Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 01/21/16
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
301 PM MST TUE JAN 19 2016
.SYNOPSIS...
A WEAK LOW PRESSURE SYSTEM WILL BRING A CHANCE OF LIGHT PRECIPITATION
TO MAINLY NORTHERN ARIZONA TONIGHT. HIGH PRESSURE WILL BUILD ACROSS
THE DESERT SOUTHWEST WEDNESDAY CONTINUING INTO THE WEEKEND.
TEMPERATURES A FEW DEGREES ABOVE NORMAL ARE EXPECTED BY LATE IN THE
WEEK.
&&
.DISCUSSION...
MID AND HIGH CLOUDS CONTINUE TO BE ON THE INCREASE AHEAD OF A FAST-
MOVING LOW PRESSURE SYSTEM AFFECTING THE CA COAST. LATEST MRMS SHOWS
A WIDESPREAD AREA OF LIGHT SHOWER ACTIVITY SLIDING EASTWARD THROUGH
CENTRAL AND SOUTHERN CA. HI-RES WRFS INCLUDING THE HRRR CONTINUE TO
INDICATE A BRIEF OPPORTUNITY FOR LIGHT PRECIPITATION
OVERNIGHT...MAINLY ACROSS NORTHERN AND CENTRAL AZ. LATEST NCAR
ENSEMBLE SUGGESTS A LIGHT SHOWER IS EVEN POSSIBLE ACROSS THE PHOENIX
AREA. HOWEVER...PROBABILITIES GENERALLY REMAIN LESS THAN 10
PERCENT...EXCEPT ACROSS THE HIGHER TERRAIN OF SOUTHERN GILA COUNTY.
STRONG SUBSIDENCE AND A RAPID CLEARING TREND WILL THEN TAKE PLACE
DURING THE PRE-DAWN HOURS. LOW TEMPERATURES OVERNIGHT WILL BE NEAR
NORMAL.
&&
.PREVIOUS DISCUSSION...
RIDGING WILL BUILD INTO THE DESERT SOUTHWEST BEHIND THIS TROUGH ON
WEDNESDAY AND REMAIN IN PLACE THROUGH AT LEAST SATURDAY. SATURDAY
NIGHT WILL SEE THE TAIL END OF A WEAK TROUGH MOVE THROUGH SOUTHERN
CALIFORNIA AND ARIZONA. HOWEVER...A NEGLIGIBLE INCREASE IN PRE-
FRONTAL MOISTURE AND LITTLE TO NO NOTEWORTHY ISENTROPIC ASCENT WILL
PRECLUDE WIDESPREAD PRECIP DEVELOPMENT ACROSS THE AREA. NAEFS STILL
MAINTAINS 10 POPS EAST OF PHOENIX AND THIS SEEMS
REASONABLE...OTHERWISE SINGLE DIGIT POPS APPEAR TO BE ALL THAT IS
WARRANTED. WEAK RIDGING WILL RETURN EARLY NEXT WEEK.
AS FOR TEMPERATURES...EXPECT BOTH HIGHS AND LOWS TO BE WITHIN A FEW
DEGREES OF NORMAL THROUGH SATURDAY. WEAK POST-FRONTAL COLD ADVECTION
COULD KNOCK TEMPS BACK INTO THE LOW/MID 60S SUNDAY AND MONDAY BUT
ASIDE FROM THAT...NO MAJOR DEPARTURES FROM NORMAL ARE EXPECTED AT ANY
TIME OVER THE NEXT WEEK.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...KSDL...AND
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
A WEAK DISTURBANCE WILL WORK IT`S WAY INTO SE CALIFORNIA TODAY AND
THEN INTO ARIZONA DURING THE LATE AFTERNOON AND TONIGHT. THIS WILL
BRING THE NEXT ROUND OF HIGH TO MID CLOUD CIGS OVER THE SE
CALIFORNIA TAF SITES THIS MORNING AND THEN INTO THE PHX VALLEY TAF
SITES BY LATE AFTERNOON AND THROUGH TONIGHT. EXPECT WINDS TO REMAIN
LIGHT TO OCCASIONALLY LIGHT AND VARIABLE AND GENERALLY FAVOR
FAMILIAR DIURNAL PATTERNS ALONG WITH GOOD VISIBILITIES THROUGHOUT
THE PERIOD.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
THURSDAY THROUGH MONDAY...
A HIGH PRESSURE RIDGE WILL DOMINATE THE AREA THURSDAY AND FRIDAY
BRINGING A SLIGHT WARMING TREND WITH SLIGHTLY ABOVE NORMAL HIGH
TEMPERATURES THROUGH FRIDAY. THEN THE NEXT WEAK SYSTEMS MOVE THROUGH
FRIDAY NIGHT/SATURDAY MORNING AND SUNDAY HELPING TO BRING HIGH
TEMPERATURES BACK TO NEAR NORMAL ON SATURDAY AND SLIGHTLY BELOW
NORMAL SUNDAY ALONG WITH VERY LITTLE CHANCE OF RAIN. EXPECT WINDS TO
BE GENERALLY LIGHT AND FOLLOW USUAL DIURNAL TENDENCIES WITH SOME
AFTERNOON WESTERLY AND NORTHWESTERLY BREEZES ON SUNDAY AFTERNOON IN
SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA WITH WIND GUSTS OF ABOUT
15 TO 22 KNOTS. MINIMUM HUMIDITIES WILL RANGE FROM THE MID/UPPER
TEENS TO THE LOW/MID 20S PERCENT RANGE ON ALL DAYS EXCEPT FOR SUNDAY
WHEN THEY WILL TEMPORARILY BUMP UP TO THE UPPER 20S TO MID 30S
PERCENT RANGE. EXPECT GOOD TO EXCELLENT OVERNIGHT RECOVERIES.
&&
.SPOTTER INFORMATION STATEMENT...
SPOTTERS ARE ENCOURAGED TO REPORT BASED ON STANDARD OPERATING
PROCEDURES.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...HIRSCH
PREVIOUS DISCUSSION...LEINS
AVIATION...SAWTELLE
FIRE WEATHER...SAWTELLE
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
1011 AM PST TUE JAN 19 2016
.SYNOPSIS...RAIN THIS MORNING...HEAVY AT TIMES BEFORE TURNING TO
SHOWERS FOR THE MIDDAY AND EARLY AFTERNOON HOURS. HIGH PRESSURE
BUILDS TONIGHT THROUGH THURSDAY WITH A PERIOD OF DRY AND
SEASONABLY MILD WEATHER. NEXT FRONT ARRIVES THURSDAY NIGHT INTO
FRIDAY WITH A PERIOD OF LIGHT RAIN...POSSIBLY BECOMING HEAVY FOR A
TIME FRIDAY NIGHT WHEN THE UPPER LOW PASSES OVERHEAD WITH
LINGERING SHOWERS SATURDAY. LATEST INDICATIONS SHOW A RETURN OF
DRY WEATHER SUNDAY THROUGH THE MIDDLE OF NEXT WEEK.
&&
.DISCUSSION...AS OF 09:50 AM PST TUESDAY...THE MAIN RAIN BAND
PRODUCING MODERATE TO HEAVY RAIN CONTINUES TO SHIFT SOUTHWARD
THROUGH THE SOUTH BAY AND MONTEREY BAY REGION AT THIS HOUR.
RAINFALL RATES HAVE BEEN UPWARD OF 3/4" PER HOUR IN THE COASTAL
RANGES WITH 1/10" TO 1/4" FOR URBAN AREAS. FURTHER NORTH AND BACK
BEHIND THE BOUNDARY, ISOLATED TO SCATTERED SHOWERS WILL REMAIN
POSSIBLE THROUGH THE MORNING. OVERALL, EXPECTING CONDITIONS TO
CLEAR FROM NORTH TO SOUTH THROUGH THE AFTERNOON. UPDATED SHORT-
TERM FORECAST HAS BEEN SENT. PLEASE SEE PREVIOUS DISCUSSION FOR
MORE DETAILS ON THE EXTENDED FORECAST PERIOD.
&&
.PREV DISCUSSION...AS OF 3:52 AM PST TUESDAY...INITIAL RAIN BAND
IS MOVING ONSHORE AS OF THIS WRITING...MAINLY ARRIVING FROM THE
WEST WITH RAIN DEVELOPING OVER MOST OF THE DISTRICT. AMOUNTS SO
FAR HAVE BEEN LIGHT BUT THAT SHOULD CHANGE QUICKLY OVER THE NEXT
SEVERAL HOURS THAT WILL ENCOMPASS THE MORNING COMMUTE. SATELLITE
IMAGERY SHOWS RAPIDLY COOLING CLOUD TOPS OFFSHORE WITH INCOMING
JET STREAK AND ASSOCIATED SHORTWAVE. AMSU TPW SHOWS GOOD MOISTURE
TAP BUT BEST PLUME OF 1.5 TPW MAY STAY JUST OFFSHORE. LATEST
OBSERVED TRENDS SUGGESTS THAT SOME OF THE HEAVIEST RAIN MAY NOW
SHIFT SLIGHTLY SOUTHWARD AND IMPACT THE SANTA CRUZ MTNS AND SANTA
LUCIA RANGE ABOVE BIG SUR. THE HRRR AND RAP MESOSCALE/SHORT TERM
MODELS SHOW 3-4 INCHES FOR THE SANTA CRUZ MTNS WITH SOME OF THE
HRRR RUNS IN EXCESS OF 7 INCHES ABOVE BIG SUR...ALL OCCURRING OVER
THE NEXT 8-10 HOURS. WILL BE WATCHING RAIN RATES AND TRENDS
CLOSELY THE NEXT FEW HOURS FOR POSSIBLE URBAN AND SMALL STREAM
FLOOD ADVISORIES THROUGHOUT THE BAY AREA...WITH POSSIBILITY THAT
WARNINGS COULD BE NEEDED FOR THE HILLS ABOVE BIG SUR. UPSHOT IS
THAT THE COMMUTE WILL QUICKLY TURN UGLY FOR THE BAY AREA WITH
HEAVIEST RAINS FROM NOW THROUGH ROUGHLY 18-20Z. SIMILAR TO
YESTERDAYS STORM THE STEADY RAIN SHOULD END ABRUPTLY AROUND MIDDAY
IN THE BAY AREA WHILE HANGING ON LONGER FOR THE CENTRAL COAST.
SHOWERS THIS AFTERNOON BUT EVEN THOSE WILL BE LIMITED WITH SOME
LATE DAY PEAKS OF SUNSHINE. WINDS WITH TODAYS FRONT WILL BE
SOUTHERLY THIS MORNING....STRONGEST ON THE COAST AND OVER THE
OCEAN WITH GUSTS AROUND 30 MPH. WINDS TURN WEST BY MIDDAY BUT
GIVEN THE LACK OF COLD ADVECTION THE WESTERLY WINDS WONT BE TOO
STRONG.
HAVE REMOVED ALL CHANCES OF RAIN FOR THIS EVENING AS THE SYSTEM
WILL QUICKLY MOVE EASTWARD. HIGH PRESSURE BUILDS IN TONIGHT AND
LASTS THROUGH THURSDAY. AIRMASS IS MILD AND EXPECT DAYTIME HIGHS
TO BE COMFORTABLY IN THE 60S MIDWEEK WITH MILD OVERNIGHT LOWS
GENERALLY IN THE 40S.
NEXT FRONT ARRIVES THURSDAY NIGHT. INITIAL BOUNDARY DOESN`T LOOK
TOO IMPRESSIVE WITH SOUTHERLY WINDS NOT-FAVORABLE FOR OROGRAPHICS.
GFS AND ECMWF BOTH SHOW FAIRLY WEAK FRONT MOVING THROUGH TIL
MIDDAY FRIDAY...THEN COLD UPPER TROUGH SHOULD PASS OVER THE REGION
AND ALLOW FOR AN UPTICK IN RAIN SHOWERS AND INTENSITY WITH SHOWERS
LASTING INTO SATURDAY. STILL SEVERAL DAYS OUT SO THAT WILL BECOME
THE FOCUS AFTER TODAYS EVENT.
LATEST MODEL TREND OVER THE LAST 24 HOURS HAS BEEN TO BUILD HIGH
PRESSURE SATURDAY NIGHT THROUGH THE MIDDLE OF NEXT WEEK. IN
COORDINATION WITH WFO EUREKA REMOVED NEARLY ALL RAIN CHANCES FOR
THE NORTH BAY AS WELL AS THE REST OF THE DISTRICT AFTER SATURDAY
NIGHT.
HOWEVER MUST POINT OUT THE LONG RANGE GFS CONTINUES TO SHOW
ANOTHER COLD WEST COAST TROUGH AND ASSOCIATED RAIN ARRIVING
SOMETIME AROUND JAN 29TH WITH EXTENDED GFS AND CFS MODELS KEEPING
PATTERN ACTIVE.
&&
.AVIATION...AS OF 10:00 AM PST TUESDAY...DYNAMIC
FORECAST...ESPECIALLY IN THE SHORT TERM...AS A COLD FRONT MOVES
THROUGH. THE FRONT LOOKS BE BE ENTERING THE N BAY WITH A WIND
SHIFT ALREADY SHOWING UP THE ON BUOYS. THE HEAVIEST RAIN HAS
ALREADY MOVED THROUGH SFO/OAK/STS. WINDS WILL REMAIN GUSTY
THROUGH THE MORNING. DO EXPECT CONDITIONS TO BE IMPROVING AT ALL
SITE BY THIS AFTERNOON. THE REAL QUESTION/UNCERTAINTY WILL BE HOW
MUCH CLEARING OCCURS. VIS SATELLITE SHOWS A LOT OF CLEARING TO THE
WEST...BUT RESIDUAL MOISTURE AND DAYTIME HEATING MAY ACTUALLY
LIMIT THIS. AS FOR TONIGHT...RESIDUAL MOISTURE AND COOLING WILL
LIKELY LEAD TO LOW CLOUDS AND POSS FOG. WILL DEFINITELY HAVE TO
WATCH FOR RAPID DEVELOPMENT OF ANY DENSE FOG. CONF IS MEDIUM FOR
THE ENTIRE FORECAST.
VICINITY OF KSFO...LIGHT RAIN CONTINUES...BUT HEAVIEST HAS ENDED.
VIS WILL REMAIN LOW WITH CIGS IN THE MVFR RANGE. AS FOR
WINDS...THE SHIFT TO SW HAS ALREADY OCCURRED AND WILL REMAIN THERE
FOR THE DAY. WIND SPEEDS HAVE PEAKED...BUT WILL REMAIN GUSTY. WILL
KEEP LINGERING CLOUDS THROUGH THE DAY GIVEN THE AMOUNT OF LOW
LEVEL MOISTURE.
SFO BRIDGE APPROACH...SIMILAR TO KSFO.
MONTEREY BAY AREA TERMINALS...MODERATE TO HEAVY RAIN OVER THE NEXT
FEW HOURS WITH REDUCED VIS AND LOWERED CIGS. IMPROVEMENT EXPECTED
AFTER 20Z THIS AFTERNOON. CIGS AND FOG RETURN TONIGHT...POSS DENSE
FOG.
&&
.MARINE...AS OF 09:58 AM PST TUESDAY...STRONG AND GUSTY WINDS WILL
PREVAIL TODAY AS A STORM SYSTEM PASSING THROUGH THE REGION. WINDS
WILL DECREASE RAPIDLY THIS EVENING AFTER THE STORM PASSES. ANOTHER
STORM WILL BRING INCREASING WINDS AGAIN BY FRIDAY. A LONG PERIOD
LARGE SWELL IS FORECAST TO IMPACT THE REGION LATER THIS WEEK.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.TDAY...SCA...SF BAY UNTIL 3 PM
SCA...PT ARENA TO PT REYES 0-10 NM UNTIL 3 PM
SCA...PT REYES TO PIGEON PT 0-10 NM UNTIL 3 PM
SCA...PIGEON PT TO PT PINOS 0-10 NM UNTIL 3 PM
SCA...PT PINOS TO PT PIEDRAS BLANCAS 0-10 NM UNTIL 3 PM
SCA...PT ARENA TO PIGEON PT 10-60 NM UNTIL 3 PM
SCA...PIGEON PT TO PT PIEDRAS BLANCAS 10-60 NM UNTIL 3 PM
SCA...ROUGH BAR ADVISORY FOR SF BAR UNTIL 3 PM
&&
$$
PUBLIC FORECAST: RGASS
AVIATION: MM
MARINE: MM
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AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
954 AM PST TUE JAN 19 2016
.SYNOPSIS...RAIN THIS MORNING...HEAVY AT TIMES BEFORE TURNING TO
SHOWERS FOR THE MIDDAY AND EARLY AFTERNOON HOURS. HIGH PRESSURE
BUILDS TONIGHT THROUGH THURSDAY WITH A PERIOD OF DRY AND
SEASONABLY MILD WEATHER. NEXT FRONT ARRIVES THURSDAY NIGHT INTO
FRIDAY WITH A PERIOD OF LIGHT RAIN...POSSIBLY BECOMING HEAVY FOR A
TIME FRIDAY NIGHT WHEN THE UPPER LOW PASSES OVERHEAD WITH
LINGERING SHOWERS SATURDAY. LATEST INDICATIONS SHOW A RETURN OF
DRY WEATHER SUNDAY THROUGH THE MIDDLE OF NEXT WEEK.
&&
.DISCUSSION...AS OF 09:50 AM PST TUESDAY...THE MAIN RAIN BAND
PRODUCING MODERATE TO HEAVY RAIN CONTINUES TO SHIFT SOUTHWARD
THROUGH THE SOUTH BAY AND MONTEREY BAY REGION AT THIS HOUR.
RAINFALL RATES HAVE BEEN UPWARD OF 3/4" PER HOUR IN THE COASTAL
RANGES WITH 1/10" TO 1/4" FOR URBAN AREAS. FURTHER NORTH AND BACK
BEHIND THE BOUNDARY, ISOLATED TO SCATTERED SHOWERS WILL REMAIN
POSSIBLE THROUGH THE MORNING. OVERALL, EXPECTING CONDITIONS TO
CLEAR FROM NORTH TO SOUTH THROUGH THE AFTERNOON. UPDATED SHORT-
TERM FORECAST HAS BEEN SENT. PLEASE SEE PREVIOUS DISCUSSION FOR
MORE DETAILS ON THE EXTENDED FORECAST PERIOD.
&&
.PREV DISCUSSION...AS OF 3:52 AM PST TUESDAY...INITIAL RAIN BAND
IS MOVING ONSHORE AS OF THIS WRITING...MAINLY ARRIVING FROM THE
WEST WITH RAIN DEVELOPING OVER MOST OF THE DISTRICT. AMOUNTS SO
FAR HAVE BEEN LIGHT BUT THAT SHOULD CHANGE QUICKLY OVER THE NEXT
SEVERAL HOURS THAT WILL ENCOMPASS THE MORNING COMMUTE. SATELLITE
IMAGERY SHOWS RAPIDLY COOLING CLOUD TOPS OFFSHORE WITH INCOMING
JET STREAK AND ASSOCIATED SHORTWAVE. AMSU TPW SHOWS GOOD MOISTURE
TAP BUT BEST PLUME OF 1.5 TPW MAY STAY JUST OFFSHORE. LATEST
OBSERVED TRENDS SUGGESTS THAT SOME OF THE HEAVIEST RAIN MAY NOW
SHIFT SLIGHTLY SOUTHWARD AND IMPACT THE SANTA CRUZ MTNS AND SANTA
LUCIA RANGE ABOVE BIG SUR. THE HRRR AND RAP MESOSCALE/SHORT TERM
MODELS SHOW 3-4 INCHES FOR THE SANTA CRUZ MTNS WITH SOME OF THE
HRRR RUNS IN EXCESS OF 7 INCHES ABOVE BIG SUR...ALL OCCURRING OVER
THE NEXT 8-10 HOURS. WILL BE WATCHING RAIN RATES AND TRENDS
CLOSELY THE NEXT FEW HOURS FOR POSSIBLE URBAN AND SMALL STREAM
FLOOD ADVISORIES THROUGHOUT THE BAY AREA...WITH POSSIBILITY THAT
WARNINGS COULD BE NEEDED FOR THE HILLS ABOVE BIG SUR. UPSHOT IS
THAT THE COMMUTE WILL QUICKLY TURN UGLY FOR THE BAY AREA WITH
HEAVIEST RAINS FROM NOW THROUGH ROUGHLY 18-20Z. SIMILAR TO
YESTERDAYS STORM THE STEADY RAIN SHOULD END ABRUPTLY AROUND MIDDAY
IN THE BAY AREA WHILE HANGING ON LONGER FOR THE CENTRAL COAST.
SHOWERS THIS AFTERNOON BUT EVEN THOSE WILL BE LIMITED WITH SOME
LATE DAY PEAKS OF SUNSHINE. WINDS WITH TODAYS FRONT WILL BE
SOUTHERLY THIS MORNING....STRONGEST ON THE COAST AND OVER THE
OCEAN WITH GUSTS AROUND 30 MPH. WINDS TURN WEST BY MIDDAY BUT
GIVEN THE LACK OF COLD ADVECTION THE WESTERLY WINDS WONT BE TOO
STRONG.
HAVE REMOVED ALL CHANCES OF RAIN FOR THIS EVENING AS THE SYSTEM
WILL QUICKLY MOVE EASTWARD. HIGH PRESSURE BUILDS IN TONIGHT AND
LASTS THROUGH THURSDAY. AIRMASS IS MILD AND EXPECT DAYTIME HIGHS
TO BE COMFORTABLY IN THE 60S MIDWEEK WITH MILD OVERNIGHT LOWS
GENERALLY IN THE 40S.
NEXT FRONT ARRIVES THURSDAY NIGHT. INITIAL BOUNDARY DOESN`T LOOK
TOO IMPRESSIVE WITH SOUTHERLY WINDS NOT-FAVORABLE FOR OROGRAPHICS.
GFS AND ECMWF BOTH SHOW FAIRLY WEAK FRONT MOVING THROUGH TIL
MIDDAY FRIDAY...THEN COLD UPPER TROUGH SHOULD PASS OVER THE REGION
AND ALLOW FOR AN UPTICK IN RAIN SHOWERS AND INTENSITY WITH SHOWERS
LASTING INTO SATURDAY. STILL SEVERAL DAYS OUT SO THAT WILL BECOME
THE FOCUS AFTER TODAYS EVENT.
LATEST MODEL TREND OVER THE LAST 24 HOURS HAS BEEN TO BUILD HIGH
PRESSURE SATURDAY NIGHT THROUGH THE MIDDLE OF NEXT WEEK. IN
COORDINATION WITH WFO EUREKA REMOVED NEARLY ALL RAIN CHANCES FOR
THE NORTH BAY AS WELL AS THE REST OF THE DISTRICT AFTER SATURDAY
NIGHT.
HOWEVER MUST POINT OUT THE LONG RANGE GFS CONTINUES TO SHOW
ANOTHER COLD WEST COAST TROUGH AND ASSOCIATED RAIN ARRIVING
SOMETIME AROUND JAN 29TH WITH EXTENDED GFS AND CFS MODELS KEEPING
PATTERN ACTIVE.
&&
.AVIATION...AS OF 9:45 PM PST MONDAY...CLOUDS WILL LOWER AND
BECOMING MORE WIDESPREAD OVERNIGHT AS THE NEXT WEATHER SYSTEM
APPROACHES THE COAST. LOOK FOR MVFR CIGS AND RAIN TO SPREAD FROM
NORTH TO SOUTH BETWEEN 08Z AND 14Z. SOUTH TO SOUTHEAST WINDS WILL
ALSO INCREASE IN THIS TIME PERIOD. A PERIOD OF STRONGER
WINDS...MORE INTENSE PRECIP...AND LOWER CIGS IS LIKELY JUST AHEAD
OF THE FRONT BETWEEN 15Z AND 20Z TUESDAY. PRECIP AND WINDS WILL
TAPER OFF BY LATE TUESDAY AFTERNOON.
VICINITY OF KSFO...VFR CIGS SHOULD CONTINUE THROUGH AT LEAST
MIDNIGHT BUT THEN MVFR CIGS SHOULD DEVELOP BY 11Z WHEN PRECIP
BEGINS. FROM ABOUT 15Z TO 19Z EXPECT PRECIP TO INCREASE IN
INTENSITY...SOUTHEAST WINDS TO INCREASE...AND CIGS TO LOWER
FURTHER. FRONTAL PASSAGE EXPECTED AROUND 19Z ON TUESDAY. SHOWERS
MAY LINGER FOR A FEW HOURS AFTER FRONTAL PASSAGE THROUGH MID
AFTERNOON TUESDAY. WINDS WILL REMAIN GUSTY FROM THE SOUTHWEST BUT
GRADUALLY DECREASE BY LATE AFTERNOON.
SFO BRIDGE APPROACH...SIMILAR TO KSFO.
MONTEREY BAY AREA TERMINALS...VFR THROUGH LATE EVENING EXCEPT
PATCHY LIFR CONDITIONS IN FOG. THEN MVFR CIGS LIKELY DEVELOPING
BY 09Z. GIGS WILL LOWER BY 14Z TUESDAY MORNING AS PRECIP BEGINS.
EXPECT HEAVIEST PRECIP...STRONGEST SOUTHEAST WINDS...AND MOST
INTENSE PRECIP BETWEEN ABOUT 16Z AND 20Z ON TUESDAY. AFTER FRONTAL
PASSAGE EARLY TUESDAY AFTERNOON...LOOK FOR SCATTERED SHOWERS FOR A
FEW HOURS ALONG WITH GRADUALLY DECREASING SOUTHWEST WINDS.
&&
.MARINE...AS OF 09:50 AM PST TUESDAY...STRONG AND GUSTY WINDS
WILL PREVAIL TODAY AS A STORM SYSTEM PASSING THROUGH THE REGION.
WINDS WILL DECREASE RAPIDLY THIS EVENING AFTER THE STORM PASSES.
ANOTHER STORM WILL BRING INCREASING WINDS AGAIN BY FRIDAY. A LONG
PERIOD LARGE SWELL IS FORECAST TO IMPACT THE REGION LATER THIS
WEEK.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.TDAY...SCA...SF BAY UNTIL 3 PM
SCA...PT ARENA TO PT REYES 0-10 NM UNTIL 3 PM
SCA...PT REYES TO PIGEON PT 0-10 NM UNTIL 3 PM
SCA...PIGEON PT TO PT PINOS 0-10 NM UNTIL 3 PM
SCA...PT PINOS TO PT PIEDRAS BLANCAS 0-10 NM UNTIL 3 PM
SCA...PT ARENA TO PIGEON PT 10-60 NM UNTIL 3 PM
SCA...PIGEON PT TO PT PIEDRAS BLANCAS 10-60 NM UNTIL 3 PM
SCA...ROUGH BAR ADVISORY FOR SF BAR UNTIL 3 PM
&&
$$
PUBLIC FORECAST: RGASS
AVIATION: W PI
MARINE: MM
VISIT US AT WWW.WEATHER.GOV/SANFRANCISCO
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AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
352 AM PST TUE JAN 19 2016
.SYNOPSIS...RAIN THIS MORNING...HEAVY AT TIMES BEFORE TURNING TO
SHOWERS FOR THE MIDDAY AND AFTERNOON HOURS. HIGH PRESSURE BUILDS
TONIGHT THROUGH THURSDAY WITH A PERIOD OF DRY AND SEASONABLY MILD
WEATHER. NEXT FRONT ARRIVES THURSDAY NIGHT INTO FRIDAY WITH A
PERIOD OF LIGHT RAIN...POSSIBLY BECOMING HEAVY FOR A TIME FRIDAY
NIGHT WHEN THE UPPER LOW PASSES OVERHEAD WITH LINGERING SHOWERS
SATURDAY. LATEST INDICATIONS SHOW A RETURN OF DRY WEATHER SUNDAY
THROUGH THE MIDDLE OF NEXT WEEK.
&&
.DISCUSSION...AS OF 3:52 AM PST TUESDAY...INITIAL RAIN BAND IS
MOVING ONSHORE AS OF THIS WRITING...MAINLY ARRIVING FROM THE WEST
WITH RAIN DEVELOPING OVER MOST OF THE DISTRICT. AMOUNTS SO FAR
HAVE BEEN LIGHT BUT THAT SHOULD CHANGE QUICKLY OVER THE NEXT
SEVERAL HOURS THAT WILL ENCOMPASS THE MORNING COMMUTE. SATELLITE
IMAGERY SHOWS RAPIDLY COOLING CLOUD TOPS OFFSHORE WITH INCOMING
JET STREAK AND ASSOCIATED SHORTWAVE. AMSU TPW SHOWS GOOD MOISTURE
TAP BUT BEST PLUME OF 1.5 TPW MAY STAY JUST OFFSHORE. LATEST
OBSERVED TRENDS SUGGESTS THAT SOME OF THE HEAVIEST RAIN MAY NOW
SHIFT SLIGHTLY SOUTHWARD AND IMPACT THE SANTA CRUZ MTNS AND SANTA
LUCIA RANGE ABOVE BIG SUR. THE HRRR AND RAP MESOSCALE/SHORT TERM
MODELS SHOW 3-4 INCHES FOR THE SANTA CRUZ MTNS WITH SOME OF THE
HRRR RUNS IN EXCESS OF 7 INCHES ABOVE BIG SUR...ALL OCCURRING OVER
THE NEXT 8-10 HOURS. WILL BE WATCHING RAIN RATES AND TRENDS
CLOSELY THE NEXT FEW HOURS FOR POSSIBLE URBAN AND SMALL STREAM
FLOOD ADVISORIES THROUGHOUT THE BAY AREA...WITH POSSIBILITY THAT
WARNINGS COULD BE NEEDED FOR THE HILLS ABOVE BIG SUR. UPSHOT IS
THAT THE COMMUTE WILL QUICKLY TURN UGLY FOR THE BAY AREA WITH
HEAVIEST RAINS FROM NOW THROUGH ROUGHLY 18-20Z. SIMILAR TO
YESTERDAYS STORM THE STEADY RAIN SHOULD END ABRUPTLY AROUND MIDDAY
IN THE BAY AREA WHILE HANGING ON LONGER FOR THE CENTRAL COAST.
SHOWERS THIS AFTERNOON BUT EVEN THOSE WILL BE LIMITED WITH SOME
LATE DAY PEAKS OF SUNSHINE. WINDS WITH TODAYS FRONT WILL BE
SOUTHERLY THIS MORNING....STRONGEST ON THE COAST AND OVER THE
OCEAN WITH GUSTS AROUND 30 MPH. WINDS TURN WEST BY MIDDAY BUT
GIVEN THE LACK OF COLD ADVECTION THE WESTERLY WINDS WONT BE TOO
STRONG.
HAVE REMOVED ALL CHANCES OF RAIN FOR THIS EVENING AS THE SYSTEM
WILL QUICKLY MOVE EASTWARD. HIGH PRESSURE BUILDS IN TONIGHT AND
LASTS THROUGH THURSDAY. AIRMASS IS MILD AND EXPECT DAYTIME HIGHS
TO BE COMFORTABLY IN THE 60S MIDWEEK WITH MILD OVERNIGHT LOWS
GENERALLY IN THE 40S.
NEXT FRONT ARRIVES THURSDAY NIGHT. INITIAL BOUNDARY DOESN`T LOOK
TOO IMPRESSIVE WITH SOUTHERLY WINDS NOT-FAVORABLE FOR OROGRAPHICS.
GFS AND ECMWF BOTH SHOW FAIRLY WEAK FRONT MOVING THROUGH TIL
MIDDAY FRIDAY...THEN COLD UPPER TROUGH SHOULD PASS OVER THE REGION
AND ALLOW FOR AN UPTICK IN RAIN SHOWERS AND INTENSITY WITH SHOWERS
LASTING INTO SATURDAY. STILL SEVERAL DAYS OUT SO THATLL BECOME THE
FOCUS AFTER TODAYS EVENT.
LATEST MODEL TREND OVER THE LAST 24 HOURS HAS BEEN TO BUILD HIGH
PRESSURE SATURDAY NIGHT THROUGH THE MIDDLE OF NEXT WEEK. IN
COORDINATION WITH WFO EUREKA REMOVED NEARLY ALL RAIN CHANCES FOR
THE NORTH BAY AS WELL AS THE REST OF THE DISTRICT AFTER SATURDAY
NIGHT.
HOWEVER MUST POINT OUT THE LONG RANGE GFS CONTINUES TO SHOW
ANOTHER COLD WEST COAST TROUGH AND ASSOCIATED RAIN ARRIVING
SOMETIME AROUND JAN 29TH WITH EXTENDED GFS AND CFS MODELS KEEPING
PATTERN ACTIVE.
&&
.AVIATION...AS OF 9:45 PM PST MONDAY...CLOUDS WILL LOWER AND
BECOMING MORE WIDESPREAD OVERNIGHT AS THE NEXT WEATHER SYSTEM
APPROACHES THE COAST. LOOK FOR MVFR CIGS AND RAIN TO SPREAD FROM
NORTH TO SOUTH BETWEEN 08Z AND 14Z. SOUTH TO SOUTHEAST WINDS WILL
ALSO INCREASE IN THIS TIME PERIOD. A PERIOD OF STRONGER
WINDS...MORE INTENSE PRECIP...AND LOWER CIGS IS LIKELY JUST AHEAD
OF THE FRONT BETWEEN 15Z AND 20Z TUESDAY. PRECIP AND WINDS WILL
TAPER OFF BY LATE TUESDAY AFTERNOON.
VICINITY OF KSFO...VFR CIGS SHOULD CONTINUE THROUGH AT LEAST
MIDNIGHT BUT THEN MVFR CIGS SHOULD DEVELOP BY 11Z WHEN PRECIP
BEGINS. FROM ABOUT 15Z TO 19Z EXPECT PRECIP TO INCREASE IN
INTENSITY...SOUTHEAST WINDS TO INCREASE...AND CIGS TO LOWER
FURTHER. FRONTAL PASSAGE EXPECTED AROUND 19Z ON TUESDAY. SHOWERS
MAY LINGER FOR A FEW HOURS AFTER FRONTAL PASSAGE THROUGH MID
AFTERNOON TUESDAY. WINDS WILL REMAIN GUSTY FROM THE SOUTHWEST BUT
GRADUALLY DECREASE BY LATE AFTERNOON.
SFO BRIDGE APPROACH...SIMILAR TO KSFO.
MONTEREY BAY AREA TERMINALS...VFR THROUGH LATE EVENING EXCEPT
PATCHY LIFR CONDITIONS IN FOG. THEN MVFR CIGS LIKELY DEVELOPING
BY 09Z. GIGS WILL LOWER BY 14Z TUESDAY MORNING AS PRECIP BEGINS.
EXPECT HEAVIEST PRECIP...STRONGEST SOUTHEAST WINDS...AND MOST
INTENSE PRECIP BETWEEN ABOUT 16Z AND 20Z ON TUESDAY. AFTER FRONTAL
PASSAGE EARLY TUESDAY AFTERNOON...LOOK FOR SCATTERED SHOWERS FOR A
FEW HOURS ALONG WITH GRADUALLY DECREASING SOUTHWEST WINDS.
&&
.MARINE...AS OF 02:57 AM PST TUESDAY...A STORM SYSTEM WILL MOVE
THROUGH THE AREA TODAY WITH RAIN AND BRIEF MODERATE SOUTHERLY
WINDS. WINDS WILL DECREASE RAPIDLY THIS EVENING AFTER THE STORM
PASSES. ANOTHER STORM WILL BRING INCREASING WINDS AGAIN BY FRIDAY.
A LONG PERIOD LARGE SWELL IS FORECAST TO IMPACT THE REGION LATER
THIS WEEK.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.TNGT...SCA...SF BAY FROM 3 AM
SCA...PT ARENA TO PT REYES 0-10 NM FROM 3 AM
SCA...PT REYES TO PIGEON PT 0-10 NM FROM 3 AM
SCA...PIGEON PT TO PT PINOS 0-10 NM FROM 3 AM
SCA...PT PINOS TO PT PIEDRAS BLANCAS 0-10 NM FROM 3 AM
SCA...PIGEON PT TO PT PIEDRAS BLANCAS 10-60 NM FROM 3 AM
SCA...PT ARENA TO PIGEON PT 10-60 NM
SCA...ROUGH BAR ADVISORY FOR SF BAR
&&
$$
PUBLIC FORECAST: R_WALBRUN
AVIATION: W PI
MARINE: W PI
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AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
904 AM MST TUE JAN 19 2016
.UPDATE...
ISSUED AT 859 AM MST TUE JAN 19 2016
SOME LINGERING SNOW IN THE MOUNTAINS AND OVER THE PALMER DIVIDE
THIS MORNING...OTHERWISE HAVE DROPPED THE SNOW FM THE REST OF THE
ZONES. CONDITIONS SHOULD CONTINUE TO IMPROVE FM NORTH TO SOUTH THE
REST OF THE MORNING.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 351 AM MST TUE JAN 19 2016
COLD FRONT IS THROUGH DENVER BUT COLDEST AIR IS LAGGING BEHIND.
THERE WAS SOME RAIN INITIALLY BUT HAS TURNED OR WILL TURN TO ALL
SNOW VERY QUICKLY. HEAVIEST PRECIPITATION SEEMS TO BE QUICKLY
FOCUSING IN/NEAR THE SOUTHERN FOOTHILLS AND PALMER DIVIDE AREA
THIS MORNING. OPERATIONAL HRRR AND RAP SEEM TO BE RUNNING AN HOUR
OR TWO BEHIND CURRENT LOCATION. HOWEVER...NEW EXPERIMENTAL HRRR
SEEMS MUCH BETTER WITH THE DRYING FROM THE NORTH. THIS DRYING IS
ALREADY NOTED IN THE CHEYENNE/FORT COLLINS/GREELEY AREA AND THIS
DRIER WILL CONTINUE TO OCCUR EARLY THIS MORNING. PRECIPITATION
SHOULD BE ALL BUT GONE IN THE DENVER METRO AREA BY 7 AM...BUT
NORTHERLY ANTICYCLONIC UPSLOPE COULD KEEP SOME SNOW IN/NEAR THE
SOUTHERN FRONT RANGE FOOTHILLS/PALMER DIVIDE AS LATE AS 9-10 AM.
RADAR ECHOES HIGH ENOUGH FOR SOME 1 INCH PER HOUR RATES IN THE
HEAVIER BANDS. TRAVEL IMPACTS ARE MOST LIKELY IN THAT AREA.
MOUNTAIN SNOWFALL WILL ALSO BE DECREASING RATHER QUICKLY THIS
MORNING AS UPPER LEVEL TROUGH MOVES OUT AND RAPID DRYING OCCURS
FROM THE NORTHWEST.
BY LATER THIS MORNING INTO THE AFTERNOON CLOUDS WILL ERODE TO
THE SOUTHEAST WITH SKIES BECOMING MOSTLY SUNNY OVER MOST OF THE
FORECAST AREA. MAY HAVE A FEW CLOUDS TRAPPED IN THE MOUNTAINS BUT
PLAINS SHOULD CERTAINLY BECOME SUNNY. THAT SHOULD HELP TEMPS
BOUNCE BACK INTO THE LOWER TO MID 40S MOST OF THE LOWER ELEVATIONS
ESPECIALLY CONSIDERING RELATIVELY MILD START TO THE DAY.
FOR TONIGHT...MOSTLY CLEAR SKIES...LIGHT WINDS...AND RELATIVELY
HIGH BOUNDARY LAYER MOISTURE WILL LIKELY ALLOW AREAS OF FOG TO
FORM ON THE PLAINS JUST NORTH AND EAST OF DENVER. CLOUDS DO
INCREASE LATER TONIGHT IN ADVANCE OF NEXT SYSTEM SO THAT WOULD
TEND TO ERODE FOG LATER IN THE NIGHT AS LONG AS CLOUDS THICKEN
SUFFICIENTLY. MORE SNOW MOVES INTO THE MOUNTAINS AFTER
MIDNIGHT...WITH UP TO AN INCH OR TWO IN ZONE 31 AND RABBIT EARS
PASS AREA OVERNIGHT.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 351 AM MST TUE JAN 19 2016
THE UPCOMING WEEK WILL FEATURE A PROGRESSIVE UPPER AIR PATTERN
WITH A COUPLE WEATHER DISTURBANCES MOVING ACROSS COLORADO BETWEEN
WEDNESDAY AND MONDAY. THE FIRST DISTURBANCE WILL CROSS THE STATE
IN A COUPLE OF PIECES WEDNESDAY AND WEDNESDAY NIGHT. MOISTURE WILL
BE IN PLACE OVER THE MOUNTAINS THROUGH WEDNESDAY WITH SNOW
DEVELOPING EARLY ON. THE PLAINS WILL BE UNDER DRY...DOWNSLOPING
FLOW THROUGH WEDNESDAY...BUT IN THE EVENING...AS THE PRIMARY
TROUGH AXIS MOVES OUT OF THE MOUNTAINS...SOME SHOWER ACTIVITY MAY
DEVELOP. SNOW ACCUMULATIONS UP TO A FEW INCHES CAN BE EXPECTED IN
THE MOUNTAINS...BUT THE PLAINS SHOULD SEE LITTLE MORE THAN TRACE
AMOUNTS.
THURSDAY THROUGH SATURDAY WILL BRING A STRONG UPPER RIDGE OVER THE
STATE WITH DRY WEATHER AND WARMING TEMPERATURES. SATURDAY SHOULD
BE THE WARMEST DAY OF THE BUNCH WITH HIGHS IN THE LOWER 50S ON THE
PLAINS. ALL OF THE WARMING WILL BE IN ADVANCE OF THE NEXT UPPER
TROUGH WHICH WILL PROGRESS ACROSS THE STATE SATURDAY NIGHT AND
SUNDAY. THE ECMWF SOLUTION IS A LITTLE FASTER THAN THE LATEST RUNS
OF THE GFS...SO TIMING OF PRECIPITATION WITH THIS SYSTEM IS
DIFFICULT AT THIS TIME. THE ECMWF POINTS TO SNOW IN THE MOUNTAINS
AFTER MIDNIGHT SATURDAY NIGHT WHILE THE GFS DOESN`T BRING SNOW TO
THE MOUNTAINS UNTIL AFTER SUNRISE SUNDAY MORNING. THE UPPER TROUGH
AXIS SHOULD BE OVER EASTERN COLORADO SUNDAY AFTERNOON PRODUCING SOME
RAIN OR SNOW. THE PHASE OF PRECIPITATION IS GOING TO DEPEND ON THE
STRENGTH OF THE SURFACE COLD FRONT ASSOCIATED WITH THE UPPER
SYSTEM...AND AT THIS POINT IT DOES NOT LOOK ALL THAT STRONG.
SUBSEQUENT MODEL RUNS WILL HELP TO DEFINE THE STRENGTH AND TIMING
OF SUNDAY`S WEATHER SYSTEM. COOL AND MOIST NORTHWESTERLY FLOW
ALOFT WILL CONTINUE OVER THE STATE NEXT MONDAY WHICH SHOULD BE
ENOUGH TO KEEP SNOW SHOWERS GOING IN THE MOUNTAINS THROUGH THEN.
PLAINS LOCATIONS SHOULD BE DRIER...BUT WITH COOLER TEMPERATURES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 859 AM MST TUE JAN 19 2016
DRIER AIR CONTINUES TO MOVE IN FROM THE NORTH...CONDITIONS SHOULD
CONTINUE TO IMPROVE THROUGH 17Z WITH VFR CONDITIONS AT ALL THE
AIRPORTS BY THIS AFTERNOON AND CLEARING SKIES. LIGHT SOUTHWEST
WINDS AT THIS TIME...WILL LIKELY TURN SOUTHEAST BY 21Z BUT
REMAINING LIGHT. ANY FOG THREAT TONIGHT WILL BE NORTH OF KDEN AND
KBJC AS LIGHT DRAINAGE WINDS ARE EXPECTED TO DEVELOP. KFNL AND
KGXY MAY SEE DENSE FOG WITH 1/4SM VSBY POSSIBLE AFTER 06Z.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...COOPER
SHORT TERM...BARJENBRUCH
LONG TERM...DANKERS
AVIATION...COOPER
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
351 AM MST TUE JAN 19 2016
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 351 AM MST TUE JAN 19 2016
COLD FRONT IS THROUGH DENVER BUT COLDEST AIR IS LAGGING BEHIND.
THERE WAS SOME RAIN INITIALLY BUT HAS TURNED OR WILL TURN TO ALL
SNOW VERY QUICKLY. HEAVIEST PRECIPITATION SEEMS TO BE QUICKLY
FOCUSING IN/NEAR THE SOUTHERN FOOTHILLS AND PALMER DIVIDE AREA
THIS MORNING. OPERATIONAL HRRR AND RAP SEEM TO BE RUNNING AN HOUR
OR TWO BEHIND CURRENT LOCATION. HOWEVER...NEW EXPERIMENTAL HRRR
SEEMS MUCH BETTER WITH THE DRYING FROM THE NORTH. THIS DRYING IS
ALREADY NOTED IN THE CHEYENNE/FORT COLLINS/GREELEY AREA AND THIS
DRIER WILL CONTINUE TO OCCUR EARLY THIS MORNING. PRECIPITATION
SHOULD BE ALL BUT GONE IN THE DENVER METRO AREA BY 7 AM...BUT
NORTHERLY ANTICYCLONIC UPSLOPE COULD KEEP SOME SNOW IN/NEAR THE
SOUTHERN FRONT RANGE FOOTHILLS/PALMER DIVIDE AS LATE AS 9-10 AM.
RADAR ECHOES HIGH ENOUGH FOR SOME 1 INCH PER HOUR RATES IN THE
HEAVIER BANDS. TRAVEL IMPACTS ARE MOST LIKELY IN THAT AREA.
MOUNTAIN SNOWFALL WILL ALSO BE DECREASING RATHER QUICKLY THIS
MORNING AS UPPER LEVEL TROUGH MOVES OUT AND RAPID DRYING OCCURS
FROM THE NORTHWEST.
BY LATER THIS MORNING INTO THE AFTERNOON CLOUDS WILL ERODE TO
THE SOUTHEAST WITH SKIES BECOMING MOSTLY SUNNY OVER MOST OF THE
FORECAST AREA. MAY HAVE A FEW CLOUDS TRAPPED IN THE MOUNTAINS BUT
PLAINS SHOULD CERTAINLY BECOME SUNNY. THAT SHOULD HELP TEMPS
BOUNCE BACK INTO THE LOWER TO MID 40S MOST OF THE LOWER ELEVATIONS
ESPECIALLY CONSIDERING RELATIVELY MILD START TO THE DAY.
FOR TONIGHT...MOSTLY CLEAR SKIES...LIGHT WINDS...AND RELATIVELY
HIGH BOUNDARY LAYER MOISTURE WILL LIKELY ALLOW AREAS OF FOG TO
FORM ON THE PLAINS JUST NORTH AND EAST OF DENVER. CLOUDS DO
INCREASE LATER TONIGHT IN ADVANCE OF NEXT SYSTEM SO THAT WOULD
TEND TO ERODE FOG LATER IN THE NIGHT AS LONG AS CLOUDS THICKEN
SUFFICIENTLY. MORE SNOW MOVES INTO THE MOUNTAINS AFTER
MIDNIGHT...WITH UP TO AN INCH OR TWO IN ZONE 31 AND RABBIT EARS
PASS AREA OVERNIGHT.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 351 AM MST TUE JAN 19 2016
THE UPCOMING WEEK WILL FEATURE A PROGRESSIVE UPPER AIR PATTERN
WITH A COUPLE WEATHER DISTURBANCES MOVING ACROSS COLORADO BETWEEN
WEDNESDAY AND MONDAY. THE FIRST DISTURBANCE WILL CROSS THE STATE
IN A COUPLE OF PIECES WEDNESDAY AND WEDNESDAY NIGHT. MOISTURE WILL
BE IN PLACE OVER THE MOUNTAINS THROUGH WEDNESDAY WITH SNOW
DEVELOPING EARLY ON. THE PLAINS WILL BE UNDER DRY...DOWNSLOPING
FLOW THROUGH WEDNESDAY...BUT IN THE EVENING...AS THE PRIMARY
TROUGH AXIS MOVES OUT OF THE MOUNTAINS...SOME SHOWER ACTIVITY MAY
DEVELOP. SNOW ACCUMULATIONS UP TO A FEW INCHES CAN BE EXPECTED IN
THE MOUNTAINS...BUT THE PLAINS SHOULD SEE LITTLE MORE THAN TRACE
AMOUNTS.
THURSDAY THROUGH SATURDAY WILL BRING A STRONG UPPER RIDGE OVER THE
STATE WITH DRY WEATHER AND WARMING TEMPERATURES. SATURDAY SHOULD
BE THE WARMEST DAY OF THE BUNCH WITH HIGHS IN THE LOWER 50S ON THE
PLAINS. ALL OF THE WARMING WILL BE IN ADVANCE OF THE NEXT UPPER
TROUGH WHICH WILL PROGRESS ACROSS THE STATE SATURDAY NIGHT AND
SUNDAY. THE ECMWF SOLUTION IS A LITTLE FASTER THAN THE LATEST RUNS
OF THE GFS...SO TIMING OF PRECIPITATION WITH THIS SYSTEM IS
DIFFICULT AT THIS TIME. THE ECMWF POINTS TO SNOW IN THE MOUNTAINS
AFTER MIDNIGHT SATURDAY NIGHT WHILE THE GFS DOESN`T BRING SNOW TO
THE MOUNTAINS UNTIL AFTER SUNRISE SUNDAY MORNING. THE UPPER TROUGH
AXIS SHOULD BE OVER EASTERN COLORADO SUNDAY AFTERNOON PRODUCING SOME
RAIN OR SNOW. THE PHASE OF PRECIPITATION IS GOING TO DEPEND ON THE
STRENGTH OF THE SURFACE COLD FRONT ASSOCIATED WITH THE UPPER
SYSTEM...AND AT THIS POINT IT DOES NOT LOOK ALL THAT STRONG.
SUBSEQUENT MODEL RUNS WILL HELP TO DEFINE THE STRENGTH AND TIMING
OF SUNDAY`S WEATHER SYSTEM. COOL AND MOIST NORTHWESTERLY FLOW
ALOFT WILL CONTINUE OVER THE STATE NEXT MONDAY WHICH SHOULD BE
ENOUGH TO KEEP SNOW SHOWERS GOING IN THE MOUNTAINS THROUGH THEN.
PLAINS LOCATIONS SHOULD BE DRIER...BUT WITH COOLER TEMPERATURES.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 351 AM MST TUE JAN 19 2016
MAIN BAND OF SNOW APPEARS TO HAVE ALREADY SHIFTED SOUTHWEST OF
KDEN SO MAINLY PERIODS OF LIGHT SNOW AND STRATUS DECK OF 800-2500
FEET EXPECTED THERE TIL AROUND 12Z-14Z. THEN THAT SHOULD ERODE AS
WELL AS DRIER AIR MOVES IN FROM THE NORTH. KAPA AND KBJC COULD SEE
SIMILAR CONDITIONS LINGER MAYBE AN HOUR OR SO LONGER...BUT OVERALL
CONDITIONS WILL RAPIDLY IMPROVE AS MUCH DRIER AIR MOVES IN BY 15Z-
17Z WITH VFR CONDITIONS AND CLEARING SKIES. NORTHERLY WINDS
BECOMING LIGHT AND VARIABLE BY 16Z-17Z AND THEN LIKELY TURNING
SOUTHEAST BY 21Z-22Z BUT REMAINING LIGHT. ANY FOG THREAT TONIGHT
WILL BE NORTH OF KDEN AND KBJC AS LIGHT DRAINAGE WINDS ARE
EXPECTED TO DEVELOP. KFNL AND KGXY MAY SEE DENSE FOG WITH 1/4SM
VSBY POSSIBLE AFTER 06Z.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...BARJENBRUCH
LONG TERM...DANKERS
AVIATION...BARJENBRUCH
AREA FORECAST DISCUSSION
NWS MIAMI FL
1232 PM EST TUE JAN 19 2016
.AVIATION...
VFR WILL CONTINUE THROUGH THE PERIOD WITH SCT-BKN MID TO HIGH
LEVEL CLOUDINESS...BUT WITH NO RAIN. WINDS WILL PREVAIL OUT OF
THE N-NW NEAR 10 KT AT THE EAST COAST TERMINALS...THEN ARE
FORECAST TO BECOME N-NE LATE IN THE DAY BEFORE LIKELY TURNING BACK
TO THE NNW THIS EVENING/OVERNIGHT. FOR KAPF...N-NE WINDS 5-10 KT
WILL PREVAIL THROUGH THE PERIOD. /GREGORIA
&&
.PREV DISCUSSION... /ISSUED 1002 AM EST TUE JAN 19 2016/
UPDATE...
A CHILLY MORNING AGAIN ACROSS SOUTH FL WITH LOWS IN THE 50S IN THE
METROPOLITAN AREAS TO THE 40S ACROSS THE INTERIOR. ASIDE FROM
INCREASING CLOUD COVER ESPECIALLY SOUTHERN LOCALES, NO SIGNIFICANT
CHANGES WERE MADE TO THE FORECAST THIS MORNING. DRY AND COOL
CONDITIONS WILL PREVAIL THIS AFTERNOON. PLEASE SEE PREVIOUS
DISCUSSION BELOW FOR FURTHER FORECAST DETAILS. /GREGORIA
PREV DISCUSSION... /ISSUED 627 AM EST TUE JAN 19 2016/
AVIATION...
VFR WILL CONTINUE THROUGH THE PERIOD WITH MID TO HIGH LEVEL
BROKEN CLOUDINESS...BUT WITH NO RAIN. WINDS WILL PREVAIL OUT OF
THE N-NW NEAR 10 KT AT THE EAST COAST TERMINALS...THEN ARE FORECAST
TO BECOME N-NE LATE IN THE DAY. FOR KAPF...N-NE WINDS 5-10 KT WILL
PREVAIL THROUGH THE PERIOD. /GREGORIA
PREV DISCUSSION... /ISSUED 316 AM EST TUE JAN 19 2016/
DISCUSSION...
MODELS REMAIN IN GOOD AGREEMENT WITH HIGH PRESSURE CONTINUING TO
BUILD OVER THE SOUTHEAST UNITED STATES. THERE IS AN AREA OF HIGH
CLOUDS THAT HAS BEEN STREAMING OVER SOUTH FLORIDA SINCE YESTERDAY.
AS A 500MB TROUGH PUSHES EAST OVER THE NEXT DAY, THE HIGH CLOUDS
SHOULD ALSO BEGIN TO EXIT THE REGION. FOR THE MOST PART, DRY
WEATHER FOR THE CWA. THE EXCEPTION IS SOME SHOWER ACTIVITY WELL
OFFSHORE, OVER THE ATLANTIC. THIS LOOKS TO BE ASSOCIATED WITH A
WEAK SURFACE TROUGH. IT IS NOT ANALYZED WELL IN THE SYNOPTIC
MODELS, BUT THE HRRR IS SHOWING IT AND SEEMS TO HAVE A GOOD HANDLE
ON THINGS.
THIS WEAK TROUGH WILL GET PUSH AWAY FROM SOUTH FLORIDA AS HIGH
PRESSURE BUILDS. ALSO, THE WIND WILL FIRST BEGIN TO RELAX THROUGH
THE DAY, THEN BEGIN A TURN TO THE NORTHEAST BY WEDNESDAY MORNING.
HOWEVER, THE AIR MASS WILL REMAIN DRY AND THE WEATHER WILL
CONTINUE TO BE QUIET THROUGH THE MIDDLE OF THE WEAK. THIS AIR MASS
IS ALSO FAIRLY COOL, AND WILL KEEP THE TEMPS ACROSS THE AREA BELOW
NORMAL FOR A FEW DAYS.
AS THE HIGH BUILDS FURTHER TO THE SOUTH, THE WIND WILL TURN MORE
TO THE EAST, PRETTY MUCH BY WEDNESDAY AFTERNOON. THIS WILL BRING
SOME MOISTURE BACK TO THE AREA, AND BEGIN TO MODIFY THE
TEMPERATURES. SO, AFTER A CHILLY START WEDNESDAY MORNING, WHICH
SHOULD SEE LOWS IN THE UPPER 30S WEST OF THE LAKE, LOW 50S OVER
THE SOUTHEAST FLORIDA METRO AREAS, THE AIR MASS WILL BEGIN A
WARMING TREND. HIGHS WEDNESDAY WILL BE AROUND 70, WITH THE
NORTHWEST PORTION OF THE CWA IN THE UPPER 60S AND THE SOUTHEAST
COAST IN THE LOW 70S.
ELSEWHERE ON WEDNESDAY AFTERNOON, A LOW PRESSURE SYSTEM WILL
DEVELOP LEEWARD OF THE ROCKIES, OVER THE HIGH PLAINS. THIS LOW
WILL BE OUR NEXT WEATHER MAKER FOR SOUTH FLORIDA. BY THURSDAY
AFTERNOON, WHICH WILL BE WARMER THAN WEDNESDAY, BUT STILL LOOKS
DRY, THE LOW WILL TRACK INTO THE SOUTHERN MISSISSIPPI VALLEY, BUT
REMAIN NORTH OF THE GULF. THIS WILL BEGIN TO TURN THE WIND MORE TO
THE SOUTH BY FRIDAY MORNING. THIS WILL BRING MOISTURE BACK, AS
WELL AS ALLOW THE AIR MASS TO WARM INTO THE MID TO UPPER 70S. THIS
WILL ALSO BRING OUR NEXT CHANCE FOR SHOWERS AND STORMS FROM
THURSDAY NIGHT, THROUGH FRIDAY, AND EVEN SOME REMNANT SHOWER
ACTIVITY FRIDAY NIGHT INTO SATURDAY MORNING.
FOR THIS NEXT SYSTEM, IT DOES TRACK FURTHER NORTH THAN THE SYSTEM
THIS PAST SUNDAY MORNING. ALSO, MODELS ARE INDICATING THAT THERE
SHOULD BE SHOWER ACTIVITY WELL AHEAD OF THE SYSTEM. THIS COULD
POTENTIALLY REDUCE INSTABILITY AHEAD OF THE COLD FRONT. THE GFS IS
NOT TOO EXCITED ABOUT THE AMOUNT OF CAPE BY FRIDAY MORNING, WITH
ONLY A FEW HUNDRED JOULES FRIDAY AFTERNOON. THERE IS A BROAD JET
STREAK WITH THE RIGHT EXIT QUADRANT IN THE VICINITY, LEADING TO
SOME CONVERGENCE ALOFT IN THIS GENERAL AREA. THE GFS DOES SHOW A
WEAK LOW LEVEL JET AT 850 MB AT ABOUT 40 KTS.SO, THE ELEMENTS JUST
DO NOT LOOK AS THOUGH THEY ARE LINING UP AS THEY DID WITH THE
LATEST SYSTEM. GFS SHOWS THE HELICITY TO BE A MAX OF 100 M^2*S^-2,
JUST AHEAD OF THE FRONT, NOTHING COMPARED TO THE 300-400 VALUES
FROM THE OTHER DAY. STILL, THERE COULD BE SHOWERS AND A FEW
THUNDERSTORMS THAT PRODUCE SOME GUSTY WIND AS THE FRONT PUSHES
THROUGH ON FRIDAY. THERE WILL BE A CONCERN ABOUT THE SUSTAINED,
NON-CONVECTIVE WIND FROM FRIDAY NIGHT THROUGH SATURDAY. MODEL
BLENDS ARE SHOWING WIND OVER THE MARINE AREAS TO BE NEARING 30KTS,
WITH HIGHER GUSTS, AND 15 TO 20 KTS OVER THE MAINLAND. THIS WILL
MEAN THERE WILL BE SOME MARINE CONCERNS FOR THIS PERIOD.
BEHIND THIS FRONT, ANOTHER COOLER AIR MASS WILL SETTLE IN OVER THE
CWA FOR THE REMAINDER OF THE WEEKEND, INTO THE BEGINNING OF NEXT
WEEK, WHICH SHOULD SEE QUIET WEATHER CONDITIONS.
AVIATION...
HIGH PRESSURE IS BUILDING OVER SOUTH FLORIDA. THIS WILL KEEP THE
WEATHER QUIET FOR THE TAF SITES, AS WELL AS VFR CONDITIONS THROUGH
THE TAF PERIOD. EVEN SO, THERE ARE SOME MID AND UPPER LEVEL CLOUDS
THAT ARE GIVING CIGS OF BKN045, AS WELL AS A DECK OF HIGH CLOUDS.
THE WIND WILL CONTINUE OUT OF THE NORTH TO NORTHWEST INTO THE
AFTERNOON, BEFORE TRYING TO TURN TO THE NORTHEAST.
MARINE...
MARINE CONDITIONS ARE HAZARDOUS FOR SMALL CRAFT TODAY. THIS IS DUE
TO A NORTHERLY WIND BETWEEN 15 AND 20 KTS OPPOSING THE GULF
STREAM, CAUSING SEAS OF 7 TO 8 FEET IN THE GULF STREAM. THE WIND
IS FORECAST TO SUBSIDE TONIGHT, WHICH WILL ALLOW SEAS TO SLOWLY
SUBSIDE BY TOMORROW MORNING. THERE IS A SMALL CRAFT ADVISORY OUT
FOR THE ATLANTIC WATERS. THERE IS ALSO AN AREA OF SHOWERS ORIENTED
NORTH SOUTH IN THE OFFSHORE ATLANTIC WATERS THAT SHOULD SLOWLY
SUBSIDE THIS MORNING. A COLD FRONT AT THE END OF THE WEEK WILL
BRING MARINE CONCERNS INTO THE FORECAST ONCE AGAIN. BESIDES
SHOWERS AND THUNDERSTORMS THAT WILL ACCOMPANY A COLD FRONT, THE
SUSTAINED WIND BEHIND THE FRONT FOR FRIDAY NIGHT INTO SATURDAY
WILL BE NEARING 30 KTS. THIS WILL MAKE FOR HAZARDOUS MARINE
CONDITIONS THIS WEEKEND.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 65 53 71 56 / 0 10 10 10
FORT LAUDERDALE 67 54 71 60 / 0 10 0 10
MIAMI 66 55 70 60 / 0 10 0 10
NAPLES 65 43 72 53 / 0 0 0 0
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...SMALL CRAFT ADVISORY UNTIL 1 AM EST WEDNESDAY FOR AMZ650-651-670-
671.
GM...SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR GMZ656-
657.
SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR GMZ676.
&&
$$
AREA FORECAST DISCUSSION
NWS MIAMI FL
1002 AM EST TUE JAN 19 2016
.UPDATE...
A CHILLY MORNING AGAIN ACROSS SOUTH FL WITH LOWS IN THE 50S IN THE
METROPOLITAN AREAS TO THE 40S ACROSS THE INTERIOR. ASIDE FROM
INCREASING CLOUD COVER ESPECIALLY SOUTHERN LOCALES, NO SIGNIFICANT
CHANGES WERE MADE TO THE FORECAST THIS MORNING. DRY AND COOL
CONDITIONS WILL PREVAIL THIS AFTERNOON. PLEASE SEE PREVIOUS
DISCUSSION BELOW FOR FURTHER FORECAST DETAILS. /GREGORIA
&&
.PREV DISCUSSION... /ISSUED 627 AM EST TUE JAN 19 2016/
AVIATION...
VFR WILL CONTINUE THROUGH THE PERIOD WITH MID TO HIGH LEVEL
BROKEN CLOUDINESS...BUT WITH NO RAIN. WINDS WILL PREVAIL OUT OF
THE N-NW NEAR 10 KT AT THE EAST COAST TERMINALS...THEN ARE FORECAST
TO BECOME N-NE LATE IN THE DAY. FOR KAPF...N-NE WINDS 5-10 KT WILL
PREVAIL THROUGH THE PERIOD. /GREGORIA
PREV DISCUSSION... /ISSUED 316 AM EST TUE JAN 19 2016/
DISCUSSION...
MODELS REMAIN IN GOOD AGREEMENT WITH HIGH PRESSURE CONTINUING TO
BUILD OVER THE SOUTHEAST UNITED STATES. THERE IS AN AREA OF HIGH
CLOUDS THAT HAS BEEN STREAMING OVER SOUTH FLORIDA SINCE YESTERDAY.
AS A 500MB TROUGH PUSHES EAST OVER THE NEXT DAY, THE HIGH CLOUDS
SHOULD ALSO BEGIN TO EXIT THE REGION. FOR THE MOST PART, DRY
WEATHER FOR THE CWA. THE EXCEPTION IS SOME SHOWER ACTIVITY WELL
OFFSHORE, OVER THE ATLANTIC. THIS LOOKS TO BE ASSOCIATED WITH A
WEAK SURFACE TROUGH. IT IS NOT ANALYZED WELL IN THE SYNOPTIC
MODELS, BUT THE HRRR IS SHOWING IT AND SEEMS TO HAVE A GOOD HANDLE
ON THINGS.
THIS WEAK TROUGH WILL GET PUSH AWAY FROM SOUTH FLORIDA AS HIGH
PRESSURE BUILDS. ALSO, THE WIND WILL FIRST BEGIN TO RELAX THROUGH
THE DAY, THEN BEGIN A TURN TO THE NORTHEAST BY WEDNESDAY MORNING.
HOWEVER, THE AIR MASS WILL REMAIN DRY AND THE WEATHER WILL
CONTINUE TO BE QUIET THROUGH THE MIDDLE OF THE WEAK. THIS AIR MASS
IS ALSO FAIRLY COOL, AND WILL KEEP THE TEMPS ACROSS THE AREA BELOW
NORMAL FOR A FEW DAYS.
AS THE HIGH BUILDS FURTHER TO THE SOUTH, THE WIND WILL TURN MORE
TO THE EAST, PRETTY MUCH BY WEDNESDAY AFTERNOON. THIS WILL BRING
SOME MOISTURE BACK TO THE AREA, AND BEGIN TO MODIFY THE
TEMPERATURES. SO, AFTER A CHILLY START WEDNESDAY MORNING, WHICH
SHOULD SEE LOWS IN THE UPPER 30S WEST OF THE LAKE, LOW 50S OVER
THE SOUTHEAST FLORIDA METRO AREAS, THE AIR MASS WILL BEGIN A
WARMING TREND. HIGHS WEDNESDAY WILL BE AROUND 70, WITH THE
NORTHWEST PORTION OF THE CWA IN THE UPPER 60S AND THE SOUTHEAST
COAST IN THE LOW 70S.
ELSEWHERE ON WEDNESDAY AFTERNOON, A LOW PRESSURE SYSTEM WILL
DEVELOP LEEWARD OF THE ROCKIES, OVER THE HIGH PLAINS. THIS LOW
WILL BE OUR NEXT WEATHER MAKER FOR SOUTH FLORIDA. BY THURSDAY
AFTERNOON, WHICH WILL BE WARMER THAN WEDNESDAY, BUT STILL LOOKS
DRY, THE LOW WILL TRACK INTO THE SOUTHERN MISSISSIPPI VALLEY, BUT
REMAIN NORTH OF THE GULF. THIS WILL BEGIN TO TURN THE WIND MORE TO
THE SOUTH BY FRIDAY MORNING. THIS WILL BRING MOISTURE BACK, AS
WELL AS ALLOW THE AIR MASS TO WARM INTO THE MID TO UPPER 70S. THIS
WILL ALSO BRING OUR NEXT CHANCE FOR SHOWERS AND STORMS FROM
THURSDAY NIGHT, THROUGH FRIDAY, AND EVEN SOME REMNANT SHOWER
ACTIVITY FRIDAY NIGHT INTO SATURDAY MORNING.
FOR THIS NEXT SYSTEM, IT DOES TRACK FURTHER NORTH THAN THE SYSTEM
THIS PAST SUNDAY MORNING. ALSO, MODELS ARE INDICATING THAT THERE
SHOULD BE SHOWER ACTIVITY WELL AHEAD OF THE SYSTEM. THIS COULD
POTENTIALLY REDUCE INSTABILITY AHEAD OF THE COLD FRONT. THE GFS IS
NOT TOO EXCITED ABOUT THE AMOUNT OF CAPE BY FRIDAY MORNING, WITH
ONLY A FEW HUNDRED JOULES FRIDAY AFTERNOON. THERE IS A BROAD JET
STREAK WITH THE RIGHT EXIT QUADRANT IN THE VICINITY, LEADING TO
SOME CONVERGENCE ALOFT IN THIS GENERAL AREA. THE GFS DOES SHOW A
WEAK LOW LEVEL JET AT 850 MB AT ABOUT 40 KTS.SO, THE ELEMENTS JUST
DO NOT LOOK AS THOUGH THEY ARE LINING UP AS THEY DID WITH THE
LATEST SYSTEM. GFS SHOWS THE HELICITY TO BE A MAX OF 100 M^2*S^-2,
JUST AHEAD OF THE FRONT, NOTHING COMPARED TO THE 300-400 VALUES
FROM THE OTHER DAY. STILL, THERE COULD BE SHOWERS AND A FEW
THUNDERSTORMS THAT PRODUCE SOME GUSTY WIND AS THE FRONT PUSHES
THROUGH ON FRIDAY. THERE WILL BE A CONCERN ABOUT THE SUSTAINED,
NON-CONVECTIVE WIND FROM FRIDAY NIGHT THROUGH SATURDAY. MODEL
BLENDS ARE SHOWING WIND OVER THE MARINE AREAS TO BE NEARING 30KTS,
WITH HIGHER GUSTS, AND 15 TO 20 KTS OVER THE MAINLAND. THIS WILL
MEAN THERE WILL BE SOME MARINE CONCERNS FOR THIS PERIOD.
BEHIND THIS FRONT, ANOTHER COOLER AIR MASS WILL SETTLE IN OVER THE
CWA FOR THE REMAINDER OF THE WEEKEND, INTO THE BEGINNING OF NEXT
WEEK, WHICH SHOULD SEE QUIET WEATHER CONDITIONS.
AVIATION...
HIGH PRESSURE IS BUILDING OVER SOUTH FLORIDA. THIS WILL KEEP THE
WEATHER QUIET FOR THE TAF SITES, AS WELL AS VFR CONDITIONS THROUGH
THE TAF PERIOD. EVEN SO, THERE ARE SOME MID AND UPPER LEVEL CLOUDS
THAT ARE GIVING CIGS OF BKN045, AS WELL AS A DECK OF HIGH CLOUDS.
THE WIND WILL CONTINUE OUT OF THE NORTH TO NORTHWEST INTO THE
AFTERNOON, BEFORE TRYING TO TURN TO THE NORTHEAST.
MARINE...
MARINE CONDITIONS ARE HAZARDOUS FOR SMALL CRAFT TODAY. THIS IS DUE
TO A NORTHERLY WIND BETWEEN 15 AND 20 KTS OPPOSING THE GULF
STREAM, CAUSING SEAS OF 7 TO 8 FEET IN THE GULF STREAM. THE WIND
IS FORECAST TO SUBSIDE TONIGHT, WHICH WILL ALLOW SEAS TO SLOWLY
SUBSIDE BY TOMORROW MORNING. THERE IS A SMALL CRAFT ADVISORY OUT
FOR THE ATLANTIC WATERS. THERE IS ALSO AN AREA OF SHOWERS ORIENTED
NORTH SOUTH IN THE OFFSHORE ATLANTIC WATERS THAT SHOULD SLOWLY
SUBSIDE THIS MORNING. A COLD FRONT AT THE END OF THE WEEK WILL
BRING MARINE CONCERNS INTO THE FORECAST ONCE AGAIN. BESIDES
SHOWERS AND THUNDERSTORMS THAT WILL ACCOMPANY A COLD FRONT, THE
SUSTAINED WIND BEHIND THE FRONT FOR FRIDAY NIGHT INTO SATURDAY
WILL BE NEARING 30 KTS. THIS WILL MAKE FOR HAZARDOUS MARINE
CONDITIONS THIS WEEKEND.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 65 53 71 56 / 0 10 10 10
FORT LAUDERDALE 67 54 71 60 / 0 10 0 10
MIAMI 66 55 70 60 / 0 10 0 10
NAPLES 65 43 72 53 / 0 0 0 0
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...SMALL CRAFT ADVISORY UNTIL 1 AM EST WEDNESDAY FOR AMZ650-651-670-
671.
GM...SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR GMZ656-
657.
SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR GMZ676.
&&
$$
AREA FORECAST DISCUSSION
NWS MIAMI FL
627 AM EST TUE JAN 19 2016
.AVIATION...
VFR WILL CONTINUE THROUGH THE PERIOD WITH MID TO HIGH LEVEL
BROKEN CLOUDINESS...BUT WITH NO RAIN. WINDS WILL PREVAIL OUT OF
THE N-NW NEAR 10 KT AT THE EAST COAST TERMINALS...THEN ARE FORECAST
TO BECOME N-NE LATE IN THE DAY. FOR KAPF...N-NE WINDS 5-10 KT WILL
PREVAIL THROUGH THE PERIOD. /GREGORIA
&&
.PREV DISCUSSION... /ISSUED 316 AM EST TUE JAN 19 2016/
DISCUSSION...
MODELS REMAIN IN GOOD AGREEMENT WITH HIGH PRESSURE CONTINUING TO
BUILD OVER THE SOUTHEAST UNITED STATES. THERE IS AN AREA OF HIGH
CLOUDS THAT HAS BEEN STREAMING OVER SOUTH FLORIDA SINCE YESTERDAY.
AS A 500MB TROUGH PUSHES EAST OVER THE NEXT DAY, THE HIGH CLOUDS
SHOULD ALSO BEGIN TO EXIT THE REGION. FOR THE MOST PART, DRY
WEATHER FOR THE CWA. THE EXCEPTION IS SOME SHOWER ACTIVITY WELL
OFFSHORE, OVER THE ATLANTIC. THIS LOOKS TO BE ASSOCIATED WITH A
WEAK SURFACE TROUGH. IT IS NOT ANALYZED WELL IN THE SYNOPTIC
MODELS, BUT THE HRRR IS SHOWING IT AND SEEMS TO HAVE A GOOD HANDLE
ON THINGS.
THIS WEAK TROUGH WILL GET PUSH AWAY FROM SOUTH FLORIDA AS HIGH
PRESSURE BUILDS. ALSO, THE WIND WILL FIRST BEGIN TO RELAX THROUGH
THE DAY, THEN BEGIN A TURN TO THE NORTHEAST BY WEDNESDAY MORNING.
HOWEVER, THE AIR MASS WILL REMAIN DRY AND THE WEATHER WILL
CONTINUE TO BE QUIET THROUGH THE MIDDLE OF THE WEAK. THIS AIR MASS
IS ALSO FAIRLY COOL, AND WILL KEEP THE TEMPS ACROSS THE AREA BELOW
NORMAL FOR A FEW DAYS.
AS THE HIGH BUILDS FURTHER TO THE SOUTH, THE WIND WILL TURN MORE
TO THE EAST, PRETTY MUCH BY WEDNESDAY AFTERNOON. THIS WILL BRING
SOME MOISTURE BACK TO THE AREA, AND BEGIN TO MODIFY THE
TEMPERATURES. SO, AFTER A CHILLY START WEDNESDAY MORNING, WHICH
SHOULD SEE LOWS IN THE UPPER 30S WEST OF THE LAKE, LOW 50S OVER
THE SOUTHEAST FLORIDA METRO AREAS, THE AIR MASS WILL BEGIN A
WARMING TREND. HIGHS WEDNESDAY WILL BE AROUND 70, WITH THE
NORTHWEST PORTION OF THE CWA IN THE UPPER 60S AND THE SOUTHEAST
COAST IN THE LOW 70S.
ELSEWHERE ON WEDNESDAY AFTERNOON, A LOW PRESSURE SYSTEM WILL
DEVELOP LEEWARD OF THE ROCKIES, OVER THE HIGH PLAINS. THIS LOW
WILL BE OUR NEXT WEATHER MAKER FOR SOUTH FLORIDA. BY THURSDAY
AFTERNOON, WHICH WILL BE WARMER THAN WEDNESDAY, BUT STILL LOOKS
DRY, THE LOW WILL TRACK INTO THE SOUTHERN MISSISSIPPI VALLEY, BUT
REMAIN NORTH OF THE GULF. THIS WILL BEGIN TO TURN THE WIND MORE TO
THE SOUTH BY FRIDAY MORNING. THIS WILL BRING MOISTURE BACK, AS
WELL AS ALLOW THE AIR MASS TO WARM INTO THE MID TO UPPER 70S. THIS
WILL ALSO BRING OUR NEXT CHANCE FOR SHOWERS AND STORMS FROM
THURSDAY NIGHT, THROUGH FRIDAY, AND EVEN SOME REMNANT SHOWER
ACTIVITY FRIDAY NIGHT INTO SATURDAY MORNING.
FOR THIS NEXT SYSTEM, IT DOES TRACK FURTHER NORTH THAN THE SYSTEM
THIS PAST SUNDAY MORNING. ALSO, MODELS ARE INDICATING THAT THERE
SHOULD BE SHOWER ACTIVITY WELL AHEAD OF THE SYSTEM. THIS COULD
POTENTIALLY REDUCE INSTABILITY AHEAD OF THE COLD FRONT. THE GFS IS
NOT TOO EXCITED ABOUT THE AMOUNT OF CAPE BY FRIDAY MORNING, WITH
ONLY A FEW HUNDRED JOULES FRIDAY AFTERNOON. THERE IS A BROAD JET
STREAK WITH THE RIGHT EXIT QUADRANT IN THE VICINITY, LEADING TO
SOME CONVERGENCE ALOFT IN THIS GENERAL AREA. THE GFS DOES SHOW A
WEAK LOW LEVEL JET AT 850 MB AT ABOUT 40 KTS.SO, THE ELEMENTS JUST
DO NOT LOOK AS THOUGH THEY ARE LINING UP AS THEY DID WITH THE
LATEST SYSTEM. GFS SHOWS THE HELICITY TO BE A MAX OF 100 M^2*S^-2,
JUST AHEAD OF THE FRONT, NOTHING COMPARED TO THE 300-400 VALUES
FROM THE OTHER DAY. STILL, THERE COULD BE SHOWERS AND A FEW
THUNDERSTORMS THAT PRODUCE SOME GUSTY WIND AS THE FRONT PUSHES
THROUGH ON FRIDAY. THERE WILL BE A CONCERN ABOUT THE SUSTAINED,
NON-CONVECTIVE WIND FROM FRIDAY NIGHT THROUGH SATURDAY. MODEL
BLENDS ARE SHOWING WIND OVER THE MARINE AREAS TO BE NEARING 30KTS,
WITH HIGHER GUSTS, AND 15 TO 20 KTS OVER THE MAINLAND. THIS WILL
MEAN THERE WILL BE SOME MARINE CONCERNS FOR THIS PERIOD.
BEHIND THIS FRONT, ANOTHER COOLER AIR MASS WILL SETTLE IN OVER THE
CWA FOR THE REMAINDER OF THE WEEKEND, INTO THE BEGINNING OF NEXT
WEEK, WHICH SHOULD SEE QUIET WEATHER CONDITIONS.
AVIATION...
HIGH PRESSURE IS BUILDING OVER SOUTH FLORIDA. THIS WILL KEEP THE
WEATHER QUIET FOR THE TAF SITES, AS WELL AS VFR CONDITIONS THROUGH
THE TAF PERIOD. EVEN SO, THERE ARE SOME MID AND UPPER LEVEL CLOUDS
THAT ARE GIVING CIGS OF BKN045, AS WELL AS A DECK OF HIGH CLOUDS.
THE WIND WILL CONTINUE OUT OF THE NORTH TO NORTHWEST INTO THE
AFTERNOON, BEFORE TRYING TO TURN TO THE NORTHEAST.
MARINE...
MARINE CONDITIONS ARE HAZARDOUS FOR SMALL CRAFT TODAY. THIS IS DUE
TO A NORTHERLY WIND BETWEEN 15 AND 20 KTS OPPOSING THE GULF
STREAM, CAUSING SEAS OF 7 TO 8 FEET IN THE GULF STREAM. THE WIND
IS FORECAST TO SUBSIDE TONIGHT, WHICH WILL ALLOW SEAS TO SLOWLY
SUBSIDE BY TOMORROW MORNING. THERE IS A SMALL CRAFT ADVISORY OUT
FOR THE ATLANTIC WATERS. THERE IS ALSO AN AREA OF SHOWERS ORIENTED
NORTH SOUTH IN THE OFFSHORE ATLANTIC WATERS THAT SHOULD SLOWLY
SUBSIDE THIS MORNING. A COLD FRONT AT THE END OF THE WEEK WILL
BRING MARINE CONCERNS INTO THE FORECAST ONCE AGAIN. BESIDES
SHOWERS AND THUNDERSTORMS THAT WILL ACCOMPANY A COLD FRONT, THE
SUSTAINED WIND BEHIND THE FRONT FOR FRIDAY NIGHT INTO SATURDAY
WILL BE NEARING 30 KTS. THIS WILL MAKE FOR HAZARDOUS MARINE
CONDITIONS THIS WEEKEND.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 65 53 71 56 / 0 10 10 10
FORT LAUDERDALE 67 54 71 60 / 0 10 0 10
MIAMI 66 55 70 60 / 0 10 0 10
NAPLES 65 43 72 53 / 0 0 0 0
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...SMALL CRAFT ADVISORY UNTIL 1 AM EST WEDNESDAY FOR AMZ650-651-670-
671.
GM...SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR GMZ656-
657.
SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR GMZ676.
&&
$$
AREA FORECAST DISCUSSION
NWS MIAMI FL
316 AM EST TUE JAN 19 2016
.DISCUSSION...
MODELS REMAIN IN GOOD AGREEMENT WITH HIGH PRESSURE CONTINUING TO
BUILD OVER THE SOUTHEAST UNITED STATES. THERE IS AN AREA OF HIGH
CLOUDS THAT HAS BEEN STREAMING OVER SOUTH FLORIDA SINCE YESTERDAY.
AS A 500MB TROUGH PUSHES EAST OVER THE NEXT DAY, THE HIGH CLOUDS
SHOULD ALSO BEGIN TO EXIT THE REGION. FOR THE MOST PART, DRY
WEATHER FOR THE CWA. THE EXCEPTION IS SOME SHOWER ACTIVITY WELL
OFFSHORE, OVER THE ATLANTIC. THIS LOOKS TO BE ASSOCIATED WITH A
WEAK SURFACE TROUGH. IT IS NOT ANALYZED WELL IN THE SYNOPTIC
MODELS, BUT THE HRRR IS SHOWING IT AND SEEMS TO HAVE A GOOD HANDLE
ON THINGS.
THIS WEAK TROUGH WILL GET PUSH AWAY FROM SOUTH FLORIDA AS HIGH
PRESSURE BUILDS. ALSO, THE WIND WILL FIRST BEGIN TO RELAX THROUGH
THE DAY, THEN BEGIN A TURN TO THE NORTHEAST BY WEDNESDAY MORNING.
HOWEVER, THE AIR MASS WILL REMAIN DRY AND THE WEATHER WILL
CONTINUE TO BE QUIET THROUGH THE MIDDLE OF THE WEAK. THIS AIR MASS
IS ALSO FAIRLY COOL, AND WILL KEEP THE TEMPS ACROSS THE AREA BELOW
NORMAL FOR A FEW DAYS.
AS THE HIGH BUILDS FURTHER TO THE SOUTH, THE WIND WILL TURN MORE
TO THE EAST, PRETTY MUCH BY WEDNESDAY AFTERNOON. THIS WILL BRING
SOME MOISTURE BACK TO THE AREA, AND BEGIN TO MODIFY THE
TEMPERATURES. SO, AFTER A CHILLY START WEDNESDAY MORNING, WHICH
SHOULD SEE LOWS IN THE UPPER 30S WEST OF THE LAKE, LOW 50S OVER
THE SOUTHEAST FLORIDA METRO AREAS, THE AIR MASS WILL BEGIN A
WARMING TREND. HIGHS WEDNESDAY WILL BE AROUND 70, WITH THE
NORTHWEST PORTION OF THE CWA IN THE UPPER 60S AND THE SOUTHEAST
COAST IN THE LOW 70S.
ELSEWHERE ON WEDNESDAY AFTERNOON, A LOW PRESSURE SYSTEM WILL
DEVELOP LEEWARD OF THE ROCKIES, OVER THE HIGH PLAINS. THIS LOW
WILL BE OUR NEXT WEATHER MAKER FOR SOUTH FLORIDA. BY THURSDAY
AFTERNOON, WHICH WILL BE WARMER THAN WEDNESDAY, BUT STILL LOOKS
DRY, THE LOW WILL TRACK INTO THE SOUTHERN MISSISSIPPI VALLEY, BUT
REMAIN NORTH OF THE GULF. THIS WILL BEGIN TO TURN THE WIND MORE TO
THE SOUTH BY FRIDAY MORNING. THIS WILL BRING MOISTURE BACK, AS
WELL AS ALLOW THE AIR MASS TO WARM INTO THE MID TO UPPER 70S. THIS
WILL ALSO BRING OUR NEXT CHANCE FOR SHOWERS AND STORMS FROM
THURSDAY NIGHT, THROUGH FRIDAY, AND EVEN SOME REMNANT SHOWER
ACTIVITY FRIDAY NIGHT INTO SATURDAY MORNING.
FOR THIS NEXT SYSTEM, IT DOES TRACK FURTHER NORTH THAN THE SYSTEM
THIS PAST SUNDAY MORNING. ALSO, MODELS ARE INDICATING THAT THERE
SHOULD BE SHOWER ACTIVITY WELL AHEAD OF THE SYSTEM. THIS COULD
POTENTIALLY REDUCE INSTABILITY AHEAD OF THE COLD FRONT. THE GFS IS
NOT TOO EXCITED ABOUT THE AMOUNT OF CAPE BY FRIDAY MORNING, WITH
ONLY A FEW HUNDRED JOULES FRIDAY AFTERNOON. THERE IS A BROAD JET
STREAK WITH THE RIGHT EXIT QUADRANT IN THE VICINITY, LEADING TO
SOME CONVERGENCE ALOFT IN THIS GENERAL AREA. THE GFS DOES SHOW A
WEAK LOW LEVEL JET AT 850 MB AT ABOUT 40 KTS.SO, THE ELEMENTS JUST
DO NOT LOOK AS THOUGH THEY ARE LINING UP AS THEY DID WITH THE
LATEST SYSTEM. GFS SHOWS THE HELICITY TO BE A MAX OF 100 M^2*S^-2,
JUST AHEAD OF THE FRONT, NOTHING COMPARED TO THE 300-400 VALUES
FROM THE OTHER DAY. STILL, THERE COULD BE SHOWERS AND A FEW
THUNDERSTORMS THAT PRODUCE SOME GUSTY WIND AS THE FRONT PUSHES
THROUGH ON FRIDAY. THERE WILL BE A CONCERN ABOUT THE SUSTAINED,
NON-CONVECTIVE WIND FROM FRIDAY NIGHT THROUGH SATURDAY. MODEL
BLENDS ARE SHOWING WIND OVER THE MARINE AREAS TO BE NEARING 30KTS,
WITH HIGHER GUSTS, AND 15 TO 20 KTS OVER THE MAINLAND. THIS WILL
MEAN THERE WILL BE SOME MARINE CONCERNS FOR THIS PERIOD.
BEHIND THIS FRONT, ANOTHER COOLER AIR MASS WILL SETTLE IN OVER THE
CWA FOR THE REMAINDER OF THE WEEKEND, INTO THE BEGINNING OF NEXT
WEEK, WHICH SHOULD SEE QUIET WEATHER CONDITIONS.
&&
.AVIATION...
HIGH PRESSURE IS BUILDING OVER SOUTH FLORIDA. THIS WILL KEEP THE
WEATHER QUIET FOR THE TAF SITES, AS WELL AS VFR CONDITIONS THROUGH
THE TAF PERIOD. EVEN SO, THERE ARE SOME MID AND UPPER LEVEL CLOUDS
THAT ARE GIVING CIGS OF BKN045, AS WELL AS A DECK OF HIGH CLOUDS.
THE WIND WILL CONTINUE OUT OF THE NORTH TO NORTHWEST INTO THE
AFTERNOON, BEFORE TRYING TO TURN TO THE NORTHEAST.
&&
.MARINE...
MARINE CONDITIONS ARE HAZARDOUS FOR SMALL CRAFT TODAY. THIS IS DUE
TO A NORTHERLY WIND BETWEEN 15 AND 20 KTS OPPOSING THE GULF
STREAM, CAUSING SEAS OF 7 TO 8 FEET IN THE GULF STREAM. THE WIND
IS FORECAST TO SUBSIDE TONIGHT, WHICH WILL ALLOW SEAS TO SLOWLY
SUBSIDE BY TOMORROW MORNING. THERE IS A SMALL CRAFT ADVISORY OUT
FOR THE ATLANTIC WATERS. THERE IS ALSO AN AREA OF SHOWERS ORIENTED
NORTH SOUTH IN THE OFFSHORE ATLANTIC WATERS THAT SHOULD SLOWLY
SUBSIDE THIS MORNING. A COLD FRONT AT THE END OF THE WEEK WILL
BRING MARINE CONCERNS INTO THE FORECAST ONCE AGAIN. BESIDES
SHOWERS AND THUNDERSTORMS THAT WILL ACCOMPANY A COLD FRONT, THE
SUSTAINED WIND BEHIND THE FRONT FOR FRIDAY NIGHT INTO SATURDAY
WILL BE NEARING 30 KTS. THIS WILL MAKE FOR HAZARDOUS MARINE
CONDITIONS THIS WEEKEND.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 66 50 71 58 / 0 10 10 0
FORT LAUDERDALE 67 52 71 61 / 0 0 0 0
MIAMI 67 52 73 60 / 0 0 0 0
NAPLES 66 44 71 53 / 0 0 0 0
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR AMZ610-650-
651-670-671.
GM...SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR GMZ656-657-
676.
&&
$$
SHORT TERM...13/SI
LONG TERM....13/SI
AVIATION...13/SI
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
630 PM EST WED JAN 20 2016
.SYNOPSIS...
THE SURFACE PRESSURE RIDGE WILL REMAIN NEAR THE FORECAST AREA
TODAY AND HELP LIMIT MOISTURE ASSOCIATED WITH AN UPPER- LEVEL
DISTURBANCE MOVING INTO THE AREA THIS AFTERNOON. MOISTURE WILL
INCREASE THURSDAY AHEAD OF LOW PRESSURE APPROACHING FROM THE WEST.
THE LOW WILL CROSS THE AREA FRIDAY INTO FRIDAY NIGHT. DRY HIGH
PRESSURE WILL RETURN FOR SUNDAY.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
UPDATE...RADAR...SURFACE OBS...AND PUBLIC REPORTS INDICATE AREA
OF LIGHT RAIN AND LIGHT SLEET MIX INTO THE CSRA AND CENTRAL
MIDLANDS. NO ACCUMULATION EXPECTED AS SURFACE TEMPS WILL
REMAIN WELL ABOVE FREEZING. LATEST HIGH RESOLUTION MODELS SUGGEST
THE PRECIPITATION AREA WILL DECREASE IN COVERAGE AS IT MOVES EAST
ACROSS OUR FORECAST AREA (FA) THROUGH EARLY THIS EVENING.
FOR TONIGHT...MOISTURE WILL FURTHER DIMINISH BEHIND THE MID-LEVEL
SHORTWAVE TROUGH THIS EVENING. THE NAM AND GFS TIME-HEIGHT DISPLAYS
INDICATE LINGERING LOW-LEVEL MOISTURE BELOW THE SNOW-GROWTH ZONE.
FORECASTED A SLIGHT RAIN CHANCE IN THE EVENING BASED ON THE HRRR AND
SPC WRF. LITTLE CONVERGENCE WILL BE ASSOCIATED WITH THE COLD FRONT
LATE. WILL KEEP A LOW CHANCE POP MAINLY IN THE CSRA LATE TONIGHT.
OVERNIGHT LOWS RANGING FROM NEAR 30 EXTREME NORTH TO NEAR 40
SOUTH.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY NIGHT/...
UPDATED...THREAT FOR WINTRY PRECIPITATION WITH SIGNIFICANT
IMPACTS INCREASING ACROSS THE NORTHERN MIDLANDS MAINLY FOR
FREEZING RAIN LATE THURSDAY NIGHT THROUGH FRIDAY. WILL POST WINTER
STORM WATCH...
THURSDAY...A STRONG STORM SYSTEM WILL DEVELOP OVER THE LOWER- MID
MISSISSIPPI VALLEY AS AN UPPER TROUGH DEEPENS ACROSS THE MIDDLE OF
THE COUNTRY. A WARM FRONT WILL DEVELOP ALONG THE GULF COAST STATES
AS THE FORMATION OF A SURFACE LOW OCCURS OVER EAST TEXAS/NORTHERN
LOUISIANA AND STRENGTHENING SOUTHERLY 850MB FLOW OFF THE GULF OF
MEXICO INCREASES MOISTURE ACROSS THE FORECAST AREA. ATMOSPHERIC
COLUMN WILL INITIALLY BE QUITE DRY ON THURSDAY WITH PWAT VALUES
LESS THAN A HALF INCH WITH SIGNIFICANT DRY AIR ABOVE 5000FT BUT
THE MOISTURE WILL INCREASE THROUGH THE DAY AS ISENTROPIC LIFT
DEVELOPS NORTH OF THE WARM FRONT AND SATURATES THE COLUMN. BY 00Z
FRIDAY THE PWAT VALUES WILL BE JUST UNDER 1 INCH.
PRECIPITATION ASSOCIATED WITH ISENTROPIC LIFT AND MAYBE A WEAK UPPER
DISTURBANCE IN THE SOUTHWESTERLY FLOW WILL LEAD TO INCREASING POPS
THROUGH THE DAY FROM SOUTHWEST TO NORTHEAST...ALTHOUGH THE LATEST
MODEL RUNS HAVE TRENDED A BIT SLOWER WITH THE ONSET. THERE MAY BE
SOME DIABATIC COOLING EFFECTS FROM PRECIPITATION FALLING INTO AN
INITIALLY DRY AIRMASS...FORECAST SURFACE WETBULB TEMPS ARE EXPECTED
TO BE ABOVE FREEZING...YIELDING LIQUID RAINFALL. TEMPERATURES WILL
BE SLOW TO RISE ON THURSDAY AND WILL LEAN TOWARDS THE COOLER
GUIDANCE GIVEN CLOUD COVER AND SOME DIABATIC COOLING WITH
PRECIPITATION.
THURSDAY NIGHT AND FRIDAY...SIGNIFICANT DEEPENING OF THE SURFACE LOW
OVER THE MISSISSIPPI VALLEY WILL OCCUR IN RESPONSE TO A NEGATIVE
TILTING OF THE UPPER TROUGH AS IT TRANSITIONS INTO A CLOSED LOW OVER
MS/AL. ISENTROPIC LIFT WILL STRENGTHEN OVER THE REGION THROUGH
FRIDAY MORNING AS THE WARM FRONT SLOWLY LIFTS NORTHWARD AND WILL
CARRY CATEGORICAL POPS. CONFLUENT 500MB FLOW OVER THE EASTERN OHIO
VALLEY AND NORTHEAST WILL RESULT IN A STRENGTHENING SURFACE RIDGE
OVER THE MID ATLANTIC AND COLD AIR DAMMING WILL DEVELOP ACROSS VA/NC
INTO THE NORTHERN PORTION OF THE FORECAST AREA THURSDAY NIGHT INTO
FRIDAY. WETBULB TEMPERATURES DROP ACROSS THE NORTHERN MIDLANDS
FALLING BELOW FREEZING BY EARLY FRIDAY MORNING. THIS WILL LIKELY
RESULT IN A PERIOD OF FREEZING RAIN IN THE NORTHERN MIDLANDS. THERE
REMAIN SOME DIFFERENCES AMONG THE GUIDANCE ON LOW LEVEL THERMAL
PROFILES WITH THE NAM/CANADIAN BEING COLDER THAN THE GFS WHICH LEADS
TO SOME UNCERTAINTY AS TO HOW FAR SOUTH THE FREEZING RAIN MAY BE.
COMPLEX STORM SYSTEM EVOLUTION ON FRIDAY SHOWS THE INITIAL
SURFACE LOW LIFTING NORTHEASTWARD INTO EASTERN TENNESSEE WITH A
TRANSITION TO A COASTAL LOW DEVELOPING SOMEWHERE OVER EASTERN
SOUTH CAROLINA BY 00Z SATURDAY.
RELATIVELY STEADY TEMPERATURES THURSDAY NIGHT WITH CLOUDS AND
PRECIPITATION ALTHOUGH TEMPERATURES WILL LIKELY FALL ACROSS THE
NORTHERN MIDLANDS. EXPECT A STRONG GRADIENT IN TEMPERATURES ON
FRIDAY AS SURFACE LOW APPROACHES AND WARM ADVECTION OCCURS ACROSS
THE SOUTHERN PART OF THE AREA WHILE THE WEDGE HOLDS STRONG ACROSS
THE NORTH...THOUGH TEMPERATURES UP NORTH SHOULD ALSO RISE A BIT
FRIDAY AFTERNOON.
THIS LOOKS TO BE A POTENTIALLY SIGNIFICANT QPF EVENT WITH LIQUID
ACCUMULATIONS OF A 0.50-1.00 INCH WITH ACCUMULATING FREEZING RAIN
ACROSS PARTS OF THE NORTHERN MIDLANDS COUNTIES. WILL INCLUDE SOME
LIGHT ICE ACCUMULATION ACROSS THE NORTHERN MIDLANDS WITH THIS
FORECAST ISSUANCE BUT WILL HOLD OFF ON ANY HEADLINES AND ALLOW
LATER SHIFTS TO VIEW NEW DATA AND ISSUE A WATCH FOR
LANCASTER/CHESTERFIELD IF NEEDED.
FRIDAY NIGHT AND SATURDAY...SURFACE LOW DEEPENS AND MOVES UP THE
COAST TO NEAR NORFOLK BY 12Z SATURDAY WHILE THE CLOSED UPPER LOW
SLOWLY MOVES OVER THE SOUTHERN APPALACHIANS BY SATURDAY MORNING. MID
LEVEL DRY SLOT FORECAST TO MOVE OVER THE FORECAST AREA FRIDAY NIGHT
INTO EARLY SATURDAY WHICH WILL RESULT IN MUCH LOWER POPS FRIDAY
NIGHT.
THE UPPER LOW WILL DRIFT EAST ACROSS THE CAROLINAS ON SATURDAY WITH
THE CORE OF THE COLD AIR ALOFT MOVING OVER THE FORECAST AREA WITH
500MB TEMPS AS COLD AS -26C TO -27C. THE AMOUNT OF MOISTURE
ASSOCIATED WITH THE UPPER LOW IS THE MAIN UNCERTAINTY AT THIS POINT
WITH THE NAM/CANADIAN SHOWING MUCH MORE SHALLOW MOISTURE COMPARED TO
THE GFS/ECMWF. CANNOT RULE OUT SOME RAIN/SNOW MIX ON SATURDAY
ACROSS THE AREA BUT POPS WILL BE LOW AND LIQUID ACCUMULATION IS
EXPECTED TO BE LIGHT...BUT ANY ACCUMULATION IS EXPECTED TO BE
LIGHT.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
MODELS ARE IN FAIRLY GOOD AGREEMENT AND CONTINUE TO COME TOWARD A
CONSENSUS WITH THE LOW PRESSURE SYSTEM CROSSING THE AREA FRIDAY
THROUGH SATURDAY. THE GFS IS SLIGHTLY FASTER THAN THE ECMWF.
THE STORM SYSTEM WILL TRACK ACROSS THE REGION FRIDAY PROVIDING
WIDESPREAD PRECIPITATION. THE AREA OF LOW PRESSURE SHOULD MOVE
EAST OF THE MIDLANDS FRIDAY NIGHT THEN TURN NORTHEASTWARD AND
MOVE ALONG TO THE MID ATLANTIC COAST SATURDAY. AS LOW PRESSURE
SYSTEM DEEPENS OFF THE NC/VA COAST LATE FRIDAY NIGHT...PARTIAL
THICKNESS SCHEMES SUGGEST WINTRY PRECIPITATION POSSIBLE ACROSS THE
NORTHERN AND WESTERN MIDLANDS AS WELL AS THE PIEDMONT...ALTHOUGH
MOISTURE MAY BE SHALLOW. ALTHOUGH QPF VALUES WILL BE LOW HAVE
REMAINED WITH THE POTENTIAL RAIN/SNOW MIXTURE ASSOCIATED WITH WRAP
AROUND MOISTURE. UNCERTAINTY REMAINS QUITE HIGH. HIGH PRESSURE AND
DRIER AIR WILL RETURN TO THE REGION FOR SUNDAY AND MONDAY WITH THE
NEXT LOW PRESSURE SYSTEM WILL PUSH A COLD FRONT TOWARD THE AREA
MONDAY NIGHT.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
AN UPPER DISTURBANCE PASSING THROUGH WILL CONTINUE TO PROVIDE SOME
LIGHT RAIN...POSSIBLY MIXED WITH LIGHT SLEET...IN THE NEAR TERM. NO
SLEET ACCUMULATION DUE TO TEMPERATURES WELL ABOVE FREEZING. CLOUD
BASES ARE ABOVE VFR LEVEL. PRECIPITATION EXPECTED TO DIMINISH OR
MOVE OUT OF THE REGION LATER THIS EVENING...WITH MID LEVEL
CLOUDINESS REMAINING IN PLACE THROUGH THE OVERNIGHT. AREA OF MVFR
CIGS TO THE NW OF OUR FORECAST AREA (FA)...EXPECTED TO REMAIN JUST
NW OF OUR FA OVERNIGHT. LIGHT WINDS. SOME LIGHT RAIN EXPECTED TO
DEVELOP LATE TONIGHT AND THURSDAY MORNING MAINLY TO OUR WEST IN
RESPONSE TO THE NEXT APPROACHING UPPER DISTURBANCE. THIS LIGHT RAIN
ACTIVITY AND ASSOCIATED MVFR CIGS COULD SHIFT EAST...AND AFFECT
AGS/DNL. MORE WIDESPREAD PRECIPITATION AND RESTRICTIONS FOR OUR FA
EXPECTED TO HOLD OFF UNTIL THURSDAY NIGHT AS MAIN UPPER ENERGY AND
SURFACE LOW MOVE IN.
EXTENDED AVIATION OUTLOOK....PRECIPITATION AND WIDESPREAD IFR TO
MVFR CONDITIONS EXPECTED THURSDAY NIGHT THROUGH SATURDAY. CURRENT
INDICATIONS ARE THAT THE PRECIPITATION WILL BE MAINLY IN THE FORM OF
RAIN AT OUR TERMINALS...WITH ANY SIGNIFICANT WINTER PRECIPITATION
MAINLY REMAINING JUST NORTH OF OUR TERMINALS. BREEZY CONDITIONS
POSSIBLE SATURDAY/SATURDAY NIGHT.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...WINTER STORM WATCH FROM LATE THURSDAY NIGHT THROUGH SATURDAY
EVENING FOR SCZ015-016.
&&
$$
AREA FORECAST DISCUSSION
National Weather Service Lincoln IL
1139 PM CST MON JAN 18 2016
.UPDATE...
ISSUED AT 900 PM CST MON JAN 18 2016
The strato-cumulus and flurries in the southeast counties has
nearly departed into Indiana as of 9 pm. The clouds in our western
counties are positioned on the north side of a surface high
pressure, centered in southern IL to eastern Arkansas. Those
clouds are not being handled well at all in the HRRR nor RAP.
Satellite trends show some dissipation on the outer edges of the
narrow band of clouds as it slowly drifts eastward. Will continue
with the trend that before sunrise, that band of clouds will
mostly dissipate as cirrus clouds stream into western IL.
Low temps tonight will be closely tied to how soon those low
clouds dissipate. We are currently forecasting temps to drop
another 7-9 degrees from current readings in our west and
southwest, but that would not occur if clouds linger as late as
sunrise. Will stay the course with low temps, assuming clearing,
and keep lows around 6-7F in our SW and S, and -1F to +1F from
Galesburg to Lacon.
Looking ahead, snowfall still looks on track to begin southwest of
Springfield late Tuesday afternoon, with the bulk of the snowfall
occurring between 6 pm and 3 am. Amounts should be mainly in the 1
to 3 inch range, with the higher amounts south of a line from
Springfield to Effingham. The wave looks progressive, with snow
ending before 6 am in all of our counties, including those
bordering Indiana.
Updates this evening were mainly to sky grids, and weather grids
for flurries in the SE. Updated forecast info is already
available.
&&
.SHORT TERM...(Tonight)
ISSUED AT 248 PM CST MON JAN 18 2016
A robust diurnal CU-field developed across central Illinois this
afternoon, mainly along and south of the I-72 corridor. Meanwhile,
a persistent band of low clouds extending from Minnesota into west-
central Illinois tried to push eastward, but generally stayed west
of a Macomb to Jacksonville line. The diurnal clouds will rapidly
dissipate toward sunset: however, the band of clouds further west
will likely persist into the evening. Models have not been picking
up on these clouds at all, with the HRRR 1-hour forecast suggesting
clear skies. Based on satellite loops, think they will inch
eastward into the Illinois River Valley over the next couple of
hours before gradually dissipating later in the evening. Will need
to monitor satellite trends closely to see if they spread further or
persist longer. At this time, will only bring them to a Galesburg
to just west of Springfield line this evening. Elsewhere, skies
will remain mostly clear through the night. Overnight low
temperatures will be in the single digits above zero across most of
the area, but will likely drop a couple degrees below zero across
the far north around Galesburg and Lacon.
.LONG TERM...(Tuesday through Monday)
ISSUED AT 248 PM CST MON JAN 18 2016
Arctic high pressure area will shift east of the CWA Tuesday and
allow a developing weather system in the southern plains to push
east and bring precip back into the area beginning late Tue
afternoon and continuing through Tue night, then ending Wed morning.
Temps thru the period will be cold enough for all snow, so question
will be how much snow and when will heaviest snow occur. The models
have trended slightly slower with the onset of the snow and this
makes sense given the current dryness of the lower layers and the
expected southeast winds tomorrow not bringing any moisture into the
area. So, believe snow will begin over most of the area after 6pm
tomorrow evening, though some light snow may begin in western IL
late tomorrow afternoon. Heaviest snowfall track should be from the
Jacksonville area to southeast IL, tomorrow evening through after
midnight. The main low will be tracking into AR late tomorrow night,
but system should be able to spread enough pcpn north into the area.
Models indicate good isentropic lift with this system with around
3g/kg of moisture being lifted. However, factors limiting the amount
of snowfall will be lack of low level moisture initially, system
will be weakening as it moves east, and system will be moving
through quickly. So snowfall thinking is 3-4 inches in western IL
will be the highest, decreasing to around 3 inches in the southeast,
and 2 to 2.5 inches along I-74. This matches up well with other
offices and thinking of the WWD graphics. Snow will continue into
Wed morning,but only in the east and southeastern parts of the CWA.
1/2 inch will still be possible in the Lawrenceville area before
ending by noon. Advisory will be likely in some part of the CWA, but
given most of the snow will be third period and still some
uncertainty on strength of system, will let overnight shift make
final decision on location of advisory.
A period of dry weather is then expected Wed night through Thursday
as this system pushes east and then next system moves out of the
plains toward the area. All models have finally come to some
agreement on the track of this next system and it appears that most
of the pcpn with it will be south of the CWA. Current forecasts show
that a chance of snow is possible in southeast IL Thur night only.
Otherwise, dry weather can be expected from Fri into Sunday. Then
Sunday night and Monday, models show a clipper system moving across
the northern third of the state. This will bring another shot of
pcpn to the northern/northeaster/and eastern parts of the CWA. P-
type will likely be snow, but with temps being above freezing during
the daytime periods, rain, or a mix of rain and snow is not out of
the question.
Temps will remain cold through Fri night given the continued Arctic
air over the area through tomorrow and then the clouds and pcpn
expected tomorrow night through Wed, and then again being north of
the Thur night/Fri weather system. Over the weekend the pattern will
become somewhat zonal and this should allow temps to warm back up to
normal or just above normal for Sun and Mon.
&&
.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
ISSUED AT 1139 PM CST MON JAN 18 2016
The band of low VFR clouds that was in western Illinois earlier
this evening has drifted eastward, extending from PIA to Lincoln
to DEC at 05z. At the same time, they have lowered slightly to
just into MVFR levels at 2700-2900 FT. In the last couple of
hours, satellite images has showed the band narrowing. The high
res models continue to show the MVFR clouds dissipating in the
next few hours. The subsidence inversion under the ridge axis
could counter some of that clearing, so will carry the MVFR clouds
for at least the next 3-4 hours of the TAF period, and update as
necessary.
Isentropic lift and warm advection ahead of the next system will
trigger mid and high clouds to begin overspreading our western
counties by early afternoon. Time height analysis in the NAM and
GFS point toward a period of stronger lift will begin by 01z near
SPI and expand eastward during the evening, reaching CMI and DEC
by 04z. The deeper moisture coincident with stronger omega will be
mainly closer to SPI and DEC, so have dropped them to IFR vis
during snowfall tomorrow evening. Snow could accumulate quickly,
based on moisture content of 3 g/kg mixing ratios, and moderately
strong isentropic lift on the 290K surface. Travel surface could
quickly become slippery Tuesday evening for all terminal sites.
Winds will generally be light and variable under the surface ridge
axis the rest of tonight, and even into tomorrow morning. Wind
directions will become southeast Tuesday afternoon as the surface
winds respond to the approaching cyclone.
&&
.ILX Watches/Warnings/Advisories...
NONE.
&&
$$
UPDATE...Shimon
SHORT TERM...Barnes
LONG TERM...Auten
AVIATION...Shimon
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
243 PM CST TUE JAN 19 2016
.SYNOPSIS...
ISSUED AT 243 PM CST TUE JAN 19 2016
A SHRTWV TROF ADVECTING THROUGH NW FLOW LEAD TO SNOW ACROSS THE
IOWA AND N MO THIS AFTERNOON. SNOWFALL TOTALS OF 1 TO 4 INCHES
HAVE BEEN REPORTED IN SW IA INTO S CENTRAL IA. THIS FEATURE WILL
MOVE TO THE EAST THROUGH THE REST OF TODAY. AS THE COLUMN BEGINS
TO SATURATE...SNOW WILL OVERSPREAD THE CWA THIS EVENING.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 243 PM CST TUE JAN 19 2016
MAIN FORECAST CONCERN FOR THE SHORT TERM IS THE SNOW THIS
AFTERNOON AND INTO THE EVENING. GUIDANCE AND OBSERVATIONAL TRENDS
SUGGESTS THAT HEAVIEST SNOW...4+ INCHES...WILL OCCUR JUST TO THE
SOUTH OF THE CWA. AS A RESULT...UPDATED SNOW TOTALS AND CURRENT
CHANGES TO THE FORECAST WILL RESULT IN THE ADDITION OF MCDONOUGH
COUNTY IN THE WS.Y. THE BEST CHANCE FOR 3+ INCHES WILL BE SOUTH OF
A LINE FROM MACOMB TO KEOSAUQUA.
HIRES GUIDANCE....SPECIFICALLY THE HRRR AND HIRES NMM KEEPS THE
HEAVIEST SNOW TO OUR SOUTH THIS EVENING. THIS LINES UP WITH AN
OMEGA SIGNAL IN THE DGZ AS WELL. IT APPEARS THAT LIGHT SNOW WILL
OVERSPREAD THE AREA FROM WEST TO EAST. NEAR 00Z...AS THE OMEGA
INCREASES ACROSS THE SOUTH...SNOW INTENSITY SHOULD PICK UP. AT
THIS TIME...THE VORT WILL BE QUICKLY MOVING THROUGH LEADING TO A
QUICK END TO THE SNOW FROM WEST TO EAST. THINK THAT MOST OF THE
SNOW WILL BE OVER AOA 06Z WED. A LOOK AT THE FORECAST PLUMES
SUGGESTS THAT THE HIGHEST CONFIDENCE FOR 3+ INCHES WILL BE ACROSS
OUR EXTREME SOUTH. SNOW TOTALS SHOULD RAPIDLY DECREASE AS YOU
MOVE NORTH OF HWY 34 CORRIDOR WITH THE QC SEEING AROUND AN INCH
TOTAL. THIS IS SUPPORTED BY THE HIRES GUIDANCE AND ENSEMBLE
OUTPUT.
PAST THIS..IT LOOKS LIKE SOME OF THE WARMEST TEMPS IN THE PAST
COUPLE OF DAYS WILL BE TOMORROW WITH NO CHANCE OF POPS.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 243 PM CST TUE JAN 19 2016
QUIET AND DRY CONDITIONS WILL BE SEEN ACROSS THE AREA WEDNESDAY
NIGHT THROUGH THURSDAY AS HIGH PRESSURE QUICKLY MOVES THROUGH THE
AREA. TEMPERATURES WILL AVERAGE BELOW NORMAL.
ON THURSDAY NIGHT...MAINLY DRY CONDITIONS ARE EXPECTED AS THE HIGH
MOVES INTO THE OHIO VALLEY. A WEAK DISTURBANCE MOVING THROUGH THE
UPPER MIDWEST MAY BRING SOME FLURRIES OR VERY LIGHT SNOW TO THE
HIGHWAY 20 CORRIDOR WEST OF DUBUQUE.
DRY CONDITIONS WILL THEN BE SEEN ACROSS THE AREA ON FRIDAY AS
ANOTHER HIGH PRESSURE BUILDS INTO THE MIDWEST. TEMPERATURES WILL BE
SLIGHTLY BELOW NORMAL.
FRIDAY NIGHT ON...
THE MODEL CONSENSUS HAS DRY CONDITIONS FRIDAY NIGHT THROUGH SUNDAY
AS HIGH PRESSURE MOVES INTO THE OHIO VALLEY. TEMPERATURES WILL
SLOWLY CLIMB TO ABOVE NORMAL ON SUNDAY. ATTENTION THEN TURNS TO A
POTENTIAL STORM SYSTEM.
SUNDAY NIGHT INTO MONDAY THE MODELS DIVERGE ON THEIR RESPECTIVE
SOLUTIONS. THE ECMWF IS DRY BUT THE GEM AND TO A MUCH LESSER EXTENT
THE GFS SUGGEST A WEAK STORM SYSTEM MOVING THROUGH THE AREA. GIVEN
THE CONSIDERABLE DIFFERENCES...THE MODEL CONSENSUS HAS SLIGHT CHANCE
POPS FOR SUNDAY NIGHT AND MONDAY.
MONDAY NIGHT AND TUESDAY THE MODEL CONSENSUS HAS DRY CONDITIONS AS
HIGH PRESSURE BUILDS INTO THE MIDWEST.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1133 AM CST TUE JAN 19 2016
VFR FLIGHT CONDITIONS TO DETERIORATE TO IFR AND POSSIBLY LIFR
WITH SNOW THROUGH THE EXTENDED PERIOD. THE FIRST SIX HOURS LOOK TO
BE VFR TO MVFR WITH SN SNEAKING IN ACROSS THE WEST AT CID.
CID...BRL AND MLI WILL LIKELY SEE ACCUMULATING SN. DO NOT HAVE
HIGH CONFIDENCE THAT DBQ WILL SEE ANY...SO KEPT VCSH. REGARDLESS
AFTER THE SYSTEM EXITS THE AREA THIS EVENING...LINGERING LLVL
MOISTURE WILL CAUSE CIGS AND VSBYS TO DROP IN THE AM. EXPECT IFR
CONDITIONS WITH POSSIBLE LIFR CONDITIONS AROUND 12Z WED.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR LEE-VAN
BUREN.
IL...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR HANCOCK-
MCDONOUGH.
MO...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR CLARK-
SCOTLAND.
&&
$$
SYNOPSIS...GIBBS
SHORT TERM...GIBBS
LONG TERM...08
AVIATION...GIBBS
AREA FORECAST DISCUSSION...UPDATED
NWS QUAD CITIES IA IL
1137 AM CST TUE JAN 19 2016
...18Z AVIATION UPDATE...
.UPDATE...
ISSUED AT 1018 AM CST TUE JAN 19 2016
CURRENT RADAR IMAGERY DEPICTS LIGHT SNOW ACROSS WESTERN IOWA
SLOWLY MAKING ITS WAY TO THE EAST. HIRES CAM GUIDANCE...ALONG WITH
THE RAP AND NAM SUGGEST THAT THE BEST FORCING IN THE DGZ OCCURS TO
THE SOUTH OF THE CWA. THIS IS CLOSE TO OUR SOUTHERNMOST TIER OF
COUNTIES. WITH ANY SMALL DIFFERENCES TO THIS TRACK...OUR SOUTHERN
COUNTIES COULD SEE EITHER MORE SNOW OR LESS SNOW. THIS...ALONG
WITH TIMING DURING THE RUSH HOUR IS ENOUGH TO WARRANT THE
ADVISORY STAYING IN THE SOUTH. NO CHANGES...OTHER THAN TIMING OF
PRECIP ONSET HAVE BEEN MADE.
&&
.SYNOPSIS...
ISSUED AT 345 AM CST TUE JAN 19 2016
LATEST ANALYSIS AT 2 AM SHOWS BEGINNINGS OF LIGHT SNOW DEVELOPING
IN NEBRASKA THAT IS A BIT TOO FAR NORTH OF MOST SOLUTIONS AND ALSO
A BIT SLOWER. SIGNIFICANT MID LEVEL CLOUDS ARE JUST TO THE SOUTHWEST
OF THE FORECAST AREA AND SHOULD OVERSPREAD MOST OF THE REGION BY
DAWN. AREA TEMPERATURES APPEAR TO HAVE STALLED AND VERY WELL MAY
BEGIN TO SLOWLY RISE THE NEXT SEVERAL HOURS AS CLOUDS THICKEN.
UPSTREAM ANALYSIS SUGGEST MOST OF ENERGY TO PASS TO THE SOUTH WITH
ALL PRECIPITATION ENDING BY 06Z TONIGHT. THEN SEASONABLY COLD AND
MOSTLY DRY TO DRY.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 345 AM CST TUE JAN 19 2016
SHORT TERM FORECAST CONFIDENCE ASSESSMENT...FAIR TO POOR OR BELOW
TO WELL BELOW NORMAL. MAIN ISSUE REMAINS SNOW TOTALS...AS DISCUSSED
PAST 2 DAYS...FORCING IS CLEARLY COMING IN SOUTH WITH IMPACTS TO
SNOW AMOUNTS AND LOWERING OF POPS NORTH/ALONG OF I-80. THIS MAY
STILL BE UNDERDONE. MOST SOLUTIONS TOO LOW CLOUD BASES TO OBSERVATIONS
AND TOO MUCH COVERAGE OF PRECIPITATION AND TOO FAR DISPLACED NORTH
MAKES THIS QUESTION LIKELY TO BE RESOLVED IN THE NEXT 6 TO 8 HOURS
OF EVEN LOWER AMOUNTS AND FURTHER SOUTH TRACK OF HEAVIER SNOW TOTALS.
TODAY...HAVE DELAYED AND LOWERED POPS WITH RISK POPS ARE STILL A BIT
TOO FAST BY COUPLE HOURS. HAVE TRIMMED QPF AND SNOW TOTALS BY 30+ PERCENT
NORTH HALF AND 20 TO 30 PERCENT SOUTH HALF. TRENDS SUGGEST THIS MAY
STILL NEED LOWERING BY SIMILAR PERCENTAGES FOR DAY SHIFT. MINOR CHANGES
TO HIGHS BETWEEN 12 NORTH TO AROUND 20 DEGREES SOUTH. SINCE ALREADY
HAVE A WINTER WEATHER ADVISORY FAR SW...WILL NOT CANCEL AT THIS TIME...BUT
THIS HEADLINE MAY BE DEEMED NOT NEEDED FOR AT LEAST SOME COUNTIES BY
LATE MORNING. ANY ACCUMULATING SNOWS LIKELY TO ARRIVE FAR SW SECTIONS
AROUND NOON. RAIN/SNOW RATIOS SUGGESTED TO BE AROUND 15-18 TO 1 SOUTH
TO 18 TO 20+ TO 1 FAR NORTH. WIND SHOULD NOT BE A FACTOR WITH 5 TO 10
MPH OUT OF THE SOUTHEAST TO RESULT IN NO DRIFTING ISSUES WHERE ACCUMULATING
SNOW FALL.
TONIGHT...AGAIN LOWERED AMOUNTS IN EVENING BY AROUND 30 PERCENT NORTH
HALF AND 20 TO 30 SOUTH HALF. SNOW TOTALS FOR THIS EVENT SHOULD RANGE
FROM A HALF INCH OR LESS ALONG AND NORTH OF HIGHWAY 30. BETWEEN A HALF
INCH TO 1.5 INCHES FROM HIGHWAY 30 TO HIGHWAY 34. THE LOCATIONS VERY
CLOSE TO MISSOURI BORDER AND SOUTH ARE MOST LIKELY TO SEE 2+ INCHES
WITH LOCALLY 3 TO 4 INCHES POSSIBLE. AGAIN...TRENDS DO SUGGEST ANY
3 PLUS INCHES MAY SLIDE A BIT FURTHER SOUTH OUT OF THE FORECAST AREA
WHICH SHOULD BE KNOWN BY NLT LATE MORNING.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 345 AM CST TUE JAN 19 2016
FORECAST CONCERNS TODAY ARE FOCUSED ON TEMPERATURES WITH NO MAJOR
SYSTEMS LOOKING TO IMPACT THE LOCAL AREA THROUGH THE NEXT WEEK.
MODELS ARE IN GOOD AGREEMENT WHEN LOOKING AT THE LARGE SCALE PATTERN
SO CONFIDENCE IS FAIRLY DECENT IN THE FORECAST. THAT BEING
SAID...MINOR DISCREPANCIES IN DETAILS IN THE MODELS LEAD TO SOME
UNCERTAINTY ON TEMPERATURES THROUGHOUT THE WEEK.
BEGINNING ON WEDNESDAY...THE MID-LEVEL SHORTWAVE TROUGH THAT WILL
BRING THE SNOW TO THE AREA THROUGH TONIGHT SHOULD BE EXITING THE
REGION WITH NO ACCUMULATING SNOW EXPECTED ANYWHERE ACROSS THE AREA
AFTER 12Z. FORECAST SOUNDINGS DO SHOW A RATHER THICK STRATUS LAYER
REMAINING OVER THE AREA IN THE WAKE OF THIS SYSTEM. DID CONTEMPLATE
ADDING IN MENTION OF FLURRIES FOR WEDNESDAY MORNING AS SATURATION
EXTENDS FROM THE SURFACE UP THROUGH AROUND 7K FEET...WHILE THIS
LAYER LOOKS TO BE NEARLY ISOTHERMAL VERY NEAR -12C TO BE COLD ENOUGH
FOR FLURRIES RATHER THAN ANY DRIZZLE. THE LIFT SEEN IN THIS LAYER IS
VERY WEAK THOUGH SO HELD OFF INCLUDING FLURRIES IN THE FORECAST.
WARM AIR ADVECTION WILL BE ONGOING THROUGH THE DAY WEDNESDAY AS
850MB TEMPERATURES WILL IMPROVE SIGNIFICANTLY. AFTER LOOKING TO BE
FROM 08C TO 12C ACROSS THE FORECAST AREA AT 12Z...THE WARMING LOOKS
TO BRING THE AREA TO A RANGE FROM NEAR 0C TO 08C BY 21/00Z. DESPITE
THE WARMING...BELIEVE THE THICK CLOUDS WILL STAY OVER THE AREA
THROUGH MUCH OF THE DAY SO WENT A BIT COOLER FOR HIGHS
WEDNESDAY...IN THE 20S. THE FORECAST IS EXPECTING THE CLOUDS TO
STICK AROUND WEDNESDAY NIGHT...WHICH WILL HELP KEEP TEMPERATURES
FROM FALLING TOO FAR DESPITE PRETTY LIGHT WINDS.
THERE IS A SYSTEM CURRENTLY OFF THE PACIFIC COAST...WHICH WILL MOVE
ONSHORE TONIGHT AND MOVE INTO THE CENTRAL PLAINS THROUGH WEDNESDAY
NIGHT. THE MODELS CONTINUE TO KEEP THIS SYSTEM WELL SOUTH OF THE
AREA SO HAVE HIGH CONFIDENCE ON THE DRY FORECAST FOR
THURSDAY/THURSDAY NIGHT. WITH THE SYSTEM STAYING SOUTH OF THE LOCAL
AREA...COLDER AIR WILL TAKE RESIDENCE FOR A SHORT PERIOD OF TIME.
COLDER BEING A RELATIVE TERM AS 850MB TEMPERATURES BOTTOM OUT AROUND
-9C WHICH IS WELL WARMER THAN WHAT WE HAVE BEEN EXPERIENCING THE
PAST FEW DAYS /DOWN TO NEAR -22C. DETAILS IN THE MODELS ARE GIVING
AN UNCLEAR SIGNAL OF WHERE TEMPERATURES WILL END UP THURSDAY AND
FRIDAY. USED A GENERAL BLEND FROM THE GUIDANCE...AND HAVE HIGHS IN
THE MID 20S...TO LOW 30S. RIDGING BUILDS INTO THE REGION FOR THE
WEEKEND WITH TEMPERATURES MODERATING TO ABOVE FREEZING ACROSS THE
ENTIRE FORECAST AREA BY SUNDAY. THE SOUTHERN PORTIONS OF THE
FORECAST AREA MAY EVEN GET CLOSE TO 40. THERE HAS BEEN A WEAK SIGNAL
IN THE PAST FEW MODEL RUNS OF LIGHT PRECIPITATION SUNDAY AND SUNDAY
NIGHT AS A WEAK SHORTWAVE MOVES INTO THE AREA...BUT THE TREND HAS
BEEN WEAKER WITH THIS SIGNAL AS DAYS HAVE PASSED SO PRECIPITATION
TRENDS HAVE BEEN TO GO LOWER AND THIS TREND CONTINUED FOR THIS
FORECAST CYCLE. A BETTER CHANCE FOR PRECIPITATION IS LOOKING TO COME
ON MONDAY...YET THERE ARE FAIRLY SIGNIFICANT DIFFERENCES BETWEEN THE
LONG RANGE MODELS WITH THE TIMING AND LOCATION OF THIS SYSTEM AS IT
MOVES ACROSS THE CENTRAL PART OF THE COUNTRY SO PRECIPITATION
CHANCES FOR THE MONDAY TIME-FRAME WILL LIKELY BE CHANGING IN LATER
FORECASTS AS THIS BECOMES MORE CLEAR. THAT BEING SAID...THIS WOULD
BE A LIGHT PRECIPITATION EVENT SO NO MAJOR SNOW OR RAIN AMOUNTS ARE
EXPECTED.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1133 AM CST TUE JAN 19 2016
VFR FLIGHT CONDITIONS TO DETERIORATE TO IFR AND POSSIBLY LIFR
WITH SNOW THROUGH THE EXTENDED PERIOD. THE FIRST SIX HOURS LOOK TO
BE VFR TO MVFR WITH SN SNEAKING IN ACROSS THE WEST AT CID.
CID...BRL AND MLI WILL LIKELY SEE ACCUMULATING SN. DO NOT HAVE
HIGH CONFIDENCE THAT DBQ WILL SEE ANY...SO KEPT VCSH. REGARDLESS
AFTER THE SYSTEM EXITS THE AREA THIS EVENING...LINGERING LLVL
MOISTURE WILL CAUSE CIGS AND VSBYS TO DROP IN THE AM. EXPECT IFR
CONDITIONS WITH POSSIBLE LIFR CONDITIONS AROUND 12Z WED.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR LEE-VAN
BUREN.
IL...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR HANCOCK.
MO...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR CLARK-
SCOTLAND.
&&
$$
UPDATE...GIBBS
SYNOPSIS...NICHOLS
SHORT TERM...NICHOLS
LONG TERM...BROOKS
AVIATION...GIBBS
AREA FORECAST DISCUSSION...UPDATED
NWS QUAD CITIES IA IL
1019 AM CST TUE JAN 19 2016
.UPDATE...
ISSUED AT 1018 AM CST TUE JAN 19 2016
CURRENT RADAR IMAGERY DEPICTS LIGHT SNOW ACROSS WESTERN IOWA
SLOWLY MAKING ITS WAY TO THE EAST. HIRES CAM GUIDANCE...ALONG WITH
THE RAP AND NAM SUGGEST THAT THE BEST FORCING IN THE DGZ OCCURS TO
THE SOUTH OF THE CWA. THIS IS CLOSE TO OUR SOUTHERNMOST TIER OF
COUNTIES. WITH ANY SMALL DIFFERENCES TO THIS TRACK...OUR SOUTHERN
COUNTIES COULD SEE EITHER MORE SNOW OR LESS SNOW. THIS...ALONG
WITH TIMING DURING THE RUSH HOUR IS ENOUGH TO WARRANT THE
ADVISORY STAYING IN THE SOUTH. NO CHANGES...OTHER THAN TIMING OF
PRECIP ONSET HAVE BEEN MADE.
&&
.SYNOPSIS...
ISSUED AT 345 AM CST TUE JAN 19 2016
LATEST ANALYSIS AT 2 AM SHOWS BEGINNINGS OF LIGHT SNOW DEVELOPING
IN NEBRASKA THAT IS A BIT TOO FAR NORTH OF MOST SOLUTIONS AND ALSO
A BIT SLOWER. SIGNIFICANT MID LEVEL CLOUDS ARE JUST TO THE SOUTHWEST
OF THE FORECAST AREA AND SHOULD OVERSPREAD MOST OF THE REGION BY
DAWN. AREA TEMPERATURES APPEAR TO HAVE STALLED AND VERY WELL MAY
BEGIN TO SLOWLY RISE THE NEXT SEVERAL HOURS AS CLOUDS THICKEN.
UPSTREAM ANALYSIS SUGGEST MOST OF ENERGY TO PASS TO THE SOUTH WITH
ALL PRECIPITATION ENDING BY 06Z TONIGHT. THEN SEASONABLY COLD AND
MOSTLY DRY TO DRY.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 345 AM CST TUE JAN 19 2016
SHORT TERM FORECAST CONFIDENCE ASSESSMENT...FAIR TO POOR OR BELOW
TO WELL BELOW NORMAL. MAIN ISSUE REMAINS SNOW TOTALS...AS DISCUSSED
PAST 2 DAYS...FORCING IS CLEARLY COMING IN SOUTH WITH IMPACTS TO
SNOW AMOUNTS AND LOWERING OF POPS NORTH/ALONG OF I-80. THIS MAY
STILL BE UNDERDONE. MOST SOLUTIONS TOO LOW CLOUD BASES TO OBSERVATIONS
AND TOO MUCH COVERAGE OF PRECIPITATION AND TOO FAR DISPLACED NORTH
MAKES THIS QUESTION LIKELY TO BE RESOLVED IN THE NEXT 6 TO 8 HOURS
OF EVEN LOWER AMOUNTS AND FURTHER SOUTH TRACK OF HEAVIER SNOW TOTALS.
TODAY...HAVE DELAYED AND LOWERED POPS WITH RISK POPS ARE STILL A BIT
TOO FAST BY COUPLE HOURS. HAVE TRIMMED QPF AND SNOW TOTALS BY 30+ PERCENT
NORTH HALF AND 20 TO 30 PERCENT SOUTH HALF. TRENDS SUGGEST THIS MAY
STILL NEED LOWERING BY SIMILAR PERCENTAGES FOR DAY SHIFT. MINOR CHANGES
TO HIGHS BETWEEN 12 NORTH TO AROUND 20 DEGREES SOUTH. SINCE ALREADY
HAVE A WINTER WEATHER ADVISORY FAR SW...WILL NOT CANCEL AT THIS TIME...BUT
THIS HEADLINE MAY BE DEEMED NOT NEEDED FOR AT LEAST SOME COUNTIES BY
LATE MORNING. ANY ACCUMULATING SNOWS LIKELY TO ARRIVE FAR SW SECTIONS
AROUND NOON. RAIN/SNOW RATIOS SUGGESTED TO BE AROUND 15-18 TO 1 SOUTH
TO 18 TO 20+ TO 1 FAR NORTH. WIND SHOULD NOT BE A FACTOR WITH 5 TO 10
MPH OUT OF THE SOUTHEAST TO RESULT IN NO DRIFTING ISSUES WHERE ACCUMULATING
SNOW FALL.
TONIGHT...AGAIN LOWERED AMOUNTS IN EVENING BY AROUND 30 PERCENT NORTH
HALF AND 20 TO 30 SOUTH HALF. SNOW TOTALS FOR THIS EVENT SHOULD RANGE
FROM A HALF INCH OR LESS ALONG AND NORTH OF HIGHWAY 30. BETWEEN A HALF
INCH TO 1.5 INCHES FROM HIGHWAY 30 TO HIGHWAY 34. THE LOCATIONS VERY
CLOSE TO MISSOURI BORDER AND SOUTH ARE MOST LIKELY TO SEE 2+ INCHES
WITH LOCALLY 3 TO 4 INCHES POSSIBLE. AGAIN...TRENDS DO SUGGEST ANY
3 PLUS INCHES MAY SLIDE A BIT FURTHER SOUTH OUT OF THE FORECAST AREA
WHICH SHOULD BE KNOWN BY NLT LATE MORNING.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 345 AM CST TUE JAN 19 2016
FORECAST CONCERNS TODAY ARE FOCUSED ON TEMPERATURES WITH NO MAJOR
SYSTEMS LOOKING TO IMPACT THE LOCAL AREA THROUGH THE NEXT WEEK.
MODELS ARE IN GOOD AGREEMENT WHEN LOOKING AT THE LARGE SCALE PATTERN
SO CONFIDENCE IS FAIRLY DECENT IN THE FORECAST. THAT BEING
SAID...MINOR DISCREPANCIES IN DETAILS IN THE MODELS LEAD TO SOME
UNCERTAINTY ON TEMPERATURES THROUGHOUT THE WEEK.
BEGINNING ON WEDNESDAY...THE MID-LEVEL SHORTWAVE TROUGH THAT WILL
BRING THE SNOW TO THE AREA THROUGH TONIGHT SHOULD BE EXITING THE
REGION WITH NO ACCUMULATING SNOW EXPECTED ANYWHERE ACROSS THE AREA
AFTER 12Z. FORECAST SOUNDINGS DO SHOW A RATHER THICK STRATUS LAYER
REMAINING OVER THE AREA IN THE WAKE OF THIS SYSTEM. DID CONTEMPLATE
ADDING IN MENTION OF FLURRIES FOR WEDNESDAY MORNING AS SATURATION
EXTENDS FROM THE SURFACE UP THROUGH AROUND 7K FEET...WHILE THIS
LAYER LOOKS TO BE NEARLY ISOTHERMAL VERY NEAR -12C TO BE COLD ENOUGH
FOR FLURRIES RATHER THAN ANY DRIZZLE. THE LIFT SEEN IN THIS LAYER IS
VERY WEAK THOUGH SO HELD OFF INCLUDING FLURRIES IN THE FORECAST.
WARM AIR ADVECTION WILL BE ONGOING THROUGH THE DAY WEDNESDAY AS
850MB TEMPERATURES WILL IMPROVE SIGNIFICANTLY. AFTER LOOKING TO BE
FROM 08C TO 12C ACROSS THE FORECAST AREA AT 12Z...THE WARMING LOOKS
TO BRING THE AREA TO A RANGE FROM NEAR 0C TO 08C BY 21/00Z. DESPITE
THE WARMING...BELIEVE THE THICK CLOUDS WILL STAY OVER THE AREA
THROUGH MUCH OF THE DAY SO WENT A BIT COOLER FOR HIGHS
WEDNESDAY...IN THE 20S. THE FORECAST IS EXPECTING THE CLOUDS TO
STICK AROUND WEDNESDAY NIGHT...WHICH WILL HELP KEEP TEMPERATURES
FROM FALLING TOO FAR DESPITE PRETTY LIGHT WINDS.
THERE IS A SYSTEM CURRENTLY OFF THE PACIFIC COAST...WHICH WILL MOVE
ONSHORE TONIGHT AND MOVE INTO THE CENTRAL PLAINS THROUGH WEDNESDAY
NIGHT. THE MODELS CONTINUE TO KEEP THIS SYSTEM WELL SOUTH OF THE
AREA SO HAVE HIGH CONFIDENCE ON THE DRY FORECAST FOR
THURSDAY/THURSDAY NIGHT. WITH THE SYSTEM STAYING SOUTH OF THE LOCAL
AREA...COLDER AIR WILL TAKE RESIDENCE FOR A SHORT PERIOD OF TIME.
COLDER BEING A RELATIVE TERM AS 850MB TEMPERATURES BOTTOM OUT AROUND
-9C WHICH IS WELL WARMER THAN WHAT WE HAVE BEEN EXPERIENCING THE
PAST FEW DAYS /DOWN TO NEAR -22C. DETAILS IN THE MODELS ARE GIVING
AN UNCLEAR SIGNAL OF WHERE TEMPERATURES WILL END UP THURSDAY AND
FRIDAY. USED A GENERAL BLEND FROM THE GUIDANCE...AND HAVE HIGHS IN
THE MID 20S...TO LOW 30S. RIDGING BUILDS INTO THE REGION FOR THE
WEEKEND WITH TEMPERATURES MODERATING TO ABOVE FREEZING ACROSS THE
ENTIRE FORECAST AREA BY SUNDAY. THE SOUTHERN PORTIONS OF THE
FORECAST AREA MAY EVEN GET CLOSE TO 40. THERE HAS BEEN A WEAK SIGNAL
IN THE PAST FEW MODEL RUNS OF LIGHT PRECIPITATION SUNDAY AND SUNDAY
NIGHT AS A WEAK SHORTWAVE MOVES INTO THE AREA...BUT THE TREND HAS
BEEN WEAKER WITH THIS SIGNAL AS DAYS HAVE PASSED SO PRECIPITATION
TRENDS HAVE BEEN TO GO LOWER AND THIS TREND CONTINUED FOR THIS
FORECAST CYCLE. A BETTER CHANCE FOR PRECIPITATION IS LOOKING TO COME
ON MONDAY...YET THERE ARE FAIRLY SIGNIFICANT DIFFERENCES BETWEEN THE
LONG RANGE MODELS WITH THE TIMING AND LOCATION OF THIS SYSTEM AS IT
MOVES ACROSS THE CENTRAL PART OF THE COUNTRY SO PRECIPITATION
CHANCES FOR THE MONDAY TIME-FRAME WILL LIKELY BE CHANGING IN LATER
FORECASTS AS THIS BECOMES MORE CLEAR. THAT BEING SAID...THIS WOULD
BE A LIGHT PRECIPITATION EVENT SO NO MAJOR SNOW OR RAIN AMOUNTS ARE
EXPECTED.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 537 AM CST TUE JAN 19 2016
CLOUDS WILL THICKEN AND LOWER THROUGH THE DAY WITH MVFR CONDITIONS
POSSIBLE AT BRL TERMINAL IN LIGHT SNOW BY 19/21Z DUE TO SNOW. THE
REMAINING TERMINALS WILL BECOME MVFR BY 20/03Z DUE TO RISK OF LIGHT
SNOW AND ALSO LOWERING CLOUDS. IFR CONDITIONS MAY BE POSSIBLE AT
ALL THE TERMINALS DUE TO LOW CLOUDS AND FOG AFTER 20/09Z.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR LEE-VAN
BUREN.
IL...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR HANCOCK.
MO...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR CLARK-
SCOTLAND.
&&
$$
UPDATE...GIBBS
SYNOPSIS...NICHOLS
SHORT TERM...NICHOLS
LONG TERM...BROOKS
AVIATION...NICHOLS
AREA FORECAST DISCUSSION
NWS GOODLAND KS
418 PM MST WED JAN 20 2016
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 132 PM MST WED JAN 20 2016
WV IMAGERY AND RAP H5/H7 ANALYSIS SHOWS TWO SHORTWAVE TROUGHS
IMPACTING THE CENTRAL ROCKIES AND PLAINS. THE STRONGER CLOSED CENTER
JUST EAST OF OUR CWA OVER NORTH CENTRAL KANSAS AND HAS DEEPENED
THROUGH MIDDAY. THE SECOND IS ENTERING EASTERN COLORADO. BETWEEN
THESE FEATURES THERE IS A SHORTWAVE RIDGE AND REGION OF
DRY/SUBSIDENT AIR APPARENT ON WV IMAGERY. AT THE SURFACE...A SURFACE
TROUGH IS IN PLACE OVER EASTERN COLORADO AND WHERE SKIES HAVE
CLEARED TEMPS HAVE WARMED IN TO THE 40S/50S. OVER OUR CWA (EAST OF
TROUGH AXIS) EXTENSIVE CLOUD COVER HAS SIGNIFICANTLY LIMITED HEATING
AND SEVERAL UPDATES TO HIGH TEMPS WERE WARRANTED EARLIER TODAY.
THIS AFTERNOON-THURSDAY...FOCUS CONTINUES TO BE ON POTENTIAL FOR
SNOW ACROSS OUR CWA. RADAR IS SHOWING SIGNS OF INCREASE IN
REFLECTIVITY IN OUR EASTERN CWA AND HILL CITY HAS STARTED TO REPORT
LIGHT SNOW. THIS CORRELATES WITH OF STRONG VORTICITY NEAR CLOSED LOW
CENTER AND BETTER MID LEVEL MOISTURE IS BEGINNING TO FILL IT. TREND
WILL BE FOR THIS CENTER TO ROTATE NORTH AND EAST TONIGHT BEFORE
SLIDING WELL EAST OF OUR CWA. AN ELEVATED BAROCLINIC ZONE/REGION OF
WEAK FRONTOGENESIS WILL DEVELOP AS THESE SHORTWAVE INTERACT AND PLACE
THE NORTHERN HALF OF OUR CWA IN A FAVORABLE LOCATION FOR POSSIBLE
LIGHT SNOW DEVELOPMENT BY THURSDAY MORNING. THE LIMITING FACTOR WILL
BE MOISTURE ADVECTION AS BOTH SHORTWAVE WILL TEND TO CUT OFF GULF
MOISTURE AND MODELS HAVE GENERALLY LIMITED QPF OVER OUR CWA
ACCORDINGLY. IN THE MEAN TIME...THE DRY/SUBSIDENT REGION BETWEEN
FEATURES MAY LIMIT ANY SNOW DEVELOPMENT IN OUR SOUTH.
I FAVORED THE EASTERN/NORTHEAST PART OF OUR CWA TONIGHT AND
THURSDAY MORNING FOR HIGHEST POPS. SNOW TOTALS SHOULD GENERALLY
RANGE 0.5-1" THOUGH IF THE EASTERN SHORTWAVE WERE TO REMAIN CLOSER
TO OUR CWA WE MAY HAVE A ROW OF COUNTIES RECEIVE AROUND 2" WHEN ALL
IS SAID AND DONE. ALL SNOWFALL SHOULD QUICKLY DISSIPATE/TRANSITION
EASTWARD AS THE RESULTING COMBINED TROUGH SHIFTS EAST AND RIDGING
BUILDS INTO OUR CWA THURSDAY AFTERNOON.
MODELS CONTINUE TO SHOW STRONGER BL WINDS DEVELOPING ON BACK SIDE OF
UPPER LOW AS THE TWO SHORTWAVES MERGE AND POST FRONTAL PRESSURE
GRADIENT INCREASES. LOCATION OF STRONGEST WINDS ACTUALLY CORRELATES
WITH MOST LIKELY LOCATION OF DRY SLOT DEVELOPMENT AND ABOVE
FREEZING TEMPERATURES DURING THE DAY THURSDAY. MIXING MAY BE LIMITED
IN LOCATIONS WITH CLOUD COVER/SNOW AND BL WINDS ARE LESS TO THE
NORTHEAST WHERE SNOWFALL IS MOST LIKELY. SINCE STRONGEST WINDS ARE
UNLIKELY TO BE LOCATED WITH BETTER SNOW CHANCES AND ACCUMULATIONS
ARE LIGHT I DID NOT SEE THE NEED TO KEEP BLOWING SNOW IN THE
FORECAST. AT MOST WE MAY SEE A BRIEF PERIOD OF DRIFTING SNOW AS SNOW
WINDS DOWN BEFORE TEMPS INCREASE TO FREEZING (OR WARMER). ANY
DRIFTING WOULD BE MINOR CONSIDERING AMOUNTS WE ARE DEALING WITH AS
WELL AS PEAK GUSTS IN THE REGION OF BETTER LIGHT SNOW ACCUMULATIONS
20-25 MPH.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 132 PM MST WED JAN 20 2016
THERE ARE A COUPLE OF FORECAST CONCERNS IN THE LONG TERM PERIOD.
FIRST IS THE TEMPERATURE GRADIENT ACROSS THE FORECAST AREA
THROUGH THE END OF THE WEEK AND INTO THE WEEKEND AS COOLER AIR
MOVES EAST AND WARMER DOWNSLOPING CONDITIONS OCCUR OVER THE WEST.
SECOND IS THE POSSIBILITY AND TYPE OF PRECIPITATION LATE SUNDAY
THROUGH EARLY MONDAY MORNING AS THE WARM AND DRY PATTERN
TRANSITIONS BRIEFLY BACK TO A COOLER AND MORE ACTIVE PATTERN AS A
SERIES OF DISTURBANCES MOVES ACROSS THE REGION LATE IN THE WEEKEND
THROUGH EARLY NEXT WEEK.
THE UPPER RIDGE MOVES EAST OVER THE HIGH PLAINS ON THURSDAY NIGHT
THROUGH FRIDAY NIGHT AND CONTINUES OVER THE EASTERN PLAINS STATES
ON SATURDAY. THE COOLER AREA OF HIGH PRESSURE AT THE SURFACE MOVES
INTO THE PLAINS STATES BY FRIDAY...WITH A LEE TROUGH DEEPENING
ALONG THE FRONT RANGE IN RESPONSE TO THE FLATTENING UPPER FLOW AS
AS SEVERAL SHORT WAVE TROUGHS MOVE THROUGH THE UPPER FLOW
SATURDAY NIGHT AHEAD OF THE NEXT MAIN UPPER TROUGH AXIS. THIS WILL
KEEP THE COOLER AIR OVER THE FAR EASTERN SECTIONS OF THE FORECAST
AREA AS THE WESTERN SECTIONS WARM UP. THE THURSDAY NIGHT THROUGH
SATURDAY NIGHT TIME PERIOD WILL STAY DRY AS A RESULT. HOWEVER...THE
TEMPERATURE GRADIENT ACROSS MY FORECAST AREA IS USUALLY MORE
DRAMATIC THAN DEPICTED BY ANY MODEL SOLUTIONS AND HAVE THEREFORE
TRIED TO GO TOWARDS THE WARM END OF GUIDANCE OVER THE WEST AND
TOWARDS THE COOL END OF GUIDANCE OVER THE EAST TO MAKE THE
GRADIENT MORE DRAMATIC. ANY RELUCTANCE OF LOW CLOUD COVER TO
DISSIPATE OVER THE EASTERN SECTIONS...AS HAS BEEN THE CASE OVER
RECENT DAYS...WILL ALSO ACT TO INCREASE THE TEMPERATURE GRADIENT.
A SURFACE LOW CONSOLIDATES OVER THE NORTHERN PANHANDLE REGION ON
SUNDAY...LIFTING INTO MISSOURI BY MONDAY MORNING ALONG THE
FRONTAL BOUNDARY EXTENDING FROM THE GREAT LAKES INTO THE SOUTHERN
PLAINS AS THE MAIN UPPER TROUGH AXIS MOVES EAST OF THE ROCKIES BY
SUNDAY AFTERNOON. A DEEPER AND BROADER UPPER TROUGH IS EVENTUALLY
CARVED OUT OVER MUCH OF THE UNITED STATES EAST OF THE ROCKIES BY
MONDAY NIGHT AS ANOTHER RIDGE MOVES INTO PLACE OVER THE WEST
COAST. THIS WILL OPEN THE DOOR TO COLDER AIR DIVING SOUTH INTO THE
PLAINS STATES ON MONDAY. WITH THE TRACK OF THE SURFACE LOW
REMAINING WELL SOUTH OF THE FORECAST AREA AND LITTLE MOISTURE TO
WORK WITH...EXPECT ONLY A SLIGHT CHANCE OF LIGHT RAIN OR SNOW
LATE SUNDAY TRANSITIONING TO ALL SNOW SUNDAY EVENING...WITH
MINIMAL ACCUMULATIONS POSSIBLE MAINLY ACROSS SOUTHERN NEBRASKA AND
EASTERN COLORADO.
THE UPPER WEST COAST RIDGE FLATTENS AND MOVES EAST OVER THE
MOUNTAINOUS WEST BETWEEN SUNDAY AND WEDNESDAY WITH ANOTHER LEE
TROUGH DEEPENING ALONG THE FRONT RANGE. WESTERLY NEAR SURFACE
FLOW WILL PRODUCE DRYING CONDITIONS AND WARMING TEMPERATURES
AGAIN OVER THE FORECAST AREA ON TUESDAY AND WEDNESDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 411 PM MST WED JAN 20 2016
VFR CONDITIONS WILL RETURN EARLY THIS EVENING AT KGLD AND KMCK AS
A DISTURBANCE EXITS THE AREA. HOWEVER, MVFR CONDITIONS WILL MOVE
BACK INTO KMCK BY MID EVENING AND AROUND MIDNIGHT AT KGLD AS
CLOUDS INCREASE WITH THE NEXT DISTURBANCE. FORECAST SOUNDINGS
SATURATE ENOUGH FOR LIGHT SNOW OVERNIGHT AND THURSDAY MORNING.
LIGHT SNOW SHOULD TAPER OFF BY MID AFTERNOON BUT CONDITIONS
SHOULD REMAIN MVFR.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...LOCKHART
AVIATION...FS
AREA FORECAST DISCUSSION
National Weather Service Dodge City KS
515 PM CST WED JAN 20 2016
...Updated Aviation Discussion...
.SHORT TERM...(THIS EVENING THROUGH Thursday)
ISSUED AT 1245 PM CST WED JAN 20 2016
Precip chances pick up tonight as short range models indicate a
strong H5 vort maxima associated with a deepening upper level
shortwave trough, digging southeast across the Four Corners Region
into the South Plains of west Texas tonight. As the upper level
system approaches, surface low pressure in southeast Colorado will
begin moving southeast into the Texas Panhandle as a strong cold
front starts pushing southeast into western Kansas overnight.
Meanwhile, a prevailing southeasterly upslope flow will continue
to draw moisture up into central and eastern portions of southwest
Kansas with surface dewpoints climbing up into the upper 20s(F) to
near 30F. Although the flow aloft will remain fairly weak, enough
low level forcing/lift will be present within the upslope flow
just ahead of the approaching front to support precip development
as the lower/mid levels become more saturated. Precip type may be
mixed through late this afternoon as this morning`s 12Z sounding
indicated a shallow layer of air a little above freezing in the
lower levels. Based on radar trends and observations, periods of
freezing drizzle can be expected through early this evening with
the possibility of snow mixed in as the day progresses. The best
chance for snow will be across portions of central Kansas where
the best moisture will reside with any snow accumulations
generally around a trace to 1 inch as the system quickly moves
through. However, locally higher amounts nearing 2 inches cannot
be ruled out.
A cold front will push through western Kansas overnight turning
winds northerly and allowing colder air to filter southward into the
high plains toward daybreak Thursday. Look for lows generally down
into the 20s(F) tonight with near 30F possible closer to the
Oklahoma border. Colder air will continue to surge southward into
western Kansas during the day Thursday behind the cold front
dipping further south into north Texas. The NAM/GFS show H85
temperatures ranging from around 5C below across central Kansas
Thursday afternoon to near 0C in extreme southwest Kansas.
Considering how long increased cloud cover persists through the
day, highs may struggle to reach the lower 30s(F) in central
Kansas with highs pushing 40F in extreme southwest Kansas.
.LONG TERM...(Thursday NIGHT THROUGH Wednesday)
ISSUED AT 200 PM CST WED JAN 20 2016
Medium range models indicate an amplified upper level ridge of
high pressure moving eastward across the Central and Southern
Rockies Friday, then breaking down as it shifts further east into
the Central Plains Saturday. Associated with a weak flow aloft
and a lack of moisture in the lower/mid levels, no precip can be
expected across western Kansas through early Sunday. Precip
chances return to western Kansas Sunday night as an upper level
shortwave trough kicks out of the Central and Southern Rockies
into the Western High Plains. Although an attendant cold front is
projected to push through western Kansas sometime late Sunday, it
is too early to determine the impacts this system will have in
regards to precip type.
A gradual warming trend will begin Friday as the aforementioned
upper level ridge moves east across the Central and Southern
Rockies into the Western High Plains. Surface high pressure
departing eastward across the Central Plains while lee side
troughing develops across eastern Colorado will return a low level
southerly flow to extreme western Kansas by Friday afternoon.
Slightly warmer air is expected to return to the area raising H85
temperatures well above 0C near the Colorado border while the
colder air mass across central Kansas is slower to erode. Look for
highs up into the 30s(F) across central Kansas Friday afternoon
with highs well up into the 40s(F) in extreme southwest Kansas.
The warming trend will continue into Saturday as a prevailing
southerly flow enhances warm air advection into western Kansas.
Expect highs to reach up into the 40s(F) across central Kansas
Saturday afternoon to the 50s(F) across much of southwest Kansas.
Cooler temperatures return early next week in wake of another cold
front pushing through western Kansas late in the weekend.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z Thursday EVENING)
ISSUED AT 513 PM CST WED JAN 20 2016
A surface boundary will move east across western Kansas early
tonight. As this surface boundary passes the southeast winds at 10
knots or less will shift to the west northwest. These northwest
winds will then increase to near 20 knots between 14z and 17z
Thursday. Although some clearing conditions will develop early
this evening in the DDC area, IFR or low MVFR ceilings and
visibilities will return by 03z based on the latest RAP and HRRR.
These conditions are then expected to continue late Thursday
morning. The steady snow and IFR conditions at HYS will improve
some between 00z and 03z Thursday as the snow tapers off, however
IFR to low MVFR ceilings and visibilities can be expected to
persist through at least 18z Thursday. At GCK VFR conditions are
expected overnight. A period of MVFR conditions will be possible
between 12z and 18z Thursday.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 27 35 19 40 / 10 10 0 0
GCK 27 37 18 45 / 10 10 0 0
EHA 28 40 23 50 / 10 10 0 0
LBL 28 40 24 48 / 10 10 0 0
HYS 25 32 17 35 / 90 40 10 0
P28 28 35 22 37 / 30 20 10 0
&&
.DDC Watches/Warnings/Advisories...
Winter Weather Advisory until 10 PM CST this evening for KSZ031-
046.
&&
$$
SHORT TERM...JJohnson
LONG TERM...JJohnson
AVIATION...Burgert
AREA FORECAST DISCUSSION
NWS GOODLAND KS
251 PM MST TUE JAN 19 2016
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 210 PM MST TUE JAN 19 2016
EARLY AFTERNOON WV IMAGERY AND RAP ANALYSIS SHOWS RIDGING ACROSS THE
ROCKIES WITH A SHORTWAVE TROUGH TRANSITIONING OUT OF THE PLAINS
TOWARDS THE CENTRAL MISSISSIPPI RIVER VALLEY. ANOTHER SHORTWAVE
TROUGH UPSTREAM OF THE RIDGE IS MOVING INTO THE PACIFIC NORTHWEST
WITH A MUCH STRONGER WEST-EAST ORIENTATED UPPER LEVEL JET OVER
NORTHERN CALIFORNIA. AT THE SURFACE LEE TROUGH HAS DEVELOPED OVER
EAST CENTRAL COLORADO (NEAR FRONT RANGE) AND WARM FRONT IS IN THE
PROCESS OF LIFTING OVER THE NORTHEAST PART OF OUR CWA (FROM KMCK TO
KHLC). PERSISTENT STRATUS IS STILL IN PLACE IN OUR EASTERN CWA WITH
CLOUD SHIELD BREAKING UP IN THE WEST.
THIS EVENING-WEDNESDAY MORNING...MAIN CONCERN WILL FOCUS ON POSSIBLE
DENSE FOG DEVELOPMENT THIS EVENING/OVERNIGHT. MODELS SUPPORT LEE
TROUGH SHIFTING EASTWARD WITH SOUTHERLY FLOW QUICKLY DEVELOPING
AFTER SUNSET. THIS SHOULD HELP ADVECT GOOD BL MOISTURE BACK INTO OUR
CWA AND STRATUS IN THE EAST COULD THEN EXPAND WESTWARD. EARLIER
HRRR/RAP SUPPORTED FOG REDEVELOPING AFTER 00Z THIS EVENING NEAR THE
CO/KS BORDER AND SPREADING EASTWARD. LATEST SREF/NAM/RAP/HRRR NOW
SHOWING STRONGER SIGNAL AFTER MIDNIGHT TONIGHT THROUGH EARLY
WEDNESDAY MORNING WITH MAIN FOG AXIS SHIFTED FURTHER EAST (TOWARD
BACK EDGE OF CURRENT STRATUS DECK). I KEPT FOG COVERAGE/TIMING
SIMILAR TO EARLY GUIDANCE COVER POSSIBILITY...HOWEVER CONFIDENCE AT
THIS POINT IS SIGNIFICANTLY LOWER ON WHERE OR IF DENSE FOG MAY
DEVELOP OVER OUR CWA. (FOG MAY BE A GOOD BET BUT DENSE FOG MAY BE
PATCHY).
WEDNESDAY...TWO SHORTWAVES ARE EXPECTED TO MOVE ACROSS THE ROCKIES
AND OVER OUR CWA WITH THE FIRST (WEAKER) SHORTWAVE MOVING OVER OUR
CWA MIDDAY WEDNESDAY. AS WAS INDICATED IN EARLIER GUIDANCE ON MID
SHIFT THERE IS A SIGNIFICANT DRY LAYER FROM ABOVE THE BL TO 600-
700MB. DESPITE FORCING THIS LOWERS CONFIDENCE IN ANY MEASURABLE
PRECIP DURING THE DAY WEDNESDAY. BY LATE WEDNESDAY AFTERNOON THE
SECOND (STRONGER) SHORTWAVE TROUGH DIGS SOUTHEAST AND OVERTAKES THE
FIRST TROUGH WITH A STRONGER UPPER LEVEL JET BEGINNING TO DEVELOP.
BY LATE AFTERNOON THERE IS A WEAK PRECIP SIGNAL IN OUR FAR EASTERN
CWA AND GUIDANCE THERE DOES SHOW SOME MOISTENING OF THE MOISTURE
PROFILE. I KEPT SMALL AREA OF SLIGHT CHANCE POPS IN GRAHAM/NORTON
COUNTIES TO MATCH THIS...BUT CONFIDENCE IS STILL NOT HIGH THAT
THINGS WOULD START THIS EARLY.
OTHER CONCERN FOR WEDNESDAY WILL BE HIGHS. POTENTIAL EXISTS AGAIN
FOR LINGERING STRATUS...HOWEVER WITH TROUGHS MOVING THROUGH THE
REGION THICK/OPAQUE MID-HIGH CLOUD COVER COULD ALSO LIMIT DIURNAL
HEATING. I LOWERED HIGHS IN THE EAST FROM PREVIOUS FORECAST DUE TO
POTENTIAL IMPACTS OF CLOUD COVER. TOUGH CALL AND IF WE WERE TO
CLEAR OUT (MORE LIKELY IN THE WEST) WE COULD SEE HIGHS IN THE
UPPER 40S.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 248 PM MST TUE JAN 19 2016
FORECAST ISSUES WILL BE CHANCE OF PRECIPITATION AND PHASE OF
PRECIPITATION WEDNESDAY NIGHT INTO THURSDAY. SATELLITE SHOWING A
SOMEWHAT AMPLIFIED BUT STILL PROGRESSIVE AND ACTIVE FLOW PATTERN
FROM THE PACIFIC INTO THE WESTERN ATLANTIC. LARGE AND COMPLICATED
UPPER TROUGH IS OVER THE NORTHEAST PACIFIC.
AT JET LEVEL...THE MODELS WERE HAVING A LITTLE TROUBLE WITH THE JET
ALONG THE WEST COAST. AT MID LEVELS...MODELS WERE ALL ABOUT THE SAME
BUT THEY WERE ALSO A LITTLE FAR EAST/FAST WITH THE UPPER TROUGH NOW
COMING ON THE COAST. THE NAM/ECMWF WAS DOING THE BEST ON THE SURFACE
WIND AND PRESSURE FIELD. THE GFS AND CANADIAN WERE DOING THE BEST ON
THE LOW LEVEL THERMAL FIELD WITH MOST MODELS NOT BEING COLD ENOUGH.
WEDNESDAY NIGHT...DEVELOPING PRECIPITATION EVENT IS IN ITS BEGINNING
STAGES. MODELS DIFFERENT ON SPEED...POSITION AND AMPLITUDE OF MID
LEVEL CIRCULATION THAT APPEARS TO BE DEVELOPING ON TOP OF US OR JUST
TO THE EAST OF US. TODAYS MODEL RUNS VERY DIFFERENT THAN 24 HOURS
AGO. BY THE BEGINNING OF THIS PERIOD...MODELS STILL HAVE STRONG
NORTH TO SOUTH JET ON THE WEST SIDE OF THIS UPPER SYSTEM.
THIS COMBINED WITH THE PROBLEM OF THE MODELS INITIALLY HAVING THIS
SYSTEM TOO FAR EAST THIS MORNING...LEADS ME TO BELIEVE THAT WHATEVER
ENDS UP BEING THE SLOWER AND EVEN FURTHER SOUTH SOLUTION WILL END UP
BEING MORE RIGHT. EVEN NOW AM THINKING CURRENT MODEL RUN STILL MAY
BE TOO FAST/FAR NORTH. TROUGH IS ELONGATED AND COMPROMISED OF A
NORTHERN AND SOUTHERN CIRCULATIONS WITHIN THIS TROUGH. PAST
EXPERIENCE HAS SHOWN THIS SETUP IS NOT GREAT FOR A LOT OF
PRECIPITATION.
SAYING ALL THAT...THE FAR EASTERN PORTION OF THE AREA WILL HAVE THE
BEST CHANCE WITH BEST CHANCE OVERALL AT THIS TIME BEING TO THE EAST
OF OUR AREA. THE GRADIENT OF THE CHANCE OF PRECIPITATION WILL BE
REALLY SHARP. PER THE REASONING ABOVE...AM THINKING THAT THE BEST
CHANCE OF PRECIPITATION WILL BE AFTER MIDNIGHT AND THAT IS SUPPORTED
BY THE SREF PROBABILITIES. BEST CHANCE WILL BE VERY LATE IN THE
NIGHT.
THERE IS NOT A LOT OF COLD AIR WITH THIS SYSTEM...AND DEPENDING ON
WHICH MODEL YOU CHOOSE THE CHANGE OVER MAY NOT OCCUR UNTIL LATE
EVENING/AROUND MIDNIGHT WITH THE EASTERN AREAS CHANGING OVER FIRST.
THE PHASE IS REALLY WHERE THERE ARE BIG DIFFERENCES. SOME MODELS
KEEPING TOTALLY DRY OR HAVE JUST ENOUGH MOISTURE IN THE LOW LEVELS
FOR DRIZZLE/FREEZING DRIZZLE. SO A LOT OF UNCERTAINTY WITH THIS
SYSTEM.
THURSDAY/THURSDAY NIGHT...WITH THE PROXIMITY OF THE SYSTEM AND
EXPECTED SLOWNESS...ALONG WITH MID AND UPPER LEVEL LIFT
EXPECTED...EXPECT THE BEST CHANCE OF PRECIPITATION WILL BE IN THE
MORNING AND THEN RAPIDLY DECREASE AND END. IF CURRENT FORECAST PANS
OUT...THE FAR EASTERN PORTION OF THE AREA GETS 1 TO 2 INCHES.
GRADIENT AND DOWNWARD MOTION BEHIND THE SYSTEM WILL CREATE BREEZY TO
WINDY CONDITIONS. THE STRONGEST WINDS ARE AFTER THE SNOW ENDS...AND
WITH TEMPERATURES JUST ABOVE FREEZING...DO NOT EXPECT ANY BLOWING
SNOW PROBLEMS AT THIS TIME. CURRENT HIGH TEMPERATURE FORECAST LOOKS
TO BE IN GOOD SHAPE AND MADE ONLY MINOR ADJUSTMENTS. HOWEVER...IF
MORE SNOW THAN EXPECT IT WILL BE COLDER. LIGHT WINDS AND LITTLE
CLOUD COVER WILL ALLOW OVERNIGHT TEMPERATURES TO DROP A DECENT
AMOUNT.
FRIDAY...STRONG MID/UPPER LEVEL RIDGE BUILDS IN OVER THE AREA.
SURFACE WILL MOVE THROUGH AND TO THE EAST OF THE AREA DURING THE
DAY. SO DO EXPECT RECYCLED COOL AIR. THE EASTERN LOCATIONS WILL BE
THE COLDEST AND OVERALL REDUCED THE HIGH TEMPERATURES A LITTLE.
FRIDAY NIGHT THROUGH TUESDAY...MID AND UPPER RIDGE WILL BE IN PLACE
FROM FRIDAY NIGHT INTO SATURDAY NIGHT SO EXPECT MODERATING
TEMPERATURES AND DRY CONDITIONS. THE INIT WAS REASONABLE WITH THIS
AND MADE NO CHANGES.
A STRONG SHORTWAVE TROUGH...NOT UNLIKE THE ONE THAT WENT THROUGH
THIS MORNING AND SIMILAR ALSO THE SYSTEM EXPECTED WEDNESDAY NIGHT
AND THURSDAY...WILL MOVE THROUGH SUNDAY AND SUNDAY NIGHT. THE INIT
PRODUCED SLIGHT CHANCE POPS DURING THIS PERIOD AND SEEMS REASONABLE.
POSSIBLE THAT THESE CHANCES WILL INCREASE. AFTER THAT RIDGING WILL
MOVE INTO THE AREA AND BRING DRY CONDITIONS AND MODERATING
TEMPERATURES ONCE AGAIN.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1023 AM MST TUE JAN 19 2016
LIGHT SNOW/FLURRIES HAVE TRANSITIONED SOUTHEAST OF BOTH KGLD AND
KMCK TERMINALS WITH IFR CIGS AT KGLD AND MVFR CIGS AT KMCK
LINGERING IN THE EARLY PART OF THE TAF PERIOD. SATELLITE AND
UPSTREAM OBS IN NEBRASKA/COLORADO SUPPORT THIS STRATUS LIFTING
BY THE MIDDLE OF THE AFTERNOON IN LINE WITH SHORT RANGE GUIDANCE.
LEE TROUGH REDEVELOPS THIS EVENING WITH SOUTHERLY RETURN FLOW
BRINGING LOW LEVEL MOISTURE BACK OVER BOTH TERMINALS. THERE IS A
STRONG STRATUS/FOG SIGNAL ON SHORT RANGE GUIDANCE AND ENSEMBLES
AND IT APPEARS LIKELY THAT IFR CIGS/VIS WILL DEVELOP AT KGLD THEN
KMCK LATER. I AM CONCERNED THAT THERE COULD BE A PROLONGED DENSE
FOG EVENT (1/4SM) AT KGLD OR KMCK TONIGHT THROUGH WEDNESDAY
MORNING. CONSENSUS STILL FAVORS PREVAILING VIS AROUND 1SM AT THE
PEAK OF THIS FOG EVENT...SO I WILL HOLD OFF ON LOWER VIS FOR NOW
AS IT MAY END UP BEING MORE OF A TEMPORARY CONDITION IF MODELS
ARE OVERDONE ON COVERAGE AS THEY HAVE BEEN THE LAST FEW DAYS.
CONDITIONS SHOULD CLEAR AS A SERIES OF LARGE SCALE DISTURBANCES
MOVE INTO THE REGION WEDNESDAY MORNING INCREASING LOW LEVEL
MIXING. STRATUS/FOG MAY LINGER LONGER AT KMCK...BUT THE TREND
SHOULD BE TOWARDS IMPROVEMENT MID MORNING WEDNESDAY. THERE IS ALSO
THE POSSIBILITY FOR A FEW SNOW SHOWERS OR FLURRIES BEFORE
18Z...HOWEVER CONFIDENCE IS TOO LOW TO ADD DURING THIS UPDATE.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...BULLER
AVIATION...DR
AREA FORECAST DISCUSSION
NWS GOODLAND KS
211 PM MST TUE JAN 19 2016
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 210 PM MST TUE JAN 19 2016
EARLY AFTERNOON WV IMAGERY AND RAP ANALYSIS SHOWS RIDGING ACROSS THE
ROCKIES WITH A SHORTWAVE TROUGH TRANSITIONING OUT OF THE PLAINS
TOWARDS THE CENTRAL MISSISSIPPI RIVER VALLEY. ANOTHER SHORTWAVE
TROUGH UPSTREAM OF THE RIDGE IS MOVING INTO THE PACIFIC NORTHWEST
WITH A MUCH STRONGER WEST-EAST ORIENTATED UPPER LEVEL JET OVER
NORTHERN CALIFORNIA. AT THE SURFACE LEE TROUGH HAS DEVELOPED OVER
EAST CENTRAL COLORADO (NEAR FRONT RANGE) AND WARM FRONT IS IN THE
PROCESS OF LIFTING OVER THE NORTHEAST PART OF OUR CWA (FROM KMCK TO
KHLC). PERSISTENT STRATUS IS STILL IN PLACE IN OUR EASTERN CWA WITH
CLOUD SHIELD BREAKING UP IN THE WEST.
THIS EVENING-WEDNESDAY MORNING...MAIN CONCERN WILL FOCUS ON POSSIBLE
DENSE FOG DEVELOPMENT THIS EVENING/OVERNIGHT. MODELS SUPPORT LEE
TROUGH SHIFTING EASTWARD WITH SOUTHERLY FLOW QUICKLY DEVELOPING
AFTER SUNSET. THIS SHOULD HELP ADVECT GOOD BL MOISTURE BACK INTO OUR
CWA AND STRATUS IN THE EAST COULD THEN EXPAND WESTWARD. EARLIER
HRRR/RAP SUPPORTED FOG REDEVELOPING AFTER 00Z THIS EVENING NEAR THE
CO/KS BORDER AND SPREADING EASTWARD. LATEST SREF/NAM/RAP/HRRR NOW
SHOWING STRONGER SIGNAL AFTER MIDNIGHT TONIGHT THROUGH EARLY
WEDNESDAY MORNING WITH MAIN FOG AXIS SHIFTED FURTHER EAST (TOWARD
BACK EDGE OF CURRENT STRATUS DECK). I KEPT FOG COVERAGE/TIMING
SIMILAR TO EARLY GUIDANCE COVER POSSIBILITY...HOWEVER CONFIDENCE AT
THIS POINT IS SIGNIFICANTLY LOWER ON WHERE OR IF DENSE FOG MAY
DEVELOP OVER OUR CWA. (FOG MAY BE A GOOD BET BUT DENSE FOG MAY BE
PATCHY).
WEDNESDAY...TWO SHORTWAVES ARE EXPECTED TO MOVE ACROSS THE ROCKIES
AND OVER OUR CWA WITH THE FIRST (WEAKER) SHORTWAVE MOVING OVER OUR
CWA MIDDAY WEDNESDAY. AS WAS INDICATED IN EARLIER GUIDANCE ON MID
SHIFT THERE IS A SIGNIFICANT DRY LAYER FROM ABOVE THE BL TO 600-
700MB. DESPITE FORCING THIS LOWERS CONFIDENCE IN ANY MEASURABLE
PRECIP DURING THE DAY WEDNESDAY. BY LATE WEDNESDAY AFTERNOON THE
SECOND (STRONGER) SHORTWAVE TROUGH DIGS SOUTHEAST AND OVERTAKES THE
FIRST TROUGH WITH A STRONGER UPPER LEVEL JET BEGINNING TO DEVELOP.
BY LATE AFTERNOON THERE IS A WEAK PRECIP SIGNAL IN OUR FAR EASTERN
CWA AND GUIDANCE THERE DOES SHOW SOME MOISTENING OF THE MOISTURE
PROFILE. I KEPT SMALL AREA OF SLIGHT CHANCE POPS IN GRAHAM/NORTON
COUNTIES TO MATCH THIS...BUT CONFIDENCE IS STILL NOT HIGH THAT
THINGS WOULD START THIS EARLY.
OTHER CONCERN FOR WEDNESDAY WILL BE HIGHS. POTENTIAL EXISTS AGAIN
FOR LINGERING STRATUS...HOWEVER WITH TROUGHS MOVING THROUGH THE
REGION THICK/OPAQUE MID-HIGH CLOUD COVER COULD ALSO LIMIT DIURNAL
HEATING. I LOWERED HIGHS IN THE EAST FROM PREVIOUS FORECAST DUE TO
POTENTIAL IMPACTS OF CLOUD COVER. TOUGH CALL AND IF WE WERE TO
CLEAR OUT (MORE LIKELY IN THE WEST) WE COULD SEE HIGHS IN THE
UPPER 40S.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 232 AM MST TUE JAN 19 2016
WEDNESDAY AN UPPER LEVEL SHORT WAVE TROUGH WILL MOVE ACROSS THE TRI-
STATE AREA. THE ENVIRONMENT WILL SATURATE ABOVE 700MB AND THERE
WILL BE WEAK LIFT OVER THE AREA. AM THINKING THIS WILL NOT BE
ENOUGH TO GENERATE PRECIPITATION SO WILL LEAVE THE DAY DRY. HIGHS
WILL BE WARMER THAN YESTERDAY BEFORE THE NEXT COLD FRONT MOVES
THROUGH.
WEDNESDAY NIGHT A SECOND STRONGER SHORT WAVE TROUGH MOVES OVER THE
AREA AND DEEPEN INTO A CLOSED LOW. DESPITE THE LOW CLOSING OFF THE
LIFT WITH IT WILL BE VERY WEAK. THE ENVIRONMENT SATURATES DEEPER
THAN DURING THE DAY BEHIND A COLD FRONT. AM THINKING THE BEST
CHANCE FOR SNOW WILL BE OVER THE NORTHEAST HALF OF THE AREA UNDER
THE CLOSED LOW.
THURSDAY MORNING THERE WILL BE SOME LINGERING LIFT OVER THE
NORTHEAST PART OF THE AREA AS THE CLOSED LOW MOVES EASTWARD.
BEHIND THE CLOSED LOW AN UPPER LEVEL RIDGE WILL BUILD OVER THE AREA.
SNOWFALL TOTALS FROM WEDNESDAY NIGHT THROUGH THURSDAY MORNING WILL
BE AROUND AN INCH OR LESS...WITH THE HIGHER AMOUNTS OVER NORTON AND
GRAHAM COUNTIES. BY THE AFTERNOON WINDS WILL STRENGTHEN AS A STRONG
LOW LEVEL JET MOVES OVERHEAD. GUSTS UP TO 40 ARE LIKELY...WITH THE
STRONGEST WINDS WEST OF HIGHWAY 25.
FRIDAY...A HIGH AMPLITUDE RIDGE AXIS WILL SLOWLY MOVE TOWARD THE
AREA DURING THE DAY IN BETWEEN A DEEP LOW PRESSURE SYSTEM OVER THE
MID ATLANTIC AND APPROACHING UPPER TROUGH ALONG THE WEST COAST. FOR
THE OVERNIGHT HOURS THE RIDGE AXIS MOVES OVER THE AREA. AS HAS BEEN
THE CASE THIS PAST WEEKEND THERE WILL BE TALE OF TWO COMPETING
AIR MASSES. COOLER (AND SLIGHTLY BELOW NORMAL) AIR RESIDES ACROSS
THE FAR EASTERN PORTION OF THE AREA WHERE SOUTHEAST WINDS AROUND A
SFC HIGH RESIDE. TO THE WEST A BIT MILDER TEMPERATURES EXIST WHERE
WINDS ARE FROM THE SOUTHWEST. NO CHANGES TO FORECAST TEMPERATURES
WITH MID 30S TO LOW 40S EAST...UPPER 40S TO AROUND 50 WEST. LOW
TEMPERATURES IN THE LOW TO MID 20S.
WILL HAVE TO WATCH FOR THE POSSIBILITY OF STRATUS AND FREEZING FOG
IN THE MORNING EAST OF THE CO/KS BORDER WHERE BOUNDARY LAYER RH OVER
90%. OTHERWISE SUNNY/MOSTLY SUNNY DURING THE DAY WITH ONLY SOME MID
AND/OR HIGH CLOUDS MOVING IN FROM THE WEST. HIGH CLOUDS MOVE OVER
THE AREA DURING THE NIGHT. NO PRECIPITATION EXPECTED.
SATURDAY...FLOW ALOFT BECOMES ZONAL AS A WEAK TROUGH DEVELOPS ACROSS
THE WEST DURING THE DAY...QUICKLY APPROACHING DURING THE NIGHT. SOME
MID AND HIGH CLOUDS DURING THE DAY...DECREASING DURING THE NIGHT. NO
PRECIPITATION EXPECTED. 850MB TEMPERATURES WARM WHICH IS REFLECTED
IN GUIDANCE AND WILL GO WITH MID 40S TO AROUND 50 EAST...MID TO
POSSIBLY UPPER 50S WEST. LOW TEMPERATURES MILD WITH MID TO UPPER 20S.
SUNDAY...CURRENTLY LOOKING LIKE AFTERNOON TEMPERATURES WILL PEAK
AROUND NOON BEFORE NORTH/NORTHWEST WINDS INCREASE A BIT AS COLD
FRONT MOVES THROUGH. CURRENTLY HAVE HIGHS IN THE LOW 40S TO AROUND
50 (NORTH TO SOUTH) WHICH COULD CHANGE GIVEN FRONTS ARRIVAL.
OTHERWISE LOOKING AT AN INCREASE IN CLOUDS AS SOME UPPER TROUGHING
MOVES OVER THE AREA. CURRENTLY HAVE A SLIGHT CHANCE OF PRECIP ACROSS
THE NORTHEAST CORNER OF THE AREA WHICH IS SOMEWHAT QUESTIONABLE AS
MODELS HAVE DIFFERING SOLUTIONS ON THE SPECIFICS. FOR THE OVERNIGHT
HOURS CURRENTLY HAVE SLIGHTLY ABOVE NORMAL MINS IN THE UPPER TEENS
TO MID 20S UNDER A MOSTLY CLOUDY SKY. WILL HAVE TO ADD A SLIGHT
CHANCE OF LIGHT SNOW TO THE FORECAST WITH THE UPPER TROUGH IN THE
AREA AND FAVORABLE MOISTURE.
MONDAY...CLOUDS LINGER DURING THE DAY WITH A DECREASE DURING THE
NIGHT AS HIGH AMPLITUDE RIDGE AXIS MOVES TOWARD THE INTERMOUNTAIN
WEST. AFTERNOON TEMPERATURES CLOSER TO NORMAL WITH UPPER 30S TO LOW
40S. LOW TEMPERATURES IN THE MID TEENS TO LOW 20S. NO PRECIPITATION
EXPECTED.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1023 AM MST TUE JAN 19 2016
LIGHT SNOW/FLURRIES HAVE TRANSITIONED SOUTHEAST OF BOTH KGLD AND
KMCK TERMINALS WITH IFR CIGS AT KGLD AND MVFR CIGS AT KMCK
LINGERING IN THE EARLY PART OF THE TAF PERIOD. SATELLITE AND
UPSTREAM OBS IN NEBRASKA/COLORADO SUPPORT THIS STRATUS LIFTING
BY THE MIDDLE OF THE AFTERNOON IN LINE WITH SHORT RANGE GUIDANCE.
LEE TROUGH REDEVELOPS THIS EVENING WITH SOUTHERLY RETURN FLOW
BRINGING LOW LEVEL MOISTURE BACK OVER BOTH TERMINALS. THERE IS A
STRONG STRATUS/FOG SIGNAL ON SHORT RANGE GUIDANCE AND ENSEMBLES
AND IT APPEARS LIKELY THAT IFR CIGS/VIS WILL DEVELOP AT KGLD THEN
KMCK LATER. I AM CONCERNED THAT THERE COULD BE A PROLONGED DENSE
FOG EVENT (1/4SM) AT KGLD OR KMCK TONIGHT THROUGH WEDNESDAY
MORNING. CONSENSUS STILL FAVORS PREVAILING VIS AROUND 1SM AT THE
PEAK OF THIS FOG EVENT...SO I WILL HOLD OFF ON LOWER VIS FOR NOW
AS IT MAY END UP BEING MORE OF A TEMPORARY CONDITION IF MODELS
ARE OVERDONE ON COVERAGE AS THEY HAVE BEEN THE LAST FEW DAYS.
CONDITIONS SHOULD CLEAR AS A SERIES OF LARGE SCALE DISTURBANCES
MOVE INTO THE REGION WEDNESDAY MORNING INCREASING LOW LEVEL
MIXING. STRATUS/FOG MAY LINGER LONGER AT KMCK...BUT THE TREND
SHOULD BE TOWARDS IMPROVEMENT MID MORNING WEDNESDAY. THERE IS ALSO
THE POSSIBILITY FOR A FEW SNOW SHOWERS OR FLURRIES BEFORE
18Z...HOWEVER CONFIDENCE IS TOO LOW TO ADD DURING THIS UPDATE.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...99/JTL
AVIATION...DR
AREA FORECAST DISCUSSION
NWS WICHITA KS
1138 AM CST TUE JAN 19 2016
...UPDATED FOR 18Z AVIATION DISCUSSION...
.UPDATE...
ISSUED AT 1028 AM CST TUE JAN 19 2016
MAY NEED TO CONSIDER EXPANDING THE WINTER WEATHER ADVISORY
FURTHER WEST TO GENERALLY I-135 THIS AFTERNOON/EVENING...INCLUDING
THE WICHITA METRO. LATEST RAP AND OTHER SHORT-TERM GUIDANCE
SUGGESTS POTENTIAL FOR FREEZING DRIZZLE AS FAR WEST AS HUTCHINSON-
SALINA...DEVELOPING LATE THIS MORNING BUT ESPECIALLY THIS
AFTERNOON-EVENING. GREATEST POTENTIAL STILL LOOKS TO BE GENERALLY
FLINT HILLS ON EAST. ANTICIPATING SNOW ACCUMULATIONS TO BE
MINIMAL...GENERALLY ONE-HALF INCH OR LESS NORTH OF I-70...AND ALSO
OVER SOUTHEAST KANSAS. WILL CONTINUE TO MONITOR TRENDS AND MAKE
TIMELY UPDATES.
ADK
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 359 AM CST TUE JAN 19 2016
A FAST MOVING STORM SYSTEM OVER THE ROCKIES WILL MOVE QUICKLY
EAST ACROSS THE CENTRAL PLAINS STATES TODAY. A PERIOD OF LIGHT
MIXED PRECIPITATION IS ANTICIPATED THROUGH EARLY EVENING BUT
ACCUMULATIONS ARE EXPECTED TO REMAIN LIGHT GIVEN THE PROGRESSIVE
NATURE OF THE MID/UPPER TROUGH AND LACK OF COUPLED FORCING/SCARCE
MOISTURE AVAILABILITY. TEMPERATURES MAY EVEN RISE ABOVE FREEZING
ACROSS FAR SOUTHERN KANSAS RESULTING IN DRIZZLE OR LIGHT RAIN
DURING THE AFTERNOON HOURS. FINALLY...PRECIPITATION IS EXPECTED TO
CHANGE TO PREDOMINATELY SNOW OVER SOUTHEAST KS BY LATE
AFTERNOON/EARLY EVENING WHERE UP TO AN INCH WILL BE POSSIBLE
BEFORE THE ACTIVITY MOVES EAST BY 03-05Z. THE CURRENT WINTER
WEATHER ADVISORY APPEARS TO CAPTURE THE AREA WELL WITH NO CHANGES
PLANNED AT THIS TIME.
WED-THU...SHORTWAVE RIDGING WILL BUILD ACROSS THE CENTRAL PLAINS
STATES ON WED AHEAD OF ANOTHER SHORTWAVE TROUGH MOVING INTO THE
ROCKIES LATE IN THE DAY. LOW LEVEL SOUTHERLY FLOW WILL HELP BOOST
TEMPERATURES INTO THE MID AND UPPER 30S. LARGE-SCALE FORCING FOR
ASCENT WILL INCREASE LATE IN THE DAY WITH SCT RAIN/SNOW SHOWERS
POSSIBLE AFTER 21Z. BETTER CHANCES FOR LIGHT SNOW ACCUMULATIONS
WILL ARRIVE WED NIGHT AND CONTINUE INTO THURSDAY AS A MID/UPPER
TROUGH DEEPENS OVER THE CENTRAL PLAINS STATES. A GENERAL 1-3
INCHES APPEARS POSSIBLE ACROSS MUCH OF THE AREA BEFORE
PRECIPITATION DIMINISHES FROM WEST TO EAST THURSDAY EVENING.
.LONG TERM...(FRIDAY THROUGH MONDAY)
ISSUED AT 359 AM CST TUE JAN 19 2016
A MID/UPPER RIDGE WILL ARRIVE TOWARD THE END OF THE WEEK AND
BEGINNING OF THE WEEKEND BRINGING RISING HEIGHTS/INCREASING
THICKNESS AND RISING TEMPERATURES TO THE CENTRAL PLAINS STATES.
HIGHS MAY REACH 50 ACROSS THE AREA ON SAT/SUN BEFORE ANOTHER
PROGRESSIVE SHORTWAVE TROUGH ARRIVES TOWARD THE END OF THE PERIOD
SENDING A SURGE OF CANADIAN AIR SOUTH ACROSS THE AREA AS WE MOVE
INTO THE NEW WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1138 AM CST TUE JAN 19 2016
ANTICIPATING PATCHY TO AREAS OF FREEZING DRIZZLE TO DEVELOP EARLY
THIS AFTERNOON AND PERSIST THROUGH LATE AFTERNOON AND EVENING
GENERALLY ALONG/EAST OF I-135. ALREADY STARTING TO SEE SIGNS OF
THIS IN THE OBSERVATIONAL DATA...AS WELL AS A HANDFUL OF GROUND
TRUTH REPORTS. TERMINALS IMPACTED WILL BE WICHITA AND
CHANUTE...AND POSSIBLY HUTCHINSON AND SALINA AS WELL. COULD SEE A
THIN GLAZE OF ICE ACCUMULATION. FURTHER NORTHWEST...A NARROW BAND
OF LIGHT SNOW MAY AFFECT RUSSELL...GREAT BEND AND SALINA THIS
AFTERNOON...AHEAD OF THE MAIN UPPER SYSTEM PUSHING THROUGH. SNOW
ACCUMULATIONS WILL BE MINIMAL. MVFR TO IFR CIGS WILL PREVAIL
THROUGH AT LEAST THE EVENING...POSSIBLY LONGER.
ADK
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 32 18 37 28 / 40 20 10 60
HUTCHINSON 30 17 36 27 / 30 10 20 60
NEWTON 30 17 36 28 / 40 20 10 60
ELDORADO 31 19 36 30 / 50 20 10 60
WINFIELD-KWLD 34 20 38 29 / 40 20 10 50
RUSSELL 31 18 40 28 / 20 10 20 50
GREAT BEND 31 18 39 28 / 20 10 20 50
SALINA 29 19 38 27 / 30 10 10 50
MCPHERSON 30 18 36 27 / 30 10 20 60
COFFEYVILLE 35 22 38 31 / 60 40 10 30
CHANUTE 32 20 36 29 / 70 50 10 40
IOLA 31 19 35 29 / 70 60 10 30
PARSONS-KPPF 34 21 36 30 / 70 40 10 40
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 9 PM CST THIS EVENING FOR KSZ071-
072-096.
&&
$$
AREA FORECAST DISCUSSION
NWS WICHITA KS
1031 AM CST TUE JAN 19 2016
.UPDATE...
ISSUED AT 1028 AM CST TUE JAN 19 2016
MAY NEED TO CONSIDER EXPANDING THE WINTER WEATHER ADVISORY FURTHER
WEST TO GENERALLY I-135 THIS AFTERNOON/EVENING...INCLUDING THE
WICHITA METRO. LATEST RAP AND OTHER SHORT-TERM GUIDANCE SUGGESTS
POTENTIAL FOR FREEZING DRIZZLE AS FAR WEST AS HUTCHINSON-
SALINA...DEVELOPING LATE THIS MORNING BUT ESPECIALLY THIS
AFTERNOON-EVENING. GREATEST POTENTIAL STILL LOOKS TO BE GENERALLY
FLINT HILLS ON EAST. ANTICIPATING SNOW ACCUMULATIONS TO BE
MINIMAL...GENERALLY ONE-HALF INCH OR LESS NORTH OF I-70...AND
ALSO OVER SOUTHEAST KANSAS. WILL CONTINUE TO MONITOR TRENDS AND
MAKE TIMELY UPDATES.
ADK
&&
UPDATE ISSUED AT 606 AM CST TUE JAN 19 2016
UPDATED TO PUSH BACK THE ONSET OF ANY WINTRY PRECIP.
LOW LEVEL DRY ADVECTION WILL CONTINUE THIS MORNING WHICH WILL KEEP
THE LOW LAYERS TOO DRY FOR ANY FREEZING DRIZZLE...AT LEAST FOR
MOST OF THE MORNING. SOME LIGHT SNOW AND OR PATCHY FREEZING
DRIZZLE STILL LOOKS POSSIBLE THIS AFTERNOON.
LAWSON
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 359 AM CST TUE JAN 19 2016
A FAST MOVING STORM SYSTEM OVER THE ROCKIES WILL MOVE QUICKLY EAST
ACROSS THE CENTRAL PLAINS STATES TODAY. A PERIOD OF LIGHT MIXED
PRECIPITATION IS ANTICIPATED THROUGH EARLY EVENING BUT ACCUMULATIONS
ARE EXPECTED TO REMAIN LIGHT GIVEN THE PROGRESSIVE NATURE OF THE
MID/UPPER TROUGH AND LACK OF COUPLED FORCING/SCARCE MOISTURE
AVAILABILITY. TEMPERATURES MAY EVEN RISE ABOVE FREEZING ACROSS FAR
SOUTHERN KANSAS RESULTING IN DRIZZLE OR LIGHT RAIN DURING THE
AFTERNOON HOURS. FINALLY...PRECIPITATION IS EXPECTED TO CHANGE TO
PREDOMINATELY SNOW OVER SOUTHEAST KS BY LATE AFTERNOON/EARLY EVENING
WHERE UP TO AN INCH WILL BE POSSIBLE BEFORE THE ACTIVITY MOVES EAST
BY 03-05Z. THE CURRENT WINTER WEATHER ADVISORY APPEARS TO CAPTURE THE
AREA WELL WITH NO CHANGES PLANNED AT THIS TIME.
WED-THU...SHORTWAVE RIDGING WILL BUILD ACROSS THE CENTRAL PLAINS
STATES ON WED AHEAD OF ANOTHER SHORTWAVE TROUGH MOVING INTO THE
ROCKIES LATE IN THE DAY. LOW LEVEL SOUTHERLY FLOW WILL HELP BOOST
TEMPERATURES INTO THE MID AND UPPER 30S. LARGE-SCALE FORCING FOR
ASCENT WILL INCREASE LATE IN THE DAY WITH SCT RAIN/SNOW SHOWERS
POSSIBLE AFTER 21Z. BETTER CHANCES FOR LIGHT SNOW ACCUMULATIONS WILL
ARRIVE WED NIGHT AND CONTINUE INTO THURSDAY AS A MID/UPPER TROUGH
DEEPENS OVER THE CENTRAL PLAINS STATES. A GENERAL 1-3 INCHES APPEARS
POSSIBLE ACROSS MUCH OF THE AREA BEFORE PRECIPITATION DIMINISHES
FROM WEST TO EAST THURSDAY EVENING.
.LONG TERM...(FRIDAY THROUGH MONDAY)
ISSUED AT 359 AM CST TUE JAN 19 2016
A MID/UPPER RIDGE WILL ARRIVE TOWARD THE END OF THE WEEK
AND BEGINNING OF THE WEEKEND BRINGING RISING HEIGHTS/INCREASING
THICKNESS AND RISING TEMPERATURES TO THE CENTRAL PLAINS STATES.
HIGHS MAY REACH 50 ACROSS THE AREA ON SAT/SUN BEFORE ANOTHER
PROGRESSIVE SHORTWAVE TROUGH ARRIVES TOWARD THE END OF THE PERIOD
SENDING A SURGE OF CANADIAN AIR SOUTH ACROSS THE AREA AS WE MOVE
INTO THE NEW WEEK.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 542 AM CST TUE JAN 19 2016
AVIATION CONCERNS WILL BE LOWER CIGS TODAY ALONG WITH A CHANCE FOR
SOME WINTRY PRECIP.
WATER VAPOR IMAGERY SHOWS SHORTWAVE ENERGY READY TO MOVE OUT
ACROSS THE SOUTHERN HIGH PLAINS. ISENTROPIC LIFT/WARM ADVECTION
OUT AHEAD OF THIS WAVE HAS RESULTED IN LIGHT SNOW OVER CENTRAL
NEBRASKA. LOW CLOUDS CURRENTLY STRETCH NEAR AND ESPECIALLY NORTH
OF I-70 AND SHOULD STAY IN THIS LOCATION FOR THE NEXT COUPLE OF
HOURS. AFTER THIS TIME THEY SHOULD START TO PUSH SOUTH
ENCOMPASSING MOST TAF SITES. AT THIS POINT WILL JUST RUN WITH
MVFR LEVELS WITH IFR THIS AFTERNOON AT KCNU.
EAST WINDS ACROSS THE ENTIRE AREA HAS BEEN PROVIDING LOW LEVEL DRY
ADVECTION WHICH HAS LIMITED ANY LOW LEVEL SATURATION AND
ASSOCIATED FREEZING DRIZZLE. THEREFORE HAVE DELAYED THE START OF
ANY WINTRY PRECIP BY A FEW HOURS AND DON`T THINK WE`LL SEE MUCH
BEFORE 16Z. FEEL THE LOW LEVEL DRY ADVECTION WILL LIMIT ANY
SIGNIFICANT ICE OR SNOW WITH SE KS HAVING THE BEST CHANCE TO SEE
MEASURABLE SNOW THIS AFTERNOON.
LAWSON
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 32 18 37 28 / 40 20 10 60
HUTCHINSON 30 17 36 27 / 30 10 20 60
NEWTON 30 17 36 28 / 40 20 10 60
ELDORADO 31 19 36 30 / 50 20 10 60
WINFIELD-KWLD 34 20 38 29 / 40 20 10 50
RUSSELL 31 18 40 28 / 20 10 20 50
GREAT BEND 31 18 39 28 / 20 10 20 50
SALINA 29 19 38 27 / 30 10 10 50
MCPHERSON 30 18 36 27 / 30 10 20 60
COFFEYVILLE 35 22 38 31 / 60 40 10 30
CHANUTE 32 20 36 29 / 70 50 10 40
IOLA 31 19 35 29 / 70 60 10 30
PARSONS-KPPF 34 21 36 30 / 70 40 10 40
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 9 PM CST THIS EVENING FOR KSZ071-
072-096.
&&
$$
AREA FORECAST DISCUSSION
National Weather Service Topeka KS
347 AM CST TUE JAN 19 2016
.SHORT TERM...(Today and Tonight)
Issued at 346 AM CST TUE JAN 19 2016
An upper level trough extended from the northern plains, south-
southwest across the central high plains into northeast NM early
this morning. The upper level trough will amplify slightly as it
moves east across the central and southern plains. Light
reflectivity returns on radar during the morning hours across the
northern and western CWA have not resulted in any light snow at this
time but through the morning hours the mid and low-levels of the
atmosphere should begin to saturate for light snow to develop along
the NE border with possible flurries farther south after 12Z. The
stronger ascent and mid level frontogenesis will not develop across
the eastern half of the CWA until the afternoon hours, then the snow
tempo should pick up enough for 1 to 2 inches of snow, generally
along and east of a Marysville to Burlington line. West of this line
expect only a dusting of snow in our southwest counties with half an
inch to 1 inch across north central KS.
vertical cross sections, perpendicular to the H5 thermal axis from
several model runs, show a stronger band of frontogenesis at 700mb
and some CSI across east central KS late this afternoon. Early in
the afternoon weak isentropic lift may saturate the low-levels
enough for patchy freezing drizzle to develop, before the stronger
lift shifts eastward for steadier light snow to develop. The 00Z NAM
forecast soundings never show much saturation within the dendritic
growth zone across the southwest counties, thus accumulations of
snow may only be dusting due to flurries but there may be a period
of freezing drizzle this afternoon across the southwest and southern
counties of the CWA. Any ice accumulations due to freezing drizzle
will remain light, less than one hundredths of an inch but could
produce a light glaze on area roadways.
The latest WRF runs (ARW and NMM) forecast more moderate snow bands
developing along the southeast counties of the CWA during the late
afternoon hours, where 1 to 2 inches of snowfall may occur. Even the
NAM models shows a more intense PV anomaly moving east across
southeast and east central KS, which could provide more lift in the
mid and upper levels of the atmosphere across the southeast counties
of the CWA. The next shift may have to adjust snow accumulations
slightly if the WRF solutions verify.
I will continue with the winter weather advisory for the eastern
half of the CWA. I added Marshall county into the advisory since
they could see over an inch of snowfall.
The clouds cover and light snowfall this afternoon should keep high
temperatures in mid to upper 20s.
The upper trough will shift east into MO after 00Z and the snow
should end across east central and northeast KS during the the early
evening hours. There may be a brief period of patchy freezing
drizzle across east central KS this evening before isentropic down
glide dries out the the low-levels of the atmosphere. Late Tonight
skies may begin to clear. In areas with snow cover and clear skies,
temperatures may drop into the upper single digits. If the clouds
hold through the night, then lows will only did down into the mid
teens.
.LONG TERM...(Wednesday through Monday)
Issued at 346 AM CST TUE JAN 19 2016
The most interesting time frame in the mid-term range forecast
remains from late Wednesday night through the day on Thursday. The
synoptic setup will be that a lead minor shortwave will act as a
source of lift and begin to develop areas of light snow late
Wednesday into Thursday early morning. After midnight into the
daybreak time frame, the main trough will pull out of the Central
Rockies and deepen into a closed upper low allowing for increased
ascent and further saturation of the underlying airmass. GFS
Ensembles are not yet in huge agreement on the precip amount, but do
at least tend to focus generally over the same region as the SREF
probabilities. Therefore, have increased POPs mainly southwest of a
line from Marysville through Topeka into Ottawa areas. Not
expecting huge snow accumulations, but it does appear more likely
that a good measurable snow will occur during the morning into the
afternoon on Thursday. While the GFS is the deeper and therefore
stronger of the solutions, the ECMWF and NAM solutions do agree
well overall with timing and location of precip amounts.
Additionally, all solutions keep a colder airmass in place with 540
thickness line off over southern KS. This all leads to increasing
confidence in the idea that snow will be the dominate precipitation
type over East Central Kansas into northeastern KS. This system
will move out of the area with the passage of the upper trough early
Friday and as it continues to deepen a strong ridge will build over
the Central and Northern Plains on Friday into the weekend. For the
rest of the period a fairly zonal pattern eventually takes shape
with temperatures holding near normal for this time of year with
only a very small chance of snow reaching the Nebraska/Kansas border
by Monday morning. Chances still too small at this point to enter
as slight POPs, so have not included any snow mention this forecast
period as this is the point where guidance begins to diverge from
one solution to the next by a fairly wide amount.
&&
.AVIATION...(For the 06Z TAFS through 06Z Tuesday Night)
Issued at 1134 PM CST MON JAN 18 2016
VFR conditions expected to become mvfr cigs in 09Z-12Z time
period. SN to develop in the 16Z-19Z time period with mvfr vsbys
transitioning to ifr cigs and vsbys by 19Z. VSBYS are expected to
improve to vfr after 00Z in MHK and around 03Z at TOP and FOE.
Latest soundings from RAP and NAM show precip type to be all snow.
Winds southeast to east around 10 kts, becoming northeast under 10
kts after 00Z.
&&
.TOP Watches/Warnings/Advisories...
Winter Weather Advisory from 9 AM this morning to 9 PM CST this
evening for KSZ023-024-026-038>040-054>056-058-059.
Winter Weather Advisory until 9 PM CST this evening for
KSZ010>012.
&&
$$
SHORT TERM...Gargan
LONG TERM...Drake
AVIATION...53
AREA FORECAST DISCUSSION
National Weather Service Topeka KS
1134 PM CST MON JAN 18 2016
...Update to aviation forecast discussion...
.SHORT TERM...(This Evening through Tuesday)
Issued at 311 PM CST MON JAN 18 2016
The main focus for the short-term is on the potential for snow
and freezing drizzle across the outlook area Tuesday and Tuesday
night.
Surface high pressure was centered over Missouri today, resulting in
southerly winds and gradual scattering of low/mid clouds which
helped to boost afternoon temperatures into the 20s to around 30
degrees for much of the CWA. The only exception was across Brown Co
where the deeper snowpack kept temperatures in the upper teens/near
20 degrees. Water vapor imagery showed a few embedded waves within
the mid-level flow across Montana and Wyoming this afternoon. Models
show these waves deepening as they track southeastward into the
central U.S. on Tuesday, exiting the area Tuesday night. Have kept a
dry forecast for tonight, but the increasing low/mid clouds along
with light southeasterly winds will limit radiational cooling
tonight, keeping low temperatures in the teens/low 20s. In fact,
these low temperatures will likely occur this evening with
temperatures gradually rising during the overnight hours, so have
gone with a non-diurnal temperature trend for tonight. Models show
the moisture and lift initially skimming across/near the
Kansas/Nebraska border Tuesday morning. However, model soundings
show shallow moisture with lift in the low-levels across much of the
CWA by mid to late morning. Soundings struggle to show deep enough
saturation extending into the dendritic growth zone during the
morning hours for much of the southern half of the CWA (but
especially across east central Kansas), so there is an increasing
concern for freezing drizzle generally along and south of I-70 and
more-so along and south of I-35. Near the I-70 corridor, model
soundings start showing some saturation in the dendritic growth zone
during the afternoon hours with a diminishing dry layer and cool
enough temperatures to likely support a transition over to snow by
mid to late afternoon. However, soundings struggle to bring
saturation into the dendritic zone for locations generally along and
south of I-35, so precipitation may predominantly be in the form of
freezing drizzle throughout the day. Temperatures should be cool
enough by Tuesday evening to have any lingering precipitation across
far northeast and far east central Kansas in the form of snow, with
the system exiting the area by mid to late evening.
There are some model discrepancies with regards to QPF amounts, with
the NAM showing the least amount. These discrepancies result in some
uncertainties with the exact snow and ice accumulations. The best
QPF will be focused across far northeast Kansas and this
precipitation should remain in the form of snow, resulting in 1 to 3
inches of snow accumulation. Expect this snow accumulation to be
primarily from mid morning through the afternoon hours. The lightest
snow accumulations should generally be along and west of a line from
Washington to Manhattan to Garnett with anywhere from a dusting to
upwards of around 1 inch. As for ice accumulations, cannot rule out
a light glaze of ice as far north as around the I-70 corridor
(during the morning hours), with a few hundredths of an inch of ice
accumulation possible along and south of I-35 (with these
accumulations occurring through the afternoon hours). As a result,
some snow-packed roads will be possible across northeast and
portions of east central Kansas, with slick road conditions from
light ice accumulations possible across east central Kansas. With
these accumulation amounts and impacts in mind, have issued a Winter
Weather Advisory for portions of northeast and east central Kansas.
Temperatures will remain cool on Tuesday with highs only in the 20s
to around 30 with lows Tuesday night dropping into the teens/around
20 degrees.
.LONG TERM...(Tuesday Night through Monday)
Issued at 311 PM CST MON JAN 18 2016
Still considerable differences in how models handle incoming
shortwave trofs for late Wednesday into Thursday. NAM brings a
few inches of snow to the western counties with the leading wave
before sunrise, while the GFS develops light accumulations over
the east and takes better piece of energy off to the south. EC
brings leading system out stronger and faster from the Rockies
before dropping the trof across central KS, also producing some
low end snow accumulations out west, with northerly shortwave wave
possibly extending some light snow into Thursday evening. NAM
soundings suggest snow growth zone could remain dry in the western
counties and bring freezing drizzle as opposed to snow. Too much
variability for much confidence in details. Will carry slight
chance to chance for precip, with mix possible in the western
counties.
Highs Wednesday slightly above freezing drop to freezing or below
for highs on Thursday, while upper 20s to low 30s come in behind
the system for Friday. Weekend brings a warming trend back toward
the 40s before next potential system may bring in cooler air for
Monday.
&&
.AVIATION...(For the 06Z TAFS through 06Z Tuesday Night)
Issued at 1134 PM CST MON JAN 18 2016
VFR conditions expected to become mvfr cigs in 09Z-12Z time
period. SN to develop in the 16Z-19Z time period with mvfr vsbys
transitioning to ifr cigs and vsbys by 19Z. VSBYS are expected to
improve to vfr after 00Z in MHK and around 03Z at TOP and FOE.
Latest soundings from RAP and NAM show precip type to be all snow.
Winds southeast to east around 10 kts, becoming northeast under 10
kts after 00Z.
&&
.TOP Watches/Warnings/Advisories...
Winter Weather Advisory from 9 AM Tuesday to midnight CST
Tuesday night for KSZ023-024-026-038>040-054>056-058-059.
Winter Weather Advisory from 6 AM Tuesday to midnight CST
Tuesday night for KSZ011-012.
&&
$$
SHORT TERM...Hennecke
LONG TERM...67
AVIATION...53
AREA FORECAST DISCUSSION...UPDATED
NWS SHREVEPORT LA
1001 PM CST WED JAN 20 2016
.DISCUSSION...
PRECIP HAS YET TO DEVELOP ACROSS THE AREA AS THE UPPER LVL FORCING
IS JUST NOW REACHING THE AREA. LATEST HRRR AND 00Z NAM BOTH
INDICATE DEVELOPMENT SHOULD OCCUR AROUND OR JUST AFTER MIDNIGHT. A
FEW MINOR ADJUSTMENTS WERE MADE TO THE POP/QPF/WX GRIDS THROUGH
12Z FRIDAY. A WARM FRONT IS CURRENTLY LIFTING NEWD THROUGH E TX SO
PORTIONS OF THE AREA ARE STILL EXPERIENCING COLD AIR ADVECTION
AND ARE ALREADY APPROACHING FCST LOW TEMPS FOR TONIGHT. WARM FRONT
IS EXPECTED TO STALL CLOSE TO THE I-20 CORRIDOR. HAVE LOWERED THE
MIN TEMPS FCST FOR TONIGHT IN MOST AREAS NORTH OF I-20 WHERE THE
CAA WILL PERSIST.
UPDATED TEXT PRODUCTS WILL BE SENT SHORTLY. /09/
&&
.PREV DISCUSSION... /ISSUED 548 PM CST WED JAN 20 2016/
AVIATION...
CONDITIONS TO DETERIORATE TO IFR/LIFR OVERNIGHT AS A WARM FRONT
LIFTS NORTH ACROSS THE ARKLATEX BRINGING A CHANCE OF SHOWERS AND
ISOLATED THUNDERSTORMS AFTER 21/06Z. A SURFACE LOW ACROSS TEXAS
WILL MOVE ACROSS THE REGION ON THURSDAY MAINTAINING IFR/LIFR
CONDITIONS ALONG WITH SHOWERS AND EMBEDDED THUNDERSTORMS.
OTHERWISE...EAST WINDS THIS EVENING AROUND 5 KNOTS TO BECOME
SOUTHEAST AFTER 21/06Z. WINDS TO BECOME SOUTHWEST AT 10 KNOTS WITH
HIGHER GUSTS ACROSS EAST TEXAS TERMINAL SITES AFTER 21/18Z. /05/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 43 57 37 46 / 40 70 50 10
MLU 38 57 39 45 / 40 80 60 20
DEQ 35 44 31 44 / 40 70 40 10
TXK 36 46 34 44 / 40 70 50 10
ELD 35 46 35 44 / 40 80 60 20
TYR 46 54 35 46 / 40 50 20 10
GGG 43 56 35 46 / 40 50 40 10
LFK 53 65 38 48 / 40 60 20 10
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
LA...NONE.
OK...NONE.
TX...NONE.
&&
$$
09
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
558 PM EST TUE JAN 19 2016
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 354 PM EST TUE JAN 19 2016
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW SHRTWV RDG
STRETCHING FM NW ONTARIO IN MN WITHIN NW FLOW ALF ON WRN FLANK OF
DEPARTING UPR LO OVER SE CANADA. ASSOCIATED SFC HI PRES RDG
STRETCHES FM NW ONTARIO THRU THE UPR MS RIVER VALLEY AND TOWARD THE
OH RIVER VALLEY. NW FLOW OF COLD AIR...WITH H925 TEMPS ARND -15C
OVER THE UPR LKS...IN ADVANCE OF THIS SLOWLY APRCHG RDG IS STILL
CAUSING SOME LES...BUT BANDS ARE WEAKER/MORE DISORGANIZED WITH
STRONG SUBSIDENCE ASSOCIATED WITH THE APRCHG RDG LOWERING INVRN BASE
TOWARD 3-4K FT AGL PER MQT VWP. LLVL WINDS ARE BEGINNING TO BACK AS
WELL AHEAD OF THE APRCHG SFC RDG...SO BANDS ARE SHIFTING/LIMITING
RESIDENCE TIME. PLENTY OF LO CLDS LINGER UNDER THE LOWERING INVRN
DESPITE DRY NATURE OF THE NEAR SFC LYR UPSTREAM /WHERE SFC DEWPTS
ARE AOB -20F OVER MUCH OF NRN MN...BUT SOME BREAKS ARE BEGINNING TO
SHOW UP OVER THE FAR W NEAR IWD CLOSER TO THE INCOMING SFC HI PRES/
DRY LLVL AIR AND OVER THE SCENTRL WHERE NW FLOW IS DOWNSLOPING.
THERE IS ANOTHER SHRTWV STRETCHING FM SASKATCHEWAN INTO THE NRN
PLAINS THAT IS DIGGING SEWD...AND SOME HI/MID CLDS AHEAD OF THIS
DISTURBANCE ARE SPREADING INTO MN.
MAIN FCST CONCERNS IN THE SHORT TERM FOCUS ON LINGERING LES TRENDS/
LO CLDS AND IMPACT ON TEMPS.
TNGT...SFC HI PRES RDG AXIS IS FCST TO SHIFT SLOWLY TO THE E AND
STRETCH FM THE UPR OH VALLEY INTO UPR MI AT 12Z WED. AS THE LLVL
WINDS CONTINUE TO BACK TOWARD THE WSW...ANY LINGERING SN SHOWERS
OVER THE NRN KEWEENAW AND NEAR LK SUP E OF GRAND MARAIS SHOULD LIFT
OUT INTO LK SUP. SINCE THE WINDS WL SHIFT OFFSHORE AND THE INVRN
BASE WL LOWER WITH MORE ACYC LLVL FLOW...EXPECT THE BULK OF THE LO
CLDS TO SHIFT OVER THE LK AS WELL. ALTHOUGH THE SETUP SEEMS
FAVORABLE FOR VERY LO TEMPS WITH LGT OFFSHORE WINDS...MID/HI CLDS ON
THE NRN FRINGES OF SHRTWV DIGGING TO THE SE ARE FCST TO MOVE OVER
THE CWA AND LIMIT THE DIURNAL TEMP FALL. SO ALTHOUGH THERE MAY BE
SOME SUB ZERO MIN TEMPS OVER THE INTERIOR...WIDESPREAD MIN TEMPS
UNDER -10F AS OBSVD THIS MRNG OVER NRN MN ARE NOT LIKELY.
WED...LARGE SCALE QVECTOR DVGC AHEAD OF SHRTWV RDG AND UNDER SFC RDG
AXIS WL MAINTAIN MAINLY DRY WX FOR MOST OF THE CWA...WITH ANY SN
SHOWERS OVER LK SUP NEAR LK INDUCED TROF FCST TO LINGER OVER THE N
HALF OF THE LK. DURING THE DAY...MANY OF THE MODELS SHOW SOME MSTR
RETURN OVER MAINLY THE WRN CWA IN THE SW FLOW BTWN THE SFC RDG
SHIFTING SLOWLY TO THE E AND A SHRTWV APRCHG LATE IN THE DAY FM THE
NW. BUT SINCE ANY FORCING AND LLVL MSTR INFLOW WL BE MINIMAL...OPTED
TO RETAIN ONLY SCHC POPS OVER THE WRN CWA WHERE THE MOISTENING IS
FCST TO BE A BIT MORE ROBUST. EXPECT A SOMEWHAT WARMER AFTN WITH H85
TEMPS REBOUNDING TO ARND -12C BY 00Z THU.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 446 PM EST TUE JAN 19 2016
BY 00Z THURSDAY THE SFC HIGH WILL HAVE SLIPPED TO IL-OH...WITH A
WEAK RIDGE/LAKE INDUCED LOW SLOWLY DEEPENING ACROSS LAKE SUPERIOR AS
THE RIDGE EXITS. THE NEXT IN A SERIES OF SHORTWAVES WILL ASSIST IN
THE LIGHT SNOW SHOWER POTENTIAL WEDNESDAY NIGHT...TRACKING FROM SW
ONTARIO AT 00Z TO FAR N LAKE HURON BY DAYBREAK THURSDAY. THE MAIN
IMPACT WILL BE TO INCREASE NW FLOW ACROSS THE KEWEENAW PENINSULA
BEHIND THE WEAK SFC-500MB TROUGH AND ENHANCING LIGHT SNOW SHOWERS
THERE. 850MB TEMPS WILL BE AROUND -11C. NOT EXPECTING ADVISORY
SNOW AMOUNTS AT THIS TIME.
THE NEXT SFC HIGH SITUATED OVER MANITOBA AND N DAKOTA THURSDAY WILL
PUSH ACROSS MN AND W LAKE SUPERIOR ON FRIDAY...BUT WILL ONLY SLOWLY
BREAK DOWN THE LINGERING WEAK TROUGH OVER E LAKE SUPERIOR/E UPPER MI
BY FRIDAY NIGHT. SFC WINDS WILL SHIFT OUT OF THE N THURSDAY NIGHT
THROUGH FRIDAY AND 850MB TEMPS WILL FALL TO -12 TO -14C...BUT WITH
LIMITED MOISTURE...EXPECT SNOWFALL LESS THAN 2IN.
ANOTHER DRY PERIOD IS EXPECTED FRIDAY NIGHT THROUGH SATURDAY NIGHT
AS ANOTHER AREA OF HIGH PRESSURE SHIFTS ACROSS THE REGION. BY
SATURDAY MORNING ...THE NEXT LOW WILL BET SET UP ACROSS S CENTRAL
CANADA WHILE MUCH OF THE ATTENTION WILL BE ON THE TRACK AND TIMING
OF THE LOW OFF THE MID ATLANTIC COAST. UPPER MI WILL REMAIN IN
BETWEEN SYSTEMS UNTIL THE CANADIAN LOW SHIFTS ACROSS ONTARIO SUNDAY
AND THE EASTERN LOW MOVES OFF THE NEW ENGLAND STATES. THE TROUGH
LOOKS TO CROSS UPPER MI LATE SUNDAY NIGHT/MONDAY MORNING. THE GFS
AND ECMWF ARE OVER 12HRS ON TIMING WHEN THE NEXT SWATH OF SNOW WILL
CROSS UPPER MI SUNDAY AFTERNOON-MONDAY...WITH DIFFERENCES IN THE
TIMING OF THE NEXT LONGWAVE TROUGH MOVING ACROSS THE CENTRAL PLAINS
AND GREAT LAKES STATES. MODERATE TO HIGH CONFIDENCE EXISTS IN THE
ONGOING FORECAST FOR UPPER MI UNTIL SUNDAY. OTHERWISE THE CONSENSUS
FOR MONDAY-TUESDAY WOULD BE FOR AT LEAST SOME COOLER WITH 850MB
TEMPS FALLING AGAIN TO -10 TO -12C.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 558 PM EST TUE JAN 19 2016
AS THE LLVL FLOW BACKS TOWARD THE SW THE REMAINDER OF THIS AFTN AND
DRAWS DRIER AIR INTO UPR MI...EXPECT LINGERING LO CLDS/-SHSN/MVFR
CONDITIONS AT SAW TO GIVE WAY TO VFR WX AND WILL STAY VFR THROUGH
THE PERIOD AT IWD. THE LO CLDS/-SHSN AND MVFR/TEMPO IFR CONDITIONS
AT CMX WL LINGER LONGER...BUT EVEN THERE THE FLOW WL BACK ENUF TO
RESULT IN PREDOMINANT VFR CONDITIONS BY MID/LATE EVNG.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 354 PM EST TUE JAN 19 2016
WITH A RELATIVELY WEAK PRES GRADIENT EXPECTED OVER THE UPPER LAKES
MOST OF THIS COMING FORECAST PERIOD...WINDS WILL REMAIN UNDER 25 KTS
MOST OF THE TIME. THE BEST CHANCE FOR SW WINDS UP TO 30 KTS WILL BE
ON SAT...WHEN A SHARPER GRADIENT BETWEEN HI PRES STRETCHING FROM NEW
ENGLAND INTO THE MID MS RIVER VALLEY AND A LO PRES TROF APPROACHING
FROM THE NW MAY SUPPORT THE STRONGER WINDS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...KF
AVIATION...07
MARINE...KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
449 PM EST TUE JAN 19 2016
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 354 PM EST TUE JAN 19 2016
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW SHRTWV RDG
STRETCHING FM NW ONTARIO IN MN WITHIN NW FLOW ALF ON WRN FLANK OF
DEPARTING UPR LO OVER SE CANADA. ASSOCIATED SFC HI PRES RDG
STRETCHES FM NW ONTARIO THRU THE UPR MS RIVER VALLEY AND TOWARD THE
OH RIVER VALLEY. NW FLOW OF COLD AIR...WITH H925 TEMPS ARND -15C
OVER THE UPR LKS...IN ADVANCE OF THIS SLOWLY APRCHG RDG IS STILL
CAUSING SOME LES...BUT BANDS ARE WEAKER/MORE DISORGANIZED WITH
STRONG SUBSIDENCE ASSOCIATED WITH THE APRCHG RDG LOWERING INVRN BASE
TOWARD 3-4K FT AGL PER MQT VWP. LLVL WINDS ARE BEGINNING TO BACK AS
WELL AHEAD OF THE APRCHG SFC RDG...SO BANDS ARE SHIFTING/LIMITING
RESIDENCE TIME. PLENTY OF LO CLDS LINGER UNDER THE LOWERING INVRN
DESPITE DRY NATURE OF THE NEAR SFC LYR UPSTREAM /WHERE SFC DEWPTS
ARE AOB -20F OVER MUCH OF NRN MN...BUT SOME BREAKS ARE BEGINNING TO
SHOW UP OVER THE FAR W NEAR IWD CLOSER TO THE INCOMING SFC HI PRES/
DRY LLVL AIR AND OVER THE SCENTRL WHERE NW FLOW IS DOWNSLOPING.
THERE IS ANOTHER SHRTWV STRETCHING FM SASKATCHEWAN INTO THE NRN
PLAINS THAT IS DIGGING SEWD...AND SOME HI/MID CLDS AHEAD OF THIS
DISTURBANCE ARE SPREADING INTO MN.
MAIN FCST CONCERNS IN THE SHORT TERM FOCUS ON LINGERING LES TRENDS/
LO CLDS AND IMPACT ON TEMPS.
TNGT...SFC HI PRES RDG AXIS IS FCST TO SHIFT SLOWLY TO THE E AND
STRETCH FM THE UPR OH VALLEY INTO UPR MI AT 12Z WED. AS THE LLVL
WINDS CONTINUE TO BACK TOWARD THE WSW...ANY LINGERING SN SHOWERS
OVER THE NRN KEWEENAW AND NEAR LK SUP E OF GRAND MARAIS SHOULD LIFT
OUT INTO LK SUP. SINCE THE WINDS WL SHIFT OFFSHORE AND THE INVRN
BASE WL LOWER WITH MORE ACYC LLVL FLOW...EXPECT THE BULK OF THE LO
CLDS TO SHIFT OVER THE LK AS WELL. ALTHOUGH THE SETUP SEEMS
FAVORABLE FOR VERY LO TEMPS WITH LGT OFFSHORE WINDS...MID/HI CLDS ON
THE NRN FRINGES OF SHRTWV DIGGING TO THE SE ARE FCST TO MOVE OVER
THE CWA AND LIMIT THE DIURNAL TEMP FALL. SO ALTHOUGH THERE MAY BE
SOME SUB ZERO MIN TEMPS OVER THE INTERIOR...WIDESPREAD MIN TEMPS
UNDER -10F AS OBSVD THIS MRNG OVER NRN MN ARE NOT LIKELY.
WED...LARGE SCALE QVECTOR DVGC AHEAD OF SHRTWV RDG AND UNDER SFC RDG
AXIS WL MAINTAIN MAINLY DRY WX FOR MOST OF THE CWA...WITH ANY SN
SHOWERS OVER LK SUP NEAR LK INDUCED TROF FCST TO LINGER OVER THE N
HALF OF THE LK. DURING THE DAY...MANY OF THE MODELS SHOW SOME MSTR
RETURN OVER MAINLY THE WRN CWA IN THE SW FLOW BTWN THE SFC RDG
SHIFTING SLOWLY TO THE E AND A SHRTWV APRCHG LATE IN THE DAY FM THE
NW. BUT SINCE ANY FORCING AND LLVL MSTR INFLOW WL BE MINIMAL...OPTED
TO RETAIN ONLY SCHC POPS OVER THE WRN CWA WHERE THE MOISTENING IS
FCST TO BE A BIT MORE ROBUST. EXPECT A SOMEWHAT WARMER AFTN WITH H85
TEMPS REBOUNDING TO ARND -12C BY 00Z THU.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 446 PM EST TUE JAN 19 2016
BY 00Z THURSDAY THE SFC HIGH WILL HAVE SLIPPED TO IL-OH...WITH A
WEAK RIDGE/LAKE INDUCED LOW SLOWLY DEEPENING ACROSS LAKE SUPERIOR AS
THE RIDGE EXITS. THE NEXT IN A SERIES OF SHORTWAVES WILL ASSIST IN
THE LIGHT SNOW SHOWER POTENTIAL WEDNESDAY NIGHT...TRACKING FROM SW
ONTARIO AT 00Z TO FAR N LAKE HURON BY DAYBREAK THURSDAY. THE MAIN
IMPACT WILL BE TO INCREASE NW FLOW ACROSS THE KEWEENAW PENINSULA
BEHIND THE WEAK SFC-500MB TROUGH AND ENHANCING LIGHT SNOW SHOWERS
THERE. 850MB TEMPS WILL BE AROUND -11C. NOT EXPECTING ADVISORY
SNOW AMOUNTS AT THIS TIME.
THE NEXT SFC HIGH SITUATED OVER MANITOBA AND N DAKOTA THURSDAY WILL
PUSH ACROSS MN AND W LAKE SUPERIOR ON FRIDAY...BUT WILL ONLY SLOWLY
BREAK DOWN THE LINGERING WEAK TROUGH OVER E LAKE SUPERIOR/E UPPER MI
BY FRIDAY NIGHT. SFC WINDS WILL SHIFT OUT OF THE N THURSDAY NIGHT
THROUGH FRIDAY AND 850MB TEMPS WILL FALL TO -12 TO -14C...BUT WITH
LIMITED MOISTURE...EXPECT SNOWFALL LESS THAN 2IN.
ANOTHER DRY PERIOD IS EXPECTED FRIDAY NIGHT THROUGH SATURDAY NIGHT
AS ANOTHER AREA OF HIGH PRESSURE SHIFTS ACROSS THE REGION. BY
SATURDAY MORNING ...THE NEXT LOW WILL BET SET UP ACROSS S CENTRAL
CANADA WHILE MUCH OF THE ATTENTION WILL BE ON THE TRACK AND TIMING
OF THE LOW OFF THE MID ATLANTIC COAST. UPPER MI WILL REMAIN IN
BETWEEN SYSTEMS UNTIL THE CANADIAN LOW SHIFTS ACROSS ONTARIO SUNDAY
AND THE EASTERN LOW MOVES OFF THE NEW ENGLAND STATES. THE TROUGH
LOOKS TO CROSS UPPER MI LATE SUNDAY NIGHT/MONDAY MORNING. THE GFS
AND ECMWF ARE OVER 12HRS ON TIMING WHEN THE NEXT SWATH OF SNOW WILL
CROSS UPPER MI SUNDAY AFTERNOON-MONDAY...WITH DIFFERENCES IN THE
TIMING OF THE NEXT LONGWAVE TROUGH MOVING ACROSS THE CENTRAL PLAINS
AND GREAT LAKES STATES. MODERATE TO HIGH CONFIDENCE EXISTS IN THE
ONGOING FORECAST FOR UPPER MI UNTIL SUNDAY. OTHERWISE THE CONSENSUS
FOR MONDAY-TUESDAY WOULD BE FOR AT LEAST SOME COOLER WITH 850MB
TEMPS FALLING AGAIN TO -10 TO -12C.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1249 PM EST TUE JAN 19 2016
AS THE LLVL FLOW BACKS TOWARD THE SW THE REMAINDER OF THIS AFTN AND
DRAWS DRIER AIR INTO UPR MI...EXPECT LINGERING LO CLDS/-SHSN/MVFR
CONDITIONS AT IWD AND SAW TO GIVE WAY TO VFR WX. THE LO CLDS/-SHSN
AND MVFR/TEMPO IFR CONDITIONS AT CMX WL LINGER LONGER...BUT EVEN
THERE THE FLOW WL BACK ENUF TO RESULT IN PREDOMINANT VFR CONDITIONS
BY MID/LATE EVNG. SOME MVFR CLDS MAY RETURN TO IWD LATE IN THE TAF
PERIOD AHEAD OF A WEAK DISTURBANCE...BUT FCST CONTINUED VFR CIGS IN
THE ABSENCE OF SGNFT MSTR RETURN.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 354 PM EST TUE JAN 19 2016
WITH A RELATIVELY WEAK PRES GRADIENT EXPECTED OVER THE UPPER LAKES
MOST OF THIS COMING FORECAST PERIOD...WINDS WILL REMAIN UNDER 25 KTS
MOST OF THE TIME. THE BEST CHANCE FOR SW WINDS UP TO 30 KTS WILL BE
ON SAT...WHEN A SHARPER GRADIENT BETWEEN HI PRES STRETCHING FROM NEW
ENGLAND INTO THE MID MS RIVER VALLEY AND A LO PRES TROF APPROACHING
FROM THE NW MAY SUPPORT THE STRONGER WINDS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...KF
AVIATION...KC
MARINE...KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
354 PM EST TUE JAN 19 2016
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 354 PM EST TUE JAN 19 2016
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW SHRTWV RDG
STRETCHING FM NW ONTARIO IN MN WITHIN NW FLOW ALF ON WRN FLANK OF
DEPARTING UPR LO OVER SE CANADA. ASSOCIATED SFC HI PRES RDG
STRETCHES FM NW ONTARIO THRU THE UPR MS RIVER VALLEY AND TOWARD THE
OH RIVER VALLEY. NW FLOW OF COLD AIR...WITH H925 TEMPS ARND -15C
OVER THE UPR LKS...IN ADVANCE OF THIS SLOWLY APRCHG RDG IS STILL
CAUSING SOME LES...BUT BANDS ARE WEAKER/MORE DISORGANIZED WITH
STRONG SUBSIDENCE ASSOCIATED WITH THE APRCHG RDG LOWERING INVRN BASE
TOWARD 3-4K FT AGL PER MQT VWP. LLVL WINDS ARE BEGINNING TO BACK AS
WELL AHEAD OF THE APRCHG SFC RDG...SO BANDS ARE SHIFTING/LIMITING
RESIDENCE TIME. PLENTY OF LO CLDS LINGER UNDER THE LOWERING INVRN
DESPITE DRY NATURE OF THE NEAR SFC LYR UPSTREAM /WHERE SFC DEWPTS
ARE AOB -20F OVER MUCH OF NRN MN...BUT SOME BREAKS ARE BEGINNING TO
SHOW UP OVER THE FAR W NEAR IWD CLOSER TO THE INCOMING SFC HI PRES/
DRY LLVL AIR AND OVER THE SCENTRL WHERE NW FLOW IS DOWNSLOPING.
THERE IS ANOTHER SHRTWV STRETCHING FM SASKATCHEWAN INTO THE NRN
PLAINS THAT IS DIGGING SEWD...AND SOME HI/MID CLDS AHEAD OF THIS
DISTURBANCE ARE SPREADING INTO MN.
MAIN FCST CONCERNS IN THE SHORT TERM FOCUS ON LINGERING LES TRENDS/
LO CLDS AND IMPACT ON TEMPS.
TNGT...SFC HI PRES RDG AXIS IS FCST TO SHIFT SLOWLY TO THE E AND
STRETCH FM THE UPR OH VALLEY INTO UPR MI AT 12Z WED. AS THE LLVL
WINDS CONTINUE TO BACK TOWARD THE WSW...ANY LINGERING SN SHOWERS
OVER THE NRN KEWEENAW AND NEAR LK SUP E OF GRAND MARAIS SHOULD LIFT
OUT INTO LK SUP. SINCE THE WINDS WL SHIFT OFFSHORE AND THE INVRN
BASE WL LOWER WITH MORE ACYC LLVL FLOW...EXPECT THE BULK OF THE LO
CLDS TO SHIFT OVER THE LK AS WELL. ALTHOUGH THE SETUP SEEMS
FAVORABLE FOR VERY LO TEMPS WITH LGT OFFSHORE WINDS...MID/HI CLDS ON
THE NRN FRINGES OF SHRTWV DIGGING TO THE SE ARE FCST TO MOVE OVER
THE CWA AND LIMIT THE DIURNAL TEMP FALL. SO ALTHOUGH THERE MAY BE
SOME SUB ZERO MIN TEMPS OVER THE INTERIOR...WIDESPREAD MIN TEMPS
UNDER -10F AS OBSVD THIS MRNG OVER NRN MN ARE NOT LIKELY.
WED...LARGE SCALE QVECTOR DVGC AHEAD OF SHRTWV RDG AND UNDER SFC RDG
AXIS WL MAINTAIN MAINLY DRY WX FOR MOST OF THE CWA...WITH ANY SN
SHOWERS OVER LK SUP NEAR LK INDUCED TROF FCST TO LINGER OVER THE N
HALF OF THE LK. DURING THE DAY...MANY OF THE MODELS SHOW SOME MSTR
RETURN OVER MAINLY THE WRN CWA IN THE SW FLOW BTWN THE SFC RDG
SHIFTING SLOWLY TO THE E AND A SHRTWV APRCHG LATE IN THE DAY FM THE
NW. BUT SINCE ANY FORCING AND LLVL MSTR INFLOW WL BE MINIMAL...OPTED
TO RETAIN ONLY SCHC POPS OVER THE WRN CWA WHERE THE MOISTENING IS
FCST TO BE A BIT MORE ROBUST. EXPECT A SOMEWHAT WARMER AFTN WITH H85
TEMPS REBOUNDING TO ARND -12C BY 00Z THU.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 350 AM EST TUE JAN 19 2016
...SMALL CHANCES OF SNOW THROUGH THE WEEK WITH A WARMING TREND BY
THE WEEKEND...
UPPER LOW AND CORE OF THE COLD WILL BE OVER FAR EASTERN CANADA
AROUND LABRADOR ON WED WHILE WNW FLOW ALOFT BRINGS WARMER AIR ALOFT
FM WESTERN CANADA TO GREAT LAKES. NW FLOW PERSISTS THROUGH LATE WEEK
BUT SYSTEMS WITHIN THIS FLOW LOOK TO REMAIN WEAK. LATER THU INTO
FRI...A MUCH STRONGER TROUGH ALOFT TAKES SHAPE OVER SOUTHERN PLAINS
AND THOUGH THIS SYSTEM WILL STAY WELL TO SOUTH OF GREAT LAKES...IT
COULD BECOME SIGNIFICANT WINTER STORM FOR THE MID ATLANTIC THIS
WEEKEND. AS THAT IS OCCURRING THERE...RIDGING WILL BE BUILDING FM
THE WESTERN CONUS INTO THE MID CONUS AND WESTERN GREAT LAKES. THERMAL
RIDGE POKES ACROSS UPPER LAKES ON SAT INTO SUN WHEN TEMPS COULD REACH
NEAR 30 DEGREES...THEN TURNS COOLER BY MON IN WAKE OF A COLD FRONT.
OVERALL NOT A LOT OF OPPORTUNTIES FOR MUCH SNOW IN THE EXPECTED
PATTERN...EITHER WIDESPREAD SYSTEM TYPE OR LAKE EFFECT...BUT THERE
WILL BE SOME CHANCES FOR LIGHT SNOW. FIRST ON WED...SHORTWAVE TROUGH
CURRENTLY CROSSING NORTHERN PLAINS WILL BE BRINGING LIGHT SNOW FROM
ILL TO LOWER MI. OVER UPR MICHIGAN...DRY AIR BLO 10KFT WILL PROHIBIT
MUCH SNOWFALL TO START BUT THEN MOISTURE INCREASES THROUGH THE DAY.
LIFT REMAINS WEAK THOUGH SO STILL NOT LOOKING AT EVEN AN INCH OF
SNOW WITH THIS SYSTEM ANYWHERE IN THE CWA. ANOTHER WEAKER SYSTEM
CROSSES NW ONTARIO AND THE UPPER GREAT LAKES WED NIGHT INTO THU.
BEST FORCING STAYS OVER LK SUPERIOR AND INTO NW ONTARIO...BUT WEAK
SFC TROUGH TIED TO THE SHORTWAVE COULD BRING LIGHT SNOW TO KEWEENAW.
AS TROUGH MOVES THROUGH...MAY SEE LIGHT LAKE EFFECT SNOW SHOWERS THU
NIGHT INTO FRI WITH H85 TEMPS DOWN TO AROUND -13C AND MAYBE AS LOW AS
-15C WHILE ANOTHER WEAKER SHORTWAVE CROSSES UPPER GREAT LAKES. LOW-
LEVEL WINDS START OUT NW IN WAKE OF TROUGH BUT BECOME NORTHERLY BY
FRI...SO GOOD PART OF LK SUPERIOR SHORE COULD SEE LAKE EFFECT THU
NIGHT INTO FRI. GFS SOUNDINGS SHOW ALL THE MOIST LAYER WITHIN THE
DGZ...SO FLUFF FACTOR COULD BE HIGHER. BUT...MARGINALLY COLD
TEMPS...INVERSIONS LESS THAN 5KFT AND LACK OF STRONG LOW-LEVEL
CONVERGENCE SHOULD LIMIT INTENSITY OF LAKE EFFECT. INCREASED POPS
OVER CONSENSUS AS THINK THERE SHOULD BE SOME SNOW AROUND FOR THE
FAVORED LAKE EFFECT AREAS.
HIGH PRESSURE RIDGE CROSSING FRI NIGHT INTO SAT SWITCHES WINDS TO SW
AND BRINGS WARMER AIRMASS OVER THE UPPER GREAT LAKES...SO LAKE
EFFECT WILL END. H85 TEMPS AROUND -10C FRI NIGHT WARM TO -6C BY SAT
MORNING AND -2C BY SAT EVENING. SKIES ON SAT SHOULD START OUT MOSTLY
SUNNY THEN THERE WILL BE THICKENING MID-HIGH CLOUDS IN THE AFTN
AHEAD OF ANOTHER SHORTWAVE TROUGH AND WEAK WAVE OF LOW PRES CROSSING
NORTHERN PLAINS INTO NW ONTARIO. SOUNDINGS INDICATE SHALLOW MIXING
HEIGHTS OF 950MB-925MB ON SAT BUT WITH GOOD DEAL OF SUNSHINE...COULD
BE HIGHER. SHALLOW MIXING SUPPORTS HIGHS INTO THE UPPER 20S.
SLIGHTLY DEEPER MIXING TO 900MB WOULD YIELD HIGHS INTO THE MID-UPR
30S. DEEPER MIXING COULD TAP INTO PORTION OF 30-40 KT WINDS ALOFT.
ATTM LOOKS LIKE MAX CORE OF WINDS WILL STAY ABOVE INVERION...BUT
STILL COULD BE BREEZY BY AFTN DUE TO THE TIGHTER PRESSURE GRADIENT
BTWN THE EXITING RIDGE AND SFC LOW/COLD FRONT SCNTRL CANADA TO
NORTHERN PLAINS. NUDGED MAX TEMPS UPWARD OVER CONSENSUS BUT ONLY
INTO THE LOW 30S AT THE WARMEST. AS THAT SYSTEM MOVES INTO NW
ONTARIO MAY SEE LIGHT SNOW OR FLURRIES OVER UPR MICHIGAN. MODELS NOT
VERY CONSISTENT ON THAT IDEA...BUT WORTHY OF LOW CHANCES ESPECIALLY
NORTH CWA AND OUT ACROSS LK SUPERIOR.
MAY SEE ANOTHER ROUND OF LIGHT LAKE EFFECT SNOW SUN NIGHT INTO MON
AND THERE ARE SOME INDICATIONS OF ANOTHER SHORTWAVE MOVING THROUGH
WITH A WAVE OF LIGHT SNOW OVER UPPER GREAT LAKES. PLENTY OF TIME FOR
DETAILS TO CHANGE...BUT AT THIS TIME NOT LOOKING LIKE MUCH SNOW.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1249 PM EST TUE JAN 19 2016
AS THE LLVL FLOW BACKS TOWARD THE SW THE REMAINDER OF THIS AFTN AND
DRAWS DRIER AIR INTO UPR MI...EXPECT LINGERING LO CLDS/-SHSN/MVFR
CONDITIONS AT IWD AND SAW TO GIVE WAY TO VFR WX. THE LO CLDS/-SHSN
AND MVFR/TEMPO IFR CONDITIONS AT CMX WL LINGER LONGER...BUT EVEN
THERE THE FLOW WL BACK ENUF TO RESULT IN PREDOMINANT VFR CONDITIONS
BY MID/LATE EVNG. SOME MVFR CLDS MAY RETURN TO IWD LATE IN THE TAF
PERIOD AHEAD OF A WEAK DISTURBANCE...BUT FCST CONTINUED VFR CIGS IN
THE ABSENCE OF SGNFT MSTR RETURN.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 354 PM EST TUE JAN 19 2016
WITH A RELATIVELY WEAK PRES GRADIENT EXPECTED OVER THE UPPER LAKES
MOST OF THIS COMING FORECAST PERIOD...WINDS WILL REMAIN UNDER 25 KTS
MOST OF THE TIME. THE BEST CHANCE FOR SW WINDS UP TO 30 KTS WILL BE
ON SAT...WHEN A SHARPER GRADIENT BETWEEN HI PRES STRETCHING FROM NEW
ENGLAND INTO THE MID MS RIVER VALLEY AND A LO PRES TROF APPROACHING
FROM THE NW MAY SUPPORT THE STRONGER WINDS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...JLA
AVIATION...KC
MARINE...KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
357 AM EST TUE JAN 19 2016
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 410 PM EST MON JAN 18 2016
WV IMAGERY AND RAP ANALYSIS INDICATED A MID/UPPER LEVEL LOW FROM THE
ERN LAKES INTO NRN NEW ENGLAND WITH A SHORTWAVE TROUGH EXTENDING NW
TO NEAR LAKE SUPERIOR. AT THE SFC...A LAKES AGGREGATE TROUGH EXTENDED
FROM LAKE HURON INTO SRN LAKE SUPERIOR. MULTIPLE WIND PARALLEL LES
BANDS WITH NW ARCTIC FLOW CONTINUED. 850 MB TEMPS AROUND -23C
PROVIDED PLENTIFUL INSTABILITY WITH LAKE INDUCED CAPES INTO THE
500-750 J/KG. THE MID LEVEL SHRTWV AND ASSOCIATED 700-300 MB QVECTOR
CONV HAS ALSO HELPED BOOST INVERSION/EQUILIBRIUM HEIGHTS THIS
AFTERNOON. VIS LOOP...SFC OBS AND WEB CAMS SUGGEST THE HEAVIER LES
WAS OVER THE ERN CWA...IN CLOSER PROXIMITY TO THE SHRTWV AND
DOWNSTREAM FROM THE LONGEST FETCH.
TONIGHT...THE HIGH RES MODELS SUGGEST THAT LOW LEVEL WINDS WILL VEER
SLIGHTLY IN THE WAKE OF THE SHRTWV...HELPING TO PUSH THE MORE
PROMINENT LES BANDS INTO CNTRL AND WRN ALGER COUNTY. WITH ADDITIONAL
SNOWFALL AMOUNTS IN THE 3 TO 7 INCH RANGE EXPECTED...THE LES WARNING
WAS EXTENDED (TIL 12Z) FOR ALGER AND NRN SCHOOLCRAFT COUNTIES WITH
AN THE ADVY INTO SRN SCHOOLCRAFT ALSO EXTENDED TIL 06Z.
OVER THE WEST...INVERSION HEIGHTS DROP OFF TO AROUND 4K FT THIS
EVENING WHICH SHOULD LIMIT LES INTENSITY WITH ADDITIONAL SNOWFALL
AMOUNTS TO ADVY AMOUNTS IN THE 2 TO 5 INCH RANGE OR LESS. THE
STRONGER LOW LEVEL CONV FROM ONTONAGON EASTWARD SHOULD ALSO SAG TO
THE SOUTH THIS EVENING.
TUE...LES SHOULD CONTINUE TO DIMINISH WITH INVERSION HEIGHTS FALLING
TO 3K-4K FT AND WINDS BACKING ACYC WRLY AS A SFC RIDGE BUILDS FROM
THE UPPER MS VALLEY INTO THE WRN LAKES. TEMPS WILL ALSO MODERATE
WITH HIGHS FROM THE LOWER TEENS WEST TO AROUND 20 EAST.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 350 AM EST TUE JAN 19 2016
...SMALL CHANCES OF SNOW THROUGH THE WEEK WITH A WARMING TREND BY
THE WEEKEND...
UPPER LOW AND CORE OF THE COLD WILL BE OVER FAR EASTERN CANADA
AROUND LABRADOR ON WED WHILE WNW FLOW ALOFT BRINGS WARMER AIR ALOFT
FM WESTERN CANADA TO GREAT LAKES. NW FLOW PERSISTS THROUGH LATE WEEK
BUT SYSTEMS WITHIN THIS FLOW LOOK TO REMAIN WEAK. LATER THU INTO
FRI...A MUCH STRONGER TROUGH ALOFT TAKES SHAPE OVER SOUTHERN PLAINS
AND THOUGH THIS SYSTEM WILL STAY WELL TO SOUTH OF GREAT LAKES...IT
COULD BECOME SIGNIFICANT WINTER STORM FOR THE MID ATLANTIC THIS
WEEKEND. AS THAT IS OCCURRING THERE...RIDGING WILL BE BUILDING FM
THE WESTERN CONUS INTO THE MID CONUS AND WESTERN GREAT LAKES. THERMAL
RIDGE POKES ACROSS UPPER LAKES ON SAT INTO SUN WHEN TEMPS COULD REACH
NEAR 30 DEGREES...THEN TURNS COOLER BY MON IN WAKE OF A COLD FRONT.
OVERALL NOT A LOT OF OPPORTUNTIES FOR MUCH SNOW IN THE EXPECTED
PATTERN...EITHER WIDESPREAD SYSTEM TYPE OR LAKE EFFECT...BUT THERE
WILL BE SOME CHANCES FOR LIGHT SNOW. FIRST ON WED...SHORTWAVE TROUGH
CURRENTLY CROSSING NORTHERN PLAINS WILL BE BRINGING LIGHT SNOW FROM
ILL TO LOWER MI. OVER UPR MICHIGAN...DRY AIR BLO 10KFT WILL PROHIBIT
MUCH SNOWFALL TO START BUT THEN MOISTURE INCREASES THROUGH THE DAY.
LIFT REMAINS WEAK THOUGH SO STILL NOT LOOKING AT EVEN AN INCH OF
SNOW WITH THIS SYSTEM ANYWHERE IN THE CWA. ANOTHER WEAKER SYSTEM
CROSSES NW ONTARIO AND THE UPPER GREAT LAKES WED NIGHT INTO THU.
BEST FORCING STAYS OVER LK SUPERIOR AND INTO NW ONTARIO...BUT WEAK
SFC TROUGH TIED TO THE SHORTWAVE COULD BRING LIGHT SNOW TO KEWEENAW.
AS TROUGH MOVES THROUGH...MAY SEE LIGHT LAKE EFFECT SNOW SHOWERS THU
NIGHT INTO FRI WITH H85 TEMPS DOWN TO AROUND -13C AND MAYBE AS LOW AS
-15C WHILE ANOTHER WEAKER SHORTWAVE CROSSES UPPER GREAT LAKES. LOW-
LEVEL WINDS START OUT NW IN WAKE OF TROUGH BUT BECOME NORTHERLY BY
FRI...SO GOOD PART OF LK SUPERIOR SHORE COULD SEE LAKE EFFECT THU
NIGHT INTO FRI. GFS SOUNDINGS SHOW ALL THE MOIST LAYER WITHIN THE
DGZ...SO FLUFF FACTOR COULD BE HIGHER. BUT...MARGINALLY COLD
TEMPS...INVERSIONS LESS THAN 5KFT AND LACK OF STRONG LOW-LEVEL
CONVERGENCE SHOULD LIMIT INTENSITY OF LAKE EFFECT. INCREASED POPS
OVER CONSENSUS AS THINK THERE SHOULD BE SOME SNOW AROUND FOR THE
FAVORED LAKE EFFECT AREAS.
HIGH PRESSURE RIDGE CROSSING FRI NIGHT INTO SAT SWITCHES WINDS TO SW
AND BRINGS WARMER AIRMASS OVER THE UPPER GREAT LAKES...SO LAKE
EFFECT WILL END. H85 TEMPS AROUND -10C FRI NIGHT WARM TO -6C BY SAT
MORNING AND -2C BY SAT EVENING. SKIES ON SAT SHOULD START OUT MOSTLY
SUNNY THEN THERE WILL BE THICKENING MID-HIGH CLOUDS IN THE AFTN
AHEAD OF ANOTHER SHORTWAVE TROUGH AND WEAK WAVE OF LOW PRES CROSSING
NORTHERN PLAINS INTO NW ONTARIO. SOUNDINGS INDICATE SHALLOW MIXING
HEIGHTS OF 950MB-925MB ON SAT BUT WITH GOOD DEAL OF SUNSHINE...COULD
BE HIGHER. SHALLOW MIXING SUPPORTS HIGHS INTO THE UPPER 20S.
SLIGHTLY DEEPER MIXING TO 900MB WOULD YIELD HIGHS INTO THE MID-UPR
30S. DEEPER MIXING COULD TAP INTO PORTION OF 30-40 KT WINDS ALOFT.
ATTM LOOKS LIKE MAX CORE OF WINDS WILL STAY ABOVE INVERION...BUT
STILL COULD BE BREEZY BY AFTN DUE TO THE TIGHTER PRESSURE GRADIENT
BTWN THE EXITING RIDGE AND SFC LOW/COLD FRONT SCNTRL CANADA TO
NORTHERN PLAINS. NUDGED MAX TEMPS UPWARD OVER CONSENSUS BUT ONLY
INTO THE LOW 30S AT THE WARMEST. AS THAT SYSTEM MOVES INTO NW
ONTARIO MAY SEE LIGHT SNOW OR FLURRIES OVER UPR MICHIGAN. MODELS NOT
VERY CONSISTENT ON THAT IDEA...BUT WORTHY OF LOW CHANCES ESPECIALLY
NORTH CWA AND OUT ACROSS LK SUPERIOR.
MAY SEE ANOTHER ROUND OF LIGHT LAKE EFFECT SNOW SUN NIGHT INTO MON
AND THERE ARE SOME INDICATIONS OF ANOTHER SHORTWAVE MOVING THROUGH
WITH A WAVE OF LIGHT SNOW OVER UPPER GREAT LAKES. PLENTY OF TIME FOR
DETAILS TO CHANGE...BUT AT THIS TIME NOT LOOKING LIKE MUCH SNOW.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 104 AM EST TUE JAN 19 2016
AT KIWD...EXPECT IFR/MVFR VSBY DURING THE HEAVIER SNOW BANDS AT IWD
EARLY IN THIS FORECAST...BUT THEN WINDS BACKING LATE TONIGHT WILL
ALLOW FOR IMPROVEMENT TO PREVAILING MVFR CONDITIONS IN LIGHTER LAKE
EFFECT SHOWERS. EXPECT A RETURN TO VFR CONDITIONS TUE AFTERNOON AS
WINDS BACK TO THE SW.
AT KCMX...CONTINUED LAKE EFFECT SNOW SHOWERS WILL STILL RESULT IN
PREVAILING LOW MVFR/IFR CONDITIONS THROUGH TUE AFTERNOON BEFORE MVFR
CONDITIONS RETURN BY TUE NIGHT.
AT KSAW...EXPECT MVFR EARLY IN THE PERIOD AS SOME LIGHT LAKE EFFECT
SNOW BRUSHES THE AREA. BACKING WINDS LATE TONIGHT WILL ALLOW
IMPROVEMENT AGAIN TO VFR.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 410 PM EST MON JAN 18 2016
EXPECT WINDS TO DIMINISH LATER THIS EVENING TO 20-25 KTS...HIGHEST
OVER ERN LAKE SUPERIOR. IN ADDITION...HEAVY FREEZING SPRAY IS
EXPECTED WILL ALSO END EARLY THIS EVENING. WINDS ARE EXPECTED TO
SLOWLY DIMINISH TOWARDS THE MIDDLE OF THE WEEK...AS HIGH PRESSURE
MOVES OVER THE UPPER GREAT LAKES REGION.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...JLA
AVIATION...07
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
110 AM EST TUE JAN 19 2016
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 410 PM EST MON JAN 18 2016
WV IMAGERY AND RAP ANALYSIS INDICATED A MID/UPPER LEVEL LOW FROM THE
ERN LAKES INTO NRN NEW ENGLAND WITH A SHORTWAVE TROUGH EXTENDING NW
TO NEAR LAKE SUPERIOR. AT THE SFC...A LAKES AGGREGATE TROUGH EXTENDED
FROM LAKE HURON INTO SRN LAKE SUPERIOR. MULTIPLE WIND PARALLEL LES
BANDS WITH NW ARCTIC FLOW CONTINUED. 850 MB TEMPS AROUND -23C
PROVIDED PLENTIFUL INSTABILITY WITH LAKE INDUCED CAPES INTO THE
500-750 J/KG. THE MID LEVEL SHRTWV AND ASSOCIATED 700-300 MB QVECTOR
CONV HAS ALSO HELPED BOOST INVERSION/EQUILIBRIUM HEIGHTS THIS
AFTERNOON. VIS LOOP...SFC OBS AND WEB CAMS SUGGEST THE HEAVIER LES
WAS OVER THE ERN CWA...IN CLOSER PROXIMITY TO THE SHRTWV AND
DOWNSTREAM FROM THE LONGEST FETCH.
TONIGHT...THE HIGH RES MODELS SUGGEST THAT LOW LEVEL WINDS WILL VEER
SLIGHTLY IN THE WAKE OF THE SHRTWV...HELPING TO PUSH THE MORE
PROMINENT LES BANDS INTO CNTRL AND WRN ALGER COUNTY. WITH ADDITIONAL
SNOWFALL AMOUNTS IN THE 3 TO 7 INCH RANGE EXPECTED...THE LES WARNING
WAS EXTENDED (TIL 12Z) FOR ALGER AND NRN SCHOOLCRAFT COUNTIES WITH
AN THE ADVY INTO SRN SCHOOLCRAFT ALSO EXTENDED TIL 06Z.
OVER THE WEST...INVERSION HEIGHTS DROP OFF TO AROUND 4K FT THIS
EVENING WHICH SHOULD LIMIT LES INTENSITY WITH ADDITIONAL SNOWFALL
AMOUNTS TO ADVY AMOUNTS IN THE 2 TO 5 INCH RANGE OR LESS. THE
STRONGER LOW LEVEL CONV FROM ONTONAGON EASTWARD SHOULD ALSO SAG TO
THE SOUTH THIS EVENING.
TUE...LES SHOULD CONTINUE TO DIMINISH WITH INVERSION HEIGHTS FALLING
TO 3K-4K FT AND WINDS BACKING ACYC WRLY AS A SFC RIDGE BUILDS FROM
THE UPPER MS VALLEY INTO THE WRN LAKES. TEMPS WILL ALSO MODERATE
WITH HIGHS FROM THE LOWER TEENS WEST TO AROUND 20 EAST.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 324 PM EST MON JAN 18 2016
THE 500MB RIDGE OVERHEAD ON TUESDAY WILL SLOWLY EXIT E TUESDAY NIGHT
AND WEDNESDAY IN RESPONSE TO THE ELONGATED TROUGH EXTENDING FROM S
CENTRAL CANADA THROUGH W MN AND IA AT 00Z WEDNESDAY. THIS TROUGH
WILL SLIDE ACROSS THE UPPER GREAT LAKES DURING THE DAY
WEDNESDAY...AND TO THE LOWER GREAT LAKES 00-06Z THURSDAY. THIS WILL
BY WHILE THE LARGE SFC HIGH STRETCHING FROM THE UPPER GREAT LAKES TO
THE TIP OF FL AT 00Z WEDNESDAY SLOWLY BECOMES SUPRESSED TO THE SE. LOOKING
SPECIFICALLY AT THE LINGERING LAKE INDUCED TROUGH OVER LAKE
SUPERIOR...IT WILL SLOWLY DEEPEN OVERNIGHT AND INTO THURSDAY. EXPECT
LINGERING LES BANDS TO SHIFT ACROSS THE TIP OF THE KEWEENAW
PENINSULA AND FAR N LUCE COUNTY...AND EVENTUALLY OFFSHORE AS
SFC WINDS SHIFT TO A MORE S-SW DIRECTION.
A SHORTWAVE PUSHING ACROSS THE PACIFIC NORTHWEST WEDNESDAY MORNING
WILL LIVE ACROSS THE PLAINS STATES WEDNESDAY NIGHT WHILE A N WAVE
MOVES ACROSS LAKE SUPERIOR/UPPER MI. BY 00Z THURSDAY THE SFC MAP
WILL SHOW THE NEXT LOW OVER FAR E CO WILL HAVE AN INVERTED TROUGH UP
THROUGH SW MN AND W ONTARIO. THE N LOW WILL BE FAIRLY
PROGRESSIVE...MOVING OVER LAKE SUPERIOR BY 12Z THURSDAY AND EXITING
ACROSS LOWER MI THURSDAY NIGHT...MERGING WITH THE STRONGER LOW
ACROSS TN. THIS WILL BRING THE BEST CHANCE OF WIDESPREAD SNOW FOR
THIS LONG TERM PERIOD...WILL LIKELY BE LATE THURSDAY INTO EARLY
FRIDAY. AT THIS POINT THE GFS IS THE MOST ROBUST WITH THE SNOW WITH
1-4IN CWA WIDE. THE ON THE POSITIVE SIDE THE DGZ IS WITHIN THE
MOISTURE LAYER...BUT INVERSION HEIGHTS LOOK TO FALL PRETTY QUICKLY
OVERNIGHT THURSDAY NIGHT INTO FRIDAY MORNING. FAVORABLE UPSLOPE
CONDITIONS FOR LES DO NOT SEEM TO RETURN TO THE CWA UNTIL LATE
THURSDAY AFTERNOON IN THE FORM OF NW WIND BEHIND THE EXITING SFC
LOW. THEY WILL NOT BE ALL THAT STEADY FOR SIGNIFICANT DOMINANT BANDS
TO DEVELOP AS WINDS SHIFT OUT OF THE N-NNE BY DAYBREAK FRIDAY. A
GENERAL 500MB TROUGH WILL BE SETUP ACROSS THE UPPER GREAT LAKES
THROUGH THE GULF OF MEXICO W THURSDAY-FRIDAY...KEEPING COOLER AIR
OVER THE AREA. 850MB TEMPS WILL REMAIN -7 TO -14C.
LOOK FOR A SIGNIFICANT RIDGE OF HIGH PRESSURE AT 500MB FRIDAY NIGHT
TO EXTEND FROM THE INTERIOR SW UP THROUGH THE PLAINS TO PUSH INTO
THE UPPER GREAT LAKES AS THE S TROUGH DEEPENS TO A LOW AND BEGINS TO
EXIT OFF THE MID ATLANTIC SEABOARD. THIS 500MB LOW WILL PUSH N JUST
OFF THE NEW ENGLAND COAST BY SUNDAY MORNING. WAA WILL RESULT...AS
850MB TEMPS RISE TO -5 TO -10C BY 06Z SATURDAY /WARMEST OFF THE
ECMWF/...AND -1 TO -5C BY 00Z SUNDAY ON SW 850MB WINDS NEARING 35KTS.
THERE ARE SOME DIFFERENCES IN THE HANDLING OF THE 500MB LOW OVER N
CANADA FOR THE END OF THE UPCOMING WEEKEND. WHILE BOTH THE GFS AND
ECMWF SHOW A DEEP TROUGH SWINGING ACROSS MUCH OF THE NATION...THE
GFS IS FARTHER S WITH THIS FEATURE. EXPECT SOME STEADY SNOW TO SLIDE
IN FROM THE S SUNDAY EVENING INTO EARLY MONDAY...BUT TIMING AND
INTENSITY COULD CHANGE SIGNIFICANTLY BETWEEN NOW AND THEN.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 104 AM EST TUE JAN 19 2016
AT KIWD...EXPECT IFR/MVFR VSBY DURING THE HEAVIER SNOW BANDS AT IWD
EARLY IN THIS FORECAST...BUT THEN WINDS BACKING LATE TONIGHT WILL
ALLOW FOR IMPROVEMENT TO PREVAILING MVFR CONDITIONS IN LIGHTER LAKE
EFFECT SHOWERS. EXPECT A RETURN TO VFR CONDITIONS TUE AFTERNOON AS
WINDS BACK TO THE SW.
AT KCMX...CONTINUED LAKE EFFECT SNOW SHOWERS WILL STILL RESULT IN
PREVAILING LOW MVFR/IFR CONDITIONS THROUGH TUE AFTERNOON BEFORE MVFR
CONDITIONS RETURN BY TUE NIGHT.
AT KSAW...EXPECT MVFR EARLY IN THE PERIOD AS SOME LIGHT LAKE EFFECT
SNOW BRUSHES THE AREA. BACKING WINDS LATE TONIGHT WILL ALLOW
IMPROVEMENT AGAIN TO VFR. &&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 410 PM EST MON JAN 18 2016
EXPECT WINDS TO DIMINISH LATER THIS EVENING TO 20-25 KTS...HIGHEST
OVER ERN LAKE SUPERIOR. IN ADDITION...HEAVY FREEZING SPRAY IS
EXPECTED WILL ALSO END EARLY THIS EVENING. WINDS ARE EXPECTED TO
SLOWLY DIMINISH TOWARDS THE MIDDLE OF THE WEEK...AS HIGH PRESSURE
MOVES OVER THE UPPER GREAT LAKES REGION.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW WARNING UNTIL 7 AM EST THIS MORNING FOR MIZ006-
085.
LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST THIS MORNING FOR
MIZ001>003-084.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KF
AVIATION...07
MARINE...JLB
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1200 AM EST TUE JAN 19 2016
.AVIATION...
THE LAKE EFFECT SNOW BAND HAS BECOME INCREASINGLY DISORGANIZED OVER
THE PAST HOUR. A RANGE OF CIG HEIGHTS NOW EXIST OVER SOUTHEASTERN
MICHIGAN WITH MVFR STRATOCUMULUS STILL IN PLACE UNDER LAKE EFFECT
PLUME...WITH LITTLE TO NO LOW LEVEL CLOUD IN PLACE OVER THE TRI
CITIES CURRENTLY. THE STEEP LAPSE RATE STRUCTURE AND DEEP MIXED
LAYER THAT HAS BEEN IN PLACE IS FORECASTED BREAK DOWN VERY RAPIDLY
OVER THE NEXT 2-4 HOURS AS WINDS VEER WEST TO NORTHWEST. VERY SHARP
SUBSIDENCE WILL THEN PUSH DOWN INTO SOUTHEASTERN MICHIGAN IN
RESPONSE TO THE SHARP MIDLEVEL TROUGH AXIS PUSHING THROUGH THE
TERMINALS. EXPECTING GENERAL VFR CONDITIONS TUESDAY MORNING GIVING
WAY TO DIURNAL MVFR STRATOCUMULUS DEVELOPMENT.
FOR DTW...MVFR CIGS TO HOLD THROUGH MUCH OF TONIGHT BEFORE
SCATTERING AROUND DAWN. STEEP LOW LEVEL LAPSE RATES AND DIURNAL
HEATING SHOULD LEAD TO MVFR CIGS AGAIN BY 17Z.
//DTW THRESHOLD PROBABILITIES...
* HIGH FOR CEILING AOB 5000 FT THROUGH LATE TONIGHT.
* HIGH FOR SNOW AS PRECIPITATION TYPE.
&&
.PREV DISCUSSION...ISSUED 938 PM EST MON JAN 18 2016
UPDATE...
ISSUED AN UPDATE TO EXTEND THE LIGHT SNOW LIKELY WORDING ACROSS
THE INTERSTATE 96 CORRIDOR WELL THROUGH MIDNIGHT. LATEST RADAR
IMAGERY SUPPORTS THE DEVELOPMENT OF NEAR STEADY STATE LIGHT SNOW
BANDING INTO SOUTHEASTERN MICHIGAN. THE RADAR IMAGERY DOES SHOW
SNOW PRODUCTION AS HIGH AS THE 4000-6000 FT AGL LAYER...WHICH
CORRESPONDS EXACTLY TO STEEP LAPSE RATE POCKET JUST BELOW
INVERSION IN THE 00Z KDTX RAOB. THEREFORE...NOT EXPECTING
NOCTURNAL COOLING PROCESSES TO HAVE MUCH OF AN IMPACT...AND
INSTEAD WILL RELY ON CHANGE IN WIND DIRECTION. THIS IS SET TO
OCCUR WITH 1000-850 MB MEAN WIND VEERING NORTHWESTERLY IN THE
06-09Z TIMEFRAME TIED TO SHARP CYCLONIC VORTICITY FEATURE DIGGING
THROUGH. SURFACE OBSERVING SITES HAVE NOT BEEN CATCHING BULK OF
THE BAND...BUT LIMITED SURFACE SPOTTER REPORTS SUGGEST QUICK
DUSTING TYPE ACCUMULATIONS WITH RATHER MINOR DROPS IN VISIBILITY.
RATHER...THERE HAVE BEEN REPORTS OF VERY SLIPPERY CONDITIONS ALONG
THE AXIS OF LIGHT SNOWFALL...LIKELY A CONSEQUENCE OF THE COLD
TEMPERATURES AND LACK OF IMPACT FROM SALT/TREATMENT. THERE IS LOW
CONFIDENCE IN WHAT SORT OF ACCUMULATIONS WILL BE
POSSIBLE...PERHAPS UP TO AN INCH IN SOME LOCATIONS.
PREV DISCUSSION...ISSUED 350 PM EST MON JAN 18 2016
DISCUSSION...
LAKE EFFECT SNOW SHOWERS WILL HOLD WITH SCATTERED TO NUMEROUS
COVERAGE AND LIGHT TO MODERATE INTENSITY FOR THE REST OF THE
AFTERNOON THROUGH MID EVENING. THE MOST RECENT RAP SOUNDINGS
INDICATE CONVECTIVE DEPTH SETTLING STEADILY BELOW 5000 FT BETWEEN
21Z AND 03Z BUT WITH NEARLY DRY ADIABATIC LAPSE RATE AND HIGH ICE
SUPERSATURATION WITHIN THE CLOUD LAYER FOR HEALTHY GROWTH OF
DENDRITES. THAT BEING SAID...SURFACE DEWPOINT AROUND -10F REPORTED
UPSTREAM OF LAKE MICHIGAN HAS TO BE CONSIDERED A LIMITING FACTOR FOR
LAKE INDUCED CONVECTIVE POTENTIAL THIS FAR EAST. ON THE POSITIVE
SIDE...MID TO LATE AFTERNOON SURFACE OBSERVATIONS ON THIS SIDE OF
THE LAKE CONTINUE TO ADVERTISE GUSTY WEST FLOW WITH A GREATER AMOUNT
OF CONVERGENCE DOWN WIND OF LAKE MICHIGAN THAN WOULD NORMALLY BE
EXPECTED IN WELL MIXED MID AFTERNOON CONDITIONS. THIS WILL KEEP
COVERAGE WITH BETTER INTENSITY FOCUSED GENERALLY ALONG AND SOUTH OF
THE I-96 TO I-94 CORRIDOR. FACTORING IN THE DRY NATURE OF THE ARCTIC
AIR AND STEADILY SHRINKING CONVECTIVE DEPTH...EXPECT ACCUMULATION
LIMITED TO LESS THAN AN INCH EVEN WITH NUMEROUS COVERAGE AND/OR A
STREAMER OF GREATER FOCUSED BANDING AT TIMES BEFORE DIMINISHING
TOWARD MIDNIGHT.
THE UPPER LEVEL TROUGH WILL SWING SOUTH OF LOWER MICHIGAN SHORTLY
AFTER MIDNIGHT AND WILL SHUT DOWN LAKE EFFECT PRODUCTION. STRONG
SUBSIDENCE TRAILING THE UPPER TROUGH AND PRECEDING THE RIDGE AXIS
WILL ALSO SUPPORT A CLEARING TREND MUCH LIKE WHAT OCCURRED EARLY
THIS MORNING. THIS WILL ALLOW ANOTHER ROUND OF SINGLE DIGIT MIN
TEMPS OUTSIDE OF METRO DETROIT AND MAINTAIN WIND CHILL NEAR 10
BELOW AT TIMES THROUGH TUESDAY MORNING. FORECAST CONCERNS WILL THEN
BE REDUCED TO CLOUD AND TEMPERATURE TRENDS DURING THE REST OF
TUESDAY AND TUESDAY NIGHT. BACKING LOW LEVEL FLOW WILL DIRECT
REMAINING LAKE EFFECT CLOUDS MAINLY INTO THE TRI CITIES BEFORE HIGH
PRESSURE BUILDS OVER THE REGION BY EVENING. LIGHTER WIND WILL MAKE
MAX TEMPS IN THE LOWER 20S EASIER TO TAKE COMPARED TO RECENT DAYS.
BENIGN CONDITIONS WILL CONTINUE THROUGH TUESDAY NIGHT AS HIGH CLOUDS
THICKEN AND LOWER IN ADVANCE OF THE NEXT LOW PRESSURE SYSTEM. THE
NEW MODEL PACKAGE IS IN GOOD AGREEMENT HOLDING OFF SNOW UNTIL
WEDNESDAY MORNING...MAINLY AFTER THE MORNING DRIVE...AND THEN
LEAVING UP TO AN INCH OF ACCUMULATION BEFORE ENDING BY MIDNIGHT
WEDNESDAY NIGHT. EXPECT THIS TO BE MOSTLY A MID LEVEL ISENTROPIC
LIFT DRIVEN EVENT AS MODEL DEPICTIONS OF THE 500 MB HEIGHT FIELD
SHOW CONSOLIDATION OF SHORT WAVES IN THE FLOW BUT WITH FRAGMENTED
DYNAMIC SUPPORT IN TERMS OF DCVA. THE LOW LEVEL FRONTAL ZONE IS ALSO
LOCATED WELL SOUTH INTO THE OHIO AND TENNESSEE VALLEYS JUDGING BY
1000-850 MB THICKNESS. THIS DOES NOT PREVENT ADEQUATE MOISTURE FROM
REACHING THIS FAR NORTH AS SPECIFIC HUMIDITY AVERAGES 1-2 G/KG UP TO
700 MB OVER LOWER MICHIGAN. IT DOES INDICATE THE SHALLOW AND STABLE
NATURE OF THE SYSTEM RELATIVE ISENTROPIC LIFT. AS MENTIONED IN THE
PREVIOUS DISCUSSION...MODEL SOUNDINGS DO INDICATE A DEEP ISOTHERMAL
PROFILE WITHIN THE DGZ BELOW 600 MB WHICH WILL GIVE A BOOST TO SNOW
RATIO AND POTENTIAL OVERACHIEVEMENT. THE COLLABORATED QPF ADJUSTMENTS
MADE IN THE PREVIOUS FORECAST CYCLE ARE THUS PRESERVED FOR THIS
PACKAGE.
EXTENDED THURSDAY THROUGH TUESDAY... AS WEDNESDAY`S WAVE OF LOW
PRESSURE EXITS THE REGION...A SLIGHT CHANCE OF SNOW SHOWERS WILL
REMAIN IN THE FORECAST THROUGH EARLY THURSDAY MORNING. BRIEF HIGH
PRESSURE BUILDS OVER THE AREA DURING THE DAY ON THURSDAY. THIS
HIGH PRESSURE IS EXPECTED TO PRODUCE A DECENT DRY DAY WITH MOSTLY
TO PARTLY CLOUDY SKIES OVER THE WHOLE OF SOUTHEAST MICHIGAN. AN
UPPER LEVEL TROUGH SWINGS ACROSS THE NORTHERN THUMB AREAS ON
FRIDAY...GENERATING ANOTHER WEAK SHOT AT SNOW SHOWERS. HIGH
PRESSURE IS ON TAP TO RETURN FOR THE WEEKEND. TEMPERATURE
CONTINUES TO WARM THROUGH THE PERIOD WITH HIGHS EDGING INTO THE
MID 30`S BY SUNDAY OVER SOUTHERN HALF OF THE CWA.
MARINE...
A SURFACE TROUGH SLOWLY DROPPING THROUGH LAKE HURON WILL MAINTAIN
STRONG WESTERLY WINDS THROUGH THE REMAINDER OF THE AFTERNOON AND
EVENING OVER SOUTHERN LAKE HURON...LAKE ST CLAIR...AND WESTERN LAKE
ERIE. WINDS WILL BE STRONGEST OVER THE SOUTHERN THIRD OF LAKE
HURON...WHERE GUSTS WILL PRIMARILY REMAIN AROUND 30 KNOTS...BUT A
FEW GUSTS TO GALE FORCE ARE POSSIBLE. SMALL CRAFT ADVISORIES REMAIN
IN EFFECT FOR THE NEARSHORE WATERS OF LAKE HURON FROM OUTER SAGINAW
BAY DOWN TO PORT HURON. THE REMAINDER OF THE NEARSHORE WATERS ARE
ICE COVERED AND THEREFORE REMAIN WITHOUT A HEADLINE. WINDS WILL
DECREASE EARLY TONIGHT AS THE SURFACE TROUGH DROPS SOUTHWARD.
IN ADDITION...THE STRONG WINDS AND ARCTIC AIRMASS IN PLACE WILL
CREATE FAVORABLE CONDITIONS FOR FREEZING SPRAY TO DEVELOP OVER LAKE
HURON THROUGH TUESDAY...ESPECIALLY ACROSS THE OPEN WATERS. INTENSITY
LOOKS TO ONLY REMAIN MODERATE HOWEVER.
WINDS WILL REMAIN A LITTLE GUSTY OUT OF THE NORTHWEST ACROSS LAKE
HURON TUESDAY BEFORE HIGH PRESSURE BUILDING INTO THE CENTRAL GREAT
LAKES AND OHIO VALLEY BRINGS LIGHTER WIND CONDITIONS FROM LATE
TUESDAY INTO WEDNESDAY.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&
$$
AVIATION.....CB
UPDATE.......CB
DISCUSSION...BT/DE
MARINE.......HLO
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1131 PM EST MON JAN 18 2016
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 410 PM EST MON JAN 18 2016
WV IMAGERY AND RAP ANALYSIS INDICATED A MID/UPPER LEVEL LOW FROM THE
ERN LAKES INTO NRN NEW ENGLAND WITH A SHORTWAVE TROUGH EXTENDING NW
TO NEAR LAKE SUPERIOR. AT THE SFC...A LAKES AGGREGATE TROUGH EXTENDED
FROM LAKE HURON INTO SRN LAKE SUPERIOR. MULTIPLE WIND PARALLEL LES
BANDS WITH NW ARCTIC FLOW CONTINUED. 850 MB TEMPS AROUND -23C
PROVIDED PLENTIFUL INSTABILITY WITH LAKE INDUCED CAPES INTO THE
500-750 J/KG. THE MID LEVEL SHRTWV AND ASSOCIATED 700-300 MB QVECTOR
CONV HAS ALSO HELPED BOOST INVERSION/EQUILIBRIUM HEIGHTS THIS
AFTERNOON. VIS LOOP...SFC OBS AND WEB CAMS SUGGEST THE HEAVIER LES
WAS OVER THE ERN CWA...IN CLOSER PROXIMITY TO THE SHRTWV AND
DOWNSTREAM FROM THE LONGEST FETCH.
TONIGHT...THE HIGH RES MODELS SUGGEST THAT LOW LEVEL WINDS WILL VEER
SLIGHTLY IN THE WAKE OF THE SHRTWV...HELPING TO PUSH THE MORE
PROMINENT LES BANDS INTO CNTRL AND WRN ALGER COUNTY. WITH ADDITIONAL
SNOWFALL AMOUNTS IN THE 3 TO 7 INCH RANGE EXPECTED...THE LES WARNING
WAS EXTENDED (TIL 12Z) FOR ALGER AND NRN SCHOOLCRAFT COUNTIES WITH
AN THE ADVY INTO SRN SCHOOLCRAFT ALSO EXTENDED TIL 06Z.
OVER THE WEST...INVERSION HEIGHTS DROP OFF TO AROUND 4K FT THIS
EVENING WHICH SHOULD LIMIT LES INTENSITY WITH ADDITIONAL SNOWFALL
AMOUNTS TO ADVY AMOUNTS IN THE 2 TO 5 INCH RANGE OR LESS. THE
STRONGER LOW LEVEL CONV FROM ONTONAGON EASTWARD SHOULD ALSO SAG TO
THE SOUTH THIS EVENING.
TUE...LES SHOULD CONTINUE TO DIMINISH WITH INVERSION HEIGHTS FALLING
TO 3K-4K FT AND WINDS BACKING ACYC WRLY AS A SFC RIDGE BUILDS FROM
THE UPPER MS VALLEY INTO THE WRN LAKES. TEMPS WILL ALSO MODERATE
WITH HIGHS FROM THE LOWER TEENS WEST TO AROUND 20 EAST.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 324 PM EST MON JAN 18 2016
THE 500MB RIDGE OVERHEAD ON TUESDAY WILL SLOWLY EXIT E TUESDAY NIGHT
AND WEDNESDAY IN RESPONSE TO THE ELONGATED TROUGH EXTENDING FROM S
CENTRAL CANADA THROUGH W MN AND IA AT 00Z WEDNESDAY. THIS TROUGH
WILL SLIDE ACROSS THE UPPER GREAT LAKES DURING THE DAY
WEDNESDAY...AND TO THE LOWER GREAT LAKES 00-06Z THURSDAY. THIS WILL
BY WHILE THE LARGE SFC HIGH STRETCHING FROM THE UPPER GREAT LAKES TO
THE TIP OF FL AT 00Z WEDNESDAY SLOWLY BECOMES SUPRESSED TO THE SE. LOOKING
SPECIFICALLY AT THE LINGERING LAKE INDUCED TROUGH OVER LAKE
SUPERIOR...IT WILL SLOWLY DEEPEN OVERNIGHT AND INTO THURSDAY. EXPECT
LINGERING LES BANDS TO SHIFT ACROSS THE TIP OF THE KEWEENAW
PENINSULA AND FAR N LUCE COUNTY...AND EVENTUALLY OFFSHORE AS
SFC WINDS SHIFT TO A MORE S-SW DIRECTION.
A SHORTWAVE PUSHING ACROSS THE PACIFIC NORTHWEST WEDNESDAY MORNING
WILL LIVE ACROSS THE PLAINS STATES WEDNESDAY NIGHT WHILE A N WAVE
MOVES ACROSS LAKE SUPERIOR/UPPER MI. BY 00Z THURSDAY THE SFC MAP
WILL SHOW THE NEXT LOW OVER FAR E CO WILL HAVE AN INVERTED TROUGH UP
THROUGH SW MN AND W ONTARIO. THE N LOW WILL BE FAIRLY
PROGRESSIVE...MOVING OVER LAKE SUPERIOR BY 12Z THURSDAY AND EXITING
ACROSS LOWER MI THURSDAY NIGHT...MERGING WITH THE STRONGER LOW
ACROSS TN. THIS WILL BRING THE BEST CHANCE OF WIDESPREAD SNOW FOR
THIS LONG TERM PERIOD...WILL LIKELY BE LATE THURSDAY INTO EARLY
FRIDAY. AT THIS POINT THE GFS IS THE MOST ROBUST WITH THE SNOW WITH
1-4IN CWA WIDE. THE ON THE POSITIVE SIDE THE DGZ IS WITHIN THE
MOISTURE LAYER...BUT INVERSION HEIGHTS LOOK TO FALL PRETTY QUICKLY
OVERNIGHT THURSDAY NIGHT INTO FRIDAY MORNING. FAVORABLE UPSLOPE
CONDITIONS FOR LES DO NOT SEEM TO RETURN TO THE CWA UNTIL LATE
THURSDAY AFTERNOON IN THE FORM OF NW WIND BEHIND THE EXITING SFC
LOW. THEY WILL NOT BE ALL THAT STEADY FOR SIGNIFICANT DOMINANT BANDS
TO DEVELOP AS WINDS SHIFT OUT OF THE N-NNE BY DAYBREAK FRIDAY. A
GENERAL 500MB TROUGH WILL BE SETUP ACROSS THE UPPER GREAT LAKES
THROUGH THE GULF OF MEXICO W THURSDAY-FRIDAY...KEEPING COOLER AIR
OVER THE AREA. 850MB TEMPS WILL REMAIN -7 TO -14C.
LOOK FOR A SIGNIFICANT RIDGE OF HIGH PRESSURE AT 500MB FRIDAY NIGHT
TO EXTEND FROM THE INTERIOR SW UP THROUGH THE PLAINS TO PUSH INTO
THE UPPER GREAT LAKES AS THE S TROUGH DEEPENS TO A LOW AND BEGINS TO
EXIT OFF THE MID ATLANTIC SEABOARD. THIS 500MB LOW WILL PUSH N JUST
OFF THE NEW ENGLAND COAST BY SUNDAY MORNING. WAA WILL RESULT...AS
850MB TEMPS RISE TO -5 TO -10C BY 06Z SATURDAY /WARMEST OFF THE
ECMWF/...AND -1 TO -5C BY 00Z SUNDAY ON SW 850MB WINDS NEARING 35KTS.
THERE ARE SOME DIFFERENCES IN THE HANDLING OF THE 500MB LOW OVER N
CANADA FOR THE END OF THE UPCOMING WEEKEND. WHILE BOTH THE GFS AND
ECMWF SHOW A DEEP TROUGH SWINGING ACROSS MUCH OF THE NATION...THE
GFS IS FARTHER S WITH THIS FEATURE. EXPECT SOME STEADY SNOW TO SLIDE
IN FROM THE S SUNDAY EVENING INTO EARLY MONDAY...BUT TIMING AND
INTENSITY COULD CHANGE SIGNIFICANTLY BETWEEN NOW AND THEN.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1131 PM EST MON JAN 18 2016
AT KIWD...EXPECT IFR VSBY/CISG DURING THE HEAVIER SNOW BANDS AT IWD
EARLY IN THIS FORECAST...BUT THEN WINDS BACKING LATE TONIGHT WILL
ALLOW FOR IMPROVEMENT TO MVFR IN LIGHTER LAKE EFFECT SHOWERS. EXPECT
A RETURN TO VFR CONDITIONS TUE AFTERNOON AS WINDS BACK TO THE SW.
AT KCMX...CONTINUED LAKE EFFECT SNOW SHOWERS WILL STILL RESULT IN
PREVAILING IFR/LOW MVFR CONDITIONS THROUGH TUE AFTERNOON BEFORE
MVFR CONDITIONS RETURN BY TUE NIGHT.
AT KSAW...EXPECT MVFR EARLY THIS MORNING AS WINDS VEER FROM NW TO
NNW AND SOME LIGHT LAKE EFFECT SNOW BRUSHES THE AREA. BACKING WINDS
LATE TONIGHT WILL ALLOW IMPROVEMENT AGAIN TO VFR.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 410 PM EST MON JAN 18 2016
EXPECT WINDS TO DIMINISH LATER THIS EVENING TO 20-25 KTS...HIGHEST
OVER ERN LAKE SUPERIOR. IN ADDITION...HEAVY FREEZING SPRAY IS
EXPECTED WILL ALSO END EARLY THIS EVENING. WINDS ARE EXPECTED TO
SLOWLY DIMINISH TOWARDS THE MIDDLE OF THE WEEK...AS HIGH PRESSURE
MOVES OVER THE UPPER GREAT LAKES REGION.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW WARNING UNTIL 7 AM EST TUESDAY FOR MIZ006-085.
LAKE EFFECT SNOW ADVISORY UNTIL 1 AM EST TUESDAY FOR MIZ014.
LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST TUESDAY FOR MIZ001>003-
084.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KF
AVIATION...07
MARINE...JLB
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
924 PM CST WED JAN 20 2016
.UPDATE:
Issued at 859 PM CST Wed Jan 20 2016
Mid-high level cloudiness will continue to spread eastward
through our forecast area ahead of a strong shortwave moving
slowly eastward through KS. There may also be some stratus clouds
developing or retrograding from IL into parts of the area. The
radar was depicting some light precipitation in eastern KS ahead
of the shortwave. Looking at the latest HRRR and NAM model runs it
appears that this precipitation will remain west of our forecast
area tonight. With the cloud cover and lowering cloud ceilings
expected the temperatures later tonight should be nearly steady or
even rise slightly.
GKS
&&
.SHORT TERM: (Through Late Tonight)
Issued at 330 PM CST Wed Jan 20 2016
Morning stratus has developed several holes in it during the course
of the day and now only occupies areas in southern IL and northeast
MO. Temps are in the upper 20s and lower 30s where the sun has
broken out of the clouds, while still in the lower to mid 20s
elsewhere. Another storm system has taken shape over western and
central KS with an area of snow, while a much more significant
system is moving thru UT and western CO at this time.
The system over KS is expected to move slowly east tonight and
weaken with time, only making it to the eastern part of the state by
12z/Thu. Any pcpn associated with this system should remain to the
west of our region tonight. Of more significant note and challenge
will be sky cover, its effects on temps, and potential for any fog.
Sky cover should come from two main sources tonight: first from mid
and hi clouds that will overspread our region later this evening
from the KS system, and also from the low stratus that survives
(mainly in southern IL) that will take advantage of veering cloud
level winds from north to southeast to both advect westward into the
heart of our region and expand in coverage as it does so.
Ultimately, this will cloud up all areas again, but not before many
areas will have the opportunity to have several hours of mostly
clear skies with light easterly winds this evening with fresh snow
cover. Have tried to compensate for this contingency in the min
temp forecast, allowing for some areas in IL especially to drop into
the single digits, and this will probably also allow for some fog
development. As clouds increase later tonight, should see temps
either steady out or even rise a few degrees. Biggest adjustments
to MOS min temps are to the north and northeast of STL.
TES
.LONG TERM: (Thursday through Next Wednesday)
Issued at 330 PM CST Wed Jan 20 2016
Focus continues to be system on Thurs into Fri.
Latest mdl guidance has continued a more sly track. Mdls do continue
to track a leading s/w lifting newd into the region late tonight
into Thurs. Can not completely rule out light precip across portions
of central MO, but based on forecast soundings, any precip will be
light and sct. Of some concern is that while the NAM is the only mdl
to suggest precip across this area, soundings also suggest that the
available moisture may not be deep enuf for SN and FZDZ may be a
threat.
Otherwise, PoPs have been removed thru the weekend. Will need to
continue to monitor the more nrn trof Thurs night into Fri as it
drops swd into the area. Mdls suggest that any available moisture
will precip out before it reaches the CWA. Regardless, will need to
continue to monitor.
Focus then turns to a system on Mon into Tues with a more amplified
trof digging into the region. Mdls disagree regarding how this
system will evolve and have therefore kept PoPs on the low end. Have
also kept a RA vs. SN going for now. Will begin to fine tune p-types
as the system approaches and mdls come into better agreement.
Tilly
&&
.AVIATION: (For the 00z TAFs through 00z Thursday Evening)
Issued at 536 PM CST Wed Jan 20 2016
VFR flight conditions prevail across the region at this time,
however MVFR cigs are not far removed and that is the forecast
issue for this TAF package. Stratus with cig heights from
1500-2000 ft stretched from the OH Valley into far southern IL and
was also located across south central MO. Current expectations are
that the flow in the lowest 3kft of the atmosphere will gradually
veer to more southeasterly this evening, and this should allow the
stratus to advect northwest. If this in fact occurs the St. Louis
region terminals and KCOU will be impacted and that is reflected
in the latest TAFs, with cigs lowering to IFR on Thursday morning
at KCOU. Will also have to be on the watch for some light snow in
central MO but the probability is currently too low to mention. Some
improvement expected by midday and into the afternoon on Thursday
as the low level flow veers to more northeasterly.
Specifics for KSTL:
VFR flight conditions prevail across the region at this time,
however MVFR cigs are not far removed as stratus with cig heights
from 1500-2000 ft stretched from the OH Valley into far southern
IL. Current expectations are that the flow in the lowest 3kft of
the atmosphere will gradually veer to more southeasterly this
evening, and this should allow the stratus to advect northwest and
back into the terminal. Improvement expected by midday and into
the afternoon on Thursday as the low level flow veers to more
northeasterly.
Glass
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1207 PM CST TUE JAN 19 2016
.UPDATE:
Issued at 1021 AM CST Tue Jan 19 2016
Have got reports of light snow in Mexico and Columbia ahead of
the main band of snow farther west where visibilities have been
reduced to around 1 mile. Still expect this band to move slowly
east today as there will be some sublimation by dry air in the
lower atmosphere. Latest runs of the RAP and HRRR does show a
sharp increase ascent ahead of the mid level trough later this
afternoon and this evening which should increase the coverage of
snow coverage over the area. Low-mid level moisture convergence will
increase ahead of this trough late this afternoon into the evening
along and south of I-70 which will aid in the production of snow
and some sleet.
The precipitation falling into the dry air and the clouds should
keep temperatures from rising too much today. Otherwise...going
forecast looks pretty much on track.
Britt
&&
.SHORT TERM: (Through Tonight)
Issued at 403 AM CST Tue Jan 19 2016
All is on track for the first really widespread accumulating
snowfall of at least a couple of inches across the CWA. Latest NWP
guidance continues the colder trend in the lower levels.
Consequently...confined the mention of sleet to a small portion of
southeastern Missouri. Where sleet does mix in with the snow...it
appears it would likely be fairly brief and not too greatly affect
snow totals down that way. Going with a colder profile...also bumped
snow-to-liquid ratios up a bit higher though did not want to get too
aggressive as strongest ascent should be well below DGZ which may
mix in columns with dendrites. If columns end up being favored over
dendrites for any length of time...forecast snow amounts would
likely be a bit too high However...models have also come in a touch
drier for most locations...particularly the northern 2/3 of the CWA.
Therefore...snow amounts across much of the area are very similar to
what the day shift had forecast with the notable exception of
portions of southeastern Missouri and southwestern Illinois. The
snow totals across these areas were boosted primarily due to the
colder profile.
Light snow is expected to transverse the area very late this morning
and into the afternoon within a band of 850-700 hPa frontogenesis.
Atmosphere is initially quite dry attm...but believe saturation at
mid/lower levels should occur across portions of north-central
Missouri southeastward toward the St. Louis metro area by mid
afternoon.
The main thrust of snowfall still appears to be from 0000 UTC to
09000 UTC tonight as the trough axis approaches from the west
coincident with very strong warm/moist advection on the nose of a 40-
kt LLJ. Models have begun to depict two precipitation maxima with
this event (or one minimum depending on how you look at it). One
precip/snowfall maximum from roughly KMYJ>K3LF due to the
combination of the aforementioned frontogenetically-driven band of
snow during the day today and strong DCPVA ahead of a northern vort
max. Another area of enhanced precipitaton is shown across portions
of southeastern Missouri and southwest Illinois where the strongest
low-level forcing will reside tonight. Conceptually...this seems
very plausible. All that being said...still looks like areas across
central and northeastern Missouri as well as west-central Illinois
are in line to get 3 to 4+ inches of snow. Further southeast...most
of the rest of the area is expected to receive near 3 inches of snow.
Gosselin
.LONG TERM: (Wednesday through Monday)
Issued at 403 AM CST Tue Jan 19 2016
A brief break is expected along with dry conditions on Wednesday.
Lowered high temperatures for most areas a couple of degrees due
to expected snow cover across CWA.
As alluded to by previous forecaster...system on Thursday/Thursday
night appears more interesting than 24 hours ago. Complex system
evolution expected as a lead shortwave comes toward the MO/KS border
late Wednesday night with a southern vort diving toward the Arklatex
region. Two distinct vorticity maxima appear to have a bit of the
Fujiwara effect with the northern vort rotating counter-clockwise
around the more dominant/stronger southern vort. Combination of weak
WAA and support aloft is expected to develop light snow during
the day on Thursday. Best chances south of I-70. Models diverge a
bit on track/strength of system but appears a deformation zone
will form on Thursday night and continue into Friday. Best chances
of snowfall with this feature would likely be across far southern
portions of the CWA. Still a lot of model spread for this
particular system and it bears watching. Taking a look at 16 GFS
ensemble members yielded 4 members much further north than
operational run with a few others quite a bit further south too.
Mostly dry weather is forecast for this weekend and next Monday
along with moderating temperatures back to near normal.
However...depending on exactly how much snow falls and where over
the next several days...these temperatures could be too warm or
too cold.
Gosselin
&&
.AVIATION: (For the 18z TAFs through 18z Wednesday Afternoon)
Issued at 1207 AM CST Tue Jan 19 2016
A band of snow is getting ready to move into KCOU and will continue
to move east toward KUIN and the St. Louis area terminals later
this afternoon. Snow is expected to continue into this evening and
will accumulate 3-4 inches at all of the terminals before ending
shortly between 06-12Z at the terminals once the system moves
east of the area. The snow will require the clearing of runways
and will reduce the visibilities to IFR at times. Even after the
snow ends, the ceilings may stay IFR for a time before they
improve to low MVFR.
Specifics for KSTL: Snow is expected to move into the terminal
from the west after 18Z. The snow will reduce visibilities to MVFR
or IFR at times as the snow begins to accumulate during the late
afternoon and evening hours. Total accumulations are expected to
be around 3 inches. Even after the snow ends, the ceilings may
stay IFR for a time before they improve to low MVFR. VFR ceilings
are expect after 18Z tomorrow when drier air moves into the area.
Britt
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...Winter Weather Advisory until 6 AM CST Wednesday FOR Audrain MO-
Boone MO-Callaway MO-Cole MO-Crawford MO-Franklin MO-
Gasconade MO-Jefferson MO-Knox MO-Lewis MO-Lincoln MO-
Marion MO-Moniteau MO-Monroe MO-Montgomery MO-Osage MO-Pike
MO-Ralls MO-Shelby MO-St. Charles MO-St. Louis City MO-St.
Louis MO-Warren MO-Washington MO.
Winter Weather Advisory from 6 PM this evening to 6 AM CST
Wednesday FOR Iron MO-Madison MO-Reynolds MO-St. Francois
MO-Ste. Genevieve MO.
IL...Winter Weather Advisory until 6 AM CST Wednesday FOR Adams IL-
Brown IL-Calhoun IL-Greene IL-Jersey IL-Madison IL-Monroe
IL-Pike IL-St. Clair IL.
Winter Weather Advisory from 6 PM this evening to 6 AM CST
Wednesday FOR Bond IL-Clinton IL-Fayette IL-Macoupin IL-
Marion IL-Montgomery IL-Randolph IL-Washington IL.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
1022 AM CST TUE JAN 19 2016
.UPDATE:
Issued at 1021 AM CST Tue Jan 19 2016
Have got reports of light snow in Mexico and Columbia ahead of
the main band of snow farther west where visibilites have been
reduced to around 1 mile. Still expect this band to move slowly
east today as there will be some sublimation by dry air in the
lower atmosphere. Latest runs of the RAP and HRRR does show a
sharp increase ascent ahead of the mid level trough later this
afternoon and this evening which should increase the coverage of
snow coverage over the area. Low-mid level moisture convergence will
increase ahead of this trough late this afternoon into the evening
along and south of I-70 which will aid in the production of snow
and some sleet.
The precipitation falling into the dry air and the clouds should
keep temperatures from rising too much today. Otherwise...going
forecast looks pretty much on track.
Britt
&&
.SHORT TERM: (Through Tonight)
Issued at 403 AM CST Tue Jan 19 2016
All is on track for the first really widespread accumulating
snowfall of at least a couple of inches across the CWA. Latest NWP
guidance continues the colder trend in the lower levels.
Consequently...confined the mention of sleet to a small portion of
southeastern Missouri. Where sleet does mix in with the snow...it
appears it would likely be fairly brief and not too greatly affect
snow totals down that way. Going with a colder profile...also bumped
snow-to-liquid ratios up a bit higher though did not want to get too
aggressive as strongest ascent should be well below DGZ which may
mix in columns with dendrites. If columns end up being favored over
dendrites for any length of time...forecast snow amounts would
likely be a bit too high However...models have also come in a touch
drier for most locations...particularly the northern 2/3 of the CWA.
Therefore...snow amounts across much of the area are very similar to
what the day shift had forecast with the notable exception of
portions of southeastern Missouri and southwestern Illinois. The
snow totals across these areas were boosted primarily due to the
colder profile.
Light snow is expected to transverse the area very late this morning
and into the afternoon within a band of 850-700 hPa frontogenesis.
Atmosphere is initially quite dry attm...but believe saturation at
mid/lower levels should occur across portions of north-central
Missouri southeastward toward the St. Louis metro area by mid
afternoon.
The main thrust of snowfall still appears to be from 0000 UTC to
09000 UTC tonight as the trough axis approaches from the west
coincident with very strong warm/moist advection on the nose of a 40-
kt LLJ. Models have begun to depict two precipitation maxima with
this event (or one minimum depending on how you look at it). One
precip/snowfall maximum from roughly KMYJ>K3LF due to the
combination of the aforementioned frontogenetically-driven band of
snow during the day today and strong DCPVA ahead of a northern vort
max. Another area of enhanced precipitaton is shown across portions
of southeastern Missouri and southwest Illinois where the strongest
low-level forcing will reside tonight. Conceptually...this seems
very plausible. All that being said...still looks like areas across
central and northeastern Missouri as well as west-central Illinois
are in line to get 3 to 4+ inches of snow. Further southeast...most
of the rest of the area is expected to receive near 3 inches of snow.
Gosselin
.LONG TERM: (Wednesday through Monday)
Issued at 403 AM CST Tue Jan 19 2016
A brief break is expected along with dry conditions on Wednesday.
Lowered high temperatures for most areas a couple of degrees due
to expected snow cover across CWA.
As alluded to by previous forecaster...system on Thursday/Thursday
night appears more interesting than 24 hours ago. Complex system
evolution expected as a lead shortwave comes toward the MO/KS border
late Wednesday night with a southern vort diving toward the Arklatex
region. Two distinct vorticity maxima appear to have a bit of the
Fujiwara effect with the northern vort rotating counter-clockwise
around the more dominant/stronger southern vort. Combination of weak
WAA and support aloft is expected to devlop light snow during the
day on Thursday. Best chances south of I-70. Models diverge a bit on
track/strength of system but appears a deformation zone will form on
Thursday night and continue into Friday. Best chances of snowfall
with this feature would likely be across far southern portions of
the CWA. Still a lot of model spread for this particular system and
it bears watching. Taking a look at 16 GFS ensemble members yielded
4 members much futher north than operational run with a few others
quite a bit further south too.
Mostly dry weather is forecast for this weekend and next Monday
along with moderating temperatures back to near normal.
However...depending on exatly how much snow falls and where over the
next several days...these temperatures could be too warm or too cold.
Gosselin
&&
.AVIATION: (For the 12z TAFs through 12z Wednesday Morning)
Issued at 550 AM CST Tue Jan 19 2016
Mid and high clouds moving in ahead of weather system this
morning. Will see snow develop and spread east across the area
after 17z with cigs and vsbys lowering to MVFR with onset, then
dip down to IFR with the heavier bands of snow by this afternoon
through this evening. Snow to taper off from west to east after
05z Wednesday. Otherwise, winds to persist from the east through
the forecast period.
Specifics for KSTL:
Mid and high clouds moving in ahead of weather system this
morning. Will see snow develop and spread into the STL metro area
by 21z with cigs and vsbys lowering to MVFR with onset, then dip
down to IFR with the heavier bands of snow by 00z Wednesday. Snow
to taper off after 07z Wednesday. Otherwise, winds to persist
from the east through the forecast period.
Byrd
&&
.PRELIMINARY POINT TEMPS/POPS:
Saint Louis 23 20 29 23 / 70 100 10 5
Quincy 20 16 26 20 / 80 90 10 5
Columbia 23 20 32 23 / 90 90 5 10
Jefferson City 25 21 32 24 / 90 90 5 10
Salem 22 20 27 22 / 20 100 40 5
Farmington 25 22 31 23 / 40 90 20 10
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...Winter Weather Advisory until 6 AM CST Wednesday FOR Audrain MO-
Boone MO-Callaway MO-Cole MO-Crawford MO-Franklin MO-
Gasconade MO-Jefferson MO-Knox MO-Lewis MO-Lincoln MO-
Marion MO-Moniteau MO-Monroe MO-Montgomery MO-Osage MO-Pike
MO-Ralls MO-Shelby MO-St. Charles MO-St. Louis City MO-St.
Louis MO-Warren MO-Washington MO.
Winter Weather Advisory from 6 PM this evening to 6 AM CST
Wednesday FOR Iron MO-Madison MO-Reynolds MO-St. Francois
MO-Ste. Genevieve MO.
IL...Winter Weather Advisory until 6 AM CST Wednesday FOR Adams IL-
Brown IL-Calhoun IL-Greene IL-Jersey IL-Madison IL-Monroe
IL-Pike IL-St. Clair IL.
Winter Weather Advisory from 6 PM this evening to 6 AM CST
Wednesday FOR Bond IL-Clinton IL-Fayette IL-Macoupin IL-
Marion IL-Montgomery IL-Randolph IL-Washington IL.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS HASTINGS NE
653 PM CST WED JAN 20 2016
.UPDATE...
ISSUED AT 653 PM CST WED JAN 20 2016
BASED ON CURRENT TRENDS AND REPORTS AND THE LATEST HIGH-RES
GUIDANCE HAVE INCREASED SNOW AMOUNTS FOR PORTIONS OF THE
AREA...MAINLY FRANKLIN COUNTY NEBRASKA AND PHILLIPS AND ROOKS
COUNTIES IN KANSAS. EXPECT BETWEEN 2 AND 4 INCHES IN THOSE
LOCATIONS AND HAVE EXPANDED THE WINTER WEATHER ADVISORY TO INCLUDE
THESE COUNTIES. WILL CONTINUE TO UPDATE AS NECESSARY.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 356 PM CST WED JAN 20 2016
BIGGEST FORECAST ISSUE WILL BE SNOW AMOUNTS FOR TONIGHT.
SNOW HAS BEGUN A BIT EARLIER THAN ANTICIPATED IN OUR SOUTH IN
ADVANCE OF THE LONG-AWAITED APPROACHING WAVE WITHIN PROGRESSIVE
FLOW. BACKED UP THE START TIME OF THE ADVISORY FOR OUR KANSAS
COUNTIES TO INCLUDE THIS AFTERNOON. ALSO INCREASED SNOW AMOUNTS A
BIT IN OUR SOUTH...WHICH REQUIRED THE ADDITION OF A FEW COUNTIES ON
THE WESTERN EDGE OF THE WINTER WEATHER ADVISORY...TO INCLUDE
WEBSTER...SMITH...AND OSBORNE COUNTIES. EXPECTING A RATHER TYPICAL
13:1 RATIO FOR LIQUID TO SNOW.
FORECAST IS LARGELY ON TRACK FROM THE PREVIOUS FORECAST TONIGHT WITH
MINOR CHANGES MADE IN GENERAL. SNOWFALL MAY NOT FOLLOW A SMOOTH
TRANSITION FROM HEAVIER TO LIGHTER AMOUNTS FROM SOUTH TO NORTH...AS
WE COULD GET A FEW CONVECTIVE BANDS TO MOVE THROUGH...AS INDICATED
BY SHORT TERM MODELS SUCH AS HRRR AND RAP.
ANOTHER ISSUE MAY COME LATE THURSDAY AFTERNOON WHEN WE COULD LOSE
SATURATION IN THE DENDRITIC GROWTH ZONE BEFORE ALL OF THE LIGHT
LINGERING PRECIPITATION EXITS. IF THIS OCCURS...THEN WE COULD GET
SOME FREEZING DRIZZLE DEVELOP LATE AFTERNOON THURSDAY.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 356 PM CST WED JAN 20 2016
HAZARDOUS WX POTENTIAL: NOTHING SIGNIFICANT FORESEEN AT THIS TIME.
ALOFT: SOME TEMPORARY PROGRESSION OF THE LONGWAVES WILL OCCUR AS THE
PERSISTENT E PAC TROF MOVES ONSHORE SAT AND INTO THE CNTRL USA SUN-
MON. THIS TROF WILL SHIFT INTO THE ERN USA BEYOND MON. THEN IT`S
BACK TO THE PATTERN DOMINATING THE PAST 2 WEEKS...WITH THE E PAC
TROF/WRN N AMERICA RIDGE REDEVELOPING.
SURFACE: CANADIAN HIGH PRES WILL CREST OVER THE FCST AREA THU NIGHT
INTO FRI. SAT THE FCST AREA WILL BE IN THE WARM SECTOR OF A CLIPPER
TRACKING ACROSS SRN CANADA. LEE CYCLOGENESIS WILL ENSUE SAT NIGHT
WITH THE APPROACH OF THE UPR TROF. A PAC COLD FRONT WILL SLIP THRU
SUN AS THIS LOW CONTS TO ORGANIZE OVER OK/KS. WPC HAS THIS LOW OVER
CNTRL MO AT 12Z/MON WHICH IS CLOSE TO THE 06Z/12Z GFS AND THE
00Z/12Z GEM. INTERESTINGLY...THE 12Z GFS ENSEMBLE MEAN IS ON THE
SLOW END OF THE GUIDANCE SPREAD (OVER ERN KS/OK) WHILE THE 00Z/12Z
EC AND THE 00Z ENSEMBLE MEAN ARE ON THE FASTER END OVER IA.
HIGH PRES OVERTAKES THE REGION MON AND SINKS INTO THE SRN PLAINS TUE-
WED. DOWNSLOPE-WARMED AIR SHOULD FLOOD THE PLAINS AS A COUPLE
CLIPPERS TRACK N OF THE FCST AREA.
SOME DAILY DETAILS...
THU NIGHT: A LITTLE LIGHT SNOW OR FRZG DRZL COULD LINGER INTO THE
EVENING HRS MAINLY HWY 81. CONFIDENCE IS LOW. OTHERWISE CLOUDY. KEPT
LOW TEMPS A LITTLE ABOVE NORMAL.
FRI: LOTS OF UNCERTAINTY ON DEPARTURE OF THE LOW CLOUDS...BUT THE
THERMAL TROF SHIFTING E IS A GOOD SIGN. HIGH TEMPS ARE LOW
CONFIDENCE. THE SNOW THAT FALLS TONIGHT WILL BE A PLAYER.
SAT: INCREASING/DESCENDING MULTI-LAYERED CLOUDS...ESPECIALLY IN THE
AFTERNOON. IT`S LOOKING VERY MILD...BUT AGAIN SNOW COVER A
MITIGATING FACTOR.
SUN: THE FCST IS CURRENTLY DRY...BUT IT`S POSSIBLE SOME LIGHT PRECIP
COULD BREAK OUT IN THE AFTERNOON. NOT EXACTLY SURE ON PRECIP TYPE AS
WETBULB COOLING COULD BE AN ISSUE IN THE INITIALLY DRY AIR BELOW 10K
FT.
THE LAST 2 RUNS OF THE OP MODELS ARE ALL OVER THE PLACE WITH VERY
LIGHT QPF AND AMTS SUN NIGHT. THE 12Z GFS ENSEMBLE DOES HAVE A 30%
PROBABILITY FOR .10" IN 24 HRS OVER S-CNTRL NEB. THE 12Z EC ENSEMBLE
IS SIMILAR. SO THERE COULD BE A TOUCH OF LIGHT WINTRY PRECIP.
MON: A LITTLE LIGHT SNOW COULD LINGER INTO THE MORNING. COLD SECTOR
WITH THERMAL TROF PASSING THRU. COLDER AND PROBABLY M/CLOUDY.
THE-WED: DRY AND QUIET WITH TEMPS MODERATING.
&&
.AVIATION...(FOR THE 00Z KGRI/KEAR TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 554 PM CST WED JAN 20 2016
THE MAIN AVIATION FORECAST CONCERN IS SNOW WHICH WILL CAUSE LOW
CEILINGS AND VISIBILITIES. IFR TO LIFR CONDITIONS WILL BE LIKELY
AT LEAST OFF AND ON THROUGH THE OVERNIGHT HOURS. SNOW IS EXPECTED
TO PREVAIL OVERNIGHT AND BECOME LIGHTER DURING THE MORNING HOURS
WHICH WILL ALLOW VISIBILITIES TO IMPROVE...BUT CEILINGS WILL
STRUGGLE REMAINING IN IFR TO LOW END MVFR.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...WINTER WEATHER ADVISORY UNTIL NOON CST THURSDAY FOR NEZ084>087.
KS...WINTER WEATHER ADVISORY UNTIL NOON CST THURSDAY FOR KSZ005>007-
017>019.
&&
$$
UPDATE...BILLINGS WRIGHT
SHORT TERM...HEINLEIN
LONG TERM...HALBLAUB
AVIATION...BILLINGS WRIGHT
AREA FORECAST DISCUSSION
NWS HASTINGS NE
554 PM CST WED JAN 20 2016
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 356 PM CST WED JAN 20 2016
BIGGEST FORECAST ISSUE WILL BE SNOW AMOUNTS FOR TONIGHT.
SNOW HAS BEGUN A BIT EARLIER THAN ANTICIPATED IN OUR SOUTH IN
ADVANCE OF THE LONG-AWAITED APPROACHING WAVE WITHIN PROGRESSIVE
FLOW. BACKED UP THE START TIME OF THE ADVISORY FOR OUR KANSAS
COUNTIES TO INCLUDE THIS AFTERNOON. ALSO INCREASED SNOW AMOUNTS A
BIT IN OUR SOUTH...WHICH REQUIRED THE ADDITION OF A FEW COUNTIES ON
THE WESTERN EDGE OF THE WINTER WEATHER ADVISORY...TO INCLUDE
WEBSTER...SMITH...AND OSBORNE COUNTIES. EXPECTING A RATHER TYPICAL
13:1 RATIO FOR LIQUID TO SNOW.
FORECAST IS LARGELY ON TRACK FROM THE PREVIOUS FORECAST TONIGHT WITH
MINOR CHANGES MADE IN GENERAL. SNOWFALL MAY NOT FOLLOW A SMOOTH
TRANSITION FROM HEAVIER TO LIGHTER AMOUNTS FROM SOUTH TO NORTH...AS
WE COULD GET A FEW CONVECTIVE BANDS TO MOVE THROUGH...AS INDICATED
BY SHORT TERM MODELS SUCH AS HRRR AND RAP.
ANOTHER ISSUE MAY COME LATE THURSDAY AFTERNOON WHEN WE COULD LOSE
SATURATION IN THE DENDRITIC GROWTH ZONE BEFORE ALL OF THE LIGHT
LINGERING PRECIPITATION EXITS. IF THIS OCCURS...THEN WE COULD GET
SOME FREEZING DRIZZLE DEVELOP LATE AFTERNOON THURSDAY.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 356 PM CST WED JAN 20 2016
HAZARDOUS WX POTENTIAL: NOTHING SIGNIFICANT FORESEEN AT THIS TIME.
ALOFT: SOME TEMPORARY PROGRESSION OF THE LONGWAVES WILL OCCUR AS THE
PERSISTENT E PAC TROF MOVES ONSHORE SAT AND INTO THE CNTRL USA SUN-
MON. THIS TROF WILL SHIFT INTO THE ERN USA BEYOND MON. THEN IT`S
BACK TO THE PATTERN DOMINATING THE PAST 2 WEEKS...WITH THE E PAC
TROF/WRN N AMERICA RIDGE REDEVELOPING.
SURFACE: CANADIAN HIGH PRES WILL CREST OVER THE FCST AREA THU NIGHT
INTO FRI. SAT THE FCST AREA WILL BE IN THE WARM SECTOR OF A CLIPPER
TRACKING ACROSS SRN CANADA. LEE CYCLOGENESIS WILL ENSUE SAT NIGHT
WITH THE APPROACH OF THE UPR TROF. A PAC COLD FRONT WILL SLIP THRU
SUN AS THIS LOW CONTS TO ORGANIZE OVER OK/KS. WPC HAS THIS LOW OVER
CNTRL MO AT 12Z/MON WHICH IS CLOSE TO THE 06Z/12Z GFS AND THE
00Z/12Z GEM. INTERESTINGLY...THE 12Z GFS ENSEMBLE MEAN IS ON THE
SLOW END OF THE GUIDANCE SPREAD (OVER ERN KS/OK) WHILE THE 00Z/12Z
EC AND THE 00Z ENSEMBLE MEAN ARE ON THE FASTER END OVER IA.
HIGH PRES OVERTAKES THE REGION MON AND SINKS INTO THE SRN PLAINS TUE-
WED. DOWNSLOPE-WARMED AIR SHOULD FLOOD THE PLAINS AS A COUPLE
CLIPPERS TRACK N OF THE FCST AREA.
SOME DAILY DETAILS...
THU NIGHT: A LITTLE LIGHT SNOW OR FRZG DRZL COULD LINGER INTO THE
EVENING HRS MAINLY HWY 81. CONFIDENCE IS LOW. OTHERWISE CLOUDY. KEPT
LOW TEMPS A LITTLE ABOVE NORMAL.
FRI: LOTS OF UNCERTAINTY ON DEPARTURE OF THE LOW CLOUDS...BUT THE
THERMAL TROF SHIFTING E IS A GOOD SIGN. HIGH TEMPS ARE LOW
CONFIDENCE. THE SNOW THAT FALLS TONIGHT WILL BE A PLAYER.
SAT: INCREASING/DESCENDING MULTI-LAYERED CLOUDS...ESPECIALLY IN THE
AFTERNOON. IT`S LOOKING VERY MILD...BUT AGAIN SNOW COVER A
MITIGATING FACTOR.
SUN: THE FCST IS CURRENTLY DRY...BUT IT`S POSSIBLE SOME LIGHT PRECIP
COULD BREAK OUT IN THE AFTERNOON. NOT EXACTLY SURE ON PRECIP TYPE AS
WETBULB COOLING COULD BE AN ISSUE IN THE INITIALLY DRY AIR BELOW 10K
FT.
THE LAST 2 RUNS OF THE OP MODELS ARE ALL OVER THE PLACE WITH VERY
LIGHT QPF AND AMTS SUN NIGHT. THE 12Z GFS ENSEMBLE DOES HAVE A 30%
PROBABILITY FOR .10" IN 24 HRS OVER S-CNTRL NEB. THE 12Z EC ENSEMBLE
IS SIMILAR. SO THERE COULD BE A TOUCH OF LIGHT WINTRY PRECIP.
MON: A LITTLE LIGHT SNOW COULD LINGER INTO THE MORNING. COLD SECTOR
WITH THERMAL TROF PASSING THRU. COLDER AND PROBABLY M/CLOUDY.
THE-WED: DRY AND QUIET WITH TEMPS MODERATING.
&&
.AVIATION...(FOR THE 00Z KGRI/KEAR TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 554 PM CST WED JAN 20 2016
THE MAIN AVIATION FORECAST CONCERN IS SNOW WHICH WILL CAUSE LOW
CEILINGS AND VISIBILITIES. IFR TO LIFR CONDITIONS WILL BE LIKELY
AT LEAST OFF AND ON THROUGH THE OVERNIGHT HOURS. SNOW IS EXPECTED
TO PREVAIL OVERNIGHT AND BECOME LIGHTER DURING THE MORNING HOURS
WHICH WILL ALLOW VISIBILITIES TO IMPROVE...BUT CEILINGS WILL
STRUGGLE REMAINING IN IFR TO LOW END MVFR.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...WINTER WEATHER ADVISORY UNTIL NOON CST THURSDAY FOR NEZ085>087.
KS...WINTER WEATHER ADVISORY UNTIL NOON CST THURSDAY FOR KSZ006-007-
018-019.
&&
$$
SHORT TERM...HEINLEIN
LONG TERM...HALBLAUB
AVIATION...BILLINGS WRIGHT
AREA FORECAST DISCUSSION
NWS HASTINGS NE
338 PM CST TUE JAN 19 2016
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 336 PM CST TUE JAN 19 2016
MAIN CONCERN IS FOG POTENTIAL TONIGHT. GENERAL SYNOPTIC PATTERN IS
QUITE PROGRESSIVE AS WE TRANSITION TO A HIGHER AMPLITUDE SCENARIO.
TONIGHT...THE CONCERN GOES TO FOG POTENTIAL TONIGHT AS WIND WILL BE
LIGHT FROM THE SOUTH. THE HRRR IS HITTING THE FOG POTENTIAL A LITTLE
HARD CENTRAL AND WEST. THE SREF IS ALSO HITTING FOG A LITTLE HARD
EVERYWHERE ACROSS THE CWA...ESPECIALLY WEST. I WENT WITH STRONG
WORDING IN THE FORECAST TO AREAS RATHER THAN PATCHY AND EXTENDED THE
FOG MENTION FARTHER EAST THAN THE PREVIOUS FORECAST.
WE MAY SEE A LITTLE SUN WEDNESDAY MORNING BEFORE IT CLOUDS BACK UP
IN ADVANCE OF THE NEXT WAVE QUICKLY APPROACHING. WARM AIR ADVECTION
SHOULD BOOST TEMPERATURES A GOOD 10 DEGREES WARMER ON WEDNESDAY
COMPARED TO TODAY. NOT EXPECTING PRECIP UNTIL PERHAPS BETWEEN 21Z
AND 00Z THURSDAY IN OUR FAR SOUTH...WHERE RAIN/SNOW COULD
OCCUR...BUT THE BETTER CHANCES WILL LIKELY BE TOWARD WEDNESDAY
NIGHT...IN THE LONG TERM FORECAST.
SUPERBLEND TEMPERATURES LOOKED REASONABLE...WHICH LOWERED
TEMPERATURES A BIT FOR WEDNESDAY HIGHS COMPARED TO THE PREVIOUS
FORECAST. THIS SEEMS REASONABLE CONSIDERING LINGERING FOG POTENTIAL
AND INCREASING SKY COVER BY AFTERNOON. BCONSRAW AND NAM12 SOLUTIONS
INDICATE THAT IT MIGHT EVEN BE A BIT COOLER THAN THE MID 30S I HAVE
ADVERTISED IN THE FORECAST....WITH COOLER TEMPERATURES EAST AND
WARMER WEST.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 336 PM CST TUE JAN 19 2016
ALOFT: VERY LITTLE CHANGE IN THE PATTERN IS ENVISIONED FOR AT LEAST
THE NEXT WEEK. A MEAN TROF WILL REMAIN OVER THE E PAC WITH THE MEAN
RIDGE OVER WRN N AMERICA. THE FLOW WILL INITIALLY BE MODERATELY
AMPLIFIED BUT WILL DEAMPLIFY TEMPORARILY AS A TROF MOWS DOWN THE
RIDGE FRI-SAT AND EMERGES INTO THE PLAINS SUN-MON. NW FLOW WILL
FOLLOW TUE.
AT 00Z/THU A SHORTWAVE TROF WILL BE MOVING IN AND AMPLIFYING...WITH
A MID-LVL CIRCULATION CLOSING OFF OVER NEB/KS BY 06Z. THIS LOW WILL
DROP SSE THU WITH QUIETER WX TO FOLLOW.
SURFACE: A WEAK COLD FRONT WILL MOVE THRU WED NIGHT. LEE
CYCLOGENESIS WILL BE UNDERWAY WED EVE WITH THE SFC LOW FAR TO THE S
OVER TX. CANADIAN HIGH PRES WILL GRADUALLY BUILD IN THU-FRI. RETURN
FLOW DEVELOPS SAT AS A CLIPPER HEADS E ACROSS SRN CANADA. A NICE
DOWNSLOPE-WARMED AIR MASS WILL OVERTAKE THE REGION...BUT SNOW ON THE
GROUND WILL TEMPER THE WARM-UP. THE NEXT PAC COOL FRONT WILL BE
MAKING ITS WAY THRU THE WRN USA AND WILL ARRIVE HERE LATE SUN. HIGH
PRES WILL MOVE IN MON AND DROP INTO THE SRN PLAINS TUE.
SOME DAILY DETAILS...
WED NIGHT: SNOW WILL BE BLOSSOMING OVER N-CNTRL KS AND EXPANDING N
INTO S-CNTRL NEB.
THU: A SWATH OF SNOW WILL PROBABLY STILL ENCOMPASS MUCH OF THE FCST
AREA THRU THE MORNING...RESULTING IN PERIODS OF SNOW. IT WILL
DIMINISH AND END IN THE AFTERNOON.
CURRENT EXPECTATION IS THAT MOST IF NOT ALL THE ACCUMULATING SNOW
WILL FALL WED NIGHT. WHILE SNOW WILL CONT INTO THU THE LIFT WILL NOT
BE ENOUGH TO RESULT IN MUCH ACCUM.
SNOW RATIOS: THIS IS TOUGH BECAUSE THE MESOSCALE NATURE OF THIS
SYSTEM WILL RESULT IN HIGHLY NON-UNIFORM LIFT. HIGHER UPWARD
VERTICAL MOTION (UVM) WILL RESULT IN HIGHER RATIOS WITHIN THE BAND.
GIVEN THAT THE BAND SHOULD BE TRANSIENT...KEPT RATIOS IN THE 10-12
RANGE.
BASED ON NAM SOUNDINGS...UVM WILL BE FAIRLY GOOD BELOW THE DGZ FROM
I-80 SOUTH. WITH TEMPS WARMER THAN -5C...THIS WILL RESULT IN
SUBSTANTIAL RIMING AND RATIOS CLOSE TO 10:1...IE A WETTER SNOW. N OF
I-80...IF THE NAM IS CORRECT UVM WILL BE WEAK RESULTING IN LESSER
QUALITY/SMALLER FLAKES. THAT TOO SUPPORTS A LOWER RATIO OF 10 OR
LESS.
ACCUMS: THESE RATIOS OFFER 1-2" AND THAT IS THE OFFICIAL FCST AT
THIS POINT...WITH 3-4" POSSIBLE IN A SMALLER AREA WHERE THE BAND IS
MORE PERSISTENT. WE JUST DON`T KNOW WHERE THAT WILL OCCUR.
SNOW ALGORITHMS FROM THE 06Z/12Z 20KM GFS AND 12Z/18Z NAM OFFER 2-4"
ACROSS MUCH OF THE FCST AREA...WITH ISOLATED 6" AMTS POSSIBLE.
THE EC CONTS TO BE ON THE HEAVY SIDE OF THE GUIDANCE DISTRIBUTION
CONSISTENTLY DUMPING ABOUT .50" SOMEWHERE NEAR ROOKS/OSBORNE/
MITCHELL COUNTIES. THAT INCLUDES THE LAST 4 RUNS. HOWEVER...THE 12Z
EC ENSEMBLE MEAN PROBABILITY FOR .50" IN 24 HRS 10% OR LESS. SO THAT
CONSTRAINS ME FROM GETTING OVERLY EXCITED.
WINDS WILL NOT BE A FACTOR WITH THIS EVENT.
FRI: DECREASING CLOUDS AS SUBSIDENT NW FLOW MOVES IN. HIGH TEMPS
PROBABLY COLDER THAN NORMAL.
SAT: TEMPS AT LEAST NORMAL IF NOT ABOVE. SNOW ON THE GROUND IS A
HUGE MITIGATING FACTOR. OTHERWISE...WIDESPREAD HIGHS IN THE 40S AND
50S WOULD BE ON THE TABLE.
SUN-MON: INCREASING CLOUDS. COOLER. POSSIBLY A TOUGH OF LIGHT
PRECIP AS THE FRONT/TROF MOVE IN.
&&
.AVIATION...(FOR THE 18Z KGRI/KEAR TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1149 AM CST TUE JAN 19 2016
TRICKY AT THE BEGINNING OF THE FORECAST AS LIGHT SNOW IS IN THE
PROCESS OF EXITING THE AREA. VISIBILITY SHOULD IMPROVE SHORTLY.
CEILINGS MAY BE QUITE VARIABLE...BUT SHOULD MAINLY BE WITHING THE
MVFR RANGE THROUGH MOST OF THE AFTERNOON. REDUCED VISIBILITY IS A
BIT OF A CONCERN LATE TONIGHT INTO WEDNESDAY MORNING...ESPECIALLY
TOWARD KEAR. LIGHT SOUTH SOUTHEAST WIND MAY ENCOURAGE DEVELOPMENT
OF BR. MODELS ARE NOT IN AGREEMENT WITH THIS AT ALL AND CONFIDENCE
IS LOW REGARDING VISIBILITY TONIGHT/WEDNESDAY MORNING.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...HEINLEIN
LONG TERM...HALBLAUB
AVIATION...HEINLEIN
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
855 AM PST TUE JAN 19 2016
.SYNOPSIS...ANOTHER STORM SYSTEM WILL MOVE INTO THE REGION TODAY
BRINGING AREAS OF CLOUDS AND LOCALLY GUSTY WINDS. PRECIPITATION
CHANCES WILL MAINLY BE CONFINED TO THE SIERRA AND HIGHER ELEVATIONS
OF THE SOUTHERN GREAT BASIN. AFTER TODAY HIGH PRESSURE WILL BUILD
OVER THE REGION BRINGING DRY CONDITIONS AND ABOVE NORMAL
TEMPERATURES THROUGH THE END OF THE WEEK.
&&
.UPDATE...JUST SENT OUT AN UPDATE TO INCREASE THE POPS FOR TODAY
ACROSS MUCH OF THE REGION. FAIRLY POTENT STORM SYSTEM IS PUSHING
INTO CALIFORNIA NOW WITH THE BACK EDGE OF THE PRECIPITATION SHIELD
JUST NOW REACHING THE SAN FRANSISCO BAY AREA. THIS MOISTURE PLUME
WILL HEAD EAST TODAY AND WHILE MUCH OF THE PRECIP WILL BE
INTERCEPTED BY THE SIERRA...A DEEP MOISTURE TAP TRACEABLE BACK TO
THE HAWAIIAN ISLANDS WILL LEAD TO SOME SPILLOVER INTO THE DESERTS AND
SOUTHERN GREAT BASIN. ALL FORECAST MODELS HAVE BOOSTED LIKELIHOODS
OF RAINFALL TODAY...AND THE HRRR ADVERTISES A SMALL BAND OF RAINFALL
LIKELY TO PUSH EAST THIS AFTERNOON AND EVENING ACROSS THE DESERTS
AND INTO NORTHWEST ARIZONA BY LATE EVENING. IF IT
MATERIALIZES...SOME LIGHT RAIN OR SPRINKLES MAY AFFECT THE EVENING
COMMUTE IN THE VEGAS METRO.
-OUTLER-
&&
.SHORT TERM...TODAY THROUGH THURSDAY NIGHT.
AS ONE SYSTEM EXITS THE REGION ANOTHER IS ALREADY STARTING TO MOVE
IN. HIGH CLOUDS WILL CONTINUE TO SPREAD OVER THE FORECAST AREA TODAY
AND WILL EVENTUALLY LOWER THROUGHOUT THE DAY. LIKE THE PREVIOUS
COUPLE OF SYSTEMS MUCH OF THE PRECIPITATION IS EXPECTED TO BE
INTERCEPTED BY THE SIERRA. HOWEVER...THIS SYSTEM MAY TAKE A TRACK
THAT WILL BRING IT A BIT FURTHER SOUTH ALLOWING FOR MORE
PRECIPITATION TO MAKE IT EAST OF THE SIERRA. THE LATEST MODEL RUNS
HAVE BEEN PROGRESSIVELY SHOWING HIGHER QPF AMOUNTS ACROSS CENTRAL
INYO...SAN BERNARDINO AND SOUTHERN NEVADA THROUGH 00Z THIS
AFTERNOON. EVEN THE LATEST HRRR HAS BEEN RAMPING UP ITS
PRECIPITATION COVERAGE WHICH SHOWS THE GREATEST POTENTIAL FOR
SHOWERS ACROSS THOSE AREAS BETWEEN 19Z-00Z. BASED ON THE LATEST RUNS
HAVE GONE AHEAD AND INCREASED POPS IN THE GRIDS. STILL THINK THAT
ANYTHING THAT DOES OCCUR EAST OF THE SIERRA WILL REMAIN LIGHT AND
AMOUNTS SHOULD GENERALLY RANGE FROM A TRACE TO A COUPLE OF
HUNDREDTHS WITH LIGHT SNOW ACCUMULATIONS IN THE HIGHER ELEVATIONS.
SHOWERS WILL THEN SPREAD EAST THIS EVENING WITH LIGHT AMOUNTS
EXPECTED ACROSS NORTHERN MOHAVE COUNTY BEFORE EXITING THE CWA
OVERNIGHT. WITH THE CLOUD COVER TODAY TEMPERATURES WILL BE HELD DOWN
SEVERAL DEGREES FROM YESTERDAY WITH READINGS CLOSE TO NORMAL.
HIGH PRESSURE IS THEN FORECAST TO DEVELOP OVER THE REGION WEDNESDAY
AND THURSDAY ALLOWING FOR DRY CONDITIONS AND TEMPERATURES WARMING TO
A FEW DEGREES ABOVE NORMAL. IT DOES LOOK LIKE THERE WILL BE ENOUGH
OF A SURFACE GRADIENT TO BRING GUSTY WINDS DOWN THE COLORADO RIVER
VALLEY WEDNESDAY NIGHT AND THURSDAY. AT THIS TIME WINDS DO NOT LOOK
TO BE STRONG ENOUGH FOR ANY ADVISORIES...BUT WINDS COULD STILL GUST
OVER 30 MPH...ESPECIALLY NEAR LAUGHLIN/BULLHEAD CITY.
.LONG TERM...FRIDAY THROUGH TUESDAY.
NOT MUCH CHANGE AGAIN TO THE LONG TERM PORTION OF THE FORECAST
TONIGHT. WE START WITH SHORTWAVE RIDGING MOVING OFF TO THE EAST IN
ADVANCE OF THE NEXT SYSTEM MOVING ONTO THE WEST COAST SOME TIME
BETWEEN 00Z AND 18Z SATURDAY BASED ON THE MODEL OF CHOICE. I AM
LEANING MORE WITH THE 00Z ECMWF TIMING (CLOSER TO 12Z-18Z SATURDAY)
GIVEN THE CLEAR TREND IN THE GFS TOWARD STRONGER RIDGING DOWNSTREAM
OF THE SYSTEM IN THE PAST 24 HOURS...SOMETHING THE ECMWF HAS BEEN
QUITE CONSISTENT ABOUT THE PAST FEW CYCLES. IN ADDITION, I AM
LEANING TOWARD THE SOMEWHAT DEEPER DEPICTION OF THE TROUGH OF THE
ECMWF COMPARED TO THE 00Z GFS...DESPITE CONSIDERABLE SUPPORT FROM
THE 00Z CMC/NAM FOR THE GFS SOLUTION. ENSEMBLE SOLUTIONS ARE
CONSIDERABLY MORE VARIED, AND AT LEAST A FEW MEMBERS SUGGEST THE
DEEPER/SLOWER APPEARANCE TO THE SYSTEM THE EURO HAS CONSISTENTLY
PROVIDED. ENSEMBLE MEANS ARE SOMEWHAT SLOWER THAN THE 00Z GFS
DETERMINISTIC SOLUTION AND THE RECENT 06Z RUN IS SLOWER/DEEPER THAN
ITS PREDECESSOR, PROVIDING ADDITIONAL SUPPORTING EVIDENCE FOR ME TO
LEAN ON THE SLOWER SIDE. GFS TENDS TO PROGRESS SYSTEMS INTO RIDGES
TOO QUICKLY, AND I SUSPECT THIS BIAS IS SHOWING UP TO SOME DEGREE.
NEVERTHELESS, FINAL GRIDS INCLUDED AT LEAST SOME CONTRIBUTION FROM
THE GFS BECAUSE OF SUBSTANTIALLY MORE SUPPORT FROM OTHER MODELS AND
FROM THE APPARENT SEASONAL BIAS OF THE ECMWF TO BE A BIT TOO
STRONG/SLOW WITH THESE PACIFIC SYSTEMS.
MODELS HAVE ALSO BEEN A LITTLE BIT MORE RELUCTANT TO START PRECIP IN
THE SIERRA DURING THE MORNING FRIDAY...SO I REDUCED POPS DURING THIS
TIME. CURRENTLY...ONSET TIMING SEEMS TO BE FRIDAY AFTERNOON/EVENING.
GFS/CMC SHUT DOWN PRECIP IN THE SIERRA QUICKLY...BY 12Z-18Z
SATURDAY...GIVEN THE FASTER/WEAKER DEPICTIONS OF TROUGH PASSAGE.
EURO KEEPS PRECIP AROUND THROUGH 00Z SUNDAY. I MAINTAINED POPS IN
THE SIERRA THROUGH THIS TIME...THOUGH THEY REMAIN IN THE SLIGHT
CHANCE CATEGORY BY THIS POINT. IF THE EURO SOLUTION VERIFIES...COULD
SEE SNOW AMOUNTS OF 6-12 INCHES ALONG THE SIERRA CREST. KEPT THEM A
BIT LOWER THAN THIS FOR NOW GIVEN THE MODEL UNCERTAINTY.
PRECIP FOR THE SOUTHERN GREAT BASIN IS FAR MORE UNCERTAIN AS THE
FARTHER NORTH TRACK OF THE GFS PROVIDES LITTLE TO NO PRECIP IN THIS
REGION WHEREAS THE ECMWF AND TO A LESSER DEGREE THE CMC PROVIDE AT
LEAST LIGHT ISOLATED/SCATTERED PRECIP THROUGH THE DAY SATURDAY. EURO
TENDS TO BE TOO AGGRESSIVE WITH PRODUCING PRECIP IN THIS AREA...AND
GIVEN THAT THE SIERRA WILL TAKE THE BRUNT OF THE PRECIP...KEPT VERY
LOW POPS IN FOR THIS REGION SATURDAY. TEMPERATURES FRIDAY AND
SATURDAY WILL BE ABOUT 2-7 DEGREES ABOVE NORMAL.
LONG-RANGE MODELS SHOW AT LEAST SOME INDICATION OF WEAK VORTICITY
MAXIMA MOVING THROUGH THE SOUTHWEST UPSTREAM OF THE SYSTEM PASSING
THROUGH ON SATURDAY. NO MATTER THE DEPICTION...LOOKS LIKE SUNDAY
WILL BE MOSTLY DRY AND COOLER AS NORTHERLY UPPER-LEVEL FLOW BECOMES
ESTABLISHED. AS THE TROUGH DEEPENS TO OUR EAST SUNDAY AND
MONDAY...HIGH AMPLITUDE RIDGING DEVELOPS ALONG THE WEST
COAST...PROVIDING OUR AREA STRONG NORTHERLY FLOW ALOFT FOR MONDAY
AND TUESDAY. THIS WILL LIKELY TRANSLATE TO BREEZY CONDITIONS IN THE
COLORADO RIVER VALLEY DURING THIS TIME. OTHERWISE...DRY CONDITIONS
AND NEAR NORMAL TEMPERATURES SHOULD START OUT THE NEW WEEK.
NEAR THE END OF THE LONG TERM...EURO FLATTENS THE NEWLY ESTABLISHED
RIDGE FAR MORE AGGRESSIVELY THAN THE GFS AS THE NEXT SYSTEM
APPROACHES THE WEST COAST. NEVERTHELESS...THE STORM TRACK REMAINS
TOO FAR NORTH AND THE SUBTROPICAL RIDGE IN THE EAST PACIFIC REMAINS
TOO STRONG TO PERMIT THIS SYSTEM TO AFFECT OUR AREA TO A SUBSTANTIAL
DEGREE. BEYOND THE LONG RANGE...ENSEMBLE SOLUTIONS HAVE CONSISTENTLY
INSISTED THAT THE SUBTROPICAL RIDGE IN THE EAST PACIFIC WILL
RETROGRESS AS FEBRUARY APPROACHES. IF SO...THIS WOULD AT LEAST
SUGGEST THAT MORE UNSETTLED WEATHER IS ON THE HORIZON. WE SHALL SEE.
&&
.AVIATION...FOR MCCARRAN...WINDS WILL GENERALLY REMAIN LIGHT AND
VARIABLE AT THE TERMINAL TODAY WINDS WIND SPEEDS REMAINING BELOW
6KTS THROUGH THE DAY. HIGH CLOUDS WILL GRADUALLY LOWER THIS MORNING
WITH CIGS AROUND 10K FEET BETWEEN 19Z-00Z THIS AFTERNOON. SCATTERED
SHOWERS ARE EXPECTED TO DEVELOP IN THE SPRING MOUNTAINS AND THERE IS
A SLIGHT CHANCE SHOWERS COULD WORK INTO THE VALLEY BETWEEN 20Z-00Z.
ANY PRECIPITATION THAT DOES FALL IS EXPECTED TO REMAIN LIGHT AND
CHANCES ARE TOO LOW TO INCLUDE IN THE TAF.
FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...SOUTH WINDS WILL INCREASE MAINLY ACROSS
INYO...ESMERALDA...AND LINCOLN COUNTIES THIS AFTERNOON AROUND 10-15
KTS WITH WINDS LESS THAN 10KTS ELSEWHERE...EXCEPT WESTERN SAN
BERNARDINO COUNTY WHERE WEST WINDS 10-20KTS WILL OCCUR.
PRECIPITATION IS LIKELY ACROSS THE SIERRA CREST...BUT ISOLATED TO
SCATTERED SHOWERS ARE FORECAST TO DEVELOP EAST OF THE CREST ACROSS
THE REMAINDER OF THE AREA THIS AFTERNOON. CIGS RANGING FROM 8-10K
FEET. PRECIPITATION AMOUNTS ARE EXPECTED TO REMAIN LIGHT.
&&
.SPOTTER INFORMATION STATEMENT...SPOTTER ACTIVATION IS NOT EXPECTED.
PLEASE REPORT ANY SIGNIFICANT WEATHER ACCORDING TO STANDARD
OPERATING PROCEDURES.
&&
$$
SHORT TERM/AVIATION...GORELOW
LONG TERM.............SHAFER
FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE:
HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
240 AM PST TUE JAN 19 2016
.SYNOPSIS...ANOTHER STORM SYSTEM WILL MOVE INTO THE REGION TODAY
BRINGING AREAS OF CLOUDS AND LOCALLY GUSTY WINDS. PRECIPITATION
CHANCES WILL MAINLY BE CONFINED TO THE SIERRA AND HIGHER ELEVATIONS
OF THE SOUTHERN GREAT BASIN. AFTER TODAY HIGH PRESSURE WILL BUILD
OVER THE REGION BRINGING DRY CONDITIONS AND ABOVE NORMAL
TEMPERATURES THROUGH THE END OF THE WEEK.
&&
.SHORT TERM...TODAY THROUGH THURSDAY NIGHT.
AS ONE SYSTEM EXITS THE REGION ANOTHER IS ALREADY STARTING TO MOVE
IN. HIGH CLOUDS WILL CONTINUE TO SPREAD OVER THE FORECAST AREA TODAY
AND WILL EVENTUALLY LOWER THROUGHOUT THE DAY. LIKE THE PREVIOUS
COUPLE OF SYSTEMS MUCH OF THE PRECIPITATION IS EXPECTED TO BE
INTERCEPTED BY THE SIERRA. HOWEVER...THIS SYSTEM MAY TAKE A TRACK
THAT WILL BRING IT A BIT FURTHER SOUTH ALLOWING FOR MORE
PRECIPITATION TO MAKE IT EAST OF THE SIERRA. THE LATEST MODEL RUNS
HAVE BEEN PROGRESSIVELY SHOWING HIGHER QPF AMOUNTS ACROSS CENTRAL
INYO...SAN BERNARDINO AND SOUTHERN NEVADA THROUGH 00Z THIS
AFTERNOON. EVEN THE LATEST HRRR HAS BEEN RAMPING UP ITS
PRECIPITATION COVERAGE WHICH SHOWS THE GREATEST POTENTIAL FOR
SHOWERS ACROSS THOSE AREAS BETWEEN 19Z-00Z. BASED ON THE LATEST RUNS
HAVE GONE AHEAD AND INCREASED POPS IN THE GRIDS. STILL THINK THAT
ANYTHING THAT DOES OCCUR EAST OF THE SIERRA WILL REMAIN LIGHT AND
AMOUNTS SHOULD GENERALLY RANGE FROM A TRACE TO A COUPLE OF
HUNDREDTHS WITH LIGHT SNOW ACCUMULATIONS IN THE HIGHER ELEVATIONS.
SHOWERS WILL THEN SPREAD EAST THIS EVENING WITH LIGHT AMOUNTS
EXPECTED ACROSS NORTHERN MOHAVE COUNTY BEFORE EXITING THE CWA
OVERNIGHT. WITH THE CLOUD COVER TODAY TEMPERATURES WILL BE HELD DOWN
SEVERAL DEGREES FROM YESTERDAY WITH READINGS CLOSE TO NORMAL.
HIGH PRESSURE IS THEN FORECAST TO DEVELOP OVER THE REGION WEDNESDAY
AND THURSDAY ALLOWING FOR DRY CONDITIONS AND TEMPERATURES WARMING TO
A FEW DEGREES ABOVE NORMAL. IT DOES LOOK LIKE THERE WILL BE ENOUGH
OF A SURFACE GRADIENT TO BRING GUSTY WINDS DOWN THE COLORADO RIVER
VALLEY WEDNESDAY NIGHT AND THURSDAY. AT THIS TIME WINDS DO NOT LOOK
TO BE STRONG ENOUGH FOR ANY ADVISORIES...BUT WINDS COULD STILL GUST
OVER 30 MPH...ESPECIALLY NEAR LAUGHLIN/BULLHEAD CITY.
.LONG TERM...FRIDAY THROUGH TUESDAY.
NOT MUCH CHANGE AGAIN TO THE LONG TERM PORTION OF THE FORECAST
TONIGHT. WE START WITH SHORTWAVE RIDGING MOVING OFF TO THE EAST IN
ADVANCE OF THE NEXT SYSTEM MOVING ONTO THE WEST COAST SOME TIME
BETWEEN 00Z AND 18Z SATURDAY BASED ON THE MODEL OF CHOICE. I AM
LEANING MORE WITH THE 00Z ECMWF TIMING (CLOSER TO 12Z-18Z SATURDAY)
GIVEN THE CLEAR TREND IN THE GFS TOWARD STRONGER RIDGING DOWNSTREAM
OF THE SYSTEM IN THE PAST 24 HOURS...SOMETHING THE ECMWF HAS BEEN
QUITE CONSISTENT ABOUT THE PAST FEW CYCLES. IN ADDITION, I AM
LEANING TOWARD THE SOMEWHAT DEEPER DEPICTION OF THE TROUGH OF THE
ECMWF COMPARED TO THE 00Z GFS...DESPITE CONSIDERABLE SUPPORT FROM
THE 00Z CMC/NAM FOR THE GFS SOLUTION. ENSEMBLE SOLUTIONS ARE
CONSIDERABLY MORE VARIED, AND AT LEAST A FEW MEMBERS SUGGEST THE
DEEPER/SLOWER APPEARANCE TO THE SYSTEM THE EURO HAS CONSISTENTLY
PROVIDED. ENSEMBLE MEANS ARE SOMEWHAT SLOWER THAN THE 00Z GFS
DETERMINISTIC SOLUTION AND THE RECENT 06Z RUN IS SLOWER/DEEPER THAN
ITS PREDECESSOR, PROVIDING ADDITIONAL SUPPORTING EVIDENCE FOR ME TO
LEAN ON THE SLOWER SIDE. GFS TENDS TO PROGRESS SYSTEMS INTO RIDGES
TOO QUICKLY, AND I SUSPECT THIS BIAS IS SHOWING UP TO SOME DEGREE.
NEVERTHELESS, FINAL GRIDS INCLUDED AT LEAST SOME CONTRIBUTION FROM
THE GFS BECAUSE OF SUBSTANTIALLY MORE SUPPORT FROM OTHER MODELS AND
FROM THE APPARENT SEASONAL BIAS OF THE ECMWF TO BE A BIT TOO
STRONG/SLOW WITH THESE PACIFIC SYSTEMS.
MODELS HAVE ALSO BEEN A LITTLE BIT MORE RELUCTANT TO START PRECIP IN
THE SIERRA DURING THE MORNING FRIDAY...SO I REDUCED POPS DURING THIS
TIME. CURRENTLY...ONSET TIMING SEEMS TO BE FRIDAY AFTERNOON/EVENING.
GFS/CMC SHUT DOWN PRECIP IN THE SIERRA QUICKLY...BY 12Z-18Z
SATURDAY...GIVEN THE FASTER/WEAKER DEPICTIONS OF TROUGH PASSAGE.
EURO KEEPS PRECIP AROUND THROUGH 00Z SUNDAY. I MAINTAINED POPS IN
THE SIERRA THROUGH THIS TIME...THOUGH THEY REMAIN IN THE SLIGHT
CHANCE CATEGORY BY THIS POINT. IF THE EURO SOLUTION VERIFIES...COULD
SEE SNOW AMOUNTS OF 6-12 INCHES ALONG THE SIERRA CREST. KEPT THEM A
BIT LOWER THAN THIS FOR NOW GIVEN THE MODEL UNCERTAINTY.
PRECIP FOR THE SOUTHERN GREAT BASIN IS FAR MORE UNCERTAIN AS THE
FARTHER NORTH TRACK OF THE GFS PROVIDES LITTLE TO NO PRECIP IN THIS
REGION WHEREAS THE ECMWF AND TO A LESSER DEGREE THE CMC PROVIDE AT
LEAST LIGHT ISOLATED/SCATTERED PRECIP THROUGH THE DAY SATURDAY. EURO
TENDS TO BE TOO AGGRESSIVE WITH PRODUCING PRECIP IN THIS AREA...AND
GIVEN THAT THE SIERRA WILL TAKE THE BRUNT OF THE PRECIP...KEPT VERY
LOW POPS IN FOR THIS REGION SATURDAY. TEMPERATURES FRIDAY AND
SATURDAY WILL BE ABOUT 2-7 DEGREES ABOVE NORMAL.
LONG-RANGE MODELS SHOW AT LEAST SOME INDICATION OF WEAK VORTICITY
MAXIMA MOVING THROUGH THE SOUTHWEST UPSTREAM OF THE SYSTEM PASSING
THROUGH ON SATURDAY. NO MATTER THE DEPICTION...LOOKS LIKE SUNDAY
WILL BE MOSTLY DRY AND COOLER AS NORTHERLY UPPER-LEVEL FLOW BECOMES
ESTABLISHED. AS THE TROUGH DEEPENS TO OUR EAST SUNDAY AND
MONDAY...HIGH AMPLITUDE RIDGING DEVELOPS ALONG THE WEST
COAST...PROVIDING OUR AREA STRONG NORTHERLY FLOW ALOFT FOR MONDAY
AND TUESDAY. THIS WILL LIKELY TRANSLATE TO BREEZY CONDITIONS IN THE
COLORADO RIVER VALLEY DURING THIS TIME. OTHERWISE...DRY CONDITIONS
AND NEAR NORMAL TEMPERATURES SHOULD START OUT THE NEW WEEK.
NEAR THE END OF THE LONG TERM...EURO FLATTENS THE NEWLY ESTABLISHED
RIDGE FAR MORE AGGRESSIVELY THAN THE GFS AS THE NEXT SYSTEM
APPROACHES THE WEST COAST. NEVERTHELESS...THE STORM TRACK REMAINS
TOO FAR NORTH AND THE SUBTROPICAL RIDGE IN THE EAST PACIFIC REMAINS
TOO STRONG TO PERMIT THIS SYSTEM TO AFFECT OUR AREA TO A SUBSTANTIAL
DEGREE. BEYOND THE LONG RANGE...ENSEMBLE SOLUTIONS HAVE CONSISTENTLY
INSISTED THAT THE SUBTROPICAL RIDGE IN THE EAST PACIFIC WILL
RETROGRESS AS FEBRUARY APPROACHES. IF SO...THIS WOULD AT LEAST
SUGGEST THAT MORE UNSETTLED WEATHER IS ON THE HORIZON. WE SHALL SEE.
&&
.AVIATION...FOR MCCARRAN...WINDS WILL GENERALLY REMAIN LIGHT AND
VARIABLE AT THE TERMINAL TODAY WINDS WIND SPEEDS REMAINING BELOW
6KTS THROUGH THE DAY. HIGH CLOUDS WILL GRADUALLY LOWER THIS MORNING
WITH CIGS AROUND 10K FEET BETWEEN 19Z-00Z THIS AFTERNOON. SCATTERED
SHOWERS ARE EXPECTED TO DEVELOP IN THE SPRING MOUNTAINS AND THERE IS
A SLIGHT CHANCE SHOWERS COULD WORK INTO THE VALLEY BETWEEN 20Z-00Z.
ANY PRECIPITATION THAT DOES FALL IS EXPECTED TO REMAIN LIGHT AND
CHANCES ARE TOO LOW TO INCLUDE IN THE TAF.
FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...SOUTH WINDS WILL INCREASE MAINLY ACROSS
INYO...ESMERALDA...AND LINCOLN COUNTIES THIS AFTERNOON AROUND 10-15
KTS WITH WINDS LESS THAN 10KTS ELSEWHERE...EXCEPT WESTERN SAN
BERNARDINO COUNTY WHERE WEST WINDS 10-20KTS WILL OCCUR.
PRECIPITATION IS LIKELY ACROSS THE SIERRA CREST...BUT ISOLATED TO
SCATTERED SHOWERS ARE FORECAST TO DEVELOP EAST OF THE CREST ACROSS
THE REMAINDER OF THE AREA THIS AFTERNOON. CIGS RANGING FROM 8-10K
FEET. PRECIPITATION AMOUNTS ARE EXPECTED TO REMAIN LIGHT.
&&
.SPOTTER INFORMATION STATEMENT...SPOTTER ACTIVATION IS NOT EXPECTED.
PLEASE REPORT ANY SIGNIFICANT WEATHER ACCORDING TO STANDARD
OPERATING PROCEDURES.
&&
$$
SHORT TERM/AVIATION...GORELOW
LONG TERM.............SHAFER
FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE:
HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
932 PM EST WED JAN 20 2016
.SYNOPSIS...
SURFACE HIGH PRESSURE BUILDING EASTWARD FROM THE NORTHERN GREAT
LAKES WILL BRING AN EXTENDED PERIOD OF DRY WEATHER THROUGH THE
REMAINDER OF THIS WEEK AND THROUGH THE UPCOMING WEEKEND.
TEMPERATURES WILL BE NEAR AVERAGE FOR MID JANUARY THROUGH
SATURDAY...AND THEN MODERATE ABOVE AVERAGE FOR THE EARLY PART OF
NEXT WEEK.
&&
.NEAR TERM /UNTIL 10 AM THURSDAY MORNING/...
AS OF 928 PM EST WEDNESDAY...TRANQUIL WEATHER CONDITIONS CONTINUE
OVERNIGHT. THERE IS AN UPSTREAM UPPER LOW CENTERED EAST OF LAKE
ONTARIO PER IR IMAGERY. THIS SYSTEM WILL CONTINUE SHIFT EASTWARD
WHILE WEAKENING OVERNIGHT. ONLY AFFECT ON WEATHER CONDITIONS
ACROSS THE NORTH COUNTRY SHOULD BE A PERIOD OF MID-UPR LEVEL
CLOUDS OVERNIGHT WHICH ARE STARTING TO MOVE INTO THE ST LAWRENCE
VALLEY; PRECIPITATION IS NOT EXPECTED WITH DRY LOW- LEVEL
CONDITIONS PERSISTING. WINDS AROUND 5-10 MPH OUT OF THE NORTHWEST
AS BOUNDARY LAYER STABILIZES. LOW TEMPS WILL BE SEASONABLE FOR
MID- JANUARY...GENERALLY IN THE SINGLE DIGITS ABOVE ZERO...BUT
LOCALLY AROUND 13F AT BTV AND SLIGHTLY BELOW IN THE COLDER SPOTS
OF THE NRN ADIRONDACKS.
PARTLY TO MOSTLY SUNNY AND DRY FOR THURSDAY...WITH HIGHS GENERALLY
IN THE LOW-MID 20S. CONTINUED NW SURFACE WINDS...GENERALLY 5-10 MPH.
POPS NIL.
&&
.SHORT TERM /10 AM THURSDAY MORNING THROUGH FRIDAY/...
AS OF 325 PM EST WEDNESDAY...VERY QUIET WEATHER EXPECTED WITH
1030MB SURFACE HIGH PRESSURE BUILDING FROM THE CENTRAL GREAT LAKES
INTO NORTHERN NEW YORK. WEAK 5H VORT IN THE NORTHWEST FLOW
ALOFT...ALONG WITH A SMALL RIBBON OF ENHANCED MID LEVEL MOISTURE
MAY PRODUCE A FEW FLURRIES ACROSS THE NORTHERN MOUNTAINS ON
THURSDAY NIGHT. TEMPERATURES WILL BE HIGHLY DEPEND UPON WINDS AND
CLOUDS...BUT IF EVEN CLEARING CAN OCCUR WITH SURFACE HIGH
PRES...THINKING LOWS WILL RANGE FROM -10F AT SLK/NORTHEAST KINGDOM
TO SINGLE DIGITS TO NEAR 10F IN THE CHAMPLAIN VALLEY. PROGGED
850MB TEMPS WARM BETWEEN -10C AND -12C BY 18Z FRIDAY...SUPPORTS
NEAR NORMAL TEMPERATURES FOR THE NORTH COUNTRY WITH DRY
CONDITIONS.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
AS OF 325 PM EST WEDNESDAY...ALL MODELS IN EXCELLENT
AGREEMENT WITH TAKING MID ATLANTIC COASTAL SYSTEM FROM NEAR NORFOLK
VA ON 12Z SATURDAY TO SOUTH OF THE BENCHMARK BY SUNDAY...WITH NO
IMPACTS ACROSS OUR CWA. THE COMBINATION OF 1030MB HIGH PRESS
ANCHORED OVER SOUTHERN CANADA AND NO PHASING WITH 5H VORT OVER THE
GREAT LAKES AND ASSOCIATED FAST WEST TO EAST POLAR JET WILL PREVENT
SYSTEM FROM IMPACTING OUR REGION. AS NORTHERN STREAM SHORT WAVE
ENERGY DROPS FROM THE GREAT LAKES INTO SOUTHERN CANADA BY 12Z SUNDAY
WILL TO PUSH MAJOR COASTAL SYSTEM OUT TO SEA. THIS WILL RESULT IN A
VERY QUIET AND DRY WEATHER WEEKEND FOR OUR REGION WITH ABOVE NORMAL
TEMPERATURES. DEVELOPING MID/UPPER LEVEL RIDGE BUILDS ON SUNDAY WITH
PROGGED 850MB TEMPS WARMING BETWEEN -3C AND -5C. THIS SUPPORTS DRY
CONDITIONS WITH TEMPERATURES MAINLY IN THE 30S. EXPECTING A LARGE
DIURNAL SWING IN DAILY TEMPS FROM COOL OVERNIGHT LOWS AND MILD
DAYTIME HIGHS DUE TO THE DRY AIR IN PLACE. HAVE GONE SEVERAL
DEGREES ABOVE GUIDANCE FOR DAYTIME HIGHS WITH MAINLY CLEAR SKIES
EXPECTED.
OUR NEXT WEAK SYSTEM ARRIVES ON TUESDAY WITH SURFACE LOW PRES
TRACKING ACROSS THE SAINT LAWRENCE VALLEY. THIS SYSTEM LOOKS TO BE
FAST MOVING WITH LIMITED IMPACTS EXPECTED FOR OUR REGION. WILL
MENTION HIGH CHC POPS WITH GENERALLY LIGHT QPF/SNOWFALL EXPECTED.
GIVEN WARM BOUNDARY LAYER TEMPS...SOME MIXED OF RAIN/SNOW IS
POSSIBLE IN THE VALLEYS. PROGGED 925MB TO 850MB THERMAL PROFILES
SUPPORT TEMPS MAINLY BETWEEN -1C AND -3C...WITH HIGHS IN THE 30S AND
LOWS IN THE MID TEENS TO MID 20S.
&&
.AVIATION /03Z THURSDAY THROUGH MONDAY/...
THROUGH 00Z THURSDAY...MAINLY VFR AND NO PCPN THROUGH THE PERIOD
UNDER LIGHT WESTERLY FLOW GENERALLY LESS THAN 10 KTS. SCT/BKN MID
TO HIGH CIGS IN THE 050-150 AGL RANGE GENERALLY EXPECTED THROUGH
12Z, TRENDING MAINLY SKC THEREAFTER AS WEAK SHORTWAVE ENERGY SHEARS
OUT TO OUR SOUTH AND WEST. ONLY EXCEPTION WILL BE A POTENTIAL
WINDOW OF MVFR STRATUS AT KSLK 04-10Z. NAM, RAP AND WRF-BASED
MODEL RH OUTPUT SEEMS OVERLY AGRESSIVE ON BRINGING LOWER MVFR STRATUS
ACROSS THE ENTIRE AREA OVERNIGHT AND OPTED TO DOWNPLAY THIS
POSSIBILITY FOR NOW AS INITIALIZATION IS ALREADY IN ERROR. LEANED
MORE HEAVILY TOWARD A LAMP-BASED SOLUTION. CONFIDENCE MODERATE.
OUTLOOK 00Z THURSDAY THROUGH MONDAY...GENERALLY VFR WITH HIGH
PRESSURE IN CONTROL.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...BANACOS
NEAR TERM...BANACOS/MV
SHORT TERM...TABER
LONG TERM...TABER
AVIATION...BANACOS/JMG
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
620 PM EST WED JAN 20 2016
.SYNOPSIS...
SURFACE HIGH PRESSURE BUILDING EASTWARD FROM THE NORTHERN GREAT
LAKES WILL BRING AN EXTENDED PERIOD OF DRY WEATHER THROUGH THE
REMAINDER OF THIS WEEK AND THROUGH THE UPCOMING WEEKEND.
TEMPERATURES WILL BE NEAR AVERAGE FOR MID JANUARY THROUGH
SATURDAY...AND THEN MODERATE ABOVE AVERAGE FOR THE EARLY PART OF
NEXT WEEK.
&&
.NEAR TERM /THROUGH THURSDAY/...
AS OF 618 PM EST WEDNESDAY...TRANQUIL WEATHER CONDITIONS EXPECTED
THIS EVENING AND OVERNIGHT. THERE IS AN UPSTREAM UPPER LOW
CENTERED ACROSS CENTRAL LOWER MICHIGAN PER IR IMAGERY. THIS SYSTEM
WILL SHIFT EWD WHILE WEAKENING OVERNIGHT. ONLY AFFECT ON SENSIBLE
WEATHER CONDITIONS ACROSS THE NORTH COUNTRY SHOULD BE A PERIOD OF
MID-UPR LEVEL CLOUDS OVERNIGHT; PRECIPITATION IS NOT EXPECTED WITH
DRY LOW-LEVEL CONDITIONS PERSISTING. WINDS AROUND 5-10 MPH OUT OF
THE NORTHWEST AS BOUNDARY LAYER STABILIZES. LOW TEMPS WILL BE
SEASONABLE FOR MID- JANUARY...GENERALLY IN THE SINGLE DIGITS ABOVE
ZERO...BUT LOCALLY AROUND 10F AT BTV AND ZERO OR SLIGHTLY BELOW IN
THE COLDER SPOTS OF THE NRN ADIRONDACKS.
PARTLY TO MOSTLY SUNNY AND DRY FOR THURSDAY...WITH HIGHS GENERALLY
IN THE LOW-MID 20S. CONTINUED NW SURFACE WINDS...GENERALLY 5-10 MPH.
POPS NIL.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY/...
AS OF 325 PM EST WEDNESDAY...VERY QUIET WEATHER EXPECTED WITH
1030MB SURFACE HIGH PRESSURE BUILDING FROM THE CENTRAL GREAT LAKES
INTO NORTHERN NEW YORK. WEAK 5H VORT IN THE NORTHWEST FLOW
ALOFT...ALONG WITH A SMALL RIBBON OF ENHANCED MID LEVEL MOISTURE
MAY PRODUCE A FEW FLURRIES ACROSS THE NORTHERN MOUNTAINS ON
THURSDAY NIGHT. TEMPERATURES WILL BE HIGHLY DEPEND UPON WINDS AND
CLOUDS...BUT IF EVEN CLEARING CAN OCCUR WITH SURFACE HIGH
PRES...THINKING LOWS WILL RANGE FROM -10F AT SLK/NORTHEAST KINGDOM
TO SINGLE DIGITS TO NEAR 10F IN THE CHAMPLAIN VALLEY. PROGGED
850MB TEMPS WARM BETWEEN -10C AND -12C BY 18Z FRIDAY...SUPPORTS
NEAR NORMAL TEMPERATURES FOR THE NORTH COUNTRY WITH DRY
CONDITIONS.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
AS OF 325 PM EST WEDNESDAY...ALL MODELS IN EXCELLENT
AGREEMENT WITH TAKING MID ATLANTIC COASTAL SYSTEM FROM NEAR NORFOLK
VA ON 12Z SATURDAY TO SOUTH OF THE BENCHMARK BY SUNDAY...WITH NO
IMPACTS ACROSS OUR CWA. THE COMBINATION OF 1030MB HIGH PRESS
ANCHORED OVER SOUTHERN CANADA AND NO PHASING WITH 5H VORT OVER THE
GREAT LAKES AND ASSOCIATED FAST WEST TO EAST POLAR JET WILL PREVENT
SYSTEM FROM IMPACTING OUR REGION. AS NORTHERN STREAM SHORT WAVE
ENERGY DROPS FROM THE GREAT LAKES INTO SOUTHERN CANADA BY 12Z SUNDAY
WILL TO PUSH MAJOR COASTAL SYSTEM OUT TO SEA. THIS WILL RESULT IN A
VERY QUIET AND DRY WEATHER WEEKEND FOR OUR REGION WITH ABOVE NORMAL
TEMPERATURES. DEVELOPING MID/UPPER LEVEL RIDGE BUILDS ON SUNDAY WITH
PROGGED 850MB TEMPS WARMING BETWEEN -3C AND -5C. THIS SUPPORTS DRY
CONDITIONS WITH TEMPERATURES MAINLY IN THE 30S. EXPECTING A LARGE
DIURNAL SWING IN DAILY TEMPS FROM COOL OVERNIGHT LOWS AND MILD
DAYTIME HIGHS DUE TO THE DRY AIR IN PLACE. HAVE GONE SEVERAL
DEGREES ABOVE GUIDANCE FOR DAYTIME HIGHS WITH MAINLY CLEAR SKIES
EXPECTED.
OUR NEXT WEAK SYSTEM ARRIVES ON TUESDAY WITH SURFACE LOW PRES
TRACKING ACROSS THE SAINT LAWRENCE VALLEY. THIS SYSTEM LOOKS TO BE
FAST MOVING WITH LIMITED IMPACTS EXPECTED FOR OUR REGION. WILL
MENTION HIGH CHC POPS WITH GENERALLY LIGHT QPF/SNOWFALL EXPECTED.
GIVEN WARM BOUNDARY LAYER TEMPS...SOME MIXED OF RAIN/SNOW IS
POSSIBLE IN THE VALLEYS. PROGGED 925MB TO 850MB THERMAL PROFILES
SUPPORT TEMPS MAINLY BETWEEN -1C AND -3C...WITH HIGHS IN THE 30S AND
LOWS IN THE MID TEENS TO MID 20S.
&&
.AVIATION /23Z WEDNESDAY THROUGH MONDAY/...
THROUGH 00Z THURSDAY...MAINLY VFR AND NO PCPN THROUGH THE PERIOD
UNDER LIGHT WESTERLY FLOW GENERALLY LESS THAN 10 KTS. SCT/BKN MID
TO HIGH CIGS IN THE 050-150 AGL RANGE GENERALLY EXPECTED THROUGH
12Z, TRENDING MAINLY SKC THEREAFTER AS WEAK SHORTWAVE ENERGY SHEARS
OUT TO OUR SOUTH AND WEST. ONLY EXCEPTION WILL BE A POTENTIAL
WINDOW OF MVFR STRATUS AT KSLK 04-10Z. NAM, RAP AND WRF-BASED
MODEL RH OUTPUT SEEMS OVERLY AGRESSIVE ON BRINGING LOWER MVFR STRATUS
ACROSS THE ENTIRE AREA OVERNIGHT AND OPTED TO DOWNPLAY THIS
POSSIBILITY FOR NOW AS INITIALIZATION IS ALREADY IN ERROR. LEANED
MORE HEAVILY TOWARD A LAMP-BASED SOLUTION. CONFIDENCE MODERATE.
OUTLOOK 00Z THURSDAY THROUGH MONDAY...GENERALLY VFR WITH HIGH
PRESSURE IN CONTROL.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...BANACOS
NEAR TERM...BANACOS/MV
SHORT TERM...TABER
LONG TERM...TABER
AVIATION...BANACOS/JMG
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
609 PM EST WED JAN 20 2016
.SYNOPSIS...
SURFACE HIGH PRESSURE BUILDING EASTWARD FROM THE NORTHERN GREAT
LAKES WILL BRING AN EXTENDED PERIOD OF DRY WEATHER THROUGH THE
REMAINDER OF THIS WEEK AND THROUGH THE UPCOMING WEEKEND.
TEMPERATURES WILL BE NEAR AVERAGE FOR MID JANUARY THROUGH
SATURDAY...AND THEN MODERATE ABOVE AVERAGE FOR THE EARLY PART OF
NEXT WEEK.
&&
.NEAR TERM /THROUGH THURSDAY/...
AS OF 334 PM EST WEDNESDAY...TRANQUIL WEATHER CONDITIONS EXPECTED
THIS EVENING AND OVERNIGHT. REMNANT STRATUS ARE GENERALLY
DISSIPATING ACROSS NERN VT AT 20Z...AND FLURRY ACTIVITY HAS ENDED
BASED ON SURFACE OBSERVATIONS. THERE IS AN UPSTREAM UPPER LOW
CENTERED ACROSS CENTRAL LOWER MICHIGAN PER IR IMAGERY. THIS SYSTEM
WILL SHIFT EWD WHILE WEAKENING OVERNIGHT. ONLY AFFECT ON SENSIBLE
WEATHER CONDITIONS ACROSS THE NORTH COUNTRY SHOULD BE A PERIOD OF
MID-UPR LEVEL CLOUDS OVERNIGHT; PRECIPITATION IS NOT EXPECTED WITH
DRY LOW-LEVEL CONDITIONS PERSISTING. NW WINDS 10-15 MPH...WILL
DECREASE TO AROUND 5 MPH AS BOUNDARY LAYER STABILIZES NEAR/AFTER
SUNSET. LOW TEMPS WILL BE SEASONABLE FOR MID-JANUARY...GENERALLY
IN THE SINGLE DIGITS ABOVE ZERO...BUT LOCALLY AROUND 10F AT BTV
AND ZERO OR SLIGHTLY BELOW IN THE COLDER SPOTS OF THE NRN
ADIRONDACKS.
PARTLY TO MOSTLY SUNNY AND DRY FOR THURSDAY...WITH HIGHS GENERALLY
IN THE LOW-MID 20S. CONTINUED NW SURFACE WINDS...GENERALLY 5-10 MPH.
POPS NIL.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY/...
AS OF 325 PM EST WEDNESDAY...VERY QUIET WEATHER EXPECTED WITH
1030MB SURFACE HIGH PRESSURE BUILDING FROM THE CENTRAL GREAT LAKES
INTO NORTHERN NEW YORK. WEAK 5H VORT IN THE NORTHWEST FLOW
ALOFT...ALONG WITH A SMALL RIBBON OF ENHANCED MID LEVEL MOISTURE
MAY PRODUCE A FEW FLURRIES ACROSS THE NORTHERN MOUNTAINS ON
THURSDAY NIGHT. TEMPERATURES WILL BE HIGHLY DEPEND UPON WINDS AND
CLOUDS...BUT IF EVEN CLEARING CAN OCCUR WITH SURFACE HIGH
PRES...THINKING LOWS WILL RANGE FROM -10F AT SLK/NORTHEAST KINGDOM
TO SINGLE DIGITS TO NEAR 10F IN THE CHAMPLAIN VALLEY. PROGGED
850MB TEMPS WARM BETWEEN -10C AND -12C BY 18Z FRIDAY...SUPPORTS
NEAR NORMAL TEMPERATURES FOR THE NORTH COUNTRY WITH DRY
CONDITIONS.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
AS OF 325 PM EST WEDNESDAY...ALL MODELS IN EXCELLENT
AGREEMENT WITH TAKING MID ATLANTIC COASTAL SYSTEM FROM NEAR NORFOLK
VA ON 12Z SATURDAY TO SOUTH OF THE BENCHMARK BY SUNDAY...WITH NO
IMPACTS ACROSS OUR CWA. THE COMBINATION OF 1030MB HIGH PRESS
ANCHORED OVER SOUTHERN CANADA AND NO PHASING WITH 5H VORT OVER THE
GREAT LAKES AND ASSOCIATED FAST WEST TO EAST POLAR JET WILL PREVENT
SYSTEM FROM IMPACTING OUR REGION. AS NORTHERN STREAM SHORT WAVE
ENERGY DROPS FROM THE GREAT LAKES INTO SOUTHERN CANADA BY 12Z SUNDAY
WILL TO PUSH MAJOR COASTAL SYSTEM OUT TO SEA. THIS WILL RESULT IN A
VERY QUIET AND DRY WEATHER WEEKEND FOR OUR REGION WITH ABOVE NORMAL
TEMPERATURES. DEVELOPING MID/UPPER LEVEL RIDGE BUILDS ON SUNDAY WITH
PROGGED 850MB TEMPS WARMING BETWEEN -3C AND -5C. THIS SUPPORTS DRY
CONDITIONS WITH TEMPERATURES MAINLY IN THE 30S. EXPECTING A LARGE
DIURNAL SWING IN DAILY TEMPS FROM COOL OVERNIGHT LOWS AND MILD
DAYTIME HIGHS DUE TO THE DRY AIR IN PLACE. HAVE GONE SEVERAL
DEGREES ABOVE GUIDANCE FOR DAYTIME HIGHS WITH MAINLY CLEAR SKIES
EXPECTED.
OUR NEXT WEAK SYSTEM ARRIVES ON TUESDAY WITH SURFACE LOW PRES
TRACKING ACROSS THE SAINT LAWRENCE VALLEY. THIS SYSTEM LOOKS TO BE
FAST MOVING WITH LIMITED IMPACTS EXPECTED FOR OUR REGION. WILL
MENTION HIGH CHC POPS WITH GENERALLY LIGHT QPF/SNOWFALL EXPECTED.
GIVEN WARM BOUNDARY LAYER TEMPS...SOME MIXED OF RAIN/SNOW IS
POSSIBLE IN THE VALLEYS. PROGGED 925MB TO 850MB THERMAL PROFILES
SUPPORT TEMPS MAINLY BETWEEN -1C AND -3C...WITH HIGHS IN THE 30S AND
LOWS IN THE MID TEENS TO MID 20S.
&&
.AVIATION /00Z WEDNESDAY THROUGH MONDAY/...
THROUGH 00Z THURSDAY...MAINLY VFR AND NO PCPN THROUGH THE PERIOD
UNDER LIGHT WESTERLY FLOW GENERALLY LESS THAN 10 KTS. SCT/BKN MID
TO HIGH CIGS IN THE 050-150 AGL RANGE GENERALLY EXPECTED THROUGH
12Z, TRENDING MAINLY SKC THEREAFTER AS WEAK SHORTWAVE ENERGY SHEARS
OUT TO OUR SOUTH AND WEST. ONLY EXCEPTION WILL BE A POTENTIAL
WINDOW OF MVFR STRATUS AT KSLK 04-10Z. NAM, RAP AND WRF-BASED
MODEL RH OUTPUT SEEMS OVERLY AGRESSIVE ON BRINGING LOWER MVFR STRATUS
ACROSS THE ENTIRE AREA OVERNIGHT AND OPTED TO DOWNPLAY THIS
POSSIBILITY FOR NOW AS INITIALIZATION IS ALREADY IN ERROR. LEANED
MORE HEAVILY TOWARD A LAMP-BASED SOLUTION. CONFIDENCE MODERATE.
OUTLOOK 00Z THURSDAY THROUGH MONDAY...GENERALLY VFR WITH HIGH
PRESSURE IN CONTROL.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...BANACOS
NEAR TERM...BANACOS
SHORT TERM...TABER
LONG TERM...TABER
AVIATION...JMG/BANACOS
AREA FORECAST DISCUSSION
NWS BISMARCK ND
936 PM CST WED JAN 20 2016
.UPDATE...
ISSUED AT 936 PM CST WED JAN 20 2016
WE HAVE UPDATED TO EXPAND THE FOG MENTION INTO SOUTHWEST ND BASED
ON THE 1/4SM VISIBILITY REPORTED BY THE DICKINSON ASOS AT 03 UTC.
THE FOG IS STILL NOT PARTICULARLY WIDESPREAD...WITH THE OBSERVED
VISIBILITIES AT GLEN ULLIN AND TIOGA BOTH HAVING IMPROVED IN THE
LAST 30 MINUTES AFTER BEING UNDER 1SM EARLIER. THE BISMARCK RAOB
FROM 00 UTC AND MODIFIED RICHARDSON NUMBER OUTPUT IN BUFKIT BOTH
SUGGEST THE BOUNDARY LAYER MAY BE A BIT TOO DECOUPLED/TURBULENT
FOR LONG-LIVED AND WIDESPREAD FOG DEVELOPMENT WITHOUT A SURFACE-
BASED INVERSION. THAT MAY ALSO BE WHY HRRR RUNS THIS EVENING HAVE
CORRECTLY ASSIMILATED OBSERVED LOW VISIBILITIES FOR THEIR 00-HOUR
INITIALIZATIONS AND QUICKLY REMOVED IT BY THEIR HOUR-02 FORECAST.
GIVEN THIS SCENARIO...WE STILL EXPECT FOG MAY LIFT OVER WESTERN ND
AFTER MIDNIGHT...AND LINGER IN A RATHER MODEST FASHION CENTRAL.
OTHERWISE...ONCE AGAIN THIS UPDATE ONLY YIELDED MINOR ADJUSTMENTS
TO THE REMAINDER OF THE FORECAST...WITH LOW-END SNOW CHANCES OVER
WESTERN ND OVERNIGHT AS A WEAK SHORTWAVE TROUGH APPROACHES.
UPDATE ISSUED AT 619 PM CST WED JAN 20 2016
FOG HAS DEVELOPED AND REDUCED VISIBILITY TO LESS THAN 1SM IN THE
TIOGA AND STANLEY AREAS SINCE 23 UTC...SO WE SPREAD THE MENTION OF
FOG INTO NORTHWEST ND THIS EVENING. WE WILL MONITOR TRENDS IN CASE
VISIBILITY REDUCTIONS BECOME LOW ENOUGH FOR A LONG ENOUGH TIME TO
REQUIRE A DENSE FOG ADVISORY...BUT RECENT HRRR SIMULATIONS SUGGEST
FOG WILL NOT BE AS PREVALENT AS LAST NIGHT AS MID- AND HIGH-LEVEL
CLOUD COVER INCREASES. OTHER THAN ADJUSTING THE FOG MENTION...FEW
CHANGES WERE MADE WITH THIS UPDATE.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 247 PM CST WED JAN 20 2016
MAIN CONCERNS THIS PERIOD WILL BE FOG THIS EVENING AND OVERNIGHT
THEN LIGHT SNOW TONIGHT AND THURSDAY.
FOG HAS BEEN SLOW TO LIFT ACROSS THE NORTHERN JAMES RIVER VALLEY
WITH VISIBILITIES AROUND ONE HALF MILE MUCH OF THE AFTERNOON. AS
MID/HIGH CLOUDS OVERSPREAD THE REGION EXPECT THE FOG TO GRADUALLY
IMPROVE INTO THE EVENING HOURS. BUFKIT SOUNDINGS SHOW LOW LEVEL
SATURATION OVER THE JAMESTOWN-BISMARCK-MINOT AREA SO HAVE KEPT FOG
IN THROUGH TONIGHT THIS AREA.
A BUILDING H500 RIDGE OVER THE WEST COAST THROUGH 36 HOURS WILL
NUDGE A WEAK SHORTWAVE DOWN THE EAST SIDE OF IN INTO THE NORTHERN
PLAINS AND WEAKLY IMPACT NORTH DAKOTA TONIGHT AND THURSDAY. TODAYS
DETERMINISTIC MODEL RUNS HAVE BEEN LESS ROBUST IN GENERATING
PRECIPITATION THAN PREVIOUS ONES. GENERALLY LOWERED POPS INTO THE
CHANCE CATEGORY TONIGHT AND THURSDAY. SNOW FALL TOTALS REMAIN BELOW
ONE INCH.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 247 PM CST WED JAN 20 2016
MAIN MESSAGE WILL BE THE BRIEF WARMING TREND SLATED FOR FRIDAY AND
SATURDAY. AN UPPER LEVEL RIDGE WILL SHIFT FROM THE NORTHERN ROCKIES
INTO THE NORTHERN HIGH PLAINS FRIDAY. THE RIDGE SHIFTS EAST SATURDAY
AS HEIGHTS FLATTEN IN RESPONSE TO A SHORTWAVE AND SURFACE LOW MOVING
ACROSS SOUTHERN CANADA. THE NAEFS (NORTH AMERICAN ENSEMBLE FORECAST
SYSTEM) SITUATION TABLE SHOWS H85-H7 TEMPS IN THE 90TH TO 97TH
PERCENTILE FRIDAY THROUGH SATURDAY. MAX 850MB TEMPS OF +6C TO +8C
WILL SLIDE ACROSS WESTERN AND CENTRAL NORTH DAKOTA DURING THIS TIME
PERIOD. HOWEVER...THE NAM/GFS BUFKIT SOUNDINGS ADVERTISE QUITE A BIT
OF LOW LEVEL MOISTURE TRAPPED UNDERNEATH THE WARMER TEMPERATURES
ALOFT/INVERSION FRIDAY...BUT NOT AS MUCH BY SATURDAY AFTERNOON.
THUS OTHER THAN FAR WESTERN NORTH DAKOTA FRIDAY...WE PROBABLY WILL
NOT BE ABLE TO REALIZE THE MAXIMUM WARMTH ALOFT/MIXING TO THE
SURFACE UNTIL SATURDAY...AS MORE SUNSHINE AND THE PASSAGE OF A
SURFACE TROUGH/PSEUDO COLD FRONT OCCURS. HIGHS FRIDAY WILL RANGE
FROM THE 20S CENTRAL TO MID AND UPPER 30S WEST. BY SATURDAY HIGHS OF
33F TO 43F ARE EXPECTED ACROSS WESTERN AND CENTRAL NORTH DAKOTA.
THE MAIN COLD FRONT AND MAXIMUM COLD AIR ADVECTION SLIDES THROUGH
SATURDAY NIGHT INTO SUNDAY. THIS WILL OCCUR IN CONJUNCTION WITH A
SHORTWAVE COMING IN FROM THE WEST RESULTING IN A CHANCE OF SNOW
SUNDAY AND POSSIBLY INTO MONDAY. THE GFS AND ECMWF ARE NOT IN
AGREEMENT WITH THE TIMING OF SNOW. THE GFS ADVERTISES A DRY SUNDAY
AND SOME SNOW MONDAY...WHILE THE ECMWF SHOWS CHANCES OF SNOW SUNDAY
BUT VERY LITTLE MONDAY. IT WOULD APPEAR THE SUPERBLEND IS IN FAVOR
OF THE ECMWF WITH SUNDAY/SUNDAY NIGHT BEING THE FAVORED TIME FOR
SNOW. COLDER TEMPERATURES WILL ENSUE SUNDAY THROUGH WEDNESDAY WITH
HIGHS MOSTLY IN THE 20S. THE WEATHER COULD A BIT MORE ACTIVE MIDWEEK
AND ONWARD AS A SERIES OF CLIPPERS ARE POSSIBLE...PER GFS AND
ECMWF.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 936 PM CST WED JAN 20 2016
WIDESPREAD IFR TO LIFR CONDITIONS IN LOW CLOUDS AND SOME FOG WILL
PREVAIL ACROSS MOST OF WESTERN AND CENTRAL ND TONIGHT AND THURSDAY
MORNING. LIGHT SNOW IS POSSIBLE OVER WESTERN ND AS WELL AS A WEAK
DISTURBANCE CROSSES THE REGION. BY THURSDAY AFTERNOON...THERE MAY
BE SOME IMPROVEMENT IN CEILINGS...BUT CONFIDENCE IS LOW.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...CJS
SHORT TERM...WAA
LONG TERM...KS
AVIATION...CJS
AREA FORECAST DISCUSSION
NWS BISMARCK ND
619 PM CST WED JAN 20 2016
.UPDATE...
ISSUED AT 619 PM CST WED JAN 20 2016
FOG HAS DEVELOPED AND REDUCED VISIBILITY TO LESS THAN 1SM IN THE
TIOGA AND STANLEY AREAS SINCE 23 UTC...SO WE SPREAD THE MENTION OF
FOG INTO NORTHWEST ND THIS EVENING. WE WILL MONITOR TRENDS IN CASE
VISIBILITY REDUCTIONS BECOME LOW ENOUGH FOR A LONG ENOUGH TIME TO
REQUIRE A DENSE FOG ADVISORY...BUT RECENT HRRR SIMULATIONS SUGGEST
FOG WILL NOT BE AS PREVALENT AS LAST NIGHT AS MID- AND HIGH-LEVEL
CLOUD COVER INCREASES. OTHER THAN ADJUSTING THE FOG MENTION...FEW
CHANGES WERE MADE WITH THIS UPDATE.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 247 PM CST WED JAN 20 2016
MAIN CONCERNS THIS PERIOD WILL BE FOG THIS EVENING AND OVERNIGHT
THEN LIGHT SNOW TONIGHT AND THURSDAY.
FOG HAS BEEN SLOW TO LIFT ACROSS THE NORTHERN JAMES RIVER VALLEY
WITH VISIBILITIES AROUND ONE HALF MILE MUCH OF THE AFTERNOON. AS
MID/HIGH CLOUDS OVERSPREAD THE REGION EXPECT THE FOG TO GRADUALLY
IMPROVE INTO THE EVENING HOURS. BUFKIT SOUNDINGS SHOW LOW LEVEL
SATURATION OVER THE JAMESTOWN-BISMARCK-MINOT AREA SO HAVE KEPT FOG
IN THROUGH TONIGHT THIS AREA.
A BUILDING H500 RIDGE OVER THE WEST COAST THROUGH 36 HOURS WILL
NUDGE A WEAK SHORTWAVE DOWN THE EAST SIDE OF IN INTO THE NORTHERN
PLAINS AND WEAKLY IMPACT NORTH DAKOTA TONIGHT AND THURSDAY. TODAYS
DETERMINISTIC MODEL RUNS HAVE BEEN LESS ROBUST IN GENERATING
PRECIPITATION THAN PREVIOUS ONES. GENERALLY LOWERED POPS INTO THE
CHANCE CATEGORY TONIGHT AND THURSDAY. SNOW FALL TOTALS REMAIN BELOW
ONE INCH.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 247 PM CST WED JAN 20 2016
MAIN MESSAGE WILL BE THE BRIEF WARMING TREND SLATED FOR FRIDAY AND
SATURDAY. AN UPPER LEVEL RIDGE WILL SHIFT FROM THE NORTHERN ROCKIES
INTO THE NORTHERN HIGH PLAINS FRIDAY. THE RIDGE SHIFTS EAST SATURDAY
AS HEIGHTS FLATTEN IN RESPONSE TO A SHORTWAVE AND SURFACE LOW MOVING
ACROSS SOUTHERN CANADA. THE NAEFS (NORTH AMERICAN ENSEMBLE FORECAST
SYSTEM) SITUATION TABLE SHOWS H85-H7 TEMPS IN THE 90TH TO 97TH
PERCENTILE FRIDAY THROUGH SATURDAY. MAX 850MB TEMPS OF +6C TO +8C
WILL SLIDE ACROSS WESTERN AND CENTRAL NORTH DAKOTA DURING THIS TIME
PERIOD. HOWEVER...THE NAM/GFS BUFKIT SOUNDINGS ADVERTISE QUITE A BIT
OF LOW LEVEL MOISTURE TRAPPED UNDERNEATH THE WARMER TEMPERATURES
ALOFT/INVERSION FRIDAY...BUT NOT AS MUCH BY SATURDAY AFTERNOON.
THUS OTHER THAN FAR WESTERN NORTH DAKOTA FRIDAY...WE PROBABLY WILL
NOT BE ABLE TO REALIZE THE MAXIMUM WARMTH ALOFT/MIXING TO THE
SURFACE UNTIL SATURDAY...AS MORE SUNSHINE AND THE PASSAGE OF A
SURFACE TROUGH/PSEUDO COLD FRONT OCCURS. HIGHS FRIDAY WILL RANGE
FROM THE 20S CENTRAL TO MID AND UPPER 30S WEST. BY SATURDAY HIGHS OF
33F TO 43F ARE EXPECTED ACROSS WESTERN AND CENTRAL NORTH DAKOTA.
THE MAIN COLD FRONT AND MAXIMUM COLD AIR ADVECTION SLIDES THROUGH
SATURDAY NIGHT INTO SUNDAY. THIS WILL OCCUR IN CONJUNCTION WITH A
SHORTWAVE COMING IN FROM THE WEST RESULTING IN A CHANCE OF SNOW
SUNDAY AND POSSIBLY INTO MONDAY. THE GFS AND ECMWF ARE NOT IN
AGREEMENT WITH THE TIMING OF SNOW. THE GFS ADVERTISES A DRY SUNDAY
AND SOME SNOW MONDAY...WHILE THE ECMWF SHOWS CHANCES OF SNOW SUNDAY
BUT VERY LITTLE MONDAY. IT WOULD APPEAR THE SUPERBLEND IS IN FAVOR
OF THE ECMWF WITH SUNDAY/SUNDAY NIGHT BEING THE FAVORED TIME FOR
SNOW. COLDER TEMPERATURES WILL ENSUE SUNDAY THROUGH WEDNESDAY WITH
HIGHS MOSTLY IN THE 20S. THE WEATHER COULD A BIT MORE ACTIVE MIDWEEK
AND ONWARD AS A SERIES OF CLIPPERS ARE POSSIBLE...PER GFS AND
ECMWF.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 619 PM CST WED JAN 20 2016
WIDESPREAD IFR TO LIFR CONDITIONS IN LOW CLOUDS AND SOME FOG WILL
PREVAIL ACROSS MOST OF WESTERN AND CENTRAL ND TONIGHT AND THURSDAY
MORNING. LIGHT SNOW IS POSSIBLE OVER SOUTHWEST ND AS WELL AS WEAK
LOW PRESSURE CROSSES THE REGION. BY THURSDAY AFTERNOON...THERE MAY
BE SOME IMPROVEMENT IN CEILINGS...BUT CONFIDENCE IS LOW.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...CJS
SHORT TERM...WAA
LONG TERM...KS
AVIATION...CJS
AREA FORECAST DISCUSSION
NWS BISMARCK ND
236 PM CST TUE JAN 19 2016
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 229 PM CST TUE JAN 19 2016
LOOKS LIKE THE VERY COLD AIR WILL TAKE AN EXIT FOR AWHILE.
CONCERNS NOW FOR THIS SHORT TERM PERIOD WILL FOCUS ON THE
POTENTIAL FOR FOG TONIGHT. MESOSCALE MODELS HAVE BEEN CONSISTENTLY
FORECASTING A SHALLOW COOL AND MOIST BOUNDARY LAYER FREE OF
CLOUDS ABOVE. HRRR DEVELOPS WIDESPREAD LOW VISIBILITIES THIS
EVENING AND OVERNIGHT.
SATELLITE TRENDS SO FAR TODAY SHOW THE STRATUS LAYER ERODING
IN LOW LEVEL WARM ADVECTION ACROSS WESTERN NORTH DAKOTA. THIS
PROCESS WILL BE DISRUPTED THIS EVENING AS SUNSET APPROACHES.
DURING THE COOLING HOURS IN THE EVENING EXPECT FOG TO FORM IN THE
CLEARING ZONE WITH THE CLOUDS CREEPING BACK WEST. THIS WILL MAKE
MIN TEMPERATURES IN THE CLEARING AREA A CHALLENGE. SO FAR HAVE
ACCEPTED THE CONSSHORT GUIDANCE GIVING LOWER TEENS ACROSS THE
WEST AND SINGLE DIGITS ABOVE ZERO EAST.
ON WEDNESDAY THE NEXT SHORTWAVE IN A SERIES OF SHORTWAVES WILL
BRING AN INCREASE IN MID/HIGH CLOUDS AND BREAK OF THE BOUNDARY LAYER
FOG DURING FORENOON. A SLIGHT CHANCE OF SNOW SEEMS REASONABLE BY
LATE AFTERNOON FAR WEST. HIGH WEDNESDAY IN THE 20S TO MID 30S.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 229 PM CST TUE JAN 19 2016
WEDNESDAY NIGHT THROUGH THURSDAY...COLD AIR ADVECTION AND A CHANCE
OF LIGHT SNOW WILL BEGIN POURING INTO SOUTHWEST NORTH DAKOTA
WEDNESDAY EVENING AS A SURFACE LOW AND ASSOCIATED MID LEVEL
SHORTWAVE SCOOT FROM SOUTHEAST MONTANA INTO SOUTH DAKOTA. THIS WILL
BE FOLLOWED BY ANOTHER SHORTWAVE THURSDAY...AS IT MOVES FROM WEST TO
EAST DURING THE DAY. THERE HAD BEEN SOME CONCERN FOR LIGHT FREEZING
RAIN WEDNESDAY EVENING...BUT THE NAM/SREF/GFS BUFKIT SOUNDINGS
INDICATE THAT IF IT DID DEVELOP...IT WOULD BE BRIEF...WITH A FAIRLY
QUICK TRANSITION TO LIGHT SNOW. NOT SEEING AN EXTENDED PERIOD OF
UPWARD VERTICAL MOTION WITH WITHIN THE SUPERCOOLED WATER DROPLET
REGIME...AND THE TRANSITION TIME FOR ANY GIVEN SOUNDING TO REACH
COLDER/HIGHER LEVELS OF SATURATION IS ACHIEVED FAIRLY QUICKLY
WEDNESDAY NIGHT. THUS...GIVEN THE BRIEF TIME AND ISOLATED COVERAGE
OF LIGHT FREEZING RAIN POTENTIAL...HAVE DECIDED TO STICK WITH THE
GIVEN FORECAST WHICH KEEPS A MENTION OF ONLY LIGHT SNOW. WILL
REVISIT THE SOUNDINGS AGAIN TONIGHT AND WEDNESDAY FOR ANY
SIGNIFICANT CHANGES TO THE ABOVE THINKING. OTHERWISE...CHANCES FOR
LIGHT SNOW WILL EXPAND INTO CENTRAL NORTH DAKOTA THROUGH THE DAY
THURSDAY. SNOWFALL ACCUMULATIONS THROUGH THURSDAY EVENING ARE
FORECAST AROUND A HALF INCH WEST AND CENTRAL...WITH AN ISOLATED SPOT
OF ONE INCH IN THE SOUTHWEST. THE CHANCE OF LIGHT SNOW EXITS THE
SOUTHERN JAMES RIVER VALLEY THURSDAY EVENING. WITH ONGOING COLD AIR
ADVECTION...HIGH TEMPERATURES THURSDAY WILL BE 5 TO 10 DEGREES
COLDER FROM WEDNESDAY...WHICH PUTS HIGHS THURSDAY FROM AROUND 10F
ABOVE IN THE TURTLE MOUNTAINS TO 25F SOUTHWEST.
THURSDAY NIGHT THROUGH SATURDAY...FOLLOWING THE ABOVE SHORTWAVE IS
AN UPPER LEVEL RIDGE WHICH WILL SHIFT FROM THE NORTHERN ROCKIES INTO
THE NORTHERN HIGH PLAINS FRIDAY INTO MOST OF SATURDAY. STRONG LOW
LEVEL WARM AIR ADVECTION FRIDAY AND SATURDAY WILL RESULT IN A
MODERATING TREND ALONG WITH DRY CONDITIONS. HIGHS FRIDAY WILL RANGE
FROM AROUND 20 IN THE JAMES RIVER VALLEY TO 40 WEST. BY SATURDAY
HIGHS WILL RANGE BETWEEN 30F AND 40F ACROSS WESTERN AND CENTRAL
NORTH DAKOTA.
THE WARMING TREND WILL COME TO AN END SATURDAY EVENING...AS A COLD
FRONT SWEEPS FROM NORTHWEST TO SOUTHEAST. THIS LEADS TO A CHANCE OF
SNOW AND COLDER TEMPERATURES SUNDAY. HIGHS SUNDAY THROUGH TUESDAY
ARE NEARLY THE SAME EACH DAY WITH HIGHS IN THE UPPER TEENS IN THE
TURTLE MOUNTAINS TO 20S ELSEWHERE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 229 PM CST TUE JAN 19 2016
A WARM FRONT ACROSS WESTERN NORTH DAKOTA CLEARING CLOUDS FROM
KISN-KDIK EAST TO NEAR THE MISSOURI RIVER. MVFR TO IFR CONDITIONS
PERSIST CENTRAL(KMOT- KBIS- KJMS). LOW LEVEL MOIST BOUNDARY LAYER
WILL RETURN WESTWARD THIS EVENING. EXPECT LOW IFR CONDITIONS TO
DEVELOP IN FZFG KISN-KDIK AFTER 02Z AND IFR CONDITIONS IN BR
KISN-KMOT-KBIS-KJMS AS WELL.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...WAA
LONG TERM...KS
AVIATION...WAA
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
949 PM EST WED JAN 20 2016
.SYNOPSIS...
HIGH PRESSURE WILL BUILD ACROSS THE REGION TONIGHT AND THURSDAY
AND THEN SHIFT NORTHEAST THURSDAY NIGHT. LOW PRESSURE WILL THEN
TRACK EAST ACROSS THE SOUTHEASTERN UNITED STATES ALLOWING SNOW TO
MOVE INTO NORTHERN KENTUCKY AND SOUTHERN OHIO.
&&
.NEAR TERM /UNTIL THURSDAY AFTERNOON/...
NOT MANY CHANGES TO ONGOING FORECAST PACKAGE THIS EVENING. SKIES
HAVE STARTED TO CLEAR ACROSS DARKE AND MERCER COUNTIES ALREADY
ALLOWING TEMPERATURES TO FALL INTO THE SINGLE DIGITS. DID TREND
MIN TEMPS DOWN A BIT ACROSS THE AREA GIVEN CURRENT OBS. DURING THE
DAY THURSDAY SURFACE HIGH PRESSURE WILL REMAIN CENTERED JUST NORTH
OF THE AREA WITH 1000 MB TO 900 MB THICKNESSES BETWEEN 815 AND
820 M. THIS WOULD SUPPORT HIGHS IN THE MID TO UPPER 20S. GIVEN THE
CIRRUS SHIELD FORECASTED TO MOVE INTO THE AREA AND THE SNOW PACK
HAVE KEPT MAX TEMPS BELOW GUIDANCE FOR THURSDAY AFTERNOON. NO
OTHER CHANGES AT THIS TIME.
PREV DISCUSSION ->
HIGH PRESSURE OVER ILLINOIS WILL BUILD INTO THE REGION OVERNIGHT.
ALTHOUGH GUIDANCE IS SHOWING A SHALLOW LAYER OF LOW LEVEL MOISTURE
REMAINING...SUSPECT THAT IT IS THIN ENOUGH TO ALLOW CLEARING NOW
SEEN UNDER THE HIGH TO WORK ACROSS THE AREA. WITH LIGHT WINDS AND
FRESH SNOW COVER...EXPECT GOOD RADIATIONAL COOLING CONDITIONS. SO
HAVE UNDERCUT GUIDANCE FOR LOWS.
&&
.SHORT TERM / THURSDAY AFTERNOON THROUGH FRIDAY NIGHT/...
HIGH WILL REMAIN ACROSS THE NORTHERN PART OF THE FORECAST AREA
THURSDAY AND THEN MOVE OFF TO THE NORTHEAST THURSDAY EVENING. SOME
HIGH CLOUDS WILL STREAM ACROSS THE REGION. EXPECT COLD CONDITIONS
TO CONTINUE AND HAVE KEPT TEMPERATURES ON THE COOL SIDE OF
GUIDANCE.
LOW PRESSURE WILL STRENGTHEN AS IT MOVES INTO THE TENNESSEE
VALLEY FRIDAY. SNOW WILL SPREAD WELL NORTH OF THE LOW CENTER AND
MOVE INTO THE REGION THROUGH THE DAY. EXPECT GREATEST SNOWFALL TO
OCCUR DURING THE AFTERNOON AND EVENING. SOME LIGHT SNOW WILL
LINGER INTO LATE FRIDAY NIGHT AS THE LOW WEAKENS WEST OF THE
APPALACHIANS AND ENERGY TRANSFERS TO THE ATLANTIC COAST.
STILL A FAIR AMOUNT OF UNCERTAINTY WITH THE NORTHWARD EXTENT OF
THE SNOW. I-71 CORRIDOR SEEMS LIKE MEAN DIVIDING LINE. THERE IS
SOME CONVERGENCE IN MODEL SOLUTIONS TOWARDS HEAVIER PRECIPITATION
POTENTIAL FOR THE SOUTHEAST COUNTIES WHERE 4 INCHES OR MORE OF
SNOW IS POSSIBLE. SO HAVE INCLUDED THOSE LOCATIONS IN A WINTER
STORM WATCH. WILL LIKELY BE A PRETTY TIGHT GRADIENT BETWEEN THE
HEAVIER SNOW AND JUST LIGHT ACCUMULATIONS. AND WHERE THAT GRADIENT
SETS UP REMAINS IN FLUX.
FORECAST HIGHS FRIDAY ARE A BIT BELOW COOLER NAM MOS WHILE WARMER
GFS MOS SEEMS MORE REASONABLE FOR FRIDAY NIGHT LOWS.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
WINTER STORM WILL BE EXITING THE AREA ON SATURDAY. SOME ADDITIONAL
MINOR SNOW ACCUMULATIONS WILL BE POSSIBLE ACROSS SE PORTIONS OF THE
FA. H8 WINDS WILL BE OFF OF LAKE ERIE ON SATURDAY. ONLY THE SW
CORNER OF THE LAKE IS MOSTLY FROZEN OVER. WITH LONG FETCH OFF OF
THE LAKE THERE IS THE POTENTIAL FOR SOME LIGHT SNOW OR SNOW FLURRIES
ACROSS EXTREME NORTHERN PORTIONS OF THE FA. WINTER STORM AND LAKE
EFFECT SNOW WILL TAPER OFF BY SATURDAY EVENING HOWEVER SOME CLOUDS
WILL LINGER INTO PART OF THE OVERNIGHT HOURS ACROSS NE PORTIONS OF
THE FA.
WITH SKIES BECOMING MOSTLY CLEAR SATURDAY NIGHT TEMPERATURES WILL
DROP OFF PRETTY QUICKLY ESPECIALLY ACROSS SE PORTIONS OF THE FA
WHERE THERE WILL BE FRESH SNOW COVER. TEMPERATURES ARE EXPECTED TO
REBOUND INTO THE 30S ON SUNDAY WITH SOUTHERLY FLOW AND SUNSHINE.
THERE WILL BE AN INCREASE IN CLOUD COVER HOWEVER THROUGH THE DAY ON
SUNDAY IN ADVANCE OF THE NEXT SYSTEM.
THERE WILL BE A MIX OF RAIN AND SNOW ACROSS THE AREA ON MONDAY
BEFORE COLDER AIR WORKS IN AND TRANSITIONS OVER TO ALL SNOW MONDAY
NIGHT. WENT ON THE COOL SIDE OF GUIDANCE WITH THIS SYSTEM AND THE
QUICKER CHANGEOVER TO SNOW.
MULTIPLE WEAK DISTURBANCES WILL KEEP LOWER PRECIPITATION CHANCES IN
THE FORECAST FOR TUESDAY AND WEDNESDAY. TEMPERATURES WILL BE COLD
ENOUGH THAT ANY ADDITIONAL PRECIPITATION WILL BE IN THE FORM OF SNOW
SHOWERS.
&&
.AVIATION /03Z THURSDAY THROUGH MONDAY/...
ALL TAF SITES CURRENTLY MVFR WITH CLEARING OCCURRING OUT IN
ILLINOIS INTO INDIANA. LATEST RUN OF RAP SHOWING CLOUDS
SCATTERING OUT BY EARLY THURSDAY MORNING. GLOBAL MODELS DO
DISAGREE ON WHEN AND IF THE MVFR DECK EVEN SCATTERS OUT THURSDAY.
THE NAM CONTINUES TO BE MORE PESSIMISTIC WHILE THE GFS HAS TAF
SITES GOING VFR THURSDAY MORNING LIKE THE RAP. HAVE KEPT FORECAST
FAVORING THE RAP/ GFS SOLUTION. SURFACE HIGH PRESSURE WILL START
TO MOVE OVER THE AREA THURSDAY MORNING ALLOWING FOR WINDS TO
REMAIN LIGHT. SURFACE HIGH PRESSURE WILL THEN START TO GET
SQUEEZED NORTH AS THE NEXT SYSTEM APPROACHES FROM THE SOUTH. THIS
WILL KEEP WINDS MAINLY OUT OF THE EAST. ONCE MVFR CLOUDS BREAK
THURSDAY MORNING VFR CONDITIONS ARE EXPECTED THROUGH THE ISSUANCE.
OUTLOOK...MVFR/IFR CONDITIONS ARE EXPECTED WITH PRECIPITATION FRIDAY
INTO SATURDAY AND THEN AGAIN LATE MONDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...WINTER STORM WATCH FROM LATE THURSDAY NIGHT THROUGH SATURDAY
MORNING FOR OHZ079-081-082-088.
KY...WINTER STORM WATCH FROM LATE THURSDAY NIGHT THROUGH SATURDAY
MORNING FOR KYZ094>100.
IN...NONE.
&&
$$
SYNOPSIS...KC/HAINES
NEAR TERM...KC/HAINES
SHORT TERM...
LONG TERM...NOVAK
AVIATION...KC/HAINES
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
639 PM EST WED JAN 20 2016
.SYNOPSIS...
HIGH PRESSURE WILL BUILD ACROSS THE REGION TONIGHT AND THURSDAY
AND THEN SHIFT NORTHEAST THURSDAY NIGHT. LOW PRESSURE WILL TRACK
FROM THE LOWER MISSISSIPPI VALLEY INTO THE TENNESSEE VALLEY
THURSDAY NIGHT THROUGH FRIDAY NIGHT WHICH WILL SPREAD SNOW ACROSS
THE REGION.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
HIGH PRESSURE OVER ILLINOIS WILL BUILD INTO THE REGION OVERNIGHT.
ALTHOUGH GUIDANCE IS SHOWING A SHALLOW LAYER OF LOW LEVEL MOISTURE
REMAINING...SUSPECT THAT IT IS THIN ENOUGH TO ALLOW CLEARING NOW
SEEN UNDER THE HIGH TO WORK ACROSS THE AREA. WITH LIGHT WINDS AND
FRESH SNOW COVER...EXPECT GOOD RADIATIONAL COOLING CONDITIONS. SO
HAVE UNDERCUT GUIDANCE FOR LOWS.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
HIGH WILL REMAIN ACROSS THE NORTHERN PART OF THE FORECAST AREA
THURSDAY AND THEN MOVE OFF TO THE NORTHEAST THURSDAY EVENING. SOME
HIGH CLOUDS WILL STREAM ACROSS THE REGION. EXPECT COLD CONDITIONS
TO CONTINUE AND HAVE KEPT TEMPERATURES ON THE COOL SIDE OF
GUIDANCE.
LOW PRESSURE WILL STRENGTHEN AS IT MOVES INTO THE TENNESSEE
VALLEY FRIDAY. SNOW WILL SPREAD WELL NORTH OF THE LOW CENTER AND
MOVE INTO THE REGION THROUGH THE DAY. EXPECT GREATEST SNOWFALL TO
OCCUR DURING THE AFTERNOON AND EVENING. SOME LIGHT SNOW WILL
LINGER INTO LATE FRIDAY NIGHT AS THE LOW WEAKENS WEST OF THE
APPALACHIANS AND ENERGY TRANSFERS TO THE ATLANTIC COAST.
STILL A FAIR AMOUNT OF UNCERTAINTY WITH THE NORTHWARD EXTENT OF
THE SNOW. I-71 CORRIDOR SEEMS LIKE MEAN DIVIDING LINE. THERE IS
SOME CONVERGENCE IN MODEL SOLUTIONS TOWARDS HEAVIER PRECIPITATION
POTENTIAL FOR THE SOUTHEAST COUNTIES WHERE 4 INCHES OR MORE OF
SNOW IS POSSIBLE. SO HAVE INCLUDED THOSE LOCATIONS IN A WINTER
STORM WATCH. WILL LIKELY BE A PRETTY TIGHT GRADIENT BETWEEN THE
HEAVIER SNOW AND JUST LIGHT ACCUMULATIONS. AND WHERE THAT GRADIENT
SETS UP REMAINS IN FLUX.
FORECAST HIGHS FRIDAY ARE A BIT BELOW COOLER NAM MOS WHILE WARMER
GFS MOS SEEMS MORE REASONABLE FOR FRIDAY NIGHT LOWS.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
WINTER STORM WILL BE EXITING THE AREA ON SATURDAY. SOME ADDITIONAL
MINOR SNOW ACCUMULATIONS WILL BE POSSIBLE ACROSS SE PORTIONS OF THE
FA. H8 WINDS WILL BE OFF OF LAKE ERIE ON SATURDAY. ONLY THE SW
CORNER OF THE LAKE IS MOSTLY FROZEN OVER. WITH LONG FETCH OFF OF
THE LAKE THERE IS THE POTENTIAL FOR SOME LIGHT SNOW OR SNOW FLURRIES
ACROSS EXTREME NORTHERN PORTIONS OF THE FA. WINTER STORM AND LAKE
EFFECT SNOW WILL TAPER OFF BY SATURDAY EVENING HOWEVER SOME CLOUDS
WILL LINGER INTO PART OF THE OVERNIGHT HOURS ACROSS NE PORTIONS OF
THE FA.
WITH SKIES BECOMING MOSTLY CLEAR SATURDAY NIGHT TEMPERATURES WILL
DROP OFF PRETTY QUICKLY ESPECIALLY ACROSS SE PORTIONS OF THE FA
WHERE THERE WILL BE FRESH SNOW COVER. TEMPERATURES ARE EXPECTED TO
REBOUND INTO THE 30S ON SUNDAY WITH SOUTHERLY FLOW AND SUNSHINE.
THERE WILL BE AN INCREASE IN CLOUD COVER HOWEVER THROUGH THE DAY ON
SUNDAY IN ADVANCE OF THE NEXT SYSTEM.
THERE WILL BE A MIX OF RAIN AND SNOW ACROSS THE AREA ON MONDAY
BEFORE COLDER AIR WORKS IN AND TRANSITIONS OVER TO ALL SNOW MONDAY
NIGHT. WENT ON THE COOL SIDE OF GUIDANCE WITH THIS SYSTEM AND THE
QUICKER CHANGEOVER TO SNOW.
MULTIPLE WEAK DISTURBANCES WILL KEEP LOWER PRECIPITATION CHANCES IN
THE FORECAST FOR TUESDAY AND WEDNESDAY. TEMPERATURES WILL BE COLD
ENOUGH THAT ANY ADDITIONAL PRECIPITATION WILL BE IN THE FORM OF SNOW
SHOWERS.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
ALL TAF SITES CURRENTLY MVFR WITH CLEARING OCCURRING OUT IN
ILLINOIS INTO INDIANA. LATEST RUN OF RAP SHOWING CLOUDS
SCATTERING OUT BY EARLY THURSDAY MORNING. GLOBAL MODELS DO
DISAGREE ON WHEN AND IF THE MVFR DECK EVEN SCATTERS OUT THURSDAY.
THE NAM CONTINUES TO BE MORE PESSIMISTIC WHILE THE GFS HAS TAF
SITES GOING VFR THURSDAY MORNING LIKE THE RAP. HAVE KEPT FORECAST
FAVORING THE RAP/ GFS SOLUTION. SURFACE HIGH PRESSURE WILL START
TO MOVE OVER THE AREA THURSDAY MORNING ALLOWING FOR WINDS TO
REMAIN LIGHT. SURFACE HIGH PRESSURE WILL THEN START TO GET
SQUEEZED NORTH AS THE NEXT SYSTEM APPROACHES FROM THE SOUTH. THIS
WILL KEEP WINDS MAINLY OUT OF THE EAST. ONCE MVFR CLOUDS BREAK
THURSDAY MORNING VFR CONDITIONS ARE EXPECTED THROUGH THE ISSUANCE.
OUTLOOK...MVFR/IFR CONDITIONS ARE EXPECTED WITH PRECIPITATION FRIDAY
INTO SATURDAY AND THEN AGAIN LATE MONDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...WINTER STORM WATCH FROM LATE THURSDAY NIGHT THROUGH SATURDAY
MORNING FOR OHZ079-081-082-088.
KY...WINTER STORM WATCH FROM LATE THURSDAY NIGHT THROUGH SATURDAY
MORNING FOR KYZ094>100.
IN...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...
LONG TERM...NOVAK
AVIATION...HAINES/CASSADY
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
1245 PM EST TUE JAN 19 2016
.SYNOPSIS...
COLD CONTINUES TODAY AND TONIGHT UNDER HIGH PRESSURE AND LIGHTER WINDS.
WEAKENING SYSTEM WEDNESDAY COULD LEAVE MINOR SNOW ACCUMULATIONS. A
MAJOR WINTER STORM DEVELOPS THURSDAY NIGHT AND LINGERS INTO SATURDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
930 AM UPDATE...
CLOUDS SLOW TO ERODE...BUT ARE IN FACT DOING SO AT THIS HOUR...AND
SHOULD BE CLEARING AS WE HEAD INTO THE AFTERNOON HOURS TODAY. SENT
SOME REVAMPED SKY COVER GRIDS...AND WILL KEEP THE FLURRIES OUT AS
OBSERVATIONS WITH SNOW/FLURRIES ARE COMING FEW AND FAR BETWEEN.
PREVIOUS DISCUSSION BELOW...
PESKY STRATOCU HOLDING STRONG IN THE MOUNTAINS WITH SCT FLURRIES
OR ICE CRYSTALS FALLING. OUTSIDE OF THAT...A PASSING S/W TROF MAY
BRING SOME CLOUDS INTO THE AREA THRU MORNING...ESPECIALLY ACROSS
NE KY/S WV/ AND SW VA WHERE A PASSING FLURRY CANNOT BE RULED OUT.
HIGH PRESSURE BUILDS INTO THE REGION TODAY WHICH WILL FURTHER
DIMINISH THE WIND. STILL COULD SEE SOME GUSTS IN THE N MOUNTAINS
THOUGH. HI RES MODELS TRYING TO SHOW SOME AFTERNOON STREAKY STRATOCU
DEVELOPING OVER SE OH AND N WV AGAIN TODAY. BUMPED SKY COVER UP A
BIT THERE BUT NOT TO THE DEGREE THE HRRR WOULD SUGGEST. TEMPS TODAY
SHOULD RECOVER ABOUT 5 DEGREES FROM YESTERDAY BUT STILL COLD
OVERALL.
WITH HIGH PRESSURE OVERHEAD TONIGHT...EXPECTING A QUICK FALL IN
TEMPS THIS EVENING...ESPECIALLY OVER AREAS THAT HAVE SNOW ON THE
GROUND. HOWEVER...MID AND HI CLOUDS WILL BE ADVANCING TOWARD THE
AREA LATE WHICH WILL CAP THE FREE FALL. WAA ALOFT WILL ALSO COMMENCE
WHICH SHOULD ALLOW THE HIGHER ELEVATIONS TO SEE A SLOW RISE
OVERNIGHT.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
THE WEAKENING SUPPORT/LIFT ON WEDNESDAY WILL WORK HARD TO SATURATE THE COLUMN
IN THE INITIALLY DRY ARCTIC AIR.
FEATURE IS A COMBO OF A 500 MB TROF AND WARM AIR ADVECTION IN THE LOW LEVELS.
FOR EXAMPLE...THE 850 MB FLOW OF 30 TO 40 KNOTS IS PERPENDICULAR TO THE
850 MB ISOTHERMS VCNTY STL TUESDAY EVENING. BY 18Z WEDNESDAY...THE FLOW
IS ALMOST PARALLEL TO THE ISOTHERMS. NOT MUCH CHANGE TO OUR 1 TO 2 INCH
FORECAST...BUT DID TRY TO DAMPEN THE NORTHERN COUNTIES...INCLUDING THE
ROUTE 50 CORRIDOR TO MOSTLY AN INCH OR LESS OF SNOW ACCUMULATION ON
WEDNESDAY.
MEANWHILE...TRIED TO BOOST PORTIONS OF NORTHEAST KENTUCKY...THE SOUTHERN
COAL FIELDS OF WEST VIRGINIA...BUCHANAN AND DICKENSON COUNTIES IN VIRGINIA
MORE TOWARD THE 2 INCH ACCUMULATION. IF SYSTEM DOES NOT DAMPEN QUICKER
THAN EXPECTED...WINTER WX ADVISORIES WILL LIKELY BE POSTED IN SOME COUNTIES
THAT HAVE THE 2 INCH CRITERIA...WHICH IS THE SAME THEME AS YESTERDAY.
WILL CUT BACK ON HIGH TEMPERATURES IN THE SOUTHWEST ON WEDNESDAY...WHERE
THE SNOW WILL LIKELY REACH THE GROUND IN THE MORNING.
WEDNESDAY SYSTEM LEAVES THE LOW ELEVATIONS SATURATED...COULD NOT COMPLETELY
RULE OUT SOME FREEZING DRIZZLE IN THE MOUNTAINS OR SOUTHERN COUNTIES OVERNIGHT
WEDNESDAY NIGHT IN THE WAKE OF THE SYNOPTIC LIGHT SNOW. YET...WILL NOT INSERT
YET INTO THE FORECAST. NORTHERN COUNTIES HAVE A BETTER CHANCE OF THE
LOWER CLOUDS BREAKING UP BEFORE DAWN THURSDAY.
WILL SLOW DOWN THE INCREASING POPS LATE THURSDAY IN THE EXTREME SOUTH A
FEW HOURS.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
ON THE MIDNIGHT SHIFT THIS TUESDAY MORNING...NO REASON TO MAKE MAJOR CHANGES
TO OUR GRIDS FOR THE MAJOR STORM. AS WE KNOW...MAJOR ADJUSTMENTS ARE WISER
AS WE GET CLOSER...INSTEAD OF SEESAWING DAYS AWAY.
WITH THE MID LEVEL AND 850 MB LOW STILL TO OUR WEST ON FRIDAY...AND A STRONG
SOUTHERLY 40 KNOT 850 MB FLOW INTO SOUTHERN WEST VIRGINIA...WE STILL LIKE
THE FORECAST RAIN WORKING NORTH OVERNIGHT THURSDAY NIGHT INTO FRIDAY
FOR SOUTHERN COUNTIES. WILL NOT ADD A WATER HAZARD AS OF YET...BUT
AGAIN...EVEN THAT COULD NOT BE COMPLETELY RULED OUT FOR SOUTHERN
COUNTIES.
HOW FAR AND QUICKLY THAT WINTRY MIX WORKS NORTH...IS THE QUESTION.
WITH SOME SE COMPONENT THOUGH IN POCAHONTAS COUNTY...WE STILL LIKE
KEEPING MOSTLY SNOW IN POCAHONTAS COUNTY.
00Z ECMWF STILL A BIT FURTHER SOUTH WITH THE MID LEVEL AND 850 MB LOW
CIRCULATION...AND THUS A BIT COLDER AT CRITICAL 850 MB LEVEL.
DID INCREASE POPS FRIDAY NIGHT INTO SATURDAY MORNING IN THE STRONG WRAP
AROUND FROM THE DEEPENING STORM TO OUR EAST.
REST OF THIS LONG TERM IS FROM OUR LATE MONDAY PACKAGE...
MODELS AGREE ON THE POTENTIAL FOR A MAJOR WINTER WEATHER SYSTEM
IMPACTING THE AREA EARLY IN THE PERIOD.
A MIDSTREAM UPPER LEVEL S/W TROUGH DIGS SEWD THROUGH THE SRN
PLAINS STATES THU...TOWARD A L/W TROUGH POSITION E OF THE
MISSISSIPPI RIVER...WITH A RIDGE BUILDING TO ITS W. THE S/W
TROUGH CLOSES OFF FRI...TRACKS ACROSS THE SRN APPALACHIANS FRI
NT...AND THEN MEANDERS UP ALONG THE ERN SEABOARD ON SAT.
THE INITIAL SFC LOW CENTER TRACKS NEWD INTO SE KY AND SW VA THU
EVENING...WITH THE INVERTED LOW LEVEL TROUGH EXTENDING NWD UP
ALONG THE OHIO RIVER...PEAKING THE WARM WEDGE EFFECT AT THAT TIME.
THAT CENTER THEN FILLS OVERNIGHT AS THE NEW LOW CENTER GETS GOING
ALONG THE EASTERN SEABOARD. THAT CENTER SLOWLY MEANDERS UP THE
EASTERN SEABOARD SAT AND SAT NT...BEFORE FINALLY PULLING OUT TO
SEA ON SUNDAY.
THIS SCENARIO IS LIKELY TO RESULT IN SNOW OVERSPREADING THE AREA
FROM S TO N THU NT...WITH A TRANSITION TO SLEET AND THEN RAIN
INTO CENTRAL PORTIONS OF THE FCST AREA FROM THE S. FREEZING RAIN
IS ALSO POSSIBLE IN THE TRANSITION. THE HIGHEST LOW LEVEL
TEMPERATURES WILL OCCUR IN THE WARM WEDGE BETWEEN THE OHIO RIVER
AND THE WV MOUNTAINS. SFC TEMPERATURES SHOULD PEAK MID TO LATE
AFTERNOON FRI...BUT THE WARM WEDGE ALOFT STARTS PUSHING EWD LATE
FRI AFTERNOON. THIS COMBINATION KEEPS THE FREEZING RAIN POTENTIAL
IN THE MORNING AND MIDDAY FRI...MAINLY FOR SRN PORTIONS OF THE
AREA AND ALONG THE ERN SLOPES OF THE SRN WV MOUNTAINS.
ACCUMULATIONS THU NT AS LIKELY TO BE LIMITED OVER THE SRN COAL
FIELDS OF WV ON ACCOUNT OF SFC TEMPERATURES THERE GETTING ABOVE
FREEZING SOON AFTER THE ONSET OF THE PRECIPITATION. AN INCH OR
TWO ARE POSSIBLE ELSEWHERE BY DAWN FRI...DEPENDING UPON HOW
QUICKLY SLEET MIXES IN RELATIVE TO THE ONSET TIME OF THE
PRECIPITATION. THE CENTRAL MOUNTAINS APPEAR MOST LIKELY TO GET
SEVERAL INCHES BY DAWN FRI AS THAT IS WHERE THERE IS LIKELY TO BE
THE MOST TIME BETWEEN THE ONSET OF THE PRECIPITATION AND THE
ARRIVAL OF ABOVE FREEZING TEMPERATURES ALOFT.
AS THE UPPER LEVEL LOW ROLLS S OF THE AREA FRI NT...THE LOW LEVEL
INVERTED TROUGH AND WARM WEDGE COLLAPSE...AND TEMPERATURES FALL
BELOW FREEZING THROUGHOUT THE COLUMN THROUGHOUT THE FCST AREA.
SNOW ACCUMULATIONS WILL DEPEND UPON THE PROGRESS OF THE WARM
WEDGE ON FRI...AND THEN HOW MUCH FORCING / DEFORMATION EXISTS OVER
THE AREA FRI NT AS THE COLD AIR SETTLES IN.
THE AIR MASS BEHIND THIS SYSTEM WILL ACTUALLY BE OF PACIFIC ORIGIN
AND THUS BE ONLY SEASONABLY CHILLY...AND THE NEXT WARM ADVECTION
SYSTEM NEXT MON BRINGS THE CHANCE FOR A LIGHT SNOW TO RAIN
TRANSITION.
WPC TEMPERATURES LOOKED REASONABLE AND WERE GENERALLY BLENDED IN.
HAVE TEMPERATURES RISING TOWARD DAWN FRI WITH THE WARM WEDGE
EFFECT BEGINNING TO TAKE HOLD...USED GFS BASED TEMPERATURES IN
ADDITION TO WPC DURING THE STORM...THU NT INTO SAT.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
STILL HAVING TROUBLE GETTING THE STRATOCU TO DISSIPATE...BUT NOW
SEEING A FEW BREAKS IN THAT DECK HERE AND THERE. CARRY THE MVFR
CEILINGS AT LOCATIONS FOR ANOTHER HOUR OR TWO...AND IT SHOULD
LIFT SLIGHTLY TO ABOVE VFR AT THAT TIME.
NEXT SYSTEM MAKES ITS APPEARANCE IN TERMS OF HIGH LEVEL CIRRUS
AFTER 03Z WEDNESDAY...WITH STEADILY LOWERING CEILINGS THROUGH THE
DAY ON WEDNESDAY. BY 18Z...MVFR HEIGHTS REACH THE TUG FORK
VALLEY...BUT WILL NOT PUT ANY MVFR IN THE TAFS BY THE END OF THE
18Z WEDNESDAY TIME FRAME.
SURFACE WINDS DECREASE AND TURN INTO LIGHT AND VARIABLE THIS
EVENING AND TONIGHT AS HIGH PRESSURE PASSES OVER THE AREA.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z WEDNESDAY...
FORECAST CONFIDENCE...HIGH
ALTERNATE SCENARIOS: NONE
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 15 16 17 18 19 20 21 22 23 00 01 02
EST 1HRLY 10 11 12 13 14 15 16 17 18 19 20 21
CRW CONSISTENCY M M H H H H H H H H H H
HTS CONSISTENCY H H H H H H H H H H H H
BKW CONSISTENCY M M H H H H H H H H H H
EKN CONSISTENCY M M M M M M M M H H H H
PKB CONSISTENCY H H M M M M M M H H H H
CKB CONSISTENCY M M M M M M M M H H H H
AFTER 18Z WEDNESDAY...
UPPER AIR DISTURBANCE WEDNESDAY/WEDNESDAY NIGHT COULD BRING LIGHT SNOW
WITH IFR.
WIDESPREAD IFR LIKELY WITH A WINTER STORM SYSTEM THURSDAY NIGHT
INTO SATURDAY.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...KTB/30
NEAR TERM...30/26
SHORT TERM...KTB
LONG TERM...TRM
AVIATION...26
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
919 AM EST TUE JAN 19 2016
.SYNOPSIS...
COLD CONTINUES TODAY AND TONIGHT UNDER HIGH PRESSURE AND LIGHTER WINDS.
WEAKENING SYSTEM WEDNESDAY COULD LEAVE MINOR SNOW ACCUMULATIONS. A
MAJOR WINTER STORM DEVELOPS THURSDAY NIGHT AND LINGERS INTO SATURDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
930 AM UPDATE...
CLOUDS SLOW TO ERODE...BUT ARE IN FACT DOING SO AT THIS HOUR...AND
SHOULD BE CLEARING AS WE HEAD INTO THE AFTERNOON HOURS TODAY. SENT
SOME REVAMPED SKY COVER GRIDS...AND WILL KEEP THE FLURRIES OUT AS
OBSERVATIONS WITH SNOW/FLURRIES ARE COMING FEW AND FAR BETWEEN.
PREVIOUS DISCUSSION BELOW...
PESKY STRATOCU HOLDING STRONG IN THE MOUNTAINS WITH SCT FLURRIES
OR ICE CRYSTALS FALLING. OUTSIDE OF THAT...A PASSING S/W TROF MAY
BRING SOME CLOUDS INTO THE AREA THRU MORNING...ESPECIALLY ACROSS
NE KY/S WV/ AND SW VA WHERE A PASSING FLURRY CANNOT BE RULED OUT.
HIGH PRESSURE BUILDS INTO THE REGION TODAY WHICH WILL FURTHER
DIMINISH THE WIND. STILL COULD SEE SOME GUSTS IN THE N MOUNTAINS
THOUGH. HI RES MODELS TRYING TO SHOW SOME AFTERNOON STREAKY STRATOCU
DEVELOPING OVER SE OH AND N WV AGAIN TODAY. BUMPED SKY COVER UP A
BIT THERE BUT NOT TO THE DEGREE THE HRRR WOULD SUGGEST. TEMPS TODAY
SHOULD RECOVER ABOUT 5 DEGREES FROM YESTERDAY BUT STILL COLD
OVERALL.
WITH HIGH PRESSURE OVERHEAD TONIGHT...EXPECTING A QUICK FALL IN
TEMPS THIS EVENING...ESPECIALLY OVER AREAS THAT HAVE SNOW ON THE
GROUND. HOWEVER...MID AND HI CLOUDS WILL BE ADVANCING TOWARD THE
AREA LATE WHICH WILL CAP THE FREE FALL. WAA ALOFT WILL ALSO COMMENCE
WHICH SHOULD ALLOW THE HIGHER ELEVATIONS TO SEE A SLOW RISE
OVERNIGHT.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
THE WEAKENING SUPPORT/LIFT ON WEDNESDAY WILL WORK HARD TO SATURATE THE COLUMN
IN THE INITIALLY DRY ARCTIC AIR.
FEATURE IS A COMBO OF A 500 MB TROF AND WARM AIR ADVECTION IN THE LOW LEVELS.
FOR EXAMPLE...THE 850 MB FLOW OF 30 TO 40 KNOTS IS PERPENDICULAR TO THE
850 MB ISOTHERMS VCNTY STL TUESDAY EVENING. BY 18Z WEDNESDAY...THE FLOW
IS ALMOST PARALLEL TO THE ISOTHERMS. NOT MUCH CHANGE TO OUR 1 TO 2 INCH
FORECAST...BUT DID TRY TO DAMPEN THE NORTHERN COUNTIES...INCLUDING THE
ROUTE 50 CORRIDOR TO MOSTLY AN INCH OR LESS OF SNOW ACCUMULATION ON
WEDNESDAY.
MEANWHILE...TRIED TO BOOST PORTIONS OF NORTHEAST KENTUCKY...THE SOUTHERN
COAL FIELDS OF WEST VIRGINIA...BUCHANAN AND DICKENSON COUNTIES IN VIRGINIA
MORE TOWARD THE 2 INCH ACCUMULATION. IF SYSTEM DOES NOT DAMPEN QUICKER
THAN EXPECTED...WINTER WX ADVISORIES WILL LIKELY BE POSTED IN SOME COUNTIES
THAT HAVE THE 2 INCH CRITERIA...WHICH IS THE SAME THEME AS YESTERDAY.
WILL CUT BACK ON HIGH TEMPERATURES IN THE SOUTHWEST ON WEDNESDAY...WHERE
THE SNOW WILL LIKELY REACH THE GROUND IN THE MORNING.
WEDNESDAY SYSTEM LEAVES THE LOW ELEVATIONS SATURATED...COULD NOT COMPLETELY
RULE OUT SOME FREEZING DRIZZLE IN THE MOUNTAINS OR SOUTHERN COUNTIES OVERNIGHT
WEDNESDAY NIGHT IN THE WAKE OF THE SYNOPTIC LIGHT SNOW. YET...WILL NOT INSERT
YET INTO THE FORECAST. NORTHERN COUNTIES HAVE A BETTER CHANCE OF THE
LOWER CLOUDS BREAKING UP BEFORE DAWN THURSDAY.
WILL SLOW DOWN THE INCREASING POPS LATE THURSDAY IN THE EXTREME SOUTH A
FEW HOURS.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
ON THE MIDNIGHT SHIFT THIS TUESDAY MORNING...NO REASON TO MAKE MAJOR CHANGES
TO OUR GRIDS FOR THE MAJOR STORM. AS WE KNOW...MAJOR ADJUSTMENTS ARE WISER
AS WE GET CLOSER...INSTEAD OF SEESAWING DAYS AWAY.
WITH THE MID LEVEL AND 850 MB LOW STILL TO OUR WEST ON FRIDAY...AND A STRONG
SOUTHERLY 40 KNOT 850 MB FLOW INTO SOUTHERN WEST VIRGINIA...WE STILL LIKE
THE FORECAST RAIN WORKING NORTH OVERNIGHT THURSDAY NIGHT INTO FRIDAY
FOR SOUTHERN COUNTIES. WILL NOT ADD A WATER HAZARD AS OF YET...BUT
AGAIN...EVEN THAT COULD NOT BE COMPLETELY RULED OUT FOR SOUTHERN
COUNTIES.
HOW FAR AND QUICKLY THAT WINTRY MIX WORKS NORTH...IS THE QUESTION.
WITH SOME SE COMPONENT THOUGH IN POCAHONTAS COUNTY...WE STILL LIKE
KEEPING MOSTLY SNOW IN POCAHONTAS COUNTY.
00Z ECMWF STILL A BIT FURTHER SOUTH WITH THE MID LEVEL AND 850 MB LOW
CIRCULATION...AND THUS A BIT COLDER AT CRITICAL 850 MB LEVEL.
DID INCREASE POPS FRIDAY NIGHT INTO SATURDAY MORNING IN THE STRONG WRAP
AROUND FROM THE DEEPENING STORM TO OUR EAST.
REST OF THIS LONG TERM IS FROM OUR LATE MONDAY PACKAGE...
MODELS AGREE ON THE POTENTIAL FOR A MAJOR WINTER WEATHER SYSTEM
IMPACTING THE AREA EARLY IN THE PERIOD.
A MIDSTREAM UPPER LEVEL S/W TROUGH DIGS SEWD THROUGH THE SRN
PLAINS STATES THU...TOWARD A L/W TROUGH POSITION E OF THE
MISSISSIPPI RIVER...WITH A RIDGE BUILDING TO ITS W. THE S/W
TROUGH CLOSES OFF FRI...TRACKS ACROSS THE SRN APPALACHIANS FRI
NT...AND THEN MEANDERS UP ALONG THE ERN SEABOARD ON SAT.
THE INITIAL SFC LOW CENTER TRACKS NEWD INTO SE KY AND SW VA THU
EVENING...WITH THE INVERTED LOW LEVEL TROUGH EXTENDING NWD UP
ALONG THE OHIO RIVER...PEAKING THE WARM WEDGE EFFECT AT THAT TIME.
THAT CENTER THEN FILLS OVERNIGHT AS THE NEW LOW CENTER GETS GOING
ALONG THE EASTERN SEABOARD. THAT CENTER SLOWLY MEANDERS UP THE
EASTERN SEABOARD SAT AND SAT NT...BEFORE FINALLY PULLING OUT TO
SEA ON SUNDAY.
THIS SCENARIO IS LIKELY TO RESULT IN SNOW OVERSPREADING THE AREA
FROM S TO N THU NT...WITH A TRANSITION TO SLEET AND THEN RAIN
INTO CENTRAL PORTIONS OF THE FCST AREA FROM THE S. FREEZING RAIN
IS ALSO POSSIBLE IN THE TRANSITION. THE HIGHEST LOW LEVEL
TEMPERATURES WILL OCCUR IN THE WARM WEDGE BETWEEN THE OHIO RIVER
AND THE WV MOUNTAINS. SFC TEMPERATURES SHOULD PEAK MID TO LATE
AFTERNOON FRI...BUT THE WARM WEDGE ALOFT STARTS PUSHING EWD LATE
FRI AFTERNOON. THIS COMBINATION KEEPS THE FREEZING RAIN POTENTIAL
IN THE MORNING AND MIDDAY FRI...MAINLY FOR SRN PORTIONS OF THE
AREA AND ALONG THE ERN SLOPES OF THE SRN WV MOUNTAINS.
ACCUMULATIONS THU NT AS LIKELY TO BE LIMITED OVER THE SRN COAL
FIELDS OF WV ON ACCOUNT OF SFC TEMPERATURES THERE GETTING ABOVE
FREEZING SOON AFTER THE ONSET OF THE PRECIPITATION. AN INCH OR
TWO ARE POSSIBLE ELSEWHERE BY DAWN FRI...DEPENDING UPON HOW
QUICKLY SLEET MIXES IN RELATIVE TO THE ONSET TIME OF THE
PRECIPITATION. THE CENTRAL MOUNTAINS APPEAR MOST LIKELY TO GET
SEVERAL INCHES BY DAWN FRI AS THAT IS WHERE THERE IS LIKELY TO BE
THE MOST TIME BETWEEN THE ONSET OF THE PRECIPITATION AND THE
ARRIVAL OF ABOVE FREEZING TEMPERATURES ALOFT.
AS THE UPPER LEVEL LOW ROLLS S OF THE AREA FRI NT...THE LOW LEVEL
INVERTED TROUGH AND WARM WEDGE COLLAPSE...AND TEMPERATURES FALL
BELOW FREEZING THROUGHOUT THE COLUMN THROUGHOUT THE FCST AREA.
SNOW ACCUMULATIONS WILL DEPEND UPON THE PROGRESS OF THE WARM
WEDGE ON FRI...AND THEN HOW MUCH FORCING / DEFORMATION EXISTS OVER
THE AREA FRI NT AS THE COLD AIR SETTLES IN.
THE AIR MASS BEHIND THIS SYSTEM WILL ACTUALLY BE OF PACIFIC ORIGIN
AND THUS BE ONLY SEASONABLY CHILLY...AND THE NEXT WARM ADVECTION
SYSTEM NEXT MON BRINGS THE CHANCE FOR A LIGHT SNOW TO RAIN
TRANSITION.
WPC TEMPERATURES LOOKED REASONABLE AND WERE GENERALLY BLENDED IN.
HAVE TEMPERATURES RISING TOWARD DAWN FRI WITH THE WARM WEDGE
EFFECT BEGINNING TO TAKE HOLD...USED GFS BASED TEMPERATURES IN
ADDITION TO WPC DURING THE STORM...THU NT INTO SAT.
&&
.AVIATION /14Z TUESDAY THROUGH SATURDAY/...
AREAS OF MVFR STRATOCU THIS MORNING ALONG WITH SOME FLURRIES AND
ICE CRYSTALS EXPECTED THROUGH AROUND 15Z ACROSS S TERMINALS AND
MOUNTAIN TERMINALS.
AFTERNOON MVFR STRATOCU MAY REDEVELOP AGAIN ACROSS SE OH AND N
WV...AFFECTING KPKB/KCKB/KEKN WITH A PERIOD OF BKN MVFR CIGS.
MID AND HI CLOUDS ADVANCE INTO THE AREA FROM THE W TONIGHT AS ANY
REMAINING STRATOCU DISSIPATES.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z WEDNESDAY...
FORECAST CONFIDENCE...HIGH
ALTERNATE SCENARIOS: NONE
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 12 13 14 15 16 17 18 19 20 21 22 23
EST 1HRLY 07 08 09 10 11 12 13 14 15 16 17 18
CRW CONSISTENCY M M M M M H H H H H H H
HTS CONSISTENCY M M M H H H H H H H H H
BKW CONSISTENCY M M M M M H H H H H H H
EKN CONSISTENCY M M M M M M M M M M M H
PKB CONSISTENCY H H H H H M M M M M M H
CKB CONSISTENCY H H H M M M M M M M M H
AFTER 12Z WEDNESDAY...
UPPER AIR DISTURBANCE WEDNESDAY/WEDNESDAY NIGHT COULD BRING LIGHT SNOW
WITH IFR.
IFR POSSIBLE WITH A WINTER STORM SYSTEM THURSDAY NIGHT INTO
SATURDAY.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...WIND CHILL ADVISORY UNTIL NOON EST TODAY FOR WVZ038-046-047.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...KTB/30
NEAR TERM...30/26
SHORT TERM...KTB
LONG TERM...TRM
AVIATION...30
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
534 AM EST TUE JAN 19 2016
.SYNOPSIS...
COLD CONTINUES TODAY AND TONIGHT UNDER HIGH PRESSURE AND LIGHTER WINDS.
WEAKENING SYSTEM WEDNESDAY COULD LEAVE MINOR SNOW ACCUMULATIONS. A
MAJOR WINTER STORM DEVELOPS THURSDAY NIGHT AND LINGERS INTO SATURDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
530 AM UPDATE...
STRATOCU REALLY FILLING IN ACROSS THE AREA DURING THESE PREDAWN
HRS. RADAR IS SHOWING VERY LIGHT RETURNS FROM THESE CLOUDS AND
PEAKING OUTSIDE THE OFFICE REVEALS ICE CRYSTALS OR FLURRIES
FALLING. WILL BEEF UP THE SKY COVER THIS MORNING AND ADD SCT
FLURRIES/ICE CRYSTALS FOR A TIME.
PREVIOUS DISCUSSION BELOW...
PESKY STRATOCU HOLDING STRONG IN THE MOUNTAINS WITH SCT FLURRIES
OR ICE CRYSTALS FALLING. OUTSIDE OF THAT...A PASSING S/W TROF
MAY BRING SOME CLOUDS INTO THE AREA THRU MORNING...ESPECIALLY
ACROSS NE KY/S WV/ AND SW VA WHERE A PASSING FLURRY CANNOT BE
RULED OUT.
HIGH PRESSURE BUILDS INTO THE REGION TODAY WHICH WILL FURTHER
DIMINISH THE WIND. STILL COULD SEE SOME GUSTS IN THE N MOUNTAINS
THOUGH. HI RES MODELS TRYING TO SHOW SOME AFTERNOON STREAKY STRATOCU
DEVELOPING OVER SE OH AND N WV AGAIN TODAY. BUMPED SKY COVER UP A
BIT THERE BUT NOT TO THE DEGREE THE HRRR WOULD SUGGEST. TEMPS TODAY
SHOULD RECOVER ABOUT 5 DEGREES FROM YESTERDAY BUT STILL COLD
OVERALL.
WITH HIGH PRESSURE OVERHEAD TONIGHT...EXPECTING A QUICK FALL IN
TEMPS THIS EVENING...ESPECIALLY OVER AREAS THAT HAVE SNOW ON THE
GROUND. HOWEVER...MID AND HI CLOUDS WILL BE ADVANCING TOWARD THE
AREA LATE WHICH WILL CAP THE FREE FALL. WAA ALOFT WILL ALSO COMMENCE
WHICH SHOULD ALLOW THE HIGHER ELEVATIONS TO SEE A SLOW RISE
OVERNIGHT.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
THE WEAKENING SUPPORT/LIFT ON WEDNESDAY WILL WORK HARD TO SATURATE THE COLUMN
IN THE INITIALLY DRY ARCTIC AIR.
FEATURE IS A COMBO OF A 500 MB TROF AND WARM AIR ADVECTION IN THE LOW LEVELS.
FOR EXAMPLE...THE 850 MB FLOW OF 30 TO 40 KNOTS IS PERPENDICULAR TO THE
850 MB ISOTHERMS VCNTY STL TUESDAY EVENING. BY 18Z WEDNESDAY...THE FLOW
IS ALMOST PARALLEL TO THE ISOTHERMS. NOT MUCH CHANGE TO OUR 1 TO 2 INCH
FORECAST...BUT DID TRY TO DAMPEN THE NORTHERN COUNTIES...INCLUDING THE
ROUTE 50 CORRIDOR TO MOSTLY AN INCH OR LESS OF SNOW ACCUMULATION ON
WEDNESDAY.
MEANWHILE...TRIED TO BOOST PORTIONS OF NORTHEAST KENTUCKY...THE SOUTHERN
COAL FIELDS OF WEST VIRGINIA...BUCHANAN AND DICKENSON COUNTIES IN VIRGINIA
MORE TOWARD THE 2 INCH ACCUMULATION. IF SYSTEM DOES NOT DAMPEN QUICKER
THAN EXPECTED...WINTER WX ADVISORIES WILL LIKELY BE POSTED IN SOME COUNTIES
THAT HAVE THE 2 INCH CRITERIA...WHICH IS THE SAME THEME AS YESTERDAY.
WILL CUT BACK ON HIGH TEMPERATURES IN THE SOUTHWEST ON WEDNESDAY...WHERE
THE SNOW WILL LIKELY REACH THE GROUND IN THE MORNING.
WEDNESDAY SYSTEM LEAVES THE LOW ELEVATIONS SATURATED...COULD NOT COMPLETELY
RULE OUT SOME FREEZING DRIZZLE IN THE MOUNTAINS OR SOUTHERN COUNTIES OVERNIGHT
WEDNESDAY NIGHT IN THE WAKE OF THE SYNOPTIC LIGHT SNOW. YET...WILL NOT INSERT
YET INTO THE FORECAST. NORTHERN COUNTIES HAVE A BETTER CHANCE OF THE
LOWER CLOUDS BREAKING UP BEFORE DAWN THURSDAY.
WILL SLOW DOWN THE INCREASING POPS LATE THURSDAY IN THE EXTREME SOUTH A
FEW HOURS.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
ON THE MIDNIGHT SHIFT THIS TUESDAY MORNING...NO REASON TO MAKE MAJOR CHANGES
TO OUR GRIDS FOR THE MAJOR STORM. AS WE KNOW...MAJOR ADJUSTMENTS ARE WISER
AS WE GET CLOSER...INSTEAD OF SEESAWING DAYS AWAY.
WITH THE MID LEVEL AND 850 MB LOW STILL TO OUR WEST ON FRIDAY...AND A STRONG
SOUTHERLY 40 KNOT 850 MB FLOW INTO SOUTHERN WEST VIRGINIA...WE STILL LIKE
THE FORECAST RAIN WORKING NORTH OVERNIGHT THURSDAY NIGHT INTO FRIDAY
FOR SOUTHERN COUNTIES. WILL NOT ADD A WATER HAZARD AS OF YET...BUT
AGAIN...EVEN THAT COULD NOT BE COMPLETELY RULED OUT FOR SOUTHERN
COUNTIES.
HOW FAR AND QUICKLY THAT WINTRY MIX WORKS NORTH...IS THE QUESTION.
WITH SOME SE COMPONENT THOUGH IN POCAHONTAS COUNTY...WE STILL LIKE
KEEPING MOSTLY SNOW IN POCAHONTAS COUNTY.
00Z ECMWF STILL A BIT FURTHER SOUTH WITH THE MID LEVEL AND 850 MB LOW
CIRCULATION...AND THUS A BIT COLDER AT CRITICAL 850 MB LEVEL.
DID INCREASE POPS FRIDAY NIGHT INTO SATURDAY MORNING IN THE STRONG WRAP
AROUND FROM THE DEEPENING STORM TO OUR EAST.
REST OF THIS LONG TERM IS FROM OUR LATE MONDAY PACKAGE...
MODELS AGREE ON THE POTENTIAL FOR A MAJOR WINTER WEATHER SYSTEM
IMPACTING THE AREA EARLY IN THE PERIOD.
A MIDSTREAM UPPER LEVEL S/W TROUGH DIGS SEWD THROUGH THE SRN
PLAINS STATES THU...TOWARD A L/W TROUGH POSITION E OF THE
MISSISSIPPI RIVER...WITH A RIDGE BUILDING TO ITS W. THE S/W
TROUGH CLOSES OFF FRI...TRACKS ACROSS THE SRN APPALACHIANS FRI
NT...AND THEN MEANDERS UP ALONG THE ERN SEABOARD ON SAT.
THE INITIAL SFC LOW CENTER TRACKS NEWD INTO SE KY AND SW VA THU
EVENING...WITH THE INVERTED LOW LEVEL TROUGH EXTENDING NWD UP
ALONG THE OHIO RIVER...PEAKING THE WARM WEDGE EFFECT AT THAT TIME.
THAT CENTER THEN FILLS OVERNIGHT AS THE NEW LOW CENTER GETS GOING
ALONG THE EASTERN SEABOARD. THAT CENTER SLOWLY MEANDERS UP THE
EASTERN SEABOARD SAT AND SAT NT...BEFORE FINALLY PULLING OUT TO
SEA ON SUNDAY.
THIS SCENARIO IS LIKELY TO RESULT IN SNOW OVERSPREADING THE AREA
FROM S TO N THU NT...WITH A TRANSITION TO SLEET AND THEN RAIN
INTO CENTRAL PORTIONS OF THE FCST AREA FROM THE S. FREEZING RAIN
IS ALSO POSSIBLE IN THE TRANSITION. THE HIGHEST LOW LEVEL
TEMPERATURES WILL OCCUR IN THE WARM WEDGE BETWEEN THE OHIO RIVER
AND THE WV MOUNTAINS. SFC TEMPERATURES SHOULD PEAK MID TO LATE
AFTERNOON FRI...BUT THE WARM WEDGE ALOFT STARTS PUSHING EWD LATE
FRI AFTERNOON. THIS COMBINATION KEEPS THE FREEZING RAIN POTENTIAL
IN THE MORNING AND MIDDAY FRI...MAINLY FOR SRN PORTIONS OF THE
AREA AND ALONG THE ERN SLOPES OF THE SRN WV MOUNTAINS.
ACCUMULATIONS THU NT AS LIKELY TO BE LIMITED OVER THE SRN COAL
FIELDS OF WV ON ACCOUNT OF SFC TEMPERATURES THERE GETTING ABOVE
FREEZING SOON AFTER THE ONSET OF THE PRECIPITATION. AN INCH OR
TWO ARE POSSIBLE ELSEWHERE BY DAWN FRI...DEPENDING UPON HOW
QUICKLY SLEET MIXES IN RELATIVE TO THE ONSET TIME OF THE
PRECIPITATION. THE CENTRAL MOUNTAINS APPEAR MOST LIKELY TO GET
SEVERAL INCHES BY DAWN FRI AS THAT IS WHERE THERE IS LIKELY TO BE
THE MOST TIME BETWEEN THE ONSET OF THE PRECIPITATION AND THE
ARRIVAL OF ABOVE FREEZING TEMPERATURES ALOFT.
AS THE UPPER LEVEL LOW ROLLS S OF THE AREA FRI NT...THE LOW LEVEL
INVERTED TROUGH AND WARM WEDGE COLLAPSE...AND TEMPERATURES FALL
BELOW FREEZING THROUGHOUT THE COLUMN THROUGHOUT THE FCST AREA.
SNOW ACCUMULATIONS WILL DEPEND UPON THE PROGRESS OF THE WARM
WEDGE ON FRI...AND THEN HOW MUCH FORCING / DEFORMATION EXISTS OVER
THE AREA FRI NT AS THE COLD AIR SETTLES IN.
THE AIR MASS BEHIND THIS SYSTEM WILL ACTUALLY BE OF PACIFIC ORIGIN
AND THUS BE ONLY SEASONABLY CHILLY...AND THE NEXT WARM ADVECTION
SYSTEM NEXT MON BRINGS THE CHANCE FOR A LIGHT SNOW TO RAIN
TRANSITION.
WPC TEMPERATURES LOOKED REASONABLE AND WERE GENERALLY BLENDED IN.
HAVE TEMPERATURES RISING TOWARD DAWN FRI WITH THE WARM WEDGE
EFFECT BEGINNING TO TAKE HOLD...USED GFS BASED TEMPERATURES IN
ADDITION TO WPC DURING THE STORM...THU NT INTO SAT.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
AREAS OF MVFR STRATOCU THIS MORNING ALONG WITH SOME FLURRIES AND
ICE CRYSTALS EXPECTED THROUGH AROUND 15Z ACROSS S TERMINALS AND
MOUNTAIN TERMINALS.
AFTERNOON MVFR STRATOCU MAY REDEVELOP AGAIN ACROSS SE OH AND N
WV...AFFECTING KPKB/KCKB/KEKN WITH A PERIOD OF BKN MVFR CIGS.
MID AND HI CLOUDS ADVANCE INTO THE AREA FROM THE W TONIGHT AS ANY
REMAINING STRATOCU DISSIPATES.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z WEDNESDAY...
FORECAST CONFIDENCE...HIGH
ALTERNATE SCENARIOS: NONE
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
DATE TUE 01/19/16
UTC 1HRLY 10 11 12 13 14 15 16 17 18 19 20 21
EST 1HRLY 05 06 07 08 09 10 11 12 13 14 15 16
CRW CONSISTENCY H H H H H H H H H H H H
HTS CONSISTENCY H H H H H H H H H H H H
BKW CONSISTENCY H H H H H H H H H H H H
EKN CONSISTENCY M M M M M M M M M M M M
PKB CONSISTENCY H H H H H M M M M M M M
CKB CONSISTENCY H H H H H H M M M M M M
AFTER 12Z WEDNESDAY...
UPPER AIR DISTURBANCE WEDNESDAY/WEDNESDAY NIGHT COULD BRING LIGHT SNOW
WITH IFR.
IFR POSSIBLE WITH A WINTER STORM SYSTEM THURSDAY NIGHT INTO
SATURDAY.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...WIND CHILL ADVISORY UNTIL NOON EST TODAY FOR WVZ038-046-047.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...KTB/30
NEAR TERM...30
SHORT TERM...KTB
LONG TERM...TRM
AVIATION...30
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
415 AM EST TUE JAN 19 2016
.SYNOPSIS... COLD CONTINUES INTO TODAY UNDER HIGH PRESSURE.
WEAKENING SYSTEM WEDNESDAY COULD LEAVE MINOR SNOW ACCUMULATIONS.
POTENTIAL FOR A SIGNIFICANT WINTER STORM THURSDAY NIGHT INTO
SATURDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
PESKY STRATOCU HOLDING STRONG IN THE MOUNTAINS WITH SCT FLURRIES
OR ICE CRYSTALS FALLING. OUTSIDE OF THAT...A PASSING S/W TROF
MAY BRING SOME CLOUDS INTO THE AREA THRU MORNING...ESPECIALLY
ACROSS NE KY/S WV/ AND SW VA WHERE A PASSING FLURRY CANNOT BE
RULED OUT.
HIGH PRESSURE BUILDS INTO THE REGION TODAY WHICH WILL FURTHER
DIMINISH THE WIND. STILL COULD SEE SOME GUSTS IN THE N MOUNTAINS
THOUGH. HI RES MODELS TRYING TO SHOW SOME AFTERNOON STREAKY STRATOCU
DEVELOPING OVER SE OH AND N WV AGAIN TODAY. BUMPED SKY COVER UP A
BIT THERE BUT NOT TO THE DEGREE THE HRRR WOULD SUGGEST. TEMPS TODAY
SHOULD RECOVER ABOUT 5 DEGREES FROM YESTERDAY BUT STILL COLD
OVERALL.
WITH HIGH PRESSURE OVERHEAD TONIGHT...EXPECTING A QUICK FALL IN
TEMPS THIS EVENING...ESPECIALLY OVER AREAS THAT HAVE SNOW ON THE
GROUND. HOWEVER...MID AND HI CLOUDS WILL BE ADVANCING TOWARD THE
AREA LATE WHICH WILL CAP THE FREE FALL. WAA ALOFT WILL ALSO COMMENCE
WHICH SHOULD ALLOW THE HIGHER ELEVATIONS TO SEE A SLOW RISE
OVERNIGHT.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
THE WEAKENING SUPPORT/LIFT ON WEDNESDAY WILL WORK HARD TO SATURATE THE COLUMN
IN THE INITIALLY DRY ARCTIC AIR.
FEATURE IS A COMBO OF A 500 MB TROF AND WARM AIR ADVECTION IN THE LOW LEVELS.
FOR EXAMPLE...THE 850 MB FLOW OF 30 TO 40 KNOTS IS PERPENDICULAR TO THE
850 MB ISOTHERMS VCNTY STL TUESDAY EVENING. BY 18Z WEDNESDAY...THE FLOW
IS ALMOST PARALLEL TO THE ISOTHERMS. NOT MUCH CHANGE TO OUR 1 TO 2 INCH
FORECAST...BUT DID TRY TO DAMPEN THE NORTHERN COUNTIES...INCLUDING THE
ROUTE 50 CORRIDOR TO MOSTLY AN INCH OR LESS OF SNOW ACCUMULATION ON
WEDNESDAY.
MEANWHILE...TRIED TO BOOST PORTIONS OF NORTHEAST KENTUCKY...THE SOUTHERN
COAL FIELDS OF WEST VIRGINIA...BUCHANAN AND DICKENSON COUNTIES IN VIRGINIA
MORE TOWARD THE 2 INCH ACCUMULATION. IF SYSTEM DOES NOT DAMPEN QUICKER
THAN EXPECTED...WINTER WX ADVISORIES WILL LIKELY BE POSTED IN SOME COUNTIES
THAT HAVE THE 2 INCH CRITERIA...WHICH IS THE SAME THEME AS YESTERDAY.
WILL CUT BACK ON HIGH TEMPERATURES IN THE SOUTHWEST ON WEDNESDAY...WHERE
THE SNOW WILL LIKELY REACH THE GROUND IN THE MORNING.
WEDNESDAY SYSTEM LEAVES THE LOW ELEVATIONS SATURATED...COULD NOT COMPLETELY
RULE OUT SOME FREEZING DRIZZLE IN THE MOUNTAINS OR SOUTHERN COUNTIES OVERNIGHT
WEDNESDAY NIGHT IN THE WAKE OF THE SYNOPTIC LIGHT SNOW. YET...WILL NOT INSERT
YET INTO THE FORECAST. NORTHERN COUNTIES HAVE A BETTER CHANCE OF THE
LOWER CLOUDS BREAKING UP BEFORE DAWN THURSDAY.
WILL SLOW DOWN THE INCREASING POPS LATE THURSDAY IN THE EXTREME SOUTH A
FEW HOURS.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
ON THE MIDNIGHT SHIFT THIS TUESDAY MORNING...NO REASON TO MAKE MAJOR CHANGES
TO OUR GRIDS FOR THE MAJOR STORM. AS WE KNOW...MAJOR ADJUSTMENTS ARE WISER
AS WE GET CLOSER...INSTEAD OF SEESAWING DAYS AWAY.
WITH THE MID LEVEL AND 850 MB LOW STILL TO OUR WEST ON FRIDAY...AND A STRONG
SOUTHERLY 40 KNOT 850 MB FLOW INTO SOUTHERN WEST VIRGINIA...WE STILL LIKE
THE FORECAST RAIN WORKING NORTH OVERNIGHT THURSDAY NIGHT INTO FRIDAY
FOR SOUTHERN COUNTIES. WILL NOT ADD A WATER
HAZARD AS OF YET...BUT AGAIN...EVEN THAT COULD NOT BE COMPLETELY RULED
OUT FOR SOUTHERN COUNTIES.
HOW FAR AND QUICKLY THAT WORKS...IS THE QUESTION. WITH SOME SE COMPONENT
THOUGH IN POCAHONTAS COUNTY...WE STILL LIKE KEEPING MOSTLY SNOW IN
POCAHONTAS COUNTY.
00Z ECMWF STILL A BIT FURTHER SOUTH WITH THE MID LEVEL AND 850 MB LOW
CIRCULATION...AND THUS A BIT COLDER AT CRITICAL 850 MB LEVEL.
DID INCREASE POPS FRIDAY NIGHT INTO SATURDAY MORNING IN THE STRONG WRAP
AROUND FROM THE DEEPENING STORM.
REST OF THIS LONG TERM IS FROM OUR LATE MONDAY PACKAGE...
MODELS AGREE ON THE POTENTIAL FOR A MAJOR WINTER WEATHER SYSTEM
IMPACTING THE AREA EARLY IN THE PERIOD.
A MIDSTREAM UPPER LEVEL S/W TROUGH DIGS SEWD THROUGH THE SRN
PLAINS STATES THU...TOWARD A L/W TROUGH POSITION E OF THE
MISSISSIPPI RIVER...WITH A RIDGE BUILDING TO ITS W. THE S/W
TROUGH CLOSES OFF FRI...TRACKS ACROSS THE SRN APPALACHIANS FRI
NT...AND THEN MEANDERS UP ALONG THE ERN SEABOARD ON SAT.
THE INITIAL SFC LOW CENTER TRACKS NEWD INTO SE KY AND SW VA THU
EVENING...WITH THE INVERTED LOW LEVEL TROUGH EXTENDING NWD UP
ALONG THE OHIO RIVER...PEAKING THE WARM WEDGE EFFECT AT THAT TIME.
THAT CENTER THEN FILLS OVERNIGHT AS THE NEW LOW CENTER GETS GOING
ALONG THE EASTERN SEABOARD. THAT CENTER SLOWLY MEANDERS UP THE
EASTERN SEABOARD SAT AND SAT NT...BEFORE FINALLY PULLING OUT TO
SEA ON SUNDAY.
THIS SCENARIO IS LIKELY TO RESULT IN SNOW OVERSPREADING THE AREA
FROM S TO N THU NT...WITH A TRANSITION TO SLEET AND THEN RAIN
INTO CENTRAL PORTIONS OF THE FCST AREA FROM THE S. FREEZING RAIN
IS ALSO POSSIBLE IN THE TRANSITION. THE HIGHEST LOW LEVEL
TEMPERATURES WILL OCCUR IN THE WARM WEDGE BETWEEN THE OHIO RIVER
AND THE WV MOUNTAINS. SFC TEMPERATURES SHOULD PEAK MID TO LATE
AFTERNOON FRI...BUT THE WARM WEDGE ALOFT STARTS PUSHING EWD LATE
FRI AFTERNOON. THIS COMBINATION KEEPS THE FREEZING RAIN POTENTIAL
IN THE MORNING AND MIDDAY FRI...MAINLY FOR SRN PORTIONS OF THE
AREA AND ALONG THE ERN SLOPES OF THE SRN WV MOUNTAINS.
ACCUMULATIONS THU NT AS LIKELY TO BE LIMITED OVER THE SRN COAL
FIELDS OF WV ON ACCOUNT OF SFC TEMPERATURES THERE GETTING ABOVE
FREEZING SOON AFTER THE ONSET OF THE PRECIPITATION. AN INCH OR
TWO ARE POSSIBLE ELSEWHERE BY DAWN FRI...DEPENDING UPON HOW
QUICKLY SLEET MIXES IN RELATIVE TO THE ONSET TIME OF THE
PRECIPITATION. THE CENTRAL MOUNTAINS APPEAR MOST LIKELY TO GET
SEVERAL INCHES BY DAWN FRI AS THAT IS WHERE THERE IS LIKELY TO BE
THE MOST TIME BETWEEN THE ONSET OF THE PRECIPITATION AND THE
ARRIVAL OF ABOVE FREEZING TEMPERATURES ALOFT.
AS THE UPPER LEVEL LOW ROLLS S OF THE AREA FRI NT...THE LOW LEVEL
INVERTED TROUGH AND WARM WEDGE COLLAPSE...AND TEMPERATURES FALL
BELOW FREEZING THROUGHOUT THE COLUMN THROUGHOUT THE FCST AREA.
SNOW ACCUMULATIONS WILL DEPEND UPON THE PROGRESS OF THE WARM
WEDGE ON FRI...AND THEN HOW MUCH FORCING / DEFORMATION EXISTS OVER
THE AREA FRI NT AS THE COLD AIR SETTLES IN.
THE AIR MASS BEHIND THIS SYSTEM WILL ACTUALLY BE OF PACIFIC ORIGIN
AND THUS BE ONLY SEASONABLY CHILLY...AND THE NEXT WARM ADVECTION
SYSTEM NEXT MON BRINGS THE CHANCE FOR A LIGHT SNOW TO RAIN
TRANSITION.
WPC TEMPERATURES LOOKED REASONABLE AND WERE GENERALLY BLENDED IN.
HAVE TEMPERATURES RISING TOWARD DAWN FRI WITH THE WARM WEDGE
EFFECT BEGINNING TO TAKE HOLD...USED GFS BASED TEMPERATURES IN
ADDITION TO WPC DURING THE STORM...THU NT INTO SAT.
&&
.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
MAINLY VFR CONDITIONS EXCEPT MVFR CIGS IN THE MOUNTAINS THRU THIS
MORNING. SOME -SHSN AND FLURRIES EXPECTED THROUGH AROUND 12Z
TUESDAY ACROSS THE NORTHERN MOUNTAIN ZONES AS WELL AS SE
OH...CREATING BRIEF LOW VFR OR EVEN BRIEF MVFR VSBYS.
OTHERWISE...VFR WITH LIGHT WEST TO WEST- NORTHWESTERLY WINDS.
AFTERNOON MVFR STRATOCU MAY DEVELOP AGAIN ACROSS SE OH AND N
WV...AFFECTING KPKB/KCKB/KEKN WITH A PERIOD OF BKN MVFR CIGS.
MID AND HI CLOUDS ADVANCE INTO THE AREA FROM THE W TONIGHT AS ANY
REMAINING STRATOCU DISSIPATES.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z WEDNESDAY...
FORECAST CONFIDENCE...HIGH
ALTERNATE SCENARIOS: NONE
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
DATE TUE 01/19/16
UTC 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17
EST 1HRLY 01 02 03 04 05 06 07 08 09 10 11 12
CRW CONSISTENCY H H H H H H H H H H H H
HTS CONSISTENCY H H H H H H H H H H H H
BKW CONSISTENCY H H H H H H H H H H H H
EKN CONSISTENCY M M M M M M M M M M M M
PKB CONSISTENCY H H H H H H H H H M M M
CKB CONSISTENCY H H H H H H H H H H M M
AFTER 06Z WEDNESDAY...
UPPER AIR DISTURBANCE WEDNESDAY/WEDNESDAY NIGHT COULD BRING LIGHT SNOW
WITH IFR.
IFR POSSIBLE WITH A WINTER STORM SYSTEM THURSDAY NIGHT INTO
SATURDAY.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...WIND CHILL ADVISORY UNTIL NOON EST TODAY FOR WVZ038-046-047.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...KTB/30
NEAR TERM...30
SHORT TERM...KTB
LONG TERM...TRM
AVIATION...30
AREA FORECAST DISCUSSION
NWS Tulsa OK
909 PM CST WED JAN 20 2016
.DISCUSSION...
Precipitation is starting to develop to the west of the Tulsa
CWA this evening as a mid-level shortwave works across Oklahoma.
With temperatures slowly creeping upwards across northern portions
of the forecast area through the evening...the forecast has become
somewhat trickier. The HRRR is doing a good job of developing precipitation
across the area and expect the precip shield to continue to blossom through
the night. Precip type is the tricky part. After looking at the latest
NAM forecast soundings, light snow and freezing drizzle seem like the best
bet across far north Oklahoma and into northwest Arkansas tonight. However,
some heavier freezing rain/rain may also develop across these areas. With
temperatures so close to freezing and still some uncertainty in the forecast
will not issue and advisory at this time. However, we will continue to closely
monitor and refine the forecast. Further to the south, mainly rain is expected.
however, a few pockets below the freezing mark will see freezing rain and possibly
sleet. There is also enough elevated instability for a few thunderstorms across
southeast Oklahoma tonight.
&&
.TSA Watches/Warnings/Advisories...
OK...NONE.
AR...NONE.
&&
$$
SHORT TERM...10
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1034 AM EST TUE JAN 19 2016
.SYNOPSIS...
ACCUMULATING LAKE EFFECT SNOW WILL TAPER OFF THROUGH THE
AFTERNOON. LIGHT SNOW IS POSSIBLE LATER WEDNESDAY OVER THE
WESTERN MOUNTAINS. A MAJOR WINTER STORM COULD BRING SIGNIFICANT
SNOWFALL TO MUCH OF CENTRAL PA FRIDAY INTO SATURDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
1030 AM UPDATE...
LES HANGING ON ACROSS THE FAR NW AND FLURRIES OVER THE LAURELS.
WILL LINGER MORE OF THE SAME IN THE FORECAST THROUGH THE REST OF
THE DAY. SUBSIDENCE IS TRYING TO KILL THE CLOUDS...BUT THEY SEEM
TO BE EXPANDING GRADUALLY TO THE SOUTH. BUT ANYWHERE THERE IS
DOWNSLOPE THE CLOUDS DISAPPEAR. TEMPS/WIND CHILLS LOOK ON TRACK.
HAVE ALLOWED THE WC ADVY TO DIE AS ONLY A FEW SUB-15-BELOW NUMBERS
WILL BE HAD FOR A FEW MORE HOURS AS TEMPS RISE. WIND DOES NOT
SLACKEN MUCH...THOUGH.
635 AM UPDATE...CANCELLED THE LES WARNINGS FOR WARREN AND MCKEAN.
THE HEAVIEST LAKE EFFECT IS OVER WITH DIMINISHING COVERAGE TREND
EXPECTED BY AFTERNOON. AN ADDITIONAL 1-2 INCHES IS POSSIBLE IN
THE MOST PERSISTENT BANDS THIS MORNING.
PREVIOUS...MODELS DEPICT A STRONG LOBE OF VORTICITY SWINGING
THROUGH PA BY 18Z. HRRR SHOWS LES BANDS WEAKENING THROUGH THE
MORNING BEFORE TAPERING OFF BY TONIGHT...AS INCREASINGLY
ANTICYCLONIC LOW TO MID LEVEL FLOW PUSHES ACROSS THE LAKES. WITH
ONLY MINOR ADDITIONAL LES ACCUMULATIONS EXPECTED...WILL ALLOW THE
LES HEADLINES EXPIRE AS SCHEDULED AT 12Z/7AM. WIND CHILL HAZARD
ALSO ON TRACK TO EXPIRE AT 10AM AS MINIMUM WIND CHILLS TREND INTO
THE NEGATIVE SINGLE DIGITS. OVERALL IT WILL BE ANOTHER BRISK AND
VERY COLD DAY WITH WIND CHILLS IN THE SINGLE DIGITS +/- ZERO. WEAK
RIDGING SURFACE AND ALOFT SLIDES INTO THE AREA FROM THE OH VALLEY
TONIGHT WITH NO SIGNIFICANT WEATHER EXPECTED. LOWS WILL RANGE FROM
THE POSITIVE SINGLE DIGITS IN THE LAURELS TO THE MID TEENS ACROSS
THE MID TO LOWER SUSQUEHANNA VALLEY.
&&
.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/...
SPLIT FLOW TROUGH WILL MIGRATE QUICKLY EASTWARD FROM THE PLAINS TO
THE EAST COAST BY 21/1200Z. MODELS SHOW THE NORTHERN STREAM SYSTEM
BEING MORE AMPLIFIED AS IT TRACKS FROM THE MIDWEST THROUGH THE NRN
MID-ATLANTIC STATES. WITH MOISTURE LACKING...MODEST HEIGHT FALLS
COULD COMBINE WITH WEAK WAA TO BRING A PERIOD OF LIGHT SNOW OVER
THE ALLEGHENY RIDGES LATER WEDNESDAY INTO WEDNESDAY NIGHT. ANY
SNOW ACCUMS WOULD BE AN INCH OR LESS BASED ON BLENDED MEAN QPF.
FOLLOWING THE PASSAGE OF THE AFOREMENTIONED NORTHERN STREAM
SYSTEM...LAKE EFFECT TRAJECTORIES BECOME REESTABLISHED WITH MINOR
ACCUMS POSSIBLE IN THE NORTHWEST SNOWBELT. THE LES CONNECTION
APPEARS TO BE RATHER SHORT-LIVED ESPECIALLY FROM ERIE.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
THURSDAY FCST/DAY 3 WX LOOKS QUIET UNDER HIGH PRESSURE. ALL EYES
WILL TURN TO LOW PRESSURE SYSTEM DEVELOPING INTO THE TN VALLEY
AND SOUTHERN APPALACHIANS BY THURSDAY NIGHT.
THE PRIMARY IMPACTS THIS PERIOD WILL BE FOR GROWING CONFIDENCE IN
A MAJOR EAST COAST WINTER STORM INCLUDING HEAVY SNOW POTENTIAL IN
CENTRAL PENNSYLVANIA. EXPECT THE MODEL SPREAD WITH THIS SYSTEM TO
CONTINUE TO NARROW AS THE UPPER LEVEL FEATURE COMES ONSHORE OVER
THE PACIFIC NW TONIGHT. WHILE IT IS STILL TO EARLY TO GET INTO THE
SPECIFIC DETAILS...HERE ARE SOME EARLY GOAL POSTS:
PTYPE: MODEL CONSENSUS AT THIS TIME FAVORS SNOW AS THE PRIMARY
WINTER PTYPE NEAR AND NORTHWEST OF THE I-95 URBAN CORRIDOR
TIMING: GFS/CMC/WPC QPF WOULD SUGGEST A FRIDAY MORNING ONSET
SPREADING FROM SOUTH TO NORTH BY THE AFTERNOON. THE ECMWF IS
SLOWER.
DURATION: SNOW COULD LAST THROUGH SATURDAY BEFORE ENDING SATURDAY
NIGHT/EARLY SUNDAY MORNING.
GREATEST RISK FOR HEAVY SNOW: SOUTH-CENTRAL AND SOUTHEASTERN
ZONES OR ROUGHLY THE SOUTHEAST 1/2 TO 1/3 OF THE CWA. BLOWING AND
DRIFTING POSSIBLE.
IMPROVING CONDITIONS LIKELY ARE ON SUNDAY WITH HIGH PRESSURE
RETURNING TO THE AREA. TEMPERATURES ARE FCST TO TREND WARMER TO
NEAR NORMAL LEVELS BY MONDAY.
&&
.AVIATION /16Z TUESDAY THROUGH SATURDAY/...
WILL LINGER LOWERED VIS/CIGS OVER THE NW FOR A FEW MORE HOURS AT
EACH SITE. KBFD MAY CONTINUE TO HAVE IFR VIS FOR MUCH OF THE AFTN
AS CROSS LAKE FLOW STILL MAKES IT FAVORABLE. KJST ALSO NOT
IMPROVING MUCH AND WILL CONTINUE ON WITH THOSE FOR ANOTHER FEW
HRS.
PREV...
PERSISTENT SNOW BAND REMAINS ACROSS THE NW MTNS. THIS CONTINUES TO
BRING IFR AND LOWER VSBYS TO BFD. THE GUSTY FLOW SHOULD CONTINUE
THE LAKE EFFECT THROUGH THE MORNING. THE WINDS SHOULD SHIFT TO THE
NORTH...THOUGH THIS ALONE WILL NOT CEASE ANY SHOWERS. HOWEVER...A
BUILDING RIDGE WILL REDUCE INSTABILITY ENOUGH TUESDAY AFTERNOON TO
END SHOWER ACTIVITY AND ALLOW FOR IMPROVING CONDITIONS.
IMPROVING CONDS AT KJST...THOUGH UPSLOPE FLOW HAS BROUGHT MVFR
CIGS TO AOO...UNV AND JST. FOR THE REST OF CENTRAL PA...THE
DRYING EFFECT OF DOWNSLOPING WESTERLY FLOW SHOULD YIELD VFR FLYING
OVERNIGHT.
HIGH PRESSURE BUILDING IN FROM THE MIDWEST WILL CAUSE LAKE EFFECT
SNOW TO TAPER OFF ACROSS THE NW MTNS TUESDAY. HOWEVER...RESIDUAL
LOW LVL MOISTURE ASCENDING THE ALLEGHENIES SHOULD CAUSE MVFR
STRATOCU TO PERSIST INTO TUE EVENING AT KBFD AND KJST. AFTER A BIT
OF A LULL IN THE WINDS OVERNIGHT...EXPECT GUSTY WINDS TO REDEVELOP ACROSS
THE ENTIRE AREA FROM LATE AM THRU EARLY EVENING TUES...AS DIURNAL
HEATING/DEEPENING BLYR DEPTH ALLOW STRONGER WINDS TO MIX TO THE
SFC. BUFKIT SOUNDINGS SUPPORT GUSTS BTWN 25-30KTS TUE AFTN.
OUTLOOK...
WED...A BRIEF EVENING -SHSN/VIS REDUCTION POSSIBLE KJST/KBFD.
THU...NO SIG WX EXPECTED.
FRI...SNOW POSSIBLE...ESP SOUTH.
SAT...SNOW/WIND POSSIBLE...ESP SOUTH/EAST.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...STEINBUGL
NEAR TERM...DANGELO/STEINBUGL
SHORT TERM...STEINBUGL
LONG TERM...STEINBUGL
AVIATION...DANGELO/CERU
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
759 AM EST TUE JAN 19 2016
.SYNOPSIS...
ACCUMULATING LAKE EFFECT SNOW WILL END THIS MORNING. LIGHT SNOW
IS POSSIBLE LATER WEDNESDAY. A MAJOR WINTER STORM COULD BRING
SIGNIFICANT SNOWFALL TO MUCH OF CENTRAL PA FRIDAY INTO SATURDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
635 AM UPDATE...CANCELLED THE LES WARNINGS FOR WARREN AND MCKEAN.
THE HEAVIEST LAKE EFFECT IS OVER WITH DIMINISHING COVERAGE TREND
EXPECTED BY AFTERNOON. AN ADDITIONAL 1-2 INCHES IS POSSIBLE IN
THE MOST PERSISTENT BANDS THIS MORNING.
PREVIOUS...MODELS DEPICT A STRONG LOBE OF VORTICITY SWINGING
THROUGH PA BY 18Z. HRRR SHOWS LES BANDS WEAKENING THROUGH THE
MORNING BEFORE TAPERING OFF BY TONIGHT...AS INCREASINGLY
ANTICYCLONIC LOW TO MID LEVEL FLOW PUSHES ACROSS THE LAKES. WITH
ONLY MINOR ADDITIONAL LES ACCUMULATIONS EXPECTED...WILL ALLOW THE
LES HEADLINES EXPIRE AS SCHEDULED AT 12Z/7AM. WIND CHILL HAZARD
ALSO ON TRACK TO EXPIRE AT 10AM AS MINIMUM WIND CHILLS TREND INTO
THE NEGATIVE SINGLE DIGITS. OVERALL IT WILL BE ANOTHER BRISK AND
VERY COLD DAY WITH WIND CHILLS IN THE SINGLE DIGITS +/- ZERO. WEAK
RIDGING SURFACE AND ALOFT SLIDES INTO THE AREA FROM THE OH VALLEY
TONIGHT WITH NO SIGNIFICANT WEATHER EXPECTED. LOWS WILL RANGE FROM
THE POSITIVE SINGLE DIGITS IN THE LAURELS TO THE MID TEENS ACROSS
THE MID TO LOWER SUSQUEHANNA VALLEY.
&&
.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/...
SPLIT FLOW TROUGH WILL MIGRATE QUICKLY EASTWARD FROM THE PLAINS TO
THE EAST COAST BY 21/1200Z. MODELS SHOW THE NORTHERN STREAM SYSTEM
BEING MORE AMPLIFIED AS IT TRACKS FROM THE MIDWEST THROUGH THE NRN
MID-ATLANTIC STATES. WITH MOISTURE LACKING...MODEST HEIGHT FALLS
COULD COMBINE WITH WEAK WAA TO BRING A PERIOD OF LIGHT SNOW OVER
THE ALLEGHENY RIDGES LATER WEDNESDAY INTO WEDNESDAY NIGHT. ANY
SNOW ACCUMS WOULD BE AN INCH OR LESS BASED ON BLENDED MEAN QPF.
FOLLOWING THE PASSAGE OF THE AFOREMENTIONED NORTHERN STREAM
SYSTEM...LAKE EFFECT TRAJECTORIES BECOME REESTABLISHED WITH MINOR
ACCUMS POSSIBLE IN THE NORTHWEST SNOWBELT. THE LES CONNECTION
APPEARS TO BE RATHER SHORT-LIVED ESPECIALLY FROM ERIE.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
THURSDAY FCST/DAY 3 WX LOOKS QUIET UNDER HIGH PRESSURE. ALL EYES
WILL TURN TO LOW PRESSURE SYSTEM DEVELOPING INTO THE TN VALLEY
AND SOUTHERN APPALACHIANS BY THURSDAY NIGHT.
THE PRIMARY IMPACTS THIS PERIOD WILL BE FOR GROWING CONFIDENCE IN
A MAJOR EAST COAST WINTER STORM INCLUDING HEAVY SNOW POTENTIAL IN
CENTRAL PENNSYLVANIA. EXPECT THE MODEL SPREAD WITH THIS SYSTEM TO
CONTINUE TO NARROW AS THE UPPER LEVEL FEATURE COMES ONSHORE OVER
THE PACIFIC NW TONIGHT. WHILE IT IS STILL TO EARLY TO GET INTO THE
SPECIFIC DETAILS...HERE ARE SOME EARLY GOAL POSTS:
PTYPE: MODEL CONSENSUS AT THIS TIME FAVORS SNOW AS THE PRIMARY
WINTER PTYPE NEAR AND NORTHWEST OF THE I-95 URBAN CORRIDOR
TIMING: GFS/CMC/WPC QPF WOULD SUGGEST A FRIDAY MORNING ONSET
SPREADING FROM SOUTH TO NORTH BY THE AFTERNOON. THE ECMWF IS
SLOWER.
DURATION: SNOW COULD LAST THROUGH SATURDAY BEFORE ENDING SATURDAY
NIGHT/EARLY SUNDAY MORNING.
GREATEST RISK FOR HEAVY SNOW: SOUTH-CENTRAL AND SOUTHEASTERN
ZONES OR ROUGHLY THE SOUTHEAST 1/2 TO 1/3 OF THE CWA. BLOWING AND
DRIFTING POSSIBLE.
IMPROVING CONDITIONS LIKELY ARE ON SUNDAY WITH HIGH PRESSURE
RETURNING TO THE AREA. TEMPERATURES ARE FCST TO TREND WARMER TO
NEAR NORMAL LEVELS BY MONDAY.
&&
.AVIATION /13Z TUESDAY THROUGH SATURDAY/...
PERSISTENT SNOW BAND REMAINS ACROSS THE NW MTNS. THIS CONTINUES TO
BRING IFR AND LOWER VSBYS TO BFD. THE GUSTY FLOW SHOULD CONTINUE
THE LAKE EFFECT THROUGH THE MORNING. THE WINDS SHOULD SHIFT TO THE
NORTH...THOUGH THIS ALONE WILL NOT CEASE ANY SHOWERS. HOWEVER...A
BUILDING RIDGE WILL REDUCE INSTABILITY ENOUGH TUESDAY AFTERNOON TO
END SHOWER ACTIVITY AND ALLOW FOR IMPROVING CONDITIONS.
IMPROVING CONDS AT KJST...THOUGH UPSLOPE FLOW HAS BROUGHT MVFR
CIGS TO AOO...UNV AND JST. FOR THE REST OF CENTRAL PA...THE
DRYING EFFECT OF DOWNSLOPING WESTERLY FLOW SHOULD YIELD VFR FLYING
OVERNIGHT.
HIGH PRESSURE BUILDING IN FROM THE MIDWEST WILL CAUSE LAKE EFFECT
SNOW TO TAPER OFF ACROSS THE NW MTNS TUESDAY. HOWEVER...RESIDUAL
LOW LVL MOISTURE ASCENDING THE ALLEGHENIES SHOULD CAUSE MVFR
STRATOCU TO PERSIST INTO TUE EVENING AT KBFD AND KJST. AFTER A BIT
OF A LULL IN THE WINDS OVERNIGHT...EXPECT GUSTY WINDS TO REDEVELOP ACROSS
THE ENTIRE AREA FROM LATE AM THRU EARLY EVENING TUES...AS DIURNAL
HEATING/DEEPENING BLYR DEPTH ALLOW STRONGER WINDS TO MIX TO THE
SFC. BUFKIT SOUNDINGS SUPPORT GUSTS BTWN 25-30KTS TUE AFTN.
OUTLOOK...
WED...A BRIEF EVENING -SHSN/VIS REDUCTION POSSIBLE KJST/KBFD.
THU...NO SIG WX EXPECTED.
FRI...SNOW POSSIBLE...ESP SOUTH.
SAT...SNOW/WIND POSSIBLE...ESP SOUTH/EAST.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY UNTIL 10 AM EST THIS MORNING FOR PAZ024-
033.
&&
$$
SYNOPSIS...STEINBUGL
NEAR TERM...STEINBUGL
SHORT TERM...STEINBUGL
LONG TERM...STEINBUGL
AVIATION...FITZGERALD/CERU
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
637 AM EST TUE JAN 19 2016
.SYNOPSIS...
ACCUMULATING LAKE EFFECT SNOW WILL END THIS MORNING. LIGHT SNOW
IS POSSIBLE LATER WEDNESDAY. A MAJOR WINTER STORM COULD BRING
SIGNIFICANT SNOWFALL TO MUCH OF CENTRAL PA FRIDAY INTO SATURDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
635 AM UPDATE...CANCELLED THE LES WARNINGS FOR WARREN AND MCKEAN.
THE HEAVIEST LAKE EFFECT IS OVER WITH DIMINISHING COVERAGE TREND
EXPECTED BY AFTERNOON. AN ADDITIONAL 1-2 INCHES IS POSSIBLE IN
THE MOST PERSISTENT BANDS THIS MORNING.
PREVIOUS...MODELS DEPICT A STRONG LOBE OF VORTICITY SWINGING
THROUGH PA BY 18Z. HRRR SHOWS LES BANDS WEAKENING THROUGH THE
MORNING BEFORE TAPERING OFF BY TONIGHT...AS INCREASINGLY
ANTICYCLONIC LOW TO MID LEVEL FLOW PUSHES ACROSS THE LAKES. WITH
ONLY MINOR ADDITIONAL LES ACCUMULATIONS EXPECTED...WILL ALLOW THE
LES HEADLINES EXPIRE AS SCHEDULED AT 12Z/7AM. WIND CHILL HAZARD
ALSO ON TRACK TO EXPIRE AT 10AM AS MINIMUM WIND CHILLS TREND INTO
THE NEGATIVE SINGLE DIGITS. OVERALL IT WILL BE ANOTHER BRISK AND
VERY COLD DAY WITH WIND CHILLS IN THE SINGLE DIGITS +/- ZERO. WEAK
RIDGING SURFACE AND ALOFT SLIDES INTO THE AREA FROM THE OH VALLEY
TONIGHT WITH NO SIGNIFICANT WEATHER EXPECTED. LOWS WILL RANGE FROM
THE POSITIVE SINGLE DIGITS IN THE LAURELS TO THE MID TEENS ACROSS
THE MID TO LOWER SUSQUEHANNA VALLEY.
&&
.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/...
SPLIT FLOW TROUGH WILL MIGRATE QUICKLY EASTWARD FROM THE PLAINS TO
THE EAST COAST BY 21/1200Z. MODELS SHOW THE NORTHERN STREAM SYSTEM
BEING MORE AMPLIFIED AS IT TRACKS FROM THE MIDWEST THROUGH THE NRN
MID-ATLANTIC STATES. WITH MOISTURE LACKING...MODEST HEIGHT FALLS
COULD COMBINE WITH WEAK WAA TO BRING A PERIOD OF LIGHT SNOW OVER
THE ALLEGHENY RIDGES LATER WEDNESDAY INTO WEDNESDAY NIGHT. ANY
SNOW ACCUMS WOULD BE AN INCH OR LESS BASED ON BLENDED MEAN QPF.
FOLLOWING THE PASSAGE OF THE AFOREMENTIONED NORTHERN STREAM
SYSTEM...LAKE EFFECT TRAJECTORIES BECOME REESTABLISHED WITH MINOR
ACCUMS POSSIBLE IN THE NORTHWEST SNOWBELT. THE LES CONNECTION
APPEARS TO BE RATHER SHORT-LIVED ESPECIALLY FROM ERIE.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
THURSDAY FCST/DAY 3 WX LOOKS QUIET UNDER HIGH PRESSURE. ALL EYES
WILL TURN TO LOW PRESSURE SYSTEM DEVELOPING INTO THE TN VALLEY
AND SOUTHERN APPALACHIANS BY THURSDAY NIGHT.
THE PRIMARY IMPACTS THIS PERIOD WILL BE FOR GROWING CONFIDENCE IN
A MAJOR EAST COAST WINTER STORM INCLUDING HEAVY SNOW POTENTIAL IN
CENTRAL PENNSYLVANIA. EXPECT THE MODEL SPREAD WITH THIS SYSTEM TO
CONTINUE TO NARROW AS THE UPPER LEVEL FEATURE COMES ONSHORE OVER
THE PACIFIC NW TONIGHT. WHILE IT IS STILL TO EARLY TO GET INTO THE
SPECIFIC DETAILS...HERE ARE SOME EARLY GOAL POSTS:
PTYPE: MODEL CONSENSUS AT THIS TIME FAVORS SNOW AS THE PRIMARY
WINTER PTYPE NEAR AND NORTHWEST OF THE I-95 URBAN CORRIDOR
TIMING: GFS/CMC/WPC QPF WOULD SUGGEST A FRIDAY MORNING ONSET
SPREADING FROM SOUTH TO NORTH BY THE AFTERNOON. THE ECMWF IS
SLOWER.
DURATION: SNOW COULD LAST THROUGH SATURDAY BEFORE ENDING SATURDAY
NIGHT/EARLY SUNDAY MORNING.
GREATEST RISK FOR HEAVY SNOW: SOUTH-CENTRAL AND SOUTHEASTERN
ZONES OR ROUGHLY THE SOUTHEAST 1/2 TO 1/3 OF THE CWA. BLOWING AND
DRIFTING POSSIBLE.
IMPROVING CONDITIONS LIKELY ARE ON SUNDAY WITH HIGH PRESSURE
RETURNING TO THE AREA. TEMPERATURES ARE FCST TO TREND WARMER TO
NEAR NORMAL LEVELS BY MONDAY.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
PERSISTENT SNOW BAND REMAINS ACROSS THE NW MTNS. THIS CONTINUES TO
BRING IFR VSBYS TO BFD. NEAR TERM MDL DATA CONTINUES TO INDICATE LAKE
EFFECT PLUME WILL SHIFT SOUTH AFTER MIDNIGHT...FAVORING
PREDOMINANTLY IFR CONDS BTWN 05Z- 12Z. EXPECT FOR THESE CONDITIONS
TO REMAIN SO THROUGH THE EARLY MORNING HOURS. THE GUSTY FLOW
SHOULD CONTINUE THE LAKE EFFECT THROUGH THE MORNING. THE WINDS
SHOULD SHIFT TO THE NORTH...THOUGH THIS ALONE WILL NOT CEASE ANY
SHOWERS. HOWEVER...A BUILDING RIDGE WILL REDUCE INSTABILITY
ENOUGH TUESDAY AFTERNOON TO END SHOWER ACTIVITY AND ALLOW FOR
IMPROVING CONDITIONS.
IMPROVING CONDS AT KJST...THOUGH RADAR INDICATES A BAND OF SHOWERS
TO THE NORTH...THAT IF IT MOVES SOUTH COULD BRING BACK IFR
CONDITIONS TO JST. THIS COULD HAPPEN BETWEEN 06Z TO 09Z...HOWEVER
MVFR CONDITIONS SHOULD REMAIN DOMINATE THROUGH THIS TIMEFRAME
OUTSIDE ANY BRIEF PERIODS OF IFR IN PASSING SHOWERS. FOR THE REST
OF CENTRAL PA...THE DRYING EFFECT OF DOWNSLOPING WESTERLY FLOW
SHOULD YIELD VFR FLYING OVERNIGHT.
HIGH PRESSURE BUILDING IN FROM THE MIDWEST WILL CAUSE LAKE EFFECT
SNOW TO TAPER OFF ACROSS THE NW MTNS TUESDAY. HOWEVER...RESIDUAL
LOW LVL MOISTURE ASCENDING THE ALLEGHENIES SHOULD CAUSE MVFR
STRATOCU TO PERSIST INTO TUE EVENING AT KBFD AND KJST. AFTER A BIT
OF A LULL IN THE WINDS OVERNIGHT...EXPECT GUSTY WINDS TO REDEVELOP ACROSS
THE ENTIRE AREA FROM LATE AM THRU EARLY EVENING TUES...AS DIURNAL
HEATING/DEEPENING BLYR DEPTH ALLOW STRONGER WINDS TO MIX TO THE
SFC. BUFKIT SOUNDINGS SUPPORT GUSTS BTWN 25-30KTS TUE AFTN.
OUTLOOK...
WED...A BRIEF EVENING -SHSN/VIS REDUCTION POSSIBLE KJST/KBFD.
THU...NO SIG WX EXPECTED.
FRI...SNOW POSSIBLE...ESP SOUTH.
SAT...SNOW/WIND POSSIBLE...ESP SOUTH/EAST.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY UNTIL 10 AM EST THIS MORNING FOR PAZ024-
033.
&&
$$
SYNOPSIS...STEINBUGL
NEAR TERM...STEINBUGL
SHORT TERM...STEINBUGL
LONG TERM...STEINBUGL
AVIATION...FITZGERALD/CERU
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
457 AM EST TUE JAN 19 2016
.SYNOPSIS...
ACCUMULATING LAKE EFFECT SNOW WILL END THIS MORNING. LIGHT SNOW
IS POSSIBLE LATER WEDNESDAY. A MAJOR WINTER STORM COULD BRING
SIGNIFICANT SNOWFALL TO MUCH OF CENTRAL PA FRIDAY INTO SATURDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
MODELS DEPICT A STRONG LOBE OF VORTICITY SWINGING THROUGH PA BY
18Z. HRRR SHOWS LES BANDS WEAKENING THROUGH THE MORNING BEFORE
TAPERING OFF BY TONIGHT...AS INCREASINGLY ANTICYCLONIC LOW TO MID
LEVEL FLOW PUSHES ACROSS THE LAKES. WITH ONLY MINOR ADDITIONAL LES
ACCUMULATIONS EXPECTED...WILL ALLOW THE LES HEADLINES EXPIRE AS
SCHEDULED AT 12Z/7AM. WIND CHILL HAZARD ALSO ON TRACK TO EXPIRE AT
10AM AS MINIMUM WIND CHILLS TREND INTO THE NEGATIVE SINGLE DIGITS.
OVERALL IT WILL BE ANOTHER BRISK AND VERY COLD DAY WITH WIND
CHILLS IN THE SINGLE DIGITS +/- ZERO. WEAK RIDGING SURFACE AND
ALOFT SLIDES INTO THE AREA FROM THE OH VALLEY TONIGHT WITH NO
SIGNIFICANT WEATHER EXPECTED. LOWS WILL RANGE FROM THE POSITIVE
SINGLE DIGITS IN THE LAURELS TO THE MID TEENS ACROSS THE MID TO
LOWER SUSQUEHANNA VALLEY.
&&
.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/...
SPLIT FLOW TROUGH WILL MIGRATE QUICKLY EASTWARD FROM THE PLAINS TO
THE EAST COAST BY 21/1200Z. MODELS SHOW THE NORTHERN STREAM SYSTEM
BEING MORE AMPLIFIED AS IT TRACKS FROM THE MIDWEST THROUGH THE NRN
MID-ATLANTIC STATES. WITH MOISTURE LACKING...MODEST HEIGHT FALLS
COULD COMBINE WITH WEAK WAA TO BRING A PERIOD OF LIGHT SNOW OVER
THE ALLEGHENY RIDGES LATER WEDNESDAY INTO WEDNESDAY NIGHT. ANY
SNOW ACCUMS WOULD BE AN INCH OR LESS BASED ON BLENDED MEAN QPF.
FOLLOWING THE PASSAGE OF THE AFOREMENTIONED NORTHERN STREAM
SYSTEM...LAKE EFFECT TRAJECTORIES BECOME REESTABLISHED WITH MINOR
ACCUMS POSSIBLE IN THE NORTHWEST SNOWBELT. THE LES CONNECTION
APPEARS TO BE RATHER SHORT-LIVED ESPECIALLY FROM ERIE.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
THURSDAY FCST/DAY 3 WX LOOKS QUIET UNDER HIGH PRESSURE. ALL EYES
WILL TURN TO LOW PRESSURE SYSTEM DEVELOPING INTO THE TN VALLEY
AND SOUTHERN APPALACHIANS BY THURSDAY NIGHT.
THE PRIMARY IMPACTS THIS PERIOD WILL BE FOR GROWING CONFIDENCE IN
A MAJOR EAST COAST WINTER STORM INCLUDING HEAVY SNOW POTENTIAL IN
CENTRAL PENNSYLVANIA. EXPECT THE MODEL SPREAD WITH THIS SYSTEM TO
CONTINUE TO NARROW AS THE UPPER LEVEL FEATURE COMES ONSHORE OVER
THE PACIFIC NW TONIGHT. WHILE IT IS STILL TO EARLY TO GET INTO THE
SPECIFIC DETAILS...HERE ARE SOME EARLY GOAL POSTS:
PTYPE: MODEL CONSENSUS AT THIS TIME FAVORS SNOW AS THE PRIMARY
WINTER PTYPE NEAR AND NORTHWEST OF THE I-95 URBAN CORRIDOR
TIMING: GFS/CMC/WPC QPF WOULD SUGGEST A FRIDAY MORNING ONSET
SPREADING FROM SOUTH TO NORTH BY THE AFTERNOON. THE ECMWF IS
SLOWER.
DURATION: SNOW COULD LAST THROUGH SATURDAY BEFORE ENDING SATURDAY
NIGHT/EARLY SUNDAY MORNING.
GREATEST RISK FOR HEAVY SNOW: SOUTH-CENTRAL AND SOUTHEASTERN
ZONES OR ROUGHLY THE SOUTHEAST 1/2 TO 1/3 OF THE CWA. BLOWING AND
DRIFTING POSSIBLE.
IMPROVING CONDITIONS LIKELY ARE ON SUNDAY WITH HIGH PRESSURE
RETURNING TO THE AREA. TEMPERATURES ARE FCST TO TREND WARMER TO
NEAR NORMAL LEVELS BY MONDAY.
&&
.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
PERSISTENT SNOW BAND REMAINS ACROSS THE NW MTNS. THIS CONTINUES TO
BRING IFR VSBYS TO BFD. NEAR TERM MDL DATA CONTINUES TO INDICATE LAKE
EFFECT PLUME WILL SHIFT SOUTH AFTER MIDNIGHT...FAVORING
PREDOMINANTLY IFR CONDS BTWN 05Z- 12Z. EXPECT FOR THESE CONDITIONS
TO REMAIN SO THROUGH THE EARLY MORNING HOURS. THE GUSTY FLOW
SHOULD CONTINUE THE LAKE EFFECT THROUGH THE MORNING. THE WINDS
SHOULD SHIFT TO THE NORTH...THOUGH THIS ALONE WILL NOT CEASE ANY
SHOWERS. HOWEVER...A BUILDING RIDGE WILL REDUCE INSTABILITY
ENOUGH TUESDAY AFTERNOON TO END SHOWER ACTIVITY AND ALLOW FOR
IMPROVING CONDITIONS.
IMPROVING CONDS AT KJST...THOUGH RADAR INDICATES A BAND OF SHOWERS
TO THE NORTH...THAT IF IT MOVES SOUTH COULD BRING BACK IFR
CONDITIONS TO JST. THIS COULD HAPPEN BETWEEN 06Z TO 09Z...HOWEVER
MVFR CONDITIONS SHOULD REMAIN DOMINATE THROUGH THIS TIMEFRAME
OUTSIDE ANY BRIEF PERIODS OF IFR IN PASSING SHOWERS. FOR THE REST
OF CENTRAL PA...THE DRYING EFFECT OF DOWNSLOPING WESTERLY FLOW
SHOULD YIELD VFR FLYING OVERNIGHT.
HIGH PRESSURE BUILDING IN FROM THE MIDWEST WILL CAUSE LAKE EFFECT
SNOW TO TAPER OFF ACROSS THE NW MTNS TUESDAY. HOWEVER...RESIDUAL
LOW LVL MOISTURE ASCENDING THE ALLEGHENIES SHOULD CAUSE MVFR
STRATOCU TO PERSIST INTO TUE EVENING AT KBFD AND KJST. AFTER A BIT
OF A LULL IN THE WINDS OVERNIGHT...EXPECT GUSTY WINDS TO REDEVELOP ACROSS
THE ENTIRE AREA FROM LATE AM THRU EARLY EVENING TUES...AS DIURNAL
HEATING/DEEPENING BLYR DEPTH ALLOW STRONGER WINDS TO MIX TO THE
SFC. BUFKIT SOUNDINGS SUPPORT GUSTS BTWN 25-30KTS TUE AFTN.
OUTLOOK...
WED...A BRIEF EVENING -SHSN/VIS REDUCTION POSSIBLE KJST/KBFD.
THU...NO SIG WX EXPECTED.
FRI...SNOW POSSIBLE...ESP SOUTH.
SAT...SNOW/WIND POSSIBLE...ESP SOUTH/EAST.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
LAKE EFFECT SNOW WARNING UNTIL 7 AM EST THIS MORNING FOR
PAZ004-005.
WIND CHILL ADVISORY UNTIL 10 AM EST THIS MORNING FOR PAZ024-
033.
&&
$$
SYNOPSIS...STEINBUGL
NEAR TERM...STEINBUGL
SHORT TERM...STEINBUGL
LONG TERM...STEINBUGL
AVIATION...FITZGERALD/CERU
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
126 AM EST TUE JAN 19 2016
.SYNOPSIS...
A WESTERLY FLOW OF ARCTIC AIR WILL CAUSE LAKE EFFECT SNOWS ACROSS
NORTHWESTERN PENNSYLVANIA TONIGHT AND EARLY TUESDAY. HIGH
PRESSURE WILL THEN PROVIDE MAINLY DRY WEATHER THROUGH THURSDAY. A
SURFACE LOW WILL DEVELOP OVER THE DEEP SOUTH ON FRIDAY AND DEEPEN
AS IT MOVES NORTHEAST TO THE MID-ATLANTIC COAST. THIS STORM HAS
THE POTENTIAL TO BRING A WIDESPREAD SIGNIFICANT SNOWFALL TO THE
MID-ATLANTIC REGION.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
LAKE EFFECT SNOW ADVISORY CANCELLED FOR ELK CAMERON AND POTTER.
LAKE EFFECT SNOW WARNINGS CONTINUE FOR WARREN AND MCKEAN...AS WELL
AS WIND CHILL ADVISORIES FOR CAMBRIA AND SOMERSET.
UPSLOPE FLOW INTO THE WEST CENTRAL AND NORTHWEST MOUNTAINS IS
MAINTAINING NEARLY CONSTANT BUT LIGHT 1-2SM -SN IN THE WRN AND
NORTHWEST MTNS. SNOWBANDS HAVE SHIFTED SOUTH THIS EVENING BACK
OVER THE LE WARNING AREA. LATEST HRRR CONTINUES TO INDICATE THAT
THESE WILL SAG SOUTHWARD IN THE BACKING FLOW OVERNIGHT. WILL ADD
TO EARLIER TOTALS OVERNIGHT AS A RESULT...AND THUS LAKE EFFECT
WARNINGS CONTINUE.
WIND CHILL ADVY STILL SOLID IN THE ADVY AREA AND TEMPS GETTING
COLDER TONIGHT. MINS WILL GET INTO THE SINGLE DIGITS FOR MUCH OF
THE AREA...WITH DOUBLE DIGITS HERE AND THERE - MAINLY IN THE
VALLEYS OF THE EAST. SOME SOTS IN THE LAURELS LIKE MEYERSDALE
COULD GET BELOW 0F AIR TEMP.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM WEDNESDAY/...
HIGHEST MOISTURE DISSIPATES IN PLACE ON TUESDAY AFTER THE PASSAGE
OF A STRONG VORT MAX AROUND SUNRISE. BUT SOME UPSLOPE/FLURRIES
MAY LINGER IN THE LAURELS FOR THE MORNING AND SHSN IN THE NW FOR
MUCH OF THE DAY DUE TO FAVORABLE FETCH AND TEMPS. HOWEVER...THE
SIG ACCUMS SHOULD BE TAPERING OFF IN THE MORNING. SUBSIDENCE
SHOULD HELP TO SQUASH THE VERTICAL MOTION/INSTABILITY. WARNING
ONLY GOES UNTIL 12Z...EXP TIMING THERE S/B FINE EVEN IF SOME LIGHT
ACCUMS LINGER. THE WORST OF IT WILL BE OVER BY THEN. WILL LINGER
CLOUDS ACROSS THE N FOR MOST OF THE DAY. MAXES SHOULD BE 2-7F
MILDER THAN TODAY WITH MORE SUN AND SLIGHTLY HIGHER 8H TEMPS AND
MIXING. WIND CHILLS WILL INCREASE SLIGHTLY AS THE TEMPS DO. THIS
SHOULD ALLOW THE WC ADVY TO EXPIRE.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
POTENTIAL WINTER STORM COULD BRING IMPACTS TO CENTRAL PA FRI INTO
SAT NIGHT.
1035MB SURFACE HIGH STRETCHING FROM THE UPPER MIDWEST THROUGH THE
OHIO VALLEY WILL WEAKEN SOMEWHAT AS IT SPREADS INTO THE AREA LATE
TUESDAY...AHEAD OF A WEAKENING AND MOISTURE-CHALLENGED ALBERTA
CLIPPER WHICH WILL BRING A CHANCE OF LIGHT SNOW SHOWERS TO MAINLY
WESTERN SECTIONS WEDNESDAY NIGHT...WITH ONLY MINOR ACCUMULATIONS
EXPECTED.
HIGH RE-ESTABLISHES OVER CENTRAL PA THU...THOUGH THIS TIME ONLY
IN THE 1024-1028MB RANGE...AND RETREAT NORTHWARD ON FRI. AT THE
SAME TIME...LOW PRESSURE EXPECTED TO DEEPEN OVER SOUTHERN
APPALACHIANS AND MOVE ACROSS MID-ATLANTIC STATES FRI NIGHT AND
SAT. THOUGH POTENTIAL WINTER STORM REMAINS SEVERAL DAYS OUT...AND
SHORTWAVE ENERGY AT THIS TIME REMAINS WELL OUT OVER THE PACIFIC
OCEAN...MOST EXTENDED MODEL GUIDANCE APPEARS TO BE LATCHING ON TO
AND TRACKING IT FAIRLY WELL. THE WAVE SHOULD ARRIVE ON THE PACIFIC
COAST TUE NIGHT AND DROP INTO THE CENTRAL PLAINS ON THU. COMBO OF
THE EARLIER-IN-THE-WEEK CLIPPER AND THIS WAVE CARVE OUT A
SHARPENING TROUGH FOR THE EAST COAST LATE WEEK AS RIDGE FORMS OVER
THE ROCKIES. LATEST 12Z GEFS AND OPERATIONAL GFS REVEAL NO BIG
CHANGES WITH 12Z ECMWF HUGGING THE MID ATLANTIC COAST A BIT
LONGER...THOUGH THIS FAR OUT THE MODELS STILL OVERALL APPEAR IN
FAIRLY GOOD BASIC AGREEMENT WITH TIMING AND TRACK OF LOW
PRESSURE AS IT STRENGTHENS.
BASED ON MODEL CONSENSUS THIS FAR OUT...THERE CONTINUES TO BE
MEDIUM CONFIDENCE FOR A SIGNIFICANT WINTER STORM OVER THE MID
ATLANTIC AND NORTHEAST FRIDAY AFTERNOON THROUGH SATURDAY...
WITH BIGGEST POTENTIAL IMPACTS TO CWA BEING ROUGHLY THE SOUTHEAST
HALF. CONSENSUS PTYPE IS SNOW...WITH PLENTY OF COLD AIR IN
PLACE. KEEP IN MIND THAT OBVIOUSLY IT/S STILL FAR TOO EARLY TO
SAY FOR CERTAIN 4-5 DAYS OUT...ESPECIALLY WHEN THE WAVE DRIVING
THIS ISN/T EVEN TO THE WEST COAST YET. THERE ARE STILL A LOT OF
VARIABLES IN PLAY THAT COULD IMPACT THE EVOLUTION OF THIS SYSTEM.
LOOKING PAST THE STORM AFTER IT MOVES AWAY SAT NIGHT AND
SUNDAY...PACIFIC HIGH PRESSURE LOOKS TO BUILD INTO THE REGION
PROVIDING GENERALLY FAIR AND MILDER CONDS THAN WE WILL SEE FOR
MOST OF THIS WEEK. A CLIPPER MAY BRING ANOTHER ROUND OF LIGHT SNOW
TO THE NORTH AND WEST EARLY NEXT WEEK.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
PERSISTENT SNOW BAND REMAINS ACROSS THE NW MTNS. THIS CONTINUES TO
BRING IFR VSBYS TO BFD. NEAR TERM MDL DATA CONTINUES TO INDICATE LAKE
EFFECT PLUME WILL SHIFT SOUTH AFTER MIDNIGHT...FAVORING
PREDOMINANTLY IFR CONDS BTWN 05Z- 12Z. EXPECT FOR THESE CONDITIONS
TO REMAIN SO THROUGH THE EARLY MORNING HOURS. THE GUSTY FLOW
SHOULD CONTINUE THE LAKE EFFECT THROUGH THE MORNING. THE WINDS
SHOULD SHIFT TO THE NORTH...THOUGH THIS ALONE WILL NOT CEASE ANY
SHOWERS. HOWEVER...A BUILDING RIDGE WILL REDUCE INSTABILITY
ENOUGH TUESDAY AFTERNOON TO END SHOWER ACTIVITY AND ALLOW FOR
IMPROVING CONDITIONS.
IMPROVING CONDS AT KJST...THOUGH RADAR INDICATES A BAND OF SHOWERS
TO THE NORTH...THAT IF IT MOVES SOUTH COULD BRING BACK IFR
CONDITIONS TO JST. THIS COULD HAPPEN BETWEEN 06Z TO 09Z...HOWEVER
MVFR CONDITIONS SHOULD REMAIN DOMINATE THROUGH THIS TIMEFRAME
OUTSIDE ANY BRIEF PERIODS OF IFR IN PASSING SHOWERS. FOR THE REST
OF CENTRAL PA...THE DRYING EFFECT OF DOWNSLOPING WESTERLY FLOW
SHOULD YIELD VFR FLYING OVERNIGHT.
HIGH PRESSURE BUILDING IN FROM THE MIDWEST WILL CAUSE LAKE EFFECT
SNOW TO TAPER OFF ACROSS THE NW MTNS TUESDAY. HOWEVER...RESIDUAL
LOW LVL MOISTURE ASCENDING THE ALLEGHENIES SHOULD CAUSE MVFR
STRATOCU TO PERSIST INTO TUE EVENING AT KBFD AND KJST. AFTER A BIT
OF A LULL IN THE WINDS OVERNIGHT...EXPECT GUSTY WINDS TO REDEVELOP ACROSS
THE ENTIRE AREA FROM LATE AM THRU EARLY EVENING TUES...AS DIURNAL
HEATING/DEEPENING BLYR DEPTH ALLOW STRONGER WINDS TO MIX TO THE
SFC. BUFKIT SOUNDINGS SUPPORT GUSTS BTWN 25-30KTS TUE AFTN.
OUTLOOK...
WED...A BRIEF EVENING -SHSN/VIS REDUCTION POSSIBLE KJST/KBFD.
THU...NO SIG WX EXPECTED.
FRI...SNOW POSSIBLE...ESP SOUTH.
SAT...SNOW/WIND POSSIBLE...ESP SOUTH/EAST.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
LAKE EFFECT SNOW WARNING UNTIL 7 AM EST THIS MORNING FOR
PAZ004-005.
WIND CHILL ADVISORY UNTIL 10 AM EST THIS MORNING FOR PAZ024-
033.
&&
$$
SYNOPSIS...DANGELO
NEAR TERM...DANGELO/DEVOIR
SHORT TERM...DANGELO
LONG TERM...RXR
AVIATION...FITZGERALD/CERU
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1058 PM CST MON JAN 18 2016
.UPDATE...
ISSUED AT 854 PM CST MON JAN 18 2016
THE 00Z NAM HAS BEGUN TO COME IN AND IT IS DIGGING THE UPPER WAVE
CURRENTLY OVER MONTANA FARTHER SOUTH AS IT MOVES INTO THE EASTERN
PLAINS. THIS PUTS THE STRONGEST FORCING FOR ASCENT INTO EASTERN
NEBRASKA MORE QUICKLY. WITH ONLY WEAK LIFT OVER MUCH OF SOUTHWEST
MINNESOTA AND EAST CENTRAL SOUTH DAKOTA...IT IS GOING TO TAKE
LONGER TO OVERCOME THE LOW LEVEL DRY AIR. BOTH THE OPERATIONAL AND
EXPERIMENTAL HRRR AS WELL AS THE RAP NOW HAVE SNOW REACHING SIOUX
CITY BETWEEN 6 AND 8 AM AND SIOUX FALLS BETWEEN 8 AM AND 11 AM.
GIVEN PROGRESSION OF UPPER WAVE...THAT SEEMS REASONABLE AND HAVE
SLOWED SNOW PROGRESSION TO THE EAST. THIS MEANS A LITTLE LESS SNOW
FOR I-29 CORRIDOR NORTH OF BERESFORD WITH SNOWFALL NOW EXPECTED TO
BE CLOSER TO AN INCH THAN TWO INCHES.
UPDATED GRIDS AVAILABLE SHORTLY.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 313 PM CST MON JAN 18 2016
STRATUS SHIELD ACROSS THE NORTHEAST HALF OF THE CWA WAS SLOWER TO
CLEAR/THIN TODAY THAN EXPECTED...BUT APPEARS THAT IT IS ON ITS WAY
BASED ON SCATTERING REPORTED IN SURFACE OBSERVATIONS OVER THE PAST
HOUR OR TWO. STILL ON THE CLOUDIER SIDE THIS AFTERNOON THOUGH...WITH
THICKER HIGH CLOUDS SPILLING INTO THE REGION IN ADVANCE OF SYSTEM
SET TO AFFECT THE AREA TONIGHT/TUESDAY.
THIS SYSTEM NOW MOVING OUT OF THE NORTHERN ROCKIES AND IS SLATED TO
SLIDE ACROSS THE PLAINS AS TONIGHT THROUGH TUESDAY EVENING. LEADING
MID LEVEL WARM FRONT RESPONSIBLE FOR THE THICKER CLOUDS WILL HAVE
LITTLE IMPACT ON SNOW DEVELOPMENT. AS SOUTHERN PORTION OF THE WAVE
DIGS MORE STRONGLY INTO THE SOUTHERN PLAINS...MODELS CONSISTENT IN
SHOWING AN INCREASE IN MID-LEVEL FRONTOGENESIS JUST SOUTH OF OUR
FORECAST AREA BY 12Z TUESDAY...AND THINK THIS WILL BE THE PRIMARY
FOCUS FOR HEAVIER SNOWFALL POTENTIAL AS THAT WAVE SWINGS THROUGH THE
CENTRAL PLAINS. STILL EXPECTING BROAD SWATH OF SNOW EXTENDING NORTH
THROUGH OUR AREA AS WEAKER/NORTHERN PORTION OF THE WAVE MOVES ACROSS
THE DAKOTAS INTO MINNESOTA. HOWEVER WITH FRONTAL FOCUS TO OUR SOUTH
AND SOUNDINGS INDICATING DEEP DRY LAYER WHICH WILL DELAY ONSET OF
ACCUMULATING SNOW A BIT...LOOKS LIKE SNOWFALL AMOUNTS IN OUR AREA
WILL BE A LITTLE LIGHTER THAN PREVIOUSLY FORECAST. STILL GOING FOR
AMOUNTS WITHIN THE 1-3 INCH RANGE FOR CWA...LIGHTEST IN AREAS NORTH
OF I-90 AND ESPECIALLY IN SOUTHWEST MN WHERE DRY LAYER PERSISTS THE
LONGEST.
TEMPERATURES TONIGHT ARE A LITTLE TRICKY AS MANY AREAS WARMED INTO
THE HIGHER END SINGLE DIGITS TO AROUND 10F...AND MANY MODELS DO NOT
HAVE A GREAT HANDLE ON THIS. WILL STILL SEE A DROPOFF IN TEMPS THIS
EVENING BEFORE LOW-MID CLOUDS BEGIN TO THICKEN/PUSH EAST...BUT MAIN
QUESTION IS HOW MUCH. HEDGES TOWARD WARMER END OF AVAILABLE GUIDANCE
NUMBERS...WHICH STILL DROPS FAR EASTERN CWA BACK BELOW ZERO DURING
THE EVENING BEFORE REBOUNDING TO NEAR/ABOVE ZERO BY DAYBREAK. AREAS
FARTHER WEST WILL LIKEWISE SEE EVENING LOWS...FOLLOWED BY STEADY TO
RISING TEMPERATURES LATE TONIGHT. SHOULD CONTINUE TO SEE A SLOW BUT
STEADY CLIMB INTO THE TEENS-LOWER 20S FOR HIGHS TUESDAY...WHICH MAY
SEEM LIKE A HEAT WAVE AFTER THE FRIGID WEEKEND WE JUST HAD.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 313 PM CST MON JAN 18 2016
LINGERING LIGHT SNOW WILL EXIT THE AREA TO THE EAST QUICKLY TUESDAY
EVENING AND AM LIMITING MENTION TO ONLY THE FIRST THREE HOURS OF
TUESDAY NIGHT. IT IS POSSIBLE THERE COULD BE FLURRIES A BIT LONGER
WITH LINGERING STRATUS...BUT ON THE OTHER HAND CAN SEE THE SNOW
ENDING BY 6PM...WHICH OF COURSE IS REFLECTED IN ONLY CHANCE POPS FAR
EAST FOR THAT EARLY EVENING. THE LINGERING STRATUS SHOULD CLEAR OUT
EVENTUALLY TO THE EAST AND NORTHEAST BUT HAVE GONE SLOWLY AS THERE
IS UNCERTAINTY IN STRATUS CLEARING OUT AT NIGHT IN A SOUTHERLY FLOW.
ADD THAT TO THE LIKELIHOOD OF IT REDEVELOPING BY WEDNESDAY NIGHT AS
A WEAK INVERTED TROUGH MOVES TOWARD THE AREA. PARTLY TO MOSTLY
CLOUDY COULD BE TOO BRIGHT FOR A WEDNESDAY FORECAST...BUT WILL GO
WITH THAT FOR NOW.
TUESDAY NIGHT AND WEDNESDAY SHOULD BE A BIT WARMER WITH HIGHS
WEDNESDAY IN THE 20S TO LOWER 30S...STRATUS OR NOT.
ALONG WITH POSSIBLE STRATUS REDEVELOPMENT WEDNESDAY NIGHT...A WEAK
NORTHERN BRANCH SHORT WAVE COULD BRING A LITTLE LIGHT SNOW SOUTH...
MAINLY TO THE MISSOURI RIVER AREA. THIS WAVE IS NOT ONLY WEAK BUT
WEAKENING FURTHER AS A STRONGER WAVE DIVES WELL SOUTH OF THE AREA TO
DEVELOP A SYSTEM THAT SHOULD KEEP PEOPLE IN THE EAST BUSY FOR A FEW
DAYS. THERE COULD BE A LITTLE LIGHT SNOW OR FLURRIES LINGER THURSDAY
IN THE CONTINUING LOW LEVEL MOISTURE AND CLOUD COVER BUT SUPPORT IS
HARD TO FIND AND WILL LEAVE IT MOSTLY CLOUDY WITHOUT PRECIPITATION
FOR NOW.
A FEW DEGREES OF COOLING IS EXPECTED THURSDAY BEHIND THE WEAK
TROUGH...BUT CERTAINLY NO RETURN TO THE ARCTIC COLD OF THE WEEKEND.
FRIDAY THROUGH SUNDAY SHOULD BRING MILDER TEMPERATURES AS UPPER
RIDGING ARRIVES IN THE CENTRAL PLAINS THEN IS FLATTENED A LITTLE BY
ANOTHER WEAK SHORT WAVE. THIS WEAK SHORT WAVE COULD BRING A LITTLE
LIGHT SNOW FOR SUNDAY...BUT AGAIN NOTHING TO GET VERY EXCITED ABOUT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1058 PM CST MON JAN 18 2016
MAIN CONCERN CONTINUES TO BE SNOW LATER TONIGHT AND TOMORROW. MAIN
CHANGE TO FORECAST HAS BEEN TO SLOW DOWN THE ARRIVAL OF THE SNOW
ESPECIALLY AT KFSD. APPEARS SNOW WILL NOT ARRIVE UNTIL 15Z OR 16Z
AND WITH DRY AIR TO OVERCOME...VSBYS WILL PRIMARILY BE FROM 2 TO 4
MILES. STILL EXPECT 1 MILE VSBY AT KSUX WITH CIGS BELOW 2000 FT
FROM MID MORNING TO MOD AFTERNOON. AS BEFORE...COULD SEE VSBYS
BELOW 1 SM AT KSUX BUT DURATION LOOKS TO BE MAYBE AN HOUR OR TWO
AND COULD BE INTERMITTENT SO DECIDED TO KEEP WITH IFR CONDITIONS
ONLY. ONCE SNOW ENDS...VSYBS SHOULD IMPROVE BUT CIGS WILL STAY
AROUND 2000 FT THROUGH 06Z WEDNESDAY.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
UPDATE...SCHUMACHER
SHORT TERM...JH
LONG TERM...
AVIATION...SCHUMACHER
Area Forecast Discussion
National Weather Service Spokane WA
354 PM PST WED JAN 20 2016
.SYNOPSIS...
A slow moving frontal system will bring locally heavy snow to the
Cascades and the Methow Valley tonight into Thursday. The front
will gradually move through eastern Washington and north Idaho on
Friday bringing light rain. Saturday will also feature the
potential for rain and mountain snow. High pressure should produce
mainly dry conditions Sunday and Monday before more valley rain
and mountain snow returns Tuesday.
&&
.DISCUSSION...
...HEAVY MOUNTAIN SNOW AND WINTRY MIX EAST SLOPES OF CASCADES
TONIGHT THROUGH FRIDAY MORNING...
Tonight through Friday morning: Satellite imagery shows the next
weather system knocking on our doorstep. The upper level low
pressure circulation is located out at 50N 135W in the Gulf of
Alaska. This low pressure system is tapping into a sub-tropical
moisture plume that extends out to the Hawaiian Islands. The
upper level trough will continue to dig as it approaches the
region. This will act to orient the moisture plume more
meridionally more along the western coast line. The warm front
currently pushing its way into northwest OR with light rain being
observed on radar along the coast. This front is progged to reach
the northern Cascades between 8:00 and 10:00 PM this evening based
off the latest HRRR guidance. Much of the region will see at least
a chance for some light precipitation as the front crosses eastern
WA and into the ID Panhandle overnight.
A southeasterly pressure gradient will strengthen overnight. This
will result in some downsloping off of the Northeast Blue Mtns and
off of the higher terrain in the ID Panhandle. I anticipate that
that this will act to hinder much precipitation from actually
reaching the ground across the Palouse, into the Lewiston-
Clarkston Vly and up on the Camas Prairie. Generally only some
light precipitation is anticipated with the warm front across much
of eastern WA and in the ID Panhandle.
Areas that will benefit from the easterly gradient will be the
East Slopes of the Northern Cascades. The combination of moist
isentropic ascent and orographics should keep these areas wet.
Snow levels are going to be very tricky with this system.
Valleys that saw some sun across this area this afternoon should
have a difficult time cooling back down below freezing overnight.
Higher clouds are already moving in and this should act to keep
this warmer air from radiating completely away. However, the
Okanogan Valley and Methow Valley continue to see low clouds,
which has kept their temperatures down in the low 30s. These
locations will see a better chance for accumulating snow;
although, I am not as confidence about the Okanogan Valley. I
think surface temperatures will be too warm for much of the
Wenatchee Area for snow to stick, especially right along the
Columbia River. I also think that Wenatchee River Valley, Entiat
River Valley and communities along Lake Chelan will have a
difficult time seeing snow accumulate. The Winter Storm Watch will
be upgraded to a Warning for heavy snow, but will largely only
includes locations below 3000 feet south of Lake Chelan. The upper
reaches of the Methow Valley will also see a good chance for heavy
snow accumulations. The warning will run from tonight and continue
into Friday morning until the cold front passes through. I also
kept a possibility for freezing rain in the east slopes of the
northern Cascades and colder pockets in the Wenatchee Area. My
confidence is low since way did see some warming today, but cannot
completely rule it out. /SVH
Friday: The frontal system hung up along the Cascades Thursday and
Thursday night will finally be shoved eastward on Friday. There
will be a good deal of deep layer moisture accompanying the front
as it moves through eastern Washington and north Idaho, but not a
lot of large scale forcing. The models hardly depict a surface low
with the weak 500mb shortwave trough...an indication of weak
forcing. So despite an abundance of moisture, precipitation
amounts will be relatively light compared to some of our recent
storm systems. Snow levels will be high Friday and Friday night
with lowland communities region-wide receiving rain. One area of
exception could be the Methow Valley where the NAM and GFS depict
a bit of cooler air trapped along the Cascades which could
contribute to light snow accumulations Friday morning.
Saturday and Sunday: Saturday has the potential to be cool and wet
as a weakening upper low moves into Oregon and falls apart. The
GFS and Canadian models sustain a weak deformation band Saturday
into Saturday night which produces a tenth to a quarter of an inch
or precipitation for eastern Washington and north Idaho. The NAM
and ECMWF split this feature suggesting lower precipitation
chances for our region Saturday. This system bears watching since
snow levels will be marginal for accumulations in the lee of the
Cascades into portions of Washington and Idaho near the Canadian
border. However, given the daytime arrival of precipitation, snow
may struggle to accumulate on roads. There is good model agreement
that Sunday will be drier with orographic snow showers mainly
limited to the mountains of the Idaho Panhandle. The sun may even
make an appearance Sunday along the east slopes of the Cascades
into portions of the Columbia Basin. /GKoch
Sunday night through Wednesday...Models are in good agreement of
an upper level ridge over the region Sunday night through Monday
night. This should result in dry conditions with areas of low
clouds and patchy fog in the valleys and Columbia Basin. The ridge
moves east on Tuesday allowing a weak short wave trough to pass
through the Inland NW bringing with it a chance for light rain and
snow. GFS Ensembles show quite a bit of spread regarding the
timing of this wave and would not be surprised to see the timing
delayed until Tuesday night or Wednesday. Models then show a
milder and wetter system for next Wednesday or Thursday. Near to
slightly above normal temperatures are expected in the extended
forecast period. JW
&&
.AVIATION...
00Z TAFS: A warm front will bring our next round of precipitation
to the Inland Northwest tonight into Thursday. Precipitation may
begin as light snow at Wenatchee, Coeur d`Alene, and Chelan, but
should transition to rain. As with most moist frontal systems this
time of year, precipitation will likely be accompanied by low
clouds and visibility restrictions especially in the 12z-20z time
frame. /GKoch
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 34 42 36 42 33 39 / 20 50 20 60 40 50
Coeur d`Alene 33 41 35 42 33 39 / 10 50 20 70 50 50
Pullman 35 46 38 46 34 40 / 10 20 10 60 40 50
Lewiston 36 51 41 50 37 44 / 10 20 10 30 30 50
Colville 32 39 34 40 33 37 / 30 80 50 60 40 40
Sandpoint 32 38 35 40 33 38 / 20 60 20 80 60 50
Kellogg 31 40 36 40 31 36 / 10 40 20 70 60 60
Moses Lake 34 43 34 44 32 40 / 30 50 30 40 20 50
Wenatchee 34 39 35 42 31 37 / 90 90 80 90 20 50
Omak 32 36 33 39 29 35 / 70 100 80 90 20 40
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Winter Storm Warning from 10 PM this evening to 10 AM PST Friday
for East Slopes Northern Cascades.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
533 PM CST WED JAN 20 2016
.SHORT TERM...(TONIGHT THROUGH THURSDAY)
ISSUED AT 212 PM CST WED JAN 20 2016
FAIRLY QUIET WEATHER OVER NEXT 24 HOURS AS SOUTHERN FLOW BECOMES
MORE DOMINANT WEATHER PRODUCER. AS ONE SHORT WAVE TROUGH EXITS THE
GREAT LAKES...ANOTHER MINOR WAVE IS TRACKING ACROSS CENTRAL CANADIAN
PRAIRIES. BUT MAIN ENERGY IS STRONGER SHORT WAVE THAT IS ALIGNING
ENERGY IN SOUTHERN PLAINS AND WILL PASS BY TO THE SOUTH.
SURFACE RIDGE WILL EDGE OFF TO THE EAST BUT LOOKS LIKE PLENTY OF
CLOUDS WILL PERSIST BETWEEN THESE SYSTEMS. SOUTH TO SOUTHEAST LOW
LEVEL FLOW AROUND EXITING HIGH WILL LIKELY KEEP TEMPERATURES FROM
FALLING MUCH THIS EVENING. PREFER IDEA OF WARMER LOWS AND TRIED TO
STAY ABOVE GUIDANCE. COULD ALSO SEE SOME AREAS OF FOG DEVELOP IN
WARM AIR ADVECTION BUT WITH MINIMAL IMPACT...WILL NOT INCLUDE AT
THIS TIME.
AS MAIN STORM TRACKS BY TO THE SOUTH TOMORROW...WEAK CHANNEL OF
VORTICITY ALONG WITH SUBTLE LIFT OF CANADIAN WAVE COULD PRODUCE
ENOUGH FORCING TO DEVELOP SOME LIGHT SNOW LATE IN THE
DAY...SPREADING IN FROM THE WEST. GFS HAS BEEN A LITTLE FASTER
BRINGING THIS SNOW IN BUT PREFER BLEND OF ECMWF AND NAM THAT
INCREASES SNOW THREAT LATE IN THE DAY. EITHER WAY...DID RAISE
OVERALL SNOW CHANCES...ESPECIALLY ACROSS SOUTHERN MINNESOTA.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 212 PM CST WED JAN 20 2016
WEAK WAVE AND FORCING MENTIONED IN SHORT TERM DISCUSSION WILL
CONTINUE TO PRODUCE SOME LIGHT SNOW INTO THURSDAY NIGHT. 20.12Z NAM
SOUNDINGS SUGGEST FAIRLY GOOD LIFT NEAR DENDRIDIC ZONE SO SNOW LOOKS
AT LEAST LIKELY FOR A PERIOD. LOWER QPF AMOUNTS SUGGEST VERY MINOR
ACCUMULATIONS. FORCING A BIT STRONGER WEST OF THE MISSISSIPPI RIVER
AND WEAKENING OVERNIGHT AS WAVE MOVES EAST...SO ALIGNED SLIGHTLY
HIGHER SNOW AMOUNTS THERE AND MUCH LIGHTER TO THE EAST...ALONG WITH
LOWER CHANCES OVERALL.
AFTER THAT UPPER RIDGE BEGINS TO BUILD BACK IN FOR WEEKEND...AS MID
ATLANTIC REGION BRACES FOR WINTER STORM. WARMING TREND ON TRACK FOR
THAT PERIOD AS SUN AND WARMER AIR RETURNS.
BY SUNDAY NIGHT AND MONDAY...SHORT WAVE ENERGY EJECTS OUT OF THE
WEST BUT SOME QUESTIONS THAT FAR OUT ON HOW ORGANIZED SYSTEMS COULD
BE. SEEMS LIKE NEXT PRECIPITATION THREAT THOUGH AS YET ANOTHER SHOT
OF COLD AIR DROPS IN AS UPPER RIDGE RETROGRADES WEST. AIRMASS NOT
NEARLY AS COLD AS PREVIOUS ARCTIC PLUNGE THOUGH BUT SHORT COOL OFF
BEFORE MODERATION TAKES PLACE LATE NEXT WEEK.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 533 PM CST WED JAN 20 2016
THE SURFACE RIDGE AXIS HAS MOVED EAST OF THE AREA ALLOWING A WEAK
SOUTHERLY FLOW TO SET UP OVER THE REGION. AN MVFR CLOUD DECK HAS
ALREADY SPREAD OVER BOTH SITES IN THIS PATTERN AND LOOKING AT THE
20.18Z AND 20.21Z RAP FORECAST SOUNDINGS...IT LOOKS LIKE IT WILL
BE STICKING AROUND THROUGH THE PERIOD. SOME IFR CEILINGS OVER
SOUTHWESTERN MINNESOTA AND EXPECT THAT THESE WILL MOVE OVER KRST
TONIGHT. SHOULD ALSO SEE SOME FOG DEVELOP TO TAKE THE VISIBILITY
DOWN TO MVFR AT KRST AS WELL. THE WINDS WILL REMAIN LIGHT THROUGH
THURSDAY...SO NOT REALLY SEEING ANYTHING THAT WOULD MAKE THE FOG
DISSIPATE ONCE IT DEVELOPS. A SYSTEM APPROACHING FROM THE
NORTHWEST WILL START TO BRING SOME LIGHT SNOW INTO MINNESOTA
THURSDAY AFTERNOON...BUT IT DOES NOT LOOK LIKE IT WILL SPREAD OVER
EITHER TAF SITE UNTIL THURSDAY EVENING.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...SHEA
LONG TERM...SHEA
AVIATION...04
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
351 AM EST THU JAN 21 2016
.DISCUSSION...
...COLD FRONT WILL BRING A CHANCE OF STORMS FRIDAY...
...WINDY AND MUCH COOLER BEHIND THE FRONT ON SATURDAY...
TODAY-TONIGHT...
RAOB SOUNDINGS FROM THE 21/00Z RELEASE CONTINUE TO SHOW A DEEP MID
LYR SUBSIDENCE INVERSION ACRS THE PENINSULA...THOUGH SIGNIFICANT
EROSION HAS OCCURRED OVER THE PAST 24HRS. RAP ANALYSIS STILL
INDICATING VERY WEAK H85-H70 LAPSE RATES BTWN 2.0-3.0C/KM ALONG OVER
MOST OF CENTRAL FL...BLO 2.0C/KM E OF LAKE OKEECHOBEE. A WEAK RIDGE
AXIS OVER ERN GOMEX/SW ATLC WILL THE BE THE PRIMARY WX FEATURE FOR
CENTRAL FL TODAY AS IT KEEP SIGNIFICANT DRY AIR REMAINS IN PLACE
ALOFT.
THE DRY AIR WILL MODIFY AS THE RIDGE PUSHES INTO THE W ATLC AND
COLLAPSE...BUT WITH PWAT VALUES OVER THE CENTRAL/NRN PENINSULA AOB
0.50"...MODIFICATION WILL REQUIRE SOME TIME...ESPECIALLY CONSIDERING
MEAN RH THRU THE H100-H70 LYR IS AOB 70PCT CLEAR DOWN TO CUBA AND
THE YUCATAN PENINSULA.
LGT/VRBL WINDS THRU DAYBREAK WILL SHIFT TO A LIGHT TO GENTLE ERLY
BREEZE BY MIDDAY...THE TO A GENTLE TO MODERATE SE BREEZE BY LATE
AFTN AS THE RIDGE DRIFTS OFFSHORE. WINDS WILL CONTINUE TO SHIFT TO
THE S/SE OVERNIGHT AS THE NEXT STORM SYSTEM CROSSES THE LWR MS
VALLEY AND DVLPS OVER THE DEEP SOUTH. TEMPS WILL BE NOTICEABLY WARMER
WITH THE DVLPG ONSHORE/SRLY WIND COMPONENT. AFTN MAXES IN THE L/M70S
WILL BE WITHIN A DEG OR TWO OF CLIMO AVG. ABV AVG MIN TEMPS
OVERNIGHT WITH READINGS IN THE M/U50S W OF I-95...U50S/M60S ALONG
THE COAST.
FRI...THE 00Z GFS SHOWED A DEEPENING SURFACE LOW OVER NORTHEAST
MISSISSIPPI AT 12Z FRI WITH A FAST MOVING COLD FRONT PIVOTING
AROUND IT IN THE EASTERN GULF OF MEXICO. A NARROW SWATH OF HIGHER
MOISTURE WITH SURFACE DEW POINTS INTO THE 60S IS FORECAST AHEAD OF
THE COLD FRONT SO EXPECT DEEP CONVECTION TO BE ONGOING IN THE GULF
AT THE START OF THE PERIOD. SINCE THIS RUN OF THE GFS SHOWS A
STRONGER SYSTEM...THE ASSOCIATED SQUALL LINE IS FORECAST TO SWEEP
ACROSS THE LOCAL AREA EARLIER...IN THE MORNING AND EARLY
AFTERNOON. THE NAM IS SLOWER BUT THE ECMWF IS CLOSER TO THE GFS
TIMING. HENCE...CANNOT OPT FOR THE SLOWER NAM SOLUTION.
A STRONG ATMOSPHERIC WIND PROFILE IS A GIVEN WITH THIS SYSTEM...
THOUGH NOT NEARLY AS STRONG AS WITH THE LAST SYSTEM. THE MAIN
FORECAST PROBLEM...LIKE IT USUALLY IS DURING OUR SEVERE WEATHER
SEASON...IS INSTABILITY. THE FASTER PROGRESSION OF THE COLD FRONT
WOULD PROVIDE FOR LIMITED INSTABILITY.
IN ANY EVENT...WE CAN EXPECT A FAST MOVING SQUALL LINE TO SWEEP
ACROSS THE AREA. WITH THE 925-850 MB WINDS 35-45 KNOTS...THERE IS
A CHANCE FOR STRONG WIND GUSTS WITH THE FAST MOVING CELLS. POPS
FROM ALL THE MODELS ARE 70-90 PERCENT SO HAVE NUDGED UP AREAWIDE
POPS CLOSER TO 80 PERCENT.
FRIDAY NIGHT...COLD FRONT WILL SWEEP EAST OF THE STATE BY EARLY
EVENING. BREEZY TO WINDY CONDITIONS EXPECTED BEHIND THE FRONT WITH
TIGHT PRESSURE GRADIENT AS DEEPENING LOW MOVES NORTHEAST ALONG THE
CAROLINA COAST. STEEP LOW LEVEL LAPSE RATES IN THE WAKE OF THE
COLD FRONT WILL SUPPORT LOW TOPPED CONVECTION IN THE GULF...AND
WITH A STRONG LOW LEVEL WIND FIELD...THERE IS A SLIGHT CHANCE FOR
THESE SHOWERS TO PUSH WELL INLAND OVERNIGHT. IT WILL TURN SHARPLY
COLDER AROUND SUNSET...BUT THE WEST FLOW OFF THE GULF WILL LIMIT
THE EFFECTS OF STRONG COLD ADVECTION DURING THE OVERNIGHT. LOW
TEMPS WILL DROP INTO THE UPPER 40S NORTH TO MID 50S SOUTH.
WEEKEND...STRONG LOW PRESSURE WILL MOVE SLOWLY UP THE EASTERN
SEABOARD. IN ITS WAKE WE WILL EXPERIENCE WINDY CONDITIONS ON SAT
THEN GRADUALLY DIMINISHING SUNDAY. A WIND ADVISORY MAY BE NEEDED
ON SAT.
THE AIR MASS WILL BE DRIER...AND QUITE COLD AGAIN...WITH CONSENSUS
GUIDANCE TEMPS IN THE MID 50S NORTH ON SAT TO THE LOWER 60S
SOUTH. OVERNIGHT LOWS SHOULD REACH THE MID 30S NORTH TO LOWER 40S
FAR SOUTH COAST...WITH WIND CHILL VALUES BEING LOWER. AFTER A
MORE CHILLY START TO SUNDAY...MAX TEMPS SHOULD BE A FEW DEGREES
LOWER THAN SAT.
MON-THU...SURFACE HIGH IS FORECAST OVER THE AREA MON MORNING SO
IT WILL CONTINUE CHILLY IN THE UPPER 30S TO LOWER 40S IN MOST
AREAS. HIGH PRESSURE WILL THEN PUSH OFFSHORE AND ALLOW FOR SLOW
AIR MASS MODIFICATION. THE NEXT COLD FRONT WILL BE MUCH WEAKER AND
SLOWER MOVING...SO THE RETURN OF MOISTURE SHOULD BE SLOWER AND
WILL HOLD OFF MENTION OF CHANCE POPS UNTIL WED-THU. TEMPS SHOULD
MODERATE TO A LITTLE ABOVE NORMAL EARLY IN THE PERIOD THEN STAY
CLOSE TO NORMAL SINCE THE FRONT WILL PROBABLY NOT SWEEP THROUGH.
&&
.AVIATION...THRU 22/12Z
SFC WINDS: THRU 21/14Z...VRBL AOB 3KTS. BTWN 21/14Z-21/17Z...BCMG
E/SE 7-11KTS. BTWN 21/23Z-22/02Z BCMG S/SE 3-6KTS. AFT 22/06Z...S/SE
LLWS DVLPG BLO FL020.
VSBYS/WX/CIGS: AOA FL120.
&&
.MARINE...
TODAY-TONIGHT...WEAK HI PRES RIDGE OVER THE SW ATLC/ERN GOMEX WILL
DRIFT EAST AND BREAK DOWN AS THE NEXT STORM SYSTEM TAKES SHAPE OVER
THE SRN PLAINS/DEEP SOUTH. LIGHT N/NE BREEZE OVR THE LCL ATLC THIS
MRNG BCMG A LIGHT TO GENTLE ERLY BREEZE BY MIDDAY...THEN A GENTLE TO
MODERATE SE BREEZE BY SUNSET AS THE STORM SYSTEM CROSS THE MS RIVER
VALLEY. WINDS WILL CONTINUE TO FRESHEN OVERNIGHT AS THE SYSTEM PULLS
A COLD FRONT INTO THE ERN GOMEX...BCMG A MODERATE TO FRESH S/SE
BREEZE IN THE PREDAWN HRS FRI MRNG. ONSET OF THE STRONGEST WINDS
WILL OCCUR TOO LATE FOR SEAS TO RESPOND BEFORE DAYBREAK...WILL KEEP
SEAS 2-3FT FROM SEBASTIAN INLET NWD...3-4FT TO THE SOUTH. SLGT CHC
OF SHRAS AFT MIDNIGHT...MAINLY OVER THE GULF STREAM.
FRI...A FRESH SOUTHEAST BREEZE WILL STEADILY VEER AND BECOME
SOUTHWEST BY LATE IN THE DAY AS A PRE FRONTAL SQUALL LINE RACES
EAST OF THE WATERS. SMALL CRAFT ADVISORY CONDITIONS EXPECTED.
FRI NIGHT-SAT...STRONG WEST WINDS 20-25 KNOTS NEAR SHORE AND 30
KNOTS WELL OFFSHORE CAN BE EXPECTED BEHIND THE FRONT. MAY NEED A
GALE WARNING FOR THE OFFSHORE WATERS.
SAT NIGHT-SUN...TIGHT PRESSURE GRADIENT WILL GRADUALLY START TO
EASE BUT HAZARDOUS BOATING CONDITIONS SHOULD CONTINUE INTO EARLY
SUNDAY.
MON...GREATLY IMPROVED BOATING CONDITIONS ARE FORECAST WITH HIGH
PRESSURE PROVIDING LIGHT WINDS...BUT IT WILL BE VERY CHILLY IN
THE MORNING.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 69 57 75 47 / 0 10 80 20
MCO 74 56 75 50 / 0 10 80 20
MLB 70 63 76 52 / 0 10 80 20
VRB 71 63 78 54 / 0 10 70 20
LEE 73 56 72 47 / 0 0 80 20
SFB 73 56 75 48 / 0 10 80 20
ORL 74 56 74 50 / 0 10 80 20
FPR 72 63 77 55 / 0 10 70 30
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
SHORT TERM...BRAGAW
LONG TERM....LASCODY
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
102 AM EST THU JAN 21 2016
.SYNOPSIS...
MOISTURE WILL INCREASE AHEAD OF LOW PRESSURE APPROACHING FROM THE
WEST. THE LOW WILL BE NEAR THE FORECAST AREA FRIDAY INTO FRIDAY
NIGHT AND ALONG THE NORTH CAROLINA AND VIRGINIA COASTS SATURDAY.
DRYING WILL OCCUR SUNDAY AS THE LOW MOVES FARTHER AWAY AND HIGH
PRESSURE APPROACHES FROM THE WEST.
&&
.NEAR TERM /THROUGH TODAY/...
HIGH PRESSURE WILL BE WEDGED INTO THE FORECAST AREA FROM THE NORTH
WITH A STRENGTHENING WARM FRONT SOUTH OF THE AREA TODAY. THE
MODELS INDICATE LITTLE ISENTROPIC LIFT IN THE NORTH SECTION OF THE
FORECAST AREA...BUT INCREASING LIFT IN THE SOUTH PART. THE NAM
AND GFS KEEP MOISTURE SHALLOW IN THE NORTH PART...BUT IT BECOMES
DEEPER IN THE SOUTH. THE HRRR AND ARW INDICATE SCATTERED AREAS OF
RAIN IN THE SOUTH HALF OF THE AREA. THE NAM AND GFS MOS INDICATE
POPS LESS THAN 20 PERCENT IN THE NORTH TO NEAR 60 PERCENT IN THE
SOUTH. OBSERVATION TRENDS PLUS THE NAM AND GFS KEEP SURFACE WET
BULB TEMPERATURES ABOVE FREEZING IN THE SOUTH PART WHERE WE EXPECT
PRECIPITATION. WE HAVE FORECASTED ALL LIQUID PRECIPITATION TODAY.
THE TEMPERATURE GUIDANCE APPEARS TOO WARM BECAUSE OF THE WEDGE
PATTERN TODAY.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
THREAT FOR WINTRY PRECIPITATION WITH SIGNIFICANT IMPACTS
INCREASING ACROSS THE NORTHERN MIDLANDS MAINLY FOR FREEZING RAIN
LATE THURSDAY NIGHT THROUGH FRIDAY. CONFIDENCE INCREASING...WINTER
STORM WATCH NOW IN EFFECT FOR LANCASTER AND CHESTERFIELD
COUNTIES...
SIGNIFICANT DEEPENING OF THE SURFACE LOW OVER THE MISSISSIPPI
VALLEY WILL OCCUR IN RESPONSE TO A NEGATIVE TILTING OF THE UPPER
TROUGH AS IT TRANSITIONS INTO A CLOSED LOW OVER MS/AL. ISENTROPIC
LIFT WILL STRENGTHEN OVER THE REGION THROUGH FRIDAY MORNING AS THE
WARM FRONT SLOWLY LIFTS NORTHWARD AND WILL CARRY CATEGORICAL POPS.
CONFLUENT 500MB FLOW OVER THE EASTERN OHIO VALLEY AND NORTHEAST
WILL RESULT IN A STRENGTHENING SURFACE RIDGE OVER THE MID ATLANTIC
AND COLD AIR DAMMING WILL DEVELOP ACROSS VA/NC INTO THE NORTHERN
PORTION OF THE FORECAST AREA THURSDAY NIGHT INTO FRIDAY. WETBULB
TEMPERATURES DROP ACROSS THE NORTHERN MIDLANDS FALLING BELOW
FREEZING BY EARLY FRIDAY MORNING. THIS WILL LIKELY RESULT IN A
PERIOD OF FREEZING RAIN IN THE NORTHERN MIDLANDS. THERE REMAIN
SOME DIFFERENCES AMONG THE GUIDANCE ON LOW LEVEL THERMAL PROFILES
WITH THE NAM/CANADIAN BEING COLDER THAN THE GFS WHICH LEADS TO
SOME UNCERTAINTY AS TO HOW FAR SOUTH THE FREEZING RAIN MAY BE.
HOWEVER...BASED ON LATEST GUIDANCE WINTER STORM WATCH POSTED FOR
NORTH MIDLANDS. THERE IS POTENTIAL FOR SIGNIFICANT ICING. WILL
CONTINUE TO MONITOR MODEL TRENDS...IF COLD AIR DAMMING IS
STRONGER...ICING MAY DEVELOP FURTHER SOUTH.
COMPLEX STORM SYSTEM EVOLUTION ON FRIDAY SHOWS THE INITIAL
SURFACE LOW LIFTING NORTHEASTWARD INTO EASTERN TENNESSEE WITH A
TRANSITION TO A COASTAL LOW DEVELOPING SOMEWHERE OVER EASTERN
SOUTH CAROLINA BY 00Z SATURDAY.
RELATIVELY STEADY TEMPERATURES THURSDAY NIGHT WITH CLOUDS AND
PRECIPITATION ALTHOUGH TEMPERATURES WILL LIKELY FALL ACROSS THE
NORTHERN MIDLANDS. EXPECT A STRONG GRADIENT IN TEMPERATURES ON
FRIDAY AS SURFACE LOW APPROACHES AND WARM ADVECTION OCCURS ACROSS
THE SOUTHERN PART OF THE AREA WHILE THE WEDGE HOLDS STRONG ACROSS
THE NORTH...THOUGH TEMPERATURES UP NORTH SHOULD ALSO RISE A BIT
FRIDAY AFTERNOON.
THIS LOOKS TO BE A POTENTIALLY SIGNIFICANT QPF EVENT WITH LIQUID
ACCUMULATIONS OF A 0.50-1.00 INCH WITH ACCUMULATING FREEZING RAIN
ACROSS PARTS OF THE NORTHERN MIDLANDS COUNTIES.
FRIDAY NIGHT AND SATURDAY...SURFACE LOW DEEPENS AND MOVES UP THE
COAST TO NEAR NORFOLK BY 12Z SATURDAY WHILE THE CLOSED UPPER LOW
SLOWLY MOVES OVER THE SOUTHERN APPALACHIANS BY SATURDAY MORNING. MID
LEVEL DRY SLOT FORECAST TO MOVE OVER THE FORECAST AREA FRIDAY NIGHT
INTO EARLY SATURDAY WHICH WILL RESULT IN MUCH LOWER POPS FRIDAY
NIGHT.
THE UPPER LOW WILL DRIFT EAST ACROSS THE CAROLINAS ON SATURDAY WITH
THE CORE OF THE COLD AIR ALOFT MOVING OVER THE FORECAST AREA WITH
500MB TEMPS AS COLD AS -26C TO -27C. THE AMOUNT OF MOISTURE
ASSOCIATED WITH THE UPPER LOW IS THE MAIN UNCERTAINTY AT THIS POINT
WITH THE 12Z NAM/CANADIAN SHOWING MUCH MORE SHALLOW MOISTURE
COMPARED TO THE GFS/ECMWF. 18Z NAM APPEARS TO SHOW DEEPER MOISTURE
INTO SNOW GROWTH ZONE. WILL GO WITH SNOW SHOWERS ACROSS MUCH OF
THE MIDLANDS AND CSRA SATURDAY. ACCUMULATION MORE LIKELY
NORTH...SOME LIGHT ACCUMULATION IN THE CENTRAL AND PIEDMONT.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
HIGH PRESSURE AND DRIER AIR WILL RETURN TO THE REGION FOR SUNDAY
AND MONDAY. THE NEXT COLD FRONT LOOKS TO CROSS THE REGION TUESDAY.
HAVE INDICATED A CHANCE OF SHOWERS MONDAY NIGHT INTO WEDNESDAY.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
VFR CEILINGS WERE OCCURRING AT TAF ISSUANCE TIME ASSOCIATED WITH
HIGH PRESSURE WEDGING INTO THE AREA FROM THE NORTH AND A WARM
FRONT JUST TO THE SOUTH. THE MODELS INDICATE INCREASING ISENTROPIC
LIFT AND MOISTURE MAINLY IN THE SOUTH PART AFFECTING AGS AND DNL
TODAY. THE DEEPER MOISTURE SHOULD SPREAD FARTHER NORTH AFTER 00Z. THE
NAM MOS AND SREF GUIDANCE WERE FASTER LOWERING CEILINGS COMPARED
TO THE GFS MOS. BASED ON OBSERVATION TRENDS WE LEANED TOWARD THE
NAM AT AGS AND DNL...AND USED AN AVERAGE OF THE GUIDANCE AT
CAE...CUB...AND OGB. THE MODELS WERE CONSISTENT KEEPING SURFACE
WET BULB TEMPERATURES ABOVE FREEZING AND WE HAVE INDICATED ALL
LIQUID PRECIPITATION DURING THE TAF PERIOD. USED THE GFS LAMP FOR
THE WIND FORECAST. EXPECT MAINLY EAST WINDS NEAR 5 KNOTS.
EXTENDED AVIATION OUTLOOK....PRECIPITATION AND WIDESPREAD IFR TO
MVFR CONDITIONS EXPECTED THROUGH SATURDAY. WINTRY PRECIPITATION IS
POSSIBLE SATURDAY. BREEZY CONDITIONS POSSIBLE SATURDAY AND
SATURDAY NIGHT.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...WINTER STORM WATCH FROM LATE TONIGHT THROUGH SATURDAY EVENING
FOR SCZ015-016.
&&
$$
SYNOPSIS...99
NEAR TERM...99
SHORT TERM...99
LONG TERM...99
AVIATION...99
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1034 PM MST WED JAN 20 2016
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 132 PM MST WED JAN 20 2016
WV IMAGERY AND RAP H5/H7 ANALYSIS SHOWS TWO SHORTWAVE TROUGHS
IMPACTING THE CENTRAL ROCKIES AND PLAINS. THE STRONGER CLOSED CENTER
JUST EAST OF OUR CWA OVER NORTH CENTRAL KANSAS AND HAS DEEPENED
THROUGH MIDDAY. THE SECOND IS ENTERING EASTERN COLORADO. BETWEEN
THESE FEATURES THERE IS A SHORTWAVE RIDGE AND REGION OF
DRY/SUBSIDENT AIR APPARENT ON WV IMAGERY. AT THE SURFACE...A SURFACE
TROUGH IS IN PLACE OVER EASTERN COLORADO AND WHERE SKIES HAVE
CLEARED TEMPS HAVE WARMED IN TO THE 40S/50S. OVER OUR CWA (EAST OF
TROUGH AXIS) EXTENSIVE CLOUD COVER HAS SIGNIFICANTLY LIMITED HEATING
AND SEVERAL UPDATES TO HIGH TEMPS WERE WARRANTED EARLIER TODAY.
THIS AFTERNOON-THURSDAY...FOCUS CONTINUES TO BE ON POTENTIAL FOR
SNOW ACROSS OUR CWA. RADAR IS SHOWING SIGNS OF INCREASE IN
REFLECTIVITY IN OUR EASTERN CWA AND HILL CITY HAS STARTED TO REPORT
LIGHT SNOW. THIS CORRELATES WITH OF STRONG VORTICITY NEAR CLOSED LOW
CENTER AND BETTER MID LEVEL MOISTURE IS BEGINNING TO FILL IT. TREND
WILL BE FOR THIS CENTER TO ROTATE NORTH AND EAST TONIGHT BEFORE
SLIDING WELL EAST OF OUR CWA. AN ELEVATED BAROCLINIC ZONE/REGION OF
WEAK FRONTOGENESIS WILL DEVELOP AS THESE SHORTWAVE INTERACT AND PLACE
THE NORTHERN HALF OF OUR CWA IN A FAVORABLE LOCATION FOR POSSIBLE
LIGHT SNOW DEVELOPMENT BY THURSDAY MORNING. THE LIMITING FACTOR WILL
BE MOISTURE ADVECTION AS BOTH SHORTWAVE WILL TEND TO CUT OFF GULF
MOISTURE AND MODELS HAVE GENERALLY LIMITED QPF OVER OUR CWA
ACCORDINGLY. IN THE MEAN TIME...THE DRY/SUBSIDENT REGION BETWEEN
FEATURES MAY LIMIT ANY SNOW DEVELOPMENT IN OUR SOUTH.
I FAVORED THE EASTERN/NORTHEAST PART OF OUR CWA TONIGHT AND
THURSDAY MORNING FOR HIGHEST POPS. SNOW TOTALS SHOULD GENERALLY
RANGE 0.5-1" THOUGH IF THE EASTERN SHORTWAVE WERE TO REMAIN CLOSER
TO OUR CWA WE MAY HAVE A ROW OF COUNTIES RECEIVE AROUND 2" WHEN ALL
IS SAID AND DONE. ALL SNOWFALL SHOULD QUICKLY DISSIPATE/TRANSITION
EASTWARD AS THE RESULTING COMBINED TROUGH SHIFTS EAST AND RIDGING
BUILDS INTO OUR CWA THURSDAY AFTERNOON.
MODELS CONTINUE TO SHOW STRONGER BL WINDS DEVELOPING ON BACK SIDE OF
UPPER LOW AS THE TWO SHORTWAVES MERGE AND POST FRONTAL PRESSURE
GRADIENT INCREASES. LOCATION OF STRONGEST WINDS ACTUALLY CORRELATES
WITH MOST LIKELY LOCATION OF DRY SLOT DEVELOPMENT AND ABOVE
FREEZING TEMPERATURES DURING THE DAY THURSDAY. MIXING MAY BE LIMITED
IN LOCATIONS WITH CLOUD COVER/SNOW AND BL WINDS ARE LESS TO THE
NORTHEAST WHERE SNOWFALL IS MOST LIKELY. SINCE STRONGEST WINDS ARE
UNLIKELY TO BE LOCATED WITH BETTER SNOW CHANCES AND ACCUMULATIONS
ARE LIGHT I DID NOT SEE THE NEED TO KEEP BLOWING SNOW IN THE
FORECAST. AT MOST WE MAY SEE A BRIEF PERIOD OF DRIFTING SNOW AS SNOW
WINDS DOWN BEFORE TEMPS INCREASE TO FREEZING (OR WARMER). ANY
DRIFTING WOULD BE MINOR CONSIDERING AMOUNTS WE ARE DEALING WITH AS
WELL AS PEAK GUSTS IN THE REGION OF BETTER LIGHT SNOW ACCUMULATIONS
20-25 MPH.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 132 PM MST WED JAN 20 2016
THERE ARE A COUPLE OF FORECAST CONCERNS IN THE LONG TERM PERIOD.
FIRST IS THE TEMPERATURE GRADIENT ACROSS THE FORECAST AREA
THROUGH THE END OF THE WEEK AND INTO THE WEEKEND AS COOLER AIR
MOVES EAST AND WARMER DOWNSLOPING CONDITIONS OCCUR OVER THE WEST.
SECOND IS THE POSSIBILITY AND TYPE OF PRECIPITATION LATE SUNDAY
THROUGH EARLY MONDAY MORNING AS THE WARM AND DRY PATTERN
TRANSITIONS BRIEFLY BACK TO A COOLER AND MORE ACTIVE PATTERN AS A
SERIES OF DISTURBANCES MOVES ACROSS THE REGION LATE IN THE WEEKEND
THROUGH EARLY NEXT WEEK.
THE UPPER RIDGE MOVES EAST OVER THE HIGH PLAINS ON THURSDAY NIGHT
THROUGH FRIDAY NIGHT AND CONTINUES OVER THE EASTERN PLAINS STATES
ON SATURDAY. THE COOLER AREA OF HIGH PRESSURE AT THE SURFACE MOVES
INTO THE PLAINS STATES BY FRIDAY...WITH A LEE TROUGH DEEPENING
ALONG THE FRONT RANGE IN RESPONSE TO THE FLATTENING UPPER FLOW AS
AS SEVERAL SHORT WAVE TROUGHS MOVE THROUGH THE UPPER FLOW
SATURDAY NIGHT AHEAD OF THE NEXT MAIN UPPER TROUGH AXIS. THIS WILL
KEEP THE COOLER AIR OVER THE FAR EASTERN SECTIONS OF THE FORECAST
AREA AS THE WESTERN SECTIONS WARM UP. THE THURSDAY NIGHT THROUGH
SATURDAY NIGHT TIME PERIOD WILL STAY DRY AS A RESULT. HOWEVER...THE
TEMPERATURE GRADIENT ACROSS MY FORECAST AREA IS USUALLY MORE
DRAMATIC THAN DEPICTED BY ANY MODEL SOLUTIONS AND HAVE THEREFORE
TRIED TO GO TOWARDS THE WARM END OF GUIDANCE OVER THE WEST AND
TOWARDS THE COOL END OF GUIDANCE OVER THE EAST TO MAKE THE
GRADIENT MORE DRAMATIC. ANY RELUCTANCE OF LOW CLOUD COVER TO
DISSIPATE OVER THE EASTERN SECTIONS...AS HAS BEEN THE CASE OVER
RECENT DAYS...WILL ALSO ACT TO INCREASE THE TEMPERATURE GRADIENT.
A SURFACE LOW CONSOLIDATES OVER THE NORTHERN PANHANDLE REGION ON
SUNDAY...LIFTING INTO MISSOURI BY MONDAY MORNING ALONG THE
FRONTAL BOUNDARY EXTENDING FROM THE GREAT LAKES INTO THE SOUTHERN
PLAINS AS THE MAIN UPPER TROUGH AXIS MOVES EAST OF THE ROCKIES BY
SUNDAY AFTERNOON. A DEEPER AND BROADER UPPER TROUGH IS EVENTUALLY
CARVED OUT OVER MUCH OF THE UNITED STATES EAST OF THE ROCKIES BY
MONDAY NIGHT AS ANOTHER RIDGE MOVES INTO PLACE OVER THE WEST
COAST. THIS WILL OPEN THE DOOR TO COLDER AIR DIVING SOUTH INTO THE
PLAINS STATES ON MONDAY. WITH THE TRACK OF THE SURFACE LOW
REMAINING WELL SOUTH OF THE FORECAST AREA AND LITTLE MOISTURE TO
WORK WITH...EXPECT ONLY A SLIGHT CHANCE OF LIGHT RAIN OR SNOW
LATE SUNDAY TRANSITIONING TO ALL SNOW SUNDAY EVENING...WITH
MINIMAL ACCUMULATIONS POSSIBLE MAINLY ACROSS SOUTHERN NEBRASKA AND
EASTERN COLORADO.
THE UPPER WEST COAST RIDGE FLATTENS AND MOVES EAST OVER THE
MOUNTAINOUS WEST BETWEEN SUNDAY AND WEDNESDAY WITH ANOTHER LEE
TROUGH DEEPENING ALONG THE FRONT RANGE. WESTERLY NEAR SURFACE
FLOW WILL PRODUCE DRYING CONDITIONS AND WARMING TEMPERATURES
AGAIN OVER THE FORECAST AREA ON TUESDAY AND WEDNESDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1026 PM MST WED JAN 20 2016
LIFR CONDITIONS WILL CONTINUE AT KMCK OVERNIGHT WHILE CONDITIONS
AT KGLD LOWER TO IFR. LIGHT SNOW AND MVFR CONDITIONS SHOULD
DEVELOP AROUND SUNRISE AT BOTH SITES AS THE NEXT SHORTWAVE
IMPACTS THE AREA. KGLD WILL HAVE LOWER CHANCES OF LIGHT SNOW THAN
KMCK. VFR CONDITIONS WILL RETURN TO BOTH SITES BY MID TO LATE
AFTERNOON AS THE DISTURBANCE EXITS. VFR CONDITIONS SHOULD PERSIST
THROUGH THURSDAY EVENING.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...LOCKHART
AVIATION...FS
Area Forecast Discussion
National Weather Service SPRINGFIELD MO
318 AM CST THU JAN 21 2016
.SHORT TERM...(Today and Tonight)
Issued at 0233 AM CST THU JAN 21 2016
A light wintry mix is again affecting the area as lift ahead of a
subtle shortwave over se KS/ne OK is producing a mix of sleet/snow
showers into our western cwfa as of 230 am. MODOT road reports
indicate some covered/partially covered roads where the precip has
occurred. HRRR and other high resolution models show this precip
moving northeast into much of the rest of the cwfa over the next
few hours, exiting our northern counties by 9-10 am or so. A
little bit of MUCAPE supports some heavier "showery" pockets of
precip. Model soundings show the precip type to be mostly snow
once any dry air saturates/wet bulbs (evaporative cooling), but
some sleet will occur with convective/showery pockets.
Cloud ice quickly diminishes in the wake of the band of precip.
Could see a bit of freezing drizzle today with some weak low level
isentropic upglide persisting over the northern and eastern cwfa.
Will watch trends on that closely today. Will have to take a look
at expanding the advisory farther east as conditions warrant. Not
planning on any changes right now.
Another issue will be the far south central MO/se cwfa as another
stronger shortwave now moving into nw TX moves east into the
lower MS River late tonight. The northern edge of the precip/snow
with this system will affect the MO/AR border region late tonight.
Fcst database has about 1-2 inches of snow for southern Oregon
County. May have to look at that area for an advisory, but it`s
borderline both geographically and by "criteria". There`s time for
the dayshift to take a look.
.LONG TERM...(Friday through Wednesday)
Issued at 0233 AM CST THU JAN 21 2016
The rest of the forecast looks fairly quiet/tame for our area. A
cold Friday will give way to warmer temperatures this weekend as
an upper level ridge builds over the area in the wake of the
developing eastern CONUS storm. There is decent guidance agreement
with another system by late Sunday night into Monday with some
light precip possible (rain...maybe a bit of snow). Colder
temperatures spread back in after the system exits.
&&
.AVIATION...(For the 06Z TAFS through 06Z Thursday Night)
Issued at 1159 PM CST WED JAN 20 2016
Long duration IFR continues across the region. A band of mixed
precip will move across the region during the overnight hours.
Accumulations will be light, but enough to cause trouble given
temperatures in the upper 20s. Ceilings will gradually lower to
LIFR during the overnight hours, with gradual improvement during
the day Thursday. Visibility will be lowest with any drizzle/mist.
&&
.SGF Watches/Warnings/Advisories...
MO...Winter Weather Advisory until noon CST today for MOZ055-066>069-
077>082-088>097-101>105.
KS...Winter Weather Advisory until noon CST today for KSZ073-097-101.
&&
$$
SHORT TERM...DSA
LONG TERM...DSA
AVIATION...Gagan
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1136 PM CST WED JAN 20 2016
.UPDATE:
Issued at 859 PM CST Wed Jan 20 2016
Mid-high level cloudiness will continue to spread eastward
through our forecast area ahead of a strong shortwave moving
slowly eastward through KS. There may also be some stratus clouds
developing or retrograding from IL into parts of the area. The
radar was depicting some light precipitation in eastern KS ahead
of the shortwave. Looking at the latest HRRR and NAM model runs it
appears that this precipitation will remain west of our forecast
area tonight. With the cloud cover and lowering cloud ceilings
expected the temperatures later tonight should be nearly steady or
even rise slightly.
GKS
&&
.SHORT TERM: (Through Late Tonight)
Issued at 330 PM CST Wed Jan 20 2016
Morning stratus has developed several holes in it during the course
of the day and now only occupies areas in southern IL and northeast
MO. Temps are in the upper 20s and lower 30s where the sun has
broken out of the clouds, while still in the lower to mid 20s
elsewhere. Another storm system has taken shape over western and
central KS with an area of snow, while a much more significant
system is moving thru UT and western CO at this time.
The system over KS is expected to move slowly east tonight and
weaken with time, only making it to the eastern part of the state by
12z/Thu. Any pcpn associated with this system should remain to the
west of our region tonight. Of more significant note and challenge
will be sky cover, its effects on temps, and potential for any fog.
Sky cover should come from two main sources tonight: first from mid
and hi clouds that will overspread our region later this evening
from the KS system, and also from the low stratus that survives
(mainly in southern IL) that will take advantage of veering cloud
level winds from north to southeast to both advect westward into the
heart of our region and expand in coverage as it does so.
Ultimately, this will cloud up all areas again, but not before many
areas will have the opportunity to have several hours of mostly
clear skies with light easterly winds this evening with fresh snow
cover. Have tried to compensate for this contingency in the min
temp forecast, allowing for some areas in IL especially to drop into
the single digits, and this will probably also allow for some fog
development. As clouds increase later tonight, should see temps
either steady out or even rise a few degrees. Biggest adjustments
to MOS min temps are to the north and northeast of STL.
TES
.LONG TERM: (Thursday through Next Wednesday)
Issued at 330 PM CST Wed Jan 20 2016
Focus continues to be system on Thurs into Fri.
Latest mdl guidance has continued a more sly track. Mdls do continue
to track a leading s/w lifting newd into the region late tonight
into Thurs. Can not completely rule out light precip across portions
of central MO, but based on forecast soundings, any precip will be
light and sct. Of some concern is that while the NAM is the only mdl
to suggest precip across this area, soundings also suggest that the
available moisture may not be deep enuf for SN and FZDZ may be a
threat.
Otherwise, PoPs have been removed thru the weekend. Will need to
continue to monitor the more nrn trof Thurs night into Fri as it
drops swd into the area. Mdls suggest that any available moisture
will precip out before it reaches the CWA. Regardless, will need to
continue to monitor.
Focus then turns to a system on Mon into Tues with a more amplified
trof digging into the region. Mdls disagree regarding how this
system will evolve and have therefore kept PoPs on the low end. Have
also kept a RA vs. SN going for now. Will begin to fine tune p-types
as the system approaches and mdls come into better agreement.
Tilly
&&
.AVIATION: (For the 06z TAFs through 06z Thursday Night)
Issued at 1127 PM CST Wed Jan 20 2016
The expected trends of the stratus have not materialized this
evening. Instead the low level flow across IL into the OH Valley
has maintained a northerly component which has kept the stratus
pushing south. This has raised serious doubts whether it can
advect back into the region overnight into Thursday morning after
the flow finally veers to southeasterly. Most of the guidance
suggests NOT, so I am being optomistic keeping flight conditions
predominately VFR dominated by mid-high clouds, with some light
fog potential at KUIN. Still also a remote chance for some spotty
very light snow across parts of central MO but the probability is
very low and most likely not much more than flurries.
Specifics for KSTL:
The expected trends of the stratus have not materialized this
evening and I have serious doubts whether we will see any.Most of
the guidance suggests NOT, so I am being optomistic keeping
flight conditions predominately VFR dominated by mid-high clouds.
Glass
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1119 PM CST WED JAN 20 2016
.UPDATE...
ISSUED AT 653 PM CST WED JAN 20 2016
BASED ON CURRENT TRENDS AND REPORTS AND THE LATEST HIGH-RES
GUIDANCE HAVE INCREASED SNOW AMOUNTS FOR PORTIONS OF THE
AREA...MAINLY FRANKLIN COUNTY NEBRASKA AND PHILLIPS AND ROOKS
COUNTIES IN KANSAS. EXPECT BETWEEN 2 AND 4 INCHES IN THOSE
LOCATIONS AND HAVE EXPANDED THE WINTER WEATHER ADVISORY TO INCLUDE
THESE COUNTIES. WILL CONTINUE TO UPDATE AS NECESSARY.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 356 PM CST WED JAN 20 2016
BIGGEST FORECAST ISSUE WILL BE SNOW AMOUNTS FOR TONIGHT.
SNOW HAS BEGUN A BIT EARLIER THAN ANTICIPATED IN OUR SOUTH IN
ADVANCE OF THE LONG-AWAITED APPROACHING WAVE WITHIN PROGRESSIVE
FLOW. BACKED UP THE START TIME OF THE ADVISORY FOR OUR KANSAS
COUNTIES TO INCLUDE THIS AFTERNOON. ALSO INCREASED SNOW AMOUNTS A
BIT IN OUR SOUTH...WHICH REQUIRED THE ADDITION OF A FEW COUNTIES ON
THE WESTERN EDGE OF THE WINTER WEATHER ADVISORY...TO INCLUDE
WEBSTER...SMITH...AND OSBORNE COUNTIES. EXPECTING A RATHER TYPICAL
13:1 RATIO FOR LIQUID TO SNOW.
FORECAST IS LARGELY ON TRACK FROM THE PREVIOUS FORECAST TONIGHT WITH
MINOR CHANGES MADE IN GENERAL. SNOWFALL MAY NOT FOLLOW A SMOOTH
TRANSITION FROM HEAVIER TO LIGHTER AMOUNTS FROM SOUTH TO NORTH...AS
WE COULD GET A FEW CONVECTIVE BANDS TO MOVE THROUGH...AS INDICATED
BY SHORT TERM MODELS SUCH AS HRRR AND RAP.
ANOTHER ISSUE MAY COME LATE THURSDAY AFTERNOON WHEN WE COULD LOSE
SATURATION IN THE DENDRITIC GROWTH ZONE BEFORE ALL OF THE LIGHT
LINGERING PRECIPITATION EXITS. IF THIS OCCURS...THEN WE COULD GET
SOME FREEZING DRIZZLE DEVELOP LATE AFTERNOON THURSDAY.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 356 PM CST WED JAN 20 2016
HAZARDOUS WX POTENTIAL: NOTHING SIGNIFICANT FORESEEN AT THIS TIME.
ALOFT: SOME TEMPORARY PROGRESSION OF THE LONGWAVES WILL OCCUR AS THE
PERSISTENT E PAC TROF MOVES ONSHORE SAT AND INTO THE CNTRL USA SUN-
MON. THIS TROF WILL SHIFT INTO THE ERN USA BEYOND MON. THEN IT`S
BACK TO THE PATTERN DOMINATING THE PAST 2 WEEKS...WITH THE E PAC
TROF/WRN N AMERICA RIDGE REDEVELOPING.
SURFACE: CANADIAN HIGH PRES WILL CREST OVER THE FCST AREA THU NIGHT
INTO FRI. SAT THE FCST AREA WILL BE IN THE WARM SECTOR OF A CLIPPER
TRACKING ACROSS SRN CANADA. LEE CYCLOGENESIS WILL ENSUE SAT NIGHT
WITH THE APPROACH OF THE UPR TROF. A PAC COLD FRONT WILL SLIP THRU
SUN AS THIS LOW CONTS TO ORGANIZE OVER OK/KS. WPC HAS THIS LOW OVER
CNTRL MO AT 12Z/MON WHICH IS CLOSE TO THE 06Z/12Z GFS AND THE
00Z/12Z GEM. INTERESTINGLY...THE 12Z GFS ENSEMBLE MEAN IS ON THE
SLOW END OF THE GUIDANCE SPREAD (OVER ERN KS/OK) WHILE THE 00Z/12Z
EC AND THE 00Z ENSEMBLE MEAN ARE ON THE FASTER END OVER IA.
HIGH PRES OVERTAKES THE REGION MON AND SINKS INTO THE SRN PLAINS TUE-
WED. DOWNSLOPE-WARMED AIR SHOULD FLOOD THE PLAINS AS A COUPLE
CLIPPERS TRACK N OF THE FCST AREA.
SOME DAILY DETAILS...
THU NIGHT: A LITTLE LIGHT SNOW OR FRZG DRZL COULD LINGER INTO THE
EVENING HRS MAINLY HWY 81. CONFIDENCE IS LOW. OTHERWISE CLOUDY. KEPT
LOW TEMPS A LITTLE ABOVE NORMAL.
FRI: LOTS OF UNCERTAINTY ON DEPARTURE OF THE LOW CLOUDS...BUT THE
THERMAL TROF SHIFTING E IS A GOOD SIGN. HIGH TEMPS ARE LOW
CONFIDENCE. THE SNOW THAT FALLS TONIGHT WILL BE A PLAYER.
SAT: INCREASING/DESCENDING MULTI-LAYERED CLOUDS...ESPECIALLY IN THE
AFTERNOON. IT`S LOOKING VERY MILD...BUT AGAIN SNOW COVER A
MITIGATING FACTOR.
SUN: THE FCST IS CURRENTLY DRY...BUT IT`S POSSIBLE SOME LIGHT PRECIP
COULD BREAK OUT IN THE AFTERNOON. NOT EXACTLY SURE ON PRECIP TYPE AS
WETBULB COOLING COULD BE AN ISSUE IN THE INITIALLY DRY AIR BELOW 10K
FT.
THE LAST 2 RUNS OF THE OP MODELS ARE ALL OVER THE PLACE WITH VERY
LIGHT QPF AND AMTS SUN NIGHT. THE 12Z GFS ENSEMBLE DOES HAVE A 30%
PROBABILITY FOR .10" IN 24 HRS OVER S-CNTRL NEB. THE 12Z EC ENSEMBLE
IS SIMILAR. SO THERE COULD BE A TOUCH OF LIGHT WINTRY PRECIP.
MON: A LITTLE LIGHT SNOW COULD LINGER INTO THE MORNING. COLD SECTOR
WITH THERMAL TROF PASSING THRU. COLDER AND PROBABLY M/CLOUDY.
TUE-WED: DRY AND QUIET WITH TEMPS MODERATING.
&&
.AVIATION...(FOR THE 06Z KGRI/KEAR TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1114 PM CST WED JAN 20 2016
SNOW WILL BE THE MAIN CONCERN EARLY IN THE PERIOD. THIS WILL BRING
THE LOWER VISIBILITIES AND CEILINGS...BUT EVEN AS THE SNOW LETS UP
TOWARD MORNING THE CEILINGS WILL CONTINUE TO BE IFR OR LIFR FOR A
TIME. LOW CLOUDS WILL CONTINUE THROUGH THE ENTIRE PERIOD.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...WINTER WEATHER ADVISORY UNTIL NOON CST THURSDAY FOR NEZ084>087.
KS...WINTER WEATHER ADVISORY UNTIL NOON CST THURSDAY FOR KSZ005>007-
017>019.
&&
$$
UPDATE...BILLINGS WRIGHT
SHORT TERM...HEINLEIN
LONG TERM...HALBLAUB
AVIATION...JCB
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1233 AM CST THU JAN 21 2016
.UPDATE...
ISSUED AT 1232 AM CST THU JAN 21 2016
LOW STRATUS CLOUDS WITH WIDESPREAD LIGHT FOG AND PATCHY DENSE FOG
WILL CONTINUE THROUGH THE MORNING HOURS. SCATTERED LIGHT RADAR
RETURNS IN THE SOUTHWEST MAY BE MORE INDICATIVE OF SOME MID LEVEL
CLOUDS RATHER THAN ANY LIGHT SNOW...AS SURFACE OBSERVATIONS IN THAT
AREA WERE NOT REPORTING ANY PRECIPITATION. THE LATEST ITERATIONS OF
THE SHORT TERM MODELS ARE INDICATING THAT THE CHANCE OF LIGHT SNOW
FOR OUR AREA WILL BEGIN JUST BEFORE DAYBREAK IN NORTHWESTERN NORTH
DAKOTA AND SPREAD SOUTHEASTWARD INTO CENTRAL NORTH DAKOTA...EXITING
THE FAR SOUTH CENTRAL DURING THE AFTERNOON. ONLY LIGHT AMOUNTS
POSSIBLE. NO MAJOR CHANGES FROM THE PREVIOUS UPDATE.
UPDATE ISSUED AT 936 PM CST WED JAN 20 2016
WE HAVE UPDATED TO EXPAND THE FOG MENTION INTO SOUTHWEST ND BASED
ON THE 1/4SM VISIBILITY REPORTED BY THE DICKINSON ASOS AT 03 UTC.
THE FOG IS STILL NOT PARTICULARLY WIDESPREAD...WITH THE OBSERVED
VISIBILITIES AT GLEN ULLIN AND TIOGA BOTH HAVING IMPROVED IN THE
LAST 30 MINUTES AFTER BEING UNDER 1SM EARLIER. THE BISMARCK RAOB
FROM 00 UTC AND MODIFIED RICHARDSON NUMBER OUTPUT IN BUFKIT BOTH
SUGGEST THE BOUNDARY LAYER MAY BE A BIT TOO DECOUPLED/TURBULENT
FOR LONG-LIVED AND WIDESPREAD FOG DEVELOPMENT WITHOUT A SURFACE-
BASED INVERSION. THAT MAY ALSO BE WHY HRRR RUNS THIS EVENING HAVE
CORRECTLY ASSIMILATED OBSERVED LOW VISIBILITIES FOR THEIR 00-HOUR
INITIALIZATIONS AND QUICKLY REMOVED IT BY THEIR HOUR-02 FORECAST.
GIVEN THIS SCENARIO...WE STILL EXPECT FOG MAY LIFT OVER WESTERN ND
AFTER MIDNIGHT...AND LINGER IN A RATHER MODEST FASHION CENTRAL.
OTHERWISE...ONCE AGAIN THIS UPDATE ONLY YIELDED MINOR ADJUSTMENTS
TO THE REMAINDER OF THE FORECAST...WITH LOW-END SNOW CHANCES OVER
WESTERN ND OVERNIGHT AS A WEAK SHORTWAVE TROUGH APPROACHES.
UPDATE ISSUED AT 619 PM CST WED JAN 20 2016
FOG HAS DEVELOPED AND REDUCED VISIBILITY TO LESS THAN 1SM IN THE
TIOGA AND STANLEY AREAS SINCE 23 UTC...SO WE SPREAD THE MENTION OF
FOG INTO NORTHWEST ND THIS EVENING. WE WILL MONITOR TRENDS IN CASE
VISIBILITY REDUCTIONS BECOME LOW ENOUGH FOR A LONG ENOUGH TIME TO
REQUIRE A DENSE FOG ADVISORY...BUT RECENT HRRR SIMULATIONS SUGGEST
FOG WILL NOT BE AS PREVALENT AS LAST NIGHT AS MID- AND HIGH-LEVEL
CLOUD COVER INCREASES. OTHER THAN ADJUSTING THE FOG MENTION...FEW
CHANGES WERE MADE WITH THIS UPDATE.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 247 PM CST WED JAN 20 2016
MAIN CONCERNS THIS PERIOD WILL BE FOG THIS EVENING AND OVERNIGHT
THEN LIGHT SNOW TONIGHT AND THURSDAY.
FOG HAS BEEN SLOW TO LIFT ACROSS THE NORTHERN JAMES RIVER VALLEY
WITH VISIBILITIES AROUND ONE HALF MILE MUCH OF THE AFTERNOON. AS
MID/HIGH CLOUDS OVERSPREAD THE REGION EXPECT THE FOG TO GRADUALLY
IMPROVE INTO THE EVENING HOURS. BUFKIT SOUNDINGS SHOW LOW LEVEL
SATURATION OVER THE JAMESTOWN-BISMARCK-MINOT AREA SO HAVE KEPT FOG
IN THROUGH TONIGHT THIS AREA.
A BUILDING H500 RIDGE OVER THE WEST COAST THROUGH 36 HOURS WILL
NUDGE A WEAK SHORTWAVE DOWN THE EAST SIDE OF IN INTO THE NORTHERN
PLAINS AND WEAKLY IMPACT NORTH DAKOTA TONIGHT AND THURSDAY. TODAYS
DETERMINISTIC MODEL RUNS HAVE BEEN LESS ROBUST IN GENERATING
PRECIPITATION THAN PREVIOUS ONES. GENERALLY LOWERED POPS INTO THE
CHANCE CATEGORY TONIGHT AND THURSDAY. SNOW FALL TOTALS REMAIN BELOW
ONE INCH.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 247 PM CST WED JAN 20 2016
MAIN MESSAGE WILL BE THE BRIEF WARMING TREND SLATED FOR FRIDAY AND
SATURDAY. AN UPPER LEVEL RIDGE WILL SHIFT FROM THE NORTHERN ROCKIES
INTO THE NORTHERN HIGH PLAINS FRIDAY. THE RIDGE SHIFTS EAST SATURDAY
AS HEIGHTS FLATTEN IN RESPONSE TO A SHORTWAVE AND SURFACE LOW MOVING
ACROSS SOUTHERN CANADA. THE NAEFS (NORTH AMERICAN ENSEMBLE FORECAST
SYSTEM) SITUATION TABLE SHOWS H85-H7 TEMPS IN THE 90TH TO 97TH
PERCENTILE FRIDAY THROUGH SATURDAY. MAX 850MB TEMPS OF +6C TO +8C
WILL SLIDE ACROSS WESTERN AND CENTRAL NORTH DAKOTA DURING THIS TIME
PERIOD. HOWEVER...THE NAM/GFS BUFKIT SOUNDINGS ADVERTISE QUITE A BIT
OF LOW LEVEL MOISTURE TRAPPED UNDERNEATH THE WARMER TEMPERATURES
ALOFT/INVERSION FRIDAY...BUT NOT AS MUCH BY SATURDAY AFTERNOON.
THUS OTHER THAN FAR WESTERN NORTH DAKOTA FRIDAY...WE PROBABLY WILL
NOT BE ABLE TO REALIZE THE MAXIMUM WARMTH ALOFT/MIXING TO THE
SURFACE UNTIL SATURDAY...AS MORE SUNSHINE AND THE PASSAGE OF A
SURFACE TROUGH/PSEUDO COLD FRONT OCCURS. HIGHS FRIDAY WILL RANGE
FROM THE 20S CENTRAL TO MID AND UPPER 30S WEST. BY SATURDAY HIGHS OF
33F TO 43F ARE EXPECTED ACROSS WESTERN AND CENTRAL NORTH DAKOTA.
THE MAIN COLD FRONT AND MAXIMUM COLD AIR ADVECTION SLIDES THROUGH
SATURDAY NIGHT INTO SUNDAY. THIS WILL OCCUR IN CONJUNCTION WITH A
SHORTWAVE COMING IN FROM THE WEST RESULTING IN A CHANCE OF SNOW
SUNDAY AND POSSIBLY INTO MONDAY. THE GFS AND ECMWF ARE NOT IN
AGREEMENT WITH THE TIMING OF SNOW. THE GFS ADVERTISES A DRY SUNDAY
AND SOME SNOW MONDAY...WHILE THE ECMWF SHOWS CHANCES OF SNOW SUNDAY
BUT VERY LITTLE MONDAY. IT WOULD APPEAR THE SUPERBLEND IS IN FAVOR
OF THE ECMWF WITH SUNDAY/SUNDAY NIGHT BEING THE FAVORED TIME FOR
SNOW. COLDER TEMPERATURES WILL ENSUE SUNDAY THROUGH WEDNESDAY WITH
HIGHS MOSTLY IN THE 20S. THE WEATHER COULD A BIT MORE ACTIVE MIDWEEK
AND ONWARD AS A SERIES OF CLIPPERS ARE POSSIBLE...PER GFS AND
ECMWF.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1232 AM CST THU JAN 21 2016
WIDESPREAD IFR TO LIFR CONDITIONS IN LOW CLOUDS AND SOME FOG WILL
CONTINUE ACROSS WESTERN AND CENTRAL ND OVERNIGHT AND INTO THE DAY
THURSDAY. LIGHT SNOW SHOWERS ARE POSSIBLE ON THURSDAY WHEN A WEAK
DISTURBANCE CROSSES THE AREA. IN THE WAKE OF THAT SYSTEM...FLIGHT
CONDITIONS MAY IMPROVE AS CEILINGS COULD BEGIN TO LIFT AT LEAST A
BIT AFTER ABOUT 21 UTC...BUT CONFIDENCE IN THAT REMAINS LOW.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JV
SHORT TERM...WAA
LONG TERM...KS
AVIATION...CJS
AREA FORECAST DISCUSSION
NWS Tulsa OK
1126 PM CST WED JAN 20 2016
...UPDATE...
.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG.
MVFR/IFR conditions expected to persist through the night and
into much of the day on Thursday. Band of mixed precipitation
along with isolated thunderstorms will impact the northwest
AR sites toward 06z and should move east of the area around
09-10z. Areas of light drizzle or freezing drizzle may persist
through the night.
&&
.PREV DISCUSSION... /ISSUED 909 PM CST WED JAN 20 2016/
DISCUSSION...
Precipitation is starting to develop to the west of the Tulsa
CWA this evening as a mid-level shortwave works across Oklahoma.
With temperatures slowly creeping upwards across northern portions
of the forecast area through the evening...the forecast has become
somewhat trickier. The HRRR is doing a good job of developing precipitation
across the area and expect the precip shield to continue to blossom through
the night. Precip type is the tricky part. After looking at the latest
NAM forecast soundings, light snow and freezing drizzle seem like the best
bet across far north Oklahoma and into northwest Arkansas tonight. However,
some heavier freezing rain/rain may also develop across these areas. With
temperatures so close to freezing and still some uncertainty in the forecast
will not issue and advisory at this time. However, we will continue to closely
monitor and refine the forecast. Further to the south, mainly rain is expected.
however, a few pockets below the freezing mark will see freezing rain and possibly
sleet. There is also enough elevated instability for a few thunderstorms across
southeast Oklahoma tonight.
TSA Watches/Warnings/Advisories...
OK...NONE.
AR...NONE.
$$
&&
.TSA Watches/Warnings/Advisories...
OK...Winter Weather Advisory until 6 AM CST Thursday for OKZ058-063.
AR...Winter Weather Advisory until 6 AM CST Thursday for ARZ001-002-
010-011.
&&
$$
AVIATION...18
AREA FORECAST DISCUSSION
NWS PORTLAND OR
906 PM PST WED JAN 20 2016
.SYNOPSIS...A WARM FRONT OVER THE NORTHERN OREGON COASTAL WATERS THIS
EVENING WILL PUSH NORTH INTO WESTERN WASHINGTON TONIGHT. A MOIST
FRONTAL BOUNDARY IS EXPECTED TO BE OVER WESTERN WASHINGTON AND
EXTREME NORTHWEST OREGON EARLY THURSDAY THEN MOVE VERY SLOWLY EAST
DURING THE DAY. THE FRONTAL BOUNDARY EVENTUALLY SPLITS AS IT
CONTINUES TO MOVE INLAND THURSDAY NIGHT AND FRIDAY MORNING. ANOTHER
LOW WILL APPROACH FROM THE SOUTHWEST FRIDAY NIGHT AND SATURDAY. SNOW
LEVELS WILL LOWER TO NEAR THE CASCADE PASSES OVER THE WEEKEND. THE
PROGRESSIVE WEATHER PATTERN WILL CONTINUE PERIODS OF RAIN AND CASCADE
SNOW INTO NEXT WEEK.
&&
.SHORT TERM...WATER VAPOR IMAGERY THIS EVENING SHOWS A BAROCLINIC
BOUNDARY EXTENDING FROM NEAR VANCOUVER ISLAND SW TO 35N 133W. A
COUPLE OF WAVES CAN BE SEEN RIDING ALONG THE FRONTAL BOUNDARY. THE
PARENT LOW WAS AROUND 50N 145W. THERE IS A WARM FRONT...BUT IT IS
SOMEWHAT HARD TO DISCERN IN THE WATER VAPOR IMAGERY. 04Z OBS SHOW
SOUTH WIND UP TO KEUG. KRTX DUAL-POL DOPPLER RADAR INDICATING THE
WIDESPREAD LIGHT PRECIP OVER THE FAR N OREGON COAST INTO SW WA. HAD
ALREADY BOOSTED POPS EARLIER THIS EVENING TO ACCOUNT FOR LIGHT PRECIP
IN THE CENTRAL AND SOUTH INTERIOR VALLEYS.
OFFSHORE SURFACE GRADIENTS CONTINUE TO STRENGTHEN THIS EVENING. AT
04Z THE KTTD-KDLS GRADIENT WAS -4.9 MB. THIS WILL PEAK AROUND -6 TO
-7 MB THU. THE KAST PROFILER INDICATES A SNOW LEVEL CLOSE TO 7500
FEET. HOWEVER...THE OFFSHORE LOW-LEVEL FLOW WILL RESULT IN MUCH LOWER
SNOW LEVELS IN THE HIGHER VALLEYS OF EASTERN SKAMANIA COUNTY IN
WASHINGTON...AND ALSO THE EAST SLOPES AROUND MT. HOOD. NAM SOUNDING
FOR A VALLEY LOCATION AROUND 2500 FT WEST OF MT. ADAMS SHOWS A SMALL
THREAT OF LIGHT FREEZING RAIN TONIGHT...BUT BELIEVE THE AIR MASS WILL
WARM ENOUGH BY THU TO END THAT THREAT. THE 00Z GFS SHOWS HIGHER QPF
OVER THE SW WA LOWLANDS AND EXTREME N OREGON COAST 06Z THU TO 00Z
FRI. BOOSTED QPF IN THOSE AREAS...BUT DID NOT GO QUITE AS HIGH AS THE
GFS WOULD SUGGEST.
THE ACTUAL BAROCLINIC BOUNDARY STARTS TO MAKE SOME HEADWAY INLAND THU
AFTERNOON...BUT THEN APPEARS TO SPLIT AND WEAKEN THU NIGHT AND FRI
MORNING AS IT CONTINUES TO PUSH INLAND. NAM...GFS AND ECMWF ALL HAVE
A DEVELOPING LOW NEAR 38N 135W 12Z FRI...WHICH ENDS UP COMING ASHORE
SOMEWHERE OVER SW OREGON LATE FRI NIGHT. THIS LOW WILL SEND A WARM
FRONT ACROSS NW OREGON AND SW WASHINGTON FRIDAY NIGHT AND SATURDAY.
WEISHAAR
.LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY. LITTLE CHANGE
TO THE FORECAST AS MODELS REMAIN IN REASONABLY GOOD AGREEMENT
THROUGH THE PERIOD. UPPER TROUGH SLIDES EAST OF THE CASCADES BY LATE
SATURDAY NIGHT WITH RESIDUAL SHOWERS TAPERING OFF AS SHORTWAVE
RIDGING BUILDS OVER THE REGION IN BETWEEN SYSTEMS. MODELS SUGGEST
THE NEXT DISTURBANCE MAY SPLIT OFFSHORE AS IT APPROACHES OVERNIGHT
SUNDAY...PERHAPS BRINGING SOME LIGHT RAIN AT TIMES...PARTICULARLY IN
SW WASHINGTON...BUT IN LIMITED AMOUNTS. MONDAY MAY BE DRY AS UPPER
LEVEL RIDGE AXIS MOVES OVER THE AREA...BUT THE NEXT FRONT WILL
ARRIVE TUESDAY FOR ANOTHER ROUND OF PRECIPITATION. THIS WILL BE IN
THE FORM OF RAIN FOR MOST LOCATIONS AS SNOW LEVELS WILL RISE ABOVE
6000 FEET BY LATE MONDAY BEFORE THE BULK OF THE MOISTURE ARRIVES.
&&
.AVIATION...A WARM FRONT LIFTING NORTH TONIGHT. THIS IS BRINGING
LIGHT RAIN AND STEADILY LOWERING CIGS. CONDITIONS MOSTLY VFR AT
CURRENT WITH CIG HEIGHTS 4 TO 5 KFT. HOWEVER...CIGS TO CONTINUE
TO LOWER TONIGHT AS THE WARM FRONT MOVES THROUGH...WITH MVFR CIGS
OF 25OO TO 3000 KFT LIKELY DEVELOPING AT THE COAST AND FOR THE
NORTH INTERIOR. EXPECT MAINLY VFR WITH LITTLE IN THE WAY OF RAIN
FOR THE INTERIOR ROUGHLY SOUTH OF KSLE. CONDITIONS SHOULD IMPROVE
TO MOSTLY VFR AGAIN FOR MOST OF TOMORROW. A COLD FRONT TO MOVE
ONSHORE TOMORROW NIGHT INTO EARLY FRI MORNING. EXPECT STEADIER
RAIN AND MVFR CONDITIONS TO DEVELOP AT THE COAST IN THE EVENING
HOURS...THEN INLAND OVERNIGHT.
HAVE WIND SHEAR CONCERNS AFTER 09Z FOR KTTD AND KPDX AS SURFACE
FLOW WILL BE EASTERLY FROM THE GORGE WHILE FLOW ALOFT WILL
INCREASE FROM THE SOUTH. SOUTHERLY WINDS MAY GUST 25 TO 30 KT FOR
THE COASTAL TAF SITES OVERNIGHT AND MUCH OF TOMORROW.
KPDX AND APPROACHES...LIGHT RAIN WITH CIGS 4 TO 5 KFT THROUGH THIS
EVENING. EXPECT LIGHT RAIN TO CONTINUE OVERNIGHT...WITH CIGS
LIKELY LOWERING TO AROUND 3 KFT BY 09Z TO 12Z. CONDITIONS SHOULD
RETURN TO MAINLY VFR BY MID TO LATE MORNING THU...AND REMAIN VFR
THROUGH THE DAY. STEADIER RAIN AND MVFR CONDITIONS LIKELY RETURN
LATER THU NIGHT. PYLE
&&
.MARINE...A STRONG OCCLUDING LOW PRES SYSTEM IS LOCATED NEAR
50N/145W THIS EVENING. THIS SYSTEM IS CURRENTLY BRINGING A WARM FRONT
NORTHWARD THROUGH THE WATERS...WITH ASSOCIATED GUSTY SOUTHEASTERLY
WINDS PICKING UP OVER THE PAST SEVERAL HOURS. THE LATEST
OBSERVATIONS NOW SHOWING GALE FORCE WINDS OVER THE OUTER WATERS.
EXPECT SOUTHERLY WINDS 30 TO 35 KT WITH GUSTS 40 TO 45 KT TO
CONTINUE THROUGH THU EVENING BEYOND 10 NM OFFSHORE. THE OFFSHORE
COMPONENT TO THE PRES GRADIENT TO KEEP THE STRONGER WINDS FROM
REACHING THE NEAR SHORE WATERS...WHERE A SMALL CRAFT ADVISORY
SHOULD BE SUFFICIENT. A TRAILING COLD FRONT WILL PUSH THROUGH THE
WATERS LATE THU NIGHT OR EARLY FRI MORNING...WITH WINDS SHIFTING
TO THE SW AND DROPPING OFF CONSIDERABLY BEHIND THE FRONT.
ANOTHER LOW PRES SYSTEM TO APPROACH THE S OREGON OR N CALIF COAST
FRI NIGHT INTO SAT...BUT THIS SYSTEM IS NOT CURRENTLY EXPECT TO
BRING SIGNIFICANT IMPACTS FOR THE S WASHINGTON AND N OREGON
COASTAL WATERS. HOWEVER...THERE IS STILL SOME UNCERTAINTY ON
EXACTLY WHERE THE SURFACE LOW WILL TRACK...WITH A FURTHER NORTH
TRACK LIKE THE GFS POTENTIALLY BRINGING SOME GUSTIER WINDS INTO
THE CENTRAL OREGON WATERS. HIGH PRES BUILDS OVER THE WATERS LATER
IN THE WEEKEND. THE NEXT SYSTEM ARRIVES AT SOME POINT EARLY NEXT
WEEK.
SEAS ARE RUNNING IN THE LOW TEENS THIS EVENING. WILL SEE SEAS
INCREASE OVERNIGHT AS GUSTY SOUTHERLY WINDS CONTINUE TO
BLOW...BUILDING
INTO THE MID TEENS LATE TONIGHT AND LIKELY PEAKING IN THE UPPER
TEENS LATER THURSDAY. SEAS SUBSIDE BACK TO THE MID TEENS BY
FRIDAY AND LOOK TO FALL BELOW 10 FT SOMETIME THIS WEEKEND. PYLE
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...GALE WARNING UNTIL 10 PM PST THURSDAY FOR WATERS FROM CAPE
SHOALWATER WA TO CASCADE HEAD OR FROM 10 TO 60 NM-WATERS
FROM CASCADE HEAD TO FLORENCE OR FROM 10 TO 60 NM.
SMALL CRAFT ADVISORY FOR WINDS UNTIL 10 PM PST THURSDAY FOR
COASTAL WATERS FROM CAPE SHOALWATER WA TO CASCADE HEAD OR
OUT 10 NM-COASTAL WATERS FROM CASCADE HEAD TO FLORENCE OR
OUT 10 NM.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 10 PM PST
THURSDAY FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO CASCADE
HEAD OR OUT 10 NM-COASTAL WATERS FROM CASCADE HEAD TO FLORENCE
OR OUT 10 NM.
SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR UNTIL 10 PM
PST THURSDAY.
&&
$$
INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/NWSPORTLAND
WWW.TWITTER.COM/NWSPORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON
FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS
COMMONLY REFERRED TO AS THE FORECAST AREA.
Area Forecast Discussion
National Weather Service Spokane WA
816 PM PST WED JAN 20 2016
.SYNOPSIS...
A slow moving frontal system will bring locally heavy snow to the
Cascades and the Methow Valley tonight into Thursday. The front
will gradually move through eastern Washington and north Idaho on
Friday bringing light rain. Saturday will also feature the
potential for rain and mountain snow. High pressure should produce
mainly dry conditions Sunday and Monday before more valley rain
and mountain snow returns Tuesday.
&&
.DISCUSSION...
Evening update to bring precipitation into the Wenatchee area,
Waterville Plateau and lower basin a bit earlier based on current
radar trends. Overnight low temperatures were also adjusted since
the areas that saw some breaks in the clouds after sunset had
already dropped below forecast low temps. The shield of
precipitation associated with an advancing warm front is spreading
into the southwest portion of the forecast area this evening.
Right now temperatures are right at or a degree or two above the
freezing mark from the Moses Lake area northward. Current thinking
is that temperatures should rise a couple of degrees as warm air
pushes in from the south. Temps to our south in south central WA
have risen a bit as winds shift to the south. This should keep
precipitation type as rain in the basin north to Highway 2. Model
soundings are still showing the potential for some freezing rain
to develop in the Wenatchee area as well as some of the east slope
valleys. We will be keeping a close eye on these areas tonight for
possible winter highlights if freezing rain does occur. /Kelch
&&
.AVIATION...
00Z TAFS: A warm front will bring our next round of precipitation
to the Inland Northwest tonight into Thursday. Precipitation may
begin as light snow at Wenatchee, Coeur d`Alene, and Chelan, but
should transition to rain. As with most moist frontal systems this
time of year, precipitation will likely be accompanied by low
clouds and visibility restrictions especially in the 12z-20z time
frame. /GKoch
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 31 42 36 42 33 39 / 20 50 20 60 40 50
Coeur d`Alene 29 41 35 42 33 39 / 10 50 20 70 50 50
Pullman 34 46 38 46 34 40 / 10 20 10 60 40 50
Lewiston 36 51 41 50 37 44 / 10 20 10 30 30 50
Colville 32 39 34 40 33 37 / 30 80 50 60 40 40
Sandpoint 32 38 35 40 33 38 / 20 60 20 80 60 50
Kellogg 31 40 36 40 31 36 / 10 40 20 70 60 60
Moses Lake 33 43 34 44 32 40 / 30 50 30 40 20 50
Wenatchee 32 39 35 42 31 37 / 90 90 80 90 20 50
Omak 31 36 33 39 29 35 / 70 100 80 90 20 40
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Winter Storm Warning until 10 AM PST Friday for East Slopes
Northern Cascades.
&&
$$
Area Forecast Discussion
National Weather Service Spokane WA
816 PM PST WED JAN 20 2016
.SYNOPSIS...
A slow moving frontal system will bring locally heavy snow to the
Cascades and the Methow Valley tonight into Thursday. The front
will gradually move through eastern Washington and north Idaho on
Friday bringing light rain. Saturday will also feature the
potential for rain and mountain snow. High pressure should produce
mainly dry conditions Sunday and Monday before more valley rain
and mountain snow returns Tuesday.
&&
.DISCUSSION...
Evening update to bring precipitation into the Wenatchee area,
Waterville Plateau and lower basin a bit earlier based on current
radar trends. Overnight low temperatures were also adjusted since
the areas that saw some breaks in the clouds after sunset had
already dropped below forecast low temps. The shield of
precipitation associated with an advancing warm front is spreading
into the southwest portion of the forecast area this evening.
Right now temperatures are right at or a degree or two above the
freezing mark from the Moses Lake area northward. Current thinking
is that temperatures should rise a couple of degrees as warm air
pushes in from the south. Temps to our south in south central WA
have risen a bit as winds shift to the south. This should keep
precipitation type as rain in the basin north to Highway 2. Model
soundings are still showing the potential for some freezing rain
to develop in the Wenatchee area as well as some of the east slope
valleys. We will be keeping a close eye on these areas tonight for
possible winter highlights if freezing rain does occur. /Kelch
&&
.AVIATION...
00Z TAFS: A warm front will bring our next round of precipitation
to the Inland Northwest tonight into Thursday. Precipitation may
begin as light snow at Wenatchee, Coeur d`Alene, and Chelan, but
should transition to rain. As with most moist frontal systems this
time of year, precipitation will likely be accompanied by low
clouds and visibility restrictions especially in the 12z-20z time
frame. /GKoch
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 31 42 36 42 33 39 / 20 50 20 60 40 50
Coeur d`Alene 29 41 35 42 33 39 / 10 50 20 70 50 50
Pullman 34 46 38 46 34 40 / 10 20 10 60 40 50
Lewiston 36 51 41 50 37 44 / 10 20 10 30 30 50
Colville 32 39 34 40 33 37 / 30 80 50 60 40 40
Sandpoint 32 38 35 40 33 38 / 20 60 20 80 60 50
Kellogg 31 40 36 40 31 36 / 10 40 20 70 60 60
Moses Lake 33 43 34 44 32 40 / 30 50 30 40 20 50
Wenatchee 32 39 35 42 31 37 / 90 90 80 90 20 50
Omak 31 36 33 39 29 35 / 70 100 80 90 20 40
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Winter Storm Warning until 10 AM PST Friday for East Slopes
Northern Cascades.
&&
$$
Area Forecast Discussion
National Weather Service Spokane WA
816 PM PST WED JAN 20 2016
.SYNOPSIS...
A slow moving frontal system will bring locally heavy snow to the
Cascades and the Methow Valley tonight into Thursday. The front
will gradually move through eastern Washington and north Idaho on
Friday bringing light rain. Saturday will also feature the
potential for rain and mountain snow. High pressure should produce
mainly dry conditions Sunday and Monday before more valley rain
and mountain snow returns Tuesday.
&&
.DISCUSSION...
Evening update to bring precipitation into the Wenatchee area,
Waterville Plateau and lower basin a bit earlier based on current
radar trends. Overnight low temperatures were also adjusted since
the areas that saw some breaks in the clouds after sunset had
already dropped below forecast low temps. The shield of
precipitation associated with an advancing warm front is spreading
into the southwest portion of the forecast area this evening.
Right now temperatures are right at or a degree or two above the
freezing mark from the Moses Lake area northward. Current thinking
is that temperatures should rise a couple of degrees as warm air
pushes in from the south. Temps to our south in south central WA
have risen a bit as winds shift to the south. This should keep
precipitation type as rain in the basin north to Highway 2. Model
soundings are still showing the potential for some freezing rain
to develop in the Wenatchee area as well as some of the east slope
valleys. We will be keeping a close eye on these areas tonight for
possible winter highlights if freezing rain does occur. /Kelch
&&
.AVIATION...
00Z TAFS: A warm front will bring our next round of precipitation
to the Inland Northwest tonight into Thursday. Precipitation may
begin as light snow at Wenatchee, Coeur d`Alene, and Chelan, but
should transition to rain. As with most moist frontal systems this
time of year, precipitation will likely be accompanied by low
clouds and visibility restrictions especially in the 12z-20z time
frame. /GKoch
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 31 42 36 42 33 39 / 20 50 20 60 40 50
Coeur d`Alene 29 41 35 42 33 39 / 10 50 20 70 50 50
Pullman 34 46 38 46 34 40 / 10 20 10 60 40 50
Lewiston 36 51 41 50 37 44 / 10 20 10 30 30 50
Colville 32 39 34 40 33 37 / 30 80 50 60 40 40
Sandpoint 32 38 35 40 33 38 / 20 60 20 80 60 50
Kellogg 31 40 36 40 31 36 / 10 40 20 70 60 60
Moses Lake 33 43 34 44 32 40 / 30 50 30 40 20 50
Wenatchee 32 39 35 42 31 37 / 90 90 80 90 20 50
Omak 31 36 33 39 29 35 / 70 100 80 90 20 40
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Winter Storm Warning until 10 AM PST Friday for East Slopes
Northern Cascades.
&&
$$
Area Forecast Discussion
National Weather Service Spokane WA
354 PM PST WED JAN 20 2016
.SYNOPSIS...
A slow moving frontal system will bring locally heavy snow to the
Cascades and the Methow Valley tonight into Thursday. The front
will gradually move through eastern Washington and north Idaho on
Friday bringing light rain. Saturday will also feature the
potential for rain and mountain snow. High pressure should produce
mainly dry conditions Sunday and Monday before more valley rain
and mountain snow returns Tuesday.
&&
.DISCUSSION...
...HEAVY MOUNTAIN SNOW AND WINTRY MIX EAST SLOPES OF CASCADES
TONIGHT THROUGH FRIDAY MORNING...
Tonight through Friday morning: Satellite imagery shows the next
weather system knocking on our doorstep. The upper level low
pressure circulation is located out at 50N 135W in the Gulf of
Alaska. This low pressure system is tapping into a sub-tropical
moisture plume that extends out to the Hawaiian Islands. The
upper level trough will continue to dig as it approaches the
region. This will act to orient the moisture plume more
meridionally more along the western coast line. The warm front
currently pushing its way into northwest OR with light rain being
observed on radar along the coast. This front is progged to reach
the northern Cascades between 8:00 and 10:00 PM this evening based
off the latest HRRR guidance. Much of the region will see at least
a chance for some light precipitation as the front crosses eastern
WA and into the ID Panhandle overnight.
A southeasterly pressure gradient will strengthen overnight. This
will result in some downsloping off of the Northeast Blue Mtns and
off of the higher terrain in the ID Panhandle. I anticipate that
that this will act to hinder much precipitation from actually
reaching the ground across the Palouse, into the Lewiston-
Clarkston Vly and up on the Camas Prairie. Generally only some
light precipitation is anticipated with the warm front across much
of eastern WA and in the ID Panhandle.
Areas that will benefit from the easterly gradient will be the
East Slopes of the Northern Cascades. The combination of moist
isentropic ascent and orographics should keep these areas wet.
Snow levels are going to be very tricky with this system.
Valleys that saw some sun across this area this afternoon should
have a difficult time cooling back down below freezing overnight.
Higher clouds are already moving in and this should act to keep
this warmer air from radiating completely away. However, the
Okanogan Valley and Methow Valley continue to see low clouds,
which has kept their temperatures down in the low 30s. These
locations will see a better chance for accumulating snow;
although, I am not as confidence about the Okanogan Valley. I
think surface temperatures will be too warm for much of the
Wenatchee Area for snow to stick, especially right along the
Columbia River. I also think that Wenatchee River Valley, Entiat
River Valley and communities along Lake Chelan will have a
difficult time seeing snow accumulate. The Winter Storm Watch will
be upgraded to a Warning for heavy snow, but will largely only
includes locations below 3000 feet south of Lake Chelan. The upper
reaches of the Methow Valley will also see a good chance for heavy
snow accumulations. The warning will run from tonight and continue
into Friday morning until the cold front passes through. I also
kept a possibility for freezing rain in the east slopes of the
northern Cascades and colder pockets in the Wenatchee Area. My
confidence is low since way did see some warming today, but cannot
completely rule it out. /SVH
Friday: The frontal system hung up along the Cascades Thursday and
Thursday night will finally be shoved eastward on Friday. There
will be a good deal of deep layer moisture accompanying the front
as it moves through eastern Washington and north Idaho, but not a
lot of large scale forcing. The models hardly depict a surface low
with the weak 500mb shortwave trough...an indication of weak
forcing. So despite an abundance of moisture, precipitation
amounts will be relatively light compared to some of our recent
storm systems. Snow levels will be high Friday and Friday night
with lowland communities region-wide receiving rain. One area of
exception could be the Methow Valley where the NAM and GFS depict
a bit of cooler air trapped along the Cascades which could
contribute to light snow accumulations Friday morning.
Saturday and Sunday: Saturday has the potential to be cool and wet
as a weakening upper low moves into Oregon and falls apart. The
GFS and Canadian models sustain a weak deformation band Saturday
into Saturday night which produces a tenth to a quarter of an inch
or precipitation for eastern Washington and north Idaho. The NAM
and ECMWF split this feature suggesting lower precipitation
chances for our region Saturday. This system bears watching since
snow levels will be marginal for accumulations in the lee of the
Cascades into portions of Washington and Idaho near the Canadian
border. However, given the daytime arrival of precipitation, snow
may struggle to accumulate on roads. There is good model agreement
that Sunday will be drier with orographic snow showers mainly
limited to the mountains of the Idaho Panhandle. The sun may even
make an appearance Sunday along the east slopes of the Cascades
into portions of the Columbia Basin. /GKoch
Sunday night through Wednesday...Models are in good agreement of
an upper level ridge over the region Sunday night through Monday
night. This should result in dry conditions with areas of low
clouds and patchy fog in the valleys and Columbia Basin. The ridge
moves east on Tuesday allowing a weak short wave trough to pass
through the Inland NW bringing with it a chance for light rain and
snow. GFS Ensembles show quite a bit of spread regarding the
timing of this wave and would not be surprised to see the timing
delayed until Tuesday night or Wednesday. Models then show a
milder and wetter system for next Wednesday or Thursday. Near to
slightly above normal temperatures are expected in the extended
forecast period. JW
&&
.AVIATION...
00Z TAFS: A warm front will bring our next round of precipitation
to the Inland Northwest tonight into Thursday. Precipitation may
begin as light snow at Wenatchee, Coeur d`Alene, and Chelan, but
should transition to rain. As with most moist frontal systems this
time of year, precipitation will likely be accompanied by low
clouds and visibility restrictions especially in the 12z-20z time
frame. /GKoch
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 34 42 36 42 33 39 / 20 50 20 60 40 50
Coeur d`Alene 33 41 35 42 33 39 / 10 50 20 70 50 50
Pullman 35 46 38 46 34 40 / 10 20 10 60 40 50
Lewiston 36 51 41 50 37 44 / 10 20 10 30 30 50
Colville 32 39 34 40 33 37 / 30 80 50 60 40 40
Sandpoint 32 38 35 40 33 38 / 20 60 20 80 60 50
Kellogg 31 40 36 40 31 36 / 10 40 20 70 60 60
Moses Lake 34 43 34 44 32 40 / 30 50 30 40 20 50
Wenatchee 34 39 35 42 31 37 / 90 90 80 90 20 50
Omak 32 36 33 39 29 35 / 70 100 80 90 20 40
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Winter Storm Warning from 10 PM this evening to 10 AM PST Friday
for East Slopes Northern Cascades.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS TAMPA BAY RUSKIN FL
542 AM EST THU JAN 21 2016
...HAZARDOUS AND VERY ROUGH BOATING CONDITIONS EXPECTED LATE
FRIDAY THROUGH SATURDAY FOR THE COASTAL WATERS OF WEST-CENTRAL AND
SOUTHWEST FLORIDA...
...HIGH SURF AND DANGEROUS RIP CURRENTS EXPECTED FRIDAY NIGHT
THROUGH SATURDAY NIGHT ALONG THE BEACHES OF WEST-CENTRAL AND
SOUTHWEST FLORIDA...
.SYNOPSIS...
10Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS AN AMPLIFIED UPPER LEVEL
PATTERN IN PLACE ACROSS THE CONUS THIS MORNING. SHARP RIDGING HAS
MOVED ASHORE ALONG THE PACIFIC COAST AND IS SPREADING INLAND OVER
THE INTER-MOUNTAIN WEST. DOWNSTREAM THE FLOW DIPS QUICKLY INTO A
POTENT SHORTWAVE TROUGH DIGGING THROUGH THE CENTRAL AND SOUTHERN
PLAINS. IT WILL BE THIS ENERGY THAT CONTINUES TO DIG SOUTHWARD TO
THE NORTHERN GULF COAST DURING THE NEXT 24 HOURS...AND BRINGS A
ROUND OF RAIN/THUNDERSTORMS TO THE REGION DURING FRIDAY. BY THE
END OF FRIDAY AND THROUGH THE FIRST HALF OF THE UPCOMING
WEEKEND...THIS DEVELOPING STORM SYSTEM IS FORECAST TO BRING A VERY
SIGNIFICANT WINTER STORM TO PORTIONS OF THE EASTERN
CONUS...INCLUDING SOME OF THE MAJOR CITIES OF THE MID-ATLANTIC AND
NORTHEASTERN STATES. WINTER HELD OFF FOR A WHILE THIS YEAR...AT
LEAST IN TERMS OF SNOWFALL OVER MUCH OF THE EASTERN STATES...BUT
EVENTUALLY THE SEASONS CATCH UP.
CLOSER TO HOME...THE UPPER LEVEL FLOW IS CURRENTLY IN A ZONAL
CONFIGURATION...AND THIS PATTERN WILL HOLD FOR THE REMAINDER OF
TODAY. SHOULD EVEN SEE SOME TENDENCY TOWARD RIDGING ALOFT TODAY IN
RESPONSE TO THE SIGNIFICANT UPSTREAM HEIGHT FALLS ARRIVING OVER
THE NORTHWEST GULF. STRONG HIGH LEVEL SOUTHERN STREAM JET
CROSSING OVER THE PENINSULA IS RESULTING IN SOME PASSING HIGH
LEVEL CIRRUS...AND SHOULD CONTINUE TO SEE THESE HIGHER CLOUDS TO
FILTER THE SUN THROUGH MUCH OF THE DAY. HOWEVER...AS MENTIONED
ABOVE...CONDITIONS WILL CHANGE QUICKLY LATE TONIGHT INTO FRIDAY AS
THE ENERGY CONTINUES TO AMPLIFY AND TRANSLATE EASTWARD INTO OUR
REGION.
AT THE SURFACE...HIGH PRESSURE IS IN CONTROL OF THE FLORIDA
PENINSULA...BUT WILL BE SHIFTING EASTWARD WITH TIME TODAY INTO THE
WESTERN ATLANTIC. SEASONABLY COOL MORNING ONGOING ACROSS THE
REGION WITH TEMPERATURES RANGING FROM FROSTY MIDDLE 30S OVER THE
FAR NORTHERN ZONES TO THE 40S/LOWER 50S ELSEWHERE.
&&
.SHORT TERM (TODAY THROUGH FRIDAY)...
TODAY THROUGH TONIGHT...FAIR...DRY AND SEASONABLE CONDITIONS TO
BE EXPECTED THROUGH THE DAYLIGHT HOURS. STARTING OUT ON THE COLD
SIDE OVER PORTIONS OF THE NATURE COAST...HOWEVER...PLENTY OF SUN
WILL ALLOW TEMPERATURES TO RECOVER QUICKLY THROUGH THE MORNING
HOURS. LOOKING FOR HIGH TEMPS THIS AFTERNOON TO REACH THE UPPER
60S/LOWER 70S NORTH AND LOWER/MID 70S SOUTH UNDER A MIX OF SUN AND
HIGH CLOUDS. LIGHT WINDS BECOME SOUTHEAST THROUGH THE DAY.
EVEN TONIGHT...CONDITIONS ARE EXPECTED TO REMAIN MOSTLY DRY. GOOD
AGREEMENT AMONG THE GUIDANCE MEMBERS THAT THE MAIN SYNOPTIC
FORCING AND SUFFICIENT MOISTENING TO COMMENCE OUR RAIN CHANCES
WILL NOT ARRIVE UNTIL VERY LATE TONIGHT...AND MORE LIKELY AFTER
SUNRISE FRIDAY MORNING. SO...FOR THE OVERNIGHT...EXPECT MOSTLY DRY
CONDITIONS...WITH INCREASING CLOUDS. THE POTENT UPPER LEVEL
DISTURBANCE WILL BE QUICKLY APPROACHING ACROSS THE NORTHERN GULF
COAST WITH ASSOCIATED SURFACE LOW PRESSURE MOVING FROM THE LOWER
MS VALLEY TO THE TN VALLEY. A STRONG COLD FRONT TRAILING SOUTHWARD
FROM THIS LOW WILL BE ALSO QUICKLY TRANSLATING EASTWARD ACROSS THE
GULF OF MEXICO. EXPECT WINDS TO INCREASE OUT OF THE SOUTH AND
SOUTHEAST AHEAD OF THIS FRONT...ESPECIALLY OVER THE COASTAL
WATERS.
FRIDAY...CONDITIONS ARE LIKELY TO GO DOWNHILL QUICKLY FRIDAY
MORNING. GFS/ECMWF BOTH SHOW HEIGHT FALLS COMMENCING...WITH A
BROAD AND IMPRESSIVE SWATH OF DEEP LAYER QVECTOR CONVERGENCE
OVERSPREADING THE REGION BY MIDDAY. THIS BROAD SYNOPTIC FORCING
FOR LIFT WILL LIE UNDERNEATH A HIGHLY DIFFLUENCE FLOW
ALOFT...FURTHER AIDING THE UPWARD MOTION. THEREFORE...EXPECT A
BAND...OR BANDS OF SHOWERS AND EMBEDDED STORMS TO QUICKLY
APPROACH THE FLORIDA WEST COAST FRIDAY MORNING... AND THEN SPREAD
INLAND THROUGH MIDDAY/EARLY AFTERNOON. HAVE GONE WITH CATEGORICAL
RAIN CHANCES FOR ALL ZONES FRIDAY MORNING/EARLY AFTERNOON. THE
PASSAGE OF THE COLD FRONT MIDDAY FRIDAY INTO FRIDAY AFTERNOON
SHOULD END THE ORGANIZED RAIN FROM WEST TO EAST. IF THE GFS IS
CORRECT...THEN MUCH OF THE STEADIER SHOWER CHANCES WILL BE MOVING
EAST OF OUR REGION AFTER 17-19Z. EVEN THOUGH THE PRE-FRONTAL RAIN
WILL BE OVER BY LATE IN THE DAY...CAN NOT COMPLETELY REMOVE RAIN
CHANCES INTO FRIDAY NIGHT (ESPECIALLY CLOSE TO THE COAST) AS
STRONG COLD AIR ADVECTION AND CONTINUED STRONG PVA ALOFT SHOULD BE
ENOUGH TO SUPPORT MORE SCT AND SHALLOW SHOWER ACTIVITY MOVING OFF
THE EASTERN GULF.
THERE IS SOME POTENTIAL FOR A FEW STRONG THUNDERSTORMS FRIDAY
AHEAD OF THIS COLD FRONT...HOWEVER THE THREAT FOR SEVERE WEATHER
WITH THIS SYSTEM APPEARS MUCH GREATER TO THE NORTHWEST OF OUR
REGION...MOSTLY ACROSS THE FLORIDA PANHANDLE. CONDITIONS CERTAINLY
DO NOT APPEAR AS VOLATILE AS THEY WERE WITH THE EVENT THIS PAST
WEEKEND. THE STORM PREDICTION CENTER HAS OUTLOOKED AT THIS
TIME...ONLY LEVY COUNTY IN A MARGINAL RISK FOR SEVERE WEATHER. NO
ZONES FURTHER SOUTH ARE CURRENTLY OUTLOOKED WITH A RISK FOR
ORGANIZED SEVERE WEATHER. HOWEVER...WE CAN NEVER LET OUR GUARD
DOWN. THE WIND FIELDS ARE STILL SUFFICIENT FOR A FEW STRONGER
STORMS...WITH FREQUENT LIGHTNING AND GUSTY WINDS THE MAIN HAZARDS.
FORECASTERS WILL CERTAINLY BE WATCHING/MONITORING THE SITUATION
CLOSELY EARLY FRIDAY AS THE STORMS APPROACH THE COAST.
&&
.LONG TERM (FRIDAY NIGHT - WEDNESDAY)...
THE PERIOD BEGINS WITH AN UPPER TROUGH CENTERED OVER THE TN/AL/GA
BORDER THAT HAS A SURFACE REFLECTION ALONG THE GA/SC
LINE...TRAILING A COLD FRONT SOUTHWARD ACROSS EAST CENTRAL FL AND
SOUTH FL. THESE FEATURES MOVE EAST FRI NIGHT THEN OFFSHORE SAT. AN
UPPER RIDGE MOVES INTO THE MID- CONUS AS SURFACE HIGH PRESSURE
BUILDS OVER THE SOUTHERN PLAINS. THESE AND THE DEPARTING FEATURES
MAINTAIN A TIGHT PRESSURE GRADIENT WITH STRONG WEST AND NORTHWEST
WINDS CREATING MARINE AND COASTAL ISSUES. COLD AIR MOVING ACROSS
THE WARMER GULF WATERS ALONG THE TROUGHINESS DOWN OVER THE GULF
WILL SUPPORT SLIGHT CHANCE TO CHANCE SHOWERS THAT WIND DOWN DURING
SAT.
SUN AND MON - THE UPPER RIDGE AND SURFACE HIGH PRESSURE TRACK EAST...
ACROSS THE GULF COAST AND SOUTHEASTERN STATES TO THE ATLANTIC. A COLD
DRY STABLE AIR MASS SPREADS ACROSS THE AREA WITH NORTHWESTERLY WINDS.
TEMPERATURES WILL BE AT OR NEAR FREEZING FOR THE NATURE COAST EARLY
SUN MORNING WITH POSSIBLE CRITICAL WIND CHILLS DOWN INTO THE
CENTRAL COUNTIES. AS THE HIGH MOVES BY WINDS DIMINISH AND BECOME
MORE NORTHEASTERLY WITH TEMPERATURES MODERATING.
TUE-WED - THE SURFACE HIGH CONTINUE TO MOVE EAST BUT RIDGE BACK TO FL
INITIALLY. AN UPPER TOUGH WITH AN ATTENDANT COLD FRONT SETTLES INTO THE
MISSISSIPPI VALLEY TUE THEN SHIFTS TO THE EASTERN SEABOARD AND NORTHERN
FL WED. THE ATMOSPHERE WARMS AND MOISTENS WHICH WITH THE APPROACHING
FRONT WILL SUPPORT SOME SLIGHT CHANCE SHOWER TUE THAT INCREASE TO
CHANCE BUT OCCASIONALLY LIKELY WED.
&&
.AVIATION... VFR CONDITIONS OBSERVED ACROSS WEST-CENTRAL AND
SOUTHWEST FLORIDA EARLY THIS MORNING. SLIGHT CHANCE FOR A BRIEF
PERIOD OF MVFR GROUND FOG AT LAL TOWARD SUNRISE...BUT OTHERWISE VFR
CONDITIONS PREVAIL THROUGH AT LEAST THE EVENING HOURS.
OVERNIGHT...COLD FRONT WILL APPROACH WITH A BAND OF SHOWERS AND
STORMS...HOWEVER CURRENTLY APPEARS AS THOUGH ANY VIS/CIG
RESTRICTIONS ASSOCIATED WITH THIS FRONTAL PASSAGE WILL HOLD OFF
UNTIL AFTER 12Z FRIDAY.
&&
.MARINE...
HIGH PRESSURE MOVES EASTWARD TODAY ALLOWING WINDS TO SHIFT TO THE
SOUTHEAST. A STRONG COLD FRONT WILL THEN APPROACH THE EASTERN GULF
OF MEXICO OVERNIGHT AND CROSS THE REGION FRIDAY MORNING THROUGH
EARLY AFTERNOON. SOUTHERLY WINDS WILL INCREASE TO AT LEAST
CAUTIONARY LEVELS OVERNIGHT...WITH SOME POTENTIAL FOR ADVISORY
LEVEL WINDS OVER THE OFFSHORE WATERS AFTER MIDNIGHT. WINDS SHIFT
TO THE WEST AND NORTHWEST IN THE WAKE OF THE FRONT LATER FRIDAY
AND RAPIDLY INCREASE TO ADVISORY LEVELS OVER ALL THE FORECAST
WATERS BY FRIDAY EVENING. A PERIOD OF VERY ROUGH AND HAZARDOUS
BOATING CONDITIONS IS EXPECTED OVER THE FORECAST WATERS FRIDAY
NIGHT THROUGH SATURDAY. NORTHWEST WINDS ARE LIKELY TO GUST OVER
GALE FORCE AT TIMES THROUGH SATURDAY MORNING. WINDS WILL SLOWLY
SUBSIDE SATURDAY NIGHT INTO SUNDAY MORNING AS HIGH PRESSURE
BUILDS OVER THE REGION. HOWEVER...RESIDUAL SEAS WILL BE SLOWER TO
DROP BELOW ADVISORY LEVELS...RESULTING IN HEADLINES LIKELY
CONTINUING FOR PORTIONS OF THE WATERS THROUGH SATURDAY NIGHT.
&&
.FIRE WEATHER...
HIGH PRESSURE WILL SHIFT EASTWARD TODAY ALLOWING WINDS TO COME
AROUND TO THE SOUTHEAST. THE SOUTHEAST WIND WILL BEGIN THE
BRINGING A SLOW INCREASE IN MOISTURE TO THE REGION. RELATIVE
HUMIDITY VALUES ARE FORECAST TO BRIEFLY FALL BELOW 35 PERCENT
ACROSS PORTION OF THE NORTHERN NATURE COAST...BUT ELSEWHERE
SHOULD REMAIN GENERALLY ABOVE CRITICAL LEVELS. A COLD FRONT
WILL APPROACH AND CROSS THE REGION DURING THE DAYLIGHT HOURS
OF FRIDAY WITH MOST LOCATIONS RECEIVING A WETTING RAINFALL.
WINDS SHIFT TO THE NORTHWEST BEHIND THE FRONT AND BECOME VERY
GUSTY FRIDAY NIGHT INTO SATURDAY. THESE WINDS WILL ALSO DELIVER
A MUCH COLDER AIRMASS TO THE REGION FOR SATURDAY AND SATURDAY
NIGHT.
FOG POTENTIAL...
PATCHY FOG WILL BE AROUND THE REGION EARLY THIS MORNING. NO
ADDITIONAL FOG CONCERNS ARE ANTICIPATED THROUGH SATURDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 72 58 70 52 / 0 0 90 30
FMY 75 59 73 57 / 0 10 90 20
GIF 73 57 72 50 / 0 0 90 20
SRQ 71 59 70 56 / 0 10 90 30
BKV 73 55 69 48 / 0 0 90 30
SPG 71 59 69 53 / 0 0 90 30
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
SYNOPSIS/SHORT TERM/AVIATION/MARINE/FIRE WX...MROCZKA
LONG TERM/DECISION SUPPORT...RUDE
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
537 AM EST THU JAN 21 2016
...HAZARDOUS AND VERY ROUGH BOATING CONDITIONS EXPECTED LATE
FRIDAY THROUGH SATURDAY FOR THE COASTAL WATERS OF WEST-CENTRAL AND
SOUTHWEST FLORIDA...
...HIGH SURF AND DANGEROUS RIP CURRENTS EXPECTED FRIDAY NIGHT
THROUGH SATURDAY NIGHT ALONG THE BEACHES OF WEST-CENTRAL AND
SOUTHWEST FLORIDA...
.SYNOPSIS...
10Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS AN AMPLIFIED UPPER LEVEL
PATTERN IN PLACE ACROSS THE CONUS THIS MORNING. SHARP RIDGING HAS
MOVED ASHORE ALONG THE PACIFIC COAST AND IS SPREADING INLAND OVER
THE INTER-MOUNTAIN WEST. DOWNSTREAM THE FLOW DIPS QUICKLY INTO A
POTENT SHORTWAVE TROUGH DIGGING THROUGH THE CENTRAL AND SOUTHERN
PLAINS. IT WILL BE THIS ENERGY THAT CONTINUES TO DIG SOUTHWARD TO
THE NORTHERN GULF COAST DURING THE NEXT 24 HOURS...AND BRINGS A
ROUND OF RAIN/THUNDERSTORMS TO THE REGION DURING FRIDAY. BY THE
END OF FRIDAY AND THROUGH THE FIRST HALF OF THE UPCOMING
WEEKEND...THIS DEVELOPING STORM SYSTEM IS FORECAST TO BRING A VERY
SIGNIFICANT WINTER STORM TO PORTIONS OF THE EASTERN
CONUS...INCLUDING SOME OF THE MAJOR CITIES OF THE MID-ATLANTIC AND
NORTHEASTERN STATES. WINTER HELD OFF FOR A WHILE THIS YEAR...AT
LEAST IN TERMS OF SNOWFALL OVER MUCH OF THE EASTERN STATES...BUT
EVENTUALLY THE SEASONS CATCH UP.
CLOSER TO HOME...THE UPPER LEVEL FLOW IS CURRENTLY IN A ZONAL
CONFIGURATION...AND THIS PATTERN WILL HOLD FOR THE REMAINDER OF
TODAY. SHOULD EVEN SEE SOME TENDENCY TOWARD RIDGING ALOFT TODAY IN
RESPONSE TO THE SIGNIFICANT UPSTREAM HEIGHT FALLS ARRIVING OVER
THE NORTHWEST GULF. STRONG HIGH LEVEL SOUTHERN STREAM JET
CROSSING OVER THE PENINSULA IS RESULTING IN SOME PASSING HIGH
LEVEL CIRRUS...AND SHOULD CONTINUE TO SEE THESE HIGHER CLOUDS TO
FILTER THE SUN THROUGH MUCH OF THE DAY. HOWEVER...AS MENTIONED
ABOVE...CONDITIONS WILL CHANGE QUICKLY LATE TONIGHT INTO FRIDAY AS
THE ENERGY CONTINUES TO AMPLIFY AND TRANSLATE EASTWARD INTO OUR
REGION.
AT THE SURFACE...HIGH PRESSURE IS IN CONTROL OF THE FLORIDA
PENINSULA...BUT WILL BE SHIFTING EASTWARD WITH TIME TODAY INTO THE
WESTERN ATLANTIC. SEASONABLY COOL MORNING ONGOING ACROSS THE
REGION WITH TEMPERATURES RANGING FROM FROSTY MIDDLE 30S OVER THE
FAR NORTHERN ZONES TO THE 40S/LOWER 50S ELSEWHERE.
&&
.SHORT TERM (TODAY THROUGH FRIDAY)...
TODAY THROUGH TONIGHT...FAIR...DRY AND SEASONABLE CONDITIONS TO
BE EXPECTED THROUGH THE DAYLIGHT HOURS. STARTING OUT ON THE COLD
SIDE OVER PORTIONS OF THE NATURE COAST...HOWEVER...PLENTY OF SUN
WILL ALLOW TEMPERATURES TO RECOVER QUICKLY THROUGH THE MORNING
HOURS. LOOKING FOR HIGH TEMPS THIS AFTERNOON TO REACH THE UPPER
60S/LOWER 70S NORTH AND LOWER/MID 70S SOUTH UNDER A MIX OF SUN AND
HIGH CLOUDS. LIGHT WINDS BECOME SOUTHEAST THROUGH THE DAY.
EVEN TONIGHT...CONDITIONS ARE EXPECTED TO REMAIN MOSTLY DRY. GOOD
AGREEMENT AMONG THE GUIDANCE MEMBERS THAT THE MAIN SYNOPTIC
FORCING AND SUFFICIENT MOISTENING TO COMMENCE OUR RAIN CHANCES
WILL NOT ARRIVE UNTIL VERY LATE TONIGHT...AND MORE LIKELY AFTER
SUNRISE FRIDAY MORNING. SO...FOR THE OVERNIGHT...EXPECT MOSTLY DRY
CONDITIONS...WITH INCREASING CLOUDS. THE POTENT UPPER LEVEL
DISTURBANCE WILL BE QUICKLY APPROACHING ACROSS THE NORTHERN GULF
COAST WITH ASSOCIATED SURFACE LOW PRESSURE MOVING FROM THE LOWER
MS VALLEY TO THE TN VALLEY. A STRONG COLD FRONT TRAILING SOUTHWARD
FROM THIS LOW WILL BE ALSO QUICKLY TRANSLATING EASTWARD ACROSS THE
GULF OF MEXICO. EXPECT WINDS TO INCREASE OUT OF THE SOUTH AND
SOUTHEAST AHEAD OF THIS FRONT...ESPECIALLY OVER THE COASTAL
WATERS.
FRIDAY...CONDITIONS ARE LIKELY TO GO DOWNHILL QUICKLY FRIDAY
MORNING. GFS/ECMWF BOTH SHOW HEIGHT FALLS COMMENCING...WITH A
BROAD AND IMPRESSIVE SWATH OF DEEP LAYER QVECTOR CONVERGENCE
OVERSPREADING THE REGION BY MIDDAY. THIS BROAD SYNOPTIC FORCING
FOR LIFT WILL LIE UNDERNEATH A HIGHLY DIFFLUENCE FLOW
ALOFT...FURTHER AIDING THE UPWARD MOTION. THEREFORE...EXPECT A
BAND...OR BANDS OF SHOWERS AND EMBEDDED STORMS TO QUICKLY
APPROACH THE FLORIDA WEST COAST FRIDAY MORNING... AND THEN SPREAD
INLAND THROUGH MIDDAY/EARLY AFTERNOON. HAVE GONE WITH CATEGORICAL
RAIN CHANCES FOR ALL ZONES FRIDAY MORNING/EARLY AFTERNOON. THE
PASSAGE OF THE COLD FRONT MIDDAY FRIDAY INTO FRIDAY AFTERNOON
SHOULD END THE ORGANIZED RAIN FROM WEST TO EAST. IF THE GFS IS
CORRECT...THEN MUCH OF THE STEADIER SHOWER CHANCES WILL BE MOVING
EAST OF OUR REGION AFTER 17-19Z. EVEN THOUGH THE PRE-FRONTAL RAIN
WILL BE OVER BY LATE IN THE DAY...CAN NOT COMPLETELY REMOVE RAIN
CHANCES INTO FRIDAY NIGHT (ESPECIALLY CLOSE TO THE COAST) AS
STRONG COLD AIR ADVECTION AND CONTINUED STRONG PVA ALOFT SHOULD BE
ENOUGH TO SUPPORT MORE SCT AND SHALLOW SHOWER ACTIVITY MOVING OFF
THE EASTERN GULF.
THERE IS SOME POTENTIAL FOR A FEW STRONG THUNDERSTORMS FRIDAY
AHEAD OF THIS COLD FRONT...HOWEVER THE THREAT FOR SEVERE WEATHER
WITH THIS SYSTEM APPEARS MUCH GREATER TO THE NORTHWEST OF OUR
REGION...MOSTLY ACROSS THE FLORIDA PANHANDLE. CONDITIONS CERTAINLY
DO NOT APPEAR AS VOLATILE AS THEY WERE WITH THE EVENT THIS PAST
WEEKEND. THE STORM PREDICTION CENTER HAS OUTLOOKED AT THIS
TIME...ONLY LEVY COUNTY IN A MARGINAL RISK FOR SEVERE WEATHER. NO
ZONES FURTHER SOUTH ARE CURRENTLY OUTLOOKED WITH A RISK FOR
ORGANIZED SEVERE WEATHER. HOWEVER...WE CAN NEVER LET OUR GUARD
DOWN. THE WIND FIELDS ARE STILL SUFFICIENT FOR A FEW STRONGER
STORMS...WITH FREQUENT LIGHTNING AND GUSTY WINDS THE MAIN HAZARDS.
FORECASTERS WILL CERTAINLY BE WATCHING/MONITORING THE SITUATION
CLOSELY EARLY FRIDAY AS THE STORMS APPROACH THE COAST.
&&
.LONG TERM (FRIDAY NIGHT - WEDNESDAY)...
THE PERIOD BEGINS WITH AN UPPER TROUGH CENTERED OVER THE TN/AL/GA
BORDER THAT HAS A SURFACE REFLECTION ALONG THE GA/SC
LINE...TRAILING A COLD FRONT SOUTHWARD ACROSS EAST CENTRAL FL AND
SOUTH FL. THESE FEATURES MOVE EAST FRI NIGHT THEN OFFSHORE SAT. AN
UPPER RIDGE MOVES INTO THE MID- CONUS AS SURFACE HIGH PRESSURE
BUILDS OVER THE SOUTHERN PLAINS. THESE AND THE DEPARTING FEATURES
MAINTAIN A TIGHT PRESSURE GRADIENT WITH STRONG WEST AND NORTHWEST
WINDS CREATING MARINE AND COASTAL ISSUES. COLD AIR MOVING ACROSS
THE WARMER GULF WATERS ALONG THE TROUGHINESS DOWN OVER THE GULF
WILL SUPPORT SLIGHT CHANCE TO CHANCE SHOWERS THAT WIND DOWN DURING
SAT.
SUN AND MON - THE UPPER RIDGE AND SURFACE HIGH PRESSURE TRACK EAST...
ACROSS THE GULF COAST AND SOUTHEASTERN STATES TO THE ATLANTIC. A COLD
DRY STABLE AIR MASS SPREADS ACROSS THE AREA WITH NORTHWESTERLY WINDS.
TEMPERATURES WILL BE AT OR NEAR FREEZING FOR THE NATURE COAST EARLY
SUN MORNING WITH POSSIBLE CRITICAL WIND CHILLS DOWN INTO THE
CENTRAL COUNTIES. AS THE HIGH MOVES BY WINDS DIMINISH AND BECOME
MORE NORTHEASTERLY WITH TEMPERATURES MODERATING.
TUE-WED - THE SURFACE HIGH CONTINUE TO MOVE EAST BUT RIDGE BACK TO FL
INITIALLY. AN UPPER TOUGH WITH AN ATTENDANT COLD FRONT SETTLES INTO THE
MISSISSIPPI VALLEY TUE THEN SHIFTS TO THE EASTERN SEABOARD AND NORTHERN
FL WED. THE ATMOSPHERE WARMS AND MOISTENS WHICH WITH THE APPROACHING
FRONT WILL SUPPORT SOME SLIGHT CHANCE SHOWER TUE THAT INCREASE TO
CHANCE BUT OCCASIONALLY LIKELY WED.
&&
.AVIATION...
&&
.MARINE...
HIGH PRESSURE MOVES EASTWARD TODAY ALLOWING WINDS TO SHIFT TO THE
SOUTHEAST. A STRONG COLD FRONT WILL THEN APPROACH THE EASTERN GULF
OF MEXICO OVERNIGHT AND CROSS THE REGION FRIDAY MORNING THROUGH
EARLY AFTERNOON. SOUTHERLY WINDS WILL INCREASE TO AT LEAST
CAUTIONARY LEVELS OVERNIGHT...WITH SOME POTENTIAL FOR ADVISORY
LEVEL WINDS OVER THE OFFSHORE WATERS AFTER MIDNIGHT. WINDS SHIFT
TO THE WEST AND NORTHWEST IN THE WAKE OF THE FRONT LATER FRIDAY
AND RAPIDLY INCREASE TO ADVISORY LEVELS OVER ALL THE FORECAST
WATERS BY FRIDAY EVENING. A PERIOD OF VERY ROUGH AND HAZARDOUS
BOATING CONDITIONS IS EXPECTED OVER THE FORECAST WATERS FRIDAY
NIGHT THROUGH SATURDAY. NORTHWEST WINDS ARE LIKELY TO GUST OVER
GALE FORCE AT TIMES THROUGH SATURDAY MORNING. WINDS WILL SLOWLY
SUBSIDE SATURDAY NIGHT INTO SUNDAY MORNING AS HIGH PRESSURE
BUILDS OVER THE REGION. HOWEVER...RESIDUAL SEAS WILL BE SLOWER TO
DROP BELOW ADVISORY LEVELS...RESULTING IN HEADLINES LIKELY
CONTINUING FOR PORTIONS OF THE WATERS THROUGH SATURDAY NIGHT.
&&
.FIRE WEATHER...
HIGH PRESSURE WILL SHIFT EASTWARD TODAY ALLOWING WINDS TO COME
AROUND TO THE SOUTHEAST. THE SOUTHEAST WIND WILL BEGIN THE
BRINGING A SLOW INCREASE IN MOISTURE TO THE REGION. RELATIVE
HUMIDITY VALUES ARE FORECAST TO BRIEFLY FALL BELOW 35 PERCENT
ACROSS PORTION OF THE NORTHERN NATURE COAST...BUT ELSEWHERE
SHOULD REMAIN GENERALLY ABOVE CRITICAL LEVELS. A COLD FRONT
WILL APPROACH AND CROSS THE REGION DURING THE DAYLIGHT HOURS
OF FRIDAY WITH MOST LOCATIONS RECEIVING A WETTING RAINFALL.
WINDS SHIFT TO THE NORTHWEST BEHIND THE FRONT AND BECOME VERY
GUSTY FRIDAY NIGHT INTO SATURDAY. THESE WINDS WILL ALSO DELIVER
A MUCH COLDER AIRMASS TO THE REGION FOR SATURDAY AND SATURDAY
NIGHT.
FOG POTENTIAL...
PATCHY FOG WILL BE AROUND THE REGION EARLY THIS MORNING. NO
ADDITIONAL FOG CONCERNS ARE ANTICIPATED THROUGH SATURDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 72 58 70 52 / 0 0 90 30
FMY 75 59 73 57 / 0 10 90 20
GIF 73 57 72 50 / 0 0 90 20
SRQ 71 59 70 56 / 0 10 90 30
BKV 73 55 69 48 / 0 0 90 30
SPG 71 59 69 53 / 0 0 90 30
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
SYNOPSIS/SHORT TERM/AVIATION/MARINE/FIRE WX...MROCZKA
LONG TERM/DECISION SUPPORT...RUDE
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
640 AM EST THU JAN 21 2016
.SYNOPSIS...
MOISTURE WILL INCREASE AHEAD OF LOW PRESSURE APPROACHING FROM THE
WEST. THE LOW WILL BE NEAR THE FORECAST AREA FRIDAY INTO FRIDAY
NIGHT AND ALONG THE NORTH CAROLINA AND VIRGINIA COASTS SATURDAY.
DRYING WILL OCCUR SUNDAY AS THE LOW MOVES FARTHER AWAY AND HIGH
PRESSURE APPROACHES FROM THE WEST.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
HIGH PRESSURE WILL BE WEDGED INTO THE FORECAST AREA FROM THE NORTH
WITH A STRENGTHENING WARM FRONT SOUTH OF THE AREA TODAY. THE
MODELS INDICATE LITTLE ISENTROPIC LIFT IN THE NORTH SECTION OF THE
FORECAST AREA...BUT INCREASING LIFT IN THE SOUTH PART. THE NAM
AND GFS KEEP MOISTURE SHALLOW IN THE NORTH PART...BUT IT BECOMES
DEEPER IN THE SOUTH. THE HRRR AND ARW INDICATE SCATTERED AREAS OF
RAIN IN THE SOUTH HALF OF THE AREA. THE NAM AND GFS MOS INDICATE
POPS LESS THAN 20 PERCENT IN THE NORTH TO NEAR 60 PERCENT IN THE
SOUTH. OBSERVATION TRENDS PLUS THE NAM AND GFS KEEP SURFACE WET
BULB TEMPERATURES ABOVE FREEZING IN THE SOUTH PART WHERE WE EXPECT
PRECIPITATION. WE HAVE FORECASTED ALL LIQUID PRECIPITATION TODAY.
THE TEMPERATURE GUIDANCE APPEARS TOO WARM BECAUSE OF THE WEDGE
PATTERN TODAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
THREAT FOR WINTRY PRECIPITATION WITH SIGNIFICANT IMPACTS
INCREASING ACROSS THE NORTHERN MIDLANDS MAINLY FOR FREEZING RAIN
LATE TONIGHT THROUGH FRIDAY. WINTER STORM WARNING IS NOW IN
EFFECT FOR LANCASTER AND CHESTERFIELD COUNTIES. A WINTER WEATHER
ADVISORY FOR FREEING RAIN HAS BEEN ISSUED FOR NEWBERRY...
FAIRFIELD...KERSHAW AND LEE COUNTIES.
SIGNIFICANT DEEPENING OF THE SURFACE LOW OVER THE LOWER MISSISSIPPI
RIVER VALLEY WILL OCCUR IN RESPONSE TO A NEGATIVE TILTING OF THE
UPPER TROUGH AS IT TRANSITIONS INTO A CLOSED LOW OVER MS/AL.
ISENTROPIC LIFT WILL STRENGTHEN OVER THE REGION TONIGHT INTO
FRIDAY AS THE WARM FRONT SLOWLY LIFTS NORTHWARD. CATEGORICAL POPS
STILL IN ORDER.
CONFLUENT 500MB FLOW OVER THE EASTERN OHIO VALLEY AND NORTHEAST
WILL RESULT IN A STRENGTHENING SURFACE RIDGE OVER THE MID ATLANTIC
AND COLD AIR DAMMING WILL DEVELOP ACROSS THE CAROLINAS INTO THE
CSRA TONIGHT INTO FRIDAY. MODELS HAVE BEEN TRENDING COOLER WITH
SURFACE WETBULB TEMPERATURES FALLING BELOW FREEZING ACROSS THE
NORTHERN AND CENTRAL MIDLANDS BY EARLY FRIDAY MORNING. THIS WILL
LIKELY RESULT IN A PERIOD OF FREEZING RAIN. THERE IS STILL SOME
UNCERTAINTY AS TO HOW FAR SOUTH THE FREEZING RAIN WILL DEVELOP.
BASED ON LATEST GUIDANCE WINTER STORM WARNING HAS BEEN POSTED FOR
NORTH MIDLANDS. THERE IS POTENTIAL FOR SIGNIFICANT ICING. WE WILL
CONTINUE TO MONITOR MODEL TRENDS. IF COLD AIR DAMMING IS STRONGER...
SIGNIFICANT ICING MAY DEVELOP FURTHER SOUTH.
TEMPERATURES TONIGHT ARE EXPECTED TO RANGE FROM AROUND 30 NORTH
MIDLANDS TO AROUND 40 ACROSS THE CSRA AND SOUTHEAST MIDLANDS.
SHOULD SEE LITTLE CHANGE IN TEMPERATURES ON FRIDAY ACROSS THE
NORTH MIDLANDS AS STRONG WEDGE CONDITIONS HOLD. TEMPERATURES WARM
ABOVE FREEZING ON FRIDAY ACROSS THE CENTRAL AND SOUTHERN MIDLANDS
AS WELL AS THE CSRA.
SIGNIFICANT QPF IS FORECAST WITH LIQUID ACCUMULATIONS OF 0.75-1.50
INCHES.
FRIDAY NIGHT AND SATURDAY...SURFACE LOW DEEPENS AND MOVES UP THE
COAST TO NEAR NORFOLK BY 12Z SATURDAY WHILE THE CLOSED UPPER LOW
SLOWLY MOVES OVER THE SOUTHERN APPALACHIANS BY SATURDAY MORNING. MID
LEVEL DRY SLOT FORECAST TO MOVE OVER THE FORECAST AREA FRIDAY NIGHT
INTO EARLY SATURDAY WHICH WILL RESULT IN MUCH LOWER POPS FRIDAY
NIGHT.
THE UPPER LOW WILL DRIFT EAST ACROSS THE CAROLINAS ON SATURDAY WITH
THE CORE OF THE COLD AIR ALOFT MOVING OVER THE FORECAST AREA WITH
500MB TEMPS AS COLD AS -26C TO -27C. 00Z NAM AND GFS SHOW DEEPER
MOISTURE INTO SNOW GROWTH ZONE. WILL GO WITH SNOW SHOWERS ACROSS
MUCH OF THE MIDLANDS AND CSRA SATURDAY MORNING. ACCUMULATION MORE
LIKELY NORTH...SOME LIGHT ACCUMULATION IN THE CENTRAL AND
PIEDMONT.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
SURFACE HIGH PRESSURE AND DRIER AIR WILL RETURN TO THE REGION FOR
SUNDAY AND MONDAY. MODELS ALSO INDICATE UPPER LEVEL RIDGING WITH
MODERATING TEMPERATURES. THE UPPER RIDGE WILL MOVE OFF THE COAST
TUESDAY WITH THE NEXT COLD FRONT MOVING INTO THE AREA. THERE
APPEARS TO BE SLIGHT TIMING DIFFERENCES BETWEEN THE GFS AND ECMWF
WITH THE FRONTAL PASSAGE...ALTHOUGH BOTH MODELS PUSH THE FRONT
OFF THE COAST BY LATE WEDNESDAY WITH BELOW NORMAL TEMPERATURES TO
FOLLOW. HAVE INDICATED A CHANCE OF SHOWERS MONDAY NIGHT INTO
WEDNESDAY.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
THE MODELS INDICATE INCREASING ISENTROPIC LIFT AND MOISTURE
SPREADING INTO THE FORECAST AREA FROM SOUTHWEST TO NORTHEAST AHEAD
OF APPROACHING LOW PRESSURE. WE USED THE GFS LAMP FOR THE TIMING
OF CONDITIONS LOWERING INTO THE MVFR AND IFR CATEGORIES. THE
MODELS WERE CONSISTENT KEEPING SURFACE WET BULB TEMPERATURES ABOVE
FREEZING AND WE HAVE INDICATED ALL LIQUID PRECIPITATION DURING THE
TAF PERIOD. USED THE GFS LAMP FOR THE WIND FORECAST. EXPECT MAINLY
EAST WINDS 5 TO 10 KNOTS.
EXTENDED AVIATION OUTLOOK....PRECIPITATION AND WIDESPREAD IFR TO
MVFR CONDITIONS EXPECTED THROUGH SATURDAY. WINTRY PRECIPITATION IS
POSSIBLE SATURDAY. BREEZY CONDITIONS POSSIBLE SATURDAY AND
SATURDAY NIGHT.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...WINTER STORM WARNING FROM 1 AM FRIDAY TO 7 PM EST SATURDAY FOR
SCZ015-016.
FREEZING RAIN ADVISORY FROM 1 AM TO NOON EST FRIDAY FOR
SCZ020>022-029.
&&
$$
SYNOPSIS...99
NEAR TERM...99
SHORT TERM...99
LONG TERM...99
AVIATION...99
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
523 AM EST THU JAN 21 2016
.SYNOPSIS...
MOISTURE WILL INCREASE AHEAD OF LOW PRESSURE APPROACHING FROM THE
WEST. THE LOW WILL BE NEAR THE FORECAST AREA FRIDAY INTO FRIDAY
NIGHT AND ALONG THE NORTH CAROLINA AND VIRGINIA COASTS SATURDAY.
DRYING WILL OCCUR SUNDAY AS THE LOW MOVES FARTHER AWAY AND HIGH
PRESSURE APPROACHES FROM THE WEST.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
HIGH PRESSURE WILL BE WEDGED INTO THE FORECAST AREA FROM THE NORTH
WITH A STRENGTHENING WARM FRONT SOUTH OF THE AREA TODAY. THE
MODELS INDICATE LITTLE ISENTROPIC LIFT IN THE NORTH SECTION OF THE
FORECAST AREA...BUT INCREASING LIFT IN THE SOUTH PART. THE NAM
AND GFS KEEP MOISTURE SHALLOW IN THE NORTH PART...BUT IT BECOMES
DEEPER IN THE SOUTH. THE HRRR AND ARW INDICATE SCATTERED AREAS OF
RAIN IN THE SOUTH HALF OF THE AREA. THE NAM AND GFS MOS INDICATE
POPS LESS THAN 20 PERCENT IN THE NORTH TO NEAR 60 PERCENT IN THE
SOUTH. OBSERVATION TRENDS PLUS THE NAM AND GFS KEEP SURFACE WET
BULB TEMPERATURES ABOVE FREEZING IN THE SOUTH PART WHERE WE EXPECT
PRECIPITATION. WE HAVE FORECASTED ALL LIQUID PRECIPITATION TODAY.
THE TEMPERATURE GUIDANCE APPEARS TOO WARM BECAUSE OF THE WEDGE
PATTERN TODAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
THREAT FOR WINTRY PRECIPITATION WITH SIGNIFICANT IMPACTS
INCREASING ACROSS THE NORTHERN MIDLANDS MAINLY FOR FREEZING RAIN
LATE TONIGHT THROUGH FRIDAY. WINTER STORM WARNING IS NOW IN
EFFECT FOR LANCASTER AND CHESTERFIELD COUNTIES. A WINTER WEATHER
ADVISORY FOR FREEING RAIN HAS BEEN ISSUED FOR NEWBERRY...
FAIRFIELD...KERSHAW AND LEE COUNTIES.
SIGNIFICANT DEEPENING OF THE SURFACE LOW OVER THE LOWER MISSISSIPPI
RIVER VALLEY WILL OCCUR IN RESPONSE TO A NEGATIVE TILTING OF THE
UPPER TROUGH AS IT TRANSITIONS INTO A CLOSED LOW OVER MS/AL.
ISENTROPIC LIFT WILL STRENGTHEN OVER THE REGION TONIGHT INTO
FRIDAY AS THE WARM FRONT SLOWLY LIFTS NORTHWARD. CATEGORICAL POPS
STILL IN ORDER.
CONFLUENT 500MB FLOW OVER THE EASTERN OHIO VALLEY AND NORTHEAST
WILL RESULT IN A STRENGTHENING SURFACE RIDGE OVER THE MID ATLANTIC
AND COLD AIR DAMMING WILL DEVELOP ACROSS THE CAROLINAS INTO THE
CSRA TONIGHT INTO FRIDAY. MODELS HAVE BEEN TRENDING COOLER WITH
SURFACE WETBULB TEMPERATURES FALLING BELOW FREEZING ACROSS THE
NORTHERN AND CENTRAL MIDLANDS BY EARLY FRIDAY MORNING. THIS WILL
LIKELY RESULT IN A PERIOD OF FREEZING RAIN. THERE IS STILL SOME
UNCERTAINTY AS TO HOW FAR SOUTH THE FREEZING RAIN WILL DEVELOP.
BASED ON LATEST GUIDANCE WINTER STORM WARNING HAS BEEN POSTED FOR
NORTH MIDLANDS. THERE IS POTENTIAL FOR SIGNIFICANT ICING. WE WILL
CONTINUE TO MONITOR MODEL TRENDS. IF COLD AIR DAMMING IS STRONGER...
SIGNIFICANT ICING MAY DEVELOP FURTHER SOUTH.
TEMPERATURES TONIGHT ARE EXPECTED TO RANGE FROM AROUND 30 NORTH
MIDLANDS TO AROUND 40 ACROSS THE CSRA AND SOUTHEAST MIDLANDS.
SHOULD SEE LITTLE CHANGE IN TEMPERATURES ON FRIDAY ACROSS THE
NORTH MIDLANDS AS STRONG WEDGE CONDITIONS HOLD. TEMPERATURES WARM
ABOVE FREEZING ON FRIDAY ACROSS THE CENTRAL AND SOUTHERN MIDLANDS
AS WELL AS THE CSRA.
SIGNIFICANT QPF IS FORECAST WITH LIQUID ACCUMULATIONS OF 0.75-1.50
INCHES.
FRIDAY NIGHT AND SATURDAY...SURFACE LOW DEEPENS AND MOVES UP THE
COAST TO NEAR NORFOLK BY 12Z SATURDAY WHILE THE CLOSED UPPER LOW
SLOWLY MOVES OVER THE SOUTHERN APPALACHIANS BY SATURDAY MORNING. MID
LEVEL DRY SLOT FORECAST TO MOVE OVER THE FORECAST AREA FRIDAY NIGHT
INTO EARLY SATURDAY WHICH WILL RESULT IN MUCH LOWER POPS FRIDAY
NIGHT.
THE UPPER LOW WILL DRIFT EAST ACROSS THE CAROLINAS ON SATURDAY WITH
THE CORE OF THE COLD AIR ALOFT MOVING OVER THE FORECAST AREA WITH
500MB TEMPS AS COLD AS -26C TO -27C. 00Z NAM AND GFS SHOW DEEPER
MOISTURE INTO SNOW GROWTH ZONE. WILL GO WITH SNOW SHOWERS ACROSS
MUCH OF THE MIDLANDS AND CSRA SATURDAY MORNING. ACCUMULATION MORE
LIKELY NORTH...SOME LIGHT ACCUMULATION IN THE CENTRAL AND
PIEDMONT.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
SURFACE HIGH PRESSURE AND DRIER AIR WILL RETURN TO THE REGION FOR
SUNDAY AND MONDAY. MODELS ALSO INDICATE UPPER LEVEL RIDGING WITH
MODERATING TEMPERATURES. THE UPPER RIDGE WILL MOVE OFF THE COAST
TUESDAY WITH THE NEXT COLD FRONT MOVING INTO THE AREA. THERE
APPEARS TO BE SLIGHT TIMING DIFFERENCES BETWEEN THE GFS AND ECMWF
WITH THE FRONTAL PASSAGE...ALTHOUGH BOTH MODELS PUSH THE FRONT
OFF THE COAST BY LATE WEDNESDAY WITH BELOW NORMAL TEMPERATURES TO
FOLLOW. HAVE INDICATED A CHANCE OF SHOWERS MONDAY NIGHT INTO
WEDNESDAY.
&&
.AVIATION /09Z THURSDAY THROUGH MONDAY/...
VFR CEILINGS WERE OCCURRING AT TAF ISSUANCE TIME ASSOCIATED WITH
HIGH PRESSURE WEDGING INTO THE AREA FROM THE NORTH AND A WARM
FRONT JUST TO THE SOUTH. THE MODELS INDICATE INCREASING ISENTROPIC
LIFT AND MOISTURE MAINLY IN THE SOUTH PART AFFECTING AGS AND DNL
TODAY. THE DEEPER MOISTURE SHOULD SPREAD FARTHER NORTH AFTER 00Z.
THE NAM MOS AND SREF GUIDANCE WERE FASTER LOWERING CEILINGS
COMPARED TO THE GFS MOS. BASED ON OBSERVATION TRENDS WE LEANED
TOWARD THE NAM AT AGS AND DNL...AND USED AN AVERAGE OF THE
GUIDANCE AT CAE...CUB...AND OGB. THE MODELS WERE CONSISTENT
KEEPING SURFACE WET BULB TEMPERATURES ABOVE FREEZING AND WE HAVE
INDICATED ALL LIQUID PRECIPITATION DURING THE TAF PERIOD. USED THE
GFS LAMP FOR THE WIND FORECAST. EXPECT MAINLY EAST WINDS NEAR 5
KNOTS.
EXTENDED AVIATION OUTLOOK....PRECIPITATION AND WIDESPREAD IFR TO
MVFR CONDITIONS EXPECTED THROUGH SATURDAY. WINTRY PRECIPITATION IS
POSSIBLE SATURDAY. BREEZY CONDITIONS POSSIBLE SATURDAY AND
SATURDAY NIGHT.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...WINTER STORM WARNING FROM 1 AM FRIDAY TO 7 PM EST SATURDAY FOR
SCZ015-016.
FREEZING RAIN ADVISORY FROM 1 AM TO NOON EST FRIDAY FOR
SCZ020>022-029.
&&
$$
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
624 AM CST THU JAN 21 2016
.SHORT TERM: (Through Late This Afternoon)
Issued at 403 AM CST Thu Jan 21 2016
Vort max which is showing up nicely on water vapor near the MO/AR
border as of 1000 UTC and is moving northeasward toward central
Missouri. The 0000 UTC models failed to capture this vort and
associated precipitation but the recent runs of the HRRR and RAP have.
The HRRR/RAP does weaken this area of precipitation with
time...but each successive run of the each model weaken it a bit
later than the previous run. Have upped PoPs into the likely
category for far western CWA due to the nice signature on WV
imagery. Best chance for this snow activity will be across
Boone/Moniteau/Osage counties. Amounts should be light (under half
an inch). This area will need to be monitored through the morning
hours and further updates may be necessary if the precipitation
shield maintains its strength over the next several hours.
Portions of southeast Missouri may also need PoPs adjusted upward
if this does occur.
Otherwise...expect a cloudy day with highs several degrees below
normal for mid/late January.
Gosselin
.LONG TERM: (Tonight through Wednesday)
Issued at 403 AM CST Thu Jan 21 2016
(Tonight- Wednesday)
Main system begins to develop and deepen beginning tonight across
the lower Mississippi Valley. Still appears even our far southern
CWA will be too far north to receive any signigicant snow
accumulations. Though cannot totally rule out some light snow on
northern periphery of this system across portions of southeastern
Missouri and southwest Illinois either tonight or on Friday due to
some weak WAA and UL divergence associated with RER of jet streak
aloft.
System will continue to deepen and move off to the east-northeast
away from the area leaving light northerly sfc winds in its wake.
Surface ridge moves into the area on Saturday with seasonable
temperatures continuing.
By Sunday...return flow around aforementioned high and rapidly
rising heights aloft signal a quick warmup ahead of the next system.
High temperature forecast will be tricky/complicated by amount of
mid/high level cloudiness and remaining snow cover. Continued to
lean warm for most areas...but particularly so for areas with little
existing snowcover.
Next system to affect the mid-Mississippi Valley continues to look
like mainly a light rain/snow situation as the sfc low tracks across
roughly the middle of the CWA and transverses the area fairly
quickly. Temperatures out ahead of the system on Monday look to be
above normal before falling back to near normal behind the system on
Tuesday and Wendesday.
Gosselin
&&
.AVIATION: (For the 12z TAFs through 12z Friday Morning)
Issued at 619 AM CST Thu Jan 21 2016
Upper level system over eastern Kansas spreading mid and high
clouds across forecast area. Could see some MVFR cigs/vsbys at
KCOU as light snow moves north into central MO this morning, then
diminish by early this afternoon. Otherwise, east winds to
continue backing to the northeast, then north through the forecast
period as the surface low tracks to our south and southeast.
Specifics for KSTL:
Upper level system over eastern Kansas spreading mid and high
clouds across forecast area. Could see some scattered mvfr clouds
through forecast period. Otherwise, east winds to continue
backing to the northeast by 04z Friday, then north by 12z Friday
at KSTL as the surface low tracks to our south and southeast.
Byrd
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
411 AM CST THU JAN 21 2016
.SHORT TERM: (Through Late This Afternoon)
Issued at 403 AM CST Thu Jan 21 2016
Vort max which is showing up nicely on water vapor near the MO/AR
border as of 1000 UTC and is moving northeasward toward central
Missouri. The 0000 UTC models failed to capture this vort and
associated precipitation but the recent runs of the HRRR and RAP have.
The HRRR/RAP does weaken this area of precipitation with
time...but each successive run of the each model weaken it a bit
later than the previous run. Have upped PoPs into the likely
category for far western CWA due to the nice signature on WV
imagery. Best chance for this snow activity will be across
Boone/Moniteau/Osage counties. Amounts should be light (under half
an inch). This area will need to be monitored through the morning
hours and further updates may be necessary if the precipitation
shield maintains its strength over the next several hours.
Portions of southeast Missouri may also need PoPs adjusted upward
if this does occur.
Otherwise...expect a cloudy day with highs several degrees below
normal for mid/late January.
Gosselin
.LONG TERM: (Tonight through Wednesday)
Issued at 403 AM CST Thu Jan 21 2016
(Tonight- Wednesday)
Main system begins to develop and deepen beginning tonight across
the lower Mississippi Valley. Still appears even our far southern
CWA will be too far north to receive any signigicant snow
accumulations. Though cannot totally rule out some light snow on
northern periphery of this system across portions of southeastern
Missouri and southwest Illinois either tonight or on Friday due to
some weak WAA and UL divergence associated with RER of jet streak
aloft.
System will continue to deepen and move off to the east-northeast
away from the area leaving light northerly sfc winds in its wake.
Surface ridge moves into the area on Saturday with seasonable
temperatures continuing.
By Sunday...return flow around aforementioned high and rapidly
rising heights aloft signal a quick warmup ahead of the next system.
High temperature forecast will be tricky/complicated by amount of
mid/high level cloudiness and remaining snow cover. Continued to
lean warm for most areas...but particularly so for areas with little
existing snowcover.
Next system to affect the mid-Mississippi Valley continues to look
like mainly a light rain/snow situation as the sfc low tracks across
roughly the middle of the CWA and transverses the area fairly
quickly. Temperatures out ahead of the system on Monday look to be
above normal before falling back to near normal behind the system on
Tuesday and Wendesday.
Gosselin
&&
.AVIATION: (For the 06z TAFs through 06z Thursday Night)
Issued at 1127 PM CST Wed Jan 20 2016
The expected trends of the stratus have not materialized this
evening. Instead the low level flow across IL into the OH Valley
has maintained a northerly component which has kept the stratus
pushing south. This has raised serious doubts whether it can
advect back into the region overnight into Thursday morning after
the flow finally veers to southeasterly. Most of the guidance
suggests NOT, so I am being optomistic keeping flight conditions
predominately VFR dominated by mid-high clouds, with some light
fog potential at KUIN. Still also a remote chance for some spotty
very light snow across parts of central MO but the probability is
very low and most likely not much more than flurries.
Specifics for KSTL:
The expected trends of the stratus have not materialized this
evening and I have serious doubts whether we will see any.Most of
the guidance suggests NOT, so I am being optomistic keeping
flight conditions predominately VFR dominated by mid-high clouds.
Glass
&&
.PRELIMINARY POINT TEMPS/POPS:
Saint Louis 31 22 30 23 / 10 10 10 5
Quincy 27 16 27 15 / 5 5 10 5
Columbia 30 19 29 17 / 50 10 10 5
Jefferson City 30 20 30 18 / 60 10 10 5
Salem 31 21 30 21 / 5 10 10 5
Farmington 30 23 30 21 / 20 20 10 10
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
315 PM EST THU JAN 21 2016
.SYNOPSIS...
MOISTURE WILL INCREASE AHEAD OF LOW PRESSURE APPROACHING FROM THE
WEST. THE LOW WILL BE NEAR THE FORECAST AREA FRIDAY INTO FRIDAY
NIGHT AND ALONG THE NORTH CAROLINA AND VIRGINIA COASTS SATURDAY.
DRYING WILL OCCUR SUNDAY AS THE LOW MOVES FARTHER AWAY AND HIGH
PRESSURE APPROACHES FROM THE WEST.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
LOW PRESSURE OVER THE NORTHWESTERN GULF WILL DEEPEN AND SHIFT
NORTHEASTWARD THROUGH THIS AFTERNOON AND EVENING. CURRENT RADAR
LOOP SHOWS LIGHT RAIN BEGINNING TO MOVE INTO THE SOUTHEASTERN CSRA
THIS AFTERNOON. HAVE LOWERED POPS THROUGH LATE THIS AFTERNOON
BASED ON THE HRRR WHICH APPEARS TO HAVE A GOOD HANDLE ON THE
PRECIP CURRENTLY. STILL EXPECT POPS TO RAMP UP THIS EVENING AS
ISENTROPIC LIFT INCREASES. HAVE FORECASTED ALL LIQUID PRECIPITATION
THROUGH THIS EVENING AS SURFACE WET BULB TEMPERATURES REMAIN ABOVE
FREEZING. CLOUDS HAVE SCATTERED OUT SOME IN THE NORTHERN MIDLANDS
AND CSRA WITH TEMPERATURES RISING A FEW DEGREES HIGHER THAN
PREVIOUSLY FORECAST. HAVE ADJUSTED TEMPERATURES SLIGHTLY BASED ON
TRENDS WITH HIGHS IN THE UPPER 40S TO LOW 50S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
DEEPENING LOW PRESSURE ALONG THE GULF WILL LIFT NORTHEASTWARD INTO
THE TENNESSEE VALLEY OVERNIGHT THROUGH FRIDAY BEFORE TRANSITIONING
TO A DEVELOPING COASTAL LOW FRIDAY EVENING...WHICH WILL THEN LIFT
NORTHWARD OFF THE MID ATLANTIC COAST THROUGH SATURDAY. CLOSED
UPPER LOW WILL MOVE NORTHEASTWARD TOWARDS THE AREA FRIDAY AND THEN
CROSS THE FORECAST AREA FRIDAY NIGHT AND SATURDAY. CONFLUENT 500MB
FLOW ACROSS THE NORTHEAST WILL RESULT IN A BUILDING SURFACE RIDGE
AND COLD AIR DAMMING SCENARIO EAST OF THE APPALACHIANS BEGINNING
LATER TONIGHT AND STRENGTHENING ON FRIDAY AS WIDESPREAD
PRECIPITATION OVERSPREADS THE REGION.
SHOWERS ALREADY DEVELOPING ALONG THE GULF COAST IN VICINITY OF A
DEVELOPING WARM FRONT AND WILL SHIFT NORTHEASTWARD ASSOCIATED WITH
INCREASING ISENTROPIC LIFT AND STRENGTHENING 850MB SOUTHERLY
MOISTURE TRANSPORT. INCREASING POPS THROUGH THE NIGHT TONIGHT TO
CATEGORICAL AFTER 06Z FROM WEST TO EAST. ALL PRECIPITATION IS
EXPECTED TO BE IN THE FORM OF RAIN THROUGH MUCH OF THE NIGHT BUT
INCREASING COOL/DRY NORTHEASTERLY FLOW INTO THE FORECAST AREA
ASSOCIATED WITH COLD AIR DAMMING WILL ALLOW TEMPERATURES TO FALL
ACROSS THE NORTHERN MIDLANDS AND PRECIPITATION WILL TRANSITION TO
FREEZING RAIN AROUND 12Z. 12Z GUIDANCE FROM THE NAM/CANADIAN/EC
CONTINUE TO SHOW COOLER SURFACE WETBULB TEMPS COMPARED TO THE GFS
AND WERE PREFERRED. PRECIPITATION INCREASES THROUGH THE DAY
FRIDAY AS UPPER LEVEL FORCING INCREASES AHEAD OF THE APPROACHING
UPPER LOW AND MOISTURE TRANSPORT IS MAXIMIZED ON A 50 KNOT LOW
LEVEL JET. THE 32 DEGREE SURFACE WETBULB LINE IS EXPECTED TO SHIFT
SOUTHWARD DURING THE MORNING TO EARLY AFTERNOON HOURS FRIDAY
DURING PERIOD OF STEADY PRECIPITATION AND THIS IS THE PERIOD THAT
ICE ACCUMULATION SHOULD BE HIGHEST.
NO CHANGES AT THIS TIME TO THE CURRENT WARNINGS/ADVISORIES AS
CONFIDENCE IS HIGH FOR SIGNIFICANT ICING TO OCCUR ACROSS FAR
NORTHERN MIDLANDS WITH A GRADIENT TO LESS ICE ACCUMULATION MOVING
SOUTHWARD. THERE IS UNCERTAINTY IN HOW FAR SOUTH THE SHALLOW COLD
LAYER WILL MAKE IT AND HOW FAR NORTH THE WARM ADVECTION WILL PUSH
AS THE SURFACE LOW APPROACHES AND TRANSITIONS TO THE COASTAL LOW.
THINK FREEZING RAIN IS POSSIBLE IN COUNTIES SOUTH OF THE ADVISORY
AREA INCLUDING COLUMBIA METRO AND SUMTER AREAS BUT WITH GROUND
TEMPS RELATIVELY WARM AND UNCERTAINTY IN THE EVOLUTION OF THE LOW
LEVEL THERMAL PROFILES THIS FAR SOUTH THINK ANY ICE ACCUMULATION
WILL BE NEGLIBLE AT THIS TIME AND LIKELY TO OCCUR ON TREES AND
ELEVATED SURFACES WITH LITTLE IMPACT ON ROADS. AGAIN...THIS COULD
CHANGE WITH NEW MODEL INFORMATION AND OBSERVATIONS LATER TONIGHT.
THE CHANCE FOR CONVECTION CANNOT BE RULED OUT BUT THINKING THE
WEDGE WILL HOLD STRONG OVER THE FORECAST AREA AND KEEP ANY
CONVECTION SOUTH OF OUR AREA ALONG THE WEDGE BOUNDARY.
TEMPERATURES TONIGHT WILL BE IMPACTED BY WIDESPREAD CLOUD COVER
AND SHOULD SEE LOWS IN THE 40S ACROSS THE SOUTHERN PART OF THE
AREA WHILE THE NORTHERN AND CENTRAL MIDLANDS WILL BE COOLER DUE TO
DIABATIC COOLING EFFECTS AND THE COLD ADVECTION FROM THE
NORTHEASTERLY FLOW DESPITE CLOUD COVER. TEMPERATURES ON SATURDAY
WILL BE NEARLY STEADY BUT MAY SLOWLY FALL ACROSS THE NORTH EARLY
WITH HIGHS RANGING FROM THE LOWER 30S NORTH TO LOWER 40S SOUTH.
POPS DECREASE ACROSS THE REGION FRIDAY EVENING AS PVA AND STRONG
LOW LEVEL MOISTURE TRANSPORT SHIFT EAST OF THE FORECAST AREA AS
THE COASTAL LOW BECOMES THE DOMINANT LOW PRESSURE SYSTEM AND
DEEPENS...LIFTING NORTHEAST AWAY FROM THE AREA. AS THE UPPER LOW
BEGINS TO SHIFT EASTWARD OVER THE FORECAST AREA LATE FRIDAY NIGHT
INTO SATURDAY MORNING EXPECT LIGHT PRECIPITATION TO MOVE BACK OVER
THE REGION AND FORECAST SOUNDINGS SUPPORT SNOW IN THE
WARNING/ADVISORY AREA ALTHOUGH QPF IS EXPECTED TO BE LIGHT WITH
ACCUMULATIONS LESS THAN AN INCH. THE REMAINDER OF THE FORECAST
AREA COULD SEE SOME SNOW OR RAIN/SNOW MIX BUT NO ACCUMULATION IS
EXPECTED.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
UPPER LEVEL RIDGING AND SURFACE HIGH PRESSURE WILL RETURN FOR
SUNDAY AND MONDAY. DRY WEATHER AND MOSTLY SUNNY SKIES EXPECTED.
AN UPPER LEVEL TROUGH WILL LIFT OUT OF THE MIDWEST INTO THE
NORTHEAST EARLY NEXT WEEK AS SURFACE HIGH PRESSURE MOVES OFF THE
COAST. THE ASSOCIATED COLD FRONT WILL SLOWLY APPROACH THE
SOUTHEAST. THE GFS AND ECMWF HAVE COME INTO BETTER AGREEMENT WITH
THE TIMING OF THE FRONTAL PASSAGE. THERE WILL BE A CHANCE FOR
SHOWERS TUESDAY NIGHT INTO WEDNESDAY BEFORE THE FRONT SHIFTS EAST
OF THE CWA WEDNESDAY NIGHT.
&&
.AVIATION /20Z THURSDAY THROUGH TUESDAY/...
VFR/MVFR CONDITIONS EARLY THIS AFTERNOON ARE EXPECTED TO
DETERIORATE TO IFR TONIGHT AND REMAIN IFR THROUGH THE PERIOD.
CEILINGS HAVE FLUCTUATED BETWEEN VFR AND MVFR OVER THE PAST COUPLE
OF HOURS BUT EXPECT MVFR CLOUDS TO OVERSPREAD THE AREA LATE THIS
AFTERNOON AND EVENING AND THEN LOWER TO IFR TONIGHT. THE CHANCE
OF RAIN INCREASES LATE THIS AFTERNOON AND EVENING FROM SOUTHWEST
TO NORTHEAST WITH LIKELY RAIN OVERNIGHT AND INTO FRIDAY. THE
MODELS WERE CONSISTENT KEEPING SURFACE WET BULB TEMPERATURES ABOVE
FREEZING AND WE HAVE INDICATED ALL LIQUID PRECIPITATION AT THE TAF
SITES DURING THE TAF PERIOD. EXPECT MAINLY EAST WINDS 5 TO 10
KNOTS THROUGH THIS AFTERNOON. WINDS OVERNIGHT AND INTO FRIDAY WILL
BE AROUND 10 TO 12 KNOTS WITH GUSTS AROUND 15 KNOTS.
EXTENDED AVIATION OUTLOOK....PRECIPITATION AND WIDESPREAD IFR TO
MVFR CONDITIONS EXPECTED THROUGH SATURDAY. WINTRY PRECIPITATION IS
POSSIBLE SATURDAY. BREEZY CONDITIONS POSSIBLE SATURDAY AND
SATURDAY NIGHT.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...WINTER STORM WARNING FROM 1 AM FRIDAY TO 7 PM EST SATURDAY FOR
SCZ015-016.
FREEZING RAIN ADVISORY FROM 1 AM TO NOON EST FRIDAY FOR
SCZ020>022-029.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
213 PM EST THU JAN 21 2016
.SYNOPSIS...
MOISTURE WILL INCREASE AHEAD OF LOW PRESSURE APPROACHING FROM THE
WEST. THE LOW WILL BE NEAR THE FORECAST AREA FRIDAY INTO FRIDAY
NIGHT AND ALONG THE NORTH CAROLINA AND VIRGINIA COASTS SATURDAY.
DRYING WILL OCCUR SUNDAY AS THE LOW MOVES FARTHER AWAY AND HIGH
PRESSURE APPROACHES FROM THE WEST.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
LOW PRESSURE OVER THE NORTHWESTERN GULF WILL DEEPEN AND SHIFT
NORTHEASTWARD THROUGH THIS AFTERNOON AND EVENING. CURRENT RADAR
LOOP SHOWS LIGHT RAIN BEGINNING TO MOVE INTO THE SOUTHEASTERN CSRA
THIS AFTERNOON. HAVE LOWERED POPS THROUGH LATE THIS AFTERNOON
BASED ON THE HRRR WHICH APPEARS TO HAVE A GOOD HANDLE ON THE
PRECIP CURRENTLY. STILL EXPECT POPS TO RAMP UP THIS EVENING AS
ISENTROPIC LIFT INCREASES. HAVE FORECASTED ALL LIQUID PRECIPITATION
THROUGH THIS EVENING AS SURFACE WET BULB TEMPERATURES REMAIN ABOVE
FREEZING. CLOUDS HAVE SCATTERED OUT SOME IN THE NORTHERN MIDLANDS
AND CSRA WITH TEMPERATURES RISING A FEW DEGREES HIGHER THAN
PREVIOUSLY FORECAST. HAVE ADJUSTED TEMPERATURES SLIGHTLY BASED ON
TRENDS WITH HIGHS IN THE UPPER 40S TO LOW 50S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
THREAT FOR WINTRY PRECIPITATION WITH SIGNIFICANT IMPACTS
INCREASING ACROSS THE NORTHERN MIDLANDS MAINLY FOR FREEZING RAIN
LATE TONIGHT THROUGH FRIDAY. WINTER STORM WARNING IS NOW IN
EFFECT FOR LANCASTER AND CHESTERFIELD COUNTIES. A WINTER WEATHER
ADVISORY FOR FREEING RAIN HAS BEEN ISSUED FOR NEWBERRY...
FAIRFIELD...KERSHAW AND LEE COUNTIES.
SIGNIFICANT DEEPENING OF THE SURFACE LOW OVER THE LOWER MISSISSIPPI
RIVER VALLEY WILL OCCUR IN RESPONSE TO A NEGATIVE TILTING OF THE
UPPER TROUGH AS IT TRANSITIONS INTO A CLOSED LOW OVER MS/AL.
ISENTROPIC LIFT WILL STRENGTHEN OVER THE REGION TONIGHT INTO
FRIDAY AS THE WARM FRONT SLOWLY LIFTS NORTHWARD. CATEGORICAL POPS
STILL IN ORDER.
CONFLUENT 500MB FLOW OVER THE EASTERN OHIO VALLEY AND NORTHEAST
WILL RESULT IN A STRENGTHENING SURFACE RIDGE OVER THE MID ATLANTIC
AND COLD AIR DAMMING WILL DEVELOP ACROSS THE CAROLINAS INTO THE
CSRA TONIGHT INTO FRIDAY. MODELS HAVE BEEN TRENDING COOLER WITH
SURFACE WETBULB TEMPERATURES FALLING BELOW FREEZING ACROSS THE
NORTHERN AND CENTRAL MIDLANDS BY EARLY FRIDAY MORNING. THIS WILL
LIKELY RESULT IN A PERIOD OF FREEZING RAIN. THERE IS STILL SOME
UNCERTAINTY AS TO HOW FAR SOUTH THE FREEZING RAIN WILL DEVELOP.
BASED ON LATEST GUIDANCE WINTER STORM WARNING HAS BEEN POSTED FOR
NORTH MIDLANDS. THERE IS POTENTIAL FOR SIGNIFICANT ICING. WE WILL
CONTINUE TO MONITOR MODEL TRENDS. IF COLD AIR DAMMING IS STRONGER...
SIGNIFICANT ICING MAY DEVELOP FURTHER SOUTH.
TEMPERATURES TONIGHT ARE EXPECTED TO RANGE FROM AROUND 30 NORTH
MIDLANDS TO AROUND 40 ACROSS THE CSRA AND SOUTHEAST MIDLANDS.
SHOULD SEE LITTLE CHANGE IN TEMPERATURES ON FRIDAY ACROSS THE
NORTH MIDLANDS AS STRONG WEDGE CONDITIONS HOLD. TEMPERATURES WARM
ABOVE FREEZING ON FRIDAY ACROSS THE CENTRAL AND SOUTHERN MIDLANDS
AS WELL AS THE CSRA.
SIGNIFICANT QPF IS FORECAST WITH LIQUID ACCUMULATIONS OF 0.75-1.50
INCHES.
FRIDAY NIGHT AND SATURDAY...SURFACE LOW DEEPENS AND MOVES UP THE
COAST TO NEAR NORFOLK BY 12Z SATURDAY WHILE THE CLOSED UPPER LOW
SLOWLY MOVES OVER THE SOUTHERN APPALACHIANS BY SATURDAY MORNING. MID
LEVEL DRY SLOT FORECAST TO MOVE OVER THE FORECAST AREA FRIDAY NIGHT
INTO EARLY SATURDAY WHICH WILL RESULT IN MUCH LOWER POPS FRIDAY
NIGHT.
THE UPPER LOW WILL DRIFT EAST ACROSS THE CAROLINAS ON SATURDAY WITH
THE CORE OF THE COLD AIR ALOFT MOVING OVER THE FORECAST AREA WITH
500MB TEMPS AS COLD AS -26C TO -27C. 00Z NAM AND GFS SHOW DEEPER
MOISTURE INTO SNOW GROWTH ZONE. WILL GO WITH SNOW SHOWERS ACROSS
MUCH OF THE MIDLANDS AND CSRA SATURDAY MORNING. ACCUMULATION MORE
LIKELY NORTH...SOME LIGHT ACCUMULATION IN THE CENTRAL AND
PIEDMONT.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
UPPER LEVEL RIDGING AND SURFACE HIGH PRESSURE WILL RETURN FOR
SUNDAY AND MONDAY. DRY WEATHER AND MOSTLY SUNNY SKIES EXPECTED.
AN UPPER LEVEL TROUGH WILL LIFT OUT OF THE MIDWEST INTO THE
NORTHEAST EARLY NEXT WEEK AS SURFACE HIGH PRESSURE MOVES OFF THE
COAST. THE ASSOCIATED COLD FRONT WILL SLOWLY APPROACH THE
SOUTHEAST. THE GFS AND ECMWF HAVE COME INTO BETTER AGREEMENT WITH
THE TIMING OF THE FRONTAL PASSAGE. THERE WILL BE A CHANCE FOR
SHOWERS TUESDAY NIGHT INTO WEDNESDAY BEFORE THE FRONT SHIFTS EAST
OF THE CWA WEDNESDAY NIGHT.
&&
.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
VFR/MVFR CONDITIONS EARLY THIS AFTERNOON ARE EXPECTED TO
DETERIORATE TO IFR TONIGHT AND REMAIN IFR THROUGH THE PERIOD.
CEILINGS HAVE FLUCTUATED BETWEEN VFR AND MVFR OVER THE PAST COUPLE
OF HOURS BUT EXPECT MVFR CLOUDS TO OVERSPREAD THE AREA LATE THIS
AFTERNOON AND EVENING AND THEN LOWER TO IFR TONIGHT. THE CHANCE
OF RAIN INCREASES LATE THIS AFTERNOON AND EVENING FROM SOUTHWEST
TO NORTHEAST WITH LIKELY RAIN OVERNIGHT AND INTO FRIDAY. THE
MODELS WERE CONSISTENT KEEPING SURFACE WET BULB TEMPERATURES ABOVE
FREEZING AND WE HAVE INDICATED ALL LIQUID PRECIPITATION AT THE TAF
SITES DURING THE TAF PERIOD. EXPECT MAINLY EAST WINDS 5 TO 10
KNOTS THROUGH THIS AFTERNOON. WINDS OVERNIGHT AND INTO FRIDAY WILL
BE AROUND 10 TO 12 KNOTS WITH GUSTS AROUND 15 KNOTS.
EXTENDED AVIATION OUTLOOK....PRECIPITATION AND WIDESPREAD IFR TO
MVFR CONDITIONS EXPECTED THROUGH SATURDAY. WINTRY PRECIPITATION IS
POSSIBLE SATURDAY. BREEZY CONDITIONS POSSIBLE SATURDAY AND
SATURDAY NIGHT.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...WINTER STORM WARNING FROM 1 AM FRIDAY TO 7 PM EST SATURDAY FOR
SCZ015-016.
FREEZING RAIN ADVISORY FROM 1 AM TO NOON EST FRIDAY FOR
SCZ020>022-029.
&&
$$
SYNOPSIS...99
NEAR TERM...99
SHORT TERM...99
LONG TERM...99
AVIATION...99
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
127 PM EST THU JAN 21 2016
.SYNOPSIS...
MOISTURE WILL INCREASE AHEAD OF LOW PRESSURE APPROACHING FROM THE
WEST. THE LOW WILL BE NEAR THE FORECAST AREA FRIDAY INTO FRIDAY
NIGHT AND ALONG THE NORTH CAROLINA AND VIRGINIA COASTS SATURDAY.
DRYING WILL OCCUR SUNDAY AS THE LOW MOVES FARTHER AWAY AND HIGH
PRESSURE APPROACHES FROM THE WEST.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
LOW PRESSURE OVER THE NORTHWESTERN GULF WILL DEEPEN AND SHIFT
NORTHEASTWARD THROUGH THIS AFTERNOON AND EVENING. CURRENT RADAR
LOOP SHOWS LIGHT RAIN BEGINNING TO MOVE INTO THE SOUTHEASTERN CSRA
THIS AFTERNOON. HAVE LOWERED POPS THROUGH LATE THIS AFTERNOON
BASED ON THE HRRR WHICH APPEARS TO HAVE A GOOD HANDLE ON THE
PRECIP CURRENTLY. STILL EXPECT POPS TO RAMP UP THIS EVENING AS
ISENTROPIC LIFT INCREASES. HAVE FORECASTED ALL LIQUID PRECIPITATION
THROUGH THIS EVENING AS SURFACE WET BULB TEMPERATURES REMAIN ABOVE
FREEZING. CLOUDS HAVE SCATTERED OUT SOME IN THE NORTHERN MIDLANDS
AND CSRA WITH TEMPERATURES RISING A FEW DEGREES HIGHER THAN
PREVIOUSLY FORECAST. HAVE ADJUSTED TEMPERATURES SLIGHTLY BASED ON
TRENDS WITH HIGHS IN THE UPPER 40S TO LOW 50S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
THREAT FOR WINTRY PRECIPITATION WITH SIGNIFICANT IMPACTS
INCREASING ACROSS THE NORTHERN MIDLANDS MAINLY FOR FREEZING RAIN
LATE TONIGHT THROUGH FRIDAY. WINTER STORM WARNING IS NOW IN
EFFECT FOR LANCASTER AND CHESTERFIELD COUNTIES. A WINTER WEATHER
ADVISORY FOR FREEING RAIN HAS BEEN ISSUED FOR NEWBERRY...
FAIRFIELD...KERSHAW AND LEE COUNTIES.
SIGNIFICANT DEEPENING OF THE SURFACE LOW OVER THE LOWER MISSISSIPPI
RIVER VALLEY WILL OCCUR IN RESPONSE TO A NEGATIVE TILTING OF THE
UPPER TROUGH AS IT TRANSITIONS INTO A CLOSED LOW OVER MS/AL.
ISENTROPIC LIFT WILL STRENGTHEN OVER THE REGION TONIGHT INTO
FRIDAY AS THE WARM FRONT SLOWLY LIFTS NORTHWARD. CATEGORICAL POPS
STILL IN ORDER.
CONFLUENT 500MB FLOW OVER THE EASTERN OHIO VALLEY AND NORTHEAST
WILL RESULT IN A STRENGTHENING SURFACE RIDGE OVER THE MID ATLANTIC
AND COLD AIR DAMMING WILL DEVELOP ACROSS THE CAROLINAS INTO THE
CSRA TONIGHT INTO FRIDAY. MODELS HAVE BEEN TRENDING COOLER WITH
SURFACE WETBULB TEMPERATURES FALLING BELOW FREEZING ACROSS THE
NORTHERN AND CENTRAL MIDLANDS BY EARLY FRIDAY MORNING. THIS WILL
LIKELY RESULT IN A PERIOD OF FREEZING RAIN. THERE IS STILL SOME
UNCERTAINTY AS TO HOW FAR SOUTH THE FREEZING RAIN WILL DEVELOP.
BASED ON LATEST GUIDANCE WINTER STORM WARNING HAS BEEN POSTED FOR
NORTH MIDLANDS. THERE IS POTENTIAL FOR SIGNIFICANT ICING. WE WILL
CONTINUE TO MONITOR MODEL TRENDS. IF COLD AIR DAMMING IS STRONGER...
SIGNIFICANT ICING MAY DEVELOP FURTHER SOUTH.
TEMPERATURES TONIGHT ARE EXPECTED TO RANGE FROM AROUND 30 NORTH
MIDLANDS TO AROUND 40 ACROSS THE CSRA AND SOUTHEAST MIDLANDS.
SHOULD SEE LITTLE CHANGE IN TEMPERATURES ON FRIDAY ACROSS THE
NORTH MIDLANDS AS STRONG WEDGE CONDITIONS HOLD. TEMPERATURES WARM
ABOVE FREEZING ON FRIDAY ACROSS THE CENTRAL AND SOUTHERN MIDLANDS
AS WELL AS THE CSRA.
SIGNIFICANT QPF IS FORECAST WITH LIQUID ACCUMULATIONS OF 0.75-1.50
INCHES.
FRIDAY NIGHT AND SATURDAY...SURFACE LOW DEEPENS AND MOVES UP THE
COAST TO NEAR NORFOLK BY 12Z SATURDAY WHILE THE CLOSED UPPER LOW
SLOWLY MOVES OVER THE SOUTHERN APPALACHIANS BY SATURDAY MORNING. MID
LEVEL DRY SLOT FORECAST TO MOVE OVER THE FORECAST AREA FRIDAY NIGHT
INTO EARLY SATURDAY WHICH WILL RESULT IN MUCH LOWER POPS FRIDAY
NIGHT.
THE UPPER LOW WILL DRIFT EAST ACROSS THE CAROLINAS ON SATURDAY WITH
THE CORE OF THE COLD AIR ALOFT MOVING OVER THE FORECAST AREA WITH
500MB TEMPS AS COLD AS -26C TO -27C. 00Z NAM AND GFS SHOW DEEPER
MOISTURE INTO SNOW GROWTH ZONE. WILL GO WITH SNOW SHOWERS ACROSS
MUCH OF THE MIDLANDS AND CSRA SATURDAY MORNING. ACCUMULATION MORE
LIKELY NORTH...SOME LIGHT ACCUMULATION IN THE CENTRAL AND
PIEDMONT.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
SURFACE HIGH PRESSURE AND DRIER AIR WILL RETURN TO THE REGION FOR
SUNDAY AND MONDAY. MODELS ALSO INDICATE UPPER LEVEL RIDGING WITH
MODERATING TEMPERATURES. THE UPPER RIDGE WILL MOVE OFF THE COAST
TUESDAY WITH THE NEXT COLD FRONT MOVING INTO THE AREA. THERE
APPEARS TO BE SLIGHT TIMING DIFFERENCES BETWEEN THE GFS AND ECMWF
WITH THE FRONTAL PASSAGE...ALTHOUGH BOTH MODELS PUSH THE FRONT
OFF THE COAST BY LATE WEDNESDAY WITH BELOW NORMAL TEMPERATURES TO
FOLLOW. HAVE INDICATED A CHANCE OF SHOWERS MONDAY NIGHT INTO
WEDNESDAY.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
VFR/MVFR CONDITIONS EARLY THIS AFTERNOON ARE EXPECTED TO
DETERIORATE TO IFR TONIGHT AND REMAIN IFR THROUGH THE PERIOD.
CEILINGS HAVE FLUCTUATED BETWEEN VFR AND MVFR OVER THE PAST COUPLE
OF HOURS BUT EXPECT MVFR CLOUDS TO OVERSPREAD THE AREA LATE THIS
AFTERNOON AND EVENING AND THEN LOWER TO IFR TONIGHT. THE CHANCE
OF RAIN INCREASES LATE THIS AFTERNOON AND EVENING FROM SOUTHWEST
TO NORTHEAST WITH LIKELY RAIN OVERNIGHT AND INTO FRIDAY. THE
MODELS WERE CONSISTENT KEEPING SURFACE WET BULB TEMPERATURES ABOVE
FREEZING AND WE HAVE INDICATED ALL LIQUID PRECIPITATION AT THE TAF
SITES DURING THE TAF PERIOD. EXPECT MAINLY EAST WINDS 5 TO 10
KNOTS THROUGH THIS AFTERNOON. WINDS OVERNIGHT AND INTO FRIDAY WILL
BE AROUND 10 TO 12 KNOTS WITH GUSTS AROUND 15 KNOTS.
EXTENDED AVIATION OUTLOOK....PRECIPITATION AND WIDESPREAD IFR TO
MVFR CONDITIONS EXPECTED THROUGH SATURDAY. WINTRY PRECIPITATION IS
POSSIBLE SATURDAY. BREEZY CONDITIONS POSSIBLE SATURDAY AND
SATURDAY NIGHT.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...WINTER STORM WARNING FROM 1 AM FRIDAY TO 7 PM EST SATURDAY FOR
SCZ015-016.
FREEZING RAIN ADVISORY FROM 1 AM TO NOON EST FRIDAY FOR
SCZ020>022-029.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
1108 AM EST THU JAN 21 2016
.SYNOPSIS...
MOISTURE WILL INCREASE AHEAD OF LOW PRESSURE APPROACHING FROM THE
WEST. THE LOW WILL BE NEAR THE FORECAST AREA FRIDAY INTO FRIDAY
NIGHT AND ALONG THE NORTH CAROLINA AND VIRGINIA COASTS SATURDAY.
DRYING WILL OCCUR SUNDAY AS THE LOW MOVES FARTHER AWAY AND HIGH
PRESSURE APPROACHES FROM THE WEST.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
CURRENT RADAR TRENDS SHOW THE PRECIPITATION SOUTHWEST OF THE AREA
HAS BEEN SLOWER TO MOVE IN THAN ORIGINALLY ANTICIPATED. HAVE
LOWERED POPS THROUGH EARLY AFTERNOON BASED ON CURRENT TRENDS AND
ADJUSTED POPS THROUGH THIS EVENING BASED ON THE HRRR WHICH APPEARS
TO HAVE A GOOD HANDLE ON THE PRECIP CURRENTLY. HIGH PRESSURE WILL
BE WEDGED INTO THE FORECAST AREA FROM THE NORTH WITH A
STRENGTHENING WARM FRONT SOUTH OF THE AREA TODAY. THE MODELS
INDICATE LITTLE ISENTROPIC LIFT IN THE NORTH SECTION OF THE
FORECAST AREA...BUT INCREASING LIFT IN THE SOUTH PART. THE NAM AND
GFS KEEP MOISTURE SHALLOW IN THE NORTH PART...BUT IT BECOMES
DEEPER IN THE SOUTH. HAVE FORECASTED ALL LIQUID PRECIPITATION
THROUGH THIS EVENING AS SURFACE WET BULB TEMPERATURES REMAIN ABOVE
FREEZING. THE TEMPERATURE GUIDANCE APPEARS TOO WARM BECAUSE OF
THE WEDGE PATTERN TODAY. HAVE FORECASTED HIGHS IN THE MIDDLE TO
UPPER 40S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
THREAT FOR WINTRY PRECIPITATION WITH SIGNIFICANT IMPACTS
INCREASING ACROSS THE NORTHERN MIDLANDS MAINLY FOR FREEZING RAIN
LATE TONIGHT THROUGH FRIDAY. WINTER STORM WARNING IS NOW IN
EFFECT FOR LANCASTER AND CHESTERFIELD COUNTIES. A WINTER WEATHER
ADVISORY FOR FREEING RAIN HAS BEEN ISSUED FOR NEWBERRY...
FAIRFIELD...KERSHAW AND LEE COUNTIES.
SIGNIFICANT DEEPENING OF THE SURFACE LOW OVER THE LOWER MISSISSIPPI
RIVER VALLEY WILL OCCUR IN RESPONSE TO A NEGATIVE TILTING OF THE
UPPER TROUGH AS IT TRANSITIONS INTO A CLOSED LOW OVER MS/AL.
ISENTROPIC LIFT WILL STRENGTHEN OVER THE REGION TONIGHT INTO
FRIDAY AS THE WARM FRONT SLOWLY LIFTS NORTHWARD. CATEGORICAL POPS
STILL IN ORDER.
CONFLUENT 500MB FLOW OVER THE EASTERN OHIO VALLEY AND NORTHEAST
WILL RESULT IN A STRENGTHENING SURFACE RIDGE OVER THE MID ATLANTIC
AND COLD AIR DAMMING WILL DEVELOP ACROSS THE CAROLINAS INTO THE
CSRA TONIGHT INTO FRIDAY. MODELS HAVE BEEN TRENDING COOLER WITH
SURFACE WETBULB TEMPERATURES FALLING BELOW FREEZING ACROSS THE
NORTHERN AND CENTRAL MIDLANDS BY EARLY FRIDAY MORNING. THIS WILL
LIKELY RESULT IN A PERIOD OF FREEZING RAIN. THERE IS STILL SOME
UNCERTAINTY AS TO HOW FAR SOUTH THE FREEZING RAIN WILL DEVELOP.
BASED ON LATEST GUIDANCE WINTER STORM WARNING HAS BEEN POSTED FOR
NORTH MIDLANDS. THERE IS POTENTIAL FOR SIGNIFICANT ICING. WE WILL
CONTINUE TO MONITOR MODEL TRENDS. IF COLD AIR DAMMING IS STRONGER...
SIGNIFICANT ICING MAY DEVELOP FURTHER SOUTH.
TEMPERATURES TONIGHT ARE EXPECTED TO RANGE FROM AROUND 30 NORTH
MIDLANDS TO AROUND 40 ACROSS THE CSRA AND SOUTHEAST MIDLANDS.
SHOULD SEE LITTLE CHANGE IN TEMPERATURES ON FRIDAY ACROSS THE
NORTH MIDLANDS AS STRONG WEDGE CONDITIONS HOLD. TEMPERATURES WARM
ABOVE FREEZING ON FRIDAY ACROSS THE CENTRAL AND SOUTHERN MIDLANDS
AS WELL AS THE CSRA.
SIGNIFICANT QPF IS FORECAST WITH LIQUID ACCUMULATIONS OF 0.75-1.50
INCHES.
FRIDAY NIGHT AND SATURDAY...SURFACE LOW DEEPENS AND MOVES UP THE
COAST TO NEAR NORFOLK BY 12Z SATURDAY WHILE THE CLOSED UPPER LOW
SLOWLY MOVES OVER THE SOUTHERN APPALACHIANS BY SATURDAY MORNING. MID
LEVEL DRY SLOT FORECAST TO MOVE OVER THE FORECAST AREA FRIDAY NIGHT
INTO EARLY SATURDAY WHICH WILL RESULT IN MUCH LOWER POPS FRIDAY
NIGHT.
THE UPPER LOW WILL DRIFT EAST ACROSS THE CAROLINAS ON SATURDAY WITH
THE CORE OF THE COLD AIR ALOFT MOVING OVER THE FORECAST AREA WITH
500MB TEMPS AS COLD AS -26C TO -27C. 00Z NAM AND GFS SHOW DEEPER
MOISTURE INTO SNOW GROWTH ZONE. WILL GO WITH SNOW SHOWERS ACROSS
MUCH OF THE MIDLANDS AND CSRA SATURDAY MORNING. ACCUMULATION MORE
LIKELY NORTH...SOME LIGHT ACCUMULATION IN THE CENTRAL AND
PIEDMONT.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
SURFACE HIGH PRESSURE AND DRIER AIR WILL RETURN TO THE REGION FOR
SUNDAY AND MONDAY. MODELS ALSO INDICATE UPPER LEVEL RIDGING WITH
MODERATING TEMPERATURES. THE UPPER RIDGE WILL MOVE OFF THE COAST
TUESDAY WITH THE NEXT COLD FRONT MOVING INTO THE AREA. THERE
APPEARS TO BE SLIGHT TIMING DIFFERENCES BETWEEN THE GFS AND ECMWF
WITH THE FRONTAL PASSAGE...ALTHOUGH BOTH MODELS PUSH THE FRONT
OFF THE COAST BY LATE WEDNESDAY WITH BELOW NORMAL TEMPERATURES TO
FOLLOW. HAVE INDICATED A CHANCE OF SHOWERS MONDAY NIGHT INTO
WEDNESDAY.
&&
.AVIATION /16Z THURSDAY THROUGH MONDAY/...
VFR/MVFR CONDITIONS THIS MORNING ARE EXPECTED TO DETERIORATE TO
IFR BY TONIGHT.
LOW CLOUDS WILL CONTINUE TO OVERSPREAD THE REGION FROM THE
SOUTHWEST THIS MORNING. CEILINGS HAVE ALREADY LOWERED TO MVFR AT
AGS/DNL/OGB...AND EXPECT CEILINGS TO DROP AT CAE/CUB BY THIS
AFTERNOON. THE MODELS INDICATE INCREASING ISENTROPIC LIFT AND
MOISTURE SPREADING INTO THE FORECAST AREA FROM SOUTHWEST TO
NORTHEAST AHEAD OF APPROACHING LOW PRESSURE. THE CHANCE OF RAIN
INCREASES LATE THIS AFTERNOON AND EVENING FROM SOUTHWEST TO
NORTHEAST WITH LIKELY RAIN OVERNIGHT. THE MODELS WERE CONSISTENT
KEEPING SURFACE WET BULB TEMPERATURES ABOVE FREEZING AND WE HAVE
INDICATED ALL LIQUID PRECIPITATION DURING THE TAF PERIOD. EXPECT
MAINLY EAST WINDS 5 TO 10 KNOTS.
EXTENDED AVIATION OUTLOOK....PRECIPITATION AND WIDESPREAD IFR TO
MVFR CONDITIONS EXPECTED THROUGH SATURDAY. WINTRY PRECIPITATION IS
POSSIBLE SATURDAY. BREEZY CONDITIONS POSSIBLE SATURDAY AND
SATURDAY NIGHT.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...WINTER STORM WARNING FROM 1 AM FRIDAY TO 7 PM EST SATURDAY FOR
SCZ015-016.
FREEZING RAIN ADVISORY FROM 1 AM TO NOON EST FRIDAY FOR
SCZ020>022-029.
&&
$$
AREA FORECAST DISCUSSION
NWS JACKSON MS
1029 AM CST THU JAN 21 2016
.UPDATE...RAIN AND THUNDERSTORMS WERE WIDESPREAD THIS MORNING OVER NW
AND WC PORTIONS WITH SOME INTENSE THUNDERSTORMS OCCURRING ALONG ITS
SOUTHERN FLANK. HRRR SEEMS TO BE HANDLING THE CURRENT SITUATION AND
ITS SCENARIO FOR THIS AFTERNOON LOOKS REASONABLE AS WELL.
CLOUDINESS IS CURRENTLY BREAKING UP IN THE WARM SECTOR OVER SOUTH
MS. EXPECT THIS TO CONTINUE AS TEMPS WARM THROUGH THE 60S INTO THE
LOWER 70S THERE. THIS WILL ALLOW CAPES TO JUMP UP TO 1500-2000 J/KG
WITH VERTICAL TOTALS NEAR 30. HRRR IS INDICATING SOME SUPERCELL
STRUCTURES IN FORECAST REFLECTIVITY WITH HIGH UPDRAFT HELICITIES
INDICATING POTENTIAL FOR LARGE HAIL AND A FEW TORNADOES./26/
&&
.AVIATION...WARM FRONT EXTENDED ALONG A AEX-JAN-HBG LINE AT 16Z. AS
TEMPS WARM INTO THE 60S ALONG AND SOUTH OF THIS LINE...EXPECT
CIGS/VSBYS TO BECOME HIGH MVFR IF NOT VFR. TO THE NORTH...CONDITIONS
WILL REMAIN MOSTLY IFR IN STRATUS...FOG AND RAIN. AFTER
00Z...CONDITIONS EVERYWHERE WILL FALL BACK TO IFR AS A COLD FRONT
MOVES THROUGH THE AREA./26/
&&
.PREV DISCUSSION... /ISSUED 450 AM CST THU JAN 21 2016/
SHORT TERM...TODAY THROUGH FRIDAY NIGHT...A VERY COMPLEX WEATHER
SITUATION LOOKS TO UNFOLD OVER THE NEXT 24 TO 48 HOURS ACROSS THE
ARKLAMISS REGION. CURRENTLY A RATHER MOIST AIRMASS IS FILTERING BACK
INTO THE REGION AS INDICATED BY THE PRESENCE OF FOG ACROSS THE AREA.
SOME LOCATIONS ARE SEEING PATCHY DENSE FOG THIS MORNING WHICH SHOULD
STICK AROUND FOR AT LEAST A LITTLE BIT AFTER DAYBREAK. THE FRONT THAT
MOVED INTO THE REGION YESTERDAY HAS STALLED GENERALLY ALONG THE
HIGHWAY 84 CORRIDOR AND THIS WILL ALSO HELP WITH FOG DEVELOPMENT
THROUGH THIS MORNING. CURRENT ANALYSIS INDICATES A SFC LOW THAT HAS
DEVELOPED ACROSS NORTHERN TEXAS AND AN UPPER LEVEL TROUGH/LOW OVER
CENTRAL KANSAS. IT IS THESE TWO FEATURES THAT WILL PLAY PIVOTAL ROLES
IN THE EVOLUTION OF OUR WEATHER THROUGH THE NEXT TWO DAYS. SHOWERS
HAVE DEVELOPED ACROSS THE SOUTHERN PART OF MY CWA IN ASSOCIATION WITH
THIS STALLED FRONT/WARM FRONT AND DISCRETE STORMS ARE MOVING EAST
ACROSS CENTRAL LOUISIANA.
OVERALL THE THINKING OF THE ATMOSPHERIC SET UP HAS NOT CHANGED FOR
TODAY. THROUGH THE MORNING...THE FRONT WILL MOVE BACK NORTH AS A
WARM FRONT. AS THIS DOES...WARM MOIST AIR WILL SURGE BACK NORTH
ACROSS AT LEAST THE SOUTHERN HALF OF THE ARKLAMISS REGION. AS THIS
OCCURS THE SFC LOW OVER TEXAS WILL TRACK EAST AND DEEPEN. AHEAD OF
THIS FEATURE AND ASSOCIATED COLD FRONT...TEMPERATURES IN THE WARM
SECTOR WILL RISE INTO THE 60S AND POSSIBLY EVEN 70S ACROSS THE
SOUTHERN PART OF THE CWA. THIS WILL HELP DESTABILIZE THE ATMOSPHERE.
MODELS INDICATE THAT WHILE DEWPOINTS WILL ONLY REACH THE MID 50S TO
LOWER 60S ACROSS THE WARM SECTOR...THERE SHOULD BE AROUND 700-1200
J/KG OF MUCAPE PRESENT. THIS...ALONG WITH AROUND 28C VERTICAL TOTALS
AND 60KTS OF DEEP LAYER SHEAR...SHOULD HELP GENERATE STRONG TO
SEVERE THUNDERSTORMS ACROSS THE REGION. THESE STORMS MAY BE ISOLATED
TO SCATTERED AT FIRST BEFORE CONGEALING INTO A SQUALL LINE ACROSS
WEST CENTRAL MS AND TRACKING EAST THROUGH THE REST OF THE CWA DURING
THE EVENING HOURS. THE PRIMARY RISK WITH THESE STORMS WILL BE FROM
DAMAGING WINDS AND HAIL AND GIVEN THE AMOUNT OF WIND SHEAR THERE
WILL ALSO BE RISK OF TORNADOES. OVERALL THE CONFIDENCE AND AREA
OUTLOOKED PREVIOUSLY SEEMS GENERALLY ON TRACK STILL. THE OVERALL
TRACK OF THE SFC LOW WILL DICTATE HOW MUCH OF THE REGION OR WHICH
PARTS OF THE REGION WILL SEE THE SEVERE WEATHER. THE MAIN AREA IN
QUESTION AS TO HOW MUCH SEVERE WEATHER COULD BE SEEN IS THE
NORTHWEST. CURRENTLY MODELS ARE IN GOOD AGREEMENT THAT THE SFC LOW
WILL TRACK GENERALLY FROM NATCHEZ TO THE JACKSON METRO AREA TO
COLUMBUS. POINTS ALONG AND SOUTH OF THIS TRACK WILL BE PRIMED FOR
POTENTIAL TO SEE SEVERE WEATHER...WHEREAS NORTH OF THIS WILL LIKELY
REMAIN TOO STABLE TO SEE MUCH IF ANY...THOUGH SOME ELEVATED STORMS
THAT COULD PRODUCE HAIL COULD BE POSSIBLE. THAT BEING SAID...WILL
CONTINUE TO WITH CURRENT HWO/GRAPHICS AS IS. IN ADDITION TO THE
SEVERE THREAT...THERE WILL BE A RISK FOR HEAVY RAIN GIVEN MULTIPLE
ROUNDS OF STORMS FROM THIS MORNING ALONG THE WARM FRONT TO THE MORE
VIGOROUS CONVECTION LATER THIS AFTERNOON. EVEN THOUGH WE HAVE NOT
SEEN RAIN IN A WHILE...VEGETATION THIS TIME OF YEAR DOESNT ABSORB
THE RAINFALL AS EFFICIENTLY. WILL ALSO KEEP THE FLOODING OUTLOOK AS
IS. HI-RES GUIDANCE ALSO AGREES THAT THE BEST TIMING SHOULD BE
AROUND NOON TO 9-10PM.
AS THE SFC LOW MOVES NORTHEAST TOWARD THE TENNESSEE VALLEY...THE
UPPER LOW WILL BE LAGGING SHORTLY BEHIND. AS THIS MOVES ACROSS THE
REGION...WRAPAROUND MOISTURE WILL MIX WITH THE INCOMING COLD AIR TO
GENERATE A WINTER WEATHER POTENTIAL FOR AT LEAST THE NORTHERN PART
OF THE CWA IN THE EARLY MORNING HOURS OF FRIDAY. /28/
CONCERNING WINTER WEATHER POTENTIAL...SIGNIFICANT SNOWFALL REMAINS A
POSSIBILITY OVER NORTHERN PORTIONS OF THE ARKLAMISS FROM LATE
THURSDAY NIGHT THROUGH MUCH OF FRIDAY. FARTHER SOUTH...FLURRIES OR
EVEN A FEW PERIODS OF LIGHT SNOW POSSIBLE DOWN TO THE I-20
CORRIDOR...WITH SOME DRIZZLE OR FREEZING DRIZZLE A CONCERN AS WELL.
MODEL CONSENSUS SEEMS TO HAVE SETTLED ON A TRACK OF THE MID/UPPER
LOW ACROSS NRN LA AND NW/NRN PORTIONS OF THE ARKLAMISS...WITH THE
ECMWF/GEM FARTHEST SOUTH. THE GFS SOLUTION OFFERS MORE OF A MIDDLE
ROAD AND WILL FOLLOW CLOSER TO ITS DETAILS WHICH MATCH UP WELL WITH
THE PREVIOUS FORECAST. ASIDE FROM THE LOW POSITIONING AND CORRELATED
PRECIP AMOUNTS...THERE ARE UNCERTAINTIES INVOLVING PRECIPITATION
TYPE AS WARMER MID LEVEL AIR COULD BE SUFFICIENT FOR SLEET TO MIX IN
WITH SNOW...AND OF COURSE THE TIMING OF RAIN TO FROZEN PRECIP IS
ALWAYS A BIG QUESTION IN THIS SET-UP. IT SEEMS A CONSENSUS POINTS TO
THE 09-12Z TIME FRAME FOR A CHANGE-OVER TO FROZEN PRECIP IN THE
DELTA REGION...WITH THE TRANSITION ZONE MOVING EAST ACROSS CENTRAL
MS LATER IN THE MORNING. THE INHERITED FORECAST MAY HAVE BEEN A
LITTLE TOO FAST IN THIS REGARD...BUT WILL KEEP IT ROUGHLY THE SAME
TO MAINTAIN CONSISTENCY WITH THE WATCH PRODUCT. IN THE END...SNOW
AMOUNTS COULD STILL BE JUST AS...IF NOT MORE SIGNIFICANT THAN
PREVIOUSLY ANTICIPATED...BUT A LITTLE MORE DELAYED.
THE MAIN CHANGES IN THIS FORECAST WERE TO EXPAND THE WATCH TO
INCLUDE SE ARKANSAS AND WASHINGTON COUNTY BASED ON IDEA OF QUICKER
STRENGTHENING AND STRONGER LIFT WITH THE MID LEVEL LOW PREVIOUSLY
DISCUSSED...WHICH WOULD SUGGEST A SNOW SWATH WITH A LITTLE MORE OF A
SW-NE ORIENTATION FOR THE HEAVIER AMOUNTS OVER NRN PORTIONS OF THE
DELTA REGION. HAVE COORDINATED WITH WPC TO BUMP UP AMOUNTS SOME IN
THE WATCH AREA...BUT CONFIDENCE IS STILL NOT HIGH ENOUGH TO WARRANT
AN UPGRADE. FOR LOCATIONS SOUTH OF THE WATCH AREA AND DOWN TO THE I-
20 CORRIDOR...ICE CRYSTAL GROWTH NECESSARY FOR SNOW WILL BE MORE
FLEETING GIVEN MORE SHALLOW MOISTURE AND LIFT...BUT STRONG COLD
ADVECTION WILL CERTAINLY SQUEEZE OUT SOME DRIZZLE WHICH COULD BECOME
PROBLEMATIC BY FRIDAY EVENING WHEN THE TEMPERATURE IS EXPECTED TO
DROP BELOW FREEZING...AND THE NEAR SURFACE LAYER COULD BECOME COLD
ENOUGH FOR SNOW GRAIN PRODUCTION. IN ANY CASE...PRECIPITATION
AMOUNTS SHOULD BE LIGHT AND SNOW AMOUNTS STILL LOOK INCONSEQUENTIAL
FARTHER SOUTH. /EC/
WHILE WARM CONDITIONS WILL BE PREVALENT TODAY...STRONG COLD AIR
ADVECTION WILL MOVE IN BEHIND THE FRONT AND FRIDAY WILL BE A RATHER
RAW AND MISERABLE DAY ACROSS MUCH OF THE REGION. LOCATIONS ACROSS
THE HIGHWAY 82 CORRIDOR WILL STRUGGLE TO GET OUT OF THE 30S DURING
THE DAY...ESPECIALLY WITH SNOWFALL OCCURRING AND MAY LINGER NEAR
FREEZING FOR MUCH OF THE DAY. IN ADDITION...NORTH/NORTHWESTERLY WINDS
WILL BE RATHER BLUSTERY WHICH MAY RESULT IN BLOWING/DRIFTING SNOW
AT TIMES. GUIDANCE INDICATES THAT SPEEDS OF 30MPH WILL BE POSSIBLE
WITH HIGHER GUSTS AND THIS COULD WARRANT A WIND ADVISORY FOR
PORTIONS OF THE DELTA ON FRIDAY. THE WIND AND COLD COMBINED WILL
CREATE WIND CHILLS IN THE 20S ACROSS MOT OF THE AREA DURING THE DAY
ON FRIDAY AND THE UPPER TEENS IN THE DELTA. /28/
LONG TERM...SATURDAY THROUGH NEXT WEDNESDAY...AFTER A VERY ACTIVE
SHORT TERM PERIOD (THURSDAY AND FRIDAY)...OTHER THAN A SMALL "BUMP
IN THE ROAD" MONDAY INTO TUESDAY...THE LONG TERM PORTION OF THE
FORECAST CURRENTLY APPEARS RATHER SUBDUED.
AS THE SURFACE LOW CONTINUES TO LIFT NORTHEAST UP THE EAST COAST AND
THE WESTERN PERIPHERY OF THE UPPER TROUGH EXITS THE REGION...CLOUDS
AND ANY POSSIBLE LINGERING FLURRIES SHOULD EXIT THE CENTRAL AND
EASTERN PORTIONS OF THE FORECAST AREA SATURDAY MORNING. DESPITE THE
CLEARING SKIES...A RATHER BRISK DAY IS EXPECTED AS HIGHS SATURDAY
AFTERNOON RANGE FROM THE MID 30S TO MID 40S. THESE COLD TEMPERATURES
WILL BE BACKED BY NORTHERLY WINDS BETWEEN 10-15 MPH...GUSTING UP TO
AROUND 20 MPH AT TIMES...PRIMARILY THROUGH MID-AFTERNOON. THIS
COMBINATION OF COLD TEMPERATURES AND WINDS WILL RESULT IN AFTERNOON
WIND CHILLS RANGING FROM THE UPPER 20S TO UPPER 30S. CLEAR SKIES
AND LIGHT TO CALM WINDS ARE EXPECTED SATURDAY NIGHT AS A SURFACE
HIGH SHIFTS OVER THE REGION. THIS WILL CAUSE OVERNIGHT LOWS TO
PLUMMET INTO THE LOW TO MIDDLE 20S AREAWIDE.
A BRIEF WARMING TREND WILL BEGIN ON SUNDAY AND CONTINUE INTO MONDAY
AS THE SURFACE HIGH SHIFTS EAST OF THE CWA...AND FLOW ACROSS THE
REGION BECOMES SOUTHERLY. STILL...AN OVERALL SEASONABLE DAY WILL BE
ON TAP AS HIGHS RANGE FROM THE MID 40S TO MID 50S UNDER SUNNY SKIES.
CLOUDS WILL INCREASE SUNDAY NIGHT INTO MONDAY MORNING AS LOWS RANGE
FROM THE MID 30S TO MID 40S. HIGHS MONDAY UNDER MOSTLY CLOUDY SKIES
WILL RANGE FROM THE UPPER 50S TO MIDDLE 60S...AND FALL INTO THE
UPPER 30S TO UPPER 40S MONDAY NIGHT.
THE BEFORE MENTIONED INCREASE IN CLOUDS SUNDAY NIGHT INTO MONDAY
MORNING IS RESPONSE TO AN UPPER LEVEL TROUGH SWINGING ACROSS THE
NATION`S MID-SECTION MONDAY INTO TUESDAY. THIS WILL SEND ANOTHER
COLD FRONT INTO AND THROUGH THE FORECAST AREA MONDAY EVENING INTO
TUESDAY. THIS WILL ALSO BRING AN INCREASE IN RAIN CHANCES FROM
MONDAY AFTERNOON THROUGH TUESDAY AFTERNOON. RAIN LOOKS TO COME TO
AN END TUESDAY EVENING...WITH GRADUAL CLEARING AND COOL CONDITIONS
EXPECTED TUESDAY NIGHT THROUGH WEDNESDAY. HIGHS BOTH TUESDAY AND
WEDNESDAY WILL BE FROM THE MID 40S TO MID 50S. LOWS TUESDAY AND
WEDNESDAY NIGHTS WILL FALL INTO THE 30S. /19/
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 63 39 40 28 / 95 100 53 9
MERIDIAN 61 41 42 30 / 92 100 51 9
VICKSBURG 52 40 41 28 / 95 95 53 6
HATTIESBURG 71 45 45 28 / 92 100 22 6
NATCHEZ 66 42 42 27 / 95 86 32 5
GREENVILLE 54 34 36 28 / 96 97 90 7
GREENWOOD 56 35 36 26 / 96 100 90 8
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...WINTER STORM WATCH FROM LATE TONIGHT THROUGH FRIDAY AFTERNOON
FOR MSZ018-019-025>029-034.
LA...NONE.
AR...WINTER STORM WATCH FROM LATE TONIGHT THROUGH FRIDAY AFTERNOON
FOR ARZ074-075.
&&
$$
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
241 PM CST THU JAN 21 2016
.SHORT TERM: (Through Friday)
Issued at 240 PM CST Thu Jan 21 2016
Deep trof with two very distinct vortices is continuing to dig
across the eastern Plains. The northern vortex is over eastern
Kansas producing some light snow...while the southern vortex is is
moving along the Oklahoma Texas border. Our CWFA is on the fringes
of influence of both of these vortices, and dry low level air is
being pulled from the east-northeast across the area as the surface
reflection of the trof deepens over Louisiana. This dry low level
flow more or less evaporated much of our precip this morning, and it
will continue to keep us dry tonight into Friday. Most short range
guidance is in agreement that accumulating precip will stay south
and east of the area through Friday...with the notable exception of
the HRRR which does show some light snow overnight across our
southern counties. Kept some low chance PoPs in southern zones to
cover this eventuality. Temperatures in the column should be cold
enough for snow...if anything should fall. Should see temperatures
continue to moderate with lows tonight generally in the upper teens
and highs Friday in the low 30s. We might even break through the
freezing mark across our southern zones.
Carney
.LONG TERM: (Saturday through Next Thursday)
Issued at 240 PM CST Thu Jan 21 2016
(Saturday and Sunday)
Focus will be temps with sfc ridge building into the region thru the
weekend.
With the sfc ridge building into the area Fri night, expect clouds
to gradually clear with system pulling newd out of the region. Winds
will gradually diminish, but perhaps more slowly. These two
features will have a large impact on temps overnight and will likely
end up with a large temp spread across the CWA. Given how quickly
temps can drop as winds become light and with potentially some snow
left, have trended twd the cooler guidance.
With upper level ridging and strong swly low level winds building
the thermal ridge into the region thru the later half of the
weekend, have trended twd the warmer guidance. Going forecast for
Sun may still be too cool. However, one concern is that sfc winds
may be more sely than sly or swly.
(Monday through Thursday)
Focus turns to system approaching the CWA on Mon. Mdls have come
into very good agreement regarding mass fields for this system. Some
timing differences still exist, but are in remarkably good agreement
for day 5. With the better agreement, have begun to fine tune the p-
types for this system. Given thermal profiles, believe this will be
mainly a light RA event. Cold air will move in behind the system Mon
afternoon into Mon night. There is a fair amount of uncertainty in
how quickly this will occur. Have therefore kept mention of RA thru
Mon, but trended twd a RA to mix to SN for Mon night.
With low level wly flow late in the period, have moderated temps for
now. Some timing differences on the next s/w to approach the region
into Thurs. Little if any precip is anticipated, but timing of this
trof may impact temps.
Tilly
&&
.AVIATION: (For the 18z TAFs through 18z Friday Afternoon)
Issued at 1148 AM CST Thu Jan 21 2016
Tricky ceiling forecast along the I-70 corridor today. In general,
MVFR cigs around 1500 ft will prevail along and south of I-70
today...but drier air is trying to cut into these low ceilings
from the northeast. Should see this dry air make better progress
tonight as strengthening low pressure moves up through
Mississippi and turns the low level flow to the north-northeast.
Another area of low clouds over the Upper Midwest will be pushed
southward toward our area Friday morning...but I think they
should stay up across Iowa into central Illinois until Friday
afternoon.
Specifics for KSTL:
Lambert looks to be on the northern edge of the MVFR stratus
today. Handled it by prevailing 1500 ft, but perhaps a TEMPO would
have been more appropriate. Will monitor for an hour or two and
see how the trends go. Should see the MVFR push south tonight as
the wind becomes more north-northeasterly, blowing in drier low
level air. Another area of low clouds over the Upper Midwest will
be pushed southward toward our area Friday morning...but I think
they should stay up across Iowa into central Illinois until Friday
afternoon.
Carney
&&
.PRELIMINARY POINT TEMPS/POPS:
Saint Louis 19 32 22 36 / 10 10 5 0
Quincy 17 28 14 32 / 5 10 0 0
Columbia 17 30 16 35 / 10 5 5 0
Jefferson City 19 32 17 36 / 10 5 5 0
Salem 22 31 20 34 / 10 10 5 0
Farmington 21 31 20 35 / 20 20 10 0
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1200 PM CST THU JAN 21 2016
.SHORT TERM: (Through Late This Afternoon)
Issued at 403 AM CST Thu Jan 21 2016
Vort max which is showing up nicely on water vapor near the MO/AR
border as of 1000 UTC and is moving northeasward toward central
Missouri. The 0000 UTC models failed to capture this vort and
associated precipitation but the recent runs of the HRRR and RAP have.
The HRRR/RAP does weaken this area of precipitation with
time...but each successive run of the each model weaken it a bit
later than the previous run. Have upped PoPs into the likely
category for far western CWA due to the nice signature on WV
imagery. Best chance for this snow activity will be across
Boone/Moniteau/Osage counties. Amounts should be light (under half
an inch). This area will need to be monitored through the morning
hours and further updates may be necessary if the precipitation
shield maintains its strength over the next several hours.
Portions of southeast Missouri may also need PoPs adjusted upward
if this does occur.
Otherwise...expect a cloudy day with highs several degrees below
normal for mid/late January.
Gosselin
.LONG TERM: (Tonight through Wednesday)
Issued at 403 AM CST Thu Jan 21 2016
(Tonight- Wednesday)
Main system begins to develop and deepen beginning tonight across
the lower Mississippi Valley. Still appears even our far southern
CWA will be too far north to receive any signigicant snow
accumulations. Though cannot totally rule out some light snow on
northern periphery of this system across portions of southeastern
Missouri and southwest Illinois either tonight or on Friday due to
some weak WAA and UL divergence associated with RER of jet streak
aloft.
System will continue to deepen and move off to the east-northeast
away from the area leaving light northerly sfc winds in its wake.
Surface ridge moves into the area on Saturday with seasonable
temperatures continuing.
By Sunday...return flow around aforementioned high and rapidly
rising heights aloft signal a quick warmup ahead of the next system.
High temperature forecast will be tricky/complicated by amount of
mid/high level cloudiness and remaining snow cover. Continued to
lean warm for most areas...but particularly so for areas with little
existing snowcover.
Next system to affect the mid-Mississippi Valley continues to look
like mainly a light rain/snow situation as the sfc low tracks across
roughly the middle of the CWA and transverses the area fairly
quickly. Temperatures out ahead of the system on Monday look to be
above normal before falling back to near normal behind the system on
Tuesday and Wendesday.
Gosselin
&&
.AVIATION: (For the 18z TAFs through 18z Friday Afternoon)
Issued at 1148 AM CST Thu Jan 21 2016
Tricky ceiling forecast along the I-70 corridor today. In general,
MVFR cigs around 1500 ft will prevail along and south of I-70
today...but drier air is trying to cut into these low ceilings
from the northeast. Should see this dry air make better progress
tonight as strengthening low pressure moves up through
Mississippi and turns the low level flow to the north-northeast.
Another area of low clouds over the Upper Midwest will be pushed
southward toward our area Friday morning...but I think they
should stay up across Iowa into central Illinois until Friday
afternoon.
Specifics for KSTL:
Lambert looks to be on the northern edge of the MVFR stratus
today. Handled it by prevailing 1500 ft, but perhaps a TEMPO would
have been more appropriate. Will monitor for an hour or two and
see how the trends go. Should see the MVFR push south tonight as
the wind becomes more north-northeasterly, blowing in drier low
level air. Another area of low clouds over the Upper Midwest will
be pushed southward toward our area Friday morning...but I think
they should stay up across Iowa into central Illinois until Friday
afternoon.
Carney
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
National Weather Service Kansas City/Pleasant Hill MO
1130 AM CST THU JAN 21 2016
.DISCUSSION...
Issued at 259 AM CST THU JAN 21 2016
The leading PV area, ahead of the main PV anomaly, was pushing
through eastern Kansas. The main segment of this PV anomaly is
diving into the Southern High Plains and will eject through Texas and
into the southeast, eventually causing a major snowstorm through the
Middle Atlantic into the Northeast. But it`s the leading, more
northerly segment of the overall PV anomaly that has been and will
continue to affect the weather in eastern Kansas and western
Missouri. The dry slot associated with this leading PV is clearly
visible on water vapor imagery and on IR imagery as a decrease in
cloud temperatures. It`s this drop in cloud temperatures, and its
resultant drop and/or removal of cloud ice that makes this forecast
so challenging. -12C to -18C RH plots show this dry slot moving over
eastern Kansas and western Missouri right around sunrise. There is a
good chance for light freezing drizzle to develop as this dry slot
moves over and with overnight temperatures in the lower 20s, it could
make the morning commute treacherous. Later in the morning and this
afternoon, as the mid-level circulation moves into northeastern
Kansas and northwestern Missouri, saturation should develop in the
ice growth region and we should see light snow and/or freezing
drizzle continue. This area of saturation remains over the area
through the night and as a result there is a possibility of seeing
light freezing drizzle and/or light snow persist. But what may
inhibit this is lower level dry air infiltrating back into the
region. Since models don`t depict much/any QPF overnight and
soundings move this drier air underneath the higher level saturation,
will keep any precipitation out of the forecast overnight. But this
could change depending on the actual evolution of the storm and
moisture associated with it.
Shortwave ridging will build into the region for the weekend
allowing for nice warm up into the 40s by Sunday. Then, by Sunday
night through Monday, the next impulse moves into the region. This
system may bring another round of mixed weather to the area,
depending on how quickly we cool off after a frontal passage during
the day Monday. Models are in good agreement with cold enough air
for wintry precipitation across the northwestern portion of the
forecast area. Further south, there is more uncertainty regarding
precip type given the differences in timing and resulting
temperatures.
For now, the weather looks quiet for the remainder of next week. But
one or more clipper type systems may move through the Upper Midwest
and clip the forecast area. But given the origin of any replacing
air mass looks more maritime in nature, another blast of cold air
looks unlikely at this point.
&&
.AVIATION...(For the 18Z TAFS through 18Z Friday Afternoon)
Issued at 1130 AM CST THU JAN 21 2016
Periods of light snow and patchy freezing drizzle will continue
through mid afternoon, before gradually dissipating at all KC area
TAF sites. At KSTJ, only a few light flurries are expected while
the bulk of precipitation remains to the south. At all sites, once
precipitation dissipates MVFR stratus will continue through the
evening and overnight hours, and may linger through the remainder
of the TAF period. Winds will progressively back to the north,
increasing slightly to around 10 kts by early Friday AM.
&&
.EAX Watches/Warnings/Advisories...
KS...Winter Weather Advisory until 5 PM CST this afternoon for KSZ025-
057-060-103>105.
MO...Winter Weather Advisory until 5 PM CST this afternoon for MOZ028-
029-037-043-044-053-054.
&&
$$
DISCUSSION...CDB
AVIATION...Laflin
Area Forecast Discussion
National Weather Service SPRINGFIELD MO
1119 AM CST THU JAN 21 2016
...18Z Aviation Update...
.SHORT TERM...(Today and Tonight)
Issued at 0233 AM CST THU JAN 21 2016
A light wintry mix is again affecting the area as lift ahead of a
subtle shortwave over se KS/ne OK is producing a mix of sleet/snow
showers into our western cwfa as of 230 am. MODOT road reports
indicate some covered/partially covered roads where the precip has
occurred. HRRR and other high resolution models show this precip
moving northeast into much of the rest of the cwfa over the next
few hours, exiting our northern counties by 9-10 am or so. A
little bit of MUCAPE supports some heavier "showery" pockets of
precip. Model soundings show the precip type to be mostly snow
once any dry air saturates/wet bulbs (evaporative cooling), but
some sleet will occur with convective/showery pockets.
Cloud ice quickly diminishes in the wake of the band of precip.
Could see a bit of freezing drizzle today with some weak low level
isentropic upglide persisting over the northern and eastern cwfa.
Will watch trends on that closely today. Will have to take a look
at expanding the advisory farther east as conditions warrant. Not
planning on any changes right now.
Another issue will be the far south central MO/se cwfa as another
stronger shortwave now moving into nw TX moves east into the
lower MS River late tonight. The northern edge of the precip/snow
with this system will affect the MO/AR border region late tonight.
Fcst database has about 1-2 inches of snow for southern Oregon
County. May have to look at that area for an advisory, but it`s
borderline both geographically and by "criteria". There`s time for
the dayshift to take a look.
.LONG TERM...(Friday through Wednesday)
Issued at 0233 AM CST THU JAN 21 2016
The rest of the forecast looks fairly quiet/tame for our area. A
cold Friday will give way to warmer temperatures this weekend as
an upper level ridge builds over the area in the wake of the
developing eastern CONUS storm. There is decent guidance agreement
with another system by late Sunday night into Monday with some
light precip possible (rain...maybe a bit of snow). Colder
temperatures spread back in after the system exits.
&&
.AVIATION...(For the 18Z TAFS through 18Z Friday Afternoon)
Issued at 1116 AM CST THU JAN 21 2016
IFR to occasional LIFR will continue this afternoon at all sites.
Visibility will be restricted at times below 3 SM due to freezing
drizzle and fog.
Freezing drizzle will continue through this evening, before ending
overnight. Low cigs will likely continue for most of the morning
hours on Friday, however.
&&
.SGF Watches/Warnings/Advisories...
MO...Winter Weather Advisory until midnight CST tonight for
MOZ055>058-066>071-077>083-088>098-101>106.
KS...Winter Weather Advisory until midnight CST tonight for KSZ073-
097-101.
&&
$$
SHORT TERM...DSA
LONG TERM...DSA
AVIATION...Boxell
AREA FORECAST DISCUSSION
NWS HASTINGS NE
410 PM CST THU JAN 21 2016
.SHORT TERM...(THIS EVENING THROUGH FRIDAY DAYTIME)
ISSUED AT 410 PM CST THU JAN 21 2016
BIGGEST FORECAST ISSUES INCLUDE THE POTENTIAL FOR FREEZING DRIZZLE
THIS AFTERNOON/EVENING AND FOG THIS AFTERNOON THROUGH FRIDAY MORNING.
THE NAM...WRF...AND TO SOME EXTENT THE HRRR INDICATE THE POSSIBILITY
OF SOME LIGHT PRECIPITATION...AND MODEL SOUNDINGS IN BUFKIT INDICATE
THAT WE COULD BE IN FOR SOME FREEZING DRIZZLE OR FLURRIES...POSSIBLY
LINGERING INTO THE EVENING FOR LOCATIONS ALONG AND EAST OF HIGHWAY
281.
FOG IS STUBBORNLY PERSISTENT FOR AT LEAST A FEW
LOCATIONS...ESPECIALLY HASTINGS AND GRAND ISLAND WHERE IS HAS
BEEN UNDER A MILE FOR AWHILE. CLOUD BASES HAVE BEEN STEADILY
LOWERING TODAY AND COULD HAVE A ROLE IN KEEPING THE FOG
AROUND...DESPITE THE WIND STARTING TO BACK MORE TO THE NORTH AND
INCREASE A BIT. A FEW SHORT TERM MODELS ARE AT LEAST HINTING ON
THE FACT THAT IT MAY BE DIFFICULT TO COMPLETELY SHAKE THE FOG. I
INTRODUCED MORE FOG IN OUR NORTHWEST LATE TONIGHT INTO FRIDAY
MORNING AS WIND BEGINS TO DECREASE WITH THE SURFACE RIDGE
APPROACHING.
KNOCKED TEMPERATURES DOWN A BIT FOR HIGHS FRIDAY IN THE MID TO UPPER
20S FOR MOST AREAS.
.LONG TERM...(FRIDAY EVENING THROUGH THURSDAY)
ISSUED AT 410 PM CST THU JAN 21 2016
ALTHOUGH CONFIDENCE REMAINS RATHER HIGH THAT THE VAST MAJORITY OF
THIS 6-DAY PERIOD CONTINUES TO LOOK PRECIPITATION-FREE...AND THAT
THAT TEMPERATURES SHOULD GENERALLY AVERAGE "NEAR-NORMAL" (MEANING
WITHIN 5 DEGREES ABOVE OR BELOW AVERAGE) IN MOST PLACES ON MOST
DAYS...THIS "FEELS" LIKE A FORECAST THAT COULD END UP BEING BE A
BIT MORE COMPLICATED/COMPLEX THAN EARLIER THOUGHT ESPECIALLY WITH
REGARD TO SKY COVER/TEMPS (FOG POTENTIAL?) OVER THE WEEKEND...AND
THEN THE NEXT POTENTIAL QUICK-HITTING "SNOW-MAKER" THAT SWEEPS
ACROSS SUNDAY NIGHT-MONDAY.
STICKING WITH THE BIG PICTURE BUT CONCENTRATING SOLELY ON
PRECIPITATION/SNOW CHANCES...THE ONLY MENTION OF ANYTHING DURING
THESE 6 DAYS IS SUNDAY EVENING-MONDAY (AT LEAST FOR NOW...LOW
PRECIP CHANCES HAVE BEEN REMOVED FROM THE WESTERN/NORTHERN CWA FOR
SUNDAY DAYTIME). THIS STILL LOOKS LIKE A FAIRLY "MINOR" SYSTEM FOR
SNOW ACCUMULATION POTENTIAL...BUT AS JUST EVIDENCED BY WHAT
HAPPENED OVER MUCH OF OUR SOUTHERN CWA OVER THE PAST 24
HOURS...WHAT APPEAR TO BE "MINOR" SYSTEMS 3-4 DAYS OUT CAN
CERTAINLY TURN INTO SOMETHING MORE WITH TIME...SO THIS NEEDS
MONITORED CLOSELY. AT ANY RATE...THIS SYSTEM REMAINS JUST BEYOND
THE 72-HOUR-OR-CLOSER WINDOW FOR WHICH WE FORECAST OFFICIAL SNOW
ACCUMULATION FOR...AND THUS IT`S STILL TOO SOON TO GET TOO CAUGHT
UP IN THE DETAILS.
TURNING TO TEMPERATURES IN THE BIG PICTURE...WHAT ONCE LOOKED
LIKE A SOMEWHAT MILD WEEKEND HAS SEEN THE PICTURE "MUDDIED" A BIT
BY TWO MAIN FACTORS: 1) WITH THE LATEST ROUND OF SNOW...THE VAST
MAJORITY OF THE CWA NOW HAS AT LEAST 1-2 INCHES OF SNOW ON THE
GROUND...WHICH WILL OBVIOUSLY ACT TO SUPPRESS HEATING POTENTIAL
AND 2) SOME MODELS (ESPECIALLY THE NAM) ARE INSISTING THAT MUCH OF
THE WEEKEND COULD FEATURE STUBBORN/PESKY LOW STRATUS THAT MAY BE
TOUGH TO FULLY SCOUR OUT. HOWEVER...OTHER MODELS (SUCH AS THE GFS)
ARE MORE OPTIMISTIC WITH GENERALLY NO WORSE THAN PARTLY CLOUDY
SKIES...AND THUS BETTER POTENTIAL FOR A MODEST WARM-UP. AS
EVIDENCE OF THIS GROWING UNCERTAINTY FOR WEEKEND
TEMPERATURES...THERE IS A NOTABLE 10-15 DEGREE SPREAD IN
SATURDAY`S HIGH TEMPERATURE FORECAST BETWEEN THE 12Z MET GUIDANCE
(COLDER) AND MAV GUIDANCE (MILDER)...WHICH IS NEVER A GREAT
CONFIDENCE-BOOSTER FOR ONLY BEING 2 DAYS OUT.
WITH THE MAIN BIG PICTURE CONCERNS COVERED...WILL NOW DIVE INTO A
LITTLE MORE DAY-TO-DAY DETAIL IN 12-36 HOUR BLOCKS:
FRIDAY EVENING/NIGHT: CONFIDENCE IS HIGH IN A PRECIPITATION-FREE
NIGHT...AS A MID-UPPER LEVEL RIDGE AXIS OVERSPREADS THE CENTRAL
PLAINS FROM THE WEST. CONFIDENCE IS ALSO HIGH IN WINDS...WHICH
WILL REMAIN FAIRLY LIGHT THROUGH THE NIGHT IN THE EASTERN CWA
CLOSEST TO THE DEPARTING SURFACE RIDGE AXIS...BUT WILL FEATURE
STEADIER 5-15 MPH SOUTHERLY BREEZES ACROSS MOST CENTRAL/WESTERN
COUNTIES (ESPECIALLY AFTER MIDNIGHT) IN THE SOUTHERLY RETURN FLOW
AROUND THE DEPARTING HIGH. UNFORTUNATELY...CONFIDENCE IN CLOUD
COVER AND RESULTANT LOW TEMPERATURES IS A BIT SHAKY...ESPECIALLY
WITH THE NAM MORE INSISTENT ON LINGERING LOW STRATUS OVER THE
AREA. NUDGED UP LOWS SLIGHTLY FROM PREVIOUS...ALTHOUGH THE DEEPER
SNOW- COVERED AREAS OF THE SOUTHERN CWA HAVE THE POTENTIAL TO DROP
BELOW EXPECTATIONS IF SKIES CLEAR. FOR NOW WILL RUN WITH A RANGE
FROM 10-15 DEGREES EAST...TO 15-18 WEST. WOULD NOT BE SURPRISED TO
SEE AT LEAST SOME LIGHT FOG DURING THE NIGHT...BUT OMITTED FROM
THE FORECAST AS SOUTHERLY BREEZES SHOULD KEEP VISIBILITIES FROM
GETTING TOO OUT OF HAND.
SATURDAY DAYTIME-NIGHT: MUCH THE SAME STORY AS FRIDAY NIGHT:
CONFIDENCE REMAINS HIGH IN A DRY FORECAST THROUGH THESE 24 HOURS
AS LINGERING RIDGING ALOFT REMAINS THE DOMINANT LARGE-SCALE
FACTOR...BUT CONFIDENCE IN CLOUD COVER AND ESPECIALLY DAYTIME HIGH
TEMPS IS SOMEWHAT SHAKY. GENERALLY NUDGED DOWN HIGH TEMPS SLIGHTLY
IN THE WESTERN CWA WHILE LEAVING EASTERN AREAS SIMILAR TO
PREVIOUS...THUS RESULTING IN A MODEST GRADIENT FROM MID-30S EAST
TO MID-40S WEST. THE DAY COULD BE SLIGHTLY BREEZY WITH SUSTAINED
SPEEDS UP TO AROUND 15 MPH IN SOME AREAS. AS WINDS SLACKEN
SATURDAY NIGHT...FOG COULD BECOME AN ISSUE...BUT IT`S STILL A BIT
TOO EARLY TO START ADVERTISING FOG THIS FAR OUT.
SUNDAY DAYTIME: THIS IS A DRY FORECAST PERIOD FOR NOW...BUT THIS
IS ASSUMING THAT LIGHT DRIZZLE DOES NOT MATERIALIZE FROM ANY
POSSIBLE LOWER CLOUDS. HIGH TEMPS AGAIN MAINLY MID-30S TO LOW-40S.
SUNDAY NIGHT-MONDAY DAYTIME: AS ALREADY COVERED...THESE 24 HOURS
CONTAIN THE ONLY TRUE PRECIP CHANCES OF THIS ENTIRE LONG TERM
PERIOD...BUT GIVEN IT`S STILL 3+ DAYS AWAY PRECIP CHANCES (POPS)
ARE ONLY AS HIGH AS THE 30-50 PERCENT RANGE. EVEN IF SNOW DOES NOT
ULTIMATELY AMOUNT TO MUCH...WILL HAVE TO WATCH FOR LIGHT FREEZING
DRIZZLE POTENTIAL AS IT GETS CLOSER.
MONDAY NIGHT: AT LEAST FOR NOW...LOOKS PRECIP-FREE BEHIND THE
DEPARTING SYSTEM.
TUESDAY DAYTIME-NIGHT: LOOKS DRY AT THIS TIME...AS MID-LEVEL
HEIGHTS RISE A BIT BEHIND THE DEPARTING SYSTEM. LOW LEVEL WESTERLY
FLOW COULD TRY TO WARM THINGS A BIT...BUT LINGERING SNOW COVER IS
LIKELY A MITIGATING FACTOR.
WEDNESDAY DAYTIME-THURSDAY DAYTIME: THESE LAST FEW FORECAST
PERIODS ARE CURRENTLY DRY...BUT THE LATEST ECMWF SUGGESTS THAT A
QUICK SHOT OF LIGHT PRECIP CANNOT BE RULED OUT FOR WEDNESDAY.
OVERALL THOUGH...THE GENERAL SIGNAL FOR THESE FEW DAYS IS A MODEST
WARM UP AS MILDER AIR TRIES PUSHING IN FROM THE WEST ON LOW-LEVEL
WESTERLIES. MUCH OF THE CWA IS CURRENTLY EXPECTED TO SEE UPPER 30S
TO MID 40S ON THESE DAYS...WITH MAYBE A FEW 50S TRYING TO FLIRT
WITH SOUTHERN/SOUTHWEST ZONES.
&&
.AVIATION...(FOR THE 18Z KGRI/KEAR TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1159 AM CST THU JAN 21 2016
LOW CONFIDENCE FORECAST. KGRI IS QUITE STUBBORN WITH LIFR
VISIBILITY AND NOT QUITE SURE WHEN THIS WILL IMPROVE...BUT SUSPECT
THAT IT WILL NOT BE LONG. MORE THAN ONE MODEL INSISTS ON AT LEAST
MVFR VIS OVERNIGHT...BUT DOES NOT MAKE MUCH SENSE AS WIND WILL BE
FROM THE NORTH NORTHWEST. MIGHT PULL BACK ON THIS IN AN AMENDMENT.
CEILINGS MAY BE QUIRKY AS WELL.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...HEINLEIN
LONG TERM...PFANNKUCH
AVIATION...HEINLEIN
AREA FORECAST DISCUSSION
NWS PENDLETON OR
222 PM PST THU JAN 21 2016
.SHORT TERM...TONIGHT THROUGH SATURDAY NIGHT...PATCHY LIGHT RAIN IS
SHOWING ON RADAR FROM A WARM FRONT THAT IS LIFTING NORTHEAST ACROSS
THE AREA THIS AFTERNOON. THIS PART IF THE PRECIPITATION IS
DISORGANIZED ON RADAR AND MODELS EXCEPT THE HRRR HAVE INDICATED THAT
IT SHOULD HAVE ALREADY ENDED. THE NEXT BAND OF PRECIPITATION WILL
MOVE EAST OF THE CASCADES TONIGHT AS THE COLD FRONT MOVES ONSHORE.
I MAY MAKE LAST MINUTE ADJUSTMENT TO KEEP LIGHT RAIN OVER SOUTHEAST
WASHINGTON RATHER THAN SHOWING A BREAK BETWEEN THE BANDS SHOWN BY
THE MODELS. STRONG SOUTHERLY WINDS DUE TO FUNNELING ARE OCCURRING IN
THE THE SOUTHERN GRANDE RONDE VALLEY WHERE A WIND ADVISORY HAS BEEN
ISSUED. LOCALLY BREEZY WINDS ARE OCCURRING IN THE NORTHEAST OREGON
MOUNTAINS AND FOOTHILLS AS WELL. THE COLD FRONT WILL BE SLOW TO MOVE
INLAND. RAIN AND MOUNTAIN SNOW WILL SPREAD ACROSS THE REGION...AND
SNOW LEVELS WILL FALL TO 4000-5000 FT BY FRIDAY AFTERNOON. THIS
SYSTEM MOVES OUT FRIDAY EVENING BUT ANOTHER ONE MOVES INTO OREGON TO
SPREAD ANOTHER ROUND OF PRECIPITATION WITH LOWER SNOW LEVELS...
AROUND 2000 FT ON THE EAST SLOPES OF THE CASCADES AND 3000-4000 FT
ELSEWHERE BY SATURDAY MORNING. ANOTHER BETWEEN 4000 AND 5000 FEET
FRIDAY AFTERNOON. TEMPERATURES ON SATURDAY WILL ALSO BE LOWER AND
CLOSER TO NORMAL FOR THIS TIME OF YEAR WITH DAYTIME HIGHS IN THE MID
30S TO MID 40S. COONFIELD
.LONG TERM...SUNDAY THROUGH THURSDAY...AN UNSETTLED WEATHER PATTERN
IS GENERALLY EXPECTED THROUGH THIS PERIOD. THE FLOW LOOKS TO BE
SOMEWHAT AMPLIFIED INTO EARLY NEXT WEEK. THUS COULD SEE A MOSTLY DRY
DAY MONDAY AFTER LINGERING SHOWERS ON SUNDAY AND SUNDAY NIGHT. THERE
COULD BE SOME PATCHY FOG AT SOME LOWER ELEVATIONS MONDAY MORNING,
BUT FOR NOW WILL CONTINUE TO ONLY MENTION IN THE GORGE AND THE
KITTITAS VALLEY. ANOTHER SYSTEM LOOKS TO APPROACH THE AREA MONDAY
NIGHT AND TUESDAY, BUT THERE ARE CURRENTLY TIMING DIFFERENCES
BETWEEN THE VARIOUS MID RANGE MODELS. DID SLOW THE ARRIVAL TIMING OF
THIS SYSTEM ON MONDAY NIGHT. OTHER THAN LOWERING POPS ALONG OUR
SOUTHERN BORDER, WILL LEAVE THE TUESDAY INTO WEDNESDAY FORECASTS
LARGELY AS INHERITED. THE FLOW COULD POTENTIALLY BECOME LESS
AMPLIFIED BY LATE WEEK AND WILL CONTINUE THE CURRENT CHANCE TO
LOCALLY LIKELY POPS FOR THURSDAY. 90
&&
.AVIATION...PREVIOUS DISCUSSION...18Z TAFS...A WARM FRONT CONTINUES
TO LIFT NORTH-NORTHEAST ACROSS EASTERN WASHINGTON AND EXTREME
NORTHEAST OREGON. THUS A FEW SHOWERS PERSIST AT OR NEAR KDLS, KYKM,
KPSC, KALW AND KPDT. EXPECT THESE SHOWERS TO LIFT OUT OF THE
VICINITY OF KPSC, KALW AND KPDT BY AFTERNOON. SHOWERS WILL LINGER AT
TIMES NEAR KYKM AND KDLS. VFR CONDITIONS ARE EXPECTED AT KPSC, KALW
AND KPDT THROUGH THE PERIOD, WHILE KDLS WILL BE MAINLY VFR. KYKM
WILL SEE BELOW VFR CONDITIONS AT TIMES THROUGHOUT THIS PERIOD. KRDM
AND KBDN WILL BE VFR WITH SOUTHEAST TO SOUTH WINDS OF 8-12 KTS. A
COLD FRONT WILL BRING SOME RAIN TO MOST IF NOT ALL SITES LATE IN
THIS PERIOD. 90
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 36 54 34 45 / 20 30 20 50
ALW 37 56 36 46 / 20 40 20 50
PSC 38 52 37 45 / 20 50 20 50
YKM 35 45 34 43 / 60 60 40 50
HRI 37 53 36 46 / 20 40 20 50
ELN 34 42 31 40 / 70 70 40 60
RDM 38 49 34 44 / 40 50 50 50
LGD 38 46 34 44 / 10 40 20 50
GCD 33 45 33 42 / 10 50 30 60
DLS 40 52 38 47 / 70 50 50 60
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...WIND ADVISORY UNTIL 3 PM PST FRIDAY FOR ORZ049.
WA...AIR STAGNATION ADVISORY UNTIL 10 AM PST FRIDAY FOR WAZ027.
&&
FOR ADDITIONAL WEATHER INFORMATION, CHECK OUR WEB SITE AT...
WWW.WEATHER.GOV/PENDLETON
$$
76/90/90
AREA FORECAST DISCUSSION
NWS PORTLAND OR
215 PM PST THU JAN 21 2016
.SYNOPSIS...MOIST SOUTHERLY FLOW WILL CONTINUE THROUGH TONIGHT
AHEAD OF A SLOW MOVING COLD FRONT WITH THE COAST AND COASTAL
MOUNTAINS RECEIVING THE HEAVIEST RAINFALL. THE FRONTAL BOUNDARY
EVENTUALLY SPLITS AS IT CONTINUES TO MOVE INLAND TONIGHT AND FRIDAY
MORNING. A LOW WILL APPROACH FROM THE SOUTHWEST FRIDAY NIGHT
AND SATURDAY. SNOW LEVELS WILL LOWER TO NEAR THE CASCADE PASSES OVER
THE WEEKEND. THE PROGRESSIVE WEATHER PATTERN WILL CONTINUE PERIODS OF
RAIN AND CASCADE SNOW INTO NEXT WEEK.
&&
.SHORT TERM...THIS AFTERNOON THROUGH SUNDAY...COLD FRONT SITTING
OFFSHORE HAS MADE LITTLE PROGRESS EAST TODAY. BECAUSE OF ITS SLOW
PROGRESSION...RAIN CONTINUES TO TRAIN OVER CLATSOP COUNTY OR AND
PACIFIC AND WAHKIAKUM WA COUNTIES WITH PLENTY OF REPORTS OF 1.5 TO
2.5 INCHES OF RAIN SINCE MIDNIGHT IN THOSE AREAS. HAVE NOT HAD ANY
REPORTS OF URBAN OR SMALL STEAM FLOODING BUT WILL BE KEEPING A CLOSE
EYE ON THE AREA AS RAIN WILL LIKELY CONTINUE WELL INTO THE EVENING.
UPPED PRECIP AMOUNTS SOME MORE...AGAIN TRENDING TOWARD THE HRRR WHICH
STILL APPEARS TO BE MODELING THE PROGRESSION OF THE FRONT FAIRLY
WELL...SLOWING IT DOWN FURTHER WITH THE LATEST RUNS. THIS ALSO MEANS
RAIN WILL BE SLOW TO ARRIVE INLAND WITH INCREASING CHANCES OF RAIN
EAST OF THE COAST RANGE PROBABLY NOT UNTIL AFTER SUNSET. LOW PRESSURE
RIDING NORTH ALONG THE FRONT WILL SHIFT FLOW FROM OUT OF THE SOUTH
(PARALLEL TO THE FRONT AND THEREFORE NOT HELPING IT MOVE MUCH OF
ANYWHERE) TO OUT OF THE WEST TO SOUTHWEST TONIGHT WHICH SHOULD GIVE
THE FRONT THE NUDGE IT NEEDS TO MOVE ONSHORE AND THROUGH THE LOCAL
AREA. SNOW LEVELS ARE AROUND 8000 FT TODAY BUT WILL DROP TO 4000 TO
5000 FT BY TOMORROW BEHIND THE FRONT. THERE WILL NOT BE MUCH MOISTURE
LEFT BY THE TIME THE SNOW LEVELS COME DOWN BUT COULD SEE SOME LIGHT
SNOW SHOWERS AROUND AN ABOVE PASS LEVEL LATE TONIGHT OR FRIDAY
MORNING.
RAIN SHOULD TAPER OFF FRIDAY WITH THE FRONT EAST OF THE AREA. COULD
EVEN SEE A COUPLE OF GLIMPSES OF THE SUN. THE NEXT SYSTEM IS A LOW
CURRENTLY DEVELOPING ABOUT 800 MILES OFF THE SOUTHERN OREGON COAST.
IT WILL MOVE EAST SOUTHEAST TOWARD THE NORTHERN CALIFORNIA COAST AS
IT STRENGTHENS OVER THE NEXT 18 TO 24 HOURS AND THEN SHIFT NORTHEAST
AND MOVE TOWARD THE OREGON COAST FRIDAY NIGHT. MODELS ARE IN FAIRLY
GOOD AGREEMENT WITH THE LOW MAKING LANDFALL NEAR FLORENCE SATURDAY
MORNING BUT THERE ARE SOME DISCREPANCIES AMONG THE MODELS REGARDING
THE STRENGTH OF THE LOW. HOWEVER IT DOES NOT LOOK LIKE A TERRIBLY
STRONG LOW IN ANY OF THE MODELS SO IT LIKELY WILL NOT CREATE HIGH
IMPACTS FOR THE LOCAL AREA. RAIN AHEAD OF THE LOW LOOK LIKE IT WILL
MOVE INTO THE LOCAL AREA STARTING LATE FRIDAY NIGHT BUT ANY STRONG
WINDS SHOULD REMAIN SOUTH OF THE LOW WHICH BASED ON THE CURRENT TRACK
WOULD LIMIT THEM TO SOUTHERN OREGON. PWATS FRIDAY NIGHT AND SATURDAY
ARE AROUND 0.50 TO 0.75 INCHES SO ALTHOUGH RAIN WILL LIKELY BE STEADY
IT IS NOT EXPECTED TO CREATE ANY FLOODING ISSUES. HOWEVER ANY RIVERS
WHICH ARE ALREADY RUNNING HIGH DUE TO TODAY`S AND TONIGHT`S RAIN
COULD SEE ANOTHER BUMP. SNOW LEVELS WILL REMAIN AROUND 4000 FT FOR
FRIDAY NIGHT`S AND SATURDAY`S PRECIP SO MAY SEE 6 TO 8 INCHES OF SNOW
IN THE CASCADES OVER A 18 TO 24 HOUR PERIOD.
MODELS SHOWING A BRIEF RESPITE FROM RAIN SATURDAY NIGHT AND POSSIBLY
INTO SUNDAY MORNING BEFORE A WEAK TROUGH MOVES INTO THE REGION ALONG
WITH MORE RAIN BY SUNDAY AFTERNOON. AT THIS POINT IT LOOKS LIKE A LOW
QPF SYSTEM SO SUNDAY MAY TURN OUT TO BE MORE DREARY THAN RAINY. BOWEN
.LONG TERM...SUNDAY NIGHT THROUGH THURSDAY. A FAIRLY PROGRESSIVE
PATTERN CONTINUES INTO NEXT WEEK WITH VALLEY RAIN AND MOUNTAIN SNOW
AS FRONTAL SYSTEMS MOVE THROUGH. AN UPPER LEVEL RIDGE WILL TRANSIT
THE REGION MONDAY BRINGING A DECREASE IN PRECIPITATION. WILL LIKELY
SEE A FAIRLY DRY DAY OVER MOST OF THE REGION DURING THE DAY MONDAY
ALTHOUGH SOME UNCERTAINTY EXISTS AS GFS IS DRY...BUT ECMWF KEEPS
SOME PRECIPITATION OVER THE AREA. A WEAK SYSTEM MOVES THROUGH TUES
PM INTO THE WED TIME FRAME...THEN A STRONGER...WETTER SYSTEM
THURSDAY. TW
&&
.AVIATION...COLD FRONT REMAINS OFFSHORE THIS AFTERNOON WITH A
BAND OF HEAVIER RAIN PERSISTING NORTH OF A KTMK TO KKLS LINE...AND
ONLY SCATTERED LIGHT RAIN TO THE SE. EXPECT VFR TO GENERALLY
PREVAIL FOR MOST AREAS WITH CIGS ABOVE 5000 FT...BUT CIGS WILL
LOWER ALONG THE COAST LATER THIS AFTERNOON AS FRONT APPROACHES.
LOWERING CIGS WILL ADVANCE INTO INTERIOR LATE EVENING AND
PARTICULARLY OVERNIGHT WITH PERIODS OF MVFR POSSIBLE ALONG WITH
STEADIER RAIN. MEANWHILE...IN THE STEADY RAIN ALONG THE S
WASHINGTON AND EXTREME N OREGON COAST...PERIODS OF MVFR TO IFR
VSBYS EXPECTED TO CONTINUE.
WINDS WILL TEND TO STAY MOSTLY EASTERLY OR SOUTHEASTERLY ALONG
THE COAST TODAY...AND BRISK EASTERLY THROUGH THE GORGE...TURNING
SOUTH TO SOUTHWEST AND DECREASING ALONG THE COAST LATE TONIGHT AND
INLAND ON FRIDAY. WILL MAINTAIN LLWS IN TAF THROUGH THE EARLY
EVENING AT KTTD WITH STRONG S LOW LEVEL FLOW ABOUT THE BRISK E
SURFACE WIND...BUT THINK CONDITIONS REMAIN BELOW THRESHOLDS AT
KPDX/KVUO.
KPDX AND APPROACHES...SHOWERS AT TIMES THIS AFTERNOON BUT EXPECT
THESE TO BE OCCASIONAL AND LIGHT AND CIGS REMAINING VFR. SURFACE
WINDS E-SE WITH INCREASING S FLOW ALOFT LATER THIS MORNING THROUGH
AFTERNOON...BUT SHOULD REMAIN BELOW THRESHOLD FOR TAF INCLUSION AT
THIS POINT FORWARD. RAIN INCREASES OVERNIGHT AS FRONT PUSHES
THROUGH AREA AND CIGS LOWERING TO MVFR...WITH LIGHTER WINDS AND
DECREASING RAIN ON FRI. CULLEN
&&
.MARINE...SOUTHERLY GALE FORCE GUSTS CONTINUE OVER THE COASTAL
WATERS AHEAD OF A SLOW MOVING COLD FRONT...ALIGNED N-S NEAR THE
BOUNDARY OF THE OUTER WATERS...OR ABOUT 60 NM OFFSHORE. WINDS
WILL TURN SOUTHWESTERLY AND WEAKEN OVERNIGHT TONIGHT AS THE FRONT
PUSHES INLAND. THE NEXT LOW IS EXPECTED TO STAY MOSTLY TO OUR
SOUTH FRIDAY NIGHT AND SATURDAY AS IT MOVES ONSHORE ALONG THE
SOUTHERN OREGON COAST...BUT A SHORT PERIOD OF ADVISORY STRENGTH
WINDS ARE POSSIBLE OVER THE CENTRAL OREGON WATERS. WINDS BEHIND
THE LOW LATER SATURDAY WILL BE NORTHWESTERLY AND MAY REACH
ADVISORY CRITERIA AT TIMES.
SEAS HAVE REACHED THE MID TEENS TODAY AND WILL REMAIN IN THIS
RANGE OVERNIGHT AS A LONG PERIOD SWELL REACHES THE WATERS. THIS
MAY BUILD SEAS AS HIGH AS 17 TO 19 FT...ESPECIALLY OVER THE
CENTRAL OREGON OUTER WATERS. SEAS BEGIN TO GRADUALLY SUBSIDE INTO
THE LOWER TEENS AROUND MIDDAY FRIDAY...AND POSSIBLY BELOW 10 FT
FRIDAY NIGHT...BUT HOLDING IN THE 9 TO 11 FT RANGE THROUGH MUCH OF
THE WEEKEND. CULLEN
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...GALE WARNING UNTIL 10 PM PST THIS EVENING FOR COASTAL WATERS
FROM CAPE SHOALWATER WA TO FLORENCE OR OUT 60 NM.
SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR UNTIL 3 PM
PST FRIDAY.
&&
$$
INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/NWSPORTLAND
WWW.TWITTER.COM/NWSPORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON
FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS
COMMONLY REFERRED TO AS THE FORECAST AREA.
AREA FORECAST DISCUSSION
NWS PORTLAND OR
942 AM PST THU JAN 21 2016
.SYNOPSIS...MOIST SOUTHERLY FLOW WILL CONTINUE THROUGH TONIGHT
AHEAD OF A SLOW MOVING COLD FRONT WITH THE COAST AND COASTAL
MOUNTAINS RECEIVING THE HEAVIEST RAINFALL. THE FRONTAL BOUNDARY
EVENTUALLY SPLITS AS IT CONTINUES TO MOVE INLAND TONIGHT AND FRIDAY
MORNING. A LOW WILL APPROACH FROM THE SOUTHWEST FRIDAY NIGHT
AND SATURDAY. SNOW LEVELS WILL LOWER TO NEAR THE CASCADE PASSES OVER
THE WEEKEND. THE PROGRESSIVE WEATHER PATTERN WILL CONTINUE PERIODS OF
RAIN AND CASCADE SNOW INTO NEXT WEEK.
&&
.UPDATE...WARM FRONT MOVING THROUGH THE AREA THIS MORNING WITH COLD
FRONT OFFSHORE AND MOVING CLOSER. 12Z SLE SOUNDING SHOWS PWAT OF 1.03
INCHES AND MODELS SHOW 1.10 TO 1.20 INCHES NEAR THE COAST AND JUST
OFFSHORE WITH THE COLD FRONT. PUT IN PERSPECTIVE...1.03 INCHES AT SLE
IS NEAR THE HISTORIC MAX PWAT FOR TODAY SO THERE IS A LOT OF
AVAILABLE MOISTURE. MODELS TRENDING HIGHER IN PRECIP AMOUNTS
PARTICULARLY NORTH OF TILLAMOOK COUNTY...SO UPPED QPF FOR THE 18Z-00Z
AND 00Z-06Z TIME PERIODS...NUDGING TOWARD THE HRRR WHICH APPEARS TO
BE MODELING THE PRECIP WELL SO FAR. HIGHEST RAINFALL TOTALS EXPECTED
IN FAR SOUTHWESTERN WASHINGTON AND THE NORTHWEST OREGON COAST AND
COAST RANGE. RIVER FLOODING IS POSSIBLE IN THESE AREAS AND THE HIGHER
QPF CERTAINLY INCREASES THAT LIKELIHOOD. OTHER CHANGE WAS TO DECREASE
POPS INLAND THROUGH THE DAY TODAY AS MODELS ARE TRENDING A BIT SLOWER
WITH THE COLD FRONT. SNOW LEVELS HAVE RISEN TO 7000 TO 8000 FT SO
WILL SEE ALMOST ALL RAIN IN THE CASCADES WITH THIS SYSTEM. BOWEN
.SHORT TERM (PREVIOUS DISCUSSION)...SURFACE LOW ABOUT 550 MILES WEST
OF HAIDA GWAII ANALYZED AT 970 MB. THE ASSOCIATED WARM FRONT
EXTENDS SE TO THE OREGON WATERS BETWEEN ASTORIA AND GRAYS HARBOR.
THE NORTH-TO-SOUTH ORIENTED FRONT LAY ABOUT 300-350 MILES OFF THE
WA/OR COAST. AS EXPECTED THE WARM FRONTAL RAINS TARGETED THE COAST
AND COASTAL MOUNTAIN AREAS OF SW WASH. AND NW OREGON WITH 1/2" TO 1"
OVER THE LAST 6 HOURS. THE INTERIOR LOWLANDS RECEIVED A COUPLE
TENTHS AT BEST IN THE NORTH TO NOTHING IN EUGENE. THIS TREND IS
EXPECTED TO CONTINUE TODAY WITH THE FLOW AHEAD OF THE FRONT FEEDING
1.2" TO 1.4" PRECIPITABLE WATER INTO THE AREA. THE COLD FRONT IS IN
NO HURRY SINCE THE LOW TO HIGH LEVEL WINDS ARE ORIENTED PARALLEL TO
THE FRONT. THERE IS A SHORTWAVE OFF THE CENTRAL CALIFORNIA COAST
THIS MORNING THAT WILL PROVIDE THE KICKER TO SPEED UP EASTWARD
PROGRESS OF THE FRONT LATER THIS AFTERNOON. WITH THIS DELAYED TIMING
HAVE BOOSTED QPF FOR THE COAST AND COASTAL MOUNTAINS CLOSER TO
GFS/NAM SOLUTION.
AS NOTED PREVIOUSLY THE FRONT APPEARS TO SPLIT AND WEAKEN TONIGHT
AND FRI MORNING. NAM...GFS AND ECMWF ALL HAVE A DEVELOPING LOW NEAR
38N 135W 12Z FRI...WHICH ENDS UP COMING ASHORE SOMEWHERE OVER SW
OREGON LATE FRI NIGHT. THIS LOW WILL SEND A WARM FRONT ACROSS NW
OREGON AND SW WASHINGTON FRIDAY NIGHT AND SATURDAY. BETWEEN THESE
TWO FEATURES THERE WILL PROBABLY BE A 8-12 HOUR PERIOD OF LITTLE OR
NO RAIN FRIDAY MORNING AND AFTERNOON.
THE KAST AND KTTD PROFILERS INDICATES A SNOW LEVEL CLOSE TO 8000
FEET. HOWEVER...THE OFFSHORE LOW-LEVEL FLOW WILL RESULT IN MUCH LOWER
SNOW LEVELS IN THE HIGHER VALLEYS OF EASTERN SKAMANIA COUNTY IN
WASHINGTON...AND ALSO THE EAST SLOPES AROUND MT. HOOD. NAM SOUNDING
FOR A VALLEY LOCATION AROUND 2500 FT WEST OF MT. ADAMS SHOWS A SMALL
THREAT OF LIGHT FREEZING RAIN TONIGHT...BUT BELIEVE THE AIR MASS WILL
WARM ENOUGH TODAY TO END THAT THREAT./26
.LONG TERM (PREVIOUS DISCUSSION)...SATURDAY NIGHT THROUGH WEDNESDAY.
LITTLE CHANGE TO THE FORECAST AS MODELS REMAIN IN REASONABLY GOOD
AGREEMENT THROUGH THE PERIOD. UPPER TROUGH SLIDES EAST OF THE
CASCADES BY LATE SATURDAY NIGHT WITH RESIDUAL SHOWERS TAPERING OFF
AS SHORTWAVE RIDGING BUILDS OVER THE REGION IN BETWEEN SYSTEMS.
MODELS SUGGEST THE NEXT DISTURBANCE MAY SPLIT OFFSHORE AS IT
APPROACHES OVERNIGHT SUNDAY...PERHAPS BRINGING SOME LIGHT RAIN AT
TIMES...PARTICULARLY IN SW WASHINGTON...BUT IN LIMITED AMOUNTS.
MONDAY MAY BE DRY AS UPPER LEVEL RIDGE AXIS MOVES OVER THE
AREA...BUT THE NEXT FRONT WILL ARRIVE TUESDAY FOR ANOTHER ROUND OF
PRECIPITATION. THIS WILL BE IN THE FORM OF RAIN FOR MOST LOCATIONS
AS SNOW LEVELS WILL RISE ABOVE 6000 FEET BY LATE MONDAY BEFORE THE
BULK OF THE MOISTURE ARRIVES.
&&
.AVIATION...COLD FRONT REMAINS OFFSHORE THIS MORNING WITH A BAND
OF HEAVIER RAIN PERSISTING NORTH OF A KTMK TO KKLS LINE...AND ONLY
SCATTERED LIGHT RAIN TO THE SE. EXPECT VFR TO GENERALLY PREVAIL
FOR MOST AREAS WITH CIGS ABOVE 5000 FT...BUT CIGS WILL LOWER ALONG
THE COAST THIS AFTERNOON AS FRONT APPROACHES. LOWERING CIGS WILL
ADVANCE INTO INTERIOR THIS EVENING AND PARTICULARLY OVERNIGHT WITH
PERIODS OF MVFR POSSIBLE ALONG WITH STEADIER RAIN. MEANWHILE...IN
THE STEADY RAIN ALONG THE S WASHINGTON AND EXTREME N OREGON
COAST...PERIODS OF MVFR TO IFR VSBYS PROBABLE AT TIMES.
WINDS WILL TEND TO STAY MOSTLY EASTERLY OR SOUTHEASTERLY ALONG
THE COAST TODAY...AND BRISK EASTERLY THROUGH THE GORGE...TURNING
SOUTH TO SOUTHWEST AND DECREASING ALONG THE COAST LATE TONIGHT AND
INLAND ON FRIDAY. WITH SOUTH FLOW ALOFT INCREASING...WILL CONTINUE
TO CARRY LLWS IN TAF AT KTTD AND KPDX THROUGH THE AFTERNOON.
KPDX AND APPROACHES...SHOWERS AT TIMES THIS AFTERNOON BUT EXPECT
THESE TO BE OCCASIONAL AND LIGHT AND CIGS REMAINING VFR. SURFACE
WINDS E-SE WITH INCREASING S FLOW ALOFT LATER THIS MORNING THROUGH
AFTERNOON...SO WILL CONTINUE TO CARRY LLWS IN TAF THROUGH THE
AFTERNOON THOUGH CONDITIONS MAY BE SOMEWHAT MARGINAL. RAIN
INCREASES OVERNIGHT AS FRONT PUSHES THROUGH AREA AND CIGS LOWERING
TO MVFR...WITH LIGHTER WINDS AND DECREASING RAIN ON FRI. CULLEN
&&
.MARINE...A STRONG OCCLUDED LOW PRESSURE SYSTEM WAS OVER THE NE
PACIFIC AND SE GULF OF ALASKA EARLY THIS MORNING...WITH A WARM
FRONT MOVING NORTH THROUGH THE WATERS AND A COLD FRONT OFFSHORE
THAT WILL MOVE THROUGH THE WATERS AND ONSHORE TONIGHT AND EARLY
FRIDAY. THIS SYSTEM WILL CONTINUE TO PRODUCE STRONG GALES IN THE
OUTER WATERS...WITH HIGH END SMALL CRAFT ADVISORY THRESHOLD WINDS
TO LOW END GALES IN THE INNER WATERS. WINDS ALONG THE IMMEDIATE
COAST PROBABLY STAY EAST TO SOUTHEAST THROUGH THE EVENT AND BE
LIGHTER THAN JUST A COUPLE OF MILES OFFSHORE. WINDS WILL TURN
SOUTHWESTERLY AND WEAKEN OVERNIGHT TONIGHT AS THE FRONT PUSHES
INLAND. THE NEXT LOW IS EXPECTED TO STAY MOSTLY TO OUR SOUTH
FRIDAY NIGHT AND SATURDAY. MAINTAINED ADVISORY STRENGTH WINDS INTO
THE CENTRAL OREGON WATERS FOR NOW. WINDS BEHIND THE LOW LATER
SATURDAY WILL BE NORTHWESTERLY AND MAY REACH ADVISORY CRITERIA.
SEAS HAVE REACHED THE MID TEENS EARLY THIS MORNING...AND MAY REACH
THE UPPER TEENS TO NEAR 20 FT IN THE FAR OUTER WATERS TODAY. THE
INNER WATERS AND NEAR THE COAST MAY NOT GET MUCH ABOVE THE MID
TEENS...THOUGH STRENGTHENING EBB CURRENTS MAY PUSH SEAS TO AROUND
20 FT ON THE COLUMBIA RIVER BAR DURING THE STRONGER EBBS. SOME
LONGER PERIOD SWELL AROUND 19 SECONDS MOVES INTO THE WATERS LATE
TONIGHT...MAINTAINING SEAS IN THE MID TO UPPER TEENS TONIGHT AND
EARLY FRIDAY MORNING. SEAS BEING TO GRADUALLY SUBSIDE INTO THE
LOWER TEENS FRIDAY AFTERNOON...AND POSSIBLY BELOW 10 FT FRIDAY
NIGHT. CULLEN
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...GALE WARNING UNTIL 10 PM PST THIS EVENING FOR COASTAL WATERS
FROM CAPE SHOALWATER WA TO FLORENCE OR OUT 60 NM.
SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR UNTIL 6 AM PST
FRIDAY.
&&
$$
INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/NWSPORTLAND
WWW.TWITTER.COM/NWSPORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON
FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS
COMMONLY REFERRED TO AS THE FORECAST AREA.
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
320 PM CST THU JAN 21 2016
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 320 PM CST THU JAN 21 2016
MAIN FORECAST CONCERN IS THE SNOW THIS EVENING AND THEN HOW LONG THE
LOW CLOUDS REMAIN LATER TONIGHT AND TOMORROW.
STRONG UPPER WAVE CURRENTLY IN CENTRAL SD. FAIRLY WIDESPREAD LIGHT
SNOW HAS BEEN FALLING SINCE MID MORNING OVER MUCH OF EAST CENTRAL
SOUTH DAKOTA INTO PARTS OF SOUTHWEST MINNESOTA. A PERSISTENT
AREA OF SNOW DEVELOPED NEAR THE BUFFALO RIDGE FROM WATERTOWN
DOWN INTO LINCOLN COUNTY MINNESOTA. BY MID AFTERNOON THERE WERE
REPORTS OF 2 TO 4 INCHES IN LINCOLN COUNTY WHILE OTHER AREAS HAVE
GENERALLY BEEN LESS THAN 2 INCHES. EXPECTATION IS THAT THIS BAND OF
SNOW WILL PERSIST UNTIL THE UPPER LEVEL WAVE MOVES EAST LATER THIS
EVENING. BASED UPON THE RAP AND SATELLITE...THIS SHOULD END SNOW
NEAR I29 SHORTLY AFTER 00Z AND AROUND KMML BETWEEN 03Z AND 06Z.
LAST OF SNOW SHOULD EXIT COTTONWOOD...JACKSON...AND DICKINSON COUNTY
IOWA BY 09Z. ALONG HWY 14 BETWEEN MARSHALL AND BROOKINGS...ANOTHER
1 TO 2 INCHES OF SNOW IS EXPECTED BRINGING TOTALS TO 4 TO 5 INCHES.
ANOTHER 1 TO 2 INCHES ALSO POSSIBLE AROUND SLAYTON AND WINDOM WHERE
TOTALS WILL BE 1 TO 3 INCHES. ALONG AND SOUTH OF I-90...IN
SOUTHEAST SD AND NORTHWEST IOWA...BAND OF SNOW IS MUCH MORE NARROW
AND PROGRESSIVE SO ANY SNOWFALL WILL LAST ON A FEW HOURS. SNOWFALL
WILL GENERALLY BE LESS THAN AN INCH WITH LITTLE OR NO SNOW AROUND
SIOUX CITY.
SURFACE RIDGE IS EXPECTED TO MOVE SOUTH AND SETTLE ALONG THE WESTERN
MINNESOTA BORDER. NORTHERLY FLOW TONIGHT WILL GRADUALLY WEAKEN LATE.
THIS WILL BRING SOME COOLER AIR INTO THE REGION. HOWEVER...WITH LOW
CLOUDS EXTENDING TO THE INTERNATIONAL BORDER...AM PESSIMISTIC THAT
CLOUDS WILL ADVECT OUT OF THE AREA BEFORE THE SURFACE RIDGE ARRIVES
AND WINDS ALOFT DIMINISH LATER TONIGHT. AFTER THAT...REALLY RELYING
ON SUBSIDENCE TO ERODE CLOUDS. IN THE PAST...THIS HAS BEEN A SLOW
PROCESS TO OCCUR. FOR THAT REASON...EXPECTING SKIES TO REMAIN CLOUDY
ACROSS THE AREA ALL OF TONIGHT WITH BREAKS ONLY SLOWLY DEVELOPING
NORTH OF I90 DURING FRIDAY. THEREFORE...HAVE RAISED MINS TO 1O TO 15
ABOVE SOUTH OF I90 AND 5 TO 10 ABOVE NORTH OF I90. WITH CLOUDS AND
COOLER AIR MASS HIGHS WILL BE BELOW NORMAL WITH TEENS EAST OF THE
JAMES RIVER...AND 20S WEST OF THE JAMES RIVER.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 320 PM CST THU JAN 21 2016
MID-RANGE PORTION OF THE FORECAST WILL FEATURE QUIET CONDITIONS WITH
RELATIVELY MILD TEMPERATURES FOR THE WEEKEND AS UPPER RIDGE BUILDING
INTO THE CENTRAL CONUS ALLOWS WARMER AIR ALOFT TO WORK EASTWARD. AS
IS TYPICAL THIS TIME OF YEAR WITH A DECENT SNOW COVER...FULL EXTENT
OF WARMING WILL NOT BE REALIZED AT THE SURFACE...THOUGH LOCATIONS
WEST OF THE JAMES RIVER VALLEY STAND A STRONG CHANCE OF WARMING
ABOVE FREEZING FOR SEVERAL HOURS ON SATURDAY. WARMING WILL ACTUALLY
BEGIN LATE FRIDAY NIGHT...AS SURFACE RIDGE IN EASTERN FORECAST AREA
EARLY IN THE EVENING SHIFTS EAST...AND AN INCREASE IN SOUTH WINDS
AND THICKER CLOUD COVER BRINGS STEADY TO SLOWLY RISING TEMPERATURES.
CLOUDS WILL STICK AROUND MOST AREAS ON SATURDAY...BUT DECENT MIXING
IN THE STOUT SOUTHERLY FLOW AHEAD OF WEAK COOL FRONT SHOULD HELP
TEMPS WARM INTO THE UPPER 20S-MID 30S ALONG/EAST OF THE JAMES RIVER.
FARTHER WEST...OUR SOUTHWEST CORNER SHOULD SEE A SWITCH TO LIGHTER
WESTERLY FLOW BEHIND THE FRONT...BUT SLIGHT COOLING ALOFT SHOULD
LEAD TO DEEPER MIXING AND HELP WARM HIGHS INTO THE LOWER 40S. COOL
FRONT WORKS THROUGH SATURDAY NIGHT/SUNDAY...BECOMING A STATIONARY
BOUNDARY NEAR SOUTHEAST CWA BY LATE SUNDAY AS STRONGER SYSTEM DIGS
INTO THE CENTRAL PLAINS.
THIS LATE WEEKEND SYSTEM WILL BE OUR NEXT SNOW-PRODUCER FOR EARLY
NEXT WEEK. MODELS PRIOR TO TODAY HAVE BEEN ALL OVER THE PLACE WITH
TIMING/TRACK/STRENGTH OF THIS SYSTEM...BUT NOW THAT POWERFUL EAST
COAST SYSTEM IS COMING INTO CLEARER FOCUS...MODELS HAVE COME INTO
BETTER AGREEMENT ON THE NEXT TROUGH WHICH WILL DIVE THROUGH THE
ROCKIES EARLY NEXT WEEK. 12Z RUNS OF GFS/GEM/ECMWF ALL POINTING TO
CYCLOGENESIS SOMEWHERE IN THE OKLAHOMA PANHANDLE VICINITY BY SUNDAY
EVENING...THEN TRACKING THAT SURFACE LOW TOWARD THE MID-MISSISSIPPI
VALLEY BY LATE MONDAY. WITH FAIRLY GOOD AGREEMENT ON PLACEMENT AND
TIMING OF KEY FEATURES...COORDINATED WITH SURROUNDING OFFICES TO
BUMP POPS INTO LIKELY RANGE ACROSS OUR WEST SUNDAY NIGHT...AND FOR
CENTRAL/EASTERN PORTIONS OF THE FORECAST AREA ON MONDAY. UNCERTAIN
AT THIS POINT HOW MUCH PRECIPITATION/SNOW WILL FALL...BUT MAY HAVE
TO WATCH FOR SOME BANDED PRECIP AS ALL HINTING AT ZONE OF STRONGER
MID-LEVEL FRONTOGENESIS SLIDING ACROSS THE AREA LATE SUNDAY NIGHT
INTO MONDAY. WINDS INITIALLY NOT TOO STRONG...BUT AS LOW BECOMES A
BIT MORE WRAPPED UP ON MONDAY...EXPECT TO SEE AN INCREASE IN NORTH
WINDS WHICH COULD ALSO PRODUCE SOME BLOWING SNOW CONCERNS. AS FAR AS
TEMPERATURES...WILL SEE COOLER AIR MOVE BACK IN FOR MONDAY/TUESDAY
BUT JUST SLIGHTLY BELOW NORMAL.
RETURN TO SOMEWHAT MORE MILD WEST-NORTHWEST FLOW PATTERN SETS UP FOR
MID-LATE NEXT WEEK...BUT WITH LACK OF MODEL AGREEMENT IN TIMING OF
VARIOUS WAVES MOVING THROUGH THE FLOW...SEEING LARGE DIFFERENCES IN
PRECIP TIMING AND LOW LEVEL TEMPERATURE TRENDS. THUS OPTED TO STICK
CLOSE TO BROAD MODEL CONSENSUS FOR OUR WEDNESDAY/THURSDAY PERIODS
FOR NOW.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1231 PM CST THU JAN 21 2016
MAIN CONCERN IN TAF LOCATIONS ARE LOW CLOUDS AND FOG/SNOW OVER THE
NEXT 12 H. MOST LOCATIONS EXPECTED TO HAVE CIGS FROM 500 TO 1500
FT THROUGH 00Z. AT KHON...SNOW IS EXPECTED TO END LATER THIS
AFTERNOON AND EXPECT THAT VSBYS WILL IMPROVE ABOVE 6 SM.VSBYS IN
KFSD WILL BE 3 TO 5 SM EXCEPT WHEN SNOW MOVES THROUGH AND IT COULD
DROP TO A MILE FOR A BRIEF PERIOD. LESS SNOW IS EXPECTED AT KSUX
SO WORST VSBYS WILL BE MVFR. ONCE THE SNOW MOVES THOUGH BOTH
LOCATIONS...ALL LOCATIONS WILL SO CEILINGS SLOWLY INCREASE WITH
VFR CONDITIONS EXPECTED BY FRIDAY MORNING.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
SHORT TERM...SCHUMACHER
LONG TERM...JH
AVIATION...SCHUMACHER
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
328 PM CST THU JAN 21 2016
...A SIGNIFICANT WINTER STORM WILL AFFECT THE MID STATE TONIGHT
THROUGH NOON SATURDAY...
...HAZARDOUS TRAVEL CONDITIONS WILL BECOME WIDESPREAD FRIDAY AND
FRIDAY NIGHT...
.SHORT TERM...IT WAS CLOUDY AND COLD ACROSS THE MID STATE THIS
AFTERNOON, WHILE SHOWERS STARTED WORKING THEIR WAY IN FROM THE
SOUTHWEST. BY 2 PM...THE SHOWERS HAD SPREAD AS FAR NORTHEASTWARD
AS COLUMBIA, AND SHOULD CONTINUE SPREADING EAST AND NORTH AS THE
AFTERNOON AND EVENING WEARS ON. THERE MAY EVEN BE A FEW RUMBLES OF
THUNDER.
TEMPERATURES SHOULD BE WARM ENOUGH OVER MOST OF THE MID STATE
TONIGHT TO ALLOW PRECIPITATION TO BE ALL RAIN. HOWEVER, TEMPS AND
DEW PTS WILL LIKELY REMAIN LOW ENOUGH IN AREAS RIGHT NEAR THE
KENTUCKY BORDER TO ALLOW FOR THE LIKELIHOOD OF A WINTRY MIX OF
RAIN, FREEZING RAIN, SLEET AND SNOW TO FALL. HOWEVER...PRECIP
TONIGHT SHOULD BE LIGHT...WITH SNOW AND SLEET ACCUMULATIONS
MAINLY JUST A FEW TENTHS OF AN INCH. SOME SPOTS COULD ALSO SEE A
THIN GLAZE OF ICE, UP TO AROUND A TENTH OF AN INCH. BECAUSE OF
THE EXPECTED LIGHT GLAZE, WE WILL BEGIN THE WINTER STORM WARNING
TONIGHT IN OUR COUNTIES BORDERING KENTUCKY.
TOMORROW AND FRIDAY IS WHEN THE MAIN WINTER STORM ROLLS IN, AS A
SURFACE LOW PRESSURE CENTER PASSES ACROSS NORTHERN ALABAMA INTO
THE MID-ATLANTIC REGION. SNOW WILL DEVELOP OVER OUR NORTHWESTERN
COUNTIES FRI MORNING, AND BECOME HEAVY BY THE AFTERNOON. SNOWFALL
TOTALS IN THOSE AREAS BY SUNSET FRI SHOULD BE BETWEEN 5 AND 8
INCHES. AS THE LOW PRESSURE AREA PULLS EAST, A SWEEP OF SNOW WILL
ENGULF THE REMAINDER OF THE MID-STATE BY FRI EVENING, AND THEN
TAPER OFF FROM THE WEST LATE FRI NIGHT AND SATURDAY.
NORTHEAST WINDS WILL INCREASE TONIGHT THROUGH FRIDAY NIGHT AS
THIS STORM SYSTEM INTENSIFIES, AND BY FRIDAY AFTERNOON WIND CHILLS
IN OUR NORTHWEST WILL ALREADY BE IN THE TEENS. BY FRIDAY EVENING,
WIND CHILLS WILL REACH THE TEENS AREA-WIDE.
THE WINTER STORM WARNING COVERS ALMOST ALL OF OUR FORECAST AREA
FRIDAY AND FRIDAY NIGHT, WITH THE EXCEPTION OF OUR EXTREME
SOUTHWEST AND SOUTH-CENTRAL COUNTIES, WHERE A WINTER WEATHER
ADVISORY WILL BE IN EFFECT.
TRAVEL CONDITIONS WILL BECOME INCREASINGLY HAZARDOUS, FROM THE
WEST, FRIDAY AND FRIDAY NIGHT AND BY SUNRISE SATURDAY ALL OF THE
MID STATE SHOULD BE UNDER A THICK BLANKET OF SNOW. FRIDAY NIGHT
WILL NOT BE FIT FOR MAN NOR BEAST, AS WINDS WHISTLE OUT OF THE
NORTH, BLOWING THE SNOW AROUND, AND TEMPERATURES DIP INTO THE
LOWER AND MIDDLE 20S.
MOST AREAS WILL LIKELY SEE FREEZING TEMPERATURES THROUGHOUT THE
DAY ON SATURDAY, DUE TO CLOUDS AND SNOW COVER, AND LOWS SATURDAY
NIGHT ARE EXPECTED TO FALL INTO THE TEENS.
WE SHOULD FINALLY SEE TEMPS PUSH BACK ABOVE THE FREEZING MARK ON
SUNDAY.
.LONG TERM...
LOOKING FROM SUNDAY ONWARD, SURFACE HIGH WILL SHIFT EAST OF MIDDLE
TENNESSEE EARLY IN THE WEEK, ALLOWING FOR WARMER TEMPERATURES AND
SETTING THE TABLE FOR THE NEXT COLD FRONTAL PASSAGE MONDAY NIGHT
OR EARLY TUESDAY. WITH THE SURFACE LOW PROJECTED FAR TO OUR NORTH
(GREAT LAKES), WE PROBABLY WON`T SEE ANY WRAP-AROUND EFFECTS WITH
THIS SYSTEM, ALTHOUGH THERE MAY BE A RAIN/SNOW MIXTURE ALONG THE
HIGHLAND RIM ON THE TAIL END AS THE POST-FRONTAL AIR MOVES IN AND
THE MOISTURE EXITS.
&&
.AVIATION...
18Z TAF DISCUSSION.
BNA/CKV/CSV...MOISTURE CONTINUES TO ADVECT NE`WD INTO MIDDLE
TENNESSEE AS A SURFACE LOW TRACKS FROM THE GULF COAST TOWARD THE
TENNESSEE VALLEY. HRRR SHOWS RAIN MOVING INTO MIDDLE TENNESSEE
THIS AFTERNOON, REACHING BNA & CKV AROUND 23Z, THEN THE PLATEAU
DURING THE EVENING. AS THE LOW CONTINUES TO MOVE TOWARD THE E/NE,
WINDS WILL TURN MORE NE`WD WITH FALLING TEMPERATURES AND WINTRY
PRECIPITATION DEVELOPING FROM WEST TO EAST OVERNIGHT AND TOMORROW
MORNING. LOOK FOR IFR CIGS THE NEXT 24 HRS ACROSS THE MID STATE
WITH WINDS INCREASING DRAMATICALLY AS THE SFC LOW EDGES CLOSER TO
MIDDLE TENNESSEE.
&&
.PRELIMINARY POINT TEMPS/POPS...
NASHVILLE 35 38 26 33 15 / 100 100 70 20 0
CLARKSVILLE 32 32 24 31 14 / 90 100 50 20 0
CROSSVILLE 35 39 24 29 15 / 100 100 80 30 10
COLUMBIA 38 41 25 32 18 / 100 100 60 20 0
LAWRENCEBURG 39 42 26 32 20 / 100 100 70 20 0
WAVERLY 33 34 24 32 17 / 100 100 50 10 0
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING FROM 6 AM FRIDAY TO 6 AM CST SATURDAY FOR
CANNON-CHEATHAM-CLAY-CUMBERLAND-DAVIDSON-DE KALB-DICKSON-
FENTRESS-HICKMAN-HOUSTON-HUMPHREYS-JACKSON-LEWIS-MACON-MAURY-
MONTGOMERY-OVERTON-PERRY-PICKETT-PUTNAM-ROBERTSON-RUTHERFORD-
SMITH-STEWART-SUMNER-TROUSDALE-WHITE-WILLIAMSON-WILSON.
WINTER STORM WATCH FROM FRIDAY MORNING THROUGH LATE FRIDAY NIGHT
FOR BEDFORD-COFFEE-GILES-GRUNDY-LAWRENCE-MARSHALL-VAN BUREN-
WARREN-WAYNE.
&&
$$
SHORT TERM/AVIATION........08
LONG TERM..................19
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1103 AM CST THU JAN 21 2016
.UPDATE...
FOR 18Z AVIATION DISCUSSION.
&&
.DISCUSSION...
DIFFICULT FORECAST FOR THE MID STATE TO FINISH OFF THE WEEK AS
ANOTHER ROUND OF WINTER PRECIP WILL MOVE INTO THE AREA. BEFORE
THAT...WE HAVE SOME FOG DEVELOPING THIS MORNING THANKS TO HIGHER
SURFACE MOISTURE FROM THE LAST ROUND OF PRECIP YESTERDAY. WHILE
ISOLATED...FREEZING FOG ADVISORY GOES THROUGH 15Z...AND WILL LET
THAT RUN THROUGH. FOG SHOULD START TO DISSIPATE MID MORNING AS
TEMPERATURES SLOWLY RISE.
CHANCES FOR RAIN WILL MOVE IN FROM THE SOUTH TODAY AHEAD OF THE
NEXT TROUGH. INTERESTING FEATURE WITH THE INITIAL ONSET OF RAIN IS
THE CHANCE FOR SOME RUMBLES OF THUNDER AS WELL. MODEL SOUNDINGS
ARE SHOWING SOME ELEVATED INSTABILITY THIS AFTERNOON ALL THE WAY
INTO THE EARLY MORNING HOURS ON FRIDAY. KEPT IN MENTION OF THUNDER
FROM THE PREVIOUS FORECAST BECAUSE OF THIS.
THINGS START GETTING VERY INTERESTING FRIDAY AS THE UPPER LOW
TRACKS OVER THE REGION FROM THE SOUTHWEST. TIMING OF THE ONSET OF
FROZEN PRECIPITATION REMAINS DIFFICULT AS WELL AS PRECIP TYPES TO
EXPECT BETWEEN THE TRANSITION FROM RAIN TO SNOW. MODEL SOUNDINGS
ARE INDICATING THAT THERE WILL BE SOME SLEET AND FREEZING RAIN
POSSIBLE FOR THE TRANSITION ZONE. THERE LOOKS TO BE A PRETTY
SUBSTANTIAL WARM NOSE BELOW 850MB THAT IS ABOUT 4C DURING THE
EARLY MORNING HOURS ON FRIDAY. THE DEPTH OF THE WARM AIR LOOKS TO
BE BETWEEN 1000-2000 FT DEPENDING ON THE MODEL...SO THAT SHOULD BE
ENOUGH TO MELT FALLING SNOW INTO EITHER SLEET OR FREEZING RAIN AS
THE SURFACE COOLS. FOR NOW HAVE A PRETTY BROAD MIX OF
PRECIPITATION TYPES STARTING IN THE NORTHWEST AFTER 09Z...INTO THE
NASHVILLE AREA BY 15Z...AND ALL SNOW FOR THE CWA BY 00Z. IT WILL
BE POSSIBLE FOR HIGHER ELEVATIONS OUT ON THE PLATEAU TO SWITCH
OVER TO MIXED PRECIP AND SNOW A BIT EARLIER THAN AREAS TO THE
WEST...BUT FOR THE MOST PART THE AREA SHOULD BE ALL SNOW AFTER 00Z
SATURDAY.
AS FOR ACCUMULATIONS OF SNOW AND ICE...CURRENTLY HAVE A TENTH OR
LESS OF ICE ACCUMULATION MAINLY IN AREAS NEAR THE KY BORDER. WPC
SHOWS A 50 PERCENT CHANCE OF A TENTH OF AN INCH OF ICE FOR THAT
AREA...SO WILL CONTINUE WITH THE CURRENT FORECAST AMOUNTS. THOSE
AMOUNTS MAY NEED TO BE ADJUSTED OBVIOUSLY....SHOULD THE ONSET OF
FROZEN PRECIP MOVE IN EARLIER OR THE MIXED PRECIP LAST A BIT
LONGER INTO THE MORNING HOURS FRIDAY. SNOW AMOUNTS HAVEN`T CHANGED
TOO MUCH FROM THE PREVIOUS FORECAST...WITH THE HIGHER AMOUNTS IN
THE NORTHWEST AND LOWER AMOUNTS IN THE SOUTH NEAR THE AL BORDER.
MODEL CONSENSUS LOOKS TO BE A BIT HIGHER IN REGARDS TO AMOUNTS FOR
THE AREA...BUT WITH ALL OF THE RAIN AND MIXED PRECIP THE AREA WILL
SEE BEFOREHAND...SNOW AMOUNTS MAY BE A BIT LESS. THE EARLY ONSET
OF SNOW MAY MELT BEFORE ACCUMULATIONS CAN REALLY GET GOING.
FOR THE REST OF THE FORECAST...A BRIEF DRY PERIOD MOVES IN TO
FINISH OFF THE WEEKEND AND START THE NEXT WORK WEEK BEFORE ANOTHER
SHOT AT PRECIP MOVES IN LATER ON MONDAY. RIDGING TRIES TO MOVE IN
ON WEDNESDAY AND FOR THE REMAINDER OF THE WEEK...SO KEPT THE
REST OF THE LONG TERM FORECAST DRY.
&&
.AVIATION...
18Z TAF DISCUSSION.
BNA/CKV/CSV...MOISTURE CONTINUES TO ADVECT NE`WD INTO MIDDLE
TENNESSEE AS A SURFACE LOW TRACKS FROM THE GULF COAST TOWARD THE
TENNESSEE VALLEY. HRRR SHOWS RAIN MOVING INTO MIDDLE TENNESSEE
THIS AFTERNOON, REACHING BNA & CKV AROUND 23Z, THEN THE PLATEAU
DURING THE EVENING. AS THE LOW CONTINUES TO MOVE TOWARD THE E/NE,
WINDS WILL TURN MORE NE`WD WITH FALLING TEMPERATURES AND WINTRY
PRECIPITATION DEVELOPING FROM WEST TO EAST OVERNIGHT AND TOMORROW
MORNING. LOOK FOR IFR CIGS THE NEXT 24 HRS ACROSS THE MID STATE
WITH WINDS INCREASING DRAMATICALLY AS THE SFC LOW EDGES CLOSER TO
MIDDLE TENNESSEE.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING FROM 6 AM FRIDAY TO 6 AM CST SATURDAY FOR
CANNON-CHEATHAM-CLAY-CUMBERLAND-DAVIDSON-DE KALB-DICKSON-
FENTRESS-HICKMAN-HOUSTON-HUMPHREYS-JACKSON-LEWIS-MACON-MAURY-
MONTGOMERY-OVERTON-PERRY-PICKETT-PUTNAM-ROBERTSON-RUTHERFORD-
SMITH-STEWART-SUMNER-TROUSDALE-WHITE-WILLIAMSON-WILSON.
WINTER STORM WATCH FROM FRIDAY MORNING THROUGH LATE FRIDAY NIGHT
FOR BEDFORD-COFFEE-GILES-GRUNDY-LAWRENCE-MARSHALL-VAN BUREN-
WARREN-WAYNE.
&&
$$
SHORT TERM/AVIATION........08
LONG TERM..................19