Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 12/31/14
AREA FORECAST DISCUSSION
NWS RENO NV
242 PM PST MON DEC 29 2014
.SYNOPSIS...
A STRONG COLD FRONT WILL PUSH THROUGH THE AREA TONIGHT. SNOWFALL
IS POSSIBLE WITH POTENTIAL TRAVEL IMPACTS FOR THE TUESDAY MORNING
COMMUTE ALONG THE HIGHWAY 395 CORRIDOR. STRONG WINDS ARE EXPECTED
TO PRODUCE ROUGH CONDITIONS ON AREA LAKES ALONG WITH POSSIBLE
AREAS OF BLOWING SNOW. TEMPERATURES WILL BE BITTER COLD WITH WIND
CHILLS IN THE SINGLE DIGITS AND NEGATIVE VALUES HEADING INTO THE
NEW YEAR. A MILDER PATTERN WILL RETURN FOR THE WEEKEND.
&&
.SHORT TERM...TONIGHT THROUGH TUESDAY NIGHT
VISIBLE SATELLITE IMAGERY SHOWING A COLD UPPER LOW ACROSS THE
PACIFIC NORTHWEST WITH COOLING IR COLD TOPS ALONG A STRONG COLD
FRONT OVER SOUTHERN OREGON. THIS FRONT WILL QUICKLY DRIVE SOUTH
THROUGH NORTHERN NEVADA TONIGHT INTO TUESDAY MORNING PROVIDING THE
POTENTIAL FOR A FEW INCHES OF SNOWFALL AND BITTER COLD HEADING INTO
THE NEW YEAR.
HI-RES MESOSCALE AND GLOBAL MODELS ARE BEGINNING TO CLUE INTO THE
FORMATION OF BANDED SNOWFALL CREATED BY STRONG LOW LEVEL
FRONTOGENESIS AND MOISTURE IN A REGION OF FAVORABLE MICROPHYSICS FOR
ICE CRYSTAL GROWTH. THESE COLD TEMPERATURES WILL MAKE FOR LIGHT
AND FLUFFY SNOW. SOME DISAGREEMENT ON TIMING BUT LARGELY LOOKING
FOR SNOWFALL IN THE RENO/CARSON CITY REGION AS EARLY 8PM BUT THE
MOST FAVORABLE WINDOW LOOKS TO BE BETWEEN 10PM-4AM. A WINTER
WEATHER ADVISORY HAS BEEN POSTED FOR THE SIERRA FRONT WHICH
INCLUDES THE HWY 395 CORRIDOR SOUTH THROUGH MINDEN AND
GARDNERVILLE. THE ADVISORY ALSO COVERS PORTIONS OF WESTERN MINERAL
AND SOUTHERN LYON COUNTY. GENERALLY LOOKING FOR SNOWFALL IN THE
1-2" RANGE FROM RENO TO CARSON CITY WITH HIGHER AMOUNTS SOUTH
WHERE UPSLOPE FORCING WILL ADD ADDITIONAL LIFT. LOCATIONS ALONG
THE EASTERN SLOPES OF THE CARSON RANGE, EASTERN ALPINE CO,
NORTHERN MONO COUNTY COULD SEE MORE IN THE 2-4" RANGE. SLIDERS ARE
NOTORIOUSLY DIFFICULT SYSTEMS TO FORECAST SO WILL PUT FORECAST
CONFIDENCE IN SNOW AMOUNTS IN THE MEDIUM CATEGORY.
THE OTHER IMPACTS WITH THIS SYSTEM WILL BE SOME GUSTY CONDITIONS
BEHIND THE FRONT AS A STRONG PRESSURE GRADIENT DEVELOPS ACROSS
WESTERN NEVADA AND THE SIERRA. EXPECTING TO SEE SUSTAINED WINDS IN
THE 15-25 MPH RANGE WITH GUSTS UP TO 40-45 MPH OUT OF THE EAST WHICH
PUTS THIS JUST BELOW ADVISORY CRITERIA ACROSS WESTERN NEVADA. HAVE
HOWEVER POSTED A LAKE WIND ADVISORY FOR PYRAMID LAKE AND A WIND
ADVISORY ACROSS THE TAHOE BASIN. EXPECTING HAZARDOUS BOATING
CONDITIONS ON AREA LAKES WITH GUSTS NEAR 45 MPH EXPECTED IN THE
TAHOE BASIN WITH HIGHEST WAVES ALONG THE ATYPICAL WESTERN SHORES.
WINDS WILL SHARPLY INCREASE IN ELEVATION WITH VERY STRONG WINDS
EXPECTED MAINLY ABOVE 8,500 FEET WHERE GUSTS BETWEEN 80-100+ MPH ARE
POSSIBLE. THIS MAY ALSO POSE THE RISK FOR TREE FALLS ACROSS THE
TAHOE BASIN PARTICULARLY FOR TREES WEAKENED FROM THE PAST WIND
EVENT. THE SAME STRONG WINDS HOLD TRUE ACROSS HIGH TERRAIN THROUGH
MONO COUNTY BUT THE STRONGEST WINDS WILL REMAIN OVER THE CREST AND
ALONG THE WESTERN SLOPES OF THE SIERRA WHERE VERY STRONG DOWNSLOPE
WINDS LOOK FAVORABLE.
OTHERWISE, LOOKING FOR SNOW SHOWERS TO LINGER THROUGH TUESDAY
AFTERNOON ESPECIALLY ACROSS ALPINE AND MONO COUNTY WHERE UPSLOPE
FORCING SETS UP. AN INCH OR TWO IS POSSIBLE ACROSS THE TAHOE BASIN
AND MONO COUNTY OUTSIDE OF AREAS OF LAKE ENHANCED SNOWFALL. STRONG
WINDS MAY ALSO PRODUCE AREAS OF BLOWING SNOW AND REDUCED VISIBILITY.
FUENTES
.(WEDNESDAY AND THURSDAY)..
MAIN CHANGE TO THE WEDNESDAY-THURSDAY TIME FRAME WAS LOWERING MAX
AND MIN TEMPS BY A FEW DEGREES EACH, WITH THE INCREASED
EXPECTATION OF ACCUMULATING SNOW WITH THE UPPER LOW PASSING
THROUGH TONIGHT AND TUESDAY. THE PRESENCE OF SNOW COVER WILL
STRENGTHEN THE VALLEY INVERSION FURTHER AND KEEP HIGHS ONLY IN THE
LOWER-MID 20S WEDNESDAY. STRONG NE-E WINDS WILL CONTINUE OVER THE
SIERRA RIDGES WITH GUSTS 75-85 MPH, WHILE SURFACE WIND GUSTS WILL
GENERALLY RANGE FROM 25-35 MPH EXCEPT NEAR 40 MPH AROUND TAHOE
WEDNESDAY MORNING. THESE WINDS WILL DECREASE LATER IN THE DAY AS
THE UPPER LOW MOVES FROM SOUTHEAST CA TO ARIZONA.
NEW YEARS EVE WILL BE QUITE COLD WITH TEMPERATURES BY MIDNIGHT
DROPPING TO THE LOWER TEENS FOR RENO-CARSON CITY AND SINGLE DIGITS
AROUND TAHOE. ALTHOUGH WINDS WILL BE DECREASING, WIND CHILLS COULD
STILL BE NEAR ZERO FOR WESTERN NV AND -10 DEGREES IN THE TAHOE BASIN
FOR THE FIRST COUPLE HOURS OF 2015. THE EARLY MORNING LOWS FOR NEW
YEARS DAY ARE LIKELY TO BE AROUND 5 DEGREES FOR URBAN AREAS OF
WESTERN NV, AND BELOW ZERO AWAY FROM THE MAIN CITIES AND IN THE
SIERRA VALLEYS.
ON THURSDAY, THE CORE OF THE COLD AIR MASS WILL MOVE AWAY FROM
WESTERN NV BUT WITH INVERSION STILL IN PLACE, HIGHS ARE LIKELY TO
REMAIN BELOW FREEZING. LIGHTER WINDS ARE EXPECTED WITH DRY
CONDITIONS PREVAILING THROUGH THE FIRST DAY OF 2015. MJD
.LONG TERM (FRIDAY-MONDAY)...
THE MOTTO FOR THE LONG TERM WILL BE "WELCOME TO INVERSION CITY".
GUIDANCE CONSENSUS SHOWS RIDGING JUST OFF THE WEST COAST THROUGH THE
WEEKEND WHICH YIELDS WARMING TEMPERATURES AT 700MB. COUPLED WITH A
SURFACE HIGH OVER THE INTERMOUNTAIN WEST THIS RESULTS IN AN
INVERSION PATTERN FOR THE VALLEYS OF WESTERN NV AND NORTHEAST CA,
WITH LIGHT WINDS, LIMITED MIXING, AND POTENTIAL AIR POLLUTION
BUILDUPS. TEMPERATURES IN VALLEYS WILL WARM EACH DAY BUT AT A MUCH
SLOWER RATE COMPARED TO THE MOUNTAINS. IF WE GET SUFFICIENT SNOWFALL
TONIGHT THEN THOSE INVERSIONS COULD BE STRONGER WITH POTENTIAL FOR
SPOTS OF FREEZING FOG IN NORMALLY PRONE AREAS.
UNFORTUNATELY I`M REALLY NOT SEEING MEANINGFUL STORM POTENTIAL
THROUGH AT LEAST MONDAY AS THE RIDGE BLOCKS PACIFIC STORMS FROM
IMPACTING CA/NV. THERE ARE SOME SIGNS OF THE RIDGE BREAKING DOWN OR
BEING UNDERCUT MID/LATE NEXT WEEK ALLOWING AN INCREASED CHANCE OF
ATMOSPHERIC RIVERS LANDFALLING ON THE WEST COAST. BUT OF COURSE
PREDICTABILITY OF THESE PATTERN CHANGES 7-10 DAYS OUT IS QUITE
LIMITED. CS
&&
.AVIATION...
FORECAST CONFIDENCE IN TODAY`S TAFS IS MEDIUM, WITH UNCERTAINTIES IN
TIMING AND INTENSITY OF TONIGHT`S BAND OF SNOW. THESE KIND OF SLIDER
STORMS ARE A CHALLENGE TO PREDICT SO SNOWFALL POTENTIAL REMAINS ONLY
MEDIUM CONFIDENCE AS WELL. HIGH RESOLUTION SIMULATIONS (HRRR) ARE
SHOWING A FAST MOVING BAND OF -SN DEVELOPING FROM AAT-LOL AROUND
SUNDOWN AND THEN DROPPING SOUTHWARD INTO RNO/CXP 4-10Z, TRK/TVL/MEV
AROUND 6-12Z, AND AFTER 12Z AT MMH. IN SUCH A STRONGLY FORCED
SITUATION THE HRRR USUALLY DOES REASONABLY WELL SO WE`LL FOLLOW FOR
THE TAFS.
PERIODS OF MVFR/IFR -SN LIKELY AT RNO/CXP/TRK/TVL/MEV TONIGHT
YIELDING UP TO 2 INCHES OF FLUFFY SNOW. THERE`S ABOUT A 20% CHANCE
WE COULD SEE BRIEF PERIODS OF HEAVIER SNOW, 1/2SM VISIBILITY TYPE
STUFF, BUT PREDICTING TIMING ON THAT IS TRICKY. GUSTY N/NE WINDS
WILL RESULTING IN BLOWING SNOW AS WELL. CLOUDS WILL RESULT IN
TERRAIN OBSCURATION TONIGHT THROUGH TOMORROW.
THE POST-FRONTAL NORTHEAST WINDS TUESDAY WILL BE PRONOUNCED AND
GUSTY, WITH A FRESH SUSTAINED 15-25 KTS EAST/NORTHEAST WIND WITH
GUSTS 25-30 KTS. CXP WHICH IS PRONE TO NE FLOW EVENTS, WILL LIKELY
SEE PERIODS OF STRONGER SUSTAINED WINDS. RIDGE LEVEL GUSTS OF 60-70
KTS FORECAST TOMORROW, INCREASING TUESDAY NIGHT INTO WEDNESDAY. DUE
TO THE UNUSUAL NE WIND DIRECTION, THAT WILL LEAD TO TURBULENCE
ESPECIALLY WEST OF ANY MOUNTAINS DUE TO MOUNTAIN WAVE ACTIVITY. CS
&&
.REV WATCHES/WARNINGS/ADVISORIES...
NV...LAKE WIND ADVISORY FROM 7 AM TO 7 PM PST TUESDAY FOR PYRAMID
LAKE IN NVZ004.
WIND ADVISORY FROM 7 AM TUESDAY TO 4 AM PST WEDNESDAY NVZ002.
WINTER WEATHER ADVISORY FROM 10 PM THIS EVENING TO 4 PM PST
TUESDAY NVZ001.
WINTER WEATHER ADVISORY FROM 8 PM THIS EVENING TO 10 AM PST
TUESDAY NVZ003.
CA...WIND ADVISORY FROM 7 AM TUESDAY TO 4 AM PST WEDNESDAY CAZ072.
&&
$$
FOR MORE INFORMATION FROM THE NATIONAL WEATHER SERVICE VISIT...
HTTP://WEATHER.GOV/RENO (ALL LOWER CASE)
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1057 AM MST MON DEC 29 2014
.UPDATE...
ISSUED AT 937 AM MST MON DEC 29 2014
ADDED THE REMAINING ZONES ON THE PLAINS...SOUTHERN EL PASO COUNTY
AND THE UPPER ARKANSAS RIVER VALLEY TO THE ADVISORY. HRRR...RAP
AND NAM CONTINUE TO SHOW A BROAD AREA OF ISENTROPIC UPGLIDE OVER
THE REGION. AS THE DISTURBANCE APPROACHES SOUTHER COLORADO THIS
AFTERNOON...BROAD SOUTH TO EAST FLOW WILL RISE OVER THE DEEPENING
COLD AIR TO CREATE A PROLONGED PERIOD OF LIGHT TO OCCASIONALLY
MODERATE SNOW. NOT SURE HOW FAR SOUTH SNOW WILL REACH IN EASTERN
LAS ANIMAS AND BACA COUNTIES...BUT IT IS LOOKING AS IF THE
NORTHERN PORTION OF THESE ZONES WILL GET SEVERAL INCHES OF SNOW.
UPGLIDE WILL ALSO REACH SOUTHERN EL PASO COUNTY AND CURRENT TRENDS
SUGGEST THE UPGLIDE WILL BE ABLE TO OVERCOME THE DRYING EFFECTS
DUE TO THE DOWNSLOPE NORTHERLY WINDS. UPGLIDE OVER CHAFFEE AND
LAKE COUNTIES WILL ALLOW FOR A FEW INCHES OF SNOW INT HE VALLEY
BOTTOMS...CREATING SOME SLICK ROADS.
CONTEMPLATING WIND CHILL ADVISORY LATER TONIGHT AND TOMORROW
MORNING FOR PORTIONS OF THE PLAINS AND INTERSTATE 25 CORRIDOR.
CURRENT GRIDS HAVE MARGINAL CRITERIA FOR THIS WELL ADVERTISED
COLD SNAP. -PGW--
UPDATE ISSUED AT 520 AM MST MON DEC 29 2014
BASED ON LAST COUPLE OF RUNS OF THE HRRR....WHICH SHOW GREATEST
SNOWFALL POTENTIAL OVER SE PUEBLO COUNTY AND PORTIONS OF THE
PLAINS N OF THE ARKANSAS...HAVE DECIDED TO ADD THESE COUNTIES TO
THE SNOW ADVISORY. HRRR SHOWS QPF MAXES OVER SRN PUEBLO COUNTY
AND PROWERS COUNTY. THIS MATCHES OTHER MODEL TRENDS AS WELL. SRN
EL PASO LOOKS LIKE IT WILL BE LEFT OUT OF THE HEAVIER SNOW
BANDS...SO WILL LEAVE IT OUT OF THE ADVISORY FOR NOW. ROSE
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 312 AM MST MON DEC 29 2014
...FRIGID AIR HEADED OUR WAY ALONG WITH SOME SNOW...
THE COLD FRONT IS NOW PUSHING SWD THROUGH NE CO AND WILL CONTINUE TO
ADVANCE TO THE SOUTH THIS MORNING. THE FRONT SHOULD BE OVER THE
PALMER DVD BY 15Z AND THEN CHARGE SWD ALONG ALL OF OUR ERN PLAINS BY
18Z. SINCE THE PRECIP WILL ACCOMPANY THE FRONT...HAVE PUSHED BACK
TIMING OF POPS A BIT BUT BY 18Z THERE SHOULD BE FAIRLY GOOD COVERAGE
OF SNOW OVER OUR AREA. THE COLD AIR WILL BE DEEP ENOUGH TO SPILL INTO
THE SAN LUIS VALLEY TONIGHT...SO EVERYONE WILL GET A DOSE OF THE
FRIGID CONDITIONS. TEMPS TODAY WILL START OUT IN THE TEENS AND
SINGLE DIGITS...AND HIGH TEMPS WILL BE REALIZED EARLY AS STRONG CAA
WILL BE THE RULE THROUGH TODAY. MAY NOT GET OUT OF THE TEENS OVER
THE NRN I-25 CORRIDOR...AND REST OF THE SE PLAINS WILL ONLY BE IN THE
20S.
MODELS HAVE BEEN EXTREMELY CONSISTENT BOTH IN TIME AND ACROSS THE
BOARD IN TERMS OF EXPECTED QPF FROM THIS EVENT. HIGH SNOW-LIQUID
RATIOS MAY PUSH THINGS A BIT HIGHER THAN FORECAST...BUT IN GENERAL
THE MODEL GUIDANCE IS SHOWING 3 TO 6 INCH TOTALS FOR THE LOWLANDS
AND 6 TO 8 INCH TOTALS FOR THE MOUNTAINS. HAVE ADDED FREMONT COUNTY
AND THE ARKANSAS RIVER CANYON TO OUR SNOW ADVISORIES...ALONG WITH THE
NORTHERN SAN LUIS VALLEY...WHERE THE MODELS HAVE CONSISTENTLY BEEN
SHOWING DECENT SNOW AMOUNTS FOR TONIGHT. ALSO EXTENDED THE CENTRAL
MTS ADVISORY THROUGH TUESDAY MORNING AS ADDITIONAL ACCUMULATIONS
LOOK LIKELY THERE. SNOW AMOUNTS EVERYWHERE LOOK TO BE BORDERLINE
ADVISORY LEVELS. FROM AN IMPACT PERSPECTIVE...IT WILL BE A TWO EDGED
SWORD SINCE THERE WILL STILL BE PLENTY OF HOLIDAY TRAFFIC BUT WITH
THE HIGH SNOW-LIQUID RATIOS AND COLD AIR...ROAD CONDITIONS MAY NOT
BE QUITE AS BAD. GIVEN THE POTENTIAL FOR SLIGHTLY HIGHER SNOW
TOTALS...AN ADVISORY LOOKS LIKE THE BEST COURSE OF ACTION AT THIS
TIME. REMAINING ZONES/AREAS THAT WILL REQUIRE CLOSE ATTENTION ARE
THE UPPER ARKANSAS VALLEY...IF COLD AIR CONTINUES TO PUSH TO THE
WEST THIS EVENING...AND THE HIGHER TERRAIN OF PUEBLO COUNTY OVER SRN
AND WRN PORTIONS OF THE ZONE.
TONIGHT...LIGHT SNOW WILL CONTINUE AND WILL SPREAD OUT EWD TOWARD
THE KS BORDER. AMOUNTS COULD APPROACH LOW-END ADVISORY LEVELS BY TUE
MORNING. H7 TEMPS CONTINUE TO PLUMMET TO NR MINUS 23 DEGREES...WHICH
TYPICALLY ONLY HAPPENS A COUPLE TIMES EACH WINTER. THE ONLY THING
THAT WILL KEEP THE LOWER ARKANSAS VALLEY FROM HITTING LOWS MINUS 20
DEGREES OR LOWER WILL BE THE EXTENSIVE CLOUDS AND LIGHT SNOW. THIS
WILL SERVE TO KEEP US ON THE `WARM` SIDE...ONLY ZERO TO MINUS 10
DEGREES BY EARLY TUE MORNING. THERE WILL BE BORDERLINE WIND-CHILL
ADVISORY READINGS OVER THE MTS...SAN LUIS VALLEY...AND PIKES PEAK
REGION BUT IT LOOKS FAIRLY SPOTTY AT THIS TIME SO WILL HOLD OFF ON
ISSUING ANY WIND CHILL ALERTS. THE COLDEST AIR STILL LOOKS TO BE ON
TUESDAY AND TUE NIGHT. SO...BREAK OUT LOTS OF LAYERS AND PREPARE FOR
THE COLD! ROSE
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 312 AM MST MON DEC 29 2014
...VERY COLD TUESDAY...THEN WHERE DOES THE UPPER LOW GO LATE IN THE
WEEK?...
TUESDAY...
IT WILL BE VERY COLD ACROSS THE REGION. IT APPEARS NOW THAT ALL
AREAS ON THE PLAINS WILL ONLY SEE HIGH TEMPS IN THE POSITIVE
SINGLE DIGITS. AREAS ON THE PALMER DIVIDE MAY SEE A FEW MAX TEMPS
IN THE NEGATIVE SINGLE DIGITS. I SHOULD NOTE THAT MOS IS A FEW
DEGREES COOLER THAN CURRENT GRIDS...HOWEVER SPC PLUME VIEWER
PRODUCTS LEAN MORE TOWARDS CURRENT NDFD TEMPS...AND CURRENT
FORECASTED HIGH TEMPS MATCH UP WITH SURROUNDING WFO/S. IT WILL BE
CLOUDY OVER THE PLAINS TUESDAY AND SNOW IS LIKELY MOST IF NOT ALL
LOWER ELEVATIONS...ESPECIALLY IN THE MORNING. IT APPEARS THE SNOW
THAT FALLS ON THE PLAINS WILL BE LIGHT...WITH ONLY AN INCH OR TWO
OF NEW SNOW POSSIBLE DURING THE DAY TUESDAY. HIGHER AMOUNTS WILL
BE POSSIBLE ON THE EAST SLOPES OF THE S MTNS.
WIND CHILL READINGS TUESDAY WILL BE THE MAIN CONCERN AS I EXPECT
THESE VALUES WILL RANGE BETWEEN -10 AND -20F MOST OF THE DAY.
MTNS AND VALLEYS WILL SEE SOME LIGHT SNOW...ESPECIALLY C MTNS.
ACCUMS SHOULD BE LIGHT. THE ARCTIC AIR WILL LIKELY GET INTO THE
UPPER ARK RVR VALLEY...HOWEVER THE SAN LUIS VALLEY WILL NOT SEE
THE BRUNT OF THE COLD AIR...AND MAX TEMPS IN THE SLV SHOULD BE IN
THE UPPER TEENS.
TUESDAY NIGHT...
VERY COLD TEMPERATURES ARE CERTAIN. HOW COLD IS THE QUESTION. MIN
TEMPS WILL BE DEPENDENT ON HOW MUCH CLOUDINESS (OR LACK THEREOF) WE
HAVE OVER THE REGION. IT WILL ALSO BE DEPENDENT ON SNOW COVER. FOR
NOW THE NDFD MIN TEMPS RANGE BETWEEN -5 TO -15F OVER THE PLAINS.
IF IT CLEARS OUT AND THERE IS WIDESPREAD SNOW COVER...THEN THESE
TEMPS COULD BE 5 TO 10F COLDER THAN CURRENT FORECASTED LOWS.
WEDNESDAY...
WE START TO MODERATE ACROSS THE REGION...ALTHOUGH IT STILL WILL BE
COLD. I DO NOT EXPECT ANY LOCATIONS IN THE CWA TO GET ABOVE FREEZING
THIS DAY. WARMEST TEMPS WILL LIKELY OCCUR IN THE MID ARK RVR VALLEY
(SALIDA TO CANON CITY) WHERE TEMPS WILL GET INTO THE MID 20S. I
EXPECT THE PLAINS WILL PRIMARILY BE IN THE TEENS WITH A 20S JUST
EAST OF THE MTNS. EXCEPT FOR SOME SHOWERS ALONG THE CONTDVD...IT
WILL BE DRY.
THURSDAY INTO THE WEEKEND...
CONCERN TURN TOWARDS THE CLOSED LOW THAT WILL BE N ARIZ THURSDAY
MORNING. LATEST GUIDANCE IS INDICATING A BIT MORE FAVORABLE TRACK
FOR THE SOUTHERN TIER OF THE FCST AREA...ESPECIALLY THE SAN JUANS
FOR LATE WED INTO EARLY FRIDAY. HAVE INCREASED POPS OVER THE SAN
JUAN REGION THU AND FRI...AND HAVE EXTENDED POPS EASTWARD ACROSS THE
S TIER OF THE PLAINS FRIDAY INTO SATURDAY.
OVER THE REMAINDER OF THE REGION...TEMPS WILL MODIFY WITH TEMPS
RETURNING TO SLIGHTLY BELOW NORMAL TEMPERATURES (~40F PLAINS)
/HODANISH
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1049 AM MST MON DEC 29 2014
KCOS AND KPUB...ARCTIC AIR MASS HAS ARRIVED AND WILL STAY OVER THE
REGION THROUGH THE TAF PERIOD AND BEYOND. A DISTURBANCE MOVING
ACROSS SOUTHERN COLORADO WILL RESULT IN ISENTROPIC UPGLIDE THIS
AFTERNOON AND INTO THE EARLY EVENING. ANTICIPATE THIS WILL BE THE
PERIOD OF HEAVIEST SNOW AT THESE TAF SITES. BY MID EVENING...SNOW
INTENSITY WILL DECREASE WITH PERIODS OF LIGHT SNOW FROM THE WEAK
UPSLOPE FLOW. ANTICIPATE IFR CONDITIONS THROUGH THE PERIOD.
KALS...ARCTIC AIR TO THE EAST WILL FILTER INTO THE SAN LUIS VALLEY
LATER IN THE AFTERNOON. TAFS CURRENTLY HAVE MFVR CONDITIONS
DEVELOPING IN THE EARLY EVENING ASSOCIATED WITH THE ARCTIC AIR.
SOME LIGHT SNOW WILL BE POSSIBLE. MVFR CEILINGS WILL CONTINUE
THROUGH THE END OF THE TAF PERIOD AND LIKELY INTO THE AFTERNOON.
--PGW--
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 5 AM MST TUESDAY FOR COZ065-069-
072>080-083-086>089-093>099.
WINTER WEATHER ADVISORY UNTIL 5 AM MST TUESDAY FOR COZ058>063-
081-082-084-085.
&&
$$
UPDATE...PGW
SHORT TERM...ROSE
LONG TERM...HODANISH
AVIATION...PGW
AREA FORECAST DISCUSSION
NWS PUEBLO CO
948 AM MST MON DEC 29 2014
.UPDATE...
ISSUED AT 937 AM MST MON DEC 29 2014
ADDED THE REMAINING ZONES ON THE PLAINS...SOUTHERN EL PASO COUNTY
AND THE UPPER ARKANSAS RIVER VALLEY TO THE ADVISORY. HRRR...RAP
AND NAM CONTINUE TO SHOW A BROAD AREA OF ISENTROPIC UPGLIDE OVER
THE REGION. AS THE DISTURBANCE APPROACHES SOUTHER COLORADO THIS
AFTERNOON...BROAD SOUTH TO EAST FLOW WILL RISE OVER THE DEEPENING
COLD AIR TO CREATE A PROLONGED PERIOD OF LIGHT TO OCCASIONALLY
MODERATE SNOW. NOT SURE HOW FAR SOUTH SNOW WILL REACH IN EASTERN
LAS ANIMAS AND BACA COUNTIES...BUT IT IS LOOKING AS IF THE
NORTHERN PORTION OF THESE ZONES WILL GET SEVERAL INCHES OF SNOW.
UPGLIDE WILL ALSO REACH SOUTHERN EL PASO COUNTY AND CURRENT TRENDS
SUGGEST THE UPGLIDE WILL BE ABLE TO OVERCOME THE DRYING EFFECTS
DUE TO THE DOWNSLOPE NORTHERLY WINDS. UPGLIDE OVER CHAFFEE AND
LAKE COUNTIES WILL ALLOW FOR A FEW INCHES OF SNOW INT HE VALLEY
BOTTOMS...CREATING SOME SLICK ROADS.
CONTEMPLATING WIND CHILL ADVISORY LATER TONIGHT AND TOMORROW
MORNING FOR PORTIONS OF THE PLAINS AND INTERSTATE 25 CORRIDOR.
CURRENT GRIDS HAVE MARGINAL CRITERIA FOR THIS WELL ADVERTISED
COLD SNAP. -PGW--
UPDATE ISSUED AT 520 AM MST MON DEC 29 2014
BASED ON LAST COUPLE OF RUNS OF THE HRRR....WHICH SHOW GREATEST
SNOWFALL POTENTIAL OVER SE PUEBLO COUNTY AND PORTIONS OF THE
PLAINS N OF THE ARKANSAS...HAVE DECIDED TO ADD THESE COUNTIES TO
THE SNOW ADVISORY. HRRR SHOWS QPF MAXES OVER SRN PUEBLO COUNTY
AND PROWERS COUNTY. THIS MATCHES OTHER MODEL TRENDS AS WELL. SRN
EL PASO LOOKS LIKE IT WILL BE LEFT OUT OF THE HEAVIER SNOW
BANDS...SO WILL LEAVE IT OUT OF THE ADVISORY FOR NOW. ROSE
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 312 AM MST MON DEC 29 2014
...FRIGID AIR HEADED OUR WAY ALONG WITH SOME SNOW...
THE COLD FRONT IS NOW PUSHING SWD THROUGH NE CO AND WILL CONTINUE TO
ADVANCE TO THE SOUTH THIS MORNING. THE FRONT SHOULD BE OVER THE
PALMER DVD BY 15Z AND THEN CHARGE SWD ALONG ALL OF OUR ERN PLAINS BY
18Z. SINCE THE PRECIP WILL ACCOMPANY THE FRONT...HAVE PUSHED BACK
TIMING OF POPS A BIT BUT BY 18Z THERE SHOULD BE FAIRLY GOOD COVERAGE
OF SNOW OVER OUR AREA. THE COLD AIR WILL BE DEEP ENOUGH TO SPILL INTO
THE SAN LUIS VALLEY TONIGHT...SO EVERYONE WILL GET A DOSE OF THE
FRIGID CONDITIONS. TEMPS TODAY WILL START OUT IN THE TEENS AND
SINGLE DIGITS...AND HIGH TEMPS WILL BE REALIZED EARLY AS STRONG CAA
WILL BE THE RULE THROUGH TODAY. MAY NOT GET OUT OF THE TEENS OVER
THE NRN I-25 CORRIDOR...AND REST OF THE SE PLAINS WILL ONLY BE IN THE
20S.
MODELS HAVE BEEN EXTREMELY CONSISTENT BOTH IN TIME AND ACROSS THE
BOARD IN TERMS OF EXPECTED QPF FROM THIS EVENT. HIGH SNOW-LIQUID
RATIOS MAY PUSH THINGS A BIT HIGHER THAN FORECAST...BUT IN GENERAL
THE MODEL GUIDANCE IS SHOWING 3 TO 6 INCH TOTALS FOR THE LOWLANDS
AND 6 TO 8 INCH TOTALS FOR THE MOUNTAINS. HAVE ADDED FREMONT COUNTY
AND THE ARKANSAS RIVER CANYON TO OUR SNOW ADVISORIES...ALONG WITH THE
NORTHERN SAN LUIS VALLEY...WHERE THE MODELS HAVE CONSISTENTLY BEEN
SHOWING DECENT SNOW AMOUNTS FOR TONIGHT. ALSO EXTENDED THE CENTRAL
MTS ADVISORY THROUGH TUESDAY MORNING AS ADDITIONAL ACCUMULATIONS
LOOK LIKELY THERE. SNOW AMOUNTS EVERYWHERE LOOK TO BE BORDERLINE
ADVISORY LEVELS. FROM AN IMPACT PERSPECTIVE...IT WILL BE A TWO EDGED
SWORD SINCE THERE WILL STILL BE PLENTY OF HOLIDAY TRAFFIC BUT WITH
THE HIGH SNOW-LIQUID RATIOS AND COLD AIR...ROAD CONDITIONS MAY NOT
BE QUITE AS BAD. GIVEN THE POTENTIAL FOR SLIGHTLY HIGHER SNOW
TOTALS...AN ADVISORY LOOKS LIKE THE BEST COURSE OF ACTION AT THIS
TIME. REMAINING ZONES/AREAS THAT WILL REQUIRE CLOSE ATTENTION ARE
THE UPPER ARKANSAS VALLEY...IF COLD AIR CONTINUES TO PUSH TO THE
WEST THIS EVENING...AND THE HIGHER TERRAIN OF PUEBLO COUNTY OVER SRN
AND WRN PORTIONS OF THE ZONE.
TONIGHT...LIGHT SNOW WILL CONTINUE AND WILL SPREAD OUT EWD TOWARD
THE KS BORDER. AMOUNTS COULD APPROACH LOW-END ADVISORY LEVELS BY TUE
MORNING. H7 TEMPS CONTINUE TO PLUMMET TO NR MINUS 23 DEGREES...WHICH
TYPICALLY ONLY HAPPENS A COUPLE TIMES EACH WINTER. THE ONLY THING
THAT WILL KEEP THE LOWER ARKANSAS VALLEY FROM HITTING LOWS MINUS 20
DEGREES OR LOWER WILL BE THE EXTENSIVE CLOUDS AND LIGHT SNOW. THIS
WILL SERVE TO KEEP US ON THE `WARM` SIDE...ONLY ZERO TO MINUS 10
DEGREES BY EARLY TUE MORNING. THERE WILL BE BORDERLINE WIND-CHILL
ADVISORY READINGS OVER THE MTS...SAN LUIS VALLEY...AND PIKES PEAK
REGION BUT IT LOOKS FAIRLY SPOTTY AT THIS TIME SO WILL HOLD OFF ON
ISSUING ANY WIND CHILL ALERTS. THE COLDEST AIR STILL LOOKS TO BE ON
TUESDAY AND TUE NIGHT. SO...BREAK OUT LOTS OF LAYERS AND PREPARE FOR
THE COLD! ROSE
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 312 AM MST MON DEC 29 2014
...VERY COLD TUESDAY...THEN WHERE DOES THE UPPER LOW GO LATE IN THE
WEEK?...
TUESDAY...
IT WILL BE VERY COLD ACROSS THE REGION. IT APPEARS NOW THAT ALL
AREAS ON THE PLAINS WILL ONLY SEE HIGH TEMPS IN THE POSITIVE
SINGLE DIGITS. AREAS ON THE PALMER DIVIDE MAY SEE A FEW MAX TEMPS
IN THE NEGATIVE SINGLE DIGITS. I SHOULD NOTE THAT MOS IS A FEW
DEGREES COOLER THAN CURRENT GRIDS...HOWEVER SPC PLUME VIEWER
PRODUCTS LEAN MORE TOWARDS CURRENT NDFD TEMPS...AND CURRENT
FORECASTED HIGH TEMPS MATCH UP WITH SURROUNDING WFO/S. IT WILL BE
CLOUDY OVER THE PLAINS TUESDAY AND SNOW IS LIKELY MOST IF NOT ALL
LOWER ELEVATIONS...ESPECIALLY IN THE MORNING. IT APPEARS THE SNOW
THAT FALLS ON THE PLAINS WILL BE LIGHT...WITH ONLY AN INCH OR TWO
OF NEW SNOW POSSIBLE DURING THE DAY TUESDAY. HIGHER AMOUNTS WILL
BE POSSIBLE ON THE EAST SLOPES OF THE S MTNS.
WIND CHILL READINGS TUESDAY WILL BE THE MAIN CONCERN AS I EXPECT
THESE VALUES WILL RANGE BETWEEN -10 AND -20F MOST OF THE DAY.
MTNS AND VALLEYS WILL SEE SOME LIGHT SNOW...ESPECIALLY C MTNS.
ACCUMS SHOULD BE LIGHT. THE ARCTIC AIR WILL LIKELY GET INTO THE
UPPER ARK RVR VALLEY...HOWEVER THE SAN LUIS VALLEY WILL NOT SEE
THE BRUNT OF THE COLD AIR...AND MAX TEMPS IN THE SLV SHOULD BE IN
THE UPPER TEENS.
TUESDAY NIGHT...
VERY COLD TEMPERATURES ARE CERTAIN. HOW COLD IS THE QUESTION. MIN
TEMPS WILL BE DEPENDENT ON HOW MUCH CLOUDINESS (OR LACK THEREOF) WE
HAVE OVER THE REGION. IT WILL ALSO BE DEPENDENT ON SNOW COVER. FOR
NOW THE NDFD MIN TEMPS RANGE BETWEEN -5 TO -15F OVER THE PLAINS.
IF IT CLEARS OUT AND THERE IS WIDESPREAD SNOW COVER...THEN THESE
TEMPS COULD BE 5 TO 10F COLDER THAN CURRENT FORECASTED LOWS.
WEDNESDAY...
WE START TO MODERATE ACROSS THE REGION...ALTHOUGH IT STILL WILL BE
COLD. I DO NOT EXPECT ANY LOCATIONS IN THE CWA TO GET ABOVE FREEZING
THIS DAY. WARMEST TEMPS WILL LIKELY OCCUR IN THE MID ARK RVR VALLEY
(SALIDA TO CANON CITY) WHERE TEMPS WILL GET INTO THE MID 20S. I
EXPECT THE PLAINS WILL PRIMARILY BE IN THE TEENS WITH A 20S JUST
EAST OF THE MTNS. EXCEPT FOR SOME SHOWERS ALONG THE CONTDVD...IT
WILL BE DRY.
THURSDAY INTO THE WEEKEND...
CONCERN TURN TOWARDS THE CLOSED LOW THAT WILL BE N ARIZ THURSDAY
MORNING. LATEST GUIDANCE IS INDICATING A BIT MORE FAVORABLE TRACK
FOR THE SOUTHERN TIER OF THE FCST AREA...ESPECIALLY THE SAN JUANS
FOR LATE WED INTO EARLY FRIDAY. HAVE INCREASED POPS OVER THE SAN
JUAN REGION THU AND FRI...AND HAVE EXTENDED POPS EASTWARD ACROSS THE
S TIER OF THE PLAINS FRIDAY INTO SATURDAY.
OVER THE REMAINDER OF THE REGION...TEMPS WILL MODIFY WITH TEMPS
RETURNING TO SLIGHTLY BELOW NORMAL TEMPERATURES (~40F PLAINS)
/HODANISH
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 312 AM MST MON DEC 29 2014
AN ARCTIC FRONT WILL PUSH SOUTHWARD INTO SE CO BETWEEN 15 AND 18Z
THIS MORNING. THIS WILL LEAD TO A PROLONGED PERIOD OF MVFR TO IFR
CONDITIONS...AND OCCASIONAL LIFR CONDITIONS...THROUGH TUESDAY. KCOS
AND KPUB WILL SEE THESE CONDITIONS DEVELOP FROM 16-18Z AS LIGHT SNOW
BECOMES MORE WIDESPREAD AND PERSISTENT THROUGH THIS AFTERNOON. WINDS
WILL BE MODERATE FROM THE NE DURING THIS PERIOD. KALS WILL SEE
CONDITIONS DETERIORATE A BIT LATER TODAY AS IT WILL TAKE A WHILE FOR
THE COLD AIR TO SPILL OVER INTO THE SAN LUIS VALLEY...BUT SIMILAR
MVFR-IFR CONDITIONS ARE EXPECTED IN THE HIGH VALLEYS OVERNIGHT INTO
TUE MORNING. ROSE
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 5 AM MST TUESDAY FOR COZ065-069-
072>080-083-086>089-093>099.
WINTER WEATHER ADVISORY UNTIL 5 AM MST TUESDAY FOR COZ059-
061>063-085.
WINTER WEATHER ADVISORY UNTIL 5 AM MST TUESDAY FOR COZ058-060-
081-082-084.
&&
$$
UPDATE...PGW
SHORT TERM...ROSE
LONG TERM...HODANISH
AVIATION...ROSE
AREA FORECAST DISCUSSION
NWS PUEBLO CO
524 AM MST MON DEC 29 2014
.UPDATE...
ISSUED AT 520 AM MST MON DEC 29 2014
BASED ON LAST COUPLE OF RUNS OF THE HRRR....WHICH SHOW GREATEST
SNOWFALL POTENTIAL OVER SE PUEBLO COUNTY AND PORTIONS OF THE
PLAINS N OF THE ARKANSAS...HAVE DECIDED TO ADD THESE COUNTIES TO
THE SNOW ADVISORY. HRRR SHOWS QPF MAXES OVER SRN PUEBLO COUNTY
AND PROWERS COUNTY. THIS MATCHES OTHER MODEL TRENDS AS WELL. SRN
EL PASO LOOKS LIKE IT WILL BE LEFT OUT OF THE HEAVIER SNOW
BANDS...SO WILL LEAVE IT OUT OF THE ADVISORY FOR NOW. ROSE
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 312 AM MST MON DEC 29 2014
...FRIGID AIR HEADED OUR WAY ALONG WITH SOME SNOW...
THE COLD FRONT IS NOW PUSHING SWD THROUGH NE CO AND WILL CONTINUE TO
ADVANCE TO THE SOUTH THIS MORNING. THE FRONT SHOULD BE OVER THE
PALMER DVD BY 15Z AND THEN CHARGE SWD ALONG ALL OF OUR ERN PLAINS BY
18Z. SINCE THE PRECIP WILL ACCOMPANY THE FRONT...HAVE PUSHED BACK
TIMING OF POPS A BIT BUT BY 18Z THERE SHOULD BE FAIRLY GOOD COVERAGE
OF SNOW OVER OUR AREA. THE COLD AIR WILL BE DEEP ENOUGH TO SPILL INTO
THE SAN LUIS VALLEY TONIGHT...SO EVERYONE WILL GET A DOSE OF THE
FRIGID CONDITIONS. TEMPS TODAY WILL START OUT IN THE TEENS AND
SINGLE DIGITS...AND HIGH TEMPS WILL BE REALIZED EARLY AS STRONG CAA
WILL BE THE RULE THROUGH TODAY. MAY NOT GET OUT OF THE TEENS OVER
THE NRN I-25 CORRIDOR...AND REST OF THE SE PLAINS WILL ONLY BE IN THE
20S.
MODELS HAVE BEEN EXTREMELY CONSISTENT BOTH IN TIME AND ACROSS THE
BOARD IN TERMS OF EXPECTED QPF FROM THIS EVENT. HIGH SNOW-LIQUID
RATIOS MAY PUSH THINGS A BIT HIGHER THAN FORECAST...BUT IN GENERAL
THE MODEL GUIDANCE IS SHOWING 3 TO 6 INCH TOTALS FOR THE LOWLANDS
AND 6 TO 8 INCH TOTALS FOR THE MOUNTAINS. HAVE ADDED FREMONT COUNTY
AND THE ARKANSAS RIVER CANYON TO OUR SNOW ADVISORIES...ALONG WITH THE
NORTHERN SAN LUIS VALLEY...WHERE THE MODELS HAVE CONSISTENTLY BEEN
SHOWING DECENT SNOW AMOUNTS FOR TONIGHT. ALSO EXTENDED THE CENTRAL
MTS ADVISORY THROUGH TUESDAY MORNING AS ADDITIONAL ACCUMULATIONS
LOOK LIKELY THERE. SNOW AMOUNTS EVERYWHERE LOOK TO BE BORDERLINE
ADVISORY LEVELS. FROM AN IMPACT PERSPECTIVE...IT WILL BE A TWO EDGED
SWORD SINCE THERE WILL STILL BE PLENTY OF HOLIDAY TRAFFIC BUT WITH
THE HIGH SNOW-LIQUID RATIOS AND COLD AIR...ROAD CONDITIONS MAY NOT
BE QUITE AS BAD. GIVEN THE POTENTIAL FOR SLIGHTLY HIGHER SNOW
TOTALS...AN ADVISORY LOOKS LIKE THE BEST COURSE OF ACTION AT THIS
TIME. REMAINING ZONES/AREAS THAT WILL REQUIRE CLOSE ATTENTION ARE
THE UPPER ARKANSAS VALLEY...IF COLD AIR CONTINUES TO PUSH TO THE
WEST THIS EVENING...AND THE HIGHER TERRAIN OF PUEBLO COUNTY OVER SRN
AND WRN PORTIONS OF THE ZONE.
TONIGHT...LIGHT SNOW WILL CONTINUE AND WILL SPREAD OUT EWD TOWARD
THE KS BORDER. AMOUNTS COULD APPROACH LOW-END ADVISORY LEVELS BY TUE
MORNING. H7 TEMPS CONTINUE TO PLUMMET TO NR MINUS 23 DEGREES...WHICH
TYPICALLY ONLY HAPPENS A COUPLE TIMES EACH WINTER. THE ONLY THING
THAT WILL KEEP THE LOWER ARKANSAS VALLEY FROM HITTING LOWS MINUS 20
DEGREES OR LOWER WILL BE THE EXTENSIVE CLOUDS AND LIGHT SNOW. THIS
WILL SERVE TO KEEP US ON THE `WARM` SIDE...ONLY ZERO TO MINUS 10
DEGREES BY EARLY TUE MORNING. THERE WILL BE BORDERLINE WIND-CHILL
ADVISORY READINGS OVER THE MTS...SAN LUIS VALLEY...AND PIKES PEAK
REGION BUT IT LOOKS FAIRLY SPOTTY AT THIS TIME SO WILL HOLD OFF ON
ISSUING ANY WIND CHILL ALERTS. THE COLDEST AIR STILL LOOKS TO BE ON
TUESDAY AND TUE NIGHT. SO...BREAK OUT LOTS OF LAYERS AND PREPARE FOR
THE COLD! ROSE
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 312 AM MST MON DEC 29 2014
...VERY COLD TUESDAY...THEN WHERE DOES THE UPPER LOW GO LATE IN THE
WEEK?...
TUESDAY...
IT WILL BE VERY COLD ACROSS THE REGION. IT APPEARS NOW THAT ALL
AREAS ON THE PLAINS WILL ONLY SEE HIGH TEMPS IN THE POSITIVE
SINGLE DIGITS. AREAS ON THE PALMER DIVIDE MAY SEE A FEW MAX TEMPS
IN THE NEGATIVE SINGLE DIGITS. I SHOULD NOTE THAT MOS IS A FEW
DEGREES COOLER THAN CURRENT GRIDS...HOWEVER SPC PLUME VIEWER
PRODUCTS LEAN MORE TOWARDS CURRENT NDFD TEMPS...AND CURRENT
FORECASTED HIGH TEMPS MATCH UP WITH SURROUNDING WFO/S. IT WILL BE
CLOUDY OVER THE PLAINS TUESDAY AND SNOW IS LIKELY MOST IF NOT ALL
LOWER ELEVATIONS...ESPECIALLY IN THE MORNING. IT APPEARS THE SNOW
THAT FALLS ON THE PLAINS WILL BE LIGHT...WITH ONLY AN INCH OR TWO
OF NEW SNOW POSSIBLE DURING THE DAY TUESDAY. HIGHER AMOUNTS WILL
BE POSSIBLE ON THE EAST SLOPES OF THE S MTNS.
WIND CHILL READINGS TUESDAY WILL BE THE MAIN CONCERN AS I EXPECT
THESE VALUES WILL RANGE BETWEEN -10 AND -20F MOST OF THE DAY.
MTNS AND VALLEYS WILL SEE SOME LIGHT SNOW...ESPECIALLY C MTNS.
ACCUMS SHOULD BE LIGHT. THE ARCTIC AIR WILL LIKELY GET INTO THE
UPPER ARK RVR VALLEY...HOWEVER THE SAN LUIS VALLEY WILL NOT SEE
THE BRUNT OF THE COLD AIR...AND MAX TEMPS IN THE SLV SHOULD BE IN
THE UPPER TEENS.
TUESDAY NIGHT...
VERY COLD TEMPERATURES ARE CERTAIN. HOW COLD IS THE QUESTION. MIN
TEMPS WILL BE DEPENDENT ON HOW MUCH CLOUDINESS (OR LACK THEREOF) WE
HAVE OVER THE REGION. IT WILL ALSO BE DEPENDENT ON SNOW COVER. FOR
NOW THE NDFD MIN TEMPS RANGE BETWEEN -5 TO -15F OVER THE PLAINS.
IF IT CLEARS OUT AND THERE IS WIDESPREAD SNOW COVER...THEN THESE
TEMPS COULD BE 5 TO 10F COLDER THAN CURRENT FORECASTED LOWS.
WEDNESDAY...
WE START TO MODERATE ACROSS THE REGION...ALTHOUGH IT STILL WILL BE
COLD. I DO NOT EXPECT ANY LOCATIONS IN THE CWA TO GET ABOVE FREEZING
THIS DAY. WARMEST TEMPS WILL LIKELY OCCUR IN THE MID ARK RVR VALLEY
(SALIDA TO CANON CITY) WHERE TEMPS WILL GET INTO THE MID 20S. I
EXPECT THE PLAINS WILL PRIMARILY BE IN THE TEENS WITH A 20S JUST
EAST OF THE MTNS. EXCEPT FOR SOME SHOWERS ALONG THE CONTDVD...IT
WILL BE DRY.
THURSDAY INTO THE WEEKEND...
CONCERN TURN TOWARDS THE CLOSED LOW THAT WILL BE N ARIZ THURSDAY
MORNING. LATEST GUIDANCE IS INDICATING A BIT MORE FAVORABLE TRACK
FOR THE SOUTHERN TIER OF THE FCST AREA...ESPECIALLY THE SAN JUANS
FOR LATE WED INTO EARLY FRIDAY. HAVE INCREASED POPS OVER THE SAN
JUAN REGION THU AND FRI...AND HAVE EXTENDED POPS EASTWARD ACROSS THE
S TIER OF THE PLAINS FRIDAY INTO SATURDAY.
OVER THE REMAINDER OF THE REGION...TEMPS WILL MODIFY WITH TEMPS
RETURNING TO SLIGHTLY BELOW NORMAL TEMPERATURES (~40F PLAINS)
/HODANISH
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 312 AM MST MON DEC 29 2014
AN ARCTIC FRONT WILL PUSH SOUTHWARD INTO SE CO BETWEEN 15 AND 18Z
THIS MORNING. THIS WILL LEAD TO A PROLONGED PERIOD OF MVFR TO IFR
CONDITIONS...AND OCCASIONAL LIFR CONDITIONS...THROUGH TUESDAY. KCOS
AND KPUB WILL SEE THESE CONDITIONS DEVELOP FROM 16-18Z AS LIGHT SNOW
BECOMES MORE WIDESPREAD AND PERSISTENT THROUGH THIS AFTERNOON. WINDS
WILL BE MODERATE FROM THE NE DURING THIS PERIOD. KALS WILL SEE
CONDITIONS DETERIORATE A BIT LATER TODAY AS IT WILL TAKE A WHILE FOR
THE COLD AIR TO SPILL OVER INTO THE SAN LUIS VALLEY...BUT SIMILAR
MVFR-IFR CONDITIONS ARE EXPECTED IN THE HIGH VALLEYS OVERNIGHT INTO
TUE MORNING. ROSE
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 11 AM THIS MORNING TO 5 AM MST
TUESDAY FOR COZ065-069-072>080-083-086>089-093-095>098.
WINTER WEATHER ADVISORY UNTIL 5 AM MST TUESDAY FOR COZ058-060.
WINTER WEATHER ADVISORY UNTIL 5 AM MST TUESDAY FOR COZ081-082-
084.
&&
$$
UPDATE...ROSE
SHORT TERM...ROSE LONG TERM...HODANISH
AVIATION...ROSE
AREA FORECAST DISCUSSION
NWS MIAMI FL
744 PM EST TUE DEC 30 2014
.AVIATION...
WEAK FRONT SETTLING INTO CENTRAL FL TONIGHT, WILL ONLY DELIVER
MORE CLOUDINESS FOR THE SOUTH FLORIDA TERMINALS THROUGH THE PERIOD.
THE EXCEPTION WILL BE APF, WHERE ADVECTION OF SLIGHTLY COOLER AND
DRIER AIR MAY ARRIVE IN TIME FOR LOW CIGS TO FORM NEAR DAWN.
SREF PROBS HAVE HAD A HIGH FALSE ALARM RATIO THE PAST FEW NIGHTS,
WITH REGARDS TO SEA FOG/IFR CIG, SO ITS TOUGH TO TRUST ITS BULLISH
APPROACH. HOWEVER, THIS IS A DIFFERENT SCENARIO WITH A SLIGHTLY
DIFFERENT AIRMASS DRAINING DOWN THE WEST COAST. WITH LAMP GUIDANCE
ALSO INDICATING IFR CIGS, FELT INCLINED TO AT LEAST INCLUDE A FEW
HRS OF AN MVFR CLOUD LAYER NEAR DAWN. CONFIDENCE IS AVG.
&&
.PREV DISCUSSION... /ISSUED 430 PM EST TUE DEC 30 2014/
..VERY WARM, HUMID PATTERN TO CONTINUE INTO THE NEW YEAR...
UPDATE...SEA BREEZES HAVE DEVELOPED ALONG BOTH THE GULF AND
ATLANTIC COASTS THIS AFTERNOON...CLEARLY SEEN IN VISIBLE SATELLITE
IMAGERY. PRETTY RARE FOR WINTERTIME! ENOUGH LOW LEVEL MOISTURE IS
PRESENT TO HAVE CU FORMING ALONG THE SEA BREEZE FRONTS, BUT NOT
QUITE ENOUGH TO GET SHOWERS GOING. HRRR IS OVERDOING QPF AS RADAR
CONTINUES TO SHOW NO SHOWER ACTIVITY (ECHOES SOUTH OF LAKE
OKEECHOBEE ARE REFLECTIVE OF SUGARCANE BURNING). AS DAYTIME
HEATING IS LOST, IT LOOKS LIKE CONDITIONS WILL REMAIN DRY THROUGH
TONIGHT...BUT AS THE WEAKENING COLD FRONT OVER CENTRAL FLORIDA
SAGS SOUTHWARD, SOME CONVERGENCE ALONG THE PALM BEACH COAST COULD
ALLOW FOR A FEW SHOWERS TO DEVELOP THERE LATER TONIGHT...SO KEPT
SHOWER MENTION IN THERE ONLY.
SOUTH FL CONTINUES WITH ABOVE NORMAL TEMPS ALONG WITH
HUMIDITY...AND THIS WILL CONTINUE INTO THE WEEKEND AND EARLY NEXT
WEEK! A RECORD HIGH OF 83F WAS TIED AT MIAMI TODAY. THE HOTTEST
READINGS WERE FROM OPA LOCKA (KOPF) TO PEMBROKE PINES (KHWO) TO
WEST PALM BEACH (KPBI) WHERE HIGHS OFFICIALLY REACHED 85F, THE
WARMEST IN THE COUNTRY (FOR MAJOR REPORTING STATIONS/SOME UPPER
80S WERE REGISTERED BY MESONETS OVER PORTIONS OF INTERIOR SOUTH FL
THIS AFTERNOON).
THE WARM PATTERN WILL CONTINUE WITH POSSIBLY BUILDING HEAT BY THIS
WEEKEND. ECMWF INDICATES MAX TEMPS INTO THE MID-UPPER 80S EAST
COAST METRO WITH DEWPOINTS INTO THE LOWER 70S EQUATING TO HEAT
INDICES INTO THE LOWER 90S! GFS AND MODEL BLENDS OFFER SLIGHTLY
COOLER READINGS...AND THAT`S WHAT OUR CURRENT FORECAST REFLECTS.
HOWEVER, WE VERY WELL MAY NEED TO INCREASE OUR HIGHS PROJECTED FOR
THIS UPCOMING WEEKEND. A POSSIBLE "MINI-HEAT WAVE" TO START 2015.
/GREGORIA
PREV DISCUSSION... /ISSUED 247 PM EST TUE DEC 30 2014/
SHORT TERM (TONIGHT-NEW YEARS` DAY)...
A MOSTLY ZONAL UPPER FLOW PATTERN WILL CONTINUE ACROSS SOUTH FLORIDA
THROUGH NEW YEAR`S DAY AS A STRONG RIDGE REMAINS ACROSS CUBA AND
THE BAHAMA ISLANDS. A WEAK COLD FRONT CURRENTLY IN NORTH CENTRAL
FLORIDA WILL OOZE INTO SOUTH FLORIDA TONIGHT AND WEDNESDAY BEFORE
STALLING AND RAPIDLY BECOMING DIFFUSE. THERE WILL BE SOME CLOUDS
WITH THE FRONTAL BOUNDARY BUT VERY LITTLE IN THE WAY OF RAINFALL
AS DEEP LAYER MOISTURE WILL BE LACKING. THERE IS SOME POTENTIAL
FOR FOG AGAIN OVER THE INTERIOR AHEAD OF THE FRONT. HOWEVER,
EXTENSIVE CLOUD COVER WILL LIKELY HAMPER FOG DEVELOPMENT AND WILL
LEAVE OUT OF FORECAST AT THIS TIME WITH THE SREF ONLY SHOWING A
30-40% CHANCE OF VISIBILITY LOWERING LESS THAN THREE MILES. DUE TO
THE LACK OF PUSH WITH THIS FRONT, THE STRONG SUBSIDENCE CAP
CURRENTLY OVER SOUTH FLORIDA WILL BE SLOW TO ERODE WITH FORECAST
SOUNDINGS ONLY INDICATING SOME INSTABILITY BY LATE WEDNESDAY AND
EVEN THEN A PWAT OF ONLY AROUND 1.3".
LONG TERM (FRIDAY-TUESDAY)...
NOT MANY CHANGES SEEN TO THE UPPER FLOW PATTERN IN THE EXTENDED
PERIOD AS THE SUBTROPICAL RIDGE REMAINS FIRMLY ENTRENCHED IN ITS
POSITION ACROSS THE BAHAMA ISLAND CHAIN. AT THE SURFACE, WHAT IS
LEFT OF THE FRONTAL BOUNDARY WILL LIFT BACK TO THE NORTH WEDNESDAY
NIGHT OR THURSDAY. THIS IS IN RESPONSE TO A POWERFUL TROUGH
CURRENTLY DEEPENING INTO THE FOUR CORNERS AREA THAT WILL MOVE INTO
THE CENTRAL/SOUTHERN PLAINS ON FRIDAY NIGHT AND SATURDAY THEN INTO
THE GREAT LAKES AND NEW ENGLAND THIS WEEKEND. A COLD FRONT
ASSOCIATED WITH THIS SYSTEM WILL THEN MOVE INTO NORTH FLORIDA ON
SUNDAY WHERE IT WILL STALL INTO EARLY NEXT WEEK. SO THESE TWO
PARAGRAPHS SPELL OUT A WARM AND GENERALLY DRY PATTERN FOR SOUTH
FLORIDA TO END THIS YEAR AND THE BEGINNING OF THE NEW YEAR.
MARINE...
GOOD BOATING CONDITIONS WILL CONTINUE THROUGH THE FORECAST PERIOD
WITH A LIGHT WIND EXPECTED AND SEAS 4 FEET OR LESS. THE PRESSURE
GRADIENT WILL REMAIN WEAK AS THE COLD FRONT BECOMES DIFFUSE AND
THEN SLOWLY LIFTS TO THE NORTH TOWARDS THE END OF THE WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 69 79 68 78 / 20 40 20 20
FORT LAUDERDALE 70 80 69 79 / 10 30 20 20
MIAMI 70 81 69 80 / 10 20 10 20
NAPLES 66 79 65 79 / 10 20 10 10
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
SHORT TERM...57/DG
LONG TERM....57/DG
AVIATION...21/KM
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
200 PM EST MON DEC 29 2014
.SYNOPSIS...
18Z WATER VAPOR AND H4 RAP ANALYSIS SHOW THAT MUCH OF THE CONUS IS
NOW UNDER BROAD LONGWAVE TROUGHING...AS THE RIDGE THAT WAS ALONG THE
EASTERN SEABOARD HAS BEEN DEAMPLIFIED BY SHORTWAVE ENERGY PASSING
OFF THE CAROLINA COAST AND PUSHED SOUTHEAST INTO THE WESTERN
ATLANTIC. THE CENTRAL/SOUTHERN FLORIDA PENINSULA IS STILL SOMEWHAT
UNDER THE SUBSIDENCE OF THIS RIDGE...BUT HEIGHTS HAVE CERTAINLY COME
DOWN ACROSS THE PENINSULA DURING THE PAST 24 HOURS. THE MOST
INTERESTING FEATURE IN THE UPPER LEVELS IS A STRONG PIECE OF
SHORTWAVE/JET ENERGY DIVING DOWN THE PACIFIC COAST. THIS ENERGY IS
PROGGED TO EVOLVE INTO A LARGE CUTOFF LOW OVER THE SOUTHWESTERN
STATES BY THE MIDDLE OF THE WEEK AND THEN SLOWLY EJECT EASTWARD
ACROSS THE SOUTHERN PLAINS.
29/12Z KTBW SOUNDING PROFILE SHOWS THAT ALTHOUGH THE RIDGE ALOFT IS
WEAKENING...IT STILL HAS SOME INFLUENCE ON THE REGION. AN ASSOCIATED
SUBSIDENCE INVERSION IS EVIDENT AROUND 850MB WITH QUITE A DRY COLUMN
ABOVE IN THE MID LAYERS OF THE ATMOSPHERE.
AT THE SURFACE...ATLANTIC HIGH PRESSURE RIDGES BACK OVER THE CENTRAL
AND SOUTHERN FL PENINSULA...WHILE AT THE SAME TIME A COLD FRONT
SLOWLY CRAWLS SLOWLY THROUGH THE EASTERN GULF OF MEXICO. THE FLOW
BETWEEN THESE 2 FEATURES IS PROVIDING ABUNDANT LOW LEVEL MOISTURE TO
THE REGION. THESE RICH DEWPOINTS (LOWER 70S AT BUOY 42036) ARE
ADVECTING OVER THE LOWER 60S TEMPERATURE SHELF WATERS OF EASTERN
APALACHEE BAY AND RESULTED IN AREAS OF DENSE SEA FOG EARLIER TODAY.
THIS FOG HAS SINCE MIGRATED MOSTLY TO THE NORTH OF OUR COASTAL
ZONES...BUT AM EXPECTING IT TO REDEVELOP LATER THIS EVENING AND
OVERNIGHT...AND ALSO LIKELY TO SEE THE AREAL COVERAGE OF THE SEA FOG
EXPAND SOUTHWARD OVERNIGHT. THIS EXPANSION CONTINUES TO BE SHOWN
BY THE SREF AND ALSO THE ENSEMBLE LOCAL SUITE OF HIGH RESOLUTION
GUIDANCE.
&&
.SHORT TERM (REST OF TODAY THROUGH TUESDAY)...
REST OF TODAY...
STILL CALLING IT A "MIX OF SUN AND CLOUDS" AS A SCT CUMULUS FIELD
HAS BECOME WELL ESTABLISHED THIS AFTERNOON. INLAND LOCATIONS...
ESPECIALLY ALONG AND SOUTH OF THE I-4 CORRIDOR ARE NOW IN THE LOWER
80S...WHILE THINGS HOLD IN THE 70S AT THE BEACHES DUE TO THE ONSHORE
COMPONENT TO THE WIND. THE COLD FRONT WILL BE MAKING VERY SLOW
PROGRESS EASTWARD INTO THE EVENING BUT WILL FAIL TO REACH OUR VERY
NORTHERN COUNTIES UNTIL LATER TONIGHT. EVEN STILL...A FEW SHOWERS
AHEAD OF THE BOUNDARY MAY REACH LEVY COUNTY AND THE NORTHERN COASTAL
WATERS BY EARLY THIS EVENING...HOWEVER THE BETTER SHOWER CHANCES
WILL EXIST FOR LEVY/CITRUS COUNTIES LATER EVENING AND OVERNIGHT.
TONIGHT...
THE APPROACH OF ONE FINAL PIECE OF WEAK SHORTWAVE ENERGY OVER THE
NORTHERN GULF COAST WILL FINALLY GIVE THE FRONT THE PUSH IT NEEDS TO
ENTER THE FL PENINSULA. THE BOUNDARY SHOULD BE LOCATED SOMEWHERE
BETWEEN TAMPA AND CHIEFLAND BY SUNRISE ON TUESDAY. WILL HAVE TO PUT
A FEW SHOWERS IN THE FORECAST FROM TAMPA NORTHWARD IN PROXIMITY TO
THIS BOUNDARY...HOWEVER ANY RAINFALL DOES NOT LOOK TO BE A BIG
DEAL...WITH VERY LOW QPF. TEMPERATURES WILL REMAIN ABOVE NORMAL WITH
LOWS IN THE 60S FOR ALL. BIGGER FORECAST CONCERN IS THE POTENTIAL
FOR SEA FOG DEVELOPMENT WHICH IS SHOWN BY MANY OF THE RELIABLE
GUIDANCE MEMBERS. LOW LEVEL FLOW WILL BE OUT OF THE SOUTHWEST AHEAD
OF THE FRONT TONIGHT...SO ANY SEA FOG THAT DOES DEVELOP WILL BE
ADVECTED ONSHORE. SEA FOG HAS GENERAL RULES WHICH HELP US DETERMINE
WHEN IT WILL DEVELOP BUT TRYING TO PREDICT EXACTLY WHERE/WHEN AND IT
EVOLUTION ONCE DEVELOPED IS VERY DIFFICULT. WILL HAVE FOG IN THE
FORECASTS EVENING AND OVERNIGHT SHIFT WILL SIMPLY NEED TO MONITOR
THE SITUATION WITH REGARDS TO ANY MARINE OR LAND BASED DENSE FOG
ADVISORIES.
TUESDAY...
COLD FRONT MAKES SLOW BUT STEADY PROGRESS SOUTHWARD THROUGH THE DAY
REACHING THE SOUTHERN FL PENINSULA TUESDAY EVENING. ANY SEA FOG WILL
STILL BE GOING TO BEGIN THE DAY...AND THE THREAT WILL NOT END UNTIL
THE PASSAGE OF THE COLD FRONT. A FEW SHOWERS WILL REMAIN IN THE
FORECAST...ALTHOUGH THE BEST CHANCES WILL SLIP TO THE SOUTHERN HALF
OF THE REGION BY THE AFTERNOON. DO NOT ANTICIPATE THAT TUESDAY WILL
BE CONSIDERED A "WET" DAY. ONCE AGAIN...ANY SHOWERS SHOULD BE BRIEF
AND QPF IS QUITE LOW. THERE REALLY IS NOT A WHOLE LOT OF COLD AIR
BEHIND THIS COLD FRONT. WE WILL SEE SOME DECREASE IN TEMPS INTO THE
MIDDLE OF THE WEEK...BUT MAINLY IT WILL GET DRIER AND MORE
COMFORTABLE FEELING. HOWEVER...DO NOT GET USED TO IT...AS ALL SIGNS
POINT TO A QUICK MODERATING TREND IN BOTH TEMPERATURES AND DEWPOINTS
AS HEAD TOWARD THE END OF THE WEEK.
&&
LONG TERM (WEDNESDAY THROUGH NEXT MONDAY)...
GFS AND ECMWF IN GOOD AGREEMENT WITH DIGGING A CLOSED LOW INTO NEW
MEXICO BY FRIDAY WITH A SOLID RIDGE OF HIGH PRESSURE OVER FLORIDA.
THE NEXT FRONT IS EXPECTED TO MOVE THROUGH SUNDAY NIGHT AND MONDAY.
THIS FRONT WILL BE SIMILAR TO THE TUESDAY FRONT WITH LIMITED RAIN AS
DYNAMICS REMAIN TO THE NORTH.
EXPECT ONLY A SLIGHT CHANCE OF SHOWERS TUESDAY NIGHT SOUTH OF
SEBRING TO PUNTA GORDA AS FRONT SLOWLY MOVES SOUTH OF FORECAST AREA.
MINOR IMPULSES ZIPPING ALONG ZONAL FLOW ALOFT HAS GFS/ECMWF WITH A
SMALL CHANCE OF RAIN IN SOUTHWEST FLORIDA WEDNESDAY. WILL LEAVE DRY
FOR NOW AS AREA IS BEHIND SURFACE FRONT AND ONLY EXPECT BATCHES OF
MID CLOUDS AND A FEW SPRINKLES.
WEDNESDAY WILL BE THE COOLEST DAY OF THE NEXT SEVEN DAYS...BUT WILL
STILL ABOUT 5 DEGREES ABOVE NORMAL. TEMPERATURES OF 10-15 DEGREES
ABOVE NORMAL EXPECTED THURSDAY THROUGH THE WEEKEND...ESPECIALLY ON
OVERNIGHT LOWS.
COLD FRONT MOVES SOUTH THROUGH AREA ON MONDAY WITH A SLIGHT CHANCE
OF RAIN SHOWERS. NO REAL COOL DOWN IN SIGHT.
&&
.AVIATION...
VFR CONDITIONS PREVAIL ACROSS THE REGION THIS AFTERNOON AND
ANTICIPATE THESE CONDITIONS TO LAST INTO THE EVENING HOURS. AFTER
MIDNIGHT INTO TUESDAY MORNING THE POTENTIAL EXISTS FOR WIDESPREAD
VIS/CIG RESTRICTIONS. THE STATISTICAL AND DETERMINISTIC GUIDANCE ARE
ALL SUGGESTING FAVORABLE CONDITIONS FOR A COMBINATION OF LAND BASED
FOG DEVELOPMENT AND SEA FOG ADVECTING ONSHORE. SINCE A LOT OF THE
FORECAST IS CONDITIONAL ON THE DEVELOPMENT OF SEA FOG HAVE KEPT
THINGS IN THE MVFR CATEGORY JUST ABOVE IFR...HOWEVER THE POTENTIAL
EXISTS FOR MUCH MORE SIGNIFICANT RESTRICTIONS AFTER MIDNIGHT. THE
SITUATION WILL NEED TO BE MONITORED CLOSELY. IF WIDESPREAD
SIGNIFICANT RESTRICTIONS DO DEVELOP...THEY ARE LIKELY TO BE VERY
SLOW TO IMPROVE TUESDAY MORNING.
&&
.MARINE...
DENSE FOG WILL REMAIN POSSIBLE OVER THE WATERS LATER TONIGHT AS
WARM...HUMID AIR CONTINUES TO OVERRIDE THE COOLER GULF WATERS. A
WEAK FRONTAL BOUNDARY WILL APPROACH THE AREA LATE TONIGHT AND INTO
TUESDAY WITH A SLIGHT CHANCE OF SHOWERS POSSIBLE. THE WINDS WILL
SHIFT TO THE NORTH AND NORTHEAST IN THE WAKE OF THIS FRONT ON
TUESDAY...AND WILL REMAIN OUT OF THE NORTHEAST THROUGH THE REMAINDER
OF THE UPCOMING WEEK AS HIGH PRESSURE SETTLES INTO THE REGION.
&&
.FIRE WEATHER...
NO SIGNIFICANT FIRE WEATHER CONCERNS OTHER THAN FOG EXPECTED THE
NEXT SEVERAL DAYS. A WEAK COLD FRONT WILL CROSS THE REGION ON
TUESDAY WITH A FEW SHOWERS...AND THEN BE FOLLOWED BY A SLIGHTLY
DRIER AIRMASS FOR WEDNESDAY AND THURSDAY.
FOG POTENTIAL...AREAS OF FOG ARE EXPECTED TO DEVELOP OVER LAND AND
ALSO SEA FOG MOVING ASHORE OVERNIGHT AND TUESDAY MORNING. SOME OF
THE FOG IS EXPECTED TO BECOME DENSE. AREAS NEAR THE COAST THAT
EXPERIENCE SEA FOG MAY BE IN THE FOG FOR AN EXTENDED PERIOD OF TIME
FROM LATER TONIGHT INTO TUESDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 67 75 62 74 / 10 30 0 10
FMY 66 79 65 79 / 0 20 20 20
GIF 65 78 61 74 / 0 30 10 10
SRQ 66 76 63 75 / 0 30 0 10
BKV 63 76 56 73 / 20 30 0 10
SPG 67 74 62 73 / 10 30 0 10
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
SYNOPSIS/SHORT TERM/AVIATION/FIRE WEATHER...MROCZKA
LONG TERM...NOAH
MARINE...MCKAUGHAN
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
930 AM EST MON DEC 29 2014
.DISCUSSION...
...HIGH RISK OF RIP CURRENTS ONCE AGAIN AT THE BEACHES...
...NEAR RECORD HIGH TEMPERATURES TODAY...
MILD WX PATTERN CONTINUES AS A WEAK FRONTAL TROF OVER THE
CENTRAL/ERN GOMEX CREEPS TOWARD THE FL PENINSULA. PROGRESS WILL BE
SLOW AS THE RUC ANALYSIS SHOWS A DEEP HIGH PRES RIDGE AHEAD OF THE
FRONT EXTENDING FROM THE YUCATAN PENINSULA ACRS NRN CUBA AND THE
CENTRAL BAHAMAS. MORNING RAOBS AT KJAX/KTBW SHOW PWATS ARND 1.0"
INCREASING TO 1.3" AT KMFL...SHARP SUBSIDENCE INVERSIONS THRU THE
H90-H75 LYR...AND DEEP S/SWRLY FLOW THRU THE COLUMN. LCL CONVERGENCE
ZONE BTWN THE TREASURE COAST AND THE NRN BAHAMAS HAS ALLOWED ISOLD
SHRAS TO FORM S OF VERO BEACH...BUT THE PREVAILING SRLY STEERING
FLOW HAS KEPT MOST OF THESE OFFSHORE.
ASIDE FROM BRIEF PDS OF LIGHT RAIN ALONG THE TREASURE COAST...FCST
WILL REMAIN DRY. SKIES WILL REMAIN PTLY/MSUNNY WITH STEADY S/SW
WINDS PUSHING AFTN MAX TEMPS TO WITHIN A DEG OR TWO OF THEIR DAILY
RECORDS. FRNTL BNDRY OVER THE PANHANDLE WILL APPROACH THE BIG BEND
REGION BY SUNSET...BUT WILL REMAIN TOO FAR TO THE NW TO ALLOW ANY
PRECIP TO DVLP UNTIL AFT MIDNIGHT.
A PERSISTENT LONG PERIOD E/NE SWELL WILL DIMINISH TODAY BUT WILL
CONTINUE TO PRODUCE A HIGH RIP CURRENT THREAT ALONG AREA BEACHES
THIS AFTN.
&&
.AVIATION...THRU 30/12Z
SFC WNDS: THRU 30/02Z...S/SW BTWN 6-9KTS...BCMG S/SE CSTL SITES S OF
KMLB AFT 28/18Z. BTWN 30/02Z-30/04Z...S/SW 3-5KTS. AFT 30/04Z...W/SW
AOB 3KTS.
VSBYS/WX: THRU 30/00Z...S OF KVRB ISOLD MVFR SHRAS. BTWN
30/00Z-30/04Z...VFR. BTWN 30/04Z-30/08Z...S OF KMLB-KISM AREAS MVFR
BR/LCL LIFR FG...CONTG THRU 30/12Z. AFT 30/08Z...SLGT CHC MVFR
-SHRAS N OF KTIX-KISM.
CIGS: THRU 30/00Z...AREAS BTWN FL020-030 S OF KVRB IN ISOLD SHRAS.
BTWN 30/00Z-30/04Z...BTWN FL040-060. AFT 30/04Z...N OF KMLB-KISM
BTWN FL020-030 WITH AREAS BLO FL010...S OF KMLB-KISM BTWN FL040-060
WITH AREAS BTWN FL020-030.
&&
.MARINE...
RIDGE AXIS EXTENDING FROM THE YUCATAN PENINSULA ACRS NRN CUBA THRU
THE CENTRAL BAHAMAS WILL INTERACT WITH A WEAK FRONTAL TROF OVER THE
CENTRAL/ERN GOMEX TO GENERATE A GENTLE TO MODERATE A/SWRLY BREEZE
THRU MIDNIGHT...BCMG LIGHT TO GENTLE W/SW THRU THE PREDAWN HRS AS
THE TROF PRESSES INTO THE N FL PENINSULA. PERSISTENT LONG PD SWELL
WILL CONTINUE BEGIN TO DAMPEN OUT AS WINDS SHIFT TO THE MORE WRLY
COMPONENT...SEAS 2-3FT NEARSHORE AND 3-4FT OFFSHORE THRU SUNSET BCMG
2-3FT AREAWIDE AFT SUNSET.
&&
.CLIMATE...
RECORD HIGHS FOR TODAY 29 DECEMBER...
DAYTONA BEACH 83/1946
ORLANDO 84/2007
MELBOURNE 84/1973
VERO BEACH 85/2012
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
SHORT TERM/AVIATION...BRAGAW
LONG TERM/IMPACT WX...LASCODY
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
905 AM EST MON DEC 29 2014
.UPDATE (REST OF TODAY THROUGH TUESDAY)...
14Z WATER VAPOR AND H4 RAP ANALYSIS SHOW THAT MUCH OF THE CONUS IS
NOW UNDER BROAD LONGWAVE TROUGHING...AS THE RIDGE THAT WAS ALONG THE
EASTERN SEABOARD HAS BEEN DEAMPLIFIED BY SHORTWAVE ENERGY PASSING
OFF THE CAROLINA COAST AND PUSHED SOUTHEAST INTO THE WESTERN
ATLANTIC. THE CENTRAL/SOUTHERN FLORIDA PENINSULA IS STILL SOMEWHAT
UNDER THE SUBSIDENCE OF THIS RIDGE...BUT HEIGHTS HAVE CERTAINLY COME
DOWN ACROSS THE PENINSULA DURING THE PAST 24 HOURS. THE MOST
INTERESTING FEATURE IN THE UPPER LEVELS IS A STRONG PIECE OF
SHORTWAVE/JET ENERGY DIVING DOWN THE PACIFIC COAST. THIS ENERGY IS
PROGGED TO EVOLVE INTO A LARGE CUTOFF LOW OVER THE SOUTHWESTERN
STATES BY THE MIDDLE OF THE WEEK AND THEN SLOWLY EJECT EASTWARD
ACROSS THE SOUTHERN PLAINS.
29/12Z KTBW SOUNDING PROFILE SHOWS THAT ALTHOUGH THE RIDGE ALOFT IS
WEAKENING...IT STILL HAS SOME INFLUENCE ON THE REGION. AN ASSOCIATED
SUBSIDENCE INVERSION IS EVIDENT AROUND 850MB WITH QUITE A DRY COLUMN
ABOVE IN THE MID LAYERS OF THE ATMOSPHERE.
AT THE SURFACE...ATLANTIC HIGH PRESSURE RIDGES BACK OVER THE CENTRAL
AND SOUTHERN FL PENINSULA...WHILE AT THE SAME TIME A COLD FRONT
SLOWLY CRAWLS EASTWARD THROUGH THE FL PANHANDLE AND NORTH-CENTRAL
GULF OF MEXICO. THE FLOW BETWEEN THESE 2 FEATURES IS PROVIDING
ABUNDANT LOW LEVEL MOISTURE TO THE REGION. THESE RICH DEWPOINTS
(LOWER 70S AT BUOY 42036) ARE ADVECTING OVER THE LOWER 60S
TEMPERATURE SHELF WATERS OF EASTERN APALACHEE BAY AND RESULTING IN
AREAS OF DENSE SEA FOG. HAVE ISSUED A MARINE DENSE FOG ADVISORY FOR
THE COASTAL WATERS NORTH OF PINELLAS COUNTY. FOR NOW MOST OF THE FOG
IS UP TOWARD THE COASTS OF CITRUS/LEVY COUNTIES...BUT THERE IS A
GOOD CHANCE TO SEE AN EXPANSION OF THIS FOG SOUTHWARD LATER TODAY
AND ESPECIALLY INTO TONIGHT. THIS EXPANSION IS SHOWN BY THE SREF AND
ALSO THE ENSEMBLE LOCAL SUITE OF HIGH RESOLUTION GUIDANCE.
REST OF TODAY...
FOG OVER LAND WILL BURN OFF IN THE NEXT FEW HOURS. ONLY EXCEPTION
MAY BE AT THE IMMEDIATE COASTS OF CITRUS AND LEVY COUNTY AS THE SEA
FOG MOVES ASHORE AND IS NOT INFLUENCED BY DIURNAL MIXING. WILL CALL
IT A "MIX OF SUN AND CLOUDS" IN THE FORECAST AS WE DO HAVE SEVERAL
PATCHES OF CLOUDS AND CLEAR SKIES ACROSS THE REGION. ALL WE NEED IS
A LITTLE BIT OF SUN GIVEN THE THERMAL POTENTIAL OF THE LOW LEVEL
COLUMN TO END UP WITH AN ABOVE NORMAL DAY IN TERMS OF TEMPERATURES.
INLAND LOCATIONS...ESPECIALLY ALONG AND SOUTH OF THE I-4 CORRIDOR
SHOULD REACH THE LOWER 80S...WHILE THINGS HOLD IN THE 70S AT THE
BEACHES DUE TO A DEVELOPING ONSHORE COMPONENT TO THE WIND THIS
AFTERNOON. THE FRONT WILL BE MAKING VERY SLOW PROGRESS EASTWARD
THROUGH THE DAY BUT WILL FAIL TO REACH OUR COUNTIES TODAY. EVEN
STILL...A FEW SHOWERS AHEAD OF THE BOUNDARY MAY REACH LEVY COUNTY
AND THE NORTHERN COASTAL WATERS BY EARLY THIS EVENING. JUST HAVE A
20% CHANCE OF A SHOWER THROUGH THE EVENING FOR LEVY COUNTY AS THE
OVERALL SYNOPTIC SETUP FOR LIFT ALONG THE BOUNDARY WILL BE FADING
WITH TIME. CAN NOT RULE OUT A BRIEF SHOWER OR 2 DEVELOPING OVER THE
INTERIOR SOUTH-CENTRAL ZONES EITHER AS A RESULT OF A LATE DAY
SEA-BREEZE MERGER. A FEW OF THE LOCAL CONVECTION ALLOWING MODELS ARE
SHOWING THIS POTENTIAL AND WILL KEEP THE 20% POP AFTER 18Z OVER
HIGHLANDS COUNTY.
TONIGHT...
THE APPROACH OF ONE FINAL PIECE OF WEAK SHORTWAVE ENERGY OVER THE
NORTHERN GULF COAST WILL FINALLY GIVE THE FRONT THE PUSH IT NEEDS TO
ENTER THE FL PENINSULA. THE BOUNDARY SHOULD BE LOCATED SOMEWHERE
BETWEEN TAMPA AND CHIEFLAND BY SUNRISE ON TUESDAY. WILL HAVE TO PUT
A FEW SHOWERS IN THE FORECAST FROM TAMPA NORTHWARD IN PROXIMITY TO
THIS BOUNDARY...HOWEVER ANY RAINFALL DOES NOT LOOK TO BE A BIG
DEAL...WITH VERY LOW QPF. TEMPERATURES WILL REMAIN ABOVE NORMAL WITH
LOWS IN THE 60S FOR ALL.
TUESDAY...
COLD FRONT MAKES SLOW BUT STEADY PROGRESS SOUTHWARD THROUGH THE DAY
REACHING THE SOUTHERN FL PENINSULA TUESDAY EVENING. A FEW SHOWERS
WILL REMAIN IN THE FORECAST...ALTHOUGH THE BEST CHANCES WILL SLIP TO
THE SOUTHERN HALF OF THE REGION BY THE AFTERNOON. DO NOT ANTICIPATE
THAT TUESDAY WILL BE CONSIDERED A "WET" DAY. ONCE AGAIN...ANY
SHOWERS SHOULD BE BRIEF AND QPF IS QUITE LOW. THERE REALLY IS NOT A
WHOLE LOT OF COLD AIR BEHIND THIS COLD FRONT. WE WILL SEE SOME
DECREASE IN TEMPS INTO THE MIDDLE OF THE WEEK...BUT MAINLY IT WILL
GET DRIER AND MORE COMFORTABLE FEELING. HOWEVER...DO NOT GET USED TO
IT...AS ALL SIGNS POINT TO A QUICK MODERATING TREND IN BOTH
TEMPERATURES AND DEWPOINTS AS HEAD TOWARD THE END OF THE WEEK.
&&
.AVIATION...
CONDITIONS HAVE RETURNED TO VFR FOR ALL TERMINALS THIS MORNING.
AREAS OF BKN CLOUDS 3500-4500 FEET WILL BE AROUND...BUT DO NOT
ANTICIPATE ANY ADDITIONAL RESTRICTIONS ALONG OR SOUTH OF THE I-4
CORRIDOR THE REMAINDER OF THE DAY AND EVENING HOURS. AFTER MIDNIGHT
INTO EARLY TUESDAY MORNING IS LOOKING MORE AND MORE FAVORABLE FOR
PERIOD OF SIGNIFICANT RESTRICTIONS AT ALL TERMINALS. THE STATISTICAL
AND DETERMINISTIC GUIDANCE SOLUTIONS ARE ALL POINTING TO WIDESPREAD
DENSE FOG AND LOW CEILINGS. WILL CONTINUE TO MONITOR THE INCOMING
GUIDANCE AND BEGIN TO MAKE ADJUSTMENTS WITH THE 18Z TAF PACKAGE.
&&
.MARINE...
DENSE FOG ADVISORY REMAINS IN EFFECT FOR THE NORTHERN COASTAL WATERS
AS WARM...HUMID AIR CONTINUES TO OVERRIDE THE COOLER WATERS. PATCHY
FOG WILL BE POSSIBLE ACROSS THE REST OF THE WATERS TODAY BUT BEST
CHANCES APPEAR TO BE NORTH OF PINELLAS COUNTY.
OTHERWISE...A WEAK FRONTAL BOUNDARY WILL APPROACH THE AREA LATE
TONIGHT AND INTO TUESDAY WITH A SLIGHT CHANCE OF SHOWERS POSSIBLE.
THE WINDS WILL SHIFT TO THE NORTH AND NORTHEAST IN THE WAKE OF THIS
FRONT ON TUESDAY...AND WILL REMAIN OUT OF THE NORTHEAST THROUGH THE
REMAINDER OF THE UPCOMING WEEK AS HIGH PRESSURE SETTLES INTO THE
REGION.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 78 67 77 61 / 10 10 30 10
FMY 82 66 81 65 / 10 10 20 10
GIF 81 65 79 61 / 10 10 30 10
SRQ 79 65 77 62 / 10 10 30 10
BKV 80 63 78 55 / 10 20 30 10
SPG 77 66 76 62 / 10 10 30 10
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...DENSE FOG ADVISORY UNTIL 1 AM EST TUESDAY FOR TARPON
SPRINGS TO SUWANNEE RIVER OUT 20 NM-TARPON SPRINGS TO
SUWANNEE RIVER OUT 20 TO 60 NM.
&&
$$
UPDATE/AVIATION...MROCZKA
MARINE...MCKAUGHAN
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
344 AM EST MON DEC 29 2014
.SYNOPSIS...
A COLD FRONT WILL PUSH SOUTH THROUGH THE AREA LATE THIS AFTERNOON
INTO TONIGHT. HIGH PRESSURE WILL BUILD INTO THE AREA TUESDAY INTO
FRIDAY...BEFORE MOVING INTO THE ATLANTIC BY SATURDAY. A COASTAL
TROUGH WILL DEVELOP EARLY THIS WEEKEND THEN LIFT NORTH OF THE
REGION ON SUNDAY. A COLD FRONT FRONT WILL THEN PASS OFF THE COAST
EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TODAY/...
...DIFFICULT FOG FORECAST THIS MORNING...
THROUGH MID-MORNING...DENSE FOG WILL REMAIN A CONCERN AS
WARM/MOIST AIR CONTINUES TO ADVECT NORTHWARD INTO THE REGION AHEAD
OF AN APPROACHING COLD FRONT. DENSE SEA FOG HAS ENCOMPASSED MUCH
OF CHARLESTON COUNTY AND IS BLEEDING INTO PORTIONS OF BERKELEY...
DORCHESTER AND COLLETON COUNTIES WHERE WIDESPREAD DENSE RADIATION
FOG IS ALSO OCCURRING. VISIBILITIES HAVE BEEN NEAR ZERO AT TIMES
PER SPOTTER AND COUNTY WARNING POINT REPORTS...BUT SOME
IMPROVEMENTS IN VISIBILITIES HAVE BEEN NOTED IN THE PAST 1-2 HOURS
AT A FEW SITES. IT IS UNCLEAR WHETHER THIS IS TEMPORARY IMPROVEMENT
OR THE BEGINNING OF A MORE DEFINITIVE TREND. WINDS HAVE INCREASED
TO AS HIGH AS 20 KT ATOP THE FOG LAYER PER KCLX VAD WIND PROFILE
DATA AND MAY BE HELPING TRANSITION SOME OF THE FOG INTO A VERY LOW
STRATUS DECK. RAP 1000 FT WINDS ARE PROGGED TO INCREASE TO 25-30
KT BY SUNRISE...SO THE FOG FORECAST IS CERTAINLY NOT CLEAR CUT.
FARTHER SOUTH...SATELLITE AND SURFACE OBSERVATIONS SHOW A LARGE
AREA OF SEA FOG AND LOW STRATUS WITH ORIGINS FROM THE NORTHEAST
GULF OF MEXICO IS POISED TO MOVE NORTH OF THE ALTAMAHA RIVER
THROUGH SUNRISE. VISIBILITIES MAY VERY WELL DROP BELOW 1/4 MILE
ACROSS PARTS OF SOUTHEAST GEORGIA AND THE REMAINDER OF SOUTHEAST
SOUTH CAROLINA OVER THE NEXT FEW HOURS AS SOME STRATUS BUILD DOWN
OCCURS. TRENDS ARE BEING WATCHED FOR A POSSIBLE EXPANSION OF THE
DENSE FOG ADVISORY. AGAIN...IT IS UNCLEAR HOW THE INCREASE IN 1000
FT WINDS WILL AFFECT THE FOG POTENTIAL IN THIS AREA.
SHOWER ACTIVITY ASSOCIATED WITH A WEAK AREA OF WARM AIR ADVECTION
AHEAD OF AN APPROACHING COLD FRONT WILL LARGELY REMAIN WEST OF THE
AREA THROUGH MID-MORNING.
REST OF TODAY...A WAVE FRONTAL WAVE AND COLD FRONT WILL DROP SOUTH
INTO THE AREA TODAY SHEAR SHORTWAVE ENERGY PASSES OFF TO THE
NORTH. DEEP MOISTURE COUPLED WITH ANAFRONTAL UPGLIDE AS WELL AS UVM
INDUCED BY THE RIGHT ENTRANCE REGION OF A 110 KT JET STREAK WILL
SUPPORT SCATTERED TO NUMEROUS SHOWERS THIS AFTERNOON. MODELS ARE
SIMILAR IN SHOWING LITTLE IN THE WAY OF MEASURABLE RAINFALL
THROUGH LATE MORNING WITH ACTIVITY BLOSSOMING OVER MUCH OF
SOUTHEAST SOUTH CAROLINA AND SOUTHEAST GEORGIA DURING THE MID-LATE
AFTERNOON AS THE RIBBON OF STRONG JET DYNAMICS PASSES OVERHEAD.
WILL HIGHLIGHT LIKELY POPS TODAY OF 60-70 PERCENT. DESPITE THE
WARM TEMPERATURES...THE ATMOSPHERE LOOKS TOO MOIST AND STABLE TO
SUPPORT MUCH OF THE WAY OF THUNDER FOR MUCH OF THE DAY. THE ONLY
EXCEPTION WOULD BE IN A NARROW CORRIDOR JUST AHEAD OF THE COLD
FRONT FROM ROUGHLY LUDOWICI TO SAVANNAH...HILTON HEAD AND POINTS
SOUTH WHERE NAM12/GFS BOUNDARY LAYER LIFTED INDEX AND 850 HPA
SHOWALTER FIELDS SUGGEST THERE MAY BE JUST ENOUGH SURFACE AND
ELEVATED INSTABILITY TO SUPPORT AN ISOLATED TSTM OR TWO. HIGHS
WILL RANGE FROM THE MID 60S WELL INLAND TO THE UPPER 60S TO LOWER
70S ACROSS THE COASTAL COUNTIES WITH A FEW MID 70S ACROSS MCINTOSH
COUNTY.
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY/...
TONIGHT...THE WEAK COLD FRONT WILL DROP SOUTH THROUGH THE AREA
OVERNIGHT. THE BEST CHANCE FOR RAIN WILL OCCUR THIS EVENING AS THE
LAST OF THE SHEARED SHORTWAVE ENERGY PASSES OFFSHORE AND TO THE
NORTH. THE PRIMARY FRONTAL BAND RAIN ACTIVITY WILL GRADUALLY
DISSIPATE WITH TIME AS THE FRONT SHIFTS SOUTH AND OFFSHORE. WILL
CARRY 50-70 PERCENT POPS DURING THE EVENING HOURS...HIGHEST ACROSS
THE COASTAL COUNTIES...WITH POPS STEADILY DIMINISHING THROUGH THE
NIGHT AS THE FRONT CLEARS THE AREA AND MID-LEVEL DRY AIR
ADVECTS IN FROM THE SOUTHWEST. LOWS WILL RANGE UPPER 40S WELL
INLAND TO THE UPPER 50S ALONG THE GEORGIA COAST.
TUESDAY...THE COLD FRONT IS EXPECTED TO BE OFFSHORE EXTENDING BACK
INTO NE FLORIDA DURING THE MORNING. THERE COULD BE AREAS OF LOW
CLOUDS IN THE FRONTAL TROUGH BEFORE STRATOCUMULUS EXPAND DURING
THE DAY. MODELS INDICATE A FAST MAINLY ZONAL FLOW ALOFT WITH A
BUCKLED SURFACE PATTERN TO THE LEE OF THE MOUNTAINS AS COLD AIR
ADVECTION BUILDS ACROSS THE CAROLINAS. WEAK DOWNSLOPE AND SLOWER LOW
LEVEL COLD AIR ADVECTION PATTERN IN SE GEORGIA SUGGEST MILDER TEMPS
WITH SOME AFTERNOON CLEARING POSSIBLE. TO THE NORTH...WE MAINTAINED
PLENTY OF CLOUDS ACROSS SOUTH CAROLINA AND KEEP POPS SILENT. SOME
UPPER FORCING MAY LEAD TO A FEW SPRINKLES NORTHERN ZONES BUT THE
DEEPER LAYERS LOOK TOO DRY TO KEEP ANY LINGERING POPS. WE LOWERED
HIGH TEMPS OVER FAR NORTHERN ZONES DUE THE EXPANSIVE CLOUDS AND
COLDER BOUNDARY LAYER TEMPS.
AN IMPRESSIVELY STRONG AND EXPANSIVE SURFACE HIGH WILL STRETCH
ACROSS MUCH OF THE CENTRAL AND EASTERN UNITED STATES WEDNESDAY
AND THURSDAY. EXPECT RATHER QUIET CONDITIONS TO PREVAIL...WITH
TEMPERATURES NOT FAR FROM SEASONAL NORMAL. HIGH TEMPERATURES WILL
BE IN THE MID 50S NORTH TO NEAR 60 DEGREES SOUTH UNDER MOSTLY CLEAR
TO PARTY CLOUDY SKIES. BOTH WEDNESDAY AND THURSDAY MORNING WILL
FEATURE LOWS IN THE LOWER TO 30S INLAND TO UPPER 30S TO NEAR 40
ALONG THE U.S. 17 CORRIDOR.
&&
.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
THE EXPANSIVE SURFACE HIGH WILL STEADILY SHIFT OVER GEORGIA AND
THE CAROLINAS BY FRIDAY...BEFORE MOVING INTO THE ATLANTIC WATERS
SATURDAY. A STRONG CUT OFF LOW OVER THE DESERT SOUTHWEST FRIDAY WILL
EJECT INTO THE SOUTHERN PLAINS OVER THE WEEKEND AND THEN DAMPEN
AS IT MOVE INTO THE UPPER GULF COAST REGION BY LATE WEEKEND. CLOUDS
WILL BE ON THE INCREASE THURSDAY NIGHT AS A SHORT WAVES TRAVERSES
INTO THE REGION ATOP A LARGE SUBTROPICAL RIDGE OVER FLORIDA AND
THE CARIBBEAN. THIS DISTURBANCE MAY PRODUCE SOME SPOTTY LIGHT RAINS
ON FRIDAY BUT CERTAINLY NOT SIGNIFICANT AS PRECIP IS LIKELY TO
EVAPORATE IN DRY LAYERS BELOW 10 KFT. A SLIGHT CHANCE POP LOOKS QUITE
SUFFICIENT. STEADIER RAINS ACROSS NORTH GEORGIA AND THE WESTERN
CAROLINAS MAY BEGIN TO ANCHOR A WEDGE ON SATURDAY WITH GLOBAL
MODELS DIFFERING ON SURFACE PATTERNS. THE WEEKEND LOOKS A BIT
UNSETTLED WITH PLENTY OF CLOUDS MOST AREAS AND MAINLY LOW END CHANCE
POPS AS THE UPPER WAVE FLATTENS SIGNIFICANTLY LATE IN THE WEEKEND.
SUNDAY APPEARS TO BE THE WARMER OF THE DAYS AFTER WE TRENDED DOWN A
GOOD BIT ON TEMPS NORTHERN ZONES SATURDAY. A COLD FRONT SHOULD MOVE
OFF THE COAST EARLY NEXT WEEK.
&&
.AVIATION /07Z MONDAY THROUGH FRIDAY/...
KCHS..VSBYS ARE STEADILY LOWERING AS A COMBINATION OF RADIATION
FOG AND POSSIBLY SEA FOG AFFECTS THE TERMINAL. EXPECT CONDITIONS
TO DROP BELOW AIRPORT MINIMUMS SOON WITH VSBYS DROPPING TO 1/4SM
VV001 AND STAYING THERE THROUGH ABOUT 13-14Z. THERE MAY BE SOME
VARIABLE VSBYS THROUGH ABOUT 08Z...BUT SHOULD SETTLE WELL INTO
LIFR AFTER THAT. CONDITIONS WILL IMPROVE TO MVFR 14-16Z AND REMAIN
THERE THROUGH SUNSET. LIGHT RAIN WILL LIKELY IMPACT THE TERMINAL
21-02Z AS A COLD FRONT DROPS SOUTH. VSBYS WILL BE LIMITED TO MVFR
FOR NOW...ALTHOUGH PERIODS OF IFR ARE POSSIBLE IN POCKETS OF
HEAVIER RAINFALL. LOW CLOUDS WILL FILL BACK IN BEHIND THE FRONT
WITH IFR CIGS.
KSAV...DIFFICULT FOG FCST FOR THE TERMINAL WITH HIGH RESOLUTION
MODELS OFFERING A NUMBER OF POSSIBLE OUTCOMES. WILL CONTINUE TO
STAY SOMEWHAT CONSERVATIVE UNTIL MORE PESSIMISTIC TRENDS BECOME
APPARENT...BUT IT IS CERTAINLY POSSIBLE CONDITIONS COULD DROP BELOW
ALTERNATE MINIMUMS AND EVEN AIRPORT MINIMUMS PRIOR TO SUNRISE. FOR
NOW WILL LIMIT CONDITIONS TO 2SM BR OVC006...OR JUST ABOVE
AIRFIELD MINIMUMS. AMENDMENTS WILL BE ISSUED AS NEEDED. EXPECT MVFR
CONDITIONS TO RETURN BY 14Z. LIGHT RAIN WILL OVERSPREAD THE
TERMINAL BY 20Z AND LINGER THROUGH 03Z AS A COLD FRONT DROPS
SOUTH. EXPECT IFR CIGS TO FILL IN BEHIND THE FRONT.
EXTENDED AVIATION OUTLOOK...FLIGHT RESTRICTIONS ARE LIKELY LATE
TONIGHT AS A COLD FRONT MOVES ACROSS THE REGION. MVFR CIGS
POSSIBLE INTO THE DAY TUESDAY IN THE WAKE OF THE FRONT...VFR
CONDITIONS RETURN TUESDAY NIGHT INTO LATE WEEK.
&&
.MARINE...
TODAY...DENSE SEA FOG WILL LINGER OR MUCH OF THE DAY ACROSS THE
COASTAL WATERS. THE FOG WILL LIKELY RETREAT A BIT THROUGH THE DAY
INTO THE CORRIDOR OF COLDEST WATER LOCATION FROM THE BEACHES TO
ABOUT 5-8 NM OFFSHORE. WILL MAINTAIN THE MARINE DENSE FOG
ADVISORY FOR ALL LEGS EXCEPT THE GEORGIA OFFSHORE WATERS THROUGH
10 AM. OTHERWISE...SW WINDS AROUND 10 KT WILL PERSIST WITH
COMBINED SEAS AVERAGING 2-3 FT NEARSHORE AND 3-4 FT OFFSHORE.
TONIGHT...THE RISK FOR SEA FOG WILL LINGER THROUGH THIS EVENING
OVER THE SOUTH CAROLINA WATERS AND LATE TONIGHT FOR THE GEORGIA
NEARSHORE WATERS AS A COLD FRONT DROPS SOUTH. AS WINDS TURN NORTH
ANY SEA FOG COULD BE PUSHES TO THE SOUTH AND OFFSHORE. SW WINDS
5-10 KT WILL PREVAIL AHEAD OF THE FRONT...THEN TURNING NORTH 10 KT
WITH ITS PASSAGE. SEAS WILL 2-3 FT WILL SUBSIDE TO 1-2 FT OVER THE
NEARSHORE WATERS WITH 3-4 FT SEAS SUBSIDING TO 2-3 FT FOR THE
GEORGIA OFFSHORE LEG.
TUESDAY THROUGH FRIDAY...HIGH PRES WILL BUILD FROM THE NORTHWEST
MID WEEK AND RESIDE OVER THE WATERS BY FRIDAY. COOLER AND QUITE A
BIT DRIER AIR MOVING IN WILL SET UP SOME TIGHT THERMAL AND
MOISTURE GRADIENT TUESDAY NIGHT INTO WEDNESDAY NIGHT RESULTING IN
SOME OCCASIONAL SURGES FROM THE NORTH AND NORTHEAST. 15-20 KT FLOW
OVER THE GEORGIA WATERS ON WEDNESDAY SHOULD RESULT IN SEAS
BUILDING TO 4-6 FT BEYOND 20 NM OFFSHORE. SMALL CRAFT ADVISORY
CONDITIONS ARE POSSIBLE DURING THIS TIME. LIGHTER WINDS BY LATE
WEEK WITH WINDS AND SEAS BELOW ANY CRITERIA THRESHOLDS. A BIT TOO
EARLY TO COMMIT ON STRENGTH OF THE WEDGE THIS WEEKEND AND TIMING
THE WARM FRONT THROUGH...BUT COMPLEX LOW LEVEL MIXING ENVIRONMENTS
ARE LIKELY.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...DENSE FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR SCZ043>045-
050-052.
MARINE...DENSE FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR AMZ330-350-
352-354.
&&
$$
ST/RVT
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
325 PM CST MON DEC 29 2014
.SHORT TERM...
323 PM CST
REMAINDER OF THIS AFTERNOON AND TONIGHT...
LAKE EFFECT SNOW HAS LARGELY BEEN A NON-EVENT THIS AFTERNOON...
MAINLY DUE TO VERY DRY LOW LEVEL AIR IN PLACE OVER NERN
IL/NWRN...WITH DEWPOINTS IN THE UPPER TEENS IN SPITE OF THE NELY
FETCH OFF LAKE LAKE MICHIGAN WHERE WATER TEMPERATURES ARE STILL IN
THE MIDDLE TO UPPER 30S. THE MAIN IMPACT OF THE LAKE HAS BEEN A
BKN-OVC STRATOCU DECK MOVING OFF OF THE LAKE. HOWEVER...THERE HAS
BEEN SOME SCT LIGHT SNOW WITH THE COLD FRONT/LEADING EDGE OF THE
ARCTIC AIRMASS BUILDING ACROSS THE MISSISSIPPI VALLEY AND INTO THE
OHIO VALLEY. WHILE DEEP LAYER MOISTURE HAS BEEN MEAGER...THERE IS
JUST ENOUGH FORCING TO SQUEEZE OUT SOME ISOLD AREAS OF LIGHT
SNOW...MAINLY OVER PORTIONS OF THE AREA SOUTH OF I-80. FOR THE
OVERNIGHT HOURS...AS THE HIGH CONTINUES TO SPREAD SOUTH AND EAST
AND THE4 CENTER OF THE HIGH BUILDS INTO THE NRN PLAINS/NRN
ROCKIES...LOW LEVEL FLOW SHOULD GRADUALLY BACK THROUGH NLY TO
WNWLY. THE LONGER LAKE FETCH WHEN WINDS BECOME NLY COULD STILL
HELP BRING SOME LAKE EFFECT SNOW SHOWERS TO NWRN INDIANA...BUT
HAVE BACKED OFF ON QPF/SNOW AMOUNTS...WHILE MAINTAINING THE LIKELY
POPS...WITH THE IDEA OF A HIGH POP-LOW QPF SCENARIO. SO...STILL
THINK THERE COULD BE SOME ACCUMULATING LAKE EFFECT SNOW OVER
PORTIONS OF NWRN INDIANA NEAR THE LAKE...BUT AMOUNTS WILL LIKELY
BE LIGHT. AS THE ARCTIC AIRMASS CONTINUES TO SPREAD SOUTH AND
EAST...EXPECT LOWS TONIGHT TO DROP TO NEAR 10F OVER THE ROCKFORD
AREA...WHILE LOCATIONS EAST OF THE I-55 CORRIDOR SHOULD BE IN THE
UPPER TEENS TO LOWER 20S.
KREIN
&&
.LONG TERM...
323 PM CST
TUESDAY THROUGH MONDAY...
WHILE A COOLING TREND INITIATED BEGAN SUNDAY FOLLOWING THE PASSAGE
OF A COLD FRONT LATE SATURDAY...THE MORE SIGNIFICANT COOLING TREND
IS NOW UNDERWAY AS THE TRUE ARCTIC AIRMASS SPREADS ACROSS THE
REGION. AS OF 3PM CST MONDAY AFTERNOON...TEMPERATURES IN THE
NORTHERN PLAINS RANGED FROM THE SINGLE DIGITS ABOVE 0F TO THE SINGLE
DIGITS BELOW ZERO WITH DEWPOINTS OF -10 TO -15F. THE COLD AIR IS
STILL EXPECTED TO SPREAD ACROSS THE LOCAL AREA...BUT THE COLDEST AIR
SHOULD REMAIN TO THE WEST...OVER THE PLAINS AS THE CENTER OF THE
HIGH DROPS FROM THE NORTHERN ROCKIES TONIGHT TO THE LOWER
MISSISSIPPI VALLEY BY THURSDAY MORNING. CONDITIONS ACROSS THE AREA
SHOULD GENERALLY BE DRY THROUGH THURSDAY...WITH BELOW NORMAL
TEMPERATURES AND AMPLE SUNSHINE AS THE SFC HIGH PRESSURE BUILDS
ACROSS THE REGION. STILL ANTICIPATE THAT THE LOWEST TEMPERATURES
SHOULD BE TUESDAY NIGHT INTO WEDNESDAY MORNING AS THE SFC RIDGE AXIS
BUILDS ACROSS THE AREA. WILL CARRY MIN TEMPS FOR WEDNESDAY MORNING
IN THE SINGLE DIGITS FOR THE ENTIRE CWA...RANGING FROM ARND 3F OVER
THE ROCKFORD AREA TO 8-9F EAST OF THE I-57 CORRIDOR. THERE IS SOME
CONCERN THAT THE TEMP FORECAST MAY BE A BIT TOO LOW...CONSIDERING
WINDS SHOULD REMAIN 5-10 MPH OVERNIGHT AND THERE IS NO SNOW COVER.
HOWEVER...EVEN THOUGH THE AIRMASS WILL BE VERY DRY AND SKIES SHOULD
BE MOSTLY CLEAR...EXPECT THAT THE LOWER TEMPERATURES WILL BE MORE
DRIVEN BY ADVECTION OF COLDER AIR FROM THE CENTRAL PLAINS...WITH THE
CENTER OF A 1050MB HIGH WILL BE CENTERED ALONG THE KANSAS COLORADO
BORDER...WITH A RIDGE AXIS EXTENDING TO THE EAST ACROSS CNTRL
ILLINOIS AND INTO THE UPPER OHIO VALLEY. WITH A DIGGING TROUGH
DROPPING THROUGH SCNTRL CANADA...A MODEST WLY GRADIENT WILL BE IN
PLACE...KEEPING WINDS FROM BECMG CALM. SO...EVEN THOUGH THERE IS NO
SNOW COVER OR CALM WINDS TO ALLOW FOR STRONG RADIATIVE COOLING TO
CAUSE THE TEMPERATURES TO DROP INTO THE SINGLE DIGITS...FEEL THAT
THERE WILL BE ENOUGH ADVECTION OF COLD AIR FROM THE CNTRL PLAINS TO
BRING THE LOW TEMPERATURES. THE MAIN IMPACT OF THIS COLD AIR AND
RELATIVELY BREEZY CONDITIONS WILL BE FOR WIND CHILL READINGS TO DROP
TO -5 TO -13 ACROSS THE CWA...WHICH WOULD THE COLDEST SINCE LATE
NOVEMBER.
THE OTHER FORECAST CONCERN FOR THE EXTENDED FORECAST PERIOD WILL BE
ASSOCIATED WITH A CLOSED LOW EXPECTED TO DROP INTO THE DESERT
SOUTHWEST WEDNESDAY AND WEDNESDAY NIGHT AS A STRONG PACIFIC
SHORTWAVE DROPS DOWN THE WEST COAST. THE MODELS HAVE BEEN VERY
CONSISTENT ON THE DEVELOPMENT OF THIS FEATURE...BUT THERE IS STILL A
VARIETY OF SOLUTIONS FROM THE VARIOUS MODELS IN THE TIMING OF
EJECTING THE SYSTEM OUT OF THE SRN ROCKIES AND TRACKING ACROSS THE
SOUTHERN PLAINS AND THEN LIFTING INTO THE OHIO VALLEY. THE GFS/GEM
REMAIN ON THE FASTER END OF THE FORECAST ENVELOPE WHILE THE ECMWF IS
THE CONSISTENTLY SLOWER SOLUTION. WHILE THE SLOWER SOLUTION IS
STILL FAVORED...CONFIDENCE IS STILL LOW THAT THE EVENTUAL
PROGRESSION OF THE SYSTEM COULD STILL BE SLOWER THAN WHAT THE ECMWF
CONTINUES TO INDICATE. SO...WILL MAINTAIN THE IDEA OF A SLOWER
SOLUTION. THE MAIN TREND FOR THE SENSIBLE WEATHER FEATURES SHOULD
BE A WARMING TREND WITH MAX TEMPS REBOUNDING INTO THE 30S FOR FRIDAY
AND SATURDAY AS UPPER HEIGHTS RISE IN ADVANCE OF THE UPPER LOW
EJECTING OUT OF THE DESERT SOUTHWEST. THERE IS DECENT CONFIDENCE IN
THIS GENERAL TREND. THERE IS ALSO DECENT CONFIDENCE IN THE IDEA OF
INCREASING POPS INTO THE WEEKEND...WHICH IS SLOW THAN PREVIOUSLY
FORECAST AND IN LINE WITH A SLOWER PROGRESSION OF THE SYSTEM.
HOWEVER THERE IS RELATIVELY LOW CONFIDENCE IN TIMING AND AMOUNT OF
PCPN AS THERE IS STILL THE CHANCE FOR SOME PHASING OF THE SRN STREAM
SYSTEM WITH NRN STREAM SHORT WAVE ENERGY DROPPING OUT OF THE NRN
PLAINS AND ACROSS THE GREAT LAKES. SO...WILL LIMIT POPS TO CHANCE
LEVELS FOR NOW WITH THE TREND TO DELAY THE ONSET OF ANY PCPN INTO
LATER IN THE FORECAST PERIOD.
KREIN
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* PERIOD OF PATCHY MVFR CIGS 2000-3000 FT AGL THIS AFTERNOON.
* NORTH-NORTHEAST WINDS NEAR 12 KT THIS AFTERNOON. GRADUALLY
BECOMING NORTH-NORTHWEST LATER THIS EVENING AMD DECREASING
SLIGHTLY.
RATZER
//DISCUSSION...UPDATED 18Z...
TERMINALS REMAIN ALONG THE SOUTHEASTERN PERIPHERY OF A SPRAWLING
AREA OF HIGH PRESSURE OVER THE NORTHERN PLAINS AND UPPER MIDWEST.
COLDER AIR ON NORTHERLY WINDS WAS PRODUCING SOME MVFR STRATOCU OFF
THE LAKE FROM CHICAGO SOUTHEASTWARD...WHERE SURFACE WINDS WERE
MORE NORTH-NORTHEAST. WINDS WILL TURN MORE TO THE NORTH-NORTHWEST
LATER TONIGHT AS THE HIGH PRESSURE RIDGE SETTLES SOUTH. MVFR
CLOUDS WILL HANG IN LONGEST AT GYY WITH FLOW RIGHT OFF THE LAKE
AND THE POTENTIAL FOR SOME FLURRIES OR LIGHT LAKE-INDUCED SNOW
SHOWERS INTO TONIGHT. OTHERWISE...MDW MAY SEE A FEW FLURRIES WHILE
ORD/DPA AND RFD ARE NOT EXPECTED TO. SKIES SHOULD BECOME VFR
ACROSS THE AREA BY EVENING EXCEPT AT GYY...WHERE MVFR CONDITIONS
EXPECTED INTO TONIGHT.
NORTH-NORTHEAST WINDS AROUND 12 KT WILL BACK TO THE NORTH THIS
EVENING...AND TO THE NORTHWEST BY TUESDAY MORNING WITH SPEEDS
DECREASING SLIGHTLY FROM THIS AFTERNOONS 10+ KTS.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* MEDIUM-HIGH IN WINDS.
* MEDIUM IN TIMING OF DURATION MVFR CIGS.
RATZER
//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...
* TUESDAY NIGHT...DRY/VFR. NORTHWEST WINDS.
* WEDNESDAY AND THURSDAY...DRY/VFR. GUSTY SOUTHWESTERLY WINDS.
* FRIDAY...DRY/VFR. SOUTH TO WEST WINDS.
* SATURDAY...CHANCE OF RAIN OR SNOW. IFR POSSIBLE.
* SUNDAY...CHANCE OF SNOW. IFR POSSIBLE.
KMD
&&
.MARINE...
304 PM CST
NORTH TO NORTHWEST WINDS PERSIST ACROSS THE LAKE TONIGHT...THEN
GRADUALLY BACK SOUTHWEST BY WEDNESDAY AND INCREASE TO GALES BY
WEDNESDAY AFTERNOON OR EVENING. IT IS NOT CERTAIN HOW EFFECTIVELY
THESE SOMEWHAT MILDER SOUTHWEST WINDS WILL SUPPORT STRONG GALES
OVER THE COLD WATER...BUT GALES DO APPEAR LIKELY. UNTIL WINDS TURN
AWAY FROM NORTH AND NORTHWEST...CONDITIONS WILL BE FAVORABLE FOR
SMALL CRAFT HEADLINES FOR THE FIRST HALF OF THE WEEK...AND
ESPECIALLY IN THE INDIANA NEARSHORE WATERS.
LENNING
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
315 PM CST Mon Dec 29 2014
.SHORT TERM...(Tonight)
ISSUED AT 315 PM CST MON DEC 29 2014
The 18Z surface analysis indicated the leading edge of the Arctic
airmass, ahead of an intense high pressure center in the Canadian
Rockies, was sinking just south of I-80. Clouds associated with cold
air undercutting were along the I-74 corridor at 20z/2 pm CST. This
area of cloudiness, along with low clouds in southern Iowa/northern
Missouri will overspread central and eventually southeast Illinois
this evening.
There should be enough weak forcing for snow flurries, particularly
in central Illinois this evening, and the rest of the forecast area
late tonight as the short range models point to weak lift just
behind the strongest low level cold advection. The HRRR model is
trying to produce some measurable snow from Bloomington to near
Taylorville between 6 pm and Midnight. At this point, it is the only
model, doing this and has most likely latched on to the area of
light snow around Pontiac. Will keep an eye on this, but for now
will stick to the mention of flurries.
The numerical guidance appears to be on the colder side due to less
cloud cover and stronger cold advection. Thus, will be going with
lows roughly 5 degrees warmer than guidance in central IL and 2-3
degrees warmer in southeast IL due to forecast cloud cover.
&&
.LONG TERM...(Tuesday through Monday)
ISSUED AT 315 PM CST MON DEC 29 2014
The narrow band of flurries will continue into Tuesday morning, but
should dissipate by afternoon. Behind this area, and strong 1050mb
high pressure area will drop into the region. This high will bring
dry weather to the area through Thur night, as well as well below
normal temps through the period. With the center of the high
dropping into the plains Tue night, the coldest temps are expected
to be Tue night through Wed. Northwesterly winds Tue night will
still be around 10mph, so there could be enough mixing to prevent
the bottom from dropping out on the temps. However, single digits
are still expected over half of the CWA, and combined with the wind
speeds, below zero wind chills are probably Tue night/Wed morning.
Beyond this, the high pressure will slide further south into the
southern plains by Thursday night. Temps may warm slightly, but only
to back around normal.
The return of slightly warmer temps and moisture will not occur
until the high pressure area move into the southeastern US Thur
night and Fri. However, along with this will come the chance of pcpn
to the area for the end of the week and the weekend. The questions
still remain as to the timing of the pcpn return, how warm it will
get, and what p-type will occur. Both the GFS and ECMWF continue to
not agree on the overall solution with this system. However, there
is some agreement as to how the upper level will evolve into
Saturday. The upper level low pressure area will weaken and get
lifted out into the flow over the weekend. ECMWF is much quicker
with this than the GFS. Models also agree that the pcpn will not
really begin until Fri night/Sat morning. However, there still
remains a chance of pcpn Friday in the southeast, so will keep
chance pops there, though would not be surprised to see this change
later. Beyond this, models do not agree with location of pcpn and
sfc low pressure area. With the ECMWF being quicker with the upper
level system, it keeps the low further south and therefore has very
little pcpn in our area...and only in the extreme southeast. The GFS
is further north with the low, but has shifted it east since
yesterday`s model runs. However, it keeps pcpn over the area through
the weekend, just not as much as before; and with the low east,
temps may not get as warm, thereby effecting the p-type through the
weekend. Will still be keeping the p-type simple and just going with
snow, becoming rain or snow, then snow at night and rain and/or snow
again during the daytime. The chance of pcpn will continue into Sat
night. Sunday and Monday will be dry for now as the system should be
well east of the area.
Temps in the extended will warm, with the warmest temps being on
Saturday and then cooling back off by Monday as another shot of
colder air slides into the area.
&&
.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
ISSUED AT 1158 AM CST MON DEC 29 2014
The leading edge of an Arctic boundary will gradually bring MVFR
ceilings into central Illinois this evening. However, in the
meantime, will be keeping an eye on low clouds advancing from the
northeast, due to NNE fetch off of Lake Michigan. For now it looks
like scattered cumulus can be expected at the TAF sites from KPIA
to KCMI this afternoon. However, there is a potential for a brief period
of MVFR ceilings this afternoon from KBMI to KCMI, but confidence
is low at this time.
As the Arctic airmass approaches this evening, MVFR ceilings
upstream will spread into central Illinois in the 00 to 03Z time
frame. There will be just enough low level forcing for periods of
light snow/flurries tonight. Many of the short range models are
indicating no accumulation with this light snow, however the NAM
is pointing to the development of very minor accumulations in east
central IL just before daybreak. For now, will only have the
ceilings at MVFR levels and keep visibility unrestricted, but will
need to watch this with future model runs and TAF issuances.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Miller
LONG TERM...Auten
AVIATION...Miller
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
154 PM CST MON DEC 29 2014
.SHORT TERM...
220 AM CST
THROUGH TUESDAY...
PRIMARY FORECAST CHALLENGE IN THE SHORT TERM IS WITH LAKE EFFECT
POTENTIAL THROUGH TONIGHT. DESPITE MODERATELY COLD AIR MASS IN PLACE
LAKE EFFECT THUS FAR TONIGHT HAS BEEN ABSENT AND THERMODYNAMICS ARE
NOT EXPECTED TO IMPROVE THIS MORNING SO PLAN TO JUST HOLD ON TO
SLIGHT CHANCE OF SNOW SHOWERS AND CHANCE OF FLURRIES ALONG THE
ILLINOIS LAKE SHORE THIS MORNING. BEST HOPE OF LAKE EFFECT SNOW
SHOWERS/FLURRIES THIS MORNING WILL HINGE ON MID LEVEL CLOUDINESS
BEGINNING TO SPREAD IN ACTUALLY SEEDING THE LAKE STRATOCUMULUS.
LOW LEVEL FLOW WILL GRADUALLY BACK TO NORTH THIS AFTERNOON THEN
NORTH-NORTHWEST WITH THE RESULTANT LAKE EFFECT POTENTIAL PIVOTING
AROUND THE SOUTH RIM OF LAKE MICHIGAN THROUGH TONIGHT.
THERMODYNAMICS COULD IMPROVE SLIGHTLY THIS AFTERNOON...THOUGH
GETTING INTO A DIURNALLY UNFAVORABLE TIME OF DAY CONSIDERING THE
STILL MARGINAL SET UP FOR LAKE EFFECT SNOW TO GET CRANKING THIS
AFTERNOON. PLAN TO JUST GRADUALLY SHIFT FLURRIES/SMALL SNOW SHOWERS
CHANCES EAST FOCUSING MORE INTO NW INDY AND EXTREME SE COOK THIS
AFTERNOON.
MORE FAVORABLE THERMODYNAMIC ENVIRONMENT WILL DEVELOP THIS EVENING
AND CONTINUE OVERNIGHT WITH IMPROVED INSTABILITY AND SLIGHTLY HIGHER
INVERSION HEIGHTS. WILL MAINTAIN HIGH CHANCE/LOW END LIKELY POPS
NEAR THE LAKE TONIGHT BUT ACCUMULATIONS WILL PROBABLY BE PRETTY
MINOR BECAUSE AS THERMAL INSTABILITY INCREASES...MODELS ALSO PROG
INCREASINGLY DRY AIR TO SPREAD IN JUST ABOVE THE BOUNDARY LAYER
INVERSION WHICH GIVEN THE MARGINAL TEMPS IN THE CLOUD BARING LAYER
REALLY DOES NOT BODE WELL FOR EFFICIENTLY ACCUMULATING SNOW. CURRENT
THINKING IS NO ACCUMULATION IN NE IL AND MOSTLY LESS THAN AN INCH IN
NW INDY TONIGHT...THOUGH ISOLATED AMOUNTS OF 1 TO POSSIBLY UP TO 2
INCHES WOULD BE ON THE HIGH SIDE. LAKE EFFECT THREAT WILL SHIFT EAST
OUT OF THE CWA TUESDAY AND SHOULD SEE CLOUDS CLEAR OUT AND SKIES
BECOME SUNNY...BUT THE SUNSHINE WILL BE MORE FOR SHOW THAN ANYTHING
ELSE AS TEMPS STRUGGLE TO REACH 20F.
IZZI
&&
.LONG TERM...
220 AM CST
TUESDAY NIGHT THROUGH SUNDAY...
COLD AIR MASS WILL REMAIN ENTRENCHED WEDNESDAY BUT MAGNITUDE OF THE
COLD WILL NO DOUBT BE TEMPERED BY THE LACK OF SNOW COVER HERE OR
EVEN FAR UPSTREAM...SO WHILE IT WILL BE COLD HAVE GONE WITH TEMPS A
BIT ABOVE WHAT 850MB/925MB CLIMO WOULD SUPPORT. WARM ADVECTION
BEGINS WEDNESDAY NIGHT AND REALLY CRANKS INTO GEAR THURSDAY ALLOWING
FOR A NICE REBOUND IN TEMPS...THOUGH THE WARMING WILL BE MORE
ACADEMIC THAN ACTUALLY FELT AS GUSTY SOUTHWEST WINDS PRODUCE STILL
CHILLY WIND CHILLS THURSDAY. TEMPS SHOULD CONTINUE TO MODERATE ON
FRIDAY WITH PRECIPITATION LOOKING PRETTY UNLIKELY FRIDAY.
STRONG TROUGH WILL TO DIG INTO THE DESERT SOUTHWEST NEW YEARS EVE
AND IS FORECAST TO PRODUCE ACCUMULATING SNOW ON THE LAS VEGAS STRIP
NEW YEARS EVE WHERE WINTER STORM WATCHES ARE IN EFFECT! THIS
POWERFUL SYSTEM IS PROGGED TO CLOSE OFF A LARGE DEEP CIRCULATION
THAT BECOMES CUT OFF FROM THE WESTERLIES. A SET UP LIKE THIS MORE
OFTEN THAN NOT SPELLS BIG TROUBLES FOR PREDICTABILITY IN THE MEDIUM
RANGE AS THIS SYSTEM WILL PRESENT A COUPLE OF THE THINGS THAT MODELS
STRUGGLE WITH...FIRST HANDLING TRACK/TIMING OF EJECTING SOUTHWEST
CUT OFFS AND SECOND THE POTENTIAL FOR PHASING WITH NORTHERN STREAM
SHORTWAVE ENERGY.
THE RANGE OF POSSIBILITIES FOR THE WEEKEND IN OUR AREA TRULY RUN THE
GAMUT FROM DRY CONDITIONS ALL WEEKEND TO RAIN...ACCUMULATING
SNOW...A WINTRY MIX...OR SOME COMBINATION OF THE ABOVE. THE
OPERATIONAL GFS IS MOST GUNG-HO WITH PHASING AND FASTEST EJECTING
THE LOW EASTWARD...WHICH WOULD SEEM TO COUNTER WHAT IS TYPICAL IN
THESE SCENARIOS. THE PARALLEL GFS AND ECMWF ARE BOTH SOUTH AND
SLOWER WITH THE SYSTEM AND WOULD LEAD TO A DRY WEEKEND IN OUR AREA.
THE BLENDED MODEL POPS FOR THE WEEKEND HAVE COME DOWN FROM PREVIOUS
CYCLES AND AM NOT PLANNING ANY CHANGES TO THEM AS PREDICTABILITY IS
JUST TOO LOW AT THIS POINT. AT THIS POINT THE CHANCES OF THE LAS
VEGAS STRIP SEEING MORE ACCUMULATING SNOW THE NEXT 7 DAYS IS
CURRENTLY HIGHER THAN HERE IN OUR CWA...QUITE ATYPICAL AND
DEFINITELY NOT SOMETHING THAT ONE WOULD TYPICALLY WAGER WOULD BE
THE CASE!
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* PERIOD OF PATCHY MVFR CIGS 2000-3000 FT AGL THIS AFTERNOON.
* NORTH-NORTHEAST WINDS NEAR 12 KT THIS AFTERNOON. GRADUALLY
BECOMING NORTH-NORTHWEST LATER THIS EVENING AMD DECREASING
SLIGHTLY.
RATZER
//DISCUSSION...UPDATED 18Z...
TERMINALS REMAIN ALONG THE SOUTHEASTERN PERIPHERY OF A SPRAWLING
AREA OF HIGH PRESSURE OVER THE NORTHERN PLAINS AND UPPER MIDWEST.
COLDER AIR ON NORTHERLY WINDS WAS PRODUCING SOME MVFR STRATOCU OFF
THE LAKE FROM CHICAGO SOUTHEASTWARD...WHERE SURFACE WINDS WERE
MORE NORTH-NORTHEAST. WINDS WILL TURN MORE TO THE NORTH-NORTHWEST
LATER TONIGHT AS THE HIGH PRESSURE RIDGE SETTLES SOUTH. MVFR
CLOUDS WILL HANG IN LONGEST AT GYY WITH FLOW RIGHT OFF THE LAKE
AND THE POTENTIAL FOR SOME FLURRIES OR LIGHT LAKE-INDUCED SNOW
SHOWERS INTO TONIGHT. OTHERWISE...MDW MAY SEE A FEW FLURRIES WHILE
ORD/DPA AND RFD ARE NOT EXPECTED TO. SKIES SHOULD BECOME VFR
ACROSS THE AREA BY EVENING EXCEPT AT GYY...WHERE MVFR CONDITIONS
EXPECTED INTO TONIGHT.
NORTH-NORTHEAST WINDS AROUND 12 KT WILL BACK TO THE NORTH THIS
EVENING...AND TO THE NORTHWEST BY TUESDAY MORNING WITH SPEEDS
DECREASING SLIGHTLY FROM THIS AFTERNOONS 10+ KTS.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* MEDIUM-HIGH IN WINDS.
* MEDIUM IN TIMING OF DURATION MVFR CIGS.
RATZER
//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...
* TUESDAY NIGHT...DRY/VFR. NORTHWEST WINDS.
* WEDNESDAY AND THURSDAY...DRY/VFR. GUSTY SOUTHWESTERLY WINDS.
* FRIDAY...DRY/VFR. SOUTH TO WEST WINDS.
* SATURDAY...CHANCE OF RAIN OR SNOW. IFR POSSIBLE.
* SUNDAY...CHANCE OF SNOW. IFR POSSIBLE.
KMD
&&
.MARINE...
247 AM CST
A COLD FRONT WILL CLEAR THE SOUTH END OF THE LAKE LATER THIS MORNING
AS STRONG HIGH PRESSURE IN NORTHWEST CANADA BEGINS TO BUILD SOUTH
INTO THE CENTRAL PLAINS. AS THE HIGH CONTINUES TO SLIDE INTO THE
PLAINS...LOW PRESSURE WILL TRACK SOUTHEAST THROUGH HUDSON BAY.
EXPECT A DECENT GRADIENT TO SETUP BETWEEN THESE TWO STRONG FEATURES.
THIS WILL CREATE A PERIOD OF GALES OVER THE LAKE WEDNESDAY AND
WEDNESDAY EVENING. THE HIGH WILL THEN SHIFT INTO THE TENNESSEE
VALLEY AND WEAKEN WHILE THE HUDSON BAY LOW RETREATS INTO THE
CANADIAN MARTIMES ON FRIDAY.
KMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1159 AM CST Mon Dec 29 2014
.UPDATE...
ISSUED AT 1042 AM CST MON DEC 29 2014
No major changes made to the forecast late this morning, just
tweaked the high temperatures down a few degrees for today,
particularly in southeast Illinois.
Still looking for a gradual increase in cloudiness, especially
along and west of the Illinois River Valley this afternoon. The
latest satellite loop indicated the leading edge of Arctic air and
lower clouds/flurries just moving into northwest IL, extending
west-southwest toward extreme northern Missouri. The HRRR and to a
certain extent the RAP are a bit too quick with the advancement of
the clouds into central IL, so will stick with the gradual
increase.
Despite plenty of sunshine, temperatures are climbing a bit slower
than previously thought. Thus, shaved high temperatures a few
degrees, with mid 30s anticipated across central and eastern IL
with upper 30s south of I-70.
Will maintain the mention of flurries for tonight across the
forecast area, but a preliminary look at the updated models are
indicating they may be confined to areas in west central and
central IL.
&&
.SHORT TERM...(This afternoon through tonight)
ISSUED AT 1147 AM CST MON DEC 29 2014
08z/2am surface analysis shows strong 1057mb high over northern
British Columbia/Alberta. Bitterly cold airmass beneath the high
with current temps in the teens and 20s below zero is building
southward into the Northern Plains/Upper Midwest, with the leading
edge of the colder air sinking toward northern Illinois. Front will
remain north of the KILX CWA today: however, increasing mid/high
clouds in the vicinity of the boundary will be noted across the
north. End result will be partly to mostly cloudy skies north of
Peoria, with mostly sunny skies further south across the remainder
of the area. High temperatures will once again be near normal for
this time of year in the middle to upper 30s.
&&
.LONG TERM...(Tuesday through Sunday)
ISSUED AT 1147 AM CST MON DEC 29 2014
Main weather story this week will be the shot of very cold air
expected Tuesday through Thursday. Arctic cold front will settle
southward into central Illinois tonight, accompanied by clouds and
perhaps a few flurries. NAM time-height cross-sections show much
shallower moisture profiles and weaker lift than they did on
previous runs: however, think strong CAA will be enough to produce
scattered flurries overnight. Any flurries will come to an end
Tuesday morning as high pressure builds into the region and skies
gradually clear. High temperatures will be much colder than today,
ranging from the lower 20s northwest to the lower 30s south of
I-70. Heart of the coldest airmass will arrive Tuesday night into
Wednesday. Thanks to clear skies and diminishing winds, low
temperatures Tuesday night will bottom out in the single digits and
teens, with corresponding wind-chill readings dropping below zero.
Despite full sunshine, highs on Wednesday will struggle to reach the
lower to middle 20s. As high pressure sinks south of the region,
winds will back to the southwest and help boost temps back into the
lower 30s by Thursday.
Forecast becomes more complicated later in the week, as a southern
stream system slowly approaches from the southwest. Model-to-model
as well as run-to-run consistency remains poor, so forecast
confidence beyond Thursday is low. Latest trend observed with the
00z Dec 29 model suite suggests a deeper cut-off low over the Desert
Southwest and thus a slower northeastward ejection. Current water
vapor imagery shows a strong jet streak diving southward along the
west coast of the US, which is progged to carve out a closed upper
low over California within the next 48 hours. Models are in very
good agreement initially, showing the low meandering slowly eastward
to the Texas/Oklahoma panhandles by Saturday evening: however, they
have very different ideas on how to handle precip ahead of the
system. The ECMWF shows precip breaking out well in advance of the
low across the southern Plains Thursday, then spreading
northeastward into south-central Illinois and the Ohio River Valley
late Thursday night into Friday. Given presence of cold/dry airmass
across the region, am very skeptical about this aggressive push of
precip. As a result, will continue with a dry forecast Thursday
night and will reduce PoPs significantly during the day Friday. The
GFS seems to have a much more realistic solution, showing precip
remaining south of Illinois until Friday night into Saturday.
Models are in poor agreement with what happens to the southwest
system over the weekend, with the ECMWF maintaining a closed 500mb
low longer than the GFS, which opens the wave and allows it to be
absorbed into the northern stream much faster. If the ECMWF
verifies, much of the precip associated with the low will remain
southeast of Illinois across the Ohio River Valley. This is a
drastic change from its previous runs, so am looking at this with a
great deal of skepticism. Prefer the more consistent GFS, which
opens the low and brings it northward into the area on Saturday. As
a result, have introduced chance PoPs across the board Friday
night/Saturday, then have ended precip chances by Sunday as the
system exits into the Great Lakes. Precip type will be an issue as
well, with forecast soundings and surface temps initially supporting
snow or a rain/snow mix. Atmosphere will likely warm enough to
change the precip to mostly rain on Saturday before colder air
returns Saturday night into Sunday. Overall this does not like a
major winter storm for central Illinois, but future model runs will
need to be monitored for any potential changes.
&&
.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
ISSUED AT 1158 AM CST MON DEC 29 2014
The leading edge of an Arctic boundary will gradually bring MVFR
ceilings into central Illinois this evening. However, in the
meantime, will be keeping an eye on low clouds advancing from the
northeast, due to NNE fetch off of Lake Michigan. For now it looks
like scattered cumulus can be expected at the TAF sites from KPIA
to KCMI this afternoon. However, there is a potential for a brief period
of MVFR ceilings this afternoon from KBMI to KCMI, but confidence
is low at this time.
As the Arctic airmass approaches this evening, MVFR ceilings
upstream will spread into central Illinois in the 00 to 03Z time
frame. There will be just enough low level forcing for periods of
light snow/flurries tonight. Many of the short range models are
indicating no accumulation with this light snow, however the NAM
is pointing to the development of very minor accumulations in east
central IL just before daybreak. For now, will only have the
ceilings at MVFR levels and keep visibility unrestricted, but will
need to watch this with future model runs and TAF issuances.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Miller
SHORT TERM...Barnes
LONG TERM...Barnes
AVIATION...Miller
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1133 AM CST MON DEC 29 2014
.SHORT TERM...
220 AM CST
THROUGH TUESDAY...
PRIMARY FORECAST CHALLENGE IN THE SHORT TERM IS WITH LAKE EFFECT
POTENTIAL THROUGH TONIGHT. DESPITE MODERATELY COLD AIR MASS IN PLACE
LAKE EFFECT THUS FAR TONIGHT HAS BEEN ABSENT AND THERMODYNAMICS ARE
NOT EXPECTED TO IMPROVE THIS MORNING SO PLAN TO JUST HOLD ON TO
SLIGHT CHANCE OF SNOW SHOWERS AND CHANCE OF FLURRIES ALONG THE
ILLINOIS LAKE SHORE THIS MORNING. BEST HOPE OF LAKE EFFECT SNOW
SHOWERS/FLURRIES THIS MORNING WILL HINGE ON MID LEVEL CLOUDINESS
BEGINNING TO SPREAD IN ACTUALLY SEEDING THE LAKE STRATOCUMULUS.
LOW LEVEL FLOW WILL GRADUALLY BACK TO NORTH THIS AFTERNOON THEN
NORTH-NORTHWEST WITH THE RESULTANT LAKE EFFECT POTENTIAL PIVOTING
AROUND THE SOUTH RIM OF LAKE MICHIGAN THROUGH TONIGHT.
THERMODYNAMICS COULD IMPROVE SLIGHTLY THIS AFTERNOON...THOUGH
GETTING INTO A DIURNALLY UNFAVORABLE TIME OF DAY CONSIDERING THE
STILL MARGINAL SET UP FOR LAKE EFFECT SNOW TO GET CRANKING THIS
AFTERNOON. PLAN TO JUST GRADUALLY SHIFT FLURRIES/SMALL SNOW SHOWERS
CHANCES EAST FOCUSING MORE INTO NW INDY AND EXTREME SE COOK THIS
AFTERNOON.
MORE FAVORABLE THERMODYNAMIC ENVIRONMENT WILL DEVELOP THIS EVENING
AND CONTINUE OVERNIGHT WITH IMPROVED INSTABILITY AND SLIGHTLY HIGHER
INVERSION HEIGHTS. WILL MAINTAIN HIGH CHANCE/LOW END LIKELY POPS
NEAR THE LAKE TONIGHT BUT ACCUMULATIONS WILL PROBABLY BE PRETTY
MINOR BECAUSE AS THERMAL INSTABILITY INCREASES...MODELS ALSO PROG
INCREASINGLY DRY AIR TO SPREAD IN JUST ABOVE THE BOUNDARY LAYER
INVERSION WHICH GIVEN THE MARGINAL TEMPS IN THE CLOUD BARING LAYER
REALLY DOES NOT BODE WELL FOR EFFICIENTLY ACCUMULATING SNOW. CURRENT
THINKING IS NO ACCUMULATION IN NE IL AND MOSTLY LESS THAN AN INCH IN
NW INDY TONIGHT...THOUGH ISOLATED AMOUNTS OF 1 TO POSSIBLY UP TO 2
INCHES WOULD BE ON THE HIGH SIDE. LAKE EFFECT THREAT WILL SHIFT EAST
OUT OF THE CWA TUESDAY AND SHOULD SEE CLOUDS CLEAR OUT AND SKIES
BECOME SUNNY...BUT THE SUNSHINE WILL BE MORE FOR SHOW THAN ANYTHING
ELSE AS TEMPS STRUGGLE TO REACH 20F.
IZZI
&&
.LONG TERM...
220 AM CST
TUESDAY NIGHT THROUGH SUNDAY...
COLD AIR MASS WILL REMAIN ENTRENCHED WEDNESDAY BUT MAGNITUDE OF THE
COLD WILL NO DOUBT BE TEMPERED BY THE LACK OF SNOW COVER HERE OR
EVEN FAR UPSTREAM...SO WHILE IT WILL BE COLD HAVE GONE WITH TEMPS A
BIT ABOVE WHAT 850MB/925MB CLIMO WOULD SUPPORT. WARM ADVECTION
BEGINS WEDNESDAY NIGHT AND REALLY CRANKS INTO GEAR THURSDAY ALLOWING
FOR A NICE REBOUND IN TEMPS...THOUGH THE WARMING WILL BE MORE
ACADEMIC THAN ACTUALLY FELT AS GUSTY SOUTHWEST WINDS PRODUCE STILL
CHILLY WIND CHILLS THURSDAY. TEMPS SHOULD CONTINUE TO MODERATE ON
FRIDAY WITH PRECIPITATION LOOKING PRETTY UNLIKELY FRIDAY.
STRONG TROUGH WILL TO DIG INTO THE DESERT SOUTHWEST NEW YEARS EVE
AND IS FORECAST TO PRODUCE ACCUMULATING SNOW ON THE LAS VEGAS STRIP
NEW YEARS EVE WHERE WINTER STORM WATCHES ARE IN EFFECT! THIS
POWERFUL SYSTEM IS PROGGED TO CLOSE OFF A LARGE DEEP CIRCULATION
THAT BECOMES CUT OFF FROM THE WESTERLIES. A SET UP LIKE THIS MORE
OFTEN THAN NOT SPELLS BIG TROUBLES FOR PREDICTABILITY IN THE MEDIUM
RANGE AS THIS SYSTEM WILL PRESENT A COUPLE OF THE THINGS THAT MODELS
STRUGGLE WITH...FIRST HANDLING TRACK/TIMING OF EJECTING SOUTHWEST
CUT OFFS AND SECOND THE POTENTIAL FOR PHASING WITH NORTHERN STREAM
SHORTWAVE ENERGY.
THE RANGE OF POSSIBILITIES FOR THE WEEKEND IN OUR AREA TRULY RUN THE
GAMUT FROM DRY CONDITIONS ALL WEEKEND TO RAIN...ACCUMULATING
SNOW...A WINTRY MIX...OR SOME COMBINATION OF THE ABOVE. THE
OPERATIONAL GFS IS MOST GUNG-HO WITH PHASING AND FASTEST EJECTING
THE LOW EASTWARD...WHICH WOULD SEEM TO COUNTER WHAT IS TYPICAL IN
THESE SCENARIOS. THE PARALLEL GFS AND ECMWF ARE BOTH SOUTH AND
SLOWER WITH THE SYSTEM AND WOULD LEAD TO A DRY WEEKEND IN OUR AREA.
THE BLENDED MODEL POPS FOR THE WEEKEND HAVE COME DOWN FROM PREVIOUS
CYCLES AND AM NOT PLANNING ANY CHANGES TO THEM AS PREDICTABILITY IS
JUST TOO LOW AT THIS POINT. AT THIS POINT THE CHANCES OF THE LAS
VEGAS STRIP SEEING MORE ACCUMULATING SNOW THE NEXT 7 DAYS IS
CURRENTLY HIGHER THAN HERE IN OUR CWA...QUITE ATYPICAL AND
DEFINITELY NOT SOMETHING THAT ONE WOULD TYPICALLY WAGER WOULD BE
THE CASE!
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* PERIOD OF PATCHY MVFR CIGS 2000-3000 FT AGL THIS AFTERNOON.
* A FEW FLURRIES POSSIBLE ESPECIALLY AT MDW...THOUGH NOT EXPECTED
TO RESTRICT VSBY OR ACCUMULATE.
* NORTH-NORTHEAST WINDS NEAR 12 KT THIS AFTERNOON. GRADUALLY
BECOMING NORTH-NORTHWEST LATER THIS EVENING AMD DECREASING
SLIGHTLY.
RATZER
//DISCUSSION...UPDATED 18Z...
TERMINALS REMAIN ALONG THE SOUTHEASTERN PERIPHERY OF A SPRAWLING
AREA OF HIGH PRESSURE OVER THE NORTHERN PLAINS AND UPPER MIDWEST.
COLDER AIR ON NORTHERLY WINDS WAS PRODUCING SOME MVFR STRATOCU OFF
THE LAKE FROM CHICAGO SOUTHEASTWARD...WHERE SURFACE WINDS WERE
MORE NORTH-NORTHEAST. WINDS WILL TURN MORE TO THE NORTH-NORTHWEST
LATER TONIGHT AS THE HIGH PRESSURE RIDGE SETTLES SOUTH. MVFR
CLOUDS WILL HANG IN LONGEST AT GYY WITH FLOW RIGHT OFF THE LAKE
AND THE POTENTIAL FOR SOME FLURRIES OR LIGHT LAKE-INDUCED SNOW
SHOWERS INTO TONIGHT. OTHERWISE...MDW MAY SEE A FEW FLURRIES WHILE
ORD/DPA AND RFD ARE NOT EXPECTED TO. SKIES SHOULD BECOME VFR
ACROSS THE AREA BY EVENING EXCEPT AT GYY...WHERE MVFR CONDITIONS
EXPECTED INTO TONIGHT.
NORTH-NORTHEAST WINDS AROUND 12 KT WILL BACK TO THE NORTH THIS
EVENING...AND TO THE NORTHWEST BY TUESDAY MORNING WITH SPEEDS
DECREASING SLIGHTLY FROM THIS AFTERNOONS 10+ KTS.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* MEDIUM-HIGH IN WINDS.
* MEDIUM IN TIMING OF DURATION MVFR CIGS.
RATZER
//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...
* TUESDAY NIGHT...DRY/VFR. NORTHWEST WINDS.
* WEDNESDAY AND THURSDAY...DRY/VFR. GUSTY SOUTHWESTERLY WINDS.
* FRIDAY...DRY/VFR. SOUTH TO WEST WINDS.
* SATURDAY...CHANCE OF RAIN OR SNOW. IFR POSSIBLE.
* SUNDAY...CHANCE OF SNOW. IFR POSSIBLE.
KMD
&&
.MARINE...
247 AM CST
A COLD FRONT WILL CLEAR THE SOUTH END OF THE LAKE LATER THIS MORNING
AS STRONG HIGH PRESSURE IN NORTHWEST CANADA BEGINS TO BUILD SOUTH
INTO THE CENTRAL PLAINS. AS THE HIGH CONTINUES TO SLIDE INTO THE
PLAINS...LOW PRESSURE WILL TRACK SOUTHEAST THROUGH HUDSON BAY.
EXPECT A DECENT GRADIENT TO SETUP BETWEEN THESE TWO STRONG FEATURES.
THIS WILL CREATE A PERIOD OF GALES OVER THE LAKE WEDNESDAY AND
WEDNESDAY EVENING. THE HIGH WILL THEN SHIFT INTO THE TENNESSEE
VALLEY AND WEAKEN WHILE THE HUDSON BAY LOW RETREATS INTO THE
CANADIAN MARTIMES ON FRIDAY.
KMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1043 AM CST Mon Dec 29 2014
.SHORT TERM...(This afternoon through tonight)
ISSUED AT 1042 AM CST MON DEC 29 2014
No major changes made to the forecast late this morning, just
tweaked the high temperatures down a few degrees for today,
particularly in southeast Illinois.
Still looking for a gradual increase in cloudiness, especially
along and west of the Illinois River Valley this afternoon. The
latest satellite loop indicated the leading edge of Arctic air and
lower clouds/flurries just moving into northwest IL, extending
west-southwest toward extreme northern Missouri. The HRRR and to a
certain extent the RAP are a bit too quick with the advancement of
the clouds into central IL, so will stick with the gradual
increase.
Despite plenty of sunshine, temperatures are climbing a bit slower
than previously thought. Thus, shaved high temperatures a few
degrees, with mid 30s anticipated across central and eastern IL
with upper 30s south of I-70.
Will maintain the mention of flurries for tonight across the
forecast area, but a preliminary look at the updated models are
indicating they may be confined to areas in west central and
central IL.
&&
.LONG TERM...(Tonight through Sunday)
ISSUED AT 308 AM CST MON DEC 29 2014
Main weather story this week will be the shot of very cold air
expected Tuesday through Thursday. Arctic cold front will settle
southward into central Illinois tonight, accompanied by clouds and
perhaps a few flurries. NAM time-height cross-sections show much
shallower moisture profiles and weaker lift than they did on
previous runs: however, think strong CAA will still be enough to
produce scattered flurries overnight. Any flurries will come to
an end Tuesday morning as high pressure builds into the region and
skies gradually clear. High temperatures will be much colder than
today, ranging from the lower 20s northwest to the lower 30s south
of I-70. Heart of the coldest airmass will arrive Tuesday night
into Wednesday. Thanks to clear skies and diminishing winds, low
temperatures Tuesday night will bottom out in the single digits
and teens, with corresponding wind-chill readings dropping below
zero. Despite full sunshine, highs on Wednesday will struggle to
reach the lower to middle 20s. As high pressure sinks south of
the region, winds will back to the southwest and help boost temps
back into the lower 30s by Thursday.
Forecast becomes more complicated later in the week, as a southern
stream system slowly approaches from the southwest. Model-to-model
as well as run-to-run consistency remains poor, so forecast
confidence beyond Thursday is low. Latest trend observed with the
00z Dec 29 model suite suggests a deeper cut-off low over the Desert
Southwest and thus a slower northeastward ejection. Current water
vapor imagery shows a strong jet streak diving southward along the
West Coast, which is progged to carve out a closed upper low over
California within the next 48 hours. Models are in very good
agreement initially, showing the low meandering slowly eastward to
the Texas/Oklahoma panhandles by Saturday evening: however, they
have very different ideas on how to handle precip ahead of the
system. The ECMWF shows precip breaking out well in advance of
the low across the southern Plains Thursday, then spreading
northeastward into south-central Illinois and the Ohio River
Valley late Thursday night into Friday. Given presence of
cold/dry airmass across the region, am very skeptical about this
aggressive push of precip. As a result, will continue with a dry
forecast Thursday night and will reduce PoPs significantly during
the day Friday. The GFS seems to have a much more realistic
solution, showing precip remaining south of Illinois until Friday
night into Saturday. Models are in poor agreement with what
happens to the southwest system over the weekend, with the ECMWF
maintaining a closed 500mb low longer than the GFS, which opens
the wave and allows it to be absorbed into the northern stream
much faster. If the ECMWF verifies, much of the precip associated
with the low will remain southeast of Illinois across the Ohio
River Valley. This is a drastic change from its previous runs, so
am looking at this with a great deal of skepticism. Prefer the
more consistent GFS, which opens the low and brings it northward
into the area on Saturday. As a result, have introduced chance
PoPs across the board Friday night/Saturday, then have ended
precip chances by Sunday as the system exits into the Great Lakes.
Precip type will be an issue as well, with forecast soundings and
surface temps initially supporting snow or a rain/snow mix.
Atmosphere will likely warm enough to change the precip to mostly
rain on Saturday before colder air returns Saturday night into
Sunday. Overall this does not look like a major winter storm for
central Illinois, but future model runs will need to be monitored
for any potential changes.
&&
.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
ISSUED AT 546 AM CST MON DEC 29 2014
An arctic cold will slip south of the central Illinois terminals
today. VFR conditions for much of today will eventually fall to
MVFR this evening as an area of low level moisture spills in from
the north along with the colder air. A few flurries are possible
as the low clouds return, but no significant snow is anticipated.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Miller
LONG TERM...Barnes
AVIATION...Bak
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
532 AM CST MON DEC 29 2014
.SHORT TERM...
220 AM CST
THROUGH TUESDAY...
PRIMARY FORECAST CHALLENGE IN THE SHORT TERM IS WITH LAKE EFFECT
POTENTIAL THROUGH TONIGHT. DESPITE MODERATELY COLD AIR MASS IN PLACE
LAKE EFFECT THUS FAR TONIGHT HAS BEEN ABSENT AND THERMODYNAMICS ARE
NOT EXPECTED TO IMPROVE THIS MORNING SO PLAN TO JUST HOLD ON TO
SLIGHT CHANCE OF SNOW SHOWERS AND CHANCE OF FLURRIES ALONG THE
ILLINOIS LAKE SHORE THIS MORNING. BEST HOPE OF LAKE EFFECT SNOW
SHOWERS/FLURRIES THIS MORNING WILL HINGE ON MID LEVEL CLOUDINESS
BEGINNING TO SPREAD IN ACTUALLY SEEDING THE LAKE STRATOCUMULUS.
LOW LEVEL FLOW WILL GRADUALLY BACK TO NORTH THIS AFTERNOON THEN
NORTH-NORTHWEST WITH THE RESULTANT LAKE EFFECT POTENTIAL PIVOTING
AROUND THE SOUTH RIM OF LAKE MICHIGAN THROUGH TONIGHT.
THERMODYNAMICS COULD IMPROVE SLIGHTLY THIS AFTERNOON...THOUGH
GETTING INTO A DIURNALLY UNFAVORABLE TIME OF DAY CONSIDERING THE
STILL MARGINAL SET UP FOR LAKE EFFECT SNOW TO GET CRANKING THIS
AFTERNOON. PLAN TO JUST GRADUALLY SHIFT FLURRIES/SMALL SNOW SHOWERS
CHANCES EAST FOCUSING MORE INTO NW INDY AND EXTREME SE COOK THIS
AFTERNOON.
MORE FAVORABLE THERMODYNAMIC ENVIRONMENT WILL DEVELOP THIS EVENING
AND CONTINUE OVERNIGHT WITH IMPROVED INSTABILITY AND SLIGHTLY HIGHER
INVERSION HEIGHTS. WILL MAINTAIN HIGH CHANCE/LOW END LIKELY POPS
NEAR THE LAKE TONIGHT BUT ACCUMULATIONS WILL PROBABLY BE PRETTY
MINOR BECAUSE AS THERMAL INSTABILITY INCREASES...MODELS ALSO PROG
INCREASINGLY DRY AIR TO SPREAD IN JUST ABOVE THE BOUNDARY LAYER
INVERSION WHICH GIVEN THE MARGINAL TEMPS IN THE CLOUD BARING LAYER
REALLY DOES NOT BODE WELL FOR EFFICIENTLY ACCUMULATING SNOW. CURRENT
THINKING IS NO ACCUMULATION IN NE IL AND MOSTLY LESS THAN AN INCH IN
NW INDY TONIGHT...THOUGH ISOLATED AMOUNTS OF 1 TO POSSIBLY UP TO 2
INCHES WOULD BE ON THE HIGH SIDE. LAKE EFFECT THREAT WILL SHIFT EAST
OUT OF THE CWA TUESDAY AND SHOULD SEE CLOUDS CLEAR OUT AND SKIES
BECOME SUNNY...BUT THE SUNSHINE WILL BE MORE FOR SHOW THAN ANYTHING
ELSE AS TEMPS STRUGGLE TO REACH 20F.
IZZI
&&
.LONG TERM...
220 AM CST
TUESDAY NIGHT THROUGH SUNDAY...
COLD AIR MASS WILL REMAIN ENTRENCHED WEDNESDAY BUT MAGNITUDE OF THE
COLD WILL NO DOUBT BE TEMPERED BY THE LACK OF SNOW COVER HERE OR
EVEN FAR UPSTREAM...SO WHILE IT WILL BE COLD HAVE GONE WITH TEMPS A
BIT ABOVE WHAT 850MB/925MB CLIMO WOULD SUPPORT. WARM ADVECTION
BEGINS WEDNESDAY NIGHT AND REALLY CRANKS INTO GEAR THURSDAY ALLOWING
FOR A NICE REBOUND IN TEMPS...THOUGH THE WARMING WILL BE MORE
ACADEMIC THAN ACTUALLY FELT AS GUSTY SOUTHWEST WINDS PRODUCE STILL
CHILLY WIND CHILLS THURSDAY. TEMPS SHOULD CONTINUE TO MODERATE ON
FRIDAY WITH PRECIPITATION LOOKING PRETTY UNLIKELY FRIDAY.
STRONG TROUGH WILL TO DIG INTO THE DESERT SOUTHWEST NEW YEARS EVE
AND IS FORECAST TO PRODUCE ACCUMULATING SNOW ON THE LAS VEGAS STRIP
NEW YEARS EVE WHERE WINTER STORM WATCHES ARE IN EFFECT! THIS
POWERFUL SYSTEM IS PROGGED TO CLOSE OFF A LARGE DEEP CIRCULATION
THAT BECOMES CUT OFF FROM THE WESTERLIES. A SET UP LIKE THIS MORE
OFTEN THAN NOT SPELLS BIG TROUBLES FOR PREDICTABILITY IN THE MEDIUM
RANGE AS THIS SYSTEM WILL PRESENT A COUPLE OF THE THINGS THAT MODELS
STRUGGLE WITH...FIRST HANDLING TRACK/TIMING OF EJECTING SOUTHWEST
CUT OFFS AND SECOND THE POTENTIAL FOR PHASING WITH NORTHERN STREAM
SHORTWAVE ENERGY.
THE RANGE OF POSSIBILITIES FOR THE WEEKEND IN OUR AREA TRULY RUN THE
GAMUT FROM DRY CONDITIONS ALL WEEKEND TO RAIN...ACCUMULATING
SNOW...A WINTRY MIX...OR SOME COMBINATION OF THE ABOVE. THE
OPERATIONAL GFS IS MOST GUNG-HO WITH PHASING AND FASTEST EJECTING
THE LOW EASTWARD...WHICH WOULD SEEM TO COUNTER WHAT IS TYPICAL IN
THESE SCENARIOS. THE PARALLEL GFS AND ECMWF ARE BOTH SOUTH AND
SLOWER WITH THE SYSTEM AND WOULD LEAD TO A DRY WEEKEND IN OUR AREA.
THE BLENDED MODEL POPS FOR THE WEEKEND HAVE COME DOWN FROM PREVIOUS
CYCLES AND AM NOT PLANNING ANY CHANGES TO THEM AS PREDICTABILITY IS
JUST TOO LOW AT THIS POINT. AT THIS POINT THE CHANCES OF THE LAS
VEGAS STRIP SEEING MORE ACCUMULATING SNOW THE NEXT 7 DAYS IS
CURRENTLY HIGHER THAN HERE IN OUR CWA...QUITE ATYPICAL AND
DEFINITELY NOT SOMETHING THAT ONE WOULD TYPICALLY WAGER WOULD BE
THE CASE!
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 12Z...
* SOME MVFR/LOW END VFR CIGS DEVELOPING AFTER DAYBREAK...AND
CONTINUING AT TIMES MONDAY.
* LAKE EFFECT FLURRIES THIS MORNING...AND POSSIBLY AGAIN BRIEFLY
THIS EVENING.
* NORTH/NORTHEAST WINDS APPROACHING 10KT THIS AFTERNOON.
KMD
//DISCUSSION...UPDATED 12Z...
LOW CLOUDS OVER SE WI ARE GONE...AND NOW WAITING FOR THE LAKE
STRATOCUMULUS. DIFFICULT TO SEE WHERE THE LOW CLOUDS ARE GIVEN THE
MID AND HIGHER CLOUD COMING IN ABOVE IT..BUT MVFR OR VERY LOW VFR
HAS LARGELY FILLED IN ON THE EAST SIDE OF LAKE MICHIGAN BASED ON
SURFACE OBS..AND KUGN IS SEEING THE LOW CLOUDS TOO...BUT VERY
LITTLE DOWNTOWN BASED ON SPOTTER REPORTS EARLY THIS MORNING. WINDS HAVE
TURNED NORTHERLY AND ARE EXPECTED TO TURN NORTHEASTERLY THIS
MORNING. THIS SHOULD ALLOW HIGH END MVFR OR LOW END VFR CIGS TO
ROLL IN CLOSER TO THE LAKE...THOUGH WITH LOW CONFIDENCE OF HOW FAR
INLAND THEY WILL GO. ALSO NOT SEEING MUCH IN THE WAY OF
FLURRIES/SNOW SHOWERS...THOUGH RAP/HRRR STILL ATTEMPT TO BRING A
FEW OVER THE NEAR LAKE AREAS. MODELS SUGGEST THAT ANY MVFR TO FORM
MAY NOT REMAIN FILLED IN. A SECONDARY SURGE OF LAKE CLOUDS COULD
VERY WELL SLIDE EAST OF ALL BUT GYY. WINDS TODAY WILL LIKELY
REMAIN NE AROUND 10 KT...POSSIBLY SOONER THAN IN THE CURRENT TAF.
WINDS THEN BACK TO NW IN THE EVENING.
KMD
//ORD AND MDW CONFIDENCE...UPDATED 12Z...
* MEDIUM-HIGH FOR MVFR CIGS...MEDIUM FOR TIMING AND HOW LONG THEY LAST.
* LOW-MEDIUM FOR LAKE EFFECT FLURRIES MONDAY/MONDAY EVENING.
* MEDIUM FOR WINDS THRU THE PERIOD.
KMD
//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...
* TUESDAY NIGHT...DRY/VFR. NORTHWEST WINDS.
* WEDNESDAY AND THURSDAY...DRY/VFR. GUSTY SOUTHWESTERLY WINDS.
* FRIDAY...DRY/VFR. SOUTH TO WEST WINDS.
* SATURDAY...CHANCE OF RAIN OR SNOW. IFR POSSIBLE.
* SUNDAY...CHANCE OF SNOW. IFR POSSIBLE.
KMD
&&
.MARINE...
247 AM CST
A COLD FRONT WILL CLEAR THE SOUTH END OF THE LAKE LATER THIS MORNING
AS STRONG HIGH PRESSURE IN NORTHWEST CANADA BEGINS TO BUILD SOUTH
INTO THE CENTRAL PLAINS. AS THE HIGH CONTINUES TO SLIDE INTO THE
PLAINS...LOW PRESSURE WILL TRACK SOUTHEAST THROUGH HUDSON BAY.
EXPECT A DECENT GRADIENT TO SETUP BETWEEN THESE TWO STRONG FEATURES.
THIS WILL CREATE A PERIOD OF GALES OVER THE LAKE WEDNESDAY AND
WEDNESDAY EVENING. THE HIGH WILL THEN SHIFT INTO THE TENNESSEE
VALLEY AND WEAKEN WHILE THE HUDSON BAY LOW RETREATS INTO THE
CANADIAN MARTIMES ON FRIDAY.
KMD
&&
.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:
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Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
308 AM CST Mon Dec 29 2014
.SHORT TERM...(Today)
ISSUED AT 308 AM CST MON DEC 29 2014
08z/2am surface analysis shows strong 1057mb high over northern
British Columbia/Alberta. Bitterly cold airmass beneath the high
with current temps in the teens and 20s below zero is building
southward into the Northern Plains/Upper Midwest, with the leading
edge of the colder air sinking toward northern Illinois. Front will
remain north of the KILX CWA today: however, increasing mid/high
clouds in the vicinity of the boundary will be noted across the
north. End result will be partly to mostly cloudy skies north of
Peoria, with mostly sunny skies further south across the remainder
of the area. High temperatures will once again be near normal for
this time of year in the middle to upper 30s.
&&
.LONG TERM...(Tonight through Sunday)
ISSUED AT 308 AM CST MON DEC 29 2014
Main weather story this week will be the shot of very cold air
expected Tuesday through Thursday. Arctic cold front will settle
southward into central Illinois tonight, accompanied by clouds and
perhaps a few flurries. NAM time-height cross-sections show much
shallower moisture profiles and weaker lift than they did on
previous runs: however, think strong CAA will still be enough to
produce scattered flurries overnight. Any flurries will come to
an end Tuesday morning as high pressure builds into the region and
skies gradually clear. High temperatures will be much colder than
today, ranging from the lower 20s northwest to the lower 30s south
of I-70. Heart of the coldest airmass will arrive Tuesday night
into Wednesday. Thanks to clear skies and diminishing winds, low
temperatures Tuesday night will bottom out in the single digits
and teens, with corresponding wind-chill readings dropping below
zero. Despite full sunshine, highs on Wednesday will struggle to
reach the lower to middle 20s. As high pressure sinks south of
the region, winds will back to the southwest and help boost temps
back into the lower 30s by Thursday.
Forecast becomes more complicated later in the week, as a southern
stream system slowly approaches from the southwest. Model-to-model
as well as run-to-run consistency remains poor, so forecast
confidence beyond Thursday is low. Latest trend observed with the
00z Dec 29 model suite suggests a deeper cut-off low over the Desert
Southwest and thus a slower northeastward ejection. Current water
vapor imagery shows a strong jet streak diving southward along the
West Coast, which is progged to carve out a closed upper low over
California within the next 48 hours. Models are in very good
agreement initially, showing the low meandering slowly eastward to
the Texas/Oklahoma panhandles by Saturday evening: however, they
have very different ideas on how to handle precip ahead of the
system. The ECMWF shows precip breaking out well in advance of
the low across the southern Plains Thursday, then spreading
northeastward into south-central Illinois and the Ohio River
Valley late Thursday night into Friday. Given presence of
cold/dry airmass across the region, am very skeptical about this
aggressive push of precip. As a result, will continue with a dry
forecast Thursday night and will reduce PoPs significantly during
the day Friday. The GFS seems to have a much more realistic
solution, showing precip remaining south of Illinois until Friday
night into Saturday. Models are in poor agreement with what
happens to the southwest system over the weekend, with the ECMWF
maintaining a closed 500mb low longer than the GFS, which opens
the wave and allows it to be absorbed into the northern stream
much faster. If the ECMWF verifies, much of the precip associated
with the low will remain southeast of Illinois across the Ohio
River Valley. This is a drastic change from its previous runs, so
am looking at this with a great deal of skepticism. Prefer the
more consistent GFS, which opens the low and brings it northward
into the area on Saturday. As a result, have introduced chance
PoPs across the board Friday night/Saturday, then have ended
precip chances by Sunday as the system exits into the Great Lakes.
Precip type will be an issue as well, with forecast soundings and
surface temps initially supporting snow or a rain/snow mix.
Atmosphere will likely warm enough to change the precip to mostly
rain on Saturday before colder air returns Saturday night into
Sunday. Overall this does not look like a major winter storm for
central Illinois, but future model runs will need to be monitored
for any potential changes.
&&
.AVIATION...(For the 06Z TAFS through 06Z Monday night)
ISSUED AT 1146 PM CST SUN DEC 28 2014
High pressure centered across our counties will keep VFR
conditions in general. Some fog is indicated in the HRRR and RAP
models along the ridge axis for CMI and DEC. The RAP goes all the
way to VLIFR with the fog across CMI/DEC/SPI, while the HRRR keeps
the LIFR fog east of CMI. Will add MVFR fog at CMI and DEC as
light fog is developing along that axis already near-by.
A weak cold front extending from SE Nebraska to southern Michigan
will slowly drift to the southeast over the next day. As the cold
front approaches Monday evening, MVFR clouds are expected to
arrive from NW to SE.
The increasing clouds will be triggered by a shortwave moving
east along the front as it arrives in the area. A few flurries
could develop for the northern terminals of PIA and BMI. Models
have trended drier with the last 2 runs, so do not expect any snow
accumulation as the NAM was suggesting previously. Will add -sn at
PIA and BMI Monday evening, and keep the other TAF sites dry.
Winds will remain calm under the surface ridge axis tonight. A
northeast wind will develop by mid-morning on Monday and continue
through the rest of the TAF period. Wind speeds will remain less
than 10kt.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Barnes
LONG TERM...Barnes
AVIATION...Shimon
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1152 PM CST SUN DEC 28 2014
.SHORT TERM...
346 PM CST
REMAINDER OF THIS AFTERNOON AND TONIGHT...
QUIET WEATHER WILL CONTINUE THROUGH THE REMAINDER OF THIS AFTERNOON
AND TONIGHT WITH CLEAR SKIES OVER MUCH OF THE CWA. THE ONLY CLOUD
COVER OF SIGNIFICANT IS A LAYER OF DENSE CIRRUS OVER NWRN INDIANA
AND EAST-CENTRAL IL ASSOCIATED WITH THE SUBTROPICAL JET STREAM
EXTENDING FROM THE WRN GLFMEX THROUGH NEW ENGLAND. AS SFC HIGH
PRESSURE CONTINUES TO SPREAD SOUTHEAST TOWARD THE OHIO VALLEY...ALL
CLOUD COVER SHOULD MOVE OUT OF THE AREA AND CLEAR SKIES SHOULD
PREVAIL ACROSS THE REGION TONIGHT. THE AMPLE SUNSHINE HAS SLIGHTLY
COUNTERED THE PERSISTENT COLD ADVECTION ACROSS THE REGION...ALLOWING
TEMPERATURES TO TOP OUT IN THE LOWER 30S THIS AFTERNOON. WHILE
WINDS ARE EXPECTED TO DROP OFF OVERNIGHT WITH THE BUILDING HIGH
PRESSURE...DIRECTION SHOULD VEER A BIT MORE NELY...SETTING UP A
FETCH OFF OF LAKE MICHIGAN...SO SFC DEWPOINTS SHOULD REMAIN IN THE
UPPER TEENS TO LOWER 20S...WITH THE VERY DRY AIR CURRENTLY OVER THE
UPPER MISSISSIPPI VALLEY WITH SFC DEWPOINTS IN THE SINGLE DIGITS
ABOVE 0F TO THE SINGLE DIGITS BELOW 0F REMAINING TO THE NORTH AND
WEST OF THE CWA...LIMITING THE RADIATIVE COOLING. SO...ONLY EXPECT
THAT TEMPS SHOULD DROP INTO THE LOWER TO MIDDLE 20S ACROSS THE
AREA...WITH UPPER 20S TEMPS NEAR THE LAKE.
KREIN
&&
.LONG TERM...
346 PM CST
MONDAY THROUGH SUNDAY...
THE NEXT WEATHER OF CONCERN WILL BE THE CHANCES FOR LAKE EFFECT SNOW
ACROSS NERN IL AND NWRN IN. AS THE SFC HIGH BUILDS ACROSS THE
REGION...LOW LEVEL WINDS WILL INITIALLY BE NELY MONDAY MORNING.
MODEL SOUNDINGS INDICATE AT LEAST SOME WEAK INSTABILITY OVER THE SRN
END OF THE LAKE...WHICH WOULD BE CONDUCIVE TO LAKE EFFECT SNOW
SPREADING INLAND BEGINNING EARLY MONDAY MORNING. LOW LEVEL FLOW
WILL GRADUALLY BACK FROM NELY...THROUGH NLY MONDAY NIGHT AND THEN
NWLY BY TUESDAY MORNING. EQUILIBRIUM HEIGHTS THROUGH THE PERIOD
WILL RANGE FROM ARND 4KFT-6KT WITH LAKE INDUCED CAPE OF ARND
300-400J/KG...SO SOME LAKE EFFECT SNOW WILL BE LIKELY...BUT
ANTICIPATE THAT THE GREATEST CHANCES FOR ACCUMULATING SNOW WILL BE
RELATIVELY CLOSE TO THE LAKE...WITH ONLY SCT -SHSN OR FLURRIES
FARTHER INLAND INTO THE CHICAGO METRO AREA. ALSO...WITH LOW LEVEL
FLOW SLOWLY...BUT CONTINUOUSLY BACKING FROM NELY TO NWLY FROM MONDAY
MORNING THROUGH TUESDAY MORNING...DO NOT ANTICIPATE THAT ANY SINGLE
LAKE PLUME...SHOULD ONE DEVELOP...TO REMAIN OVER ANY GIVEN AREA FOR
A SIGNIFICANT AMOUNT OF TIME...SO WOULD ANTICIPATE THAT ANY
ACCUMULATIONS WOULD BE BELOW ADVISORY CRITERIA. LATEST INDICATORS
SUGGEST THAT THE COOK COUNTY LAKEFRONT...INCLUDING DOWNTOWN CHICAGO
COULD SEE 1 TO 3 INCHES TOTAL SNOWFALL...WHILE NWRN INDIANA MAY SEE
2 TO 4 INCHES. HOWEVER...THESE AMOUNTS WILL BE HIGHLY DEPENDENT ON
SFC FETCH AND HOW QUICKLY SFC WINDS WILL BACK FROM NELY TO NWLY...SO
THERE IS STILL SOME UNCERTAINTY IN THE SNOWFALL AMOUNTS. HAVE
BETTER CONFIDENCE IN GENERAL THAT ACCUMULATING SNOW WILL BE CONFINED
TO LOCATIONS NEAR THE LAKE AND THAT ANY SNOW OBSERVED FARTHER INLAND
WILL BE CLOSER TO A DUSTING. BY TUESDAY AFTERNOON...LOW LEVEL WINDS
SHOULD VEER FAR ENOUGH THAT ANY LAKE EFFECT SNOW SHOULD BE OUT OF
THE CWA...WITH THE POSSIBLE EXCEPTION OF FAR NERN PORTER COUNTY.
TEMPERATURES FOR MONDAY SHOULD RANGE FROM THE UPPER 20S TO AROUND 30
ALONG THE WISCONSIN BORDER TO THE MIDDLE 30S SOUTH OF I-80. THE
MORE SIGNIFICANT COOLING TREND WILL BEGIN MONDAY NIGHT AS THE ARCTIC
HIGH PRESSURE SPREADS ACROSS THE AREA AND INTO THE OHIO VALLEY AND
THROUGH THE LOWER MISSISSIPPI VALLEY. BY TUESDAY
MORNING...ANTICIPATE LOW TO RANGE FROM THE LOWER TEENS OVER THE
ROCKFORD AREA TO THE LOWER 20S EAST OF THE I-55 CORRIDOR.
PERSISTENT COLD ADVECTION WILL KEEP HIGHS ON TUESDAY AND WEDNESDAY
IN THE MIDDLE TO UPPER TEENS. THE LOWEST TEMPS SHOULD OCCUR
WEDNESDAY MORNING WITH MUCH OF THE CWA SEEING TEMPS DROP INTO THE
SINGLE DIGITS ABOVE 0F OVER NRN IL AND 10-13F OVER NWRN INDIANA.
WITH WINDS REMAINING AROUND 10 MPH THROUGH THE NIGHT...MIN WIND
CHILL READINGS TUESDAY MORNING SHOULD DROP TO AROUND -5F TO -10F.
SOME MODERATION IS EXPECTED FOR LATER IN THE WEEK...BUT TEMPERATURES
SHOULD REMAIN AROUND SEASONAL NORMAL LEVELS. THE NEXT QUESTION FOR
THE EXTENDED FORECAST PERIOD WILL FOCUS ON THE EVOLUTION OF A STRONG
PACIFIC SHORTWAVE DROPPING DOWN THE WEST COAST AND CLOSING OFF OVER
THE DESERT SOUTHWEST WEDNESDAY NIGHT AND THURSDAY. THE DIGGING
TROUGH OVER THE WEST SHOULD INITIATE SOME HEIGHT RISES OVER THE
MIDWEST...WHICH WILL HELP WITH THE MODERATING TEMPERATURES IN SPITE
OF PERSISTENT NWLY FLOW ALOFT AS BROAD LOW AMPLITUDE TROUGHING
DEVELOPS OVER THE NCNTRL/NERN CONUS WHILE AN UPPER HIGH PARKS OVER
THE GREATER ANTILLES AND WRN CARIBBEAN. THE FORECAST CONCERNS WILL
FOCUS ON HOW QUICKLY THE UPPER LOW WILL LIFT OUT OF THE DESERT
SOUTHWEST WITH SRN STREAM ENERGY LIFTING THROUGH THE SRN PLAINS
AND...ULTIMATELY INTO THE SRN GREAT LAKES...AND HOW MUCH PHASING
WILL OCCUR WITH NRN STREAM ENERGY. THE 12Z GFS IS STILL TRENDING
MUCH QUICKER THAN THE OTHER LONGER RANGE GUIDANCE WITH THE 12Z ECMWF
ADVERTISING THE SLOWEST SOLUTION AND THE GEM TAKING A MIDDLE OF THE
ROAD SOLUTION. STILL FAVOR A SLOWER SOLUTION FOR A SRN STREAM
CUT-OFF AS THE MODELS ARE NOTORIOUS FOR BEING TOO FAST IN LIFTING
THESE SYSTEM NEWD. THE GENERAL TREND FOR THE LATTER PORTIONS OF THE
EXTENDED FORECAST PERIOD SHOULD BE FOR INCREASING TEMPERATURES AND
POPS BY THE END OF THE WEEK AND INTO THE WEEKEND...BUT CONFIDENCE IS
STILL LOW ON THE EXACT DETAILS OF ANY ASSOCIATED PCPN. TEMPERATURES
THROUGH THEN PERIOD SHOULD GENERALLY BE LOW ENOUGH TO SUPPORT SOME
SNOW...BUT THERE COULD ALSO BE PERIODS WHERE TEMPS COULD BE HIGH
ENOUGH FOR SOME OF THE PCPN TO BE EITHER RAIN OR A RAIN-SNOW MIX.
KREIN
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* MVFR CIGS DEVELOPING OVERNIGHT...AND CONTINUING AT TIMES MONDAY.
* LAKE EFFECT FLURRIES MONDAY AND MONDAY EVENING.
* NORTH/NORTHEAST WINDS APPROACHING 10KT MONDAY AFTERNOON.
KMD
//DISCUSSION...UPDATED 06Z...
MVFR CIGS OVER SOUTHERN WI WILL MOVE SOUTH DURING THE EARLY
MORNING HOURS LIKELY SPREADING INTO NORTHERN ILLNOIS IN THE COMING
HOURS. MEANWHILE...ADDITIONAL LOW CLOUDS OVER THE LAKE WILL
SPREAD INTO NE ILLINOIS TOWARD DAYBREAK WITH MVFR CIGS CONTINUING
MONDAY. LOW- MEDIUM CONFIDENCE REGARDING HOW SOON THESE CIGS WILL
ARRIVE BUT ONCE THEY DO...EXPECT THEM TO LINGER THROUGH THE
MORNING...AND THROUGH THE AFTERNOON CLOSE TO THE LAKEFRONT. NE
WINDS LOOK TO GET AROUND 10 KT THIS AFTERNOON WITH THESE LOWER
CIGS IN PLACE.
AS COLDER AIRSPREADS ACROSS THE AREA...LAKE EFFECT FLURRIES OR
SNOW SHOWERS ARE POSSIBLE MONDAY INTO MONDAY NIGHT. HRRR/RAP
SUGGEST A PERIOD OF FLURRIES OR LIGHT SNOW SHOWERS THIS MORNING
AFTER 13Z AS THE LEADING EDGE OF COLDER AIR SPREADS SOUTH...POSSIBLY
LASTING OFF AN ON FOR SEVERAL HOURS. NO ACCUMULATIONS ARE EXPECTED
UNLESS A SHOWER COMES RIGHT OVER A TERMINAL. ALLL OF THIS IS EAST
OF RFD/DPA. MAINTAINED A PROB30 FOR SHOWER ACTIVITY AND WILL
MONITOR AS THINGS MATERIALIZE OR NOT LATER THIS MORNING. THEN
THERE APPEARS TO BE A LULL IN ANYTHING MORE THAN LAKE CLOUDS. BEST
CHANCES FOR LAKE EFFECT SNOW SHOWERS AT GYY COULD BE MONDAY
EVENING.
KMD
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* HIGH FOR MVFR CIGS...MEDIUM FOR TIMING.
* MEDIUM FOR LAKE EFFECT FLURRIES MONDAY/MONDAY EVENING.
* MEDIUM FOR WINDS THRU THE PERIOD.
KMD
//OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z...
* TUESDAY...DRY. MVFR CIGS POSSIBLE. NORTHWEST WINDS.
* WEDNESDAY AND THURSDAY...DRY/VFR. GUSTY WESTERLY WINDS.
* FRIDAY...CHANCE OF SNOW. MVFR POSSIBLE. SOUTH/SOUTHEAST WINDS.
* SATURDAY...CHANCE OF RAIN OR SNOW. IFR POSSIBLE. SOUTH WINDS
BECOMING WEST.
&&
.MARINE...
326 PM CST
LIGHTER SPEEDS HAVE BEEN OBSERVED OVER THE LAKE TODAY...WHILE A
NORTHWEST DIRECTION PREVAILED. A LINGERING TROUGH OF LOW PRESSURE
OVER SOUTHEAST ONTARIO IS HELPING FOR SLIGHTLY HIGHER SPEEDS OVER
THE NORTHERN HALF OF THE LAKE WHERE 15 TO 25 KT WINDS CONTINUE TO
BE OBSERVED...WITH 10 TO 20 KT BEING OBSERVED OVER THE SOUTHERN
HALF. THIS WILL LIKELY CONTINUE TONIGHT AS A FRONT PUSHES SOUTH
DOWN THE LAKE...AND THEN AS HIGH PRESSURE BUILDS SOUTHEAST THROUGH
THE UPPER MIDWEST AND GREAT LAKES. THIS HIGH WILL THEN CONTINUE TO
BUILD SOUTHEAST ON MONDAY...WITH THE CENTER OF THE STRONG HIGH
BUILDING SOUTH ACROSS THE PLAINS TUESDAY INTO WEDNESDAY. THIS WILL
HELP WITH A NORTH TO NORTHWEST WIND TO REMAIN IN PLACE DURING THIS
PERIOD...BEFORE WINDS TURN MORE WESTERLY TUESDAY NIGHT INTO
WEDNESDAY. EXPECT WINDS TO SIGNIFICANTLY INCREASE DURING THE DAY
WEDNESDAY WITH GALES APPEARING TO BE LIKELY...AS THE STRONG HIGH
REMAINS TO THE SOUTHWEST AND DEVELOPING LOW PRESSURE MOVES SOUTH
THROUGH HUDSON BAY.
RODRIGUEZ
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1146 PM CST Sun Dec 28 2014
.UPDATE...
ISSUED AT 900 PM CST SUN DEC 28 2014
Clear skies early this evening allowed temps to drop off quickly
toward overnight lows. Some cirrus streaming into the NW half of
our forecast area will help to slow down the temp falls the rest
of the night. Still expect a few more degrees of temp drop under
those clouds, and another 3-5 deg where skies remain clear. Temps
are approaching the dewpoints already, which will also work to
slow additional temp falls. However, still decided to trim a few
degrees from lows in most areas, with higher changes toward
Danville.
Winds will remain light and variable under the surface ridge axis,
extending across Illinois from northeast Oklahoma to northwest
Indiana. The remainder of the forecast looks on track with no
weather makers until possibly Monday night when flurries develop
with the next shortwave. Updated info will be available shortly.
&&
.SHORT TERM...(Tonight)
ISSUED AT 310 PM CST SUN DEC 28 2014
High pressure briefly building into the region this evening as
clouds slowly erode and move off to the southeast. Colder air
moving in with clearing skies tonight will drop overnight lows a few
more degrees from last nights lows. With the ridge axis moving into
the region, the winds become light and variable in the overnight,
allowing for more efficient radiational cooling in addition to the
colder airmass. Other than the cold start to the morning, weather
tonight rather quiet for the Midwest.
&&
.LONG TERM...(Monday through Sunday)
ISSUED AT 310 PM CST SUN DEC 28 2014
As the high pressure shifts to the southeast, a larger, colder high
pressure area will slide in with Arctic air. There will be a thin
boundary between the two air masses and with this, there will be a
small chance of flurries as it passes. Timing of this feature looks
to be Monday night and Tuesday morning. This colder Arctic high will
bring well below normal temps to the region for Tue night through
Wed night. The coldest lows are expected to be Tue night and the
coldest highs on Wed. Breezy northwest winds during the period will
also create wind chills below zero across the northern part of the
state, especially Tue night and Wed morning.
This high pressure will dominate the weather through Thur night and
will slide into the eastern US by Thur evening. With this high to
the east and an upper level low in the southwest US, moisture and
warmer temps will begin to advect back northward into the region.
Model differ on the timing of this return flow and this results in
differences in timing of the return of pcpn to the area. The ECMWF
is quicker and further east with the track of a low pressure area,
along with the associated pcpn. The GFS is slower and further west
to northwest with the track, and thereby brings more warm air into
the region ahead of the low pressure area, and more pcpn. Looks like
the regional blend leans toward the GFS with a western track, more
warm air ahead of the system and more of a spread of pcpn over the
area. The next question then, is what will p-type be during the
period. Due to the spread of the models, confidence is low, so will
keep p-type simple and just go with snow becoming rain or snow, and
then just rain, and then back to rain or snow. 850mb temps look to
be couple of degrees above freezing, so would expect rain well north
into the cwa. However, the question is the sfc temps. Anywhere with
temps below freezing has the potential of receiving freezing rain.
But if the rain is heavy enough, then temps could remain at or just
above freezing overnight Friday. To repeat, forecast confidence is
low due to model spread, so will not be adding any freezing pcpn at
this time. As the system gets closer and the models reach some
agreement and consistency, forecast changes are likely. Beyond this
system, dry and cooler temps are again expected for Sat night and
Sunday.
&&
.AVIATION...(For the 06Z TAFS through 06Z Monday night)
ISSUED AT 1146 PM CST SUN DEC 28 2014
High pressure centered across our counties will keep VFR
conditions in general. Some fog is indicated in the HRRR and RAP
models along the ridge axis for CMI and DEC. The RAP goes all the
way to VLIFR with the fog across CMI/DEC/SPI, while the HRRR keeps
the LIFR fog east of CMI. Will add MVFR fog at CMI and DEC as
light fog is developing along that axis already near-by.
A weak cold front extending from SE Nebraska to southern Michigan
will slowly drift to the southeast over the next day. As the cold
front approaches Monday evening, MVFR clouds are expected to
arrive from NW to SE.
The increasing clouds will be triggered by a shortwave moving
east along the front as it arrives in the area. A few flurries
could develop for the northern terminals of PIA and BMI. Models
have trended drier with the last 2 runs, so do not expect any snow
accumulation as the NAM was suggesting previously. Will add -sn at
PIA and BMI Monday evening, and keep the other TAF sites dry.
Winds will remain calm under the surface ridge axis tonight. A
northeast wind will develop by mid-morning on Monday and continue
through the rest of the TAF period. Wind speeds will remain less
than 10kt.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Shimon
SHORT TERM...HJS
LONG TERM...Auten
AVIATION...Shimon
AREA FORECAST DISCUSSION
NWS JACKSON KY
131 PM EST MON DEC 29 2014
.UPDATE...
ISSUED AT 130 PM EST MON DEC 29 2014
CLOUD COVER HOLDING OVER THE AREA THIS AFTERNOON HAS REALLY IMPACTED
TEMPERATURES. STILL HAD TO LOWER MAX TEMPS A FEW DEGREES ACROSS THE
AREA. WILL CONTINUE TO KEEP CLOUD COVER OVER THE AREA INTO TONIGHT
BUT WILL BRING SOME CLEARING INTO THE NORTHWEST. THIS IN
MIND...PRECIP HAS WANED A BIT IN THE EAST AND SHORT TERM MODELS HINT
AT RAIN TONIGHT BEING MORE CONFINED TO THE EAST DUE TO THE LOW
FINALLY BEGINNING TO PUSH EAST. HOWEVER...SOME LINGERING RAIN ALONG
THE HIGHER TERRAIN WILL BEGIN TO MIX WITH AND CHANGE TO ALL SNOW LATE
TONIGHT. THOUGH ACCUMULATION IS NOT EXPECTED. OTHERWISE...THE MAIN
CHANGE TO THIS UPDATE WAS TO TAKE PATCHY FOG OUT OF THE FORECAST. A
NEW ZFP HAS BEEN ISSUED WITH THIS UPDATE.
UPDATE ISSUED AT 1041 AM EST MON DEC 29 2014
A MOIST LOWER PORTION OF THE ATMOSPHERE COUPLED WITH A SLOWLY EXITING
LOW PRESSURE SYSTEM ON THE LEE SIDE OF THE APPALACHIANS HAS AND WILL
RESULT IN LINGERING CLOUD COVER OVER EASTERN KENTUCKY. IN FACT...WEAK
N TO NNE FLOW INTO THE AREA IS BARELY ERODING ANY CLOUD COVER OVER IN
CENTRAL OH AND IN. WILL EXPECT CLOUD COVER TO LINGER THROUGH TODAY
AND INTO TONIGHT...AT LEAST INTO EASTERN KENTUCKY. THE NORTHERN AND
WESTERN BLUEGRASS AREAS WILL EVENTUALLY BEGIN TO CLEAR OUT
TONIGHT...EVEN INTO FLEMING...BATH AND ROWAN COUNTIES. WITH THIS IN
MIND...HAVE UPDATED THE FORECAST TO LOWER MAX TEMPS FOR TODAY AS
CLOUD COVER WILL KEEP ANY HEATING FROM REACHING THE
SURFACE...ESPECIALLY IN A NORTHERLY FLOW. SOME LINGERING DRIZZLE AND
LIGHT RAIN STILL REMAIN IN THE EAST THIS MORNING AND MAY LINGER INTO
THE AFTERNOON BANKED AGAINST THE HIGHER TERRAIN IN THE EAST. STILL
ONLY A SLIGHT CHANCE IS WORTH MENTIONING. THE FOG WAS LEFT IN THE
FORECAST AS SOME OBSERVATIONS WERE STILL SHOWING SOME GROUND TRUTH OF
THIS. THE FOG MAY LINGER THROUGHOUT THE ENTIRE DAY WITH THE MOIST
BOUNDARY LAYER AND DRIZZLE PRESENT. WILL VISIT THIS AGAIN AROUND THE
NOON TIME PERIOD. A NEW ZFP HAS BEEN SENT OUT TO ADDRESS THESE
CHANGES.
UPDATE ISSUED AT 640 AM EST MON DEC 29 2014
WSR-88D RADAR CONTINUES TO INDICATE SOME LIGHT RAIN AND DRIZZLE THIS
MORNING WITH BEST RETURNS ACROSS THE FAR SE PORTIONS OF THE CWA. ALSO
WITH LOW LEVEL MOISTURE IN PLACE THERE WILL BE PATCHY FOG IN SPOTS
WITH MANY METAR SITES COMING IN WITH ANYWHERE FROM HALF A MILE TO TWO
AND A HALF MILE VIS THIS MORNING. SO DID UPDATE WITH SOME DRIZZLE AND
PATCHY FOG. ALSO FRESHENED UP TEMPS/DEWPOINTS/WIND WITH LATEST OBS
AND TRENDS. NO MAJOR CHANGES NEEDED THIS UPDATE.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 347 AM EST MON DEC 29 2014
THIS MORNING WSR-88D RADAR CONTINUES TO INDICATE AN AREA OF RAIN AND
DRIZZLE TRACKING ACROSS PORTIONS OF THE SOUTHERN AND EASTERN PARTS OF
THE CWA. THE HRRR HAS NOT BE HANDLING THIS THE BEST AND WAS TOO
SLOW...BUT THE 00Z RUN OF THE NAM DID HAVE A HINT OF THE ACTIVITY
MOVING ACROSS. THEREFORE LEANED TOWARD IT FOR A PORTION OF THE
PERIOD. THIS HAS BEEN AIDED BY SHORTWAVE ENERGY AND LOW PRESSURE
ALONG AND NEAR THE FRONTAL BOUNDARY TO THE EAST. THIS ACTIVITY WILL
SLOWLY MOVE EAST THROUGH THE DAY TODAY WITH SLIGHT CHANCES OF PRECIP
PERSISTING ACROSS THE FAR SOUTHEAST. SOME OF THE ACTIVITY ACROSS THE
FAR SOUTHEAST COULD SWITCH OVER TO SOME LIGHT SNOW OR RAIN/SNOW MIX
TONIGHT BEFORE ACTIVITY SLOWLY DIES OFF AS COLD AIR MOVES INTO THE
REGION. GIVEN MINIMAL MOISTURE WOULD NOT EXPECT ANY ACCUMULATIONS
WITH THIS CHANGE OVER. MUCH OF THE REGION IS EXPECTED TO STAY MOSTLY
CLOUDY TODAY INTO TONIGHT...HOWEVER PORTIONS OF THE FAR NW COULD SEE
SOME PARTLY CLOUDY SKIES BUILDING IN LATE TONIGHT AS HIGH PRESSURE
SLOWLY BUILDS EAST. MOVING INTO TUESDAY HIGH PRESSURE WILL CONTINUE
TO BUILD EAST INTO THE REGION WITH MODEL SOUNDINGS FINALLY INDICATING
SOME DRIER AIR FILTERING INTO THE REGION. THIS WILL GIVE WAY TO
PARTLY TO MOSTLY SUNNY SKIES BUT NEAR TO BELOW NORMAL TEMPERATURES
FOR THE DAY ON TUESDAY WITH HIGHS IN THE LOWER 40S SOUTH AND MID TO
UPPER 30S NORTH.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 347 AM EST MON DEC 29 2014
MODELS APPEAR TO BE IN DECENT AGREEMENT UNTIL THE LAST 24 TO 48
HOURS OF THE EXTENDED. BOTH THE NORTHERN AND SOUTHERN STREAMS ARE
ACTIVE THROUGH THE PERIOD AS SHORTWAVES SPEED EASTWARD THROUGH BROAD
CYCLONIC FLOW ACROSS THE NORTHERN TIER AND A CUT OFF LOW THAT
GENERALLY TRACKS FROM CA/NV THROUGH THE DESERT SOUTHWEST AND ACROSS
THE SOUTHERN CONUS. THIS LOW THEN MERGES WITH THE NORTHERN STREAM AS
IT PASSES THROUGH THE EASTERN CONUS TOWARDS THE END OF THE EXTENDED.
MAIN DIFFERENCES BETWEEN THE ECMWF AND GFS OCCUR WITH THE TIMING AT
WHICH THE CUTOFF LOW MERGES BACK INTO THE NORTHERN STREAM. THE MORE
CONSISTENT GFS IS PROGRESSIVE AND FURTHER NORTH WITH THE TRACK OF
THE LOW WHILE THE ECMWF IS SLOWER AND FURTHER SOUTH WITH THIS
FEATURE. AN APPARENT REVERSAL FROM PREVIOUS CYCLES. DIFFICULT
DECISION WHETHER TO RELY ON THE MORE CONSISTENT GFS OR THE TYPICALLY
BETTER PERFORMING ECMWF WHICH ALSO HAS A HISTORY FOR BEING BETTER AT
PICKING UP ON NEW TRENDS. FOR NOW WILL STICK WITH A TRUE BLEND...OR
MODEL CONSENSUS FOR THE FORECAST.
A VERY WEAK UPPER LEVEL SHORTWAVE TROUGH WILL PROVIDE A GLANCING
BLOW TO OUR FORECAST AREA EARLY IN THE PERIOD...WEDNESDAY. THIS
FEATURE WILL NOT PRODUCE ANY SENSIBLE WEATHER BUT WILL SEND A
REINFORCING SHOT OF COLDER AIR INTO OHIO VALLEY. THAT LEAVES AS OUR
MAIN WEATHER MAKER FOR THE EXTENDED THE AFOREMENTIONED CUTOFF LOW.
AS IS ALMOST ALWAYS THE CASE FOR THESE TYPES OF SITUATIONS...THE
EXACT TRACK AND TIMING OF THE LOW ACROSS THE EASTERN CONUS WILL BE
THE DETERMINING FACTOR IN OUR SENSIBLE WEATHER. THE ECMWF HAS
TRENDED FURTHER SOUTH...WITH A COLDER SOLUTION AND A BETTER
POTENTIAL FOR SOME TYPE OF WINTRY WEATHER FOR PORTIONS OF THE OHIO
VALLEY. THE GFS IS WARMER AND WETTER WITH ITS SOLUTION.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 130 PM EST MON DEC 29 2014
MOSTLY ALL THE DRIZZLE AND LIGHT RAIN IS COMING TO AN END ACROSS
EASTERN KENTUCKY WITH THEN EXCEPTION OF THE FAR EAST. THE EXTENSIVE
CLOUD COVER IS THOUGH...EXPECTED TO LINGER INTO TONIGHT. THE EDGE OF
THE LOWER CLOUD COVER IS EXPECTED TO LIFT FROM NORTHWEST TO SOUTHEAST
THROUGH TONIGHT AND INTO TOMORROW. SO WILL EXPECT TAF LOCATIONS SUCH
AS SYM TO IMPROVE FIRST...THEN FOLLOWED BY SME...LOZ...JKL...AND SJS
AS THE HIGHER CEILINGS MOVE IN FROM THE WEST AND NORTHWEST. BY
TOMORROW...HIGH PRESSURE SHOULD TAKE CONTROL OVER MUCH OF THE AREA
WITH VFR CONDITIONS EXPECTED BY THE END OF THE TAF PERIOD. WINDS WILL
BE LIGHT THROUGH THE PERIOD.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...SHALLENBERGER
SHORT TERM...DJ
LONG TERM...RAY
AVIATION...SHALLENBERGER
AREA FORECAST DISCUSSION
NWS JACKSON KY
1041 AM EST MON DEC 29 2014
.UPDATE...
ISSUED AT 1041 AM EST MON DEC 29 2014
A MOIST LOWER PORTION OF THE ATMOSPHERE COUPLED WITH A SLOWLY EXITING
LOW PRESSURE SYSTEM ON THE LEE SIDE OF THE APPALACHIANS HAS AND WILL
RESULT IN LINGERING CLOUD COVER OVER EASTERN KENTUCKY. IN FACT...WEAK
N TO NNE FLOW INTO THE AREA IS BARELY ERODING ANY CLOUD COVER OVER IN
CENTRAL OH AND IN. WILL EXPECT CLOUD COVER TO LINGER THROUGH TODAY
AND INTO TONIGHT...AT LEAST INTO EASTERN KENTUCKY. THE NORTHERN AND
WESTERN BLUEGRASS AREAS WILL EVENTUALLY BEGIN TO CLEAR OUT
TONIGHT...EVEN INTO FLEMING...BATH AND ROWAN COUNTIES. WITH THIS IN
MIND...HAVE UPDATED THE FORECAST TO LOWER MAX TEMPS FOR TODAY AS
CLOUD COVER WILL KEEP ANY HEATING FROM REACHING THE
SURFACE...ESPECIALLY IN A NORTHERLY FLOW. SOME LINGERING DRIZZLE AND
LIGHT RAIN STILL REMAIN IN THE EAST THIS MORNING AND MAY LINGER INTO
THE AFTERNOON BANKED AGAINST THE HIGHER TERRAIN IN THE EAST. STILL
ONLY A SLIGHT CHANCE IS WORTH MENTIONING. THE FOG WAS LEFT IN THE
FORECAST AS SOME OBSERVATIONS WERE STILL SHOWING SOME GROUND TRUTH OF
THIS. THE FOG MAY LINGER THROUGHOUT THE ENTIRE DAY WITH THE MOIST
BOUNDARY LAYER AND DRIZZLE PRESENT. WILL VISIT THIS AGAIN AROUND THE
NOON TIME PERIOD. A NEW ZFP HAS BEEN SENT OUT TO ADDRESS THESE
CHANGES.
UPDATE ISSUED AT 640 AM EST MON DEC 29 2014
WSR-88D RADAR CONTINUES TO INDICATE SOME LIGHT RAIN AND DRIZZLE THIS
MORNING WITH BEST RETURNS ACROSS THE FAR SE PORTIONS OF THE CWA. ALSO
WITH LOW LEVEL MOISTURE IN PLACE THERE WILL BE PATCHY FOG IN SPOTS
WITH MANY METAR SITES COMING IN WITH ANYWHERE FROM HALF A MILE TO TWO
AND A HALF MILE VIS THIS MORNING. SO DID UPDATE WITH SOME DRIZZLE AND
PATCHY FOG. ALSO FRESHENED UP TEMPS/DEWPOINTS/WIND WITH LATEST OBS
AND TRENDS. NO MAJOR CHANGES NEEDED THIS UPDATE.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 347 AM EST MON DEC 29 2014
THIS MORNING WSR-88D RADAR CONTINUES TO INDICATE AN AREA OF RAIN AND
DRIZZLE TRACKING ACROSS PORTIONS OF THE SOUTHERN AND EASTERN PARTS OF
THE CWA. THE HRRR HAS NOT BE HANDLING THIS THE BEST AND WAS TOO
SLOW...BUT THE 00Z RUN OF THE NAM DID HAVE A HINT OF THE ACTIVITY
MOVING ACROSS. THEREFORE LEANED TOWARD IT FOR A PORTION OF THE
PERIOD. THIS HAS BEEN AIDED BY SHORTWAVE ENERGY AND LOW PRESSURE
ALONG AND NEAR THE FRONTAL BOUNDARY TO THE EAST. THIS ACTIVITY WILL
SLOWLY MOVE EAST THROUGH THE DAY TODAY WITH SLIGHT CHANCES OF PRECIP
PERSISTING ACROSS THE FAR SOUTHEAST. SOME OF THE ACTIVITY ACROSS THE
FAR SOUTHEAST COULD SWITCH OVER TO SOME LIGHT SNOW OR RAIN/SNOW MIX
TONIGHT BEFORE ACTIVITY SLOWLY DIES OFF AS COLD AIR MOVES INTO THE
REGION. GIVEN MINIMAL MOISTURE WOULD NOT EXPECT ANY ACCUMULATIONS
WITH THIS CHANGE OVER. MUCH OF THE REGION IS EXPECTED TO STAY MOSTLY
CLOUDY TODAY INTO TONIGHT...HOWEVER PORTIONS OF THE FAR NW COULD SEE
SOME PARTLY CLOUDY SKIES BUILDING IN LATE TONIGHT AS HIGH PRESSURE
SLOWLY BUILDS EAST. MOVING INTO TUESDAY HIGH PRESSURE WILL CONTINUE
TO BUILD EAST INTO THE REGION WITH MODEL SOUNDINGS FINALLY INDICATING
SOME DRIER AIR FILTERING INTO THE REGION. THIS WILL GIVE WAY TO
PARTLY TO MOSTLY SUNNY SKIES BUT NEAR TO BELOW NORMAL TEMPERATURES
FOR THE DAY ON TUESDAY WITH HIGHS IN THE LOWER 40S SOUTH AND MID TO
UPPER 30S NORTH.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 347 AM EST MON DEC 29 2014
MODELS APPEAR TO BE IN DECENT AGREEMENT UNTIL THE LAST 24 TO 48
HOURS OF THE EXTENDED. BOTH THE NORTHERN AND SOUTHERN STREAMS ARE
ACTIVE THROUGH THE PERIOD AS SHORTWAVES SPEED EASTWARD THROUGH BROAD
CYCLONIC FLOW ACROSS THE NORTHERN TIER AND A CUT OFF LOW THAT
GENERALLY TRACKS FROM CA/NV THROUGH THE DESERT SOUTHWEST AND ACROSS
THE SOUTHERN CONUS. THIS LOW THEN MERGES WITH THE NORTHERN STREAM AS
IT PASSES THROUGH THE EASTERN CONUS TOWARDS THE END OF THE EXTENDED.
MAIN DIFFERENCES BETWEEN THE ECMWF AND GFS OCCUR WITH THE TIMING AT
WHICH THE CUTOFF LOW MERGES BACK INTO THE NORTHERN STREAM. THE MORE
CONSISTENT GFS IS PROGRESSIVE AND FURTHER NORTH WITH THE TRACK OF
THE LOW WHILE THE ECMWF IS SLOWER AND FURTHER SOUTH WITH THIS
FEATURE. AN APPARENT REVERSAL FROM PREVIOUS CYCLES. DIFFICULT
DECISION WHETHER TO RELY ON THE MORE CONSISTENT GFS OR THE TYPICALLY
BETTER PERFORMING ECMWF WHICH ALSO HAS A HISTORY FOR BEING BETTER AT
PICKING UP ON NEW TRENDS. FOR NOW WILL STICK WITH A TRUE BLEND...OR
MODEL CONSENSUS FOR THE FORECAST.
A VERY WEAK UPPER LEVEL SHORTWAVE TROUGH WILL PROVIDE A GLANCING
BLOW TO OUR FORECAST AREA EARLY IN THE PERIOD...WEDNESDAY. THIS
FEATURE WILL NOT PRODUCE ANY SENSIBLE WEATHER BUT WILL SEND A
REINFORCING SHOT OF COLDER AIR INTO OHIO VALLEY. THAT LEAVES AS OUR
MAIN WEATHER MAKER FOR THE EXTENDED THE AFOREMENTIONED CUTOFF LOW.
AS IS ALMOST ALWAYS THE CASE FOR THESE TYPES OF SITUATIONS...THE
EXACT TRACK AND TIMING OF THE LOW ACROSS THE EASTERN CONUS WILL BE
THE DETERMINING FACTOR IN OUR SENSIBLE WEATHER. THE ECMWF HAS
TRENDED FURTHER SOUTH...WITH A COLDER SOLUTION AND A BETTER
POTENTIAL FOR SOME TYPE OF WINTRY WEATHER FOR PORTIONS OF THE OHIO
VALLEY. THE GFS IS WARMER AND WETTER WITH ITS SOLUTION.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 647 AM EST MON DEC 29 2014
DRIZZLE AND LIGHT RAIN HAS BEEN THE TREND OVERNIGHT. TAF SITES HAVE BEEN
FLUCTUATING OVERNIGHT SOME WITH MOST SITES STAYING IFR TO LIFR CONDITIONS.
SOME DRIER AIR HAS BEEN ABLE TO TO MAKE IT INTO NW PORTIONS OF THE
CWA WITH SYM CIGS MVFR...HOWEVER FOG IS EXPECTED TO STILL BE A ISSUE
AT MOST SITES AND COULD BRING LOWER CONDITIONS TO THESE SITES THAT
SEE THE HIGHER CIGS. MOVING INTO TODAY WOULD EXPECT SOME
IMPROVEMENTS TO THE TAF SITES AS FOG LIFTS SLOWLY...BUT MOST SITES
ARE ONLY EXPECTED TO IMPROVE TO MVFR CONDITIONS AS WE MOVE INTO THIS
AFTERNOON.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...SHALLENBERGER
SHORT TERM...DJ
LONG TERM...RAY
AVIATION...DJ
AREA FORECAST DISCUSSION
NWS JACKSON KY
648 AM EST MON DEC 29 2014
.UPDATE...
ISSUED AT 640 AM EST MON DEC 29 2014
WSR-88D RADAR CONTINUES TO INDICATE SOME LIGHT RAIN AND DRIZZLE THIS
MORNING WITH BEST RETURNS ACROSS THE FAR SE PORTIONS OF THE CWA. ALSO
WITH LOW LEVEL MOISTURE IN PLACE THERE WILL BE PATCHY FOG IN SPOTS
WITH MANY METAR SITES COMING IN WITH ANYWHERE FROM HALF A MILE TO TWO
AND A HALF MILE VIS THIS MORNING. SO DID UPDATE WITH SOME DRIZZLE AND
PATCHY FOG. ALSO FRESHENED UP TEMPS/DEWPOINTS/WIND WITH LATEST OBS
AND TRENDS. NO MAJOR CHANGES NEEDED THIS UPDATE.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 347 AM EST MON DEC 29 2014
THIS MORNING WSR-88D RADAR CONTINUES TO INDICATE AN AREA OF RAIN AND
DRIZZLE TRACKING ACROSS PORTIONS OF THE SOUTHERN AND EASTERN PARTS OF
THE CWA. THE HRRR HAS NOT BE HANDLING THIS THE BEST AND WAS TOO
SLOW...BUT THE 00Z RUN OF THE NAM DID HAVE A HINT OF THE ACTIVITY
MOVING ACROSS. THEREFORE LEANED TOWARD IT FOR A PORTION OF THE
PERIOD. THIS HAS BEEN AIDED BY SHORTWAVE ENERGY AND LOW PRESSURE
ALONG AND NEAR THE FRONTAL BOUNDARY TO THE EAST. THIS ACTIVITY WILL
SLOWLY MOVE EAST THROUGH THE DAY TODAY WITH SLIGHT CHANCES OF PRECIP
PERSISTING ACROSS THE FAR SOUTHEAST. SOME OF THE ACTIVITY ACROSS THE
FAR SOUTHEAST COULD SWITCH OVER TO SOME LIGHT SNOW OR RAIN/SNOW MIX
TONIGHT BEFORE ACTIVITY SLOWLY DIES OFF AS COLD AIR MOVES INTO THE
REGION. GIVEN MINIMAL MOISTURE WOULD NOT EXPECT ANY ACCUMULATIONS
WITH THIS CHANGE OVER. MUCH OF THE REGION IS EXPECTED TO STAY MOSTLY
CLOUDY TODAY INTO TONIGHT...HOWEVER PORTIONS OF THE FAR NW COULD SEE
SOME PARTLY CLOUDY SKIES BUILDING IN LATE TONIGHT AS HIGH PRESSURE
SLOWLY BUILDS EAST. MOVING INTO TUESDAY HIGH PRESSURE WILL CONTINUE
TO BUILD EAST INTO THE REGION WITH MODEL SOUNDINGS FINALLY INDICATING
SOME DRIER AIR FILTERING INTO THE REGION. THIS WILL GIVE WAY TO
PARTLY TO MOSTLY SUNNY SKIES BUT NEAR TO BELOW NORMAL TEMPERATURES
FOR THE DAY ON TUESDAY WITH HIGHS IN THE LOWER 40S SOUTH AND MID TO
UPPER 30S NORTH.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 347 AM EST MON DEC 29 2014
MODELS APPEAR TO BE IN DECENT AGREEMENT UNTIL THE LAST 24 TO 48
HOURS OF THE EXTENDED. BOTH THE NORTHERN AND SOUTHERN STREAMS ARE
ACTIVE THROUGH THE PERIOD AS SHORTWAVES SPEED EASTWARD THROUGH BROAD
CYCLONIC FLOW ACROSS THE NORTHERN TIER AND A CUT OFF LOW THAT
GENERALLY TRACKS FROM CA/NV THROUGH THE DESERT SOUTHWEST AND ACROSS
THE SOUTHERN CONUS. THIS LOW THEN MERGES WITH THE NORTHERN STREAM AS
IT PASSES THROUGH THE EASTERN CONUS TOWARDS THE END OF THE EXTENDED.
MAIN DIFFERENCES BETWEEN THE ECMWF AND GFS OCCUR WITH THE TIMING AT
WHICH THE CUTOFF LOW MERGES BACK INTO THE NORTHERN STREAM. THE MORE
CONSISTENT GFS IS PROGRESSIVE AND FURTHER NORTH WITH THE TRACK OF
THE LOW WHILE THE ECMWF IS SLOWER AND FURTHER SOUTH WITH THIS
FEATURE. AN APPARENT REVERSAL FROM PREVIOUS CYCLES. DIFFICULT
DECISION WHETHER TO RELY ON THE MORE CONSISTENT GFS OR THE TYPICALLY
BETTER PERFORMING ECMWF WHICH ALSO HAS A HISTORY FOR BEING BETTER AT
PICKING UP ON NEW TRENDS. FOR NOW WILL STICK WITH A TRUE BLEND...OR
MODEL CONSENSUS FOR THE FORECAST.
A VERY WEAK UPPER LEVEL SHORTWAVE TROUGH WILL PROVIDE A GLANCING
BLOW TO OUR FORECAST AREA EARLY IN THE PERIOD...WEDNESDAY. THIS
FEATURE WILL NOT PRODUCE ANY SENSIBLE WEATHER BUT WILL SEND A
REINFORCING SHOT OF COLDER AIR INTO OHIO VALLEY. THAT LEAVES AS OUR
MAIN WEATHER MAKER FOR THE EXTENDED THE AFOREMENTIONED CUTOFF LOW.
AS IS ALMOST ALWAYS THE CASE FOR THESE TYPES OF SITUATIONS...THE
EXACT TRACK AND TIMING OF THE LOW ACROSS THE EASTERN CONUS WILL BE
THE DETERMINING FACTOR IN OUR SENSIBLE WEATHER. THE ECMWF HAS
TRENDED FURTHER SOUTH...WITH A COLDER SOLUTION AND A BETTER
POTENTIAL FOR SOME TYPE OF WINTRY WEATHER FOR PORTIONS OF THE OHIO
VALLEY. THE GFS IS WARMER AND WETTER WITH ITS SOLUTION.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 647 AM EST MON DEC 29 2014
DRIZZLE AND LIGHT RAIN HAS BEEN THE TREND OVERNIGHT. TAF SITES HAVE BEEN
FLUCTUATING OVERNIGHT SOME WITH MOST SITES STAYING IFR TO LIFR CONDITIONS.
SOME DRIER AIR HAS BEEN ABLE TO TO MAKE IT INTO NW PORTIONS OF THE
CWA WITH SYM CIGS MVFR...HOWEVER FOG IS EXPECTED TO STILL BE A ISSUE
AT MOST SITES AND COULD BRING LOWER CONDITIONS TO THESE SITES THAT
SEE THE HIGHER CIGS. MOVING INTO TODAY WOULD EXPECT SOME
IMPROVEMENTS TO THE TAF SITES AS FOG LIFTS SLOWLY...BUT MOST SITES
ARE ONLY EXPECTED TO IMPROVE TO MVFR CONDITIONS AS WE MOVE INTO THIS
AFTERNOON.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...DJ
SHORT TERM...DJ
LONG TERM...RAY
AVIATION...DJ
AREA FORECAST DISCUSSION
NWS JACKSON KY
348 AM EST MON DEC 29 2014
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 347 AM EST MON DEC 29 2014
THIS MORNING WSR-88D RADAR CONTINUES TO INDICATE AN AREA OF RAIN AND
DRIZZLE TRACKING ACROSS PORTIONS OF THE SOUTHERN AND EASTERN PARTS OF
THE CWA. THE HRRR HAS NOT BE HANDLING THIS THE BEST AND WAS TOO
SLOW...BUT THE 00Z RUN OF THE NAM DID HAVE A HINT OF THE ACTIVITY
MOVING ACROSS. THEREFORE LEANED TOWARD IT FOR A PORTION OF THE
PERIOD. THIS HAS BEEN AIDED BY SHORTWAVE ENERGY AND LOW PRESSURE
ALONG AND NEAR THE FRONTAL BOUNDARY TO THE EAST. THIS ACTIVITY WILL
SLOWLY MOVE EAST THROUGH THE DAY TODAY WITH SLIGHT CHANCES OF PRECIP
PERSISTING ACROSS THE FAR SOUTHEAST. SOME OF THE ACTIVITY ACROSS THE
FAR SOUTHEAST COULD SWITCH OVER TO SOME LIGHT SNOW OR RAIN/SNOW MIX
TONIGHT BEFORE ACTIVITY SLOWLY DIES OFF AS COLD AIR MOVES INTO THE
REGION. GIVEN MINIMAL MOISTURE WOULD NOT EXPECT ANY ACCUMULATIONS
WITH THIS CHANGE OVER. MUCH OF THE REGION IS EXPECTED TO STAY MOSTLY
CLOUDY TODAY INTO TONIGHT...HOWEVER PORTIONS OF THE FAR NW COULD SEE
SOME PARTLY CLOUDY SKIES BUILDING IN LATE TONIGHT AS HIGH PRESSURE
SLOWLY BUILDS EAST. MOVING INTO TUESDAY HIGH PRESSURE WILL CONTINUE
TO BUILD EAST INTO THE REGION WITH MODEL SOUNDINGS FINALLY INDICATING
SOME DRIER AIR FILTERING INTO THE REGION. THIS WILL GIVE WAY TO
PARTLY TO MOSTLY SUNNY SKIES BUT NEAR TO BELOW NORMAL TEMPERATURES
FOR THE DAY ON TUESDAY WITH HIGHS IN THE LOWER 40S SOUTH AND MID TO
UPPER 30S NORTH.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 347 AM EST MON DEC 29 2014
MODELS APPEAR TO BE IN DECENT AGREEMENT UNTIL THE LAST 24 TO 48
HOURS OF THE EXTENDED. BOTH THE NORTHERN AND SOUTHERN STREAMS ARE
ACTIVE THROUGH THE PERIOD AS SHORTWAVES SPEED EASTWARD THROUGH BROAD
CYCLONIC FLOW ACROSS THE NORTHERN TIER AND A CUT OFF LOW THAT
GENERALLY TRACKS FROM CA/NV THROUGH THE DESERT SOUTHWEST AND ACROSS
THE SOUTHERN CONUS. THIS LOW THEN MERGES WITH THE NORTHERN STREAM AS
IT PASSES THROUGH THE EASTERN CONUS TOWARDS THE END OF THE EXTENDED.
MAIN DIFFERENCES BETWEEN THE ECMWF AND GFS OCCUR WITH THE TIMING AT
WHICH THE CUTOFF LOW MERGES BACK INTO THE NORTHERN STREAM. THE MORE
CONSISTENT GFS IS PROGRESSIVE AND FURTHER NORTH WITH THE TRACK OF
THE LOW WHILE THE ECMWF IS SLOWER AND FURTHER SOUTH WITH THIS
FEATURE. AN APPARENT REVERSAL FROM PREVIOUS CYCLES. DIFFICULT
DECISION WHETHER TO RELY ON THE MORE CONSISTENT GFS OR THE TYPICALLY
BETTER PERFORMING ECMWF WHICH ALSO HAS A HISTORY FOR BEING BETTER AT
PICKING UP ON NEW TRENDS. FOR NOW WILL STICK WITH A TRUE BLEND...OR
MODEL CONSENSUS FOR THE FORECAST.
A VERY WEAK UPPER LEVEL SHORTWAVE TROUGH WILL PROVIDE A GLANCING
BLOW TO OUR FORECAST AREA EARLY IN THE PERIOD...WEDNESDAY. THIS
FEATURE WILL NOT PRODUCE ANY SENSIBLE WEATHER BUT WILL SEND A
REINFORCING SHOT OF COLDER AIR INTO OHIO VALLEY. THAT LEAVES AS OUR
MAIN WEATHER MAKER FOR THE EXTENDED THE AFOREMENTIONED CUTOFF LOW.
AS IS ALMOST ALWAYS THE CASE FOR THESE TYPES OF SITUATIONS...THE
EXACT TRACK AND TIMING OF THE LOW ACROSS THE EASTERN CONUS WILL BE
THE DETERMINING FACTOR IN OUR SENSIBLE WEATHER. THE ECMWF HAS
TRENDED FURTHER SOUTH...WITH A COLDER SOLUTION AND A BETTER
POTENTIAL FOR SOME TYPE OF WINTRY WEATHER FOR PORTIONS OF THE OHIO
VALLEY. THE GFS IS WARMER AND WETTER WITH ITS SOLUTION.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 100 AM EST MON DEC 29 2014
FRONTAL BOUNDARY HAS MOVED SOUTH OF THE REGION TONIGHT WITH SURFACE
LOW RIDING UP ACROSS THE CAROLINA/TENNESSEE BORDER INDICATED BY 03Z
SURFACE ANALYSIS. MOST OF THE HEAVIER RAIN SHOWER ACTIVITY HAS MOVED
SOUTH OF THE REGION TONIGHT...HOWEVER DRIZZLE OR ISOLATED SHOWERS
WILL BE POSSIBLE OVERNIGHT. TAF SITES HAVE BEEN FLUCTUATING TONIGHT
WITH MOST SITES SEEING IFR TO LIFR CONDITIONS. SOME DRIER AIR HAS
BEEN ABLE TO TO MAKE IT INTO NW PORTIONS OF THE CWA WITH SYM CIGS
MVFR...HOWEVER FOG IS EXPECTED TO STILL BE A ISSUE AT MOST SITES AND
COULD BRING LOWER CONDITIONS TO THESE SITES THAT SEE THE HIGHER CIGS.
MOVING INTO TOMORROW MORNING WOULD EXPECT SOME IMPROVEMENTS TO THE
TAF SITES AS FOG LIFTS SLOWLY...BUT MOST SITES ARE ONLY EXPECTED TO
IMPROVE TO MVFR CONDITIONS AS WE MOVE INTO TOMORROW.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...DJ
LONG TERM...RAY
AVIATION...DJ
AREA FORECAST DISCUSSION
NWS JACKSON KY
218 AM EST MON DEC 29 2014
.UPDATE...
ISSUED AT 218 AM EST MON DEC 29 2014
THIS EVENING WE ARE SEEING A AREA OF RAIN AND DRIZZLE MOVING NE
ACROSS THE SW PORTIONS OF THE CWA TONIGHT. DID UP POPS A BIT TO
ENCOMPASS THE BETTER RADAR RETURNS AND OBSERVATIONS. MOST OF THE THIS
WILL BE LIGHT WITH GENERALLY A TENTH OF A INCH OR LESS. DID FRESHEN
UP TEMPS/DEWPOINTS/WINDS WITH LATEST OBS AND TRENDS.
UPDATE ISSUED AT 1100 PM EST SUN DEC 28 2014
RAIN IS TAPERING OFF SLIGHTLY FASTER THAN WAS NOTED IN THE PREVIOUS
UPDATE. TRIMMED BACK POPS AND HAVE THEM MOVING SE AT A FASTER RATE
NOW TO BETTER COORDINATE WITH THE CURRENT RADAR TRENDS. EVEN
STILL...WON/T BE SURPRISED IF THE POPS END UP MOVING OUT EVEN FASTER
THAN THE CURRENT FORECAST. THE CURRENT HRRR MODEL WOULD SUGGEST
CONTINUED SE MOVEMENT OF THE RAIN MOVING OUT OF MUCH OF THE CWA
BY 7Z...BUT BECOMING STALLED OUT ACROSS THE HIGHER TERRAIN FROM 7Z
THROUGH TOMORROW MORNING. THE MODEL HAS INITIALIZED WELL...BUT THIS
WILL BE SOMETHING TO WATCH.
UPDATE ISSUED AT 647 PM EST SUN DEC 28 2014
TWO MAIN CHANGES TO THE FORECAST. FIRST WAS TO CHANGE THE POPS OVER
THE NEXT FEW HOURS TO CENTER THE HIGHEST AMOUNTS OVER THE MORE
CENTRAL PORTION OF THE CWA...SLOWLY SHIFTING MORE EASTWARD INTO THE
HIGHEST TERRAIN OVER THE NEXT SEVERAL HOURS...THEN LINGERING SLIGHTLY
LONGER ACROSS THE SW CWA THAN WAS PREVIOUSLY FORECAST. THIS BETTER
ACCOUNTED FOR ONGOING CONDITIONS...AS WELL AS WHAT BOTH THE HI RES
AND SHORT TERM MODELS WERE FORECASTING. THE SECOND CHANGE WAS TO ADD
FOG WORDING TO THE CWA THROUGH THE OVERNIGHT HOURS. MUCH OF KY IS
REPORTING FOG...IN AREAS WITH AND WITHOUT RAIN. EXPECT THIS FOG TO
CONTINUE AS WE HEAD INTO THE OVERNIGHT HOURS WITH LOW LEVEL MOISTURE
FROM RAIN EXPECTED TO CONTINUE. THIS FOG SHOULD THEN BURN OFF DURING
THE MORNING HOURS AS DRIER AIR MOVES IN AND RAIN MOVES OUT. VALLEYS
WILL BE THE LAST TO CLEAR OUT. UPDATED THE NEAR TERM GRIDS WITH THE
LATEST OBSERVATIONAL DATA FOR TEMPS...DEW POINTS...AND WINDS TO MAKE
SURE THE CURRENT CONDITIONS WERE REFLECTED IN THE FORECAST.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 359 PM EST SUN DEC 28 2014
CURRENT CONDITIONS ACROSS THE AREA FEATURES RAIN CONTINUING TO MOVE
INTO THE AREA FROM THE SOUTHWEST. THE COLD FRONT HAS NOW PUSHED EAST
OF EASTERN KENTUCKY WITH NORTHWESTERLY FLOW NOW INTO THE AREA.
FREEZING TEMPERATURES LOOK TO BE NORTH AND WEST OF THE FORECAST AREA
AND SNOW IS NOT EXPECTED AT THIS TIME AS THE COLDER AIR IS A BIT TO
SLOW TO ADVECT INTO THE AREA BEFORE THE BULK OF THE MOISTURE EXITS TO THE
EAST TONIGHT. MEANWHILE...SURFACE LOW PRESSURE HAS DEVELOPED AND WILL
MOVE NORTHEAST THROUGH EASTERN TN TONIGHT. THIS WILL KEEP PRECIP
THROUGH FAR EASTERN KENTUCKY THROUGH THE NIGHT AS ANOTHER SURGE OF
MOISTURE WILL MOVE NORTHEAST. WITH THE MOIST LOW LEVELS...THOUGH
THERE WILL BE SOME CLOUD COVER...DO EXPECT SOME PATCHY FOG DEVELOPING
TONIGHT AND HAS ALREADY BEEN THE CASE IN SOME OF THE BLUEGRASS AREAS.
ESPECIALLY PLACES THAT REMAIN SATURATED THROUGH THE NIGHT.
CLOUD COVER AND PRECIP WILL SLOWLY MOVE OFF TO THE EAST FOR MONDAY
WITH SOME RAIN FALL SKIRTING ALONG THE FAR EASTERN COUNTIES AS THE
LOW EXITS OF TO THE EAST. HEADING INTO MONDAY NIGHT...THE COLDER AIR
WILL FILTER INTO THE AREA AND SOME LINGERING RAIN IN THE EAST MAY
CHANGE OR MIX TO SNOW IN THE HIGHER ELEVATIONS TOWARDS TUESDAY
MORNING. PARTIAL CLEARING IN THE NORTHWESTERN COUNTIES WILL RESULT IN
TEMPERATURES DROPPING INTO THE MID 20S FOR LOWS.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 359 PM EST SUN DEC 28 2014
THE EXTENDED PORTION OF THE FORECAST WILL BE BROKEN UP INTO THREE
SEGMENTS. PART ONE...ISOLATED RAIN AND SNOW SHOWERS ARE FORECAST TO
LINGER IN THE NORTHERLY MEAGERLY MOIST FLOW BEHIND A DEPARTING COLD
FRONT AND UPPER LEVEL LOW PRESSURE SYSTEM. THE SECOND PERIOD WILL
FEATURE AN EAST TO WEST ELONGATED RIDGE OF HIGH PRESSURE THAT IS
EXPECTED TO DROP SOUTHWARD OUT OF THE GREAT LAKES REGION TUESDAY
THROUGH THURSDAY. PART THREE WILL FEATURE A WELL DEVELOPED AND VERY
MOISTURE LADEN WEATHER SYSTEM THAT WILL AFFECT THE REGION FROM
THURSDAY NIGHT THROUGH SUNDAY. THE WEATHER SYSTEM THAT WILL BE
LEAVING THE AREA ON TUESDAY SHOULD BRING NOTHING MORE THAN LIGHT
RAIN AND SNOW WITH LITTLE OR NO SNOW ACCUMULATION. TEMPERATURES TO
BEGIN THE PERIOD LOOK TO BE BELOW NORMAL...WITH HIGHS IN THE 40S
DURING THE DAY...AND LOWS TUESDAY NIGHT IN THE LOW TO MID 20S. AN
ARCTIC AIR MASS IS THEN PROGGED TO SETTLE OVER THE REGION MID WEEK.
HIGHS ON WEDNESDAY AND THURSDAY WILL LIKELY NOT MAKE IT OUT OF THE
30S. OVERNIGHT LOWS WEDNESDAY AND THURSDAY NIGHT WILL BE EVEN
CHILLIER...WITH THE MERCURY BOTTOMING OUT AROUND 20 WEDNESDAY
NIGHT...AND THE MID TO UPPER 20S THURSDAY NIGHT.
THE BIG STORY IN THE EXTENDED WILL BE THE WEATHER SYSTEM THAT IS
FORECAST TO SOAK THE AREA TOWARD THE END OF THE WEEK. THERE IS NO
QUESTION THAT A POTENT WEATHER SYSTEM WITH EXTENSIVE PRECIPITATION
WILL AFFECT THE STATE OF KENTUCKY FRIDAY AND SATURDAY. THE QUESTIONS
WITH THIS SYSTEM WILL BE HOW QUICKLY WILL PRECIPITATION MOVE INTO
THE AREA AND HOW MUCH OF THE PRECIP WILL BE IN THE FORM OF SNOW?
RIGHT NOW THE GFS IS MUCH SLOWER AND WARMER THAN THE ECMWF WITH THE
END OF WEEK WEATHER PATTERN. THE GFS HAS ITS LOW MOVING FURTHER
NORTH THAN THE ECMWF. THAT BEING SAID...WITH SO MUCH UNCERTAINTY
INVOLVED...DECIDED TO GO WITH A COMPROMISE BETWEEN THE TWO
MODELS...SLIGHTLY FAVORING THE COLDER ECMWF MODEL. THIS IS BASED ON
THE FACT THAT THE MODELS HAVE BEEN RUNNING A BIT TOO WARM LATELY
WITH REGARDS TO LOW AND MIDDLE LEVEL TEMPERATURES. AFTER A PERIOD OF
MIXED PRECIP THURSDAY EVENING...AN AREA OF LIGHT SNOW IS BEING
FORECAST TO DEVELOP LATE THURSDAY NIGHT THROUGH EARLY FRIDAY
MORNING. THERE COULD BE SOME LIGHT ACCUMULATIONS WITH THIS BAND OF
SNOW AS IT MOVES NORTH...BUT IT WILL LIKELY NOT STAY ON THE GROUND
LONG AS TEMPERATURES RISE INTO THE 40S ON FRIDAY. AN EXTENDED PERIOD
OF GOOD SOAKING RAIN IS EXPECTED FRIDAY THROUGH SATURDAY...WITH THE
POTENTIAL FOR SOME SNOW ALONG AND NORTH OF I-64 FRIDAY NIGHT AND
SATURDAY NIGHT...AS SOME NEAR FREEZING AIR COULD SPILL INTO THAT
AREA EACH NIGHT. AS IS COMMON IN WINTER...THE MODELS WILL NEED TO BE
WATCHED VERY CLOSELY TO SEE WHICH DIRECTION THINGS TREND...MORE RAIN
OR MORE SNOW WILL BE THE QUESTION AS WE MOVE FORWARD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 100 AM EST MON DEC 29 2014
FRONTAL BOUNDARY HAS MOVED SOUTH OF THE REGION TONIGHT WITH SURFACE
LOW RIDING UP ACROSS THE CAROLINA/TENNESSEE BORDER INDICATED BY 03Z
SURFACE ANALYSIS. MOST OF THE HEAVIER RAIN SHOWER ACTIVITY HAS MOVED
SOUTH OF THE REGION TONIGHT...HOWEVER DRIZZLE OR ISOLATED SHOWERS
WILL BE POSSIBLE OVERNIGHT. TAF SITES HAVE BEEN FLUCTUATING TONIGHT
WITH MOST SITES SEEING IFR TO LIFR CONDITIONS. SOME DRIER AIR HAS
BEEN ABLE TO TO MAKE IT INTO NW PORTIONS OF THE CWA WITH SYM CIGS
MVFR...HOWEVER FOG IS EXPECTED TO STILL BE A ISSUE AT MOST SITES AND
COULD BRING LOWER CONDITIONS TO THESE SITES THAT SEE THE HIGHER CIGS.
MOVING INTO TOMORROW MORNING WOULD EXPECT SOME IMPROVEMENTS TO THE
TAF SITES AS FOG LIFTS SLOWLY...BUT MOST SITES ARE ONLY EXPECTED TO
IMPROVE TO MVFR CONDITIONS AS WE MOVE INTO TOMORROW.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...DJ
SHORT TERM...SHALLENBERGER
LONG TERM...AR
AVIATION...DJ
AREA FORECAST DISCUSSION
NWS JACKSON KY
102 AM EST MON DEC 29 2014
.UPDATE...
ISSUED AT 1100 PM EST SUN DEC 28 2014
RAIN IS TAPERING OFF SLIGHTLY FASTER THAN WAS NOTED IN THE PREVIOUS
UPDATE. TRIMMED BACK POPS AND HAVE THEM MOVING SE AT A FASTER RATE
NOW TO BETTER COORDINATE WITH THE CURRENT RADAR TRENDS. EVEN
STILL...WON/T BE SURPRISED IF THE POPS END UP MOVING OUT EVEN FASTER
THAN THE CURRENT FORECAST. THE CURRENT HRRR MODEL WOULD SUGGEST
CONTINUED SE MOVEMENT OF THE RAIN MOVING OUT OF MUCH OF THE CWA
BY 7Z...BUT BECOMING STALLED OUT ACROSS THE HIGHER TERRAIN FROM 7Z
THROUGH TOMORROW MORNING. THE MODEL HAS INITIALIZED WELL...BUT THIS
WILL BE SOMETHING TO WATCH.
UPDATE ISSUED AT 647 PM EST SUN DEC 28 2014
TWO MAIN CHANGES TO THE FORECAST. FIRST WAS TO CHANGE THE POPS OVER
THE NEXT FEW HOURS TO CENTER THE HIGHEST AMOUNTS OVER THE MORE
CENTRAL PORTION OF THE CWA...SLOWLY SHIFTING MORE EASTWARD INTO THE
HIGHEST TERRAIN OVER THE NEXT SEVERAL HOURS...THEN LINGERING SLIGHTLY
LONGER ACROSS THE SW CWA THAN WAS PREVIOUSLY FORECAST. THIS BETTER
ACCOUNTED FOR ONGOING CONDITIONS...AS WELL AS WHAT BOTH THE HI RES
AND SHORT TERM MODELS WERE FORECASTING. THE SECOND CHANGE WAS TO ADD
FOG WORDING TO THE CWA THROUGH THE OVERNIGHT HOURS. MUCH OF KY IS
REPORTING FOG...IN AREAS WITH AND WITHOUT RAIN. EXPECT THIS FOG TO
CONTINUE AS WE HEAD INTO THE OVERNIGHT HOURS WITH LOW LEVEL MOISTURE
FROM RAIN EXPECTED TO CONTINUE. THIS FOG SHOULD THEN BURN OFF DURING
THE MORNING HOURS AS DRIER AIR MOVES IN AND RAIN MOVES OUT. VALLEYS
WILL BE THE LAST TO CLEAR OUT. UPDATED THE NEAR TERM GRIDS WITH THE
LATEST OBSERVATIONAL DATA FOR TEMPS...DEW POINTS...AND WINDS TO MAKE
SURE THE CURRENT CONDITIONS WERE REFLECTED IN THE FORECAST.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 359 PM EST SUN DEC 28 2014
CURRENT CONDITIONS ACROSS THE AREA FEATURES RAIN CONTINUING TO MOVE
INTO THE AREA FROM THE SOUTHWEST. THE COLD FRONT HAS NOW PUSHED EAST
OF EASTERN KENTUCKY WITH NORTHWESTERLY FLOW NOW INTO THE AREA.
FREEZING TEMPERATURES LOOK TO BE NORTH AND WEST OF THE FORECAST AREA
AND SNOW IS NOT EXPECTED AT THIS TIME AS THE COLDER AIR IS A BIT TO
SLOW TO ADVECT INTO THE AREA BEFORE THE BULK OF THE MOISTURE EXITS TO THE
EAST TONIGHT. MEANWHILE...SURFACE LOW PRESSURE HAS DEVELOPED AND WILL
MOVE NORTHEAST THROUGH EASTERN TN TONIGHT. THIS WILL KEEP PRECIP
THROUGH FAR EASTERN KENTUCKY THROUGH THE NIGHT AS ANOTHER SURGE OF
MOISTURE WILL MOVE NORTHEAST. WITH THE MOIST LOW LEVELS...THOUGH
THERE WILL BE SOME CLOUD COVER...DO EXPECT SOME PATCHY FOG DEVELOPING
TONIGHT AND HAS ALREADY BEEN THE CASE IN SOME OF THE BLUEGRASS AREAS.
ESPECIALLY PLACES THAT REMAIN SATURATED THROUGH THE NIGHT.
CLOUD COVER AND PRECIP WILL SLOWLY MOVE OFF TO THE EAST FOR MONDAY
WITH SOME RAIN FALL SKIRTING ALONG THE FAR EASTERN COUNTIES AS THE
LOW EXITS OF TO THE EAST. HEADING INTO MONDAY NIGHT...THE COLDER AIR
WILL FILTER INTO THE AREA AND SOME LINGERING RAIN IN THE EAST MAY
CHANGE OR MIX TO SNOW IN THE HIGHER ELEVATIONS TOWARDS TUESDAY
MORNING. PARTIAL CLEARING IN THE NORTHWESTERN COUNTIES WILL RESULT IN
TEMPERATURES DROPPING INTO THE MID 20S FOR LOWS.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 359 PM EST SUN DEC 28 2014
THE EXTENDED PORTION OF THE FORECAST WILL BE BROKEN UP INTO THREE
SEGMENTS. PART ONE...ISOLATED RAIN AND SNOW SHOWERS ARE FORECAST TO
LINGER IN THE NORTHERLY MEAGERLY MOIST FLOW BEHIND A DEPARTING COLD
FRONT AND UPPER LEVEL LOW PRESSURE SYSTEM. THE SECOND PERIOD WILL
FEATURE AN EAST TO WEST ELONGATED RIDGE OF HIGH PRESSURE THAT IS
EXPECTED TO DROP SOUTHWARD OUT OF THE GREAT LAKES REGION TUESDAY
THROUGH THURSDAY. PART THREE WILL FEATURE A WELL DEVELOPED AND VERY
MOISTURE LADEN WEATHER SYSTEM THAT WILL AFFECT THE REGION FROM
THURSDAY NIGHT THROUGH SUNDAY. THE WEATHER SYSTEM THAT WILL BE
LEAVING THE AREA ON TUESDAY SHOULD BRING NOTHING MORE THAN LIGHT
RAIN AND SNOW WITH LITTLE OR NO SNOW ACCUMULATION. TEMPERATURES TO
BEGIN THE PERIOD LOOK TO BE BELOW NORMAL...WITH HIGHS IN THE 40S
DURING THE DAY...AND LOWS TUESDAY NIGHT IN THE LOW TO MID 20S. AN
ARCTIC AIR MASS IS THEN PROGGED TO SETTLE OVER THE REGION MID WEEK.
HIGHS ON WEDNESDAY AND THURSDAY WILL LIKELY NOT MAKE IT OUT OF THE
30S. OVERNIGHT LOWS WEDNESDAY AND THURSDAY NIGHT WILL BE EVEN
CHILLIER...WITH THE MERCURY BOTTOMING OUT AROUND 20 WEDNESDAY
NIGHT...AND THE MID TO UPPER 20S THURSDAY NIGHT.
THE BIG STORY IN THE EXTENDED WILL BE THE WEATHER SYSTEM THAT IS
FORECAST TO SOAK THE AREA TOWARD THE END OF THE WEEK. THERE IS NO
QUESTION THAT A POTENT WEATHER SYSTEM WITH EXTENSIVE PRECIPITATION
WILL AFFECT THE STATE OF KENTUCKY FRIDAY AND SATURDAY. THE QUESTIONS
WITH THIS SYSTEM WILL BE HOW QUICKLY WILL PRECIPITATION MOVE INTO
THE AREA AND HOW MUCH OF THE PRECIP WILL BE IN THE FORM OF SNOW?
RIGHT NOW THE GFS IS MUCH SLOWER AND WARMER THAN THE ECMWF WITH THE
END OF WEEK WEATHER PATTERN. THE GFS HAS ITS LOW MOVING FURTHER
NORTH THAN THE ECMWF. THAT BEING SAID...WITH SO MUCH UNCERTAINTY
INVOLVED...DECIDED TO GO WITH A COMPROMISE BETWEEN THE TWO
MODELS...SLIGHTLY FAVORING THE COLDER ECMWF MODEL. THIS IS BASED ON
THE FACT THAT THE MODELS HAVE BEEN RUNNING A BIT TOO WARM LATELY
WITH REGARDS TO LOW AND MIDDLE LEVEL TEMPERATURES. AFTER A PERIOD OF
MIXED PRECIP THURSDAY EVENING...AN AREA OF LIGHT SNOW IS BEING
FORECAST TO DEVELOP LATE THURSDAY NIGHT THROUGH EARLY FRIDAY
MORNING. THERE COULD BE SOME LIGHT ACCUMULATIONS WITH THIS BAND OF
SNOW AS IT MOVES NORTH...BUT IT WILL LIKELY NOT STAY ON THE GROUND
LONG AS TEMPERATURES RISE INTO THE 40S ON FRIDAY. AN EXTENDED PERIOD
OF GOOD SOAKING RAIN IS EXPECTED FRIDAY THROUGH SATURDAY...WITH THE
POTENTIAL FOR SOME SNOW ALONG AND NORTH OF I-64 FRIDAY NIGHT AND
SATURDAY NIGHT...AS SOME NEAR FREEZING AIR COULD SPILL INTO THAT
AREA EACH NIGHT. AS IS COMMON IN WINTER...THE MODELS WILL NEED TO BE
WATCHED VERY CLOSELY TO SEE WHICH DIRECTION THINGS TREND...MORE RAIN
OR MORE SNOW WILL BE THE QUESTION AS WE MOVE FORWARD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 100 AM EST MON DEC 29 2014
FRONTAL BOUNDARY HAS MOVED SOUTH OF THE REGION TONIGHT WITH SURFACE
LOW RIDING UP ACROSS THE CAROLINA/TENNESSEE BORDER INDICATED BY 03Z
SURFACE ANALYSIS. MOST OF THE HEAVIER RAIN SHOWER ACTIVITY HAS MOVED
SOUTH OF THE REGION TONIGHT...HOWEVER DRIZZLE OR ISOLATED SHOWERS
WILL BE POSSIBLE OVERNIGHT. TAF SITES HAVE BEEN FLUCTUATING TONIGHT
WITH MOST SITES SEEING IFR TO LIFR CONDITIONS. SOME DRIER AIR HAS
BEEN ABLE TO TO MAKE IT INTO NW PORTIONS OF THE CWA WITH SYM CIGS
MVFR...HOWEVER FOG IS EXPECTED TO STILL BE A ISSUE AT MOST SITES AND
COULD BRING LOWER CONDITIONS TO THESE SITES THAT SEE THE HIGHER CIGS.
MOVING INTO TOMORROW MORNING WOULD EXPECT SOME IMPROVEMENTS TO THE
TAF SITES AS FOG LIFTS SLOWLY...BUT MOST SITES ARE ONLY EXPECTED TO
IMPROVE TO MVFR CONDITIONS AS WE MOVE INTO TOMORROW.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JMW
SHORT TERM...SHALLENBERGER
LONG TERM...AR
AVIATION...DJ
AREA FORECAST DISCUSSION
NWS NEW ORLEANS LA
716 AM CST MON DEC 29 2014
...SOUNDING DISCUSSION...
IN RESPONSE TO THE COLD FRONTAL PASSAGE...THE LOW LEVELS HAVE
COOLED OFF SINCE YESTERDAY MORNING. A STABLE PROFILE IS FOUND
WITH POSITIVE LIFTED INDEX AND NO MLCAPE. WINDS ARE LIGHT AND
VARIABLE IN THE LOW LEVELS AND WITH THE LOWEST 1000 FEET OR SO
REMAINING SATURATED ADVECTION FOG HAS FORMED. SOME CLOUDS
ASSOCIATED WITH THE DEPARTING COLD FRONT ARE VISIBLE ON IR
IMAGERY AND ARE LIKELY AROUND 11000 FEET PER NEARLY SATURATED
LAYER AT THAT LEVEL. WINDS BETWEEN 5000 AND 8000 FEET WERE FROM
THE WEST AND ABOVE 8000 FEET WERE MAINLY FROM THE SOUTHWEST. A
PEAK WIND SPEED OF 115 KNOTS WAS LOCATED AT 39500 FEET.
12Z BALLOON INFO: NO ISSUES WITH THE 119 MINUTE FLIGHT THIS MORNING.
THE BALLOON REACHED A HEIGHT OF 21.9 MILES ABOVE THE GROUND BEFORE
BURSTING NEAR AXIS AL 114 MILES DOWNRANGE FROM THE OFFICE.
ANSORGE
&&
.PREV DISCUSSION... /ISSUED 348 AM CST MON DEC 29 2014/
SHORT TERM...
COLD FRONT HAS FINALLY PUSHED OFFSHORE AND IS SLOWLY PROGRESSING
EASTWARD. A BAND OF LIGHT TO MODERATE RAN HAS DEVELOPED ACROSS
PLAQUEMINES PARISH...EXTENDING NORTHEASTWARD TOWARDS THE ALABAMA
COAST. THE HRRR SHOWS THIS ACTIVITY HANGING AROUND FOR A COUPLE MORE
HOURS BEFORE SHIFTING OFFSHORE. THIS COINCIDES WELL WITH LATEST
WATER VAPOR IMAGERY WHICH INDICATES THAT DRIER MID LEVEL AIR SHOULD
BE ARRIVING AT ABOUT THAT SAME TIME. ISOLATED SHOWERS COULD LINGER
FOR A FEW HOURS IN THE MORNING ALONG COASTAL AREAS. OTHERWISE...IT
DOES APPEAR LOW LOW LEVEL STRATUS DECK WILL HANG AROUND ALL DAY AND
TONIGHT AS WELL. HAVE MADE ADJUSTMENTS TO THE ZONES FOR THAT. IN
ADDITION...HAVE KEPT HIGHS A COUPLE DEGREES COOLER THAN MAV GUIDANCE
TO ACCOUNT FOR LESS THAN EXPECTED INSOLATION.
AN UPPER LEVEL TROUGH DROPPING OUT OF CANADA EARLY THIS WEEK WILL
SEND A SECONDARY SURGE OF COLDER AIR TO THE AREA TUESDAY. STRONG
COLD AIR ADVECTION WILL PERSIST FOR AT LEAST A COUPLE DAYS. THIS
WILL DROP TEMPERATURES TO ABOUT 10 DEGREES BELOW NORMAL WED AND
THURS. COULD SEE FREEZE TEMPS FOR LOWS THURSDAY MORNING.
LONG TERM...
MODELS STILL SHOWING AN UPPER LEVEL LOW CLOSING OFF OVER THE DESERT
SOUTHWEST MID WEEK AND TRACKING EASTWARD ACROSS THE CENTRAL PLAINS
THIS WEEKEND. SHOWERS AND THUNDERSTORMS ARE EXPECTED LOCALLY AHEAD
OF THIS FEATURE AS MOISTURE INCREASES ACROSS THE AREA. HAVE BUMPED
UP POPS TO 60 PERCENT ON FRIDAY AND 60-70 PCT FOR SATURDAY.
INSTABILITY LOOKS TO BE DEVELOPING SATURDAY AS LOW LEVELS WARM AND
MID/UPPER LEVEL COOLING TAKES PLACE. A FEW MARGINALLY STRONG TO
SEVERE STORMS COULD DEVELOP BUT THATS STILL SEVERAL DAYS OUT AT THIS
TIME TO KNOW WITH ANY DEGREE OF CERTAINTY. UPPER/SFC LOW PLACEMENT
AMONG OTHER THINGS COULD CHANGE QUITE A BIT BETWEEN NOW AND THEN.
JUST WANTED TO MENTION THE POSSIBILITY.
MEFFER
AVIATION...
A LOW STRATUS DECK WILL REMAIN OVER THE TERMINALS THROUGH THE ENTIRE
FORECAST PERIOD. CEILINGS WILL GENERALLY RANGE FROM 300 TO 800
FEET..RESULTING IN LIFR AND IFR CONDITIONS AT ALL OF THE TERMINALS
THROUGH AROUND 15Z. AFTER 15Z...CONDITIONS SHOULD IMPROVE
SLIGHTLY...WITH CEILINGS GENERALLY RANGING FROM 1000 TO 1500 FEET.
THESE MVFR CONDITIONS WILL PERSIST THROUGH 00Z. HOWEVER...STRATUS
BUILD DOWN WILL OCCUR AFTER 00Z...AS AN ELEVATED INVERSION
STRENGTHENS. A RETURN TO IFR AND LIFR CEILINGS RANGING FROM 300 TO
800 FEET IS EXPECTED BY 03Z. 32
MARINE...
NORTHEAST FLOW OF 10 TO 15 KNOTS WILL RISE INTO SMALL CRAFT EXERCISE
CAUTION RANGE LATE TONIGHT AND TOMORROW AS A COOLER AND DRIER
AIRMASS ADVECTS OVER THE COASTAL WATERS. THIS STRONGER NORTHEAST
FLOW OF 15 TO 20 KNOTS WILL PERSIST THROUGH WEDNESDAY NIGHT. WINDS
WILL VEER TO AN EASTERLY DIRECTION AS THE HIGH SHIFTS TO THE
EAST...AND ANOTHER AREA OF LOW PRESSURE BEGINS TO FORM IN THE
WESTERN GULF OF MEXICO. AS THE LOW SLOWLY MOVES NORTH INTO EASTERN
TEXAS AND WESTERN LOUISIANA FRIDAY AND SATURDAY...WINDS WILL FURTHER
VEER TO THE SOUTHEAST AND REMAIN IN EXERCISE CAUTION RANGE. SEAS
WILL INCREASE TO 4 TO 6 FEET IN THE OUTER WATERS DURING THIS PERIOD. 32
DECISION SUPPORT...
DSS CODE...GREEN.
DEPLOYED...NONE.
ACTIVATION...NONE.
ACTIVITIES...SLURRY SUPPORT
FLOOD WATCH
DECISION SUPPORT SERVICES (DSS) CODE LEGEND
GREEN = NO WEATHER IMPACTS THAT REQUIRE ACTION
BLUE = LONG FUSED WATCH/WARNING/ADVISORY IN EFFECT OR HIGH
VISIBILITY EVENT
YELLOW = HEIGHTENED IMPACTS WITH SHORT FUSED
WATCH/WARNING/ADVISORY ISSUANCES; RADAR SUPPORT
ORANGE = HIGH IMPACTS - SLIGHT TO MODERATE RISK SEVERE; NEARBY
TROPICAL EVENTS; HAZMAT OR OTHER LARGE EPISODES
RED = FULL ENGAGEMENT FOR MODERATE TO HIGH RISK SVR
AND/OR DIRECT TROPICAL THREATS; EVENTS OF NATIONAL
SIGNIFICANCE.
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 54 42 55 33 / 10 10 0 0
BTR 57 44 58 36 / 10 10 0 0
ASD 61 46 60 35 / 10 0 0 0
MSY 60 49 59 42 / 10 0 0 0
GPT 63 47 60 38 / 10 0 0 0
PQL 63 47 61 35 / 10 0 0 0
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
GM...NONE.
MS...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NEW ORLEANS LA
348 AM CST MON DEC 29 2014
.SHORT TERM...
COLD FRONT HAS FINALLY PUSHED OFFSHORE AND IS SLOWLY PROGRESSING
EASTWARD. A BAND OF LIGHT TO MODERATE RAN HAS DEVELOPED ACROSS
PLAQUEMINES PARISH...EXTENDING NORTHEASTWARD TOWARDS THE ALABAMA
COAST. THE HRRR SHOWS THIS ACTIVITY HANGING AROUND FOR A COUPLE MORE
HOURS BEFORE SHIFTING OFFSHORE. THIS COINCIDES WELL WITH LATEST
WATER VAPOR IMAGERY WHICH INDICATES THAT DRIER MID LEVEL AIR SHOULD
BE ARRIVING AT ABOUT THAT SAME TIME. ISOLATED SHOWERS COULD LINGER
FOR A FEW HOURS IN THE MORNING ALONG COASTAL AREAS. OTHERWISE...IT
DOES APPEAR LOW LOW LEVEL STRATUS DECK WILL HANG AROUND ALL DAY AND
TONIGHT AS WELL. HAVE MADE ADJUSTMENTS TO THE ZONES FOR THAT. IN
ADDITION...HAVE KEPT HIGHS A COUPLE DEGREES COOLER THAN MAV GUIDANCE
TO ACCOUNT FOR LESS THAN EXPECTED INSOLATION.
AN UPPER LEVEL TROUGH DROPPING OUT OF CANADA EARLY THIS WEEK WILL
SEND A SECONDARY SURGE OF COLDER AIR TO THE AREA TUESDAY. STRONG
COLD AIR ADVECTION WILL PERSIST FOR AT LEAST A COUPLE DAYS. THIS
WILL DROP TEMPERATURES TO ABOUT 10 DEGREES BELOW NORMAL WED AND
THURS. COULD SEE FREEZE TEMPS FOR LOWS THURSDAY MORNING.
.LONG TERM...
MODELS STILL SHOWING AN UPPER LEVEL LOW CLOSING OFF OVER THE DESERT
SOUTHWEST MID WEEK AND TRACKING EASTWARD ACROSS THE CENTRAL PLAINS
THIS WEEKEND. SHOWERS AND THUNDERSTORMS ARE EXPECTED LOCALLY AHEAD
OF THIS FEATURE AS MOISTURE INCREASES ACROSS THE AREA. HAVE BUMPED
UP POPS TO 60 PERCENT ON FRIDAY AND 60-70 PCT FOR SATURDAY.
INSTABILITY LOOKS TO BE DEVELOPING SATURDAY AS LOW LEVELS WARM AND
MID/UPPER LEVEL COOLING TAKES PLACE. A FEW MARGINALLY STRONG TO
SEVERE STORMS COULD DEVELOP BUT THATS STILL SEVERAL DAYS OUT AT THIS
TIME TO KNOW WITH ANY DEGREE OF CERTAINTY. UPPER/SFC LOW PLACEMENT
AMONG OTHER THINGS COULD CHANGE QUITE A BIT BETWEEN NOW AND THEN.
JUST WANTED TO MENTION THE POSSIBILITY.
MEFFER
&&
.AVIATION...
A LOW STRATUS DECK WILL REMAIN OVER THE TERMINALS THROUGH THE ENTIRE
FORECAST PERIOD. CEILINGS WILL GENERALLY RANGE FROM 300 TO 800
FEET..RESULTING IN LIFR AND IFR CONDITIONS AT ALL OF THE TERMINALS
THROUGH AROUND 15Z. AFTER 15Z...CONDITIONS SHOULD IMPROVE
SLIGHTLY...WITH CEILINGS GENERALLY RANGING FROM 1000 TO 1500 FEET.
THESE MVFR CONDITIONS WILL PERSIST THROUGH 00Z. HOWEVER...STRATUS
BUILD DOWN WILL OCCUR AFTER 00Z...AS AN ELEVATED INVERSION
STRENGTHENS. A RETURN TO IFR AND LIFR CEILINGS RANGING FROM 300 TO
800 FEET IS EXPECTED BY 03Z. 32
&&
.MARINE...
NORTHEAST FLOW OF 10 TO 15 KNOTS WILL RISE INTO SMALL CRAFT EXERCISE
CAUTION RANGE LATE TONIGHT AND TOMORROW AS A COOLER AND DRIER
AIRMASS ADVECTS OVER THE COASTAL WATERS. THIS STRONGER NORTHEAST
FLOW OF 15 TO 20 KNOTS WILL PERSIST THROUGH WEDNESDAY NIGHT. WINDS
WILL VEER TO AN EASTERLY DIRECTION AS THE HIGH SHIFTS TO THE
EAST...AND ANOTHER AREA OF LOW PRESSURE BEGINS TO FORM IN THE
WESTERN GULF OF MEXICO. AS THE LOW SLOWLY MOVES NORTH INTO EASTERN
TEXAS AND WESTERN LOUISIANA FRIDAY AND SATURDAY...WINDS WILL FURTHER
VEER TO THE SOUTHEAST AND REMAIN IN EXERCISE CAUTION RANGE. SEAS
WILL INCREASE TO 4 TO 6 FEET IN THE OUTER WATERS DURING THIS PERIOD. 32
&&
.DECISION SUPPORT...
DSS CODE...GREEN.
DEPLOYED...NONE.
ACTIVATION...NONE.
ACTIVITIES...SLURRY SUPPORT
FLOOD WATCH
DECISION SUPPORT SERVICES (DSS) CODE LEGEND
GREEN = NO WEATHER IMPACTS THAT REQUIRE ACTION
BLUE = LONG FUSED WATCH/WARNING/ADVISORY IN EFFECT OR HIGH
VISIBILITY EVENT
YELLOW = HEIGHTENED IMPACTS WITH SHORT FUSED
WATCH/WARNING/ADVISORY ISSUANCES; RADAR SUPPORT
ORANGE = HIGH IMPACTS - SLIGHT TO MODERATE RISK SEVERE; NEARBY
TROPICAL EVENTS; HAZMAT OR OTHER LARGE EPISODES
RED = FULL ENGAGEMENT FOR MODERATE TO HIGH RISK SVR
AND/OR DIRECT TROPICAL THREATS; EVENTS OF NATIONAL
SIGNIFICANCE.
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 54 42 55 33 / 10 10 0 0
BTR 57 44 58 36 / 10 10 0 0
ASD 61 46 60 35 / 20 0 0 0
MSY 60 49 59 42 / 20 0 0 0
GPT 63 47 60 38 / 20 0 0 0
PQL 63 47 61 35 / 20 0 0 0
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
GM...NONE.
MS...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS BALTIMORE MD/WASHINGTON DC
549 AM EST MON DEC 29 2014
.SYNOPSIS...
WEAK DISTURBANCES WILL RIDE ALONG A COLD FRONT...MAINLY TO OUR
SOUTH...TODAY THROUGH TUESDAY. HIGH PRESSURE WILL BUILD INTO THE EASTERN
HALF OF THE COUNTRY FOR THE SECOND HALF OF THE WEEK. LOW PRESSURE
IS EXPECTED TO AFFECT THE MID ATLANTIC REGION THIS WEEKEND.
&&
.NEAR TERM /THROUGH TUESDAY/...
QUICK UPDATE ON PRECIP TONIGHT INTO TUESDAY...
AS OF 08Z...1055MB SFC HIGH IS NORTH OF CALGARY WHILE AN UPR LOW IS
OVER NRN QUEBEC AND AN UPR TROUGH IS OVER THE INTERMOUNTAIN WEST. A
WEAK COLD FRONT EXTENDS FROM A LOW EAST OF NEWFOUNDLAND TO THE
CAROLINAS. HIGH PRESSURE WILL BUILD NORTH OF THE CWA TODAY...WITH A
NELY FLOW OF 10 MPH OR SO SETTING UP. RAIN CURRENTLY ALONG SOUTHERN
PERIPHERY OF CWA (WITH PATCHY SPRINKLES/LIGHT RAIN UP THROUGH THE DC
METRO AREA) WILL CONTINUE TO DRIFT SOUTH THROUGH TODAY. REDUCED POPS
ACROSS THE BALT-WASH METRO PER RECENT HRRR RUNS AND OBSERVED RADAR
TRENDS. RAIN WILL CONTINUE TO BE LIGHT WITH LESS THAN A TENTH INCH
QPF. MAX TEMPS LOW TO MID 40S UNDER PERSISTENT MID-LEVEL CLOUDS.
ELY COMPONENT WILL PROMOTE PRECIP DEVELOPMENT FOR CNTRL VA BLUE
RIDGE AND AREAS FARTHER WEST. COLDER AIR THERE WILL ALLOW SOME SNOW
ABOVE ABOUT 2500 FT TODAY...LOWERING BELOW 1000 FT TONIGHT.
EXPANDED CHANCE POPS FARTHER NORTHEAST TOWARD THE BALT-WASH METRO
AREA PER 06Z NAM/GFS. LOOKS LIKE SOME AGEOSTROPHIC FORCING ALONG
A BAROCLINIC ZONE WILL AID FORCING IN SPITE OF MSLP APPROACHING
1030MB. . ADDED SOME LIGHT SNOW AMOUNTS ACROSS THE N-CNTRL VA
PIEDMONT. SNOW PROBS UPDATED AS WELL WHICH HIGHLIGHTS THE THREAT
FOR BANDED SNOW WHICH COULD ACCUMULATE ONE TO TWO INCHES FAIRLY
QUICKLY...SHOULD THEY SET UP. CLOUDY ACROSS THE CWA WITH MIN
TEMPS UPR 20S TO LOW 30S (MID 30S FOR NEAR SHORE).
PRECIP SHIFTS SOUTH TUESDAY AS HIGH PRESSURE CONTINUES TO MOVE
INTO THE CWA FROM THE WEST. EXPECT LIGHT NLY FLOW AND MAX TEMPS
UPR 30S TO LOW 40S UNDER CLEARING SKIES.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
HIGH PRES XPCTD TO BUILD INTO THE AREA FOR NEW YRS EVE...SO WX WL
NOT BE A PROBLEM WED NGT OR THE 1ST DAY OF 2015. THE HIGH SHOULD
RMN IN CONTROL OF MID ATLC WX THRU THE END OF THE WK. THIS WL
ALLOW TEMPS TO MODERATE - THU MRNG LOWS WL MAINLY BE IN THE
L20S...BY SAT MRNG ABT TEN DEGS WARMER. THE SAME WL BE TRUE W/
HIGH TEMPS - THU ARND 40...A50 SAT.
&&
.LONG TERM /FRIDAY THROUGH SUNDAY/...
LOW PRES WL BE INFLUENCING THE ERN U.S. OVR THE WKND. THERE IS
DIFFERENCE IN THE MDLS AS TO THE TRAJECTORY OF THE SYSTEM - EURO
HAS IT ON A SRN TRACK WHILE THE GFS TAKES IT INTO THE ERN GRT LKS
ALNG W/ A COLD FNT PUSHING ONTO THE E CST. OBVIOUSLY THIS WL NEED
TO RESOLVED IN THE COMING DAYS. AT THIS MOMENT P-TYPE LOOKS TO BE
LIQUID. IF TEMPS ARE ABLE TO DROP BLO FRZG THEN FZRA WL NEED TO BE
CONSIDERED BUT THAT IS A LONG WAY AWAY.
LOOKING AT THE HEMISPHERIC 500 MB PATTERN OF BOTH THE GFS AND
ECM...THE COLDEST AIR LOOKS TO RMN LOCKED OVR HUDSON BAY INTO NEXT
WK. JAN 5-8 2014 SAW XTRMLY COLD AIR IN THE CWA AND THE ISSUANCE OF
MULTIPLE WIND CHILL ADVISORIES AND WRNGS (ACTUAL WIND CHILL OF -11
AT DCA....BLO -40 IN THE HIGHLANDS). NO REPEAT IN 2015.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
VFR CONDS CONTINUE TO PREVAIL AS COLD FRONT AND ASSOCIATED RAIN
CONTINUES TO MOVE SOUTH.
VFR CONDS XPCTD TUE NGT THRU FRI.
&&
.MARINE...
LIGHT SWLY FLOW VEERS NWLY TODAY AS A COLD FRONT CROSSES THE WATERS
THIS AFTERNOON AND EVENING. COULD BE A NLY SURGE WITH GUSTS AROUND
18 KT LATE TONIGHT. DID NOT RAISE AN SCA DUE TO UNCERTAINTY...BUT
ONE OUT OF SANDY POINT IS POSSIBLE INTO MONDAY.
NO PROBS XPCTD TUE NGT THRU FRI ON THE WATERS.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...
LONG TERM...
AVIATION...
MARINE...
AREA FORECAST DISCUSSION...CORRECTED
NWS BALTIMORE MD/WASHINGTON DC
359 AM EST MON DEC 29 2014
.SYNOPSIS...
WEAK DISTURBANCES WILL RIDE ALONG A COLD FRONT...MAINLY TO OUR
SOUTH...TODAY THROUGH TUESDAY. HIGH PRESSURE WILL BUILD INTO THE EASTERN
HALF OF THE COUNTRY FOR THE SECOND HALF OF THE WEEK. LOW PRESSURE
IS EXPECTED TO AFFECT THE MID ATLANTIC REGION THIS WEEKEND.
&&
.NEAR TERM /TODAY AND TONIGHT/...
AS OF 08Z...1055MB SFC HIGH IS NORTH OF CALGARY WHILE AN UPR LOW IS
OVER NRN QUEBEC AND AN UPR TROUGH IS OVER THE INTERMOUNTAIN WEST. A
WEAK COLD FRONT EXTENDS FROM A LOW EAST OF NEWFOUNDLAND TO THE
CAROLINAS. HIGH PRESSURE WILL BUILD NORTH OF THE CWA TODAY...WITH A
NELY FLOW OF 10 MPH OR SO SETTING UP. RAIN CURRENTLY ALONG SOUTHERN
PERIPHERY OF CWA (WITH PATCHY SPRINKLES/LIGHT RAIN UP THROUGH THE DC
METRO AREA) WILL CONTINUE TO DRIFT SOUTH THROUGH TODAY. REDUCED POPS
ACROSS THE BALT-WASH METRO PER RECENT HRRR RUNS AND OBSERVED RADAR
TRENDS. RAIN WILL CONTINUE TO BE LIGHT WITH LESS THAN A TENTH INCH
QPF. MAX TEMPS LOW TO MID 40S UNDER PERSISTENT MID-LEVEL CLOUDS.
ELY COMPONENT WILL PROMOTE PRECIP DEVELOPMENT FOR CNTRL VA BLUE
RIDGE AND AREAS FARTHER WEST. COLDER AIR THERE WILL ALLOW SOME SNOW
ABOVE ABOUT 2500 FT TODAY...LOWERING TO AROUND 1000 FT TONIGHT.
EXPANDED SNOWFALL AREAS TO INCLUDE DUSTING/0.1 INCH IN THE CNTRL
SHEN VLY...STILL LESS THAN INCH FOR RIDGES. ELSEWHERE DRY AND
CLOUDY...MIN TEMPS UPR 20S TO LOW 30S (MID 30S FOR NEAR SHORE).
&&
.SHORT TERM /TUESDAY/...
PRECIP SHIFTS SOUTH AS 1030MB SFC PRES SHIFTS INTO THE
CWA. LIGHT NLY FLOW AND MAX TEMPS UPR 30S TO LOW 40S UNDER CLEARING
SKIES.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
HIGH PRES XPCTD TO BUILD INTO THE AREA FOR NEW YRS EVE...SO WX WL
NOT BE A PROBLEM WED NGT OR THE 1ST DAY OF 2015. THE HIGH SHOULD
RMN IN CONTROL OF MID ATLC WX THRU THE END OF THE WK. THIS WL
ALLOW TEMPS TO MODERATE - THU MRNG LOWS WL MAINLY BE IN THE
L20S...BY SAT MRNG ABT TEN DEGS WARMER. THE SAME WL BE TRUE W/
HIGH TEMPS - THU ARND 40...A50 SAT.
LOW PRES WL BE INFLUENCING THE ERN U.S. OVR THE WKND. THERE IS
DIFFERENCE IN THE MDLS AS TO THE TRJECTORY OF THE SYSTEM - EURO
HAS IT ON A SRN TRACK WHILE THE GFS TAKES IT INTO THE ERN GRT LKS
ALNG W/ A COLD FNT PUSHING ONTO THE E CST. OBVIOUSLY THIS WL NEED
TO RESOLVED IN THE COMING DAYS. AT THIS MOMENT P-TYPE LOOKS TO BE
LIQUID. IF TEMPS ARE ABLE TO DROP BLO FRZG THEN FZRA WL NEED TO BE
CONSIDERED BUT THAT IS A LONG WAY AWAY.
LOOKING AT THE HEMISPHERIC 500 MB PATTERN OF BOTH THE GFS AND
ECM...THE COLDEST AIR LOOKS TO RMN LOCKED OVR HUDSON BAY INTO NEXT
WK. JAN 5-8 2014 SAW XTRMLY COLD AIR IN THE CWA AND THE ISSUANCE OF
MULTIPLE WIND CHILL ADVSRIES AND WRNGS (ACTUAL WIND CHILL OF -11
AT DCA....BLO -40 IN THE HIGHLANDS). NO REPEAT IN 2015.
&&
.AVIATION /08Z MONDAY THROUGH FRIDAY/...
VFR CONDS CONTINUE TO PREVAIL AS COLD FRONT AND ASSOCIATED RAIN
CONTINUES TO MOVE SOUTH.
VFR CONDS XPCTD TUE NGT THRU FRI.
&&
.MARINE...
LIGHT SWLY FLOW VEERS NWLY TODAY AS A COLD FRONT CROSSES THE WATERS
THIS AFTERNOON AND EVENING. COULD BE A NLY SURGE WITH GUSTS AROUND
18 KT LATE TONIGHT. DID NOT RAISE AN SCA DUE TO UNCERTAINTY...BUT
ONE OUT OF SANDY POINT IS POSSIBLE INTO MONDAY.
NO PROBS XPCTD TUE NGT THRU FRI ON THE WATERS.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.
&&
$$
PRODUCTS...BAJ/WOODY!
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
358 AM EST MON DEC 29 2014
.SYNOPSIS...
WEAK DISTURBANCES WILL RIDE ALONG A COLD FRONT...MAINLY TO OUR
SOUTH...TODAY THROUGH TUESDAY. HIGH PRESSURE WILL BUILD INTO THE EASTERN
HALF OF THE COUNTRY FOR THE SECOND HALF OF THE WEEK. LOW PRESSURE
IS EXPECTED TO AFFECT THE MID ATLANTIC REGION THIS WEEKEND.
&&
.NEAR TERM /TODAY AND TONIGHT/...
AS OF 08Z...1055MB SFC HIGH IS NORTH OF CALGARY WHILE AN UPR LOW IS
OVER NRN QUEBEC AND AN UPR TROUGH IS OVER THE INTERMOUNTAIN WEST. A
WEAK COLD FRONT EXTENDS FROM A LOW EAST OF NEWFOUNDLAND TO THE
CAROLINAS. HIGH PRESSURE WILL BUILD NORTH OF THE CWA TODAY...WITH A
NELY FLOW OF 10 MPH OR SO SETTING UP. RAIN CURRENTLY ALONG SOUTHERN
PERIPHERY OF CWA (WITH PATCHY SPRINKLES/LIGHT RAIN UP THROUGH THE DC
METRO AREA) WILL CONTINUE TO DRIFT SOUTH THROUGH TODAY. REDUCED POPS
ACROSS THE BALT-WASH METRO PER RECENT HRRR RUNS AND OBSERVED RADAR
TRENDS. RAIN WILL CONTINUE TO BE LIGHT WITH LESS THAN A TENTH INCH
QPF. MAX TEMPS LOW TO MID 40S UNDER PERSISTENT MID-LEVEL CLOUDS.
ELY COMPONENT WILL PROMOTE PRECIP DEVELOPMENT FOR CNTRL VA BLUE
RIDGE AND AREAS FARTHER WEST. COLDER AIR THERE WILL ALLOW SOME SNOW
ABOVE ABOUT 2500 FT TODAY...LOWERING TO AROUND 1000 FT TONIGHT.
EXPANDED SNOWFALL AREAS TO INCLUDE DUSTING/0.1 INCH IN THE CNTRL
SHEN VLY...STILL LESS THAN INCH FOR RIDGES. ELSEWHERE DRY AND
CLOUDY...MIN TEMPS UPR 20S TO LOW 30S (MID 30S FOR NEAR SHORE).
&&
.SHORT TERM /TUESDAY/...
PRECIP SHIFTS SOUTH AS 1030MB SFC PRES SHIFTS INTO THE
CWA. LIGHT NLY FLOW AND MAX TEMPS UPR 30S TO LOW 40S UNDER CLEARING
SKIES.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
HIGH PRES XPCTD TO BUILD INTO THE AREA FOR NEW YRS EVE...SO WX WL
NOT BE A PROBLEM WED NGT OR THE 1ST DAY OF 2015. THE HIGH SHOULD
RMN IN CONTROL OF MID ATLC WX THRU THE END OF THE WK. THIS WL
ALLOW TEMPS TO MODERATE - THU MRNG LOWS WL MAINLY BE IN THE
L20S...BY SAT MRNG ABT TEN DEGS WARMER. THE SAME WL BE TRUE W/
HIGH TEMPS - THU ARND 40...A50 SAT.
LOW PRES WL BE INFLUENCING THE ERN U.S. OVR THE WKND. THERE IS
DIFFERENCE IN THE MDLS AS TO THE TRJECTORY OF THE SYSTEM - EURO
HAS IT ON A SRN TRACK WHILE THE GFS TAKES IT INTO THE ERN GRT LKS
ALNG W/ A COLD FNT PUSHING ONTO THE E CST. OBVIOUSLY THIS WL NEED
TO RESOLVED IN THE COMING DAYS. AT THIS MOMENT P-TYPE LOOKS TO BE
LIQUID. IF TEMPS ARE ABLE TO DROP BLO FRZG THEN FZRA WL NEED TO BE
CONSIDERED BUT THAT IS A LONG WAY AWAY.
LOOKING AT THE HEMISPHERIC 500 MB PATTERN OF BOTH THE GFS AND
ECM...THE COLDEST AIR LOOKS TO RMN LOCKED OVR HUDSON BAY INTO NEXT
WK. JAN 5-8 2014 SAW XTRMLY COLD AIR IN THE CWA AND THE ISSUANCE OF
MULTIPLE WIND CHILL ADVSRIES AND WRNGS (ACTUAL WIND CHILL OF -11
AT DCA....BLO -40 IN THE HIGHLANDS). NO REPEAT IN 2015.
&&
.AVIATION /08Z MONDAY THROUGH FRIDAY/...
VFR CONDS XPCTD TUE NGT THRU FRI.
&&
.MARINE...
NO PROBS XPCTD TUE NGT THRU FRI ON THE WATERS.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.
&&
$$
PRODUCTS...BAJ/WOODY!
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
427 PM EST MON DEC 29 2014
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 403 PM EST MON DEC 29 2014
WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD MID/UPPER LEVEL TROUGH
EXTENDING FROM NRN QUEBEC THROUGH THE NRN PLAINS INTO THE ROCKIES.
THE NEXT SIGNIFICANT UPSTREAM SHORTWAVE TROUGH WAS DROPPING SOUTH
THROUGH NRN SASK/MANITOBA. AT THE SFC...1054 MB ARCTIC HIGH PRES OVER
ALBERTA EXTENDED INTO THE NRN PLAINS AND UPPER MS VALLEY AND NRN
LAKES RESULTING IN A FLOW OF VERY COLD AIR ACROSS LAKE SUPERIOR ON
NW WINDS. DESPITE 850 MB TEMPS NEAR -21C...LES HAS BEEN LIMITED BY
THE VERY DRY UPSTREAM CONDITIONS AS THE BACK EDGE OF THE CLOUDS WAS
CLOSER TO THE MI SHORE IN THE WEST AND NEAR THE CENTER OF THE NRN
LAKE. RADAR SHOWED MAINLY WEAK WIND PARALLEL BANDS INTO THE ERN
CWA.
TONIGHT...WITH THE LOSS OF DAYTIME MIXING AND ONSET OF LAND BREEZES
THE LES MAY BECOME BETTER ORGANIZED. THE PERSISTENT 290-300 FLOW LES
IS EXPECTED TO CONTINUE BUT WILL BE LIMITED BY 4K FT INVERSION
HEIGHTS AND A LACK OF ANY SUSTAINED AREAS OF LOW LEVEL CONV. THE LONGER
FETCH INTO THE EAST WILL SUPPORT SNOWFALL AMOUNTS IN THE 2 TO 4 INCH
RANGE WITH SLR VALUES NEAR 25/1...E OF MUNISING WHILE OVER THE WEST
ONLY 1 TO 3 INCH AMOUNTS ARE EXPECTED. WIND CHILL VALUES OVER THE
INTERIOR WEST COULD FALL INTO THE -20 TO -25 RANGE AS SFC TEMPS DROP
TO AROUND -8F. HOWEVER...WINDS SHOULD REMAIN LESS THAN 10 MPH.
TUESDAY...EXPECT THE WINDS TO BACK MORE WRLY AHEAD OF THE
SASK/MANITOBA SHORTWAVE TROUGH...ESPECIALLY IN THE AFTERNOON.
OTHERWISE...LIGHT TO MODERATE WNW FLOW LES WILL CONTINUE WITH 850 MB
TEMPS REMAINING NEAR -22C AND INVERSION HEIGHTS AROUND 4K FT. THE
STRONGEST LOW LEVEL CONV...INFLUENCED BY LAKE-INDUCED TROUGHING IS
EXPECTED OVER THE ERN LAKE WITH SOME STRONGER BANDS POSSIBLE
CLIPPING THE NE PORTION OF LUCE COUNTY. FOR NOW...EXPECT ADDITIONAL
ACCUMULATIONS IN THE 2 TO 4 INCH RANGE E OF P53 AND 1 TO 3 INCHES
INTO THE WEST.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 426 PM EST MON DEC 29 2014
A BROAD UPPER TROUGH OVER CANADA AND THE GREAT LAKES REGION WILL
LEAD TO BELOW NORMAL TEMPERATURES AND PERIODS OF LAKE EFFECT SNOW
THROUGH THE FIRST WEEK OF 2015.
AT THE START OF THE PERIOD...THE AREA WILL STILL BE BETWEEN A
STRONG HIGH OVER WESTERN NEBRASKA AND A LOW JUST TO THE NORTH OF
HUDSON BAY. ALOFT...A SHORTWAVE WILL JUST BE DEPARTING THE AREA AND
BRINGING ONE LAST SURGE OF -21C 850MB TEMPS TO THE AREA.
THUS...EXPECT NORTHWEST FLOW LAKE EFFECT TO STILL BE ONGOING
TUESDAY EVENING. A SURFACE TROUGH DIVING SOUTHEAST FROM THE HUDSON
BAY LOW WILL LEAD TO BACKING FLOW ON TUESDAY NIGHT INTO WEDNESDAY
MORNING...SHIFTING THE LAKE EFFECT TO THE WESTERLY FLOW AREAS (THE
KEWEEANW AND RIGHT ALONG THE LAKE SUPERIOR SHORELINE EAST OF
MUNISING). SNOWFALL AMOUNTS TUESDAY NIGHT CONTINUE TO LOOK LIGHT
AND FLUFFY AS INVERSION HEIGHTS ARE STILL IN THE 4-5KFT RANGE WITH
MUCH OF THE CLOUD LAYER IN THE DGZ. WILL FOLLOW THE SNOWFALL
AMOUNTS SEEN OVER THE LAST 12/24HRS AND HAVE THEM BE IN THE
1-4IN/12HRS RANGE.
TUESDAY NIGHT WILL BE ANOTHER COLD NIGHT AWAY FROM THE LAKE EFFECT
CLOUDS...WITH LOWS FALLING INTO THE SINGLE DIGITS AND LOWER TEENS
BELOW ZERO. WIND CHILLS WILL BECOME A CONCERN LATE IN THE NIGHT
INTO WEDNESDAY MORNING...AS THE WEST TO SOUTHWEST WINDS BEGIN TO
INCREASE WITH THE TIGHTENING PRESSURE GRADIENT. WHILE THIS WILL
LIKELY INCREASE MIXING AND IN TURN WARM TEMPS SLIGHTLY (HELPED BY
SOME MID CLOUDS MOVING IN)...THERE WILL STILL BE A PERIOD LATE
TUESDAY NIGHT INTO WEDNESDAY MORNING WHERE WIND CHILL VALUES WILL BE
IN THE -20 TO -30 DEGREE RANGE OVER THE INTERIOR LOCATIONS. WILL
CONTINUE TO MENTION THIS IN THE HWO AND AN ADVISORY MAY BEEN
NEEDED TOMORROW.
WITH THE LOW LEVEL WINDS TRYING TO BACK TOWARDS THE SOUTHWEST
DURING THE DAY WEDNESDAY...DID TRY TO SHOW BETTER TIMING ON THE
LAKE EFFECT SNOW. EXPECT IT TO TRY TO SHIFT OVER THE FAR NORTHERN
PART OF THE KEWEENAW BY MID DAY AND WELL OFFSHORE OVER THE
EAST. WINDS WILL BECOME QUITE GUSTY DURING THIS PERIOD...WITH MUCH
OF UPPER MICHIGAN EXPERIENCING GUSTS IN THE 25 TO 35MPH RANGE. BUT
OVER THE KEWEENAW PENINSULA AND CLOSER TO THE TIGHTER PRESSURE
GRADIENT...WOULD EXPECT GUSTS TO AT LEAST 40 MPH AND AT TIMES
45-50MPH. THESE WINDS COMBINED WITH THE FLUFFY LAKE EFFECT SEEN
OVER THE LAST COUPLE OF DAYS WILL LIKELY LEAD TO SIGNIFICANT
BLOWING SNOW DEVELOPING THROUGH THE DAY WEDNESDAY. THEN...AS STRONG
SHORTWAVE DIVES SOUTHEAST ACROSS THE UPPER GREAT LAKES REGION DURING
THE AFTERNOON AND THE SURFACE TROUGH DURING THE EARLY
EVENING...EXPECT WINDS TO SHIFT BACK TO THE WEST AND REFOCUS THE
LAKE EFFECT IN THE WESTERLY WIND AREAS. THINK THERE COULD BE A
PERIOD OF MODERATE SNOW AS THE WINDS TURN TO THE WEST...DUE TO
INVERSION HEIGHTS RISING TO 7KFT AND MUCH OF THE CLOUD STILL IN THE
DGZ. THERE ARE A COUPLE DOWNSIDES TO HIGHER SNOWFALL AMOUNTS (TIED
TO THE STRONG WINDS)...BUT THERE WILL STILL BE VERY POOR CONDITIONS
OVER THE KEWEENAW. FIRST...THE HIGH WINDS WILL LIMIT THE RESIDENCE
TIME OVER THE WESTERN LAKE AS THEY SHIFT TO THE WEST. SECOND...THE
STRONG WINDS WILL BREAK UP THE DENDRITES FROM THE FAVORABLE CLOUD
LAYER AND LEAD TO SMALLER/FRACTURED FLAKES. WHILE THIS WILL LIMIT
SNOWFALL AMOUNTS...IT WILL BE MORE EFFECTIVE AT REDUCING
VISIBILITIES AND WHEN COMBINED WITH THE BLOWING SNOW...WOULD EXPECT
VISIBILITIES BELOW 1/4 MILE AT TIMES LATE WEDNESDAY AFTERNOON INTO
WEDNESDAY NIGHT. WILL CONTINUE TO MENTION THESE POOR CONDITIONS FOR
THE KEWEENAW IN THE HWO.
EXPECT NORTHWEST FLOW LAKE EFFECT TO REESTABLISH ON THURSDAY FOR
AREAS DOWNSTREAM FROM LAKE SUPERIOR. ELSEWHERE IN THE U.P...MODELS
DIFFER IN THEIR SOLUTIONS ON POTENTIAL SHORTWAVES ZIPPING
EAST-SOUTHEAST ACROSS THE AREA. AT TIMES...MODELS HAVE SHOWN LIGHT
SNOW ASSOCIATED WITH THESE QUICK WAVES THURSDAY AND AGAIN FRIDAY.
BOTH STRENGTH AND LOCATIONS HAS NOT BEEN CONSISTENT IN THE MODELS
OVER THE LAST 24 HOURS...SO WILL FOCUS LARGELY ON LAKE EFFECT
TURNING TO THE WESTERLY WIND LOCATIONS AND SHOW SLIGHT CHANCES
ELSEWHERE.
THE UNCERTAINTY CONTINUES INTO THE WEEKEND...AS MODELS DIFFER ON HOW
THE CLOSED UPPER LOW THAT DEVELOPS OVER THE SOUTHWEST CONUS TUESDAY
INTERACTS WITH THE NORTHERN STREAM JET AS IT SHIFTS EAST ACROSS THE
SOUTHERN CONUS. THE 12Z GFS/GEM SOLUTIONS MERGE THE UPPER LOW WITH
A MORE AMPLIFIED NORTHERN STREAM TROUGH AND THEN LIFT IT AND A
DEVELOPING SURFACE LOW NORTHEAST THROUGH THE LOWER GREAT LAKES
SATURDAY NIGHT. MEANWHILE...THE 12Z ECMWF AND ITS ENSEMBLE MEMBERS
SHOW A MUCH FLATTER NORTHERN STREAM TROUGH AND DON/T MERGE THE
WAVES UNTIL THE EAST COAST ON SUNDAY. THAT WOULD LEAD TO MORE OF A
NORTHERLY FLOW LAKE EFFECT FOR THE AREA. THIS WILL DEFINITELY BE
SOMETHING TO WATCH OVER THE COMING DAYS. EVEN IF THERE ISN/T A LOW
MOVING THROUGH THE LOWER GREAT LAKES...TEMPERATURES WILL BE COLD
ENOUGH FOR LAKE EFFECT SNOW AND WILL CONTINUE TO SHOW THE POTENTIAL
IN THE GRIDS FOR AREAS NEAR LAKE SUPERIOR.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 103 PM EST MON DEC 29 2014
EXPECT MAINLY MVFR CONDITIONS AT IWD/CMX THROUGH THE PERIOD...WITH
SLIGHTLY BETTER CONDITIONS AT SAW.
DESPITE A RIDGE OF STRONG HIGH PRESSURE WORKING IN FROM SW
CANADA...COLD AIR ON NORTHWEST WINDS OVER THE RELATIVELY WARM LAKE
SUPERIOR WATERS WILL KEEP LES GOING AT IWD AND CMX. ALTHOUGH THIS
WIND DIRECTION IS NOT THE BEST FOR SAW TO GET SNOW...OFF AND ON
LIGHT SNOW SHOWERS OR FLURRIES ARE POSSIBLE. EXPECT DAYTIME HEATING TO
HELP DISRUPT SOME OF THE STRONGER BANDS TODAY...BEFORE ANOTHER UPPER
LEVEL DISTURBANCE HELPS BOOST THE POTENTIAL FOR LAKE EFFECT SNOW
SHOWERS AT CMX ONCE AGAIN. AT THAT POINT WINDS OVER N WI AND FAR W
UPPER MI SHOULD BECOME MORE WRLY...LIMITING POTENTIAL FOR MUCH MORE
THAN FLURRIES AT IWD OVERNIGHT.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 403 PM EST MON DEC 29 2014
EXPECT HEAVY FREEZING SPRAY BY TUESDAY AFTERNOON AND GALES FROM LATE
TUESDAY NIGHT THROUGH THURSDAY MORNING.
A RIDGE ACROSS THE UPPER GREAT LAKES WILL BUILD TUESDAY...AS VERY
STRONG ARCTIC HIGH PRESSURE INITIALLY AT 31.3 INCHES OVER SW CANADA
SINKS ACROSS MONTANA. LOOK FOR THE RIDGE OVER LAKE SUPERIOR TO SINK
SOUTH TUESDAY NIGHT. THIS WILL BE AS A HUDSON BAY LOW DRAGS A TROUGH
ACROSS LAKE SUPERIOR. THE LOW WILL DEEPEN OVER S HUDSON BAY
WEDNESDAY NIGHT AS IT BRINGS A REINFORCING TROUGH ACROSS LAKE
SUPERIOR. W GALES OF 35-45KTS ARE STILL ANTICIPATED /ALONG WITH
HEAVY FREEZING SPRAY TUESDAY NIGHT THROUGH THURSDAY MORNING AS
THE PRESSURE GRADIENT TIGHTENS BETWEEN THE EXITING HIGH TO THE S AND
STRONG LOW TO THE N. LOOK FOR THE LOW TO SHIFT ACROSS N QUEBEC AND
WEAKEN SIGNIFICANTLY THURSDAY NIGHT. HIGH PRESSURE WILL THEN BUILD
SE ACROSS SASKATCHEWAN AND S MANITOBA ON THURSDAY AND FRIDAY AS A
RIDGE TRACKS ACROSS THE UPPER GREAT LAKES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING FROM 1 PM EST /NOON CST/ TUESDAY TO
1 PM EST /NOON CST/ THURSDAY FOR LSZ240>245-248>251-263-
265>267.
GALE WARNING FROM 1 AM WEDNESDAY TO 1 PM EST THURSDAY FOR
LSZ264>267.
HEAVY FREEZING SPRAY WARNING FROM 7 PM EST /6 PM CST/ TUESDAY TO
7 AM EST /6 AM CST/ THURSDAY FOR LSZ162.
GALE WARNING FROM 1 AM EST /MIDNIGHT CST/ WEDNESDAY TO 7 AM EST
/6 AM CST/ THURSDAY FOR LSZ162-263.
HEAVY FREEZING SPRAY WARNING FROM 1 AM TUESDAY TO 1 PM EST
THURSDAY FOR LSZ264.
GALE WARNING FROM 1 AM EST /MIDNIGHT CST/ TO 7 PM EST /6 PM CST/
WEDNESDAY FOR LSZ241>245.
HEAVY FREEZING SPRAY WARNING FROM 1 AM WEDNESDAY TO 1 PM EST
THURSDAY FOR LSZ246-247.
LAKE MICHIGAN...
HEAVY FREEZING SPRAY WARNING FROM 10 AM WEDNESDAY TO 1 PM EST
THURSDAY FOR LMZ221-248-250.
&&
$$
SHORT TERM...JLB
LONG TERM...SRF
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
404 PM EST MON DEC 29 2014
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 403 PM EST MON DEC 29 2014
WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD MID/UPPER LEVEL TROUGH
EXTENDING FROM NRN QUEBEC THROUGH THE NRN PLAINS INTO THE ROCKIES.
THE NEXT SIGNIFICANT UPSTREAM SHORTWAVE TROUGH WAS DROPPING SOUTH
THROUGH NRN SASK/MANITOBA. AT THE SFC...1054 MB ARCTIC HIGH PRES OVER
ALBERTA EXTENDED INTO THE NRN PLAINS AND UPPER MS VALLEY AND NRN
LAKES RESULTING IN A FLOW OF VERY COLD AIR ACROSS LAKE SUPERIOR ON
NW WINDS. DESPITE 850 MB TEMPS NEAR -21C...LES HAS BEEN LIMITED BY
THE VERY DRY UPSTREAM CONDITIONS AS THE BACK EDGE OF THE CLOUDS WAS
CLOSER TO THE MI SHORE IN THE WEST AND NEAR THE CENTER OF THE NRN
LAKE. RADAR SHOWED MAINLY WEAK WIND PARALLEL BANDS INTO THE ERN
CWA.
TONIGHT...WITH THE LOSS OF DAYTIME MIXING AND ONSET OF LAND BREEZES
THE LES MAY BECOME BETTER ORGANIZED. THE PERSISTENT 290-300 FLOW LES
IS EXPECTED TO CONTINUE BUT WILL BE LIMITED BY 4K FT INVERSION
HEIGHTS AND A LACK OF ANY SUSTAINED AREAS OF LOW LEVEL CONV. THE LONGER
FETCH INTO THE EAST WILL SUPPORT SNOWFALL AMOUNTS IN THE 2 TO 4 INCH
RANGE WITH SLR VALUES NEAR 25/1...E OF MUNISING WHILE OVER THE WEST
ONLY 1 TO 3 INCH AMOUNTS ARE EXPECTED. WIND CHILL VALUES OVER THE
INTERIOR WEST COULD FALL INTO THE -20 TO -25 RANGE AS SFC TEMPS DROP
TO AROUND -8F. HOWEVER...WINDS SHOULD REMAIN LESS THAN 10 MPH.
TUESDAY...EXPECT THE WINDS TO BACK MORE WRLY AHEAD OF THE
SASK/MANITOBA SHORTWAVE TROUGH...ESPECIALLY IN THE AFTERNOON.
OTHERWISE...LIGHT TO MODERATE WNW FLOW LES WILL CONTINUE WITH 850 MB
TEMPS REMAINING NEAR -22C AND INVERSION HEIGHTS AROUND 4K FT. THE
STRONGEST LOW LEVEL CONV...INFLUENCED BY LAKE-INDUCED TROUGHING IS
EXPECTED OVER THE ERN LAKE WITH SOME STRONGER BANDS POSSIBLE
CLIPPING THE NE PORTION OF LUCE COUNTY. FOR NOW...EXPECT ADDITIONAL
ACCUMULATIONS IN THE 2 TO 4 INCH RANGE E OF P53 AND 1 TO 3 INCHES
INTO THE WEST.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 603 AM EST MON DEC 29 2014
WATER VAPOR LOOP AND RUC ANALYSIS SHOWS STRONGLY AMPLIFIED PATTERN
TAKING SHAPE ACROSS NAMERICA WITH RIDGE OVER THE ERN PACIFIC INTO
WRN CANADA/ALASKA AND A BROAD DOWNSTREAM TROF OVER MUCH OF CENTRAL
AND ERN CANADA INTO THE ERN 2/3RDS OF THE CONUS. MODELS INDICATE
THAT THIS PATTERN WILL HOLD AT LEAST INTO MID WEEK ALLOWING FOR THE
BUILDUP AND EXPANSION OF ARCTIC AIR ACROSS CANADA THAT WILL SPILL S
INTO THE CONUS...SIMILAR TO THE PATTERN OBSERVED MOST OF LAST WINTER
AND LAST MONTH. THIS PATTERN WILL RESULT IN MUCH BELOW NORMAL TEMPS
OVER THE NEXT SEVERAL DAYS AND PERSISTENT LAKE EFFECT SNOW FOR THE
NW TO W WIND SNOW BELTS DOWNWIND OF LAKE SUPERIOR. MODELS DIFFER
WITH HANDLING OF CUT OFF LOW WHICH DEVELOPS OVER THE SW CONUS TOWARD
THE MIDDLE OF THE WEEK. BOTH THE ECMWF AND GEM-NH SHOW THE REMNANTS
OF THIS LOW EJECTING DUE E BY NEXT WEEKEND IN SRN BRANCH AND NOT
REALLY IMPACTING THE GREAT LAKES REGION. THE GFS MEANWHILE HAS THE
REMNANTS OF THE LOW EJECTING NE AND PHASING WITH NRN BRANCH AS IT
DEVELOPS A RAPIDLY DEEPENING STORM SYSTEM OVER THE CENTRAL/LOWER
GREAT LAKES BY NEXT SUNDAY. IT WILL BE WORTH MONITORING MODEL TRENDS
WITH THIS SYSTEM AS ANY TREND TOWARD THE 00Z GFS SOLN WOULD SIGNAL
PERHAPS A MUCH MORE SIGNIFICANT IMPACT ON OUR WEATHER FOR NEXT
WEEKEND.
BEGINNING TUE AND TUE NIGHT...THE COLDEST AIR WITH THE INITIAL SURGE
OF ARCTIC AIR WILL SETTLE OVER THE AREA LATE TUE/TUE NIGHT WHEN
850MB TEMPS BOTTOM OUT AROUND -23C. THIS WILL RESULT IN TUE LIKELY
BEING THE COLDEST DAY THIS WEEK FOR MOST AREAS. MAX TEMPS IN GENERAL
WILL RANGE FROM NEAR ZERO FAR WEST TO THE LOW TO MID TEENS EAST.
SUBZERO MIN TEMPS WILL BE THE RULE TUE NIGHT IN THE INTERIOR AWAY
FROM LAKE EFFECT CLOUDS/SNOW WITH TEMPS IN THE INTERIOR W HALF
SLIPPING TO -10F OR COLDER. WINDS BACKING MORE WESTERLY WILL RESULT
IN LESS LAKE EFFECT CLOUDS/SHSN COVERAGE OVER UPPER MI. COMBINED
WITH SOME INCREASE IN WINDS...WIND CHILLS WILL DROP INTO THE -15 TO
-30F RANGE TUE NIGHT INTO WED MORNING. WITH SUCH COLD AIR...NUMEROUS
SNOW SHOWERS WILL CONTINUE IN THE SNOW BELTS FAVORED BY NW TO W
WINDS. NAM/GFS FCST SOUNDINGS SHOW INVERSIONS AT 4-5KFT...SO EXPECT
LES OVERALL TO BE ON THE LIGHT SIDE (GENERALLY 1-4IN/12HRS).
HOWEVER...THERE COULD BE SOME LOCALLY HIGHER AMOUNTS EAST (PERHAPS
ADVISORY LVL) WHERE FETCH ACROSS THE LAKE IS MAXIMIZED..ALLOWING FOR
MORE LAKE MODERATION AND BETTER POSITIONING OF DGZ WITHIN
CONVECTIVE LAYER. SHORTWAVE TROF SWINGING ACROSS THE AREA ON TUE
WILL HAVE SOME IMPACT ON INCREASING MOISTURE DEPTH/RAISING INVERSION
HEIGHTS MAINLY TUE AFTERNOON WHICH COULD RESULT IN A SPIKE IN
LES COVERAGE/INTENSITY FOR A TIME. SO...DAYLIGHT HRS ON TUE PROBABLY
OFFER THE BEST POTENTIAL FOR LES TO PRODUCE ADVY LEVEL ACCUMULATIONS
IN THE SNOW BELTS FAVORED BY NW WINDS.
ON NEW YEARS EVE DAY...LOW-LEVEL WINDS WILL BACK TO THE WSW OR EVEN
SW IN RESPONSE TO THE NEXT SHORTWAVE TROF SWINGING SE THRU MANITOBA
INTO NRN ONTARIO. THIS WILL CAUSE LES TO SHIFT OFFSHORE OF UPPER MI.
HOWEVER...UP AT 850MB...WINDS REMAIN OUT OF THE W. SO...LES WILL
LIKELY CONTINUE TO AFFECT THE KEWEENAW PENINSULA. TIGHTENING PRES
GRADIENT BTWN HIGH PRES OVER THE CNTRL/SRN PLAINS AND LOW PRES OVER
HUDSON BAY WILL RESULT IN INCREASING SFC WINDS...ESPECIALLY OVER THE
EXPOSED KEWEENAW WHERE 950MB WINDS ARE FCST AT 35-40KT. WOULD NOT BE
SURPRISED TO SEE BLIZZARD TO NEAR BLIZZARD CONDITIONS MET OVER
KEWEENAW IF LES COVERAGE REMAINS NUMEROUS OR GREATER...WHICH NAM
SNDGS SUGGEST A GOOD POTENTIAL FOR LES ENHANCEMENT WITH DEEPENING
MOISTURE PROFILE AND DEEP CONVECTION LAYER TROUGH DGZ...ESPECIALLY
LATE WED AFTERNOON INTO NEW YEARS EVE NIGHT. WILL HIGHLIGHT THIS
POTENTIAL IN HWO.
NEXT ARCTIC COLD FRONT ASSOCIATED WITH MANITOBA SHORTWAVE WILL
SWING ACROSS THE AREA EARLY ON NEW YEARS DAY...ENHANCING LES FOR A
TIME IN NW LAKE SUPERIOR SNOWBELTS AND PROBABLY BRINGING ISOLD/SCT
-SHSN TO THE REMAINDER OF THE AREA.
LES WILL CONTINUE ON INTO FRI UNDER COLD AIR MASS...BUT THERE IS
STILL DECENT MODEL AGREEMENT THAT WINDS WILL BACK FRI AS HIGH PRES
RIDGE SLIPS E OF THE AREA AND PRES FALLS SPREAD OUT OVER THE PLAINS.
THE BACKING WINDS AND RESULTING DEVELOPING WAA/ISENTROPIC ASCENT
REGIME WILL ALLOW FOR MORE WIDESPREAD SNOW TO DEVELOP OVER THE NRN
PLAINS AND THEN SPREAD E INTO THE UPPER LAKES.
ON INTO SAT/SUN...MUCH WILL DEPEND ON EVOLUTION OF THE CLOSED LOW
THAT WILL BE OVER THE SW STATES MIDWEEK AS STATED EARLIER IN
DISCUSSION. 00Z GFS SOLN OF DEVELOPING MORE PHASED DEEP STORM SYSTEM
OVER THE CENTRAL GREAT LAKES BY NEXT WEEKEND APPEARS TO BE SOMEWHAT
OF AN OUTLIER BASED ON PREVIOUS GFS RUNS AND THE REST OF THE MODEL
GUIDANCE. I AM MORE INCLINED TO LEAN TOWARD BLEND OF MORE CONSISTENT
00Z ECMWF AND GEM-NH SOLN WHICH KEEPS REMNANTS OF CLOSED LOW MUCH
FARTHER SOUTH. THIS SOLN WOULD SHOW NRN BRANCH REMAINING DOMINANT
OVER UPPER LAKES WITH A RETURN TO COLDER AIR (NEAR -20C AT 850 MB)
FOR NEXT WEEKEND BEHIND FRI/S SYSTEM ALLOWING FOR MORE PERIODS OF
LES FOR THE NW SNOWBELTS ALONG LAKE SUPERIOR. LOOKS LIKE NRN BRANCH
WILL REMAIN ACTIVE INTO EARLY NEXT WEEK AS WELL BRINGING PERIODIC
CLIPPER SYSTEMS THROUGH AREA REINFORCING ARCTIC AIRMASS IN
PLACE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 103 PM EST MON DEC 29 2014
EXPECT MAINLY MVFR CONDITIONS AT IWD/CMX THROUGH THE PERIOD...WITH
SLIGHTLY BETTER CONDITIONS AT SAW.
DESPITE A RIDGE OF STRONG HIGH PRESSURE WORKING IN FROM SW
CANADA...COLD AIR ON NORTHWEST WINDS OVER THE RELATIVELY WARM LAKE
SUPERIOR WATERS WILL KEEP LES GOING AT IWD AND CMX. ALTHOUGH THIS
WIND DIRECTION IS NOT THE BEST FOR SAW TO GET SNOW...OFF AND ON
LIGHT SNOW SHOWERS OR FLURRIES ARE POSSIBLE. EXPECT DAYTIME HEATING TO
HELP DISRUPT SOME OF THE STRONGER BANDS TODAY...BEFORE ANOTHER UPPER
LEVEL DISTURBANCE HELPS BOOST THE POTENTIAL FOR LAKE EFFECT SNOW
SHOWERS AT CMX ONCE AGAIN. AT THAT POINT WINDS OVER N WI AND FAR W
UPPER MI SHOULD BECOME MORE WRLY...LIMITING POTENTIAL FOR MUCH MORE
THAN FLURRIES AT IWD OVERNIGHT.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 403 PM EST MON DEC 29 2014
EXPECT HEAVY FREEZING SPRAY BY TUESDAY AFTERNOON AND GALES FROM LATE
TUESDAY NIGHT THROUGH THURSDAY MORNING.
A RIDGE ACROSS THE UPPER GREAT LAKES WILL BUILD TUESDAY...AS VERY
STRONG ARCTIC HIGH PRESSURE INITIALLY AT 31.3 INCHES OVER SW CANADA
SINKS ACROSS MONTANA. LOOK FOR THE RIDGE OVER LAKE SUPERIOR TO SINK
SOUTH TUESDAY NIGHT. THIS WILL BE AS A HUDSON BAY LOW DRAGS A TROUGH
ACROSS LAKE SUPERIOR. THE LOW WILL DEEPEN OVER S HUDSON BAY
WEDNESDAY NIGHT AS IT BRINGS A REINFORCING TROUGH ACROSS LAKE
SUPERIOR. W GALES OF 35-45KTS ARE STILL ANTICIPATED /ALONG WITH
HEAVY FREEZING SPRAY TUESDAY NIGHT THROUGH THURSDAY MORNING AS
THE PRESSURE GRADIENT TIGHTENS BETWEEN THE EXITING HIGH TO THE S AND
STRONG LOW TO THE N. LOOK FOR THE LOW TO SHIFT ACROSS N QUEBEC AND
WEAKEN SIGNIFICANTLY THURSDAY NIGHT. HIGH PRESSURE WILL THEN BUILD
SE ACROSS SASKATCHEWAN AND S MANITOBA ON THURSDAY AND FRIDAY AS A
RIDGE TRACKS ACROSS THE UPPER GREAT LAKES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING FROM 1 PM EST /NOON CST/ TUESDAY TO
1 PM EST /NOON CST/ THURSDAY FOR LSZ240>245-248>251-263-
265>267.
GALE WARNING FROM 1 AM WEDNESDAY TO 1 PM EST THURSDAY FOR
LSZ264>267.
HEAVY FREEZING SPRAY WARNING FROM 7 PM EST /6 PM CST/ TUESDAY TO
7 AM EST /6 AM CST/ THURSDAY FOR LSZ162.
GALE WARNING FROM 1 AM EST /MIDNIGHT CST/ WEDNESDAY TO 7 AM EST
/6 AM CST/ THURSDAY FOR LSZ162-263.
HEAVY FREEZING SPRAY WARNING FROM 1 AM TUESDAY TO 1 PM EST
THURSDAY FOR LSZ264.
GALE WARNING FROM 1 AM EST /MIDNIGHT CST/ TO 7 PM EST /6 PM CST/
WEDNESDAY FOR LSZ241>245.
HEAVY FREEZING SPRAY WARNING FROM 1 AM WEDNESDAY TO 1 PM EST
THURSDAY FOR LSZ246-247.
LAKE MICHIGAN...
HEAVY FREEZING SPRAY WARNING FROM 10 AM WEDNESDAY TO 1 PM EST
THURSDAY FOR LMZ221-248-250.
&&
$$
SHORT TERM...JLB
LONG TERM...VOSS
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
104 PM EST MON DEC 29 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 455 AM EST MON DEC 29 2014
TODAY AND TONIGHT WILL BE MARKED BY PERSISTENT COOL NW FLOW...WITH
DAYTIME HIGHS FALLING ANOTHER 5F FROM WHAT WAS REALIZED SUNDAY. A
WEAK SFC TROUGH SET UP ACROSS THE CWA WILL CONTINUE TO BE ERODED FOR
ALL BUT FAR E UPPER MI/LAKE SUPERIOR AS VERY STRONG 1060-1062MB
ARCTIC HIGH PRESSURE OVER CENTRAL BRITISH COLUMBIA AND ALBERTA THIS
MORNING.
EXPECT TO SEE SOME TEMPORARY IMPROVING CONDITIONS LES WISE FROM
DAYBREAK THROUGH THE EARLY AFTERNOON HOURS AS THE INITIAL SHORTWAVE
SHIFTS A BIT FARTHER TO OUR N. A SECODARY TROUGH/SHORTWAVE IS
BRINGING HIGH CLOUDS TO THE S TIP OF THE CWA THIS MORNING.
PERSISTENT OFF AND ON LES WILL CONTINUE OUR HIGH POP/LOW QPF
SCENARIO...WITH ONLY A FEW HUNDREDTHS IF THAT EVERY 6 HOURS. 850MB
TEMPS WILL GENERALLY RUN -17 TO -20C THROUGH TONIGHT. BETTER
CONVERGENCE WITH THE LOSS OF DAYTIME HEATING...AND THE APPROACH OF
YET ANOTHER SHORTWAVE WILL HELP BRING A LITTLE BETTER CHANCE OF
ACCUMULATING SNOW TO THE NW WIND SNOWBELTS. A COUPLE OF LOCATIONS IN
ALGER COUNTY COULD GET CLOSE TO ADVISORY SNOW TONIGHT IN CONVERGENT
BANDS OF LES SET UP IN ONE PLACE LONG ENOUGH. OTHERWISE COUNTY
AVERAGE IS RIGHT AROUND 3IN. SIMILAR TO THIS MORNING...CLOUD COVER
WILL MAKE ALL THE DIFFERENCE IN HOW COLD IT WILL GET TONIGHT. EXPECT
INTERIOR W HALF TO FALL INTO THE SINGLE DIGITS BELOW ZERO AGAIN.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 603 AM EST MON DEC 29 2014
WATER VAPOR LOOP AND RUC ANALYSIS SHOWS STRONGLY AMPLIFIED PATTERN
TAKING SHAPE ACROSS NAMERICA WITH RIDGE OVER THE ERN PACIFIC INTO
WRN CANADA/ALASKA AND A BROAD DOWNSTREAM TROF OVER MUCH OF CENTRAL
AND ERN CANADA INTO THE ERN 2/3RDS OF THE CONUS. MODELS INDICATE
THAT THIS PATTERN WILL HOLD AT LEAST INTO MID WEEK ALLOWING FOR THE
BUILDUP AND EXPANSION OF ARCTIC AIR ACROSS CANADA THAT WILL SPILL S
INTO THE CONUS...SIMILAR TO THE PATTERN OBSERVED MOST OF LAST WINTER
AND LAST MONTH. THIS PATTERN WILL RESULT IN MUCH BELOW NORMAL TEMPS
OVER THE NEXT SEVERAL DAYS AND PERSISTENT LAKE EFFECT SNOW FOR THE
NW TO W WIND SNOW BELTS DOWNWIND OF LAKE SUPERIOR. MODELS DIFFER
WITH HANDLING OF CUT OFF LOW WHICH DEVELOPS OVER THE SW CONUS TOWARD
THE MIDDLE OF THE WEEK. BOTH THE ECMWF AND GEM-NH SHOW THE REMNANTS
OF THIS LOW EJECTING DUE E BY NEXT WEEKEND IN SRN BRANCH AND NOT
REALLY IMPACTING THE GREAT LAKES REGION. THE GFS MEANWHILE HAS THE
REMNANTS OF THE LOW EJECTING NE AND PHASING WITH NRN BRANCH AS IT
DEVELOPS A RAPIDLY DEEPENING STORM SYSTEM OVER THE CENTRAL/LOWER
GREAT LAKES BY NEXT SUNDAY. IT WILL BE WORTH MONITORING MODEL TRENDS
WITH THIS SYSTEM AS ANY TREND TOWARD THE 00Z GFS SOLN WOULD SIGNAL
PERHAPS A MUCH MORE SIGNIFICANT IMPACT ON OUR WEATHER FOR NEXT
WEEKEND.
BEGINNING TUE AND TUE NIGHT...THE COLDEST AIR WITH THE INITIAL SURGE
OF ARCTIC AIR WILL SETTLE OVER THE AREA LATE TUE/TUE NIGHT WHEN
850MB TEMPS BOTTOM OUT AROUND -23C. THIS WILL RESULT IN TUE LIKELY
BEING THE COLDEST DAY THIS WEEK FOR MOST AREAS. MAX TEMPS IN GENERAL
WILL RANGE FROM NEAR ZERO FAR WEST TO THE LOW TO MID TEENS EAST.
SUBZERO MIN TEMPS WILL BE THE RULE TUE NIGHT IN THE INTERIOR AWAY
FROM LAKE EFFECT CLOUDS/SNOW WITH TEMPS IN THE INTERIOR W HALF
SLIPPING TO -10F OR COLDER. WINDS BACKING MORE WESTERLY WILL RESULT
IN LESS LAKE EFFECT CLOUDS/SHSN COVERAGE OVER UPPER MI. COMBINED
WITH SOME INCREASE IN WINDS...WIND CHILLS WILL DROP INTO THE -15 TO
-30F RANGE TUE NIGHT INTO WED MORNING. WITH SUCH COLD AIR...NUMEROUS
SNOW SHOWERS WILL CONTINUE IN THE SNOW BELTS FAVORED BY NW TO W
WINDS. NAM/GFS FCST SOUNDINGS SHOW INVERSIONS AT 4-5KFT...SO EXPECT
LES OVERALL TO BE ON THE LIGHT SIDE (GENERALLY 1-4IN/12HRS).
HOWEVER...THERE COULD BE SOME LOCALLY HIGHER AMOUNTS EAST (PERHAPS
ADVISORY LVL) WHERE FETCH ACROSS THE LAKE IS MAXIMIZED..ALLOWING FOR
MORE LAKE MODERATION AND BETTER POSITIONING OF DGZ WITHIN
CONVECTIVE LAYER. SHORTWAVE TROF SWINGING ACROSS THE AREA ON TUE
WILL HAVE SOME IMPACT ON INCREASING MOISTURE DEPTH/RAISING INVERSION
HEIGHTS MAINLY TUE AFTERNOON WHICH COULD RESULT IN A SPIKE IN
LES COVERAGE/INTENSITY FOR A TIME. SO...DAYLIGHT HRS ON TUE PROBABLY
OFFER THE BEST POTENTIAL FOR LES TO PRODUCE ADVY LEVEL ACCUMULATIONS
IN THE SNOW BELTS FAVORED BY NW WINDS.
ON NEW YEARS EVE DAY...LOW-LEVEL WINDS WILL BACK TO THE WSW OR EVEN
SW IN RESPONSE TO THE NEXT SHORTWAVE TROF SWINGING SE THRU MANITOBA
INTO NRN ONTARIO. THIS WILL CAUSE LES TO SHIFT OFFSHORE OF UPPER MI.
HOWEVER...UP AT 850MB...WINDS REMAIN OUT OF THE W. SO...LES WILL
LIKELY CONTINUE TO AFFECT THE KEWEENAW PENINSULA. TIGHTENING PRES
GRADIENT BTWN HIGH PRES OVER THE CNTRL/SRN PLAINS AND LOW PRES OVER
HUDSON BAY WILL RESULT IN INCREASING SFC WINDS...ESPECIALLY OVER THE
EXPOSED KEWEENAW WHERE 950MB WINDS ARE FCST AT 35-40KT. WOULD NOT BE
SURPRISED TO SEE BLIZZARD TO NEAR BLIZZARD CONDITIONS MET OVER
KEWEENAW IF LES COVERAGE REMAINS NUMEROUS OR GREATER...WHICH NAM
SNDGS SUGGEST A GOOD POTENTIAL FOR LES ENHANCEMENT WITH DEEPENING
MOISTURE PROFILE AND DEEP CONVECTION LAYER TROUGH DGZ...ESPECIALLY
LATE WED AFTERNOON INTO NEW YEARS EVE NIGHT. WILL HIGHLIGHT THIS
POTENTIAL IN HWO.
NEXT ARCTIC COLD FRONT ASSOCIATED WITH MANITOBA SHORTWAVE WILL
SWING ACROSS THE AREA EARLY ON NEW YEARS DAY...ENHANCING LES FOR A
TIME IN NW LAKE SUPERIOR SNOWBELTS AND PROBABLY BRINGING ISOLD/SCT
-SHSN TO THE REMAINDER OF THE AREA.
LES WILL CONTINUE ON INTO FRI UNDER COLD AIR MASS...BUT THERE IS
STILL DECENT MODEL AGREEMENT THAT WINDS WILL BACK FRI AS HIGH PRES
RIDGE SLIPS E OF THE AREA AND PRES FALLS SPREAD OUT OVER THE PLAINS.
THE BACKING WINDS AND RESULTING DEVELOPING WAA/ISENTROPIC ASCENT
REGIME WILL ALLOW FOR MORE WIDESPREAD SNOW TO DEVELOP OVER THE NRN
PLAINS AND THEN SPREAD E INTO THE UPPER LAKES.
ON INTO SAT/SUN...MUCH WILL DEPEND ON EVOLUTION OF THE CLOSED LOW
THAT WILL BE OVER THE SW STATES MIDWEEK AS STATED EARLIER IN
DISCUSSION. 00Z GFS SOLN OF DEVELOPING MORE PHASED DEEP STORM SYSTEM
OVER THE CENTRAL GREAT LAKES BY NEXT WEEKEND APPEARS TO BE SOMEWHAT
OF AN OUTLIER BASED ON PREVIOUS GFS RUNS AND THE REST OF THE MODEL
GUIDANCE. I AM MORE INCLINED TO LEAN TOWARD BLEND OF MORE CONSISTENT
00Z ECMWF AND GEM-NH SOLN WHICH KEEPS REMNANTS OF CLOSED LOW MUCH
FARTHER SOUTH. THIS SOLN WOULD SHOW NRN BRANCH REMAINING DOMINANT
OVER UPPER LAKES WITH A RETURN TO COLDER AIR (NEAR -20C AT 850 MB)
FOR NEXT WEEKEND BEHIND FRI/S SYSTEM ALLOWING FOR MORE PERIODS OF
LES FOR THE NW SNOWBELTS ALONG LAKE SUPERIOR. LOOKS LIKE NRN BRANCH
WILL REMAIN ACTIVE INTO EARLY NEXT WEEK AS WELL BRINGING PERIODIC
CLIPPER SYSTEMS THROUGH AREA REINFORCING ARCTIC AIRMASS IN
PLACE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 103 PM EST MON DEC 29 2014
EXPECT MAINLY MVFR CONDITIONS AT IWD/CMX THROUGH THE PERIOD...WITH
SLIGHTLY BETTER CONDITIONS AT SAW.
DESPITE A RIDGE OF STRONG HIGH PRESSURE WORKING IN FROM SW
CANADA...COLD AIR ON NORTHWEST WINDS OVER THE RELATIVELY WARM LAKE
SUPERIOR WATERS WILL KEEP LES GOING AT IWD AND CMX. ALTHOUGH THIS
WIND DIRECTION IS NOT THE BEST FOR SAW TO GET SNOW...OFF AND ON
LIGHT SNOW SHOWERS OR FLURRIES ARE POSSIBLE. EXPECT DAYTIME HEATING TO
HELP DISRUPT SOME OF THE STRONGER BANDS TODAY...BEFORE ANOTHER UPPER
LEVEL DISTURBANCE HELPS BOOST THE POTENTIAL FOR LAKE EFFECT SNOW
SHOWERS AT CMX ONCE AGAIN. AT THAT POINT WINDS OVER N WI AND FAR W
UPPER MI SHOULD BECOME MORE WRLY...LIMITING POTENTIAL FOR MUCH MORE
THAN FLURRIES AT IWD OVERNIGHT.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 455 AM EST MON DEC 29 2014
LOOK FOR A BETTER CHANCE OF FREEZING SPRAY AND STRONG WINDS TUESDAY
NIGHT THROUGH THURSDAY MORNING.
THE OVERALL PATTERN LOOKS LIKE THIS...A RIDGE ACROSS THE UPPER GREAT
LAKES WILL BUILD TUESDAY...AS VERY STRONG ARCTIC HIGH PRESSURE
INITIALLY AT 31.3 INCHES OVER SW CANADA SINKS ACROSS MONTANA. LOOK
FOR THE RIDGE OVER LAKE SUPERIOR TO SINK SOUTH TUESDAY NIGHT. THIS
WILL BE AS A HUDSON BAY LOW SWINGS A TROUGH ACROSS LAKE SUPERIOR.
THE LOW WILL DEEPEN OVER S HUDSON BAY WEDNESDAY NIGHT AS IT BRINGS A
REINFORCING TROUGH ACROSS LAKE SUPERIOR. W GALES OF 35-40KTS ARE
STILL ANTICIPATED /ALONG WITH THE POTENTIAL FOR HEAVY FREEZING
SPRAY/ LATE TUESDAY NIGHT THROUGH THURSDAY MORNING AS THE PRESSURE
GRADIENT TIGHTENS BETWEEN THE EXITING HIGH TO THE S AND STRONG LOW
TO THE N. LOOK FOR THE LOW TO SHIFT ACROSS N QUEBEC AND WEAKEN
SIGNIFICANTLY THURSDAY NIGHT. HIGH PRESSURE WILL THEN BUILD SE
ACROSS SASKATCHEWAN AND S MANITOBA ON THURSDAY AND FRIDAY AS A RIDGE
TRACKS ACROSS THE UPPER GREAT LAKES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING FROM 1 PM EST /NOON CST/ TUESDAY TO
1 PM EST /NOON CST/ THURSDAY FOR LSZ240>245-248>251-263-
265>267.
HEAVY FREEZING SPRAY WARNING FROM 7 PM EST /6 PM CST/ TUESDAY TO
7 AM EST /6 AM CST/ THURSDAY FOR LSZ162.
HEAVY FREEZING SPRAY WARNING FROM 1 AM TUESDAY TO 1 PM EST
THURSDAY FOR LSZ264.
HEAVY FREEZING SPRAY WARNING FROM 1 AM WEDNESDAY TO 1 PM EST
THURSDAY FOR LSZ246-247.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KF
LONG TERM...VOSS
AVIATION...JLB
MARINE...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
710 AM EST MON DEC 29 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 455 AM EST MON DEC 29 2014
TODAY AND TONIGHT WILL BE MARKED BY PERSISTENT COOL NW FLOW...WITH
DAYTIME HIGHS FALLING ANOTHER 5F FROM WHAT WAS REALIZED SUNDAY. A
WEAK SFC TROUGH SET UP ACROSS THE CWA WILL CONTINUE TO BE ERODED FOR
ALL BUT FAR E UPPER MI/LAKE SUPERIOR AS VERY STRONG 1060-1062MB
ARCTIC HIGH PRESSURE OVER CENTRAL BRITISH COLUMBIA AND ALBERTA THIS
MORNING.
EXPECT TO SEE SOME TEMPORARY IMPROVING CONDITIONS LES WISE FROM
DAYBREAK THROUGH THE EARLY AFTERNOON HOURS AS THE INITIAL SHORTWAVE
SHIFTS A BIT FARTHER TO OUR N. A SECODARY TROUGH/SHORTWAVE IS
BRINGING HIGH CLOUDS TO THE S TIP OF THE CWA THIS MORNING.
PERSISTENT OFF AND ON LES WILL CONTINUE OUR HIGH POP/LOW QPF
SCENARIO...WITH ONLY A FEW HUNDREDTHS IF THAT EVERY 6 HOURS. 850MB
TEMPS WILL GENERALLY RUN -17 TO -20C THROUGH TONIGHT. BETTER
CONVERGENCE WITH THE LOSS OF DAYTIME HEATING...AND THE APPROACH OF
YET ANOTHER SHORTWAVE WILL HELP BRING A LITTLE BETTER CHANCE OF
ACCUMULATING SNOW TO THE NW WIND SNOWBELTS. A COUPLE OF LOCATIONS IN
ALGER COUNTY COULD GET CLOSE TO ADVISORY SNOW TONIGHT IN CONVERGENT
BANDS OF LES SET UP IN ONE PLACE LONG ENOUGH. OTHERWISE COUNTY
AVERAGE IS RIGHT AROUND 3IN. SIMILAR TO THIS MORNING...CLOUD COVER
WILL MAKE ALL THE DIFFERENCE IN HOW COLD IT WILL GET TONIGHT. EXPECT
INTERIOR W HALF TO FALL INTO THE SINGLE DIGITS BELOW ZERO AGAIN.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 603 AM EST MON DEC 29 2014
WATER VAPOR LOOP AND RUC ANALYSIS SHOWS STRONGLY AMPLIFIED PATTERN
TAKING SHAPE ACROSS NAMERICA WITH RIDGE OVER THE ERN PACIFIC INTO
WRN CANADA/ALASKA AND A BROAD DOWNSTREAM TROF OVER MUCH OF CENTRAL
AND ERN CANADA INTO THE ERN 2/3RDS OF THE CONUS. MODELS INDICATE
THAT THIS PATTERN WILL HOLD AT LEAST INTO MID WEEK ALLOWING FOR THE
BUILDUP AND EXPANSION OF ARCTIC AIR ACROSS CANADA THAT WILL SPILL S
INTO THE CONUS...SIMILAR TO THE PATTERN OBSERVED MOST OF LAST WINTER
AND LAST MONTH. THIS PATTERN WILL RESULT IN MUCH BELOW NORMAL TEMPS
OVER THE NEXT SEVERAL DAYS AND PERSISTENT LAKE EFFECT SNOW FOR THE
NW TO W WIND SNOW BELTS DOWNWIND OF LAKE SUPERIOR. MODELS DIFFER
WITH HANDLING OF CUT OFF LOW WHICH DEVELOPS OVER THE SW CONUS TOWARD
THE MIDDLE OF THE WEEK. BOTH THE ECMWF AND GEM-NH SHOW THE REMNANTS
OF THIS LOW EJECTING DUE E BY NEXT WEEKEND IN SRN BRANCH AND NOT
REALLY IMPACTING THE GREAT LAKES REGION. THE GFS MEANWHILE HAS THE
REMNANTS OF THE LOW EJECTING NE AND PHASING WITH NRN BRANCH AS IT
DEVELOPS A RAPIDLY DEEPENING STORM SYSTEM OVER THE CENTRAL/LOWER
GREAT LAKES BY NEXT SUNDAY. IT WILL BE WORTH MONITORING MODEL TRENDS
WITH THIS SYSTEM AS ANY TREND TOWARD THE 00Z GFS SOLN WOULD SIGNAL
PERHAPS A MUCH MORE SIGNIFICANT IMPACT ON OUR WEATHER FOR NEXT
WEEKEND.
BEGINNING TUE AND TUE NIGHT...THE COLDEST AIR WITH THE INITIAL SURGE
OF ARCTIC AIR WILL SETTLE OVER THE AREA LATE TUE/TUE NIGHT WHEN
850MB TEMPS BOTTOM OUT AROUND -23C. THIS WILL RESULT IN TUE LIKELY
BEING THE COLDEST DAY THIS WEEK FOR MOST AREAS. MAX TEMPS IN GENERAL
WILL RANGE FROM NEAR ZERO FAR WEST TO THE LOW TO MID TEENS EAST.
SUBZERO MIN TEMPS WILL BE THE RULE TUE NIGHT IN THE INTERIOR AWAY
FROM LAKE EFFECT CLOUDS/SNOW WITH TEMPS IN THE INTERIOR W HALF
SLIPPING TO -10F OR COLDER. WINDS BACKING MORE WESTERLY WILL RESULT
IN LESS LAKE EFFECT CLOUDS/SHSN COVERAGE OVER UPPER MI. COMBINED
WITH SOME INCREASE IN WINDS...WIND CHILLS WILL DROP INTO THE -15 TO
-30F RANGE TUE NIGHT INTO WED MORNING. WITH SUCH COLD AIR...NUMEROUS
SNOW SHOWERS WILL CONTINUE IN THE SNOW BELTS FAVORED BY NW TO W
WINDS. NAM/GFS FCST SOUNDINGS SHOW INVERSIONS AT 4-5KFT...SO EXPECT
LES OVERALL TO BE ON THE LIGHT SIDE (GENERALLY 1-4IN/12HRS).
HOWEVER...THERE COULD BE SOME LOCALLY HIGHER AMOUNTS EAST (PERHAPS
ADVISORY LVL) WHERE FETCH ACROSS THE LAKE IS MAXIMIZED..ALLOWING FOR
MORE LAKE MODERATION AND BETTER POSITIONING OF DGZ WITHIN
CONVECTIVE LAYER. SHORTWAVE TROF SWINGING ACROSS THE AREA ON TUE
WILL HAVE SOME IMPACT ON INCREASING MOISTURE DEPTH/RAISING INVERSION
HEIGHTS MAINLY TUE AFTERNOON WHICH COULD RESULT IN A SPIKE IN
LES COVERAGE/INTENSITY FOR A TIME. SO...DAYLIGHT HRS ON TUE PROBABLY
OFFER THE BEST POTENTIAL FOR LES TO PRODUCE ADVY LEVEL ACCUMULATIONS
IN THE SNOW BELTS FAVORED BY NW WINDS.
ON NEW YEARS EVE DAY...LOW-LEVEL WINDS WILL BACK TO THE WSW OR EVEN
SW IN RESPONSE TO THE NEXT SHORTWAVE TROF SWINGING SE THRU MANITOBA
INTO NRN ONTARIO. THIS WILL CAUSE LES TO SHIFT OFFSHORE OF UPPER MI.
HOWEVER...UP AT 850MB...WINDS REMAIN OUT OF THE W. SO...LES WILL
LIKELY CONTINUE TO AFFECT THE KEWEENAW PENINSULA. TIGHTENING PRES
GRADIENT BTWN HIGH PRES OVER THE CNTRL/SRN PLAINS AND LOW PRES OVER
HUDSON BAY WILL RESULT IN INCREASING SFC WINDS...ESPECIALLY OVER THE
EXPOSED KEWEENAW WHERE 950MB WINDS ARE FCST AT 35-40KT. WOULD NOT BE
SURPRISED TO SEE BLIZZARD TO NEAR BLIZZARD CONDITIONS MET OVER
KEWEENAW IF LES COVERAGE REMAINS NUMEROUS OR GREATER...WHICH NAM
SNDGS SUGGEST A GOOD POTENTIAL FOR LES ENHANCEMENT WITH DEEPENING
MOISTURE PROFILE AND DEEP CONVECTION LAYER TROUGH DGZ...ESPECIALLY
LATE WED AFTERNOON INTO NEW YEARS EVE NIGHT. WILL HIGHLIGHT THIS
POTENTIAL IN HWO.
NEXT ARCTIC COLD FRONT ASSOCIATED WITH MANITOBA SHORTWAVE WILL
SWING ACROSS THE AREA EARLY ON NEW YEARS DAY...ENHANCING LES FOR A
TIME IN NW LAKE SUPERIOR SNOWBELTS AND PROBABLY BRINGING ISOLD/SCT
-SHSN TO THE REMAINDER OF THE AREA.
LES WILL CONTINUE ON INTO FRI UNDER COLD AIR MASS...BUT THERE IS
STILL DECENT MODEL AGREEMENT THAT WINDS WILL BACK FRI AS HIGH PRES
RIDGE SLIPS E OF THE AREA AND PRES FALLS SPREAD OUT OVER THE PLAINS.
THE BACKING WINDS AND RESULTING DEVELOPING WAA/ISENTROPIC ASCENT
REGIME WILL ALLOW FOR MORE WIDESPREAD SNOW TO DEVELOP OVER THE NRN
PLAINS AND THEN SPREAD E INTO THE UPPER LAKES.
ON INTO SAT/SUN...MUCH WILL DEPEND ON EVOLUTION OF THE CLOSED LOW
THAT WILL BE OVER THE SW STATES MIDWEEK AS STATED EARLIER IN
DISCUSSION. 00Z GFS SOLN OF DEVELOPING MORE PHASED DEEP STORM SYSTEM
OVER THE CENTRAL GREAT LAKES BY NEXT WEEKEND APPEARS TO BE SOMEWHAT
OF AN OUTLIER BASED ON PREVIOUS GFS RUNS AND THE REST OF THE MODEL
GUIDANCE. I AM MORE INCLINED TO LEAN TOWARD BLEND OF MORE CONSISTENT
00Z ECMWF AND GEM-NH SOLN WHICH KEEPS REMNANTS OF CLOSED LOW MUCH
FARTHER SOUTH. THIS SOLN WOULD SHOW NRN BRANCH REMAINING DOMINANT
OVER UPPER LAKES WITH A RETURN TO COLDER AIR (NEAR -20C AT 850 MB)
FOR NEXT WEEKEND BEHIND FRI/S SYSTEM ALLOWING FOR MORE PERIODS OF
LES FOR THE NW SNOWBELTS ALONG LAKE SUPERIOR. LOOKS LIKE NRN BRANCH
WILL REMAIN ACTIVE INTO EARLY NEXT WEEK AS WELL BRINGING PERIODIC
CLIPPER SYSTEMS THROUGH AREA REINFORCING ARCTIC AIRMASS IN
PLACE.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 708 AM EST MON DEC 29 2014
EXPECT MAINLY MVFR CEILINGS/VIS THROUGH THE PERIOD...WITH SLIGHTLY
BETTER CONDITIONS AT SAW AND IWD FROM TIME TO TIME...AND SLIGHTLY
WORST CONDITIONS CONDITIONS AT CMX.
DESPITE A RIDGE OF STRONG HIGH PRESSURE WORKING IN FROM SW
CANADA...PERSISTENT COOL NW WINDS OVER THE RELATIVELY WARM LAKE
SUPERIOR WATERS IS KEEPING LAKE EFFECT SNOW SHOWERS IN PLACE OVER
IWD AND CMX. ALTHOUGH THIS WIND DIRECTION IS NOT THE BEST FOR SAW TO
GET SNOW...OFF AND ON LIGHT SNOW SHOWERS OR FLURRIES REMAIN. EXPECT
DAYTIME HEATING TO HELP DISRUPT SOME OF THE STRONGER BANDS
TODAY...BEFORE ANOTHER UPPER LEVEL DISTURBANCE HELPS BOOST THE
POTENTIAL FOR LAKE EFFECT SNOW SHOWERS AT CMX ONCE AGAIN. AT THAT
POINT WINDS OVER N WI AND FAR W UPPER MI SHOULD BECOME MORE DIRECTLY
OUT OF THE W...SHUTTING OFF THE POTENTIAL FOR MUCH MORE THAN
FLURRIES AT IWD OVERNIGHT.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 455 AM EST MON DEC 29 2014
LOOK FOR A BETTER CHANCE OF FREEZING SPRAY AND STRONG WINDS TUESDAY
NIGHT THROUGH THURSDAY MORNING.
THE OVERALL PATTERN LOOKS LIKE THIS...A RIDGE ACROSS THE UPPER GREAT
LAKES WILL BUILD TUESDAY...AS VERY STRONG ARCTIC HIGH PRESSURE
INITIALLY AT 31.3 INCHES OVER SW CANADA SINKS ACROSS MONTANA. LOOK
FOR THE RIDGE OVER LAKE SUPERIOR TO SINK SOUTH TUESDAY NIGHT. THIS
WILL BE AS A HUDSON BAY LOW SWINGS A TROUGH ACROSS LAKE SUPERIOR.
THE LOW WILL DEEPEN OVER S HUDSON BAY WEDNESDAY NIGHT AS IT BRINGS A
REINFORCING TROUGH ACROSS LAKE SUPERIOR. W GALES OF 35-40KTS ARE
STILL ANTICIPATED /ALONG WITH THE POTENTIAL FOR HEAVY FREEZING
SPRAY/ LATE TUESDAY NIGHT THROUGH THURSDAY MORNING AS THE PRESSURE
GRADIENT TIGHTENS BETWEEN THE EXITING HIGH TO THE S AND STRONG LOW
TO THE N. LOOK FOR THE LOW TO SHIFT ACROSS N QUEBEC AND WEAKEN
SIGNIFICANTLY THURSDAY NIGHT. HIGH PRESSURE WILL THEN BUILD SE
ACROSS SASKATCHEWAN AND S MANITOBA ON THURSDAY AND FRIDAY AS A RIDGE
TRACKS ACROSS THE UPPER GREAT LAKES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KF
LONG TERM...VOSS
AVIATION...KF
MARINE...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
603 AM EST MON DEC 29 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 455 AM EST MON DEC 29 2014
TODAY AND TONIGHT WILL BE MARKED BY PERSISTENT COOL NW FLOW...WITH
DAYTIME HIGHS FALLING ANOTHER 5F FROM WHAT WAS REALIZED SUNDAY. A
WEAK SFC TROUGH SET UP ACROSS THE CWA WILL CONTINUE TO BE ERODED FOR
ALL BUT FAR E UPPER MI/LAKE SUPERIOR AS VERY STRONG 1060-1062MB
ARCTIC HIGH PRESSURE OVER CENTRAL BRITISH COLUMBIA AND ALBERTA THIS
MORNING.
EXPECT TO SEE SOME TEMPORARY IMPROVING CONDITIONS LES WISE FROM
DAYBREAK THROUGH THE EARLY AFTERNOON HOURS AS THE INITIAL SHORTWAVE
SHIFTS A BIT FARTHER TO OUR N. A SECODARY TROUGH/SHORTWAVE IS
BRINGING HIGH CLOUDS TO THE S TIP OF THE CWA THIS MORNING.
PERSISTENT OFF AND ON LES WILL CONTINUE OUR HIGH POP/LOW QPF
SCENARIO...WITH ONLY A FEW HUNDREDTHS IF THAT EVERY 6 HOURS. 850MB
TEMPS WILL GENERALLY RUN -17 TO -20C THROUGH TONIGHT. BETTER
CONVERGENCE WITH THE LOSS OF DAYTIME HEATING...AND THE APPROACH OF
YET ANOTHER SHORTWAVE WILL HELP BRING A LITTLE BETTER CHANCE OF
ACCUMULATING SNOW TO THE NW WIND SNOWBELTS. A COUPLE OF LOCATIONS IN
ALGER COUNTY COULD GET CLOSE TO ADVISORY SNOW TONIGHT IN CONVERGENT
BANDS OF LES SET UP IN ONE PLACE LONG ENOUGH. OTHERWISE COUNTY
AVERAGE IS RIGHT AROUND 3IN. SIMILAR TO THIS MORNING...CLOUD COVER
WILL MAKE ALL THE DIFFERENCE IN HOW COLD IT WILL GET TONIGHT. EXPECT
INTERIOR W HALF TO FALL INTO THE SINGLE DIGITS BELOW ZERO AGAIN.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 603 AM EST MON DEC 29 2014
WATER VAPOR LOOP AND RUC ANALYSIS SHOWS STRONGLY AMPLIFIED PATTERN
TAKING SHAPE ACROSS NAMERICA WITH RIDGE OVER THE ERN PACIFIC INTO
WRN CANADA/ALASKA AND A BROAD DOWNSTREAM TROF OVER MUCH OF CENTRAL
AND ERN CANADA INTO THE ERN 2/3RDS OF THE CONUS. MODELS INDICATE
THAT THIS PATTERN WILL HOLD AT LEAST INTO MID WEEK ALLOWING FOR THE
BUILDUP AND EXPANSION OF ARCTIC AIR ACROSS CANADA THAT WILL SPILL S
INTO THE CONUS...SIMILAR TO THE PATTERN OBSERVED MOST OF LAST WINTER
AND LAST MONTH. THIS PATTERN WILL RESULT IN MUCH BELOW NORMAL TEMPS
OVER THE NEXT SEVERAL DAYS AND PERSISTENT LAKE EFFECT SNOW FOR THE
NW TO W WIND SNOW BELTS DOWNWIND OF LAKE SUPERIOR. MODELS DIFFER
WITH HANDLING OF CUT OFF LOW WHICH DEVELOPS OVER THE SW CONUS TOWARD
THE MIDDLE OF THE WEEK. BOTH THE ECMWF AND GEM-NH SHOW THE REMNANTS
OF THIS LOW EJECTING DUE E BY NEXT WEEKEND IN SRN BRANCH AND NOT
REALLY IMPACTING THE GREAT LAKES REGION. THE GFS MEANWHILE HAS THE
REMNANTS OF THE LOW EJECTING NE AND PHASING WITH NRN BRANCH AS IT
DEVELOPS A RAPIDLY DEEPENING STORM SYSTEM OVER THE CENTRAL/LOWER
GREAT LAKES BY NEXT SUNDAY. IT WILL BE WORTH MONITORING MODEL TRENDS
WITH THIS SYSTEM AS ANY TREND TOWARD THE 00Z GFS SOLN WOULD SIGNAL
PERHAPS A MUCH MORE SIGNIFICANT IMPACT ON OUR WEATHER FOR NEXT
WEEKEND.
BEGINNING TUE AND TUE NIGHT...THE COLDEST AIR WITH THE INITIAL SURGE
OF ARCTIC AIR WILL SETTLE OVER THE AREA LATE TUE/TUE NIGHT WHEN
850MB TEMPS BOTTOM OUT AROUND -23C. THIS WILL RESULT IN TUE LIKELY
BEING THE COLDEST DAY THIS WEEK FOR MOST AREAS. MAX TEMPS IN GENERAL
WILL RANGE FROM NEAR ZERO FAR WEST TO THE LOW TO MID TEENS EAST.
SUBZERO MIN TEMPS WILL BE THE RULE TUE NIGHT IN THE INTERIOR AWAY
FROM LAKE EFFECT CLOUDS/SNOW WITH TEMPS IN THE INTERIOR W HALF
SLIPPING TO -10F OR COLDER. WINDS BACKING MORE WESTERLY WILL RESULT
IN LESS LAKE EFFECT CLOUDS/SHSN COVERAGE OVER UPPER MI. COMBINED
WITH SOME INCREASE IN WINDS...WIND CHILLS WILL DROP INTO THE -15 TO
-30F RANGE TUE NIGHT INTO WED MORNING. WITH SUCH COLD AIR...NUMEROUS
SNOW SHOWERS WILL CONTINUE IN THE SNOW BELTS FAVORED BY NW TO W
WINDS. NAM/GFS FCST SOUNDINGS SHOW INVERSIONS AT 4-5KFT...SO EXPECT
LES OVERALL TO BE ON THE LIGHT SIDE (GENERALLY 1-4IN/12HRS).
HOWEVER...THERE COULD BE SOME LOCALLY HIGHER AMOUNTS EAST (PERHAPS
ADVISORY LVL) WHERE FETCH ACROSS THE LAKE IS MAXIMIZED..ALLOWING FOR
MORE LAKE MODERATION AND BETTER POSITIONING OF DGZ WITHIN
CONVECTIVE LAYER. SHORTWAVE TROF SWINGING ACROSS THE AREA ON TUE
WILL HAVE SOME IMPACT ON INCREASING MOISTURE DEPTH/RAISING INVERSION
HEIGHTS MAINLY TUE AFTERNOON WHICH COULD RESULT IN A SPIKE IN
LES COVERAGE/INTENSITY FOR A TIME. SO...DAYLIGHT HRS ON TUE PROBABLY
OFFER THE BEST POTENTIAL FOR LES TO PRODUCE ADVY LEVEL ACCUMULATIONS
IN THE SNOW BELTS FAVORED BY NW WINDS.
ON NEW YEARS EVE DAY...LOW-LEVEL WINDS WILL BACK TO THE WSW OR EVEN
SW IN RESPONSE TO THE NEXT SHORTWAVE TROF SWINGING SE THRU MANITOBA
INTO NRN ONTARIO. THIS WILL CAUSE LES TO SHIFT OFFSHORE OF UPPER MI.
HOWEVER...UP AT 850MB...WINDS REMAIN OUT OF THE W. SO...LES WILL
LIKELY CONTINUE TO AFFECT THE KEWEENAW PENINSULA. TIGHTENING PRES
GRADIENT BTWN HIGH PRES OVER THE CNTRL/SRN PLAINS AND LOW PRES OVER
HUDSON BAY WILL RESULT IN INCREASING SFC WINDS...ESPECIALLY OVER THE
EXPOSED KEWEENAW WHERE 950MB WINDS ARE FCST AT 35-40KT. WOULD NOT BE
SURPRISED TO SEE BLIZZARD TO NEAR BLIZZARD CONDITIONS MET OVER
KEWEENAW IF LES COVERAGE REMAINS NUMEROUS OR GREATER...WHICH NAM
SNDGS SUGGEST A GOOD POTENTIAL FOR LES ENHANCEMENT WITH DEEPENING
MOISTURE PROFILE AND DEEP CONVECTION LAYER TROUGH DGZ...ESPECIALLY
LATE WED AFTERNOON INTO NEW YEARS EVE NIGHT. WILL HIGHLIGHT THIS
POTENTIAL IN HWO.
NEXT ARCTIC COLD FRONT ASSOCIATED WITH MANITOBA SHORTWAVE WILL
SWING ACROSS THE AREA EARLY ON NEW YEARS DAY...ENHANCING LES FOR A
TIME IN NW LAKE SUPERIOR SNOWBELTS AND PROBABLY BRINGING ISOLD/SCT
-SHSN TO THE REMAINDER OF THE AREA.
LES WILL CONTINUE ON INTO FRI UNDER COLD AIR MASS...BUT THERE IS
STILL DECENT MODEL AGREEMENT THAT WINDS WILL BACK FRI AS HIGH PRES
RIDGE SLIPS E OF THE AREA AND PRES FALLS SPREAD OUT OVER THE PLAINS.
THE BACKING WINDS AND RESULTING DEVELOPING WAA/ISENTROPIC ASCENT
REGIME WILL ALLOW FOR MORE WIDESPREAD SNOW TO DEVELOP OVER THE NRN
PLAINS AND THEN SPREAD E INTO THE UPPER LAKES.
ON INTO SAT/SUN...MUCH WILL DEPEND ON EVOLUTION OF THE CLOSED LOW
THAT WILL BE OVER THE SW STATES MIDWEEK AS STATED EARLIER IN
DISCUSSION. 00Z GFS SOLN OF DEVELOPING MORE PHASED DEEP STORM SYSTEM
OVER THE CENTRAL GREAT LAKES BY NEXT WEEKEND APPEARS TO BE SOMEWHAT
OF AN OUTLIER BASED ON PREVIOUS GFS RUNS AND THE REST OF THE MODEL
GUIDANCE. I AM MORE INCLINED TO LEAN TOWARD BLEND OF MORE CONSISTENT
00Z ECMWF AND GEM-NH SOLN WHICH KEEPS REMNANTS OF CLOSED LOW MUCH
FARTHER SOUTH. THIS SOLN WOULD SHOW NRN BRANCH REMAINING DOMINANT
OVER UPPER LAKES WITH A RETURN TO COLDER AIR (NEAR -20C AT 850 MB)
FOR NEXT WEEKEND BEHIND FRI/S SYSTEM ALLOWING FOR MORE PERIODS OF
LES FOR THE NW SNOWBELTS ALONG LAKE SUPERIOR. LOOKS LIKE NRN BRANCH
WILL REMAIN ACTIVE INTO EARLY NEXT WEEK AS WELL BRINGING PERIODIC
CLIPPER SYSTEMS THROUGH AREA REINFORCING ARCTIC AIRMASS IN
PLACE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1157 PM EST SUN DEC 28 2014
NORTHWEST FLOW LAKE EFFECT WILL BE THE MAIN ITEM OF CONCERN. WITH A
STRONG INVERSION AROUND 3KFT ABOVE THE SURFACE...DON/T EXPECT THE
SNOW SHOWERS TO BECOME TOO STRONG AND HAVE KEPT VISIBILITIES IN THE
MVFR TO VFR RANGE AT KCMX/KIWD. LOW LEVEL WINDS DO LOOK TO BACK
SLIGHTLY TONIGHT AHEAD OF A WEAK SURFACE TROUGH THAT WILL THEN SHIFT
WINDS BACK TO THE NORTHWEST AROUND DAYBREAK. THUS...HAVE KEPT VSBYS
A LITTLE HIGHER AT KIWD WITH THOSE BACKING WINDS. ONCE THAT WEAK
TROUGH MOVES THROUGH...WOULD THINK THAT LIGHT LAKE EFFECT WOULD MOVE
BACK INTO THE SITE. OTHERWISE...WITH THE UNFAVORABLE WIND DIRECTION
FOR KSAW...VFR WILL CONTINUE THROUGH THE PERIOD.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 455 AM EST MON DEC 29 2014
LOOK FOR A BETTER CHANCE OF FREEZING SPRAY AND STRONG WINDS TUESDAY
NIGHT THROUGH THURSDAY MORNING.
THE OVERALL PATTERN LOOKS LIKE THIS...A RIDGE ACROSS THE UPPER GREAT
LAKES WILL BUILD TUESDAY...AS VERY STRONG ARCTIC HIGH PRESSURE
INITIALLY AT 31.3 INCHES OVER SW CANADA SINKS ACROSS MONTANA. LOOK
FOR THE RIDGE OVER LAKE SUPERIOR TO SINK SOUTH TUESDAY NIGHT. THIS
WILL BE AS A HUDSON BAY LOW SWINGS A TROUGH ACROSS LAKE SUPERIOR.
THE LOW WILL DEEPEN OVER S HUDSON BAY WEDNESDAY NIGHT AS IT BRINGS A
REINFORCING TROUGH ACROSS LAKE SUPERIOR. W GALES OF 35-40KTS ARE
STILL ANTICIPATED /ALONG WITH THE POTENTIAL FOR HEAVY FREEZING
SPRAY/ LATE TUESDAY NIGHT THROUGH THURSDAY MORNING AS THE PRESSURE
GRADIENT TIGHTENS BETWEEN THE EXITING HIGH TO THE S AND STRONG LOW
TO THE N. LOOK FOR THE LOW TO SHIFT ACROSS N QUEBEC AND WEAKEN
SIGNIFICANTLY THURSDAY NIGHT. HIGH PRESSURE WILL THEN BUILD SE
ACROSS SASKATCHEWAN AND S MANITOBA ON THURSDAY AND FRIDAY AS A RIDGE
TRACKS ACROSS THE UPPER GREAT LAKES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KF
LONG TERM...VOSS
AVIATION...07
MARINE...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1157 PM EST SUN DEC 28 2014
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 216 PM EST SUN DEC 28 2014
PERSISTENT LIGHT AND FLUFFY LAKE EFFECT IN THE NORTHWEST WIND SNOW
BELTS WILL BE THE NORM FOR THE SHORT TERM FORECAST.
A SURFACE TROUGH SWEPT SOUTHEAST ACROSS UPPER MICHIGAN THIS
MORNING AND EARLY AFTERNOON AND HAS SWITCHED WINDS TO THE NORTHWEST
AND BROUGHT MUCH COLDER AIR INTO THE AREA. 850MB TEMPS AT THIS TIME
ON THE RAP ANALYSIS ARE -18C OVER WESTERN LAKE SUPERIOR AND WESTERN
UPPER MICHIGAN. THIS COLD AIR...AIDED BY MOISTURE FROM THE SURFACE
TROUGH THAT SWEPT THROUGH THE AREA...LED TO SOME LAKE EFFECT SNOW IN
THE WEST AND NOW NORTHWEST WIND SNOWBELTS THROUGH THE DAY. WHILE
THERE WERE SOME STRONGER SHOWERS THIS MORNING...ASSISTED BY
CONVERGENCE ALONG THE FRONT AND FROM THE SOUTHERN EDGE OF THE
SHORTWAVE MOVING EAST JUST TO THE NORTH OF LAKE SUPERIOR...THEY HAVE
NOW TRANSITIONED TO MORE OF A MULTIBAND LES LOOK ON SATELLITE OVER
WESTERN UPPER MICHIGAN. USING THE EXPERIMENTAL SSEC SATELLITE
DERIVED SNOWFALL RATES...IT APPEARS THAT SOME AREAS ARE SEEING
TRANSIENT BANDS OF 0.5 IN/HR RATES AND THAT SEEMS TO MATCH UP WITH
VISIBILITY REPORTS AT KCMX. WITH THE DEEPER MOISTURE STARTING TO
PULL OUT OF THAT AREA...HAVE ALREADY SEEN SOME WEAKENING OVER
WESTERN LAKE SUPERIOR...HELPED BY INVERSION HEIGHTS FALLING
BEHIND THE TROUGH. THE 12Z KINL SOUNDING HAD INVERSION HEIGHTS
AROUND 900MB OR 3KFT...BUT WITH SOME LAKE MODIFICATION THEY SHOULD
BE IN THE 4-5KFT RANGE. OVER THE EAST...THERE WAS A STRONGER BAND
BETWEEN MUNISING AND MINER/S CASTLE THIS MORNING THAT LIKELY
PRODUCED A COUPLE-FEW INCHES OF SNOW. THIS BAND WAS AIDED BY THE
CONVERGENT FLOW OFF MARQUETTE COUNTY AHEAD OF THE SURFACE TROUGH.
BUT NOW THAT THE TROUGH IS MOVING THROUGH NORTH CENTRAL UPPER
MICHIGAN...THE BAND HAS BECOME MUDDLED. WITH THE LAKE EFFECT
TRANSITIONING TO MULTIBAND OVER THE EASTERN LAKE...ACCUMULATIONS
SHOULD BE LIMITED THE REST OF THE AFTERNOON.
OVERALL...LITTLE CHANGE IN THE OVERALL CONDITIONS OVER THE CWA
DURING THE SHORT TERM PERIOD...AS HIGH PRESSURE RIDGE BUILDS OVER
THE AREA FROM A STRONG HIGH IN NORTHWEST CANADA. WITH 875MB TEMPS
FALLING TO -21C...EXPECT HIGH POP LOW QPF LAKE EFFECT TO CONTINUE
THROUGH THE PERIOD IN THE NORTHWEST WIND SNOWBELTS. THERE DOES
APPEAR TO BE A BRIEF PERIOD OF BACKING WINDS OVERNIGHT AS A WEAK
TROUGH MOVES THROUGH TONIGHT BEFORE SETTLING BACK TO NORTHWEST WINDS
FOR MONDAY. THIS WEAK TROUGH WILL BRING A LITTLE MORE LOW LEVEL
MOISTURE TO THE AREA FOR THE LAKE EFFECT TO WORK WITH LATE TONIGHT
INTO MONDAY MORNING (SEEN ON THE 12Z CWPL SOUNDING). BUT THE RIDGE
MOVING OVER THE AREA WILL KEEP THE LOWER INVERSION HEIGHTS IN PLACE
THROUGH THE PERIOD AND KEEP SNOWFALL AMOUNTS IN CHECK. FOR TONIGHT
AND AGAIN ON MONDAY...HAVE THE NORTHWEST WIND SNOW BELTS RECEIVING
1-3 INCHES OF FLUFFY SNOW EVERY 12 HOURS...LARGELY HELPED BY THE
ENTIRE CLOUD BEING WITHIN THE DGZ. WITH THE LONGER FETCH AND IN TURN
LAKE MODIFICATION...HAVE A LITTLE HIGHER AMOUNTS OVER THE EAST BUT
STILL ONLY LOCALIZED 4 INCH AMOUNTS. THERE ARE SOME INDICATIONS OF
LOW LEVEL DRYING LATE TOMORROW AFTERNOON WHICH COULD WEAKEN THE LAKE
EFFECT SOME AND HAVE LOWERED THE POPS A LITTLE TO ACCOUNT FOR THAT.
AS IS NORMALLY THE CASE IN THE LAKE EFFECT REGIMES...LOWS TONIGHT
WILL DEPEND ON CLOUD COVER. WHERE CLEARING IS EXPECTED TO
OCCUR...HAVE LOWS IN THE SINGLE DIGITS ABOVE/BELOW ZERO.
OTHERWISE...UNDER THE CLOUDS WOULD EXPECT TEMPS IN THE UPPER SINGLE
DIGITS OR LOWER TEENS. HIGHS TOMORROW WILL BE CLOSE TO 10 DEGREES
BELOW NORMAL AND IN THE TEENS ABOVE ZERO.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 434 PM EST SUN DEC 28 2014
TODAYS MEDIUM RANGE MODELS STRONGLY SUPPORT LONG TERM FCST PRODUCED
OVER THE LAST 3 DAYS. SO...FCST CHANGES IN THE LONG TERM TODAY WILL
BE MINOR. BIGGEST FCST CHALLENGE WILL OCCUR AT THE END OF THE
WEEK/WEEKEND. MORE ON THAT LATER. THE LONG ADVERTISED SIGNIFICANT
PATTERN CHANGE ACROSS NAMERICA IS NOW WELL UNDERWAY AS A STRONG
RIDGE IS BUILDING N THRU ALASKA. 12Z RAOBS SHOW 12HR 500MB HEIGHT
RISES OF 130-150M IN NRN ALASKA/ADJACENT FAR NW CANADA...AND HEIGHT
ANOMALIES ARE NOW 2 STANDARD DEVIATIONS ABOVE THE LONG TERM LATE DEC
AVG. 500MB HEIGHT ANOMALIES ARE STILL FCST TO PEAK AT 2.5 STANDARD
DEVIATIONS LATER TODAY THRU EARLY WED. OF COURSE...THE DOWNSTREAM
RESPONSE WILL BE A DEVELOPING CNTRL/ERN NAMERICA TROF. THIS
AMPLIFIED PATTERN WILL ALLOW THE BUILDUP AND EXPANSION OF ARCTIC AIR
ACROSS CANADA THAT WILL SPILL S INTO THE CONUS...SIMILAR TO THE
PATTERN OBSERVED MOST OF LAST WINTER AND LAST MONTH. SO...AFTER AN
EXTENDED PERIOD OF MOSTLY ABOVE NORMAL TEMPS OVER THE LAST 3
WEEKS...A BLO NORMAL TEMP REGIME WILL TAKE HOLD ON MON AND CONTINUE
THRU AT LEAST THE NEXT 10 DAYS...THOUGH A DAY OR TWO MAY SEE TEMPS
CLOSE TO NORMAL DURING THAT TIME. THERE ARE INDICATIONS THAT THE
MOST SIGNIFICANT CHILL COULD OCCUR IN THE 7-10 DAY TIME FRAME.
FARTHER OUT TO DAY 16...MAJORITY OF GEM ENSEMBLES STILL INDICATE
DEAMPLIFICATION AND A TREND BACK TOWARD NORMAL TEMPS BY MID JAN.
CFSV2 GOES FURTHER TO BRING A RETURN OF A WARM PATTERN/ABOVE NORMAL
TEMPS FOR MID/LATE JAN. WE`LL SEE. AS FOR PCPN...PCPN THIS WEEK WILL
BE CONFINED ALMOST EXCLUSIVELY TO THE LAKE EFFECT SNOW BELTS NEAR
LAKE SUPERIOR AS COLD NW FLOW PREVAILS. AS HAS BEEN THE CASE THE
LAST FEW DAYS...THERE CONTINUE TO BE INDICATIONS THAT A LOW PRES
SYSTEM COULD TRACK FROM THE SRN PLAINS TO THE GREAT LAKES LATE
WEEK/WEEKEND. WHILE THIS STILL SEEMS LIKE A LOW PROBABILITY BASED ON
ALL AVBL MEDIUM RANGE GUIDANCE (AT LEAST AS FAR AS BRINGING
SIGNIFICANT PCPN INTO UPPER MI)...THERE ARE SUBTLE MULTI-MODEL
TRENDS SUPPORTING AN INCREASED LIKELIHOOD OF AT LEAST WIDESPREAD
-SN...INCLUDING LAKE ENHANCEMENT NEAR LAKE SUPERIOR. LATE
WEEK/WEEKEND WILL CONTINUE TO BE A TIME FRAME TO MONITOR IN THE
COMING DAYS.
BEGINNING MON NIGHT THRU TUE NIGHT...THE COLDEST AIR OF THIS INITIAL
SURGE OF ARCTIC AIR WILL SETTLE OVER THE AREA ON TUE WHEN 850MB
TEMPS BOTTOM OUT AROUND -23C. THIS WILL RESULT IN TUE LIKELY BEING
THE COLDEST DAY THIS WEEK FOR MOST AREAS. MAX TEMPS IN GENERAL WILL
BE IN THE 5 TO 15F RANGE...THOUGH OVER THE FAR W AROUND KIWD...TEMPS
MAY ONLY RISE TO JUST ABOVE 0F. MON NIGHT AND TUE NIGHT...SUBZERO
MIN TEMPS WILL BE THE RULE IN THE INTERIOR AWAY FROM LAKE EFFECT
CLOUDS/SNOW. TUE NIGHT WILL LIKELY BE COLDEST WITH TEMPS IN THE
INTERIOR W HALF SLIPPING TO -10F OR LWR. SUBZERO TEMPS SHOULD COVER
A WIDER AREA ON TUE NIGHT AS WELL SINCE WINDS BACKING MORE WESTERLY
WILL RESULT IN LESS LAKE EFFECT CLOUDS/SHSN COVERAGE OVER UPPER MI.
COMBINED WITH SOME INCREASE IN WINDS...WIND CHILLS WILL DROP INTO
THE -15 TO -25F RANGE TUE NIGHT INTO WED MORNING. WITH SUCH COLD
AIR...NMRS SNOW SHOWERS WILL CONTINUE IN THE SNOW BELTS FAVORED BY
NW TO W WINDS. NAM/GFS FCST SOUNDINGS SHOW INVERSIONS AT 4-5KFT...SO
LES WILL OVERALL BE ON THE LIGHT SIDE (1-4IN/12HRS). HOWEVER...WHERE
FETCH ACROSS THE LAKE IS LONGEST...ALLOWING MOST LAKE MODERATION...
DGZ WILL DOMINATE THE CONVECTIVE LAYER...AND THIS MAY ALLOW FOR SOME
ADVY LEVEL SNOW ACCUMULATIONS...IN PARTICULAR WHERE LONGER FETCH AND
LOCALIZED ENHANCED CONVERGENCE WORK TOGETHER. SIMILAR TO THE LAST
FEW DAYS OF MODEL RUNS...SHORTWAVE TROF SWINGING ACROSS THE AREA ON
TUE WILL HAVE SOME IMPACT ON INCREASING MOISTURE DEPTH/RAISING
INVERSION HEIGHTS (FOR ROUGHLY 6HRS)...RESULTING IN AN INCREASE IN
LES COVERAGE/INTENSITY FOR A TIME. SO...DAYLIGHT HRS ON TUE PROBABLY
OFFER THE BEST POTENTIAL FOR LES TO PRODUCE ADVY LEVEL ACCUMULATIONS
IN THE SNOW BELTS FAVORED BY NW WINDS.
ON NEW YEARS EVE DAY...LOW-LEVEL WINDS WILL BACK TO THE WSW OR EVEN
SW IN RESPONSE TO THE NEXT SHORTWAVE TROF SWINGING SE THRU MANITOBA
INTO NRN ONTARIO. THIS WILL CAUSE LES TO SHIFT OFFSHORE OF UPPER MI.
HOWEVER...UP AT 850MB...WINDS REMAIN OUT OF THE W. SO...LES WILL
LIKELY CONTINUE TO AFFECT THE KEWEENAW PENINSULA. TIGHTENING PRES
GRADIENT BTWN HIGH PRES OVER THE CNTRL/SRN PLAINS AND LOW PRES OVER
HUDSON BAY WILL RESULT IN INCREASING SFC WINDS...ESPECIALLY OVER THE
EXPOSED KEWEENAW WHERE 950MB WINDS ARE FCST AT 35-40KT. BLSN MAY
BECOME AN ISSUE THERE ON NEW YEARS EVE...ESPECIALLY IF SHSN COVERAGE
REMAINS NMRS OR GREATER.
NEXT ARCTIC COLD FRONT ASSOCIATED WITH AFORMENTIONED SHORTWAVE TROF
SWINGING ACROSS NRN ONTARIO WILL THEN SWEEP ACROSS THE AREA EARLY ON
NEW YEARS DAY...ENHANCING LES FOR A TIME AND PROBABLY BRINGING AT
ISOLD/SCT -SHSN TO THE REMAINDER OF THE AREA.
LES WILL CONTINUE ON INTO FRI UNDER COLD AIR MASS...BUT THERE IS
INCREASING MODEL AGREEMENT THAT WINDS WILL BACK FRI AS HIGH PRES
RIDGE SLIPS E OF THE AREA AND PRES FALLS SPREAD OUT OVER THE PLAINS.
THE BACKING WINDS AND RESULTING DEVELOPING WAA/ISENTROPIC ASCENT
REGIME WILL ALLOW FOR A BAND OF -SN TO DEVELOP OVER THE NRN PLAINS
AND THEN STREAK E INTO THE UPPER LAKES...BUT PROBABLY NOT UNTIL FRI
NIGHT.
ON INTO SAT...MUCH WILL DEPEND ON EVOLUTION OF THE CLOSED LOW THAT
WILL BE OVER THE SW STATES MIDWEEK. THE GFS HAS BEEN VERY CONSISTENT
ON THE NW SIDE OF GUIDANCE IN TAKING THAT ENERGY INTO THE GREAT
LAKES REGION. FOR A NUMBER OF RUNS...IT HAS TRACKED A SFC LOW NE...
ROUGHLY ACROSS THE SE HALF OF LWR MI. THE 00Z ECMWF STARTED TO TREND
SLIGHTLY N AND W WITH TRACK...BUT THE 12Z RUN IS MUCH MORE
SUPPRESSED WITH THE LOW...A RESULT OF THE NE PACIFIC RIDGE BEING
LESS PRONOUNCED WHICH LEADS TO FLATTER DOWNSTREAM FLOW. THERE A FEW
MORE GEM ENSEMBLES SIMILAR TO THE GFS TODAY...BUT THEY ARE STILL A
DEFINITE MINORITY. MUCH WILL DEPEND ON THE STRUCTURE/AMPLITUDE OF
THE NE PACIFIC RIDGE...BUT AT THIS POINT...GIVEN TODAYS AND RECENT
DAYS MEDIUM RANGE GUIDANCE...THE PROBABILITY IS STILL VERY LOW FOR
THE SFC LOW TO TRACK FAR ENOUGH N AND W TO BRING SIGNIFICANT PCPN TO
THE FCST AREA. HOWEVER...AIDED BY NRN STREAM ENERGY...THERE SHOULD
BE SOME -SN ACROSS THE FCST AREA ON SAT ALONG WITH THE POTENTIAL FOR
LAKE ENHANCEMENT NEAR LAKE SUPERIOR. ARCTIC AIR WILL FLOW BACK INTO
THE UPPER LAKES ON SUN...RENEWING LES IN AREAS FAVORED BY NW WINDS.
COLDEST AIR OF THE SEASON COULD FOLLOW FOR MON/TUE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1157 PM EST SUN DEC 28 2014
NORTHWEST FLOW LAKE EFFECT WILL BE THE MAIN ITEM OF CONCERN. WITH A
STRONG INVERSION AROUND 3KFT ABOVE THE SURFACE...DON/T EXPECT THE
SNOW SHOWERS TO BECOME TOO STRONG AND HAVE KEPT VISIBILITIES IN THE
MVFR TO VFR RANGE AT KCMX/KIWD. LOW LEVEL WINDS DO LOOK TO BACK
SLIGHTLY TONIGHT AHEAD OF A WEAK SURFACE TROUGH THAT WILL THEN SHIFT
WINDS BACK TO THE NORTHWEST AROUND DAYBREAK. THUS...HAVE KEPT VSBYS
A LITTLE HIGHER AT KIWD WITH THOSE BACKING WINDS. ONCE THAT WEAK
TROUGH MOVES THROUGH...WOULD THINK THAT LIGHT LAKE EFFECT WOULD MOVE
BACK INTO THE SITE. OTHERWISE...WITH THE UNFAVORABLE WIND DIRECTION
FOR KSAW...VFR WILL CONTINUE THROUGH THE PERIOD.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 216 PM EST SUN DEC 28 2014
AS THE SURFACE TROUGH THAT SLID SOUTHEAST ACROSS LAKE SUPERIOR THIS
MORNING CONTINUES SOUTHEAST THROUGH THE LOWER GREAT
LAKES...PERSISTENT NORTHWEST WINDS OF 15-25KTS ARE EXPECTED OVER
THE LAKE THROUGH TUESDAY. THIS IS DUE TO THE AREA BEING BETWEEN A
STRONG HIGH MOVING INTO THE NORTHERN/CENTRAL PLAINS AND A LOW NEAR
HUDSON BAY. A SURFACE TROUGH WILL SWEEP ACROSS LAKE SUPERIOR ON
WEDNESDAY NIGHT AND TIGHTEN THE PRESSURE GRADIENT ACROSS THE LAKE.
THIS IS EXPECTED TO PRODUCE WESTERLY GALES OF 35-40KTS WEDNESDAY
INTO THURSDAY MORNING.
WITH MUCH COLDER TEMPERATURES MOVING OVER LAKE SUPERIOR OVER THE
NEXT SEVERAL DAYS...FREEZING SPRAY IS POSSIBLE FOR MUCH OF THE
PERIOD. WITH THE STRONGER WINDS TUESDAY NIGHT INTO THURSDAY...HEAVY
FREEZING SPRAY IS EXPECTED OVER MUCH OF THE LAKE.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...ROLFSON
AVIATION...07
MARINE...SRF
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1116 AM CST MON DEC 29 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 530 AM CST MON DEC 29 2014
THE SHORT TERM IS A BIT COMPLICATED. A COLD FRONT PASSED SOUTH
ACROSS THE CWA OVERNIGHT AND LIGHT SNOW HAS BROKEN OUT BEHIND IT.
MODELS ARE TRENDING LATER WITH THE BEGINNING OF SNOW. THE NAM AND
WRF...ALONG WITH THE HRRR INDICATE THAT THE SNOW ENTERING FROM THE
NORTH WILL HAVE A TOUGH TIME MAKING IT MUCH FARTHER SOUTH THAN
INTERSTATE 80 THIS AFTERNOON. AS THIS AREA OF SNOW STALLS AND
DISSIPATES...A MID-LEVEL PERTURBATION HEADS IN FROM THE WEST ACROSS
NORTHERN KANSAS ALONG WITH AN UPPER LEVEL JET MAXIMUM WILL HELP GET
SNOW GOING AGAIN...ESPECIALLY IN OUR FAR SOUTHWESTERN CWA. WE COULD
GET CLOSE TO THREE INCHES OF SNOW IN THESE AREAS...CONSIDERING A
GENERAL ENSEMBLE APPROACH TO MODEL QPF...ALONG WITH SNOW/LIQUID
WATER RATIOS 13 TO 1 FOR TONIGHT...WHICH IS FAIRLY TYPICAL. WENT
WITH A WINTER WEATHER ADVISORY IN OUR SOUTHWEST...CONSIDERING NOT
ONLY WE SHOULD JUST MEET SNOWFALL AMOUNT CRITERION...BUT THE
PRESSURE GRADIENT TODAY WILL BRING IN WIND FROM THE NORTH AT AROUND
20 MPH GUSTING TO 30 MPH. NUMERICAL MODELS ARE TRENDING LATER WITH
ENDING TIME...AND HAVE CONTINUED THIS ADVISORY INTO TUESDAY MORNING.
THIS COULD REDUCE VISIBILITY AS WELL. MY SNOW AMOUNTS MATCH UP
FAIRLY WELL WITH THE LATEST WPC GUIDANCE...WITH NEAR ONE INCH IN OUR
EAST TO THE 2 TO 4 INCH RANGE IN OUR WESTERN HALF OF THE CWA.
CONSIDERING THE GENERAL AGREEMENT BETWEEN THE NAM...NMM WRF...AND
SREF ENSEMBLES...I HAVE BUMPED UP CHANCES OF PRECIPITATION/SNOW
CONSIDERABLY...ESPECIALLY IN OUR SOUTHWEST FOR THIS AFTERNOON INTO
TONIGHT...BUT ALSO DELAYING THE ARRIVAL IN OUR SOUTHEAST A BIT
LONGER...CONSIDERING THAT THE NORTHERN BATCH OF SNOW SHOULD LOSE ITS
PUNCH BEFORE LONG. ALSO RAISED HIGH TEMPERATURES IN OUR NORTH
COMPARED TO THE PREVIOUS FORECAST... SINCE TEMPERATURES
ARE CURRENTLY 5 TO 7 DEGREES WARMER THAN THE EARLIER PREDICTED HIGH
FOR TODAY.
CONSIDERING THAT THE WIND SPEEDS WILL BE A BIT ELEVATED...EVEN LATE
TONIGHT...I DO NOT ANTICIPATE THAT LOWS WILL GET QUITE AS COOL AS
EARLIER PREDICTED...IN GENERAL...AND I HAVE BUMPED UP LOWS A COUPLE
OF DEGREES. I AM QUITE SKEPTICAL OF THE MID-LEVEL SKY COVER
ADVERTISED BY MODEL SOUNDINGS. MID-LEVEL SKY COVER IS FORECAST TO
HANG AROUND...DESPITE MUCH MORE DRY AND COLDER ARCTIC AIR IS MOVING
IN. I SUSPECT AT LEAST PARTIAL CLEARING COULD OCCUR IN OUR
NORTH/NORTHEAST BY THE END OF THE NIGHT. WITH THE WIND SPEEDS
ELEVATED...THIS ALONE SHOULD NOT HAVE AS MUCH OF AN EFFECT. HAVING
SAID THIS...WIND SPEEDS SHOULD BE HIGH ENOUGH TO NEED A WIND CHILL
ADVISORY ALONG AND NORTH OF HIGHWAY 6 LATE TONIGHT INTO TUESDAY
MORNING.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 530 AM CST MON DEC 29 2014
THE PRIMARY FORECAST CONCERN WILL CENTER AROUND THE BITTERLY COLD
TEMPERATURES TUESDAY THROUGH WEDNESDAY.
TUESDAY...SEVERAL FORECAST MODELS (00Z GEM...00Z ECMWF...06Z
NAM...AND A FEW WRF RUNS) ARE LINGERING THE LIGHT SNOW ACROSS OUR
SOUTHWESTERN ZONES INTO THE DAYLIGHT HOURS TUESDAY MORNING.
THEREFORE...HAVE INCREASED SNOW CHANCES TUESDAY MORNING ACROSS
SOUTHWESTERN ZONES...SOUTHWEST OF THE TRI-CITIES. SNOW WILL BE IN
THE PROCESS OF ENDING FROM NORTH TO SOUTH TUESDAY MORNING WITH ANY
ADDITIONAL ACCUMULATION AFTER SUNRISE TUESDAY MORNING LIKELY LESS
THAN ONE HALF INCH AND PRIMARILY CONFINED TO COUNTIES CURRENTLY
UNDER THE WINTER WEATHER ADVISORY. THE MORE WIDESPREAD ISSUE ACROSS
OUR FORECAST AREA WILL BE THE COLD AS WIND CHILL VALUES WILL LIKELY
FALL INTO THE -20 TO -30F RANGE ACROSS MOST OF OUR NEBRASKA COUNTIES
EXCEPT FOR THE SOUTHERN MOST TIER OF COUNTIES. OUR WIND CHILL
ADVISORY CRITERIA IS -20 TO -30F AND THEREFORE A WIND ADVISORY IS
NOW IN EFFECT FOR MOST OF OUR NEBRASKA COUNTIES FROM LATE TONIGHT
THROUGH TUESDAY MORNING. A NORTH WIND OF AROUND 15 TO 20 MPH GUSTING
TO AROUND 25 MPH ALONG WITH TUESDAY MORNING LOWS OF 0 TO -7F SHOULD
BE SUFFICIENT TO PUSH OUR WIND CHILLS DOWN INTO ADVISORY CRITERIA.
COLD AIR WILL CONTINUE TO FILTER INTO THE REGION THROUGHOUT THE DAY
MAKING IT HARD FOR TEMPERATURES TO RISE. IN ADDITION...MID TO HIGH
CLOUDS ARE EXPECTED THROUGH MUCH OF THE DAY AND ALONG WITH OUR
CURRENT SNOW COVER WILL ALSO MAKE IT DIFFICULT FOR TEMPERATURES TO
RISE. THEREFORE...WILL CALL FOR HIGHS ONLY IN THE 5 TO 10F RANGE.
TUESDAY NIGHT INTO WEDNESDAY...THE COLDEST NIGHT OF THE WEEK WILL
LIKELY BY TUESDAY NIGHT AS WE SEE CLEARING SKIES AND DECREASING
WINDS...WHICH WILL HELP LOWS FALL INTO THE -1 TO -10F RANGE ACROSS
THE FORECAST AREA. ANOTHER WIND CHILL ADVISORY WILL LIKELY BE NEEDED
FOR TUESDAY NIGHT INTO WEDNESDAY MORNING. ALTHOUGH THE WIND WILL BE
LIGHTER...THE AIR TEMPERATURES WILL BE COLDER SO THAT THE WIND CHILL
VALUES TUESDAY NIGHT/WEDNESDAY MORNING WILL LIKELY BE RATHER
COMPARABLE TO THE WIND CHILL VALUES EXPECTED TONIGHT INTO TUESDAY
MORNING. THE MODERATION IF YOU CAN CALL IT THAT WILL BEGIN DURING
THE DAY ON WEDNESDAY WITH A WEST SOUTHWEST WIND HELPING HIGHS TO
CLIMB BACK INTO THE TEENS.
THURSDAY THROUGH SUNDAY...A CUT OFF UPPER AREA OF LOW PRESSURE OVER
THE DESERT SOUTHWEST ON THURSDAY WILL SLOWLY TRACK ACROSS THE
SOUTHERN PLAINS FRIDAY AND SATURDAY...AND INTO THE MISSISSIPPI
VALLEY BY SUNDAY. MOST FORECAST MODELS KEEP THIS STORM TRACK FAR
ENOUGH SOUTH THAT WE WILL LIKELY BE DRY ACROSS OUR FORECAST AREA.
FOR THE SAKE OF A COUPLE OF OUTLYING MODELS WILL ALLOW THE SLIGHT
CHANCE OF SNOW ACROSS SOUTHEASTERN ZONES ON FRIDAY/FRIDAY NIGHT TO
REMAIN IN THE FORECAST...BUT CONFIDENCE IS LOW IN SEEING MEASURABLE
PRECIPITATION. THERE SHOULD BE SOME ADDITIONAL MODERATION IN
TEMPERATURES THURSDAY THROUGH SATURDAY AHEAD OF THE SOUTHERN STORM
SYSTEM WITH COLDER AIR FILTERING BACK IN BEHIND THE DEPARTING
SOUTHERN STORM SYSTEM ON SUNDAY. OVERALL...IT WILL REMAIN A COLD
PERIOD WITH HIGHS GENERALLY IN THE 20S FOR MOST AREAS...TO MAYBE
LOWER 30S SOUTH.
&&
.AVIATION...(FOR THE 18Z KGRI/KEAR TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1111 AM CST MON DEC 29 2014
THE FIRST ROUND OF LIGHT SNOW WILL PERSIST THRU THE AFTN WHICH IS
ASSOCIATED WITH MID LEVEL FRONTOGENESIS FOLLOWING THE PASSAGE OF A
COLD FRONTAL BOUNDARY. ANOTHER ROUND OF SNOW IS EXPECTED TO
DEVELOP THIS EVENING EVENING AND TONIGHT AHEAD OF A TROUGH MOVING
OUT OF THE ROCKIES. DRIER AIR ADVECTING IN FROM THE NORTH WILL
EVENTUALLY CAUSE SNOW TO END AT THE TERMINALS. WINDS WILL BE
STEADY FROM A NORTHERLY DIRECTION.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO NOON CST TUESDAY
FOR NEZ039>041-046>049-060>064-072>077.
WINTER WEATHER ADVISORY UNTIL 9 AM CST TUESDAY FOR NEZ082-083.
KS...WINTER WEATHER ADVISORY UNTIL 9 AM CST TUESDAY FOR KSZ005-017-
018.
&&
$$
SHORT TERM...HEINLEIN
LONG TERM...WESELY
AVIATION...FAY
AREA FORECAST DISCUSSION
NWS HASTINGS NE
545 AM CST MON DEC 29 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 530 AM CST MON DEC 29 2014
THE SHORT TERM IS A BIT COMPLICATED. A COLD FRONT PASSED SOUTH
ACROSS THE CWA OVERNIGHT AND LIGHT SNOW HAS BROKEN OUT BEHIND IT.
MODELS ARE TRENDING LATER WITH THE BEGINNING OF SNOW. THE NAM AND
WRF...ALONG WITH THE HRRR INDICATE THAT THE SNOW ENTERING FROM THE
NORTH WILL HAVE A TOUGH TIME MAKING IT MUCH FARTHER SOUTH THAN
INTERSTATE 80 THIS AFTERNOON. AS THIS AREA OF SNOW STALLS AND
DISSIPATES...A MID-LEVEL PERTURBATION HEADS IN FROM THE WEST ACROSS
NORTHERN KANSAS ALONG WITH AN UPPER LEVEL JET MAXIMUM WILL HELP GET
SNOW GOING AGAIN...ESPECIALLY IN OUR FAR SOUTHWESTERN CWA. WE COULD
GET CLOSE TO THREE INCHES OF SNOW IN THESE AREAS...CONSIDERING A
GENERAL ENSEMBLE APPROACH TO MODEL QPF...ALONG WITH SNOW/LIQUID
WATER RATIOS 13 TO 1 FOR TONIGHT...WHICH IS FAIRLY TYPICAL. WENT
WITH A WINTER WEATHER ADVISORY IN OUR SOUTHWEST...CONSIDERING NOT
ONLY WE SHOULD JUST MEET SNOWFALL AMOUNT CRITERION...BUT THE
PRESSURE GRADIENT TODAY WILL BRING IN WIND FROM THE NORTH AT AROUND
20 MPH GUSTING TO 30 MPH. NUMERICAL MODELS ARE TRENDING LATER WITH
ENDING TIME...AND HAVE CONTINUED THIS ADVISORY INTO TUESDAY MORNING.
THIS COULD REDUCE VISIBILITY AS WELL. MY SNOW AMOUNTS MATCH UP
FAIRLY WELL WITH THE LATEST WPC GUIDANCE...WITH NEAR ONE INCH IN OUR
EAST TO THE 2 TO 4 INCH RANGE IN OUR WESTERN HALF OF THE CWA.
CONSIDERING THE GENERAL AGREEMENT BETWEEN THE NAM...NMM WRF...AND
SREF ENSEMBLES...I HAVE BUMPED UP CHANCES OF PRECIPITATION/SNOW
CONSIDERABLY...ESPECIALLY IN OUR SOUTHWEST FOR THIS AFTERNOON INTO
TONIGHT...BUT ALSO DELAYING THE ARRIVAL IN OUR SOUTHEAST A BIT
LONGER...CONSIDERING THAT THE NORTHERN BATCH OF SNOW SHOULD LOSE ITS
PUNCH BEFORE LONG. ALSO RAISED HIGH TEMPERATURES IN OUR NORTH
COMPARED TO THE PREVIOUS FORECAST... SINCE TEMPERATURES
ARE CURRENTLY 5 TO 7 DEGREES WARMER THAN THE EARLIER PREDICTED HIGH
FOR TODAY.
CONSIDERING THAT THE WIND SPEEDS WILL BE A BIT ELEVATED...EVEN LATE
TONIGHT...I DO NOT ANTICIPATE THAT LOWS WILL GET QUITE AS COOL AS
EARLIER PREDICTED...IN GENERAL...AND I HAVE BUMPED UP LOWS A COUPLE
OF DEGREES. I AM QUITE SKEPTICAL OF THE MID-LEVEL SKY COVER
ADVERTISED BY MODEL SOUNDINGS. MID-LEVEL SKY COVER IS FORECAST TO
HANG AROUND...DESPITE MUCH MORE DRY AND COLDER ARCTIC AIR IS MOVING
IN. I SUSPECT AT LEAST PARTIAL CLEARING COULD OCCUR IN OUR
NORTH/NORTHEAST BY THE END OF THE NIGHT. WITH THE WIND SPEEDS
ELEVATED...THIS ALONE SHOULD NOT HAVE AS MUCH OF AN EFFECT. HAVING
SAID THIS...WIND SPEEDS SHOULD BE HIGH ENOUGH TO NEED A WIND CHILL
ADVISORY ALONG AND NORTH OF HIGHWAY 6 LATE TONIGHT INTO TUESDAY
MORNING.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 530 AM CST MON DEC 29 2014
THE PRIMARY FORECAST CONCERN WILL CENTER AROUND THE BITTERLY COLD
TEMPERATURES TUESDAY THROUGH WEDNESDAY.
TUESDAY...SEVERAL FORECAST MODELS (00Z GEM...00Z ECMWF...06Z
NAM...AND A FEW WRF RUNS) ARE LINGERING THE LIGHT SNOW ACROSS OUR
SOUTHWESTERN ZONES INTO THE DAYLIGHT HOURS TUESDAY MORNING.
THEREFORE...HAVE INCREASED SNOW CHANCES TUESDAY MORNING ACROSS
SOUTHWESTERN ZONES...SOUTHWEST OF THE TRI-CITIES. SNOW WILL BE IN
THE PROCESS OF ENDING FROM NORTH TO SOUTH TUESDAY MORNING WITH ANY
ADDITIONAL ACCUMULATION AFTER SUNRISE TUESDAY MORNING LIKELY LESS
THAN ONE HALF INCH AND PRIMARILY CONFINED TO COUNTIES CURRENTLY
UNDER THE WINTER WEATHER ADVISORY. THE MORE WIDESPREAD ISSUE ACROSS
OUR FORECAST AREA WILL BE THE COLD AS WIND CHILL VALUES WILL LIKELY
FALL INTO THE -20 TO -30F RANGE ACROSS MOST OF OUR NEBRASKA COUNTIES
EXCEPT FOR THE SOUTHERN MOST TIER OF COUNTIES. OUR WIND CHILL
ADVISORY CRITERIA IS -20 TO -30F AND THEREFORE A WIND ADVISORY IS
NOW IN EFFECT FOR MOST OF OUR NEBRASKA COUNTIES FROM LATE TONIGHT
THROUGH TUESDAY MORNING. A NORTH WIND OF AROUND 15 TO 20 MPH GUSTING
TO AROUND 25 MPH ALONG WITH TUESDAY MORNING LOWS OF 0 TO -7F SHOULD
BE SUFFICIENT TO PUSH OUR WIND CHILLS DOWN INTO ADVISORY CRITERIA.
COLD AIR WILL CONTINUE TO FILTER INTO THE REGION THROUGHOUT THE DAY
MAKING IT HARD FOR TEMPERATURES TO RISE. IN ADDITION...MID TO HIGH
CLOUDS ARE EXPECTED THROUGH MUCH OF THE DAY AND ALONG WITH OUR
CURRENT SNOW COVER WILL ALSO MAKE IT DIFFICULT FOR TEMPERATURES TO
RISE. THEREFORE...WILL CALL FOR HIGHS ONLY IN THE 5 TO 10F RANGE.
TUESDAY NIGHT INTO WEDNESDAY...THE COLDEST NIGHT OF THE WEEK WILL
LIKELY BY TUESDAY NIGHT AS WE SEE CLEARING SKIES AND DECREASING
WINDS...WHICH WILL HELP LOWS FALL INTO THE -1 TO -10F RANGE ACROSS
THE FORECAST AREA. ANOTHER WIND CHILL ADVISORY WILL LIKELY BE NEEDED
FOR TUESDAY NIGHT INTO WEDNESDAY MORNING. ALTHOUGH THE WIND WILL BE
LIGHTER...THE AIR TEMPERATURES WILL BE COLDER SO THAT THE WIND CHILL
VALUES TUESDAY NIGHT/WEDNESDAY MORNING WILL LIKELY BE RATHER
COMPARABLE TO THE WIND CHILL VALUES EXPECTED TONIGHT INTO TUESDAY
MORNING. THE MODERATION IF YOU CAN CALL IT THAT WILL BEGIN DURING
THE DAY ON WEDNESDAY WITH A WEST SOUTHWEST WIND HELPING HIGHS TO
CLIMB BACK INTO THE TEENS.
THURSDAY THROUGH SUNDAY...A CUT OFF UPPER AREA OF LOW PRESSURE OVER
THE DESERT SOUTHWEST ON THURSDAY WILL SLOWLY TRACK ACROSS THE
SOUTHERN PLAINS FRIDAY AND SATURDAY...AND INTO THE MISSISSIPPI
VALLEY BY SUNDAY. MOST FORECAST MODELS KEEP THIS STORM TRACK FAR
ENOUGH SOUTH THAT WE WILL LIKELY BE DRY ACROSS OUR FORECAST AREA.
FOR THE SAKE OF A COUPLE OF OUTLYING MODELS WILL ALLOW THE SLIGHT
CHANCE OF SNOW ACROSS SOUTHEASTERN ZONES ON FRIDAY/FRIDAY NIGHT TO
REMAIN IN THE FORECAST...BUT CONFIDENCE IS LOW IN SEEING MEASURABLE
PRECIPITATION. THERE SHOULD BE SOME ADDITIONAL MODERATION IN
TEMPERATURES THURSDAY THROUGH SATURDAY AHEAD OF THE SOUTHERN STORM
SYSTEM WITH COLDER AIR FILTERING BACK IN BEHIND THE DEPARTING
SOUTHERN STORM SYSTEM ON SUNDAY. OVERALL...IT WILL REMAIN A COLD
PERIOD WITH HIGHS GENERALLY IN THE 20S FOR MOST AREAS...TO MAYBE
LOWER 30S SOUTH.
&&
.AVIATION...(FOR THE 12Z KGRI/KEAR TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 541 AM CST MON DEC 29 2014
CONFIDENCE IF LOW FOR TIMING OF IFR CONDITIONS...BUT RATHER HIGH
THAT WE WILL EXPERIENCE IFR CONDITIONS AT SOME POINT. KEAR WILL
LAG BEHIND KGRI FOR INITIAL START OF SNOW THIS MORNING AS A BATCH
MOVES IN FROM THE NORTH...BUT SHOULD HANG ON TO SNOW LONGER AS THE
SNOW EVENTUALLY IS RELEGATED FARTHER SOUTHWEST FROM INCREASINGLY
DRY AIR BEING SHOVED SOUTH.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO NOON CST TUESDAY
FOR NEZ039>041-046>049-060>064-072>077.
WINTER WEATHER ADVISORY FROM NOON TODAY TO 9 AM CST TUESDAY FOR
NEZ082-083.
KS...WINTER WEATHER ADVISORY FROM NOON TODAY TO 9 AM CST TUESDAY FOR
KSZ005-017-018.
&&
$$
SHORT TERM...HEINLEIN
LONG TERM...WESELY
AVIATION...HEINLEIN
AREA FORECAST DISCUSSION
NWS HASTINGS NE
531 AM CST MON DEC 29 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 530 AM CST MON DEC 29 2014
THE SHORT TERM IS A BIT COMPLICATED. A COLD FRONT PASSED SOUTH
ACROSS THE CWA OVERNIGHT AND LIGHT SNOW HAS BROKEN OUT BEHIND IT.
MODELS ARE TRENDING LATER WITH THE BEGINNING OF SNOW. THE NAM AND
WRF...ALONG WITH THE HRRR INDICATE THAT THE SNOW ENTERING FROM THE
NORTH WILL HAVE A TOUGH TIME MAKING IT MUCH FARTHER SOUTH THAN
INTERSTATE 80 THIS AFTERNOON. AS THIS AREA OF SNOW STALLS AND
DISSIPATES...A MID-LEVEL PERTURBATION HEADS IN FROM THE WEST ACROSS
NORTHERN KANSAS ALONG WITH AN UPPER LEVEL JET MAXIMUM WILL HELP GET
SNOW GOING AGAIN...ESPECIALLY IN OUR FAR SOUTHWESTERN CWA. WE COULD
GET CLOSE TO THREE INCHES OF SNOW IN THESE AREAS...CONSIDERING A
GENERAL ENSEMBLE APPROACH TO MODEL QPF...ALONG WITH SNOW/LIQUID
WATER RATIOS 13 TO 1 FOR TONIGHT...WHICH IS FAIRLY TYPICAL. WENT
WITH A WINTER WEATHER ADVISORY IN OUR SOUTHWEST...CONSIDERING NOT
ONLY WE SHOULD JUST MEET SNOWFALL AMOUNT CRITERION...BUT THE
PRESSURE GRADIENT TODAY WILL BRING IN WIND FROM THE NORTH AT AROUND
20 MPH GUSTING TO 30 MPH. NUMERICAL MODELS ARE TRENDING LATER WITH
ENDING TIME...AND HAVE CONTINUED THIS ADVISORY INTO TUESDAY MORNING.
THIS COULD REDUCE VISIBILITY AS WELL. MY SNOW AMOUNTS MATCH UP
FAIRLY WELL WITH THE LATEST WPC GUIDANCE...WITH NEAR ONE INCH IN OUR
EAST TO THE 2 TO 4 INCH RANGE IN OUR WESTERN HALF OF THE CWA.
CONSIDERING THE GENERAL AGREEMENT BETWEEN THE NAM...NMM WRF...AND
SREF ENSEMBLES...I HAVE BUMPED UP CHANCES OF PRECIPITATION/SNOW
CONSIDERABLY...ESPECIALLY IN OUR SOUTHWEST FOR THIS AFTERNOON INTO
TONIGHT...BUT ALSO DELAYING THE ARRIVAL IN OUR SOUTHEAST A BIT
LONGER...CONSIDERING THAT THE NORTHERN BATCH OF SNOW SHOULD LOSE ITS
PUNCH BEFORE LONG. ALSO RAISED HIGH TEMPERATURES IN OUR NORTH
COMPARED TO THE PREVIOUS FORECAST... SINCE TEMPERATURES
ARE CURRENTLY 5 TO 7 DEGREES WARMER THAN THE EARLIER PREDICTED HIGH
FOR TODAY.
CONSIDERING THAT THE WIND SPEEDS WILL BE A BIT ELEVATED...EVEN LATE
TONIGHT...I DO NOT ANTICIPATE THAT LOWS WILL GET QUITE AS COOL AS
EARLIER PREDICTED...IN GENERAL...AND I HAVE BUMPED UP LOWS A COUPLE
OF DEGREES. I AM QUITE SKEPTICAL OF THE MID-LEVEL SKY COVER
ADVERTISED BY MODEL SOUNDINGS. MID-LEVEL SKY COVER IS FORECAST TO
HANG AROUND...DESPITE MUCH MORE DRY AND COLDER ARCTIC AIR IS MOVING
IN. I SUSPECT AT LEAST PARTIAL CLEARING COULD OCCUR IN OUR
NORTH/NORTHEAST BY THE END OF THE NIGHT. WITH THE WIND SPEEDS
ELEVATED...THIS ALONE SHOULD NOT HAVE AS MUCH OF AN EFFECT. HAVING
SAID THIS...WIND SPEEDS SHOULD BE HIGH ENOUGH TO NEED A WIND CHILL
ADVISORY ALONG AND NORTH OF HIGHWAY 6 LATE TONIGHT INTO TUESDAY
MORNING.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 530 AM CST MON DEC 29 2014
THE PRIMARY FORECAST CONCERN WILL CENTER AROUND THE BITTERLY COLD
TEMPERATURES TUESDAY THROUGH WEDNESDAY.
TUESDAY...SEVERAL FORECAST MODELS (00Z GEM...00Z ECMWF...06Z
NAM...AND A FEW WRF RUNS) ARE LINGERING THE LIGHT SNOW ACROSS OUR
SOUTHWESTERN ZONES INTO THE DAYLIGHT HOURS TUESDAY MORNING.
THEREFORE...HAVE INCREASED SNOW CHANCES TUESDAY MORNING ACROSS
SOUTHWESTERN ZONES...SOUTHWEST OF THE TRI-CITIES. SNOW WILL BE IN
THE PROCESS OF ENDING FROM NORTH TO SOUTH TUESDAY MORNING WITH ANY
ADDITIONAL ACCUMULATION AFTER SUNRISE TUESDAY MORNING LIKELY LESS
THAN ONE HALF INCH AND PRIMARILY CONFINED TO COUNTIES CURRENTLY
UNDER THE WINTER WEATHER ADVISORY. THE MORE WIDESPREAD ISSUE ACROSS
OUR FORECAST AREA WILL BE THE COLD AS WIND CHILL VALUES WILL LIKELY
FALL INTO THE -20 TO -30F RANGE ACROSS MOST OF OUR NEBRASKA COUNTIES
EXCEPT FOR THE SOUTHERN MOST TIER OF COUNTIES. OUR WIND CHILL
ADVISORY CRITERIA IS -20 TO -30F AND THEREFORE A WIND ADVISORY IS
NOW IN EFFECT FOR MOST OF OUR NEBRASKA COUNTIES FROM LATE TONIGHT
THROUGH TUESDAY MORNING. A NORTH WIND OF AROUND 15 TO 20 MPH GUSTING
TO AROUND 25 MPH ALONG WITH TUESDAY MORNING LOWS OF 0 TO -7F SHOULD
BE SUFFICIENT TO PUSH OUR WIND CHILLS DOWN INTO ADVISORY CRITERIA.
COLD AIR WILL CONTINUE TO FILTER INTO THE REGION THROUGHOUT THE DAY
MAKING IT HARD FOR TEMPERATURES TO RISE. IN ADDITION...MID TO HIGH
CLOUDS ARE EXPECTED THROUGH MUCH OF THE DAY AND ALONG WITH OUR
CURRENT SNOW COVER WILL ALSO MAKE IT DIFFICULT FOR TEMPERATURES TO
RISE. THEREFORE...WILL CALL FOR HIGHS ONLY IN THE 5 TO 10F RANGE.
TUESDAY NIGHT INTO WEDNESDAY...THE COLDEST NIGHT OF THE WEEK WILL
LIKELY BY TUESDAY NIGHT AS WE SEE CLEARING SKIES AND DECREASING
WINDS...WHICH WILL HELP LOWS FALL INTO THE -1 TO -10F RANGE ACROSS
THE FORECAST AREA. ANOTHER WIND CHILL ADVISORY WILL LIKELY BE NEEDED
FOR TUESDAY NIGHT INTO WEDNESDAY MORNING. ALTHOUGH THE WIND WILL BE
LIGHTER...THE AIR TEMPERATURES WILL BE COLDER SO THAT THE WIND CHILL
VALUES TUESDAY NIGHT/WEDNESDAY MORNING WILL LIKELY BE RATHER
COMPARABLE TO THE WIND CHILL VALUES EXPECTED TONIGHT INTO TUESDAY
MORNING. THE MODERATION IF YOU CAN CALL IT THAT WILL BEGIN DURING
THE DAY ON WEDNESDAY WITH A WEST SOUTHWEST WIND HELPING HIGHS TO
CLIMB BACK INTO THE TEENS.
THURSDAY THROUGH SUNDAY...A CUT OFF UPPER AREA OF LOW PRESSURE OVER
THE DESERT SOUTHWEST ON THURSDAY WILL SLOWLY TRACK ACROSS THE
SOUTHERN PLAINS FRIDAY AND SATURDAY...AND INTO THE MISSISSIPPI
VALLEY BY SUNDAY. MOST FORECAST MODELS KEEP THIS STORM TRACK FAR
ENOUGH SOUTH THAT WE WILL LIKELY BE DRY ACROSS OUR FORECAST AREA.
FOR THE SAKE OF A COUPLE OF OUTLYING MODELS WILL ALLOW THE SLIGHT
CHANCE OF SNOW ACROSS SOUTHEASTERN ZONES ON FRIDAY/FRIDAY NIGHT TO
REMAIN IN THE FORECAST...BUT CONFIDENCE IS LOW IN SEEING MEASURABLE
PRECIPITATION. THERE SHOULD BE SOME ADDITIONAL MODERATION IN
TEMPERATURES THURSDAY THROUGH SATURDAY AHEAD OF THE SOUTHERN STORM
SYSTEM WITH COLDER AIR FILTERING BACK IN BEHIND THE DEPARTING
SOUTHERN STORM SYSTEM ON SUNDAY. OVERALL...IT WILL REMAIN A COLD
PERIOD WITH HIGHS GENERALLY IN THE 20S FOR MOST AREAS...TO MAYBE
LOWER 30S SOUTH.
&&
.AVIATION...(FOR THE 06Z KGRI/KEAR TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1158 PM CST SUN DEC 28 2014
TRENDS ARE LATER FOR ARRIVAL OF SNOW FROM THE MID-LEVEL SYSTEM
COMING THROUGH. EXPECT IFR CONDITIONS FOR A GOOD PORTION OF DAY ON
MONDAY...AND SNOW WILL LIKELY CONTINUE WELL INTO THE EVENING AS
CEILINGS AND VISIBILITY IMPROVE.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO NOON CST TUESDAY
FOR NEZ039>041-046>049-060>064-072>077.
WINTER WEATHER ADVISORY FROM NOON TODAY TO 9 AM CST TUESDAY FOR
NEZ082-083.
KS...WINTER WEATHER ADVISORY FROM NOON TODAY TO 9 AM CST TUESDAY FOR
KSZ005-017-018.
&&
$$
SHORT TERM...HEINLEIN
LONG TERM...WESELY
AVIATION...HEINLEIN
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
820 PM EST TUE DEC 30 2014
.SYNOPSIS...
A WESTERLY FLOW OF COLD AIR ACROSS LAKE ONTARIO WILL DEVELOP LAKE
EFFECT SNOW TONIGHT WHICH WILL IMPACT NORTHERN ONEIDA COUNTY. MUCH
OF THE REST OF THE AREA WILL REMAIN DRY WITH ONLY SCATTERED SNOW
SHOWERS AND FLURRIES FROM TIME TO TIME.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
820 PM UPDATE...
LAKE EFFECT SNOW BAND IS SHOWING ITS FIRST SIGNS OF ORGANIZATION
OVER NORTHEASTERN LAKE ONTARIO. MADE SLIGHT CHANGES TO THE GRIDS
AND TO THE WSW TEXT TO BRING THE STEADY SNOW INTO NORTHWESTERN
ONEIDA COUNTY SOMETIME BETWEEN 11 PM AND 2 AM. NAM AND RAP RADAR
OUTPUT SUGGEST THIS IS A LIKELY TIME WINDOW.
THE BAND WILL FLUCTUATE QUITE A BIT OVERNIGHT, SO NOT CONFIDENT
THAT ACCUMULATIONS WILL BE SIGNIFICANT BY MORNING. THE BAND SHOWS
BETTER ALIGNMENT AND A STEADIER STATE AFTER SUNRISE.
4 PM UPDATE...
AFTER A FINAL BURST...NW FLOW LE EVENT OVER THE CNTRL ZONES IS
FINALLY WINDING DOWN. ALREADY EVIDENCE OF BACKING FLOW OVER WRN NY
WHICH WILL END THE CNTRL NY SNOW...AND BEGIN TO DVLP THE SINGLE
BAND LE EVENT XPCTD LTR TNGT AND WED. MODELS AND FCST OFFICES IN
GNRL AGREEMENT ON THE IDEA THAT A SINGLE BAND WILL DVLP AFT 00Z.
DFCLTY IS IN THE PLACEMENT OF THE BAND WITH A MEAN FLOW ARND
260-270 WHICH SHD JUST CLIP THE POINTS IN NRN ONEIDA COUNTY.
ALSO...MODEL FCSTD REFLECTIVITY AND QPF HAS A LIMITED INLAND
EXTENT OF THE HEAVIER BANDS. FOR THAT REASON...XPCT THE HEAVIEST
SNOW IN THE FAR NE CORNER OF NYZ009...WITH LESSER AMTS BUT STILL
ARND WARNING CRITERIA OVER THE NW. TIMING BRINGS THE BAND INTO THE
WARNING AREA BETWEEN 03Z AND 06Z. BAND MAY BRIEFLY LFT NORTH ARND
DAYBRK AS A WV ZIPS BY BEFORE SETTLING BACK IN THE NRN PARTS OF
ONEIDA FOR MUCH OF THE REST OF THE DAY. LOOKS LIKE THE BAND LFTS
OUT FOR GOOD AFT 21Z.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
SOUTHWEST FLOW CONTS WED NGT INTO THU KEEPING LAKE ERIE AND
ONTARIO BAND OUT OF THE AREA. SOME LIFT OVER THE TERRAIN...ESP THE
WRN CATS...COULD GENERATE SOME LGTR FLURRIES AT TIMES...AND THE
FINGER LAKES COULD SEE A BOT OF LGT SNOW SHWR ACTIVITY AT THE EDGE
OF THE LE.
SHRT WV THU NGT AND EARLY FRI WILL BRING A MORE NWLY FLOW AND A
RE-ENFORCING SHOT OF COLD AIR. THIS SHD HELP BRING MORE WIDESPREAD
SNOW SHWRS AND FLURRIES TO THE FCST AREA LATE THU NGT AND ON FRI.
WITH THE BROAD TROFF OVER THE AREA AND ARCTIC SOURCE REGION FOR
OUR AIR...TEMPS SHD AVG BLO NRML THRU THE SHRT TERM PD.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
230 PM UPDATE...
HIPRES WL START OFF THE LONG TERM PORTION OF THE FCST. 1040MB SFC
HIGH WL RESULT IN COLD-AIR DAMMING BFR NEXT STORM SYSTEM MVS IN FOR
LATE IN THE WEEKEND. H5 S/WV EJECTS OUT OF THE SRN PLAINS ON
SATURDAY AND LOOKS TO PHASE WITH WV DROPPING DOWN THRU THE UPR
MIDWEST. MED RANGE MODELS COMING INTO BETTER AGREEMENT WITH SFC
CYCLOGENESIS OCCURRING IN VICINITY OF GREAT LKS 06Z SUNDAY.
MOISTURE WL ENTER CWA AFT 18Z SAT IN THE FORM OF RAIN/SNOW, MAINLY
SNOW ACRS THE COLD-AIR DAMMED ERN ZONES. WARM AIR WRAPS IN RAPIDLY
LATE SAT NGT WITH A WINTRY MESS EXPECTED THRU 12Z SUN BFR DRY SLOT
WORKS IN.
AFT SYSTEM DEPARTS JUST EXPECTING WRAP-ARND SHOWERS ON SUNDAY. WITH
COLD-AIR FILTERING IN BHND EXPECT A VRY GRADUAL CHANGEOVER TO SNOW
SHOWERS THRU THE AFTN. BY 00Z MONDAY JUST EXPECT LK EFFECT SNOW
SHOWERS THROUGH THE END OF THE LONG TERM.
TEMPS WL BE TRICKY THRU THE PD. TEMPS WL BE NEAR TO SLIGHTLY ABV
NORMAL FOR THE WEEKEND. CANNOT RULE OUT A NON-DIURNAL TEMP TREND FOR
SAT NGT AS TEMPS WARM WITH SYSTEM PASSING TO THE WEST. BHND LOW
TEMPS DROP DOWN TO BLO NORMAL VALUES AGAIN INTO EARLY NEXT WEEK.
&&
.AVIATION /01Z WEDNESDAY THROUGH SUNDAY/...
A MESO LOW AND ITS ASSOCIATED SFC TROF WILL TRACK ACROSS LAKE
ONTARIO OVERNIGHT. ONCE THIS BOUNDARY MOVES THROUGH A LAKE EFFECT
SNOWBAND WILL DEVELOP OFF LAKE ONTARIO BUT THE BULK OF THIS ACTIVITY
WILL REMAIN NORTH OF THE KRME/KSYR TERMINALS. AS THIS LOW TRACKS
ACROSS THE LAKE TONIGHT MVFR SNOW SHOWERS WILL BE POSSIBLE AT
KSYR/KRME BETWEEN 04Z-08Z. ON WED, BETWEEN MID MORNING THROUGH EARLY
AFTERNOON THE LAKE EFFECT SNOWS MAY BRIEFLY BE IN THE VCNTY OF
KRME, INCLUDED A TEMPO GROUP FOR IFR SNOW SHOWERS BETWEEN 14Z-18Z.
OTHERWISE CONDITIONS WILL BE PRIMARILY LOW VFR WITH SCATTERED
FLURRIES.
LIGHT AND VARIABLE WINDS BECOMING SOUTHWEST AROUND 10 KNOTS LATE
TONIGHT THEN INCREASING SHORTLY AFTER SUNRISE FROM THE WEST AT
10-15 KNOTS WITH GUSTS NEAR 20 KNOTS.
OUTLOOK...
WED NIGHT THRU FRI...RESTRICTIONS POSSIBLE AT TIMES FOR KRME/KSYR
DUE TO MEANDERING LAKE EFFECT -SHSN. OTHERWISE VFR IS EXPECTED.
SAT/SAT NGT...CHANCE FOR MIXED PRECIP AND ASSOCIATED RESTRICTIONS.
SUN...MVFR RESTRICTIONS POSSIBLE IN LIGHT SNOW SHOWERS BEHIND
DEPARTING SYSTEM.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...LAKE EFFECT SNOW WARNING UNTIL 7 PM EST WEDNESDAY FOR NYZ009.
&&
$$
SYNOPSIS...DGM/DJP
NEAR TERM...DGM
SHORT TERM...DGM
LONG TERM...PVF
AVIATION...RRM
AREA FORECAST DISCUSSION
NWS BUFFALO NY
658 PM EST TUE DEC 30 2014
.SYNOPSIS...
ARCTIC AIR WILL ARRIVE TONIGHT BRINGING LAKE EFFECT SNOW TONIGHT
THROUGH THURSDAY NIGHT EAST OF THE LAKES. THE COMBINATION OF ARCTIC
AIR AND GUSTY WINDS WILL PUSH WIND CHILL TEMPERATURES TO NEAR ZERO
WEDNESDAY NIGHT AS WE TURN THE CALENDAR TO 2015.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
FOR THE REMAINDER OF THIS EVENING...OBSERVATIONS SHOW A SUBTLE
SURFACE CONVERGENCE BOUNDARY FOCUSING ACROSS SOUTHERN ERIE AND
WYOMING COUNTIES. THIS APPEARS TO BE TEMPORARY...BUT IS LIKELY TO
BRING AN INCH OR TWO OF SNOW TO THESE AREAS THIS EVENING BEFORE
WINDS BECOME MORE WESTERLY WHICH SHOULD DISRUPT AND PUSH THE BAND TO
THE SOUTH. THIS IS SHOWN BY THE HRRR AND IS LIKELY UNDERWAY BASED
ON THE WIND SHIFT AT DKK. AFTER THIS...EXPECT GENERALLY LIGHT SNOW
SHOWERS FOR THE REMAINDER OF THE EVENING OFF LAKE ERIE. RADAR ALSO
SHOWS A MESO LOW DEVELOPED ACROSS CENTRAL PORTIONS OF LAKE
ONTARIO. MOST HIGH RESOLUTION GUIDANCE HAS FORECAST THIS...WITH IT
LIKELY TO CONTINUE TO TRACK EAST AND INTENSIFY PER A CONSENSUS OF
THIS GUIDANCE. THIS SHOULD BRING A BURST OF MODERATE TO HEAVY SNOW
WHICH WILL PUSH ONSHORE EAST OF LAKE ONTARIO BETWEEN 9 AND 10 PM.
THIS WILL PRECEDE ORGANIZED LAKE EFFECT BANDS AND LIKELY IMPACT A
LARGER AREA FOR A COUPLE HOURS BEFORE IT FALLS APART AS IT MOVES
FURTHER EAST OF THE LAKE. IT MAY BRING A QUICK 2 TO 3 INCHES OF
SNOW TO SOME AREAS BETWEEN OSWEGO AND WATERTOWN LATE THIS EVENING.
AFTER THIS...OUR FOCUS TURNS TO MORE ORGANIZED LAKE EFFECT SNOW
WHICH SHOULD CONTINUE THROUGH THURSDAY NIGHT. LAKE EFFECT SNOW
WARNINGS ARE IN PLACE EAST OF LAKE ONTARIO...AND A LAKE EFFECT
SNOW WATCH IS IN PLACE EAST OF LAKE ERIE...INCLUDING THE BUFFALO
METRO AREA.
A SHORTWAVE IN CYCLONIC FLOW ALOFT WILL PUSH ACROSS THE FORECAST
AREA OVERNIGHT. THE LOW-LEVEL FLOW WILL BE WESTERLY AS THIS WAVE
APPROACHES AND PASSES THE FORECAST AREA...AND THE WAVE WILL PROVIDE
SOME WEAK SYNOPTIC FORCING. COLDER ARCTIC SOURCED AIR WILL ADVECT
ACROSS THE FORECAST AREA WITH 850 MB TEMPERATURES FALLING TO AROUND
-18 C BY WEDNESDAY MORNING. THE WESTERLY FLOW WILL TURN MORE
SOUTHWESTERLY BY WEDNESDAY AFTERNOON THROUGH WEDNESDAY NIGHT A
STRONGER SHORTWAVE TROUGH APPROACHES THE FORECAST AREA AND A POLAR
LOW SETTLES OVER HUDSON BAY. LONG STORY SHORT...PLENTY OF COLD AIR
WILL BE AROUND THROUGH THURSDAY NIGHT MAKING FOR AN ACTIVE LAKE
EFFECT PERIOD.
...OFF OF LAKE ONTARIO...
FORECAST REMAINS ON TRACK FOR THE LAKE EFFECT SNOW WARNING IN PLACE
EAST OF LAKE ONTARIO. INITIALLY 270-280 DEGREE FLOW WILL SET UP
SHORTLY AFTER MIDNIGHT BEHIND THE EXITING MESO-LOW. LAKE INDUCED
EQUILIBRIUM LEVELS RISE TO 10 TO 12KFT BY MORNING WITH PLENTY OF
MOISTURE AND LIFT THROUGH THE DENDRITIC GROWTH ZONE...WHICH WILL
ONLY BE ABOUT 2 TO 5 KFT OFF THE GROUND. LATEST HIGH RESOLUTION
MODELS CONTINUE TO PICK UP ON THIS STRONG LAKE EFFECT SNOW
BAND...WITH THE HIGH RES NMM / CANADIAN GEM AND THE NAM HANDLING
THE POSITION / INTENSITY FAIRLY WELL. FORECASTER CONFIDENCE
REMAINS HIGH IN A WARNING EVENT OFF LAKE ONTARIO...WITH 1 TO 2
FEET OF SNOW AND 2 OR MORE FEET OVER THE TUG HILL PLATEAU. SNOW
RATES COULD REACH 2 TO 4 INCHES AN HOUR AT TIMES LATE TONIGHT INTO
EARLY WEDNESDAY MORNING. EXPECT THIS LAKE BAND WILL MAKE A
NORTHWARD PUSH DURING THE DAY WEDNESDAY AS THE FLOW TURNS MORE
SOUTHWESTERLY.
...OFF OF LAKE ERIE...
LATER TONIGHT A SHORTWAVE WILL CROSS THE REGION AND LIGHTLY
ENHANCE SNOWFALL A BIT. UNTIL THIS...EXPECT LIGHT AND RELATIVELY
DISORGANIZED BANDS...WITH SOME LIGHT ACCUMULATIONS WITH THIS BAND
LATE TONIGHT INTO WEDNESDAY MORNING. TRANSIENT BANDS SHOULD HOLD
DOWN SNOW ACCUMULATION THROUGH WEDNESDAY MORNING TO BELOW ADVISORY
CRITERIA...THOUGH IT STILL NEEDS TO BE MONITORED IN CASE A BAND
STALLS OVER THE SAME LOCATIONS.
A LAKE EFFECT SNOW WATCH REMAINS IN EFFECT EAST OF LAKE
ERIE...INCLUDING THE BUFFALO METRO AREA FROM WEDNESDAY AFTERNOON
THROUGH THURSDAY NIGHT. FORECAST CONFIDENCE IS SLOWLY INCREASING
FOR A STRONG SINGLE LAKE EFFECT SNOW BAND TO DEVELOP OFF OF LAKE
ERIE BY LATE WEDNESDAY AFTERNOON AS THE FLOW TURNS MORE
SOUTHWESTERLY AHEAD OF THE APPROACHING SHORTWAVE AND ALIGNS WITH
LONG AXIS OF THE LAKE. A 230 TO 240 WIND DIRECTION BY WEDNESDAY
EVENING SHOULD ALIGN THE LAKE EFFECT BAND RIGHT THROUGH THE HEART
OF THE BUFFALO METRO AREA. LAKE INDUCED EQUILIBRIUM LEVELS ARE NOT
QUITE AS IMPRESSIVE AS OFF OF LAKE ONTARIO...BUT STILL APPROACH
ALMOST 10KFT WEDNESDAY EVENING. THE BIGGEST POINT OF UNCERTAINTY
HAS BEEN THE AMOUNT OF SYNOPTIC MOISTURE AVAILABLE FOR LAKE
ERIE...BUT THE MODELS HAVE BEEN TRENDING MORE MOIST...AND THUS
THIS HAS HELPED FORECAST CONFIDENCE.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
LAKE EFFECT SNOWS WILL BE RAMPING UP NICELY NEW YEARS EVE AS A
SOUTHWEST FLOW AROUND 230-240 DEGREES BECOMES BETTER ALIGNED ACROSS
THE LOWER LAKES. THE HEAVIEST ACTIVITY OFF LAKE ONTARIO WILL BE
FOCUSING ON NORTHERN JEFFERSON INCLUDING WATERTOWN AND LEWIS
COUNTIES THIS TIME. LATEST MODEL GUIDANCE IS SUGGESTING AN UPSTREAM
CONNECTION TO LAKE ERIE THAT MAY ENHANCE SNOWFALL RATES. SNOW RATES
IN EXCESS OF 3 INCHES PER HOUR WILL BE POSSIBLE WITH THIS LAKE BAND.
IN ADDITION...THE SOUTHWEST WINDS WILL BE A GOOD BIT STRONGER WITH
GUSTS OF 30 TO 40 MPH POSSIBLE WEDNESDAY NIGHT INTO THURSDAY
MORNING...AND THIS WILL PRODUCE BLOWING AND DRIFTING OF SNOW...
FURTHER ADDING TO THE HAZARDOUS DRIVING CONDITIONS.
OFF LAKE ERIE...WITH THE FLOW BACKING INTO THE 230-240 DEGREE RANGE
WEDNESDAY NIGHT...A HEAVY LAKE EFFECT SNOW BAND WILL FOCUS ON THE
METRO BUFFALO AREA...WHICH COULD PROVE QUITE IMPACTFUL BASED ON THE
TIMING RELATED TO THE NEW YEAR HOLIDAY. SNOW RATES OF UP TO 2 INCHES
AN HOUR ARE POSSIBLE WITH THIS LAKE BAND. PERHAPS OF GREATER CONCERN
WILL BE THE STRONG SOUTHWEST WINDS WHICH WILL DEVELOP AS THE
PRESSURE GRADIENT ACROSS THE REGION TIGHTENS BETWEEN HIGH PRESSURE
OVER THE SOUTHERN U.S. AND A BROAD AND DEEP VERTICALLY STACKED LOW
PRESSURE SYSTEM DESCENDING OUT OF THE CANADIAN ARCTIC AND ACROSS
HUDSON BAY. WINDS GUSTING UPWARDS OF 45 MPH WILL POTENTIALLY PRODUCE
SIGNIFICANT AREAS OF BLOWING AND DRIFTING SNOW ALONG WITH WIND
CHILLS TO NEAR ZERO.
LAKE EFFECT SNOWS WILL CONTINUE THURSDAY AND THURSDAY NIGHT...WITH
THE USUAL DIURNAL WEAKENING REDUCING ORGANIZATION/INTENSITY OF
ACTIVITY DURING THE DAY ON THURSDAY WITH ACTIVITY LIKELY
RE-INTENSIFYING THURSDAY NIGHT EVEN AS FLOW ONCE AGAIN VEERS TO THE
WEST IN RESPONSE TO THE PASSAGE OF AN UPPER SHORTWAVE. THIS WILL
SHIFT THE MOST INTENSE ACTIVITY TO THE SOUTHERN TUG HILL AND
CHAUTAUQUA RIDGE AREAS AND PERHAPS NECESSITATING ADDITIONAL LAKE
EFFECT HEADLINES FOR THESE AREAS.
THE LAKE BANDS WILL GRADUALLY WEAKEN DURING THE DAY FRIDAY AS A
WARM AIR ADVECTION PATTERN SETS UP.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
THE PRIMARY FOCUS FOR THE WEEKEND AND INTO EARLY NEXT WEEK WILL
CONTINUE TO REVOLVE AROUND THE EVOLUTION OF THE CUT OFF SOUTHWEST
CONUS PV ANOMALY AND ASSOCIATED PRECIPITATION CHANCES. BULK OF THE
MEDIUM RANGE MODELS/ENSEMBLES STILL KEEPS MORE OF A BLOCKED PATTERN
IN PLACE THROUGH FRIDAY NIGHT. THIS SHOULD ALLOW FOR A CONTINUED
WEAK LAKE SNOW POTENTIAL EAST OF LAKE ONTARIO.
FORECAST CONFIDENCE STILL REMAINS LOW GOING FORWARD DURING THE
WEEKEND TIME FRAME WITH THE LATEST 12Z SUITE OF GUIDANCE NOW
DEPICTING A MORE SUBSTANTIAL NORTHERN STREAM TROUGH ACROSS NORTH
CENTRAL CONUS ALLOWING FOR PHASING OR PARTIAL PHASING OF SOUTHWEST
CONUS PV ANOMALY...AND A FURTHER NORTH SOLUTION. MUCH OF THIS LOWER
CONFIDENCE CONTINUES TO STEM FROM A HIGH DEGREE OF UNCERTAINTY OF
HOW THE NORTHERN STREAM WILL MATERIALIZE...WITH ORIGINS OF THE
NORTHERN STREAM WAVE RESPONSIBLE FOR BETTER PHASING DEPICTED BY 12Z
MODEL GUIDANCE STILL SOUTH OF ALEUTIAN ISLANDS. THUS...REALLY CANNOT
MAKE SUBSTANTIAL CHANGES TO MID RANGE PRECIPITATION PROBABILITIES
DURING THE WEEKEND PERIOD WITH A POTENTIAL OF A LEAD WARM AIR
ADVECTION/MOISTURE SURGE INTO THE OHIO VALLEY/EASTERN GREAT LAKES
SOME TIME SATURDAY NIGHT/SUNDAY. WITH ALL THE UNCERTAINTIES IN
NORTHWEST FLOW/PHASING...IT REMAINS TOO EARLY TO TRY AND RESOLVE ANY
PRECIPITATION TYPE TRENDS...ALTHOUGH POTENTIAL WOULD EXIST FOR
WINTRY MIX (POSSIBLY SIGNIFICANT) WITH THIS WARM ADVECTION SURGE IF
IT DOES MATERIALIZE DURING THE WEEKEND...AND CERTAINLY A SYSTEM THAT
WILL NEED WATCHING GOING FORWARD THIS WEEK.
BEYOND THE WEEKEND...THERE DOES SEEMS TO BE FAIRLY GOOD MODEL
AGREEMENT IN A STRONGER WEST-NORTHWEST FLOW DEVELOPING ON THE
BACKSIDE OF THE DEEPENING SURFACE LOW ALONG WITH STRONG COLD AIR
ADVECTION DROPPING 850 MB TEMPERATURES TO -20C BY MONDAY AFTERNOON.
THIS WILL ALLOW FOR THE POTENTIAL FOR LAKE SNOWS TO DEVELOP. ONLY
QUESTION THAT REMAINS WILL BE HOW MUCH SYNOPTIC MOISTURE WILL BE
AVAILABLE EARLY NEXT WEEK...BUT THE RISK FOR SIGNIFICANT LAKE SNOWS
IS CERTAINLY A POSSIBILITY.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
IAG/ROC/BUF...EXPECT PRIMARILY VFR CONDITIONS OUTSIDE OF PERHAPS A
BRIEF PERIOD OF VSBY LESS THAN 2SM IN LAKE ENHANCED SNOW SHOWERS
THIS EVENING AND LATE TONIGHT. MORE ORGANIZED LAKE SNOWS MAY
IMPACT BUF...WITH A GOOD CHANCE FOR IFR CONDITIONS FROM THIS LATE
WEDNESDAY. EXPECT PRIMARILY VFR CONDITIONS AT IAG/ROC FOR THROUGH
00Z THU.
ART...EXPECT VFR CONDITIONS TO DETERIORATE AS AN AREA OF LAKE EFFECT
SNOW SHOWERS MOVES IN LATE THIS EVENING. THERE IS LOW FORECAST
CONFIDENCE IN THIS...WITH ART ON THE NORTHERN FRINGE OF THIS.
CONDITIONS MAY VARY...WITH EVEN A PERIOD OF HEAVY SNOW POSSIBLE.
THIS SHOULD FALL APART LATE TONIGHT...WITH ORGANIZED LAKE SNOWS
FOCUSING SOUTH OF THE ART TERMINAL LATE TONIGHT AND WEDNESDAY
MORNING. THIS BAND WILL LIFT NORTH AND LIKELY RESULT IN IFR
CONDITIONS WEDNESDAY AFTERNOON.
JHW...EXPECT VARIABLE CONDITIONS WHICH WILL GENERALLY BE IN THE
IFR/MVFR CATEGORY THROUGH 18Z WEDNESDAY. AFTER THAT...ORGANIZED
LAKE SNOW SHOULD LIFT NORTH OF JHW.
OUTLOOK...
WEDNESDAY NIGHT THROUGH FRIDAY...POSSIBLE IFR IN LAKE EFFECT EAST
OF THE LAKES...MVFR/VFR ELSEWHERE.
SATURDAY AND SUNDAY...VFR/MVFR. CHANCE RAIN/SNOW SHOWERS.
&&
.MARINE...
RELATIVELY LIGHT NORTHWEST WINDS WILL CONTINUE THIS EVENING BEFORE WINDS
BACK TO THE WEST AND STRENGTHEN TONIGHT INTO WEDNESDAY...WITH SMALL
CRAFT ADVISORY CONDITIONS EXPECTED DURING THIS TIME FRAME. WINDS
WILL BACK TO THE SOUTHWEST BY LATE IN THE DAY ON WEDNESDAY AND
STRENGTHEN FURTHER AHEAD OF ANOTHER LOW DROPPING OUT OF THE CANADIAN
ARCTIC. THIS WILL POSSIBLY BRING GALE FORCE WINDS BY LATE WEDNESDAY
NIGHT INTO THURSDAY AND A GALE WATCH HAS BEEN ISSUED.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...LAKE EFFECT SNOW WARNING UNTIL 1 AM EST FRIDAY FOR NYZ007-008.
LAKE EFFECT SNOW WARNING UNTIL 7 PM EST WEDNESDAY FOR NYZ006.
LAKE EFFECT SNOW WATCH FROM WEDNESDAY AFTERNOON THROUGH LATE
THURSDAY NIGHT FOR NYZ010>012-085.
MARINE...GALE WATCH FROM WEDNESDAY AFTERNOON THROUGH LATE THURSDAY
NIGHT FOR LEZ040-041.
SMALL CRAFT ADVISORY UNTIL 5 PM EST WEDNESDAY FOR LEZ040-
041.
SMALL CRAFT ADVISORY FROM 7 PM WEDNESDAY TO 7 PM EST
THURSDAY FOR LEZ020.
GALE WATCH FROM WEDNESDAY AFTERNOON THROUGH LATE
THURSDAY NIGHT FOR LOZ042>045-062>065.
SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 5 PM EST
WEDNESDAY FOR LOZ043.
SMALL CRAFT ADVISORY UNTIL 5 PM EST WEDNESDAY FOR LOZ042.
SMALL CRAFT ADVISORY FROM 1 AM TO 5 PM EST WEDNESDAY FOR
LOZ044-045.
&&
$$
SYNOPSIS...CHURCH
NEAR TERM...APFFEL/CHURCH
SHORT TERM...TMA
LONG TERM...TMA
AVIATION...APFFEL
MARINE...CHURCH/SMITH
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
222 AM EST MON DEC 29 2014
.SYNOPSIS...
A NORTHWEST FLOW OF COLD AIR WILL RETURN THE AREA TO MORE
SEASONABLE WEATHER THIS WEEK. AS THIS AIR CROSSES THE GREAT
LAKES IT WILL PICK UP SOME MOISTURE...SO A FEW LAKE EFFECT SNOW
SHOWERS AND FLURRIES ARE POSSIBLE...ESPECIALLY OVER CENTRAL NEW
YORK.
&&
.NEAR TERM /THROUGH TODAY/...
930 PM UPDATE...
LAKE ENHANCED SNOW SHOWERS NOW ENTERING FAR NORTHERN ONEIDA COUNTY
AS HAD BEEN ANTICIPATED /IF ANYTHING...JUST A SMIDGE AHEAD OF
SCHEDULE/. THROUGH MIDNIGHT...ONLY A FEW TENTHS OF AN INCH SNOW
ACCUMULATION EXPECTED THERE MAINLY IN THE HIGHER TERRAIN NORTH OF
THE THRUWAY. FORECAST REMAINS ON TRACK.
625 PM UPDATE...
SMALL CLUSTER OF LIGHT SNOW SHOWERS HAS CARRIED ACROSS THE ONTARIO
PENINSULA...AND NOW OVER WESTERN TO CENTRAL LAKE ONTARIO WHILE
BECOMING LAKE ENHANCED. THIS ACTIVITY EN ROUTE TO ONEIDA COUNTY
MAINLY NORTH OF THE THRUWAY 03Z-06Z TO PERHAPS YIELD A VERY LIGHT
SKIFF OF SNOW. THEN MINOR LAKE EFFECT TO CONTINUE OVERNIGHT INTO
MONDAY MORNING VIA 270 FLOW GRADUALLY VEERING 290-300...WITH
ACCUMULATIONS VERY LIGHT IF ANY /AGAIN ON ORDER OF TENTHS OF AN
INCH/. FORECAST TWEAKED FOR SMALLER DETAILS...OVERALL IN FINE
SHAPE.
PREVIOUS DISCUSSION...
SOLID LL CLD DECK ALL THE WAY BACK INTO SW ONTARIO DESPITE THE NW
FLOW OF DRIER AIR. XPCTY CONTD SLOW IMPRMT OVER NGT AS INCRSGLY
DRIER AIR MVES INTO THE AREA. HRRR AND ARW DVLP SOME LGT LE LATE
TNGT AS THE WLY DVLPS A SINGLE BAND INTO NRN ONEIDA AND PERHAPS
XTRM NRN ONONDAGA. WITH MRGNL TEMPS AND WEAK LE XPCT ONLY TRACE
AMTS. DESPITE THE COND CAA...OVRNGT TEMPS STILL WILL END UP ABV
NRML FOR THE SEASON.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
CONTD WEAK LE EVENT PSBL WITH A SOMEWHAT SHEARED WNW FLOW AND MRGNL
INSTABILITY. ISLTD LGT SNOW SHWRS PSBL OVER THE HIGHER TERRAIN MON
AS HTG ADDS A BIT OF INSTBILITY OVER THE BARE GND. NAM FCST A WEAK
SFC LOW TO DVLP OVRNGT MON WHICH REALLY JUST DISRUPTS THE BNDRY
LYR FLOW WITHOUT ENHANCING THE LE.
LTL CHG FOR TUE OTR THAN SLGTLY COLDER AIR IN PLACE AND PERHAPS A
BIT BETTER ALIGNED LL FLOW. ALSO...HINT OF A SHRT WV MAY ENHANCE
THE INSTABILITY LATE IN THE DAY. FLOW CONTS TO FAVOR ANY ACTIVITY
TO BE OVER THE NRN THIRD OF THE FCST AREA.
BEST CHANCE FOR LE WILL BE WED AS THE CONTD CAA HAS BROUGHT THE
SNDG DEEPER INTO THE SNOW GROWTH ZONE AND FLOW BECOMES BETTER
ALIGNED. WRKG AGAINST SIGNIFICANT ACCUMS WILL BE A CONSTANTLY CHGG
MEAN FLOW AS A WV PASSES...AND YET ANOTHER APRCHS KICKING ANY BAND
THAT DVLPS NORTH OF THE FCST AREA.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
2 AM UPDATE...
FOLLOWED WPC GUIDANCE. LAKE EFFECT FAR NORTH TO START WITH THEN
POSSIBLE STORMS. STILL MUCH UNCERTAINTY ON THE FRIDAY TO SUNDAY
SCENARIO. MODELS DO NOT AGREE...BUT TREND TO A BIGGER PRECIP EVENT
FOR SUNDAY AND NOT FRIDAY OR SATURDAY. WPC HAS THE HIGHEST POPS ON
SATURDAY WITH A COLD FRONT MOVING SE THROUGH THE CWA AND MOISTURE
RUNNING NE AHEAD OF IT. AS STARTED BELOW COULD BE A MIXED PRECIP
EVENT. SUNDAY STORM WILL DEPEND ON THE TRACK WITH THE EURO WELL
SOUTH AND SNOW AND THE GFS TO THE WEST AND RAIN.
PREVIOUS DISCUSSION...
THE LONG TERM PERIOD BEGINS WITH A LARGE SCALE TROF ACROSS CENTRAL
AND EASTERN CANADA. A COOL NORTHWEST FLOW WILL BRING LAKE EFFECT
SNOW SHOWERS INTO NORTHERN NY INTO THURSDAY.
A STORM SYSTEM MOVING OUT OF THE SOUTH CENTRAL UNITED STATES WILL
SPREAD PRECIPITATION INTO NY/PA FRIDAY NIGHT. THE PRECIPITATION
MAY ARRIVE AS LIGHT SNOW WITH POCKETS OF FREEZING RAIN. HOWEVER,
ONCE THE WARM AIR PUSHES THROUGH THE REGION EARLY SATURDAY,
TEMPERATURES WILL RISE INTO THE 40S AND THE PRECIPITATION WILL
CHANGE TO RAIN.
GENERALLY FOLLOWED HPC GUIDANCE WITH ADJUSTMENTS FOR LAKE EFFECT
AREAS.
&&
.AVIATION /07Z MONDAY THROUGH FRIDAY/...
1230 AM UPDATE...
MAINLY VFR CIGS AT AROUND 4K FT. WEAK LAKE EFFECT SNOW SHOWERS AND
CLOUDS. SYR AND RME MAY DROP TO MVFR CIGS AT TIMES DUE TO CLOUDS
BETWEEN NOW AND 12Z. ITH AND BGM MAY DROP TO MVFR CIGS MORE DUE TO
ELEVATION AND PROXIMITY TO CAYUGA LAKE AND ADDED MOISTURE.
WEST TO NORTHWEST WINDS AT 5 TO 10 KTS. ELM LIGHT AND VARIABLE AT
NIGHT.
OUTLOOK...
MON NGT TO WED NGT...BRIEF RESTRICTIONS POSSIBLE AT TIMES FOR
KRME/KSYR AND MAYBE KITH/KBGM...DUE TO LAKE EFFECT -SHSN.
OTHERWISE...VFR IS EXPECTED.
THU TO FRI...MVFR POSSIBLE IN SNOW WITH COLD FRONT IN NY.
AVP...VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...DGM
NEAR TERM...DGM/MDP
SHORT TERM...DGM
LONG TERM...DJP/TAC
AVIATION...TAC
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1254 AM EST MON DEC 29 2014
.SYNOPSIS...
A NORTHWEST FLOW OF COLD AIR WILL RETURN THE AREA TO MORE
SEASONABLE WEATHER THIS WEEK. AS THIS AIR CROSSES THE GREAT
LAKES IT WILL PICK UP SOME MOISTURE...SO A FEW LAKE EFFECT SNOW
SHOWERS AND FLURRIES ARE POSSIBLE...ESPECIALLY OVER CENTRAL NEW
YORK.
&&
.NEAR TERM /THROUGH TODAY/...
930 PM UPDATE...
LAKE ENHANCED SNOW SHOWERS NOW ENTERING FAR NORTHERN ONEIDA COUNTY
AS HAD BEEN ANTICIPATED /IF ANYTHING...JUST A SMIDGE AHEAD OF
SCHEDULE/. THROUGH MIDNIGHT...ONLY A FEW TENTHS OF AN INCH SNOW
ACCUMULATION EXPECTED THERE MAINLY IN THE HIGHER TERRAIN NORTH OF
THE THRUWAY. FORECAST REMAINS ON TRACK.
625 PM UPDATE...
SMALL CLUSTER OF LIGHT SNOW SHOWERS HAS CARRIED ACROSS THE ONTARIO
PENINSULA...AND NOW OVER WESTERN TO CENTRAL LAKE ONTARIO WHILE
BECOMING LAKE ENHANCED. THIS ACTIVITY EN ROUTE TO ONEIDA COUNTY
MAINLY NORTH OF THE THRUWAY 03Z-06Z TO PERHAPS YIELD A VERY LIGHT
SKIFF OF SNOW. THEN MINOR LAKE EFFECT TO CONTINUE OVERNIGHT INTO
MONDAY MORNING VIA 270 FLOW GRADUALLY VEERING 290-300...WITH
ACCUMULATIONS VERY LIGHT IF ANY /AGAIN ON ORDER OF TENTHS OF AN
INCH/. FORECAST TWEAKED FOR SMALLER DETAILS...OVERALL IN FINE
SHAPE.
PREVIOUS DISCUSSION...
SOLID LL CLD DECK ALL THE WAY BACK INTO SW ONTARIO DESPITE THE NW
FLOW OF DRIER AIR. XPCTY CONTD SLOW IMPRMT OVER NGT AS INCRSGLY
DRIER AIR MVES INTO THE AREA. HRRR AND ARW DVLP SOME LGT LE LATE
TNGT AS THE WLY DVLPS A SINGLE BAND INTO NRN ONEIDA AND PERHAPS
XTRM NRN ONONDAGA. WITH MRGNL TEMPS AND WEAK LE XPCT ONLY TRACE
AMTS. DESPITE THE COND CAA...OVRNGT TEMPS STILL WILL END UP ABV
NRML FOR THE SEASON.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY/...
CONTD WEAK LE EVENT PSBL WITH A SOMEWHAT SHEARED WNW FLOW AND MRGNL
INSTABILITY. ISLTD LGT SNOW SHWRS PSBL OVER THE HIGHER TERRAIN MON
AS HTG ADDS A BIT OF INSTBILITY OVER THE BARE GND. NAM FCST A WEAK
SFC LOW TO DVLP OVRNGT MON WHICH REALLY JUST DISRUPTS THE BNDRY
LYR FLOW WITHOUT ENHANCING THE LE.
LTL CHG FOR TUE OTR THAN SLGTLY COLDER AIR IN PLACE AND PERHAPS A
BIT BETTER ALIGNED LL FLOW. ALSO...HINT OF A SHRT WV MAY ENHANCE
THE INSTABILITY LATE IN THE DAY. FLOW CONTS TO FAVOR ANY ACTIVITY
TO BE OVER THE NRN THIRD OF THE FCST AREA.
BEST CHANCE FOR LE WILL BE WED AS THE CONTD CAA HAS BROUGHT THE
SNDG DEEPER INTO THE SNOW GROWTH ZONE AND FLOW BECOMES BETTER
ALIGNED. WRKG AGAINST SIGNIFICANT ACCUMS WILL BE A CONSTANTLY CHGG
MEAN FLOW AS A WV PASSES...AND YET ANOTHER APRCHS KICKING ANY BAND
THAT DVLPS NORTH OF THE FCST AREA.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
THE LONG TERM PERIOD BEGINS WITH A LARGE SCALE TROF ACROSS CENTRAL
AND EASTERN CANADA. A COOL NORTHWEST FLOW WILL BRING LAKE EFFECT
SNOW SHOWERS INTO NORTHERN NY INTO THURSDAY.
A STORM SYSTEM MOVING OUT OF THE SOUTH CENTRAL UNITED STATES WILL
SPREAD PRECIPITATION INTO NY/PA FRIDAY NIGHT. THE PRECIPITATION
MAY ARRIVE AS LIGHT SNOW WITH POCKETS OF FREEZING RAIN. HOWEVER,
ONCE THE WARM AIR PUSHES THROUGH THE REGION EARLY SATURDAY,
TEMPERATURES WILL RISE INTO THE 40S AND THE PRECIPITATION WILL
CHANGE TO RAIN.
GENERALLY FOLLOWED HPC GUIDANCE WITH ADJUSTMENTS FOR LAKE EFFECT
AREAS.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
1230 AM UPDATE...
MAINLY VFR CIGS AT AROUND 4K FT. WEAK LAKE EFFECT SNOW SHOWERS AND
CLOUDS. SYR AND RME MAY DROP TO MVFR CIGS AT TIMES DUE TO CLOUDS
BETWEEN NOW AND 12Z. ITH AND BGM MAY DROP TO MVFR CIGS MORE DUE TO
ELEVATION AND PROXIMITY TO CAYUGA LAKE AND ADDED MOISTURE.
WEST TO NORTHWEST WINDS AT 5 TO 10 KTS. ELM LIGHT AND VARIABLE AT
NIGHT.
OUTLOOK...
MON NGT TO WED NGT...BRIEF RESTRICTIONS POSSIBLE AT TIMES FOR
KRME/KSYR AND MAYBE KITH/KBGM...DUE TO LAKE EFFECT -SHSN.
OTHERWISE...VFR IS EXPECTED.
THU TO FRI...MVFR POSSIBLE IN SNOW WITH COLD FRONT IN NY.
AVP...VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...DGM
NEAR TERM...DGM/MDP
SHORT TERM...DGM
LONG TERM...DJP
AVIATION...TAC
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
1231 PM EST MON DEC 29 2014
.SYNOPSIS...
A COLD FRONT WILL DROP SOUTH ACROSS THE AREA TODAY. BEHIND THE
FRONT...HIGH PRESSURE WILL BUILD ACROSS THE NATIONS MID SECTION
AND EXTEND INTO THE GREAT LAKES AND OHIO VALLEY THROUGH MID WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATE FOR MINOR CHANGES. LATEST HRRR CONTINUE TO SHOW SOME SNOW
SHOWERS ACROSS NW PA THIS AFTERNOON. WILL CONTINUE WITH A 20 POP.
ORIGINAL...HIGH CLOUDS DRIFTING EAST OVERNIGHT HOWEVER SATELLITE
SHOWS STRATUS DEVELOPING ACROSS THE CENTRAL AND EAST LAKESHORE
COUNTIES AND A LARGE AREA OF STRATUS ACROSS LOWER MI AND NORTH OF
LAKE ERIE DRIFTING SOUTH. ELSEWHERE SKIES MOSTLY CLEAR. FOR THE
EARLY MORNING AM EXPECTING STRATUS TO CONTINUE TO EXPAND AS LOW
LEVEL LOW COMES OFF THE LAKE. THE STRATUS ACROSS LOWER MI AND
CANADA NORTH OF LAKE ERIE HAS TENDED TO DISSIPATE ON THE SOUTHERN
SIDE SLOWING ITS PROGRESSION. FOLLOWING THE NAM 925MB RH ONE WOULD
EXPECT THE STRATUS TO EITHER MOVE IN FROM THE NORTHWEST OR DEVELOP
ACROSS THE AREA HOWEVER THERE ARE PLENTY OF HOLES AND WITH DRY AIR
ABOVE...ANY MIXING WOULD TEND TO ALLOW MORE HOLES TO DEVELOP. FOR
NOW AWAY FROM THE LAKE...WILL BEGIN WITH PC AND THEN TRANSITION TO
MC OR PS. GUIDANCE HIGHS IN THE LOW TO MID 30S LOOK FINE WITH ONLY
MINOR ADJUSTMENTS.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY NIGHT/...
HIGH PRESSURE WILL CONTINUE TO NOSE INTO THE AREA TONIGHT THROUGH
WEDNESDAY AS IT DROPS THROUGH THE CENTRAL PLAINS. GIVEN ITS TRACK
HOWEVER COLD ADVECTION WILL CONTINUE THROUGH THE PERIOD WITH BOTH
THE NAM AND GFS SHOWING -16 TO -18C BY WEDNESDAY 12Z. OUTSIDE OF
ANY LAKE EFFECT THE AIRMASS REMAINS FAIRLY DRY THROUGH THE SHORT
TERM PERIOD. GIVEN THE TEMP FALL HOWEVER WILL CONTINUE WITH CHANCE
POPS ALL ALONG THE LAKESHORE COUNTIES FROM LORAIN CO EAST
BEGINNING TUESDAY AFTERNOON...INCREASING TO LIKELY ASHTABULA ERIE
CRAWFORD TUESDAY NIGHT AS LAKE-850MB TEMP DIFFERENCE BECOMES
ENOUGH FOR MODERATE INSTABILITY AS SHOWN ON BUFKIT KERI FORECAST
SOUNDING. WILL CONTINUE WITH CHANCE POPS WEDNESDAY. WINDS BACK
TO SOUTHWEST WEDNESDAY NIGHT TAKING ANY BANDS OFFSHORE. THURSDAY
NIGHT THE GFS SHOWS ANOTHER TROF DROPPING SOUTH ACROSS THE LAKES
BRINGING MOISTURE TO THE AREA. WILL BRING CHANCE POPS BACK TO THE
NORTHERN COUNTIES WITH HIGHEST POPS IN THE SNOWBELT. TEMPS
GENERALLY BELOW NORMAL.
&&
.LONG TERM /FRIDAY THROUGH SUNDAY/...
LONG RANGE MODELS HAD SOME DIFFERENCES TO THEIR SOLUTIONS ON
SATURDAY WITH THE EUROPEAN BEING THE DRIEST COMPARED TO THE WET GFS
MODEL. LATEST RUN OF THE EUROPEAN AT 00Z IS NOW INDICATING A WETTER
SOLUTION IN LINE WITH THE GFS SO WILL BE LEANING IN THE DIRECTION OF
SPREADING PRECIPITATION INTO THE REGION DURING THE DAY SATURDAY. I
GUESS UNTIL I SEE SOME CONSISTENCY IN THE MODELS FOR WARMING THINGS
UP ON SATURDAY...I WILL NOT GET TOO CRAZY IN RAISING TEMPERATURES
FOR HIGHS. LATEST GUIDANCE SUGGESTS A FAIRLY BRISK SOUTH TO
SOUTHWESTERLY FLOW ON SATURDAY INDICATING TEMPERATURES WILL BE MUCH
WARMER THAN WE HAVE CURRENTLY FORECAST. SO...I GUESS I WOULD EXPECT
TEMPERATURES TRENDING UPWARD OVER THE NEXT FEW DAYS IF MODELS ARE
PERSISTENT.
ONCE SURFACE LOW GOES BY ON SUNDAY...COLD AIR ADVECTION WILL RETURN
TO THE REGION. THIS WILL LIKELY SET UP SOME LAKE EFFECT SNOW SHOWERS
BY SUNDAY NIGHT INTO MONDAY. DEPENDING ON THE TIMING OF THE LOW
PASSAGE...SOME COULD BEGIN AS EARLY AS LATE SUNDAY AFTERNOON.
COLD AIR ADVECTION LOOKS LIKE IT WILL BE A GLANCING BLOW AS HIGH
PRESSURE BUILDS SOUTHEAST ACROSS THE GREAT LAKES BY THE MIDDLE OF
THE WEEK.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
WEAK COLD FRONT CROSSING THE AREA FOR THE AFTERNOON HOURS. HIGH
PRESSURE IN ITS WAKE. FRONT MAY GENERATE A FLURRY IN NW PA WITH
LITTLE ADDITIONAL AVIATION IMPACT BEYOND THAT OF THE CURRENT MVFR
CEILINGS TODAY. CEILINGS WILL REMAIN MVFR UNTIL LATE IN THE
AFTERNOON WHEN THEY HAVE A CHANCE AT IMPROVING TO VFR. MVFR
CEILINGS REDEVELOP OVERNIGHT. LIGHT NORTH WINDS 10 KNOTS OR LESS.
.OUTLOOK...AREAS OF NON VFR TUESDAY AFTERNOON THROUGH WEDNESDAY
AND THEN AGAIN THURSDAY NIGHT THROUGH FRIDAY NIGHT.
&&
.MARINE...
LAKE IS EXPECTED TO BE FAIRLY QUIET TODAY AND TONIGHT BUT WINDS ARE
EXPECTED TO PICK UP SPEED BY TUESDAY AFTERNOON INTO WEDNESDAY. FLOW
WILL GRADUALLY SHIFT AROUND TO THE SOUTHWEST BY WEDNESDAY NIGHT AND
INCREASE EVEN FURTHER. I WOULD IMAGINE THAT AT SOME POINT WE ARE
GOING TO NEED A SMALL CRAFT ADVISORY TUESDAY AND POSSIBLY GALES BY
WEDNESDAY NIGHT. SO WILL INCLUDE A MENTION OF GALE POTENTIAL IN THE
HAZARDOUS WEATHER OUTLOOK. WINDS STAY PRETTY GUSTY OUT OF THE WEST
SOUTHWEST INTO THURSDAY WHEN THEY EVENTUALLY DIMINISH.
UNFORTUNATELY...SMALL CRAFT ADVISORIES WILL LIKELY BE NEEDED GOING
INTO FRIDAY AS WINDS DO NOT DIMINISH ENOUGH.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...TK
NEAR TERM...TK/KUBINA
SHORT TERM...TK
LONG TERM...LOMBARDY
AVIATION...OUDEMAN
MARINE...LOMBARDY
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
944 AM EST MON DEC 29 2014
.SYNOPSIS...
A COLD FRONT WILL DROP SOUTH ACROSS THE AREA TODAY. BEHIND THE
FRONT...HIGH PRESSURE WILL BUILD ACROSS THE NATIONS MID SECTION
AND EXTEND INTO THE GREAT LAKES AND OHIO VALLEY THROUGH MID WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATE FOR MINOR CHANGES. LATEST HRRR CONTINUE TO SHOW SOME SNOW
SHOWERS ACROSS NW PA THIS AFTERNOON. WILL CONTINUE WITH A 20 POP.
ORIGINAL...HIGH CLOUDS DRIFTING EAST OVERNIGHT HOWEVER SATELLITE
SHOWS STRATUS DEVELOPING ACROSS THE CENTRAL AND EAST LAKESHORE
COUNTIES AND A LARGE AREA OF STRATUS ACROSS LOWER MI AND NORTH OF
LAKE ERIE DRIFTING SOUTH. ELSEWHERE SKIES MOSTLY CLEAR. FOR THE
EARLY MORNING AM EXPECTING STRATUS TO CONTINUE TO EXPAND AS LOW
LEVEL LOW COMES OFF THE LAKE. THE STRATUS ACROSS LOWER MI AND
CANADA NORTH OF LAKE ERIE HAS TENDED TO DISSIPATE ON THE SOUTHERN
SIDE SLOWING ITS PROGRESSION. FOLLOWING THE NAM 925MB RH ONE WOULD
EXPECT THE STRATUS TO EITHER MOVE IN FROM THE NORTHWEST OR DEVELOP
ACROSS THE AREA HOWEVER THERE ARE PLENTY OF HOLES AND WITH DRY AIR
ABOVE...ANY MIXING WOULD TEND TO ALLOW MORE HOLES TO DEVELOP. FOR
NOW AWAY FROM THE LAKE...WILL BEGIN WITH PC AND THEN TRANSITION TO
MC OR PS. GUIDANCE HIGHS IN THE LOW TO MID 30S LOOK FINE WITH ONLY
MINOR ADJUSTMENTS.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY NIGHT/...
HIGH PRESSURE WILL CONTINUE TO NOSE INTO THE AREA TONIGHT THROUGH
WEDNESDAY AS IT DROPS THROUGH THE CENTRAL PLAINS. GIVEN ITS TRACK
HOWEVER COLD ADVECTION WILL CONTINUE THROUGH THE PERIOD WITH BOTH
THE NAM AND GFS SHOWING -16 TO -18C BY WEDNESDAY 12Z. OUTSIDE OF
ANY LAKE EFFECT THE AIRMASS REMAINS FAIRLY DRY THROUGH THE SHORT
TERM PERIOD. GIVEN THE TEMP FALL HOWEVER WILL CONTINUE WITH CHANCE
POPS ALL ALONG THE LAKESHORE COUNTIES FROM LORAIN CO EAST
BEGINNING TUESDAY AFTERNOON...INCREASING TO LIKELY ASHTABULA ERIE
CRAWFORD TUESDAY NIGHT AS LAKE-850MB TEMP DIFFERENCE BECOMES
ENOUGH FOR MODERATE INSTABILITY AS SHOWN ON BUFKIT KERI FORECAST
SOUNDING. WILL CONTINUE WITH CHANCE POPS WEDNESDAY. WINDS BACK
TO SOUTHWEST WEDNESDAY NIGHT TAKING ANY BANDS OFFSHORE. THURSDAY
NIGHT THE GFS SHOWS ANOTHER TROF DROPPING SOUTH ACROSS THE LAKES
BRINGING MOISTURE TO THE AREA. WILL BRING CHANCE POPS BACK TO THE
NORTHERN COUNTIES WITH HIGHEST POPS IN THE SNOWBELT. TEMPS
GENERALLY BELOW NORMAL.
&&
.LONG TERM /FRIDAY THROUGH SUNDAY/...
LONG RANGE MODELS HAD SOME DIFFERENCES TO THEIR SOLUTIONS ON
SATURDAY WITH THE EUROPEAN BEING THE DRIEST COMPARED TO THE WET GFS
MODEL. LATEST RUN OF THE EUROPEAN AT 00Z IS NOW INDICATING A WETTER
SOLUTION IN LINE WITH THE GFS SO WILL BE LEANING IN THE DIRECTION OF
SPREADING PRECIPITATION INTO THE REGION DURING THE DAY SATURDAY. I
GUESS UNTIL I SEE SOME CONSISTENCY IN THE MODELS FOR WARMING THINGS
UP ON SATURDAY...I WILL NOT GET TOO CRAZY IN RAISING TEMPERATURES
FOR HIGHS. LATEST GUIDANCE SUGGESTS A FAIRLY BRISK SOUTH TO
SOUTHWESTERLY FLOW ON SATURDAY INDICATING TEMPERATURES WILL BE MUCH
WARMER THAN WE HAVE CURRENTLY FORECAST. SO...I GUESS I WOULD EXPECT
TEMPERATURES TRENDING UPWARD OVER THE NEXT FEW DAYS IF MODELS ARE
PERSISTENT.
ONCE SURFACE LOW GOES BY ON SUNDAY...COLD AIR ADVECTION WILL RETURN
TO THE REGION. THIS WILL LIKELY SET UP SOME LAKE EFFECT SNOW SHOWERS
BY SUNDAY NIGHT INTO MONDAY. DEPENDING ON THE TIMING OF THE LOW
PASSAGE...SOME COULD BEGIN AS EARLY AS LATE SUNDAY AFTERNOON.
COLD AIR ADVECTION LOOKS LIKE IT WILL BE A GLANCING BLOW AS HIGH
PRESSURE BUILDS SOUTHEAST ACROSS THE GREAT LAKES BY THE MIDDLE OF
THE WEEK.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
STRATUS BETWEEN 2500 AND 3500 FEET CONTINUES TO DEVELOP ACROSS THE
CENTRAL AND EAST LAKESHORE COUNTIES AS LOW LEVEL MOISTURE REMAINS
TRAPPED ACROSS THE AREA. EXPECTING THIS CLOUD COVER TO GRADUALLY
DISSIPATE THIS AFTERNOON INTO THE EVENING HOURS. HOWEVER...SOME
HIGH CLOUDS WILL SPREAD INTO THE REGION THIS AFTERNOON AND EVENING
SO NO REAL LONG STRETCH OF CLEAR SKIES EXPECTED TODAY. WINDS
SHOULD BE LIGHT NORTH TO NORTHWEST BECOMING LIGHT AND VARIABLE
OVERNIGHT.
.OUTLOOK...AREAS OF NON VFR CEILINGS LATE MONDAY NIGHT THROUGH
WEDNESDAY.
&&
.MARINE...
LAKE IS EXPECTED TO BE FAIRLY QUIET TODAY AND TONIGHT BUT WINDS ARE
EXPECTED TO PICK UP SPEED BY TUESDAY AFTERNOON INTO WEDNESDAY. FLOW
WILL GRADUALLY SHIFT AROUND TO THE SOUTHWEST BY WEDNESDAY NIGHT AND
INCREASE EVEN FURTHER. I WOULD IMAGINE THAT AT SOME POINT WE ARE
GOING TO NEED A SMALL CRAFT ADVISORY TUESDAY AND POSSIBLY GALES BY
WEDNESDAY NIGHT. SO WILL INCLUDE A MENTION OF GALE POTENTIAL IN THE
HAZARDOUS WEATHER OUTLOOK. WINDS STAY PRETTY GUSTY OUT OF THE WEST
SOUTHWEST INTO THURSDAY WHEN THEY EVENTUALLY DIMINISH.
UNFORTUNATELY...SMALL CRAFT ADVISORIES WILL LIKELY BE NEEDED GOING
INTO FRIDAY AS WINDS DO NOT DIMINISH ENOUGH.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...TK
NEAR TERM...TK/KUBINA
SHORT TERM...TK
LONG TERM...LOMBARDY
AVIATION...LOMBARDY
MARINE...LOMBARDY
AREA FORECAST DISCUSSION...UPDATED
NWS NORMAN OK
1038 AM CST MON DEC 29 2014
.UPDATE...
TWEAKED SKY COVER AND TEMPERATURES THIS AFTERNOON ACROSS
THE AREA.
&&
.DISCUSSION...
TODAY MAY BE THE WARMEST DAY OF THE WEEK IN MANY LOCATIONS.
MUCH COLDER AIR WILL ARRIVE TONIGHT.
LATEST WEATHER MAP SHOWED A WEAK SURFACE LOW OVER FAR WESTERN
NORTH TEXAS NEAR KNOX CITY. LOW LEVEL MOISTURE IS INCREASING
NORTH AND EAST OF THIS LOW...WHICH WILL ALLOW FOR CLOUDS TO
DEVELOP THIS AFTERNOON IN MANY AREAS. THUS...TWEAKED SKY COVER
UPWARDS THIS AFTERNOON NORTH AND EAST OF A HOBART TO MARIETTA
LINE. LATEST HRRR RUNS HAVE A GREAT HANDLE ON THIS. MOISTURE
APPEARS TO BE TOO SHALLOW FOR PRECIPITATION...AT LEAST THROUGH
6 PM TODAY.
HIGHS TODAY WILL BE TRICKY WITH INCREASING CLOUD COVER.
GENERALLY TWEAKED THEM DOWNWARD 1 TO 3 DEGREES FROM JUST EAST
OF OKLAHOMA CITY TO DURANT...AND UPWARD 1 TO 3 DEGREES OVER
NORTHERN OKLAHOMA WITH A SLOWER ARRIVAL OF THE ARCTIC FRONT.
PRODUCTS HAVE BEEN UPDATED.
MBS
&&
.PREV DISCUSSION... /ISSUED 534 AM CST MON DEC 29 2014/
AVIATION...
A COLD FRONT IS EXPECTED TO MOVE IN THIS AFTERNOON...BRINGING
BREEZY NORTH WINDS BEHIND IT. MVFR CEILINGS MAY MOVE INTO CENTRAL
OKLAHOMA AROUND NOON...BUT BAND IS EXPECTED TO BE FAIRLY NARROW SO
CONFIDENCE IS LOW THAT IT WILL AFFECT KOKC AND KOUN. LATE TONIGHT
INTO TOMORROW MORNING MAY SEE SOME LOW CLOUDS IN THE MVFR RANGE.
PREV DISCUSSION... /ISSUED 402 AM CST MON DEC 29 2014/
DISCUSSION...
SPECIAL WEATHER STATEMENT/WINTER STORM OUTLOOK WILL BE ISSUED
SHORTLY.
OVERALL...LITTLE CHANGE TO GOING FORECAST WITH SEVERAL EPISODES OF
IMPACTING WINTER WEATHER EXPECTED THE NEXT SEVERAL DAYS.
CONFIDENCE IS INCREASING THAT ADVISORIES WILL LIKELY BE ISSUED
MID-LATE WEEK AND WARNINGS CANNOT BE RULED OUT. FIRST ORDER WILL
BE INTRUSION OF ARCTIC AIR AND LOW WIND CHILL VALUES TONIGHT
THROUGH WEDNESDAY. COLDEST READINGS...TEENS AND SINGLE DIGITS
BELOW ZERO...WILL BE POSSIBLE OVER AT LEAST NORTHWEST HALF OF
OKLAHOMA. A WIND CHILL ADVISORY MAY BE ISSUED LATER TODAY OR
TONIGHT. ALSO...LIGHT SNOW WILL BE POSSIBLE ACROSS FAR WESTERN
OKLAHOMA TUESDAY AND TUESDAY NIGHT WITH UPSLOPE EVENT EXPECTED TO
UNFOLD BEHIND ARCTIC FRONT. AROUND AN INCH OF SNOW POSSIBLE ACROSS
FAR NORTHWEST AND WEST-CENTRAL OKLAHOMA.
IN THE WAKE OF THE SUBZERO WIND CHILLS AND SCATTERED SNOW ACROSS
FAR WESTERN OKLAHOMA...ATTENTION WILL TURN TOWARD THURSDAY THROUGH
EARLY FRIDAY AS FREEZING RAIN AND SLEET EVENT UNFOLDS. WE AGREE
MOST STRONGLY WITH PARALLEL-GFS (P-GFS) AND ECM WITH OVERALL ARE
IN REASONABLE AGREEMENT LATE WEEK INTO WEEKEND. FOR THE THURSDAY
INTO FRIDAY SCENARIO...OPERATIONAL GFS APPEARS TO ERODE BOUNDARY
LAYER COLD AIR MUCH TOO QUICKLY. ECM/P-GFS DRIER AND SLOWER TO
ERODE COLD AIR WITH WEAK WINDS AND PERSISTENT E/W LOW LEVEL RIDGE
ENTRENCHED OVER REGION. THEY MAY BE TOO FAST. FORECAST SOUNDINGS
STILL POINT TO DOMINANT PRECIP TYPE OF SLEET WITH RAIN AND
FREEZING RAIN AT TIMES. SNOW APPEARS TO BE A NON-ISSUE DURING THIS
TIME PERIOD. HEAVIEST AMOUNTS ARE CONSISTENT IN THE MODELS WHICH
IS OVER SOUTH-CENTRAL INTO SOUTHEAST PARTS OF OKLAHOMA. OVERALL...
THE ECM AND P-GFS WHICH WE ARE BASING FORECAST ON HAS MUCH LOWER
QPF THAN THE OPERATIONAL GFS. DURING THE DAY FRIDAY...TEMPS SHOULD
WARM JUST ENOUGH FOR RAIN OVER NORTH TEXAS AND AT LEAST THE
SOUTHERN HALF TO THREE-QUARTERS OF OKLAHOMA. SOME LIGHT SLEET OR
FREEZING RAIN STILL LOOKS POSSIBLE OVER NORTHERN OKLAHOMA.
AS UPPER SYSTEM PULLS OUT SATURDAY-SUNDAY...MUCH OF THE AREA WILL
LIKELY BE IN WARM SECTOR AND MAINLY LIQUID. TRACK OF UPPER LOW
STILL A BIT UNCERTAIN BUT P-GFS IS A GOOD COMPROMISE BETWEEN THE
MUCH SLOWER AND FARTHER SOUTH ECM...AND THE FASTER FARTHER NORTH
GFS. MOD-HEAVY SNOW CHANCES ON NORTH/WEST PERIPHERY OF MID LEVEL
CYCLONE EXPECTED TO BE CONFINED TO NORTHERN OKLAHOMA AND AREAS
NORTH.
ANOTHER SHOT OF VERY COLD AIR LOOKS LIKELY AFTER THIS STORM SYSTEM
SHIFTS EAST. GFS AND P-GFS MUCH COLDER THAN ECM WITH THIS PART OF
THE FORECAST BEYOND THIS PACKAGE.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 43 23 31 13 / 0 10 10 10
HOBART OK 44 21 29 11 / 0 0 20 20
WICHITA FALLS TX 53 26 36 17 / 0 10 10 10
GAGE OK 38 12 18 3 / 0 20 30 30
PONCA CITY OK 42 19 25 5 / 0 10 10 10
DURANT OK 42 29 43 23 / 0 10 0 0
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
03/17
AREA FORECAST DISCUSSION
NWS TULSA OK
1124 PM CST SUN DEC 28 2014
.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG.
AREA OF LOW CLOUDS ACROSS CENTRAL AR AND FAR SERN OK CONTINUED TO
SLOWLY EXPAND WESTWARD AS OF 05Z. CARRIED SOME MVFR CIGS FOR A FEW
HOURS LATER TONIGHT AT MLC. MVFR VSBYS IN FOG ARE PROBABLE ACROSS
NWRN AR SITES 09-15Z AND POSSIBLE TUL/RVS...THE LATTER OF WHICH
ARE IN YESTERDAYS LIGHT SNOW FIELD THAT MELTED AWAY TODAY.
OTHERWISE...EXPECT VFR WITH VARIABLE HIGH CLOUDS. STRONG COLD
FRONT PUSHES THROUGH NERN OK SITES BY END OF PERIOD WITH MID
CLOUDS THICKENING AT THAT TIME.
&&
.PREV DISCUSSION... /ISSUED 908 PM CST SUN DEC 28 2014/
DISCUSSION...
THE DIFFERENCE FIELD BETWEEN THE 11.0 MICRON AND 3.9 MICRON
INFRA-RED SATELLITE DATA SHOWS LOW CLOUDS HOLDING OVER THE
SOUTHEAST TIP OF OKLAHOMA THIS EVENING. AS THE LOW-LEVEL FLOW
BECOMES LIGHT SOUTHEASTERLY THE CLOUDS SHOULD HAVE A TENDENCY TO
EXPAND NORTHWEST SOME AND HAVE SHOWN AN INCREASE IN CLOUDS LATER
TONIGHT IN FAR SOUTHEAST OKLAHOMA.
ALSO INTERESTING IS THE CURRENT SURFACE RELATIVE HUMIDITY FIELD
SHOWING READINGS AT JUST BEFORE 03Z IN THE UPPER 90S AT A FEW
MESONET SITES IN SOUTHEAST OKLAHOMA AND IN THE MID 90S OVER THE
OLD NARROW SNOW FIELD IN NORTHEAST OKLAHOMA. WITH LIGHT MOISTURE
ADVECTION DEVELOPING IN THE SOUTHEASTERLY SURFACE FLOW... THESE
AREAS WHERE THE HUMIDITY IS ALREADY HIGH WILL BE FAVORED FOR
PATCHY DENSE FOG FORMATION. NOT OVERLY CONFIDENT ABOUT THE
EVOLUTION OR COVERAGE...BUT IT IS WORTH SHOWING IN THE FORECAST
TEXT AND GRIDS. THE HRRR IS LIKELY OVERLY DRAMATIC...BUT IT SHOWS
VERY INTERESTING MESOSCALE TEMPERATURE...WIND AND HUMIDITY
EVOLUTIONS OVER THE OLD SNOW FIELD...WITH FOG ADVECTING NORTHWEST
SLOWLY LATER TONIGHT FROM THE OLD SNOW COVERED AREA.
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
SHORT TERM...08
AVIATION...69
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
1120 AM CST MON DEC 29 2014
.DISCUSSION...
UPDATED FOR 18Z AVIATION DISCUSSION.
&&
.PREV DISCUSSION... /ISSUED 1032 AM CST MON DEC 29 2014/
UPDATE...
AS OF 10AM...TEMPERATURES ARE GENERALLY IN THE 30S ACROSS THE
ENTIRE FA THIS MORNING. CLOUD COVER CONTINUES TO HANG TOUGH AS
NORTHEAST WINDS KEEP THE MOISTURE IN PLACE. NOT MUCH WARMING IS
ANTICIPATED FOR THE REST OF THE DAY DUE TO THIS. HIGHS TODAY WILL
TOP OUT AROUND 40 DEGREES IN THE NORTH...WITH LOW TO MID 40S TO
THE SOUTH.
QUICK UPDATE TO REMOVE LIGHT PRECIP IN GRIDS...ADJUST
CLOUD COVER...AND LOWER TEMPERATURES A COUPLE OF DEGREES.
AC3
&&
.PREV DISCUSSION... /ISSUED 452 AM CST MON DEC 29 2014/
DISCUSSION...
EARLY THIS MORNING...SATELLITE SHOWED THAT LOW CLOUDS COVERED THE
MIDSOUTH. ANY CLEARING HAS STALLED AND THE LOW CLOUDS WERE EXPANDING
IN COVERAGE. TEMPERATURES WERE MOSTLY IN THE 30S EXCEPT FOR LOWER
40S ACROSS PORTIONS OF NORTHEAST MS. WINDS WERE NORTHERLY ABOUT 5 TO
10 MPH. PATCHY LIGHT RAIN LINGERED FROM PORTIONS OF SOUTHWEST TN
INTO NORTH MS.
A STRONG SURFACE HIGH PRESSURE OF ABOUT 1058 MB WILL EXTEND FROM
SOUTHWEST CANADA TO THE MIDSOUTH TODAY. LOW CLOUDS WILL SLOWLY
DECREASE FROM THE WEST ACROSS PORTIONS OF NORTHEAST AR...BUT LOW
CLOUDS WILL PERSIST EAST OF THE MS RIVER ALL DAY. IN ADDITION...HIGH
LEVEL CLOUDS WILL SPREAD IN FROM THE WEST. TEMPERATURES WILL BE HELD
DOWN BY THE CLOUDS AND WILL BE BELOW NORMAL. BASED ON THE HRRR AND
NAM...KEPT IN AREAS OF DRIZZLE AND A SLIGHT CHANCE OF RAIN FROM
SOUTHWEST TN ALONG THE TN RIVER INTO PORTIONS OF NORTHEAST MS EARLY
THIS MORNING.
FOR TONIGHT...DID NOT CLEAR THE SKIES QUITE AS FAST AS SOME OF THE
GUIDANCE INDICATES WITH 925 MB WINDS FROM THE NORTHEAST HELPING TO
HOLD IN THE LOW CLOUDS ESPECIALLY EAST OF THE MS RIVER.
OTHERWISE...COLD HIGH PRESSURE WILL EXTEND INTO THE MIDSOUTH FROM
THE NORTH WITH PRECIPITATION FREE CONDITIONS.
SUNSHINE WILL RETURN TO THE MIDSOUTH TUESDAY AS THE STRONG SURFACE
HIGH PRESSURE MOVES INTO THE NORTHERN PLAINS. HIGH TEMPERATURES WILL
REMAIN BELOW NORMAL TUESDAY.
FOR WEDNESDAY...A SURFACE HIGH OF 1040 MB IS FORECAST TO BE CENTERED
OVER OK AND WILL DOMINATE MIDSOUTH WEATHER. SKIES WILL BE MOSTLY
SUNNY BUT IT WILL BE COLD.
WEDNESDAY AND THURSDAY MORNINGS WILL SEE LOW TEMPERATURES DIP INTO
THE 20S AREAWIDE WITH POSSIBLY SOME UPPER TEENS ACROSS THE EXTREME
NORTHERN LOCATIONS.
NEW YEARS DAY WILL CONTINUE COLD WITH INCREASING CLOUDS FROM THE
WEST DURING THE DAY. THE BLENDED GUIDANCE INDICATES A SLIGHT CHANCE
OF RAIN SPREADING INTO PORTIONS OF EAST CENTRAL AR AND NORTH MS
BY LATE AFTERNOON AS OVERRUNNING DEVELOPS.
THE OVERRUNNING PATTERN WILL STRENGTHEN THURSDAY NIGHT WITH A WARM
FRONT ALONG THE GULF COAST. A CLOSED UPPER LEVEL LOW OVER THE
SOUTHWESTERN UNITED STATES WILL MOVE SLOWLY EASTWARD. RAIN IS
FORECAST TO SPREAD ACROSS THE MIDSOUTH. A WINTRY MIXTURE OF
PRECIPITATION CONSISTING OF SLEET...RAIN...AND POSSIBLY FREEZING
RAIN IS EXPECTED THURSDAY NIGHT INTO FRIDAY MORNING ACROSS PORTIONS
OF NORTHEAST ARKANSAS...THE MISSOURI BOOTHEEL...INTO PORTIONS OF
WEST TENNESSEE. THE AFFECTED AREA IS MAINLY ALONG AND NORTH OF A
LINE FROM HARRISBURG ARKANSAS TO COVINGTON TENNESSEE TO SAVANNAH
TENNESSEE. AT THIS TIME...ANY ACCUMULATIONS ARE EXPECTED TO BE
LIGHT. THE PRECIPITATION IS EXPECTED TO CHANGE TO ALL RAIN BY MID-
MORNING FRIDAY. BRIEF SLEET MAY OCCUR JUST TO THE SOUTH OF THIS AREA
THURSDAY NIGHT BEFORE CHANGING TO RAIN WITH TEMPERATURES ABOVE
FREEZING.
FRIDAY INTO SATURDAY LOOK VERY WET FOR THE MIDSOUTH. THE UPPER LEVEL
LOW WILL SLOWLY APPROACH FROM THE WEST WITH THE WARM FRONT TO THE
SOUTH PUSHING ONLY SLOWLY NORTHWARD. MODELS DIFFER ON THE
DEVELOPMENT OF A SURFACE LOW ALONG THE FRONT. PRECIPITABLE WATER WILL
BE ON THE INCREASE WITH VALUES REACHING GREATER THAN 1.5 INCHES
ACROSS PORTIONS OF THE REGION BY FRIDAY NIGHT / SATURDAY. ELEVATED
INSTABILITY WILL ALSO INCREASE AS THE CLOSED UPPER LOW AND SOUTHWARD
EXTENDING UPPER LEVEL TROUGH APPROACHES. SCATTERED THUNDERSTORMS CAN
BE EXPECTED BY FRIDAY NIGHT AND CONTINUING INTO SATURDAY / SATURDAY
NIGHT. RAIN MAY BE LOCALLY HEAVY...HELD OFF MENTIONING THIS THREAT
IN THE HAZARDOUS WEATHER OUTLOOK FOR NOW UNTIL CONFIDENCE INCREASES.
IT IS POSSIBLE THUNDERSTORMS TO OUR SOUTH COULD CUT US OFF FROM THE
GREATER MOISTURE AND RAINFALL. THE UPPER LEVEL TROUGH / ASSOCIATED
COLD FRONT IS FORECAST THROUGH THE REGION SATURDAY NIGHT WITH A
LINGERING CHANCE OF RAIN SUNDAY.
JCL
&&
.AVIATION...
18Z TAF CYCLE
IT APPEARS THAT MVFR CIGS...WITH INITIAL IFR CONDITIONS AT
TUP...WILL CONTINUE THROUGH MOST OF THIS TAF PERIOD. THE BEST
POSSIBILITY FOR VFR WEATHER WILL BE AT JBR AND MKL. NORTHEAST
WINDS AT 6-8 KTS WILL INCREASE WITH A FEW GUSTS LATE.
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
1032 AM CST MON DEC 29 2014
.UPDATE...
AS OF 10AM...TEMPERATURES ARE GENERALLY IN THE 30S ACROSS THE
ENTIRE FA THIS MORNING. CLOUD COVER CONTINUES TO HANG TOUGH AS
NORTHEAST WINDS KEEP THE MOISTURE IN PLACE. NOT MUCH WARMING IS
ANTICIPATED FOR THE REST OF THE DAY DUE TO THIS. HIGHS TODAY WILL
TOP OUT AROUND 40 DEGREES IN THE NORTH...WITH LOW TO MID 40S TO
THE SOUTH.
QUICK UPDATE TO REMOVE LIGHT PRECIP IN GRIDS...ADJUST
CLOUD COVER...AND LOWER TEMPERATURES A COUPLE OF DEGREES.
AC3
&&
.PREV DISCUSSION... /ISSUED 452 AM CST MON DEC 29 2014/
DISCUSSION...
EARLY THIS MORNING...SATELLITE SHOWED THAT LOW CLOUDS COVERED THE
MIDSOUTH. ANY CLEARING HAS STALLED AND THE LOW CLOUDS WERE EXPANDING
IN COVERAGE. TEMPERATURES WERE MOSTLY IN THE 30S EXCEPT FOR LOWER
40S ACROSS PORTIONS OF NORTHEAST MS. WINDS WERE NORTHERLY ABOUT 5 TO
10 MPH. PATCHY LIGHT RAIN LINGERED FROM PORTIONS OF SOUTHWEST TN
INTO NORTH MS.
A STRONG SURFACE HIGH PRESSURE OF ABOUT 1058 MB WILL EXTEND FROM
SOUTHWEST CANADA TO THE MIDSOUTH TODAY. LOW CLOUDS WILL SLOWLY
DECREASE FROM THE WEST ACROSS PORTIONS OF NORTHEAST AR...BUT LOW
CLOUDS WILL PERSIST EAST OF THE MS RIVER ALL DAY. IN ADDITION...HIGH
LEVEL CLOUDS WILL SPREAD IN FROM THE WEST. TEMPERATURES WILL BE HELD
DOWN BY THE CLOUDS AND WILL BE BELOW NORMAL. BASED ON THE HRRR AND
NAM...KEPT IN AREAS OF DRIZZLE AND A SLIGHT CHANCE OF RAIN FROM
SOUTHWEST TN ALONG THE TN RIVER INTO PORTIONS OF NORTHEAST MS EARLY
THIS MORNING.
FOR TONIGHT...DID NOT CLEAR THE SKIES QUITE AS FAST AS SOME OF THE
GUIDANCE INDICATES WITH 925 MB WINDS FROM THE NORTHEAST HELPING TO
HOLD IN THE LOW CLOUDS ESPECIALLY EAST OF THE MS RIVER.
OTHERWISE...COLD HIGH PRESSURE WILL EXTEND INTO THE MIDSOUTH FROM
THE NORTH WITH PRECIPITATION FREE CONDITIONS.
SUNSHINE WILL RETURN TO THE MIDSOUTH TUESDAY AS THE STRONG SURFACE
HIGH PRESSURE MOVES INTO THE NORTHERN PLAINS. HIGH TEMPERATURES WILL
REMAIN BELOW NORMAL TUESDAY.
FOR WEDNESDAY...A SURFACE HIGH OF 1040 MB IS FORECAST TO BE CENTERED
OVER OK AND WILL DOMINATE MIDSOUTH WEATHER. SKIES WILL BE MOSTLY
SUNNY BUT IT WILL BE COLD.
WEDNESDAY AND THURSDAY MORNINGS WILL SEE LOW TEMPERATURES DIP INTO
THE 20S AREAWIDE WITH POSSIBLY SOME UPPER TEENS ACROSS THE EXTREME
NORTHERN LOCATIONS.
NEW YEARS DAY WILL CONTINUE COLD WITH INCREASING CLOUDS FROM THE
WEST DURING THE DAY. THE BLENDED GUIDANCE INDICATES A SLIGHT CHANCE
OF RAIN SPREADING INTO PORTIONS OF EAST CENTRAL AR AND NORTH MS
BY LATE AFTERNOON AS OVERRUNNING DEVELOPS.
THE OVERRUNNING PATTERN WILL STRENGTHEN THURSDAY NIGHT WITH A WARM
FRONT ALONG THE GULF COAST. A CLOSED UPPER LEVEL LOW OVER THE
SOUTHWESTERN UNITED STATES WILL MOVE SLOWLY EASTWARD. RAIN IS
FORECAST TO SPREAD ACROSS THE MIDSOUTH. A WINTRY MIXTURE OF
PRECIPITATION CONSISTING OF SLEET...RAIN...AND POSSIBLY FREEZING
RAIN IS EXPECTED THURSDAY NIGHT INTO FRIDAY MORNING ACROSS PORTIONS
OF NORTHEAST ARKANSAS...THE MISSOURI BOOTHEEL...INTO PORTIONS OF
WEST TENNESSEE. THE AFFECTED AREA IS MAINLY ALONG AND NORTH OF A
LINE FROM HARRISBURG ARKANSAS TO COVINGTON TENNESSEE TO SAVANNAH
TENNESSEE. AT THIS TIME...ANY ACCUMULATIONS ARE EXPECTED TO BE
LIGHT. THE PRECIPITATION IS EXPECTED TO CHANGE TO ALL RAIN BY MID-
MORNING FRIDAY. BRIEF SLEET MAY OCCUR JUST TO THE SOUTH OF THIS AREA
THURSDAY NIGHT BEFORE CHANGING TO RAIN WITH TEMPERATURES ABOVE
FREEZING.
FRIDAY INTO SATURDAY LOOK VERY WET FOR THE MIDSOUTH. THE UPPER LEVEL
LOW WILL SLOWLY APPROACH FROM THE WEST WITH THE WARM FRONT TO THE
SOUTH PUSHING ONLY SLOWLY NORTHWARD. MODELS DIFFER ON THE
DEVELOPMENT OF A SURFACE LOW ALONG THE FRONT. PRECIPITABLE WATER WILL
BE ON THE INCREASE WITH VALUES REACHING GREATER THAN 1.5 INCHES
ACROSS PORTIONS OF THE REGION BY FRIDAY NIGHT / SATURDAY. ELEVATED
INSTABILITY WILL ALSO INCREASE AS THE CLOSED UPPER LOW AND SOUTHWARD
EXTENDING UPPER LEVEL TROUGH APPROACHES. SCATTERED THUNDERSTORMS CAN
BE EXPECTED BY FRIDAY NIGHT AND CONTINUING INTO SATURDAY / SATURDAY
NIGHT. RAIN MAY BE LOCALLY HEAVY...HELD OFF MENTIONING THIS THREAT
IN THE HAZARDOUS WEATHER OUTLOOK FOR NOW UNTIL CONFIDENCE INCREASES.
IT IS POSSIBLE THUNDERSTORMS TO OUR SOUTH COULD CUT US OFF FROM THE
GREATER MOISTURE AND RAINFALL. THE UPPER LEVEL TROUGH / ASSOCIATED
COLD FRONT IS FORECAST THROUGH THE REGION SATURDAY NIGHT WITH A
LINGERING CHANCE OF RAIN SUNDAY.
JCL
&&
.AVIATION...
06Z TAF CYCLE
IFR TO MVFR CIGS ARE EXPECTED OVERNIGHT WITH PATCHY FOG. MODEL
GUIDANCE HAS BEEN OVERLY AGGRESSIVE WITH CLEARING CLOUDS OUT FOR
SEVERAL RUNS NOW. WILL SIDE WITH THE MORE PESSIMISTIC GUIDANCE
AND KEEP CLOUDS AROUND FOR MOST OF THE DAY...ESPECIALLY AT TUP
WHERE CONDITIONS WILL LIKELY REMAIN MVFR AT BEST. PATCHY 3-5SM BR
IS POSSIBLE..ESPECIALLY TOWARD SUNRISE. CONFIDENCE IS HIGHEST
THAT JBR WILL SEE VFR CONDITIONS DURING THE AFTERNOON HOURS. MID
CLOUDS WILL RETURN TOMORROW NIGHT.
WINDS EAST TO NORTHEAST AROUND 5 KTS.
30
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
452 AM CST MON DEC 29 2014
.DISCUSSION...
EARLY THIS MORNING...SATELLITE SHOWED THAT LOW CLOUDS COVERED THE
MIDSOUTH. ANY CLEARING HAS STALLED AND THE LOW CLOUDS WERE EXPANDING
IN COVERAGE. TEMPERATURES WERE MOSTLY IN THE 30S EXCEPT FOR LOWER
40S ACROSS PORTIONS OF NORTHEAST MS. WINDS WERE NORTHERLY ABOUT 5 TO
10 MPH. PATCHY LIGHT RAIN LINGERED FROM PORTIONS OF SOUTHWEST TN
INTO NORTH MS.
A STRONG SURFACE HIGH PRESSURE OF ABOUT 1058 MB WILL EXTEND FROM
SOUTHWEST CANADA TO THE MIDSOUTH TODAY. LOW CLOUDS WILL SLOWLY
DECREASE FROM THE WEST ACROSS PORTIONS OF NORTHEAST AR...BUT LOW
CLOUDS WILL PERSIST EAST OF THE MS RIVER ALL DAY. IN ADDITION...HIGH
LEVEL CLOUDS WILL SPREAD IN FROM THE WEST. TEMPERATURES WILL BE HELD
DOWN BY THE CLOUDS AND WILL BE BELOW NORMAL. BASED ON THE HRRR AND
NAM...KEPT IN AREAS OF DRIZZLE AND A SLIGHT CHANCE OF RAIN FROM
SOUTHWEST TN ALONG THE TN RIVER INTO PORTIONS OF NORTHEAST MS EARLY
THIS MORNING.
FOR TONIGHT...DID NOT CLEAR THE SKIES QUITE AS FAST AS SOME OF THE
GUIDANCE INDICATES WITH 925 MB WINDS FROM THE NORTHEAST HELPING TO
HOLD IN THE LOW CLOUDS ESPECIALLY EAST OF THE MS RIVER.
OTHERWISE...COLD HIGH PRESSURE WILL EXTEND INTO THE MIDSOUTH FROM
THE NORTH WITH PRECIPITATION FREE CONDITIONS.
SUNSHINE WILL RETURN TO THE MIDSOUTH TUESDAY AS THE STRONG SURFACE
HIGH PRESSURE MOVES INTO THE NORTHERN PLAINS. HIGH TEMPERATURES WILL
REMAIN BELOW NORMAL TUESDAY.
FOR WEDNESDAY...A SURFACE HIGH OF 1040 MB IS FORECAST TO BE CENTERED
OVER OK AND WILL DOMINATE MIDSOUTH WEATHER. SKIES WILL BE MOSTLY
SUNNY BUT IT WILL BE COLD.
WEDNESDAY AND THURSDAY MORNINGS WILL SEE LOW TEMPERATURES DIP INTO
THE 20S AREAWIDE WITH POSSIBLY SOME UPPER TEENS ACROSS THE EXTREME
NORTHERN LOCATIONS.
NEW YEARS DAY WILL CONTINUE COLD WITH INCREASING CLOUDS FROM THE
WEST DURING THE DAY. THE BLENDED GUIDANCE INDICATES A SLIGHT CHANCE
OF RAIN SPREADING INTO PORTIONS OF EAST CENTRAL AR AND NORTH MS
BY LATE AFTERNOON AS OVERRUNNING DEVELOPS.
THE OVERRUNNING PATTERN WILL STRENGTHEN THURSDAY NIGHT WITH A WARM
FRONT ALONG THE GULF COAST. A CLOSED UPPER LEVEL LOW OVER THE
SOUTHWESTERN UNITED STATES WILL MOVE SLOWLY EASTWARD. RAIN IS
FORECAST TO SPREAD ACROSS THE MIDSOUTH. A WINTRY MIXTURE OF
PRECIPITATION CONSISTING OF SLEET...RAIN...AND POSSIBLY FREEZING
RAIN IS EXPECTED THURSDAY NIGHT INTO FRIDAY MORNING ACROSS PORTIONS
OF NORTHEAST ARKANSAS...THE MISSOURI BOOTHEEL...INTO PORTIONS OF
WEST TENNESSEE. THE AFFECTED AREA IS MAINLY ALONG AND NORTH OF A
LINE FROM HARRISBURG ARKANSAS TO COVINGTON TENNESSEE TO SAVANNAH
TENNESSEE. AT THIS TIME...ANY ACCUMULATIONS ARE EXPECTED TO BE
LIGHT. THE PRECIPITATION IS EXPECTED TO CHANGE TO ALL RAIN BY MID-
MORNING FRIDAY. BRIEF SLEET MAY OCCUR JUST TO THE SOUTH OF THIS AREA
THURSDAY NIGHT BEFORE CHANGING TO RAIN WITH TEMPERATURES ABOVE
FREEZING.
FRIDAY INTO SATURDAY LOOK VERY WET FOR THE MIDSOUTH. THE UPPER LEVEL
LOW WILL SLOWLY APPROACH FROM THE WEST WITH THE WARM FRONT TO THE
SOUTH PUSHING ONLY SLOWLY NORTHWARD. MODELS DIFFER ON THE
DEVELOPMENT OF A SURFACE LOW ALONG THE FRONT. PRECIPITABLE WATER WILL
BE ON THE INCREASE WITH VALUES REACHING GREATER THAN 1.5 INCHES
ACROSS PORTIONS OF THE REGION BY FRIDAY NIGHT / SATURDAY. ELEVATED
INSTABILITY WILL ALSO INCREASE AS THE CLOSED UPPER LOW AND SOUTHWARD
EXTENDING UPPER LEVEL TROUGH APPROACHES. SCATTERED THUNDERSTORMS CAN
BE EXPECTED BY FRIDAY NIGHT AND CONTINUING INTO SATURDAY / SATURDAY
NIGHT. RAIN MAY BE LOCALLY HEAVY...HELD OFF MENTIONING THIS THREAT
IN THE HAZARDOUS WEATHER OUTLOOK FOR NOW UNTIL CONFIDENCE INCREASES.
IT IS POSSIBLE THUNDERSTORMS TO OUR SOUTH COULD CUT US OFF FROM THE
GREATER MOISTURE AND RAINFALL. THE UPPER LEVEL TROUGH / ASSOCIATED
COLD FRONT IS FORECAST THROUGH THE REGION SATURDAY NIGHT WITH A
LINGERING CHANCE OF RAIN SUNDAY.
JCL
&&
.AVIATION...
06Z TAF CYCLE
IFR TO MVFR CIGS ARE EXPECTED OVERNIGHT WITH PATCHY FOG. MODEL
GUIDANCE HAS BEEN OVERLY AGGRESSIVE WITH CLEARING CLOUDS OUT FOR
SEVERAL RUNS NOW. WILL SIDE WITH THE MORE PESSIMISTIC GUIDANCE
AND KEEP CLOUDS AROUND FOR MOST OF THE DAY...ESPECIALLY AT TUP
WHERE CONDITIONS WILL LIKELY REMAIN MVFR AT BEST. PATCHY 3-5SM BR
IS POSSIBLE..ESPECIALLY TOWARD SUNRISE. CONFIDENCE IS HIGHEST
THAT JBR WILL SEE VFR CONDITIONS DURING THE AFTERNOON HOURS. MID
CLOUDS WILL RETURN TOMORROW NIGHT.
WINDS EAST TO NORTHEAST AROUND 5 KTS.
30
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
857 AM CST MON DEC 29 2014
.UPDATE...
QUICK MORNING UPDATE TO EXTEND DENSE FOG ADVISORY FARTHER WEST
BASED ON LATEST OBSERVATIONAL TRENDS. HRRR AND RUC VISIBILITY
PROGS SHOW THIS FOG HANGING ON THROUGH LATE MORNING.
ADDITIONALLY...HAVE SEEN SOME REPORTS ON SOCIAL MEDIA OF LIGHT
ICING ON BRIDGES IN BRAZOS COUNTY /AROUND THE BRYAN AREA/ AND
LOCALIZED FREEZING FOG WILL ALSO BE POSSIBLE IN THIS AREA FOR A
BRIEF PERIOD THIS MORNING BEFORE TEMPERATURES WARM ABOVE FREEZING.
HUFFMAN
&&
.PREV DISCUSSION... /ISSUED 408 AM CST MON DEC 29 2014/
DISCUSSION...
LOW CLOUDS, DRIZZLE & FOG ACROSS EASTERN 2/3 OF THE CWA SHOULD
BEGIN TO ERODE LATE THIS MORNING. MIGHT TAKE A BIT LONGER ACROSS
NE PARTS...WHICH LIKE SUNDAY...COULD PLAY HAVOC WITH HIGH TEMPS
DEPENDING ON TIMING & BREAKS OF SUN.
LEADING EDGE OR ARCTIC AIRMASS NOW SPILLING INTO NCNTL PARTS OF
THE COUNTRY WILL BEGIN FILTERING INTO SE TX ON TUE. IT`LL BE A
GRADUAL PROCESS WITH CAA CONTINUING WED/THU. ONE THING FUTURE
SHIFTS WILL NEED TO KEEP A CLOSE AN EYE ON IS PRECIP CHANCES NEW
YEARS EVE. BOTH THE 00Z & 06Z RUNS OF THE NAM12 SHOW FAIRLY ROBUST
MOISTURE ASCENT OVER COOLER SFC AIRMASS WITH INCREASING -RA
COVERAGE THRU THE EVNG AND OVERNIGHT HOURS WED. THIS IS 12-18 HOURS
EARLIER THAN WHAT GLOBAL MODELS/GUIDANCE HAVE BEEN AND ARE STILL
INDICATING. TYPICALLY GIVE MORE FCST WEIGHT TO NAM12 IN THESE AIRMASSES
AND WENT AHEAD AND BUMPED POPS UP WED NIGHT...BUT THEY MAY STILL
BE SIGNIFICANTLY UNDERDONE.
COLDEST DAY OF THE WEEK SHOULD BE NEW YEARS DAY (THURS) WITH EXPECTED
CLOUDS/PRECIP LIMITING ANY WARM-UP.
COASTAL TROF TAKES SHAPE LATE THURS AND FRI AS SFC HIGH PRES MOVES
OFF TO THE EAST AND UPPER TROF SLOWLY APPROACHES FROM THE WEST.
COMBINATION OF UPGLIDE, MESSY SW FLOW ALOFT & COASTAL TROF WILL
PROVIDE CONTINUED GOOD CHANCES OF PRECIP THRU SAT AFTN. FWIW THIS
FAR OUT - THE 00Z GUIDANCE DOESN`T BRING THE WARM SECTOR NEARLY
AS FAR INLAND AS PAST RUNS. PACIFIC FRONT CLEARS THE PRECIP OUT
LATE SAT AS UPPER TROF DEPARTS. 47
MARINE...
GENERALLY LIGHT N/NELY WINDS TO PREVAIL THE NEXT DAY (OR SO) BEFORE
STRENGTHENING TUES IN RESPONSE TO THE UPPER LEVEL STORM SYSTEM DEEP-
ENING OUT TO THE WEST. WE COULD SEE SCEC/SCA FLAGS FOR THE UPPER TX
COASTAL WATERS BY TUES NIGHT...LINGERING ON INTO LATE THURS. S/SELY
WINDS PROGGED TO RETURN FRI AS A WARM FRONT MOVES ASHORE.
AVIATION...
FOGGY START TO THE DAY WITH LIFR VIS/CIGS PREVAILING ACROSS THE SRN
TWO THIRDS OF THE FA. THESE CONDITIONS COULD BE SLOW TO CLEAR GIVEN
THE VERY LIGHT WINDS JUST ABOVE THE SFC...BUT WE SHOULD SEE VFR CIG
BY THE AFTN. 41
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 55 39 51 34 42 / 0 0 0 10 20
HOUSTON (IAH) 57 42 56 37 48 / 0 0 0 0 20
GALVESTON (GLS) 54 49 56 43 51 / 0 0 0 10 20
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...DENSE FOG ADVISORY UNTIL 11 AM CST THIS MORNING FOR THE
FOLLOWING ZONES: BRAZORIA...BRAZOS...FORT BEND...
GALVESTON...GRIMES...HARRIS...HOUSTON...LIBERTY...MADISON...
MATAGORDA...MONTGOMERY...POLK...SAN JACINTO...TRINITY...
WALKER...WALLER.
GM...NONE.
&&
$$
DISCUSSION...99
AREA FORECAST DISCUSSION...UPDATED
NWS AUSTIN/SAN ANTONIO TX
1148 PM CST SUN DEC 28 2014
.AVIATION.../06Z TAF CYCLE/
ALL SITES ARE VFR SKC AS OF 29/06Z WITH LIGHT TO CALM WINDS. NWP
OUTPUT CONTINUES TO SUGGEST FOG DEVELOPMENT ALONG THE RIO GRANDE
VALLEY AND SPREADING EASTWARD TOWARDS KSAT 10-16Z TIME FRAME.
TRENDS HAVE BACKED AWAY FROM EASTWARD EXPANSION BUT FEEL KSSF HAS
SLIGHTLY GREATER CHANCE THEN KSAT. HAVE KEPT KAUS/KSAT VFR
THROUGH MORNING HOURS BUT HAVE PLACED HIGH END MVFR FOR KSSF FROM
10-15Z. HRRR OUTPUT AND RAP/NAM BUFR SOUNDINGS CONTINUE TO
INDICATE FOG DEVELOPMENT AT KDRT AND FORECAST FOLLOWS SUITE WITH
3SM VIS RESTRICTIONS 10-16Z DESPITE GFSLAMP GUIDANCE NOT
SUGGESTING FOG. EXPECT VFR CONDITIONS MONDAY AFTER FOG DISSIPATES
THROUGH MUCH OF THE OVERNIGHT INTO EARLY TUESDAY MORNING BEFORE
LOWER CLOUDS RETURN LATE MORNING TUESDAY. /ALLEN/
&&
.PREV DISCUSSION... /ISSUED 922 PM CST SUN DEC 28 2014/
UPDATE...
THE FORECAST HAS BEEN UPDATED FOR THE REMAINDER OF TONIGHT INTO
EARLY MONDAY MORNING. THE MAIN UPDATE WAS TO ADD A MENTION OF
PATCHY FOG ACROSS THE RIO GRANDE PLAINS AND SOUTHERN EDWARDS
PLATEAU. MINOR UPDATES HAVE ALSO BEEN MADE TO THE LATEST
TEMPERATURES...DEW POINTS AND WINDS TO ACCOUNT FOR RECENT
OBSERVATIONS. FINALLY...WE DID DECREASE OVERNIGHT LOW TEMPERATURES
SLIGHTLY ACROSS THE NORTHWESTERN HILL COUNTRY.
PREV DISCUSSION... /ISSUED 335 PM CST SUN DEC 28 2014/
SHORT TERM (TONIGHT THROUGH MONDAY NIGHT)...
AN UPPER LEVEL TROUGH IS EXITING TO THE EAST OF SOUTH CENTRAL
TEXAS THIS AFTERNOON. SKIES HAVE CLEARED TO NEAR I-35. SKIES WILL
CLEAR ACROSS THE REMAINDER OF OUR AREA BY SUNSET. THIS SETS THE
STAGE FOR WIDESPREAD FREEZING TEMPERATURES BY MONDAY MORNING. WE
HAVE ISSUED A FREEZE WARNING FOR LATE TONIGHT INTO MONDAY MORNING
FOR OUR SOUTHERN TWO TIERS OF COUNTIES...EXCEPT FOR THE SOUTHWEST.
THESE AREAS HAVE NOT YET REACHED FREEZING THIS FALL/WINTER.
MEANWHILE...THE HILL COUNTRY AND ALONG THE ESCARPMENT ALREADY HAVE
SEEN FREEZING TEMPERATURES THIS WINTER SEASON WHILE THE RIO GRANDE
PLAINS WILL FALL TO JUST ABOVE FREEZING. SEE OUR SPECIAL WEATHER
STATEMENT FOR DETAILS FOR THOSE AREAS. A BRIEF WARM UP IS EXPECTED
ON MONDAY ON SOUTH TO SOUTHWEST WINDS. LATE MONDAY NIGHT ANOTHER
COLD FRONT IS EXPECTED TO ENTER THE FAR NORTHERN HILL COUNTRY.
TEMPERATURES SHOULD STAY ABOVE FREEZING MONDAY NIGHT ON MIXING
ALONG AND AHEAD OF FRONT.
LONG TERM (TUESDAY THROUGH SUNDAY)...
THE COLD FRONT WILL SURGE ACROSS THE REMAINDER OF SOUTH CENTRAL
TEXAS TUESDAY MORNING. HIGH TEMPERATURES WILL BE REACHED LATE
MORNING TO MIDDAY AS CLOUDS INCREASE DUE TO MOIST SOUTHERLY FLOW
RIDING OVER COLD ADVECTION IN THE LOWER LEVELS. MODELS ARE IN
BETTER AGREEMENT ON THE PATTERN EVOLUTION IN THE LONG TERM.
ALTHOUGH...SOME DISAGREEMENT REMAINS AND THE FORECAST MAY CHANGE
OVER THE NEXT FEW DAYS. AN UPPER UPPER LEVEL TROUGH DROPPING DOWN
THE WEST COAST ON TUESDAY CLOSES OFF OVER SOUTHERN CALIFORNIA ON
WEDNESDAY INTO THURSDAY AND THEN OPENS UP AND MOVE ACROSS TEXAS
FRIDAY INTO EARLY SATURDAY. ISENTROPIC LIFT DEVELOPS TUESDAY NIGHT
INTO WEDNESDAY LEADING TO AREAS OF LIGHT RAIN INITIALLY ALONG THE
RIO GRANDE...THEN SPREADING ACROSS THE REMAINDER OF THE AREA.
PERIODS OF LIGHT TO OCCASIONALLY MODERATE RAIN OR SHOWERS WILL
CONTINUE THROUGH FRIDAY NIGHT. THERE IS A THREAT FOR WINTER TYPE
PRECIPITATION DURING THE LATE NIGHT INTO MORNING HOURS MAINLY FOR
PARTS OF THE HILL COUNTRY TUESDAY NIGHT THROUGH THURSDAY (NEW
YEARS DAY) MORNING. FORECAST SOUNDINGS SHOW A THICK LAYER ABOVE
FREEZING DEVELOPING ON TOP OF A SHALLOW SUBFREEZING BOUNDARY
LAYER. FREEZING RAIN IS THE LIKELY WINTER TYPE PRECIPITATION THAT
IS EXPECTED WHERE TEMPERATURES DROP BELOW FREEZING. HOWEVER...NO
SIGNIFICANT ICE ACCUMULATIONS ARE EXPECTED. SHOULD THE RAIN BECOME
MORE CONVECTIVE...THEN SOME SLEET MAY BE POSSIBLE OVER A GREATER
AREA. FINALLY...THERE MAY BE A THREAT OF LIGHT SNOW ACROSS WESTERN
EDWARDS PLATEAU PRIOR TO THE DEVELOPMENT OF THE WARM LAYER ALOFT.
BY THURSDAY AFTERNOON...THE LOWER LEVELS WARM ABOVE FREEZING WITH
ONLY A COLD RAIN EXPECTED. AS THE UPPER LOW APPROACHES AND MOVES
ACROSS...SOME THUNDERSTORMS ARE POSSIBLE DUE TO ELEVATED
INSTABILITY THURSDAY NIGHT THROUGH FRIDAY NIGHT. THE RAINS END FROM
WEST TO EAST BY SATURDAY MORNING. FAIR SKIES AND MUCH WARMER
DAYTIME TEMPERATURES ARE EXPECTED NEXT WEEKEND.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 32 61 39 46 36 / 0 0 - 10 10
AUSTIN BERGSTROM INTL AIRPORT 25 60 35 46 36 / 0 0 - 10 10
NEW BRAUNFELS MUNI AIRPORT 29 61 36 48 38 / 0 0 - 10 10
BURNET MUNI AIRPORT 29 61 36 43 32 / 0 0 - 10 20
DEL RIO INTL AIRPORT 34 62 40 56 37 / 0 0 - 10 30
GEORGETOWN MUNI AIRPORT 28 60 35 44 34 / 0 0 - 10 10
HONDO MUNI AIRPORT 28 62 35 51 38 / 0 0 - 10 20
SAN MARCOS MUNI AIRPORT 29 61 36 47 37 / 0 0 - 10 10
LA GRANGE - FAYETTE REGIONAL 31 59 40 50 39 / 0 0 - 10 10
SAN ANTONIO INTL AIRPORT 32 62 39 49 38 / 0 0 - 10 20
STINSON MUNI AIRPORT 32 61 39 51 39 / 0 0 - 10 20
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
FREEZE WARNING UNTIL 9 AM CST MONDAY FOR THE FOLLOWING COUNTIES:
ATASCOSA...DE WITT...FAYETTE...FRIO...GONZALES...KARNES...LAVACA...
UVALDE...WILSON...ZAVALA.
&&
$$
MESOSCALE/AVIATION...15
SYNOPTIC/GRIDS...24
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1138 PM CST SUN DEC 28 2014
.DISCUSSION...
06Z TAF DISCUSSION IN AVIATION SECTION...
&&
.AVIATION...
SATELLITE IMAGERY SHOWS THAT CLEARING LINE HAS STOPPED ITS
EASTWARD PROGRESS JUST WEST OF KSGR/KCXO/KUTS. SO WILL KEEP CIGS
VFR FOR KCLL BUT MAINLY IFR FOR ALL OTHER TERMINALS. STILL
ANTICIPATE SOME LIFR CIGS TO DEVELOP WITH CLOSE T/TD SPREADS.
LATEST TRENDS IN HRRR HOLD ONTO IFR CIGS AND EVEN SPOTTY LIFR.
LOOK FOR CIGS TO IMPROVE LATE MORNING INTO THE AFTERNOON TOMORROW.
MAY GET VFR AREA WIDE IN THE EVENING INTO TOMORROW NIGHT. HIGH
PRESSURE OVER THE AREA WILL KEEP WINDS LIGHT AND VARIABLE.
39
&&
.PREV DISCUSSION... /ISSUED 857 PM CST SUN DEC 28 2014/
DISCUSSION...
HIGH PRESSURE WILL BUILD OVERHEAD AS THE SHORTWAVE TROUGH MOVES
EASTWARD OF THE FORECAST AREA. EXPECT CLEARING CONDITIONS AND
COLDER TEMPERATURES OVERNIGHT TONIGHT. FORECAST SOUNDINGS AND
GUIDANCE ALSO IS FORECASTING PATCHY FOG. BECAUSE OF THE CLEARING
SKIES AND THE ABUNDANCE OF SURFACE MOISTURE DUE TO THE RAINFALL...
PATCHY FOG DOES LOOK MORE LIKELY.
UPDATE TO TAKE OUT RAINFALL CHANCES AND TO ADD PATCHY FOG
OVERNIGHT TONIGHT AND ENDING MID MORNING MONDAY.
40
PREV DISCUSSION... /ISSUED 553 PM CST SUN DEC 28 2014/
DISCUSSION...
00Z TAF DISCUSSION IN AVIATION SECTION.
AVIATION...
LATEST RADAR TRENDS HAS RAIN ASSOCIATED WITH SHORT WAVE TROUGH
MOVING OUT OF THE AREA. THIS SHOULD ALLOW FOR VSBY/CIGS TO IMPROVE
THE NEXT SEVERAL HRS BUT STILL QUITE A BIT OF MOISTURE TRAPPED IN
COLD AIRMASS. SATELLITE IMAGERY SHOWS CLEARING LINE APPROACHING
KCLL FROM THE WEST. THIS MAY PUSH FAR ENOUGH EAST TO ALLOW FOR
IMPROVING CIGS BUT NOT SURE HOW FAR WEST IT WILL MOVE.
KCLL...THINK THERE SHOULD BE CLEARING FOR MOST OF THE NIGHT BUT
NOT SEEING MODELS INDICATE IF CIGS/VSBY FILL BACK IN THROUGH THE
MORNING WITH RADIATIONAL COOLING. WILL KEEP TAF VFR.
KUTS/KCXO/KIAH/KHOU/KSGR...WITH RAIN MOVING OUT EXPECT VSBY/CIGS
TO IMPROVE SOME. MAY BREAK OUT OF OVC IFR CONDITIONS TO BKN BUT
STILL POSSIBLE FOR IFR TO HOLD ON THROUGH MORNING. CONCERNED
CLEARING COULD OCCUR AS DRIER AIR TRIES TO MIX INTO THE AREA SO
WILL NEED TO WATCH FOR THAT AND MAY GET CIGS TO GO SCT FROM 03Z-
09Z. HRRR 19-21Z RUNS SHOW THIS TREND IN CIGS SCATTERING OUT BUT
THEN GET LOW IFR TO BUILD BACK IN FROM 09Z TO 15Z. TAFS WILL BE
GEARED TOWARDS THESE LOWER CIGS IN THE MORNING AND THEN SLOWLY
GOING IFR/MVFR WITH VFR BY LATE AFTERNOON TOMORROW. WITH HIGH
PRESSURE BUILDING IN...LIGHT WINDS EXPECTED.
KLBX/KGLS...MORE LIKELY THAT CLEARING WILL NOT OCCUR FROM THE WEST
FOR THESE TERMINALS SO HAVE MORE CONFIDENCE IN IFR CIGS HOLDING
THROUGH THE NIGHT. ALSO POSSIBLE FOR CIGS TO DROP IN THE MORNING
TO LOW IFR AS THERE WILL NOT BE ANY DRIER AIR TO MIX AS COMPARED
TO MORE INLAND SIGHTS. OTHERWISE TRENDS SHOULD BE SIMILAR TO
INLAND TERMINALS WITH IFR UNTIL LATE MORNING AND THE MVFR IN THE
AFTERNOON.
39
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 33 58 38 51 35 / 10 0 0 10 10
HOUSTON (IAH) 36 59 42 57 38 / 10 0 0 10 10
GALVESTON (GLS) 43 57 48 56 44 / 10 0 0 10 10
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...40
AVIATION/MARINE...39
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
351 PM EST MON DEC 29 2014
.SYNOPSIS...
COLD SURFACE HIGH PRESSURE WILL CONTINUE TO WEDGE DOWN FROM THE
NORTH ALONG THE APPALACHIANS TONIGHT WHILE A WEAK UPPER LEVEL
DISTURBANCE IS EXPECTED TO PASS FROM WEST TO EAST ACROSS THE AREA
TONIGHT THROUGH EARLY TUESDAY. VERY LIGHT PRECIPITATION ASSOCIATED
WITH THIS FEATURE IS EXPECTED TO CHANGE OVER TO SNOW ACROSS THE
NORTHERN PORTION OF THE REGION...WITH ACCUMULATIONS OF AN INCH OR
LESS...MAINLY ALONG AND NORTH OF U.S. 460. DRY BUT CONTINUED COLD
HIGH PRESSURE WILL BEGIN TO PUSH IN FROM THE WEST LATER TUESDAY
AND LAST UNTIL LATE IN THE WEEK.
&&
.NEAR TERM /THROUGH TUESDAY/...
AS OF 350 PM EST MONDAY...
TRICKY FCST OVERNIGHT IN REGARDS TO THE AMOUNTS AND LOCATIONS OF
VERY LIGHT PRECIP AS A WEAK UPPER WAVE PASSES OVER THE DEEPENING
COLD AIR DAMMING WEDGE AS COLD SFC HIGH PRESSURE SPILLS DOWN FROM
THE NORTH. MODEL GUIDANCE ALL QUITE DIFFERENT WITH MAIN
OPERATIONAL NCEP MODELS TRENDING UPWARD SOMEWHAT WITH AS MUCH AS A
QUARTER TO TWO THIRDS OF AN INCH LIQUID EQUIV...MAINLY OVER
THE WESTERN PORTIONS. EVEN ORIGINALLY DRIER GFS NOW AS MUCH AS
FOUR TENTHS OF AN INCH OVER THE ALLEGHANY HIGHLANDS. MEANWHILE
CONVECTIVE-ALLOWING MODELS GENERALLY LESS THAN TWO TENTHS OF AN
INCH. AM LEANING ON THE LIGHT SIDE OF THE QPF OPTIONS...MORE IN
LINE WITH IDEA OF MOST OF THE HRRR RUNS...AND POSSIBILITY THAT
MORE OF THE PRECIP ACTUALLY ENDS UP BACK ACROSS THE FOOTHILLS AND
PIEDMONT AGAIN. AM LEAVING SOME VERY LOW LIKELY POPS FOR TONIGHT
ACROSS PARTS OF THE MOUNTAINS...WITH HIGHER CHANCE POPS NOW ACROSS
THE FOOTHILLS. THE ISSUE OF MOISTURE DEPTH IS STILL CONCERN AS
WELL...AND WHILE I DID NOT INCLUDE ANY DRIZZLE IN THE
GRIDS...THERE COULD VERY WELL BE PERIODS OF TIME AND PORTIONS OF
THE AREA WHERE WE SEE MORE DRIZZLE DUE TO LACK OF ICE CRYSTAL
GROWTH ALOFT. THIS WOULD CUT DOWN ON ANY OF THE ALREADY LIGHT
SNOW ACCUMS IF AND WHERE THIS HAPPENS. WARM NOSE DOES NOT SEEM TO
BE PRESENT IN ANY MODEL SOUNDINGS...SO GOING WITH EITHER RAIN OR
SNOW...AND SO SFC TEMPS WILL BE THE KEY TO THAT CHANGEOVER. AS FAR
AS THE TEMPS GO...ALREADY GETTING COLDER THIS AFTERNOON THAN WE
EARLIER ANTICIPATED...AND SOME HIGHER ELEVATIONS HAVE REPORTS
SOME VERY LIGHT SNOW. THUS LOWERED TEMPS THROUGH EVENING AND
OVERNIGHT A FEW DEGREES FROM PREVIOUS FORECAST WHERE WEDGE IS
EXPECTED TO BE THE STRONGEST...AND THIS RESULTS IN A SLIGHTLY
EARLIER CHANGEOVER FROM LIGHT RAIN TO LIGHT SNOW...BUT EXCEPT FOR
HIGHER ELEVATIONS...THIS WILL STILL BE AFTER MIDNIGHT.
BOTTOM LINE IS ONLY VERY LIGHT AMOUNTS OF SNOW ACCUM
EXPECTED LATE TONIGHT AND IN THE EARLY MORNING HOURS TUESDAY...AND
IT WILL LIKELY HAVE TROUBLE STICKING AS WELL EXCEPT FOR HIGHEST
ELEVATIONS. HAVE DUSTING TO LESS THAN AN INCH GENERALLY NORTH OF
U.S. 460...AND DOWN THE BLUE RIDGE TO NEAR MEADOWS OF DAN. MAYBE
AN INCH TO ALMOST TWO ALONG HIGHEST RIDGES OF ALLEGHANY HIGHLANDS
AND ALONG BLUE RIDGE PARKWAY NORTH OF PEAKS OF OTTER. MOST ROADS
NOT EXPECTED TO SEE ANY ACCUMULATION.
ANY LINGERING PRECIP EVAPORATES QUICKLY BY MIDDAY TUESDAY AS
SHORT WAVE PASSES BY AND DRIER AIR FROM NORTH CONTINUES TO FILTER
IN. WESTERLY FLOW AT RIDGE TOP LEVEL DEVELOPS BUT VERY WEAK FLOW
AND LITTLE MOISTURE TO WORK WITH SO NO ISSUES WITH ANY UPSLOPE
SNOW SHOWERS IN FAR WEST IT APPEARS. MAX TEMPS MAY BE TRICKY WITH
SOME SUNSHINE LATE IN THE DAY...BUT THIS COULD BE TOO LATE FOR LOW
SUN ANGLE TO HAVE MUCH IMPACT...SO FOR NOW GOING ON COLD SIDE OF
GUIDANCE WITH ONLY ABOUT A 5-7 DEGREE RISE FROM OVERNIGHT LOWS.
ABOVE FREEZING BY LATE MORNING SO ANY MINOR AMOUNTS OF SNOW THAT
DOES FALL WILL BE GONE BY NOON MOST LIKELY.
FINALLY...COLD WEDGE WILL KEEP SOME AREAS OF FOG AND LOW CEILINGS
AROUND...MOST ESPECIALLY NEAR THE BLUE RIDGE...BUT ALSO SOME OF
THE MTN VALLEYS AS WELL...SO BLANKED THE FOOTHILLS AND WESTWARD
WITH PATCHY FOG THROUGH TOMORROW MORNING IN THE FORECAST GRIDS BUT THIS
MAY LINGER THROUGH MUCH OF THE DAY IN SPOTS UNTIL THE WEAK WESTERLY
FLOW CAN PUSH EAST.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
AS OF 200 PM EST MONDAY...
A LARGE AREA OF HIGH PRESSURE WILL BUILD SOUTH FROM THE ROCKIES LATE
TUESDAY...THEN INTO THE SOUTHEAST U.S. BY THURSDAY EVENING KEEPING
DRY WEATHER FOR OUR AREA DURING THIS PORTION OF THE FORECAST.
ADJUSTED TEMPS DOWN A FEW DEGREES WEDNESDAY MORNING AND WEDNESDAY
AFTERNOON UNDER GOOD COLD AIR ADVECTION. BY THURSDAY MORNING
MODELS ARE IN GOOD AGREEMENT THAT SFC HIGH NOSES INTO OUR
AREA ALLOWING VALLEY WINDS TO DIMINISH. THIS COMBINED WITH THE
DRY AIR MASS IN PLACE SHOULD ALLOW TEMPS TO DROP BELOW GUIDANCE
VALUES. THE EXCEPTION WILL BE ON THE RIDGETOPS WHERE 850MB WINDS
WILL KEEP TEMPS WARMER.
HEIGHTS RISE ON THURSDAY AS AN UPPER RIDGE BEGINS TO BUILD IN THE
CENTRAL U.S. IN ADVANCE OF A SOUTHWEST U.S. UPPER LOW.
THIS...COMBINED WITH DOWNSLOPING WINDS...SHOULD ALLOW FOR A NICE
RECOVERY IN TEMPS THURSDAY. WENT A DEGREE OR TWO ABOVE GUIDANCE FOR
HIGHS.
ONLY OTHER CHANGE TO THE FORECAST WAS TO INCREASE THE WINDS ABOVE
3500 FEET WEDNESDAY AND THURSDAY AS A SWIFT MOVING NORTHERN STREAM
SHORTWAVE PASSES THROUGH THE EASTERN GREAT LAKES THROUGH NEW ENGLAND
DURING THIS TIME.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 235 PM EST MONDAY...
DRY AND SEASONABLY COOL WEATHER IS EXPECTED OVER THE BLACKSBURG
FORECAST AREA FRIDAY MORNING AS A WEAK SHORT WAVE IN NORTHERN STREAM
SCOOTS EAST THROUGH NEW ENGLAND...WITH COOL HIGH PRESSURE BUILDING
SOUTHWESTWARD IN ITS WAKE.
HOWEVER...MUCH OF THE REST OF THE LONG TERM FORECAST FROM FRIDAY
AFTERNOON INTO MONDAY APPEARS TO BE MUCH MORE UNCERTAIN...WITH
SIGNIFICANT AND PERSISTENT DISPARITY EXISTING BETWEEN THE LONGER-
TERM MODELS IN REFLECTING STRENGTH AND PLACEMENT OF NORTHERN
STREAM...AND ITS INFLUENCE ON SOUTHERN STREAM CLOSED LOW SOUTH OF
THE FOUR CORNERS AREA ON FRIDAY AFTERNOON THAT IS FORECAST TO
GRADUALLY LIFT NORTHEAST AND FILL AS IT PROGRESSES FROM THE SOUTHERN
PLAINS UP THROUGH THE OHIO VALLEY OVER THE WEEKEND.
ECMWF MAINTAINS A MORE PERSISTENT CLOSED UPPER LOW THAT IS MUCH LESS
AMPLIFIED...YET LESS PROGRESSIVE AND FURTHER SOUTH...RESULTING IN
INCREASING ISENTROPIC LIFT AND RAIN MOVING INTO AT LEAST THE
SOUTHWESTERN HALF OF THE BLACKSBURG FORECAST AREA BY/DURING FRIDAY
AFTERNOON...BUT NOT ENDING UNTIL PASSAGE OF OPENING/WEAKENING UPPER
TROF ON SUNDAY NIGHT.
GFS...WHICH REFLECTS A MORE AMPLIFIED...YET EVENTUALLY MORE
PROGRESSIVE AND NORTHERN SYSTEM PLACEMENT...HOLDS BACK RAIN SHIELD
UNTIL SATURDAY DUE TO INFLUENCE OF LARGER AND STRONGER DRY SURFACE
HIGH PRESSURE SYSTEM OVER NEW ENGLAND. GFS ALSO THE COLDER OF THE
LONGER RANGE SOLUTIONS...SINCE STRONGER SURFACE RIDGE TO NORTHEAST
WOULD LOCK COOL-WEDGE IN PLACE OVER THE BLACKSBURG FORECAST AREA.
HOWEVER...BEING MORE PROGRESSIVE...RAIN EVENT ENDS A BIT EARLIER
THAN ECMWF SOLUTION...ON SUNDAY AFTERNOON WITH PASSAGE OF UPPER
TROF...BUT WITH PERHAPS SOME COLD ADVECTION UPSLOPE PRECIPITATION
CONTINUING ACROSS THE WESTERN FLANKS OF THE APPALACHIANS UNTIL
AROUND DAYBREAK MONDAY.
BOTH MODELS HAVE BEEN INCONSISTENT IN TIMING AND PLACEMENT OF SYSTEM
THOUGH THIS TIMEFRAME FOR AT LEAST THE PAST SEVERAL RUNS...WHICH IS
NOT ALL THAT SURPRISING CONSIDERING ACTIVE NORTHERN STREAM CLASHING
WITH INITIALLY CLOSED AND STAGNANT SOUTHERN STREAM SYSTEM...SO MODEL
BLEND/ENSEMBLE APPROACH BEST TO APPLY FOR LONG TERM FORECAST UNTIL
CONFIDENCE INCREASES IN MOVING TOWARD ANY PARTICULAR SOLUTION.
NEITHER MODEL INDICATING THAT THICKNESSES WILL BE ESPECIALLY
CRITICAL FOR P-TYPE ISSUES...MEANING A MAINLY WET RATHER THAN WHITE
FORECAST OVER THE WEEKEND. HOWEVER...IF COLDER GFS SOLUTION
VERIFIES...THICKNESSES MAY BE CLOSE ENOUGH TO CRITICAL VALUES NORTH
OF HIGHWAY 64 TO WARRANT AT LEAST A NOMINAL INSERTION OF A P-TYPE
MIX DURING TIME OF PRECIPITATION ONSET...AND PERHAPS FOLLOWING
PASSAGE OF MAIN SYSTEM IN THE NORTHWESTERN MOUNTAINS ON SUNDAY NIGHT
PROVIDED THAT POST FRONTAL COLD ADVECTION IS SUFFICIENTLY STRONG.
REGARDLESS OF TIMING AND PLACEMENT DIFFERENCES...ALL LONGER RANGE
MODELS INDICATE THAT MONDAY WILL BE DRY FOLLOWING PASSAGE OF THE
MAIN UPPER SYSTEM...WITH ANY ADDITION SOUTHERN STREAM ENERGY LIKELY
TO BE DEFLECTED TO OUR SOUTH AS NORTHERN STREAM TROFING GRADUALLY
STRENGTHENS AND AMPLIFIES FROM THE UPPER GREAT LAKES EAST INTO THE
NORTHEASTERN PORTION OF THE NATION FROM MONDAY INTO THE MID WEEK
PERIOD.
&&
.AVIATION /20Z MONDAY THROUGH SATURDAY/...
AS OF 100 PM EST MONDAY...
IFR TO LIFR CONDITIONS EXPECTED TO CONTINUE AT ALL AIRPORTS
THROUGH AT LEAST TONIGHT...AND FOR WESTERN AIRPORTS EVEN INTO
EARLY PART OF TUESDAY...UNDER THE INFLUENCE OF COLD AIR DAMMING
WHICH IS ONLY STRENGTHENING WITH TIME. KLYH CURRENTLY MVFR BUT
EXPECTED TO DROP TO IFR BY EARLY EVENING IF NOT SOONER. LOW
CONFIDENCE IN WHEN CONDITIONS MAY BEGIN TO BREAK OUT AND LIFT
EARLY TUESDAY...AND MAY HAPPEN AT KBLF SOONER THAN TAF CURRENTLY
INDICATES. MORE CONFIDENT THAT KROA AND KLYH WILL IMPROVE TO AT
LEAST MVFR DURING TUESDAY MORNING AS DRIER AIR CONTINUES TO FILTER
DOWN FROM NORTH...AND EVENTUALLY KDAN AS WELL BEFORE 18Z.
IN ADDITION...ALL AIRPORTS EXCEPT FOR KDAN SHOULD SEE SOME VERY
LIGHT RAIN CHANGE TO LIGHT SNOW AFTER MIDNIGHT...BUT NOT EXPECTED
TO STICK MUCH AT ALL EXCEPT FOR THE HIGHER ELEVATION AIRPORTS SUCH
AS KLWB...AND KBCB. NOT SURE IT WILL BE COLD ENOUGH TO REALLY
STICK AT KBLF AND KROA OR KLYH. KDAN LIKELY WILL NOT EVEN SEE
CHANGEOVER. IN ANY CASE...SNOW AMOUNTS WOULD ONLY APPROACH AN INCH
IN THE WORSE CASE SCENARIO.
EXTENDED DISCUSSION...
A LARGE AREA OF HIGH PRESSURE WILL START TO NOSE INTO THE AREA
FROM THE WEST LATER TUESDAY INTO WEDNESDAY. THIS WILL RESULT IN
GRADUAL CLEARING...CLOUD BASES LIFTING INTO THE MVFR CATEGORY
TUESDAY AFTERNOON AND TUESDAY NIGHT...BEFORE DISSIPATING WEDNESDAY
AND RETURN OF VFR. VFR WILL THEN PREVAIL THROUGH AT LEAST THURSDAY
BEFORE TRENDING DOWN AGAIN FOR THE WEEKEND PER RETURN OF MOISTURE
FROM THE SOUTHWEST. THE NEXT LOW PRESSURE SYSTEM TO AFFECT THE
AREA WILL COME FROM THE SOUTHWEST...LOW PRESSURE DEVELOPING ALONG
THE TEXAS GULF COAST FRIDAY...THEN MOVING NORTHEAST ACROSS THE MID
ATLANTIC REGION FOR THE WEEKEND. THIS SYSTEM LOOKS LIKE IT WILL
PRODUCE A MULTI-DAY PERIOD OF SUB-VFR CONDITIONS...BEGINNING AS
EARLY AS FRIDAY NIGHT...AND LINGERING THROUGH THE WEEKEND.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...SK
NEAR TERM...SK
SHORT TERM...PH
LONG TERM...WERT
AVIATION...PM/SK
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
101 PM EST MON DEC 29 2014
.SYNOPSIS...
A FRONTAL BOUNDARY EXTENDS FROM THE TIDEWATER OF VIRGINIA TO THE
FLORIDA PANHANDLE. ONE WAVE OF LOW PRESSURE WAS PULLING AN AREA OF
WIDESPREAD RAIN INTO EASTERN VIRGINIA AND NORTH CAROLINA. MEANWHILE...
COLDER AIR WILL FILTER INTO THE REGION FROM THE NORTH THIS
AFTERNOON INTO TUESDAY. A WEAK UPPER LEVEL DISTURBANCE IS
EXPECTED TO PASS FROM WEST TO EAST ACROSS THE AREA TONIGHT THROUGH
EARLY TUESDAY. THIS FEATURE MAY BRING A LIGHT WINTRY MIX OF
PRECIPITATION TO PARTS OF THE AREA...WITH THE POTENTIAL FOR AN
INCH OR TWO OF SNOW ACROSS THE VIRGINIA AND WEST VIRGINIA
HIGHLANDS.
&&
.NEAR TERM /THROUGH TUESDAY/...
AS OF 1200 PM EST MONDAY...
SOME UPWARD ADJUSTMENTS TO POPS FOR REST OF AFTERNOO BASED ON
LATEST RADAR TRENDS OF SOME LIGHT DEVELOPMENT ACROSS NORTH
CAROLINA AND SNEAKING INTO SOUTHSIDE VIRGINIA...WHICH HRRR SEEMS
TO HAVE PRETTY GOOD HANDLE ON. LEAVING CHANCE TO LOW LIKELY BACK
IN WEST DUE TO EXPECTED REDEVELOPMENT OF ANOTHER AREA LATER THIS
AFTERNOON AS ISENTROPIC LIFT INCREASES A LITTLE. ALREADY GETTING
SOME DRIZZLE IN MANY MTN AREAS. TEMPS ACROSS THE NORTH AND
NORTHEAST CONTINUE TO SLOWLY DROP AS SHALLOW COLDER AIR SURGES
IN...SO MADE SOME MORE ADJUSTMENTS DOWNWARD THERE AS WELL.
PREV DISCUSSION AS OF 1010 AM EST MONDAY...
MAIN SWATH OF RAIN ASSOCIATED WITH THE MOST RECENT SHORT WAVE TO
PASS ACROSS OUR AREA IS NOW PULLING EAST OF THE FCST AREA THIS
MORNING...WITH LOW CLOUDS AND SOME PATCHY FOG BEHIND IT AS COOL
AIR BEGINS TO FILTER DOWN FROM THE NORTHEAST MOISTURE LINGERS
BEHIND THE AREA OF RAIN. ALL MODELS CONTINUE TO SHOW SOME VERY
LIGHT PRECIP LATER THIS AFTERNOON...MAINLY IN THE MTNS...AS WEAK
ISENTROPIC LIFT MOVES BACK IN AHEAD OF ANOTHER VERY WEAK SHORT
WAVE AND THE LINGERING LOW LEVEL MOISTURE. THINK SOME MODELS MAY
BE OVERDOING THE PRECIP...BUT STILL EXPECT AT LEAST A FEW
HUNDREDTHS...SO AM KEEPING CHC POPS INCREASING TO LOW LIKELY FOR
MANY AREAS IN THE MTNS AS THE AFTERNOON PROGRESSES AND THE WEDGE
SPREADS FARTHER SOUTHWEST SO LIFT INCREASES A LITTLE. FOR
REMAINDER OF AFTERNOON...DROPPING POPS IN EAST TO LOW CHC GIVEN
SOME VERY WEAK ISENTROPIC LIFT MAY CONTINUE OUT THERE...BUT MAY
ULTIMATELY NEED TO DROP POPS THERE LATER.
MADE A FEW TWEAKS TO TEMPS AND WINDS IN THE EAST MAINLY AS SURGE
OF BACK DOOR COOLER AIR ALREADY STARTING...BUT TEMPS INITIALLY
WILL NOT DROP TOO MUCH...UNTIL LATE THIS AFTERNOON AND EVENING.
CERTAINLY WILL NOT RISE THOUGH.
PREV DISCUSSION AS OF 430 AM EST MONDAY...
A COLD FRONT SLIPPED THROUGH THE AREA LATE SUNDAY AND IS NOW
SLOWLY DRIFTING TOWARD THE MID ATLANTIC COAST. A WAVE OF LOW
PRESSURE WAS RIPPLING NORTHEAST ALONG THE FRONT...PROVIDING AREAS
MAINLY SOUTH OF INTERSTATE 81 WITH A WIDESPREAD WETTING RAIN...QPF
OF A THIRD /0.33/ TO TWO THIRDS /0.66/ OF AN INCH. NORTH OF
I-81 THE RAIN WAS NOT SO WIDESPREAD...AND AMOUNTS WILL LIKELY
AVERAGE LESS THAN A TENTH OF AN INCH.
ONCE THE WAVE PASSES LATER THIS MORNING...RAIN SHOULD END OR
TAPER TO DRIZZLE. CLEARING IS NOT ANTICIPATED PER THE DEVELOPMENT
OF NORTHEASTERLY LOW LEVEL WINDS WHICH WILL KEEP CLOUDS BANKED
AGAINST THE EAST SIDE OF THE APPALACHIANS. TEMPERATURES TODAY WILL
BE STEADY OR FALLING...COOLER AIR INFILTRATING THE AREA FROM THE
NORTH OR NORTHEAST AND COUNTERING ANY SORT OF DIURNAL TEMPERATURE
RISE.
WHILE THE MAIN SURFACE FRONT WILL BE WELL TO THE SOUTHEAST OF THE
AREA TONIGHT...THE COMBINATION OF A SECONDARY SURGE OF SHALLOW
COLDER AIR SPILLING DOWN FROM THE NORTH AND NORTHEAST...ALONG WITH
A VERY WEAK UPPER WAVE PASSING OVER FROM THE WEST...WILL CREATE
SOME WEAK ISENTROPIC LIFT OVER THE APPALACHIANS OVERNIGHT AND
LASTING INTO AT LEAST PART OF TUESDAY. MOISTURE IS SHALLOW AND
STRUGGLES TO GET INTO THE ICE CRYSTAL GROWTH ZONE. BOTH THE GFS
AND NAM DO INDICATE A 4 TO 8 HOUR WINDOW LATE TONIGHT INTO EARLY
TUESDAY WHERE SOME ICE CRYSTAL GROWTH TAKES PLACE...BOTH MODELS
SPITTING OUT A TENTH TO TWO TENTHS OF AN INCH OF QPF.
SO THE FORECAST CHALLENGE FOR LATE TONIGHT AND EARLY TUESDAY IS
WEATHER THE PRECIPITATION THAT DEVELOPS FALLS AS DRIZZLE/FREEZING
DRIZZLE...OR AS LIGHT RAIN/LIGHT SNOW. TEMPERATURES TONIGHT AT THE
SURFACE ARE FORECAST TO REACH FREEZING ALONG AND NORTH OF ROUTE
460. THIS WOULD BE THE GENERAL REGION WHERE THE FREEZING DRIZZLE
OR LIGHT SNOW WOULD OCCUR. SOUTH OF 460...THE BOUNDARY LAYER WOULD
MOST LIKELY REMAIN WARM ENOUGH TO SUPPORT DRIZZLE/LIGHT RAIN.
SINCE BOTH THE GFS AND NAM ARE IN GENERAL AGREEMENT THAT A PERIOD
OF LIGHT PRECIP WILL OCCUR...WILL ERR ON THE SIDE OF CAUTION AND
FORECAST AT LEAST A TENTH OF AN INCH OF QPF. FOR AREAS WHERE
TEMPERATURES ARE COLD ENOUGH...MAINLY NORTH OF HIGHWAY 460...THIS
QPF WILL FALL AS LIGHT SNOW OR A MIXTURE OF RAIN AND SNOW. THE
HIGHER ELEVATIONS...HIGHLANDS OF VA/WV...WOULD HAVE THE BEST
CHANCE FOR SEEING SOMETHING THAT WOULD ACCUMULATE...OUR GRIDDED
FORECAST REFLECTING 1-2 INCHES OF SNOW FOR ELEVATIONS ABOVE 2500
FEET. SINCE ACCUMULATIONS ARE NOT EXPECTED TO EXCEED 2 INCHES...NO
HEADLINES PLANNED ATTM.
THE ISENTROPIC LIFT IS FORECAST TO WEAKEN BY TUESDAY
AFTERNOON/EVENING...ANY PRECIPITATION COMING TO AN END. SIMILAR TO
MONDAY...TEMPERATURES TUESDAY WILL EXPERIENCE LITTLE CHANGE
REMAINING NEARLY STEADY THROUGHOUT THE DAY.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
AS OF 400 AM EST MONDAY...
A SHORT WAVE WILL TRACK ACROSS THE OHIO VALLEY TO THE MID ATLANTIC
COAST TUESDAY EVENING. ONCE THIS WAVE PASSES EAST...DRIER COLDER AIR
WILL FILTER INTO THE REGION OVERNIGHT. CONSIDERING THE MILD WEATHER
THE PAST COUPLE OF WEEKS...THIS COLD AIR WILL SEEM LIKE AN ARCTIC
BLAST TO SOME...BUT WE WILL ONLY BE DROPPING TEMPERATURES BACK TO
SEASONAL LEVELS. THE COLD SURFACE HIGH WILL RESIDE BACK OVER THE
PLAINS TUESDAY NIGHT AND SLOWLY MOVE EAST IN ZONAL FLOW THROUGH THE
REST OF THE WEEK. NO PRECIPITATION IS EXPECTED DURING THE PERIOD.
&&
.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
AS OF 300 PM EST SUNDAY...
PERIOD BEGINS WITH SPLIT FLOW AND MODEST TROF OVER THE NORTHEAST
UNITED STATES WITH BROAD WESTERLY FLOW OVER THE FORECAST AREA AND
A CUT OFF LOW IN THE SOUTHWEST UNITED STATES. PATTERN AMPLIFIES BY
FRIDAY WITH DIGGING TROF IN THE CENTRAL UNITED STATES THAT
GENERATES A SURFACE LOW IN THE LEE OF THE ROCKIES.
MODELS SIMILAR IN THE EVOLUTION OF THE LOW THROUGH FRIDAY AND BOTH
THE ECMWF AND GFS TRACK THE LOW FROM THE MISSISSIPPI VALLEY INTO THE
GREAT LAKES. THE ECMWF IS FASTER THAN THE GFS WITH THE LOW AND COLD
FRONT. WPC STAYED CLOSE TO THE TRACK OF THE ECMWF BUT AT A SLOWER
SPEED.
SOME IN-SITU WEDGING MAY BE IN PLACE ON FRIDAY AND FRIDAY NIGHT.
SURFACE AND 850 WARM FRONT LIFT NORTH OF THE FORECAST AREA BY
SATURDAY. NO CLEAR TRENDS FOR PRECIPITATION TYPE ALTHOUGH WARMING
ALOFT SUPPORTS FREEZING RAIN/SLEET...DEPENDING ON HOW COLD
TEMPERATURES AREA AT THE SURFACE.
BEST MOISTURE AND LIFT WILL BE SATURDAY AND SATURDAY NIGHT JUST
AHEAD OF THE COLD FRONT. AT THIS TIME EXPECTING THE FRONT TO COME
THROUGH THE FORECAST AREA EARLY SUNDAY. THIS TIMING IS LIKELY TO
CHANGE AS THE SYSTEM GOES THROUGH A FEW MORE FORECAST CYCLES IN THE
MODELS.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
AS OF 100 PM EST MONDAY...
IFR TO LIFR CONDITIONS EXPECTED TO CONTINUE AT ALL AIRPORTS
THROUGH AT LEAST TONIGHT...AND FOR WESTERN AIRPORTS EVEN INTO
EARLY PART OF TUESDAY...UNDER THE INFLUENCE OF COLD AIR DAMMING
WHICH IS ONLY STRENGTHENING WITH TIME. KLYH CURRENTLY MVFR BUT
EXPECTED TO DROP TO IFR BY EARLY EVENING IF NOT SOONER. LOW
CONFIDENCE IN WHEN CONDITIONS MAY BEGIN TO BREAK OUT AND LIFT
EARLY TUESDAY...AND MAY HAPPEN AT KBLF SOONER THAN TAF CURRENTLY
INDICATES. MORE CONFIDENT THAT KROA AND KLYH WILL IMPROVE TO AT
LEAST MVFR DURING TUESDAY MORNING AS DRIER AIR CONTINUES TO FILTER
DOWN FROM NORTH...AND EVENTUALLY KDAN AS WELL BEFORE 18Z.
IN ADDITION...ALL AIRPORTS EXCEPT FOR KDAN SHOULD SEE SOME VERY
LIGHT RAIN CHANGE TO LIGHT SNOW AFTER MIDNIGHT...BUT NOT EXPECTED
TO STICK MUCH AT ALL EXCEPT FOR THE HIGHER ELEVATION AIRPORTS SUCH
AS KLWB...AND KBCB. NOT SURE IT WILL BE COLD ENOUGH TO REALLY
STICK AT KBLF AND KROA OR KLYH. KDAN LIKELY WILL NOT EVEN SEE
CHANGEOVER. IN ANY CASE...SNOW AMOUNTS WOULD ONLY APPROACH AN INCH
IN THE WORSE CASE SCENARIO.
EXTENDED DISCUSSION...
A LARGE AREA OF HIGH PRESSURE WILL START TO NOSE INTO THE AREA
FROM THE WEST LATER TUESDAY INTO WEDNESDAY. THIS WILL RESULT IN
GRADUAL CLEARING...CLOUD BASES LIFTING INTO THE MVFR CATEGORY
TUESDAY AFTERNOON AND TUESDAY NIGHT...BEFORE DISSIPATING WEDNESDAY
AND RETURN OF VFR. VFR WILL THEN PREVAIL THROUGH AT LEAST THURSDAY
BEFORE TRENDING DOWN AGAIN FOR THE WEEKEND PER RETURN OF MOISTURE
FROM THE SOUTHWEST. THE NEXT LOW PRESSURE SYSTEM TO AFFECT THE
AREA WILL COME FROM THE SOUTHWEST...LOW PRESSURE DEVELOPING ALONG
THE TEXAS GULF COAST FRIDAY...THEN MOVING NORTHEAST ACROSS THE MID
ATLANTIC REGION FOR THE WEEKEND. THIS SYSTEM LOOKS LIKE IT WILL
PRODUCE A MULTI-DAY PERIOD OF SUB-VFR CONDITIONS...BEGINNING AS
EARLY AS FRIDAY NIGHT...AND LINGERING THROUGH THE WEEKEND.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...JH/SK
NEAR TERM...PM/SK
SHORT TERM...RCS
LONG TERM...AMS
AVIATION...PM/SK
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1105 PM CST SUN DEC 28 2014
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 200 PM CST SUN DEC 28 2014
CURRENTLY AS OF 20Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED A STRONG SHORTWAVE DROPPING SOUTH THROUGH THE NORTHWESTERN
U.S. AND BRITISH COLUMBIA...A COLLECTION OF WEAK SHORTWAVES OVER
WYOMING AND NEBRASKA AND AN UPPER LOW OVER NORTHERN ONTARIO. DESPITE
A MAINLY ZONAL FLOW COMING ACROSS THE FORECAST AREA...A COLD FRONT
WAS EVIDENT AT THE SURFACE DROPPING SOUTH INTO THE AREA. THIS FRONT
EXTENDED FROM NORTHERN LOWER MI TO LA CROSSE TO SIOUX CITY IA. LOW
CLOUDS WITH A FEW FLURRIES WERE EVIDENT IN A 100 MILE WIDTH ZONE
BEHIND THE FRONT...WHILE SKIES WERE MAINLY SUNNY AHEAD OF IT. 925MB
TEMPS OF -6 TO -10C AND SUN HAS ALLOWED TEMPERATURES TO MOSTLY CLIMB
INTO THE 20S WITH A FEW NEAR 30 READINGS IN FAR SOUTHWEST WISCONSIN.
COLDEST READINGS HAVE BEEN OVER THE NORTHWEST 1/3 OF THE AREA WITH
MORE SNOW AND BEING FIRST TO EXPERIENCE THE FROPA. MUCH COLDER AIR
TRYING TO SINK SOUTH BEHIND THE FRONT WITH 925MB TEMPS IN THE -15 TO
-20C RANGE OVER MUCH OF NORTH DAKOTA INTO NORTHERN MN.
THE MAIN FEATURE OF INTEREST FOR THE SHORT TERM IS THE COLLECTION OF
WEAK SHORTWAVES OVER WYOMING AND NEBRASKA. MODELS ARE IN GOOD
AGREEMENT BRINGING THESE SHORTWAVES ACROSS IOWA AND SOUTHERN
PORTIONS OF THE FORECAST AREA LATE TONIGHT INTO MONDAY MORNING. WITH
THESE SHORTWAVES COMES INCREASING MID LEVEL FRONTOGENESIS...MOSTLY
IN THE WAKE OF THE CURRENT COLD FRONT DROPPING SOUTH THROUGH THE
FORECAST AREA. PROBLEM IS THAT AT THE TIME OF THE BEST MID LEVEL
LIFT...THERE IS ENOUGH DRY AIR BELOW THE MID CLOUDS TO ABSORB MUCH
OF THE SNOW PRODUCTION. WHEN THAT DRY AIR MOSTLY SATURATES...THE
LIFT IS GONE. THEREFORE...A MENTION OF FLURRIES AS THE PREVIOUS
FORECAST HAD SEEMS REASONABLE. MOST 28.12Z GUIDANCE OF QPF CONTINUES
TO PRODUCE A DRY FORECAST TOO.
COLD ADVECTION BEHIND THE COLD FRONT PASSAGE WILL BE THE MAIN FACTOR
IN DROPPING TEMPERATURES TONIGHT...SINCE CLOUDS SHOULD BE IN PLACE
FOR MOST LOCATIONS. 925MB TEMPS FALL TO -10C SOUTH TO -15C NORTH...
WHICH SHOULD ALLOW TEMPERATURES TO DROP INTO THE SINGLE DIGITS NORTH
TO NEAR 20 SOUTH. THE COLDEST READINGS ARE EXPECTED IN TAYLOR/CLARK
COUNTIES WHERE SOME CLEARING IS POSSIBLE THIS EVENING BEFORE
MID/HIGH CLOUDS OVERSPREAD. FURTHER 925MB TEMP COOLING TAKES PLACE
ON MONDAY DUE TO PERSISTENT NORTHERLY FLOW. READINGS DROP TO -13C
SOUTH TO -17C NORTH...WHICH MEANS HIGHS WILL STRUGGLE TO CLIMB MUCH
THAN A FEW DEGREES ABOVE THE LOWS TONIGHT.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 200 PM CST SUN DEC 28 2014
THE MAIN STORY MONDAY NIGHT THROUGH TUESDAY NIGHT IS THE COLD. ALL
MODELS CONTINUE TO DROP A 1050-1060MB HIGH SOUTHWARD ALONG THE LEE
SIDE OF THE ROCKIES DURING THIS TIME...WITH COLD ADVECTION
DOWNSTREAM OF THE HIGH OVER THE FORECAST AREA. 925MB TEMPS FALL TO
-16 TO -19C BY 12Z TUESDAY AND TO AROUND -20C BY 06Z WEDNESDAY. MUCH
OF THE TIME PERIOD SHOULD BE MOSTLY CLEAR...OUTSIDE OF SOME PASSING
CLOUDS TUESDAY AFTERNOON AND EVENING ASSOCIATED WITH A SHORTWAVE
TROUGH OF ARCTIC ORIGIN MOVING THROUGH. THE SOUTHEAST HALF OF THE
FORECAST AREA WILL STAY WARMER DUE TO THE FACT OF NO SNOW ON THE
GROUND...BUT STILL EXPECT CHILLY READINGS...ESPECIALLY TUESDAY NIGHT
WITH THE COLDEST AIR IN PLACE. A PERSISTENT NORTHWEST BREEZE SHOULD
EXIST SINCE WE ARE NOT UNDER THE CENTER OF THE HIGH...THEREFORE...
WIND CHILLS BECOME A FACTOR. ADVISORIES ARE LIKELY TO BE NEEDED BOTH
NIGHTS...PARTICULARLY OVER NORTH CENTRAL WI AND POSSIBLY PORTIONS OF
SOUTHEAST MN AND NORTHEAST IA TOO.
SOME MODERATION TAKES PLACE WEDNESDAY INTO THURSDAY / NEW YEARS EVE
AND DAY / IN RESPONSE TO A POTENT SHORTWAVE TROUGH DIGGING INTO
NORTHERN ONTARIO AND LAKE SUPERIOR. HOWEVER...THIS MODERATION TAKES
PLACE AT THE EXPENSE OF HIGHER WINDS...WHICH MEANS A PERSISTENT WIND
CHILL FACTOR. FIRST...THE WESTERLY WINDS ADVECT DOWNSLOPED AIR OFF
THE ROCKIES TOWARDS THE FORECAST AREA...BOOSTING 925MB TEMPS TO
AROUND -14C BY 00Z THU AND -8 TO -10C BY 00Z FRI. THESE READINGS
SHOULD HELP BRING HIGHS BACK UP INTO THE TEENS ON WEDNESDAY AND
MOSTLY INTO THE 20S ON THURSDAY. NOW REGARDING THE WINDS...925MB
SPEEDS ARE PROGGED TO INCREASE TO THE 35 TO 45 KT RANGE AT 00Z THU
BEFORE RELAXING SOME FOR DURING THE DAY THURSDAY. WITH PLENTY OF SUN
ON WEDNESDAY...WE SHOULD SEE SOME GOOD MIXING OF THOSE WINDS. RIGHT
NOW IT APPEARS GUSTS MAY TOP OUT AROUND 30 KT...HIGHEST IN SOUTHEAST
MN...BUT WORTH MONITORING OVER THE NEXT FEW DAYS TO SEE IF THESE END
UP HIGHER. SOMETHING ELSE TO MONITOR ON THURSDAY IS POSSIBLE LIGHT
SNOW AS A COLD FRONT AND SHORTWAVE TROUGH DROP THROUGH THE NORTHERN
PORTION OF THE FORECAST AREA. HAVE ADDED SOME CHANCE POPS TO
LOCATIONS NORTH OF I-90.
FOR FRIDAY INTO SATURDAY...WE NEED TO WATCH CLOSELY THE EVOLUTION
AND TRACK OF AN UPPER LOW THAT COMES OUT OF THE SOUTHWESTERN U.S..
THIS UPPER LOW...FORMED BY THE CURRENT STRONG SHORTWAVE DIVING SOUTH
THROUGH THE NORTHWESTERN U.S....IS PRESENTLY PROGGED TO GET LIFTED
THROUGH MISSOURI AND INTO LOWER MI ON SATURDAY. SOME WARM ADVECTION
SNOW COULD BEGIN TO APPROACH THE REGION AS EARLY AS LATE FRIDAY WELL
DOWNSTREAM OF THIS UPPER LOW...OR FROM A FRONTOGENESIS BAND TRACKING
ACROSS THE NORTHERN U.S.. HOWEVER...FRIDAY NIGHT INTO SATURDAY SEEM
TO BE THE BETTER CHANCES IN SEEING A COLD CONVEYOR BELT BAND OF SNOW
TRACK ACROSS THE FORECAST AREA FROM THE UPPER LOW. IF THIS SYSTEM
TRACKS FARTHER NORTHWEST...MAY END UP WITH AN ADVISORY LEVEL SNOW.
NOTE THAT THE 28.12Z ECMWF/UKMET/CANADIAN PRESENT A MUCH SLOWER IDEA
WITH THE UPPER LOW...RESULTING IN A MUCH DRIER SCENARIO...THUS
PLENTY OF UNCERTAINTY AND ONLY 30-40 PERCENT PRECIPITATION CHANCES.
POST THE SATURDAY SYSTEM...A STRONG SURGE OF ARCTIC AIR LOOKS POISED
TO IMPACT THE REGION FOR SUNDAY INTO EARLY NEXT WEEK. IT COULD BE
NEARLY AS COLD AS THE JANUARY 5-7TH 2014 ARCTIC OUTBREAK...AND JUST
HAPPENS TO BE THE SAME DATES. THE 28.12Z MODEL CYCLE DEPICTS THE GFS
COLDER WHILE THE ECMWF WAS WARMER AND A BIT MORE DELAYED...WAITING
UNTIL MONDAY TO DRIVE THE COLD AIR IN. NEEDLESS TO SAY...STAY
TUNED.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1105 PM CST SUN DEC 28 2014
AREAS OF 1 KFT CLOUDS HANGING ACROSS SOUTHWEST MN LATE THIS
EVENING...BUT MESO MODELS ARE ADAMANT THAT THESE WILL STAY WEST OF
KRST. INSTEAD...HIGH LEVEL CLOUDS ARE EXPECTED TO CONTINUE TO FILTER
ACROSS THE REGION TONIGHT/MONDAY...STAYING VFR.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM....AJ
AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
953 PM PST TUE DEC 30 2014
...A COLD AND WINDY END TO 2014...
.SYNOPSIS...STRONG AND GUSTY NORTH TO NORTHEAST WINDS WILL
CONTINUE ACROSS THE SAN FRANCISCO BAY AREA THROUGH WEDNESDAY
MORNING BUT NOT AS STRONG AS TUESDAY AFTERNOON. A COLD AIRMASS
IN PLACE WILL RESULT IN LOW WIND CHILLS TONIGHT AND THEN THE
COLDEST TEMPERATURES OF THE SEASON WEDNESDAY NIGHT AS WINDS SUBSIDE.
TEMPERATURES WARM LATE IN THE WEEK INTO THE WEEKEND.
&&
.DISCUSSION...AS OF 9:00 PM PST TUESDAY...DEEP UPPER LEVEL LOW
OVER SOUTHERN CALIFORNIA IS BRINGING A COLD AIRMASS WITH STRONG
NORTH TO NORTHEAST FLOW OVER THE AREA. WINDS INCREASED
DRAMATICALLY DURING THE LATE MORNING AND AFTERNOON HOURS JUST
AFTER THE TROUGH AXIS PASSED WHEN VERTICAL MIXING WAS GREATEST
ALLOWING THE STRONG WINDS ALOFT TO MIX TO THE SURFACE. PEAK WIND
GUSTS WERE IN THE 40-45 MPH RANGE AROUND THE SFO BAY AREA WHILE
PEAK WINDS OVER 60 MPH WERE REPORTED IN THE EAST BAY HILLS.
LATEST MODELS SHOW 925 MB WINDS IN THE 35-40 KT RANGE THROUGH THE
EVENING. THIS WILL KEEP STRONG WINDS GOING IN THE NORTH AND EAST
BAY HILLS AND SANTA CRUZ MOUNTAINS THROUGH WEDNESDAY MORNING. WINDS
AT THE LOWER ELEVATIONS WILL NOT BE AS STRONG AS THEY WERE THIS AFTERNOON
AS THE LOW IS MOVING SOUTHEAST AWAY FROM THE DISTRICT AND THE
VERTICAL MIXING IS WEAKER...HOWEVER WIND GUSTS IN THE 30-35 MPH
RANGE CAN STILL BE EXPECTED THROUGH THE NIGHT IN THE LOWER
ELEVATIONS OF THE SFO BAY AREA. THE WIND ADVISORY WILL BE
CONTINUED THROUGH WEDNESDAY MORNING.
WINDS WILL DECREASE WEDNESDAY AS THE LOW CONTINUES TO MOVE OFF.
THIS WILL ALLOW FOR COLDER TEMPERATURES WEDNESDAY NIGHT.
TEMPERATURES ARE EXPECTED TO DROP BELOW FREEZING IN MANY INLAND
VALLEY LOCATIONS WITH MID TO UPPER 30S AROUND THE URBAN SFO BAY
AREA AND MRY BAY AREA. A FREEZE WARNING MAY BE ISSUED FOR WEDNESDAY
NIGHT FOR THE INLAND AND MOUNTAIN AREAS. A FROST ADVISORY MAY BE
NEEDED FOR PARTS OF THE URBAN SFO BAY AREA AND THE MRY BAY AREA.
FREEZE WARNINGS AND FROST ADVISORIES MAY BE NEEDED AGAIN THURSDAY
NIGHT. THE AIRMASS ALOFT WILL BE WARMER AS 850 MB TEMPERATURES IS
FORECAST TO BE ABOUT +6C BUT THE AIR WILL BE VERY DRY ALLOWING FOR
BETTER RADIATIONAL COOLING.
TEMPERATURES WILL SLOWLY WARM THIS WEEKEND AS AN UPPER LEVEL RIDGE
MOVES OVER THE AREA FROM THE WEST. THE RIDGE WILL HOLD THROUGH
EARLY NEXT WEEK. MEDIUM RANGE MODELS ARE HINTING AT A CHANCE OF
RAIN THE MIDDLE OF NEXT WEEK. THE LATEST GFS AND ECMWF ARE
SHOWING THIS AND EVEN THE LATEST RUN OF THE CANADIAN IS ON BOARD
NOW. SO HOPES ARE RISING THAT WE MAY SEE SOME RAIN AROUND THE
MIDDLE OF NEXT WEEK BUT IT WONT BE A LOT OF RAIN.
&&
.AVIATION...AS OF 10 PM PST TUESDAY...AN ENERGETIC WINDSTORM WILL
CONTINUE TO BRING GUSTY NORTH WINDS WHILE DESCENDING INTO SOUTHERN
CALIFORNIA LATE THIS EVENING. AIRPORTS ACROSS THE REGION HAVE
REPORTED SIGNIFIANT DECLINES IN WIND SPEEDS WITH THE NOTABLE
EXCEPTION OF SFO... WHICH CONTINUES TO GUST TO AROUND 40KTS.
MODELS HAVE STRUGGLED WITH WIND SPEEDS AND TIMING SO FAR...
HOWEVER THE HRRR HAS BEEN CONSISTENT IN WEAKENING NEAR SURFACE
WINDS BY 07Z SINCE THIS AFTERNOON. WINDS AND GUSTS WILL DIMINISH
THROUGH THE NIGHT.
VICINITY OF KSFO...VFR. NORTH WINDS WILL REMAIN GUSTY THROUGH THE
NIGHT AT KSFO. STRONGEST WINDS SHOULD DIMINISH AFTER 07Z.
KSFO BRIDGE APPROACH...SIMILAR TO KSFO.
MONTEREY BAY AREA TERMINALS...VFR.
&&
.MARINE...AS OF 9 PM PST TUESDAY...STRONG NORTHEAST WINDS WILL
PERSIST THROUGH THE REMAINDER OF THE EVENING BEFORE TAPERING LATE
TONIGHT AND EARLY WEDNESDAY. EXPECT FRESH SWELL WITH CHAOTIC SEAS
AND HAZARDOUS CONDITIONS ALONG THE COAST WITH THE STRONG OFFSHORE
WINDS. DIMINISHING NW SWELL THROUGH THE FORECAST PERIOD.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.TNGT...WIND ADVISORY...ENTIRE SFO BAY AREA AND SANTA CRUZ COUNTY
SCA...SF BAY SOUTH OF THE BAY BRIDGE
SCA...PT ARENA TO PT REYES 0-10 NM
SCA...PT REYES TO PIGEON PT 0-10 NM
SCA...PIGEON PT TO PT PINOS 0-10 NM
SCA...PT ARENA TO PT REYES 10-60 NM
SCA...PT PINOS TO PT PIEDRAS BLANCAS 0-10 NM UNTIL 4 AM
SCA...PT REYES TO PIGEON PT 10-60 NM
SCA...PIGEON PT TO PT PINOS 10-60 NM
SCA...PT PINOS TO PT PIEDRAS BLANCAS 10-60 NM
SCA...MONTEREY BAY UNTIL 3 AM
GLW...SF BAY NORTH OF THE BAY BRIDGE
&&
$$
PUBLIC FORECAST: W PI
AVIATION: DRP
MARINE: MM
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AREA FORECAST DISCUSSION
NWS MARQUETTE MI
359 AM EST WED DEC 31 2014
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 427 PM EST TUE DEC 30 2014
WV IMAGERY AND RUC ANALYSIS INDICATED A PROMINENT MID/UPPER LEVEL
RIDGE FROM THE ERN PACIFIC INTO BC AND A TROUGH OVER NE CANADA
RESULTING IN NNW FLOW TOWARD NRN ONTARIO AND THE NRN LAKES. A
SHORTWAVE TROUGH AXIS EXTENDED FROM JAMES BAY INTO SE NORTH DAKOTA.
WITH ONLY WEAK FORCING AND LITTLE MOISTURE AVAILABLE...NO PCPN WAS
ASSOCIATED WITH THIS FEATURE. FURTHER UPSTREAM...A STRONGER SHRTWV
WAS MOVING THROUGH NRN SASK/MANITOBA. AT THE SFC...W TO WNW FLOW
PREVAILED ACROSS UPPER MI AND LAKE SUPERIOR AS 1048 MB HIGH PRES
CONTINUES TO SINK THROUGH THE NRN AND CNTRL PLAINS. EVEN WITH 850 MB
TEMPS NEAR -23C...SATELLITE/RADAR INDICATED ONLY LIGHT TO MODERATE
LES INTO NW UPPER MI AND EAST OF MUNISING AS INVERSION HEIGHTS
REMAINED NEAR 4K FT WITH VERY DRY AIR UPSTREAM.
TONIGHT...EXPECT WINDS TO GRADUALLY BACK TO SW AHEAD OF THE
SASK/MANITOBA SHRTWV WHICH WILL PUSH THE LES MOSTLY OFFSHORE.
HOWEVER...ADDITIONAL SNOWFALL AMOUNTS OF 1 TO 3 INCHES NW(KEWEENAW
AND 2 TO 4 INCHES NE (NE OF P53) ARE POSSIBLE. TEMPS FALLING OFF
INTO THE -7F TO -12F RANGE AND WINDS NEAR 10 MPH WILL DROP WIND
CHILLS INTO THE -20 TO -33 RANGE OVER THE INTERIOR WRN HALF WHERE
WIND CHILL ADVISORIES WILL REMAIN IN EFFECT.
WEDNESDAY...AS THE SHRTWV MOVES THROUGH THE NRN LAKES AND DRAGS A
WEAK TROUGH THE AREA...WINDS WILL VEER AGAIN FROM SW TO W BY
AFTERNOON. THIS WILL BRING THE LES INTO THE NRN KEWEENAW BY MIDDAY
AND INTO MUCH OF THE REST OF THE PENINSULA BY MID TO LATE AFTERNOON.
THE COMBINATION OF THE LES AND WIND GUSTS OVER 40 MPH WILL LEAD TO
VERY POOR VSBY WHICH WILL LINGER INTO THE EVENING...PROMPTING THE
ISSUANCE OF AN LES ADVY. ALTHOUGH THERE WILL BE A PERIOD OF DEEPER
MOISTURE THAT SHOULD INTENSIFY LES...THE SHIFTING WIND DIRECTIONS
SHOULD LIMIT OVERALL AMOUNTS TO THE 1 TO 3 INCH RANGE BY EVENING.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 427 PM EST TUE DEC 30 2014
UPPER AIR PATTERN STARTS OUT WITH TROUGHING ANCHORED OVER HUDSON BAY
AND ANOTHER MORE COMPACT TROUGH OVER DESERT SOUTHWEST OF CONUS. ONLY
RIDGING OF NOTE IS OVER THE EASTERN PACIFIC OCEAN INTO FAR WESTERN
CANADA. ATTENTION THIS WEEKEND WILL BE ON THE SOUTHWEST CONUS TROUGH.
MODELS CONTINUE TO FAVOR IDEA THAT AS STRONG JET ENERGY ADVANCES
AHEAD OF TROUGH...IT WILL EMERGE OVER THE SOUTHERN PLAINS ON
SATURDAY AND LIFT OVER THE GREAT LAKES ON SUNDAY. MEANWHILE...ANOTHER
SHORTWAVE WITHIN THE BASE OF LARGER TROUGHING OVER EASTERN CANADA
WILL WORK OVER THE UPPER GREAT LAKES. ONE OR BOTH OF THESE FEATURES
MAY BRING WIDESPREAD SNOW TO UPR MICHIGAN FRIDAY NIGHT THROUGH
SATURDAY NIGHT. THERE IS POTENTIAL THAT THE TWO FEATURES COULD
PHASE...THOUGH THAT IS NOT CERTAIN...AND THAT WOULD RESULT IN
GREATEST CHANCE OF SEEING HIGHER END SNOW EVENT.
NO MATTER HOW IT SHAKES OUT...THERE ARE INDICATIONS VERY CHILLY
AIRMASS...EVEN COLDER THAN ONE CURRENTLY AFFECTING THE REGION...WILL
SETTLE OVER UPR GREAT LAKES BY EARLY NEXT WEEK. BEYOND END OF
EXTENDED THERE ARE SIGNALS THAT RIDGE OVER EAST PACIFIC BREAKS DOWN
AND MORE MILD AIR RETURNS TO MUCH OF THE CONUS. PATTERN SHIFT THE
CFSV2 HAS BEEN SHOWING FOR A WHILE NOW. THUS...OVERALL IT DOES NOT
APPEAR THAT THE UPCOMING COLD WILL BE THAT LONG LASTING.
INTIALLY THE MAIN ISSUE WILL BE THE ONGOING WEST FLOW LAKE EFFECT
AND BLOWING SNOW WITH POOR VSBY OVER THE KEWEENAW. DECENT AGREEMENT
THAT SHORTWAVE DROPPING WNW-ESE OVER LK SUPERIOR AND UPR MICHIGAN
WEDNESDAY EVENING WITH LEADING SFC TROUGH AND ENHANCED CONVERGENCE
AND ADDITIONAL MOISTURE WILL RESULT IN A A BRIEF PERIOD OF MODERATE
TO HEAVY LES. WIND CORE MAX AT 950-925MB OVER 40 KTS WILL BE EASING
BY WEDNESDAY EVENING...BUT MIXED LAYER WINDS UP TO 40 KTS WILL STILL
RESULT IN STRONG/GUSTY WINDS OVER 30 MPH AND BLSN/POOR VSBY.
SOUNDINGS SHOW MARGINAL MOISTURE AND INSTABILITY FOR SIGNIFICANT LES
THOUGH AFTER THE TROUGH PASSAGE WITH INVERSIONS PEAKING AT 5-7 KFT
AGL WEDNESDAY EVENING AND LAKE INDUCED EQL NOT MUCH HIGHER THAN
THAT. MAJORITY OF THE MOIST LAYER IS WITHIN THE DGZ BUT STRONG WINDS
WILL LIKELY CUT DOWN SLR/S. POOR VSBY WILL BE THE BIGGER STORY
COMPARED TO SNOW AMOUNTS. AFTER COORDINATING WITH SHORT TERM
FORECASTER... DECIDED TO GO WITH LAKE EFFECT SNOW ADVISORY FOR SNOW
AND BLOWING SNOW WEDNESDAY AFTN THROUGH EARLY AFTERNOON ON NEW YEARS
DAY. WILL MENTION OCCASIONAL WHITEOUT CONDITIONS IN THE WSW
STATEMENT.
LAKE EFFECT AND BLOWING SNOW BECOME FACTOR LATE WEDNESDAY NIGHT INTO
THURSDAY FOR AREAS FAVORED BY WNW WINDS...ONTONAGON COUNTY OVER THE
WEST AND IN THE SNOW BELTS OF EASTERN HALF OF UPR MICHIGAN. LOOKING
AT ONLY A PURE LES SETUP AS SOUNDINGS SHOW SHARP DRYING ABOVE 8KFT.
TEMPS AT TOP OF INVERSION BLO -20C LEAD TO MARGINAL INSTABILITY GIVEN
WATER TEMPS 2-3C. MOST OF LAKE CONVECTIVE LAYER WILL BE IN THE DGZ
AND WINDS WILL BE DIMINISHING...SO FLUFF FACTOR WILL PLAY MORE OF A
ROLE. OVERALL...ADVY SNOW AMOUNTS SEEM POSSIBLE INTO NEW YEARS DAY
FOR THE WNW FLOW AREAS.
LAKE EFFECT LINGERS FOR WNW FLOW AREAS INTO FRIDAY...BUT WILL
CONTINUE TO DIMINISH AS HIGH PRESSURE RIDGE SLIDES ACROSS WESTERN
GREAT LAKES. COLD WILL SLOWLY EASE...THOUGH TEMPS WELL BLO ZERO
EXPECTED THURSDAY NIGHT OVER INTERIOR CNTRL UPR MICHIGAN. INCREASE
OF MID CLOUDS MAY RESULT IN LESS TEMP DROP OVER WEST CWA.
MAIN QUESTION THIS WEEKEND IS HOW MUCH PHASING OCCURS BTWN
APPROACHING NORTHERN STREAM SHORTWAVE TROUGH AND THE UPPER LOW
OPENING UP AS IT LIFTS INTO THE CNTRL PLAINS FM THE SOUTHWEST CONUS.
SINCE MAJORITY OF JET ENERGY REMAINS AHEAD OF THE SOUTHERN STREAM
TROUGH...WOULD EXPECT IT TO STAY FAIRLY PROGRESSIVE AND HAVE LESS
CHANCE OF PHASING WITH NORTHERN STREAM SYSTEM. EVEN SO...THE
NORTHERN STREAM SHORTWAVE ALONG WITH INCREASING NNE-NNW FLOW WITH
H85 TEMPS BLO -12C SATURDAY NIGHT INTO SUNDAY MAY LEAD TO SEVERAL
INCHES OF SNOW. BEST SHOT OF SYNOPTIC SNOW WOULD BE OVER THE SOUTH
AND EAST CWA WHILE THE GREATEST CHANCE FOR LAKE ENHANCEMENT WOULD BE
OVER THE WEST AND NORTH CENTRAL CWA. TIGHT PRESSURE GRADIENT RESULTS
IN GUSTY WINDS AND BLOWING SNOW AS WELL. MODEL TRENDS FOR THIS
SYSTEM ARE VARIABLE WITH EARLIER RUNS A FEW DAYS AGO SHOWING A
WRAPPED UP SYSTEM AND RECENT RUNS BACKING AWAY FM THAT. LATEST RUNS
SEEM TO BE TRYING TO COME BACK TO AT LEAST A FARTHER WEST TRACK TO
THE SOUTHERN STREAM SYSTEM IF NOT A MORE PHASED SYSTEM. SYSTEM BEARS
WATCHING AS IT COULD RESULT IN SOME HEADLINES.
BEHIND THE SYSTEM...LOOKS VERY COLD WITH H85 TEMPS DOWN TO -28C BY
NEXT MONDAY. INCREASED POPS FOR LAKE EFFECT IN WNW-W FLOW AREAS.
MAJORITY OF LAKE CONVECTIVE LAYER IS AT TEMPS BLO -20C...SO SLR/S
WILL BE LOW AND MAIN PROBLEM COULD BE POOR VSBY. COULD ALSO HAVE
WIND CHILL ISSUES FOR THE FIRST DAY BACK TO SCHOOL AFTER WINTER
VACATION.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1156 PM EST TUE DEC 30 2014
LAKE EFFECT SNOW WILL FAVOR PERSISTENT MVFR CIGS AND IFR/LIFR VSBY
AT CMX THROUGH THE PERIOD. GUSTY WINDS INTO WED MORNING WILL ALSO
REDUCE VSBY WITH BLSN. AT SAW AND IWD...VFR CONDITIONS WILL CONTINUE
THROUGH THE PERIOD. WILL GET GUSTY AT ALL SITES LATE TONIGHT THROUGH
WED.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 358 AM EST WED DEC 31 2014
LAKE SUPERIOR WILL BE STUCK BETWEEN VERY STRONG HIGH PRESSURE ACROSS
THE S PLAINS AND A DEEP HUDSON BAY LOW TODAY. GALES OF 35-45KTS WILL
CONTINUE BEFORE SLOWLY DIMINISHING TO 35KTS LATE TONIGHT INTO
THURSDAY MORNING OUT OF THE W-NW. GIVEN PLENTY OF COLD AIR...AND
STRONG WINDS...HEAVY FREEZING SPRAY WILL ALSO BE A CONCERN INTO
THURSDAY.
LOOK FOR THE TROUGH OVER LAKE SUPERIOR TO DEEPEN TONIGHT THROUGH
THURSDAY. THE HUDSON BAY LOW WILL SHIFT AND WEAKEN ACROSS N QUEBEC
THURSDAY NIGHT...ALLOWING THE TROUGH ACROSS LAKE SUPERIOR TO WEAKEN
AS WELL. HIGH PRESSURE SINKING ACROSS MANITOBA AND MINNESOTA
THURSDAY NIGHT WILL BUILD RIDGE ACROSS LAKE SUPERIOR ON FRIDAY AS IT
PROGRESSES ACROSS THE REMAINDER OF THE GREAT LAKES. A WEAK TROUGH
WILL LIKELY LINGER ACROSS MAINLY E LAKE SUPERIOR DURING THIS TIME.
EXPECT A LOW NEAR MONTANA ON FRIDAY TO TRACK ACROSS THE N AND
CENTRAL PLAINS SATURDAY MORNING...AND THE MID MISSISSIPPI VALLEY
SATURDAY AFTERNOON...BEFORE DEEPENING NORTHEASTWARD ACROSS THE LOWER
GREAT LAKES AND QUEBEC LATE SATURDAY NIGHT INTO SUNDAY. THIS WILL
BRING A TROUGH OF SATURDAY NIGHT INTO SUNDAY ACROSS LAKE
SUPERIOR...ALONG WITH THE RETURN OF N-NW GALES OF 35-40KTS. HEAVY
FREEZING SPRAY WILL ALSO MAKE A RETURN ACROSS MUCH OF LAKE SUPERIOR.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WIND CHILL ADVISORY UNTIL 10 AM EST /9 AM CST/ THIS MORNING FOR
MIZ002-004-005-009>012-084.
LAKE EFFECT SNOW ADVISORY FROM 1 PM THIS AFTERNOON TO 1 PM EST
THURSDAY FOR MIZ001-003.
LAKESHORE FLOOD ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR MIZ001-
003.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 1 PM EST /NOON CST/ THURSDAY
FOR LSZ240>251-263>267.
GALE WARNING UNTIL 1 PM EST THURSDAY FOR LSZ244-245-264>267.
GALE WARNING FROM 7 PM THIS EVENING TO 1 PM EST THURSDAY FOR
LSZ249>251.
GALE WARNING FROM 10 AM THIS MORNING TO 1 PM EST THURSDAY FOR
LSZ246>248.
GALE WARNING UNTIL 7 AM EST /6 AM CST/ THURSDAY FOR LSZ162-
241>243-263.
HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST /6 AM CST/ THURSDAY
FOR LSZ162.
LAKE MICHIGAN...
HEAVY FREEZING SPRAY WARNING FROM 10 AM THIS MORNING TO 1 PM EST
THURSDAY FOR LMZ221-248-250.
GALE WARNING FROM 10 AM THIS MORNING TO 1 AM EST THURSDAY FOR
LMZ221-250.
&&
$$
SHORT TERM...JLB
LONG TERM...JLA
AVIATION...07
MARINE...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1156 PM EST TUE DEC 30 2014
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 427 PM EST TUE DEC 30 2014
WV IMAGERY AND RUC ANALYSIS INDICATED A PROMINENT MID/UPPER LEVEL
RIDGE FROM THE ERN PACIFIC INTO BC AND A TROUGH OVER NE CANADA
RESULTING IN NNW FLOW TOWARD NRN ONTARIO AND THE NRN LAKES. A
SHORTWAVE TROUGH AXIS EXTENDED FROM JAMES BAY INTO SE NORTH DAKOTA.
WITH ONLY WEAK FORCING AND LITTLE MOISTURE AVAILABLE...NO PCPN WAS
ASSOCIATED WITH THIS FEATURE. FURTHER UPSTREAM...A STRONGER SHRTWV
WAS MOVING THROUGH NRN SASK/MANITOBA. AT THE SFC...W TO WNW FLOW
PREVAILED ACROSS UPPER MI AND LAKE SUPERIOR AS 1048 MB HIGH PRES
CONTINUES TO SINK THROUGH THE NRN AND CNTRL PLAINS. EVEN WITH 850 MB
TEMPS NEAR -23C...SATELLITE/RADAR INDICATED ONLY LIGHT TO MODERATE
LES INTO NW UPPER MI AND EAST OF MUNISING AS INVERSION HEIGHTS
REMAINED NEAR 4K FT WITH VERY DRY AIR UPSTREAM.
TONIGHT...EXPECT WINDS TO GRADUALLY BACK TO SW AHEAD OF THE
SASK/MANITOBA SHRTWV WHICH WILL PUSH THE LES MOSTLY OFFSHORE.
HOWEVER...ADDITIONAL SNOWFALL AMOUNTS OF 1 TO 3 INCHES NW(KEWEENAW
AND 2 TO 4 INCHES NE (NE OF P53) ARE POSSIBLE. TEMPS FALLING OFF
INTO THE -7F TO -12F RANGE AND WINDS NEAR 10 MPH WILL DROP WIND
CHILLS INTO THE -20 TO -33 RANGE OVER THE INTERIOR WRN HALF WHERE
WIND CHILL ADVISORIES WILL REMAIN IN EFFECT.
WEDNESDAY...AS THE SHRTWV MOVES THROUGH THE NRN LAKES AND DRAGS A
WEAK TROUGH THE AREA...WINDS WILL VEER AGAIN FROM SW TO W BY
AFTERNOON. THIS WILL BRING THE LES INTO THE NRN KEWEENAW BY MIDDAY
AND INTO MUCH OF THE REST OF THE PENINSULA BY MID TO LATE AFTERNOON.
THE COMBINATION OF THE LES AND WIND GUSTS OVER 40 MPH WILL LEAD TO
VERY POOR VSBY WHICH WILL LINGER INTO THE EVENING...PROMPTING THE
ISSUANCE OF AN LES ADVY. ALTHOUGH THERE WILL BE A PERIOD OF DEEPER
MOISTURE THAT SHOULD INTENSIFY LES...THE SHIFTING WIND DIRECTIONS
SHOULD LIMIT OVERALL AMOUNTS TO THE 1 TO 3 INCH RANGE BY EVENING.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 427 PM EST TUE DEC 30 2014
UPPER AIR PATTERN STARTS OUT WITH TROUGHING ANCHORED OVER HUDSON BAY
AND ANOTHER MORE COMPACT TROUGH OVER DESERT SOUTHWEST OF CONUS. ONLY
RIDGING OF NOTE IS OVER THE EASTERN PACIFIC OCEAN INTO FAR WESTERN
CANADA. ATTENTION THIS WEEKEND WILL BE ON THE SOUTHWEST CONUS TROUGH.
MODELS CONTINUE TO FAVOR IDEA THAT AS STRONG JET ENERGY ADVANCES
AHEAD OF TROUGH...IT WILL EMERGE OVER THE SOUTHERN PLAINS ON
SATURDAY AND LIFT OVER THE GREAT LAKES ON SUNDAY. MEANWHILE...ANOTHER
SHORTWAVE WITHIN THE BASE OF LARGER TROUGHING OVER EASTERN CANADA
WILL WORK OVER THE UPPER GREAT LAKES. ONE OR BOTH OF THESE FEATURES
MAY BRING WIDESPREAD SNOW TO UPR MICHIGAN FRIDAY NIGHT THROUGH
SATURDAY NIGHT. THERE IS POTENTIAL THAT THE TWO FEATURES COULD
PHASE...THOUGH THAT IS NOT CERTAIN...AND THAT WOULD RESULT IN
GREATEST CHANCE OF SEEING HIGHER END SNOW EVENT.
NO MATTER HOW IT SHAKES OUT...THERE ARE INDICATIONS VERY CHILLY
AIRMASS...EVEN COLDER THAN ONE CURRENTLY AFFECTING THE REGION...WILL
SETTLE OVER UPR GREAT LAKES BY EARLY NEXT WEEK. BEYOND END OF
EXTENDED THERE ARE SIGNALS THAT RIDGE OVER EAST PACIFIC BREAKS DOWN
AND MORE MILD AIR RETURNS TO MUCH OF THE CONUS. PATTERN SHIFT THE
CFSV2 HAS BEEN SHOWING FOR A WHILE NOW. THUS...OVERALL IT DOES NOT
APPEAR THAT THE UPCOMING COLD WILL BE THAT LONG LASTING.
INTIALLY THE MAIN ISSUE WILL BE THE ONGOING WEST FLOW LAKE EFFECT
AND BLOWING SNOW WITH POOR VSBY OVER THE KEWEENAW. DECENT AGREEMENT
THAT SHORTWAVE DROPPING WNW-ESE OVER LK SUPERIOR AND UPR MICHIGAN
WEDNESDAY EVENING WITH LEADING SFC TROUGH AND ENHANCED CONVERGENCE
AND ADDITIONAL MOISTURE WILL RESULT IN A A BRIEF PERIOD OF MODERATE
TO HEAVY LES. WIND CORE MAX AT 950-925MB OVER 40 KTS WILL BE EASING
BY WEDNESDAY EVENING...BUT MIXED LAYER WINDS UP TO 40 KTS WILL STILL
RESULT IN STRONG/GUSTY WINDS OVER 30 MPH AND BLSN/POOR VSBY.
SOUNDINGS SHOW MARGINAL MOISTURE AND INSTABILITY FOR SIGNIFICANT LES
THOUGH AFTER THE TROUGH PASSAGE WITH INVERSIONS PEAKING AT 5-7 KFT
AGL WEDNESDAY EVENING AND LAKE INDUCED EQL NOT MUCH HIGHER THAN
THAT. MAJORITY OF THE MOIST LAYER IS WITHIN THE DGZ BUT STRONG WINDS
WILL LIKELY CUT DOWN SLR/S. POOR VSBY WILL BE THE BIGGER STORY
COMPARED TO SNOW AMOUNTS. AFTER COORDINATING WITH SHORT TERM
FORECASTER... DECIDED TO GO WITH LAKE EFFECT SNOW ADVISORY FOR SNOW
AND BLOWING SNOW WEDNESDAY AFTN THROUGH EARLY AFTERNOON ON NEW YEARS
DAY. WILL MENTION OCCASIONAL WHITEOUT CONDITIONS IN THE WSW
STATEMENT.
LAKE EFFECT AND BLOWING SNOW BECOME FACTOR LATE WEDNESDAY NIGHT INTO
THURSDAY FOR AREAS FAVORED BY WNW WINDS...ONTONAGON COUNTY OVER THE
WEST AND IN THE SNOW BELTS OF EASTERN HALF OF UPR MICHIGAN. LOOKING
AT ONLY A PURE LES SETUP AS SOUNDINGS SHOW SHARP DRYING ABOVE 8KFT.
TEMPS AT TOP OF INVERSION BLO -20C LEAD TO MARGINAL INSTABILITY GIVEN
WATER TEMPS 2-3C. MOST OF LAKE CONVECTIVE LAYER WILL BE IN THE DGZ
AND WINDS WILL BE DIMINISHING...SO FLUFF FACTOR WILL PLAY MORE OF A
ROLE. OVERALL...ADVY SNOW AMOUNTS SEEM POSSIBLE INTO NEW YEARS DAY
FOR THE WNW FLOW AREAS.
LAKE EFFECT LINGERS FOR WNW FLOW AREAS INTO FRIDAY...BUT WILL
CONTINUE TO DIMINISH AS HIGH PRESSURE RIDGE SLIDES ACROSS WESTERN
GREAT LAKES. COLD WILL SLOWLY EASE...THOUGH TEMPS WELL BLO ZERO
EXPECTED THURSDAY NIGHT OVER INTERIOR CNTRL UPR MICHIGAN. INCREASE
OF MID CLOUDS MAY RESULT IN LESS TEMP DROP OVER WEST CWA.
MAIN QUESTION THIS WEEKEND IS HOW MUCH PHASING OCCURS BTWN
APPROACHING NORTHERN STREAM SHORTWAVE TROUGH AND THE UPPER LOW
OPENING UP AS IT LIFTS INTO THE CNTRL PLAINS FM THE SOUTHWEST CONUS.
SINCE MAJORITY OF JET ENERGY REMAINS AHEAD OF THE SOUTHERN STREAM
TROUGH...WOULD EXPECT IT TO STAY FAIRLY PROGRESSIVE AND HAVE LESS
CHANCE OF PHASING WITH NORTHERN STREAM SYSTEM. EVEN SO...THE
NORTHERN STREAM SHORTWAVE ALONG WITH INCREASING NNE-NNW FLOW WITH
H85 TEMPS BLO -12C SATURDAY NIGHT INTO SUNDAY MAY LEAD TO SEVERAL
INCHES OF SNOW. BEST SHOT OF SYNOPTIC SNOW WOULD BE OVER THE SOUTH
AND EAST CWA WHILE THE GREATEST CHANCE FOR LAKE ENHANCEMENT WOULD BE
OVER THE WEST AND NORTH CENTRAL CWA. TIGHT PRESSURE GRADIENT RESULTS
IN GUSTY WINDS AND BLOWING SNOW AS WELL. MODEL TRENDS FOR THIS
SYSTEM ARE VARIABLE WITH EARLIER RUNS A FEW DAYS AGO SHOWING A
WRAPPED UP SYSTEM AND RECENT RUNS BACKING AWAY FM THAT. LATEST RUNS
SEEM TO BE TRYING TO COME BACK TO AT LEAST A FARTHER WEST TRACK TO
THE SOUTHERN STREAM SYSTEM IF NOT A MORE PHASED SYSTEM. SYSTEM BEARS
WATCHING AS IT COULD RESULT IN SOME HEADLINES.
BEHIND THE SYSTEM...LOOKS VERY COLD WITH H85 TEMPS DOWN TO -28C BY
NEXT MONDAY. INCREASED POPS FOR LAKE EFFECT IN WNW-W FLOW AREAS.
MAJORITY OF LAKE CONVECTIVE LAYER IS AT TEMPS BLO -20C...SO SLR/S
WILL BE LOW AND MAIN PROBLEM COULD BE POOR VSBY. COULD ALSO HAVE
WIND CHILL ISSUES FOR THE FIRST DAY BACK TO SCHOOL AFTER WINTER
VACATION.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1156 PM EST TUE DEC 30 2014
LAKE EFFECT SNOW WILL FAVOR PERSISTENT MVFR CIGS AND IFR/LIFR VSBY
AT CMX THROUGH THE PERIOD. GUSTY WINDS INTO WED MORNING WILL ALSO
REDUCE VSBY WITH BLSN. AT SAW AND IWD...VFR CONDITIONS WILL CONTINUE
THROUGH THE PERIOD. WILL GET GUSTY AT ALL SITES LATE TONIGHT THROUGH
WED.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 427 PM EST TUE DEC 30 2014
WEST TO SOUTHWEST GALES 40-45 KTS ARE EXPECTED OVER MOST OF LK
SUPERIOR BEGINNING LATER TONIGHT WILL SHIFT TO WEST-NORTHWEST GALES
TO 35 KTS LATE WEDNESDAY NIGHT INTO THURSDAY MORNING. IN ADDITION TO
THE GALES... HEAVY FREEZING SPRAY WILL AFFECT MOST OF THE LAKE INTO
THURSDAY. WINDS DIMINISH TO LESS THAN 25 KTS BY FRIDAY...BUT THE
LULL WILL BE BRIEF AS NORTHERLY WINDS INCREASE TO GALES TO 40 KTS
SATURDAY NIGHT INTO SUNDAY. MORE HEAVY FREEZING SPRAY WILL OCCUR AT
THIS TIME AS WELL.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WIND CHILL ADVISORY UNTIL 10 AM EST /9 AM CST/ WEDNESDAY FOR
MIZ002-004-005-009>012-084.
LAKE EFFECT SNOW ADVISORY FROM 1 PM WEDNESDAY TO 1 PM EST
THURSDAY FOR MIZ001-003.
LAKESHORE FLOOD ADVISORY FROM 6 AM WEDNESDAY TO MIDNIGHT EST
WEDNESDAY NIGHT FOR MIZ001-003.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 1 PM EST /NOON CST/ THURSDAY
FOR LSZ240>245-248>251-263>267.
GALE WARNING UNTIL 1 PM EST THURSDAY FOR LSZ244-245-264>267.
GALE WARNING FROM 7 PM WEDNESDAY TO 1 PM EST THURSDAY FOR
LSZ249>251.
GALE WARNING FROM 10 AM WEDNESDAY TO 1 PM EST THURSDAY FOR
LSZ246>248.
HEAVY FREEZING SPRAY WARNING UNTIL 1 PM EST THURSDAY FOR LSZ246-
247.
GALE WARNING UNTIL 7 AM EST /6 AM CST/ THURSDAY FOR LSZ162-
241>243-263.
HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST /6 AM CST/ THURSDAY
FOR LSZ162.
LAKE MICHIGAN...
HEAVY FREEZING SPRAY WARNING FROM 10 AM WEDNESDAY TO 1 PM EST
THURSDAY FOR LMZ221-248-250.
&&
$$
SHORT TERM...JLB
LONG TERM...JLA
AVIATION...07
MARINE...JLA
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1242 AM EST WED DEC 31 2014
.SYNOPSIS...
A WESTERLY FLOW OF COLD AIR ACROSS LAKE ONTARIO WILL DEVELOP LAKE
EFFECT SNOW TONIGHT WHICH WILL IMPACT NORTHERN ONEIDA COUNTY. MUCH
OF THE REST OF THE AREA WILL REMAIN DRY WITH ONLY SCATTERED SNOW
SHOWERS AND FLURRIES FROM TIME TO TIME.
&&
.NEAR TERM /THROUGH TODAY/...
820 PM UPDATE...
LAKE EFFECT SNOW BAND IS SHOWING ITS FIRST SIGNS OF ORGANIZATION
OVER NORTHEASTERN LAKE ONTARIO. MADE SLIGHT CHANGES TO THE GRIDS
AND TO THE WSW TEXT TO BRING THE STEADY SNOW INTO NORTHWESTERN
ONEIDA COUNTY SOMETIME BETWEEN 11 PM AND 2 AM. NAM AND RAP RADAR
OUTPUT SUGGEST THIS IS A LIKELY TIME WINDOW.
THE BAND WILL FLUCTUATE QUITE A BIT OVERNIGHT, SO NOT CONFIDENT
THAT ACCUMULATIONS WILL BE SIGNIFICANT BY MORNING. THE BAND SHOWS
BETTER ALIGNMENT AND A STEADIER STATE AFTER SUNRISE.
4 PM UPDATE...
AFTER A FINAL BURST...NW FLOW LE EVENT OVER THE CNTRL ZONES IS
FINALLY WINDING DOWN. ALREADY EVIDENCE OF BACKING FLOW OVER WRN NY
WHICH WILL END THE CNTRL NY SNOW...AND BEGIN TO DVLP THE SINGLE
BAND LE EVENT XPCTD LTR TNGT AND WED. MODELS AND FCST OFFICES IN
GNRL AGREEMENT ON THE IDEA THAT A SINGLE BAND WILL DVLP AFT 00Z.
DFCLTY IS IN THE PLACEMENT OF THE BAND WITH A MEAN FLOW ARND
260-270 WHICH SHD JUST CLIP THE POINTS IN NRN ONEIDA COUNTY.
ALSO...MODEL FCSTD REFLECTIVITY AND QPF HAS A LIMITED INLAND
EXTENT OF THE HEAVIER BANDS. FOR THAT REASON...XPCT THE HEAVIEST
SNOW IN THE FAR NE CORNER OF NYZ009...WITH LESSER AMTS BUT STILL
ARND WARNING CRITERIA OVER THE NW. TIMING BRINGS THE BAND INTO THE
WARNING AREA BETWEEN 03Z AND 06Z. BAND MAY BRIEFLY LFT NORTH ARND
DAYBRK AS A WV ZIPS BY BEFORE SETTLING BACK IN THE NRN PARTS OF
ONEIDA FOR MUCH OF THE REST OF THE DAY. LOOKS LIKE THE BAND LFTS
OUT FOR GOOD AFT 21Z.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY/...
SOUTHWEST FLOW CONTS WED NGT INTO THU KEEPING LAKE ERIE AND
ONTARIO BAND OUT OF THE AREA. SOME LIFT OVER THE TERRAIN...ESP THE
WRN CATS...COULD GENERATE SOME LGTR FLURRIES AT TIMES...AND THE
FINGER LAKES COULD SEE A BOT OF LGT SNOW SHWR ACTIVITY AT THE EDGE
OF THE LE.
SHRT WV THU NGT AND EARLY FRI WILL BRING A MORE NWLY FLOW AND A
RE-ENFORCING SHOT OF COLD AIR. THIS SHD HELP BRING MORE WIDESPREAD
SNOW SHWRS AND FLURRIES TO THE FCST AREA LATE THU NGT AND ON FRI.
WITH THE BROAD TROFF OVER THE AREA AND ARCTIC SOURCE REGION FOR
OUR AIR...TEMPS SHD AVG BLO NRML THRU THE SHRT TERM PD.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
230 PM UPDATE...
HIPRES WL START OFF THE LONG TERM PORTION OF THE FCST. 1040MB SFC
HIGH WL RESULT IN COLD-AIR DAMMING BFR NEXT STORM SYSTEM MVS IN FOR
LATE IN THE WEEKEND. H5 S/WV EJECTS OUT OF THE SRN PLAINS ON
SATURDAY AND LOOKS TO PHASE WITH WV DROPPING DOWN THRU THE UPR
MIDWEST. MED RANGE MODELS COMING INTO BETTER AGREEMENT WITH SFC
CYCLOGENESIS OCCURRING IN VICINITY OF GREAT LKS 06Z SUNDAY.
MOISTURE WL ENTER CWA AFT 18Z SAT IN THE FORM OF RAIN/SNOW, MAINLY
SNOW ACRS THE COLD-AIR DAMMED ERN ZONES. WARM AIR WRAPS IN RAPIDLY
LATE SAT NGT WITH A WINTRY MESS EXPECTED THRU 12Z SUN BFR DRY SLOT
WORKS IN.
AFT SYSTEM DEPARTS JUST EXPECTING WRAP-ARND SHOWERS ON SUNDAY. WITH
COLD-AIR FILTERING IN BHND EXPECT A VRY GRADUAL CHANGEOVER TO SNOW
SHOWERS THRU THE AFTN. BY 00Z MONDAY JUST EXPECT LK EFFECT SNOW
SHOWERS THROUGH THE END OF THE LONG TERM.
TEMPS WL BE TRICKY THRU THE PD. TEMPS WL BE NEAR TO SLIGHTLY ABV
NORMAL FOR THE WEEKEND. CANNOT RULE OUT A NON-DIURNAL TEMP TREND FOR
SAT NGT AS TEMPS WARM WITH SYSTEM PASSING TO THE WEST. BHND LOW
TEMPS DROP DOWN TO BLO NORMAL VALUES AGAIN INTO EARLY NEXT WEEK.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
LAKE EFFECT CLOUDS AND SNOW SHOWERS WILL RESULT IN MAINLY LOW END VFR TO
MVFR CONDITIONS OVERNIGHT INTO WEDNESDAY FOR KRME/KSYR/KITH. AS A
BAND CONTINUES TO GET ORGANIZED OVERNIGHT EAST OF LAKE ONTARIO WE
EXPECT THE BRUNT OF THIS BAND TO STAY MAINLY NORTH OF KRME/KSYR
HOWEVER KRME WILL LIKELY BE IN AND OUT OF SNOW SHOWERS RESULTING
IN MVFR CIGS AND AT TIMES MVFR VISBYS. A PERIOD OF IFR VISBYS IS
LIKELY WEDNESDAY MORNING FOR KRME AS THE BAND BRIEFLY SHIFTS
SOUTH. KSYR SHOULD STAY DRY OVERNIGHT BUT WILL LIKELY SEE SOME
SNOW SHOWERS AT TIMES WEDNESDAY MORNING RESULTING IN MVFR
CIGS/VISBYS. EXPECT VARIABLE CONDITIONS FOR KITH AS THEY REMAIN IN
AND OUT OF FLURRIES OFF LAKE ERIE OVERNIGHT INTO WEDNESDAY MORNING
RESULTING IN MVFR CONDITIONS AT TIMES AND EVEN BRIEF IFR CIGS.
KRME/KSYR/KITH ARE EXPECTED TO ALL BE VFR BY LATE DAY WEDNESDAY AS
THE LAKE EFFECT SHIFTS NORTH WITH THE REMAINING THREE SITES
(KBGM/KELM/KAVP) EXPECTED TO STAY VFR THROUGH THE TAF PERIOD.
OUTLOOK...
WED NIGHT THRU FRI...RESTRICTIONS POSSIBLE AT TIMES FOR KRME/KSYR
DUE TO MEANDERING LAKE EFFECT -SHSN. OTHERWISE VFR IS EXPECTED.
SAT/SAT NGT...CHANCE FOR MIXED PRECIP AND ASSOCIATED RESTRICTIONS.
SUN...MVFR RESTRICTIONS POSSIBLE IN LIGHT SNOW SHOWERS BEHIND
DEPARTING SYSTEM.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...LAKE EFFECT SNOW WARNING UNTIL 7 PM EST THIS EVENING FOR
NYZ009.
&&
$$
SYNOPSIS...DGM/DJP
NEAR TERM...DGM
SHORT TERM...DGM
LONG TERM...PVF
AVIATION...PCF/RRM
AREA FORECAST DISCUSSION
NWS BISMARCK ND
137 AM CST WED DEC 31 2014
.UPDATE...
ISSUED AT 137 AM CST WED DEC 31 2014
NORTHWEST FLOW ALOFT THIS MORNING WITH DEEP LOW PRESSURE TO OUR
NORTHEAST OVER THE HUDSON BAY. TIGHT PRESSURE GRADIENT AROUND THE
LOW EXTENDS ACROSS THE NORTHERN PLAINS...AND CREATES A RATHER
ROBUST SOUTHWEST WIND. WEAK WAA COUPLED WITH THIS STRONG MIXING
WIND RESULTS IN TEMPERATURES STEADY OR RISING ACROSS WEST AND
CENTRAL NORTH DAKOTA.
WE ARE BARELY REACHING WIND CHILL CRITERIA SOME LOCATIONS AND NOT
AT ALL MOST PLACES. WILL KEEP HEADLINES AS IS FOR THIS UPDATE BUT
WILL BE CANCELING ALL HEADLINES WITH THE NEXT FORECAST UPDATE 3-4
AM CST.
LARGE AREA OF LOW STRATUS OVER SOUTH CENTRAL CANADA IS SURGING
SOUTHWARD TOWARDS THE NORTHERN PLAINS. TIME OF ARRIVAL PUTS THE
LEADING EDGE OF THE CLOUDS ACROSS THE INTERNATIONAL BORDER BY
AROUND 9-10Z AND ACROSS ALL OF WEST AND CENTRAL NORTH DAKOTA BY
18Z AT THE LATEST. THUS SIGNIFICANT CHANGES WERE MADE TO SKY GRIDS
FOR THIS UPDATE. LATEST RAP AND GFS HAVE THE BEST HANDLE ON THE
CLOUDS. STRATUS LOOKS TO LINGER OVER MY NORTH CENTRAL AND EAST
THROUGH MUCH OF WEDNESDAY....WITH MODELS INDICATING SOME EROSION
OVER THE WEST/CENTRAL WED AFTERNOON. OPTED TO THROW IN ISOLATED
FLURRIES AS WELL THIS MORNING WITH NUMEROUS OBSERVING SITES IN
SOUTH CENTRAL CANADA REPORTED LIGHT SNOW BUT WITH VISIBILITIES
P6SM. HELD OFF ON AFTERNOON FLURRIES FOR NOW.
UPDATE ISSUED AT 931 PM CST TUE DEC 30 2014
WINDS ARE BEGINNING TO INCREASE OVER NORTHWESTERN NORTH DAKOTA IN
RESPONSE TO LOW PRESSURE ENTERING NORTHERN MANITOBA. EVEN THOUGH
THE WIND SPEEDS ARE INCREASING...SO ARE THE AMBIENT AIR TEMPERATURES
DUE TO VERTICAL MIXING.
WIND CHILLS ARE STILL EXPECTED TO DIP TO NEAR 30 BELOW ZERO OVER
WESTERN AND CENTRAL NORTH DAKOTA TONIGHT. HOWEVER...IT IS LIKELY
THAT NORTHWESTERN AND PARTS OF NORTH CENTRAL NORTH DAKOTA HAVE
ALREADY OBSERVED THEIR OVERNIGHT LOWS...WITH INCREASING AMBIENT
AIR TEMPERATURES FORECAST NORTH THROUGH THE REST OF THE NIGHT DUE
TO INCREASING WIND SPEED/VERTICAL MIXING.
ONLY MADE MINOR ADJUSTMENTS TO THE HOURLY TEMP/DEWPOINT/WIND GRIDS
BASED ON CURRENT OBS/TRENDS. THE CURRENT WIND CHILL ADVISORY LOOKS
TO BE IN GOOD SHAPE AS WELL. THE UPDATED PRODUCTS HAVE BEEN SENT.
UPDATE ISSUED AT 533 PM CST TUE DEC 30 2014
NO MAJOR UPDATES WERE REQUIRED TO THE ONGOING FORECAST. THE
CURRENT WIND CHILL ADVISORY FOR TONIGHT IS IN GOOD SHAPE. ONLY
ADJUSTED THE HOURLY SENSIBLE WEATHER GRIDS BASED ON CURRENT
OBS/TRENDS. THE FRESHENED UP PRODUCTS HAVE BEEN SENT.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 312 PM CST TUE DEC 30 2014
SEVERAL AREAS OF CONCERN TONIGHT. TEMPERATURES ONLY WARMED TO
AROUND ZERO MOST AREAS TODAY AND EVENING TEMPERATURES LIKELY TO
FALL QUICKLY INITIALLY. STRENGTHENING MID LEVEL FLOW ALONG WITH
SURFACE PRESSURE GRADIENT ASSOCIATED WITH DEPARTING ARCTIC HIGH
WILL BRING INCREASING WESTERLY WINDS. THIS CAUSES WIND CHILL
ISSUES AGAIN TONIGHT WITH VALUES FALLING TO 25 TO 30 BELOW MOST
AREAS. ALTHOUGH NOT AS WIDESPREAD AND COLD AS LAST NIGHT...IN CO-
ORDINATION WITH SURROUNDING OFFICES WILL ISSUE ANOTHER WIND CHILL
ADVISORY TONIGHT. WARMING AFTER MIDNIGHT WILL BE COUNTERBALANCED AT
FIRST WITH INCREASING WINDS. EVEN THOUGH 850MB WINDS ARE 50KTS
ACROSS THE REGION TONIGHT DO NOT THINK THIS WILL NAVIGATE TO THE
SURFACE. STRONG WARM ADVECTION WILL LIMIT THE POTENTIAL FOR
MOMENTUM TRANSFER. HOWEVER THINK WITH 20 TO 30 MPH WIND GUSTS
NORTH CENTRAL AND SOUTHWEST THERE WILL BE SOME PATCHY BLOWING
SNOW TONIGHT. WEDNESDAY BREEZY AND NOT AS COLD.
.LONG TERM...(NEW YEARS EVE WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 312 PM CST TUE DEC 30 2014
NEW YEARS EVE: EXPECTING WESTERLY WINDS AT 10 TO 15 MPH TO PERSIST
THROUGH THE NIGHT. NEUTRAL TEMPERATURE ADVECTION WITH THE STATE
BETWEEN SYSTEMS - THUS TEMPERATURES SHOULD NOT DROP MUCH FROM THE
DAYTIME HIGHS ON WEDNESDAY...WITH EXPECTED LOW TEMPERATURES FROM
NEAR 10 ABOVE TO 15 ABOVE. LOOK FOR INCREASING CLOUDS FROM NORTH TO
SOUTH WITH THE APPROACH OF AN UPPER LEVEL SHORTWAVE MOVING SOUTHEAST
TOWARDS NORTH DAKOTA FROM SASKATCHEWAN. AFTER MIDNIGHT THERE IS A
CHANCE OF LIGHT SNOW...MAINLY ACROSS THE BOTTINEAU/TURTLE MOUNTAINS
AREA TO THE NORTHERN JAMES VALLEY.
NEW YEARS DAY: THE UPPER LEVEL SHORTWAVE CONTINUES MOVING SOUTHEAST
AS A WEAK COLD FRONT DROPS SOUTH ACROSS THE STATE. A SLIGHT CHANCE
OF LIGHT SNOW WITH VERY LIGHT ACCUMULATIONS EXPECTED. HIGHS SHOULD
RANGE FROM THE TEENS NORTH CENTRAL THROUGH JAMESTOWN...TO THE UPPER
20S IN THE SOUTHWEST.
NORTHWESTERLY FLOW REMAINS OVER THE REGION THROUGH REST OF THE
PERIOD WITH A VARIETY OF DISTURBANCES SLIDING THROUGH. THE
NEXT...AND MORE SIGNIFICANT...WAVE APPROACHES THE AREA ON FRIDAY
INTO SATURDAY. MODELS HAVE BEEN HAVING SOME TROUBLE ON THE EXACT
PLACEMENT OF SOME KEY FEATURES...BUT THE MAIN POINT IS THAT THERE IS
A RATHER GOOD CHANCE FOR SNOWFALL FRIDAY AFTERNOON THROUGH SATURDAY.
THE LATEST ESTIMATES ARE FOR 1 TO 3 INCH AMOUNTS THROUGH THIS
PERIOD. FINALLY...ANOTHER SHORT WAVE IS EXPECTED TO PUSH THROUGH THE
NORTHERN PLAINS ON MONDAY. AGAIN...POSITION OF SYSTEM IS STILL IN
QUESTION BUT MEASURABLE SNOWFALL IS POSSIBLE.
TEMPERATURES WILL BE NEAR TO ABOVE AVERAGE FRIDAY...BUT LOOK FOR
BELOW AVERAGE TEMPERATURES THIS WEEKEND AND INTO EARLY NEXT WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY EVENING)
ISSUED AT 137 AM CST WED DEC 31 2014
MVFR STRATUS WILL SURGE SOUTHWARD 09-15Z ACROSS NORTH DAKOTA.
KISN-KMOT WILL SEE INCREASING LOW CLOUDS 10-12Z...AND KBIS-KJMS-
KDIK 14-16Z. STRATUS ERODES OVER WESTERN AND SOUTH CENTRAL
TERMINALS LATER WED MORNING INTO THE AFTERNOON...BUT COULD LINGER
NORTH CENTRAL AND EAST INTO WED EVENING.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY UNTIL 6 AM CST /5 AM MST/ EARLY THIS MORNING
FOR NDZ001>005-009>013-017>023-025-031>037-040>048-050-051.
&&
$$
UPDATE...NH
SHORT TERM...WAA
LONG TERM...JV
AVIATION...NH
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
342 AM PST WED DEC 31 2014
...A COLD AND WINDY END TO 2014...
.SYNOPSIS...GUSTY NORTH TO NORTHEAST WINDS WILL CONTINUE THROUGH
MID MORNING BEFORE DIMINISHING TODAY. THE COLD AIRMASS IN PLACE
AND CLEAR SKIES WILL RESULT IN THE COLDEST TEMPERATURES OF THE
SEASON TONIGHT. TEMPERATURES GRADUALLY WARM LATE IN THE WEEK INTO
THE WEEKEND.
&&
.DISCUSSION...AS OF 3:30 AM PST WEDNESDAY...A DEEP UPPER LOW THAT
MOVED THROUGH THE AREA IS NOW CENTERED OVER SOUTHERN CALIFORNIA.
THE SURFACE LOW ALSO OVER SOUTHERN CALIFORNIA COMBINED WITH STRONG
HIGH PRESSURE OVER THE GREAT BASIN HAS RESULTED IN ROBUST PRESSURE
GRADIENTS DRIVING STRONG WINDS SINCE LATE MORNING YESTERDAY.
NUMEROUS DOWNED TREES WERE NOTED...SEE LOCAL STORM REPORT
SUMMARY...AND CAUSED THOUSANDS TO LOSE ELECTRICAL POWER.
THE WINDS HAVE SUBSIDED SOMEWHAT OVERNIGHT...PARTICULARLY OVER
LOWER ELEVATIONS AS VERTICAL MIXING HAS DECREASED...THOUGH WINDS
REMAIN GUSTY. SFO IS STILL GUSTING TO 31 MPH WHILE MT DIABLO
REPORTS A PEAK WIND OF 51 MPH IN THE LAST HOUR. THESE STRONGER
WINDS WILL CONTINUE TO DECREASE THROUGH THE MORNING AS THE LOW
CENTER CONTINUES TO MOVE SOUTH. WINDS HAVE KEPT THE ATMOSPHERE
MIXED OVERNIGHT PREVENTING VERY COLD TEMPERATURES FROM DEVELOPING
THOUGH THE BRISK WINDS ARE MAKING IT FEEL RATHER COLD.
AS WINDS DIMINISH TODAY...TEMPERATURES ARE FORECAST TO BE
ESPECIALLY COLD TONIGHT. THE COLD DRY AIRMASS COMBINED WITH CLEAR
SKIES PROMOTING RADIATIONAL COOLING WILL ALLOW TEMPERATURES TO
DROP BELOW FREEZING IN MANY INLAND AREAS AND INTO THE LOW TO MID
30S NEAR SF BAY.
THE AIRMASS GRADUALLY WARMS INTO THE END OF THE WEEK AS RIDGING
STARTS TO NUDGE INTO THE AREA FROM THE WEST. TEMPS WILL GRADUALLY
INCREASE THOUGH THE COLD DRY AIR WILL LIKELY STICK AROUND FOR
ANOTHER NIGHT. AS THE RIDGE CONTINUES TO BUILD INTO THE WEEKEND
TEMPS WILL RISE TO NEAR NORMAL THOUGH THE LONG CLEAR WINTER NIGHTS
WILL KEEP OVERNIGHT LOWS CHILLY.
DRY WEATHER WILL CONTINUE THROUGH THE FORECAST PERIOD. THE GLOBAL
MODELS POINT TO A SHORTWAVE IMPACTING THE AREA THE MIDDLE OF NEXT
WEEK. THE AFTERNOON RUN OF THE GFS HAS INCREASED THE INTENSITY OF
THIS STORM THOUGH IT APPEARS TO LACK A CONNECTION TO SUBTROPICAL
MOISTURE WITH A SIGNIFICANT BLOCKING PATTERN FURTHER WEST IN THE
PACIFIC.
&&
.AVIATION...AS OF 10 PM PST TUESDAY...AN ENERGETIC WINDSTORM WILL
CONTINUE TO BRING GUSTY NORTH WINDS WHILE DESCENDING INTO SOUTHERN
CALIFORNIA LATE THIS EVENING. AIRPORTS ACROSS THE REGION HAVE
REPORTED SIGNIFICANT DECLINES IN WIND SPEEDS WITH THE NOTABLE
EXCEPTION OF SFO... WHICH CONTINUES TO GUST TO AROUND 40KTS.
MODELS HAVE STRUGGLED WITH WIND SPEEDS AND TIMING SO FAR...
HOWEVER THE HRRR HAS BEEN CONSISTENT IN WEAKENING NEAR SURFACE
WINDS BY 07Z SINCE THIS AFTERNOON. WINDS AND GUSTS WILL DIMINISH
THROUGH THE NIGHT.
VICINITY OF KSFO...VFR. NORTH WINDS WILL REMAIN GUSTY THROUGH THE
NIGHT AT KSFO. STRONGEST WINDS SHOULD DIMINISH AFTER 07Z.
KSFO BRIDGE APPROACH...SIMILAR TO KSFO.
MONTEREY BAY AREA TERMINALS...VFR.
&&
.MARINE...AS OF 03:02 AM PST WEDNESDAY...MODERATE NORTHERLY WINDS
WILL PERSIST OVER PORTIONS OF THE COASTAL WATERS THIS
MORNING...BUT ARE EXPECTED TO DIMINISH THROUGH OUT THE DAY AS THE
PARENT STORM SYSTEM MOVES FURTHER INLAND. EXPECT FRESH SWELL WITH
CHAOTIC SEAS ALONG THE COAST THIS MORNING. SEAS WILL IMPROVE THIS
EVENING AS THE WINDS DIMINISH. GENTLE SEAS AND LIGHT WINDS ARE
THEN EXPECTED THROUGH THE WEEKEND.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.TDAY...WIND ADVISORY...ENTIRE SF BAY AREA AND SANTA CRUZ COUNTY
SCA...MONTEREY BAY UNTIL 9 AM
SCA...PT REYES TO PIGEON PT 0-10 NM UNTIL 9 AM
SCA...PIGEON PT TO PT PINOS 0-10 NM UNTIL 9 AM
SCA...SF BAY NORTH OF THE BAY BRIDGE UNTIL 1 PM
SCA...SF BAY SOUTH OF THE BAY BRIDGE UNTIL 1 PM
SCA...PT REYES TO PIGEON PT 10-60 NM UNTIL 1 PM
SCA...PIGEON PT TO PT PINOS 10-60 NM UNTIL 1 PM
SCA...PT PINOS TO PT PIEDRAS BLANCAS 10-60 NM UNTIL 1 PM
&&
$$
PUBLIC FORECAST: AC
AVIATION: DRP
MARINE: LARRY
VISIT US AT WEATHER.GOV/SANFRANCISCO
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AREA FORECAST DISCUSSION
NWS MELBOURNE FL
953 AM EST WED DEC 31 2014
.DISCUSSION...
...OVERCAST AND COOL MOST PLACES...
...POOR BOATING CONDITIONS TODAY...
TODAY...RADAR SHOWING A BAND OF SHOWERS OFFSHORE ST LUCIE AND MARTIN
COUNTIES WITH INDICATIONS OF WEAK LOW LEVEL SWIRL. THIS REPRESENTS
A FLORIDA FRONTAL SIGNATURE. THE BOUNDARY THEN SNAKES WEST/SOUTHWEST
ACROSS THE SOUTHERN PENINSULA. THE MAIN QUESTION REVOLVES AROUND
POPS AND WHETHER SOME OF THE DOWNPOURS OFFSHORE WILL IMPACT THE
COAST...PARTICULARLY THE TREASURE COAST.
THE GFS KEEPS THE MAIN AREA OF MODERATE PRECIP AMOUNTS OFFSHORE.
EVEN THE NAM...WHICH SHOWS THE WEAK LOW LEVEL SWIRL...DOES NOT BRING
ANY MODERATE AMOUNTS INTO THE COAST. THE HRRR AND LOCAL WRF ARE ALSO
NOT BULLISH WITH PRECIP ALONG THE SOUTH COAST.
THE REST OF THE AREA WILL HAVE EXTENSIVE LOW CLOUDINESS AS EVIDENCED
BY SATELLITE AND SOUNDINGS WHICH SHOW MOISTURE OVERRUNNING THE
SHALLOW COOL AIR. OVERALL ISENTROPIC LIFT HAS BEEN DIMINISHING SO
THE MAIN CHANCE FOR LIGHT PRECIP WILL BE ALONG THE COAST WHERE LOW
LEVEL ONSHORE FLOW IS DEVELOPING. FLOW OFF THE COOL SHELF WATERS
AND CLOUD COVER WILL KEEP MAX TEMPS DOWN ESPECIALLY IN THE NORTH.
MAY HAVE TO TWEAK READINGS DOWN A FEW DEGREES EVERYWHERE.
PRELIMINARY POP GRID UPDATE SHOWS POPS TRIMMED BACK INLAND AND NORTH
WITH LIGHT PRECIP AMOUNTS...AND HIGHEST POPS/QPF ALONG THE TREASURE
COAST.
&&
.AVIATION...PREVAILING MVFR CEILINGS WITH AREAS OF IFR ACROSS THE
NORTH TERMINALS FOR MUCH OF THE PERIOD. FEW PATCHES OF LIGHT
RAIN/MIST THERE TOO. SOME OF THE SHOWER ACTIVITY PUSHING INTO THE
COAST KMLB TO KSUA COULD ALSO RESULT IN IFR CONDITIONS. ONLY SMALL
UPDATES EXPECTED TO THE CURRENT SET OF TAFS.
&&
.MARINE...
CURRENTLY-NEW YEARS DAY...NORTH/NORTHEAST WIND SURGE WORKING
DOWN THE COAST BEHIND FRONTAL BOUNDARY WILL PRODUCE MARGINALLY
HAZARDOUS CONDITIONS FOR SMALL CRAFT FROM ABOUT CAPE CANAVERAL
NORTHWARD.
CONTINUED VEERING OF THE WINDS SHOULD CAUSE THE FRONTAL BOUNDARY TO
REMAIN QUASI STATIONARY NEAR THE SOUTHERN WATERS. THIS WILL LIKELY
RESULT IN LIGHTER AND MORE VARIABLE WINDS THERE...BUT WEATHER WILL
BE POOR DUE TO A HIGHER COVERAGE OF SHOWERS.
THE NAM INDICATES NORTHEAST/EAST WINDS REMAINING ELEVATED LONGER IN
THE NORTH WITH A WEAK LOW SPINNING UP OFF OUR COAST. WILL NOT QUITE
GO WITH THAT SOLUTION YET...BUT FAVOR THE 15-20 KNOT WINDS HOLDING
ON LONGER THAN THE GFS INDICATES.
THEREFORE WILL FORECAST SMALL CRAFT EXERCISE CAUTION IN THE
NORTHERN WATERS INTO TONIGHT. EARLY NEW YEARS DAY BOATING
CONDITIONS MAY ALSO BE POOR IN THE NORTH...SO SMALL CRAFT OPERATORS
WILL WANT TO KEEP THAT IN MIND WHEN PLANNING THEIR ACTIVITIES.
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
FORECASTS...LASCODY
IMPACT WX...WIMMER
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
613 AM EST WED DEC 31 2014
LATEST UPDATE...
UPDATE/AVIATION
.SYNOPSIS...
ISSUED AT 326 AM EST WED DEC 31 2014
LIGHT LAKE EFFECT SNOW SHOWERS WILL CONTINUE THIS MORNING AND THEN
DIMINISH LATE THIS AFTERNOON AND EVENING AS THE CORE OF THE COLD AIR
ALOFT MOVES EAST. BREEZY CONDITIONS WILL DEVELOP BY THIS AFTERNOON
ESPECIALLY NEAR THE LAKE NORTH OF US-10. APPARENT TEMPERATURES WILL
FALL TO AROUND 0 TONIGHT. ANOTHER COLD FRONT WILL DROP SOUTH
THURSDAY NIGHT PROVIDING ANOTHER OPPORTUNITY FOR LIGHT SNOW SHOWERS.
&&
.UPDATE...
ISSUED AT 611 AM EST WED DEC 31 2014
I DISPLACED THE HIGHEST POP AND GREATEST SNOW ACCUMULATIONS INLAND
TO NEAR US-131 INSTEAD OF NEAR THE LAKE SHORE. CURRENTLY (6 AM)
THE LOWEST REPORTED VISIBILITIES ARE LOCATIONS NEAR US-131
(RQB...FFX...GRR TO LAN ) AND NOT BY THE LAKE SHORE. ALL STATIONS
NEAR THE LAKE SHORE HAVE HAD VISIBILITIES GREATER THAN 6 MILES SINCE
I CAME TO WORK AROUND MIDNIGHT. THE HRRR AND NAM ALSO SHOW THE
LOCATION OF THE HIGHEST ACCUMULATION NEAR AND NORTH OF I-96...BY
US-131 INTO THIS AFTERNOON. THE REASON FOR THIS IS THE WINDS IN
THE CLOUD LAYER INCREASING TO 40 KNOT. THOSE STRONG OF WIND ALWAYS
BLOW THE HEAVIEST SNOW SHOWERS INLAND. THERE SHOULD BE DECREASE IN
THE SNOW SHOWER ACTIVITY THIS AFTERNOON AS MID LEVEL TEMPERATURES
START TO RISE AND SHORTWAVE CAUSING THE CURRENT BUST OF ACTIVITY
MOVES EAST OF THE AREA.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 326 AM EST WED DEC 31 2014
FORECAST CONCERNS DEAL WITH LAKE EFFECT SNOW SHOWERS TODAY AND WINDS
THIS AFTERNOON.
RADAR SHOWS SHSN CONTINUING ACROSS THE WESTERN CWA AS THE CORE OF
THE COLD AIR MOVES THROUGH. H8 TEMPS NEAR -20C ARE PROVIDING GOOD
INSTABILITY OVER THE LAKE. EVEN THOUGH MOISTURE IS SHALLOW...WE/RE
SEEING SOME LIGHT SNOW. ACCUMS ARE ONLY A FEW TENTHS OF AN INCH
THOUGH DUE TO A LOW AND SHALLOW DGZ WITH LIMITED LIFT WITHIN THAT
ZONE. AS THE CORE OF THE COLD AIR MOVES EAST...THE SHSN WILL
DIMINISH LATE TODAY. WINDS WILL ALSO INCREASE AS THE NEXT COLD FRONT
DROPS SOUTH INTO THE NORTHERN GREAT LAKES. WIND PROFILES IN THE FAR
NW CWA SUGGEST WE COULD SEE WIND GUSTS IN EXCESS OF 45 KTS...SO WE
HAVE ISSUED A WIND ADVISORY FOR MASON COUNTY FROM THIS AFTERNOON
THROUGH TONIGHT.
A STRONG SHORT WAVE WILL ACCOMPANY THE COLD FRONT THURSDAY AND
THURSDAY NIGHT AS IT MOVES OVER NORTHERN LOWER MICHIGAN. SOME LIGHT
SNOW IS POSSIBLE WITH THE SYSTEM WITH BOUNDARY LAYER RH AROUND 90
PERCENT. OVERALL MOISTURE IS DEEPER WITH THIS SYSTEM BUT THE MAIN
AREA OF LIFT IS WELL BELOW THE DGZ WHICH IS PROGGED AOA 10K FT. THIS
WILL CUT DOWN ON ACCUMS QUITE A BIT. PLACED HIGHEST POPS OVER THE
NRN CWA.
.LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY)
ISSUED AT 326 AM EST WED DEC 31 2014
MY FORECAST CONFIDENCE FOR A SYSTEM MOVING THROUGH SOUTHERN LOWER
MICHIGAN SATURDAY INTO EARLY SUNDAY CONTINUES TO INCREASE. IT IS
LOOKING MORE AND MORE LIKE MOSTLY SNOW...WITH MIXED PRECIPITATION IN
THE I-69 AREA SATURDAY EVENING. BEHIND THAT MUCH COLDER AIR MOVES IN
THAT WILL REMAIN IN PLACE MOST OF NEXT WEEK. LAKE EFFECT SNOW WILL
BE ACTIVE THROUGH THE SUNDAY TO TUESDAY TIME FRAME.
THE SATURDAY STORM SYSTEM RESULTS FROM THE PHASING OF THREE SYSTEMS.
WHAT PHASES IS THE CLOSED UPPER LOW CURRENTLY OVER THE SOUTHWEST
UNITED STATES....AND A DIGGING ARCTIC SHORTWAVE AND A PACIFIC
SHORTWAVE. THE PHASING OF THESE THREE SYSTEMS HAPPENS ON SATURDAY AS
THE STORM APPROACHES OUR AREA. THERE IS STILL SOME QUESTION AS TO
THE TRACK AND HOW MUCH WARM AIR COMES WEST OF THE SYSTEM. HOWEVER...
UNLIKE THE SYSTEM ON CHRISTMAS...THIS SYSTEM HAS A LOT OF COLD AIR
TO WORK WITH SO THERE SHOULD BE MUCH LESS OF AN ISSUE WITH GETTING A
SIGNIFICANT AMOUNT OF THE STORMS PRECIPITATION IN OUR CWA TO BE SNOW
GIVEN THE TRACK IS THROUGH SOUTHEAST MICHIGAN. I STILL ALLOWED FOR
SLEET...FREEZING RAIN TO MIX IN OVER MOST AREAS NEAR AND EAST OF
GRAND RAPIDS SATURDAY AFTERNOON. THIS WILL HAVE TO BE ADJUSTED AS
THE STORM TRACK BECOMES MORE CERTAIN.
BEHIND THE SYSTEM WE TO HAVE THE ISSUE WITH SPLITTING POLAR VORTEX.
THAT WILL ASSURES A SIGNIFICANT PUSH OF MUCH COLDER AIR BEHIND THE
SYSTEM SATURDAY NIGHT. BOTH THE ECMWF AND GFS HAVE 850 TEMPS
FALLING TO NEAR -25C IN THE MONDAY-TUESDAY TIME FRAME. GIVEN THAT
AMOUNT OF COLD AIR AND A SERIES OF SHORTWAVES ON THE NORTHERN BRANCH
OF THE POLAR JET..LITTLE QUESTION IN MY MIND...LAKE EFFECT SNOW WILL
BE ON-GOING THROUGH THE MIDDLE OF NEXT WEEK.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 611 AM EST WED DEC 31 2014
FOR THE MOST PART MVFR CEILING PREVAIL AT MOST TAF SITES AT 11Z THIS
MORNING. SNOW SHOWERS HAVE BROUGHT IFR VISIBILITIES TO GRR....LAN
AND JXN OVER THE PAST FEW HOURS BUT NOT MKG...AZO OR BTL. I EXPECT
THE SNOW SHOWER ACTIVITY TO CONTINUE INTO LATE MORNING BEFORE
DECREASING SOME AS DRIER AIR MOVES IN. I WOULD ALSO EXPECT THE
I-96 TAF SITES... EXCEPT FOR MKG (TO CLOSE TO THE LAKE SHORE WITH
THE STRONG WINDS IN THE CLOUDS TODAY) WILL CONTINUE TO SEE
OCCASIONAL IFR VISIBILITIES IN SNOW SHOWERS INTO LATE MORNING OR
EARLY AFTERNOON. VFR CONDITIONS WITH STRONG WEST WINDS WILL
PREVAIL THIS AFTERNOON. ADDITIONAL LIGHT SNOW SHOWERS WILL
REDEVELOP AFTER 06Z AS ANOTHER SHORTWAVE MOVES INTO THE AREA.
&&
.MARINE...
ISSUED AT 326 AM EST WED DEC 31 2014
EXTENDED THE SCA THROUGH THIS MORNING AND ISSUED A GALE WARNING FROM
NOON THROUGH TONIGHT. WINDS WILL INCREASE TO 40 KTS BY THIS EVENING
AS DEEP MIXING DEVELOPS IN THE WAKE OF THE COLD FRONT.
&&
.HYDROLOGY...
ISSUED AT 326 AM EST WED DEC 31 2014
COLD TEMPS WILL CONTINUE TO AID IN ICE DEVELOPMENT ON AREA
WATERWAYS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WIND ADVISORY FROM NOON TODAY TO 6 AM EST THURSDAY FOR MIZ037.
LM...SMALL CRAFT ADVISORY UNTIL NOON EST TODAY FOR LMZ844>849.
GALE WARNING FROM NOON TODAY TO 6 AM EST THURSDAY FOR LMZ844>849.
&&
$$
UPDATE...WDM
SYNOPSIS...93
SHORT TERM...93
LONG TERM...WDM
AVIATION...WDM
HYDROLOGY...93
MARINE...93
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
920 AM CST WED DEC 31 2014
.UPDATE...
LET THE WIND CHILL ADVISORY EXPIRE AT 15Z AS FORECAST. READINGS
ARE PRETTY MUCH OUT OF CRITERIA NOW AND WIND CHILLS WILL SLOWLY
IMPROVE THROUGH THE REMAINDER OF THE MORNING AS TEMPS CLIMB.
DOWNSLOPE WIND EVENT IS ONGOING WITH PEEVER HAVING GUSTED TO 61
MPH EARLIER THIS MORNING. SPEEDS ARE SLOWLY WINDING DOWN AND
EXPECT BY NOON THINGS WILL HAVE QUIETED DOWN DRAMATICALLY. PEEVER
WEB CAM DOES SHOW A PATCH OF BLOWING SNOW AND LOW VSBY...BUT LOOKS
RATHER LOCALIZED. WILL CONTINUE WITH THE SPS STATEMENT CONCERNING
STRONG WINDS. HRRR AND HOP WRF PICKING UP ON THIS NICELY AND SHOW
SPEEDS IMPROVING BY 18Z AS STRONGEST 925 MB WINDS SHIFT OFF TO THE
SOUTH AND EAST.
&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TODAY THROUGH FRIDAY
CURRENT MSAS SURFACE PRESSURE FALLS RANGE FROM 4 TO 5 MB AS A
TROUGH DROPS SOUTH OUT OF CANADA. WARM AIR ADVECTION AHEAD OF
THIS TROUGH HAS ALLOWED TEMPERATURES TO STEADY...AND IN SOME
LOCATIONS...RISE A FEW DEGREES THIS MORNING. WIND SPEEDS AT MOST
LOCATIONS ARE BETWEEN 10 AND 15 MPH...ALLOWING SCATTERED OBS
ACROSS THE REGION TO REPORT WINDCHILL READINGS WITHIN ADVISORY
CRITERIA. OTHERS ARE VERY CLOSE TO CRITERIA...SO CONTINUED THE
ADVISORY AS PLANNED. ALSO LEFT THE MENTION OF BLOWING SNOW IN THE
LEE OF THE SISSETON HILLS. THE RWIS STATION NEAR PEEVER WAS
REPORTING WIND GUSTS UP TO 40 MPH BETWEEN 11PM AND
MIDNIGHT...HOWEVER...HAVE SINCE DECREASED TO THE 20 MPH RANGE.
WEBCAMS HAVE NOT INDICATED ANY SIGNIFICANT TRAVEL ISSUES.
TODAY...WINDS WILL SWITCH AROUND TO THE WEST NORTHWEST BEHIND THE
SURFACE TROUGH. TEMPERATURES WILL BE WARMER...RELATIVELY
SPEAKING...WITH HIGHS IN THE TEENS AND 20S.
A SECONDARY COLD FRONT WILL SWEEP ACROSS THE NORTHERN PLAINS
LATER ON THURSDAY. ALTHOUGH WARM AIR ADVECTION AHEAD OF THIS FRONT
SHOULD ALLOW AFTERNOON TEMPS TO RISE INTO THE 20S AND 30S. ANY
PRECIPITATION ASSOCIATED WITH THIS FRONT APPEARS TO REMAIN NORTH
OF THIS CWA...HOWEVER FLURRIES MAY BE POSSIBLE ACROSS THE FAR
NORTHEAST CWA.
HIGH PRESSURE SLIDES ACROSS THE REGION THURSDAY NIGHT AND FRIDAY
MORNING...BEFORE RETURN FLOW TAKES OVER FRIDAY AFTERNOON.
.LONG TERM...FRIDAY NIGHT THROUGH TUESDAY
THERE CONTINUES TO BE SIGNIFICANT INCONSISTENCY WITH THE MODELS IN
THE EXTENDED PERIOD...BUT IT DOES LOOK AS THOUGH THERE IS
POTENTIAL FOR A COUPLE OF SYSTEMS TO AFFECT THE AREA. THE FIRST
WILL COME LATE FRIDAY NIGHT AND SATURDAY AS A LOW PRESSURE SYSTEM
TRACKS ACROSS THE NORTHERN PLAINS. THE GFS IS FURTHER SOUTH WITH
THE LOW...POSSIBLY BRINGING ONE TO THREE INCHES OF SNOW TO THE
NORTHEASTERN CWA...WHILE THE ECMWF IS FURTHER NORTH AND BRINGS
VERY LITTLE SNOW. THE POTENTIAL FOR THE SECOND SYSTEM COMES ON
MONDAY...BUT THE MODELS ARE VERY DIFFERENT IN THEIR DEPICTIONS.
THE GFS BRINGS A STRONGER LOW ACROSS THE CENTRAL PLAINS...THEREBY
BRINGING SNOW TO CWA. THE ECMWF HAS NO HINT WHAT SO EVER OF THE
LOW PRESSURE SYSTEM...AND THEREFORE NO PRECIPITATION. FOR THE TIME
BEING...WILL STICK CLOSE TO THE SUPERBLEND WHICH JUST HAS SOME
SCHC/CHC POPS SUNDAY NIGHT AND MONDAY.
SATURDAY WILL BE THE WARMEST DAY OF THE PERIOD WITH HIGHS IN THE
TEENS TO LOWER 20S. WILL THEN SEE COOLER AIR MOVE BACK IN WITH H85
TEMPS FALLING INTO THE UPPER TEENS TO LOWER 20S BELOW ZERO. THIS
WILL RESULT IN HIGHS MAINLY IN THE SINGLE DIGITS SUNDAY THROUGH
TUESDAY.
&&
.AVIATION...
12Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
VFR CONDITIONS WILL PREVAIL ACROSS THE AREA TODAY AND TONIGHT.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
UPDATE...TMT
SHORT TERM...SERR
LONG TERM...PARKIN
AVIATION...PARKIN
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
910 AM MST WED DEC 31 2014
&&
...MAJOR WINTER STORM WILL IMPACT CALIFORNIA AND ARIZONA TODAY AND
EARLY THURSDAY...
.SYNOPSIS...
A MAJOR WINTER STORM SYSTEM WILL AFFECT THE REGION TODAY AND EARLY
THURSDAY WITH WIDESPREAD DESERT RAIN AND MOUNTAIN SNOW. SNOW LEVELS
WILL FALL TO AS LOW AS 2000 FT FOR A PERIOD...WITH SUBSTANTIAL
SNOWFALL ACCUMULATIONS OVER MOUNTAINOUS TERRAIN. COOLER BUT DRY
WEATHER WILL RETURN BY THE END OF THE WEEK THROUGH SATURDAY.
BUILDING HIGH PRESSURE WILL MOVE IN STARTING SUNDAY ALLOWING
TEMPERATURES TO WARM BACK TO NORMAL TO SLIGHTLY ABOVE NORMAL.
&&
.DISCUSSION...
A VERY COLD STORM...FOR OUR NECK-OF-THE-WOODS...CONTINUES TO MOVE
INTO THE REGION THIS MORNING. LATEST SATELLITE IMAGERY IS NOW
SHOWING THE MAIN UPPER LOW CENTER NOW MOVING INLAND INTO EXTREME
SOUTHERN SAN DIEGO COUNTY...WITH ACCUMULATING SNOW BEING REPORTED
DOWN TO AS LOW AS 1000FT ACROSS PARTS OF SOUTHERN CA EARLIER THIS
MORNING AS THIS SYSTEM MOVED THROUGH. THE 88D RADAR IS CURRENTLY
SHOWING RAIN...AND SNOW SHOWERS NOW BREAKING OUT OVER WESTERN
MARICOPA COUNTY AS DRIER...AND COLDER AIR THAT IS POURING DOWN THE
COLORADO RIVER VALLEY SPREADS EASTWARD ACROSS SW ARIZONA HELPS TO
LOWER SNOW LEVELS ACROSS THAT REGION...WITH SNOW ALREADY BEING
REPORTED ACROSS THE WICKENBURG AREA...AND SNOW EVEN NOW BEING
REPORTED IN LAKE HAVASU CITY AS WELL. BASED ON LATEST TRENDS AND
UPDATED HRRR HI-RES RUNS...HAVE LOWERED TEMPS ACROSS THE LOWER
ELEVATIONS OF OUR CWA...AND RAISED POPS FOR THIS AFTERNOON ACROSS
SOUTH-CENTRAL AZ.
&&
.PREVIOUS DISCUSSION...
THE MAJOR WINTER STORM IS NOW MAKING ITS WAY INTO OUR REGION WITH
RAIN AND SNOW CURRENTLY FALLING ACROSS MUCH OF SOUTHEAST CALIFORNIA.
THE UPPER LOW CENTER CURRENTLY CENTERED OVER SOUTHERN CALIFORNIA IS
STARTING TO MAKE SOME EASTWARD PROGRESS AND ITS FORWARD SPEED IS
EXPECTED TO SLOW DOWN OVER THE NEXT 12 HOURS AS THE UPPER TROUGH
BECOMES MORE NEUTRALLY TILTED. AN IMPRESSIVE 125KT UPPER JET CORE
SITUATED ACROSS NORTHERN ARIZONA INTO SOUTHERN COLORADO IS PROVIDING
STRONG VERTICAL LIFT ACROSS SOUTHEAST CALIFORNIA INTO CENTRAL
ARIZONA. EXPECTING RAPID SHOWER DEVELOPMENT OVER THE NEXT SIX HOURS
TO BREAK OUT OVER SOUTHWEST AND SOUTH-CENTRAL ARIZONA IN RESPONSE TO
THE INCREASING LIFT FROM THE SOUTHEASTWARD SHIFTING JET CORE AND
RAPID MOISTENING FROM COLD AIR ALOFT MOVING IN AND FROM A STREAM OF
LOW LEVEL MOISTURE ADVECTING IN ALONG THE SOUTHERN EDGE OF THE UPPER
TROUGH. ENHANCED LIFT FROM A STRONG PVA REGION NOW OVER SOUTHERN
CALIFORNIA WILL ALSO SHIFT EASTWARD INTO SOUTHWEST ARIZONA THROUGH
THE LATE MORNING HOURS AND THROUGH SOUTH-CENTRAL ARIZONA BY LATE
THIS AFTERNOON.
THE MAIN IMPACT FROM THIS STORM SYSTEM WILL BE THE POTENTIAL FOR
ACCUMULATING SNOWS ACROSS HIGHER TERRAIN LOCATIONS...ESPECIALLY
ACROSS CENTRAL AND EASTERN ARIZONA. SNOW LEVELS WILL RAPIDLY FALL
FROM WEST TO EAST TODAY INTO THE 2K-3K FOOT RANGE BY LATE TONIGHT.
THE INITIAL BAND OF PRECIPITATION THIS MORNING ACROSS SOUTH-CENTRAL
ARIZONA WILL MAINLY FALL AS RAIN ACROSS OUR CWA...BUT AS SNOW LEVELS
FALL THROUGHOUT THE DAY...RAIN WILL CHANGE TO SNOW ACROSS THE HIGHER
TERRAIN NORTH AND EAST OF PHOENIX. THE BULK OF THE ACCUMULATING
SNOWFALL WILL START LATE THIS AFTERNOON AND LAST INTO TONIGHT WITH
POSSIBLE ACCUMULATIONS OF 2 TO 6 INCHES ABOVE 3500 FEET AND 6 TO 10
INCHES ABOVE 5000 FEET. WINDS ARE EXPECTED TO BE FAIRLY LIGHT...SO
BLOWING AND DRIFTING OF SNOW SHOULD NOT BE MUCH OF A FACTOR...BUT AS
TEMPERATURES FALL BELOW FREEZING SOMETIME THIS EVENING...SOME
ROADWAYS WILL LIKELY BECOME SNOW COVERED. WILL KEEP THE WINTER STORM
WARNING STARTING 18Z TODAY IN PLACE WITH NO CHANGES FOR ELEVATIONS
ABOVE 3500 FEET FOR ZONE 24.
LATEST MODEL QPF AMOUNTS ARE BASICALLY RIGHT IN LINE WITH THE
PREVIOUS FORECAST AND NO SIGNIFICANT ADJUSTMENTS WERE NEEDED. WITH
FAIRLY LIMITED MOISTURE...MOST LOWER DESERT AREAS FAR REMOVED FROM
THE HIGH TERRAIN SHOULD ONLY SEE A FEW HUNDREDTHS TO UP TO A TENTH
OF AN INCH. HIGHER AMOUNTS...UP TO A QUARTER INCH...SHOULD FALL FROM
PHOENIX NORTHWARD DUE TO THE STRONG UPSLOPING NATURE OF THIS EVENT.
THE BULK OF THE RAIN WILL END EVEN BY LATE THIS AFTERNOON WITH SOME
LINGERING RAIN OR SNOW TO THE NORTH AND EAST OF PHOENIX INTO
TONIGHT. DRYING AND SUBSIDENCE ALOFT SHOULD OVERTAKE MUCH OF THE
LOWER DESERTS BY THIS EVENING...BUT LOW LEVEL SOUTHERLY WINDS WILL
CONTINUE SOME UPSLOPE PRECIPITATION TO THE NORTH AND EAST OF PHOENIX
THROUGH TONIGHT BEFORE TAPERING OFF SOMETIME THURSDAY.
ATTENTION THEN TURNS TO THE INCREASING LIKELIHOOD OF A WIDESPREAD
FREEZE EVENT ACROSS THE LOWER DESERTS STARTING TONIGHT AND POSSIBLY
LASTING THROUGH FRIDAY NIGHT. THERE IS SOME DOUBT AS TO HOW QUICKLY
SKIES WILL CLEAR OUT TONIGHT ACROSS PORTIONS OF SOUTH-CENTRAL
ARIZONA...BUT THERE IS ENOUGH CONFIDENCE TO ISSUE FREEZE WARNINGS
FOR ALL BUT THE PHOENIX ZONE. WILL STRESS THE NEAR FREEZING
CONDITIONS FOR PHOENIX...SOUTHEAST CALIFORNIA...AND YUMA IN AN SPS
FOR TONIGHT. THURSDAY NIGHT SHOULD END UP BEING THE COLDEST NIGHT
WITH WIDESPREAD CLEAR TO MOSTLY CLEAR SKIES...LIGHT WINDS...AND
850MB TEMPERATURES NEAR 0C. WILL CARRY THE FREEZE WARNING AGAIN FOR
THURSDAY NIGHT WHILE ALSO INCLUDING PHOENIX IN THE WARNING. FRIDAY
NIGHT MAY ALSO END UP NEEDING SOME HEADLINES FOR THE COLD
TEMPERATURES...BUT MODELS SUGGEST SOME WARMING BEGINNING BY
THEN...SO WILL HOLD OFF ISSUING ANY HEADLINES FOR NOW.
STARTING FRIDAY...MODELS ARE IN GOOD AGREEMENT SHIFTING THE UPPER
LOW EASTWARD OUT OF OUR REGION AND ALLOWING A GRADUAL INCREASE IN
UPPER HEIGHTS. THE HIGH AMPLITUDE RIDGE THAT HAS BEEN OVER THE
EASTERN PACIFIC THE PAST SEVERAL DAYS WILL BEGIN TO TILT EASTWARD
INTO THE DESERT SOUTHWEST BY EARLY NEXT WEEK. THERE IS SOME MODEL
DISAGREEMENT AT THIS POINT...BUT OVERALL LONG RANGE MODELS SUGGEST
INCREASED HEIGHTS WHICH POINTS TO A SUBSTANTIAL WARM-UP. HIGHS
SHOULD BOUNCE BACK TO NEAR NORMAL BY NEXT MONDAY AND POSSIBLY REACH
INTO THE LOWER 70S ACROSS THE LOWER DESERTS BY THE MIDDLE OF NEXT
WEEK. DRY CONDITIONS WILL BE THE RULE AFTER THURSDAY WITH NO
SIGNIFICANT LOW PRESSURE SYSTEMS THREATENING OUR REGION THROUGH THE
MIDDLE OF NEXT WEEK.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
A COLD FRONT APPROACHING. THROUGH 16Z WED...CIGS NEAR 5 THSD AGL...
SCT R SHWRS. FROM 16Z WED TO 21Z WED...CIGS LOWERING IN LIGHT
RAIN...BECOMING BKN-OVC 30-40 THSD AGL WITH SCT LOWER CLDS. LIGHT
SOUTHWEST WIND UNDER 8 KNOTS. FROM 21Z WED TO 03Z THU. DRIER AIR
MOVING IN BEHIND THE COLD FRONT. CIGS LIFTING TO BETWEEN 4 TO 6 THSD
AGL. ISOLD LIGHT SHWRS. LIGHT WEST WIND UNDER 8 KNOTS.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA...INCLUDING KIPL AND KBLH...
COLD FRONTAL PASSAGE. THROUGH 16Z WED...CIGS 4 TO 6 THSD AGL. SCT R
SHOWERS. NORTH TO NORTHWEST WIND 10 TO 15 KNOTS. BETWEEN 16Z WED AND
01Z THU...A DRIER AIR MOVING IN. CIGS LIFTING TO BETWEEN 6 AND 8
THSD AGL. ISOLD R SHWRS. NORTH WIND 10 TO 20 KNOTS. FROM 01Z THU TO
06Z THU...SCT CLDS NEAR 10 THSD AGL. NORTH WIND 5 TO 10 KNOTS.
.FIRE WEATHER...
FRIDAY THROUGH TUESDAY...
MOSTLY CLEAR SKIES AND MUCH BELOW NORMAL TEMPERATURES ARE EXPECTED
FRIDAY THROUGH SUNDAY...WARMING SOMEWHAT MONDAY AND TUESDAY. MINIMUM
RELATIVE HUMIDITIES FRIDAY WILL RANGE FROM 20 PERCENT IN SOUTHEAST
CALIFORNIA TO 50 PERCENT IN SOUTHERN GILA COUNTY...DECREASING MONDAY
AND TUESDAY BY 15 TO 20 PERCENT RANGE AREA-WIDE. LIGHT WIND.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...FREEZE WARNING FROM 11 PM THIS EVENING TO 9 AM MST THURSDAY
AZZ020>022-026>028.
FREEZE WARNING FROM 11 PM THURSDAY TO 9 AM MST FRIDAY
AZZ020>023-026>028.
WINTER STORM WARNING FROM 11 AM THIS MORNING TO 5 PM MST
THURSDAY ABOVE 3500 FEET FOR AZZ024.
CA...WINTER WEATHER ADVISORY UNTIL 4 PM PST THIS AFTERNOON ABOVE
2000 FEET FOR CAZ030.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...PERCHA/KUHLMAN
AVIATION....VASQUEZ
FIRE WEATHER...VASQUEZ
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
430 PM EST WED DEC 31 2014
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 429 PM EST WED DEC 31 2014
WV IMAGERY AND RUC ANALYSIS INDICATED NW MID/UPPER LEVEL FLOW FROM
NW CANADA INTO THE GREAT LAKES BETWEEN A TROUGH OVER HUDSON BAY AND
A RIDGE FROM THE ERN PACIFIC INTO BC. A SHORTWAVE TROUGH WAS MOVING
THROUGH UPPER MI WITH ANOTHER WEAKER SHRTWV UPSTREAM OVER MANITOBA.
ANOTHER CLIPPER SHRTWV WAS FARTHER UPSTREAM OVER NW SASK. AT THE
SFC...STRONG WEST WINDS PREVAILED ACROSS THE REGION BETWEEN A 988 MB
LOW NEAR HUDSON BAY AND 1036 MB ARCTIC HIGH PRES INTO THE SRN
PLAINS. THE STRONGEST WINDS THIS MORNING INTO EARLY AFTERNOON ACROSS
LAKE SUPERIOR OCCURRED AS THE STRONGER PRES FALLS SLID THROUGH NRN
ONTARIO. WITH 850 MB TEMPS AROUND -19C AND CONVERGENT WRLY FLOW
DEVELOPING LES HAS INCREASED ACROSS THE KEWEENAW AS WINDS VEERED
FROM SW TO W.
TONIGHT...EXPECT THE STRONGEST LOW LEVEL CONV SUPPORTING LES TO
REMAIN OVER THE KEWEENAW. EVEN WITH A FAVORABLE POSITION OF THE DGZ
IN THE CLOUD LAYER...THE STRONGER WINDS WILL CREATE ENOUGH
COMPACTION/FRACTURING TO LIMIT SLR VALUES CLOSER TO 20/1. SO OVERALL
ACCUMULATIONS TONIGHT IN THE 2 TO 5 INCH RANGE ARE EXPECTED. WINDS
GUSTING INTO THE 30 TO 40 MPH RANGE WILL ALSO CONTINUE TO PRODUCE
CONSIDERABLE BLOWING AND DRIFTING SNOW IN OPEN AREAS WHERE OCNL
WHITEOUT CONDITIONS ARE POSSIBLE. WINDS ARE EXPECTED TO DIMINISH
OVERNIGHT REDUCING THE BLSN HAZARDS.
THU...THE NRN SASK SHRTWV TROUGH WILL BRUSH THE AREA WITH ENOUGH
700-500 MB QVECTOR CONV AND 800-600 MB FGEN TO SUPPORT AN AREA OF
LIGHT SNOW FROM NRN MN INTO NRN WI AND UPPER MI. WITH THE LACK OF
SIGNFICANT MOISTURE INFLOW/AVAILABILITY...SNOW AMOUNTS OF A HALF
INCH OR LESS ARE EXPECTED. HOWEVER...THE DEEPER MOISTURE WITH
INCREASING INVERSION HEIGHTS INTO THE AREA WILL SUPPORT GREATER LES
INTENSITY FOR THE W TO WNW FLOW LES SNOW BELTS. SINCE THE STRONGER
LOW LEVEL CONV IS EXPECTED TO SHIFT SOUTHWARD OVERALL SNOW AMOUNTS
SHOULD REMAIN IN THE 1 TO 3 INCH RANGE.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 316 PM EST WED DEC 31 2014
AN UPPER TROUGH OVER EASTERN CANADA LEAD TO COLD AIR AND LAKE
EFFECT SNOW OVER THE NORTHWEST WIND SNOW BELTS TO START THE PERIOD.
THIS LIGHT TO OCCASIONALLY MODERATE LAKE EFFECT SNOW WILL CONTINUE
IN THOSE NORTHWEST WIND BELTS ON THURSDAY NIGHT...BUT AS THE LOW
LEVEL WINDS BACK LATE THURSDAY NIGHT INTO FRIDAY MORNING...WILL
FOCUS THE POPS/SNOW TO THE WEST-NORTHWEST AREAS ON FRIDAY (AND
WESTERLY AREAS LATE FRIDAY AFTERNOON). WHILE LAKE INDUCED
EQUILIBRIUM LEVELS WILL BE AROUND 8KFT...THERE ARE SOME CONCERNS IN
THE AMOUNT OF MOISTURE AVAILABLE AS SUBSIDENCE AND DRIER AIR ARRIVE
THURSDAY NIGHT FROM A HIGH MOVING SOUTHEAST INTO MINNESOTA.
THUS...WILL STICK WITH A DUSTING TO 3-4IN EVERY 12HRS THROUGH
FRIDAY...WITH THE HIGHEST AMOUNTS OVER THE EAST WITH THE LONGER
FETCH AND SOME INDICATIONS OF A LINGERING TROUGH AIDING
CONVERGENCE TOWARDS WHITEFISH POINT. THE HIGH WILL SHIFT SOUTHEAST
OF THE AREA ON FRIDAY EVENING...BACKING WINDS TO THE SOUTHWEST AND
ONLY LEAVING LAKE EFFECT SNOW OVER THE KEWEENAW FOR FRIDAY NIGHT.
THE FOCUS THEN TURNS TO THE INTERACTION AND PHASING OF THE SPLIT
FLOW FOR THE START OF THE WEEKEND. MODELS SEEM TO COMING INTO
BETTER AGREEMENT ON THE OVERALL IDEA FOR THE WEEKEND...ALTHOUGH
THERE ARE STILL SMALLER DIFFERENCES THAT COULD HAVE AN IMPACT ON
THE AMOUNT OF SNOW SEEN OVER PARTS OF THE U.P. THERE ARE TWO
FEATURES AT PLAY FOR THIS WEEKEND...THE FIRST IS THE REMNANTS OF
THE UPPER LOW PRODUCING SNOW OVER THE SOUTHWEST CONUS TODAY AND THE
SECOND FEATURE IS A SHORTWAVE CURRENTLY OVER THE ALEUTIANS ISLANDS
AND DROPPING SOUTHEAST INTO THE NORTHERN ROCKIES ON FRIDAY NIGHT.
THIS WILL LEAD TO A LOW DEVELOPING IN THE LEE OF THE NORTHERN
ROCKIES AND THEN MOVING EAST INTO THE DAKOTAS AND WESTERN MINNESOTA
BY SATURDAY MORNING. EXPECT SNOW TO SPREAD EAST AHEAD OF THIS LOW
AND INTO THE NORTHWEST HALF OF THE CWA...ASSOCIATED WITH STRONG MID
LEVEL WARM AIR ADVECTION. WHILE THE HEAVIEST SNOW APPEARS TO OCCUR
OVER LAKE SUPERIOR...WILL SHOW SOME LIKELY POPS OVER AND AROUND THE
KEWEENAW PENINSULA FOR SATURDAY. AS THAT IS OCCURRING...THE
NORTHERN SHORTWAVE WILL CONTINUE TO DIVE SOUTHEAST AND PHASE WITH
THE SOUTHERN UPPER LOW AND LEAD TO BOTH EJECTING NORTHEAST THROUGH
THE LOWER GREAT LAKES REGION SATURDAY NIGHT INTO SUNDAY. AS
EXPECTED IN THESE PHASING EVENTS...EACH MODEL RUN GIVES A SLIGHTLY
DIFFERENT IDEA ON THE EVOLUTION OF THE PHASED FEATURES AND IN TURN
THE SURFACE FEATURES. OVERALL...THE GENERAL IDEA IS FOR A
STRENGTHENING LOW TO LIFT NORTHEAST THROUGH SOUTHEAST LOWER
MICHIGAN ON SATURDAY NIGHT AND THEN INTO QUEBEC ON SUNDAY. WITH
THAT TRACK...WOULD EXPECT MUCH OF THE SYNOPTIC
FORCING/PRECIPITATION ASSOCIATED WITH THOSE FEATURES TO MISS THE
U.P....BUT WOULD STILL EXPECT AT LEAST SOME LAKE ENHANCEMENT AS THE
WINDS TURN TO THE NORTHWEST BEHIND THE ELONGATED SURFACE TROUGH
STRETCHING NORTH OVER EASTERN LAKE SUPERIOR LATE SATURDAY NIGHT.
INITIALLY...WOULDN/T EXPECT THE LAKE ENHANCEMENT TO AMOUNT TO TOO
HIGH OF SNOWFALL AMOUNTS ON SATURDAY NIGHT...BUT AS MUCH COLDER AIR
MOVES INTO THE AREA (850MB TEMPS FALLING TO -25C BY 00Z MONDAY) AND
THE DEEPER MOISTURE IS STILL PRESENT FROM THE DEPARTING
SYSTEM...WOULD EXPECT THE LAKE ENHANCEMENT/EFFECT SNOW TO TAKE OFF
ON SUNDAY IN THE NORTHWEST WIND SNOW BELTS. WILL TREND POPS UP TO
DEFINITE VALUES DURING THIS PERIOD AND CONTINUE TO MENTION
MODERATE/HEAVY SNOW WORDING IN THE HWO.
BEHIND THE LOW...EXPECT THE FIRST PART OF THE WORK WEEK TO BE VERY
COLD WITH CONTINUED LAKE EFFECT SNOW. THE CANADIAN UPPER TROUGH
WILL SAG SOUTH INTO THE GREAT LAKES REGION AND KEEP THE COLD AIR IN
PLACE (850MB TEMPS IN THE LOW 20C BELOW ZERO)...WITH ANOTHER
SHORTWAVE MOVING THROUGH ON MONDAY NIGHT POTENTIALLY PULLING 850MB
TEMPERATURES CLOSE TO -30C FOR TUESDAY. THAT WILL LEAD TO VERY COLD
HIGH TEMPERATURES FOR MONDAY/TUESDAY...WITH SOME LOCATIONS OVER THE
INTERIOR WEST EVEN STRUGGLING TO RISE ABOVE 0. IN FACT...LOOKING AT
THE 00Z ECMWF ENSEMBLE MEMBERS AT KSAW AND OTHER SITES IN THE
WESTERN/CENTRAL U.P....THERE MAY END UP BEING A 24-36 HOUR PERIOD OF
SUB ZERO TEMPERATURES LATE SUNDAY NIGHT THROUGH AT LEAST TUESDAY
MORNING. THE COMBINATION OF THE COLD TEMPERATURES AT NIGHT (SINGLE
DIGITS AND TEENS BELOW ZERO) AND WINDS IN THE 5-10MPH RANGE WILL
LEAD TO LOW WIND CHILL VALUES MONDAY/TUESDAY MORNINGS AND
POTENTIALLY EVENING WEDNESDAY MORNING. AS LONG AS THE WIND SPEEDS
STAY UP...WOULD EXPECT THE NEED FOR WIND CHILL ADVISORIES AT A
MINIMUM AND WILL CONTINUE TO ADDRESS IN THE HWO.
AS FOR LAKE EFFECT DURING THE FIRST PART OF NEXT WEEK...EXPECT WINDS
TO BACK TO THE WEST ON MONDAY AND WILL FOCUS THE LAKE EFFECT POPS
IN THOSE AREAS. WITH THE AMOUNT OF COLD AIR IN PLACE...VERY LITTLE
OF THE CLOUD LAYER WILL BE IN THE DGZ AND MOST WILL BE ABOVE
IT...WHICH LEADS TO MORE COLUMN/PLATE SNOWFLAKES AND WOULD EXPECT
ACCUMULATIONS TO BE LIMITED. WINDS WILL SHIFT MORE TO THE NORTHWEST
ON TUESDAY BEHIND THAT NEXT SHORTWAVE AND WILL TREND POPS TO THAT
FAVORED WIND DIRECTION. WITH THE AMOUNT OF COLD AIR...THERE
SHOULDN/T BE MUCH OF AN ISSUE FOR AT LEAST SOME LAKE EFFECT...SO
DID TREND POPS UP TO LIKELY-DEFINITE VALUES EVEN THOUGH AMOUNTS
SHOULD BE LIMITED. AS THE UPPER TROUGH SHIFTS EAST ON WEDNESDAY AND
THROUGH THE END OF THE WORK WEEK...THE UPPER GREAT LAKES REGION
SHOULD SEE A MODERATION IN THEIR TEMPERATURES TOWARDS MORE NORMAL
VALUES TOWARDS THE END OF NEXT WEEK. LOOKING AT THE 00Z ECMWF
ENSEMBLE MEAN FOR DAYS 9-15...IT SHOWS MORE OF A ZONAL FLOW ACROSS
THE CONUS...WHICH WOULD TRANSLATE TO MORE NORMAL OR EVEN SLIGHTLY
ABOVE NORMAL TEMPERATURES HEADING INTO THE MIDDLE OF JANUARY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1243 PM EST WED DEC 31 2014
GUSTY WEST WINDS OVER 30 KNOTS WITH BLSN AND LES ACROSS THE KEWEENAW
DROP VSBY INTO THE LIFR/VLIFR RANGE THIS AFTERNOON INTO TONIGHT.
THERE MAY BE SOME IMPROVEMENT BY LATE TONIGHT OR EARLY THURSDAY AS
WINDS DIMINISH AND VEER MORE TO THE NW. OTHERWISE...MAINLY VFR
CONDITIONS AT IWD MAY GIVE WAY TO SOME MVFR CIGS LATE TONIGHT AS LOW
LEVEL WINDS ACROSS THE LAKE VEER MORE TO THE NW. THE SW TO W FLOW AT
SAW LATE TONIGHT WILL FAVOR CONTINUATION OF VFR CONDITIONS.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 429 PM EST WED DEC 31 2014
LAKE SUPERIOR WILL BE STUCK BETWEEN VERY STRONG HIGH PRESSURE ACROSS
THE S PLAINS AND A DEEP HUDSON BAY LOW TODAY. GALES OF 35-45KTS WILL
CONTINUE BEFORE SLOWLY DIMINISHING TO 35KTS LATE TONIGHT INTO
THURSDAY MORNING OUT OF THE W-NW. GIVEN PLENTY OF COLD AIR...AND
STRONG WINDS...HEAVY FREEZING SPRAY WILL ALSO BE A CONCERN INTO
THURSDAY.
LOOK FOR THE TROUGH OVER LAKE SUPERIOR TO DEEPEN TONIGHT THROUGH
THURSDAY. THE HUDSON BAY LOW WILL SHIFT AND WEAKEN ACROSS N QUEBEC
THURSDAY NIGHT...ALLOWING THE TROUGH ACROSS LAKE SUPERIOR TO WEAKEN
AS WELL. HIGH PRESSURE SINKING ACROSS MANITOBA AND MINNESOTA
THURSDAY NIGHT WILL BUILD RIDGE ACROSS LAKE SUPERIOR ON FRIDAY AS IT
PROGRESSES ACROSS THE REMAINDER OF THE GREAT LAKES. A WEAK TROUGH
WILL LIKELY LINGER ACROSS MAINLY E LAKE SUPERIOR DURING THIS TIME.
EXPECT A LOW NEAR MONTANA ON FRIDAY TO TRACK ACROSS THE N AND
CENTRAL PLAINS SATURDAY MORNING...AND THE MID MISSISSIPPI VALLEY
SATURDAY AFTERNOON...BEFORE DEEPENING NORTHEASTWARD ACROSS THE LOWER
GREAT LAKES AND QUEBEC LATE SATURDAY NIGHT INTO SUNDAY. THIS WILL
BRING A TROUGH THROUGH THE AREA SATURDAY NIGHT INTO SUNDAY...ALONG
WITH THE POTENTIAL FOR N-NW GALES. HEAVY FREEZING SPRAY WILL
ALSO MAKE A RETURN ACROSS MUCH OF LAKE SUPERIOR.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY UNTIL 1 PM EST THURSDAY FOR MIZ001-003.
LAKESHORE FLOOD ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR MIZ001-
003.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 4 AM EST /3 AM CST/ THURSDAY
FOR LSZ162-240>245-248>251-263>267.
GALE WARNING UNTIL 10 AM EST THURSDAY FOR LSZ266-267.
GALE WARNING UNTIL 7 AM EST /6 AM CST/ THURSDAY FOR LSZ162-
241>248-263>265.
HEAVY FREEZING SPRAY WARNING UNTIL 1 AM EST THURSDAY FOR LSZ246-
247.
GALE WARNING UNTIL 7 AM EST THURSDAY FOR LSZ249>251.
LAKE MICHIGAN...
HEAVY FREEZING SPRAY WARNING UNTIL 1 AM EST THURSDAY FOR LMZ221-
248-250.
GALE WARNING UNTIL 1 AM EST THURSDAY FOR LMZ221-250.
&&
$$
SHORT TERM...JLB
LONG TERM...SRF
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
218 PM EST WED DEC 31 2014
LATEST UPDATE...
HYDRO
.SYNOPSIS...
ISSUED AT 1210 PM EST WED DEC 31 2014
SNOW SHOWERS WILL CONTINUE THROUGH THIS AFTERNOON BUT
ACCUMULATIONS WILL BE LIGHT. IT WILL STAY COLD AND WINDY TONIGHT.
A STORM WITH SNOW OR MIXED PRECIPITATION IS EXPECTED THIS WEEKEND.
&&
.UPDATE...
ISSUED AT 1210 PM EST WED DEC 31 2014
BASED ON CURRENT RADAR TRENDS AND MODEL GUIDANCE...THE POPS HAVE
BEEN INCREASED FOR THIS AFTERNOON AS WEST FLOW LAKE EFFECT SNOW
SHOWERS WILL CONTINUE.
UPDATE ISSUED AT 611 AM EST WED DEC 31 2014
I DISPLACED THE HIGHEST POP AND GREATEST SNOW ACCUMULATIONS INLAND
TO NEAR US-131 INSTEAD OF NEAR THE LAKE SHORE. CURRENTLY (6 AM)
THE LOWEST REPORTED VISIBILITIES ARE LOCATIONS NEAR US-131
(RQB...FFX...GRR TO LAN ) AND NOT BY THE LAKE SHORE. ALL STATIONS
NEAR THE LAKE SHORE HAVE HAD VISIBILITIES GREATER THAN 6 MILES SINCE
I CAME TO WORK AROUND MIDNIGHT. THE HRRR AND NAM ALSO SHOW THE
LOCATION OF THE HIGHEST ACCUMULATION NEAR AND NORTH OF I-96...BY
US-131 INTO THIS AFTERNOON. THE REASON FOR THIS IS THE WINDS IN
THE CLOUD LAYER INCREASING TO 40 KNOT. THOSE STRONG OF WIND ALWAYS
BLOW THE HEAVIEST SNOW SHOWERS INLAND. THERE SHOULD BE DECREASE IN
THE SNOW SHOWER ACTIVITY THIS AFTERNOON AS MID LEVEL TEMPERATURES
START TO RISE AND SHORTWAVE CAUSING THE CURRENT BUST OF ACTIVITY
MOVES EAST OF THE AREA.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 326 AM EST WED DEC 31 2014
FORECAST CONCERNS DEAL WITH LAKE EFFECT SNOW SHOWERS TODAY AND WINDS
THIS AFTERNOON.
RADAR SHOWS SHSN CONTINUING ACROSS THE WESTERN CWA AS THE CORE OF
THE COLD AIR MOVES THROUGH. H8 TEMPS NEAR -20C ARE PROVIDING GOOD
INSTABILITY OVER THE LAKE. EVEN THOUGH MOISTURE IS SHALLOW...WE/RE
SEEING SOME LIGHT SNOW. ACCUMS ARE ONLY A FEW TENTHS OF AN INCH
THOUGH DUE TO A LOW AND SHALLOW DGZ WITH LIMITED LIFT WITHIN THAT
ZONE. AS THE CORE OF THE COLD AIR MOVES EAST...THE SHSN WILL
DIMINISH LATE TODAY. WINDS WILL ALSO INCREASE AS THE NEXT COLD FRONT
DROPS SOUTH INTO THE NORTHERN GREAT LAKES. WIND PROFILES IN THE FAR
NW CWA SUGGEST WE COULD SEE WIND GUSTS IN EXCESS OF 45 KTS...SO WE
HAVE ISSUED A WIND ADVISORY FOR MASON COUNTY FROM THIS AFTERNOON
THROUGH TONIGHT.
A STRONG SHORT WAVE WILL ACCOMPANY THE COLD FRONT THURSDAY AND
THURSDAY NIGHT AS IT MOVES OVER NORTHERN LOWER MICHIGAN. SOME LIGHT
SNOW IS POSSIBLE WITH THE SYSTEM WITH BOUNDARY LAYER RH AROUND 90
PERCENT. OVERALL MOISTURE IS DEEPER WITH THIS SYSTEM BUT THE MAIN
AREA OF LIFT IS WELL BELOW THE DGZ WHICH IS PROGGED AOA 10K FT. THIS
WILL CUT DOWN ON ACCUMS QUITE A BIT. PLACED HIGHEST POPS OVER THE
NRN CWA.
.LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY)
ISSUED AT 326 AM EST WED DEC 31 2014
MY FORECAST CONFIDENCE FOR A SYSTEM MOVING THROUGH SOUTHERN LOWER
MICHIGAN SATURDAY INTO EARLY SUNDAY CONTINUES TO INCREASE. IT IS
LOOKING MORE AND MORE LIKE MOSTLY SNOW...WITH MIXED PRECIPITATION IN
THE I-69 AREA SATURDAY EVENING. BEHIND THAT MUCH COLDER AIR MOVES IN
THAT WILL REMAIN IN PLACE MOST OF NEXT WEEK. LAKE EFFECT SNOW WILL
BE ACTIVE THROUGH THE SUNDAY TO TUESDAY TIME FRAME.
THE SATURDAY STORM SYSTEM RESULTS FROM THE PHASING OF THREE SYSTEMS.
WHAT PHASES IS THE CLOSED UPPER LOW CURRENTLY OVER THE SOUTHWEST
UNITED STATES....AND A DIGGING ARCTIC SHORTWAVE AND A PACIFIC
SHORTWAVE. THE PHASING OF THESE THREE SYSTEMS HAPPENS ON SATURDAY AS
THE STORM APPROACHES OUR AREA. THERE IS STILL SOME QUESTION AS TO
THE TRACK AND HOW MUCH WARM AIR COMES WEST OF THE SYSTEM. HOWEVER...
UNLIKE THE SYSTEM ON CHRISTMAS...THIS SYSTEM HAS A LOT OF COLD AIR
TO WORK WITH SO THERE SHOULD BE MUCH LESS OF AN ISSUE WITH GETTING A
SIGNIFICANT AMOUNT OF THE STORMS PRECIPITATION IN OUR CWA TO BE SNOW
GIVEN THE TRACK IS THROUGH SOUTHEAST MICHIGAN. I STILL ALLOWED FOR
SLEET...FREEZING RAIN TO MIX IN OVER MOST AREAS NEAR AND EAST OF
GRAND RAPIDS SATURDAY AFTERNOON. THIS WILL HAVE TO BE ADJUSTED AS
THE STORM TRACK BECOMES MORE CERTAIN.
BEHIND THE SYSTEM WE TO HAVE THE ISSUE WITH SPLITTING POLAR VORTEX.
THAT WILL ASSURES A SIGNIFICANT PUSH OF MUCH COLDER AIR BEHIND THE
SYSTEM SATURDAY NIGHT. BOTH THE ECMWF AND GFS HAVE 850 TEMPS
FALLING TO NEAR -25C IN THE MONDAY-TUESDAY TIME FRAME. GIVEN THAT
AMOUNT OF COLD AIR AND A SERIES OF SHORTWAVES ON THE NORTHERN BRANCH
OF THE POLAR JET..LITTLE QUESTION IN MY MIND...LAKE EFFECT SNOW WILL
BE ON-GOING THROUGH THE MIDDLE OF NEXT WEEK.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 326 AM EST WED DEC 31 2014
FORECAST CONCERNS DEAL WITH LAKE EFFECT SNOW SHOWERS TODAY AND WINDS
THIS AFTERNOON.
RADAR SHOWS SHSN CONTINUING ACROSS THE WESTERN CWA AS THE CORE OF
THE COLD AIR MOVES THROUGH. H8 TEMPS NEAR -20C ARE PROVIDING GOOD
INSTABILITY OVER THE LAKE. EVEN THOUGH MOISTURE IS SHALLOW...WE/RE
SEEING SOME LIGHT SNOW. ACCUMS ARE ONLY A FEW TENTHS OF AN INCH
THOUGH DUE TO A LOW AND SHALLOW DGZ WITH LIMITED LIFT WITHIN THAT
ZONE. AS THE CORE OF THE COLD AIR MOVES EAST...THE SHSN WILL
DIMINISH LATE TODAY. WINDS WILL ALSO INCREASE AS THE NEXT COLD FRONT
DROPS SOUTH INTO THE NORTHERN GREAT LAKES. WIND PROFILES IN THE FAR
NW CWA SUGGEST WE COULD SEE WIND GUSTS IN EXCESS OF 45 KTS...SO WE
HAVE ISSUED A WIND ADVISORY FOR MASON COUNTY FROM THIS AFTERNOON
THROUGH TONIGHT.
A STRONG SHORT WAVE WILL ACCOMPANY THE COLD FRONT THURSDAY AND
THURSDAY NIGHT AS IT MOVES OVER NORTHERN LOWER MICHIGAN. SOME LIGHT
SNOW IS POSSIBLE WITH THE SYSTEM WITH BOUNDARY LAYER RH AROUND 90
PERCENT. OVERALL MOISTURE IS DEEPER WITH THIS SYSTEM BUT THE MAIN
AREA OF LIFT IS WELL BELOW THE DGZ WHICH IS PROGGED AOA 10K FT. THIS
WILL CUT DOWN ON ACCUMS QUITE A BIT. PLACED HIGHEST POPS OVER THE
NRN CWA.
.LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY)
ISSUED AT 326 AM EST WED DEC 31 2014
MY FORECAST CONFIDENCE FOR A SYSTEM MOVING THROUGH SOUTHERN LOWER
MICHIGAN SATURDAY INTO EARLY SUNDAY CONTINUES TO INCREASE. IT IS
LOOKING MORE AND MORE LIKE MOSTLY SNOW...WITH MIXED PRECIPITATION IN
THE I-69 AREA SATURDAY EVENING. BEHIND THAT MUCH COLDER AIR MOVES IN
THAT WILL REMAIN IN PLACE MOST OF NEXT WEEK. LAKE EFFECT SNOW WILL
BE ACTIVE THROUGH THE SUNDAY TO TUESDAY TIME FRAME.
THE SATURDAY STORM SYSTEM RESULTS FROM THE PHASING OF THREE SYSTEMS.
WHAT PHASES IS THE CLOSED UPPER LOW CURRENTLY OVER THE SOUTHWEST
UNITED STATES....AND A DIGGING ARCTIC SHORTWAVE AND A PACIFIC
SHORTWAVE. THE PHASING OF THESE THREE SYSTEMS HAPPENS ON SATURDAY AS
THE STORM APPROACHES OUR AREA. THERE IS STILL SOME QUESTION AS TO
THE TRACK AND HOW MUCH WARM AIR COMES WEST OF THE SYSTEM. HOWEVER...
UNLIKE THE SYSTEM ON CHRISTMAS...THIS SYSTEM HAS A LOT OF COLD AIR
TO WORK WITH SO THERE SHOULD BE MUCH LESS OF AN ISSUE WITH GETTING A
SIGNIFICANT AMOUNT OF THE STORMS PRECIPITATION IN OUR CWA TO BE SNOW
GIVEN THE TRACK IS THROUGH SOUTHEAST MICHIGAN. I STILL ALLOWED FOR
SLEET...FREEZING RAIN TO MIX IN OVER MOST AREAS NEAR AND EAST OF
GRAND RAPIDS SATURDAY AFTERNOON. THIS WILL HAVE TO BE ADJUSTED AS
THE STORM TRACK BECOMES MORE CERTAIN.
BEHIND THE SYSTEM WE TO HAVE THE ISSUE WITH SPLITTING POLAR VORTEX.
THAT WILL ASSURES A SIGNIFICANT PUSH OF MUCH COLDER AIR BEHIND THE
SYSTEM SATURDAY NIGHT. BOTH THE ECMWF AND GFS HAVE 850 TEMPS
FALLING TO NEAR -25C IN THE MONDAY-TUESDAY TIME FRAME. GIVEN THAT
AMOUNT OF COLD AIR AND A SERIES OF SHORTWAVES ON THE NORTHERN BRANCH
OF THE POLAR JET..LITTLE QUESTION IN MY MIND...LAKE EFFECT SNOW WILL
BE ON-GOING THROUGH THE MIDDLE OF NEXT WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1221 PM EST WED DEC 31 2014
MOSTLY MVFR CONDITIONS EXISTED ACROSS THE REGION EARLY THIS
AFTERNOON...HOWEVER SCATTERED AREAS OF IFR PERSISTED IN LAKE
EFFECT SNOW SHOWERS. NOT MUCH CHANGE IS EXPECTED UNTIL PERHAPS MID
THURSDAY MORNING. MEAN LOW LEVEL WINDS ARE EXPECTED TO REMAIN
240-260 AND THIS WILL FAVOR MKG AND GRR WITH PERIODIC SNOW SHOWERS
AND OCCASIONAL IFR VSBYS. DRIER AIR DOES NOT ARRIVE UNTIL THURSDAY
MORNING...WHEN THE FREQUENCY OF THE SNOW SHOWERS SHOULD FINALLY
DIMINISH. THE REST OF THE SW MI TAF SITES SHOULD SEE A MIX OF MVFR
AND VFR.
WSW WINDS WILL CONTINUE TO GUST 20-30 KNOTS THROUGH THE NEXT 24
HOURS.
&&
.MARINE...
ISSUED AT 1210 PM EST WED DEC 31 2014
KEPT THE MARINE HEADLINES UNCHANGED. ADDED FREEZING SPRAY TO THE
FORECAST BUT DID NOT ISSUE ADVISORY OR WARNING BASED ON
COORDINATION WITH SURROUNDING OFFICES.
&&
.HYDROLOGY...
ISSUED AT 218 PM EST WED DEC 31 2014
ICE DEVELOPMENT ON SOME RIVERS AND STREAMS OVER THE NEXT COUPLE
OF DAYS. WARMER TEMPS EXPECTED FRI-SUN WITH DAYTIME HIGHS IN THE
UPPER 20S TO LOWER 30S. ANOTHER SHOT OF ARCTIC AIR ARRIVES LATE IN
THE WEEKEND WITH LOWS SUNDAY NIGHT IN THE SINGLE DIGITS. HIGHS
ONLY IN THE TEENS ON MONDAY.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WIND ADVISORY UNTIL 6 AM EST THURSDAY FOR MIZ037.
LM...GALE WARNING UNTIL 6 AM EST THURSDAY FOR LMZ844>849.
&&
$$
UPDATE...OSTUNO
SYNOPSIS...OSTUNO
SHORT TERM...93
LONG TERM...WDM
AVIATION...JK
HYDROLOGY...EBW
MARINE...OSTUNO
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1221 PM EST WED DEC 31 2014
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 1210 PM EST WED DEC 31 2014
SNOW SHOWERS WILL CONTINUE THROUGH THIS AFTERNOON BUT
ACCUMULATIONS WILL BE LIGHT. IT WILL STAY COLD AND WINDY TONIGHT.
A STORM WITH SNOW OR MIXED PRECIPITATION IS EXPECTED THIS WEEKEND.
&&
.UPDATE...
ISSUED AT 1210 PM EST WED DEC 31 2014
BASED ON CURRENT RADAR TRENDS AND MODEL GUIDANCE...THE POPS HAVE
BEEN INCREASED FOR THIS AFTERNOON AS WEST FLOW LAKE EFFECT SNOW
SHOWERS WILL CONTINUE.
UPDATE ISSUED AT 611 AM EST WED DEC 31 2014
I DISPLACED THE HIGHEST POP AND GREATEST SNOW ACCUMULATIONS INLAND
TO NEAR US-131 INSTEAD OF NEAR THE LAKE SHORE. CURRENTLY (6 AM)
THE LOWEST REPORTED VISIBILITIES ARE LOCATIONS NEAR US-131
(RQB...FFX...GRR TO LAN ) AND NOT BY THE LAKE SHORE. ALL STATIONS
NEAR THE LAKE SHORE HAVE HAD VISIBILITIES GREATER THAN 6 MILES SINCE
I CAME TO WORK AROUND MIDNIGHT. THE HRRR AND NAM ALSO SHOW THE
LOCATION OF THE HIGHEST ACCUMULATION NEAR AND NORTH OF I-96...BY
US-131 INTO THIS AFTERNOON. THE REASON FOR THIS IS THE WINDS IN
THE CLOUD LAYER INCREASING TO 40 KNOT. THOSE STRONG OF WIND ALWAYS
BLOW THE HEAVIEST SNOW SHOWERS INLAND. THERE SHOULD BE DECREASE IN
THE SNOW SHOWER ACTIVITY THIS AFTERNOON AS MID LEVEL TEMPERATURES
START TO RISE AND SHORTWAVE CAUSING THE CURRENT BUST OF ACTIVITY
MOVES EAST OF THE AREA.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 326 AM EST WED DEC 31 2014
FORECAST CONCERNS DEAL WITH LAKE EFFECT SNOW SHOWERS TODAY AND WINDS
THIS AFTERNOON.
RADAR SHOWS SHSN CONTINUING ACROSS THE WESTERN CWA AS THE CORE OF
THE COLD AIR MOVES THROUGH. H8 TEMPS NEAR -20C ARE PROVIDING GOOD
INSTABILITY OVER THE LAKE. EVEN THOUGH MOISTURE IS SHALLOW...WE/RE
SEEING SOME LIGHT SNOW. ACCUMS ARE ONLY A FEW TENTHS OF AN INCH
THOUGH DUE TO A LOW AND SHALLOW DGZ WITH LIMITED LIFT WITHIN THAT
ZONE. AS THE CORE OF THE COLD AIR MOVES EAST...THE SHSN WILL
DIMINISH LATE TODAY. WINDS WILL ALSO INCREASE AS THE NEXT COLD FRONT
DROPS SOUTH INTO THE NORTHERN GREAT LAKES. WIND PROFILES IN THE FAR
NW CWA SUGGEST WE COULD SEE WIND GUSTS IN EXCESS OF 45 KTS...SO WE
HAVE ISSUED A WIND ADVISORY FOR MASON COUNTY FROM THIS AFTERNOON
THROUGH TONIGHT.
A STRONG SHORT WAVE WILL ACCOMPANY THE COLD FRONT THURSDAY AND
THURSDAY NIGHT AS IT MOVES OVER NORTHERN LOWER MICHIGAN. SOME LIGHT
SNOW IS POSSIBLE WITH THE SYSTEM WITH BOUNDARY LAYER RH AROUND 90
PERCENT. OVERALL MOISTURE IS DEEPER WITH THIS SYSTEM BUT THE MAIN
AREA OF LIFT IS WELL BELOW THE DGZ WHICH IS PROGGED AOA 10K FT. THIS
WILL CUT DOWN ON ACCUMS QUITE A BIT. PLACED HIGHEST POPS OVER THE
NRN CWA.
.LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY)
ISSUED AT 326 AM EST WED DEC 31 2014
MY FORECAST CONFIDENCE FOR A SYSTEM MOVING THROUGH SOUTHERN LOWER
MICHIGAN SATURDAY INTO EARLY SUNDAY CONTINUES TO INCREASE. IT IS
LOOKING MORE AND MORE LIKE MOSTLY SNOW...WITH MIXED PRECIPITATION IN
THE I-69 AREA SATURDAY EVENING. BEHIND THAT MUCH COLDER AIR MOVES IN
THAT WILL REMAIN IN PLACE MOST OF NEXT WEEK. LAKE EFFECT SNOW WILL
BE ACTIVE THROUGH THE SUNDAY TO TUESDAY TIME FRAME.
THE SATURDAY STORM SYSTEM RESULTS FROM THE PHASING OF THREE SYSTEMS.
WHAT PHASES IS THE CLOSED UPPER LOW CURRENTLY OVER THE SOUTHWEST
UNITED STATES....AND A DIGGING ARCTIC SHORTWAVE AND A PACIFIC
SHORTWAVE. THE PHASING OF THESE THREE SYSTEMS HAPPENS ON SATURDAY AS
THE STORM APPROACHES OUR AREA. THERE IS STILL SOME QUESTION AS TO
THE TRACK AND HOW MUCH WARM AIR COMES WEST OF THE SYSTEM. HOWEVER...
UNLIKE THE SYSTEM ON CHRISTMAS...THIS SYSTEM HAS A LOT OF COLD AIR
TO WORK WITH SO THERE SHOULD BE MUCH LESS OF AN ISSUE WITH GETTING A
SIGNIFICANT AMOUNT OF THE STORMS PRECIPITATION IN OUR CWA TO BE SNOW
GIVEN THE TRACK IS THROUGH SOUTHEAST MICHIGAN. I STILL ALLOWED FOR
SLEET...FREEZING RAIN TO MIX IN OVER MOST AREAS NEAR AND EAST OF
GRAND RAPIDS SATURDAY AFTERNOON. THIS WILL HAVE TO BE ADJUSTED AS
THE STORM TRACK BECOMES MORE CERTAIN.
BEHIND THE SYSTEM WE TO HAVE THE ISSUE WITH SPLITTING POLAR VORTEX.
THAT WILL ASSURES A SIGNIFICANT PUSH OF MUCH COLDER AIR BEHIND THE
SYSTEM SATURDAY NIGHT. BOTH THE ECMWF AND GFS HAVE 850 TEMPS
FALLING TO NEAR -25C IN THE MONDAY-TUESDAY TIME FRAME. GIVEN THAT
AMOUNT OF COLD AIR AND A SERIES OF SHORTWAVES ON THE NORTHERN BRANCH
OF THE POLAR JET..LITTLE QUESTION IN MY MIND...LAKE EFFECT SNOW WILL
BE ON-GOING THROUGH THE MIDDLE OF NEXT WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1221 PM EST WED DEC 31 2014
MOSTLY MVFR CONDITIONS EXISTED ACROSS THE REGION EARLY THIS
AFTERNOON...HOWEVER SCATTERED AREAS OF IFR PERSISTED IN LAKE
EFFECT SNOW SHOWERS. NOT MUCH CHANGE IS EXPECTED UNTIL PERHAPS MID
THURSDAY MORNING. MEAN LOW LEVEL WINDS ARE EXPECTED TO REMAIN
240-260 AND THIS WILL FAVOR MKG AND GRR WITH PERIODIC SNOW SHOWERS
AND OCCASIONAL IFR VSBYS. DRIER AIR DOES NOT ARRIVE UNTIL THURSDAY
MORNING...WHEN THE FREQUENCY OF THE SNOW SHOWERS SHOULD FINALLY
DIMINISH. THE REST OF THE SW MI TAF SITES SHOULD SEE A MIX OF MVFR
AND VFR.
WSW WINDS WILL CONTINUE TO GUST 20-30 KNOTS THROUGH THE NEXT 24
HOURS.
&&
.MARINE...
ISSUED AT 1210 PM EST WED DEC 31 2014
KEPT THE MARINE HEADLINES UNCHANGED. ADDED FREEZING SPRAY TO THE
FORECAST BUT DID NOT ISSUE ADVISORY OR WARNING BASED ON
COORDINATION WITH SURROUNDING OFFICES.
&&
.HYDROLOGY...
ISSUED AT 326 AM EST WED DEC 31 2014
COLD TEMPS WILL CONTINUE TO AID IN ICE DEVELOPMENT ON AREA
WATERWAYS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WIND ADVISORY UNTIL 6 AM EST THURSDAY FOR MIZ037.
LM...GALE WARNING UNTIL 6 AM EST THURSDAY FOR LMZ844>849.
&&
$$
UPDATE...OSTUNO
SYNOPSIS...OSTUNO
SHORT TERM...93
LONG TERM...WDM
AVIATION...JK
HYDROLOGY...93
MARINE...OSTUNO
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1210 PM EST WED DEC 31 2014
LATEST UPDATE...
UPDATE/SYNOPSIS/MARINE
.SYNOPSIS...
ISSUED AT 1210 PM EST WED DEC 31 2014
SNOW SHOWERS WILL CONTINUE THROUGH THIS AFTERNOON BUT
ACCUMULATIONS WILL BE LIGHT. IT WILL STAY COLD AND WINDY TONIGHT.
A STORM WITH SNOW OR MIXED PRECIPITATION IS EXPECTED THIS WEEKEND.
&&
.UPDATE...
ISSUED AT 1210 PM EST WED DEC 31 2014
BASED ON CURRENT RADAR TRENDS AND MODEL GUIDANCE...THE POPS HAVE
BEEN INCREASED FOR THIS AFTERNOON AS WEST FLOW LAKE EFFECT SNOW
SHOWERS WILL CONTINUE.
UPDATE ISSUED AT 611 AM EST WED DEC 31 2014
I DISPLACED THE HIGHEST POP AND GREATEST SNOW ACCUMULATIONS INLAND
TO NEAR US-131 INSTEAD OF NEAR THE LAKE SHORE. CURRENTLY (6 AM)
THE LOWEST REPORTED VISIBILITIES ARE LOCATIONS NEAR US-131
(RQB...FFX...GRR TO LAN ) AND NOT BY THE LAKE SHORE. ALL STATIONS
NEAR THE LAKE SHORE HAVE HAD VISIBILITIES GREATER THAN 6 MILES SINCE
I CAME TO WORK AROUND MIDNIGHT. THE HRRR AND NAM ALSO SHOW THE
LOCATION OF THE HIGHEST ACCUMULATION NEAR AND NORTH OF I-96...BY
US-131 INTO THIS AFTERNOON. THE REASON FOR THIS IS THE WINDS IN
THE CLOUD LAYER INCREASING TO 40 KNOT. THOSE STRONG OF WIND ALWAYS
BLOW THE HEAVIEST SNOW SHOWERS INLAND. THERE SHOULD BE DECREASE IN
THE SNOW SHOWER ACTIVITY THIS AFTERNOON AS MID LEVEL TEMPERATURES
START TO RISE AND SHORTWAVE CAUSING THE CURRENT BUST OF ACTIVITY
MOVES EAST OF THE AREA.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 326 AM EST WED DEC 31 2014
FORECAST CONCERNS DEAL WITH LAKE EFFECT SNOW SHOWERS TODAY AND WINDS
THIS AFTERNOON.
RADAR SHOWS SHSN CONTINUING ACROSS THE WESTERN CWA AS THE CORE OF
THE COLD AIR MOVES THROUGH. H8 TEMPS NEAR -20C ARE PROVIDING GOOD
INSTABILITY OVER THE LAKE. EVEN THOUGH MOISTURE IS SHALLOW...WE/RE
SEEING SOME LIGHT SNOW. ACCUMS ARE ONLY A FEW TENTHS OF AN INCH
THOUGH DUE TO A LOW AND SHALLOW DGZ WITH LIMITED LIFT WITHIN THAT
ZONE. AS THE CORE OF THE COLD AIR MOVES EAST...THE SHSN WILL
DIMINISH LATE TODAY. WINDS WILL ALSO INCREASE AS THE NEXT COLD FRONT
DROPS SOUTH INTO THE NORTHERN GREAT LAKES. WIND PROFILES IN THE FAR
NW CWA SUGGEST WE COULD SEE WIND GUSTS IN EXCESS OF 45 KTS...SO WE
HAVE ISSUED A WIND ADVISORY FOR MASON COUNTY FROM THIS AFTERNOON
THROUGH TONIGHT.
A STRONG SHORT WAVE WILL ACCOMPANY THE COLD FRONT THURSDAY AND
THURSDAY NIGHT AS IT MOVES OVER NORTHERN LOWER MICHIGAN. SOME LIGHT
SNOW IS POSSIBLE WITH THE SYSTEM WITH BOUNDARY LAYER RH AROUND 90
PERCENT. OVERALL MOISTURE IS DEEPER WITH THIS SYSTEM BUT THE MAIN
AREA OF LIFT IS WELL BELOW THE DGZ WHICH IS PROGGED AOA 10K FT. THIS
WILL CUT DOWN ON ACCUMS QUITE A BIT. PLACED HIGHEST POPS OVER THE
NRN CWA.
.LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY)
ISSUED AT 326 AM EST WED DEC 31 2014
MY FORECAST CONFIDENCE FOR A SYSTEM MOVING THROUGH SOUTHERN LOWER
MICHIGAN SATURDAY INTO EARLY SUNDAY CONTINUES TO INCREASE. IT IS
LOOKING MORE AND MORE LIKE MOSTLY SNOW...WITH MIXED PRECIPITATION IN
THE I-69 AREA SATURDAY EVENING. BEHIND THAT MUCH COLDER AIR MOVES IN
THAT WILL REMAIN IN PLACE MOST OF NEXT WEEK. LAKE EFFECT SNOW WILL
BE ACTIVE THROUGH THE SUNDAY TO TUESDAY TIME FRAME.
THE SATURDAY STORM SYSTEM RESULTS FROM THE PHASING OF THREE SYSTEMS.
WHAT PHASES IS THE CLOSED UPPER LOW CURRENTLY OVER THE SOUTHWEST
UNITED STATES....AND A DIGGING ARCTIC SHORTWAVE AND A PACIFIC
SHORTWAVE. THE PHASING OF THESE THREE SYSTEMS HAPPENS ON SATURDAY AS
THE STORM APPROACHES OUR AREA. THERE IS STILL SOME QUESTION AS TO
THE TRACK AND HOW MUCH WARM AIR COMES WEST OF THE SYSTEM. HOWEVER...
UNLIKE THE SYSTEM ON CHRISTMAS...THIS SYSTEM HAS A LOT OF COLD AIR
TO WORK WITH SO THERE SHOULD BE MUCH LESS OF AN ISSUE WITH GETTING A
SIGNIFICANT AMOUNT OF THE STORMS PRECIPITATION IN OUR CWA TO BE SNOW
GIVEN THE TRACK IS THROUGH SOUTHEAST MICHIGAN. I STILL ALLOWED FOR
SLEET...FREEZING RAIN TO MIX IN OVER MOST AREAS NEAR AND EAST OF
GRAND RAPIDS SATURDAY AFTERNOON. THIS WILL HAVE TO BE ADJUSTED AS
THE STORM TRACK BECOMES MORE CERTAIN.
BEHIND THE SYSTEM WE TO HAVE THE ISSUE WITH SPLITTING POLAR VORTEX.
THAT WILL ASSURES A SIGNIFICANT PUSH OF MUCH COLDER AIR BEHIND THE
SYSTEM SATURDAY NIGHT. BOTH THE ECMWF AND GFS HAVE 850 TEMPS
FALLING TO NEAR -25C IN THE MONDAY-TUESDAY TIME FRAME. GIVEN THAT
AMOUNT OF COLD AIR AND A SERIES OF SHORTWAVES ON THE NORTHERN BRANCH
OF THE POLAR JET..LITTLE QUESTION IN MY MIND...LAKE EFFECT SNOW WILL
BE ON-GOING THROUGH THE MIDDLE OF NEXT WEEK.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 611 AM EST WED DEC 31 2014
FOR THE MOST PART MVFR CEILING PREVAIL AT MOST TAF SITES AT 11Z THIS
MORNING. SNOW SHOWERS HAVE BROUGHT IFR VISIBILITIES TO GRR....LAN
AND JXN OVER THE PAST FEW HOURS BUT NOT MKG...AZO OR BTL. I EXPECT
THE SNOW SHOWER ACTIVITY TO CONTINUE INTO LATE MORNING BEFORE
DECREASING SOME AS DRIER AIR MOVES IN. I WOULD ALSO EXPECT THE
I-96 TAF SITES... EXCEPT FOR MKG (TO CLOSE TO THE LAKE SHORE WITH
THE STRONG WINDS IN THE CLOUDS TODAY) WILL CONTINUE TO SEE
OCCASIONAL IFR VISIBILITIES IN SNOW SHOWERS INTO LATE MORNING OR
EARLY AFTERNOON. VFR CONDITIONS WITH STRONG WEST WINDS WILL
PREVAIL THIS AFTERNOON. ADDITIONAL LIGHT SNOW SHOWERS WILL
REDEVELOP AFTER 06Z AS ANOTHER SHORTWAVE MOVES INTO THE AREA.
&&
.MARINE...
ISSUED AT 1210 PM EST WED DEC 31 2014
KEPT THE MARINE HEADLINES UNCHANGED. ADDED FREEZING SPRAY TO THE
FORECAST BUT DID NOT ISSUE ADVISORY OR WARNING BASED ON
COORDINATION WITH SURROUNDING OFFICES.
&&
.HYDROLOGY...
ISSUED AT 326 AM EST WED DEC 31 2014
COLD TEMPS WILL CONTINUE TO AID IN ICE DEVELOPMENT ON AREA
WATERWAYS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WIND ADVISORY UNTIL 6 AM EST THURSDAY FOR MIZ037.
LM...SMALL CRAFT ADVISORY UNTIL NOON EST TODAY FOR LMZ844>849.
GALE WARNING UNTIL 6 AM EST THURSDAY FOR LMZ844>849.
&&
$$
UPDATE...OSTUNO
SYNOPSIS...OSTUNO
SHORT TERM...93
LONG TERM...WDM
AVIATION...WDM
HYDROLOGY...93
MARINE...OSTUNO
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1228 PM EST WED DEC 31 2014
.SYNOPSIS...
DRY AND COOL CONDITIONS ARE EXPECTED TODAY AND NEW YEAR`S DAY AS
HIGH PRESSURE PUSHES INTO THE AREA. A WARM FRONT WILL BRING
INCREASING CLOUDS FRIDAY WITH PERIODS OF RAIN SATURDAY. MILD
TEMPERATURES WILL FOLLOW SUNDAY AHEAD OF A STRONG COLD FRONT. THE
FRONT MAY BRING A FEW THUNDERSTORMS SUNDAY AFTERNOON AND NIGHT.
CLEARING AND COLD CONDITIONS WILL OVERSPREAD THE CAROLINAS EARLY
NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 945 AM WEDNESDAY...ARCTIC HIGH PRESSURE CENTERED OVER THE HIGH
PLAINS COVERS THE EASTERN THREE-QUARTERS OF THE NATION AND IS
FEEDING DRY CHILLY AIR SOUTHWARD INTO THE COASTAL CAROLINAS. THE
BIGGEST FORECAST CHALLENGE TODAY IS ANTICIPATING THE AMOUNT AND
OPACITY OF CIRRUS THAT WILL COVER THE SKY...PARTICULARLY ACROSS THE
NORTHERN HALF OF OUR FORECAST AREA WHERE RECENT NAM AND RUC RELATIVE
HUMIDITY FORECASTS AT AND ABOVE 300 MB SHOW A GOOD DEAL OF MOISTURE
AND POTENTIAL CLOUDINESS.
VISIBLE SATELLITE SHOWS CIRRUS ACROSS ALL BUT GEORGETOWN AND
WILLIAMSBURG COUNTY. ALTHOUGH THE SATELLITE PERSPECTIVE DOES NOT
LOOK IMPRESSIVE...A PEEK OUT THE WINDOW SHOWS THIS CIRRUS IS
SURPRISINGLY OPTICALLY DENSE AND IS BLOCKING OUT A GOOD DEAL OF
SUNLIGHT. I HAVE SHAVED OFF A DEGREE OR TWO FROM FORECAST HIGH
TEMPERATURES ACROSS SE NORTH CAROLINA AND THE DILLON-BENNETTSVILLE
REGION OF SOUTH CAROLINA...WITH LITTLE CHANGE MADE ELSEWHERE. THIS
UPPER LEVEL MOISTURE IS ADVECTING EASTWARD ALONG THE SOUTHERN EDGE
OF A 170 KNOT JET STREAK EXTENDING ACROSS THE OHIO VALLEY AND THE
NORTHERN MID-ATLANTIC STATES.
DEWPOINTS SHOULD STEADILY FALL THROUGHOUT THE DAY REACHING THE MID
TO UPPER 20S OVER THE NEXT FEW HOURS FOR MOST AREAS.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 330 AM WEDNESDAY...BEGINNING OF THE MEDIUM RANGE PERIOD
LOOKS TO BE COOL AND DRY AS SURFACE RIDGE ACROSS THE SE AND H5
ZONAL FLOW KEEP REGION DRY AND COOL. MOISTURE STARTS TO INCREASE
ACROSS THE REGION BY FRIDAY MORNING WITH CLOUDS MOVING IN FROM THE
WEST/SOUTHWEST IN RESPONSE TO DIGGING TROF AND H5 CUT OFF LOW
ACROSS THE 4 CORNERS AREA AND SW FLOW OUT OF THE GULF. START TO
INCREASE CLOUD COVER AND INTRODUCE SLIGHT CHANCE OF PCPN DURING
THE DAYLIGHT HOURS. RAMP UP POPS BY EVENING INTO CHANCE CATEGORY
AND THIS SHOULD BE THE RULE FOR THE WEEKEND AS H5 LOW ACROSS THE
SW EJECTS TO THE E THEN NE AND BECOMES AN OPEN WAVE. HIGH PRESSURE
EAST OF FL INTERACTS WITH THIS LOW AND INCREASED JET STREAMS GULF
MOISTURE ACROSS THE SE INTO THE CAROLINAS. TEMPS MODERATE TO NEAR
CLIMO BY FRIDAY.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 330 AM WEDNESDAY...WEEKEND STAYS UNSETTLED BUT MILD AS SW
FLOW ALOFT AND AT THE SURFACE TRANSPORTS MILDER AIR INTO THE
REGION AS SURFACE LOW TO OUR WEST HEADS TO THE GREAT LAKES.
COASTAL TROUGH MOVES ONSHORE BY SUNDAY BOOSTING TEMPS WELL INTO
THE 60S AND PERHAPS SOME LOWER 70S READINGS. WITH THIS CANNOT RULE
OUT A CHANCE OF A RUMBLE OR TWO OF THUNDER SUNDAY AND SUNDAY NIGHT
AS INCREASED LOW LEVEL JET INCREASES INSTABILITY ABOVE THE
SURFACE. EVEN THOUGH FORECASTING LESS THAN 1/2 INCH OF PCPN WOULD
NOT BE SURPRISED TO SEE SOME ISOLATED HIGHER AMOUNTS AS TROUGH
INTERACTS WITH ADVANCING COLD FRONT ON SUNDAY. I DO NOT EXPECT A
TOTAL WASHOUT OVER THE WEEKEND AS WE WILL SEE SOME DRY PERIODS
MIXED IN WITH THE OCCASIONAL LIGHT RAIN. THE UNSETTLED PERIOD WILL
END LATE SUNDAY EARLY MONDAY AS A COLD FRONT SWEEPS INTO THE
REGION AND DRYS OUT THE AREA. EXPECT COOLER WEATHER TO USHER BACK
IN TO THE AREA NEXT WEEK AND THE POSSIBILITY OF ANOTHER SHOT OF
RAIN TOWARDS THE END OF THE PERIOD AS GFS DEVELOPS A LOW OFF THE
SE COAST ALONG A COASTAL TROUGH. SO BRIEF PERIOD OF MILD
TEMPERATURES OVER THE WEEKEND WILL COME TO AN END MONDAY. H5
PATTERNS SHOWS A FULL LATITUDE TROUGH DEVELOPING ACROSS THE
CENTRAL PORTION OF THE U.S. AND MOVING EASTWARD BY THE END OF THE
PERIOD.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AS OF 18Z...VFR THIS TAF VALID PERIOD. SCT HIGH CLOUDS TODAY WITH
SCT MID/BKN HIGH CLOUDS TOWARDS THE LATTER PART OF THE PERIOD. LIGHT
N WINDS WILL BECOME CALM EARLY THIS EVENING. DESPITE EXCELLENT
RADIATIONAL COOLING CONDITIONS NOT EXPECTING ANY FOG ISSUES TONIGHT
WITH A DRY AIRMASS IN PLACE. AFTER SUNRISE LGT/VRBL WINDS EXPECTED.
EXTENDED OUTLOOK...VFR INTO FRI. CHANCE OF RAIN AND MVFR/TEMPO IFR
CONDITIONS FRI NIGHT THROUGH SUN. BECOMING VFR LATE SUN. VFR MON.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 945 AM WEDNESDAY...ARCTIC HIGH PRESSURE OVER THE HIGH PLAINS
CONTROLS THE WEATHER OVER THE EASTERN THREE-QUARTERS OF THE NATION.
NORTHERLY WINDS ON THE EASTERN PERIPHERY OF THIS HIGH WILL CONTINUE
THROUGH TONIGHT. WIND SPEEDS ARE AS STRONG AS THEY`LL BE THE REST OF
THE DAY RIGHT NOW...AND GRADUALLY DIMINISHING SPEEDS ARE EXPECTED
THIS AFTERNOON INTO TONIGHT.
SEAS ARE CURRENTLY 4 FEET AT THE FRYING PAN SHOALS BUOY AND 1-4 FEET
AT VARIOUS LOCATIONS WITHIN THE NEARSHORE WATERS DEPENDING ON THE
DEGREE OF SHOALING/BLOCKING DUE TO THE SHALLOW WATERS ON FRYING PAN
SHOALS. THE BULK OF THE WAVE ENERGY IS DUE TO A 8-9 SECOND NE SWELL
BEING PRODUCED BY THE NORTHERLY WINDS BEHIND LOW PRESSURE IN THE
CENTRAL ATLANTIC. THE LOCAL SWAN MODEL ACTUALLY SHOWS THIS QUITE
WELL...AND THE MAJOR CHANGES I HAVE MADE TO FORECAST SEA HEIGHTS
OVER THE NEXT 24 HOURS ARE THE RESULT OF INCORPORATING THE SWAN
MODEL INTO OUR FORECAST. THE LARGEST ADJUSTMENTS IN THE FORECAST
WERE ALONG THE BRUNSWICK AND UPPER HORRY COUNTY COASTLINE WHERE SEA
HEIGHT FORECASTS HAVE BEEN SLASHED BY ABOUT HALF...VERIFIED BY
CURRENT DATA FROM THE SUNSET BEACH NEARSHORE BUOY.
SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 330 AM WEDNESDAY...PREVIOUS DISCUSSION LOOKS GOOD AND SEE
NO REASON TO CHANGE AT THIS POINT...HIGH PRESSURE WILL CONTINUES
TO SLOWLY BUILD IN ACROSS THE WATERS WEDNESDAY INTO THURSDAY.
NORTHERLY WINDS 10 TO 15 KTS WILL SUBSIDE TO AROUND 10 KTS LATE
OVERNIGHT WEDNESDAY INTO THURSDAY BECOMING NORTHEASTERLY FOR THE
REMAINDER OF THE PERIOD. SEAS 2 TO 3 FT..WITH 4 FOOTERS POSSIBLE
IN THE EXTREME OUTER WATERS...BECOMING GENERALLY 1 TO 3 FT INTO
THURSDAY.
LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 330 AM WEDNESDAY...WINDS AND SEAS START TO BUILD OVER THE
COASTAL WATERS INTO AND THE THROUGH THE WEEKEND AS GRADIENT
STARTS TO INCREASE IN RESPONSE TO A COASTAL TROUGH AND ADVANCING
COLD FRONT TO OUR WEST. SEAS WILL BUILD TO AROUND 5 TO 6 FEET ON
SUNDAY ACROSS THE OUTER WATERS WITH 2-4 FEET INLAND...WILL NEED TO
MONITOR FOR POSSIBLE SCA AS SW WINDS OF 15-20 KT AND SOME SLIGHT
CHOP TO THE SEAS. WINDS SUNDAY AFTERNOON INTO EVENING START TO
VEER TO THE W THEN NW AND ABATE A BIT BEFORE KICKING UP AGAIN
AFTER FROPA SUNDAY NIGHT EARLY MONDAY. AGAIN THE THREAT OF SOME
CONVECTION IS BEST ON SUNDAY AND SUNDAY NIGHT ACROSS THE WATERS.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...TRA
SHORT TERM...MAC
LONG TERM...MAC
AVIATION...MRR
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
316 PM CST WED DEC 31 2014
.DISCUSSION...
CHALLENGING FORECAST TODAY AS THE INFLUENCE OF A COMPLEX WESTERN
U.S. TROUGH AFFECTS MUCH OF TEXAS BEGINNING TONIGHT. WITH ARCTIC
AIR IN PLACE ACROSS THE REGION...FREEZING AND FROZEN PRECIPITATION
WILL BE A SIGNIFICANT THREAT TONIGHT AND THURSDAY MORNING...
ESPECIALLY ALONG AND WEST OF INTERSTATE 35.
WE WILL CONTINUE WITH THE WINTER STORM WARNING FOR 8 COUNTIES IN
THE WESTERN SECTIONS OF NORTH TEXAS WHERE UP TO ONE QUARTER INCH
OF FREEZING RAIN MAY FALL TONIGHT AND EARLY THURSDAY. TEMPERATURES
IN THE WARNING AREA ARE FORECAST TO BE IN THE MID TO UPPER 20S
DURING THE ONSET OF HEAVIER BANDED PRECIPITATION AFTER MIDNIGHT
TONIGHT. PROGRESSIVELY LESSER IMPACTS ARE EXPECTED FURTHER EAST
FROM THE WARNING AREA...WITH TEMPERATURES NEAR OR JUST BELOW
FREEZING FORECAST DURING THE PRECIPITATION. THE EXACT IMPACTS IN
ANY GIVEN LOCATION IN THE ADVISORY AND WARNING AREAS THROUGH EARLY
THURSDAY WILL BE DETERMINED BY TEMPERATURES DURING THE ONSET OF
HEAVIER PRECIPITATION AND THE LOCATION OF ANY SLEET SHOWERS THAT
SPREAD EASTWARD OVERNIGHT.
WITH REGARD TO THE KEY WEATHER FEATURES...THE STRONG UPPER TROUGH
CURRENTLY DEVELOPING INTO WESTERN ARIZONA WILL EJECT INTO THE
PLAINS WITH TWO DISTINCTIVE WAVES. THE FIRST WAVE OF ENERGY IS
FORECAST TO MOVE ACROSS NORTHERN NEW MEXICO AND EASTERN COLORADO
ON THURSDAY AND WILL BE RESPONSIBLE FOR THE WINTER WEATHER EVENT
TONIGHT. PLENTIFUL PACIFIC MOISTURE...STRONG LOW LEVEL WARM AIR
ADVECTION...AND SOME MID LEVEL FRONTOGENESIS WILL LEAD TO THE
DEVELOPMENT OF WIDESPREAD PRECIPITATION FROM WEST TO EAST AFTER
MIDNIGHT. SOME CONVECTIVE BANDS /SHOWERS/ ARE FORECAST TO DEVELOP
IN THE AXIS OF FRONTOGENESIS TONIGHT WHICH IS FORECAST TO BE
CENTERED FROM THE EASTLAND AND BRECKENRIDGE AREAS EASTWARD INTO
THE DFW METROPLEX AFTER MIDNIGHT. WINTER WEATHER IMPACTS WILL BE
ENHANCED LOCALLY NEAR ANY OF THE HEAVIER SLEET SHOWERS THAT
DEVELOP IN AREAS WITH SURFACE TEMPERATURES NEAR OR BELOW FREEZING.
EXPECT PRECIPITATION TO CONTINUE IN MOST AREAS DURING FOR MUCH OF
THE DAY THURSDAY AND WILL GRADUALLY TRANSITION TO ALL LIQUID RAIN
DURING THE AFTERNOON HOURS AS TEMPERATURES SLOWLY RISE TO ABOVE
FREEZING. THE NUMERICAL MODEL GUIDANCE SUGGESTS THAT THE
MODIFICATION OF THE ARCTIC AIRMASS MAY BE ACCELERATED IN TWO WAYS.
FIRST...THE RELATIVELY WARM RAINDROPS FALLING THROUGH THE
INCREASINGLY WARM AIR ABOVE THE FRONTAL INVERSION WILL EFFECTIVELY
TRANSFER HEAT TO THE NEAR SURFACE AIR. SECOND...THE RELEASE OF
LATENT HEATING BY THE PRECIPITATION PRODUCTION PROCESS IN THE
ABSENCE OF LOW LEVEL COLD ADVECTION COULD ALSO RESULT IN SLOWLY
RISING TEMPERATURES. BY LATE THURSDAY AFTERNOON...EXPECT
TEMPERATURES TO BE AT 32 OR HIGHER IN ALL AREAS...WITH THE COLDEST
TEMPERATURES IN THE FAR NORTHWEST ZONES.
THERE MAY BE A BRIEF 6-12 HOUR LULL IN THE RAIN THURSDAY EVENING
AND THURSDAY NIGHT AS THE FIRST WAVE OF ENERGY FROM THE SOUTHWEST
U.S. SYSTEM MOVES ACROSS KANSAS THURSDAY NIGHT. HOWEVER...THE
PRIMARY SHORTWAVE / SECOND WAVE OF ENERGY / IS FORECAST TO EJECT
EASTWARD INTO NEW MEXICO AND WEST TEXAS BY LATE FRIDAY. WIDESPREAD
RAIN WILL REDEVELOP IN ALL AREAS BY LATE THURSDAY NIGHT OR EARLY
FRIDAY AND CONTINUE INTO FRIDAY NIGHT. THE RAINS AND ISOLATED
THUNDERSTORMS WILL END FROM WEST TO EAST ON SATURDAY AFTERNOON AS
THE SHORTWAVE EJECTS QUICKLY ACROSS OKLAHOMA.
A THIRD SYSTEM WILL MOVE ACROSS THE AREA ON SUNDAY...BUT THIS
SYSTEM SHOULD BE WEAKER AND LACK SIGNIFICANT MOISTURE TO PRODUCE
PRECIPITATION. WILL KEEP THE FORECAST FOR SUNDAY INTO THE MIDDLE
OF NEXT WEEK DRY...WITH TEMPERATURES CONTINUING TO AVERAGE BELOW
NORMAL.
09/GP
&&
.AVIATION...
/ISSUED 1212 PM CST WED DEC 31 2014/
/18Z TAF ISSUANCE/
PRIMARY CONCERN WITH THIS TAF ISSUANCE IS THE OCCURRENCE...TIMING
AND LOCATION OF FREEZING RAIN AT THE METROPLEX AIRPORT SITES THROUGH
THURSDAY MORNING. BY 12Z THURS...THERE WILL BE A ROUGH DEMARCATION
ACROSS THE DFW METROPLEX BETWEEN SITES THAT RECEIVE NO ICING AT
ALL...AND THOSE THAT HAVE VARYING DEGREES OF ICE IMPACT ON PAVED
AREAS AND ELEVATED SURFACES. WACO TAF SITE WILL ALSO BE ON THE
BORDERLINE AS FAR AS IMPACTS...BUT PROBABLY STAY LIQUID.
ARCTIC AIRMASS WILL REMAIN IN PLACE ACROSS NORTH TEXAS THROUGH
FRIDAY. WHILE SURFACE TEMPERATURES AT ALL SITES ARE NOW RUNNING IN
THE MID 30S...BELIEVE THESE READINGS WILL SLIP BACK TOWARD
FREEZING BEGINNING THIS EVENING...AIDED BY SOME WEAK COLD
ADVECTION AND PRECIPITATION-INDUCED COOLING. SPOTTY LIGHT RAIN
WILL LIKELY BEGIN ACROSS NORTH TEXAS AFTER 02Z THIS
EVENING...BECOMING MORE WIDESPREAD AFTER 06Z AND CONTINUING
THROUGH AT LEAST 21Z THURSDAY. ONSET AT WACO WILL BE DELAYED
SOMEWHAT...BUT EXPECT CATEGORICAL RAIN THERE BY 08Z.
BASED ON LATEST HRRR AND NAM MODELS...CURRENT THINKING IS THAT
SUB-FREEZING AIR TEMPS WILL EXIST FOR SEVERAL HOURS IN THE WESTERN
PORTIONS OF THE DFW METROPLEX AFTER 08Z...CREATING SOME ICE IMPACTS
AT KAFW AND KFTW THRU AT LEAST 15Z. KDFW...KDAL AND KGKY WILL BE
BORDERLINE...BUT BELIEVE THERE WILL BE A PERIOD AFTER 09Z WHEN
-FZRA WILL OCCUR...AT LEAST ON ELEVATED SURFACES. NOT CONFIDENT
ENOUGH OF ANY SUSTAINED FREEZING PRECIPITATION AT WACO TO MENTION
IN TAF AT PRESENT. RAINFALL WILL PICK UP IN INTENSITY AFTER
12Z...AND EXPECT A SLIGHT REBOUND IN TEMPERATURES TO LOWER/MIDDLE
30S AFTER THAT TIME. ANY ICE THAT DOES DEVELOP AT METROPLEX TAF
SITES SHOULD DISSIPATE DUE TO COMBINATION OF HEAVIER RAIN AND
SLIGHTLY WARMER AIR AND PRECIPITATION TEMPERATURES.
BRADSHAW
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 30 36 36 41 40 / 60 80 70 80 70
WACO, TX 32 38 38 42 39 / 70 80 80 80 70
PARIS, TX 32 37 36 42 40 / 40 90 80 80 80
DENTON, TX 27 35 35 40 38 / 60 80 70 80 70
MCKINNEY, TX 27 35 35 41 39 / 50 80 70 80 70
DALLAS, TX 31 37 37 41 40 / 60 80 70 80 70
TERRELL, TX 33 37 37 41 40 / 50 80 80 80 70
CORSICANA, TX 34 39 39 42 41 / 60 80 80 80 80
TEMPLE, TX 32 38 38 41 39 / 70 80 80 80 70
MINERAL WELLS, TX 26 33 33 39 36 / 70 80 70 80 70
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL 3 PM CST THURSDAY FOR TXZ100-101-115-
116-129-130-141-142.
WINTER WEATHER ADVISORY UNTIL 3 PM CST THURSDAY FOR TXZ091>094-
102>104-117>120-131>134-143>145-156>159.
&&
$$
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
1212 PM CST WED DEC 31 2014
.AVIATION...
/18Z TAF ISSUANCE/
PRIMARY CONCERN WITH THIS TAF ISSUANCE IS THE OCCURRENCE...TIMING
AND LOCATION OF FREEZING RAIN AT THE METROPLEX AIRPORT SITES THROUGH
THURSDAY MORNING. BY 12Z THURS...THERE WILL BE A ROUGH DEMARCATION
ACROSS THE DFW METROPLEX BETWEEN SITES THAT RECEIVE NO ICING AT
ALL...AND THOSE THAT HAVE VARYING DEGREES OF ICE IMPACT ON PAVED
AREAS AND ELEVATED SURFACES. WACO TAF SITE WILL ALSO BE ON THE
BORDERLINE AS FAR AS IMPACTS...BUT PROBABLY STAY LIQUID.
ARCTIC AIRMASS WILL REMAIN IN PLACE ACROSS NORTH TEXAS THROUGH
FRIDAY. WHILE SURFACE TEMPERATURES AT ALL SITES ARE NOW RUNNING IN
THE MID 30S...BELIEVE THESE READINGS WILL SLIP BACK TOWARD
FREEZING BEGINNING THIS EVENING...AIDED BY SOME WEAK COLD
ADVECTION AND PRECIPITATION-INDUCED COOLING. SPOTTY LIGHT RAIN
WILL LIKELY BEGIN ACROSS NORTH TEXAS AFTER 02Z THIS
EVENING...BECOMING MORE WIDESPREAD AFTER 06Z AND CONTINUING
THROUGH AT LEAST 21Z THURSDAY. ONSET AT WACO WILL BE DELAYED
SOMEWHAT...BUT EXPECT CATEGORICAL RAIN THERE BY 08Z.
BASED ON LATEST HRRR AND NAM MODELS...CURRENT THINKING IS THAT
SUB-FREEZING AIR TEMPS WILL EXIST FOR SEVERAL HOURS IN THE WESTERN
PORTIONS OF THE DFW METROPLEX AFTER 08Z...CREATING SOME ICE IMPACTS
AT KAFW AND KFTW THRU AT LEAST 15Z. KDFW...KDAL AND KGKY WILL BE
BORDERLINE...BUT BELIEVE THERE WILL BE A PERIOD AFTER 09Z WHEN
-FZRA WILL OCCUR...AT LEAST ON ELEVATED SURFACES. NOT CONFIDENT
ENOUGH OF ANY SUSTAINED FREEZING PRECIPITATION AT WACO TO MENTION
IN TAF AT PRESENT. RAINFALL WILL PICK UP IN INTENSITY AFTER
12Z...AND EXPECT A SLIGHT REBOUND IN TEMPERATURES TO LOWER/MIDDLE
30S AFTER THAT TIME. ANY ICE THAT DOES DEVELOP AT METROPLEX TAF
SITES SHOULD DISSIPATE DUE TO COMBINATION OF HEAVIER RAIN AND
SLIGHTLY WARMER AIR AND PRECIPITATION TEMPERATURES.
BRADSHAW
&&
.UPDATE...
...WINTER WEATHER ADVISORY EXPANDED EASTWARD TO INCLUDE DALLAS AND WACO...
CURRENT OBSERVED TRENDS AND UPDATED MODEL GUIDANCE CONTINUE TO
COME IN COLDER THAN PREVIOUSLY EXPECTED...SO HAVE NUDGED DAYTIME
HIGHS AND OVERNIGHT LOWS DOWN A FEW DEGREES FOR THE NEXT 24 HOURS.
THE UPPER LEVEL DISTURBANCE THAT WILL PROVIDE THE NECESSARY LIFT
FOR PRECIPITATION TONIGHT AND TOMORROW FOR NORTH AND CENTRAL TEXAS IS
CENTERED OVER SOUTHERN CALIFORNIA/WESTERN ARIZONA AS OF 9 AM.
MODEL GUIDANCE APPEARS TO BE IN GOOD AGREEMENT THAT THIS ENERGY
WILL AFFECT THE REGION AS EARLY AS TONIGHT. AS A RESULT OF THE
TEMPERATURE TRENDS AND UPPER LEVEL SUPPORT EXPECTED TO BE IN PLACE...A
LARGER AREA OF NORTH AND CENTRAL TEXAS IS EXPECTED TO RECEIVE A
MIXED BAG OF WINTER PRECIPITATION THROUGH MIDDAY TOMORROW. THIS
TEMPERATURE TREND WARRANTED THE EASTWARD EXPANSION OF THE WINTER
WEATHER ADVISORY AS WELL.
AJS
&&
.PREV DISCUSSION... /ISSUED 420 AM CST WED DEC 31 2014/
LIGHT BANDS OF FREEZING DRIZZLE...FREEZING RAIN...SLEET AND EVEN
SOME LIGHT SNOW SET UP OVERNIGHT ACROSS THE NORTH/NORTHWEST
COUNTIES OF NORTH TEXAS. SOME LIGHT ACCUMULATIONS OF MAINLY SNOW WERE
REPORTED ACROSS PORTIONS OF JACK COUNTY AND WISE COUNTY. MOIST
ISENTROPIC LIFT OVER THE ARCTIC AIR MASS WAS RESPONSIBLE FOR THE
PRECIP. THE FREEZING DRIZZLE AND SLEET WAS EXPECTED BUT WAS A BIT
SURPRISED TO SEE THE LITTLE BANDS OF SNOW SINCE THE DENDRITIC
GROWTH ZONE WAS NO WHERE NEAR SATURATED. MODELS INDICATE THAT THE
ISENTROPIC LIFT WILL WEAKEN IN THE NORTHWEST ZONES THROUGH SUNRISE
SO PRECIP SHOULD CONTINUE TO WEAKEN/DISSIPATE.
MODELS ARE IN FAIRLY GOOD AGREEMENT THAT ISENTROPIC LIFT WILL BE ON
THE INCREASE ACROSS THE SOUTHWEST ZONES OF NORTH TEXAS DURING THE
DAY TODAY AND WE WOULD NOT BE SURPRISED TO SEE MORE MIXED WINTER
PRECIPITATION DEVELOP BEFORE SUNSET.
LARGE SCALE UPWARD FORCING WILL BE ON THE INCREASE TONIGHT AS THE
STRONG UPPER LOW CURRENTLY OVER SOUTHERN CALIFORNIA MOVES EAST
ACROSS ARIZONA. ALTHOUGH THE BEST LIFT WILL STILL REMAIN WEST OF
THE REGION UNTIL THE UPPER LOW GETS CLOSER...ALL 00Z MODEL RUNS
INDICATE THAT A PIECE OF ENERGY WILL ROUND THE BASE OF THE UPPER
LOW AND MOVE EAST NORTHEAST ACROSS THE REGION. FOR THIS REASON WE
HAVE DECIDED TO EXPAND THE ADVISORY THAT IS CURRENTLY IN EFFECT TO
INCLUDE ONE MORE ROW OF COUNTIES TO THE EAST AND ALSO GRAYSON...FANNIN
AND COLLIN COUNTIES. WE HAVE ALSO CHANGED THE FREEZING RAIN ADVISORY TO A
WINTER WEATHER ADVISORY SINCE THE PRECIP TONIGHT MAY BE MORE OF A
MIX OF FREEZING RAIN AND SLEET. IT DOES APPEAR THAT FREEZING RAIN
WILL BECOME THE DOMINANT WEATHER TYPE AFTER SUNRISE THURSDAY ONCE
THE WARM LAYER ABOVE THE ARCTIC AIR DEEPENS. OUR PRIMARY CONCERN
IS THAT THE NORTHWEST ZONES WHICH ARE CURRENTLY IN THE MIDDLE 20S
WILL NOT WARM UP MUCH TODAY AND THAT THERE WILL BE A PERIOD OF
FAIRLY SIGNIFICANT ICE AND SOME SLEET THURSDAY MORNING. FOR THIS
REASON WE HAVE DECIDED TO UPGRADE THE CURRENT ADVISORY TO A WINTER
STORM WARNING. THE WARNING AREA WILL INCLUDE LOCATIONS ALONG AND
WEST OF A LINE FROM JACKSBORO TO STEPHENVILLE TO GOLDTHWAITE.
ACCUMULATIONS OF ICE AND SLEET IN THE REGION COULD TOTAL ONE
QUARTER INCH. AM GROWING MORE CONCERNED THAT ALL MODELS ARE
TRENDING WETTER AND COLDER SO FUTURE UPGRADES AND ADJUSTMENTS ARE
VERY POSSIBLE.
PRECIPITATION SHOULD TRANSITION INTO A COLD RAIN FOR NEARLY ALL OF
NORTH TEXAS THURSDAY AFTERNOON. SOME FREEZING RAIN MAY HOLD ON IN
THE NORTHWEST ZONES BUT SURFACE TEMPS SHOULD WARM CLOSER TO
FREEZING. RAIN WILL CONTINUE ACROSS ALL OF NORTH TEXAS THURSDAY
NIGHT THROUGH FRIDAY AS THE UPPER LOW APPROACHES. FOR NOW WE HAVE
KEPT ALL TEMPS THURSDAY NIGHT THROUGH FRIDAY NIGHT ABOVE FREEZING
WITH ONLY RAIN EXPECTED BUT WE WILL HAVE TO WATCH THE THURSDAY
NIGHT TIME PERIOD AS A FEW SPOTS MAY BE VERY CLOSE TO FREEZING.
RAIN CHANCES WILL END FROM WEST TO EAST SATURDAY AS THE UPPER LOW
MOVES NORTHEAST INTO THE CENTRAL PLAINS.
SATURDAY NIGHT THROUGH TUESDAY WILL BE DRY WITH NORTHWEST FLOW
ALOFT AND LIMITED SURFACE MOISTURE.
79
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 37 30 40 35 40 / 10 50 70 70 70
WACO, TX 40 31 40 36 42 / 20 40 80 70 70
PARIS, TX 38 30 37 34 42 / 10 20 80 80 70
DENTON, TX 35 29 37 33 40 / 10 50 70 60 70
MCKINNEY, TX 38 29 38 33 39 / 10 20 80 70 70
DALLAS, TX 38 32 42 36 41 / 10 40 80 70 70
TERRELL, TX 41 33 38 36 40 / 10 20 80 70 70
CORSICANA, TX 41 32 39 37 41 / 10 30 80 70 70
TEMPLE, TX 41 33 40 36 41 / 20 40 70 70 70
MINERAL WELLS, TX 32 28 37 33 38 / 20 50 70 60 70
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL 3 PM CST THURSDAY FOR TXZ100-101-115-
116-129-130-141-142.
WINTER WEATHER ADVISORY UNTIL 3 PM CST THURSDAY FOR TXZ091>094-
102>104-117>120-131>134-143>145-156>159.
&&
$$
66/