FROM -15 TO -30 LATE SATURDAY NIGHT AND SUNDAY
MORNING WITH THE COLDEST WIND CHILLS IN SOUTHWEST MINNESOTA.
DESPITE SUNSHINE AND LITTLE SNOW COVER...HIGHS SUNDAY WILL
GENERALLY BE IN THE SINGLE DIGITS ABOVE ZERO. HIGH PRESSURE WILL
MOVE FROM MINNESOTA INTO WESTERN ILLINOIS ON SOUNDAY NIGHT. WINDS
WILL DECREASE FAIRLY RAPIDLY AFTER DARK AND THEN AS THE HIGH MOVES
THROUGH IOWA...TURN TO THE SOUTH AND BEGIN TO INCREASE...ESPECIALLY
WEST OF I29. WITH CLEAR SKIES AND LIGHT WINDS...MOST LOCATIONS
WILL FALL IN THE EVENING BUT TEMPERATURES WILL BECOME STEADY OR
EVEN RISE A FEW DEGREES AFTER MIDNIGHT. AS A RESULT...LOWS WILL
BE IN THE SINGLE DIGITS BELOW ZERO EAST OF THE JAMES RIVER AND IN
THE SINGLE DIGITS ABOVE ZERO WEST OF THE JAMES RIVER.
IN THE EXTENDED...MONDAY THROUGH THURSDAY...IT WILL BE A CONTRAST
IN REGIMES...WITH NEAR NORMAL TO ABOVE NORMAL TEMPERATURES MONDAY
AND TUESDAY AND BELOW NORMAL TEMPERATURES WEDNESDAY AND THURSDAY
AS ANOTHER SURGE OF ARCTIC AIR MOVES INTO THE AREA. THERE IS
SURPRISINGLY LITTLE DIFFERENCE IN THE OVERALL PATTERN BETWEEN THE
ECMWF...GFS AND THE GFS ENSEMBLE. SO CONFIDENCE IS HIGH IN TERMS
OF THE TEMPERATURE TRENDS. THE ONLY UNCERTAINTY RESTS WITH THE
CHANCE OF SNOW ON WEDNESDAY AND WEDNESDAY NIGHT. THE ECMWF IS
WEAKER WITH THE SNOWFALL...BASICALLY EXTENDING FROM WESTERN NORTH
DAKOTA...THROUGH MUCH OF SOUTH DAKOTA...AND INTO EASTERN NEBRASKA
AND FAR WESTERN IOWA. THE GFS IS GENERALLY IN THE SAME AREA BUT
FASTER AND WITH MORE SNOWFALL. WITH AN ARCTIC AIR MASS IN
PLACES...MOISTURE WILL BE LIMITED SO A SOLUTION CLOSER TO THE
ECMWF SEEMS MORE LIKELY AT THIS POINT.
ON MONDAY WILL SEE A GRADUAL WARMING AS WINDS INCREASE OUT OF THE
SOUTHWEST. BY AFTERNOON IT COULD BECOME QUITE BREEZY AND WITH
SKIES EXPECTED TO BE PARTLY TO MOSTLY SUNNY...THE ATMOSPHERE
SHOULD BECOME MORE MIXED THROUGH THE DAY. AS A RESULT...EXPECT TO
SEE QUITE A DIURNAL RANGE WITH HIGHS WARMING 25 TO 30 DEGREES INTO
THE MID 20S TO MID 30S. WITH WEST TO NORTHWEST FLOW CONTINUING
MONDAY NIGHT...EXPECT TEMPERATURES TO REMAIN IN THE 20S. TUESDAY
WILL SEE THE PASSAGE OF THE NEXT ARCTIC FRONT. WITH STRONG
NORTHWEST WINDS BEHIND THE FRONT...EXPECT THE AIR ALOFT TO MIX TO
THE SURFACE HELPING TEMPERATURES TO RISE BACK ABOVE FREEZING
BEFORE THE REAL COLD AIR MOVES BACK IN TUESDAY NIGHT. HIGHS
WEDNESDAY WILL BE IN THE TEENS AND 20S WITH EVEN COLDER
TEMPERATURES EXPECTED THURSDAY. WITH THE COLD AIR IN CANADA WOULD
NOT BE SURPRISED IF THIS AIR MASS ENDS UP A FEW DEGREES COLDER
THAN FORECAST BUT WILL WAIT UNTIL THERE IS MORE CONFIDENCE IN THE
MAGNITUDE OF THE COLD AIR BEFORE LOWERING TEMPERATURES EVEN MORE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY EVENING)
ISSUED AT 1040 PM CST THU FEB 19 2015
MAINLY EXPECTING VFR CONDITIONS THROUGH THE NIGHT AT TAF SITES.
LIGHT SNOW AND FLURRIES STILL HAVING A TOUGH TIME REACHING THE
GROUND...BUT STILL MAY GET A BRIEF PERIOD OF MVFR VIS EAST OF
INTERSTATE 29 IN LIGHT SNOW. OTHERWISE SIGNS THAT LOWER MVFR STRATUS
CURRENTLY OVER NORTH DAKOTA AND CANADA WILL TRY TO WORK SOUTH BEHIND
THE COLD FRONT AFTER 12Z FRIDAY. STILL QUITE A BIT OF UNCERTAINTY ON
HEIGHT AND COVERAGE OF THIS STRATUS...BUT ENOUGH CONFIDENCE THAT
DECIDED TO INTRODUCE A PERIOD OF MVFR CIGS AT KHON AND KFSD FRIDAY
MORNING. EXPECT THIS SHOULD INCREASE BACK TO VFR BY AFTERNOON AT THE
TAF SITES...ALTHOUGH LOWER CIGS COULD LINGER OVER SOUTHWEST
MINNESOTA. WILL NEED TO CONTINUE TO MONITOR TRENDS IN THE
OBSERVATIONS AND FUTURE MODEL RUNS. SECONDARY COLD FRONT MOVING
THROUGH FRIDAY EVENING MAY BRING A RETURN TO THE MVFR CIGS.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
SHORT TERM...CHAPMAN
LONG TERM...SCHUMACHER
AVIATION...CHENARD
FOR FREQUENTLY ASKED QUESTIONS ABOUT THE AREA FORECAST DISCUSSION
VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY/GENERAL/AFD_FAQS.PHP (ALL LOWER CASE)
AREA FORECAST DISCUSSION
NWS GOODLAND KS
223 PM MST FRI FEB 20 2015
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 220 PM MST FRI FEB 20 2015
VISIBLE SATELLITE IMAGERY WAS INDICATING PARTLY TO MOSTLY CLOUDY
SKIES OVER THE TRI STATE AREA IN THE EARLY AFTERNOON...WITH RADAR
INDICATING SOME LIGHT PRECIPITATION BEGINNING TO OCCUR IN CENTRAL
NEBRASKA AND EASTERN COLORADO AHEAD OF AN UPPER LEVEL SHORTWAVE
TROUGH. WATER VAPOR IMAGERY SHOWED A STEADY STREAM OF MOISTURE THAT
WILL MOVE INTO THE FORECAST AREA TONIGHT...WHICH WILL BRING OVERCAST
SKIES AND CHANCES FOR PRECIPITATION.
HRRR AND RAP FORECASTS SHOW LIGHT RAIN SHOWERS BEGINNING TO AFFECT
EASTERN COLORADO BETWEEN THE 21Z AND 00Z TIME PERIOD TONIGHT...AND
THEN GRADUALLY SPREADING IN COVERAGE OVER NORTHWEST KANSAS. RAIN
WILL TRANSITION TO A RAIN/SNOW MIX AROUND 3Z...AND THEN TURN TO ALL
SNOW AFTER 6Z. PRECIPITATION AREA WILL ENTER A DRY PERIOD SHORTLY
AFTER 6Z AND LAST THROUGH 18Z SATURDAY WHERE VERY LIGHT SNOW
ACCUMULATIONS WILL OCCUR...IF ANY. MODEL GUIDANCE WAS SHOWING
ANYWHERE FROM A HALF INCH UP TO 2 INCHES FOR EASTERN COLORADO
ACCUMULATING DURING THE DAY SATURDAY. THE HIGHER GUIDANCES SEEMED TO
BE ACCUMULATING SNOW BEFORE THE 850 FREEZING LINE PASSED THROUGH AND
THE 1540 LINE FOR THE 850-700 MB THICKNESS...WHICH LED TO THE
DECISION TO BRING SNOW AMOUNTS UNDER HALF AN INCH DURING THE DAY
SATURDAY.
RAIN AND RAIN/SNOW MIXES WILL OCCUR SOUTH OF A LINE FROM CHEYENNE
WELLS COLORADO TO TRENTON NEBRASKA SATURDAY AFTERNOON...WITH SNOW
NORTH OF THIS LINE. ABOUT ANOTHER HALF OF AN INCH WILL ACCUMULATE
FOR EASTERN COLORADO BEFORE 00Z SUNDAY WHERE THE PRECIPITATION WILL
ALL CHANGE OVER TO SNOW...WHICH WILL BRING THE GREATER SNOW
ACCUMULATIONS HEADING INTO SATURDAY NIGHT. WITH A LACK OF LOWER AND
MID LEVEL JET WINDS IN COMBINATION WITH A 8 MB SURFACE PRESSURE
GRADIENT...WINDS ARE NOT EXPECTED TO GUST ABOVE 25 MPH DURING THIS
PERIOD. THEREFORE...BLOWING SNOW WILL NOT BE AN ISSUE.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 220 PM MST FRI FEB 20 2015
UPPER FLOW WILL BE WESTERLY ACROSS THE CENTRAL PLAINS SATURDAY NIGHT
AS THE BROAD TROUGH ELONGATES FROM THE WEST COAST TO THE GREAT
LAKES. AS THE TROUGH CONTINUES TO SPLIT ON SUNDAY A RIDGE WILL
START AMPLIFYING OVER THE CENTRAL PLAINS. THE RIDGING CONTINUES
OVER THE CENTRAL PLAINS MONDAY WITH A LOW OVER THE DESERT SOUTHWEST
AND THE OTHER PORTION OF THE TROUGH NORTHEAST OF THE GREAT LAKES.
THE MODELS CONTINUE TO SHOW SPLIT FLOW SUNDAY/SUNDAY NIGHT WITH
RIDGING OVER THE FA MONDAY. EXPERIENCE WITH THIS PATTERN IS NOT
FAVORABLE FOR PRECIPITATION ACROSS THE FA. GOOD DYNAMICS ARE
INDICATED FOR SATURDAY NIGHT AS A SHORTWAVE COMES THROUGH THE FLOW.
HOWEVER, IT IS DIFFICULT TO JUSTIFY THE LARGE AMOUNTS OF SNOWFALL
THE GFS AND NAM ARE PRODUCING FOR THAT 12 HOUR TIME PERIOD WHICH
EQUATES TO ABOUT AN INCH PER HOUR FOR THE ENTIRE 12 HOUR PERIOD.
PLAN TO GO SOMEWHERE UNDER THOSE AMOUNTS TO OBTAIN A MORE REASONABLE
HOURLY SNOWFALL RATE. AT THIS TIME TOTAL SNOWFALL AMOUNTS SHOULD
RANGE FROM 2 INCHES NEAR HILL CITY AND MCCOOK TO 5 TO 9 INCHES IN AN
AREA SOUTHWEST OF A LINE FROM YUMA COLORADO TO LEOTI KANSAS. THESE
AMOUNTS INCLUDE UP TO 3 INCHES FROM SUNDAY THROUGH MONDAY WHICH MAY
TURN OUT TO BE LESS THAN THAT IF THE RIDGING MENTIONED ABOVE LIMITS
THE SNOWFALL. WIND SPEEDS WILL RANGE FROM 15 TO 25 MPH SATURDAY
NIGHT WITH SPEEDS DECREASING SUNDAY/SUNDAY NIGHT.
A WINTER STORM WARNING AND WINTER WEATHER ADVISORY HAS BEEN POSTED
FOR SATURDAY EVENING THROUGH SUNDAY EVENING. (SEE DETAILS BELOW).
MIN TEMPERATURES SATURDAY NIGHT SHOULD BE IN THE TEENS. COLDER MIN
TEMPERATURES IN THE SINGLE DIGITS ABOVE ZERO AND LOW TEENS ARE
EXPECTED SUNDAY NIGHT. MAX TEMPERATURES WILL BE IN THE TEENS SUNDAY
AND AROUND 20 ON MONDAY.
IN THE EXTENDED...(MONDAY NIGHT THROUGH FRIDAY)...THE FORECAST WILL
BE DRY MONDAY NIGHT AND TUESDAY WITH LACK ANY DYNAMICS UNDER
WESTERLY FLOW. THE PART OF THE TROUGH THAT SPLITS OFF OVER THE WEST
COAST WILL MOVE INTO THE DESERT SOUTHWEST TUESDAY AND ACROSS THE
CENTRAL/SOUTHERN PLAINS WEDNESDAY. THERE WILL BE A CHANCE TO SLIGHT
CHANCE OF LIGHT SNOW AS THIS TROUGH MOVES EAST THROUGH FRIDAY.
MIN TEMPERATURES MONDAY NIGHT THROUGH WEDNESDAY NIGHT WILL BE IN THE
TEENS. MIN TEMPERATURES THURSDAY NIGHT WILL BE IN THE SINGLE DIGITS
ABOVE ZERO. MAX TEMPERATURES TUESDAY AND WEDNESDAY SHOULD RANGE FROM
THE MID 30S TO 40. MAX TEMPERATURES THURSDAY AND FRIDAY WILL BE IN
THE 20S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1034 AM MST FRI FEB 20 2015
VFR CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD FOR BOTH
TERMINALS. BROKEN AND OVERCAST SKIES WILL BE PRESENT THROUGHOUT
THE ENTIRE PERIOD FOR BOTH TERMINALS WITH SOME LIGHT PRECIP
AFFECTING KGLD...WHICH WILL START AS RAIN AND TRANSITION TO SNOW
AFTER 6Z. RAIN/SNOW SHOWERS ARE EXPECTED AROUND MCCOOK...BUT
CONFIDENCE IS NOT HIGH ENOUGH YET TO INCLUDE DIRECT MENTION IN THE
TAF.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...WINTER WEATHER ADVISORY FROM 6 PM SATURDAY TO MIDNIGHT CST
SUNDAY NIGHT FOR KSZ001-002-014-015-028-029.
WINTER STORM WARNING FROM 5 PM MST /6 PM CST/ SATURDAY TO 11 PM
MST /MIDNIGHT CST/ SUNDAY FOR KSZ013-027-041-042.
CO...WINTER STORM WARNING FROM 5 PM SATURDAY TO 11 PM MST SUNDAY FOR
COZ090>092.
NE...WINTER WEATHER ADVISORY FROM 5 PM MST /6 PM CST/ SATURDAY TO 11
PM MST /MIDNIGHT CST/ SUNDAY FOR NEZ079-080.
&&
$$
SHORT TERM...MK
LONG TERM...FS
AVIATION...MK
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1123 AM CST Fri Feb 20 2015
...AVIATION UPDATE...
.UPDATE...
Issued at 1030 AM CST FRI FEB 20 2015
12Z models data coming in and continue to show potential for mixed
precip this evening and overnight. Main uncertainty remains the
low level temp profile this evening and overnight with models all
within 1 to 2 C of freezing. The NAM is the colder solution which
would favor more snow. On the other hand the RAP tends to keep
surface temps above freezing and precip mainly rain through at
least 07Z. So with forecasts all within the margin of error, it
is difficult to predict the type of precip with much confidence
and would expect some combination of rain, freezing rain and snow
overnight.
As for accumulations the good news is with a weaker more
progressive system, models are not generating much moisture in
general with QPF amounts ranging from a couple hundredths over
north central KS to possibly a quarter of an inch over far
eastern KS. So worst case scenarios for accumulations would be 2 to
3 inches of snow or perhaps up to a quarter inch of ice
accumulation. Because the forecast anticipates mixed precip such
that precip is not all snow nor is it all ice, snow accumulations
are forecast be less than an inch and ice accumulations around a
tenth of an inch. This will probably be variable across northeast
and east central KS based on temps, but snow is more likely north
of I-70 and rain/freezing rain is more likely south of I-70. The
forecast anticipates the greatest impact to be west of a line from
Council Grove to Marysville.
Precip is still on track to come to an end before 8 AM Saturday
so the timing for the greatest impact remains during the evening
and overnight hours. Precip is expected to begin spreading north
across the area late this afternoon with temps above freezing. It
is between 7 PM and 10 PM when temps may fall to the freezing mark
and hazards start to be realized.
&&
.SHORT TERM...(Today and Tonight)
Issued at 248 AM CST FRI FEB 20 2015
The forecast for the short term remains quite challenging as we
continue to monitor the potential for a wintry mix of precipitation
tonight into Saturday morning.
At the surface, high pressure prevailed over the eastern U.S. with
low pressure situated over the Rockies, resulting in light
southeasterly winds, mostly clear to partly cloudy skies, and
temperatures early this morning plunging into the teens. Satellite
imagery showed a swath of low clouds stretching across Arkansas and
eastern Oklahoma as southerly flow in that region continued to
advect moisture northward. How quickly this cloud cover lifts into
the region and how expansive the cloud cover becomes will have a
significant impact on temperatures today. Current forecast has highs
reaching into the mid 30s to mid 40s from east to west, however if
the region quickly becomes blanketed by cloud cover then
temperatures may only reach into low to upper 30s. Model soundings
show increasing low level moisture in east central Kansas by mid to
late morning and continuing through this afternoon, so expect some
patchy freezing drizzle initially before warming up enough for
drizzle or even light rain this afternoon for locations generally
along and south of I-35. Moisture advection will strengthen by this
evening with light precipitation overspreading the region from south
to north. An advancing mid-level trough will help to push a cold
front through the region tonight into the early overnight hours, and
moisture associated with this boundary is expected to converge with
the southern stream moisture by mid to late evening. The last couple
of model runs have trended toward a faster departure of
precipitation from west to east so have decreased POPs across north
central Kansas during the overnight hours. The precipitation type
forecast continues to be quite challenging for tonight as it will be
very dependent upon how much we warm up today and at what rate
temperatures cool to near and below freezing tonight. As a result,
confidence in the precipitation type and QPF forecasts is
unfortunately still low. In general, focus has shifted more toward
concerns for ice accumulations with lesser snow accumulations than
previously expected. Expect areas of rain to gradually transition
to a wintry mix of freezing rain, sleet, and snow across most
locations. Locations along and south of I-35 should see predominantly
rain, freezing rain, and sleet, while locations north of I-35 should
see more of a mix of freezing rain, sleet, and snow. At this time,
snow accumulations look to be around one-half inch or less. Ice
accumulations upwards of around one tenth of an inch are possible
along and south of I-35 with lesser amounts to the north. With these
concerns for ice accumulations and the associated hazardous travel
conditions, a Winter Weather Advisory has been issued for counties
in far northeast and east central Kansas from 6pm tonight through
9am Saturday.
.LONG TERM...(Saturday through Thursday)
Issued at 248 AM CST FRI FEB 20 2015
Saturday morning may have a bit of lingering precipitation, but
should dry out quickly after sunrise (if not earlier). If any
precip does linger, temperatures are likely to be very near the
freezing mark with slightly warmer temperatures aloft so have a
mix of precip types possible. There also seems to be some
potential for flurries behind the main precip area and
particularly in north central KS so have included a mention of
that in the forecast for early Saturday as well. Otherwise, the
remainder of Saturday through Monday is dominated by strong
surface high pressure. This low level airmass will also be quite
dry and quite cold. The dry air will impact the forecast markedly
as there is persistent weak vertical motion aloft in central KS
through this period, but will likely result in little more than
virga over the local forecast area. Will need to monitor the
situation as minor changes in the forecast could result in a
persistent but light snow on the western and southern edges of the
forecast area...but this appears to be quite unlikely at this
time. Sunday looks to be the coldest day of the period as the high
pressure settles directly overhead. Clouds will keep daytime temps
cool, and if any clearing takes place Sunday night, the current
single digit forecast may be too warm.
By late in the forecast period, a disturbance or series of
disturbances appears set to eject from the southwestern CONUS
across the central Plains. This also appears, similar to so many
storm systems this winter, likely to interact with a trough diving
south into the region at the same general time. That said, the
interactions of these features result in another low confidence
forecast with fluctuations likely over the next few days. The take
away point would be that another round of winter weather is
possible by the second half of the work week, potentially focused
around the Thursday time frame.
&&
.AVIATION...(For the 18Z TAFs through 18Z Saturday Afternoon)
Issued at 1123 AM CST FRI FEB 20 2015
Confidence is good that IFR conditions will move into the
terminals by this evening. OBS upstream are already showing CIGS
around 1 KFT. Biggest uncertainty remains precip type. Think there
will be a mix or rain, freezing rain and snow during the
overnight. Think the precip will come to an end by 12Z. Have
trended optimistic with CIGS improving tomorrow morning, but there
is a chance for stratocu to hang in between 1 and 2 KFT through
the morning. See above discussion for further details.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY from 6 PM this evening to 9 AM CST
Saturday FOR KSZ012-024-026-038>040-054>056-058-059.
&&
$$
UPDATE...Wolters
SHORT TERM...Hennecke
LONG TERM...Barjenbruch
AVIATION...Wolters
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1030 AM CST Fri Feb 20 2015
.UPDATE...
Issued at 1030 AM CST FRI FEB 20 2015
12Z models data coming in and continue to show potential for mixed
precip this evening and overnight. Main uncertainty remains the
low level temp profile this evening and overnight with models all
within 1 to 2 C of freezing. The NAM is the colder solution which
would favor more snow. On the other hand the RAP tends to keep
surface temps above freezing and precip mainly rain through at
least 07Z. So with forecasts all within the margin of error, it
is difficult to predict the type of precip with much confidence
and would expect some combination of rain, freezing rain and snow
overnight.
As for accumulations the good news is with a weaker more
progressive system, models are not generating much moisture in
general with QPF amounts ranging from a couple hundredths over
north central KS to possibly a quarter of an inch over far
eastern KS. So worst case scenarios for accumulations would be 2 to
3 inches of snow or perhaps up to a quarter inch of ice
accumulation. Because the forecast anticipates mixed precip such
that precip is not all snow nor is it all ice, snow accumulations
are forecast be less than an inch and ice accumulations around a
tenth of an inch. This will probably be variable across northeast
and east central KS based on temps, but snow is more likely north
of I-70 and rain/freezing rain is more likely south of I-70. The
forecast anticipates the greatest impact to be west of a line from
Council Grove to Marysville.
Precip is still on track to come to an end before 8 AM Saturday
so the timing for the greatest impact remains during the evening
and overnight hours. Precip is expected to begin spreading north
across the area late this afternoon with temps above freezing. It
is between 7 PM and 10 PM when temps may fall to the freezing mark
and hazards start to be realized.
&&
.SHORT TERM...(Today and Tonight)
Issued at 248 AM CST FRI FEB 20 2015
The forecast for the short term remains quite challenging as we
continue to monitor the potential for a wintry mix of precipitation
tonight into Saturday morning.
At the surface, high pressure prevailed over the eastern U.S. with
low pressure situated over the Rockies, resulting in light
southeasterly winds, mostly clear to partly cloudy skies, and
temperatures early this morning plunging into the teens. Satellite
imagery showed a swath of low clouds stretching across Arkansas and
eastern Oklahoma as southerly flow in that region continued to
advect moisture northward. How quickly this cloud cover lifts into
the region and how expansive the cloud cover becomes will have a
significant impact on temperatures today. Current forecast has highs
reaching into the mid 30s to mid 40s from east to west, however if
the region quickly becomes blanketed by cloud cover then
temperatures may only reach into low to upper 30s. Model soundings
show increasing low level moisture in east central Kansas by mid to
late morning and continuing through this afternoon, so expect some
patchy freezing drizzle initially before warming up enough for
drizzle or even light rain this afternoon for locations generally
along and south of I-35. Moisture advection will strengthen by this
evening with light precipitation overspreading the region from south
to north. An advancing mid-level trough will help to push a cold
front through the region tonight into the early overnight hours, and
moisture associated with this boundary is expected to converge with
the southern stream moisture by mid to late evening. The last couple
of model runs have trended toward a faster departure of
precipitation from west to east so have decreased POPs across north
central Kansas during the overnight hours. The precipitation type
forecast continues to be quite challenging for tonight as it will be
very dependent upon how much we warm up today and at what rate
temperatures cool to near and below freezing tonight. As a result,
confidence in the precipitation type and QPF forecasts is
unfortunately still low. In general, focus has shifted more toward
concerns for ice accumulations with lesser snow accumulations than
previously expected. Expect areas of rain to gradually transition
to a wintry mix of freezing rain, sleet, and snow across most
locations. Locations along and south of I-35 should see predominantly
rain, freezing rain, and sleet, while locations north of I-35 should
see more of a mix of freezing rain, sleet, and snow. At this time,
snow accumulations look to be around one-half inch or less. Ice
accumulations upwards of around one tenth of an inch are possible
along and south of I-35 with lesser amounts to the north. With these
concerns for ice accumulations and the associated hazardous travel
conditions, a Winter Weather Advisory has been issued for counties
in far northeast and east central Kansas from 6pm tonight through
9am Saturday.
.LONG TERM...(Saturday through Thursday)
Issued at 248 AM CST FRI FEB 20 2015
Saturday morning may have a bit of lingering precipitation, but
should dry out quickly after sunrise (if not earlier). If any
precip does linger, temperatures are likely to be very near the
freezing mark with slightly warmer temperatures aloft so have a
mix of precip types possible. There also seems to be some
potential for flurries behind the main precip area and
particularly in north central KS so have included a mention of
that in the forecast for early Saturday as well. Otherwise, the
remainder of Saturday through Monday is dominated by strong
surface high pressure. This low level airmass will also be quite
dry and quite cold. The dry air will impact the forecast markedly
as there is persistent weak vertical motion aloft in central KS
through this period, but will likely result in little more than
virga over the local forecast area. Will need to monitor the
situation as minor changes in the forecast could result in a
persistent but light snow on the western and southern edges of the
forecast area...but this appears to be quite unlikely at this
time. Sunday looks to be the coldest day of the period as the high
pressure settles directly overhead. Clouds will keep daytime temps
cool, and if any clearing takes place Sunday night, the current
single digit forecast may be too warm.
By late in the forecast period, a disturbance or series of
disturbances appears set to eject from the southwestern CONUS
across the central Plains. This also appears, similar to so many
storm systems this winter, likely to interact with a trough diving
south into the region at the same general time. That said, the
interactions of these features result in another low confidence
forecast with fluctuations likely over the next few days. The take
away point would be that another round of winter weather is
possible by the second half of the work week, potentially focused
around the Thursday time frame.
&&
.AVIATION...(For the 12Z TAFs through 12Z Saturday Morning)
Issued at 536 AM CST FRI FEB 20 2015
For the 12Z TAFs, MVFR CIGS should lift northward toward the TAF
sites by late morning or early afternoon with areas of light rain
developing by late this afternoon into early evening. The forecast
for precipitation type through the evening and overnight hours will
be quite challenging as a wintry mix of freezing rain, sleet, and
snow is possible. This wintry mix of precipitation should continue
into Saturday morning, and hopefully future updates will be able to
further pinpoint the timing of various precipitation types. With the
mixed precipitation, CIGS/VSBY should drop to IFR conditions but
cannot rule out periods of near LIFR conditions. Once a cold front
tracks through the area tonight, southeasterly winds will gradually
back to the north-northwest by Saturday morning.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY from 6 PM this evening to 9 AM CST
Saturday FOR KSZ012-024-026-038>040-054>056-058-059.
&&
$$
UPDATE...Wolters
SHORT TERM...Hennecke
LONG TERM...Barjenbruch
AVIATION...Hennecke
AREA FORECAST DISCUSSION
NWS PADUCAH KY
1152 AM CST FRI FEB 20 2015
.UPDATE...
ISSUED AT 1151 AM CST FRI FEB 20 2015
THE AVIATION SECTION HAS BEEN UPDATED FOR THE 18Z TAF ISSUANCE.
UPDATE ISSUED AT 1100 AM CST FRI FEB 20 2015
ALREADY GETTING FREEZING RAIN AND SLEET OVER MUCH OF SOUTHEAST
MISSOURI THIS MORNING. SEE NO REASON WHY PRECIPITATION TYPES WILL
TREND COLDER THROUGH THE DAY...SO TRIED TO PUSH SLEET AND FREEZING
RAIN NORTHEAST ACROSS THE AREA A BIT FASTER THROUGH THE AFTERNOON.
THE PRECIPITATION HAS BEEN QUITE SHOWERY OVER SOUTHWEST PORTIONS
OF THE AREA...AND THE HRRR AND WRF RUNS INDICATE THAT THAT WILL
CONTINUE THROUGH THE DAY. DO NOT ANTICIPATE ANY CHANGES TO
HEADLINES AT THIS TIME.
UPDATE ISSUED AT 755 AM CST FRI FEB 20 2015
UPDATED THE FORECAST TO REFLECT CURRENT CONDITIONS AND LATEST
SHORT TERM MODEL DATA. THOUGH SOME MEASURABLE PCPN MAY FALL MAINLY
WEST OF THE MS RIVER IN THE MORNING...MOST OF THE PCPN WILL
PROBABLY WAIT UNTIL THE AFTERNOON TO SPREAD NEWD ACROSS THE REGION
TODAY.
ALSO UPDATED THE AVIATION DISCUSSION.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY NIGHT)
ISSUED AT 430 AM CST FRI FEB 20 2015
SO FAR...THE DEVELOPING WARM ADVECTION PATTERN DEVELOPING OVER THE
PAH FORECAST AREA HAS YIELDED MID CLOUDINESS AND NOTHING
MEASURABLE AT THE GROUND. HOWEVER...THAT IS EXPECTED TO CHANGE
PRIMARILY THIS AFTERNOON. MODEL SOUNDINGS INDICATE THAT THE PCPN
WILL START OUT AS SNOW...WITH SLEET INCREASINGLY MIXED IN MAINLY WEST
OF THE MS RIVER.
THE MOST INTERESTING TIME FRAME WILL BE THIS EVENING...WHEN WARM
AIR CONTINUES TO MOVE IN ALOFT. HOW MUCH DEPENDS ON WHICH MODEL
YOU BELIEVE. THE NAM HAD A MORE PRONOUNCED WARM TONGUE...BUT ALSO
COLDER SFC TEMPS THAN THE GFS...FOR EXAMPLE. SFC TEMP GRIDS WERE
BASED ON A BLEND OF MODEL DATA...AND THE FORECAST PCPN-TYPE WAS
BASED ON A COMPROMISE MAINLY BETWEEN THE GFS AND THE NAM. IT IS
BELIEVED THAT PCPN LOADING WILL PLAY A PART IN WARMING TEMPS
ACROSS THE REGION DURING THE EVENING.
AT THIS TIME...IN THE EVENING...AS THE SNOWFALL IS GRADUALLY
REPLACED BY A WINTRY MIX...IT APPEARS THE WINDOW OF OPPORTUNITY
FOR FREEZING RAIN...AND ICE ACCRETION...WILL BE RATHER NARROW.
EXCEPT FOR AREAS NORTH OF I-64...A FEW HOURS OF FREEZING RAIN IS
FORECAST IN THE EVENING ONLY. NORTH OF I-64...TIMING SHOULD BE
DELAYED UNTIL SHORTLY AFTER MIDNIGHT.
AS A VIGOROUS LOW PRESSURE SYSTEM PASSES THROUGH THE REGION ON
SAT...ALL RAIN SHOULD BE UNDERWAY AFTER DAYBREAK...WITH A
POSSIBILITY OF SOME HEAVY RAINFALL RATES ACROSS ROUGHLY THE SRN
THIRD OF THE PAH FORECAST AREA. A THUNDERSTORM OR TWO CANNOT BE
RULED OUT. PCPN WILL COME TO A RAPID END SAT NIGHT...WITH A
POSSIBLE WINTRY MIX FOR WRN KY LATE BEFORE DAYBREAK AS TEMPS CRASH
AGAIN BELOW FREEZING.
TOTAL SNOW AND SLEET ACCUMULATION IS EXPECTED TO BE GENERALLY
BETWEEN 1/2 INCH AND 2 INCHES.
THE MOST ICE ACCRETION SHOULD OCCUR NEAR THE TN STATE LINE...UP TO
AROUND 0.10 INCH...SOMEWHAT LESSER AMOUNTS OVER THE SRN HALF OF
SERN MO AND THE PURCHASE AREA OF KY...AND MAYBE A HUNDREDTH OF AN
INCH POSSIBLE ELSEWHERE.
.LONG TERM...(SUNDAY THROUGH THURSDAY)
ISSUED AT 430 AM CST FRI FEB 20 2015
LITTLE TO NO CHANGE TO THE UPPER AIR PATTERN IN THE LONG TERM.
PERSISTENT RIDGE OVER THE PACIFIC OFF THE WEST COAST AND LOW CENTERS
FROM GREENLAND TO HUDSON BAY WILL KEEP BROAD TROF AND LOW HEIGHTS
ACROSS MUCH OF THE NATION ESPECIALLY EAST OF THE ROCKIES. MAINLY DRY
WEATHER IS FORECAST WITH BELOW NORMAL TEMPERATURES. TWO MINOR
SYSTEMS COULD AFFECT THE AREA...ONE MONDAY NIGHT...WITH THE SECOND
THURSDAY INTO THURSDAY NIGHT. ONLY HAVE SLIGHT CHANCES IN FOR
THURSDAY AT THIS TIME FOR LIGHT SNOW.
&&
.AVIATION...
ISSUED AT 1151 AM CST FRI FEB 20 2015
THE FORECAST IS STILL ON TRACK WITH A RAPID WARMING TREND EXPECTED
THROUGH TONIGHT. ALL TAFS SHOULD SEE DETERIORATING CONDITIONS
TONIGHT WITH PRECIPITATION TYPE TRANSITIONING FROM SLEET/SNOW TO
FREEZING AND EVENTUALLY ALL RAIN BY 06Z. LOW CONFIDENCE ON WINDS
WITH A SURFACE TROUGH DEVELOPING NORTHEAST RIGHT ACROSS THE
TERMINALS. CANNOT RULE OUT SOME SOUTHERLY GUSTS TONIGHT.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...WINTER WEATHER ADVISORY UNTIL 6 AM CST SATURDAY FOR ILZ075>078-
080>094.
MO...WINTER WEATHER ADVISORY UNTIL 6 AM CST SATURDAY FOR MOZ076-086-
087-100-107>112-114.
IN...WINTER WEATHER ADVISORY UNTIL 6 AM CST SATURDAY FOR INZ081-082-
085>088.
KY...WINTER WEATHER ADVISORY UNTIL 6 AM CST SATURDAY FOR KYZ001>022.
&&
$$
UPDATE...DRS
SHORT TERM...DB
LONG TERM...CN
AVIATION...DRS
AREA FORECAST DISCUSSION
NWS PADUCAH KY
1100 AM CST FRI FEB 20 2015
.UPDATE...
ISSUED AT 1100 AM CST FRI FEB 20 2015
ALREADY GETTING FREEZING RAIN AND SLEET OVER MUCH OF SOUTHEAST
MISSOURI THIS MORNING. SEE NO REASON WHY PRECIPITATION TYPES WILL
TREND COLDER THROUGH THE DAY...SO TRIED TO PUSH SLEET AND FREEZING
RAIN NORTHEAST ACROSS THE AREA A BIT FASTER THROUGH THE AFTERNOON.
THE PRECIPITATION HAS BEEN QUITE SHOWERY OVER SOUTHWEST PORTIONS
OF THE AREA...AND THE HRRR AND WRF RUNS INDICATE THAT THAT WILL
CONTINUE THROUGH THE DAY. DO NOT ANTICIPATE ANY CHANGES TO
HEADLINES AT THIS TIME.
UPDATE ISSUED AT 755 AM CST FRI FEB 20 2015
UPDATED THE FORECAST TO REFLECT CURRENT CONDITIONS AND LATEST
SHORT TERM MODEL DATA. THOUGH SOME MEASURABLE PCPN MAY FALL MAINLY
WEST OF THE MS RIVER IN THE MORNING...MOST OF THE PCPN WILL
PROBABLY WAIT UNTIL THE AFTERNOON TO SPREAD NEWD ACROSS THE REGION
TODAY.
ALSO UPDATED THE AVIATION DISCUSSION.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY NIGHT)
ISSUED AT 430 AM CST FRI FEB 20 2015
SO FAR...THE DEVELOPING WARM ADVECTION PATTERN DEVELOPING OVER THE
PAH FORECAST AREA HAS YIELDED MID CLOUDINESS AND NOTHING
MEASURABLE AT THE GROUND. HOWEVER...THAT IS EXPECTED TO CHANGE
PRIMARILY THIS AFTERNOON. MODEL SOUNDINGS INDICATE THAT THE PCPN
WILL START OUT AS SNOW...WITH SLEET INCREASINGLY MIXED IN MAINLY WEST
OF THE MS RIVER.
THE MOST INTERESTING TIME FRAME WILL BE THIS EVENING...WHEN WARM
AIR CONTINUES TO MOVE IN ALOFT. HOW MUCH DEPENDS ON WHICH MODEL
YOU BELIEVE. THE NAM HAD A MORE PRONOUNCED WARM TONGUE...BUT ALSO
COLDER SFC TEMPS THAN THE GFS...FOR EXAMPLE. SFC TEMP GRIDS WERE
BASED ON A BLEND OF MODEL DATA...AND THE FORECAST PCPN-TYPE WAS
BASED ON A COMPROMISE MAINLY BETWEEN THE GFS AND THE NAM. IT IS
BELIEVED THAT PCPN LOADING WILL PLAY A PART IN WARMING TEMPS
ACROSS THE REGION DURING THE EVENING.
AT THIS TIME...IN THE EVENING...AS THE SNOWFALL IS GRADUALLY
REPLACED BY A WINTRY MIX...IT APPEARS THE WINDOW OF OPPORTUNITY
FOR FREEZING RAIN...AND ICE ACCRETION...WILL BE RATHER NARROW.
EXCEPT FOR AREAS NORTH OF I-64...A FEW HOURS OF FREEZING RAIN IS
FORECAST IN THE EVENING ONLY. NORTH OF I-64...TIMING SHOULD BE
DELAYED UNTIL SHORTLY AFTER MIDNIGHT.
AS A VIGOROUS LOW PRESSURE SYSTEM PASSES THROUGH THE REGION ON
SAT...ALL RAIN SHOULD BE UNDERWAY AFTER DAYBREAK...WITH A
POSSIBILITY OF SOME HEAVY RAINFALL RATES ACROSS ROUGHLY THE SRN
THIRD OF THE PAH FORECAST AREA. A THUNDERSTORM OR TWO CANNOT BE
RULED OUT. PCPN WILL COME TO A RAPID END SAT NIGHT...WITH A
POSSIBLE WINTRY MIX FOR WRN KY LATE BEFORE DAYBREAK AS TEMPS CRASH
AGAIN BELOW FREEZING.
TOTAL SNOW AND SLEET ACCUMULATION IS EXPECTED TO BE GENERALLY
BETWEEN 1/2 INCH AND 2 INCHES.
THE MOST ICE ACCRETION SHOULD OCCUR NEAR THE TN STATE LINE...UP TO
AROUND 0.10 INCH...SOMEWHAT LESSER AMOUNTS OVER THE SRN HALF OF
SERN MO AND THE PURCHASE AREA OF KY...AND MAYBE A HUNDREDTH OF AN
INCH POSSIBLE ELSEWHERE.
.LONG TERM...(SUNDAY THROUGH THURSDAY)
ISSUED AT 430 AM CST FRI FEB 20 2015
LITTLE TO NO CHANGE TO THE UPPER AIR PATTERN IN THE LONG TERM.
PERSISTENT RIDGE OVER THE PACIFIC OFF THE WEST COAST AND LOW CENTERS
FROM GREENLAND TO HUDSON BAY WILL KEEP BROAD TROF AND LOW HEIGHTS
ACROSS MUCH OF THE NATION ESPECIALLY EAST OF THE ROCKIES. MAINLY DRY
WEATHER IS FORECAST WITH BELOW NORMAL TEMPERATURES. TWO MINOR
SYSTEMS COULD AFFECT THE AREA...ONE MONDAY NIGHT...WITH THE SECOND
THURSDAY INTO THURSDAY NIGHT. ONLY HAVE SLIGHT CHANCES IN FOR
THURSDAY AT THIS TIME FOR LIGHT SNOW.
&&
.AVIATION...
ISSUED AT 755 AM CST FRI FEB 20 2015
SERLY WINDS AROUND 10 KTS AND VFR CIGS WILL BE THE RULE THROUGH
THE MORNING. THE DEVELOPING WARM ADVECTION PATTERN AHEAD OF A
VIGOROUS LOW PRESSURE SYSTEM...WILL FORCE CIGS TO DROP TO MVFR
LEVELS IN THE EARLY AFTERNOON IN THE WRN HALF OF THE REGION. ERN
TERMINALS WILL FOLLOW BY THE LATE AFTERNOON/EARLY EVENING. THE
MOST SIGNIFICANT ELEMENT WILL BE PCPN TYPE. A WINTRY MIX IS
FORECAST TODAY AND TONIGHT...WITH A FEW HOURS OF PRIMARILY
FREEZING RAIN LIKELY TO OCCUR STARTING AROUND SUNSET AT WRN
TERMINALS...AND MID EVENING AT THE ERN TERMINALS.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...WINTER WEATHER ADVISORY UNTIL 6 AM CST SATURDAY FOR ILZ075>078-
080>094.
MO...WINTER WEATHER ADVISORY UNTIL 6 AM CST SATURDAY FOR MOZ076-086-
087-100-107>112-114.
IN...WINTER WEATHER ADVISORY UNTIL 6 AM CST SATURDAY FOR INZ081-082-
085>088.
KY...WINTER WEATHER ADVISORY UNTIL 6 AM CST SATURDAY FOR KYZ001>022.
&&
$$
UPDATE...DRS
SHORT TERM...DB
LONG TERM...CN
AVIATION...DB
AREA FORECAST DISCUSSION
NWS GAYLORD MI
408 PM EST FRI FEB 20 2015
.NEAR TERM...(THIS EVENING THROUGH TONIGHT)
ISSUED AT 406 PM EST FRI FEB 20 2015
...WIDESPREAD GENERALLY LIGHT SNOW TONIGHT...
HIGH IMPACT WEATHER POTENTIAL: NARROW CORRIDOR OF HEAVIER SNOW
POSSIBLE WEST OF US-31 IN MANISTEE AND BENZIE COUNTIES AND OVER
PARTS OF FAR WESTERN MACKINAC COUNTY...OTHERWISE GENERALLY LIGHT
SNOW ACCUMULATIONS OVER THE REMAINDER OF THE AREA.
PRIMARY FORECAST CHALLENGES/CONCERNS: HOW FAR INLAND WILL ENHANCED
HEAVIER SNOW BAND OVER LAKE MICHIGAN GET INTO COASTAL AREAS.
DETAILS: ISENTROPIC UPGLIDE /285-270K SFC/ INCREASING ACROSS
NORTHERN MICHIGAN IN ADVANCE OF SHORTWAVE TROF OVER MN/NRN WI. TOP
DOWN SATURATION GRADUALLY YIELDING LIGHT SNOW OVER FAR WESTERN
PORTIONS OF THE AREA. LIGHT SNOW WILL OVERSPREAD THE ENTIRE AREA BY
EARLY THIS EVENING...WITH A 6 HOUR WINDOW OF FAVORABLE DYNAMICS
/ALBEIT SOMEWHAT LIMITED MOISTURE/. NOT THE MOST FAVORABLE CLOUD
MICROPHYSICS WITH BEST OMEGA NOT SQUARELY FOCUSED WITHIN THE DGZ FOR
MUCH OF THE SNOWFALL PERIOD. TRANSITORY NATURE OF THE SHORTWAVE
COMBINED WITH MID LEVEL MIXING RATIO/S ON THE ORDER OF 1-2 G/KG
POINT TOWARD A GENERAL 1-2 INCH SNOWFALL FOR MOST LOCATIONS.
THE EXCEPTION TO THIS IS OVER PARTS OF MANISTEE...BENZIE AND
MACKINAC COUNTIES...WHERE NORTH-SOUTH ORIENTED CONVERGENCE AREA
UP THE SPINE OF LAKE MICHIGAN WILL CREATE POCKETS OF HEAVIER SNOW.
HIGH RESOLUTION HRRR GUIDANCE SHOWS THIS ENHANCED LAKE MICHIGAN BAND
QUITE WELL...KEEPING IT NEAR/ALONG THE LAKE MICHIGAN COAST THIS
EVENING...POSSIBLY NOSING IT INTO FAR WESTERN MACKINAC COUNTY.
AFTER COLLABORATION WITH THE GRAND RAPIDS NWS OFFICE AND WITH THE
POTENTIAL FOR SOME LOCALIZED 3-5 INCH SNOWFALL AMOUNTS IN THE
WESTERN PARTS OF BENZIE-MANISTEE COUNTIES...WENT AHEAD AND ISSUED A
WINTER WEATHER ADVISORY THROUGH 7 AM SATURDAY. NO ADVISORY FOR
MACKINAC COUNTY...AS BEST CONVERGENCE REMAINS SOUTH OF THAT AREA AND
ENHANCED SNOWFALL POTENTIAL WOULD LIKELY ONLY IMPACT A SMALL PORTION
OF THE COUNTY /FAR WESTERN AREAS/.
WIDESPREAD SNOW ENDS FROM WEST-EAST AFTER MIDNIGHT AS THE SHORTWAVE
PULLS EAST AND BEST DYNAMICS DIMINISH. A MUCH "WARMER" NIGHT IN
STORE FOR THE AREA COMPARED TO LAST NIGHT /WHICH ISN`T EXACTLY
SAYING MUCH/ WITH LOW TEMPERATURES GENERALLY IN THE SINGLE DIGITS
ABOVE ZERO.
&&
.SHORT TERM...(SATURDAY THROUGH MONDAY)
ISSUED AT 406 PM EST FRI FEB 20 2015
HIGH IMPACT WEATHER POTENTIAL: ANOTHER COLD WAVE SUNDAY
NIGHT/MONDAY MORNING, BUT NOT AS COLD AS THIS MORNING.
FORECAST CHALLENGES: LES IMPACTS WITH MOST OF THE GREAT LAKES
COVERED AND LOW TEMPERATURES AS THE NEXT COLD WAVE MOVE INTO THE
UPPER GREAT LAKES SUNDAY/MONDAY.
(2/21)SATURDAY...AROUND 12Z, THE COLD FRONT BEGINS TO MOVE THROUGH
THE REGION. THE SOUTHWEST WINDS SHOULD BE TURNING WEST BY 12Z,
LEADING TO A SHORT PERIOD OF WESTERLY FETCH FOR THE LAKE SNOW. THE
ONLY ISSUE WITH ANY LES IS THE N LAKE MICHIGAN HAS LITTLE OPEN
WATER, AND MOST OF THE THAT IS SOUTH OF THE MANITOU ISLANDS. WIND
DIRECTIONS GIVE LIMITED FETCH AS THEY GET INTO N LOWER, AND EVEN E
UPPER. SO HAVE SCALED BACK THE POPS A BIT AS THE OVERALL AREA WILL
HAVE A LIGHT CLIPPER SNOW, WITH LITTLE ADDED LES ON THE BACK END.
WINDS AFTER 18Z BECOME MORE NW AND NNW SO MAY GET SOME MINOR SNOW
AND FLURRIES NORTH OF M-32 AS THE STREAM LINES POINT TO LITTLE TO
NOTHING HAPPENING AS THE ATMOSPHERE DRIES OUT AS WELL BY THE EARLY
EVENING.
SATURDAY NIGHT...THE 850-700 MB LAYER RH FALL TO AROUND 40% BY 00Z
AND WITH THE 850 MB TEMPERATURES OF -20C (AT 0Z)CROSSING THE ICE,
THE LES WILL BE ALMOST NON-EXISTENT THROUGH MOST OF THE NIGHT. 850
MB TEMPERATURES CONTINUE TO COOL TO AROUND -30C IN LAKE SUPERIOR,
PROVIDING SOME INSTABILITY, WITH THE MOISTURE AT 850-700 MB LAYER
INCREASING TO AROUND 80% SOME LES WOULD BE POSSIBLE, BUT LACK OF
OPEN WATER WILL BE DIFFICULT TO GET MUCH GOING.
(2/22)SUNDAY...THE AIR MASS LOOKS COLD OVERNIGHT INTO SUNDAY
MORNING, BUT THE MAIN PROBLEM IS THAT CLOUDS ARE EXPECTED TO MOVE
INTO THE REGION BY 12Z, WHICH WILL PROBABLY INHIBIT THE TEMPERATURES
FROM FALLING MUCH BELOW -20F. HOWEVER, CONSIDERING THE MODELS`
ABILITY TO GET THE CLOUDS RIGHT, WOULD NOT BE SURPRISED IF THE LOW
TEMPERATURES IN THE MORNING WILL BE COLDER THAN WE HAVE. THINK THAT
THE LOWER TEENS BELOW ZERO IDEA IS THE BEST IDEA FOR NOW, UNTIL THE
LIGHT SNOW GETS STARTED BY 18Z, MAYBE SOONER IF THE CLOUDS ENCROACH
AND THE INSTABILITY CAN GET ENOUGH MOISTURE TO PRODUCE SNOW. MINOR
SNOW ACCUMULATIONS ARE EXPECTED TO THROUGH 00Z. THE FLOW AND
MOISTURE IS EXPECTED TO CONTINUE OVERNIGHT.
(2/23)MONDAY...THE MORNING MAY TURN OUT DRY, BUT FOR NOW WILL
CONTINUE THE LIGHT SNOW CHANCE, AS THE EXTREME COLD AIR AND
RETREATING MOISTURE MAY PRODUCE MINOR ACCUMULATIONS. BY 18Z, THE
WINDS TURN WSW, SO THAT THERE COULD BE SOME LES IN THE EVENING JUST
BEFORE THE NEXT SYSTEM MOVES INTO THE UPPER GREAT LAKES.
&&
.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 406 PM EST FRI FEB 20 2015
CONTINUED COLD WITH PERIODS OF SNOW. A COLD FRONT ASSOCIATED WITH A
LOW PRESSURE SYSTEM NEAR JAMES BAY WILL EXTEND THROUGH
MICHIGAN...POSSIBLY PRODUCING SOME ACCUMULATING SNOWS THROUGHOUT THE
BEGINNING OF THE PERIOD AND MODERATING TEMPERATURES INTO THE 20S ON
SOUTHERLY WINDS AHEAD OF THIS COLD FRONT. A LARGE AREA OF HIGH
PRESSURE WILL BUILD IN BEHIND THIS DEPARTING SYSTEM AND DOMINATE
THROUGH THE REMAINING PERIOD...CONTINUING THE COLD TEMPERATURES
WHICH ARE FAR BELOW NORMAL FOR THIS TIME OF THE YEAR. WITH THE
ABNORMALLY COLD TEMPERATURES WILL ALSO COME THE CHANCES OF NUISANCE
LAKE CLOUDS AND SOME LAKE EFFECT SNOW SHOWERS WHERE OPEN WATERS
STILL REMAIN OVER PORTIONS OF LAKE MICHIGAN AND LAKE SUPERIOR.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1222 PM EST FRI FEB 20 2015
HIGH CONFIDENCE IN -SN AND IFR CONDITIONS DEVELOPING THIS
AFTERNOON/EVENING.
EXPECT -SN TO DEVELOP AT MBL/TVC/PLN THIS AFTERNOON...APN IN THE
EVENING. CIGS LOWERING TO MVFR...WITH IFR VSBYS LATE THIS
AFTERNOON AND EVENING. VSBYS WILL IMPROVE LATE TONIGHT INTO
SATURDAY AS SNOW EXITS EAST OF THE REGION. SCATTERED -SHSN
CONTINUING SATURDAY MORNING...ESPECIALLY AT MBL/TVC/PLN.
LLWS THIS EVENING AT MBL/TVC...WITH STRONGER SSW FLOW JUST OFF
THE DECK.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL 7 AM EST SATURDAY FOR MIZ025-031.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
NEAR TERM...KEYSOR
SHORT TERM...JSL
LONG TERM...TJL
AVIATION...KEYSOR
AREA FORECAST DISCUSSION...CORRECTED
NWS GRAND RAPIDS MI
333 PM EST FRI FEB 20 2015
LATEST UPDATE...
SYNOPSIS/SHORT TERM/LONG TERM/HYDRO
.SYNOPSIS...
ISSUED AT 333 PM EST FRI FEB 20 2015
AN APPROACHING ARCTIC COLD FRONT WILL SPREAD MOSTLY LIGHT SNOW
ACROSS THE AREA THIS AFTERNOON AND TONIGHT. LOCALIZED HEAVIER SNOW
IS EXPECTED AT THE LAKESHORE NORTH OF THE MUSKEGON AREA. THE SNOW
WILL LINGER SATURDAY AS ANOTHER LOW MOVES NORTHEAST ACROSS THE OHIO
VALLEY. LOCATIONS AROUND AND SOUTH OF I-94 COULD SEE UP TO A COUPLE
INCHES OF ADDITIONAL SNOW SATURDAY. ANOTHER CLIPPER LOW COULD BRING
SNOWY AND WINDY CONDITIONS ACROSS THE AREA TUESDAY COULD IMPACT
TRAVEL. OTHERWISE...LAKE EFFECT SNOW SHOWERS WILL BE VERY COMMON
THROUGH THE COMING WEEK.
THERE WILL BE A VERY BRIEF WARMUP WITH HIGH TEMPERATURES APPROACHING
30 ON SATURDAY. THEN COLD RETURNS IN FORCE SATURDAY NIGHT WITH HIGHS
GENERALLY IN THE TEENS AND LOWS IN THE SINGLE DIGITS OR BELOW ZERO
FOR THE REST OF THE COMING WORK WEEK.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 333 PM EST FRI FEB 20 2015
INCREASED FORECAST SNOW AMOUNTS TONIGHT ALONG THE LAKESHORE NORTH OF
WHITEHALL AND HOISTED AN ADVISORY. LUDINGTON VISIBILITIES ALREADY
HAVE BEEN AT OR BELOW HALF A MILE IN SNOW AND WE EXPECT THAT AREA
COULD EASILY SEE 5 INCHES OR MORE TOTAL ACCUMULATIONS OVERNIGHT.
CURRENT SURFACE OBSERVATIONS SHOW A SIGNIFICANT OFFSHORE COMPONENT
TO THE WINDS OVER OUR NORTHERN LAKESHORE AREA. HRRR GUIDANCE
INDICATES A STRENGTHENING CONVERGENCE ZONE PARALLEL TO AND BARELY
OFF THE LAKESHORE EARLY TONIGHT THAT SHOULD FOCUS BRIEFLY INTENSE
SNOWFALL RATES. THIS CONVERGENCE AREA AND ASSOCIATED SNOWFALL
SHOULD PUSH INLAND BY AROUND MIDNIGHT. ALTHOUGH THE ADVISORY IS
SET TO EXPIRE AT 7 AM SATURDAY...COULD EASILY SEE SNOWFALL RATES
DECREASING SIGNIFICANTLY AFTER MIDNIGHT.
WITH THIS UPPER TROUGH IS A DEVELOPING SURFACE LOW THAT TRACKS
NORTHEAST ACROSS THE OHIO VALLEY. WE ARE FAIRLY CERTAIN THAT IMPACTS
WITH THIS SHOULD BE MINIMAL WITH PERHAPS A COUPLE INCHES
ACCUMULATION NEAR JACKSON DURING THE DAY SATURDAY.
SATURDAY NIGHT AND SUNDAY SHOULD SEE PERSISTENT LAKE EFFECT WITH 850
MB TEMPERATURES DROPPING TOWARDS -25C. LIMITED MOISTURE AND
SUB-OPTIMAL MICROPHYSICS SHOULD LIMIT ADDITIONAL ACCUMULATIONS TO
AROUND A COUPLE INCHES NEAR THE LAKESHORE.
.LONG TERM...(MONDAY THROUGH FRIDAY)
ISSUED AT 333 PM EST FRI FEB 20 2015
NO SIGNIFICANT CHANGES TO LONG TERM FORECAST...STRONG CLIPPER COULD
BRING 35MPH+ WIND GUSTS ON TUESDAY WITH SNOW SQUALLS TUESDAY
NIGHT INTO WEDNESDAY. ANOTHER ARCTIC AIRMASS WILL KEEP TEMPERATURES
WELL BELOW NORMAL FOR THE END OF THE WEEK.
LATEST 12Z GUIDANCE REMAINS IN VERY GOOD AGREEMENT ON EVOLUTION OF
WEATHER PATTERN OVER THE NEXT WEEK. BASICALLY A CONTINUATION OF THE
CURRENT WEATHER WITH THE ANOMALOUS WEST COAST RIDGE AND DOWN STREAM
TROUGH CENTERED OVER GREAT LAKES. THERE IS HOWEVER SOME CHANCE OF A
TEMPORARY BREAKDOWN OF THIS PATTERN NEXT WEEKEND WHICH WOULD LEAD TO
NEAR NORMAL TEMPERATURES FOR THE END OF FEBRUARY.
OUR EVENTUAL MID-WEEK CLIPPER IS PRESENTLY NORTH OF BARROW...ALASKA.
IT IS FORECAST TO DIG SOUTHEASTWARD THROUGH WESTERN CANADA REACHING
THE UPPER GREAT LAKES ON TUESDAY WITH AN ALMOST CLOSED H500 LOW BY
WEDNESDAY. ALONG WITH IT COMES A SHOT OF SIBERIAN ARCTIC AIR.
THIS WOULD NORMALLY BE A GOOD SETUP FOR A SIGNIFICANT LAKE
ENHANCED EVENT...BUT HAVE A COUPLE OF CONCERNS. THE FIRST IS THE
THAT THE WAVE IS PRESENTLY IN A DATA SPARSE AREA OBSERVATION
WISE...SO WHILE THE TREND HAS BEEN STABLE AT PRESENT...WOULD NOT
BE SURPRISED BY A JUMP OR TWO IN THE FORECAST OVER THE NEXT COUPLE
OF DAYS. SECONDLY...LAKE MICHIGAN IS REALLY STARTING TO SLUSH UP
AND THAT WILL BEGIN TO LIMIT THE ABILITY OF THE LAKE TO ENHANCE
THE SYSTEM SNOWFALL. STAY TUNED...
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 111 PM EST FRI FEB 20 2015
NO SIGNIFICANT CHANGES TO CURRENT FORECAST...EXPECTING A PERIOD OF
1-3 MILE VSBY IFR SNOW TO MOVE THROUGH THE REGION TONIGHT WITH
SOME LAKE ENHANCED SNOW KMKG TO KLDM. ALSO SOME MAINLY LIGHT
TURBULENCE BELOW 030KFT THROUGH THIS EVENING.
MAINLY VFR/MVFR CONDITIONS EXPECTED ON SATURDAY WITH SCT IFR SNOW
SHOWER ACTIVITY ASSOCIATED WITH PASSAGE OF NEXT ARCTIC COLD
FRONT BY SAT EVE.
OUTLOOK...IFR LAKE EFFECT SNOW SHOWERS WEST OF KRQB - KGRR - KBTL
LINE ON SUNDAY WITH VFR/MVFR FLURRIES TO THE EAST WITH ANOTHER
SHOT OF ARCTIC AIR.
&&
.HYDROLOGY...
ISSUED AT 308 PM EST FRI FEB 20 2015
FAIRLY STEADY RIVER LEVELS ARE EXPECTED ACROSS THE AREA... WITH NO
SITES NEAR BANKFULL. TEMPERATURES WILL ONLY APPROACH FREEZING ON
SATURDAY WITH VALUES BELOW 20 DEGREES MOST OF THE WEEK. THIS SHOULD
RESULT IN THE ICE ON AREA RIVERS AND THE WATER IN THE SNOWPACK
REMAINING LOCKED UP. CURRENTLY... THERE ARE NO SUSPECTED ICE JAMS IN
THE AREA. SERIOUS ICE JAMS AND FLOODING CONCERNS ARE UNLIKELY UNTIL
A SIGNIFICANT WARM UP AND RAINFALL OCCUR.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL 7 AM EST SATURDAY FOR MIZ037-043-
050.
LM...NONE.
&&
$$
SYNOPSIS...TJT
SHORT TERM...TJT
LONG TERM...COBB
AVIATION...COBB
HYDROLOGY...63
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
315 PM EST FRI FEB 20 2015
LATEST UPDATE...
SYNOPSIS/SHORT TERM/LONG TERM/HYDRO
.SYNOPSIS...
ISSUED AT 308 PM EST FRI FEB 20 2015
AN APPROACHING ARCTIC COLD FRONT WILL SPREAD MOSTLY LIGHT SNOW
ACROSS THE AREA THIS AFTERNOON AND TONIGHT. LOCALIZED HEAVIER SNOW
IS EXPECTED AT THE LAKESHORE NORTH OF THE MUSKEGON AREA. THE SNOW
WILL LINGER SATURDAY AS ANOTHER LOW MOVES NORTHEAST ACROSS THE OHIO
VALLEY. LOCATIONS AROUND AND SOUTH OF I-94 COULD SEE UP TO A COUPLE
INCHES OF ADDITIONAL SNOW SATURDAY. SNOWY AND WINDY CONDITIONS
ACROSS THE AREA TUESDAY COULD IMPACT TRAVEL. OTHERWISE...LAKE EFFECT
SNOW SHOWERS WILL BE VERY COMMON THROUGH THE COMING WEEK.
THERE WILL BE A VERY BRIEF WARMUP WITH HIGH TEMPERATURES APPROACHING
30 ON SATURDAY. THEN COLD RETURNS IN FORCE SATURDAY NIGHT WITH HIGHS
GENERALLY IN THE TEENS AND LOWS IN THE SINGLE DIGITS OR BELOW ZERO
FOR THE REST OF THE COMING WORK WEEK.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 308 PM EST FRI FEB 20 2015
INCREASED FORECAST SNOW AMOUNTS TONIGHT ALONG THE LAKESHORE NORTH OF
WHITEHALL AND HOISTED AN ADVISORY. LUDINGTON VISIBILITIES ALREADY
HAVE BEEN AT OR BELOW HALF A MILE IN SNOW AND WE EXPECT THAT AREA
COULD EASILY SEE 5 INCHES OR MORE TOTAL ACCUMULATIONS OVERNIGHT.
CURRENT SURFACE OBSERVATIONS SHOW A SIGNIFICANT OFFSHORE COMPONENT
TO THE WINDS OVER OUR NORTHERN LAKESHORE AREA. HRRR GUIDANCE
INDICATES A STRENGTHENING CONVERGENCE ZONE PARALLEL TO AND BARELY
OFF THE LAKESHORE EARLY TONIGHT THAT SHOULD FOCUS BRIEFLY INTENSE
SNOWFALL RATES. THIS CONVERGENCE AREA AND ASSOCIATED SNOWFALL
SHOULD PUSH INLAND BY AROUND MIDNIGHT. ALTHOUGH THE ADVISORY IS
SET TO EXPIRE AT 7 AM SATURDAY...COULD EASILY SEE SNOWFALL RATES
DECREASING SIGNIFICANTLY AFTER MIDNIGHT.
WITH THIS UPPER TROUGH IS A DEVELOPING SURFACE LOW WE HAVE BEEN
WATCHING THAT TRACKS NORTHEAST ACROSS THE OHIO VALLEY. WE ARE FAIRLY
CERTAIN THAT IMPACTS WITH THIS SHOULD BE MINIMAL WITH PERHAPS A
COUPLE INCHES ACCUMULATION NEAR JACKSON DURING THE DAY SATURDAY.
SATURDAY NIGHT AND SUNDAY SHOULD SEE PERSISTENT LAKE EFFECT WITH 850
MB TEMPERATURES DROPPING TOWARDS -25C. LIMITED MOISTURE AND
SUB-OPTIMAL MICROPHYSICS SHOULD LIMIT ADDITIONAL ACCUMULATIONS TO
AROUND A COUPLE INCHES NEAR THE LAKESHORE.
.LONG TERM...(MONDAY THROUGH FRIDAY)
ISSUED AT 308 PM EST FRI FEB 20 2015
NO SIGNIFICANT CHANGES TO LONG TERM FORECAST...STRONG CLIPPER COULD
BRING 35MPH+ WIND GUSTS ON TUESDAY WITH SNOW SQUALLS TUESDAY
NIGHT INTO WEDNESDAY. ANOTHER ARCTIC AIRMASS WILL KEEP TEMPERATURES
WELL BELOW NORMAL FOR THE END OF THE WEEK.
LATEST 12Z GUIDANCE REMAINS IN VERY GOOD AGREEMENT ON EVOLUTION OF
WEATHER PATTERN OVER THE NEXT WEEK. BASICALLY A CONTINUATION OF THE
CURRENT WEATHER WITH THE ANOMALOUS WEST COAST RIDGE AND DOWN STREAM
TROUGH CENTERED OVER GREAT LAKES. THERE IS HOWEVER SOME CHANCE OF AT
LEAST A TEMPORARY BREAKDOWN OF THIS PATTERN NEXT WEEKEND WHICH WOULD
LEAD TO AT LEAST NEAR NORMAL TEMPERATURES FOR THE END OF FEBRUARY.
OUR EVENTUAL MID-WEEK CLIPPER IS PRESENTLY NORTH OF BARROW...ALASKA.
IT IS FORECAST TO DIG SOUTHEASTWARD THROUGH WESTERN CANADA REACHING
THE UPPER GREAT LAKES ON TUESDAY WITH AN ALMOST CLOSED H500 LOW BY
WEDNESDAY. ALONG WITH IT COMES A SHOT OF SIBERIAN ARCTIC AIR.
THIS WOULD NORMALLY BE A GOOD SETUP FOR A SIGNIFICANT LAKE
ENHANCED EVENT...BUT HAVE A COUPLE OF CONCERNS. THE FIRST IS THE
THAT THE WAVE IS PRESENTLY IN A DATA SPARSE AREA OBSERVATION
WISE...SO WHILE THE TREND HAS BEEN STABLE AT PRESENT...WOULD NOT
BE SURPRISED BY A JUMP OR TWO IN THE FORECAST OVER THE NEXT COUPLE
OF DAYS. SECONDLY...LAKE MICHIGAN IS REALLY STARTING TO SLUSH UP
AND THAT WILL BEGIN TO LIMIT THE ABILITY OF THE LAKE TO ENHANCE
THE SYSTEM SNOWFALL. STAY TUNED...
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 111 PM EST FRI FEB 20 2015
NO SIGNIFICANT CHANGES TO CURRENT FORECAST...EXPECTING A PERIOD OF
1-3 MILE VSBY IFR SNOW TO MOVE THROUGH THE REGION TONIGHT WITH
SOME LAKE ENHANCED SNOW KMKG TO KLDM. ALSO SOME MAINLY LIGHT
TURBULENCE BELOW 030KFT THROUGH THIS EVENING.
MAINLY VFR/MVFR CONDITIONS EXPECTED ON SATURDAY WITH SCT IFR SNOW
SHOWER ACTIVITY ASSOCIATED WITH PASSAGE OF NEXT ARCTIC COLD
FRONT BY SAT EVE.
OUTLOOK...IFR LAKE EFFECT SNOW SHOWERS WEST OF KRQB - KGRR - KBTL
LINE ON SUNDAY WITH VFR/MVFR FLURRIES TO THE EAST WITH ANOTHER
SHOT OF ARCTIC AIR.
&&
.HYDROLOGY...
ISSUED AT 308 PM EST FRI FEB 20 2015
FAIRLY STEADY RIVER LEVELS ARE EXPECTED ACROSS THE AREA... WITH NO
SITES NEAR BANKFULL. TEMPERATURES WILL ONLY APPROACH FREEZING ON
SATURDAY WITH VALUES BELOW 20 DEGREES MOST OF THE WEEK. THIS SHOULD
RESULT IN THE ICE ON AREA RIVERS AND THE WATER IN THE SNOWPACK
REMAINING LOCKED UP. CURRENTLY... THERE ARE NO SUSPECTED ICE JAMS IN
THE AREA. SERIOUS ICE JAMS AND FLOODING CONCERNS ARE UNLIKELY UNTIL
A SIGNIFICANT WARM UP AND RAINFALL OCCUR.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL 7 AM EST SATURDAY FOR MIZ037-043-
050.
LM...NONE.
&&
$$
SYNOPSIS...TJT
SHORT TERM...TJT
LONG TERM...COBB
AVIATION...COBB
HYDROLOGY...63
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
128 PM EST FRI FEB 20 2015
LATEST UPDATE...
SHORT TERM
.SYNOPSIS...
ISSUED AT 328 AM EST FRI FEB 20 2015
A CLIPPER WILL APPROACH LOWER MICHIGAN LATER TODAY AND SPREAD LIGHT
SNOW ACROSS IT LATE THIS AFTERNOON AND TONIGHT. A COUPLE OF INCHES
OF SNOW IS POSSIBLE WEST OF US-131 AND AROUND AN INCH EAST OF THERE.
THE SNOW WILL LINGER INTO SATURDAY AS ANOTHER LOW MOVES OVER THE
OHIO VALLEY. LOCATIONS SOUTH OF I-94 COULD SEE UP TO AN INCH OF SNOW
SATURDAY FROM THAT SYSTEM.
TEMPERATURES WILL BE WELL BELOW NORMAL TODAY WITH HIGHS IN THE
TEENS. HOWEVER TEMPERATURES WILL WARM UP SATURDAY AND APPROACH 30.
BEHIND THE CLIPPER SUNDAY TEMPERATURES WILL REMAIN MOSTLY IN THE
TEENS. IN FACT MUCH OF NEXT WEEK WILL SEE HIGHS IN THE TEENS.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 128 PM EST FRI FEB 20 2015
HAVE INCREASED FORECAST SNOW AMOUNTS TONIGHT ALONG THE LAKESHORE
NORTH OF WHITEHALL AND HAVE HOISTED AN ADVISORY. LUDINGTON
VISIBILITIES ARE ALREADY DOWN TO HALF A MILE IN SNOW AND THAT AREA
COULD EASILY SEE 5 INCHES OR MORE TOTAL ACCUMULATION OVERNIGHT.
CURRENT SURFACE OBSERVATIONS SHOW A SIGNIFICANT OFFSHORE COMPONENT
TO THE WINDS OVER OUR NORTHERN LAKESHORE AREA. HRRR GUIDANCE
INDICATES A STRENGTHENING CONVERGENCE ZONE PARALLEL TO AND BARELY
OFF THE LAKESHORE EARLY TONIGHT THAT SHOULD FOCUS BRIEFLY INTENSE
SNOWFALL RATES. THIS CONVERGENCE AREA AND ASSOCIATED SNOWFALL
SHOULD PUSH INLAND BY AROUND MIDNIGHT. ALTHOUGH THE ADVISORY IS
SET TO EXPIRE AT 7 AM SATURDAY...COULD EASILY SEE SNOWFALL RATES
DECREASING SIGNIFICANTLY AFTER MIDNIGHT.
THIS LOCALIZED FORCING WILL OCCUR AGAINST A BACKDROP OF LARGER SCALE
FORCING AS AN UPPER TROUGH DEVELOPS UPSTREAM. THIS SHOULD BE
SUFFICIENT FOR ACCUMULATIONS ACROSS THE ENTIRE FORECAST AREA.
WITH THIS UPPER TROUGH IS A DEVELOPING SURFACE LOW WE HAVE BEEN
WATCHING THAT TRACKS NORTHEAST ACROSS THE OHIO VALLEY. WE ARE FAIRLY
CERTAIN THAT IMPACTS WITH THIS SHOULD BE MINIMAL WITH PERHAPS A
COUPLE INCHES ACCUMULATION NEAR JACKSON DURING THE DAY SATURDAY.
.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 328 AM EST FRI FEB 20 2015
THE MOST SIGNIFICANT IMPACTS THIS COMING WEEK WILL BE WITH THE SNOW
SHOWERS...STRONG WIND AND COLD TEMPERATURES ASSOCIATED WITH THE NEXT
CLIPPER SYSTEM AS IT MOVES THROUGH THE AREA TUESDAY INTO WEDNESDAY.
ONCE THE CLIPPER MOVES THROUGH THE AREA WE WILL THEN BE WATCHING THE
LAKE ENHANCED SNOW SHOWERS WITH WIND CHILL ISSUES LATER WEDNESDAY
THROUGH THURSDAY.
THE LONG WAVE PATTERN REMAINS STABLE THROUGH THIS COMING WEEK WITH A
RIDGE OVER THE WESTERN UNITED STATES AND OFF THE WEST COAST OVER THE
EASTERN PACIFIC WITH A DOWNSTREAM TROUGH OVER THE EASTERN UNITED
STATES AND CANADA. THERE IS NO SIGN OF THIS BRAKING UP IN AT LEAST
THE NEXT WEEK OR SO. MEANING THE COLD WEATHER PATTERN WE CURRENTLY
HAVE WILL CONTINUE THROUGH THIS COMING WEEK.
A SERIES OF NORTHERN STREAM SHORTWAVES CONTINUES TO DIVE SOUTH
SOUTHEAST FROM THE ARCTIC INTO THE GREAT LAKES AREA THROUGH NEXT
WEEK. A WEAKER SYSTEM MOVES THROUGH THE AREA SUNDAY NIGHT INTO
MONDAY WITH LAKE ENHANCED SNOW SHOWERS (MOISTURE IS NOT VERY DEEP
BUT THERE IS ENOUGH TO ALLOW LAKE EFFECT SNOW SHOWERS). A MUCH
STRONGER SYSTEM FOLLOWS FOR TUESDAY INTO WEDNESDAY. THE ECMWF SHOWS
MORE DIGGING WITH THIS SYSTEM AN SINCE THAT IS THE TYPICAL MODEL
ERROR OF THE GFS (TO WEAK WITH NORTHERN STREAM SHORTWAVES) LIKELY
THE ECMWF WILL BE THE MORE CORRECT SOLUTION. THERE IS ANOTHER UPPER
LEVEL WAVE THAT TRAILS THIS SYSTEM FOR THURSDAY TO KEEP THE LAKE
EFFECT SNOW GOING AND BRING DOWN ANOTHER PERIOD OF 850 MB TEMPS
BELOW -20C (THAT KEEPS HIGHS HERE IN THE TEENS OR COLDER).
AS NOTED BY THE PREVIOUS SHIFT THE STRENGTH AND AMOUNT OF DIGGING OF
THE NORTHERN STREAM SHORTWAVE IS THE KEY TO HOW BIG AN EVENT THIS
WILL TURN OUT TO BE. NO MATTER WHICH IS CORRECT THERE WILL STILL BE
STRONG SOUTHWEST WINDS AHEAD OF THE SYSTEM WITH LAKE ENHANCED SNOW
TO OUR WEST AND NORTHWEST CWA. SOME BLOWING AND DRIFTING SNOW
TUESDAY AFTERNOON AND EVENING IS EXPECTED DUE TO THE STRONG WINDS.
THEN AS THE SYSTEM MOVES THROUGH WITH THE ASSOCIATED ARCTIC FRONT
NORTHWEST FLOW LAKE EFFECT SNOW SHOWERS WILL FOLLOW INTO AT LEAST
THURSDAY. LIKE THIS PAST EVENT LOW WIND CHILLS MAY BE AN ISSUE LATER
WEDNESDAY INTO THURSDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 111 PM EST FRI FEB 20 2015
NO SIGNIFICANT CHANGES TO CURRENT FORECAST...EXPECTING A PERIOD OF
1-3 MILE VSBY IFR SNOW TO MOVE THROUGH THE REGION TONIGHT WITH
SOME LAKE ENHANCED SNOW KMKG TO KLDM. ALSO SOME MAINLY LIGHT
TURBULENCE BELOW 030KFT THROUGH THIS EVENING.
MAINLY VFR/MVFR CONDITIONS EXPECTED ON SATURDAY WITH SCT IFR SNOW
SHOWER ACTIVITY ASSOCIATED WITH PASSAGE OF NEXT ARCTIC COLD
FRONT BY SAT EVE.
OUTLOOK...IFR LAKE EFFECT SNOW SHOWERS WEST OF KRQB - KGRR - KBTL
LINE ON SUNDAY WITH VFR/MVFR FLURRIES TO THE EAST WITH ANOTHER
SHOT OF ARCTIC AIR.
&&
.HYDROLOGY...
ISSUED AT 328 PM EST THU FEB 19 2015
FAIRLY STEADY RIVER LEVELS ARE EXPECTED ACROSS THE AREA... WITH NO
SITES NEAR BANKFULL. TEMPERATURES WILL ONLY APPROACH FREEZING ON
SATURDAY WITH VALUES BELOW 20 DEGREES MOST OF THE WEEK. THIS SHOULD
RESULT IN THE ICE ON AREA RIVERS AND THE WATER IN THE SNOWPACK
REMAINING LOCKED UP. CURRENTLY... THERE ARE NO SUSPECTED ICE JAMS IN
THE AREA.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL 7 AM EST SATURDAY FOR MIZ037-043-
050.
LM...NONE.
&&
$$
SYNOPSIS...04
SHORT TERM...TJT
LONG TERM...WDM
AVIATION...COBB
HYDROLOGY...63
AREA FORECAST DISCUSSION
NWS JACKSON MS
1015 AM CST FRI FEB 20 2015
.UPDATE...THE LIGHT FREEZING PRECIPITATION CONTINUES THIS MORNING
OVER THE EAST AND NORTHEAST PORTIONS OF THE AREA AS TEMPERATURES
CONTINUE TO RISE. EXPECT ALL OF THE TEMPERATURES ACROSS THE AREA TO
RISE ABOVE FREEZING BY 11AM-NOON TODAY. FREEZING RAIN ADVISORIES ARE
IN EFFECT UNTIL 11 AM THIS MORNING FOR AREAS GENERALLY ALONG AND
NORTH OF THE I-20 CORRIDOR. OCCASIONAL LIGHT RAIN WILL CONTINUE TO
BE POSSIBLE THIS AFTERNOON...ESPECIALLY OVER THE NORTHERN PORTIONS
OF THE AREA. MADE SEVERAL ADJUSTMENTS TO THE FORECAST THIS MORNING
AND THE UPDATES AREA ALREADY OUT./15/
.DISCUSSION...
TODAY THROUGH SATURDAY NIGHT...
COLD AND DRY AIR REMAINS LOCKED IN OVER THE ARKLAMISS THIS
MORNING WITH DEWPOINT TEMPERATURES STILL IN THE SINGLE DIGITS FOR THE
MOST PART...BUT A DEVELOPING WARM FRONT WILL MOVE NORTHEAST AND
ACROSS THE ENTIRE AREA BY SATURDAY MORNING BRINGING MUCH WARMER
TEMPERATURES. FOR NOW...THERE CONTINUES TO BE SOME CONCERN FOR LIGHT
FREEZING RAIN AS THE STRENGTHENING WARM ADVECTION ABOVE THE SHALLOW
COLD AIR CREATES A SUBSTANTIAL MID LEVEL WARM LAYER IN THE THERMAL
PROFILES. ISENTROPIC LIFT IS CAUSING WIDESPREAD STRATUS TO FORM WITH
LIGHT WINTRY PRECIP JUST NOW DEVELOPING OVER PORTIONS OF CENTRAL AR.
AM MOST CONCERNED WITH PRECIPITATION MOVING INTO THE GREENWOOD TO
COLUMBUS CORRIDOR LATER THIS MORNING GIVEN THAT IS WHERE SUB-FREEZING
SURFACE AIR WILL BE TOUGHER TO WARM. RECENT HRRR GUIDANCE SHOWS THAT
VERY LIGHT PRECIP WILL CONTINUE TO SPREAD EASTWARD FROM AR INTO NORTH
CENTRAL MS...BUT GIVEN DRY AIR IN PLACE IT APPEARS MEASURABLE PCPN
WILL LIKELY HOLD OFF UNTIL THE AFTN/EVNG. HAVING SAID THAT...LATEST
GFS BUFR SOUNDINGS INDICATE THE COLD AIR MAY HANG ON A BIT MORE THAN
ANTICIPATED SO WILL NEED TO MONITOR CLOSELY THIS TREND. WITH THAT
SAID...LATEST WPC/SREF PTYPE PROBS INDICATE THAT THE RISK FOR
MEASURABLE FZRA SHOULD MOVE NORTH OF THE AREA BEFORE 00Z.
THE FORECAST IS MORE STRAIGHT-FORWARD FROM TONIGHT INTO SATURDAY WITH
TEMPERATURES HOLD STEADY OR RISING THROUGH THE PERIOD IN STRONG WARM
ADVECTION. INCREASING MOISTURE CONVERGENCE ALONG AN APPROACHING COLD
FRONT WILL GENERATE SHOWER ACTIVITY - AND LOCALLY HEAVY RAINFALL WILL
BECOME POSSIBLE AS A FAIRLY ROBUST MOISTURE PLUME IS DRAWN NORTHWARD
AND COMBINES WITH INCREASING INSTABILITY TO BRING TSTM POTENTIAL. IN
ADDITION...SIGNIFICANT PRESSURE FALLS WILL RESULT IN RATHER GUSTY
SOUTH WINDS AND A FEW GUSTS TO 30 MPH WILL BE LIKELY TONIGHT IN THE
DELTA REGION. GUIDANCE HAS SPED UP THE SOUTHEASTWARD-MOVING COLD
FRONT BY ROUGHLY 12 HOURS AND IT IS NOW EXPECTED TO PASS THROUGH THE
ENTIRE AREA BY EARLY SUNDAY MORNING...SO THIS WILL HELP TO LIMIT
RAINFALL TOTALS. /EC/
SUNDAY THROUGH NEXT FRIDAY...COLD AND WET CURRENTLY LOOK TO SUM UP
THE LONG TERM PORTION OF THE FORECAST...THIS GO AROUND. LIGHT RAIN
WILL LINGER BEHIND THE FRONT ON SUNDAY AS STRONG COLD ADVECTION SETS
UP ACROSS THE REGION. WITH MOISTURE ALOFT STILL RESIDING OVER THE
AREA LATE SUNDAY NIGHT INTO MONDAY MORNING AS A DISTURBANCE ALOFT
RACES EAST THROUGH THE REGION...AND VERY COLD DRY AIR UNDERCUTTING IT
AT THE SURFACE AND IN THE LOWER LEVELS OF THE ATMOSPHERE...SOME LIGHT
WINTRY PRECIPITATION COULD FALL OVER THE NORTHERN HALF OF THE CWA
EARLY MONDAY MORNING.
CLOUDS AND LIGHT RAIN AGAIN LINGER MONDAY AS ANOTHER MID/UPPER LEVEL
DISTURBANCE IS PROGGED TO RACE EAST THROUGH THE REGION.
AGAIN...WITH FREEZING TO SUB-FREEZING OVERNIGHT LOWS FORECAST OVER
MUCH OF THE REGION MONDAY NIGHT INTO TUESDAY MORNING...COUPLED WITH
MOISTURE ALOFT OVER THE REGION...SOME LIGHT WINTERY PRECIPITATION
CAN`T BE RULED OUT.
AFTER A BRIEF...BUT CONTINUED COLD...BREAK FROM PRECIPITATION ON
TUESDAY...CHANCES FOR PRECIPITATION AGAIN INCREASE WEDNESDAY.
THIS IS AS A RESULT OF AN MID/UPPER LEVEL TROUGH THAT`LL SWING EAST
ACROSS THE NATION`S MID-SECTION...CAUSING A SURFACE LOW TO DEVELOP
AND SHIFT EAST ALONG THE THE NORTHERN GULF COAST. SMALL PRECIP
CHANCES REMAIN IN THE FORECAST THURSDAY INTO FRIDAY AS ONCE AGAIN A
SERIES OF DISTURBANCES ALOFT RACE EAST THROUGH THE CWA. /19/
&&
.AVIATION...MVFR CIGS WERE BEING REPORTED AT 16Z ALONG THE HWY 82
CORRIDOR WHERE LIGHT FREEZING RAIN...LIGHT SLEET AND LIGHT SNOW WL
BE PSBL THROUGH 17Z. TEMPERATURES WILL RISE THROUGH THE AFTN AND
LIGHT RAIN WILL CONTINUE. CIGS WL RISE ABOVE 3KFT THIS AFTN AS WELL.
WIDESPREAD STRATUS WL CONTINUE TONIGHT AS A STRONG WARM FRONT MOVES
NORTH THE AREA. VFR CATEGORY CIGS THIS AFTN WILL REDUCE TO MVFR
CATEGORY CIGS BY LATE TONIGHT AT MOST SITES AND MODERATE RAIN
CHANCES WILL INCREASE AS WELL. /22/
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 53 51 67 48 / 21 56 66 84
MERIDIAN 48 45 65 51 / 13 47 49 82
VICKSBURG 58 55 70 44 / 25 73 74 85
HATTIESBURG 56 50 68 57 / 14 38 42 81
NATCHEZ 59 56 70 49 / 19 64 67 85
GREENVILLE 49 49 65 37 / 57 84 88 65
GREENWOOD 48 48 64 39 / 48 86 85 81
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
/EC/19/
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1203 PM CST FRI FEB 20 2015
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 330 AM CST FRI FEB 20 2015
PCPN CHANCES AND PCPN TYPE TONIGHT ACROSS OUR SOUTHERN COUNTIES
AND TEMPERATURES FOR ALL OF THE AREA THE NEXT FEW DAYS WILL
PROVIDE THE MAIN FORECAST CHALLENGES.
LARGE SCALE PATTERN AT 500 MB FEATURES A TROUGH FROM THE EASTERN
PACIFIC UP INTO ALASKA. TWO CLOSED LOWS WERE NOTED...ONE OVER NEW
YORK STATE AND THE OTHER OVER THE NORTHERN PART OF HUDSON BAY. OUR
AREA WAS IN NORTHWEST FLOW. 12 HOUR HEIGHT FALLS OF UP TO 60 METERS
WERE NOTED LAST EVENING FROM EASTERN WASHINGTON STATE INTO WESTERN
MONTANA. THROUGH SATURDAY THE RIDGE TO THE WEST WILL AMPLIFY A
BIT AND MOVE EAST...THEN A REX BLOCK FORMS BY SUNDAY.
TODAY WILL BE FAIRLY MILD AS THE ARCTIC AIRMASS WHICH HAS BEEN
OVER OUR AREA THE PAST COUPLE OF DAYS HAS LOOSENED ITS GRIP. WITH
WINDS GETTING MORE OF A WESTERLY COMPONENT TODAY...MOST LOCATIONS
SHOULD TOP OUT IN THE 30S AND 40S. NORTHEAST NEBRASKA APPEARS TO
HAVE THE BEST CHANCE OF SEEING MID 40S OR POSSIBLY EVEN WARMER.
EXPECT MOST OF THE AREA TO HAVE A GOOD AMOUNT OF MID AND/OR HIGH
LEVEL CLOUDS WHICH WILL DAMPEN WARMING A BIT. THERE IS SOME
QUESTION WHETHER LIGHT PCPN WILL DEVELOP OVER PARTS OF SOUTHEAST
NEBRASKA THIS AFTERNOON. LATEST HRRR AND 13 KM RAP MODELS KEEP
THINGS DRY...SO WILL TREND THAT WAY FOR NOW EVEN THOUGH SOME OTHER
MODELS DO SHOW SOME LIGHT AMOUNTS ARE POSSIBLE. THIS MAY NEED SOME
ADJUSTMENT LATER TODAY.
WINDS WILL TURN TO THE NORTH OR NORTHWEST TONIGHT AS YET ANOTHER
COLD FRONT SAGS SOUTHWARD ACROSS THE REGION. SOME FLURRIES WILL BE
POSSIBLE LATER TONIGHT AND INTO SATURDAY...ESPECIALLY NORTH. THE
MAIN PCPN WILL STAY ACROSS KANSAS AND MISSOURI...BUT HELD ONTO SOME
CHANCE POPS IN OUR SOUTHERN COUNTIES TO BLEND IN WITH NEIGHBORS TO
THE SOUTH. NAM/GFS AND ECMWF ALL HINT AT SOME MIXED PCPN. ADDED A
SLIGHT CHANCE THIS EVENING UP AS FAR NORTH AS OMAHA/COUNCIL
BLUFFS. THE PCPN TYPE COULD BE RAIN OR SNOW EARLY ON...THEN A MIX
OF RAIN/FREEZING RAIN/SNOW DEPENDING ON SURFACE TEMPERATURES. THE
00Z GFS AND 06Z NAM MODELS SEEMED JUST A BIT OVERDONE WITH QPF
ALONG THE KANSAS AND MISSOURI BORDERS TONIGHT.
TEMPERATURES SHOULD SLOWLY SLIDE DURING THE DAY SATURDAY AS COLD AIR
SETTLES SOUTH AHEAD OF A 1045 MB HIGH THAT WILL BUILD INTO SOUTHERN
SASKATCHEWAN BY SATURDAY EVENING...THEN TO THE EASTERN DAKOTAS BY
SUNDAY EVENING. EXPECT HIGHS SUNDAY TO ONLY BE IN THE TEENS. LOWS
SATURDAY NIGHT WILL BE SINGLE DIGITS...THEN MAINLY AROUND ZERO TO 5
ABOVE FOR SUNDAY NIGHT.
.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 330 AM CST FRI FEB 20 2015
TEMPERATURES WILL START TO MODERATE MONDAY...WITH HIGHS IN THE 20S.
THAT TREND SHOULD CONTINUE TUESDAY WITH HIGHS IN THE 30S...BUT A
COLD FRONT WILL PUSH THROUGH IN THE AFTERNOON. THEN BELOW NORMAL
TEMPERATURES SHOULD LAST INTO LATE WEEK.
BOTH THE 00Z GFS AND 00Z ECMWF AGREE THAT SOME LIGHT SNOW MAY
DEVELOP AS EARLY AS WEDNESDAY BUT CHANCES ARE A BIT HIGHER FOR
WEDNESDAY NIGHT...ESPECIALLY FOR OUR WESTERN COUNTIES. NOT OVERLY
CONFIDENT ON THIS AND TIMING WILL PROBABLY NEED SOME ADJUSTMENT
WITH FUTURE FORECASTS.
&&
.AVIATION...(18Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 1158 AM CST FRI FEB 20 2015
WE HAVE OPTED TO KEEP THE FORECAST DRY FOR THE TAF SITES IN
EASTERN NEBRASKA THROUGH 18Z SATURDAY. AN AREA OF LOW PRESSURE
WILL BRING PRECIPITATION TO AREAS SOUTH OF THE TAF SITES
TONIGHT...BUT DRY AIR OVER THE TAF SITES SHOULD PROHIBIT ANY RAIN
OR SNOW FROM REACHING THE GROUND. CIGS WILL LOWER TO AROUND FL
025-040 OVERNIGHT...THEN THE INCREASE AGAIN SATURDAY MORNING.
A COLD FRONT WILL MOVE THROUGH AND CAUSE NORTHWEST WINDS TO GUST
TO AROUND 20 KNOTS LATE MORNING SATURDAY.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
SHORT TERM...MILLER
LONG TERM...MILLER
AVIATION...NIETFELD
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1215 PM CST FRI FEB 20 2015
.UPDATE...
ISSUED AT 1215 PM CST FRI FEB 20 2015
NO CHANGES NEEDED FOR THIS UPDATE.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 300 AM CST FRI FEB 20 2015
SNOW CHANCES TODAY AND TONIGHT WILL BE THE MAIN FORECAST
CHALLENGE...THEN WINDS TOMORROW.
NORTHWESTERLY FLOW ALOFT CONTINUES OVER THE NORTHERN PLAINS AND WV
LOOP SHOWS SEVERAL WEAK SHORTWAVES UPSTREAM. THE FIRST SHORTWAVE
CURRENTLY IS DIGGING INTO NORTHEASTERN SOUTH DAKOTA...AND THERE
HAS BEEN SOME LIGHT SNOW IN THE WARM AIR ADVECTION AHEAD OF THE
SFC LOW CURRENTLY ENTERING THE NORTHEASTERN CWA. THE LIGHT SNOW
HAS STARTED TO COME TO AN END ACROSS THE NORTHWESTERN
COUNTIES...SO THE TREND IN POPS TO PUSH HIGHEST PROBABILITIES OFF
TO THE EAST THIS MORNING SEEMS GOOD. THE RAP HAS THE NEXT WEAK
SHORTWAVES COMING THROUGH MAINLY ACROSS CENTRAL AND WESTERN
ND...WHICH FITS WITH CURRENT CANADIAN RADAR. MUCH OF THE SNOW FROM
THESE SHORTWAVES WILL REMAIN TO OUR WEST BUT CONTINUED TO KEEP
SOME LOW POPS IN OUR WESTERN COUNTIES IN CASE SOME LIGHT SNOW
CLIPS THAT AREA. WITH THE FIRST MORNING SHORTWAVE MOVING EAST AND
THE NEXT SHORTWAVES MAINLY FOCUSED ON THE FAR WESTERN TIER...THINK
THAT THERE WILL BE A PERIOD FOR THE CENTRAL CWA TODAY WHERE ONLY
LINGERING FLURRIES REMAINS. EVEN THOSE AREAS THAT GET ACCUMULATION
WILL SEE A HALF AN INCH AT MOST. THERE SHOULD BE ANOTHER LOW
CHANCE FOR ACCUMULATING SNOW AREA WIDE AS THE ARCTIC FRONT COMES
DOWN TONIGHT...BUT AGAIN IT WILL BE A DUSTING AT MOST.
TEMPS SHOULD BE FAIRLY MILD TODAY WITH GWINNER ALREADY AT 21
DEGREES AT 08Z. CONTINUED TO KEEP HIGHS IN THE TEENS IN THE NORTH
TO LOW 30S IN THE SOUTH. THE MILD TEMPS WILL END TONIGHT AS ARCTIC
AIR PLUNGES BACK SOUTH INTO THE CWA. WITH THE UPPER TROUGH DIGGING
DOWN OUT OF CANADA...ALL MODELS HAVE 850MB TEMPS BACK BELOW -20 C
FOR SATURDAY. CONTINUED TO KEEP HIGHS EITHER SIDE OF ZERO. WITH
COLD AIR ADVECTION AND A DECENT GRADIENT AHEAD OF THE ARCTIC
HIGH...NORTH WINDS COULD BECOME RATHER BREEZY SATURDAY. THE
BLOWING SNOW MODEL DOES NOT GIVE MUCH PROBABILITY DUE TO NO
FALLING SNOW AT THE TIME...BUT WILL HAVE TO WATCH WINDS ON
SATURDAY AS 925MB SPEEDS GET UP TO 25 KTS. THE WINDS WILL ALSO
KNOCK APPARENT TEMPS DOWN BELOW ADVISORY CRITERIA AT TIMES
ALTHOUGH TIMING IS STILL UNCERTAIN AT THIS POINT.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 300 AM CST FRI FEB 20 2015
SATURDAY NIGHT THROUGH SUNDAY NIGHT...CONDITIONS WILL REMAIN DRY
BUT COLD AS ARCTIC HIGH PRESSURE CONTINUES TO BUILD INTO THE AREA.
DEPENDING ON HOW MUCH WE CLEAR OUT...TEMPS SATURDAY NIGHT COULD
FALL BELOW 20 BELOW AND WITH SOME GRADIENT REMAINING...WIND CHILLS
MAY BE LOWER THEN 40 BELOW BY SUNDAY MORNING. THE SFC HIGH CENTER
BUILDING IN ON SUNDAY WILL CONTINUE WITH FRIGID TEMPS NOT RISING
INTO THE POSITIVE DIGITS. THE SFC HIGH WILL BEGIN TO SINK
SOUTHEASTWARD SUNDAY NIGHT AND WINDS WILL START PICKING UP WITH
SOME WARM AIR ADVECTION LATE IN THE NIGHT. TEMPS MAY START RISING
IN THE WEST...BUT NOT BEFORE BOTTOMING OUT IN THE TEENS BELOW
ZERO.
MONDAY THROUGH THURSDAY...THE EXTENDED BEGINS WITH A PAIR OF UPPER LEVEL
DISTURBANCES UPSTREAM IN CENTRAL CANADA. THE FIRST/WEAKER WAVE MAY
BRING A FEW FLURRIES TO THE AREA MONDAY AFTERNOON/EVENING...BUT A
BETTER CHANCE LOOKS TO COME LATER IN THE NIGHT WITH THE SECOND
WAVE. STILL...MOISTURE LOOKS LIMITED. SURFACE WINDS WILL BE
SOUTHWESTERLY ON MONDAY AHEAD OF A COLD FRONT ASSOCIATED WITH THE
SURFACE LOW PRESSURE SYSTEM. TEMPS AT 850 MB WARM CONSIDERABLY
FROM SUNDAY MORNING TO MONDAY MORNING... NEARLY 20C IN 30 HRS. THE
RESULT WILL BE HIGHS ABOUT 30 DEGREES WARMER ON MONDAY THAN ON
SUNDAY. THE COLD FRONT WILL THEN BARREL THROUGH THE AREA ON
TUESDAY MORNING. THE GOOD NEWS IS THAT IT IS EXPECTED TO BE A
GLANCING BLOW...WITH THE COLDEST AIR OFF TO THE EAST OVER FAR NE
MN AND LAKE SUPERIOR. THE BAD NEWS IS THAT STAGNANT COLD HIGH
PRESSURE WILL SET UP OVER THE NORTHERN PLANS TO END THE WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1215 PM CST FRI FEB 20 2015
MVFR CONDITIONS CONTINUING WITH WINDS BECOMING NORTHERLY BEHIND A
LOW PRESSURE SYSTEM. SOME SCT -SN WILL OCCUR OVER THE AREA BUT WILL
DIMINISH BY LATE AFTERNOON. CONDITIONS EXPECTED TO BECOME VFR LATE
IN THE PERIOD AS HIGH PRESSURE AND SUBSIDENCE SHIFTS OVER THE AREA.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...DK
SHORT TERM...JR
LONG TERM...JR/KNUTSVIG
AVIATION...HOPKINS
AREA FORECAST DISCUSSION
NWS NORMAN OK
1204 PM CST FRI FEB 20 2015
.AVIATION...
18Z...MOISTURE RETURN THIS MORNING IS RESULTING IN SOME
FOG...MAINLY IN WEST CENTRAL OKLAHOMA. HOWEVER...EXPECT SOME
IMPROVEMENT IN CEILINGS AND VISIBILITY THIS AFTERNOON ON
WESTERN EDGE OF CLOUD SHIELD. LATER THIS
AFTERNOON/EVENING...EXPECT WINDS WILL BACK WITH A BETTER CHANCE
FOR DRIZZLE AND SOME RESTRICTION TO VISIBILITY IN CENTRAL
OKLAHOMA. AS A SURFACE FRONTAL BOUNDARY STRENGTHENS ACROSS THE
AREA TONIGHT...PERHAPS THERE WILL BE A BETTER CHANCE OF VERY LOW
CLOUDS AND DRIZZLE. AS COLD AIR ADVECTION INCREASES AND SPREAD
SOUTHWARD TONIGHT...DRIZZLE AND VISIBILITY ISSUES WILL IMPROVE
THROUGH SATURDAY MORNING. FOR NOW...BETTER CHANCE FOR ELEVATED
STORMS...SHOULD REMAIN EAST OF ALL TAF SITES.
&&
.PREV DISCUSSION... /ISSUED 1106 AM CST FRI FEB 20 2015/
UPDATE...
MADE A FEW MINOR TWEAKS TO LOWER TEMPERATURES ACROSS THE
NORTH...WHERE NORTHEASTERLY WINDS CONTINUE. DONT EXPECT MUCH
WARMING IN THESE AREAS WITH OVERCAST SKIES. OTHERWISE...ADDED
MENTION OF PATCHY FOG AND DRIZZLE THROUGH THE DAY.
FORTUNATELY...IT LOOKS TO REMAIN WARM ENOUGH THAT ANY PRECIP THAT
FALLS WILL BE OF THE LIQUID VARIETY.
PREV DISCUSSION... /ISSUED 542 AM CST FRI FEB 20 2015/
AVIATION...
STRATUS CONTINUES TO SPREAD NORTH AND WEST MOVING INTO KOUN..
KOKC.. KPNC AND KLAW VERY SOON. WENT PRIMARILY WITH THE HRRR MODEL
ON HOW FAR WEST TO BRING THE STRATUS /VERY NEAR KHBR.. KCSM AND
KSPS AND NOT INTO KGAG AND KWWR/... BUT WILL BE WATCHING TRENDS.
THE TIMING OF THE STRATUS MOVING OUT OF THE AREA IS STILL VERY
MUCH IN QUESTION. HAVE BEEN LESS AGGRESSIVE WITH FOG DEVELOPMENT
GIVEN THE TIMING OF THE STRONGER SURFACE MOISTURE ADVECTION. A
COLD FRONT WILL MOVE THROUGH THE AREA THIS EVENING BRINGING A
BRISK NORTH WIND. GFS WOULD SUGGEST THAT THESE NORTH WINDS COULD
BE STRONGER THIS EVENING AND OVERNIGHT BEHIND THE COLD FRONT.
PREV DISCUSSION... /ISSUED 401 AM CST FRI FEB 20 2015/
DISCUSSION...
IT IS A COMPLEX WEATHER FORECAST THIS MORNING. MOISTURE ADVECTION
CONTINUES FROM THE SOUTHEAST THIS MORNING AND WITH THIS WILL BE A
CHANCE OF FOG/DRIZZLE THIS MORNING AND AT LEAST SOME LOW CHANCES
OF RAIN IN THE SOUTHEAST. TEMPERATURES WILL BE WARMER... ALTHOUGH
THE POTENTIAL ACROSS THE EASTERN HALF OF THE AREA WILL BE
MODERATED BY CLOUD COVER. DOWNSLOPE COMPONENT AND VERY WARM
TEMPERATURES IN THE LOW-LEVELS OF THE ATMOSPHERE WILL MAKE IT
QUITE WARM IN OUR TEXAS COUNTIES TODAY. COLD FRONT SWEEPS ACROSS
THE AREA TONIGHT WITH PRECIPITATION CHANCES CONTINUING... MAINLY
ACROSS THE EAST AND NORTH. SOME ELEVATED INSTABILITY DEVELOPS
GIVING A CHANCE OF THUNDERSTORMS OVERNIGHT ACROSS SOUTHERN AND
EASTERN OKLAHOMA. TEMPERATURES TOMORROW WILL STILL BE SEASONABLE
DESPITE THE FRONT OVERNIGHT.
A REINFORCING SHOT OF COLD AIR MOVES INTO THE AREA ON SUNDAY AND
REMINDS US THAT IT IS STILL WINTER. PRECIPITATION CHANCES PERSIST
INTO MONDAY WITH ENOUGH COLD AIR MOVING INTO THE AREA TO SUPPORT
WINTER PRECIPITATION. PRECIPITATION AMOUNTS MAY NOT BE TOO HIGH...
BUT WITH WINTER PRECIPITATION CHANCES SUNDAY AND MONDAY... MAY
HAVE SOME AREAS SLOWLY ACCUMULATE A COUPLE OF INCHES OF SNOW.
THERE IS ALSO SOME QUESTION IN THE MODELS ABOUT SUFFICIENT
HUMIDITY IN THE ICE CRYSTAL GROWTH LAYER AT TIMES TO KEEP FREEZING
RAIN IN THE DISCUSSION. RIGHT NOW WILL CONTINUE TO GO MOSTLY WITH
SNOW ALTHOUGH I HAVE MENTIONED FREEZING RAIN IN SOME AREAS ON
MONDAY. WILL CONTINUE TO WATCH TRENDS AS THIS DEVELOPS.
MOVING INTO MID-WEEK... FORECAST CONFIDENCE REMAINS LOW AS MEDIUM
RANGE MODELS DIFFER IN THE LOCATIONS OF THE LONGWAVE TROUGH IN THE
WEST AND THE WEAK RIDGE AHEAD OF IT SOMEWHERE IN THE ROCKIES OR
THE PLAINS. HOWEVER THERE IS REASONABLE AGREEMENT LATER IN THE
WEEK /JUST BEYOND THIS FORECAST PERIOD/ OF THE POTENTIAL OF MUCH
COLDER AIR SLIDING DOWN THE PLAINS.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 40 54 25 33 / 20 10 20 30
HOBART OK 39 54 27 33 / 0 0 10 20
WICHITA FALLS TX 46 59 31 38 / 0 0 10 30
GAGE OK 33 48 20 27 / 10 10 50 40
PONCA CITY OK 35 50 21 29 / 40 10 20 20
DURANT OK 51 61 32 41 / 30 20 10 40
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NORMAN OK
1106 AM CST FRI FEB 20 2015
.UPDATE...
MADE A FEW MINOR TWEAKS TO LOWER TEMPERATURES ACROSS THE
NORTH...WHERE NORTHEASTERLY WINDS CONTINUE. DONT EXPECT MUCH
WARMING IN THESE AREAS WITH OVERCAST SKIES. OTHERWISE...ADDED
MENTION OF PATCHY FOG AND DRIZZLE THROUGH THE DAY.
FORTUNATELY...IT LOOKS TO REMAIN WARM ENOUGH THAT ANY PRECIP THAT
FALLS WILL BE OF THE LIQUID VARIETY.
&&
.PREV DISCUSSION... /ISSUED 542 AM CST FRI FEB 20 2015/
AVIATION...
STRATUS CONTINUES TO SPREAD NORTH AND WEST MOVING INTO KOUN..
KOKC.. KPNC AND KLAW VERY SOON. WENT PRIMARILY WITH THE HRRR MODEL
ON HOW FAR WEST TO BRING THE STRATUS /VERY NEAR KHBR.. KCSM AND
KSPS AND NOT INTO KGAG AND KWWR/... BUT WILL BE WATCHING TRENDS.
THE TIMING OF THE STRATUS MOVING OUT OF THE AREA IS STILL VERY
MUCH IN QUESTION. HAVE BEEN LESS AGGRESSIVE WITH FOG DEVELOPMENT
GIVEN THE TIMING OF THE STRONGER SURFACE MOISTURE ADVECTION. A
COLD FRONT WILL MOVE THROUGH THE AREA THIS EVENING BRINGING A
BRISK NORTH WIND. GFS WOULD SUGGEST THAT THESE NORTH WINDS COULD
BE STRONGER THIS EVENING AND OVERNIGHT BEHIND THE COLD FRONT.
PREV DISCUSSION... /ISSUED 401 AM CST FRI FEB 20 2015/
DISCUSSION...
IT IS A COMPLEX WEATHER FORECAST THIS MORNING. MOISTURE ADVECTION
CONTINUES FROM THE SOUTHEAST THIS MORNING AND WITH THIS WILL BE A
CHANCE OF FOG/DRIZZLE THIS MORNING AND AT LEAST SOME LOW CHANCES
OF RAIN IN THE SOUTHEAST. TEMPERATURES WILL BE WARMER... ALTHOUGH
THE POTENTIAL ACROSS THE EASTERN HALF OF THE AREA WILL BE
MODERATED BY CLOUD COVER. DOWNSLOPE COMPONENT AND VERY WARM
TEMPERATURES IN THE LOW-LEVELS OF THE ATMOSPHERE WILL MAKE IT
QUITE WARM IN OUR TEXAS COUNTIES TODAY. COLD FRONT SWEEPS ACROSS
THE AREA TONIGHT WITH PRECIPITATION CHANCES CONTINUING... MAINLY
ACROSS THE EAST AND NORTH. SOME ELEVATED INSTABILITY DEVELOPS
GIVING A CHANCE OF THUNDERSTORMS OVERNIGHT ACROSS SOUTHERN AND
EASTERN OKLAHOMA. TEMPERATURES TOMORROW WILL STILL BE SEASONABLE
DESPITE THE FRONT OVERNIGHT.
A REINFORCING SHOT OF COLD AIR MOVES INTO THE AREA ON SUNDAY AND
REMINDS US THAT IT IS STILL WINTER. PRECIPITATION CHANCES PERSIST
INTO MONDAY WITH ENOUGH COLD AIR MOVING INTO THE AREA TO SUPPORT
WINTER PRECIPITATION. PRECIPITATION AMOUNTS MAY NOT BE TOO HIGH...
BUT WITH WINTER PRECIPITATION CHANCES SUNDAY AND MONDAY... MAY
HAVE SOME AREAS SLOWLY ACCUMULATE A COUPLE OF INCHES OF SNOW.
THERE IS ALSO SOME QUESTION IN THE MODELS ABOUT SUFFICIENT
HUMIDITY IN THE ICE CRYSTAL GROWTH LAYER AT TIMES TO KEEP FREEZING
RAIN IN THE DISCUSSION. RIGHT NOW WILL CONTINUE TO GO MOSTLY WITH
SNOW ALTHOUGH I HAVE MENTIONED FREEZING RAIN IN SOME AREAS ON
MONDAY. WILL CONTINUE TO WATCH TRENDS AS THIS DEVELOPS.
MOVING INTO MID-WEEK... FORECAST CONFIDENCE REMAINS LOW AS MEDIUM
RANGE MODELS DIFFER IN THE LOCATIONS OF THE LONGWAVE TROUGH IN THE
WEST AND THE WEAK RIDGE AHEAD OF IT SOMEWHERE IN THE ROCKIES OR
THE PLAINS. HOWEVER THERE IS REASONABLE AGREEMENT LATER IN THE
WEEK /JUST BEYOND THIS FORECAST PERIOD/ OF THE POTENTIAL OF MUCH
COLDER AIR SLIDING DOWN THE PLAINS.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 55 40 54 25 / 20 20 10 20
HOBART OK 64 39 54 27 / 10 0 0 10
WICHITA FALLS TX 71 46 59 31 / 10 0 0 10
GAGE OK 55 33 48 20 / 0 10 10 50
PONCA CITY OK 44 35 50 21 / 30 40 10 20
DURANT OK 58 51 61 32 / 40 30 20 10
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
84/06
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
140 PM CST FRI FEB 20 2015
.UPDATE...
FRONTAL BOUNDARY JUST NORTH OF THE CWA NOW...WITH A PREFRONTAL
AREA OF PRECIPITATION TRACKING OVER THE NORTHEAST. THE
PRECIPITATION HAS BEEN MOSTLY SNOW...BUT MAY BE A LITTLE FREEZING
PRECIPITATION MIXED IN AS WELL. ANOTHER AREA APPROACHING FROM THE
NORTHWEST...BUT SOME QUESTION AS TO WHETHER OR NOT COOLING WILL
HAVE BEGUN BEFORE IT GETS HERE. WILL LEAVE LIQUID PRECIPITATION
ACROSS THE WEST AND SNOW ACROSS THE EAST FOR NOW...BUT
ACCUMULATIONS SHOULD BE MINIMAL.
SEE UPDATED AVIATION DISCUSSION BELOW.
&&
.SHORT TERM...TODAY THROUGH SUNDAY
AS OF 9Z...A SURFACE LOW PRESSURE SYSTEM IS LOCATED OVER NORTHERN
NORTH DAKOTA. THE WARM FRONT ASSOCIATED WITH THE LOW PRESSURE IS
ALONG THE MISSOURI RIVER. THE WARM FRONT WILL PUSH EAST TODAY
ALLOWING FOR ABOVE NORMAL TEMPERATURES TO SPREAD ACROSS THE CWA.
THE PAST FEW RUNS OF THE HRRR AND RAPID REFRESH...PLUS THE NSSL
WRF ALL SUPPORT HIGHS IN THE MID 40S TO THE MID 50S FOR NORTH
CENTRAL AND CENTRAL SOUTH DAKOTA. COOLER TEMPERATURES ARE EXPECTED
IN NORTHEASTERN SOUTH DAKOTA AND WESTERN MINNESOTA.
A COLD FRONT...CURRENTLY OVER SOUTHERN CANADA...WILL SLIDE
SOUTHWARD ACROSS THE CWA LATER THIS AFTERNOON. LIGHT PRECIPITATION
IS POSSIBLE ALONG THIS FRONT...HOWEVER CHANCES APPEARS BETTER POST
FRONTAL...OR WITH THE CAA. PRECIPITATION AMOUNTS SHOULD BE RATHER
LIGHT. COLD AIR ADVECTION...THANKS TO AN ARCTIC HIGH
PRESSURE...WILL CONTINUE THROUGH SUNDAY WITH TEMPERATURES BECOMING
PROGRESSIVELY COLDER. HIGHS ON SATURDAY WILL RANGE FROM THE SINGLE
DIGITS...TO THE MID 20S. HIGHS BY SUNDAY WILL LIKELY RANGE FROM
THE SINGLE DIGITS BELOW ZERO...IN NORTHEASTERN SOUTH DAKOTA...TO
THE MID TEENS IN CENTRAL SOUTH DAKOTA.
.LONG TERM...SUNDAY NIGHT THROUGH THURSDAY
VERY GOOD AGREEMENT WITH ALL OF THE MODELS IN THE LONG TERM. THE
PERIOD BEGINS WITH ARCTIC HIGH PRESSURE CENTERED OVER EASTERN SD
BUILDING SOUTHEAST THROUGH SUNDAY NIGHT. AFTER A COLD SUNDAY
NIGHT...SOUTHWEST WINDS ON THE BACKSIDE OF THIS SURFACE HIGH WILL
BRING IN WARMER AIR WITH TEMPERATURES WARMING UP TO NEAR NORMAL BY
LATE MONDAY AFTERNOON. MONDAY NIGHT WILL BE MILD WITH PACIFIC AIR
MOVING ACROSS THE REGION ON WEST WINDS. TUESDAY WILL REMAIN NEAR
NORMAL FOR HIGHS WITH A TROUGH COMING THROUGH AS WINDS TURN
NORTHWEST AND INCREASE. AN ARCTIC BOUNDARY WILL THEN PUSH THROUGH
LATE TUESDAY AFTERNOON AND EVENING. ARCTIC AIR WILL REMAIN OVER
THE REGION THROUGH THURSDAY WITH MUCH BELOW NORMAL TEMPERATURES.
THE MODELS ALL SHOW A CLIPPER SYSTEM DROPPING SOUTHEAST ALONG THE
ARCTIC BOUNDARY LATE TUESDAY NIGHT THROUGH WEDNESDAY NIGHT. AT
THIS TIME THEY ALL SHOW SOME SNOW WITH THIS SYSTEM MAINLY ACROSS
THE WESTERN CWA. THUS...INCREASED POPS SOME AND MAY HAVE TO
INCREASE THEM MORE IN LATER FORECASTS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 138 PM CST FRI FEB 20 2015
A MIX OF VFR/MVFR CIGS ARE POSSIBLE FOR ALL TAF LOCATIONS...WITH A
TREND TOWARDS IFR...WHICH WILL LIKELY PERSIST THROUGH THE TAF
PERIOD. VSBY WILL BE PREDOMINANTLY VFR BUT CANT RULE OUT SOME
SHORT DURATION MVFR/IFR REDUCTIONS DUE TO SNOW. WINDS WILL SHIFT
FROM WEST/SOUTHWEST TO NORTHERLY AS WELL.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
UPDATE...PARKIN
SHORT TERM...SD
LONG TERM...MOHR
AVIATION...CONNELLY
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1141 AM CST FRI FEB 20 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 408 AM CST FRI FEB 20 2015
SNOWFALL WHICH HAS BEEN SCARCE SO FAR OVERNIGHT WILL GET ONE LAST
CHANCE THROUGH THE REMAINDER OF THE OVERNIGHT AS UPPER WAVE SHEARS
SOUTHEAST FROM NORTHEAST SOUTH DAKOTA INTO SOUTHERN MINNESOTA. WHILE
MARKEDLY BETTER CHANCE JUST NORTHEAST OF THE CWA...HAVE INCLUDED
SMALLER CHANCE POPS FOR THE REST OF THE OVERNIGHT TO COVER TIMING OF
WAVE. FOLLOWING THIS WAVE...OTHER THAN THE INCREASINGLY SHALLOW
LOWER LEVEL WARM ADVECTION...PRETTY MUCH SET UP FOR A PERIOD OF
FAIRLY LACKLUSTER FORCING BEHIND THIS WAVE THROUGH THE AFTERNOON...
WITH THE EVENTUAL NORTH-SOUTH SPLIT TO UPSTREAM SYSTEM PUSHING A
FRONTAL BOUNDARY INTO THE NORTHERN CWA DURING THE LATER AFTERNOON.
SEVERAL MODELS INDICATE THAT THERE WILL BE SOME LIGHT QPF NEAR THIS
BOUNDARY DURING THE LATER AFTERNOON...BUT MUCH OF THIS LOOKS TO BE A
RESULT OF SURFACE BASED DESTABILIZATION RATHER THAN ANY DYNAMICAL
LIFT FORCING WHICH REMAINS MINIMAL THROUGH THE DAY.
IT WILL BE SIGNIFICANTLY WARMER TODAY ACROSS THE AREA...WITH THE
GREATEST CHALLENGE TO THIS WARMING TO BE THE EXTENT OF CLOUDINESS
GIVEN A RELATIVE LACK OF SNOW COVER. BEHIND THE EARLY MORNING UPPER
WAVE...EXPECT MORE WIDESPREAD LOWER CLOUDINESS ACROSS CENTRAL NORTH
DAKOTA TO CONTINUE TO SURGE SOUTHEASTWARD...AS IS CURRENTLY UNDERWAY
IN NORTH CENTRAL SD. RAP SEEMS TO HAVE AN ADEQUATE HANDLE ON THE
SHORT TERM BEHAVIOR OF THE CLOUD FIELDS...AND HAVE GENERALLY USED AS
A GUIDE TO TRANSLATE THE LOWER CLOUDS SOUTH AND EAST THROUGH THE
DAY...HOLDING TOUGH MUCH OF THE DAY ACROSS SW MN AND INTO PARTS OF
NW IA. GIVEN TEMPS IN THE UPPER 20S TO AROUND 30 UNDER THE INCREASED
CLOUDS...AM HESITANT TO GO QUITE AS COOL AS SEVERAL SOLUTIONS
SUGGEST...AND HAVE BASED OFF A MODIFIED RAP SURFACE THERMAL FIELD
THROUGH THE DAY. THERE WILL AT LEAST BE A FAIR AMOUNT OF HIGHER
CLOUDS AROUND IN OTHER AREAS SOUTHWEST OF THE LOWER CLOUDS...WHERE
WHICH IT WILL LIKELY PUSH 50 DEGREES ON MIXING ALONE IN THE WESTERN
MISSOURI VALLEY...AND EVEN A MODEST RIDE INTO THE LOWER 30S EXPECTED
IN SW MN.
LOWER LEVEL COLD AIR WILL BEGIN TO SURGE SOUTHWARD...ESPECIALLY
THROUGH THE LATTER HALF OF THE NIGHT...WITH FAIRLY STRONG
ISALLOBARIC RISES SET TO DRIVE AN INCREASING NORTHERLY WIND THROUGH
THE NIGHT. THIS TYPE OF SET UP ALMOST ALWAYS HAS THE COOLING COMING
IN A MORE FORCEFUL WAY...AND HAVE PUSHED THE COOLING RATES UP ABOUT
3 HOURS LATER TONIGHT AND EARLY SATURDAY MORNING THAN EVEN SOME OF
THE COOLER RAW GUIDANCE. GRADUALLY...THERMAL FIELDS BECOME MORE
FAVORABLE FOR SHALLOW FORCED PRECIPITATION BEHIND THE FRONTAL
BOUNDARY. AT THIS TIME...HAVE PRECLUDED ANY MENTION OF MEASURABLE
SNOWFALL /OR POTENTIALLY RAINFALL EARLY EVENING IN THE WEST/...BUT
DID WORK IN A GRADUAL NORTH TO SOUTH SPREAD FOR ISOLATED TO
SCATTERED FLURRIES. WIND CHILLS BY MORNING WILL RETURN BELOW ZERO
FROM EAST CENTRAL SD THROUGH MUCH OF SW MN.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 408 AM CST FRI FEB 20 2015
FOR THE WEEKEND...THE FORECAST CONCERN CENTERS ON THE ARCTIC AIR
MOVING IN. THE COLD AIR BEHIND THE FRONT THAT MOVES THROUGH
TONIGHT WILL CONTINUE TO SURGE SOUTHWARD ON SATURDAY. AS A RESULT
EXPECT TEMPERATURES TO BASICALLY BE STEADY OR SLOWLY FALL THROUGH
THE DAY WITH HIGHS LIKELY TO BE AROUND SUNRISE. BY EVENING
TEMPERATURES WILL RANGE FROM THE SINGLE DIGITS ABOVE ZERO NORTH OF
I90 TO THE LOWER 20S IN THE MISSOURI VALLEY. NORTHWEST WINDS WILL
BE GUSTING AS HIGH AS 30 MPH BEHIND THE FRONT AND THIS WILL
PRODUCE WIND CHILLS BELOW ZERO NORTH OF AND EAST OF THE JAMES AND
MISSOURI VALLEY THROUGHOUT THE DAY.
NORTHWEST WINDS ARE EXPECTED TO REMAIN BETWEEN 10 AND 20 MPH
SATURDAY NIGHT AND MUCH OF SUNDAY. WITH LOWS EXPECTED TO BE AT OR
BELOW ZERO IN ALL BUT THE MISSOURI VALLEY SATURDAY NIGHT...WIND
CHILLS WILL RANGE FROM -15 TO -30 LATE SATURDAY NIGHT AND SUNDAY
MORNING WITH THE COLDEST WIND CHILLS IN SOUTHWEST MINNESOTA.
DESPITE SUNSHINE AND LITTLE SNOW COVER...HIGHS SUNDAY WILL
GENERALLY BE IN THE SINGLE DIGITS ABOVE ZERO. HIGH PRESSURE WILL
MOVE FROM MINNESOTA INTO WESTERN ILLINOIS ON SUNDAY NIGHT. WINDS
WILL DECREASE FAIRLY RAPIDLY AFTER DARK AND THEN AS THE HIGH MOVES
THROUGH IOWA...TURN TO THE SOUTH AND BEGIN TO
INCREASE...ESPECIALLY WEST OF I29. WITH CLEAR SKIES AND LIGHT
WINDS...MOST LOCATIONS WILL FALL IN THE EVENING BUT TEMPERATURES
WILL BECOME STEADY OR EVEN RISE A FEW DEGREES AFTER MIDNIGHT. AS A
RESULT...LOWS WILL BE IN THE SINGLE DIGITS BELOW ZERO EAST OF THE
JAMES RIVER AND IN THE SINGLE DIGITS ABOVE ZERO WEST OF THE JAMES
RIVER.
IN THE EXTENDED...MONDAY THROUGH THURSDAY...IT WILL BE A CONTRAST
IN REGIMES...WITH NEAR NORMAL TO ABOVE NORMAL TEMPERATURES MONDAY
AND TUESDAY AND BELOW NORMAL TEMPERATURES WEDNESDAY AND THURSDAY
AS ANOTHER SURGE OF ARCTIC AIR MOVES INTO THE AREA. THERE IS
SURPRISINGLY LITTLE DIFFERENCE IN THE OVERALL PATTERN BETWEEN THE
ECMWF...GFS AND THE GFS ENSEMBLE. SO CONFIDENCE IS HIGH IN TERMS
OF THE TEMPERATURE TRENDS. THE ONLY UNCERTAINTY RESTS WITH THE
CHANCE OF SNOW ON WEDNESDAY AND WEDNESDAY NIGHT. THE ECMWF IS
WEAKER WITH THE SNOWFALL...BASICALLY EXTENDING FROM WESTERN NORTH
DAKOTA...THROUGH MUCH OF SOUTH DAKOTA...AND INTO EASTERN NEBRASKA
AND FAR WESTERN IOWA. THE GFS IS GENERALLY IN THE SAME AREA BUT
FASTER AND WITH MORE SNOWFALL. WITH AN ARCTIC AIR MASS IN
PLACES...MOISTURE WILL BE LIMITED SO A SOLUTION CLOSER TO THE
ECMWF SEEMS MORE LIKELY AT THIS POINT.
ON MONDAY WILL SEE A GRADUAL WARMING AS WINDS INCREASE OUT OF THE
SOUTHWEST. BY AFTERNOON IT COULD BECOME QUITE BREEZY AND WITH
SKIES EXPECTED TO BE PARTLY TO MOSTLY SUNNY...THE ATMOSPHERE
SHOULD BECOME MORE MIXED THROUGH THE DAY. AS A RESULT...EXPECT TO
SEE QUITE A DIURNAL RANGE WITH HIGHS WARMING 25 TO 30 DEGREES INTO
THE MID 20S TO MID 30S. WITH WEST TO NORTHWEST FLOW CONTINUING
MONDAY NIGHT...EXPECT TEMPERATURES TO REMAIN IN THE 20S. TUESDAY
WILL SEE THE PASSAGE OF THE NEXT ARCTIC FRONT. WITH STRONG
NORTHWEST WINDS BEHIND THE FRONT...EXPECT THE AIR ALOFT TO MIX TO
THE SURFACE HELPING TEMPERATURES TO RISE BACK ABOVE FREEZING
BEFORE THE REAL COLD AIR MOVES BACK IN TUESDAY NIGHT. HIGHS
WEDNESDAY WILL BE IN THE TEENS AND 20S WITH EVEN COLDER
TEMPERATURES EXPECTED THURSDAY. WITH THE COLD AIR IN CANADA WOULD
NOT BE SURPRISED IF THIS AIR MASS ENDS UP A FEW DEGREES COLDER
THAN FORECAST BUT WILL WAIT UNTIL THERE IS MORE CONFIDENCE IN THE
MAGNITUDE OF THE COLD AIR BEFORE LOWERING TEMPERATURES EVEN MORE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1141 AM CST FRI FEB 20 2015
MVFR CEILINGS WILL ERODE OVER THE I 29 CORRIDOR THROUGH THE
AFTERNOON HOURS. THESE CEILINGS ARE CURRENTLY AFFECTING THE KFSD
TAF SITE. THERE ARE NO VISIBILITY RESTRICTIONS. TONIGHT...ANOTHER
ARCTIC COLD FRONT WILL MOVE SOUTHWARD...WITH BOTH THE NAM AND GFS
SHOWING STRATUS COMING DOWN BEHIND THE FRONT. THEREFORE KEPT THE
MVFR MENTION GOING IN THE TAF SITES.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
SHORT TERM...CHAPMAN
LONG TERM...SCHUMACHER
AVIATION...MJ
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
1130 AM CST FRI FEB 20 2015
.UPDATE...
FRONTAL BOUNDARY JUST NORTH OF THE CWA NOW...WITH A PREFRONTAL
AREA OF PRECIPITATION TRACKING OVER THE NORTHEAST. THE
PRECIPITATION HAS BEEN MOSTLY SNOW...BUT MAY BE A LITTLE FREEZING
PRECIPITATION MIXED IN AS WELL. ANOTHER AREA APPROACHING FROM THE
NORTHWEST...BUT SOME QUESTION AS TO WHETHER OR NOT COOLING WILL
HAVE BEGUN BEFORE IT GETS HERE. WILL LEAVE LIQUID PRECIPITATION
ACROSS THE WEST AND SNOW ACROSS THE EAST FOR NOW...BUT
ACCUMULATIONS SHOULD BE MINIMAL.
SEE UPDATED AVIATION DISCUSSION BELOW.
&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TODAY THROUGH SUNDAY
AS OF 9Z...A SURFACE LOW PRESSURE SYSTEM IS LOCATED OVER NORTHERN
NORTH DAKOTA. THE WARM FRONT ASSOCIATED WITH THE LOW PRESSURE IS
ALONG THE MISSOURI RIVER. THE WARM FRONT WILL PUSH EAST TODAY
ALLOWING FOR ABOVE NORMAL TEMPERATURES TO SPREAD ACROSS THE CWA.
THE PAST FEW RUNS OF THE HRRR AND RAPID REFRESH...PLUS THE NSSL
WRF ALL SUPPORT HIGHS IN THE MID 40S TO THE MID 50S FOR NORTH
CENTRAL AND CENTRAL SOUTH DAKOTA. COOLER TEMPERATURES ARE EXPECTED
IN NORTHEASTERN SOUTH DAKOTA AND WESTERN MINNESOTA.
A COLD FRONT...CURRENTLY OVER SOUTHERN CANADA...WILL SLIDE
SOUTHWARD ACROSS THE CWA LATER THIS AFTERNOON. LIGHT PRECIPITATION
IS POSSIBLE ALONG THIS FRONT...HOWEVER CHANCES APPEARS BETTER POST
FRONTAL...OR WITH THE CAA. PRECIPITATION AMOUNTS SHOULD BE RATHER
LIGHT. COLD AIR ADVECTION...THANKS TO AN ARCTIC HIGH
PRESSURE...WILL CONTINUE THROUGH SUNDAY WITH TEMPERATURES BECOMING
PROGRESSIVELY COLDER. HIGHS ON SATURDAY WILL RANGE FROM THE SINGLE
DIGITS...TO THE MID 20S. HIGHS BY SUNDAY WILL LIKELY RANGE FROM
THE SINGLE DIGITS BELOW ZERO...IN NORTHEASTERN SOUTH DAKOTA...TO
THE MID TEENS IN CENTRAL SOUTH DAKOTA.
.LONG TERM...SUNDAY NIGHT THROUGH THURSDAY
VERY GOOD AGREEMENT WITH ALL OF THE MODELS IN THE LONG TERM. THE
PERIOD BEGINS WITH ARCTIC HIGH PRESSURE CENTERED OVER EASTERN SD
BUILDING SOUTHEAST THROUGH SUNDAY NIGHT. AFTER A COLD SUNDAY
NIGHT...SOUTHWEST WINDS ON THE BACKSIDE OF THIS SURFACE HIGH WILL
BRING IN WARMER AIR WITH TEMPERATURES WARMING UP TO NEAR NORMAL BY
LATE MONDAY AFTERNOON. MONDAY NIGHT WILL BE MILD WITH PACIFIC AIR
MOVING ACROSS THE REGION ON WEST WINDS. TUESDAY WILL REMAIN NEAR
NORMAL FOR HIGHS WITH A TROUGH COMING THROUGH AS WINDS TURN
NORTHWEST AND INCREASE. AN ARCTIC BOUNDARY WILL THEN PUSH THROUGH
LATE TUESDAY AFTERNOON AND EVENING. ARCTIC AIR WILL REMAIN OVER
THE REGION THROUGH THURSDAY WITH MUCH BELOW NORMAL TEMPERATURES.
THE MODELS ALL SHOW A CLIPPER SYSTEM DROPPING SOUTHEAST ALONG THE
ARCTIC BOUNDARY LATE TUESDAY NIGHT THROUGH WEDNESDAY NIGHT. AT
THIS TIME THEY ALL SHOW SOME SNOW WITH THIS SYSTEM MAINLY ACROSS
THE WESTERN CWA. THUS...INCREASED POPS SOME AND MAY HAVE TO
INCREASE THEM MORE IN LATER FORECASTS.
&&
.AVIATION...
18Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
A MIX OF VFR/MVFR CIGS ARE POSSIBLE FOR ALL TAF LOCATIONS...WITH A
TREND TOWARDS IFR...WHICH WILL LIKELY PERSIST THROUGH THE TAF
PERIOD. VSBY WILL BE PREDOMINANTLY VFR BUT CANT RULE OUT SOME
SHORT DURATION MVFR/IFR REDUCTIONS DUE TO SNOW. WINDS WILL SHIFT
FROM WEST/SOUTHWEST TO NORTHERLY AS WELL.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
UPDATE...PARKIN
SHORT TERM...SD
LONG TERM...MOHR
AVIATION...CONNELLY
WEATHER.GOV/ABERDEEN