Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 12/23/13
AREA FORECAST DISCUSSION
NWS PUEBLO CO
250 PM MST SAT DEC 21 2013
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 250 PM MST SAT DEC 21 2013
UPPER LOW IS LIFTING OUT INTO WESTERN OK WHILE TRAILING ENERGY IS
DROPPING ACROSS THE FORECAST AREA IN NW FLOW ALOFT. PRECIPITATION HAS
BEEN SLOW TO GET GOING ACROSS THE FORECAST AREA...THOUGH WEB CAMS
AND SURFACE OBS ALONG THE CONTDVD HAVE BEEN REPORTING SOME SNOW
THROUGH THE DAY. INITIALLY HEAVIEST SNOW AND BEST LIFT WILL BE OUT
ACROSS THE FAR SOUTHEAST CORNER OF THE FORECAST AREA WHERE WRAP
AROUND PRECIPITATION CONTINUES ACROSS BACA COUNTY. STILL SOME
VARIABILITY IN THE SHORT RANGE MODELS FOR SNOW AMOUNTS OUT THAT
WAY...BUT AN INCH OR TWO WOULD`T BE OUT OF THE QUESTION ACROSS
SOUTHEAST PORTIONS OF BACA COUNTY. MEANWHILE...SHOULD START TO SEE
LIGHT SNOW RAMP UP ACROSS THE EASTERN MOUNTAINS AND ADJACENT PLAINS
BY 4 PM...WHICH WILL SPREAD SOUTH AND EAST THROUGH THE EVENING.
NAM12 AND HRRR SEEM TO BE BACKING OFF ON SNOWFALL AMOUNTS WITH EACH
RUN...WITH NAM12 NOW SHOWING AROUND 2-4 INCHES FOR THE SE MTS. HAVE
KEPT SNOW AMOUNTS IN THE 2-6 INCH RANGE AS SUSPECT THERE WILL BE POCKETS OF
HEAVIER AMOUNTS...HOWEVER WITHOUT A PERSISTENT DEEP NE UPSLOPE
FLOW...THINK THESE HEAVIER AMOUNTS WILL BE MORE LOCALIZED. THUS
ADVISORIES DO NOT SEEM WARRANTED AT THIS POINT. LIGHT SNOW WILL
WIND DOWN TOWARDS TOMORROW MORNING WITH PARTIAL CLEARING ACROSS
WESTERN AND NORTHERN PORTIONS OF THE AREA TOWARDS DAWN. THIS OPENS
UP THE POSSIBILITY FOR ANOTHER ROUND OF GROUND FOG AT KALS EARLY
SUNDAY MORNING...AND HAVE INTRODUCED THIS TO THE GRIDS.
QUIET WEATHER FOR SUNDAY...THOUGH NORTHWEST FLOW MAY KEEP SOME
SCATTERED OROGRAPHIC SNOW SHOWERS CONTINUING ACROSS THE CENTRAL MTS.
TEMPERATURES TOMORROW MAY END UP SIMILAR TO THOSE OF TODAY...PERHAPS
A LITTLE WARMER ACROSS PORTIONS OF THE PLAINS AND A TAD COOLER
ACROSS THE MTS WHERE H7 TEMPS WILL BE A LITTLE COOLER BEHIND THIS
EVENINGS SYSTEM. -KT
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 250 PM MST SAT DEC 21 2013
SUNDAY NIGHT-MONDAY...STRONG NORTH TO NORTHWEST FLOW ALOFT ACROSS
THE REGION SUNDAY NIGHT SLOWLY MODERATES THROUGH THE DAY MONDAY...AS
A BROAD UPPER TROUGH AND ASSOCIATED 120KT JET CORE ACROSS THE NORTHERN
ROCKIES TRANSLATES OUT ACROSS THE NORTHERN AND CENTRAL HIGH PLAINS.
NORTHWEST FLOW ALOFT BEHIND THE SYSTEM LOOKS TO KEEP GENERALLY LIGHT
SNOWFALL IN PLACE ACROSS THE CENTRAL MTS THROUGH EARLY MONDAY
MORNING...WITH ACCUMULATIONS OF A FEW INCHES POSSIBLE ESPECIALLY
NORTH OF COTTONWOOD PASS. PASSING SYSTEM STAYS TOO FAR NORTH AND
EAST TO BRING PRECIPITATION TO THE REST OF SOUTH CENTRAL AND
SOUTHEAST COLORADO...THOUGH DOES SEND A WEAK COLD FRONT ACROSS
THE FAR EASTERN PLAINS EARLY MONDAY MORNING...KEEPING THE COOLEST
TEMPERATURES OUT NEAR THE KANSAS BORDER.
MONDAY NIGHT-CHRISTMAS DAY...LATEST MODELS CONTINUE TO DOWNPLAY
SNOWFALL ACROSS THE AREA FOR CHRISTMAS EVE AND EARLY CHRISTMAS DAY
WITH MODERATE NORTHWEST FLOW ALOFT ACROSS THE STATE AS ANOTHER
UPPER TROUGH TRANSLATES ACROSS THE NORTHERN ROCKIES. THE 12Z ECMWF
IS STILL A TAD DEEPER WITH SAID SYSTEM AND CONTINUES TO PRINT OUT
SOME QPF ACROSS THE EASTERN MTS TUESDAY NIGHT...THOUGH WITH ITS H7
FLOW PROGGED TO REMAIN NORTH TO NORTHWEST...ANY SNOW WOULD GENERALLY
REMAIN SOUTH OF HIGHWAY 50 ACROSS THE SOUTHERN I-25 CORRIDOR. AT ANY
RATE...MODEL CONSENSUS KEEPS SLIGHT POPS ACROSS THE HIGHER TERRAIN
AS WELL AS ALONG THE PALMER DVD AND RATON MESA FOR LATE TUESDAY
AFTERNOON THROUGH EARLY WEDNESDAY MORNING AND HAVE STAYED THE COURSE
FOR NOW. AS FOR TEMPS...WESTERLY FLOW AHEAD OF SAID SYSTEM LOOKS TO
KEEP BREEZY WINDS AND WARMING TEMPERATURES ACROSS THE STATE MONDAY
NIGHT AND TUESDAY...WITH ANOTHER WEAK COLD FRONT MOVING ACROSS THE
PLAINS CHRISTMAS EVE HELPING TO COOL HIGHS TO NEAR SEASONAL AVERAGES
FOR CHRISTMAS DAY.
WEDNESDAY NIGHT-SATURDAY...MODERATE NORTHWEST FLOW PROGGED ACROSS
THE REGION THROUGH THE REST OF THE EXTENDED PERIOD WITH A FEW MINOR
DISTURBANCES MOVING THROUGH THE FLOW ACROSS THE NORTHERN ROCKIES AND
INTO THE NORTHERN HIGH PLAINS. THIS WILL KEEP THE AREA GENERALLY
WARM AND DRY...SAVE A FEW OCCASIONAL FLURRIES ACROSS THE HIGHER
TERRAIN OF THE CENTRAL MTS...AS TEMPERATURES WARM BACK TO ABOVE
SEASONAL LEVELS THROUGH THE PERIOD.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 250 PM MST SAT DEC 21 2013
SNOW SHOWERS WILL CONTINUE TO DEVELOP AND SPREAD TO THE SOUTHEAST
ACROSS THE AREA THROUGH THE LATE AFTERNOON AND EARLY EVENING. STILL
APPEARS THAT KCOS AND KALS MAY SEE PASSING -SHSN THIS EVENING...WITH
SOME BRIEF MVFR CIGS/VIS. LOWER CIGS/VIS WILL LIKELY OCCUR ACROSS
THE SE MTS...WITH IFR TO LIFR CONDITIONS AT TIMES. KPUB WILL HAVE
THE LEAST THREAT OF BEING IMPACTED BY SNOW...SO HAVE KEPT CIGS
PRIMARILY VFR. AS FOR SNOWFALL...SHOULD SEE LESS THAN AN INCH AT
THE KCOS AND KALS TERMINALS. -SHSN WILL TAPER OFF FROM NORTHWEST TO
SOUTHEAST OVERNIGHT...WITH IMPROVING CONDITIONS AT THE KCOS AND KPUB
TAF SITES. WITH CLEARING SKIES OVERNIGHT...KALS MAY SEE A RETURN OF
IFR TO LIFR CIGS/VIS WITH PATCHY GROUND FOG SUNDAY MORNING AND HAVE
PUT THIS IN THE TAF BETWEEN 12Z AND 16Z.
VFR CONDITIONS WILL RETURN FOR MOST OF THE REGION ON SUNDAY. THE
EXCEPTION WILL BE SOME MVFR TO IFR CIGS AT TIMES ACROSS THE
CENTRAL MOUNTAINS WHERE SCATTERED LIGHT OROGRAPHIC SNOW SHOWERS WILL
CONTINUE. -KT
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...KT
LONG TERM...MW
AVIATION...KT
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1238 PM MST SAT DEC 21 2013
.UPDATE...BASED ON LATEST RADAR TRENDS...BAND OF SNOW IS SHIFTING
SOUTHWARD AND AIRMASS IS SATURATING WITH LIGHT SNOW MOVING INTO
FORT COLLINS. THIS WILL CONTINUE TO SPREAD SOUTHWARD THROUGH THE
REST OF THE AFTERNOON...SO HAVE FURTHER INCREASED POPS IN/NEAR THE
FOOTHILLS. EARLIER ARRIVAL LOOKS LIKE AN EARLIER DEPARTURE AS
WELL...WITH MOST SNOW IN THE LOWER ELEVATIONS OVER BY MIDNIGHT.
&&
.AVIATION...MOVED UP TIMING OF SNOW BASED ON LATEST RADAR TRENDS.
SHOULD REACH KBJC BY 22Z AND KDEN BY 23Z-00Z.
&&
.PREV DISCUSSION... /ISSUED 1108 AM MST SAT DEC 21 2013/
UPDATE...BAND OF MID LEVEL MOISTURE AND LIGHT SNOW WAS CURRENTLY
SPREADING ACROSS THE MOUNTAINS AND FAR NORTHER BORDER AREA. MOST
OF THIS IS VIRGA ON THE PLAINS RIGHT NOW...BUT CONTINUED WEAK LIFT
AND WEAK ANTICYCLONIC UPSLOPE FLOW SHOULD EVENTUALLY SATURATE THE
LOWER LEVELS LATER THIS AFTERNOON INTO THE EVENING. GIVEN CURRENT
RADAR TRENDS AND SHORT RANGE MODEL GUIDANCE...HAVE INCREASED THE
AFTERNOON POPS IN/NEAR THE FOOTHILLS. LATEST RAP RUNS SEEM TO GET
A LITTLE TOO EXCITED ABOUT SNOW AMOUNTS AGAINST THE FRONT RANGE
THIS EVENING...BUT THERE IS SOME LOW/MID LEVEL INSTABILITY SO WILL
CONTINUE TO MONITOR POTENTIAL SNOW ACCUMULATIONS. AT THIS
TIME...STILL LOOKING LIKE MOST PLAINS LOCATIONS SHOULD BE AN INCH
OR LESS. IN THE MOUNTAINS...OROGRAPHIC HELP WILL LIKELY PROVIDE
LOW END ADVISORY AMOUNTS THROUGH SUNDAY MORNING.
AVIATION...FOG IS FINALLY LIFTING AT KDEN...ONE OF THE LAST
PLACES TO CLEAR. NEXT WEATHER CONCERN IS SNOW AS ECHOES ALREADY
FILLING IN NEAR THE WYOMING BORDER. THESE WILL ADVANCE SLOWLY
SOUTHWARD WITH A LOWERING OF THE CLOUD DECK AND EXPECTED ILS
LANDING CONDITIONS DEVELOPING BY 21Z-22Z. LATEST TRENDS SEEM TO BE
A LITTLE FASTER SO THERE IS ALSO A CHANCE OF LIGHT SNOW DEVELOPING
AS EARLY AS 22Z...BUT MAIN THREAT OF SNOW AND IFR CONDITIONS IS
00Z-08Z. ACCUMULATIONS AT THE FRONT RANGE AIRPORTS MOST LIKELY AN
INCH OR LESS...AND KDEN WILL LIKELY BE ON THE EDGE OF THE
ACCUMULATING SNOW.
PREV DISCUSSION... /ISSUED 824 AM MST SAT DEC 21 2013/
AVIATION...DENSE FOG AT KDEN WITH RVRS MAINLY BELOW 1000 FT. THE
FOG HAS LIFTED AT KBJC WITH ONLY LIGHT FOG AT KAPA...AND EROSION
SHOULD CONTINUE FROM THE WEST/WEST-SOUTHWEST AS SURFACE WINDS
ARE TRENDING THAT WAY. EXACT TIMING OF DISSIPATION AT KDEN IS
DIFFICULT DUE TO HIGH CLOUDS MOVING OVER THE TOP...BUT AT THIS
TIME EXPECT SOME IMPROVEMENT STARTING 16Z AND TOTAL EROSION
EXPECTED BY 17Z-18Z. WILL CONTINUE TO MONITOR.
PREV DISCUSSION... /ISSUED 528 AM MST SAT DEC 21 2013/
UPDATE...
SHORT TERM...AREAS OF DENSE FOG HAVE EXPANDED THE PAST HOUR SO
HAVE ISSUED AN ADVISORY BOUNDED BY A FORT COLLINS TO GREELEY TO
FORT MORGAN TO DENVER LINE.
AVIATION...WEAK DENVER CYCLONE WITH LIGHT NW WINDS HAS ALLOWED
DENSE FOG OVER WELD COUNTY TO EXPAND SOUTHWARD INTO THE DENVER
AREA. EXPECT THESE CONDITIONS WILL CONTINUE THROUGH 16Z.
PREV DISCUSSION... /ISSUED 330 AM MST SAT DEC 21 2013/
SHORT TERM...SOME LOCALIZED FOG EARLY THIS MORNING EXTENDED FM
FORT COLLINS TOWARDS FORT MORGAN AS SHOWN BY CIRA IMAGERY BUT
SHOULD BURN OFF BY MID MORNING. OVERALL WILL CONTINUE TO SEE NW
FLOW ALOFT THRU TONIGHT AS A FEW WEAK DISTURBANCES TRACK ACROSS
NRN CO MAINLY TONIGHT. CROSS-SECTIONS SHOW MOISTURE WILL INCREASE
IN THE MTNS BY THIS AFTN AND CONTINUE OVERNIGHT WITH FAVORABLE
OROGRAPHICS AND LAPSE RATES AROUND 7 C/KM. THUS SNOW SHOULD
INCREASE THIS AFTN AND CONTINUE OVERNIGHT SO WILL ISSUE A WINTER
WEATHER WINTER ADVISORY WHICH WILL LINGER THRU MIDDAY SUN.
OTHERWISE OVER NERN CO IT SHOULD BE DRY THRU THE AFTN ALTHOUGH
COULD SEE A FEW LIGHT SNOW SHOWERS DEVELOP NR THE WY BORDER AND
OVER THE PALMER DIVIDE LATE. HIGHS THIS AFTN WILL BE IN THE 30S
OVER THE PLAINS.
BY THIS EVENING A SURGE OF COOLER AIR WILL MOVE INTO NERN CO AND
ENHANCE UPSLOPE FLOW ALONG THE FRONT RANGE. CROSS-SECTIONS SHOW
INCREASING MOISTURE BEHIND THIS FNT AND AS WK DISTURBANCE MOVES
ACROSS THIS EVENING SHOULD SEE A PERIOD OF LIGHT SNOW MAINLY IN AND
NEAR THE FOOTHILLS. AT THIS TIME ACCUMULATIONS SHOULD BE ONLY AN
INCH OR TWO. BY LATE TONIGHT THE UPSLOPE FLOW WILL GRADUALLY WEAKEN
AFTER MIDNIGHT SO SNOW SHOULD GRADUALLY END BY 09Z OR SO.
LONG TERM...BLOCKING MULTI-LEVEL HIGH PRESSURE RIDGE PRESENTLY OFF
THE WEST COAST OF NORTH AMERICA SHOWS LITTLE SIGNS OF MOVEMENT
DURING THE UPCOMING WEEK ACCORDING TO SHORT AND MEDIUM RANGE MODELS.
AS A CONSEQUENCE COLORADO WILL REMAIN UNDER MODERATELY STRONG
NORTHWEST FLOW DURING THE TIME PERIOD. MODELS SHOW A SERIES OF
SUBTLE UNDULATIONS IN THIS FLOW ROUNDING THE TOP OF THE RIDGE AND
PASSING OVER COLORADO...THE FIRST EXITING THE AREA SUNDAY
MORNING...ANOTHER PASSING BY SUNDAY EVENING...AND YET ANOTHER
PASSING THROUGH TUESDAY AFTERNOON AND/OR EVENING. RELYING ON THE
MODELS TO RESOLVE THESE WEAK PERTABATIONS AND THEIR SPEED OF
MOTION IN THIS FAST FLOW IS ASKING FOR DISAPPOINTMENT. THE SUNDAY
EVENING SYSTEM APPEARS TO HAVE THE BEST POTENTIAL FOR PRODUCING
SNOWFALL IN THE HIGH COUNTRY AND FOR PARTS OF NORTHEAST COLORADO.
GFS IS THE MOST OPTIMISTIC OF THE MODELS WITH SNOW CHANCES ON THE
PLAINS. HOWEVER THE NAM...GFS...ECMWF AND CANADIAN MODELS ALL
INDICATE THE PRESENCE OF THIS WAVE OVER NORTHEAST COLORADO SUNDAY
EVENING AND AT LEAST MIMINAL AMOUNTS OF QPF ACROSS THE NORTHEAST
CORNER OF THE STATE. SURROUNDING WFOS CONCUR AND SO HAVE UPPED
POPS TO 30-40 PCT IN ZONES ACROSS THE NORTHEAST CORNER SUNDAY
EVENING. SHOULD THEN SEE PRECIP/SNOW CHANCES FALL OFF AFTER 07Z
WITH THE JET LEVEL FORCING ALOFT EXITING THE AREA. ANY SNOW
ACCUMULATION SHOULD BE MINIMAL. MEANWHILE MOUNTAINS AND HIGH
VALLEYS HAVE A REASONABLE CHANCE OF MEASURING SNOWFALL WITH THIS
SYSTEM. FOR NOW...WILL GO WITH 40-60 PCT POPS IN THE MTN ZONES
AND 30-40 PCT POPS IN NORTH AND MIDDLE PARKS...ZONE 30 AND 32. SEE
LITTLE IF ANY CHANCE OF SNOW FOR SOUTH PARK ZONE 37 AS NORTHWEST
FLOW NOT CONDUCIVE FOR SNOWFALL HERE. COULD SEE A COUPLE INCHES
OF SNOW ON THE NORTHERN MTN RIDGES AND HIGH PASSES BY MONDAY
MORNING. NOT EXPECTING ANY SNOW IN THE I-25 URBAN CORRIDOR...
EXCEPT PERHAPS A DUSTING UP NEAR THE WYOMING BORDER.
THE LAST OF THESE WAVES IS PREDICTED BY THE EUROPEAN MODEL TO
PASS OVER NORTHEAST COLORADO TUESDAY EVENING. WHEREAS THE GFS
MODEL BARELY SHOWS A WAVE AND HARDLY ANY MOISTURE. HOWEVER...BOTH
MODELS SHOW A WEAK COLD FRONT SLIPPING SOUTH ACROSS NORTHEAST
COLORADO DURING THE AFTERNOON USHERING IN COLDER TEMPERATURES FOR
TUESDAY NIGHT AND WEDNESDAY/CHRISTMAS DAY. SO FOR NOW...WILL HANG
ONTO LOW POPS FOR TUESDAY EVENING IN THE MTNS...FOOTHILLS AND
ALONG THE PALMER DIVIDE JUST IN CASE THE ECMWF IS CORRECT.
WEDNESDAY AND BEYOND...A DRY AND COOL NORTHWEST FLOW REMAINS IN
PLACE THROUGH THE END OF THE WEEK WITH A UPPER RIDGE STILL OFF
THE WEST COAST. MODELS HINT AT THE PASSAGE OF YET ANOTHER SHORT
WAVE DISTURBANCE EITHER THURSDAY AFTERNOON OR NIGHT. BUT
CONFIDENCE IS LOW IN THE MODELS THAT FAR OUT. SO WILL KEEP THINGS
DRY AND TEMPERATURES NEAR TO SLIGHTLY ABOVE AVERAGE THURSDAY AND
FRIDAY.
AVIATION...WINDS WERE SE EARLY THIS MORNING WITH CIRA IMAGERY
SHOWING FOG CONFINED TO AREAS AROUND FORT COLLINS TO GREELEY. THE
HRRR KEEPS THIS FOG AND LOW CLOUDS OVER WELD COUNTY THROUGH THE
MORNING HOURS. HOWEVER THE RAP SHOWS A WEAK DENVER CYCLONE
DEVELOPING WITH WINDS BECOMING LIGHT NNW BY SUNRISE WITH THE
POTENTIAL FOR FOG AND LOW CLOUDS WHICH WOULD LINGER THRU THE LATE
MORNING HOURS OVER DIA. AT THIS POINT WILL HAVE TO MONITOR TRENDS
THE NEXT FEW HOURS AND SEE HOW THINGS DEVELOP.
FOR TONIGHT A SURGE OF COOLER AIR WILL AFFECT THE AREA BEHIND A FNT
WITH UPSLOPE FLOW DEVELOPING. AT THIS TIME MAY SEE A PERIOD OF
LIGHT SNOW ESPECIALLY IN THE 02Z-08Z TIMEFRAME WITH UP TO AN INCH OF
ACCUMULATION POSSIBLE. THE SNOW THREAT SHOULD END BY 09Z OR SO WITH
IMPROVING CONDITIONS.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL NOON MST SUNDAY FOR COZ031-033-034.
&&
$$
SHORT TERM...BARJENBRUCH
LONG TERM....BAKER
AVIATION...BARJENBRUCH
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1108 AM MST SAT DEC 21 2013
.UPDATE...BAND OF MID LEVEL MOISTURE AND LIGHT SNOW WAS CURRENTLY
SPREADING ACROSS THE MOUNTAINS AND FAR NORTHER BORDER AREA. MOST
OF THIS IS VIRGA ON THE PLAINS RIGHT NOW...BUT CONTINUED WEAK LIFT
AND WEAK ANTICYCLONIC UPSLOPE FLOW SHOULD EVENTUALLY SATURATE THE
LOWER LEVELS LATER THIS AFTERNOON INTO THE EVENING. GIVEN CURRENT
RADAR TRENDS AND SHORT RANGE MODEL GUIDANCE...HAVE INCREASED THE
AFTERNOON POPS IN/NEAR THE FOOTHILLS. LATEST RAP RUNS SEEM TO GET
A LITTLE TOO EXCITED ABOUT SNOW AMOUNTS AGAINST THE FRONT RANGE
THIS EVENING...BUT THERE IS SOME LOW/MID LEVEL INSTABILITY SO WILL
CONTINUE TO MONITOR POTENTIAL SNOW ACCUMULATIONS. AT THIS
TIME...STILL LOOKING LIKE MOST PLAINS LOCATIONS SHOULD BE AN INCH
OR LESS. IN THE MOUNTAINS...OROGRAPHIC HELP WILL LIKELY PROVIDE
LOW END ADVISORY AMOUNTS THROUGH SUNDAY MORNING.
&&
.AVIATION...FOG IS FINALLY LIFTING AT KDEN...ONE OF THE LAST
PLACES TO CLEAR. NEXT WEATHER CONCERN IS SNOW AS ECHOES ALREADY
FILLING IN NEAR THE WYOMING BORDER. THESE WILL ADVANCE SLOWLY
SOUTHWARD WITH A LOWERING OF THE CLOUD DECK AND EXPECTED ILS
LANDING CONDITIONS DEVELOPING BY 21Z-22Z. LATEST TRENDS SEEM TO BE
A LITTLE FASTER SO THERE IS ALSO A CHANCE OF LIGHT SNOW DEVELOPING
AS EARLY AS 22Z...BUT MAIN THREAT OF SNOW AND IFR CONDITIONS IS
00Z-08Z. ACCUMULATIONS AT THE FRONT RANGE AIRPORTS MOST LIKELY AN
INCH OR LESS...AND KDEN WILL LIKELY BE ON THE EDGE OF THE
ACCUMULATING SNOW.
&&
.PREV DISCUSSION... /ISSUED 824 AM MST SAT DEC 21 2013/
AVIATION...DENSE FOG AT KDEN WITH RVRS MAINLY BELOW 1000 FT. THE
FOG HAS LIFTED AT KBJC WITH ONLY LIGHT FOG AT KAPA...AND EROSION
SHOULD CONTINUE FROM THE WEST/WEST-SOUTHWEST AS SURFACE WINDS
ARE TRENDING THAT WAY. EXACT TIMING OF DISSIPATION AT KDEN IS
DIFFICULT DUE TO HIGH CLOUDS MOVING OVER THE TOP...BUT AT THIS
TIME EXPECT SOME IMPROVEMENT STARTING 16Z AND TOTAL EROSION
EXPECTED BY 17Z-18Z. WILL CONTINUE TO MONITOR.
PREV DISCUSSION... /ISSUED 528 AM MST SAT DEC 21 2013/
UPDATE...
SHORT TERM...AREAS OF DENSE FOG HAVE EXPANDED THE PAST HOUR SO
HAVE ISSUED AN ADVISORY BOUNDED BY A FORT COLLINS TO GREELEY TO
FORT MORGAN TO DENVER LINE.
AVIATION...WEAK DENVER CYCLONE WITH LIGHT NW WINDS HAS ALLOWED
DENSE FOG OVER WELD COUNTY TO EXPAND SOUTHWARD INTO THE DENVER
AREA. EXPECT THESE CONDITIONS WILL CONTINUE THROUGH 16Z.
PREV DISCUSSION... /ISSUED 330 AM MST SAT DEC 21 2013/
SHORT TERM...SOME LOCALIZED FOG EARLY THIS MORNING EXTENDED FM
FORT COLLINS TOWARDS FORT MORGAN AS SHOWN BY CIRA IMAGERY BUT
SHOULD BURN OFF BY MID MORNING. OVERALL WILL CONTINUE TO SEE NW
FLOW ALOFT THRU TONIGHT AS A FEW WEAK DISTURBANCES TRACK ACROSS
NRN CO MAINLY TONIGHT. CROSS-SECTIONS SHOW MOISTURE WILL INCREASE
IN THE MTNS BY THIS AFTN AND CONTINUE OVERNIGHT WITH FAVORABLE
OROGRAPHICS AND LAPSE RATES AROUND 7 C/KM. THUS SNOW SHOULD
INCREASE THIS AFTN AND CONTINUE OVERNIGHT SO WILL ISSUE A WINTER
WEATHER WINTER ADVISORY WHICH WILL LINGER THRU MIDDAY SUN.
OTHERWISE OVER NERN CO IT SHOULD BE DRY THRU THE AFTN ALTHOUGH
COULD SEE A FEW LIGHT SNOW SHOWERS DEVELOP NR THE WY BORDER AND
OVER THE PALMER DIVIDE LATE. HIGHS THIS AFTN WILL BE IN THE 30S
OVER THE PLAINS.
BY THIS EVENING A SURGE OF COOLER AIR WILL MOVE INTO NERN CO AND
ENHANCE UPSLOPE FLOW ALONG THE FRONT RANGE. CROSS-SECTIONS SHOW
INCREASING MOISTURE BEHIND THIS FNT AND AS WK DISTURBANCE MOVES
ACROSS THIS EVENING SHOULD SEE A PERIOD OF LIGHT SNOW MAINLY IN AND
NEAR THE FOOTHILLS. AT THIS TIME ACCUMULATIONS SHOULD BE ONLY AN
INCH OR TWO. BY LATE TONIGHT THE UPSLOPE FLOW WILL GRADUALLY WEAKEN
AFTER MIDNIGHT SO SNOW SHOULD GRADUALLY END BY 09Z OR SO.
LONG TERM...BLOCKING MULTI-LEVEL HIGH PRESSURE RIDGE PRESENTLY OFF
THE WEST COAST OF NORTH AMERICA SHOWS LITTLE SIGNS OF MOVEMENT
DURING THE UPCOMING WEEK ACCORDING TO SHORT AND MEDIUM RANGE MODELS.
AS A CONSEQUENCE COLORADO WILL REMAIN UNDER MODERATELY STRONG
NORTHWEST FLOW DURING THE TIME PERIOD. MODELS SHOW A SERIES OF
SUBTLE UNDULATIONS IN THIS FLOW ROUNDING THE TOP OF THE RIDGE AND
PASSING OVER COLORADO...THE FIRST EXITING THE AREA SUNDAY
MORNING...ANOTHER PASSING BY SUNDAY EVENING...AND YET ANOTHER
PASSING THROUGH TUESDAY AFTERNOON AND/OR EVENING. RELYING ON THE
MODELS TO RESOLVE THESE WEAK PERTABATIONS AND THEIR SPEED OF
MOTION IN THIS FAST FLOW IS ASKING FOR DISAPPOINTMENT. THE SUNDAY
EVENING SYSTEM APPEARS TO HAVE THE BEST POTENTIAL FOR PRODUCING
SNOWFALL IN THE HIGH COUNTRY AND FOR PARTS OF NORTHEAST COLORADO.
GFS IS THE MOST OPTIMISTIC OF THE MODELS WITH SNOW CHANCES ON THE
PLAINS. HOWEVER THE NAM...GFS...ECMWF AND CANADIAN MODELS ALL
INDICATE THE PRESENCE OF THIS WAVE OVER NORTHEAST COLORADO SUNDAY
EVENING AND AT LEAST MIMINAL AMOUNTS OF QPF ACROSS THE NORTHEAST
CORNER OF THE STATE. SURROUNDING WFOS CONCUR AND SO HAVE UPPED
POPS TO 30-40 PCT IN ZONES ACROSS THE NORTHEAST CORNER SUNDAY
EVENING. SHOULD THEN SEE PRECIP/SNOW CHANCES FALL OFF AFTER 07Z
WITH THE JET LEVEL FORCING ALOFT EXITING THE AREA. ANY SNOW
ACCUMULATION SHOULD BE MINIMAL. MEANWHILE MOUNTAINS AND HIGH
VALLEYS HAVE A REASONABLE CHANCE OF MEASURING SNOWFALL WITH THIS
SYSTEM. FOR NOW...WILL GO WITH 40-60 PCT POPS IN THE MTN ZONES
AND 30-40 PCT POPS IN NORTH AND MIDDLE PARKS...ZONE 30 AND 32. SEE
LITTLE IF ANY CHANCE OF SNOW FOR SOUTH PARK ZONE 37 AS NORTHWEST
FLOW NOT CONDUCIVE FOR SNOWFALL HERE. COULD SEE A COUPLE INCHES
OF SNOW ON THE NORTHERN MTN RIDGES AND HIGH PASSES BY MONDAY
MORNING. NOT EXPECTING ANY SNOW IN THE I-25 URBAN CORRIDOR...
EXCEPT PERHAPS A DUSTING UP NEAR THE WYOMING BORDER.
THE LAST OF THESE WAVES IS PREDICTED BY THE EUROPEAN MODEL TO
PASS OVER NORTHEAST COLORADO TUESDAY EVENING. WHEREAS THE GFS
MODEL BARELY SHOWS A WAVE AND HARDLY ANY MOISTURE. HOWEVER...BOTH
MODELS SHOW A WEAK COLD FRONT SLIPPING SOUTH ACROSS NORTHEAST
COLORADO DURING THE AFTERNOON USHERING IN COLDER TEMPERATURES FOR
TUESDAY NIGHT AND WEDNESDAY/CHRISTMAS DAY. SO FOR NOW...WILL HANG
ONTO LOW POPS FOR TUESDAY EVENING IN THE MTNS...FOOTHILLS AND
ALONG THE PALMER DIVIDE JUST IN CASE THE ECMWF IS CORRECT.
WEDNESDAY AND BEYOND...A DRY AND COOL NORTHWEST FLOW REMAINS IN
PLACE THROUGH THE END OF THE WEEK WITH A UPPER RIDGE STILL OFF
THE WEST COAST. MODELS HINT AT THE PASSAGE OF YET ANOTHER SHORT
WAVE DISTURBANCE EITHER THURSDAY AFTERNOON OR NIGHT. BUT
CONFIDENCE IS LOW IN THE MODELS THAT FAR OUT. SO WILL KEEP THINGS
DRY AND TEMPERATURES NEAR TO SLIGHTLY ABOVE AVERAGE THURSDAY AND
FRIDAY.
AVIATION...WINDS WERE SE EARLY THIS MORNING WITH CIRA IMAGERY
SHOWING FOG CONFINED TO AREAS AROUND FORT COLLINS TO GREELEY. THE
HRRR KEEPS THIS FOG AND LOW CLOUDS OVER WELD COUNTY THROUGH THE
MORNING HOURS. HOWEVER THE RAP SHOWS A WEAK DENVER CYCLONE
DEVELOPING WITH WINDS BECOMING LIGHT NNW BY SUNRISE WITH THE
POTENTIAL FOR FOG AND LOW CLOUDS WHICH WOULD LINGER THRU THE LATE
MORNING HOURS OVER DIA. AT THIS POINT WILL HAVE TO MONITOR TRENDS
THE NEXT FEW HOURS AND SEE HOW THINGS DEVELOP.
FOR TONIGHT A SURGE OF COOLER AIR WILL AFFECT THE AREA BEHIND A FNT
WITH UPSLOPE FLOW DEVELOPING. AT THIS TIME MAY SEE A PERIOD OF
LIGHT SNOW ESPECIALLY IN THE 02Z-08Z TIMEFRAME WITH UP TO AN INCH OF
ACCUMULATION POSSIBLE. THE SNOW THREAT SHOULD END BY 09Z OR SO WITH
IMPROVING CONDITIONS.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL NOON MST SUNDAY FOR COZ031-033-034.
&&
$$
SHORT TERM...BARJENBRUCH
LONG TERM....BAKER
AVIATION...BARJENBRUCH
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1042 AM MST SAT DEC 21 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 319 AM MST SAT DEC 21 2013
...SOME SNOW FOR THE MOUNTAINS THROUGH THIS EVENING...
MAIN FORECAST CHALLENGE TODAY IS STILL THE EXTENT OF LOW CLOUDS
AND FOG OVER THE PLAINS AND VALLEYS. A STUBBORN PATCH OF STRATUS AND
FOG HAS HUNG ON OVER NRN PUEBLO...SRN EL PASO...AND CROWLEY COUNTIES
AND AS OF 230 AM STILL SHOWS NO SIGNS OF DISSIPATING AS WINDS REMAIN
VERY LIGHT. GUIDANCE IS AGAIN NOT VERY HELPFUL...WITH NONE OF THE
HIGH RES MODELS SHOWING ANY FOG DESPITE THE CURRENT CONDITIONS. THE
RAP SOUNDING HAD FOG AT KCOS...BUT DISSIPATING QUICKLY AFTER
09Z...WHICH OBVIOUSLY IS NOT HAPPENING. THE SAN LUIS VALLEY ALSO
PROBLEMATIC...AS SOME GUIDANCE...LIKE THE NAM...SHOWING SATURATED
LOW LEVELS PERSISTING THROUGH THE DAY...WHILE THE RAP IS MUCH MORE
OPTIMISTIC. HIGH RES WRF LOOKS LIKE A REASONABLE COMPROMISE FOR THE
VALLEY...KEEPING THE LOW CLOUDS AROUND THROUGH MID MORNING...THEN
INCREASING CLOUDS LATER TODAY AS THE NRN BRANCH SHORTWAVE SWINGS
THROUGH OUR AREA. WILL STAY ON THE PESSIMISTIC SIDE OF THE FORECAST
AND KEEP THE AREA CLOUDY WITH TEMPS ON THE LOW SIDE OF GUIDANCE...OR
20S FOR THE MTS AND HIGH VALLEYS AND 30S FOR THE PLAINS.
BEST CHANCE OF SNOW FOR MOST OF THE AREA STILL LOOKS TO BE LATE THIS
AFTERNOON THROUGH THIS EVE AS THE WAVE MOVES ACROSS. EXPECT THE BEST
ACCUMS TO COME OVER THE HYR ELEVATIONS OF THE SANGRES..WETS...AND
RAMPARTS. COULD SEE LOW END ADVISORY AMTS ABOVE 10000 FEET...IN THE
3 TO 6 INCH RANGE...BUT IMPACT SHOULD BE MINIMAL SO WILL HOLD OFF
FROM ANY HEADLINES FOR NOW. MAY HAVE TO REEVALUATE IF 12Z RUNS SHOW
AN UPWARD TREND. ONGOING LOW POPS FOR THE I-25 CORRIDOR THIS EVENING
LOOK ON TARGET...BUT NOT EXPECTING MUCH IF ANY ACCUMULATION. PRECIP
SHOULD WIND DOWN AFTER MIDNIGHT TONIGHT...AND IT WILL BE ANOTHER
COLD NIGHT WITH TEMPS IN THE SINGLE DIGITS AND TEENS FOR THE MTS
AND PLAINS RESPECTIVELY. ROSE
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 319 AM MST SAT DEC 21 2013
BY THE BEGINNING OF THIS PERIOD (12Z SUNDAY)...SHORTWAVE TROUGH IN
THE NW FLOW ALOFT WILL BE EXITING THE REGION. A FEW SNOW SHOWERS
WILL BE POSSIBLE EARLY IN THE DAY ACROSS THE PIKES PEAK REGION AND
S MTNS...BUT SHOULD END BY NOON. SNOW SHOWERS WILL CONTINUE ACROSS
THE C MTNS (NW SLOPES) THROUGHOUT THE DAY.
SUNDAY NIGHT ANOTHER WEAK WAVE WILL MOVE SOUTHEAST IN THE NW FLOW
ALOFT. THIS WILL KEEP SNOW SHOWERS ONGOING OVER THE C MTNS. SOME
SNOW SHOWERS WILL ALSO BE POSSIBLE IN NE COLO AND WILL TRACK
SOUTHEAST...BUT THESE SNOW SHOWERS SHOULD STAY OUT OF THE NWS PUB
CWA.
MONDAY INTO EARLY TUESDAY...WEAK RIDGING ALOFT WILL OCCUR...AND THIS
SHOULD BRING PARTLY CLOUDY SKIES TO THE REGION. HOWEVER WE MAY SEE
SOME WAVE CLOUDS ALONG THE GREATER I-25 CORRIDOR REGION DURING THIS
PD. TEMPS SHOULD BE AOA SEASONABLE VALUES MON AND TUE.
LATER ON TUESDAY ANOTHER COOL FRONT WILL MOVE ACROSS THE REGION LATE
IN THE DAY. THE 00Z GFS WAS DRY WITH THIS SYSTEM WHILE THE EC
CONTINUES TO BE A BIT STRONGER...AND BREAKS OUT SOME LIGHT PRECIP
OVER THE GREATER S MTN REGION XMAS EVE INTO EARLY XMAS DAY. FOR THIS
REASON I KEPT SOME SLIGHT POPS FOR THE PIKES PEAK REGION AND S
MTNS/RATON MESA REGION.
FOR THE REST OF THE PD...NW FLOW ALOFT CONTINUES WITH ANOTHER WEAK
SHORT WAVE MOVING ACROSS THE REGION THU AFTERNOON. THIS WAVE WILL
LIKELY BE DRY WITH A WEAK SURGE MOVING ACROSS THE PLAINS DURING THE
DAY THU. /HODANISH
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1010 AM MST SAT DEC 21 2013
A WEATHER SYSTEM WILL MOVE THROUGH THE REGION THIS EVENING
SPREADING A QUICK ROUND OF SNOW IN AND NEAR THE MOUNTAINS BETWEEN
20Z AND 12Z. KALS AND KCOS WILL SEE THE BEST CHANCE OF
EXPERIENCING SOME -SHSN...THOUGH ANY ACCUMULATIONS AT THE
TERMINALS WILL LIKELY STAY BELOW AN INCH. CIGS/VIS MAY BRIEFLY DROP
INTO THE MVFR CATEGORY WITH -SHSN...WITH LOWER CIGS/VIS OVER/NEAR
THE MOUNTAINS. CLEARING CONDITIONS WILL TAKE PLACE FROM NW TO SE
AFTER 06Z. GUIDANCE AND BUFKIT MODEL SOUNDINGS SUGGEST KALS WILL
GO DOWN IN FOG AGAIN SUNDAY MORNING BEHIND THE SYSTEM ONCE CLEARING
TAKES PLACE.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...ROSE
LONG TERM...HODANISH
AVIATION...KT
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
824 AM MST SAT DEC 21 2013
.AVIATION...DENSE FOG AT KDEN WITH RVRS MAINLY BELOW 1000 FT. THE
FOG HAS LIFTED AT KBJC WITH ONLY LIGHT FOG AT KAPA...AND EROSION
SHOULD CONTINUE FROM THE WEST/WEST-SOUTHWEST AS SURFACE WINDS
ARE TRENDING THAT WAY. EXACT TIMING OF DISSIPATION AT KDEN IS
DIFFICULT DUE TO HIGH CLOUDS MOVING OVER THE TOP...BUT AT THIS
TIME EXPECT SOME IMPROVEMENT STARTING 16Z AND TOTAL EROSION
EXPECTED BY 17Z-18Z. WILL CONTINUE TO MONITOR.
&&
.PREV DISCUSSION... /ISSUED 528 AM MST SAT DEC 21 2013/
UPDATE...
SHORT TERM...AREAS OF DENSE FOG HAVE EXPANDED THE PAST HOUR SO
HAVE ISSUED AN ADVISORY BOUNDED BY A FORT COLLINS TO GREELEY TO
FORT MORGAN TO DENVER LINE.
AVIATION...WEAK DENVER CYCLONE WITH LIGHT NW WINDS HAS ALLOWED
DENSE FOG OVER WELD COUNTY TO EXPAND SOUTHWARD INTO THE DENVER
AREA. EXPECT THESE CONDITIONS WILL CONTINUE THROUGH 16Z.
PREV DISCUSSION... /ISSUED 330 AM MST SAT DEC 21 2013/
SHORT TERM...SOME LOCALIZED FOG EARLY THIS MORNING EXTENDED FM
FORT COLLINS TOWARDS FORT MORGAN AS SHOWN BY CIRA IMAGERY BUT
SHOULD BURN OFF BY MID MORNING. OVERALL WILL CONTINUE TO SEE NW
FLOW ALOFT THRU TONIGHT AS A FEW WEAK DISTURBANCES TRACK ACROSS
NRN CO MAINLY TONIGHT. CROSS-SECTIONS SHOW MOISTURE WILL INCREASE
IN THE MTNS BY THIS AFTN AND CONTINUE OVERNIGHT WITH FAVORABLE
OROGRAPHICS AND LAPSE RATES AROUND 7 C/KM. THUS SNOW SHOULD
INCREASE THIS AFTN AND CONTINUE OVERNIGHT SO WILL ISSUE A WINTER
WEATHER WINTER ADVISORY WHICH WILL LINGER THRU MIDDAY SUN.
OTHERWISE OVER NERN CO IT SHOULD BE DRY THRU THE AFTN ALTHOUGH
COULD SEE A FEW LIGHT SNOW SHOWERS DEVELOP NR THE WY BORDER AND
OVER THE PALMER DIVIDE LATE. HIGHS THIS AFTN WILL BE IN THE 30S
OVER THE PLAINS.
BY THIS EVENING A SURGE OF COOLER AIR WILL MOVE INTO NERN CO AND
ENHANCE UPSLOPE FLOW ALONG THE FRONT RANGE. CROSS-SECTIONS SHOW
INCREASING MOISTURE BEHIND THIS FNT AND AS WK DISTURBANCE MOVES
ACROSS THIS EVENING SHOULD SEE A PERIOD OF LIGHT SNOW MAINLY IN AND
NEAR THE FOOTHILLS. AT THIS TIME ACCUMULATIONS SHOULD BE ONLY AN
INCH OR TWO. BY LATE TONIGHT THE UPSLOPE FLOW WILL GRADUALLY WEAKEN
AFTER MIDNIGHT SO SNOW SHOULD GRADUALLY END BY 09Z OR SO.
LONG TERM...BLOCKING MULTI-LEVEL HIGH PRESSURE RIDGE PRESENTLY OFF
THE WEST COAST OF NORTH AMERICA SHOWS LITTLE SIGNS OF MOVEMENT
DURING THE UPCOMING WEEK ACCORDING TO SHORT AND MEDIUM RANGE MODELS.
AS A CONSEQUENCE COLORADO WILL REMAIN UNDER MODERATELY STRONG
NORTHWEST FLOW DURING THE TIME PERIOD. MODELS SHOW A SERIES OF
SUBTLE UNDULATIONS IN THIS FLOW ROUNDING THE TOP OF THE RIDGE AND
PASSING OVER COLORADO...THE FIRST EXITING THE AREA SUNDAY
MORNING...ANOTHER PASSING BY SUNDAY EVENING...AND YET ANOTHER
PASSING THROUGH TUESDAY AFTERNOON AND/OR EVENING. RELYING ON THE
MODELS TO RESOLVE THESE WEAK PERTABATIONS AND THEIR SPEED OF
MOTION IN THIS FAST FLOW IS ASKING FOR DISAPPOINTMENT. THE SUNDAY
EVENING SYSTEM APPEARS TO HAVE THE BEST POTENTIAL FOR PRODUCING
SNOWFALL IN THE HIGH COUNTRY AND FOR PARTS OF NORTHEAST COLORADO.
GFS IS THE MOST OPTIMISTIC OF THE MODELS WITH SNOW CHANCES ON THE
PLAINS. HOWEVER THE NAM...GFS...ECMWF AND CANADIAN MODELS ALL
INDICATE THE PRESENCE OF THIS WAVE OVER NORTHEAST COLORADO SUNDAY
EVENING AND AT LEAST MIMINAL AMOUNTS OF QPF ACROSS THE NORTHEAST
CORNER OF THE STATE. SURROUNDING WFOS CONCUR AND SO HAVE UPPED
POPS TO 30-40 PCT IN ZONES ACROSS THE NORTHEAST CORNER SUNDAY
EVENING. SHOULD THEN SEE PRECIP/SNOW CHANCES FALL OFF AFTER 07Z
WITH THE JET LEVEL FORCING ALOFT EXITING THE AREA. ANY SNOW
ACCUMULATION SHOULD BE MINIMAL. MEANWHILE MOUNTAINS AND HIGH
VALLEYS HAVE A REASONABLE CHANCE OF MEASURING SNOWFALL WITH THIS
SYSTEM. FOR NOW...WILL GO WITH 40-60 PCT POPS IN THE MTN ZONES
AND 30-40 PCT POPS IN NORTH AND MIDDLE PARKS...ZONE 30 AND 32. SEE
LITTLE IF ANY CHANCE OF SNOW FOR SOUTH PARK ZONE 37 AS NORTHWEST
FLOW NOT CONDUCIVE FOR SNOWFALL HERE. COULD SEE A COUPLE INCHES
OF SNOW ON THE NORTHERN MTN RIDGES AND HIGH PASSES BY MONDAY
MORNING. NOT EXPECTING ANY SNOW IN THE I-25 URBAN CORRIDOR...
EXCEPT PERHAPS A DUSTING UP NEAR THE WYOMING BORDER.
THE LAST OF THESE WAVES IS PREDICTED BY THE EUROPEAN MODEL TO
PASS OVER NORTHEAST COLORADO TUESDAY EVENING. WHEREAS THE GFS
MODEL BARELY SHOWS A WAVE AND HARDLY ANY MOISTURE. HOWEVER...BOTH
MODELS SHOW A WEAK COLD FRONT SLIPPING SOUTH ACROSS NORTHEAST
COLORADO DURING THE AFTERNOON USHERING IN COLDER TEMPERATURES FOR
TUESDAY NIGHT AND WEDNESDAY/CHRISTMAS DAY. SO FOR NOW...WILL HANG
ONTO LOW POPS FOR TUESDAY EVENING IN THE MTNS...FOOTHILLS AND
ALONG THE PALMER DIVIDE JUST IN CASE THE ECMWF IS CORRECT.
WEDNESDAY AND BEYOND...A DRY AND COOL NORTHWEST FLOW REMAINS IN
PLACE THROUGH THE END OF THE WEEK WITH A UPPER RIDGE STILL OFF
THE WEST COAST. MODELS HINT AT THE PASSAGE OF YET ANOTHER SHORT
WAVE DISTURBANCE EITHER THURSDAY AFTERNOON OR NIGHT. BUT
CONFIDENCE IS LOW IN THE MODELS THAT FAR OUT. SO WILL KEEP THINGS
DRY AND TEMPERATURES NEAR TO SLIGHTLY ABOVE AVERAGE THURSDAY AND
FRIDAY.
AVIATION...WINDS WERE SE EARLY THIS MORNING WITH CIRA IMAGERY
SHOWING FOG CONFINED TO AREAS AROUND FORT COLLINS TO GREELEY. THE
HRRR KEEPS THIS FOG AND LOW CLOUDS OVER WELD COUNTY THROUGH THE
MORNING HOURS. HOWEVER THE RAP SHOWS A WEAK DENVER CYCLONE
DEVELOPING WITH WINDS BECOMING LIGHT NNW BY SUNRISE WITH THE
POTENTIAL FOR FOG AND LOW CLOUDS WHICH WOULD LINGER THRU THE LATE
MORNING HOURS OVER DIA. AT THIS POINT WILL HAVE TO MONITOR TRENDS
THE NEXT FEW HOURS AND SEE HOW THINGS DEVELOP.
FOR TONIGHT A SURGE OF COOLER AIR WILL AFFECT THE AREA BEHIND A FNT
WITH UPSLOPE FLOW DEVELOPING. AT THIS TIME MAY SEE A PERIOD OF
LIGHT SNOW ESPECIALLY IN THE 02Z-08Z TIMEFRAME WITH UP TO AN INCH OF
ACCUMULATION POSSIBLE. THE SNOW THREAT SHOULD END BY 09Z OR SO WITH
IMPROVING CONDITIONS.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 10 AM MST THIS MORNING FOR COZ038>040-
043>045.
WINTER WEATHER ADVISORY FROM NOON TODAY TO NOON MST SUNDAY FOR
COZ031-033-034.
&&
$$
SHORT TERM...RPK
LONG TERM....BAKER
AVIATION...BARJENBRUCH
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
528 AM MST SAT DEC 21 2013
.UPDATE...
&&
.SHORT TERM...AREAS OF DENSE FOG HAVE EXPANDED THE PAST HOUR SO
HAVE ISSUED AN ADVISORY BOUNDED BY A FORT COLLINS TO GREELEY TO
FORT MORGAN TO DENVER LINE.
.AVIATION...WEAK DENVER CYCLONE WITH LIGHT NW WINDS HAS ALLOWED
DENSE FOG OVER WELD COUNTY TO EXPAND SOUTHWARD INTO THE DENVER
AREA. EXPECT THESE CONDITIONS WILL CONTINUE THROUGH 16Z.
&&
.PREV DISCUSSION... /ISSUED 330 AM MST SAT DEC 21 2013/
SHORT TERM...SOME LOCALIZED FOG EARLY THIS MORNING EXTENDED FM
FORT COLLINS TOWARDS FORT MORGAN AS SHOWN BY CIRA IMAGERY BUT
SHOULD BURN OFF BY MID MORNING. OVERALL WILL CONTINUE TO SEE NW
FLOW ALOFT THRU TONIGHT AS A FEW WEAK DISTURBANCES TRACK ACROSS
NRN CO MAINLY TONIGHT. CROSS-SECTIONS SHOW MOISTURE WILL INCREASE
IN THE MTNS BY THIS AFTN AND CONTINUE OVERNIGHT WITH FAVORABLE
OROGRAPHICS AND LAPSE RATES AROUND 7 C/KM. THUS SNOW SHOULD
INCREASE THIS AFTN AND CONTINUE OVERNIGHT SO WILL ISSUE A WINTER
WEATHER WINTER ADVISORY WHICH WILL LINGER THRU MIDDAY SUN.
OTHERWISE OVER NERN CO IT SHOULD BE DRY THRU THE AFTN ALTHOUGH
COULD SEE A FEW LIGHT SNOW SHOWERS DEVELOP NR THE WY BORDER AND
OVER THE PALMER DIVIDE LATE. HIGHS THIS AFTN WILL BE IN THE 30S
OVER THE PLAINS.
BY THIS EVENING A SURGE OF COOLER AIR WILL MOVE INTO NERN CO AND
ENHANCE UPSLOPE FLOW ALONG THE FRONT RANGE. CROSS-SECTIONS SHOW
INCREASING MOISTURE BEHIND THIS FNT AND AS WK DISTURBANCE MOVES
ACROSS THIS EVENING SHOULD SEE A PERIOD OF LIGHT SNOW MAINLY IN AND
NEAR THE FOOTHILLS. AT THIS TIME ACCUMULATIONS SHOULD BE ONLY AN
INCH OR TWO. BY LATE TONIGHT THE UPSLOPE FLOW WILL GRADUALLY WEAKEN
AFTER MIDNIGHT SO SNOW SHOULD GRADUALLY END BY 09Z OR SO.
LONG TERM...BLOCKING MULTI-LEVEL HIGH PRESSURE RIDGE PRESENTLY OFF
THE WEST COAST OF NORTH AMERICA SHOWS LITTLE SIGNS OF MOVEMENT
DURING THE UPCOMING WEEK ACCORDING TO SHORT AND MEDIUM RANGE MODELS.
AS A CONSEQUENCE COLORADO WILL REMAIN UNDER MODERATELY STRONG
NORTHWEST FLOW DURING THE TIME PERIOD. MODELS SHOW A SERIES OF
SUBTLE UNDULATIONS IN THIS FLOW ROUNDING THE TOP OF THE RIDGE AND
PASSING OVER COLORADO...THE FIRST EXITING THE AREA SUNDAY
MORNING...ANOTHER PASSING BY SUNDAY EVENING...AND YET ANOTHER
PASSING THROUGH TUESDAY AFTERNOON AND/OR EVENING. RELYING ON THE
MODELS TO RESOLVE THESE WEAK PERTABATIONS AND THEIR SPEED OF
MOTION IN THIS FAST FLOW IS ASKING FOR DISAPPOINTMENT. THE SUNDAY
EVENING SYSTEM APPEARS TO HAVE THE BEST POTENTIAL FOR PRODUCING
SNOWFALL IN THE HIGH COUNTRY AND FOR PARTS OF NORTHEAST COLORADO.
GFS IS THE MOST OPTIMISTIC OF THE MODELS WITH SNOW CHANCES ON THE
PLAINS. HOWEVER THE NAM...GFS...ECMWF AND CANADIAN MODELS ALL
INDICATE THE PRESENCE OF THIS WAVE OVER NORTHEAST COLORADO SUNDAY
EVENING AND AT LEAST MIMINAL AMOUNTS OF QPF ACROSS THE NORTHEAST
CORNER OF THE STATE. SURROUNDING WFOS CONCUR AND SO HAVE UPPED
POPS TO 30-40 PCT IN ZONES ACROSS THE NORTHEAST CORNER SUNDAY
EVENING. SHOULD THEN SEE PRECIP/SNOW CHANCES FALL OFF AFTER 07Z
WITH THE JET LEVEL FORCING ALOFT EXITING THE AREA. ANY SNOW
ACCUMULATION SHOULD BE MINIMAL. MEANWHILE MOUNTAINS AND HIGH
VALLEYS HAVE A REASONABLE CHANCE OF MEASURING SNOWFALL WITH THIS
SYSTEM. FOR NOW...WILL GO WITH 40-60 PCT POPS IN THE MTN ZONES
AND 30-40 PCT POPS IN NORTH AND MIDDLE PARKS...ZONE 30 AND 32. SEE
LITTLE IF ANY CHANCE OF SNOW FOR SOUTH PARK ZONE 37 AS NORTHWEST
FLOW NOT CONDUCIVE FOR SNOWFALL HERE. COULD SEE A COUPLE INCHES
OF SNOW ON THE NORTHERN MTN RIDGES AND HIGH PASSES BY MONDAY
MORNING. NOT EXPECTING ANY SNOW IN THE I-25 URBAN CORRIDOR...
EXCEPT PERHAPS A DUSTING UP NEAR THE WYOMING BORDER.
THE LAST OF THESE WAVES IS PREDICTED BY THE EUROPEAN MODEL TO
PASS OVER NORTHEAST COLORADO TUESDAY EVENING. WHEREAS THE GFS
MODEL BARELY SHOWS A WAVE AND HARDLY ANY MOISTURE. HOWEVER...BOTH
MODELS SHOW A WEAK COLD FRONT SLIPPING SOUTH ACROSS NORTHEAST
COLORADO DURING THE AFTERNOON USHERING IN COLDER TEMPERATURES FOR
TUESDAY NIGHT AND WEDNESDAY/CHRISTMAS DAY. SO FOR NOW...WILL HANG
ONTO LOW POPS FOR TUESDAY EVENING IN THE MTNS...FOOTHILLS AND
ALONG THE PALMER DIVIDE JUST IN CASE THE ECMWF IS CORRECT.
WEDNESDAY AND BEYOND...A DRY AND COOL NORTHWEST FLOW REMAINS IN
PLACE THROUGH THE END OF THE WEEK WITH A UPPER RIDGE STILL OFF
THE WEST COAST. MODELS HINT AT THE PASSAGE OF YET ANOTHER SHORT
WAVE DISTURBANCE EITHER THURSDAY AFTERNOON OR NIGHT. BUT
CONFIDENCE IS LOW IN THE MODELS THAT FAR OUT. SO WILL KEEP THINGS
DRY AND TEMPERATURES NEAR TO SLIGHTLY ABOVE AVERAGE THURSDAY AND
FRIDAY.
AVIATION...WINDS WERE SE EARLY THIS MORNING WITH CIRA IMAGERY
SHOWING FOG CONFINED TO AREAS AROUND FORT COLLINS TO GREELEY. THE
HRRR KEEPS THIS FOG AND LOW CLOUDS OVER WELD COUNTY THROUGH THE
MORNING HOURS. HOWEVER THE RAP SHOWS A WEAK DENVER CYCLONE
DEVELOPING WITH WINDS BECOMING LIGHT NNW BY SUNRISE WITH THE
POTENTIAL FOR FOG AND LOW CLOUDS WHICH WOULD LINGER THRU THE LATE
MORNING HOURS OVER DIA. AT THIS POINT WILL HAVE TO MONITOR TRENDS
THE NEXT FEW HOURS AND SEE HOW THINGS DEVELOP.
FOR TONIGHT A SURGE OF COOLER AIR WILL AFFECT THE AREA BEHIND A FNT
WITH UPSLOPE FLOW DEVELOPING. AT THIS TIME MAY SEE A PERIOD OF
LIGHT SNOW ESPECIALLY IN THE 02Z-08Z TIMEFRAME WITH UP TO AN INCH OF
ACCUMULATION POSSIBLE. THE SNOW THREAT SHOULD END BY 09Z OR SO WITH
IMPROVING CONDITIONS.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 10 AM MST THIS MORNING FOR COZ038>040-
043>045.
WINTER WEATHER ADVISORY FROM NOON TODAY TO NOON MST SUNDAY FOR
COZ031-033-034.
&&
$$
SHORT TERM...RPK
LONG TERM....BAKER
AVIATION...RPK
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
330 AM MST SAT DEC 21 2013
.SHORT TERM...SOME LOCALIZED FOG EARLY THIS MORNING EXTENDED FM
FORT COLLINS TOWARDS FORT MORGAN AS SHOWN BY CIRA IMAGERY BUT
SHOULD BURN OFF BY MID MORNING. OVERALL WILL CONTINUE TO SEE NW
FLOW ALOFT THRU TONIGHT AS A FEW WEAK DISTURBANCES TRACK ACROSS
NRN CO MAINLY TONIGHT. CROSS-SECTIONS SHOW MOISTURE WILL INCREASE
IN THE MTNS BY THIS AFTN AND CONTINUE OVERNIGHT WITH FAVORABLE
OROGRAPHICS AND LAPSE RATES AROUND 7 C/KM. THUS SNOW SHOULD
INCREASE THIS AFTN AND CONTINUE OVERNIGHT SO WILL ISSUE A WINTER
WEATHER WINTER ADVISORY WHICH WILL LINGER THRU MIDDAY SUN.
OTHERWISE OVER NERN CO IT SHOULD BE DRY THRU THE AFTN ALTHOUGH
COULD SEE A FEW LIGHT SNOW SHOWERS DEVELOP NR THE WY BORDER AND
OVER THE PALMER DIVIDE LATE. HIGHS THIS AFTN WILL BE IN THE 30S
OVER THE PLAINS.
BY THIS EVENING A SURGE OF COOLER AIR WILL MOVE INTO NERN CO AND
ENHANCE UPSLOPE FLOW ALONG THE FRONT RANGE. CROSS-SECTIONS SHOW
INCREASING MOISTURE BEHIND THIS FNT AND AS WK DISTURBANCE MOVES
ACROSS THIS EVENING SHOULD SEE A PERIOD OF LIGHT SNOW MAINLY IN AND
NEAR THE FOOTHILLS. AT THIS TIME ACCUMULATIONS SHOULD BE ONLY AN
INCH OR TWO. BY LATE TONIGHT THE UPSLOPE FLOW WILL GRADUALLY WEAKEN
AFTER MIDNIGHT SO SNOW SHOULD GRADUALLY END BY 09Z OR SO.
.LONG TERM...BLOCKING MULTI-LEVEL HIGH PRESSURE RIDGE PRESENTLY OFF
THE WEST COAST OF NORTH AMERICA SHOWS LITTLE SIGNS OF MOVEMENT
DURING THE UPCOMING WEEK ACCORDING TO SHORT AND MEDIUM RANGE MODELS.
AS A CONSEQUENCE COLORADO WILL REMAIN UNDER MODERATELY STRONG
NORTHWEST FLOW DURING THE TIME PERIOD. MODELS SHOW A SERIES OF
SUBTLE UNDULATIONS IN THIS FLOW ROUNDING THE TOP OF THE RIDGE AND
PASSING OVER COLORADO...THE FIRST EXITING THE AREA SUNDAY
MORNING...ANOTHER PASSING BY SUNDAY EVENING...AND YET ANOTHER
PASSING THROUGH TUESDAY AFTERNOON AND/OR EVENING. RELYING ON THE
MODELS TO RESOLVE THESE WEAK PERTABATIONS AND THEIR SPEED OF
MOTION IN THIS FAST FLOW IS ASKING FOR DISAPPOINTMENT. THE SUNDAY
EVENING SYSTEM APPEARS TO HAVE THE BEST POTENTIAL FOR PRODUCING
SNOWFALL IN THE HIGH COUNTRY AND FOR PARTS OF NORTHEAST COLORADO.
GFS IS THE MOST OPTIMISTIC OF THE MODELS WITH SNOW CHANCES ON THE
PLAINS. HOWEVER THE NAM...GFS...ECMWF AND CANADIAN MODELS ALL
INDICATE THE PRESENCE OF THIS WAVE OVER NORTHEAST COLORADO SUNDAY
EVENING AND AT LEAST MIMINAL AMOUNTS OF QPF ACROSS THE NORTHEAST
CORNER OF THE STATE. SURROUNDING WFOS CONCUR AND SO HAVE UPPED
POPS TO 30-40 PCT IN ZONES ACROSS THE NORTHEAST CORNER SUNDAY
EVENING. SHOULD THEN SEE PRECIP/SNOW CHANCES FALL OFF AFTER 07Z
WITH THE JET LEVEL FORCING ALOFT EXITING THE AREA. ANY SNOW
ACCUMULATION SHOULD BE MINIMAL. MEANWHILE MOUNTAINS AND HIGH
VALLEYS HAVE A REASONABLE CHANCE OF MEASURING SNOWFALL WITH THIS
SYSTEM. FOR NOW...WILL GO WITH 40-60 PCT POPS IN THE MTN ZONES
AND 30-40 PCT POPS IN NORTH AND MIDDLE PARKS...ZONE 30 AND 32. SEE
LITTLE IF ANY CHANCE OF SNOW FOR SOUTH PARK ZONE 37 AS NORTHWEST
FLOW NOT CONDUCIVE FOR SNOWFALL HERE. COULD SEE A COUPLE INCHES
OF SNOW ON THE NORTHERN MTN RIDGES AND HIGH PASSES BY MONDAY
MORNING. NOT EXPECTING ANY SNOW IN THE I-25 URBAN CORRIDOR...
EXCEPT PERHAPS A DUSTING UP NEAR THE WYOMING BORDER.
THE LAST OF THESE WAVES IS PREDICTED BY THE EUROPEAN MODEL TO
PASS OVER NORTHEAST COLORADO TUESDAY EVENING. WHEREAS THE GFS
MODEL BARELY SHOWS A WAVE AND HARDLY ANY MOISTURE. HOWEVER...BOTH
MODELS SHOW A WEAK COLD FRONT SLIPPING SOUTH ACROSS NORTHEAST
COLORADO DURING THE AFTERNOON USHERING IN COLDER TEMPERATURES FOR
TUESDAY NIGHT AND WEDNESDAY/CHRISTMAS DAY. SO FOR NOW...WILL HANG
ONTO LOW POPS FOR TUESDAY EVENING IN THE MTNS...FOOTHILLS AND
ALONG THE PALMER DIVIDE JUST IN CASE THE ECMWF IS CORRECT.
WEDNESDAY AND BEYOND...A DRY AND COOL NORTHWEST FLOW REMAINS IN
PLACE THROUGH THE END OF THE WEEK WITH A UPPER RIDGE STILL OFF
THE WEST COAST. MODELS HINT AT THE PASSAGE OF YET ANOTHER SHORT
WAVE DISTURBANCE EITHER THURSDAY AFTERNOON OR NIGHT. BUT
CONFIDENCE IS LOW IN THE MODELS THAT FAR OUT. SO WILL KEEP THINGS
DRY AND TEMPERATURES NEAR TO SLIGHTLY ABOVE AVERAGE THURSDAY AND
FRIDAY.
&&
.AVIATION...WINDS WERE SE EARLY THIS MORNING WITH CIRA IMAGERY
SHOWING FOG CONFINED TO AREAS AROUND FORT COLLINS TO GREELEY. THE
HRRR KEEPS THIS FOG AND LOW CLOUDS OVER WELD COUNTY THROUGH THE
MORNING HOURS. HOWEVER THE RAP SHOWS A WEAK DENVER CYCLONE
DEVELOPING WITH WINDS BECOMING LIGHT NNW BY SUNRISE WITH THE
POTENTIAL FOR FOG AND LOW CLOUDS WHICH WOULD LINGER THRU THE LATE
MORNING HOURS OVER DIA. AT THIS POINT WILL HAVE TO MONITOR TRENDS
THE NEXT FEW HOURS AND SEE HOW THINGS DEVELOP.
FOR TONIGHT A SURGE OF COOLER AIR WILL AFFECT THE AREA BEHIND A FNT
WITH UPSLOPE FLOW DEVELOPING. AT THIS TIME MAY SEE A PERIOD OF
LIGHT SNOW ESPECIALLY IN THE 02Z-08Z TIMEFRAME WITH UP TO AN INCH OF
ACCUMULATION POSSIBLE. THE SNOW THREAT SHOULD END BY 09Z OR SO WITH
IMPROVING CONDITIONS.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM NOON TODAY TO NOON MST SUNDAY FOR
COZ031-033-034.
&&
$$
SHORT TERM...RPK
LONG TERM....BAKER
AVIATION...RPK
AREA FORECAST DISCUSSION
NWS ALBANY NY
626 AM EST SAT DEC 21 2013
.SYNOPSIS...
A SERIES OF LOW PRESSURE WAVES WILL PROPAGATE ALONG A NEARLY
STATIONARY FRONT FROM THE GREAT LAKES THROUGH NORTHERN NEW YORK
AND NORTHERN NEW ENGLAND THROUGH TONIGHT. A MUCH STRONGER STORM
WILL MOVE OUT OF THE OHIO VALLEY SUNDAY ALONG THIS FRONT. IN ITS
WAKE COLDER AIR WILL FILER BACK INTO THE REGION FOR THE FIRST HALF
OF THE WEEK. THE WEEKEND WILL FEATURE MILD TEMPERATURES FOR
DECEMBER...PERIODS OF RAIN BECOMING WIDESPREAD LATE SATURDAY INTO
SUNDAY WITH FREEZING RAIN ALONG THE NORTHERN TIER OF NEW YORK AND
NEW ENGLAND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 626 AM EST...A STALLED SURFACE FRONTAL BOUNDARY IS SITUATED
ACROSS FAR NORTHERN NEW YORK. AS A WEAK WAVE OF LOW PRESSURE MOVES
ALONG THIS BOUNDARY...THE FRONT WILL DROP SOUTH ACROSS THE
NORTHERN PORTION OF OUR CWA LATER TODAY. PERIODS OF RAIN WILL
ACCOMPANY THIS FRONTAL BOUNDARY THROUGHOUT THE DAY TODAY. THE
LATEST 3KM HRRR SUGGESTS ONE BATCH OF RAINFALL WILL MOVE ACROSS
THE REGION THIS MORNING...WITH A MORE STEADIER AND HEAVIER BATCH
OF RAIN TO OCCUR LATER THIS AFTERNOON AND INTO TONIGHT. TEMPS HAVE
WARMED UP ABOVE FREEZING ACROSS THE ENTIRE CWA...SO THERE IS NO
LONGER ANY THREAT FOR FZRA THIS MORNING.
A STRONG SOUTHERLY FLOW AT LOW LEVELS HAS ALLOWED TEMPS TO RANGE
FROM THE UPPER 30S TO UPPER 40S. DESPITE OVERCAST SKIES...TEMPS
WILL CONTINUE TO BE ABOVE NORMAL TODAY...AS A SOUTHERLY FLOW
CONTINUES TO THE SOUTH OF THE FRONTAL BOUNDARY. MAX TEMPS WILL
GENERALLY BE IN THE 40S...WITH SOME TEMPS NEAR 50 IN THE MID
HUDSON VALLEY.
TONIGHT...THE FRONTAL BOUNDARY WILL BECOME STALLED ACROSS
ADIRONDACKS...AS ANOTHER AND MUCH STRONGER WAVE OF LOW PRESSURE
BEGINS TO APPROACH FROM THE MISSISSIPPI AND TENNESSEE VALLEY
REGION. THERE WILL BE A STRONG THERMAL GRADIENT ASSOCIATED WITH
THIS BOUNDARY...WHICH WILL ALLOW FOR STRONG ISENTROPIC LIFT. 850 HPA
TEMPS WILL RANGE FROM AROUND +5 C OVER THE WESTERN ADIRONDACKS THIS
EVENING TO AS HIGH AS +14 DEGREES C BY LATE TONIGHT OVER THE
SOUTHEASTERN CORNER OF THE CWA.
WITH A STRONG AREA OF HIGH PRESSURE OVER WESTERN QUEBEC...THERE WILL
BE A VERY COLD AND DENSE AIR MASS SITUATED JUST NORTH OF OUR AREA.
THE STRONG AGEOSTROPHIC FLOW AT 925 HPA WILL ALLOW THIS COLD DENSE
AIR TO GET PULLED SOUTHWARD DOWN THE CHAMPLAIN VALLEY TONIGHT. AS A
RESULT...SFC TEMPS ACROSS THE LAKE GEORGE AREA WILL DROP BELOW
FREEZING ONCE AGAIN. WITH A WIDESPREAD RAIN EXPECTED
OVERNIGHT...THIS RAIN WILL FREEZE ON CONTACT...RESULTING IN FREEZING
RAIN ACROSS NORTHEASTERN WARREN AND NORTHERN WASHINGTON COUNTIES.
WE HAVE ISSUED A FREEZING RAIN ADVISORY TO ACCOUNT FOR THIS...WITH
A FEW TENTHS OF AN INCH POSSIBLE IN THESE LOCATIONS. THERE MAY BE
A FEW POCKETS OF FREEZING RAIN ACROSS THE FAR NORTHWESTERN
ADIRONDACKS...MAINLY NORTH OF OLD FORGE AND NORTHWEST OF INDIAN
LAKE...BUT ANY ICE ACCRETION IN THESE AREAS WILL BE VERY LIMITED
AND LOCALIZED. ELSEWHERE...A WIDESPREAD MODERATE TO LOCALLY HEAVY
RAIN WILL OCCUR FROM ABOUT THE CAPITAL REGION ON NORTH OVERNIGHT.
SOME RAIN WILL OCCUR ACROSS SOUTHERN AREAS AS WELL...ALTHOUGH THE
BEST PRECIP WILL BE LOCATED CLOSER TO THE TIGHT BAROCLINIC ZONE
ACROSS THE NORTHERN PORTION OF THE CWA. OUTSIDE OF THE LAKE GEORGE
AREA...TEMPS LOOK TO HOLD STEADY AND/OR SLOWLY RISE
OVERNIGHT...WITH MIN TEMPS OCCURRING EARLY IN THE PERIOD AND
RANGING FROM THE MID 30S TO MID 40S.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/...
BY SUNDAY MORNING STATIONARY FRONT REMAINS DRAPED FROM SW NYS TO
NR PWM. OVERRUNNING HAD BEEN THE PRIMARY DRIVER OF UVM AND PCPN
THROUGH SAT NT ALONG WITH AGEO CIRC ASSOC WITH RIGHT ENTRANCE RGN
OF INTENSE 300HPA JET. RAINS WILL HAVE OVERSPREAD THE ENTIRE FCA
MUCH OF THE NIGHT. BY SUN MRNG GFS HAS OVER 2 IN QPF IN ADIRONDACKS
TO LESS THAN 1 TENTH IN MID HUD VLY WITH A SOMEWHAT MORE GENEROUS
MAX IN THE NAM OF 2.6 IN.
SUNDAY A SHARP SHORT WV EJECTS INTO THE UPR MIDWEST...TRIGGERING A
MUCH DEEPER CYCLOGENESIS IN THE OHIO VLY THAN THE WAVES THAT HAD
BEEN RIPPLING ALONG THE STATIONARY FRONT TO THIS POINT. THE LOW
DEEPENS AS IT MOVES ACROSS FCA SUN. IN ADDITION THE PREVIOUSLY ACTING
ISENTROPIC LIFT AND JET DYNAMICS...CONVERGENCE WITH THE LOW AND
ALONG THE WMFNT WILL ENHANCE A BURST OF PCPN SUN WORKING WITH RICH
AIR MASS AND PW OF 1.25 IN OR BETTER.
SUNDAY THE MDLS DUMP ANOTHER TENTH OF AN INCH QPF IN MID HUD VLY
WITH ANOTHER TO 1.25 INCHES IN ADRNDKS. THE GEM HAS SIMILAR
NUMBERS WITH A MAX SHIFTED SLIGHTLY TO THE N OF US MDLS AND A
FRONTAL POSITION 50 OR SO MILES N.
IN SUMMARY QPF VALUES FM DETERMINISTIC MDLS ARE ANOTHER 0.5 TO 1.0
INCHES GREATER THAN PVS QPF. TOTALS ARE ON THE ORDER FROM 0.25 MID
HUD VLY TO 3 PLUS INCHES IN ADRNDKS. THE ECMWF AND GEM ARE ON THE
LIGHTER SIDE WITH A MAX QPF CLOSER TO 2 INCHES TOTAL. ADD TO THAT
THE SNOW PACK MELT. BY SUNDAY SNOW PACK WILL BE RIPE OR RIPENING
N. MOST WILL BE GONE IN THE SE. IN THE SE 1.0 LIQ OF SNOW PACK AND
A HALF AN INCH OF QPF SHOULDN`T PUSH RIVERS OUT OF THEIR BANKS.
HWVR FURTHER N...COLDER TEMPS EARLIER IN THE PERIOD HAVE SLOWED
SNOW MELT...WILL GIVE WAY TO 40S SUN WITH 2-3 INCHES OF QPF..AND
MAYBE AN INCH OF SNOW MELT.
AT THIS POINT WILL ISSUE A FLOOD WATCH FOR SAT NT THROUGH
SUN...WITH 2-3 IN QPF N TIER...AN INCH OF SNOW MELT. POTENTIAL FOR
WIDESPREAD MINOR FLOODING INCRG.
BY SUN NT SFC LOW EXISTS NY INTO N NEW ENG AND DRY SLOT MOVES INTO
RGN. RN SHOULD DIM TO SCT -SHRA BUT TEMPS WILL REMAIN ABV FREEZING
ACROSS MOST AREA...AND SNOW MELT AND RUNOFF WILL CONTINUE.
DURING SUNDAY AND SUN NT TEMPS ARE EITHER NON DIURNAL OR MAV/MET
MAX MIN VALUES ARE 24 HR VALUES FM SAT. WILL USE 3 HRLY TEMPS IN
GRIDS.
MONDAY THE SFC LOW AND ITS CDFNT MOVE EAST OF RGN. FCA WILL BE IN
DRY SLOT WITH VERY GRADUAL CAA. HWVR AT 500HPA MAJOR TROF IS BEING
CARVED OUT OVER GRTLKS AS SERIES OF SHORT WVS DIG S INTO IT. THIS
KEEPS A SW 500HPA FLOW OVR RGN...RESULTING IN A GRADUAL EXIT OF
FRONTAL SYSTEM AND GRADUAL COOL DOWN MONDAY. GFS/ECM PUSH SOME
PCPN INTO INTO FAR SE CORNER OF FCA MON. THIS IS MUCH LESS
PRONOUNCED THAN PVS RUNS...AND REALLY ONLY JUSTIFIES MAINTAINING
CHC POPS AT THIS TIME. DURING MON AND TUE CAA AND INCRG WIND
GRADIENT WILL BE THE RULE AS TEMPS RETURN TO NR OR BLO NORMAL
TUES WITH PASSAGE OF 500HPA TROF THROUGH RGN MONDAY NT AND TUES.
ITS FOLLOWED BY A MUCH STRONGER CDFNT AND BRISK N-NE WINDS IN ITS
WAKE.
CDFNT PASSAGE WILL TRIGGER SCT -SHSN MON NT...BUT H850 AND LLVL FLOW
NOT FAVORABLE FOR LK RESPONSE IN FCA TUE. TUES TEMPS WILL BE SVRL
DEG BLO NORMAL AS SFC HIGH BEGINS BUILDING SE FM OTTAWA VLY.
500HPA TROF MAY STILL BE SUF TO TRIGGER SCT INSTAB -SHSN TUES AND
TUE NT. SKIES WILL BE PC WITH MORE CLOUDS N AND FEWER S MON-TUE.
CHRISTMAS DAY WILL START ON THE FRIGID SIDE AS CLR SKIES...LARGE
SFC HIGH OVER RGN AND SOME OF THE LONGEST NIGHTS OF THE YEAR WILL
ALLOW IDEAL RADIATIONAL COOLING. MEX LOWS AT SLK ARE -19F TO +10
AT POU.
&&
.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
CHRISTMAS DAY 500HPA AND SFC RIDGE WILL CREST OVR RGN RESULTING IN
FAIR RATHER COLD DAY. AFTER FRIGID START TEMPS WILL REBOUND TO THE
TEENS AND LOW 20S. BY EVENING THE FLOW REGIME FOR THE REST OF THE
WEEK WILL BE SETTING UP WITH FAST W-NW FLOW ACROSS RGN. CLIPPER
TYPE TROF IN GFS (ECMWF CUTS IT OFF) RACES THROUGH UPR GRTLKS WED
NT INTO QB THU LEAVING AREA IN SLIGHTLY MILDER AIR MASS. SOME
MODELS SUG SOME -SHSN WITH IT...BUT MINOR AMOUNTS OR FLURRIES. WEEK
ENDS WITH GFS PUSHING A CDFNT INTO RGN AND BECOMING AN ANNA TYPE
FRONT WITH A PERIOD OF -SN SUGGESTED FRI FOLLOWED BY STRONG CAA
AND SOME LK EFFECT SAT. THE ECMWF CUTS OFF THE 500HPA LOW THU AND
BRINGS THIS FRONT QUICKLY THROUGH WITH THE CLIPPER THU. AS THIS
IS MAINLY A BLO NORMAL TEMP PERIOD WITH RATHER NON DESCRIPT WX
TIED TO FAST MOVING SYSTEMS WILL POPULATE REMAINDER OF EFP WITH
HPC MID SHIFT GRIDS.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
FLYING CONDITIONS ARE CURRENTLY HIGH END MVFR TO VFR ACROSS THE
REGION WITH INCREASING AMOUNTS OF CLOUDINESS. REGIONAL MOSAIC
RADAR SHOWS RAIN SHOWERS APPROACHING FROM CENTRAL NY FOR LATER
THIS MORNING. THIS WILL ALLOW FOR WIDESPREAD MVFR CONDITIONS...AND
POSSIBLY PERIODS OF IFR FOR THE MID TO LATE MORNING HOURS INTO THE
EARLY AFTN DUE TO RAIN...MIST AND LOW STRATUS CLOUDS. IT MAY TAKE
UNTIL LATE IN THE DAY FOR THE RAIN TO REACH KPOU...WHEN A MORE
STEADIER AND HEAVIER RAINFALL ARRIVES. THIS RAIN WILL CONTINUE
THROUGH TONIGHT WITH WIDESPREAD IFR CONDITIONS.
LLWS WILL BE IN PLACE THROUGH EARLY THIS AFTN WITH 2 KFT WINDS AROUND
35-40 KTS OUT OF THE WEST-SOUTHWEST. MEANWHILE...SFC WINDS WILL BE
MAINLY LIGHT...BECOMING SOUTHERLY AT 10 KTS OR LESS. LLWS SHOULD
END BY THIS AFTN AS THE BEST LOW LEVEL JET SHIFTS AWAY FROM THE
AREA. SFC WINDS WILL REMAIN LIGHT RIGHT INTO TONIGHT.
OUTLOOK...
SUNDAY: HIGH OPERATIONAL IMPACT. RA.
SUNDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA.
MONDAY: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA.
MONDAY NIGHT-TUESDAY NIGHT: LOW OPERATIONAL IMPACT. BREEZY.
SLIGHT CHANCE OF SHSN.
CHRISTMAS DAY-WED NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
&&
.HYDROLOGY...
MILD TO UNSEASONABLY WARM TEMPERATURES WILL OCCUR THROUGH THE
WEEKEND WITH INCREASING SNOW MELT. MEANWHILE A SERIES OF LOW
PRESSURE SYSTEMS WILL BE PROPAGATING ALONG A NEARLY STATIONARY
FRONT FROM THE NIAGARA FRONTIER TO VERMONT WITH 2-3 INCHES OF RAIN
EXPECTED IN THE ADIRONDACKS...BUT LESSER AMOUNTS SOUTH.
TEMPERATURES SUNDAY ARE EXPECTED TO WARM INTO THE 50S IN MOST
AREAS...MID 40S FAR NORTH AND 60S SOUTH OF ALBANY.
IN THE NORTH RAINFALL AMOUNTS WILL BE GREATEST...BUT SNOW MELT
SLOWER...WHILE IN THE SOUTH RAINFALL WILL BE AROUND A HALF
INCH...BUT ALMOST ALL SNOW WILL MELT. IN THE SOUTH THIS WILL BE
SUFFICIENT FOR SIGNIFICANT WITHIN BANK RISES...BUT FLOODING IS NOT
EXPECTED AT THIS TIME.
THE GREATEST POTENTIAL FOR FLOODING WILL EXIST FROM THE MOHAWK
VALLEY INTO THE ADIRONDACKS WHERE 2 TO 3 INCHES OF RAIN AND UP TO
AN INCH OF LIQUID EQUIVALENT FROM SNOW MELT IS EXPECTED. FLOOD
WATCHES HAVE BEEN ISSUED FOR TONIGHT THROUGH SUNDAY NIGHT.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...FLOOD WATCH FROM THIS EVENING THROUGH MONDAY MORNING FOR
NYZ032-033-038>040-042-043-082.
FREEZING RAIN ADVISORY FROM 7 PM THIS EVENING TO 11 AM EST
SUNDAY FOR NYZ042-043.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...SNYDER
NEAR TERM...FRUGIS
SHORT TERM...SNYDER
LONG TERM...SNYDER
AVIATION...FRUGIS
HYDROLOGY...SNYDER
AREA FORECAST DISCUSSION
NWS ALBANY NY
222 AM EST SAT DEC 21 2013
.SYNOPSIS...
A SERIES OF LOW PRESSURE WAVES WILL PROPAGATE ALONG A NEARLY
STATIONARY FRONT FROM THE GREAT LAKES THROUGH NORTHERN NEW YORK
AND NORTHERN NEW ENGLAND THROUGH TONIGHT. A MUCH STRONGER STORM
WILL MOVE OUT OF THE OHIO VALLEY SUNDAY ALONG THIS FRONT. IN ITS
WAKE COLDER AIR WILL FILER BACK INTO THE REGION FOR THE FIRST HALF
OF THE WEEK. THE WEEKEND WILL FEATURE MILD TEMPERATURES FOR
DECEMBER...PERIODS OF RAIN BECOMING WIDESPREAD LATE SATURDAY INTO
SUNDAY WITH FREEZING RAIN ALONG THE NORTHERN TIER OF NEW YORK AND
NEW ENGLAND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1218 AM EST...BATCH OF RAIN IS NOW EXITING SOUTHERN
VERMONT...WITH JUST VERY LIGHT SPRINKLES AND RAIN SHOWERS
REMAINING OVER EASTERN NY. THIS LOOKS TO BE A BREAK IN THE
PRECIP...AS DEPICTED BY THE HRRR AND LOCAL HIRES WRF. ADDITIONAL
RAINFALL...NOTED ON THE REGIONAL MOSAIC RADAR ACROSS WESTERN NEW
YORK...WILL BE APPROACHING FOR THE LATE OVERNIGHT HOURS...SO WILL
CONTINUE WITH RATHER HIGH POPS ACROSS NORTHERN PARTS OF THE AREA.
TEMPERATURES ARE STILL ABOVE FREEZING ACROSS MUCH OF THE AREA
EXCEPT FOR A LIMITED AREA OF FAR NORTHERN WARREN AND WASHINGTON
COUNTIES WHERE NORTHERLY WINDS HAVE ALLOWED COLD AIR TO DRAIN
SOUTHWARD THROUGH THE CHAMPLAIN VALLEY TO THE LAKE GEORGE REGION.
TEMPS IN THE NORTHERN PART OF THE LAKE GEORGE AREA ARE IN THE MID
TO UPPER 20S...WITH LOW TO MID 30S ACROSS SOUTHERN PARTS OF THE
LAKE. A FREEZING RAIN ADVISORY REMAINS IN EFFECT THERE THROUGH 6
AM. WILL CONTINUE TO MENTION UP TO ONE TENTH OF AN INCH OF ICE IN
THIS SMALL AREA. TEMPS SHOULD GRADUALLY WARM UP THROUGH THE NIGHT
IN THIS AREA. FOR SOME AREAS WHERE MIXING HAS BEEN ABLE TO
OCCUR...TEMPS HAVE RISEN INTO THE LOWER TO MID 40S. TEMPERATURES
ARE GENERALLY EXPECTED TO REMAIN STEADY THROUGH THE NIGHT FOR THE
REMAINDER OF THE AREA.
STRONGER UPPER LEVEL ENERGY...FORCING AND MOISTURE ADVECTION
APPROACHES SATURDAY AFTERNOON THROUGH SUNDAY AFTERNOON. HEAVIER
RAINFALL SHOULD SPREAD ACROSS THE REGION SATURDAY AFTERNOON AND
NIGHT...WITH THE HEAVIEST RAIN OCCURRING SATURDAY NIGHT INTO EARLY
SUNDAY. THERE ARE CONSIDERABLE DISAGREEMENTS IN SOURCES OF GUIDANCE
AND ENSEMBLES AS TO HOW MUCH COLDER AIR SINKS SOUTH SATURDAY NIGHT
IN RESPONSE TO ENHANCED UPPER CONFLUENCE IN CANADA AS UPPER ENERGY
TRACKS WELL NORTH OF THE U.S. CANADIAN BORDER. ENOUGH COLD AIR COULD
SINK SOUTHWARD AGAIN SATURDAY NIGHT TO PRODUCE SOME FREEZING RAIN.
MODELS INDICATE THAT ANY PERIOD OF NEAR OR BELOW FREEZING TEMPS
ALONG THE NORTHERN BORDER OF THE FORECAST AREA WOULD BE BRIEF AND
ONLY PRODUCE LIGHT ICING AMOUNTS (UNDER A QUARTER OF AN INCH). NO
WINTER STORM WATCH WILL BE ISSUED AND IF APPEARS MORE CERTAIN THAT
SOME FREEZING RAIN WILL FALL LATE SATURDAY NIGHT...THEN ADVISORIES
CAN BE ISSUED ON SATURDAY.
A VERY STRONG BOUNDARY LAYER JET SEGMENT AND ISENTROPIC LIFT...ALONG
WITH ANOMALOUSLY HIGH PWAT...SHOULD SUPPORT A HEAVY RAIN EVENT...AND
COMBINED WITH SNOW MELT...COULD RESULT IN SOME FLOODING POTENTIAL.
THIS WILL BE ADDRESSED IN THE HWO AS RAINFALL FORECASTS FROM SOURCES
OF GUIDANCE AND ENSEMBLES STILL INDICATE THAT A BROAD RANGE AND AXIS
OF HEAVIEST RAIN COULD FALL NORTH OF WHERE MAXIMUM SNOW MELT OCCURS.
A WEST TO SOUTHWEST BOUNDARY LAYER FLOW USUALLY RESULTS IN THE
HEAVIEST PRECIPITATION IN THE ADIRONDACKS...WHICH AGAIN MAY SEE THE
LEAST WARM TEMPERATURES AND LEAST SNOW MELT. SO...STILL HOLDING OFF
ON ANY FLOOD WATCHES.
HIGHS SATURDAY IN THE 40S TO LOWER 50S...LOWS SATURDAY IN THE 40S
OVER THE SOUTHERN TWO-THIRDS OF THE FORECAST AREA...AND 30S NORTH.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/...
BY SUNDAY MORNING STATIONARY FRONT REMAINS DRAPED FROM SW NYS TO
NR PWM. OVERRUNNING HAD BEEN THE PRIMARY DRIVER OF UVM AND PCPN
THROUGH SAT NT ALONG WITH AGEO CIRC ASSOC WITH RIGHT ENTRANCE RGN
OF INTENSE 300HPA JET. RAINS WILL HAVE OVERSPREAD THE ENTIRE FCA
MUCH OF THE NIGHT. BY SUN MRNG GFS HAS OVER 2 IN QPF IN ADIRONDACKS
TO LESS THAN 1 TENTH IN MID HUD VLY WITH A SOMEWHAT MORE GENEROUS
MAX IN THE NAM OF 2.6 IN.
SUNDAY A SHARP SHORT WV EJECTS INTO THE UPR MIDWEST...TRIGGERING A
MUCH DEEPER CYCLOGENISUS IN THE OHIO VLY THAN THE WAVES THAT HAD
BEEN RIPPLING ALONG THE STATIONARY FRONT TO THIS POINT. THE LOW
DEEPENS AS IT MOVES ACROSS FCA SUN. IN ADDITION THE PREVIOUSLY ACTING
ISENTROPIC LIFT AND JET DYNAMICS...CONVERGENCE WITH THE LOW AND
ALONG THE WMFNT WILL ENHANCE A BURST OF PCPN SUN WORKING WITH RICH
AIR MASS AND PW OF 1.25 IN OR BETTER.
SUNDAY THE MDLS DUMP ANOTHER TENTH OF AN INCH QPF IN MID HUD VLY
WITH ANOTHER TO 1.25 INCHES IN ADRNDKS. THE GEM HAS SIMILAR
NUMBERS WITH A MAX SHIFTED SLIGHTLY TO THE N OF US MDLS AND A
FRONTAL POSITION 50 OR SO MILES N.
IN SUMMARY QPF VALUES FM DETERMINISTIC MDLS ARE ANOTHER 0.5 TO 1.0
INCHES GREATER THAN PVS QPF. TOTALS ARE ON THE ORDER FROM 0.25 MID
HUD VLY TO 3 PLUS INCHES IN ADRNDKS. THE ECMWF AND GEM ARE ON THE
LIGHTER SIDE WITH A MAX QPF CLOSER TO 2 INCHES TOTAL. ADD TO THAT
THE SNOW PACK MELT. BY SUNDAY SNOW PACK WILL BE RIPE OR RIPENING
N. MOST WILL BE GONE IN THE SE. IN THE SE 1.0 LIQ OF SNOW PACK AND
A HALF AN INCH OF QPF SHOULDN`T PUSH RIVERS OUT OF THEIR BANKS.
HWVR FURTHER N...COLDER TEMPS EARLIER IN THE PERIOD HAVE SLOWED
SNOW MELT...WILL GIVE WAY TO 40S SUN WITH 2-3 INCHES OF QPF..AND
MAYBE AN INCH OF SNOW MELT.
AT THIS POINT AN LEANING TWRD A FLOOD WATCH FOR SAT NT THROUGH SUN...WITH
2-3 IN QPF N TIER...AN INCH OF SNOW MELT. POTENTIAL FOR WIDESPREAD
MINOR FLOODING INCRG.
BY SUN NT SFC LOW EXISTS NY INTO N NEW ENG AND DRY SLOT MOVES INTO
RGN. RN SHOULD DIM TO SCT -SHRA BUT TEMPS WILL REMAIN ABV FREEZING
ACROSS MOST AREA...AND SNOW MELT AND RUNOFF WILL CONTINUE.
DURING SUNDAY AND SUN NT TEMPS ARE EITHER NON DIURNAL OR MAV/MET
MAX MIN VALUES ARE 24 HRS VALUES FM SAT AND WILL USE 3 HRLY TEMPS
MONDAY THE SFC LOW AND ITS CDFNT MOVE EAST OF RGN. AND DURING MON
AND TUE CAA AND INCRG WIND GRADIENT WILL BE THE RULE AS TEMPS
RETURN TO NR OR BLO NORMAL TUES.
MON FCA WILL BE IN DRY SLOT WITH VERY GRADUAL CAA. HWVR AT 500HPA
MAJOR TROF IS BEING CARVED OUT OVER GRTLKS AS SERIES OF SHORT WVS
DIG S INTO IT. MONDAY NGT AND TUES THE 500HPA TROF MOVES ACROSS
FCA WITH MUCH STRONGER CDFNT AND BRISK N-NE WINDS IN ITS WAKE.
CDFNT PASSAGE WILL TRIGGER SCT -SHSN MON NT...BUT H850 AND LLVL FLOW
NOT FAVORABLE FOR LK RESPONSE IN FCA TUE. TUES AND CHRISTMAS TEMPS
WILL BE SVRL DEG BLO NORMAL AS SFC HIGH BEGINS BUILDING SE FM
OTTAWA VLY. 500HPA TROF MAY STILL BE SUF TO TRIGGER SCT INSTAB
-SHSN TUES AND TUE NT. SKIES WILL BE PC WITH MORE CLOUDS N AND
FEWER S MON-TUE. CHRISTMAS DAY SHOULD BE BRIGHTER AND SUNNY AS SFC
HIGH CRESTS OVER THE REGION, HWVR IT WILL START ON THE FRIGID SIDE
AS CLR SKIES ON SOME OF THE LONGEST NIGHTS OF THE YEAR WILL ALLOW
IDEAL RADIATIONAL COOLING. MEX LOWS AT SLK ARE -19F TO +10 AT
POU.
&&
.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
DRY CONDITIONS SHOULD PERSIST WEDNESDAY NIGHT...ALTHOUGH A BIT OF
A SOUTHERLY GRADIENT DEVELOPS AROUND THE DEPARTING HIGH WHICH
COULD ALLOW FOR MILDER TEMPERATURES DEPENDING ON THE AMOUNT OF
MIXING AT NIGHT.
THE FORECAST BECOMES A BIT MORE MURKY FROM THURSDAY INTO FRIDAY...AS
ENERGY ASSOCIATED WITH AN UPPER LEVEL TROUGH MOVES EASTWARD ACROSS
THE GREAT LAKES...WHILE THERE IS THE POTENTIAL FOR A SOUTHERN STREAM
DISTURBANCE TO PHASE WITH THE PRIMARY TROUGH. THE ECMWF IS MOST
AGGRESSIVE WITH THIS SCENARIO...WHICH COULD LEAD TO A MORE
WIDESPREAD MODERATE PRECIP EVENT. THE GFS IS MUCH MORE PROGRESSIVE
THOUGH...SO WILL CONSERVATIVELY MENTION LOW CHANCE POPS AT THIS TIME.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
IFR CONDITIONS DUE TO RAIN AND FOG CONTINUE TO KGFL AND THIS LOOKS
TO CONTINUE FOR THE REMAINDER OF THE OVERNIGHT HOURS.
MEANWHILE...VFR CONDITIONS ARE IN PLACE FOR THE OTHER REMAINING
TAF SITES...WITH CIGS GENERALLY 4-8 KFT. CIGS WILL GRADUALLY
LOWER TO MVFR FOR KALB/KPSF TOWARDS DAYBREAK...ESP AS THE NEXT
BATCH OF RAIN CURRENTLY OVER WESTERN NY APPROACHES THE REGION.
KPSF/KPOU SHOULD BE ABLE TO AVOID MOST OF THIS NEXT BATCH OF
RAIN...WITH MAINLY KGFL/KALB TO BE IMPACTED.
DURING THE DAY SATURDAY...CONDITIONS WILL LOWER TO IFR FOR ALL
SITES WITH RAIN...MIST...AND LOW STRATUS CLOUDS. IT MAY TAKE
UNTIL LATE IN THE DAY FOR THE RAIN TO REACH KPOU. THE STEADIEST
AND HEAVIEST RAIN LOOKS TO OCCUR SAT EVENING INTO SAT NIGHT.
LLWS WILL BE IN PLACE THROUGH MUCH OF THE TAF PERIOD WITH 2 KFT
WINDS AROUND 35-40 KTS OUT OF THE WEST-SOUTHWEST. MEANWHILE...SFC
WINDS WILL BE MAINLY LIGHT OVERNIGHT INTO THE DAY SATURDAY...BECOMING
SOUTHERLY AT 10 KTS OR LESS. LLWS SHOULD END BY SAT AFTN AS THE
BEST LOW LEVEL JET SHIFTS AWAY FROM THE AREA.
OUTLOOK...
SATURDAY NIGHT: HIGH OPERATIONAL IMPACT. DEFINITE RA.
SUNDAY: HIGH OPERATIONAL IMPACT. LIKELY RA.
SUNDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA.
MONDAY: MODERATE OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA...SHSN.
MONDAY NIGHT: MODERATE OPERATIONAL IMPACT. SCATTERED SHSN.
TUESDAY: LOW OPERATIONAL IMPACT.BREEZY ISOLATED SHSN.
TUESDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
WEDNESDAY: NO OPERATIONAL IMPACT. NO SIG WX.
&&
.HYDROLOGY...
MILD TO UNSEASONABLY WARM TEMPERATURES WILL OCCUR THROUGH THE
WEEKEND...WHICH MEANS SNOW MELT IS LIKELY THIS WEEKEND. ALSO...A
STORM SYSTEM MOVING ALONG A FRONTAL BOUNDARY MAY BRING SIGNIFICANT
PCPN TO THE FORECAST AREA SAT NIGHT INTO SUNDAY.
TEMPERATURES SUNDAY ARE EXPECTED TO WARM INTO THE 50S OR POSSIBLY
EVEN 60S ACROSS THE EASTERN CATSKILLS...MID HUDSON VALLEY...CENTRAL
AND SOUTHERN TACONICS INTO THE BERKSHIRES AND ACROSS LITCHFIELD
COUNTY WITH 50S ACROSS THE CAPITAL REGION...40S FURTHER NORTH.
BETWEEN THE RAIN AND RUNOFF FROM SNOWMELT DUE TO THE MILD/WARM
TEMPERATURES...SOME FLOODING COULD BE A PROBLEM INCLUDING ICE JAMS
ISSUES. AT THIS POINT...WE BELIEVE MOST IF NOT ALL OF THE SNOW COULD
BE MELTED FROM ABOUT THE MOHAWK RIVER SOUTH. FURTHER NORTH...
TEMPERATURES MIGHT NOT BE WARM ENOUGH TO MELT ALL OF THE SNOW.
THE POTENTIAL IS THERE FOR 1-2.5 INCHES OF RAINFALL FROM ALBANY
NORTHWARD...POSSIBLY SOME AREAS REACHING 3 INCHES. LESSER AMOUNTS OF
RAIN LOOK TO FALL SOUTH OF THE CAPITAL REGION...AN INCH OR LESS.
WILL KEEP MENTION OF IN OUR HAZARDOUS WEATHER OUTLOOK.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...FREEZING RAIN ADVISORY UNTIL 6 AM EST EARLY THIS MORNING FOR
NYZ042-043.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...GJM/SNYDER
NEAR TERM...FRUGIS/GJM/JPV
SHORT TERM...SNYDER
LONG TERM...JPV
AVIATION...FRUGIS
HYDROLOGY...GJM/NAS
AREA FORECAST DISCUSSION
NWS ALBANY NY
1218 AM EST SAT DEC 21 2013
.SYNOPSIS...
A NEARLY STATIONARY FRONT FROM THE GREAT LAKES THROUGH NORTHERN
NEW YORK AND NORTHERN NEW ENGLAND WILL PRODUCE SCATTERED LIGHT
PRECIPITATION TONIGHT. THE FRONT WILL SINK SOUTH AS A COLD FRONT
INTO PARTS OF CENTRAL NEW YORK AND SOUTHERN VERMONT BY SATURDAY
NIGHT...SUPPORTING CHANCES FOR FREEZING RAIN IN THE NORTH COUNTRY.
STRONG LOW PRESSURE WILL TRACK NORTHEAST OUT OF THE TENNESSEE AND
OHIO VALLEY SUNDAY AS THE FRONT SURGES NORTH INTO CANADA.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 1218 AM EST...BATCH OF RAIN IS NOW EXITING SOUTHERN
VERMONT...WITH JUST VERY LIGHT SPRINKLES AND RAIN SHOWERS
REMAINING OVER EASTERN NY. THIS LOOKS TO BE A BREAK IN THE
PRECIP...AS DEPICTED BY THE HRRR AND LOCAL HIRES WRF. ADDITIONAL
RAINFALL...NOTED ON THE REGIONAL MOSAIC RADAR ACROSS WESTERN NEW
YORK...WILL BE APPROACHING FOR THE LATE OVERNIGHT HOURS...SO WILL
CONTINUE WITH RATHER HIGH POPS ACROSS NORTHERN PARTS OF THE AREA.
TEMPERATURES ARE STILL ABOVE FREEZING ACROSS MUCH OF THE AREA
EXCEPT FOR A LIMITED AREA OF FAR NORTHERN WARREN AND WASHINGTON
COUNTIES WHERE NORTHERLY WINDS HAVE ALLOWED COLD AIR TO DRAIN
SOUTHWARD THROUGH THE CHAMPLAIN VALLEY TO THE LAKE GEORGE REGION.
TEMPS IN THE NORTHERN PART OF THE LAKE GEORGE AREA ARE IN THE MID
TO UPPER 20S...WITH LOW TO MID 30S ACROSS SOUTHERN PARTS OF THE
LAKE. A FREEZING RAIN ADVISORY REMAINS IN EFFECT THERE THROUGH 6
AM. WILL CONTINUE TO MENTION UP TO ONE TENTH OF AN INCH OF ICE IN
THIS SMALL AREA. TEMPS SHOULD GRADUALLY WARM UP THROUGH THE NIGHT
IN THIS AREA. FOR SOME AREAS WHERE MIXING HAS BEEN ABLE TO
OCCUR...TEMPS HAVE RISEN INTO THE LOWER TO MID 40S. TEMPERATURES
ARE GENERALLY EXPECTED TO REMAIN STEADY THROUGH THE NIGHT FOR THE
REMAINDER OF THE AREA.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH SUNDAY NIGHT/...
STRONGER UPPER LEVEL ENERGY...FORCING AND MOISTURE ADVECTION
APPROACHES SATURDAY AFTERNOON THROUGH SUNDAY AFTERNOON. HEAVIER
RAINFALL SHOULD SPREAD ACROSS THE REGION SATURDAY AFTERNOON AND
NIGHT...WITH THE HEAVIEST RAIN OCCURRING SATURDAY NIGHT INTO EARLY
SUNDAY. THERE ARE CONSIDERABLE DISAGREEMENTS IN SOURCES OF GUIDANCE
AND ENSEMBLES AS TO HOW MUCH COLDER AIR SINKS SOUTH SATURDAY NIGHT
IN RESPONSE TO ENHANCED UPPER CONFLUENCE IN CANADA AS UPPER ENERGY
TRACKS WELL NORTH OF THE U.S. CANADIAN BORDER. ENOUGH COLD AIR COULD
SINK SOUTHWARD AGAIN SATURDAY NIGHT TO PRODUCE SOME FREEZING RAIN.
MODELS INDICATE THAT ANY PERIOD OF NEAR OR BELOW FREEZING TEMPS
ALONG THE NORTHERN BORDER OF THE FORECAST AREA WOULD BE BRIEF AND
ONLY PRODUCE LIGHT ICING AMOUNTS (UNDER A QUARTER OF AN INCH). NO
WINTER STORM WATCH WILL BE ISSUED AND IF APPEARS MORE CERTAIN THAT
SOME FREEZING RAIN WILL FALL LATE SATURDAY NIGHT...THEN ADVISORIES
CAN BE ISSUED ON SATURDAY.
A VERY STRONG BOUNDARY LAYER JET SEGMENT AND ISENTROPIC LIFT...ALONG
WITH ANOMALOUSLY HIGH PWAT...SHOULD SUPPORT A HEAVY RAIN EVENT...AND
COMBINED WITH SNOW MELT...COULD RESULT IN SOME FLOODING POTENTIAL.
THIS WILL BE ADDRESSED IN THE HWO AS RAINFALL FORECASTS FROM SOURCES
OF GUIDANCE AND ENSEMBLES STILL INDICATE THAT A BROAD RANGE AND AXIS
OF HEAVIEST RAIN COULD FALL NORTH OF WHERE MAXIMUM SNOW MELT OCCURS.
A WEST TO SOUTHWEST BOUNDARY LAYER FLOW USUALLY RESULTS IN THE
HEAVIEST PRECIPITATION IN THE ADIRONDACKS...WHICH AGAIN MAY SEE THE
LEAST WARM TEMPERATURES AND LEAST SNOW MELT. SO...STILL HOLDING OFF
ON ANY FLOOD WATCHES.
HIGHS SATURDAY IN THE 40S TO LOWER 50S...LOWS SATURDAY IN THE 40S
OVER THE SOUTHERN TWO-THIRDS OF THE FORECAST AREA...AND 30S NORTH.
HIGHS SUNDAY 45 TO 55 NORTH...AND 55 TO 65 SOUTH. LOWS SUNDAY NIGHT
IN THE 40S SOUTH...30S NORTH.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
THE PERIOD STARTS OUT ON MONDAY WITH COLDER AIR GRADUALLY FILTERING
INTO THE REGION WITH A WSW FLOW BECOMING WNW. A FRONTAL BOUNDARY TO
OUR SOUTH OVER THE MID ATLANTIC REGION IS FORECAST TO STALL...WITH A
WAVE OF LOW PRESSURE MOVING NORTHEASTWARD ALONG THE FRONT. SOME
LIGHT RAIN ASSOCIATED WITH THIS WAVE COULD AFFECT AREAS MAINLY SOUTH
AND EAST OF ALBANY. THE GFS/ECMWF HAS SOME LIGHT QPF JUST SCRAPING
OUR SOUTHEAST ZONES...WHILE THE NAM IS MOST AGGRESSIVE WITH BRINGING
THE WAVE AND ASSOCIATED QPF NORTHWARD. WILL MENTION CHANCE POPS FOR
NOW...WITH ANOTHER AREA OF CHANCE POPS ACROSS NORTHWEST AREAS DUE TO
SOME LAKE ENHANCED/UPSLOPE SNOW SHOWERS DEVELOPING.
TEMPERATURES SHOULD DROP SIGNIFICANTLY MONDAY NIGHT INTO CHRISTMAS
EVE MORNING...AS STRONG COLD ADVECTION COMMENCES. THE FLOW
TRAJECTORY IS FORECAST TO SHIFT TO THE NORTHWEST...SO SOME
MULTI-BAND LAKE EFFECT SNOW SHOWERS COULD IMPACT THE MOHAWK AND
SCHOHARIE VALLEY...AS WELL AS THE NORTHERN CATSKILLS CHRISTMAS EVE
DAY. CHRISTMAS EVE NIGHT THROUGH CHRISTMAS DAY LOOKS TO BE DRY BUT
COLD REGION-WIDE...AS HIGH PRESSURE BUILDS IN THEN SHIFTS EASTWARD
INTO NEW ENGLAND BY LATE CHRISTMAS DAY. DRY CONDITIONS SHOULD
PERSIST WEDNESDAY NIGHT...ALTHOUGH A BIT OF A SOUTHERLY GRADIENT
DEVELOPS AROUND THE DEPARTING HIGH WHICH COULD ALLOW FOR MILDER
TEMPERATURES DEPENDING ON THE AMOUNT OF MIXING AT NIGHT.
THE FORECAST BECOMES A BIT MORE MURKY FROM THURSDAY INTO FRIDAY...AS
ENERGY ASSOCIATED WITH AN UPPER LEVEL TROUGH MOVES EASTWARD ACROSS
THE GREAT LAKES...WHILE THERE IS THE POTENTIAL FOR A SOUTHERN STREAM
DISTURBANCE TO PHASE WITH THE PRIMARY TROUGH. THE ECMWF IS MOST
AGGRESSIVE WITH THIS SCENARIO...WHICH COULD LEAD TO A MORE
WIDESPREAD MODERATE PRECIP EVENT. THE GFS IS MUCH MORE PROGRESSIVE
THOUGH...SO WILL CONSERVATIVELY MENTION LOW CHANCE POPS AT THIS TIME.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
IFR CONDITIONS DUE TO RAIN AND FOG CONTINUE TO KGFL AND THIS LOOKS
TO CONTINUE FOR THE REMAINDER OF THE OVERNIGHT HOURS.
MEANWHILE...VFR CONDITIONS ARE IN PLACE FOR THE OTHER REMAINING
TAF SITES...WITH CIGS GENERALLY 4-8 KFT. CIGS WILL GRADUALLY
LOWER TO MVFR FOR KALB/KPSF TOWARDS DAYBREAK...ESP AS THE NEXT
BATCH OF RAIN CURRENTLY OVER WESTERN NY APPROACHES THE REGION.
KPSF/KPOU SHOULD BE ABLE TO AVOID MOST OF THIS NEXT BATCH OF
RAIN...WITH MAINLY KGFL/KALB TO BE IMPACTED.
DURING THE DAY SATURDAY...CONDITIONS WILL LOWER TO IFR FOR ALL
SITES WITH RAIN...MIST...AND LOW STRATUS CLOUDS. IT MAY TAKE
UNTIL LATE IN THE DAY FOR THE RAIN TO REACH KPOU. THE STEADIEST
AND HEAVIEST RAIN LOOKS TO OCCUR SAT EVENING INTO SAT NIGHT.
LLWS WILL BE IN PLACE THROUGH MUCH OF THE TAF PERIOD WITH 2 KFT
WINDS AROUND 35-40 KTS OUT OF THE WEST-SOUTHWEST. MEANWHILE...SFC
WINDS WILL BE MAINLY LIGHT OVERNIGHT INTO THE DAY SATURDAY...BECOMING
SOUTHERLY AT 10 KTS OR LESS. LLWS SHOULD END BY SAT AFTN AS THE
BEST LOW LEVEL JET SHIFTS AWAY FROM THE AREA.
OUTLOOK...
SATURDAY NIGHT: HIGH OPERATIONAL IMPACT. DEFINITE RA.
SUNDAY: HIGH OPERATIONAL IMPACT. LIKELY RA.
SUNDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA.
MONDAY: MODERATE OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA...SHSN.
MONDAY NIGHT: MODERATE OPERATIONAL IMPACT. SCATTERED SHSN.
TUESDAY: LOW OPERATIONAL IMPACT.BREEZY ISOLATED SHSN.
TUESDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
WEDNESDAY: NO OPERATIONAL IMPACT. NO SIG WX.
&&
.HYDROLOGY...
MILD TO UNSEASONABLY WARM TEMPERATURES WILL OCCUR THROUGH THE
WEEKEND...WHICH MEANS SNOW MELT IS LIKELY THIS WEEKEND. ALSO...A
STORM SYSTEM MOVING ALONG A FRONTAL BOUNDARY MAY BRING SIGNIFICANT
PCPN TO THE FORECAST AREA SAT NIGHT INTO SUNDAY.
TEMPERATURES SUNDAY ARE EXPECTED TO WARM INTO THE 50S OR POSSIBLY
EVEN 60S ACROSS THE EASTERN CATSKILLS...MID HUDSON VALLEY...CENTRAL
AND SOUTHERN TACONICS INTO THE BERKSHIRES AND ACROSS LITCHFIELD
COUNTY WITH 50S ACROSS THE CAPITAL REGION...40S FURTHER NORTH.
BETWEEN THE RAIN AND RUNOFF FROM SNOWMELT DUE TO THE MILD/WARM
TEMPERATURES...SOME FLOODING COULD BE A PROBLEM INCLUDING ICE JAMS
ISSUES. AT THIS POINT...WE BELIEVE MOST IF NOT ALL OF THE SNOW COULD
BE MELTED FROM ABOUT THE MOHAWK RIVER SOUTH. FURTHER NORTH...
TEMPERATURES MIGHT NOT BE WARM ENOUGH TO MELT ALL OF THE SNOW.
THE POTENTIAL IS THERE FOR 1-2.5 INCHES OF RAINFALL FROM ALBANY
NORTHWARD...POSSIBLY SOME AREAS REACHING 3 INCHES. LESSER AMOUNTS OF
RAIN LOOK TO FALL SOUTH OF THE CAPITAL REGION...AN INCH OR LESS.
WILL KEEP MENTION OF IN OUR HAZARDOUS WEATHER OUTLOOK.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...FREEZING RAIN ADVISORY UNTIL 6 AM EST EARLY THIS MORNING FOR
NYZ042-043.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...GJM
NEAR TERM...FRUGIS/GJM/JPV
SHORT TERM...GJM
LONG TERM...JPV
AVIATION...FRUGIS
HYDROLOGY...GJM/NAS
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
851 AM EST SAT DEC 21 2013
.SYNOPSIS...
HIGH PRESSURE OFF THE COAST WILL CIRCULATE WARM AND INCREASINGLY
MOIST AIR INTO THE FORECAST AREA AHEAD OF A SLOW MOVING COLD
FRONT. THE FRONT WILL MOVE THROUGH THE FORECAST AREA MONDAY.
COOL AND DRY HIGH PRESSURE BEHIND THE FRONT WILL DOMINATE TUESDAY
AND WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
INCREASED LOW-LEVEL MOISTURE ASSOCIATED WITH THE SOUTHERLY FLOW ON
THE BACKSIDE OF THE OFFSHORE HIGH PLUS NOCTURNAL COOLING HAS HELPED
CAUSE AREAS OF STRATUS AND FOG THIS MORNING. HEATING AND MIXING
LATER THIS MORNING SHOULD HELP DIMINISH THE LOW CLOUDINESS... BUT
SOME CLOUDINESS SHOULD LINGER THROUGH THE DAY BECAUSE OF
ISENTROPIC LIFT AND CONTINUED UPPER-LEVEL MOISTURE STREAMING INTO
THE AREA IN THE SOUTHWEST FLOW. GENERALLY EXPECT PARTLY CLOUDY OR
MOSTLY CLOUDY SKIES. THE LIFT WILL BE WEAK AND MOISTURE SHALLOW
WITH FORCING ASSOCIATED WITH THE FRONT WELL TO THE WEST. THE
SHOWER CHANCE SHOULD BE LOW. THE HIGH-RESOLUTION MODELS KEEP THE
FORECAST AREA DRY. IT WILL BE WARM AND THE TEMPERATURE GUIDANCE
WAS CONSISTENT DISPLAYING HIGHS IN THE MIDDLE AND UPPER 70S WHICH
WILL BE 15 TO 20 DEGREES ABOVE NORMAL. THE BUFKIT MOMENTUM
TRANSFER TOOL AND HRRR INDICATED WIND GUSTS NEAR 20 KNOTS THIS
AFTERNOON.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/...
TONIGHT...WE WILL REMAIN IN THE SOUTHERLY FLOW ASSOCIATED WITH THE
OFFSHORE HIGH AND COLD FRONT TO OUR WEST. THE MODELS KEEP
ISENTROPIC LIFT WEAK AND MOISTURE SHALLOW. ALL OF THE NAM AND GFS
MOS SUPPORT VERY LOW POPS. WE USED THE WARMER TEMPERATURE GUIDANCE
BECAUSE OF CLOUDINESS AND MIXING. THESE TEMPERATURES WILL BE 20 TO
30 DEGREES ABOVE NORMAL. THE WARMEST DAILY MINIMUM RECORDS FOR THE
DATE WILL BE IN JEOPARDY.
SUNDAY THROUGH MONDAY NIGHT...SURFACE LOW PRESSURE WILL LIFT
NORTHEASTWARD INTO THE GREAT LAKE REGION AND NORTHEAST STATES
SUNDAY AND SUNDAY NIGHT. THE TRAILING COLD FRONT WILL MAKE SLOW
PROGRESS EASTWARD AND TOWARD THE FORECAST AREA BECAUSE OF
SOUTHWESTERLY UPPER-LEVEL FLOW NEARLY PARALLEL TO THE ORIENTATION
OF THE FRONT. STRONG WARM ADVECTION WITH SOUTHWEST H85 WINDS OF 40
TO 45 KNOTS WILL HELP SUPPORT NEAR-RECORD HIGH TEMPERATURES SUNDAY
WITH MAXIMUM READINGS IN THE MID TO UPPER 70S. THE TIMING OF THE
FRONT AND ASSOCIATED PRECIPITATION MAY IMPACT TEMPERATURES MAINLY
IN THE WEST PART OF THE FORECAST AREA SUNDAY.
A SURGE OF MOISTURE ALONG THE FRONT AIDED BY THE H85 JET WILL
RAISE PRECIPITABLE WATER VALUES TO NEAR 1.7 OF AN INCH ACCORDING
TO THE NAM...WHICH IS EXTREMELY HIGH FOR THIS TIME OF YEAR. STRONG
UPPER DYNAMICS WILL ACCOMPANY THE FRONT AS THE REGION FALLS WITHIN
THE RIGHT ENTRANCE REGION OF THE H25 JET. THIS LIFT COMBINED WITH
THE MOISTURE AND POTENTIAL INSTABILITY WILL BRING THE POSSIBLY OF
HEAVY RAIN AND SEVERE WEATHER SUNDAY EVENING AND OVERNIGHT.
THE FRONT WILL BE SLOW TO PUSH ACROSS THE REGION UNTIL THE UPPER
FLOW BECOMES MORE WESTERLY WHICH SHOULD OCCUR MONDAY...AS THE
UPPER TROUGH TO THE WEST SHIFTS EASTWARD ACROSS THE OHIO AND TENNESSEE
VALLEYS. WILL CARRY CATEGORICAL POPS DURING THE SUNDAY NIGHT AND
EARLY MONDAY TIME FRAME. BELIEVE MOST OF THE FORECAST AREA WILL
SEE SIGNIFICANT RAINFALL SUNDAY NIGHT AND MONDAY. THE NAM INDICATED
TOTALS ABOUT 0.6 OF AN INCH AND GFS NEAR 1 INCH. THE 03Z SREF MEAN
WAS AROUND 1.2 OF AN INCH. WE AVERAGED THIS GUIDANCE FOR THE RAINFALL
FORECAST. LEANED TOWARD THE COOLER TEMPERATURE GUIDANCE MONDAY
BECAUSE OF EXPECTED CLOUDINESS AND RAIN PLUS COLD ADVECTION BEHIND
THE FRONT LATER IN THE DAY.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
THE EXTENDED FORECAST FEATURES DRY AND COOL WEATHER FOR CHRISTMAS
EVE AND CHRISTMAS DAY FOLLOWED BY INCREASING MOISTURE AND CHANCES
FOR RAIN BY THE END OF THE WEEK.
THE MEDIUM-RANGE MODELS ARE IN FAIR AGREEMENT SHOWING GENERALLY
ZONAL FLOW TUESDAY AND WEDNESDAY WITH AN 1035 MB SURFACE HIGH
PRESSURE SYSTEM SETTLING OVER THE MID ATLANTIC AND SOUTHEASTERN
STATES. PRECIPITABLE WATER VALUES FALL BELOW A QUARTER OF AN INCH
TUESDAY AND WEDNESDAY AND WILL NOT CARRY ANY POPS DURING THIS
TIME. THE COOL AND DRY AIR MASS UNDER HIGH PRESSURE WILL YIELD
MAXIMUM TEMPERATURES NEAR TO SLIGHTLY BELOW NORMAL IN THE 50S
WHILE LOW TEMPERATURES WILL BE SOME 5 TO 10 DEGREES BELOW NORMAL
WEDNESDAY MORNING AND A FEW DEGREES BELOW NORMAL THURSDAY MORNING.
DEEP UPPER-LEVEL TROUGHING ACROSS THE MIDDLE PART OF THE COUNTRY
THURSDAY INTO FRIDAY IS EXPECTED TO RESULT IN THE DEVELOPMENT OF
A PRESSURE TROUGH OFF THE SOUTHEAST COAST. THERE HAS BEEN MODEL
INCONSISTENCIES WITH THE STRENGTH AND LOCATION OF THE TROUGH AND
ITS ASSOCIATED MOISTURE. WE FORECASTED SLIGHT CHANCE POPS
THURSDAY INTO FRIDAY WHICH WAS SUPPORTED BY THE GFS ENSEMBLE MEAN
POP PLUS THE GFS AND ECMWF MOS. TEMPERATURES FOR THE END OF THE
WEEK SHOULD BE NEAR NORMAL.
&&
.AVIATION /14Z SATURDAY THROUGH WEDNESDAY/...
VFR CONDITIONS FOR MUCH OF THE PERIOD...GIVING WAY TO MVFR/IFR
CONDITIONS AFTER 22/02Z.
PATCHY FOG DEVELOPED OVERNIGHT...HOWEVER WITH THICKENING MID AND
UPPER LEVEL CLOUDS MIGRATING INTO THE AREA THE FOG HAS LESSENED OVER
THE PAST COUPLE OF HOURS. EXPECT VFR CONDITIONS RETURNING TO ALL TAF
SITES BY 15Z. MOISTURE WILL CONTINUE TO INCREASE THROUGH THE
AFTERNOON HOURS WITH CLOUDS CONTINUING TO THICKEN AND LOWER. BY
22/02Z EXPECT CIGS TO BEGIN RAPIDLY LOWERING WITH MVFR EXPECTED WITH
FURTHER LOWERING TO IFR BETWEEN 22/06 AND 22/08Z. WINDS WILL BE
SOUTHERLY AROUND 8 KNOTS THROUGH THE PERIOD.
EXTENDED AVIATION OUTLOOK...CIG/VSBY RESTRICTIONS IN FOG/STRATUS
EXPECTED INTO EARLY SUNDAY MORNING. A COLD FRONT WILL CROSS THE
REGION LATE SUNDAY INTO MONDAY BRINGING SHOWERS...POSSIBLY
THUNDERSTORMS...AND ASSOCIATED RESTRICTIONS.
&&
.CLIMATE...
COLUMBIA
RECORD HIGH TODAY 12/21/13...76 LAST SET IN 1998
RECORD HIGH MINIMUM TONIGHT 12/22/13...60 SET IN 1918
RECORD HIGH SUNDAY 12/22/13...76 LAST SET IN 2011
AUGUSTA BUSH
RECORD HIGH TODAY 12/21/13...79 SET IN 1998
RECORD HIGH MINIMUM TONIGHT 12/22/13...59 SET IN 1898
RECORD HIGH SUNDAY 12/22/13...77 SET IN 2011
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
649 AM EST SAT DEC 21 2013
.SYNOPSIS...
HIGH PRESSURE OFF THE COAST WILL CIRCULATE WARM AND INCREASINGLY
MOIST AIR INTO THE FORECAST AREA AHEAD OF A SLOW MOVING COLD
FRONT. THE FRONT WILL MOVE THROUGH THE FORECAST AREA MONDAY.
COOL AND DRY HIGH PRESSURE BEHIND THE FRONT WILL DOMINATE TUESDAY
AND WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
INCREASED LOW-LEVEL MOISTURE ASSOCIATED WITH THE SOUTHERLY FLOW ON
THE BACKSIDE OF THE OFFSHORE HIGH PLUS NOCTURNAL COOLING HAS HELPED
CAUSE AREAS OF STRATUS AND FOG EARLY THIS MORNING. HEATING AND
MIXING LATER THIS MORNING SHOULD HELP DIMINISH THE LOW CLOUDINESS...
BUT SOME CLOUDINESS SHOULD LINGER THROUGH THE DAY BECAUSE OF
ISENTROPIC LIFT AND CONTINUED UPPER-LEVEL MOISTURE STREAMING INTO
THE AREA IN THE SOUTHWEST FLOW. GENERALLY EXPECT PARTLY CLOUDY OR
MOSTLY CLOUDY SKIES. THE LIFT WILL BE WEAK AND MOISTURE SHALLOW
WITH FORCING ASSOCIATED WITH THE FRONT WELL TO THE WEST. THE
SHOWER CHANCE SHOULD BE LOW. THE HIGH-RESOLUTION MODELS KEEP THE
FORECAST AREA DRY. THE NAM...GFS AND ECMWF MOS INDICATE POPS OF 20
PERCENT OR LESS. IT WILL BE WARM AND THE TEMPERATURE GUIDANCE WAS
CONSISTENT DISPLAYING HIGHS IN THE MIDDLE AND UPPER 70S WHICH WILL
BE 15 TO 20 DEGREES ABOVE NORMAL. THE BUFKIT MOMENTUM TRANSFER
TOOL AND HRRR INDICATED WIND GUSTS NEAR 20 KNOTS THIS AFTERNOON.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/...
TONIGHT...WE WILL REMAIN IN THE SOUTHERLY FLOW ASSOCIATED WITH THE
OFFSHORE HIGH AND COLD FRONT TO OUR WEST. THE MODELS KEEP
ISENTROPIC LIFT WEAK AND MOISTURE SHALLOW. ALL OF THE NAM AND GFS
MOS SUPPORT VERY LOW POPS. WE USED THE WARMER TEMPERATURE GUIDANCE
BECAUSE OF CLOUDINESS AND MIXING. THESE TEMPERATURES WILL BE 20 TO
30 DEGREES ABOVE NORMAL. THE WARMEST DAILY MINIMUM RECORDS FOR THE
DATE WILL BE IN JEOPARDY.
SUNDAY THROUGH MONDAY NIGHT...SURFACE LOW PRESSURE WILL LIFT
NORTHEASTWARD INTO THE GREAT LAKE REGION AND NORTHEAST STATES
SUNDAY AND SUNDAY NIGHT. THE TRAILING COLD FRONT WILL MAKE SLOW
PROGRESS EASTWARD AND TOWARD THE FORECAST AREA BECAUSE OF
SOUTHWESTERLY UPPER-LEVEL FLOW NEARLY PARALLEL TO THE ORIENTATION
OF THE FRONT. STRONG WARM ADVECTION WITH SOUTHWEST H85 WINDS OF 40
TO 45 KNOTS WILL HELP SUPPORT NEAR-RECORD HIGH TEMPERATURES SUNDAY
WITH MAXIMUM READINGS IN THE MID TO UPPER 70S. THE TIMING OF THE
FRONT AND ASSOCIATED PRECIPITATION MAY IMPACT TEMPERATURES MAINLY
IN THE WEST PART OF THE FORECAST AREA SUNDAY.
A SURGE OF MOISTURE ALONG THE FRONT AIDED BY THE H85 JET WILL
RAISE PRECIPITABLE WATER VALUES TO NEAR 1.7 OF AN INCH ACCORDING
TO THE NAM...WHICH IS EXTREMELY HIGH FOR THIS TIME OF YEAR. STRONG
UPPER DYNAMICS WILL ACCOMPANY THE FRONT AS THE REGION FALLS WITHIN
THE RIGHT ENTRANCE REGION OF THE H25 JET. THIS LIFT COMBINED WITH
THE MOISTURE AND POTENTIAL INSTABILITY WILL BRING THE POSSIBLY OF
HEAVY RAIN AND SEVERE WEATHER SUNDAY EVENING AND OVERNIGHT.
THE FRONT WILL BE SLOW TO PUSH ACROSS THE REGION UNTIL THE UPPER
FLOW BECOMES MORE WESTERLY WHICH SHOULD OCCUR MONDAY...AS THE
UPPER TROUGH TO THE WEST SHIFTS EASTWARD ACROSS THE OHIO AND TENNESSEE
VALLEYS. WILL CARRY CATEGORICAL POPS DURING THE SUNDAY NIGHT AND
EARLY MONDAY TIME FRAME. BELIEVE MOST OF THE FORECAST AREA WILL
SEE SIGNIFICANT RAINFALL SUNDAY NIGHT AND MONDAY. THE NAM INDICATED
TOTALS ABOUT 0.6 OF AN INCH AND GFS NEAR 1 INCH. THE 03Z SREF MEAN
WAS AROUND 1.2 OF AN INCH. WE AVERAGED THIS GUIDANCE FOR THE RAINFALL
FORECAST. LEANED TOWARD THE COOLER TEMPERATURE GUIDANCE MONDAY
BECAUSE OF EXPECTED CLOUDINESS AND RAIN PLUS COLD ADVECTION BEHIND
THE FRONT LATER IN THE DAY.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
THE EXTENDED FORECAST FEATURES DRY AND COOL WEATHER FOR CHRISTMAS
EVE AND CHRISTMAS DAY FOLLOWED BY INCREASING MOISTURE AND CHANCES
FOR RAIN BY THE END OF THE WEEK.
THE MEDIUM-RANGE MODELS ARE IN FAIR AGREEMENT SHOWING GENERALLY
ZONAL FLOW TUESDAY AND WEDNESDAY WITH AN 1035 MB SURFACE HIGH
PRESSURE SYSTEM SETTLING OVER THE MID ATLANTIC AND SOUTHEASTERN
STATES. PRECIPITABLE WATER VALUES FALL BELOW A QUARTER OF AN INCH
TUESDAY AND WEDNESDAY AND WILL NOT CARRY ANY POPS DURING THIS
TIME. THE COOL AND DRY AIR MASS UNDER HIGH PRESSURE WILL YIELD
MAXIMUM TEMPERATURES NEAR TO SLIGHTLY BELOW NORMAL IN THE 50S
WHILE LOW TEMPERATURES WILL BE SOME 5 TO 10 DEGREES BELOW NORMAL
WEDNESDAY MORNING AND A FEW DEGREES BELOW NORMAL THURSDAY MORNING.
DEEP UPPER-LEVEL TROUGHING ACROSS THE MIDDLE PART OF THE COUNTRY
THURSDAY INTO FRIDAY IS EXPECTED TO RESULT IN THE DEVELOPMENT OF
A PRESSURE TROUGH OFF THE SOUTHEAST COAST. THERE HAS BEEN MODEL
INCONSISTENCIES WITH THE STRENGTH AND LOCATION OF THE TROUGH AND
ITS ASSOCIATED MOISTURE. WE FORECASTED SLIGHT CHANCE POPS
THURSDAY INTO FRIDAY WHICH WAS SUPPORTED BY THE GFS ENSEMBLE MEAN
POP PLUS THE GFS AND ECMWF MOS. TEMPERATURES FOR THE END OF THE
WEEK SHOULD BE NEAR NORMAL.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
VFR CONDITIONS FOR MUCH OF THE PERIOD...GIVING WAY TO MVFR/IFR
CONDITIONS AFTER 22/02Z.
PATCHY FOG DEVELOPED OVERNIGHT...HOWEVER WITH THICKENING MID AND
UPPER LEVEL CLOUDS MIGRATING INTO THE AREA THE FOG HAS LESSENED
OVER THE PAST COUPLE OF HOURS. EXPECT REMAINING FOG TO DISSIPATE
WITH SUNRISE AND ALL SITES RETURNING TO VFR BY 13Z. MOISTURE WILL
CONTINUE TO INCREASE THROUGH THE AFTERNOON HOURS WITH CLOUDS
CONTINUING TO THICKEN AND LOWER. BY 22/02Z EXPECT CIGS TO BEGIN
RAPIDLY LOWERING WITH MVFR EXPECTED WITH FURTHER LOWERING TO IFR
BETWEEN 22/06 AND 22/08Z. WINDS WILL BE SOUTHERLY AROUND 8 KNOTS
THROUGH THE PERIOD.
EXTENDED AVIATION OUTLOOK...CIG/VSBY RESTRICTIONS IN FOG/STRATUS
EXPECTED INTO EARLY SUNDAY MORNING. A COLD FRONT WILL CROSS THE
REGION LATE SUNDAY INTO MONDAY BRINGING SHOWERS...POSSIBLY
THUNDERSTORMS...AND ASSOCIATED RESTRICTIONS.
&&
.CLIMATE...
COLUMBIA
RECORD HIGH TODAY 12/21/13...76 LAST SET IN 1998
RECORD HIGH MINIMUM TONIGHT 12/22/13...60 SET IN 1918
RECORD HIGH SUNDAY 12/22/13...76 LAST SET IN 2011
AUGUSTA BUSH
RECORD HIGH TODAY 12/21/13...79 SET IN 1998
RECORD HIGH MINIMUM TONIGHT 12/22/13...59 SET IN 1898
RECORD HIGH SUNDAY 12/22/13...77 SET IN 2011
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
600 AM EST SAT DEC 21 2013
.SYNOPSIS...
HIGH PRESSURE OFF THE COAST WILL CIRCULATE WARM AND INCREASINGLY
MOIST AIR INTO THE FORECAST AREA AHEAD OF A SLOW MOVING COLD
FRONT. THE FRONT WILL MOVE THROUGH THE FORECAST AREA MONDAY.
COOL AND DRY HIGH PRESSURE BEHIND THE FRONT WILL DOMINATE TUESDAY
AND WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
INCREASED LOW-LEVEL MOISTURE ASSOCIATED WITH THE SOUTHERLY FLOW ON
THE BACKSIDE OF THE OFFSHORE HIGH PLUS NOCTURNAL COOLING HAS HELPED
CAUSE AREAS OF STRATUS AND FOG EARLY THIS MORNING. HEATING AND
MIXING LATER THIS MORNING SHOULD HELP DIMINISH THE LOW CLOUDINESS...
BUT SOME CLOUDINESS SHOULD LINGER THROUGH THE DAY BECAUSE OF
ISENTROPIC LIFT AND CONTINUED UPPER-LEVEL MOISTURE STREAMING INTO
THE AREA IN THE SOUTHWEST FLOW. GENERALLY EXPECT PARTLY CLOUDY OR
MOSTLY CLOUDY SKIES. THE LIFT WILL BE WEAK AND MOISTURE SHALLOW
WITH FORCING ASSOCIATED WITH THE FRONT WELL TO THE WEST. THE
SHOWER CHANCE SHOULD BE LOW. THE HIGH-RESOLUTION MODELS KEEP THE
FORECAST AREA DRY. THE NAM...GFS AND ECMWF MOS INDICATE POPS OF 20
PERCENT OR LESS. IT WILL BE WARM AND THE TEMPERATURE GUIDANCE WAS
CONSISTENT DISPLAYING HIGHS IN THE MIDDLE AND UPPER 70S WHICH WILL
BE 15 TO 20 DEGREES ABOVE NORMAL. THE BUFKIT MOMENTUM TRANSFER
TOOL AND HRRR INDICATED WIND GUSTS NEAR 20 KNOTS THIS AFTERNOON.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/...
TONIGHT...WE WILL REMAIN IN THE SOUTHERLY FLOW ASSOCIATED WITH THE
OFFSHORE HIGH AND COLD FRONT TO OUR WEST. THE MODELS KEEP
ISENTROPIC LIFT WEAK AND MOISTURE SHALLOW. ALL OF THE NAM AND GFS
MOS SUPPORT VERY LOW POPS. WE USED THE WARMER TEMPERATURE GUIDANCE
BECAUSE OF CLOUDINESS AND MIXING. THESE TEMPERATURES WILL BE 20 TO
30 DEGREES ABOVE NORMAL. THE WARMEST DAILY MINIMUM RECORDS FOR THE
DATE WILL BE IN JEOPARDY.
SUNDAY THROUGH MONDAY NIGHT...SURFACE LOW PRESSURE WILL LIFT
NORTHEASTWARD INTO THE GREAT LAKE REGION AND NORTHEAST STATES
SUNDAY AND SUNDAY NIGHT. THE TRAILING COLD FRONT WILL MAKE SLOW
PROGRESS EASTWARD AND TOWARD THE FORECAST AREA BECAUSE OF
SOUTHWESTERLY UPPER-LEVEL FLOW NEARLY PARALLEL TO THE ORIENTATION
OF THE FRONT. STRONG WARM ADVECTION WITH SOUTHWEST H85 WINDS OF 40
TO 45 KNOTS WILL HELP SUPPORT NEAR-RECORD HIGH TEMPERATURES SUNDAY
WITH MAXIMUM READINGS IN THE MID TO UPPER 70S. THE TIMING OF THE
FRONT AND ASSOCIATED PRECIPITATION MAY IMPACT TEMPERATURES MAINLY
IN THE WEST PART OF THE FORECAST AREA SUNDAY.
A SURGE OF MOISTURE ALONG THE FRONT AIDED BY THE H85 JET WILL
RAISE PRECIPITABLE WATER VALUES TO NEAR 1.7 OF AN INCH ACCORDING
TO THE NAM...WHICH IS EXTREMELY HIGH FOR THIS TIME OF YEAR. STRONG
UPPER DYNAMICS WILL ACCOMPANY THE FRONT AS THE REGION FALLS WITHIN
THE RIGHT ENTRANCE REGION OF THE H25 JET. THIS LIFT COMBINED WITH
THE MOISTURE AND POTENTIAL INSTABILITY WILL BRING THE POSSIBLY OF
HEAVY RAIN AND SEVERE WEATHER SUNDAY EVENING AND OVERNIGHT.
THE FRONT WILL BE SLOW TO PUSH ACROSS THE REGION UNTIL THE UPPER
FLOW BECOMES MORE WESTERLY WHICH SHOULD OCCUR MONDAY...AS THE
UPPER TROUGH TO THE WEST SHIFTS EASTWARD ACROSS THE OHIO AND TENNESSEE
VALLEYS. WILL CARRY CATEGORICAL POPS DURING THE SUNDAY NIGHT AND
EARLY MONDAY TIME FRAME. BELIEVE MOST OF THE FORECAST AREA WILL
SEE SIGNIFICANT RAINFALL SUNDAY NIGHT AND MONDAY. THE NAM INDICATED
TOTALS ABOUT 0.6 OF AN INCH AND GFS NEAR 1 INCH. THE 03Z SREF MEAN
WAS AROUND 1.2 OF AN INCH. WE AVERAGED THIS GUIDANCE FOR THE RAINFALL
FORECAST. LEANED TOWARD THE COOLER TEMPERATURE GUIDANCE MONDAY
BECAUSE OF EXPECTED CLOUDINESS AND RAIN PLUS COLD ADVECTION BEHIND
THE FRONT LATER IN THE DAY.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
THE EXTENDED FORECAST FEATURES DRY AND COOL WEATHER FOR CHRISTMAS
EVE AND CHRISTMAS DAY FOLLOWED BY INCREASING MOISTURE AND CHANCES
FOR RAIN BY THE END OF THE WEEK.
THE MEDIUM-RANGE MODELS ARE IN FAIR AGREEMENT SHOWING GENERALLY
ZONAL FLOW TUESDAY AND WEDNESDAY WITH AN 1035 MB SURFACE HIGH
PRESSURE SYSTEM SETTLING OVER THE MID ATLANTIC AND SOUTHEASTERN
STATES. PRECIPITABLE WATER VALUES FALL BELOW A QUARTER OF AN INCH
TUESDAY AND WEDNESDAY AND WILL NOT CARRY ANY POPS DURING THIS
TIME. THE COOL AND DRY AIR MASS UNDER HIGH PRESSURE WILL YIELD MAXIMUM
TEMPERATURES NEAR TO SLIGHTLY BELOW NORMAL IN THE 50S WHILE LOW
TEMPERATURES WILL BE SOME 5 TO 10 DEGREES BELOW NORMAL WEDNESDAY
MORNING AND A FEW DEGREES BELOW NORMAL THURSDAY MORNING.
DEEP UPPER-LEVEL TROUGHING ACROSS THE MIDDLE PART OF THE COUNTRY
THURSDAY INTO FRIDAY IS EXPECTED TO RESULT IN THE DEVELOPMENT OF
A PRESSURE TROUGH OFF THE SOUTHEAST COAST. THERE HAS BEEN MODEL
INCONSISTENCIES WITH THE STRENGTH AND LOCATION OF THE TROUGH AND
ITS ASSOCIATED MOISTURE. WE FORECASTED SLIGHT CHANCE POPS
THURSDAY INTO FRIDAY WHICH WAS SUPPORTED BY THE GFS ENSEMBLE MEAN
POP PLUS THE GFS AND ECMWF MOS. TEMPERATURES FOR THE END OF THE
WEEK SHOULD BE NEAR NORMAL.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
LOW CONFIDENCE REGARDING CIG/VSBY RESTRICTIONS EARLY THIS MORNING.
CLOUDS CONTINUE TO INCREASE FROM THE WEST AS WITH PATCHY FOG
BEGINNING TO FORM. LOW AND MID CLOUDS HAVE MOVED INTO EASTERN GA
WHICH WILL WORK TO LESSEN FOG POTENTIAL...HOWEVER WITH FOG
ALREADY DEVELOPING POTENTIAL FOR FOG REMAINS MODERATE AND THUS
CONFIDENCE REMAINS LOW DUE TO TIMING ISSUES. HAVE REMAINED WITH
MVFR FOG FOR CAE/CUB/DNL WITH IFR/LIFR FOR AGS/OGB. FOG WILL ERODE
AFTER SUNRISE AND ONSET OF MIXING WITH REMAINDER OF THE PERIOD
VFR. WINDS WILL BE LIGHT AND VARIABLE THROUGH MID MORNING THEN
BECOME SOUTHWESTERLY AROUND 10 KNOTS THROUGH THE END OF THE
PERIOD.
EXTENDED AVIATION OUTLOOK...CIG/VSBY RESTRICTIONS IN FOG/STRATUS
EXPECTED LATE SATURDAY NIGHT INTO EARLY SUNDAY MORNING. A COLD
FRONT WILL CROSS THE REGION LATE SUNDAY INTO MONDAY BRINGING
SHOWERS...POSSIBLY THUNDERSTORMS...AND ASSOCIATED RESTRICTIONS.
&&
.CLIMATE...
COLUMBIA
RECORD HIGH TODAY 12/21/13...76 LAST SET IN 1998
RECORD HIGH MINIMUM TONIGHT 12/22/13...60 SET IN 1918
RECORD HIGH SUNDAY 12/22/13...76 LAST SET IN 2011
AUGUSTA BUSH
RECORD HIGH TODAY 12/21/13...79 SET IN 1998
RECORD HIGH MINIMUM TONIGHT 12/22/13...59 SET IN 1898
RECORD HIGH SUNDAY 12/22/13...77 SET IN 2011
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
340 AM EST SAT DEC 21 2013
.SYNOPSIS...
HIGH PRESSURE OFF THE COAST WILL CIRCULATE WARM AND INCREASINGLY
MOIST AIR INTO THE FORECAST AREA AHEAD OF A SLOW MOVING COLD
FRONT. THE FRONT WILL MOVE THROUGH THE FORECAST AREA MONDAY.
COOL AND DRY HIGH PRESSURE BEHIND THE FRONT WILL DOMINATE TUESDAY
AND WEDNESDAY.
&&
.NEAR TERM /THROUGH TODAY/...
INCREASED LOW-LEVEL MOISTURE ASSOCIATED WITH THE SOUTHERLY FLOW ON
THE BACKSIDE OF THE OFFSHORE HIGH PLUS NOCTURNAL COOLING SHOULD
HELP SUPPORT CONSIDERABLE STRATUS AND FOG EARLY THIS MORNING.
STRATUS SHOULD BE FAVORED BECAUSE OF SIGNIFICANT BOUNDARY-LAYER
WIND. HEATING AND MIXING LATER THIS MORNING SHOULD HELP DIMINISH
SOME OF THIS CLOUDINESS...BUT CLOUDINESS SHOULD LINGER THROUGH
THE DAY BECAUSE OF ISENTROPIC LIFT AND CONTINUED UPPER-LEVEL
MOISTURE STREAMING INTO THE AREA IN THE SOUTHWEST FLOW. GENERALLY
EXPECT PARTLY CLOUDY OR MOSTLY CLOUDY SKIES. THE LIFT WILL BE WEAK
AND MOISTURE SHALLOW WITH FORCING ASSOCIATED WITH THE FRONT WELL
TO THE WEST. THE SHOWER CHANCE SHOULD BE LOW. THE HIGH-RESOLUTION
MODELS KEEP THE FORECAST AREA DRY. THE NAM...GFS AND ECMWF MOS
INDICATE POPS OF 20 PERCENT OR LESS. IT WILL BE WARM AND THE
TEMPERATURE GUIDANCE WAS CONSISTENT DISPLAYING HIGHS IN THE MIDDLE
AND UPPER 70S WHICH WILL BE 15 TO 20 DEGREES ABOVE NORMAL. THE
BUFKIT MOMENTUM TRANSFER TOOL AND HRRR INDICATED WIND GUSTS NEAR
20 KNOTS THIS AFTERNOON.
&&
.SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
TONIGHT...WE WILL REMAIN IN THE SOUTHERLY FLOW ASSOCIATED WITH THE
OFFSHORE HIGH AND COLD FRONT TO OUR WEST. THE MODELS KEEP
ISENTROPIC LIFT WEAK AND MOISTURE SHALLOW. ALL OF THE NAM AND GFS
MOS SUPPORT VERY LOW POPS. WE USED THE WARMER TEMPERATURE
GUIDANCE BECAUSE OF CLOUDINESS AND MIXING. THESE TEMPERATURES WILL
BE 20 TO 30 DEGREES ABOVE NORMAL. THE WARMEST DAILY MINIMUM
RECORDS FOR THE DATE WILL BE IN JEOPARDY.
SUNDAY THROUGH MONDAY NIGHT...SURFACE LOW PRESSURE WILL LIFT
NORTHEASTWARD INTO THE GREAT LAKE REGION AND NORTHEAST STATES
SUNDAY AND SUNDAY NIGHT. THE TRAILING COLD FRONT WILL MAKE SLOW
PROGRESS EASTWARD AND TOWARD THE FORECAST AREA BECAUSE OF
SOUTHWESTERLY UPPER-LEVEL FLOW NEARLY PARALLEL TO THE ORIENTATION
OF THE FRONT. STRONG WARM ADVECTION WITH SOUTHWEST H85 WINDS OF 40
TO 45 KNOTS WILL HELP SUPPORT NEAR-RECORD HIGH TEMPERATURES SUNDAY
WITH MAXIMUM READINGS IN THE MID TO UPPER 70S. THE TIMING OF THE
FRONT AND ASSOCIATED PRECIPITATION MAY IMPACT TEMPERATURES MAINLY
IN THE WEST PART OF THE FORECAST AREA SUNDAY.
A SURGE OF MOISTURE ALONG THE FRONT AIDED BY THE H85 JET WILL
RAISE PRECIPITABLE WATER VALUES TO NEAR 1.7 OF AN INCH ACCORDING
TO THE NAM...WHICH IS EXTREMELY HIGH FOR THIS TIME OF YEAR. STRONG
UPPER DYNAMICS WILL ACCOMPANY THE FRONT AS THE REGION FALLS WITHIN
THE RIGHT ENTRANCE REGION OF THE H25 JET. THIS LIFT COMBINED WITH
THE MOISTURE AND POTENTIAL INSTABILITY WILL BRING THE POSSIBLY OF
HEAVY RAIN AND SEVERE WEATHER SUNDAY EVENING AND OVERNIGHT.
THE FRONT WILL BE SLOW TO PUSH ACROSS THE REGION UNTIL THE UPPER
FLOW BECOMES MORE WESTERLY WHICH SHOULD OCCUR MONDAY...AS THE
UPPER TROUGH TO THE WEST SHIFTS EASTWARD ACROSS THE OHIO AND TENNESSEE
VALLEYS. WILL CARRY CATEGORICAL POPS DURING THE SUNDAY NIGHT AND
EARLY MONDAY TIME FRAME. BELIEVE MOST OF THE FORECAST AREA WILL
SEE SIGNIFICANT RAINFALL SUNDAY NIGHT AND MONDAY. THE NAM INDICATED
TOTALS ABOUT 0.6 OF AN INCH AND GFS NEAR 1 INCH. THE 03Z SREF MEAN
WAS AROUND 1.2 OF AN INCH. WE AVERAGED THIS GUIDANCE FOR THE RAINFALL
FORECAST. LEANED TOWARD THE COOLER TEMPERATURE GUIDANCE MONDAY
BECAUSE OF EXPECTED CLOUDINESS AND RAIN PLUS COLD ADVECTION BEHIND
THE FRONT LATER IN THE DAY.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
THE EXTENDED FORECAST FEATURES DRY AND COOL WEATHER FOR CHRISTMAS
EVE AND CHRISTMAS DAY FOLLOWED BY INCREASING MOISTURE AND CHANCES
FOR RAIN BY THE END OF THE WEEK.
THE MEDIUM-RANGE MODELS ARE IN FAIR AGREEMENT SHOWING GENERALLY
ZONAL FLOW TUESDAY AND WEDNESDAY WITH AN 1035 MB SURFACE HIGH
PRESSURE SYSTEM SETTLING OVER THE MID ATLANTIC AND SOUTHEASTERN
STATES. PRECIPITABLE WATER VALUES FALL BELOW A QUARTER OF AN INCH
TUESDAY AND WEDNESDAY AND WILL NOT CARRY ANY POPS DURING THIS
TIME. THE COOL AND DRY AIR MASS UNDER HIGH PRESSURE WILL YIELD MAXIMUM
TEMPERATURES NEAR TO SLIGHTLY BELOW NORMAL IN THE 50S WHILE LOW
TEMPERATURES WILL BE SOME 5 TO 10 DEGREES BELOW NORMAL WEDNESDAY
MORNING AND A FEW DEGREES BELOW NORMAL THURSDAY MORNING.
DEEP UPPER-LEVEL TROUGHING ACROSS THE MIDDLE PART OF THE COUNTRY
THURSDAY INTO FRIDAY IS EXPECTED TO RESULT IN THE DEVELOPMENT OF
A PRESSURE TROUGH OFF THE SOUTHEAST COAST. THERE HAS BEEN MODEL
INCONSISTENCIES WITH THE STRENGTH AND LOCATION OF THE TROUGH AND
ITS ASSOCIATED MOISTURE. WE FORECASTED SLIGHT CHANCE POPS
THURSDAY INTO FRIDAY WHICH WAS SUPPORTED BY THE GFS ENSEMBLE MEAN
POP PLUS THE GFS AND ECMWF MOS. TEMPERATURES FOR THE END OF THE
WEEK SHOULD BE NEAR NORMAL.
&&
.AVIATION /07Z SATURDAY THROUGH WEDNESDAY/...
LOW CONFIDENCE REGARDING CIG/VSBY RESTRICTIONS LATE TONIGHT/EARLY
SATURDAY MORNING.
CLOUDS CONTINUE TO INCREASE FROM THE WEST AS WITH PATCHY FOG
BEGINNING TO FORM. LOW AND MID CLOUDS HAVE MOVED INTO EASTERN GA
WHICH WILL WORK TO LESSEN FOG POTENTIAL OVERNIGHT...HOWEVER WITH
FOG ALREADY DEVELOPING POTENTIAL FOR FOG REMAINS MODERATE AND THUS
CONFIDENCE REMAINS LOW DUE TO TIMING ISSUES. HAVE REMAINED WITH
MVFR FOG FOR CAE/CUB/DNL WITH IFR/LIFR FOR AGS/OGB. FOG WILL ERODE
WITH SUNRISE AND ONSET OF MIXING WITH REMAINDER OF THE PERIOD VFR.
WINDS WILL BE LIGHT AND VARIABLE THROUGH MID MORNING THEN BECOME
SOUTHWESTERLY AROUND 10 KNOTS THROUGH THE END OF THE PERIOD.
EXTENDED AVIATION OUTLOOK...CIG/VSBY RESTRICTIONS IN FOG/STRATUS
EXPECTED LATE SATURDAY NIGHT INTO EARLY SUNDAY MORNING. A COLD
FRONT WILL CROSS THE REGION LATE SUNDAY INTO MONDAY BRINGING
SHOWERS...POSSIBLY THUNDERSTORMS...AND ASSOCIATED RESTRICTIONS.
&&
.CLIMATE
COLUMBIA
RECORD HIGH TODAY 12/21/13...76 LAST SET IN 1998
RECORD HIGH MINIMUM TONIGHT 12/22/13...60 SET IN 1918
RECORD HIGH SUNDAY 12/22/13...76 LAST SET IN 2011
AUGUSTA BUSH
RECORD HIGH TODAY 12/21/13...79 SET IN 1998
RECORD HIGH MINIMUM TONIGHT 12/22/13...59 SET IN 1898
RECORD HIGH SUNDAY 12/22/13...77 SET IN 2011
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
858 PM CST SUN DEC 22 2013
.DISCUSSION...
745 PM CST
MINOR CHANGES MADE TO THE TONIGHT/S FORECAST....FOR FLURRIES/LIGHT
SNOW TRENDS THIS EVENING AND TO OVERNIGHT LOWS.
THE LATEST SHORT WAVE TROUGH TO AFFECT THE AREA WAS OVER SW WI
AND NE IA EARLY THIS EVENING AND IS PROGGED TO MOVE ACROSS THE
LOCAL AREA DURING THE LATER EVENING AND FIRST PART OF THE
OVERNIGHT HOURS. THIS DISTURBANCE HAS BEEN PRODUCING LIGHT SNOW
AND FLURRIES WHICH HAVE SPREAD FROM N CENTRAL TO NE IL OVER THE
LAST FEW HRS. VISIBILITY HAD BEEN REDUCED TO 2 1/2 TO 4 MI
OVER PORTIONS OF SOUTHERN WI BUT MINIMAL IF ANY REDUCTION IN
VISIBILITY REPORTED S OF THE STATE LINE. FLURRIES ARE EXPECTED
ACROSS MUCH OF THE FORECAST AREA THIS EVENING WHILE THE POTENTIAL
FOR LIGHT SNOW OF ANY CONSEQUENCE N OF I-80 AND INCREASING AS ONE
GETS CLOSER TO THE WI STATE LINE. EVEN THEN AMOUNTS OF NEW
SNOWFALL WILL BE A 1/2 INCH OR LESS...GENERALLY ONLY A TENTH OR
TWO.
REGARDING OVERNIGHT LOWS...AT 01Z TEMPERATURES QUICKLY DROPPED
OFF FROM AROUND 20 ALONG THE MS RIVER TO SINGLE DIGITS IN N
CENTRAL IA AND SW MN. SOME OF THIS IS DUE TO CLEARING OF THE
LOWER CLOUDS FROM OVER PARTS OF THAT AREA BUT EVEN DURING THE
AFTERNOON TEMPERATURES WERE ONLY IN THE 7 TO 14 DEG RANGE. LATEST
PROGS OF SFC...BL AND OTHER LOW LEVEL TEMPS SHOW THIS COLD AIR
ADVECTING E SLIGHTLY DEEPER OVER THE W PORTION OF THE FORECAST
AREA BY SUNRISE. THUS...HAVE SHAVED MAYBE A DEG OR SO OFF OF
LOWS ACROSS THE FAR WESTERN COUNTIES.
//PREV DISCUSSION...
326 PM CST
AS THE LATEST BOUT OF WINTER WEATHER WINDS DOWN...THE MAIN FOCUS FOR
THE NEXT SEVERAL DAYS WILL BE THE TEMPERATURE TRENDS.
HOWEVER...FOR THE REMAINDER OF THE AFTERNOON AND THROUGH THE
OVERNIGHT HOURS...THE CHANCES FOR PCPN ARE NOT TOTALLY OVER. THIS
AFTERNOON...A MID LEVEL DRY SLOT HAS CAPPED THE DEEP LAYER MOISTURE
FROM THE TOP WHILE COLD...DRY ADVECTION HAS DECREASED MOISTURE AT
THE SURFACE. THIS HAS LEFT A SHALLOW ZONE OF SATURATION THAT WILL
NOT BE DEEP ENOUGH INTO THE COLD AIR ALOFT TO GENERATE ANY ICE
PRODUCTION...LIMITING THE PCPN POTENTIAL TO DRIZZLE. AT THE
SURFACE...THE DRY ADVECTION HAS DECREASED DEWPOINTS ENOUGH THAT ANY
DRIZZLE THAT FALLS FROM THE SHALLOW CLOUD DECK WILL NOT REACH THE
GROUND. SO...WITH TEMPERATURES DROPPING BELOW FREEZING THROUGH THE
AFTERNOON WITH THE PERSISTENT COLD ADVECTION AT THE SURFACE...THE
POTENTIAL FOR ANY FREEZING DRIZZLE IS MINIMAL. THE OTHER OF
ADDITIONAL PCPN WILL COME THIS EVENING AND OVERNIGHT AS A NRN STREAM
SHORTWAVE DROPPING OUT OF THE NORTHERN PLAINS REINFORCES A SECONDARY
COLD FRONT DROPPING SOUTH THROUGH WISCONSIN. WITH DEEP LAYER
MOISTURE ON A DECREASING TREND AS THE STRONG SOUTHERN STREAM SYSTEM
MOVES OFF TO THE EAST...THE ENHANCED DYNAMICS FROM THE SHORTWAVE AND
SFC CONVERGENCE FROM THE COLD FRONT WILL ONLY BE SUFFICIENT TO
GENERATE A LITTLE LIGHT SNOW...WITH MINOR ADDITIONAL
ACCUMULATIONS...GENERALLY AROUND A COUPLE TENTHS OF AN INCH...
ESPECIALLY FOR THE NORTHERN PORTIONS OF THE CWA. THE SOUTHERN
PORTIONS OF THE CWA SHOULD SEE LITTLE OR NO ACCUMULATION. THROUGH
THE DAY TOMORROW...THE MAIN LONGWAVE UPPER TROUGH WILL MOVE THROUGH
THE MIDWEST AND WESTERN GREAT LAKES REGIONS...KEEPING A CHANCE FOR
SOME FLURRIES POSSIBLE THROUGH MUCH OF THE DAY TOMORROW. AS THE
UPPER TROUGH MOVES ACROSS THE AREA...COLD ARCTIC HIGH PRESSURE WILL
BUILD ACROSS THE NORTHERN PLAINS AND INTO THE MIDDLE MISSISSIPPI
VALLEY. THIS WILL BE THE FIRST IN A SERIES OF ARCTIC AIR INTRUSIONS
INTO THE REGION. BY MONDAY MORNING...TEMPERATURES SHOULD DROP INTO
THE SINGLE DIGITS WEST OF THE I-39 CORRIDOR WITH THE SLIGHTLY WARMER
AIR HANGING IN TO THE EAST. UNDER A PERSISTENT FETCH OF ARCTIC
AIR...THERE WILL BE LITTLE DIURNAL WARMING THROUGH THE DAY ON MONDAY
WITH HIGHS TOPPING OUT AT 10-15F WEST OF THE FOX VALLEY AND I-55
CORRIDOR WHILE TO THE EAST...TEMPERATURES REMAIN STEADY THROUGH THE
DAY IN THE LOW 20S.
INTO TUESDAY MORNING...AS SFC HIGH PRESSURE BUILDS ACROSS THE
MISSISSIPPI VALLEY WITH THE CENTER OF THE HIGH MOVING THROUGH
SOUTHERN IL...TEMPERATURES WILL DROP BELOW ZERO ALONG AND WEST OF A
WAUKEGAN TO PONTIAC LINE...INCLUDING THE ROCKFORD METRO AREA...WHILE
TEMPS TO THE EAST OF THIS LINE WILL DROP INTO THE LOWER SINGLE
DIGITS...INCLUDING THE CHICAGO METRO AREA. WEST WINDS OF 5 TO 10
MPH WILL BE SUFFICIENT TO CAUSE DANGEROUSLY COLD WIND CHILL READING
WITH THE ROCKFORD TO PONTIAC AREA POSSIBLE REACHING WIND CHILL
ADVISORY LEVELS OF -20F TO -25F. THE REST OF TUESDAY WILL REMAIN
QUITE COLD FOR LAST MINUTE CHRISTMAS SHOPPING AS HIGHS WILL RANGE
FROM THE SINGLE DIGITS OVER THE ROCKFORD AREA TO THE LOWER TO MIDDLE
TEENS OVER THE CHICAGO METRO AREA AND NORTHWESTERN INDIANA.
FOR THE NEXT SEVERAL DAYS...THE LONG WAVE UPPER LEVEL PATTERN WILL
REMAIN VERY HIGH AMPLITUDE AND PROGRESSIVE. THIS PATTERN WILL LEAD
TO RAPIDLY SWINGING PERIODS OF RELATIVE WARMING AND DRASTIC
COOLING. FOR CHRISTMAS EVEN INTO CHRISTMAS DAY...A STRONG SHORTWAVE
DROPPING OUT OF THE NORTHERN PLAINS WILL BRING ANOTHER CHANCE FOR
SOME LIGHT SNOW TO THE REGION. THIS WILL BE THE FIRST IN A SERIES
OF CLIPPER-TYPE SYSTEMS SOURCED FROM THE ARCTIC REGION. THESE
CLIPPER TYPE SYSTEMS...INCLUDING THE ONE EXPECTED TO IMPACT THE
REGION FOR CHRISTMAS EVE AND THROUGH CHRISTMAS DAY TYPICALLY HAVE
LITTLE DEEP LAYER MOISTURE TO WORK WITH AND THUS RELY ON UPPER
DYNAMICS TO GENERATE SNOWFALL. THIS SYSTEM WILL BE A FAIRLY TYPICAL
CLIPPER AND THE REGION COULD BRING PERHAPS 1 TO 2 INCHES.
FOLLOWING A PERIOD OF RELATIVE "WARMTH" ON WEDNESDAY WITH HIGHS IN
THE MIDDLE TO UPPER 20S OVER THE NORTHERN PORTIONS OF THE CWA TO THE
LOW 30S OVER THE SOUTHERN LOCATIONS...ANOTHER SHOT OF ARCTIC AIR
WILL MOVE IN WEDNESDAY NIGHT THROUGH FRIDAY. THE COLDEST PERIOD
WILL BE FRIDAY MORNING WHEN...ONCE AGAIN...THE NORTHWESTERN HALF OF
THE CWA WILL SEE TEMPERATURES DROP TO -5F TO -10F...WHILE THE SERN
PORTION OF THE CWA ONLY DROPS TO THE LOWER SINGLE DIGITS. THE
MODELS HAVE BEEN VERY CONSISTENT WITH THE PATTERN THROUGH THE WEEK
AND THE HIGH PRESSURE CENTER ASSOCIATED WITH THIS ARCTIC AIRMASS
WILL MOVE THROUGH SRN WISCONSIN AND NORTHERN ILLINOIS. SO...WHILE
AIR TEMPERATURES WILL BE SIMILAR TO THOSE SEEN ON TUESDAY
MORNING...WIND CHILLS WILL NOT BE QUITE AS LOW AS WINDS SHOULD NOT
BE QUITE AS STRONG. HOWEVER...THERE IS STILL SOME BUST POTENTIAL
FOR MIN TEMPS FRIDAY MORNING IF WINDS GO CALM RATHER THAN REMAINING
AROUND 5MPH. THE LIGHT WIND WOULD BE JUST ENOUGH TO TO KEEP THE SFC
STIRRED UP...LIMITING COOLING. ON THE OTHER HAND...IF THE SFC WINDS
CAN MANAGE TO GO CALM...AND SKIES CLEAR OUT ENOUGH...ENHANCED
RADIATIONAL COOLING AIDED BY SOME RESIDUAL SNOW COVER COULD ALLOW
TEMPERATURES TO DROP EVEN LOWER THAN CURRENTLY ANTICIPATED.
FOR THE WEEKEND AND INTO EARLY NEXT WEEK...WITH THE PATTERN
REMAINING QUICKLY PROGRESSIVE...TEMPERATURES FOR THE WEEKEND SHOULD
REBOUND BACK CLOSER TO SEASONAL NORMAL LEVELS. HIGHS SHOULD BE IN
THE UPPER 20S TO LOWER 30S. THE LONG RANGE MODEL GUIDANCE IS
INDICATING THE CHANCE FOR ANOTHER SHOT OF ARCTIC AIR WITH SUB-ZERO
TEMPERATES BY MONDAY MORNING. THE LONG RANGE FORECAST PERIOD SHOULD
BE DRY WITH THE NEXT CHANCE FOR ANY PCPN COMING EARLY NEXT WEEK AS
THE NEXT CLIPPER MOVES THROUGH THE AREA.
KREIN
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 03Z...
* MVFR CEILING TRENDS.
* A BRIEF PERIOD OF LIGHT SNOW THIS EVENING WITH 5-7SM VSBYS
BETWEEN ABOUT 03-05Z.
* CHANCE OF LIGHT SNOW OR FLURRIES MONDAY AFTN/EVENING.
RATZER
//DISCUSSION...UPDATED 00Z...
MAIN AVIATION FORECAST CONCERNS ARE MVFR CEILINGS THIS EVENING AND
CEILING TRENDS THROUGH MONDAY...IN ADDITION TO THE POTENTIAL FOR A
PERIOD OF LIGHT SNOW THIS EVENING AND ANOTHER MONDAY
AFTERNOON/EVENING.
LOW PRESSURE ASSOCIATED WITH THE OVERNIGHT/EARLY MORNING STORM
SYSTEM CONTINUES TO WEAKEN AS IT PULLS AWAY ACROSS THE EASTERN
GREAT LAKES REGION. A SERIES OF WEAKER DISTURBANCES WILL MAINTAIN
UPPER LEVEL TROUGHING ACROSS THE REGION THROUGH MONDAY NIGHT
HOWEVER...WITH AN EXTENSIVE AREA OF MVFR CLOUDS LINGERING ALONG
AND EAST OF THE MISSISSIPPI RIVER. ONE MID-LEVEL DISTURBANCE OVER
MN/IA PER SATELLITE IMAGERY WAS PRODUCING A NORTH-SOUTH BAND OF
LIGHT SNOW OVER PORTIONS OF WISCONSIN AND NORTHWEST IL EARLY THIS
EVENING...AND THOUGH RADAR TRENDS AND SFC VISIBILITY REPORTS
INDICATE DECREASING INTENSITY IT DOES APPEAR THAT A PERIOD OF
LIGHT SNOW WILL AFFECT KRFD FROM ROUGHLY 00-02Z...AND CHICAGO
AREA TERMINALS ROUGHLY 02-04Z THIS EVENING WITH PERHAPS A BRIEF
4-6SM VSBY REDUCTION. OTHERWISE...MAINLY JUST A FEW FLURRIES
EXPECTED OVERNIGHT...WITH MVFR CIGS GENERALLY 1100-1800 FT.
MODEL GUIDANCE AND NORTHWEST CLOUD-LEVEL WINDS WOULD SUPPORT A
CONTINUATION OF MVFR CIGS BLO 2000 FT...THOUGH SOME IMPROVEMENT TO
HIGH-MVFR OR EVEN VFR IS POSSIBLE EARLY MONDAY MORNING AS MID-
LEVELS DRY AND A BRIEF PERIOD OF SUBSIDENCE OCCURS BETWEEN
TONIGHTS DISTURBANCE AND ANOTHER WHICH WILL MOVE INTO THE AREA
MONDAY AFTERNOON. THIS NEXT STRONGER DISTURBANCE MAY BRING ANOTHER
PERIOD OF LIGHT SNOW TO THE TERMINALS MONDAY AFTERNOON/EVENING...
THOUGH DRY MID/UPPER LEVELS SUGGEST MAINLY LIGHT SNOW SHOWERS OR
FLURRIES.
WINDS...SURFACE LOW PRESSURE TROUGH WILL LINGER ACROSS WISCONSIN
IN RESPONSE TO UPPER LEVEL DISTURBANCES THROUGH THE PERIOD...WHILE
HIGH PRESSURE RIDGE BUILDS ACROSS THE LOWER MISSOURI AND OHIO
VALLEYS TO OUR SOUTHWEST. THIS WILL MAINTAIN WEST WINDS ACROSS THE
AREA THROUGH MONDAY...WITH A MODEST PRESSURE GRADIENT AND
STEEPENING LOW LEVEL LAPSE RATES WITH COLD AIR ADVECTION PRODUCING
SOME GUSTS INTO THE 15-20 KT RANGE MONDAY.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 03Z...
* HIGH CONFIDENCE IN MVFR CIGS THROUGH THIS EVENING. MEDIUM
CONFIDENCE IN CIG TRENDS LATE TONIGHT/MONDAY.
* HIGH CONFIDENCE IN LGT SNOW THIS EVENING...LOW CONFIDENCE IN
VSBY REDUCTIONS.
* MEDIUM CONFIDENCE IN LGT SNOW/FLURRIES MONDAY AFTN/EVE. LOW
CONFIDENCE IN CIG/VIS IMPACTS.
RATZER
//OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z...
TUESDAY...VFR DURING THE DAY. CHANCE OF LIGHT SNOW LATER TUESDAY
NIGHT WITH MVFR/IFR POSSIBLE.
WEDNESDAY...CHANCE OF LIGHT SNOW EARLY. MVFR/IFR POSSIBLE.
THURSDAY...VFR.
FRIDAY...VFR.
SATURDAY...VFR.
RATZER
&&
.MARINE...
244 PM...AS LOW PRESSURE MOVES ACROSS NEW ENGLAND TONIGHT AND
MONDAY...A WEAKER TROUGH WILL EXTEND WEST ACROSS THE LAKES REGION
INCLUDING CENTRAL LAKE MICHIGAN THROUGH MONDAY AFTERNOON. THIS
WILL ALLOW FOR NORTHERLY WINDS ACROSS THE NORTH HALF OF THE
LAKE...WITH INCREASING WESTERLY WINDS ACROSS THE SOUTHERN THIRD OR
QUARTER OF THE LAKE TONIGHT. THESE WESTERLY WINDS COULD INCREASE
INTO THE 20-25KT RANGE MONDAY AFTERNOON INTO MONDAY EVENING AND
TRENDS WILL NEED TO BE MONITORED WITH LATER FORECASTS. THIS TROUGH
WILL DISSIPATE MONDAY EVENING AS A RIDGE OF HIGH PRESSURE MOVES
ACROSS THE LAKE TUESDAY...WITH THE CENTER OF THE HIGH REMAINING
ACROSS THE OHIO VALLEY. ON THE BACK SIDE OF THIS RIDGE...WINDS
WILL TURN SOUTHERLY TUESDAY AFTERNOON AND QUICKLY INCREASE TO 30
KTS TUESDAY EVENING...AS A LARGE TROUGH OF LOW PRESSURE MOVES
ACROSS THE MIDWEST AND WESTERN LAKES. CONFIDENCE REGARDING LOW END
GALES IS LOW AT THIS DISTANCE BUT HAVE OPTED TO INCLUDE THEM
ACROSS THE NORTH HALF. WINDS TURN WESTERLY AND DIMINISH WEDNESDAY
AFTERNOON INTO WEDNESDAY EVENING...AS THE TROUGH PASSES ACROSS
THE LAKE. ANOTHER HIGH WILL MOVE FROM THE NORTHERN PLAINS THURSDAY
TO ACROSS THE SOUTHERN LAKES REGION FRIDAY. ANOTHER LOW WILL
QUICKLY MOVE ACROSS THE NORTHERN LAKES FRIDAY NIGHT. THE GRADIENT
WILL TIGHTEN AHEAD OF THIS SYSTEM WITH A SHORT PERIOD OF GALES
POSSIBLE. CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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[top]
Area Forecast Discussion
National Weather Service Lincoln IL
846 PM CST Sun Dec 22 2013
.DISCUSSION...
ISSUED 840 PM CST Sun Dec 22 2013
Storm system that brought the wintry weather to the region
yesterday continues to push well of to our east this evening.
Latest satellite and surface observations to our west indicate
a decrease in cloud cover over parts of east central Iowa which
was working its way east this evening. Latest RAP soundings not
very optimistic with respect to eroding the low level moisture
already in place so will continue to hold on to the cloud cover
overnight. Despite the cloud cover, low level cold advection
behind the storm system will drawn down some rather cold temps
by morning with overnight lows in the single digits in our
far northwest. Still seeing an occasional report of flurries
to our west over eastern Iowa and west central IL so will hold
on to the flurries for the overnight hours. Current zones are
in good shape, so other than the usual tweaks to the evening
hourly temperatures and winds, no significant enough changes
were made to warrant an evening update.
Smith
&&
.AVIATION...
ISSUED 540 PM CST Sun Dec 22 2013
Widespread MVFR and local IFR cigs will prevail over the area thru
the evening with a decrease in cloud cover from west to east expected
after midnight. Latest satellite data and surface obs indicate the
backedge of the clouds were still over parts of central Iowa, so it
will take another 6 to 8 hours before we see a marked improvement
in our area. Once we see the cloud band to shift off to our east
Monday morning, sct-bkn VFR cigs are expected thereafter. Surface
winds will remain out of the west to northwest at 10 to 15 kts
thru the period.
Smith
&&
.PREV DISCUSSION...
ISSUED 300 PM CST Sun Dec 22 2013
The short and medium range models are all in very good agreement
that central and eastern IL will experience quite a range of
temperatures during the next week as a series of northwest
flow/clipper systems take aim at the upper Midwest. This type of
flow also indicates that no major storms are on the horizon for
the next several days either.
SHORT TERM...Tonight through Tuesday
Low level cyclonic flow from the storm system moving through the
eastern Great Lakes will keep clouds and scattered snow flurries over
the forecast area through tonight and into much of the day Monday.
There may be a few breaks in areas south of a Jacksonville-SPI-
DEC-Paris line Monday as surface ridging tries to nose into the
area, but overall clouds will prevail. The clouds will not do much
to keep us warmer since plenty of low level cold air upstream is
poised to move into the area. Lows tonight will be in the single
digits west of the Illinois River, with teens in central IL and
and 20s in the southeast. Continued cold advection Monday will
result in nearly steady temperatures or only very minor rises.
Arctic high pressure with a central pressure around 1040 mb will
drop into the mid MS Valley by daybreak Tuesday. This will give us
very cold temperatures, with sub-zero readings west of I-55 and
single digits in the rest of the forecast area. The gradient ahead
of the high pressure area will be moderately strong, with surface
winds 10-15 mph in the evening and around 10 mph overnight. The
resulting wind chill values will be below zero north of I-70 with
-10 to -17 north of I-72 later Monday evening into Tuesday morning.
May need a wind chill advisory in later forecasts if this trend
continues.
The cold temperatures will continue on Christmas Eve as the high
slowly moves across Illinois. However, a southerly flow is
expected to develop Tuesday night, once again resulting in very
little diurnal temperature swing. The next in a series of clipper
systems will track into the upper Midwest later on Christmas Eve.
The best lift with this system will be in WI and northern IL, but
there is a chance for a little light snow by Christmas morning -
mainly along the I-74 corridor.
LONG TERM...Christmas Day through Sunday
The cold front associated with the Christmas morning clipper will
be approaching from the northwest by evening. Again, the best
upper support will be to the north, so will keep the chances for
snow along and north of I-74. The rest of the area will be mostly
cloudy on Christmas Day with a few snow flurries at times. The
southerly winds ahead of the front will allow temperatures to
rebound into the 30s. However, this will be short lived after the
front moves through Wednesday night. Highs Thursday will mainly be
in the 20s, with lower to middle 30s in southeast IL. The coldest
air with the next Arctic high will push in Friday morning,
although at this time it does not appear that it will be as cold
as the previous Arctic airmass.
The upper level flow will back to more of a westerly/zonal flow by
the weekend as an upper trough from the Canadian Rockies digs
toward the southern Plains. The result for Illinois will be
warmer, more seasonal temperatures for Saturday and Sunday. The
GFS and European models are similar in indicating a cold front
approaching Sunday. However, with high pressure expected to be
parked over the southern states, moisture will be quite limited.
Will hold off on chance PoPs for now, and go with a dry forecast
since the higher probability appears to be toward the Great Lakes
area.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
307 AM CST SAT DEC 21 2013
.DISCUSSION...
744 PM CST
THE FREEZING RAIN ADVISORY FOR NORTH CENTRAL AND EXTREME
NORTHEAST ILLINOIS WAS ALLOWED TO EXPIRE. FREEZING RAIN HAD
DIMINISHED TO FREEZING DRIZZLE EARLY THIS EVENING AND HAS NOW
ENDED ACROSS MOST OF THE ADVISORY AREA. THERE MAY BE A LINGERING
PATCH OR TWO OF FREEZING DRIZZLE BUT THOSE TOO ARE EXPECTED TO
END VERY SHORTLY. RADARS AT MKX...DVN AND ARX HAVE ALL SHOWN A W
TO E CLEARING OF THE WEAK ECHOES WHILE AN AREA OF WEAK ECHOES
ASSOCIATED WITH SOME DRIZZLE AND LIGHT RAIN HAD BLOSSOMED
OVERHEAD BUT IS STEADILY MOVING TO THE E SO THIS PRECIP IS
EXPECTED TO END 9PM CST AS THE TAIL END OF THE LATEST MINOR SHORT
WAVE TROUGH MOVES E OF THE AREA. FORTUNATELY WHERE THIS PRECIP IS
OCCURRING SURFACE TEMPERATURES ARE ABOVE FREEZING.
THE LAKE AND PORTER INDIANA COUNTIES PORTION OF THE DENSE FOG
ADVISORY ALSO WAS ALLOWED TO EXPIRE AS THE FRONTAL BOUNDARY HAD
DRIFTED SLIGHTLY SOUTHWARD ALLOWING WINDS TO BECOME LIGHT
NORTHWEST AND VISIBILITIES TO IMPROVER ABOVE DENSE FOG CRITERIA.
THE REMAINDER OF THE DENSE FOG ADVISORY HAS BEEN EXTENDED UNTIL
9 PM CST. THE WEAK SURFACE REFLECTION OF THE SHORT WAVE WAS IN THE
VPZ-SBN AREA. AS IT CONTINUES SLOWLY TO THE E THE REST OF THE
EVENING THE FRONTAL BOUNDARY WILL CONTINUE TO SAG DEEPER INTO THE
AREA THAT REMAINS UNDER THE ADVISORY WITH AN THINNING OF THE DENSE
FOG EXPECTED TO OCCUR.
TRS
//PREV DISCUSSION...
337 PM CST...INCLUDING UPDATED WINTER STORM DISCUSSION BELOW...
TONIGHT THROUGH SATURDAY MORNING...
325 PM CST...
TONIGHT...THE FREEZING RAIN ADVISORY CONTINUES THROUGH 7 PM FOR
FAR NORTHERN IL AS LIGHT SHOWER ACTIVITY AND PATCHY DRIZZLE
CONTINUE TO OVERRIDE A SUBFREEZING BOUNDARY LAYER. THE GOES WATER
VAPOR LOOP SHOWS MODEST DRYING OVER THE AREA IN THE MID-
LEVELS...BUT JUST ENOUGH WEAK ASCENT APPEARS TO BE PRESENT WITHIN
THE LOW-LEVEL SATURATION TO KEEP TRIGGERING THESE LIGHT SHOWERS.
THE FREEZING DEMARCATION HELD STEADY MUCH OF TODAY FROM NEAR
MENDOTA NORTHEAST TO LAKE COUNTY IL. DO NOT SEE MUCH SHIFT WITH
THAT THROUGH EARLY THIS EVE. SO WITH IT BEING A BUSY HOLIDAY
TRAVEL TIME ADDED TO THE NORMAL FRIDAY COMMUTE...CERTAINLY LET THE
ADVISORY CONTINUE TO 7 PM. AS TEMPERATURES SLOWLY FALL BELOW
FREEZING SOUTH OF THE ADVISORY...UNTREATED WET ROADWAYS ARE LIKELY
TO EXPERIENCE SOME GLAZING TOO.
THE DENSE FOG ADVISORY FOR SOUTHERN AREAS SHOULD BE FINE ENDING AT 7
PM AS WINDS BEGIN TO INCREASE BEHIND THE BOUNDARY AND LOWER DEW
POINTS SEEP IN.
FORCING REMAINS WEAK THROUGH MUCH OF TONIGHT WITH LIMITED MOISTURE
TRANSPORT AND REALLY ANY TYPE OF MID-LEVEL WAVE/TRIGGER. SO WHILE
THERE IS A CHANCE FOR FREEZING DRIZZLE...ANY PRECIP SHOULD BE PATCHY
AT BEST AND LIGHT AFTER 7-8 PM.
SATURDAY MORNING...THE RAP AND OTHER HIGH RES GUIDANCE KEY IN ON
MOISTURE TRANSPORT AHEAD OF THE MAIN DEVELOPING SYSTEM /DESCRIBED
BELOW/ ADVANCING INTO THE SOUTHERN CWA IN THE PRE-DAWN HOURS AND
INTO SAT MORNING. THE CONVERGENCE AT THE NOSE OF THIS CREEPS INTO
THE SOUTHERN FORECAST AREA IN THE MORNING...WHERE FREEZING DRIZZLE
AND RAIN LOOK POSSIBLE...THOUGH THERE COULD BE QUITE A BIT OF RAIN
AND CONVECTIVE ACTIVITY ACROSS THE MID-MISSISSIPPI VALLEY THAT MAY
HALT THE FRONT EDGE ADVANCE OF THE PRECIP. HAVE CONTINUED MENTION
OF LIGHT FREEZING PRECIP SAT MORNING ACROSS AREAS MAINLY SOUTH OF
I-80.
MTF
DISCUSSION ON WINTER STORM.
WE HAVE UPGRADED PORTIONS OF THE WINTER STORM WATCH TO WARNING AND
CONTINUED THE WATCH FOR LAKE AND KANE COUNTIES.
THE VIGOROUS MID LEVEL FEATURE...CURRENTLY NOTED IN WATER VAPOR NEAR
THE BAJA OF CALIFORNIA EARLY THIS AFTERNOON IS FORECAST TO TAKE ON A
NEGATIVE TILT AS IT MOVES OUT ACROSS THE TEXAS PANHANDLE AROUND
MIDDAY ON SATURDAY. THIS FEATURE WILL LIFT QUICKLY
NORTH-NORTHEASTWARD ACROSS THE MID MISSISSIPPI VALLEY AND ACROSS
NORTHERN ILLINOIS SATURDAY NIGHT. MODEL GUIDANCE CONTINUES TO WAVER
AROUND A BIT ON THE ACTUAL TRACK OF THE 850 AND SURFACE LOWS.
THEREFORE...I HAVE TRENDED CLOSER TO THE ENSEMBLE MEANS...WHICH
TRACK THE 850 LOW RIGHT ACROSS NORTHEASTERN ILLINOIS LATE SATURDAY
NIGHT. THIS TRACK FAVORS NORTH CENTRAL AND FAR NORTHEASTERN ILLINOIS
FOR THE HEAVIEST SNOWFALL...ESPECIALLY SATURDAY NIGHT INTO EARLY
SUNDAY AS STRONG FRONTOGENESIS SETS UP WITHIN THE DEFORMATION
ZONE...JUST TO THE NORTH AND WEST OF THE 850 LOW TRACK. THIS WILL
LIKELY SUPPORT AN AREA OF HEAVY SNOWFALL ACROSS THESE AREAS...WITH
SNOW RATES LIKELY TO REACH OR EVEN EXCEED AN 1 INCH PER HOUR AT
TIMES...GIVEN THE GOOD COUPLING OF THE LARGE SCALE FORCING FOR
ASCENT FROM THE MID LEVEL WAVE AND THE GOOD FRONTOGENESIS. MID LEVEL
LAPSE RATES WILL ALSO SUPPORT GOOD SNOWFALL ACROSS THE WARNING
AREAS. I CHOSE TO LEAVE THE WATCH IN PLACE FOR LAKE AND KANE
COUNTIES. THESE AREAS MAY ALSO SEE 6+ INCHES OF SNOW...IN PORTIONS
OF THE COUNTIES...BUT DUE TO THE POTENTLY FOR SOME SLIGHT SHIFTS YET
IN THE TRACK OF THE SYSTEM...WITH A POTENTIAL FOR A FARTHER
NORTHWEST TRACK...I CHOOSE TO HOLD OFF.
THE OTHER CONCERN IS THE THREAT FOR FREEZING RAIN AND SLEET
ACCUMULATIONS...ESPECIALLY ACROSS SOUTHERN SECTIONS OF THE WARNING
AREA...AND PLACES TO THE SOUTH. TEMPERATURES ARE EXPECTED TO REMAIN
RIGHT AROUND THE FREEZING POINT...SO IT APPEARS THAT ICING AMOUNTS
MAY BE LIMITED SOME...ESPECIALLY NEAR CHICAGO. WITH THAT BEING
SAID...I STILL THINK THERE IS A DECENT POTENTIAL TO HAVE AN AREA OF
SOME ICE ACCUMULATIONS...OF 0.1 TO 0.2 INCHES...PRIMARILY NORTH OF
I-80 UP TO AROUND THE I-88 CORRIDOR. CLOSER TO THE LAKE AND THE
CITY ICE AMOUNTS MAY BE LESS DUE TO THE FLOW OFF THE LAKE POSSIBLY
RESULTING IN TEMPS JUST ABOVE FREEZING. IT APPEARS THE MAIN ICING
THREAT WILL NOT OCCUR UNTIL TOMORROW AFTERNOON AND INTO THE
EVENING. THEREFORE...WE HAVE SOME TIME TO BETTER IRON OUT THE
AREAS MOST SUSCEPTIBLE TO ICING. WE WILL HIGHLIGHT THIS THREAT IN
AN SPS.
IT ALSO APPEARS THE HEAVY RAIN THREAT WILL MAINLY BE ACROSS MY
SOUTHEASTERN COUNTIES...SO NO CHANGES TO THE GOING FLOOD WATCH.
STRONG MOISTURE CONVERGENCE AND ANOMALOUSLY HIGH PWATS WILL LIKELY
PRODUCE AMOUNTS IN EXCESS OF AN INCH OR SO ACROSS THESE AREAS...AND
WITH ALL OF THIS BECOMING RUNOFF...RAPID RISES ON AREA STREAMS ARE
EXPECTED.
THE SNOW THREAT FOR AREAS SOUTH OF THE CURRENT WARNING AREA APPEAR
TO SOMEWHAT LIMITED...WITH A SHARP GRADIENT IN THE SNOW
ACCUMULATIONS EXPECTED. AN IMPRESSIVE DRY SLOT WILL PUNCH IN ACROSS
THE AREA LATE SATURDAY NIGHT INTO SUNDAY...LIKELY RESULT IN ONLY
LIGHT SNOW OR EVEN FZ DRIZZLE GIVEN THE LOSE OF ICE IN THE CLOUDS.
TOTAL SNOW AMOUNTS LOOK TO DROP TO UNDER AN INCH BY THE TIME YOU GET
CLOSE TO CHICAGO AND INTERSTATE 80.
MUCH COLDER AIR SPILLS IN ACROSS THE AREA SUNDAY NIGHT...WITH LIGHT
PRECIP CONTINUING IN ASSOCIATION WILL ANOTHER UPPER LEVEL
DISTURBANCE. TEMPERATURES WILL LIKELY DROP INTO THE SINGLE DIGITS
IN MOST AREAS SUNDAY NIGHT. THUS...ANY STANDING WATER
REMAINING...WITH LIKELY QUICKLY FREEZE IN PLACE ACROSS THE AREA.
KJB
EXTENDED FORECAST PERIOD /MONDAY MORNING THROUGH FRIDAY INCLUDING
THE CHRISTMAS HOLIDAY...
300 PM CST...
THE SENSIBLE WEATHER WILL QUIET CONSIDERABLY WITH THE MAIN FORECAST
CONCERNS FOCUSING ON TEMPERATURES AND THE CHANCE FOR SOME LIGHT
SNOW ON CHRISTMAS EVE AND EARLY CHRISTMAS DAY. THE GENERAL TREND
FOR THE EXTENDED FORECAST PERIOD WILL BE FOR MUCH BELOW NORMAL
TEMPERATURES WITH THE ONLY CHANCE FOR SOME LIGHT SNOW ON CHRISTMAS
EVE INTO CHRISTMAS DAY.
A HIGH AMPLITUDE LONGWAVE TROUGH IS EXPECTED TO CARVE OUT OVER THE
CNTRL CONUS WITH THE TROUGH AXIS EXTENDING FROM HUDSON BAY THROUGH
CENTRAL TEXAS. INITIALLY ON MONDAY...THE LOCAL AREA WILL SEE THE
TROUGH AXIS MOVING THROUGH THE AREA TRANSITIONING THE REGION FROM
RELATIVE WARM ADVECTION TO STRONG COLD ADVECTION. TEMPERATURES WILL
DROP OFF QUICKLY BY MONDAY MORNING...WITH LOWS EXPECTED TO DROP ONTO
THE SINGLE DIGITS WEST OF THE FOX VALLEY AND I-55 CORRIDOR. LOWS
OVER THE EASTERN PORTION OF THE FORECAST AREA SHOULD HANG IN THE
MIDDLE TO UPPER TEENS. AS THE LONGWAVE TROUGH CONTINUES TO THE ERN
CONUS MONDAY AND MONDAY NIGHT...WEAK UPPER RIDGING WILL BUILD ACROSS
THE UPPER MISSISSIPPI VALLEY...WITH THE AMPLITUDE OF THE UPPER LEVEL
PATTERN CONTINUING TO AMPLIFY. WITH DEEP LAYER FLOW REMAINING ON
THE NWLY FLOW SIDE OF THE UPPER RIDGE...TEMPERATURES WILL CONTINUE
TO DROP WITH LOWS TUESDAY MORNING BELOW ZERO OVER MUCH OF THE CWA...
GENERALLY WEST OF A LINE FROM WAUKEGAN TO PONTIAC...WITH THE
COLDEST AIR OVER THE ROCKFORD AREA WHERE TEMPS SHOULD BOTTOM OUT AT
-5F TO -10F. WIND CHILLS WILL BE A CONCERN AS WELL. WITH WINDS OF
5-10 KT LIKELY...WIND CHILLS WILL APPROACH THE -20F WIND CHILL
ADVISORY CRITERIA WEST OF THE FOX VALLEY AND I-55 CORRIDOR. BY
TUESDAY NIGHT...THE LONGER RANGE MODELS ARE ADVERTISING A PAIR OF
NORTHERN STREAM SHORTWAVES TRACKING ACROSS THE NRN PLAINS. THE
NRN-MOST WAVE...WHICH IS ALSO THE STRONGER OF THE PAIR...SHOULD
TRACK TO THE EAST...ACROSS THE UPPER GREAT LAKES WHILE THE MORE
SOUTHERLY...WEAKER WAVE DROPS THROUGH THE NRN PLAINS TO THE MIDDLE
MISSISSIPPI VALLEY. THIS THERE IS SOME DISCREPANCY AMONG THE LONGER
RANGE GUIDANCE ON THE SPEED OF PROGRESSION OF THIS WAVE...BUT THE
GENERAL CONSENSUS IS THAT THE WAVE WILL CROSS THE MIDDLE MISSISSIPPI
VALLEY...TRACKING OVER THE IL/WI BOARDER. FOLLOWING A PERIOD OF
STRONG COLD/DRY ADVECTION...THERE WILL BE LITTLE IN SITU MOISTURE
FOR THE SYSTEM TO WORK WITH AND WILL LARGELY HAVE TO RELY ON
DYNAMICS TO PRODUCE ANY PCPN. AT THIS POINT...ANTICIPATE THAT UPPER
DYNAMICS SHOULD BE STRONG ENOUGH TO PRODUCE AT LEAST SOME LIGHT SNOW
FOR LATE CHRISTMAS EVE INTO EARLY CHRISTMAS DAY. GIVEN THE LACK OF
DEEP LAYER MOISTURE OR ANY SIGNIFICANT LOW LEVEL MOISTURE TRANSPORT
AS FLOW THROUGH THE LOWER LEVELS SHOULD BE MORE WESTERLY AND UNABLE
TO TAP ANY GULF MOISTURE...ANY ACCUMULATIONS WILL LIKELY BE LIGHT.
A BRIEF PERIOD OF MORE WLY OR AT LEAST BROAD...FLAT TROUGHING SHOULD
COVER THE MIDWEST ON WEDNESDAY...ALLOWING FOR SOME MODERATION OF
TEMPERATURES ON WEDNESDAY AND THURSDAY...WITH HIGHS IN THE UPPER 20S
TO LOWER 30S ON WEDNESDAY AND UPPER TEENS TO MIDDLE 20S ON THURSDAY.
A REINFORCING SHOT OF COLD AIR ASSOCIATED WITH A STRONG NORTHERN
STREAM SHORTWAVE DIGGING INTO THE UPPER MISSISSIPPI VALLEY AND
SOUTHERN GREAT LAKES WILL BRING SUB-ZERO TEMPERATURES BACK TO MUCH
OF THE CWA FOR FRIDAY MORNING.
KREIN
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 09Z...
* LIFR CIGS EXPECTED TO LIFT TO IFR THIS MORNING...WITH SOME
CHANCE FOR MVFR DURING THE DAY.
* IFR VSBY GRADUALLY IMPROVES TO MVFR THROUGH THE MORNING.
* TIMING AND TYPE OF PRECIP ONSET TODAY.
* VARIABLE WEST TO NORTHWEST WINDS TURNING NORTHEAST AND
INCREASING IN SPEED THROUGH THE MORNING.
MDB
//DISCUSSION...UPDATED 09Z...
VSBY HAS BEGUN TO LEVEL OFF AND EVEN SLIGHTLY IMPROVE WITH VALUES
MAINLY IN THE 1-2SM RANGE. EXPECT THAT THERE WILL BE A GRADUAL
IMPROVEMENT THIS MORNING WITH SOME SLIGHT LOW LEVEL DRYING TAKING
PLACE. HOWEVER...IMPROVEMENT WILL PROBABLY BE STUNTED BY
APPROACHING PRECIP INTO THE AFTERNOON. CIGS SHOULD ALSO GRADUALLY
IMPROVE BUT CONFIDENCE IN HOW MUCH REMAINS LOW.
MDB
FROM 06Z...
ONE LOW PRESSURE AREA IS OFF TO THE EAST WHILE THE NEXT LOW
DEVELOPS OVER SOUTHWEST ARKANSAS. DRIZZLE/FREEZING DRIZZLE HAS
DIMINISHED IN COVERAGE DURING THE EVENING BUT VSBY HAS STRUGGLED
TO IMPROVE IN MANY AREAS...THOUGH ORD HAS IMPROVED TO GREATER THAN
6SM. SEVERAL SITES HAVE LOST SOME VSBY IN THE LAST HOUR OR SO
INCLUDING MDW SO WILL CARRY SOME LOWER VSBY THAN PREVIOUS TAFS TO
ACCOUNT FOR THIS. TOUGH TO SAY WHETHER THERE WILL BE MUCH
IMPROVEMENT OVERNIGHT DESPITE THE LACK OF DRIZZLE NOW OCCURRING SO
FURTHER ADJUSTMENTS MAY BE NEEDED. OTHERWISE EXPECT IFR/LIFR CIGS
TO PERSIST THROUGH THE MORNING.
THE ARKANSAS LOW WILL MOVE NORTHEAST TODAY SPREADING PRECIPITATION
NORTHWARD INTO THE AREA. -DZ/-FZDZ MAY DEVELOP AS UPWARD MOTION
BEGINS TO INCREASE MID/LATE MORNING. OTHERWISE CHANCES FOR MIXED
PRECIPITATION WILL INCREASE DURING THE AFTERNOON FROM SOUTH TO
NORTH...WITH RAIN/SNOW/SLEET ALL POSSIBLE. WITH SURFACE TEMPS
RIGHT AROUND FREEZING...SOME FREEZING RAIN MAY ALSO OCCUR. PRECIP
INTENSITY MAXIMIZES BY EARLY EVENING WITH WARMER AIR MOVING IN
ALOFT FAVORING MORE RAIN AT MDW/GYY WITH RAIN/SLEET POSSIBLE AT
ORD/DPA AND A TRANSITION FROM SNOW/SLEET TO SNOW AT RFD WHERE
TEMPS ALOFT WILL BE COLDER. DRIER AIR IS FORECAST TO MOVE IN ALOFT
DURING THE LATE EVENING HOURS WHICH WOULD LIKELY RESULT IN A LULL
IN PRECIP INTENSITY AND FAVOR -DZ/-FZDZ DEPENDING ON SURFACE
TEMPERATURE. RFD MAY REMAIN ON THE FRINGE OF THE DRY SLOT ALLOWING
FOR FLUCTUATIONS BETWEEN SNOW AND -FZDZ. WEST AND NORTHWEST WINDS
WILL TURN NORTHEAST LATER THIS MORNING AND INCREASE IN SPEED INTO
THE EVENING.
MDB
//ORD AND MDW CONFIDENCE...UPDATED 09Z...
* MEDIUM CONFIDENCE IN LIFR CIGS LIFTING TO IFR...LOW CONFIDENCE
IN POTENTIAL FOR MVFR CIGS TODAY.
* MEDIUM-HIGH CONFIDENCE IN IFR VSBY IMPROVING TO MVFR THIS
MORNING.
* MEDIUM CONFIDENCE IN PRECIP TIMING/TYPE FORECAST.
* HIGH CONFIDENCE IN WIND TRENDS.
MDB
//OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z...
SUNDAY...SNOW ESPECIALLY IN THE MORNING. IFR LIKELY. BRIEF LIFR
POSSIBLE EARLY.
MONDAY...CHANCE OF SNOW SHOWERS. MVFR/IFR POSSIBLE.
TUESDAY...VFR.
WEDNESDAY...CHANCE OF LIGHT SNOW. MVFR/IFR POSSIBLE.
THURSDAY...SLIGHT CHANCE OF LIGHT SNOW. MVFR POSSIBLE.
RATZER
&&
.MARINE...
300 AM CST
ONE AREA OF LOW PRESSURE HAS DEPARTED TO THE EAST AND IS NOW
CROSSING LAKE ERIE. ANOTHER LOW IS DEVELOPING ACROSS WESTERN
ARKANSAS AND WILL LIFT NORTHEAST TODAY. THE LOW WILL THEN REACH
NORTHERN INDIANA SUNDAY MORNING BEFORE BEGINNING TO WEAKEN AS IT
CROSSES NEW ENGLAND SUNDAY EVENING. HIGH PRESSURE WILL MOVE
SOUTHWARD ACROSS MANITOBA AND WESTERN ONTARIO TODAY AND WORK WITH
THE DEVELOPING LOW TO STRENGTHEN THE PRESSURE GRADIENT ACROSS LAKE
MICHIGAN TONIGHT AND SUNDAY MORNING. WINDS WILL TURN NORTHEASTERLY
TODAY ACROSS THE LAKE. SPEEDS LOOK TO TOP OUT AROUND 30 KT...BUT
CANNOT RULE OUT SOME GALE FORCE GUSTS LATE TONIGHT. WILL GO AHEAD
AND HOIST A SMALL CRAFT ADVISORY FOR THE ILLINOIS NEARSHORE WATERS
FROM THIS EVENING THROUGH SUNDAY AFTERNOON...AND FOR THE INDIANA
NEARSHORE WATERS UNTIL EARLY MONDAY MORNING AS WINDS
TURN FROM NORTHEAST TO NORTH AND THEN NORTHWEST. STRONG HIGH
PRESSURE WILL THEN SPREAD SOUTHWARD INTO THE MIDWEST AND WESTERN
GREAT LAKES MONDAY INTO TUESDAY WITH THE ASSOCIATED RIDGE AXIS
CROSSING LAKE MICHIGAN TUESDAY. DIMINISHING WINDS WILL RESULT...BUT
SPEEDS WILL INCREASE AS THE DIRECTION TURNS SOUTHERLY TUESDAY NIGHT.
LOW PRESSURE IS EXPECTED TO MOVE ACROSS THE CANADIAN PRAIRIES INTO
WESTERN ONTARIO WEDNESDAY WITH THE STRENGTH OF THE LOW DICTATING THE
POTENTIAL FOR GALES WEDNESDAY. THE LOW WILL PASS LATER WEDNESDAY
TURNING WINDS WESTERLY.
MDB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WINTER STORM WARNING...ILZ003-ILZ004-ILZ005-ILZ008-ILZ010-
ILZ011...4 PM SATURDAY TO 10 AM SUNDAY.
FREEZING RAIN ADVISORY...ILZ023-ILZ032-ILZ033-ILZ039 UNTIL 1 PM
SATURDAY.
FLOOD WATCH...ILZ033-ILZ039...NOON SATURDAY TO 10 PM SATURDAY.
WINTER WEATHER ADVISORY...ILZ006-ILZ012...4 PM SATURDAY TO 10 AM
SUNDAY.
WINTER WEATHER ADVISORY...ILZ019-ILZ020-ILZ021-ILZ022...NOON
SATURDAY TO 10 PM SATURDAY.
WINTER WEATHER ADVISORY...ILZ013-ILZ014...2 PM SATURDAY TO 10 PM
SATURDAY.
IN...FREEZING RAIN ADVISORY...INZ001-INZ002-INZ010-INZ011 UNTIL 1 PM
SATURDAY.
FLOOD WATCH...INZ010-INZ011-INZ019...NOON SATURDAY TO 10 PM
SATURDAY.
LM...NONE.
&&
$$
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1210 AM CST SAT DEC 21 2013
.DISCUSSION...
744 PM CST
THE FREEZING RAIN ADVISORY FOR NORTH CENTRAL AND EXTREME
NORTHEAST ILLINOIS WAS ALLOWED TO EXPIRE. FREEZING RAIN HAD
DIMINISHED TO FREEZING DRIZZLE EARLY THIS EVENING AND HAS NOW
ENDED ACROSS MOST OF THE ADVISORY AREA. THERE MAY BE A LINGERING
PATCH OR TWO OF FREEZING DRIZZLE BUT THOSE TOO ARE EXPECTED TO
END VERY SHORTLY. RADARS AT MKX...DVN AND ARX HAVE ALL SHOWN A W
TO E CLEARING OF THE WEAK ECHOES WHILE AN AREA OF WEAK ECHOES
ASSOCIATED WITH SOME DRIZZLE AND LIGHT RAIN HAD BLOSSOMED
OVERHEAD BUT IS STEADILY MOVING TO THE E SO THIS PRECIP IS
EXPECTED TO END 9PM CST AS THE TAIL END OF THE LATEST MINOR SHORT
WAVE TROUGH MOVES E OF THE AREA. FORTUNATELY WHERE THIS PRECIP IS
OCCURRING SURFACE TEMPERATURES ARE ABOVE FREEZING.
THE LAKE AND PORTER INDIANA COUNTIES PORTION OF THE DENSE FOG
ADVISORY ALSO WAS ALLOWED TO EXPIRE AS THE FRONTAL BOUNDARY HAD
DRIFTED SLIGHTLY SOUTHWARD ALLOWING WINDS TO BECOME LIGHT
NORTHWEST AND VISIBILITIES TO IMPROVER ABOVE DENSE FOG CRITERIA.
THE REMAINDER OF THE DENSE FOG ADVISORY HAS BEEN EXTENDED UNTIL
9 PM CST. THE WEAK SURFACE REFLECTION OF THE SHORT WAVE WAS IN THE
VPZ-SBN AREA. AS IT CONTINUES SLOWLY TO THE E THE REST OF THE
EVENING THE FRONTAL BOUNDARY WILL CONTINUE TO SAG DEEPER INTO THE
AREA THAT REMAINS UNDER THE ADVISORY WITH AN THINNING OF THE DENSE
FOG EXPECTED TO OCCUR.
TRS
//PREV DISCUSSION...
337 PM CST...INCLUDING UPDATED WINTER STORM DISCUSSION BELOW...
TONIGHT THROUGH SATURDAY MORNING...
325 PM CST...
TONIGHT...THE FREEZING RAIN ADVISORY CONTINUES THROUGH 7 PM FOR
FAR NORTHERN IL AS LIGHT SHOWER ACTIVITY AND PATCHY DRIZZLE
CONTINUE TO OVERRIDE A SUBFREEZING BOUNDARY LAYER. THE GOES WATER
VAPOR LOOP SHOWS MODEST DRYING OVER THE AREA IN THE MID-
LEVELS...BUT JUST ENOUGH WEAK ASCENT APPEARS TO BE PRESENT WITHIN
THE LOW-LEVEL SATURATION TO KEEP TRIGGERING THESE LIGHT SHOWERS.
THE FREEZING DEMARCATION HELD STEADY MUCH OF TODAY FROM NEAR
MENDOTA NORTHEAST TO LAKE COUNTY IL. DO NOT SEE MUCH SHIFT WITH
THAT THROUGH EARLY THIS EVE. SO WITH IT BEING A BUSY HOLIDAY
TRAVEL TIME ADDED TO THE NORMAL FRIDAY COMMUTE...CERTAINLY LET THE
ADVISORY CONTINUE TO 7 PM. AS TEMPERATURES SLOWLY FALL BELOW
FREEZING SOUTH OF THE ADVISORY...UNTREATED WET ROADWAYS ARE LIKELY
TO EXPERIENCE SOME GLAZING TOO.
THE DENSE FOG ADVISORY FOR SOUTHERN AREAS SHOULD BE FINE ENDING AT 7
PM AS WINDS BEGIN TO INCREASE BEHIND THE BOUNDARY AND LOWER DEW
POINTS SEEP IN.
FORCING REMAINS WEAK THROUGH MUCH OF TONIGHT WITH LIMITED MOISTURE
TRANSPORT AND REALLY ANY TYPE OF MID-LEVEL WAVE/TRIGGER. SO WHILE
THERE IS A CHANCE FOR FREEZING DRIZZLE...ANY PRECIP SHOULD BE PATCHY
AT BEST AND LIGHT AFTER 7-8 PM.
SATURDAY MORNING...THE RAP AND OTHER HIGH RES GUIDANCE KEY IN ON
MOISTURE TRANSPORT AHEAD OF THE MAIN DEVELOPING SYSTEM /DESCRIBED
BELOW/ ADVANCING INTO THE SOUTHERN CWA IN THE PRE-DAWN HOURS AND
INTO SAT MORNING. THE CONVERGENCE AT THE NOSE OF THIS CREEPS INTO
THE SOUTHERN FORECAST AREA IN THE MORNING...WHERE FREEZING DRIZZLE
AND RAIN LOOK POSSIBLE...THOUGH THERE COULD BE QUITE A BIT OF RAIN
AND CONVECTIVE ACTIVITY ACROSS THE MID-MISSISSIPPI VALLEY THAT MAY
HALT THE FRONT EDGE ADVANCE OF THE PRECIP. HAVE CONTINUED MENTION
OF LIGHT FREEZING PRECIP SAT MORNING ACROSS AREAS MAINLY SOUTH OF
I-80.
MTF
DISCUSSION ON WINTER STORM.
WE HAVE UPGRADED PORTIONS OF THE WINTER STORM WATCH TO WARNING AND
CONTINUED THE WATCH FOR LAKE AND KANE COUNTIES.
THE VIGOROUS MID LEVEL FEATURE...CURRENTLY NOTED IN WATER VAPOR NEAR
THE BAJA OF CALIFORNIA EARLY THIS AFTERNOON IS FORECAST TO TAKE ON A
NEGATIVE TILT AS IT MOVES OUT ACROSS THE TEXAS PANHANDLE AROUND
MIDDAY ON SATURDAY. THIS FEATURE WILL LIFT QUICKLY
NORTH-NORTHEASTWARD ACROSS THE MID MISSISSIPPI VALLEY AND ACROSS
NORTHERN ILLINOIS SATURDAY NIGHT. MODEL GUIDANCE CONTINUES TO WAVER
AROUND A BIT ON THE ACTUAL TRACK OF THE 850 AND SURFACE LOWS.
THEREFORE...I HAVE TRENDED CLOSER TO THE ENSEMBLE MEANS...WHICH
TRACK THE 850 LOW RIGHT ACROSS NORTHEASTERN ILLINOIS LATE SATURDAY
NIGHT. THIS TRACK FAVORS NORTH CENTRAL AND FAR NORTHEASTERN ILLINOIS
FOR THE HEAVIEST SNOWFALL...ESPECIALLY SATURDAY NIGHT INTO EARLY
SUNDAY AS STRONG FRONTOGENESIS SETS UP WITHIN THE DEFORMATION
ZONE...JUST TO THE NORTH AND WEST OF THE 850 LOW TRACK. THIS WILL
LIKELY SUPPORT AN AREA OF HEAVY SNOWFALL ACROSS THESE AREAS...WITH
SNOW RATES LIKELY TO REACH OR EVEN EXCEED AN 1 INCH PER HOUR AT
TIMES...GIVEN THE GOOD COUPLING OF THE LARGE SCALE FORCING FOR
ASCENT FROM THE MID LEVEL WAVE AND THE GOOD FRONTOGENESIS. MID LEVEL
LAPSE RATES WILL ALSO SUPPORT GOOD SNOWFALL ACROSS THE WARNING
AREAS. I CHOSE TO LEAVE THE WATCH IN PLACE FOR LAKE AND KANE
COUNTIES. THESE AREAS MAY ALSO SEE 6+ INCHES OF SNOW...IN PORTIONS
OF THE COUNTIES...BUT DUE TO THE POTENTLY FOR SOME SLIGHT SHIFTS YET
IN THE TRACK OF THE SYSTEM...WITH A POTENTIAL FOR A FARTHER
NORTHWEST TRACK...I CHOOSE TO HOLD OFF.
THE OTHER CONCERN IS THE THREAT FOR FREEZING RAIN AND SLEET
ACCUMULATIONS...ESPECIALLY ACROSS SOUTHERN SECTIONS OF THE WARNING
AREA...AND PLACES TO THE SOUTH. TEMPERATURES ARE EXPECTED TO REMAIN
RIGHT AROUND THE FREEZING POINT...SO IT APPEARS THAT ICING AMOUNTS
MAY BE LIMITED SOME...ESPECIALLY NEAR CHICAGO. WITH THAT BEING
SAID...I STILL THINK THERE IS A DECENT POTENTIAL TO HAVE AN AREA OF
SOME ICE ACCUMULATIONS...OF 0.1 TO 0.2 INCHES...PRIMARILY NORTH OF
I-80 UP TO AROUND THE I-88 CORRIDOR. CLOSER TO THE LAKE AND THE
CITY ICE AMOUNTS MAY BE LESS DUE TO THE FLOW OFF THE LAKE POSSIBLY
RESULTING IN TEMPS JUST ABOVE FREEZING. IT APPEARS THE MAIN ICING
THREAT WILL NOT OCCUR UNTIL TOMORROW AFTERNOON AND INTO THE
EVENING. THEREFORE...WE HAVE SOME TIME TO BETTER IRON OUT THE
AREAS MOST SUSCEPTIBLE TO ICING. WE WILL HIGHLIGHT THIS THREAT IN
AN SPS.
IT ALSO APPEARS THE HEAVY RAIN THREAT WILL MAINLY BE ACROSS MY
SOUTHEASTERN COUNTIES...SO NO CHANGES TO THE GOING FLOOD WATCH.
STRONG MOISTURE CONVERGENCE AND ANOMALOUSLY HIGH PWATS WILL LIKELY
PRODUCE AMOUNTS IN EXCESS OF AN INCH OR SO ACROSS THESE AREAS...AND
WITH ALL OF THIS BECOMING RUNOFF...RAPID RISES ON AREA STREAMS ARE
EXPECTED.
THE SNOW THREAT FOR AREAS SOUTH OF THE CURRENT WARNING AREA APPEAR
TO SOMEWHAT LIMITED...WITH A SHARP GRADIENT IN THE SNOW
ACCUMULATIONS EXPECTED. AN IMPRESSIVE DRY SLOT WILL PUNCH IN ACROSS
THE AREA LATE SATURDAY NIGHT INTO SUNDAY...LIKELY RESULT IN ONLY
LIGHT SNOW OR EVEN FZ DRIZZLE GIVEN THE LOSE OF ICE IN THE CLOUDS.
TOTAL SNOW AMOUNTS LOOK TO DROP TO UNDER AN INCH BY THE TIME YOU GET
CLOSE TO CHICAGO AND INTERSTATE 80.
MUCH COLDER AIR SPILLS IN ACROSS THE AREA SUNDAY NIGHT...WITH LIGHT
PRECIP CONTINUING IN ASSOCIATION WILL ANOTHER UPPER LEVEL
DISTURBANCE. TEMPERATURES WILL LIKELY DROP INTO THE SINGLE DIGITS
IN MOST AREAS SUNDAY NIGHT. THUS...ANY STANDING WATER
REMAINING...WITH LIKELY QUICKLY FREEZE IN PLACE ACROSS THE AREA.
KJB
EXTENDED FORECAST PERIOD /MONDAY MORNING THROUGH FRIDAY INCLUDING
THE CHRISTMAS HOLIDAY...
300 PM CST...
THE SENSIBLE WEATHER WILL QUIET CONSIDERABLY WITH THE MAIN FORECAST
CONCERNS FOCUSING ON TEMPERATURES AND THE CHANCE FOR SOME LIGHT
SNOW ON CHRISTMAS EVE AND EARLY CHRISTMAS DAY. THE GENERAL TREND
FOR THE EXTENDED FORECAST PERIOD WILL BE FOR MUCH BELOW NORMAL
TEMPERATURES WITH THE ONLY CHANCE FOR SOME LIGHT SNOW ON CHRISTMAS
EVE INTO CHRISTMAS DAY.
A HIGH AMPLITUDE LONGWAVE TROUGH IS EXPECTED TO CARVE OUT OVER THE
CNTRL CONUS WITH THE TROUGH AXIS EXTENDING FROM HUDSON BAY THROUGH
CENTRAL TEXAS. INITIALLY ON MONDAY...THE LOCAL AREA WILL SEE THE
TROUGH AXIS MOVING THROUGH THE AREA TRANSITIONING THE REGION FROM
RELATIVE WARM ADVECTION TO STRONG COLD ADVECTION. TEMPERATURES WILL
DROP OFF QUICKLY BY MONDAY MORNING...WITH LOWS EXPECTED TO DROP ONTO
THE SINGLE DIGITS WEST OF THE FOX VALLEY AND I-55 CORRIDOR. LOWS
OVER THE EASTERN PORTION OF THE FORECAST AREA SHOULD HANG IN THE
MIDDLE TO UPPER TEENS. AS THE LONGWAVE TROUGH CONTINUES TO THE ERN
CONUS MONDAY AND MONDAY NIGHT...WEAK UPPER RIDGING WILL BUILD ACROSS
THE UPPER MISSISSIPPI VALLEY...WITH THE AMPLITUDE OF THE UPPER LEVEL
PATTERN CONTINUING TO AMPLIFY. WITH DEEP LAYER FLOW REMAINING ON
THE NWLY FLOW SIDE OF THE UPPER RIDGE...TEMPERATURES WILL CONTINUE
TO DROP WITH LOWS TUESDAY MORNING BELOW ZERO OVER MUCH OF THE CWA...
GENERALLY WEST OF A LINE FROM WAUKEGAN TO PONTIAC...WITH THE
COLDEST AIR OVER THE ROCKFORD AREA WHERE TEMPS SHOULD BOTTOM OUT AT
-5F TO -10F. WIND CHILLS WILL BE A CONCERN AS WELL. WITH WINDS OF
5-10 KT LIKELY...WIND CHILLS WILL APPROACH THE -20F WIND CHILL
ADVISORY CRITERIA WEST OF THE FOX VALLEY AND I-55 CORRIDOR. BY
TUESDAY NIGHT...THE LONGER RANGE MODELS ARE ADVERTISING A PAIR OF
NORTHERN STREAM SHORTWAVES TRACKING ACROSS THE NRN PLAINS. THE
NRN-MOST WAVE...WHICH IS ALSO THE STRONGER OF THE PAIR...SHOULD
TRACK TO THE EAST...ACROSS THE UPPER GREAT LAKES WHILE THE MORE
SOUTHERLY...WEAKER WAVE DROPS THROUGH THE NRN PLAINS TO THE MIDDLE
MISSISSIPPI VALLEY. THIS THERE IS SOME DISCREPANCY AMONG THE LONGER
RANGE GUIDANCE ON THE SPEED OF PROGRESSION OF THIS WAVE...BUT THE
GENERAL CONSENSUS IS THAT THE WAVE WILL CROSS THE MIDDLE MISSISSIPPI
VALLEY...TRACKING OVER THE IL/WI BOARDER. FOLLOWING A PERIOD OF
STRONG COLD/DRY ADVECTION...THERE WILL BE LITTLE IN SITU MOISTURE
FOR THE SYSTEM TO WORK WITH AND WILL LARGELY HAVE TO RELY ON
DYNAMICS TO PRODUCE ANY PCPN. AT THIS POINT...ANTICIPATE THAT UPPER
DYNAMICS SHOULD BE STRONG ENOUGH TO PRODUCE AT LEAST SOME LIGHT SNOW
FOR LATE CHRISTMAS EVE INTO EARLY CHRISTMAS DAY. GIVEN THE LACK OF
DEEP LAYER MOISTURE OR ANY SIGNIFICANT LOW LEVEL MOISTURE TRANSPORT
AS FLOW THROUGH THE LOWER LEVELS SHOULD BE MORE WESTERLY AND UNABLE
TO TAP ANY GULF MOISTURE...ANY ACCUMULATIONS WILL LIKELY BE LIGHT.
A BRIEF PERIOD OF MORE WLY OR AT LEAST BROAD...FLAT TROUGHING SHOULD
COVER THE MIDWEST ON WEDNESDAY...ALLOWING FOR SOME MODERATION OF
TEMPERATURES ON WEDNESDAY AND THURSDAY...WITH HIGHS IN THE UPPER 20S
TO LOWER 30S ON WEDNESDAY AND UPPER TEENS TO MIDDLE 20S ON THURSDAY.
A REINFORCING SHOT OF COLD AIR ASSOCIATED WITH A STRONG NORTHERN
STREAM SHORTWAVE DIGGING INTO THE UPPER MISSISSIPPI VALLEY AND
SOUTHERN GREAT LAKES WILL BRING SUB-ZERO TEMPERATURES BACK TO MUCH
OF THE CWA FOR FRIDAY MORNING.
KREIN
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* IFR/LIFR CIGS CONTINUING OVERNIGHT AND LIKELY THROUGH
SATURDAY...THOUGH A BRIEF PERIOD OF MVFR IS POSSIBLE IN THE
MORNING.
* IFR VSBY AT MDW MAY IMPROVE SLIGHTLY LATER TONIGHT.
* TIMING AND TYPE OF PRECIP ONSET LATER TODAY.
MDB
//DISCUSSION...UPDATED 06Z...
ONE LOW PRESSURE AREA IS OFF TO THE EAST WHILE THE NEXT LOW
DEVELOPS OVER SOUTHWEST ARKANSAS. DRIZZLE/FREEZING DRIZZLE HAS
DIMINISHED IN COVERAGE DURING THE EVENING BUT VSBY HAS STRUGGLED
TO IMPROVE IN MANY AREAS...THOUGH ORD HAS IMPROVED TO GREATER THAN
6SM. SEVERAL SITES HAVE LOST SOME VSBY IN THE LAST HOUR OR SO
INCLUDING MDW SO WILL CARRY SOME LOWER VSBY THAN PREVIOUS TAFS TO
ACCOUNT FOR THIS. TOUGH TO SAY WHETHER THERE WILL BE MUCH
IMPROVEMENT OVERNIGHT DESPITE THE LACK OF DRIZZLE NOW OCCURRING SO
FURTHER ADJUSTMENTS MAY BE NEEDED. OTHERWISE EXPECT IFR/LIFR CIGS
TO PERSIST THROUGH THE MORNING.
THE ARKANSAS LOW WILL MOVE NORTHEAST TODAY SPREADING PRECIPITATION
NORTHWARD INTO THE AREA. -DZ/-FZDZ MAY DEVELOP AS UPWARD MOTION
BEGINS TO INCREASE MID/LATE MORNING. OTHERWISE CHANCES FOR MIXED
PRECIPITATION WILL INCREASE DURING THE AFTERNOON FROM SOUTH TO
NORTH...WITH RAIN/SNOW/SLEET ALL POSSIBLE. WITH SURFACE TEMPS
RIGHT AROUND FREEZING...SOME FREEZING RAIN MAY ALSO OCCUR. PRECIP
INTENSITY MAXIMIZES BY EARLY EVENING WITH WARMER AIR MOVING IN
ALOFT FAVORING MORE RAIN AT MDW/GYY WITH RAIN/SLEET POSSIBLE AT
ORD/DPA AND A TRANSITION FROM SNOW/SLEET TO SNOW AT RFD WHERE
TEMPS ALOFT WILL BE COLDER. DRIER AIR IS FORECAST TO MOVE IN ALOFT
DURING THE LATE EVENING HOURS WHICH WOULD LIKELY RESULT IN A LULL
IN PRECIP INTENSITY AND FAVOR -DZ/-FZDZ DEPENDING ON SURFACE
TEMPERATURE. RFD MAY REMAIN ON THE FRINGE OF THE DRY SLOT ALLOWING
FOR FLUCTUATIONS BETWEEN SNOW AND -FZDZ. WEST AND NORTHWEST WINDS
WILL TURN NORTHEAST LATER THIS MORNING AND INCREASE IN SPEED INTO
THE EVENING.
MDB
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* HIGH CONFIDENCE IN IFR/LIFR CIGS CONTINUING OVERNIGHT. LOW
CONFIDENCE IN ANY IMPROVEMENT TO MVFR CIGS.
* LOW-MEDIUM CONFIDENCE IN SOME VSBY IMPROVEMENT AT MDW
OVERNIGHT.
* MEDIUM CONFIDENCE IN TIMING/PRECIP TYPE TRENDS LATER TODAY.
MDB
//OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z...
SUNDAY...SNOW ESPECIALLY IN THE MORNING. IFR LIKELY. BRIEF LIFR
POSSIBLE EARLY.
MONDAY...CHANCE OF SNOW SHOWERS. MVFR/IFR POSSIBLE.
TUESDAY...VFR.
WEDNESDAY...CHANCE OF LIGHT SNOW. MVFR/IFR POSSIBLE.
THURSDAY...SLIGHT CHANCE OF LIGHT SNOW. MVFR POSSIBLE.
RATZER
&&
.MARINE...
218 PM...LOW PRESSURE OVER CENTRAL ILLINOIS WILL MOVE NORTHEAST
ACROSS THE EASTERN LAKES TONIGHT AS IT SLOWLY WEAKENS AS WEAK HIGH
PRESSURE OVER THE UPPER MIDWEST IS ABSORBED BY STRONGER HIGH
PRESSURE MOVING ACROSS SOUTHERN CANADA SATURDAY AND SATURDAY
NIGHT. THE GRADIENT WILL SLOWLY WEAKEN TONIGHT WITH SPEEDS IN THE
10-15 KT RANGE BY MORNING. NEW LOW PRESSURE WILL DEVELOP OVER
TEXAS TONIGHT AND MOVE NORTHEAST TO NORTHERN INDIANA BY SUNDAY
MORNING. AS THIS LOW APPROACHES THE LAKES REGION...IT WILL DEEPEN
AND THE GRADIENT WILL TIGHTEN BETWEEN THE STRONGER HIGH ACROSS
SOUTHERN CANADA. NORTHEAST WINDS WILL STEADILY INCREASE SATURDAY
EVENING WITH 30 KTS EXPECTED. DEPENDING ON THE EXACT STRENGTH AND
TRACK OF THIS LOW...ITS POSSIBLE THERE COULD BE A PERIOD OF LOW
END GALES BUT CONFIDENCE IS TOO LOW TO INCLUDE IN THIS FORECAST. A
TROUGH OF LOW PRESSURE WILL THEN LINGER ACROSS THE WESTERN LAKES
REGION SUNDAY NIGHT WITH NORTHERLY WINDS SHIFTING NORTHWESTERLY.
STRONG HIGH PRESSURE WILL BUILD ACROSS THE PLAINS SUNDAY AND
SUNDAY NIGHT AND THEN SHIFT EAST ACROSS THE LAKES REGION MONDAY
NIGHT AND TUESDAY. THERE IS A POTENTIAL FOR A PERIOD OF STRONG
WINDS AHEAD OF THE HIGH...IN THE MONDAY/MONDAY NIGHT TIME PERIOD.
BUT CONFIDENCE REGARDING SPECIFICS DURING THIS TIME PERIOD REMAIN
LOW. CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WINTER STORM WARNING...ILZ003-ILZ004-ILZ005-ILZ008-ILZ010-
ILZ011...6 PM SATURDAY TO 6 PM SUNDAY.
WINTER STORM WATCH...ILZ006-ILZ012...6 PM SATURDAY TO 6 PM
SUNDAY.
FLOOD WATCH...ILZ033-ILZ039...NOON SATURDAY TO 6 AM SUNDAY.
IN...FLOOD WATCH...INZ010-INZ011-INZ019...NOON SATURDAY TO 6 AM
SUNDAY.
LM...NONE.
&&
$$
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AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
950 PM EST SUN DEC 22 2013
.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 245 PM EST SUN DEC 22 2013
AS THE MAJOR RAINMAKER CONTINUES TO MOVE QUICKLY AWAY FROM THE
AREA...UPPER LEVEL FLOW WILL REMAIN STRONGLY CYCLONIC AS HIGH
PRESSURE BUILDS INTO THE AREA. RESIDUAL LOW LEVEL MOISTURE AND
THIS CYCLONIC FLOW MAY BE ABLE TO SQUEEZE OUT A FEW FLURRIES AT
TIMES...BUT NOTHING OF SIGNIFICANCE.
&&
.NEAR TERM /OVERNIGHT/...
ISSUED AT 950 PM EST SUN DEC 22 2013
LOW STRATUS DECK REMAINS THIS EVENING ALONG WITH A FEW FLURRIES
AND POCKETS OF LIGHT DRIZZLE. TEMPS CONTINUE TO SLOWLY BUT
STEADILY FALL AS THE COLDER AIR SEEPS INTO THE REGION FROM THE
WEST. MOST LOCATIONS WERE IN THE LOWER AND MIDDLE 30S AS OF 0230Z.
ONLY SUBTLE ADJUSTMENTS NEEDED FOR THE EVENING UPDATE. EXPECT
CLOUDS TO LINGER ALL NIGHT WITH STRATUS DECK ALL THE WAY BACK TO
THE WEST OF THE MISSISSIPPI RIVER. FURTHERMORE...PRESENCE OF THE
SLOW MOVING FRONTAL BOUNDARY ACROSS THE APPALACHIANS IS DELAYING
EXPANSION OF HIGH PRESSURE EAST INTO THE OHIO VALLEY. DECIDED TO
EXTEND CHANCES FOR FLURRIES THROUGH THE NIGHT AS WEAK INSTABILITY
NOTED BENEATH THE INVERSION ON RAP SOUNDINGS AND FORCING ALOFT
PRESENT. POCKETS OF DRIZZLE REMAIN POSSIBLE OVER EASTERN COUNTIES
FOR THE DURATION OF THE EVENING BUT EXPECT A CHANGE TO FLURRIES IN
THESE AREAS AS THE BOUNDARY LAYER COOLS. OVERNIGHT LOWS IN THE
20S LOOK REASONABLE.
ZONE AND GRID UPDATES OUT.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
ISSUED AT 245 PM EST SUN DEC 22 2013
SURFACE HIGH PRESSURE WILL DOMINATE THE SHORT TERM
PERIOD...ALTHOUGH AN UPPER LEVEL TROUGH AXIS WILL SWING THROUGH
THE AREA TOMORROW NIGHT. WILL CARRY A SLIGHT CHANCE OF FLURRIES
LATE TOMORROW INTO TOMORROW NIGHT...BUT AGAIN NO MEASURABLE POP AS
MOISTURE IS LACKING TO SAY THE LEAST.
ON TEMPS...CONSENSUS NUMBERS LOOK VERY REASONABLE GIVEN EXPECTED
LOW LEVEL THICKNESSES. FEW TWEAKS WERE REQUIRED BUT GENERALLY
STUCK CLOSE TO THESE NUMBERS.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
ISSUED AT 240 PM EST SUN DEC 22 2013
NO MAJOR WEATHER CONCERNS FOR THE EXTENDED WHICH SHOULD ALLOW RIVER
FLOODING TO RUN ITS COURSE. THAT BEING SAID...MODELS IN GENERAL
AGREEMENT THAT TWO DIFFERENT SYSTEMS WILL BRING POTENTIAL FOR MINOR
PRECIPITATION WEDNESDAY NIGHT AND THURSDAY AS WELL AS SUNDAY.
SO...KEPT SMALL REGIONAL ALLBLEND POPS. IT SHOULD BE COLD ENOUGH FOR
ONLY SNOW AS PRECIPITATION TYPE WEDNESDAY NIGHT AND THURSDAY...BUT
SOUTHWEST FLOW AHEAD OF LATE WEEKEND FRONTAL SYSTEM SUGGESTS
POSSIBILITY EXISTS OF A MIX OF RAIN AND SNOW IF NOT JUST RAIN.
ALLBLEND TEMPERATURES LOOK REASONABLE WITH AFTERNOON TEMPERATURES
STARTING OFF IN THE 20S AND 30S AND THEN WARMING TO THE 30S AND 40S
BY SATURDAY.
&&
.AVIATION /DISCUSSION FOR THE 230300Z KIND TAF UPDATE/...
ISSUED AT 920 PM EST SUN DEC 22 2013
NO SIGNIFICANT CHANGES MADE TO THE FORECAST AT THIS TIME. PREVIOUS
DISCUSSION FOLLOWS.
WIDESPREAD MVFR CEILINGS AROUND 012 CURRENTLY ACROSS THE AREA
EXPECTED TO CONTINUE AT THE TAF SITES TONIGHT AS MOISTURE REMAINS
TRAPPED BELOW AN INVERSION. SOME BRIEF PERIODS OF IFR CEILINGS
008-009 AGL ALONG WITH SOME VISIBILITY RESTRICTIONS IN LIGHT DRIZZLE
OR LIGHT SNOW POSSIBLE TONIGHT AS AN UPPER TROUGH MOVES
THROUGH...BUT THESE CONDITIONS SHOULD NOT BE TOO WIDESPREAD OR
PROLONGED IN NATURE.
SURFACE WINDS GENERALLY AT OR BELOW 12 KTS THROUGH 231200Z.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...NIELD
NEAR TERM...RYAN
SHORT TERM...NIELD
LONG TERM...MK
AVIATION...JAS
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AREA FORECAST DISCUSSION
NWS GOODLAND KS
635 PM MST SUN DEC 22 2013
.UPDATE...
ISSUED AT 630 PM MST SUN DEC 22 2013
AT 0130Z LIGHT SNOW WAS BEING REPORTED PER AWOS OB AT WRAY
COLORADO WITH YUMA WEBCAM SHOWING WHAT APPEARS TO BE LIGHT RAIN.
TEMPERATURES IN THAT AREA CURRENTLY AROUND 36-37F. DESPITE RATHER
LARGE T/TD SPREADS PRECIP IS REACHING THE GROUND.
FOR THE LATEST UPDATE ADJUSTED TEMPERATURES/DEWPOINTS AND WINDS
BASED ON CURRENT OBS AND 23Z HRRR WHICH HAS A VERY GOOD HANDLE ON
CURRENT SITUATION.
COMBINATION OF LOW LEVEL FORCING FROM WIND SHIFT ASSOCIATED WITH
APPROACHING COLD FRONT AND UPPER DISTURBANCE PRODUCING LIGHT
RAIN/SNOW FROM YUMA EAST THROUGH PARTS OF FAR SOUTHWEST NEBRASKA.
CURRENT TREND ON TRACK WITH LATEST FORECAST...ADJUSTMENT WAS MADE
TO UP THE POPS FASTER ACROSS THE FAR NORTH.
WILL AWAIT THE 00Z RUC/HRRR/NAM BEFORE MAKING FURTHER ADJUSTMENTS
THIS EVENING.
UPDATE ISSUED AT 410 PM MST SUN DEC 22 2013
UPDATE REQUIRED TO PUSH BACK ONSET OF SNOWFALL...ESPECIALLY EARLY
TONIGHT. PREVIOUS FORECAST HAD SNOW ALREADY FALLING ACROSS THE
NORTHWEST PORTION OF THE AREA. LATEST MODEL UPDATES...RADAR AND
SFC OBS SHOW SNOW WELL TO THE NORTHWEST OF THE AREA. NOT EXPECTING
ANY PRECIP TO DEVELOP IN THE FORECAST AREA FOR ANOTHER FEW HOURS.
THERE IS ALSO SOME AGREEMENT THAT THERE WILL BE TWO SEPARATE AREAS
OF PRECIPITATION FOCUS...THE FIRST MOVES DOWN FROM WESTERN
NEBRASKA/FAR NORTHEAST COLORADO SLIDING SOUTHEAST AND MAINLY
IMPACTING THE THE NORTHERN THROUGH EASTERN PARTS OF THE AREA. A
SECOND LESS DYNAMIC SYSTEM MOVES DOWN INTO EASTERN COLORADO. THE
HEIGHT OF THE PRECIPITATION AND BEST CHANCE FOR LIGHT SNOWFALL
ACCUMULATIONS WILL BE IN THE 02Z-11Z TIMEFRAME WITH A QUICKLY
DECREASE SHORTLY THEREAFTER. STILL LOOKING AT TOTAL SNOWFALL
AMOUNTS UP TO AN INCH AND A HALF...MAYBE TWO INCHES PRIMARILY
ALONG AND NORTH OF THE KS/NE BORDER WITH DECREASING AMOUNTS AS ONE
TRAVELS SOUTH. FOR THE FAR SOUTHWEST AND SOUTHERN PARTS OF THE
AREA NO SNOWFALL IS EXPECTED AT THIS TIME.
MAY HAVE SOME GUSTY NORTHEAST WINDS TO 25 MPH TONIGHT AS WELL
POSSIBLY CREATING A BIT OF BLOWING SNOW.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 1217 PM MST SUN DEC 22 2013
A NORTHERN STREAM TROUGH WILL PASS THROUGH THE REGION TONIGHT AS A
IT MOVES EAST TOWARD THE GREAT LAKES. A SHORTWAVE WILL DIVE SOUTH ON
THE WEST SIDE OF THE TROUGH ACROSS NORTHWEST KANSAS. NORTHWEST FLOW
WILL FOLLOW ON MONDAY WITH SHORTWAVE RIDGING AND SUBSIDENCE. A
SURFACE COLD FRONT WILL MOVE INTO THE CENTRAL PLAINS TONIGHT WITH
HIGH PRESSURE BUILDING INTO THE REGION MONDAY.
THE SHORTWAVE THAT COMES THROUGH THE FLOW TONIGHT HAS FAVORABLE
PARAMETERS FOR SOME LIGHT SNOW ACROSS MAINLY THE NORTHERN HALF OF
THE FA. FORCING AND ADEQUATE MOISTURE ARE INDICATED AND FORECAST
SOUNDINGS SHOW ICE IN THE COLUMN. MODELS INDICATE THAT SNOW SHOULD
BE ENDING QUICKLY AROUND 12Z MONDAY. TOTAL AMOUNTS SHOULD RANGE
GENERALLY LESS THAN AN INCH AROUND THE I-70 CORRIDOR WITH 1 TO 2
INCHES NORTH OF THE INTERSTATE. SNOW SHOULD BEGIN BY LATE EVENING
ACROSS THE NORTH AND THEN SPREAD SOUTHEAST THROUGH THE REST OF THE
NIGHT. SNOW AMOUNTS AND WIND SHOULD BE BELOW ADVISORY CRITERIA.
SUBSIDENCE WILL MOVE INTO THE FA BEHIND THE WAVE ON MONDAY WITH
CLEARING SKIES.
MIN TEMPERATURES TONIGHT WILL FALL INTO THE TEENS. MAX TEMPERATURES
MONDAY WILL RANGE FROM THE LOWER 20S IN THE EAST TO LOW 30S IN THE
WEST.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 155 PM MST SUN DEC 22 2013
DRY AND MILD THROUGH THE LONG TERM WITH A FEW WEAK COLD FRONTS
DURING THE WEEK. ONLY CHANCE OF PRECIP IN THE LONG TERM LOOKS TO BE
ON SATURDAY NIGHT INTO SUNDAY.
MON NIGHT...HIGH PRESSURE WILL BE IN PLACE ACROSS THE CENTRAL AND
NORTHERN PLAINS AS SOUTHWESTERLY MID-LEVEL FLOW BRINGS SOMEWHAT
MILDER AIR TO THE HIGH PLAINS. LOWS WILL BE NEAR NORMAL.
TUESDAY...MILD AS A COLD FRONT APPROACHES FROM THE NORTHWEST. H5
SHORTWAVE RIDGE WILL MOVE ACROSS THE CENTRAL TO NORTHERN PLAINS. AT
THE SURFACE A LEE SIDE TROUGH WILL DEVELOP IN EASTERN COLORADO
DURING THE AFTERNOON WITH THE PRESSURE GRADIENT SUPPORTING A MILD
BREEZE OUT OF THE SOUTH/SOUTHWEST. INCREASING CLOUDS DURING THE
MORNING AND INTO THE AFTERNOON. COLD FRONT WILL MOVE THROUGH IN THE
AFTERNOON BRINGING A WIND SHIFT AND CLEARING SKIES. NAM/NAM 4KM NEST
SPEEDS UP THE FRONTAL TIMING...SO TUESDAY HAS THE POTENTIAL TO TURN
OUT EVEN SUNNIER THAN CURRENTLY FORECAST. REGARDLESS OF
TIMING...PRECIP CHANCES ARE NEAR NIL.
TUESDAY NIGHT...CHRISTMAS EVE...AIR MASS BEHIND THE FRONT IS COOL
AND DRY...AND THUS PRECIPITATION IS NOT EXPECTED. WINDS BECOME LIGHT
BEYOND THE FRONT...AND SKIES WILL BE MOSTLY CLEAR.
WEDNESDAY...CHRISTMAS...SUNNY AND SEASONABLE WITH LIGHT WINDS. HIGH
PRESSURE WILL AGAIN BUILD ACROSS THE CENTRAL PLAINS IN THE WAKE OF
TUESDAY NIGHTS WEAK COLD FRONT...WITH HIGH TEMPS EXPECTED TO BE NEAR
TO ABOVE NORMAL /MID 40S/.
IN THE EXTENDED /WED NIGHT THRU SATURDAY NIGHT/...DRY AND MILD FOR
THE MOST PART WITH CHANCE OF PRECIP OVER THE WEEKEND. A REINFORCING SHOT OF
COLD AIR WILL DROP THROUGH THE NORTHERN PLAINS ON WED NIGHT INTO
THURSDAY...BUT THIS LOOKS TO BE TRENDING FARTHER EAST WITH EACH RUN
OF GUIDANCE. THUS...EXPECT THIS AIR MASS NOT TO EFFECT THE CWA AND
TEMPS TO BE MILD THURSDAY FRIDAY AND SATURDAY. FRI AND SAT LOOK
ESPECIALLY MILD...WITH 850MB TEMPS ABOUT 10 DEG C ABOVE NORMAL AND
SOUTHWESTERLY FLOW FROM THE SURFACE TO ABOUT 850MB. ON SATURDAY
NIGHT A COLD FRONT WILL APPROACH FROM THE NORTH...WHICH WILL BRING A
CHANCE OF PRECIP AND COLDER AIR. SET UP DOES NOT LOOK ESPECIALLY
VIGOROUS...BUT AT THIS POINT LOOKS TO BE THE BEST CHANCE FOR PRECIP
THE AREA HAS SEEN IN A WHILE.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 423 PM MST SUN DEC 22 2013
VFR CONDITIONS WILL BEGIN THE TAF PERIOD...THEN DROP TO MVFR WITH
THE COLD FRONT AND UPPER DISTURBANCE MOVING THROUGH BRINGING A
CHANCE FOR SNOW. IFR CEILINGS ARE ALSO POSSIBLE...WITH IFR
VISIBILITY OVER KMCK...ACCOMPANYING THE LIGHT SNOW TONIGHT.
FOR KGLD...BUFKIT SOUNDINGS AND MODELS SHOW VFR DECREASING TO MVFR
AROUND 05Z WITH LIGHT SNOW. THE BEST CHANCE FOR LIGHT SNOW APPEARS
TO BE BETWEEN 06Z AND 10Z...SO INCLUDED A TEMPO GROUP FOR IFR
CEILINGS SINCE THEY COULD FLUCTUATE DURING THE TIME PERIOD. VISIBILITY
SHOULD REMAIN AROUND 6SM SINCE SNOW WILL BE VERY LIGHT...BUT
INCLUDED 4SM IN TEMPO GROUP FOR FLUCTUATIONS OF SLIGHTLY HEAVIER SNOWFALL.
SNOW SHOULD COME TO AN END AROUND 12Z WITH VFR CONDITIONS RESUMING
AROUND 15Z.
FOR KMCK...SOUNDINGS AND MODELS SHOW LIGHT SNOW MOVING INTO THE TERMINAL
BETWEEN 02 AND 03Z...SO INCLUDED A TEMPO GROUP FOR WHEN THE SNOW
STARTS OVER KMCK. CEILINGS WILL ALSO START TO LOWER TO MVFR AROUND
THIS TIME. BETTER FORCING WILL OCCUR OVER KMCK...SO INCLUDED A
TEMPO GROUP FOR CEILINGS LOWERING TO IFR AND VISIBILITY LOWERING
TO IFR AT 2SM WITH THE HEAVIER SNOW THAT MOVES THROUGH. SNOW IS ALSO
EXPECTED TO COME TO AN END AROUND 12Z...WITH CEILINGS REMAINING
MVFR THROUGH 18Z. CONDITIONS WILL IMPROVE TO VFR AROUND 18Z.
CONSIDERING SOUNDINGS WERE A LITTLE MISLEADING ON PREVIOUS DAYS
AND GUIDANCE IS NO HELP WHAT-SO-EVER...AMENDMENTS WILL BE MADE AS
CHANGES TAKE PLACE.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...99
SHORT TERM...FS
LONG TERM...JJM
AVIATION...ALW
AREA FORECAST DISCUSSION...UPDATED
NWS DODGE CITY KS
1112 AM CST Sat Dec 21 2013
...Updated for Aviation...
.SHORT TERM...(This evening through Saturday)
ISSUED AT 355 AM CST SAT DEC 21 2013
A strong shortwave trough centered west of El Paso early this
morning will eject northeastward across the southern plains through
this evening. Plenty of low level moisture was being ejected into
this system from the south. The deformation/trowal will set up
across southwestern Kansas later today and the 06z NAM and 00 UTC
ECMWF seem to have the best handle on the distribution and amounts
of snow. Given that this is a fast moving system, snow totals of 2
to 5 inches are generally expected in the advisory area along and
southeast of a line from Elkhart to Garden City to Ness City to
LaCrosse, with the highest amounts from Meade eastward into Barber
and Pratt counties. A few locations could reach 6 inches. The snow
may start off as sleet or freezing rain in south central Kansas
later this morning since RAP soundings show an elevated warm layer
around 1C through 18Z. Temperatures may rise into the upper 20s and
lower 30s before the snow arrives, and then fall back into the mid
20s. Afternoon temperatures will be warmer in places like Syracuse,
Scott City and Dighton where not much in the way of snow is
expected. Temperatures tonight will be held up by 10kt north winds
and cloud cover; but with fairly chilly air pushing southward out of
the northern plains in the wake of the storm system, temperatures
should drop into the teens.
.LONG TERM...(Sunday through Friday)
ISSUED AT 246 AM CST SAT DEC 21 2013
Models this morning were in fairly good agreement with lifting a
weakening upper level trough across the Mid Mississippi Valley on
Sunday. At the same time a northern branch upper level trough will
move out of the Rockies and across the Central Plains as an area
of high pressure at the surface builds into western Kansas.
Although no measurable precipitation is expected with this next
system, there will be some increasing clouds late Sunday into
Sunday night. This increasing cloud cover will limit how cold
temperatures will fall Sunday night, however give light winds and
fresh snow cover across western Kansas will still undercut the
coolest guidance for overnight lows. Temperatures falling back
into the single digits still looks reasonable. Lows near zero no
out of the question near the Oklahoma border if skies remain clear
for several hours after midnight.
Westerly downslope flow will improve early next week which will
allow temperatures to gradually warm. Snow cover will limit how
much warming will occur Monday and Tuesday, but at this time the
latest CRExtendFcst_Init still looks reasonable. Where the heavier
snowfall is expected later today the afternoon temperatures are
expected to warm into the upper 30s by Tuesday afternoon.
Elsewhere highs in the mid to upper 40s still appear likely given
the 850mb temperature trends from the GFS and ECMWF. This slow
warming trend will briefly end mid week as a cold front drops
south across Kansas Tuesday night Wednesday.
&&
.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
ISSUED AT 1107 AM CST SAT DEC 21 2013
The track of the upper level storm and attendant heavy snow axis
is forecast to be just east of the KDDC terminal. Some MVFR conditions
are possible mainly at KDDC with light snow and north winds around
10kts after 19Z through around 05Z before the snow moves off to
the east.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 30 18 28 4 / 80 90 0 0
GCK 31 18 29 9 / 20 20 0 0
EHA 28 18 32 17 / 50 40 0 0
LBL 28 18 29 11 / 80 40 0 0
HYS 32 16 28 10 / 20 30 10 20
P28 29 19 27 3 / 100 100 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY until Midnight CST tonight FOR KSZ046-
063>066-075>081-084>090.
&&
$$
SHORT TERM...Finch
LONG TERM...Burgert
AVIATION...Kruse
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
507 AM CST Sat Dec 21 2013
...Updated aviation discussion...
.SHORT TERM...(This evening through Saturday)
ISSUED AT 355 AM CST SAT DEC 21 2013
A strong shortwave trough centered west of El Paso early this
morning will eject northeastward across the southern plains through
this evening. Plenty of low level moisture was being ejected into
this system from the south. The deformation/trowal will set up
across southwestern Kansas later today and the 06z NAM and 00 UTC
ECMWF seem to have the best handle on the distribution and amounts
of snow. Given that this is a fast moving system, snow totals of 2
to 5 inches are generally expected in the advisory area along and
southeast of a line from Elkhart to Garden City to Ness City to
LaCrosse, with the highest amounts from Meade eastward into Barber
and Pratt counties. A few locations could reach 6 inches. The snow
may start off as sleet or freezing rain in south central Kansas
later this morning since RAP soundings show an elevated warm layer
around 1C through 18Z. Temperatures may rise into the upper 20s and
lower 30s before the snow arrives, and then fall back into the mid
20s. Afternoon temperatures will be warmer in places like Syracuse,
Scott City and Dighton where not much in the way of snow is
expected. Temperatures tonight will be held up by 10kt north winds
and cloud cover; but with fairly chilly air pushing southward out of
the northern plains in the wake of the storm system, temperatures
should drop into the teens.
.LONG TERM...(Sunday through Friday)
ISSUED AT 246 AM CST SAT DEC 21 2013
Models this morning were in fairly good agreement with lifting a
weakening upper level trough across the Mid Mississippi Valley on
Sunday. At the same time a northern branch upper level trough will
move out of the Rockies and across the Central Plains as an area
of high pressure at the surface builds into western Kansas.
Although no measurable precipitation is expected with this next
system, there will be some increasing clouds late Sunday into
Sunday night. This increasing cloud cover will limit how cold
temperatures will fall Sunday night, however give light winds and
fresh snow cover across western Kansas will still undercut the
coolest guidance for overnight lows. Temperatures falling back
into the single digits still looks reasonable. Lows near zero no
out of the question near the Oklahoma border if skies remain clear
for several hours after midnight.
Westerly downslope flow will improve early next week which will
allow temperatures to gradually warm. Snow cover will limit how
much warming will occur Monday and Tuesday, but at this time the
latest CRExtendFcst_Init still looks reasonable. Where the heavier
snowfall is expected later today the afternoon temperatures are
expected to warm into the upper 30s by Tuesday afternoon.
Elsewhere highs in the mid to upper 40s still appear likely given
the 850mb temperature trends from the GFS and ECMWF. This slow
warming trend will briefly end mid week as a cold front drops
south across Kansas Tuesday night Wednesday.
&&
.AVIATION...(For the 12Z TAFS through 12Z Sunday morning)
ISSUED AT 505 AM CST SAT DEC 21 2013
Clouds will thicken and lower today with low VFR cigs expected to
develop after 15z at DDC and GCK. MVFR cigs are then expected to
develop by 21z. With the lowering cigs some light snow is also
expected to develop with a period of steady light snow appearing
most likely between 21z and 03z. At HYS cigs will also be lowering
through the day, however based on the 06z NAM BUFR soundings VFR
cigs are expected today and early tonight. North winds will
continue at 10 knots or less at all three taf sites.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 30 18 28 4 / 90 90 0 0
GCK 31 18 29 9 / 50 30 0 0
EHA 28 18 32 17 / 90 20 0 0
LBL 28 18 29 11 / 100 40 0 0
HYS 32 16 28 10 / 40 60 10 20
P28 29 19 27 3 / 100 90 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY until Midnight CST tonight FOR KSZ046-
063>066-075>081-084>090.
&&
$$
SHORT TERM...Finch
LONG TERM...Burgert
AVIATION...Burgert
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
355 AM CST Sat Dec 21 2013
...Updated for short term discussion...
.SHORT TERM...(This evening through Saturday)
ISSUED AT 355 AM CST SAT DEC 21 2013
A strong shortwave trough centered west of El Paso early this
morning will eject northeastward across the southern plains through
this evening. Plenty of low level moisture was being ejected into
this system from the south. The deformation/trowal will set up
across southwestern Kansas later today and the 06z NAM and 00 UTC
ECMWF seem to have the best handle on the distribution and amounts
of snow. Given that this is a fast moving system, snow totals of 2
to 5 inches are generally expected in the advisory area along and
southeast of a line from Elkhart to Garden City to Ness City to
LaCrosse, with the highest amounts from Meade eastward into Barber
and Pratt counties. A few locations could reach 6 inches. The snow
may start off as sleet or freezing rain in south central Kansas
later this morning since RAP soundings show an elevated warm layer
around 1C through 18Z. Temperatures may rise into the upper 20s and
lower 30s before the snow arrives, and then fall back into the mid
20s. Afternoon temperatures will be warmer in places like Syracuse,
Scott City and Dighton where not much in the way of snow is
expected. Temperatures tonight will be held up by 10kt north winds
and cloud cover; but with fairly chilly air pushing southward out of
the northern plains in the wake of the storm system, temperatures
should drop into the teens.
.LONG TERM...(Sunday through Friday)
ISSUED AT 246 AM CST SAT DEC 21 2013
Models this morning were in fairly good agreement with lifting a
weakening upper level trough across the Mid Mississippi Valley on
Sunday. At the same time a northern branch upper level trough will
move out of the Rockies and across the Central Plains as an area
of high pressure at the surface builds into western Kansas.
Although no measurable precipitation is expected with this next
system, there will be some increasing clouds late Sunday into
Sunday night. This increasing cloud cover will limit how cold
temperatures will fall Sunday night, however give light winds and
fresh snow cover across western Kansas will still undercut the
coolest guidance for overnight lows. Temperatures falling back
into the single digits still looks reasonable. Lows near zero no
out of the question near the Oklahoma border if skies remain clear
for several hours after midnight.
Westerly downslope flow will improve early next week which will
allow temperatures to gradually warm. Snow cover will limit how
much warming will occur Monday and Tuesday, but at this time the
latest CRExtendFcst_Init still looks reasonable. Where the heavier
snowfall is expected later today the afternoon temperatures are
expected to warm into the upper 30s by Tuesday afternoon.
Elsewhere highs in the mid to upper 40s still appear likely given
the 850mb temperature trends from the GFS and ECMWF. This slow
warming trend will briefly end mid week as a cold front drops
south across Kansas Tuesday night Wednesday.
&&
.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
ISSUED AT 1202 AM CST SAT DEC 21 2013
A strong upper level system will pass across Oklahoma on Saturday.
CIGS will lower to IFR at KDDC as snow develops by 18-21z, with
visibilities as low as 1 mile in the heaviest snow between 21-24z.
KHYS and KGCK will be on the edge of the precipitation shield so
that only minor restrictions to visibility to 1-3 miles are
expected. The snow will be ending after 02z and ceilings and
visibilities will dramatically improve.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 30 17 28 4 / 90 90 0 0
GCK 31 18 29 9 / 50 30 0 0
EHA 28 20 32 17 / 90 20 0 0
LBL 28 18 29 11 / 100 40 0 0
HYS 32 16 28 10 / 40 60 10 20
P28 29 17 27 3 / 100 90 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY until Midnight CST tonight FOR KSZ045-
046-063>066-075>081-084>090.
&&
$$
SHORT TERM...Finch
LONG TERM...Burgert
AVIATION...Finch
AREA FORECAST DISCUSSION
NWS JACKSON KY
306 AM EST SAT DEC 21 2013
.UPDATE...
ISSUED AT 119 AM EST SAT DEC 21 2013
BASED ON RECENT TRENDS...UPDATED TO LOWER WINDS SLIGHTLY OVERNIGHT AND TO
RAISE MIN TEMPS A BIT.
UPDATE ISSUED AT 1100 PM EST FRI DEC 20 2013
CURRENT CONDITIONS ACROSS THE AREA AS OF 04Z FEATURE SOME SCATTERED
SHOWERS MOVING NORTHEAST FROM TN INTO THE SOUTH CENTRAL AND SOUTHERN
I-75 CORRIDOR OF KENTUCKY. GENERALLY...THE NAM AND HRRR ARE AGREEING
ON ISOLATED TO SCATTERED SHOWERS SKIRTING THE WESTERN EXTEND OF THE
CWA...OR I-75 CORRIDOR THROUGH THE REST OF THE NIGHT. THE BEST LIFT
AND MOISTURE ARRIVES IN THE NORTHWEST IN THE 09Z TO 12Z TIME FRAME AND
IF THERE EVER IS A CHANCE FOR THUNDER TONIGHT...IT WILL OCCUR DURING
THIS PERIOD IN THE PREDAWN HOURS AND KEPT A SLIGHT CHANCE IN THE
FORECAST DUE TO THE LACK OF LIFT AND MOISTURE AT THIS TIME. HAVE
UPDATED AND SENT OUT A FRESH ZFP TO ACCOUNT FOR THIS ADJUSTMENT AND
LOADED CURRENT OBSERVATIONS AND SENT GRIDS TO NDFD.
UPDATE ISSUED AT 830 PM EST FRI DEC 20 2013
AS OF 0130Z SOME SHOWERS ARE BEGINNING TO DEVELOP AND MOVE INTO THE
AREA FROM THE SOUTH AS THE MOISTURE SURGE AND LIFT DEVELOPS AND MOVES
IN FROM THE SOUTHWEST. UPDATED THE GRIDS WITH THE MOST CURRENT OBS
AND HAVE SENT THEM TO NDFD. THE REST OF THE FORECAST IS ON TRACK.
UPDATE ISSUED AT 715 PM EST FRI DEC 20 2013
CURRENT CONDITIONS ACROSS THE AREA FEATURE A FEW STRAY SHOWERS
PASSING THROUGH EASTERN KENTUCKY BUT OTHERWISE ANY MEASURABLE PRECIP
LOOKS TO BE NONEXISTENT FOR AT LEAST THE NEXT COUPLE OF HOURS SO AT
THIS POINT...SLIGHT CHANCE SHOWERS LOOK TO BE THE WAY TO GO AND THEN
AS LIFT AND MOISTURE SURGE INCREASES TONIGHT...WILL INTRODUCE SOME
CHANCE AND LIKELY SHOWERS WITH AT LEAST SOME NOTICEABLE ISENTROPIC
LIFT JUST SKIRTING TO THE WEST OF THE I-75 CORRIDOR...WILL LEAVE
SLIGHT CHANCE THUNDERSTORMS JUST IN THE WESTERN ZONES AND ONLY
STARTING IN THE PREDAWN HOURS. HAVE ADJUSTED FOR PRECIP CHANCES
ARRIVING LATER SO A FRESH ZFP HAS BEEN ISSUED FOR THESE SLIGHT
CHANGES. OTHERWISE...HAVE LOADED IN THE LATEST OB AND SENT THE GRIDS
TO NDFD.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 359 PM EST FRI DEC 20 2013
ISOLATED TO SCATTERED SHOWERS HAVE BEEN MOVING ACROSS EASTERN
KENTUCKY TODAY. A FRONTAL SYSTEM EXTENDS FROM SOUTHERN MICHIGAN TO
NORTH CENTRAL TEXAS AND HAS MULTIPLE WAVES MOVING ALONG IT. THIS
WILL RESULT IN THE FRONT BOWING TO THE NORTH AHEAD OF THE LOW AND
THEN BOWING DOWN ON THE BACK SIDE OF THE LOW. THIS WILL CAUSE THE
FRONTS TO MOVE PRECIPITATION IN AND OUT OF THE AREA. THE COLD FRONT
WILL FINALLY MOVE THROUGH THE AREA ON SUNDAY WHEN THE UPPER TROUGH
MOVES TO THE WEST AND NORTH OF THE AREA. THE LATEST MODEL RUNS ARE
MOVING THE FRONT THROUGH THE AREA ON SUNDAY MORNING. THERE WILL BE A
STRONG LOW LEVEL JET OUT AHEAD OF THE FRONT. THE JET WILL BE MOVING
INTO THE AREA ON SATURDAY NIGHT. PUT OUT A LAKE WIND ADVISORY TO
COVER THE WIND GUSTS EXPECTED WITH THIS SYSTEM. IT IS POSSIBLE THAT
THIS MAY HAVE TO BE UPGRADED TO A WIND ADVISORY...HOWEVER SINCE IT
WILL BE NIGHT TIME...IT WILL BE HARDER TO MIX THE STRONGER GUSTS DOWN
TO THE SURFACE. THE UPPER ELEVATIONS WOULD BE MOST LIKELY TO SEE THE
STRONGEST GUSTS. THE SEVERE WEATHER THREAT IS ALSO MINIMIZED DUE TO
THE TIME OF DAY THE FRONT WILL BE MOVING THROUGH THE AREA. THE AMOUNT
OF PRECIPITATION EXPECTED WITH THIS SYSTEM IS LIMITED...BECAUSE THE
FRONT WILL BE MOVING FAIRLY QUICKLY THROUGH THE AREA. THE BEST CHANCE
TO SEE THE HEAVY RAIN WILL BE OUT AHEAD OF THE FRONT ON SATURDAY
NIGHT. NEAR RECORD TEMPERATURES ARE EXPECTED TOMORROW.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 306 AM EST SAT DEC 21 2013
THE SURFACE COLD FRONT WHICH BROUGHT THE RAIN AND WINDS DURING THE
SHORT TERM WILL HAVE MOVED SE OF THE REGION BY 0Z MONDAY.
HOWEVER...MODELS STILL SHOW A POOL OF MOISTURE/LIGHT PRECIP
REMAINING OVER THE FAR SE COUNTIES OF THE CWA. BASED ON LATEST
SOUNDINGS...THERE DOES SEEM TO BE A THIN LAYER OF DRY AIR NEAR THE
SURFACE WHICH COULD INHIBIT RAIN ACROSS THE REMAINDER OF THE REGION.
AS A RESULT...WAS RELUCTANT TO PUT IN ANYTHING OTHER THAN SLIGHT
CHANCE POPS FOR SEVERAL HOURS IN THESE LOCATIONS...BUT IF PRECIP
DOES OCCUR...IT WILL BE VERY LIGHT WITH LITTLE TO NO ACCUMULATION
EXPECTED. IN CONTRAST...SE KY COULD SEE SEVERAL HUNDREDTHS OF AN
INCH. THIS IS STILL RATHER UNIMPACTFUL. AN ABUNDANT AMOUNT OF DRY
AIR SEEMS TO BE PULLING IN ALOFT TOO...SO EXPECT ANY CLOUD COVER TO
BE CONFINED TO THE LOW LEVELS /LOW LEVEL CU/ INTO THE AFTERNOON HOURS
ACROSS THE REGION. THOUGH WINDS ALOFT WILL CONTINUE TO BE QUITE
STRONG...WITH HIGH PRESSURE COMING INTO PLAY...AND SIGNIFICANT DRYING
ALOFT...A DECENT NIGHT TIME INVERSION WILL FORM SUNDAY
NIGHT...PREVENTING THESE HIGHER WINDS FROM REACHING THE SURFACE. BY
MONDAY AFTERNOON...THE INVERSION WILL LIFT...AND WINDS WILL BE ABLE
TO MIX DOWN...BUT STILL SHOULD ONLY BE AROUND 15KTS OR LESS.
FOR MONDAY NIGHT...THE UPPER LEVEL TROUGH AXIS WILL PASS ACROSS
EASTERN KY. ONCE KY FINDS ITSELF ON THE BACK EDGE OF THIS
TROUGH...EXPECT AN ABUNDANT AMOUNT OF DRY AND COLD CANADIAN AIR TO
RUSH INTO THE REGION. FORECAST SOUNDINGS WILL COOL AND DRY
DRAMATICALLY. DAYTIME HIGHS TUESDAY WILL BE SIGNIFICANTLY
LOWER..BARELY REACHING FREEZING IN MOST LOCATIONS. TUESDAY NIGHT
WILL BE A SIMILAR STORY...WITH LOWS EXPECTED TO DROP DOWN INTO THE
UPPER TEENS TO NEAR 20.
MODELS ARE STILL SEEING A HIGH AMOUNT OF DISAGREEMENT IN THE LONG
TERM...BUT DO EXPECT SURFACE HIGH PRESSURE AND UPPER LEVEL RIDGING
TO LAST THROUGH WEDNESDAY NIGHT. THEN THERE IS A POTENTIAL FOR
ANOTHER SHORTWAVE TO MOVE INTO/NEAR THE OHIO VALLEY REGION DURING
THE DAY THURSDAY. WITH SUCH AN ABUNDANT AMOUNT OF DRY AIR IN
PLACE...DO NOT EXPECT ANY IMPACTS ON THURSDAY OTHER THAN HIGH
CLOUDS. HOWEVER...WINDS WILL HAVE SWITCHED TO A MORE SRLY
DIRECTION...ALLOWING FOR SOMEWHAT WARMER TEMPERATURES. A SHALLOW
LAYER OF MOISTURE SHOULD MAKE IT DOWN TO THE SURFACE BY FRIDAY
AFTERNOON/EVENING. BUT WILL AGREE WITH PREVIOUS FORECAST...THE
MOISTURE IS SO SHALLOW...WOULD NOT EXPECT MUCH MORE THAN A LIGHT
RAIN/DRIZZLE OR LIGHT SNOW EVENT. LITTLE TO NO ACCUMULATIONS ARE
EXPECTED AT THIS TIME. WITH CLOUD COVER IN PLACE...TEMPERATURES
SHOULD MODULATE AFTER THURSDAY...WITH HIGHS AND LOWS EXPECTED TO BE
CLOSER TO NORMAL FOR THIS TIME OF YEAR.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 106 AM EST SAT DEC 21 2013
CONDITIONS AT TAF ISSUANCE WERE A MIX OF MVFR AND LOW END VFR DUE TO
CEILINGS. THE MVFR WAS MOST PREVALENT IN THE WEST AND THE VFR MOST
PREVALENT IN THE EAST. THIS GENERAL SCENARIO IS EXPECTED TO PERSIST
OVERNIGHT...FOLLOWED BY PERHAPS A BIT OF IMPROVEMENT ON SATURDAY
MORNING. WITH MORE HUMID LOW LEVEL AIR BEING ADVECTED INTO THE REGION
FROM THE SW AND SOME LIMITED HEATING...WILL LOOK FOR A BKN LAYER OF
MVFR LEVEL STRATOCUMULUS TO DEVELOP OVER MUCH OF THE AREA ON SATURDAY
AFTERNOON...AND THEN DISSIPATE SATURDAY EVENING. SOME SHOWERS WILL
ALSO BE POSSIBLE ON SATURDAY...WITH THE GREATEST PROBABILITY IN THE
NW AROUND KIOB...AND THE LOWEST PROBABILITY IN THE SE NEAR THE VA
BORDER.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
LAKE WIND ADVISORY FROM 7 PM THIS EVENING TO 1 PM EST SUNDAY FOR
KYZ044-050>052-058>060-068-069-079-080-083>088-104-106>120.
&&
$$
UPDATE...HAL
SHORT TERM...JJ
LONG TERM...JMW
AVIATION...HAL
AREA FORECAST DISCUSSION
NWS JACKSON KY
119 AM EST SAT DEC 21 2013
.UPDATE...
ISSUED AT 119 AM EST SAT DEC 21 2013
BASED ON RECENT TRENDS...UPDATED TO LOWER WINDS SLIGHTLY OVERNIGHT AND TO
RAISE MIN TEMPS A BIT.
UPDATE ISSUED AT 1100 PM EST FRI DEC 20 2013
CURRENT CONDITIONS ACROSS THE AREA AS OF 04Z FEATURE SOME SCATTERED
SHOWERS MOVING NORTHEAST FROM TN INTO THE SOUTH CENTRAL AND SOUTHERN
I-75 CORRIDOR OF KENTUCKY. GENERALLY...THE NAM AND HRRR ARE AGREEING
ON ISOLATED TO SCATTERED SHOWERS SKIRTING THE WESTERN EXTEND OF THE
CWA...OR I-75 CORRIDOR THROUGH THE REST OF THE NIGHT. THE BEST LIFT
AND MOISTURE ARRIVES IN THE NORTHWEST IN THE 09Z TO 12Z TIME FRAME AND
IF THERE EVER IS A CHANCE FOR THUNDER TONIGHT...IT WILL OCCUR DURING
THIS PERIOD IN THE PREDAWN HOURS AND KEPT A SLIGHT CHANCE IN THE
FORECAST DUE TO THE LACK OF LIFT AND MOISTURE AT THIS TIME. HAVE
UPDATED AND SENT OUT A FRESH ZFP TO ACCOUNT FOR THIS ADJUSTMENT AND
LOADED CURRENT OBSERVATIONS AND SENT GRIDS TO NDFD.
UPDATE ISSUED AT 830 PM EST FRI DEC 20 2013
AS OF 0130Z SOME SHOWERS ARE BEGINNING TO DEVELOP AND MOVE INTO THE
AREA FROM THE SOUTH AS THE MOISTURE SURGE AND LIFT DEVELOPS AND MOVES
IN FROM THE SOUTHWEST. UPDATED THE GRIDS WITH THE MOST CURRENT OBS
AND HAVE SENT THEM TO NDFD. THE REST OF THE FORECAST IS ON TRACK.
UPDATE ISSUED AT 715 PM EST FRI DEC 20 2013
CURRENT CONDITIONS ACROSS THE AREA FEATURE A FEW STRAY SHOWERS
PASSING THROUGH EASTERN KENTUCKY BUT OTHERWISE ANY MEASURABLE PRECIP
LOOKS TO BE NONEXISTENT FOR AT LEAST THE NEXT COUPLE OF HOURS SO AT
THIS POINT...SLIGHT CHANCE SHOWERS LOOK TO BE THE WAY TO GO AND THEN
AS LIFT AND MOISTURE SURGE INCREASES TONIGHT...WILL INTRODUCE SOME
CHANCE AND LIKELY SHOWERS WITH AT LEAST SOME NOTICEABLE ISENTROPIC
LIFT JUST SKIRTING TO THE WEST OF THE I-75 CORRIDOR...WILL LEAVE
SLIGHT CHANCE THUNDERSTORMS JUST IN THE WESTERN ZONES AND ONLY
STARTING IN THE PREDAWN HOURS. HAVE ADJUSTED FOR PRECIP CHANCES
ARRIVING LATER SO A FRESH ZFP HAS BEEN ISSUED FOR THESE SLIGHT
CHANGES. OTHERWISE...HAVE LOADED IN THE LATEST OB AND SENT THE GRIDS
TO NDFD.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 359 PM EST FRI DEC 20 2013
ISOLATED TO SCATTERED SHOWERS HAVE BEEN MOVING ACROSS EASTERN
KENTUCKY TODAY. A FRONTAL SYSTEM EXTENDS FROM SOUTHERN MICHIGAN TO
NORTH CENTRAL TEXAS AND HAS MULTIPLE WAVES MOVING ALONG IT. THIS
WILL RESULT IN THE FRONT BOWING TO THE NORTH AHEAD OF THE LOW AND
THEN BOWING DOWN ON THE BACK SIDE OF THE LOW. THIS WILL CAUSE THE
FRONTS TO MOVE PRECIPITATION IN AND OUT OF THE AREA. THE COLD FRONT
WILL FINALLY MOVE THROUGH THE AREA ON SUNDAY WHEN THE UPPER TROUGH
MOVES TO THE WEST AND NORTH OF THE AREA. THE LATEST MODEL RUNS ARE
MOVING THE FRONT THROUGH THE AREA ON SUNDAY MORNING. THERE WILL BE A
STRONG LOW LEVEL JET OUT AHEAD OF THE FRONT. THE JET WILL BE MOVING
INTO THE AREA ON SATURDAY NIGHT. PUT OUT A LAKE WIND ADVISORY TO
COVER THE WIND GUSTS EXPECTED WITH THIS SYSTEM. IT IS POSSIBLE THAT
THIS MAY HAVE TO BE UPGRADED TO A WIND ADVISORY...HOWEVER SINCE IT
WILL BE NIGHT TIME...IT WILL BE HARDER TO MIX THE STRONGER GUSTS DOWN
TO THE SURFACE. THE UPPER ELEVATIONS WOULD BE MOST LIKELY TO SEE THE
STRONGEST GUSTS. THE SEVERE WEATHER THREAT IS ALSO MINIMIZED DUE TO
THE TIME OF DAY THE FRONT WILL BE MOVING THROUGH THE AREA. THE AMOUNT
OF PRECIPITATION EXPECTED WITH THIS SYSTEM IS LIMITED...BECAUSE THE
FRONT WILL BE MOVING FAIRLY QUICKLY THROUGH THE AREA. THE BEST CHANCE
TO SEE THE HEAVY RAIN WILL BE OUT AHEAD OF THE FRONT ON SATURDAY
NIGHT. NEAR RECORD TEMPERATURES ARE EXPECTED TOMORROW.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 409 PM EST FRI DEC 20 2013
THE EXTENDED WILL START OUT WITH A DEEP TROUGH ACROSS THE CENTRAL
CONUS. THIS TROUGH WILL DAMPEN AS IT BECOMES MORE CONSOLIDATED OVER
NEW ENGLAND BY TUESDAY. A SURFACE COLD FRONT WILL CONTINUE ITS SAG
TO THE SOUTHEAST SUNDAY NIGHT...WITH DEEPER MOISTURE EXITING EASTERN
KENTUCKY BY MONDAY MORNING. COLDER AIR WILL BE MOVING IN...WITH
TEMPERATURES LIKELY FALLING THROUGH THE DAY ON MONDAY. THERE
CONTINUES TO BE ENOUGH MOISTURE ADVERTISED FROM MONDAY THROUGH
MONDAY NIGHT TO JUSTIFY SOME SLIGHT CHANCE POPS...LIKELY IN THE FORM
OF FINE RAIN/DRIZZLE OR A BIT OF LIGHT SNOW OR FLURRIES.
DRY AND COLDER WEATHER WILL BE IN PLACE HEADING INTO MID-WEEK...WITH
LOWS DOWN INTO THE TEENS AND 20S TUESDAY AND WEDNESDAY MORNINGS.
ANOTHER TROUGH WILL TAKE AIM AT THE REGION BY THURSDAY...HOWEVER
THE MODEL DISAGREEMENT REMAINS. IN GENERAL...THERE HAS BEEN A DRIER
TREND...SO UNDERCUT THE GIVEN BLENDED MODEL GUIDANCE OUTPUT A BIT
AND KEPT SLIGHT CHANCE POPS IN. TEMPERATURE PROFILES SUPPORT
RAIN/SNOW...HOWEVER LITTLE IF ANY SNOW ACCUMULATION LOOKS TO OCCUR.
ANOTHER REINFORCING SHOT OF DRY AND COLDER HIGH PRESSURE WILL FOLLOW
FOR FRIDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 106 AM EST SAT DEC 21 2013
CONDITIONS AT TAF ISSUANCE WERE A MIX OF MVFR AND LOW END VFR DUE TO
CEILINGS. THE MVFR WAS MOST PREVALENT IN THE WEST AND THE VFR MOST
PREVALENT IN THE EAST. THIS GENERAL SCENARIO IS EXPECTED TO PERSIST
OVERNIGHT...FOLLOWED BY PERHAPS A BIT OF IMPROVEMENT ON SATURDAY
MORNING. WITH MORE HUMID LOW LEVEL AIR BEING ADVECTED INTO THE REGION
FROM THE SW AND SOME LIMITED HEATING...WILL LOOK FOR A BKN LAYER OF
MVFR LEVEL STRATOCUMULUS TO DEVELOP OVER MUCH OF THE AREA ON SATURDAY
AFTERNOON...AND THEN DISSIPATE SATURDAY EVENING. SOME SHOWERS WILL
ALSO BE POSSIBLE ON SATURDAY...WITH THE GREATEST PROBABILITY IN THE
NW AROUND KIOB...AND THE LOWEST PROBABILITY IN THE SE NEAR THE VA
BORDER.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
LAKE WIND ADVISORY FROM 7 PM THIS EVENING TO 1 PM EST SUNDAY FOR
KYZ044-050>052-058>060-068-069-079-080-083>088-104-106>120.
&&
$$
UPDATE...HAL
SHORT TERM...JJ
LONG TERM...GEOGERIAN
AVIATION...HAL
AREA FORECAST DISCUSSION
NWS JACKSON KY
106 AM EST SAT DEC 21 2013
.UPDATE...
ISSUED AT 1100 PM EST FRI DEC 20 2013
CURRENT CONDITIONS ACROSS THE AREA AS OF 04Z FEATURE SOME SCATTERED
SHOWERS MOVING NORTHEAST FROM TN INTO THE SOUTH CENTRAL AND SOUTHERN
I-75 CORRIDOR OF KENTUCKY. GENERALLY...THE NAM AND HRRR ARE AGREEING
ON ISOLATED TO SCATTERED SHOWERS SKIRTING THE WESTERN EXTEND OF THE
CWA...OR I-75 CORRIDOR THROUGH THE REST OF THE NIGHT. THE BEST LIFT
AND MOISTURE ARRIVES IN THE NORTHWEST IN THE 09Z TO 12Z TIME FRAME AND
IF THERE EVER IS A CHANCE FOR THUNDER TONIGHT...IT WILL OCCUR DURING
THIS PERIOD IN THE PREDAWN HOURS AND KEPT A SLIGHT CHANCE IN THE
FORECAST DUE TO THE LACK OF LIFT AND MOISTURE AT THIS TIME. HAVE
UPDATED AND SENT OUT A FRESH ZFP TO ACCOUNT FOR THIS ADJUSTMENT AND
LOADED CURRENT OBSERVATIONS AND SENT GRIDS TO NDFD.
UPDATE ISSUED AT 830 PM EST FRI DEC 20 2013
AS OF 0130Z SOME SHOWERS ARE BEGINNING TO DEVELOP AND MOVE INTO THE
AREA FROM THE SOUTH AS THE MOISTURE SURGE AND LIFT DEVELOPS AND MOVES
IN FROM THE SOUTHWEST. UPDATED THE GRIDS WITH THE MOST CURRENT OBS
AND HAVE SENT THEM TO NDFD. THE REST OF THE FORECAST IS ON TRACK.
UPDATE ISSUED AT 715 PM EST FRI DEC 20 2013
CURRENT CONDITIONS ACROSS THE AREA FEATURE A FEW STRAY SHOWERS
PASSING THROUGH EASTERN KENTUCKY BUT OTHERWISE ANY MEASURABLE PRECIP
LOOKS TO BE NONEXISTENT FOR AT LEAST THE NEXT COUPLE OF HOURS SO AT
THIS POINT...SLIGHT CHANCE SHOWERS LOOK TO BE THE WAY TO GO AND THEN
AS LIFT AND MOISTURE SURGE INCREASES TONIGHT...WILL INTRODUCE SOME
CHANCE AND LIKELY SHOWERS WITH AT LEAST SOME NOTICEABLE ISENTROPIC
LIFT JUST SKIRTING TO THE WEST OF THE I-75 CORRIDOR...WILL LEAVE
SLIGHT CHANCE THUNDERSTORMS JUST IN THE WESTERN ZONES AND ONLY
STARTING IN THE PREDAWN HOURS. HAVE ADJUSTED FOR PRECIP CHANCES
ARRIVING LATER SO A FRESH ZFP HAS BEEN ISSUED FOR THESE SLIGHT
CHANGES. OTHERWISE...HAVE LOADED IN THE LATEST OB AND SENT THE GRIDS
TO NDFD.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 359 PM EST FRI DEC 20 2013
ISOLATED TO SCATTERED SHOWERS HAVE BEEN MOVING ACROSS EASTERN
KENTUCKY TODAY. A FRONTAL SYSTEM EXTENDS FROM SOUTHERN MICHIGAN TO
NORTH CENTRAL TEXAS AND HAS MULTIPLE WAVES MOVING ALONG IT. THIS
WILL RESULT IN THE FRONT BOWING TO THE NORTH AHEAD OF THE LOW AND
THEN BOWING DOWN ON THE BACK SIDE OF THE LOW. THIS WILL CAUSE THE
FRONTS TO MOVE PRECIPITATION IN AND OUT OF THE AREA. THE COLD FRONT
WILL FINALLY MOVE THROUGH THE AREA ON SUNDAY WHEN THE UPPER TROUGH
MOVES TO THE WEST AND NORTH OF THE AREA. THE LATEST MODEL RUNS ARE
MOVING THE FRONT THROUGH THE AREA ON SUNDAY MORNING. THERE WILL BE A
STRONG LOW LEVEL JET OUT AHEAD OF THE FRONT. THE JET WILL BE MOVING
INTO THE AREA ON SATURDAY NIGHT. PUT OUT A LAKE WIND ADVISORY TO
COVER THE WIND GUSTS EXPECTED WITH THIS SYSTEM. IT IS POSSIBLE THAT
THIS MAY HAVE TO BE UPGRADED TO A WIND ADVISORY...HOWEVER SINCE IT
WILL BE NIGHT TIME...IT WILL BE HARDER TO MIX THE STRONGER GUSTS DOWN
TO THE SURFACE. THE UPPER ELEVATIONS WOULD BE MOST LIKELY TO SEE THE
STRONGEST GUSTS. THE SEVERE WEATHER THREAT IS ALSO MINIMIZED DUE TO
THE TIME OF DAY THE FRONT WILL BE MOVING THROUGH THE AREA. THE AMOUNT
OF PRECIPITATION EXPECTED WITH THIS SYSTEM IS LIMITED...BECAUSE THE
FRONT WILL BE MOVING FAIRLY QUICKLY THROUGH THE AREA. THE BEST CHANCE
TO SEE THE HEAVY RAIN WILL BE OUT AHEAD OF THE FRONT ON SATURDAY
NIGHT. NEAR RECORD TEMPERATURES ARE EXPECTED TOMORROW.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 409 PM EST FRI DEC 20 2013
THE EXTENDED WILL START OUT WITH A DEEP TROUGH ACROSS THE CENTRAL
CONUS. THIS TROUGH WILL DAMPEN AS IT BECOMES MORE CONSOLIDATED OVER
NEW ENGLAND BY TUESDAY. A SURFACE COLD FRONT WILL CONTINUE ITS SAG
TO THE SOUTHEAST SUNDAY NIGHT...WITH DEEPER MOISTURE EXITING EASTERN
KENTUCKY BY MONDAY MORNING. COLDER AIR WILL BE MOVING IN...WITH
TEMPERATURES LIKELY FALLING THROUGH THE DAY ON MONDAY. THERE
CONTINUES TO BE ENOUGH MOISTURE ADVERTISED FROM MONDAY THROUGH
MONDAY NIGHT TO JUSTIFY SOME SLIGHT CHANCE POPS...LIKELY IN THE FORM
OF FINE RAIN/DRIZZLE OR A BIT OF LIGHT SNOW OR FLURRIES.
DRY AND COLDER WEATHER WILL BE IN PLACE HEADING INTO MID-WEEK...WITH
LOWS DOWN INTO THE TEENS AND 20S TUESDAY AND WEDNESDAY MORNINGS.
ANOTHER TROUGH WILL TAKE AIM AT THE REGION BY THURSDAY...HOWEVER
THE MODEL DISAGREEMENT REMAINS. IN GENERAL...THERE HAS BEEN A DRIER
TREND...SO UNDERCUT THE GIVEN BLENDED MODEL GUIDANCE OUTPUT A BIT
AND KEPT SLIGHT CHANCE POPS IN. TEMPERATURE PROFILES SUPPORT
RAIN/SNOW...HOWEVER LITTLE IF ANY SNOW ACCUMULATION LOOKS TO OCCUR.
ANOTHER REINFORCING SHOT OF DRY AND COLDER HIGH PRESSURE WILL FOLLOW
FOR FRIDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 106 AM EST SAT DEC 21 2013
CONDITIONS AT TAF ISSUANCE WERE A MIX OF MVFR AND LOW END VFR DUE TO
CEILINGS. THE MVFR WAS MOST PREVALENT IN THE WEST AND THE VFR MOST
PREVALENT IN THE EAST. THIS GENERAL SCENARIO IS EXPECTED TO PERSIST
OVERNIGHT...FOLLOWED BY PERHAPS A BIT OF IMPROVEMENT ON SATURDAY
MORNING. WITH MORE HUMID LOW LEVEL AIR BEING ADVECTED INTO THE REGION
FROM THE SW AND SOME LIMITED HEATING...WILL LOOK FOR A BKN LAYER OF
MVFR LEVEL STRATOCUMULUS TO DEVELOP OVER MUCH OF THE AREA ON SATURDAY
AFTERNOON...AND THEN DISSIPATE SATURDAY EVENING. SOME SHOWERS WILL
ALSO BE POSSIBLE ON SATURDAY...WITH THE GREATEST PROBABILITY IN THE
NW AROUND KIOB...AND THE LOWEST PROBABILITY IN THE SE NEAR THE VA
BORDER.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
LAKE WIND ADVISORY FROM 7 PM THIS EVENING TO 1 PM EST SUNDAY FOR
KYZ044-050>052-058>060-068-069-079-080-083>088-104-106>120.
&&
$$
UPDATE...SHALLENBERGER
SHORT TERM...JJ
LONG TERM...GEOGERIAN
AVIATION...HAL
AREA FORECAST DISCUSSION
NWS PADUCAH KY
1158 PM CST Fri Dec 20 2013
.UPDATE...
ISSUED AT 1158 PM CST FRI DEC 20 2013
The AVIATION section has been updated for the 06Z TAF issuance.
UPDATE ISSUED AT 1016 PM CST FRI DEC 20 2013
Latest forecast update accounts for colder temperatures following
cold front progressing southeast across the area. As of 04Z, the
front stretched from roughly the Wabash River Valley to just east
of Harrisburg, Illinois to just northwest of Cape Girardeau and
Poplar Bluff, Missouri.
Area Doppler radar mosaic depicts an initial round of showers and
a few thunderstorms over mainly southern Illinois. The next round
of activity was already lifting north across northeast Arkansas
and western Tennessee and will spread across the region overnight.
Utilized a blend of the NAM12, RAP13, and current forecast.
Overall, going forecast appears to remain on track through
Saturday morning. However, two potential scenarios could shift the
forecast in one direction or another.
(1.) The latter part of the RAP13 is much more aggressive
with the southeastward progress of the cold frontal boundary into
western Kentucky by Saturday afternoon. This can easily be
supported by precipitation loading and its cooling effect, which
may effectively push the frontal boundary further south than
currently forecast. If this were to pan out, the potential for
severe weather would essentially focus across the southern
Pennyrile region and further south.
(2.) Meanwhile, the NAM12 is much more insistent that the frontal
boundary will hang up across far southeast Missouri, southeast
Illinois, and even far southern Indiana. If this pans out, then
the severe potential would be much more concerning by Saturday
afternoon and evening.
While the current forecast embraces neither of these extremes,
they are nonetheless worth keeping in mind as we proceed through
what promises to be a heavy rain event at the very least.
&&
.SHORT TERM...(This Evening through Sunday)
ISSUED AT 238 PM CST FRI DEC 20 2013
Flood Watch will continue as is tonight through Saturday night.
Still looking at 2-4+ inches area wide, slightly higher amounts
to 5 inches possible near and just NW of the Ohio River. Front
will enter the area tonight and stall near the Ohio River. Rain
and storms forecast to increase tonight especially after midnight,
continuing through Saturday.
Could see a few strong to severe storms Saturday late day and
evening as wind fields increase substantially with some surface
based instability along and south of the boundary, especially
across west Kentucky. Isolated damaging wind gusts and a brief
short lived tornado or two cannot be ruled out. The activity
should quickly push to the east after midnight Saturday as we
dry slot. Mid level drying will be pronounced, but low level
moisture will linger with SW flow aloft. May be some drizzle into
Sunday but that`s about it, as temperatures fall through the day.
In terms of temps, dew points and winds with the front coming into
the area tonight and Saturday, used a blend of RAP 13km data and
short term 3 hourly GFS/NAM data.
.LONG TERM...(Sunday Night through Friday)
ISSUED AT 238 PM CST FRI DEC 20 2013
In the wake of the weekend storm...colder and drier air will arrive
for early next week. Model soundings depict some lingering moisture
Sunday night until the passage of the 850 mb trough axis. This could
translate into some flurries or drizzle...but no measurable precip
is indicated in the 12z gfs/nam/ecmwf model qpf. By Monday
night...mainly clear skies are expected.
Monday night...the combination of clear skies and decreasing winds
should allow temps to radiate nicely. Will lower Monday night
lows closer to gfs and ecmwf mos...both of which range from 10 to 15
degrees across most of the area.
Tuesday will be another cold day...but there is about a 10 degree
difference between ecmwf and gfs mos highs. The 00z ecmwf is more
progressive with the eastward motion of the thermal trough...while
the 12z gfs lingers the cold air through the day. Will split the
difference between them...which yields highs in the upper 20s to
lower 30s despite sunny skies.
The models depict a 500 mb longwave trough axis setting up over the
Mississippi Valley Christmas Day into Thursday. Shortwaves rotating
through the trough will bring at least some cloudiness...if not
measurable light precip. Model soundings have trended drier during
this time period...and the 12z gfs and gfs ensemble mean show zero
qpf. The 12z ecmwf indicates some patchy light precip. Will follow
the model trends and lower pops into the slight chance category for
Christmas night and Thursday. Precip type would be mainly snow until
boundary layer temps become marginal for snow Thursday
afternoon.
In the wake of the departing longwave trough...another shot of cold
air is expected for Friday. As would be expected seven days
out...there is fair to poor agreement on how cold it will get.
Forecast will represent a blend of gfs/ecmwf temps.
&&
.AVIATION...
ISSUED AT 1158 PM CST FRI DEC 20 2013
Low confidence forecast, with considerable uncertainty in the
frontal position/movement through the period. It does appear that
IFR conditions in heavy rain will prevail at all sites for most,
if not all of the TAF period. Lower conditions will be possible at
times, especially near the front, which unfortunately will be
draped across the terminals for much of the period. The potential
exists for some very strong and gusty south/southwest winds in the
warm sector Saturday afternoon and evening. This would be most
likely at KOWB, but cannot be ruled out at KPAH and KEVV.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...FLOOD WATCH through late Saturday night FOR ILZ075>078-080>094.
MO...FLOOD WATCH through late Saturday night FOR MOZ076-086-087-100-
107>112-114.
IN...FLOOD WATCH through late Saturday night FOR INZ081-082-085>088.
KY...FLOOD WATCH through late Saturday night FOR KYZ001>022.
&&
$$
UPDATE...DRS
AVIATION...DRS
AREA FORECAST DISCUSSION
NWS PADUCAH KY
1016 PM CST Fri Dec 20 2013
.UPDATE...
ISSUED AT 1016 PM CST FRI DEC 20 2013
Latest forecast update accounts for colder temperatures following
cold front progressing southeast across the area. As of 04Z, the
front stretched from roughly the Wabash River Valley to just east
of Harrisburg, Illinois to just northwest of Cape Girardeau and
Poplar Bluff, Missouri.
Area Doppler radar mosaic depicts an initial round of showers and
a few thunderstorms over mainly southern Illinois. The next round
of activity was already lifting north across northeast Arkansas
and western Tennessee and will spread across the region overnight.
Utilized a blend of the NAM12, RAP13, and current forecast.
Overall, going forecast appears to remain on track through
Saturday morning. However, two potential scenarios could shift the
forecast in one direction or another.
(1.) The latter part of the RAP13 is much more aggressive
with the southeastward progress of the cold frontal boundary into
western Kentucky by Saturday afternoon. This can easily be
supported by precipitation loading and its cooling effect, which
may effectively push the frontal boundary further south than
currently forecast. If this were to pan out, the potential for
severe weather would essentially focus across the southern
Pennyrile region and further south.
(2.) Meanwhile, the NAM12 is much more insistent that the frontal
boundary will hang up across far southeast Missouri, southeast
Illinois, and even far southern Indiana. If this pans out, then
the severe potential would be much more concerning by Saturday
afternoon and evening.
While the current forecast embraces neither of these extremes,
they are nonetheless worth keeping in mind as we proceed through
what promises to be a heavy rain event at the very least.
&&
.SHORT TERM...(This Evening through Sunday)
ISSUED AT 238 PM CST FRI DEC 20 2013
Flood Watch will continue as is tonight through Saturday night.
Still looking at 2-4+ inches area wide, slightly higher amounts
to 5 inches possible near and just NW of the Ohio River. Front
will enter the area tonight and stall near the Ohio River. Rain
and storms forecast to increase tonight especially after midnight,
continuing through Saturday.
Could see a few strong to severe storms Saturday late day and
evening as wind fields increase substantially with some surface
based instability along and south of the boundary, especially
across west Kentucky. Isolated damaging wind gusts and a brief
short lived tornado or two cannot be ruled out. The activity
should quickly push to the east after midnight Saturday as we
dry slot. Mid level drying will be pronounced, but low level
moisture will linger with SW flow aloft. May be some drizzle into
Sunday but that`s about it, as temperatures fall through the day.
In terms of temps, dew points and winds with the front coming into
the area tonight and Saturday, used a blend of RAP 13km data and
short term 3 hourly GFS/NAM data.
.LONG TERM...(Sunday Night through Friday)
ISSUED AT 238 PM CST FRI DEC 20 2013
In the wake of the weekend storm...colder and drier air will arrive
for early next week. Model soundings depict some lingering moisture
Sunday night until the passage of the 850 mb trough axis. This could
translate into some flurries or drizzle...but no measurable precip
is indicated in the 12z gfs/nam/ecmwf model qpf. By Monday
night...mainly clear skies are expected.
Monday night...the combination of clear skies and decreasing winds
should allow temps to radiate nicely. Will lower Monday night
lows closer to gfs and ecmwf mos...both of which range from 10 to 15
degrees across most of the area.
Tuesday will be another cold day...but there is about a 10 degree
difference between ecmwf and gfs mos highs. The 00z ecmwf is more
progressive with the eastward motion of the thermal trough...while
the 12z gfs lingers the cold air through the day. Will split the
difference between them...which yields highs in the upper 20s to
lower 30s despite sunny skies.
The models depict a 500 mb longwave trough axis setting up over the
Mississippi Valley Christmas Day into Thursday. Shortwaves rotating
through the trough will bring at least some cloudiness...if not
measurable light precip. Model soundings have trended drier during
this time period...and the 12z gfs and gfs ensemble mean show zero
qpf. The 12z ecmwf indicates some patchy light precip. Will follow
the model trends and lower pops into the slight chance category for
Christmas night and Thursday. Precip type would be mainly snow until
boundary layer temps become marginal for snow Thursday
afternoon.
In the wake of the departing longwave trough...another shot of cold
air is expected for Friday. As would be expected seven days
out...there is fair to poor agreement on how cold it will get.
Forecast will represent a blend of gfs/ecmwf temps.
&&
.AVIATION...
ISSUED AT 559 PM CST FRI DEC 20 2013
Made a few modifications to the existing TAFs. MVFR ceilings are
bouncing in and out across the area early this evening, so threw
in a TEMPO to handle that situation.
The front is just now entering the area and will pass KCGI this
evening. It will settle over KPAH and KEVV late tonight and become
stationary well into Saturday morning. Current thinking is that it
will stay southeast of KCGI and not pass KOWB through the end of this
TAF period. Added a couple of groups to handle the cha cha cha
expected at KPAH and KEVV late tonight through late Saturday
morning. Could see some strong south winds with gusts over 20kts
Saturday afternoon, except at KCGI.
Continued with the showers and VCTS through the day Saturday, with
gradually lowering ceilings through the period. IFR or lower
conditions are expected for much of the day.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...FLOOD WATCH through late Saturday night FOR ILZ075>078-080>094.
MO...FLOOD WATCH through late Saturday night FOR MOZ076-086-087-100-
107>112-114.
IN...FLOOD WATCH through late Saturday night FOR INZ081-082-085>088.
KY...FLOOD WATCH through late Saturday night FOR KYZ001>022.
&&
$$
UPDATE...RJP
AVIATION...DRS
AREA FORECAST DISCUSSION
NWS CARIBOU ME
953 PM EST SUN DEC 22 2013
.SYNOPSIS...
WEAK LOW PRESSURE WILL REMAIN OVER THE GULF OF MAINE THROUGH
MONDAY. COLD HIGH PRESSURE WILL THEN MOVE IN TUESDAY AND
WEDNESDAY.
&&
.NEAR TERM /THROUGH MONDAY/...
952 PM UPDATE...THERE CONTINUES TO BE A BREAK IN THE ACTION
ACROSS DOWNEAST AREAS LATE THIS EVENING WITH FREEZING DRIZZLE
FALLING IN SPOTS...BUT NOT THE HEAVIER FREEZING RAIN THAT IMPACTED
THE AREA DURING THE DAY SUNDAY. THERE IS NOT MUCH CHANGE ACROSS
NORTHERN MAINE EITHER FROM EARLIER THIS EVENING. THERE CONTINUES
TO BE A BIT MORE COVERAGE AND INTENSITY TO THE PRECIPITATION FROM
ABOUT LINCOLN NORTH. THE PRECIPITATION IS FALLING IN MOST AREAS
AS SNOW...WITH A MIX OF SNOW AND SLEET ACROSS CENTRAL MAINE.
THE HRRR CONTINUES TO HAVE A PRETTY GOOD HANDLE ON THE AREAS THAT
ARE GETTING PRECIPITATION VERSUS THE AREAS THAT ARE GETTING
FREEZING DRIZZLE OR NOTHING AT ALL. THERE IS A VERY STRONG FRONTAL
BOUNDARY THAT EXTENDS ACROSS CENTRAL NY STATE INTO CENTRAL
MASSACHUSETTS WITH TEMPERATURES NEARLY 30 DEGREES WARMER TO THE
SOUTH OF THIS BOUNDARY. THE FRONT WILL REMAIN WELL SOUTH OF OUR
AREA TONIGHT....HOWEVER...TEMPS RIGHT ALONG THE IMMEDIATE COAST
MAY SLOWLY RISE TO AROUND OR JUST ABOVE FREEZING BY MORNING.
PRECIPITATION THAT IS BREAKING OUT DOWN ACROSS VIRGINIA LATE
THIS EVENING WILL STREAM TO THE NORTHEAST OVERNIGHT AND SHOULD
OVERSPREAD MUCH OF DOWNEAST MAINE BY AROUND 12Z MON MORNING. NO
MAJOR CHANGES TO THE ONGOING FORECAST WITH JUST A FEW TWEAKS.
THE CONCERN REMAINS THAT WHEN THE STEADY PRECIPITATION MOVES BACK
ACROSS DOWNEAST AREAS TOMORROW THAT TEMPERATURES RIGHT ALONG THE
COAST WILL BE ABOVE FREEZING AND ICING MAY NOT END UP BEING A
MAJOR CONCERN FOR THE IMMEDIATE COASTAL COMMUNITIES. BANGOR AND
INLAND AREAS STILL LOOK LIKELY TO SEE ANOTHER ROUND OF FREEZING
RAIN TOMORROW. HAVE ADDRESSED THIS IN FREEZING RAIN ADVISORY BY
ADVERTISING THE GREATEST CONCERN FOR ICING BEING INLAND.
PREVIOUS DISCUSSION... HANCOCK AND WASHINGTON COUNTY HAVE GOTTEN
HIT THE HARDEST WITH THE ICE STORM WITH ABOUT ONE HALF INCH ICE
ACCRETION. SNOW ACCUMULATIONS OVER THE NORTH HAVE BEEN 4 TO 10
INCHES. IN BETWEEN, IT HAS BEEN A MIX OF SNOW, SLEET, AND FREEZING
RAIN WITH GENERALLY SLEET AMOUNTING TO THE MAJORITY OF THE
ACCUMULATIONS. SEE OUR PUBLIC INFORMATION STATEMENT FOR MORE
TOTALS.
THROUGH TONIGHT, BOTTOM LINE IS THAT PRECIPITATION WILL BE QUITE
LIGHT, UNTIL ANOTHER ROUND OF PRECIP MOVES IN DOWNEAST ON
MONDAY. A DEFINITE BREAK BETWEEN SYSTEMS, AND HAVE OPTED TO DROP
ALL THE WARNINGS AND REPLACE IT WITH A WINTER WEATHER ADVISORIES
AND FREEZING RAIN ADVISORIES, EFFECTIVE NOW THROUGH LATE MONDAY,
FOR ALL BUT THE EXTREME NORTH.
LIGHT SLEET, FREEZING DRIZZLE, AND SNIZZLE HAS MADE IT AS FAR
NORTH AS ABOUT CARIBOU THIS EVENING BUT WILL RETREAT SOUTH A BIT
TONIGHT. GENERALLY, FROM MARS HILL NORTH LOOK FOR AN INCH OR TWO
OF MOSTLY SNOW TONIGHT, WITH JUST VERY LIGHT INTERMITTENT
PRECIPITATION SOUTH OF MARS HILL FALLING AS FREEZING DRIZZLE OR
SLEET.
ON MONDAY DURING THE DAY, HOWEVER, HEAVIER PRECIP MOVES BACK IN
MAINLY FROM I-95 SOUTH/EAST. FEEL THAT MOST AREAS EXCEPT PERHAPS
THE VERY IMMEDIATE COAST WILL STAY JUST BELOW FREEZING, WITH
FREEZING RAIN BEING THE PREDOMINANT PRECIP TYPE FOR DOWNEAST WITH
UP TO ONE QUARTER INCH ADDITIONAL ICE ACCRETION. INTO CENTRAL
AREAS, THE PRECIP WILL BE LIGHTER AND WE ARE LOOKING FOR A MIX OF
SNOW, SLEET, AND FREEZING RAIN WITH UP TO ONE TENTH INCH ICE.
ADVISORIES TO COVER THIS EVENT RUN THROUGH THE END OF THE DAY
MONDAY. FELT MOST MODEL GUIDANCE WAS TOO WARM FOR SURFACE TEMPS
FOR MONDAY AND UNDERCUT THEM BY SEVERAL DEGREES.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
A WEAK COASTAL SURFACE LOW PRESSURE SYSTEM WILL BE MOVING INTO THE
CANADIAN MARITIMES MONDAY EVENING AND BRING TO AN END A PROLONGED
PERIOD OF MIXED PRECIPITATION FOR DOWNEAST MAINE. WILL SEE LIGHT
SNOW OR SNOW SHOWERS ACROSS NORTHERN MAINE INTO TUESDAY WITH AN
INVERTED TROUGH. NORTHWEST WINDS WILL PICK UP ON TUESDAY BEHIND
THIS SYSTEM AND MAY CAUSE SOME ISSUES FOR LOCATIONS WITH ICE ON
TREES AND STRUCTURES. COLD CANADIAN HIGH PRESSURE BUILDS INTO
MAINE FOR CHRISTMAS DAY WITH TEMPERATURES AROUND 15 DEGREES BELOW
CLIMATOLOGY.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
THE 12Z ECMWF IS FAR MORE ACTIVE FOR NORTHERN NEW ENGLAND THROUGH
NEXT WEEKEND COMPARED THE 12Z GFS. THE ECWMF AMPLIFIES A CLIPPER
SYSTEM THURSDAY NIGHT AND EARLY FRIDAY IN A SIMILAR MANNER TO A
RECENT STORM ON DECEMBER 17-18. THIS MODEL LATER BRINGS ANOTHER
AREA OF SURFACE LOW PRESSURE ON SUNDAY. THE GFS IS NOTICEABLY
WEAKER WITH BOTH SYSTEMS. LOADED A BLEND OF THESE MODELS WITH AN
EMPHASIS ON THURSDAY NIGHT/FRIDAY AND SUNDAY.
&&
.AVIATION /02Z MONDAY THROUGH FRIDAY/...
NEAR TERM: MOSTLY VLIFR TO IFR AT THE TERMINALS THROUGH MONDAY.
PRECIPITATION WILL MAINLY BE SNOW OR A MIX OF SNOW AND SLEET NORTH
OF KPQI AND FREEZING DRIZZLE AT KBGR AND KBHB. STEADIER FREEZING
RAIN WILL DEVELOP AT KBGR MONDAY WITH FREEZING RAIN LIKELY
CHANGING TO RAIN AT KBHB.
SHORT TERM: IFR CIGS AND VSBYS WILL BE POSSIBLE DUE TO SNOW AND/OR
MIXED PRECIPITATION MONDAY NIGHT WITH A DEPARTING WEAK SURFACE LOW
PRESSURE SYSTEM. LIFR/IFR CIGS AND VSBYS WILL BE POSSIBLE THURSDAY
NIGHT AND FRIDAY DUE TO SNOW AND FOG.
&&
.MARINE...
NEAR TERM:
SMALL CRAFT CONDITIONS THROUGH ABOUT MIDDAY MONDAY THEN IMPROVING.
SEAS THIS EVENING AS OF 9 PM ARE RUNNING AROUND 8 FEET AT THE
EASTERN MAINE SHELF WITH A NORTH TO NORTHEAST WIND OF 15 TO 20 KNOTS.
SHORT TERM: NO HEADLINES ARE EXPECTED THROUGH THURSDAY. AN SCA OR GALE
WATCH MAY BE NEEDED THURSDAY NIGHT AND FRIDAY WITH AN AMPLIFYING
CLIPPER SYSTEM.
&&
.EQUIPMENT...
SWITCHED THE RADAR TO CLEAR AIR MODE TO BETTER PICK UP THE
LIGHTER PRECIPITATION FALLING ACROSS THE AREA.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...FREEZING RAIN ADVISORY UNTIL 6 PM EST MONDAY FOR MEZ011-
015>017-029-030-032.
WINTER WEATHER ADVISORY UNTIL 4 PM EST MONDAY FOR MEZ003>006-
010-031.
MARINE...SMALL CRAFT ADVISORY UNTIL NOON EST MONDAY FOR ANZ050>052.
&&
$$
NEAR TERM...CB/FOISY
SHORT TERM...OKULSKI
LONG TERM...OKULSKI
AVIATION...CB/FOISY/OKULSKI
MARINE...CB/FOISY/OKULSKI
EQUIPMENT...CB
AREA FORECAST DISCUSSION
NWS CARIBOU ME
625 PM EST SUN DEC 22 2013
.SYNOPSIS...
WEAK LOW PRESSURE WILL REMAIN OVER THE GULF OF MAINE THROUGH
MONDAY. COLD HIGH PRESSURE WILL THEN MOVE IN TUESDAY AND
WEDNESDAY.
&&
.NEAR TERM /THROUGH MONDAY/...
625 PM UPDATE...THERE IS DEFINITELY A BREAK IN THE ACTION THIS
EVENING ACROSS DOWNEAST AREAS WHERE THERE IS NOT MORE THAN SOME
SPOTTY FREEZING DRIZZLE. A BIT MORE COVERAGE AND INTENSITY TO THE
PRECIPITATION ACROSS NORTHERN MAINE...WITH THE PRECIPITATION
FALLING IN MOST AREAS AS EITHER SNOW OR A MIX OF SNOW AND SLEET
WITH A BIT OF FREEZING RAIN OBSERVED ABOUT AS FAR NORTH AS THE
HOULTON/MARS HILL AREAS. THE LATEST HRRR HAS A PRETTY GOOD HANDLE
ON THE AREAS THAT ARE GETTING PRECIPITATION VERSUS THE AREAS THAT
ARE GETTING FREEZING DRIZZLE OR NOTHING AT ALL. THERE IS A VERY
STRONG FRONTAL BOUNDARY THAT EXTENDS ACROSS CENTRAL NY STATE INTO
CENTRAL MASSACHUSETTS WITH TEMPERATURES NEARLY 30 DEGREES WARMER
TO THE SOUTH OF THIS BOUNDARY. THE FRONT WILL REMAIN WELL SOUTH OF
OUR AREA TONIGHT....HOWEVER...TEMPS RIGHT ALONG THE IMMEDIATE
COAST MAY SLOWLY RISE TO AROUND OR JUST ABOVE FREEZING BY MORNING.
NO MAJOR CHANGES TO THE ONGOING FORECAST WITH JUST A FEW TWEAKS.
ONE CONCERN IS THAT WHEN THE STEADY PRECIPITATION MOVES BACK
ACROSS DOWNEAST AREAS TOMORROW THAT TEMPERATURES RIGHT ALONG THE
COAST WILL BE ABOVE FREEZING AND ICING MAY NOT END UP BEING A
MAJOR CONCERN FOR THE IMMEDIATE COASTAL COMMUNITIES. BANGOR AND
INLAND AREAS STILL LOOK LIKELY TO SEE ANOTHER ROUND OF FREEZING
RAIN TOMORROW.
PREVIOUS DISCUSSION... HANCOCK AND WASHINGTON COUNTY HAVE GOTTEN
HIT THE HARDEST WITH THE ICE STORM WITH ABOUT ONE HALF INCH ICE
ACCRETION. SNOW ACCUMULATIONS OVER THE NORTH HAVE BEEN 4 TO 10
INCHES. IN BETWEEN, IT HAS BEEN A MIX OF SNOW, SLEET, AND FREEZING
RAIN WITH GENERALLY SLEET AMOUNTING TO THE MAJORITY OF THE
ACCUMULATIONS. SEE OUR PUBLIC INFORMATION STATEMENT FOR MORE
TOTALS.
THROUGH TONIGHT, BOTTOM LINE IS THAT PRECIPITATION WILL BE QUITE
LIGHT, UNTIL ANOTHER ROUND OF PRECIP MOVES IN DOWNEAST ON
MONDAY. A DEFINITE BREAK BETWEEN SYSTEMS, AND HAVE OPTED TO DROP
ALL THE WARNINGS AND REPLACE IT WITH A WINTER WEATHER ADVISORIES
AND FREEZING RAIN ADVISORIES, EFFECTIVE NOW THROUGH LATE MONDAY,
FOR ALL BUT THE EXTREME NORTH.
LIGHT SLEET, FREEZING DRIZZLE, AND SNIZZLE HAS MADE IT AS FAR
NORTH AS ABOUT CARIBOU THIS EVENING BUT WILL RETREAT SOUTH A BIT
TONIGHT. GENERALLY, FROM MARS HILL NORTH LOOK FOR AN INCH OR TWO
OF MOSTLY SNOW TONIGHT, WITH JUST VERY LIGHT INTERMITTENT
PRECIPITATION SOUTH OF MARS HILL FALLING AS FREEZING DRIZZLE OR
SLEET.
ON MONDAY DURING THE DAY, HOWEVER, HEAVIER PRECIP MOVES BACK IN
MAINLY FROM I-95 SOUTH/EAST. FEEL THAT MOST AREAS EXCEPT PERHAPS
THE VERY IMMEDIATE COAST WILL STAY JUST BELOW FREEZING, WITH
FREEZING RAIN BEING THE PREDOMINANT PRECIP TYPE FOR DOWNEAST WITH
UP TO ONE QUARTER INCH ADDITIONAL ICE ACCRETION. INTO CENTRAL
AREAS, THE PRECIP WILL BE LIGHTER AND WE ARE LOOKING FOR A MIX OF
SNOW, SLEET, AND FREEZING RAIN WITH UP TO ONE TENTH INCH ICE.
ADVISORIES TO COVER THIS EVENT RUN THROUGH THE END OF THE DAY
MONDAY. FELT MOST MODEL GUIDANCE WAS TOO WARM FOR SURFACE TEMPS
FOR MONDAY AND UNDERCUT THEM BY SEVERAL DEGREES.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
A WEAK COASTAL SURFACE LOW PRESSURE SYSTEM WILL BE MOVING INTO THE
CANADIAN MARITIMES MONDAY EVENING AND BRING TO AN END A PROLONGED
PERIOD OF MIXED PRECIPITATION FOR DOWNEAST MAINE. WILL SEE LIGHT
SNOW OR SNOW SHOWERS ACROSS NORTHERN MAINE INTO TUESDAY WITH AN
INVERTED TROUGH. NORTHWEST WINDS WILL PICK UP ON TUESDAY BEHIND
THIS SYSTEM AND MAY CAUSE SOME ISSUES FOR LOCATIONS WITH ICE ON
TREES AND STRUCTURES. COLD CANADIAN HIGH PRESSURE BUILDS INTO
MAINE FOR CHRISTMAS DAY WITH TEMPERATURES AROUND 15 DEGREES BELOW
CLIMATOLOGY.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
THE 12Z ECMWF IS FAR MORE ACTIVE FOR NORTHERN NEW ENGLAND THROUGH
NEXT WEEKEND COMPARED THE 12Z GFS. THE ECWMF AMPLIFIES A CLIPPER
SYSTEM THURSDAY NIGHT AND EARLY FRIDAY IN A SIMILAR MANNER TO A
RECENT STORM ON DECEMBER 17-18. THIS MODEL LATER BRINGS ANOTHER
AREA OF SURFACE LOW PRESSURE ON SUNDAY. THE GFS IS NOTICEABLY
WEAKER WITH BOTH SYSTEMS. LOADED A BLEND OF THESE MODELS WITH AN
EMPHASIS ON THURSDAY NIGHT/FRIDAY AND SUNDAY.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
NEAR TERM: VLIFR TO IFR AT THE TERMINALS THROUGH MONDAY.
PRECIPITATION WILL MAINLY BE SNOW OR A MIX OF SNOW AND SLEET NORTH
OF KPQI AND FREEZING DRIZZLE AT KBGR AND KBHB. STEADIER FREEZING
RAIN WILL DEVELOP AT KBGR MONDAY WITH FREEZING RAIN LIKELY
CHANGING TO RAIN AT KBHB.
SHORT TERM: IFR CIGS AND VSBYS WILL BE POSSIBLE DUE TO SNOW AND/OR
MIXED PRECIPITATION MONDAY NIGHT WITH A DEPARTING WEAK SURFACE LOW
PRESSURE SYSTEM. LIFR/IFR CIGS AND VSBYS WILL BE POSSIBLE THURSDAY
NIGHT AND FRIDAY DUE TO SNOW AND FOG.
&&
.MARINE...
NEAR TERM:
SMALL CRAFT CONDITIONS THROUGH ABOUT MIDDAY MONDAY THEN IMPROVING.
SEAS THIS EVENING ARE RUNNING AROUND 8 FEET AT THE EASTERN MAINE
SHELF WITH A NORTH TO NORTHEAST WIND OF AROUND 20 KTS WITH GUSTS TO
25 TO 30 KTS.
SHORT TERM: NO HEADLINES ARE EXPECTED THROUGH THURSDAY. AN SCA OR GALE
WATCH MAY BE NEEDED THURSDAY NIGHT AND FRIDAY WITH AN AMPLIFYING
CLIPPER SYSTEM.
&&
.EQUIPMENT...SWITCHED THE RADAR FROM VCP 21 TO 31 EARLIER THIS
EVENING TO BETTER PICK UP THE LIGHTER PRECIPITATION FALLING ACROSS
THE AREA.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...FREEZING RAIN ADVISORY UNTIL 6 PM EST MONDAY FOR MEZ011-
015>017-029-030-032.
WINTER WEATHER ADVISORY UNTIL 4 PM EST MONDAY FOR MEZ003>006-
010-031.
MARINE...SMALL CRAFT ADVISORY UNTIL NOON EST MONDAY FOR ANZ050>052.
&&
$$
NEAR TERM...CB/FOISY
SHORT TERM...OKULSKI
LONG TERM...OKULSKI
AVIATION...CB/FOISY/OKULSKI
MARINE...CB/FOISY/OKULSKI
EQUIPMENT...CB
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
352 PM EST SAT DEC 21 2013
.SYNOPSIS...
A STRONG COLD FRONT ACCOMPANIED BY GUSTY WINDS PASSES SUNDAY.
AREA RIVERS WILL BE ON THE RISE THROUGH MONDAY. AN UPPER LEVEL
DISTURBANCE BRINGS SNOW SHOWERS MONDAY NIGHT INTO TUESDAY. MUCH
CALMER WEATHER THE BALANCE OF THE HOLIDAY WEEK WITH BELOW NORMAL
TEMPERATURES.
&&
.NEAR TERM /THROUGH SUNDAY/...
SOUTHERLY FLOW CONTINUES TO INCREASE AHEAD OF DEEPENING SFC CYCLONE
WHICH IS EVIDENT BY VIEWING REGIONAL RADAR MOSAIC AS PLUME OF RAIN
CONTINUES TO SHIFT NNE. DRY WEATHER HAS ALREADY REACHED NRN WV AND
WRN MD AND WILL CONTINUE TO OVERSPREAD MUCH OF THE CWA THIS
EVENING. PARTIAL CLEARING OVER THE NORTHERN WV MOUNTAINS HAS
ALLOWED TEMPS TO SOAR INTO THE MID 70S. THIS AIR WILL MAKE IT TO
THE MASON DIXON LINE...WHILE 60S SHALL ENCOMPASS WRN PA AND THE
NRN WV PANHANDLE. TEMPS WILL NOT FALL MUCH TONIGHT AS BOUNDARY
LAYER REMAINS WELL MIXED.
COLD FRONT CROSSES SUNDAY MORNING INTO EARLY AFTERNOON. BAND OF
MODERATE TO HEAVY SHOWERS WILL BE OUT AHEAD OF IT. THERMODYNAMIC
PARAMETERS STILL ARE NOT OVERLY IMPRESSIVE DUE TO THE TIME OF DAY
IT CROSSES. UPPER LEVEL DYNAMICS DO NOT WOW ME EITHER AS STRONG
AGEOSTROPHIC FORCING RESULTING FROM JET COUPLING IS NOT PRESENT.
CONTINUED TO OMIT THUNDER FROM FCST...DESPITE SPC BRINGING SLIGHT
RISK TO NRN WV PANHANDLE. GUSTY WINDS UPWARDS OF 40 MPH MAY OCCUR BASED
ON MOMENTUM TRANSFER. THIS COULD KNOCK AROUND OUTDOOR CHRISTMAS
DECORATIONS. HRRR AGREES WITH THIS BASED ON 10M WIND GUST FIELD.
HEAVY RAIN REMAINS A CONCERN ACROSS THE FLOOD WATCH AREA. AT THIS
TIME...ADDITIONAL AMOUNTS UPWARDS OF AN INCH COULD LEAD TO
FLOODING. THE PERIOD OF DRY WEATHER THIS EVENING HELPS OFFSET A
WIDESPREAD THREAT OF HIGH WATER IN THE WATCH AREA.
SIDED WITH WARMEST GUIDANCE TONIGHT.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/...
COLD FRONT WILL BE EAST OF OUR AREA SUNDAY NIGHT AS ANY QPF LEFT
OVER ASSOCIATED WITH BAROCLINIC ZONE WILL AFFECT NRN WV MTNS AND
WRN MD UNTIL MID EVENING. A BRIEF PERIOD OF CLEARING MON EVENING
BEFORE CLOUDS ASSOCIATED WITH THE SURGE OF COLD AIR AND LOWER MID
LVL HEIGHTS ARRIVE FROM THE WEST.
MID LVL TROUGH SWEEPS THROUGH MON NGT - TUE. THIS IS ACCOMPANIED
BY MUCH COLDER AIR AS H8 TEMPS PLUMMET BACK INTO THE NEGATIVE MID
TEENS BY 12Z TUES. SCATTERED SNOW SHOWERS AND LAKE EFFECT SNOW
SHOWERS ARE PREDICTED MON NGT INTO TUES EVENING. WIND TRAJECTORY
IS NOT FAVORABLE FOR SIGNIFICANT SNOW ACCUMULATIONS. OUTSIDE THE
SNOW BELT OF NWRN PA...LOOK FOR MINOR ACCUMS AT BEST GIVEN SHORT
DURATION AND LACK OF FAVORABLE SNOW DYNAMICS AS NEEDED UPPER LEVEL
TEMPERATURES ARE BELOW REGION OF UPWARD VERTICAL MOTION.
ANTICYCLONIC FLOW RAPIDLY ENSUES DURING THE PREDAWN HOURS WEDNESDAY.
THIS WILL SHUT OFF THE LAKE EFFECT MACHINE AS SCOUR OUT CLOUDS.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
FOCUSED EFFORTS ON NEAR AND SHORT TERM TODAY...LATEST NUMERICAL
MODELS REMAIN CONSISTENT WITH WEATHER PATTER OVER THE LONG RANGE.
BELOW NORMAL TEMPS ARE PROJECTED FOR MUCH OF THE EXTENDED.
PREVIOUS DISCUSSION FOLLOWS:
BLDG HIGH PRES SHOULD END ANY SNOW SHWRS TUE EVE...WITH DRY WEATHER
CONTG WED. A WK CLIPPER IS PROGGED FOR THU...THOUGH TIMING AND
STRENGTH DIFFERENCES IN THE MDLS PRECLUDE MORE THAN A SLGT CHC
MENTION FOR SNOW SHWRS ATTM. BLDG HIGH PRES IS EXPD AGAIN BY THE
END OF THE WK. OVERALL...TEMPS SHOULD AVG BLO SEASONAL LVLS THRU
THE PD.
&&
.AVIATION /21Z SATURDAY THROUGH THURSDAY/...
FRONTAL BOUNDARY STALLED ACROSS NW PA WILL LIFT NORTH THIS EVENING
AND ALLOW FOR A BREAK IN PRECIP FOR TERMINALS
SOUTH OF I80 THIS OVERNIGHT. DUJ AND FKL HOWEVER ARE MORE LIKELY
TO SEE SHOWERS ONGOING THROUGH THE NIGHT WITH CONTINUED MVFR
CONDITIONS. FOR SOUTHERN TERMINALS...EXPECT MAINLY VFR BY EARLY EVENING
AND WITH SOUTHWESTERLY WINDS HELPING KEEP THINGS WELL MIXED
OVERNIGHT...DO NOT ANTICIPATE ANY ADDITIONAL VISIBILITY
RESTRICTIONS DEVELOPING.
.OUTLOOK.../18Z SUNDAY THROUGH THURSDAY/...
CONTINUED IFR RESTRICTIONS WILL BE POSSIBLE MONDAY NIGHT THROUGH
TUESDAY NORTH OF INTERSTATE 80 DUE TO LAKE EFFECT SNOW SHOWERS.
OTHERWISE...NO OTHER WIDESPREAD WEATHER RELATED AVIATION HAZARDS
EXISTS.
&&
.HYDROLOGY...
A FLOOD WARNING IS IN EFFECT FOR WILLS CREEK AT CAMBRIDGE
AFFECTING GUERNSEY COUNTY AND THE MUSKINGUM RIVER AT COSHOCTON
AFFECTING COSHOCTON COUNTY. RAINFALL AMOUNTS OF 1.00 TO NEARLY
3.00 INCHES OF RAINFALL ARE EXPECTED OVER THE TUSCARAWAS RIVER AND
MUSKINGUM RIVER BASINS.
SHARP RISES ARE EXPECTED ON RIVERS AND STREAMS ACROSS EASTERN OHIO.
THESE RISES WILL BE SUFFICIENT FOR THE MUSKINGUM RIVER AT COSHOCTON
TO RISE ABOVE FLOOD STAGE SUNDAY AFTERNOON. WILLS CREEK WILL RISE
ABOVE FLOOD STAGE SUNDAY EVENING. MINOR FLOODING IS EXPECTED AT BOTH
LOCATIONS.
A FLOOD ADVISORY IS IN EFFECT FOR THE OHIO RIVER AT THE POINT IN
PITTSBURGH. THE OHIO RIVER IS EXPECTED TO RISE ABOVE 18.0 FEET AND
BEGIN TO FLOOD THE MONONGAHELA RIVER PARKING WHARF SUNDAY AFTERNOON.
THE OHIO RIVER THE CREST IS EXPECTED MONDAY AFTERNOON AT 21.8 FEET.
THIS WILL COMPLETELY FLOOD THE MONONGAHELA PARKING WHARF. AT THIS
TIME FLOOD WATERS ARE NOT EXPECTED TO AFFECT THE 10TH STREET
BYPASS. STRONG RISES ON THE OHIO RIVER ARE FORECAST SUNDAY WITH
CONTINUED ELEVATED LEVELS THROUGH TUESDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...FLOOD WATCH THROUGH SUNDAY AFTERNOON FOR OHZ039>041-048-057.
PA...FLOOD WATCH THROUGH SUNDAY AFTERNOON FOR PAZ007>009-013.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
307 PM EST SAT DEC 21 2013
.SYNOPSIS...
A STRONG COLD FRONT ACCOMPANIED BY GUSTY WINDS PASSES SUNDAY.
AREA RIVERS WILL BE ON THE RISE THROUGH MONDAY. AN UPPER LEVEL
DISTURBANCE BRINGS SNOW SHOWERS MONDAY NIGHT INTO TUESDAY. MUCH
CALMER WEATHER THE BALANCE OF THE HOLIDAY WEEK WITH BELOW NORMAL
TEMPERATURES.
&&
.NEAR TERM /THROUGH SUNDAY/...
SOUTHERLY FLOW CONTINUES TO INCREASE AHEAD OF DEEPENING SFC CYCLONE
WHICH IS EVIDENT BY VIEWING REGIONAL RADAR MOSAIC AS PLUME OF RAIN
CONTINUES TO SHIFT NNE. DRY WEATHER HAS ALREADY REACHED NRN WV AND
WRN MD AND WILL CONTINUE TO OVERSPREAD MUCH OF THE CWA THIS
EVENING. PARTIAL CLEARING OVER THE NORTHERN WV MOUNTAINS HAS
ALLOWED TEMPS TO SOAR INTO THE MID 70S. THIS AIR WILL MAKE IT TO
THE MASON DIXON LINE...WHILE 60S SHALL ENCOMPASS WRN PA AND THE
NRN WV PANHANDLE. TEMPS WILL NOT FALL MUCH TONIGHT AS BOUNDARY
LAYER REMAINS WELL MIXED.
COLD FRONT CROSSES SUNDAY MORNING INTO EARLY AFTERNOON. BAND OF
MODERATE TO HEAVY SHOWERS WILL BE OUT AHEAD OF IT. THERMODYNAMIC
PARAMETERS STILL ARE NOT OVERLY IMPRESSIVE DUE TO THE TIME OF DAY
IT CROSSES. UPPER LEVEL DYNAMICS DO NOT WOW ME EITHER AS STRONG
AGEOSTROPHIC FORCING RESULTING FROM JET COUPLING IS NOT PRESENT.
CONTINUED TO OMIT THUNDER FROM FCST...DESPITE SPC BRINGING SLIGHT
RISK TO NRN WV PANHANDLE. GUSTY WINDS UPWARDS OF 40 MPH MAY OCCUR BASED
ON MOMENTUM TRANSFER. THIS COULD KNOCK AROUND OUTDOOR CHRISTMAS
DECORATIONS. HRRR AGREES WITH THIS BASED ON 10M WIND GUST FIELD.
HEAVY RAIN REMAINS A CONCERN ACROSS THE FLOOD WATCH AREA. AT THIS
TIME...ADDITIONAL AMOUNTS UPWARDS OF AN INCH COULD LEAD TO
FLOODING. THE PERIOD OF DRY WEATHER THIS EVENING HELPS OFFSET A
WIDESPREAD THREAT OF HIGH WATER IN THE WATCH AREA.
SIDED WITH WARMEST GUIDANCE TONIGHT.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/...
COLD FRONT WILL BE EAST OF OUR AREA SUNDAY NIGHT AS ANY QPF LEFT
OVER ASSOCIATED WITH BAROCLINIC ZONE WILL AFFECT NRN WV MTNS AND
WRN MD UNTIL MID EVENING. A BRIEF PERIOD OF CLEARING MON EVENING
BEFORE CLOUDS ASSOCIATED WITH THE SURGE OF COLD AIR AND LOWER MID
LVL HEIGHTS ARRIVE FROM THE WEST.
MID LVL TROUGH SWEEPS THROUGH MON NGT - TUE. THIS IS ACCOMPANIED
BY MUCH COLDER AIR AS H8 TEMPS PLUMMET BACK INTO THE NEGATIVE MID
TEENS BY 12Z TUES. SCATTERED SNOW SHOWERS AND LAKE EFFECT SNOW
SHOWERS ARE PREDICTED MON NGT INTO TUES EVENING. WIND TRAJECTORY
IS NOT FAVORABLE FOR SIGNIFICANT SNOW ACCUMULATIONS. OUTSIDE THE
SNOW BELT OF NWRN PA...LOOK FOR MINOR ACCUMS AT BEST GIVEN SHORT
DURATION AND LACK OF FAVORABLE SNOW DYNAMICS AS NEEDED UPPER LEVEL
TEMPERATURES ARE BELOW REGION OF UPWARD VERTICAL MOTION.
ANTICYCLONIC FLOW RAPIDLY ENSUES DURING THE PREDAWN HOURS WEDNESDAY.
THIS WILL SHUT OFF THE LAKE EFFECT MACHINE AS SCOUR OUT CLOUDS.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
FOCUSED EFFORTS ON NEAR AND SHORT TERM TODAY...LATEST NUMERICAL
MODELS REMAIN CONSISTENT WITH WEATHER PATTER OVER THE LONG RANGE.
BELOW NORMAL TEMPS ARE PROJECTED FOR MUCH OF THE EXTENDED.
PREVIOUS DISCUSSION FOLLOWS:
BLDG HIGH PRES SHOULD END ANY SNOW SHWRS TUE EVE...WITH DRY WEATHER
CONTG WED. A WK CLIPPER IS PROGGED FOR THU...THOUGH TIMING AND
STRENGTH DIFFERENCES IN THE MDLS PRECLUDE MORE THAN A SLGT CHC
MENTION FOR SNOW SHWRS ATTM. BLDG HIGH PRES IS EXPD AGAIN BY THE
END OF THE WK. OVERALL...TEMPS SHOULD AVG BLO SEASONAL LVLS THRU
THE PD.
&&
.AVIATION /19Z SATURDAY THROUGH THURSDAY/...
FRONTAL BOUNDARY STALLED ACROSS NW PA WILL LIFT NORTH THROUGH THE
AFTERNOON AND SHOULD ALLOW FOR A BREAK IN PRECIP FOR TERMINALS
SOUTH OF I80 THIS EVENING AND OVERNIGHT. DUJ AND FKL
HOWEVER ARE MORE LIKELY TO SEE SHOWERS ONGOING THROUGH THE NIGHT
WITH CONTINUED MVFR CONDITIONS. FOR SOUTHERN TERMINALS...EXPECT
MAINLY VFR BY LATE THIS AFTERNOON AND OVERNIGHT...AND WITH
SOUTHWESTERLY WINDS HELPING KEEP THINGS WELL MIXED OVERNIGHT...;DO
NOT ANTICIPATE ANY ADDITIONAL VISIBILITY RESTRICTIONS DEVELOPING.
.OUTLOOK.../18Z SUNDAY THROUGH THURSDAY/...
IFR RESTRICTIONS ARE POSSIBLE MON NGT INTO TUE ACROSS FKL AND DUJ
WITH LAKE EFFECT SNOW SHOWERS. BRIEF MVFR RESTRICTIONS COULD AFFECT
PIT AND LBE DURING THE AFOREMENTIONED TIME FRAME AS WELL.
OTHERWISE...NO OTHER WIDESPREAD WEATHER RELATED AVIATION HAZARDS
EXISTS.
&&
.HYDROLOGY...
A FLOOD WARNING IS IN EFFECT FOR WILLS CREEK AT CAMBRIDGE
AFFECTING GUERNSEY COUNTY AND THE MUSKINGUM RIVER AT COSHOCTON
AFFECTING COSHOCTON COUNTY. RAINFALL AMOUNTS OF 1.00 TO NEARLY
3.00 INCHES OF RAINFALL ARE EXPECTED OVER THE TUSCARAWAS RIVER AND
MUSKINGUM RIVER BASINS.
SHARP RISES ARE EXPECTED ON RIVERS AND STREAMS ACROSS EASTERN OHIO.
THESE RISES WILL BE SUFFICIENT FOR THE MUSKINGUM RIVER AT COSHOCTON
TO RISE ABOVE FLOOD STAGE SUNDAY AFTERNOON. WILLS CREEK WILL RISE
ABOVE FLOOD STAGE SUNDAY EVENING. MINOR FLOODING IS EXPECTED AT BOTH
LOCATIONS.
A FLOOD ADVISORY IS IN EFFECT FOR THE OHIO RIVER AT THE POINT IN
PITTSBURGH. THE OHIO RIVER IS EXPECTED TO RISE ABOVE 18.0 FEET AND
BEGIN TO FLOOD THE MONONGAHELA RIVER PARKING WHARF SUNDAY AFTERNOON.
THE OHIO RIVER THE CREST IS EXPECTED MONDAY AFTERNOON AT 21.8 FEET.
THIS WILL COMPLETELY FLOOD THE MONONGAHELA PARKING WHARF. AT THIS
TIME FLOOD WATERS ARE NOT EXPECTED TO AFFECT THE 10TH STREET
BYPASS. STRONG RISES ON THE OHIO RIVER ARE FORECAST SUNDAY WITH
CONTINUED ELEVATED LEVELS THROUGH TUESDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...FLOOD WATCH THROUGH SUNDAY AFTERNOON FOR OHZ039>041-048-057.
PA...FLOOD WATCH THROUGH SUNDAY AFTERNOON FOR PAZ007>009-013.
WV...NONE.
&&
$$
SYNOPSIS...98
NEAR TERM...98
SHORT TERM...98
LONG TERM...98/07
AVIATION...88
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
338 PM EST SAT DEC 21 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 457 AM EST SAT DEC 21 2013
SW FLOW ALOFT BTWN UPPER LOW OVER HUDSON BAY AND STRONG SOUTHERN
STREAM DISTURBANCE OVER NEW MEXICO. THROUGH TONIGHT...MAIN ISSUES
ARE TIED TO LAKE EFFECT. SOUTHERN STREAM WAVE LIFTS TOWARD UPPER GREAT
LAKES LATER TONIGHT...THOUGH IT APPEARS MAJORITY OF WIDESPREAD SNOW
WITH THE DEVELOPING LOW PRESSURE SYSTEM WILL REMAIN JUST SOUTH OF CWA
UNTIL DAYBREAK ON SUNDAY.
EMBEDDED SHORTWAVES/PV ANOMALIES IN FLOW ALOFT HELPING TO SUSTAIN
LGT SNOW/FLURRIES OVER CWA EARLY THIS MORNING. ALSO A BAND OF
ENHANCED LK EFFECT MAINLY OVER SCNTRL AND SOUTHEAST PORTIONS OF LK
SUPERIOR. RAP...WHICH DOES HAVE DECENT HANDLE ON BACK EDGE OF LGT
SNOW CURRENTLY...INDICATES MID-LEVEL MOISTURE/UVM EXITS EAST HALF
OF CWA THROUGH AROUND DAYBREAK THIS MORNING SO WOULD EXPECT LGT SNOW
TO END FOR A TIME. AT THE LEAST THE CLOUDS WILL CONTINUE TO HOLD UP
TEMPS THIS MORNING MAINLY IN THE TEENS. MILD FOR SURE COMPARED TO
THE RECENT CHILL UPR LAKES HAS EXPERIENCED. CURRENTLY THERE IS A SFC
TROUGH ACROSS THE AREA EXTENDING TO THE NW OF SFC LOW NEAR DETROIT.
EXPECT TROUGHING TO PERSIST THROUGH MUCH OF THE DAY WHILE GRADUALLY
GETTING PUSHED TO THE SOUTH AND EAST BY THIS AFTN AS HIGH PRESSURE
OVR SASKATCHEWAN AND MANITOBA TRIES TO RIDGE ACROSS LK SUPERIOR
REGION. THE MAIN IMPACT THIS HAS IS ON WIND FIELDS AND ASSOCIATED
LAKE EFFECT AS THERE IS ENOUGH INSTABILITY WITH INVERSIONS UP TO
5-7KFT AND TEMPS AT INVERSION TOP AROUND -13C WHILE WATER TEMPS ARE
AROUND +3C. SOUNDINGS AT P59/CMX AND STDM4 INDICATE DECENT
SUBSIDENCE ABOVE MOIST LAKE EFFECT LAYER AND ALSO NOT AS MUCH LIFT
WITHIN THE DGZ. IF CONVERGENCE CAN PERSIST OVER THE KEWEENAW
TODAY...THEN THERE IS AN OPPORTUNITY FOR ADVY LEVEL SNOW AMOUNTS.
CONFIDENCE IS LOW ON THIS POTENTIAL AND EVEN LOWER ON EXACTLY WHERE
THAT WOULD OCCUR. FOLLOWED GEM-REGIONAL THROUGH TODAY FOR WINDS
ALONG WITH NAM AND LOCAL-WRF MODEL BASED ON RAP BOUNDARY CONDITIONS.
THIS BLEND ESSENTIALLY HANGS UP MAIN CONVERGENCE AREA OVER NORTHERN
KEWEENAW THEN EVENTUALLY DRAWS IT SOUTH ACROSS THE PENINSULA THIS
AFTN AS THE HIGH BUILDS TOWARD LK SUPERIOR. SINCE INSTABILITY IS NOT
EXTREME OR OVER THE TOP BY ANY MEANS...FCST SNOW AMOUNTS FROM 2-4
INCHES...GREATEST NEAR MOHAWK/EAGLE RIVER/COPPER HARBOR. DESPITE
MODELS NOT SHOWING MUCH OCCURRING FOR OTHER AREAS WHERE FLOW IS
ONSHORE NEAR LK SUPERIOR...WENT WITH PERSISTENCE AND KEPT MENTION OF
SNOW OVER FAR WESTERN UPR MICHIGAN AND ALSO IN NCNTRL UPR MICHIGAN.
ANY AMOUNTS FOR THESE AREAS TODAY WILL JUST A DUSTING OF LESS THAN 1
INCH.
MINOR ISSUE FOR TODAY IS SKY COVER AND TEMPS. MODELS STRUGGLING WITH
EVENTUAL EVOLUTION OF LOW MVFR CLOUDS FM LK SUPERIOR BACK INTO CNTRL
MINNESOTA. NAM/RAP/GEM-REGIONAL SHOW THESE CLOUDS TO START BUT SEEM
TOO QUICK TO GET RID OF THEM OVER ALL BUT WESTERN CWA BY LATER
MORNING. WE WILL SEE ON THIS. IF MORE SUN OCCURS...MAX TEMPS MAY
PUSH WELL INTO THE MID-UPR 20S CNTRL. BASED ON CURRENT SATELLITE/OBS
TRENDS AND WITH SUN ANGLE ABOUT AS LOW AS IT GETS...WILL KEEP SKIES
MOSTLY CLOUDY FOR TODAY. LATER TODAY WILL BE A MOOT POINT AS
INCREASING NE WINDS SHOULD RESULT IN EXPANSION OF CLOUDS OFF LK
SUPERIOR.
SOUTHERN STREAM WAVE/LOW PRESSURE SYSTEM AFFECTS WILL BE KNOCKING ON
THE DOOR OF UPR MICHIGAN SO TO SPEAK LATER TONIGHT. NAM/GFS/ECMWF
LOOKED SIMILAR WITH PLACEMENT OF H5 TROUGH/PRIMARY PV ANAMOLY/H85
AND SFC LOWS. GEM WAS FARTHER NORTH WITH H85 LOW. SEEMED THAT ECMWF
WAS A NICE MIDDLE GROUND BTWN FARTHER SOUTH NAM/GFS WITH ADVANCING
WIDESPREAD SNOW AND MORE AGRESSIVE GEM. BROUGHT LIKELY POPS FOR
SYNOPTIC SNOW INTO FAR SCNTRL BY 09Z SUNDAY. OTHER IMPACT WILL BE
INCREASING FAVORABLE LAKE EFFECT OVER FAR WEST/KEWEENAW AND NCNTRL
CWA. NOT EXPECTING A LOT OF SNOW AS ANY LARGE SCALE FORCING IS
MINIMAL THROUGH 12Z...BUT THERE IS ENOUGH EVIDENCE IN FCST SOUNDINGS
THAT LAKE EFFECT WILL BE DEVELOPED ENOUGH TO RESULT IN LIKELY POPS
WITH MINOR SNOW AMOUNTS. SETUP BECOMES MUCH MORE FAVORABLE FOR
SIGNIFICANT LAKE ENHANCEMENT FOR SUNDAY AND BEYOND. BTWN THE LAKE
EFFECT MOISTURE/SNOW AND MID-HIGH CLOUDS ARRIVING FROM THE
SOUTH...EXPECT TEMPS TONIGHT TO STAY IN THE TEENS AGAIN.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 337 PM EST SAT DEC 21 2013
A LOW PRESSURE SYSTEM MOVING THROUGH THE SRN GREAT LAKES REGION
SUN...WHICH WILL BRING SYNOPTIC SNOW TO THE FAR SERN CWA AND LAKE
ENHANCED SNOW TO MUCH OF THE REST OF THE CWA THROUGH SUN. WITH THE
LONG TERM FORECAST STARTING AT 00Z MON...ALMOST ALL OF THE SYNOPTIC
PRECIP ASSOCIATED WITH THE PREVIOUSLY MENTIONED LOW WILL BE E OF THE
CWA. MORE SYNOPTIC SNOW WILL BE OVER OR JUST W OF THE FAR WRN CWA AT
00Z MON ASSOCIATED WITH A DEEP UPPER TROUGH OVER MN. THE TROUGH WILL
MOVE TO THE CENTRAL CWA BY 00Z TUE THEN E OF THE CWA BY 06Z TUE.
MODELS ARE IN GOOD AGREEMENT ON THE TROUGH WITH THE EXCEPTION OF THE
12Z/21 NAM WHICH HAS THE TROUGH DEEPER AND NEGATIVELY TILTED AND
SEEMS TOO AMPLIFIED. SHOULD SEE AN INVERTED SFC TROUGH STRETCHING
FROM THE SE ACROSS LAKE SUPERIOR THROUGH MUCH OF TUE NIGHT BEFORE A
SFC AND UPPER RIDGE MOVE ON ON TUE.
LAKE ENHANCED SNOW WILL BE ONGOING IN THE NNE-NE LOW LEVEL FOR AT
00Z MON WITH 850MB TEMPS AROUND -15C. WIND FIELDS SHOULD ONLY BACK
SLIGHTLY THROUGH MON...THEN MORE QUICKLY ON MON NIGHT...SO THE
PRIMARY AREAS FAVORED BY THE LAKE ENHANCEMENT WILL BE MARQUETTE AND
BARAGA COUNTIES AS WELL AS GOGEBIC AND ONTONAGON COUNTIES. MODERATE
TO HEAVY SNOW IS EXPECTED OVER THE WRN FAVORED AREAS THROUGH
MON...AND INTO MON NIGHT OVER THE NCENTRAL. IN COORDINATION WITH
SHORT TERM FORECASTER...LAKE EFFECT SNOW ADVISORIES WERE ISSUED FOR
THESE TWO AREAS. GENERALLY...EXPECT SNOW TO BY STEADY...WITH
ADDITIONAL SNOWFALL AMOUNTS SUN NIGHT INTO MON NIGHT OF AROUND A
FOOT OVER THE FAR WRN U.P. AND 8-12 INCHES OVER THE NCENTRAL.
MAINLY FOCUSED ON THE PREVIOUSLY DISCUSSED SHORTER TERM OF THE
FORECAST...BUT WILL BRIEFLY SUMMARIZE MORE SIGNIFICANT CHANGES TO
THIS PART OF THE FORECAST. KEPT POPS HIGHER THAN CONSENSUS FOR TUE
NIGHT THROUGH THU AS LAKE EFFECT AND ENHANCED SNOW IS NOT CAPTURED
WELL BE LOW RES MODELS. A COUPLE OF PERIODS OF COLDER WEATHER ARE IN
STORE...FOR SUN NIGHT THROUGH TUE AND WED NIGHT THROUGH FRI
NIGHT...THE LOWEST TEMPS SHOULD BE MON NIGHT AND THU NIGHT WHERE
TEMPERATURES MAY FALL INTO THE TEENS BELOW ZERO INTERIOR W AND FAR E
ON MON NIGHT AND OVER THE INTERIOR W ON THU NIGHT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1243 PM EST SAT DEC 21 2013
KIWD...LIGHT WINDS BECOMING ONSHORE NE DIRECTION SHOULD ENSURE MVFR
CIGS AND LIGHT LAKE SNOW SHOWERS ACROSS THE TAF SITES BY LATE THIS
AFTERNOON. IFR VSBY IN SNOW AND BLSN IS EXPECTED TO DEVELOP AT WRN
TAF SITES LATE TONIGHT ESPECIALLY AS NE WINDS AND INSTABILITY
INCREASES OVER WRN LAKE SUPERIOR. WINDS BECOMING MORE EASTERLY WILL
SCATTER OUT THE LOW CLOUDS AT SAW LATE TONIGHT. WIDESPREAD SNOW IS
EXPECTED TO IMPACT ALL TERMINALS ON SUNDAY AS A LOW PRESSURE SYSTEM
SLIDES ACROSS THE CENTRAL GREAT LAKES REGION. HEAVIEST SNOW WILL
OCCUR AT IWD WITH UPSLOPE NORTHEAST WINDS PROVIDING ADDITIONAL
SUPPORT FOR SNOW OFF LK SUPERIOR. AS A RESULT...VSBYS AT KIWD COULD
LOWER TO LIFR BY LATE SUNDAY MORNING.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 457 AM EST SAT DEC 21 2013
LIGHT WINDS TODAY WITH TROUGH OVER THE LAKE THEN AS THE TROUGH SINKS
SOUTH TONIGHT...EXPECT STRONG AND GUSTY NORTHEAST WINDS TO 30 KTS
OVER MUCH OF LAKE SUPERIOR INTO SUNDAY...FURTHER STRENGTHENED BY LOW
PRESSURE LIFTING ACROSS LOWER MICHIGAN. COULD BE GALE GUSTS OVER
THE WEST WITH CHANNELING BETWEEN MINNESOTA SHORELINE AND KEWEENAW
PENINSULA. DURING THIS PERIOD OF STRONGER WINDS THERE WILL BE
FREEZING SPRAY. EXPECT THE LOW TO LINGER A SURFACE TROUGH OVER THE
UPPER GREAT LAKES THROUGH MONDAY AND KEEP WINDS UP TO 25 KTS. HIGH
PRESSURE WILL CROSS THE UPPER GREAT LAKES ON MONDAY NIGHT...WHILE A
LOW PRESSURE SYSTEM BEGINS TO TAKE SHAPE IN THE CANADIAN PRAIRIES.
THIS LOW WILL LEAD TO INCREASING SOUTHERLY WINDS ACROSS LAKE
SUPERIOR ON TUESDAY. WHEN THE LOW MOVES THROUGH THE REGION ON
WEDNESDAY...WINDS WILL BECOME WESTERLY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY FROM 9 AM TO 5 PM EST SUNDAY FOR MIZ007-
013-014-085.
LAKE EFFECT SNOW ADVISORY FROM 1 AM EST /MIDNIGHT CST/ SUNDAY TO
MIDNIGHT EST /11 PM CST/ MONDAY NIGHT FOR MIZ002-009.
WINTER WEATHER ADVISORY FROM 5 AM TO 2 PM CST SUNDAY FOR MIZ012.
LAKE EFFECT SNOW ADVISORY FROM 7 AM SUNDAY TO 7 AM EST TUESDAY
FOR MIZ004-005.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING FROM 6 AM EST /5 AM CST/ TO 3 PM
EST /2 PM CST/ SUNDAY FOR LSZ162.
HEAVY FREEZING SPRAY WARNING FROM 7 AM SUNDAY TO 7 AM EST MONDAY
FOR LSZ263-264.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLA
LONG TERM...TITUS
AVIATION...VOSS
MARINE...JLA
AREA FORECAST DISCUSSION
NWS GAYLORD MI
216 PM EST SAT DEC 21 2013
.SYNOPSIS...
ISSUED AT 457 AM EST SAT DEC 21 2013
QUIET WEATHER IS EXPECTED DURING THE DAY TODAY BEFORE ANOTHER STORM
SYSTEM AFFECTS THE REGION TONIGHT INTO SUNDAY. THIS EVOLVING SYSTEM
WILL LIFT INTO THE NORTHERN OHIO VALLEY SATURDAY NIGHT...BRINGING
LIGHT TO MODERATE AMOUNTS OF SNOW TO THE REGION. COLD AIR WILL
FILTER BACK INTO THE GREAT LAKES MONDAY AND TUESDAY...GENERATING
SOME LAKE EFFECT SNOW...ACROSS PARTS OF NORTHERN MICHIGAN TO BEGIN
THE UPCOMING WORK WEEK. A COUPLE OF ALBERTA CLIPPERS WILL THEN
LIKELY BRINGING SOME LIGHT SNOW FOR CHRISTMAS DAY AND A CHANCE FOR
LIGHT SNOW ON THURSDAY.
&&
.UPDATE...
ISSUED AT 215 PM EST SAT DEC 21 2013
NO BIG CHANGES...HAVE DECREASED SKY COVER ACROSS EASTERN UPPER
MICHIGAN WITH FILTERED SUN UP THAT WAY. REMAINS TO BE SEEN IF SOME
OF THAT LOW LEVEL CLEARING CAN GET DOWN INTO THE TIP OF THE MITT
COUNTIES OR NOT. WILL SEE.
OTHERWISE...PATCHY FREEZING DRIZZLE APPEARS TO HAVE ENDED AND CIGS
ARE COMING UP A BIT...THUS NO NEED TO EXTEND -FZDZ AT THIS POINT.
TO OUR SOUTH...INVERTED SFC TROUGH STRETCHES FROM THE WESTERN GULF
UP THROUGH NEW ENGLAND WITH WIDESPREAD PRECIP ALREADY OCCURRING
ALONG THAT CONVERGENCE AXIS. ANTICIPATED STRONG SHORT WAVE MOVING
THE NRN TEXAS AND ABOUT TO SWING UP THROUGH THE CENTRAL PLAINS AND
INTO THE MIDWEST TONIGHT THEN SWING UP THROUGH LOWER MICHIGAN
DURING THE DAY. SFC LOW ON TRACK TO SPIN UP ALONG THE BAROCLINIC
ZONE AND ADVANCE UP THROUGH NRN OHIO/FAR SE LOWER MICHIGAN EARLY
SUNDAY MORNING BEFORE KICKING INTO THE EASTERN GREAT LAKES THROUGH
THE DAY. ONGOING WARM CONVEYOR PRECIP ALREADY TO OUR SOUTH
WILL INITIALLY PUSH UP INTO PARTS OF NRN LOWER MICHIGAN LATER
TONIGHT BEFORE GETTING PINCHED OFF AND KICKED INTO THE EASTERN
LAKES SUNDAY...FOLLOWED BY A PERIOD OF HEAVIER WRAP AROUND/
DEFORMATION SNOW THROUGH THE DAY SUNDAY...PERIOD OF HEAVIEST SNOW
BETWEEN 15Z AND 21Z AS THE SHORT WAVE SWINGS UP THROUGH LOWER
MICHIGAN.
LITTLE HAS CHANGED WITH THIS SCENARIO AMONGST GUIDANCE SOLUTIONS
OVER THE LAST DAY...AND THE NAM SOLUTION IS STILL THE FURTHER
NORTHERN SOLUTION...TRACKING THE SFC LOW INTO THE THUMB BUT
INTERESTINGLY KEEPS WARM NOSE ALOFT (>0C LAYER) JUST OUT OF THIS
CWA. SO ALL GUIDANCE SOURCES GIVE NRN LOWER MICHIGAN SNOW...WITH
JUST AN OUTSIDE CHANCE OF SLEET OVER THE FAR SE COUNTIES TOWARD
SAGINAW BAY. ONLY MAIN DIFFERENCES AT THIS POINT IS JUST WHERE
HEAVIEST WRAP AROUND QPF BULLSEYE TRACKS THROUGH THE REGION...
AGAIN WITH THE NAM A LITTLE FURTHER NORTHWARD DISPLACED. BUT OUR
CONSENSUS FORECAST KEEPS HEAVIEST QPF BULLSEYE TRACKING RIGHT UP
ACROSS NRN LOWER MICHIGAN...POSSIBLY SKIMMING FAR EASTERN UPPER
MICHIGAN WITH SOME HEAVIER SNOW.
AS FAR AS SNOW AMOUNTS GO...BASICALLY HAVE A 2 PERIOD (TONIGHT AND
TOMORROW) COMBINED TOTAL OF 0.4 TO 0.6 INCHES TOTAL LIQUID OVER
NRN LOWER MICHIGAN...0.2 TO 0.4 INCHES IN EASTERN UPPER MICHIGAN.
SNOW ACCUMULATIONS WILL OF COURSE BE DEPENDENT ON JUST WHAT
SNOW:WATER RATIOS ARE REALIZED. HAVE <10:1 RATIOS OVER THE S/SE
COUNTIES AND 10-15:1 FOR NRN HALF OF THE CWA...YIELDING A NICE 4
TO 7 INCHES SWEET SPOT CENTERED UP THROUGH NRN LOWER MICHIGAN AND
LESSER AMOUNTS TOWARD SAGINAW BAY. NOT MUCH DIFFERENT WITH WHAT WE
HAVE BEEN FORECASTING FOR THE LAST DAY OR TWO. PLAN NO CHANGES TO
THE CURRENT WINTER WEATHER ADVISORIES...ALTHOUGH WE MAY PUT
EASTERN UPPER MICHIGAN INTO AN ADVISORY FOR SOME BEEFIER SNOWFALL
OVER THE EASTERN PART OF THOSE COUNTIES.
UPDATE ISSUED AT 1028 AM EST SAT DEC 21 2013
NO MAJOR CHANGES TO THE FORECAST AT THIS HOUR...AND AN OVERALL
QUIET...ALBEIT CLOUDY DAY ON TAP FOR THE NORTH WOODS. 12Z APX
REVEALING A FAIRLY DEEP SATURATED LOW LAYER UP TO NEARLY 750
MB...ALTHOUGH THE TEMP/DEWPOINT SPREAD DOES OPEN A BIT IN LAYERS.
NONETHELESS...HAVE HAVE A FEW REPORTS OF -FZDZ AROUND THE TVC AREA
AND OBS AROUND THE GRAND TRAVERSE BAY AREA DOES HINT AT PATCHY
FZDZ VIA REDUCED VSBYS AND LOW CIGS. EVEN GLR REPORTING LOW VSBY
AND FZFG. SO...HAVE ADDED PATCHY -FZDZ TO THE FORECAST THROUGH THE
MORNING AND EVEN ISSUED AN SPS TO COVER SOME POTENTIAL SLICK
SPOTS/BLACK ICE THIS MORNING. RUC FORECAST SOUNDINGS SHOW ONGOING
LOW LEVEL DRYING/OPENING THE SOUNDINGS JUST A BIT THROUGH THE
AFTERNOON...SUGGESTING -FZDZ WILL END. WILL SEE.
OTHERWISE...JUST INGESTING OBSERVATIONAL TRENDS AND INCOMING 12Z
GUIDANCE TO SEE WHAT...IF ANY ADJUSTMENTS MAY BE NEEDED TO THE
UPCOMING EVENT LATER TONIGHT THROUGH SUNDAY. NO BIG SURPRISES SO
FAR.
UPDATE ISSUED AT 628 AM EST SAT DEC 21 2013
UPDATED SKY GRIDS. WINDS ARE TURNING LIGHT OUT OF THE NORTH WITH
LITTLE TO NO SPEEDS REMAINING 5 KTS OR LESS. SLOWED ANY SORT OF
GOOD LOW LEVEL DRYING AND AM KEEPING LOW CLOUDS AROUND THROUGH A
GOOD PORTION OF THE DAY...PLUS A PLETHORA OF MID AND HIGH LEVEL
CLOUDS REMAINS OVER MUCH OF THE REGION AND DO NOT SEE MUCH
HAPPENING WITH THAT TODAY. THUS...CLOUDY FOR MOST OF THE
DAY...THIS IS ESPECIALLY TRUE ACROSS THE SE CWA WHERE LOW LEVEL
MOISTURE WILL BE RICH/THICK ENOUGH FOR CLOUDS. NO PRECIPITATION
EXPECTED FOR THE DAY.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 457 AM EST SAT DEC 21 2013
CURRENTLY...SPLIT FLOW IN THE UPPER LEVELS WITH A NRN STREAM JET
STREAK OVERHEAD...AND A SRN STREAM JET STREAK LIFTING INTO OK WHICH
IS EJECTED FROM A CUT OFF LOW OVER FAR WEST TX. IN THE NRN
STREAM...WE HAVE ONE WEAK AND SHEARED OUT VORT MAX RUNNING INTO
EASTERN LAKE SUPERIOR...WHICH HAS CONTINUED TO PRODUCE LIGHT
SNOW/FLURRY RETURNS ON MQT RADAR WHICH WERE WORKING UP THROUGH
WESTERN SECTIONS OF CHIP/MACK COUNTIES OF EASTERN UPPER. H8 LLJ
FORCING IS COMPLETELY DONE AS WIND DIRECTIONS HAVE VEERED WEST...AND
ACTUALLY DRYING WAS UNDERWAY FROM NORTH TO SOUTH. THIS ALSO HELPING
TO KEEP ANY LIGHT SNOW AT BAY ACROSS EASTERN UPPER. PECULIAR EARLIER
WEAK RADAR RETURNS EMANATING FROM ANTRIM INTO CRAWFORD COUNTY HAS
BEEN A VERY FINE LIGHT SNOW...AND THIS WAS ALSO ERODING...LIKELY DUE
TO THE NOW H8 DRYING. TOTAL MOISTURE IN THE COLUMN IS DRYING...AND
WILL NOW BE SLOWLY ERODING ANY CHANCE OF PRECIP AND PATCHY FREEZING
DRIZZLE...THE LATTER OF WHICH SEEMS TO BE ISOLATED AT BEST...WITH
ONLY CADILLAC OBSERVATION SUGGESTING THE POSSIBILITY OF FREEZING
DRIZZLE...AND ACTUALLY BELIEVE THAT IS MORE OF A LOWERING
CEILING/FREEZING FOG TYPE THING. DO NOT BELIEVE THAT THIS IS ANY
SERIOUS IMPACT.
TODAY AND TONIGHT...WEAK/SHEARED OUT VORT MAX WILL EXIT EAST OVER
THE NEXT COUPLE OF HOURS WITH H8 DRYING CONTINUING TO SLIDE
SOUTH...ENDING ALL LIGHT SNOW IN EASTERN UPPER. WINDS DO VEER MORE
NORTHERLY INTO THE DAYLIGHT HOURS...AND LOW LEVEL TEMPS RESULT IN
DELTA T`S SUFFICIENT ENOUGH FOR MAYBE A FEW FLURRIES ACROSS FAR NE
LOWER. OUTSIDE OF THAT...A QUIET PERIOD OF WEATHER FOR THE
DAY...WITH DEEP SW FLOW ALOFT...ABOVE THE SHALLOW COLDER AIR. THIS
WILL CONTINUE TO BRING IN MIDDLE AND UPPER LEVEL CLOUDS. DO NOT SEE
THE NORTHERLY FLOW BEING STRONG ENOUGH TO SCOUR OUT THE LOW LEVEL
CLOUDS ACROSS THE SE PART OF THE CWA. THIS WILL RESULT IN A RETURN A
DEEPLY SATURATED ATMOSPHERE IN THE AFTERNOON. WE WILL SEE SOME WEAK
ENERGY EJECTED FROM THE SRN STREAM CUT OFF WORKING IN OVER THE FAR
SE CWA LATE IN THE AFTERNOON FOR THE FIRST CHANCES FOR SEEING SOME
LIGHT SNOW FALL. STRONGER ENERGY/MODERATE DEEP LAYER -DIVQ ARRIVES
OVERNIGHT...AS THE ATMOSPHERE DEEPENS IN MOISTURE. THIS WILL MAINLY
BE ACROSS NRN LOWER. THE DEEP MOISTURE IS BROUGHT IN BY A WIDE OPEN
GULF (CURRENTLY STREAMING DEEP LOW LEVEL MOISTURE INTO THE OHIO
RIVER VALLEY) ARRIVES VIA STRONG LOW LEVEL JET. AS THE SRN STREAM
CUT OFF OPENS UP AND LIFTS INTO ILLINOIS LATE TONIGHT/DAYBREAK
TOMORROW...THE SFC LOW DEEPENS SOME...AND WINDS BACK...ALLOWING THE
BEST LOW LEVEL MOISTURE TURN GET LIFTED FURTHER NORTH INTO OUR NECK
OF THE WOODS. AT THE SAME TIME...STRONG DEEP LAYER -DIVQ IS SETTLED
IN ON US...AND SNOWS WILL PICK UP IN INTENSITY. CAN SEE AROUND A
COUPLE OF INCHES BY DAYBREAK ACROSS THE SE CWA...LESSENED NEAREST
THE SAG BAY BY LOW LIQUID-SNOW RATIOS AND THE POSSIBILITY (IF WARMER
NAM IS RIGHT) OF A MIX WITH SLEET.
FOR A DISCUSSION ON THE WATCH SITUATION...SEE BELOW.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 457 AM EST SAT DEC 21 2013
AN ACTIVE WEATHER PATTERN ALONG WITH COLD TEMPERATURES CONTINUE
THROUGH THE FORECAST PERIOD WITH A MEAN TROUGH REMAINING IN PLACE
ACROSS CENTRAL CANADA INTO THE GREAT LAKES REGION. IN
ADDITION...UPPER LEVEL DISTURBANCES MOVING THROUGH THE FLOW ALOFT
WILL BRING NUMEROUS CHANCES FOR SNOW SHOWERS...ENHANCED FROM TIME TO
TIME BY THE BIG LAKES. MEANWHILE...THE WELL ADVERTISED SOUTHERN JET
STREAM SYSTEM COULD STILL POTENTIALLY BRING WHAT LOOKS LIKE A
MODERATE AMOUNT OF SNOW TO REGION LATER SATURDAY NIGHT INTO SUNDAY.
THE MAIN LONG TERM FORECAST CONCERNS REVOLVE AROUND SNOW AMOUNTS FOR
SATURDAY NIGHT INTO SUNDAY THEN THE USUAL SUSPECTS...POPS AND
TEMPERATURES FOR THE REMAINDER OF THE FORECAST.
SUNDAY...SOUTHERN BRANCH ENERGY MOVES NORTHWARD ALONG A TIGHTENING
BAROCLINIC ZONE. LATEST MODEL RUNS CONTINUE TO HAVE A MODEST AREA OF
LOW PRESSURE AT THE SURFACE TRACKING ACROSS EITHER NORTHERN OHIO
(MAJORITY OF MODELS) OR SOUTHWEST LOWER MICHIGAN (INCONSISTENT AND
CONTINUED OUTLIER NAM). THERE IS STILL THE POTENTIAL FOR LAKE
ENHANCEMENT OFF OF LAKE HURON ACROSS NORTHEAST LOWER AS A POCKET OF
COLDER AIR (850 MB TEMPS -10 TO -12 C) TRIES TO SYNC UP WITH THE
TAIL END OF DEEP SYNOPTIC MOISTURE. OVERALL...A GENERAL LIGHT TO
MODERATE SNOWFALL IS STILL EXPECTED WITH STORM TOTAL AMOUNTS OF
BETWEEN 4 AND 8 INCHES OF GREASY SNOW WHICH WILL BE COVERED WITH A
WINTER WEATHER ADVISORY FOR ALL COUNTIES OF NORTHERN LOWER MICHIGAN.
WILL STILL HAVE TO BE COGNIZANT OF POSSIBLE SNEAKY LAKE ENHANCEMENT
ADDING TO THE TOTALS ACROSS NORTHEAST LOWER. MEANWHILE...ACROSS
EASTERN UPPER...2 TO 3 INCHES OF ACCUMULATION IS EXPECTED. HIGHS
RANGING FROM THE UPPER TEENS TO MIDDLE 20S...BUT LIKELY FALLING OFF
IN THE AFTERNOON AS COLD AIR ADVECTION KICKS IN.
SUNDAY NIGHT...WRAP AROUND MOISTURE/DEFORMATION ZONE AXIS SITS OVER
THE REGION. THIS WILL LIKELY BRING SOME LIGHT SNOW...WITH ADDITIONAL
ACCUMULATIONS OF ONE TO PERHAPS TWO INCHES. LOWS RANGING FROM THE
COLDER SINGLE DIGITS ABOVE ZERO TO THE MIDDLE TEENS.
MONDAY AND MONDAY NIGHT...A NORTHERN STREAM TROUGH ALONG WITH
ANOTHER SHOT OF ARCTIC AIR (850 MB TEMPS DOWN TO -20 C OR SO) DROPS
DOWN INTO THE REGION BRINGING ADDITIONAL CHANCES FOR MAINLY LIGHT
SNOW. THE FLOW IS RATHER LIGHT OVERALL BUT MAY STILL BE JUST STRONG
ENOUGH TO PRODUCE SOME LAKE EFFECT (GENERALLY OUT OF THE NORTH
NORTHWEST). HOWEVER...AM NOT EXPECTING BIG TIME ACCUMULATIONS WITH
MODEL SOUNDINGS SHOWING INVERSION HEIGHTS OF ONLY AROUND 3000 FEET
OR SO PLUS SNOWFLAKE SIZES WILL LIKELY BE RATHER SMALL. HIGHS MAINLY
IN THE TEENS. LOWS RANGING FROM THE COLDER SINGLE DIGITS TO THE
MIDDLE TEENS.
TUESDAY...PERHAPS SOME LINGERING NORTH NORTHWEST FLOW LAKE EFFECT IN
THE MORNING. OTHERWISE...ARCTIC HIGH PRESSURE PRESSES DOWN FROM THE
NORTH YIELDING VERY COLD TEMPERATURES AND PERHAPS CLEARING SKIES (IF
WE CAN SCOUR OUT THE LIKELY STUBBORN STRATUS). HIGHS ONLY EXPECTED
TO RANGE FROM THE UPPER SINGLE DIGITS (ABOVE ZERO) TO THE MIDDLE
TEENS. LOWS IN THE SINGLE DIGITS ABOVE AND BELOW ZERO AT NIGHT.
WEDNESDAY THROUGH FRIDAY...A PARADE OF SHORT WAVES DROP DOWN THROUGH
THE FLOW. EXTENDED MODELS CONTINUE TO VARY ON THE EXACT TIMING AND
DETAILS SO WILL NOT GET TOO FANCY...AND HAVE GENERAL CHANCES FOR
SNOW SHOWERS. THERE COULD BE SOME LAKE ENHANCEMENT AS WELL FROM TIME
TO TIME...BUT PINNING DOWN THE EXACT FLOW REGIMES IS NEARLY
IMPOSSIBLE THIS FAR OUT. HIGHS IN THE MIDDLE TO UPPER 20S WEDNESDAY
THEN COOLING OFF AGAIN INTO THE UPPER TEENS TO MIDDLE 20S FOR
THURSDAY AND THE MIDDLE TEENS TO AROUND 20 FOR FRIDAY. LOWS IN THE
TEENS WEDNESDAY NIGHT THEN THE SINGLE DIGITS FOR THURSDAY AND FRIDAY
NIGHTS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 215 PM EST SAT DEC 21 2013
CIGS HAVE SLOWLY INCREASE ACROSS NRN LOWER MICHIGAN OVER THE LAST
FEW HOURS...WITH ALL TERMINAL SITES MVFR OR BETTER. CONDITIONS
WILL LARGELY REMAIN UNCHANGED THROUGH THIS EVENING. SNOWFALL WILL
BEGIN TO NUDGE INTO THE REGION SOUTH-NORTH LATE TONIGHT REACHING
THE TAF SITES BETWEEN 08Z AND 12Z. CIGS/VSBYS WILL LOWER TO LOW
MVFR OR IFR AND REMAIN THERE THROUGH MUCH OF SUNDAY.
LIGHT NORTHEASTERLY WINDS THROUGH THIS AFTERNOON. BUT NE-E WINDS
INCREASE TONIGHT AND BECOME A BIT GUSTY FOR SUNDAY (GUSTS INTO THE
20 TO 25 KNOT RANGE) AS LOW PRESSURE TRACKS BY TO OUR SOUTH.
&&
.MARINE...
ISSUED AT 457 AM EST SAT DEC 21 2013
A LIGHT EASTERLY WINDS REGIME WILL BRIEFLY TURN NORTHERLY OVER MANY
OF THE NEARSHORE WATERS THIS MORNING...BEFORE RETURNING TO EASTERLY
AND INCREASING THROUGH TONIGHT. THIS DUE TO STRENGTHENING LOW
PRESSURE THAT WILL LIFT THROUGH DETROIT. A PERIOD OF ADVISORY LEVEL
WINDS WILL DEVELOP TONIGHT...BEFORE DYING BACK OFF SUNDAY NIGHT INTO
MONDAY WITH THE APPROACH OF HIGHER PRESSURE. THESE LIGHTER WINDS
CONTINUE INTO TUESDAY.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY FROM 1 AM TO 7 PM EST SUNDAY FOR
MIZ016>036-041-042.
LH...SMALL CRAFT ADVISORY FROM 7 PM THIS EVENING TO 7 PM EST SUNDAY
FOR LHZ345>349.
LM...SMALL CRAFT ADVISORY FROM 7 PM THIS EVENING TO 7 PM EST SUNDAY
FOR LMZ323-341-342-344>346.
LS...SMALL CRAFT ADVISORY FROM 7 PM THIS EVENING TO 7 PM EST SUNDAY
FOR LSZ321-322.
&&
$$
UPDATE...BA
SYNOPSIS...AS
SHORT TERM...SD
LONG TERM...AS
AVIATION...BA
MARINE...SD
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
105 PM EST SAT DEC 21 2013
LATEST UPDATE...
HYDRO
.SYNOPSIS...
ISSUED AT 1245 PM EST SAT DEC 21 2013
A STORM SYSTEM APPROACHING FROM THE SOUTHWEST WILL AFFECT THE AREA
WITH A VARIETY OF WINTER WEATHER BEGINNING THIS EVENING. SOUTH
CENTRAL LOWER MICHIGAN WILL LIKELY EXPERIENCE FREEZING RAIN AND
ICE ACCUMULATION WHERE TEMPERATURES SHOULD HOVER AROUND FREEZING.
FURTHER NORTH INTO CENTRAL LOWER MICHIGAN...THE PRECIPITATION TYPE
WILL TRANSITION TO A WINTRY MIX AND EVENTUALLY TO A HEAVY WET
SNOW.
WINTRY PRECIPITATION WILL TAPER OFF SUNDAY AFTERNOON AND EVENING.
MUCH COLDER AIR WILL FILTER IN BEHIND THE SYSTEM FOR AT LEAST
THROUGH CHRISTMAS DAY. SNOW WILL DEVELOP AGAIN LATE SUNDAY NIGHT AND
INTO MONDAY WITH THE POTENTIAL FOR SOME ACCUMULATIONS. THERE WILL
BE ADDITIONAL CHANCES FOR SNOW THROUGH THE WORK WEEK.
&&
.UPDATE...
ISSUED AT 945 AM EST SAT DEC 21 2013
DENSE FOG IS BECOMING AN INCREASING CONCERN THIS MORNING MAINLY
ALONG AND SOUTH OF AN EAST-WEST SURFACE BOUNDARY LOCATED JUST
NORTH OF I-94. THERE ARE MANY REPORTS OF VISIBILITY AT OR BELOW
1/4 MILE ALONG AND SOUTH OF THIS BOUNDARY. HRRR GUIDANCE PUSHES
THE BOUNDARY SOUTH OF THE FORECAST AREA BY THIS AFTERNOON WITH
INCREASING WINDS FROM THE NORTHEAST...SO EXPECT DENSE FOG TO BE
LESS OF A CONCERN BY AFTERNOON. WILL HIGHLIGHT THE ONGOING FOG
CONCERN IN AN UPCOMING WSW UPDATE.
RADAR SHOWS THAT PRECIPITATION HAS BEGUN TO OVERSPREAD THE AREA
SOUTHEAST OF A MARSHALL TO MASON LINE. WE ARE A LITTLE CONCERNED
ABOUT AIR TEMPERATURES STAYING SUFFICIENTLY COLD FOR ICE
ACCUMULATION IN THE WARNED AREA. TEMPERATURES AND DEWPOINTS ARE
VERY CLOSE TO FREEZING. A POSITIVE FOR FREEZING RAIN IS COLDER
AND SLIGHTLY DRIER AIR UPSTREAM TO THE NORTHEAST. ALSO SEVERAL
MESONET SITES IN THE AREA ARE REPORTED TEMPERATURES BELOW
FREEZING. CURRENT EXPECTATIONS ARE THAT ICE ACCUMULATION ON
SECONDARY ROADS AND EXPOSED ROAD SURFACES REMAIN A DEFINITE
CONCERN. WILL BE CLOSELY MONITORING TEMPERATURE TRENDS OVER THE
NEXT FEW HOURS.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY NIGHT)
ISSUED AT 329 AM EST SAT DEC 21 2013
THE MAIN FOCUS OF THE SHORT TERM IS THE STORM SYSTEM EXPECTED TO
IMPACT THE AREA BEGINNING TODAY AND LASTING THROUGH SUNDAY. WE HAVE
TRANSITIONED THE HEADLINES FROM THE WATCH...TO AN ICE STORM WARNING
ACROSS THE FAR SE CORNER OF THE CWFA. ADVISORIES HAVE BEEN ISSUED
FOR THE REMAINDER OF THE CWFA FOR SNOW ACROSS THE NORTH AND A WINTRY
MIX ACROSS THE MIDDLE SECTION OF THE CWFA. NO MAJOR CHANGES IN THE
FCST HAVE BEEN MADE AS THE CONSENSUS OF THE MODELS IS GENERALLY
CONSISTENT WITH THE PREVIOUS RUNS.
WE WILL NEED TO DEAL WITH SOME FOG ISSUES ACROSS THE SOUTH THIS
MORNING.
THE GREATEST IMPACT OF THE INCOMING STORM SYSTEM LOOKS TO BE THE
THREAT OF RELATIVELY SIGNIFICANT AMOUNTS OF FREEZING RAIN/ICING
EXPECTED ROUGHLY SE OF I-69 LATER TODAY AND INTO THE EARLY OVERNIGHT
HOURS TONIGHT. WE EXPECT RAIN AND OR FREEZING RAIN TO START PUSHING
UP INTO THE SRN COUNTIES TOWARD THE AFTERNOON TODAY. AREAS ALONG AND
SOUTH OF I-94 COULD START OUT BARELY ABOVE FREEZING AT THE ONSET OF
PCPN. WE EXPECT ALL PCPN DOWN ACROSS THE SE CORNER TO TRANSITION TO
FREEZING RAIN AS THE COLD AND SOMEWHAT DRIER NE FLOW WILL BRING
TEMPS DOWN DUE TO ADVECTION AND EVAPORATIVE COOLING.
QPF ACROSS THE SE COUNTIES LOOKS TO BE OVER AN INCH THROUGH THE
EARLY OVERNIGHT HOURS AS THEY BARELY GET UNDER THE NRN PERIPHERY OF
THE BEST MOISTURE AXIS WITH THIS SYSTEM. AN ABOVE FREEZING LAYER
ALOFT IS MAINTAINED MOST OF THE TIME AS THE SFC TEMPS DROP TO AROUND
OR JUST BELOW FREEZING. NOT ALL OF THIS QPF WILL GO INTO THE ICING
EXPECTED DUE TO LATENT HEAT AND RUNOFF PROCESSES. HOWEVER WITH THAT
MUCH QPF...EVEN A PORTION OF IT FREEZING WILL CREATE A GOOD COATING
OF ICE...UP AROUND HALF AN INCH WILL BE LIKELY.
THE TRANSITION IN P-TYPE WILL BE SOMEWHAT TRICKY ACROSS THE CENTRAL
PORTION OF THE CWFA NW OF I-69 TO ROUGHLY M-20. HOWEVER WE EXPECT
THAT FREEZING RAIN AND SLEET TO BE MORE PREVAILING WITH SOME SNOW
POSSIBLE. A SLIGHT ABOVE FREEZING LAYER WILL BE PRESENT WITH THE
LAYER THINNER AND COOLER AS YOU MOVE NW. QPF AMOUNTS WILL BE QUITE A
BIT LESS AS THE MOISTURE AXIS REMAINS SE OF THIS AREA. IT WILL BE
TOUGH TO GET HIGH IMPACT FREEZING RAIN AMOUNTS IN THIS AREA. HOWEVER
ONE THING TO CONSIDER IS THE GLAZE IN PLACE ALREADY FROM THE THU
NIGHT/FRI EVENT.
THE PCPN IN BOTH OF THESE AREAS IS EXPECTED TO LIGHTEN UP
SIGNIFICANTLY BETWEEN 06-12Z SUN AS THE DRY SLOT IS EXPECTED TO MOVE
OVER THESE AREAS. SOME LIGHT PCPN WILL REMAIN...HOWEVER WE COULD
SEE IT TRANSITION TO FZDZ AS THE DGZ BECOMES UNSATURATED.
BY THE TIME PCPN REACHES THE NRN PORTION OF THE CWFA...THE COLUMN
SHOULD BE MAINLY COLD ENOUGH TO SUPPORT MAINLY SNOW. THE SNOW SHOULD
START OUT LIGHT...AND PICK UP LATE TONIGHT/SUN MORNING AS THE BEST
DEFORMATION SLIDES ACROSS THE NRN COUNTIES AND NW OF THE CWFA. SNOW
AMOUNTS ARE GENERALLY EXPECTED TO REMAIN IN THE ADVISORY CATEGORY AS
THE UPPER LOW EJECTING WILL HAVE OPENED UP BY THE TIME IT REACHES
HERE AND THE FGEN IN THE DEFORMATION WILL NOT BE AS STRONG AS TO OUR
SW. ONE THING GOING FOR BETTER SNOW AMOUNTS HERE IS THE FACT THAT
THE DGZ IS EXPECTED TO REMAIN SATURATED AS THE DRY SLOT REMAINS SE
OF THIS AREA.
THE CAVEAT TO ALL OF THIS IS IF THE OUTLIER NAM IS CORRECT...ALL OF
THIS WOULD BE SHIFTING TO THE NW A LITTLE. WE BELIEVE AT THIS TIME
THAT WE HAVE A GOOD CONSENSUS OF THE TRACK OF THE SYSTEM WITH GOOD
RUN TO RUN CONSISTENCY FROM MOST OF THE GLOBAL MODELS AND IT SHOULD
BE WELL SAMPLED BY NOW WITH IT BEING WELL WITHIN THE RAOB NETWORK.
WE WILL SEE A TRANSITION TO SOME LAKE EFFECT SNOW SHOWERS ON SUN
NIGHT AS COLDER AIR COMES IN BEHIND THE SYSTEM. THE FLOW SHOULD BE
NNW WHICH WOULD FAVOR THE IMMEDIATE LAKESHORE FOR BEST SNOW SHOWER
CHANCES. THERE IS SOME DECENT MOISTURE UP THROUGH 15K FEET AND
OVER-LAKE INSTABILITY IS SUFFICIENT.
.LONG TERM...(MONDAY THROUGH FRIDAY)
ISSUED AT 329 AM EST SAT DEC 21 2013
THE UPCOMING CHRISTMAS WEEK WILL BE MORE LIKE WHAT WE HAVE SEEN FOR
MUCH OF DECEMBER: COLDER THAN NORMAL WITH FREQUENT CHANCES FOR SNOW
SHOWERS. THE NORTHERN BRANCH OF THE JET AND ARCTIC AIR WILL DOMINATE
THROUGHOUT THE WEEK... WITH SEVERAL SHORTWAVES AND SFC
TROUGHS/FRONTS SWINGING THROUGH THE GRTLKS RGN. TEMPERATURES ARE
EXPECTED BE BELOW FREEZING ALL WEEK... AND THE COLDEST DAY OF THE
WEEK WILL BE TUESDAY WHEN HIGHS SHOULD STRUGGLE TO REACH 20 BEHIND
THE FIRST NRN STREAM WAVE.
GFS/ECMWF ARE IN GOOD AGREEMENT SHOWING A POTENT SHORTWAVE IMPACTING
THE AREA MONDAY AFTERNOON AND NIGHT. SNOW SHOWERS ARE LIKELY AND
LAKE ENHANCEMENT WILL BE IN PLAY AS THIS FEATURE COMES THROUGH.
HOWEVER CONFIDENCE IN WIND DIRECTION IS LOW SINCE MODELS INDICATE A
WEST TO EAST ORIENTED SFC TROUGH SETTING UP SOMEWHERE ACROSS LWR MI
AND ARE NOT IN GREAT AGREEMENT WITH IT/S LOCATION AND RESULTANT
WINDS. NEVERTHELESS THE TROUGH SHOULD RESULT IN LOCALLY ENHANCED
CONVERGENCE WITH A LARGE PORTION OF THE CWFA SEEING SNOW SHOWERS AND
AT LEAST SOME LIGHT ACCUMULATIONS. IF A WESTERLY FLOW DEVELOPS THEN
AREAS ALONG AND WEST OF HWY 131 COULD SEE SEVERAL INCHES BUT AGAIN
WIND DIRECTION IS VERY QUESTIONABLE AT THIS TIME.
A BRIEF PERIOD OF SHORTWAVE RIDGING MOVES ACROSS FOR TUESDAY
AFTERNOON AND EVENING... THEN SOME WAA/ISENTROPIC LIFT LIGHT SNOW
POSSIBLE ON CHRISTMAS DAY AHEAD OF THE NEXT APPROACHING SHORTWAVE.
THE ECMWF HAS A MUCH STRONGER SHORTWAVE THAN THE GFS FOR THE 26TH
AND WOULD SUGGEST A DECENT ROUND OF ACCUMULATING LAKE ENHANCED SNOW
SHOWERS FOR THURSDAY AND THURSDAY NIGHT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1258 PM EST SAT DEC 21 2013
WIDESPREAD LIFR ACROSS THE REGION THIS AFTERNOON. NOT EXPECTING
MUCH OVERALL CHANGE OVER THE NEXT 24 HOURS. THE DIFFICULT ASPECT
OF THE FORECAST IS DETERMINING WHEN PCPN WILL OCCUR AT THE TAF
SITES AND WHAT TYPE OF PCPN WILL FALL.
RATHER THAN A LONG DURATION OF PCPN...IT APPEARS WE WILL SEE A
PERIOD OF PCPN THIS EVENING...THEN AS A DRY SLOT COMES IN...THE
PCPN MAY END FOR A BIT OVERNIGHT...THEN ANOTHER PERIOD OF PCPN
SHOULD OCCUR FOR MUCH OF SUN MORNING.
AS FOR PCPN TYPE...THE RAIN TO WINTRY MIX LINE RAN FROM NEAR BIV
TO TEW AT 17Z. THIS APPEARS TO CHANGE LITTLE INTO TONIGHT...WHICH
MEANS THE I-94 TAF SITE SHOULD REMAIN RIGHT ON THE EDGE OF THE
ICY PCPN. HAVE GONE MORE OPTIMISTIC WITH LIQUID PCPN AT THE I-94
TAF SITES...BUT THIS IS A VERY CLOSE CALL...AND WE WILL CONTINUE
TO MONITOR.
MEANWHILE THE I-96 TAF SITES CAN CONTINUE TO EXPECT PERIODS OF
FREEZING RAIN WHICH SHOULD BEGIN TO SWITCH TO SNOW AND/OR SLEET
MID/LATE SUNDAY MORNING.
&&
.MARINE...
ISSUED AT 534 PM EST FRI DEC 20 2013
NORTHEAST FLOW WILL CONTINUE INTO SATURDAY NIGHT. THIS OFFSHORE FLOW
WILL HELP KEEP WAVES LOWER. HOWEVER AS WINDS PIVOT TO THE NORTH
NORTHWEST LATE SATURDAY NIGHT/EARLY SUNDAY MORNING WAVES WILL BUILD
AND WE WILL LIKELY NEED A SMALL CRAFT ADVISORY BY THEN.
&&
.HYDROLOGY...
ISSUED AT 103 PM EST SAT DEC 21 2013
THE HEADWATERS OF THE GRAND AND ST. JOSEPH RIVER BASINS ARE EXPECTED
TO RECEIVE AROUND 0.75 INCHES OR LESS WITH THIS EVENT. BEST CHANCE
FOR FLOODING REMAINS TO THE SOUTH IN NORTHERN INDIANA AND NORTHWEST
OHIO. A SHARP RISE BELOW FLOOD STAGE OF THE GRAND RIVER AT JACKSON
IS EXPECTED...BUT THIS RISE WILL BE BRIEF AND SHOULD FALL QUICKLY.
STORM EVOLUTION WILL BE MONITORED CLOSELY FOR HEAVIER PRECIP AMOUNTS
OVER THE GRAND HEADWATERS.
TEMPERATURES ARE HOVERING NEAR FREEZING TODAY. SNOW MELT COULD
CONTRIBUTE TO RISES AS WELL. ICE BREAKUP AND MOVEMENT COULD CAUSE
RIVER RISES ON SUNDAY WITH TEMPS REACHING THE UPPER 30S IN SOUTH
CENTRAL LOWER MICHIGAN.
ARCTIC AIR STREAMS BACK IN ON SUNDAY NIGHT. MONDAY NIGHT AND TUESDAY
NIGHT ARE EXPECTED TO BE VERY COLD...WITH LOWS IN THE SINGLE DIGITS
POSSIBLE. ICE DEVELOPMENT ON RIVERS IS EXPECTED...SO THE RISK FOR
ICE JAM FLOODING INCREASES. TEMPS WILL STAY BELOW FREEZING THROUGH
ALL OF NEXT WEEK.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL NOON EST SUNDAY FOR MIZ051-052-
056>059-064-065-071-072.
ICE STORM WARNING UNTIL 7 AM EST SUNDAY FOR MIZ066-067-073-074.
WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 7 PM EST
SUNDAY FOR MIZ037>040-043>046-050.
LM...NONE.
&&
$$
UPDATE...TJT
SYNOPSIS...JAM
SHORT TERM...NJJ
LONG TERM...MEADE
AVIATION...JK
HYDROLOGY...EBW
MARINE...JK
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1254 PM EST SAT DEC 21 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 457 AM EST SAT DEC 21 2013
SW FLOW ALOFT BTWN UPPER LOW OVER HUDSON BAY AND STRONG SOUTHERN
STREAM DISTURBANCE OVER NEW MEXICO. THROUGH TONIGHT...MAIN ISSUES
ARE TIED TO LAKE EFFECT. SOUTHERN STREAM WAVE LIFTS TOWARD UPPER GREAT
LAKES LATER TONIGHT...THOUGH IT APPEARS MAJORITY OF WIDESPREAD SNOW
WITH THE DEVELOPING LOW PRESSURE SYSTEM WILL REMAIN JUST SOUTH OF CWA
UNTIL DAYBREAK ON SUNDAY.
EMBEDDED SHORTWAVES/PV ANOMALIES IN FLOW ALOFT HELPING TO SUSTAIN
LGT SNOW/FLURRIES OVER CWA EARLY THIS MORNING. ALSO A BAND OF
ENHANCED LK EFFECT MAINLY OVER SCNTRL AND SOUTHEAST PORTIONS OF LK
SUPERIOR. RAP...WHICH DOES HAVE DECENT HANDLE ON BACK EDGE OF LGT
SNOW CURRENTLY...INDICATES MID-LEVEL MOISTURE/UVM EXITS EAST HALF
OF CWA THROUGH AROUND DAYBREAK THIS MORNING SO WOULD EXPECT LGT SNOW
TO END FOR A TIME. AT THE LEAST THE CLOUDS WILL CONTINUE TO HOLD UP
TEMPS THIS MORNING MAINLY IN THE TEENS. MILD FOR SURE COMPARED TO
THE RECENT CHILL UPR LAKES HAS EXPERIENCED. CURRENTLY THERE IS A SFC
TROUGH ACROSS THE AREA EXTENDING TO THE NW OF SFC LOW NEAR DETROIT.
EXPECT TROUGHING TO PERSIST THROUGH MUCH OF THE DAY WHILE GRADUALLY
GETTING PUSHED TO THE SOUTH AND EAST BY THIS AFTN AS HIGH PRESSURE
OVR SASKATCHEWAN AND MANITOBA TRIES TO RIDGE ACROSS LK SUPERIOR
REGION. THE MAIN IMPACT THIS HAS IS ON WIND FIELDS AND ASSOCIATED
LAKE EFFECT AS THERE IS ENOUGH INSTABILITY WITH INVERSIONS UP TO
5-7KFT AND TEMPS AT INVERSION TOP AROUND -13C WHILE WATER TEMPS ARE
AROUND +3C. SOUNDINGS AT P59/CMX AND STDM4 INDICATE DECENT
SUBSIDENCE ABOVE MOIST LAKE EFFECT LAYER AND ALSO NOT AS MUCH LIFT
WITHIN THE DGZ. IF CONVERGENCE CAN PERSIST OVER THE KEWEENAW
TODAY...THEN THERE IS AN OPPORTUNITY FOR ADVY LEVEL SNOW AMOUNTS.
CONFIDENCE IS LOW ON THIS POTENTIAL AND EVEN LOWER ON EXACTLY WHERE
THAT WOULD OCCUR. FOLLOWED GEM-REGIONAL THROUGH TODAY FOR WINDS
ALONG WITH NAM AND LOCAL-WRF MODEL BASED ON RAP BOUNDARY CONDITIONS.
THIS BLEND ESSENTIALLY HANGS UP MAIN CONVERGENCE AREA OVER NORTHERN
KEWEENAW THEN EVENTUALLY DRAWS IT SOUTH ACROSS THE PENINSULA THIS
AFTN AS THE HIGH BUILDS TOWARD LK SUPERIOR. SINCE INSTABILITY IS NOT
EXTREME OR OVER THE TOP BY ANY MEANS...FCST SNOW AMOUNTS FROM 2-4
INCHES...GREATEST NEAR MOHAWK/EAGLE RIVER/COPPER HARBOR. DESPITE
MODELS NOT SHOWING MUCH OCCURRING FOR OTHER AREAS WHERE FLOW IS
ONSHORE NEAR LK SUPERIOR...WENT WITH PERSISTENCE AND KEPT MENTION OF
SNOW OVER FAR WESTERN UPR MICHIGAN AND ALSO IN NCNTRL UPR MICHIGAN.
ANY AMOUNTS FOR THESE AREAS TODAY WILL JUST A DUSTING OF LESS THAN 1
INCH.
MINOR ISSUE FOR TODAY IS SKY COVER AND TEMPS. MODELS STRUGGLING WITH
EVENTUAL EVOLUTION OF LOW MVFR CLOUDS FM LK SUPERIOR BACK INTO CNTRL
MINNESOTA. NAM/RAP/GEM-REGIONAL SHOW THESE CLOUDS TO START BUT SEEM
TOO QUICK TO GET RID OF THEM OVER ALL BUT WESTERN CWA BY LATER
MORNING. WE WILL SEE ON THIS. IF MORE SUN OCCURS...MAX TEMPS MAY
PUSH WELL INTO THE MID-UPR 20S CNTRL. BASED ON CURRENT SATELLITE/OBS
TRENDS AND WITH SUN ANGLE ABOUT AS LOW AS IT GETS...WILL KEEP SKIES
MOSTLY CLOUDY FOR TODAY. LATER TODAY WILL BE A MOOT POINT AS
INCREASING NE WINDS SHOULD RESULT IN EXPANSION OF CLOUDS OFF LK
SUPERIOR.
SOUTHERN STREAM WAVE/LOW PRESSURE SYSTEM AFFECTS WILL BE KNOCKING ON
THE DOOR OF UPR MICHIGAN SO TO SPEAK LATER TONIGHT. NAM/GFS/ECMWF
LOOKED SIMILAR WITH PLACEMENT OF H5 TROUGH/PRIMARY PV ANAMOLY/H85
AND SFC LOWS. GEM WAS FARTHER NORTH WITH H85 LOW. SEEMED THAT ECMWF
WAS A NICE MIDDLE GROUND BTWN FARTHER SOUTH NAM/GFS WITH ADVANCING
WIDESPREAD SNOW AND MORE AGRESSIVE GEM. BROUGHT LIKELY POPS FOR
SYNOPTIC SNOW INTO FAR SCNTRL BY 09Z SUNDAY. OTHER IMPACT WILL BE
INCREASING FAVORABLE LAKE EFFECT OVER FAR WEST/KEWEENAW AND NCNTRL
CWA. NOT EXPECTING A LOT OF SNOW AS ANY LARGE SCALE FORCING IS
MINIMAL THROUGH 12Z...BUT THERE IS ENOUGH EVIDENCE IN FCST SOUNDINGS
THAT LAKE EFFECT WILL BE DEVELOPED ENOUGH TO RESULT IN LIKELY POPS
WITH MINOR SNOW AMOUNTS. SETUP BECOMES MUCH MORE FAVORABLE FOR
SIGNIFICANT LAKE ENHANCEMENT FOR SUNDAY AND BEYOND. BTWN THE LAKE
EFFECT MOISTURE/SNOW AND MID-HIGH CLOUDS ARRIVING FROM THE
SOUTH...EXPECT TEMPS TONIGHT TO STAY IN THE TEENS AGAIN.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 457 AM EST SAT DEC 21 2013
HAVE OPTED TO ISSUE A WINTER STORM WATCH FOR THE TERRAIN/LAKE
ENHANCED AREAS OF MARQUETTE/BARAGA COUNTIES AS WELL AS GOGEBIC AND
ONTONAGON COUNTIES FOR SUNDAY AND MONDAY. LONG DURATION LAKE
ENHANCED/LAKE EFFECT SNOW EPISODE LOOKING MORE POSSIBLE NOW AS THE
MODELS ARE STARTING TO COME INTO BETTER AGREEMENT INTO A MAIN LOW
TRACK THROUGH SOUTHERN MI ON SUNDAY. HOWEVER...THE COMPLEX
INTERACTION BETWEEN THE SOUTHERN STREAM ENERGY MOVING THROUGH THE
LOWER LAKES AND THE NORTHERN STREAM TROUGH MOVING INTO THE UPPER
MIDWEST MAKES THIS FORECAST CONFIDENCE STILL SOMEWHAT BELOW AVERAGE.
ONTO THE DETAILS...AS SAID ABOVE THE NWP SUITE HAVE COME INTO BETTER
AGREEMENT WITH THE MAIN LOW MOVING THROUGH SOUTHERN LOWER MICHIGAN
WITH THE SOUTHERN STREAM IMPULSE MOVING OUT OF THE PLAINS. EXPECT
SYNOPTIC MOISTURE AND LIFT TO GLANCE BY THE SOUTHEAST FORECAST AREA
SUNDAY MORNING INTO EARLY AFTERNOON AS THE COMMA HEAD/DEFORMATION
ZONE PCPN MOVES THROUGH. THIS TRACK WILL ALLOW FOR 1000-850MB WINDS
TO TURN NE AND SHOULD ALLOW FOR LAKE ENHANCEMENT TO ALSO DEVELOP IN
MARQUETTE/BARAGA COUNTIES AS WELL AS THE FAR WEST NEAR IRONWOOD.
CONSENSUS QPF FROM THE NWP SUGGEST ABOUT 0.20-0.30 INCH OF QPF NEAR
LAKE MICHIGAN AND FAR EAST ON SUNDAY...WITH MUCH LESSER AMOUNTS WELL
INLAND AWAY FROM FROM LAKE SUPERIOR. THIS ALSO SEEMS REASONABLE
GIVEN THAT 700MB MIXING RATIOS REMAIN AROUND 2 G/KG THROUGH EARLY
AFTERNOON. GIVEN THAT SOME OF THE LIFT WILL BE IN THE DGZ AREA
ACROSS THE SOUTH DURING THE DAY...WE SHOULD SEE SNOW RATIOS ACROSS
THE FAR SOUTHEAST AROUND 15-17:1 DURING THE DAY WHICH WOULD EQUATE
TO 3-5 INCHES OF SNOW BY EVENING. MOST LIKELY AN ADVISORY WILL BE
NEEDED IN THIS AREA ON SUNDAY...BUT WILL HOLD OFF SINCE THIS WILL BE
GENERALLY A 3RD PERIOD ADVY.
AS FOR AREAS CLOSER TO LAKE SUPERIOR...ALL OF THE NWP GUIDANCE SHOW
PBL WINDS STAYING NELY THROUGH THE DAY WHICH SHOULD ALLOW FOR
TERRAIN ENHANCED SNOW TO COMMENCE IN THE NE FLOW FAVORED AREAS
DESPITE THE RELATIVELY WEAK SYNOPTIC LIFT. WITH THE BEST LIFT BEING
CONFINED TO GENERALLY BELOW THE DGZ...EXPECT SNOW RATIOS BE BE
FAIRLY LOW WITH ONLY AROUND 13:1. WILL GENERALLY GO WITH 4 OR 5
INCHES AT MOST IN THESE AREAS...BUT GIVEN THE STRONG AND DEEP NE
FLOW...WOULD NOT BE SHOCKED IF QPF AND THUS SNOWFALL IS MORE ON
SUNDAY.
THEN ON SUNDAY NIGHT...DIFFERENCE START TO DEVELOP WITH THE MODELS
REGARDING THE EVOLUTION OF THE NORTHERN STREAM UPPER TROUGH. THE NAM
IS CERTAINLY THE MOST AGGRESSIVE IN CLOSING OFF THE LOW AND
SETTLING OVER THE UPPER GREAT LAKES...WHICH ALLOW FOR A STRONG
INVERTED TROUGH TO HANG BACK ACROSS THE CENTRAL GREAT LAKES THROUGH
MONDAY. MEANWHILE...THE GFS GENERALLY KEEPS THE UPPER TROUGH OPEN
AND MOVES IN THROUGH THE AREA BY MONDAY AFTERNOON. THE LATEST 00Z
ECMWF IS INTERESTING AS IT ALSO ATTEMPT TO CLOSE OFF THE LOW SUN
NIGHT BUT IS NOT NEARLY AS DEEP AS THE NAM FORECASTS.
NONETHELESS...THE ECMWF ALSO SUGGESTS THAT THERE WILL BE SOME TYPE
OF INVERTED TROUGH EXTENDING BACK INTO THE AREA THROUGH MONDAY AND
OUR LOCALLY PRODUCE ARW-WRF USING THE GFS AS BOUNDARY CONDITIONS
ALSO SUGGEST THAT THERE WILL BE A INVERTED TROUGH HANGING BACK
THROUGH MONDAY. AS SUCH...DO NOT THINK THE PBL WINDS WILL SHIFT TO
N-NW AS FAST AS THE GFS AND ECMWF SUGGEST. IN FACT...THE CURRENT
THINKING IS THAT THE WINDS WILL STAY NORTHERLY OR PERHAPS A LITTLE
EAST OF NORTH THROUGH MONDAY WITH THIS TROUGH STAYING SOUTH OF THE
AREA. WITH ALL OF THIS SAID...THE EXPECTATION IS THAT THE SNOW WILL
TRANSITION TO MORE LAKE ENHANCED VARIETY AND PERSIST RIGHT THROUGH
MONDAY BEFORE THE UPPER TROUGH SWINGS THROUGH AND ALLOWS THE WIND TO
GRADUALLY SHIFT TO THE N-NW BY MON EVENING. AS SUCH...EXPECT
MODERATE TO LOCALLY HEAVY SNOW TO CONTINUE IN MQT/BARAGA COUNTIES AS
WELL AS GOGEBIC COUNTY THROUGH THE NIGHT SUNDAY INTO MONDAY. THE
BEST LIFT RAPIDLY BECOMING ENTRENCHED IN THE DGZ SUNDAY EVENING AS
THE UPPER TEMPS DROP...EXPECT THE SNOW TO BECOME MUCH MORE FLUFFY
BUT ALSO ACCUMULATE MUCH FASTER WITH RATIOS CLOSE TO 25:1 BY MON
MORNING. SOME AREAS IN THE WATCH AREA COULD SEE ANOTHER 8-12 INCHES
OF SNOW SUN NIGHT INTO MONDAY.
INTERESTINGLY...THERE ARE SEVERAL VERY GOOD CIPS ANALOG EVENTS FOR
THIS SYSTEM. THEY ALL GENERALLY SHOW THE WATCH AREA SEEING
SIGNIFICANT 72 HOUR SNOWFALL. NOT SURE IF WE WILL SEE ANY LONGER
PERIOD OF HEAVY SNOWFALL...RATHER I AM THINKING THAT IT WILL BE
GENERALLY A PERSISTENT SNOWFALL FOR 24-36 HOURS WHICH WILL ALLOW
WARNING CRITERIA TO BE REACHED. EVEN MORE INTERESTING...DESPITE THE
FACT THAT GOGEBIC COUNTY WILL BE FURTHEST REMOVED FROM THE
SYSTEM...THE CURRENT NWP AND ALSO THE CIPS GUIDANCE SUGGEST THAT
THIS AREA COULD SEE THE MOST SNOWFALL OUT OF THIS EVENT. WE WILL
SEE...
ANY REMAINING LES SHOULD END RAPIDLY MON NIGHT/TUE MORNING AS THE
HIGH PRES RIDGE BUILDS ACROSS THE FORECAST AREA. STILL LOOKS QUITE
COLD TUE MORNING ACROSS THE WEST WITH LIGHT WINDS/CLEAR SKIES. TEMPS
10-20 BELOW NOT OUT OF THE QUESTION IN THE NORMALLY COLDER SPOTS.
THE ECMWF AND GEM ARE IN GOOD AGREEMENT IN LIGHT OVERRUNNING/WARM
ADVECTION SNOW CHRISTMAS EVE NIGHT INTO CHRISTMAS DAY ACROSS THE
ENTIRE FORECAST AREA. SOME HINTS THAT THERE MIGHT BE SOME LAKE
ENHANCEMENT OFF OF LAKE MICHIGAN TUESDAY NIGHT AND HAVE OPTED TO
CONTINUE LIKELY POPS ACROSS THE EASTERN PART OF THE FORECAST AREA
TUE NIGHT INTO CHRISTMAS DAY. SOME DIFFERENCES EMERGE THU INTO
FRIDAY REGARDING THE EVOLUTION AND THE TROUGH WITH THE ECMWF BEING
DEEPER AND FURTHER SOUTH COMPARED TO THE GFS. REGARDLESS...SENSIBLE
WEATHER SHOULD GENERALLY THE SAME WITH EITHER MODEL WITH LES IN THE
NW FAVORED SNOWBELTS CHRISTMAS NIGHT INTO THU NIGHT BEFORE
DIMINISHING ON FRIDAY AS HIGH PRES BUILDS OVERHEAD. TEMPS STILL LOOK
BELOW NORMAL THROUGH THE EXTENDED WITH 850MB TEMPS -20 TO -25C WED
NIGHT/THU WARMING TO -15 TO -20C BY FRIDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1243 PM EST SAT DEC 21 2013
KIWD...LIGHT WINDS BECOMING ONSHORE NE DIRECTION SHOULD ENSURE MVFR
CIGS AND LIGHT LAKE SNOW SHOWERS ACROSS THE TAF SITES BY LATE THIS
AFTERNOON. IFR VSBY IN SNOW AND BLSN IS EXPECTED TO DEVELOP AT WRN
TAF SITES LATE TONIGHT ESPECIALLY AS NE WINDS AND INSTABILITY
INCREASES OVER WRN LAKE SUPERIOR. WINDS BECOMING MORE EASTERLY WILL
SCATTER OUT THE LOW CLOUDS AT SAW LATE TONIGHT. WIDESPREAD SNOW IS
EXPECTED TO IMPACT ALL TERMINALS ON SUNDAY AS A LOW PRESSURE SYSTEM
SLIDES ACROSS THE CENTRAL GREAT LAKES REGION. HEAVIEST SNOW WILL
OCCUR AT IWD WITH UPSLOPE NORTHEAST WINDS PROVIDING ADDITIONAL
SUPPORT FOR SNOW OFF LK SUPERIOR. AS A RESULT...VSBYS AT KIWD COULD
LOWER TO LIFR BY LATE SUNDAY MORNING.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 457 AM EST SAT DEC 21 2013
LIGHT WINDS TODAY WITH TROUGH OVER THE LAKE THEN AS THE TROUGH SINKS
SOUTH TONIGHT...EXPECT STRONG AND GUSTY NORTHEAST WINDS TO 30 KTS
OVER MUCH OF LAKE SUPERIOR INTO SUNDAY...FURTHER STRENGTHENED BY LOW
PRESSURE LIFTING ACROSS LOWER MICHIGAN. COULD BE GALE GUSTS OVER
THE WEST WITH CHANNELING BETWEEN MINNESOTA SHORELINE AND KEWEENAW
PENINSULA. DURING THIS PERIOD OF STRONGER WINDS THERE WILL BE
FREEZING SPRAY. EXPECT THE LOW TO LINGER A SURFACE TROUGH OVER THE
UPPER GREAT LAKES THROUGH MONDAY AND KEEP WINDS UP TO 25 KTS. HIGH
PRESSURE WILL CROSS THE UPPER GREAT LAKES ON MONDAY NIGHT...WHILE A
LOW PRESSURE SYSTEM BEGINS TO TAKE SHAPE IN THE CANADIAN PRAIRIES.
THIS LOW WILL LEAD TO INCREASING SOUTHERLY WINDS ACROSS LAKE
SUPERIOR ON TUESDAY. WHEN THE LOW MOVES THROUGH THE REGION ON
WEDNESDAY...WINDS WILL BECOME WESTERLY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER STORM WATCH FROM SUNDAY MORNING THROUGH MONDAY EVENING
FOR MIZ002-004-005-009.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLA
LONG TERM...MRD
AVIATION...VOSS
MARINE...JLA
AREA FORECAST DISCUSSION
NWS GAYLORD MI
1028 AM EST SAT DEC 21 2013
.SYNOPSIS...
ISSUED AT 457 AM EST SAT DEC 21 2013
QUIET WEATHER IS EXPECTED DURING THE DAY TODAY BEFORE ANOTHER STORM
SYSTEM AFFECTS THE REGION TONIGHT INTO SUNDAY. THIS EVOLVING SYSTEM
WILL LIFT INTO THE NORTHERN OHIO VALLEY SATURDAY NIGHT...BRINGING
LIGHT TO MODERATE AMOUNTS OF SNOW TO THE REGION. COLD AIR WILL
FILTER BACK INTO THE GREAT LAKES MONDAY AND TUESDAY...GENERATING
SOME LAKE EFFECT SNOW...ACROSS PARTS OF NORTHERN MICHIGAN TO BEGIN
THE UPCOMING WORK WEEK. A COUPLE OF ALBERTA CLIPPERS WILL THEN
LIKELY BRINGING SOME LIGHT SNOW FOR CHRISTMAS DAY AND A CHANCE FOR
LIGHT SNOW ON THURSDAY.
&&
.UPDATE...
ISSUED AT 1028 AM EST SAT DEC 21 2013
NO MAJOR CHANGES TO THE FORECAST AT THIS HOUR...AND AN OVERALL
QUIET...ALBEIT CLOUDY DAY ON TAP FOR THE NORTH WOODS. 12Z APX
REVEALING A FAIRLY DEEP SATURATED LOW LAYER UP TO NEARLY 750
MB...ALTHOUGH THE TEMP/DEWPOINT SPREAD DOES OPEN A BIT IN LAYERS.
NONETHELESS...HAVE HAVE A FEW REPORTS OF -FZDZ AROUND THE TVC AREA
AND OBS AROUND THE GRAND TRAVERSE BAY AREA DOES HINT AT PATCHY
FZDZ VIA REDUCED VSBYS AND LOW CIGS. EVEN GLR REPORTING LOW VSBY
AND FZFG. SO...HAVE ADDED PATCHY -FZDZ TO THE FORECAST THROUGH THE
MORNING AND EVEN ISSUED AN SPS TO COVER SOME POTENTIAL SLICK
SPOTS/BLACK ICE THIS MORNING. RUC FORECAST SOUNDINGS SHOW ONGOING
LOW LEVEL DRYING/OPENING THE SOUNDINGS JUST A BIT THROUGH THE
AFTERNOON...SUGGESTING -FZDZ WILL END. WILL SEE.
OTHERWISE...JUST INGESTING OBSERVATIONAL TRENDS AND INCOMING 12Z
GUIDANCE TO SEE WHAT...IF ANY ADJUSTMENTS MAY BE NEEDED TO THE
UPCOMING EVENT LATER TONIGHT THROUGH SUNDAY. NO BIG SURPRISES SO
FAR.
UPDATE ISSUED AT 628 AM EST SAT DEC 21 2013
UPDATED SKY GRIDS. WINDS ARE TURNING LIGHT OUT OF THE NORTH WITH
LITTLE TO NO SPEEDS REMAINING 5 KTS OR LESS. SLOWED ANY SORT OF
GOOD LOW LEVEL DRYING AND AM KEEPING LOW CLOUDS AROUND THROUGH A
GOOD PORTION OF THE DAY...PLUS A PLETHORA OF MID AND HIGH LEVEL
CLOUDS REMAINS OVER MUCH OF THE REGION AND DO NOT SEE MUCH
HAPPENING WITH THAT TODAY. THUS...CLOUDY FOR MOST OF THE
DAY...THIS IS ESPECIALLY TRUE ACROSS THE SE CWA WHERE LOW LEVEL
MOISTURE WILL BE RICH/THICK ENOUGH FOR CLOUDS. NO PRECIPITATION
EXPECTED FOR THE DAY.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 457 AM EST SAT DEC 21 2013
CURRENTLY...SPLIT FLOW IN THE UPPER LEVELS WITH A NRN STREAM JET
STREAK OVERHEAD...AND A SRN STREAM JET STREAK LIFTING INTO OK WHICH
IS EJECTED FROM A CUT OFF LOW OVER FAR WEST TX. IN THE NRN
STREAM...WE HAVE ONE WEAK AND SHEARED OUT VORT MAX RUNNING INTO
EASTERN LAKE SUPERIOR...WHICH HAS CONTINUED TO PRODUCE LIGHT
SNOW/FLURRY RETURNS ON MQT RADAR WHICH WERE WORKING UP THROUGH
WESTERN SECTIONS OF CHIP/MACK COUNTIES OF EASTERN UPPER. H8 LLJ
FORCING IS COMPLETELY DONE AS WIND DIRECTIONS HAVE VEERED WEST...AND
ACTUALLY DRYING WAS UNDERWAY FROM NORTH TO SOUTH. THIS ALSO HELPING
TO KEEP ANY LIGHT SNOW AT BAY ACROSS EASTERN UPPER. PECULIAR EARLIER
WEAK RADAR RETURNS EMANATING FROM ANTRIM INTO CRAWFORD COUNTY HAS
BEEN A VERY FINE LIGHT SNOW...AND THIS WAS ALSO ERODING...LIKELY DUE
TO THE NOW H8 DRYING. TOTAL MOISTURE IN THE COLUMN IS DRYING...AND
WILL NOW BE SLOWLY ERODING ANY CHANCE OF PRECIP AND PATCHY FREEZING
DRIZZLE...THE LATTER OF WHICH SEEMS TO BE ISOLATED AT BEST...WITH
ONLY CADILLAC OBSERVATION SUGGESTING THE POSSIBILITY OF FREEZING
DRIZZLE...AND ACTUALLY BELIEVE THAT IS MORE OF A LOWERING
CEILING/FREEZING FOG TYPE THING. DO NOT BELIEVE THAT THIS IS ANY
SERIOUS IMPACT.
TODAY AND TONIGHT...WEAK/SHEARED OUT VORT MAX WILL EXIT EAST OVER
THE NEXT COUPLE OF HOURS WITH H8 DRYING CONTINUING TO SLIDE
SOUTH...ENDING ALL LIGHT SNOW IN EASTERN UPPER. WINDS DO VEER MORE
NORTHERLY INTO THE DAYLIGHT HOURS...AND LOW LEVEL TEMPS RESULT IN
DELTA T`S SUFFICIENT ENOUGH FOR MAYBE A FEW FLURRIES ACROSS FAR NE
LOWER. OUTSIDE OF THAT...A QUIET PERIOD OF WEATHER FOR THE
DAY...WITH DEEP SW FLOW ALOFT...ABOVE THE SHALLOW COLDER AIR. THIS
WILL CONTINUE TO BRING IN MIDDLE AND UPPER LEVEL CLOUDS. DO NOT SEE
THE NORTHERLY FLOW BEING STRONG ENOUGH TO SCOUR OUT THE LOW LEVEL
CLOUDS ACROSS THE SE PART OF THE CWA. THIS WILL RESULT IN A RETURN A
DEEPLY SATURATED ATMOSPHERE IN THE AFTERNOON. WE WILL SEE SOME WEAK
ENERGY EJECTED FROM THE SRN STREAM CUT OFF WORKING IN OVER THE FAR
SE CWA LATE IN THE AFTERNOON FOR THE FIRST CHANCES FOR SEEING SOME
LIGHT SNOW FALL. STRONGER ENERGY/MODERATE DEEP LAYER -DIVQ ARRIVES
OVERNIGHT...AS THE ATMOSPHERE DEEPENS IN MOISTURE. THIS WILL MAINLY
BE ACROSS NRN LOWER. THE DEEP MOISTURE IS BROUGHT IN BY A WIDE OPEN
GULF (CURRENTLY STREAMING DEEP LOW LEVEL MOISTURE INTO THE OHIO
RIVER VALLEY) ARRIVES VIA STRONG LOW LEVEL JET. AS THE SRN STREAM
CUT OFF OPENS UP AND LIFTS INTO ILLINOIS LATE TONIGHT/DAYBREAK
TOMORROW...THE SFC LOW DEEPENS SOME...AND WINDS BACK...ALLOWING THE
BEST LOW LEVEL MOISTURE TURN GET LIFTED FURTHER NORTH INTO OUR NECK
OF THE WOODS. AT THE SAME TIME...STRONG DEEP LAYER -DIVQ IS SETTLED
IN ON US...AND SNOWS WILL PICK UP IN INTENSITY. CAN SEE AROUND A
COUPLE OF INCHES BY DAYBREAK ACROSS THE SE CWA...LESSENED NEAREST
THE SAG BAY BY LOW LIQUID-SNOW RATIOS AND THE POSSIBILITY (IF WARMER
NAM IS RIGHT) OF A MIX WITH SLEET.
FOR A DISCUSSION ON THE WATCH SITUATION...SEE BELOW.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 457 AM EST SAT DEC 21 2013
AN ACTIVE WEATHER PATTERN ALONG WITH COLD TEMPERATURES CONTINUE
THROUGH THE FORECAST PERIOD WITH A MEAN TROUGH REMAINING IN PLACE
ACROSS CENTRAL CANADA INTO THE GREAT LAKES REGION. IN
ADDITION...UPPER LEVEL DISTURBANCES MOVING THROUGH THE FLOW ALOFT
WILL BRING NUMEROUS CHANCES FOR SNOW SHOWERS...ENHANCED FROM TIME TO
TIME BY THE BIG LAKES. MEANWHILE...THE WELL ADVERTISED SOUTHERN JET
STREAM SYSTEM COULD STILL POTENTIALLY BRING WHAT LOOKS LIKE A
MODERATE AMOUNT OF SNOW TO REGION LATER SATURDAY NIGHT INTO SUNDAY.
THE MAIN LONG TERM FORECAST CONCERNS REVOLVE AROUND SNOW AMOUNTS FOR
SATURDAY NIGHT INTO SUNDAY THEN THE USUAL SUSPECTS...POPS AND
TEMPERATURES FOR THE REMAINDER OF THE FORECAST.
SUNDAY...SOUTHERN BRANCH ENERGY MOVES NORTHWARD ALONG A TIGHTENING
BAROCLINIC ZONE. LATEST MODEL RUNS CONTINUE TO HAVE A MODEST AREA OF
LOW PRESSURE AT THE SURFACE TRACKING ACROSS EITHER NORTHERN OHIO
(MAJORITY OF MODELS) OR SOUTHWEST LOWER MICHIGAN (INCONSISTENT AND
CONTINUED OUTLIER NAM). THERE IS STILL THE POTENTIAL FOR LAKE
ENHANCEMENT OFF OF LAKE HURON ACROSS NORTHEAST LOWER AS A POCKET OF
COLDER AIR (850 MB TEMPS -10 TO -12 C) TRIES TO SYNC UP WITH THE
TAIL END OF DEEP SYNOPTIC MOISTURE. OVERALL...A GENERAL LIGHT TO
MODERATE SNOWFALL IS STILL EXPECTED WITH STORM TOTAL AMOUNTS OF
BETWEEN 4 AND 8 INCHES OF GREASY SNOW WHICH WILL BE COVERED WITH A
WINTER WEATHER ADVISORY FOR ALL COUNTIES OF NORTHERN LOWER MICHIGAN.
WILL STILL HAVE TO BE COGNIZANT OF POSSIBLE SNEAKY LAKE ENHANCEMENT
ADDING TO THE TOTALS ACROSS NORTHEAST LOWER. MEANWHILE...ACROSS
EASTERN UPPER...2 TO 3 INCHES OF ACCUMULATION IS EXPECTED. HIGHS
RANGING FROM THE UPPER TEENS TO MIDDLE 20S...BUT LIKELY FALLING OFF
IN THE AFTERNOON AS COLD AIR ADVECTION KICKS IN.
SUNDAY NIGHT...WRAP AROUND MOISTURE/DEFORMATION ZONE AXIS SITS OVER
THE REGION. THIS WILL LIKELY BRING SOME LIGHT SNOW...WITH ADDITIONAL
ACCUMULATIONS OF ONE TO PERHAPS TWO INCHES. LOWS RANGING FROM THE
COLDER SINGLE DIGITS ABOVE ZERO TO THE MIDDLE TEENS.
MONDAY AND MONDAY NIGHT...A NORTHERN STREAM TROUGH ALONG WITH
ANOTHER SHOT OF ARCTIC AIR (850 MB TEMPS DOWN TO -20 C OR SO) DROPS
DOWN INTO THE REGION BRINGING ADDITIONAL CHANCES FOR MAINLY LIGHT
SNOW. THE FLOW IS RATHER LIGHT OVERALL BUT MAY STILL BE JUST STRONG
ENOUGH TO PRODUCE SOME LAKE EFFECT (GENERALLY OUT OF THE NORTH
NORTHWEST). HOWEVER...AM NOT EXPECTING BIG TIME ACCUMULATIONS WITH
MODEL SOUNDINGS SHOWING INVERSION HEIGHTS OF ONLY AROUND 3000 FEET
OR SO PLUS SNOWFLAKE SIZES WILL LIKELY BE RATHER SMALL. HIGHS MAINLY
IN THE TEENS. LOWS RANGING FROM THE COLDER SINGLE DIGITS TO THE
MIDDLE TEENS.
TUESDAY...PERHAPS SOME LINGERING NORTH NORTHWEST FLOW LAKE EFFECT IN
THE MORNING. OTHERWISE...ARCTIC HIGH PRESSURE PRESSES DOWN FROM THE
NORTH YIELDING VERY COLD TEMPERATURES AND PERHAPS CLEARING SKIES (IF
WE CAN SCOUR OUT THE LIKELY STUBBORN STRATUS). HIGHS ONLY EXPECTED
TO RANGE FROM THE UPPER SINGLE DIGITS (ABOVE ZERO) TO THE MIDDLE
TEENS. LOWS IN THE SINGLE DIGITS ABOVE AND BELOW ZERO AT NIGHT.
WEDNESDAY THROUGH FRIDAY...A PARADE OF SHORT WAVES DROP DOWN THROUGH
THE FLOW. EXTENDED MODELS CONTINUE TO VARY ON THE EXACT TIMING AND
DETAILS SO WILL NOT GET TOO FANCY...AND HAVE GENERAL CHANCES FOR
SNOW SHOWERS. THERE COULD BE SOME LAKE ENHANCEMENT AS WELL FROM TIME
TO TIME...BUT PINNING DOWN THE EXACT FLOW REGIMES IS NEARLY
IMPOSSIBLE THIS FAR OUT. HIGHS IN THE MIDDLE TO UPPER 20S WEDNESDAY
THEN COOLING OFF AGAIN INTO THE UPPER TEENS TO MIDDLE 20S FOR
THURSDAY AND THE MIDDLE TEENS TO AROUND 20 FOR FRIDAY. LOWS IN THE
TEENS WEDNESDAY NIGHT THEN THE SINGLE DIGITS FOR THURSDAY AND FRIDAY
NIGHTS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 628 AM EST SAT DEC 21 2013
A VERY WEAK NORTHERLY LOW LEVEL FLOW WILL DEVELOP THIS MORNING
WITH WEAKER THAN ANTICIPATED DRY AIR ADVECTION. THIS WILL KEEP
IFR/MVFR CIGS IN FOR THE MOST OF THE DAY...IF NOT ALL OF THE DAY
FOR MBL AND POSSIBLY APN/TVC. CAN STILL SEE PLN GOING VFR FOR A
PERIOD TODAY. WINDS VEER BACK TO OUT OF AN EASTERLY DIRECTION
THROUGH TONIGHT AND INCREASE IN SPEED IN ADVANCE OF DEEPENING LOW
PRESSURE THAT WILL WORK INTO THE MID MISSISSIPPI VALLEY BY
DAYBREAK. THICKER AND THICKER MID AND UPPER LEVEL SATURATION WILL
WORK ITS WAY BACK DOWN TO IFR CIGS OVERNIGHT WITH SNOWS DEVELOPING
BY DAYBREAK FOR ALL AIRPORTS EXCEPT MAYBE PLN. CIGS WILL LIKELY
FALL BACK INTO IFR/MVFR EARLIER IN THE EVENING HOWEVER...DUE TO
COOLING OF THE BL. SNOWS WILL LIKELY TURN IFR FROM A VISIBILITY
STANDPOINT.
&&
.MARINE...
ISSUED AT 457 AM EST SAT DEC 21 2013
A LIGHT EASTERLY WINDS REGIME WILL BRIEFLY TURN NORTHERLY OVER MANY
OF THE NEARSHORE WATERS THIS MORNING...BEFORE RETURNING TO EASTERLY
AND INCREASING THROUGH TONIGHT. THIS DUE TO STRENGTHENING LOW
PRESSURE THAT WILL LIFT THROUGH DETROIT. A PERIOD OF ADVISORY LEVEL
WINDS WILL DEVELOP TONIGHT...BEFORE DYING BACK OFF SUNDAY NIGHT INTO
MONDAY WITH THE APPROACH OF HIGHER PRESSURE. THESE LIGHTER WINDS
CONTINUE INTO TUESDAY.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY FROM 1 AM TO 7 PM EST SUNDAY FOR
MIZ016>036-041-042.
LH...SMALL CRAFT ADVISORY FROM 7 PM THIS EVENING TO 7 PM EST SUNDAY
FOR LHZ345>349.
LM...SMALL CRAFT ADVISORY FROM 7 PM THIS EVENING TO 7 PM EST SUNDAY
FOR LMZ323-341-342-344>346.
LS...SMALL CRAFT ADVISORY FROM 7 PM THIS EVENING TO 7 PM EST SUNDAY
FOR LSZ321-322.
&&
$$
UPDATE...BA
SYNOPSIS...AS
SHORT TERM...SD
LONG TERM...AS
AVIATION...SD
MARINE...SD
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
945 AM EST SAT DEC 21 2013
LATEST UPDATE...
UPDATE
DENSE FOG IS BECOMING AN INCREASING CONCERN THIS MORNING MAINLY
ALONG AND SOUTH OF AN EAST-WEST SURFACE BOUNDARY LOCATED JUST
NORTH OF I-94. THERE ARE MANY REPORTS OF VISIBILITY AT OR BELOW
1/4 MILE ALONG AND SOUTH OF THIS BOUNDARY. HRRR GUIDANCE PUSHES
THE BOUNDARY SOUTH OF THE FORECAST AREA BY THIS AFTERNOON WITH
INCREASING WINDS FROM THE NORTHEAST...SO EXPECT DENSE FOG TO BE
LESS OF A CONCERN BY AFTERNOON. WILL HIGHLIGHT THE ONGOING FOG
CONCERN IN AN UPCOMING WSW UPDATE.
RADAR SHOWS THAT PRECIPITATION HAS BEGUN TO OVERSPREAD THE AREA
SOUTHEAST OF A MARSHALL TO MASON LINE. WE ARE A LITTLE CONCERNED
ABOUT AIR TEMPERATURES STAYING SUFFICIENTLY COLD FOR ICE
ACCUMULATION IN THE WARNED AREA. TEMPERATURES AND DEWPOINTS ARE
VERY CLOSE TO FREEZING. A POSITIVE FOR FREEZING RAIN IS COLDER
AND SLIGHTLY DRIER AIR UPSTREAM TO THE NORTHEAST. ALSO SEVERAL
MESONET SITES IN THE AREA ARE REPORTED TEMPERATURES BELOW
FREEZING. CURRENT EXPECTATIONS ARE THAT ICE ACCUMULATION ON
SECONDARY ROADS AND EXPOSED ROAD SURFACES REMAIN A DEFINITE
CONCERN. WILL BE CLOSELY MONITORING TEMPERATURE TRENDS OVER THE
NEXT FEW HOURS.
.SYNOPSIS...
ISSUED AT 329 AM EST SAT DEC 21 2013
A STORM SYSTEM DEVELOPING TO OUR SOUTHWEST WILL BEGIN TO MOVE INTO
THE AREA FROM THE SOUTH TODAY AND CONTINUE TO IMPACT THE AREA
THROUGH THE DAY ON SUNDAY. THIS SYSTEM WILL BRING MAINLY SNOW TO THE
NORTHWEST PORTION OF THE AREA...FREEZING RAIN ACROSS SOUTH CENTRAL
AND SOUTHEAST LOWER MICHIGAN...WITH A WINTRY MIX IN BETWEEN.
COLDER AIR WILL THEN MOVE IN ACROSS THE AREA LATER ON SUNDAY AND
REMAIN IN PLACE MOST OF THE UPCOMING HOLIDAY WEEK. OCCASIONAL
CHANCES OF SNOW SHOWERS CAN BE EXPECTED WITH SOME ACCUMULATIONS
LIKELY...ESPECIALLY CLOSER TO THE LAKESHORE.
&&
.UPDATE...
ISSUED AT 924 AM EST SAT DEC 21 2013
&&
.SHORT TERM...(TODAY THROUGH SUNDAY NIGHT)
ISSUED AT 329 AM EST SAT DEC 21 2013
THE MAIN FOCUS OF THE SHORT TERM IS THE STORM SYSTEM EXPECTED TO
IMPACT THE AREA BEGINNING TODAY AND LASTING THROUGH SUNDAY. WE HAVE
TRANSITIONED THE HEADLINES FROM THE WATCH...TO AN ICE STORM WARNING
ACROSS THE FAR SE CORNER OF THE CWFA. ADVISORIES HAVE BEEN ISSUED
FOR THE REMAINDER OF THE CWFA FOR SNOW ACROSS THE NORTH AND A WINTRY
MIX ACROSS THE MIDDLE SECTION OF THE CWFA. NO MAJOR CHANGES IN THE
FCST HAVE BEEN MADE AS THE CONSENSUS OF THE MODELS IS GENERALLY
CONSISTENT WITH THE PREVIOUS RUNS.
WE WILL NEED TO DEAL WITH SOME FOG ISSUES ACROSS THE SOUTH THIS
MORNING.
THE GREATEST IMPACT OF THE INCOMING STORM SYSTEM LOOKS TO BE THE
THREAT OF RELATIVELY SIGNIFICANT AMOUNTS OF FREEZING RAIN/ICING
EXPECTED ROUGHLY SE OF I-69 LATER TODAY AND INTO THE EARLY OVERNIGHT
HOURS TONIGHT. WE EXPECT RAIN AND OR FREEZING RAIN TO START PUSHING
UP INTO THE SRN COUNTIES TOWARD THE AFTERNOON TODAY. AREAS ALONG AND
SOUTH OF I-94 COULD START OUT BARELY ABOVE FREEZING AT THE ONSET OF
PCPN. WE EXPECT ALL PCPN DOWN ACROSS THE SE CORNER TO TRANSITION TO
FREEZING RAIN AS THE COLD AND SOMEWHAT DRIER NE FLOW WILL BRING
TEMPS DOWN DUE TO ADVECTION AND EVAPORATIVE COOLING.
QPF ACROSS THE SE COUNTIES LOOKS TO BE OVER AN INCH THROUGH THE
EARLY OVERNIGHT HOURS AS THEY BARELY GET UNDER THE NRN PERIPHERY OF
THE BEST MOISTURE AXIS WITH THIS SYSTEM. AN ABOVE FREEZING LAYER
ALOFT IS MAINTAINED MOST OF THE TIME AS THE SFC TEMPS DROP TO AROUND
OR JUST BELOW FREEZING. NOT ALL OF THIS QPF WILL GO INTO THE ICING
EXPECTED DUE TO LATENT HEAT AND RUNOFF PROCESSES. HOWEVER WITH THAT
MUCH QPF...EVEN A PORTION OF IT FREEZING WILL CREATE A GOOD COATING
OF ICE...UP AROUND HALF AN INCH WILL BE LIKELY.
THE TRANSITION IN P-TYPE WILL BE SOMEWHAT TRICKY ACROSS THE CENTRAL
PORTION OF THE CWFA NW OF I-69 TO ROUGHLY M-20. HOWEVER WE EXPECT
THAT FREEZING RAIN AND SLEET TO BE MORE PREVAILING WITH SOME SNOW
POSSIBLE. A SLIGHT ABOVE FREEZING LAYER WILL BE PRESENT WITH THE
LAYER THINNER AND COOLER AS YOU MOVE NW. QPF AMOUNTS WILL BE QUITE A
BIT LESS AS THE MOISTURE AXIS REMAINS SE OF THIS AREA. IT WILL BE
TOUGH TO GET HIGH IMPACT FREEZING RAIN AMOUNTS IN THIS AREA. HOWEVER
ONE THING TO CONSIDER IS THE GLAZE IN PLACE ALREADY FROM THE THU
NIGHT/FRI EVENT.
THE PCPN IN BOTH OF THESE AREAS IS EXPECTED TO LIGHTEN UP
SIGNIFICANTLY BETWEEN 06-12Z SUN AS THE DRY SLOT IS EXPECTED TO MOVE
OVER THESE AREAS. SOME LIGHT PCPN WILL REMAIN...HOWEVER WE COULD
SEE IT TRANSITION TO FZDZ AS THE DGZ BECOMES UNSATURATED.
BY THE TIME PCPN REACHES THE NRN PORTION OF THE CWFA...THE COLUMN
SHOULD BE MAINLY COLD ENOUGH TO SUPPORT MAINLY SNOW. THE SNOW SHOULD
START OUT LIGHT...AND PICK UP LATE TONIGHT/SUN MORNING AS THE BEST
DEFORMATION SLIDES ACROSS THE NRN COUNTIES AND NW OF THE CWFA. SNOW
AMOUNTS ARE GENERALLY EXPECTED TO REMAIN IN THE ADVISORY CATEGORY AS
THE UPPER LOW EJECTING WILL HAVE OPENED UP BY THE TIME IT REACHES
HERE AND THE FGEN IN THE DEFORMATION WILL NOT BE AS STRONG AS TO OUR
SW. ONE THING GOING FOR BETTER SNOW AMOUNTS HERE IS THE FACT THAT
THE DGZ IS EXPECTED TO REMAIN SATURATED AS THE DRY SLOT REMAINS SE
OF THIS AREA.
THE CAVEAT TO ALL OF THIS IS IF THE OUTLIER NAM IS CORRECT...ALL OF
THIS WOULD BE SHIFTING TO THE NW A LITTLE. WE BELIEVE AT THIS TIME
THAT WE HAVE A GOOD CONSENSUS OF THE TRACK OF THE SYSTEM WITH GOOD
RUN TO RUN CONSISTENCY FROM MOST OF THE GLOBAL MODELS AND IT SHOULD
BE WELL SAMPLED BY NOW WITH IT BEING WELL WITHIN THE RAOB NETWORK.
WE WILL SEE A TRANSITION TO SOME LAKE EFFECT SNOW SHOWERS ON SUN
NIGHT AS COLDER AIR COMES IN BEHIND THE SYSTEM. THE FLOW SHOULD BE
NNW WHICH WOULD FAVOR THE IMMEDIATE LAKESHORE FOR BEST SNOW SHOWER
CHANCES. THERE IS SOME DECENT MOISTURE UP THROUGH 15K FEET AND
OVER-LAKE INSTABILITY IS SUFFICIENT.
.LONG TERM...(MONDAY THROUGH FRIDAY)
ISSUED AT 329 AM EST SAT DEC 21 2013
THE UPCOMING CHRISTMAS WEEK WILL BE MORE LIKE WHAT WE HAVE SEEN FOR
MUCH OF DECEMBER: COLDER THAN NORMAL WITH FREQUENT CHANCES FOR SNOW
SHOWERS. THE NORTHERN BRANCH OF THE JET AND ARCTIC AIR WILL DOMINATE
THROUGHOUT THE WEEK... WITH SEVERAL SHORTWAVES AND SFC
TROUGHS/FRONTS SWINGING THROUGH THE GRTLKS RGN. TEMPERATURES ARE
EXPECTED BE BELOW FREEZING ALL WEEK... AND THE COLDEST DAY OF THE
WEEK WILL BE TUESDAY WHEN HIGHS SHOULD STRUGGLE TO REACH 20 BEHIND
THE FIRST NRN STREAM WAVE.
GFS/ECMWF ARE IN GOOD AGREEMENT SHOWING A POTENT SHORTWAVE IMPACTING
THE AREA MONDAY AFTERNOON AND NIGHT. SNOW SHOWERS ARE LIKELY AND
LAKE ENHANCEMENT WILL BE IN PLAY AS THIS FEATURE COMES THROUGH.
HOWEVER CONFIDENCE IN WIND DIRECTION IS LOW SINCE MODELS INDICATE A
WEST TO EAST ORIENTED SFC TROUGH SETTING UP SOMEWHERE ACROSS LWR MI
AND ARE NOT IN GREAT AGREEMENT WITH IT/S LOCATION AND RESULTANT
WINDS. NEVERTHELESS THE TROUGH SHOULD RESULT IN LOCALLY ENHANCED
CONVERGENCE WITH A LARGE PORTION OF THE CWFA SEEING SNOW SHOWERS AND
AT LEAST SOME LIGHT ACCUMULATIONS. IF A WESTERLY FLOW DEVELOPS THEN
AREAS ALONG AND WEST OF HWY 131 COULD SEE SEVERAL INCHES BUT AGAIN
WIND DIRECTION IS VERY QUESTIONABLE AT THIS TIME.
A BRIEF PERIOD OF SHORTWAVE RIDGING MOVES ACROSS FOR TUESDAY
AFTERNOON AND EVENING... THEN SOME WAA/ISENTROPIC LIFT LIGHT SNOW
POSSIBLE ON CHRISTMAS DAY AHEAD OF THE NEXT APPROACHING SHORTWAVE.
THE ECMWF HAS A MUCH STRONGER SHORTWAVE THAN THE GFS FOR THE 26TH
AND WOULD SUGGEST A DECENT ROUND OF ACCUMULATING LAKE ENHANCED SNOW
SHOWERS FOR THURSDAY AND THURSDAY NIGHT.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 706 AM EST SAT DEC 21 2013
WIDESPREAD LIFR CONDITIONS DUE TO LOW CLOUDS AND FOG WILL CONTINUE
TO PLAGUE ALL OF THE TERMINALS TODAY AND TONIGHT. FREEZING RAIN WILL
BREAK OUT AGAIN THIS AFTERNOON... STARTING EARLY THIS AFTERNOON
ALONG THE I-94 CORRIDOR THEN SPREADING NORTH TO THE I-96 CORRIDOR
BY LATE AFTERNOON WHERE SOME SLEET AND SNOW MAY MIX WITH THE FREEZING
RAIN AT THE ONSET. MKG SHOULD TEND TO BE MOSTLY SNOW AND SLEET AS
PRECIP DEVELOPS THERE EARLY THIS EVENING.
THE INTENSITY OF THE FREEZING RAIN/ICING IS EXPECTED TO BE
HEAVIEST DURING THE EVENING HOURS THEN DIMINISH AFTER 06Z TONIGHT.
MKG SHOULD BE THE EXCEPTION TO THIS... WHERE SNOW WILL CONTINUE
OVERNIGHT.
&&
.MARINE...
ISSUED AT 534 PM EST FRI DEC 20 2013
NORTHEAST FLOW WILL CONTINUE INTO SATURDAY NIGHT. THIS OFFSHORE FLOW
WILL HELP KEEP WAVES LOWER. HOWEVER AS WINDS PIVOT TO THE NORTH
NORTHWEST LATE SATURDAY NIGHT/EARLY SUNDAY MORNING WAVES WILL BUILD
AND WE WILL LIKELY NEED A SMALL CRAFT ADVISORY BY THEN.
&&
.HYDROLOGY...
ISSUED AT 325 PM EST FRI DEC 20 2013
THE FORECAST TREND IS TOWARDS LESS QPF OVER THE WEEKEND AS THE
TRACK OF THE LOW LOOKS TO STAY FURTHER SOUTH AND EAST OF THE RIVER
BASINS IN SOUTHWEST LOWER MICHIGAN. TOTAL QPF IS NOW EXPECTED TO
BE LESS THAN AN INCH FOR THE HEADWATERS OF THE GRAND AND ST.
JOSEPH BASINS.
SHARP RISES ARE STILL POSSIBLE AT THE JACKSON FORECAST POINT ON
THE GRAND RIVER AND WE WILL HAVE TO WATCH THE MODEL TRENDS CLOSELY
TONIGHT AND THE ACTUAL STORM DEVELOPMENT ON SATURDAY. SNOW MELT
COULD ALSO CONTRIBUTE TO RISES ACROSS THE ST. JOSEPH AND KALAMAZOO
BASINS BEFORE THE ARCTIC AIR RETURNS ON MONDAY...WITH ICE
REFORMING ON THE RIVERS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO NOON EST
SUNDAY FOR MIZ051-052-056>059-064-065-071-072.
ICE STORM WARNING FROM 1 PM THIS AFTERNOON TO 7 AM EST SUNDAY
FOR MIZ066-067-073-074.
WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 7 PM EST
SUNDAY FOR MIZ037>040-043>046-050.
LM...NONE.
&&
$$
UPDATE...TJT
SYNOPSIS...NJJ
SHORT TERM...NJJ
LONG TERM...MEADE
AVIATION...MEADE
HYDROLOGY...OSTUNO
MARINE...JK
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
643 AM EST SAT DEC 21 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 457 AM EST SAT DEC 21 2013
SW FLOW ALOFT BTWN UPPER LOW OVER HUDSON BAY AND STRONG SOUTHERN
STREAM DISTURBANCE OVER NEW MEXICO. THROUGH TONIGHT...MAIN ISSUES
ARE TIED TO LAKE EFFECT. SOUTHERN STREAM WAVE LIFTS TOWARD UPPER GREAT
LAKES LATER TONIGHT...THOUGH IT APPEARS MAJORITY OF WIDESPREAD SNOW
WITH THE DEVELOPING LOW PRESSURE SYSTEM WILL REMAIN JUST SOUTH OF CWA
UNTIL DAYBREAK ON SUNDAY.
EMBEDDED SHORTWAVES/PV ANOMALIES IN FLOW ALOFT HELPING TO SUSTAIN
LGT SNOW/FLURRIES OVER CWA EARLY THIS MORNING. ALSO A BAND OF
ENHANCED LK EFFECT MAINLY OVER SCNTRL AND SOUTHEAST PORTIONS OF LK
SUPERIOR. RAP...WHICH DOES HAVE DECENT HANDLE ON BACK EDGE OF LGT
SNOW CURRENTLY...INDICATES MID-LEVEL MOISTURE/UVM EXITS EAST HALF
OF CWA THROUGH AROUND DAYBREAK THIS MORNING SO WOULD EXPECT LGT SNOW
TO END FOR A TIME. AT THE LEAST THE CLOUDS WILL CONTINUE TO HOLD UP
TEMPS THIS MORNING MAINLY IN THE TEENS. MILD FOR SURE COMPARED TO
THE RECENT CHILL UPR LAKES HAS EXPERIENCED. CURRENTLY THERE IS A SFC
TROUGH ACROSS THE AREA EXTENDING TO THE NW OF SFC LOW NEAR DETROIT.
EXPECT TROUGHING TO PERSIST THROUGH MUCH OF THE DAY WHILE GRADUALLY
GETTING PUSHED TO THE SOUTH AND EAST BY THIS AFTN AS HIGH PRESSURE
OVR SASKATCHEWAN AND MANITOBA TRIES TO RIDGE ACROSS LK SUPERIOR
REGION. THE MAIN IMPACT THIS HAS IS ON WIND FIELDS AND ASSOCIATED
LAKE EFFECT AS THERE IS ENOUGH INSTABILITY WITH INVERSIONS UP TO
5-7KFT AND TEMPS AT INVERSION TOP AROUND -13C WHILE WATER TEMPS ARE
AROUND +3C. SOUNDINGS AT P59/CMX AND STDM4 INDICATE DECENT
SUBSIDENCE ABOVE MOIST LAKE EFFECT LAYER AND ALSO NOT AS MUCH LIFT
WITHIN THE DGZ. IF CONVERGENCE CAN PERSIST OVER THE KEWEENAW
TODAY...THEN THERE IS AN OPPORTUNITY FOR ADVY LEVEL SNOW AMOUNTS.
CONFIDENCE IS LOW ON THIS POTENTIAL AND EVEN LOWER ON EXACTLY WHERE
THAT WOULD OCCUR. FOLLOWED GEM-REGIONAL THROUGH TODAY FOR WINDS
ALONG WITH NAM AND LOCAL-WRF MODEL BASED ON RAP BOUNDARY CONDITIONS.
THIS BLEND ESSENTIALLY HANGS UP MAIN CONVERGENCE AREA OVER NORTHERN
KEWEENAW THEN EVENTUALLY DRAWS IT SOUTH ACROSS THE PENINSULA THIS
AFTN AS THE HIGH BUILDS TOWARD LK SUPERIOR. SINCE INSTABILITY IS NOT
EXTREME OR OVER THE TOP BY ANY MEANS...FCST SNOW AMOUNTS FROM 2-4
INCHES...GREATEST NEAR MOHAWK/EAGLE RIVER/COPPER HARBOR. DESPITE
MODELS NOT SHOWING MUCH OCCURRING FOR OTHER AREAS WHERE FLOW IS
ONSHORE NEAR LK SUPERIOR...WENT WITH PERSISTENCE AND KEPT MENTION OF
SNOW OVER FAR WESTERN UPR MICHIGAN AND ALSO IN NCNTRL UPR MICHIGAN.
ANY AMOUNTS FOR THESE AREAS TODAY WILL JUST A DUSTING OF LESS THAN 1
INCH.
MINOR ISSUE FOR TODAY IS SKY COVER AND TEMPS. MODELS STRUGGLING WITH
EVENTUAL EVOLUTION OF LOW MVFR CLOUDS FM LK SUPERIOR BACK INTO CNTRL
MINNESOTA. NAM/RAP/GEM-REGIONAL SHOW THESE CLOUDS TO START BUT SEEM
TOO QUICK TO GET RID OF THEM OVER ALL BUT WESTERN CWA BY LATER
MORNING. WE WILL SEE ON THIS. IF MORE SUN OCCURS...MAX TEMPS MAY
PUSH WELL INTO THE MID-UPR 20S CNTRL. BASED ON CURRENT SATELLITE/OBS
TRENDS AND WITH SUN ANGLE ABOUT AS LOW AS IT GETS...WILL KEEP SKIES
MOSTLY CLOUDY FOR TODAY. LATER TODAY WILL BE A MOOT POINT AS
INCREASING NE WINDS SHOULD RESULT IN EXPANSION OF CLOUDS OFF LK
SUPERIOR.
SOUTHERN STREAM WAVE/LOW PRESSURE SYSTEM AFFECTS WILL BE KNOCKING ON
THE DOOR OF UPR MICHIGAN SO TO SPEAK LATER TONIGHT. NAM/GFS/ECMWF
LOOKED SIMILAR WITH PLACEMENT OF H5 TROUGH/PRIMARY PV ANAMOLY/H85
AND SFC LOWS. GEM WAS FARTHER NORTH WITH H85 LOW. SEEMED THAT ECMWF
WAS A NICE MIDDLE GROUND BTWN FARTHER SOUTH NAM/GFS WITH ADVANCING
WIDESPREAD SNOW AND MORE AGRESSIVE GEM. BROUGHT LIKELY POPS FOR
SYNOPTIC SNOW INTO FAR SCNTRL BY 09Z SUNDAY. OTHER IMPACT WILL BE
INCREASING FAVORABLE LAKE EFFECT OVER FAR WEST/KEWEENAW AND NCNTRL
CWA. NOT EXPECTING A LOT OF SNOW AS ANY LARGE SCALE FORCING IS
MINIMAL THROUGH 12Z...BUT THERE IS ENOUGH EVIDENCE IN FCST SOUNDINGS
THAT LAKE EFFECT WILL BE DEVELOPED ENOUGH TO RESULT IN LIKELY POPS
WITH MINOR SNOW AMOUNTS. SETUP BECOMES MUCH MORE FAVORABLE FOR
SIGNIFICANT LAKE ENHANCEMENT FOR SUNDAY AND BEYOND. BTWN THE LAKE
EFFECT MOISTURE/SNOW AND MID-HIGH CLOUDS ARRIVING FROM THE
SOUTH...EXPECT TEMPS TONIGHT TO STAY IN THE TEENS AGAIN.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 457 AM EST SAT DEC 21 2013
HAVE OPTED TO ISSUE A WINTER STORM WATCH FOR THE TERRAIN/LAKE
ENHANCED AREAS OF MARQUETTE/BARAGA COUNTIES AS WELL AS GOGEBIC AND
ONTONAGON COUNTIES FOR SUNDAY AND MONDAY. LONG DURATION LAKE
ENHANCED/LAKE EFFECT SNOW EPISODE LOOKING MORE POSSIBLE NOW AS THE
MODELS ARE STARTING TO COME INTO BETTER AGREEMENT INTO A MAIN LOW
TRACK THROUGH SOUTHERN MI ON SUNDAY. HOWEVER...THE COMPLEX
INTERACTION BETWEEN THE SOUTHERN STREAM ENERGY MOVING THROUGH THE
LOWER LAKES AND THE NORTHERN STREAM TROUGH MOVING INTO THE UPPER
MIDWEST MAKES THIS FORECAST CONFIDENCE STILL SOMEWHAT BELOW AVERAGE.
ONTO THE DETAILS...AS SAID ABOVE THE NWP SUITE HAVE COME INTO BETTER
AGREEMENT WITH THE MAIN LOW MOVING THROUGH SOUTHERN LOWER MICHIGAN
WITH THE SOUTHERN STREAM IMPULSE MOVING OUT OF THE PLAINS. EXPECT
SYNOPTIC MOISTURE AND LIFT TO GLANCE BY THE SOUTHEAST FORECAST AREA
SUNDAY MORNING INTO EARLY AFTERNOON AS THE COMMA HEAD/DEFORMATION
ZONE PCPN MOVES THROUGH. THIS TRACK WILL ALLOW FOR 1000-850MB WINDS
TO TURN NE AND SHOULD ALLOW FOR LAKE ENHANCEMENT TO ALSO DEVELOP IN
MARQUETTE/BARAGA COUNTIES AS WELL AS THE FAR WEST NEAR IRONWOOD.
CONSENSUS QPF FROM THE NWP SUGGEST ABOUT 0.20-0.30 INCH OF QPF NEAR
LAKE MICHIGAN AND FAR EAST ON SUNDAY...WITH MUCH LESSER AMOUNTS WELL
INLAND AWAY FROM FROM LAKE SUPERIOR. THIS ALSO SEEMS REASONABLE
GIVEN THAT 700MB MIXING RATIOS REMAIN AROUND 2 G/KG THROUGH EARLY
AFTERNOON. GIVEN THAT SOME OF THE LIFT WILL BE IN THE DGZ AREA
ACROSS THE SOUTH DURING THE DAY...WE SHOULD SEE SNOW RATIOS ACROSS
THE FAR SOUTHEAST AROUND 15-17:1 DURING THE DAY WHICH WOULD EQUATE
TO 3-5 INCHES OF SNOW BY EVENING. MOST LIKELY AN ADVISORY WILL BE
NEEDED IN THIS AREA ON SUNDAY...BUT WILL HOLD OFF SINCE THIS WILL BE
GENERALLY A 3RD PERIOD ADVY.
AS FOR AREAS CLOSER TO LAKE SUPERIOR...ALL OF THE NWP GUIDANCE SHOW
PBL WINDS STAYING NELY THROUGH THE DAY WHICH SHOULD ALLOW FOR
TERRAIN ENHANCED SNOW TO COMMENCE IN THE NE FLOW FAVORED AREAS
DESPITE THE RELATIVELY WEAK SYNOPTIC LIFT. WITH THE BEST LIFT BEING
CONFINED TO GENERALLY BELOW THE DGZ...EXPECT SNOW RATIOS BE BE
FAIRLY LOW WITH ONLY AROUND 13:1. WILL GENERALLY GO WITH 4 OR 5
INCHES AT MOST IN THESE AREAS...BUT GIVEN THE STRONG AND DEEP NE
FLOW...WOULD NOT BE SHOCKED IF QPF AND THUS SNOWFALL IS MORE ON
SUNDAY.
THEN ON SUNDAY NIGHT...DIFFERENCE START TO DEVELOP WITH THE MODELS
REGARDING THE EVOLUTION OF THE NORTHERN STREAM UPPER TROUGH. THE NAM
IS CERTAINLY THE MOST AGGRESSIVE IN CLOSING OFF THE LOW AND
SETTLING OVER THE UPPER GREAT LAKES...WHICH ALLOW FOR A STRONG
INVERTED TROUGH TO HANG BACK ACROSS THE CENTRAL GREAT LAKES THROUGH
MONDAY. MEANWHILE...THE GFS GENERALLY KEEPS THE UPPER TROUGH OPEN
AND MOVES IN THROUGH THE AREA BY MONDAY AFTERNOON. THE LATEST 00Z
ECMWF IS INTERESTING AS IT ALSO ATTEMPT TO CLOSE OFF THE LOW SUN
NIGHT BUT IS NOT NEARLY AS DEEP AS THE NAM FORECASTS.
NONETHELESS...THE ECMWF ALSO SUGGESTS THAT THERE WILL BE SOME TYPE
OF INVERTED TROUGH EXTENDING BACK INTO THE AREA THROUGH MONDAY AND
OUR LOCALLY PRODUCE ARW-WRF USING THE GFS AS BOUNDARY CONDITIONS
ALSO SUGGEST THAT THERE WILL BE A INVERTED TROUGH HANGING BACK
THROUGH MONDAY. AS SUCH...DO NOT THINK THE PBL WINDS WILL SHIFT TO
N-NW AS FAST AS THE GFS AND ECMWF SUGGEST. IN FACT...THE CURRENT
THINKING IS THAT THE WINDS WILL STAY NORTHERLY OR PERHAPS A LITTLE
EAST OF NORTH THROUGH MONDAY WITH THIS TROUGH STAYING SOUTH OF THE
AREA. WITH ALL OF THIS SAID...THE EXPECTATION IS THAT THE SNOW WILL
TRANSITION TO MORE LAKE ENHANCED VARIETY AND PERSIST RIGHT THROUGH
MONDAY BEFORE THE UPPER TROUGH SWINGS THROUGH AND ALLOWS THE WIND TO
GRADUALLY SHIFT TO THE N-NW BY MON EVENING. AS SUCH...EXPECT
MODERATE TO LOCALLY HEAVY SNOW TO CONTINUE IN MQT/BARAGA COUNTIES AS
WELL AS GOGEBIC COUNTY THROUGH THE NIGHT SUNDAY INTO MONDAY. THE
BEST LIFT RAPIDLY BECOMING ENTRENCHED IN THE DGZ SUNDAY EVENING AS
THE UPPER TEMPS DROP...EXPECT THE SNOW TO BECOME MUCH MORE FLUFFY
BUT ALSO ACCUMULATE MUCH FASTER WITH RATIOS CLOSE TO 25:1 BY MON
MORNING. SOME AREAS IN THE WATCH AREA COULD SEE ANOTHER 8-12 INCHES
OF SNOW SUN NIGHT INTO MONDAY.
INTERESTINGLY...THERE ARE SEVERAL VERY GOOD CIPS ANALOG EVENTS FOR
THIS SYSTEM. THEY ALL GENERALLY SHOW THE WATCH AREA SEEING
SIGNIFICANT 72 HOUR SNOWFALL. NOT SURE IF WE WILL SEE ANY LONGER
PERIOD OF HEAVY SNOWFALL...RATHER I AM THINKING THAT IT WILL BE
GENERALLY A PERSISTENT SNOWFALL FOR 24-36 HOURS WHICH WILL ALLOW
WARNING CRITERIA TO BE REACHED. EVEN MORE INTERESTING...DESPITE THE
FACT THAT GOGEBIC COUNTY WILL BE FURTHEST REMOVED FROM THE
SYSTEM...THE CURRENT NWP AND ALSO THE CIPS GUIDANCE SUGGEST THAT
THIS AREA COULD SEE THE MOST SNOWFALL OUT OF THIS EVENT. WE WILL
SEE...
ANY REMAINING LES SHOULD END RAPIDLY MON NIGHT/TUE MORNING AS THE
HIGH PRES RIDGE BUILDS ACROSS THE FORECAST AREA. STILL LOOKS QUITE
COLD TUE MORNING ACROSS THE WEST WITH LIGHT WINDS/CLEAR SKIES. TEMPS
10-20 BELOW NOT OUT OF THE QUESTION IN THE NORMALLY COLDER SPOTS.
THE ECMWF AND GEM ARE IN GOOD AGREEMENT IN LIGHT OVERRUNNING/WARM
ADVECTION SNOW CHRISTMAS EVE NIGHT INTO CHRISTMAS DAY ACROSS THE
ENTIRE FORECAST AREA. SOME HINTS THAT THERE MIGHT BE SOME LAKE
ENHANCEMENT OFF OF LAKE MICHIGAN TUESDAY NIGHT AND HAVE OPTED TO
CONTINUE LIKELY POPS ACROSS THE EASTERN PART OF THE FORECAST AREA
TUE NIGHT INTO CHRISTMAS DAY. SOME DIFFERENCES EMERGE THU INTO
FRIDAY REGARDING THE EVOLUTION AND THE TROUGH WITH THE ECMWF BEING
DEEPER AND FURTHER SOUTH COMPARED TO THE GFS. REGARDLESS...SENSIBLE
WEATHER SHOULD GENERALLY THE SAME WITH EITHER MODEL WITH LES IN THE
NW FAVORED SNOWBELTS CHRISTMAS NIGHT INTO THU NIGHT BEFORE
DIMINISHING ON FRIDAY AS HIGH PRES BUILDS OVERHEAD. TEMPS STILL LOOK
BELOW NORMAL THROUGH THE EXTENDED WITH 850MB TEMPS -20 TO -25C WED
NIGHT/THU WARMING TO -15 TO -20C BY FRIDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 640 AM EST SAT DEC 21 2013
WITH ABUNDANT LOW LEVEL MOISTURE AND LIGHT WINDS ACROSS THE
REGION...MAINLY MVFR CIGS ARE EXPECTED THROUGH THE FCST PERIOD AT
CMX AND IWD. EXPECT LAKE EFFECT SNOW SHOWERS TO DEVELOP AT CMX LATER
TODAY AND THESE WILL CONTINUE THROUGH TONIGHT. IFR VSBY IS EXPECTED
IN THE SNOW AND ALSO DUE TO BLSN WITH GUSTY EAST WINDS DEVELOPING.
SNOW SHOWERS WILL BEGIN TO AFFECT IWD LATE TONIGHT AS WINDS BECOME
MORE NORTHEAST. WEAK DOWNSLOPE WESTERLY FLOW AT SAW WILL FAVOR VFR
CONDITIONS UNTIL LATE THIS AFTERNOON WHEN WINDS VEER TO THE NNE AND
UPSLOPE FLOW LEADS TO MVFR CIGS AND SOME LIGHT SNOW SHOWERS. WINDS
BECOMING MORE EASTERLY WILL SCATTER OUT THE LOW CLOUDS AT SAW LATE
TONIGHT. WIDESPREAD SNOW IS EXPECTED TO IMPACT ALL TERMINALS ON
SUNDAY AS A LOW PRESSURE SYSTEM SLIDES ACROSS THE CENTRAL GREAT
LAKES REGION. HEAVIEST SNOW WILL OCCUR AT IWD WITH UPSLOPE NORTHEAST
WINDS PROVIDING ADDITIONAL SUPPORT FOR SNOW OFF LK SUPERIOR.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 457 AM EST SAT DEC 21 2013
LIGHT WINDS TODAY WITH TROUGH OVER THE LAKE THEN AS THE TROUGH SINKS
SOUTH TONIGHT...EXPECT STRONG AND GUSTY NORTHEAST WINDS TO 30 KTS
OVER MUCH OF LAKE SUPERIOR INTO SUNDAY...FURTHER STRENGTHENED BY LOW
PRESSURE LIFTING ACROSS LOWER MICHIGAN. COULD BE GALE GUSTS OVER
THE WEST WITH CHANNELING BETWEEN MINNESOTA SHORELINE AND KEWEENAW
PENINSULA. DURING THIS PERIOD OF STRONGER WINDS THERE WILL BE
FREEZING SPRAY. EXPECT THE LOW TO LINGER A SURFACE TROUGH OVER THE
UPPER GREAT LAKES THROUGH MONDAY AND KEEP WINDS UP TO 25 KTS. HIGH
PRESSURE WILL CROSS THE UPPER GREAT LAKES ON MONDAY NIGHT...WHILE A
LOW PRESSURE SYSTEM BEGINS TO TAKE SHAPE IN THE CANADIAN PRAIRIES.
THIS LOW WILL LEAD TO INCREASING SOUTHERLY WINDS ACROSS LAKE
SUPERIOR ON TUESDAY. WHEN THE LOW MOVES THROUGH THE REGION ON
WEDNESDAY...WINDS WILL BECOME WESTERLY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER STORM WATCH FROM SUNDAY MORNING THROUGH MONDAY EVENING
FOR MIZ002-004-005-009.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLA
LONG TERM...MRD
AVIATION...JLA
MARINE...JLA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
459 AM EST SAT DEC 21 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 457 AM EST SAT DEC 21 2013
SW FLOW ALOFT BTWN UPPER LOW OVER HUDSON BAY AND STRONG SOUTHERN
STREAM DISTURBANCE OVER NEW MEXICO. THROUGH TONIGHT...MAIN ISSUES
ARE TIED TO LAKE EFFECT. SOUTHERN STREAM WAVE LIFTS TOWARD UPPER GREAT
LAKES LATER TONIGHT...THOUGH IT APPEARS MAJORITY OF WIDESPREAD SNOW
WITH THE DEVELOPING LOW PRESSURE SYSTEM WILL REMAIN JUST SOUTH OF CWA
UNTIL DAYBREAK ON SUNDAY.
EMBEDDED SHORTWAVES/PV ANOMALIES IN FLOW ALOFT HELPING TO SUSTAIN
LGT SNOW/FLURRIES OVER CWA EARLY THIS MORNING. ALSO A BAND OF
ENHANCED LK EFFECT MAINLY OVER SCNTRL AND SOUTHEAST PORTIONS OF LK
SUPERIOR. RAP...WHICH DOES HAVE DECENT HANDLE ON BACK EDGE OF LGT
SNOW CURRENTLY...INDICATES MID-LEVEL MOISTURE/UVM EXITS EAST HALF
OF CWA THROUGH AROUND DAYBREAK THIS MORNING SO WOULD EXPECT LGT SNOW
TO END FOR A TIME. AT THE LEAST THE CLOUDS WILL CONTINUE TO HOLD UP
TEMPS THIS MORNING MAINLY IN THE TEENS. MILD FOR SURE COMPARED TO
THE RECENT CHILL UPR LAKES HAS EXPERIENCED. CURRENTLY THERE IS A SFC
TROUGH ACROSS THE AREA EXTENDING TO THE NW OF SFC LOW NEAR DETROIT.
EXPECT TROUGHING TO PERSIST THROUGH MUCH OF THE DAY WHILE GRADUALLY
GETTING PUSHED TO THE SOUTH AND EAST BY THIS AFTN AS HIGH PRESSURE
OVR SASKATCHEWAN AND MANITOBA TRIES TO RIDGE ACROSS LK SUPERIOR
REGION. THE MAIN IMPACT THIS HAS IS ON WIND FIELDS AND ASSOCIATED
LAKE EFFECT AS THERE IS ENOUGH INSTABILITY WITH INVERSIONS UP TO
5-7KFT AND TEMPS AT INVERSION TOP AROUND -13C WHILE WATER TEMPS ARE
AROUND +3C. SOUNDINGS AT P59/CMX AND STDM4 INDICATE DECENT
SUBSIDENCE ABOVE MOIST LAKE EFFECT LAYER AND ALSO NOT AS MUCH LIFT
WITHIN THE DGZ. IF CONVERGENCE CAN PERSIST OVER THE KEWEENAW
TODAY...THEN THERE IS AN OPPORTUNITY FOR ADVY LEVEL SNOW AMOUNTS.
CONFIDENCE IS LOW ON THIS POTENTIAL AND EVEN LOWER ON EXACTLY WHERE
THAT WOULD OCCUR. FOLLOWED GEM-REGIONAL THROUGH TODAY FOR WINDS
ALONG WITH NAM AND LOCAL-WRF MODEL BASED ON RAP BOUNDARY CONDITIONS.
THIS BLEND ESSENTIALLY HANGS UP MAIN CONVERGENCE AREA OVER NORTHERN
KEWEENAW THEN EVENTUALLY DRAWS IT SOUTH ACROSS THE PENINSULA THIS
AFTN AS THE HIGH BUILDS TOWARD LK SUPERIOR. SINCE INSTABILITY IS NOT
EXTREME OR OVER THE TOP BY ANY MEANS...FCST SNOW AMOUNTS FROM 2-4
INCHES...GREATEST NEAR MOHAWK/EAGLE RIVER/COPPER HARBOR. DESPITE
MODELS NOT SHOWING MUCH OCCURRING FOR OTHER AREAS WHERE FLOW IS
ONSHORE NEAR LK SUPERIOR...WENT WITH PERSISTENCE AND KEPT MENTION OF
SNOW OVER FAR WESTERN UPR MICHIGAN AND ALSO IN NCNTRL UPR MICHIGAN.
ANY AMOUNTS FOR THESE AREAS TODAY WILL JUST A DUSTING OF LESS THAN 1
INCH.
MINOR ISSUE FOR TODAY IS SKY COVER AND TEMPS. MODELS STRUGGLING WITH
EVENTUAL EVOLUTION OF LOW MVFR CLOUDS FM LK SUPERIOR BACK INTO CNTRL
MINNESOTA. NAM/RAP/GEM-REGIONAL SHOW THESE CLOUDS TO START BUT SEEM
TOO QUICK TO GET RID OF THEM OVER ALL BUT WESTERN CWA BY LATER
MORNING. WE WILL SEE ON THIS. IF MORE SUN OCCURS...MAX TEMPS MAY
PUSH WELL INTO THE MID-UPR 20S CNTRL. BASED ON CURRENT SATELLITE/OBS
TRENDS AND WITH SUN ANGLE ABOUT AS LOW AS IT GETS...WILL KEEP SKIES
MOSTLY CLOUDY FOR TODAY. LATER TODAY WILL BE A MOOT POINT AS
INCREASING NE WINDS SHOULD RESULT IN EXPANSION OF CLOUDS OFF LK
SUPERIOR.
SOUTHERN STREAM WAVE/LOW PRESSURE SYSTEM AFFECTS WILL BE KNOCKING ON
THE DOOR OF UPR MICHIGAN SO TO SPEAK LATER TONIGHT. NAM/GFS/ECMWF
LOOKED SIMILAR WITH PLACEMENT OF H5 TROUGH/PRIMARY PV ANAMOLY/H85
AND SFC LOWS. GEM WAS FARTHER NORTH WITH H85 LOW. SEEMED THAT ECMWF
WAS A NICE MIDDLE GROUND BTWN FARTHER SOUTH NAM/GFS WITH ADVANCING
WIDESPREAD SNOW AND MORE AGRESSIVE GEM. BROUGHT LIKELY POPS FOR
SYNOPTIC SNOW INTO FAR SCNTRL BY 09Z SUNDAY. OTHER IMPACT WILL BE
INCREASING FAVORABLE LAKE EFFECT OVER FAR WEST/KEWEENAW AND NCNTRL
CWA. NOT EXPECTING A LOT OF SNOW AS ANY LARGE SCALE FORCING IS
MINIMAL THROUGH 12Z...BUT THERE IS ENOUGH EVIDENCE IN FCST SOUNDINGS
THAT LAKE EFFECT WILL BE DEVELOPED ENOUGH TO RESULT IN LIKELY POPS
WITH MINOR SNOW AMOUNTS. SETUP BECOMES MUCH MORE FAVORABLE FOR
SIGNIFICANT LAKE ENHANCEMENT FOR SUNDAY AND BEYOND. BTWN THE LAKE
EFFECT MOISTURE/SNOW AND MID-HIGH CLOUDS ARRIVING FROM THE
SOUTH...EXPECT TEMPS TONIGHT TO STAY IN THE TEENS AGAIN.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 457 AM EST SAT DEC 21 2013
HAVE OPTED TO ISSUE A WINTER STORM WATCH FOR THE TERRAIN/LAKE
ENHANCED AREAS OF MARQUETTE/BARAGA COUNTIES AS WELL AS GOGEBIC AND
ONTONAGON COUNTIES FOR SUNDAY AND MONDAY. LONG DURATION LAKE
ENHANCED/LAKE EFFECT SNOW EPISODE LOOKING MORE POSSIBLE NOW AS THE
MODELS ARE STARTING TO COME INTO BETTER AGREEMENT INTO A MAIN LOW
TRACK THROUGH SOUTHERN MI ON SUNDAY. HOWEVER...THE COMPLEX
INTERACTION BETWEEN THE SOUTHERN STREAM ENERGY MOVING THROUGH THE
LOWER LAKES AND THE NORTHERN STREAM TROUGH MOVING INTO THE UPPER
MIDWEST MAKES THIS FORECAST CONFIDENCE STILL SOMEWHAT BELOW AVERAGE.
ONTO THE DETAILS...AS SAID ABOVE THE NWP SUITE HAVE COME INTO BETTER
AGREEMENT WITH THE MAIN LOW MOVING THROUGH SOUTHERN LOWER MICHIGAN
WITH THE SOUTHERN STREAM IMPULSE MOVING OUT OF THE PLAINS. EXPECT
SYNOPTIC MOISTURE AND LIFT TO GLANCE BY THE SOUTHEAST FORECAST AREA
SUNDAY MORNING INTO EARLY AFTERNOON AS THE COMMA HEAD/DEFORMATION
ZONE PCPN MOVES THROUGH. THIS TRACK WILL ALLOW FOR 1000-850MB WINDS
TO TURN NE AND SHOULD ALLOW FOR LAKE ENHANCEMENT TO ALSO DEVELOP IN
MARQUETTE/BARAGA COUNTIES AS WELL AS THE FAR WEST NEAR IRONWOOD.
CONSENSUS QPF FROM THE NWP SUGGEST ABOUT 0.20-0.30 INCH OF QPF NEAR
LAKE MICHIGAN AND FAR EAST ON SUNDAY...WITH MUCH LESSER AMOUNTS WELL
INLAND AWAY FROM FROM LAKE SUPERIOR. THIS ALSO SEEMS REASONABLE
GIVEN THAT 700MB MIXING RATIOS REMAIN AROUND 2 G/KG THROUGH EARLY
AFTERNOON. GIVEN THAT SOME OF THE LIFT WILL BE IN THE DGZ AREA
ACROSS THE SOUTH DURING THE DAY...WE SHOULD SEE SNOW RATIOS ACROSS
THE FAR SOUTHEAST AROUND 15-17:1 DURING THE DAY WHICH WOULD EQUATE
TO 3-5 INCHES OF SNOW BY EVENING. MOST LIKELY AN ADVISORY WILL BE
NEEDED IN THIS AREA ON SUNDAY...BUT WILL HOLD OFF SINCE THIS WILL BE
GENERALLY A 3RD PERIOD ADVY.
AS FOR AREAS CLOSER TO LAKE SUPERIOR...ALL OF THE NWP GUIDANCE SHOW
PBL WINDS STAYING NELY THROUGH THE DAY WHICH SHOULD ALLOW FOR
TERRAIN ENHANCED SNOW TO COMMENCE IN THE NE FLOW FAVORED AREAS
DESPITE THE RELATIVELY WEAK SYNOPTIC LIFT. WITH THE BEST LIFT BEING
CONFINED TO GENERALLY BELOW THE DGZ...EXPECT SNOW RATIOS BE BE
FAIRLY LOW WITH ONLY AROUND 13:1. WILL GENERALLY GO WITH 4 OR 5
INCHES AT MOST IN THESE AREAS...BUT GIVEN THE STRONG AND DEEP NE
FLOW...WOULD NOT BE SHOCKED IF QPF AND THUS SNOWFALL IS MORE ON
SUNDAY.
THEN ON SUNDAY NIGHT...DIFFERENCE START TO DEVELOP WITH THE MODELS
REGARDING THE EVOLUTION OF THE NORTHERN STREAM UPPER TROUGH. THE NAM
IS CERTAINLY THE MOST AGGRESSIVE IN CLOSING OFF THE LOW AND
SETTLING OVER THE UPPER GREAT LAKES...WHICH ALLOW FOR A STRONG
INVERTED TROUGH TO HANG BACK ACROSS THE CENTRAL GREAT LAKES THROUGH
MONDAY. MEANWHILE...THE GFS GENERALLY KEEPS THE UPPER TROUGH OPEN
AND MOVES IN THROUGH THE AREA BY MONDAY AFTERNOON. THE LATEST 00Z
ECMWF IS INTERESTING AS IT ALSO ATTEMPT TO CLOSE OFF THE LOW SUN
NIGHT BUT IS NOT NEARLY AS DEEP AS THE NAM FORECASTS.
NONETHELESS...THE ECMWF ALSO SUGGESTS THAT THERE WILL BE SOME TYPE
OF INVERTED TROUGH EXTENDING BACK INTO THE AREA THROUGH MONDAY AND
OUR LOCALLY PRODUCE ARW-WRF USING THE GFS AS BOUNDARY CONDITIONS
ALSO SUGGEST THAT THERE WILL BE A INVERTED TROUGH HANGING BACK
THROUGH MONDAY. AS SUCH...DO NOT THINK THE PBL WINDS WILL SHIFT TO
N-NW AS FAST AS THE GFS AND ECMWF SUGGEST. IN FACT...THE CURRENT
THINKING IS THAT THE WINDS WILL STAY NORTHERLY OR PERHAPS A LITTLE
EAST OF NORTH THROUGH MONDAY WITH THIS TROUGH STAYING SOUTH OF THE
AREA. WITH ALL OF THIS SAID...THE EXPECTATION IS THAT THE SNOW WILL
TRANSITION TO MORE LAKE ENHANCED VARIETY AND PERSIST RIGHT THROUGH
MONDAY BEFORE THE UPPER TROUGH SWINGS THROUGH AND ALLOWS THE WIND TO
GRADUALLY SHIFT TO THE N-NW BY MON EVENING. AS SUCH...EXPECT
MODERATE TO LOCALLY HEAVY SNOW TO CONTINUE IN MQT/BARAGA COUNTIES AS
WELL AS GOGEBIC COUNTY THROUGH THE NIGHT SUNDAY INTO MONDAY. THE
BEST LIFT RAPIDLY BECOMING ENTRENCHED IN THE DGZ SUNDAY EVENING AS
THE UPPER TEMPS DROP...EXPECT THE SNOW TO BECOME MUCH MORE FLUFFY
BUT ALSO ACCUMULATE MUCH FASTER WITH RATIOS CLOSE TO 25:1 BY MON
MORNING. SOME AREAS IN THE WATCH AREA COULD SEE ANOTHER 8-12 INCHES
OF SNOW SUN NIGHT INTO MONDAY.
INTERESTINGLY...THERE ARE SEVERAL VERY GOOD CIPS ANALOG EVENTS FOR
THIS SYSTEM. THEY ALL GENERALLY SHOW THE WATCH AREA SEEING
SIGNIFICANT 72 HOUR SNOWFALL. NOT SURE IF WE WILL SEE ANY LONGER
PERIOD OF HEAVY SNOWFALL...RATHER I AM THINKING THAT IT WILL BE
GENERALLY A PERSISTENT SNOWFALL FOR 24-36 HOURS WHICH WILL ALLOW
WARNING CRITERIA TO BE REACHED. EVEN MORE INTERESTING...DESPITE THE
FACT THAT GOGEBIC COUNTY WILL BE FURTHEST REMOVED FROM THE
SYSTEM...THE CURRENT NWP AND ALSO THE CIPS GUIDANCE SUGGEST THAT
THIS AREA COULD SEE THE MOST SNOWFALL OUT OF THIS EVENT. WE WILL
SEE...
ANY REMAINING LES SHOULD END RAPIDLY MON NIGHT/TUE MORNING AS THE
HIGH PRES RIDGE BUILDS ACROSS THE FORECAST AREA. STILL LOOKS QUITE
COLD TUE MORNING ACROSS THE WEST WITH LIGHT WINDS/CLEAR SKIES. TEMPS
10-20 BELOW NOT OUT OF THE QUESTION IN THE NORMALLY COLDER SPOTS.
THE ECMWF AND GEM ARE IN GOOD AGREEMENT IN LIGHT OVERRUNNING/WARM
ADVECTION SNOW CHRISTMAS EVE NIGHT INTO CHRISTMAS DAY ACROSS THE
ENTIRE FORECAST AREA. SOME HINTS THAT THERE MIGHT BE SOME LAKE
ENHANCEMENT OFF OF LAKE MICHIGAN TUESDAY NIGHT AND HAVE OPTED TO
CONTINUE LIKELY POPS ACROSS THE EASTERN PART OF THE FORECAST AREA
TUE NIGHT INTO CHRISTMAS DAY. SOME DIFFERENCES EMERGE THU INTO
FRIDAY REGARDING THE EVOLUTION AND THE TROUGH WITH THE ECMWF BEING
DEEPER AND FURTHER SOUTH COMPARED TO THE GFS. REGARDLESS...SENSIBLE
WEATHER SHOULD GENERALLY THE SAME WITH EITHER MODEL WITH LES IN THE
NW FAVORED SNOWBELTS CHRISTMAS NIGHT INTO THU NIGHT BEFORE
DIMINISHING ON FRIDAY AS HIGH PRES BUILDS OVERHEAD. TEMPS STILL LOOK
BELOW NORMAL THROUGH THE EXTENDED WITH 850MB TEMPS -20 TO -25C WED
NIGHT/THU WARMING TO -15 TO -20C BY FRIDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1229 AM EST SAT DEC 21 2013
WITH ABUNDANT LOW LEVEL MOISTURE AND LIGHT WINDS LINGERING OVER THE
REGION...MAINLY MVFR CIGS ARE EXPECTED THROUGH THE FCST PERIOD AT
CMX AND IWD. THERE MAY BE A PERIOD OF SNOW SHOWERS AT CMX THAT COULD
REDUCE VSBY INTO THE IFR RANGE IF A CONVERGENCE ZONE OVER THE
WESTERN LAKE SAGS INTO THE AREA. HOWEVER...CONFIDENCE IN THE TIMING
AND PLACEMENT OF THIS FEATURE IS LOW. WEAK DOWNSLOPE WESTERLY FLOW
AT SAW WILL FAVOR VFR CONDITIONS UNTIL LATE SAT AFTERNOON WHEN WINDS
VEER TO THE NNE AND UPSLOPE FLOW LEADS TO MVFR CIGS AND SOME LIGHT
SNOW SHOWERS.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 457 AM EST SAT DEC 21 2013
LIGHT WINDS TODAY WITH TROUGH OVER THE LAKE THEN AS THE TROUGH SINKS
SOUTH TONIGHT...EXPECT STRONG AND GUSTY NORTHEAST WINDS TO 30 KTS
OVER MUCH OF LAKE SUPERIOR INTO SUNDAY...FURTHER STRENGTHENED BY LOW
PRESSURE LIFTING ACROSS LOWER MICHIGAN. COULD BE GALE GUSTS OVER
THE WEST WITH CHANNELING BETWEEN MINNESOTA SHORELINE AND KEWEENAW
PENINSULA. DURING THIS PERIOD OF STRONGER WINDS THERE WILL BE
FREEZING SPRAY. EXPECT THE LOW TO LINGER A SURFACE TROUGH OVER THE
UPPER GREAT LAKES THROUGH MONDAY AND KEEP WINDS UP TO 25 KTS. HIGH
PRESSURE WILL CROSS THE UPPER GREAT LAKES ON MONDAY NIGHT...WHILE A
LOW PRESSURE SYSTEM BEGINS TO TAKE SHAPE IN THE CANADIAN PRAIRIES.
THIS LOW WILL LEAD TO INCREASING SOUTHERLY WINDS ACROSS LAKE
SUPERIOR ON TUESDAY. WHEN THE LOW MOVES THROUGH THE REGION ON
WEDNESDAY...WINDS WILL BECOME WESTERLY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER STORM WATCH FROM SUNDAY MORNING THROUGH MONDAY EVENING
FOR MIZ002-004-005-009.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLA
LONG TERM...MRD
AVIATION...JLB
MARINE...JLA
AREA FORECAST DISCUSSION...UPDATED
NWS TWIN CITIES/CHANHASSEN MN
952 PM CST SUN DEC 22 2013
.UPDATE...
ISSUED AT 945 PM CST SUN DEC 22 2013
HAVING A HARD TIME KEEPING UP WITH THE BITTER COLD TEMPERATURES
ACROSS WESTERN MINNESOTA THIS EVENING. THE -10F ISOTHERM IS
BEGINNING TO INCH INTO WESTERN MN...WITH WIND CHILLS IN THE -30S.
THE RAP AND HOPWRF MODELS ARE SHOWING WIDESPREAD -20S FOR AIR
TEMPERATURES IN THOSE AREAS LATE TONIGHT...WITH WIND REMAINING IN
THE 10-15 MPH RANGE. SINCE IT IS SO CLOSE TO WARNING CRITERIA
ALREADY BEFORE 10 PM...UPGRADED MOST OF WESTERN MN AND THE MN
RIVER VALLEY TO A WIND CHILL WARNING. IN ADDITION...HIGHS TOMORROW
WILL STRUGGLE TO GET MUCH ABOVE 10 BELOW IN THESE AREAS AND WIND
CHILLS WILL CONTINUE TO BE IN THE -30S FOR MOST OF THE DAY.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 221 PM CST SUN DEC 22 2013
LIGHT SNOW WILL PERSIST ACROSS THE EASTERN CWA FOR MUCH OF THE
PERIOD...WITH COLD AIR ADVECTION SPREADING ACROSS THE SOUTHWESTERN
PART OF THE CWA. EARLY AFTERNOON WATER VAPOR IMAGERY TOGETHER WITH
500MB HEIGHTS AND WINDS SHOWS A HIGH AMPLITUDE TROUGH ACROSS CENTRAL
NORTH AMERICA...WITH A NORTH/SOUTH ORIENTED JET OVER THE EASTERN
SPINE OF THE ROCKIES. AN AREA OF POSITIVE VORTICITY OWING TO THE
SPEED SHEAR ON THE POLEWARD SIDE OF THIS JET WILL CONTINUE TO ROTATE
ACROSS THE UPPER MIDWEST.
500M HEIGHT FALLS WILL CONTINUE AHEAD OF THIS WAVE ACROSS NORTHERN
MN/WI...RESULTING IN AN INVERTED TROUGH AND PERIODS OF LIGHT SNOW.
NORTHWEST WINDS WILL INCREASE TO AROUND 20MPH AND CONTINUE
OVERNIGHT. THEREFORE HAVE KEPT LOW TEMPERATURES SLIGHTLY ABOVE
GUIDANCE...FAVORING THE SCENARIO OF STRONGER WINDS AND SLIGHTLY
WARMER TEMPERATURES...AS OPPOSED TO WEAKER WINDS AND LOWER TEMPS.
EITHER RESULT STILL PRODUCES WIND CHILL VALUES LESS THAN 25 BELOW
ZERO ACROSS MOST OF THE WESTERN CWA...WHICH WILL REBOUND SLIGHTLY
MONDAY AFTERNOON...BUT FALL OFF AGAIN MONDAY NIGHT. FOR SIMPLICITY/S
SAKE...HAVE GONE WITH ONE LONG WIND CHILL ADVISORY THROUGH TUESDAY
MORNING. THIS WILL LIKELY NEED TO BE EXPANDED FARTHER EAST...AND
PERHAPS UPGRADED TO A WARNING ACROSS THE NORTHWEST MONDAY NIGHT.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 221 PM CST SUN DEC 22 2013
GENERALLY COLD NORTHWEST UPPER FLOW WILL PREDOMINATE THROUGH THE
LONG TERM... WITH PERIODIC CLIPPERS AND REINFORCING SHOTS OF COLD
AIR. THE MAIN FEATURE OF INTEREST WILL BE A SHORTWAVE CURRENTLY
SOUTH OF ALASKA WHICH WILL MOVE THROUGH THE REGION TUESDAY
AFTERNOON AND EVENING... BRINGING A DECENT SHOT OF LIGHT SNOW TO
THE AREA. THE GFS... NAM... AND ECMWF ARE GENERALLY IN GOOD
AGREEMENT ON THE SYSTEM... WITH SOME DIFFERENCES IN TIMING AND
LOCATION OF THE HEAVIEST PCPN. THE THALER-QC DIAGNOSTICS FROM THE
RESPECTIVE MODELS SHOW PCPN TOTALS QUITE SIMILAR TO WHAT IS COMING
DIRECTLY FROM THE MODELS... AND LOCAL LATENT HEAT DEPRIVATION
SENSITIVITY RUNS SHOW MINIMAL DIFFERENCE IN SOLUTIONS. ALL OF THIS
POINTS TOWARD HIGH CONFIDENCE OF A 6 HOUR OR SO WINDOW OF LIGHT TO
MODERATE SNOWFALL. WITH LIQUID PCPN RUNNING FROM A TENTH TO AROUND
A QUARTER OF AN INCH... WOULD EXPECT TO SEE TOTALS GENERALLY IN A
RANGE FROM 1 TO 3 INCHES. MIXING RATIOS OF 2-2.5 G/KG ARE PRESENT
ON THE 290K SURFACE... WHICH WOULD EQUATE TO AROUND 5 INCHES IN 12
HOURS WITH THE IMR METHOD... SO 2.5 INCHES IS PROBABLY ABOUT RIGHT
FOR MOST SPOTS. OF COURSE... MUCH WILL DEPEND ON RATIOS... SO IF
WE SEE RATIOS GET UP NEAR 25 TO 1... THEN WE COULD SEE SOME
LOCALIZED TOTALS TO 4 OR EVEN 5 INCHES. THE FORECAST SOUNDINGS DO
SUGGEST A DECENT DEPTH OF -12 TO -18 C TEMPERATURES IN THE
SATURATED PORTION OF THE PROFILE... SO THE RATIO ISSUE WILL
CERTAINLY NEED TO BE MONITORED. EVEN WITH ONLY A LIGHT SNOW
EXPECTED... IT COULD BE IMPACTFUL GIVEN THAT IT WILL OCCUR DURING
THE LATE AFTERNOON AND EVENING HOURS ON CHRISTMAS EVE... SO IT IS
SOMETHING TRAVELERS WILL NEED TO CONSIDER WHEN MAKING PLANS. ON
CHRISTMAS DAY WE SHOULD EVENTUALLY SEE WEST WINDS PICK UP AND
SHIFT TO THE NORTHWEST LATER IN THE DAY. THE STRONGEST WINDS
SHOULD IMPACT WEST CENTRAL AND SOUTHERN PORTIONS OF THE AREA...
WHICH COULD LEAD TO BLOWING/DRIFTING SNOW ISSUES... WHICH WILL BE
AN ADDITIONAL CONCERN FOR TRAVELERS ON CHRISTMAS DAY.
THE OTHER ISSUE OF CONCERN WILL BE VERY COLD TEMPERATURES AND WIND
CHILLS MONDAY NIGHT INTO TUESDAY MORNING... WITH THE SURFACE RIDGE
SETTLING OVER THE AREA AND A COATING OF FRESH SNOW THANKS TO WHAT
WE/RE SEEING TODAY INTO MONDAY. THE ENTIRE AREA WILL GET WELL
BELOW ZERO... WITH READINGS OF 20 TO 25 BELOW LIKELY OVER PORTIONS
OF THE WEST/NORTHWEST FORECAST AREA. EVEN THE TWIN CITIES METRO
SHOULD SEE READINGS TO NEAR 15 BELOW. THE ONLY AREA WHICH WILL
ESCAPE THE WORST OF THE COLD WILL BE EAST OF I-35 WHERE CLOUDS
LOOK TO HANG ON FOR AT LEAST HALF OF MONDAY NIGHT BEFORE RIDGING
IS SUFFICIENT TO SCOUR THEM OUT. ALTHOUGH WINDS WILL BE LIGHT...
EVEN THE SLIGHT ZEPHYR EXPECTED WILL RESULT IN WIND CHILLS A GOOD
10 TO 15 DEGREES LOWER THAN TEMPERATURES... MEANING SOME LOCATIONS
IN THE NORTHWEST PORTION OF THE AREA COULD SEE WIND CHILLS NEAR 40
BELOW BY 6 AM TUESDAY. DECIDED TO EXTEND THE EXISTING WIND CHILL
ADVISORY THROUGH TUESDAY MORNING FOR NOW... SINCE ADVISORY
CRITERIA ARE PRETTY MUCH ASSURED. LATER SHIFTS CAN LOOK INTO
PERHAPS GOING WITH WIND CHILL WARNINGS FOR A PORTION OF THE AREA
FOR LATE MONDAY NIGHT INTO TUESDAY MORNING.
WE WILL LIKELY KEEP SOME SNOW SHOWERS/FLURRIES AROUND ON CHRISTMAS
DAY AS CYCLONIC FLOW LINGERS... BUT THE MAIN ISSUE IF ANY WILL BE
BLOWING/DRIFTING SNOW AS MENTIONED ABOVE. RIDGING LOOKS TO WORK IN
WEDNESDAY NIGHT THROUGH THURSDAY... WITH COLD AND DRY CONDITIONS
ACROSS THE AREA. NORTHERN PORTIONS OF THE AREA COULD SEE SOME
LIGHT SNOW CHANCES AGAIN OVER THE UPCOMING WEEKEND AS WE SEE A FEW
BRIEF WARM-UPS AND SUBSEQUENT COOL-DOWNS AS CLIPPERS DROP
SOUTHEAST/EAST IN THE NORTHWEST UPPER FLOW ALONG THE CANADIAN
BORDER.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 545 PM CST SUN DEC 22 2013
MVFR CONDITIONS EXPECTED TO PERSIST FOR MUCH OF THE OVERNIGHT AND
INTO MONDAY ACROSS CENTRAL/EASTERN MN AND WESTERN WI. MAINLY VFR
AT AXN AND RWF AS THESE SITES REMAIN ON THE WESTERN PERIPHERY OF
THE SYSTEM GENERATING SNOW TO THE EAST. DRIER AIR WILL FINALLY
PUSH INTO THE REST OF THE TAF SITES LATE MONDAY. NORTHWEST WINDS
AROUND 10 KTS WILL PERSIST THROUGH THE PERIOD.
KMSP...MVFR CONDITIONS THROUGH MONDAY IN LIGHT SNOW...WITH VFR
CONDITIONS THEREAFTER. SNOW ACCUMULATIONS WILL REMAIN AROUND AN
INCH OR LESS.
/OUTLOOK FOR KMSP/
TUE...VFR WITH MVFR/IFR AND -SN BY AFTN. WINDS S AT 10G20KTS.
WED...MVFR WITH -SN/BLSN POSSIBLE. WINDS W AT 15G25KTS.
THU...VFR. WINDS W AT 10KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WIND CHILL ADVISORY UNTIL NOON CST TUESDAY FOR MNZ042-043-
049>051-058-059-066>069-076-077-084-085-091>093.
WIND CHILL WARNING UNTIL NOON CST TUESDAY FOR MNZ041-047-048-
054>057-064-065-073>075-082-083.
WI...NONE.
&&
$$
UPDATE...BORGHOFF
SHORT TERM...TRH
LONG TERM...JRB
AVIATION...BORGHOFF
AREA FORECAST DISCUSSION
NWS DULUTH MN
341 PM CST SAT DEC 21 2013
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 330 PM CST SAT DEC 21 2013
AT 330 PM...IT WAS FAIRLY QUIET ACROSS THE NORTHLAND. THERE
CONTINUED TO BE FLURRIES AND ISOLATED SNOW SHOWERS FOR MOST AREAS.
THE EXCEPTION WAS ALONG THE NORTH SHORE OF LAKE SUPERIOR...WHERE
AN INCH OF SNOW FELL THIS AFTERNOON IN COASTAL LAKE AND COOK
COUNTIES. TEMPERATURES RANGED FROM THE SINGLE DIGITS AT
INTERNATIONAL FALLS TO THE 20S IN NORTHWESTERN WISCONSIN.
THE HIGH RESOLUTION MODEL DATA INDICATES THAT THERE WILL BE
PERIODS OF LAKE EFFECT SNOW CONTINUING ACROSS WESTERN LAKE
SUPERIOR TONIGHT. THE HRRR AND WRF INDICATE A CONVERGENT BAND OF
SNOW ACROSS THE WESTERN PORTION OF THE LAKE...WITH SEVERAL WAVES
IN THE LINE. THIS WILL RESULT IN LOCAL SWIRLS AND CONSIDERABLE
VARIABILITY TO THE LAKE EFFECT OVERNIGHT. STRONG NORTHEAST WINDS
AT ROCK OF AGES CONTINUED ON ONE SIDE OF THIS BAND...WITH GUSTY
SOUTHERLY WINDS AT DEVILS ISLAND ON THE OTHER SIDE.
WINDS WILL OVERWHELMINGLY BECOME NORTHEAST TO NORTH OVERNIGHT AND
ON SUNDAY...WHILE THE OTHER SYSTEM MOVES IN FROM THE WEST. THE
RESULT WILL BE A PHASING OF THE MOISTURE ACROSS THE WESTERN GREAT
LAKES. OVERALL LOOKING FOR AN INCH OR TWO FOR MUCH OF THE AREA
TONIGHT...AND ANOTHER INCH OR TWO ON SUNDAY.
THE EXCEPTION WILL BE ACROSS THE SOUTH SHORE OF LAKE SUPERIOR. WE
COULD HAVE HANDLED THIS EVENT IN A COUPLE WAYS REGARDING HEADLINES
BUT AFTER EXTENSIVE DISCUSSION...WE DECIDED TO ISSUE A LAKE EFFECT
SNOW ADVISORY FOR THE PERIOD TONIGHT THROUGH MONDAY...RATHER THAN
HAVING A LARGE LAKE EFFECT SNOW WARNING OUT FOR 5 PERIODS...WITH
GENERALLY ADVISORY TYPE SNOW FOR MOST OF THE PERIODS. THINK THERE
IS A FAIR CHANCE WE MAY NEED TO UPGRADE TO A WARNING FOR MONDAY.
BUT FOR TONIGHT AND SUNDAY...WE ARE LOOKING AT TRANSITIONAL LAKE
EFFECT SNOWFALL BANDS...SWIRLS AND CONVERGENCE BANDS...AND THE
RESULT SHOULD BE WIDESPREAD ADVISORY TYPE SNOW.
WE ALSO COULD HAVE ISSUED THE ADVISORY FOR TONIGHT THROUGH SUNDAY
NIGHT...AND MAINTAINED THE WATCH FOR MONDAY...BUT FOR SIMPLICITY
SAKE...DECIDED TO HOLD OFF ON THAT FOR NOW. THE MAIN FOCUS FOR A
POTENTIAL WARNING ON MONDAY WOULD BE THE GOGEBIC RANGE. WE DO
AGREE THAT ADDED UP OVER 4-5 PERIODS...THE AMOUNTS COULD BE
IMPRESSIVE...SOME ON THE ORDER OF A FOOT OR MORE IN THE GOGEBIC
RANGE.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 345 PM CST SAT DEC 21 2013
FIRST CONCERN IN EXTENDED IS ON LONG DURATION LAKE EFFECT SNOW THAT
WILL PERSIST THROUGH MONDAY EVENING. THE 12Z RUNS OF THE
GFS/ECM/NAM ARE IN AGREEMENT THAT THE H85-H50 TROUGH AXIS PASSES
OVER WRN LAKE SUPERIOR DURING THE DAY MONDAY...BRINGING A STRONG
PUSH OF CAA WITH H85 TEMPS FALLING INTO THE NEGATIVE 20S AND
BOUNDARY LAYER WINDS BACKING OUT OF THE NORTH THEN NORTHWEST.
ALTHOUGH CONDITIONS REMAIN FAVORABLE FOR A FEW INCHES OF LIGHT SNOW
ALONG THE SOUTH SHORE OF LAKE SUPERIOR SUN NIGHT...LAPSE
RATES/INVERSION HTS SIGNIFICANTLY INCREASE MONDAY DUE TO THE ARRIVAL
OF THE COLD AIR. HAVE INCREASED QPF/SN AMOUNTS MONDAY TO ACCOUNT
FOR THE HIGHER INSTABILITY.
FOCUS TURNS TO ELONGATED VORT MAX THAT DROPS OUT OF CANADA AND
ACROSS THE NRN PLAINS TUESDAY/WEDNESDAY. LATEST ECM/GFS BOTH
SUGGEST THE DIGGING WAVE...WITH SFC REFLECTION COLD FRONT...SWEEPS
ACROSS THE NORTHLAND DURING THE CHRISTMAS HOLIDAY. CURRENT TIMING
WOULD FAVOR A FEW INCHES OF SNOW OVER MUCH OF THE REGION TUESDAY
NIGHT. HOWEVER...IF TIMING SLOWS...ITS POSSIBLE THE COLD FRONT/LIGHT
SNOW HOLD OFF UNTIL CHRISTMAS DAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1230 PM CST SAT DEC 21 2013
MAINLY MVFR CEILINGS AND LIGHT FLURRIES WILL BE FOUND TODAY WITH
POCKETS OF CLEARING. MVFR CEILINGS WILL AGAIN INCREASE IN COVERAGE
OVERNIGHT AS LIGHT SNOW DEVELOPS ACROSS THE AREA SUNDAY MORNING.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 8 13 -8 1 / 70 90 70 20
INL -9 2 -20 -5 / 40 50 20 10
BRD 4 11 -13 -2 / 70 90 50 10
HYR 11 21 1 6 / 60 90 80 70
ASX 15 21 9 9 / 70 90 90 80
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...LAKE EFFECT SNOW ADVISORY FROM MIDNIGHT TONIGHT TO 6 PM CST
MONDAY FOR WIZ001>004.
LS...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 4 AM CST MONDAY
FOR LSZ121-140>148.
&&
$$
SHORT TERM...DAP
LONG TERM...GRANING
AVIATION...GRANING
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1154 AM CST Sat Dec 21 2013
.UPDATE...
Issued at 1152 AM CST SAT DEC 21 2013
No significant changes have been made to the forecast thinking. The
past few hours have seen a relative lull in precipitation, however
freezing rain and sleet appears to be rapidly filling back in across
eastern KS and western MO in an area of increasing isentropic ascent.
Precipitation will likely continue to expand through mid afternoon
across areas near and south of the Highway 36 corridor. Thermal
profiles suggest most of this precip will take the form of sleet or a
sleet/freezing rain mix along and north of a Kansas City to Macon
line, with mostly freezing rain to the south. Could see additional
ice accumulations around a tenth of an inch for the
Butler/Sedalia/Boonville areas through sunset with local amounts up
to two tenths of an inch. Further north across the KC to Moberly
corridor there will likely be a thin glazing of ice with minor (1/4"
or less) accumulations of sleet. Higher threat for icing will be
south of the Missouri River with more sleet to the north.
Later tonight all models continue to point to several inches of
accumulating snow occurring from the KC and STJ areas northeast toward
Kirksville. The NAM in particular is supportive of a frontogenetical
band of heavy snow developing somewhere between Kansas City and St.
Joseph that could provide enhanced snowfall rates up to 2" per hour
and possibly thunder. However other models including the RAP are less
suggestive of this and differ substantially with where such a band
would set up. For now no major changes are being made to snow totals
tonight, with a band of 5"+ snows setting up near and just north of
the KC/Kirksville corridor. If frontogenetical forcing does begin to
dominate later this evening, then there could be some enhanced snow
amounts around 8" somewhere near St. Joseph or Kansas City with a
sharper gradient between areas that receive heavy snow and areas that
see little snowfall.
&&
.SHORT TERM...(Today through Sunday Night)
Issued at 353 AM CST SAT DEC 21 2013
Early morning water vapor imagery shows an impressive plume of Pacific
moisture spreading across the central CONUS ahead of a deep upper
trough centered over the northern Chihuahua state of Mexico. Precipitation
has broken out in earnest since mid afternoon from Oklahoma into the
Ozarks, and the anticipated northward shift of this moisture and the
arrival of the upper low tonight remain the primary forecast concerns
through the next 24 hours.
TODAY
------
IMPACTS: Minor ice accumulations generally along and south of
a Kansas City to Moberly line -- highest mid Missouri southward.
Regional radar imagery mimics the inherited forecast rather well. As
expected, precipitation has had difficulties gaining latitude north
of I-44, owing to persistent warm advection from eastern OK into nrn
AR along the nose of a 60+ knot low level jet, yielding a broken arc
of thunderstorms and substantial trailing stratiform region from
central OK into srn MO. Meanwhile, isentropic downglide continues to
erode at northward precipitation advances, with a considerable dry
layer still present between the low stratus and the Pacific moist
plume aloft. A few pockets of freezing rain have reached the far srn
CWA (Clinton-Sedalia-Boonville) early this morning, but impacts have
been minimal. We`ve also received some sleet reports which were
puzzling given the +6 to +8C warm nose aloft at 800mb, but a more in-depth
look at soundings shows that 925mb temps bottom at -8 to -10C, enough
to refreeze some of those rain drops. That cold layer is expected to
moderate some this morning, keeping most of the precip as FZRA.
Although low level flow trajectories are currently from the SW,
keeping most of the precip over OK/AR/srn MO, I anticipate that the
flow will back this morning as the upper trough begins to lift across
the TX/MX border and become negative tilt. This , coupled with
increasing large scale ascent, should allow a net northward
transport of the steadier precipitation into the forecast area
before daybreak and continuing throughout the day. Heavier
precipitation should remain focused just southeast of the CWA border
from Springfield-Columbia-St. Louis and points south. Travel down
toward the I-44 corridor is *highly* discouraged. Locally, freezing
rain (possibly mixed sleet north and west) will result in minor ice
accretion of a few hundredths to around a tenth of an inch, with the
exception of Clinton-Sedalia-Boonville where up to a third of an inch
of icing is possible. Maintenance of northerly low level ageostrophic
flow should keep temperatures below freezing throughout the day.
TONIGHT:
--------
IMPACTS: Light icing will diminish eastern areas this evening. Rapid
snow accumulations become the main concern across portions of northwest
and north central Missouri from sundown through 6 AM.
Once again, the forecast is anything but a slam dunk with a rather
sharp snow gradient anticipated across the CWA. Conveying this
message to partners and customers may be more challenging than the
forecast itself, as there will likely be close proximity between the
haves and have nots when all is said and done.
As the upper low matures on its approach early this evening, column
saturation will occur quickly over NW MO with temperature profiles
rapidly cooling below freezing. Models remain consistent with taking
the core of the mid level center across Kansas City to Kirksville
between 06 and 09Z, with deformation of the mid level frontal zone
yielding rather prolific snowfall rates in a 100 mile zone northwest
of the center track. Despite the fast system speed and an increasingly
disconnected warm conveyor source region, cross-sections show
vigorous ascent (30+ ubar/s) associated with strong mid-level
frontogenesis within the optimal -12 to -18C dendritic growth region.
This should yield a quick 4 to 7" snowfall in meso-alpha scale band.
While the placement of highest snow accumulations and amounts have not
changed, the forecast gets rather dicey east of a Kansas City to
Kirksville line. Although not well handled in most of the model
output, it would seem to reason that narrow dry slot would develop
given a system of this strength/maturity, and punch east of the mid
level low center during the evening as the cyclone reaches maturity.
If this occurs, snowfall accumulations over the eastern CWA may be
significantly reduced if not eliminated as ice nuclei are scoured.
Even a slight shift in the cyclone track could mean the difference
between a location receiving plowable snows and potentially a non-
event. This gradient may perhaps exist across the KC metro itself, so
we will need to remain focused on this message until the deformation
zone becomes clear by late afternoon to our SW.
The upper low should continue to accelerate NE after midnight, and
most of the accumulating snowfall will shift north of the Iowa border
by 12Z. The next shift may want to consider trimming the winter storm
warning end time back to around 12Z.
SUNDAY/SUNDAY NIGHT:
--------------------
IMPACTS: Bitter cold.
Cloudy and somewhat blustery conditions expected. Temperatures will
barely reach the mid 20s, with wind chills in the teens.
With the passage of the longwave mid level trough axis Sunday
evening, low level flow will turn anti-cyclonic. The leading edge of
stronger gradient flow, associated with a surge of low level arctic
air, will push into the CWA by early evening as skies gradually
clear. Some areas could see the coldest lows of the season given the
magnitude of this airmass coupled with fresh snow cover.
Bookbinder
.LONG TERM...(Monday through Friday)
Issued at 353 AM CST SAT DEC 21 2013
Beginning of the work week continues to look cold as the large scale
trough that helped bring the weekends winter weather will still be
in place across the Plains States. This will allow a surge of cold
air to spread across the central Plains Sunday night through Monday
night. Advertisements from the models indicate the 850mb
temperatures in the -10C to -15C range will move south with a
1037mb surface high. This will keep temperatures in the teens --if
not colder-- for Monday`s high with early morning lows Tuesday
ranging below zero in all areas north of the Missouri River. Given
the current forecast, any light wind Tuesday morning will result in
dangerously cold wind chill values. However, later Tuesday the
center of the cold surface high will slide to our east, moderating
our temperatures as we move forward through the week. This should
allow temperatures to creep back into the 20s and 30s for Christmas
day. A few of the medium range models indicate that another
shortwave trough swinging through the northern Plains into the Great
Lakes may induce a bit of light precipitation on the back side of
the exiting surface high Wednesday, but confidence is rather low on
this potential.
&&
.AVIATION...(For the 18Z TAFS through 18Z Sunday Afternoon)
Issued at 1152 AM CST SAT DEC 21 2013
Sleet with some freezing rain mixed in has developed near MCI with
additional activity filling in upstream toward ICT. There will likely
be some breaks in this activity before it becomes more widespread
toward 21Z, but impacts are significant enough to just carry
prevailing FZRAIP through the afternoon. Increasing activity toward
21Z could lead to a thin glazing of ice and/or minor sleet
accumulations for MKC/MCI while STJ/IRK are more likely to see sleet
and some snow.
Mixed precipitation will change to all snow toward 00Z for STJ/MCI
and closer to 03Z for IRK/DMO areas. MCI-IRK corridor has the
potential to see heavy snow with visibilities approaching or
exceeding airport minimums and snowfall rates exceeding 1" per hour.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...WINTER STORM WARNING until Noon CST Sunday FOR KSZ057-060-105.
WINTER STORM WARNING until Noon CST Sunday FOR KSZ025-102>104.
MO...WINTER STORM WARNING until Noon CST Sunday FOR MOZ032-033-
037>040-043>046-053-054.
WINTER STORM WARNING until Noon CST Sunday FOR MOZ001>008-
011>017-020>025-028>031.
&&
$$
UPDATE...Hawblitzel
SHORT TERM...Bookbinder
LONG TERM...Cutter
AVIATION...Hawblitzel
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1022 AM EST SAT DEC 21 2013
.SYNOPSIS...WARM SOUTHERLY FLOW AROUND BERMUDA HIGH PRESSURE WILL
CONTINUE THIS WEEKEND...AHEAD OF A MOISTURE-LADEN COLD FRONT THAT
WILL CROSS OUR REGION SUNDAY NIGHT AND MONDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1020 AM SATURDAY...
TODAY: A WARM/MILD DAY IS EXPECTED TODAY ACROSS CENTRAL NC... WITH
HIGH PRESSURE AT THE SURFACE AND ALOFT REMAINING ANCHORED OFF THE
SOUTHEAST U.S. COAST. THIS WILL RESULT IN A CONTINUED
WARM/MOISTENING DEEP SOUTH TO SOUTHWESTERLY RETURN FLOW ACROSS OUR
AREA. LOW LEVEL FLOW IS EXPECTED TO STRENGTHEN TODAY AS A POTENT S/W
LIFTS NORTHEASTWARD INTO THE SOUTHERN PLAINS OUT OF WEST TEXAS. THE
MAIN LOW LEVEL JET IS EXPECTED TO REMAIN TO THE WEST OF THE AREA
TODAY... WITH THE THE SURFACE FRONT EXPECTED TO SLOWLY SHIFT
EASTWARD ACROSS THE OHIO RIVER VALLEY AND ARK-LA-TEX REGIONS TODAY.
THUS... THINK THE BULK OF ANY LIGHT SHOWER ACTIVITY WILL GENERALLY
REMAIN JUST TO THE WEST OF OUR AREA TODAY. THE BIG QUESTIONS THAT
REMAIN... IS HOW MUCH CLOUD COVER WE WILL HAVE TODAY AND THE IMPACTS
ON HIGH TEMPS. THE LATEST GFS AND RAP ARE MORE AGGRESSIVE THAN THE
NAM WRT TO LOW LEVEL CLOUD COVER TODAY... ESPECIALLY ACROSS OUR
WESTERN REACHES. IN ADDITION... ALL MODEL GUIDANCE CONDITIONS TO
SHOW MID AND HIGH LEVEL CLOUD COVER STREAMING ACROSS THE REGION
TODAY... AT TIMES THICKER... AS WEAK EMBEDDED IMPULSES MOVE THROUGH
THE SOUTHWESTERLY FLOW ALOFT. FOR NOW WILL TREND THE FORECAST A
LITTLE BIT MORE TOWARDS THE GFS/RAP (WHICH IS A GOOD BLEND BETWEEN
THE GUIDANCE) GIVEN THE EXPECTED STRENGTHENING OF THE LOW LEVEL FLOW
AND QUITE A BIT OF LOW LEVEL CLOUD COVER TO THE SOUTH-SOUTHWEST OF
THE REGION CURRENTLY (ACROSS THE UPSTATE OF SC). GIVEN THIS... WILL
TRIM HIGHS BACK BY A DEGREE OR TWO ACROSS THE WESTERN HALF OF THE
AREA. STILL THESE HIGHS WILL BE NEAR OR ABOVE RECORD VALUES FOR TODAY.
EXPECT HIGHS TEMPS WILL RANGE FROM THE UPPER 60S NEAR 70 NW TO THE UPPER
70S SE. -77
TONIGHT: SKIES WILL LIKELY LARGELY CLEAR FOR A TIME THIS EVENING AND
EARLY TONIGHT...AS THE FLOW ALOFT BACKS IN RESPONSE TO THE APPROACH
OF THE DEAMPLIFYING UPPER LOW FROM WEST TX...AND FURTHER RIDGE
AMPLIFICATION OVER THE CARIBBEAN...AND CONSEQUENTLY BOWS THE MID-
HIGH CLOUDINESS NORTHWESTWARD TOWARD THE APPALACHIANS. THIS WILL SET
THE STAGE FOR A HIGHER-THAN-PREVIOUS-DAYS PROBABILITY AND COVERAGE
OF STRATUS OVERNIGHT...AMIDST A STEADILY STRENGTHENING WAA REGIME.
THIS PATTERN ALSO SUPPORTS THE INHERITED CHANCE OF SHOWERS OVER THE
WESTERN PIEDMONT...WHOSE DEPTH WILL BE LIMITED BY A CAPPING
INVERSION ALOFT PER BUFR FORECAST SOUNDINGS...AND A LACK OF MORE
APPRECIABLE LOW LEVEL MOISTURE AND RELATED INSTABILITY. MILD WITH
LOWS IN THE LOWER TO MIDDLE 60S - ALSO AROUND RECORD HIGH MINS FOR
THE DATE. -26
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 305 AM SATURDAY...
DEEP SOUTHWESTERLY FLOW AHEAD OF AN APPROACHING COLD FRONT WILL TAP
INTO GULF MOISTURE... BRINGING PWS OF OVER 1.5 INCHES TO THE AREA
SUNDAY... NEAR MAX VALUES RECORDED FOR DECEMBER. HEAVY RAINFALL WILL
BE A POTENTIAL CONCERN... MAINLY OVER URBAN AREAS AS QPF REMAINS
SHORT OF FLASH FLOOD GUIDANCE AT THIS TIME. MID LEVEL LAPSE RATES
REMAIN WEAK... AND INSTABILITY LOW... SO THE SEVERE THREAT REMAINS
NEGLIGIBLE. ANY STORMS THAT DO DEVELOP MAY TAP IN TO THE STRONG 60-
65 KT LLJ AND BRING THE POTENTIAL FOR STRONG GUSTY WINDS ALONG WITH
HEAVY RAINFALL. SHEAR PROFILES WOULD BE SUPPORTIVE OF ROTATION...
HOWEVER THIS GOES STRONGLY AGAINST CLIMATOLOGY AND WITH THE
AFOREMENTIONED ENVIRONMENT... THIS IS A VERY LOW END THREAT. NEAR
RECORD HIGHS IN THE 70S.
THE COLD FRONT CROSSES THE AREA MONDAY AFTERNOON... MAKING IT TO THE
CAROLINA COAST BY 03Z TUES. HIGHS IN THE 60S. SHOWERS WILL END FROM
WEST TO EAST DURING THE EVENING HOURS. LOWS IN THE 30S WITH STRONG
COLD ADVECTION.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 307 AM SATURDAY...
UPPER LEVEL TROUGH MOVES OFF THE EAST COAST ON TUESDAY... AND THE
COLUMN DRIES SIGNIFICANTLY AS UPPER LEVEL FLOW BECOMES WESTERLY.
HIGH PRESSURE OVER THE MISSISSIPPI VALLEY ON TUESDAY WILL BUILD OVER
THE EAST COAST WEDNESDAY. HIGHS IN THE 40S ON TUESDAY AND WEDNESDAY
WILL MODERATE TOWARD NORMAL... IN THE 50S... THURSDAY THROUGH FRIDAY.
AN UPPER LEVEL TROUGH OVER CENTRAL US ON THURSDAY WILL MOVE EASTWARD
THROUGH THE END OF THE PERIOD... WITH DIFFERENCES ARISING FROM
SHORTWAVES MOVING THROUGH THE FLOW DURING THIS TIME. WILL INTRODUCE
SLIGHT CHANCE POPS FOR FRIDAY.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
AS OF 750 AM SATURDAY...
GENERALLY VFR CONDITIONS EARLY THIS MORNING...ASIDE FROM VISIBILITY
RESTRICTIONS IN FOG AT KFAY...WILL LIKELY TRANSITION THROUGH A FEW
HOUR PERIOD OF MVFR/IFR CEILINGS BETWEEN 13-16Z AT ALL BUT THE TRIAD
TERMINALS...AS DIURNAL HEATING ACTS UPON AN INCREASINGLY MOIST AIR
MASS NEAR THE SURFACE. CONFIDENCE OF THIS SUB-VFR OCCURRENCE IS
ABOUT 50 PERCENT...AND MOST LIKELY AT KFAY. VFR CONDITIONS WITH A
BREEZY SSW WIND WILL OTHERWISE PREVAIL THROUGH THE THIS
EVENING...BEFORE WIDESPREAD LIFR/VLIFR STRATUS DEVELOPS BETWEEN 03-
07Z TONIGHT. A LITTLE PATCHY DRIZZLE MAY ALSO ACCOMPANY THE STRATUS.
LOOKING AHEAD: SHOWERS WILL BECOME NUMEROUS ACROSS THE AREA FROM
WEST TO EAST SUNDAY INTO SUNDAY NIGHT WITH WIDESPREAD SUB-VFR
CONDITIONS IN RAIN...POSSIBLY HEAVY AT TIMES...CONTINUING THROUGH
MONDAY AFTERNOON...AS A SLOW MOVING COLD FRONT PUSHES EAST THROUGH
THE AREA. VFR CONDITIONS ARE EXPECTED TO RETURN BY TUESDAY AND
CONTINUE THROUGH THE REMAINDER OF THE PERIOD.
&&
.CLIMATE...
AS OF 230 PM WEDNESDAY...
DAILY RECORDS FOR SATURDAY/SUNDAY DECEMBER 21/22 ARE AS FOLLOWS:
RALEIGH/DURHAM...
HIGHHI MIN
DECEMBER 21... 71 DEGREES...SET IN 196759 DEGREES...SET IN 1923
DECEMBER 22... 75 DEGREES...SET IN 196761 DEGREES...SET IN 2011
--------------------------------------------------------------------
GREENSBORO...
HIGHHI MIN
DECEMBER 21... 66 DEGREES...SET IN 192355 DEGREES...SET IN 1984
DECEMBER 22... 71 DEGREES...SET IN 192360 DEGREES...SET IN 2011
--------------------------------------------------------------------
FAYETTEVILLE...
HIGHHI MIN
DECEMBER 21... 77 DEGREES...SET IN 193160 DEGREES...SET IN 1923
DECEMBER 22... 75 DEGREES...SET IN 201160 DEGREES...SET IN 2011
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE
&&
$$
SYNOPSIS...26
NEAR TERM...77/26
SHORT TERM...30
LONG TERM...30
AVIATION...26/CBL
CLIMATE...RAH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
309 AM EST SAT DEC 21 2013
.SYNOPSIS...WARM SOUTHERLY FLOW AROUND BERMUDA HIGH PRESSURE WILL
CONTINUE THIS WEEKEND...AHEAD OF A MOISTURE-LADEN COLD FRONT THAT
WILL CROSS OUR REGION SUNDAY NIGHT AND MONDAY.
&&
.NEAR TERM /THROUGH SATURDAY NIGHT/...
AS OF 930 PM FRIDAY...
HIGH PRESSURE REMAINS ANCHORED OFF THE CAROLINA COAST THIS EVENING.
CIRRUS CONTINUES TO STREAM ACROSS THE AREA FROM THE SOUTHWEST AS
SOUTHWESTERLY UPPER LEVEL FLOW STRENGTHENS AHEAD OF A VIGOROUS STORM
SYSTEM TAKING SHAPE ACROSS THE SOUTHERN US. BASED ON SATELLITE
TRENDS...CIRRUS MAY THIN AT TIMES BUT A MAJORITY OF THE NIGHT WILL
BE MOSTLY CLOUDY. RETURN FLOW AROUND THE SURFACE HIGH MAKES STRATUS
A POSSIBILITY ONCE AGAIN...THOUGH FORECAST SOUNDINGS ARE NOT
SUGGESTING WIDESPREAD STRATUS DEVELOPMENT. THE 00Z RAOBS SHOW QUITE
A BIT MORE LOW-LEVEL MOISTURE AT KFFC THAN AT KCHS...WHICH IS WHERE
THE LOW-LEVEL FLOW IS ORIGINATING THIS EVENING. THE HRRR IS THE
MAIN MODEL SHOWING BETTER COVERAGE DEVELOPING OVER SC LATE TONIGHT
AND SPREADING ACROSS CENTRAL NC THROUGH MID-MORNING...BUT GIVEN THE
AMOUNT OF HIGH CLOUDS AND LACK OF MODEL AGREEMENT..EXPECT STRATUS
WILL BE PATCHY AND LATE TO DEVELOP. REGARDING TEMPS...CIRRUS HAS
HINDERED COOLING ALREADY THIS EVENING...AND UNLESS BETTER BREAKS IN
THE CIRRUS DEVELOP...LOWS WILL STRUGGLE TO FALL MUCH FURTHER THAN
THE UPPER 40S AND LOWER 50S IN MOST AREAS. -SMITH
SATURDAY AND SATURDAY NIGHT: THE AFOREMENTIONED COLD FRONT WILL
CONTINUE TO SLOWLY APPROACH THE REGION FROM THE WEST AS A SURFACE
WAVE OF LOW PRESSURE LIFTS FROM EASTERN TX INTO THE OHIO VALLEY
ALONG THE FRONT. WHILE LOW LEVEL CLOUD COVER SHOULD BE GREATER THAN
TODAY... AFTERNOON LOW LEVEL THICKNESS VALUES WILL INCREASE INTO THE
1380S ON SATURDAY AFTERNOON... SOME 20 METERS HIGHER THAN TODAY.
THIS SHOULD YIELD HIGH TEMPS NEAR STATISTICAL GUIDANCE (NEAR THE
WARM SIDE OF GUIDANCE)... AROUND 70 NW TO THE MID 70S
EAST/SOUTHEAST. LOWS WILL BE VERY WARM FOR THIS TIME OF YEAR WITH
AGAIN POSSIBLY SOME LOW CLOUDS. EXPECT LOWS WILL BE AROUND 60. BOTH
HIGHS AND LOWS WILL BE NEAR RECORD VALUES (RECORD HIGH MAX AND
RECORD HIGH MIN). SEE CLIMATE SECTION BELOW. WE COULD SEE SOME PRE-
FRONTAL SHOWERS AS INCREASING LOW LEVEL FLOW MAY HELP SUPPORT SOME
LIGHT SHOWERS ACROSS POINTS FROM OUR WESTERN PIEDMONT WESTWARD LATE
SATURDAY AFTERNOON INTO SATURDAY NIGHT. IF WE DO INDEED SEE ANY
PRECIP... EXPECT THE SHOWERS SHOULD BE LIGHT AND SPOTTY. FOR NOW
WILL KEEP POPS LOW FOR THIS TIME FRAME ACROSS THE WESTERN
PIEDMONT... AND NO POPS ELSEWHERE.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 305 AM SATURDAY...
DEEP SOUTHWESTERLY FLOW AHEAD OF AN APPROACHING COLD FRONT WILL TAP
INTO GULF MOISTURE... BRINGING PWS OF OVER 1.5 INCHES TO THE AREA
SUNDAY... NEAR MAX VALUES RECORDED FOR DECEMBER. HEAVY RAINFALL WILL
BE A POTENTIAL CONCERN... MAINLY OVER URBAN AREAS AS QPF REMAINS
SHORT OF FLASH FLOOD GUIDANCE AT THIS TIME. MID LEVEL LAPSE RATES
REMAIN WEAK... AND INSTABILITY LOW... SO THE SEVERE THREAT REMAINS
NEGLIGIBLE. ANY STORMS THAT DO DEVELOP MAY TAP IN TO THE STRONG 60-
65 KT LLJ AND BRING THE POTENTIAL FOR STRONG GUSTY WINDS ALONG WITH
HEAVY RAINFALL. SHEAR PROFILES WOULD BE SUPPORTIVE OF ROTATION...
HOWEVER THIS GOES STRONGLY AGAINST CLIMATOLOGY AND WITH THE
AFOREMENTIONED ENVIRONMENT... THIS IS A VERY LOW END THREAT. NEAR
RECORD HIGHS IN THE 70S.
THE COLD FRONT CROSSES THE AREA MONDAY AFTERNOON... MAKING IT TO THE
CAROLINA COAST BY 03Z TUES. HIGHS IN THE 60S. SHOWERS WILL END FROM
WEST TO EAST DURING THE EVENING HOURS. LOWS IN THE 30S WITH STRONG
COLD ADVECTION.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 307 AM SATURDAY...
UPPER LEVEL TROUGH MOVES OFF THE EAST COAST ON TUESDAY... AND THE
COLUMN DRIES SIGNIFICANTLY AS UPPER LEVEL FLOW BECOMES WESTERLY.
HIGH PRESSURE OVER THE MISSISSIPPI VALLEY ON TUESDAY WILL BUILD OVER
THE EAST COAST WEDNESDAY. HIGHS IN THE 40S ON TUESDAY WILL MODERATE
TOWARD NORMAL... IN THE 50S... WEDNESDAY THROUGH FRIDAY.
AN UPPER LEVEL TROUGH OVER CENTRAL US ON THURSDAY WILL MOVE EASTWARD
THROUGH THE END OF THE PERIOD... WITH DIFFERENCES ARISING FROM
SHORTWAVES MOVING THROUGH THE FLOW DURING THIS TIME. WILL INTRODUCE
SLIGHT CHANCE POPS FOR FRIDAY.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
AS OF 128 AM SATURDAY...
VFR CONDITIONS EARLY THIS MORNING MAY TRANSITION TO A PERIOD OF
MVFR/LIFR CEILINGS BETWEEN 11-16Z...AS DIURNAL HEATING ACTS UPON AN
INCREASINGLY MOIST AIR MASS NEAR THE SURFACE. CONFIDENCE OF THIS SUB-
VFR OCCURRENCE IS ABOUT 50 PERCENT...AND MOST LIKELY AT KFAY/
KRDU/KGSO. VFR CONDITIONS WITH A BREEZY SSW WIND WILL OTHERWISE
PREVAIL THROUGH THE TAF PERIOD.
LOOKING AHEAD: THE PROBABILITY OF LOW CLOUDS/STRATUS SHOULD CONTINUE
TO INCREASE SATURDAY NIGHT/SUNDAY MORNING WITHIN STRENGTHENING
MOISTURE TRANSPORT FEED FROM THE GULF...COMPLIMENTS OF A 50KT LLJ.
SHOWERS WILL BECOME MORE NUMEROUS ACROSS THE AREA FROM WEST TO EAST
LATE SUNDAY AFTERNOON AND INTO SUNDAY NIGHT WITH WIDESPREAD SUB-VFR
CONDITIONS IN RAIN...POSSIBLY HEAVY AT TIMES...CONTINUING THROUGH
MONDAY EVENING AS A SLOW MOVING COLD FRONT PUSHES EAST THROUGH THE
AREA. VFR CONDITIONS ARE EXPECTED TO RETURN BY TUESDAY AND CONTINUE
THROUGH THE REMAINDER OF THE PERIOD.
&&
.CLIMATE...
AS OF 230 PM WEDNESDAY...
DAILY RECORDS FOR SATURDAY/SUNDAY DECEMBER 21/22 ARE AS FOLLOWS:
RALEIGH/DURHAM...
HIGHHI MIN
DECEMBER 21... 71 DEGREES...SET IN 196759 DEGREES...SET IN 1923
DECEMBER 22... 75 DEGREES...SET IN 196761 DEGREES...SET IN 2011
--------------------------------------------------------------------
GREENSBORO...
HIGHHI MIN
DECEMBER 21... 66 DEGREES...SET IN 192355 DEGREES...SET IN 1984
DECEMBER 22... 71 DEGREES...SET IN 192360 DEGREES...SET IN 2011
--------------------------------------------------------------------
FAYETTEVILLE...
HIGHHI MIN
DECEMBER 21... 77 DEGREES...SET IN 193160 DEGREES...SET IN 1923
DECEMBER 22... 75 DEGREES...SET IN 201160 DEGREES...SET IN 2011
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE
&&
$$
SYNOPSIS...26
NEAR TERM...77/SMITH
SHORT TERM...30
LONG TERM...30
AVIATION...26/CBL
CLIMATE...RAH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
128 AM EST SAT DEC 21 2013
.SYNOPSIS...WARM SOUTHERLY FLOW AROUND BERMUDA HIGH PRESSURE WILL
CONTINUE THIS WEEKEND...AHEAD OF A MOISTURE-LADEN COLD FRONT THAT
WILL CROSS OUR REGION SUNDAY NIGHT AND MONDAY.
&&
.NEAR TERM /THROUGH SATURDAY NIGHT/...
AS OF 930 PM FRIDAY...
HIGH PRESSURE REMAINS ANCHORED OFF THE CAROLINA COAST THIS EVENING.
CIRRUS CONTINUES TO STREAM ACROSS THE AREA FROM THE SOUTHWEST AS
SOUTHWESTERLY UPPER LEVEL FLOW STRENGTHENS AHEAD OF A VIGOROUS STORM
SYSTEM TAKING SHAPE ACROSS THE SOUTHERN US. BASED ON SATELLITE
TRENDS...CIRRUS MAY THIN AT TIMES BUT A MAJORITY OF THE NIGHT WILL
BE MOSTLY CLOUDY. RETURN FLOW AROUND THE SURFACE HIGH MAKES STRATUS
A POSSIBILITY ONCE AGAIN...THOUGH FORECAST SOUNDINGS ARE NOT
SUGGESTING WIDESPREAD STRATUS DEVELOPMENT. THE 00Z RAOBS SHOW QUITE
A BIT MORE LOW-LEVEL MOISTURE AT KFFC THAN AT KCHS...WHICH IS WHERE
THE LOW-LEVEL FLOW IS ORIGINATING THIS EVENING. THE HRRR IS THE
MAIN MODEL SHOWING BETTER COVERAGE DEVELOPING OVER SC LATE TONIGHT
AND SPREADING ACROSS CENTRAL NC THROUGH MID-MORNING...BUT GIVEN THE
AMOUNT OF HIGH CLOUDS AND LACK OF MODEL AGREEMENT..EXPECT STRATUS
WILL BE PATCHY AND LATE TO DEVELOP. REGARDING TEMPS...CIRRUS HAS
HINDERED COOLING ALREADY THIS EVENING...AND UNLESS BETTER BREAKS IN
THE CIRRUS DEVELOP...LOWS WILL STRUGGLE TO FALL MUCH FURTHER THAN
THE UPPER 40S AND LOWER 50S IN MOST AREAS. -SMITH
SATURDAY AND SATURDAY NIGHT: THE AFOREMENTIONED COLD FRONT WILL
CONTINUE TO SLOWLY APPROACH THE REGION FROM THE WEST AS A SURFACE
WAVE OF LOW PRESSURE LIFTS FROM EASTERN TX INTO THE OHIO VALLEY
ALONG THE FRONT. WHILE LOW LEVEL CLOUD COVER SHOULD BE GREATER THAN
TODAY... AFTERNOON LOW LEVEL THICKNESS VALUES WILL INCREASE INTO THE
1380S ON SATURDAY AFTERNOON... SOME 20 METERS HIGHER THAN TODAY.
THIS SHOULD YIELD HIGH TEMPS NEAR STATISTICAL GUIDANCE (NEAR THE
WARM SIDE OF GUIDANCE)... AROUND 70 NW TO THE MID 70S
EAST/SOUTHEAST. LOWS WILL BE VERY WARM FOR THIS TIME OF YEAR WITH
AGAIN POSSIBLY SOME LOW CLOUDS. EXPECT LOWS WILL BE AROUND 60. BOTH
HIGHS AND LOWS WILL BE NEAR RECORD VALUES (RECORD HIGH MAX AND
RECORD HIGH MIN). SEE CLIMATE SECTION BELOW. WE COULD SEE SOME PRE-
FRONTAL SHOWERS AS INCREASING LOW LEVEL FLOW MAY HELP SUPPORT SOME
LIGHT SHOWERS ACROSS POINTS FROM OUR WESTERN PIEDMONT WESTWARD LATE
SATURDAY AFTERNOON INTO SATURDAY NIGHT. IF WE DO INDEED SEE ANY
PRECIP... EXPECT THE SHOWERS SHOULD BE LIGHT AND SPOTTY. FOR NOW
WILL KEEP POPS LOW FOR THIS TIME FRAME ACROSS THE WESTERN
PIEDMONT... AND NO POPS ELSEWHERE.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 250 PM FRIDAY...
STRONG WARM AIR ADVECTION CONTINUES AHEAD OF THE SLOWLY APPROACHING
COLD FRONT...WITH RECORD HIGH TEMPERATURES ON SUNDAY. SHOWER
ACTIVITY WILL BE GRADUALLY SPREADING INTO THE WESTERN PIEDMONT
THROUGH THE DAY...WITH CHANCE POPS IN THE EAST BY EVENING.
STRENGTHENING IN THE LOW LEVEL JET (>50KTS) AND FAVORABLE UPPER
DIFFLUENCE WILL BE OFFSET BY MEAGER INSTABILITY...WITH NEAR
NEGLIGIBLE CAPE SUNDAY...WILL CONTINUE ONGOING ISOLATED THUNDER.
HIGHS WILL REACH MID TO UPPER 70S OVER MOST OF THE AREA.
LIKELY TO CATEGORICAL POPS WILL BE THE RULE SUNDAY NIGHT AND MONDAY
AS THE FRONT MOVES SLOWLY ACROSS THE AREA. SIMILARLY...FORCING IS
STRONG IN THE FRONTAL ZONE...OFFSET BY WEAK MID LEVEL LAPSE RATES SO
WILL CONTINUE ISOLATED THUNDER...ALLOWING FOR STRONGER WORDING AS
THE SCENARIO APPROACHES AND THE TIMING CAN BE PINNED DOWN MORE
TIGHTLY. MINS WILL BE VERY MILD SUNDAY NIGHT...MID 50S TO LOWER
60S...GIVING A HEADSTART ON MONDAYS HIGHS...WHICH WILL PEAK IN THE
60S AS THE FRONT MOVES TO A POSITION EAST OF THE AREA BY MONDAY
AFTERNOON. SHOWERS WILL LINGER IN THE EAST THROUGH PERHAPS MIDNIGHT
MONDAY NIGHT...OTHERWISE COLD AIR ADVECTION WILL BE SURGING INTO THE
AREA MONDAY NIGHT...WITH SKIES CLEARING FROM THE WEST AND TEMPS
FALLING INTO THE 30S.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 25O PM FRIDAY...
CLEAR AND MUCH COOLER TUESDAY AND CHRISTMAS DAY AS HIGH PRESSURE
MIGRATES ACROSS THE OHIO VALLEY AND RIDGES DOWN THE ATLANTIC COAST.
HIGHS WILL BE IN THE LOW AND MID 40S BOTH DAYS. MORNING LOWS WILL BE
MOSTLY IN THE MID 20S CHRISTMAS MORNING.
THERE IS CONSIDERABLE UNCERTAINTY IN THE LATE WEEK PERIOD AS THE
UPCOMING COLD AIR DAMMING SCENARIO WILL ENCOURAGE DEVELOPMENT OF A
TROF ALONG THE COAST. THIS COULD LEAD TO SOME CYCLOGENESIS AND
UNSETTLED WEATHER IN THE EASTERN THIRD OF THE STATE BY FRIDAY. AT
THIS POINT AIRMASS MODIFICATION LOOK TO ALLOW HIGHS TO SNEAK BACK UP
TOWARDS THE CLIMATOLOGICAL RANGE OF UPPER 40S TO MID 50S THURSDAY
AND FRIDAY.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
AS OF 128 AM SATURDAY...
VFR CONDITIONS EARLY THIS MORING MAY TRANSITION TO A PERIOD OF
MVFR/LIFR CEILINGS BETWEEN 11-16Z...AS DIURNAL HEATING ACTS UPON AN
INCREASINGLY MOIST AIR MASS NEAR THE SURFACE. CONFIDENCE OF THIS SUB-
VFR OCCURENCE IS ABOUT 50 PERCENT...AND MOST LIKELY AT KFAY/
KRDU/KGSO. VFR CONDITIONS WITH A BREEZY SSW WIND WILL OTHERWISE
PREVAIL THROUGH THE TAF PERIOD.
LOOKING AHEAD: THE PROBABILITY OF LOW CLOUDS/STRATUS SHOULD CONTINUE
TO INCREASE SATURDAY NIGHT/SUNDAY MORNING WITHIN STRENGTHENING
MOISTURE TRANSPORT FEED FROM THE GULF...COMPLIMENTS OF A 50KT LLJ.
SHOWERS WILL BECOME MORE NUMEROUS ACROSS THE AREA FROM WEST TO EAST
LATE SUNDAY AFTERNOON AND INTO SUNDAY NIGHT WITH WIDESPREAD SUB-VFR
CONDITIONS IN RAIN...POSSIBLY HEAVY AT TIMES...CONTINUING THROUGH
MONDAY EVENING AS A SLOW MOVING COLD FRONT PUSHES EAST THROUGH THE
AREA. VFR CONDITIONS ARE EXPECTED TO RETURN BY TUESDAY AND CONTINUE
THROUGH THE REMAINDER OF THE PERIOD.
&&
.CLIMATE...
AS OF 230 PM WEDNESDAY...
DAILY RECORDS FOR SATURDAY/SUNDAY DECEMBER 21/22 ARE AS FOLLOWS:
RALEIGH/DURHAM...
HIGHHI MIN
DECEMBER 21... 71 DEGREES...SET IN 196759 DEGREES...SET IN 1923
DECEMBER 22... 75 DEGREES...SET IN 196761 DEGREES...SET IN 2011
--------------------------------------------------------------------
GREENSBORO...
HIGHHI MIN
DECEMBER 21... 66 DEGREES...SET IN 192355 DEGREES...SET IN 1984
DECEMBER 22... 71 DEGREES...SET IN 192360 DEGREES...SET IN 2011
--------------------------------------------------------------------
FAYETTEVILLE...
HIGHHI MIN
DECEMBER 21... 77 DEGREES...SET IN 193160 DEGREES...SET IN 1923
DECEMBER 22... 75 DEGREES...SET IN 201160 DEGREES...SET IN 2011
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE
&&
$$
SYNOPSIS...26
NEAR TERM...77/SMITH
SHORT TERM...26/13
LONG TERM...MLM
AVIATION...26/CBL
CLIMATE...RAH
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
551 AM EST SAT DEC 21 2013
.SYNOPSIS...
FRONT APPROACHES FROM THE WEST TODAY...PASSES AS COLD FRONT SUNDAY.
SNOW SHOWERS POSSIBLE MONDAY NIGHT INTO TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
SURFACE BOUNDARY HAS BEEN SHIFTING EAST SLOWLY THROUGH THE NIGHT AND
CURRENTLY RUNS FROM CENTRAL TEXAS NORTHEAST TO THE WESTERN SHORES
LAKE ERIE. ONE WAVE IS NEAR DETROIT AND LIFTING NE...DRIVING PRECIP
BISECTING OHIO. NEXT WAVE IS LIFTING INTO ARKANSAS WHICH IS MAYBE
JUST A BIT FASTER THAN THE LOWER RES MODELS...BUT REPRESENTED FAIRLY
WELL BY HIGHER RES MODELS LIKE HRRR AND RAP. SO TRENDED TOWARDS
THESE HIGHER RES MODELS FOR POPS THIS MORNING AS THE WAVE MOVES INTO
THE LOWER OHIO RIVER VALLEY WITH LIKELY POPS INTO SE OHIO. ANOTHER
WAVE IS STARTING TO TAKE SHAPE IN EASTERN TEXAS WHICH WILL DRIVE
ANOTHER AREA OF HIGHER POPS INTO SE OHIO TONIGHT. HAVE A BREAK
BETWEEN THE TWO WAVES...BUT STILL HAVE SLIGHT CHANCE POPS EAST AND
CHANCE POPS WEST THIS EVENING. THIS WILL ALSO BE THE WAVE THAT GETS
THE BOUNDARY MOVING EAST AGAIN...SO HAVE THE FRONT JUST WEST OF CWA
BORDER BY 12Z SUNDAY. NOT A WHOLE LOT OF INSTABILITY TODAY...BUT
850MB FLOW PUSHES 70-80KTS LATE THIS AFTERNOON INTO TONIGHT ACROSS
WESTERN CWA...MAINLY IN SE OHIO AND NE KENTUCKY. THIS MATCHES SPCS
SLIGHT RISK...AND WHILE THUNDER IS NOT EXPECTED...STRONGER SHOWERS
SHOULD STILL BE ABLE TO TAP INTO THIS AND PRODUCE SOME ENHANCED
OUTFLOW WINDS. WILL MENTION POTENTIAL FOR STRONG OUTFLOWS IN HWO FOR
SE OHIO AND NE KY COUNTIES. DO HAVE SLIGHT CHANCE OF THUNDER JUST
AHEAD OF THE FRONT EARLY SUNDAY MORNING...ANTICIPATING STRONG DYNAMIC
FORCING. STILL...NOT EXPECTING WIDESPREAD THUNDER...BUT A RUMBLE OR
TWO CANNOT BE RULED OUT.
PLACEMENT OF HIGHEST QPF STILL LOOKS TO STAY WEST OF CWA...JUST
CLIPPING NW CORNER LATE THIS AFTERNOON INTO TONIGHT...SO WILL NOT
MAKE ANY CHANGES TO FLOOD WATCH AT THIS POINT.
LITTLE TO NO CHANGE MADE TO HIGHS TODAY...GOING WELL ABOVE NORMAL
FOR THE WINTER SOLSTICE. DID WARM UP LOWS TONIGHT A COUPLE
DEGREES...AND WENT WITH A NON-DIURNAL TREND WITH NEARLY STEADY TEMPS
THROUGH THE EARLY MORNING OUT AHEAD OF THE COLD FRONT. NOT THAT ITS
AN OFFICIAL CLIMATE STATISTIC...BUT COULD BE CLOSE TO SETTING SOME
RECORD HIGH MINIMUMS.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
SFC LOW WILL BE QUICKLY PUSHING NORTHEAST FROM ROUGHLY CENTRAL
INDIANA TO THE EASTERN GREAT LAKES BTWN 12Z SUN AND 00Z MON.
ATTENDANT COLD FRONT ALSO PROGGED TO BE JUST OUTSIDE THE WESTERN
ZONES BY 12Z SUN AND WILL BE QUICKLY PUSHING ACROSS AS WELL. OVERALL
FORECAST GENERALLY STILL ON TRACK...BUT DID SLOW DOWN THE
PROGRESSION OF PRECIP ACROSS THE FORECAST AREA FROM WEST TO EAST BY
ABOUT TWO-THREE HOURS...WITH THE HIGHEST CHANCE OVER THE WEST ZONES
BY 12Z...CENTRAL ZONES BY 15Z...AND MOST PRECIP EAST OF THE I79
CORRIDOR BY 18Z. CONSENSUS OF MODEL OUTPUT STILL DEPICTING ABOUT
50KTS AT 925MB AND 70-80KTS AT 850MB. SPC HAS EXPANDED ITS SLIGHT
RISK AREA OF SEVERE THUNDERSTORMS TO INCLUDE MOST OF THE SE OHIO AND
NE KY COUNTIES. THE THREAT FOR A BRIEF SVR WIND GUST EXISTS FOR MOST
LOCATIONS PRETTY MUCH ANYWHERE ALONG AND WEST OF I79 SUNDAY MORNING
PRIMARILY AS THE MAIN CONVECTIVE LINE MARCHES ACROSS...BUT CERTAINLY
THE SE OHIO COUNTIES ARE MOST PRONE TO THIS POSSIBILITY AS THE ASSOC
LOWS AT 925MB AND 850MB MOVE NORTHEAST WITH THE SFC LOW. STILL
EXPECTING GENERALLY A HALF INCH OR SO OF PRECIP WITH SOME HIGHER
AMOUNTS AHEAD OF AND WITH THE FRONT. FOR MAX TEMPS...MOS GUIDANCE
CONTINUING TO INSIST ON LOWER 70S. WENT LOWER THAN THIS HOWEVER WITH
ONGOING CLOUDS AND PRECIP DURING THE MORNING HOURS AS COLD ADVECTION
IS BEGINNING...SHOULD STILL BE IN THE LOW/MID 60S. MAY ACTUALLY SEE
A FEW BREAKS IN THE CLOUDS ACROSS THE WESTERN ZONES BY 18Z-21Z...BUT
BY THIS TIME 925MB AND 850MB TEMPS CONTINUE TO LOWER TO READINGS
WHICH WOULD ONLY SUPPORT PERHAPS THE MID 60S ACROSS THOSE LOCATIONS.
PRECIP WILL WIND DOWN DURING THE AFTERNOON HOURS EVEN FOR THE
MOUNTAINS AS DEEP LAYER MOISTURE CONTINUES EASTWARD. ANOTHER
DEVELOPING WAVE ALONG THE FRONT HOWEVER WILL QUICKLY BRING A RETURN
TO PRECIP CHANCES MAINLY BTWN 06Z-12Z MON. THIS NEXT SFC WAVE WILL
SLOW/DELAY THE COLD PUSH OF AIR INTO THE AREA. IN FACT...HAVE HOURLY
TEMPS STILL IN THE LOWER 50S AROUND 06Z-08Z FOR LOWLANDS EAST OF
I79...WITH MUCH COOLER TEMPS ACROSS THE SE OHIO ZONES. AS THIS NEXT
SFC LOW ALSO PASSES TO THE NORTHEAST...WINDS WILL FINALLY COME
AROUND TO THE NORTHWEST ALLOWING FOR THE COLD AIR TO FILTER FULLY
INTO THE AREA. CODED UP SOMEWHAT OF A NON-DIURNAL TEMP CURVE FOR
MONDAY...WITH SOME MODEST RECOVERY OF TEMPS ACROSS THE FAR NW
ZONES...NEARLY STEADY TEMPS ACROSS THE CENTRAL AREAS...AND TEMPS
CONTINUING TO SLOWLY DROP DURING THE DAY ACROSS THE EASTERN
MOUNTAINS. SKIES SHOULD REMAIN MOSTLY CLOUDY TO CLOUDY FOR MOST WITH
THIS COLD ADVECTION...BUT AGAIN MAY SEE SOME LATE DAY BREAKS FOR THE
CENTRAL AND WEST ZONES.
A COLD NIGHT IS IN STORE FOR THE AREA MONDAY NIGHT/TUE MORNING.
SHOULD SEE MORE CLOUDS AND ANOTHER INCREASING CHANCE OF LIGHT
SNOW/FLURRIES...ESPECIALLY ACROSS THE NORTH...TOWARDS THE DAWN HOURS
TUE AS THE UPPER TROUGH FINALLY BEGINS TO SHIFT EASTWARD...WITH
TROUGH AXIS PROGGED TO BE LOCATED OVER LAKE HURON SOUTH INTO OHIO BY
12Z TUE. LOWERED MINS JUST A BIT INTO THE LOWER 20S WITH LOW
DEWPOINTS...BUT STAYED ABOVE THE LOWEST GUIDANCE WITH AFOREMENTIONED
CLOUD COVER AND A CONTINUED 10-15KT BREEZE IN THE BOUNDARY LAYER.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
SOME UPSLOPE SNOW POSSIBLE MONDAY NIGHT INTO TUESDAY AS COLD AIR
MOVES INTO THE REGION ON NORTHWEST FLOW. HIGH PRESSURE THEN BUILDS
IN FOR CHRISTMAS DAY. USED THE ECMWF MEAN FOR THURSDAY AND
FRIDAY...WHICH WOULD SHOW A FRONT MOVING THROUGH ON THURSDAY. BIG
QUESTION ON FRIDAY IS HOW MUCH COLD AIR RESIDES BEHIND THE FRONT AND
WHETHER ANY SNOW SHOWERS WILL BE ASSOCIATED WITH IT. WENT DRY FOR
NOW AS PER MEAN...BUT CONFIDENCE IS NOT HIGH.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
IN GENERAL...VFR EXPECTED THROUGH MUCH OF THE DAY AT THE TAF
SITES...HOWEVER COULD GET A PASSING MVFR CIG THIS MORNING. EXPECT
MVFR TO IFR ACROSS SE OHIO...CLOSER TO A NEARLY STALLED SURFACE
BOUNDARY. WILL ALSO HAVE BETTER CHANCE OF PRECIP TODAY ACROSS SE
OHIO...BEFORE THE CHANCES OF RAIN INCREASE FROM WEST TO EAST THROUGH
TONIGHT AS THE SURFACE BOUNDARY APPROACHES. WILL HAVE DROPS INTO
MVFR AND IFR IN THE WEST TOWARD THE END OF THE TAF PERIOD.
STRONG SW FLOW ALOFT WILL CONTINUE THROUGH THE TAF PERIOD WHICH WILL
RESULT IN SURFACE WINDS GUSTING INTO THE 20 TO 30 KT RANGE THIS
AFTERNOON AND TONIGHT. WITH FLOW REMAINING AT THE SURFACE...SHOULD
NOT REACH LLWS CRITERIA.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z SUNDAY...
FORECAST CONFIDENCE: MEDIUM TO HIGH.
ALTERNATE SCENARIOS: TIMING OF MVFR MAY VARY.
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 11 12 13 14 15 16 17 18 19 20 21 22
EST 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17
CRW CONSISTENCY H H H H H H H H H H H H
HTS CONSISTENCY M 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 H H H H H H H H H H H
PKB CONSISTENCY M H H H H H M M M H H H
CKB CONSISTENCY H H H H H H H H H H H H
AFTER 12Z SUNDAY...
IFR IN RAIN INTO SUNDAY. IFR POSSIBLE IN SNOW SHOWERS MONDAY NIGHT
INTO TUESDAY.
&&
.HYDROLOGY...
MODEL CONSENSUS SHOWS MAIN SWATH OF PRECIP JUST TO THE WEST OF THE
HSA. FOR THE WATCH AREA...EXPECT THE HEAVIEST RAINS TO OCCUR LATE
SATURDAY INTO SATURDAY NIGHT. 1 TO 2 INCHES ARE POSSIBLE WITH
LOCALLY HIGHER AMOUNTS. THE MAIN THREAT OF FLOODING IS FOR SMALL
STREAMS AND CREEKS...ESPECIALLY IN LOW LYING AND POOR DRAINAGE
AREAS. RISES ON THE MUSKINGUM ARE EXPECTED AS WELL. EVEN THOUGH THE
HEAVIEST RAINFALL IS EXPECTED TO FALL JUST OUTSIDE HSA...RUNOFF AND
STREAM FLOW WILL CONTINUE TO FLOW INTO THE WATCH AREA AND CAUSE
ELEVATED LEVELS ON STREAMS AND CREEKS.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...FLOOD WATCH THROUGH SUNDAY MORNING FOR OHZ066-067.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...RPY/MZ/50
NEAR TERM...MZ
SHORT TERM...50
LONG TERM...RPY
AVIATION...MZ
HYDROLOGY...MZ
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
440 AM EST SAT DEC 21 2013
.SYNOPSIS...
FRONT APPROACHES FROM THE WEST TODAY...PASSES AS COLD FRONT SUNDAY.
SNOW SHOWERS POSSIBLE MONDAY NIGHT INTO TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
SURFACE BOUNDARY HAS BEEN SHIFTING EAST SLOWLY THROUGH THE NIGHT AND
CURRENTLY RUNS FROM CENTRAL TEXAS NORTHEAST TO THE WESTERN SHORES
LAKE ERIE. ONE WAVE IS NEAR DETROIT AND LIFTING NE...DRIVING PRECIP
BISECTING OHIO. NEXT WAVE IS LIFTING INTO ARKANSAS WHICH IS MAYBE
JUST A BIT FASTER THAN THE LOWER RES MODELS...BUT REPRESENTED FAIRLY
WELL BY HIGHER RES MODELS LIKE HRRR AND RAP. SO TRENDED TOWARDS
THESE HIGHER RES MODELS FOR POPS THIS MORNING AS THE WAVE MOVES INTO
THE LOWER OHIO RIVER VALLEY WITH LIKELY POPS INTO SE OHIO. ANOTHER
WAVE IS STARTING TO TAKE SHAPE IN EASTERN TEXAS WHICH WILL DRIVE
ANOTHER AREA OF HIGHER POPS INTO SE OHIO TONIGHT. HAVE A BREAK
BETWEEN THE TWO WAVES...BUT STILL HAVE SLIGHT CHANCE POPS EAST AND
CHANCE POPS WEST THIS EVENING. THIS WILL ALSO BE THE WAVE THAT GETS
THE BOUNDARY MOVING EAST AGAIN...SO HAVE THE FRONT JUST WEST OF CWA
BORDER BY 12Z SUNDAY. NOT A WHOLE LOT OF INSTABILITY TODAY...BUT
850MB FLOW PUSHES 70-80KTS LATE THIS AFTERNOON INTO TONIGHT ACROSS
WESTERN CWA...MAINLY IN SE OHIO AND NE KENTUCKY. THIS MATCHES SPCS
SLIGHT RISK...AND WHILE THUNDER IS NOT EXPECTED...STRONGER SHOWERS
SHOULD STILL BE ABLE TO TAP INTO THIS AND PRODUCE SOME ENHANCED
OUTFLOW WINDS. WILL MENTION POTENTIAL FOR STRONG OUTFLOWS IN HWO FOR
SE OHIO AND NE KY COUNTIES. DO HAVE SLIGHT CHANCE OF THUNDER IN THE
GRIDS JUST AHEAD OF THE FRONT EARLY SUNDAY MORNING...ANTICIPATING
STRONG DYNAMIC FORCING. STILL...NOT EXPECTING WIDESPREAD
THUNDER...BUT A RUMBLE OR TWO CANNOT BE RULED OUT.
PLACEMENT OF HIGHEST QPF STILL LOOKS TO STAY WEST OF CWA...JUST
CLIPPING NW CORNER LATE THIS AFTERNOON INTO TONIGHT...SO WILL NOT
MAKE ANY CHANGES TO FLOOD WATCH AT THIS POINT.
LITTLE TO NO CHANGE MADE TO HIGHS TODAY...GOING WELL ABOVE NORMAL
FOR THE WINTER SOLSTICE. DID WARM UP LOWS TONIGHT A COUPLE
DEGREES...AND WENT WITH A NON-DIURNAL TREND WITH NEARLY STEADY TEMPS
THROUGH THE EARLY MORNING OUT AHEAD OF THE COLD FRONT. NOT THAT ITS
AN OFFICIAL CLIMATE STATISTIC...BUT COULD BE CLOSE TO SETTING SOME
RECORD HIGH MINIMUMS.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
SFC LOW WILL BE QUICKLY PUSHING NORTHEAST FROM ROUGHLY CENTRAL
INDIANA TO THE EASTERN GREAT LAKES BTWN 12Z SUN AND 00Z MON.
ATTENDANT COLD FRONT ALSO PROGGED TO BE JUST OUTSIDE THE WESTERN
ZONES BY 12Z SUN AND WILL BE QUICKLY PUSHING ACROSS AS WELL. OVERALL
FORECAST GENERALLY STILL ON TRACK...BUT DID SLOW DOWN THE
PROGRESSION OF PRECIP ACROSS THE FORECAST AREA FROM WEST TO EAST BY
ABOUT TWO-THREE HOURS...WITH THE HIGHEST CHANCE OVER THE WEST ZONES
BY 12Z...CENTRAL ZONES BY 15Z...AND MOST PRECIP EAST OF THE I79
CORRIDOR BY 18Z. CONSENSUS OF MODEL OUTPUT STILL DEPICTING ABOUT
50KTS AT 925MB AND 70-80KTS AT 850MB. SPC HAS EXPANDED ITS SLIGHT
RISK AREA OF SEVERE THUNDERSTORMS TO INCLUDE MOST OF THE SE OHIO AND
NE KY COUNTIES. THE THREAT FOR A BRIEF SVR WIND GUST EXISTS FOR MOST
LOCATIONS PRETTY MUCH ANYWHERE ALONG AND WEST OF I79 SUNDAY MORNING
PRIMARILY AS THE MAIN CONVECTIVE LINE MARCHES ACROSS...BUT CERTAINLY
THE SE OHIO COUNTIES ARE MOST PRONE TO THIS POSSIBILITY AS THE ASSOC
LOWS AT 925MB AND 850MB MOVE NORTHEAST WITH THE SFC LOW. STILL
EXPECTING GENERALLY A HALF INCH OR SO OF PRECIP WITH SOME HIGHER
AMOUNTS AHEAD OF AND WITH THE FRONT. FOR MAX TEMPS...MOS GUIDANCE
CONTINUING TO INSIST ON LOWER 70S. WENT LOWER THAN THIS HOWEVER WITH
ONGOING CLOUDS AND PRECIP DURING THE MORNING HOURS AS COLD ADVECTION
IS BEGINNING...SHOULD STILL BE IN THE LOW/MID 60S. MAY ACTUALLY SEE
A FEW BREAKS IN THE CLOUDS ACROSS THE WESTERN ZONES BY 18Z-21Z...BUT
BY THIS TIME 925MB AND 850MB TEMPS CONTINUE TO LOWER TO READINGS
WHICH WOULD ONLY SUPPORT PERHAPS THE MID 60S ACROSS THOSE LOCATIONS.
PRECIP WILL WIND DOWN DURING THE AFTERNOON HOURS EVEN FOR THE
MOUNTAINS AS DEEP LAYER MOISTURE CONTINUES EASTWARD. ANOTHER
DEVELOPING WAVE ALONG THE FRONT HOWEVER WILL QUICKLY BRING A RETURN
TO PRECIP CHANCES MAINLY BTWN 06Z-12Z MON. THIS NEXT SFC WAVE WILL
SLOW/DELAY THE COLD PUSH OF AIR INTO THE AREA. IN FACT...HAVE HOURLY
TEMPS STILL IN THE LOWER 50S AROUND 06Z-08Z FOR LOWLANDS EAST OF
I79...WITH MUCH COOLER TEMPS ACROSS THE SE OHIO ZONES. AS THIS NEXT
SFC LOW ALSO PASSES TO THE NORTHEAST...WINDS WILL FINALLY COME
AROUND TO THE NORTHWEST ALLOWING FOR THE COLD AIR TO FILTER FULLY
INTO THE AREA. CODED UP SOMEWHAT OF A NON-DIURNAL TEMP CURVE FOR
MONDAY...WITH SOME MODEST RECOVERY OF TEMPS ACROSS THE FAR NW
ZONES...NEARLY STEADY TEMPS ACROSS THE CENTRAL AREAS...AND TEMPS
CONTINUING TO SLOWLY DROP DURING THE DAY ACROSS THE EASTERN
MOUNTAINS. SKIES SHOULD REMAIN MOSTLY CLOUDY TO CLOUDY FOR MOST WITH
THIS COLD ADVECTION...BUT AGAIN MAY SEE SOME LATE DAY BREAKS FOR THE
CENTRAL AND WEST ZONES.
A COLD NIGHT IS IN STORE FOR THE AREA MONDAY NIGHT/TUE MORNING.
SHOULD SEE MORE CLOUDS AND ANOTHER INCREASING CHANCE OF LIGHT
SNOW/FLURRIES...ESPECIALLY ACROSS THE NORTH...TOWARDS THE DAWN HOURS
TUE AS THE UPPER TROUGH FINALLY BEGINS TO SHIFT EASTWARD...WITH
TROUGH AXIS PROGGED TO BE LOCATED OVER LAKE HURON SOUTH INTO OHIO BY
12Z TUE. LOWERED MINS JUST A BIT INTO THE LOWER 20S WITH LOW
DEWPOINTS...BUT STAYED ABOVE THE LOWEST GUIDANCE WITH AFOREMENTIONED
CLOUD COVER AND A CONTINUED 10-15KT BREEZE IN THE BOUNDARY LAYER.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
SOME UPSLOPE SNOW POSSIBLE MONDAY NIGHT INTO TUESDAY AS COLD AIR
MOVES INTO THE REGION ON NORTHWEST FLOW. HIGH PRESSURE THEN BUILDS
IN FOR CHRISTMAS DAY. USED THE ECMWF MEAN FOR THURSDAY AND
FRIDAY...WHICH WOULD SHOW A FRONT MOVING THROUGH ON THURSDAY. BIG
QUESTION ON FRIDAY IS HOW MUCH COLD AIR RESIDES BEHIND THE FRONT AND
WHETHER ANY SNOW SHOWERS WILL BE ASSOCIATED WITH IT. WENT DRY FOR
NOW AS PER MEAN...BUT CONFIDENCE IS NOT HIGH.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
EXPECT A MIX OF MVFR TO VFR CEILINGS THROUGH THE REST OF THE
NIGHT...WITH THE BEST CHANCE OF SUSTAINED MVFR ALONG AND WEST OF
THE OHIO RIVER. COULD ALSO GET ISOLATED SHOWERS ALONG AND WEST OF
THE OHIO RIVER THROUGH THE EARLY MORNING HOURS...BUT BULK OF THE
ACTIVITY WILL REMAIN WEST OF THE FORECAST AREA. SHOULD BE MAINLY
VFR TODAY...WITH A FEW LIGHT SHOWERS WEST. THE CHANCES OF RAIN
INCREASE THROUGH TONIGHT AS SURFACE BOUNDARY APPROACHES FROM THE
WEST WITH DIPS INTO MVFR POSSIBLE LATE.
STRONG SW FLOW ALOFT WILL CONTINUE THROUGH THE TAF PERIOD WHICH WILL
RESULT IN SURFACE WINDS GUSTING INTO THE 15 TO 20 KT RANGE. WITH
FLOW REMAINING AT THE SURFACE...SHOULD NOT REACH LLWS CRITERIA.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z SUNDAY...
FORECAST CONFIDENCE: MEDIUM TO HIGH.
ALTERNATE SCENARIOS: TIMING OF MVFR MAY VARY.
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 SAT 12/21/13
UTC 1HRLY 08 09 10 11 12 13 14 15 16 17 18 19
EST 1HRLY 03 04 05 06 07 08 09 10 11 12 13 14
CRW CONSISTENCY H H H H H H H H H H H H
HTS CONSISTENCY H H M M M M H H H H H H
BKW CONSISTENCY H H H H H H H H H H H H
EKN CONSISTENCY H H H H H H H H H H H H
PKB CONSISTENCY H H H H H H H H H H H H
CKB CONSISTENCY H H H H H H H H H H H H
AFTER 06Z SUNDAY...
IFR IN RAIN LATE SATURDAY NIGHT INTO SUNDAY. IFR POSSIBLE IN SNOW
SHOWERS MONDAY NIGHT INTO TUESDAY.
&&
.HYDROLOGY...
MODEL CONSENSUS SHOWS MAIN SWATH OF PRECIP JUST TO THE WEST OF THE
HSA. FOR THE WATCH AREA...EXPECT THE HEAVIEST RAINS TO OCCUR LATE
SATURDAY INTO SATURDAY NIGHT. 1 TO 2 INCHES ARE POSSIBLE WITH
LOCALLY HIGHER AMOUNTS. THE MAIN THREAT OF FLOODING IS FOR SMALL
STREAMS AND CREEKS...ESPECIALLY IN LOW LYING AND POOR DRAINAGE
AREAS. RISES ON THE MUSKINGUM ARE EXPECTED AS WELL. EVEN THOUGH THE
HEAVIEST RAINFALL IS EXPECTED TO FALL JUST OUTSIDE HSA...RUNOFF AND
STREAM FLOW WILL CONTINUE TO FLOW INTO THE WATCH AREA AND CAUSE
ELEVATED LEVELS ON STREAMS AND CREEKS.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...FLOOD WATCH FROM 7 AM EST THIS MORNING THROUGH SUNDAY MORNING
FOR OHZ066-067.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...RPY/MZ/50
NEAR TERM...MZ
SHORT TERM...50
LONG TERM...RPY
AVIATION...MZ
HYDROLOGY...MZ
AREA FORECAST DISCUSSION
NWS TULSA OK
935 PM CST SUN DEC 22 2013
...UPDATE...
.DISCUSSION...
UPDATED FORECAST WILL INCREASE CLOUD COVER THROUGH EARLY MORNING
WITH CLEARING IN LINE WITH LATEST RUC DATA. OVERNIGHT LOWS WERE
CONTINUED THOUGH EASTERN LOCATIONS HAVE MORE UNCERTAINTY PENDING
OVERNIGHT CLOUD COVER TRENDS.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 17 30 14 41 / 10 10 0 0
FSM 22 38 21 43 / 10 10 0 0
MLC 20 40 17 45 / 10 10 0 0
BVO 13 26 10 39 / 10 10 0 0
FYV 18 32 11 39 / 10 10 0 0
BYV 17 31 11 34 / 10 10 0 0
MKO 18 34 15 42 / 10 10 0 0
MIO 15 26 9 39 / 10 10 0 0
F10 18 35 15 43 / 10 10 0 0
HHW 23 44 22 47 / 10 10 0 0
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
SHORT TERM...07
AREA FORECAST DISCUSSION
NWS MEDFORD OR
857 AM PST SAT DEC 21 2013
.DISCUSSION...MOIST ONSHORE FLOW WILL PERSIST TODAY RESULTING IN
THICK CLOUD COVER OVER THE WEST SIDE. MUCH OF THE CLOUD COVER
WILL BE ALONG THE COAST AND BANKED UP AGAINST THE CASCADES AND
SISKIYOUS. THERE WILL ALSO BE SCATTERED LIGHT RAIN OR DRIZZLE,
ESPECIALLY NEAR THE MOUNTAINS AND FOOTHILLS. EXPECT A LITTLE
IMPROVEMENT THIS AFTERNOON AS THE AIR MASS BEGINS TO DRY OUT A
BIT...ESPECIALLY SOUTH OF THE UMPQUA DIVIDE. SO, WHILE NOT
CERTAIN, THERE IS THE OPPORTUNITY TO SEE A FEW SUNNY BREAKS HERE
IN MEDFORD TOWARD THE END OF THE DAY. VISIBLE IMAGERY IS SHOWING
BREAKS IN THE CLOUDS IN NORTHERN CALIFORNIA AND OVER THE EAST SIDE
THIS MORNING WITH SOME HIGH CLOUDINESS DUE TO MOUNTAIN WAVE ACTION
AND THE STRONG WINDS ALOFT. THIS SHOULD PERSIST TODAY. HIGHS WILL
BE MOSTLY IN THE 40S WITH SOME READINGS IN THE LOW 50S OVER ALONG
THE COAST AND IN NORTHERN CALIFORNIA. SPILDE
&&
.AVIATION...BASED ON THE 21/12Z TAF CYCLE.
SCATTERED LIGHT PRECIPITATION WILL CONTINUE THIS MORNING WITH THE
HIGHEST PROBABILITY OVER THE FOOTHILLS OF THE SOUTHERN OREGON
CASCADES AND THE CASCADES THEMSELVES. THIS HAS CREATED MOUNTAIN
OBSCURATIONS WITH MAINLY MVFR VSBYS AND CIGS, BUT WITH ISOLATED
IFR CONDITIONS AND ALSO AREAS OF VFR CIGS. CONDITIONS WILL BEGIN
TO IMPROVE AFTER LATE MORNING WITH CONTINUING MVFR CIGS MAINLY IN
SOUTHWEST OREGON. SVEN
&&
.PREV DISCUSSION... /ISSUED 403 AM PST SAT DEC 21 2013/
DISCUSSION...
WHILE TEMPERATURES HAVE WARMED TO ABOVE FREEZING THIS MORNING AT
MID AND UPPER ELEVATIONS AND TO THE LEE OF THE CASCADES, MOST
INTERIOR VALLEY LOCATIONS HAVE BEEN HOVERING BETWEEN 30 AND 35
DEGREES. VERY LITTLE PRECIPITATION APPEARS TO HAVE FALLEN SINCE
LAST EVENING AWAY FROM THE COAST AND UMPQUA BASIN, BUT SUSPECT
WHAT HAS ALONG WITH WHAT FELL DURING THE EVENING HAS LED TO SOME
ICY SPOTS IN THE STEEPER, MORE SHELTERED VALLEY LOCATIONS. A
SPECIAL WEATHER STATEMENT HAS BEEN ISSUED FOR PORTIONS OF THE
INTERIOR WEST SIDE AND AREAS EAST OF THE CASCADES HIGHLIGHTING
WHERE THERE MAY BE A GLAZE OF ICE THIS MORNING.
OTHERWISE, IT SHOULD BE NOTED THAT WINDS HAVE BEEN HOWLING IN THE
HIGHER MOUNTAINS TO INCLUDE THE CRATER LAKE RIM, MOUNT SHASTA, AND
PROBABLY ANYWHERE ABOVE ABOUT 6000 FEET. GUSTS IN THESE LOCATIONS
OVERNIGHT RANGED FROM AROUND 40 MPH ON THE CRATER LAKE RIM TO 99
MPH AT GREY BUTTE AT 8000 FEET ON MOUNT SHASTA. WINDS APPEAR TO
HAVE EASED A BIT BELOW 8000 FEET IN THE LAST HOUR, BUT EXPECT THEM
TO REMAIN STRONG AT HIGHER ELEVATIONS THROUGH THIS EVENING.
PRECIPITATION TODAY THROUGH THE WEEKEND WILL CONTINUE TO WANE WITH
TIME. ONSHORE FLOW TODAY WILL BE FOCUSED ON THE WEST SIDE, AND
PRECIPITATION WILL BE MOSTLY ALONG AND NEAR THE COAST AND COASTAL
MOUNTAINS, UMPQUA BASIN, AND FOOTHILLS OF THE CASCADES NORTH OF
ABOUT HIGHWAY 140. I HAVE SCALED BACK PRECIPITATION PROBABILITIES
AND AMOUNTS SOME TO BE MORE IN ACCORDANCE WITH THE 3KM HRRR MODEL,
AS IT SEEMS TO BE DEPICT WHAT HAS OCCURRED OVERNIGHT WELL.
THIS AFTERNOON THROUGH NEXT WEEKEND THE ONLY EXPECTED TRAVEL PROBLEM
WILL BE VALLEY FOG AND FREEZING FOG. A WEAK FRONTAL SYSTEM WILL
DISSIPATE AS IT ARRIVES MONDAY INTO TUESDAY, WITH ANOTHER POSSIBLY
DOING THE SAME NEXT WEEKEND. THUS, OUR COOL AND DRY DECEMBER LOOKS
AS IF IT WILL CONTINUE AS SUCH. BTL
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
CA...NONE.
PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL
10 AM PST SUNDAY FOR PZZ350-356-370.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 10 PM PST SUNDAY
FOR PZZ376.
$$
MAS/BTL/SBN
AREA FORECAST DISCUSSION
NWS MEDFORD OR
403 AM PST SAT DEC 21 2013
.DISCUSSION...
WHILE TEMPERATURES HAVE WARMED TO ABOVE FREEZING THIS MORNING AT
MID AND UPPER ELEVATIONS AND TO THE LEE OF THE CASCADES, MOST
INTERIOR VALLEY LOCATIONS HAVE BEEN HOVERING BETWEEN 30 AND 35
DEGREES. VERY LITTLE PRECIPITATION APPEARS TO HAVE FALLEN SINCE
LAST EVENING AWAY FROM THE COAST AND UMPQUA BASIN, BUT SUSPECT
WHAT HAS ALONG WITH WHAT FELL DURING THE EVENING HAS LED TO SOME
ICY SPOTS IN THE STEEPER, MORE SHELTERED VALLEY LOCATIONS. A
SPECIAL WEATHER STATEMENT HAS BEEN ISSUED FOR PORTIONS OF THE
INTERIOR WEST SIDE AND AREAS EAST OF THE CASCADES HIGHLIGHTING
WHERE THERE MAY BE A GLAZE OF ICE THIS MORNING.
OTHERWISE, IT SHOULD BE NOTED THAT WINDS HAVE BEEN HOWLING IN THE
HIGHER MOUNTAINS TO INCLUDE THE CRATER LAKE RIM, MOUNT SHASTA, AND
PROBABLY ANYWHERE ABOVE ABOUT 6000 FEET. GUSTS IN THESE LOCATIONS
OVERNIGHT RANGED FROM AROUND 40 MPH ON THE CRATER LAKE RIM TO 99
MPH AT GREY BUTTE AT 8000 FEET ON MOUNT SHASTA. WINDS APPEAR TO
HAVE EASED A BIT BELOW 8000 FEET IN THE LAST HOUR, BUT EXPECT THEM
TO REMAIN STRONG AT HIGHER ELEVATIONS THROUGH THIS EVENING.
PRECIPITATION TODAY THROUGH THE WEEKEND WILL CONTINUE TO WANE WITH
TIME. ONSHORE FLOW TODAY WILL BE FOCUSED ON THE WEST SIDE, AND
PRECIPITATION WILL BE MOSTLY ALONG AND NEAR THE COAST AND COASTAL
MOUNTAINS, UMPQUA BASIN, AND FOOTHILLS OF THE CASCADES NORTH OF
ABOUT HIGHWAY 140. I HAVE SCALED BACK PRECIPITATION PROBABILITIES
AND AMOUNTS SOME TO BE MORE IN ACCORDANCE WITH THE 3KM HRRR MODEL,
AS IT SEEMS TO BE DEPICT WHAT HAS OCCURRED OVERNIGHT WELL.
THIS AFTERNOON THROUGH NEXT WEEKEND THE ONLY EXPECTED TRAVEL PROBLEM
WILL BE VALLEY FOG AND FREEZING FOG. A WEAK FRONTAL SYSTEM WILL
DISSIPATE AS IT ARRIVES MONDAY INTO TUESDAY, WITH ANOTHER POSSIBLY
DOING THE SAME NEXT WEEKEND. THUS, OUR COOL AND DRY DECEMBER LOOKS
AS IF IT WILL CONTINUE AS SUCH. BTL
&&
.AVIATION...BASED ON THE 21/06Z TAF CYCLE.
A FEW WEAK DISTURBANCES WILL CONTINUE SCATTERED LIGHT PRECIPITATION
OVERNIGHT INTO EARLY SATURDAY MORNING. THE PROBABILITY OF
PRECIPITATION WILL BE HIGHEST OVER THE FOOTHILLS OF THE SOUTHERN
OREGON CASCADES AND THE CASCADES THEMSELVES. PRECIPITATION WILL FALL
MAINLY AS RAIN...INCLUDING AT THE TAF SITES. BUT THERE WILL BE LOCAL
FREEZING RAIN...MAINLY IN NARROW VALLEYS WHERE FREEZING AIR WILL
HAVE TROUBLE SCOURING OUT. THIS HAS CREATED MOUNTAIN OBSCURATIONS
WITH MAINLY MVFR VSBYS AND CIGS, BUT WITH ISOLATED IFR CONDITIONS
AND ALSO AREAS OF VFR CIGS. CONDITIONS WILL BEGIN TO IMPROVE AFTER
15Z SATURDAY MORNING WITH INCREASING COVERAGE OF VFR CIGS BUT WITH
AREAS OF MVFR CIGS PERSISTING THROUGH THE AFTERNOON...MAINLY IN
SOUTHWEST OREGON. DW
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
CA...NONE.
PACIFIC COASTAL WATERS...
- SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 10 AM PST SUNDAY
FOR PZZ350-356-370.
- SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 10 PM PST SUNDAY
FOR PZZ376.
$$
BTL/DW
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
549 AM CST SAT DEC 21 2013
.DISCUSSION...
SEE THE 12Z AVIATION DISCUSSION BELOW.
40
&&
.AVIATION...
THE FRONTAL BOUNDARY HAS MOVED EAST OF KCLL. THE RAP13 WAS DOING A
VERY GOOD JOB THIS MORNING. USED THE MODEL ALMOST EXCLUSIVELY FOR
KCLL AND INTERPOLATED ITS OUTPUT TO KUTS. THE MODEL WAVERS THE
FRONTAL BOUNDARY BACK NORTHWARD BY AROUND 15Z BEFORE PUSHING IT
SOUTHEASTWARD AGAIN AFTER 19Z. FURTHER TO THE SOUTH THE GUSTY
SOUTHERLY WINDS WILL PERSIST WITH THE FRONT NOT MAKING ITS WAY
THROUGH UNTIL ABOUT 19Z AT KCXO...AND THEN THE LATE AFTERNOON AT
THE METRO HOUSTON AIRPORTS SOUTHWARD TO THE COAST. IFR CONDITIONS
ARE MOST LIKELY FROM KIAH NORTHWARD. VFR IS EXPECTED TO DEVELOP
DURING THE AFTERNOON OVER KCLL AND KUTS...BUT NOT UNTIL BETWEEN
23Z AND 03Z ELSEWHERE.
40
&&
.PREV DISCUSSION... /ISSUED 436 AM CST SAT DEC 21 2013/
UPDATE...
A QUICK UPDATE TO ADJUST FOR TEMPS OVER THE NORTHWEST.
DISCUSSION...
THE RAP IS HANDLING TEMPS MUCH BETTER THAN ALL OTHER MODELS. FRONT
WENT THROUGH CLL AND RWV WITH TEMPS NOW IN THE LOWER 40S. HAVE
ADJUSTED HOURLY TEMP GRIDS TO REFLECT COOLER START OVER THE
NORTHWEST. 43
PREV DISCUSSION... /ISSUED 400 AM CST SAT DEC 21 2013/
DISCUSSION...
SHOWERS AND THUNDERSTORMS ARE INCREASING IN COVERAGE AND INTENSITY
THIS MORNING AS A STRONG UPPER LEVEL LOW OVER SOUTHERN NEW MEXICO
MOVES NE TOWARD CENTRAL OK. AT 3 AM...A STRONG SURFACE COLD FRONT
EXTENDED FROM NEAR LONGVIEW TO PALASTINE TO AUSTIN. TEMPS ARE 36
AT WACO AND 72 AT COLLEGE STATION. THE COMBINATION OF THE TROUGH
AND FRONT WILL SET THE STAGE FOR NUMEROUS SHRA/TSRA TODAY. SPC HAS
ALL OF SE TX OUTLOOKED IN SLIGHT RISK...BUT THE RISK IS
CONDITIONAL ON WHETHER CAPPING ERODES OR STAYS IN PLACE. SHEAR
VALUES ARE EXTREMELY HIGH BUT OTHER SEVERE WEATHER PARAMETERS ARE
FAIRLY TAME WITH CAPE VALUES LESS THAN 1000 J/KG. UPPER LEVEL
WINDS LOOK FAVORABLE AS SE TX WILL LIE IN 140 KT RRQ AROUND 18Z.
GFS FCST SOUNDING DATA IS CONSIDERABLY DRIER TODAY THAN YESTERDAY
AND ACTUALLY MATCHES UP WELL WITH THE 00Z CRP SOUNDING SO HAVE
SOME CONCERN THAT THE DRIER GFS SOLN MAY VERIFY. FCST SOUNDINGS
SHOW THE CAPPING INVERSION ERODING BETWEEN 12-15Z. FCST SOUNDINGS
ALSO SHOW A A FAIRLY DEEP DRY LAYER BETWEEN 850-700 MB WHICH NEVER
FULLY SATURATES. STILL...ITS HARD TO IGNORE THE NEGATIVE TILT TO
THE UPPER TROUGH...SFC BOUNDARY AND JET DYNAMICS. HAVE LEANED
TOWARD A BLEND OF THE HI- RES ARW...RAP...NAM 12 AND ECWMF FOR
TODAY. LOOKS LIKE SCT ACTIVITY WILL EVENTUALLY FORM A LINE OF
STORMS SOMEWHERE OVER THE CENTRAL PORTION OF THE CWA BETWEEN
15-18Z. THE LINE OF STORMS WILL THEN PUSH THROUGH THE REST OF THE
CWA BETWEEN 18-20Z. CAPPING IS LESS TOWARD THE NORTH AND EASTERN
PORTIONS OF THE CWA SO FEEL BEST THREAT FOR SEVERE WEATHER WILL BE
NORTHEAST OF A COLLEGE STATION TO HOUSTON TO GALVESTON LINE. THE
PRIMARY SEVERE WEATHER HAZARD WILL WILL BE DAMAGING WINDS AND
ISOLATED TORNADOES. IF CAPPING HOLDS...THE RISK FOR SEVERE WEATHER
WILL GREATLY DIMINISH. IT WILL BE INTERESTING TO SEE THE 12Z
SOUNDINGS.
A SECONDARY SURGE OF COLDER AIR WILL ARRIVE ON SUNDAY ALONG WITH
SOME MID LEVEL CLOUDINESS. HIGH TEMPS ON SUNDAY WILL BE ABOUT 20
DEGREES COOLER THAN TODAY. IT WILL STAY COOL FOR MUCH OF NEXT
WEEK AS THE UPPER FLOW REMAINS SOMEWHAT AMPLIFIED. ANOTHER S/WV
WILL DIG SSE ON WEDNESDAY AND THIS FEATURE WILL BRING SOME RAIN
BACK TO SOUTHEAST TEXAS LATE IN THE DAY AND OVERNIGHT. THE
CANADIAN IS THE MOST AGGRESSIVE WITH RAIN AND THE GFS WAS THE
DRIEST. THE ECMWF WAS A NICE COMPROMISE. ANOTHER FRONT IS EXPECTED
NEXT SATURDAY WHICH WILL REINFORCE THE ONGOING COOL CONDITIONS. 43
MARINE...
SEA FOG CONTINUED TO AFFECT GALVESTON BAY EARLY THIS MORNING. THE
FOG SHOULD LIFT LATER THIS MORNING AS SOUTHWESTERLY WINDS DEVELOP.
THE COOLER WATERS OF THE BAYS AND NEARSHORE GULF WATERS WILL KEEP
THE WIND SPEEDS DOWN THIS MORNING AS WELL. ADVISORY CONDITIONS WILL
PERSIST OVER THE OFFSHORE WATERS.
EXPECT WINDS WILL PICK UP OVER THE BAYS AND NEARSHORE WATERS TONIGHT
AS THE FRONT MOVES OFF THE COAST. OTHERWISE...ANOTHER BOUT OF
ADVISORY CONDITIONS ARE EXPECTED SUNDAY NIGHT AND MONDAY WITH THE
PASSAGE OF A STRONGER FRONT. THE MODELS THEN RETURN ONSHORE WINDS
BY LATE TUESDAY.
40
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 60 44 56 30 52 / 80 10 10 0 0
HOUSTON (IAH) 73 50 64 34 54 / 80 20 10 0 0
GALVESTON (GLS) 62 57 65 42 52 / 80 20 10 0 0
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 3 PM CST THIS AFTERNOON FOR THE
FOLLOWING ZONES: WATERS FROM FREEPORT TO THE MATAGORDA SHIP
CHANNEL 20 NM TO 60 NM...WATERS FROM HIGH ISLAND TO
FREEPORT 20 TO 60 NM.
DENSE FOG ADVISORY UNTIL 6 AM CST EARLY THIS MORNING FOR THE
FOLLOWING ZONES: GALVESTON BAY...WATERS FROM HIGH ISLAND TO
FREEPORT OUT 20 NM.
&&
$$
DISCUSSION...43
AVIATION/MARINE...40
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
436 AM CST SAT DEC 21 2013
.UPDATE...
A QUICK UPDATE TO ADJUST FOR TEMPS OVER THE NORTHWEST.
&&
.DISCUSSION...
THE RAP IS HANDLING TEMPS MUCH BETTER THAN ALL OTHER MODELS. FRONT
WENT THROUGH CLL AND RWV WITH TEMPS NOW IN THE LOWER 40S. HAVE
ADJUSTED HOURLY TEMP GRIDS TO REFLECT COOLER START OVER THE
NORTHWEST. 43
&&
.PREV DISCUSSION... /ISSUED 400 AM CST SAT DEC 21 2013/
DISCUSSION...
SHOWERS AND THUNDERSTORMS ARE INCREASING IN COVERAGE AND INTENSITY
THIS MORNING AS A STRONG UPPER LEVEL LOW OVER SOUTHERN NEW MEXICO
MOVES NE TOWARD CENTRAL OK. AT 3 AM...A STRONG SURFACE COLD FRONT
EXTENDED FROM NEAR LONGVIEW TO PALASTINE TO AUSTIN. TEMPS ARE 36
AT WACO AND 72 AT COLLEGE STATION. THE COMBINATION OF THE TROUGH
AND FRONT WILL SET THE STAGE FOR NUMEROUS SHRA/TSRA TODAY. SPC HAS
ALL OF SE TX OUTLOOKED IN SLIGHT RISK...BUT THE RISK IS
CONDITIONAL ON WHETHER CAPPING ERODES OR STAYS IN PLACE. SHEAR
VALUES ARE EXTREMELY HIGH BUT OTHER SEVERE WEATHER PARAMETERS ARE
FAIRLY TAME WITH CAPE VALUES LESS THAN 1000 J/KG. UPPER LEVEL
WINDS LOOK FAVORABLE AS SE TX WILL LIE IN 140 KT RRQ AROUND 18Z.
GFS FCST SOUNDING DATA IS CONSIDERABLY DRIER TODAY THAN YESTERDAY
AND ACTUALLY MATCHES UP WELL WITH THE 00Z CRP SOUNDING SO HAVE
SOME CONCERN THAT THE DRIER GFS SOLN MAY VERIFY. FCST SOUNDINGS
SHOW THE CAPPING INVERSION ERODING BETWEEN 12-15Z. FCST SOUNDINGS
ALSO SHOW A A FAIRLY DEEP DRY LAYER BETWEEN 850-700 MB WHICH NEVER
FULLY SATURATES. STILL...ITS HARD TO IGNORE THE NEGATIVE TILT TO
THE UPPER TROUGH...SFC BOUNDARY AND JET DYNAMICS. HAVE LEANED
TOWARD A BLEND OF THE HI- RES ARW...RAP...NAM 12 AND ECWMF FOR
TODAY. LOOKS LIKE SCT ACTIVITY WILL EVENTUALLY FORM A LINE OF
STORMS SOMEWHERE OVER THE CENTRAL PORTION OF THE CWA BETWEEN
15-18Z. THE LINE OF STORMS WILL THEN PUSH THROUGH THE REST OF THE
CWA BETWEEN 18-20Z. CAPPING IS LESS TOWARD THE NORTH AND EASTERN
PORTIONS OF THE CWA SO FEEL BEST THREAT FOR SEVERE WEATHER WILL BE
NORTHEAST OF A COLLEGE STATION TO HOUSTON TO GALVESTON LINE. THE
PRIMARY SEVERE WEATHER HAZARD WILL WILL BE DAMAGING WINDS AND
ISOLATED TORNADOES. IF CAPPING HOLDS...THE RISK FOR SEVERE WEATHER
WILL GREATLY DIMINISH. IT WILL BE INTERESTING TO SEE THE 12Z
SOUNDINGS.
A SECONDARY SURGE OF COLDER AIR WILL ARRIVE ON SUNDAY ALONG WITH
SOME MID LEVEL CLOUDINESS. HIGH TEMPS ON SUNDAY WILL BE ABOUT 20
DEGREES COOLER THAN TODAY. IT WILL STAY COOL FOR MUCH OF NEXT
WEEK AS THE UPPER FLOW REMAINS SOMEWHAT AMPLIFIED. ANOTHER S/WV
WILL DIG SSE ON WEDNESDAY AND THIS FEATURE WILL BRING SOME RAIN
BACK TO SOUTHEAST TEXAS LATE IN THE DAY AND OVERNIGHT. THE
CANADIAN IS THE MOST AGGRESSIVE WITH RAIN AND THE GFS WAS THE
DRIEST. THE ECMWF WAS A NICE COMPROMISE. ANOTHER FRONT IS EXPECTED
NEXT SATURDAY WHICH WILL REINFORCE THE ONGOING COOL CONDITIONS. 43
MARINE...
SEA FOG CONTINUED TO AFFECT GALVESTON BAY EARLY THIS MORNING. THE
FOG SHOULD LIFT LATER THIS MORNING AS SOUTHWESTERLY WINDS DEVELOP.
THE COOLER WATERS OF THE BAYS AND NEARSHORE GULF WATERS WILL KEEP
THE WIND SPEEDS DOWN THIS MORNING AS WELL. ADVISORY CONDITIONS WILL
PERSIST OVER THE OFFSHORE WATERS.
EXPECT WINDS WILL PICK UP OVER THE BAYS AND NEARSHORE WATERS TONIGHT
AS THE FRONT MOVES OFF THE COAST. OTHERWISE...ANOTHER BOUT OF
ADVISORY CONDITIONS ARE EXPECTED SUNDAY NIGHT AND MONDAY WITH THE
PASSAGE OF A STRONGER FRONT. THE MODELS THEN RETURN ONSHORE WINDS
BY LATE TUESDAY.
40
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 66 44 56 30 52 / 80 10 10 0 0
HOUSTON (IAH) 73 50 64 34 54 / 80 20 10 0 0
GALVESTON (GLS) 62 57 65 42 52 / 60 20 10 0 0
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 3 PM CST THIS AFTERNOON FOR THE
FOLLOWING ZONES: WATERS FROM FREEPORT TO THE MATAGORDA SHIP
CHANNEL 20 NM TO 60 NM...WATERS FROM HIGH ISLAND TO
FREEPORT 20 TO 60 NM.
DENSE FOG ADVISORY UNTIL 6 AM CST EARLY THIS MORNING FOR THE
FOLLOWING ZONES: GALVESTON BAY...WATERS FROM HIGH ISLAND TO
FREEPORT OUT 20 NM.
&&
$$
DISCUSSION...43
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1155 PM CST FRI DEC 20 2013
.AVIATION...
AN UPPER LEVEL DISTURBANCE OVER THE NORTHERN PART OF THE MEXICAN
STATE OF CHIHUAHUA IS MOVING EAST TOWARD WEST TEXAS AS OF 0530Z.
LIFT ASSOCIATED WITH THIS SYSTEM IS RESULTING IN A LARGE AREA OF
RAIN WITH SOME EMBEDDED THUNDERSTORMS MAINLY WEST OF A K0F2
/BOWIE/ TO KILE /KILLEEN/ LINE. IN THE MEANTIME A COLD FRONT HAS
NEARLY STALLED SOUTHEAST OF A LINE FROM KJDD /QUITMAN/ TO TEMPLE
/KTPL/. TEMPERATURES AT THE METROPLEX TAF SITES AT 11 PM /05Z/
WERE IN 33 TO 39 DEGREES...AND WILL FALL TO 32 TO 35 DEGREES
OVERNIGHT. SEVERAL ACARS/TAMDAR SOUNDINGS BETWEEN 04Z AND 05Z
SHOW A FEW HUNDRED FEET OF SUB-FREEZING AIR BETWEEN 1200 AND 1800
FEET WITH TEMPERATURES MAXING OUT IN THE MID 50S AROUND 3000
FEET. AS THE RAIN INCREASES OVERNIGHT...THE RELATIVELY WARM RAIN
DROPS SHOULD ALLOW TEMPERATURES TO ACTUALLY RISE A DEGREE OR TWO.
THUS HAVE KEPT ALL OF THE PRECIPITATION LIQUID IN THE TAFS. A FEW
THUNDERSTORMS ARE ALSO POSSIBLE OVERNIGHT INTO SATURDAY
MORNING...FOR NOW HAVE JUST PLACED A TEMPO TSRA FOR THE MOST
LIKELY TIME...10-14Z. IFR CONDITIONS WILL PREVAIL THROUGH MUCH OF
THE DAY SATURDAY...WITH A GRADUAL IMPROVEMENT TO MVFR BY MID
AFTERNOON AND SKIES SHOULD CLEAR DURING THE EVENING.
58
&&
.UPDATE...
THE LATEST WATER VAPOR LOOP SHOWS THE UPPER LOW CENTER TRUDGING
EAST AND GETTING CLOSER TO WEST TEXAS. LIFT IS ON THE INCREASE
ACROSS NORTH AND CENTRAL TEXAS...AND PRECIPITATION COVERAGE IS EXPECTED
TO RAMP UP OVER THE NEXT FEW HOURS. ISOLATED CONVECTION HAS BEGUN
IN THE WARM SECTOR WITH A FEW LIGHTNING STRIKES SHOWING UP NEAR
CANTON. MEANWHILE...THE SHALLOW ARCTIC AIRMASS HAS BARRELED
FARTHER SOUTH INTO CENTRAL TEXAS AND THE 32 DEGREE ISOTHERM HAD
DROPPED SOUTH OF POSSUM KINGDOM DURING THE PAST HOUR. WILL ADJUST
LOWS DOWNWARD ACCORDINGLY...WHILE ADDING A FEW MORE COUNTIES TO THE
RAIN/FREEZING RAIN MIX AREA WEST AND NORTHWEST OF THE DALLAS-FORT
WORTH METROPLEX...WITH LITTLE OR NO ACCUMULATIONS STILL EXPECTED.
30
&&
.PREV DISCUSSION... /ISSUED 411 PM CST FRI DEC 20 2013/
21Z SUBJECTIVE SURFACE ANALYSIS SHOWED A STRONG COLD FRONT IN
PLACE ALONG A LINE FROM PARIS TO DALLAS TO HAMILTON. THE
TEMPERATURE GRADIENT ALONG THIS BOUNDARY WAS QUITE IMPRESSIVE WITH
A 70 DEGREE TEMPERATURE THAT WAS OBSERVED AT GREENVILLE...A 49
DEGREE TEMPERATURE AT MCKINNEY AND A 39 DEGREE TEMPERATURE AT
DENTON. THIS FRONT WAS STILL MOVING SOUTHEAST AT 15 MPH AT THE
TIME OF THIS DISCUSSION. A 20Z AIRPLANE SOUNDING FROM DALLAS LOVE
FIELD INDICATED THAT THE FRONT WAS SHALLOW IN NATURE...WITH THE
FRONTAL INVERSION ONLY EXTENDING UP ABOUT 1500 FEET ABOVE GROUND
LEVEL. THE FRONT IS STILL EXPECTED TO STALL OUT OVER THE FAR
SOUTHEASTERN CWA THIS EVENING...IN RESPONSE TO CYCLOGENESIS
INITIATED BY THE APPROACH OF A POWERFUL UPPER LEVEL STORM SYSTEM.
THIS UPPER LEVEL STORM SYSTEM WAS OBSERVED OVER BAJA CALIFORNIA AT
20Z BASED ON WATER VAPOR SATELLITE IMAGERY. OUT AHEAD OF THIS
UPPER LEVEL STORM SYSTEM...WATER VAPOR SATELLITE IMAGERY SHOWED A
NICE CONTINUOUS BAND OF SUB-TROPICAL PACIFIC MOISTURE STREAMING
NORTHEAST OVER NORTHERN MEXICO AND THE SOUTH PLAINS. THE HIGH
TERRAIN OF NORTHERN MEXICO WILL SCOUR OUT ALL OF THE LOW TO MID-
TROPOSPHERIC MOISTURE ASSOCIATED WITH THIS SUBTROPICAL PLUME...BUT
THE MID TO UPPER LEVEL MOISTURE WILL CONTRIBUTE TO MOISTURE DEPTH
OVER THE REGION AS THE UPPER LEVEL STORM SYSTEM MOVES ACROSS THE
AREA TONIGHT INTO TOMORROW MORNING.
THROUGH TONIGHT...THE MOST TROUBLESOME FORECAST PROBLEM IN THE
SHORT TERM FORECAST IS THAT ALL FORECAST GUIDANCE IS DOING A
REMARKABLY POOR JOB RESOLVING THE STRENGTH OF THE SHALLOW COLD AIR
ASSOCIATED WITH/BEHIND THE COLD FRONT. WHILE ALL GUIDANCE IS DOING
A POOR JOB RESOLVING SURFACE TEMPERATURES NORTH OF THE COLD
FRONT...THE RAP IN PARTICULAR IS DIFFICULT TO PROCESS BECAUSE IT
CONTINUES TO INITIALIZE THE COLD AIR...BUT PERSISTENTLY BRINGS
SURFACE TEMPERATURES UP 5-7 DEGREES AT FORECAST HOUR 1 DESPITE
PERSISTENT COLD AIR ADVECTION AND CLOUD COVER. THIS WOULD BE MORE
OR LESS A NUISANCE IF THE TEMPERATURES HAD NO POTENTIAL TO HAVE AN
IMPACT ON PRECIPITATION TYPE IN THIS FORECAST. FOR INSTANCE...AT
BOWIE...THE 21Z OBSERVATION HAD A TEMPERATURE OF 32 DEG F. THE RAP
INITIALIZES THIS AT 34 DEGREES...WHICH IS NOT TOO FAR OFF...BUT
THEN GOES AHEAD TO FORECAST A TEMPERATURE OF 40 DEGREES BY 22Z.
WITH WIDESPREAD RAINFALL DEVELOPING OVER THE REGION RIGHT
NOW...AND EXPECTED TO PERSIST THIS EVENING INTO THE OVERNIGHT
HOURS...THIS ERROR IN RESOLVING NEAR SURFACE TEMPERATURES IS QUITE
PROBLEMATIC. THEREFORE...AT THIS TIME...WITH NO GUIDANCE AVAILABLE
ACTUALLY RESOLVING THE STRENGTH OF THIS COLD AIR...THE
PRECIPITATION TYPE FORECAST FOR TONIGHT WAS COMPLETED USING
OBSERVATIONAL TRENDS...RECENT FORECAST EVENTS AND INTUITION.
AT THIS TIME EXPECT THAT TEMPERATURES ALONG AND NORTHWEST OF A
GAINESVILLE TO GRAHAM LINE ARE MOST LIKELY TO FALL TO 32 DEGREES
THIS EVENING...LIKELY HOLDING STEADY THROUGH MUCH OF THE OVERNIGHT
HOURS. AS A RESULT...EVEN IF WE SEE RAIN AT 31 TO 32 DEGREES FOR
SEVERAL HOURS...THE CURRENT THINKING IS THAT WE WILL NOT SEE ANY
ICE ACCUMULATION...EXCEPT PERHAPS ON TREE TOPS OR THE TOPS OF
EXPOSED METAL SURFACES. THE REASONS FOR THIS ARE AS FOLLOWS:
1. BEFORE THE FRONT...WE HAVE EXPERIENCED A FEW DAYS OF ABOVE
NORMAL TEMPERATURES. GROUND/ROAD TEMPERATURES ARE WELL ABOVE
FREEZING WHICH WILL NOT ALLOW FOR ICE ACCUMULATION.
2. THE DEPTH OF THE ELEVATED WARM LAYER IS ALMOST 8 TIMES AS DEEP
AS THE DEPTH OF THE COLD/SUB-FREEZING LAYER. RAIN FALLING IN THIS
ENVIRONMENT WILL LIKELY HAVE A TEMPERATURE ABOVE FREEZING WHEN IT
REACHES THE SURFACE. THAT IS THE TEMPERATURE OF THE FALLING RAIN
DROPS ARE LIKELY TO BE ABOVE FREEZING...THIS IS ALSO NOT CONDUCIVE
TO ICE ACCUMULATION.
3. ALL GUIDANCE INDICATES PERSISTENT WARM AIR ADVECTION THROUGH
12Z SATURDAY ABOVE THE COLD FRONTAL INVERSION. THE WARM LAYER IS
VERY LIKELY TO MAINTAIN ITS DEPTH AND STRENGTH...WHILE RELATIVELY
WARM RAIN DROPS MAY ACTUALLY SHRINK THE DEPTH OF THE SHALLOW COLD
AIR OVERNIGHT.
AS A RESULT...WILL NOT BE HIGHLIGHTING FREEZING RAIN IN THE
FORECAST AT THIS TIME...DESPITE THE SURFACE OBSERVATION AT BOWIE
AT 32 DEGREES SEEMINGLY SHOWING AN ICE STORM ON OUR DOORSTEP. IT
LOOKS LIKE THE DEPTH OF THE COLD AIR WILL ONLY SUPPORT ICE
ACCUMULATION FARTHER NORTH...WELL INTO OKLAHOMA BASED ON
OBSERVATIONAL ANALYSIS AND DFW AREA AIRCRAFT SOUNDINGS.
DESPITE ALL THAT HAS BEEN DISCUSSED ABOUT THE SHALLOW COLD AIR
PROBLEM...THERE WERE ACTUALLY NO SIGNIFICANT CHANGES MADE TO THE
PREVIOUS FORECAST WHICH REMAINS LARGELY ON TRACK. THE BAJA UPPER
LEVEL LOW IS STILL EXPECTED TO MOVE OVER THE SOUTH PLAINS TOMORROW
MORNING...SPREADING STRONG LARGE SCALE FORCING FOR ASCENT OVER THE
REGION TONIGHT THROUGH TOMORROW MORNING. NEARLY ALL GUIDANCE
INDICATES THAT THE UPPER LOW WILL BECOME INCREASINGLY NEGATIVELY
TILTED AS IT MOVES OUT OVER TEXAS...DEEPENING AS IT MOVES OVER THE
CWA. THE STRONGEST FORCING FOR ASCENT LOOKS TO MOVE OVER THE CWA
IN THE 09 TO 15Z TIME FRAME...WHICH SHOULD ALSO REPRESENT OUR
WINDOW FOR THE BEST COVERAGE AND HEAVIEST PRECIPITATION RATES
DURING THIS EVENT.
FOR THIS EVENING...THE COLD FRONT PUSHING SOUTH THROUGH MOST OF
THE CWA WILL SIMPLY HELP TO STEEPEN LOW-LEVEL ISENTROPIC SURFACES
AS CYCLOGENESIS RAMPS UP NEAR DEL RIO RESULTING IN AN INCREASE OF
THE STRENGTH OF THE LOW TO MID-LEVEL WIND FIELD. THIS SHOULD
RESULT IN A SPREAD OF THE COVERAGE OF ONGOING RAIN SHOWER
ACTIVITY FROM WEST TO EAST ACROSS THE CWA. AS THE UPPER LEVEL LOW
APPROACHES...ASSUMING IT BECOMES MORE NEGATIVELY TILTED AS
ADVERTISED...WE SHOULD SEE AN ENHANCEMENT OF MID-LEVEL LAPSE RATES
WITH SOME UPPER-LEVEL COLD AIR ADVECTION OVER THE PERSISTENT LOW-
LEVEL WARM AIR ADVECTION REGIME. THIS WILL RESULT IN AN INCREASED
CHANCE OF ISOLATED THUNDERSTORMS EMBEDDED IN THE RAIN SHOWER
ACTIVITY FROM SUNSET TO MIDNIGHT. ALL OF THIS ACTIVITY SHOULD
REMAIN ELEVATED IN NATURE...AND POSES VERY LITTLE SEVERE WEATHER
THREAT AS A RESULT. RAINFALL RATES WILL BE ENHANCED...AND
THEREFORE SOME LOCALIZED HEAVY RAINFALL IS POSSIBLE.
AFTER MIDNIGHT...AS MENTIONED ABOVE...THE BEST LARGE SCALE FORCING
FOR ASCENT IS EXPECTED TO BUILD ACROSS THE CWA FROM WEST TO EAST
DURING THIS TIME RESULTING IN THE STRONGEST AND MOST WIDESPREAD
CONVECTION AND PRECIPITATION FOR THE REGION. BASED ON THE POSITION
OF THE COLD FRONT AT THAT TIME...WE DO HAVE A WINDOW FOR SURFACE
BASED SEVERE STORMS BASED ON CONVECTIVE PARAMETERS ADVERTISED IN
THE MAJORITY OF GUIDANCE. LOCATIONS ALONG AND SOUTHEAST OF
WHEREVER THE COLD FRONT STALLS OUT WOULD BE THE ONLY LOCATIONS
WHERE SURFACE BASED SEVERE STORMS WOULD BE POSSIBLE. FORECAST
CONVECTIVE PARAMETERS INDICATED SURFACE BASED CAPE VALUES OF
AROUND 1000 J/KG WITH 0-3 KM CAPE VALUES OF AROUND 100 J/KG AND
DEEP LAYER SHEAR VALUES IN EXCESS OF 50 KTS.
THESE VALUES ARE SUPPORTIVE OF A LOW-TOPPED SUPER CELLULAR STORM
MODE...WHICH COULD RESULT IN LARGE HAIL...DAMAGING WIND OR
ISOLATED TORNADOES. THIS THREAT IS MODERATED BY STRONG FORCING
WHICH MAY MAKE AN ISOLATED STORM MODE DIFFICULT TO REALIZE...AND
STRONG CLOUD LEVEL WINDS THAT WILL LIKELY TAKE STORMS THAT DEVELOP
ALONG THE FRONT...OVER/NORTH OF THE FRONT SHORTLY AFTER
INITIATION. REGARDLESS...WILL BE WATCHING FOR WHERE THE FRONT
STALLS OUT TONIGHT AS LOCATIONS NEAR AND TO THE SOUTHEAST OF THE
BOUNDARY ARE THE MOST LIKELY TO SEE SEVERE WEATHER. FURTHER
NORTHWEST...STRONG STORMS REMAIN POSSIBLE...HOWEVER EVEN ELEVATED
SUPERCELLS ARE ONLY GOING TO PROVIDE A THREAT FOR MARGINALLY
SEVERE HAIL...SO THE OVERALL SEVERE WEATHER THREAT NORTHWEST OF
THE FRONT DIMINISHES GREATLY.
FOR ANYWHERE ACROSS NORTH TEXAS...LOCALLY HEAVY RAINFALL IS
POSSIBLE WHICH MAY RESULT IN SOME LOCALIZED FLASH FLOODING ISSUES
OVER THE NEXT 24 HRS. WITH THE SUB-TROPICAL PACIFIC MOISTURE FEED
IN PLACE...AND LOW-LEVEL WARM MOIST ADVECTION EXPECTED TO RAMP UP
IN INTENSITY OVER THE SHALLOW COLD FRONT...NEARLY ALL GUIDANCE
INDICATES THAT PWAT VALUES WILL BE UP AROUND 1.5 INCHES ACROSS
NORTH AND CENTRAL TEXAS AS THE UPPER LOW SPREADS STRONG FORCING
OVER THE REGION. 1.5 INCH PRECIPITABLE WATER VALUES RANK AS PLUS 3
STANDARD DEVIATION FOR NORTH TEXAS AT THIS TIME OF YEAR. THIS
EXCEPTIONALLY DEEP MOISTURE COMBINED WITH FAVORABLE DYNAMICS FOR
WIDESPREAD PRECIPITATION SUPPORT A LOCALIZED HEAVY RAINFALL THREAT
WITH AN ATTENDANT LOCALIZED FLOODING THREAT TONIGHT INTO TOMORROW
MORNING. DID NOT ISSUE A FLASH FLOOD WATCH AT THIS TIME BECAUSE
OUR PRIMARY WINDOW FOR HEAVY RAINFALL IS ONLY EXPECTED TO BE ON
THE ORDER OF 6 HOURS OR SO. IF STRONG FORCING WAS EXPECTED TO BE
IN PLACE FOR A LONGER PERIOD OF TIME...THE THREAT OF WIDESPREAD
FLOODING WOULD BE MUCH GREATER AND A WATCH WOULD HAVE BEEN ISSUED.
AT THIS TIME THE THREAT OF FLOODING IS EXPECTED TO REMAIN
LOCALIZED AND MAINLY CONFINED TO LOW LYING/COMMONLY FLOODED AREAS.
HEAVY PRECIPITATION IS EXPECTED TO COME TO AN END FROM SOUTHWEST
TO NORTHEAST SATURDAY AFTERNOON AS A STRONG MID-LEVEL DRY SLOT
PUNCHES OVER THE REGION. LIGHT RAIN MAY PERSIST ACROSS THE AREA
SATURDAY AFTERNOON...BUT EVEN THIS WILL BE SCOURED OUT BY SUNSET.
REMAINDER OF THE FORECAST...NO SIGNIFICANT CHANGES WERE MADE TO
THE PREVIOUS FORECAST AS MOST OF THE ACTIVITY IN THE FORECAST IS
IN THE FIRST 24 HOURS. HIGHLIGHTS OF THE REMAINDER OF THE FORECAST
INCLUDE:
1. ADDED A MENTION OF SPRINKLES/LIGHT RAIN TO THE FORECAST ALONG
THE COLD FRONT THAT IS EXPECTED TO PUSH SOUTH THROUGH THE CWA ON
SUNDAY MORNING. WILL HAVE TO WATCH TEMPERATURES CLOSELY SUNDAY
MORNING AS THIS FRONT ROLLS THROUGH...HOWEVER ALL GUIDANCE
INDICATES TEMPERATURES JUST ABOVE FREEZING WITH THIS VERY LIGHT
PRECIPITATION.
2. WE SHOULD BE DRY EARLY NEXT WEEK...LEADING UP TO CHRISTMAS DAY.
TEMPERATURES WILL SLOWLY WARM THROUGH CHRISTMAS...ALTHOUGH HIGHS
ARE EXPECTED TO REMAIN BELOW NORMAL THROUGH THE WEEK AHEAD.
3. AN UPPER LEVEL STORM SYSTEM MAY RESULT IN SCATTERED RAIN
SHOWERS ACROSS THE REGION ON CHRISTMAS DAY. AT THIS TIME
TEMPERATURES ARE EXPECTED TO BE WELL ABOVE FREEZING...SO NO
SIGNIFICANT IMPACTS ARE EXPECTED AT THIS TIME.
CAVANAUGH
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 36 47 36 48 29 / 100 100 10 10 5
WACO, TX 42 62 37 50 30 / 80 100 10 10 5
PARIS, TX 41 45 36 47 26 / 100 100 10 10 10
DENTON, TX 33 44 34 47 26 / 100 100 10 10 5
MCKINNEY, TX 35 44 35 46 25 / 100 100 10 10 5
DALLAS, TX 37 46 38 48 30 / 100 100 10 10 5
TERRELL, TX 41 47 37 47 28 / 100 100 10 10 5
CORSICANA, TX 46 54 39 48 30 / 80 100 10 10 5
TEMPLE, TX 41 63 39 52 31 / 80 100 10 10 5
MINERAL WELLS, TX 31 49 34 48 24 / 100 90 10 10 5
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
58/30
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1135 PM CST FRI DEC 20 2013
.DISCUSSION...
UPDATED AVIATION SECTION.
&&
.AVIATION...
AGAIN CHALLENGING 06Z TAF PACKAGE. CURRENTLY SURFACE ANALYSIS
SHOWS SURFACE LOW DEVELOPING OVER CENTAL TX. AN AREA OF RAIN WITH
EMBEDDED THUNDERSTORMS IS ASSOCIATED WITH THIS LOW AND FRONTAL
ZONE. WATER VAPOR SHOWING UPPER LOW AND ASSOCIATED JET MAKING ITS
WAY INTO WEST TEXAS. ANOTHER AREA OF RAIN WITH EMBEDDED THUNDER
WAS ASSOCIATED WITH THIS FEATURE. EAST OF THESE TWO RAIN AREAS
WERE SOME VERY LIGHT SHOWERS OCCURRING AS MOISTURE ADVECTS IN OFF
THE GULF AND WITH A SMALL AMOUNT OF CAPE BELOW THE CAPPING
INVERSION.
TAKING ALL THESE SYSTEMS INTO ACCOUNT...EXPECT CAPPING
INVERSION TO KEEP PRECIPITATION INITIALLY IN THE FORM OF VERY LIGHT
RAIN SHOWERS...BUT WITH COOLING ALOFT AND LIFT ASSOCIATED WITH
APPROACHING UPPER LOW...GREATER THREAT OF HEAVIER RAIN AND
THUNDERSTORMS TO FIRST REACH CLL AROUND DAYBREAK...THE HOUSTON
AREA AIRPORTS BETWEEN MID MORNING AND EARLY AFTERNOON....AND
GALVESTON WITH SURFACE FRONTAL PASSAGE MID AFTERNOON. SITUATION IS
MOST COMPLEX FOR CLL AS FIRST RAIN AREA WITH EMBEDDED THUNDER
COULD BRUSH THAT AREA IN THE PRE DAWN HOURS. SOME POTENTIAL FOR
GUSTY WINDS WITH THE STRONGER STORMS AS LOW LEVEL JET VERY STRONG.
CEILINGS MAINLY MVFR BUT WITH AREAS OF OR TEMPO IFR AS ARE
CURRENTLY OCCURING. 46
&&
.PREV DISCUSSION... /ISSUED 910 PM CST FRI DEC 20 2013/
UPDATE...
THE ONLY CHANGE ON THIS SHIFT WAS TO ADJUST SHORT TERM POPS/WX TO
BETTER COME IN-LINE WITH ONGOING TRENDS. DURING THE 8 PM HOUR...THE
COLD FRONT IS WORKING ITS WAY SOUTHWARD AND NOW PUSHING INTO THE
SOUTHERN COUNTIES OF DFW`S CWA. DOWNSTREAM OF THIS MAIN BOUNDARY...
VERY LIGHT RAIN SHOWERS OR DRIZZLE AFFECTING OUR FA...MOVING NORTH
WITHIN A VERY PERSISTENT SWATH OF 40 KT JUST-OFF-THE-SURFACE SOUTHERLY
(LLJ) FLOW. A VERY WARM AND MOIST OVERNIGHT WITH SEA FOG LOWERING
MARITIME VISIBILITIES TO UNDER A COUPLE OF MILES AT TIMES...LOCALLY
DENSE AT A MILE OR UNDER ESPECIALLY IF NEARSHORE SOUTHERLIES BACK
A BIT MORE EASTERLY WITH TIME. MINIMUM TEMPERATURES WILL BE A
DEGREE OR TWO OFF 70 F...WITH SIGNIFICANTLY GREATER CONVECTIVE
CHANCES FROM AROUND 21/09Z ONWARD OVER THE NORTHERN FORECAST
AREA. THE HRRR DISPLAYING THE FORMATION OF MORE DISCRETE CELLS
FROM SHORTLY AFTER MIDNIGHT THROUGH SUNRISE. OUR MOISTENED DOWNSTREAM
ENVIRONMENT IS HIGHLY SHEARED AFFORDING HIGH HELICITY AND
SIGNALING THAT MANY UPDRAFTS WILL ROTATE. SPC HAS THE NORTHERN
THIRD OF THE CWA HIGHLIGHTED IN SLIGHT RISK TO ACCOUNT FOR THIS
EARLY MORNING THROUGH EARLY AFTERNOON THREAT FOR STRONG
CELLS...POSSIBLY WITHIN A BROKEN WEST-MOVING-EAST QLCS...REACHING
SEVERE LIMITS. DAMAGING WINDS AND TORNADOES WILL BE THE MAIN
THREATS THROUGH MID-SATURDAY. 31
PREV DISCUSSION... /ISSUED 554 PM CST FRI DEC 20 2013/
DISCUSSION...
UPDATED AVIATION FOR OOZ TAFS.
AVIATION...
TRICKY FORECAST WITH CEILING HEIGHTS OVERNIGHT...AND TIMING OF THE
THUNDERSTORM THREAT BEING THE BIGGEST CHALLENGES. ALREADY SEEING
CIGS IN THE 1000 TO 1200 FOOT RANGE SOME LOCATIONS. GLS SOCKED IN
WITH SEA FOG AND HALF MILE VISIBILITY. RADAR SHOWING LIGHT RETURNS
INCREASING ASSOCIATED WITH VERY LIGHT SHOWERS OR SPRINKLES.
OVERNIGHT AM IN GENERAL GOING WITH MVFR CIGS PREVAILING...NEAR
CURRENT LEVELS BUT THINK THERE WILL BE A WINDOW OF CIGS BLO 1000
FEET AT MOST AIRPORTS AND HAVE INDICATED THAT WITH A TEMPO GROUP
OVERNIGHT MOST SITES. THUNDERSTORM THREAT WILL BE SATURDAY MORNING
FOR CLL AND UTS...MORE MIDDAY AND EARLY AFTERNOON FOR CXO AND IAH
AND AFTERNOON FOR HOU...SGR...LBX AND GLS. MOST LIKELY SCENARIO
WILL BE NUMEROUS LIGHT SHOWERS UNDERNEATH THE CAP BEFORE
THEN...THEN THE DEVLOPMENT OF A LINE OF STORMS THAT WILL MOVE
QUICKLY OVER THE AREA. THREAT SHOULD BE EAST OF THE TAF SITES BY
LATE TOMORROW AFTERNOON. 46
PREV DISCUSSION... /ISSUED 406 PM CST FRI DEC 20 2013/
SLIGHT RISK OF SEVERE WEATHER TONIGHT INTO SATURDAY...
DISCUSSION...
SFC ANALYSIS HAS COLD FRONT PUSHING THROUGH DFW METROPLEX HEADED
TOWARDS A TYLER/WACO LINE. FRONT SHOULD PUSH CLOSE TO A COLLEGE
STATION TO CROCKETT LINE TONIGHT BUT LIKELY STALL JUST NORTH.
MOISTURE HAS DEEPENED WITH SFC DEWPOINTS IN THE 70S. SEA FOG MAY
BE AN ISSUE ALONG THE COAST SO WILL HAVE ANOTHER DENSE FOG
ADVISORY FOR THE COAST TONIGHT. SHOWERS SHOULD INCREASE OVERNIGHT
WITHIN MAY MOISTURE AXIS THROUGH THE AREA. SO REALLY NO CHANGES IN
THE FORECAST THROUGH TONIGHT.
UPPER AIR ANALYSIS AND WATER VAPOR IMAGERY SHOW STRONG UPPER LOW
MOVING ACROSS NORTHERN MEXICO AND S ARIZONA. UPPER LOW SHOULD
REACH EL PASO AND BIG BEND AREA BY 12Z SAT WITH HEIGHT FALLS OVER
TX AND LARGE SCALE ASCENT SPREADING INTO THE AREA.
THIS SHOULD SUPPORT THUNDERSTORM ACTIVITY ALONG THE FRONTAL
BOUNDARY TONIGHT WHICH MAY STALL JUST NORTH OF COLLEGE STATION.
SPC HIGHLIGHTS SMALL SEVERE WEATHER PROBS FOR THIS SCENARIO. AS
THE UPPER LOW MOVES EAST...EXPECT ANOTHER LINE OF STORMS TO FORM
ALONG APPROACHING PACIFIC FRONT WHICH SHOULD PUSH INTO THE ARE
DURING THE MORNING. THE 12Z TX TECH WRF AND 4KM WRF-ARW SHOW THIS
LINE DEVELOPING IN THE PRE-DAWN HOURS AND MOVING INTO THE AREA.
BASICALLY LEFT 60/70 POPS FOR OVERNIGHT TIME FRAME TO ACCOUNT FOR
THIS POSSIBILITY BUT FEEL MOST THUNDERSTORM ACTIVITY WILL BE
DURING THE DAY SATURDAY.
SATURDAY WILL BE MORE SPRING LIKE WITH REGARDS TO THUNDERSTORM
ACTIVITY THAN THE FIRST DAY OF WINTER. MODELS ARE ALL ON THE SAME
PAGE WITH HOW THE UPPER LOW MOVES TOWARDS C/NE OK BY 00Z SUN. MAIN
CONCERN WILL BE WHETHER STRONG MID LEVEL CAP WILL ERODE. 850MB
TEMPS LOOK TO WARM NEAR 16-20C ON THE GFS BY 18Z SAT. THE NAM
ERODES THE CAP QUITE A BIT DURING THIS TIME. THE PROBLEM IS THAT
NONE OF THE MODELS REALLY BRING GOOD PVA OVER THE AREA AND KEEP IT
NORTH OF THE AREA. OMEGA FIELDS SUPPORT BREAKING THE CAP BUT HAVE
SEEN SEVERAL TIMES BEFORE WHERE THE CAP HOLDS PRETTY STRONG. MAIN
QUESTION WILL BE WHEN EXACTLY THE CAP WILL BREAK. IF THE NAM HOLDS
TRUE THEN QUITE POSSIBLE TO GET DISCRETE SUPERCELLS AHEAD OF THE
DEVELOPING QLCS. HAVE NO QUESTION ABOUT OTHER SEVERE PARAMETERS AS
DEEP LAYER SHEAR AND LOW LEVEL SHEAR WILL BE OFF THE CHARTS GIVEN
STRONG LLJ AND UPPER LEVEL JET. UPPER LEVEL JET STREAK DYNAMICS
WITH RIGHT ENTRANCE REGION MOVING OVER THE AREA MAY JUST BE ENOUGH
TO ERODE THE CAP. ALL POINTS TO BASICALLY 15-21Z BEING THE FAVORED
TIME FOR SEVERE STORMS MORE LIKELY 15-18Z. OTHER LIMITING FACTOR
WILL BE INSTABILITY AS COOLING ALOFT MAY NOT BE QUITE ENOUGH TO
PUSH CAPE TO ABOVE 1500 J/KG. THINK 1000 J/KG MORE LIKELY AND THIS
STILL COULD BE ENOUGH TO SUPPORT ROBUST UPDRAFTS FOR ROTATION.
THINK SPC DAY 2 OUTLOOK IS GOOD BUT REALLY DO NOT WANT TO UNDER-
ESTIMATE THE CAP AND UPPER LEVEL DYNAMICS BEING JUST ENOUGH OUT OF
PHASE THAT A LINE OF STRONG STORMS RESULTS. STILL QUITE A BIT OF
UNCERTIANTY IN THE FORECAST BUT ENOUGH CONFIDENCE THAT THE SEVERE
POTENTIAL SHOULD BE HIGHLIGHTED.
TRUE COLD FRONT WILL PUSH THROUGH DURING THE DAY SUNDAY SO TEMPS
MAY BE A TOUCH WARMER THAN EXPECTED. HOWEVER MON/TUE AND EVEN
CHRISTMAS DAY WILL CERTAINLY FEEL LIKE WINTER AROUND SE TX.
GFS/ECMWF STILL TRYING TO SORT OUT RETURN FLOW CHRISTMAS DAY INTO
THURSDAY. WILL KEEP SOME 20 POPS DURING THAT TIME BUT REALLY DO
NOT HAVE A GOOD FEEL FOR PRECIP. LIKELY DEPENDS ON WHERE STRONGEST
ISENTROPIC LIFT SETS UP AND MODELS DIFFER BY SEVERAL HUNDERED
MILES ON WHERE THAT IS. ALSO NOTICED THAT ECMWF IS STRONGER WITH
COLD FRONT LATE NEXT THAN THE GFS WHICH HAS SEEMED TO BACK OFF.
OVERALL KEPT TREND OF ECMWF KEEPING TEMPS COLDER.
39
MARINE...
PATCHY FOG REMAINS PROBLEMATIC IN AND AROUND GALVESTON BAY WITH
VISIBILITIES FALLING TO BELOW ONE MILE AT TIMES. WITH CONDITIONS
EXPECTED TO DETERIORATE THROUGH THE EVENING HAVE ISSUED A MARINE
DENSE FOG ADVISORY FOR GALVESTON BAY AND THE ADJACENT NEARSHORE
WATERS THROUGH EARLY SATURDAY. SMALL CRAFT ADVISORY WILL REMAIN IN
PLACE FOR THE OFFSHORE WATERS THROUGH THE OVERNIGHT HOURS WITH
CAUTION FLAGS RAISED ACROSS THE NEARSHORE WATERS AND BAYS AS WINDS
INCREASE THIS EVENING.
38
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 69 72 45 62 31 / 50 80 10 10 0
HOUSTON (IAH) 70 77 49 69 35 / 40 70 30 10 0
GALVESTON (GLS) 65 71 55 68 42 / 20 60 30 10 0
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT SHOULD EXERCISE CAUTION THROUGH SATURDAY AFTERNOON
FOR THE FOLLOWING ZONES: GALVESTON BAY...MATAGORDA BAY...
WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL OUT 20
NM...WATERS FROM HIGH ISLAND TO FREEPORT OUT 20 NM.
DENSE FOG ADVISORY UNTIL 5 AM CST SATURDAY FOR THE FOLLOWING
ZONES: GALVESTON BAY...WATERS FROM HIGH ISLAND TO FREEPORT
OUT 20 NM.
SMALL CRAFT ADVISORY UNTIL 3 PM CST SATURDAY FOR THE FOLLOWING
ZONES: WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL
20 NM TO 60 NM...WATERS FROM HIGH ISLAND TO FREEPORT 20 TO
60 NM.
&&
$$
DISCUSSION...99
AVIATION/MARINE...99
AREA FORECAST DISCUSSION
NWS SPOKANE WA
445 AM PST Sat Dec 21 2013
.SYNOPSIS...
A storm system will continue to shift out the Inland Northwest
today and tonight...however moist northwest flow will persist.
This will keep the threat of light snow or freezing drizzle over
the region through the weekend. The best chances for precipitation
will occur near the Cascades and over southeast Washington and the
central Idaho Panhandle. Another storm will move into the area on
Monday, but with milder valley temperatures and less
precipitation. Drier weather is expected toward the middle to
latter part of next week, including Christmas Day.
&&
.DISCUSSION...
Today and Tonight...Yesterdays strong shortwave trough and
associated warm front has generally shifted south and east of the
region while the strong offshore ridge remains in place. This will
keep northwest flow over the area through the day. Satellite
imagery not depicting any shortwave disturbances upstream from us
at the moment...however low level moisture remains plentiful per
the latest fog product. Most of this moisture was present as an
extensive blanket of stratus covering much of the forecast area.
There was also a mid-level cloud deck covering the southern Idaho
Panhandle and SE Washington associated with weak-moderate
isentropic ascent. Radar continued to show very light returns in
these areas while nearby observations were detecting occasional
light precipitation in the form of light snow...and perhaps some
freezing drizzle. The HRRR was handling things quite well...and if
it performance remains consistent...this precipitation will wane
through the morning as it dives south of the forecast area.
Consequently we will continue to chip away at the winter
highlights. We will remove the Palouse for now...with the others
soon to follow. The precipitation should ease out of the Camas
Prairie last...and this highlight may need to be extended a couple
hours.
For tonight...the moist northwest flow continue and a weak
shortwave is expected to drop over the northern Cascades this
evening and into the Idaho Panhandle later tonight. The isentropic
ascent will strengthen ahead of the feature and should produce
another round of precipitation. This time...the amount of
atmospheric moisture will pale compared to yesterdays event while
the dendritic layer saturation and lifting looks unimpressive.
Even so...the Cascades will see good chances of precipitation
overnight...with an increasing trend for SE Washington and the
central Panhandle overnight. Most of the precipitation will fall
as light snow...however without a fully saturated dendritic
layer...some drizzle or freezing drizzle could also occur. fx
Sunday and Sunday Night: Moisture continues to move over the top
of the ridge to our west for Sunday before another system gets
set to move in Sunday Night into Monday. From current models most
of the moisture looks to get hung up in the Cascades leaving much
of the Basin essentially dry. It is not until the higher terrain
further downstream in the flow pattern that the chance for
precipitation once again returns. Given the NW flow pattern this
would allow for the Blues and Central Panhandle Mtns to see the
best chance for precip. As we move into Sunday Night the pattern
becomes more zonal as the next approaching system flattens the
ridge putting the Cascades and Panhandle Mtns as the most
influential terrain for added topographic forcing and therefore the
best chance for precipitation. Isentropic forcing looks weak to
moderate so the additional forcing will be necessary.
Snow levels will be on the rise throughout the period and can be
attributed to warmer air pushing into the region from the SSW. By
the time the best moisture arrives Sunday Night into Monday, snow
levels will be above most valley locations leading to a valley rain
mountain snow event. The one exception would be the far northern
valleys which could hold onto cold air long enough to see some snow
from the system. Temperatures look to be above normal for most as
the warm southerly air pushes into the area. /Fliehman
Monday through Friday: Now that we have some snow on the ground,
can we keep it around for a White Christmas? Monday`s weather is
going to make it tough. A short wave currently south of the
Aleutians is forecast to move through the eastern Pacific ridge
and into the Pac NW by Monday. All computer models agree that this
will set up a strong southwesterly low-level flow, and will push
the cold air out of the Inland NW. This will raise snow levels
above the valley floors, except for near the Canadian border.
Thus, this system will bring valley rain instead of snow. Not a
lot mind you. But the real snow-eater is the warm wind with dew
points above freezing. Winds will increase on Monday afternoon and
continue through the evening as the cold front passes through.
After this, drier air will move into the region and snow levels
will once again drop to the valley floors. But the high pressure
ridge re-develops, closing the door to any more Pacific storms.
Typically such a ridge would lead to the development of fog and
low clouds. Models agree, but they would suggest that there will
be enough flow the push the low clouds around instead of filling
in the entire Basin.
The only other weather feature of note will be some mid-level
moisture spilling over the ridge in the 2nd half of the week.
There`s no lifting mechanism, so this should just be confined to a
few snow showers over the northern mountains. RJ
&&
.AVIATION...
12Z TAFS: The threat of widespread precipitation has ended over the
area for the day...however widespread low clouds remain entrenched
over all sites except for MWH. The cloud bases will likely range
from 004 to 014 through most of the forecast period so look for
MVFR/IFR conditions mainly attributed to cigs. The worst conditions
will likely impact PUW as light west winds continue to reinforce the
low cigs and fog. All sites should see some subtle improvements
during the afternoon...but with fairly strong inversions in place
and light winds through the mixed layer this is far from certain.
Another disturbance moves into the region after 00z...which should
expand the low cloud blanket as well as deliver a small chance of
-shsn or -fzdz mainly for PUW and LWS. fx
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 29 22 33 28 38 26 / 0 20 20 50 70 30
Coeur d`Alene 30 24 35 29 39 29 / 0 20 30 50 80 60
Pullman 32 27 37 31 41 27 / 10 40 30 30 70 50
Lewiston 34 30 40 32 41 29 / 20 40 30 20 30 50
Colville 28 21 31 26 36 25 / 0 10 20 50 70 20
Sandpoint 29 22 32 27 37 27 / 0 30 30 50 80 70
Kellogg 30 26 34 31 38 31 / 20 50 40 50 90 70
Moses Lake 31 19 34 24 42 21 / 0 0 20 10 20 0
Wenatchee 33 24 35 27 41 25 / 10 0 20 20 10 10
Omak 26 19 31 23 35 21 / 0 10 20 20 20 10
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...Winter Storm Warning until 5 AM PST early this morning for
Central Panhandle Mountains-Lewis and Southern Nez Perce
Counties.
Winter Weather Advisory until 5 AM PST early this morning for
Lewiston Area.
WA...Winter Storm Warning until 5 AM PST early this morning for
Northeast Blue Mountains.
Winter Weather Advisory until 5 AM PST early this morning for
Lower Garfield and Asotin Counties.
&&
$$
AREA FORECAST DISCUSSION
NWS SPOKANE WA
257 AM PST Sat Dec 21 2013
.SYNOPSIS...
A storm system will continue to shift out the Inland Northwest
today and tonight...however moist northwest flow will persist.
This will keep the threat of light snow or freezing drizzle over
the region through the weekend. The best chances for precipitation
will occur near the Cascades and over southeast Washington and the
central Idaho Panhandle. Another storm will move into the area on
Monday, but with milder valley temperatures and less
precipitation. Drier weather is expected toward the middle to
latter part of next week, including Christmas Day.
&&
.DISCUSSION...
Today and Tonight...Yesterdays strong shortwave trough and
associated warm front has generally shifted south and east of the
region while the strong offshore ridge remains in place. This will
keep northwest flow over the area through the day. Satellite
imagery not depicting any shortwave disturbances upstream from us
at the moment...however low level moisture remains plentiful per
the latest fog product. Most of this moisture was present as an
extensive blanket of stratus covering much of the forecast area.
There was also a mid-level cloud deck covering the southern Idaho
Panhandle and SE Washington associated with weak-moderate
isentropic ascent. Radar continued to show very light returns in
these areas while nearby observations were detecting occasional
light precipitation in the form of light snow...and perhaps some
freezing drizzle. The HRRR was handling things quite well...and if
it performance remains consistent...this precipitation will wane
through the morning as it dives south of the forecast area.
Consequently we will continue to chip away at the winter
highlights. We will remove the Palouse for now...with the others
soon to follow. The precipitation should ease out of the Camas
Prairie last...and this highlight may need to be extended a couple
hours.
For tonight...the moist northwest flow continue and a weak
shortwave is expected to drop over the northern Cascades this
evening and into the Idaho Panhandle later tonight. The isentropic
ascent will strengthen ahead of the feature and should produce
another round of precipitation. This time...the amount of
atmospheric moisture will pale compared to yesterdays event while
the dendritic layer saturation and lifting looks unimpressive.
Even so...the Cascades will see good chances of precipitation
overnight...with an increasing trend for SE Washington and the
central Panhandle overnight. Most of the precipitation will fall
as light snow...however without a fully saturated dendritic
layer...some drizzle or freezing drizzle could also occur. fx
Sunday and Sunday Night: Moisture continues to move over the top
of the ridge to our west for Sunday before another system gets
set to move in Sunday Night into Monday. From current models most
of the moisture looks to get hung up in the Cascades leaving much
of the Basin essentially dry. It is not until the higher terrain
further downstream in the flow pattern that the chance for
precipitation once again returns. Given the NW flow pattern this
would allow for the Blues and Central Panhandle Mtns to see the
best chance for precip. As we move into Sunday Night the pattern
becomes more zonal as the next approaching system flattens the
ridge putting the Cascades and Panhandle Mtns as the most
influential terrain for added topographic forcing and therefore
the best chance for precipitation. Isentropic forcing looks weak to moderate
so the additional forcing will be necessary.
Snow levels will be on the rise throughout the period and can be
attributed to warmer air pushing into the region from the SSW. By
the time the best moisture arrives Sunday Night into Monday, snow levels
will be above most valley locations leading to a valley rain
mountain snow event. The one exception would be the far northern
valleys which could hold onto cold air long enough to see some
snow from the system. Temperatures look to be above normal for
most as the warm southerly air pushes into the area. /Fliehman
Monday through Friday: Now that we have some snow on the ground,
can we keep it around for a White Christmas? Monday`s weather is
going to make it tough. A short wave currently south of the
Aleutians is forecast to move through the eastern Pacific ridge
and into the Pac NW by Monday. All computer models agree that this
will set up a strong southwesterly low-level flow, and will push
the cold air out of the Inland NW. This will raise snow levels
above the valley floors, except for near the Canadian border.
Thus, this system will bring valley rain instead of snow. Not a
lot mind you. But the real snow-eater is the warm wind with dew
points above freezing. Winds will increase on Monday afternoon and
continue through the evening as the cold front passes through.
After this, drier air will move into the region and snow levels
will once again drop to the valley floors. But the high pressure
ridge re-develops, closing the door to any more Pacific storms.
Typically such a ridge would lead to the development of fog and
low clouds. Models agree, but they would suggest that there will
be enough flow the push the low clouds around instead of filling
in the entire Basin.
The only other weather feature of note will be some mid-level
moisture spilling over the ridge in the 2nd half of the week.
There`s no lifting mechanism, so this should just be confined to a
few snow showers over the northern mountains. RJ
&&
.AVIATION...
06Z TAFS: A storm system will continue to move through southeast
WA and central Idaho tonight into Saturday morning. This passing
feature and northwest flow will keep some light snow and/or
freezing rain in the region of the KLWS/KPUW TAFs through 10-12Z.
Some patchy freezing drizzle is also possible about the KGEG to
KCOE corridor. Otherwise look for some low clouds, with IFR/LIFR
conditions, including some mist/fog with visibilities occasionally
under 2 miles. Some of these are expected to expand toward KEAT
through the night too. Conditions are then expected to gradually
improve through the day Saturday, with some brief VFR/MVFR
conditions in the mid-afternoon, before conditions degrade again
after 00-03Z. Additional light snow will be possible Saturday
night, though the better chances will hold off until after 06Z
Sunday. /J. Cote`
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 29 22 33 28 38 26 / 0 20 20 50 70 30
Coeur d`Alene 30 24 35 29 39 29 / 0 20 30 50 80 60
Pullman 32 27 37 31 41 27 / 10 40 30 30 70 50
Lewiston 34 30 40 32 41 29 / 20 40 30 20 30 50
Colville 28 21 31 26 36 25 / 0 10 20 50 70 20
Sandpoint 29 22 32 27 37 27 / 0 30 30 50 80 70
Kellogg 30 26 34 31 38 31 / 20 50 40 50 90 70
Moses Lake 31 19 34 24 42 21 / 0 0 20 10 20 0
Wenatchee 33 24 35 27 41 25 / 10 0 20 20 10 10
Omak 26 19 31 23 35 21 / 0 10 20 20 20 10
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...Winter Storm Warning until 5 AM PST early this morning for
Central Panhandle Mountains-Lewis and Southern Nez Perce
Counties.
Winter Weather Advisory until 5 AM PST early this morning for
Lewiston Area.
WA...Winter Storm Warning until 5 AM PST early this morning for
Northeast Blue Mountains.
Winter Weather Advisory until 5 AM PST early this morning for
Lower Garfield and Asotin Counties.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1118 AM CST SAT DEC 21 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 343 AM CST SAT DEC 21 2013
CONCENTRATING ON REFINING THE WINTER STORM DETAILS AND IMPACTS IN
THE FORECAST SUITE. IN GENERAL...THERE HAVE BEEN MINOR CHANGES TO
THE FORECAST FOR THIS STORM...AND IT STILL LOOKS ON TRACK.
THIS SYSTEM IS WHY MANY METEOROLOGISTS WENT INTO WEATHER. THE
POWER RIGHT NOW FROM THIS SYSTEM IN THE SOUTHERN U.S. IS
REMARKABLE. GOES WATER VAPOR CLEARLY SHOWING THE STRONG TROUGH
OVER SRN NEW MEXICO WITH STRONG QVECTOR CONVERGENCE AND FORCING
OVER WESTERN TEXAS /GREAT TRANSVERSE WAVES ON IR IMAGERY/. SURFACE
PRESSURES ARE FALLING IN ARKANSAS ABOUT 1MB/HR...AND THE LOW-LEVEL
JET IS INCREASING INTO A FRONTAL ZONE DEFINED BY 34F TO 72F ACROSS
NRN AR...AND CONVECTION WITH C-G LIGHTNING. DEWPOINTS IN THE WARM
SECTOR ARE IN THE LOWER 70S ILLUSTRATING THE AMOUNT OF MOISTURE
DRAWING INTO THIS SYSTEM.
THIS STORM HAS ALL THE DYNAMICS FOR A MAJOR PRECIPITATION
PRODUCER...STRONG AND COMPACT QVECTOR CONVERGENCE/DIVERGENCE
DIPOLE...UPPER LEVEL JET ENTRANCE REGION DIVERGENCE ALOFT /JET MAX
OVER SRN CANADA OF 180KTS FORECAST/...STRONG FRONTOGENETIC FORCING
AT 600-700MB /GREAT FOR SNOW PRODUCTION/. SO...THE QUESTION IS
WHERE WILL THE SNOW BAND LAY DOWN...WITHIN A COUNTY...AND TRYING
TO UNDERSTAND WHY THE MODELS ARE STILL DIFFERENT.
SINCE 20.12Z...THE NAM HAS REALLY CHANGED ITS TUNE TO A WET AND WEST
AND MORE IN-LINE SOLUTION WITH THE GFS/EC/CANADIAN...AND HAS BEEN
CONSISTENT WITH ITS OUTCOMES IN THE LAST 3 RUNS. THE HIGHEST
PRECIPITATION BAND IS CONSISTENT WITH THE 20.12 ECMWF AND LATEST
CANADIAN/GFS RUNS...ROUGHLY FROM KDBQ-KDLL AND SOUTHEAST. THE
21.12Z ECMWF HAS SHIFTED A BIT EAST NOW. OVERALL...THE ECMWF SEEMS
TO HAVE THE BEST 500MB DEPICTION INDICATING A STRONG NEARLY CLOSED
LOW SHIFTING NORTHEAST...WHILE THE 21.00Z GFS VORTICITY IS
DISORGANIZED AND CHANNELED...AND THE GFS SURFACE LOW FURTHEST
EAST. WPC MODEL GUIDANCE DISCUSSION PREFERRED AN ECMWF SOLUTION OR
NON-NCEP ENSEMBLE. BOTTOM LINE IS THEY ARE ALL VERY REASONABLE ON
QPF/SNOW AMOUNTS EXCEPT POSSIBLY THE NAM THAT SEEMS TO SPREAD TOO
MUCH PRECIPITATION NORTHWEST...SUGGESTING IMPACTS FURTHER WEST
INTO MN/IA...A WIDE ADVISORY SNOW AREA. WHILE THIS SOLUTION CANNOT
BE DISCOUNTED...THE NORTHERN STREAM INFLUENCE/DEFORMATION SHOULD
LIMITED THE WESTWARD EXTENT....AND THE UPPER JET DIVERGENCE SEEMS
TO SUPPORT A MORE WI/IL SOLUTION FOR THE BEST LIFT /EAST/.
SNOW FORECAST REMAINS CONSISTENT...BUT HAVE MADE A SLIGHT TWEAK
WEST...MAYBE ONE-HALF A COUNTY. THE WARNING IS WELL PLACED...BUT
HAVE DECIDED TO INCLUDE JUNEAU AND ADAMS COUNTY IN CENTRAL WI.
ALSO HAVE ADDED FAYETTE COUNTY TO THE WARNING AFTER COLLABORATION
WITH DMX. HAVE CHANGED THE REMAINING WATCH COUNTIES TO AN ADVISORY
AND BASED ON THE 3 INCH SNOW TOTAL LINE...BUILT A FEW OTHER
COUNTIES INTO THE ADVISORY WESTWARD.
TIMING...
LATEST RUNS OF THE RAP INDICATE THE POSSIBILITY OF PRECIPITATION
TO THE IL/WI BORDER BY 6 PM TONIGHT. THIS IS A BIT FASTER TREND
THAN THE OTHER MODELS WHICH BEGIN SNOW AROUND 8-9PM IN THE SOUTH.
EVEN THOUGH CONSENSUS IS FOR ONSET IN THE SOUTH AT 8-9 PM HAVE
LEFT THAT START TIME 6 PM FOR NOW. THAT CAN BE ADJUSTED IF NEEDED.
HOWEVER...HAVE ADJUSTED START TIME IN CENTRAL WI TO 03Z/9PM FOR
THE WARNING...BASICALLY THE I-90 CORRIDOR. THE HEAVIEST SNOW WILL
FALL FROM ABOUT 3 AM TO 9 AM.
IMPACTS...
BECAUSE THIS STORM HAS SHORTER DURATION...WARNING SNOW
AMOUNTS WILL NOT BE UNUSUAL IN THE FORECAST AREA WITH 6 TO 8
INCHES EXPECTED AND 2 TO 5 IN THE ADVISORY. WINDS WILL BE
STRONGEST IN SERN MN INTO NERN IA...15 TO 25 MPH. THIS LEADS TO
THE UPGRADE TO WARNING IN FAYETTE AS A BIT MORE BLOWING IS
EXPECTED THERE WITH 4-5 INCHES OF SNOW.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 343 AM CST SAT DEC 21 2013
SNOW SLOWLY DIMINISHES TO FLURRIES OR VERY LIGHT ACCUMULATING SNOW
SUNDAY AFTERNOON. HOWEVER...THE NORTHERN STREAM DAKOTAS SHORTWAVE
TROUGH WILL BE MOVING IN WITH THE SURGE OF ARCTIC AIR SUNDAY
NIGHT. THIS FORCING AND COLD ADVECTION WILL PROVIDE SOME
INSTABILITY AND LIFT FOR AN EXTENSION OF LIGHTLY ACCUMULATING
SNOW. SUNDAY NIGHT AND MONDAY MORNING COULD BRING ANOTHER 1-2
INCHES OF FLUFFY SNOW...WITH THE 2 INCH AMOUNTS NEAR AND NORTHEAST
OF I-94. THIS IS A LARGER CHANGE IN THE FORECAST.
AN ACTIVE PATTERN CONTINUES THROUGH THE WEEK WITH WARM ADVECTION
SNOWFALL POSSIBLE CHRISTMAS EVE AND ANOTHER VIGOROUS TROUGH
POSSIBLY THURSDAY WITH ANOTHER COLD AIR SURGE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1118 AM CST SAT DEC 21 2013
THERE LOOKS TO BE A GROWING MODEL CONSENSUS BETWEEN THE 21.12Z NAM
AND GFS...21.06Z HI-RES ARW AND NMM AND THE 21.09Z SREF MEMBERS
THAT THE WORST CONDITIONS FROM THE INCOMING WINTER STORM WILL STAY
SOUTHEAST OF BOTH TAF SITES. STILL EXPECT TO SEE SNOW OVERNIGHT
INTO SUNDAY MORNING FOR BOTH TAF SITES...BUT CONDITIONS MAY NOT BE
A BAD AS PREVIOUSLY EXPECTED. CURRENT CEILINGS ARE EXPECTED TO
SLOWLY GO DOWN THROUGH THE AFTERNOON WITH IFR AT BOTH SITES BY MID
TO LATE AFTERNOON. LOOK FOR THESE CONDITIONS TO THEN PREVAIL
THROUGH THE REST OF THE PERIOD. THE SNOW SHOULD MOVE IN LATE
TONIGHT AND IMPACT KLSE THE MOST. THE VISIBILITY WILL GO DOWN TO
IFR SHORTLY AFTER THE SNOW BEGINS AND IS EXPECTED TO GO DOWN TO
ABOUT A MILE OR SO DURING THE HEAVIEST PERIOD OF SNOW EARLY SUNDAY
MORNING. THE SREF WOULD SUGGEST THIS MAY TOO PESSIMISTIC AS IT HAS
ALMOST NO SIGNAL FOR VISIBILITIES UNDER A MILE AT KLSE AND ONLY A
SMALL SIGNAL FOR LESS THAN 3 MILE VISIBILITIES. THE SNOW WILL
START TO SHIFT OFF TO THE EAST LATE SUNDAY MORNING WITH SOME
IMPROVEMENT OCCURRING AT KRST. DID NOT SHOW ANY IMPROVEMENT AT
KLSE WITH THIS FORECAST AS THE TIMING OF THIS LOOKS TO BE RIGHT AT
THE END OF THE FORECAST PERIOD.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 PM CST
SUNDAY FOR WIZ053.
WINTER STORM WARNING FROM 6 PM THIS EVENING TO 6 PM CST SUNDAY
FOR WIZ054-055-061.
WINTER WEATHER ADVISORY FROM 9 PM THIS EVENING TO 6 PM CST
SUNDAY FOR WIZ034-041-042.
WINTER STORM WARNING FROM 9 PM THIS EVENING TO 6 PM CST SUNDAY
FOR WIZ043-044.
MN...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 PM CST
SUNDAY FOR MNZ096.
IA...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 PM CST
SUNDAY FOR IAZ010-011-019.
WINTER STORM WARNING FROM 6 PM THIS EVENING TO 6 PM CST SUNDAY
FOR IAZ029-030.
&&
$$
SHORT TERM...BAUMGARDT
LONG TERM...BAUMGARDT
AVIATION...04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
524 AM CST SAT DEC 21 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 343 AM CST SAT DEC 21 2013
CONCENTRATING ON REFINING THE WINTER STORM DETAILS AND IMPACTS IN
THE FORECAST SUITE. IN GENERAL...THERE HAVE BEEN MINOR CHANGES TO
THE FORECAST FOR THIS STORM...AND IT STILL LOOKS ON TRACK.
THIS SYSTEM IS WHY MANY METEOROLOGISTS WENT INTO WEATHER. THE
POWER RIGHT NOW FROM THIS SYSTEM IN THE SOUTHERN U.S. IS
REMARKABLE. GOES WATER VAPOR CLEARLY SHOWING THE STRONG TROUGH
OVER SRN NEW MEXICO WITH STRONG QVECTOR CONVERGENCE AND FORCING
OVER WESTERN TEXAS /GREAT TRANSVERSE WAVES ON IR IMAGERY/. SURFACE
PRESSURES ARE FALLING IN ARKANSAS ABOUT 1MB/HR...AND THE LOW-LEVEL
JET IS INCREASING INTO A FRONTAL ZONE DEFINED BY 34F TO 72F ACROSS
NRN AR...AND CONVECTION WITH C-G LIGHTNING. DEWPOINTS IN THE WARM
SECTOR ARE IN THE LOWER 70S ILLUSTRATING THE AMOUNT OF MOISTURE
DRAWING INTO THIS SYSTEM.
THIS STORM HAS ALL THE DYNAMICS FOR A MAJOR PRECIPITATION
PRODUCER...STRONG AND COMPACT QVECTOR CONVERGENCE/DIVERGENCE
DIPOLE...UPPER LEVEL JET ENTRANCE REGION DIVERGENCE ALOFT /JET MAX
OVER SRN CANADA OF 180KTS FORECAST/...STRONG FRONTOGENETIC FORCING
AT 600-700MB /GREAT FOR SNOW PRODUCTION/. SO...THE QUESTION IS
WHERE WILL THE SNOW BAND LAY DOWN...WITHIN A COUNTY...AND TRYING
TO UNDERSTAND WHY THE MODELS ARE STILL DIFFERENT.
SINCE 20.12Z...THE NAM HAS REALLY CHANGED ITS TUNE TO A WET AND WEST
AND MORE IN-LINE SOLUTION WITH THE GFS/EC/CANADIAN...AND HAS BEEN
CONSISTENT WITH ITS OUTCOMES IN THE LAST 3 RUNS. THE HIGHEST
PRECIPITATION BAND IS CONSISTENT WITH THE 20.12 ECMWF AND LATEST
CANADIAN/GFS RUNS...ROUGHLY FROM KDBQ-KDLL AND SOUTHEAST. THE
21.12Z ECMWF HAS SHIFTED A BIT EAST NOW. OVERALL...THE ECMWF SEEMS
TO HAVE THE BEST 500MB DEPICTION INDICATING A STRONG NEARLY CLOSED
LOW SHIFTING NORTHEAST...WHILE THE 21.00Z GFS VORTICITY IS
DISORGANIZED AND CHANNELED...AND THE GFS SURFACE LOW FURTHEST
EAST. WPC MODEL GUIDANCE DISCUSSION PREFERRED AN ECMWF SOLUTION OR
NON-NCEP ENSEMBLE. BOTTOM LINE IS THEY ARE ALL VERY REASONABLE ON
QPF/SNOW AMOUNTS EXCEPT POSSIBLY THE NAM THAT SEEMS TO SPREAD TOO
MUCH PRECIPITATION NORTHWEST...SUGGESTING IMPACTS FURTHER WEST
INTO MN/IA...A WIDE ADVISORY SNOW AREA. WHILE THIS SOLUTION CANNOT
BE DISCOUNTED...THE NORTHERN STREAM INFLUENCE/DEFORMATION SHOULD
LIMITED THE WESTWARD EXTENT....AND THE UPPER JET DIVERGENCE SEEMS
TO SUPPORT A MORE WI/IL SOLUTION FOR THE BEST LIFT /EAST/.
SNOW FORECAST REMAINS CONSISTENT...BUT HAVE MADE A SLIGHT TWEAK
WEST...MAYBE ONE-HALF A COUNTY. THE WARNING IS WELL PLACED...BUT
HAVE DECIDED TO INCLUDE JUNEAU AND ADAMS COUNTY IN CENTRAL WI.
ALSO HAVE ADDED FAYETTE COUNTY TO THE WARNING AFTER COLLABORATION
WITH DMX. HAVE CHANGED THE REMAINING WATCH COUNTIES TO AN ADVISORY
AND BASED ON THE 3 INCH SNOW TOTAL LINE...BUILT A FEW OTHER
COUNTIES INTO THE ADVISORY WESTWARD.
TIMING...
LATEST RUNS OF THE RAP INDICATE THE POSSIBILITY OF PRECIPITATION
TO THE IL/WI BORDER BY 6 PM TONIGHT. THIS IS A BIT FASTER TREND
THAN THE OTHER MODELS WHICH BEGIN SNOW AROUND 8-9PM IN THE SOUTH.
EVEN THOUGH CONSENSUS IS FOR ONSET IN THE SOUTH AT 8-9 PM HAVE
LEFT THAT START TIME 6 PM FOR NOW. THAT CAN BE ADJUSTED IF NEEDED.
HOWEVER...HAVE ADJUSTED START TIME IN CENTRAL WI TO 03Z/9PM FOR
THE WARNING...BASICALLY THE I-90 CORRIDOR. THE HEAVIEST SNOW WILL
FALL FROM ABOUT 3 AM TO 9 AM.
IMPACTS...
BECAUSE THIS STORM HAS SHORTER DURATION...WARNING SNOW
AMOUNTS WILL NOT BE UNUSUAL IN THE FORECAST AREA WITH 6 TO 8
INCHES EXPECTED AND 2 TO 5 IN THE ADVISORY. WINDS WILL BE
STRONGEST IN SERN MN INTO NERN IA...15 TO 25 MPH. THIS LEADS TO
THE UPGRADE TO WARNING IN FAYETTE AS A BIT MORE BLOWING IS
EXPECTED THERE WITH 4-5 INCHES OF SNOW.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 343 AM CST SAT DEC 21 2013
SNOW SLOWLY DIMINISHES TO FLURRIES OR VERY LIGHT ACCUMULATING SNOW
SUNDAY AFTERNOON. HOWEVER...THE NORTHERN STREAM DAKOTAS SHORTWAVE
TROUGH WILL BE MOVING IN WITH THE SURGE OF ARCTIC AIR SUNDAY
NIGHT. THIS FORCING AND COLD ADVECTION WILL PROVIDE SOME
INSTABILITY AND LIFT FOR AN EXTENSION OF LIGHTLY ACCUMULATING
SNOW. SUNDAY NIGHT AND MONDAY MORNING COULD BRING ANOTHER 1-2
INCHES OF FLUFFY SNOW...WITH THE 2 INCH AMOUNTS NEAR AND NORTHEAST
OF I-94. THIS IS A LARGER CHANGE IN THE FORECAST.
AN ACTIVE PATTERN CONTINUES THROUGH THE WEEK WITH WARM ADVECTION
SNOWFALL POSSIBLE CHRISTMAS EVE AND ANOTHER VIGOROUS TROUGH
POSSIBLY THURSDAY WITH ANOTHER COLD AIR SURGE.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 524 AM CST SAT DEC 21 2013
IFR/MVFR CLOUD COVER WILL CONTINUE THROUGH TODAY. ATTENTION THEN
TURNS TO A POTENT LOW PRESSURE SYSTEM LIFTING OUT OF THE SOUTHERN
PLAINS INTO THE GREAT LAKES REGION TONIGHT THROUGH SUNDAY. SNOW IS
EXPECTED TO SPREAD INTO NORTHEAST IA/SOUTHERN WI THIS EVENING AND
THEN INTO THE KLSE/KRST TAF SITES AFTER 07Z/09Z RESPECTIVELY. DUE
TO THE TRACK OF THE STORM SYSTEM...KLSE LOOKS TO BE IMPACTED BY
MODERATE SNOWFALL SNOW AT TIMES AFTER 10Z WITH TEMPORARY LIFR
VSBY/CIG CONDITIONS THROUGH MID-SUNDAY MORNING. LIGHTER SNOWFALL
WILL BE SEEN AT KRST AS A RESULT OF BEING FARTHER NORTHWEST OF
THE TRACK OF THE LOW...BUT REMAINING IN IFR CONDITIONS.
RIGHT NOW...IT APPEARS AROUND 3 INCHES OF SNOWFALL IS LIKELY
TONIGHT THROUGH SUNDAY AT KLSE WITH 1 TO 1.5 INCHES LIKELY AT
KRST.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 PM CST
SUNDAY FOR WIZ053.
WINTER STORM WARNING FROM 6 PM THIS EVENING TO 6 PM CST SUNDAY
FOR WIZ054-055-061.
WINTER WEATHER ADVISORY FROM 9 PM THIS EVENING TO 6 PM CST
SUNDAY FOR WIZ034-041-042.
WINTER STORM WARNING FROM 9 PM THIS EVENING TO 6 PM CST SUNDAY
FOR WIZ043-044.
MN...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 PM CST
SUNDAY FOR MNZ096.
IA...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 PM CST
SUNDAY FOR IAZ010-011-019.
WINTER STORM WARNING FROM 6 PM THIS EVENING TO 6 PM CST SUNDAY
FOR IAZ029-030.
&&
$$
SHORT TERM...BAUMGARDT
LONG TERM...BAUMGARDT
AVIATION...DAS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
343 AM CST SAT DEC 21 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 343 AM CST SAT DEC 21 2013
CONCENTRATING ON REFINING THE WINTER STORM DETAILS AND IMPACTS IN
THE FORECAST SUITE. IN GENERAL...THERE HAVE BEEN MINOR CHANGES TO
THE FORECAST FOR THIS STORM...AND IT STILL LOOKS ON TRACK.
THIS SYSTEM IS WHY MANY METEOROLOGISTS WENT INTO WEATHER. THE
POWER RIGHT NOW FROM THIS SYSTEM IN THE SOUTHERN U.S. IS
REMARKABLE. GOES WATER VAPOR CLEARLY SHOWING THE STRONG TROUGH
OVER SRN NEW MEXICO WITH STRONG QVECTOR CONVERGENCE AND FORCING
OVER WESTERN TEXAS /GREAT TRANSVERSE WAVES ON IR IMAGERY/. SURFACE
PRESSURES ARE FALLING IN ARKANSAS ABOUT 1MB/HR...AND THE LOW-LEVEL
JET IS INCREASING INTO A FRONTAL ZONE DEFINED BY 34F TO 72F ACROSS
NRN AR...AND CONVECTION WITH C-G LIGHTNING. DEWPOINTS IN THE WARM
SECTOR ARE IN THE LOWER 70S ILLUSTRATING THE AMOUNT OF MOISTURE
DRAWING INTO THIS SYSTEM.
THIS STORM HAS ALL THE DYNAMICS FOR A MAJOR PRECIPITATION
PRODUCER...STRONG AND COMPACT QVECTOR CONVERGENCE/DIVERGENCE
DIPOLE...UPPER LEVEL JET ENTRANCE REGION DIVERGENCE ALOFT /JET MAX
OVER SRN CANADA OF 180KTS FORECAST/...STRONG FRONTOGENETIC FORCING
AT 600-700MB /GREAT FOR SNOW PRODUCTION/. SO...THE QUESTION IS
WHERE WILL THE SNOW BAND LAY DOWN...WITHIN A COUNTY...AND TRYING
TO UNDERSTAND WHY THE MODELS ARE STILL DIFFERENT.
SINCE 20.12Z...THE NAM HAS REALLY CHANGED ITS TUNE TO A WET AND WEST
AND MORE IN-LINE SOLUTION WITH THE GFS/EC/CANADIAN...AND HAS BEEN
CONSISTENT WITH ITS OUTCOMES IN THE LAST 3 RUNS. THE HIGHEST
PRECIPITATION BAND IS CONSISTENT WITH THE 20.12 ECMWF AND LATEST
CANADIAN/GFS RUNS...ROUGHLY FROM KDBQ-KDLL AND SOUTHEAST. THE
21.12Z ECMWF HAS SHIFTED A BIT EAST NOW. OVERALL...THE ECMWF SEEMS
TO HAVE THE BEST 500MB DEPICTION INDICATING A STRONG NEARLY CLOSED
LOW SHIFTING NORTHEAST...WHILE THE 21.00Z GFS VORTICITY IS
DISORGANIZED AND CHANNELED...AND THE GFS SURFACE LOW FURTHEST
EAST. WPC MODEL GUIDANCE DISCUSSION PREFERRED AN ECMWF SOLUTION OR
NON-NCEP ENSEMBLE. BOTTOM LINE IS THEY ARE ALL VERY REASONABLE ON
QPF/SNOW AMOUNTS EXCEPT POSSIBLY THE NAM THAT SEEMS TO SPREAD TOO
MUCH PRECIPITATION NORTHWEST...SUGGESTING IMPACTS FURTHER WEST
INTO MN/IA...A WIDE ADVISORY SNOW AREA. WHILE THIS SOLUTION CANNOT
BE DISCOUNTED...THE NORTHERN STREAM INFLUENCE/DEFORMATION SHOULD
LIMITED THE WESTWARD EXTENT....AND THE UPPER JET DIVERGENCE SEEMS
TO SUPPORT A MORE WI/IL SOLUTION FOR THE BEST LIFT /EAST/.
SNOW FORECAST REMAINS CONSISTENT...BUT HAVE MADE A SLIGHT TWEAK
WEST...MAYBE ONE-HALF A COUNTY. THE WARNING IS WELL PLACED...BUT
HAVE DECIDED TO INCLUDE JUNEAU AND ADAMS COUNTY IN CENTRAL WI.
ALSO HAVE ADDED FAYETTE COUNTY TO THE WARNING AFTER COLLABORATION
WITH DMX. HAVE CHANGED THE REMAINING WATCH COUNTIES TO AN ADVISORY
AND BASED ON THE 3 INCH SNOW TOTAL LINE...BUILT A FEW OTHER
COUNTIES INTO THE ADVISORY WESTWARD.
TIMING...
LATEST RUNS OF THE RAP INDICATE THE POSSIBILITY OF PRECIPITATION
TO THE IL/WI BORDER BY 6 PM TONIGHT. THIS IS A BIT FASTER TREND
THAN THE OTHER MODELS WHICH BEGIN SNOW AROUND 8-9PM IN THE SOUTH.
EVEN THOUGH CONSENSUS IS FOR ONSET IN THE SOUTH AT 8-9 PM HAVE
LEFT THAT START TIME 6 PM FOR NOW. THAT CAN BE ADJUSTED IF NEEDED.
HOWEVER...HAVE ADJUSTED START TIME IN CENTRAL WI TO 03Z/9PM FOR
THE WARNING...BASICALLY THE I-90 CORRIDOR. THE HEAVIEST SNOW WILL
FALL FROM ABOUT 3 AM TO 9 AM.
IMPACTS...
BECAUSE THIS STORM HAS SHORTER DURATION...WARNING SNOW
AMOUNTS WILL NOT BE UNUSUAL IN THE FORECAST AREA WITH 6 TO 8
INCHES EXPECTED AND 2 TO 5 IN THE ADVISORY. WINDS WILL BE
STRONGEST IN SERN MN INTO NERN IA...15 TO 25 MPH. THIS LEADS TO
THE UPGRADE TO WARNING IN FAYETTE AS A BIT MORE BLOWING IS
EXPECTED THERE WITH 4-5 INCHES OF SNOW.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 343 AM CST SAT DEC 21 2013
SNOW SLOWLY DIMINISHES TO FLURRIES OR VERY LIGHT ACCUMULATING SNOW
SUNDAY AFTERNOON. HOWEVER...THE NORTHERN STREAM DAKOTAS SHORTWAVE
TROUGH WILL BE MOVING IN WITH THE SURGE OF ARCTIC AIR SUNDAY
NIGHT. THIS FORCING AND COLD ADVECTION WILL PROVIDE SOME
INSTABILITY AND LIFT FOR AN EXTENSION OF LIGHTLY ACCUMULATING
SNOW. SUNDAY NIGHT AND MONDAY MORNING COULD BRING ANOTHER 1-2
INCHES OF FLUFFY SNOW...WITH THE 2 INCH AMOUNTS NEAR AND NORTHEAST
OF I-94. THIS IS A LARGER CHANGE IN THE FORECAST.
AN ACTIVE PATTERN CONTINUES THROUGH THE WEEK WITH WARM ADVECTION
SNOWFALL POSSIBLE CHRISTMAS EVE AND ANOTHER VIGOROUS TROUGH
POSSIBLY THURSDAY WITH ANOTHER COLD AIR SURGE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1140 PM CST FRI DEC 20 2013
MVFR TO IFR CEILINGS WILL LINGER THROUGH TOMORROW AS ONE LOW
PRESSURE SYSTEM TRACKS TO THE EAST IN THE GREAT LAKES WHILE A
SECOND...MORE POTENT LOW IS DEVELOPING IN THE SOUTHERN PLAINS.
THIS SECOND LOW WILL BRING SNOW INTO THE REGION OVERNIGHT ON
SATURDAY...BUT NOT UNTIL AFTER THE END OF THIS TAF PERIOD. WHILE
CONDITIONS MAY BRIEFLY IMPROVE ON SATURDAY...THEY SHOULD DROP
AGAIN SATURDAY NIGHT AS LOW LEVEL MOISTURE INCREASES ACROSS THE
REGION. WINDS WILL REMAIN LIGHT THROUGH MUCH OF THE DAY BEFORE
GOING NORTHEAST AND INCREASING TO AROUND 10-15KTS SATURDAY NIGHT.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 PM CST
SUNDAY FOR WIZ053.
WINTER STORM WARNING FROM 6 PM THIS EVENING TO 6 PM CST SUNDAY
FOR WIZ054-055-061.
WINTER WEATHER ADVISORY FROM 9 PM THIS EVENING TO 6 PM CST
SUNDAY FOR WIZ034-041-042.
WINTER STORM WARNING FROM 9 PM THIS EVENING TO 6 PM CST SUNDAY
FOR WIZ043-044.
MN...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 PM CST
SUNDAY FOR MNZ096.
IA...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 PM CST
SUNDAY FOR IAZ010-011-019.
WINTER STORM WARNING FROM 6 PM THIS EVENING TO 6 PM CST SUNDAY
FOR IAZ029-030.
&&
$$
SHORT TERM...BAUMGARDT
LONG TERM...BAUMGARDT
AVIATION...HALBACH
AREA FORECAST DISCUSSION
NWS ALBANY NY
403 AM EST MON DEC 23 2013
.SYNOPSIS...
LOW PRESSURE WILL MOVE UP THE EASTERN SEABOARD TODAY...BRINGING
ONE MORE ROUND OF RAIN TO SOUTHERN NEW ENGLAND AND IN NEW YORK
FROM THE CAPITAL DISTRICT SOUTH. IN ITS WAKE COLD AIR WILL FILTER
INTO OUR REGION THIS AFTERNOON AS WINDS INCREASE. EVEN COLDER AIR
WILL MOVE INTO THE REGION AS HIGH PRESSURE MOVES FROM ONTARIO
TONIGHT TO NEW YORK AND NEW ENGLAND CHRISTMAS DAY. THE REST OF THE
WEEK WILL FEATURE A SERIES OF WEAK FAST MOVING WEATHER
SYSTEMS...WITH VARIABLE CLOUDINESS...SCATTERED SNOW SHOWERS AND
SEASONABLE TEMPERATURES.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 300 AM EST...NEARLY STATIONARY FRONTAL BOUNDARY CONTINUES TO
BE SITUATED FROM WEST TO EAST ACROSS THE CENTRAL PORTION OF THE CWA
EARLY THIS MORNING. TO THE NORTH OF THIS BOUNDARY...IMPRESSIVE CAD
CONTINUES ACROSS THE LAKE GEORGE/SARATOGA REGION...WITH TEMPS CLOSE
TO FREEZING. MEANWHILE...OTHER AREAS NORTH OF THE BOUNDARY GENERALLY
ARE IN THE MID 30S TO MID 40S. SOUTH OF THE BOUNDARY...TEMPS ARE IN
THE 40S ACROSS THE LOWER ELEVATIONS...AND 50S OVER THE HIGH TERRAIN.
THESE WARM TEMPS OVER THE HIGHER ELEVATIONS WILL START TO LOWER OVER
THE NEXT FEW HOURS...AS FORECAST MODEL SOUNDINGS SHOWS THE
IMPRESSIVE WARM NOSE AT AROUND 900-950 HPA IS FINALLY BEING PUSHED
AWAY FROM THE REGION THANKS A STRONG SW FLOW ALOFT.
STILL...THE AIR MOVING IN THIS MORNING ISN/T OVERLY CHILLY JUST
YET...AS OUR REGION IS BEING INFLUENCED BY A STRONG MEDIRONDAL FLOW
AHEAD OF A DEEP UPPER LEVEL TROUGH SITUATED OVER THE CENTRAL PORTION
OF THE US. IN ADDITION...THIS FLOW IS CONTINUING TO TRANSPORT PLENTY
OF MID/HIGH LEVEL MOISTURE STRAIGHT OUT OF PACIFIC AND GULF OF
MEXICO TOWARDS OUR AREA. PWATS WILL CONTINUE TO BE ABOVE NORMAL
TODAY...WITH FORECASTED VALUES EXPECTED TO BE AROUND AN INCH...WHICH
IS ABOUT 2 STD ABOVE NORMAL.
DURING THE DAY TODAY...AN AREA OF LOW PRESSURE /DEVELOPING ACROSS
THE SOUTHEAST US EARLY THIS MORNING/ WILL RIDE NORTHWARD ALONG THE
EASTERN SEABOARD. REGIONAL RADAR ALREADY SHOWS A SOLID AREA OF
STEADY RAIN AHEAD OF THIS DEVELOPING SYSTEM OVER THE MID ATLANTIC
STATES...AND THIS WILL BE RIDING FROM SOUTHWEST TO NORTHEAST ACROSS
THE REGION TODAY. THE 00Z NAM/GFS/ECMWF AND 05Z 3KM HRRR ALL SHOW
THIS PRECIP MOVING FROM SOUTHWEST TO NORTHEAST ACROSS OUR REGION
BETWEEN JUST SHORTLY BEFORE SUNRISE AND THROUGH THE MORNING HOURS.
THE BEST CHC FOR PRECIP WILL BE ACROSS THE SOUTHERN AND EASTERN
PORTION OF THE CWA...WHERE UP TO AROUND A HALF INCH OF RAIN WILL
FALL FOR LITCHFIELD COUNTY.
PRECIP WILL FALL MAINLY IN THE FORM OF LIQUID RAIN. WITH CONTINUED
MARGINAL TEMPS IN THE LAKE GEORGE/SARATOGA REGION...IT/S POSSIBLE
THAT THERE MAY INITIALLY BE SOME SPOTTY FREEZING RAIN ONCE THE
PRECIP MOVES IN...BUT TEMPS SHOULD WARM UP ENOUGH TO AVOID A
PROLONGED PERIOD OF FREEZING RAIN THERE. OTHERWISE...THE ONLY OTHER
PLACE THERE COULD BE SOME WINTRY PRECIP IS THE FAR NORTHWESTERN
ADIRONDACKS...WHERE COLDER AIR SNEAKING IN ALOFT MAY ALLOW FOR THE
PRECIP TO CHANGEOVER TO SLEET/SNOW. LITTLE QPF IS EXPECTED THAT FAR
NW...SO ANY ACCUMULATION WILL BE LIMITED TO JUST A COATING.
MOST AREAS LOOK TO SEE MAX TEMPS IN THE MORNING HOURS...WITH TEMPS
RANGING FROM THE MID 30S IN THE ADIRONDACKS TO THE MID 50S IN THE
MID HUDSON VALLEY AND NW CT. MOST TEMPS WILL HOLD STEADY THIS
MORNING...ALTHOUGH THE CAD IN THE LAKE GEORGE/SARATOGA AREA SHOULD
GIVE WAY ENOUGH FOR TEMPS THERE TO RISE TOWARDS THE UPPER 30S TO LOW
40S BY THE LATE MORNING HOURS.
BY THE AFTN...STEADY PRECIP WILL BE MOVING ACROSS NEW ENGLAND...AND
THERE WILL BE JUST A FEW LINGERING SHOWERS...MAINLY ACROSS THE
HIGHER ELEVATIONS. WITH COLDER AIR SURGING IN ON WESTERLY
WINDS...TEMPS WILL TUMBLE ACROSS MOST AREAS DURING THE AFTN
HOURS...FALLING FROM THE 40S INTO THE 30S ACROSS MUCH OF THE REGION.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
GENERALLY THE MODEL SUITE (GEM/GFS/NAM/ECMWF) IS IN AGREEMENT DURING THIS
PERIOD...WITH A SERIES OF FAST MOVING 500HPA SHORT WVS AND MODEST
SFC SYSTEMS...IN A RELATIVELY MOISTURE STARVED ENVIRONMENT.
THE STRONGEST OF THE SHORT WVS MVS FM UPPER GRTLKS TNGT...CROSSES
THE REGION TUES...AND EXISTS THE RGN TUES NT. AS FCA IS IN SFC
GRADIENT BTWN DEPARTING SFC LOW IN GULF OF MAINE AND SFC HIGH
BUILDING SE FM ONTARIO WINDS AND CAA WILL INCR TNGT. CLOUDS AND
PCPN ALONG COAST WILL BE GONE BY EVENING W/CLEARING. LATER AT
NIGHT CLOUDS AND SCT -SHSN WILL INCR MAINLY W PRTNS OF AREA AS
500HPA SHORT WV AND 2NDRY CDFNT APPROACH FM GRTLKS.
CHRISTMAS EVE THE 500HPA TROF WILL CROSS THE RGN IN CAA...AND
BRING VRBL CLOUDS AND SCT -SHSN...HWVR WITH SFC FLOW N-NE
ANY INTERACTIONS W/GRTLKS WILL BE TO AREAS WELL TO OUR WEST.
500HPA TROF EXITS RGN TUES EVNG...AS ARCTIC SFC HIGH DROPS INTO E
GRTLKS AND NYS OVERNIGHT. IDEAL RADIATION CONDS WILL SET UP AS SKIES
CLEAR...WINDS BCM LIGHT AND ONE OF THE LONGEST NIGHTS OF THE YEAR
WITH ALMOST 15 HOURS OF DARKNESS...WILL ALLOW TEMPS TO PLUNGE.
WHERE SNOW COVER REMAINS THE PLUNGE WILL BE EVEN GREATER WITH LOWS
BY CHRISTMAS MORNING FALLING TO -20F IN PARTS OF THE ADRDKS...WHILE
FURTHER SOUTH LOWS WILL BE CLOSER TO +10F.
AFTER A CHILLY START CHRISTMAS DAY 500HPA RIDGE AND SFC HIGH SLIDE
OFFSHORE...AND TEMPS REBOUND TO TEENS AND 20S. BY AFTN THE PATTERN
THAT WILL DOMINATE THE REST OF THE WEEK AND MAYBE THE YEAR WILL
SET UP.
RGN IS IN FAST W TO NW 500HPA...AND A PARADE OF SHRT WAVES AND
CLIPPER TYPE LOWS MOVE THROUGH. THE FIRST OF THESE MOVES INTO THE
GRTLKS CHRISTMAS DAY...WITH SOME INCRG CLOUDS IN THE AFTN. WED NT ITS
WK SFC SYSTEM PUSHES A WMFNT THRU RGN AND A CDFNT THU. ITS MAIN
IMPACTS WILL NE INCR CLOUDS WED NT WITH A SCT -SHSN THU AND A BRIEF
LK EFFECT RESPONSE THU AND THU EVNG INTO W MHWK VLY AND W ADRNDKS.
LATER THU NT SFC HIGH WILL RIDGE INTO RGN AS NEXT SHORT WV TEES
UP OVER MICHIGAN. TEMPS THU WILL RETURN TO NR NORMALS
&&
.LONG TERM /FRIDAY THROUGH SUNDAY/...
THE LAST WEEKEND OF 2013 WILL KEEP THE FAST 500 HPA FLOW ACROSS N
TIER OF USA...AND THE PARADE OF SHORT WVS AND WEAK SYSTEMS. WK SFC
HIGH CRESTS ACROSS GRTLKS FRI...AS ANOTHER 500HPA SHORT WV RACES
THROUGH. DURING FRI EVENING A WK WMFNT SETS UP FM NW TO SE W OF
FCA. IN SPITE OF ALL THESE FEATURES SO LITTLE MOISTURE NOT MUCH
MORE THAN VRBL CLOUDS AND SCT FLURRIES N TIER.
SAT A STRONGER SHORT WV MVS INTO W GRTLKS WITH CLIPPER TYPE SFC
LOW. BY EVENING IT PUSHES WMFNT INTO FCA AND OVERRUNING CLOUDS BCM
MORE EXTENSIVE UPSTREAM AND SPILL SE INTO FCA. BUT IN THIS CASE
BULK OF DYNAMICS AND MOISTURE REMAIN N IN CANADA AND MAINLY
CLOUDS AND CHC -SN IN FAR N TIER OF FCA. BY END OF PD STRONG
CDFNT EITHER MOVES THROUGH...(GFS) OR IS ABOUT TO (ECWMF) ABOUT 12
HOUR DIFFERENCE AND NOT AS COLD AN AIR MASS ON ECMWF. OTHER THAN
THIS SLIGHT TIMING DIFFERENCE THE GFS/ECMWF ARE IN VERY GOOD
AGREEMENT DURING THE EFP. THIS IS SAME SCENARIO REFLECTED IN HPC
GUID...AND THEY LEAN TWRD THE FAST GFS CDFNT SCENARIO. IN ANY CASE
BY END OF PERIOD TEMPS DROP TO BLOW NORMALS.
GEFS PLUMES HAVE A FEW MEMBERS WITH 0.10 TO 0.20 QPF SIGNAL IN
THE THU/FRI TIME PERIOD...OTHERWISE MOST ARE FLAT LINED TILL NEXT
MONDAY IN WHEN ABOUT HALF START SHOWING A 2-4 INCH TYPE SNOW
EVENT...WHICH NONE OF THE DETERMINISTIC MODELS DO.
SINCE THERE`S LITTLE DIVERGENCE IN THE GUID DURING THIS PERIOD WILL
POPULATE WITH HPC.
&&
.AVIATION /09Z MONDAY THROUGH FRIDAY/...
FLYING CONDITIONS VARYING QUITE A BIT ACROSS THE AREA...WITH KGFL
SOCKED IN WITH LIFR FOG AND LOW STRATUS ON THE COLD SIDE OF A
FRONTAL BOUNDARY...WHILE KPOU/KPSF ARE SOUTH OF THIS FRONT WITH
VFR CONDITIONS. KALB IS RIGHT ON THE BORDER NEAR THE BOUNDARY...AND
HAS SEEN VFR CONDITIONS DROP TO MVFR. ALL SITES ARE SEEING LIGHT
TO CALM WINDS AND THIS LOOKS TO CONTINUE THROUGH THE OVERNIGHT
HOURS.
A WAVE OF LOW PRESSURE WILL LIFT NORTHEASTWARD ALONG THE FRONTAL
BOUNDARY WHICH WILL RESULT IN ANOTHER ROUND OF LIGHT STEADY RAINFALL
STARTING BETWEEN 08Z-10Z. CONDITIONS ARE EXPECTED TO LOWER TO IFR
BEFORE 12Z AT ALL TERMINALS. WILL CONTINUE TO MENTION IFR
CONDITIONS THROUGH AROUND 18Z OR 19Z...WITH RAIN THEN ENDING AND
DRIER AIR STARTING TO WORK THEREAFTER WITH IMPROVING CONDITIONS.
ALL SITES LOOK TO BE VFR BY THE EVENING HOURS...WITH A WESTERLY
BREEZE DEVELOPING. A FEW GUSTS TOWARDS 20 KTS WILL BE POSSIBLE FOR
KALB/KPSF FOR MONDAY EVENING.
OUTLOOK...
TUESDAY NIGHT AND CHRISTMAS DAY: NO OPERATIONAL IMPACT. NO SIG WX.
WEDNESDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHSN.
THURSDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA...SHSN.
THURSDAY NIGHT THROUGH SATURDAY: NO OPERATIONAL IMPACT. NO SIG WX.
&&
.HYDROLOGY...
LOW PRESSURE WILL RIPPLE UP THE EASTERN SEABOARD TODAY...BRINGING
UP TO A HALF INCH OF QPF TO AREAS SOUTH AND EAST OF ALBANY...WITH
THE GREATEST AMOUNTS IN LITCHFIELD AND DUTCHESS COUNTIES. THIS
WILL ADD TO STREAM FLOWS AND WITHIN BANK RISES IN THESE AREAS. HOWEVER
EVEN THOUGH THEY HAD TOTAL SNOW MELT...THEY HAD LITTLE RAINFALL
WITH THE PREVIOUS SYSTEM...AND FLOODING IS NOT EXPECTED.
COLDER DRIER AIR WILL FILTER BACK INTO THE REGION TONIGHT...WITH
MUCH COLDER TEMPERATURES AND MAINLY DRY CONDITIONS THE REST OF
THE WEEK. THERE MAY BE SCATTERED SNOW SHOWERS...BUT OF LITTLE
CONSEQUENCE TO RIVERS AND STREAMS.
STREAM FLOWS WILL SLOW AS RUN OFF AND SNOW MELT END. ICE FORMATION
WILL START ANEW BY CHRISTMAS.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...SNYDER
NEAR TERM...FRUGIS
SHORT TERM...SNYDER
LONG TERM...SNYDER
AVIATION...FRUGIS
HYDROLOGY...SNYDER
AREA FORECAST DISCUSSION
NWS ALBANY NY
329 AM EST MON DEC 23 2013
.SYNOPSIS...
LOW PRESSURE WILL MOVE UP THE SEASON SEABOARD TODAY...BRINGING ONE
MORE ROUND OF RAIN TO SOUTHERN NEW ENGLAND AND IN NEW YORK FROM
THE CAPITAL DISTRICT SOUTH. IN ITS WAKE COLD AIR WILL FILTER INTO
OUR REGION THIS AFTERNOON AS WINDS INCREASE. EVEN COLDER AIR WILL
MOVE INTO THE REGION AS HIGH PRESSURE MOVES FROM ONTARIO TONIGHT
TO NEW YORK AND NEW ENGLAND CHRISTMAS DAY. THE REST OF THE WEEK
WILL FEATURE A SERIES OF WEAK FAST MOVING WEATHER SYSTEMS...WITH
VARIABLE CLOUDINESS...SCATTERED SNOW SHOWERS AND SEASONABLE
TEMPERATURES.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 300 AM EST...NEARLY STATIONARY FRONTAL BOUNDARY CONTINUES TO
BE SITUATED FROM WEST TO EAST ACROSS THE CENTRAL PORTION OF THE CWA
EARLY THIS MORNING. TO THE NORTH OF THIS BOUNDARY...IMPRESSIVE CAD
CONTINUES ACROSS THE LAKE GEORGE/SARATOGA REGION...WITH TEMPS CLOSE
TO FREEZING. MEANWHILE...OTHER AREAS NORTH OF THE BOUNDARY GENERALLY
ARE IN THE MID 30S TO MID 40S. SOUTH OF THE BOUNDARY...TEMPS ARE IN
THE 40S ACROSS THE LOWER ELEVATIONS...AND 50S OVER THE HIGH TERRAIN.
THESE WARM TEMPS OVER THE HIGHER ELEVATIONS WILL START TO LOWER OVER
THE NEXT FEW HOURS...AS FORECAST MODEL SOUNDINGS SHOWS THE
IMPRESSIVE WARM NOSE AT AROUND 900-950 HPA IS FINALLY BEING PUSHED
AWAY FROM THE REGION THANKS A STRONG SW FLOW ALOFT.
STILL...THE AIR MOVING IN THIS MORNING ISN/T OVERLY CHILLY JUST
YET...AS OUR REGION IS BEING INFLUENCED BY A STRONG MEDIRONDAL FLOW
AHEAD OF A DEEP UPPER LEVEL TROUGH SITUATED OVER THE CENTRAL PORTION
OF THE US. IN ADDITION...THIS FLOW IS CONTINUING TO TRANSPORT PLENTY
OF MID/HIGH LEVEL MOISTURE STRAIGHT OUT OF PACIFIC AND GULF OF
MEXICO TOWARDS OUR AREA. PWATS WILL CONTINUE TO BE ABOVE NORMAL
TODAY...WITH FORECASTED VALUES EXPECTED TO BE AROUND AN INCH...WHICH
IS ABOUT 2 STD ABOVE NORMAL.
DURING THE DAY TODAY...AN AREA OF LOW PRESSURE /DEVELOPING ACROSS
THE SOUTHEAST US EARLY THIS MORNING/ WILL RIDE NORTHWARD ALONG THE
EASTERN SEABOARD. REGIONAL RADAR ALREADY SHOWS A SOLID AREA OF
STEADY RAIN AHEAD OF THIS DEVELOPING SYSTEM OVER THE MID ATLANTIC
STATES...AND THIS WILL BE RIDING FROM SOUTHWEST TO NORTHEAST ACROSS
THE REGION TODAY. THE 00Z NAM/GFS/ECMWF AND 05Z 3KM HRRR ALL SHOW
THIS PRECIP MOVING FROM SOUTHWEST TO NORTHEAST ACROSS OUR REGION
BETWEEN JUST SHORTLY BEFORE SUNRISE AND THROUGH THE MORNING HOURS.
THE BEST CHC FOR PRECIP WILL BE ACROSS THE SOUTHERN AND EASTERN
PORTION OF THE CWA...WHERE UP TO AROUND A HALF INCH OF RAIN WILL
FALL FOR LITCHFIELD COUNTY.
PRECIP WILL FALL MAINLY IN THE FORM OF LIQUID RAIN. WITH CONTINUED
MARGINAL TEMPS IN THE LAKE GEORGE/SARATOGA REGION...IT/S POSSIBLE
THAT THERE MAY INITIALLY BE SOME SPOTTY FREEZING RAIN ONCE THE
PRECIP MOVES IN...BUT TEMPS SHOULD WARM UP ENOUGH TO AVOID A
PROLONGED PERIOD OF FREEZING RAIN THERE. OTHERWISE...THE ONLY OTHER
PLACE THERE COULD BE SOME WINTRY PRECIP IS THE FAR NORTHWESTERN
ADIRONDACKS...WHERE COLDER AIR SNEAKING IN ALOFT MAY ALLOW FOR THE
PRECIP TO CHANGEOVER TO SLEET/SNOW. LITTLE QPF IS EXPECTED THAT FAR
NW...SO ANY ACCUMULATION WILL BE LIMITED TO JUST A COATING.
MOST AREAS LOOK TO SEE MAX TEMPS IN THE MORNING HOURS...WITH TEMPS
RANGING FROM THE MID 30S IN THE ADIRONDACKS TO THE MID 50S IN THE
MID HUDSON VALLEY AND NW CT. MOST TEMPS WILL HOLD STEADY THIS
MORNING...ALTHOUGH THE CAD IN THE LAKE GEORGE/SARATOGA AREA SHOULD
GIVE WAY ENOUGH FOR TEMPS THERE TO RISE TOWARDS THE UPPER 30S TO LOW
40S BY THE LATE MORNING HOURS.
BY THE AFTN...STEADY PRECIP WILL BE MOVING ACROSS NEW ENGLAND...AND
THERE WILL BE JUST A FEW LINGERING SHOWERS...MAINLY ACROSS THE
HIGHER ELEVATIONS. WITH COLDER AIR SURGING IN ON WESTERLY
WINDS...TEMPS WILL TUMBLE ACROSS MOST AREAS DURING THE AFTN
HOURS...FALLING FROM THE 40S INTO THE 30S ACROSS MUCH OF THE REGION.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
GENERALLY THE MODEL SUITE (GEM/GFS/NAM/ECMWF) IS IN AGREEMENT DURING THIS
PERIOD...WITH A SERIES OF FAST MOVING 500HPA SHORT WVS AND MODEST
SFC SYSTEMS...IN A RELATIVELY MOISTURE STARVED ENVIRONMENT.
THE STRONGEST OF THE SHORT WVS MVS FM UPPER GRTLKS TNGT...CROSSES
THE REGION TUES...AND EXISTS THE RGN TUES NT. AS FCA IS IN SFC
GRADIENT BTWN DEPARTING SFC LOW IN GULF OF MAINE AND SFC HIGH
BUILDING SE FM ONTARIO WINDS AND CAA WILL INCR TNGT. CLOUDS AND
PCPN ALONG COAST WILL BE GONE BY EVENING W/CLEARING. LATER AT
NIGHT CLOUDS AND SCT -SHSN WILL INCR MAINLY W PRTNS OF AREA AS
500HPA SHORT WV AND 2NDRY CDFNT APPROACH FM GRTLKS.
CHRISTMAS EVE THE 500HPA TROF WILL CROSS THE RGN IN CAA...AND
BRING VRBL CLOUDS AND SCT -SHSN...HWVR WITH SFC FLOW N-NE
ANY INTERACTIONS W/GRTLKS WILL BE TO AREAS WELL TO OUR WEST.
500HPA TROF EXITS RGN TUES EVNG...AS ARCTIC SFC HIGH DROPS INTO E
GRTLKS AND NYS OVERNIGHT. IDEAL RADIATION CONDS WILL SET UP AS SKIES
CLEAR...WINDS BCM LIGHT AND ONE OF THE LONGEST NIGHTS OF THE YEAR
WITH ALMOST 15 HOURS OF DARKNESS...WILL ALLOW TEMPS TO PLUNGE.
WHERE SNOW COVER REMAINS THE PLUNGE WILL BE EVEN GREATER WITH LOWS
BY CHRISTMAS MORNING FALLING TO -20F IN PARTS OF THE ADRDKS...WHILE
FURTHER SOUTH LOWS WILL BE CLOSER TO +10F.
AFTER A CHILLY START CHRISTMAS DAY 500HPA RIDGE AND SFC HIGH SLIDE
OFFSHORE...AND TEMPS REBOUND TO TEENS AND 20S. BY AFTN THE PATTERN
THAT WILL DOMINATE THE REST OF THE WEEK AND MAYBE THE YEAR WILL
SET UP.
RGN IS IN FAST W TO NW 500HPA...AND A PARADE OF SHRT WAVES AND
CLIPPER TYPE LOWS MOVE THROUGH. THE FIRST OF THESE MOVES INTO THE
GRTLKS CHRISTMAS DAY...WITH SOME INCRG CLOUDS IN THE AFTN. WED NT ITS
WK SFC SYSTEM PUSHES A WMFNT THRU RGN AND A CDFNT THU. ITS MAIN
IMPACTS WILL NE INCR CLOUDS WED NT WITH A SCT -SHSN THU AND A BRIEF
LK EFFECT RESPONSE THU AND THU EVNG INTO W MHWK VLY AND W ADRNDKS.
LATER THU NT SFC HIGH WILL RIDGE INTO RGN AS NEXT SHORT WV TEES
UP OVER MICHIGAN. TEMPS THU WILL RETURN TO NR NORMALS
&&
.LONG TERM /FRIDAY THROUGH SUNDAY/...
THE LAST WEEKEND OF 2013 WILL KEEP THE FAST 500 HPA FLOW ACROSS N
TIER OF USA...AND THE PARADE OF SHORT WVS AND WEAK SYSTEMS. WK SFC
HIGH CRESTS ACROSS GRTLKS FRI...AS ANOTHER 500HPA SHORT WV RACES
THROUGH. DURING FRI EVENING A WK WMFNT SETS UP FM NW TO SE W OF
FCA. IN SPITE OF ALL THESE FEATURES SO LITTLE MOISTURE NOT MUCH
MORE THAN VRBL CLOUDS AND SCT FLURRIES N TIER.
SAT A STRONGER SHORT WV MVS INTO W GRTLKS WITH CLIPPER TYPE SFC
LOW. BY EVENING IT PUSHES WMFNT INTO FCA AND OVERRUNING CLOUDS BCM
MORE EXTENSIVE UPSTREAM AND SPILL SE INTO FCA. BUT IN THIS CASE
BULK OF DYNAMICS AND MOISTURE REMAIN N IN CANADA AND MAINLY
CLOUDS AND CHC -SN IN FAR N TIER OF FCA. BY END OF PD STRONG
CDFNT EITHER MOVES THROUGH...(GFS) OR IS ABOUT TO (ECWMF) ABOUT 12
HOUR DIFFERENCE AND NOT AS COLD AN AIR MASS ON ECMWF. OTHER THAN
THIS SLIGHT TIMING DIFFERENCE THE GFS/ECMWF ARE IN VERY GOOD
AGREEMENT DURING THE EFP. THIS IS SAME SCENARIO REFLECTED IN HPC
GUID...AND THEY LEAN TWRD THE FAST GFS CDFNT SCENARIO. IN ANY CASE
BY END OF PERIOD TEMPS DROP TO BLOW NORMALS.
GEFS PLUMES HAVE A FEW MEMBERS WITH 0.10 TO 0.20 QPF SIGNAL IN
THE THU/FRI TIME PERIOD...OTHERWISE MOST ARE FLAT LINED TILL NEXT
MONDAY IN WHEN ABOUT HALF START SHOWING A 2-4 INCH TYPE SNOW
EVENT...WHICH NONE OF THE DETERMINISTIC MODELS DO.
SINCE THERE`S LITTLE DIVERGENCE IN THE GUID DURING THIS PERIOD WILL
POPULATE WITH HPC.
&&
.AVIATION /08Z MONDAY THROUGH FRIDAY/...
FLYING CONDITIONS VARYING QUITE A BIT ACROSS THE AREA...WITH KGFL
SOCKED IN WITH LIFR FOG AND LOW STRATUS ON THE COLD SIDE OF A
FRONTAL BOUNDARY...WHILE KPOU/KPSF ARE SOUTH OF THIS FRONT WITH
VFR CONDITIONS. KALB IS RIGHT ON THE BORDER NEAR THE BOUNDARY...AND
HAS SEEN VFR CONDITIONS DROP TO MVFR. ALL SITES ARE SEEING LIGHT
TO CALM WINDS AND THIS LOOKS TO CONTINUE THROUGH THE OVERNIGHT
HOURS.
A WAVE OF LOW PRESSURE WILL LIFT NORTHEASTWARD ALONG THE FRONTAL
BOUNDARY WHICH WILL RESULT IN ANOTHER ROUND OF LIGHT STEADY RAINFALL
STARTING BETWEEN 08Z-10Z. CONDITIONS ARE EXPECTED TO LOWER TO IFR
BEFORE 12Z AT ALL TERMINALS. WILL CONTINUE TO MENTION IFR
CONDITIONS THROUGH AROUND 18Z OR 19Z...WITH RAIN THEN ENDING AND
DRIER AIR STARTING TO WORK THEREAFTER WITH IMPROVING CONDITIONS.
ALL SITES LOOK TO BE VFR BY THE EVENING HOURS...WITH A WESTERLY
BREEZE DEVELOPING. A FEW GUSTS TOWARDS 20 KTS WILL BE POSSIBLE FOR
KALB/KPSF FOR MONDAY EVENING.
OUTLOOK...
MONDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA...SHSN.
TUESDAY: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHSN.
TUESDAY NIGHT TO FRIDAY: NO OPERATIONAL IMPACT. NO SIG WX.
&&
.HYDROLOGY...
LOW PRESSURE WILL RIPPLE UP THE EASTERN SEABOARD TODAY...BRINGING
UP TO A HALF INCH OF QPF TO AREAS SOUTH AND EAST OF ALBANY...WITH
THE GREATEST AMOUNTS IN LITCHFIELD AND DUTCHESS COUNTIES. THIS
WILL ADD TO STREAM FLOWS AND WITHIN BANK RISES IN THESE AREAS. HOWEVER
EVEN THOUGH THEY HAD TOTAL SNOW MELT...THEY HAD LITTLE RAINFALL
WITH THE PREVIOUS SYSTEM...AND FLOODING IS NOT EXPECTED.
COLDER DRIER AIR WILL FILTER BACK INTO THE REGION TONIGHT...WITH
MUCH COLDER TEMPERATURES AND MAINLY DRY CONDITIONS THE REST OF
THE WEEK. THERE MAY BE SCATTERED SNOW SHOWERS...BUT OF LITTLE
CONSEQUENCE TO RIVERS AND STREAMS.
STREAM FLOWS WILL SLOW AS RUN OFF AND SNOW MELT END. ICE FORMATION
WILL START ANEW BY CHRISTMAS.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...SNYDER
NEAR TERM...FRUGIS
SHORT TERM...SNYDER
LONG TERM...SNYDER
AVIATION...FRUGIS
HYDROLOGY...SNYDER
AREA FORECAST DISCUSSION
NWS ALBANY NY
157 AM EST MON DEC 23 2013
.SYNOPSIS...
LOW PRESSURE WILL MOVE UP THE SEASON SEABOARD TODAY...BRINGING ONE
MORE ROUND OF RAIN TO SOUTHERN NEW ENGLAND AND IN NEW YORK FROM
THE CAPITAL DISTRICT SOUTH. IN ITS WAKE COLD AIR WILL FILTER INTO
OUR REGION THIS AFTERNOON AS WINDS INCREASE. EVEN COLDER AIR WILL
MOVE INTO THE REGION AS HIGH PRESSURE MOVES FROM ONTARIO TONIGHT
TO NEW YORK AND NEW ENGLAND CHRISTMAS DAY. THE REST OF THE WEEK
WILL FEATURE A SERIES OF WEAK FAST MOVING WEATHER SYSTEMS...WITH
VARIABLE CLOUDINESS...SCATTERED SNOW SHOWERS AND SEASONABLE
TEMPERATURES.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 1220 AM EST...TEMPERATURES CONTINUE TO BE HIGHLY VARIABLE
ACROSS THE REGION...AS A NEARLY STATIONARY BOUNDARY IS SITUATED
ACROSS CENTRAL PARTS OF THE AREA. TEMPS CONTINUE TO BE IN THE
UPPER 50S ACROSS SOUTHERN AREAS...WITH TEMPS NEAR FREEZING IN THE
LAKE GEORGE/SARATOGA REGION...AS THE COLD NORTHERLY FLOW CONTINUES
ACROSS THAT REGION. TEMPS IN THE CAPITAL REGION HAVE BEEN RATHER
VARIABLE...AND HAVE CURRENTLY DROPPED INTO THE 40S.
NO PRECIP IS CURRENTLY OCCURRING OVER OUR REGION AND LOCAL AND
UPSTREAM RADARS SHOW VERY LITTLE. HOWEVER...A WAVE OF LOW
PRESSURE IS FORECAST TO LIFT NORTHEASTWARD ALONG THE FRONTAL
BOUNDARY LATE TONIGHT INTO MONDAY...BRINGING ANOTHER ROUND OF
RAINFALL TO AREAS MAINLY FROM THE CAPITAL REGION SOUTH AND EAST.
THE 01Z 3KM HRRR CONTINUES TO SHOW PRECIP DEVELOPING AND EXPANDING
ACROSS OUR REGION AFTER ABOUT 08Z-09Z. HAVE ADJUSTED POPS
ACCORDING TO THE LATEST GUIDANCE...WHICH HAS RAIN DEVELOPING FROM
SOUTHWEST TO NORTHEAST LATE TONIGHT. MILD TEMPERATURES SOUTH AND
EAST OF THE CAPITAL REGION WILL SLOWLY DROP LATE TONIGHT AS THE
FRONTAL BOUNDARY EASES SOUTHWARD. FURTHER NORTH...TEMPS WILL
GENERALLY HOLD STEADY THROUGH THE REMAINDER OF THE OVERNIGHT.
AFOREMENTIONED DISTURBANCE LOOKS TO BRING ONE MORE ROUND OF
RAIN...MAINLY FROM ALBANY AND POINTS SOUTHWARD ON MONDAY. WE ARE
LOOKING FOR A QUARTER TO HALF AN INCH OF RAINFALL WITH THIS WAVE
WITH ONLY A CHANCE OF RAIN NORTH AND WEST OF ALBANY.
TEMPERATURES WILL SLOWLY COOL OFF AS THE COLD FRONT CONTINUES TO
SLIP SLOWLY SOUTH AND EAST OF OUR FORECAST AREA. H850
TEMPERATURES...WHICH ROSE OVER +10C OVER MUCH OF OUR AREA ON
SUNDAY...WILL COOL BACK TO MUCH MORE NORMAL DECEMBER LEVELS...BELOW
0C BY LATE MONDAY.
ANY LEFTOVER PRECIPITATION SHOULD CHANGE BACK TO SNOW NORTH AND WEST
OF ALBANY BY LATE MONDAY...PROBABLY NOT FROM ALBANY SOUTHWARD.
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
GENERALLY THE MODEL SUITE (GEM/GFS/NAM/ECMWF) IS IN AGREEMENT DURING THIS
PERIOD...WITH A SERIES OF FAST MOVING 500HPA SHORT WVS AND MODEST
SFC SYSTEMS...IN A RELATIVELY MOISTURE STARVED ENVIRONMENT.
THE STRONGEST OF THE SHORT WVS MVS FM UPPER GRTLKS TNGT...CROSSES
THE REGION TUES...AND EXISTS THE RGN TUES NT. AS FCA IS IN SFC
GRADIENT BTWN DEPARTING SFC LOW IN GULF OF MAINE AND SFC HIGH
BUILDING SE FM ONTARIO WINDS AND CAA WILL INCR TNGT. CLOUDS AND
PCPN ALONG COAST WILL BE GONE BY EVENING W/CLEARING. LATER AT
NIGHT CLOUDS AND SCT -SHSN WILL INCR MAINLY W PRTNS OF AREA AS
500HPA SHORT WV AND 2NDRY CDFNT APPROACH FM GRTLKS.
CHRISTMAS EVE THE 500HPA TROF WILL CROSS THE RGN IN CAA...AND
BRING VRBL CLOUDS AND SCT -SHSN...HWVR WITH SFC FLOW N-NE
ANY INTERACTIONS W/GRTLKS WILL BE TO AREAS WELL TO OUR WEST.
500HPA TROF EXITS RGN TUES EVNG...AS ARCTIC SFC HIGH DROPS INTO E
GRTLKS AND NYS OVERNIGHT. IDEAL RADIATION CONDS WILL SET UP AS SKIES
CLEAR...WINDS BCM LIGHT AND ONE OF THE LONGEST NIGHTS OF THE YEAR
WITH ALMOST 15 HOURS OF DARKNESS...WILL ALLOW TEMPS TO PLUNGE.
WHERE SNOW COVER REMAINS THE PLUNGE WILL BE EVEN GREATER WITH LOWS
BY CHRISTMAS MORNING FALLING TO -20F IN PARTS OF THE ADRDKS...WHILE
FURTHER SOUTH LOWS WILL BE CLOSER TO +10F.
AFTER A CHILLY START CHRISTMAS DAY 500HPA RIDGE AND SFC HIGH SLIDE
OFFSHORE...AND TEMPS REBOUND TO TEENS AND 20S. BY AFTN THE PATTERN
THAT WILL DOMINATE THE REST OF THE WEEK AND MAYBE THE YEAR WILL
SET UP.
RGN IS IN FAST W TO NW 500HPA...AND A PARADE OF SHRT WAVES AND
CLIPPER TYPE LOWS MOVE THROUGH. THE FIRST OF THESE MOVES INTO THE
GRTLKS CHRISTMAS DAY...WITH SOME INCRG CLOUDS IN THE AFTN. WED NT ITS
WK SFC SYSTEM PUSHES A WMFNT THRU RGN AND A CDFNT THU. ITS MAIN
IMPACTS WILL NE INCR CLOUDS WED NT WITH A SCT -SHSN THU AND A BRIEF
LK EFFECT RESPONSE THU AND THU EVNG INTO W MHWK VLY AND W ADRNDKS.
LATER THU NT SFC HIGH WILL RIDGE INTO RGN AS NEXT SHORT WV TEES
UP OVER MICHIGAN. TEMPS THU WILL RETURN TO NR NORMALS
&&
.LONG TERM /FRIDAY THROUGH SUNDAY/...
THE EXTENDED PERIOD CONTINUES TO LOOK MAINLY DRY...WITH THE ONLY
CHANCE FOR MEASURABLE PRECIPITATION BEING IN THE FORM OF LAKE EFFECT
SNOW SHOWERS IN PORTIONS OF THE WESTERN ADIRONDACKS...THROUGH
FRIDAY NIGHT. A WEAK CLIPPER-LIKE LOW IS EXPECTED TO PASS TO OUR
NORTH LATE SUNDAY...PROVIDING LITTLE IN THE WAY OF PRECIPITATION.
TEMPERATURES DURING THIS PERIOD WILL BE NR TO SLIGHT ABV
NORMALS.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
FLYING CONDITIONS VARYING QUITE A BIT ACROSS THE AREA...WITH KGFL
SOCKED IN WITH LIFR FOG AND LOW STRATUS ON THE COLD SIDE OF A
FRONTAL BOUNDARY...WHILE KPOU/KPSF ARE SOUTH OF THIS FRONT WITH
VFR CONDITIONS. KALB IS RIGHT ON THE BORDER NEAR THE BOUNDARY...AND
HAS SEEN VFR CONDITIONS DROP TO MVFR. ALL SITES ARE SEEING LIGHT
TO CALM WINDS AND THIS LOOKS TO CONTINUE THROUGH THE OVERNIGHT
HOURS.
A WAVE OF LOW PRESSURE WILL LIFT NORTHEASTWARD ALONG THE FRONTAL
BOUNDARY WHICH WILL RESULT IN ANOTHER ROUND OF LIGHT STEADY RAINFALL
STARTING BETWEEN 08Z-10Z. CONDITIONS ARE EXPECTED TO LOWER TO IFR
BEFORE 12Z AT ALL TERMINALS. WILL CONTINUE TO MENTION IFR
CONDITIONS THROUGH AROUND 18Z OR 19Z...WITH RAIN THEN ENDING AND
DRIER AIR STARTING TO WORK THEREAFTER WITH IMPROVING CONDITIONS.
ALL SITES LOOK TO BE VFR BY THE EVENING HOURS...WITH A WESTERLY
BREEZE DEVELOPING. A FEW GUSTS TOWARDS 20 KTS WILL BE POSSIBLE FOR
KALB/KPSF FOR MONDAY EVENING.
OUTLOOK...
MONDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA...SHSN.
TUESDAY: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHSN.
TUESDAY NIGHT TO FRIDAY: NO OPERATIONAL IMPACT. NO SIG WX.
&&
.HYDROLOGY...
LOW PRESSURE WILL RIPPLE UP THE EASTERN SEABOARD TODAY...BRINGING
UP TO A HALF INCH OF QPF TO AREAS SOUTH AND EAST OF ALBANY...WITH
THE GREATEST AMOUNTS IN LITCHFIELD AND DUTCHESS COUNTIES. THIS
WILL ADD TO STREAM FLOWS AND WITHIN BANK RISES IN THESE AREAS. HOWEVER
EVEN THOUGH THEY HAD TOTAL SNOW MELT...THEY HAD LITTLE RAINFALL
WITH THE PREVIOUS SYSTEM...AND FLOODING IS NOT EXPECTED.
COLDER DRIER AIR WILL FILTER BACK INTO THE REGION TONIGHT...WITH
MUCH COLDER TEMPERATURES AND MAINLY DRY CONDITIONS THE REST OF
THE WEEK. THERE MAY BE SCATTERED SNOW SHOWERS...BUT OF LITTLE
CONSEQUENCE TO RIVERS AND STREAMS.
STREAM FLOWS WILL SLOW AS RUN OFF AND SNOW MELT END. ICE FORMATION
WILL START ANEW BY CHRISTMAS.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...SNYDER
NEAR TERM...FRUGIS/HWJIV/JPV
SHORT TERM...SNYDER
LONG TERM...ELH
AVIATION...FRUGIS
HYDROLOGY...SNYDER
AREA FORECAST DISCUSSION
NWS ALBANY NY
1220 AM EST MON DEC 23 2013
.SYNOPSIS...
A NEARLY STATIONARY FRONT FROM CENTRAL NEW YORK TO THE MAINE COAST
WILL BEGIN TO SHIFT SLOWLY SOUTHWARD TONIGHT. ONE MORE WAVE OF LOW
PRESSURE WILL RIDE ALONG IT BRINGING ONE MORE SHOT OF RAINFALL
MAINLY FROM CAPITAL REGION SOUTHWARD. COLDER AIR WILL FILTER IN
MONDAY NIGHT. IT WILL STAY COLD MUCH OF THE UPCOMING WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 1220 AM EST...TEMPERATURES CONTINUE TO BE HIGHLY VARIABLE
ACROSS THE REGION...AS A NEARLY STATIONARY BOUNDARY IS SITUATED
ACROSS CENTRAL PARTS OF THE AREA. TEMPS CONTINUE TO BE IN THE
UPPER 50S ACROSS SOUTHERN AREAS...WITH TEMPS NEAR FREEZING IN THE
LAKE GEORGE/SARATOGA REGION...AS THE COLD NORTHERLY FLOW CONTINUES
ACROSS THAT REGION. TEMPS IN THE CAPITAL REGION HAVE BEEN RATHER
VARIABLE...AND HAVE CURRENTLY DROPPED INTO THE 40S.
NO PRECIP IS CURRENTLY OCCURRING OVER OUR REGION AND LOCAL AND
UPSTREAM RADARS SHOW VERY LITTLE. HOWEVER...A WAVE OF LOW
PRESSURE IS FORECAST TO LIFT NORTHEASTWARD ALONG THE FRONTAL
BOUNDARY LATE TONIGHT INTO MONDAY...BRINGING ANOTHER ROUND OF
RAINFALL TO AREAS MAINLY FROM THE CAPITAL REGION SOUTH AND EAST.
THE 01Z 3KM HRRR CONTINUES TO SHOW PRECIP DEVELOPING AND EXPANDING
ACROSS OUR REGION AFTER ABOUT 08Z-09Z. HAVE ADJUSTED POPS
ACCORDING TO THE LATEST GUIDANCE...WHICH HAS RAIN DEVELOPING FROM
SOUTHWEST TO NORTHEAST LATE TONIGHT. MILD TEMPERATURES SOUTH AND
EAST OF THE CAPITAL REGION WILL SLOWLY DROP LATE TONIGHT AS THE
FRONTAL BOUNDARY EASES SOUTHWARD. FURTHER NORTH...TEMPS WILL
GENERALLY HOLD STEADY THROUGH THE REMAINDER OF THE OVERNIGHT.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH WEDNESDAY/...
AFOREMENTIONED DISTURBANCE LOOKS TO BRING ONE MORE ROUND OF
RAIN...MAINLY FROM ALBANY AND POINTS SOUTHWARD ON MONDAY. WE ARE
LOOKING FOR A QUARTER TO HALF AN INCH OF RAINFALL WITH THIS WAVE
WITH ONLY A CHANCE OF RAIN NORTH AND WEST OF ALBANY.
TEMPERATURES WILL SLOWLY COOL OFF AS THE COLD FRONT CONTINUES TO
SLIP SLOWLY SOUTH AND EAST OF OUR FORECAST AREA. H850
TEMPERATURES...WHICH ROSE OVER +10C OVER MUCH OF OUR AREA ON
SUNDAY...WILL COOL BACK TO MUCH MORE NORMAL DECEMBER LEVELS...BELOW
0C BY LATE MONDAY.
ANY LEFTOVER PRECIPITATION SHOULD CHANGE BACK TO SNOW NORTH AND WEST
OF ALBANY BY LATE MONDAY...PROBABLY NOT FROM ALBANY SOUTHWARD.
THE WAVE AND FRONT CLEAR THE REGION MONDAY NIGHT. COLD AIR WORKING
OVER THE LAKES LOOKS TO PERHAPS TRIGGER A LAKE RESPONSE. HOWEVER THE
CSTAR-RESEARCH DRIVEN KVIE INDICATED NOT MUCH CHANCE FOR A
SIGNIFICANT BAND AS THE WIND SHEAR WAS TOO GREAT (WNW WIND SURFACE
WSW ALOFT) AND THE CAPPING INVERSION WAS ONLY ABOUT 1KM...WHICH
WOULD INHIBIT SNOW GROWTH. BOTTOM LINE...ANY LAKE EFFECT WOULD BE
MINIMAL BROKEN BANDS...PRODUCING NO MORE THAN A DUSTING TO AN INCH
OF SNOW ACROSS MAINLY THE CENTRAL MOHAWK VALLEY MONDAY NIGHT.
MAINLY DRY ELSEWHERE...BUT TURNING QUITE A BIT COLDER...WITH LOWS
BACK INTO THE 20S FROM THE ALBANY SOUTHWARD...TEENS NORTH AND WEST
AND EVEN SINGLE NUMBERS ACROSS THE ADIRONDACK PARK.
TUESDAY...ANOTHER MID LEVEL TROUGH WILL WORK THROUGH THE REGION
INDUCING BROAD ASCENT. IT LOOKS TO HAVE LIMITED MOISTURE SO FOR
NOW...ONLY WENT WITH SLIGHT CHANCES OF SNOW SHOWERS EVERYWHERE ON
TUESDAY. WE WILL HAVE TO WATCH IF LATER RUNS DEVELOP A MORE
SIGNIFICANT SURFACE LOW PRESSURE WITH THIS TROUGH BUT IT WAS NOT
THERE ON THIS SET OF GUIDANCE. IT WILL BE EASILY COLD ENOUGH FOR ANY
PRECIPITATION TO FALL AS FALL ON TUESDAY WITH HIGHS ONLY IN THE
TEENS ACROSS OUR NORTHWEST ZONES...20S CENTRAL AREAS (UPPER 20S
CAPITAL REGION) AND LOWER 30S SOUTH ACROSS THE MID HUDSON VALLEY AND
LITCHFIELD COUNTY.
CHRISTMAS EVE...HIGH PRESSURE WILL BUILD INTO THE REGION AND IT
LOOKS DRY BUT COLD RIGHT INTO CHRISTMAS DAY. OVERNIGHT LOWS WILL
TUMBLE TO BELOW ZERO AS LOW AS -10 ACROSS THE ADIRONDACK
PARK...SINGLE NUMBERS THE REMAINDER OF NORTHERN ZONES (INCLUDING
SOUTHERN VERMONT)...10-15 ALBANY SOUTHWARD.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
THE EXTENDED PERIOD CONTINUES TO LOOK MAINLY DRY...WITH THE ONLY
CHANCE FOR MEASURABLE PRECIPITATION BEING IN THE FORM OF LAKE EFFECT
SNOW SHOWERS IN PORTIONS OF THE WESTERN ADIRONDACKS...FROM THURSDAY
NIGHT THROUGH FRIDAY NIGHT. A WEAK CLIPPER-LIKE LOW TRACKING FROM
THE NORTHERN LAKES TO THE CANADIAN MARITIMES WILL BE OF LITTLE MORE
CONSEQUENCE THAN PROVIDING EXTRA CLOUDINESS. ANOTHER SUCH LOW IS
EXPECTED TO PASS TO OUR NORTH LATE SUNDAY...ALSO PROVIDING LITTLE IN
THE WAY OF PRECIPITATION.
TEMPERATURES THURSDAY WILL RANGE FROM ABOUT THE UPPER 20S IN THE
ADIRONDACKS...TO THE UPPER 30S DOWN THE MID HUDSON VALLEY. HIGHS
WILL BE ABOUT 3 TO 8 DEGREES LOWER ON FRIDAY...AND WILL HOLD AROUND
THESE VALUES FOR SATURDAY. SUNDAY WILL BE MILDEST...WITH HIGHS FROM
AROUND 30 DEGREES IN THE ADIRONDACKS...TO AROUND 40 IN THE MID
HUDSON VALLEY. LOW TEMPERATURES WILL BE MAINLY FROM THE MID TEENS
TO MID 20S THROUGH THE PERIOD. NORMAL HIGHS FOR ALBANY ARE AROUND
FREEZING...AND NORMAL LOWS ARE IN THE UPPER TEENS.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
FLYING CONDITIONS VARYING QUITE A BIT ACROSS THE AREA...WITH KGFL
SOCKED IN WITH LIFR FOG AND LOW STRATUS ON THE COLD SIDE OF A
FRONTAL BOUNDARY...WHILE KPOU/KPSF ARE SOUTH OF THIS FRONT WITH
VFR CONDITIONS. KALB IS RIGHT ON THE BORDER NEAR THE BOUNDARY...AND
HAS SEEN VFR CONDITIONS DROP TO MVFR. ALL SITES ARE SEEING LIGHT
TO CALM WINDS AND THIS LOOKS TO CONTINUE THROUGH THE OVERNIGHT
HOURS.
A WAVE OF LOW PRESSURE WILL LIFT NORTHEASTWARD ALONG THE FRONTAL
BOUNDARY WHICH WILL RESULT IN ANOTHER ROUND OF LIGHT STEADY RAINFALL
STARTING BETWEEN 08Z-10Z. CONDITIONS ARE EXPECTED TO LOWER TO IFR
BEFORE 12Z AT ALL TERMINALS. WILL CONTINUE TO MENTION IFR
CONDITIONS THROUGH AROUND 18Z OR 19Z...WITH RAIN THEN ENDING AND
DRIER AIR STARTING TO WORK THEREAFTER WITH IMPROVING CONDITIONS.
ALL SITES LOOK TO BE VFR BY THE EVENING HOURS...WITH A WESTERLY
BREEZE DEVELOPING. A FEW GUSTS TOWARDS 20 KTS WILL BE POSSIBLE FOR
KALB/KPSF FOR MONDAY EVENING.
OUTLOOK...
MONDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA...SHSN.
TUESDAY: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHSN.
TUESDAY NIGHT TO FRIDAY: NO OPERATIONAL IMPACT. NO SIG WX.
&&
.HYDROLOGY...
WE CANCELLED THE FLOOD WATCH AS THE RAIN DID NOT MATERIALIZE. THE
SNOW MELT DID PRODUCE SOME SIGNIFICANT WITHIN BANKS RISE ON SOME
RIVERS. UTICA DID REACH MINOR FLOOD BUT THAT WAS PARTIALLY DUE TO ON
GOING CONSTRUCTION TO THE CANAL AS WELL AS RUNOFF FROM SNOWMELT.
ANY SHOWER ACTIVITY TONIGHT LOOKS LIGHT AND SPOTTY...UNDER A QUARTER
OF AN INCH WITH VIRTUALLY NO ADDITIONAL IMPACT EXPECTED. EVEN THOUGH
VERY MILD TEMPERATURES WILL OCCUR TONIGHT SOUTH OF THE CAPITAL
DISTRICT...THERE WILL BE VERY LITTLE SNOW TO MELT. FURTHER
NORTH...WHERE THERE IS SNOW...TEMPERATURES WILL NOT BE AS WARM AND
THEREFORE ANY SNOWMELT WILL BE MINIMAL.
ANOTHER ROUND OF RAINFALL IS LIKELY ACROSS THE SOUTHEAST HALF OF
THE AREA ON MONDAY...WITH AMOUNTS RANGING FROM A QUARTER TO THREE
QUARTERS OF AN INCH. THIS RAIN MIGHT CAUSE ADDITIONAL WITHIN
BANKFULL RISES BUT NO FLOODING IS EXPECTED AS THE SNOW IN THIS
AREA IS MOSTLY GONE.
COLDER DRIER AIR WILL FILTER BACK INTO THE REGION MONDAY NIGHT INTO
TUESDAY. ANY ADDITIONAL PRECIPITATION AT THIS POINT WOULD BE
SWITCHING TO SNOW...BUT LIGHT AND SPOTTY WITH NO IMPACTS ON RIVERS
AND STREAMS. THE COLDER TEMPERATURES WILL ALSO SLOW DOWN ANY
LEFTOVER RUNOFF.
DRY AND COLD WEATHER EXPECTED THROUGH THE REST OF THE WEEK.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...HWJIV
NEAR TERM...FRUGIS/HWJIV/JPV
SHORT TERM...HWJIV
LONG TERM...ELH
AVIATION...FRUGIS/JPV
HYDROLOGY...HWJIV/JPV
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
319 AM CST MON DEC 23 2013
.DISCUSSION...
745 PM CST
MINOR CHANGES MADE TO THE TONIGHT/S FORECAST....FOR FLURRIES/LIGHT
SNOW TRENDS THIS EVENING AND TO OVERNIGHT LOWS.
THE LATEST SHORT WAVE TROUGH TO AFFECT THE AREA WAS OVER SW WI
AND NE IA EARLY THIS EVENING AND IS PROGGED TO MOVE ACROSS THE
LOCAL AREA DURING THE LATER EVENING AND FIRST PART OF THE
OVERNIGHT HOURS. THIS DISTURBANCE HAS BEEN PRODUCING LIGHT SNOW
AND FLURRIES WHICH HAVE SPREAD FROM N CENTRAL TO NE IL OVER THE
LAST FEW HRS. VISIBILITY HAD BEEN REDUCED TO 2 1/2 TO 4 MI
OVER PORTIONS OF SOUTHERN WI BUT MINIMAL IF ANY REDUCTION IN
VISIBILITY REPORTED S OF THE STATE LINE. FLURRIES ARE EXPECTED
ACROSS MUCH OF THE FORECAST AREA THIS EVENING WHILE THE POTENTIAL
FOR LIGHT SNOW OF ANY CONSEQUENCE N OF I-80 AND INCREASING AS ONE
GETS CLOSER TO THE WI STATE LINE. EVEN THEN AMOUNTS OF NEW
SNOWFALL WILL BE A 1/2 INCH OR LESS...GENERALLY ONLY A TENTH OR
TWO.
REGARDING OVERNIGHT LOWS...AT 01Z TEMPERATURES QUICKLY DROPPED
OFF FROM AROUND 20 ALONG THE MS RIVER TO SINGLE DIGITS IN N
CENTRAL IA AND SW MN. SOME OF THIS IS DUE TO CLEARING OF THE
LOWER CLOUDS FROM OVER PARTS OF THAT AREA BUT EVEN DURING THE
AFTERNOON TEMPERATURES WERE ONLY IN THE 7 TO 14 DEG RANGE. LATEST
PROGS OF SFC...BL AND OTHER LOW LEVEL TEMPS SHOW THIS COLD AIR
ADVECTING E SLIGHTLY DEEPER OVER THE W PORTION OF THE FORECAST
AREA BY SUNRISE. THUS...HAVE SHAVED MAYBE A DEG OR SO OFF OF
LOWS ACROSS THE FAR WESTERN COUNTIES.
//PREV DISCUSSION...
326 PM CST
AS THE LATEST BOUT OF WINTER WEATHER WINDS DOWN...THE MAIN FOCUS FOR
THE NEXT SEVERAL DAYS WILL BE THE TEMPERATURE TRENDS.
HOWEVER...FOR THE REMAINDER OF THE AFTERNOON AND THROUGH THE
OVERNIGHT HOURS...THE CHANCES FOR PCPN ARE NOT TOTALLY OVER. THIS
AFTERNOON...A MID LEVEL DRY SLOT HAS CAPPED THE DEEP LAYER MOISTURE
FROM THE TOP WHILE COLD...DRY ADVECTION HAS DECREASED MOISTURE AT
THE SURFACE. THIS HAS LEFT A SHALLOW ZONE OF SATURATION THAT WILL
NOT BE DEEP ENOUGH INTO THE COLD AIR ALOFT TO GENERATE ANY ICE
PRODUCTION...LIMITING THE PCPN POTENTIAL TO DRIZZLE. AT THE
SURFACE...THE DRY ADVECTION HAS DECREASED DEWPOINTS ENOUGH THAT ANY
DRIZZLE THAT FALLS FROM THE SHALLOW CLOUD DECK WILL NOT REACH THE
GROUND. SO...WITH TEMPERATURES DROPPING BELOW FREEZING THROUGH THE
AFTERNOON WITH THE PERSISTENT COLD ADVECTION AT THE SURFACE...THE
POTENTIAL FOR ANY FREEZING DRIZZLE IS MINIMAL. THE OTHER OF
ADDITIONAL PCPN WILL COME THIS EVENING AND OVERNIGHT AS A NRN STREAM
SHORTWAVE DROPPING OUT OF THE NORTHERN PLAINS REINFORCES A SECONDARY
COLD FRONT DROPPING SOUTH THROUGH WISCONSIN. WITH DEEP LAYER
MOISTURE ON A DECREASING TREND AS THE STRONG SOUTHERN STREAM SYSTEM
MOVES OFF TO THE EAST...THE ENHANCED DYNAMICS FROM THE SHORTWAVE AND
SFC CONVERGENCE FROM THE COLD FRONT WILL ONLY BE SUFFICIENT TO
GENERATE A LITTLE LIGHT SNOW...WITH MINOR ADDITIONAL
ACCUMULATIONS...GENERALLY AROUND A COUPLE TENTHS OF AN INCH...
ESPECIALLY FOR THE NORTHERN PORTIONS OF THE CWA. THE SOUTHERN
PORTIONS OF THE CWA SHOULD SEE LITTLE OR NO ACCUMULATION. THROUGH
THE DAY TOMORROW...THE MAIN LONGWAVE UPPER TROUGH WILL MOVE THROUGH
THE MIDWEST AND WESTERN GREAT LAKES REGIONS...KEEPING A CHANCE FOR
SOME FLURRIES POSSIBLE THROUGH MUCH OF THE DAY TOMORROW. AS THE
UPPER TROUGH MOVES ACROSS THE AREA...COLD ARCTIC HIGH PRESSURE WILL
BUILD ACROSS THE NORTHERN PLAINS AND INTO THE MIDDLE MISSISSIPPI
VALLEY. THIS WILL BE THE FIRST IN A SERIES OF ARCTIC AIR INTRUSIONS
INTO THE REGION. BY MONDAY MORNING...TEMPERATURES SHOULD DROP INTO
THE SINGLE DIGITS WEST OF THE I-39 CORRIDOR WITH THE SLIGHTLY WARMER
AIR HANGING IN TO THE EAST. UNDER A PERSISTENT FETCH OF ARCTIC
AIR...THERE WILL BE LITTLE DIURNAL WARMING THROUGH THE DAY ON MONDAY
WITH HIGHS TOPPING OUT AT 10-15F WEST OF THE FOX VALLEY AND I-55
CORRIDOR WHILE TO THE EAST...TEMPERATURES REMAIN STEADY THROUGH THE
DAY IN THE LOW 20S.
INTO TUESDAY MORNING...AS SFC HIGH PRESSURE BUILDS ACROSS THE
MISSISSIPPI VALLEY WITH THE CENTER OF THE HIGH MOVING THROUGH
SOUTHERN IL...TEMPERATURES WILL DROP BELOW ZERO ALONG AND WEST OF A
WAUKEGAN TO PONTIAC LINE...INCLUDING THE ROCKFORD METRO AREA...WHILE
TEMPS TO THE EAST OF THIS LINE WILL DROP INTO THE LOWER SINGLE
DIGITS...INCLUDING THE CHICAGO METRO AREA. WEST WINDS OF 5 TO 10
MPH WILL BE SUFFICIENT TO CAUSE DANGEROUSLY COLD WIND CHILL READING
WITH THE ROCKFORD TO PONTIAC AREA POSSIBLE REACHING WIND CHILL
ADVISORY LEVELS OF -20F TO -25F. THE REST OF TUESDAY WILL REMAIN
QUITE COLD FOR LAST MINUTE CHRISTMAS SHOPPING AS HIGHS WILL RANGE
FROM THE SINGLE DIGITS OVER THE ROCKFORD AREA TO THE LOWER TO MIDDLE
TEENS OVER THE CHICAGO METRO AREA AND NORTHWESTERN INDIANA.
FOR THE NEXT SEVERAL DAYS...THE LONG WAVE UPPER LEVEL PATTERN WILL
REMAIN VERY HIGH AMPLITUDE AND PROGRESSIVE. THIS PATTERN WILL LEAD
TO RAPIDLY SWINGING PERIODS OF RELATIVE WARMING AND DRASTIC
COOLING. FOR CHRISTMAS EVEN INTO CHRISTMAS DAY...A STRONG SHORTWAVE
DROPPING OUT OF THE NORTHERN PLAINS WILL BRING ANOTHER CHANCE FOR
SOME LIGHT SNOW TO THE REGION. THIS WILL BE THE FIRST IN A SERIES
OF CLIPPER-TYPE SYSTEMS SOURCED FROM THE ARCTIC REGION. THESE
CLIPPER TYPE SYSTEMS...INCLUDING THE ONE EXPECTED TO IMPACT THE
REGION FOR CHRISTMAS EVE AND THROUGH CHRISTMAS DAY TYPICALLY HAVE
LITTLE DEEP LAYER MOISTURE TO WORK WITH AND THUS RELY ON UPPER
DYNAMICS TO GENERATE SNOWFALL. THIS SYSTEM WILL BE A FAIRLY TYPICAL
CLIPPER AND THE REGION COULD BRING PERHAPS 1 TO 2 INCHES.
FOLLOWING A PERIOD OF RELATIVE "WARMTH" ON WEDNESDAY WITH HIGHS IN
THE MIDDLE TO UPPER 20S OVER THE NORTHERN PORTIONS OF THE CWA TO THE
LOW 30S OVER THE SOUTHERN LOCATIONS...ANOTHER SHOT OF ARCTIC AIR
WILL MOVE IN WEDNESDAY NIGHT THROUGH FRIDAY. THE COLDEST PERIOD
WILL BE FRIDAY MORNING WHEN...ONCE AGAIN...THE NORTHWESTERN HALF OF
THE CWA WILL SEE TEMPERATURES DROP TO -5F TO -10F...WHILE THE SERN
PORTION OF THE CWA ONLY DROPS TO THE LOWER SINGLE DIGITS. THE
MODELS HAVE BEEN VERY CONSISTENT WITH THE PATTERN THROUGH THE WEEK
AND THE HIGH PRESSURE CENTER ASSOCIATED WITH THIS ARCTIC AIRMASS
WILL MOVE THROUGH SRN WISCONSIN AND NORTHERN ILLINOIS. SO...WHILE
AIR TEMPERATURES WILL BE SIMILAR TO THOSE SEEN ON TUESDAY
MORNING...WIND CHILLS WILL NOT BE QUITE AS LOW AS WINDS SHOULD NOT
BE QUITE AS STRONG. HOWEVER...THERE IS STILL SOME BUST POTENTIAL
FOR MIN TEMPS FRIDAY MORNING IF WINDS GO CALM RATHER THAN REMAINING
AROUND 5MPH. THE LIGHT WIND WOULD BE JUST ENOUGH TO TO KEEP THE SFC
STIRRED UP...LIMITING COOLING. ON THE OTHER HAND...IF THE SFC WINDS
CAN MANAGE TO GO CALM...AND SKIES CLEAR OUT ENOUGH...ENHANCED
RADIATIONAL COOLING AIDED BY SOME RESIDUAL SNOW COVER COULD ALLOW
TEMPERATURES TO DROP EVEN LOWER THAN CURRENTLY ANTICIPATED.
FOR THE WEEKEND AND INTO EARLY NEXT WEEK...WITH THE PATTERN
REMAINING QUICKLY PROGRESSIVE...TEMPERATURES FOR THE WEEKEND SHOULD
REBOUND BACK CLOSER TO SEASONAL NORMAL LEVELS. HIGHS SHOULD BE IN
THE UPPER 20S TO LOWER 30S. THE LONG RANGE MODEL GUIDANCE IS
INDICATING THE CHANCE FOR ANOTHER SHOT OF ARCTIC AIR WITH SUB-ZERO
TEMPERATES BY MONDAY MORNING. THE LONG RANGE FORECAST PERIOD SHOULD
BE DRY WITH THE NEXT CHANCE FOR ANY PCPN COMING EARLY NEXT WEEK AS
THE NEXT CLIPPER MOVES THROUGH THE AREA.
KREIN
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 09Z...
* VARIABLE MVFR CIGS THROUGH THE MORNING WITH SOME BREAKS TO VFR
POSSIBLE AT TIMES. VFR SCATTERING/CLEARING MAY RETURN BY
MIDDAY...WITH MVFR RETURNING LATER IN THE AFTERNOON.
* LIGHT SNOW WITH BRIEF MVFR VSBY DEPARTING NEXT HOUR OR SO
LEAVING FLURRIES BEHIND.
* LIGHT SNOW/FLURRIES RETURN LATER THIS AFTERNOON AND THIS
EVENING.
MDB
//DISCUSSION...UPDATED 09Z...
BAND OF LIGHT SNOW WITH SOME MVFR VSBY CONTINUES TO WORK EAST
ACROSS THE CHI METRO TERMINALS INTO NW INDIANA. EXPECT THIS TO
CLEAR THE AREA IN THE NEXT FEW HOURS LEAVING SOME FLURRIES BEHIND.
VARIABLE MVFR CIGS...WITH SOME BREAKS TO VFR STILL SCATTERED
ABOUT...WILL CONTINUE THROUGH MUCH OF THE MORNING BUT AM WATCHING
THE EASTWARD ADVANCEMENT OF CLEARING TOWARD THE MISSISSIPPI RIVER.
THIS MAY BE ABLE TO WORK INTO THE TERMINALS LATE THIS MORNING SO
MAY NEED TO SCATTER CLOUDS OUT BY MIDDAY. DO EXPECT MVFR TO RETURN
LATER THIS AFTERNOON AS LIGHT SNOW CHANCES INCREASE.
MDB
FROM 06Z...
AN UPPER TROUGH MOVING ACROSS THE AREA CONTINUES TO GENERATE SOME
LIGHT SNOW ACROSS THE TERMINALS WHICH WILL BE EXITING IN THE NEXT
FEW HOURS. CIGS ARE QUITE VARIABLE BUT MAINLY MVFR THOUGH THERE IS
AN AREA OF VFR CIGS FROM THE CHICAGO METRO EASTWARD OVER LAKE
MICHIGAN INTO THE GYY AREA. THIS LOOKS TO BE SHORT LIVED WITH MORE
MVFR UPSTREAM WORKING ITS WAY TOWARD THIS AREA OF IMPROVEMENT.
EXPECT VARIABLE MVFR CIGS THROUGH THIS AFTERNOON AND PROBABLY THE
UPCOMING EVENING AS WELL. CANNOT RULE OUT ADDITIONAL VFR BREAKS
THROUGH THE DAY THOUGH. ANOTHER TROUGH WILL BRING LIGHT SNOW AND
FLURRIES TO THE TERMINALS THIS AFTERNOON INTO THIS EVENING. THIS
LOOKS TO BE LIGHT OVERALL BUT SOME MINIMAL VSBY REDUCTION IS
POSSIBLE AT TIMES SO WILL NEED TO MONITOR INTENSITY TRENDS LATER
TODAY. WINDS WILL REMAIN WESTERLY THROUGH THE PERIOD WITH PERIODIC
15 TO 20 KT GUSTS DEVELOPING LATER THIS MORNING.
MDB
//ORD AND MDW CONFIDENCE...UPDATED 09Z...
* HIGH CONFIDENCE IN VARIABLE MVFR CIGS THROUGH THE
MORNING...MEDIUM CONFIDENCE IN VFR SCATTERING POTENTIAL TOWARD
MIDDAY. MEDIUM CONFIDENCE IN MVFR RETURNING LATER THIS
AFTERNOON.
* HIGH CONFIDENCE IN VSBY REDUCING LIGHT SNOW DEPARTING NEXT HOUR
OR SO WITH FLURRIES CONTINUING.
* MEDIUM CONFIDENCE IN ADDITIONAL LIGHT SNOW/FLURRIES LATER THIS
AFTERNOON WITH LOW CONFIDENCE IN CIG/VSBY IMPACTS.
MDB
//OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z...
TUESDAY...VFR DURING THE DAY. CHANCE OF LIGHT SNOW LATER TUESDAY
NIGHT WITH MVFR/IFR POSSIBLE.
WEDNESDAY...CHANCE OF LIGHT SNOW EARLY. MVFR/IFR POSSIBLE.
THURSDAY...VFR.
FRIDAY...VFR.
SATURDAY...VFR.
RATZER
&&
.MARINE...
302 AM CST
THE MAIN PERIOD OF CONCERN REMAINS THE TUESDAY NIGHT-WEDNESDAY
TIME FRAME WITH THE POTENTIAL FOR GALES CONTINUING. LOW PRESSURE
IS MOVING EASTWARD ACROSS NEW ENGLAND AND WILL MOVE OFFSHORE LATER
ON TODAY. STRONG HIGH PRESSURE IS MOVING SOUTHWARD INTO THE
DAKOTAS AND WILL REACH THE LOWER OHIO VALLEY BY TUESDAY
AFTERNOON...WITH A RIDGE AXIS EXTENDING NORTHWARD ACROSS LAKE
MICHIGAN AT THAT TIME. NORTHERLY WINDS ACROSS NORTHERN SECTIONS OF
THE LAKE TURN WESTERLY ACROSS THE SOUTHERN PART OF THE LAKE...WITH
STRONGER SPEEDS ACROSS THE FAR SOUTHERN QUARTER OR SO OF THE LAKE.
THIS IS DUE TO A LINGERING FAIRLY STRONG PRESSURE GRADIENT WHICH
WILL GRADUALLY WORK AWAY FROM THE AREA TONIGHT. WILL NEED TO KEEP
AN EYE ON WINDS ACROSS THE INDIANA NEARSHORE WATERS AS THEY MAY BE
CLOSE TO SMALL CRAFT ADVISORY CRITERIA BUT RIGHT NOW EXPECT THEM
TO REMAIN JUST BELOW. ONCE THE RIDGE CRESTS THE LAKE TUESDAY
AFTERNOON WINDS WILL QUICKLY TURN SOUTHERLY AND INCREASE IN SPEED
AS A LOW PRESSURE TROUGH WORKS IN FROM THE WEST. WITH A COLD
ATMOSPHERE IN PLACE UNSTABLE CONDITIONS WILL CONTINUE ACROSS THE
LAKE DESPITE WARM ADVECTION ALOFT AS THE PRESSURE GRADIENT BETWEEN
THE TWO SYSTEMS STRENGTHENS. THE SIGNAL FOR GALES REMAINS
CONSISTENT ACROSS MUCH OF THE LAKE FROM TUESDAY EVENING THROUGH
MID OR LATE WEDNESDAY MORNING. THE STRONGEST SPEEDS WILL BE
CENTRAL AND NORTH AND COULD SEE SOME GUSTS OVER 40 KT BASED ON
CURRENT INDICATIONS. WILL GO AHEAD AND BUMP WINDS TO 40 KT ACROSS
THE CENTRAL AND NORTHERN PARTS OF THE LAKE DURING THIS TIME. WILL
ALSO GO AHEAD AND ISSUE A GALE WATCH FOR THIS TIME AS WELL GIVEN
THAT THE SIGNAL HAS BEEN CONSISTENT FOR SEVERAL DAYS NOW. WILL
LEAVE THE NEARSHORE WATERS OUT OF THE WATCH FOR NOW WITH SOME
UNCERTAINTY IN GALES REACHING THAT FAR SOUTH AND A MAINLY OFFSHORE
COMPONENT...BUT WINDS MAY BE DUE SOUTH FOR A TIME TUESDAY EVENING
BRINGING GALES TO THE ILLINOIS WATERS THANKS TO THE MORE SHORE
PARALLEL DIRECTION. WINDS WILL TURN SOUTHWEST THEN WEST STARTING
WEDNESDAY MORNING WITH SPEEDS EASING UP AS THE PRESSURE GRADIENT
SLACKENS. HIGH PRESSURE WILL BUILD BACK ACROSS THE LAKE THURSDAY
BUT QUICKLY DEPART TO THE EAST WITH SEVERAL LOW PRESSURE SYSTEMS
CROSSING THE REGION FRIDAY AND SATURDAY. THESE WILL ALLOW WINDS TO
FLUCTUATE BETWEEN NORTHWEST AND SOUTHWEST AS THEY PASS AS WELL AS
ALLOW SPEEDS TO INCREASE. A LITTLE EARLY FOR DETAILS BUT IT DOES
APPEAR THAT A BETTER ORGANIZED LOW WILL PASS TO THE NORTH SOME
TIME SATURDAY WITH ANOTHER STRONG HIGH BUILDING IN BEHIND IT. THIS
WOULD HAVE THE BEST POTENTIAL TO BRING A PERIOD OF GALES AT SOME
POINT SATURDAY INTO SUNDAY...WITH PERHAPS THE BETTER POTENTIAL
EARLY SUNDAY AS THE LOW PASSES AND THE HIGH APPROACHES.
MDB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WATCH...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...9 PM TUESDAY TO NOON
WEDNESDAY.
&&
$$
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[top]
Area Forecast Discussion
National Weather Service Lincoln IL
245 AM CST Mon Dec 23 2013
.DISCUSSION...
ISSUED 245 AM CST Mon Dec 23 2013
SHORT TERM...Today through Wednesday
Ridge of high pressure currently over the Plains will build
eastward today, allowing skies to partially clear across central
Illinois. 08z/2am IR satellite imagery shows back edge of low
clouds along a Galesburg to Quincy line, with timing tools taking
the clearing line to near the I-55 corridor by mid-morning. After
a period of mostly sunny skies across the western KILX CWA this
morning, think diurnal clouds will re-develop thanks to cyclonic
flow aloft. End result will be partly sunny skies west and mostly
cloudy conditions further east toward the Indiana border. Given
strong CAA, temps will struggle to rise much from early morning
lows, with afternoon highs ranging from the teens along/west of
I-55 to around 30 degrees south of I-70.
Skies will clear out completely tonight, setting up one of the
coldest nights of the winter season thus far. Overnight lows will
drop into the single digits across the board, with readings
dipping below zero in the Illinois River Valley. Coldest temps of
around -8F will be found in the far NW CWA around Galesburg where
4 inches of snow remain on the ground. W/NW winds of 10 to 15 mph
in the evening will subside to less than 10 mph overnight,
producing bitterly cold wind-chill values. Will be issuing a Wind
Chill Advisory for locations along and north of a Rushville to
Bloomington-Normal line, where wind-chills will plunge into the
-15 to -20F range tonight into Tuesday morning.
After a very cold day on Tuesday with highs only in the teens and
20s, winds will switch to southerly and temps will warm
considerably ahead of an approaching clipper system Tuesday night
into Wednesday. Models agree that system is a bit faster than
previously forecast, but still disagree on how far south to spread
QPF. Prefer the NAM model, which brings light snow across much of
central Illinois late Tuesday night into Wednesday morning.
Greatest chance for measurable snow still looks to be focused
from the Peoria area northward, where likely POPs are in order.
Snow chances decrease further south, with only slight chance POPs
along/south of I-70. Even though system will be fast-moving and
will depart the area around midday Wednesday, think around one
half inch of snow will be possible across the far northern CWA by
Wednesday morning. Any new snow that falls will likely not stick
around for long though, as high temps reach the 30s on Wednesday.
LONG TERM...Thursday through Sunday
Yet another wave will dig southward Wednesday night, bringing a
few snow flurries to the area. Once this feature passes, another
chunk of very cold air will settle southward into central Illinois
by the end of the week, resulting in high temps only in the 20s on
Thursday and Friday. The temperature roller-coaster ride will
continue next weekend, as another fast-moving storm system
approaches from the northwest. Southerly winds ahead of this
feature will boost temps back into the 30s on Saturday, before
another shot of very cold air arrives early next week.
Barnes
&&
.AVIATION...
ISSUED 1110 PM CST Sun Dec 22 2013
Main forecast challenge will be with any appreciable clearing of
the MVFR cigs across the area towards morning. Latest satellite
data and surface obs showing the backedge of the cloud shield
was still over east central Iowa late this evening, and tracking
southeast at about 20 kts. This would put any clearing into
PIA and SPI between 10z and 12z and to the east of CMI by 15z.
Not very confident on that scenario, despite most models trending
in that direction. HRRR has been the quickest with the backedge
of the cloud shield progressing across our forecast area in the
06z-09z time frame, while the Nam-Wrf and local Wrf-ARW models
were a bit more conservative in the clearing trend from west to
east which we will go with during this forecast period. Still
appears the 10z-12z time frame looks ok for PIA and SPI but the
hi-res forecast soundings indicate the clouds will tend to slow
down their eastward progression tomorrow morning just east of
the I-55 corridor with additional stratocu clouds from the north
possibly affecting our PIA and BMI TAF sites tomorrow afternoon.
We should see any lingering MVFR/low VFR cigs dissipate by tomorrow
evening across the north as Arctic high pressure settles in bringing
in some very cold temperatures for tomorrow night.
Surface winds will remain out of the west to northwest at 10 to 15
kts tonight...with speeds of from 12 to 17 kts on Monday with a few
gusts at or above 20 kts at times tomorrow afternoon. Winds should
diminish to around 10 kts from the northwest tomorrow evening.
Smith
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1211 AM CST MON DEC 23 2013
.DISCUSSION...
745 PM CST
MINOR CHANGES MADE TO THE TONIGHT/S FORECAST....FOR FLURRIES/LIGHT
SNOW TRENDS THIS EVENING AND TO OVERNIGHT LOWS.
THE LATEST SHORT WAVE TROUGH TO AFFECT THE AREA WAS OVER SW WI
AND NE IA EARLY THIS EVENING AND IS PROGGED TO MOVE ACROSS THE
LOCAL AREA DURING THE LATER EVENING AND FIRST PART OF THE
OVERNIGHT HOURS. THIS DISTURBANCE HAS BEEN PRODUCING LIGHT SNOW
AND FLURRIES WHICH HAVE SPREAD FROM N CENTRAL TO NE IL OVER THE
LAST FEW HRS. VISIBILITY HAD BEEN REDUCED TO 2 1/2 TO 4 MI
OVER PORTIONS OF SOUTHERN WI BUT MINIMAL IF ANY REDUCTION IN
VISIBILITY REPORTED S OF THE STATE LINE. FLURRIES ARE EXPECTED
ACROSS MUCH OF THE FORECAST AREA THIS EVENING WHILE THE POTENTIAL
FOR LIGHT SNOW OF ANY CONSEQUENCE N OF I-80 AND INCREASING AS ONE
GETS CLOSER TO THE WI STATE LINE. EVEN THEN AMOUNTS OF NEW
SNOWFALL WILL BE A 1/2 INCH OR LESS...GENERALLY ONLY A TENTH OR
TWO.
REGARDING OVERNIGHT LOWS...AT 01Z TEMPERATURES QUICKLY DROPPED
OFF FROM AROUND 20 ALONG THE MS RIVER TO SINGLE DIGITS IN N
CENTRAL IA AND SW MN. SOME OF THIS IS DUE TO CLEARING OF THE
LOWER CLOUDS FROM OVER PARTS OF THAT AREA BUT EVEN DURING THE
AFTERNOON TEMPERATURES WERE ONLY IN THE 7 TO 14 DEG RANGE. LATEST
PROGS OF SFC...BL AND OTHER LOW LEVEL TEMPS SHOW THIS COLD AIR
ADVECTING E SLIGHTLY DEEPER OVER THE W PORTION OF THE FORECAST
AREA BY SUNRISE. THUS...HAVE SHAVED MAYBE A DEG OR SO OFF OF
LOWS ACROSS THE FAR WESTERN COUNTIES.
//PREV DISCUSSION...
326 PM CST
AS THE LATEST BOUT OF WINTER WEATHER WINDS DOWN...THE MAIN FOCUS FOR
THE NEXT SEVERAL DAYS WILL BE THE TEMPERATURE TRENDS.
HOWEVER...FOR THE REMAINDER OF THE AFTERNOON AND THROUGH THE
OVERNIGHT HOURS...THE CHANCES FOR PCPN ARE NOT TOTALLY OVER. THIS
AFTERNOON...A MID LEVEL DRY SLOT HAS CAPPED THE DEEP LAYER MOISTURE
FROM THE TOP WHILE COLD...DRY ADVECTION HAS DECREASED MOISTURE AT
THE SURFACE. THIS HAS LEFT A SHALLOW ZONE OF SATURATION THAT WILL
NOT BE DEEP ENOUGH INTO THE COLD AIR ALOFT TO GENERATE ANY ICE
PRODUCTION...LIMITING THE PCPN POTENTIAL TO DRIZZLE. AT THE
SURFACE...THE DRY ADVECTION HAS DECREASED DEWPOINTS ENOUGH THAT ANY
DRIZZLE THAT FALLS FROM THE SHALLOW CLOUD DECK WILL NOT REACH THE
GROUND. SO...WITH TEMPERATURES DROPPING BELOW FREEZING THROUGH THE
AFTERNOON WITH THE PERSISTENT COLD ADVECTION AT THE SURFACE...THE
POTENTIAL FOR ANY FREEZING DRIZZLE IS MINIMAL. THE OTHER OF
ADDITIONAL PCPN WILL COME THIS EVENING AND OVERNIGHT AS A NRN STREAM
SHORTWAVE DROPPING OUT OF THE NORTHERN PLAINS REINFORCES A SECONDARY
COLD FRONT DROPPING SOUTH THROUGH WISCONSIN. WITH DEEP LAYER
MOISTURE ON A DECREASING TREND AS THE STRONG SOUTHERN STREAM SYSTEM
MOVES OFF TO THE EAST...THE ENHANCED DYNAMICS FROM THE SHORTWAVE AND
SFC CONVERGENCE FROM THE COLD FRONT WILL ONLY BE SUFFICIENT TO
GENERATE A LITTLE LIGHT SNOW...WITH MINOR ADDITIONAL
ACCUMULATIONS...GENERALLY AROUND A COUPLE TENTHS OF AN INCH...
ESPECIALLY FOR THE NORTHERN PORTIONS OF THE CWA. THE SOUTHERN
PORTIONS OF THE CWA SHOULD SEE LITTLE OR NO ACCUMULATION. THROUGH
THE DAY TOMORROW...THE MAIN LONGWAVE UPPER TROUGH WILL MOVE THROUGH
THE MIDWEST AND WESTERN GREAT LAKES REGIONS...KEEPING A CHANCE FOR
SOME FLURRIES POSSIBLE THROUGH MUCH OF THE DAY TOMORROW. AS THE
UPPER TROUGH MOVES ACROSS THE AREA...COLD ARCTIC HIGH PRESSURE WILL
BUILD ACROSS THE NORTHERN PLAINS AND INTO THE MIDDLE MISSISSIPPI
VALLEY. THIS WILL BE THE FIRST IN A SERIES OF ARCTIC AIR INTRUSIONS
INTO THE REGION. BY MONDAY MORNING...TEMPERATURES SHOULD DROP INTO
THE SINGLE DIGITS WEST OF THE I-39 CORRIDOR WITH THE SLIGHTLY WARMER
AIR HANGING IN TO THE EAST. UNDER A PERSISTENT FETCH OF ARCTIC
AIR...THERE WILL BE LITTLE DIURNAL WARMING THROUGH THE DAY ON MONDAY
WITH HIGHS TOPPING OUT AT 10-15F WEST OF THE FOX VALLEY AND I-55
CORRIDOR WHILE TO THE EAST...TEMPERATURES REMAIN STEADY THROUGH THE
DAY IN THE LOW 20S.
INTO TUESDAY MORNING...AS SFC HIGH PRESSURE BUILDS ACROSS THE
MISSISSIPPI VALLEY WITH THE CENTER OF THE HIGH MOVING THROUGH
SOUTHERN IL...TEMPERATURES WILL DROP BELOW ZERO ALONG AND WEST OF A
WAUKEGAN TO PONTIAC LINE...INCLUDING THE ROCKFORD METRO AREA...WHILE
TEMPS TO THE EAST OF THIS LINE WILL DROP INTO THE LOWER SINGLE
DIGITS...INCLUDING THE CHICAGO METRO AREA. WEST WINDS OF 5 TO 10
MPH WILL BE SUFFICIENT TO CAUSE DANGEROUSLY COLD WIND CHILL READING
WITH THE ROCKFORD TO PONTIAC AREA POSSIBLE REACHING WIND CHILL
ADVISORY LEVELS OF -20F TO -25F. THE REST OF TUESDAY WILL REMAIN
QUITE COLD FOR LAST MINUTE CHRISTMAS SHOPPING AS HIGHS WILL RANGE
FROM THE SINGLE DIGITS OVER THE ROCKFORD AREA TO THE LOWER TO MIDDLE
TEENS OVER THE CHICAGO METRO AREA AND NORTHWESTERN INDIANA.
FOR THE NEXT SEVERAL DAYS...THE LONG WAVE UPPER LEVEL PATTERN WILL
REMAIN VERY HIGH AMPLITUDE AND PROGRESSIVE. THIS PATTERN WILL LEAD
TO RAPIDLY SWINGING PERIODS OF RELATIVE WARMING AND DRASTIC
COOLING. FOR CHRISTMAS EVEN INTO CHRISTMAS DAY...A STRONG SHORTWAVE
DROPPING OUT OF THE NORTHERN PLAINS WILL BRING ANOTHER CHANCE FOR
SOME LIGHT SNOW TO THE REGION. THIS WILL BE THE FIRST IN A SERIES
OF CLIPPER-TYPE SYSTEMS SOURCED FROM THE ARCTIC REGION. THESE
CLIPPER TYPE SYSTEMS...INCLUDING THE ONE EXPECTED TO IMPACT THE
REGION FOR CHRISTMAS EVE AND THROUGH CHRISTMAS DAY TYPICALLY HAVE
LITTLE DEEP LAYER MOISTURE TO WORK WITH AND THUS RELY ON UPPER
DYNAMICS TO GENERATE SNOWFALL. THIS SYSTEM WILL BE A FAIRLY TYPICAL
CLIPPER AND THE REGION COULD BRING PERHAPS 1 TO 2 INCHES.
FOLLOWING A PERIOD OF RELATIVE "WARMTH" ON WEDNESDAY WITH HIGHS IN
THE MIDDLE TO UPPER 20S OVER THE NORTHERN PORTIONS OF THE CWA TO THE
LOW 30S OVER THE SOUTHERN LOCATIONS...ANOTHER SHOT OF ARCTIC AIR
WILL MOVE IN WEDNESDAY NIGHT THROUGH FRIDAY. THE COLDEST PERIOD
WILL BE FRIDAY MORNING WHEN...ONCE AGAIN...THE NORTHWESTERN HALF OF
THE CWA WILL SEE TEMPERATURES DROP TO -5F TO -10F...WHILE THE SERN
PORTION OF THE CWA ONLY DROPS TO THE LOWER SINGLE DIGITS. THE
MODELS HAVE BEEN VERY CONSISTENT WITH THE PATTERN THROUGH THE WEEK
AND THE HIGH PRESSURE CENTER ASSOCIATED WITH THIS ARCTIC AIRMASS
WILL MOVE THROUGH SRN WISCONSIN AND NORTHERN ILLINOIS. SO...WHILE
AIR TEMPERATURES WILL BE SIMILAR TO THOSE SEEN ON TUESDAY
MORNING...WIND CHILLS WILL NOT BE QUITE AS LOW AS WINDS SHOULD NOT
BE QUITE AS STRONG. HOWEVER...THERE IS STILL SOME BUST POTENTIAL
FOR MIN TEMPS FRIDAY MORNING IF WINDS GO CALM RATHER THAN REMAINING
AROUND 5MPH. THE LIGHT WIND WOULD BE JUST ENOUGH TO TO KEEP THE SFC
STIRRED UP...LIMITING COOLING. ON THE OTHER HAND...IF THE SFC WINDS
CAN MANAGE TO GO CALM...AND SKIES CLEAR OUT ENOUGH...ENHANCED
RADIATIONAL COOLING AIDED BY SOME RESIDUAL SNOW COVER COULD ALLOW
TEMPERATURES TO DROP EVEN LOWER THAN CURRENTLY ANTICIPATED.
FOR THE WEEKEND AND INTO EARLY NEXT WEEK...WITH THE PATTERN
REMAINING QUICKLY PROGRESSIVE...TEMPERATURES FOR THE WEEKEND SHOULD
REBOUND BACK CLOSER TO SEASONAL NORMAL LEVELS. HIGHS SHOULD BE IN
THE UPPER 20S TO LOWER 30S. THE LONG RANGE MODEL GUIDANCE IS
INDICATING THE CHANCE FOR ANOTHER SHOT OF ARCTIC AIR WITH SUB-ZERO
TEMPERATES BY MONDAY MORNING. THE LONG RANGE FORECAST PERIOD SHOULD
BE DRY WITH THE NEXT CHANCE FOR ANY PCPN COMING EARLY NEXT WEEK AS
THE NEXT CLIPPER MOVES THROUGH THE AREA.
KREIN
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* MVFR CIGS EXPECTED TO PREVAIL WITH TEMPORARY BREAKS TO VFR NEXT
1-2 HRS.
* LIGHT SNOW/FLURRIES RETURN LATER THIS AFTERNOON AND THIS
EVENING.
MDB
//DISCUSSION...UPDATED 06Z...
AN UPPER TROUGH MOVING ACROSS THE AREA CONTINUES TO GENERATE SOME
LIGHT SNOW ACROSS THE TERMINALS WHICH WILL BE EXITING IN THE NEXT
FEW HOURS. CIGS ARE QUITE VARIABLE BUT MAINLY MVFR THOUGH THERE IS
AN AREA OF VFR CIGS FROM THE CHICAGO METRO EASTWARD OVER LAKE
MICHIGAN INTO THE GYY AREA. THIS LOOKS TO BE SHORT LIVED WITH MORE
MVFR UPSTREAM WORKING ITS WAY TOWARD THIS AREA OF IMPROVEMENT.
EXPECT VARIABLE MVFR CIGS THROUGH THIS AFTERNOON AND PROBABLY THE
UPCOMING EVENING AS WELL. CANNOT RULE OUT ADDITIONAL VFR BREAKS
THROUGH THE DAY THOUGH. ANOTHER TROUGH WILL BRING LIGHT SNOW AND
FLURRIES TO THE TERMINALS THIS AFTERNOON INTO THIS EVENING. THIS
LOOKS TO BE LIGHT OVERALL BUT SOME MINIMAL VSBY REDUCTION IS
POSSIBLE AT TIMES SO WILL NEED TO MONITOR INTENSITY TRENDS LATER
TODAY. WINDS WILL REMAIN WESTERLY THROUGH THE PERIOD WITH PERIODIC
15 TO 20 KT GUSTS DEVELOPING LATER THIS MORNING.
MDB
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* HIGH CONFIDENCE IN MAINLY MVFR CIGS THROUGH THE AFTERNOON WITH
TEMPORARY BREAKS TO VFR EARLY TONIGHT.
* MEDIUM CONFIDENCE IN LIGHT SNOW/FLURRY POTENTIAL LATER THIS
AFTERNOON AND THIS EVENING. LOW CONFIDENCE IN CIG/VSBY IMPACTS.
MDB
//OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z...
TUESDAY...VFR DURING THE DAY. CHANCE OF LIGHT SNOW LATER TUESDAY
NIGHT WITH MVFR/IFR POSSIBLE.
WEDNESDAY...CHANCE OF LIGHT SNOW EARLY. MVFR/IFR POSSIBLE.
THURSDAY...VFR.
FRIDAY...VFR.
SATURDAY...VFR.
RATZER
&&
.MARINE...
244 PM...AS LOW PRESSURE MOVES ACROSS NEW ENGLAND TONIGHT AND
MONDAY...A WEAKER TROUGH WILL EXTEND WEST ACROSS THE LAKES REGION
INCLUDING CENTRAL LAKE MICHIGAN THROUGH MONDAY AFTERNOON. THIS
WILL ALLOW FOR NORTHERLY WINDS ACROSS THE NORTH HALF OF THE
LAKE...WITH INCREASING WESTERLY WINDS ACROSS THE SOUTHERN THIRD OR
QUARTER OF THE LAKE TONIGHT. THESE WESTERLY WINDS COULD INCREASE
INTO THE 20-25KT RANGE MONDAY AFTERNOON INTO MONDAY EVENING AND
TRENDS WILL NEED TO BE MONITORED WITH LATER FORECASTS. THIS TROUGH
WILL DISSIPATE MONDAY EVENING AS A RIDGE OF HIGH PRESSURE MOVES
ACROSS THE LAKE TUESDAY...WITH THE CENTER OF THE HIGH REMAINING
ACROSS THE OHIO VALLEY. ON THE BACK SIDE OF THIS RIDGE...WINDS
WILL TURN SOUTHERLY TUESDAY AFTERNOON AND QUICKLY INCREASE TO 30
KTS TUESDAY EVENING...AS A LARGE TROUGH OF LOW PRESSURE MOVES
ACROSS THE MIDWEST AND WESTERN LAKES. CONFIDENCE REGARDING LOW END
GALES IS LOW AT THIS DISTANCE BUT HAVE OPTED TO INCLUDE THEM
ACROSS THE NORTH HALF. WINDS TURN WESTERLY AND DIMINISH WEDNESDAY
AFTERNOON INTO WEDNESDAY EVENING...AS THE TROUGH PASSES ACROSS
THE LAKE. ANOTHER HIGH WILL MOVE FROM THE NORTHERN PLAINS THURSDAY
TO ACROSS THE SOUTHERN LAKES REGION FRIDAY. ANOTHER LOW WILL
QUICKLY MOVE ACROSS THE NORTHERN LAKES FRIDAY NIGHT. THE GRADIENT
WILL TIGHTEN AHEAD OF THIS SYSTEM WITH A SHORT PERIOD OF GALES
POSSIBLE. CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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Area Forecast Discussion
National Weather Service Lincoln IL
1121 PM CST Sun Dec 22 2013
.DISCUSSION...
ISSUED 840 PM CST Sun Dec 22 2013
Storm system that brought the wintry weather to the region
yesterday continues to push well of to our east this evening.
Latest satellite and surface observations to our west indicate
a decrease in cloud cover over parts of east central Iowa which
was working its way east this evening. Latest RAP soundings not
very optimistic with respect to eroding the low level moisture
already in place so will continue to hold on to the cloud cover
overnight. Despite the cloud cover, low level cold advection
behind the storm system will drawn down some rather cold temps
by morning with overnight lows in the single digits in our
far northwest. Still seeing an occasional report of flurries
to our west over eastern Iowa and west central IL so will hold
on to the flurries for the overnight hours. Current zones are
in good shape, so other than the usual tweaks to the evening
hourly temperatures and winds, no significant enough changes
were made to warrant an evening update.
&&
.AVIATION...
ISSUED 1110 PM CST Sun Dec 22 2013
Main forecast challenge will be with any appreciable clearing of
the MVFR cigs across the area towards morning. Latest satellite
data and surface obs showing the backedge of the cloud shield
was still over east central Iowa late this evening, and tracking
southeast at about 20 kts. This would put any clearing into
PIA and SPI between 10z and 12z and to the east of CMI by 15z.
Not very confident on that scenario, despite most models trending
in that direction. HRRR has been the quickest with the backedge
of the cloud shield progressing across our forecast area in the
06z-09z time frame, while the Nam-Wrf and local Wrf-ARW models
were a bit more conservative in the clearing trend from west to
east which we will go with during this forecast period. Still
appears the 10z-12z time frame looks ok for PIA and SPI but the
hi-res forecast soundings indicate the clouds will tend to slow
down their eastward progression tomorrow morning just east of
the I-55 corridor with additional stratocu clouds from the north
possibly affecting our PIA and BMI TAF sites tomorrow afternoon.
We should see any lingering MVFR/low VFR cigs dissipate by tomorrow
evening across the north as Arctic high pressure settles in bringing
in some very cold temperatures for tomorrow night.
Surface winds will remain out of the west to northwest at 10 to 15
kts tonight...with speeds of from 12 to 17 kts on Monday with a few
gusts at or above 20 kts at times tomorrow afternoon. Winds should
diminish to around 10 kts from the northwest tomorrow evening.
Smith
&&
.PREV DISCUSSION...
ISSUED 300 PM CST Sun Dec 22 2013
The short and medium range models are all in very good agreement
that central and eastern IL will experience quite a range of
temperatures during the next week as a series of northwest
flow/clipper systems take aim at the upper Midwest. This type of
flow also indicates that no major storms are on the horizon for
the next several days either.
SHORT TERM...Tonight through Tuesday
Low level cyclonic flow from the storm system moving through the
eastern Great Lakes will keep clouds and scattered snow flurries over
the forecast area through tonight and into much of the day Monday.
There may be a few breaks in areas south of a Jacksonville-SPI-
DEC-Paris line Monday as surface ridging tries to nose into the
area, but overall clouds will prevail. The clouds will not do much
to keep us warmer since plenty of low level cold air upstream is
poised to move into the area. Lows tonight will be in the single
digits west of the Illinois River, with teens in central IL and
and 20s in the southeast. Continued cold advection Monday will
result in nearly steady temperatures or only very minor rises.
Arctic high pressure with a central pressure around 1040 mb will
drop into the mid MS Valley by daybreak Tuesday. This will give us
very cold temperatures, with sub-zero readings west of I-55 and
single digits in the rest of the forecast area. The gradient ahead
of the high pressure area will be moderately strong, with surface
winds 10-15 mph in the evening and around 10 mph overnight. The
resulting wind chill values will be below zero north of I-70 with
-10 to -17 north of I-72 later Monday evening into Tuesday morning.
May need a wind chill advisory in later forecasts if this trend
continues.
The cold temperatures will continue on Christmas Eve as the high
slowly moves across Illinois. However, a southerly flow is
expected to develop Tuesday night, once again resulting in very
little diurnal temperature swing. The next in a series of clipper
systems will track into the upper Midwest later on Christmas Eve.
The best lift with this system will be in WI and northern IL, but
there is a chance for a little light snow by Christmas morning -
mainly along the I-74 corridor.
LONG TERM...Christmas Day through Sunday
The cold front associated with the Christmas morning clipper will
be approaching from the northwest by evening. Again, the best
upper support will be to the north, so will keep the chances for
snow along and north of I-74. The rest of the area will be mostly
cloudy on Christmas Day with a few snow flurries at times. The
southerly winds ahead of the front will allow temperatures to
rebound into the 30s. However, this will be short lived after the
front moves through Wednesday night. Highs Thursday will mainly be
in the 20s, with lower to middle 30s in southeast IL. The coldest
air with the next Arctic high will push in Friday morning,
although at this time it does not appear that it will be as cold
as the previous Arctic airmass.
The upper level flow will back to more of a westerly/zonal flow by
the weekend as an upper trough from the Canadian Rockies digs
toward the southern Plains. The result for Illinois will be
warmer, more seasonal temperatures for Saturday and Sunday. The
GFS and European models are similar in indicating a cold front
approaching Sunday. However, with high pressure expected to be
parked over the southern states, moisture will be quite limited.
Will hold off on chance PoPs for now, and go with a dry forecast
since the higher probability appears to be toward the Great Lakes
area.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1140 PM EST SUN DEC 22 2013
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 245 PM EST SUN DEC 22 2013
AS THE MAJOR RAINMAKER CONTINUES TO MOVE QUICKLY AWAY FROM THE
AREA...UPPER LEVEL FLOW WILL REMAIN STRONGLY CYCLONIC AS HIGH
PRESSURE BUILDS INTO THE AREA. RESIDUAL LOW LEVEL MOISTURE AND
THIS CYCLONIC FLOW MAY BE ABLE TO SQUEEZE OUT A FEW FLURRIES AT
TIMES...BUT NOTHING OF SIGNIFICANCE.
&&
.NEAR TERM /OVERNIGHT/...
ISSUED AT 950 PM EST SUN DEC 22 2013
LOW STRATUS DECK REMAINS THIS EVENING ALONG WITH A FEW FLURRIES
AND POCKETS OF LIGHT DRIZZLE. TEMPS CONTINUE TO SLOWLY BUT
STEADILY FALL AS THE COLDER AIR SEEPS INTO THE REGION FROM THE
WEST. MOST LOCATIONS WERE IN THE LOWER AND MIDDLE 30S AS OF 0230Z.
ONLY SUBTLE ADJUSTMENTS NEEDED FOR THE EVENING UPDATE. EXPECT
CLOUDS TO LINGER ALL NIGHT WITH STRATUS DECK ALL THE WAY BACK TO
THE WEST OF THE MISSISSIPPI RIVER. FURTHERMORE...PRESENCE OF THE
SLOW MOVING FRONTAL BOUNDARY ACROSS THE APPALACHIANS IS DELAYING
EXPANSION OF HIGH PRESSURE EAST INTO THE OHIO VALLEY. DECIDED TO
EXTEND CHANCES FOR FLURRIES THROUGH THE NIGHT AS WEAK INSTABILITY
NOTED BENEATH THE INVERSION ON RAP SOUNDINGS AND FORCING ALOFT
PRESENT. POCKETS OF DRIZZLE REMAIN POSSIBLE OVER EASTERN COUNTIES
FOR THE DURATION OF THE EVENING BUT EXPECT A CHANGE TO FLURRIES IN
THESE AREAS AS THE BOUNDARY LAYER COOLS. OVERNIGHT LOWS IN THE
20S LOOK REASONABLE.
ZONE AND GRID UPDATES OUT.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
ISSUED AT 245 PM EST SUN DEC 22 2013
SURFACE HIGH PRESSURE WILL DOMINATE THE SHORT TERM
PERIOD...ALTHOUGH AN UPPER LEVEL TROUGH AXIS WILL SWING THROUGH
THE AREA TOMORROW NIGHT. WILL CARRY A SLIGHT CHANCE OF FLURRIES
LATE TOMORROW INTO TOMORROW NIGHT...BUT AGAIN NO MEASURABLE POP AS
MOISTURE IS LACKING TO SAY THE LEAST.
ON TEMPS...CONSENSUS NUMBERS LOOK VERY REASONABLE GIVEN EXPECTED
LOW LEVEL THICKNESSES. FEW TWEAKS WERE REQUIRED BUT GENERALLY
STUCK CLOSE TO THESE NUMBERS.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
ISSUED AT 240 PM EST SUN DEC 22 2013
NO MAJOR WEATHER CONCERNS FOR THE EXTENDED WHICH SHOULD ALLOW RIVER
FLOODING TO RUN ITS COURSE. THAT BEING SAID...MODELS IN GENERAL
AGREEMENT THAT TWO DIFFERENT SYSTEMS WILL BRING POTENTIAL FOR MINOR
PRECIPITATION WEDNESDAY NIGHT AND THURSDAY AS WELL AS SUNDAY.
SO...KEPT SMALL REGIONAL ALLBLEND POPS. IT SHOULD BE COLD ENOUGH FOR
ONLY SNOW AS PRECIPITATION TYPE WEDNESDAY NIGHT AND THURSDAY...BUT
SOUTHWEST FLOW AHEAD OF LATE WEEKEND FRONTAL SYSTEM SUGGESTS
POSSIBILITY EXISTS OF A MIX OF RAIN AND SNOW IF NOT JUST RAIN.
ALLBLEND TEMPERATURES LOOK REASONABLE WITH AFTERNOON TEMPERATURES
STARTING OFF IN THE 20S AND 30S AND THEN WARMING TO THE 30S AND 40S
BY SATURDAY.
&&
.AVIATION /DISCUSSION FOR THE 230600Z TAFS/...
ISSUED AT 1140 PM EST SUN DEC 22 2013
WIDESPREAD MVFR CEILINGS AROUND 012-015 CONTINUE ACROSS THE AREA AS
MOISTURE REMAINS TRAPPED BELOW AN INVERSION. SOME BRIEF PERIODS OF
IFR CEILINGS 008-009 AGL ALONG WITH SOME FLURRIES POSSIBLE FOR THE
REST OF THE NIGHT AS AN UPPER TROUGH MOVES THROUGH...BUT THESE
CONDITIONS SHOULD NOT BE TOO WIDESPREAD OR PROLONGED IN NATURE.
CLEARING LINE CURRENTLY OUT TOWARDS THE MISSISSIPPI RIVER...SO SO IT
MAY BE LATE MORNING OR MIDDAY MONDAY BEFORE THE LOWER CEILINGS
SCATTER OUT.
SURFACE WINDS GENERALLY AT OR BELOW 12 KTS THROUGH 231800Z.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...NIELD
NEAR TERM...RYAN
SHORT TERM...NIELD
LONG TERM...MK
AVIATION...JAS
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS GOODLAND KS
254 AM MST MON DEC 23 2013
.UPDATE...
ISSUED AT 630 PM MST SUN DEC 22 2013
AT 0130Z LIGHT SNOW WAS BEING REPORTED PER AWOS OB AT WRAY
COLORADO WITH YUMA WEBCAM SHOWING WHAT APPEARS TO BE LIGHT RAIN.
TEMPERATURES IN THAT AREA CURRENTLY AROUND 36-37F. DESPITE RATHER
LARGE T/TD SPREADS PRECIP IS REACHING THE GROUND.
FOR THE LATEST UPDATE ADJUSTED TEMPERATURES/DEWPOINTS AND WINDS
BASED ON CURRENT OBS AND 23Z HRRR WHICH HAS A VERY GOOD HANDLE ON
CURRENT SITUATION.
COMBINATION OF LOW LEVEL FORCING FROM WIND SHIFT ASSOCIATED WITH
APPROACHING COLD FRONT AND UPPER DISTURBANCE PRODUCING LIGHT
RAIN/SNOW FROM YUMA EAST THROUGH PARTS OF FAR SOUTHWEST NEBRASKA.
CURRENT TREND ON TRACK WITH LATEST FORECAST...ADJUSTMENT WAS MADE
TO UP THE POPS FASTER ACROSS THE FAR NORTH.
WILL AWAIT THE 00Z RUC/HRRR/NAM BEFORE MAKING FURTHER ADJUSTMENTS
THIS EVENING.
UPDATE ISSUED AT 410 PM MST SUN DEC 22 2013
UPDATE REQUIRED TO PUSH BACK ONSET OF SNOWFALL...ESPECIALLY EARLY
TONIGHT. PREVIOUS FORECAST HAD SNOW ALREADY FALLING ACROSS THE
NORTHWEST PORTION OF THE AREA. LATEST MODEL UPDATES...RADAR AND
SFC OBS SHOW SNOW WELL TO THE NORTHWEST OF THE AREA. NOT EXPECTING
ANY PRECIP TO DEVELOP IN THE FORECAST AREA FOR ANOTHER FEW HOURS.
THERE IS ALSO SOME AGREEMENT THAT THERE WILL BE TWO SEPARATE AREAS
OF PRECIPITATION FOCUS...THE FIRST MOVES DOWN FROM WESTERN
NEBRASKA/FAR NORTHEAST COLORADO SLIDING SOUTHEAST AND MAINLY
IMPACTING THE THE NORTHERN THROUGH EASTERN PARTS OF THE AREA. A
SECOND LESS DYNAMIC SYSTEM MOVES DOWN INTO EASTERN COLORADO. THE
HEIGHT OF THE PRECIPITATION AND BEST CHANCE FOR LIGHT SNOWFALL
ACCUMULATIONS WILL BE IN THE 02Z-11Z TIMEFRAME WITH A QUICKLY
DECREASE SHORTLY THEREAFTER. STILL LOOKING AT TOTAL SNOWFALL
AMOUNTS UP TO AN INCH AND A HALF...MAYBE TWO INCHES PRIMARILY
ALONG AND NORTH OF THE KS/NE BORDER WITH DECREASING AMOUNTS AS ONE
TRAVELS SOUTH. FOR THE FAR SOUTHWEST AND SOUTHERN PARTS OF THE
AREA NO SNOWFALL IS EXPECTED AT THIS TIME.
MAY HAVE SOME GUSTY NORTHEAST WINDS TO 25 MPH TONIGHT AS WELL
POSSIBLY CREATING A BIT OF BLOWING SNOW.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 1217 PM MST SUN DEC 22 2013
A NORTHERN STREAM TROUGH WILL PASS THROUGH THE REGION TONIGHT AS A
IT MOVES EAST TOWARD THE GREAT LAKES. A SHORTWAVE WILL DIVE SOUTH ON
THE WEST SIDE OF THE TROUGH ACROSS NORTHWEST KANSAS. NORTHWEST FLOW
WILL FOLLOW ON MONDAY WITH SHORTWAVE RIDGING AND SUBSIDENCE. A
SURFACE COLD FRONT WILL MOVE INTO THE CENTRAL PLAINS TONIGHT WITH
HIGH PRESSURE BUILDING INTO THE REGION MONDAY.
THE SHORTWAVE THAT COMES THROUGH THE FLOW TONIGHT HAS FAVORABLE
PARAMETERS FOR SOME LIGHT SNOW ACROSS MAINLY THE NORTHERN HALF OF
THE FA. FORCING AND ADEQUATE MOISTURE ARE INDICATED AND FORECAST
SOUNDINGS SHOW ICE IN THE COLUMN. MODELS INDICATE THAT SNOW SHOULD
BE ENDING QUICKLY AROUND 12Z MONDAY. TOTAL AMOUNTS SHOULD RANGE
GENERALLY LESS THAN AN INCH AROUND THE I-70 CORRIDOR WITH 1 TO 2
INCHES NORTH OF THE INTERSTATE. SNOW SHOULD BEGIN BY LATE EVENING
ACROSS THE NORTH AND THEN SPREAD SOUTHEAST THROUGH THE REST OF THE
NIGHT. SNOW AMOUNTS AND WIND SHOULD BE BELOW ADVISORY CRITERIA.
SUBSIDENCE WILL MOVE INTO THE FA BEHIND THE WAVE ON MONDAY WITH
CLEARING SKIES.
MIN TEMPERATURES TONIGHT WILL FALL INTO THE TEENS. MAX TEMPERATURES
MONDAY WILL RANGE FROM THE LOWER 20S IN THE EAST TO LOW 30S IN THE
WEST.
.LONG TERM...(THURSDAY THROUGH SUNDAY)
ISSUED AT 254 AM MST MON DEC 23 2013
FOR THE EXTENDED FORECAST...A LARGE UPPER LEVEL PATTERN SHIFT IS
EXPECTED WITH ANOTHER STRONG COLD FRONT PASSAGE THIS WEEKEND.
INITIALLY...A LARGE UPPER LEVEL RIDGE OF HIGH PRESSURE WILL BE IN
PLACE OVER THE ROCKIES FOR THURSDAY AND FRIDAY. ON SATURDAY...A
STRONG SHORTWAVE TROUGH MOVES SOUTHEAST FROM SOUTHWEST CANADA TO THE
GREAT LAKES. THIS STRONG SHORTWAVE WILL FORCE A COLD FRONT SOUTH
WITH A COLD SURFACE HIGH BEHIND IT. THERE ARE SOME DIFFERENCES
BETWEEN THE GFS AND EUROPEAN MODELS IN HANDLING THIS SURFACE HIGH.
THE GFS SHOWS A MUCH STRONGER SURFACE HIGH...1050 MB...AND MUCH
COLDER TEMPERATURES WHILE THE EUROPEAN MODEL ONLY HAS A 1039 SURFACE
HIGH AND NEAR NORMAL TEMPERATURES. BASED ON THE STRENGTH OF THE
FORECAST SHORTWAVE TROUGH AND THE VERY COLD HIGH THAT WAS ABLE TO
DEVELOP THIS WEEKEND OVER CANADA...SIDED WITH THE COLDER SOLUTION
FOR SUNDAY INTO EARLY NEXT WEEK.
UNDER THE RIDGE OF HIGH PRESSURE FOR THURSDAY AND FRIDAY...DRY
WEATHER AND WELL ABOVE NORMAL TEMPERATURES ARE EXPECTED. BASED ON
THE OUTGOING FORECAST WITH THIS PACKAGE...HIGH TEMPERATURES FOR
FRIDAY WOULD BE NEARLY 20 DEGREES ABOVE NORMAL. SOME OF THE GUIDANCE
SUGGESTS EVEN WARMER TEMPERATURES BUT ONLY ADJUSTED UP SLIGHTLY FROM
ALLBLEND IN COLLABORATION WITH NEIGHBORING OFFICES. DRY WEATHER
SHOULD CONTINUE INTO SATURDAY. THE QUESTION OF TEMPERATURES WILL
REMAIN ON SATURDAY DUE TO TIMING OF THE FRONTAL PASSAGE. AS OF RIGHT
NOW...THE FRONT LOOKS TO COME THROUGH LATER IN THE DAY SO ONE LAST
DAY OF MILD TEMPERATURES MAY BE IN STORE.
FOR SATURDAY NIGHT INTO SUNDAY...TEMPERATURES WILL DROP TO NEAR
NORMAL OR SLIGHTLY BELOW NORMAL. IF THE GFS MODEL AND THE STRONGER
ARCTIC SURFACE HIGH PANS OUT...THEN TEMPERATURES WOULD BE COLDER
THAN PRESENTLY ADVERTISED. AS THE SOUTHWESTERN EDGE OF THE SHORTWAVE
TROUGH PASSES OVER...SOME LIGHT SNOW MAY BE POSSIBLE. ONLY LIGHT QPF
WAS SUGGESTED BY THE 00Z MODEL RUNS SO HAVE KEPT POPS AT SLIGHT CHANCE.
THERE APPEARS TO BE SOME DRY AIR THAT WOULD NEED TO BE OVERCOME SO
CONFIDENCE IN THESE POPS IS EVEN SOMEWHAT LOW.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1020 PM MST SUN DEC 22 2013
KGLD...MVFR/IFR CIGS WITH LIGHT SNOW EXPECTED FROM TAF ISSUANCE
THROUGH 08Z OR SO WITH CIG RESTRICTIONS FROM 08Z THROUGH 16Z.
WINDS GENERALLY FROM THE NORTHEAST AT 10-15KTS MAY HAVE SOME
GUSTINESS FOR A SHORT DURATION AS FRONTAL BOUNDARY MOVES THROUGH
IN THE 06Z-08Z TIMEFRAME. AFTER 16Z CIGS QUICKLY RISE TO VFR WITH
ONLY SOME HIGH CLOUDS EXPECTED BY VERY LATE IN THE
AFTERNOON...SLOWLY THICKENING DURING THE NIGHT.
KMCK...MVFR/IFR CIGS WITH LIGHT SNOW EXPECTED THROUGH 09Z OR SO
WITH MVFR CIGS EXPECTED UP THROUGH 22Z OR SO BEFORE QUICKLY RISING
TO VFR SHORTLY AFTER WITH SKC CONDITIONS. WINDS AT TAF ISSUANCE
FROM THE NORTHEAST AT 10-15KTS BECOMING LGT/VRB BY 16Z THEN SLOWLY
BECOMING LIGHT FROM THE EAST/SOUTHEAST UNDER 10KTS THROUGH THE
REST OF THE TAF PERIOD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...99
SHORT TERM...FS
LONG TERM...RRH
AVIATION...99
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1020 PM MST SUN DEC 22 2013
.UPDATE...
ISSUED AT 630 PM MST SUN DEC 22 2013
AT 0130Z LIGHT SNOW WAS BEING REPORTED PER AWOS OB AT WRAY
COLORADO WITH YUMA WEBCAM SHOWING WHAT APPEARS TO BE LIGHT RAIN.
TEMPERATURES IN THAT AREA CURRENTLY AROUND 36-37F. DESPITE RATHER
LARGE T/TD SPREADS PRECIP IS REACHING THE GROUND.
FOR THE LATEST UPDATE ADJUSTED TEMPERATURES/DEWPOINTS AND WINDS
BASED ON CURRENT OBS AND 23Z HRRR WHICH HAS A VERY GOOD HANDLE ON
CURRENT SITUATION.
COMBINATION OF LOW LEVEL FORCING FROM WIND SHIFT ASSOCIATED WITH
APPROACHING COLD FRONT AND UPPER DISTURBANCE PRODUCING LIGHT
RAIN/SNOW FROM YUMA EAST THROUGH PARTS OF FAR SOUTHWEST NEBRASKA.
CURRENT TREND ON TRACK WITH LATEST FORECAST...ADJUSTMENT WAS MADE
TO UP THE POPS FASTER ACROSS THE FAR NORTH.
WILL AWAIT THE 00Z RUC/HRRR/NAM BEFORE MAKING FURTHER ADJUSTMENTS
THIS EVENING.
UPDATE ISSUED AT 410 PM MST SUN DEC 22 2013
UPDATE REQUIRED TO PUSH BACK ONSET OF SNOWFALL...ESPECIALLY EARLY
TONIGHT. PREVIOUS FORECAST HAD SNOW ALREADY FALLING ACROSS THE
NORTHWEST PORTION OF THE AREA. LATEST MODEL UPDATES...RADAR AND
SFC OBS SHOW SNOW WELL TO THE NORTHWEST OF THE AREA. NOT EXPECTING
ANY PRECIP TO DEVELOP IN THE FORECAST AREA FOR ANOTHER FEW HOURS.
THERE IS ALSO SOME AGREEMENT THAT THERE WILL BE TWO SEPARATE AREAS
OF PRECIPITATION FOCUS...THE FIRST MOVES DOWN FROM WESTERN
NEBRASKA/FAR NORTHEAST COLORADO SLIDING SOUTHEAST AND MAINLY
IMPACTING THE THE NORTHERN THROUGH EASTERN PARTS OF THE AREA. A
SECOND LESS DYNAMIC SYSTEM MOVES DOWN INTO EASTERN COLORADO. THE
HEIGHT OF THE PRECIPITATION AND BEST CHANCE FOR LIGHT SNOWFALL
ACCUMULATIONS WILL BE IN THE 02Z-11Z TIMEFRAME WITH A QUICKLY
DECREASE SHORTLY THEREAFTER. STILL LOOKING AT TOTAL SNOWFALL
AMOUNTS UP TO AN INCH AND A HALF...MAYBE TWO INCHES PRIMARILY
ALONG AND NORTH OF THE KS/NE BORDER WITH DECREASING AMOUNTS AS ONE
TRAVELS SOUTH. FOR THE FAR SOUTHWEST AND SOUTHERN PARTS OF THE
AREA NO SNOWFALL IS EXPECTED AT THIS TIME.
MAY HAVE SOME GUSTY NORTHEAST WINDS TO 25 MPH TONIGHT AS WELL
POSSIBLY CREATING A BIT OF BLOWING SNOW.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 1217 PM MST SUN DEC 22 2013
A NORTHERN STREAM TROUGH WILL PASS THROUGH THE REGION TONIGHT AS A
IT MOVES EAST TOWARD THE GREAT LAKES. A SHORTWAVE WILL DIVE SOUTH ON
THE WEST SIDE OF THE TROUGH ACROSS NORTHWEST KANSAS. NORTHWEST FLOW
WILL FOLLOW ON MONDAY WITH SHORTWAVE RIDGING AND SUBSIDENCE. A
SURFACE COLD FRONT WILL MOVE INTO THE CENTRAL PLAINS TONIGHT WITH
HIGH PRESSURE BUILDING INTO THE REGION MONDAY.
THE SHORTWAVE THAT COMES THROUGH THE FLOW TONIGHT HAS FAVORABLE
PARAMETERS FOR SOME LIGHT SNOW ACROSS MAINLY THE NORTHERN HALF OF
THE FA. FORCING AND ADEQUATE MOISTURE ARE INDICATED AND FORECAST
SOUNDINGS SHOW ICE IN THE COLUMN. MODELS INDICATE THAT SNOW SHOULD
BE ENDING QUICKLY AROUND 12Z MONDAY. TOTAL AMOUNTS SHOULD RANGE
GENERALLY LESS THAN AN INCH AROUND THE I-70 CORRIDOR WITH 1 TO 2
INCHES NORTH OF THE INTERSTATE. SNOW SHOULD BEGIN BY LATE EVENING
ACROSS THE NORTH AND THEN SPREAD SOUTHEAST THROUGH THE REST OF THE
NIGHT. SNOW AMOUNTS AND WIND SHOULD BE BELOW ADVISORY CRITERIA.
SUBSIDENCE WILL MOVE INTO THE FA BEHIND THE WAVE ON MONDAY WITH
CLEARING SKIES.
MIN TEMPERATURES TONIGHT WILL FALL INTO THE TEENS. MAX TEMPERATURES
MONDAY WILL RANGE FROM THE LOWER 20S IN THE EAST TO LOW 30S IN THE
WEST.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 155 PM MST SUN DEC 22 2013
DRY AND MILD THROUGH THE LONG TERM WITH A FEW WEAK COLD FRONTS
DURING THE WEEK. ONLY CHANCE OF PRECIP IN THE LONG TERM LOOKS TO BE
ON SATURDAY NIGHT INTO SUNDAY.
MON NIGHT...HIGH PRESSURE WILL BE IN PLACE ACROSS THE CENTRAL AND
NORTHERN PLAINS AS SOUTHWESTERLY MID-LEVEL FLOW BRINGS SOMEWHAT
MILDER AIR TO THE HIGH PLAINS. LOWS WILL BE NEAR NORMAL.
TUESDAY...MILD AS A COLD FRONT APPROACHES FROM THE NORTHWEST. H5
SHORTWAVE RIDGE WILL MOVE ACROSS THE CENTRAL TO NORTHERN PLAINS. AT
THE SURFACE A LEE SIDE TROUGH WILL DEVELOP IN EASTERN COLORADO
DURING THE AFTERNOON WITH THE PRESSURE GRADIENT SUPPORTING A MILD
BREEZE OUT OF THE SOUTH/SOUTHWEST. INCREASING CLOUDS DURING THE
MORNING AND INTO THE AFTERNOON. COLD FRONT WILL MOVE THROUGH IN THE
AFTERNOON BRINGING A WIND SHIFT AND CLEARING SKIES. NAM/NAM 4KM NEST
SPEEDS UP THE FRONTAL TIMING...SO TUESDAY HAS THE POTENTIAL TO TURN
OUT EVEN SUNNIER THAN CURRENTLY FORECAST. REGARDLESS OF
TIMING...PRECIP CHANCES ARE NEAR NIL.
TUESDAY NIGHT...CHRISTMAS EVE...AIR MASS BEHIND THE FRONT IS COOL
AND DRY...AND THUS PRECIPITATION IS NOT EXPECTED. WINDS BECOME LIGHT
BEYOND THE FRONT...AND SKIES WILL BE MOSTLY CLEAR.
WEDNESDAY...CHRISTMAS...SUNNY AND SEASONABLE WITH LIGHT WINDS. HIGH
PRESSURE WILL AGAIN BUILD ACROSS THE CENTRAL PLAINS IN THE WAKE OF
TUESDAY NIGHTS WEAK COLD FRONT...WITH HIGH TEMPS EXPECTED TO BE NEAR
TO ABOVE NORMAL /MID 40S/.
IN THE EXTENDED /WED NIGHT THRU SATURDAY NIGHT/...DRY AND MILD FOR
THE MOST PART WITH CHANCE OF PRECIP OVER THE WEEKEND. A REINFORCING SHOT OF
COLD AIR WILL DROP THROUGH THE NORTHERN PLAINS ON WED NIGHT INTO
THURSDAY...BUT THIS LOOKS TO BE TRENDING FARTHER EAST WITH EACH RUN
OF GUIDANCE. THUS...EXPECT THIS AIR MASS NOT TO EFFECT THE CWA AND
TEMPS TO BE MILD THURSDAY FRIDAY AND SATURDAY. FRI AND SAT LOOK
ESPECIALLY MILD...WITH 850MB TEMPS ABOUT 10 DEG C ABOVE NORMAL AND
SOUTHWESTERLY FLOW FROM THE SURFACE TO ABOUT 850MB. ON SATURDAY
NIGHT A COLD FRONT WILL APPROACH FROM THE NORTH...WHICH WILL BRING A
CHANCE OF PRECIP AND COLDER AIR. SET UP DOES NOT LOOK ESPECIALLY
VIGOROUS...BUT AT THIS POINT LOOKS TO BE THE BEST CHANCE FOR PRECIP
THE AREA HAS SEEN IN A WHILE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1020 PM MST SUN DEC 22 2013
KGLD...MVFR/IFR CIGS WITH LIGHT SNOW EXPECTED FROM TAF ISSUANCE
THROUGH 08Z OR SO WITH CIG RESTRICTIONS FROM 08Z THROUGH 16Z.
WINDS GENERALLY FROM THE NORTHEAST AT 10-15KTS MAY HAVE SOME
GUSTINESS FOR A SHORT DURATION AS FRONTAL BOUNDARY MOVES THROUGH
IN THE 06Z-08Z TIMEFRAME. AFTER 16Z CIGS QUICKLY RISE TO VFR WITH
ONLY SOME HIGH CLOUDS EXPECTED BY VERY LATE IN THE
AFTERNOON...SLOWLY THICKENING DURING THE NIGHT.
KMCK...MVFR/IFR CIGS WITH LIGHT SNOW EXPECTED THROUGH 09Z OR SO
WITH MVFR CIGS EXPECTED UP THROUGH 22Z OR SO BEFORE QUICKLY RISING
TO VFR SHORTLY AFTER WITH SKC CONDITIONS. WINDS AT TAF ISSUANCE
FROM THE NORTHEAST AT 10-15KTS BECOMING LGT/VRB BY 16Z THEN SLOWLY
BECOMING LIGHT FROM THE EAST/SOUTHEAST UNDER 10KTS THROUGH THE
REST OF THE TAF PERIOD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...99
SHORT TERM...FS
LONG TERM...JJM
AVIATION...99
AREA FORECAST DISCUSSION
NWS GRAY ME
402 AM EST MON DEC 23 2013
.SYNOPSIS...
A WAVE OF LOW PRESSURE WILL RIDE NORTHEAST ALONG A COLD FRONT
TODAY. THIS WILL SPREAD FREEZING INTO THE AREA ONCE AGAIN. THE
COLD FRONT WILL FINALLY MOVE OUT TO SEA LATE TODAY. HIGH PRESSURE
WILL THEN BUILD OVER THE REGION TUESDAY AND WEDNESDAY. LOW
PRESSURE WILL PASS NORTH OF THE AREA AND DRAG A TRAILING COLD
FRONT ACROSS THE REGION EARLY FRIDAY FOLLOWED BY HIGH PRESSURE FOR
LATE FRIDAY AND SATURDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
COLD AIR DAMMING REMAINS FIRMLY ENTRENCHED E OF THE MTNS THIS
MORNING. ONLY RELATIVE WARMTH TO BE FOUND ACROSS THE CWFA IS IN
THE CT RIVER VALLEY...WHERE READINGS ARE IN THE MID 30S. THIS IS
THE CRITICAL PART OF THE FORECAST...AS WEAK LOW PRES AND SLUG OF
PCPN LIFTS NEWD ALONG THE EAST COAST.
THRU THIS MORNING THERE IS NO REAL MECHANISM TO SCOUR OUT THE LLVL
COLD AIR. SO THE EXPECTATION IS THAT AREAS BELOW FREEZING WILL
REMAIN THAT WAY...PROBABLY INTO THE AFTERNOON. RECENT RAP AND
HRRR RUNS KEEP MUCH OF THE AREA BELOW FREEZING THRU 18Z. H8 TEMPS
ARE COOLING SLIGHTLY...BUT 06Z GYX SOUNDING CONFIRMS THAT WE STILL
HAVE A WARM NOSE OF +10 C AT 900 MB. AS THE COLUMN RE-SATURATES
AND PCPN BEGINS FALLING...FZRA IS REALLY THE ONLY SCENARIO FOR
MUCH OF THE AREA. THE CT RIVER VALLEY AND POSSIBLY THE IMMEDIATE
COASTLINE WILL SEE JUST RNFL WITH TEMPS ABOVE FREEZING. IN THE
FAR N AROUND JACKMAN...COLD AIR IS STILL DEEP ENOUGH FOR A MIX OF
PL OR SN AT TIMES. NAM12 ACTUALLY HAS A REALLY GOOD HANDLE ON
THERMAL PROFILE ATTM...SO BASED WX GRIDS OFF MODEL THICKNESS
VALUES.
FOR QPF A BLEND OF THE 23/00Z ECMWF AND NERFC WAS PREFERRED. THIS
HAD GENERALLY 0.25 INCHES QPF RUNNING FROM KCON THRU KLEW AND TO KAUG.
THE COAST WAS CLOSE TO 0.50 INCHES. USING THESE VALUES AND
ACCOUNTING FOR SOME LOSS TO RUNOFF AND GRADUAL SURFACE WARMING...ICE
ACCRETION VALUES OF AN ADDITIONAL 0.1 TO 0.25 INCHES IS POSSIBLE.
THE GREATEST THREAT FOR ADDITIONAL SIGNIFICANT ICE ACCUMULATION IS
JUST INLAND FROM THE COAST TO ABOUT A KLEW TO KAUG LINE.
ADDITIONALLY FZRA WILL BE LIKELY DURING THE MORNING
COMMUTE...WHICH WILL ADD TO THE HAZARD.
GIVEN THESE EXPECTATIONS HAVE ADJUSTED HEADLINES TO MATCH. HAVE
DROPPED WARNINGS ACROSS NH...AND CONVERTED COOS COUNTY TO A WINTER
WX ADVISORY. NRN CARROLL COUNTY WILL BE INCLUDED WITH FZRA
ADVISORY TO THE S. WILL ALLOW THE WRN NH ZONES TO EXPIRE MID
MORNING. WINTER STORM WARNINGS IN NRN ME MTNS WILL ALSO BE
DROPPED IN FAVOR OF WINTER WX ADVISORIES FOR COMBINATION OF SN AND
FZRA. ICE STORM WARNINGS WILL REMAIN AS IS. EVEN THOUGH SOME AREAS
MAY NOT SEE 0.5 INCHES OF ICE ACCRETION...CONFUSION OF DOWNGRADING
THE HEADLINE AS FZRA IMPACTS MORNING COMMUTE ARGUED FOR THE
CONTINUITY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/...
S/WV TROF DROPPING THRU THE OHIO VALLEY WILL FINALLY BE THE
IMPETUS THAT PUSHES FRONTAL BOUNDARY THRU THE REGION. AS FLOW
BECOMES NW AND CAA COMMENCES WE WILL FINALLY MIX OUT THE LLVLS OF
THE ATMOSPHERE. GIVEN SUCH WARMTH ALOFT...THIS MAY ACTUALLY CAUSE
TEMPS TO JUMP UP SEVERAL DEGREES IN A SHORT AMOUNT OF TIME. THIS
IS THE MOST LIKELY TIME THAT HIGH TEMPS WILL BE REACHED.
CROSS BARRIER FLOW AND UPPER TROF SWINGING OVERHEAD WILL ALSO
SUPPORT SCT SHSN IN THE MTNS. SEASONABLY COLD AIR LURKING JUST
OVER THE INTERNATIONAL BORDER WILL ONCE AGAIN RETURN FOR THE AREA
TUE...WITH HIGHS REMAINING IN THE 20S.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
MODELS ARE FAIRLY SIMILAR FOR THE THE WEEK. HIGH PRESSURE WILL
BUILD OVER THE AREA TUESDAY AND WEDNESDAY AND MOVE EAST OF THE
AREA THURSDAY. LOW PRESSURE WILL TRAVEL NORTH OF NEW ENGLAND
THROUGH SOUTHERN CANADA THURSDAY AND FRIDAY. A COLD FRONT WILL
MOVE THROUGH MAINE AND NEW HAMPSHIRE LATE THURSDAY NIGHT. A WARM
FRONT WILL MOVE NORTH OF THE AREA FRIDAY OR SATURDAY FOLLOWED BY A
COLD FRONT SUNDAY OR MONDAY. THE MODELS DIFFER ON THE TIMING OF
THE SYSTEM FOR NEXT WEEKEND WITH THE ECMWF BEING SLOWER AND
TRACKING THE SURFACE LOW THROUGH MAINE VERSUS THE GFS TRACKING THE
LOW NORTH OF THE ST LAWRENCE RIVER.
&&
.AVIATION /08Z MONDAY THROUGH FRIDAY/...
SHORT TERM...LIFR AND IFR CONDITIONS WILL CONTINUE INTO THE EARLY
AFTERNOON. FZRA AND FZDZ WILL CONTINUE AS WELL. BY THE LATE
AFTERNOON NW WINDS WILL BEGIN SLOWLY CLEARING AND DRYING THE AREA
OUT FROM W TO E.
LONG TERM...EXPECT VFR THROUGH THE PERIOD.
&&
.MARINE...
SHORT TERM...MARGINAL SCA CONDITIONS WILL CONTINUE INTO THE EARLY
AFTERNOON. WINDS WILL REMAIN MOSTLY BELOW 25 KTS...BUT SEAS WILL
REMAIN NEAR 5 FT. CAA OVER THE WATERS TUE COULD BRINGS WINDS AND
SEAS BACK TO SCA THRESHOLDS.
LONG TERM...SMALL CRAFT CONDITIONS ARE POSSIBLE WEDNESDAY THROUGH FRIDAY.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...WINTER WEATHER ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
MEZ007>009.
ICE STORM WARNING UNTIL NOON EST TODAY FOR MEZ012>014-019>022-
024>028.
FREEZING RAIN ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
MEZ018-023.
NH...WINTER WEATHER ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
NHZ001-002.
FREEZING RAIN ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
NHZ004-006-008>010-013-014.
FREEZING RAIN ADVISORY UNTIL NOON EST TODAY FOR NHZ003-005-007.
MARINE...SMALL CRAFT ADVISORY UNTIL 11 AM EST THIS MORNING FOR ANZ150-
152-154.
&&
$$
LEGRO/HAWLEY
AREA FORECAST DISCUSSION
NWS CARIBOU ME
1240 AM EST MON DEC 23 2013
.SYNOPSIS...
WEAK LOW PRESSURE WILL REMAIN OVER THE GULF OF MAINE THROUGH
MONDAY. COLD HIGH PRESSURE WILL THEN MOVE IN TUESDAY AND
WEDNESDAY.
&&
.NEAR TERM /THROUGH TODAY/...
UPDATE 0035 EST: HAVE ADJUSTED TEMPERATURE...NO OTHER CHANGES.
THE HRRR CONTINUES TO HAVE A PRETTY GOOD HANDLE ON THE AREAS THAT
ARE GETTING PRECIPITATION VERSUS THE AREAS THAT ARE GETTING
FREEZING DRIZZLE OR NOTHING AT ALL. THERE IS A VERY STRONG FRONTAL
BOUNDARY THAT EXTENDS ACROSS CENTRAL NY STATE INTO CENTRAL
MASSACHUSETTS WITH TEMPERATURES NEARLY 30 DEGREES WARMER TO THE
SOUTH OF THIS BOUNDARY. THE FRONT WILL REMAIN WELL SOUTH OF OUR
AREA TONIGHT....HOWEVER...TEMPS RIGHT ALONG THE IMMEDIATE COAST
MAY SLOWLY RISE TO AROUND OR JUST ABOVE FREEZING BY MORNING.
PRECIPITATION THAT IS BREAKING OUT DOWN ACROSS VIRGINIA LATE
THIS EVENING WILL STREAM TO THE NORTHEAST OVERNIGHT AND SHOULD
OVERSPREAD MUCH OF DOWNEAST MAINE BY AROUND 12Z MON MORNING. NO
MAJOR CHANGES TO THE ONGOING FORECAST WITH JUST A FEW TWEAKS.
THE CONCERN REMAINS THAT WHEN THE STEADY PRECIPITATION MOVES BACK
ACROSS DOWNEAST AREAS TOMORROW THAT TEMPERATURES RIGHT ALONG THE
COAST WILL BE ABOVE FREEZING AND ICING MAY NOT END UP BEING A
MAJOR CONCERN FOR THE IMMEDIATE COASTAL COMMUNITIES. BANGOR AND
INLAND AREAS STILL LOOK LIKELY TO SEE ANOTHER ROUND OF FREEZING
RAIN TOMORROW. HAVE ADDRESSED THIS IN FREEZING RAIN ADVISORY BY
ADVERTISING THE GREATEST CONCERN FOR ICING BEING INLAND.
PREVIOUS DISCUSSION... HANCOCK AND WASHINGTON COUNTY HAVE GOTTEN
HIT THE HARDEST WITH THE ICE STORM WITH ABOUT ONE HALF INCH ICE
ACCRETION. SNOW ACCUMULATIONS OVER THE NORTH HAVE BEEN 4 TO 10
INCHES. IN BETWEEN, IT HAS BEEN A MIX OF SNOW, SLEET, AND FREEZING
RAIN WITH GENERALLY SLEET AMOUNTING TO THE MAJORITY OF THE
ACCUMULATIONS. SEE OUR PUBLIC INFORMATION STATEMENT FOR MORE
TOTALS.
THROUGH TONIGHT, BOTTOM LINE IS THAT PRECIPITATION WILL BE QUITE
LIGHT, UNTIL ANOTHER ROUND OF PRECIP MOVES IN DOWNEAST ON
MONDAY. A DEFINITE BREAK BETWEEN SYSTEMS, AND HAVE OPTED TO DROP
ALL THE WARNINGS AND REPLACE IT WITH A WINTER WEATHER ADVISORIES
AND FREEZING RAIN ADVISORIES, EFFECTIVE NOW THROUGH LATE MONDAY,
FOR ALL BUT THE EXTREME NORTH.
LIGHT SLEET, FREEZING DRIZZLE, AND SNIZZLE HAS MADE IT AS FAR
NORTH AS ABOUT CARIBOU THIS EVENING BUT WILL RETREAT SOUTH A BIT
TONIGHT. GENERALLY, FROM MARS HILL NORTH LOOK FOR AN INCH OR TWO
OF MOSTLY SNOW TONIGHT, WITH JUST VERY LIGHT INTERMITTENT
PRECIPITATION SOUTH OF MARS HILL FALLING AS FREEZING DRIZZLE OR
SLEET.
ON MONDAY DURING THE DAY, HOWEVER, HEAVIER PRECIP MOVES BACK IN
MAINLY FROM I-95 SOUTH/EAST. FEEL THAT MOST AREAS EXCEPT PERHAPS
THE VERY IMMEDIATE COAST WILL STAY JUST BELOW FREEZING, WITH
FREEZING RAIN BEING THE PREDOMINANT PRECIP TYPE FOR DOWNEAST WITH
UP TO ONE QUARTER INCH ADDITIONAL ICE ACCRETION. INTO CENTRAL
AREAS, THE PRECIP WILL BE LIGHTER AND WE ARE LOOKING FOR A MIX OF
SNOW, SLEET, AND FREEZING RAIN WITH UP TO ONE TENTH INCH ICE.
ADVISORIES TO COVER THIS EVENT RUN THROUGH THE END OF THE DAY
MONDAY. FELT MOST MODEL GUIDANCE WAS TOO WARM FOR SURFACE TEMPS
FOR MONDAY AND UNDERCUT THEM BY SEVERAL DEGREES.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY/...
A WEAK COASTAL SURFACE LOW PRESSURE SYSTEM WILL BE MOVING INTO THE
CANADIAN MARITIMES MONDAY EVENING AND BRING TO AN END A PROLONGED
PERIOD OF MIXED PRECIPITATION FOR DOWNEAST MAINE. WILL SEE LIGHT
SNOW OR SNOW SHOWERS ACROSS NORTHERN MAINE INTO TUESDAY WITH AN
INVERTED TROUGH. NORTHWEST WINDS WILL PICK UP ON TUESDAY BEHIND
THIS SYSTEM AND MAY CAUSE SOME ISSUES FOR LOCATIONS WITH ICE ON
TREES AND STRUCTURES. COLD CANADIAN HIGH PRESSURE BUILDS INTO
MAINE FOR CHRISTMAS DAY WITH TEMPERATURES AROUND 15 DEGREES BELOW
CLIMATOLOGY.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
THE 12Z ECMWF IS FAR MORE ACTIVE FOR NORTHERN NEW ENGLAND THROUGH
NEXT WEEKEND COMPARED THE 12Z GFS. THE ECWMF AMPLIFIES A CLIPPER
SYSTEM THURSDAY NIGHT AND EARLY FRIDAY IN A SIMILAR MANNER TO A
RECENT STORM ON DECEMBER 17-18. THIS MODEL LATER BRINGS ANOTHER
AREA OF SURFACE LOW PRESSURE ON SUNDAY. THE GFS IS NOTICEABLY
WEAKER WITH BOTH SYSTEMS. LOADED A BLEND OF THESE MODELS WITH AN
EMPHASIS ON THURSDAY NIGHT/FRIDAY AND SUNDAY.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
NEAR TERM: MOSTLY VLIFR TO IFR AT THE TERMINALS THROUGH MONDAY.
PRECIPITATION WILL MAINLY BE SNOW OR A MIX OF SNOW AND SLEET NORTH
OF KPQI AND FREEZING DRIZZLE AT KBGR AND KBHB. STEADIER FREEZING
RAIN WILL DEVELOP AT KBGR MONDAY WITH FREEZING RAIN LIKELY
CHANGING TO RAIN AT KBHB.
SHORT TERM: IFR CIGS AND VSBYS WILL BE POSSIBLE DUE TO SNOW AND/OR
MIXED PRECIPITATION MONDAY NIGHT WITH A DEPARTING WEAK SURFACE LOW
PRESSURE SYSTEM. LIFR/IFR CIGS AND VSBYS WILL BE POSSIBLE THURSDAY
NIGHT AND FRIDAY DUE TO SNOW AND FOG.
&&
.MARINE...
NEAR TERM:
SMALL CRAFT CONDITIONS THROUGH ABOUT MIDDAY MONDAY THEN IMPROVING.
SEAS THIS EVENING AS OF 9 PM ARE RUNNING AROUND 8 FEET AT THE
EASTERN MAINE SHELF WITH A NORTH TO NORTHEAST WIND OF 15 TO 20 KNOTS.
SHORT TERM: NO HEADLINES ARE EXPECTED THROUGH THURSDAY. AN SCA OR GALE
WATCH MAY BE NEEDED THURSDAY NIGHT AND FRIDAY WITH AN AMPLIFYING
CLIPPER SYSTEM.
&&
.EQUIPMENT...
SWITCHED THE RADAR TO CLEAR AIR MODE TO BETTER PICK UP THE
LIGHTER PRECIPITATION FALLING ACROSS THE AREA.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...FREEZING RAIN ADVISORY UNTIL 6 PM EST THIS EVENING FOR MEZ011-
015>017-029-030-032.
WINTER WEATHER ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
MEZ003>006-010-031.
MARINE...SMALL CRAFT ADVISORY UNTIL NOON EST TODAY FOR ANZ050>052.
&&
$$
NEAR TERM...MIGNONE
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1227 AM EST MON DEC 23 2013
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 259 PM EST SUN DEC 22 2013
WATER VAPOR LOOP AND RUC ANALYSIS SHOWS SHORTWAVE AND ASSOC LOW
PRESSURE SYSTEM LIFTING NE THROUGH THE LOWER GREAT LAKES. WEAKENING
LIFT AS NOTED ON MID-LVL Q-VECT ANALYSIS AND EVENTUAL TRANSITION TO
Q-VECT DIVERGENCE HAS QUICKLY DIMINISHED SYSTEM SNOW OVER THE EAST
HALF OF UPPER MI THIS AFTERNOON. TOTAL SYSTEM SNOW ACCUMULATIONS
ACROSS THE SCNTRL AND ERN COUNTIES IN THE WINTER WX ADVISORY AREA
WILL LIKELY END UP IN THE 2 TO 3 INCH RANGE WITH A FEW SPOTS LOCALLY
RECEIVING 4 INCHES. SNOW RATIOS APPEAR TO BE LOWER THAN EXPECTED IN
PREV FCST LEADING TO DIMINISHED SNOW AMTS. SNOWFLAKES HERE AT NWS
MQT ARE QUITE SMALL LEADING TO 6/1 SLR ON THE 18Z. DESPITE
DIMINISHED SNOW AMTS...SMALL FLAKES ARE RESULTING IN REDUCED VSBYS.
SOME ACCIDENTS ALSO REPORTED IN MENOMINEE COUNTY FROM SLIPPERY ROADS
THIS AFTERNOON.
WITH SYSTEM SNOW BASICALLY DONE THIS AFTERNOON...FOCUS WILL SHIFT TO
LES WHICH IS EXPECTED TO IMPACT MAINLY WEST AND NCNTRL COUNTIES
TONIGHT INTO MONDAY EVENING IN NE FLOW.
GRADUALLY COLDER 8H TEMPS MOVING IN FM THE WEST BEHIND DEPARTED LOW
SHOULD ALLOW SNOW RATIOS TO INCREASE THROUGH TONIGHT TO NEAR 20/1
WEST AND NCNTRL AS NOTED ON BUFKIT SNDG DATA. THE INCREASED
INSTABILITY WITH COLDER OVER-WATER TEMPS ALONG WITH DEEPER MOISTURE
AND ENHANCEMENT POTENTIAL FROM APPROACHING MID-LVL TROUGH FM THE NRN
PLAINS SHOULD ALLOW FOR AN UPTICK IN LAKE EFFECT SNOW AMTS TONIGHT
INTO MONDAY FOR FAR WEST AND NCNTRL COUNTIES. NO BIG CHANGES
EXPECTED WITH FORECAST AS LES ADVISORIES STILL LOOK GOOD FOR
GOGEBIC-ONTONAGON AND BARAGA-MARQUETTE COUNTIES HIGHLIGHTING STORM
TOTAL SNOWFALL AMOUNTS POSSIBLY APPROACHING A FOOT OVER THE HIGHER
TERRAIN AREAS FROM NORTH OF KIWD TO THE PORCUPINE MOUNTAINS AND FROM
HERMAN THROUGH HURON MOUNTAINS TO NEGAUNEE. BIGGEST CONCERN OVER THE
WRN COUNTIES IS THAT LES AMOUNTS MAY BE LESS THAN ORIGINALLY
EXPECTED IN IWD AREA AS MODELS APPEAR TO BE HANGING ON TO THE NE
FLOW A BIT LONGER THROUGH TONIGHT WHICH MAY PUSH THE BEST LOW-LVL
CONVERGENCE AND THUS DOMINANT LES BANDS WEST OF KIWD. LES SHOULD
EVENTUALLY PICK UP OVER THE FAR WEST BY MONDAY AFTERNOON AS WINDS
BACK FM NE TO NNE BUT INITIAL LACK OF MODERATE SNOW COULD LIMIT
STORM AMOUNTS IN THE KIWD AREA TO CLOSER TO 8 INCHES. PORCUPINE
MOUNTAINS COULD STILL SEE TOTALS APPROACHING A FOOT THROUGH THE
EVENT.
AS MID-LVL TROUGH AXIS MOVES OVERHEAD LATE MON AFTERNOON...MODELS
SHOW Q-VECT CONV DIMINISHING WHICH SHOULD LIMIT ENHANCEMENT
POTENTIAL AT THAT TIME AND ALLOW FOR LES TO SLOWLY DIMINISH FROM
WEST TO EAST INTO MON EVENING.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 259 PM EST SUN DEC 22 2013
THE UPPER TROUGH AXIS WILL BE OVER CENTRAL UPPER MI AT 00Z
TUE...EXITING E BY 06Z TUE AS AN UPPER RIDGE MOVES TOWARD THE CWA
FROM THE NW. THE RIDGE AXIS MOVES TO THE CENTRAL CWA BY 00Z WED. THE
12Z/22 NAM IS NOT AS STRONG OR AS FAST WITH THE RIDGE THAN THE
GFS/ECMWF/GLOBAL GEM...AND ALSO HAS THE SFC TROUGH BEING STRONGER
WITH A MESO LOW OVER SCENTRAL LAKE SUPERIOR EVEN AFTER THE RIDGE
MOVES OVER. THINK THE SFC TROUGH WILL BE STRONGER THAN THE LARGER
SCALE MODELS SHOW IT...BUT NOT AS STRONG AS THE NAM. EXPECT ONGOING
LES AT THE START OF THE PERIOD TO TAPER OFF THROUGH MON NIGHT INTO
TUE MORNING. GENERALLY...2-4 INCHES OF SNOW CAN BE EXPECTED MON
NIGHT OVER THE HIGHER TERRAIN OF NCENTRAL UPPER MI...WITH OTHER
AREAS NEAR LAKE SUPERIOR SEEING 1-2 INCHES.
MODELS ARE IN GOOD AGREEMENT THAT A SHORTWAVE WILL BRING A QUICK /6
HOUR OR LESS DURATION/ COUPLE OF INCHES OF SNOW TO WEST AND CENTRAL
UPPER MI TUE NIGHT. AS THE SHORTWAVE MOVES ACROSS THE ERN U.P.
CHRISTMAS MORNING...SSE LOW LEVEL WINDS AND 850MB TEMPS AROUND -14C
WILL ALLOW FOR LAKE ENHANCEMENT OFF LAKE MICHIGAN. COULD SEE
ADVISORY LEVEL SNOW AMOUNTS IN EXCESS OF 6 INCHES IN AROUND 12
HOURS. COLDER AIR COMES IN WITH NW LOW LEVEL WINDS LATER CHRISTMAS
DAY...LEADING TO NW WIND LES THAT WILL PERSIST UNTIL A RIDGE PASSES
THU NIGHT INTO FRI. THE CWA MAY SEE ADDITIONAL LIGHT AREA WIDE SNOW
FROM A SHORTWAVE THAT SOME MODELS SHOW MOVING THROUGH...BUT
IF...WHEN AND WHERE ARE QUESTIONS THAT MAKE THIS VERY UNCERTAIN.
ALTHOUGH CONFIDENCE DECREASES FARTHER OUT IN THE FORECAST
PERIOD...MODELS DO GENERALLY AGREE ON MODERATING TEMPERATURES ON SAT
AS A SHORTWAVE MOVES THROUGH THE REGION...WITH TEMPERATURES TURNING
COLDER FOR NEXT SUN. RAN WITH A GENERAL CONSENSUS OF MODEL GUIDANCE
FOR THIS PART OF THE FORECAST.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1226 AM EST MON DEC 23 2013
EXPECT MAINLY MVFR CIGS AND MVFR/IFR VSBY TO PREVAIL OVERNIGHT AND MONDAY
AT SAW AS LOW LEVEL MOISTURE REMAINS OVER THE AREA AND NNE WINDS
PREVAIL ACROSS UPPER MICHIGAN BRINGING LAKE EFFECT SNOW INTO THE TAF
SITES. LOWER VSBYS ARE ALSO EXPECTED TO MOVE INTO IWD AND CMX MONDAY
MORNING AS WINDS BACK MORE NRLY. AS WINDS BECOME LIGHT BY LATE MON
AFTERNOON...THE LES IS EXPECTED TO DIMINISH AS THE SNOWBANDS DO NOT
MOVE AS FAR INLAND. &&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 259 PM EST SUN DEC 22 2013
NORTHEAST WINDS UP TO 30 KNOTS OVER WEST AND NORTH CENTRAL LAKE
SUPERIOR WILL GRADUALLY DIMINISH THROUGH THE AFTERNOON/EARLY EVENING
...BUT GUSTS TO AROUND 25 KNOTS WILL CONTINUE INTO MONDAY. THESE
WINDS ALONG WITH FALLING TEMPS THIS AFTERNOON/EVENING WILL PRODUCE
HEAVY FREEZING SPRAY TODAY THROUGH MONDAY WHEN THE WINDS FINALLY
SLACKEN. WINDS BEGIN TO INCREASE ONCE AGAIN TUESDAY NIGHT INTO
WEDNESDAY AS THE NEXT SYSTEM PASSES TO THE NORTH OF LAKE SUPERIOR.
GALE FORCE GUSTS OVER 35 KNOTS ARE POSSIBLE OVER EASTERN LAKE
SUPERIOR TUESDAY NIGHT AND EARLY WEDNESDAY MORNING. WINDS GRADUALLY
DIMINISH ONCE AGAIN WEDNESDAY NIGHT INTO FRIDAY AS HIGH PRESSURE
STARTS TO BUILD INTO THE REGION.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY UNTIL MIDNIGHT EST /11 PM CST/ TONIGHT
FOR MIZ002-009.
LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST TUESDAY FOR MIZ004-005.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 1 PM EST /NOON CST/ THIS
AFTERNOON FOR LSZ162-263-264.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...TITUS
AVIATION...JLB
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
400 AM CST MON DEC 23 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 356 AM CST MON DEC 23 2013
LIGHT SNOW CONTINUES EARLY THIS MORNING FROM CENTRAL MN THROUGH THE
TWIN CITIES AND WEST CENTRAL WI UNDER AN UPPER LEVEL TROUGH.
ANIMATION OF THE KMPX RADAR INDICATES A LOW/MID LEVEL CIRCULATION
ACROSS CENTRAL MN... WHICH VERIFIES WELL WITH THE RAP AVERAGE
850-700MB HEIGHT FIELD. THE UPPER TROUGH AND LOW LEVEL CYCLONIC
CIRCULATION WILL DRIFT EVER SO SLOWLY TO THE SOUTHEAST THROUGH THIS
EVENING. THIS WILL MAINTAIN PLENTY OF CLOUDS AND LIGHT SNOW ACROSS
EASTERN MN AND WESTERN WI THROUGH THE DAY WITH THE LIGHT SNOW
DIMINISHING ACROSS WEST CENTRAL WI THIS EVENING. SNOW AMOUNTS TODAY
ARE IN THE TRACE TO 1 INCH CATEGORY FOR THE MN CWA WITH 1 TO 2
INCHES FOR WEST CENTRAL WI. SNOW AMOUNTS IN WEST CENTRAL WI TONIGHT
ARE LESS THAN A HALF INCH.
THE TEMPERATURE FORECAST FOR TODAY AND TONIGHT IS RATHER
PROBLEMATIC. ONE CONCERN TODAY IS HOW MUCH OF A REBOUND WE WILL HAVE
ACROSS THE WESTERN HALF OF MINNESOTA AS THE ARCTIC AIR CONTINUES TO
POUR IN WHILE EASTERN AREAS HAVE SOME INSOLATION FROM THE CLOUDS.
JUST ABOUT EVERYBODY IN THE MN RIVER VALLEY EARLY THIS MORNING IS
CURRENTLY NEAR 10 BELOW. LOWS COULD EASILY REACH 15 BELOW TO 20
BELOW ZERO BY DAYBREAK. THE CURRENT THINKING IS THAT WE WILL ONLY
MAKE IF BACK TO THE 5 BELOW TO 10 BELOW RANGE IN THE WEST TODAY WITH
SINGLE DIGITS IN EASTERN MN WITH SOME TEENS IN OUR FAR EASTERN
COUNTIES IN WI. WITH THE ARCTIC HIGH REACHING OUR WESTERN MN
COUNTIES THIS EVENING...TEMPERATURES SHOULD CRATER FOR A 6 TO 8
HOUR PERIOD BEFORE RISING AFTER MIDNIGHT AS SOUTHERLY LOW LEVEL
FLOW DEVELOPS AHEAD OF AN APPROACHING CLIPPER. HENCE... LOWS
TONIGHT ARE A BIG CONCERN. THE GEM AND ECMWF ARE ON THE COLD SIDE
OF GUIDANCE WITH 20 BELOW TO 30 BELOW ZERO FOR MOST OF OUR MN CWA
WITH 10 BELOW TO 20 BELOW ZERO IN WI. THE AREA WHERE THE COLDEST
TEMPERATURES WILL LIKELY BE REACHED IS ACROSS CENTRAL MN WHERE
SEVERAL INCHES OF NEW SNOW HAS FALLEN AND THE SNOW DEPTH IS NEARLY
A FOOT. THEREFORE...WENT NEAR 25 BELOW ACROSS CENTRAL MN WITH 15
BELOW TO 20 BELOW ACROSS SOUTHERN MN WITH AROUND 10 BELOW IN THE
TWIN CITIES AS WEST CENTRAL WI. A NON-DIURNAL TEMPERATURE TREND
WAS INSERTED ACROSS WEST CENTRAL MN DURING THE OVERNIGHT HOURS.
THE COLD TEMPERATURES AND NORTHWEST WINDS OF 10 TO 20 MPH THROUGH
THIS EVENING CERTAINLY SUPPORT THE CURRENT WIND CHILL WARNING AND
WIND CHILL ADVISORY HEADLINES WITH NO CHANGES BEING MADE AT THIS
TIME.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 356 AM CST MON DEC 23 2013
NOT MUCH HAS CHANGED IN THE LONG TERM WITH THIS UPDATE. WE WILL
MAINTAIN NORTHWEST FLOW AS WE REMAIN WEDGED BETWEEN A MEAN ERN PAC
RIDGE AND ERN NOAM TROUGH.
TUESDAY STILL LOOKS TO FEATURE STRONG SOUTHERLY WINDS AND A QUICK
BURST OF SNOW AS THE STRONG WAVE CURRENTLY ROUNDING THE TOP OF THE
RIDGE OVER THE GULF OF ALASKA COMES SLIDING ACROSS THE AREA. MODEL
AGREEMENT REMAINS HIGH WITH THIS SNOW...WITH ONLY MINOR TIMING
DIFFERENCES EXISTING AT THIS POINT. ALL MODELS SHOW FAIRLY
WIDESPREAD 0.1 TO 0.2 INCH QPF AMOUNTS FALLING WITH THIS SYSTEM.
ONLY EXPECT SNOW RATIOS TO RANGE FROM 15-18:1 DURING THE HEAVIEST
SNOW AS COMBINATION OF STRONG WAA IN THE H85-H7 LAYER WILL LIMIT THE
DEPTH OF THE DENDRITIC GROWTH ZONE AND STRONG WINDS FROM THE SFC
THROUGH THE DEPTH OF THE CLOUD LAYER WILL HELP BREAK APART ANY
CRYSTALS THAT TRY TO GET TOO BIG. THESE RATIOS WITH THE EXPECTED QPF
WILL RESULT IN A GOOD 1.5 TO 3.5 INCHES OF SNOW AREA WIDE. NAM/GFS
CONTINUE TO SHOW MIXING RATIOS ON THE 295K SFC UP AROUND 2.5
G/KG...WHICH SUPPORTS THE CURRENTLY EXPECTED SNOWFALL AMOUNTS.
ALTHOUGH THESE AMOUNTS FALL BELOW THE 4 INCH BENCHMARK FOR A WINTER
WEATHER ADVY...THE FACT THAT THIS WILL BE A FAIRLY HEALTHY BURST OF
SNOW FOR ABOUT 4 HOURS DURING THE AFTERNOON/EVENING OF CHRISTMAS EVE
WHEN TRAVEL WILL BE HEAVIER ACROSS THE AREA...FUTURE SHIFTS WILL
HAVE TO WEIGH THE MERITS OF ISSUING AN ADVY BASED ON THE POTENTIAL
TRAVEL IMPACTS.
FOR CHRISTMAS DAY...ANOTHER STRONG UPPER WAVE WILL BE PASSING DOWN
THROUGH THE AREA. THE NAM IS SHOWING HEIGHT FALLS WITH THIS WAVE ON
THE ORDER OF 160M IN 12 HOURS...WITH A 5 UNIT PV ANOMALY COMING DOWN
AS WELL. ALL OF THIS POINTS TO ANOTHER BURST OF SNOW AS THIS COMES
DOWN...THOUGH IT WILL BE COMING DOWN IN THE DRY WAKE OF TUESDAYS
SYSTEM...AS THOSE SPEC HUMIDITIES THAT WILL BE UP AROUND 2.5 G/KG
TUESDAY WILL BE DOWN BETWEEN 0.5 AND 1 G/KG WEDNESDAY...HENCE WHY
QPF INDICATED BY THE MODELS IS SPOTTY AT BEST. THIS JUST LOOKS TO BE
ANOTHER SHOT AT SEEING A FAIRLY WIDESPREAD HALF INCH OF SNOW ON
LIQUID AMOUNTS THAT ARE A TRACE OR A HUNDREDTH OF AN INCH. AFTER
THIS WE MAY SEE REPEAT PERFORMANCES WITH SOME LIGHT SNOW/FLURRIES
AGAIN ON THURSDAY AND FRIDAY AS WE CONTINUE TO GET PEPPERED BY WEAK
UPPER WAVES IN THE NW FLOW. FOR SATURDAY...THE WRN RIDGE LOOKS TO
SHIFT FAR ENOUGH EAST TO PUSH THESE WAVES NORTH OF THE AREA...BUT
THE RETURN OF THE ARCTIC AIR SUNDAY WILL BRING ABOUT THE NEXT SHOT
AT A DUSTING.
TEMPERATURES WILL BE ON A BIT OF A ROLLER COASTER OVER THE NEXT
WEEK...THOUGH WE WILL BE BOUNCING BETWEEN NEAR NORMAL AND ABOUT 20
DEGREES BELOW NORMAL. WE WILL MAINTAIN OUR RESIDENCE IN THE ARCTIC
AIR THROUGH TONIGHT...BRIEFLY SHIFT OUT OF IT TUESDAY THROUGH
WEDNESDAY...RECEIVE A MORE GLANCING BLOW OF ARCTIC AIR WEDNESDAY
NIGHT THROUGH THURSDAY NIGHT...GET OUR WARMEST BREAK FROM THE ARCTIC
AIR FRIDAY AND SATURDAY...THEN SEE WHAT COULD BE OUR COLDEST BLAST
OF AIR YET FOR SATURDAY NIGHT INTO SUNDAY OF NEXT WEEKEND. FROM THE
WIND CHILL HEADLINE END OF THINGS...THE GLANCING BLOW OF ARCTIC AIR
WEDNESDAY NIGHT THROUGH THURSDAY NIGHT LOOKS TO BE JUST WARM ENOUGH
TO CEASE THE NEED FOR ANY WIND CHILL HEADLINES AFTER TUESDAY MORNING
UNTIL THE NEXT HEALTHY DOSE OF ARCTIC AIR RETURNS SUNDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1137 PM CST SUN DEC 22 2013
MVFR CONDITIONS EXPECTED TO PERSIST FOR MUCH OF THE OVERNIGHT AND
INTO MONDAY ACROSS CENTRAL/EASTERN MN AND WESTERN WI. MAINLY VFR
AT AXN AND RWF AS THESE SITES REMAIN ON THE WESTERN PERIPHERY OF
THE SYSTEM GENERATING SNOW TO THE EAST. DRIER AIR WILL FINALLY
PUSH INTO THE REST OF THE TAF SITES LATE MONDAY. NORTHWEST WINDS
AROUND 10 KTS WILL PERSIST THROUGH MONDAY...BECOMING LIGHT AND
VARIABLE MONDAY EVENING.
KMSP...MVFR CONDITIONS THROUGH MOST OF MONDAY IN LIGHT SNOW...WITH
VFR CONDITIONS BY MID AFTERNOON. SNOW ACCUMULATIONS WILL REMAIN
AROUND AN INCH OR LESS.
/OUTLOOK FOR KMSP/
TUE...VFR WITH MVFR/IFR AND -SN BY AFTN. WINDS S AT 10G20KTS.
WED...MVFR WITH -SN/BLSN POSSIBLE. WINDS W AT 15G25KTS.
THU...VFR. WINDS W AT 10KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WIND CHILL ADVISORY UNTIL NOON CST TUESDAY FOR MNZ042-043-
049>051-058-059-066>069-076-077-084-085-091>093.
WIND CHILL WARNING UNTIL NOON CST TUESDAY FOR MNZ041-047-048-
054>057-064-065-073>075-082-083.
WI...NONE.
&&
$$
SHORT TERM...RAH
LONG TERM...MPG
AVIATION...BORGHOFF
AREA FORECAST DISCUSSION...UPDATED
NWS TWIN CITIES/CHANHASSEN MN
1152 PM CST SUN DEC 22 2013
.UPDATE...
ISSUED AT 945 PM CST SUN DEC 22 2013
HAVING A HARD TIME KEEPING UP WITH THE BITTER COLD TEMPERATURES
ACROSS WESTERN MINNESOTA THIS EVENING. THE -10F ISOTHERM IS
BEGINNING TO INCH INTO WESTERN MN...WITH WIND CHILLS IN THE -30S.
THE RAP AND HOPWRF MODELS ARE SHOWING WIDESPREAD -20S FOR AIR
TEMPERATURES IN THOSE AREAS LATE TONIGHT...WITH WIND REMAINING IN
THE 10-15 MPH RANGE. SINCE IT IS SO CLOSE TO WARNING CRITERIA
ALREADY BEFORE 10 PM...UPGRADED MOST OF WESTERN MN AND THE MN
RIVER VALLEY TO A WIND CHILL WARNING. IN ADDITION...HIGHS TOMORROW
WILL STRUGGLE TO GET MUCH ABOVE 10 BELOW IN THESE AREAS AND WIND
CHILLS WILL CONTINUE TO BE IN THE -30S FOR MOST OF THE DAY.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 221 PM CST SUN DEC 22 2013
LIGHT SNOW WILL PERSIST ACROSS THE EASTERN CWA FOR MUCH OF THE
PERIOD...WITH COLD AIR ADVECTION SPREADING ACROSS THE SOUTHWESTERN
PART OF THE CWA. EARLY AFTERNOON WATER VAPOR IMAGERY TOGETHER WITH
500MB HEIGHTS AND WINDS SHOWS A HIGH AMPLITUDE TROUGH ACROSS CENTRAL
NORTH AMERICA...WITH A NORTH/SOUTH ORIENTED JET OVER THE EASTERN
SPINE OF THE ROCKIES. AN AREA OF POSITIVE VORTICITY OWING TO THE
SPEED SHEAR ON THE POLEWARD SIDE OF THIS JET WILL CONTINUE TO ROTATE
ACROSS THE UPPER MIDWEST.
500M HEIGHT FALLS WILL CONTINUE AHEAD OF THIS WAVE ACROSS NORTHERN
MN/WI...RESULTING IN AN INVERTED TROUGH AND PERIODS OF LIGHT SNOW.
NORTHWEST WINDS WILL INCREASE TO AROUND 20MPH AND CONTINUE
OVERNIGHT. THEREFORE HAVE KEPT LOW TEMPERATURES SLIGHTLY ABOVE
GUIDANCE...FAVORING THE SCENARIO OF STRONGER WINDS AND SLIGHTLY
WARMER TEMPERATURES...AS OPPOSED TO WEAKER WINDS AND LOWER TEMPS.
EITHER RESULT STILL PRODUCES WIND CHILL VALUES LESS THAN 25 BELOW
ZERO ACROSS MOST OF THE WESTERN CWA...WHICH WILL REBOUND SLIGHTLY
MONDAY AFTERNOON...BUT FALL OFF AGAIN MONDAY NIGHT. FOR SIMPLICITY/S
SAKE...HAVE GONE WITH ONE LONG WIND CHILL ADVISORY THROUGH TUESDAY
MORNING. THIS WILL LIKELY NEED TO BE EXPANDED FARTHER EAST...AND
PERHAPS UPGRADED TO A WARNING ACROSS THE NORTHWEST MONDAY NIGHT.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 221 PM CST SUN DEC 22 2013
GENERALLY COLD NORTHWEST UPPER FLOW WILL PREDOMINATE THROUGH THE
LONG TERM... WITH PERIODIC CLIPPERS AND REINFORCING SHOTS OF COLD
AIR. THE MAIN FEATURE OF INTEREST WILL BE A SHORTWAVE CURRENTLY
SOUTH OF ALASKA WHICH WILL MOVE THROUGH THE REGION TUESDAY
AFTERNOON AND EVENING... BRINGING A DECENT SHOT OF LIGHT SNOW TO
THE AREA. THE GFS... NAM... AND ECMWF ARE GENERALLY IN GOOD
AGREEMENT ON THE SYSTEM... WITH SOME DIFFERENCES IN TIMING AND
LOCATION OF THE HEAVIEST PCPN. THE THALER-QC DIAGNOSTICS FROM THE
RESPECTIVE MODELS SHOW PCPN TOTALS QUITE SIMILAR TO WHAT IS COMING
DIRECTLY FROM THE MODELS... AND LOCAL LATENT HEAT DEPRIVATION
SENSITIVITY RUNS SHOW MINIMAL DIFFERENCE IN SOLUTIONS. ALL OF THIS
POINTS TOWARD HIGH CONFIDENCE OF A 6 HOUR OR SO WINDOW OF LIGHT TO
MODERATE SNOWFALL. WITH LIQUID PCPN RUNNING FROM A TENTH TO AROUND
A QUARTER OF AN INCH... WOULD EXPECT TO SEE TOTALS GENERALLY IN A
RANGE FROM 1 TO 3 INCHES. MIXING RATIOS OF 2-2.5 G/KG ARE PRESENT
ON THE 290K SURFACE... WHICH WOULD EQUATE TO AROUND 5 INCHES IN 12
HOURS WITH THE IMR METHOD... SO 2.5 INCHES IS PROBABLY ABOUT RIGHT
FOR MOST SPOTS. OF COURSE... MUCH WILL DEPEND ON RATIOS... SO IF
WE SEE RATIOS GET UP NEAR 25 TO 1... THEN WE COULD SEE SOME
LOCALIZED TOTALS TO 4 OR EVEN 5 INCHES. THE FORECAST SOUNDINGS DO
SUGGEST A DECENT DEPTH OF -12 TO -18 C TEMPERATURES IN THE
SATURATED PORTION OF THE PROFILE... SO THE RATIO ISSUE WILL
CERTAINLY NEED TO BE MONITORED. EVEN WITH ONLY A LIGHT SNOW
EXPECTED... IT COULD BE IMPACTFUL GIVEN THAT IT WILL OCCUR DURING
THE LATE AFTERNOON AND EVENING HOURS ON CHRISTMAS EVE... SO IT IS
SOMETHING TRAVELERS WILL NEED TO CONSIDER WHEN MAKING PLANS. ON
CHRISTMAS DAY WE SHOULD EVENTUALLY SEE WEST WINDS PICK UP AND
SHIFT TO THE NORTHWEST LATER IN THE DAY. THE STRONGEST WINDS
SHOULD IMPACT WEST CENTRAL AND SOUTHERN PORTIONS OF THE AREA...
WHICH COULD LEAD TO BLOWING/DRIFTING SNOW ISSUES... WHICH WILL BE
AN ADDITIONAL CONCERN FOR TRAVELERS ON CHRISTMAS DAY.
THE OTHER ISSUE OF CONCERN WILL BE VERY COLD TEMPERATURES AND WIND
CHILLS MONDAY NIGHT INTO TUESDAY MORNING... WITH THE SURFACE RIDGE
SETTLING OVER THE AREA AND A COATING OF FRESH SNOW THANKS TO WHAT
WE/RE SEEING TODAY INTO MONDAY. THE ENTIRE AREA WILL GET WELL
BELOW ZERO... WITH READINGS OF 20 TO 25 BELOW LIKELY OVER PORTIONS
OF THE WEST/NORTHWEST FORECAST AREA. EVEN THE TWIN CITIES METRO
SHOULD SEE READINGS TO NEAR 15 BELOW. THE ONLY AREA WHICH WILL
ESCAPE THE WORST OF THE COLD WILL BE EAST OF I-35 WHERE CLOUDS
LOOK TO HANG ON FOR AT LEAST HALF OF MONDAY NIGHT BEFORE RIDGING
IS SUFFICIENT TO SCOUR THEM OUT. ALTHOUGH WINDS WILL BE LIGHT...
EVEN THE SLIGHT ZEPHYR EXPECTED WILL RESULT IN WIND CHILLS A GOOD
10 TO 15 DEGREES LOWER THAN TEMPERATURES... MEANING SOME LOCATIONS
IN THE NORTHWEST PORTION OF THE AREA COULD SEE WIND CHILLS NEAR 40
BELOW BY 6 AM TUESDAY. DECIDED TO EXTEND THE EXISTING WIND CHILL
ADVISORY THROUGH TUESDAY MORNING FOR NOW... SINCE ADVISORY
CRITERIA ARE PRETTY MUCH ASSURED. LATER SHIFTS CAN LOOK INTO
PERHAPS GOING WITH WIND CHILL WARNINGS FOR A PORTION OF THE AREA
FOR LATE MONDAY NIGHT INTO TUESDAY MORNING.
WE WILL LIKELY KEEP SOME SNOW SHOWERS/FLURRIES AROUND ON CHRISTMAS
DAY AS CYCLONIC FLOW LINGERS... BUT THE MAIN ISSUE IF ANY WILL BE
BLOWING/DRIFTING SNOW AS MENTIONED ABOVE. RIDGING LOOKS TO WORK IN
WEDNESDAY NIGHT THROUGH THURSDAY... WITH COLD AND DRY CONDITIONS
ACROSS THE AREA. NORTHERN PORTIONS OF THE AREA COULD SEE SOME
LIGHT SNOW CHANCES AGAIN OVER THE UPCOMING WEEKEND AS WE SEE A FEW
BRIEF WARM-UPS AND SUBSEQUENT COOL-DOWNS AS CLIPPERS DROP
SOUTHEAST/EAST IN THE NORTHWEST UPPER FLOW ALONG THE CANADIAN
BORDER.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1137 PM CST SUN DEC 22 2013
MVFR CONDITIONS EXPECTED TO PERSIST FOR MUCH OF THE OVERNIGHT AND
INTO MONDAY ACROSS CENTRAL/EASTERN MN AND WESTERN WI. MAINLY VFR
AT AXN AND RWF AS THESE SITES REMAIN ON THE WESTERN PERIPHERY OF
THE SYSTEM GENERATING SNOW TO THE EAST. DRIER AIR WILL FINALLY
PUSH INTO THE REST OF THE TAF SITES LATE MONDAY. NORTHWEST WINDS
AROUND 10 KTS WILL PERSIST THROUGH MONDAY...BECOMING LIGHT AND
VARIABLE MONDAY EVENING.
KMSP...MVFR CONDITIONS THROUGH MOST OF MONDAY IN LIGHT SNOW...WITH
VFR CONDITIONS BY MID AFTERNOON. SNOW ACCUMULATIONS WILL REMAIN
AROUND AN INCH OR LESS.
/OUTLOOK FOR KMSP/
TUE...VFR WITH MVFR/IFR AND -SN BY AFTN. WINDS S AT 10G20KTS.
WED...MVFR WITH -SN/BLSN POSSIBLE. WINDS W AT 15G25KTS.
THU...VFR. WINDS W AT 10KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WIND CHILL ADVISORY UNTIL NOON CST TUESDAY FOR MNZ042-043-
049>051-058-059-066>069-076-077-084-085-091>093.
WIND CHILL WARNING UNTIL NOON CST TUESDAY FOR MNZ041-047-048-
054>057-064-065-073>075-082-083.
WI...NONE.
&&
$$
UPDATE...BORGHOFF
SHORT TERM...TRH
LONG TERM...JRB
AVIATION...BORGHOFF
AREA FORECAST DISCUSSION
NWS TULSA OK
1111 PM CST SUN DEC 22 2013
.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
FOR THE 6Z TAFS... WIDESPREAD MVFR CEILINGS ARE EXPECTED TO
SCATTER OUT FROM THE NORTH OVER THE NEXT FEW HOURS. VFR CONDITIONS
WILL THEN PREVAIL AT ALL SITES FOR THE REMAINDER OF THE FORECAST PERIOD.
&&
.PREV DISCUSSION... /ISSUED 935 PM CST SUN DEC 22 2013/
..UPDATE...
DISCUSSION...
UPDATED FORECAST WILL INCREASE CLOUD COVER THROUGH EARLY MORNING
WITH CLEARING IN LINE WITH LATEST RUC DATA. OVERNIGHT LOWS WERE
CONTINUED THOUGH EASTERN LOCATIONS HAVE MORE UNCERTAINTY PENDING
OVERNIGHT CLOUD COVER TRENDS.
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
AVIATION...06
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1055 PM CST SUN DEC 22 2013
.UPDATE...
ISSUED AT 1007 PM CST SUN DEC 22 2013
TEMPERATURES STILL TRICKY TONIGHT AS CLOUDS ARE IN AND OUT AND WINDS
AT TIMES GO LIGHT. HOWEVER...AFTER COORDINATION WITH OFFICES TO MY
NORTH...OPTED TO UPGRADE MY NORTHERN AREAS TO WIND CHILL WARNING
THROUGH 16Z MONDAY...AS FORECAST WIND CHILLS DROP TO AROUND 35 BELOW
OR A LITTLE COLDER FOR AT LEAST A FEW HOURS IN THE MORNING. RAP MODEL
SHOWING TEMPS MUCH COLDER THAN OTHER MODELS...AND HESITATE TO GO THAT
COLD WITHOUT PRISTINE RADIATIVE CONDITIONS. BUT DID HEDGE IN THAT
DIRECTION IN MY NORTHWEST WHERE KHON HAS ALREADY SHOWN TENDENCY TO
DROP OFF. UPDATED WSW/ZFP HAS BEEN SENT.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 344 PM CST SUN DEC 22 2013
COLD NIGHT AHEAD ACROSS THE REGION AS ARCTIC HIGH PRESSURE BUILDS
INTO THE REGION. WITH COLD CORE SYSTEM BUILDING INTO THE AREA...925
HPA TEMPS WILL FALL TO NEAR -22 C BY TOMORROW MORNING. WITH
NORTHWEST FLOW CONTINUING ACROSS THE AREA...WIND CHILL READINGS WILL
FALL INTO THE DANGEROUS CATEGORY WITH COLDEST READINGS MONDAY
MORNING APPROACHING 35 BELOW ALONG THE HIGHWAY 14 CORRIDOR.
TEMPS WILL BE SLOW TO MODERATE ON MONDAY WITH HIGH PRESSURE SLIDING
EAST ACROSS THE AREA. HAVE LOWERED FORECAST HIGHS...ESPECIALLY IN
THE NORTHEAST PORTION OF THE FORECAST AREA WHERE NORTHWEST FLOW
DOMINATES THROUGHOUT THE DAY EAST OF THE RIDGE AXIS.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 344 PM CST SUN DEC 22 2013
RETURN FLOW DEVELOPS ACROSS THE FORECAST AREA MONDAY NIGHT AS THE
SURFACE HIGH SLIPS TO THE SOUTHEAST. SOUTHERLY WINDS BECOME BREEZY
BY DAYBREAK ACROSS SOUTHEAST SOUTH DAKOTA...WITH A STRONG PUSH OF
WARM AIR ADVECTION SPREADING EASTWARD. TEMPERATURES WILL DROP PRETTY
QUICKLY IN THE EVENING BEFORE EVENTUALLY WARMING AGAIN IN THE EARLY
MORNING HOURS. THIS WILL BE MOST PRONOUNCED IN SOUTH CENTRAL SD
WHERE SOUTHERLY WINDS WILL BE STRONGEST. LOWS WILL STILL BE QUITE
COLD ESPECIALLY ACROSS OUR NORTHEAST WHERE THE ARCTIC AIRMASS
LINGERS. LOWS ARE EXPECTED AS COLD AS THE MID TEENS BELOW ZERO.
ALTHOUGH WARMING DOES OCCUR...INCREASING WINDS WILL STILL RESULT IN
BRUTAL WIND CHILL VALUES OF 20 TO 35 BELOW ZERO FOR ALL BUT THE
MISSOURI VALLEY. HAVE OPTED TO EXTEND THE WIND CHILL ADVISORY IN
THIS AREA THROUGH NOON ON TUESDAY WHEN THE MORE SIGNIFICANT WARMING
FINALLY BUMPS VALUES OUT OF CRITERIA. WHILE HIGH TEMPERATURES SHOULD
IMPROVE TO THE TEENS EAST TO MID 30S IN SOUTH CENTRAL...GUSTY WINDS
AROUND 20 TO 30 MPH THROUGH THE DAY WILL STILL FEEL BRISK.
MODELS REMAIN IN GOOD AGREEMENT IN DRIVING A FRONTAL BOUNDARY AND
SHORTWAVE ACROSS THE NORTHERN PLAINS TUESDAY AFTERNOON AND TUESDAY
NIGHT. CONSISTENT WITH THE LAST FEW MODEL RUNS...THIS WAVE IS A BIT
MORE ROBUST AND SHOULD BRING A HIGH CHANCE OF SOME LIGHT SNOW
THROUGHOUT THE FORECAST AREA. EXPECT SOME LIGHT SNOWFALL TO SPREAD
INTO OUR WESTERN BOUNDARY TUESDAY MORNING AND SPREAD EAST THROUGH
THE DAY. SNOWFALL POTENTIAL APPEARS TO BE BEST ACROSS THE OUR
NORTHERN...CENTRAL AND EASTERN FORECAST AREA WHERE THE MID LEVEL
FRONTOGENESIS AND DIV-Q ARE MORE FAVORABLE....NORTH AND EAST OF A
LINE FROM AROUND HURON TO SIOUX FALLS TO IDA GROVE. THIS ACTIVITY
WILL BE RELATIVELY SHORT LIVED...AND WILL QUICKLY EXIT TO THE EAST
LATE TUESDAY EVENING. SNOWFALL AMOUNTS GENERALLY LOOK TO BE A HALF
INCH OR LESS IN SOUTH CENTRAL SD...RANGING TO AROUND 2 OR 3 INCHES
NEAR THE BUFFALO RIDGE IN SW MN. THE I29 CORRIDOR LOOKS LIKE AROUND
1 TO 2 INCHES.
WINDS WILL ONCE AGAIN BECOME BREEZY FROM THE WEST NORTHWEST ON
CHRISTMAS BUT WITH MORE OF A WESTERLY COMPONENT AND NOT MUCH OF ANY
COLD AIR PUSH BEHIND THE EXITING SYSTEM. THIS WILL KEEP TEMPERATURES
COMPARATIVELY MILD AND MUCH CLOSER TO SEASONAL NORMALS...PRIMARILY
IN THE LOW 20S TO NEAR 30.
COULD SEE ANOTHER WAVE DROP ALONG THE NORTHWEST UPPER LEVEL FLOW
AROUND THE WEDNESDAY NIGHT TIME FRAME...HOWEVER THE STRENGTH AND
TIMING ARE STILL A BIT UNCERTAIN AT THIS TIME. HAVE DECIDED TO GO
AHEAD AND KEEP A MENTION OF A SLIGHT CHANCE OF LIGHT SNOW WED NIGHT
IN OUR NORTHEAST...WHERE THE WAVE LOOKS MOST LIKELY TO TRACK. LOOKS
LIKE IF ANYTHING THIS WOULD BE A QUICK HALF INCH OR LESS OF
SNOWFALL. BIGGEST IMPACT APPEARS TO BE ANOTHER COLD SNAP WITH NEAR
ZERO LOWS WEDNESDAY NIGHT AND THURSDAY NIGHT AND HIGHS ON THURSDAY
IN THE SINGLE DIGITS AND TEENS ABOVE ZERO. AIRMASS DOES MODERATE
AGAIN FOR SATURDAY WITH RETURN FLOW/WARM AIR ADVECTION...BUT THE
ROLLER COASTER TEMPERATURE PATTERN USHERS IN YET ANOTHER POTENTIAL
COLD AIR PUSH ON SUNDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1055 PM CST SUN DEC 22 2013
VFR CONDITIONS EXPECTED THROUGH THE PERIOD. OCCASIONAL WIND GUSTS OF
15-25KT IN SOUTHWEST MN/NORTHWEST IA THROUGH MID AFTERNOON MONDAY
WILL DIMINISH BY SUNSET MONDAY EVENING.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...WIND CHILL ADVISORY UNTIL NOON CST TUESDAY FOR SDZ056-060>062-
066-067-071.
WIND CHILL ADVISORY UNTIL 6 PM CST MONDAY FOR SDZ050-057>059-
063>065-068>070.
WIND CHILL WARNING UNTIL 10 AM CST MONDAY FOR SDZ038>040-052>055.
WIND CHILL ADVISORY FROM 10 AM MONDAY TO NOON CST TUESDAY FOR
SDZ038>040-052>055.
MN...WIND CHILL ADVISORY UNTIL NOON CST TUESDAY FOR MNZ080-081-089-
090-097-098.
WIND CHILL WARNING UNTIL 10 AM CST MONDAY FOR MNZ071-072.
WIND CHILL ADVISORY FROM 10 AM MONDAY TO NOON CST TUESDAY FOR
MNZ071-072.
IA...WIND CHILL ADVISORY UNTIL NOON CST TUESDAY FOR IAZ001>003-
012>014-020>022-031-032.
NE...WIND CHILL ADVISORY UNTIL NOON CST TUESDAY FOR NEZ014.
WIND CHILL ADVISORY UNTIL 6 PM CST MONDAY FOR NEZ013.
&&
$$
UPDATE...JH
SHORT TERM...
LONG TERM...
AVIATION...JH
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1007 PM CST SUN DEC 22 2013
.UPDATE...
ISSUED AT 1007 PM CST SUN DEC 22 2013
TEMPERATURES STILL TRICKY TONIGHT AS CLOUDS ARE IN AND OUT AND WINDS
AT TIMES GO LIGHT. HOWEVER...AFTER COORDINATION WITH OFFICES TO MY
NORTH...OPTED TO UPGRADE MY NORTHERN AREAS TO WIND CHILL WARNING
THROUGH 16Z MONDAY...AS FORECAST WIND CHILLS DROP TO AROUND 35 BELOW
OR A LITTLE COLDER FOR AT LEAST A FEW HOURS IN THE MORNING. RAP MODEL
SHOWING TEMPS MUCH COLDER THAN OTHER MODELS...AND HESITATE TO GO THAT
COLD WITHOUT PRISTINE RADIATIVE CONDITIONS. BUT DID HEDGE IN THAT
DIRECTION IN MY NORTHWEST WHERE KHON HAS ALREADY SHOWN TENDENCY TO
DROP OFF. UPDATED WSW/ZFP HAS BEEN SENT.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 344 PM CST SUN DEC 22 2013
COLD NIGHT AHEAD ACROSS THE REGION AS ARCTIC HIGH PRESSURE BUILDS
INTO THE REGION. WITH COLD CORE SYSTEM BUILDING INTO THE AREA...925
HPA TEMPS WILL FALL TO NEAR -22 C BY TOMORROW MORNING. WITH
NORTHWEST FLOW CONTINUING ACROSS THE AREA...WIND CHILL READINGS WILL
FALL INTO THE DANGEROUS CATEGORY WITH COLDEST READINGS MONDAY
MORNING APPROACHING 35 BELOW ALONG THE HIGHWAY 14 CORRIDOR.
TEMPS WILL BE SLOW TO MODERATE ON MONDAY WITH HIGH PRESSURE SLIDING
EAST ACROSS THE AREA. HAVE LOWERED FORECAST HIGHS...ESPECIALLY IN
THE NORTHEAST PORTION OF THE FORECAST AREA WHERE NORTHWEST FLOW
DOMINATES THROUGHOUT THE DAY EAST OF THE RIDGE AXIS.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 344 PM CST SUN DEC 22 2013
RETURN FLOW DEVELOPS ACROSS THE FORECAST AREA MONDAY NIGHT AS THE
SURFACE HIGH SLIPS TO THE SOUTHEAST. SOUTHERLY WINDS BECOME BREEZY
BY DAYBREAK ACROSS SOUTHEAST SOUTH DAKOTA...WITH A STRONG PUSH OF
WARM AIR ADVECTION SPREADING EASTWARD. TEMPERATURES WILL DROP PRETTY
QUICKLY IN THE EVENING BEFORE EVENTUALLY WARMING AGAIN IN THE EARLY
MORNING HOURS. THIS WILL BE MOST PRONOUNCED IN SOUTH CENTRAL SD
WHERE SOUTHERLY WINDS WILL BE STRONGEST. LOWS WILL STILL BE QUITE
COLD ESPECIALLY ACROSS OUR NORTHEAST WHERE THE ARCTIC AIRMASS
LINGERS. LOWS ARE EXPECTED AS COLD AS THE MID TEENS BELOW ZERO.
ALTHOUGH WARMING DOES OCCUR...INCREASING WINDS WILL STILL RESULT IN
BRUTAL WIND CHILL VALUES OF 20 TO 35 BELOW ZERO FOR ALL BUT THE
MISSOURI VALLEY. HAVE OPTED TO EXTEND THE WIND CHILL ADVISORY IN
THIS AREA THROUGH NOON ON TUESDAY WHEN THE MORE SIGNIFICANT WARMING
FINALLY BUMPS VALUES OUT OF CRITERIA. WHILE HIGH TEMPERATURES SHOULD
IMPROVE TO THE TEENS EAST TO MID 30S IN SOUTH CENTRAL...GUSTY WINDS
AROUND 20 TO 30 MPH THROUGH THE DAY WILL STILL FEEL BRISK.
MODELS REMAIN IN GOOD AGREEMENT IN DRIVING A FRONTAL BOUNDARY AND
SHORTWAVE ACROSS THE NORTHERN PLAINS TUESDAY AFTERNOON AND TUESDAY
NIGHT. CONSISTENT WITH THE LAST FEW MODEL RUNS...THIS WAVE IS A BIT
MORE ROBUST AND SHOULD BRING A HIGH CHANCE OF SOME LIGHT SNOW
THROUGHOUT THE FORECAST AREA. EXPECT SOME LIGHT SNOWFALL TO SPREAD
INTO OUR WESTERN BOUNDARY TUESDAY MORNING AND SPREAD EAST THROUGH
THE DAY. SNOWFALL POTENTIAL APPEARS TO BE BEST ACROSS THE OUR
NORTHERN...CENTRAL AND EASTERN FORECAST AREA WHERE THE MID LEVEL
FRONTOGENESIS AND DIV-Q ARE MORE FAVORABLE....NORTH AND EAST OF A
LINE FROM AROUND HURON TO SIOUX FALLS TO IDA GROVE. THIS ACTIVITY
WILL BE RELATIVELY SHORT LIVED...AND WILL QUICKLY EXIT TO THE EAST
LATE TUESDAY EVENING. SNOWFALL AMOUNTS GENERALLY LOOK TO BE A HALF
INCH OR LESS IN SOUTH CENTRAL SD...RANGING TO AROUND 2 OR 3 INCHES
NEAR THE BUFFALO RIDGE IN SW MN. THE I29 CORRIDOR LOOKS LIKE AROUND
1 TO 2 INCHES.
WINDS WILL ONCE AGAIN BECOME BREEZY FROM THE WEST NORTHWEST ON
CHRISTMAS BUT WITH MORE OF A WESTERLY COMPONENT AND NOT MUCH OF ANY
COLD AIR PUSH BEHIND THE EXITING SYSTEM. THIS WILL KEEP TEMPERATURES
COMPARATIVELY MILD AND MUCH CLOSER TO SEASONAL NORMALS...PRIMARILY
IN THE LOW 20S TO NEAR 30.
COULD SEE ANOTHER WAVE DROP ALONG THE NORTHWEST UPPER LEVEL FLOW
AROUND THE WEDNESDAY NIGHT TIME FRAME...HOWEVER THE STRENGTH AND
TIMING ARE STILL A BIT UNCERTAIN AT THIS TIME. HAVE DECIDED TO GO
AHEAD AND KEEP A MENTION OF A SLIGHT CHANCE OF LIGHT SNOW WED NIGHT
IN OUR NORTHEAST...WHERE THE WAVE LOOKS MOST LIKELY TO TRACK. LOOKS
LIKE IF ANYTHING THIS WOULD BE A QUICK HALF INCH OR LESS OF
SNOWFALL. BIGGEST IMPACT APPEARS TO BE ANOTHER COLD SNAP WITH NEAR
ZERO LOWS WEDNESDAY NIGHT AND THURSDAY NIGHT AND HIGHS ON THURSDAY
IN THE SINGLE DIGITS AND TEENS ABOVE ZERO. AIRMASS DOES MODERATE
AGAIN FOR SATURDAY WITH RETURN FLOW/WARM AIR ADVECTION...BUT THE
ROLLER COASTER TEMPERATURE PATTERN USHERS IN YET ANOTHER POTENTIAL
COLD AIR PUSH ON SUNDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 528 PM CST SUN DEC 22 2013
VFR CONDITIONS AND NORTHWEST FLOW WILL CONTINUE THROUGH THE TAF
PERIOD WITH ARCTIC AIRMASS ACROSS THE REGION. SPOTTY FLURRIES ARE
POSSIBLE FROM 4-6K FOOT STRATUS DECK EAST OF I-29...MAINLY BEFORE
06Z...BUT NOT EXPECTED TO IMPACT TAF LOCATIONS.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...WIND CHILL ADVISORY UNTIL NOON CST TUESDAY FOR SDZ056-060>062-
066-067-071.
WIND CHILL ADVISORY UNTIL 6 PM CST MONDAY FOR SDZ050-057>059-
063>065-068>070.
WIND CHILL WARNING UNTIL 10 AM CST MONDAY FOR SDZ038>040-052>055.
WIND CHILL ADVISORY FROM 10 AM MONDAY TO NOON CST TUESDAY FOR
SDZ038>040-052>055.
MN...WIND CHILL ADVISORY UNTIL NOON CST TUESDAY FOR MNZ080-081-089-
090-097-098.
WIND CHILL WARNING UNTIL 10 AM CST MONDAY FOR MNZ071-072.
WIND CHILL ADVISORY FROM 10 AM MONDAY TO NOON CST TUESDAY FOR
MNZ071-072.
IA...WIND CHILL ADVISORY UNTIL NOON CST TUESDAY FOR IAZ001>003-
012>014-020>022-031-032.
NE...WIND CHILL ADVISORY UNTIL NOON CST TUESDAY FOR NEZ014.
WIND CHILL ADVISORY UNTIL 6 PM CST MONDAY FOR NEZ013.
&&
$$
UPDATE...JH
SHORT TERM...
LONG TERM...
AVIATION...JH
AREA FORECAST DISCUSSION
NWS PUEBLO CO
902 AM MST MON DEC 23 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 245 AM MST MON DEC 23 2013
CURRENTLY...
ANOTHER SURGE OF COOLER AIR WAS MOVING ACROSS THE PLAINS AT 2AM. LOW
CLOUDS EXTENDED FROM NE EL PASO COUNTY EASTWARD TO KIOWA COUNTY.
OVER THE C MTN REGION LIGHT SNOW WAS NOTED. OTHERWISE...IT WAS
MOSTLY CLEAR OVER THE REGION.
TODAY..
IN THE SHORT TERM...EARLY THIS MORNING...HRRR SHOWS CLOUDS
INCREASING OVER THE PLAINS AND THE NDFD WAS DRAWN UP TO ACCOUNT FOR
THESE INCREASING CLOUDS. HOWEVER...BY MID MORNING...CLOUDS SHOULD
DECREASE RAPIDLY OVER MOST OF THE PLAINS AS WESTERLY SFC FLOW
DEVELOPS AS A LEE TROUGH SETS UP OVER THE PLAINS. THIS TROUGH WILL
SET UP N-S IN THE VICINITY OF KLAA. TO THE EAST OF THE TROUGH COOLER
SOUTHERLY FLOW WILL OCCUR AND TEMPS WILL NOT BE AS HIGH AS TEMPS TO
THE WEST OF THE SFC TROUGH AXIS. EXPECT HIGHS ON THE PLAINS WEST OF
THE LEE TROUGH TO BE IN THE 40S...WHILE 30S WILL OCCUR EAST OF IT.
THE SAN LUIS VALLEY WILL REMAIN TRAPPED IN THE INVERSION AND EXPECT
MAINLY L20S IN THE VALLEY. WE MAY SEE SOME GROUND FOG IN THE VALLEY
EARLY THIS MORNING.
LIGHT SNOW SHOWERS WILL CONTINUE OVER THE C MTNS TODAY.
TONIGHT...
ANOTHER DISTURBANCE IN THE NW FLOW WILL RAPIDLY MOVE TOWARDS THE
REGION TOWARDS SUNRISE TUESDAY. THE MAIN AFFECTS OF THIS SYSTEM WILL
BE INCREASING SNOW FOR THE C MTNS ONCE AGAIN. ALSO WESTERLY SFC FLOW
OVER THE E SLOPES OF THE MTNS WILL ALLOW FOR RELATIVELY WARMER MIN
TEMPS TO OCCUR IN THE TYPICAL BANANA BELT REGIONS.
GUSTY WINDS WILL OCCUR IN THE MTNS...ESPECIALLY THE C
MTNS...SANGRES...WETS AND PIKE PEAK. WE MAY SEE SOME LOCALLY GUSTY
WINDS ON THE RAMPARTS TOWARDS SUNRISE.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 245 AM MST MON DEC 23 2013
...DRY WEATHER FOR THE REST OF 2013....
UNEVENTFUL WEATHER PATTERN SHOWS NO SIGN OF LETTING UP...AS A
PERSISTENT BLOCK OVER THE ERN PACIFIC AND WRN SATES KEEPS DISTURBANCES
FROM MOVING INTO THE ROCKIES.
TUESDAY...THE SRN END OF A SHORT WAVE MOVING THROUGH THE NRN PLAINS
WILL BRUSH THROUGH CO DURING THE AFTERNOON. THE ECMWF AND GFS
CONTINUE TO INDICATE SOME VERY LIGHT QPF OVER THE PALMER DVD AND
PORTIONS OF THE PLAINS...BUT LOOKING AT THE SOUNDINGS IT LOOKS LIKE
THIS PRECIP IS GENERATED FROM A RELATIVELY SHALLOW SATURATED LAYER
FROM AROUND H5-H6. UPPER LEVELS AND LOWEST LEVELS LOOK PRETTY DRY.
THE NAM DOES NOT EVEN HAVE THE MOIST LAYER AND KEEPS OUR AREA
COMPLETELY DRY EXCEPT FOR THE EXPECTED LIGHT SHSN OVER LAKE COUNTY.
SUSPECT THERE WILL BE SOME LIGHT FLURRIES OR SHOWERS AT BEST...SO
WILL KEEP POPS SILENT OVER THE PLAINS. MAIN IMPACT FROM THE
DISTURBANCE WILL BE SOME BREEZY CONDITIONS OVER THE MTS DURING THE
MORNING AND AFTERNOON...AND SOME GUSTY N WINDS OVER THE PLAINS IN THE
AFTERNOON. LIGHT W-NW FLOW CONTINUES ON WED...AND WOULD NOT BE
SURPRISED TO SEE TEMPS COME IN A BIT HIGHER THAN CURRENTLY
FORECAST...BUT IT WILL BE COOLER ON CHRISTMAS.
THE UPPER RIDGE BUILDS STRONGLY ON THU AND FRIDAY...AND WE ARE BACK
TO ABOVE AVERAGE TEMPS AND CONTINUED VERY DRY CONDITIONS. TEMPS COULD
RISE INTO THE 60S ON FRIDAY BEFORE THE NEXT SYSTEM MOVES IN FROM THE
NW NEXT WEEKEND. THIS FRONT LOOKS SIMILAR TO WHAT WE HAVE BEEN
SEEING...NOT MUCH CHANCE FOR ANY SIGNIFICANT PRECIP. AT SOME POINT
A CUTOFF LOW OVER THE CA COAST WILL EJECT EWD INTO OUR AREA...BUT
WITHOUT ANY STRONG PACIFIC JET SUPPORT IT LOOKS LIKE MORE OF THE
SAME FOR US...DRY AND MILD. HOPEFULLY THE PATTERN WILL BECOME MORE
ACTIVE IN JANUARY OR ALL THE GAINS WE MADE EARLY THIS SEASON IN THE
MT SNOWPACK WILL BE LOST. ROSE
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 857 AM MST MON DEC 23 2013
EASTERLY UPSLOPE FLOW HAS BROUGHT STRATUS WITH MVFR CIGS TO
PORTIONS OF THE SOUTHEAST PLAINS. THESE HAVE SPREAD INTO BOTH THE
KCOS AND KPUB TERMINALS WITH LIFR CIGS AT KCOS WHERE UPSLOPE HAS
CAUSED FOG AND EVEN FLURRIES TO FORM ON THE SOUTHERN SLOPES OF THE
PALMER DIVIDE. RAP MODEL SEEMS TO HAVE CAUGHT ON TO THIS FAIRLY
WELL AND HAS CIGS DISSIPATING FOR KCOS AND KPUB BY 18Z. HAVE
INTRODUCED SOME CIGS INTO KPUB...AND WILL MONITOR THE END TIME OF
17Z AT KCOS AS THIS MAY NEED TO BE EXTENDED ANOTHER HOUR BASED ON
LATEST SATELLITE TRENDS. -KT
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...HODANISH
LONG TERM...ROSE
AVIATION...KT
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
904 AM CST Mon Dec 23 2013
.UPDATE...
ISSUED AT 901 AM CST MON DEC 23 2013
Updated pops, QPF, snow amounts, and sky to account for the small snow
band that is moving across south central Kansas this morning. Snow
accumulations will be under an inch with this activity.
&&
.SYNOPSIS...
ISSUED AT 850 AM CST MON DEC 23 2013
The 23.12Z 250 hPa map showed a highly meridional flow pattern across
North America with northwesterly flow extending from the western Canadian
prairies down towards the southern Rockies. Peak magnitudes were around
110 kt. More impressively, very strong southwesterly flow extended
downstream of a longwave trof axis with peak magnitudes around 200 kt
at Sept-Iles, QB. At 500 hPa, cold mid-level temperatures advected in
the wake of trof with values at -32C at KDDC. The overall height pattern
showed a trof axis from Ontario to western Texas. Another trof was moving
onshore across British Columbia. At 700 hPa, neutral temperature change
was noted at KDDC with the baroclinic boundary north of the forecast
area. Slight warming was noted at 850 hPa for KDDC, up to -3C versus
-7C 24 hours ago. More importantly, all the really cold air at these
two constant pressure levels was north and northeast of the forecast
area of responsibility. At the sfc, a stationary was backed up to the
lee of the Rockies. KDDC WSR-88D in combination with surface observations
indicated light snow across south central Kansas.
&&
.SHORT TERM...(Today and tonight)
ISSUED AT 344 AM CST MON DEC 23 2013
A deep upper level trough was pushing into the upper Midwest early
this morning, and cold surface high pressure was building
southward in its wake. Some light snow was noted over northern
Kansas along the low to mid level baroclinic zone. But only very
light accumulations are expected through 12-14z. The arctic surge
will occur this morning, with a weakening pressure gradient by
this afternoon. High temperatures will only be in the upper teens
over the snow covered locations such as Dodge City and Larned,
with some 20s over places with bare ground such as Garden City,
Syracuse and Scott City. Low stratus will develop this morning
as the cold advection spreads southward, but should erode by
this afternoon with daytime heating. This cold surge will be very
short lived since the next rapidly advancing shortwave trough will
have moved over the western pacific into the western and northern
United States instead of through Canada. Surface pressures will
fall rapidly ahead of this feature tonight given the mid level
flow across the Rockies, resulting in breezy south winds. Stronger
south winds on the back side of an arctic airmass can feel quite
chilly, and tonight will be no exception. Temperatures will start
out cold, and despite the south winds, will fall well down into
the lower teens, along with some single digits over snow covered
areas. The south winds will eventually result in a warm up, which
is described below in the long term discussion.
.LONG TERM...(Tuesday through Sunday)
ISSUED AT 254 AM CST MON DEC 23 2013
An upper level trough, which was located over the Gulf of Alaska
earlier this morning, will move out of the northern Rockies and
out into the plains on Tuesday. As this next system passes, a cold
front will drop south across western Kansas. At this time moisture
appears to be mainly confined to the mid and upper levels so the
chance of precipitation still appears small, however there will be
an increase in cloud cover late Tuesday and Tuesday night. Prior
to the frontal passage the 850mb temperatures from the GFS and NAM
are forecast to range from 4c to 8c which when mixing these
temperatures down to the surface suggests that highs in the lower
50s will still be possible in areas without snow cover Tuesday
afternoon given full sun. In areas where snow cover remains the
highs are expected to average around 15 degrees cooler.
On Wednesday the net 24 hour change in the 925mb and 850mb
temperatures varies from -2 to -4c so a minor cool down is
expected behind the cold front mid week. By late week westerly
downslope flow will improve with 850mb temperatures trends
indicating temperatures will warm out of the upper 30s to mid 40s
and into at least the lower 50s on Friday and Saturday.
Temperatures will be cooler in areas when some snow cover remains
late week and early this weekend.
&&
.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
ISSUED AT 504 AM CST MON DEC 23 2013
BUFR soundings and HRRR suggesting a period of IFR status cigs
will be possible early this morning behind a cold front which at
10z was located just south of DDC and GCK. Surface observations
and satellite loop not supporting this trend at this time, however
with more of an easterly upslope flow developing early this
morning between 12z and 18z will introduce low MVFR cigs and even
a period of 3-5sm BR. A few flurries will be possible early this
morning also ahead of an upper level trough that will cross
western Kansas between 12z and 18z. Once this upper trough passes
VFR conditions will develop at all three taf sites. Gusty
northeast winds at immediately behind this front will subside to
less than 10kts by 18z as an area of high pressure at the surface
builds into the area from the north.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 18 11 39 16 / 10 0 10 0
GCK 21 12 49 17 / 10 0 0 0
EHA 24 18 49 19 / 0 0 0 10
LBL 20 11 45 20 / 0 0 0 0
HYS 18 11 43 20 / 30 0 10 10
P28 21 10 35 15 / 50 0 10 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Sugden
SYNOPSIS...Sugden
SHORT TERM...Finch
LONG TERM...Burgert
AVIATION...Burgert
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
850 AM CST Mon Dec 23 2013
...Update to synopsis...
.SYNOPSIS...
ISSUED AT 850 AM CST MON DEC 23 2013
The 23.12Z 250 hPa map showed a highly meridional flow pattern across
North America with northwesterly flow extending from the western Canadian
prairies down towards the southern Rockies. Peak magnitudes were around
110 kt. More impressively, very strong southwesterly flow extended
downstream of a longwave trof axis with peak magnitudes around 200 kt
at Sept-Iles, QB. At 500 hPa, cold mid-level temperatures advected in
the wake of trof with values at -32C at KDDC. The overall height pattern
showed a trof axis from Ontario to western Texas. Another trof was moving
onshore across British Columbia. At 700 hPa, neutral temperature change
was noted at KDDC with the baroclinic boundary north of the forecast
area. Slight warming was noted at 850 hPa for KDDC, up to -3C versus
-7C 24 hours ago. More importantly, all the really cold air at these
two constant pressure levels was north and northeast of the forecast
area of responsibility. At the sfc, a stationary was backed up to the
lee of the Rockies. KDDC WSR-88D in combination with surface observations
indicated light snow across south central Kansas.
&&
.SHORT TERM...(Today and tonight)
ISSUED AT 344 AM CST MON DEC 23 2013
A deep upper level trough was pushing into the upper Midwest early
this morning, and cold surface high pressure was building
southward in its wake. Some light snow was noted over northern
Kansas along the low to mid level baroclinic zone. But only very
light accumulations are expected through 12-14z. The arctic surge
will occur this morning, with a weakening pressure gradient by
this afternoon. High temperatures will only be in the upper teens
over the snow covered locations such as Dodge City and Larned,
with some 20s over places with bare ground such as Garden City,
Syracuse and Scott City. Low stratus will develop this morning
as the cold advection spreads southward, but should erode by
this afternoon with daytime heating. This cold surge will be very
short lived since the next rapidly advancing shortwave trough will
have moved over the western pacific into the western and northern
United States instead of through Canada. Surface pressures will
fall rapidly ahead of this feature tonight given the mid level
flow across the Rockies, resulting in breezy south winds. Stronger
south winds on the back side of an arctic airmass can feel quite
chilly, and tonight will be no exception. Temperatures will start
out cold, and despite the south winds, will fall well down into
the lower teens, along with some single digits over snow covered
areas. The south winds will eventually result in a warm up, which
is described below in the long term discussion.
.LONG TERM...(Tuesday through Sunday)
ISSUED AT 254 AM CST MON DEC 23 2013
An upper level trough, which was located over the Gulf of Alaska
earlier this morning, will move out of the northern Rockies and
out into the plains on Tuesday. As this next system passes, a cold
front will drop south across western Kansas. At this time moisture
appears to be mainly confined to the mid and upper levels so the
chance of precipitation still appears small, however there will be
an increase in cloud cover late Tuesday and Tuesday night. Prior
to the frontal passage the 850mb temperatures from the GFS and NAM
are forecast to range from 4c to 8c which when mixing these
temperatures down to the surface suggests that highs in the lower
50s will still be possible in areas without snow cover Tuesday
afternoon given full sun. In areas where snow cover remains the
highs are expected to average around 15 degrees cooler.
On Wednesday the net 24 hour change in the 925mb and 850mb
temperatures varies from -2 to -4c so a minor cool down is
expected behind the cold front mid week. By late week westerly
downslope flow will improve with 850mb temperatures trends
indicating temperatures will warm out of the upper 30s to mid 40s
and into at least the lower 50s on Friday and Saturday.
Temperatures will be cooler in areas when some snow cover remains
late week and early this weekend.
&&
.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
ISSUED AT 504 AM CST MON DEC 23 2013
BUFR soundings and HRRR suggesting a period of IFR status cigs
will be possible early this morning behind a cold front which at
10z was located just south of DDC and GCK. Surface observations
and satellite loop not supporting this trend at this time, however
with more of an easterly upslope flow developing early this
morning between 12z and 18z will introduce low MVFR cigs and even
a period of 3-5sm BR. A few flurries will be possible early this
morning also ahead of an upper level trough that will cross
western Kansas between 12z and 18z. Once this upper trough passes
VFR conditions will develop at all three taf sites. Gusty
northeast winds at immediately behind this front will subside to
less than 10kts by 18z as an area of high pressure at the surface
builds into the area from the north.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 18 11 39 16 / 10 0 10 0
GCK 21 12 49 17 / 10 0 0 0
EHA 24 18 49 19 / 0 0 0 10
LBL 20 11 45 20 / 0 0 0 0
HYS 18 11 43 20 / 30 0 10 10
P28 21 10 35 15 / 20 0 10 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...Sugden
SHORT TERM...Finch
LONG TERM...Burgert
AVIATION...Burgert
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
507 AM CST Mon Dec 23 2013
...Updated aviation discussion...
.SHORT TERM...(Today and tonight)
ISSUED AT 344 AM CST MON DEC 23 2013
A deep upper level trough was pushing into the upper Midwest early
this morning, and cold surface high pressure was building
southward in its wake. Some light snow was noted over northern
Kansas along the low to mid level baroclinic zone. But only very
light accumulations are expected through 12-14z. The arctic surge
will occur this morning, with a weakening pressure gradient by
this afternoon. High temperatures will only be in the upper teens
over the snow covered locations such as Dodge City and Larned,
with some 20s over places with bare ground such as Garden City,
Syracuse and Scott City. Low stratus will develop this morning
as the cold advection spreads southward, but should erode by
this afternoon with daytime heating. This cold surge will be very
short lived since the next rapidly advancing shortwave trough will
have moved over the western pacific into the western and northern
United States instead of through Canada. Surface pressures will
fall rapidly ahead of this feature tonight given the mid level
flow across the Rockies, resulting in breezy south winds. Stronger
south winds on the back side of an arctic airmass can feel quite
chilly, and tonight will be no exception. Temperatures will start
out cold, and despite the south winds, will fall well down into
the lower teens, along with some single digits over snow covered
areas. The south winds will eventually result in a warm up, which
is described below in the long term discussion.
.LONG TERM...(Tuesday through Sunday)
ISSUED AT 254 AM CST MON DEC 23 2013
An upper level trough, which was located over the Gulf of Alaska
earlier this morning, will move out of the northern Rockies and
out into the plains on Tuesday. As this next system passes, a cold
front will drop south across western Kansas. At this time moisture
appears to be mainly confined to the mid and upper levels so the
chance of precipitation still appears small, however there will be
an increase in cloud cover late Tuesday and Tuesday night. Prior
to the frontal passage the 850mb temperatures from the GFS and NAM
are forecast to range from 4c to 8c which when mixing these
temperatures down to the surface suggests that highs in the lower
50s will still be possible in areas without snow cover Tuesday
afternoon given full sun. In areas where snow cover remains the
highs are expected to average around 15 degrees cooler.
On Wednesday the net 24 hour change in the 925mb and 850mb
temperatures varies from -2 to -4c so a minor cool down is
expected behind the cold front mid week. By late week westerly
downslope flow will improve with 850mb temperatures trends
indicating temperatures will warm out of the upper 30s to mid 40s
and into at least the lower 50s on Friday and Saturday.
Temperatures will be cooler in areas when some snow cover remains
late week and early this weekend.
&&
.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
ISSUED AT 504 AM CST MON DEC 23 2013
BUFR soundings and HRRR suggesting a period of IFR status cigs
will be possible early this morning behind a cold front which at
10z was located just south of DDC and GCK. Surface observations
and satellite loop not supporting this trend at this time, however
with more of an easterly upslope flow developing early this
morning between 12z and 18z will introduce low MVFR cigs and even
a period of 3-5sm BR. A few flurries will be possible early this
morning also ahead of an upper level trough that will cross
western Kansas between 12z and 18z. Once this upper trough passes
VFR conditions will develop at all three taf sites. Gusty
northeast winds at immediately behind this front will subside to
less than 10kts by 18z as an area of high pressure at the surface
builds into the area from the north.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 18 11 39 16 / 10 0 10 0
GCK 21 12 49 17 / 10 0 0 0
EHA 24 18 49 19 / 10 0 0 10
LBL 20 11 45 20 / 10 0 0 0
HYS 18 11 43 20 / 20 0 10 10
P28 21 10 35 15 / 30 0 10 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Finch
LONG TERM...Burgert
AVIATION...Burgert
AREA FORECAST DISCUSSION
NWS GRAY ME
939 AM EST MON DEC 23 2013
.SYNOPSIS...
A WAVE OF LOW PRESSURE WILL RIDE NORTHEAST ALONG A COLD FRONT
TODAY. THIS WILL SPREAD FREEZING RAIN AND A WINTRY MIX OF
PRECIPITATION INTO THE AREA ONCE AGAIN. THE COLD FRONT WILL
FINALLY MOVE OUT TO SEA LATE TODAY. HIGH PRESSURE AND COLDER AIR WILL
THEN BUILD OVER THE REGION FOR THE MIDWEEK PERIOD. LOW PRESSURE
WILL PASS NORTH OF THE AREA AND DRAG A TRAILING COLD FRONT ACROSS
THE REGION EARLY FRIDAY FOLLOWED BY HIGH PRESSURE FOR LATE FRIDAY
AND SATURDAY.
&&
.NEAR TERM /UNTIL 5 PM THIS AFTERNOON/...
935 AM...THIS FINAL ROUND OF FREEZING RAIN WILL PRODUCE UP TO AN
ADDITIONAL 1/3 TO AS MUCH AS 1/2 INCH OF ICE BEFORE IT ENDS FROM
SOUTHWEST TO NORTHEAST ACROSS THE AREA DURING THE AFTERNOON HOURS.
THE ICE STORM WARNING HAS BEEN EXTENDED THROUGH 4 PM SINCE THIS
AREA HAD THE GREATEST ICE ACCRETION PRIOR TO TODAY`S EVENT AND IS
MOST VULNERABLE TO THE ADDITIONAL GLAZE. ELSEWHERE...I EXPECT TOTAL
ICE ACCRETION TO BE UNDER 1/2 INCH AND IN THE ADVISORY CATEGORY.
PREV DISC...
659 AM...I MADE SOME MINOR ADJUSTMENTS TO 1ST PERIOD GRIDS TO
REFLECT CURRENT MESONET AS WELL AS RADAR TRENDS. ON THE WATERS...I
EXTENDED THE CURRENT SMALL CRAFT ADVISORY THROUGH LATE TONIGHT.
PREV DISC...
UPDATE...MADE A FEW MINOR CHANGES TO THE GRIDS TO ACCOUNT FOR
CURRENT OBSERVATIONAL TRENDS. HAVE ALSO DELAYED THE TIMING OF
CATEGORICAL POP UNTIL AFTER 12Z BASED ON UPSTREAM OBS.
PREVIOUS DISCUSSION...COLD AIR DAMMING REMAINS FIRMLY ENTRENCHED
E OF THE MTNS THIS MORNING. ONLY RELATIVE WARMTH TO BE FOUND
ACROSS THE CWFA IS IN THE CT RIVER VALLEY...WHERE READINGS ARE IN
THE MID 30S. THIS IS THE CRITICAL PART OF THE FORECAST...AS WEAK
LOW PRES AND SLUG OF PCPN LIFTS NEWD ALONG THE EAST COAST.
THRU THIS MORNING THERE IS NO REAL MECHANISM TO SCOUR OUT THE LLVL
COLD AIR. SO THE EXPECTATION IS THAT AREAS BELOW FREEZING WILL
REMAIN THAT WAY...PROBABLY INTO THE AFTERNOON. RECENT RAP AND
HRRR RUNS KEEP MUCH OF THE AREA BELOW FREEZING THRU 18Z. H8 TEMPS
ARE COOLING SLIGHTLY...BUT 06Z GYX SOUNDING CONFIRMS THAT WE STILL
HAVE A WARM NOSE OF +10 C AT 900 MB. AS THE COLUMN RE-SATURATES
AND PCPN BEGINS FALLING...FZRA IS REALLY THE ONLY SCENARIO FOR
MUCH OF THE AREA. THE CT RIVER VALLEY AND POSSIBLY THE IMMEDIATE
COASTLINE WILL SEE JUST RNFL WITH TEMPS ABOVE FREEZING. IN THE
FAR N AROUND JACKMAN...COLD AIR IS STILL DEEP ENOUGH FOR A MIX OF
PL OR SN AT TIMES. NAM12 ACTUALLY HAS A REALLY GOOD HANDLE ON
THERMAL PROFILE ATTM...SO BASED WX GRIDS OFF MODEL THICKNESS
VALUES.
FOR QPF A BLEND OF THE 23/00Z ECMWF AND NERFC WAS PREFERRED. THIS
HAD GENERALLY 0.25 INCHES QPF RUNNING FROM KCON THRU KLEW AND TO KAUG.
THE COAST WAS CLOSE TO 0.50 INCHES. USING THESE VALUES AND
ACCOUNTING FOR SOME LOSS TO RUNOFF AND GRADUAL SURFACE WARMING...ICE
ACCRETION VALUES OF AN ADDITIONAL 0.1 TO 0.25 INCHES IS POSSIBLE.
THE GREATEST THREAT FOR ADDITIONAL SIGNIFICANT ICE ACCUMULATION IS
JUST INLAND FROM THE COAST TO ABOUT A KLEW TO KAUG LINE.
ADDITIONALLY FZRA WILL BE LIKELY DURING THE MORNING
COMMUTE...WHICH WILL ADD TO THE HAZARD.
GIVEN THESE EXPECTATIONS HAVE ADJUSTED HEADLINES TO MATCH. HAVE
DROPPED WARNINGS ACROSS NH...AND CONVERTED COOS COUNTY TO A WINTER
WX ADVISORY. NRN CARROLL COUNTY WILL BE INCLUDED WITH FZRA
ADVISORY TO THE S. WILL ALLOW THE WRN NH ZONES TO EXPIRE MID
MORNING. WINTER STORM WARNINGS IN NRN ME MTNS WILL ALSO BE
DROPPED IN FAVOR OF WINTER WX ADVISORIES FOR COMBINATION OF SN AND
FZRA. ICE STORM WARNINGS WILL REMAIN AS IS. EVEN THOUGH SOME AREAS
MAY NOT SEE 0.5 INCHES OF ICE ACCRETION...CONFUSION OF DOWNGRADING
THE HEADLINE AS FZRA IMPACTS MORNING COMMUTE ARGUED FOR THE
CONTINUITY.
&&
.SHORT TERM /5 PM THIS AFTERNOON THROUGH 6 PM TUESDAY/...
S/WV TROF DROPPING THRU THE OHIO VALLEY WILL FINALLY BE THE
IMPETUS THAT PUSHES FRONTAL BOUNDARY THRU THE REGION. AS FLOW
BECOMES NW AND CAA COMMENCES WE WILL FINALLY MIX OUT THE LLVLS OF
THE ATMOSPHERE. GIVEN SUCH WARMTH ALOFT...THIS MAY ACTUALLY CAUSE
TEMPS TO JUMP UP SEVERAL DEGREES IN A SHORT AMOUNT OF TIME. THIS
IS THE MOST LIKELY TIME THAT HIGH TEMPS WILL BE REACHED.
CROSS BARRIER FLOW AND UPPER TROF SWINGING OVERHEAD WILL ALSO
SUPPORT SCT SHSN IN THE MTNS. SEASONABLY COLD AIR LURKING JUST
OVER THE INTERNATIONAL BORDER WILL ONCE AGAIN RETURN FOR THE AREA
TUE...WITH HIGHS REMAINING IN THE 20S.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
MODELS ARE FAIRLY SIMILAR FOR THE THE WEEK. HIGH PRESSURE WILL
BUILD OVER THE AREA TUESDAY AND WEDNESDAY AND MOVE EAST OF THE
AREA THURSDAY. LOW PRESSURE WILL TRAVEL NORTH OF NEW ENGLAND
THROUGH SOUTHERN CANADA THURSDAY AND FRIDAY. A COLD FRONT WILL
MOVE THROUGH MAINE AND NEW HAMPSHIRE LATE THURSDAY NIGHT. A WARM
FRONT WILL MOVE NORTH OF THE AREA FRIDAY OR SATURDAY FOLLOWED BY A
COLD FRONT SUNDAY OR MONDAY. THE MODELS DIFFER ON THE TIMING OF
THE SYSTEM FOR NEXT WEEKEND WITH THE ECMWF BEING SLOWER AND
TRACKING THE SURFACE LOW THROUGH MAINE VERSUS THE GFS TRACKING THE
LOW NORTH OF THE ST LAWRENCE RIVER.
&&
.AVIATION /15Z MONDAY THROUGH FRIDAY/...
SHORT TERM...LIFR AND IFR CONDITIONS WILL CONTINUE INTO THE EARLY
AFTERNOON. FZRA AND FZDZ WILL CONTINUE AS WELL. BY THE LATE
AFTERNOON NW WINDS WILL BEGIN SLOWLY CLEARING AND DRYING THE AREA
OUT FROM W TO E.
LONG TERM...EXPECT VFR THROUGH THE PERIOD.
&&
.MARINE...
SHORT TERM...MARGINAL SCA CONDITIONS WILL CONTINUE INTO THE EARLY
AFTERNOON. WINDS WILL REMAIN MOSTLY BELOW 25 KTS...BUT SEAS WILL
REMAIN NEAR 5 FT. CAA OVER THE WATERS TUE COULD BRINGS WINDS AND
SEAS BACK TO SCA THRESHOLDS.
LONG TERM...SMALL CRAFT CONDITIONS ARE POSSIBLE WEDNESDAY THROUGH FRIDAY.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...WINTER WEATHER ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
MEZ007>009.
ICE STORM WARNING UNTIL 4 PM EST THIS AFTERNOON FOR MEZ012>014-
019>022-024>028.
FREEZING RAIN ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
MEZ018-023.
NH...WINTER WEATHER ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
NHZ001-002.
FREEZING RAIN ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
NHZ004-006-008>010-013-014.
FREEZING RAIN ADVISORY UNTIL NOON EST TODAY FOR NHZ003-005-007.
MARINE...SMALL CRAFT ADVISORY UNTIL 5 AM EST TUESDAY FOR ANZ150-152-154.
&&
$$
SCHWIBS
AREA FORECAST DISCUSSION
NWS GRAY ME
702 AM EST MON DEC 23 2013
.SYNOPSIS...
A WAVE OF LOW PRESSURE WILL RIDE NORTHEAST ALONG A COLD FRONT
TODAY. THIS WILL SPREAD FREEZING RAIN AND A WINTRY MIX OF
PRECIPITATION INTO THE AREA ONCE AGAIN. THE COLD FRONT WILL
FINALLY MOVE OUT TO SEA LATE TODAY. HIGH PRESSURE AND COLDER AIR WILL
THEN BUILD OVER THE REGION FOR THE MIDWEEK PERIOD. LOW PRESSURE
WILL PASS NORTH OF THE AREA AND DRAG A TRAILING COLD FRONT ACROSS
THE REGION EARLY FRIDAY FOLLOWED BY HIGH PRESSURE FOR LATE FRIDAY
AND SATURDAY.
&&
.NEAR TERM /UNTIL 5 PM THIS AFTERNOON/...
659 AM...I MADE SOME MINOR ADJUSTMENTS TO 1ST PERIOD GRIDS TO
REFLECT CURRENT MESONET AS WELL AS RADAR TRENDS. ON THE WATERS...I
EXTENDED THE CURRENT SMALL CRAFT ADVISORY THROUGH LATE TONIGHT.
PREV DISC...
UPDATE...MADE A FEW MINOR CHANGES TO THE GRIDS TO ACCOUNT FOR
CURRENT OBSERVATIONAL TRENDS. HAVE ALSO DELAYED THE TIMING OF
CATEGORICAL POP UNTIL AFTER 12Z BASED ON UPSTREAM OBS.
PREVIOUS DISCUSSION...COLD AIR DAMMING REMAINS FIRMLY ENTRENCHED
E OF THE MTNS THIS MORNING. ONLY RELATIVE WARMTH TO BE FOUND
ACROSS THE CWFA IS IN THE CT RIVER VALLEY...WHERE READINGS ARE IN
THE MID 30S. THIS IS THE CRITICAL PART OF THE FORECAST...AS WEAK
LOW PRES AND SLUG OF PCPN LIFTS NEWD ALONG THE EAST COAST.
THRU THIS MORNING THERE IS NO REAL MECHANISM TO SCOUR OUT THE LLVL
COLD AIR. SO THE EXPECTATION IS THAT AREAS BELOW FREEZING WILL
REMAIN THAT WAY...PROBABLY INTO THE AFTERNOON. RECENT RAP AND
HRRR RUNS KEEP MUCH OF THE AREA BELOW FREEZING THRU 18Z. H8 TEMPS
ARE COOLING SLIGHTLY...BUT 06Z GYX SOUNDING CONFIRMS THAT WE STILL
HAVE A WARM NOSE OF +10 C AT 900 MB. AS THE COLUMN RE-SATURATES
AND PCPN BEGINS FALLING...FZRA IS REALLY THE ONLY SCENARIO FOR
MUCH OF THE AREA. THE CT RIVER VALLEY AND POSSIBLY THE IMMEDIATE
COASTLINE WILL SEE JUST RNFL WITH TEMPS ABOVE FREEZING. IN THE
FAR N AROUND JACKMAN...COLD AIR IS STILL DEEP ENOUGH FOR A MIX OF
PL OR SN AT TIMES. NAM12 ACTUALLY HAS A REALLY GOOD HANDLE ON
THERMAL PROFILE ATTM...SO BASED WX GRIDS OFF MODEL THICKNESS
VALUES.
FOR QPF A BLEND OF THE 23/00Z ECMWF AND NERFC WAS PREFERRED. THIS
HAD GENERALLY 0.25 INCHES QPF RUNNING FROM KCON THRU KLEW AND TO KAUG.
THE COAST WAS CLOSE TO 0.50 INCHES. USING THESE VALUES AND
ACCOUNTING FOR SOME LOSS TO RUNOFF AND GRADUAL SURFACE WARMING...ICE
ACCRETION VALUES OF AN ADDITIONAL 0.1 TO 0.25 INCHES IS POSSIBLE.
THE GREATEST THREAT FOR ADDITIONAL SIGNIFICANT ICE ACCUMULATION IS
JUST INLAND FROM THE COAST TO ABOUT A KLEW TO KAUG LINE.
ADDITIONALLY FZRA WILL BE LIKELY DURING THE MORNING
COMMUTE...WHICH WILL ADD TO THE HAZARD.
GIVEN THESE EXPECTATIONS HAVE ADJUSTED HEADLINES TO MATCH. HAVE
DROPPED WARNINGS ACROSS NH...AND CONVERTED COOS COUNTY TO A WINTER
WX ADVISORY. NRN CARROLL COUNTY WILL BE INCLUDED WITH FZRA
ADVISORY TO THE S. WILL ALLOW THE WRN NH ZONES TO EXPIRE MID
MORNING. WINTER STORM WARNINGS IN NRN ME MTNS WILL ALSO BE
DROPPED IN FAVOR OF WINTER WX ADVISORIES FOR COMBINATION OF SN AND
FZRA. ICE STORM WARNINGS WILL REMAIN AS IS. EVEN THOUGH SOME AREAS
MAY NOT SEE 0.5 INCHES OF ICE ACCRETION...CONFUSION OF DOWNGRADING
THE HEADLINE AS FZRA IMPACTS MORNING COMMUTE ARGUED FOR THE
CONTINUITY.
&&
.SHORT TERM /5 PM THIS AFTERNOON THROUGH 6 PM TUESDAY/...
S/WV TROF DROPPING THRU THE OHIO VALLEY WILL FINALLY BE THE
IMPETUS THAT PUSHES FRONTAL BOUNDARY THRU THE REGION. AS FLOW
BECOMES NW AND CAA COMMENCES WE WILL FINALLY MIX OUT THE LLVLS OF
THE ATMOSPHERE. GIVEN SUCH WARMTH ALOFT...THIS MAY ACTUALLY CAUSE
TEMPS TO JUMP UP SEVERAL DEGREES IN A SHORT AMOUNT OF TIME. THIS
IS THE MOST LIKELY TIME THAT HIGH TEMPS WILL BE REACHED.
CROSS BARRIER FLOW AND UPPER TROF SWINGING OVERHEAD WILL ALSO
SUPPORT SCT SHSN IN THE MTNS. SEASONABLY COLD AIR LURKING JUST
OVER THE INTERNATIONAL BORDER WILL ONCE AGAIN RETURN FOR THE AREA
TUE...WITH HIGHS REMAINING IN THE 20S.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
MODELS ARE FAIRLY SIMILAR FOR THE THE WEEK. HIGH PRESSURE WILL
BUILD OVER THE AREA TUESDAY AND WEDNESDAY AND MOVE EAST OF THE
AREA THURSDAY. LOW PRESSURE WILL TRAVEL NORTH OF NEW ENGLAND
THROUGH SOUTHERN CANADA THURSDAY AND FRIDAY. A COLD FRONT WILL
MOVE THROUGH MAINE AND NEW HAMPSHIRE LATE THURSDAY NIGHT. A WARM
FRONT WILL MOVE NORTH OF THE AREA FRIDAY OR SATURDAY FOLLOWED BY A
COLD FRONT SUNDAY OR MONDAY. THE MODELS DIFFER ON THE TIMING OF
THE SYSTEM FOR NEXT WEEKEND WITH THE ECMWF BEING SLOWER AND
TRACKING THE SURFACE LOW THROUGH MAINE VERSUS THE GFS TRACKING THE
LOW NORTH OF THE ST LAWRENCE RIVER.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
SHORT TERM...LIFR AND IFR CONDITIONS WILL CONTINUE INTO THE EARLY
AFTERNOON. FZRA AND FZDZ WILL CONTINUE AS WELL. BY THE LATE
AFTERNOON NW WINDS WILL BEGIN SLOWLY CLEARING AND DRYING THE AREA
OUT FROM W TO E.
LONG TERM...EXPECT VFR THROUGH THE PERIOD.
&&
.MARINE...
SHORT TERM...MARGINAL SCA CONDITIONS WILL CONTINUE INTO THE EARLY
AFTERNOON. WINDS WILL REMAIN MOSTLY BELOW 25 KTS...BUT SEAS WILL
REMAIN NEAR 5 FT. CAA OVER THE WATERS TUE COULD BRINGS WINDS AND
SEAS BACK TO SCA THRESHOLDS.
LONG TERM...SMALL CRAFT CONDITIONS ARE POSSIBLE WEDNESDAY THROUGH FRIDAY.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...WINTER WEATHER ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
MEZ007>009.
ICE STORM WARNING UNTIL NOON EST TODAY FOR MEZ012>014-019>022-
024>028.
FREEZING RAIN ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
MEZ018-023.
NH...WINTER WEATHER ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
NHZ001-002.
FREEZING RAIN ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
NHZ004-006-008>010-013-014.
FREEZING RAIN ADVISORY UNTIL NOON EST TODAY FOR NHZ003-005-007.
MARINE...SMALL CRAFT ADVISORY UNTIL 5 AM EST TUESDAY FOR ANZ150-152-154.
&&
$$
SCHWIBS
AREA FORECAST DISCUSSION...UPDATED
NWS GRAY ME
535 AM EST MON DEC 23 2013
.SYNOPSIS...
A WAVE OF LOW PRESSURE WILL RIDE NORTHEAST ALONG A COLD FRONT
TODAY. THIS WILL SPREAD FREEZING INTO THE AREA ONCE AGAIN. THE
COLD FRONT WILL FINALLY MOVE OUT TO SEA LATE TODAY. HIGH PRESSURE
WILL THEN BUILD OVER THE REGION TUESDAY AND WEDNESDAY. LOW
PRESSURE WILL PASS NORTH OF THE AREA AND DRAG A TRAILING COLD
FRONT ACROSS THE REGION EARLY FRIDAY FOLLOWED BY HIGH PRESSURE FOR
LATE FRIDAY AND SATURDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
UPDATE...MADE A FEW MINOR CHANGES TO THE GRIDS TO ACCOUNT FOR
CURRENT OBSERVATIONAL TRENDS. HAVE ALSO DELAYED THE TIMING OF
CATEGORICAL POP UNTIL AFTER 12Z BASED ON UPSTREAM OBS.
PREVIOUS DISCUSSION...COLD AIR DAMMING REMAINS FIRMLY ENTRENCHED
E OF THE MTNS THIS MORNING. ONLY RELATIVE WARMTH TO BE FOUND
ACROSS THE CWFA IS IN THE CT RIVER VALLEY...WHERE READINGS ARE IN
THE MID 30S. THIS IS THE CRITICAL PART OF THE FORECAST...AS WEAK
LOW PRES AND SLUG OF PCPN LIFTS NEWD ALONG THE EAST COAST.
THRU THIS MORNING THERE IS NO REAL MECHANISM TO SCOUR OUT THE LLVL
COLD AIR. SO THE EXPECTATION IS THAT AREAS BELOW FREEZING WILL
REMAIN THAT WAY...PROBABLY INTO THE AFTERNOON. RECENT RAP AND
HRRR RUNS KEEP MUCH OF THE AREA BELOW FREEZING THRU 18Z. H8 TEMPS
ARE COOLING SLIGHTLY...BUT 06Z GYX SOUNDING CONFIRMS THAT WE STILL
HAVE A WARM NOSE OF +10 C AT 900 MB. AS THE COLUMN RE-SATURATES
AND PCPN BEGINS FALLING...FZRA IS REALLY THE ONLY SCENARIO FOR
MUCH OF THE AREA. THE CT RIVER VALLEY AND POSSIBLY THE IMMEDIATE
COASTLINE WILL SEE JUST RNFL WITH TEMPS ABOVE FREEZING. IN THE
FAR N AROUND JACKMAN...COLD AIR IS STILL DEEP ENOUGH FOR A MIX OF
PL OR SN AT TIMES. NAM12 ACTUALLY HAS A REALLY GOOD HANDLE ON
THERMAL PROFILE ATTM...SO BASED WX GRIDS OFF MODEL THICKNESS
VALUES.
FOR QPF A BLEND OF THE 23/00Z ECMWF AND NERFC WAS PREFERRED. THIS
HAD GENERALLY 0.25 INCHES QPF RUNNING FROM KCON THRU KLEW AND TO KAUG.
THE COAST WAS CLOSE TO 0.50 INCHES. USING THESE VALUES AND
ACCOUNTING FOR SOME LOSS TO RUNOFF AND GRADUAL SURFACE WARMING...ICE
ACCRETION VALUES OF AN ADDITIONAL 0.1 TO 0.25 INCHES IS POSSIBLE.
THE GREATEST THREAT FOR ADDITIONAL SIGNIFICANT ICE ACCUMULATION IS
JUST INLAND FROM THE COAST TO ABOUT A KLEW TO KAUG LINE.
ADDITIONALLY FZRA WILL BE LIKELY DURING THE MORNING
COMMUTE...WHICH WILL ADD TO THE HAZARD.
GIVEN THESE EXPECTATIONS HAVE ADJUSTED HEADLINES TO MATCH. HAVE
DROPPED WARNINGS ACROSS NH...AND CONVERTED COOS COUNTY TO A WINTER
WX ADVISORY. NRN CARROLL COUNTY WILL BE INCLUDED WITH FZRA
ADVISORY TO THE S. WILL ALLOW THE WRN NH ZONES TO EXPIRE MID
MORNING. WINTER STORM WARNINGS IN NRN ME MTNS WILL ALSO BE
DROPPED IN FAVOR OF WINTER WX ADVISORIES FOR COMBINATION OF SN AND
FZRA. ICE STORM WARNINGS WILL REMAIN AS IS. EVEN THOUGH SOME AREAS
MAY NOT SEE 0.5 INCHES OF ICE ACCRETION...CONFUSION OF DOWNGRADING
THE HEADLINE AS FZRA IMPACTS MORNING COMMUTE ARGUED FOR THE
CONTINUITY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/...
S/WV TROF DROPPING THRU THE OHIO VALLEY WILL FINALLY BE THE
IMPETUS THAT PUSHES FRONTAL BOUNDARY THRU THE REGION. AS FLOW
BECOMES NW AND CAA COMMENCES WE WILL FINALLY MIX OUT THE LLVLS OF
THE ATMOSPHERE. GIVEN SUCH WARMTH ALOFT...THIS MAY ACTUALLY CAUSE
TEMPS TO JUMP UP SEVERAL DEGREES IN A SHORT AMOUNT OF TIME. THIS
IS THE MOST LIKELY TIME THAT HIGH TEMPS WILL BE REACHED.
CROSS BARRIER FLOW AND UPPER TROF SWINGING OVERHEAD WILL ALSO
SUPPORT SCT SHSN IN THE MTNS. SEASONABLY COLD AIR LURKING JUST
OVER THE INTERNATIONAL BORDER WILL ONCE AGAIN RETURN FOR THE AREA
TUE...WITH HIGHS REMAINING IN THE 20S.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
MODELS ARE FAIRLY SIMILAR FOR THE THE WEEK. HIGH PRESSURE WILL
BUILD OVER THE AREA TUESDAY AND WEDNESDAY AND MOVE EAST OF THE
AREA THURSDAY. LOW PRESSURE WILL TRAVEL NORTH OF NEW ENGLAND
THROUGH SOUTHERN CANADA THURSDAY AND FRIDAY. A COLD FRONT WILL
MOVE THROUGH MAINE AND NEW HAMPSHIRE LATE THURSDAY NIGHT. A WARM
FRONT WILL MOVE NORTH OF THE AREA FRIDAY OR SATURDAY FOLLOWED BY A
COLD FRONT SUNDAY OR MONDAY. THE MODELS DIFFER ON THE TIMING OF
THE SYSTEM FOR NEXT WEEKEND WITH THE ECMWF BEING SLOWER AND
TRACKING THE SURFACE LOW THROUGH MAINE VERSUS THE GFS TRACKING THE
LOW NORTH OF THE ST LAWRENCE RIVER.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
SHORT TERM...LIFR AND IFR CONDITIONS WILL CONTINUE INTO THE EARLY
AFTERNOON. FZRA AND FZDZ WILL CONTINUE AS WELL. BY THE LATE
AFTERNOON NW WINDS WILL BEGIN SLOWLY CLEARING AND DRYING THE AREA
OUT FROM W TO E.
LONG TERM...EXPECT VFR THROUGH THE PERIOD.
&&
.MARINE...
SHORT TERM...MARGINAL SCA CONDITIONS WILL CONTINUE INTO THE EARLY
AFTERNOON. WINDS WILL REMAIN MOSTLY BELOW 25 KTS...BUT SEAS WILL
REMAIN NEAR 5 FT. CAA OVER THE WATERS TUE COULD BRINGS WINDS AND
SEAS BACK TO SCA THRESHOLDS.
LONG TERM...SMALL CRAFT CONDITIONS ARE POSSIBLE WEDNESDAY THROUGH FRIDAY.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...WINTER WEATHER ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
MEZ007>009.
ICE STORM WARNING UNTIL NOON EST TODAY FOR MEZ012>014-019>022-
024>028.
FREEZING RAIN ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
MEZ018-023.
NH...WINTER WEATHER ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
NHZ001-002.
FREEZING RAIN ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
NHZ004-006-008>010-013-014.
FREEZING RAIN ADVISORY UNTIL NOON EST TODAY FOR NHZ003-005-007.
MARINE...SMALL CRAFT ADVISORY UNTIL 11 AM EST THIS MORNING FOR ANZ150-
152-154.
&&
$$
LEGRO/HAWLEY
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1019 AM EST MON DEC 23 2013
LATEST UPDATE...
UPDATE
.SYNOPSIS...
ISSUED AT 330 AM EST MON DEC 23 2013
SNOW SHOWERS ARE EXPECTED TO BE ON THE INCREASE TODAY...ESPECIALLY
FOR AREAS ACROSS THE SOUTHWEST CORNER OF LOWER MICHIGAN. THE SNOW
SHOWERS ARE EXPECTED TO BECOME LOCALLY HEAVY AND COULD BRING A FEW
INCHES OF SNOW TO SOME LOCAL AREAS. THE SNOW SHOWERS WILL CONTINUE
INTO THE EVENING HOURS BEFORE MOVING SOUTH AND WEST OF THE AREA
TOWARD DAYBREAK TUESDAY MORNING.
COLDER AIR WILL MOVE IN FOR TUESDAY ALONG WITH SOME POSSIBLE
SUNSHINE FOR A SHORT PERIOD OF TIME. THE AREA WILL SEE A COUPLE OF
WAVES OF LOW PRESSURE THEN MOVE IN FOR CHRISTMAS DAY AND ON
THURSDAY. THIS WILL BRING MORE SNOW ACCUMULATIONS TO THE
AREA...ESPECIALLY FOR AREAS NEAR THE LAKESHORE.
&&
.UPDATE...
ISSUED AT 1018 AM EST MON DEC 23 2013
WILL BE EXPANDING THE ADVISORY TO INCLUDE MUSKEGON AND KENT
COUNTIES. THE THREAT FOR HEAVY SNOW HAS DECREASED SOMEWHAT OVER VAN
BUREN AND KALAMAZOO...BUT WILL KEEP THEM IN THE ADVISORY.
RADAR INDICATES THE BEGINNINGS OF A DOMINANT SNOW BAND EXTENDING
SOUTHEAST THROUGH THE HOLLAND AREA. THIS IS CONSIDERABLY FARTHER
NORTH THAN PREVIOUS THINKING. RADAR RETURNS ARE STARTING TO SPREAD
TO THE NORTHWEST OVER LAKE MICHIGAN...SUGGESTING THAT THE DEPTH OF
THE BAND IS INCREASING WITH INVERSION HEIGHTS AHEAD OF THE UPPER
TROUGH APPROACHING FROM THE MIDWEST.
THIS BAND IS EXPECTED TO INTENSIFY AND WILL LIKELY UNDULATE. RADAR
ALREADY SUGGESTS A MESOLOW TRYING TO FORM WEST OF MUSKEGON. A
CONSENSUS OF SIMULATED REFLECTIVITY IN THE HIGH RESOLUTION MODELS
SUGGESTS THAT THE BAND WILL LIFT NORTH TOWARDS MUSKEGON AND KENT
COUNTY DURING THE COURSE OF THE DAY. A PARTICULARLY INTERESTING TIME
FRAME WILL BE EARLY TONIGHT WHEN THE HRRR AND DOWNSCALED NAM BRING A
PRONOUNCED MESOLOW ACROSS MUSKEGON AND KENT COUNTIES WITH A LIKELY
ENHANCED BURST OF SNOW.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 330 AM EST MON DEC 23 2013
THE MAIN CONCERN IN THE SHORT TERM IS THE POTENTIAL LOCALLY HEAVY
SNOW BAND THAT LOOKS LIKELY TO AFFECT THE SOUTHWEST CORNER OF THE
CWFA TODAY AND TONIGHT. WE WILL BE EXPANDING THE ADVISORY IN
COVERAGE TO INCLUDE OTTAWA AND BARRY COUNTIES. WE WILL ALSO BE
EXTENDING THE ADVISORY IN TIME TO GO THROUGH 12Z TUE. WE ARE
CONCERNED THAT MUSKEGON AND KENT COUNTIES MAY NEED TO BE INCLUDED IN
THE ADVISORY ALSO...HOWEVER WE ARE NOT QUITE CONFIDENT YET TO
INCLUDE THEM IN AT THIS TIME DUE TO UNCERTAINTY WITH THE MOVEMENT OF
THE NARROW BAND.
SNOW SHOWERS HAVE STARTED TO AFFECT THE SW CORNER OF THE CWFA
ALREADY THIS MORNING. THE SNOW SHOWERS ARE RESULTING FROM COLDER AIR
COMING ON THE NW FLOW IN PLACE. THIS NW FLOW IS ON THE SRN PERIPHERY
OF A LARGER SCALE SFC TROUGH THAT CURRENTLY IS ORIENTED FROM THE
STORM SYSTEM ACROSS THE NE U.S. ALL THE WAY TO MANITOBA. THE TROUGH
IS RESULTING FROM BOTH THE UPPER WAVE DIVING SE TOWARD THE AREA...
AND A CONTRIBUTION FROM THE GREAT LAKES.
WE EXPECT THE SNOW SHOWERS TO INTENSIFY DURING THE DAY TODAY. THE
SHORTWAVE DIVING IN FROM THE NW WILL HELP TO INCREASE INVERSION
HTS TO OVER 10K FEET AND CAUSE THE SFC TROUGH TO SHARPEN UP. THIS
WILL ENHANCE THE CONVERGENCE OVER PLENTY OF OVER LAKE INSTABILITY
WITH DELTA T/S SITTING AROUND THE MID TO UPPER TEENS. ANOTHER
FACTOR FOR HEAVIER SNOW AMOUNTS IS THE BEST CONVERGENCE OCCURS IN
THE FAVORED LAYER OF THE DGZ AROUND 2-4K FT ALOFT. WE EXPECT TO
SEE SNOW SHOWERS TO BECOME HEAVY ENOUGH TO SEE LOCAL SNOWFALL
RATES OF OVER AN INCH PER HOUR UNDER THE NARROW BAND.
WE EXPECT THE BAND TO GRADUALLY SHIFT NORTH THIS AFTERNOON RESULTING
FROM THE UPPER FLOW AHEAD OF THE WAVE. THE FLOW WILL SHIFT FROM THE
NW ORIENTATION TO A MORE WNW ORIENTATION. THIS WILL SHIFT THE
HEAVIEST SNOW BAND FROM THE CURRENT LOCATION TO AT LEAST A HOLLAND
TO HASTINGS CORRIDOR. SOME OF THE HIGHER RES MODELS ARE EVEN SHOWING
THE BAND GETTING INTO A GRAND HAVEN TO SRN KENT COUNTY LINE...AND
EVEN SOME ARE TAKING THIS TO A MUSKEGON TO GR LINE. THESE BANDS ARE
QUITE TRICKY TO NAIL DOWN...BUT WHERE THEY GO CAN CAUSE QUITE AN
IMPACT IN A SHORT TIME. OUR CONFIDENCE IS HIGH ENOUGH AT THIS TIME
TO ADD IN OTTAWA AND BARRY COUNTIES FOR NOW. THERE IS SOME TIME TO
WATCH THE EVOLUTION OF THE BAND AND EXPAND THE ADVISORY FURTHER
NORTH INTO KENT AND MUSKEGON COUNTIES IF NEEDED AS IT WOULD NOT
AFFECT THOSE AREAS UNTIL AT LEAST 21Z OR SO.
THE BAND WILL END UP AT ITS FARTHEST NORTH ORIENTATION BETWEEN
00-03Z BEFORE IT THEN SINKS BACK SOUTH AND THEN EXITS THE AREA
TOWARD 12Z TUE. THIS WILL OCCUR AS THE UPPER WAVE PASSES EAST OF THE
AREA TOWARD 12Z TUE. WE CAN NOT RULE OUT AMOUNTS REACHING WARNING
CRITERIA AT LOCATIONS THAT SEE THE BANDS LAST OVER A CERTAIN AREA
THE LONGEST LIKE ALLEGAN COUNTY AND NEAR HOLLAND. WE WILL STICK WITH
THE ADVISORY AND WATCH HOW SNOWFALL TRANSPIRES.
MOST OF THE SNOW SHOWERS SHOULD TRANSITION OFFSHORE BY TUE MORNING
AS THE FLOW BECOMES NNE BEHIND THE TROUGH PASSAGE. WE ACTUALLY
EXPECT AT LEAST SOME CLEARING WHICH WOULD ALLOW TEMPS TO FALL OFF
QUITE COLD AT INLAND LOCATIONS. WE COULD SEE SOME BELOW ZERO
READINGS UP TOWARD LEOTA IF SKIES CLEAR ENOUGH. SOME SUN WILL BE
FOUND ON TUE WITH THE SFC RIDGE MOVING OVERHEAD AND STRONG
SUBSIDENCE BUILDING IN BETWEEN THE TWO UPPER WAVES. SOME LIGHT SNOW
SHOWERS MAY MOVE INLAND ON TUE AS THE LOW LEVEL FLOW BECOMES WRLY
WITH THE RIDGE.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 330 AM EST MON DEC 23 2013
MORE ACCUMULATING LAKE EFFECT/ENHANCED SNOW IS EXPECTED STARTING
LATE CHRISTMAS EVE AND CONTINUING CHRISTMAS DAY AND THURSDAY. THIS
IS FUELED BY A SERIES OF SHORTWAVES ASSOCIATED WITH A 120 KT UPPER
LEVEL JET DIVING SE FROM WRN CANADA. TOTAL NEW SNOWFALL DURING THIS
48 HOUR PERIOD COULD EASILY EXCEED SIX INCHES WEST OF A CADILLAC TO
KALAMAZOO LINE.
THE FIRST BATCH OF SNOW FOR LATE CHRISTMAS EVE INTO CHRISTMAS
MORNING IS A COMBINATION OF WARM ADVECTION SNOW WITH SSW FLOW LAKE
ENHANCEMENT. SEVERAL INCHES OF ACCUMULATION ARE POSSIBLE ALONG THE
LK MI COAST NORTH OF HOLLAND DURING THIS TIME.
THEN A FAIRLY POTENT SHORTWAVE FOLLOWS IMMEDIATELY BEHIND THIS
STARTING LATE CHRISTMAS DAY AND LASTING INTO THURSDAY. MEAN FLOW
DURING THIS PERIOD IS WESTERLY BRINGING ADDITIONAL ACCUMULATIONS
ALONG AND WEST OF HIGHWAY 131. MORE LAKE EFFECT SNOW SHOWERS ARE
POSSIBLE THURSDAY NIGHT AND FRIDAY AS A FINAL NRN STREAM SHORTWAVE
COMES THROUGH BEFORE THE UPPER FLOW GOES BRIEFLY ZONAL.
SATURDAY CONTINUES TO LOOK LIKE A MILDER DAY AS H8 TEMPS ABOVE ZERO
ARRIVE FROM THE WEST AS A LOW MOVES EAST ACROSS LK SUPERIOR. THE
WARM UP SHOULD BE RATHER BRIEF HOWEVER AS MODELS SHOW MORE -20C H8
AIR SWEEPING IN ON SUNDAY OR SUNDAY NIGHT. THIS OUGHT TO GET THE
LAKE EFFECT CRANKED UP AGAIN.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 703 AM EST MON DEC 23 2013
THE MAIN FOCUS WILL BE ON A NARROW BAND OF HEAVY LAKE EFFECT SNOW
TODAY AND TONIGHT WHICH MAY OR MAY NOT IMPACT THE MKG AND GRR
TERMINALS.
CONFIDENCE IS LOW... BUT IT COULD BECOME ORIENTED FROM MKG TO GRR
LATE THIS AFTERNOON AND EVENING AND BRING SEVERAL HOURS OF
IFR/LIFR VSBYS IN MDT TO HVY SNOW. IT IS ALSO POSSIBLE THAT THE
BAND WILL EXTEND WELL EAST INTO THE LAN AREA ALTHOUGH IT PROBABLY
WOULD NOT BE AS INTENSE THERE.
THE WEST-EAST ORIENTED BAND SHOULD MOVE SOUTHWARD AFTER 06Z TONIGHT
AND BEGIN IMPACTING AZO/BTL/JXN WHILE SNOW ENDS AT MKG/GRR/LAN.
OUTSIDE OF THE POTENTIAL INTENSE BAND OF SNOW TODAY AND TONIGHT...
MVFR SHOULD BE THE PREDOMINATE FLIGHT CATEGORY WITH CIGS 1500-2500
FEET AND SCATTERED/OCNL LIGHT SNOW REDUCING VSBYS TO 3-5 MILES.
&&
.MARINE...
ISSUED AT 419 AM EST MON DEC 23 2013
WE HAVE ISSUED A SMALL CRAFT ADVISORY FOR THE SOUTHERN TWO MARINE
ZONES. WEST TO NORTHWEST WINDS WILL COME UP ENOUGH TODAY TO
REQUIRE A HEADLINE.
THE NEXT HEADLINE WILL COME ON TUESDAY NIGHT AND INTO CHRISTMAS DAY.
A SOLID SMALL CRAFT ADVISORY AND POSSIBLE GALE WILL OCCUR AHEAD OF
THE CLIPPER SYSTEM EXPECTED TO MOVE IN AT THAT TIME.
&&
.HYDROLOGY...
ISSUED AT 857 AM EST MON DEC 23 2013
ARCTIC AIR RETURNS TODAY AND RIVERS ARE EXPECTED TO LOCK BACK IN
PLACE WITH ICE OVER THE NEXT FEW DAYS. THIS SHOULD SERVE TO
STABILIZE LEVELS. RELATIVELY FLAT ICE ON RIVERS IS A SIGN WATER IS
FLOWING RELATIVELY SMOOTHLY BENEATH. TEMPERATURES WILL REMAIN
BELOW FREEZING...AND WILL RESULT IN CONTINUED ICE GROWTH ON RIVERS
IN SOUTHWEST LOWER MICHIGAN. UNDER THESE CONDITIONS THE THREAT FOR
ICE JAMS IS LOW.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL 7 AM EST TUESDAY FOR MIZ056-064-
071-072.
WINTER WEATHER ADVISORY UNTIL 7 AM EST TUESDAY FOR MIZ050-057-
065.
LM...SMALL CRAFT ADVISORY UNTIL 1 PM EST TUESDAY FOR LMZ844-845.
&&
$$
UPDATE...TJT
SYNOPSIS...NJJ
SHORT TERM...NJJ
LONG TERM...MEADE
AVIATION...MEADE
HYDROLOGY...WALTON
MARINE...NJJ
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
547 AM CST MON DEC 23 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 356 AM CST MON DEC 23 2013
LIGHT SNOW CONTINUES EARLY THIS MORNING FROM CENTRAL MN THROUGH THE
TWIN CITIES AND WEST CENTRAL WI UNDER AN UPPER LEVEL TROUGH.
ANIMATION OF THE KMPX RADAR INDICATES A LOW/MID LEVEL CIRCULATION
ACROSS CENTRAL MN... WHICH VERIFIES WELL WITH THE RAP AVERAGE
850-700MB HEIGHT FIELD. THE UPPER TROUGH AND LOW LEVEL CYCLONIC
CIRCULATION WILL DRIFT EVER SO SLOWLY TO THE SOUTHEAST THROUGH THIS
EVENING. THIS WILL MAINTAIN PLENTY OF CLOUDS AND LIGHT SNOW ACROSS
EASTERN MN AND WESTERN WI THROUGH THE DAY WITH THE LIGHT SNOW
DIMINISHING ACROSS WEST CENTRAL WI THIS EVENING. SNOW AMOUNTS TODAY
ARE IN THE TRACE TO 1 INCH CATEGORY FOR THE MN CWA WITH 1 TO 2
INCHES FOR WEST CENTRAL WI. SNOW AMOUNTS IN WEST CENTRAL WI TONIGHT
ARE LESS THAN A HALF INCH.
THE TEMPERATURE FORECAST FOR TODAY AND TONIGHT IS RATHER
PROBLEMATIC. ONE CONCERN TODAY IS HOW MUCH OF A REBOUND WE WILL HAVE
ACROSS THE WESTERN HALF OF MINNESOTA AS THE ARCTIC AIR CONTINUES TO
POUR IN WHILE EASTERN AREAS HAVE SOME INSULATION FROM THE CLOUDS.
JUST ABOUT EVERYBODY IN THE MN RIVER VALLEY EARLY THIS MORNING IS
CURRENTLY NEAR 10 BELOW. LOWS COULD EASILY REACH 15 BELOW TO 20
BELOW ZERO BY DAYBREAK. THE CURRENT THINKING IS THAT WE WILL ONLY
MAKE IF BACK TO THE 5 BELOW TO 10 BELOW RANGE IN THE WEST TODAY WITH
SINGLE DIGITS IN EASTERN MN WITH SOME TEENS IN OUR FAR EASTERN
COUNTIES IN WI. WITH THE ARCTIC HIGH REACHING OUR WESTERN MN
COUNTIES THIS EVENING...TEMPERATURES SHOULD CRATER FOR A 6 TO 8
HOUR PERIOD BEFORE RISING AFTER MIDNIGHT AS SOUTHERLY LOW LEVEL
FLOW DEVELOPS AHEAD OF AN APPROACHING CLIPPER. HENCE... LOWS
TONIGHT ARE A BIG CONCERN. THE GEM AND ECMWF ARE ON THE COLD SIDE
OF GUIDANCE WITH 20 BELOW TO 30 BELOW ZERO FOR MOST OF OUR MN CWA
WITH 10 BELOW TO 20 BELOW ZERO IN WI. THE AREA WHERE THE COLDEST
TEMPERATURES WILL LIKELY BE REACHED IS ACROSS CENTRAL MN WHERE
SEVERAL INCHES OF NEW SNOW HAS FALLEN AND THE SNOW DEPTH IS NEARLY
A FOOT. THEREFORE...WENT NEAR 25 BELOW ACROSS CENTRAL MN WITH 15
BELOW TO 20 BELOW ACROSS SOUTHERN MN WITH AROUND 10 BELOW IN THE
TWIN CITIES AS WEST CENTRAL WI. A NON-DIURNAL TEMPERATURE TREND
WAS INSERTED ACROSS WEST CENTRAL MN DURING THE OVERNIGHT HOURS.
THE COLD TEMPERATURES AND NORTHWEST WINDS OF 10 TO 20 MPH THROUGH
THIS EVENING CERTAINLY SUPPORT THE CURRENT WIND CHILL WARNING AND
WIND CHILL ADVISORY HEADLINES WITH NO CHANGES BEING MADE AT THIS
TIME.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 356 AM CST MON DEC 23 2013
NOT MUCH HAS CHANGED IN THE LONG TERM WITH THIS UPDATE. WE WILL
MAINTAIN NORTHWEST FLOW AS WE REMAIN WEDGED BETWEEN A MEAN ERN PAC
RIDGE AND ERN NOAM TROUGH.
TUESDAY STILL LOOKS TO FEATURE STRONG SOUTHERLY WINDS AND A QUICK
BURST OF SNOW AS THE STRONG WAVE CURRENTLY ROUNDING THE TOP OF THE
RIDGE OVER THE GULF OF ALASKA COMES SLIDING ACROSS THE AREA. MODEL
AGREEMENT REMAINS HIGH WITH THIS SNOW...WITH ONLY MINOR TIMING
DIFFERENCES EXISTING AT THIS POINT. ALL MODELS SHOW FAIRLY
WIDESPREAD 0.1 TO 0.2 INCH QPF AMOUNTS FALLING WITH THIS SYSTEM.
ONLY EXPECT SNOW RATIOS TO RANGE FROM 15-18:1 DURING THE HEAVIEST
SNOW AS COMBINATION OF STRONG WAA IN THE H85-H7 LAYER WILL LIMIT THE
DEPTH OF THE DENDRITIC GROWTH ZONE AND STRONG WINDS FROM THE SFC
THROUGH THE DEPTH OF THE CLOUD LAYER WILL HELP BREAK APART ANY
CRYSTALS THAT TRY TO GET TOO BIG. THESE RATIOS WITH THE EXPECTED QPF
WILL RESULT IN A GOOD 1.5 TO 3.5 INCHES OF SNOW AREA WIDE. NAM/GFS
CONTINUE TO SHOW MIXING RATIOS ON THE 295K SFC UP AROUND 2.5
G/KG...WHICH SUPPORTS THE CURRENTLY EXPECTED SNOWFALL AMOUNTS.
ALTHOUGH THESE AMOUNTS FALL BELOW THE 4 INCH BENCHMARK FOR A WINTER
WEATHER ADVY...THE FACT THAT THIS WILL BE A FAIRLY HEALTHY BURST OF
SNOW FOR ABOUT 4 HOURS DURING THE AFTERNOON/EVENING OF CHRISTMAS EVE
WHEN TRAVEL WILL BE HEAVIER ACROSS THE AREA...FUTURE SHIFTS WILL
HAVE TO WEIGH THE MERITS OF ISSUING AN ADVY BASED ON THE POTENTIAL
TRAVEL IMPACTS.
FOR CHRISTMAS DAY...ANOTHER STRONG UPPER WAVE WILL BE PASSING DOWN
THROUGH THE AREA. THE NAM IS SHOWING HEIGHT FALLS WITH THIS WAVE ON
THE ORDER OF 160M IN 12 HOURS...WITH A 5 UNIT PV ANOMALY COMING DOWN
AS WELL. ALL OF THIS POINTS TO ANOTHER BURST OF SNOW AS THIS COMES
DOWN...THOUGH IT WILL BE COMING DOWN IN THE DRY WAKE OF TUESDAYS
SYSTEM...AS THOSE SPEC HUMIDITIES THAT WILL BE UP AROUND 2.5 G/KG
TUESDAY WILL BE DOWN BETWEEN 0.5 AND 1 G/KG WEDNESDAY...HENCE WHY
QPF INDICATED BY THE MODELS IS SPOTTY AT BEST. THIS JUST LOOKS TO BE
ANOTHER SHOT AT SEEING A FAIRLY WIDESPREAD HALF INCH OF SNOW ON
LIQUID AMOUNTS THAT ARE A TRACE OR A HUNDREDTH OF AN INCH. AFTER
THIS WE MAY SEE REPEAT PERFORMANCES WITH SOME LIGHT SNOW/FLURRIES
AGAIN ON THURSDAY AND FRIDAY AS WE CONTINUE TO GET PEPPERED BY WEAK
UPPER WAVES IN THE NW FLOW. FOR SATURDAY...THE WRN RIDGE LOOKS TO
SHIFT FAR ENOUGH EAST TO PUSH THESE WAVES NORTH OF THE AREA...BUT
THE RETURN OF THE ARCTIC AIR SUNDAY WILL BRING ABOUT THE NEXT SHOT
AT A DUSTING.
TEMPERATURES WILL BE ON A BIT OF A ROLLER COASTER OVER THE NEXT
WEEK...THOUGH WE WILL BE BOUNCING BETWEEN NEAR NORMAL AND ABOUT 20
DEGREES BELOW NORMAL. WE WILL MAINTAIN OUR RESIDENCE IN THE ARCTIC
AIR THROUGH TONIGHT...BRIEFLY SHIFT OUT OF IT TUESDAY THROUGH
WEDNESDAY...RECEIVE A MORE GLANCING BLOW OF ARCTIC AIR WEDNESDAY
NIGHT THROUGH THURSDAY NIGHT...GET OUR WARMEST BREAK FROM THE ARCTIC
AIR FRIDAY AND SATURDAY...THEN SEE WHAT COULD BE OUR COLDEST BLAST
OF AIR YET FOR SATURDAY NIGHT INTO SUNDAY OF NEXT WEEKEND. FROM THE
WIND CHILL HEADLINE END OF THINGS...THE GLANCING BLOW OF ARCTIC AIR
WEDNESDAY NIGHT THROUGH THURSDAY NIGHT LOOKS TO BE JUST WARM ENOUGH
TO CEASE THE NEED FOR ANY WIND CHILL HEADLINES AFTER TUESDAY MORNING
UNTIL THE NEXT HEALTHY DOSE OF ARCTIC AIR RETURNS SUNDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 545 AM CST MON DEC 23 2013
A HODGEPODGE OF CEILING AND VISIBILITY CONDITIONS THIS MORNING
ACROSS EASTERN MN AND WESTERN WI AS AN UPPER LEVEL LOW OVERHEAD
DRIFTS SLOWLY SE. THE ARCTIC AIR SPILLING IN FROM THE WEST
NORTHWEST HAS AIDED IN HELPING CEILINGS RISE INTO THE VFR CATEGORY
FROM KSTC THROUGH KMSP EVEN THROUGH MVFR VSBYS IN -SN CONTINUE.
THESE TWO SITES SHOULD SEE IMPROVEMENT TO VFR VSBYS BY LATE IN THE
MORNING. KRNH AND KEAU WILL BE SLOWER TO IMPROVE SINCE THEY WILL
BE JUST ON THE EAST SIDE OF THE TROUGH AXIS ALOFT. IMPROVEMENT
FORECAST TO VFR BY LATE AFTERNOON/EVENING RESPECTIVELY. NOT TOO
MANY PROBLEMS FOR KAXN AND KRWF BUT THERE WILL BE BRISK NW WINDS
THIS MORNING WHICH MAY CAUSE SOME VSBY RESTRICTION IN BLSN AT
KRWF. ARCTIC HIGH MOVING IN TONIGHT WITH VFR CONDITIONS AND VERY
COLD TEMPERATURES.
KMSP...
MVFR VSBY IN -SN IMPROVING TO VFR 15Z-18Z. CEILING SHOULD STAY
AT OR ABOVE 035 THIS MORNING ALTHOUGH A BRIEF PERIOD OF MVFR CAN/T
BE RULED OUT. SCT CONDITIONS DEVELOPING THIS AFTERNOON. NORTHWEST
WINDS 12 KNOTS TODAY...BACKING TO WEST 5 KNOTS THIS EVENING AND SE
8 KNOTS TUESDAY MORNING. SNOW SPREADING IN TUESDAY AFTERNOON
BETWEEN 18Z-21Z AND CONTINUING THROUGH THE EVENING. SNOW
ACCUMULATION AROUND 3 INCHES LIKELY.
/OUTLOOK FOR KMSP/
TUE...VFR MRNG. MVFR/IFR WITH SN IN THE AFTN. WINDS S AT
10G20KTS.
WED...MVFR WITH -SN/BLSN POSSIBLE. WINDS W AT 15G25KTS.
THU...VFR. WINDS W AT 10KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WIND CHILL ADVISORY UNTIL NOON CST TUESDAY FOR MNZ042-043-
049>051-058-059-066>069-076-077-084-085-091>093.
WIND CHILL WARNING UNTIL NOON CST TUESDAY FOR MNZ041-047-048-
054>057-064-065-073>075-082-083.
WI...NONE.
&&
$$
SHORT TERM...RAH
LONG TERM...MPG
AVIATION...RAH
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1208 PM MST MON DEC 23 2013
.UPDATE...
ISSUED AT 1208 PM MST MON DEC 23 2013
ALLOWED WINTER WEATHER ADVISORIES FOR ALL BUT THE ELKHEAD AND PARK
RANGES TO EXPIRE AT NOON. AS PREVIOUSLY DISCUSSED...THE ELKHEAD
AND PARK RANGES HAVE BEEN UPGRADED TO A WINTER STORM WARNING WHICH
IS IN EFFECT THROUGH TUESDAY AFTERNOON. HOWEVER...ISSUED ANOTHER
SET OF WINTER WEATHER ADVISORIES FOR STEAMBOAT SPRINGS AND
SURROUNDING AREAS... THE FLAT TOPS...AND THE GORE RANGE AND NORTH
CENTRAL MOUNTAINS BEGINNING LATE TONIGHT AND CONTINUING THROUGH
TUESDAY AFTERNOON. A MORE DETAILED DISCUSSION FORTHCOMING WITH THE
AFTERNOON ISSUANCE.
UPDATE ISSUED AT 904 AM MST MON DEC 23 2013
SNOTEL DATA INDICATED SIGNIFICANT SNOWFALL OCCURRED OVER THE PAST
24 HOURS IN THE ELKHEAD AND GORE MOUNTAINS (ZONE 4). ACCUMULATIONS
RANGED FROM ROUGHLY 10 TO 18 INCHES ON AVERAGE WITH SOME HIGHER
AMOUNTS. SURROUNDING MOUNTAIN AREAS ABOVE 7500 FEET RECEIVED
CONSIDERABLY LESS SNOWFALL DURING THIS EVENT. LATEST RUC13 AND
NAM12 DATA SUGGESTED THAT SNOWFALL WILL CONTINUE OVER THE HIGHER
PEAKS OF THE ELKHEAD AND PARK MOUNTAINS THROUGH THE AFTERNOON
BEFORE INCREASING WITH THE NEXT SYSTEM WHICH WILL IMPACT THE AREA
TONIGHT AND TUESDAY AS DESCRIBED BELOW. GIVEN SIGNIFICANT AMOUNTS
ALREADY RECEIVED AND THE LACK OF ANY SUBSTANTIVE BREAK BETWEEN
THESE SYSTEMS OPTED TO UPGRADE THE ADVISORY FOR ZONE 4 TO A WINTER
STORM WARNING. THIS WARNING WILL CONTINUE THROUGH 6 PM MST
TUESDAY. MEANWHILE...THERE WILL BE AN END IN SNOWFALL FOR THE
OTHER ZONES IN THE THE ADVISORIES ALREADY IN PLACE AND PLAN TO LET
THOSE EXPIRE AT NOON. MEANWHILE...FOG NOT AS PREVALENT THIS
MORNING SO WILL BE REMOVING IT FROM TODAY/S FORECAST.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 414 AM MST MON DEC 23 2013
MODERATELY FAST NORTHWEST FLOW REMAINS IN PLACE OVER THE CENTRAL AND
NORTHERN ROCKIES...SQUEEZED BETWEEN A MID CONUS TROF AND RIDGING
ALONG THE LEFT COAST. WATER VAPOR IMAGERY AND REGIONAL PROFILER
NETWORK SHOWING THE BACK EDGE OF ONE WAVE EXITING THE HIGH PLAINS
WITH A MORE DEFINED KICKER SYSTEM JUST MOVING ONTO THE BRITISH
COLUMBIA COASTLINE. DERIVED SATELLITE IMAGERY SHOWING ANOTHER DECENT
PUSH OF MOISTURE INTO THE PACIFIC NORTHWEST COMING IN WITH THIS JET
MAX WITH PWAT RUNNING SOME 150 PERCENT OF NORMAL JUST UPSTREAM OF
SLC TO THE WASHINGTON COAST. WEB CAMS AND SURFACE OBS SHOW SNOW
CONTINUING ALONG THE PARK AND GORE RANGES DOWN TO STEAMBOAT SPRING
AND VAIL AREAS EARLY THIS MORNING. WILL BE KEEPING THE WINTER
WEATHER ADVISORY GOING TO NOON AS CURRENTLY ADVERTISED. WE SHOULD
SEE A DECREASING TREND IN COVERAGE OF THE PRECIPITATION THIS MORNING
AS LAPSE RATES RELAX WITH A TRANSITORY RIDGE SLIPPING OVERHEAD.
MOIST OROGRAPHICS WILL LIKELY KEEP LIGHT GOING OVER THE DIVIDE NORTH
OF VAIL PASS THROUGH THE DAY BUT ADDITIONAL AMOUNTS LOOK MINIMAL.
CLOUD COVER AND ENOUGH MIXING SEEMS TO HAVE THE PBL STIRRED UP
ENOUGH TO PREVENT THE FOG OF PREVIOUS NIGHTS SO FAR. HAVE KEPT THE
MENTION...BUT REDUCED TO PATCHY AS NOT CONVINCED IT WON/T TRY TO
REFORM BY SUNRISE...ESPECIALLY THE UINTA VALLEY. TEMPERATURES MAY
WARM A FEW DEGREES IN AREAS NORTH OF I-70 BUT FOR THE MOST PART HAVE
KEPT FORECAST BELOW GUIDANCE FOR HIGHS TODAY.
THETA SURFACES AT 300-310K SHOW A CONSTANT FEED OF MOISTURE
TODAY...FEEDING THE LIGHT OROGRAPHIC SHOWERS IN THE NORTHWEST
MOUNTAINS. LARGE SCALE ASCENT WILL BE INCREASING OVER OUR NORTHERN
CWA LATE THIS EVENING AS THE MAIN SYSTEM MOVES ACROSS NORTHERN
WYOMING AND MONTANA. THIS ASCENT WILL HELP FOCUS THE MOISTURE AND
TOP DOWN SATURATION WILL BE INCREASING THE SNOW THROUGH THE EARLY
MORNING HOURS NORTH OF INTERSTATE 70 WHERE UPGLIDE WITH BE THE
STRONGEST AND CONDENSATION DEFICITS THE LOWEST. BUFKIT PROFILES
INDICATE THE FAVORED TIME FOR PRECIPITATION IN THE NORTHERN VALLEYS
NEAR 12Z TUESDAY. THE UPGLIDE DECREASES QUICKLY THROUGH THE
AFTERNOON AS THE WAVE PASSES TO OUR NORTHEAST. THIS SHOULD LEAD TO A
NOTICEABLE DECREASE IN PRECIPITATION THROUGH THE DAY AS SNOW FOCUSES
MORE ON THE HIGHER NORTHWEST FACING SLOPES AS OROGRAPHICS DOMINATE
THE LIFT. THE FAST MOVEMENT AND LIMITED INSTABILITY WITH THIS WAVE
POINTS TOWARD SUB ADVISORY SNOWFALL ATTM WITH THE HIGHEST AMOUNTS
PINNED TO THE NORTHWEST DIVIDE. TEMPERATURES WILL STAY UP A TAD
OVERNIGHT AND CLOUDS SHOULD LIMIT DENSE FOG.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 414 AM MST MON DEC 23 2013
LATEST MODEL RUNS SHOW ECMWF AND GFS IN GOOD AGREEMENT FOR ENTIRE
LONG TERM FORECAST PERIOD. TUESDAY NIGHT INTO WEDNESDAY MORNING
WILL SEE LIGHT SNOW FINALLY ENDING FOR NORTHERN REGIONS WITH
NAM12/GFS/EC ALL IN AGREEMENT WITH THIS SCENARIO. AFTER THAT...A
LARGE RIDGE OF HIGH PRESSURE WILL BUILD IN WITH AXIS JUST OFF THE
WEST COAST. THIS WILL KEEP NWRLY FLOW IN THE FORECAST UNTIL FRIDAY
WHEN AN AREA OF LOW PRESSURE APPROACHES NRN CALIFORNIA CAUSING
RIDGE TO SHIFT EAST AND START BREAKING DOWN.
BY NOON FRIDAY...ZONAL FLOW SETS UP AS A TROUGH MOVES OVER THE NRN
ROCKIES AND PLAINS WHILE THE CLOSED LOW CONTINUES TO APPROACH
CALIFORNIA COAST. PRESENTLY...MODELS KEEP PRECIP ASSOD WITH TROUGH
WELL TO OUR N UNTIL SUNDAY AFTN WHEN NRN MTNS MAY SEE SOME LIGHT
SNOWSHOWERS. AS FAR AS THE LOW PRESSURE TO THE WEST...BOTH GFS AND
EC SHOW REX BLOCK SETTING UP SUNDAY ONWARDS. EVEN THOUGH THE LOW
REMAINS ANCHORED OFF THE CALIFORNIA COAST...MOISTURE WILL CAUSE
SOME CLOUDS OVER THE DESERT SW WILL VERY LITTLE PRECIP EXPECTED
ATTM. THIS MAY CHANGE AS WE MOVE AHEAD IN TIME HOWEVER.
ALL IN ALL...THE NEXT 5 DAYS WILL BE RATHER QUIET WITH SOME CLOUDS
MOVING OVERHEAD FROM TIME TO TIME WITH LITTLE CHANGE FROM DAY TO DAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1001 AM MST MON DEC 23 2013
SNOW WILL CONTINUE OVER THE NORTHERN COLORADO MOUNTAINS THROUGH
THE NEXT 24 HOURS RESULTING IN WIDESPREAD OBSCURATION. MVFR CIGS
AND VSBY SHOULD LIFT TO VFR AT KSBS EARLY THIS AFTERNOON...BUT
WILL FALL AGAIN TONIGHT AS SNOW INCREASES AHEAD OF ANOTHER SYSTEM
DROPPING DOWN FROM THE NORTHWEST. AS THIS SYSTEM SETS IN KCAG...
KEEO...KEGE...AND KASE WILL BE IMPACTED WITH MVFR AND POSSIBLY IFR
CONDITIONS AFTER 06Z AND 18Z TUES. ELSEWHERE...THE LOWER VALLEYS
MAY SEE MVFR CIGS/VSBY IN FOG TONIGHT AND TUESDAY MORNING WITH
BEST CHANCES AT KVEL AND KCNY. VFR CONDITIONS WILL PREVAIL OUTSIDE
OF THE AREAS MENTIONED ABOVE THROUGH THE NEXT 24 HOURS.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...WINTER STORM WARNING UNTIL 6 PM MST TUESDAY COZ004.
WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 6 PM MST
TUESDAY COZ005.
WINTER WEATHER ADVISORY FROM 3 AM TO 6 PM MST TUESDAY ABOVE 8000
FEET FOR COZ010.
WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 6 PM MST
TUESDAY COZ013.
UT...NONE.
&&
$$
UPDATE...NL
SHORT TERM...15
LONG TERM...TGR
AVIATION...NL
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1001 AM MST MON DEC 23 2013
.UPDATE...
ISSUED AT 904 AM MST MON DEC 23 2013
SNOTEL DATA INDICATED SIGNIFICANT SNOWFALL OCCURRED OVER THE PAST
24 HOURS IN THE ELKHEAD AND GORE MOUNTAINS (ZONE 4). ACCUMULATIONS
RANGED FROM ROUGHLY 10 TO 18 INCHES ON AVERAGE WITH SOME HIGHER
AMOUNTS. SURROUNDING MOUNTAIN AREAS ABOVE 7500 FEET RECEIVED
CONSIDERABLY LESS SNOWFALL DURING THIS EVENT. LATEST RUC13 AND
NAM12 DATA SUGGESTED THAT SNOWFALL WILL CONTINUE OVER THE HIGHER
PEAKS OF THE ELKHEAD AND PARK MOUNTAINS THROUGH THE AFTERNOON
BEFORE INCREASING WITH THE NEXT SYSTEM WHICH WILL IMPACT THE AREA
TONIGHT AND TUESDAY AS DESCRIBED BELOW. GIVEN SIGNIFICANT AMOUNTS
ALREADY RECEIVED AND THE LACK OF ANY SUBSTANTIVE BREAK BETWEEN
THESE SYSTEMS OPTED TO UPGRADE THE ADVISORY FOR ZONE 4 TO A WINTER
STORM WARNING. THIS WARNING WILL CONTINUE THROUGH 6 PM MST
TUESDAY. MEANWHILE...THERE WILL BE AN END IN SNOWFALL FOR THE
OTHER ZONES IN THE THE ADVISORIES ALREADY IN PLACE AND PLAN TO LET
THOSE EXPIRE AT NOON. MEANWHILE...FOG NOT AS PREVALENT THIS
MORNING SO WILL BE REMOVING IT FROM TODAY/S FORECAST.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 414 AM MST MON DEC 23 2013
MODERATELY FAST NORTHWEST FLOW REMAINS IN PLACE OVER THE CENTRAL AND
NORTHERN ROCKIES...SQUEEZED BETWEEN A MID CONUS TROF AND RIDGING
ALONG THE LEFT COAST. WATER VAPOR IMAGERY AND REGIONAL PROFILER
NETWORK SHOWING THE BACK EDGE OF ONE WAVE EXITING THE HIGH PLAINS
WITH A MORE DEFINED KICKER SYSTEM JUST MOVING ONTO THE BRITISH
COLUMBIA COASTLINE. DERIVED SATELLITE IMAGERY SHOWING ANOTHER DECENT
PUSH OF MOISTURE INTO THE PACIFIC NORTHWEST COMING IN WITH THIS JET
MAX WITH PWAT RUNNING SOME 150 PERCENT OF NORMAL JUST UPSTREAM OF
SLC TO THE WASHINGTON COAST. WEB CAMS AND SURFACE OBS SHOW SNOW
CONTINUING ALONG THE PARK AND GORE RANGES DOWN TO STEAMBOAT SPRING
AND VAIL AREAS EARLY THIS MORNING. WILL BE KEEPING THE WINTER
WEATHER ADVISORY GOING TO NOON AS CURRENTLY ADVERTISED. WE SHOULD
SEE A DECREASING TREND IN COVERAGE OF THE PRECIPITATION THIS MORNING
AS LAPSE RATES RELAX WITH A TRANSITORY RIDGE SLIPPING OVERHEAD.
MOIST OROGRAPHICS WILL LIKELY KEEP LIGHT GOING OVER THE DIVIDE NORTH
OF VAIL PASS THROUGH THE DAY BUT ADDITIONAL AMOUNTS LOOK MINIMAL.
CLOUD COVER AND ENOUGH MIXING SEEMS TO HAVE THE PBL STIRRED UP
ENOUGH TO PREVENT THE FOG OF PREVIOUS NIGHTS SO FAR. HAVE KEPT THE
MENTION...BUT REDUCED TO PATCHY AS NOT CONVINCED IT WON/T TRY TO
REFORM BY SUNRISE...ESPECIALLY THE UINTA VALLEY. TEMPERATURES MAY
WARM A FEW DEGREES IN AREAS NORTH OF I-70 BUT FOR THE MOST PART HAVE
KEPT FORECAST BELOW GUIDANCE FOR HIGHS TODAY.
THETA SURFACES AT 300-310K SHOW A CONSTANT FEED OF MOISTURE
TODAY...FEEDING THE LIGHT OROGRAPHIC SHOWERS IN THE NORTHWEST
MOUNTAINS. LARGE SCALE ASCENT WILL BE INCREASING OVER OUR NORTHERN
CWA LATE THIS EVENING AS THE MAIN SYSTEM MOVES ACROSS NORTHERN
WYOMING AND MONTANA. THIS ASCENT WILL HELP FOCUS THE MOISTURE AND
TOP DOWN SATURATION WILL BE INCREASING THE SNOW THROUGH THE EARLY
MORNING HOURS NORTH OF INTERSTATE 70 WHERE UPGLIDE WITH BE THE
STRONGEST AND CONDENSATION DEFICITS THE LOWEST. BUFKIT PROFILES
INDICATE THE FAVORED TIME FOR PRECIPITATION IN THE NORTHERN VALLEYS
NEAR 12Z TUESDAY. THE UPGLIDE DECREASES QUICKLY THROUGH THE
AFTERNOON AS THE WAVE PASSES TO OUR NORTHEAST. THIS SHOULD LEAD TO A
NOTICEABLE DECREASE IN PRECIPITATION THROUGH THE DAY AS SNOW FOCUSES
MORE ON THE HIGHER NORTHWEST FACING SLOPES AS OROGRAPHICS DOMINATE
THE LIFT. THE FAST MOVEMENT AND LIMITED INSTABILITY WITH THIS WAVE
POINTS TOWARD SUB ADVISORY SNOWFALL ATTM WITH THE HIGHEST AMOUNTS
PINNED TO THE NORTHWEST DIVIDE. TEMPERATURES WILL STAY UP A TAD
OVERNIGHT AND CLOUDS SHOULD LIMIT DENSE FOG.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 414 AM MST MON DEC 23 2013
LATEST MODEL RUNS SHOW ECMWF AND GFS IN GOOD AGREEMENT FOR ENTIRE
LONG TERM FORECAST PERIOD. TUESDAY NIGHT INTO WEDNESDAY MORNING
WILL SEE LIGHT SNOW FINALLY ENDING FOR NORTHERN REGIONS WITH
NAM12/GFS/EC ALL IN AGREEMENT WITH THIS SCENARIO. AFTER THAT...A
LARGE RIDGE OF HIGH PRESSURE WILL BUILD IN WITH AXIS JUST OFF THE
WEST COAST. THIS WILL KEEP NWRLY FLOW IN THE FORECAST UNTIL FRIDAY
WHEN AN AREA OF LOW PRESSURE APPROACHES NRN CALIFORNIA CAUSING
RIDGE TO SHIFT EAST AND START BREAKING DOWN.
BY NOON FRIDAY...ZONAL FLOW SETS UP AS A TROUGH MOVES OVER THE NRN
ROCKIES AND PLAINS WHILE THE CLOSED LOW CONTINUES TO APPROACH
CALIFORNIA COAST. PRESENTLY...MODELS KEEP PRECIP ASSOD WITH TROUGH
WELL TO OUR N UNTIL SUNDAY AFTN WHEN NRN MTNS MAY SEE SOME LIGHT
SNOWSHOWERS. AS FAR AS THE LOW PRESSURE TO THE WEST...BOTH GFS AND
EC SHOW REX BLOCK SETTING UP SUNDAY ONWARDS. EVEN THOUGH THE LOW
REMAINS ANCHORED OFF THE CALIFORNIA COAST...MOISTURE WILL CAUSE
SOME CLOUDS OVER THE DESERT SW WILL VERY LITTLE PRECIP EXPECTED
ATTM. THIS MAY CHANGE AS WE MOVE AHEAD IN TIME HOWEVER.
ALL IN ALL...THE NEXT 5 DAYS WILL BE RATHER QUIET WITH SOME CLOUDS
MOVING OVERHEAD FROM TIME TO TIME WITH LITTLE CHANGE FROM DAY TO DAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1001 AM MST MON DEC 23 2013
SNOW WILL CONTINUE OVER THE NORTHERN COLORADO MOUNTAINS THROUGH
THE NEXT 24 HOURS RESULTING IN WIDESPREAD OBSCURATION. MVFR CIGS
AND VSBY SHOULD LIFT TO VFR AT KSBS EARLY THIS AFTERNOON...BUT
WILL FALL AGAIN TONIGHT AS SNOW INCREASES AHEAD OF ANOTHER SYSTEM
DROPPING DOWN FROM THE NORTHWEST. AS THIS SYSTEM SETS IN KCAG...
KEEO...KEGE...AND KASE WILL BE IMPACTED WITH MVFR AND POSSIBLY IFR
CONDITIONS AFTER 06Z AND 18Z TUES. ELSEWHERE...THE LOWER VALLEYS
MAY SEE MVFR CIGS/VSBY IN FOG TONIGHT AND TUESDAY MORNING WITH
BEST CHANCES AT KVEL AND KCNY. VFR CONDITIONS WILL PREVAIL OUTSIDE
OF THE AREAS MENTIONED ABOVE THROUGH THE NEXT 24 HOURS.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...WINTER WEATHER ADVISORY UNTIL NOON MST TODAY ABOVE 7500 FEET FOR
COZ008-010-013.
WINTER STORM WARNING UNTIL 6 PM MST TUESDAY ABOVE 7500 FEET FOR
COZ004.
WINTER WEATHER ADVISORY UNTIL NOON MST TODAY COZ005.
UT...NONE.
&&
$$
UPDATE...NL
SHORT TERM...15
LONG TERM...TGR
AVIATION...NL
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
904 AM MST MON DEC 23 2013
.UPDATE...
ISSUED AT 904 AM MST MON DEC 23 2013
SNOTEL DATA INDICATED SIGNIFICANT SNOWFALL OCCURRED OVER THE PAST
24 HOURS IN THE ELKHEAD AND GORE MOUNTAINS (ZONE 4). ACCUMULATIONS
RANGED FROM ROUGHLY 10 TO 18 INCHES ON AVERAGE WITH SOME HIGHER
AMOUNTS. SURROUNDING MOUNTAIN AREAS ABOVE 7500 FEET RECEIVED
CONSIDERABLY LESS SNOWFALL DURING THIS EVENT. LATEST RUC13 AND
NAM12 DATA SUGGESTED THAT SNOWFALL WILL CONTINUE OVER THE HIGHER
PEAKS OF THE ELKHEAD AND PARK MOUNTAINS THROUGH THE AFTERNOON
BEFORE INCREASING WITH THE NEXT SYSTEM WHICH WILL IMPACT THE AREA
TONIGHT AND TUESDAY AS DESCRIBED BELOW. GIVEN SIGNIFICANT AMOUNTS
ALREADY RECEIVED AND THE LACK OF ANY SUBSTANTIVE BREAK BETWEEN
THESE SYSTEMS OPTED TO UPGRADE THE ADVISORY FOR ZONE 4 TO A WINTER
STORM WARNING. THIS WARNING WILL CONTINUE THROUGH 6 PM MST
TUESDAY. MEANWHILE...THERE WILL BE AN END IN SNOWFALL FOR THE
OTHER ZONES IN THE THE ADVISORIES ALREADY IN PLACE AND PLAN TO LET
THOSE EXPIRE AT NOON. MEANWHILE...FOG NOT AS PREVALENT THIS
MORNING SO WILL BE REMOVING IT FROM TODAY/S FORECAST.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 414 AM MST MON DEC 23 2013
MODERATELY FAST NORTHWEST FLOW REMAINS IN PLACE OVER THE CENTRAL AND
NORTHERN ROCKIES...SQUEEZED BETWEEN A MID CONUS TROF AND RIDGING
ALONG THE LEFT COAST. WATER VAPOR IMAGERY AND REGIONAL PROFILER
NETWORK SHOWING THE BACK EDGE OF ONE WAVE EXITING THE HIGH PLAINS
WITH A MORE DEFINED KICKER SYSTEM JUST MOVING ONTO THE BRITISH
COLUMBIA COASTLINE. DERIVED SATELLITE IMAGERY SHOWING ANOTHER DECENT
PUSH OF MOISTURE INTO THE PACIFIC NORTHWEST COMING IN WITH THIS JET
MAX WITH PWAT RUNNING SOME 150 PERCENT OF NORMAL JUST UPSTREAM OF
SLC TO THE WASHINGTON COAST. WEB CAMS AND SURFACE OBS SHOW SNOW
CONTINUING ALONG THE PARK AND GORE RANGES DOWN TO STEAMBOAT SPRING
AND VAIL AREAS EARLY THIS MORNING. WILL BE KEEPING THE WINTER
WEATHER ADVISORY GOING TO NOON AS CURRENTLY ADVERTISED. WE SHOULD
SEE A DECREASING TREND IN COVERAGE OF THE PRECIPITATION THIS MORNING
AS LAPSE RATES RELAX WITH A TRANSITORY RIDGE SLIPPING OVERHEAD.
MOIST OROGRAPHICS WILL LIKELY KEEP LIGHT GOING OVER THE DIVIDE NORTH
OF VAIL PASS THROUGH THE DAY BUT ADDITIONAL AMOUNTS LOOK MINIMAL.
CLOUD COVER AND ENOUGH MIXING SEEMS TO HAVE THE PBL STIRRED UP
ENOUGH TO PREVENT THE FOG OF PREVIOUS NIGHTS SO FAR. HAVE KEPT THE
MENTION...BUT REDUCED TO PATCHY AS NOT CONVINCED IT WON/T TRY TO
REFORM BY SUNRISE...ESPECIALLY THE UINTA VALLEY. TEMPERATURES MAY
WARM A FEW DEGREES IN AREAS NORTH OF I-70 BUT FOR THE MOST PART HAVE
KEPT FORECAST BELOW GUIDANCE FOR HIGHS TODAY.
THETA SURFACES AT 300-310K SHOW A CONSTANT FEED OF MOISTURE
TODAY...FEEDING THE LIGHT OROGRAPHIC SHOWERS IN THE NORTHWEST
MOUNTAINS. LARGE SCALE ASCENT WILL BE INCREASING OVER OUR NORTHERN
CWA LATE THIS EVENING AS THE MAIN SYSTEM MOVES ACROSS NORTHERN
WYOMING AND MONTANA. THIS ASCENT WILL HELP FOCUS THE MOISTURE AND
TOP DOWN SATURATION WILL BE INCREASING THE SNOW THROUGH THE EARLY
MORNING HOURS NORTH OF INTERSTATE 70 WHERE UPGLIDE WITH BE THE
STRONGEST AND CONDENSATION DEFICITS THE LOWEST. BUFKIT PROFILES
INDICATE THE FAVORED TIME FOR PRECIPITATION IN THE NORTHERN VALLEYS
NEAR 12Z TUESDAY. THE UPGLIDE DECREASES QUICKLY THROUGH THE
AFTERNOON AS THE WAVE PASSES TO OUR NORTHEAST. THIS SHOULD LEAD TO A
NOTICEABLE DECREASE IN PRECIPITATION THROUGH THE DAY AS SNOW FOCUSES
MORE ON THE HIGHER NORTHWEST FACING SLOPES AS OROGRAPHICS DOMINATE
THE LIFT. THE FAST MOVEMENT AND LIMITED INSTABILITY WITH THIS WAVE
POINTS TOWARD SUB ADVISORY SNOWFALL ATTM WITH THE HIGHEST AMOUNTS
PINNED TO THE NORTHWEST DIVIDE. TEMPERATURES WILL STAY UP A TAD
OVERNIGHT AND CLOUDS SHOULD LIMIT DENSE FOG.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 414 AM MST MON DEC 23 2013
LATEST MODEL RUNS SHOW ECMWF AND GFS IN GOOD AGREEMENT FOR ENTIRE
LONG TERM FORECAST PERIOD. TUESDAY NIGHT INTO WEDNESDAY MORNING
WILL SEE LIGHT SNOW FINALLY ENDING FOR NORTHERN REGIONS WITH
NAM12/GFS/EC ALL IN AGREEMENT WITH THIS SCENARIO. AFTER THAT...A
LARGE RIDGE OF HIGH PRESSURE WILL BUILD IN WITH AXIS JUST OFF THE
WEST COAST. THIS WILL KEEP NWRLY FLOW IN THE FORECAST UNTIL FRIDAY
WHEN AN AREA OF LOW PRESSURE APPROACHES NRN CALIFORNIA CAUSING
RIDGE TO SHIFT EAST AND START BREAKING DOWN.
BY NOON FRIDAY...ZONAL FLOW SETS UP AS A TROUGH MOVES OVER THE NRN
ROCKIES AND PLAINS WHILE THE CLOSED LOW CONTINUES TO APPROACH
CALIFORNIA COAST. PRESENTLY...MODELS KEEP PRECIP ASSOD WITH TROUGH
WELL TO OUR N UNTIL SUNDAY AFTN WHEN NRN MTNS MAY SEE SOME LIGHT
SNOWSHOWERS. AS FAR AS THE LOW PRESSURE TO THE WEST...BOTH GFS AND
EC SHOW REX BLOCK SETTING UP SUNDAY ONWARDS. EVEN THOUGH THE LOW
REMAINS ANCHORED OFF THE CALIFORNIA COAST...MOISTURE WILL CAUSE
SOME CLOUDS OVER THE DESERT SW WILL VERY LITTLE PRECIP EXPECTED
ATTM. THIS MAY CHANGE AS WE MOVE AHEAD IN TIME HOWEVER.
ALL IN ALL...THE NEXT 5 DAYS WILL BE RATHER QUIET WITH SOME CLOUDS
MOVING OVERHEAD FROM TIME TO TIME WITH LITTLE CHANGE FROM DAY TO DAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 414 AM MST MON DEC 23 2013
SNOWFALL CONTINUES FOR THE NORTHERN COLORADO MOUNTAINS BUT
SHOULD LIGHTEN UP AFTER 18Z. OCCNL IFR AND LOWER VIS AND CIGS WILL
CONTINUE THROUGH THAT TIME FOR KSBS AND KHDN. MTN OBSCURATIONS
WILL ALSO CONTINUE.
FOG MUCH LESS WIDESPREAD THAN 24 HOURS AGO INCLUDING WITH VFR
CONDITIONS AT KVEL AND KGJT. KCNY IS BEGINNING TO SEE VSBYS LOW TO
IFR/MVFR AS FOG ROLLS IN AND OUT AND THIS TREND LIKELY TO CONTINUE
THROUGH THE MORNING. SUNRISE SURPRISE STILL A POSSIBILITY FOR
KVEL...KGJT AND KEGE BUT WILL HOLD OFF ANY MENTION FOR NOW AND
KEEP VCFG IN TAFS. IF FOG DOES FORM...EXPECT IT WILL NOT DROP VIS
TOO LOW...3 TO 4SM...BEFORE BURNING OFF AFTER 17Z OR SO.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...WINTER WEATHER ADVISORY UNTIL NOON MST TODAY ABOVE 7500 FEET FOR
COZ008-010-013.
WINTER STORM WARNING UNTIL 6 PM MST TUESDAY ABOVE 7500 FEET FOR
COZ004.
WINTER WEATHER ADVISORY UNTIL NOON MST TODAY COZ005.
UT...NONE.
&&
$$
UPDATE...NL
SHORT TERM...15
LONG TERM...TGR
AVIATION...TGR
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
345 PM EST MON DEC 23 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 343 PM EST MON DEC 23 2013
LATEST WV SATELLITE IMAGERY AND RUC ANALYSIS SHOWS BROAD 5H TROUGH
SLOWLY PUSHING E ACROSS THE WRN GREAT LAKES THIS AFTERNOON. WEAK
850-500MB Q-VECTOR CONVERGENCE ASSOC WITH THIS TROUGH OVER LAKE
SUPERIOR WILL TRANSITION TO Q-VECTOR DIVERGENCE THIS EVENING. VIS
IMAGERY SHOWS NE WIND PARALLEL LAKE EFFECT SNOW BANDS ACROSS LAKE
SUPERIOR IMPACTING MAINLY FAR WESTERN AND NORTH CENTRAL UPPER MI. A
FEW OF THE MORE INTENSE BANDS HAVE PRODUCED PERIODS OF MODERATE
SNOW. LES HAS BEEN VERY FLUFFY WITH SNOW RATIOS 40-50/1.
MAIN FORECAST CONCERN IS CONTINUING LES EVENT FOR FAR WESTERN AND
NORTH CENTRAL COUNTIES INTO THIS EVENING AND THEN DIMINISHING LES
OVERNIGHT INTO TUE MORNING. EXPECT ADDITIONAL SNOWFALL AMOUNTS OF 2
TO 5 INCHES THROUGH THIS EVENING. BEST LOW-LVL CONVERGENCE SUGGESTS
MORE INTENSE LES BANDS AND THUS GREATEST SNOW AMOUNTS WILL BE OVER
ERN HALF OF MQT COUNTY INTO PERHAPS WRN ALGER COUNTY. GIVEN
EXPECTATION OF CONTINUING LES ACCUMULATION INTO AT LEAST THE EVENING
HRS WILL CONTINUE ADVISORIES FOR GOGEBIC-ONTONAGON AND MQT-BARAGA
INTO THE EARLY OVERNIGHT.
LES SHOULD GENERALLY BE WINDING DOWN BY LATE EVENING INTO OVERNIGHT
HRS WITH Q-VECT DIVERGENCE ACROSS THE AREA AND WEAKENING WIND
FIELDS. LOW-LVL CONVERGENCE MAY STRENGTHEN DUE TO WEAKENING WINDS
AND DEVELOPING LAND BREEZES TO ALLOW MORE LOCALLY INTENSE LES BANDS
TO FORM AND PERHAPS EVEN A MESOLOW OR TWO OFF THE PORCUPINE
MOUNTAINS AND OVER MQT BAY AS DEPICTED BY LOCAL AND REGIONAL
MESOSCALE MODELS. HOWEVER...WINDS BACKING TO THE WEST/SOUTHWEST
OVERNIGHT AHEAD OF ADVANCING SFC RDG AXIS SHOULD KEEP LES BANDS OR
MESOLOW FEATURES MOVING ENOUGH EASTWARD TO EFFECTIVELY LIMIT
ACCUMULATIONS FOR THE OVERNIGHT HRS.
DECREASING CLOUD COVER OVERNIGHT AND LIGHT WINDS WILL ALLOW
TEMPERATURES TO FALL OFF OUTSIDE OF THOSE AREAS WHERE THE LAKE
EFFECT SNOWS LINGER. COLDEST TEMPERATURES ARE EXPECTED OVER THE FAR
EAST AND INTERIOR WEST SECTIONS. THE WRN INTERIOR ALONG THE WI BDR
WITH LIKELY SEE A FEW LOCATIONS PLUMMET TO 10 BELOW OR COLDER WHERE
TYPICAL COLD SPOTS OVER LUCE COUNTY COULD ALSO DIP NEAR 10 BELOW
ZERO. GENERALLY FOLLOWED A BLEND OF THE BETTER PERFORMING CANADIAN
REGIONAL GEM AND ECMWF FOR MIN TEMPS.
TUESDAY...DECENT MODEL AGREEMENT THAT LINGERING LAKE EFFECT OVER
NCNTRL CWA WILL BE PUSHED OUT OVR SOUTH CENTRAL LK SUPERIOR THROUGH
THE MORNING AS WINDS BECOME SSW AHEAD OF APPROACHING SHORTWAVE AND
SFC TROUGH OVER THE NRN PLAINS. MAY BE ABLE TO SNEAK IN SOME
SUNSHINE OVER MUCH OF THE CWA INTO EARLY AFTN BEFORE HIGH CLOUDS
START INCREASING AHEAD OF SHORTWAVE TROUGH DROPPING ACROSS THE
NORTHERN PLAINS. WARM ADVECTION SSW FLOW WILL ALLOW FOR MAX TEMPS TO
REBOUND INTO THE TEENS ACROSS MUCH OF THE AREA.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 310 PM EST MON DEC 23 2013
UPPER AIR PATTERN WILL CONSIST OF A 500 MB RIDGE ON THE WEST COAST
AND A TROUGH OVER THE NORTHERN PLAINS 00Z WED. NAM ALSO SHOWS A
CLOSED 500 MB LOW OVER NORTHERN ALBERTA 00Z WED. BOTH THE LOW AND
THE TROUGH MOVE TO THE EAST WITH THE REMAINS OF THE LOW HELPING TO
DIG A DEEP UPPER TROUGH INTO THE UPPER GREAT LAKES ON WED. NAM SHOWS
SOME 850-500 MB Q-VECTOR CONVERGENCE OVER THE CWA WITH DEEPER
MOISTURE TUE NIGHT LASTING INTO WED BEFORE BOTH MOVE OUT WED NIGHT
INTO THU. GFS AND ECMWF SHOW ABOUT THE SAME THING.
DID NOT MAKE TOO MANY CHANGES TO THE GOING FORECAST. CLIPPER TYPE
SYSTEM COMES IN FOR TUE NIGHT INTO WED AND WILL HAVE SOME LAKE
MICHIGAN LAKE ENHANCEMENT OVER THE ERN CWA WHICH WAS ALREADY COVERED
IN THE PREVIOUS FORECAST. COULD SEE UP TO 8 INCHES IN ERN
SCHOOLCRAFT AND LUCE COUNTIES FOR TUE NIGHT AND WED. DID LOWER
TEMPERATURES A BIT THOUGH EACH DAY FOR LOWS AND HIGHS TUE NIGHT
THROUGH THU AS THE TEMPERATURES SEEMED A BIT TOO WARM CONSIDERING
THE PERSISTENT COLD PATTERN WE HAVE BEEN IN.
IN THE EXTENDED...GFS AND ECMWF SHOW A 500 MB TROUGH OVER THE
CENTRAL U.S. 12Z FRI WITH A RIDGE OVER THE WESTERN U.S. UPPER FLOW
BECOMES MORE ZONAL OVER THE NORTHERN PLAINS AND UPPER GREAT LAKES
12Z SAT WHICH WILL MEAN A BRIEF WARMING TREND IS STARTING. A BROAD
500 MB TROUGH THEN MOVES INTO THE UPPER GREAT LAKES 12Z SUN AND INTO
MONDAY WITH COLD AIR ONCE AGAIN OVER THE AREA WITH THE DEEP UPPER
TROUGH. LAKE EFFECT SNOW WILL BE THE MAIN RULE FOR MOST OF THIS
FORECAST PERIOD WITH TEMPERATURES GOING BACK BELOW NORMAL SUNDAY
INTO MONDAY. CLIPPER SYSTEM MOVES THROUGH FOR SAT AND THIS WOULD BE
THE WARMEST DAY OF THE WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1240 PM EST MON DEC 23 2013
KIWD...NE WINDS WILL BACK MORE NNE LATER THIS AFTERNOON WHICH SHOULD
FINALLY ALLOW SOME HEAVIER LES BANDS TO MOVE INTO THE AREA. EXPECT
CONDITIONS TO LOWER FROM VFR TO IFR BY LATE AFTERNOON WITH THE
HEAVIER LES BANDS AND THEN IMPROVE TO VFR AFT 06Z TONIGHT AS WINDS
BACK MORE TO THE SW.
KCMX...MVFR CONDITIONS IN NE FLOW LES WILL CONTINUE THROUGH TONIGHT.
EXPECT IMPROVEMENT TO VFR BY LATE TUE MORNING AS WINDS BECOME SW.
KSAW...EXPECT IFR CONDITIONS IN NNE FLOW LES TO IMPROVE TO MVFR THIS
EVENING AS FLOW WEAKENS AND BACK MORE NNW THIS EVENING. CONDITIONS
WILL IMPROVE TO VFR LATE TONIGHT AS WINDS BECOME WEST AND THEN BACK
SW BY LATE TUE MORNING.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 343 PM EST MON DEC 23 2013
NORTHEAST WINDS WILL GRADUALLY DIMINISH THROUGH THE DAY. HEAVY
FREEZING SPRAY WILL REMAIN A PROBLEM OVER THE WEST AND NORTH CENTRAL
PORTIONS OF LAKE SUPERIOR UNTIL THE PRESSURE GRADIENT RELAXES A BIT
MORE IN THE AFTERNOON. AFTER A BRIEF RESPITE...SOUTH WINDS PICK UP
AGAIN AHEAD OF THE NEXT SYSTEM MOVING THROUGH TO THE NORTH OF LAKE
SUPERIOR TUESDAY NIGHT WITH GALE FORCE WINDS TO 35 KNOTS EXPECTED
THEN...MAINLY FOR THE EASTERN PORTION OF THE LAKE. WINDS DIMINISH
WEDNESDAY AND REMAIN BELOW 20 KNOTS THROUGH FRIDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY UNTIL 3 AM EST TUESDAY FOR MIZ004-005.
LAKE EFFECT SNOW ADVISORY UNTIL MIDNIGHT EST /11 PM CST/ TONIGHT
FOR MIZ002-009.
LAKE SUPERIOR...
GALE WATCH FROM LATE TUESDAY NIGHT THROUGH WEDNESDAY MORNING FOR
LSZ266.
HEAVY FREEZING SPRAY WARNING UNTIL 6 PM EST /5 PM CST/ THIS
EVENING FOR LSZ162-263-264.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...07
AVIATION...VOSS
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1244 PM EST MON DEC 23 2013
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 330 AM EST MON DEC 23 2013
SNOW SHOWERS ARE EXPECTED TO BE ON THE INCREASE TODAY...ESPECIALLY
FOR AREAS ACROSS THE SOUTHWEST CORNER OF LOWER MICHIGAN. THE SNOW
SHOWERS ARE EXPECTED TO BECOME LOCALLY HEAVY AND COULD BRING A FEW
INCHES OF SNOW TO SOME LOCAL AREAS. THE SNOW SHOWERS WILL CONTINUE
INTO THE EVENING HOURS BEFORE MOVING SOUTH AND WEST OF THE AREA
TOWARD DAYBREAK TUESDAY MORNING.
COLDER AIR WILL MOVE IN FOR TUESDAY ALONG WITH SOME POSSIBLE
SUNSHINE FOR A SHORT PERIOD OF TIME. THE AREA WILL SEE A COUPLE OF
WAVES OF LOW PRESSURE THEN MOVE IN FOR CHRISTMAS DAY AND ON
THURSDAY. THIS WILL BRING MORE SNOW ACCUMULATIONS TO THE
AREA...ESPECIALLY FOR AREAS NEAR THE LAKESHORE.
&&
.UPDATE...
ISSUED AT 1018 AM EST MON DEC 23 2013
WILL BE EXPANDING THE ADVISORY TO INCLUDE MUSKEGON AND KENT
COUNTIES. THE THREAT FOR HEAVY SNOW HAS DECREASED SOMEWHAT OVER VAN
BUREN AND KALAMAZOO...BUT WILL KEEP THEM IN THE ADVISORY.
RADAR INDICATES THE BEGINNINGS OF A DOMINANT SNOW BAND EXTENDING
SOUTHEAST THROUGH THE HOLLAND AREA. THIS IS CONSIDERABLY FARTHER
NORTH THAN PREVIOUS THINKING. RADAR RETURNS ARE STARTING TO SPREAD
TO THE NORTHWEST OVER LAKE MICHIGAN...SUGGESTING THAT THE DEPTH OF
THE BAND IS INCREASING WITH INVERSION HEIGHTS AHEAD OF THE UPPER
TROUGH APPROACHING FROM THE MIDWEST.
THIS BAND IS EXPECTED TO INTENSIFY AND WILL LIKELY UNDULATE. RADAR
ALREADY SUGGESTS A MESOLOW TRYING TO FORM WEST OF MUSKEGON. A
CONSENSUS OF SIMULATED REFLECTIVITY IN THE HIGH RESOLUTION MODELS
SUGGESTS THAT THE BAND WILL LIFT NORTH TOWARDS MUSKEGON AND KENT
COUNTY DURING THE COURSE OF THE DAY. A PARTICULARLY INTERESTING TIME
FRAME WILL BE EARLY TONIGHT WHEN THE HRRR AND DOWNSCALED NAM BRING A
PRONOUNCED MESOLOW ACROSS MUSKEGON AND KENT COUNTIES WITH A LIKELY
ENHANCED BURST OF SNOW.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 330 AM EST MON DEC 23 2013
THE MAIN CONCERN IN THE SHORT TERM IS THE POTENTIAL LOCALLY HEAVY
SNOW BAND THAT LOOKS LIKELY TO AFFECT THE SOUTHWEST CORNER OF THE
CWFA TODAY AND TONIGHT. WE WILL BE EXPANDING THE ADVISORY IN
COVERAGE TO INCLUDE OTTAWA AND BARRY COUNTIES. WE WILL ALSO BE
EXTENDING THE ADVISORY IN TIME TO GO THROUGH 12Z TUE. WE ARE
CONCERNED THAT MUSKEGON AND KENT COUNTIES MAY NEED TO BE INCLUDED IN
THE ADVISORY ALSO...HOWEVER WE ARE NOT QUITE CONFIDENT YET TO
INCLUDE THEM IN AT THIS TIME DUE TO UNCERTAINTY WITH THE MOVEMENT OF
THE NARROW BAND.
SNOW SHOWERS HAVE STARTED TO AFFECT THE SW CORNER OF THE CWFA
ALREADY THIS MORNING. THE SNOW SHOWERS ARE RESULTING FROM COLDER AIR
COMING ON THE NW FLOW IN PLACE. THIS NW FLOW IS ON THE SRN PERIPHERY
OF A LARGER SCALE SFC TROUGH THAT CURRENTLY IS ORIENTED FROM THE
STORM SYSTEM ACROSS THE NE U.S. ALL THE WAY TO MANITOBA. THE TROUGH
IS RESULTING FROM BOTH THE UPPER WAVE DIVING SE TOWARD THE AREA...
AND A CONTRIBUTION FROM THE GREAT LAKES.
WE EXPECT THE SNOW SHOWERS TO INTENSIFY DURING THE DAY TODAY. THE
SHORTWAVE DIVING IN FROM THE NW WILL HELP TO INCREASE INVERSION
HTS TO OVER 10K FEET AND CAUSE THE SFC TROUGH TO SHARPEN UP. THIS
WILL ENHANCE THE CONVERGENCE OVER PLENTY OF OVER LAKE INSTABILITY
WITH DELTA T/S SITTING AROUND THE MID TO UPPER TEENS. ANOTHER
FACTOR FOR HEAVIER SNOW AMOUNTS IS THE BEST CONVERGENCE OCCURS IN
THE FAVORED LAYER OF THE DGZ AROUND 2-4K FT ALOFT. WE EXPECT TO
SEE SNOW SHOWERS TO BECOME HEAVY ENOUGH TO SEE LOCAL SNOWFALL
RATES OF OVER AN INCH PER HOUR UNDER THE NARROW BAND.
WE EXPECT THE BAND TO GRADUALLY SHIFT NORTH THIS AFTERNOON RESULTING
FROM THE UPPER FLOW AHEAD OF THE WAVE. THE FLOW WILL SHIFT FROM THE
NW ORIENTATION TO A MORE WNW ORIENTATION. THIS WILL SHIFT THE
HEAVIEST SNOW BAND FROM THE CURRENT LOCATION TO AT LEAST A HOLLAND
TO HASTINGS CORRIDOR. SOME OF THE HIGHER RES MODELS ARE EVEN SHOWING
THE BAND GETTING INTO A GRAND HAVEN TO SRN KENT COUNTY LINE...AND
EVEN SOME ARE TAKING THIS TO A MUSKEGON TO GR LINE. THESE BANDS ARE
QUITE TRICKY TO NAIL DOWN...BUT WHERE THEY GO CAN CAUSE QUITE AN
IMPACT IN A SHORT TIME. OUR CONFIDENCE IS HIGH ENOUGH AT THIS TIME
TO ADD IN OTTAWA AND BARRY COUNTIES FOR NOW. THERE IS SOME TIME TO
WATCH THE EVOLUTION OF THE BAND AND EXPAND THE ADVISORY FURTHER
NORTH INTO KENT AND MUSKEGON COUNTIES IF NEEDED AS IT WOULD NOT
AFFECT THOSE AREAS UNTIL AT LEAST 21Z OR SO.
THE BAND WILL END UP AT ITS FARTHEST NORTH ORIENTATION BETWEEN
00-03Z BEFORE IT THEN SINKS BACK SOUTH AND THEN EXITS THE AREA
TOWARD 12Z TUE. THIS WILL OCCUR AS THE UPPER WAVE PASSES EAST OF THE
AREA TOWARD 12Z TUE. WE CAN NOT RULE OUT AMOUNTS REACHING WARNING
CRITERIA AT LOCATIONS THAT SEE THE BANDS LAST OVER A CERTAIN AREA
THE LONGEST LIKE ALLEGAN COUNTY AND NEAR HOLLAND. WE WILL STICK WITH
THE ADVISORY AND WATCH HOW SNOWFALL TRANSPIRES.
MOST OF THE SNOW SHOWERS SHOULD TRANSITION OFFSHORE BY TUE MORNING
AS THE FLOW BECOMES NNE BEHIND THE TROUGH PASSAGE. WE ACTUALLY
EXPECT AT LEAST SOME CLEARING WHICH WOULD ALLOW TEMPS TO FALL OFF
QUITE COLD AT INLAND LOCATIONS. WE COULD SEE SOME BELOW ZERO
READINGS UP TOWARD LEOTA IF SKIES CLEAR ENOUGH. SOME SUN WILL BE
FOUND ON TUE WITH THE SFC RIDGE MOVING OVERHEAD AND STRONG
SUBSIDENCE BUILDING IN BETWEEN THE TWO UPPER WAVES. SOME LIGHT SNOW
SHOWERS MAY MOVE INLAND ON TUE AS THE LOW LEVEL FLOW BECOMES WRLY
WITH THE RIDGE.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 330 AM EST MON DEC 23 2013
MORE ACCUMULATING LAKE EFFECT/ENHANCED SNOW IS EXPECTED STARTING
LATE CHRISTMAS EVE AND CONTINUING CHRISTMAS DAY AND THURSDAY. THIS
IS FUELED BY A SERIES OF SHORTWAVES ASSOCIATED WITH A 120 KT UPPER
LEVEL JET DIVING SE FROM WRN CANADA. TOTAL NEW SNOWFALL DURING THIS
48 HOUR PERIOD COULD EASILY EXCEED SIX INCHES WEST OF A CADILLAC TO
KALAMAZOO LINE.
THE FIRST BATCH OF SNOW FOR LATE CHRISTMAS EVE INTO CHRISTMAS
MORNING IS A COMBINATION OF WARM ADVECTION SNOW WITH SSW FLOW LAKE
ENHANCEMENT. SEVERAL INCHES OF ACCUMULATION ARE POSSIBLE ALONG THE
LK MI COAST NORTH OF HOLLAND DURING THIS TIME.
THEN A FAIRLY POTENT SHORTWAVE FOLLOWS IMMEDIATELY BEHIND THIS
STARTING LATE CHRISTMAS DAY AND LASTING INTO THURSDAY. MEAN FLOW
DURING THIS PERIOD IS WESTERLY BRINGING ADDITIONAL ACCUMULATIONS
ALONG AND WEST OF HIGHWAY 131. MORE LAKE EFFECT SNOW SHOWERS ARE
POSSIBLE THURSDAY NIGHT AND FRIDAY AS A FINAL NRN STREAM SHORTWAVE
COMES THROUGH BEFORE THE UPPER FLOW GOES BRIEFLY ZONAL.
SATURDAY CONTINUES TO LOOK LIKE A MILDER DAY AS H8 TEMPS ABOVE ZERO
ARRIVE FROM THE WEST AS A LOW MOVES EAST ACROSS LK SUPERIOR. THE
WARM UP SHOULD BE RATHER BRIEF HOWEVER AS MODELS SHOW MORE -20C H8
AIR SWEEPING IN ON SUNDAY OR SUNDAY NIGHT. THIS OUGHT TO GET THE
LAKE EFFECT CRANKED UP AGAIN.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1244 PM EST MON DEC 23 2013
THE MAIN FOCUS WILL CONTINUE ON A NARROW BAND OF HEAVY LAKE EFFECT
SNOW THIS AFTERNOON AND TONIGHT.
ENHANCEMENT BEGINNING IN THE WESTERN COUNTIES AS A WAVE OF ENERGY
MOVES INTO THE AREA. THE CONVERGENCE BAND IS SLOWLY DRIFTING NORTH
WITH ORIENTATION BECOMING MORE EAST-WEST. CONFIDENCE INCREASING FOR
THE BAND TO EFFECT MKG TO LANSING WITH SEVERAL HOURS OF MODERATE TO
HEAVY SNOW AND IFR/LIFR VISIBILITIES MAINLY WEST OF LANSING.
THE WEST-EAST ORIENTED BAND SHOULD MOVE SOUTHWARD AFTER 06Z TONIGHT
AND BEGIN IMPACTING AZO/BTL/JXN WHILE SNOW DIMINISHES AT MKG/GRR/LAN.
OUTSIDE OF THE POTENTIAL INTENSE BAND OF SNOW THROUGH TONIGHT...
MVFR SHOULD BE THE PREDOMINATE FLIGHT CATEGORY WITH CIGS 1500-2500
FEET AND SCATTERED/OCNL LIGHT SNOW REDUCING VSBYS TO 3-5 MILES.
&&
.MARINE...
ISSUED AT 419 AM EST MON DEC 23 2013
WE HAVE ISSUED A SMALL CRAFT ADVISORY FOR THE SOUTHERN TWO MARINE
ZONES. WEST TO NORTHWEST WINDS WILL COME UP ENOUGH TODAY TO
REQUIRE A HEADLINE.
THE NEXT HEADLINE WILL COME ON TUESDAY NIGHT AND INTO CHRISTMAS DAY.
A SOLID SMALL CRAFT ADVISORY AND POSSIBLE GALE WILL OCCUR AHEAD OF
THE CLIPPER SYSTEM EXPECTED TO MOVE IN AT THAT TIME.
&&
.HYDROLOGY...
ISSUED AT 857 AM EST MON DEC 23 2013
ARCTIC AIR RETURNS TODAY AND RIVERS ARE EXPECTED TO LOCK BACK IN
PLACE WITH ICE OVER THE NEXT FEW DAYS. THIS SHOULD SERVE TO
STABILIZE LEVELS. RELATIVELY FLAT ICE ON RIVERS IS A SIGN WATER IS
FLOWING RELATIVELY SMOOTHLY BENEATH. TEMPERATURES WILL REMAIN
BELOW FREEZING...AND WILL RESULT IN CONTINUED ICE GROWTH ON RIVERS
IN SOUTHWEST LOWER MICHIGAN. UNDER THESE CONDITIONS THE THREAT FOR
ICE JAMS IS LOW.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL 7 AM EST TUESDAY FOR MIZ056-064-
071-072.
WINTER WEATHER ADVISORY UNTIL 7 AM EST TUESDAY FOR MIZ050-057-
065.
LM...SMALL CRAFT ADVISORY UNTIL 1 PM EST TUESDAY FOR LMZ844-845.
&&
$$
UPDATE...TJT
SYNOPSIS...NJJ
SHORT TERM...NJJ
LONG TERM...MEADE
AVIATION...63
HYDROLOGY...WALTON
MARINE...NJJ
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1246 PM CST MON DEC 23 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 356 AM CST MON DEC 23 2013
LIGHT SNOW CONTINUES EARLY THIS MORNING FROM CENTRAL MN THROUGH THE
TWIN CITIES AND WEST CENTRAL WI UNDER AN UPPER LEVEL TROUGH.
ANIMATION OF THE KMPX RADAR INDICATES A LOW/MID LEVEL CIRCULATION
ACROSS CENTRAL MN... WHICH VERIFIES WELL WITH THE RAP AVERAGE
850-700MB HEIGHT FIELD. THE UPPER TROUGH AND LOW LEVEL CYCLONIC
CIRCULATION WILL DRIFT EVER SO SLOWLY TO THE SOUTHEAST THROUGH THIS
EVENING. THIS WILL MAINTAIN PLENTY OF CLOUDS AND LIGHT SNOW ACROSS
EASTERN MN AND WESTERN WI THROUGH THE DAY WITH THE LIGHT SNOW
DIMINISHING ACROSS WEST CENTRAL WI THIS EVENING. SNOW AMOUNTS TODAY
ARE IN THE TRACE TO 1 INCH CATEGORY FOR THE MN CWA WITH 1 TO 2
INCHES FOR WEST CENTRAL WI. SNOW AMOUNTS IN WEST CENTRAL WI TONIGHT
ARE LESS THAN A HALF INCH.
THE TEMPERATURE FORECAST FOR TODAY AND TONIGHT IS RATHER
PROBLEMATIC. ONE CONCERN TODAY IS HOW MUCH OF A REBOUND WE WILL HAVE
ACROSS THE WESTERN HALF OF MINNESOTA AS THE ARCTIC AIR CONTINUES TO
POUR IN WHILE EASTERN AREAS HAVE SOME INSULATION FROM THE CLOUDS.
JUST ABOUT EVERYBODY IN THE MN RIVER VALLEY EARLY THIS MORNING IS
CURRENTLY NEAR 10 BELOW. LOWS COULD EASILY REACH 15 BELOW TO 20
BELOW ZERO BY DAYBREAK. THE CURRENT THINKING IS THAT WE WILL ONLY
MAKE IF BACK TO THE 5 BELOW TO 10 BELOW RANGE IN THE WEST TODAY WITH
SINGLE DIGITS IN EASTERN MN WITH SOME TEENS IN OUR FAR EASTERN
COUNTIES IN WI. WITH THE ARCTIC HIGH REACHING OUR WESTERN MN
COUNTIES THIS EVENING...TEMPERATURES SHOULD CRATER FOR A 6 TO 8
HOUR PERIOD BEFORE RISING AFTER MIDNIGHT AS SOUTHERLY LOW LEVEL
FLOW DEVELOPS AHEAD OF AN APPROACHING CLIPPER. HENCE... LOWS
TONIGHT ARE A BIG CONCERN. THE GEM AND ECMWF ARE ON THE COLD SIDE
OF GUIDANCE WITH 20 BELOW TO 30 BELOW ZERO FOR MOST OF OUR MN CWA
WITH 10 BELOW TO 20 BELOW ZERO IN WI. THE AREA WHERE THE COLDEST
TEMPERATURES WILL LIKELY BE REACHED IS ACROSS CENTRAL MN WHERE
SEVERAL INCHES OF NEW SNOW HAS FALLEN AND THE SNOW DEPTH IS NEARLY
A FOOT. THEREFORE...WENT NEAR 25 BELOW ACROSS CENTRAL MN WITH 15
BELOW TO 20 BELOW ACROSS SOUTHERN MN WITH AROUND 10 BELOW IN THE
TWIN CITIES AS WEST CENTRAL WI. A NON-DIURNAL TEMPERATURE TREND
WAS INSERTED ACROSS WEST CENTRAL MN DURING THE OVERNIGHT HOURS.
THE COLD TEMPERATURES AND NORTHWEST WINDS OF 10 TO 20 MPH THROUGH
THIS EVENING CERTAINLY SUPPORT THE CURRENT WIND CHILL WARNING AND
WIND CHILL ADVISORY HEADLINES WITH NO CHANGES BEING MADE AT THIS
TIME.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 356 AM CST MON DEC 23 2013
NOT MUCH HAS CHANGED IN THE LONG TERM WITH THIS UPDATE. WE WILL
MAINTAIN NORTHWEST FLOW AS WE REMAIN WEDGED BETWEEN A MEAN ERN PAC
RIDGE AND ERN NOAM TROUGH.
TUESDAY STILL LOOKS TO FEATURE STRONG SOUTHERLY WINDS AND A QUICK
BURST OF SNOW AS THE STRONG WAVE CURRENTLY ROUNDING THE TOP OF THE
RIDGE OVER THE GULF OF ALASKA COMES SLIDING ACROSS THE AREA. MODEL
AGREEMENT REMAINS HIGH WITH THIS SNOW...WITH ONLY MINOR TIMING
DIFFERENCES EXISTING AT THIS POINT. ALL MODELS SHOW FAIRLY
WIDESPREAD 0.1 TO 0.2 INCH QPF AMOUNTS FALLING WITH THIS SYSTEM.
ONLY EXPECT SNOW RATIOS TO RANGE FROM 15-18:1 DURING THE HEAVIEST
SNOW AS COMBINATION OF STRONG WAA IN THE H85-H7 LAYER WILL LIMIT THE
DEPTH OF THE DENDRITIC GROWTH ZONE AND STRONG WINDS FROM THE SFC
THROUGH THE DEPTH OF THE CLOUD LAYER WILL HELP BREAK APART ANY
CRYSTALS THAT TRY TO GET TOO BIG. THESE RATIOS WITH THE EXPECTED QPF
WILL RESULT IN A GOOD 1.5 TO 3.5 INCHES OF SNOW AREA WIDE. NAM/GFS
CONTINUE TO SHOW MIXING RATIOS ON THE 295K SFC UP AROUND 2.5
G/KG...WHICH SUPPORTS THE CURRENTLY EXPECTED SNOWFALL AMOUNTS.
ALTHOUGH THESE AMOUNTS FALL BELOW THE 4 INCH BENCHMARK FOR A WINTER
WEATHER ADVY...THE FACT THAT THIS WILL BE A FAIRLY HEALTHY BURST OF
SNOW FOR ABOUT 4 HOURS DURING THE AFTERNOON/EVENING OF CHRISTMAS EVE
WHEN TRAVEL WILL BE HEAVIER ACROSS THE AREA...FUTURE SHIFTS WILL
HAVE TO WEIGH THE MERITS OF ISSUING AN ADVY BASED ON THE POTENTIAL
TRAVEL IMPACTS.
FOR CHRISTMAS DAY...ANOTHER STRONG UPPER WAVE WILL BE PASSING DOWN
THROUGH THE AREA. THE NAM IS SHOWING HEIGHT FALLS WITH THIS WAVE ON
THE ORDER OF 160M IN 12 HOURS...WITH A 5 UNIT PV ANOMALY COMING DOWN
AS WELL. ALL OF THIS POINTS TO ANOTHER BURST OF SNOW AS THIS COMES
DOWN...THOUGH IT WILL BE COMING DOWN IN THE DRY WAKE OF TUESDAYS
SYSTEM...AS THOSE SPEC HUMIDITIES THAT WILL BE UP AROUND 2.5 G/KG
TUESDAY WILL BE DOWN BETWEEN 0.5 AND 1 G/KG WEDNESDAY...HENCE WHY
QPF INDICATED BY THE MODELS IS SPOTTY AT BEST. THIS JUST LOOKS TO BE
ANOTHER SHOT AT SEEING A FAIRLY WIDESPREAD HALF INCH OF SNOW ON
LIQUID AMOUNTS THAT ARE A TRACE OR A HUNDREDTH OF AN INCH. AFTER
THIS WE MAY SEE REPEAT PERFORMANCES WITH SOME LIGHT SNOW/FLURRIES
AGAIN ON THURSDAY AND FRIDAY AS WE CONTINUE TO GET PEPPERED BY WEAK
UPPER WAVES IN THE NW FLOW. FOR SATURDAY...THE WRN RIDGE LOOKS TO
SHIFT FAR ENOUGH EAST TO PUSH THESE WAVES NORTH OF THE AREA...BUT
THE RETURN OF THE ARCTIC AIR SUNDAY WILL BRING ABOUT THE NEXT SHOT
AT A DUSTING.
TEMPERATURES WILL BE ON A BIT OF A ROLLER COASTER OVER THE NEXT
WEEK...THOUGH WE WILL BE BOUNCING BETWEEN NEAR NORMAL AND ABOUT 20
DEGREES BELOW NORMAL. WE WILL MAINTAIN OUR RESIDENCE IN THE ARCTIC
AIR THROUGH TONIGHT...BRIEFLY SHIFT OUT OF IT TUESDAY THROUGH
WEDNESDAY...RECEIVE A MORE GLANCING BLOW OF ARCTIC AIR WEDNESDAY
NIGHT THROUGH THURSDAY NIGHT...GET OUR WARMEST BREAK FROM THE ARCTIC
AIR FRIDAY AND SATURDAY...THEN SEE WHAT COULD BE OUR COLDEST BLAST
OF AIR YET FOR SATURDAY NIGHT INTO SUNDAY OF NEXT WEEKEND. FROM THE
WIND CHILL HEADLINE END OF THINGS...THE GLANCING BLOW OF ARCTIC AIR
WEDNESDAY NIGHT THROUGH THURSDAY NIGHT LOOKS TO BE JUST WARM ENOUGH
TO CEASE THE NEED FOR ANY WIND CHILL HEADLINES AFTER TUESDAY MORNING
UNTIL THE NEXT HEALTHY DOSE OF ARCTIC AIR RETURNS SUNDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1232 PM CST MON DEC 23 2013
MVFR VIS/CIGS WITH LIGHT SNOW WILL LINGER FOR THE REMAINDER OF THE
AFTERNOON IN WI...BUT SLOWLY CLEAR FROM WEST TO EAST WITH TIME.
VFR TONIGHT WITH CLEAR SKIES AND FRIGID TEMPS. ACCUMULATING SNOW
IS EXPECTED TOMORROW. EXPECT CONDITIONS TO DETERIORATE QUICKLY
ONCE THE SNOW BEGINS TOMORROW AFTERNOON.
KMSP...
NO AVIATIN WEATHER CONCERNS IN THE COLD SHORT TERM WITH NEARLY
CLOUD FREE SKIES. WE HAVE HIGH CONFIDENCE THAT THE SNOW WILL BEGIN
SOMETIME BETWEEN 12-1PM TOMORROW AND CIGS/VIS WILL QUICKLY BE
REDUCED. THE EVENING RUSH TONIGHT AND TUESDAY MORNING COMMUTE
WILL BE FINE WITH VFR CONDITIONS. THIS WILL DEFITELY IMPACT THE
EVENING RUSH...HOWEVER...WITH IFR/LIFR CONDITIONS DURING THE MID
TO LATE AFTERNOON. WE WILL CONTINUE TO REFINE THE TIMING OF THE
ONSET OF SNOW TOMORROW...BUT WE FEEL WE HAVE A GOOD HANDLE
/WITHIN A COUPLE HOURS/ AS OF RIGHT NOW.
/OUTLOOK FOR KMSP/
TUE NIGHT...IFR WITH SN IN THE EVENING WINDS S AT 10G20KTS.
WED...MVFR WITH -SN/BLSN POSSIBLE. WINDS W AT 15G25KTS.
THU...VFR. WINDS W AT 10KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WIND CHILL ADVISORY UNTIL NOON CST TUESDAY FOR MNZ042-043-
049>051-058-059-066>069-076-077-084-085-091>093.
WIND CHILL WARNING UNTIL NOON CST TUESDAY FOR MNZ041-047-048-
054>057-064-065-073>075-082-083.
WI...NONE.
&&
$$
SHORT TERM...RAH
LONG TERM...MPG
AVIATION...CLF
AREA FORECAST DISCUSSION
NWS GRAY ME
1200 PM EST MON DEC 23 2013
.SYNOPSIS...
A WAVE OF LOW PRESSURE WILL RIDE NORTHEAST ALONG A COLD FRONT
THIS AFTERNOON, PRODUCING FREEZING RAIN AND A WINTRY MIX OF
PRECIPITATION ACROSS MUCH OF THE AREA. THE COLD FRONT WILL
FINALLY MOVE OUT TO SEA BY EVENING. HIGH PRESSURE AND COLDER AIR
WILL THEN BUILD OVER THE REGION FOR THE MIDWEEK PERIOD. LOW
PRESSURE WILL PASS NORTH OF THE AREA AND DRAG A TRAILING COLD
FRONT ACROSS THE REGION EARLY FRIDAY FOLLOWED BY HIGH PRESSURE FOR
LATE FRIDAY AND SATURDAY.
&&
.NEAR TERM /UNTIL 5 PM THIS AFTERNOON/...
1155 AM...ACROSS THE LOWER CONNECTICUT VALLEY ZONES TEMPERATURES
HAVE GRADUALLY WARMED ABOVE FREEZING AND THE STEADIER PRECIPITATION
HAS ENDED. THEREFORE...WE`VE ALLOWED THE FREEZING RAIN ADVISORY TO
EXPIRE THERE. OTHERWISE...ONLY MINOR ADJUSTMENTS FOR THIS ESTF
UPDATE.
PREV DISC...
935 AM...THIS FINAL ROUND OF FREEZING RAIN WILL PRODUCE UP TO AN
ADDITIONAL 1/3 TO AS MUCH AS 1/2 INCH OF ICE BEFORE IT ENDS FROM
SOUTHWEST TO NORTHEAST ACROSS THE AREA DURING THE AFTERNOON HOURS.
THE ICE STORM WARNING HAS BEEN EXTENDED THROUGH 4 PM SINCE THIS
AREA HAD THE GREATEST ICE ACCRETION PRIOR TO TODAY`S EVENT AND IS
MOST VULNERABLE TO THE ADDITIONAL GLAZE. ELSEWHERE...I EXPECT TOTAL
ICE ACCRETION TO BE UNDER 1/2 INCH AND IN THE ADVISORY CATEGORY.
PREV DISC...
659 AM...I MADE SOME MINOR ADJUSTMENTS TO 1ST PERIOD GRIDS TO
REFLECT CURRENT MESONET AS WELL AS RADAR TRENDS. ON THE WATERS...I
EXTENDED THE CURRENT SMALL CRAFT ADVISORY THROUGH LATE TONIGHT.
PREV DISC...
UPDATE...MADE A FEW MINOR CHANGES TO THE GRIDS TO ACCOUNT FOR
CURRENT OBSERVATIONAL TRENDS. HAVE ALSO DELAYED THE TIMING OF
CATEGORICAL POP UNTIL AFTER 12Z BASED ON UPSTREAM OBS.
PREVIOUS DISCUSSION...COLD AIR DAMMING REMAINS FIRMLY ENTRENCHED
E OF THE MTNS THIS MORNING. ONLY RELATIVE WARMTH TO BE FOUND
ACROSS THE CWFA IS IN THE CT RIVER VALLEY...WHERE READINGS ARE IN
THE MID 30S. THIS IS THE CRITICAL PART OF THE FORECAST...AS WEAK
LOW PRES AND SLUG OF PCPN LIFTS NEWD ALONG THE EAST COAST.
THRU THIS MORNING THERE IS NO REAL MECHANISM TO SCOUR OUT THE LLVL
COLD AIR. SO THE EXPECTATION IS THAT AREAS BELOW FREEZING WILL
REMAIN THAT WAY...PROBABLY INTO THE AFTERNOON. RECENT RAP AND
HRRR RUNS KEEP MUCH OF THE AREA BELOW FREEZING THRU 18Z. H8 TEMPS
ARE COOLING SLIGHTLY...BUT 06Z GYX SOUNDING CONFIRMS THAT WE STILL
HAVE A WARM NOSE OF +10 C AT 900 MB. AS THE COLUMN RE-SATURATES
AND PCPN BEGINS FALLING...FZRA IS REALLY THE ONLY SCENARIO FOR
MUCH OF THE AREA. THE CT RIVER VALLEY AND POSSIBLY THE IMMEDIATE
COASTLINE WILL SEE JUST RNFL WITH TEMPS ABOVE FREEZING. IN THE
FAR N AROUND JACKMAN...COLD AIR IS STILL DEEP ENOUGH FOR A MIX OF
PL OR SN AT TIMES. NAM12 ACTUALLY HAS A REALLY GOOD HANDLE ON
THERMAL PROFILE ATTM...SO BASED WX GRIDS OFF MODEL THICKNESS
VALUES.
FOR QPF A BLEND OF THE 23/00Z ECMWF AND NERFC WAS PREFERRED. THIS
HAD GENERALLY 0.25 INCHES QPF RUNNING FROM KCON THRU KLEW AND TO KAUG.
THE COAST WAS CLOSE TO 0.50 INCHES. USING THESE VALUES AND
ACCOUNTING FOR SOME LOSS TO RUNOFF AND GRADUAL SURFACE WARMING...ICE
ACCRETION VALUES OF AN ADDITIONAL 0.1 TO 0.25 INCHES IS POSSIBLE.
THE GREATEST THREAT FOR ADDITIONAL SIGNIFICANT ICE ACCUMULATION IS
JUST INLAND FROM THE COAST TO ABOUT A KLEW TO KAUG LINE.
ADDITIONALLY FZRA WILL BE LIKELY DURING THE MORNING
COMMUTE...WHICH WILL ADD TO THE HAZARD.
GIVEN THESE EXPECTATIONS HAVE ADJUSTED HEADLINES TO MATCH. HAVE
DROPPED WARNINGS ACROSS NH...AND CONVERTED COOS COUNTY TO A WINTER
WX ADVISORY. NRN CARROLL COUNTY WILL BE INCLUDED WITH FZRA
ADVISORY TO THE S. WILL ALLOW THE WRN NH ZONES TO EXPIRE MID
MORNING. WINTER STORM WARNINGS IN NRN ME MTNS WILL ALSO BE
DROPPED IN FAVOR OF WINTER WX ADVISORIES FOR COMBINATION OF SN AND
FZRA. ICE STORM WARNINGS WILL REMAIN AS IS. EVEN THOUGH SOME AREAS
MAY NOT SEE 0.5 INCHES OF ICE ACCRETION...CONFUSION OF DOWNGRADING
THE HEADLINE AS FZRA IMPACTS MORNING COMMUTE ARGUED FOR THE
CONTINUITY.
&&
.SHORT TERM /5 PM THIS AFTERNOON THROUGH 6 PM TUESDAY/...
S/WV TROF DROPPING THRU THE OHIO VALLEY WILL FINALLY BE THE
IMPETUS THAT PUSHES FRONTAL BOUNDARY THRU THE REGION. AS FLOW
BECOMES NW AND CAA COMMENCES WE WILL FINALLY MIX OUT THE LLVLS OF
THE ATMOSPHERE. GIVEN SUCH WARMTH ALOFT...THIS MAY ACTUALLY CAUSE
TEMPS TO JUMP UP SEVERAL DEGREES IN A SHORT AMOUNT OF TIME. THIS
IS THE MOST LIKELY TIME THAT HIGH TEMPS WILL BE REACHED.
CROSS BARRIER FLOW AND UPPER TROF SWINGING OVERHEAD WILL ALSO
SUPPORT SCT SHSN IN THE MTNS. SEASONABLY COLD AIR LURKING JUST
OVER THE INTERNATIONAL BORDER WILL ONCE AGAIN RETURN FOR THE AREA
TUE...WITH HIGHS REMAINING IN THE 20S.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
MODELS ARE FAIRLY SIMILAR FOR THE THE WEEK. HIGH PRESSURE WILL
BUILD OVER THE AREA TUESDAY AND WEDNESDAY AND MOVE EAST OF THE
AREA THURSDAY. LOW PRESSURE WILL TRAVEL NORTH OF NEW ENGLAND
THROUGH SOUTHERN CANADA THURSDAY AND FRIDAY. A COLD FRONT WILL
MOVE THROUGH MAINE AND NEW HAMPSHIRE LATE THURSDAY NIGHT. A WARM
FRONT WILL MOVE NORTH OF THE AREA FRIDAY OR SATURDAY FOLLOWED BY A
COLD FRONT SUNDAY OR MONDAY. THE MODELS DIFFER ON THE TIMING OF
THE SYSTEM FOR NEXT WEEKEND WITH THE ECMWF BEING SLOWER AND
TRACKING THE SURFACE LOW THROUGH MAINE VERSUS THE GFS TRACKING THE
LOW NORTH OF THE ST LAWRENCE RIVER.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
SHORT TERM...LIFR AND IFR CONDITIONS WILL CONTINUE INTO THE EARLY
AFTERNOON. FZRA AND FZDZ WILL CONTINUE AS WELL. BY THE LATE
AFTERNOON NW WINDS WILL BEGIN SLOWLY CLEARING AND DRYING THE AREA
OUT FROM W TO E.
LONG TERM...EXPECT VFR THROUGH THE PERIOD.
&&
.MARINE...
SHORT TERM...MARGINAL SCA CONDITIONS WILL CONTINUE INTO THE EARLY
AFTERNOON. WINDS WILL REMAIN MOSTLY BELOW 25 KTS...BUT SEAS WILL
REMAIN NEAR 5 FT. CAA OVER THE WATERS TUE COULD BRINGS WINDS AND
SEAS BACK TO SCA THRESHOLDS.
LONG TERM...SMALL CRAFT CONDITIONS ARE POSSIBLE WEDNESDAY THROUGH FRIDAY.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...WINTER WEATHER ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
MEZ007>009.
ICE STORM WARNING UNTIL 4 PM EST THIS AFTERNOON FOR MEZ012>014-
019>022-024>028.
FREEZING RAIN ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
MEZ018-023.
NH...WINTER WEATHER ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
NHZ001-002.
FREEZING RAIN ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
NHZ004-006-008>010-013-014.
FREEZING RAIN ADVISORY UNTIL NOON EST TODAY FOR NHZ003-005-007.
MARINE...SMALL CRAFT ADVISORY UNTIL 5 AM EST TUESDAY FOR ANZ150-152-154.
&&
$$
ES
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
243 PM EST MON DEC 23 2013
.SYNOPSIS...
A SLOW MOVING COLD FRONT APPROACHING FROM THE WEST WILL MOVE OFF THE
COAST TONIGHT. DRIER AND COOLER AIR WILL SPREAD ACROSS THE REGION IN
THE WAKE OF THE COLD FRONT. A MOSTLY DRY COLD FRONT WILL PASS ACROSS
THE AREA FRIDAY...MAINTAINING SEASONABLE TEMPERATURES INTO THE
WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 240 PM MONDAY...THE COLD FRONT CONTINUES TO PRESS EASTWARD AS
IT IS APPROACHES RALEIGH BUT IS IT STILL LAGS A BIT TO THE SOUTH. A
POSSIBLE PREFRONTAL TROUGH IS RUNNING AHEAD OF THE FRONT TO THE
SOUTH. THE 18Z UTC RUC IS SHOWING THE 850 LOW LEVEL JET MAX CENTERED
OVER SOUTH CAROLINA AND THIS FEATURE WILL SHIFT NORTH OUT OF THE
AREA BY 22 UTC. THIS APPEARS TO BE THE WHAT IS ENHANCING THE LOW TOP
CONVECTION IN INLAND AREAS OF SOUTHEAST NORTH CAROLINA.
SEA FOG IS NOW BREAKING UP ALONG THE GEORGETOWN COAST AND WILL
LINGER FOR THE NEXT HALF HOUR BEFORE BECOMING A NONE FACTOR.
MODELS STILL CONTINUE TO BRING A FRONT TO THE COAST BY 7 PM BUT THE
MODELS MAINTAIN A GOOD CHANCE OF SHOWERS EARLY THEN SLOWLY TAPER THE
RAIN OFF OVERNIGHT. QPF VALUES APPEAR TO BE LESS THAN A HALF OF AN
INCH.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 240 PM MONDAY...A DRIER COLUMN WILL BUILD ACROSS THE AREA
EARLY ON IN THE SHORT TERM PERIOD AS THE SUBTROPICAL MOISTURE PLUME
SHIFTS AWAY FROM THE COAST. LINGERING LOW CLOUDS IN THE
MORNING...BUT RAINFALL WILL COME TO AN END WITH THE DEPARTURE OF THE
AFOREMENTIONED PLUME AND AS STRONG SUBSIDENCE DEVELOPS IN THE H85-H5
LAYER. THUS THE TREND FOR TUESDAY IS CLEARING SKIES AND MUCH COOLER
TEMPERATURES COMPARED TO THE RECENT WARM SPELL. COLDER AIR ARRIVES
TUESDAY NIGHT INTO WEDNESDAY MORNING (LOWS IN THE MID TO UPPER 20S)
WITH COLD AIR ADVECTION LEADING TO HIGHS ONLY IN THE 40S FOR
CHRISTMAS DAY. INCREASING CLOUDS WEDNESDAY NIGHT WILL RESULT IN
SLIGHTLY WARMER MINS...BUT THEY WILL STILL BE AT OR JUST BELOW
FREEZING ACROSS THE FORECAST AREA.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 240 PM MONDAY...THE EXTENDED FORECAST CONTINUES TO LOOK RATHER
UNEVENTFUL WITH THE OVERALL MID LEVEL PATTERN DEPICTING A MODEST
TROUGH OVER THE EASTERN THIRD OF THE U.S. AND MODEST RIDGING ACROSS
THE SOUTHWEST. AT THE SURFACE THERE WILL BE TWO FRONTS THAT MOVE
ACROSS THE AREA THAT WILL ONLY SERVE TO RESET ANY TEMPERATURE
MODIFICATION.
TEMPERATURES THURSDAY AND FRIDAY WILL BE SLIGHTLY BELOW CLIMATOLOGY
AS THE COLD AIR MASS THAT FOLLOWS THE SYSTEM MOVING THROUGH TODAY
AND TONIGHT LINGERS. THERE IS A SLIGHT MODIFICATION OF TEMPERATURES
SATURDAY AND SUNDAY VIA AIRMASS MODIFICATION. THIS BRIEF WARMUP IS
SHORT LIVED AS ANOTHER DRY FRONT MOVES ACROSS MONDAY. THE TRENDS ARE
RATHER CONSISTENT AND THE CONSOLATION IS THAT THE WILD TEMPERATURE
SWINGS WE HAVE EXPERIENCED THE PAST FEW WEEKS ARE AT LEAST
TEMPORARILY A THING OF THE PAST.
FINALLY THE ONLY POPS IN THE FORECAST ARE THURSDAY INTO EARLY FRIDAY
FROM WHAT APPEARS TO BE MORE OF A WEAK WAVE MOVING IN FROM THE
SOUTHWEST FLOW ALOFT THAT SKIRTS THE AREA. THE SURFACE COASTAL
TROUGH PATTERN SEEMS TO HAVE DISAPPEARED. REGARDLESS OF THE FORCING
MECHANISMS...POPS REMAIN LOW AND MOSTLY CONFINED TO THE COASTAL
AREAS.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
AS OF 18Z...STUBBORN SEA FOG MAY HANG ON AT CRE FOR THE FIRST HOUR
OR SO...OTHERWISE LOOK FOR MAINLY MVFR CONDITIONS THIS AFTERNOON.
FRONTAL BOUNDARY WILL PASS THROUGH THE WESTERN TERMINALS BY LATE
AFTERNOON...REACHING THE COAST AROUND 00-02Z. WINDS WILL SHIFT TO
THE NORTH BEHIND THE FRONT...WITH LIGHT RAIN OR DRIZZLE
EXPECTED...ALONG WITH LOWERING CEILINGS. MOST OF THE OVERNIGHT HOURS
WILL BE IFR...LINGERING INTO THE DAYLIGHT HOURS ALONG THE COAST
TUESDAY. LOOK FOR CONDITIONS TO IMPROVE TO NEAR VFR TOWARD THE END
OF THE FORECAST PERIOD...IMPROVING FROM WEST TO EAST.
EXTENDED OUTLOOK...VFR THROUGH THE PERIOD.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 240 PM MONDAY...THE DENSE FOG ADVISORY WILL BE ALLOWED TO
EXPIRE AT 3 PM AS IT CONTINUE TO SLOWLY DISSIPATE AND ADVECT TO THE
NORTH NORTHEAST AHEAD OF A SLOW MOVING FRONT FOR THE WATERS MAINLY
SOUTH OF LITTLE RIVER INLET.
THE FRONTAL PASSAGE ACROSS THE WATERS IS EXPECTED AFTER 7 PM AND
WITH THIS FRONT A GOOD PUSH OF OFFSHORE FLOW IS EXPECTED AND THE
SEAS WILL FALL BELOW SMALL CRAFT CONDITIONS AT 8 PM SOUTH OF LITTLE
RIVER INLET AND 2 AM FOR THE WATERS TO THE NORTH. SEAS SHOULD RELAX
LATE AND WILL BEGIN AT 4 TO 6 FEET BUT WILL SETTLE OUT TO A RANGE
OF 2 FEET NEAR SHORE AND 5 FEET AT 20 MILES OFF THE COAST.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 240 PM MONDAY...N TO NW FLOW WILL PREVAIL IN THE WAKE OF THE
COLD FRONT TUESDAY AND TUESDAY NIGHT...THEN THE WIND WILL VEER TO
THE NE DURING WEDNESDAY. WINDS WILL DIMINISH TO AROUND 10 KT OR LESS
BY WEDNESDAY NIGHT AS WEAKENING RIDGE OF HIGH PRESSURE BUILD INTO
THE VICINITY. THE OFFSHORE TRAJECTORY WILL RESULT IN A RANGE OF SEAS
THAT WILL BE FETCH LIMITED NEAR THE COAST. FOR THE MOST PART SEAS
WILL APPROACH 5 FT CLOSER TO 20 NM OFFSHORE THROUGH MOST OF THE
PERIOD WITH 1-2 FT SEAS NEAR THE COAST.
LONG TERM /THURSDAY THROUGH SATURDAY/...
AS OF 240 PM MONDAY...ONCE AGAIN THE CENTRAL THEME FOR THE EXTENDED
COASTAL WATERS FORECAST IS A NORTHERLY COMPONENT TO THE WINDS. FOR
THURSDAY THE FLOW WILL BE 10-15 KNOTS WITH A COUPLE OF ROGUE GUSTS
OVER 15 POSSIBLE. AS A DRY FRONT MOVES ACROSS FRIDAY SPEEDS WILL
INCREASE TO 15-20 KNOTS. SATURDAY WINDS DROP BACK DOWN TO 10-15
KNOTS...AGAIN FROM THE NORTH. SEAS WILL FOLLOW THE WIND SPEED TRENDS
WITH 2-4 FEET THURSDAY AND SATURDAY WITH 3-5 FEET FOR FRIDAY.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...DENSE FOG ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR AMZ254-
256.
SMALL CRAFT ADVISORY UNTIL 8 PM EST THIS EVENING FOR AMZ254-
256.
SMALL CRAFT ADVISORY UNTIL 2 AM EST TUESDAY FOR AMZ250-252.
&&
$$
NEAR TERM...DRH
SHORT TERM...SRP
LONG TERM...SHK
AVIATION...DL/DRH
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
556 PM EST MON DEC 23 2013
.SYNOPSIS...
A SLOW-MOVING FRONTAL BOUNDARY ALONG THE EAST COAST WILL PUSH OUT
TO SEA TONIGHT. NOTICEABLY COLDER AIR WILL RETURN TO THE AREA BY
CHRISTMAS EVE AND CONTINUE INTO THE END OF THE WEEK. ASIDE FROM
THE POSSIBILITY OF A COUPLE OF WEAK CLIPPER TYPE SYSTEMS DROPPING
OUT OF THE GREAT LAKES...NO SIGNIFICANT STORMS ARE EXPECTED FOR
THE UPCOMING WEEK.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
WEAK WAVE OF LOW PRES NR VIRGINIA BEACH SLOWING EXIT OF SFC FRONT
ALONG THE E COAST THIS EVENING. RAIN CONTINUES TO FALL EARLY THIS
EVENING WELL WEST OF THE FRONT IN REGION OF FGEN FORCING BENEATH
RIGHT ENTRANCE TO POWERFUL UPPER JET. LATEST RAP OUTPUT CAPTURES
THIS FORCING THE THE 8-7H LVL AND IMPLIES THE LAST OF THE RAIN
WILL EXIT LANCASTER CO BY 00Z.
THE UPPER TROF AXIS IS STILL WELL TO THE WEST AND WILL BE
APPROACHING TONIGHT AND TUESDAY. THE DEEP MOISTURE WILL HAVE
PUSHED OFF WELL TO THE EAST BY OVERNIGHT...BUT BETWEEN GR LAKES
MOISTURE AND THE INCREASE IN UPPER FORCING...IT WILL BE ENOUGH TO
TRIGGER SOME SNOW SHOWERS OVER THE AREAS DOWNWIND OF LAKE ERIE
INTO NW PA. AT THIS POINT AMOUNTS LOOK TO AVERAGE LESS THAN
ADVISORY LEVELS IN MOST AREAS...BUT WOULD NOT BE SURPRISED TO SEE
A FEW REPORTS OF 3 INCHES ACROSS THE SNOWBELT OF NW WARREN CO THROUGH
LATE TUESDAY.
LOWS TONIGHT WILL END THE RECENT SPELL OF VERY MILD WEATHER WITH
TEENS AND 20S GETTING BACK VERY CLOSE TO NORMAL.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
THE UPPER TROF WILL PASS BY EARLY TUESDAY AFTERNOON WITH THE
ACCOMPANYING POCKET OF COLD AIR ALOFT HELPING SUPPORT FAIRLY
WIDESPREAD SNOW SHOWERS AND FLURRIES. THE BEST CHANCE OF SEEING A
COATING TO A COUPLE OF INCHES OF NEW SNOW WILL BE OVER THE HIGH
TERRAIN OF THE NORTH AND WEST...WITH LITTLE CHANCE FOR A WHITE
CHRISTMAS ELSEWHERE.
FORCING FOR THE SNOW SHOWERS WILL BE WANING RAPIDLY IN THE
AFTERNOON AS A SHORTWAVE UPPER RIDGE HURRIES TO FILL IN BEHIND OUR
DEPARTING TROUGH.
HIGH TEMPS FROM NEAR 20 IN THE NORTH TO NEAR 49 IN THE SE WILL
REPRESENT A RETURN TO BELOW NORMAL TEMPS FOR THE REGION.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
UPPER LEVEL TROFFING WILL PERSIST THROUGH MUCH OF THE LONG TERM
PERIOD OVER THE EASTERN TWO THIRDS OF CONUS AS MODERATE TO STRONG
NORTHERN STREAM JET STREAM DIRECTS SEVERAL WAVES OF COLD AIR INTO
THE NORTHEASTERN U.S.
BRIEF PERIOD OF SHORT WAVE RIDGING ON WEDNESDAY WILL SUPPORT
STRONG SFC HIGH WITH A PERIOD OF QUIET WEATHER EXPECTED FOR
CHRISTMAS DAY. IN GENERA...MOST OF THE LONG TERM PERIOD SHOULD BE
RELATIVELY QUIET WEATHER-WISE DESPITE SEVERAL FRONTAL PASSAGES...AS
SYSTEMS WILL BE MOISTURE LIMITED AND NOT ABLE TO PRODUCE MUCH
PCPN.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
SOME ADJUSTMENTS MADE TO WINDS IN THE 21Z TAF PACKAGE.
RAIN HAS MOVED OUT OF THE SE PART OF THE CWA.
EARLIER DISCUSSION BELOW.
THE LOW IS NEAR NYC AND WILL CONTINUE PULLING
AWAY...LEAVING THE REGION IN A COOLER NW FLOW. THIS MEANS LOWER
CLOUDS ALONG WITH THE POTENTIAL FOR SNOW SHOWERS OVER THE HIGH
TERRAIN OF THE WEST AND NORTHWEST...WITH A RETURN TO VFR AT
CENTRAL AND EASTERN TERMINALS.
A STRONG UPPER LEVEL TROUGH WILL BE CROSSING THE AIRSPACE LATE
TONIGHT AND EARLY TUESDAY HELPING TO ENHANCE LAKE EFFECT/UPSLOPE
SNOW SHOWERS ACRS THE WESTERN AND NORTHER HIGH TERRAIN. LIGHT SNOW
SHOWERS AND BRIEF REDUCTIONS WILL BE POSSIBLE OVER CENTRAL
TERMINALS INTO TUESDAY AFTERNOON WHEN CONDITIONS SHOULD BEGIN
IMPROVING OVER ALL BUT NW PA AS A RIDGE OF HIGH PRESSURE BEGINS TO
BUILD BACK INTO THE AREA.
OUTLOOK...
WED...VFR HIGH PRES.
THU-FRI...OCNL SNOW SHOWERS/MVFR CIGS WEST. VFR CENTRAL AND
EASTERN AREAS.
SAT...NO SIG WX.
&&
.CLIMATE...
RECORD DAILY MAXIMUM TEMPERATURES WERE SET AT OUR OFFICIAL CLIMATE
SITES /HARRISBURG AND WILLIAMSPORT/ YESTERDAY. THERE WERE ALSO
SEVERAL "UNOFFICIAL" RECORD HIGHS SET AT NON-LCD SITES SUCH AS
ALTOONA AND BRADFORD.
A RECORD HIGH TEMPERATURE OF 70 DEGREES WAS SET AT HARRISBURG
YESTERDAY. THIS BROKE THE OLD RECORD HIGH OF 64 DEGREES SET BACK
IN 1949. A CONTINUOUS WEATHER RECORD HAS BEEN KEPT AT HARRISBURG
SINCE 1888.
A RECORD HIGH TEMPERATURE OF 64 DEGREES WAS SET AT
WILLIAMSPORT YESTERDAY. THIS BROKE THE OLD RECORD OF 60 DEGREES
SET BACK IN 1949. A CONTINUOUS WEATHER RECORD HAS BEEN KEPT AT
WILLIAMSPORT SINCE 1895.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...FITZGERALD/LA CORTE
NEAR TERM...FITZGERALD/LA CORTE
SHORT TERM...LA CORTE
LONG TERM...LAMBERT/GARTNER
AVIATION...LA CORTE/MARTIN
CLIMATE...