Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 12/25/13
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 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 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
942 PM CST TUE DEC 24 2013
.DISCUSSION...
810 PM CST
MADE SOME ADJUSTMENTS TO HOURLY TEMPERATURES TO ACCOUNT FOR A
QUICK FALL THIS EVENING...BUT WITH CLOUD COVER THICKENING AND
LOWERING AND WARM AIR ADVECTION STRENGTHENING WOULD ANTICIPATE
STEADY OR RISING TEMPS THE REMAINDER OF THE NIGHT.
FIRST BATCH OF SNOW OVER EASTERN IOWA LOOKS TO BE TAKING AIM ON
MOSTLY WISCONSIN AS VERY DRY AIR (RH AROUND 10% AT 850MB ON 00Z
DVN SOUNDING) IS RESULTING IN A BIG VIRGA STORM OVER NORTHERN
ILLINOIS AT THIS TIME. GUIDANCE STILL INDICATES THAT INCREASING
ASCENT AND CONTINUED MOISTENING FROM TOP DOWN WILL LIKELY RESULT
IN SATURATION AND SNOW DEVELOPING LATER THIS EVENING AND
PARTICULARLY AFTER MIDNIGHT. LATEST SUITE OF GUIDANCE HAS BEEN
INCREASINGLY PESSIMISTIC WITH RESPECT TO QPF AMOUNTS OVER OUR CWA
LATER TONIGHT INTO XMAS MORNING. WOULD NOT TAKE MUCH TO SQUEEZE
OUT A TENTH OF AN INCH OF SNOWFALL SO ONLY GOING TO SCALE BACK
POPS SLIGHTLY OVER CENTRAL AND SOUTHERN PORTIONS OF THE CWA WHILE
MAINTAINING CATEGORICAL. REGARDING SNOWFALL TOTALS...LATEST
GUIDANCE WOULD SUGGEST THAT EVEN AN INCH WOULD BE UNATTAINABLE
WITH THIS SYSTEM EXCEPT FOR FAR NORTHERN COUNTIES. NOT TERRIBLY
KEEN ON MAKING BIG CHANGES ON THIS SHIFT...SO GOING TO JUST GENTLY
SCALE BACK AMOUNTS A BIT RATHER THAN GO WITH WHAT IS LOOKING TO BE
THE MORE LIKELY SCENARIO WHICH IS MOST AREAS GETTING LITTLE MORE
THAN A DUSTING THROUGH CHRISTMAS MORNING.
SECOND SHORTWAVE PIVOTING AROUND THE POLAR VORTEX STILL LOOKS ON
TARGET TO BRING ANOTHER CHANCE OF SNOW SHOWERS LATER TOMORROW
AFTERNOON INTO TOMORROW EVENING...AGAIN ESPECIALLY NORTHERN CWA.
WILL LET THE NIGHT CREW HANDLE ANY GRID ADJUSTMENTS WITH THAT
SYSTEM.
IZZI
//PREV DISCUSSION...
225 PM CST
MAIN FORECAST CONCERNS WILL BE HONING IN ON A PAIR OF DISTURBANCES
BRINGING ACCUMULATING SNOW TONIGHT AND AGAIN DURING THE EVENING
TOMORROW...AS WELL AS TEMPERATURE TRENDS WITH NON-DIURNAL TEMPS
TONIGHT AND BITTER COLD RETURNING EARLY NEXT WEEK.
TODAY AND TONIGHT...
PAIR OF UPPER LEVEL DISTURBANCES EVIDENT ON WATER VAPOR IMAGERY THIS
AFTERNOON...THE FIRST TRANSLATING EAST ACROSS NEBRASKA...WHILE A
SECOND WAVE IS DIGGING ACROSS THE CANADIAN PRAIRIES. THE SOUTHERN
WAVE IS FORECAST TO LIFT ACROSS NRN IL/SRN WI OVERNIGHT. ISENTROPIC
ASCENT INCREASES AHEAD OF THE WAVE LATE THIS EVENING...WITH TOP DOWN
SATURATION GRADUALLY EATING AWAY AT THE VERY DRY AIR MASS CURRENTLY
IN PLACE. MOST MODELS INDICATE THAT PRECIP WILL BEGIN JUST BEFORE
MIDNIGHT OVER NORTH CENTRAL ILLINOIS AND INITIALLY WILL BE MAINLY
CONFINED TO THE TIER OR TWO OF COUNTIES NEAR THE STATE LINE WITH DRY
AIR WINNING OUT OVER AREAS FARTHER SOUTH. COLD TEMPERATURES WITH A
FAIRLY DEEP ISOTHERMAL LAYER THAT EXTEND FROM NEAR THE SURFACE TO
ABOUT 6KFT AND COINCIDES NEAR THE BASE OF THE DENDRITIC GROWTH ZONE
WILL HELP LEAD TO FLUFFIER THAN AVERAGE SNOW RATIOS...17-20:1
INITIALLY PER COBB OUTPUT. BETTER FORCING ASSOCIATED WITH THE UPPER
WAVE WILL BE RIGHT ON THE HEALS OF THIS FIRST WARM ADVECTION BURST
OF SNOW AND WILL LEAD TO SNOW SPREADING SOUTHEAST ACROSS THE
REMAINDER OF THE CWA...INCLUDING THE CHICAGO METRO AREA BY AROUND
3AM CST. DGZ NOT NEARLY AS DEEP OVER REMAINDER OF CWA WITH SLIGHTLY
WARMER TEMPS IN THE LOW/MID LEVELS AND A 2-3KFT DEEP DGZ NEAR THE
TOP OF THE SATURATED LAYER BUT COINCIDING WITH THE BETTER LIFT. THIS
WILL RESULT IN STILL DRY BUT CLOSER TO AVERAGE RATIOS OF 14-16:1.
WITH A BLEND OF NAM/GFS TIMING/QPF THIS EVENING...CONTINUE TO CALL
FOR 1-3 INCHES OF SNOW NORTH OF THE I-88 CORRIDOR...1 TO 2 INCHES
BETWEEN I-88 AND A PONTIAC TO VALPARAISO LINE...AND UP TO AN INCH
SOUTH OF THAT LINE.
IN ADDITION TO ACCUMULATING SNOWFALL...PRESSURE GRADIENT WILL
TIGHTEN BETWEEN A STRONG DEPARTING HIGH CURRENTLY OVERHEAD AND THE
APPROACHING FRONTAL TROUGH. THIS WILL RESULT IN BREEZY CONDITIONS
DEVELOPING OVERNIGHT WITH GUSTS INTO THE 20 TO 25 MPH RANGE. GIVEN
THE DRY NATURE OF THE SNOW...THIS WILL LIKELY CONTINUE TO BLOW SNOW
AROUND AFTER IT FALLS TO THE SURFACE. THE INCREASING SOUTHERLY FLOW
WILL ALSO LEAD TO WARMING TEMPERATURES THROUGH THE OVERNIGHT HOURS
WITH LOWS HAPPENING THIS EVENING. BY DAYBREAK TOMORROW...EXPECT
TEMPERATURES TO WARM INTO THE HIGH TEENS TO LOW 20S.
WEDNESDAY THROUGH FRIDAY...
AFOREMENTIONED NORTHERN WAVE WILL CONTINUE TO DIG INTO THE
MIDWEST...CARVING OUT A TROUGH THAT WILL SHIFT EAST ACROSS THE AREA
LATE WEDNESDAY EVENING. MOISTURE WITH THIS SECOND WAVE IS MORE
SHALLOW...AND WILL BE LOOKING AT CLOSER TO AVERAGE SNOW RATIOS.
QUICK HITTING SYSTEM MAY PRODUCE UP TO AN ADDITIONAL INCH NORTH OF
THE I-88 CORRIDOR WITH LITTLE IF ANY SNOW SOUTH. TEMPERATURES
WEDNESDAY NIGHT A BIT TRICKY...WITH SOME GUIDANCE POINTING AT MUCH
COOLER TEMPS THAN FORECAST...IN FACT SUB ZERO WEST OF THE FOX RIVER
VALLEY. HOWEVER...YET ANOTHER VORT LOBE WILL PIVOT ACROSS THE
AREA...AND WHILE DO NOT EXPECT ANY APPRECIABLE PRECIP WITH THIS
WAVE...IT SHOULD AT LEAST HOLD ONTO CLOUD COVER OVERNIGHT. WITH THE
RIDGE AXIS CENTERED OVER IOWA...DOES NOT APPEAR TO FAVOR A STRONG
RADIATIONAL COOLING SETUP AND WILL DISMISS THE COLDEST GUIDANCE.
RIDGE AXIS WILL ARRIVE OVERHEAD MIDDAY THURSDAY AND SHOULD KEEP
CONDITIONS DRY MOST OF THURSDAY AND FRIDAY. THOUGH AS THE SURFACE
RIDGE BREAKS DOWN LATER THURSDAY AND FRIDAY...WITH THE AREA UNDER
NORTHWEST FLOW WILL HAVE TO KEEP AN EYE ON THE POTENTIAL FOR A EVEN
A WEAK UPPER LEVEL DISTURBANCE TO SQUEEZE OUT SOME LIGHT SNOW...AS
SUGGESTED BY THE NAM. WILL KEEP "SILENT" 10-14 POPS IN THE MEANTIME.
SATURDAY THROUGH TUESDAY...
MODELS HAVE BEEN ADVERTISING A RELATIVELY STRONG CLIPPER SYSTEM TO
IMPACT PRIMARILY THE NORTHERN LAKES REGION OVER THE WEEKEND WITH
SMALL CHANCES FOR SNOW INTO NORTHERN ILLINOIS WITH A STRONG COLD
FRONT SWEEPING ACROSS THE AREA. AHEAD OF THE FRONT ON SATURDAY...
7-8C H85 THERMAL RIDGE WILL ADVECT OVERHEAD. EVEN WITH SOME SNOW ON
THE GROUND...LOCAL UPPER AIR CLIMATOLOGY SUGGESTS THAT MOST AREAS
SHOULD BE ABLE TO GET WELL INTO THE 30S...WITH LOW 40S EVEN A
POSSIBILITY...AN IDEA SUPPORTED BY A CONSENSUS MODEL BLEND. A STRONG
COLD FRONT WILL SWEEP ACROSS THE AREA SATURDAY NIGHT INTO SUNDAY
WITH H85 TEMPS PLUMMETING TO -17 TO -18C BY SUNDAY NIGHT. DEPENDING
ON THE EXACT TIMING THE OF THE FRONT...THIS COULD LEAD TO EARLY
MORNING LOWS SUNDAY WITH TEMPS FALLING THROUGH THE DAY AND
NIGHT...BOTTOMING OUT IN THE LOW SINGLE DIGITS OR EVEN BELOW ZERO
ONCE AGAIN...WITH THE COLD AIR MASS LINGERING INTO THE DAY TUESDAY.
BACK UNDER NORTHWEST FLOW ALOFT...THERE WILL BE PERIODIC CHANCES FOR
LIGHT SNOW EARLY NEXT WEEK.
DEUBELBEISS
&&
.AVIATION...UPDATED 03Z...
//ORD AND MDW CONCERNS...UPDATED 22Z...
* PERIOD OF LIGHT SNOW TONIGHT.
* IFR VSBY DURING SHORT PERIODS OF SOMEWHAT INCREASED SNOWFALL
RATE.
* MVFR CIG PERSISTING THROUGH TONIGHT AND THU.
* CHANCE OF ANOTHER PERIOD OF LIGHT SNOW LATE FRI AFTERNOON AND
FRI EVENING.
//DISCUSSION...UPDATED 00Z...
FOCUS IS ON PERIOD OF -SN TO OCCUR LATE TONIGHT INTO EARLY WED
MORNING...AND ON POTENTIAL FOR A SECOND PERIOD OF -SN DURING LATE
AFTERNOON AND EARLY EVENING WED NIGHT.
AN UPPER RIDGE WAS MOVING E...WITH ITS AXIS FROM FROM JAMES BAY
SSW TO IL EARLY THIS EVENING...WHILE AN UPPER TROUGH MOVED E TO
QUEBEC AND THE NORTHEASTERN CONUS. BEHIND THE UPPER RIDGE
CURRENTLY OVER OUR REGION IS ANOTHER UPPER TROUGH MOVING OVER
MANITOBA...THE NORTHERN PLAINS...CENTRAL HIGH PLAINS...AND
SOUTHERN ROCKIES. THE UPPER PATTERN IS TO CONTINUE TO BE
PROGRESSIVE WITH UPPER RIDGE AXIS CONTINUING E TO THE ONTARIO-
QUEBEC BORDER...LOWER GREAT LAKES AND UPPER OH VALLEY BY 12Z WED
WITH THE UPPER TROUGH TO OUR W MOVING TO WESTERN ONTARIO...THE
UPPER MS AND THE MID MO VALLEYS.
WITHIN THIS UPPER TROUGH MULTIPLE SHORT WAVES ARE SEEN IN IR AND
WATER VAPOR SATELLITE. THE STRONGEST WAS MOVE OVER SOUTHERN MN
WITH CLOUD TOPS STARTING TO GET COLDER. WHILE THE MAIN SHORT WAVE
TROUGH AND THE ASSOCIATED FORCING IS PROGGED TO MOVE ACROSS WI TO
LAKE MI OVERNIGHT...THERE WILL BE AN AREA OF DEEP ISENTROPIC
ASCENT SPREADING FROM IA OVER NORTHERN AND E CENTRAL IL DURING THE
LATE EVENING AND OVERNIGHT. RADARS SHOWING RETURNS SPREADING INTO
N CENTRAL AND E CENTRAL IL BUT METARS BENEATH THE ECHOES NOT
REPORTING ANY SN...JUST CLOUDS IN THE 060-120 RANGE AS THE MID
LEVEL WARM AIR ADVECTION INCREASES. AS THE LOWER LEVEL FLOW
CONTINUES TO INCREASE TONIGHT SO DOES MOISTURE ADVECTION FROM THE
SOUTHERN PLAINS NE ACROSS THE OZARKS AND MID MS VALLEY.
LATEST MODEL PROGS AVAILABLE AT THIS TIME KEEP THE BULK OF THEIR
QPF UP IN WI WITH LIGHT AMOUNTS ACROSS THE LOCAL AREA OVERNIGHT-
EARLY MON MORNING. STILL EXPECT A PERIOD OF -SN LOCALLY...WITH A
COUPLE HOUR PERIOD OF SOMEWHAT HIGHER SNOWFALL RATES. TOTAL
PRECIP AMOUNTS FROM MODELS LIGHT BUT THE SNOW WILL BE OF A FAIRLY
HIGH SNOW TO LIQUID RATIO SO STILL MAY SEE SNOWFALL OF 1-2 IN.
THE -SN WILL SHOULD QUICKLY END SOON AFTER SUNRISE AS THE SHORT
WAVE TROUGH QUICKLY PROGRESSES EASTWARD FROM OVER THE LOCAL AREA.
HOWEVER...JUST UPSTREAM OF THE SHORT WAVE TO MOVE OVER US
OVERNIGHT IS ANOTHER DISTURBANCE CURRENTLY DROPPING SE OVER ND.
THIS SECOND SHORT WAVE TROUGH IS PROGGED MOVE FROM THE MN
ARROWHEAD...FAR NW WI...THE UPPER MS VALLEY AND CENTRAL IL TO SW
WI...E CENTRAL IA AND FAR W CENTRAL IL DURING THE 25/18Z-26/00Z
PERIOD...CONTINUING E ACROSS THE LOCAL AREA WED NIGHT. MOISTURE IS
LIMITED WITH THIS DISTURBANCE...ESPECIALLY IN THE MID AND UPPER
LEVELS WHERE THE MORE SIGNIFICANT UPWARD MOTION IS TO BE OCCURRING
AS THIS NEXT SHORT WAVE TROUGH APPROACHES. BY 026/00Z MODELS
SHOWING UVV LOWERING INTO THE TOP PORTION OF THE MOIST LOWER
LEVELS. WITH THE COLD AIR THE FAVORED SNOW GROWTH TEMPERATURES ARE
ONLY 060-070 AGL SO DO EXPECT ANOTHER SHORT PERIOD OF VERY LIGHT
SNOW STARTING POSSIBLY AS EARLY AS LATE WED AFTERNOON...MORE
LIKELY THE FIRST HALF OF WED EVENING.
LIGHT WINDS WILL BE PICKING UP DURING THE NIGHT OUT OF THE SSE-S
AND THEN THE SSW-SW AS SURFACE PRESSURE FALLS OVER WESTERN
ONTARIO AND THE UPPER MIDWEST SHIFT TO THE E IN RESPONSE TO THE
APPROACH OF THE SHORT WAVE TROUGH. WHILE INCREASING THEY ARE ONLY
EXPECTED TO GUST INTO THE 20-25KT RANGE DURING THE OVERNIGHT.
THEY SHOULD THEN DIMINISH DURING THE MORNING AS THE TIGHTER
SURFACE PRESSURE GRADIENT AND PRESSURE FALLS MOVE OFF TO THE E.
TRS
//ORD AND MDW CONFIDENCE...UPDATED 03Z...
* HIGH IN LIGHT SNOW OCCURRING TONIGHT...AS WELL AS IN GENERAL
VSBY TRENDS.
* MEDIUM IN TIMING OF SHORT PERIOD OF SLIGHTLY INCREASED SNOWFALL
RATE...AND IN END TIME OF ANY ACCUMULATING LIGHT SNOW.
* MEDIUM IN MVFR CIGS PERSISTING THROUGHOUT THU.
* HIGH IN ANOTHER PERIOD OF LIGHT ACCUMULATING SNOW IN THE AREA
LATE AFTERNOON AND EVENING WED...BUT LOW ON IF IT WILL REACH
FAR ENOUGH S TO AFFECT IMMEDIATE ORD AND/OR MDW AREAS.
TRS
//OUTLOOK FOR ORD/MDW FOR 12Z THU-12Z TUE...UPDATED 00Z...
THU THROUGH MON...VFR. SLIGHT CHANCE -SN ON SUN AS WELL AS MON
NIGHT.
&&
.MARINE...
215 PM CST
MAIN CONCERNS FOR THE LAKE ARE GALES DEVELOPING THIS EVENING AND
CONTINUE THROUGH WEDNESDAY MORNING.
HAZARDOUS WAVES/WINDS WILL ALSO DEVELOP FOR THE NEARSHORE WATERS
AND MAY ALSO SEE OCCASIONAL GALE FORCE GUSTS IN THE NEARSHORE
WATERS OVERNIGHT THRU DAYBREAK WEDNESDAY.
SFC RIDGE OVER THE OHIO VALLEY WILL CONTINUE TO DRIFT EAST
TONIGHT...WITH A TIGHTENING GRADIENT ALONG THE WESTERN EDGE. THIS
TIGHT GRADIENT WILL SLIDE OVER THE LAKE TONIGHT...PRODUCING
SOUTH/SOUTHWEST GALES BETWEEN 35-40KT OVERNIGHT. THE GRADIENT
CONTINUES TO SLIDE EAST WITH THE ARRIVAL OF A CLIPPER LOW
PRESSURE. THIS CLIPPER WILL ALLOW THE WINDS TO BECOME
WESTERLY...AND SHOULD SEE GALES COME TO AN END BY MID-MORNING WED.
HOWEVER THE GRADIENT WILL REMAIN RELATIVELY STRONG AND PRODUCE
WINDS TO 30KT THRU MIDDAY WED BEFORE DIMINISHING TO 15 TO 25 KT BY
WED NIGHT.
THE NEXT WEATHER SYSTEM TO BRING A STRONG GRADIENT TO THE LAKE
WILL ARRIVE SAT...AND LIKELY PRODUCE WINDS TO 30KT. IT IS POSSIBLE
A FEW GUSTS TO GALE FORCE MAY OCCUR SAT.
THEN ANOTHER STRONG RIDGE OF HIGH PRESSURE WILL SLIDE SOUTH FROM
CENTRAL CANADA FOR THE SECOND HALF OF THE WEEKEND AND MAY BRING A
TIGHT GRADIENT TO THE LAKE.
BEACHLER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 AM WEDNESDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 10 PM WEDNESDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
[top]
Area Forecast Discussion
National Weather Service Lincoln IL
859 PM CST Tue Dec 24 2013
.DISCUSSION...
ISSUED 859 PM CST Tue Dec 24 2013
Plan to update forecast to reduce snow chances tonight and
Christmas morning. WAA/isentropic lift ahead of main clipper wave
is rapidly shifting east of the area. This forcing has done little
more than develop a deck of mid clouds locally. Forcing with the
upper wave itself is expected to arrive overnight into the morning
hours. There is currently very little snow occurring with the wave
right now, at least with the portion of the wave likely to impact
central Illinois, and the latest HRRR and 00Z NAM have trended
drier.
Low temperatures for the night have likely already been attained,
with good southerly flow helping temperatures to be steady or
slowly rise through the night. This portion and the remainder of
the short term forecast is in good shape and only minor tweaks are
needed for the latest hourly trends.
Bak
&&
.AVIATION...
ISSUED 555 PM CST Tue Dec 24 2013
Clipper still on track to cross the Midwest tonight/early
Christmas day. Recent model trends suggest the chances for
significant snowfall impacting the terminals is diminishing.
Following this new thinking, have removed IFR conditions in snow
from the terminals. Current plan is for cigs and possibly vsbys to
fall to MVFR levels as the clipper passes by after midnight
tonight. Still keeping mvfr cigs through the daytime hours
Christmas Day, but some models are starting to suggest the cigs
will improve to vfr.
Bak
&&
.PREV DISCUSSION...
ISSUED 250 PM CST Tue Dec 24 2013
Very few changes needed to the forecast as the models remain
fairly consistent and in pretty good agreement throughout much of
the forecast period. Periodic shots of cold air with no major
storms, followed by brief warm-ups will be the main weather trend
for the upcoming week.
SHORT TERM...Tonight through Thursday
High pressure, which brought sub-zero readings to parts of central
Illinois this morning, was centered in southwest IN early this
afternoon. A southerly wind flow has already developed in
Illinois, and this will continue to increase through the evening
and overnight. The result will be slowly rising temperatures
through the night and into Christmas morning.
A clipper system in the northern Plains and its associated weak
surface low in north central Nebraska will shift to the ESE
tonight, spreading light snow into west central IL mainly after
midnight. The axis of the light snow will shift east of the I-55
corridor around daybreak, with lingering flurries to the west. By
late morning the snow should come to an end in much of east
central Illinois, with some lingering flurries from PIA-DEC-MTO-
Robinson. Most areas can expect around 0.5" or less of snow,
except in locations from Canton to just north of Bloomington where
1.0 to 1.5 inches are likely. The snow should be rather fluffy and
will blow around quite a bit with a southwest wind of 10 to 15 mph.
Partial clearing is then expected in the wake of the clipper
system with temperatures in the lower to middle 30s. Another
clipper system will follow on the heels of the first one later on
Christmas Day, but the measurable snow should stay well north of
central IL. This system will bring central Illinois a glancing
blow of colder air, so highs on Thursday will be a bit cooler
along and north of I-74. The rest of central and SE IL can expect
highs Thursday to be very similar to Wednesday`s.
LONG TERM...Friday through Tuesday
Overall, the medium and long range models are in pretty good
agreement with the mean upper level flow from the weekend into
early next week. By Friday, the upper level trough axis in the
eastern U.S. will breakdown and become flatter/more westerly. This
will allow temperatures to warm slightly Friday, with a nice warm-
up well into the 40s expected Saturday. Locations north of I-74,
however, may have some lingering snow which could keep
temperatures down in the upper 30s.
Both the GFS and European agree that the main longwave trough will
re-establish itself in the eastern U.S. by early next week.
However, they arrive at the solution differently - particularly
Sunday into Monday. The GFS is weaker with the trough early on,
and redevelops the longwave gradually. The European is stronger and
sharper with the shortwaves that carve out the new trough, which
results in a solution of light snow Sunday in the upper Midwest
and northern IL. Low level moisture will be quite low, and due to
the lack of persistence in the European model with this scenario
will hold of on mentionable PoPs for now, and keep the forecast in
the slight chance category.
Both models do agree, however, that another shot of very cold air
is in store for the Midwest by late Sunday and lasting into New
Year`s Eve with lows in the single digits to lower teens, and
highs in the teens to lower 20s.
Miller
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
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.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
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.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
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 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 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
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 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 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
609 PM EST TUE DEC 24 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 438 PM EST TUE DEC 24 2013
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOWS SHRTWV RDG AXIS
MOVING INTO THE WRN LKS BTWN DEPARTING TROF IN THE SE GRT LKS
RESPONSIBLE FOR LES THE PAST FEW DAYS AND A PAIR OF SHRTWVS DIGGING
SEWD THRU SCENTRAL CANADA/THE NRN ROCKIES E OF MEAN RDG NEAR THE W
COAST. WITH SFC HI PRES BLDG ACRS THE AREA...LINGERING LES NEAR LK
SUP HAS DIMINISHED AND PUSHED INTO THE OPEN WATERS AS THE FLOW IS
SHIFTING TO THE SSW IN ADVANCE OF THE SFC LO PRES TROF IN THE NRN
PLAINS ASSOCIATED WITH THE TWO CLIPPER SHRTWVS. THE 12Z INL/MPX
RAOBS SHOWED A VERY DRY AIRMASS WITH PWATS UNDER 0.10 INCH...SO
SKIES ARE TURNING MOSUNNY AT MOST PLACES AS THE SSW FLOW SHIFTS
LINGERING LO CLDS BACK OUT OVER LK SUP. MID CLDS IN ADVANCE OF
APRCHG CLIPPER SHRTWVS/SFC TROF ARE PUSHING EWD THRU MN...WITH SN
FALLING OVER NW MN AND THE ERN DAKOTAS. ALTHOUGH THIS SN HAS BEEN
MDT AT SOME PLACES UNDER THE SHARPER H85-5 QVECTOR CVNGC...THE
COVERAGE APPEARS TO BE LIMITED BY ABSENCE OF SGNFT MSTR INFLOW.
MAIN FCST CONCERNS IN THE SHORT TERM ARE EXPECTED POPS/SN AMOUNTS
LATE TNGT AND XMAS MRNG ASSOCIATED WITH UPSTREAM CLIPPER SHRTWVS AND
GOING WINTER STORM WATCH OVER THE ERN CWA/NEED FOR ANY NEW HEADLINES.
TNGT INTO XMAS DAY...UPR TROF TO THE NW IS FCST TO SHIFT TO THE SE
AND STRETCH FM NW ONTARIO THRU MN AND INTO THE CENTRAL PLAINS BY 12Z
WED. MODELS SHOW PCPN IN ADVANCE OF THIS TROF ARRIVING OVER THE WRN
CWA LATE THIS EVNG AND PUSHING TO THE E...WITH A 6-9 PERIOD OF SN AT
MOST LOCATIONS BEFORE THE SN DIMINISHES OVER THE W 09-12Z WED AND BY
ABOUT 18Z WED OVER THE ERN CWA FOLLOWING DEPARTURE OF DEEP LYR
QVECTOR CNVGC. MAIN NEGATIVES FOR SGNFT SN FALL INCLUDE FCST SHARPER
H85-5 QVECTOR CNVGC/SHARPER H7 UVV ASSOCIATED WITH INCOMING OUT OF
PHASE SHRTWVS FOCUSING TO THE S OF UPR MI... LACK OF SGNFT MSTR
INFLOW WITH ONLY ABOUT 1.5-2 G/KG SPECIFIC HUMIDITY NEAR H7...AND
LIMITED RESIDENCE OF TIME OF PCPN. ONE FACTOR IN FAVOR OF SOMEWHAT
HIER SN AMOUNTS IS FCST DEEP DGZ THAT MAY BOOST SN/WATER RATIOS AS
HI AS 20-25:1. CONSIDERING MODEL QPF 0.05-0.15 INCH...EXPECT 1 TO 3
INCHES OF SN. THE ONE EXCEPTION WL BE OVER THE ERN CWA DOWNWIND OF
LK MI...WHERE INCRSG SSW FLOW UP THE LENGTH OF LK MI IN THE PRESENCE
OF DEEP MSTR/H85 TEMPS ARND -15C WL BRING A PERIOD OF HEAVIER LK
ENHANCED SN. PRESENCE OF LINGERING BAND IN NRN LK MI AS SHOWN ON
RECENT STLT IMAGERY EARLY THIS AFTN INCREASES CONFIDENCE IN THIS
FCST. BULK OF HIER RES MODELS SHOW THE HEAVIER LES BAND IMPACTING
FAR SE SCHOOLCRAFT COUNTY/SRN LUCE COUNTY IN THE 09Z-15Z WED TIME
FRAME. WITH MODEL QPF RANGING FM 0.25 INCH TO AS MUCH AS 0.40 INCH
AND DEEP DGZ SHOWN ON THE FCST SDNGS...EXPECT AT LEAST A HI END ADVY
SNFALL IN THIS AREA. FCST SDNGS ALSO SHOW A PERIOD OF NEARLY
UNIDIRECTIONAL SSW FLOW WITHIN THE MIXED LYR FOR A FEW HRS DURING
TIME OF PEAK SN INTENSITY. GIVEN THESE FVRBL CONDITIONS...OPTED TO
UPGRADE WATCH TO A WRNG FOR LUCE COUNTY...WHERE HEAVIER LES BAND IS
MOST LIKELY TO RESIDE THE LONGEST AND DROP UP TO 9 TO PERHAPS 10
INCHES ALONG M-28 E OF ERY. WENT WITH AN ADVY FOR SCHOOLCRAFT COUNTY
WITH POTENTIAL FOR SOME LK ENHANCEMENT...ESPECIALLY E OF SENEY AND
MANISTIQUE. AS FOR TEMPS...ARRIVAL OF THICKER CLDS/STEADY S WIND WL
ALLOW FOR ONLY A RELATIVELY SMALL TEMP DIP EARLY OVER THE W HALF.
BUT TO THE E...EXPECT TEMPS TO FALL QUICKLY OVER THE INTERIOR ERN
CWA THIS EVNG BEFORE THE CLDS AND STEADY S WINDS ARRIVE LATER.
LATER ON XMAS DAY...AS THE UPR TROF AND SFC REFLECTION SHIFT SLOWLY
THRU THE UPR GREAT LKS...THE LLVL FLOW IS PROGGED TO VEER TOWARD THE
W. THIS WSHFT TO A MORE WSW DIRECTION WL END THE THREAT OF LK
ENHANCED SHSN OVER THE E BY EARLY AFTN BUT CAUSE SOME LES TO DVLP
OVER THE W IN THE AFTN AS H85 TEMPS DIP BACK NEAR -18C BY 00Z THU.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 438 PM EST TUE DEC 24 2013
WEDNESDAY NIGHT...LOW LEVEL CONV ALONG A COLD FRONT AND 850
MB TEMPS DROPPING FROM -15C TO -19C WILL BRING AN INCREASE IN LES
INTO NORTHWEST UPPER MICHIGAN WED EVENING AND OVER ERN CWA
OVERNIGHT. EVEN WITH A FAVORABLE PLACEMENT OF THE DGZ IN THE
CONVECTIVE LAYER GIVING SLR VALUES NEAR 25/1...INVERSION HEIGHTS
NEAR 6K FT AND STEADILY VEERING WINDS SHOULD KEEP ACCUMULATIONS IN
THE 2 TO 4 INCH RANGE...WITH THE GREATEST AMOUNTS IN THE HIGHER
TERRAIN FROM CALUMET TO TWIN LAKES AND NORTH OF M-28 EAST OF
MUNISING.
THU INTO THU NIGHT...NW FLOW LES WILL GRADUALLY DIMINISH AS A WEAK
SFC RIDGE BUILDS FROM THE UPPER MS VALLEY INTO THE WRN LAKES
BRINGING BACKING WINDS AND LOWERING INVERSION HEIGHTS. THE STRONGEST
FORCING AND MOST FAVORABLE WAA/ISENTROPIC LIFT ASSOCIATED WITH A
WEAK CLIPPER SHORTWAVE TROUGH IS EXPECTED TO REMAIN SOUTH OF THE
UPPER MICHIGAN.
FRI...THE ECMWF WAS MORE AGGRESSIVE WITH POTENTIAL FOR SOME LIGHT
SNOW BY LATE FRI WITH THE WAA/ISENTROPIC LIFT PATTERN DEVELOPING
AHEAD OF THE NEXT CLIPPER SHRTWV AND SFC LOW MOVING TOWARD NW
ONTARIO COMPARED TO THE GFS/GEM. WITH LOW CONFIDENCE IN ANY
PCPN...ONLY SLIGHT/CHANCE POPS WERE INCLUDED...MAINLY OVER THE EAST.
SAT INTO SAT NIGHT...A BRIEF WARMUP IS EXPECTED SATURDAY AS UPPER MI
WILL BE IN THE WARMER SECTOR AHEAD OF THE NEXT LOW. TEMPS SHOULD
CLIMB ABOVE NORMAL WITH HIGHS AROUND 30. MODEL DIFFERENCES WERE EVEN
GREATER BY SATURDAY NIGHT...AS THE ECMWF WAS SLOWER/DEEPER WITH
SHRTWV AND SFC LOW MOVING THROUGH THE NRN GREAT LAKES. REGARDLESS OF
MODEL DIFFERENCES...A COLD FRONT MOVING THROUGH WITH WINDS VEERING
SHARPLY TO THE NNW SHOULD BRING LES OR LAKE ENHANCED SNOW INTO NRN
UPPER SAT NIGHT.
SUN-TUE...ANOTHER VERY COLD ARCTIC AIRMASS WILL DOMINATE THE REGION
THROUGH THE PERIOD WITH LES EXPECTED FOR NW WIND FAVORED SNOWBELTS.
WIND CHILL VALUES NEAR ADVISORY WILL BE POSSIBLE OVER THE WEST HALF
BOTH EARLY MONDAY AND TUESDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 608 PM EST TUE DEC 24 2013
AS THE PRES GRADIENT OVER UPR MI TIGHTENS BTWN A DEPARTING SFC HI
PRES RDG AND AN APRCHG LO PRES TROF...EXPECT GUSTY S WINDS TO DVLP
THIS EVENING AT THE MORE EXPOSED IWD/SAW LOCATIONS. VFR CONDITIONS
WL GIVE WAY TO IFR CONDITIONS BY LATE EVNG AS SN IN ADVANCE OF THE
TROF MOVES W-E INTO UPR MI. EVEN AFTER THE SN DIMINISHES W-E BY
SUNRISE ON WED...MVFR SC CIGS WL LINGER. AS THE WEAKER FLOW VEERS
TOWARD THE W LATER ON WED MRNG...MORE SHSN/IFR VSBYS MAY IMPACT CMX
LATE IN THE TAF PERIOD.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 438 PM EST TUE DEC 24 2013
AS THE PRES GRADIENT TIGHTENS OVER LAKE SUPERIOR THIS EVENING
BETWEEN DEPARTING SURFACE HI PRES RIDGE AND AN APPROACHING LO PRES
TROF...OPTED TO MAINTAIN GOING GALE WARNING FOR THE ECENTRAL
PORTIONS OF THE LAKE. AWAY FROM THIS FAVORED AREA...SOME GALE FORCE
GUSTS WILL BE POSSIBLE. CLOSER APPROACH AND THEN PASSAGE OF LO PRES
TROF AND WEAKER GRADIENT ON WED WILL CAUSE THE GALES TO DIMINISH AS
THE WINDS VEER TOWARD THE W-NW. NORTHWEST TO NORTH GALES WILL AGAIN
BE POSSIBLE SATURDAY NIGHT BEHIND AN ARCTIC COLD FRONT. HEAVY
FREEZING SPRAY IS ALSO EXPECTED INTO EARLY NEXT WEEK.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY FROM 1 AM TO 10 AM EST WEDNESDAY FOR
MIZ014-085.
WINTER STORM WARNING FROM 1 AM TO 1 PM EST WEDNESDAY FOR MIZ007.
LAKE SUPERIOR...
GALE WARNING FROM 11 PM THIS EVENING TO 7 AM EST WEDNESDAY FOR
LSZ266.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...JLB
AVIATION...07
MARINE...KC
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 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 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
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 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 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...UPDATED
NWS BILLINGS MT
840 PM MST TUE DEC 24 2013
.UPDATE...
ONLY MINOR CHANGES ARE IN THE WORKS FOR THE OVERNIGHT FORECAST. WE
WILL ACTUALLY INCREASE EXPECTED LOWS A BIT IN MANY AREAS SINCE THE
WESTERLY LOW-LEVEL FLOW MAY KEEP ENOUGH TURBULENT LOW-LEVEL MIXING
GOING TO NEGATE ANY BIG FALLS...ESPECIALLY SINCE SNOWMELT HAS BEEN
OCCURRING TODAY. ONE EXCEPTION WILL BE AROUND SHERIDAN...WHERE THE
WINDS WILL BE LIGHT...AND THUS TEMPERATURES SHOULD FALL AS PLANNED
ONCE CLOUDS DECREASE A BIT. OTHERWISE...ONLY SMALL ADJUSTMENTS ARE
BEING MADE TO THE GRIDDED FORECAST. SCHULTZ
&&
.SHORT TERM...VALID FOR WED AND THU...
BIGGEST CONCERN FOR THIS FORECAST PACKAGE WILL BE WINDS.
NORTHWEST FLOW WILL BE PRESENT OVER THE AREA BUT THE SHORTWAVES
THAT MOVES THROUGH WILL BE WEAK AND THE ATMOSPHERE IS NOT EXPECTED
TO BE OVERLY MOIST. SO WILL LEAVE POPS OUT. TEMPERATURES WILL BE
MILD WITH 850MB TEMPERATURES ABOVE ZERO. NOW TO WINDS.
WINDS HAVE INCREASED FROM BIG TIMBER TO HARLOWTON THIS AFTERNOON
WITH SOME GUSTS TO 50 MPH. GRADIENT HAS TIGHTENED UP BUT WAS NOT
OVERLY TIGHT. MODELS SLACKEN THE GRADIENT SOME TONIGHT AND WOULD
THUS EXPECT THE WINDS TO DECREASE SOME. THE HRRR MODEL DID GRAB
ONTO THESE STRONGER WINDS THIS AFTERNOON AND DECREASES THE WINDS
THIS EVENING. SO WILL NOT ISSUE ANY HIGHLIGHTS AT THIS TIME.
THE GRADIENT TIGHTENS UP FURTHER WEDNESDAY NIGHT AND TURNS MORE
PERPENDICULAR TO THE UPPER YELLOWSTONE AND UPPER STILLWATER RIVER
VALLEYS. THIS WILL CAUSE SOUTHWEST WINDS TO CRANK UP AGAIN AT
LIVINGSTON AND NYE. HAVE BUMPED WINDS UP INTO ADVISORY CRITERIA.
WILL NOT ISSUE WIND HIGHLIGHTS FOR THIS YET AS WOULD LIKE TO SEE
SOME MODEL AND GUIDANCE PERSISTENCE ON THIS EVENT. WILL ISSUE A
HWO AND PUT A GRAPHIC ON THE WEB PAGE FOR THE WINDS. TWH
.LONG TERM...VALID FOR FRI...SAT...SUN...MON...TUE...
MODELS REMAIN GOOD AGREEMENT THROUGH THE EXTENDED PERIOD. A FAST
NORTHWEST FLOW ALOFT WILL BE OVER THE FORECAST AREA THROUGH THE
MAJORITY OF THE PERIOD AS A HIGH PRESSURE RIDGE AXIS WILL REMAIN
OVER THE PACIFIC NORTHWEST. FRIDAY...HIGH PRESSURE RIDGING AND
RISING HEIGHTS WILL BE OVER THE FORECAST AREA RESULTING IN DRY
CONDITIONS AND ABOVE NORMAL TEMPERATURES. SURFACE LOW PRESSURE
ACROSS SOUTHERN CANADA COMBINED WITH HIGH PRESSURE ACROSS IDAHO
WILL SET UP LEE-SIDE TROUGHING ACROSS OUR AREA RESULTING IN
CONTINUED WINDY CONDITIONS FOR THE BEARTOOTH/ABSAROKA FOOTHILLS
LOCATIONS.
ANOTHER FAST MOVING DISTURBANCE...AN ALBERTA CLIPPER
SYSTEM...WILL DROP SOUTHEAST OUT OF CANADA LATE FRIDAY NIGHT INTO
SATURDAY NIGHT BRINGING ANOTHER ARCTIC FRONT AND A GOOD CHANCE FOR
SNOW ACROSS THE AREA ESPECIALLY SATURDAY AFTERNOON AND EVENING.
DYNAMICS ARE DECENT WITH THIS SYSTEM AND MODELS SHOW A GOOD
FRONTOGENESIS BAND ACROSS THE AREA ESPECIALLY THE
BEARTOOTH/ABSAROKA FOOTHILLS AREA. ALTHOUGH LATEST MODELS HAVE
SHOWN THIS SYSTEM TO BE WEAKENING A BIT. HOWEVER...GIVEN UNSTABLE
NORTHWEST FLOW ALOFT...CAN NOT RULE OUT THIS SYSTEM BEING STRONGER
THAN WHAT MODELS CURRENTLY SHOW. 850MB TEMPERATURES ARE A BIT
WARMER BUT STILL AROUND -15C BY SUNDAY MORNING. AS A
RESULT...EXPECT LOWS SUNDAY MORNING IN THE SINGLE DIGITS AND TEENS
WITH HIGHS SUNDAY IN THE 20S WEST WITH TEENS ACROSS THE EAST. WEAK
DOWNSLOPE FLOW RETURNS FOR MONDAY MODERATING TEMPERATURES BACK
CLOSER TO NORMAL. HOOLEY
&&
.AVIATION...
SKIES WILL BE CLEAR TO PARTLY CLOUDY THROUGHOUT THE NIGHT WITH
VFR CONDITIONS PREVAILING. NO SIGNIFICANT AVIATION HAZARDS ARE
EXPECTED. WINDS ARE EXPECTED TO INCREASE AGAIN AT KLVM WEDNESDAY.
BT
&&
.PRELIMINARY POINT TEMP/POPS...
WED THU FRI SAT SUN MON TUE
-----------------------------------------------------------
BIL 020/041 025/045 031/046 028/036 017/024 014/034 019/035
00/N 10/N 00/N 02/J 32/J 21/B 11/B
LVM 021/041 026/046 032/047 025/035 014/025 015/034 022/035
00/N 10/N 00/N 12/J 23/J 21/N 11/B
HDN 017/036 011/044 018/045 024/034 011/022 007/032 010/033
00/N 10/N 00/U 02/J 32/J 21/B 11/B
MLS 016/031 013/039 023/041 023/030 007/015 901/027 003/028
00/B 10/B 00/U 12/J 32/J 21/E 12/J
4BQ 015/033 014/042 023/044 023/033 008/019 001/029 006/032
10/B 10/B 00/U 02/J 32/J 21/B 11/B
BHK 015/030 011/038 022/040 022/027 003/016 903/022 005/025
10/B 10/B 00/B 12/J 32/J 21/E 22/J
SHR 012/037 015/046 021/046 023/036 013/022 008/034 013/035
00/B 00/B 00/U 02/J 32/J 21/B 11/B
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
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 CLEVELAND OH
646 PM EST TUE DEC 24 2013
.SYNOPSIS...
HIGH PRESSURE FROM THE CENTRAL LAKES TO THE LOWER OHIO VALLEY WILL
MOVE TO THE MIDDLE ATLANTIC STATES ON CHRISTMAS DAY. A COLD FRONT
WILL MOVE EAST ACROSS THE AREA THURSDAY. HIGH PRESSURE WILL BUILD
OVER THE REGION THURSDAY NIGHT. THE HIGH PRESSURE AREA WILL DRIFT
SOUTH TO THE TENNESSEE VALLEY BY SATURDAY AND ALLOW FOR MODERATING
TEMPERATURES.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
LAKE EFFECT SNOW CONTINUES TO DECREASE IN COVERAGE BUT IT APPEARS
IT WILL KEEP ACCUMULATING IN THE ADVISORY AND WARNING AREAS THROUGH
AROUND 03Z. ADDITIONAL AMOUNTS SHOULD BE UNDER AN INCH. A FEW
FLURRIES WILL THEN LINGER UNTIL AROUND 06Z. STILL APPEARS THAT WE
WILL BE ABLE TO LET THE HEADLINES END AT 10 PM.
OTHERWISE WE WILL CONTINUE TO MONITOR THE THINNING OF THE CLOUD
COVER ACROSS NORTHERN OHIO. HOW LONG A PERIOD OF PARTLY CLOUDY
SKIES WILL HAVE A HUGE IMPACT ON LOW TEMPERATURES BEFORE HIGH
CLOUDS RETURN TO THE WEST AFTER MIDNIGHT.
PREVIOUS DISCUSSION...
LAKE EFFECT SNOWS ARE WINDING DOWN THIS AFTERNOON AS THE UPPER
TROUGH MOVES EAST THE AREA AND THE INVERSION LOWERS ACROSS THE
REGION. THE FLOW HAS VEERED TO NORTHWEST DECREASING THE FETCH
ACROSS LAKE ERIE. VISIBLE IMAGERY SHOWS CUMULUS CLOUDS GRADUALLY
CLEARING OVER THE WESTERN SECTION OF THE LAKE. LAKE EFFECT BANDS
SHOULD CONTINUE TO DIMINISH. ONE TO TWO MORE INCHES OF SNOW ARE
POSSIBLE THIS EVENING OVER FAR NE OHIO AND NW PA SO WILL CONTINUE
THE LAKE EFFECT HEADLINES WITH NO CHANGES. WILL KEEP LIKELY POPS
IN NW PA FOR THIS EVENING WITH DRY CONDITIONS OVER THE WESTERN 2/3
OF THE FORECAST AREA.
WITH FRESH SNOW COVER EAST OF CLE AND SOME CLEARING EXPECTED ALONG
WITH LIGHT WINDS...SOME RADIATIONAL COOLING IS EXPECTED
ESPECIALLY IN GEAUGA COUNTY. THE HRRR MODEL SURFACE TEMPERATURES
DROP INTO THE SINGLE DIGITS IN THIS AREA AND THIS SEEMS VERY
REASONABLE. ELSEWHERE SLIGHTLY WARMER CONDITIONS ARE EXPECTED
GIVEN SLIGHTLY MORE WIND AND EITHER SLOWER CLEARING THIS EVENING
OR AN INCREASE IN CLOUDS AFTER MIDNIGHT. STILL READING WILL BE
RATHER COLD AND BE AROUND 10.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY NIGHT/...
ANOTHER SHORT WAVE WILL MOVE EAST ACROSS THE GREAT LAKES CHRISTMAS
DAY AND PRODUCE MODEST ISENTROPIC LIFT ACROSS THE AREA. THE
AIRMASS IS QUITE DRY SO LITTLE SNOWFALL IS EXPECTED AND WILL BE
MAINLY NEAR LAKE ERIE WITH LITTLE MORE THAN A DUSTING.
TEMPERATURES WILL MODERATE TO THE MID TO UPPER 20S.
ANOTHER IMPULSE WILL DEEPEN THE TROUGH WEDNESDAY EVENING AND EARLY
THURSDAY WITH A COLD FRONTAL PASSAGE TOWARD MORNING. THE LOW LEVEL
FLOW VEERS TO A MORE WESTERLY DIRECTION WITH 850 MB TEMPERATURES
COOLING TO NEAR -12C SO SOME LAKE EFFECT/ENHANCED SNOW IS EXPECTED
IN THE SNOWBELT THURSDAY. THE FLOW WILL BACK TO A SOUTHWESTERLY
DIRECTION THURSDAY NIGHT ALONG WITH WARMING CONDITIONS SO ANY LAKE
EFFECT SNOWBANDS WILL SHIFT OFFSHORE AND DIMINISH.
FAIR MODERATING CONDITIONS ARE EXPECTED FRIDAY AS 850 MB
TEMPERATURES WARM TO NEAR 0C AS A SOUTHWESTERLY FLOW DEVELOPS.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
DRY WEATHER IS EXPECTED ON SATURDAY AS A FRONT APPROACHES FOR
SUNDAY. THE AMOUNT OF MOISTURE ASSOCIATED WITH THE FRONT IS NOT THAT
IMPRESSIVE SO WILL CONTINUE CHANCE POPS ON SUNDAY INTO SUNDAY NIGHT.
PRECIPITATION TYPE IS IN QUESTION. THE ECMWF IS A LITTLE WARMER...SO
WILL MENTION A MIX FOR SUNDAY. FOR SUNDAY NIGHT IT WILL BE COLD
ENOUGH JUST FOR SNOW SHOWERS. SNOW SHOWERS WILL LINGER INTO MONDAY
NIGHT...LOW CHANCE WITH MOISTURE LIMITED EVEN THOUGH THE LAKE AND
850 MB TEMPERATURE DIFFERENCE WILL BE NEAR 20C.
ANOTHER FRONTAL SYSTEM WILL BE MOVING IN ON TUESDAY. SOME TIMING
QUESTIONS WITH THAT...SO WILL LEAVE THE POPS LOW FOR THE TIME BEING.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
HIGH PRESSURE MOVING OVER THE AREA THRU MIDNIGHT WILL HELP TO END
THE LAKE EFFECT SHSN AROUND ERI WHILE THE MVFR STRATO CU OVER ALL
BUT THE WESTERN AREA WILL RECEDE TO THE EAST. HIGH AND MID LEVEL
CLOUDS WILL SPREAD BACK IN FROM THE WEST LATER TONIGHT THRU MIDDAY
WED. SOME LIGHT SHSN MAY BE SPREADING ACROSS THE AREA AROUND AND
NEAR LERI BY LATE IN THE DAY WED BUT SINCE THE OVERALL POP FOR
ANYTHING MEASURABLE IS ONLY 30% WILL JUST CARRY 6SM SHSN OR VCSH IN
TAFS LATE WED AFTERNOON.
.OUTLOOK...NON VFR POSSIBLE WEDNESDAY NIGHT AND THURSDAY IN SNOW
SHOWERS.
&&
.MARINE...
SMALL CRAFT ADVISORIES WILL BE NEEDED FREQUENTLY INTO EARLY NEXT
WEEK...ESPECIALLY ON THE EAST END OF THE LAKE.
A RIDGE IS BUILDING IN TONIGHT...SO THE WINDS AND WAVES WILL
CONTINUE TO DECREASE. WILL LET THE SMALL CRAFT ADVISORY EXPIRE AT 9
PM ON THE EAST END...IT WILL BE CLOSE.
THE NEXT THREAT FOR A SMALL CRAFT ADVISORY WILL BE LATE WEDNESDAY
NIGHT INTO THURSDAY AFTER ANOTHER FRONT MOVES THROUGH. ANOTHER FRONT
MOVES THROUGH LATE FRIDAY AND SATURDAY NIGHT INTO SUNDAY. THIS FRONT
WILL PROMPT THE NEED FOR A SMALL CRAFT ADVISORY THAT MAY LAST INTO
EARLY NEXT WEEK AS THE WEST TO NORTHWEST FLOW WILL BE PERSISTENT.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...LAKE EFFECT SNOW ADVISORY UNTIL 10 PM EST THIS EVENING FOR
OHZ014-089.
PA...LAKE EFFECT SNOW ADVISORY UNTIL 10 PM EST THIS EVENING FOR
PAZ003.
LAKE EFFECT SNOW WARNING UNTIL 10 PM EST THIS EVENING FOR
PAZ001-002.
MARINE...SMALL CRAFT ADVISORY UNTIL 9 PM EST THIS EVENING FOR
LEZ146>149.
&&
$$
SYNOPSIS...LAPLANTE
NEAR TERM...LAPLANTE/MULLEN
SHORT TERM...LAPLANTE
LONG TERM...KIELTYKA
AVIATION...ADAMS
MARINE...KIELTYKA
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 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...
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
YOU CAN SEE AN ILLUSTRATED VERSION OF THE FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
841 PM CST TUE DEC 24 2013
.UPDATE...
FORECAST IS LOOKING PRETTY GOOD. NO SIGNIFICANT CHANGES NEEDED
YET...BUT WE/RE WATCHING THE CURRENT BACK EDGE TRENDS OVER IOWA.
THE HRRR JUST BRINGS THIS LEADING AREA OF WARM AIR ADVECTION
PRECIP THROUGH...LASTING JUST A FEW HOURS WITH VERY LITTLE BEHIND
IT. THE EARLIER MODELS WERE SUGGESTING MORE REDEVELOPMENT IN THE
PERSISTENT WAA FLOW COUPLED WITH THE DECENT SHORT WAVE. FOR A
WHILE I THOUGHT THE HRRR WAS GOING TO BE RIGHT...BUT OVER THE LAST
HOUR WE ARE SEEING REDEVELOPMENT ACROSS IOWA CAUSING THE PRECIP TO
FILL IN AND BECOME ONE LARGER AREA. IT STILL LOOKS LIKE THE
SOUTHERN CWA WILL SEE THE LEAST AMOUNT OF SNOW...MAYBE JUST AN
INCH OR LESS...WHILE THE NORTH SHOULD BE IN THE 3 INCH RANGE.
MADISON TO MILWAUKEE WOULD BE IN THAT 2 INCH RANGE.
&&
.AVIATION/06Z TAFS/...
EXPECT MVFR/IFR CIGS/VSBYS DUE TO THE SNOW ROLLING THROUGH THE
AREA OVERNIGHT. WE ARE EXPECTING THE SNOW TO TAPER OFF IN THE
MADISON AREA AROUND 3 AM...AND IN MILWAUKEE BETWEEN 5 AND 6 AM
WEDNESDAY MORNING. STILL LOOKING AT AROUND 2 INCHES AT
MILWAUKEE/MADISON/WAUKESHA AND PROBABLY AROUND AN INCH AT KENOSHA.
EXPECT MVFR CIGS TO HANG IN AFTER THE SNOW ENDS WITH ANOTHER ROUND
OF LIGHT SNOW EXPECTED WEDNESDAY AFTERNOON ASSOCIATED WITH A WEAK
MID LEVEL WAVE MOVING THROUGH. ANOTHER INCH OF SNOW ACCUM IS
POSSIBLE WITH THIS SECOND ROUND.
&&
.PREV DISCUSSION... /ISSUED 335 PM CST TUE DEC 24 2013/
TONIGHT AND WEDNESDAY - CONFIDENCE...HIGH.
IT SHOULD REMAIN DRY INTO EARLY THIS EVENING. SNOW WILL MOVE IN
QUICKLY THOUGH MID TO LATE EVENING...AS A STRONG SHORTWAVE
APPROACHES. STILL SEEING PRETTY GOOD SATURATION...WITH A FAIRLY DEEP
DENDRITE GROWTH ZONE...PARTICULARLY TOWARD THE NORTHEAST. MODELS
ALSO SHOWING DECENT LIFT WITH FAIRLY DEEP Q-VECTOR CONVERGENCE. HAVE
GENERALLY MAINTAINED THE FORECAST AS IS...WITH HIGH POPS AND 2 TO 3
INCHES OF SNOW EXPECTED BY DAYBREAK CHRISTMAS MORNING.
THERE WILL BE A BREAK IN THE SNOW FOR MOST OF THE MORNING
TOMORROW...WITH ANOTHER SHORTWAVE BRINGING SOME LIGHT SNOW TO THE
FORECAST AREA IN THE AFTERNOON. COULD SEE UPWARDS OF AN INCH BY
EARLY EVENING IN SOME SPOTS. IT WILL BE MILDER TOMORROW...THOUGH
HIGHS WILL STILL BE A FEW DEGREES BELOW NORMAL.
WEDNESDAY NIGHT THROUGH FRIDAY...FORECAST CONFIDENCE...MEDIUM.
LINGERING LAYER Q-VECTOR CONVERGENCE AND SLIGHTLY SLOWER MID-LEVEL
SHORT WAVE TROUGH EXIT SOUTHEAST WISCONSIN EARLY WEDNESDAY EVENING.
MORE CONSISTENT GFS IS SHOWING MORE PRONOUNCED AND SLOWER MOVING MID-
LEVEL TROUGH WHILE LATEST NAM MORE PROGRESSIVE WITH FORCING.
THINKING -SN WILL BE ONGOING IN THE EARLY EVENING IN THE SOUTHEAST
BEFORE ENDING WITH LIGHT ADDITIONAL ACCUMULATIONS.
WEAKENING UPSTREAM WARM AIR ADVECTION MAY CARRY SOME FLURRIES BACK
INTO SOUTHERN WI LATER WED NGT INTO THU. ANOTHER STRONGER SURGE OF
ISENTROPIC UPGLIDE AND LOWERING CONDENSATION PRESSURE DEFICITS MOVES
ACROSS SOUTHERN WI THU AFTN AND EVE. HOWEVER LOW TO MID-LEVEL RH
APPEARS SPARSE. ENOUGH MOISTURE EXPECTED TO BE IN PLACE AT THIS
POINT TO EXPAND SMALL CHANCE FOR LIGHT SNOW ACROSS THE NORTH DURING
THIS PERIOD WITH SCATTERED FLURRIES ELSEWHERE.
WARMER AIR BEGINS TO RETURN ON FRIDAY WITH DAYTIME TEMPS RETURNING
TO THE MID 20S.
FRIDAY NIGHT THROUGH TUESDAY...FORECAST CONFIDENCE...MEDIUM.
DECREASING TO LOW IN LATER PERIODS.
EXTENDED GUIDANCE IN REASONABLE AGREEMENT ON SOME RELAXATION OF COLD
NORTHWEST FLOW EARLY IN THE PERIOD...RESULTING IN SOME NOTICEABLE
DAYTIME WARMING...MOST NOTICEABLE ON SATURDAY. DAYTIME TEMPS WILL
BE WARMER ON FRIDAY BUT BRISK SOUTHWEST WINDS WILL ADD A NOTICEABLE
CHILL TO THE AIR. 85H TEMPS WARM TO 6-8C ON SATURDAY. PERSISTENT
SPRAWLING HIGH PRESSURE OVER THE SOUTH CENTRAL AND SOUTHEAST CONUS
SHOULD PREVENT SIGNIFICANT MOISTURE RETURN AHEAD OF APPROACHING COLD
FRONT. THINKING GFS MAY BE OVERDOING AMOUNT OF LOW LEVEL RH ON
SATURDAY SO AT LEAST PARTIAL SUNSHINE AND SOUTHWEST BREEZES MAY
ALLOW DAYTIME TEMPS TO NEAR FREEZING.
COLD FRONT AND WEAKENING SHEARED MID-LEVEL SHORT WAVE MAY HAVE JUST
ENOUGH MOISTURE AND OMEGA TO TRIGGER A LIGHT MIXED BAG OF PRECIP
SATURDAY NIGHT. FORECAST SOUNDINGS CONTINUE TO SHOW A SMALL CHANCE
FOR -ZR/-ZL CHANGING OVER TO -SHSN OR FLURRIES LATER SAT NIGHT INTO
SUN AS THE COLD AIR RETURNS. REINFORCING PUSH OF COLD AIR ON SUNDAY
MAY CONTRIBUTE TO MORE WIDESPREAD -SN OR -SHSN.
EARLY NEXT WEEK...85H TEMPS PLUMMET TO LEVELS EVEN LOWER THAN
CURRENT READINGS...FALLING TO 15 TO 20C BELOW BY 12Z/30. WIND
CHILLS MAY BECOME AN ISSUE SUNDAY NIGHT AND MONDAY NIGHT. BRISK
NORTHWEST FLOW TO PERSIST INTO THE NEW YEAR...HOWEVER GFS AND ECMWF
SHOWING INCREASING DISPARITY ON AMOUNT OF MID-LEVEL RIDGING OVER THE
NORTHERN PLAINS. ECMWF TRENDING MORE TOWARD POTENTIAL FOR WEAK
CLIPPER TYPE SYSTEM POTENTIALLY AFFECTING SRN WI AROUND MON NIGHT.
CONSIDERING BRISK NORTHWEST FLOW REGIME...AND WEAKER NEARBY
RIDGING...LEANING TOWARD WEAK SNOW PRODUCERS RETURNING AT THIS
TIME...AND WL CARRY SOME SMALL POPS IN THE LATE PERIODS.
AVIATION/00Z TAFS/...
VFR CONDITIONS WILL CONTINUE INTO EARLY THIS
EVENING. A STRONG SHORTWAVE WILL THEN BRING SNOW ACROSS THE AREA
LATE EVENING AND INTO THE NIGHT. LOOKS LIKE SNOW TOTALS WILL BE IN
THE 2 TO 3 INCH RANGE. THIS SNOW WILL LOWER CIGS AND VSBYS. WILL
HAVE TO KEEP AN EYE ON UPSTREAM OBS AND FINE TUNE THE TAFS AS THE
SNOW APPROACHES.
VSBYS SHOULD GO BACK TO VFR FOR A TIME TOMORROW MORNING AS THE SNOW
COMES TO AND END...WITH LOWER CLOUDS LIKELY LINGERING. ANOTHER
SHORTWAVE WILL BRING SOME LIGHT SNOW LATER IN THE DAY...WITH
VISIBILITIES LIKELY GOING BACK DOWN BELOW 6 MILES BY LATE AFTERNOON.
COULD SEE UP TO ANOTHER INCH OF SNOW BY EVENING IN SOME LOCATIONS.
MARINE...
BRISK SOUTH WINDS WILL DEVELOP LATER THIS AFTERNOON AND TONIGHT AS A
TIGHTENING SURFACE PRESSURE GRADIENT DEVELOPS BETWEEN DEPARTING HIGH
PRESSURE AND AN APPROACHING TROUGH OF LOW PRESSURE. WINDS WILL BACK
SOUTHWEST THEN WEST AS THE SURFACE TROUGH PASSES THROUGH WEDNESDAY.
THE BRISK WINDS WILL BUILD HIGH WAVES THAT WILL SUBSIDE WEDNESDAY
AFTERNOON WITH THE OFFSHORE FETCH.
DID NOT CHANGE THE SMALL CRAFT ADVISORY TIMING...THOUGH IT MAY
EVENTUALLY NEED TO BE EXTENDED INTO WEDNESDAY NIGHT DUE TO LINGERING
BREEZY WEST WINDS.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 6 PM CST WEDNESDAY FOR LMZ645-646.
SMALL CRAFT ADVISORY UNTIL 6 PM CST WEDNESDAY FOR LMZ643-644.
&&
$$
UPDATE...DAVIS
TONIGHT/WEDNESDAY AND AVIATION/MARINE...DDV
WEDNESDAY NIGHT THROUGH TUESDAY...MBK
AREA FORECAST DISCUSSION
NWS JACKSONVILLE FL
415 AM EST WED DEC 25 2013
.SHORT TERM...TODAY AND TONIGHT...STRONG SURFACE HIGH TO THE NORTH
WILL MOVE EAST REACHING THE EAST COAST BY THIS EVENING. CURRENT
IR SATELLITE IMAGERY SHOWS A LARGE AREA OF LOW CLOUDS OVER THE
OFFSHORE ATLANTIC WATERS. THESE LOW CLOUDS WILL ADVECT INTO THE
AREA TODAY AND TONIGHT WITH AN INVERTED TROUGH DEVELOPING OVER
THE COASTAL WATERS BY TONIGHT. ISOLATED SHOWERS POSSIBLE OVER THE
WATERS THIS MORNING REACHING THE COASTAL AREAS BY AS EARLY AS THIS
AFTERNOON. SREF...NAM12...AND RAP MODELS ARE THE MOST AGGRESSIVE
AND LOOK TOO FAST WITH THE SHOWERS. HAVE USED A BLEND WITH THE
SLOWER GFS. TEMPERATURES WILL BE COOL AGAIN TODAY DUE TO INCREASING
CLOUDINESS AND ONSHORE WINDS. LOWS TONIGHT WILL NOT BE AS COLD AS
THIS MORNING FOR THE SAME REASONS.
THU...HIGH PRES REMAINS N OF THE AREA AND LOW LEVEL NELY WINDS WILL
CONTINUE TO HELP INFLUX OF LOW LEVEL MOISTURE. LLVL MOISTURE
CONVERGENCE COMBINED WITH WEAK UPPER LEVEL DISTURBANCES WILL ALLOW FOR
A SLIGHT TO CHANCE OF SHOWERS FOR THE AREA BUT FORCING DOES LOOK
FAIRLY WEAK. WILL TWEAK INHERITED POPS DOWN A BIT TO 20-30%.
CONTINUED TO LEAN TOWARD COOLER SIDE OF GUIDANCE MAX TEMPS DUE TO
MOSTLY CLOUDY SKIES AND N-NELY WINDS.
THU NIGHT...MODELS CONTINUE TO PREDICT A SWATH OF MOISTURE ACROSS
THE AREA MAINLY ERN GULF...NE FL AND INTO THE WRN ATLC AS MID AND
UPPER LEVEL FLOW BACKS IN RESPONSE TO AN APPROACHING UPPER TROUGH.
SLIGHTLY BETTER FORCING ALOFT AND INCREASED MOISTURE SUGGESTS
SLIGHTLY HIGHER POPS ACROSS S ZONES BUT WILL KEEP MID CHANCE POPS
GOING...WITH ONLY 10-20% N PORTION. MIN RANGE FROM NEAR 40 N TO
LOWER TO MID 50S S PARTS.
FRI...INCREASED DIVERGENCE ALOFT AT 250 MB ATOP THE COOL N-NE
FLOW...PLENTY OF MOISTURE AVAILABLE (PWAT 1.3 INCHES) AND MID LEVEL
DISTURBANCES INDICATE INCREASED RAIN CHANCES...THOUGH BETTER CHANCES
MAY BE LATTER PART OF THE DAY. USED A BLEND OF AVAILABLE MOS
GUIDANCE DUE TO INCREASED UNCERTAINTY. BEST POPS PAINTED OVER NE FL
AT 50-60% AT THIS TIME. MAX TEMPS WILL BE HELD IN CHECK BY CLOUDS
AND PRECIP WITH UPPER 50S N TO MID 60S S. FRI NIGHT...SHORTWAVE
TROUGHING ACROSS THE LOWER MS VALLEY AND DEEPER SW FLOW ALOFT WILL
CONTINUE TO FEED MOISTURE FROM SW TO NE ACROSS THE FORECAST AREA.
BEING START OF DAY 4 CHOSE TO STAY CONSERVATIVE WITH POPS AND SO
CAPPED THEM AT 50% ACROSS NE FL AND 30-40% OVER SE GA BUT MOS
CURRENTLY SHOWS 60-70% IN SOME LOCATIONS. MINS FCST TO ONLY DECREASE
ABOUT 10 DEG FROM MAX TEMPS FROM FRI.
.LONG TERM...SAT-TUE.
A FAIRLY WET PATTERN SEEMS IN STORE INITIALLY WITH DEEP LAYER
MOISTURE (PWAT 1.5 INCHES) ACROSS NE FL AND SE GA SAT WITH A FAIRLY
STRONG SHORTWAVE TROUGH PROGRESSING ACROSS THE LOWER CONUS DURING
THE WEEKEND...PUSHING OFFSHORE THE E COAST BY LATE SUN NIGHT. FOR
NOW INDICATED RAIN CHANCES IN THE 40-60% RANGE SAT-SUN MORNING AND
TAPERED DOWN TO 20-30% BY SUN AFTN. UNCERTAINTY IS MEDIUM WITH
TIMING OF THE SLOWLY WEAKENING SHORTWAVE AS IT TRANSLATES EWD...WITH
THE GFS A GOOD 12 HRS FASTER. LEFT THUNDER OUT OF FCST FOR NOW WITH
VERY WEAK INSTABILITY. IT DOES LOOK LIKE SOME HEAVIER PRECIP
POTENTIAL IS POSSIBLE DUE TO THE STRENGTH OF THE SHORTWAVE WAVE BUT
TOO EARLY FOR SPECIFICS. BASED ON ECMWF AND GFS MOST PRECIP APPEARS
TO MOVE OUT OF THE AREA BY LATE SUN NIGHT WITH A COOLER AND DRIER
AIRMASS MOVING MON AND TUE. A REINFORCED SHOT OF COOL AIR MOVES IN
MON NIGHT AS WELL AND SFC HIGH MOVES THRU GA AND SC ON TUE.
&&
.AVIATION...CURRENTLY VFR CONDITIONS WITH CLEAR SKIES AND NORTH
WINDS AROUND 5 KNOTS. EXPECT STRATOCUMULUS TO ADVECT INLAND
AFFECTING MAINLY SSI AND CRG AROUND 12Z WITH MVFR CIGS. EXPECT
MVFR CIGS TO REACH JAX AND VQQ BY 15Z AND THEN GNV AROUND MIDDAY.
HAVE VCSH AT CRG AND SSI AFTER 22Z WITH THE POSSIBILITY OF IFR
CIGS TONIGHT.
&&
.MARINE...INVERTED COASTAL TROUGH PROGGED BY MODELS TO DEVELOP
OVER THE WATERS BY THIS EVENING. WILL CONTINUE WITH MARGINAL
ADVISORY OVER THE OFFSHORE WATERS TODAY AND CAUTION NEAR SHORE.
INVERTED TROUGH WILL LIKELY CAUSE A DECREASE IN WIND SPEEDS TONIGHT
AND EARLY THURSDAY BELOW ADVISORY LEVELS WITH SEAS REMAINING
ELEVATED. UNFAVORABLE BOATING CONDS LOOK TO EXIST MUCH OF THE PERIOD
WITH N TO NE WINDS GENERALLY IN THE 12 TO 20 KT RANGE AND SEAS
AROUND 3-5 FT NEARSHORE AND 4-7 FT OFFSHORE. SMALL CRAFT ADVY CONDS
LOOK POSSIBLE THU NIGHT INTO SAT AS COASTAL TROUGH REMAINS BEHIND 60
NM AND SFC HIGH PRES PUSHES SEWD TOWARD THE SE COAST PINCHING THE
LOCAL PRES GRADIENT. A QUICK INCREASE IN N-NW FLOW IS POSSIBLE SUN
AS WELL WITH SFC LOW PRES DEVELOPING NEAR OR E OF THE GULF STREAM AS
AN UPPER DISTURBANCE MOVES THROUGH THE AREA...BUT NOT ENOUGH
CONFIDENCE TO GO HIGH ON THE WINDS AT THIS POINT.
RIP CURRENTS: MODERATE RISK WILL CONTINUE THROUGH THE WEEK DUE TO
ELEVATED ONSHORE WINDS AND SEAS.
&&
.PRELIMINARY POINT TEMPS/POPS...
AMG 55 41 54 38 / 0 20 20 10
SSI 58 48 56 45 / 20 30 30 30
JAX 59 45 57 45 / 10 30 30 40
SGJ 61 53 61 52 / 10 30 40 50
GNV 64 48 61 46 / 0 20 40 50
OCF 66 49 63 50 / 0 20 40 50
&&
.JAX WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GA...NONE.
AM...SMALL CRAFT ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR ALTAMAHA
SOUND GA TO FERNANDINA BEACH FL 20 NM TO 60 NM OFFSHORE-
FERNANDINA BEACH TO ST AUGUSTINE FL 20 NM TO 60 NM OFFSHORE-
ST AUGUSTINE TO FLAGLER BEACH FL 20 NM TO 60 NM OFFSHORE.
&&
$$
ZIBURA/SHASHY/
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
312 AM EST WED DEC 25 2013
...CHILLY CHRISTMAS MORNING FOR WEST CENTRAL AND SOUTHWEST
FLORIDA...
.SHORT TERM /TODAY-FRIDAY/...
CHRISTMAS MORNING BEGINS WITH A CHILL IN THE AIR...AS MUCH OF WEST
CENTRAL AND SOUTHWEST FLORIDA IS IN THE 40S AND 50S. PORTIONS OF
LEVY COUNTY ARE IN THE UPPER 30S TO LOWER 40S...STARTING TO
BELIEVE THAT SOME HIGH CLOUDS COULD PREVENT THE EFFICIENT
RADIATIONAL COOLING PREVIOUSLY EXPECTED. THE FREEZE WARNING FOR
LEVY REMAINS POSTED...AND WILL BE EXAMINED AGAIN IN THE COMING
HOURS AS WE NEAR SUNRISE.
THE STALLED FRONT THAT PASSED THROUGH THE AREA YESTERDAY WILL
BEGIN TO SEEP NORTHWARD...PROVIDING A RETURN OF MOISTURE ALL THE
WAY INTO NORTH FLORIDA BY THE END OF CHRISTMAS DAY. PORTIONS OF
NORTH FLORIDA COULD SEE INCREASING CLOUD COVERAGE...AS ADVERTISED
IN SOME GUIDANCE INCLUDING THE SREF...WHICH COULD KEEP
TEMPERATURES ACROSS THE NATURE COAST IN THE 60S OR LOWER 70S.
OTHERWISE...THE AREA TO THE SOUTH OF THAT CLOUD COVER SHOULD BE
ABLE TO REACH INTO THE 70S BEFORE CLOUDS ASSOCIATED WITH THE
RETURN FRONTAL MOISTURE MOVE IN THIS AFTERNOON.
ONE BENEFIT TO THE CLOUD COVER WILL BE THAT TEMPERATURES ON
CHRISTMAS NIGHT WILL BE A TAD WARMER. AREAS OF THE NATURE COAST
WILL BE IN THE UPPER 40S TO LOWER 50S...WITH AREAS AROUND TAMPA
BAY IN THE MID 50S TO LOWER 60S IN SW FLORIDA. THE ADDITIONAL
MOISTURE WILL ALSO CREATE INCREASING RAIN SHOWER CHANCES...WHICH
TREND INTO A WETTER END TO THE WEEK. MODEL GUIDANCE IS MIXED AS TO
RAIN TIMING...WITH THE 00Z NAM MET MOS KICKING IN THE RAIN CHANCES
MUCH SOONER THAN THE 00Z GFS MAV MOS GUIDANCE. TOOK A MIDDLE OF
THE ROAD APPROACH TO MUCH OF THE FORECAST...TRENDING WET INTO THE
WEEKEND SIMILAR TO PREVIOUS FORECASTS. A MID-LEVEL TROUGH
SWINGING THROUGH THE EASTERN UNITED STATES ON THURSDAY SHOULD
PROVIDE SUPPORT FOR RAIN SHOWERS THURSDAY EVENING THROUGH
THURSDAY NIGHT. COMBINE THAT WITH THE RETREATING FRONT COMING IN
FROM THE SOUTH AND RAIN SHOWER CHANCES SHOULD BE MORE SOLID THAN
THEY WERE WITH THIS LAST FRONT.
THE CLOUDY AND WET PATTERN WILL BE REINFORCED ON FRIDAY THANKS TO
A HEALTHY STREAM OF GULF MOISTURE ALONG WITH THE REMNANT FRONTAL
BOUNDARY. TEMPERATURES COULD BE A BIT TRICKY DEPENDING ON HOW MUCH
CLOUD COVER IS OVER A LOCATION. THE LOCATION OF THE BOUNDARY WILL
PLAY A LARGER ROLE ON FRIDAY...WITH GUIDANCE BRINGING A CONSENSUS
WITH THE PEAK CLOUD COVER SITTING NORTH OF TAMPA BAY. IF THIS
CHANGES...SO DRASTICALLY COULD TEMPERATURES FOR FRIDAY.
WE WISH YOU A MERRY CHRISTMAS AND HOPE THAT YOU ENJOY THE DAY!
.LONG TERM /FRI NIGHT-WEDNESDAY/...
AN U/L RIDGE OVER THE FOUR CORNERS AREA WILL WEAKEN SATURDAY
WHILE A STRONG U/L DISTURBANCE PUSHES SOUTH DOWN THE CALIFORNIA
COAST. ANOTHER U/L DISTURBANCE WILL BE OVER THE LOWER MISSISSIPPI
VALLEY AND WILL MOVE EAST ALONG THE NORTHERN GULF OF MEXICO.
PREVIOUS RUNS HAD THE DISTURBANCE ALONG THE CALIFORNIA COAST
CUTTING OFF AND FORMING A REX BLOCK OFF THE CALIFORNIA COAST.
CURRENT GUIDANCE NOW TRENDING TOWARD DISTURBANCE REMAINING IN
SOUTHERN STREAM FLOW AND DIGGING OVER THE SOUTHWEST U.S. AND BAJA
CALIFORNIA SUNDAY...WITH THE LEAD SOUTHERN STREAM DISTURBANCE OVER
THE LOWER MISSISSIPPI VALLEY MOVING EAST ACROSS THE SOUTHEAST U.S.
AND FLORIDA SATURDAY NIGHT AND SUNDAY. L/W TROUGH ASSOCIATED WITH
MAIN NORTHERN STREAM FLOW WILL BE LOCATED FROM HUDSON BAY SOUTH
THROUGH THE OHIO RIVER VALLEY SUNDAY NIGHT AND MONDAY...WITH QUASI
ZONAL FLOW ACROSS THE GULF OF MEXICO AND FLORIDA IN THE SOUTHERN
STREAM. NORTHERN STREAM TROUGH WILL ROTATE EAST OFF THE EASTERN
SEABOARD MONDAY NIGHT AND TUESDAY WITH ADDITIONAL WEAKER IMPULSES
DROPPING DOWN THE BACKSIDE OF THE TROUGH...WITH THE DISTURBANCE
OVER THE SOUTHWEST U.S. SLOWLY MOVING ACROSS TEXAS...WEAKENING AND
OPENING UP WHILE BEING ABSORBED IN THE NORTHERN STREAM FLOW.
AT THE SURFACE...STATIONARY FRONTAL BOUNDARY WILL BE LOCATED ACROSS
THE CENTRAL FLORIDA PENINSULA FRIDAY NIGHT THROUGH EARLY SUNDAY. AN
INCREASING CHANCE OF SHOWERS ACROSS THE FORECAST AREA FRIDAY NIGHT
AND SATURDAY WHICH WILL BE ENHANCED BY THE APPROACHING U/L
DISTURBANCE. WILL TREND POPS BELOW GUIDANCE AT THIS POINT AS
GUIDANCE HAS BEEN INCONSISTENT WITH AREAL COVERAGE OF RAIN. WEAK
SURFACE LOW MAY DEVELOP ALONG THE FRONTAL BOUNDARY WHICH WOULD
ENHANCE LOW LEVEL CONVERGENCE. AS THE U/L DISTURBANCE MOVES EAST OF
THE AREA ON SUNDAY...IT WILL PUSH THE FRONTAL BOUNDARY SOUTH OF THE
FLORIDA PENINSULA. SURFACE HIGH PRESSURE WILL BUILD OVER WEST
CENTRAL AND SOUTHWEST FLORIDA SUNDAY AND MONDAY IN THE WAKE OF THE
DISTURBANCE WITH SLIGHTLY COOLER DRIER AIR ADVECTING OVER THE AREA.
A WEAK SECONDARY COLD FRONT WILL PUSH ACROSS THE FLORIDA PENINSULA
MONDAY NIGHT REINFORCING THE COOLER DRIER AIRMASS. TEMPERATURES
WILL BEGIN ABOVE CLIMATIC NORMALS SATURDAY AND SUNDAY BUT WILL COOL
TO NEAR CLIMATIC NORMALS MONDAY THROUGH WEDNESDAY.
&&
.AVIATION...
VFR CONDITIONS EXPECTED FOR THE NEXT 24 HOURS. VFR CIGS 040-050
SPREADING OVER SOUTHWEST FLORIDA VCNTY RSW/FMY/PGD EARLY THIS
MORNING...AND GRADUALLY LIFTING NORTHWEST TOWARD THE REMAINING
TERMINALS BY THIS AFTERNOON.
&&
.MARINE...
HAVE EXTENDED THE SMALL CRAFT ADVISORY FOR THE SOUTHERN OUTER
WATERS A FEW HOURS...AND HAVE ALLOWED THE OTHERS TO EXPIRE. ISSUED
SCEC FOR TAMPA BAY THANKS TO GUSTY WINDS REPORTED IN AND AROUND
THE BAY...MAINLY IN PINELLAS COUNTY THIS MORNING. WILL CONTINUE TO
MONITOR AND UPDATE PRODUCTS AS NECESSARY.
&&
.FIRE WEATHER...
MOISTURE RETURN TODAY SHOULD MITIGATE ANY FIRE WEATHER CONCERNS
THROUGH THE END OF THE WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 73 59 75 59 / 0 30 30 40
FMY 78 62 82 63 / 10 20 30 30
GIF 73 56 76 57 / 10 20 30 30
SRQ 75 59 77 61 / 0 30 30 40
BKV 72 53 74 58 / 0 10 30 40
SPG 71 60 73 62 / 0 30 30 40
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...FREEZE WARNING UNTIL 8 AM EST THIS MORNING FOR COASTAL
LEVY-INLAND LEVY.
GULF WATERS...SMALL CRAFT ADVISORY UNTIL 7 AM EST THIS MORNING FOR
BONITA BEACH TO ENGLEWOOD OUT 20 TO 60 NM-ENGLEWOOD
TO TARPON SPRINGS OUT 20 TO 60 NM.
&&
$$
SHORT TERM/MARINE/FIRE WEATHER...02/GARCIA
LONG TERM/AVIATION...13/OGLESBY
[top]
Area Forecast Discussion
National Weather Service Tallahassee FL
246 AM EST Wed Dec 25 2013
.Near Term [Today]...
The Christmas Day temperature forecast in our area is a bit tricky,
complicated by the arrival of a couple different cloud layers. The
first cloud layer is a low stratus deck that has evolved in the last
6-10 hours just offshore coastal SC, GA, and NE FL. Model guidance
is in good agreement to gradually veer the flow in the 925-850mb
layer to an E-ESE direction by the mid-morning hours, which should
cause the stratus deck and greater low-level moisture to spread
inland from the Atlantic, underneath a pronounced inversion. The
second cloud layer will be a band of increasing cirrostratus that
should gradually lower to around 15-20kft during the day per model
forecast soundings. The consensus is that 500-300mb RH will quickly
spike to around 80% between 18-21z, which should create a veil of
high cloud cover over the area this afternoon. The question, of
course, is whether or not the cloud cover arrives in sufficient time
to significantly limit daytime heating. Confidence would be highest
in this occurring (with the stratus deck advancing from the east)
over SC GA, particularly east of a TVI-ABY line.
The latest runs of the RAP hold temperatures in the mid-upper 40s
all day in our Georgia zones consistent with the idea of an
expanding stratus deck. We did not lower the high temperature
forecast quite that aggressively, but more raw model guidance was
blended in with the usually favored MOS over land to produce highs
mostly in the lower 50s in the northern half of the area. It should
be noted that there is a considerable range of possibilities for
"Day 1" of the forecast. An early arrival of the stratus layer could
realistically produce highs in the 40s in SW GA. Cloud cover that
takes longer to materialize could yield mid-upper 50s in those same
areas. For now we`ve taken a compromise approach and our forecast
generally lies near or just below the model average.
.Short Term [Tonight Through Friday]...
Our forecast area will come under the influence of moistening
southwest flow aloft as the polar jet stream remains well north of
our region. A series of short wave troughs will translate quickly
eastward across the northern CONUS, leaving our area to get "fringe"
effects from these systems as they pass quickly to our north.
Additionally there will be a slow-moving, positively tilted trough
over the western Gulf of Mexico. The result of this pattern is a
rather tricky forecast, as forecasting the timing and interaction of
these systems is often difficult.
The first system will affect our region tonight. Although there will
be an increase in moisture and Q-G forcing, there will likely be
some residual dry layers (as indicated in the forecast soundings),
so our QPF and PoP is low. Moisture and Q-G forcing will gradually
increase again Thursday night and Friday, with a corresponding
increase in PoP. Rain chances will generally be confined to the
region along and south of a line from Valdosta to Cape San Blas, as
north of this line it will probably be too dry for rain. Even where
rain is possible, we expect it to be too stable and the forcing too
weak for thunderstorms. Lows will range from the mid to upper 30s in
our northwest zones to mid 40s in our FL zones. Highs will be in the
upper 50s to lower 60s, unless there are more clouds and rain than
currently forecast.
.Long Term [Friday Night Through Wednesday]...
Some fairly significant changes to the new long term fcst as the
latest run of the ECMWF shows a more potent upper level shortwave
digging down into TX early in the weekend. It now appears that this
system will have just enough punch to potentially give us another
wet weekend with increasing rain chances for Sat. and Sun. Even the
GFS is starting to trend in this direction, so confidence for higher
PoPs is increasing for the beginning of the extended fcst.
Thereafter, however, it appears that the upper level pattern will
become very progressive, with a couple of fast moving shortwave trofs
moving through the region during the early to middle portion of next
week. This should keep conditions on the fair, cool, and dry side
for the remainder of the period, as we usher in the New Year of
2014 on next Wed.
&&
.Aviation...
[Through 06Z Thursday] Model guidance is in very good agreement
that a stratus deck will expand inland over SE GA and NE FL early
this morning, and eventually into parts of the FL Big Bend and SW
GA by midday or early afternoon. This would be most likely to
impact VLD and ABY, with TLH and DHN peripherally affected.
Several short term ensembles have the probability of MVFR CIGS at
ABY and VLD climbing to around 90% by 18z, with lesser values of
50-60% at TLH and DHN. Model forecast soundings show the ceiling
could be as low as 2000 feet. For now, we included a 3000ft -
marginal MVFR - ceiling at the aforementioned TAF sites, gradually
spreading ESE-WNW today.
&&
.Marine...
Winds and seas were below advisory levels this early morning.
However, moderate northeast winds are likely to continue for the
next several days as a series of high pressure systems develop to
our north.
&&
.Fire Weather...
Humidity will moderate from the low levels yesterday for the rest of
the week. Red flag conditions are not expected.
&&
.Hydrology...
Increased flows from rainfall over the weekend continue to progress
through the river system. There is still a possibility that the
Choctawhatchee River at Caryville could reach minor flood stage on
12/27, however measured flows within the Pea and upper Choctawhatchee
Rivers may not be sufficient enough for the lower Choctawhatchee
to flood.
Releases from Woodruff Dam continue and have been increased to
45 kcs this evening and may move to near 50 kcfs on Wednesday. As a
result, Blountstown will reach flood stage on 12/25 and should
remain in the minor flood category for some time.
Elsewhere in the region, the Shoal River in Walton County has
crested and will continue to sharply fall. Modest rises on the
Flint will continue, but should stay at or just below action
levels through the weekend. East of the Flint River drainage area,
rainfall was insufficient to result in any significant rises in
the Withlacoochee or Suwannee River systems.
&&
.Preliminary Point Temps/PoPs...
Tallahassee 57 45 60 42 61 / 0 20 20 20 20
Panama City 60 45 60 46 62 / 0 10 10 10 10
Dothan 52 38 57 38 61 / 0 10 10 10 0
Albany 51 38 57 37 59 / 0 20 20 10 10
Valdosta 55 43 58 41 60 / 0 20 20 20 20
Cross City 66 47 66 47 62 / 0 10 20 40 40
Apalachicola 60 47 61 49 62 / 0 20 20 20 20
&&
.TAE Watches/Warnings/Advisories...
FL...Freeze Warning until 9 AM EST /8 AM CST/ this morning for
Calhoun-Central Walton-Coastal Bay-Coastal Dixie-Coastal
Franklin-Coastal Gulf-Coastal Jefferson-Coastal Taylor-
Coastal Wakulla-Gadsden-Holmes-Inland Bay-Inland Dixie-
Inland Franklin-Inland Gulf-Inland Jefferson-Inland Taylor-
Inland Wakulla-Inland Walton-Jackson-Lafayette-Leon-Liberty-
Madison-South Walton-Washington.
GA...Freeze Warning until 9 AM EST this morning for Baker-Ben Hill-
Berrien-Brooks-Calhoun-Clay-Colquitt-Cook-Decatur-Dougherty-
Early-Grady-Irwin-Lanier-Lee-Lowndes-Miller-Mitchell-
Quitman-Randolph-Seminole-Terrell-Thomas-Tift-Turner-Worth.
AL...Freeze Warning until 8 AM CST this morning for Coffee-Dale-
Geneva-Henry-Houston.
GM...None.
&&
$$
Near Term...Lamers
Short Term...Fournier
Long Term...Gould
Aviation...Lamers
Marine...Fournier
Fire Weather...Lamers
Hydrology...Godsey
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1201 AM CST WED DEC 25 2013
.DISCUSSION...
810 PM CST
MADE SOME ADJUSTMENTS TO HOURLY TEMPERATURES TO ACCOUNT FOR A
QUICK FALL THIS EVENING...BUT WITH CLOUD COVER THICKENING AND
LOWERING AND WARM AIR ADVECTION STRENGTHENING WOULD ANTICIPATE
STEADY OR RISING TEMPS THE REMAINDER OF THE NIGHT.
FIRST BATCH OF SNOW OVER EASTERN IOWA LOOKS TO BE TAKING AIM ON
MOSTLY WISCONSIN AS VERY DRY AIR (RH AROUND 10% AT 850MB ON 00Z
DVN SOUNDING) IS RESULTING IN A BIG VIRGA STORM OVER NORTHERN
ILLINOIS AT THIS TIME. GUIDANCE STILL INDICATES THAT INCREASING
ASCENT AND CONTINUED MOISTENING FROM TOP DOWN WILL LIKELY RESULT
IN SATURATION AND SNOW DEVELOPING LATER THIS EVENING AND
PARTICULARLY AFTER MIDNIGHT. LATEST SUITE OF GUIDANCE HAS BEEN
INCREASINGLY PESSIMISTIC WITH RESPECT TO QPF AMOUNTS OVER OUR CWA
LATER TONIGHT INTO XMAS MORNING. WOULD NOT TAKE MUCH TO SQUEEZE
OUT A TENTH OF AN INCH OF SNOWFALL SO ONLY GOING TO SCALE BACK
POPS SLIGHTLY OVER CENTRAL AND SOUTHERN PORTIONS OF THE CWA WHILE
MAINTAINING CATEGORICAL. REGARDING SNOWFALL TOTALS...LATEST
GUIDANCE WOULD SUGGEST THAT EVEN AN INCH WOULD BE UNATTAINABLE
WITH THIS SYSTEM EXCEPT FOR FAR NORTHERN COUNTIES. NOT TERRIBLY
KEEN ON MAKING BIG CHANGES ON THIS SHIFT...SO GOING TO JUST GENTLY
SCALE BACK AMOUNTS A BIT RATHER THAN GO WITH WHAT IS LOOKING TO BE
THE MORE LIKELY SCENARIO WHICH IS MOST AREAS GETTING LITTLE MORE
THAN A DUSTING THROUGH CHRISTMAS MORNING.
SECOND SHORTWAVE PIVOTING AROUND THE POLAR VORTEX STILL LOOKS ON
TARGET TO BRING ANOTHER CHANCE OF SNOW SHOWERS LATER TOMORROW
AFTERNOON INTO TOMORROW EVENING...AGAIN ESPECIALLY NORTHERN CWA.
WILL LET THE NIGHT CREW HANDLE ANY GRID ADJUSTMENTS WITH THAT
SYSTEM.
IZZI
//PREV DISCUSSION...
225 PM CST
MAIN FORECAST CONCERNS WILL BE HONING IN ON A PAIR OF DISTURBANCES
BRINGING ACCUMULATING SNOW TONIGHT AND AGAIN DURING THE EVENING
TOMORROW...AS WELL AS TEMPERATURE TRENDS WITH NON-DIURNAL TEMPS
TONIGHT AND BITTER COLD RETURNING EARLY NEXT WEEK.
TODAY AND TONIGHT...
PAIR OF UPPER LEVEL DISTURBANCES EVIDENT ON WATER VAPOR IMAGERY THIS
AFTERNOON...THE FIRST TRANSLATING EAST ACROSS NEBRASKA...WHILE A
SECOND WAVE IS DIGGING ACROSS THE CANADIAN PRAIRIES. THE SOUTHERN
WAVE IS FORECAST TO LIFT ACROSS NRN IL/SRN WI OVERNIGHT. ISENTROPIC
ASCENT INCREASES AHEAD OF THE WAVE LATE THIS EVENING...WITH TOP DOWN
SATURATION GRADUALLY EATING AWAY AT THE VERY DRY AIR MASS CURRENTLY
IN PLACE. MOST MODELS INDICATE THAT PRECIP WILL BEGIN JUST BEFORE
MIDNIGHT OVER NORTH CENTRAL ILLINOIS AND INITIALLY WILL BE MAINLY
CONFINED TO THE TIER OR TWO OF COUNTIES NEAR THE STATE LINE WITH DRY
AIR WINNING OUT OVER AREAS FARTHER SOUTH. COLD TEMPERATURES WITH A
FAIRLY DEEP ISOTHERMAL LAYER THAT EXTEND FROM NEAR THE SURFACE TO
ABOUT 6KFT AND COINCIDES NEAR THE BASE OF THE DENDRITIC GROWTH ZONE
WILL HELP LEAD TO FLUFFIER THAN AVERAGE SNOW RATIOS...17-20:1
INITIALLY PER COBB OUTPUT. BETTER FORCING ASSOCIATED WITH THE UPPER
WAVE WILL BE RIGHT ON THE HEALS OF THIS FIRST WARM ADVECTION BURST
OF SNOW AND WILL LEAD TO SNOW SPREADING SOUTHEAST ACROSS THE
REMAINDER OF THE CWA...INCLUDING THE CHICAGO METRO AREA BY AROUND
3AM CST. DGZ NOT NEARLY AS DEEP OVER REMAINDER OF CWA WITH SLIGHTLY
WARMER TEMPS IN THE LOW/MID LEVELS AND A 2-3KFT DEEP DGZ NEAR THE
TOP OF THE SATURATED LAYER BUT COINCIDING WITH THE BETTER LIFT. THIS
WILL RESULT IN STILL DRY BUT CLOSER TO AVERAGE RATIOS OF 14-16:1.
WITH A BLEND OF NAM/GFS TIMING/QPF THIS EVENING...CONTINUE TO CALL
FOR 1-3 INCHES OF SNOW NORTH OF THE I-88 CORRIDOR...1 TO 2 INCHES
BETWEEN I-88 AND A PONTIAC TO VALPARAISO LINE...AND UP TO AN INCH
SOUTH OF THAT LINE.
IN ADDITION TO ACCUMULATING SNOWFALL...PRESSURE GRADIENT WILL
TIGHTEN BETWEEN A STRONG DEPARTING HIGH CURRENTLY OVERHEAD AND THE
APPROACHING FRONTAL TROUGH. THIS WILL RESULT IN BREEZY CONDITIONS
DEVELOPING OVERNIGHT WITH GUSTS INTO THE 20 TO 25 MPH RANGE. GIVEN
THE DRY NATURE OF THE SNOW...THIS WILL LIKELY CONTINUE TO BLOW SNOW
AROUND AFTER IT FALLS TO THE SURFACE. THE INCREASING SOUTHERLY FLOW
WILL ALSO LEAD TO WARMING TEMPERATURES THROUGH THE OVERNIGHT HOURS
WITH LOWS HAPPENING THIS EVENING. BY DAYBREAK TOMORROW...EXPECT
TEMPERATURES TO WARM INTO THE HIGH TEENS TO LOW 20S.
WEDNESDAY THROUGH FRIDAY...
AFOREMENTIONED NORTHERN WAVE WILL CONTINUE TO DIG INTO THE
MIDWEST...CARVING OUT A TROUGH THAT WILL SHIFT EAST ACROSS THE AREA
LATE WEDNESDAY EVENING. MOISTURE WITH THIS SECOND WAVE IS MORE
SHALLOW...AND WILL BE LOOKING AT CLOSER TO AVERAGE SNOW RATIOS.
QUICK HITTING SYSTEM MAY PRODUCE UP TO AN ADDITIONAL INCH NORTH OF
THE I-88 CORRIDOR WITH LITTLE IF ANY SNOW SOUTH. TEMPERATURES
WEDNESDAY NIGHT A BIT TRICKY...WITH SOME GUIDANCE POINTING AT MUCH
COOLER TEMPS THAN FORECAST...IN FACT SUB ZERO WEST OF THE FOX RIVER
VALLEY. HOWEVER...YET ANOTHER VORT LOBE WILL PIVOT ACROSS THE
AREA...AND WHILE DO NOT EXPECT ANY APPRECIABLE PRECIP WITH THIS
WAVE...IT SHOULD AT LEAST HOLD ONTO CLOUD COVER OVERNIGHT. WITH THE
RIDGE AXIS CENTERED OVER IOWA...DOES NOT APPEAR TO FAVOR A STRONG
RADIATIONAL COOLING SETUP AND WILL DISMISS THE COLDEST GUIDANCE.
RIDGE AXIS WILL ARRIVE OVERHEAD MIDDAY THURSDAY AND SHOULD KEEP
CONDITIONS DRY MOST OF THURSDAY AND FRIDAY. THOUGH AS THE SURFACE
RIDGE BREAKS DOWN LATER THURSDAY AND FRIDAY...WITH THE AREA UNDER
NORTHWEST FLOW WILL HAVE TO KEEP AN EYE ON THE POTENTIAL FOR A EVEN
A WEAK UPPER LEVEL DISTURBANCE TO SQUEEZE OUT SOME LIGHT SNOW...AS
SUGGESTED BY THE NAM. WILL KEEP "SILENT" 10-14 POPS IN THE MEANTIME.
SATURDAY THROUGH TUESDAY...
MODELS HAVE BEEN ADVERTISING A RELATIVELY STRONG CLIPPER SYSTEM TO
IMPACT PRIMARILY THE NORTHERN LAKES REGION OVER THE WEEKEND WITH
SMALL CHANCES FOR SNOW INTO NORTHERN ILLINOIS WITH A STRONG COLD
FRONT SWEEPING ACROSS THE AREA. AHEAD OF THE FRONT ON SATURDAY...
7-8C H85 THERMAL RIDGE WILL ADVECT OVERHEAD. EVEN WITH SOME SNOW ON
THE GROUND...LOCAL UPPER AIR CLIMATOLOGY SUGGESTS THAT MOST AREAS
SHOULD BE ABLE TO GET WELL INTO THE 30S...WITH LOW 40S EVEN A
POSSIBILITY...AN IDEA SUPPORTED BY A CONSENSUS MODEL BLEND. A STRONG
COLD FRONT WILL SWEEP ACROSS THE AREA SATURDAY NIGHT INTO SUNDAY
WITH H85 TEMPS PLUMMETING TO -17 TO -18C BY SUNDAY NIGHT. DEPENDING
ON THE EXACT TIMING THE OF THE FRONT...THIS COULD LEAD TO EARLY
MORNING LOWS SUNDAY WITH TEMPS FALLING THROUGH THE DAY AND
NIGHT...BOTTOMING OUT IN THE LOW SINGLE DIGITS OR EVEN BELOW ZERO
ONCE AGAIN...WITH THE COLD AIR MASS LINGERING INTO THE DAY TUESDAY.
BACK UNDER NORTHWEST FLOW ALOFT...THERE WILL BE PERIODIC CHANCES FOR
LIGHT SNOW EARLY NEXT WEEK.
DEUBELBEISS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* LIGHT SNOW POSSIBLY REDEVELOPS LATE TONIGHT ARND 9Z AND
CONTINUES THRU 12Z.
* VFR CIGS THEN DIMINISH TO LOW END MVFR WITH LGT SNOW
ARRIVAL...THEN BORDERLINE IFR CIGS ARND DAYBREAK THRU MIDDAY.
* MVFR TO VFR CIGS BY LATE WED AFTN.
* ANOTHER PERIOD OF LGT SNOW AFT 23Z THRU 03Z THUR.
BEACHLER
//DISCUSSION...UPDATED 06Z...
CLIPPER SYSTEM CONTINUES TO SLIDE EAST ACROSS THE REGION. REGIONAL
RADAR SHOWS A BREAK IN THE LIGHT SNOW ACROSS NORTHERN IL/NORTHWEST
IN...HOWEVER A SECOND WAVE APPEARS TO BE DEVELOPING AND MAY
REDEVELOP THE LIGHT SNOW ACROSS THE AREA ARND 9-10Z AND CONTINUE
THRU 12Z. CIGS HAVE HELD UP AT VFR CONDS...AND WITH LGT SNOW
REDEVELOPING CIGS SHUD COME DOWN TO LOW END MVFR CONDS. GUIDANCE
THEN CONTINUES TO SUGGEST CIGS WILL HOLD DOWN AT MVFR TO
BORDERLINE IFR CONDS THRU MIDDAY. AS WINDS REMAIN SOUTHERLY WITH
OCCASIONAL GUSTS TO 15-19KT...SOME DRY AIR EVENTUALLY WORKS BACK
INTO THE AREA MIDDAY AND ALLOWS CIGS TO LIFT TO HIGH END MVFR
CONDS. THEN YET ANOTHER CLIPPER IS POISED TO ARRIVE AFT 22Z...WITH
LIGHT SNOW DEVELOPING ARND 00-03Z THUR.
BEACHLER
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* MEDIUM CONFIDENCE ON REDEVELOPING LGT SNOW AFT 9Z THRU 12Z.
* HIGH CONFIDENCE IN CIGS THRU 12Z...MEDIUM CONFIDENCE IN CIGS AFT
12Z THRU MIDDAY.
* HIGH CONFIDENCE IN WIND DIR/SPEED/GUSTS.
* LOW/MEDIUM CONFIDENCE IN LGT SNOW DEVELOPING AFT 22Z.
BEACHLER
//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...
THU THROUGH MON...VFR. SLIGHT CHANCE -SN ON SUN AS WELL AS MON
NIGHT.
&&
.MARINE...
215 PM CST
MAIN CONCERNS FOR THE LAKE ARE GALES DEVELOPING THIS EVENING AND
CONTINUE THROUGH WEDNESDAY MORNING.
HAZARDOUS WAVES/WINDS WILL ALSO DEVELOP FOR THE NEARSHORE WATERS
AND MAY ALSO SEE OCCASIONAL GALE FORCE GUSTS IN THE NEARSHORE
WATERS OVERNIGHT THRU DAYBREAK WEDNESDAY.
SFC RIDGE OVER THE OHIO VALLEY WILL CONTINUE TO DRIFT EAST
TONIGHT...WITH A TIGHTENING GRADIENT ALONG THE WESTERN EDGE. THIS
TIGHT GRADIENT WILL SLIDE OVER THE LAKE TONIGHT...PRODUCING
SOUTH/SOUTHWEST GALES BETWEEN 35-40KT OVERNIGHT. THE GRADIENT
CONTINUES TO SLIDE EAST WITH THE ARRIVAL OF A CLIPPER LOW
PRESSURE. THIS CLIPPER WILL ALLOW THE WINDS TO BECOME
WESTERLY...AND SHOULD SEE GALES COME TO AN END BY MID-MORNING WED.
HOWEVER THE GRADIENT WILL REMAIN RELATIVELY STRONG AND PRODUCE
WINDS TO 30KT THRU MIDDAY WED BEFORE DIMINISHING TO 15 TO 25 KT BY
WED NIGHT.
THE NEXT WEATHER SYSTEM TO BRING A STRONG GRADIENT TO THE LAKE
WILL ARRIVE SAT...AND LIKELY PRODUCE WINDS TO 30KT. IT IS POSSIBLE
A FEW GUSTS TO GALE FORCE MAY OCCUR SAT.
THEN ANOTHER STRONG RIDGE OF HIGH PRESSURE WILL SLIDE SOUTH FROM
CENTRAL CANADA FOR THE SECOND HALF OF THE WEEKEND AND MAY BRING A
TIGHT GRADIENT TO THE LAKE.
BEACHLER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 AM WEDNESDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 10 PM WEDNESDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion
National Weather Service Lincoln IL
1153 PM CST Tue Dec 24 2013
.DISCUSSION...
ISSUED 859 PM CST Tue Dec 24 2013
Plan to update forecast to reduce snow chances tonight and
Christmas morning. WAA/isentropic lift ahead of main clipper wave
is rapidly shifting east of the area. This forcing has done little
more than develop a deck of mid clouds locally. Forcing with the
upper wave itself is expected to arrive overnight into the morning
hours. There is currently very little snow occurring with the wave
right now, at least with the portion of the wave likely to impact
central Illinois, and the latest HRRR and 00Z NAM have trended
drier.
Low temperatures for the night have likely already been attained,
with good southerly flow helping temperatures to be steady or
slowly rise through the night. This portion and the remainder of
the short term forecast is in good shape and only minor tweaks are
needed for the latest hourly trends.
Bak
&&
.AVIATION...
ISSUED 1153 PM CST Tue Dec 24 2013
Cigs continue to thicken/lower across the central Illinois
terminals this evening as a clipper system begins to move across
the area. Expect conditions to degrade to MVFR by morning, possibly
aided by some light snow from the clipper. At this point, KPIA and
KBMI appear most likely to see some snow. While cloud conditions
are not entirely clear as the clipper departs later on Christmas
Day, plan to keep most terminals MVFR through the end of the 06Z
TAF valid time.
Bak
&&
.PREV DISCUSSION...
ISSUED 250 PM CST Tue Dec 24 2013
Very few changes needed to the forecast as the models remain
fairly consistent and in pretty good agreement throughout much of
the forecast period. Periodic shots of cold air with no major
storms, followed by brief warm-ups will be the main weather trend
for the upcoming week.
SHORT TERM...Tonight through Thursday
High pressure, which brought sub-zero readings to parts of central
Illinois this morning, was centered in southwest IN early this
afternoon. A southerly wind flow has already developed in
Illinois, and this will continue to increase through the evening
and overnight. The result will be slowly rising temperatures
through the night and into Christmas morning.
A clipper system in the northern Plains and its associated weak
surface low in north central Nebraska will shift to the ESE
tonight, spreading light snow into west central IL mainly after
midnight. The axis of the light snow will shift east of the I-55
corridor around daybreak, with lingering flurries to the west. By
late morning the snow should come to an end in much of east
central Illinois, with some lingering flurries from PIA-DEC-MTO-
Robinson. Most areas can expect around 0.5" or less of snow,
except in locations from Canton to just north of Bloomington where
1.0 to 1.5 inches are likely. The snow should be rather fluffy and
will blow around quite a bit with a southwest wind of 10 to 15 mph.
Partial clearing is then expected in the wake of the clipper
system with temperatures in the lower to middle 30s. Another
clipper system will follow on the heels of the first one later on
Christmas Day, but the measurable snow should stay well north of
central IL. This system will bring central Illinois a glancing
blow of colder air, so highs on Thursday will be a bit cooler
along and north of I-74. The rest of central and SE IL can expect
highs Thursday to be very similar to Wednesday`s.
LONG TERM...Friday through Tuesday
Overall, the medium and long range models are in pretty good
agreement with the mean upper level flow from the weekend into
early next week. By Friday, the upper level trough axis in the
eastern U.S. will breakdown and become flatter/more westerly. This
will allow temperatures to warm slightly Friday, with a nice warm-
up well into the 40s expected Saturday. Locations north of I-74,
however, may have some lingering snow which could keep
temperatures down in the upper 30s.
Both the GFS and European agree that the main longwave trough will
re-establish itself in the eastern U.S. by early next week.
However, they arrive at the solution differently - particularly
Sunday into Monday. The GFS is weaker with the trough early on,
and redevelops the longwave gradually. The European is stronger and
sharper with the shortwaves that carve out the new trough, which
results in a solution of light snow Sunday in the upper Midwest
and northern IL. Low level moisture will be quite low, and due to
the lack of persistence in the European model with this scenario
will hold of on mentionable PoPs for now, and keep the forecast in
the slight chance category.
Both models do agree, however, that another shot of very cold air
is in store for the Midwest by late Sunday and lasting into New
Year`s Eve with lows in the single digits to lower teens, and
highs in the teens to lower 20s.
Miller
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1201 AM EST WED DEC 25 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 438 PM EST TUE DEC 24 2013
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOWS SHRTWV RDG AXIS
MOVING INTO THE WRN LKS BTWN DEPARTING TROF IN THE SE GRT LKS
RESPONSIBLE FOR LES THE PAST FEW DAYS AND A PAIR OF SHRTWVS DIGGING
SEWD THRU SCENTRAL CANADA/THE NRN ROCKIES E OF MEAN RDG NEAR THE W
COAST. WITH SFC HI PRES BLDG ACRS THE AREA...LINGERING LES NEAR LK
SUP HAS DIMINISHED AND PUSHED INTO THE OPEN WATERS AS THE FLOW IS
SHIFTING TO THE SSW IN ADVANCE OF THE SFC LO PRES TROF IN THE NRN
PLAINS ASSOCIATED WITH THE TWO CLIPPER SHRTWVS. THE 12Z INL/MPX
RAOBS SHOWED A VERY DRY AIRMASS WITH PWATS UNDER 0.10 INCH...SO
SKIES ARE TURNING MOSUNNY AT MOST PLACES AS THE SSW FLOW SHIFTS
LINGERING LO CLDS BACK OUT OVER LK SUP. MID CLDS IN ADVANCE OF
APRCHG CLIPPER SHRTWVS/SFC TROF ARE PUSHING EWD THRU MN...WITH SN
FALLING OVER NW MN AND THE ERN DAKOTAS. ALTHOUGH THIS SN HAS BEEN
MDT AT SOME PLACES UNDER THE SHARPER H85-5 QVECTOR CVNGC...THE
COVERAGE APPEARS TO BE LIMITED BY ABSENCE OF SGNFT MSTR INFLOW.
MAIN FCST CONCERNS IN THE SHORT TERM ARE EXPECTED POPS/SN AMOUNTS
LATE TNGT AND XMAS MRNG ASSOCIATED WITH UPSTREAM CLIPPER SHRTWVS AND
GOING WINTER STORM WATCH OVER THE ERN CWA/NEED FOR ANY NEW HEADLINES.
TNGT INTO XMAS DAY...UPR TROF TO THE NW IS FCST TO SHIFT TO THE SE
AND STRETCH FM NW ONTARIO THRU MN AND INTO THE CENTRAL PLAINS BY 12Z
WED. MODELS SHOW PCPN IN ADVANCE OF THIS TROF ARRIVING OVER THE WRN
CWA LATE THIS EVNG AND PUSHING TO THE E...WITH A 6-9 PERIOD OF SN AT
MOST LOCATIONS BEFORE THE SN DIMINISHES OVER THE W 09-12Z WED AND BY
ABOUT 18Z WED OVER THE ERN CWA FOLLOWING DEPARTURE OF DEEP LYR
QVECTOR CNVGC. MAIN NEGATIVES FOR SGNFT SN FALL INCLUDE FCST SHARPER
H85-5 QVECTOR CNVGC/SHARPER H7 UVV ASSOCIATED WITH INCOMING OUT OF
PHASE SHRTWVS FOCUSING TO THE S OF UPR MI... LACK OF SGNFT MSTR
INFLOW WITH ONLY ABOUT 1.5-2 G/KG SPECIFIC HUMIDITY NEAR H7...AND
LIMITED RESIDENCE OF TIME OF PCPN. ONE FACTOR IN FAVOR OF SOMEWHAT
HIER SN AMOUNTS IS FCST DEEP DGZ THAT MAY BOOST SN/WATER RATIOS AS
HI AS 20-25:1. CONSIDERING MODEL QPF 0.05-0.15 INCH...EXPECT 1 TO 3
INCHES OF SN. THE ONE EXCEPTION WL BE OVER THE ERN CWA DOWNWIND OF
LK MI...WHERE INCRSG SSW FLOW UP THE LENGTH OF LK MI IN THE PRESENCE
OF DEEP MSTR/H85 TEMPS ARND -15C WL BRING A PERIOD OF HEAVIER LK
ENHANCED SN. PRESENCE OF LINGERING BAND IN NRN LK MI AS SHOWN ON
RECENT STLT IMAGERY EARLY THIS AFTN INCREASES CONFIDENCE IN THIS
FCST. BULK OF HIER RES MODELS SHOW THE HEAVIER LES BAND IMPACTING
FAR SE SCHOOLCRAFT COUNTY/SRN LUCE COUNTY IN THE 09Z-15Z WED TIME
FRAME. WITH MODEL QPF RANGING FM 0.25 INCH TO AS MUCH AS 0.40 INCH
AND DEEP DGZ SHOWN ON THE FCST SDNGS...EXPECT AT LEAST A HI END ADVY
SNFALL IN THIS AREA. FCST SDNGS ALSO SHOW A PERIOD OF NEARLY
UNIDIRECTIONAL SSW FLOW WITHIN THE MIXED LYR FOR A FEW HRS DURING
TIME OF PEAK SN INTENSITY. GIVEN THESE FVRBL CONDITIONS...OPTED TO
UPGRADE WATCH TO A WRNG FOR LUCE COUNTY...WHERE HEAVIER LES BAND IS
MOST LIKELY TO RESIDE THE LONGEST AND DROP UP TO 9 TO PERHAPS 10
INCHES ALONG M-28 E OF ERY. WENT WITH AN ADVY FOR SCHOOLCRAFT COUNTY
WITH POTENTIAL FOR SOME LK ENHANCEMENT...ESPECIALLY E OF SENEY AND
MANISTIQUE. AS FOR TEMPS...ARRIVAL OF THICKER CLDS/STEADY S WIND WL
ALLOW FOR ONLY A RELATIVELY SMALL TEMP DIP EARLY OVER THE W HALF.
BUT TO THE E...EXPECT TEMPS TO FALL QUICKLY OVER THE INTERIOR ERN
CWA THIS EVNG BEFORE THE CLDS AND STEADY S WINDS ARRIVE LATER.
LATER ON XMAS DAY...AS THE UPR TROF AND SFC REFLECTION SHIFT SLOWLY
THRU THE UPR GREAT LKS...THE LLVL FLOW IS PROGGED TO VEER TOWARD THE
W. THIS WSHFT TO A MORE WSW DIRECTION WL END THE THREAT OF LK
ENHANCED SHSN OVER THE E BY EARLY AFTN BUT CAUSE SOME LES TO DVLP
OVER THE W IN THE AFTN AS H85 TEMPS DIP BACK NEAR -18C BY 00Z THU.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 438 PM EST TUE DEC 24 2013
WEDNESDAY NIGHT...LOW LEVEL CONV ALONG A COLD FRONT AND 850
MB TEMPS DROPPING FROM -15C TO -19C WILL BRING AN INCREASE IN LES
INTO NORTHWEST UPPER MICHIGAN WED EVENING AND OVER ERN CWA
OVERNIGHT. EVEN WITH A FAVORABLE PLACEMENT OF THE DGZ IN THE
CONVECTIVE LAYER GIVING SLR VALUES NEAR 25/1...INVERSION HEIGHTS
NEAR 6K FT AND STEADILY VEERING WINDS SHOULD KEEP ACCUMULATIONS IN
THE 2 TO 4 INCH RANGE...WITH THE GREATEST AMOUNTS IN THE HIGHER
TERRAIN FROM CALUMET TO TWIN LAKES AND NORTH OF M-28 EAST OF
MUNISING.
THU INTO THU NIGHT...NW FLOW LES WILL GRADUALLY DIMINISH AS A WEAK
SFC RIDGE BUILDS FROM THE UPPER MS VALLEY INTO THE WRN LAKES
BRINGING BACKING WINDS AND LOWERING INVERSION HEIGHTS. THE STRONGEST
FORCING AND MOST FAVORABLE WAA/ISENTROPIC LIFT ASSOCIATED WITH A
WEAK CLIPPER SHORTWAVE TROUGH IS EXPECTED TO REMAIN SOUTH OF THE
UPPER MICHIGAN.
FRI...THE ECMWF WAS MORE AGGRESSIVE WITH POTENTIAL FOR SOME LIGHT
SNOW BY LATE FRI WITH THE WAA/ISENTROPIC LIFT PATTERN DEVELOPING
AHEAD OF THE NEXT CLIPPER SHRTWV AND SFC LOW MOVING TOWARD NW
ONTARIO COMPARED TO THE GFS/GEM. WITH LOW CONFIDENCE IN ANY
PCPN...ONLY SLIGHT/CHANCE POPS WERE INCLUDED...MAINLY OVER THE EAST.
SAT INTO SAT NIGHT...A BRIEF WARMUP IS EXPECTED SATURDAY AS UPPER MI
WILL BE IN THE WARMER SECTOR AHEAD OF THE NEXT LOW. TEMPS SHOULD
CLIMB ABOVE NORMAL WITH HIGHS AROUND 30. MODEL DIFFERENCES WERE EVEN
GREATER BY SATURDAY NIGHT...AS THE ECMWF WAS SLOWER/DEEPER WITH
SHRTWV AND SFC LOW MOVING THROUGH THE NRN GREAT LAKES. REGARDLESS OF
MODEL DIFFERENCES...A COLD FRONT MOVING THROUGH WITH WINDS VEERING
SHARPLY TO THE NNW SHOULD BRING LES OR LAKE ENHANCED SNOW INTO NRN
UPPER SAT NIGHT.
SUN-TUE...ANOTHER VERY COLD ARCTIC AIRMASS WILL DOMINATE THE REGION
THROUGH THE PERIOD WITH LES EXPECTED FOR NW WIND FAVORED SNOWBELTS.
WIND CHILL VALUES NEAR ADVISORY WILL BE POSSIBLE OVER THE WEST HALF
BOTH EARLY MONDAY AND TUESDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1200 AM EST WED DEC 25 2013
IFR CONDITIONS WITH LIGHT SNOW WILL CONTINUE EARLY THIS FORECAST
PERIOD AS A TROF MOVES ACROSS THE AREA. AS THE SN DIMINISHES W-E BY
SUNRISE ON WED...MVFR SC CIGS WL LINGER. AS THE WEAKER FLOW VEERS
TOWARD THE W LATER ON WED MRNG...MORE SHSN/IFR VSBYS MAY IMPACT CMX
BY EARLY WED EVENING.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 438 PM EST TUE DEC 24 2013
AS THE PRES GRADIENT TIGHTENS OVER LAKE SUPERIOR THIS EVENING
BETWEEN DEPARTING SURFACE HI PRES RIDGE AND AN APPROACHING LO PRES
TROF...OPTED TO MAINTAIN GOING GALE WARNING FOR THE ECENTRAL
PORTIONS OF THE LAKE. AWAY FROM THIS FAVORED AREA...SOME GALE FORCE
GUSTS WILL BE POSSIBLE. CLOSER APPROACH AND THEN PASSAGE OF LO PRES
TROF AND WEAKER GRADIENT ON WED WILL CAUSE THE GALES TO DIMINISH AS
THE WINDS VEER TOWARD THE W-NW. NORTHWEST TO NORTH GALES WILL AGAIN
BE POSSIBLE SATURDAY NIGHT BEHIND AN ARCTIC COLD FRONT. HEAVY
FREEZING SPRAY IS ALSO EXPECTED INTO EARLY NEXT WEEK.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR MIZ014-
085.
WINTER STORM WARNING UNTIL 1 PM EST THIS AFTERNOON FOR MIZ007.
LAKE SUPERIOR...
GALE WARNING UNTIL 7 AM EST THIS MORNING FOR LSZ266.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...JLB
AVIATION...07
MARINE...KC
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
338 AM CST WED DEC 25 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 337 AM CST WED DEC 25 2013
TROUGHING AND CYCLONIC FLOW WILL DOMINATE THE SHORT TERM...WHICH
MEANS LOTS OF CLOUDS AND BOUTS OF LIGHT SNOW WILL DOMINATE THE NEXT
24 HOURS. LOOKING AT WATER VAPOR IMAGERY OVERLAID WITH RAP H5
VORTICITY YOU CAN SEE A COUPLE OF WAVES UPSTREAM IN THE NW FLOW THAT
WILL IMPACT US. THE FIRST IS CURRENTLY OVER ERN NODAK AND ALREADY
HAS SNOW MOVING ACROSS ERN SODAK AND NW MN AND WILL BE ARRIVING IN
THE MPX CWA SHORTLY. THE SECOND WAVE IS UP OVER NRN SASKATCHEWAN AND
WILL BE WORKING ACROSS MN THIS AFTERNOON. THESE UPPER WAVES WILL BE
WORKING WITH AN ELEVATED WARM FRONT IN THE H85-H7 LAYER TO THROW
SEVERAL BOUTS OF LIGHT SNOW OUR DIRECTION THROUGH THE PERIOD. THE
BEST BURST WILL BE THE INITIAL ONE THIS MORNING. THE HEAVIEST SNOW
HAS BEEN ALONG THAT ELEVATED WARM FRONT OVER ERN SODAK OVERNIGHT AND
FOLLOWED THE HRRR FOR BRINGING THIS SNOW DOWN THE MN RIVER THIS
MORNING. HAVE ENOUGH QPF OUT OF IT TO GET 0.5 TO 1 INCH SNOW AMOUNTS
FROM WC MN DOWN THE MN RIVER INTO SE MN. FOR THE REST OF THE
PERIOD...THE PATTERN IN PLACE LEADS TO LOW CONFIDENCE ON WHEN/WHERE
THESE LITTLE BURSTS OF SNOW WILL COME DOWN...SO THERE ARE LOTS OF
SMALL POPS THROUGH 9Z TONIGHT...WHICH IS WHEN THE SREF AND HIRES
MODELS FINALLY SHOW SNOW CHANCES EVACUATING THE MPX CWA...FOR A
SHORT TIME ANYWAYS.
TEMPERATURES WILL BE TRICKY THIS PERIOD AS WELL THANKS TO A SFC WARM
FRONT THAT AT 3AM WAS NEAR A ROSEAU/LONG PRAIRIE/TWIN CITIES/ALBERT
LEA LINE. TEMPERATURES EAST OF THIS BOUNDARY HAVE REMAINED IN THE
SINGLE DIGITS...WITH TEMPERATURES SLOWLY RISING INTO THE TEENS AND
EVEN LOWER 20S BY THE TIME YOU GET TO THE MN/SD BORDER. THE COLD
FRONT WAS ALIGNED FROM A WEAK SFC LOW NEAR GRAND FORKS BACK NW INTO
CENTRAL SASKATCHEWAN. THE WARM SECTOR ACROSS THE DAKOTAS HAS BEEN
QUITE IMPRESSIVE THIS MORNING...WITH SEVERAL LOCATIONS ACROSS THE
CENTRAL DAKOTAS WARMING TO BETWEEN 32 AND 34 DEGREES /ABOUT 35
DEGREES WARMER THAN THIS TIME 24 HOURS AGO!/. THE QUESTION FOR
TODAY...IS HOW MUCH OF THIS WARM SECTOR CAN WE GET INTO THE MPX CWA.
THE CORE OF THE WARMEST AIR LOOKS TO DROP SOUTHWEST OF THE MPX
CWA...BUT WE SHOULD STILL SEE TEMPS RISE INTO THE UPPER 20S ACROSS
WRN MN THIS MORNING...BEFORE THE COLD FRONT ARRIVES THIS AFTERNOON
TO START SENDING TEMPERATURES THE OTHER DIRECTION.
FOR TONIGHT THE TWO VARIABLES TO WATCH ARE WHAT HAPPENS WITH CLOUD
COVER AND WHERE DOES THAT COLD FRONT END UP. AS FOR THE FRONT...MOST
MODELS SHOW THE FRONT BECOMING STATIONARY ACROSS SW MN...WITH
ANOTHER PUNCH OF ARCTIC AIR SLIDING DOWN ACROSS AREAS MAINLY NORTH
OF I-94. THIS WILL KEEP TEMPERATURES TONIGHT IN THE MN RIVER VALLEY
ON SOUTH UP IN THE TEENS...BUT BACK NORTH OF I-94...IF SKIES CAN
STAY SUFFICIENTLY CLEAR...WE COULD SEE MORE WIDESPREAD DOUBLE DIGIT
LOWS BELOW ZERO. IT/S NOT OUT OF THE REAL OF POSSIBILITY TO SEE A
NEARLY A NEARLY 30 DEGREE SPREAD IN LOWS TONIGHT ACROSS THE MPX
CWA...WITH LOWS AROUND 15 ABOVE OUT IN WRN MN AND AROUND 15 BELOW
ALONG THE US-8 CORRIDOR IN WRN WI.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 337 AM CST WED DEC 25 2013
THE FORECAST WARM UP FOR THE LATER HALF OF THE WEEK STILL LOOKS TO
BE ON SCHEDULE. SHOULD SEE MODERATING TEMPERATURES INTO SATURDAY
WITH ANOTHER WAFT OF PACIFIC AIR MOVING THROUGH...AHEAD OF NEXT
ARCTIC COLD FRONT. MODELS TREND ANOTHER SHOT OF SNOW ASSOCIATED
WITH THE INITIAL PACIFIC AIR INTRUSION ON THURSDAY. AT THE
MOMENT...HAVE INCLUDED A SMALL LIKELY POP AREA OVER THE NORTHEAST
CWA. SIGNIFICANT MOISTURE APPEARS TO BE LACKING AND MOST MODELS
HAVING TROUBLE SATURATING AS THE PRECIPITATION BAND MOVES FARTHER
EAST. ANY SNOWFALL SHOULD REMAIN LIGHT FOR THIS SYSTEM.
DO EXPECT SOME LOWER 30S AT LEAST AHEAD OF THE ARCTIC BOUNDARY AS
THAT ARRIVES SATURDAY AFTERNOON. WITH STEEP LOW LEVEL LAPSE
RATES...STRONG WIND GUSTS EXPECTED TO MATERIALIZE. 35 KT WIND
GUSTS LOOK LIKELY AS THE SYSTEM MOVES THROUGH. THE BETTER CHANCE
OF SNOW SHOWERS SHOULD RIDE FARTHER EAST...BUT IF THEY DO COINCIDE
WITH THE STRONGEST WINDS...COULD SEE NEAR BLIZZARD CONDITIONS
DEVELOP OVER THE SOUTHWEST/MINNESOTA RIVER VALLEY REGION SATURDAY
AFTERNOON/EVENING. HAVE CONTINUED TO INCLUDE SOME BLOWING SNOW
OVER THE REGION FOR THIS PERIOD...INTO SUNDAY.
THE NEXT SURGE OF ARCTIC AIR DROPS OVER THE REGION SUNDAY AND
LINGERS THROUGH MUCH OF THE COMING WEEK. NORTHWEST FLOW PATTERN
WILL LEAVE THE REGION IN THE FAVORABLE AREA FOR MORE LIGHT/FLUFFY
SNOW EVENTS. MONDAY NIGHT INTO TUESDAY NIGHT LOOKS LIKE THE NEXT
BEST CHANCE OF SOME LIGHT SNOW. HAVE LOW POPS FOR NOW. WILL HOLD
OFF ON HIGHER POPS FOR NOW...TO GET BETTER TIMING AS WE GET CLOSER
TO THE EVENT. WIND CHILLS WILL ONCE AGAIN BECOME AN ISSUE AS THE
COLD AIR ARRIVES AS WELL. THE 00Z ECMWF SHOWS LITTLE MODERATION IN
TEMPERATURES IN THE LONGER TERM...WHICH WOULD TAKE US INTO THE
FIRST WEEK OF THE NEW YEAR.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1137 PM CST TUE DEC 24 2013
MVFR CONDITIONS FOR MUCH OF THE OVERNIGHT AND CHRISTMAS
DAY...EXCEPT TOWARD AXN WHERE IFR WILL PREVAIL. GUIDANCE IS VERY
PESSIMISTIC WITH CIGS AND VSBYS OVERNIGHT...PROBABLY DUE TO THE
RESIDUAL EFFECTS OF HEAVY SNOW THIS EVENING. DO NOT BELIEVE ATTM
DENSE FOG OR LIFR CIGS ARE IN THE CARDS. ANOTHER BATCH OF SNOW
WILL SLIDE SOUTHEAST ACROSS MN LATE TONIGHT AND CHRISTMAS MORNING
WITH A 2-3 HOUR WINDOW OF 2-4SM -SN. FOLLOWING THAT...GUSTY
NORTHWEST WINDS WILL BRING A GOOD CHANCE OF BLOWING SNOW TO
WESTERN MN.
KMSP...CIGS WILL TEETER BETWEEN 015 AND 020 FOR MUCH OF THE
OVERNIGHT...WITH SUB 015 CIGS LIKELY ACCOMPANYING THE NEXT ROUND
OF SNOW EARLY WEDNESDAY. IMPROVING CONDITIONS THEREAFTER.
/OUTLOOK FOR KMSP/
THU...VFR. CHANCE MVFR CIGS/VSBYS IN -SN. WINDS S AT 5 KTS.
FRI...VFR. WINDS SW 5-10 KTS.
SAT...VFR. CHC MVFR/-SN LATE. WINDS SW 5-10 KTS BECOMING NW
20G30 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...MPG
LONG TERM...DWE
AVIATION...BORGHOFF
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
1128 PM CST TUE DEC 24 2013
.AVIATION...
4KM WRF AND HRRR SHOW STRATUS ADVECTING NORTH ON STRONG LLVL JET.
NAM/RAP SOUNDINGS ALSO INDICATE THIS ALTHOUGH GFS DOES NOT. SINCE
CLOUDS ARRIVE AT METROPLEX AFTER SUNRISE HAVE INDICATED A STRATUS
LAYER LIFTING TO VFR AFTER THE FROPA NEAR NOON. AT WACO SOUNDINGS
INDICATE A VERY SHALLOW IFR LAYER THAT WILL ALSO BURN OFF AFTER
SUNRISE. 84
&&
.UPDATE...
A COLD FRONT CONTINUES TO MOVE SOUTH THROUGH OKLAHOMA AND THE
TEXAS PANHANDLE THIS CHRISTMAS EVE. IMPRESSIVE PRESSURE RISES ON
THE ORDER OF 5 TO 6 MB ACROSS THE SOUTHERN FRONT RANGE. THE FRONT
SHOULD SURGE SOUTH THROUGH THE SOUTHERN HIGH PLAINS AND CHANGE
ORIENTATION A BIT...BUT STILL REACH THE NORTHWEST ZONES AROUND
SUNRISE.
SOME PATCHY FOG WILL BE POSSIBLE AHEAD OF THE FRONT...MAINLY
ACROSS THE WESTERN HALF OF NORTH TEXAS OVERNIGHT AND CHRISTMAS
MORNING. THE FOG WILL NOT BE AS DENSE AS IT WAS THIS MORNING AND
WE DO NOT ANTICIPATE ANY IMPACTS FROM FREEZING FOG.
THE CURRENT FORECAST IS IN GOOD SHAPE OVERALL SO WILL ONLY MAKE
SOME MINOR ADJUSTMENTS TO THE HOURLY GRIDS.
79
&&
.PREV DISCUSSION... /ISSUED 249 PM CST TUE DEC 24 2013/
AFTER A FOGGY MORNING ACROSS THE NORTHWESTERN PORTIONS OF THE
FORECAST AREA...SKIES HAVE CLEARED WITH TEMPERATURES WARMING INTO
THE 40S AND 50S. SOUTHERLY WINDS HAVE RETURNED WHICH HAVE HELPED
WARM TEMPERATURES A FEW DEGREES VERSUS THIS TIME YESTERDAY. A
SHORTWAVE TROUGH IS CURRENTLY PUSHING INTO THE CENTRAL PLAINS AND
THIS TROUGH WILL SUPPORT ANOTHER FROPA FOR NORTH TEXAS TOMORROW.
AHEAD OF THE FRONT...SURFACE WINDS WILL REMAIN LIGHT OVERNIGHT...
AND WITH LEFT OVER LOW-LEVEL MOISTURE ANOTHER ROUND OF FOG IS
POSSIBLE. DO NOT THINK VISIBILITIES WILL BE AS LOW AS THIS MORNING
DUE TO SLIGHTLY HIGHER WIND SPEEDS. WILL NOT MENTION FREEZING
FOG...AS LOWS IN THE NORTHWESTERN ZONES WILL BE CLOSER TO 30 AND
NOT IN THE UPPER 20S...SO CHANCES FOR IMPACTS WOULD BE LOWER AS
WELL. THE FOLLOWING SHIFTS MAY NEED TO ASSESS OR CHANGE THE
FORECAST IF DENSE FOG LOOKS MORE LIKELY OR TEMPERATURES BECOME
COLDER THAN FORECASTED.
THE FRONT IS EXPECTED TO PUSH INTO THE AREA LATE TOMORROW MORNING
AND AFTERNOON. STRONG VERTICAL MOTIONS WILL BE OCCURRING ACROSS
THE AREA AS THE TROUGH NEARS THE REGION OVERNIGHT AND
TOMORROW...BUT MOISTURE REMAINS SCOURED AS THE GULF OF MEXICO
REMAINS SHUT OFF. THEREFORE...NO RAIN IS EXPECTED WITH THIS FRONT.
THE FRONT WILL ACTUALLY HAVE LITTLE IMPACT TO OUR WEATHER. HIGHS
FRIDAY WILL BE INTO THE UPPER 50S WITH LOWER 60S BY SATURDAY
AFTERNOON.
ANOTHER PIECE OF ENERGY WILL MOVE INTO THE REGION FRIDAY...BUT NO
RAIN IS EXPECTED. WITH ONE FROPA AFTER ANOTHER...MOISTURE WILL
REMAIN TOO LOW TO SUPPORT PRECIPITATION. A LARGER TROUGH IS
EXPECTED TO DROP INTO THE CENTRAL AND EASTERN CONUS SATURDAY AND
SUNDAY. THIS TROUGH WILL SEND YET ANOTHER...AND STRONGER COLD
FRONT INTO THE FORECAST AREA SUNDAY. OVER THE PAST DAY OR TWO...WE
HAVE BEEN TALKING ABOUT THE CHANCES FOR LIGHT RAIN OR DRIZZLE IN
THE EASTERN ZONES WITH THE FROPA...BUT THIS SEEMS LESS LIKELY.
LATEST FORECAST SOUNDINGS SHOW SATURATION OF THE LOWER LEVELS OF
THE ATMOSPHERE WILL NOT OCCUR UNTIL AFTER FROPA AND WINDS WITHIN
THIS LAYER WILL ALREADY BE NORTHERLY BY THE TIME SATURATION
OCCURS. THIS WOULD SUPPORT DOWNWARD MOTIONS AND WOULD NOT LEAD TO
THE PRODUCTION OF PRECIPITATION. THIS FRONT WILL KEEP TEMPERATURES
COLDER THAN NORMAL...WITH FREEZES EXPECTED FOR MUCH OF THE AREA
MONDAY AND TUESDAY MORNING.
HAMPSHIRE
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 32 52 32 54 34 / 0 0 0 0 0
WACO, TX 32 54 33 54 32 / 0 5 0 5 5
PARIS, TX 28 50 30 54 31 / 0 0 0 0 5
DENTON, TX 32 51 29 54 31 / 0 0 0 0 0
MCKINNEY, TX 29 51 30 54 31 / 0 0 0 0 0
DALLAS, TX 34 52 33 54 35 / 0 0 0 0 0
TERRELL, TX 31 53 31 54 31 / 0 0 0 0 5
CORSICANA, TX 32 56 33 54 33 / 0 5 0 5 5
TEMPLE, TX 32 55 34 55 33 / 0 5 0 5 5
MINERAL WELLS, TX 31 52 28 55 30 / 0 0 0 0 0
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
/
Area Forecast Discussion
National Weather Service Lincoln IL
949 AM CST Wed Dec 25 2013
.DISCUSSION...
ISSUED 948 AM CST Wed Dec 25 2013
Initial upper wave currently pushing through central Illinois.
Earlier light snow ahead of this wave is now well off to the west.
However, a faster shortwave, currently diving into northwest Iowa,
has been producing some light snow ahead of it, from central Iowa
to western Wisconsin. Morning models showing the bulk of the snow
with this feature tracking just to our north, but the NAM and RAP
models show potential for perhaps a tenth or two of snow north of
I-74 during the evening hours. Have made some updates to the snow
trends in the forecast, namely to add some low PoP`s in the far
northern CWA this evening. Have also removed most of the flurries
after midnight, as the shortwave should be well east of us by that
point. Temperature forecasts generally on track and only needed
some minor tweaks.
Geelhart
&&
.AVIATION...
ISSUED 556 AM CST Wed Dec 25 2013
MVFR clouds will prevail for the first few hours of this TAF
period as a fast moving clipper produces light snow for a period
of an hour or so. Snow has already ended at PIA, and is just
affecting SPI. Over the next 2 hours, BMI, DEC and CMI will see
the snow move through. IFR clouds are poised to develop 2 hours
after the snow ends, based on observation trends upstream. The NAM
and RAP soundings show IFR conditions could persist into the
afternoon, and possibly until near sunset. MVFR conditions could
develop as mixing increases this afternoon, but we generally held
off the return to MVFR clouds until 22-23z.
Some clearing should develop from west to east this evening, as
the drier air returns to lower levels. Clearing could reach PIA as
early as 01z and progress to CMI by 07z.
Winds will be primarily southwest until this evening when they
shift to the west and increase from around 10-12kt to 14-16kt.
Shimon
&&
.PREV DISCUSSION...
ISSUED 209 AM CST Wed Dec 25 2013
No major storm systems are anticipated across central Illinois
over the next week, as a prevailing northwesterly flow pattern
brings periodic flurries/very light snow and bouts of very cold
air.
SHORT TERM...Today through Friday
First weak system embedded within the northwesterly flow is
currently approaching the Mississippi River as an elongated
vorticity max stretching from Wisconsin to the Texas panhandle.
This feature has been shearing/weakening as it tracks eastward,
and with limited moisture to work with, has produced only very
meager amounts of light snow across parts of central and northern
Iowa. Stronger lift and steadier snows have been confined further
north across Minnesota into Wisconsin. Despite models insisting on
precip development further south, have not seen much evidence
upstream over Missouri, so have decided to downplay the snow
chances this morning. Will maintain low chance PoPs along/north of
the I-74 corridor through midday, where a dusting is possible.
Further south, will only mention scattered flurries across the
remainder of the KILX CWA.
Once the initial wave passes, another disturbance currently
dropping into North Dakota will skirt across northern Illinois
this evening. Due to increasing synoptic lift ahead of this
feature, have added flurries to the forecast along/west of the
Illinois River late this afternoon, then everywhere tonight.
Upper pattern will begin to go zonal by the end of the week,
signaling a brief warming trend that will help boost highs well
into the 30s and even the lower 40s south of I-70 by Friday.
LONG TERM...Saturday through Tuesday
Warmest day of the forecast period will be Saturday, as
southwesterly winds ahead of an approaching Arctic cold front
allow temps to reach the 40s across the board. Models have been
consistent in bringing the cold front through central Illinois on
Sunday, with each run suggesting clouds and perhaps a few
snow-showers. Will carry low chance PoPs for snow on Sunday
accordingly. Once front passes, another chunk of very cold air
will arrive early next week as the upper flow pattern returns to
northwesterly. With 850mb temps progged to fall into the -12 to
-14C range, highs will drop back into the teens and lower 20s by
Monday. After that, will have to watch the next approaching
clipper system for late Monday into Tuesday. Latest models are
slower and a bit further north with this system, but still suggest
a period of light snow will be possible across the northern CWA
late Tuesday. Timing of these features this far out is quite
difficult, so will only mention very low chance POPs across the
north at this time.
Barnes
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
802 AM CST WED DEC 25 2013
.DISCUSSION...
330 AM CST
SYNOPSIS...A COUPLE QUICK SNOW SYSTEMS MOVE ACROSS THE REGION
THROUGH TONIGHT WITH 1 TO 2 INCHES EXPECTED PRIMARILY ALONG AND
NORTH OF I-88. A BRIEF WARM UP IS EXPECTED LATE THIS WEEK BEFORE
TEMPERATURES QUICKLY TUMBLE SUNDAY WITH ANOTHER CHANCE OF SNOW. FOR
EXAMPLE HIGH TEMPS SATURDAY WILL BE IN THE MID 30S TO THE LOW 40S
THEN LOW TEMPS SUNDAY NIGHT WILL VARY FROM -6 TO +8 ACROSS THE CWA.
ADDITIONAL CHANCES OF SNOW ARRIVE EARLY NEXT WEEK...WITH TUESDAYS
SYSTEM LOOKING THE MOST IMPRESSIVE.
TODAY AND TONIGHT...
THE LONGWAVE TROUGH AXIS STRETCHES FROM MINNESOTA THROUGH NEW MEXICO
THIS MORNING WITH A SHORTWAVE TRAVELING A BIT QUICKER THAN THE
LARGER WAVE. THE SHORTWAVE IS OVER EASTERN IOWA AND ASSOCIATED WITH
SOME LIGHT RETURNS ON RADAR ALONG THE IL/IA STATE LINE. GUIDANCE
CONTINUES TO BACK OFF ON HOW MUCH SNOW WILL DEVELOP AHEAD OF THE
SHORTWAVE...BUT DECIDED TO KEEP SNOW GOING IN THE FORECAST. TEMPS
HAVE COME UP TO AROUND 20 DEGREES WITH THE DGZ AT OR NEAR THE
SURFACE. FORCING EXTENDS THROUGH THE DGZ FOR A COUPLE OF HOURS WITH
A SATURATED SOUNDING AT THOSE LAYERS. HOWEVER...GIVEN THE DOWN PLAY
IN GUIDANCE AND HOW SNOW IS STRUGGLING TO DEVELOP NOW...LOWERED
STORM TOTAL SNOW AMOUNTS. WENT FOR AN INCH NORTH OF
I-88...ESPECIALLY ALONG THE IL/WI STATE LINE...WITH AN INCH OR LESS
EXPECTED SOUTH OF THAT.
SOUTH TO SOUTHWEST WINDS GUSTING UP TO 20 KT COULD RESULT IN A
LITTLE BLOWING SNOW...BUT NOT OVERLY CONCERNED SINCE ONLY EXPECTING
AN INCH TODAY. THE SNOW THAT DOES FALL WILL BE VERY DRY WITH RATIOS
IN EXCESS OF 20:1. HIGH TEMPS WILL BE AT FREEZING DOWN SOUTH TO THE
MID 20S ALONG THE WI/IL STATE LINE. HOWEVER...WIND CHILLS WILL MAKE
IT FEEL LIKE SINGLE DIGITS ALONG THE WI/IL STATE LINE TO THE TEENS
DOWN SOUTH.
NEXT UP IS THE LOW CURRENTLY STRETCHING FROM HUDSON BAY THROUGH
NORTHWEST MINNESOTA. THE LOW PASSES OVER ONTARIO THIS AFTERNOON
WITH THE UPPER LEVEL TROUGH AXIS PASSING THROUGH THIS AFTN/EVENING.
EXPECTING ANOTHER BATCH OF SNOW SHOWERS TO FORM AHEAD OF THIS AS
WELL. HAVE SNOW ENTERING NORTH CENTRAL IL THIS AFTN WITH A BAND
SPREADING SOUTH EAST THROUGH THIS EVENING. THE DEPTH OF
MOISTURE IN THE DGZ IS MUCH BETTER WITH THIS SECOND DISTURBANCE AND
COULD SEE A QUICK HALF INCH TO INCH THROUGH THIS EVENING. THE
HIGHEST TOTALS ARE AGAIN EXPECTED ALONG THE IL/WI STATE LINE BECAUSE
THE FORCING STARTS OUT FARTHER NORTH AND DOES NOT MOVE INTO IL UNTIL
THE MOISTURE IS OVER INDIANA AND MICHIGAN.
FOR OVERNIGHT DID NOT MAKE ANY MAJOR CHANGES TO GOING LOW TEMPS.
NOT SURE HOW MUCH OF THE AREA WILL HAVE A FRESH SNOWPACK SO TEMPS
MAY HAVE TO BE LOWERED A BIT BY LATER SHIFTS. COLDER AIR ALOFT
MOVES IN BEHIND THE TROUGH AXIS...LESS THAN -8C AT 925 MB...AND
CLOUDS SHOULD THIN LATE TONIGHT. SO UPPER TEENS DOWN SOUTH TO
SINGLE DIGITS ACROSS NORTH CENTRAL IL IS EXPECTED. OVERNIGHT...MIN
WIND CHILLS WILL BE IN THE SINGLE DIGITS DOWN SOUTH TO AS LOW AS
-10F NORTH OF I-88.
THURSDAY AND FRIDAY...
NORTHWEST FLOW ALOFT IS EXPECTED EARLY THURSDAY BUT ANOTHER TROUGH
AXIS ROLLS THROUGH FRIDAY. AT THE SURFACE HIGH PRESSURE BUILDS
ACROSS THE SOUTHERN U.S. WITH ITS RIDGING PASSING OVER THE REGION
THURSDAY AFTN. KEPT A DRY FORECAST GOING FOR THIS PERIOD.
SOUTHWEST FLOW AND WAA RAISE 925 MB TEMPS TO NEAR 0C BY FRIDAY
MORNING...AND THEN TO AROUND +5 BY SATURDAY MORNING. THEREFORE HAVE
TEMPS INCREASING THROUGH FRIDAY TO AROUND 30 ALONG THE IL/WI STATE
LINE TO NEAR 40 ACROSS THE SOUTHERN PORTION OF THE CWA. OVERNIGHT
LOWS FRIDAY LOOK TO BE IN THE 20S.
SATURDAY AND SUNDAY...
THE NEXT WEAK LOW IS PUSHED SOUTH THROUGH THE CWA SATURDAY EVENING
AND NIGHT WITH THE UPPER LEVEL TROUGH AXIS ROTATING THROUGH SUNDAY
NIGHT. THE WARM UP CONTINUES ON SATURDAY...AND TEMPERATURES MAY
HAVE TO BE RAISED FURTHER SINCE GUIDANCE CONTINUES TO SUGGEST 925MB
TEMPS WILL WARM TO +4 TO +8C SATURDAY AFTERNOON. THAT RELATES TO
MAX TEMPS ON SATURDAY OF IN THE MID 30S TO LOW 40S. NOT EXPECTING
ANY PRECIP UNTIL BEHIND THE LOW AND ITS COLD FRONT/UPPER LEVEL
TROUGH AXIS SUNDAY.
FIRST...TEMPERATURES DROP THROUGH THE DAY ON SUNDAY WITH HIGH TEMPS
BEING MET EARLY SUNDAY MORNING. LOOKING AT TEMPS RANGING FROM
SINGLE DIGITS NEAR RFD TO LOW 20S IN NORTHWEST INDIANA BY EARLY
SUNDAY EVENING. SO EXPECTING ANY PRECIP THAT DOES FORM SHOULD BE
SNOW. TEMPS CONTINUE TO FALL WITH 925MB TEMPS AT -15 TO -20C BY
MONDAY MORNING. THEREFORE LOW TEMPS SUNDAY NIGHT WILL RANGE FROM
THE SINGLE DIGITS TO AROUND -5F. NORTHWEST WINDS AROUND 10 KT WILL
CREATE MIN WIND CHILLS BELOW ZERO SUNDAY NIGHT. THE COLDEST AREA
WILL BE NORTH OF I-88 WHERE WIND CHILLS LOWER THAN -20F ARE
POSSIBLE.
FOR SNOW...THE FORCING AND MOISTURE DO NOT SEEM ALL THAT IMPRESSIVE
AT THIS TIME SO NOT EXPECTING ANY MAJOR ACCUMULATION. GFS COBB
OUTPUT AGREES AS IT IS ONLY SHOWING A FEW TENTHS.
EXTENDED...MONDAY AND TUESDAY...
MONDAY REMAINS COLD AS THE UPPER LEVEL COLD AIR LINGERS
OVERHEAD...BUT WINDS TURN WSW AND BEGIN TO USHER IN WARMER AIR ALOFT
MONDAY NIGHT. HIGH TEMPS ON MONDAY WILL BE IN THE SINGLE DIGITS TO
THE LOWER TEENS AND WIND CHILLS DURING THE DAY BELOW ZERO. MIN WIND
CHILLS MONDAY NIGHT WILL ONCE AGAIN BE BELOW ZERO. HIGH PRESSURE
PASSES OVER MONDAY NIGHT WITH ANOTHER CLIPPER ARRIVES TUESDAY. THIS
SYSTEM LOOKS DARE I SAY VIGOROUS...FOR BEING A WEEK AWAY. GUIDANCE
DIFFERS SLIGHTLY SO ONLY UPPED POPS INTO THE CHANCE RANGE...BUT
LOOKING AT LONG RANGE COBB FOR FUN INDICATES SNOWFALL OF A FEW
INCHES.
JEE
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 14Z...
* 1000-1500 FT CIGS THROUGH MUCH OF TODAY WITH THE POTENTIAL TO
DIP DOWN TO IFR AT TIMES AFTER 16Z.
* CHANCE FOR LIGHT SNOW THIS AFTERNOON AND EVE.
BEACHLER/MTF
//DISCUSSION...UPDATED 12Z...
BACK EDGE OF CLIPPER CONTINUES TO SLIDE EAST ACROSS THE NORTHERN
IL/NORTHWEST IN AIRFIELDS. REGIONAL RADAR DEPICTION INDICATES THE
BACK EDGE OF THE PRECIP WILL BE NEARING ORD/MDW BETWEEN 12-13Z.
CIGS WILL THEN LINGER ARND LOW END MVFR...POSSIBLY DIP TO IFR MID-
MORNING THRU EARLY AFTN. WINDS REMAIN SOUTHERLY WITH OCCASIONAL
GUSTS TO 15-19KT...SOME DRY AIR EVENTUALLY WORKS BACK INTO THE
AREA MIDDAY AND ALLOWS CIGS TO LIFT SLIGHTLY BUT REMAIN MVFR.
THEN YET ANOTHER CLIPPER IS POISED TO ARRIVE AFT 22Z...WITH LIGHT
SNOW DEVELOPING ARND 00-03Z THUR.
WINDS THEN VEER TO WEST ARND 10-12KT THRU DAYBREAK THUR.
BEACHLER
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* HIGH CONFIDENCE IN CIGS REMAINING AT OR BELOW 1500 FT THROUGH
EARLY AFTERNOON. LOW CONFIDENCE ON WHETHER IFR WILL BE REACHED.
* HIGH CONFIDENCE IN WIND DIR/SPEED/GUSTS.
* LOW/MEDIUM CONFIDENCE IN LGT SNOW DEVELOPING AFT 22Z.
BEACHLER/MTF
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT...MAINLY VFR. POSSIBLE PATCHY MVFR CIGS.
THU THROUGH MON...VFR. SLT CHC -SN ON SUN AS WELL AS MON NIGHT.
TUESDAY...SLT CHC -SN.
BEACHLER
&&
.MARINE...
302 AM CST
HAZARDOUS WAVES/WINDS WILL FOR THE NEARSHORE WATERS AND MAY ALSO
SEE OCCASIONAL GALE FORCE GUSTS IN THE NEARSHORE WATERS THRU
MIDDAY.
SFC RIDGE CENTERED OVER THE OHIO VALLEY CONTINUES TO DRIFT EAST
TOWARDS THE MIDDLE ATLANTIC REGION...STRETCHING NORTH TO QUEBEC.
MEANWHILE A TROUGH OF LOW PRESSURE OVER THE UPPER MIDWEST WILL
SLIDE NORTHEAST TOWARDS CENTRAL ONTARIO THIS MORNING...THEN SLOWLY
LIFT NORTHEAST ACROSS JAMES BAY BY EARLY THURSDAY MORNING. THE
GRADIENT THAT WAS EXPECTED TO DEVELOP AND PRODUCE THE GALES
DEVELOPED BUT REMAINED WELL NORTH OF THE LAKE ACROSS LAKE
SUPERIOR...HOWEVER SOME REPORTS ACROSS THE FAR NORTHERN PORTION OF
LAKE MICHIGAN INDICATE LOW END GALES. SO GIVEN THE REDUCED
CONFIDENCE IN THE GALES AND LACK OF OBSERVATIONS TO SUPPORT
KEEPING THE GALE WARNING GOING...HAVE OPTED TO CANCEL THE GALE
WARNING EARLY. WILL HOWEVER CONTINUE TO MENTION OCCASIONAL GALE
FORCE GUSTS TO 35 KT THROUGH MID MORNING...THEN THE GRADIENT WILL
CONTINUE TO WEAKEN. WINDS WILL STEADILY SHIFT FROM SOUTHWEST TO
WEST BY LATE THIS AFTERNOON...THEN CONTINUE TO DIMINISH TO AROUND
15 TO 25 KT. HAZARDOUS WINDS AND WAVES WILL PERSIST FOR THE
NEARSHORE WATERS AND CONFIDENCE REMAINS HIGH THAT THE SMALL CRAFT
ADVISORY WILL CONTINUE. IT IS POSSIBLE THAT THE SMALL CRAFT
ADVISORY WILL NEED TO BE EXTENDED FOR THE INDIANA NEARSHORE WATERS
AS WINDS TURN WEST...THIS MAY HELP KEEP ELEVATED WAVES LONGER FOR
THIS FAR SOUTHEAST CORNER OF LAKE MICHIGAN.
THE NEXT WEATHER SYSTEM TO BRING A STRONG GRADIENT TO THE LAKE
WILL ARRIVE SAT...AND LIKELY PRODUCE WINDS TO 30KT. IT IS POSSIBLE
A FEW GUSTS TO GALE FORCE MAY OCCUR SAT.
THEN ANOTHER STRONG RIDGE OF HIGH PRESSURE WILL SLIDE SOUTH FROM
CENTRAL CANADA FOR THE SECOND HALF OF THE WEEKEND AND MAY BRING A
TIGHT GRADIENT TO THE LAKE.
SFC RIDGE OVER THE OHIO VALLEY WILL CONTINUE TO DRIFT EAST
TONIGHT...WITH A TIGHTENING GRADIENT ALONG THE WESTERN EDGE. THIS
TIGHT GRADIENT WILL SLIDE OVER THE LAKE TONIGHT...PRODUCING
SOUTH/SOUTHWEST GALES BETWEEN 35-40KT OVERNIGHT. THE GRADIENT
CONTINUES TO SLIDE EAST WITH THE ARRIVAL OF A CLIPPER LOW
PRESSURE. THIS CLIPPER WILL ALLOW THE WINDS TO BECOME
WESTERLY...AND SHOULD SEE GALES COME TO AN END BY MID-MORNING WED.
HOWEVER THE GRADIENT WILL REMAIN RELATIVELY STRONG AND PRODUCE
WINDS TO 30KT THRU MIDDAY WED BEFORE DIMINISHING TO 15 TO 25 KT BY
WED NIGHT.
THE NEXT WEATHER SYSTEM TO BRING A STRONG GRADIENT TO THE LAKE
WILL ARRIVE SAT...AND LIKELY PRODUCE WINDS TO 30KT. IT IS POSSIBLE
A FEW GUSTS TO GALE FORCE MAY OCCUR SAT.
THEN ANOTHER STRONG RIDGE OF HIGH PRESSURE WILL SLIDE SOUTH FROM
CENTRAL CANADA FOR THE SECOND HALF OF THE WEEKEND AND MAY BRING A
TIGHT GRADIENT TO THE LAKE.
BEACHLER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 10 PM WEDNESDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion
National Weather Service Lincoln IL
556 AM CST Wed Dec 25 2013
.DISCUSSION...
ISSUED 209 AM CST Wed Dec 25 2013
No major storm systems are anticipated across central Illinois
over the next week, as a prevailing northwesterly flow pattern
brings periodic flurries/very light snow and bouts of very cold
air.
SHORT TERM...Today through Friday
First weak system embedded within the northwesterly flow is
currently approaching the Mississippi River as an elongated
vorticity max stretching from Wisconsin to the Texas panhandle.
This feature has been shearing/weakening as it tracks eastward,
and with limited moisture to work with, has produced only very
meager amounts of light snow across parts of central and northern
Iowa. Stronger lift and steadier snows have been confined further
north across Minnesota into Wisconsin. Despite models insisting on
precip development further south, have not seen much evidence
upstream over Missouri, so have decided to downplay the snow
chances this morning. Will maintain low chance POPs along/north of
the I-74 corridor through midday, where a dusting is possible.
Further south, will only mention scattered flurries across the
remainder of the KILX CWA.
Once the initial wave passes, another disturbance currently
dropping into North Dakota will skirt across northern Illinois
this evening. Due to increasing synoptic lift ahead of this
feature, have added flurries to the forecast along/west of the
Illinois River late this afternoon, then everywhere tonight.
Upper pattern will begin to go zonal by the end of the week,
signaling a brief warming trend that will help boost highs well
into the 30s and even the lower 40s south of I-70 by Friday.
LONG TERM...Saturday through Tuesday
Warmest day of the forecast period will be Saturday, as
southwesterly winds ahead of an approaching Arctic cold front
allow temps to reach the 40s across the board. Models have been
consistent in bringing the cold front through central Illinois on
Sunday, with each run suggesting clouds and perhaps a few
snow-showers. Will carry low chance POPs for snow on Sunday
accordingly. Once front passes, another chunk of very cold air
will arrive early next week as the upper flow pattern returns to
northwesterly. With 850mb temps progged to fall into the -12 to
-14C range, highs will drop back into the teens and lower 20s by
Monday. After that, will have to watch the next approaching
clipper system for late Monday into Tuesday. Latest models are
slower and a bit further north with this system, but still suggest
a period of light snow will be possible across the northern CWA
late Tuesday. Timing of these features this far out is quite
difficult, so will only mention very low chance POPs across the
north at this time.
Barnes
&&
.AVIATION...
ISSUED 556 AM CST Wed Dec 25 2013
MVFR clouds will prevail for the first few hours of this TAF
period as a fast moving clipper produces light snow for a period
of an hour or so. Snow has already ended at PIA, and is just
affecting SPI. Over the next 2 hours, BMI, DEC and CMI will see
the snow move through. IFR clouds are poised to develop 2 hours
after the snow ends, based on observation trends upstream. The NAM
and RAP soundings show IFR conditions could persist into the
afternoon, and possibly until near sunset. MVFR conditions could
develop as mixing increases this afternoon, but we generally held
off the return to MVFR clouds until 22-23z.
Some clearing should develop from west to east this evening, as
the drier air returns to lower levels. Clearing could reach PIA as
early as 01z and progress to CMI by 07z.
Winds will be primarily southwest until this evening when they
shift to the west and increase from around 10-12kt to 14-16kt.
Shimon
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1044 AM EST WED DEC 25 2013
.UPDATE...
ISSUED AT 1043 AM EST WED DEC 25 2013
CANX GOING WARNING FOR LUCE COUNTY EARLY GIVEN EXIT OF ENHANCED CLD
SHOWN ON IR STLT LOOP AND SHIFT OF HEAVY LES BAND TO THE E INTO
CHIPPEWA COUNTY PER CNDN MONTREAL RIVER RADAR. NEARBY SFC OBS ALSO
SHOW A WSHFT TO THE WSW AT ERY AND NAUBINWAY...CONSISTENT WITH THE
PASSAGE OF THE HEAVIER BAND TO THE E. SOME SCT SHSN WL CONT THRU THE
DAY IN LUCE COUNTY...BUT ANY ADDITIONAL ACCUM SHOULD BE LESS THAN AN
INCH.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 531 AM EST WED DEC 25 2013
PARADE OF SHORTWAVES IN STORE ACROSS UPPER GREAT LAKES FOR NEXT 24
HOURS AS UPR LAKES REMAINS ON PERIFERY OF MEAN TROUGH. LEAD
SHORTWAVE AND MOISTURE ADVECTION HAS RESULTED IN WIDESPREAD SNOW
WEST TO EAST ACROSS UPR MICHIGAN. LIMITED REPORTS BUT SEEMS MOST
SNOW /2-3 INCHES/ OCCURRED IN SCNTRL CWA ON NORTHERN FRINGE OF
BETTER DEEP LAYER Q-VECTOR CONVERGENCE.
OTHER AREA OF HIGHER SNOWFALL IS DUE TO LAKE ENHANCEMENT OFF LK
MICHIGAN OVER FAR EAST CWA...JUST TO EAST OF MANISTIQUE TOWARD
NEWBERRY. MQT AND APX RADARS SHOWED MAIN BAND OF LAKE EFFECT AS
EARLY AS 06Z WITH ECHOES OVER NORTHERN LK MICHIGAN UP TO 10KFT
SUGGESTING HEALTHY BAND OF SNOW. HAVING TO DO A LOT OF INTERPOLATION
AND EXTRAPOLATION IN DETERMINING WHAT IS GOING ON IN THSES AREAS
USING MDOT WEBCAMS AND FREQUENT CALLS TO THE ISQ AND ERY AWOS
/LONG-LINE TRANSMISSION OF MANY AWOS ACROSS THE REGION IS DOWN RIGHT
NOW/. WILL HAVE TO WAIT TO GET REPORTS LATER THIS MORNING...BUT AS
BEST WE CAN TELL SEEMS THE HEAVIEST AND MOST PERSISTENT SNOW HAS
OCCURRED FROM NEAR BLANEY PARK TOWARD MCMILLAN IN SOUTHWEST LUCE
COUNTY. JUST WITHIN LAST HOUR...HEAVY SNOW IS PUSHING TOWARD
NEWBERRY. GEM-REGIONAL AND HRRR PEGGING THINGS PRETTY WELL. BOTH
SHOW THE MAIN CONVERGENCE BAND AND HEAVY SNOW MOVING STEADILY TO
THE EAST THIS MORNING...PROBABLY OUT OF ERY BY 15Z IF NOT SOONER.
LOWERED SNOW AMOUNTS SLIGHTLY OVER SOUTHERN LUCE...BUT OVERALL WILL
KEEP HEADLINES AS IS FOR NOW AS WINDS ALONG LK MICHIGAN SHOWING
GUSTS OVER 30 MPH /PROBABLY REPRESENTATIVE WHAT IS OCCURRING WITHIN
THE SNOW BAND FARTHER INLAND/ WHICH WOULD BE RESULTING IN BLOWING
AND DRIFTING OF THE SNOW. WILL RE-EVALUATE THE HEADLINES TOWARD
DAYBREAK TO SEE IF SOME CHANGES ARE NEEDED.
ELSEWHERE...EXPECT THE WIDESPREAD SNOW TO TAPER OFF BY DAYBREAK.
GUSTY WINDS COULD EASILY BLOW THE FLUFFY SNOW AROUND SO PUT OUT
AN SPS MAINLY EMPHASIZING DIFFICULT TRAVEL IN SOME AREAS THIS
MORNING. LATER TODAY...ANOTHER SHORTWAVE CURRENTLY SLIDING ACROSS
MINNESOTA MAY RESULT IN A CONTINUATION OF SOME LGT SNOW OR FLURRIES
FOR MOST OF THE AREA.
INTO TONIGHT...EMPHASIS FOR LAKE EFFECT SHIFTS TO THE SNOWBELTS OF
WESTERN AND EVENTUALLY FAR NORTHEAST UPR MICHIGAN...MAINLY EAST OF
MUNISING AND TO THE NORTH OF NEWBERRY. LAST SHORTWAVE FAIRLY STRONG
BUT DIRECT IMPACTS MOSTLY STAY TO THE SOUTH OF UPR MICHIGAN AS WAVE
TRACKS FM CNTRL MN ACROSS WI. WAVE MAY ACT TO HOLD TROUGHING IN
PLACE OVER SCNTRL LK SUPERIOR RESULTING IN MAINLY WSW WINDS OVER
MUCH OF THE LAND AREAS AND NW WINDS OVER LK SUPERIOR. FOR THIS
REASON...LEANED TOWARD NCEP WRF-ARW/NMM IDEA OF CONVERGENCE BAND
TRYING TO GET GOING OVER THE KEWEENAW TOWARD EASTERN ALGER COUNTY
AFTER LATE EVENING. SOUNDINGS FOR TONIGHT SHOW DRYING AND SUBSIDENCE
ABOVE H8 BUT BULK OF LAKE EFFECT CONVECTIVE LAYER IS WELL WITHIN THE
DGZ RESULTING IN SLR/S SOLIDLY OVER 20:1 AND MAYBE PUSHING TOWARD
30:1. IF CONVERGENCE IS STRONGER...MAY SEE ADVY LEVEL SNOW AMOUNTS
FOR PORTIONS OF KEWEENAW AND PERHAPS AS FAR SOUTH AS HIGHER TERRAIN
OF NORTHERN ONTONAGON COUNTY...INCLUDING WHITE PINE AND ROCKLAND.
SINCE IT WILL BE VERY FLUFFY SNOW AND WINDS/BLSN WILL NOT BE TOO
MUCH OF A FACTOR AND SINCE SOME PLACES IN KEWEENAW ARE WELL OVER 100
INCHES ALREADY FOR SEASON...EVENT DOES NOT APPEAR TO SUPPORT THE
NEED FOR ADVY AS IT STANDS NOW. DAYSHIFT CAN RE-EVALUATE BUT DID NOT
ISSUE AT THIS TIME. HEAVIER LAKE EFFECT WILL ALSO AFFECT THE
SNOWBELTS OF THE NORTHEAST CWA WITH MOST SNOW NOT OCCURRING UNTIL
WELL AFTER MIDNIGHT ONCE WINDS SHIFT MORE WNW. INLAND FROM THE LAKE
EFFECT ISSUES...SKIES MAY TRY TO CLEAR OUT IF THE WINDS ARE MORE WSW
THAN WNW. IF THIS OCCURS...TEMPS OVER INLAND WEST AND CNTRL AND
MAYBE EVEN EASTERN CWA COULD FALL WELL BELOW ZERO.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 531 AM EST WED DEC 25 2013
WARMING WILL OCCUR LATE THIS WEEK AS FLOW BRIEFLY BECOMES ZONAL
ACROSS THE NRN CONUS. HOWEVER...OVER THE NEXT 7 DAYS...THE CURRENT
RATHER DISORGANIZED POLAR VORTEX LOCATED WELL N IN NRN CANADA
WILL REORGANIZE/EXPAND AND DROP S TO THE VCNTY OF HUDSON BAY. AS A
RESULT...ARCTIC AIR WILL AGAIN SPREAD S INTO THE UPPER GREAT LAKES
NEXT WEEK...AND THERE MAY BE A COUPLE OF SHOTS OF BITTER COLD AIR.
PATTERN DOES NOT LOOK FAVORABLE FOR MUCH IN THE WAY OF WIDESPREAD
SYNOPTIC SNOWFALL OVER THE NEXT 7 DAYS. NEXT WEEK...LES WILL BE THE
MAIN PCPN CONCERN...MOSTLY FOR SNOWBELTS FAVORED BY W TO NW WINDS.
BEGINNING THU...WNW FLOW LES WILL GRADUALLY DIMINISH AS WEAK SFC
HIGH PRES RIDGE MOVES FROM THE UPPER MISSISSIPPI VALLEY TOWARD THE
UPPER LAKES. DGZ OCCUPIES A GOOD PORTION OF THE CONVECTIVE LAYER...
SO MIGHT BE ABLE TO FLUFF UP SEVERAL INCHES OF SNOW ACCUMULATION
THU. BEST ACCUMULATIONS SHOULD OCCUR IN FAR NRN ONTONAGON/CNTRL
HOUGHTON COUNTIES DUE TO CONVERGENT WRLY FLOW INTO THAT AREA AND
ALSO ERN ALGER/NRN LUCE COUNTIES WHERE MODELS DEPICT RATHER STRONG
LOW-LEVEL CONVERGENCE. ADVY TYPE HEADLINE MAY BE REQUIRED FOR THE
LATTER AREA.
WITH PASSAGE OF SFC HIGH PRES RIDGE THU NIGHT...LINGERING LES WILL
END AS WINDS SHIFT SW/OFFSHORE. FAVORED THE LOWER SIDE OF GUIDANCE
FOR MIN TEMPS WITH AT LEAST A PERIOD OF LIGHT WINDS AND PARTLY
CLOUDY SKIES IN MOST AREAS.
WAA PATTERN WILL BE IN FULL SWING FRI AS PACIFIC AIR SPREADS OUT
ACROSS THE NRN PLAINS IN DEVELOPING ZONAL FLOW. MIGHT BE A LITTLE
PCPN ACROSS NRN UPPER MI...BUT BETTER PCPN POTENTIAL WILL BE FARTHER
N WHERE SUFFICIENT LOW-LEVEL MOISTENING IS MORE LIKELY. TEMPS WILL
REACH THE 20S ACROSS THE BOARD.
WARMING WILL CONTINUE SAT AHEAD OF A SHORTWAVE TRACKING FROM
BC/PACIFIC NW TO THE NRN PLAINS. MOST LOCATIONS SHOULD TOP OUT
AROUND 30F. HOWEVER...A COLD FRONT DRIFTING S ACROSS UPPER MI WILL
INFLUENCE MAX TEMPS DEPENDING ON ITS TIMING. UPPER DIVERGENCE
ASSOCIATED WITH RIGHT ENTRANCE OF UPPER JET TO THE N AND NE SHOULD
SUPPORT A RIBBON OF -SN BEHIND THE SOUTHWARD DRIFTING COLD FRONT.
THAT -SN SHOULD BEGIN TO AFFECT NW UPPER MI SAT AFTN. AS COLD FRONT
CONTINUES TO DROP S SAT NIGHT/SUN MORNING...EXPECT MOST OF THE FCST
AREA TO SEE SOME -SN...AIDED BY RIGHT ENTRANCE UPPER DIVERGENCE.
SOME LAKE ENHANCEMENT SEEMS LIKELY FOR MOST IF NOT ALL OF NRN UPPER
MI AS WINDS WILL LIKELY SHIFT N FOR A TIME BEHIND COLD FRONT AND
POTENTIAL WEAK SFC WAVE THAT WILL ALSO BE TRACKING ALONG FRONT.
BEHIND THE COLD FRONT AND WITH THE PASSAGE OF ANOTHER SHORTWAVE
ROTATING THRU THE UPPER LAKES AROUND EXPANDING POLAR VORTEX...MUCH
COLDER AIR WILL DUMP INTO THE UPPER LAKES SAT NIGHT/SUN. THIS WILL
RESULT IN NW FLOW LES TAKING OVER SUN AS 850MB TEMPS PLUMMET INTO
THE LOW/MID -20S C. EXPECT SLOWLY FALLING TEMPS DURING THE DAY SUN.
PERSISTENT LES WILL THEN SET UP MON/TUE...MOSTLY FOR W TO WNW WIND
FAVORED SNOWBELTS...AS ACRTIC AIR SETTLES OVER THE AREA (850MB TEMPS
IN THE MID -20S C). LES WILL THEN CONTINUE THRU THE END OF NEXT WEEK
AS ARCTIC AIR WILL DOMINATE THE UPPER LAKES.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 646 AM EST WED DEC 25 2013
LGT SNOW AND FLURRIES CONTINUE INTO EARLY AFTN AS A LOW PRESSURE
TROUGH SLOWLY CROSSES THE AREA. EXPECT MVFR CONDITIONS WITH THE SNOW
BOTH FM CIGS AND VSBY. AS WINDS TURN TO THE NORTHWEST LATER TODAY
INTO TONIGHT IN WAKE OF THE LOW...LAKE EFFECT SNOW SHOWERS WITH IFR
CONDITIONS WILL DEVELOP AT IWD AND CMX. POTENTIAL FOR HEAVIER BAND
OF SNOW TO PRODUCE LIFR CONDITIONS AT CMX...BUT NOT ENOUGH CONFIDENCE
ON EXACT LOCATION TO INCLUDE AT THIS TIME. SOME MORE LGT SNOW OR
FLURRIES MAY OCCUR TONIGHT AT SAW AS AN UPPER DISTURBANCE MOVES JUST
SOUTH OF THE AREA...THOUGH AFTER THIS SYSTEM MOVES BY CLOUDS MAY TRY
TO SCATTER OUT LATE TONIGHT.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 531 AM EST WED DEC 25 2013
GALES EARLY TODAY FOR EASTERN PORTIONS OF LK SUPERIOR AS SOUTH
WINDS ARE ENHANCED BY PRESSURE FALLS TO NORTH OF LK SUPERIOR. EXPECT
WINDS TO DIMINISH TO LESS THAN 25 KTS LATER AFTN THROUGH TONIGHT.
WINDS WILL DIMINISH FURTHER TO 10-20KT ACROSS MOST OF LAKE SUPERIOR
THU/THU NIGHT AS A WEAK SFC HIGH PRES RIDGE PASSES. SW WINDS WILL
THEN INCREASE TO 15-25KT FRI AHEAD OF THE NEXT APPROACHING COLD
FRONT. AS THE FRONT DRIFTS S ACROSS THE AREA...WINDS WILL DIMINISH
FRI NIGHT/SAT MORNING. ARCTIC AIR WILL THEN SURGE INTO THE UPPER
LAKES LATE SAT THRU EARLY NEXT WEEK. MAY SEE SOME PERIODS OF GALES
EARLY NEXT WEEK ALONG WITH THE RETURN OF HVY FREEZING SPRAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...KC
SHORT TERM...JLA
LONG TERM...ROLFSON
AVIATION...JLA
MARINE...JLA/ROLFSON
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
648 AM EST WED DEC 25 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 531 AM EST WED DEC 25 2013
PARADE OF SHORTWAVES IN STORE ACROSS UPPER GREAT LAKES FOR NEXT 24
HOURS AS UPR LAKES REMAINS ON PERIFERY OF MEAN TROUGH. LEAD
SHORTWAVE AND MOISTURE ADVECTION HAS RESULTED IN WIDESPREAD SNOW
WEST TO EAST ACROSS UPR MICHIGAN. LIMITED REPORTS BUT SEEMS MOST
SNOW /2-3 INCHES/ OCCURRED IN SCNTRL CWA ON NORTHERN FRINGE OF
BETTER DEEP LAYER Q-VECTOR CONVERGENCE.
OTHER AREA OF HIGHER SNOWFALL IS DUE TO LAKE ENHANCEMENT OFF LK
MICHIGAN OVER FAR EAST CWA...JUST TO EAST OF MANISTIQUE TOWARD
NEWBERRY. MQT AND APX RADARS SHOWED MAIN BAND OF LAKE EFFECT AS
EARLY AS 06Z WITH ECHOES OVER NORTHERN LK MICHIGAN UP TO 10KFT
SUGGESTING HEALTHY BAND OF SNOW. HAVING TO DO A LOT OF INTERPOLATION
AND EXTRAPOLATION IN DETERMINING WHAT IS GOING ON IN THSES AREAS
USING MDOT WEBCAMS AND FREQUENT CALLS TO THE ISQ AND ERY AWOS
/LONG-LINE TRANSMISSION OF MANY AWOS ACROSS THE REGION IS DOWN RIGHT
NOW/. WILL HAVE TO WAIT TO GET REPORTS LATER THIS MORNING...BUT AS
BEST WE CAN TELL SEEMS THE HEAVIEST AND MOST PERSISTENT SNOW HAS
OCCURRED FROM NEAR BLANEY PARK TOWARD MCMILLAN IN SOUTHWEST LUCE
COUNTY. JUST WITHIN LAST HOUR...HEAVY SNOW IS PUSHING TOWARD
NEWBERRY. GEM-REGIONAL AND HRRR PEGGING THINGS PRETTY WELL. BOTH
SHOW THE MAIN CONVERGENCE BAND AND HEAVY SNOW MOVING STEADILY TO
THE EAST THIS MORNING...PROBABLY OUT OF ERY BY 15Z IF NOT SOONER.
LOWERED SNOW AMOUNTS SLIGHTLY OVER SOUTHERN LUCE...BUT OVERALL WILL
KEEP HEADLINES AS IS FOR NOW AS WINDS ALONG LK MICHIGAN SHOWING
GUSTS OVER 30 MPH /PROBABLY REPRESENTATIVE WHAT IS OCCURRING WITHIN
THE SNOW BAND FARTHER INLAND/ WHICH WOULD BE RESULTING IN BLOWING
AND DRIFTING OF THE SNOW. WILL RE-EVALUATE THE HEADLINES TOWARD
DAYBREAK TO SEE IF SOME CHANGES ARE NEEDED.
ELSEWHERE...EXPECT THE WIDESPREAD SNOW TO TAPER OFF BY DAYBREAK.
GUSTY WINDS COULD EASILY BLOW THE FLUFFY SNOW AROUND SO PUT OUT
AN SPS MAINLY EMPHASIZING DIFFICULT TRAVEL IN SOME AREAS THIS
MORNING. LATER TODAY...ANOTHER SHORTWAVE CURRENTLY SLIDING ACROSS
MINNESOTA MAY RESULT IN A CONTINUATION OF SOME LGT SNOW OR FLURRIES
FOR MOST OF THE AREA.
INTO TONIGHT...EMPHASIS FOR LAKE EFFECT SHIFTS TO THE SNOWBELTS OF
WESTERN AND EVENTUALLY FAR NORTHEAST UPR MICHIGAN...MAINLY EAST OF
MUNISING AND TO THE NORTH OF NEWBERRY. LAST SHORTWAVE FAIRLY STRONG
BUT DIRECT IMPACTS MOSTLY STAY TO THE SOUTH OF UPR MICHIGAN AS WAVE
TRACKS FM CNTRL MN ACROSS WI. WAVE MAY ACT TO HOLD TROUGHING IN
PLACE OVER SCNTRL LK SUPERIOR RESULTING IN MAINLY WSW WINDS OVER
MUCH OF THE LAND AREAS AND NW WINDS OVER LK SUPERIOR. FOR THIS
REASON...LEANED TOWARD NCEP WRF-ARW/NMM IDEA OF CONVERGENCE BAND
TRYING TO GET GOING OVER THE KEWEENAW TOWARD EASTERN ALGER COUNTY
AFTER LATE EVENING. SOUNDINGS FOR TONIGHT SHOW DRYING AND SUBSIDENCE
ABOVE H8 BUT BULK OF LAKE EFFECT CONVECTIVE LAYER IS WELL WITHIN THE
DGZ RESULTING IN SLR/S SOLIDLY OVER 20:1 AND MAYBE PUSHING TOWARD
30:1. IF CONVERGENCE IS STRONGER...MAY SEE ADVY LEVEL SNOW AMOUNTS
FOR PORTIONS OF KEWEENAW AND PERHAPS AS FAR SOUTH AS HIGHER TERRAIN
OF NORTHERN ONTONAGON COUNTY...INCLUDING WHITE PINE AND ROCKLAND.
SINCE IT WILL BE VERY FLUFFY SNOW AND WINDS/BLSN WILL NOT BE TOO
MUCH OF A FACTOR AND SINCE SOME PLACES IN KEWEENAW ARE WELL OVER 100
INCHES ALREADY FOR SEASON...EVENT DOES NOT APPEAR TO SUPPORT THE
NEED FOR ADVY AS IT STANDS NOW. DAYSHIFT CAN RE-EVALUATE BUT DID NOT
ISSUE AT THIS TIME. HEAVIER LAKE EFFECT WILL ALSO AFFECT THE
SNOWBELTS OF THE NORTHEAST CWA WITH MOST SNOW NOT OCCURRING UNTIL
WELL AFTER MIDNIGHT ONCE WINDS SHIFT MORE WNW. INLAND FROM THE LAKE
EFFECT ISSUES...SKIES MAY TRY TO CLEAR OUT IF THE WINDS ARE MORE WSW
THAN WNW. IF THIS OCCURS...TEMPS OVER INLAND WEST AND CNTRL AND
MAYBE EVEN EASTERN CWA COULD FALL WELL BELOW ZERO.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 531 AM EST WED DEC 25 2013
WARMING WILL OCCUR LATE THIS WEEK AS FLOW BRIEFLY BECOMES ZONAL
ACROSS THE NRN CONUS. HOWEVER...OVER THE NEXT 7 DAYS...THE CURRENT
RATHER DISORGANIZED POLAR VORTEX LOCATED WELL N IN NRN CANADA
WILL REORGANIZE/EXPAND AND DROP S TO THE VCNTY OF HUDSON BAY. AS A
RESULT...ARCTIC AIR WILL AGAIN SPREAD S INTO THE UPPER GREAT LAKES
NEXT WEEK...AND THERE MAY BE A COUPLE OF SHOTS OF BITTER COLD AIR.
PATTERN DOES NOT LOOK FAVORABLE FOR MUCH IN THE WAY OF WIDESPREAD
SYNOPTIC SNOWFALL OVER THE NEXT 7 DAYS. NEXT WEEK...LES WILL BE THE
MAIN PCPN CONCERN...MOSTLY FOR SNOWBELTS FAVORED BY W TO NW WINDS.
BEGINNING THU...WNW FLOW LES WILL GRADUALLY DIMINISH AS WEAK SFC
HIGH PRES RIDGE MOVES FROM THE UPPER MISSISSIPPI VALLEY TOWARD THE
UPPER LAKES. DGZ OCCUPIES A GOOD PORTION OF THE CONVECTIVE LAYER...
SO MIGHT BE ABLE TO FLUFF UP SEVERAL INCHES OF SNOW ACCUMULATION
THU. BEST ACCUMULATIONS SHOULD OCCUR IN FAR NRN ONTONAGON/CNTRL
HOUGHTON COUNTIES DUE TO CONVERGENT WRLY FLOW INTO THAT AREA AND
ALSO ERN ALGER/NRN LUCE COUNTIES WHERE MODELS DEPICT RATHER STRONG
LOW-LEVEL CONVERGENCE. ADVY TYPE HEADLINE MAY BE REQUIRED FOR THE
LATTER AREA.
WITH PASSAGE OF SFC HIGH PRES RIDGE THU NIGHT...LINGERING LES WILL
END AS WINDS SHIFT SW/OFFSHORE. FAVORED THE LOWER SIDE OF GUIDANCE
FOR MIN TEMPS WITH AT LEAST A PERIOD OF LIGHT WINDS AND PARTLY
CLOUDY SKIES IN MOST AREAS.
WAA PATTERN WILL BE IN FULL SWING FRI AS PACIFIC AIR SPREADS OUT
ACROSS THE NRN PLAINS IN DEVELOPING ZONAL FLOW. MIGHT BE A LITTLE
PCPN ACROSS NRN UPPER MI...BUT BETTER PCPN POTENTIAL WILL BE FARTHER
N WHERE SUFFICIENT LOW-LEVEL MOISTENING IS MORE LIKELY. TEMPS WILL
REACH THE 20S ACROSS THE BOARD.
WARMING WILL CONTINUE SAT AHEAD OF A SHORTWAVE TRACKING FROM
BC/PACIFIC NW TO THE NRN PLAINS. MOST LOCATIONS SHOULD TOP OUT
AROUND 30F. HOWEVER...A COLD FRONT DRIFTING S ACROSS UPPER MI WILL
INFLUENCE MAX TEMPS DEPENDING ON ITS TIMING. UPPER DIVERGENCE
ASSOCIATED WITH RIGHT ENTRANCE OF UPPER JET TO THE N AND NE SHOULD
SUPPORT A RIBBON OF -SN BEHIND THE SOUTHWARD DRIFTING COLD FRONT.
THAT -SN SHOULD BEGIN TO AFFECT NW UPPER MI SAT AFTN. AS COLD FRONT
CONTINUES TO DROP S SAT NIGHT/SUN MORNING...EXPECT MOST OF THE FCST
AREA TO SEE SOME -SN...AIDED BY RIGHT ENTRANCE UPPER DIVERGENCE.
SOME LAKE ENHANCEMENT SEEMS LIKELY FOR MOST IF NOT ALL OF NRN UPPER
MI AS WINDS WILL LIKELY SHIFT N FOR A TIME BEHIND COLD FRONT AND
POTENTIAL WEAK SFC WAVE THAT WILL ALSO BE TRACKING ALONG FRONT.
BEHIND THE COLD FRONT AND WITH THE PASSAGE OF ANOTHER SHORTWAVE
ROTATING THRU THE UPPER LAKES AROUND EXPANDING POLAR VORTEX...MUCH
COLDER AIR WILL DUMP INTO THE UPPER LAKES SAT NIGHT/SUN. THIS WILL
RESULT IN NW FLOW LES TAKING OVER SUN AS 850MB TEMPS PLUMMET INTO
THE LOW/MID -20S C. EXPECT SLOWLY FALLING TEMPS DURING THE DAY SUN.
PERSISTENT LES WILL THEN SET UP MON/TUE...MOSTLY FOR W TO WNW WIND
FAVORED SNOWBELTS...AS ACRTIC AIR SETTLES OVER THE AREA (850MB TEMPS
IN THE MID -20S C). LES WILL THEN CONTINUE THRU THE END OF NEXT WEEK
AS ARCTIC AIR WILL DOMINATE THE UPPER LAKES.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 646 AM EST WED DEC 25 2013
LGT SNOW AND FLURRIES CONTINUE INTO EARLY AFTN AS A LOW PRESSURE
TROUGH SLOWLY CROSSES THE AREA. EXPECT MVFR CONDITIONS WITH THE SNOW
BOTH FM CIGS AND VSBY. AS WINDS TURN TO THE NORTHWEST LATER TODAY
INTO TONIGHT IN WAKE OF THE LOW...LAKE EFFECT SNOW SHOWERS WITH IFR
CONDITIONS WILL DEVELOP AT IWD AND CMX. POTENTIAL FOR HEAVIER BAND
OF SNOW TO PRODUCE LIFR CONDITIONS AT CMX...BUT NOT ENOUGH CONFIDENCE
ON EXACT LOCATION TO INCLUDE AT THIS TIME. SOME MORE LGT SNOW OR
FLURRIES MAY OCCUR TONIGHT AT SAW AS AN UPPER DISTURBANCE MOVES JUST
SOUTH OF THE AREA...THOUGH AFTER THIS SYSTEM MOVES BY CLOUDS MAY TRY
TO SCATTER OUT LATE TONIGHT. &&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 531 AM EST WED DEC 25 2013
GALES EARLY TODAY FOR EASTERN PORTIONS OF LK SUPERIOR AS SOUTH
WINDS ARE ENHANCED BY PRESSURE FALLS TO NORTH OF LK SUPERIOR. EXPECT
WINDS TO DIMINISH TO LESS THAN 25 KTS LATER AFTN THROUGH TONIGHT.
WINDS WILL DIMINISH FURTHER TO 10-20KT ACROSS MOST OF LAKE SUPERIOR
THU/THU NIGHT AS A WEAK SFC HIGH PRES RIDGE PASSES. SW WINDS WILL
THEN INCREASE TO 15-25KT FRI AHEAD OF THE NEXT APPROACHING COLD
FRONT. AS THE FRONT DRIFTS S ACROSS THE AREA...WINDS WILL DIMINISH
FRI NIGHT/SAT MORNING. ARCTIC AIR WILL THEN SURGE INTO THE UPPER
LAKES LATE SAT THRU EARLY NEXT WEEK. MAY SEE SOME PERIODS OF GALES
EARLY NEXT WEEK ALONG WITH THE RETURN OF HVY FREEZING SPRAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR MIZ014-
085.
WINTER STORM WARNING UNTIL 1 PM EST THIS AFTERNOON FOR MIZ007.
LAKE SUPERIOR...
GALE WARNING UNTIL 7 AM EST THIS MORNING FOR LSZ266.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLA
LONG TERM...ROLFSON
AVIATION...JLA
MARINE...JLA/ROLFSON
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
533 AM EST WED DEC 25 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 531 AM EST WED DEC 25 2013
PARADE OF SHORTWAVES IN STORE ACROSS UPPER GREAT LAKES FOR NEXT 24
HOURS AS UPR LAKES REMAINS ON PERIFERY OF MEAN TROUGH. LEAD
SHORTWAVE AND MOISTURE ADVECTION HAS RESULTED IN WIDESPREAD SNOW
WEST TO EAST ACROSS UPR MICHIGAN. LIMITED REPORTS BUT SEEMS MOST
SNOW /2-3 INCHES/ OCCURRED IN SCNTRL CWA ON NORTHERN FRINGE OF
BETTER DEEP LAYER Q-VECTOR CONVERGENCE.
OTHER AREA OF HIGHER SNOWFALL IS DUE TO LAKE ENHANCEMENT OFF LK
MICHIGAN OVER FAR EAST CWA...JUST TO EAST OF MANISTIQUE TOWARD
NEWBERRY. MQT AND APX RADARS SHOWED MAIN BAND OF LAKE EFFECT AS
EARLY AS 06Z WITH ECHOES OVER NORTHERN LK MICHIGAN UP TO 10KFT
SUGGESTING HEALTHY BAND OF SNOW. HAVING TO DO A LOT OF INTERPOLATION
AND EXTRAPOLATION IN DETERMINING WHAT IS GOING ON IN THSES AREAS
USING MDOT WEBCAMS AND FREQUENT CALLS TO THE ISQ AND ERY AWOS
/LONG-LINE TRANSMISSION OF MANY AWOS ACROSS THE REGION IS DOWN RIGHT
NOW/. WILL HAVE TO WAIT TO GET REPORTS LATER THIS MORNING...BUT AS
BEST WE CAN TELL SEEMS THE HEAVIEST AND MOST PERSISTENT SNOW HAS
OCCURRED FROM NEAR BLANEY PARK TOWARD MCMILLAN IN SOUTHWEST LUCE
COUNTY. JUST WITHIN LAST HOUR...HEAVY SNOW IS PUSHING TOWARD
NEWBERRY. GEM-REGIONAL AND HRRR PEGGING THINGS PRETTY WELL. BOTH
SHOW THE MAIN CONVERGENCE BAND AND HEAVY SNOW MOVING STEADILY TO
THE EAST THIS MORNING...PROBABLY OUT OF ERY BY 15Z IF NOT SOONER.
LOWERED SNOW AMOUNTS SLIGHTLY OVER SOUTHERN LUCE...BUT OVERALL WILL
KEEP HEADLINES AS IS FOR NOW AS WINDS ALONG LK MICHIGAN SHOWING
GUSTS OVER 30 MPH /PROBABLY REPRESENTATIVE WHAT IS OCCURRING WITHIN
THE SNOW BAND FARTHER INLAND/ WHICH WOULD BE RESULTING IN BLOWING
AND DRIFTING OF THE SNOW. WILL RE-EVALUATE THE HEADLINES TOWARD
DAYBREAK TO SEE IF SOME CHANGES ARE NEEDED.
ELSEWHERE...EXPECT THE WIDESPREAD SNOW TO TAPER OFF BY DAYBREAK.
GUSTY WINDS COULD EASILY BLOW THE FLUFFY SNOW AROUND SO PUT OUT
AN SPS MAINLY EMPHASIZING DIFFICULT TRAVEL IN SOME AREAS THIS
MORNING. LATER TODAY...ANOTHER SHORTWAVE CURRENTLY SLIDING ACROSS
MINNESOTA MAY RESULT IN A CONTINUATION OF SOME LGT SNOW OR FLURRIES
FOR MOST OF THE AREA.
INTO TONIGHT...EMPHASIS FOR LAKE EFFECT SHIFTS TO THE SNOWBELTS OF
WESTERN AND EVENTUALLY FAR NORTHEAST UPR MICHIGAN...MAINLY EAST OF
MUNISING AND TO THE NORTH OF NEWBERRY. LAST SHORTWAVE FAIRLY STRONG
BUT DIRECT IMPACTS MOSTLY STAY TO THE SOUTH OF UPR MICHIGAN AS WAVE
TRACKS FM CNTRL MN ACROSS WI. WAVE MAY ACT TO HOLD TROUGHING IN
PLACE OVER SCNTRL LK SUPERIOR RESULTING IN MAINLY WSW WINDS OVER
MUCH OF THE LAND AREAS AND NW WINDS OVER LK SUPERIOR. FOR THIS
REASON...LEANED TOWARD NCEP WRF-ARW/NMM IDEA OF CONVERGENCE BAND
TRYING TO GET GOING OVER THE KEWEENAW TOWARD EASTERN ALGER COUNTY
AFTER LATE EVENING. SOUNDINGS FOR TONIGHT SHOW DRYING AND SUBSIDENCE
ABOVE H8 BUT BULK OF LAKE EFFECT CONVECTIVE LAYER IS WELL WITHIN THE
DGZ RESULTING IN SLR/S SOLIDLY OVER 20:1 AND MAYBE PUSHING TOWARD
30:1. IF CONVERGENCE IS STRONGER...MAY SEE ADVY LEVEL SNOW AMOUNTS
FOR PORTIONS OF KEWEENAW AND PERHAPS AS FAR SOUTH AS HIGHER TERRAIN
OF NORTHERN ONTONAGON COUNTY...INCLUDING WHITE PINE AND ROCKLAND.
SINCE IT WILL BE VERY FLUFFY SNOW AND WINDS/BLSN WILL NOT BE TOO
MUCH OF A FACTOR AND SINCE SOME PLACES IN KEWEENAW ARE WELL OVER 100
INCHES ALREADY FOR SEASON...EVENT DOES NOT APPEAR TO SUPPORT THE
NEED FOR ADVY AS IT STANDS NOW. DAYSHIFT CAN RE-EVALUATE BUT DID NOT
ISSUE AT THIS TIME. HEAVIER LAKE EFFECT WILL ALSO AFFECT THE
SNOWBELTS OF THE NORTHEAST CWA WITH MOST SNOW NOT OCCURRING UNTIL
WELL AFTER MIDNIGHT ONCE WINDS SHIFT MORE WNW. INLAND FROM THE LAKE
EFFECT ISSUES...SKIES MAY TRY TO CLEAR OUT IF THE WINDS ARE MORE WSW
THAN WNW. IF THIS OCCURS...TEMPS OVER INLAND WEST AND CNTRL AND
MAYBE EVEN EASTERN CWA COULD FALL WELL BELOW ZERO.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 531 AM EST WED DEC 25 2013
WARMING WILL OCCUR LATE THIS WEEK AS FLOW BRIEFLY BECOMES ZONAL
ACROSS THE NRN CONUS. HOWEVER...OVER THE NEXT 7 DAYS...THE CURRENT
RATHER DISORGANIZED POLAR VORTEX LOCATED WELL N IN NRN CANADA
WILL REORGANIZE/EXPAND AND DROP S TO THE VCNTY OF HUDSON BAY. AS A
RESULT...ARCTIC AIR WILL AGAIN SPREAD S INTO THE UPPER GREAT LAKES
NEXT WEEK...AND THERE MAY BE A COUPLE OF SHOTS OF BITTER COLD AIR.
PATTERN DOES NOT LOOK FAVORABLE FOR MUCH IN THE WAY OF WIDESPREAD
SYNOPTIC SNOWFALL OVER THE NEXT 7 DAYS. NEXT WEEK...LES WILL BE THE
MAIN PCPN CONCERN...MOSTLY FOR SNOWBELTS FAVORED BY W TO NW WINDS.
BEGINNING THU...WNW FLOW LES WILL GRADUALLY DIMINISH AS WEAK SFC
HIGH PRES RIDGE MOVES FROM THE UPPER MISSISSIPPI VALLEY TOWARD THE
UPPER LAKES. DGZ OCCUPIES A GOOD PORTION OF THE CONVECTIVE LAYER...
SO MIGHT BE ABLE TO FLUFF UP SEVERAL INCHES OF SNOW ACCUMULATION
THU. BEST ACCUMULATIONS SHOULD OCCUR IN FAR NRN ONTONAGON/CNTRL
HOUGHTON COUNTIES DUE TO CONVERGENT WRLY FLOW INTO THAT AREA AND
ALSO ERN ALGER/NRN LUCE COUNTIES WHERE MODELS DEPICT RATHER STRONG
LOW-LEVEL CONVERGENCE. ADVY TYPE HEADLINE MAY BE REQUIRED FOR THE
LATTER AREA.
WITH PASSAGE OF SFC HIGH PRES RIDGE THU NIGHT...LINGERING LES WILL
END AS WINDS SHIFT SW/OFFSHORE. FAVORED THE LOWER SIDE OF GUIDANCE
FOR MIN TEMPS WITH AT LEAST A PERIOD OF LIGHT WINDS AND PARTLY
CLOUDY SKIES IN MOST AREAS.
WAA PATTERN WILL BE IN FULL SWING FRI AS PACIFIC AIR SPREADS OUT
ACROSS THE NRN PLAINS IN DEVELOPING ZONAL FLOW. MIGHT BE A LITTLE
PCPN ACROSS NRN UPPER MI...BUT BETTER PCPN POTENTIAL WILL BE FARTHER
N WHERE SUFFICIENT LOW-LEVEL MOISTENING IS MORE LIKELY. TEMPS WILL
REACH THE 20S ACROSS THE BOARD.
WARMING WILL CONTINUE SAT AHEAD OF A SHORTWAVE TRACKING FROM
BC/PACIFIC NW TO THE NRN PLAINS. MOST LOCATIONS SHOULD TOP OUT
AROUND 30F. HOWEVER...A COLD FRONT DRIFTING S ACROSS UPPER MI WILL
INFLUENCE MAX TEMPS DEPENDING ON ITS TIMING. UPPER DIVERGENCE
ASSOCIATED WITH RIGHT ENTRANCE OF UPPER JET TO THE N AND NE SHOULD
SUPPORT A RIBBON OF -SN BEHIND THE SOUTHWARD DRIFTING COLD FRONT.
THAT -SN SHOULD BEGIN TO AFFECT NW UPPER MI SAT AFTN. AS COLD FRONT
CONTINUES TO DROP S SAT NIGHT/SUN MORNING...EXPECT MOST OF THE FCST
AREA TO SEE SOME -SN...AIDED BY RIGHT ENTRANCE UPPER DIVERGENCE.
SOME LAKE ENHANCEMENT SEEMS LIKELY FOR MOST IF NOT ALL OF NRN UPPER
MI AS WINDS WILL LIKELY SHIFT N FOR A TIME BEHIND COLD FRONT AND
POTENTIAL WEAK SFC WAVE THAT WILL ALSO BE TRACKING ALONG FRONT.
BEHIND THE COLD FRONT AND WITH THE PASSAGE OF ANOTHER SHORTWAVE
ROTATING THRU THE UPPER LAKES AROUND EXPANDING POLAR VORTEX...MUCH
COLDER AIR WILL DUMP INTO THE UPPER LAKES SAT NIGHT/SUN. THIS WILL
RESULT IN NW FLOW LES TAKING OVER SUN AS 850MB TEMPS PLUMMET INTO
THE LOW/MID -20S C. EXPECT SLOWLY FALLING TEMPS DURING THE DAY SUN.
PERSISTENT LES WILL THEN SET UP MON/TUE...MOSTLY FOR W TO WNW WIND
FAVORED SNOWBELTS...AS ACRTIC AIR SETTLES OVER THE AREA (850MB TEMPS
IN THE MID -20S C). LES WILL THEN CONTINUE THRU THE END OF NEXT WEEK
AS ARCTIC AIR WILL DOMINATE THE UPPER LAKES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1200 AM EST WED DEC 25 2013
IFR CONDITIONS WITH LIGHT SNOW WILL CONTINUE EARLY THIS FORECAST
PERIOD AS A TROF MOVES ACROSS THE AREA. AS THE SN DIMINISHES W-E BY
SUNRISE ON WED...MVFR SC CIGS WL LINGER. AS THE WEAKER FLOW VEERS
TOWARD THE W LATER ON WED MRNG...MORE SHSN/IFR VSBYS MAY IMPACT CMX
BY EARLY WED EVENING.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 531 AM EST WED DEC 25 2013
GALES EARLY TODAY FOR EASTERN PORTIONS OF LK SUPERIOR AS SOUTH
WINDS ARE ENHANCED BY PRESSURE FALLS TO NORTH OF LK SUPERIOR. EXPECT
WINDS TO DIMINISH TO LESS THAN 25 KTS LATER AFTN THROUGH TONIGHT.
WINDS WILL DIMINISH FURTHER TO 10-20KT ACROSS MOST OF LAKE SUPERIOR
THU/THU NIGHT AS A WEAK SFC HIGH PRES RIDGE PASSES. SW WINDS WILL
THEN INCREASE TO 15-25KT FRI AHEAD OF THE NEXT APPROACHING COLD
FRONT. AS THE FRONT DRIFTS S ACROSS THE AREA...WINDS WILL DIMINISH
FRI NIGHT/SAT MORNING. ARCTIC AIR WILL THEN SURGE INTO THE UPPER
LAKES LATE SAT THRU EARLY NEXT WEEK. MAY SEE SOME PERIODS OF GALES
EARLY NEXT WEEK ALONG WITH THE RETURN OF HVY FREEZING SPRAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR MIZ014-
085.
WINTER STORM WARNING UNTIL 1 PM EST THIS AFTERNOON FOR MIZ007.
LAKE SUPERIOR...
GALE WARNING UNTIL 7 AM EST THIS MORNING FOR LSZ266.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLA
LONG TERM...ROLFSON
AVIATION...07
MARINE...JLA/ROLFSON
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
608 AM CST WED DEC 25 2013
.UPDATE...
12Z AVIATION DISCUSSION ADDED BELOW.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 337 AM CST WED DEC 25 2013
TROUGHING AND CYCLONIC FLOW WILL DOMINATE THE SHORT TERM...WHICH
MEANS LOTS OF CLOUDS AND BOUTS OF LIGHT SNOW WILL DOMINATE THE NEXT
24 HOURS. LOOKING AT WATER VAPOR IMAGERY OVERLAID WITH RAP H5
VORTICITY YOU CAN SEE A COUPLE OF WAVES UPSTREAM IN THE NW FLOW THAT
WILL IMPACT US. THE FIRST IS CURRENTLY OVER ERN NODAK AND ALREADY
HAS SNOW MOVING ACROSS ERN SODAK AND NW MN AND WILL BE ARRIVING IN
THE MPX CWA SHORTLY. THE SECOND WAVE IS UP OVER NRN SASKATCHEWAN AND
WILL BE WORKING ACROSS MN THIS AFTERNOON. THESE UPPER WAVES WILL BE
WORKING WITH AN ELEVATED WARM FRONT IN THE H85-H7 LAYER TO THROW
SEVERAL BOUTS OF LIGHT SNOW OUR DIRECTION THROUGH THE PERIOD. THE
BEST BURST WILL BE THE INITIAL ONE THIS MORNING. THE HEAVIEST SNOW
HAS BEEN ALONG THAT ELEVATED WARM FRONT OVER ERN SODAK OVERNIGHT AND
FOLLOWED THE HRRR FOR BRINGING THIS SNOW DOWN THE MN RIVER THIS
MORNING. HAVE ENOUGH QPF OUT OF IT TO GET 0.5 TO 1 INCH SNOW AMOUNTS
FROM WC MN DOWN THE MN RIVER INTO SE MN. FOR THE REST OF THE
PERIOD...THE PATTERN IN PLACE LEADS TO LOW CONFIDENCE ON WHEN/WHERE
THESE LITTLE BURSTS OF SNOW WILL COME DOWN...SO THERE ARE LOTS OF
SMALL POPS THROUGH 9Z TONIGHT...WHICH IS WHEN THE SREF AND HIRES
MODELS FINALLY SHOW SNOW CHANCES EVACUATING THE MPX CWA...FOR A
SHORT TIME ANYWAYS.
TEMPERATURES WILL BE TRICKY THIS PERIOD AS WELL THANKS TO A SFC WARM
FRONT THAT AT 3AM WAS NEAR A ROSEAU/LONG PRAIRIE/TWIN CITIES/ALBERT
LEA LINE. TEMPERATURES EAST OF THIS BOUNDARY HAVE REMAINED IN THE
SINGLE DIGITS...WITH TEMPERATURES SLOWLY RISING INTO THE TEENS AND
EVEN LOWER 20S BY THE TIME YOU GET TO THE MN/SD BORDER. THE COLD
FRONT WAS ALIGNED FROM A WEAK SFC LOW NEAR GRAND FORKS BACK NW INTO
CENTRAL SASKATCHEWAN. THE WARM SECTOR ACROSS THE DAKOTAS HAS BEEN
QUITE IMPRESSIVE THIS MORNING...WITH SEVERAL LOCATIONS ACROSS THE
CENTRAL DAKOTAS WARMING TO BETWEEN 32 AND 34 DEGREES /ABOUT 35
DEGREES WARMER THAN THIS TIME 24 HOURS AGO!/. THE QUESTION FOR
TODAY...IS HOW MUCH OF THIS WARM SECTOR CAN WE GET INTO THE MPX CWA.
THE CORE OF THE WARMEST AIR LOOKS TO DROP SOUTHWEST OF THE MPX
CWA...BUT WE SHOULD STILL SEE TEMPS RISE INTO THE UPPER 20S ACROSS
WRN MN THIS MORNING...BEFORE THE COLD FRONT ARRIVES THIS AFTERNOON
TO START SENDING TEMPERATURES THE OTHER DIRECTION.
FOR TONIGHT THE TWO VARIABLES TO WATCH ARE WHAT HAPPENS WITH CLOUD
COVER AND WHERE DOES THAT COLD FRONT END UP. AS FOR THE FRONT...MOST
MODELS SHOW THE FRONT BECOMING STATIONARY ACROSS SW MN...WITH
ANOTHER PUNCH OF ARCTIC AIR SLIDING DOWN ACROSS AREAS MAINLY NORTH
OF I-94. THIS WILL KEEP TEMPERATURES TONIGHT IN THE MN RIVER VALLEY
ON SOUTH UP IN THE TEENS...BUT BACK NORTH OF I-94...IF SKIES CAN
STAY SUFFICIENTLY CLEAR...WE COULD SEE MORE WIDESPREAD DOUBLE DIGIT
LOWS BELOW ZERO. IT/S NOT OUT OF THE REAL OF POSSIBILITY TO SEE A
NEARLY A NEARLY 30 DEGREE SPREAD IN LOWS TONIGHT ACROSS THE MPX
CWA...WITH LOWS AROUND 15 ABOVE OUT IN WRN MN AND AROUND 15 BELOW
ALONG THE US-8 CORRIDOR IN WRN WI.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 337 AM CST WED DEC 25 2013
THE FORECAST WARM UP FOR THE LATER HALF OF THE WEEK STILL LOOKS TO
BE ON SCHEDULE. SHOULD SEE MODERATING TEMPERATURES INTO SATURDAY
WITH ANOTHER WAFT OF PACIFIC AIR MOVING THROUGH...AHEAD OF NEXT
ARCTIC COLD FRONT. MODELS TREND ANOTHER SHOT OF SNOW ASSOCIATED
WITH THE INITIAL PACIFIC AIR INTRUSION ON THURSDAY. AT THE
MOMENT...HAVE INCLUDED A SMALL LIKELY POP AREA OVER THE NORTHEAST
CWA. SIGNIFICANT MOISTURE APPEARS TO BE LACKING AND MOST MODELS
HAVING TROUBLE SATURATING AS THE PRECIPITATION BAND MOVES FARTHER
EAST. ANY SNOWFALL SHOULD REMAIN LIGHT FOR THIS SYSTEM.
DO EXPECT SOME LOWER 30S AT LEAST AHEAD OF THE ARCTIC BOUNDARY AS
THAT ARRIVES SATURDAY AFTERNOON. WITH STEEP LOW LEVEL LAPSE
RATES...STRONG WIND GUSTS EXPECTED TO MATERIALIZE. 35 KT WIND
GUSTS LOOK LIKELY AS THE SYSTEM MOVES THROUGH. THE BETTER CHANCE
OF SNOW SHOWERS SHOULD RIDE FARTHER EAST...BUT IF THEY DO COINCIDE
WITH THE STRONGEST WINDS...COULD SEE NEAR BLIZZARD CONDITIONS
DEVELOP OVER THE SOUTHWEST/MINNESOTA RIVER VALLEY REGION SATURDAY
AFTERNOON/EVENING. HAVE CONTINUED TO INCLUDE SOME BLOWING SNOW
OVER THE REGION FOR THIS PERIOD...INTO SUNDAY.
THE NEXT SURGE OF ARCTIC AIR DROPS OVER THE REGION SUNDAY AND
LINGERS THROUGH MUCH OF THE COMING WEEK. NORTHWEST FLOW PATTERN
WILL LEAVE THE REGION IN THE FAVORABLE AREA FOR MORE LIGHT/FLUFFY
SNOW EVENTS. MONDAY NIGHT INTO TUESDAY NIGHT LOOKS LIKE THE NEXT
BEST CHANCE OF SOME LIGHT SNOW. HAVE LOW POPS FOR NOW. WILL HOLD
OFF ON HIGHER POPS FOR NOW...TO GET BETTER TIMING AS WE GET CLOSER
TO THE EVENT. WIND CHILLS WILL ONCE AGAIN BECOME AN ISSUE AS THE
COLD AIR ARRIVES AS WELL. THE 00Z ECMWF SHOWS LITTLE MODERATION IN
TEMPERATURES IN THE LONGER TERM...WHICH WOULD TAKE US INTO THE
FIRST WEEK OF THE NEW YEAR.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 540 AM CST WED DEC 25 2013
THE COMBINATION OF CYCLONIC FLOW AND A WARM FRONT LAYING OUT
ACROSS THE AREA THIS TAF PERIOD WILL RESULT IN PLENTY OF CLOUD
COVER WITH NUMEROUS BOUTS OF LIGHT SNOW. MOST CONFIDENCE ON THE
SNOW EXISTS WITH BURST CURRENTLY WORKING ACROSS THE AREA. HAVE
CONTINUED TO FOLLOW THE HRRR TO TREND THIS SNOW THROUGH THE
TERMINALS. EXPECT IFR VSBY SNOW TO REMAIN SOUTH OF ALL TERMINALS
BUT RWF...WITH THE REST JUST DEALING WITH 2 TO 4 HOURS OF
INTERMITTENT MVFR SNOWS THIS MORNING. AFTER THAT...SREF PROBS AND
HIGH-RES MODELS SHOW A RATHER CHAOTIC SNOW PICTURE PLAYING OUT
THROUGH TONIGHT. GIVEN THE LOW CONFIDENCE ON WHEN/WHERE FUTURE
BANDS OF SNOW WILL EXIST...LEFT ANY SNOW MENTION BEYOND THIS
MORNING OUT...THOUGH IN ALL LIKELIHOOD MORE MVFR TYPE SNOWS WILL
BE SEEN FROM TIME TO TIME BEYOND THIS MORNING. CIGS WILL MOSTLY
STAY MVFR THROUGH THE MORNING...BUT AS A COLD FRONT SLOWLY SLIDES
SOUTH THROUGH THE AREA THIS AFTERNOON/EVENING WILL LIKELY SEE SOME
BREAKS IN THE CLOUDS...THOUGH CLOUD COVER WILL DOMINATE THE SCENE.
LOW CONFIDENCE BEYOND THIS AFTERNOON WITH CIG HEIGHTS...SO WENT
CONSERVATIVE WITH CIGS BECOMING VFR THIS EVENING...THOUGH WE WILL
PROBABLY SEE MVFR OR LOWER CIGS AT TIMES RIGHT THROUGH THE END OF
THE PERIOD. WINDS WILL BE STRONGEST THIS MORNING/EARLY AFTERNOON
AHEAD OF THE COLD FRONT OVER SW MN...WILL LIKELY SEE SOME
BLSN...THOUGH HARD TO SAY IF IT WILL LEAD TO VIS RESTRICTIONS AT
RWF...BUT LEFT THAT IDEA IN FROM THE PREVIOUS TAF.
KMSP...BASED ON RADAR...LOOKING LIKE HEAVIEST SNOW WILL GO SOUTH
AND NORTH OF THE FIELD...THOUGH A PERIOD OF MVFR VSBYS STILL LOOKS
LIKELY THIS MORNING. WILL LIKELY BE MORE SNOW AFTER THIS
MORNING...BUT CONFIDENCE TOO LOW ON WHEN ADDITIONAL SNOW SHOWERS
WILL OCCUR TO INCLUDE IN THE TAF AT THIS TIME. BASED ON UPSTREAM
OBS...CIGS CURRENTLY ABOVE 017 LOOK TO BE SHORT LIVED...WITH CIGS
MAINLY 012-015 NW OF MSP. CONFIDENCE IN CIG FORECAST THIS
AFTERNOON ON IS LOW. WINDS LOOK TO GO NORTH OF 240 BETWEEN 16Z AND
18Z...SO WILL EVENTUALLY HAVE TO GET EVERYTHING OVER TO THE 30S
THIS AFTERNOON.
/OUTLOOK FOR KMSP/
THU...CHANCE MVFR CIGS/VSBYS IN -SN. WINDS S AT 5 KTS.
FRI...VFR. WINDS SW 5-10 KTS.
SAT...VFR. CHC MVFR/-SN LATE. WINDS SW 5-10 KTS BCMG NW 20G30KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...MPG
LONG TERM...DWE
AVIATION...MPG
AREA FORECAST DISCUSSION
NWS HASTINGS NE
542 AM CST WED DEC 25 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 407 AM CST WED DEC 25 2013
WITH ESSENTIALLY ZERO RISK OF PRECIP THROUGH THE NEXT 24
HOURS...THE MAIN FORECAST ISSUES INVOLVE TEMPS/SKY COVER/AND HOW
BREEZY IT WILL GET TODAY. TEMP-WISE...WHAT WOULD OTHERWISE BE A
FAIRLY STRAIGHTFORWARD SITUATION IS COMPLICATED SOMEWHAT BY SOME
MODELS/GUIDANCE STRUGGLING WITH THE INITIALIZATION OF EXISTING
SNOW COVER.
STARTING OFF EARLY THIS CHRISTMAS MORNING...ALL IS QUIET...AS THE
LATEST 11-3.9 MICRON SATELLITE IMAGERY INDICATES ESSENTIALLY CLEAR
SKIES CWA-WIDE...IN THE WAKE OF LOW STRATUS THAT HAS PUSHED EAST
OF THE AREA...AND A BATCH OF MID LEVEL CLOUDS THAT HAS PUSHED
SOUTH OF THE CWA. WATER VAPOR SATELLITE IMAGERY AND SHORT TERM
MODEL DATA INDICATE A BROAD MID-UPPER TROUGH CENTERED OVER THE
CENTRAL CONUS NORTHWARD INTO SOUTH CENTRAL CANADA...WHILE FARTHER
WEST...A LARGE-SCALE RIDGE IS CENTERED OFF THE CA COAST IN THE
PACIFIC. WITHIN THE LARGE SCALE TROUGH OVER THE LOCAL AREA...THERE
ARE FEW SMALLER SCALE SHORTWAVE TROUGHS OF INTEREST...ONE OF WHICH
IS CURRENTLY ORIENTED SOUTHWEST-NORTHEAST FROM SOUTHWEST KS-
NORTHERN MO...AND IS EXITING THE SOUTHEAST CWA AT THIS TIME.
MEANWHILE...ANOTHER CLIPPER-TYPE NORTHWEST-FLOW SHORTWAVE IS IN
THE PROCESS OF DROPPING SOUTHWARD INTO THE DAKOTAS/MN...WITHIN THE
EXIT REGION OF A STOUT 120+KT NORTHERLY JET STREAK EVIDENT AT 300
MILLIBARS THAT IS CURRENTLY POKING SOUTHWARD INTO MT OUT OF
SASKATCHEWAN. AT THE SURFACE...09Z OBJECTIVE ANALYSIS AND
AUTOMATED OBS REVEAL A FAIRLY UNIFORM FIELD OF WESTERLY BREEZES
GENERALLY 5-10 MPH ACROSS THE CWA...DRIVEN WITHIN A FAIRLY WEAK
PRESSURE GRADIENT BETWEEN A 1029MB HIGH CENTERED OVER THE NEB/CO
BORDER AREA AND EXTENDING SOUTHEAST ACROSS KS...AND A 1015MB LOW
CENTERED OVER NORTHWEST MN ASSOCIATED WITH THE AFOREMENTIONED
CLIPPER. TEMP-WISE EARLY THIS MORNING...AS WESTERLY BREEZES HAVE
BECOME MORE ESTABLISHED MOST PLACES HAVE LARGELY LEVELED OFF THE
NOCTURNAL DROP OR EVEN RISEN SOMEWHAT FROM VALUES EARLIER IN THE
NIGHT...BUT GIVEN THE CLEAR SKIES...SOME LOCALIZED DROPS ARE STILL
LIKELY BEFORE THE NIGHT IS THROUGH. ACTUAL LOWS FOR THE NIGHT
ALREADY HAVE BEEN...OR WILL EVENTUALLY BE...SOMEWHERE BETWEEN
15-21 ACROSS MOST OF THE CWA.
FOR THE DAYTIME HOURS TODAY...THE MAIN STORY IN THE MID-UPPER
LEVELS INVOLVES THE SOUTH-SOUTHEAST PROGRESSION OF THE
AFOREMENTIONED CLIPPER SYSTEM...WHICH WILL MAINLY TAKE AIM ON THE
MN/IA REGION AS THE MAIN VORTICITY MAXIMUM AT 500MB ENDS UP OVER
NORTHERN MN BY 00Z/6PM TODAY. GIVEN THE TRACK OF THIS SYSTEM AND
ITS FORCING FIELDS...ANY LIGHT PRECIP TODAY SHOULD MAINLY FOCUS
ALONG A TRACK FROM EASTERN SD ACROSS SOUTHERN MN/NORTHERN IA...AND
MAYBE AS FAR SOUTHWEST AS EXTREME NORTHEAST NEB. ALONG THESE SAME
LINES...THE VAST MAJORITY OF THE CWA SHOULD SEE NOTHING MORE THAN
LIMITED MID-HIGH CLOUD COVER TODAY...WITH SKIES AVERAGING OUT TO
NO WORSE THAN MOSTLY SUNNY. THAT BEING SAID...MODELS SUCH AS THE
06Z NAM AND TO A GREATER EXTENT THE 08Z RAP 13 SHOW THAT THE
SOUTHWEST EDGES OF WHAT COULD BE A FAIRLY SOLID BATCH OF LOWER
STRATUS COULD COME VERY CLOSE TO INFILTRATING A FEW COUNTIES IN
THE FAR NORTHEAST CWA SUCH AS NANCE/POLK...ALTHOUGH THE VAST
MAJORITY OF THIS CLOUD MASS SHOULD PASS 50+ MILES EAST/NORTHEAST
OF THE CWA. ALTHOUGH THE OFFICIAL FORECAST RUNS WITH THE
ASSUMPTION THAT SKIES BECOME NO WORSE THAN PARTLY CLOUDY FOR A FEW
HOURS IN THESE FAR NORTHEAST AREAS...THIS WILL BARE WATCHING AS
THE RAP 900/850MB RELATIVE HUMIDITY FIELDS ARE CURRENTLY HANDLING
UPSTREAM LOWER CLOUDS OVER NORTH CENTRAL/EASTERN SD PRETTY WELL.
TURNING TO THE SURFACE SITUATION...THE MAIN FEATURE TODAY WILL BE
SEVERAL HOURS OF INCREASED NORTHWEST BREEZES...AS ENHANCED LOWER
LEVEL WINDS MIX DOWN TO THE SURFACE AS MIXING HEIGHTS INCREASE TO
AROUND 875MB. THE PRIMARY PERIOD OF ENHANCED NORTHWEST BREEZES
WILL FOCUS BETWEEN 15Z/9AM TO 22Z/4PM...WITH SUSTAINED SPEEDS
15-20 MPH AND GUSTS AT LEAST 20-25 MPH...AND GENERALLY STRONGEST
ACROSS THE NORTHEAST 1/2 OF THE CWA. ALTHOUGH THIS NORTHWESTERLY
WIND TECHNICALLY RESULTS IN AT LEAST WEAK COLD AIR ADVECTION ABOVE
THE SURFACE EVIDENT AT 850MB...THE COMBINATION OF SUNSHINE AND
DECENT MIXING SHOULD RESULT IN A CONSIDERABLY MILDER
DAY...ESPECIALLY IN THOSE CENTRAL/EASTERN COUNTIES THAT REMAINED
QUITE CLOUDY TUESDAY. AS HAS BEEN TYPICAL LATELY...TEMPERATURE
FIELDS IN MODELS SUCH AS THE NAM12 AND ASSOCIATED GUIDANCE ARE
HEAVILY CONTAMINATED BY OVER-ZEALOUS SNOW COVER INITIALIZATION.
FORTUNATELY...THE HOURLY TEMP FIELD OF THE RAP13 LOOKED QUITE
REASONABLE AND UNCONTAMINATED...AND THUS WAS FOLLOWED VERY CLOSELY
TODAY. THIS RESULTED IN SIMILAR HIGH TEMPS TO PREVIOUS
FORECAST...BUT 1-2 DEGREES WARMER IN MANY CENTRAL/SOUTHERN AREAS.
THE NET RESULT IS A RANGE FROM UPPER 30S NORTH...LOW 40S CENTRAL
AND MID 40S SOUTH...ALTHOUGH A RESPECTABLE 1-3 INCHES OF SNOW
COVER CENTERED OVER MUCH OF FURNAS/GOSPER/HARLAN COUNTIES WILL
LIKELY KEEP THOSE AREAS A BIT COOLER THAN BORDERING
AREAS...GENERALLY UPPER 30S.
TURNING TO THIS EVENING/TONIGHT...A RATHER QUIET AND PRECIP-FREE
FORECAST CONTINUES. IN THE MID/UPPER LEVELS...MODEST HEIGHT RISES
WILL BE EVIDENT AT 500MB OVER THE LOCAL AREAS...IN THE WAKE OF THE
FAIRLY VIGOROUS CLIPPER SYSTEM DEPARTING EASTWARD INTO THE LOWER
GREAT LEGION. MEANWHILE THOUGH...A WEAKER/MORE SUBTLE NORTHWEST-
FLOW DISTURBANCE WILL GRADUALLY APPROACH THE CENTRAL PLAINS FROM
THE NORTHERN ROCKIES...REACHING THE SD/NORTHWEST NEB AREA BY
SUNRISE THURSDAY. LOCALLY...THE ONLY EFFECT OF THIS INCOMING WEAK
WAVE WILL BE A MODEST INCREASE IN MAINLY HIGH LEVEL CLOUDS
ESPECIALLY OVER NORTHERN ZONES...BUT EVEN SO...OVERNIGHT SKIES ARE
FORECAST TO AVERAGE NO WORSE THAN MOSTLY CLEAR ACROSS THE MAJORITY
OF THE CWA. AT THE SURFACE...WEAK PRESSURE FALLS CENTERED OVER THE
DAKOTAS WILL ALLOW LOCAL BREEZES TO TRANSITION FROM NORTHWESTERLY
THIS AFTERNOON TO A WEST-SOUTHWEST DIRECTION AT GENERALLY 5-10 MPH
THROUGH THE OVERNIGHT HOURS. ALTHOUGH THESE WESTERLY BREEZES WILL
INDUCE MODEST WARM AIR ADVECTION ALOFT EVIDENT AT 850MB...THE
FAIRLY LIGHT SPEEDS WILL PROBABLY NOT BE ENOUGH TO OFFSET A DECENT
TEMP DROP UNDER THE MOSTLY CLEAR SKIES. THUS TOOK A MIDDLE-GROUND
APPROACH ON LOW TEMPS...MAKING VERY LITTLE CHANGE FROM PREVIOUS
FORECAST VIA A MULTI-MODEL BLEND...RESULTING IN A FAIRLY UNIFORM
LOW TEMPERATURE FIELD OF 16-20 ACROSS THE CWA. THIS IS GENERALLY
2-4 DEGREES MILDER THAN A BLEND OF 00Z MET/MAV GUIDANCE WHICH
APPEARS TO BE A BIT TOO COLD...BUT IS NOT AS WARM AS RAW 2M TEMPS
PRESENTED BY MODELS SUCH AS THE GFS/ECMWF. AS IS TYPICAL IN THESE
OVERNIGHT WESTERLY WIND REGIMES THOUGH...THERE WILL LIKELY BE
SCATTERED NON-DIURNAL TEMP TENDENCIES ACROSS PARTS OF THE AREA.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 407 AM CST WED DEC 25 2013
THURSDAY THROUGH NEW YEARS EVE DAY/TUESDAY. THE LATTER
PART OF THE WEEK INTO THE FIRST PART OF THE WEEKEND ARE STILL
SHAPING UP TO BE THE NICEST/WARMEST DAYS OF THE EXTENDED TIME
FRAME. A NORTHWEST FLOW PATTERN WILL BE IN PLACE ACROSS OUR REGION
WHILE THE UPPER TROUGH AND COLD AIR THROUGH THE OHIO VALLEY REGION
LIFTS OUT ACROSS THE NORTHEAST CONUS. A WARMER AIRMASS WILL
SETTLE IN FOR A FEW DAYS AND A DRY DOWNSLOPE WESTERLY WIND COMPONENT
WILL AID IN THE TEMP WARMUP FOR OUR AREA. HIGH ON THURSDAY SHOULD
AVERAGE IN THE LOW/MID 40S...WITH EVEN WARMER 50S EXPECTED FOR
FRIDAY.
TEMPERATURES ON SATURDAY WILL BE DEPENDENT UPON THE TIMING OF A
STRONG COLD FRONTAL PASSAGE WHICH IS PROGGED TO CROSS OUR CWA DURING
THE AFTN/EVENING. IF TIMING TRENDS FASTER...TEMPS WILL NOT BE AS
WARM AS CURRENT FORECAST ESPECIALLY ACROSS OUR NORTHERN ZONES AND
THERMAL GRADIENT WILL NEED TO BE TIGHTENED. THE 6HR PRESSURE RISES
BEHIND FRONT AVERAGE 11MB AND EXPECT A PERIOD OF STRONG/GUSTY NORTH
WINDS FOLLOWING FROPA AND HAVE RAMPED UP WIND SPEEDS HIGHER THAN
WHAT INIT PROVIDED. MODELS ALSO SUGGEST LOW CLOUDS MOVING IN BEHIND
BOUNDARY AND AS PREVIOUS DISCUSSION MENTIONED...COULD SEE SOME
FLURRIES SATURDAY EVENING/NIGHT IN PRESENCE OF FRONTOGENESIS...AND
IS SOMETHING TO MONITOR.
A 1035MB SURFACE HIGH BUILDS SOUTH ONTO THE PLAINS SUNDAY BEHIND THE
COLD FRONT AND TEMPERATURES WILL DROP BACK BELOW SEASONAL NORMALS
FOR A COUPLE OF DAYS. THE AIRMASS LOOKS TO MODERATE SOME FROM LATE
MONDAY INTO TUESDAY/NEW YEARS EVE DAY AND TEMPS NEAR NORMAL APPEAR
REASONABLE FOR NOW. THIS BEING SAID...A COLD AIRMASS IS NOT THAT FAR
AWAY AS A TROUGH DEEPENS OVER THE HUDSON BAY.
&&
.AVIATION...(FOR THE 12Z KGRI TAF THROUGH 12Z THURSDAY MORNING)
ISSUED AT 542 AM CST WED DEC 25 2013
CONFIDENCE REMAINS HIGH IN VFR CEILING/VISIBILITY THROUGHOUT THE
PERIOD...WITH ONLY LIMITED AMOUNTS OF PASSING MID/HIGH CLOUD
COVER...AND ANY DAYTIME BATCHES OF LOWER MVFR HEIGHT STRATUS
LIKELY TO REMAIN AT LEAST 60-80 MILES NORTHEAST OF KGRI. AS FOR
SURFACE WINDS...MADE VERY LITTLE CHANGE TO PREVIOUS
FORECAST...WITH BREEZES BOTH RIGHT AWAY EARLY THIS MORNING AND
AGAIN THIS EVENING/TONIGHT AVERAGING FROM A WESTERLY DIRECTION
NEAR/UNDER 10KT. HOWEVER...FOR SEVERAL HOURS TODAY ESPECIALLY
BETWEEN 17Z-20Z...NORTHWEST WINDS WILL INCREASE TO SUSTAINED
SPEEDS NEAR 16KT WITH GUST POTENTIAL TO AROUND 23KT...BEFORE
SUBSIDING LATE THIS AFTERNOON. PRIOR TO THE ONSET OF THE ENHANCED
BREEZES AT THE SURFACE...THERE WILL LIKELY BE AT LEAST A FEW HOURS
OF MODEST LOW LEVEL WIND SHEAR AS WINDS ACCELERATE INTO THE
40-45KT RANGE FROM THE NORTHWEST WITHIN THE LOWEST 1500 FT AGL.
GIVEN THAT THE WIND VECTOR MAGNITUDE DIFFERENCE BETWEEN THE
SURFACE AND THIS LEVEL IS FORECAST TO BE AT LEAST
35KT...INSERTED A FORMAL MENTION OF LLWS FROM 14Z-16Z THIS
MORNING.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...PFANNKUCH
LONG TERM...FAY
AVIATION...PFANNKUCH
AREA FORECAST DISCUSSION
NWS HASTINGS NE
407 AM CST WED DEC 25 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 407 AM CST WED DEC 25 2013
WITH ESSENTIALLY ZERO RISK OF PRECIP THROUGH THE NEXT 24
HOURS...THE MAIN FORECAST ISSUES INVOLVE TEMPS/SKY COVER/AND HOW
BREEZY IT WILL GET TODAY. TEMP-WISE...WHAT WOULD OTHERWISE BE A
FAIRLY STRAIGHTFORWARD SITUATION IS COMPLICATED SOMEWHAT BY SOME
MODELS/GUIDANCE STRUGGLING WITH THE INITIALIZATION OF EXISTING
SNOW COVER.
STARTING OFF EARLY THIS CHRISTMAS MORNING...ALL IS QUIET...AS THE
LATEST 11-3.9 MICRON SATELLITE IMAGERY INDICATES ESSENTIALLY CLEAR
SKIES CWA-WIDE...IN THE WAKE OF LOW STRATUS THAT HAS PUSHED EAST
OF THE AREA...AND A BATCH OF MID LEVEL CLOUDS THAT HAS PUSHED
SOUTH OF THE CWA. WATER VAPOR SATELLITE IMAGERY AND SHORT TERM
MODEL DATA INDICATE A BROAD MID-UPPER TROUGH CENTERED OVER THE
CENTRAL CONUS NORTHWARD INTO SOUTH CENTRAL CANADA...WHILE FARTHER
WEST...A LARGE-SCALE RIDGE IS CENTERED OFF THE CA COAST IN THE
PACIFIC. WITHIN THE LARGE SCALE TROUGH OVER THE LOCAL AREA...THERE
ARE FEW SMALLER SCALE SHORTWAVE TROUGHS OF INTEREST...ONE OF WHICH
IS CURRENTLY ORIENTED SOUTHWEST-NORTHEAST FROM SOUTHWEST KS-
NORTHERN MO...AND IS EXITING THE SOUTHEAST CWA AT THIS TIME.
MEANWHILE...ANOTHER CLIPPER-TYPE NORTHWEST-FLOW SHORTWAVE IS IN
THE PROCESS OF DROPPING SOUTHWARD INTO THE DAKOTAS/MN...WITHIN THE
EXIT REGION OF A STOUT 120+KT NORTHERLY JET STREAK EVIDENT AT 300
MILLIBARS THAT IS CURRENTLY POKING SOUTHWARD INTO MT OUT OF
SASKATCHEWAN. AT THE SURFACE...09Z OBJECTIVE ANALYSIS AND
AUTOMATED OBS REVEAL A FAIRLY UNIFORM FIELD OF WESTERLY BREEZES
GENERALLY 5-10 MPH ACROSS THE CWA...DRIVEN WITHIN A FAIRLY WEAK
PRESSURE GRADIENT BETWEEN A 1029MB HIGH CENTERED OVER THE NEB/CO
BORDER AREA AND EXTENDING SOUTHEAST ACROSS KS...AND A 1015MB LOW
CENTERED OVER NORTHWEST MN ASSOCIATED WITH THE AFOREMENTIONED
CLIPPER. TEMP-WISE EARLY THIS MORNING...AS WESTERLY BREEZES HAVE
BECOME MORE ESTABLISHED MOST PLACES HAVE LARGELY LEVELED OFF THE
NOCTURNAL DROP OR EVEN RISEN SOMEWHAT FROM VALUES EARLIER IN THE
NIGHT...BUT GIVEN THE CLEAR SKIES...SOME LOCALIZED DROPS ARE STILL
LIKELY BEFORE THE NIGHT IS THROUGH. ACTUAL LOWS FOR THE NIGHT
ALREADY HAVE BEEN...OR WILL EVENTUALLY BE...SOMEWHERE BETWEEN
15-21 ACROSS MOST OF THE CWA.
FOR THE DAYTIME HOURS TODAY...THE MAIN STORY IN THE MID-UPPER
LEVELS INVOLVES THE SOUTH-SOUTHEAST PROGRESSION OF THE
AFOREMENTIONED CLIPPER SYSTEM...WHICH WILL MAINLY TAKE AIM ON THE
MN/IA REGION AS THE MAIN VORTICITY MAXIMUM AT 500MB ENDS UP OVER
NORTHERN MN BY 00Z/6PM TODAY. GIVEN THE TRACK OF THIS SYSTEM AND
ITS FORCING FIELDS...ANY LIGHT PRECIP TODAY SHOULD MAINLY FOCUS
ALONG A TRACK FROM EASTERN SD ACROSS SOUTHERN MN/NORTHERN IA...AND
MAYBE AS FAR SOUTHWEST AS EXTREME NORTHEAST NEB. ALONG THESE SAME
LINES...THE VAST MAJORITY OF THE CWA SHOULD SEE NOTHING MORE THAN
LIMITED MID-HIGH CLOUD COVER TODAY...WITH SKIES AVERAGING OUT TO
NO WORSE THAN MOSTLY SUNNY. THAT BEING SAID...MODELS SUCH AS THE
06Z NAM AND TO A GREATER EXTENT THE 08Z RAP 13 SHOW THAT THE
SOUTHWEST EDGES OF WHAT COULD BE A FAIRLY SOLID BATCH OF LOWER
STRATUS COULD COME VERY CLOSE TO INFILTRATING A FEW COUNTIES IN
THE FAR NORTHEAST CWA SUCH AS NANCE/POLK...ALTHOUGH THE VAST
MAJORITY OF THIS CLOUD MASS SHOULD PASS 50+ MILES EAST/NORTHEAST
OF THE CWA. ALTHOUGH THE OFFICIAL FORECAST RUNS WITH THE
ASSUMPTION THAT SKIES BECOME NO WORSE THAN PARTLY CLOUDY FOR A FEW
HOURS IN THESE FAR NORTHEAST AREAS...THIS WILL BARE WATCHING AS
THE RAP 900/850MB RELATIVE HUMIDITY FIELDS ARE CURRENTLY HANDLING
UPSTREAM LOWER CLOUDS OVER NORTH CENTRAL/EASTERN SD PRETTY WELL.
TURNING TO THE SURFACE SITUATION...THE MAIN FEATURE TODAY WILL BE
SEVERAL HOURS OF INCREASED NORTHWEST BREEZES...AS ENHANCED LOWER
LEVEL WINDS MIX DOWN TO THE SURFACE AS MIXING HEIGHTS INCREASE TO
AROUND 875MB. THE PRIMARY PERIOD OF ENHANCED NORTHWEST BREEZES
WILL FOCUS BETWEEN 15Z/9AM TO 22Z/4PM...WITH SUSTAINED SPEEDS
15-20 MPH AND GUSTS AT LEAST 20-25 MPH...AND GENERALLY STRONGEST
ACROSS THE NORTHEAST 1/2 OF THE CWA. ALTHOUGH THIS NORTHWESTERLY
WIND TECHNICALLY RESULTS IN AT LEAST WEAK COLD AIR ADVECTION ABOVE
THE SURFACE EVIDENT AT 850MB...THE COMBINATION OF SUNSHINE AND
DECENT MIXING SHOULD RESULT IN A CONSIDERABLY MILDER
DAY...ESPECIALLY IN THOSE CENTRAL/EASTERN COUNTIES THAT REMAINED
QUITE CLOUDY TUESDAY. AS HAS BEEN TYPICAL LATELY...TEMPERATURE
FIELDS IN MODELS SUCH AS THE NAM12 AND ASSOCIATED GUIDANCE ARE
HEAVILY CONTAMINATED BY OVER-ZEALOUS SNOW COVER INITIALIZATION.
FORTUNATELY...THE HOURLY TEMP FIELD OF THE RAP13 LOOKED QUITE
REASONABLE AND UNCONTAMINATED...AND THUS WAS FOLLOWED VERY CLOSELY
TODAY. THIS RESULTED IN SIMILAR HIGH TEMPS TO PREVIOUS
FORECAST...BUT 1-2 DEGREES WARMER IN MANY CENTRAL/SOUTHERN AREAS.
THE NET RESULT IS A RANGE FROM UPPER 30S NORTH...LOW 40S CENTRAL
AND MID 40S SOUTH...ALTHOUGH A RESPECTABLE 1-3 INCHES OF SNOW
COVER CENTERED OVER MUCH OF FURNAS/GOSPER/HARLAN COUNTIES WILL
LIKELY KEEP THOSE AREAS A BIT COOLER THAN BORDERING
AREAS...GENERALLY UPPER 30S.
TURNING TO THIS EVENING/TONIGHT...A RATHER QUIET AND PRECIP-FREE
FORECAST CONTINUES. IN THE MID/UPPER LEVELS...MODEST HEIGHT RISES
WILL BE EVIDENT AT 500MB OVER THE LOCAL AREAS...IN THE WAKE OF THE
FAIRLY VIGOROUS CLIPPER SYSTEM DEPARTING EASTWARD INTO THE LOWER
GREAT LEGION. MEANWHILE THOUGH...A WEAKER/MORE SUBTLE NORTHWEST-
FLOW DISTURBANCE WILL GRADUALLY APPROACH THE CENTRAL PLAINS FROM
THE NORTHERN ROCKIES...REACHING THE SD/NORTHWEST NEB AREA BY
SUNRISE THURSDAY. LOCALLY...THE ONLY EFFECT OF THIS INCOMING WEAK
WAVE WILL BE A MODEST INCREASE IN MAINLY HIGH LEVEL CLOUDS
ESPECIALLY OVER NORTHERN ZONES...BUT EVEN SO...OVERNIGHT SKIES ARE
FORECAST TO AVERAGE NO WORSE THAN MOSTLY CLEAR ACROSS THE MAJORITY
OF THE CWA. AT THE SURFACE...WEAK PRESSURE FALLS CENTERED OVER THE
DAKOTAS WILL ALLOW LOCAL BREEZES TO TRANSITION FROM NORTHWESTERLY
THIS AFTERNOON TO A WEST-SOUTHWEST DIRECTION AT GENERALLY 5-10 MPH
THROUGH THE OVERNIGHT HOURS. ALTHOUGH THESE WESTERLY BREEZES WILL
INDUCE MODEST WARM AIR ADVECTION ALOFT EVIDENT AT 850MB...THE
FAIRLY LIGHT SPEEDS WILL PROBABLY NOT BE ENOUGH TO OFFSET A DECENT
TEMP DROP UNDER THE MOSTLY CLEAR SKIES. THUS TOOK A MIDDLE-GROUND
APPROACH ON LOW TEMPS...MAKING VERY LITTLE CHANGE FROM PREVIOUS
FORECAST VIA A MULTI-MODEL BLEND...RESULTING IN A FAIRLY UNIFORM
LOW TEMPERATURE FIELD OF 16-20 ACROSS THE CWA. THIS IS GENERALLY
2-4 DEGREES MILDER THAN A BLEND OF 00Z MET/MAV GUIDANCE WHICH
APPEARS TO BE A BIT TOO COLD...BUT IS NOT AS WARM AS RAW 2M TEMPS
PRESENTED BY MODELS SUCH AS THE GFS/ECMWF. AS IS TYPICAL IN THESE
OVERNIGHT WESTERLY WIND REGIMES THOUGH...THERE WILL LIKELY BE
SCATTERED NON-DIURNAL TEMP TENDENCIES ACROSS PARTS OF THE AREA.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 407 AM CST WED DEC 25 2013
THURSDAY THROUGH NEW YEARS EVE DAY/TUESDAY. THE LATTER
PART OF THE WEEK INTO THE FIRST PART OF THE WEEKEND ARE STILL
SHAPING UP TO BE THE NICEST/WARMEST DAYS OF THE EXTENDED TIME
FRAME. A NORTHWEST FLOW PATTERN WILL BE IN PLACE ACROSS OUR REGION
WHILE THE UPPER TROUGH AND COLD AIR THROUGH THE OHIO VALLEY REGION
LIFTS OUT ACROSS THE NORTHEAST CONUS. A WARMER AIRMASS WILL
SETTLE IN FOR A FEW DAYS AND A DRY DOWNSLOPE WESTERLY WIND COMPONENT
WILL AID IN THE TEMP WARMUP FOR OUR AREA. HIGH ON THURSDAY SHOULD
AVERAGE IN THE LOW/MID 40S...WITH EVEN WARMER 50S EXPECTED FOR
FRIDAY.
TEMPERATURES ON SATURDAY WILL BE DEPENDENT UPON THE TIMING OF A
STRONG COLD FRONTAL PASSAGE WHICH IS PROGGED TO CROSS OUR CWA DURING
THE AFTN/EVENING. IF TIMING TRENDS FASTER...TEMPS WILL NOT BE AS
WARM AS CURRENT FORECAST ESPECIALLY ACROSS OUR NORTHERN ZONES AND
THERMAL GRADIENT WILL NEED TO BE TIGHTENED. THE 6HR PRESSURE RISES
BEHIND FRONT AVERAGE 11MB AND EXPECT A PERIOD OF STRONG/GUSTY NORTH
WINDS FOLLOWING FROPA AND HAVE RAMPED UP WIND SPEEDS HIGHER THAN
WHAT INIT PROVIDED. MODELS ALSO SUGGEST LOW CLOUDS MOVING IN BEHIND
BOUNDARY AND AS PREVIOUS DISCUSSION MENTIONED...COULD SEE SOME
FLURRIES SATURDAY EVENING/NIGHT IN PRESENCE OF FRONTOGENESIS...AND
IS SOMETHING TO MONITOR.
A 1035MB SURFACE HIGH BUILDS SOUTH ONTO THE PLAINS SUNDAY BEHIND THE
COLD FRONT AND TEMPERATURES WILL DROP BACK BELOW SEASONAL NORMALS
FOR A COUPLE OF DAYS. THE AIRMASS LOOKS TO MODERATE SOME FROM LATE
MONDAY INTO TUESDAY/NEW YEARS EVE DAY AND TEMPS NEAR NORMAL APPEAR
REASONABLE FOR NOW. THIS BEING SAID...A COLD AIRMASS IS NOT THAT FAR
AWAY AS A TROUGH DEEPENS OVER THE HUDSON BAY.
&&
.AVIATION...(FOR THE 06Z KGRI TAF THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1216 AM CST WED DEC 25 2013
CONFIDENCE IS HIGH IN VFR CEILING/VISIBILITY THROUGHOUT THE
PERIOD...WITH ONLY VERY LIMITED AMOUNTS OF MID/HIGH CLOUD
COVER...AND ANY BATCHES OF MVFR HEIGHT LOWER STRATUS EXPECTED TO
REMAIN AT LEAST 60-80 MILES NORTHEAST OF KGRI. THE MAIN
MODIFICATION FROM PREVIOUS TAF ISSUANCE WAS TO INCREASE SURFACE
WIND SPEEDS A BIT DURING THE DAYTIME HOURS. STARTING OFF EARLY
THIS MORNING...AND THEN AGAIN LATER IN THE PERIOD THIS EVENING...A
GENERALLY WESTERLY BREEZE IN THE 6-9KT RANGE WILL PREVAIL.
HOWEVER...FOR SEVERAL HOURS DURING THE DAY...ESPECIALLY CENTERED
BETWEEN 17Z-20Z...NORTHWEST BREEZES WILL INCREASE TO SUSTAINED
LEVELS AROUND 14KT WITH GUST POTENTIAL TO AROUND 23KT.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...PFANNKUCH
LONG TERM...FAY
AVIATION...PFANNKUCH
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1206 PM CST WED DEC 25 2013
.DISCUSSION...
330 AM CST
SYNOPSIS...A COUPLE QUICK SNOW SYSTEMS MOVE ACROSS THE REGION
THROUGH TONIGHT WITH 1 TO 2 INCHES EXPECTED PRIMARILY ALONG AND
NORTH OF I-88. A BRIEF WARM UP IS EXPECTED LATE THIS WEEK BEFORE
TEMPERATURES QUICKLY TUMBLE SUNDAY WITH ANOTHER CHANCE OF SNOW. FOR
EXAMPLE HIGH TEMPS SATURDAY WILL BE IN THE MID 30S TO THE LOW 40S
THEN LOW TEMPS SUNDAY NIGHT WILL VARY FROM -6 TO +8 ACROSS THE CWA.
ADDITIONAL CHANCES OF SNOW ARRIVE EARLY NEXT WEEK...WITH TUESDAYS
SYSTEM LOOKING THE MOST IMPRESSIVE.
TODAY AND TONIGHT...
THE LONGWAVE TROUGH AXIS STRETCHES FROM MINNESOTA THROUGH NEW MEXICO
THIS MORNING WITH A SHORTWAVE TRAVELING A BIT QUICKER THAN THE
LARGER WAVE. THE SHORTWAVE IS OVER EASTERN IOWA AND ASSOCIATED WITH
SOME LIGHT RETURNS ON RADAR ALONG THE IL/IA STATE LINE. GUIDANCE
CONTINUES TO BACK OFF ON HOW MUCH SNOW WILL DEVELOP AHEAD OF THE
SHORTWAVE...BUT DECIDED TO KEEP SNOW GOING IN THE FORECAST. TEMPS
HAVE COME UP TO AROUND 20 DEGREES WITH THE DGZ AT OR NEAR THE
SURFACE. FORCING EXTENDS THROUGH THE DGZ FOR A COUPLE OF HOURS WITH
A SATURATED SOUNDING AT THOSE LAYERS. HOWEVER...GIVEN THE DOWN PLAY
IN GUIDANCE AND HOW SNOW IS STRUGGLING TO DEVELOP NOW...LOWERED
STORM TOTAL SNOW AMOUNTS. WENT FOR AN INCH NORTH OF
I-88...ESPECIALLY ALONG THE IL/WI STATE LINE...WITH AN INCH OR LESS
EXPECTED SOUTH OF THAT.
SOUTH TO SOUTHWEST WINDS GUSTING UP TO 20 KT COULD RESULT IN A
LITTLE BLOWING SNOW...BUT NOT OVERLY CONCERNED SINCE ONLY EXPECTING
AN INCH TODAY. THE SNOW THAT DOES FALL WILL BE VERY DRY WITH RATIOS
IN EXCESS OF 20:1. HIGH TEMPS WILL BE AT FREEZING DOWN SOUTH TO THE
MID 20S ALONG THE WI/IL STATE LINE. HOWEVER...WIND CHILLS WILL MAKE
IT FEEL LIKE SINGLE DIGITS ALONG THE WI/IL STATE LINE TO THE TEENS
DOWN SOUTH.
NEXT UP IS THE LOW CURRENTLY STRETCHING FROM HUDSON BAY THROUGH
NORTHWEST MINNESOTA. THE LOW PASSES OVER ONTARIO THIS AFTERNOON
WITH THE UPPER LEVEL TROUGH AXIS PASSING THROUGH THIS AFTN/EVENING.
EXPECTING ANOTHER BATCH OF SNOW SHOWERS TO FORM AHEAD OF THIS AS
WELL. HAVE SNOW ENTERING NORTH CENTRAL IL THIS AFTN WITH A BAND
SPREADING SOUTH EAST THROUGH THIS EVENING. THE DEPTH OF
MOISTURE IN THE DGZ IS MUCH BETTER WITH THIS SECOND DISTURBANCE AND
COULD SEE A QUICK HALF INCH TO INCH THROUGH THIS EVENING. THE
HIGHEST TOTALS ARE AGAIN EXPECTED ALONG THE IL/WI STATE LINE BECAUSE
THE FORCING STARTS OUT FARTHER NORTH AND DOES NOT MOVE INTO IL UNTIL
THE MOISTURE IS OVER INDIANA AND MICHIGAN.
FOR OVERNIGHT DID NOT MAKE ANY MAJOR CHANGES TO GOING LOW TEMPS.
NOT SURE HOW MUCH OF THE AREA WILL HAVE A FRESH SNOWPACK SO TEMPS
MAY HAVE TO BE LOWERED A BIT BY LATER SHIFTS. COLDER AIR ALOFT
MOVES IN BEHIND THE TROUGH AXIS...LESS THAN -8C AT 925 MB...AND
CLOUDS SHOULD THIN LATE TONIGHT. SO UPPER TEENS DOWN SOUTH TO
SINGLE DIGITS ACROSS NORTH CENTRAL IL IS EXPECTED. OVERNIGHT...MIN
WIND CHILLS WILL BE IN THE SINGLE DIGITS DOWN SOUTH TO AS LOW AS
-10F NORTH OF I-88.
THURSDAY AND FRIDAY...
NORTHWEST FLOW ALOFT IS EXPECTED EARLY THURSDAY BUT ANOTHER TROUGH
AXIS ROLLS THROUGH FRIDAY. AT THE SURFACE HIGH PRESSURE BUILDS
ACROSS THE SOUTHERN U.S. WITH ITS RIDGING PASSING OVER THE REGION
THURSDAY AFTN. KEPT A DRY FORECAST GOING FOR THIS PERIOD.
SOUTHWEST FLOW AND WAA RAISE 925 MB TEMPS TO NEAR 0C BY FRIDAY
MORNING...AND THEN TO AROUND +5 BY SATURDAY MORNING. THEREFORE HAVE
TEMPS INCREASING THROUGH FRIDAY TO AROUND 30 ALONG THE IL/WI STATE
LINE TO NEAR 40 ACROSS THE SOUTHERN PORTION OF THE CWA. OVERNIGHT
LOWS FRIDAY LOOK TO BE IN THE 20S.
SATURDAY AND SUNDAY...
THE NEXT WEAK LOW IS PUSHED SOUTH THROUGH THE CWA SATURDAY EVENING
AND NIGHT WITH THE UPPER LEVEL TROUGH AXIS ROTATING THROUGH SUNDAY
NIGHT. THE WARM UP CONTINUES ON SATURDAY...AND TEMPERATURES MAY
HAVE TO BE RAISED FURTHER SINCE GUIDANCE CONTINUES TO SUGGEST 925MB
TEMPS WILL WARM TO +4 TO +8C SATURDAY AFTERNOON. THAT RELATES TO
MAX TEMPS ON SATURDAY OF IN THE MID 30S TO LOW 40S. NOT EXPECTING
ANY PRECIP UNTIL BEHIND THE LOW AND ITS COLD FRONT/UPPER LEVEL
TROUGH AXIS SUNDAY.
FIRST...TEMPERATURES DROP THROUGH THE DAY ON SUNDAY WITH HIGH TEMPS
BEING MET EARLY SUNDAY MORNING. LOOKING AT TEMPS RANGING FROM
SINGLE DIGITS NEAR RFD TO LOW 20S IN NORTHWEST INDIANA BY EARLY
SUNDAY EVENING. SO EXPECTING ANY PRECIP THAT DOES FORM SHOULD BE
SNOW. TEMPS CONTINUE TO FALL WITH 925MB TEMPS AT -15 TO -20C BY
MONDAY MORNING. THEREFORE LOW TEMPS SUNDAY NIGHT WILL RANGE FROM
THE SINGLE DIGITS TO AROUND -5F. NORTHWEST WINDS AROUND 10 KT WILL
CREATE MIN WIND CHILLS BELOW ZERO SUNDAY NIGHT. THE COLDEST AREA
WILL BE NORTH OF I-88 WHERE WIND CHILLS LOWER THAN -20F ARE
POSSIBLE.
FOR SNOW...THE FORCING AND MOISTURE DO NOT SEEM ALL THAT IMPRESSIVE
AT THIS TIME SO NOT EXPECTING ANY MAJOR ACCUMULATION. GFS COBB
OUTPUT AGREES AS IT IS ONLY SHOWING A FEW TENTHS.
EXTENDED...MONDAY AND TUESDAY...
MONDAY REMAINS COLD AS THE UPPER LEVEL COLD AIR LINGERS
OVERHEAD...BUT WINDS TURN WSW AND BEGIN TO USHER IN WARMER AIR ALOFT
MONDAY NIGHT. HIGH TEMPS ON MONDAY WILL BE IN THE SINGLE DIGITS TO
THE LOWER TEENS AND WIND CHILLS DURING THE DAY BELOW ZERO. MIN WIND
CHILLS MONDAY NIGHT WILL ONCE AGAIN BE BELOW ZERO. HIGH PRESSURE
PASSES OVER MONDAY NIGHT WITH ANOTHER CLIPPER ARRIVES TUESDAY. THIS
SYSTEM LOOKS DARE I SAY VIGOROUS...FOR BEING A WEEK AWAY. GUIDANCE
DIFFERS SLIGHTLY SO ONLY UPPED POPS INTO THE CHANCE RANGE...BUT
LOOKING AT LONG RANGE COBB FOR FUN INDICATES SNOWFALL OF A FEW
INCHES.
JEE
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* UNDER 1500FT CIGS THIS AFTERNOON WITH POSSIBLE TEMPORARY IFR.
* LIGHT ACCUMULATING SNOW MOVING IN LATER THIS AFTERNOON AND EVE.
* SMALL CHANCE FOR LIGHT SNOW/FLURRIES LATE IN THE DAY ON THU.
//DISCUSSION...UPDATED 18Z...
STRATUS OVER THE AREA IS WELL TRAPPED UNDER AN INVERSION THIS
AFTERNOON. THIS WOULD INDICATE THE CONTINUED FLATLINE TREND IN
OBSERVATIONS SHOULD CONTINUE...WITH A CHANCE OF STILL TEMPORARILY
DROPPING TO IFR FOR CHICAGOLAND SITES. AN UPPER LEVEL DISTURBANCE
THAT IS MORE IMPRESSIVE THAN THE ONE EARLY THIS MORNING WILL SWING
OVER NORTHERN IL LATE THIS AFTERNOON THROUGH MID-EVE. IT CURRENTLY
IS PRODUCING AN AREA OF IFR VISBYS ACROSS NORTHERN IA/SOUTHEAST
MN/FAR SOUTHWEST WI. SIMILAR TEMPORARY 1 TO 1 1/2SM VISBYS ARE
EXPECTED IN SNOW ACROSS THE AREA...AS FORCING HOLDS STEADY WITH
THIS FEATURE...AND EVEN SOME INDICATIONS IT INCREASES. CIGS ARE
LIKELY TO BOUNCE AROUND WITHIN THE SNOW...THOUGH PRIMARILY REMAIN
AT OR BELOW 2000 FT. UPPER LEVEL FORCING EASES OUT OF THE REGION
LATE THIS EVE/EARLY OVERNIGHT AND MVFR CIGS ARE EXPECTED TO AS
WELL. THE NEXT IN THE SERIES OF NORTHWEST FLOW CLIPPER SYSTEMS IS
FORECAST TO MOVE OVER THE IL/WI STATE LINE LATE IN THE DAY THU.
WHILE THIS COULD END UP PRODUCING MVFR CIGS AND EVEN LIGHT
SNOW/FLURRIES...ITS TOO SMALL OF A PERTURBATION TO CHASE IN A
POINT FORECAST THIS FAR OUT.
WINDS WILL TURN MORE WNW LATE THIS EVE AS A SURFACE COLD FRONT
MOVES THROUGH. THE WINDS WILL BACK TO THE SSW ONCE AGAIN BY THU
AFTERNOON.
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH IN CIGS REMAINING BELOW 1500 FT THROUGH 22Z. LOW IN WHETHER
IFR WILL OCCUR.
* HIGH IN SNOWFALL OCCURRING...ESPECIALLY 00Z-02Z. MEDIUM IN
VISIBILITY TRENDS.
* LOW IN ANY LIGHT SNOW/FLURRIES LATE ON THU.
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT...MAINLY VFR. POSSIBLE PATCHY MVFR CIGS.
THU THROUGH MON...VFR. SLT CHC -SN ON SUN AS WELL AS MON NIGHT.
TUESDAY...SLT CHC -SN.
MTF/BEACHLER
&&
.MARINE...
302 AM CST
HAZARDOUS WAVES/WINDS WILL FOR THE NEARSHORE WATERS AND MAY ALSO
SEE OCCASIONAL GALE FORCE GUSTS IN THE NEARSHORE WATERS THRU
MIDDAY.
SFC RIDGE CENTERED OVER THE OHIO VALLEY CONTINUES TO DRIFT EAST
TOWARDS THE MIDDLE ATLANTIC REGION...STRETCHING NORTH TO QUEBEC.
MEANWHILE A TROUGH OF LOW PRESSURE OVER THE UPPER MIDWEST WILL
SLIDE NORTHEAST TOWARDS CENTRAL ONTARIO THIS MORNING...THEN SLOWLY
LIFT NORTHEAST ACROSS JAMES BAY BY EARLY THURSDAY MORNING. THE
GRADIENT THAT WAS EXPECTED TO DEVELOP AND PRODUCE THE GALES
DEVELOPED BUT REMAINED WELL NORTH OF THE LAKE ACROSS LAKE
SUPERIOR...HOWEVER SOME REPORTS ACROSS THE FAR NORTHERN PORTION OF
LAKE MICHIGAN INDICATE LOW END GALES. SO GIVEN THE REDUCED
CONFIDENCE IN THE GALES AND LACK OF OBSERVATIONS TO SUPPORT
KEEPING THE GALE WARNING GOING...HAVE OPTED TO CANCEL THE GALE
WARNING EARLY. WILL HOWEVER CONTINUE TO MENTION OCCASIONAL GALE
FORCE GUSTS TO 35 KT THROUGH MID MORNING...THEN THE GRADIENT WILL
CONTINUE TO WEAKEN. WINDS WILL STEADILY SHIFT FROM SOUTHWEST TO
WEST BY LATE THIS AFTERNOON...THEN CONTINUE TO DIMINISH TO AROUND
15 TO 25 KT. HAZARDOUS WINDS AND WAVES WILL PERSIST FOR THE
NEARSHORE WATERS AND CONFIDENCE REMAINS HIGH THAT THE SMALL CRAFT
ADVISORY WILL CONTINUE. IT IS POSSIBLE THAT THE SMALL CRAFT
ADVISORY WILL NEED TO BE EXTENDED FOR THE INDIANA NEARSHORE WATERS
AS WINDS TURN WEST...THIS MAY HELP KEEP ELEVATED WAVES LONGER FOR
THIS FAR SOUTHEAST CORNER OF LAKE MICHIGAN.
THE NEXT WEATHER SYSTEM TO BRING A STRONG GRADIENT TO THE LAKE
WILL ARRIVE SAT...AND LIKELY PRODUCE WINDS TO 30KT. IT IS POSSIBLE
A FEW GUSTS TO GALE FORCE MAY OCCUR SAT.
THEN ANOTHER STRONG RIDGE OF HIGH PRESSURE WILL SLIDE SOUTH FROM
CENTRAL CANADA FOR THE SECOND HALF OF THE WEEKEND AND MAY BRING A
TIGHT GRADIENT TO THE LAKE.
SFC RIDGE OVER THE OHIO VALLEY WILL CONTINUE TO DRIFT EAST
TONIGHT...WITH A TIGHTENING GRADIENT ALONG THE WESTERN EDGE. THIS
TIGHT GRADIENT WILL SLIDE OVER THE LAKE TONIGHT...PRODUCING
SOUTH/SOUTHWEST GALES BETWEEN 35-40KT OVERNIGHT. THE GRADIENT
CONTINUES TO SLIDE EAST WITH THE ARRIVAL OF A CLIPPER LOW
PRESSURE. THIS CLIPPER WILL ALLOW THE WINDS TO BECOME
WESTERLY...AND SHOULD SEE GALES COME TO AN END BY MID-MORNING WED.
HOWEVER THE GRADIENT WILL REMAIN RELATIVELY STRONG AND PRODUCE
WINDS TO 30KT THRU MIDDAY WED BEFORE DIMINISHING TO 15 TO 25 KT BY
WED NIGHT.
THE NEXT WEATHER SYSTEM TO BRING A STRONG GRADIENT TO THE LAKE
WILL ARRIVE SAT...AND LIKELY PRODUCE WINDS TO 30KT. IT IS POSSIBLE
A FEW GUSTS TO GALE FORCE MAY OCCUR SAT.
THEN ANOTHER STRONG RIDGE OF HIGH PRESSURE WILL SLIDE SOUTH FROM
CENTRAL CANADA FOR THE SECOND HALF OF THE WEEKEND AND MAY BRING A
TIGHT GRADIENT TO THE LAKE.
BEACHLER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 10 PM WEDNESDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion
National Weather Service Lincoln IL
1123 AM CST Wed Dec 25 2013
.DISCUSSION...
ISSUED 948 AM CST Wed Dec 25 2013
Initial upper wave currently pushing through central Illinois.
Earlier light snow ahead of this wave is now well off to the west.
However, a faster shortwave, currently diving into northwest Iowa,
has been producing some light snow ahead of it, from central Iowa
to western Wisconsin. Morning models showing the bulk of the snow
with this feature tracking just to our north, but the NAM and RAP
models show potential for perhaps a tenth or two of snow north of
I-74 during the evening hours. Have made some updates to the snow
trends in the forecast, namely to add some low PoP`s in the far
northern CWA this evening. Have also removed most of the flurries
after midnight, as the shortwave should be well east of us by that
point. Temperature forecasts generally on track and only needed
some minor tweaks.
Geelhart
&&
.AVIATION...
ISSUED 1123 AM CST Wed Dec 25 2013
IFR conditions spreading southward over the TAF sites late this
morning behind the earlier upper wave. Surface obs showing IFR
ceilings back into central Iowa, just ahead of another fast moving
wave, before ceilings come back up to around 1500-2000 feet. Some
light snow over Iowa expected to track through the northern third
of Illinois late afternoon/early evening. May see some reduced
visibilities at times at KPIA/KBMI from these snow showers. VFR
conditions should start working their way eastward across the area
overnight.
Geelhart
&&
.PREV DISCUSSION...
ISSUED 209 AM CST Wed Dec 25 2013
No major storm systems are anticipated across central Illinois
over the next week, as a prevailing northwesterly flow pattern
brings periodic flurries/very light snow and bouts of very cold
air.
SHORT TERM...Today through Friday
First weak system embedded within the northwesterly flow is
currently approaching the Mississippi River as an elongated
vorticity max stretching from Wisconsin to the Texas panhandle.
This feature has been shearing/weakening as it tracks eastward,
and with limited moisture to work with, has produced only very
meager amounts of light snow across parts of central and northern
Iowa. Stronger lift and steadier snows have been confined further
north across Minnesota into Wisconsin. Despite models insisting on
precip development further south, have not seen much evidence
upstream over Missouri, so have decided to downplay the snow
chances this morning. Will maintain low chance PoPs along/north of
the I-74 corridor through midday, where a dusting is possible.
Further south, will only mention scattered flurries across the
remainder of the KILX CWA.
Once the initial wave passes, another disturbance currently
dropping into North Dakota will skirt across northern Illinois
this evening. Due to increasing synoptic lift ahead of this
feature, have added flurries to the forecast along/west of the
Illinois River late this afternoon, then everywhere tonight.
Upper pattern will begin to go zonal by the end of the week,
signaling a brief warming trend that will help boost highs well
into the 30s and even the lower 40s south of I-70 by Friday.
LONG TERM...Saturday through Tuesday
Warmest day of the forecast period will be Saturday, as
southwesterly winds ahead of an approaching Arctic cold front
allow temps to reach the 40s across the board. Models have been
consistent in bringing the cold front through central Illinois on
Sunday, with each run suggesting clouds and perhaps a few
snow-showers. Will carry low chance PoPs for snow on Sunday
accordingly. Once front passes, another chunk of very cold air
will arrive early next week as the upper flow pattern returns to
northwesterly. With 850mb temps progged to fall into the -12 to
-14C range, highs will drop back into the teens and lower 20s by
Monday. After that, will have to watch the next approaching
clipper system for late Monday into Tuesday. Latest models are
slower and a bit further north with this system, but still suggest
a period of light snow will be possible across the northern CWA
late Tuesday. Timing of these features this far out is quite
difficult, so will only mention very low chance POPs across the
north at this time.
Barnes
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
Area Forecast Discussion
National Weather Service Lincoln IL
949 AM CST Wed Dec 25 2013
.DISCUSSION...
ISSUED 948 AM CST Wed Dec 25 2013
Initial upper wave currently pushing through central Illinois.
Earlier light snow ahead of this wave is now well off to the west.
However, a faster shortwave, currently diving into northwest Iowa,
has been producing some light snow ahead of it, from central Iowa
to western Wisconsin. Morning models showing the bulk of the snow
with this feature tracking just to our north, but the NAM and RAP
models show potential for perhaps a tenth or two of snow north of
I-74 during the evening hours. Have made some updates to the snow
trends in the forecast, namely to add some low PoP`s in the far
northern CWA this evening. Have also removed most of the flurries
after midnight, as the shortwave should be well east of us by that
point. Temperature forecasts generally on track and only needed
some minor tweaks.
Geelhart
&&
.AVIATION...
ISSUED 556 AM CST Wed Dec 25 2013
MVFR clouds will prevail for the first few hours of this TAF
period as a fast moving clipper produces light snow for a period
of an hour or so. Snow has already ended at PIA, and is just
affecting SPI. Over the next 2 hours, BMI, DEC and CMI will see
the snow move through. IFR clouds are poised to develop 2 hours
after the snow ends, based on observation trends upstream. The NAM
and RAP soundings show IFR conditions could persist into the
afternoon, and possibly until near sunset. MVFR conditions could
develop as mixing increases this afternoon, but we generally held
off the return to MVFR clouds until 22-23z.
Some clearing should develop from west to east this evening, as
the drier air returns to lower levels. Clearing could reach PIA as
early as 01z and progress to CMI by 07z.
Winds will be primarily southwest until this evening when they
shift to the west and increase from around 10-12kt to 14-16kt.
Shimon
&&
.PREV DISCUSSION...
ISSUED 209 AM CST Wed Dec 25 2013
No major storm systems are anticipated across central Illinois
over the next week, as a prevailing northwesterly flow pattern
brings periodic flurries/very light snow and bouts of very cold
air.
SHORT TERM...Today through Friday
First weak system embedded within the northwesterly flow is
currently approaching the Mississippi River as an elongated
vorticity max stretching from Wisconsin to the Texas panhandle.
This feature has been shearing/weakening as it tracks eastward,
and with limited moisture to work with, has produced only very
meager amounts of light snow across parts of central and northern
Iowa. Stronger lift and steadier snows have been confined further
north across Minnesota into Wisconsin. Despite models insisting on
precip development further south, have not seen much evidence
upstream over Missouri, so have decided to downplay the snow
chances this morning. Will maintain low chance PoPs along/north of
the I-74 corridor through midday, where a dusting is possible.
Further south, will only mention scattered flurries across the
remainder of the KILX CWA.
Once the initial wave passes, another disturbance currently
dropping into North Dakota will skirt across northern Illinois
this evening. Due to increasing synoptic lift ahead of this
feature, have added flurries to the forecast along/west of the
Illinois River late this afternoon, then everywhere tonight.
Upper pattern will begin to go zonal by the end of the week,
signaling a brief warming trend that will help boost highs well
into the 30s and even the lower 40s south of I-70 by Friday.
LONG TERM...Saturday through Tuesday
Warmest day of the forecast period will be Saturday, as
southwesterly winds ahead of an approaching Arctic cold front
allow temps to reach the 40s across the board. Models have been
consistent in bringing the cold front through central Illinois on
Sunday, with each run suggesting clouds and perhaps a few
snow-showers. Will carry low chance PoPs for snow on Sunday
accordingly. Once front passes, another chunk of very cold air
will arrive early next week as the upper flow pattern returns to
northwesterly. With 850mb temps progged to fall into the -12 to
-14C range, highs will drop back into the teens and lower 20s by
Monday. After that, will have to watch the next approaching
clipper system for late Monday into Tuesday. Latest models are
slower and a bit further north with this system, but still suggest
a period of light snow will be possible across the northern CWA
late Tuesday. Timing of these features this far out is quite
difficult, so will only mention very low chance POPs across the
north at this time.
Barnes
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
258 PM EST WED DEC 25 2013
.SYNOPSIS...
AFTER A ROUND OF SNOW OVERNIGHT INTO THURSDAY...CONDITIONS SHOULD BE
DRY UNTIL ANOTHER COLD FRONT COMES THROUGH SUNDAY AND MONDAY.
TEMPERATURES WILL RISE TO ABOVE NORMAL VALUES FOR THE WEEKEND.
&&
.NEAR TERM /THROUGH THURSDAY/...
CLOUD SHIELD CONTINUES TO ADVANCE FROM THE WEST THIS
AFTERNOON...SLOWLY OVERRUNNING THE ENTIRE FORECAST AREA. WHILE THE
PREVIOUS FORECAST ANTICIPATED A ROUND OF SNOW LATE TONIGHT INTO
THURSDAY MORNING WITH AN UPPER LEVEL TROUGH...LATEST HIGH-RESOLUTION
MODEL RUNS ARE INDICATING THAT A SECOND ROUND OF SNOW WILL OCCUR
BEFORE THE TROUGH PASSAGE. WHILE THE TROUGH REMAINS OVER MICHIGAN
DURING THE EVENING HOURS...AN UPPER LEVEL SHORTWAVE WILL MOVE IN
FROM THE SOUTHWEST. IN ADDITION...MULTIPLE RUNS OF THE RAP SHOW
FRONTOGENESIS DEVELOPING AT 850MB...AND TO A LESSER EXTENT IN THE
12Z NAM. SEVERAL HIRES MODELS SHOW A BAND OF SNOW DEVELOPING ALONG
THE FRONTOGENESIS BY LATE EVENING ACROSS SOUTHERN OHIO EXTENDING
INTO NORTHWESTERN PENNSYLVANIA. THIS BAND SHOULD SLOWLY MOVE TO THE
EAST DURING THE OVERNIGHT HOURS. OVERNIGHT SNOWFALL TOTALS COULD
REACH AN INCH...WITH ISOLATED TWO INCH AMOUNTS POSSIBLE.
LITTLE CHANGE HAS BEEN MADE TO THE PORTION OF THE FORECAST WITH THE
PASSAGE OF THE UPPER TROUGH. TIMING AND ACCUMULATIONS APPEAR TO BE
SIMILAR TO THAT OF THURSDAY MORNING...WITH GENERAL TOTALS AROUND AN
INCH WITH ANOTHER CHANCE FOR ISOLATED TWO INCH AMOUNTS.
HOWEVER...12Z MODELS HAVE INCLUDED SLIGHT REDUCTIONS IN SNOWFALL
TOTALS. BULK OF PRECIPITATION SHOULD HAVE MOVED EAST OF THE REGION
BY NOON...ALTHOUGH THE TYPICAL UPSLOPE/LAKE EFFECT AREAS SHOULD
EXPECT SCATTERED SNOW SHOWERS TO CONTINUE INTO THE AFTERNOON.
TEMPERATURES SHOULD BE MILD OVERNIGHT...WITH HIGHS A FEW DEGREES
BELOW NORMAL.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
MINIMAL CHANGE WAS NEEDED IN THE SHORT TERM AS MODELS SHOW FAIRLY
DECENT CONTINUITY WITH PREVIOUS RUNS. HIGH PRESSURE WILL BEGIN TO
BUILD IN THURSDAY NIGHT FROM THE SOUTH AND WILL MARK THE BEGINNING
OF A RELATIVELY DRY PERIOD FOR THE FORECAST AREA. WINDS WILL
BECOME WEST SOUTHWEST AS HIGH PRESSURE SHIFTS TO THE SOUTH. THIS
WILL RESULT IN TEMPERATURES WARMING TO SLIGHTLY ABOVE NORMAL AND
CONTINUED DRY CONDITIONS. BASED ON LATEST SOUNDINGS...WE MAY
ACTUALLY SEE A FAIR AMOUNT OF SUNSHINE ON SATURDAY.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
A QUICK WARM UP WILL ENSUE SUNDAY AHEAD OF A FAIRLY STRONG COLD
FRONT. SYSTEM WILL BE MOISTURE STARVED FOR THE MOST PART AND
SCATTERED RAIN AND SNOW SHOWERS LATE DAY SUNDAY WILL CHANGE TO ALL
SNOW SHOWERS FOR SUNDAY NIGHT AS MUCH COLDER AIR ONCE AGAIN SURGES
SOUTH ACROSS THE REGION. EXTENDED CHC POPS FOR SNOW SHOWERS INTO
MONDAY NIGHT ESPECIALLY FOR THE RIDGES. NEXT CLIPPER THEN FLIES
SOUTHEAST IN NORTHWEST FLOW ALOFT FOR TUESDAY...AND THIS IS ANOTHER
SYSTEM THAT WILL HAVE LITTLE MOISTURE TO WORK WITH AND SLGT CHC
POPS CONTINUED. BY MID WEEK SURFACE RIDGE WILL BRING DRY AND COLD
CONDITIONS.
&&
.AVIATION /20Z WEDNESDAY THROUGH MONDAY/...
BREAKS IN THE VFR MID DECK WILL FILL IN BY EARLY EVENING. BAND OF
SNOW WILL DEVELOP OVER SOUTHERN OHIO LATE THIS EVENING AND EXTEND
NORTHEAST INTO NORTHWEST PENNSYLVANIA. CURRENT MVFR VISIBILITIES IN
TAFS WITH THIS BAND MAY BE TOO OPTIMISTIC...WITH IFR VISIBILITIES
CERTAINLY POSSIBLE. AT THIS POINT...IFR VIS WAS HELD OFF IN TAFS
UNTIL A SECOND ROUND OF SNOW ARRIVES WITH AN UPPER LEVEL TROUGH
AROUND SUNRISE ON THURSDAY. SNOW IS EXPECTED TO BE LIGHTER AT
ZZV/MGW AND HAVE ONLY GONE WITH MVFR/VFR VIS AT THOSE TERMINALS.
BY EARLY THURSDAY AFTERNOON MVFR CIGS WILL BE HOLDING ON AT MOST
SITES IN FLURRIES...ALTHOUGH FKL/DUJ MAY CONTINUE TO KEEP IFR CIGS
THROUGH THE REST OF THE AFTERNOON.
.OUTLOOK.../THURSDAY NIGHT THROUGH MONDAY/...
IMPROVEMENT TO VFR IS EXPECTED ONCE AGAIN THURSDAY NIGHT ALTHOUGH
MVFR CIGS MAY LINGER ACROSS THE NORTH. GENERAL VFR FRIDAY THROUGH
SATURDAY. AN APPROACHING COLD FRONT MAY BRING RESTRICTIONS ACROSS
THE NORTH LATE DAY SUNDAY AND MONDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
449 PM EST WED DEC 25 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 446 PM EST WED DEC 25 2013
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW UPR TROF CENTERED
OVER CENTRAL NAMERICA BTWN RDGING OVER THE ERN CONUS EXTENDING INTO
QUEBEC AND A STRONGER MEAN RDG OVER THE W. VERY CHILLY AIR LINGERS
OVER THE UPR LKS WITH H85 TEMPS IN THE -15C TO -20C RANGE. THERE ARE
SEVERAL SHRTWVS OF INTEREST EMBEDDED WITHIN THIS UPR TROF. THE FIRST
IS MOVING INTO WRN UPR MI EARLY THIS AFTN AND ACCOMPANIED BY AN AREA
OF COLDER CLD TOPS SHOWN ON IR STLT IMAGERY. IN CONCERT WITH SOME
DEEPER MSTR TO H5 SHOWN ON THE 12Z INL RAOB...SCT-NMRS -SHSN
IMPACTED MUCH OF THE CWA INTO EARLY THIS AFTN BEFORE LARGER SCALE
FORCING ASSOCIATED WITH THE SHRTWV THAT CAUSED THE SN LAST NGT/THIS
MRNG EXITED THE AREA. BUT LARGER SCALE QVECTOR DVGC HAS WEAKENED
THIS SHRTWV/WARMED CLD TOP TEMPS...DIMINISHING THE SHSN DURING THE
LAST COUPLE OF HRS. IN FACT...THERE HAS BEEN SOME CLRG THIS AFTN. A
SECOND SHRTWV IS DIGGING SSEWD THRU MANITOBA...ACCOMPANIED BY A
120KT H3 JET MAX. YET ANOTHER SHRTWV RIDING OVER THE TOP OF THE WRN
RDG IS PUSHING INTO BRITISH COLUMBIA.
MAIN FCST CONCERNS IN THE SHORT TERM ARE POPS/SN AMNTS/NEED FOR
HEADLINES ASSOCIATED WITH PARADE OF SHRTWS PASSING THRU THE UPR LKS
WITHIN THE PERSISTENT UPR TROF.
TNGT...AS SHRTWV DIGGING SEWD THRU MANITOBA PASSES INTO WI
TNGT...EXPECT A WSHFT TO THE NW TO DRIVE A LO PRES TROF ONSHORE.
ALTHOUGH THE 12Z NAM/GFS SHOW THE SHARPEST DPVA/H7-3 QVECTOR CNVGC
PASSING TO THE SW OF THE CWA CLOSER TO THE ACCOMPANYING H3 JET
CORE...NAM FCST SDNGS SHOW INVRN BASE AT CMX RISING TO NEAR 7K FT
THIS EVNG IN THE PRESENCE OF DEEPER MSTR. WITH VERY COLD LLVL AIR
LINGERING NEAR THE SFC...THE SFC WSHFT FM THE WSW OVER THE INTERIOR
WL NOT BE AS DRAMATIC AS OVER/NEAR LK SUP. THE RESULT WL BE
SHARPENED LAND BREEZE LLVL CNVGC NEAR LK SUP...FIRST OVER THE NW CWA
THIS EVNG AND THEN ALSO OVER THE FAR ERN CWA LATER. SINCE THE
ACCOMPANYING UVV IS CENTERED WITHIN THE DGZ AS SHOWN ON NAM FCST
SDNGS...SN/WATER RATIOS SHOULD BE AS HI AS 25-30:1. RELATIVELY LGT
WINDS NO HIER THAN 10-15 KTS SHOULD RESULT IN MINIMAL FRACTURING OF
THE SN FLAKES. CONSIDERING THE FRBL SN/WATER RATIOS AND POTENTIAL
FOR ENHANCED SN NEAR LAND BREEZE CNVGC ZONES...OPTED TO ISSUE AN LES
ADVY FOR THE KEWEENAW AND ALGER/LUCE COUNTIES FOR MAINLY THE AREAS
NEAR LK SUP E FM GRAND MARAIS TO CRISP POINT. ALSO CONCERNED AT
LEAST NORTHERN ONTONAGON COUNTY COULD SEE SOME HEAVIER SN TNGT...
BUT OPTED NOT TO INCLUDE THAT ZONE IN THE HEADLINE SINCE HEAVIER SN
IS LIKELY TO IMPACT ONLY THE RELATIVELY UNPOPULATED NRN PORTION OF
THIS COUNTY. SINCE THERE HAS BEEN PARTIAL CLRG OVER MUCH OF THE CWA
LATE THIS AFTN...OPTED TO LOWER MIN TEMPS A BIT WITH THE EXPECTATION
TEMPS COULD FALL QUICKLY BEFORE A WSHFT TOWARD THE NW ABV THE
SHALLOW COLD AIR NEAR THE SFC BRINGS IN MORE CLDS. BACKING LLVL FLOW
LATE AHEAD OF APRCHG HI PRES RDG/SHRTWV RDG FOLLOWING THE DEPARTING
DIGGING SHRTWV MAY BRING SOME PARTIAL CLRG/MORE UNMODIFIED ARCTIC
AIR TO THE INTERIOR W NEAR THE WI BORDER AS WELL.
THU...NEXT SHRTWV NOW TOPPING UPR RDG OVER WRN CANADA IS PROGGED TO
DIG SEWD THRU MN IN PERSISTENT NW FLOW ALF...WITH SHARPEST DEEP LYR
QVECTOR CNVGC PASSING TO THE SW OF UPR MI. LLVL WINDS ARE FCST TO
BACK SLOWLY TOWARD THE WSW OVER MAINLY THE WRN CWA THRU THE DAY
AHEAD OF THIS DISTURBANCE...SO LES SHOULD BECOME CONFINED TO MAINLY
THE KEWEENAW. ALTHOUGH SN TOTALS OVER KEWEENAW COUNTY TNGT MAY NOT
BE AS IMPRESSIVE AS IN HOUGHTON COUNTY...THE NRN PORTION OF THE
KEWEENAW WL LIKELY SEE MORE SN ON THU...ESPECIALLY LATER IN THE DAY.
WITH A MORE 300 DEGREE FLOW LINGERING THRU MUCH OF THE DAY TO THE
E...EXPECT THE MOST WDSPRD AND HEAVIER LES TO IMPACT ERN ALGER AND
THE THE N HALF OF LUCE COUNTY. OVER THE SCENTRAL...ARRIVAL OF HI
PRES RDG AHEAD OF THE SHRTWV WL BRING PARTIAL SUNSHINE FILTERED BY
MID/HI CLDS ASSOCIATED WITH THE MSTR STARVED SHRTWV.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 446 PM EST WED DEC 25 2013
THURSDAY NIGHT...WITH PASSAGE OF SFC RIDGE...LINGERING LES WILL END
AS WINDS SHIFT SW/OFFSHORE. EXPECT LES WITH THE STRONGER LOW LEVEL CONV
OVER THE FAR NORTHEAST CWA...PER HIGH RES MODELS...COULD STILL
PRODUCE A FEW MORE INCHES OF SNOW. HOWEVER...THE SNOW OVER THE
KEWEENAW SHOULD GENERALLY BE LIGHT...WITH AN INCH OR LESS.
FRIDAY INTO FRI NIGHT...WAA WILL DOMINATE WITH A TEMPORARY
TRANSITION TOWARD A MORE ZONAL PATTERN. THERE MAY BE PERIOD OF LIGHT
PCPN ASSOCIATED WITH ISENTROPIC LIFT THROUGH THE 850-700 MB FRONTAL
ZONE. THE DEEPEST MOISTURE AND BEST CHANCE FOR SATURATION WITH
MEASURABLE PCPN IS EXPECTED FROM THE KEWEENAW INTO THE NE CWA. THERE
MAY BE ENOUGH OF A WARM LAYER...PER NAM/GFS...FOR SOME LIGHT MIXED
PCPN. HOWEVER GIVEN MODEL DIFFERENCES COMAPRED TO THE COLDER
ECMWF...CONFIDENCE WAS NOT HIGH ENOUGH TO INCLUDE ANY SLEET OR FREEZING
RAIN AT THIS TIME.
SAT THROUGH SAT NIGHT...WARMING WILL CONTINUE AHEAD OF A SHRTWV
TRACKING FROM BC NW TO THE NRN PLAINS. MOST LOCATIONS SHOULD CLIMB
TO NEAR 30. HOWEVER...A COLD FRONT DRIFTING SOUTH ACROSS THE CWA MAY
INFLUENCE MAX TEMPS DEPENING ON HOW QUICKLY IT MOVES N-S THROUGH THE
AREA FROM THE LATE MORNING THROUGH THE AFTERNOON. MODEL DIFFERENCES
REMAIN REGARDING THE STRENGTH/TIMING OF THE SHRTWV AND SFC TROUGH
DEVELOPMENT TO THE SOUTH. AFTER THE ARCTIC COLD FRONT MOVES THROUGH
WITH 850 MB TEMPS DROPPING TO AROUND -18C BY 12Z/SUN...LAKE ENHANCED
TO LES WILL DEVELOP. A PERIOD OF MODERATE TO EVEN HEAVY SNOW MAY BE
POSSIBLE FOR NORTH FLOW FAVORED SNOWBELTS IF THE STRONGER
SHRTWV/TROUGH DEVELOPS.
SUN-WED...AFTER WINDS GRADUALLY BACK ON SUN AS HIGH PRES BUILDS
TOWARD THE AREA...PERSISTENT LES WILL THEN DEVELOP FROM SUN THROUGH
TUE...MOSTLY FOR W TO WNW WIND FAVORED SNOWBELTS...AS ACRTIC AIR
SETTLES OVER THE AREA WITH 850 MB TEMPS TO AROUND -25C. BY WED THERE
IS MORE UNCERTAINTY WITH THE WIND DIRECTION GIVEN THE POTENTIAL FOR
CLIPPER SHRTWVS(ECMWF) THAT MAY BRING BACKING WINDS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1228 PM EST WED DEC 25 2013
CMX...EXPECT PREDOMINANT IFR CONDITIONS HERE WITH A W UPSLOPE FLOW
TO GIVE WAY TO A PERIOD OF LOWER LIFR CONDITIONS TNGT WITH THE
ARRIVAL OF A LO PRES TROF/WSHFT TO MORE WNW. ALTHOUGH CONDITIONS WL
IMPROVE LATER TNGT/THU MRNG FOLLOWING THE EXIT OF THIS TROF...IFR
VSBYS SHOULD PERSIST THRU 18Z THU WITH LK EFFECT -SHSN LINGERING.
IWD...EXPECT MVFR TO VFR CONDITIONS THIS AFTN TO GIVE WAY TO A
PERIOD OF IFR VSBYS TNGT WITH THE APRCH/PASSAGE OF A LO PRES TROF.
FOLLOWING THE EXIT OF THIS TROF LATER TNGT...CONDITIONS WL IMPROVE
TO MVFR AND THEN TO VFR ON THU WITH THE APRCH OF A HI PRES RDG/
BACKING LLVL FLOW.
SAW...EXPECT VFR TO OCNL MVFR CONDITIONS THIS AFTN TO GIVE WAY TO A
PERIOD OF MVFR CIGS TNGT ASSOCIATED WITH A LO PRES TROF PASSAGE. VFR
WX SHOULD THEN FOLLOW LATE TNGT INTO THU WITH A DOWNSLOPE W WIND
FOLLOWING THE TROF.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 446 PM EST WED DEC 25 2013
EXPECT W TO NW WINDS UP TO 25 KTS TONIGHT TO DIMINISH TO UNDER 20
KTS ON THU WITH APPROACH OF A HI PRES RIDGE/WEAKER PRES GRADIENT.
FOLLOWING THE PASSAGE OF AN ARCTIC COLD FRONT...NORTH GALES ARE
POSSIBLE. HEAVY FREEZING SPRAY IS ALSO EXPECTED FROM SATURDAY NIGHT
INTO TUESDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY FROM 1 AM TO 7 PM EST THURSDAY FOR
MIZ006-007.
LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST THURSDAY FOR MIZ001-003.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...JLB
AVIATION...KC
MARINE...KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1228 PM EST WED DEC 25 2013
.UPDATE...
ISSUED AT 1043 AM EST WED DEC 25 2013
CANX GOING WARNING FOR LUCE COUNTY EARLY GIVEN EXIT OF ENHANCED CLD
SHOWN ON IR STLT LOOP AND SHIFT OF HEAVY LES BAND TO THE E INTO
CHIPPEWA COUNTY PER CNDN MONTREAL RIVER RADAR. NEARBY SFC OBS ALSO
SHOW A WSHFT TO THE WSW AT ERY AND NAUBINWAY...CONSISTENT WITH THE
PASSAGE OF THE HEAVIER BAND TO THE E. SOME SCT SHSN WL CONT THRU THE
DAY IN LUCE COUNTY...BUT ANY ADDITIONAL ACCUM SHOULD BE LESS THAN AN
INCH.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 531 AM EST WED DEC 25 2013
PARADE OF SHORTWAVES IN STORE ACROSS UPPER GREAT LAKES FOR NEXT 24
HOURS AS UPR LAKES REMAINS ON PERIFERY OF MEAN TROUGH. LEAD
SHORTWAVE AND MOISTURE ADVECTION HAS RESULTED IN WIDESPREAD SNOW
WEST TO EAST ACROSS UPR MICHIGAN. LIMITED REPORTS BUT SEEMS MOST
SNOW /2-3 INCHES/ OCCURRED IN SCNTRL CWA ON NORTHERN FRINGE OF
BETTER DEEP LAYER Q-VECTOR CONVERGENCE.
OTHER AREA OF HIGHER SNOWFALL IS DUE TO LAKE ENHANCEMENT OFF LK
MICHIGAN OVER FAR EAST CWA...JUST TO EAST OF MANISTIQUE TOWARD
NEWBERRY. MQT AND APX RADARS SHOWED MAIN BAND OF LAKE EFFECT AS
EARLY AS 06Z WITH ECHOES OVER NORTHERN LK MICHIGAN UP TO 10KFT
SUGGESTING HEALTHY BAND OF SNOW. HAVING TO DO A LOT OF INTERPOLATION
AND EXTRAPOLATION IN DETERMINING WHAT IS GOING ON IN THSES AREAS
USING MDOT WEBCAMS AND FREQUENT CALLS TO THE ISQ AND ERY AWOS
/LONG-LINE TRANSMISSION OF MANY AWOS ACROSS THE REGION IS DOWN RIGHT
NOW/. WILL HAVE TO WAIT TO GET REPORTS LATER THIS MORNING...BUT AS
BEST WE CAN TELL SEEMS THE HEAVIEST AND MOST PERSISTENT SNOW HAS
OCCURRED FROM NEAR BLANEY PARK TOWARD MCMILLAN IN SOUTHWEST LUCE
COUNTY. JUST WITHIN LAST HOUR...HEAVY SNOW IS PUSHING TOWARD
NEWBERRY. GEM-REGIONAL AND HRRR PEGGING THINGS PRETTY WELL. BOTH
SHOW THE MAIN CONVERGENCE BAND AND HEAVY SNOW MOVING STEADILY TO
THE EAST THIS MORNING...PROBABLY OUT OF ERY BY 15Z IF NOT SOONER.
LOWERED SNOW AMOUNTS SLIGHTLY OVER SOUTHERN LUCE...BUT OVERALL WILL
KEEP HEADLINES AS IS FOR NOW AS WINDS ALONG LK MICHIGAN SHOWING
GUSTS OVER 30 MPH /PROBABLY REPRESENTATIVE WHAT IS OCCURRING WITHIN
THE SNOW BAND FARTHER INLAND/ WHICH WOULD BE RESULTING IN BLOWING
AND DRIFTING OF THE SNOW. WILL RE-EVALUATE THE HEADLINES TOWARD
DAYBREAK TO SEE IF SOME CHANGES ARE NEEDED.
ELSEWHERE...EXPECT THE WIDESPREAD SNOW TO TAPER OFF BY DAYBREAK.
GUSTY WINDS COULD EASILY BLOW THE FLUFFY SNOW AROUND SO PUT OUT
AN SPS MAINLY EMPHASIZING DIFFICULT TRAVEL IN SOME AREAS THIS
MORNING. LATER TODAY...ANOTHER SHORTWAVE CURRENTLY SLIDING ACROSS
MINNESOTA MAY RESULT IN A CONTINUATION OF SOME LGT SNOW OR FLURRIES
FOR MOST OF THE AREA.
INTO TONIGHT...EMPHASIS FOR LAKE EFFECT SHIFTS TO THE SNOWBELTS OF
WESTERN AND EVENTUALLY FAR NORTHEAST UPR MICHIGAN...MAINLY EAST OF
MUNISING AND TO THE NORTH OF NEWBERRY. LAST SHORTWAVE FAIRLY STRONG
BUT DIRECT IMPACTS MOSTLY STAY TO THE SOUTH OF UPR MICHIGAN AS WAVE
TRACKS FM CNTRL MN ACROSS WI. WAVE MAY ACT TO HOLD TROUGHING IN
PLACE OVER SCNTRL LK SUPERIOR RESULTING IN MAINLY WSW WINDS OVER
MUCH OF THE LAND AREAS AND NW WINDS OVER LK SUPERIOR. FOR THIS
REASON...LEANED TOWARD NCEP WRF-ARW/NMM IDEA OF CONVERGENCE BAND
TRYING TO GET GOING OVER THE KEWEENAW TOWARD EASTERN ALGER COUNTY
AFTER LATE EVENING. SOUNDINGS FOR TONIGHT SHOW DRYING AND SUBSIDENCE
ABOVE H8 BUT BULK OF LAKE EFFECT CONVECTIVE LAYER IS WELL WITHIN THE
DGZ RESULTING IN SLR/S SOLIDLY OVER 20:1 AND MAYBE PUSHING TOWARD
30:1. IF CONVERGENCE IS STRONGER...MAY SEE ADVY LEVEL SNOW AMOUNTS
FOR PORTIONS OF KEWEENAW AND PERHAPS AS FAR SOUTH AS HIGHER TERRAIN
OF NORTHERN ONTONAGON COUNTY...INCLUDING WHITE PINE AND ROCKLAND.
SINCE IT WILL BE VERY FLUFFY SNOW AND WINDS/BLSN WILL NOT BE TOO
MUCH OF A FACTOR AND SINCE SOME PLACES IN KEWEENAW ARE WELL OVER 100
INCHES ALREADY FOR SEASON...EVENT DOES NOT APPEAR TO SUPPORT THE
NEED FOR ADVY AS IT STANDS NOW. DAYSHIFT CAN RE-EVALUATE BUT DID NOT
ISSUE AT THIS TIME. HEAVIER LAKE EFFECT WILL ALSO AFFECT THE
SNOWBELTS OF THE NORTHEAST CWA WITH MOST SNOW NOT OCCURRING UNTIL
WELL AFTER MIDNIGHT ONCE WINDS SHIFT MORE WNW. INLAND FROM THE LAKE
EFFECT ISSUES...SKIES MAY TRY TO CLEAR OUT IF THE WINDS ARE MORE WSW
THAN WNW. IF THIS OCCURS...TEMPS OVER INLAND WEST AND CNTRL AND
MAYBE EVEN EASTERN CWA COULD FALL WELL BELOW ZERO.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 531 AM EST WED DEC 25 2013
WARMING WILL OCCUR LATE THIS WEEK AS FLOW BRIEFLY BECOMES ZONAL
ACROSS THE NRN CONUS. HOWEVER...OVER THE NEXT 7 DAYS...THE CURRENT
RATHER DISORGANIZED POLAR VORTEX LOCATED WELL N IN NRN CANADA
WILL REORGANIZE/EXPAND AND DROP S TO THE VCNTY OF HUDSON BAY. AS A
RESULT...ARCTIC AIR WILL AGAIN SPREAD S INTO THE UPPER GREAT LAKES
NEXT WEEK...AND THERE MAY BE A COUPLE OF SHOTS OF BITTER COLD AIR.
PATTERN DOES NOT LOOK FAVORABLE FOR MUCH IN THE WAY OF WIDESPREAD
SYNOPTIC SNOWFALL OVER THE NEXT 7 DAYS. NEXT WEEK...LES WILL BE THE
MAIN PCPN CONCERN...MOSTLY FOR SNOWBELTS FAVORED BY W TO NW WINDS.
BEGINNING THU...WNW FLOW LES WILL GRADUALLY DIMINISH AS WEAK SFC
HIGH PRES RIDGE MOVES FROM THE UPPER MISSISSIPPI VALLEY TOWARD THE
UPPER LAKES. DGZ OCCUPIES A GOOD PORTION OF THE CONVECTIVE LAYER...
SO MIGHT BE ABLE TO FLUFF UP SEVERAL INCHES OF SNOW ACCUMULATION
THU. BEST ACCUMULATIONS SHOULD OCCUR IN FAR NRN ONTONAGON/CNTRL
HOUGHTON COUNTIES DUE TO CONVERGENT WRLY FLOW INTO THAT AREA AND
ALSO ERN ALGER/NRN LUCE COUNTIES WHERE MODELS DEPICT RATHER STRONG
LOW-LEVEL CONVERGENCE. ADVY TYPE HEADLINE MAY BE REQUIRED FOR THE
LATTER AREA.
WITH PASSAGE OF SFC HIGH PRES RIDGE THU NIGHT...LINGERING LES WILL
END AS WINDS SHIFT SW/OFFSHORE. FAVORED THE LOWER SIDE OF GUIDANCE
FOR MIN TEMPS WITH AT LEAST A PERIOD OF LIGHT WINDS AND PARTLY
CLOUDY SKIES IN MOST AREAS.
WAA PATTERN WILL BE IN FULL SWING FRI AS PACIFIC AIR SPREADS OUT
ACROSS THE NRN PLAINS IN DEVELOPING ZONAL FLOW. MIGHT BE A LITTLE
PCPN ACROSS NRN UPPER MI...BUT BETTER PCPN POTENTIAL WILL BE FARTHER
N WHERE SUFFICIENT LOW-LEVEL MOISTENING IS MORE LIKELY. TEMPS WILL
REACH THE 20S ACROSS THE BOARD.
WARMING WILL CONTINUE SAT AHEAD OF A SHORTWAVE TRACKING FROM
BC/PACIFIC NW TO THE NRN PLAINS. MOST LOCATIONS SHOULD TOP OUT
AROUND 30F. HOWEVER...A COLD FRONT DRIFTING S ACROSS UPPER MI WILL
INFLUENCE MAX TEMPS DEPENDING ON ITS TIMING. UPPER DIVERGENCE
ASSOCIATED WITH RIGHT ENTRANCE OF UPPER JET TO THE N AND NE SHOULD
SUPPORT A RIBBON OF -SN BEHIND THE SOUTHWARD DRIFTING COLD FRONT.
THAT -SN SHOULD BEGIN TO AFFECT NW UPPER MI SAT AFTN. AS COLD FRONT
CONTINUES TO DROP S SAT NIGHT/SUN MORNING...EXPECT MOST OF THE FCST
AREA TO SEE SOME -SN...AIDED BY RIGHT ENTRANCE UPPER DIVERGENCE.
SOME LAKE ENHANCEMENT SEEMS LIKELY FOR MOST IF NOT ALL OF NRN UPPER
MI AS WINDS WILL LIKELY SHIFT N FOR A TIME BEHIND COLD FRONT AND
POTENTIAL WEAK SFC WAVE THAT WILL ALSO BE TRACKING ALONG FRONT.
BEHIND THE COLD FRONT AND WITH THE PASSAGE OF ANOTHER SHORTWAVE
ROTATING THRU THE UPPER LAKES AROUND EXPANDING POLAR VORTEX...MUCH
COLDER AIR WILL DUMP INTO THE UPPER LAKES SAT NIGHT/SUN. THIS WILL
RESULT IN NW FLOW LES TAKING OVER SUN AS 850MB TEMPS PLUMMET INTO
THE LOW/MID -20S C. EXPECT SLOWLY FALLING TEMPS DURING THE DAY SUN.
PERSISTENT LES WILL THEN SET UP MON/TUE...MOSTLY FOR W TO WNW WIND
FAVORED SNOWBELTS...AS ACRTIC AIR SETTLES OVER THE AREA (850MB TEMPS
IN THE MID -20S C). LES WILL THEN CONTINUE THRU THE END OF NEXT WEEK
AS ARCTIC AIR WILL DOMINATE THE UPPER LAKES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1228 PM EST WED DEC 25 2013
CMX...EXPECT PREDOMINANT IFR CONDITIONS HERE WITH A W UPSLOPE FLOW
TO GIVE WAY TO A PERIOD OF LOWER LIFR CONDITIONS TNGT WITH THE
ARRIVAL OF A LO PRES TROF/WSHFT TO MORE WNW. ALTHOUGH CONDITIONS WL
IMPROVE LATER TNGT/THU MRNG FOLLOWING THE EXIT OF THIS TROF...IFR
VSBYS SHOULD PERSIST THRU 18Z THU WITH LK EFFECT -SHSN LINGERING.
IWD...EXPECT MVFR TO VFR CONDITIONS THIS AFTN TO GIVE WAY TO A
PERIOD OF IFR VSBYS TNGT WITH THE APRCH/PASSAGE OF A LO PRES TROF.
FOLLOWING THE EXIT OF THIS TROF LATER TNGT...CONDITIONS WL IMPROVE
TO MVFR AND THEN TO VFR ON THU WITH THE APRCH OF A HI PRES RDG/
BACKING LLVL FLOW.
SAW...EXPECT VFR TO OCNL MVFR CONDITIONS THIS AFTN TO GIVE WAY TO A
PERIOD OF MVFR CIGS TNGT ASSOCIATED WITH A LO PRES TROF PASSAGE. VFR
WX SHOULD THEN FOLLOW LATE TNGT INTO THU WITH A DOWNSLOPE W WIND
FOLLOWING THE TROF.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 531 AM EST WED DEC 25 2013
GALES EARLY TODAY FOR EASTERN PORTIONS OF LK SUPERIOR AS SOUTH
WINDS ARE ENHANCED BY PRESSURE FALLS TO NORTH OF LK SUPERIOR. EXPECT
WINDS TO DIMINISH TO LESS THAN 25 KTS LATER AFTN THROUGH TONIGHT.
WINDS WILL DIMINISH FURTHER TO 10-20KT ACROSS MOST OF LAKE SUPERIOR
THU/THU NIGHT AS A WEAK SFC HIGH PRES RIDGE PASSES. SW WINDS WILL
THEN INCREASE TO 15-25KT FRI AHEAD OF THE NEXT APPROACHING COLD
FRONT. AS THE FRONT DRIFTS S ACROSS THE AREA...WINDS WILL DIMINISH
FRI NIGHT/SAT MORNING. ARCTIC AIR WILL THEN SURGE INTO THE UPPER
LAKES LATE SAT THRU EARLY NEXT WEEK. MAY SEE SOME PERIODS OF GALES
EARLY NEXT WEEK ALONG WITH THE RETURN OF HVY FREEZING SPRAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...KC
SHORT TERM...JLA
LONG TERM...ROLFSON
AVIATION...KC
MARINE...JLA/ROLFSON
AREA FORECAST DISCUSSION...UPDATED
NWS TWIN CITIES/CHANHASSEN MN
1229 PM CST WED DEC 25 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 337 AM CST WED DEC 25 2013
TROUGHING AND CYCLONIC FLOW WILL DOMINATE THE SHORT TERM...WHICH
MEANS LOTS OF CLOUDS AND BOUTS OF LIGHT SNOW WILL DOMINATE THE NEXT
24 HOURS. LOOKING AT WATER VAPOR IMAGERY OVERLAID WITH RAP H5
VORTICITY YOU CAN SEE A COUPLE OF WAVES UPSTREAM IN THE NW FLOW THAT
WILL IMPACT US. THE FIRST IS CURRENTLY OVER ERN NODAK AND ALREADY
HAS SNOW MOVING ACROSS ERN SODAK AND NW MN AND WILL BE ARRIVING IN
THE MPX CWA SHORTLY. THE SECOND WAVE IS UP OVER NRN SASKATCHEWAN AND
WILL BE WORKING ACROSS MN THIS AFTERNOON. THESE UPPER WAVES WILL BE
WORKING WITH AN ELEVATED WARM FRONT IN THE H85-H7 LAYER TO THROW
SEVERAL BOUTS OF LIGHT SNOW OUR DIRECTION THROUGH THE PERIOD. THE
BEST BURST WILL BE THE INITIAL ONE THIS MORNING. THE HEAVIEST SNOW
HAS BEEN ALONG THAT ELEVATED WARM FRONT OVER ERN SODAK OVERNIGHT AND
FOLLOWED THE HRRR FOR BRINGING THIS SNOW DOWN THE MN RIVER THIS
MORNING. HAVE ENOUGH QPF OUT OF IT TO GET 0.5 TO 1 INCH SNOW AMOUNTS
FROM WC MN DOWN THE MN RIVER INTO SE MN. FOR THE REST OF THE
PERIOD...THE PATTERN IN PLACE LEADS TO LOW CONFIDENCE ON WHEN/WHERE
THESE LITTLE BURSTS OF SNOW WILL COME DOWN...SO THERE ARE LOTS OF
SMALL POPS THROUGH 9Z TONIGHT...WHICH IS WHEN THE SREF AND HIRES
MODELS FINALLY SHOW SNOW CHANCES EVACUATING THE MPX CWA...FOR A
SHORT TIME ANYWAYS.
TEMPERATURES WILL BE TRICKY THIS PERIOD AS WELL THANKS TO A SFC WARM
FRONT THAT AT 3AM WAS NEAR A ROSEAU/LONG PRAIRIE/TWIN CITIES/ALBERT
LEA LINE. TEMPERATURES EAST OF THIS BOUNDARY HAVE REMAINED IN THE
SINGLE DIGITS...WITH TEMPERATURES SLOWLY RISING INTO THE TEENS AND
EVEN LOWER 20S BY THE TIME YOU GET TO THE MN/SD BORDER. THE COLD
FRONT WAS ALIGNED FROM A WEAK SFC LOW NEAR GRAND FORKS BACK NW INTO
CENTRAL SASKATCHEWAN. THE WARM SECTOR ACROSS THE DAKOTAS HAS BEEN
QUITE IMPRESSIVE THIS MORNING...WITH SEVERAL LOCATIONS ACROSS THE
CENTRAL DAKOTAS WARMING TO BETWEEN 32 AND 34 DEGREES /ABOUT 35
DEGREES WARMER THAN THIS TIME 24 HOURS AGO!/. THE QUESTION FOR
TODAY...IS HOW MUCH OF THIS WARM SECTOR CAN WE GET INTO THE MPX CWA.
THE CORE OF THE WARMEST AIR LOOKS TO DROP SOUTHWEST OF THE MPX
CWA...BUT WE SHOULD STILL SEE TEMPS RISE INTO THE UPPER 20S ACROSS
WRN MN THIS MORNING...BEFORE THE COLD FRONT ARRIVES THIS AFTERNOON
TO START SENDING TEMPERATURES THE OTHER DIRECTION.
FOR TONIGHT THE TWO VARIABLES TO WATCH ARE WHAT HAPPENS WITH CLOUD
COVER AND WHERE DOES THAT COLD FRONT END UP. AS FOR THE FRONT...MOST
MODELS SHOW THE FRONT BECOMING STATIONARY ACROSS SW MN...WITH
ANOTHER PUNCH OF ARCTIC AIR SLIDING DOWN ACROSS AREAS MAINLY NORTH
OF I-94. THIS WILL KEEP TEMPERATURES TONIGHT IN THE MN RIVER VALLEY
ON SOUTH UP IN THE TEENS...BUT BACK NORTH OF I-94...IF SKIES CAN
STAY SUFFICIENTLY CLEAR...WE COULD SEE MORE WIDESPREAD DOUBLE DIGIT
LOWS BELOW ZERO. IT/S NOT OUT OF THE REAL OF POSSIBILITY TO SEE A
NEARLY A NEARLY 30 DEGREE SPREAD IN LOWS TONIGHT ACROSS THE MPX
CWA...WITH LOWS AROUND 15 ABOVE OUT IN WRN MN AND AROUND 15 BELOW
ALONG THE US-8 CORRIDOR IN WRN WI.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 337 AM CST WED DEC 25 2013
THE FORECAST WARM UP FOR THE LATER HALF OF THE WEEK STILL LOOKS TO
BE ON SCHEDULE. SHOULD SEE MODERATING TEMPERATURES INTO SATURDAY
WITH ANOTHER WAFT OF PACIFIC AIR MOVING THROUGH...AHEAD OF NEXT
ARCTIC COLD FRONT. MODELS TREND ANOTHER SHOT OF SNOW ASSOCIATED
WITH THE INITIAL PACIFIC AIR INTRUSION ON THURSDAY. AT THE
MOMENT...HAVE INCLUDED A SMALL LIKELY POP AREA OVER THE NORTHEAST
CWA. SIGNIFICANT MOISTURE APPEARS TO BE LACKING AND MOST MODELS
HAVING TROUBLE SATURATING AS THE PRECIPITATION BAND MOVES FARTHER
EAST. ANY SNOWFALL SHOULD REMAIN LIGHT FOR THIS SYSTEM.
DO EXPECT SOME LOWER 30S AT LEAST AHEAD OF THE ARCTIC BOUNDARY AS
THAT ARRIVES SATURDAY AFTERNOON. WITH STEEP LOW LEVEL LAPSE
RATES...STRONG WIND GUSTS EXPECTED TO MATERIALIZE. 35 KT WIND
GUSTS LOOK LIKELY AS THE SYSTEM MOVES THROUGH. THE BETTER CHANCE
OF SNOW SHOWERS SHOULD RIDE FARTHER EAST...BUT IF THEY DO COINCIDE
WITH THE STRONGEST WINDS...COULD SEE NEAR BLIZZARD CONDITIONS
DEVELOP OVER THE SOUTHWEST/MINNESOTA RIVER VALLEY REGION SATURDAY
AFTERNOON/EVENING. HAVE CONTINUED TO INCLUDE SOME BLOWING SNOW
OVER THE REGION FOR THIS PERIOD...INTO SUNDAY.
THE NEXT SURGE OF ARCTIC AIR DROPS OVER THE REGION SUNDAY AND
LINGERS THROUGH MUCH OF THE COMING WEEK. NORTHWEST FLOW PATTERN
WILL LEAVE THE REGION IN THE FAVORABLE AREA FOR MORE LIGHT/FLUFFY
SNOW EVENTS. MONDAY NIGHT INTO TUESDAY NIGHT LOOKS LIKE THE NEXT
BEST CHANCE OF SOME LIGHT SNOW. HAVE LOW POPS FOR NOW. WILL HOLD
OFF ON HIGHER POPS FOR NOW...TO GET BETTER TIMING AS WE GET CLOSER
TO THE EVENT. WIND CHILLS WILL ONCE AGAIN BECOME AN ISSUE AS THE
COLD AIR ARRIVES AS WELL. THE 00Z ECMWF SHOWS LITTLE MODERATION IN
TEMPERATURES IN THE LONGER TERM...WHICH WOULD TAKE US INTO THE
FIRST WEEK OF THE NEW YEAR.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1220 PM CST WED DEC 25 2013
CONDITIONS ARE LARGELY IMPROVING ACROSS THE AREA WITH STEADY SNOW
PUSHING EAST THROUGH WISCONSIN. GUSTY WINDS BEHIND A COLD FRONT
HAS LED TO SOME BLOWING SNOW ACROSS WESTERN MN...WITH VSBYS IN THE
MVFR CATEGORY. OTHERWISE...MVFR/VFR CIGS EXPECTED THROUGH TONIGHT.
ANOTHER BATCH OF SNOW WILL SLIDE SOUTHEAST...MAINLY ALONG AND JUST
NORTH OF THE MINNESOTA RIVER LATE THURSDAY MORNING.
KMSP...MVFR CONDITIONS WILL BECOME MAINLY VFR THIS
AFTERNOON...THEN BACK TO MVFR LATE THURSDAY MORNING WITH THE NEXT
ROUND OF SNOW.
/OUTLOOK FOR KMSP/
THU NIGHT...VFR. WINDS S AT 5 KTS.
FRI...VFR. WINDS SW 5-10 KTS.
SAT...VFR. CHC MVFR/-SN LATE. WINDS SW 5-10 KTS BCMG NW 20G30KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR MNZ041-
042-047>049-054>057-064-065-073>075-082-083-091-092.
WI...NONE.
&&
$$
SHORT TERM...MPG
LONG TERM...DWE
AVIATION...BORGHOFF
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1159 AM CST WED DEC 25 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 407 AM CST WED DEC 25 2013
WITH ESSENTIALLY ZERO RISK OF PRECIP THROUGH THE NEXT 24
HOURS...THE MAIN FORECAST ISSUES INVOLVE TEMPS/SKY COVER/AND HOW
BREEZY IT WILL GET TODAY. TEMP-WISE...WHAT WOULD OTHERWISE BE A
FAIRLY STRAIGHTFORWARD SITUATION IS COMPLICATED SOMEWHAT BY SOME
MODELS/GUIDANCE STRUGGLING WITH THE INITIALIZATION OF EXISTING
SNOW COVER.
STARTING OFF EARLY THIS CHRISTMAS MORNING...ALL IS QUIET...AS THE
LATEST 11-3.9 MICRON SATELLITE IMAGERY INDICATES ESSENTIALLY CLEAR
SKIES CWA-WIDE...IN THE WAKE OF LOW STRATUS THAT HAS PUSHED EAST
OF THE AREA...AND A BATCH OF MID LEVEL CLOUDS THAT HAS PUSHED
SOUTH OF THE CWA. WATER VAPOR SATELLITE IMAGERY AND SHORT TERM
MODEL DATA INDICATE A BROAD MID-UPPER TROUGH CENTERED OVER THE
CENTRAL CONUS NORTHWARD INTO SOUTH CENTRAL CANADA...WHILE FARTHER
WEST...A LARGE-SCALE RIDGE IS CENTERED OFF THE CA COAST IN THE
PACIFIC. WITHIN THE LARGE SCALE TROUGH OVER THE LOCAL AREA...THERE
ARE FEW SMALLER SCALE SHORTWAVE TROUGHS OF INTEREST...ONE OF WHICH
IS CURRENTLY ORIENTED SOUTHWEST-NORTHEAST FROM SOUTHWEST KS-
NORTHERN MO...AND IS EXITING THE SOUTHEAST CWA AT THIS TIME.
MEANWHILE...ANOTHER CLIPPER-TYPE NORTHWEST-FLOW SHORTWAVE IS IN
THE PROCESS OF DROPPING SOUTHWARD INTO THE DAKOTAS/MN...WITHIN THE
EXIT REGION OF A STOUT 120+KT NORTHERLY JET STREAK EVIDENT AT 300
MILLIBARS THAT IS CURRENTLY POKING SOUTHWARD INTO MT OUT OF
SASKATCHEWAN. AT THE SURFACE...09Z OBJECTIVE ANALYSIS AND
AUTOMATED OBS REVEAL A FAIRLY UNIFORM FIELD OF WESTERLY BREEZES
GENERALLY 5-10 MPH ACROSS THE CWA...DRIVEN WITHIN A FAIRLY WEAK
PRESSURE GRADIENT BETWEEN A 1029MB HIGH CENTERED OVER THE NEB/CO
BORDER AREA AND EXTENDING SOUTHEAST ACROSS KS...AND A 1015MB LOW
CENTERED OVER NORTHWEST MN ASSOCIATED WITH THE AFOREMENTIONED
CLIPPER. TEMP-WISE EARLY THIS MORNING...AS WESTERLY BREEZES HAVE
BECOME MORE ESTABLISHED MOST PLACES HAVE LARGELY LEVELED OFF THE
NOCTURNAL DROP OR EVEN RISEN SOMEWHAT FROM VALUES EARLIER IN THE
NIGHT...BUT GIVEN THE CLEAR SKIES...SOME LOCALIZED DROPS ARE STILL
LIKELY BEFORE THE NIGHT IS THROUGH. ACTUAL LOWS FOR THE NIGHT
ALREADY HAVE BEEN...OR WILL EVENTUALLY BE...SOMEWHERE BETWEEN
15-21 ACROSS MOST OF THE CWA.
FOR THE DAYTIME HOURS TODAY...THE MAIN STORY IN THE MID-UPPER
LEVELS INVOLVES THE SOUTH-SOUTHEAST PROGRESSION OF THE
AFOREMENTIONED CLIPPER SYSTEM...WHICH WILL MAINLY TAKE AIM ON THE
MN/IA REGION AS THE MAIN VORTICITY MAXIMUM AT 500MB ENDS UP OVER
NORTHERN MN BY 00Z/6PM TODAY. GIVEN THE TRACK OF THIS SYSTEM AND
ITS FORCING FIELDS...ANY LIGHT PRECIP TODAY SHOULD MAINLY FOCUS
ALONG A TRACK FROM EASTERN SD ACROSS SOUTHERN MN/NORTHERN IA...AND
MAYBE AS FAR SOUTHWEST AS EXTREME NORTHEAST NEB. ALONG THESE SAME
LINES...THE VAST MAJORITY OF THE CWA SHOULD SEE NOTHING MORE THAN
LIMITED MID-HIGH CLOUD COVER TODAY...WITH SKIES AVERAGING OUT TO
NO WORSE THAN MOSTLY SUNNY. THAT BEING SAID...MODELS SUCH AS THE
06Z NAM AND TO A GREATER EXTENT THE 08Z RAP 13 SHOW THAT THE
SOUTHWEST EDGES OF WHAT COULD BE A FAIRLY SOLID BATCH OF LOWER
STRATUS COULD COME VERY CLOSE TO INFILTRATING A FEW COUNTIES IN
THE FAR NORTHEAST CWA SUCH AS NANCE/POLK...ALTHOUGH THE VAST
MAJORITY OF THIS CLOUD MASS SHOULD PASS 50+ MILES EAST/NORTHEAST
OF THE CWA. ALTHOUGH THE OFFICIAL FORECAST RUNS WITH THE
ASSUMPTION THAT SKIES BECOME NO WORSE THAN PARTLY CLOUDY FOR A FEW
HOURS IN THESE FAR NORTHEAST AREAS...THIS WILL BARE WATCHING AS
THE RAP 900/850MB RELATIVE HUMIDITY FIELDS ARE CURRENTLY HANDLING
UPSTREAM LOWER CLOUDS OVER NORTH CENTRAL/EASTERN SD PRETTY WELL.
TURNING TO THE SURFACE SITUATION...THE MAIN FEATURE TODAY WILL BE
SEVERAL HOURS OF INCREASED NORTHWEST BREEZES...AS ENHANCED LOWER
LEVEL WINDS MIX DOWN TO THE SURFACE AS MIXING HEIGHTS INCREASE TO
AROUND 875MB. THE PRIMARY PERIOD OF ENHANCED NORTHWEST BREEZES
WILL FOCUS BETWEEN 15Z/9AM TO 22Z/4PM...WITH SUSTAINED SPEEDS
15-20 MPH AND GUSTS AT LEAST 20-25 MPH...AND GENERALLY STRONGEST
ACROSS THE NORTHEAST 1/2 OF THE CWA. ALTHOUGH THIS NORTHWESTERLY
WIND TECHNICALLY RESULTS IN AT LEAST WEAK COLD AIR ADVECTION ABOVE
THE SURFACE EVIDENT AT 850MB...THE COMBINATION OF SUNSHINE AND
DECENT MIXING SHOULD RESULT IN A CONSIDERABLY MILDER
DAY...ESPECIALLY IN THOSE CENTRAL/EASTERN COUNTIES THAT REMAINED
QUITE CLOUDY TUESDAY. AS HAS BEEN TYPICAL LATELY...TEMPERATURE
FIELDS IN MODELS SUCH AS THE NAM12 AND ASSOCIATED GUIDANCE ARE
HEAVILY CONTAMINATED BY OVER-ZEALOUS SNOW COVER INITIALIZATION.
FORTUNATELY...THE HOURLY TEMP FIELD OF THE RAP13 LOOKED QUITE
REASONABLE AND UNCONTAMINATED...AND THUS WAS FOLLOWED VERY CLOSELY
TODAY. THIS RESULTED IN SIMILAR HIGH TEMPS TO PREVIOUS
FORECAST...BUT 1-2 DEGREES WARMER IN MANY CENTRAL/SOUTHERN AREAS.
THE NET RESULT IS A RANGE FROM UPPER 30S NORTH...LOW 40S CENTRAL
AND MID 40S SOUTH...ALTHOUGH A RESPECTABLE 1-3 INCHES OF SNOW
COVER CENTERED OVER MUCH OF FURNAS/GOSPER/HARLAN COUNTIES WILL
LIKELY KEEP THOSE AREAS A BIT COOLER THAN BORDERING
AREAS...GENERALLY UPPER 30S.
TURNING TO THIS EVENING/TONIGHT...A RATHER QUIET AND PRECIP-FREE
FORECAST CONTINUES. IN THE MID/UPPER LEVELS...MODEST HEIGHT RISES
WILL BE EVIDENT AT 500MB OVER THE LOCAL AREAS...IN THE WAKE OF THE
FAIRLY VIGOROUS CLIPPER SYSTEM DEPARTING EASTWARD INTO THE LOWER
GREAT LEGION. MEANWHILE THOUGH...A WEAKER/MORE SUBTLE NORTHWEST-
FLOW DISTURBANCE WILL GRADUALLY APPROACH THE CENTRAL PLAINS FROM
THE NORTHERN ROCKIES...REACHING THE SD/NORTHWEST NEB AREA BY
SUNRISE THURSDAY. LOCALLY...THE ONLY EFFECT OF THIS INCOMING WEAK
WAVE WILL BE A MODEST INCREASE IN MAINLY HIGH LEVEL CLOUDS
ESPECIALLY OVER NORTHERN ZONES...BUT EVEN SO...OVERNIGHT SKIES ARE
FORECAST TO AVERAGE NO WORSE THAN MOSTLY CLEAR ACROSS THE MAJORITY
OF THE CWA. AT THE SURFACE...WEAK PRESSURE FALLS CENTERED OVER THE
DAKOTAS WILL ALLOW LOCAL BREEZES TO TRANSITION FROM NORTHWESTERLY
THIS AFTERNOON TO A WEST-SOUTHWEST DIRECTION AT GENERALLY 5-10 MPH
THROUGH THE OVERNIGHT HOURS. ALTHOUGH THESE WESTERLY BREEZES WILL
INDUCE MODEST WARM AIR ADVECTION ALOFT EVIDENT AT 850MB...THE
FAIRLY LIGHT SPEEDS WILL PROBABLY NOT BE ENOUGH TO OFFSET A DECENT
TEMP DROP UNDER THE MOSTLY CLEAR SKIES. THUS TOOK A MIDDLE-GROUND
APPROACH ON LOW TEMPS...MAKING VERY LITTLE CHANGE FROM PREVIOUS
FORECAST VIA A MULTI-MODEL BLEND...RESULTING IN A FAIRLY UNIFORM
LOW TEMPERATURE FIELD OF 16-20 ACROSS THE CWA. THIS IS GENERALLY
2-4 DEGREES MILDER THAN A BLEND OF 00Z MET/MAV GUIDANCE WHICH
APPEARS TO BE A BIT TOO COLD...BUT IS NOT AS WARM AS RAW 2M TEMPS
PRESENTED BY MODELS SUCH AS THE GFS/ECMWF. AS IS TYPICAL IN THESE
OVERNIGHT WESTERLY WIND REGIMES THOUGH...THERE WILL LIKELY BE
SCATTERED NON-DIURNAL TEMP TENDENCIES ACROSS PARTS OF THE AREA.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 407 AM CST WED DEC 25 2013
THURSDAY THROUGH NEW YEARS EVE DAY/TUESDAY. THE LATTER
PART OF THE WEEK INTO THE FIRST PART OF THE WEEKEND ARE STILL
SHAPING UP TO BE THE NICEST/WARMEST DAYS OF THE EXTENDED TIME
FRAME. A NORTHWEST FLOW PATTERN WILL BE IN PLACE ACROSS OUR REGION
WHILE THE UPPER TROUGH AND COLD AIR THROUGH THE OHIO VALLEY REGION
LIFTS OUT ACROSS THE NORTHEAST CONUS. A WARMER AIRMASS WILL
SETTLE IN FOR A FEW DAYS AND A DRY DOWNSLOPE WESTERLY WIND COMPONENT
WILL AID IN THE TEMP WARMUP FOR OUR AREA. HIGH ON THURSDAY SHOULD
AVERAGE IN THE LOW/MID 40S...WITH EVEN WARMER 50S EXPECTED FOR
FRIDAY.
TEMPERATURES ON SATURDAY WILL BE DEPENDENT UPON THE TIMING OF A
STRONG COLD FRONTAL PASSAGE WHICH IS PROGGED TO CROSS OUR CWA DURING
THE AFTN/EVENING. IF TIMING TRENDS FASTER...TEMPS WILL NOT BE AS
WARM AS CURRENT FORECAST ESPECIALLY ACROSS OUR NORTHERN ZONES AND
THERMAL GRADIENT WILL NEED TO BE TIGHTENED. THE 6HR PRESSURE RISES
BEHIND FRONT AVERAGE 11MB AND EXPECT A PERIOD OF STRONG/GUSTY NORTH
WINDS FOLLOWING FROPA AND HAVE RAMPED UP WIND SPEEDS HIGHER THAN
WHAT INIT PROVIDED. MODELS ALSO SUGGEST LOW CLOUDS MOVING IN BEHIND
BOUNDARY AND AS PREVIOUS DISCUSSION MENTIONED...COULD SEE SOME
FLURRIES SATURDAY EVENING/NIGHT IN PRESENCE OF FRONTOGENESIS...AND
IS SOMETHING TO MONITOR.
A 1035MB SURFACE HIGH BUILDS SOUTH ONTO THE PLAINS SUNDAY BEHIND THE
COLD FRONT AND TEMPERATURES WILL DROP BACK BELOW SEASONAL NORMALS
FOR A COUPLE OF DAYS. THE AIRMASS LOOKS TO MODERATE SOME FROM LATE
MONDAY INTO TUESDAY/NEW YEARS EVE DAY AND TEMPS NEAR NORMAL APPEAR
REASONABLE FOR NOW. THIS BEING SAID...A COLD AIRMASS IS NOT THAT FAR
AWAY AS A TROUGH DEEPENS OVER THE HUDSON BAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1147 AM CST WED DEC 25 2013
CLEAR TO MOSTLY CLEAR SKIES CAN BE EXPECTED THROUGH TONIGHT WITH
PERHAPS INCREASING MID TO HIGH CLOUDS THURSDAY MORNING.
HOWEVER...WILL NEED TO KEEP AN EYE ON A SCATTERED DECK OF MVFR
CLOUDS WILL PASS JUST TO THE NORTHEAST OF KGRI THIS AFTERNOON. THE
WIND WILL BE GUSTY AT TIMES THIS AFTERNOON...BUT WILL QUICKLY DIE
OFF THIS EVENING.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...PFANNKUCH
LONG TERM...FAY
AVIATION...WESELY
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1039 AM CST WED DEC 25 2013
.UPDATE...
MAIN CONCERN IN THE ONGOING TODAY PERIOD IS POPS/WX AS A SWATH OF
LIGHT SNOW TAKES AIM AT THE CWA FROM SOUTHEAST MN AND NORTHERN IA.
FORECAST WAS GENERALLY ON TRACK HOWEVER...DID UPDATE POPS/WX TO
ACCOUNT FOR THE LATEST RADAR TRENDS. THE HRRR DOESNT SEEM TO BE
HANDLING THE SWATH AS WELL COMPARED TO OUR LOCAL OFFICE WRF AND
THE OTHER FLAVORS OF WRF AVAILABLE. THOUGH SAID WRF OUTPUT APPEARS
TO BE A BIT SLOW. SNOW TO LIQUID RATIOS ARE EXPECTED TO BE AROUND
17:1 AT LEAST...SO THIS SHOULD YIELD ADDITIONAL ACCUMULATIONS OF
AROUND AN HALF INCH TO AN INCH MOST PLACES. OTHERWISE...REST OF
THE FORECAST PACKAGE WAS JUST ADJUSTED TO KEEP UP WITH TRENDS.
&&
.AVIATION/18Z TAFS/...
ON AND OFF LIGHT SNOW WILL CONTINUE THROUGH LATE MORNING...WITH
VISIBILITIES GENERALLY RANGING FROM 3 TO 5 MILES. A MORE MODERATE
SNOWFALL WILL MOVE IN WEST TO EAST FROM LATE MORNING AND INTO THE
AFTERNOON...DROPPING A HALF AN INCH TO AN INCH MOST PLACES BY
EARLY EVENING. COULD SEE VISIBILITIES DOWN TO 1 MILE FOR A TIME
GIVEN UPSTREAM OBSERVATIONS.
SNOW WILL EXIT THE EAST THIS EVENING...WITH DRY WEATHER EXPECTED
OVERNIGHT. SHOULD SEE SKIES EVENTUALLY RETURN TO VFR BY LATE
TONIGHT INTO THURSDAY MORNING. YET ANOTHER WEAK SYSTEM COULD
BRING A LITTLE LIGHT SNOW BY LATE THURSDAY AFTERNOON.
&&
.PREV DISCUSSION... /ISSUED 433 AM CST WED DEC 25 2013/
SHORT TERM...
CHRISTMAS DAY AND TONIGHT - FORECAST CONFIDENCE HIGH
IN SPITE OF DECENT FORCING...INTRUSION OF DRY AIR ABOVE 800 MB AND
THROUGH THE DENDRITE GROWTH ZONE LIMITED AMOUNTS OF SNOW FROM
INITIAL WARM ADVECTION BAND BUT SECOND BAND IS INTENSIFYING AS IT
CROSSES EASTERN HALF OF WISCONSIN WITH ISENTROPIC ADIABATIC OMEGA
INCREASING FROM 1.5 MICROBARS/SEC TO BETWEEN 2.5 AND 3.0
MICROBARS/SEC. WILL SEE BETWEEN 1/2 INCH AND 1 INCH OF ADDITIONAL
ACCUMULATION FROM THIS BAND.
A BREAK IN SNOW UNTIL NEXT SHORT WAVE DROPS INTO MN LATE THIS
AFTERNOON... DOWN THROUGH WRN WI THIS EVENING AND ACROSS SRN WI/NRN
IL OVERNIGHT. POTENT WAVE PRODUCING SUB-2 MILE VSBYS IN THE DAKOTAS.
HAVE SPREAD CATEGORICAL POPS ACROSS THE CWA FROM WEST TO EAST FROM
LATE THIS MORNING IN THE FAR WEST THROUGH THE AFTERNOON. LINGERED
POPS IN THE EAST THIS EVENING WITH DIFFERENTIAL CYCLONIC VORTICITY
ADVECTION ACTING ON A COLUMN STILL MOIST UP THROUGH DENDRITE GROWTH
ZONE UNTIL AROUND 03Z.
HIGH TEMPERATURES IN THE LOWER TO MID 20S TODAY WITH 925MB-850MB
THERMAL RIDGES PASSING THROUGH. TEMPS FALL TONIGHT WITH LOWS IN THE
SINGLE DIGITS BY THURSDAY MORNING WITH 925 MB TEMPS DROPPING INTO
THE TEENS BELOW ZERO BY 12Z.
THURSDAY-FORECAST CONFIDENCE HIGH
DEEP TROUGH MOVES EAST OF AREA WITH SIGNIFICANT 500 MB HEIGHT RISES
ON THE ORDER OF 160 METERS IN THE MORNING OVER SOUTHERN WISCONSIN.
EMBEDDED WITHIN FAST NORTHWEST FLOW WILL BE ANOTHER WEAK SHORT WAVE
TROUGH THAT WILL MOVE ACROSS THE DAKOTAS AND MINNESOTA AND INTO
WISCONSIN BY THE AFTERNOON. GFS AND ECMWF ARE IN PRETTY GOOD
AGREEMENT WITH BAND OF LIGHT SNOW WITH THIS...BUT NAM IS RATHER DRY.
LEANED TOWARD FORMER SOLUTION AND WENT WITH CHANCE POPS.
ALTHOUGH 1000-500 MB THICKNESS VALUES INCREASE ABOUT 100 METERS IN A
24 HOUR PERIOD...THE LOW LEVEL THERMAL FIELD DOESN`T CHANGE MUCH SO
ONLY MINOR MODERATION EXPECTED WITH HIGHS STILL 5 TO 10 DEGREES
BELOW NORMAL.
FRIDAY-FORECAST CONFIDENCE HIGH
MILD SOUTHWEST FLOW REGIME EXPECTED WITH HEIGHTS RISING ANOTHER 70
METERS AND TEMPERATURES CLIMBING TO ABOUT NORMAL FOR LATE DECEMBER.
AIRMASS LOOKS RATHER DRY. TEMPERATURES HOLDING STEADY OR RISING IN
WARM ADVECTION PATTERN WITH SOUTHWEST FLOW AT NIGHT.
LONG TERM...
SATURDAY-FORECAST CONFIDENCE HIGH
UPPER FLOW TILTS FROM WEST-NORTHWEST TO WESTERLY AS A TROUGH DIGS
INTO NORTHERN PLAINS. FRONT STAYS WELL NORTH OF THE AREA DURING THE
DAY ALLOWING MILD AIRMASS TO OVERSPREAD SOUTHERN WISCONSIN. THIS
AIRMASS WILL BE RATHER DRY...LIMITING THE POTENTIAL FOR
PRECIPITATION AND ADVECTION FOG. LOOKS LIKE ABOVE FREEZING HIGHS IN
THE MIDDLE 30S A GOOD BET DESPITE THE DEEP SNOW COVER WITH 850 MB
TEMPS ABOVE +6C.
PARTY IS OVER AT NIGHT AS COLD FRONT SURGES THROUGH ALONG WITH 120
METER 500 MB HEIGHT FALLS. LOOKS LIKE 850 MB TEMPS CRASH ABOUT 15C
OVERNIGHT. POTENTIAL FOR POST FRONTAL FREEZING RAIN GOING OVER TO
SNOW ESPECIALLY NORTH LATER ON.
SUNDAY-FORECAST CONFIDENCE HIGH
STRONG COLD ADVECTION WITH LIKELY RESULT IN FALLING TEMPERATURES
DURING THE DAY FROM THE TEENS INTO THE SINGLE DIGITS WITH A CHANCE
OF LIGHT SNOW CONTINUING ESPECIALLY EAST.
WIND CHILL VALUES CURRENTLY FORECAST TO DROP INTO -20 TO -30 RANGE
SUNDAY NIGHT SO MAY NEED WIND CHILL HEADLINES LATER ON.
MONDAY-FORECAST CONFIDENCE HIGH
HEIGHTS AND THICKNESS JUST KEEP FALLING AS -45C 500 MB COLD CORE
MOVES ACROSS ONTARIO WITH 1000-500 MB THICKNESSES DOWN AROUND 5000
METERS OVER SOUTHERN WISCONSIN. TEMPERATURES START OUT AROUND 10
BELOW ZERO INLAND AND STRUGGLE INTO SINGLE DIGITS ABOVE ZERO DURING
THE DAY WITH WIND CHILLS ONLY ABOUT 10 BELOW ZERO.
WINDS WILL DROP OFF DURING THE AFTERNOON AS THE POLAR HIGH MOVES
OVERHEAD. LOOKS LIKE WELL BELOW ZERO AGAIN AT NIGHT WITH BETTER
RADIATION CONDITIONS WITH LOWS OF 10 TO 15 BELOW OR COLDER IN THE
WIND SHELTERED LOCATIONS.
TUESDAY-FORECAST CONFIDENCE MEDIUM
ALTHOUGH GFS IS ABOUT 6 HOURS FASTER AS IS TYPICAL VERSUS
ECMWF...BOTH MODELS BRING A RATHER SIGNIFICANT ALBERTA CLIPPER
ACROSS IOWA INTO NORTHERN ILLINOIS. VERY COLD AIRMASS AND POTENTIAL
LAKE ENHANCEMENT SITUATION WITH ECMWF SHOWING ABOUT A THIRD OF AN
INCH OF LIQUID. SO THIS COULD END UP BEING AN ADVISORY TYPE SNOW
EVENT.
--SPECIAL NOTE ABOUT DAYS 8 TO 11--
ALTHOUGH BEYOND THE FORECAST PERIOD...THE 00Z ECMWF HAS MASSIVE
HEIGHT FALLS IN A HIGH AMPLITUDE PATTERN OVER THE GREAT LAKES LATER
IN THE WEEK. A SIGNIFICANT COLD WAVE ACCOMPANIED BY BITTER WINDS IS
A POSSIBILITY.
AVIATION/12Z TAFS/...
MVFR/BRIEFLY IFR VSBYS WITH LAST OF THE MODERATE SNOW BAND EXPECTED
TO PUSH OUT OVER LAKE MICHIGAN BY 12Z. STRATUS DECK TO THE WEST ALL
THE WAY BACK TO WESTERN MN AND IA LEADS TO PESSIMISTIC SKY FORECAST
WITH MVFR CIGS EXPECTED THROUGH THE DAY. CURRENT TIMING OF SNOW WITH
NEXT WAVE BRINGS MVFR/BRIEF IFR VSBYS TO KMSN BETWEEN 17Z AND
18Z...KUES AROUND 19Z AND TO KMKE AND KENW BETWEEN 1930Z AND 20Z.
LOOKING AT A 3-4 HOUR PERIOD OF STEADY LIGHT...TO AT TIMES
MODERATE...SNOW WITH UP TO ANOTHER INCH OF SNOW BY EVENING IN SOME
LOCATIONS. LINGERING LIGHT SNOW UNTIL 03Z AT EASTERN TAF SITES.
MARINE...
WILL KEEP CURRENT END TIME OF SMALL CRAFT ADVISORY AT 00Z AS
APPROACHING TROUGH WILL LOWER SOUTHWEST WINDS THIS
AFTERNOON...THEN BACK WINDS TO THE WEST WITH TROUGH PASSAGE EARLY
THIS EVENING AND FURTHER EASE TO 10 TO 15 KNOTS. WAVES WILL SLOWLY
SUBSIDE DURING THE DAY WITH THE DEVELOPING OFFSHORE FETCH AND
LOWERING WIND SPEEDS. WINDS AND WAVES STILL LOOK TO BE BELOW
CRITERIA BY EARLY THIS EVENING.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 6 PM CST THIS EVENING FOR LMZ643>646.
&&
$$
UPDATE...ET/DDV
TODAY/TONIGHT AND AVIATION/MARINE...REM
THURSDAY THROUGH TUESDAY...CRAVEN