Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 12/06/15
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
1225 PM EST FRI DEC 4 2015
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO INFLUENCE OUR WEATHER THROUGH THE
WEEKEND BEFORE MOVING OFFSHORE LATE SUNDAY INTO MONDAY. A LOW
PRESSURE SYSTEM IS FORECAST TO DEVELOP ALONG THE MID ATLANTIC COAST
ON MONDAY, THEN TRACK NORTHEAST TUESDAY AND WEDNESDAY WHILE
REMAINING OFFSHORE. HIGH PRESSURE WILL NOSE DOWN FROM THE NORTH FOR
WEDNESDAY AND THURSDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A VERY NICE DAY WITH SURFACE HIGH PRESSURE PUSHING IN FROM THE
WEST. AFTERNOON TEMPS WILL BE ABOUT NORMAL WITH FULL SUN. WELL,
WE WENT WITH THE HRRR EARLIER THIS MORNING AND ADDED A FEW MORE
CLOUDS BACK INTO THE GRIDS ACROSS THE NORTHERN AND WESTERN ZONES.
FOR THIS UPDATE, WE`RE GOING TO REMOVE THEM. THE SUBSIDENCE HAS
ARRIVED.
PREVIOUS DISCUSSION
WITH THE FORECAST ON TRACK, THERE WAS MINIMAL GRID WORK WITH THIS
UPDATE. I DID CHANGE SOME SPURIOUS TEMP/DEWPOINT GRIDS WHICH ALSO
AFFECTED A COUPLE OF OTHER RELATED GRIDS AS WELL.
SOME OF THE SKY GRIDS WERE ADJUSTED. THE VIS SAT PIC DOES SHOW
STRATOCU DISSIPATING, AS FORECAST, ACROSS THE LEHIGH VALLEY, SE
PA, AND WESTERN NJ. BUT WE FEEL THE CLOUDS WILL HANG ON FURTHER
INTO THE DAY ACROSS THE POCONOS AND NW NJ.
PREVIOUS DISCUSSION...
UPPER LEVEL SHORT WAVE RIDGE OVER THE NORTHERN PLAINS NOW WILL SLIDE
EAST INTO THE GREAT LAKES REGION BY THE END OF THE DAY. AT THE SAME
TIME, THE SURFACE HIGH, CURRENTLY CENTERED OVER KENTUCKY AND
INDIANA, WILL STRENGTHEN.
WHAT THIS MEANS FOR OUR REGION IS TRANQUIL WEATHER. THE MID LEVEL
CLOUDS OVER THE WESTERN PORTIONS OF THE REGION NOW, COULD PERSIST
THROUGH EARLY THIS AFTERNOON, AS MID LEVEL NORTHWESTERLY FLOW
CONTINUES. HOWEVER, BY MID AFTERNOON, SUBSIDENCE SHOULD LEAD TO
CLEARING SKIES. HIGHS SHOULD RANGE FROM THE LOWER 40S (GENERALLY
OVER THE POCONOS WHERE THE CLOUDS WILL BE SLOWER TO DISSIPATE) TO
THE LOWER 50S OVER THE COASTAL PLAINS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SATURDAY/...
HIGH SLIDES A BIT CLOSER TO THE REGION TONIGHT, LEADING TO CLEARING
SKIES AND SUBSIDENCE. AS SUCH, EXPECT PRIME RADIATIONAL COOLING
CONDITIONS FOR TONIGHT. THUS, WENT ON THE LOWER SIDE OF GUIDANCE,
WITH LOWS RANGING FROM THE MID 20S TO MID 30S.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
STRONG HIGH PRESSURE WILL CONTINUE TO INFLUENCE OUR WEATHER THROUGH
THIS WEEKEND. THE HIGH WILL CREST OVER THE AREA ON SUNDAY AND THEN
START TO PUSH TO THE EAST LATE SUNDAY, FINALLY MOVING FULLY OFFSHORE
BY EARLY MONDAY. THE WEATHER SHOULD REMAIN DRY AND SKIES WILL REMAIN
CLOUDLESS FOR THE MOST PART AS SUBSIDENCE INCREASES ACROSS THE AREA
UNDER THE RIDGE.
THE NEXT PART OF THE EXTENDED IS STILL A BIT UNCERTAIN BUT THE
MODELS ARE STARTING TO COME TOGETHER ON A MORE OFFSHORE SCENARIO FOR
THE POTENTIAL COASTAL LOW. THERE IS STILL A GOOD DEAL OF DIFFERENCE
IN THE TIMING AND STRENGTH OF THE LOW AS WELL AS JUST WHERE IT MAY
FORM OFFSHORE. THE 00Z GFS IS MUCH CLOSER TO THE COAST AND FORMS THE
LOW FURTHER TO THE SOUTH AND CLOSER TO THE COAST THAN THE 00Z ECMWF
AND AS A RESULT SHOWS MORE OF AN IMPACT ACROSS OUR AREA.
EVEN THOUGH THE GUIDANCE APPEARS TO BE TRENDING TO THE EAST WITH THE
LOW, IT DOES NOT MEAN THAT WE WILL BE OUT OF THE WOODS. THERE WILL
REMAIN A RISK FOR SOME HEAVY RAINS AND GUSTY WINDS, WHICH WOULD BE
MORE LIKELY ACROSS OUR SOUTHERN ZONES AND ALONG THE COASTAL AREAS.
ANY SHIFT TO THE WEST WOULD CERTAINLY INCREASE THE CHANCES INLAND.
WITH A POTENTIALLY STRONG NORTHEASTERLY FLOW, WE WOULD ALSO NEED TO
MONITOR ANY COASTAL CONCERNS.
SHOWERS ARE EXPECTED TO START MOVING INTO THE AREA LATER MONDAY,
MAINLY ONLY INTO OUR SOUTHERN ZONES, WITH A FEW SHOWERS POSSIBLE BY
LATE AFTERNOON. FOR THE MOST PART, THE SHOWERS WILL CONFINED CLOSER
TO THE COAST WITH DECREASING CHANCES AS YOU MOVE FURTHER INLAND.
HOWEVER, THIS IS HIGHLY DEPENDENT ON JUST HOW CLOSE THE LOW REMAINS
TO THE COAST AND HOW MUCH IT INTENSIFIES AS IT MOVES TO THE NORTH
AND EAST. OVERALL, EXPECT SHOWERS TO START TO DECREASE ACROSS THE
REGION LATE TUESDAY INTO WEDNESDAY WITH WEDNESDAY EXPECTED TO BE A
MOSTLY DRY DAY.
ONCE THE LOW PUSHES FURTHER EAST, WE SHOULD SEE A (BRIEF) RETURN TO
HIGH PRESSURE. BOTH THE GFS AND THE ECMWF SHOW HIGH PRESSURE NOSING
IN FROM THE NORTH WITH A MID LEVEL WAVE CROSSING THE AREA WEDNESDAY
INTO THURSDAY. IT`S AT THIS POINT WE START TO SEE SOME CONSIDERABLE
DIFFERENCES IN THE MODELS. THE GFS KEEPS HIGH PRESSURE OVER US AS WE
HEAD INTO THE WEEKEND WHILE THE ECMWF TRACKS A DISTURBANCE ACROSS THE
REGION LATE THURSDAY INTO FRIDAY. BOTH MODELS SHOW THAT A MID LEVEL
LOW WILL TRACK TOWARDS THE REGION BUT THE LOCATION OF THE LOW
DIFFERS WHICH LEADS TO THE VARYING SOLUTIONS. PLENTY OF TIME TO SEE
HOW THESE FEATURES MAY UNFOLD.
&&
.AVIATION /17Z FRIDAY THROUGH TUESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY, AND SURROUNDING AREAS.
VFR CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD. A CLOUD DECK
AROUND 3000 TO 4000 FT AGL COULD PERSIST THROUGH 18Z, BUT AFTER
THAT, FEW, IF ANY, CLOUDS ARE EXPECTED.
WIND DIRECTION MAY VARY BETWEEN WESTERLY AND NORTHWESTERLY THROUGH
THE TAF PERIOD, BUT WIND SPEEDS WILL GENERALLY BE NEAR OR BELOW
10KT, THOUGH A FEW GUSTS TO 15 KT ARE POSSIBLE BETWEEN 15 AND 21Z.
OUTLOOK...
SATURDAY THROUGH SUNDAY...MAINLY VFR CONDITIONS EXPECTED. NORTHWEST
WINDS AROUND 5 TO 10 KNOTS, BECOMING WEST TO SOUTHWEST ON SUNDAY.
MONDAY...MAINLY VFR CONDITIONS EXPECTED. NORTHWEST WINDS EARLY,
BECOMING NORTH TO NORTHEAST THROUGH THE DAY. WIND SPEEDS AROUND 5 TO
10 KNOTS.
TUESDAY...NORTHEAST WINDS EXPECTED WITH 20 KT GUSTS POSSIBLE,
ESPECIALLY CLOSER TO THE COAST. SUB-VFR CONDITIONS POSSIBLE IN
RAIN AS A COASTAL SYSTEM PASSES OFF THE MID ATLANTIC COAST.
&&
.MARINE...
WINDS AND SEAS SHOULD STAY BELOW SMALL CRAFT ADVISORY CONDITIONS
TODAY AND TONIGHT. A FEW GUSTS ABOVE 20 KT WILL BE POSSIBLE
THROUGH SUNRISE, BUT WINDS WILL CONTINUE TO SLOWLY SUBSIDE THROUGH
THE MORNING HOURS.
OUTLOOK...
SATURDAY THROUGH SUNDAY...EXPECT WINDS AND SEAS TO REMAIN BELOW
SMALL CRAFT ADVISORY CRITERIA THROUGH SUNDAY.
MONDAY...A NORTH TO NORTHEAST FLOW WILL DEVELOP ACROSS THE REGION
AND WINDS WILL GRADUALLY INCREASE, WITH POTENTIAL GUSTS AROUND 25
KNOTS LATE MONDAY NIGHT INTO EARLY TUESDAY. SEAS WILL ALSO START TO
BUILD BUT SHOULD REMAIN BELOW 5 FEET ON MONDAY.
TUESDAY...NORTHEAST WINDS WILL INCREASE AND GUSTS WILL EXCEED 25
KNOTS ON TUESDAY AS LOW PRESSURE IS FORECAST TO ORGANIZE TO THE
SOUTH OF OUR WATERS. SEAS WILL RISE IN THE EASTERLY FLOW AND ARE
EXPECTED TO START REACHING 5 FEET LATER ON TUESDAY.
AT THIS TIME, A SMALL CRAFT ADVISORY LOOKS LIKE IT WILL LIKELY BE
NEEDED. HOWEVER, UNCERTAINTY WITH THE TIMING, STRENGTH, AND
POSITION OF THE LOW WILL HAVE A DIRECT EFFECT ON OUR AREA WATERS.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...MEOLA
NEAR TERM...JOHNSON/KRUZDLO
SHORT TERM...JOHNSON
LONG TERM...MEOLA
AVIATION...JOHNSON/NIERENBERG/MEOLA
MARINE...JOHNSON/NIERENBERG/MEOLA
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
915 PM EST SAT DEC 5 2015
.DISCUSSION...
...ROUGH SURF AND HAZARDOUS BOATING CONDITIONS WILL CONTINUE THROUGH
SUNDAY...
CURRENT-TONIGHT...915MHZ CAPE WIND PROFILERS SHOW ENE WINDS 20-30
KNOTS THROUGH ABOUT 6.0KFT. THIS BRISK FLOW HAS BEEN PUSHING
ISOLATED SHOWERS INTO THE COAST FROM BREVARD COUNTY NORTH. SATELLITE
HAS BEEN SHOWING MORE BREAKS IN THE CLOUDS AND THE 18Z GFS INDICATES
DRYING ACROSS THE NORTH HALF TONIGHT. WILL RETAIN A 20 PERCENT
CHANCE OF SHOWERS BOTH AT THE COAST AND INLAND DUE TO THE QUITE
STRONG LOW LEVEL ONSHORE FLOW.
THE HIGHEST MOISTURE IS OVER THE SOUTH...WHICH IS CLOSEST TO STALLED
OUT FRONT. SHOWERS HAVE BEEN MUCH MORE PERSISTENT FROM ST LUCIE TO
MARTIN COUNTY. THE GFS SHOWED LITTLE CHANGE IN MOISTURE THERE BUT
THE HRRR AND LOCAL WRF MODELS SHOW HIGHEST PRECIP AMOUNTS SLIPPING
TO THE SOUTH. STILL EXPECT POPS THERE TO BE HIGH SCATTERED THROUGH
THE REST OF THE NIGHT.
&&
.AVIATION...BRIEF MVFR IS POSSIBLE IN THE ONSHORE MOVING SHOWERS BUT
COVERAGE IS TOO LOW TO CARRY MENTION OF IN THE TAFS...EXCEPT
POSSIBLY AT KFPR/KSUA. SOME IFR STRATUS WAS EARLIER NOTED AT KLEE
BUT GENERALLY WOULD EXPECT CEILINGS AT OR ABOVE FL020 FOR THE
INTERIOR TAFS. NORTHEAST WINDS SHOULD STAY GUSTY AT MOST OF THE
COASTAL TERMINALS EXCEPT KTIX-KDAB OVERNIGHT...THEN ALL SITES WILL
BE GUSTY AGAIN ON SUNDAY.
&&
.MARINE... TONIGHT-SUNDAY...915MHZ CAPE WIND PROFILERS SHOW A LOW
LEVEL WIND SURGE OCCURRING WITH 30 KNOT WINDS JUST ABOVE THE
SURFACE...SO EXPECT SIMILAR GUSTS OVER THE MARINE AREA...POSSIBLY TO
NEAR GALE FORCE TONIGHT. THE GFS SHOWS A SLOW DECREASE IN THE
PRESSURE GRADIENT AND GUST POTENTIAL LATE TONIGHT THROUGH SUNDAY
AFTERNOON. STILL...CONDITIONS FOR SMALL CRAFT OPERATION WILL REMAIN
HAZARDOUS THROUGH THE DAY WITH OPEN ATLANTIC SEAS 8-10 FEET.
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...HIGH SURF ADVISORY UNTIL 4 PM EST SUNDAY FOR COASTAL VOLUSIA
COUNTY-INDIAN RIVER-MARTIN-NORTHERN BREVARD COUNTY-SOUTHERN
BREVARD COUNTY-ST. LUCIE.
AM...SMALL CRAFT ADVISORY UNTIL 4 AM EST MONDAY FOR FLAGLER BEACH TO
VOLUSIA-BREVARD COUNTY LINE 0-20 NM-FLAGLER BEACH TO
VOLUSIA-BREVARD COUNTY LINE 20-60 NM-SEBASTIAN INLET TO
JUPITER INLET 0-20 NM-SEBASTIAN INLET TO JUPITER INLET 20-
60 NM-VOLUSIA-BREVARD COUNTY LINE TO SEBASTIAN INLET 0-20
NM-VOLUSIA-BREVARD COUNTY LINE TO SEBASTIAN INLET 20-60 NM.
&&
$$
SHORT TERM...LASCODY
IMPACT WX....ULRICH
AREA FORECAST DISCUSSION
NWS MIAMI FL
1251 PM EST FRI DEC 4 2015
.AVIATION...
AFTER A BRIEF LULL LATE THIS MORNING...SHOWERS ARE AGAIN SPREADING
NORTHWESTWARD OVER MIAMI-DADE TERMINALS...AND WILL LIKELY IMPACT
BROWARD TAF SITES BY 19Z. THUS...SHRA IN FORECAST THROUGH THIS
EVENING EAST COAST...THEN COVERAGE SHOULD BECOME MORE SCATTERED
AND WENT WITH PREVAILING VCSH FOR DURATION OF PERIOD. NAPLES MAY
NOT RECEIVE MUCH ADDITIONAL SHOWERS...BUT LOW CIGS...AT LEAST
MVFR...ARE EXPECTED TO PERSIST INTO SATURDAY MORNING. FOR EASTERN
TERMINALS...PERIODS OF MVFR ARE EXPECTED...BUT THINK VFR
CONDITIONS WILL BE MORE DOMINANT...SO WENT WITH ONLY TEMPO MVFR
CIGS FOR REMAINDER OF TODAY. WIND 5-10 KT TODAY WILL BECOME NE
AROUND 10 KT TONIGHT AND SATURDAY.
&&
.PREV DISCUSSION... /ISSUED 1007 AM EST FRI DEC 4 2015/
UPDATE...
RAIN COVERAGE ACROSS SOUTH FLORIDA IS FINALLY BEGINNING TO
SUBSIDE. WATER VAPOR IMAGERY SHOWING THE DEEPER MOISTURE HAS MOVED
OFFSHORE. THE RAP13 ANALYSIS OF THE UPPER LEVEL WIND SHOWING THE
BEST DIVERGENCE ALOFT HAS MOVED TO THE SOUTHEAST, WHICH
CORRESPONDS TO THE BETTER RAIN COVERAGE, AS WELL AS THE HEAVIER
SHOWERS AND THUNDERSTORMS. THE HRRR HAS BEEN HANDLING THE COVERAGE
FAIRLY WELL AND HAS MOST OF THE RAIN ENDING, EXCEPT FOR SOME
SHOWER ACTIVITY REDEVELOPING IN THE LAKE REGION. HAVE BROUGHT
POPS DOWN SOME, BUT HAVE LEFT LIKELY POPS IN THE FORECAST FOR MOST
OF THE ATLANTIC COASTAL METRO AREAS, ESPECIALLY FROM BROWARD,
NORTH.
PREV DISCUSSION... /ISSUED 729 AM EST FRI DEC 4 2015/
AVIATION...
WIDESPREAD RAIN AND SHOWERS LOOK TO CONTINUE THROUGH MUCH OF THE
DAY. PERIODS OF SIGNIFICANT RESTRICTIONS ARE POSSIBLE...BUT
MAJORITY OF TIME EXPECT VFR CONDITIONS. EAST WIND AROUND 10 KT
THROUGH THE PERIOD.
PREV DISCUSSION... /ISSUED 400 AM EST FRI DEC 4 2015/
DISCUSSION...
COLD FRONT EARLY THIS MORNING WAS ALIGNED FROM MAINLAND MONROE
COUNTY TO NORTHERN BROWARD COUNTY. THIS FRONT IS FORECAST TO SAG
SLOWLY SOUTHEASTWARD AND BE POSITIONED OFF THE SOUTHEAST FLORIDA
COAST TONIGHT. HIGH PRESSURE BUILDING NORTH OF THE FRONT WILL LEAD
TO INCREASING NORTHEASTERLY WINDS FROM N-S BEHIND THIS FRONT.
DEEP TROPICAL MOISTURE WILL CONTINUE ACROSS BROWARD/MIAMI-DADE
NEAR THE FRONTAL BOUNDARY TODAY-TONIGHT BEFORE DRIER AIR MOVES IN
FROM THE NORTHWEST. GPS MET DATA SHOWS PW AT MIAMI AT AROUND 2.25
INCHES. VERY IMPRESSIVE AND NEAR THE MAXIMUM RECORDED FOR THE
MONTH OF DECEMBER! PW AT BOTH NAPLES AND OKEECHOBEE WAS NEAR 1.9
INCHES. GIVEN THE IMPRESSIVE MOISTURE, THE ATMOSPHERE IS RIPE FOR
HEAVY RAINFALL PRODUCTION NEAR/IN ADVANCE OF THE FRONT OVER MIAMI-
DADE AND BROWARD. WAVES OF LOCALLY HEAVY RAINFALL ARE FORECAST TO
CONTINUE TO MOVE IN FROM THE SOUTHWEST TODAY ACROSS BROWARD/MIAMI-
DADE WITH LESS INTENSITY POINTS NORTH AND WEST. GIVEN RECENT HEAVY
RAINFALL IN SOME LOCALES OVER THE PAST 24 HOURS...ADDITIONAL
LOCALIZED HEAVY RAINFALL (3"+ POSSIBLE) COULD LEAD TO FLOODING AT
SOME LOCALES ACROSS THE MIAMI AND FORT LAUDERDALE METRO AREAS. AS
SUCH...CONTINUED THE FLOOD WATCH FOR BROWARD /MIAMI-DADE THROUGH
SAT MORNING. RAIN INTENSITY IS EXPECTED TO BE LESS POINTS NORTH
AND WEST...SO NO NEED TO EXPAND THE WATCH ELSEWHERE.
A FEW TSTORMS WILL CONTINUE...ESPECIALLY ACROSS THE ATLANTIC
WATERS, BUT POSSIBLE OVER LAND AS WELL TODAY. THE LACK THOUGH OF
APPRECIABLE INSTABILITY IS EXPECTED TO KEEP TSTORMS ORDINARY IN
NATURE WITH LIGHTNING/HEAVY RAIN THE THREATS.
AS WINDS TURN NORTHEAST BEHIND THE FRONT AND MOISTURE LAGS
BEHIND...CONVERGENCE ALONG THE EAST COAST IS FORECAST TO KEEP
SHOWERS GOING, ESPECIALLY ALONG THE COAST WHERE THE HEAVY RAIN
THREAT COULD CONTINUE THROUGH TONIGHT INTO EARLY SATURDAY.
THE FORECAST SUNDAY INTO MID WEEK FEATURES CONTINUED CHANCES OF
SHOWERS AS A NE WIND CONTINUES ALONG WITH SUFFICIENT MOISTURE TO
SUPPORT SHOWERS FOCUSED ALONG THE ATLANTIC COAST...WITH LESSER
CHANCES INLAND AND TO THE GULF COAST. BOTH GFS AND ECMWF SHOW
A SHORTWAVE MOVING ACROSS THE GULF DURING THE MIDDLE PART OF NEXT
WEEK WHICH COULD LEAD TO PERHAPS INCREASED SHOWER ACTIVITY THEN.
TEMPS CONTINUE ABOVE AVERAGE THROUGH NEXT WEEK...AND NO SIGNS OF
ANY SIGNIFICANT COOLING HERE. IN FACT, THE 540DM 1000-500 MB
THICKNESS LINE (OFTEN LOOKED AT FOR RAIN-SNOW LINE), RESIDES IN
CANADA TO THE NORTH OF MINNESOTA FOR MUCH OF NEXT WEEK...VERY
IMPRESSIVE FOR DECEMBER! #ELNINO /GREGORIA
MARINE...
COLD FRONT OVER THE LOCAL WATERS, STRETCHING EARLY THIS MORNING
FROM OFF THE BROWARD COUNTY COAST TO THE GULF WATERS OFF THE
MAINLAND MONROE COUNTY COAST, WILL SAG SLOWLY SOUTHEAST THROUGH
TONIGHT WITH NORTHEASTERLY WINDS INCREASING BEHIND THE FRONT. HIGH
PRESSURE BUILDING NORTH OF THE FRONT WILL RESULT IN A MODERATE TO
FRESH NORTHEAST WIND FLOW PREVAILING THROUGH THE WEEKEND.
A SMALL CRAFT ADVISORY HAS BEEN ISSUED FOR THE OFFSHORE GULF
WATERS EFFECTIVE THIS AFTERNOON THROUGH EARLY MONDAY.
A SMALL CRAFT ADVISORY HAS BEEN ISSUED FOR THE ATLANTIC WATERS
EFFECTIVE THIS EVENING THROUGH MONDAY MORNING AS GULF STREAM SEAS
BUILD TO 7+ FEET. /GREGORIA
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 74 82 76 83 / 40 60 50 50
FORT LAUDERDALE 69 80 72 81 / 50 60 50 50
MIAMI 71 81 73 82 / 50 60 50 50
NAPLES 66 84 68 84 / 30 40 20 30
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...FLOOD WATCH THROUGH SATURDAY MORNING FOR FLZ071>074-172>174.
AM...SMALL CRAFT ADVISORY FROM 7 PM THIS EVENING TO 7 AM EST MONDAY
FOR AMZ650-651-670-671.
GM...SMALL CRAFT ADVISORY UNTIL 10 AM EST SUNDAY FOR GMZ676.
&&
$$
SHORT TERM...13/SI
LONG TERM....57/DG
AVIATION...23/SK
AREA FORECAST DISCUSSION
NWS MIAMI FL
1007 AM EST FRI DEC 4 2015
.UPDATE...
RAIN COVERAGE ACROSS SOUTH FLORIDA IS FINALLY BEGINNING TO
SUBSIDE. WATER VAPOR IMAGERY SHOWING THE DEEPER MOISTURE HAS MOVED
OFFSHORE. THE RAP13 ANALYSIS OF THE UPPER LEVEL WIND SHOWING THE
BEST DIVERGENCE ALOFT HAS MOVED TO THE SOUTHEAST, WHICH
CORRESPONDS TO THE BETTER RAIN COVERAGE, AS WELL AS THE HEAVIER
SHOWERS AND THUNDERSTORMS. THE HRRR HAS BEEN HANDLING THE COVERAGE
FAIRLY WELL AND HAS MOST OF THE RAIN ENDING, EXCEPT FOR SOME
SHOWER ACTIVITY REDEVELOPING IN THE LAKE REGION. HAVE BROUGHT
POPS DOWN SOME, BUT HAVE LEFT LIKELY POPS IN THE FORECAST FOR MOST
OF THE ATLANTIC COASTAL METRO AREAS, ESPECIALLY FROM BROWARD,
NORTH.
&&
.PREV DISCUSSION... /ISSUED 729 AM EST FRI DEC 4 2015/
AVIATION...
WIDESPREAD RAIN AND SHOWERS LOOK TO CONTINUE THROUGH MUCH OF THE
DAY. PERIODS OF SIGNIFICANT RESTRICTIONS ARE POSSIBLE...BUT
MAJORITY OF TIME EXPECT VFR CONDITIONS. EAST WIND AROUND 10 KT
THROUGH THE PERIOD.
PREV DISCUSSION... /ISSUED 400 AM EST FRI DEC 4 2015/
DISCUSSION...
COLD FRONT EARLY THIS MORNING WAS ALIGNED FROM MAINLAND MONROE
COUNTY TO NORTHERN BROWARD COUNTY. THIS FRONT IS FORECAST TO SAG
SLOWLY SOUTHEASTWARD AND BE POSITIONED OFF THE SOUTHEAST FLORIDA
COAST TONIGHT. HIGH PRESSURE BUILDING NORTH OF THE FRONT WILL LEAD
TO INCREASING NORTHEASTERLY WINDS FROM N-S BEHIND THIS FRONT.
DEEP TROPICAL MOISTURE WILL CONTINUE ACROSS BROWARD/MIAMI-DADE
NEAR THE FRONTAL BOUNDARY TODAY-TONIGHT BEFORE DRIER AIR MOVES IN
FROM THE NORTHWEST. GPS MET DATA SHOWS PW AT MIAMI AT AROUND 2.25
INCHES. VERY IMPRESSIVE AND NEAR THE MAXIMUM RECORDED FOR THE
MONTH OF DECEMBER! PW AT BOTH NAPLES AND OKEECHOBEE WAS NEAR 1.9
INCHES. GIVEN THE IMPRESSIVE MOISTURE, THE ATMOSPHERE IS RIPE FOR
HEAVY RAINFALL PRODUCTION NEAR/IN ADVANCE OF THE FRONT OVER MIAMI-
DADE AND BROWARD. WAVES OF LOCALLY HEAVY RAINFALL ARE FORECAST TO
CONTINUE TO MOVE IN FROM THE SOUTHWEST TODAY ACROSS BROWARD/MIAMI-
DADE WITH LESS INTENSITY POINTS NORTH AND WEST. GIVEN RECENT HEAVY
RAINFALL IN SOME LOCALES OVER THE PAST 24 HOURS...ADDITIONAL
LOCALIZED HEAVY RAINFALL (3"+ POSSIBLE) COULD LEAD TO FLOODING AT
SOME LOCALES ACROSS THE MIAMI AND FORT LAUDERDALE METRO AREAS. AS
SUCH...CONTINUED THE FLOOD WATCH FOR BROWARD /MIAMI-DADE THROUGH
SAT MORNING. RAIN INTENSITY IS EXPECTED TO BE LESS POINTS NORTH
AND WEST...SO NO NEED TO EXPAND THE WATCH ELSEWHERE.
A FEW TSTORMS WILL CONTINUE...ESPECIALLY ACROSS THE ATLANTIC
WATERS, BUT POSSIBLE OVER LAND AS WELL TODAY. THE LACK THOUGH OF
APPRECIABLE INSTABILITY IS EXPECTED TO KEEP TSTORMS ORDINARY IN
NATURE WITH LIGHTNING/HEAVY RAIN THE THREATS.
AS WINDS TURN NORTHEAST BEHIND THE FRONT AND MOISTURE LAGS
BEHIND...CONVERGENCE ALONG THE EAST COAST IS FORECAST TO KEEP
SHOWERS GOING, ESPECIALLY ALONG THE COAST WHERE THE HEAVY RAIN
THREAT COULD CONTINUE THROUGH TONIGHT INTO EARLY SATURDAY.
THE FORECAST SUNDAY INTO MID WEEK FEATURES CONTINUED CHANCES OF
SHOWERS AS A NE WIND CONTINUES ALONG WITH SUFFICIENT MOISTURE TO
SUPPORT SHOWERS FOCUSED ALONG THE ATLANTIC COAST...WITH LESSER
CHANCES INLAND AND TO THE GULF COAST. BOTH GFS AND ECMWF SHOW
A SHORTWAVE MOVING ACROSS THE GULF DURING THE MIDDLE PART OF NEXT
WEEK WHICH COULD LEAD TO PERHAPS INCREASED SHOWER ACTIVITY THEN.
TEMPS CONTINUE ABOVE AVERAGE THROUGH NEXT WEEK...AND NO SIGNS OF
ANY SIGNIFICANT COOLING HERE. IN FACT, THE 540DM 1000-500 MB
THICKNESS LINE (OFTEN LOOKED AT FOR RAIN-SNOW LINE), RESIDES IN
CANADA TO THE NORTH OF MINNESOTA FOR MUCH OF NEXT WEEK...VERY
IMPRESSIVE FOR DECEMBER! #ELNINO /GREGORIA
MARINE...
COLD FRONT OVER THE LOCAL WATERS, STRETCHING EARLY THIS MORNING
FROM OFF THE BROWARD COUNTY COAST TO THE GULF WATERS OFF THE
MAINLAND MONROE COUNTY COAST, WILL SAG SLOWLY SOUTHEAST THROUGH
TONIGHT WITH NORTHEASTERLY WINDS INCREASING BEHIND THE FRONT. HIGH
PRESSURE BUILDING NORTH OF THE FRONT WILL RESULT IN A MODERATE TO
FRESH NORTHEAST WIND FLOW PREVAILING THROUGH THE WEEKEND.
A SMALL CRAFT ADVISORY HAS BEEN ISSUED FOR THE OFFSHORE GULF
WATERS EFFECTIVE THIS AFTERNOON THROUGH EARLY MONDAY.
A SMALL CRAFT ADVISORY HAS BEEN ISSUED FOR THE ATLANTIC WATERS
EFFECTIVE THIS EVENING THROUGH MONDAY MORNING AS GULF STREAM SEAS
BUILD TO 7+ FEET. /GREGORIA
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 78 74 82 76 / 70 40 60 50
FORT LAUDERDALE 77 69 80 72 / 70 50 60 50
MIAMI 78 71 81 73 / 60 50 60 50
NAPLES 76 66 84 68 / 30 30 40 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...FLOOD WATCH THROUGH SATURDAY MORNING FOR FLZ071>074-172>174.
AM...SMALL CRAFT ADVISORY FROM 7 PM THIS EVENING TO 7 AM EST MONDAY
FOR AMZ650-651-670-671.
GM...SMALL CRAFT ADVISORY UNTIL 10 AM EST SUNDAY FOR GMZ676.
&&
$$
SHORT TERM...13/SI
LONG TERM....57/DG
AREA FORECAST DISCUSSION...UPDATED
NWS MIAMI FL
1245 AM EST FRI DEC 4 2015
.AVIATION...
ISOLATED TO SCATTERED SHOWERS WILL CONTINUE OVER ALL OF THE TAF
SITES THROUGH FRIDAY. THE CEILING AND VIS WILL BE CAPABLE OF
FALLING DOWN INTO THE MVFR CONDITIONS WITH THE PASSAGE OF THE
SHOWERS. THE ONLY EXCEPTION TO THIS IS THAT KAPF TAF SITE WILL
REMAIN IN THE IFR CONDITIONS FOR THE CEILINGS THROUGH THE EARLY
MORNING HOURS.
THE WINDS WILL BE MAINLY LIGHT AND VARIABLE OVER THE EAST COAST
TAF SITES EARLY THIS MORNING BEFORE BECOMING NORTHEAST AROUND 10
KNOTS FOR THE DAY HOURS OF FRIDAY. FOR KAPF TAF SITE...THE WINDS
WILL REMAIN NORTHEAST AROUND 10 KNOTS THIS MORNING INTO FRIDAY DAY
HOURS.
&&
.UPDATE...54/BNB
.PREV DISCUSSION... /ISSUED 659 PM EST THU DEC 3 2015/
UPDATE...
FLOOD WATCH WAS ISSUED FOR ALL OF MIAMI-DADE AND BROWARD COUNTIES.
HEAVY RAINFALL IS EXPECTED WITH SHOWERS AND THUNDERSTORMS NOW
MOVING NORTHEAST THIS EVENING. ADDITIONAL HEAVY RAIN WILL DEVELOP
OVERNIGHT AND THROUGH FRIDAY NIGHT ACROSS OF ALL OF SOUTH FLORIDA,
WHICH WILL EXACERBATE CONDITIONS, AS A STALLING COLD FRONT
INTERACTS WITH DEEP TROPICAL MOISTURE. THE FLOOD WATCH MAY NEED TO
BE EXPANDED NORTH AND WEST WITH FUTURE UPDATES.
&&
AVIATION...
SHOWERS AND STORMS ASSOC WITH LINE NOW MOVING NORTHEAST WILL
AFFECT MIA/OPF/TMB IN THE NEXT FEW HOURS. ADDITIONAL HVY SHOWERS
AND SOME THUNDERSTORMS MAY DEVELOP THROUGH THE TAF PERIOD, AS DEEP
TROPICAL MOISTURE INTERACTS WITH A STALLING COLD FRONT. SOME
IFR/MVFR VIS/CIGS CONDS ARE POSSIBLE AS THIS LINE MOVES THROUGH
THE REGION THIS EVENING WITH GUSTS TO 35 KTS.
&&
PREV DISCUSSION... /ISSUED 332 PM EST THU DEC 3 2015/
DISCUSSION...
STEADY STREAM OF HEAVY SHOWERS AND EMBEDDED THUNDERSTORMS
FROM CUBA INTO THE KEYS, HAVE HAD A DIFFICULT TIME HOLDING
TOGETHER INTO THE PENINSULA THIS AFTERNOON. DESPITE THIS NEAR TERM
MODELS, ESPECIALLY THE HRRR CONTINUE TO FORECAST THESE CLUSTERS
EVENTUALLY ENTERING SOUTH FLORIDA LATE THIS AFTERNOON. THE HRRR
HAS BEEN FAR TOO AGGRESSIVE THIS AFTERNOON, SO SKEPTICAL OF THIS
ARRIVAL TIME. ABUNDANT CLOUDS HAVE ALSO PREVENTED ANY DEVELOPMENT
DUE TO DAYTIME HEATING SO FAR. UNDER THIS REGIME, TYPICALLY
OFFSHORE HVY SHOWERS AND THUNDERSTORMS HAVE MUCH BETTER SUCCESS
CROSSING LAND DURING THE EVENING AND OVERNIGHT HOURS. HOWEVER,
STILL CAN`T RULE OUT DEVELOPMENT DURING THE DAYTIME HOURS WITH THE
EAST COAST SEABREEZE POTENTIALLY LEADING TO ENOUGH SURFACE
CONVERGENCE/LIFT FOR WET WEATHER ALONG THE EAST COAST METRO. THIS
SEEMS TO BE OCCURRING IN BROWARD/FLL/FXE ATTM AND PARTS OF
INTERIOR MIAMI-DADE.
OVERALL, SOME CHANGES IN THE MODELS. STRONGER WINDS FORECASTED
BY THE MODELS TO AFFECT ALL OF THE EAST COAST AND ATLANTIC
WATERS, NOW ONLY MAKE IT TO PALM BEACH COUNTY. THIS MAY INDICATE
THAT THE WEAKENING COLD FRONT MAY NOT MAKE IT AS FAR SOUTH AS
PREVIOUSLY THOUGHT. SURFACE HIGH PRESSURE IS CENTERED A LITTLE
FURTHER NORTH THROUGH THE MIDDLE ATLANTIC WHICH LEADS TO LESS OF A
PRESSURE GRADIENT ALONG EXTREME SOUTH FL. THUS THERE IS A
DEVELOPING TREND TOWARDS THE HEAVIEST RAINFALL OCCURRING OVER THE
NORTHERN HALF OF THE FORECAST AREA, AS HEAVIEST QPF FROM THE
GFS/ECMWF HAS SHIFTED NORTH. REGARDLESSS, CAN`T PUT MUCH STOCK IN
RUN TO RUN VARIANCES, SO THE HEAVY RAIN THREAT CONTINUES FOR ALL
OF SOUTH FLORIDA.
FOR TONIGHT AND THE FIRST HALF OF FRIDAY, ADDITIONAL FORCING
PROVIDED BY A FEW MIDLEVEL DISTURBANCES AND MORE FAVORABLE
ORIENTATION OF THE UPPER JET, MAY BE THE EXTRA BOOST NEEDED TO
SPARK DEVELOPMENT. WIND FIELD REMAINS FAVORABLE FOR TRAINING AND
BACKBUILDING, ALSO LLVL HELICITY IS FAVORABLE FOR STRONGER STORMS.
WITH THE LACK OF ACTIVITY THUS FAR THIS PM, WILL HOLD OFF ON A
FLOOD WATCH AND CONTINUE TO ASSESS LATER THIS PM. WITH THE SLOWER
PROGRESSION OF THE FRONT, THE GFS DOES INDICATE SOME HEAVIER RAIN
REMAINING ACROSS THE SOUTHERN CWA INTO SATURDAY MORNING, WHEREAS
THE ECMWF HAS BACKED OFF. BOTH MODELS INDICATE A MIDLEVEL
DISTURBANCE CROSSING THE FL STRAITS AND KEYS, CLIPPING EXTREME SE
FL AROUND 6Z SAT. TOUGH TO ASCERTAIN HOW MUCH QPF FROM BOTH MODELS
ARE BEING INFLUENCED BY CONVECTIVE FEEDBACK. STRONGER MIDLEVEL SW
FLOW DOES SEEM TO END FRIDAY EVENING, WHICH WOULD SEEM TO CUTOFF
THE TRANSPORT OF ANOMALOUS MOISTURE ACROSS THE REGION, ALTHOUGH
PWATS WILL STILL BE ELEVATED. BY SATURDAY PM WINDS BECOME EASTERLY
THROUGH H85 AND ONSHORE FLOW WILL BE RESPONSIBLE FOR SHOWERS ALONG
THE EAST COAST. A SIMILAR SETUP IS EXPECTED ON SUNDAY.
DIFFUSE BOUNDARY WAVERS OVER SOUTH FL THROUGH MONDAY. INTO
MIDWEEK, A STRONGER COLD FRONT MOVING THROUGH THE SOUTHEAST CONUS
MAY FINALLY SHOVE THE WEAK BOUNDARY SOUTH USHERING IN DRIER AIR
WITH DEWPOINTS FALLING INTO THE MIDDLE 50S ACROSS THE
INTERIOR/LAKE REGION. HOWEVER, THE GFS IS FASTER WITH THIS
PROGRESSION WHEREAS THE ECMWF LAGS, WITH A WETTER FORECAST FOR
WEDNESDAY. THE GFS IS ALSO MUCH COOLER BEHIND THIS FRONT THAN THE
ECMWF
MARINE...
NUMEROUS SHOWERS AND SOME STRONGER THUNDERSTORMS EXPECTED AS A
WEAK COLD FRONT STALLS INTO SATURDAY AM. LATEST GUIDANCE
INDICATES THAT SMALL CRAFT ADV LEVEL WINDS MAY ONLY MAKE TO THE
ATLANTIC WATERS OFF PALM BEACH COUNTY. WIND SPEEDS MAY STAY AROUND
10 KTS FARTHER SOUTH. WAVE HEIGHTS ALONG THE GULF STREAM THOUGH
ARE STILL EXPECTED TO BE 7 FT AND ABOVE, HIGHEST OFFSHORE PALM
BEACH COUNTY. A WEAK TO MODERATE SWELL WILL ROLL DOWN THE EAST
COAST SAT AND SAT NIGHT. WAVES SUBSIDE SUNDAY NIGHT.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 74 80 74 83 / 60 70 50 50
FORT LAUDERDALE 69 79 71 83 / 80 70 50 50
MIAMI 71 81 71 83 / 80 70 50 50
NAPLES 68 82 69 84 / 40 30 30 40
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...FLOOD WATCH THROUGH SATURDAY MORNING FOR FLZ071>074-172>174.
AM...NONE.
GM...NONE.
&&
$$
SHORT TERM...54/BNB
LONG TERM....21/KM
AVIATION...54/BNB
AREA FORECAST DISCUSSION
National Weather Service Lincoln IL
1143 AM CST FRI DEC 4 2015
.UPDATE...
ISSUED AT 1047 AM CST FRI DEC 4 2015
High pressure still building into the region, with light winds
under the ridge. However, short term in eastern Illinois is
dominated by the persistent fog that is slow to burn off. Have
extended the fog advisory through midday. Sat imagery starting to
show some erosion on the western border of the fog bank. Some
minor updates to the hourlies based on the slower response of the
diurnal curve in the east as a result of the fog. Will be altering
some of the high temps as well. Update out momentarily.
&&
.SHORT TERM...(Today)
ISSUED AT 328 AM CST FRI DEC 4 2015
Persistent area of low clouds continues to blanket locations east of
the I-55 corridor early this morning. 09z/3am obs also show
widespread dense fog across this area, prompting the issuance of a
Dense Fog Advisory along/east of a Bloomington...to Decatur...to
Taylorville line. With high pressure centered over the Ohio River
Valley, very light S/SW low-level flow has been noted across the
northern half of the CWA: however, winds on the back side of the
high are beginning to take on a S/SE component across south-central
Illinois. IR satellite imagery is showing the low clouds/fog
inching westward just south of Taylorville, with the latest HRRR
suggesting this moisture might curl northward into the Springfield
and Lincoln areas in the next few hours. Will keep an eye on
satellite trends to see if this comes to pass and advisory needs to
be expanded westward to I-55. Due to the low sun angle and only
light low-level flow, fog will be slow to dissipate today. In fact,
HRRR suggests the far E/NE CWA near the Indiana border may remain
overcast for much of the day. Have extended the Dense Fog Advisory
until 17z/11am, but have kept skies mostly cloudy along and
northeast of a Champaign to Paris line until mid to late afternoon.
The evolution of the fog/clouds will have a big impact on high
temperatures. Based on expected trends, have kept readings coolest
in the lower 40s near Danville and Paris, with highs reaching the
upper 40s to around 50 elsewhere.
.LONG TERM...(Tonight through Thursday)
ISSUED AT 328 AM CST FRI DEC 4 2015
While the HRRR and Rapid Refresh have generally done a good job with
the low clouds/fog this morning, the NAM and especially the GFS have
not. In fact, GFS soundings indicate mostly clear skies and
unrestricted visbys today! As a result, am very skeptical about
forecast soundings from both models tonight. The GFS is again
clear: however, the NAM hints at low-level saturation and possible
fog. The high pressure center currently near Evansville, Indiana is
expected to shift into southern Ohio tonight, with the corresponding
ridge axis extending southwestward into the Ozarks. This will
result in the lightest winds across the E/SE CWA, with only a light
S/SW flow further north and west. Given persistent weather pattern,
have decided to include patchy fog mention along/southeast of a
Champaign to Taylorville line once again tonight. Once any morning
fog burns off, mostly sunny skies will prevail on Saturday. Thanks
to a good deal of sunshine and light southerly winds, afternoon high
temperatures will climb at least 10 degrees above normal for this
time of year into the lower 50s.
00z Dec 4 models are still having difficulty with the exact timing
and track of the next approaching short-wave early next week. The
ECMWF is about 6-12 hours faster with the wave than the GFS,
bringing it across central Illinois Sunday afternoon. Meanwhile,
the GFS is more amplified and slower, tracking the feature across
the area Sunday night into Monday. Run-to-run consistency remains
poor with both models, but will stick with the slightly more stable
GFS here. As synoptic lift increases ahead of the wave, clouds will
be on the increase on Sunday. The airmass will initially be quite
dry due to the presence of the strong surface ridge early in the
period, so moisture will remain limited. As a result, will only
feature a slight chance PoP for rain across the W/SW CWA Sunday
afternoon, then mainly across the S/SE Sunday night. These low
chance PoPs may need to be extended into Monday as well if the GFS
verifies. After that, models bring a series of ill-defined weak
short-waves across the CONUS through next week. Pinning down the
exact timing of these features within the zonal flow pattern will be
difficult. Given this fact and the overall lack of deep-layer
moisture, will continue with a mild and dry forecast through the
remainder of the extended.
&&
.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
ISSUED AT 1141 AM CST FRI DEC 4 2015
Aviation concerns remain the same. Longevity of the VLIFR in the
east is finally abating at CMI and DEC to LIFR, and slow
improvement is expected in the next few hours. However, the longer
it lasts, the less of the llvl RH mixes out and the chances for
the fog returning in the morning goes up considerably. Have at
least started the trend for CMI to drop with a predominant, and
DEC with a tempo. Without the fog, SKC and light southerly flow
anticipated.
&&
.ILX Watches/Warnings/Advisories...
Dense Fog Advisory until 1 PM CST this afternoon for ILZ043>046-
053>057-061>063-066>068-071>073.
&&
$$
UPDATE...HJS
SHORT TERM...Barnes
LONG TERM...Barnes
AVIATION...HJS
AREA FORECAST DISCUSSION
National Weather Service Lincoln IL
1117 AM CST FRI DEC 4 2015
.UPDATE...
ISSUED AT 1047 AM CST FRI DEC 4 2015
High pressure still building into the region, with light winds
under the ridge. However, short term in eastern Illinois is
dominated by the persistent fog that is slow to burn off. Have
extended the fog advisory through midday. Sat imagery starting to
show some erosion on the western border of the fog bank. Some
minor updates to the hourlies based on the slower response of the
diurnal curve in the east as a result of the fog. Will be altering
some of the high temps as well. Update out momentarily.
&&
.SHORT TERM...(Today)
ISSUED AT 328 AM CST FRI DEC 4 2015
Persistent area of low clouds continues to blanket locations east of
the I-55 corridor early this morning. 09z/3am obs also show
widespread dense fog across this area, prompting the issuance of a
Dense Fog Advisory along/east of a Bloomington...to Decatur...to
Taylorville line. With high pressure centered over the Ohio River
Valley, very light S/SW low-level flow has been noted across the
northern half of the CWA: however, winds on the back side of the
high are beginning to take on a S/SE component across south-central
Illinois. IR satellite imagery is showing the low clouds/fog
inching westward just south of Taylorville, with the latest HRRR
suggesting this moisture might curl northward into the Springfield
and Lincoln areas in the next few hours. Will keep an eye on
satellite trends to see if this comes to pass and advisory needs to
be expanded westward to I-55. Due to the low sun angle and only
light low-level flow, fog will be slow to dissipate today. In fact,
HRRR suggests the far E/NE CWA near the Indiana border may remain
overcast for much of the day. Have extended the Dense Fog Advisory
until 17z/11am, but have kept skies mostly cloudy along and
northeast of a Champaign to Paris line until mid to late afternoon.
The evolution of the fog/clouds will have a big impact on high
temperatures. Based on expected trends, have kept readings coolest
in the lower 40s near Danville and Paris, with highs reaching the
upper 40s to around 50 elsewhere.
.LONG TERM...(Tonight through Thursday)
ISSUED AT 328 AM CST FRI DEC 4 2015
While the HRRR and Rapid Refresh have generally done a good job with
the low clouds/fog this morning, the NAM and especially the GFS have
not. In fact, GFS soundings indicate mostly clear skies and
unrestricted visbys today! As a result, am very skeptical about
forecast soundings from both models tonight. The GFS is again
clear: however, the NAM hints at low-level saturation and possible
fog. The high pressure center currently near Evansville, Indiana is
expected to shift into southern Ohio tonight, with the corresponding
ridge axis extending southwestward into the Ozarks. This will
result in the lightest winds across the E/SE CWA, with only a light
S/SW flow further north and west. Given persistent weather pattern,
have decided to include patchy fog mention along/southeast of a
Champaign to Taylorville line once again tonight. Once any morning
fog burns off, mostly sunny skies will prevail on Saturday. Thanks
to a good deal of sunshine and light southerly winds, afternoon high
temperatures will climb at least 10 degrees above normal for this
time of year into the lower 50s.
00z Dec 4 models are still having difficulty with the exact timing
and track of the next approaching short-wave early next week. The
ECMWF is about 6-12 hours faster with the wave than the GFS,
bringing it across central Illinois Sunday afternoon. Meanwhile,
the GFS is more amplified and slower, tracking the feature across
the area Sunday night into Monday. Run-to-run consistency remains
poor with both models, but will stick with the slightly more stable
GFS here. As synoptic lift increases ahead of the wave, clouds will
be on the increase on Sunday. The airmass will initially be quite
dry due to the presence of the strong surface ridge early in the
period, so moisture will remain limited. As a result, will only
feature a slight chance PoP for rain across the W/SW CWA Sunday
afternoon, then mainly across the S/SE Sunday night. These low
chance PoPs may need to be extended into Monday as well if the GFS
verifies. After that, models bring a series of ill-defined weak
short-waves across the CONUS through next week. Pinning down the
exact timing of these features within the zonal flow pattern will be
difficult. Given this fact and the overall lack of deep-layer
moisture, will continue with a mild and dry forecast through the
remainder of the extended.
&&
.AVIATION...(For the 12Z TAFS through 12Z Saturday morning)
ISSUED AT 505 AM CST FRI DEC 4 2015
Variable conditions exist across the TAF forecast area with VLIFR
conditions prevailing just east of I-55, while MVFR and IFR
conditions are being reported west of the interstate. This will
continue through about 17z before we see a significant improvement
with confidence low for DEC and CMI where sounding data suggests
it may not be until 19z before vsbys and cigs improve. Even if we
do see cigs and vsbys come up across the east this afternoon, it
appears the setup will be about the same tonight as the surface
high and light wind fields prevail across the forecast area. Look
for light southerly winds today with speeds of 10 kts or less. The
winds will gradually back into a light southeast flow tonight.
&&
.ILX Watches/Warnings/Advisories...
Dense Fog Advisory until 1 PM CST this afternoon for ILZ043>046-
053>057-061>063-066>068-071>073.
&&
$$
UPDATE...HJS
SHORT TERM...Barnes
LONG TERM...Barnes
AVIATION...Smith
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
825 AM CST FRI DEC 4 2015
.SHORT TERM...
256 AM CST
THROUGH SATURDAY NIGHT...
EARLY THIS MORNING...HIGH PRESSURE IS CENTERED ACROSS THE LOWER
OHIO VALLEY WITH RIDGING EXTENDING ACROSS THE UPPER MIDWEST.
SATELLITE IMAGERY AND AREA OBSERVATIONS SHOWS LOW STRATUS ACROSS
MUCH OF NORTHEAST AND EAST CENTRAL ILLINOIS AND NORTHWEST INDIANA.
WHILE THE BACK EDGE HAS BEEN STEADILY ERODING FROM THE WEST ACROSS
PORTIONS OF FAR NORTHERN ILLINOIS OVERNIGHT...SOUTH OF I-80 THE
STRATUS HAS BEEN SPREADING NORTH...AND LOWERING WITH VISIBILITY
DROPPING BELOW A MILE IN SEVERAL LOCATIONS. GENERALLY LIKE
HRRR/RAP CIG/VSBY TRENDS PARTICULARLY SOUTH OF I-80 WHERE THE
GREATEST THREAT OF AT LEAST SOME PATCHY DENSE FOG APPEARS TO BE
THIS MORNING. WILL CONTINUE TO MONITOR TRENDS CLOSELY AS A DENSE
FOG ADVISORY MAY BE NEEDED FOR SOME AREAS. CLOUD COVER WILL BE
SLOW TO ERODE TODAY...THOUGH THE NORTHWEST HALF OR SO OF THE CWA
SHOULD SEE SUNSHINE BY THIS AFTERNOON. ALONG AND SOUTHEAST OF A
FAIRBURY IL TO VALPARAISO IN LINE EXPECT STRATUS TO LINGER INTO
THE AFTERNOON...LONGEST FOR PORTIONS OF NORTHWEST INDIANA WHERE
TEMPERATURES WERE LOWERED A FEW DEGREES ACCORDINGLY.
OVERNIGHT AMDAR SOUNDINGS OUT OF CHICAGO SHOW SHARP TEMPERATURE
INVERSION BASED AROUND 950MB WITH TEMPS QUICKLY WARMING TO AROUND
+7C BETWEEN 925MB AND 850MB. SEASONAL CLIMO SUGGESTS THAT THESE
TEMPERATURES ALOFT WOULD SUPPORT AFTERNOON HIGHS FROM THE MID 40S
TO LOW 50S AND WHILE EARLY MORNING CLOUDS/FOG COULD SLOW THE
WARMING...SHOULD SEE TEMPERATURES JUMP ONCE THE SUN COMES OUT.
SEVERAL MODELS INCLUDING THE GFS AND NAM ARE WAY TOO COLD WITH
UNREALISTIC IMPACTS FROM MODEL SNOW DEPTH. SIMILARLY FOR
SATURDAY... WENT ON THE WARMER END OF THE SPECTRUM FOR
TEMPERATURES WITH THERMAL RIDGE PUSHING OVERHEAD AND SEVERAL
MODELS CONTINUING TO STRUGGLE WITH SURFACE TEMPS DUE TO SNOW.
FORECASTING AFTERNOON HIGHS IN THE UPPER 40S TO LOW 50S WITH A
LIGHT SOUTH BREEZE THROUGH THE DAY.
DEUBELBEISS
&&
.LONG TERM...
256 AM CST
SATURDAY NIGHT THROUGH THURSDAY...
SUNDAY THROUGH THURSDAY...
UPPER RIDGE THAT BRINGS UNSEASONABLE WARMTH TO THE AREA WILL
CONTINUE TO PROGRESS EAST INTO THE ATLANTIC SUNDAY WHILE UPPER LOW
IS PROGGED TO CUT OFF ACROSS THE MISSISSIPPI VALLEY. THERE ARE
TIMING DIFFERENCES BETWEEN THE MODEL SOLUTIONS WITH THE NAM AND
ECWMF LEADING THE GFS WITH FASTER SOLUTIONS BY 6-12HRS...AND THE
GFS REMAINS SLIGHTLY SLOWER THAN EVEN THE GEFS MEAN. UPPER LOW
WILL BRING WITH IT SOMEWHAT COOLER TEMPERATURES WITH H85 TEMPS
PROGGED TO FALL BACK BELOW 0C BRIEFLY SUNDAY WHICH WILL RESULT IN
SUNDAY TEMPERATURES ONLY MAXING OUT IN THE 40S...WHICH IS STILL
WELL ABOVE NORMAL. COULD BE SLIGHTLY WARMER SUNDAY IF THE SLOWER
GFS VERIFIES BUT OTHERWISE TIMING DIFFERENCES BETWEEN THE MODELS
SOMEWHAT MOOT AS OVERALL FORCING WITH THIS SYSTEM IS WEAK AND
MOISTURE IS MEAGER SO DONT ANTICIPATE MUCH IF ANYTHING AS FAR AS
QPF OR POPS. NAM CONTINUES TO SHOW MOISTENING LOW LEVELS WITH
DRIZZLE DEVELOPING BUT NOT READY TO BITE OFF ON THIS YET AS
SOUNDINGS LEADING UP TO THIS EVENT SHOW A FAIRLY DEEP LAYER OR DRY
AIR THAT MAY BE DIFFICULT TO OVERCOME.
UPPER LOW CONTINUES TO THE EAST COAST BY LATE MONDAY WITH A MODEST
UPPER RIDGE AND WARMER AIR OVERSPREADING THE LOCAL AREA BY LATE
MONDAY. THEN...UPPER PATTERN IS PROGGED TO BECOME MORE ZONAL FROM
TUESDAY ON WITH A SERIES OF SHORTWAVES DIGGING INTO THE MIDWEST
THE LATTER HALF OF THE WEEK. CONFIDENCE IN THE DETAILS DROPS
CONSIDERABLY WITH SIGNIFICANT TIMING AND TRACK DIFFERENCES IN THE
MODELS...WITH THE ECMWF IN PARTICULAR ADVERTISING A MORE ACTIVE
AND WET PATTERN FOR THE LOCAL AREA. ADDED SOME PERIODS OF SLIGHT
POPS PER GENERAL MODEL CONSENSUS BUT OTHERWISE DID NOT MAKE ANY
SIGNIFICANT CHANGES TO THE FORECAST FOR THE UPCOMING WEEK AND
EXPECT ABOVE NORMAL TEMPS TO CONTINUE.
DEUBELBEISS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 14Z...
* BRIEF PERIOD OF IFR CIG/VIS THIS MORNING.
RATZER/BEACHLER
//DISCUSSION...UPDATED 12Z...
SLOW MOVING BANK OF LOW STRATUS HAS SEEN REDEVELOPMENT ALONG THE
TRAILING EDGE OVERNIGHT...WITH LOWER CIGS 200-600 FT AND IFR/LIFR
VIS IN A FEW SPOTS WHERE CLOUD DECK HAD REDEVELOPED/BUILT DOWN TO
NEAR THE SURFACE. IR SATELLITE TRENDS CONTINUE TO SHOW EROSION
FROM THE WEST/NORTH/NORTHEAST ACROSS FAR NORTHEAST IL...THOUGH IT
APPEARS AREA BETWEEN ORD-DPA-ARR MAY BE THE LAST TO ERODE OVER THE
NEXT FEW HOURS. LOWEST CONDITIONS HAVE BEEN AND ARE EXPECTED TO
REMAIN IN THE ARR-DPA AREA...WITH IMPROVEMENT AREA-WIDE BY MID-
MORNING. RAP SHORT TERM GUIDANCE HANDLING TRENDS FAIRLY WELL...
LENDING SUPPORT TO SATELLITE TRENDS THIS MORNING. ONCE CLEARING
OCCURS...VFR CONDITIONS EXPECTED FOR REMAINDER OF THE FORECAST
PERIOD.
SOUTHWEST WINDS 10 KTS OR LESS EXPECTED THROUGH THE PERIOD...AS
SURFACE HIGH PRESSURE PROPAGATES THROUGH THE OHIO VALLEY. WIND
DIRECTION LIKELY TO BECOME A LITTLE MORE SOUTH ON SATURDAY AS THE
CENTER OF THE HIGH MOVES OFF TO THE EAST.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* HIGH IN CIG/VIS TRENDS THIS MORNING...THOUGH MEDIUM IN EXACT CIG
HGT/VIS.
RATZER/BEACHLER
//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...
SATURDAY NIGHT THROUGH THURSDAY...VFR. WX NIL. WINDS WEST TO
SOUTH WITH WINDS GENERALLY AT OR UNDER 10KT.
RATZER
&&
.MARINE...
320 AM CST
HIGH PRESSURE WILL BE STRENGTHENING AND EXPANDING ACROSS THE OHIO
VALLEY TODAY WHILE A LOW PRESSURE TROUGH MOVES AWAY TO THE
NORTHEAST OF THE LAKES. WEST WINDS GUSTING 25-30 KTS EARLIER WILL
GRADUALLY DIMINISH AND BACK SOUTHWEST TODAY AS WEAKER RIDGING
DEVELOPS ACROSS THE WESTERN LAKES. ANOTHER LOW WILL LIFT ACROSS
CANADA AND HUDSON BAY TONIGHT AND SATURDAY...TIGHTENING THE
GRADIENT ACROSS LAKE MICHIGAN AND INCREASING WINDS AGAIN LATE
TODAY AND TONIGHT ESPECIALLY ACROSS THE NORTHERN PARTS OF THE
LAKE...WHERE WINDS WILL INCREASE TO NEAR 30 KT ON SATURDAY AND
SATURDAY NIGHT WITH A FEW MARGINAL GALE GUSTS POSSIBLE ESPECIALLY
SATURDAY EVENING. THE CANADIAN LOW WILL TRAIL A WEAK COLD FRONT
ACROSS THE LAKE ON SUNDAY...WITH A WEAKENING OF THE GRADIENT AND A
WIND SHIFT BRIEFLY BACK TO THE WEST AS WEAK HIGH PRESSURE RIDGE
BUILDS IN SUNDAY NIGHT. LONGER RANGE PATTERN FAVORS PERSISTENT
SOUTH-SOUTHWEST WINDS ACROSS THE LAKE EARLY NEXT WEEK...WITH
ANOTHER LOW MOVING FROM NEAR LAKE WINNIPEG TO HUDSON BAY MONDAY
AND TUESDAY.
RATZER
&&
.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
NWS CHICAGO/ROMEOVILLE IL
548 AM CST FRI DEC 4 2015
.SHORT TERM...
256 AM CST
THROUGH SATURDAY NIGHT...
EARLY THIS MORNING...HIGH PRESSURE IS CENTERED ACROSS THE LOWER
OHIO VALLEY WITH RIDGING EXTENDING ACROSS THE UPPER MIDWEST.
SATELLITE IMAGERY AND AREA OBSERVATIONS SHOWS LOW STRATUS ACROSS
MUCH OF NORTHEAST AND EAST CENTRAL ILLINOIS AND NORTHWEST INDIANA.
WHILE THE BACK EDGE HAS BEEN STEADILY ERODING FROM THE WEST ACROSS
PORTIONS OF FAR NORTHERN ILLINOIS OVERNIGHT...SOUTH OF I-80 THE
STRATUS HAS BEEN SPREADING NORTH...AND LOWERING WITH VISIBILITY
DROPPING BELOW A MILE IN SEVERAL LOCATIONS. GENERALLY LIKE
HRRR/RAP CIG/VSBY TRENDS PARTICULARLY SOUTH OF I-80 WHERE THE
GREATEST THREAT OF AT LEAST SOME PATCHY DENSE FOG APPEARS TO BE
THIS MORNING. WILL CONTINUE TO MONITOR TRENDS CLOSELY AS A DENSE
FOG ADVISORY MAY BE NEEDED FOR SOME AREAS. CLOUD COVER WILL BE
SLOW TO ERODE TODAY...THOUGH THE NORTHWEST HALF OR SO OF THE CWA
SHOULD SEE SUNSHINE BY THIS AFTERNOON. ALONG AND SOUTHEAST OF A
FAIRBURY IL TO VALPARAISO IN LINE EXPECT STRATUS TO LINGER INTO
THE AFTERNOON...LONGEST FOR PORTIONS OF NORTHWEST INDIANA WHERE
TEMPERATURES WERE LOWERED A FEW DEGREES ACCORDINGLY.
OVERNIGHT AMDAR SOUNDINGS OUT OF CHICAGO SHOW SHARP TEMPERATURE
INVERSION BASED AROUND 950MB WITH TEMPS QUICKLY WARMING TO AROUND
+7C BETWEEN 925MB AND 850MB. SEASONAL CLIMO SUGGESTS THAT THESE
TEMPERATURES ALOFT WOULD SUPPORT AFTERNOON HIGHS FROM THE MID 40S
TO LOW 50S AND WHILE EARLY MORNING CLOUDS/FOG COULD SLOW THE
WARMING...SHOULD SEE TEMPERATURES JUMP ONCE THE SUN COMES OUT.
SEVERAL MODELS INCLUDING THE GFS AND NAM ARE WAY TOO COLD WITH
UNREALISTIC IMPACTS FROM MODEL SNOW DEPTH. SIMILARLY FOR
SATURDAY... WENT ON THE WARMER END OF THE SPECTRUM FOR
TEMPERATURES WITH THERMAL RIDGE PUSHING OVERHEAD AND SEVERAL
MODELS CONTINUING TO STRUGGLE WITH SURFACE TEMPS DUE TO SNOW.
FORECASTING AFTERNOON HIGHS IN THE UPPER 40S TO LOW 50S WITH A
LIGHT SOUTH BREEZE THROUGH THE DAY.
DEUBELBEISS
&&
.LONG TERM...
256 AM CST
SATURDAY NIGHT THROUGH THURSDAY...
SUNDAY THROUGH THURSDAY...
UPPER RIDGE THAT BRINGS UNSEASONABLE WARMTH TO THE AREA WILL
CONTINUE TO PROGRESS EAST INTO THE ATLANTIC SUNDAY WHILE UPPER LOW
IS PROGGED TO CUT OFF ACROSS THE MISSISSIPPI VALLEY. THERE ARE
TIMING DIFFERENCES BETWEEN THE MODEL SOLUTIONS WITH THE NAM AND
ECWMF LEADING THE GFS WITH FASTER SOLUTIONS BY 6-12HRS...AND THE
GFS REMAINS SLIGHTLY SLOWER THAN EVEN THE GEFS MEAN. UPPER LOW
WILL BRING WITH IT SOMEWHAT COOLER TEMPERATURES WITH H85 TEMPS
PROGGED TO FALL BACK BELOW 0C BRIEFLY SUNDAY WHICH WILL RESULT IN
SUNDAY TEMPERATURES ONLY MAXING OUT IN THE 40S...WHICH IS STILL
WELL ABOVE NORMAL. COULD BE SLIGHTLY WARMER SUNDAY IF THE SLOWER
GFS VERIFIES BUT OTHERWISE TIMING DIFFERENCES BETWEEN THE MODELS
SOMEWHAT MOOT AS OVERALL FORCING WITH THIS SYSTEM IS WEAK AND
MOISTURE IS MEAGER SO DONT ANTICIPATE MUCH IF ANYTHING AS FAR AS
QPF OR POPS. NAM CONTINUES TO SHOW MOISTENING LOW LEVELS WITH
DRIZZLE DEVELOPING BUT NOT READY TO BITE OFF ON THIS YET AS
SOUNDINGS LEADING UP TO THIS EVENT SHOW A FAIRLY DEEP LAYER OR DRY
AIR THAT MAY BE DIFFICULT TO OVERCOME.
UPPER LOW CONTINUES TO THE EAST COAST BY LATE MONDAY WITH A MODEST
UPPER RIDGE AND WARMER AIR OVERSPREADING THE LOCAL AREA BY LATE
MONDAY. THEN...UPPER PATTERN IS PROGGED TO BECOME MORE ZONAL FROM
TUESDAY ON WITH A SERIES OF SHORTWAVES DIGGING INTO THE MIDWEST
THE LATTER HALF OF THE WEEK. CONFIDENCE IN THE DETAILS DROPS
CONSIDERABLY WITH SIGNIFICANT TIMING AND TRACK DIFFERENCES IN THE
MODELS...WITH THE ECMWF IN PARTICULAR ADVERTISING A MORE ACTIVE
AND WET PATTERN FOR THE LOCAL AREA. ADDED SOME PERIODS OF SLIGHT
POPS PER GENERAL MODEL CONSENSUS BUT OTHERWISE DID NOT MAKE ANY
SIGNIFICANT CHANGES TO THE FORECAST FOR THE UPCOMING WEEK AND
EXPECT ABOVE NORMAL TEMPS TO CONTINUE.
DEUBELBEISS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 12Z...
* BRIEF PERIOD OF IFR CIG/VIS THIS MORNING.
RATZER
//DISCUSSION...UPDATED 12Z...
SLOW MOVING BANK OF LOW STRATUS HAS SEEN REDEVELOPMENT ALONG THE
TRAILING EDGE OVERNIGHT...WITH LOWER CIGS 200-600 FT AND IFR/LIFR
VIS IN A FEW SPOTS WHERE CLOUD DECK HAD REDEVELOPED/BUILT DOWN TO
NEAR THE SURFACE. IR SATELLITE TRENDS CONTINUE TO SHOW EROSION
FROM THE WEST/NORTH/NORTHEAST ACROSS FAR NORTHEAST IL...THOUGH IT
APPEARS AREA BETWEEN ORD-DPA-ARR MAY BE THE LAST TO ERODE OVER THE
NEXT FEW HOURS. LOWEST CONDITIONS HAVE BEEN AND ARE EXPECTED TO
REMAIN IN THE ARR-DPA AREA...WITH IMPROVEMENT AREA-WIDE BY MID-
MORNING. RAP SHORT TERM GUIDANCE HANDLING TRENDS FAIRLY WELL...
LENDING SUPPORT TO SATELLITE TRENDS THIS MORNING. ONCE CLEARING
OCCURS...VFR CONDITIONS EXPECTED FOR REMAINDER OF THE FORECAST
PERIOD.
SOUTHWEST WINDS 10 KTS OR LESS EXPECTED THROUGH THE PERIOD...AS
SURFACE HIGH PRESSURE PROPAGATES THROUGH THE OHIO VALLEY. WIND
DIRECTION LIKELY TO BECOME A LITTLE MORE SOUTH ON SATURDAY AS THE
CENTER OF THE HIGH MOVES OFF TO THE EAST.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 12Z...
* HIGH IN CIG/VIS TRENDS THIS MORNING...THOUGH MEDIUM IN EXACT CIG
HGT/VIS.
RATZER
//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...
SATURDAY NIGHT THROUGH THURSDAY...VFR. WX NIL. WINDS WEST TO
SOUTH WITH WINDS GENERALLY AT OR UNDER 10KT.
RATZER
&&
.MARINE...
320 AM CST
HIGH PRESSURE WILL BE STRENGTHENING AND EXPANDING ACROSS THE OHIO
VALLEY TODAY WHILE A LOW PRESSURE TROUGH MOVES AWAY TO THE
NORTHEAST OF THE LAKES. WEST WINDS GUSTING 25-30 KTS EARLIER WILL
GRADUALLY DIMINISH AND BACK SOUTHWEST TODAY AS WEAKER RIDGING
DEVELOPS ACROSS THE WESTERN LAKES. ANOTHER LOW WILL LIFT ACROSS
CANADA AND HUDSON BAY TONIGHT AND SATURDAY...TIGHTENING THE
GRADIENT ACROSS LAKE MICHIGAN AND INCREASING WINDS AGAIN LATE
TODAY AND TONIGHT ESPECIALLY ACROSS THE NORTHERN PARTS OF THE
LAKE...WHERE WINDS WILL INCREASE TO NEAR 30 KT ON SATURDAY AND
SATURDAY NIGHT WITH A FEW MARGINAL GALE GUSTS POSSIBLE ESPECIALLY
SATURDAY EVENING. THE CANADIAN LOW WILL TRAIL A WEAK COLD FRONT
ACROSS THE LAKE ON SUNDAY...WITH A WEAKENING OF THE GRADIENT AND A
WIND SHIFT BRIEFLY BACK TO THE WEST AS WEAK HIGH PRESSURE RIDGE
BUILDS IN SUNDAY NIGHT. LONGER RANGE PATTERN FAVORS PERSISTENT
SOUTH-SOUTHWEST WINDS ACROSS THE LAKE EARLY NEXT WEEK...WITH
ANOTHER LOW MOVING FROM NEAR LAKE WINNIPEG TO HUDSON BAY MONDAY
AND TUESDAY.
RATZER
&&
.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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WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
National Weather Service Lincoln IL
508 AM CST FRI DEC 4 2015
.SHORT TERM...(Today)
ISSUED AT 328 AM CST FRI DEC 4 2015
Persistent area of low clouds continues to blanket locations east of
the I-55 corridor early this morning. 09z/3am obs also show
widespread dense fog across this area, prompting the issuance of a
Dense Fog Advisory along/east of a Bloomington...to Decatur...to
Taylorville line. With high pressure centered over the Ohio River
Valley, very light S/SW low-level flow has been noted across the
northern half of the CWA: however, winds on the back side of the
high are beginning to take on a S/SE component across south-central
Illinois. IR satellite imagery is showing the low clouds/fog
inching westward just south of Taylorville, with the latest HRRR
suggesting this moisture might curl northward into the Springfield
and Lincoln areas in the next few hours. Will keep an eye on
satellite trends to see if this comes to pass and advisory needs to
be expanded westward to I-55. Due to the low sun angle and only
light low-level flow, fog will be slow to dissipate today. In fact,
HRRR suggests the far E/NE CWA near the Indiana border may remain
overcast for much of the day. Have extended the Dense Fog Advisory
until 17z/11am, but have kept skies mostly cloudy along and
northeast of a Champaign to Paris line until mid to late afternoon.
The evolution of the fog/clouds will have a big impact on high
temperatures. Based on expected trends, have kept readings coolest
in the lower 40s near Danville and Paris, with highs reaching the
upper 40s to around 50 elsewhere.
.LONG TERM...(Tonight through Thursday)
ISSUED AT 328 AM CST FRI DEC 4 2015
While the HRRR and Rapid Refresh have generally done a good job with
the low clouds/fog this morning, the NAM and especially the GFS have
not. In fact, GFS soundings indicate mostly clear skies and
unrestricted visbys today! As a result, am very skeptical about
forecast soundings from both models tonight. The GFS is again
clear: however, the NAM hints at low-level saturation and possible
fog. The high pressure center currently near Evansville, Indiana is
expected to shift into southern Ohio tonight, with the corresponding
ridge axis extending southwestward into the Ozarks. This will
result in the lightest winds across the E/SE CWA, with only a light
S/SW flow further north and west. Given persistent weather pattern,
have decided to include patchy fog mention along/southeast of a
Champaign to Taylorville line once again tonight. Once any morning
fog burns off, mostly sunny skies will prevail on Saturday. Thanks
to a good deal of sunshine and light southerly winds, afternoon high
temperatures will climb at least 10 degrees above normal for this
time of year into the lower 50s.
00z Dec 4 models are still having difficulty with the exact timing
and track of the next approaching short-wave early next week. The
ECMWF is about 6-12 hours faster with the wave than the GFS,
bringing it across central Illinois Sunday afternoon. Meanwhile,
the GFS is more amplified and slower, tracking the feature across
the area Sunday night into Monday. Run-to-run consistency remains
poor with both models, but will stick with the slightly more stable
GFS here. As synoptic lift increases ahead of the wave, clouds will
be on the increase on Sunday. The airmass will initially be quite
dry due to the presence of the strong surface ridge early in the
period, so moisture will remain limited. As a result, will only
feature a slight chance PoP for rain across the W/SW CWA Sunday
afternoon, then mainly across the S/SE Sunday night. These low
chance PoPs may need to be extended into Monday as well if the GFS
verifies. After that, models bring a series of ill-defined weak
short-waves across the CONUS through next week. Pinning down the
exact timing of these features within the zonal flow pattern will be
difficult. Given this fact and the overall lack of deep-layer
moisture, will continue with a mild and dry forecast through the
remainder of the extended.
&&
.AVIATION...(For the 12Z TAFS through 12Z Saturday morning)
ISSUED AT 505 AM CST FRI DEC 4 2015
Variable conditions exist across the TAF forecast area with VLIFR
conditions prevailing just east of I-55, while MVFR and IFR
conditions are being reported west of the interstate. This will
continue through about 17z before we see a significant improvement
with confidence low for DEC and CMI where sounding data suggests
it may not be until 19z before vsbys and cigs improve. Even if we
do see cigs and vsbys come up across the east this afternoon, it
appears the setup will be about the same tonight as the surface
high and light wind fields prevail across the forecast area. Look
for light southerly winds today with speeds of 10 kts or less. The
winds will gradually back into a light southeast flow tonight.
&&
.ILX Watches/Warnings/Advisories...
Dense Fog Advisory until 11 AM CST this morning for ILZ038-
043>046-052>057-061>063-066>068-071>073.
&&
$$
SHORT TERM...Barnes
LONG TERM...Barnes
AVIATION...Smith
AREA FORECAST DISCUSSION
National Weather Service Lincoln IL
328 AM CST FRI DEC 4 2015
.SHORT TERM...(Today)
ISSUED AT 328 AM CST FRI DEC 4 2015
Persistent area of low clouds continues to blanket locations east of
the I-55 corridor early this morning. 09z/3am obs also show
widespread dense fog across this area, prompting the issuance of a
Dense Fog Advisory along/east of a Bloomington...to Decatur...to
Taylorville line. With high pressure centered over the Ohio River
Valley, very light S/SW low-level flow has been noted across the
northern half of the CWA: however, winds on the back side of the
high are beginning to take on a S/SE component across south-central
Illinois. IR satellite imagery is showing the low clouds/fog
inching westward just south of Taylorville, with the latest HRRR
suggesting this moisture might curl northward into the Springfield
and Lincoln areas in the next few hours. Will keep an eye on
satellite trends to see if this comes to pass and advisory needs to
be expanded westward to I-55. Due to the low sun angle and only
light low-level flow, fog will be slow to dissipate today. In fact,
HRRR suggests the far E/NE CWA near the Indiana border may remain
overcast for much of the day. Have extended the Dense Fog Advisory
until 17z/11am, but have kept skies mostly cloudy along and
northeast of a Champaign to Paris line until mid to late afternoon.
The evolution of the fog/clouds will have a big impact on high
temperatures. Based on expected trends, have kept readings coolest
in the lower 40s near Danville and Paris, with highs reaching the
upper 40s to around 50 elsewhere.
&&
.LONG TERM...(Tonight through Thursday)
ISSUED AT 328 AM CST FRI DEC 4 2015
While the HRRR and Rapid Refresh have generally done a good job with
the low clouds/fog this morning, the NAM and especially the GFS have
not. In fact, GFS soundings indicate mostly clear skies and
unrestricted visbys today! As a result, am very skeptical about
forecast soundings from both models tonight. The GFS is again
clear: however, the NAM hints at low-level saturation and possible
fog. The high pressure center currently near Evansville, Indiana is
expected to shift into southern Ohio tonight, with the corresponding
ridge axis extending southwestward into the Ozarks. This will
result in the lightest winds across the E/SE CWA, with only a light
S/SW flow further north and west. Given persistent weather pattern,
have decided to include patchy fog mention along/southeast of a
Champaign to Taylorville line once again tonight. Once any morning
fog burns off, mostly sunny skies will prevail on Saturday. Thanks
to a good deal of sunshine and light southerly winds, afternoon high
temperatures will climb at least 10 degrees above normal for this
time of year into the lower 50s.
00z Dec 4 models are still having difficulty with the exact timing
and track of the next approaching short-wave early next week. The
ECMWF is about 6-12 hours faster with the wave than the GFS,
bringing it across central Illinois Sunday afternoon. Meanwhile,
the GFS is more amplified and slower, tracking the feature across
the area Sunday night into Monday. Run-to-run consistency remains
poor with both models, but will stick with the slightly more stable
GFS here. As synoptic lift increases ahead of the wave, clouds will
be on the increase on Sunday. The airmass will initially be quite
dry due to the presence of the strong surface ridge early in the
period, so moisture will remain limited. As a result, will only
feature a slight chance PoP for rain across the W/SW CWA Sunday
afternoon, then mainly across the S/SE Sunday night. These low
chance PoPs may need to be extended into Monday as well if the GFS
verifies. After that, models bring a series of ill-defined weak
short-waves across the CONUS through next week. Pinning down the
exact timing of these features within the zonal flow pattern will be
difficult. Given this fact and the overall lack of deep-layer
moisture, will continue with a mild and dry forecast through the
remainder of the extended.
&&
.AVIATION...(For the 06Z TAFS through 06Z Friday night)
ISSUED AT 1141 PM CST THU DEC 3 2015
Challenging forecast, especially for BMI/DEC and possibly CMI.
Conditions have dropped to VLIFR with vis below 3/4sm and cigs
below 500ft. Believe there will be some fluctuations with the
cig/vis for couple of hours at BMI and DEC but then think they
will both go down to 1/4sm FG and cigs around 100-200 ft for most
of the night and then gradually improve during the morning hours.
SPI and PIA should remain clear but have some light fog on and off
late tonight through early tomorrow morning. CMI will remain
cloudy all night with some light fog as well. Cloudy/foggy sites
will see improvement during the afternoon and should become clear
during that time frame. Additional fog looks possible tomorrow
night, so have TEMPO group at all sites for light fog around 3sm.
Winds will be out of the south to southwest remainder of the night
and then become southerly tomorrow. Speeds should be lighter with
high pressure building into the area, but stronger winds see at
BMI where the worst vis is located at.
&&
.ILX Watches/Warnings/Advisories...
Dense Fog Advisory until 11 AM CST this morning for ILZ038-
043>046-052>057-061>063-066>068-071>073.
&&
$$
SHORT TERM...Barnes
LONG TERM...Barnes
AVIATION...Auten
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
557 PM EST FRI DEC 4 2015
.SYNOPSIS...
ISSUED AT 300 PM EST FRI DEC 4 2015
LOW CLOUDS AND FOG WILL QUICKLY FORM TONIGHT ACROSS MUCH OF THE
AREA AND PERSIST INTO AT LEAST SATURDAY MORNING. SOME OF THE FOG
COULD BE LOCALLY DENSE WITH VISIBILITIES LESS THAN ONE QUARTER
MILE...ESPECIALLY NORTHEAST OF ROUTE 30. LOWS WILL DROP INTO THE
UPPER 20S. CLOUDS AND FOG SHOULD SLOWLY LIFT THROUGH THE DAY
SATURDAY WITH HIGHS REACHING WELL INTO THE 40S.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 300 PM EST FRI DEC 4 2015
FAIRLY DRASTIC OVERALL TO GRIDS FOR TONIGHT INTO SATURDAY MORNING
TO REFLECT INCREASING CONCERNS FOR RAPID REDEVELOPMENT OF WIDESPREAD
STRATUS AND FOG (POSSIBLY DENSE) ACROSS THE AREA. VIS SAT AND
OBSERVATIONS SHOW SCOURING OUT OF STRATUS DECK CONTINUES...BUT WILL
LIKELY REACH THE END OF THIS OCCURRING IN THE NEXT HOUR OR 2 AS PEAK
HEATING AND MIXING DIMINISHES. DESPITE THE CLEARING A SLOW INCREASE
IN LOW LEVEL MSTR COMBINED WITH LIGHT WINDS AND MOSTLY CLEAR TO
CLEAR SKIES WILL SET THE STAGE FOR RAPID DEVELOPMENT OF STRATUS
ACROSS THE AREA THIS EVENING. HRRR HAS BEEN HANDLING OVERALL SETUP
QUITE WELL BOTH LAST NIGHT AND TODAY AND QUICKLY BRINGS STRATUS AND
DENSE FOG BACK IN BETWEEN 3 AND 6Z SAT. GRIDS NOW REFLECT A RETURN
TO CLOUDY SKIES BY LATE EVENING WITH PATCHY FOG
INITIALLY...EVENTUALLY GOING TO AREAS OF FOG. WHERE FULL CLEARING
HAS TAKEN PLACE...A MENTION OF PATCHY DENSE FREEZING FOG HAS BEEN
ADDED AS TEMPS DROP BELOW FREEZING ACROSS THE AREA AND GREATER
CONCENTRATION OF WATER DROPLETS MAY GIVE A LIGHT GLAZE ON ELEVATED
SURFACES. FOR NOW WILL HOLD OFF ON ANY HEADLINES AND DEFER TO EVE
SHIFT TO MONITOR TRENDS AS COULD END UP MAINLY THE STRATUS ISSUE AND
VSBYS BEHAVE THEMSELVES.
NEXT CHALLENGE WILL BE IF THE STRATUS/FOG CAN LIFT DURING THE DAY
SATURDAY AS INVERSION REMAINS IN PLACE. CLEARING MAY BE HIGHLY
DEPENDENT ON ACTUAL DEPTH OF THE STRATUS DECK. TODAY IT WAS ON
THE THINNER SIDE AND ALLOWED AT LEAST SOME MIXING. THIS MAY NOT BE
THE CASE TOMORROW AS RIDGE AXIS SHIFTS OVERHEAD AND POTENTIALLY
TRAPS THE LOW CLOUDS AND SOME FOG THROUGH THE DAY. FOR NOW WILL
KEEP WITH AT LEAST SOME CLEARING...BUT EXTENSIVE UPDATE CHANGES
MAY BE NEEDED IN LATER FORECASTS. WILL GO WITH GENERAL PERSISTENCE
ON TEMPS AS WELL WITH BUST POTENTIAL MODERATE TO HIGH.
&&
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 300 PM EST FRI DEC 4 2015
LONG TERM PERIOD BEGINS QUIETLY...WITH LARGE SCALE RIDGE AXIS
CENTERED EAST OF THE REGION SUNDAY AND UPPER TROF/CUTOFF LOW
APPROACHING THE REGION FROM THE WEST. CONTINUED WITH A DRY FORECAST
OF 14 POPS OR LESS SUNDAY NIGHT/EARLY MONDAY AS THIS SYSTEM PASSES
THROUGH THE REGION...WITH A BULK OF THE FORCING AND MOISTURE
REMAINING SOUTH OF THE REGION.
A ZONAL FLOW REGIME TAKES HOLD ACROSS THE CONUS THROUGH MUCH OF NEXT
WEEK. THE MAIN FORECAST CHALLENGE WILL BE EMBEDDED SHORTWAVES
TRACKING THROUGH THIS ZONAL FLOW REGIME AND POTENTIAL PRECIPITATION
FOR THE FORECAST AREA. LONG TERM MODEL SOLUTIONS DIFFER WITH THE
HANDLING OF THESE SYSTEMS. WENT WITH A CONSENSUS BLEND APPROACH
WHICH YIELDED SLIGHT CHANCE POPS WEDNESDAY THROUGH THE END OF THE
PERIOD. HONED THESE POPS DOWN TO WEDNESDAY AND WED NIGHT
TIMEFRAME...WHICH QUICK MOVING WAVE TRACKS SOMEWHERE THROUGH THE
REGION...BUT KEPT POPS LESS THAN 20 PERCENT. WENT WITH A CONTINUED
DRY FORECAST THURSDAY AND THURSDAY NIGHT...BUT KEPT THE CONSENSUS
BLEND SOLUTION FOR FRIDAY WITH VERY LOW CHANCE POPS. TOWARD THE END
OF NEXT WEEK...THE OVERALL PATTERN BECOMES MORE AMPLIFIED AS STRONG
EPAC UPPER JET BUCKLES...WITH DEEPER TROUGHING OVER THE WRN CONUS
AND DOWNSTREAM ERN CONUS RIDGING. WHEN THIS ENERGY EJECTS THROUGH
THE REGION SOMETIME TOWARDS THE END OF THE WEEK/NEXT WEEKEND...THIS
WOULD INCREASE PRECIPITATION CHANCES GREATLY. HOWEVER LONG RANGE
MODELS DIFFER GREATLY WITH TIMING/EVOLUTION OF THIS SYSTEM...WHICH
COULD BRING A DECENT RAINFALL TO THE AREA DEPENDING ON THE
EVOLUTION. FOR NOW...WITH STICK WITH THE LOW CHANCE POPS FOR
FRIDAY...BUT THIS WILL BE THE TIME PERIOD TO WATCH FOR THE NEXT
CHANCE OF A DECENT RAINFALL FOR THE REGION.
OTHERWISE...TEMPS THROUGH THE PERIOD WILL BE MILD FOR EARLY/MID
DECEMBER STANDARDS...WITH HIGHS IN THE LOW TO MID 40S SUNDAY THROUGH
TUESDAY...AND MID TO UPPER 40S AND POSSIBLE 50S LATER IN THE PERIOD.
LOW TEMPS THROUGH THE PERIOD WILL START OUT AT OR BELOW FREEZING SAT
NIGHT AND SUN NIGHT...THEN WARMING THROUGH THE 30S EACH NIGHT
THROUGH THE END OF THE PERIOD. THIS WOULD YIELD POTENTIAL AVERAGE
TEMPS NEARLY 10 DEGREES ABOVE NORMAL BY THE END OF THE FORECAST
PERIOD.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 557 PM EST FRI DEC 4 2015
WIDESPREAD IFR CONDS XPCD AGAIN OVERNIGHT INTO SAT AM AS STAGNANT
SFC RIDGE PERSISTS THROUGH THE OH VALLEY. MOIST BNDRY LYR REMAINS
TRAPPED BENEATH LL THERMAL INVERSION. PRIOR WK DIURNALLY PEAKED
MIXING HAS DIMINISHED W/SUNDOWN AND ALREADY SEEING A INCREASING
NEWD EXPANSION OF EXISTING WEDGE CNTRD ACRS WRN IN. BOTH NR AND
SHRT TERM GUIDANCE OUTSIDE HRRR SOLUTION WORTHLESS W/CURRENT AND
PROGGED SCENARIO GOING FWD THUS SIDED SIG GRID UPDATE TWD HRRR.
NEWD PROGRESSION OF SFC RIDGE CNTR TWD WRN LK ERIE SAT AM ALG
W/INCREASING SWRLY FLW ALG WRN FLANK DOES PORTENT BTR MIXING
POTENTIAL TWD ERLY AFTN AND WILL FOLLOW OBSVD PERSISTENCE OB
TRENDS FM TDA IN 00Z TERMINAL FCSTS.
OTRWS HYDRO LAPSE RATES SUGGEST FOG WILL BECOME MORE OF AN ISSUE
ESP TWD SUNRISE W/A PD OF LIFR VSBYS PSBL.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SYNOPSIS...FISHER
SHORT TERM...FISHER
LONG TERM...NG
AVIATION...T
VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)
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AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
304 PM EST FRI DEC 4 2015
.SYNOPSIS...
ISSUED AT 300 PM EST FRI DEC 4 2015
LOW CLOUDS AND FOG WILL QUICKLY FORM TONIGHT ACROSS MUCH OF THE
AREA AND PERSIST INTO AT LEAST SATURDAY MORNING. SOME OF THE FOG
COULD BE LOCALLY DENSE WITH VISIBILITIES LESS THAN ONE QUARTER
MILE...ESPECIALLY NORTHEAST OF ROUTE 30. LOWS WILL DROP INTO THE
UPPER 20S. CLOUDS AND FOG SHOULD SLOWLY LIFT THROUGH THE DAY
SATURDAY WITH HIGHS REACHING WELL INTO THE 40S.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 300 PM EST FRI DEC 4 2015
FAIRLY DRASTIC OVERALL TO GRIDS FOR TONIGHT INTO SATURDAY MORNING
TO REFLECT INCREASING CONCERNS FOR RAPID REDEVELOPMENT OF WIDESPREAD
STRATUS AND FOG (POSSIBLY DENSE) ACROSS THE AREA. VIS SAT AND
OBSERVATIONS SHOW SCOURING OUT OF STRATUS DECK CONTINUES...BUT WILL
LIKELY REACH THE END OF THIS OCCURRING IN THE NEXT HOUR OR 2 AS PEAK
HEATING AND MIXING DIMINISHES. DESPITE THE CLEARING A SLOW INCREASE
IN LOW LEVEL MSTR COMBINED WITH LIGHT WINDS AND MOSTLY CLEAR TO
CLEAR SKIES WILL SET THE STAGE FOR RAPID DEVELOPMENT OF STRATUS
ACROSS THE AREA THIS EVENING. HRRR HAS BEEN HANDLING OVERALL SETUP
QUITE WELL BOTH LAST NIGHT AND TODAY AND QUICKLY BRINGS STRATUS AND
DENSE FOG BACK IN BETWEEN 3 AND 6Z SAT. GRIDS NOW REFLECT A RETURN
TO CLOUDY SKIES BY LATE EVENING WITH PATCHY FOG
INITIALLY...EVENTUALLY GOING TO AREAS OF FOG. WHERE FULL CLEARING
HAS TAKEN PLACE...A MENTION OF PATCHY DENSE FREEZING FOG HAS BEEN
ADDED AS TEMPS DROP BELOW FREEZING ACROSS THE AREA AND GREATER
CONCENTRATION OF WATER DROPLETS MAY GIVE A LIGHT GLAZE ON ELEVATED
SURFACES. FOR NOW WILL HOLD OFF ON ANY HEADLINES AND DEFER TO EVE
SHIFT TO MONITOR TRENDS AS COULD END UP MAINLY THE STRATUS ISSUE AND
VSBYS BEHAVE THEMSELVES.
NEXT CHALLENGE WILL BE IF THE STRATUS/FOG CAN LIFT DURING THE DAY
SATURDAY AS INVERSION REMAINS IN PLACE. CLEARING MAY BE HIGHLY
DEPENDENT ON ACTUAL DEPTH OF THE STRATUS DECK. TODAY IT WAS ON
THE THINNER SIDE AND ALLOWED AT LEAST SOME MIXING. THIS MAY NOT BE
THE CASE TOMORROW AS RIDGE AXIS SHIFTS OVERHEAD AND POTENTIALLY
TRAPS THE LOW CLOUDS AND SOME FOG THROUGH THE DAY. FOR NOW WILL
KEEP WITH AT LEAST SOME CLEARING...BUT EXTENSIVE UPDATE CHANGES
MAY BE NEEDED IN LATER FORECASTS. WILL GO WITH GENERAL PERSISTENCE
ON TEMPS AS WELL WITH BUST POTENTIAL MODERATE TO HIGH.
&&
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 300 PM EST FRI DEC 4 2015
LONG TERM PERIOD BEGINS QUIETLY...WITH LARGE SCALE RIDGE AXIS
CENTERED EAST OF THE REGION SUNDAY AND UPPER TROF/CUTOFF LOW
APPROACHING THE REGION FROM THE WEST. CONTINUED WITH A DRY FORECAST
OF 14 POPS OR LESS SUNDAY NIGHT/EARLY MONDAY AS THIS SYSTEM PASSES
THROUGH THE REGION...WITH A BULK OF THE FORCING AND MOISTURE
REMAINING SOUTH OF THE REGION.
A ZONAL FLOW REGIME TAKES HOLD ACROSS THE CONUS THROUGH MUCH OF NEXT
WEEK. THE MAIN FORECAST CHALLENGE WILL BE EMBEDDED SHORTWAVES
TRACKING THROUGH THIS ZONAL FLOW REGIME AND POTENTIAL PRECIPITATION
FOR THE FORECAST AREA. LONG TERM MODEL SOLUTIONS DIFFER WITH THE
HANDLING OF THESE SYSTEMS. WENT WITH A CONSENSUS BLEND APPROACH
WHICH YIELDED SLIGHT CHANCE POPS WEDNESDAY THROUGH THE END OF THE
PERIOD. HONED THESE POPS DOWN TO WEDNESDAY AND WED NIGHT
TIMEFRAME...WHICH QUICK MOVING WAVE TRACKS SOMEWHERE THROUGH THE
REGION...BUT KEPT POPS LESS THAN 20 PERCENT. WENT WITH A CONTINUED
DRY FORECAST THURSDAY AND THURSDAY NIGHT...BUT KEPT THE CONSENSUS
BLEND SOLUTION FOR FRIDAY WITH VERY LOW CHANCE POPS. TOWARD THE END
OF NEXT WEEK...THE OVERALL PATTERN BECOMES MORE AMPLIFIED AS STRONG
EPAC UPPER JET BUCKLES...WITH DEEPER TROUGHING OVER THE WRN CONUS
AND DOWNSTREAM ERN CONUS RIDGING. WHEN THIS ENERGY EJECTS THROUGH
THE REGION SOMETIME TOWARDS THE END OF THE WEEK/NEXT WEEKEND...THIS
WOULD INCREASE PRECIPITATION CHANCES GREATLY. HOWEVER LONG RANGE
MODELS DIFFER GREATLY WITH TIMING/EVOLUTION OF THIS SYSTEM...WHICH
COULD BRING A DECENT RAINFALL TO THE AREA DEPENDING ON THE
EVOLUTION. FOR NOW...WITH STICK WITH THE LOW CHANCE POPS FOR
FRIDAY...BUT THIS WILL BE THE TIME PERIOD TO WATCH FOR THE NEXT
CHANCE OF A DECENT RAINFALL FOR THE REGION.
OTHERWISE...TEMPS THROUGH THE PERIOD WILL BE MILD FOR EARLY/MID
DECEMBER STANDARDS...WITH HIGHS IN THE LOW TO MID 40S SUNDAY THROUGH
TUESDAY...AND MID TO UPPER 40S AND POSSIBLE 50S LATER IN THE PERIOD.
LOW TEMPS THROUGH THE PERIOD WILL START OUT AT OR BELOW FREEZING SAT
NIGHT AND SUN NIGHT...THEN WARMING THROUGH THE 30S EACH NIGHT
THROUGH THE END OF THE PERIOD. THIS WOULD YIELD POTENTIAL AVERAGE
TEMPS NEARLY 10 DEGREES ABOVE NORMAL BY THE END OF THE FORECAST
PERIOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1259 PM EST FRI DEC 4 2015
VFR CONDITIONS HAVE ARRIVED AT KSBN AND SHOULD PERSIST THROUGH AT
LEAST 6Z. CLOUD BASES WERE SLOWLY RISING AT KFWA WITH FULL MIXING
OUT OCCURRING BETWEEN 19 AND 20Z. INCREASING CONCERN FOR FOG
DEVELOPMENT...ESPECIALLY KSBN CLOSER TO SAT MORNING AS MOIST
BOUNDARY LAYER WILL BE IN PLACE WITH IDEAL COOLING SETUP TO ALLOW
FOR PATCHY GROUND FOG. HAVE INTRODUCED A TEMPO GROUP TO KSBN 10 TO
14Z OF MVFR/IFR VSBYS WITH UPPER END MVFR AT KFWA. FURTHER CHANGES
WILL LIKELY BE NEEDED FOR 00Z TAFS.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SYNOPSIS...FISHER
SHORT TERM...FISHER
LONG TERM...NG
AVIATION...FISHER
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AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
314 AM EST FRI DEC 4 2015
.UPDATE...
THE LONG TERM SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
ISSUED AT 310 PM EST THU DEC 3 2015
DRY AND WARMER WEATHER WILL OCCUR THROUGH THE WEEKEND AS HIGH PRESSURE
OVER THE MIDDLE MISSISSIPPI VALLEY MOVES EAST ACROSS THE OHIO VALLEY
LATE TONIGHT AND FRIDAY AND TO SOUTHERN NEW ENGLAND OVER THE WEEKEND.
AN UPPER TROUGH WILL MOVE OUR WAY SUNDAY NIGHT AND MONDAY. BUT AT THE
MOMENT MODELS INDICATE MORE CLOUDS...BUT ONLY SLIGHT CHANCE OF SHOWERS
SOUTH AROUND SUNDAY NIGHT. SLIGHTLY WARMER AND DRY WEATHER WILL OCCUR
NEXT WEEK AS HIGH PRESSURE BUILDS ALONG THE ATLANTIC COAST.
&&
.NEAR TERM /TONIGHT/...
ISSUED AT 1012 PM EST THU DEC 3 2015
THERE WILL BE A SHARP GRADIENT BETWEEN TOTAL CLOUD COVER AND CLEAR
SKIES TONIGHT. HAVE ADJUSTED SKY GRIDS IN LINE WITH HRRR LOW LEVEL
MOISTURE PROGS. CLOUD HAS BEEN TRYING TO ERODE AT THE EDGES ALL
EVENING BUT VERY SLOW TO DO SO. ADJUSTED MIN TEMPS ACCORDINGLY AS
WELL...WITH COOLEST TEMPS LIKELY IN THE SOUTH UNDER CLEAR SKIES.
PREVIOUS DISCUSSION FOLLOWS.
ISSUED AT 310 PM EST THU DEC 3 2015
SATELLITE INDICATES A LARGE AREA OF STRATUS OVER NORTH AND CENTRAL
SECTIONS...WHILE MOSTLY SUNNY SKIES HAVE CONTINUED ACROSS OUR SOUTH.
THE STATUS HAS BEEN CLEARING OVER WESTERN ILLINOIS....WHILE IT HAS
INCREASED A LITTLE ACROSS INDIANA.
EXPECT SOME CLEARING ACROSS ILLINOIS NEXT SEVERAL HOURS. HOWEVER RUC AND
NAM MODEL INDICATES POSSIBLE REDEVELOPMENT OF STRATUS AND FOG OVER
NORTH AND CENTRAL SECTIONS LATER TONIGHT. FOR NOW WILL KEEP SOME STRATUS
OVER NORTH AND CENTRAL SECTIONS OVERNIGHT...WHICH WOULD MINIMIZE THE
THREAT OF FOG. EVEN IF CLOUDS CLEAR...MODELS INDICATE SOME LOW LEVEL
SHEAR WHICH WOULD FAVOR STRATUS OVER FOG. SO FOR NOW WILL LEAVE OUT MENTION
OF FOG AS PARAMETERS ARE VERY IFFY. OVERNIGHT LOWS WILL BE IN THE MIDDLE
TO UPPER 20S WHICH IS CLOSE TO A MOS BLEND.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
ISSUED AT 310 PM EST THU DEC 3 2015
DRY AND WARMER WEATHER WILL OCCUR THIS WEEKEND AS HIGH PRESSURE
MOVES ON TO THE EAST AND MODELS BUILD AN UPPER RIDGE OVER THE
EASTERN U.S. MODEL SOUNDINGS INDICATE MOSTLY CLEAR SKIES THROUGH
SATURDAY NIGHT AND THEN INCREASING CLOUDS SUNDAY AS AN UPPER TROUGH
MOVES OUR WAY.
MOST MODELS KEEP US DRY THROUGH SUNDAY AFTERNOON...WHILE THE EURO
INDICATES TRACE PRECIP AMOUNTS WEST AND SOUTH LATE SUNDAY. WILL GO
WITH CONSENSUS AND KEEP EVERYTHING DRY THROUGH SUNDAY. HIGHS WILL
BE IN THE UPPER 40S TO LOWER 50S FRIDAY AND SUNDAY AND IN THE LOWER
TO MIDDLE 50S SATURDAY. LOWS WILL BE IN THE UPPER 20S TO AROUND 30
FRIDAY NIGHT AND IN THE LOWER 30S SATURDAY NIGHT. WENT SLIGHTLY ABOVE
A MOS BLEND ON HIGHS WITH SOME SUN AND WARM ADVECTION. OTHERWISE...STAYED
CLOSE TO A MOS BLEND ON LOWS.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
ISSUED AT 314 AM EST FRI DEC 4 2015
UPPER LEVEL FLOW WILL REMAIN QUASI-ZONAL THROUGHOUT MUCH OF NEXT
WEEK...WITH MILD AND MAINLY DRY WEATHER CONTINUING. OVERALL MODEL
GUIDANCE EXHIBITING POOR RUN TO RUN CONSENSUS AS A FEW WEAK WAVES
ALOFT EJECT OUT OF THE UPPER ENERGY MOVING INTO THE PACIFIC
NORTHWEST. PLENTY OF UNCERTAINTY ON HOW AND IF THESE WAVES WILL
IMPACT WEATHER ACROSS THE REGION WHICH RESULTS IN A LOW
CONFIDENCE FORECAST FOR THE EXTENDED PERIOD AT THIS TIME.
WEAK DISTURBANCE ALOFT PASSING THROUGH THE OHIO VALLEY SUNDAY
NIGHT WILL BE MOVING AWAY TO THE EAST ON MONDAY WITH ANY LIGHT
PRECIPITATION DEPARTING WITH IT. MODEL SOUNDINGS AND RH PROGS
SUGGESTIVE OF LINGERING CLOUDS FOR MONDAY IN WAKE OF THE SYSTEM.
SURFACE HIGH PRESSURE WILL RETURN THROUGH MIDWEEK WITH PARTLY
CLOUDY SKIES. SOME HINTS OF AN UPPER WAVE PASSING THROUGH THE
LOWER GREAT LAKES AND OHIO VALLEY WEDNESDAY INTO THURSDAY BUT AS
MENTIONED ABOVE...OPERATIONAL RUNS ARE OUT OF SYNC WITH LITTLE
SUPPORT FROM THE INDIVIDUAL ENSEMBLE MEMBERS. WILL MAINTAIN DRY
CONDITIONS THROUGH THURSDAY AS A RESULT AND CONTINUE TO MONITOR.
EASTWARD PROGRESSION OF A BROAD UPPER TROUGH INTO THE CENTRAL U S
BY NEXT WEEKEND AS ENERGY ALOFT PUSHES ONTO THE WEST COAST LENDS
TO HIGHER CONFIDENCE IN A MORE ACTIVE WEATHER PATTERN COMMENCING
ACROSS THE REGION BEYOND THE 7 DAY PERIOD NEXT WEEKEND INTO THE
FOLLOWING WEEK. CERTAINLY SOMETHING TO WATCH OVER THE NEXT SEVERAL
DAYS.
&&
.AVIATION /DISCUSSION FOR THE 040900Z TAF UPDATE/...
ISSUED AT 314 AM EST FRI DEC 4 2015
STRATUS HAS EXPANDED BACK SOUTHEAST ACROSS THE REGION EARLY THIS
MORNING AS ANTICIPATED. EXPECT ALL SITES TO BE IMPACTED THROUGH
DAYBREAK WITH A SHALLOW BUT SHARP INVERSION NOTED ON MODEL
SOUNDINGS TO LINGER INTO MID MORNING. LOWERED CEILINGS TO CLOSER
TO 500FT BASED ON CURRENT OBS AND DELAYED SCATTERING OF CLOUDS
UNTIL AFTER DAYBREAK AT ALL SITES. WILL CONTINUE TO MONITOR BUT
NOT OUT OF THE QUESTION THAT MAY NEED DELAY CLOUD SCATTERING EVEN
FURTHER FOR 12Z TAFS.
06Z DISCUSSION FOLLOWS.
LATEST SATELLITE LOOP INDICATES AREA OF CEILINGS 008 AGL-015 OVER PARTS OF
NORTHERN AND CENTRAL INDIANA IS BEGINNING TO EXPAND AGAIN DUE TO NOCTURNAL
COOLING AND A STOUT INVERSION BELOW 015 AS SEEN ON THIS EVENING/S UPPER AIR.
AS A RESULT...IT APPEARS DOUBTFUL THESE CEILINGS WILL SCATTER OUT BEFORE
SUNRISE AND MAY LINGER WELL INTO THE DAYLIGHT HOURS ON FRIDAY. WILL BRING
IFR CEILINGS TO ALL THE TAF SITES BY 040800Z AND SCATTER THEM OUT FROM
SOUTHWEST TO NORTHEAST AFTER SUNRISE.
DUE TO THE CLOUD COVER...DO NOT THINK VISIBILITIES WILL GET TOO OUT OF
HAND...BUT MAY SEE SOME IFR VISIBILITY RESTRICTIONS IN THE KBMG AREA
FOR A PERIOD BEFORE THE LOW CEILINGS ADVECT IN.
SURFACE WINDS AT OR BELOW 7 KTS THROUGH 041800Z.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...JH
NEAR TERM...JH/NIELD
SHORT TERM...JH
LONG TERM....RYAN
AVIATION...JAS/RYAN
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1131 PM EST THU DEC 3 2015
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 310 PM EST THU DEC 3 2015
DRY AND WARMER WEATHER WILL OCCUR THROUGH THE WEEKEND AS HIGH PRESSURE
OVER THE MIDDLE MISSISSIPPI VALLEY MOVES EAST ACROSS THE OHIO VALLEY
LATE TONIGHT AND FRIDAY AND TO SOUTHERN NEW ENGLAND OVER THE WEEKEND.
AN UPPER TROUGH WILL MOVE OUR WAY SUNDAY NIGHT AND MONDAY. BUT AT THE
MOMENT MODELS INDICATE MORE CLOUDS...BUT ONLY SLIGHT CHANCE OF SHOWERS
SOUTH AROUND SUNDAY NIGHT. SLIGHTLY WARMER AND DRY WEATHER WILL OCCUR
NEXT WEEK AS HIGH PRESSURE BUILDS ALONG THE ATLANTIC COAST.
&&
.NEAR TERM /TONIGHT/...
ISSUED AT 1012 PM EST THU DEC 3 2015
THERE WILL BE A SHARP GRADIENT BETWEEN TOTAL CLOUD COVER AND CLEAR
SKIES TONIGHT. HAVE ADJUSTED SKY GRIDS IN LINE WITH HRRR LOW LEVEL
MOISTURE PROGS. CLOUD HAS BEEN TRYING TO ERODE AT THE EDGES ALL
EVENING BUT VERY SLOW TO DO SO. ADJUSTED MIN TEMPS ACCORDINGLY AS
WELL...WITH COOLEST TEMPS LIKELY IN THE SOUTH UNDER CLEAR SKIES.
PREVIOUS DISCUSSION FOLLOWS.
ISSUED AT 310 PM EST THU DEC 3 2015
SATELLITE INDICATES A LARGE AREA OF STRATUS OVER NORTH AND CENTRAL
SECTIONS...WHILE MOSTLY SUNNY SKIES HAVE CONTINUED ACROSS OUR SOUTH.
THE STATUS HAS BEEN CLEARING OVER WESTERN ILLINOIS....WHILE IT HAS
INCREASED A LITTLE ACROSS INDIANA.
EXPECT SOME CLEARING ACROSS ILLINOIS NEXT SEVERAL HOURS. HOWEVER RUC AND
NAM MODEL INDICATES POSSIBLE REDEVELOPMENT OF STRATUS AND FOG OVER
NORTH AND CENTRAL SECTIONS LATER TONIGHT. FOR NOW WILL KEEP SOME STRATUS
OVER NORTH AND CENTRAL SECTIONS OVERNIGHT...WHICH WOULD MINIMIZE THE
THREAT OF FOG. EVEN IF CLOUDS CLEAR...MODELS INDICATE SOME LOW LEVEL
SHEAR WHICH WOULD FAVOR STRATUS OVER FOG. SO FOR NOW WILL LEAVE OUT MENTION
OF FOG AS PARAMETERS ARE VERY IFFY. OVERNIGHT LOWS WILL BE IN THE MIDDLE
TO UPPER 20S WHICH IS CLOSE TO A MOS BLEND.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
ISSUED AT 310 PM EST THU DEC 3 2015
DRY AND WARMER WEATHER WILL OCCUR THIS WEEKEND AS HIGH PRESSURE
MOVES ON TO THE EAST AND MODELS BUILD AN UPPER RIDGE OVER THE
EASTERN U.S. MODEL SOUNDINGS INDICATE MOSTLY CLEAR SKIES THROUGH
SATURDAY NIGHT AND THEN INCREASING CLOUDS SUNDAY AS AN UPPER TROUGH
MOVES OUR WAY.
MOST MODELS KEEP US DRY THROUGH SUNDAY AFTERNOON...WHILE THE EURO
INDICATES TRACE PRECIP AMOUNTS WEST AND SOUTH LATE SUNDAY. WILL GO
WITH CONSENSUS AND KEEP EVERYTHING DRY THROUGH SUNDAY. HIGHS WILL
BE IN THE UPPER 40S TO LOWER 50S FRIDAY AND SUNDAY AND IN THE LOWER
TO MIDDLE 50S SATURDAY. LOWS WILL BE IN THE UPPER 20S TO AROUND 30
FRIDAY NIGHT AND IN THE LOWER 30S SATURDAY NIGHT. WENT SLIGHTLY ABOVE
A MOS BLEND ON HIGHS WITH SOME SUN AND WARM ADVECTION. OTHERWISE...STAYED
CLOSE TO A MOS BLEND ON LOWS.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
ISSUED AT 240 PM EST THU DEC 3 2015
ENSEMBLES BRING AN UPPER WAVE ACROSS THE AREA SUNDAY NIGHT AS A WEAK
SURFACE SYSTEM SLIDES EAST ACROSS THE TENNESSEE VALLEY. MOISTURE
WILL BE LIMITED...HOWEVER THE FORCING IS ENOUGH TO CONTINUE TO CARRY
WEAK CHANCES OF RAIN SHOWERS ACROSS THE SOUTHERN TIER.
WEAK RIDGING WILL PREVAIL THROUGHOUT MOST OF THE EXTENDED WITH DRY
CONDITIONS AND WARMER THAN NORMAL TEMPERATURES THROUGHOUT NEXT
WEEK.
&&
.AVIATION /DISCUSSION FOR THE 040600Z TAFS/...
ISSUED AT 1131 PM EST THU DEC 3 2015
LATEST SATELLITE LOOP INDICATES AREA OF CEILINGS 008 AGL-015 OVER PARTS OF
NORTHERN AND CENTRAL INDIANA IS BEGINNING TO EXPAND AGAIN DUE TO NOCTURNAL
COOLING AND A STOUT INVERSION BELOW 015 AS SEEN ON THIS EVENING/S UPPER AIR.
AS A RESULT...IT APPEARS DOUBTFUL THESE CEILINGS WILL SCATTER OUT BEFORE
SUNRISE AND MAY LINGER WELL INTO THE DAYLIGHT HOURS ON FRIDAY. WILL BRING
IFR CEILINGS TO ALL THE TAF SITES BY 040800Z AND SCATTER THEM OUT FROM
SOUTHWEST TO NORTHEAST AFTER SUNRISE.
DUE TO THE CLOUD COVER...DO NOT THINK VISIBILITIES WILL GET TOO OUT OF
HAND...BUT MAY SEE SOME IFR VISIBILITY RESTRICTIONS IN THE KBMG AREA
FOR A PERIOD BEFORE THE LOW CEILINGS ADVECT IN.
SURFACE WINDS AT OR BELOW 7 KTS THROUGH 041800Z.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...JH
NEAR TERM...JH/NIELD
SHORT TERM...JH
LONG TERM...SMF
AVIATION...JAS
AREA FORECAST DISCUSSION
National Weather Service Paducah KY
220 PM CST FRI DEC 4 2015
.SHORT TERM...(This evening through Sunday)
Issued at 206 PM CST FRI DEC 4 2015
Once again today, there is a strong subsidence inversion just off
the surface, keeping this morning`s fog/low stratus trapped
beneath 1000 FT AGL. This area had shriveled northward by mid
morning, where it has remained nearly stationary thru the
day...just barely beyond our northern CWA border. Differential
heating right along its southern extent has eaten away at it
gradually in the last hour or two...and may preclude its sag back
into the FA tonight, as temps even on our northern periphery have
bounded upwards closer to the rest of the FA. Even so, that area
will need to be closely monitored, in case our northern tier
counties end up having it develop again.
The center of the surface high shifts eastward tonight and light
selys at and just off the surface will hopefully preclude that
from happening. Still anticipate another cool night, with lows
again at or just below climo (u20s/nr 30).
More robust warm air advection will begin tmrw, and continue thru
the weekend. It will take awhile to warm (and moisten) the dry
atmos column, so most of the weekend should remain dry, as temps
rebound into/thru the 50s/30s for highs/lows.
.LONG TERM...(Sunday night through Friday)
Issued at 206 PM CST FRI DEC 4 2015
A minor mid level shrtwv/closed low is progged by the models to be
moving through the PAH forecast area Sun night. Moist return flow
will be very limited with this system, but there will be at least
the passage of a sfc cold front with it, triggering light amounts of
rain mainly east of the MS river. The probability for actual
measurable pcpn remains quite low. The disturbance should be out of
our region after 12Z Mon.
The Pacific train of low-amplitude shrtwvs will apparently continue
through most of the week. Another impulse and sfc front may affect
the region Wed, and again on Fri. The timing of these impulses is
quite variable among the med range models, especially for day 6 and
7. For now, we will go with a forecast of a couple of low PoP, low
QFP rain events, with partly cloudy and relatively mild conditions
in between, especially toward Day 7. In fact, just beyond Day 7, the
ECENES/GEFS are beginning to suggest a change to the recent pattern
aloft, to a longwave trof west/ridge east, which would promote
warmer swrly flow aloft for our region.
&&
.AVIATION...
Issued at 206 PM CST FRI DEC 4 2015
Strong subsidence inversion precludes parcels uvm above 1000 FT
AGL, so SKC abounds. Nearby, do see trapped morning fogs/low
stratus beneath said inversion, and will have to watch this area
closely in case it sags southward down the Wabash valley and
impacts KEVV (or KOWB). For now, will just hit a little MVFR late
night fog all terminals as depression temps close. Otherwise
little to note in light wind regime with surface high slowly
nudging to the east with time.
&&
.PAH Watches/Warnings/Advisories...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
Area Forecast Discussion
National Weather Service Louisville KY
254 PM EST FRI DEC 4 2015
.SHORT TERM (Now through Sunday)...
Issued at 245 PM EST Fri Dec 4 2015
Main short-term challenge is the extent and impact of potential
freezing fog late tonight into Sat morning. This morning saw quite a
bit of fog, with most of the valleys finally breaking out just
before midday while a more extensive area of stratus/fog held on in
our northernmost counties in southern Indiana.
Thinking is that we will see a repeat of the valley fog late
tonight, but a few factors weigh against any expansion onto the
higher/flatter terrain even though winds will be light and RH fields
could support a "sunrise surprise." Strong surface high draped
across northern Kentucky and southern Indiana/Ohio will start
retreating to the east, establishing a light easterly low-level
flow. This carries a slight downslope component, and should limit
fog to just the more sheltered areas. Also we are finally starting
to see some thin spots in the stratus over central Indiana and
western Ohio, and guidance suggests these clouds will dissipate in
the evening when the easterly flow sets up. Therefore will limit the
mention of fog to the valleys, but where it does occur freezing fog
will be a concern. Will highlight that in the HWO, and let later
shifts hone in on where the real problem areas will be.
Once the valley fog dissipates Sat morning, it looks like an
unusually pleasant December weekend with seasonable temps and quite
a bit of sunshine. Temps should run just above climo by day and just
below by night. Max temp forecasts favored the GFS MOS, with
Saturday just a bit milder than Sunday out of respect for the cloud
shield that will arrive Sunday afternoon ahead of the next system.
Sat night min temp forecast is below guidance, as it still looks
favorable for radiational cooling, and the long night should still
allow a sharp and shallow inversion to develop underneath the weak
return flow.
.LONG TERM (Sunday night through Friday)...
Issued at 245 PM EST Fri Dec 4 2015
Progressive pattern will remain in place for much of next week, with
a series of closed upper lows rolling through. First system comes
through Sunday night and Monday, and without any opportunity for the
Gulf to open up, it looks like a low-POP, low-QPF scenario. Not much
change to the going forecast there, and daytime temps are knocked
back a couple degrees to climo.
Flat pattern Monday night through Tuesday night will amplify again
on Wednesday, with the next upper low closing off as it swings
through the Ohio Valley. This system draws enough moisture northward
to support low chance POPs. Will keep QPF low for now, but the ECMWF
is the more bullish of the models here and could provide a decent
shot of rain if it verifies.
By Friday yet another upper trof will be headed our way, this time a
southern stream system lifting out of the Desert Southwest. Not
confident enough in the timing to go any higher than chance POPs for
Friday, but when this system does come through, higher POPs and
higher QPF will be warranted as it could start to take on enough of
a negative tilt to tap into better moisture. Still expect the main
impact of this system to be beyond the scope of this 7-day forecast.
&&
.AVIATION (18Z TAF Update)...
Updated at 1210 PM EST Fri Dec 4 2015
Tougher forecast for tonight than would appear given that 99% of the
troposphere looks dry. Cigs over a lot of Indiana are in the
LIFR/VLIFR range still this morning. HRRR did a better job with
these clouds overnight and it now is calling for a southward
expansion of those clouds in patches over central Kentucky. The
patchy nature makes it hard to go all out over the terminals
tonight. For now will go with few-sct very low deck and some
reduction in vsby toward daybreak, but cannot rule out much worse
conditions. Will amend as more hi-res near-term guidance comes in.
&&
.LMK Watches/Warnings/Advisories...
KY...NONE.
IN...NONE.
&&
$$
Short Term........RAS
Long Term.........RAS
Aviation..........RJS
AREA FORECAST DISCUSSION
NWS JACKSON KY
1220 PM EST FRI DEC 4 2015
.UPDATE...
ISSUED AT 1132 AM EST FRI DEC 4 2015
VIS SAT NOW SHOWING THAT MOST OF THE RIVER VALLEY FOG HAS CLEARED
OUT THIS LATE MORNING HOUR. THEREFORE WILL UPDATE THE
NDFD GRIDS...ZFP...AND HWO TO REFLECT THIS THOUGHT. OTHERWISE
JUST SOME MINOR TWEAKS TO LATEST OBS AND TRENDS.
UPDATE ISSUED AT 958 AM EST FRI DEC 4 2015
VIS SAT CONTINUES TO SHOW RIVER VALLEY FOG...WHICH GIVEN THE TEMPS
THIS MORNING WILL LIKELY BE FREEZING FOG. NO ISSUES ROAD WISE ARE
EXPECTED THIS MORNING. THIS VALLEY FOG WILL CONTINUE TO DISSIPATE
THROUGH THE MORNING HOURS. UPDATED GRIDS TO REFLECT VALLEY FOG
LOCATIONS...OTHERWISE NOT MAJOR CHANGES NEEDED THIS UPDATE. DID
OPT TO UPDATE THE TEMP...DEWS... AND WINDS WITH LATEST OBS AND
TRENDS. GRIDS HAVE BEEN SENT TO NDFD.
UPDATE ISSUED AT 727 AM EST FRI DEC 4 2015
SINCE ALL TEMPERATURES ACROSS THE REGION ARE BELOW FREEZING...IT
IS LIKELY THAT WHATEVER PATCHY FOG HAS DEVELOPED ACROSS THE REGION
IS OF THE FREEZING VARIETY. AS SUCH...CHANGED WEATHER GRIDS FOR
THE NEXT COUPLE HOURS TO REFLECT PATCHY FREEZING FOG INSTEAD.
ALSO HIGHLIGHTED POTENTIAL IMPACTS IN THE HWO. HOWEVER...GIVEN THE
PATCHY NATURE OF THE FOG AND WITH LITTLE TO NO IMPACTS REPORTED
THUS FAR...DID NOT ISSUE ANY FURTHER PRODUCTS. MOST REPORTS THIS
MORNING HAVE BEEN FOR FROST RATHER THAN FOG. REGARDLESS...ANY
REMAINING FOG SHOULD BURN OFF OVER THE NEXT HOUR OR TWO AS WE
CONTINUE TO WARM UP. LOADED IN THE LATEST OBSERVATIONS TO MAKE
SURE THE NEAR TERM FORECAST WAS WELL ON TRACK WITH THE CURRENT
CONDITIONS. A NEW FORECAST PACKAGE WAS SENT OUT TO REFLECT THE
CHANGES IN FOG WORDING. ALL GRIDS WERE PUBLISHED AND SENT TO
NDFD/WEB.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 242 AM EST FRI DEC 4 2015
HIGH PRESSURE IS CURRENTLY DIRECTLY OVERHEAD THE STATE OF KENTUCKY
AS OF 7Z. THIS IS PROVIDING LIGHT WINDS AND STRONG SUBSIDENCE DURING
THE OVERNIGHT HOURS. WENT AHEAD AND LOWERED SOME OF THE DEEPER
VALLEY LOCATIONS LOW TEMPERATURES FOR EARLY THIS MORNING GIVEN THE
CURRENT OBSERVATIONS.
OTHERWISE...EXPECT QUIET AND CLEAR CONDITIONS THROUGH THE DURATION
OF THE SHORT TERM PERIOD AS THE HIGH PRESSURE REMAINS OVERHEAD.
AFTERNOON TEMPERATURES WILL CONTINUE TO SHOW AN INCREASING
TREND...WITH HIGHS TODAY TOPPING OUT AROUND THE 50 DEGREE
MARK...THEN CLIMBING TO THE MID TO UPPER 50S BY TOMORROW. STRONG
SUBSIDENCE AND MAXIMUM RADIATIONAL COOLING OVERNIGHT TONIGHT WILL
PROMOTE ANOTHER RIDGE VALLEY SPLIT AND SIGNIFICANT DIURNAL
DROPS...WITH UPPER 20S TO AROUND 30 EXPECTED ON THE RIDGES FOR
LOWS...AND LOW TO MID 20S IN THE VALLEYS.
THE ONE CONCERN DURING THIS FORECAST PERIOD WILL BE THE AMOUNT OF
DRY AIR BEING USHERED INTO THE REGION UNDER THE INFLUENCE OF THIS
HIGH PRESSURE SYSTEM. THIS WILL CREATE LOW DEW POINTS AND LOW RH
SITUATIONS BOTH THIS AFTERNOON...AND EVEN MORE SO SATURDAY
AFTERNOON. LUCKILY...WINDS WILL BE LIGHT AND PREVIOUS DAYS RAINS
WILL HELP TO MITIGATE SOME OF THE FIRE CONCERNS...BUT THIS WILL
CONTINUE TO BE SOMETHING TO MONITOR THROUGH THE UPCOMING WEEKEND.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 458 AM EST FRI DEC 4 2015
THE EXTENDED PERIOD WILL START OUT DRY AND PLEASANT...WITH ABOVE
NORMAL TEMPERATURES EXPECTED DURING THE DAY ON SUNDAY.
HOWEVER...CONDITIONS WILL START OUT QUITE COLD ACROSS THE AREA ON
SUNDAY MORNING...WITH LOWS DROPPING INTO THE LOW TO MID 20S IN OUR
VALLEYS...WHILE THE SURROUNDING RIDGES ONLY FALL INTO THE LOW TO
MID 30S. THE WEATHER IS EXPECTED TO REMAIN DRY THROUGH EARLY
MONDAY EVENING. AFTER MONDAY EVENING...HOWEVER...THE MODEL DATA
BEGINS TO DIVERGE...LEAVING US WITH AN UNCERTAIN FORECAST FROM
MONDAY NIGHT ONWARD. FOR NOW...WITH THE MODELS SHOWING A SERIES OF
FAST MOVING SHORT WAVES EJECTING OUT OF THE PLAINS AND ACROSS THE
EASTERN THIRD OF THE CONUS...DECIDED TO GO WITH LOW PRECIPITATION
CHANCES SUNDAY NIGHT THROUGH LATE MONDAY NIGHT. AFTER ANOTHER
POSSIBLE DRY PERIOD TUESDAY AND TUESDAY NIGHT...INTRODUCED MORE
RAIN CHANCES WEDNESDAY THROUGH THURSDAY...AS THE ECMWF MODEL TRIES
TO BRING A FAIRLY WELL DEVELOPED AREA OF LOW PRESSURE OUT OF THE
PLAINS AND ACROSS THE UPPER MISSISSIPPI VALLEY AND GREAT LAKES
REGIONS. THE SURFACE FRONT THAT WOULD BE ASSOCIATED WITH THIS
UPPER LOW WOULD WHAT WOULD BRING RAINFALL TO OUR AREA.
HOWEVER...THE GFS MODEL IS DRY FOR THURSDAY...WHEN THE ECMWF HAS
AN AREA OF RAINFALL AFFECTING THE AREA. WITH THAT IN MIND...WENT
WITH ONLY A SLIGHT CHANCE OF RAIN ACROSS EASTERN KENTUCKY FOR THE
WEDNESDAY THURSDAY TIME FRAME.
TEMPERATURES ACROSS THE AREA ARE EXPECTED TO BE GENERALLY ABOVE
NORMAL THROUGH OUT THE PERIOD...WITH DAY TIME HIGHS IN THE MID TO
UPPER 50S AND OVERNIGHT LOWS IN THE MID TO UPPER 30S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1220 PM EST FRI DEC 4 2015
HIGH PRESSURE IS LEADING TO VFR CONDITIONS ACROSS THE REGION THIS
AFTERNOON. THIS IS EXPECTED TO BE THE STORY FOR THE TAF PERIOD IN
GENERAL. THIS MORNING WE HAD A FEW INSTANCES OF MAINLY RIVER
VALLEY FREEZING FOG...SOUNDINGS DO SUGGEST A SOME LOW LEVEL
MOISTURE ON SATURDAY MORNING. RIGHT NOW NOT CONFIDENT THIS WILL
MAKE IT INTO ANY OF THE TAF SITES...SO HAVE OPTED NOT TO INCLUDE
IN THIS TAF CYCLE. THIS SURFACE HIGH PRESSURE IS ALSO INTRODUCING
LIGHT AND VARIABLE WINDS.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...DJ
SHORT TERM...JMW
LONG TERM...AR
AVIATION...DJ
Area Forecast Discussion
National Weather Service Louisville KY
1209 PM EST FRI DEC 4 2015
...Updated Aviation Discussion...
...Forecast Update...
Issued at 1055 AM Fri Dec 4 2015
Fog is finally dissipating in a lot of the valleys, but the more
extensive area of fog/stratus over Indiana is going nowhere fast.
Have updated products to remove the fog mention, except over our
northernmost counties in southern Indiana, where the clouds/fog will
hang on for much of the afternoon. Temps are just warm enough that
in daylight conditions, freezing fog should not be as much of an
issue as it had been earlier. Therefore will just keep it plain old
fog. Have clipped max temps by several degrees where the clouds and
fog remain, but if it`s persistent enough, even the mid 40s in the
revised forecast may be too generous. Still on track for around 50
elsewhere.
Issued at 925 AM Fri Dec 4 2015
Patchy freezing fog is mostly dissipating based on latest METARs and
area webcams. Still seeing some of the deeper river valleys pretty
well socked in, so will take a bit slower approach to removing the
early fog wording from the ZFP. A more extensive area of fog/stratus
sits over Indiana just north of our CWA boundary, and I have little
confidence that it will go anywhere given poor mixing under a 1037mb
high pressure, and low December sun angle. That said, the current
forecast should be pretty well on track, so will just refresh to
pull the fog wording as the valleys finally start to mix a bit, and
will keep an eye on whether the stratus deck tries to creep into our
Indiana counties.
.SHORT TERM (Now through Saturday)...
Issued at 300 AM EST Fri Dec 4 2015
In the near term, high pressure will drift overhead early this
morning and then move slowly eastward during the day today. IR
satellite imagery reveals clear skies across the region. A decent
ridge/valley decoupling has taken place with the cooler valleys
presently sitting in the mid 20s with upper 20s to around 30
elsewhere. Dry air is abundant aloft across the region. However,
we do have some low-level moisture down near the surface which may
result in some areas of freezing fog this morning. The best chances
for the fog look to be across our southern Indiana counties and in
the KY river valley region of central KY. Temperatures may cool a
few more degrees before sunrise with most locations seeing readings
in the low-mid 20s in the valleys and in the mid-upper 20s elsewhere.
For Today through Saturday, quiet weather is expected as high
pressure will continue to dominance our weather pattern. Highs this
afternoon will warm into the upper 40s to around 50 in the north
with lower 50s likely across southern KY. Another cool night looks
likely tonight with lows in the valleys cooling into the lower-mid
20s with mid-upper 20s elsewhere. We will pick up a bit more
southerly flow on Saturday with mostly sunny skies. Temperatures
look to warm into the lower 50s in the north with low-mid 50s across
the south.
.LONG TERM (Saturday Night through Thursday)...
Issued at 323 AM EST Fri Dec 4 2015
In the long term period, a progressive flow will remain in place
aloft with a series of compact upper level lows rolling from east to
west across the CONUS. The first of these will transverse our
region late Sunday and into the day on Monday. Moisture is not all
that plentiful with the system as return flow from the Gulf will not
have sufficient time to moisten up the column. However, model time-
height cross sections do suggest plenty of mid-high level cloud
cover to push through with this system. Ascent is not overly
strong, but forcing with the upper low (mainly due to steep lapse
rates) look to be enough to continue low chance PoPs in the Sunday
night/Monday time frame.
The upper flow will then flatten back out by Tuesday, only to re-
amplify as the next upper level low crosses the region Wednesday
night into Thursday as it ejects from the northern Plains. Again,
large scale ascent with this system is not overly impressive, but
enough moisture and lift look available to warrant low chance PoPs
in the Wed night/Thursday time frame...despite the blended guidance
being a little more optimistic on dry conditions.
Temperatures through the period look to run a little above seasonal
normals. Typical early December highs average in the upper 40s. The
latest guidance suggests daily highs in the lower to middle 50s with
overnight lows in the mid-upper 30s. The warmest day looks to be
Thursday where some upper 50s across the south will be possible.
Overall, not much in the way of change from the previous forecast.
Looking further out, a more active weather pattern looks to take
shape as we head into late next week and into the mid part of
December. Latest teleconnection pattern suggest a
+AO/+NAO/+PNA/+EPO pattern in place by late next week. These
indices would support the series of rolling upper level lows across
the CONUS. However, as we head down the road, the models suggest a
downward trend in all the indices as we head toward mid-month. As
this downward trend occurs, we`re likely to see an active weather
pattern set up across the central US and eventually into the Ohio
Valley.
Initially, we`ll be on the warm side of the pattern with the threat
of additional heavy rainfall and milder than normal temperatures. As
the indices slide toward the neutral/negative range, we`ll
gradually see the sensible weather catch up with a more seasonal
cold pattern emerging after mid-month. It should be noted that the
long term models have struggled with timing of the downtrend in the
teleconnection indices. Past verification shows that they tend to
drop the indices too quick...so it would not be surprising to see
the eventual return to seasonal cold to be delayed slightly in later
forecasts.
&&
.AVIATION (18Z TAF Update)...
Updated at 1210 PM EST Fri Dec 4 2015
Tougher forecast for tonight than would appear given that 99% of the
troposphere looks dry. Cigs over a lot of Indiana are in the
LIFR/VLIFR range still this morning. HRRR did a better job with
these clouds overnight and it now is calling for a southward
expansion of those clouds in patches over central Kentucky. The
patchy nature makes it hard to go all out over the terminals
tonight. For now will go with few-sct very low deck and some
reduction in vsby toward daybreak, but cannot rule out much worse
conditions. Will amend as more hi-res near-term guidance comes in.
&&
.LMK Watches/Warnings/Advisories...
KY...NONE.
IN...NONE.
&&
$$
Update.........RAS
Short Term.....MJ
Long Term......MJ
Aviation.......RJS
AREA FORECAST DISCUSSION
NWS JACKSON KY
1132 AM EST FRI DEC 4 2015
.UPDATE...
ISSUED AT 1132 AM EST FRI DEC 4 2015
VIS SAT NOW SHOWING THAT MOST OF THE RIVER VALLEY FOG HAS CLEARED
OUT THIS LATE MORNING HOUR. THEREFORE WILL UPDATE THE
NDFD GRIDS...ZFP...AND HWO TO REFLECT THIS THOUGHT. OTHERWISE
JUST SOME MINOR TWEAKS TO LATEST OBS AND TRENDS.
UPDATE ISSUED AT 958 AM EST FRI DEC 4 2015
VIS SAT CONTINUES TO SHOW RIVER VALLEY FOG...WHICH GIVEN THE TEMPS
THIS MORNING WILL LIKELY BE FREEZING FOG. NO ISSUES ROAD WISE ARE
EXPECTED THIS MORNING. THIS VALLEY FOG WILL CONTINUE TO DISSIPATE
THROUGH THE MORNING HOURS. UPDATED GRIDS TO REFLECT VALLEY FOG
LOCATIONS...OTHERWISE NOT MAJOR CHANGES NEEDED THIS UPDATE. DID
OPT TO UPDATE THE TEMP...DEWS... AND WINDS WITH LATEST OBS AND
TRENDS. GRIDS HAVE BEEN SENT TO NDFD.
UPDATE ISSUED AT 727 AM EST FRI DEC 4 2015
SINCE ALL TEMPERATURES ACROSS THE REGION ARE BELOW FREEZING...IT
IS LIKELY THAT WHATEVER PATCHY FOG HAS DEVELOPED ACROSS THE REGION
IS OF THE FREEZING VARIETY. AS SUCH...CHANGED WEATHER GRIDS FOR
THE NEXT COUPLE HOURS TO REFLECT PATCHY FREEZING FOG INSTEAD.
ALSO HIGHLIGHTED POTENTIAL IMPACTS IN THE HWO. HOWEVER...GIVEN THE
PATCHY NATURE OF THE FOG AND WITH LITTLE TO NO IMPACTS REPORTED
THUS FAR...DID NOT ISSUE ANY FURTHER PRODUCTS. MOST REPORTS THIS
MORNING HAVE BEEN FOR FROST RATHER THAN FOG. REGARDLESS...ANY
REMAINING FOG SHOULD BURN OFF OVER THE NEXT HOUR OR TWO AS WE
CONTINUE TO WARM UP. LOADED IN THE LATEST OBSERVATIONS TO MAKE
SURE THE NEAR TERM FORECAST WAS WELL ON TRACK WITH THE CURRENT
CONDITIONS. A NEW FORECAST PACKAGE WAS SENT OUT TO REFLECT THE
CHANGES IN FOG WORDING. ALL GRIDS WERE PUBLISHED AND SENT TO
NDFD/WEB.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 242 AM EST FRI DEC 4 2015
HIGH PRESSURE IS CURRENTLY DIRECTLY OVERHEAD THE STATE OF KENTUCKY
AS OF 7Z. THIS IS PROVIDING LIGHT WINDS AND STRONG SUBSIDENCE DURING
THE OVERNIGHT HOURS. WENT AHEAD AND LOWERED SOME OF THE DEEPER
VALLEY LOCATIONS LOW TEMPERATURES FOR EARLY THIS MORNING GIVEN THE
CURRENT OBSERVATIONS.
OTHERWISE...EXPECT QUIET AND CLEAR CONDITIONS THROUGH THE DURATION
OF THE SHORT TERM PERIOD AS THE HIGH PRESSURE REMAINS OVERHEAD.
AFTERNOON TEMPERATURES WILL CONTINUE TO SHOW AN INCREASING
TREND...WITH HIGHS TODAY TOPPING OUT AROUND THE 50 DEGREE
MARK...THEN CLIMBING TO THE MID TO UPPER 50S BY TOMORROW. STRONG
SUBSIDENCE AND MAXIMUM RADIATIONAL COOLING OVERNIGHT TONIGHT WILL
PROMOTE ANOTHER RIDGE VALLEY SPLIT AND SIGNIFICANT DIURNAL
DROPS...WITH UPPER 20S TO AROUND 30 EXPECTED ON THE RIDGES FOR
LOWS...AND LOW TO MID 20S IN THE VALLEYS.
THE ONE CONCERN DURING THIS FORECAST PERIOD WILL BE THE AMOUNT OF
DRY AIR BEING USHERED INTO THE REGION UNDER THE INFLUENCE OF THIS
HIGH PRESSURE SYSTEM. THIS WILL CREATE LOW DEW POINTS AND LOW RH
SITUATIONS BOTH THIS AFTERNOON...AND EVEN MORE SO SATURDAY
AFTERNOON. LUCKILY...WINDS WILL BE LIGHT AND PREVIOUS DAYS RAINS
WILL HELP TO MITIGATE SOME OF THE FIRE CONCERNS...BUT THIS WILL
CONTINUE TO BE SOMETHING TO MONITOR THROUGH THE UPCOMING WEEKEND.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 458 AM EST FRI DEC 4 2015
THE EXTENDED PERIOD WILL START OUT DRY AND PLEASANT...WITH ABOVE
NORMAL TEMPERATURES EXPECTED DURING THE DAY ON SUNDAY.
HOWEVER...CONDITIONS WILL START OUT QUITE COLD ACROSS THE AREA ON
SUNDAY MORNING...WITH LOWS DROPPING INTO THE LOW TO MID 20S IN OUR
VALLEYS...WHILE THE SURROUNDING RIDGES ONLY FALL INTO THE LOW TO
MID 30S. THE WEATHER IS EXPECTED TO REMAIN DRY THROUGH EARLY
MONDAY EVENING. AFTER MONDAY EVENING...HOWEVER...THE MODEL DATA
BEGINS TO DIVERGE...LEAVING US WITH AN UNCERTAIN FORECAST FROM
MONDAY NIGHT ONWARD. FOR NOW...WITH THE MODELS SHOWING A SERIES OF
FAST MOVING SHORT WAVES EJECTING OUT OF THE PLAINS AND ACROSS THE
EASTERN THIRD OF THE CONUS...DECIDED TO GO WITH LOW PRECIPITATION
CHANCES SUNDAY NIGHT THROUGH LATE MONDAY NIGHT. AFTER ANOTHER
POSSIBLE DRY PERIOD TUESDAY AND TUESDAY NIGHT...INTRODUCED MORE
RAIN CHANCES WEDNESDAY THROUGH THURSDAY...AS THE ECMWF MODEL TRIES
TO BRING A FAIRLY WELL DEVELOPED AREA OF LOW PRESSURE OUT OF THE
PLAINS AND ACROSS THE UPPER MISSISSIPPI VALLEY AND GREAT LAKES
REGIONS. THE SURFACE FRONT THAT WOULD BE ASSOCIATED WITH THIS
UPPER LOW WOULD WHAT WOULD BRING RAINFALL TO OUR AREA.
HOWEVER...THE GFS MODEL IS DRY FOR THURSDAY...WHEN THE ECMWF HAS
AN AREA OF RAINFALL AFFECTING THE AREA. WITH THAT IN MIND...WENT
WITH ONLY A SLIGHT CHANCE OF RAIN ACROSS EASTERN KENTUCKY FOR THE
WEDNESDAY THURSDAY TIME FRAME.
TEMPERATURES ACROSS THE AREA ARE EXPECTED TO BE GENERALLY ABOVE
NORMAL THROUGH OUT THE PERIOD...WITH DAY TIME HIGHS IN THE MID TO
UPPER 50S AND OVERNIGHT LOWS IN THE MID TO UPPER 30S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 656 AM EST FRI DEC 4 2015
A FEW INSTANCES OF PATCHY FOG HAVE BEEN REPORTED AT KSME AND KSYM
THIS MORNING...AND GIVEN THAT TEMPERATURES ARE BELOW FREEZING AT
THESE LOCATIONS...THIS IS LIKELY A FREEZING FOG SET UP. IMPACTS
SHOULD BE MINIMAL HOWEVER...AND FOG TO BURN OFF OVER THE NEXT 1
TO 2 HOURS AS WE START WARMING. OTHERWISE...HIGH PRESSURE WILL
REMAIN IN CONTROL OF THE REGION THROUGHOUT THE TAF PERIOD...
RESULTING IN LIGHT WINDS AND VFR/CLEAR CONDITIONS.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...DJ
SHORT TERM...JMW
LONG TERM...AR
AVIATION...JMW
Area Forecast Discussion
National Weather Service Louisville KY
1057 AM EST FRI DEC 4 2015
...Forecast Update...
Issued at 1055 AM Fri Dec 4 2015
Fog is finally dissipating in a lot of the valleys, but the more
extensive area of fog/stratus over Indiana is going nowhere fast.
Have updated products to remove the fog mention, except over our
northernmost counties in southern Indiana, where the clouds/fog will
hang on for much of the afternoon. Temps are just warm enough that
in daylight conditions, freezing fog should not be as much of an
issue as it had been earlier. Therefore will just keep it plain old
fog. Have clipped max temps by several degrees where the clouds and
fog remain, but if it`s persistent enough, even the mid 40s in the
revised forecast may be too generous. Still on track for around 50
elsewhere.
Issued at 925 AM Fri Dec 4 2015
Patchy freezing fog is mostly dissipating based on latest METARs and
area webcams. Still seeing some of the deeper river valleys pretty
well socked in, so will take a bit slower approach to removing the
early fog wording from the ZFP. A more extensive area of fog/stratus
sits over Indiana just north of our CWA boundary, and I have little
confidence that it will go anywhere given poor mixing under a 1037mb
high pressure, and low December sun angle. That said, the current
forecast should be pretty well on track, so will just refresh to
pull the fog wording as the valleys finally start to mix a bit, and
will keep an eye on whether the stratus deck tries to creep into our
Indiana counties.
.SHORT TERM (Now through Saturday)...
Issued at 300 AM EST Fri Dec 4 2015
In the near term, high pressure will drift overhead early this
morning and then move slowly eastward during the day today. IR
satellite imagery reveals clear skies across the region. A decent
ridge/valley decoupling has taken place with the cooler valleys
presently sitting in the mid 20s with upper 20s to around 30
elsewhere. Dry air is abundant aloft across the region. However,
we do have some low-level moisture down near the surface which may
result in some areas of freezing fog this morning. The best chances
for the fog look to be across our southern Indiana counties and in
the KY river valley region of central KY. Temperatures may cool a
few more degrees before sunrise with most locations seeing readings
in the low-mid 20s in the valleys and in the mid-upper 20s elsewhere.
For Today through Saturday, quiet weather is expected as high
pressure will continue to dominance our weather pattern. Highs this
afternoon will warm into the upper 40s to around 50 in the north
with lower 50s likely across southern KY. Another cool night looks
likely tonight with lows in the valleys cooling into the lower-mid
20s with mid-upper 20s elsewhere. We will pick up a bit more
southerly flow on Saturday with mostly sunny skies. Temperatures
look to warm into the lower 50s in the north with low-mid 50s across
the south.
.LONG TERM (Saturday Night through Thursday)...
Issued at 323 AM EST Fri Dec 4 2015
In the long term period, a progressive flow will remain in place
aloft with a series of compact upper level lows rolling from east to
west across the CONUS. The first of these will transverse our
region late Sunday and into the day on Monday. Moisture is not all
that plentiful with the system as return flow from the Gulf will not
have sufficient time to moisten up the column. However, model time-
height cross sections do suggest plenty of mid-high level cloud
cover to push through with this system. Ascent is not overly
strong, but forcing with the upper low (mainly due to steep lapse
rates) look to be enough to continue low chance PoPs in the Sunday
night/Monday time frame.
The upper flow will then flatten back out by Tuesday, only to re-
amplify as the next upper level low crosses the region Wednesday
night into Thursday as it ejects from the northern Plains. Again,
large scale ascent with this system is not overly impressive, but
enough moisture and lift look available to warrant low chance PoPs
in the Wed night/Thursday time frame...despite the blended guidance
being a little more optimistic on dry conditions.
Temperatures through the period look to run a little above seasonal
normals. Typical early December highs average in the upper 40s. The
latest guidance suggests daily highs in the lower to middle 50s with
overnight lows in the mid-upper 30s. The warmest day looks to be
Thursday where some upper 50s across the south will be possible.
Overall, not much in the way of change from the previous forecast.
Looking further out, a more active weather pattern looks to take
shape as we head into late next week and into the mid part of
December. Latest teleconnection pattern suggest a
+AO/+NAO/+PNA/+EPO pattern in place by late next week. These
indices would support the series of rolling upper level lows across
the CONUS. However, as we head down the road, the models suggest a
downward trend in all the indices as we head toward mid-month. As
this downward trend occurs, we`re likely to see an active weather
pattern set up across the central US and eventually into the Ohio
Valley.
Initially, we`ll be on the warm side of the pattern with the threat
of additional heavy rainfall and milder than normal temperatures. As
the indices slide toward the neutral/negative range, we`ll
gradually see the sensible weather catch up with a more seasonal
cold pattern emerging after mid-month. It should be noted that the
long term models have struggled with timing of the downtrend in the
teleconnection indices. Past verification shows that they tend to
drop the indices too quick...so it would not be surprising to see
the eventual return to seasonal cold to be delayed slightly in later
forecasts.
&&
.AVIATION (12Z TAF Update)...
Updated at 610 AM EST Fri Dec 4 2015
Patchy fog/mist this morning at SDF/LEX/BWG will burn off between 13-
14z. Latest satellite imagery shows a LIFR stratus deck over east-
central IL and central IN, trying to expand southward. HRRR is
capturing this somewhat, best of the hi-res models, and takes it
southward to near the Ohio River in a few hours. It then should
either scatter out due to daytime mixing or retreat back to the
north. Given this though, still think SDF will remain clear but will
have to watch trends closely as models sometime poorly handle
shallow moisture within an inversion.
Otherwise, expect light/variable winds through the period. Another
clear/calm night will promote light fog formation at all sites,
starting after 06z.
&&
.LMK Watches/Warnings/Advisories...
KY...NONE.
IN...NONE.
&&
$$
Update.........RAS
Short Term.....MJ
Long Term......MJ
Aviation.......ZBT
AREA FORECAST DISCUSSION
NWS JACKSON KY
958 AM EST FRI DEC 4 2015
.UPDATE...
ISSUED AT 958 AM EST FRI DEC 4 2015
VIS SAT CONTINUES TO SHOW RIVER VALLEY FOG...WHICH GIVEN THE TEMPS
THIS MORNING WILL LIKELY BE FREEZING FOG. NO ISSUES ROAD WISE ARE
EXPECTED THIS MORNING. THIS VALLEY FOG WILL CONTINUE TO DISSIPATE
THROUGH THE MORNING HOURS. UPDATED GRIDS TO REFLECT VALLEY FOG
LOCATIONS...OTHERWISE NOT MAJOR CHANGES NEEDED THIS UPDATE. DID
OPT TO UPDATE THE TEMP...DEWS... AND WINDS WITH LATEST OBS AND
TRENDS. GRIDS HAVE BEEN SENT TO NDFD.
UPDATE ISSUED AT 727 AM EST FRI DEC 4 2015
SINCE ALL TEMPERATURES ACROSS THE REGION ARE BELOW FREEZING...IT
IS LIKELY THAT WHATEVER PATCHY FOG HAS DEVELOPED ACROSS THE REGION
IS OF THE FREEZING VARIETY. AS SUCH...CHANGED WEATHER GRIDS FOR
THE NEXT COUPLE HOURS TO REFLECT PATCHY FREEZING FOG INSTEAD.
ALSO HIGHLIGHTED POTENTIAL IMPACTS IN THE HWO. HOWEVER...GIVEN THE
PATCHY NATURE OF THE FOG AND WITH LITTLE TO NO IMPACTS REPORTED
THUS FAR...DID NOT ISSUE ANY FURTHER PRODUCTS. MOST REPORTS THIS
MORNING HAVE BEEN FOR FROST RATHER THAN FOG. REGARDLESS...ANY
REMAINING FOG SHOULD BURN OFF OVER THE NEXT HOUR OR TWO AS WE
CONTINUE TO WARM UP. LOADED IN THE LATEST OBSERVATIONS TO MAKE
SURE THE NEAR TERM FORECAST WAS WELL ON TRACK WITH THE CURRENT
CONDITIONS. A NEW FORECAST PACKAGE WAS SENT OUT TO REFLECT THE
CHANGES IN FOG WORDING. ALL GRIDS WERE PUBLISHED AND SENT TO
NDFD/WEB.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 242 AM EST FRI DEC 4 2015
HIGH PRESSURE IS CURRENTLY DIRECTLY OVERHEAD THE STATE OF KENTUCKY
AS OF 7Z. THIS IS PROVIDING LIGHT WINDS AND STRONG SUBSIDENCE DURING
THE OVERNIGHT HOURS. WENT AHEAD AND LOWERED SOME OF THE DEEPER
VALLEY LOCATIONS LOW TEMPERATURES FOR EARLY THIS MORNING GIVEN THE
CURRENT OBSERVATIONS.
OTHERWISE...EXPECT QUIET AND CLEAR CONDITIONS THROUGH THE DURATION
OF THE SHORT TERM PERIOD AS THE HIGH PRESSURE REMAINS OVERHEAD.
AFTERNOON TEMPERATURES WILL CONTINUE TO SHOW AN INCREASING
TREND...WITH HIGHS TODAY TOPPING OUT AROUND THE 50 DEGREE
MARK...THEN CLIMBING TO THE MID TO UPPER 50S BY TOMORROW. STRONG
SUBSIDENCE AND MAXIMUM RADIATIONAL COOLING OVERNIGHT TONIGHT WILL
PROMOTE ANOTHER RIDGE VALLEY SPLIT AND SIGNIFICANT DIURNAL
DROPS...WITH UPPER 20S TO AROUND 30 EXPECTED ON THE RIDGES FOR
LOWS...AND LOW TO MID 20S IN THE VALLEYS.
THE ONE CONCERN DURING THIS FORECAST PERIOD WILL BE THE AMOUNT OF
DRY AIR BEING USHERED INTO THE REGION UNDER THE INFLUENCE OF THIS
HIGH PRESSURE SYSTEM. THIS WILL CREATE LOW DEW POINTS AND LOW RH
SITUATIONS BOTH THIS AFTERNOON...AND EVEN MORE SO SATURDAY
AFTERNOON. LUCKILY...WINDS WILL BE LIGHT AND PREVIOUS DAYS RAINS
WILL HELP TO MITIGATE SOME OF THE FIRE CONCERNS...BUT THIS WILL
CONTINUE TO BE SOMETHING TO MONITOR THROUGH THE UPCOMING WEEKEND.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 458 AM EST FRI DEC 4 2015
THE EXTENDED PERIOD WILL START OUT DRY AND PLEASANT...WITH ABOVE
NORMAL TEMPERATURES EXPECTED DURING THE DAY ON SUNDAY.
HOWEVER...CONDITIONS WILL START OUT QUITE COLD ACROSS THE AREA ON
SUNDAY MORNING...WITH LOWS DROPPING INTO THE LOW TO MID 20S IN OUR
VALLEYS...WHILE THE SURROUNDING RIDGES ONLY FALL INTO THE LOW TO
MID 30S. THE WEATHER IS EXPECTED TO REMAIN DRY THROUGH EARLY
MONDAY EVENING. AFTER MONDAY EVENING...HOWEVER...THE MODEL DATA
BEGINS TO DIVERGE...LEAVING US WITH AN UNCERTAIN FORECAST FROM
MONDAY NIGHT ONWARD. FOR NOW...WITH THE MODELS SHOWING A SERIES OF
FAST MOVING SHORT WAVES EJECTING OUT OF THE PLAINS AND ACROSS THE
EASTERN THIRD OF THE CONUS...DECIDED TO GO WITH LOW PRECIPITATION
CHANCES SUNDAY NIGHT THROUGH LATE MONDAY NIGHT. AFTER ANOTHER
POSSIBLE DRY PERIOD TUESDAY AND TUESDAY NIGHT...INTRODUCED MORE
RAIN CHANCES WEDNESDAY THROUGH THURSDAY...AS THE ECMWF MODEL TRIES
TO BRING A FAIRLY WELL DEVELOPED AREA OF LOW PRESSURE OUT OF THE
PLAINS AND ACROSS THE UPPER MISSISSIPPI VALLEY AND GREAT LAKES
REGIONS. THE SURFACE FRONT THAT WOULD BE ASSOCIATED WITH THIS
UPPER LOW WOULD WHAT WOULD BRING RAINFALL TO OUR AREA.
HOWEVER...THE GFS MODEL IS DRY FOR THURSDAY...WHEN THE ECMWF HAS
AN AREA OF RAINFALL AFFECTING THE AREA. WITH THAT IN MIND...WENT
WITH ONLY A SLIGHT CHANCE OF RAIN ACROSS EASTERN KENTUCKY FOR THE
WEDNESDAY THURSDAY TIME FRAME.
TEMPERATURES ACROSS THE AREA ARE EXPECTED TO BE GENERALLY ABOVE
NORMAL THROUGH OUT THE PERIOD...WITH DAY TIME HIGHS IN THE MID TO
UPPER 50S AND OVERNIGHT LOWS IN THE MID TO UPPER 30S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 656 AM EST FRI DEC 4 2015
A FEW INSTANCES OF PATCHY FOG HAVE BEEN REPORTED AT KSME AND KSYM
THIS MORNING...AND GIVEN THAT TEMPERATURES ARE BELOW FREEZING AT
THESE LOCATIONS...THIS IS LIKELY A FREEZING FOG SET UP. IMPACTS
SHOULD BE MINIMAL HOWEVER...AND FOG TO BURN OFF OVER THE NEXT 1
TO 2 HOURS AS WE START WARMING. OTHERWISE...HIGH PRESSURE WILL
REMAIN IN CONTROL OF THE REGION THROUGHOUT THE TAF PERIOD...
RESULTING IN LIGHT WINDS AND VFR/CLEAR CONDITIONS.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...DJ
SHORT TERM...JMW
LONG TERM...AR
AVIATION...JMW
Area Forecast Discussion
National Weather Service Louisville KY
928 AM EST FRI DEC 4 2015
...Forecast Update...
Issued at 925 AM Fri Dec 4 2015
Patchy freezing fog is mostly dissipating based on latest METARs and
area webcams. Still seeing some of the deeper river valleys pretty
well socked in, so will take a bit slower approach to removing the
early fog wording from the ZFP. A more extensive area of fog/stratus
sits over Indiana just north of our CWA boundary, and I have little
confidence that it will go anywhere given poor mixing under a 1037mb
high pressure, and low December sun angle. That said, the current
forecast should be pretty well on track, so will just refresh to
pull the fog wording as the valleys finally start to mix a bit, and
will keep an eye on whether the stratus deck tries to creep into our
Indiana counties.
.SHORT TERM (Now through Saturday)...
Issued at 300 AM EST Fri Dec 4 2015
In the near term, high pressure will drift overhead early this
morning and then move slowly eastward during the day today. IR
satellite imagery reveals clear skies across the region. A decent
ridge/valley decoupling has taken place with the cooler valleys
presently sitting in the mid 20s with upper 20s to around 30
elsewhere. Dry air is abundant aloft across the region. However,
we do have some low-level moisture down near the surface which may
result in some areas of freezing fog this morning. The best chances
for the fog look to be across our southern Indiana counties and in
the KY river valley region of central KY. Temperatures may cool a
few more degrees before sunrise with most locations seeing readings
in the low-mid 20s in the valleys and in the mid-upper 20s elsewhere.
For Today through Saturday, quiet weather is expected as high
pressure will continue to dominance our weather pattern. Highs this
afternoon will warm into the upper 40s to around 50 in the north
with lower 50s likely across southern KY. Another cool night looks
likely tonight with lows in the valleys cooling into the lower-mid
20s with mid-upper 20s elsewhere. We will pick up a bit more
southerly flow on Saturday with mostly sunny skies. Temperatures
look to warm into the lower 50s in the north with low-mid 50s across
the south.
.LONG TERM (Saturday Night through Thursday)...
Issued at 323 AM EST Fri Dec 4 2015
In the long term period, a progressive flow will remain in place
aloft with a series of compact upper level lows rolling from east to
west across the CONUS. The first of these will transverse our
region late Sunday and into the day on Monday. Moisture is not all
that plentiful with the system as return flow from the Gulf will not
have sufficient time to moisten up the column. However, model time-
height cross sections do suggest plenty of mid-high level cloud
cover to push through with this system. Ascent is not overly
strong, but forcing with the upper low (mainly due to steep lapse
rates) look to be enough to continue low chance PoPs in the Sunday
night/Monday time frame.
The upper flow will then flatten back out by Tuesday, only to re-
amplify as the next upper level low crosses the region Wednesday
night into Thursday as it ejects from the northern Plains. Again,
large scale ascent with this system is not overly impressive, but
enough moisture and lift look available to warrant low chance PoPs
in the Wed night/Thursday time frame...despite the blended guidance
being a little more optimistic on dry conditions.
Temperatures through the period look to run a little above seasonal
normals. Typical early December highs average in the upper 40s. The
latest guidance suggests daily highs in the lower to middle 50s with
overnight lows in the mid-upper 30s. The warmest day looks to be
Thursday where some upper 50s across the south will be possible.
Overall, not much in the way of change from the previous forecast.
Looking further out, a more active weather pattern looks to take
shape as we head into late next week and into the mid part of
December. Latest teleconnection pattern suggest a
+AO/+NAO/+PNA/+EPO pattern in place by late next week. These
indices would support the series of rolling upper level lows across
the CONUS. However, as we head down the road, the models suggest a
downward trend in all the indices as we head toward mid-month. As
this downward trend occurs, we`re likely to see an active weather
pattern set up across the central US and eventually into the Ohio
Valley.
Initially, we`ll be on the warm side of the pattern with the threat
of additional heavy rainfall and milder than normal temperatures. As
the indices slide toward the neutral/negative range, we`ll
gradually see the sensible weather catch up with a more seasonal
cold pattern emerging after mid-month. It should be noted that the
long term models have struggled with timing of the downtrend in the
teleconnection indices. Past verification shows that they tend to
drop the indices too quick...so it would not be surprising to see
the eventual return to seasonal cold to be delayed slightly in later
forecasts.
&&
.AVIATION (12Z TAF Update)...
Updated at 610 AM EST Fri Dec 4 2015
Patchy fog/mist this morning at SDF/LEX/BWG will burn off between 13-
14z. Latest satellite imagery shows a LIFR stratus deck over east-
central IL and central IN, trying to expand southward. HRRR is
capturing this somewhat, best of the hi-res models, and takes it
southward to near the Ohio River in a few hours. It then should
either scatter out due to daytime mixing or retreat back to the
north. Given this though, still think SDF will remain clear but will
have to watch trends closely as models sometime poorly handle
shallow moisture within an inversion.
Otherwise, expect light/variable winds through the period. Another
clear/calm night will promote light fog formation at all sites,
starting after 06z.
&&
.LMK Watches/Warnings/Advisories...
KY...NONE.
IN...NONE.
&&
$$
Update.........RAS
Short Term.....MJ
Long Term......MJ
Aviation.......ZBT
AREA FORECAST DISCUSSION
National Weather Service Paducah KY
526 AM CST FRI DEC 4 2015
.UPDATE...
Issued at 526 AM CST FRI DEC 4 2015
The AVIATION section has been updated for the 12Z TAF issuance.
&&
.SHORT TERM...(Today through Sunday)
Issued at 248 AM CST FRI DEC 4 2015
Previous forecast update issued at 213 am CST Friday Dec 4 2015
discussed the Dense Fog Advisory/black ice potential, so will not
cover again here. However, did add a special weather statement for
the remainder of the WFO PAH forecast area until 8 am CST to
handle isolated fog/black ice potential outside the advisory
area.
With the center of high pressure expected to move east of the area
later today, a general easterly flow should persist across the
region through at least 15z (9 am CST) Saturday, before becoming
broadly southeasterly and South for the remainder of the short
term forecast period. Strong insolation (outside of the fog areas)
and shallow mixing should bring temperatures back into the 50s
today.
The 00z deterministic runs of the 20 km GFS, SREF, and 12km NAM-
WRF seem to have a good handle on the the closed low off Vancouver
Island this morning, with the advancing north to south shortwave
along the western U.S. coastline. For the short term time period,
mainly Sunday, this shortwave may provide sufficient lift to
generate some patchy sprinkles or drizzle across the area. Most
areas will likely remain dry, but added a mention in the gridded
forecast to handle the low probability occurrence of trace
precipitation. Main rain chances for the period are addressed in
the long term forecast discussion.
.LONG TERM...(Sunday Night through Friday)
Issued at 248 AM CST FRI DEC 4 2015
Overall forecast confidence is moderate at this time. The details of
small-scale upper-level disturbances moving east through/near the
region will clutter the PoP forecast, as the models are struggling
to handle them consistently. However, the overwhelming signal is for
near normal temperatures at the beginning of the period to warm up
some 5 to 10 degrees above normal through the work week.
The models continue to bring an upper-level storm system eastward
through the region Sunday night and Monday. The 00Z ECMWF is most
consistent with the consensus from last night`s models. It spits out
scant QPF late Sunday into Sunday night. The 00Z is a bit wetter and
slower emphasizing Sunday night into Monday. Will keep slight
chances of what should be very light rain or drizzle mainly behind
the cold front Sunday night and Monday.
The medium-range models have an energetic zonal flow crashing into
the Pacific Northwest for much of the week. Individual disturbances
in the flow amplify into closed lows as they emerge out of the
Rockies. The question is how far south does this amplification
occur? The farther south the development the slower the progression
eastward. This causes fairly wide differences in timing features
through/near our region, which causes considerable uncertainty in
the PoPs generally from Tuesday night through the remainder of the
work week.
Would prefer to keep the forecast dry beyond Monday and wait for
more clarity in the models before introducing PoPs, but border
constraints make that impossible at this time. Dried it out when and
where I could, but there remain a few areas of low chance PoPs from
Wednesday through Friday.
The overall flow pattern diverges considerably between the GFS and
ECMWF by next week, so confidence declines heading into Thursday and
especially Friday. However, there is no sign of cold air to impact
the region, so the relatively mild conditions will continue.
&&
.AVIATION...
Issued at 526 AM CST FRI DEC 4 2015
Very dry surface high pressure will dominate the region throughout
the 12Z TAF period, so the only potential problem for aviation
will be late night/early morning fog formation. Lots of MVFR to
IFR visibilities across the area this morning, but the large area
of dense fog has stayed north of the TAF sites so far and it is
not expected to bodily move over any of them this morning. A light
northeast wind will mix down this afternoon, but they will likely
go calm again tonight. Guidance is choking on the dry air and is
not developing any fog tonight. Persistence tells a different
story, but we will assume that more mixing this afternoon will
keep the fog in check tonight.
&&
.PAH Watches/Warnings/Advisories...
IL...Dense Fog Advisory until 11 AM CST this morning for ILZ075>078-
080>090-092-093.
MO...Dense Fog Advisory until 11 AM CST this morning for MOZ076-086-
087-100-107>111-114.
IN...Dense Fog Advisory until 11 AM CST this morning for INZ081-082-
085>087.
KY...Dense Fog Advisory until 11 AM CST this morning for KYZ018.
&&
$$
UPDATE...DRS
SHORT TERM...Smith
LONG TERM...Smith
AVIATION...DRS
Area Forecast Discussion
National Weather Service Louisville KY
608 AM EST FRI DEC 4 2015
...Updated Aviation Discussion...
.SHORT TERM (Now through Saturday)...
Issued at 300 AM EST Fri Dec 4 2015
In the near term, high pressure will drift overhead early this
morning and then move slowly eastward during the day today. IR
satellite imagery reveals clear skies across the region. A decent
ridge/valley decoupling has taken place with the cooler valleys
presently sitting in the mid 20s with upper 20s to around 30
elsewhere. Dry air is abundant aloft across the region. However,
we do have some low-level moisture down near the surface which may
result in some areas of freezing fog this morning. The best chances
for the fog look to be across our southern Indiana counties and in
the KY river valley region of central KY. Temperatures may cool a
few more degrees before sunrise with most locations seeing readings
in the low-mid 20s in the valleys and in the mid-upper 20s elsewhere.
For Today through Saturday, quiet weather is expected as high
pressure will continue to dominance our weather pattern. Highs this
afternoon will warm into the upper 40s to around 50 in the north
with lower 50s likely across southern KY. Another cool night looks
likely tonight with lows in the valleys cooling into the lower-mid
20s with mid-upper 20s elsewhere. We will pick up a bit more
southerly flow on Saturday with mostly sunny skies. Temperatures
look to warm into the lower 50s in the north with low-mid 50s across
the south.
.LONG TERM (Saturday Night through Thursday)...
Issued at 323 AM EST Fri Dec 4 2015
In the long term period, a progressive flow will remain in place
aloft with a series of compact upper level lows rolling from east to
west across the CONUS. The first of these will transverse our
region late Sunday and into the day on Monday. Moisture is not all
that plentiful with the system as return flow from the Gulf will not
have sufficient time to moisten up the column. However, model time-
height cross sections do suggest plenty of mid-high level cloud
cover to push through with this system. Ascent is not overly
strong, but forcing with the upper low (mainly due to steep lapse
rates) look to be enough to continue low chance PoPs in the Sunday
night/Monday time frame.
The upper flow will then flatten back out by Tuesday, only to re-
amplify as the next upper level low crosses the region Wednesday
night into Thursday as it ejects from the northern Plains. Again,
large scale ascent with this system is not overly impressive, but
enough moisture and lift look available to warrant low chance PoPs
in the Wed night/Thursday time frame...despite the blended guidance
being a little more optimistic on dry conditions.
Temperatures through the period look to run a little above seasonal
normals. Typical early December highs average in the upper 40s. The
latest guidance suggests daily highs in the lower to middle 50s with
overnight lows in the mid-upper 30s. The warmest day looks to be
Thursday where some upper 50s across the south will be possible.
Overall, not much in the way of change from the previous forecast.
Looking further out, a more active weather pattern looks to take
shape as we head into late next week and into the mid part of
December. Latest teleconnection pattern suggest a
+AO/+NAO/+PNA/+EPO pattern in place by late next week. These
indices would support the series of rolling upper level lows across
the CONUS. However, as we head down the road, the models suggest a
downward trend in all the indices as we head toward mid-month. As
this downward trend occurs, we`re likely to see an active weather
pattern set up across the central US and eventually into the Ohio
Valley.
Initially, we`ll be on the warm side of the pattern with the threat
of additional heavy rainfall and milder than normal temperatures. As
the indices slide toward the neutral/negative range, we`ll
gradually see the sensible weather catch up with a more seasonal
cold pattern emerging after mid-month. It should be noted that the
long term models have struggled with timing of the downtrend in the
teleconnection indices. Past verification shows that they tend to
drop the indices too quick...so it would not be surprising to see
the eventual return to seasonal cold to be delayed slightly in later
forecasts.
&&
.AVIATION (12Z TAF Update)...
Updated at 610 AM EST Fri Dec 4 2015
Patchy fog/mist this morning at SDF/LEX/BWG will burn off between 13-
14z. Latest satellite imagery shows a LIFR stratus deck over east-
central IL and central IN, trying to expand southward. HRRR is
capturing this somewhat, best of the hi-res models, and takes it
southward to near the Ohio River in a few hours. It then should
either scatter out due to daytime mixing or retreat back to the
north. Given this though, still think SDF will remain clear but will
have to watch trends closely as models sometime poorly handle
shallow moisture within an inversion.
Otherwise, expect light/variable winds through the period. Another
clear/calm night will promote light fog formation at all sites,
starting after 06z.
&&
.LMK Watches/Warnings/Advisories...
KY...NONE.
IN...NONE.
&&
$$
Short Term........MJ
Long Term.........MJ
Aviation..........ZT
AREA FORECAST DISCUSSION
National Weather Service Paducah KY
213 AM CST FRI DEC 4 2015
.UPDATE...
Issued at 213 AM CST FRI DEC 4 2015
Just issued a Dense Fog Advisory for parts of the WFO PAH forecast
area until 11 am CST. Had considered a Freezing Fog Advisory, but
temperatures should rise above freezing between 14z-15z (8-9 am
CST) today. To address the freezing component, emphasized the
development of black ice, given the sub-freezing temperatures
already in place across the WFO PAH forecast area.
Frost has already been deposited across most areas from the early
evening, so further condensation is likely along and the the west
and north of the surface ridge axis overnight and through the
morning. Given the decent inversion aloft, it will take some time
for insolation (sunshine) to erode the edges of the fog layer
inward until 17z (11 am CST) at the latest.
The HRRR and SREF visibility guidance values for fog are
initializing fairly well. May have went out on a limb for
including Southeast Missouri in the Dense Fog Advisory , but
visibility trends continue to slowly move downward, so may see
criteria level visibilities no later than 10z-11z in that area.
&&
.SHORT TERM...(This evening through Saturday night)
Issued at 233 PM CST THU DEC 3 2015
An analysis of the morning and modeled sounding data reveals a
strong inversion from about 2500 FT to about 6500 FT AGL, and this
has kept the small riboon of clouds below 2000 FT from burning
off. These clouds will continue to scrape our northern tier border
counties into the early evening, and otherwise, clear skies will
abound. This will enable another night of good radiational cooling
to allow Lows to dip into the 20s again tonight.
Tmrw, the High pressure center nudges eastward across the Ohio
river valley, underneath the High aloft. Easterlies in the lower
trop will cease the deeper cold advection and result in a warming
to around 50, despite the cold start.
Friday night and Saturday sees the High(s) move further east,
allowing light return flow southerlys to begin again. Temps will
nudge upwards a couple or three degrees from the previous days
readings then...returning closer to norms for this time of year.
.LONG TERM...(Sunday through Thursday)
Issued at 233 PM CST THU DEC 3 2015
Sfc winds will be out of the south by Sun ahead of a fast-moving mid
level shrtwv trof that is progged by the med range models to dive
into the central Plains and then ewd through the PAH forecast area
late in the weekend. The odd model out continues to be the GFS (and
its ensemble means), which has a slower, wetter, and farther south
solution with the trof/low. The UKMET continues to show the feature
as an open wave, and appears the fastest. Other med range models
have something in between.
Deep moist return flow appears very limited with this feature, and
thus moisture will be limited above about 850 mb. Currently, we are
forecasting rainfall amounts a tenth of an inch or less, mainly
behind the sfc cold front. Relatively mild conditions will prevail
behind the front, as the new airmass will be of Pacific origin.
The 12Z ECMWF model, and to a lesser degree, the GFS, suggest the
possibility that one of the ripples in the wavy mid level flow later
in the week may produce pcpn in a similar way (not shown
significantly in the initialization blend). For now we left the
forecast dry, and will see what later model runs reveal.
&&
.AVIATION...
Issued at 1032 PM CST THU DEC 3 2015
May have to consider MVFR vsbys at the terminals through the
early a.m. Other nearby sights at cross over with calm winds and
clear skies the rule. Otherwise high pressure will result in cloud
free skies and light winds Friday through Friday evening.
&&
.PAH Watches/Warnings/Advisories...
IL...Dense Fog Advisory until 11 AM CST this morning for ILZ075>078-
080>090-092-093.
MO...Dense Fog Advisory until 11 AM CST this morning for MOZ076-086-
087-100-107>111-114.
IN...Dense Fog Advisory until 11 AM CST this morning for INZ081-082-
085>087.
KY...Dense Fog Advisory until 11 AM CST this morning for KYZ018.
&&
$$
UPDATE...Smith
AREA FORECAST DISCUSSION
NWS GRAY ME
930 PM EST SAT DEC 5 2015
.SYNOPSIS...
HIGH PRESSURE CENTERED SOUTH OF NEW ENGLAND WILL REMAIN STATIONARY
THROUGH SUNDAY. A WEAK COLD FRONT WILL DROP SOUTH THROUGH THE
REGION SUNDAY NIGHT AND MONDAY FOLLOWED BY ANOTHER AREA OF HIGH
PRESSURE. HIGH PRESSURE WILL HOLD OVER THE REGION TUESDAY THROUGH
WEDNESDAY AS LOW PRESSURE PASSES WELL OFFSHORE. A WARM FRONT WILL
APPROACH FROM THE SOUTHWEST WEDNESDAY NIGHT AND WILL GRADUALLY
LIFT INTO SOUTHERN NEW ENGLAND ON THURSDAY AND INTO NORTHERN NEW
ENGLAND FRIDAY.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
900 PM UPDATE...ENSEMBLE AND HRRR GUIDANCE IS INDICATING LOW
VISIBILITIES TONIGHT ALONG THE CT RIVER VALLEY AND UP THROUGH THE
MAINE MIDCOAST. ADDED PATCHY FREEZING FOG FOR OVERNIGHT. ALSO,
TEMPERATURES HAVE RADIATED OUT QUITE QUICKLY...ESPECIALLY ACROSS
THE NORTHERN NEW HAMPSHIRE...SO LOWERED FORECAST LOW TEMPERATURES
A BIT TO LINE UP WITH CURRENT OBS AND TRENDS. THE BIGGEST FORECAST
CONCERN WILL BE THE POTENTIAL FOR BLACK ICE ON ROADS TONIGHT WITH
FREEZING FOG DEVELOPING.
515 PM UPDATE...CLEAR SKIES ACROSS MOST OF THE FORECAST AREA
EXCEPT FOR THE FAR NORTH THIS EVENING. SHOULD RADIATE OUT QUITE
EFFICIENTLY AND LOOKING AT THE LATEST OB TRENDS TEMPS HAS COOLED
ABOUT 5 DEGREES IN THE PAST HOUR AFTER SUNSET. WENT A BIT COOLER
FOR OVERNIGHT LOWS TONIGHT AS THIS TREND SHOULD CONTINUE WITH THE
CLEAR SKIES AND LIGHT WINDS.
PREVIOUS DISCUSSION... SFC HIGH BUILDS OVER NEW ENGLAND TONIGHT
WITH AND DESPITE WARMING AIR ALOFT WILL SEE GOOD RAD COOLING
/ALTHOUGH WITHOUT SNOW/ AND TEMPS WILL DROP BACK INTO THE LOW TO
MID 20S IN MANY SPOTS TO AROUND 30 ON THE COAST. ANY EVENING
CLOUDS IN THE MTNS WILL CLEAR LATER TONIGHT...WITH A FEW CIRRUS
MOVING THRU AFTER MIDNIGHT.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...
SFC HIGH HOLDS OVER THE CWA DURING MOST OF THE DAY...BUT WEAK
500MB WAVE PASSING TO OUR N WILL SUPPRESS THE RIDGE ALOFT...AND
ALLOW A WEAK COLD FRONT TO SLIP THRU THE CWA SUN NIGHT.
SUNDAY WILL BE MAINLY AND SUNNY AND MILD...AS SW FLOW INCREASES
AHEAD OF THE FRONT WILL BE ABLE TO BETTER MIX THE WARM AIR ALOFT
THAT SATURDAY AND HIGHS WILL BE A FEW DEGREES WARMER...RANGING
FROM THE MID TO UPPER 40S IN THE MTNS TO THE LOW TO MID 50S...AND
EVEN A FEW UPPER 50S...NEAR THE SW ME COAST AND IN SRN NH.
THE COLD FRONT WILL MOVE THROUGH WITH LITTLE FANFARE SUN
NIGHT...PROBABLY DURING THE LATTER PART OF THE NIGHT...AND WILL
PRODUCE A SCT-BKN MID LVL CLOUDS...BUT NO PRECIP. LOWS WILL
RANGE FROM THE MID 20S N TO LOW 30S S.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
THE MODELS CONTINUE TO SUGGEST THE MEAN LONG WAVE TROUGH REMAINS IN
THE WESTERN US ALLOWING THE LONG WAVE RIDGE AXIS TO MAINTAIN
ITSELF IN THE EAST. HAVE NO REASON TO ARGUE THIS GENERAL PATTERN
WILL CONTINUE THIS OUTLOOK PERIOD.
SO...HIGH PRESSURE WILL DOMINATE OVER OUR AREA THROUGH MIDWEEK. A TEMPORARY
SPLIT FLOW IN THE EAST ALLOWS A SYSTEM TO MOVE OFF THE MID
ATLANTIC COAST AND PASS WELL SOUTH OF NEW ENGLAND TUE AND WED.
THEN LATE IN THE WEEK A SHORT WAVE TROF MOVING THROUGH THE ZONAL
FLOW WILL ALLOW A WARM FRONT TO APPROACH AND EVENTUALLY MOVE NORTH
THROUGH THE AREA LATE THU AND FRIDAY. A WEAK WAVE MAY EVEN DEVELOP
ALONG THE WARM FRONT AS SUGGESTED BY THE EURO. SOME VERY LIGHT
MIXED PCPN MAY OCCUR AHEAD OF THAT SYSTEM BUT WILL BE VERY MINOR.
TEMPERATURES WILL REMAIN ABOVE NORMAL THROUGH THE OUTLOOK PERIOD.
&&
.AVIATION /02Z SUNDAY THROUGH THURSDAY/...
SHORT TERM...
900 PM UPDATE...VLIFR CONDITIONS WILL BE POSSIBLE LATE TONIGHT
INTO TOMORROW MORNING WITH FREEZING FOG DEVELOPING. MOST LIKELY
AREAS WILL BE RKD...LEB...AND AUG...HOWEVER...PATCHY FOG IN OTHER
AREAS MAY ALSO BE POSSIBLE.
PREVIOUS DISCUSSION...VFR THROUGH SUN NIGHT.
LONG TERM...VFR.
&&
.MARINE...
SHORT TERM...NO FLAGS ATTM...BUT WILL SEE SW FLOW APPROACH SCA
LVLS SUN EVENING IN ADVANCE OF A COLD FRONT.
LONG TERM...WAVES APPROACH 5-6 FT TUESDAY NIGHT INTO THU AS A LOW
PRESSURE SYSTEM PASSES WELL SOUTH OF NEW ENGLAND.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...KISTNER
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
945 PM EST SAT DEC 5 2015
.SYNOPSIS...
AREAS OF DENSE FOG WILL PLAGUE PARTS OF THE REGION THROUGH SUNDAY
MORNING. OTHERWISE...HIGH PRESSURE WILL MAINTAIN PRECIPITATION
FREE WEATHER WITH MODERATING TEMPERATURES.
&&
.NEAR TERM /THROUGH SUNDAY/...
NO CHANGES WERE NEEDED FOR THE LATE EVE UPDATE.
PREVIOUS...
THE EARLY EVE UPDATE FEATURED A DENSE FOG ADVISORY ISSUANCE FOR AREAS
NORTH AND WEST OF PITTSBURGH WHERE DEEPER BOUNDARY LAYER MOISTURE AND
NO SFC WIND UNDER A STRONG INVERSION PROMISE TO SUPPORT FAIRLY
WIDESPREAD DENSE FOG...MUCH LIKE THIS MORNING.
THEREAFTER...SFC HIGH PRESSURE WILL SHIFT NEWD ON SUNDAY...WITH LIGHT
SWLY WIND DVLPG WARM ADVECTION. OUTSIDE OF ANY AREAS OF LINGERING
FOG...TEMPS ARE PROJECTED ABOUT 10 DEGREES ABOVE THE AVGS.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH MONDAY/...
UPPER TROUGH AND ASSOCIATED SURFACE LOW WILL CROSS THE OHIO VALLEY
ON MONDAY. WITH THE SYSTEM RELATIVELY STACKED...MOST OF THE
MOISTURE AND LIFT WILL REMAIN JUST SOUTH OF THE FORECAST AREA.
HOWEVER...WEAK COLD ADVECTION WITH THE TROUGHS DEPARTURE MAY
SUPPORT LINGERING PRECIPITATION IN THE RIDGES. WITH THIS IN
MIND...AND SOME CONSISTENCY IN THE MODELS...HAVE REINTRODUCED
CHANCE POPS INTO THE FORECAST THROUGH MONDAY NIGHT.
ANOTHER SHORTWAVE...QUICKLY ON THE HEELS OF THE DEPARTING
SYSTEM...WILL CROSS LATER ON TUESDAY BUT AGAIN...MOISTURE IS
LIMITED. AT THIS POINT WILL JUST HOLD SOME CLOUDS ACROSS THE
REGION WITH A SURFACE RIDGE IN PLACE. TEMPERATURES BOTH DAYS WERE
HELD NEAR CLIMATOLOGICAL NORMALS WITH CLOUD COVER.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
UPPER LEVEL PATTERN WILL CONTINUE TO SUPPORT FAST MOVING
SHORTWAVES UNTIL LATE IN THE WEEK WHEN AMPLIFICATION OF THE
TROUGH OVER THE WESTERN CONUS SUPPORTS RIDGING IN THE EAST. THERE
ARE SOME STRENGTH AND TIMING DIFFERENCES EVIDENT BETWEEN THE
GFS...ECMWF...AND OTHER MODEL GUIDANCE FOR A LATE WEAK LOW
PRESSURE SYSTEM SO VERY LOW CHANCE POPS WERE MAINTAINED.
UPPER RIDGING WILL SUPPORT MODERATING TEMPERATURES TO WELL ABOVE
SEASONAL AVERAGES BY SATURDAY.
&&
.AVIATION /02Z SUNDAY THROUGH THURSDAY/...
THERE WILL BE A BRIEF PERIOD OF VFR CONDITIONS BEFORE LIGHT
WIND...RESIDUAL MOISTURE AND COOLING LEAD THE AIR MASS TO REACH
SATURATION AGAIN...ESPECIALLY IN RIVER VALLEYS. 00Z TAFS INCLUDE A
MIX OF A PERSISTENCE FORECAST FROM OBSERVATIONS OVER THE LAST 24
HOURS AND THE 20Z HRRR MODEL...WHICH HAD THE BEST SPATIAL COVERAGE
OF FOG COMPARED TO CURRENT SATELLITE IMAGERY. FOG IS CURRENTLY
PATCHY ACROSS EASTERN OHIO AND NORTHWESTERN PENNSYLVANIA...BUT
THIS FOG IS EXPECTED TO EXPAND SOUTH AND EAST IN COVERAGE THROUGH
THE NEXT SEVERAL HOURS. FOG IS LIKELY TO PERSIST INTO SUNDAY
MORNING...IF NOT EARLY AFTERNOON. DISSIPATION TO VFR CONDITIONS
WILL BE AIDED BY SOUTHWEST WINDS DEVELOPING ON SUNDAY...COMPARED
TO THE NEAR CALM CONDITIONS WITH HIGH PRESSURE CURRENTLY ACROSS
THE REGION.
.OUTLOOK...SUNDAY NIGHT THROUGH THURSDAY/...
VFR CONDITIONS ARE EXPECTED GENERALLY THROUGH THE PERIOD. LIGHT
RAIN MAY IMPACT KZZV/KMGW ON MONDAY AS AN UPPER-LEVEL DISTURBANCE
CROSSES THE REGION.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...DENSE FOG ADVISORY UNTIL 10 AM EST SUNDAY FOR OHZ039>041-
048>050-057-058-068.
PA...DENSE FOG ADVISORY UNTIL 10 AM EST SUNDAY FOR PAZ007>009-
013>016-020-022-023.
WV...DENSE FOG ADVISORY UNTIL 10 AM EST SUNDAY FOR WVZ001.
&&
$$
15/33
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
658 PM EST SAT DEC 5 2015
.SYNOPSIS...
AREAS OF DENSE FOG WILL PLAGUE THE REGION THROUGH SUNDAY MORNING.
OTHERWISE...HIGH PRESSURE WILL MAINTAIN PRECIPITATION FREE WEATHER
WITH MODERATING TEMPERATURES.
&&
.NEAR TERM /THROUGH SUNDAY/...
THE EARLY EVE UPDATE FEATURED A DENSE FOG ADVISORY ISSUANCE FOR AREAS
NORTH AND WEST OF PITTSBURGH WHERE DEEPER BOUNDARY LAYER MOISTURE AND
NO SFC WIND UNDER A STRONG INVERSION PROMISE TO SUPPORT FAIRLY
WIDESPREAD DENSE FOG...MUCH LIKE THIS MORNING.
THEREAFTER...SFC HIGH PRESSURE WILL SHIFT NEWD ON SUNDAY...WITH LIGHT
SWLY WIND DVLPG WARM ADVECTION. OUTSIDE OF ANY AREAS OF LINGERING
FOG...TEMPS ARE PROJECTED ABOUT 10 DEGREES ABOVE THE AVGS.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH MONDAY/...
UPPER TROUGH AND ASSOCIATED SURFACE LOW WILL CROSS THE OHIO VALLEY
ON MONDAY. WITH THE SYSTEM RELATIVELY STACKED...MOST OF THE
MOISTURE AND LIFT WILL REMAIN JUST SOUTH OF THE FORECAST AREA.
HOWEVER...WEAK COLD ADVECTION WITH THE TROUGHS DEPARTURE MAY
SUPPORT LINGERING PRECIPITATION IN THE RIDGES. WITH THIS IN
MIND...AND SOME CONSISTENCY IN THE MODELS...HAVE REINTRODUCED
CHANCE POPS INTO THE FORECAST THROUGH MONDAY NIGHT.
ANOTHER SHORTWAVE...QUICKLY ON THE HEELS OF THE DEPARTING
SYSTEM...WILL CROSS LATER ON TUESDAY BUT AGAIN...MOISTURE IS
LIMITED. AT THIS POINT WILL JUST HOLD SOME CLOUDS ACROSS THE
REGION WITH A SURFACE RIDGE IN PLACE. TEMPERATURES BOTH DAYS WERE
HELD NEAR CLIMATOLOGICAL NORMALS WITH CLOUD COVER.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
UPPER LEVEL PATTERN WILL CONTINUE TO SUPPORT FAST MOVING
SHORTWAVES UNTIL LATE IN THE WEEK WHEN AMPLIFICATION OF THE
TROUGH OVER THE WESTERN CONUS SUPPORTS RIDGING IN THE EAST. THERE
ARE SOME STRENGTH AND TIMING DIFFERENCES EVIDENT BETWEEN THE
GFS...ECMWF...AND OTHER MODEL GUIDANCE FOR A LATE WEAK LOW
PRESSURE SYSTEM SO VERY LOW CHANCE POPS WERE MAINTAINED.
UPPER RIDGING WILL SUPPORT MODERATING TEMPERATURES TO WELL ABOVE
SEASONAL AVERAGES BY SATURDAY.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
THERE WILL BE A BRIEF PERIOD OF VFR CONDITIONS BEFORE LIGHT
WIND...RESIDUAL MOISTURE AND COOLING LEAD THE AIR MASS TO REACH
SATURATION AGAIN...ESPECIALLY IN RIVER VALLEYS. 00Z TAFS INCLUDE A
MIX OF A PERSISTENCE FORECAST FROM OBSERVATIONS OVER THE LAST 24
HOURS AND THE 20Z HRRR MODEL...WHICH HAD THE BEST SPATIAL COVERAGE
OF FOG COMPARED TO CURRENT SATELLITE IMAGERY. FOG IS CURRENTLY
PATCHY ACROSS EASTERN OHIO AND NORTHWESTERN PENNSYLVANIA...BUT
THIS FOG IS EXPECTED TO EXPAND SOUTH AND EAST IN COVERAGE THROUGH
THE NEXT SEVERAL HOURS. FOG IS LIKELY TO PERSIST INTO SUNDAY
MORNING...IF NOT EARLY AFTERNOON. DISSIPATION TO VFR CONDITIONS
WILL BE AIDED BY SOUTHWEST WINDS DEVELOPING ON SUNDAY...COMPARED
TO THE NEAR CALM CONDITIONS WITH HIGH PRESSURE CURRENTLY ACROSS
THE REGION.
.OUTLOOK...SUNDAY NIGHT THROUGH THURSDAY/...
VFR CONDITIONS ARE EXPECTED GENERALLY THROUGH THE PERIOD. LIGHT
RAIN MAY IMPACT KZZV/KMGW ON MONDAY AS AN UPPER-LEVEL DISTURBANCE
CROSSES THE REGION.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...DENSE FOG ADVISORY UNTIL 10 AM EST SUNDAY FOR OHZ039>041-
048>050-057-058-068.
PA...DENSE FOG ADVISORY UNTIL 10 AM EST SUNDAY FOR PAZ007>009-
013>016-020-022-023.
WV...DENSE FOG ADVISORY UNTIL 10 AM EST SUNDAY FOR WVZ001.
&&
$$
15/33
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
534 PM EST FRI DEC 4 2015
.SYNOPSIS...
RIDGE OF HIGH PRESSURE WILL BRING DRY WEATHER AND SLOWLY
MODERATING TEMPERATURES THROUGH THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
WITH 530PM UPDATE...UPDATED HOURLY TEMPERATURE TRENDS AS WELL AS
SKY COVER. AS THE PREVIOUS DISCUSSION ALREADY MENTIONED...STRATUS
REMAINS OVER OHIO AND PENNSYLVANIA...BUT JUST OUTSIDE OF THE
FORECAST AREA. ALTHOUGH THE HRRR SHOWS THE STRATUS MOVING INTO THE
REGION AS IT CONTINUES TO BURN OFF...IT IS ALSO THE ONLY MODEL
THAT DEPICTS THE CLOUDS...SOMETHING THE OTHER MODELS ARE CLEARLY
FAILING ON. ESSENTIALLY WILL CONTINUE WITH THE PERSISTENCE
FORECAST. PREVIOUS DISCUSSION FOLLOWS.
MAINLY CLEAR SKIES ARE ANTICIPATED OVERNIGHT AS RIDGE OF HIGH
PRESSURE MOVES OVER THE REGION. THE HRRR MODEL SUGGESTS THAT
REMAINING STRATUS OVER OHIO THAT DOESN`T BURN OFF THIS AFTERNOON
MAY MOVE OVER THE REGION...BUT NOT CONFIDENT THAT THIS IS
REALISTIC SINCE THE BACK EDGE IS BURNING OFF RATHER QUICKLY. WITH
THIS IN MIND...EXPECT RADIATIONAL COOLING TO SUPPORT TEMPERATURES
IN THE 20`S CWA-WIDE.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/...
CLEAR AND DRY CONDITIONS WILL PERSIST THROUGH THE WEEKEND AS HIGH
PRESSURE SETTLES OVERHEAD. ALTHOUGH THERE WILL BE LITTLE
MIXING...ABUNDANT SUNSHINE AND WARMING MID LEVELS SHOULD SUPPORT
ABOVE NORMAL DAYTIME TEMPERATURES. NIGHTTIME TEMPERATURES
HOWEVER...SHOULD REMAIN NEAR NORMAL WITH STRONG RADIATIONAL
COOLING EXPECTED.
ON MONDAY...THE APPROACH OF AN UPPER TROUGH WILL BRING AN INCREASE
IN CLOUD COVER AND COOLER TEMPERATURES HOWEVER MOST OF THE
MOISTURE AND LIFT WILL REMAIN SOUTH...SO LOW CHANCE POPS WERE
CARRIED THROUGH THE END OF THE PERIOD.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
BLEND OF MODELS CONSISTENT IN MOVING LOW PRESSURE SOUTH AND EAST
OF REGION THROUGH TUESDAY KEEPING CLOUDS ACROSS THE REGION.
GENERAL ZONAL FLOW ALOFT WILL KEEP TEMPERATURES MILD THROUGH THE
EXTENDED PERIOD. HARD TO TIME SHORTWAVES IN FAST FLOW MAY BRING
A LOW CHANCE FOR SHOWERS LATE WEEK.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
MIXING UNDER HIGH PRESSURE WILL BRING GENERAL VFR WITH LIGHT WEST
WINDS INTO THE EVENING. MAINLY CLEAR WITH LIGHT WINDS OVERNIGHT.
.OUTLOOK...SATURDAY THROUGH WEDNESDAY/...
VFR CONDITIONS THROUGH THE PERIOD.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
309 PM EST FRI DEC 4 2015
.SYNOPSIS...
RIDGE OF HIGH PRESSURE WILL BRING DRY WEATHER AND SLOWLY
MODERATING TEMPERATURES THROUGH THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
MAINLY CLEAR SKIES ARE ANTICIPATED OVERNIGHT AS RIDGE OF HIGH
PRESSURE MOVES OVER THE REGION. THE HRRR MODEL SUGGESTS THAT
REMAINING STRATUS OVER OHIO THAT DOESN`T BURN OFF THIS AFTERNOON
MAY MOVE OVER THE REGION...BUT NOT CONFIDENT THAT THIS IS
REALISTIC SINCE THE BACK EDGE IS BURNING OFF RATHER QUICKLY. WITH
THIS IN MIND...EXPECT RADIATIONAL COOLING TO SUPPORT TEMPERATURES
IN THE 20`S CWA-WIDE.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/...
CLEAR AND DRY CONDITIONS WILL PERSIST THROUGH THE WEEKEND AS HIGH
PRESSURE SETTLES OVERHEAD. ALTHOUGH THERE WILL BE LITTLE
MIXING...ABUNDANT SUNSHINE AND WARMING MID LEVELS SHOULD SUPPORT
ABOVE NORMAL DAYTIME TEMPERATURES. NIGHTTIME TEMPERATURES
HOWEVER...SHOULD REMAIN NEAR NORMAL WITH STRONG RADIATIONAL
COOLING EXPECTED.
ON MONDAY...THE APPROACH OF AN UPPER TROUGH WILL BRING AN INCREASE
IN CLOUD COVER AND COOLER TEMPERATURES HOWEVER MOST OF THE
MOISTURE AND LIFT WILL REMAIN SOUTH...SO LOW CHANCE POPS WERE
CARRIED THROUGH THE END OF THE PERIOD.
&&
.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
BLEND OF MODELS CONSISTENT IN MOVING LOW PRESSURE SOUTH AND EAST
OF REGION THROUGH TUESDAY KEEPING CLOUDS ACROSS THE REGION.
GENERAL ZONAL FLOW ALOFT WILL KEEP TEMPERATURES MILD THROUGH THE
EXTENDED PERIOD. HARD TO TIME SHORTWAVES IN FAST FLOW MAY BRING
A LOW CHANCE FOR SHOWERS LATE WEEK.
&&
.AVIATION /20Z FRIDAY THROUGH WEDNESDAY/...
STRATUS STILL HOLDING ON AT KFKL BUT SHOULD MIX OUT BY 20Z OR SO.
OTHERWISE MIXING UNDER HIGH PRESSURE WILL BRING GENERAL VFR WITH
LIGHT WEST WINDS INTO THE EVENING. MAINLY CLEAR WITH LIGHT WINDS
OVERNIGHT.
.OUTLOOK...SATURDAY THROUGH TUESDAY/...
VFR CONDITIONS THROUGH THE PERIOD.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
115 PM EST FRI DEC 4 2015
.SYNOPSIS...
HIGH PRESSURE WILL BRING DRY WEATHER AND SLOWLY MODERATING
TEMPERATURES THROUGH THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
CURRENT SATELLITE REFLECTS THE HRRR MODEL FORECAST FROM THIS
MORNING. THUS...NO NEAR TERM CHANGES WERE NEEDED AS SUNSHINE AND
MIXING SHOULD CONTINUE TO BURN OFF STRATUS ACROSS THE WESTERNMOST
ZONES THROUGH EARLY AFTERNOON AND HIGH TEMPERATURES SHOULD REACH
OR EXCEED NORMAL VALUES.
MAINLY CLEAR SKIES ARE ANTICIPATED OVERNIGHT AS RIDGE OF HIGH
PRESSURE MOVES OVER THE REGION. THE HRRR MODEL SUGGESTS THAT
REMAINING STRATUS OVER OHIO THAT DOESN`T BURN OFF THIS AFTERNOON
MAY MOVE OVER THE REGION...BUT NOT CONFIDENT THAT THIS IS
REALISTIC SINCE THE BACK EDGE IS BURNING OFF RATHER QUICKLY. WITH
THIS IN MIND...EXPECT RADIATIONAL COOLING TO SUPPORT TEMPERATURES
IN THE 20`S CWA-WIDE.
&&
.SHORT TERM /SATURDAY THROUGH MONDAY/...
CLEAR AND DRY CONDITIONS WILL PERSIST THROUGH THE WEEKEND AS HIGH
PRESSURE SETTLES OVER THE REGION. ALTHOUGH THERE WILL BE LITTLE
MIXING...ABUNDANT SUNSHINE AND WARMING MID LEVELS SHOULD SUPPORT
ABOVE NORMAL DAYTIME TEMPERATURES. NIGHTTIME TEMPERATURES
HOWEVER...SHOULD REMAIN NEAR NORMAL WITH STRONG RADIATIONAL
COOLING EXPECTED.
ON MONDAY...THE APPROACH OF AN UPPER TROUGH WILL BRING AN INCREASE
IN CLOUD COVER AND COOLER TEMPERATURES HOWEVER MOST OF THE
MOISTURE AND LIFT WILL REMAIN SOUTH...SO LOW CHANCE POPS WERE
CARRIED THROUGH THE END OF THE PERIOD.
&&
.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
BLEND OF MODELS CONSISTENT IN MOVING LOW PRESSURE SOUTH AND EAST
OF REGION THROUGH TUESDAY KEEPING CLOUDS ACROSS THE REGION.
GENERAL ZONAL FLOW ALOFT WILL KEEP TEMPERATURES MILD THROUGH THE
EXTENDED PERIOD. HARD TO TIME SHORTWAVES IN FAST FLOW MAY BRING
A LOW CHANCE FOR SHOWERS LATE WEEK.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
STRATUS STILL HOLDING ON AT KFKL BUT SHOULD MIX OUT BY 20Z OR SO.
OTHERWISE MIXING UNDER HIGH PRESSURE WILL BRING GENERAL VFR WITH
LIGHT WEST WINDS INTO THE EVENING. MAINLY CLEAR WITH LIGHT WINDS
OVERNIGHT.
.OUTLOOK...SATURDAY THROUGH TUESDAY/...
VFR CONDITIONS THROUGH THE PERIOD.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1247 PM EST FRI DEC 4 2015
.SYNOPSIS...
HIGH PRESSURE WILL BRING DRY WEATHER AND SLOWLY MODERATING
TEMPERATURES THROUGH THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
MADE A NEAR TERM UPDATE TO SLIGHTLY ADJUST CLOUD COVER THROUGH THE
DAY BASED ON THE LATEST HI RES MODELS THAT SEEMED TO KEY ON THE
STRATUS OVER OHIO. WHILE THE HRRR SLIDES IT JUST INTO OUR
WESTERN-MOST ZONES...THAT APPEARS THAT WILL BE AS FAR AS IT GETS
BEFORE LOW LEVEL MIXING RESUMES AND SCATTERS OUT WHAT`S LEFT OF
THE CLOUD DECK OVER THE REGION.
TEMPERATURES WILL REMAIN RATHER STAGNANT UNTIL THE STRATUS
CLEARS. AFTER THAT TIME...SUFFICIENT INSOLATION SHOULD SUPPORT
HIGH TEMPERATURES JUST A TOUCH ABOVE NORMAL BY AFTERNOON.
CLEAR SKIES WILL CONTINUE INTO TONIGHT. DEWPOINTS WILL REMAIN LOW
AND SURFACE HIGH PRESSURE WILL MEANDER NEARBY. THIS SHOULD ALLOW
FOR FAIRLY EFFICIENT RADIATIONAL COOLING WITH WIDESPREAD LOWS IN
THE 20S.
&&
.SHORT TERM /SATURDAY THROUGH MONDAY/...
CLEAR AND DRY CONDITIONS WILL PERSIST THROUGH THE WEEKEND AS HIGH
PRESSURE SETTLES OVER THE REGION. UNDER ABUNDANT SUNSHINE...HIGH TEMPERATURES
WILL WARM THROUGH THE WEEKEND AS AXIS OF THE UPPER RIDGE SLOWLY
SHIFTS EAST AND CALM WINDS STIR FROM THE SOUTH. NIGHTTIME LOWS
WILL REMAIN NEAR OR JUST BELOW FREEZING AS THE CLEAR CONDITIONS
WILL LEAD TO RADIATIONAL COOLING AND DE-COUPLING OF THE LOWER
ATMOSPHERE. TAX
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
BLEND OF MODELS CONSISTENT IN MOVING LOW PRESSURE SOUTH AND EAST
OF REGION THROUGH TUESDAY KEEPING CLOUDS ACROSS THE REGION.
GENERAL ZONAL FLOW ALOFT WILL KEEP TEMPERATURES MILD THROUGH THE
EXTENDED PERIOD. HARD TO TIME SHORTWAVES IN FAST FLOW MAY BRING
A LOW CHANCE FOR SHOWERS LATE WEEK.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
STRATUS STILL HOLDING ON AT KFKL BUT SHOULD MIX OUT BY 20Z OR SO.
OTHERWISE MIXING UNDER HIGH PRESSURE WILL BRING GENERAL VFR WITH
LIGHT WEST WINDS INTO THE EVENING. MAINLY CLEAR WITH LIGHT WINDS
OVERNIGHT.
.OUTLOOK...SATURDAY THROUGH TUESDAY/...
VFR CONDITIONS THROUGH THE PERIOD.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS PITTSBURGH PA
914 AM EST FRI DEC 4 2015
.SYNOPSIS...
HIGH PRESSURE WILL BRING DRY WEATHER AND SLOWLY MODERATING
TEMPERATURES THROUGH THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
MADE A NEAR TERM UPDATE TO SLIGHTLY ADJUST CLOUD COVER THROUGH THE
DAY BASED ON THE LATEST HI RES MODELS THAT SEEMED TO KEY ON THE
STRATUS OVER OHIO. WHILE THE HRRR SLIDES IT JUST INTO OUR
WESTERN-MOST ZONES...THAT APPEARS THAT WILL BE AS FAR AS IT GETS
BEFORE LOW LEVEL MIXING RESUMES AND SCATTERS OUT WHAT`S LEFT OF
THE CLOUD DECK OVER THE REGION.
TEMPERATURES WILL REMAIN RATHER STAGNANT UNTIL THE STRATUS
CLEARS. AFTER THAT TIME...SUFFICIENT INSOLATION SHOULD SUPPORT
HIGH TEMPERATURES JUST A TOUCH ABOVE NORMAL BY AFTERNOON.
CLEAR SKIES WILL CONTINUE INTO TONIGHT. DEWPOINTS WILL REMAIN LOW
AND SURFACE HIGH PRESSURE WILL MEANDER NEARBY. THIS SHOULD ALLOW
FOR FAIRLY EFFICIENT RADIATIONAL COOLING WITH WIDESPREAD LOWS IN
THE 20S.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
CLEAR AND DRY CONDITIONS WILL PERSIST THROUGH THE WEEKEND AS HIGH
PRESSURE SETTLES OVER THE REGION. UNDER ABUNDANT SUNSHINE...HIGH TEMPERATURES
WILL WARM THROUGH THE WEEKEND AS AXIS OF THE UPPER RIDGE SLOWLY
SHIFTS EAST AND CALM WINDS STIR FROM THE SOUTH. NIGHTTIME LOWS
WILL REMAIN NEAR OR JUST BELOW FREEZING AS THE CLEAR CONDITIONS
WILL LEAD TO RADIATIONAL COOLING AND DE-COUPLING OF THE LOWER
ATMOSPHERE. TAX
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
WEAK AND RELATIVELY DRY LOW PRESSURE SYSTEM WILL MOVE THROUGH THE
PLAINS APPROACHING OUR REGION TOWARD THE LATTER PART OF THE
WEEKEND. WITH THE LOW FULLY DETACHING FROM THE UPPER-LEVEL STREAM
TO THE NORTH...THE TRACK CONTINUES TO TREND SOUTH OF THE FORECAST
AREA. LATEST MODEL GUIDANCE VERY QUICKLY TRANSLATES THE WAVE TO
THE COAST...PULLING THE MEAGER MOISTURE AWAY FROM THE FORECAST
AREA. POPS HAVE BEEN REDUCED MONDAY NIGHT INTO TUESDAY.
CONFIDENCE IN THE EXTENDED FORECAST BEGINS TO WANE THEREAFTER AS
LONG RANGE MODELS ARE HAVING A TOUGH TIME WITH TIMING AND
STRENGTH OF A MID-WEEK WAVE. THERE IS AT LEAST SOME AGREEMENT ON
THE DEEPENING OF A BROAD TROUGH OVER THE WESTERN CONUS IN THE
LATTER PART OF NEXT WEEK. THIS WILL KEEP TEMPERATURES ABOVE
SEASONAL AVERAGES.
TAX
LITTLE CHANGE TO THE EXTENDED FROM THE PREVIOUS FORECAST. HIGH
PRESSURE WILL KEEP DRY AND MILD CONDITIONS THROUGH MONDAY. BLEND
OF MODELS CONSISTENT IN MOVING A WEAK LOW SOUTH OF THE FORECAST
AREA MONDAY TRANSITIONING TO A COASTAL LOW TUESDAY. LIMITED
MOISTURE AVAILABILITY AND TRACK OF THE LOW WILL KEEP DEEP MOISTURE
WELL SOUTH AND EAST. WILL GO WITH MODEL TRENDS AND KEEP ONLY
SLIGHT CHANCE POPS FAR SOUTHEAST RIDGES TUESDAY. HIGH PRESSURE
THEN BRINGS MORE DRY AND MILD CONDITIONS INTO LATE WEEK.
&&
.AVIATION /14Z FRIDAY THROUGH TUESDAY/...
STRATUS HAS ALREADY CLEARED FROM KZZV...AND WILL LIKEWISE
PROGRESSIVELY DO SO AT ALL SITES EAST OF THERE THROUGH THE NEXT
FEW HOURS. STRATUS CLEARING WILL BECOME MORE RAPID AFTER SUNRISE.
ALL SITES WILL BE CLEAR BY AFTERNOON WITH VFR CONDITIONS. FRIES
.OUTLOOK...FRIDAY NIGHT THROUGH TUESDAY/...
VFR CONDITIONS THROUGH THE PERIOD.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
749 PM EST SAT DEC 5 2015
.UPDATE...
STEADY SATURATION OF THE NOCTURNALLY COOLING AND SUFFICIENTLY MOIST
SHALLOW SUB-500 FT LAYER AGAIN LEADING TO AN AGGRESSIVE EXPANSION IN
STRATUS/FOG POST-SUNSET. LATEST HRRR GUIDANCE CASTS LITTLE DOUBT
THAT CONTINUED CONDENSATION WITHIN THE NEAR SURFACE LAYER WILL MOVE
THIS PROCESS TOWARD A DENSE FOG SITUATION AS THE NIGHT WEARS ON. IN
LIGHT OF TRENDS IN OBSERVATIONAL/SATELLITE DATA THUS FAR...AND
EXPECTATIONS MOVING FORWARD...WILL GO AHEAD WITH A DENSE FOG
ADVISORY TO CAPTURE THE ENTIRE MORNING PERIOD. SOME UNCERTAINTY
YET AS POTENTIAL COVERAGE OF DENSE FOG ACROSS THE TRI-
CITIES...THIS QUESTION PRECLUDING A PROACTIVE HEADLINE ISSUANCE AT
THIS POINT ALONG THAT CORRIDOR.
&&
.AVIATION...ISSUED 626 PM EST SAT DEC 5 2015
EXTREMELY FAVORABLE ENVIRONMENT IN PLACE TO SUPPORT AN EXTENSIVE
EXPANSION OF FOG AND VERY LOW STRATUS THROUGH THE FIRST HALF OF THE
NIGHT. OBSERVATIONAL TRENDS ALREADY INDICATING A NORTHWEST
EXPANSION OF THE EXISTING NEAR SURFACE MOISTURE PLUME ACROSS THE
DETROIT CORRIDOR...WITH SUBSEQUENT EXPANSION RESULTING IN
DETERIORATING CONDITIONS OVER THE REMAINDER OF THE SE MICHIGAN
AIRSPACE THROUGH MIDNIGHT. HIGH LEVEL OF CONFIDENCE EXISTS IN SEEING
AN EXTENDED PERIOD OF LIFR CONDITIONS EMERGE FOR BOTH VSBY AND CIGS
AT ALL LOCATIONS DURING THE EARLY AND MID MORNING HOURS. LATEST
MODEL GUIDANCE POINTS TOWARD A SLOW BURN OFF OF THIS MOISTURE
CENTERED 16Z-17Z ON SUNDAY.
FOR DTW...HIGH CONFIDENCE IN SEEING A LONG DURATION OF LIFR
CONDITIONS ACROSS THE AIRSPACE RIGHT THROUGH THE MORNING PERIOD.
GREATEST WINDOW FOR CONDITIONS TO FALL BELOW 1/2 MILE AND/OR 200 FT
CENTERED 08Z-15Z.
//DTW THRESHOLD PROBABILITIES...
* HIGH CONFIDENCE CEILINGS WILL BE BELOW 5000 FT THROUGH SUNDAY
MORNING.
* MEDIUM IN VSBY/CIGS FALLING BELOW 1/2SM AND/OR 200 FT PRIOR TO
08Z...HIGH CONFIDENCE BETWEEN 08Z AND 15Z THIS MORNING.
&&
.PREV DISCUSSION...ISSUED 323 PM EST SAT DEC 5 2015
DISCUSSION...
SIGNIFICANT RIDGING ALOFT HAS SUPPORTED A VERY WARM LOWER AND MID
TROPOSPHERIC COLUMN ACROSS THE UPPER MIDWEST AND GREAT LAKES
REGIONS. THE CONSEQUENCE OF THIS MASS CONFIGURATION IS THE
PRODUCTION OF A VERY SHALLOW COOL LAYER AT THE SURFACE THAT CANNOT
MIX WITH THE SLIGHTLY ELEVATED WARM LATER DUE TO THE EXTREMELY
STABLE TRANSITION LAYER. THE MOISTURE CONTENT BELOW THIS STRONG
INVERSION IS REMAINING FAIRLY CONSTANT...SO IT SIMPLY GOES THROUGH A
CONDENSATION CYCLE DURING THE NOCTURNAL HOURS AND EVAPORATION DURING
THE DIURNAL WINDOW. GIVEN THE RATHER STEADY-STATE SURFACE RIDGING
AND LACK OF AIRMASS REPLACEMENT NEAR THE GROUND...THIS CYCLE WILL
CONTINUE CERTAINLY THROUGH TONIGHT AND INDICATIONS ARE AN ADDITIONAL
TWO MORE DAYS BEFORE MORE ROBUST SOUTHWESTERLY FLOW BECOMES
ESTABLISHED ON TUESDAY.
THE VERY SHALLOW NATURE OF THE COOL LAYER /SEE 12Z KDTX RAOB/ ALLOWS
FOR GREATER TRAPPING OF MOISTURE IN THE LOWER ELEVATION REGIONS OF
METRO DETROIT. HENCE...THAT AREA IS THE LAST TO SCOUR OUT THE FOG
AND LOW CLOUDS. THERE IS STILL AN OPPORTUNITY TO CATCH A GLIMPSE OF
THE SUN PRIOR TO SUNSET...BUT IT WILL NOT BE LONG LIVED. EXPECT FOG
FORMATION TO QUICKLY RESUME AFTER SUNSET AND QUICKLY FILL ACROSS
SOUTHEAST MICHIGAN ONCE AGAIN. HRRR AND HRRRX GUIDANCE HAS BEEN
RATHER SKILLFUL WITH TODAY/S EPISODE AND OFFER REASONABLE DEPICTIONS
FOR THE NOCTURNAL CYCLE ONCE AGAIN TONIGHT - THOUGH MAY BE A LITTLE
TOO PESSIMISTIC EARLY IN THE PROCESS. HOWEVER...THESE SITUATIONS ARE
ALL OR NOTHING ONCE DEVELOPMENT COMMENCES. DENSE FOG IS HIGHLY
LIKELY AGAIN TONIGHT...BUT THE TIMING OF ONSET IS IN QUESTION GIVEN
THE LINGERING LOW CLOUDS ACROSS METRO DETROIT AND SOME DEGREE OF
DEWPOINT SEPARATION IN THOSE LOCATIONS WHERE THE SUN HAS BEEN MORE
ACTIVE.
EQUALLY CHALLENGING WILL BE THE SPATIAL QUALITY OF THE FOG / STRATUS
FIELD. EXPECT THE GLACIAL RIDGE TO EXPERIENCE THE LEAST INFLUENCE
ONCE AGAIN AS ELEVATION INTO THE INVERSION LAYER WILL DIMINISH THE
MOISTURE QUALITY AND FOG PRODUCTION EFFICIENCY. WHILE THE LOWER
ELEVATIONS TO THE SOUTH SHOULD HAVE A SIMILAR OUTCOME AS
WITNESSED TODAY.
THE CLOUDS AND FOG WILL SLOWLY GIVE WAY TO SUN PRIOR TO MIDDAY ON
SUNDAY...WITH THE RIDGE LOCATIONS STARTING MUCH EARLIER. THE DELAYED
START TO INSOLATION WILL ONCE AGAIN KEEP TEMPS BELOW STATISTICAL
GUIDANCE...AND IF CLOUDS REFUSE TO BREAK...MUCH BELOW AS
DEMONSTRATED TODAY.
SURFACE HIGH PRESSURE WILL REMAIN OVER THE GREAT LAKES REGION ON
TUESDAY KEEPING SOUTHEAST MICHIGAN DRY. THIS HIGH WILL SLOWLY DRIFT
TOWARDS THE ATLANTIC COAST ON WEDNESDAY AS A SHORTWAVE TROUGH PIVOTS
THROUGH THE GREAT LAKES RESULTING IN A CHANCE OF RAIN SHOWERS ON
WEDNESDAY. WEAK SURFACE RIDGING WILL KEEP US DRY FOR WEDNESDAY NIGHT
HOWEVER A STRONGER LOW PRESSURE SYSTEM QUICKLY FOLLOWS ON THURSDAY.
BEST CHANCE OF PRECIP WITH THE LOW WILL BE ACROSS THE NORTHERN CWA.
A COLD FRONT TRACKS ACROSS THE SOUTHERN GREAT LAKES ON THURSDAY
NIGHT AND INTO FRIDAY BRINGING A BETTER CHANCE OF RAIN TO THE ENTIRE
CWA. A MORE ORGANIZED SURFACE LOW PRESSURE SYSTEM IS FORECASTED TO
IMPACT THE AREA NEXT WEEKEND...HOWEVER...MODEL TENDENCIES ARE
INCONSISTENT IN TIMING OF THIS SYSTEM AT THIS TIME. HAVE LEFT JUST
CHANCE POPS /30 TO 40 PERCENT/ IN THE FORECAST FOR NOW.
MARINE...
HIGH PRESSURE OVER THE OHIO VALLEY REGION WILL PERSIST THROUGH
THE WEEKEND KEEPING LIGHT SOUTHWESTERLY WINDS ACROSS HURON.
BY MID WEEK A STRONGER FRONT WILL APPROACH FROM THE WEST WITH
INCREASING SPEEDS. HOWEVER WITH UNSEASONABLY MILD AIR IN
PLACE...BOUNDARY LAYER MIXING WILL BE MINIMAL AND WINDS SHOULD
HAVE NO TROUBLE REMAINING SUB-GALE. FOR THE LONGER TERM, THE NEXT
MAJOR FRONTAL SYSTEM IS POSSIBLE NEXT WEEKEND AND COULD BRING
BRIEF GALES TO THE REGION.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...DENSE FOG ADVISORY FROM MIDNIGHT TONIGHT TO NOON EST SUNDAY FOR
MIZ049-054-060-061.
DENSE FOG ADVISORY UNTIL NOON EST SUNDAY FOR MIZ055-062-063-068>070-
075-076-082-083.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&
$$
UPDATE.......MR
AVIATION.....MR
DISCUSSION...MANN/RK
MARINE.......05
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
626 PM EST SAT DEC 5 2015
.AVIATION...
EXTREMELY FAVORABLE ENVIRONMENT IN PLACE TO SUPPORT AN EXTENSIVE
EXPANSION OF FOG AND VERY LOW STRATUS THROUGH THE FIRST HALF OF THE
NIGHT. OBSERVATIONAL TRENDS ALREADY INDICATING A NORTHWEST
EXPANSION OF THE EXISTING NEAR SURFACE MOISTURE PLUME ACROSS THE
DETROIT CORRIDOR...WITH SUBSEQUENT EXPANSION RESULTING IN
DETERIORATING CONDITIONS OVER THE REMAINDER OF THE SE MICHIGAN
AIRSPACE THROUGH MIDNIGHT. HIGH LEVEL OF CONFIDENCE EXISTS IN SEEING
AN EXTENDED PERIOD OF LIFR CONDITIONS EMERGE FOR BOTH VSBY AND CIGS
AT ALL LOCATIONS DURING THE EARLY AND MID MORNING HOURS. LATEST
MODEL GUIDANCE POINTS TOWARD A SLOW BURN OFF OF THIS MOISTURE
CENTERED 16Z-17Z ON SUNDAY.
FOR DTW...HIGH CONFIDENCE IN SEEING A LONG DURATION OF LIFR
CONDITIONS ACROSS THE AIRSPACE RIGHT THROUGH THE MORNING PERIOD.
GREATEST WINDOW FOR CONDITIONS TO FALL BELOW 1/2 MILE AND/OR 200 FT
CENTERED 08Z-15Z.
//DTW THRESHOLD PROBABILITIES...
* HIGH CONFIDENCE CEILINGS WILL BE BELOW 5000 FT THROUGH SUNDAY
MORNING.
* MEDIUM IN VSBY/CIGS FALLING BELOW 1/2SM AND/OR 200 FT PRIOR TO
08Z...HIGH CONFIDENCE BETWEEN 08Z AND 15Z THIS MORNING.
&&
.PREV DISCUSSION...ISSUED 323 PM EST SAT DEC 5 2015
DISCUSSION...
SIGNIFICANT RIDGING ALOFT HAS SUPPORTED A VERY WARM LOWER AND MID
TROPOSPHERIC COLUMN ACROSS THE UPPER MIDWEST AND GREAT LAKES
REGIONS. THE CONSEQUENCE OF THIS MASS CONFIGURATION IS THE
PRODUCTION OF A VERY SHALLOW COOL LAYER AT THE SURFACE THAT CANNOT
MIX WITH THE SLIGHTLY ELEVATED WARM LATER DUE TO THE EXTREMELY
STABLE TRANSITION LAYER. THE MOISTURE CONTENT BELOW THIS STRONG
INVERSION IS REMAINING FAIRLY CONSTANT...SO IT SIMPLY GOES THROUGH A
CONDENSATION CYCLE DURING THE NOCTURNAL HOURS AND EVAPORATION DURING
THE DIURNAL WINDOW. GIVEN THE RATHER STEADY-STATE SURFACE RIDGING
AND LACK OF AIRMASS REPLACEMENT NEAR THE GROUND...THIS CYCLE WILL
CONTINUE CERTAINLY THROUGH TONIGHT AND INDICATIONS ARE AN ADDITIONAL
TWO MORE DAYS BEFORE MORE ROBUST SOUTHWESTERLY FLOW BECOMES
ESTABLISHED ON TUESDAY.
THE VERY SHALLOW NATURE OF THE COOL LAYER /SEE 12Z KDTX RAOB/ ALLOWS
FOR GREATER TRAPPING OF MOISTURE IN THE LOWER ELEVATION REGIONS OF
METRO DETROIT. HENCE...THAT AREA IS THE LAST TO SCOUR OUT THE FOG
AND LOW CLOUDS. THERE IS STILL AN OPPORTUNITY TO CATCH A GLIMPSE OF
THE SUN PRIOR TO SUNSET...BUT IT WILL NOT BE LONG LIVED. EXPECT FOG
FORMATION TO QUICKLY RESUME AFTER SUNSET AND QUICKLY FILL ACROSS
SOUTHEAST MICHIGAN ONCE AGAIN. HRRR AND HRRRX GUIDANCE HAS BEEN
RATHER SKILLFUL WITH TODAY/S EPISODE AND OFFER REASONABLE DEPICTIONS
FOR THE NOCTURNAL CYCLE ONCE AGAIN TONIGHT - THOUGH MAY BE A LITTLE
TOO PESSIMISTIC EARLY IN THE PROCESS. HOWEVER...THESE SITUATIONS ARE
ALL OR NOTHING ONCE DEVELOPMENT COMMENCES. DENSE FOG IS HIGHLY
LIKELY AGAIN TONIGHT...BUT THE TIMING OF ONSET IS IN QUESTION GIVEN
THE LINGERING LOW CLOUDS ACROSS METRO DETROIT AND SOME DEGREE OF
DEWPOINT SEPARATION IN THOSE LOCATIONS WHERE THE SUN HAS BEEN MORE
ACTIVE.
EQUALLY CHALLENGING WILL BE THE SPATIAL QUALITY OF THE FOG / STRATUS
FIELD. EXPECT THE GLACIAL RIDGE TO EXPERIENCE THE LEAST INFLUENCE
ONCE AGAIN AS ELEVATION INTO THE INVERSION LAYER WILL DIMINISH THE
MOISTURE QUALITY AND FOG PRODUCTION EFFICIENCY. WHILE THE LOWER
ELEVATIONS TO THE SOUTH SHOULD HAVE A SIMILAR OUTCOME AS
WITNESSED TODAY.
THE CLOUDS AND FOG WILL SLOWLY GIVE WAY TO SUN PRIOR TO MIDDAY ON
SUNDAY...WITH THE RIDGE LOCATIONS STARTING MUCH EARLIER. THE DELAYED
START TO INSOLATION WILL ONCE AGAIN KEEP TEMPS BELOW STATISTICAL
GUIDANCE...AND IF CLOUDS REFUSE TO BREAK...MUCH BELOW AS
DEMONSTRATED TODAY.
SURFACE HIGH PRESSURE WILL REMAIN OVER THE GREAT LAKES REGION ON
TUESDAY KEEPING SOUTHEAST MICHIGAN DRY. THIS HIGH WILL SLOWLY DRIFT
TOWARDS THE ATLANTIC COAST ON WEDNESDAY AS A SHORTWAVE TROUGH PIVOTS
THROUGH THE GREAT LAKES RESULTING IN A CHANCE OF RAIN SHOWERS ON
WEDNESDAY. WEAK SURFACE RIDGING WILL KEEP US DRY FOR WEDNESDAY NIGHT
HOWEVER A STRONGER LOW PRESSURE SYSTEM QUICKLY FOLLOWS ON THURSDAY.
BEST CHANCE OF PRECIP WITH THE LOW WILL BE ACROSS THE NORTHERN CWA.
A COLD FRONT TRACKS ACROSS THE SOUTHERN GREAT LAKES ON THURSDAY
NIGHT AND INTO FRIDAY BRINGING A BETTER CHANCE OF RAIN TO THE ENTIRE
CWA. A MORE ORGANIZED SURFACE LOW PRESSURE SYSTEM IS FORECASTED TO
IMPACT THE AREA NEXT WEEKEND...HOWEVER...MODEL TENDENCIES ARE
INCONSISTENT IN TIMING OF THIS SYSTEM AT THIS TIME. HAVE LEFT JUST
CHANCE POPS /30 TO 40 PERCENT/ IN THE FORECAST FOR NOW.
MARINE...
HIGH PRESSURE OVER THE OHIO VALLEY REGION WILL PERSIST THROUGH
THE WEEKEND KEEPING LIGHT SOUTHWESTERLY WINDS ACROSS HURON.
BY MID WEEK A STRONGER FRONT WILL APPROACH FROM THE WEST WITH
INCREASING SPEEDS. HOWEVER WITH UNSEASONABLY MILD AIR IN
PLACE...BOUNDARY LAYER MIXING WILL BE MINIMAL AND WINDS SHOULD
HAVE NO TROUBLE REMAINING SUB-GALE. FOR THE LONGER TERM, THE NEXT
MAJOR FRONTAL SYSTEM IS POSSIBLE NEXT WEEKEND AND COULD BRING
BRIEF GALES TO THE REGION.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&
$$
AVIATION.....MR
DISCUSSION...MANN/RK
MARINE.......05
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1035 AM EST FRI DEC 4 2015
.UPDATE...
ISSUED AN UPDATE EARLIER TO WORK MORE CLOUD WORDING INTO THE
AFTERNOON HOURS. TIME OF YEAR AND LOW SOLAR ANGLE SUPPORTS THIS.
HOWEVER...LATEST SATELLITE TREND HAS BEEN SHOWING A THINNING AND
A GREATER TRANSPARENCY OF CLOUDS. EXPECT A VARIABLE SKY COVERAGE
BY NOON...BUT EXTREMELY SHALLOW LAYER OF SATURATION WILL MAKE IT
DIFFICULT TO NAIL DOWN THE CORRECT SKY COVER IN TEXT.
&&
.AVIATION...ISSUED 445 AM EST FRI DEC 4 2015
TIMING THE EXIT OF THE LOW CLOUDS WILL REMAIN THE MOST CHALLENGING
ASPECT OF THE TAFS. A LOWERING INVERSION HAS LED TO AN EXTENSIVE
AREA OF IFR CEILINGS ACROSS NRN INDIANA AND FAR SW LOWER MI...ON THE
DOORSTEP OF METRO DETROIT AS OF 0930Z. THE INFLUENCE OF THE WEST-
SOUTHWEST FLOW ACROSS LAKE MI MAY HOLD THE INVERSION BASE UP A
LITTLE HIGHER...THUS KEEPING CIGS ON THE LOW END OF THE MVFR RANGE.
WARMER AND DRIER LOW LEVEL AIR WILL SLOWLY WORK FROM W TO E ACROSS
THE AREA LATE THIS MORNING INTO THE AFTERNOON. THE LOW LEVEL FLOW
WILL ALSO BECOME MORE ANTICYCLONIC DURING THIS TIME PERIOD. THIS
WILL PLACE THE MOST PROBABLE TIME PERIOD FOR CLEARING DURING THE 17Z
TO 20Z TIME FRAME. THERE HAS HOWEVER BEEN SOME FAIRLY SIGNIFICANT
BREAKS ACROSS NE LOWER MI...AN AFFECT OF SOME ADDED DOWNSLOPE.
CONSIDERING THE VERY SHALLOW NATURE OF THE MOISTURE. THIS DOWNSLOPE
MAY LEAD TO MORE BREAKS IN AND AROUND MBS MUCH EARLIER. ASIDE FROM
THE CLOUDS...WINDS HAVE ACTUALLY INCREASED OVERNIGHT /GUSTING UP TO
20 KNOTS AT TIMES/. THERE WILL BE A SLOW BUT STEADY DECREASE IN THE
WINDS DURING THE MORNING AND AFTERNOON AS THE GRADIENT WEAKENS.
FOR DTW....ANY CLEARING AT METRO PRIOR TO 18Z WILL NEED SOME MORNING
BREAKS TO DEVELOP OVER NRN IND/SW LOWER MI. RECENT SATELLITE TRENDS
SUGGEST THIS IS NOT GOING TO HAPPEN. IN FACT...THE HRRR KEEPS THE
CLOUDS IN THROUGH 21Z. WHILE CERTAINLY POSSIBLE...AT THIS TIME THE
CONCERNS OF EARLIER CLEARING UPSTREAM SUGGESTS ONLY PUSHING THE
CLEARING BACK TO 19Z.
//DTW THRESHOLD PROBABILITIES...
* HIGH FOR CEILINGS BELOW 5000 FEET THIS MORNING. LOW CONFIDENCE ON
TIMING OF CLEARING THIS AFTERNOON.
&&
.PREV DISCUSSION...ISSUED 237 AM EST FRI DEC 4 2015
DISCUSSION...
A LARGE AREA OF SURFACE HIGH PRESSURE WILL MAINTAIN QUIET WEATHER
THROUGH THE WEEKEND AS OVERALL MID LATITUDE FLOW REMAINS INNOCUOUS
FOR EARLY DECEMBER WITH AN EVEN WEAKER SUB-TROPICAL JET LENDING
LITTLE TO NO SUPPORT FOR ANY NOTABLE JET STREAM PHASING INTO EARLY
NEXT WEEK. THIS WILL LEAD TO A LARGELY DRY WEATHER PATTERN. THE NEXT
VERY SMALL CHANCE OF RAIN WILL COME EARLY NEXT WEEK AS A SHORTWAVE
MEANDERS EASTWARD INTO THE OHIO VALLEY. THIS SYSTEM REMAINS CUT OFF
FROM THE MAIN BAND OF WESTERLIES WITH NO INDICATIONS OF PHASING WITH
THE SUB-TROPICAL JET UNTIL IT APPROACHES THE EAST COAST. SO...ANY
PRECIPITATION THAT MAY BRUSH THE AREA IS EXPECTED TO BE TRIVIAL AT
THIS TIME.
FOR TODAY...SKY CONDITIONS WILL BE THE MAIN CHALLENGE AS CLEARING
WITHIN SUBSIDENCE REGION IN WAKE OF PASSING WEAK TROUGH HAS BEEN
SLOW TO OCCUR GIVEN THE REFORMATION OF STRATUS TO THE LEE OF LAKE
MICHIGAN. AS DRIER AIR CONTINUES TO WORK INTO AREA WITH EXPANDING
SURFACE HIGH PRESSURE...STILL EXPECT SKIES TO CLEAR WITH TIME DURING
THE DAY. IT JUST MAY TAKE HALF OR MORE OF THE DAY. THIS WILL HAVE
SOME AFFECT ON TEMPERATURES...ALTHOUGH STEADY WEST TO SOUTHWEST FLOW
WILL ALLOW FOR DECENT MIXING...SO EXPECT HIGHS TO CLIMB INTO THE MID
TO UPPER 40S AS A WEAK WARM AIR ADVECTION PATTERN ENSUES AS UPPER
RIDGING EXPANDS OVER THE AREA.
MILD WEATHER WILL PERSIST THROUGH THE WEEKEND AS THIS RIDGE SLOWLY
PROGRESSES TO THE EAST COAST...BUT AREA REMAINS WITHIN SOUTHWESTERLY
UPPER LEVEL FLOW. EXPECT HIGHS IN THE MID 40S TO AROUND 50 BOTH
DAYS.
WHILE THE ABOVE AVERAGE START TO DECEMBER WILL PERSIST THROUGH MID
TO LATE NEXT WEEK...OVERALL WEATHER PATTERN BECOMES INCREASINGLY
DIFFICULT AS THE MID LATITUDE JET STREAM COMING ONSHORE OVER THE
WESTERN CONUS INCREASES SUBSTANTIALLY WITH TIME NEXT WEEK. COUPLE
THIS WITH AN GRADUAL ENHANCEMENT IN THE SUBTROPICAL JET...AND ANY
SHORTWAVE ENERGY EJECTING INTO THE PLAINS/MIDWEST WILL HAVE A MUCH
BETTER CHANCE OF DEVELOPING INTO A DECENT STORM AS COMPARED TO THE
SHORTER TERM UPPER LEVEL CONDITIONS ACROSS THE CONUS THROUGH THE
WEEKEND.
MARINE...
A TIGHTENING OF THE GRADIENT OVER LAKE HURON THIS MORNING HAS LED TO
SOME GUSTY WEST-SOUTHWEST WINDS...GUSTING OVER 25 KNOTS AT TIMES. A
SURFACE TROUGH AXIS NOW ROTATING ACROSS THE NORTHERN GREAT
LAKES...PASSING ATOP THE NORTHERN PERIPHERY OF STRONG HIGH PRESSURE
CENTERED OVER THE MID MISSISSIPPI VALLEY...IS SUSTAINING THIS GRADIENT.
THIS TROUGH AXIS WILL TRACK EAST OF THE REGION TODAY. THE SURFACE
HIGH WILL THEN EXPAND NORTHWARD INTO THE GREAT LAKES. THIS ALONG
WITH LOW LEVEL WARM AIR ADVANCING ACROSS THE LAKES WILL LEAD TO A
STEADY DECREASING TREND IN WINDS AND WAVES TODAY. THE HIGH WILL
DRIFT TO THE MID ATLANTIC DURING THE COURSE OF THE WEEKEND...PLACING
LAKE HURON WITHIN A SOUTH-SOUTHWESTERLY RETURN FLOW. THE WARM LOW
LEVEL AIR WILL HINDER MIXING POTENTIAL OVER THE LAKES...SO GUSTS ARE
EXPECTED TO REMAIN LARGELY UNDER 20 KNOTS. HIGH PRESSURE WILL EXPAND
BACK ACROSS THE GREAT LAKES EARLY NEXT WEEK...PROVIDING FAIRLY LIGHT
WINDS MONDAY INTO AT LEAST TUESDAY.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&
$$
UPDATE.......CB
AVIATION.....SC
DISCUSSION....DG
MARINE.......SC
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
445 AM EST FRI DEC 4 2015
.AVIATION...
TIMING THE EXIT OF THE LOW CLOUDS WILL REMAIN THE MOST CHALLENGING
ASPECT OF THE TAFS. A LOWERING INVERSION HAS LED TO AN EXTENSIVE
AREA OF IFR CEILINGS ACROSS NRN INDIANA AND FAR SW LOWER MI...ON THE
DOORSTEP OF METRO DETROIT AS OF 0930Z. THE INFLUENCE OF THE WEST-
SOUTHWEST FLOW ACROSS LAKE MI MAY HOLD THE INVERSION BASE UP A
LITTLE HIGHER...THUS KEEPING CIGS ON THE LOW END OF THE MVFR RANGE.
WARMER AND DRIER LOW LEVEL AIR WILL SLOWLY WORK FROM W TO E ACROSS
THE AREA LATE THIS MORNING INTO THE AFTERNOON. THE LOW LEVEL FLOW
WILL ALSO BECOME MORE ANTICYCLONIC DURING THIS TIME PERIOD. THIS
WILL PLACE THE MOST PROBABLE TIME PERIOD FOR CLEARING DURING THE 17Z
TO 20Z TIME FRAME. THERE HAS HOWEVER BEEN SOME FAIRLY SIGNIFICANT
BREAKS ACROSS NE LOWER MI...AN AFFECT OF SOME ADDED DOWNSLOPE.
CONSIDERING THE VERY SHALLOW NATURE OF THE MOISTURE. THIS DOWNSLOPE
MAY LEAD TO MORE BREAKS IN AND AROUND MBS MUCH EARLIER. ASIDE FROM
THE CLOUDS...WINDS HAVE ACTUALLY INCREASED OVERNIGHT /GUSTING UP TO
20 KNOTS AT TIMES/. THERE WILL BE A SLOW BUT STEADY DECREASE IN THE
WINDS DURING THE MORNING AND AFTERNOON AS THE GRADIENT WEAKENS.
FOR DTW....ANY CLEARING AT METRO PRIOR TO 18Z WILL NEED SOME MORNING
BREAKS TO DEVELOP OVER NRN IND/SW LOWER MI. RECENT SATELLITE TRENDS
SUGGEST THIS IS NOT GOING TO HAPPEN. IN FACT...THE HRRR KEEPS THE
CLOUDS IN THROUGH 21Z. WHILE CERTAINLY POSSIBLE...AT THIS TIME THE
CONCERNS OF EARLIER CLEARING UPSTREAM SUGGESTS ONLY PUSHING THE
CLEARING BACK TO 19Z.
//DTW THRESHOLD PROBABILITIES...
* HIGH FOR CEILINGS BELOW 5000 FEET THIS MORNING. LOW CONFIDENCE ON
TIMING OF CLEARING THIS AFTERNOON.
&&
.PREV DISCUSSION...ISSUED 237 AM EST FRI DEC 4 2015
DISCUSSION...
A LARGE AREA OF SURFACE HIGH PRESSURE WILL MAINTAIN QUIET WEATHER
THROUGH THE WEEKEND AS OVERALL MID LATITUDE FLOW REMAINS INNOCUOUS
FOR EARLY DECEMBER WITH AN EVEN WEAKER SUB-TROPICAL JET LENDING
LITTLE TO NO SUPPORT FOR ANY NOTABLE JET STREAM PHASING INTO EARLY
NEXT WEEK. THIS WILL LEAD TO A LARGELY DRY WEATHER PATTERN. THE NEXT
VERY SMALL CHANCE OF RAIN WILL COME EARLY NEXT WEEK AS A SHORTWAVE
MEANDERS EASTWARD INTO THE OHIO VALLEY. THIS SYSTEM REMAINS CUT OFF
FROM THE MAIN BAND OF WESTERLIES WITH NO INDICATIONS OF PHASING WITH
THE SUB-TROPICAL JET UNTIL IT APPROACHES THE EAST COAST. SO...ANY
PRECIPITATION THAT MAY BRUSH THE AREA IS EXPECTED TO BE TRIVIAL AT
THIS TIME.
FOR TODAY...SKY CONDITIONS WILL BE THE MAIN CHALLENGE AS CLEARING
WITHIN SUBSIDENCE REGION IN WAKE OF PASSING WEAK TROUGH HAS BEEN
SLOW TO OCCUR GIVEN THE REFORMATION OF STRATUS TO THE LEE OF LAKE
MICHIGAN. AS DRIER AIR CONTINUES TO WORK INTO AREA WITH EXPANDING
SURFACE HIGH PRESSURE...STILL EXPECT SKIES TO CLEAR WITH TIME DURING
THE DAY. IT JUST MAY TAKE HALF OR MORE OF THE DAY. THIS WILL HAVE
SOME AFFECT ON TEMPERATURES...ALTHOUGH STEADY WEST TO SOUTHWEST FLOW
WILL ALLOW FOR DECENT MIXING...SO EXPECT HIGHS TO CLIMB INTO THE MID
TO UPPER 40S AS A WEAK WARM AIR ADVECTION PATTERN ENSUES AS UPPER
RIDGING EXPANDS OVER THE AREA.
MILD WEATHER WILL PERSIST THROUGH THE WEEKEND AS THIS RIDGE SLOWLY
PROGRESSES TO THE EAST COAST...BUT AREA REMAINS WITHIN SOUTHWESTERLY
UPPER LEVEL FLOW. EXPECT HIGHS IN THE MID 40S TO AROUND 50 BOTH
DAYS.
WHILE THE ABOVE AVERAGE START TO DECEMBER WILL PERSIST THROUGH MID
TO LATE NEXT WEEK...OVERALL WEATHER PATTERN BECOMES INCREASINGLY
DIFFICULT AS THE MID LATITUDE JET STREAM COMING ONSHORE OVER THE
WESTERN CONUS INCREASES SUBSTANTIALLY WITH TIME NEXT WEEK. COUPLE
THIS WITH AN GRADUAL ENHANCEMENT IN THE SUBTROPICAL JET...AND ANY
SHORTWAVE ENERGY EJECTING INTO THE PLAINS/MIDWEST WILL HAVE A MUCH
BETTER CHANCE OF DEVELOPING INTO A DECENT STORM AS COMPARED TO THE
SHORTER TERM UPPER LEVEL CONDITIONS ACROSS THE CONUS THROUGH THE
WEEKEND.
MARINE...
A TIGHTENING OF THE GRADIENT OVER LAKE HURON THIS MORNING HAS LED TO
SOME GUSTY WEST-SOUTHWEST WINDS...GUSTING OVER 25 KNOTS AT TIMES. A
SURFACE TROUGH AXIS NOW ROTATING ACROSS THE NORTHERN GREAT
LAKES...PASSING ATOP THE NORTHERN PERIPHERY OF STRONG HIGH PRESSURE
CENTERED OVER THE MID MISSISSIPPI VALLEY...IS SUSTAINING THIS GRADIENT.
THIS TROUGH AXIS WILL TRACK EAST OF THE REGION TODAY. THE SURFACE
HIGH WILL THEN EXPAND NORTHWARD INTO THE GREAT LAKES. THIS ALONG
WITH LOW LEVEL WARM AIR ADVANCING ACROSS THE LAKES WILL LEAD TO A
STEADY DECREASING TREND IN WINDS AND WAVES TODAY. THE HIGH WILL
DRIFT TO THE MID ATLANTIC DURING THE COURSE OF THE WEEKEND...PLACING
LAKE HURON WITHIN A SOUTH-SOUTHWESTERLY RETURN FLOW. THE WARM LOW
LEVEL AIR WILL HINDER MIXING POTENTIAL OVER THE LAKES...SO GUSTS ARE
EXPECTED TO REMAIN LARGELY UNDER 20 KNOTS. HIGH PRESSURE WILL EXPAND
BACK ACROSS THE GREAT LAKES EARLY NEXT WEEK...PROVIDING FAIRLY LIGHT
WINDS MONDAY INTO AT LEAST TUESDAY.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...SMALL CRAFT ADVISORY UNTIL 8 AM EST THIS MORNING FOR LHZ421-441.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&
$$
AVIATION.....SC
DISCUSSION....DG
MARINE.......SC
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
322 PM CST FRI DEC 4 2015
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 323 PM CST FRI DEC 4 2015
SOUTHWEST FLOW WILL CONTINUE TO BRING SEASONABLY WARM
TEMPERATURES ACROSS THE UPPER MIDWEST. THE MAIN CONCERN IS THE
WIND POTENTIAL ON THE LEE SIDE OF THE BUFFALO RIDGE ACROSS FAR
WESTERN MN. A FEW OF THE HIRES MODELS SHOW GUST NEAR 50KTS...BUT
THOSE MODELS ARE CURRENTLY OVER DOING THE WINDS ACROSS THE
DAKOTAS. BUFR SOUNDINGS OFF THE RAP AND HRRR KEEP THE WINDS ABOVE
THE BOUNDARY LAYER. WITH THAT SAID...COULD SEE 35-40KT GUSTS LATE
TONIGHT AS WINDS CROSS THE RIDGE...AND MAY NEED A WIND HEADLINE
TONIGHT FOR YELLOW MEDICINE OR LAC QUI PARLE COUNTIES IF THE WINDS
ARE ABLE TO BREAK THROUGH THE INVERSION DOWN TO THE SURFACE.
CONFIDENCE WAS TOO LOW TO ISSUE ONE AT THIS TIME.
A NARROW LONG WAVE TROUGH WILL APPROACH THE REGION FROM THE WEST
LATE SATURDAY. EXPECT CLOUDS TO INCREASE IN RESPONSE TO THIS
WAVE...AND FORECAST SOUNDINGS SHOW SOME DRIZZLE/SPRINKLES POSSIBLE
AS WELL. SATURDAYS TEMPS WILL BE SIMILAR TO TODAY...WITH MID 40S
COMMON ACROSS THOSE AREAS THAT DO NOT HAVE SNOW COVER.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 323 PM CST FRI DEC 4 2015
CONTINUANCE OF ABOVE NORMAL TEMPERATURES AND DRY WEATHER WILL
DESCRIBE THE BULK OF THE LONG TERM PERIOD.
TO START OFF THE PERIOD HOWEVER...A WEAK COLD FRONT WILL BE
TRACKING ACROSS THE AREA ON SATURDAY NIGHT. ASSOCIATED MOISTURE
AND FORCING ARE NEGLIGIBLE...SO EXPECT ANY RESULTANT PRECIP TO BE
MOSTLY IN THE FORM OF DRIZZLE. ABSENCE OF MOISTURE IN THE
DENDRITIC LAYER SHOULD MEAN THE PRECIP WILL BE OF THE LIQUID
VARIETY.
SUNDAY INTO THE UPCOMING WEEK FEATURES THE PERSISTENCE OF MID
LEVEL RIDGING...WITH TEMPERATURES AVERAGING 12-18 DEGREES ABOVE
CLIMATOLOGICAL NORMALS.
WHILE THE MAJORITY OF NEXT WEEK LOOKS DRY AND WARM...THE RIDGE
DOES LOOK TO BREAK DOWN LATE IN THE WEEK. THERE ARE STILL NOTABLE
DIFFERENCES BETWEEN THE GFS AND ECMWF...BUT THERE WOULD LIKELY BE
ANOTHER UPTICK IN TEMPERATURES AHEAD OF THE SYSTEM TOWARD THE END
OF THE WEEK FOLLOWED BY RAIN/SNOW CHANCES FRIDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1200 PM CST FRI DEC 4 2015
VFR CONDITIONS WILL GIVE WAY TO MVFR/IFR CEILINGS LATER TONIGHT
AND ON SATURDAY. A FEW RAIN SHOWERS ARE POSSIBLE BUT THERE IS NOT
SUFFICIENT MOISTURE FOR WIDESPREAD PRECIPITATION. SOUTHERLY WINDS
WILL INCREASE AT THE SURFACE WITH GUSTS NEAR 20KTS...BUT MORE
IMPORTANTLY A LOW LEVEL JET WILL DEVELOP WITH 50KTS OF WIND AT
2000FT AGL...SO WIND SHEAR WILL ALSO BE AN ISSUE.
KMSP...
IN ADDITION TO THE GENERAL DISCUSSION ABOVE...FORECAST SOUNDINGS
SHOW LOW LEVEL MOISTURE LATER TONIGHT THROUGH SATURDAY...SO HAVE
GONE WITH MVFR CLOUDS DURING THIS PERIOD. LOW LEVEL WIND SHEAR IS
MORE SPEED RELATED THAN DIRECTIONAL.
/OUTLOOK FOR KMSP/
SAT NIGHT...VFR. SLGT CHC -RA LATE. WINDS SW 10-15 KTS GUSTING 20
KTS.
SUN...VFR. WINDS W TO SW 5 KTS.
MON...VFR. WINDS S 10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
&&
$$
SHORT TERM...JRB
LONG TERM...LS
AVIATION...JRB
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
906 PM CST SAT DEC 5 2015
.UPDATE:
Issued at 905 PM CST Sat Dec 5 2015
Visibilities have dropped recently at Effingham, Taylorville, and
Mt. Vernon; though they are not nearly as low as they were at this
time last night. Still expect visibilities to fall into the 1-3SM
range overnight and early Sunday over the Illinois counties. Also
still looks like light rain will move into central and northeast
Missouri on Sunday morning. Latest HRRR and RAP suggest that this
precipitation will not reach the area until mid morning so have
delayed the onset of the light rain by just a bit. Otherwise the
rest of the forecast still looks on track.
Britt
&&
.SHORT TERM: (Through Late Tonight)
Issued at 330 PM CST Sat Dec 5 2015
Upper level shortwave across the Central Plains will move toward the
lower Missouri and middle Mississippi River Valleys tonight. This
will cause a gradual increase in high and mid level clouds from the
west and a slight chance of light rain showers entering parts of
central Missouri by daybreak. Otherwise, last vestages of the
surface ridge to our east will contribute to another night of fog
development, especially across parts of south central and southwest
Illinois. Not sure if the fog will be as widespread or dense as the
past two mornings though as inversion should be weaker. It may be
that the fog remains confined to just the river valleys,
especially across the St. Louis Metropolitan Area.
CVKING
.LONG TERM: (Sunday through Next Saturday)
Issued at 330 PM CST Sat Dec 5 2015
Aforementioned shortwave should pass through the FA during the day
on Sunday. Models are in very good agreement with the speed of
this system, with trof axis near the MO/KS border at 12z
progressing to the lower Ohio River valley by 00z in the evening.
This mornings UA data indicates that AMS is extremely dry over the
central CONUS from the northern Plains into the Gulf coast, but
all of the guidance suggests a strong surge of lower level
moisture into the region ahead of the upper level system later
tonight and into Sunday. So in spite of the initially bone-dry
AMS, believe that the progged moisture return will be adequate
with the expected lift from shortwave to continue mention of light
rain across the CWA during the day, with the precip then winding
down east of the Mississippi River on Sunday evening. Have
generally gone with consensus of MOS PoPs...in the chance/slight
chance range.
The cloudiness associated with this system will likely make
Sunday`s high temps 5 to 10 degrees cooler than those of today
along and west of the Mississippi River.
However, more mild early December weather appears to be in the
offing for much of the upcoming work week, as a westerly flow
regime dominates across the CONUS. This pattern will keep the
colder air bottled up well to the north of the region, so
temperatures should remain well above early December averages and
have maintained going trends by skewing forecast towards the
warmer guidance. GFS would suggest very warm temps during the
latter half of the week, but did not go that extreme as there is
more than a little discrepancy between the GFS and ECMWF in the
intensity of the Thursday shortwave and the resultant temperature
advection associated with it.
Disturbances embedded in this zonal flow are progged to clip the
area about every 24 to 36 hours through Thursday, however with
such rapid movement believe that the moisture available to each
of these features will be fairly limited. This, combined with the
fact that the main dynamics will be over the upper Missouri and
upper Mississippi Valleys, should mean the rain threat in our FA
will remain quite low.
However this may change by the end of the forecast period, as
there is consensus in the medium range guidance that a much
deeper trof that forms over the western U.S. later in the work
week begins to push into the Plains. Some warm-advection driven
rain could threaten as early as Thursday night/Friday, but the
better chances should hold off until next Saturday, when upper
level dynamics associated with upper trof push into the mid-
Mississippi Valley.
Truett
&&
.AVIATION: (For the 00z TAFs through 00z Sunday Evening)
Issued at 514 PM CST Sat Dec 5 2015
A number of questions for the next 24 hrs. First, while some FG is
expected to develop across portions of IL, do not anticipate it
building as far W as this morning. Some river FG may develop and
impact SUS/CPS, but confidence remains low. Otherwise, an
approaching cdfnt may bring lower cigs and perhaps a brief
sprinkle or SHRA Sun mid-day and during the afternoon. Confidence
on timing of fropa is slightly above average, but confidence in
cigs associated with the fnt is low. Have kept cigs in MVFR range
for now and will see how events unfold overnight.
Tilly
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS BUFFALO NY
953 PM EST SAT DEC 5 2015
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO BRING DRY WEATHER SUNDAY THROUGH
TUESDAY ALTHOUGH LOW CLOUDS WILL LIMIT SUNSHINE AT TIMES. A SERIES
OF WEAK SYSTEMS WILL BRING A CHANCE OF A FEW LIGHT SHOWERS LATER IN
THE WEEK. TEMPERATURES WILL REMAIN WELL ABOVE NORMAL THROUGH THE
NEXT WEEK AND BEYOND.
&&
.NEAR TERM /THROUGH SUNDAY/...
FOG AND LOW STRATUS IS THE PRIMARY FORECAST CONCERN OVERNIGHT INTO
SUNDAY MORNING. A THICK AREA OF STRATUS EAST OF LAKE ONTARIO WILL
LIKELY REMAIN IN PLACE OVERNIGHT... WITH THE REST OF THE FORECAST
AREA AT RISK FOR FOG FORMATION. LOW LEVEL MOISTURE REMAINS LOCKED IN
PLACE THIS EVENING UNDER A STRONG SUBSIDENCE INVERSION PER 00Z BUF
SOUNDING AND RECENT AVIATION SOUNDINGS. THE CLEARING SKIES THIS
EVENING ACROSS WESTERN NY WILL LIKELY PROMOTE ADDITIONAL FOG AND
VERY LOW STRATUS DEVELOPMENT OVERNIGHT AS RADIATIONAL COOLING
QUICKLY RE-SATURATES THE LOW LEVELS.
EXPECT FOG AND STRATUS TO BEGIN TO REFORM BY LATE EVENING AND THEN
EXPAND TO COVER MUCH OF THE AREA BEFORE DAYBREAK SUNDAY. UNLIKE THE
PAST FEW DAYS...FOG MAY BE MORE OF AN ISSUE LATE TONIGHT AND SUNDAY
MORNING. 12Z AND 18Z NAM BUFKIT POINT SOUNDINGS SUGGEST THE
DEVELOPMENT OF A SURFACE BASED INVERSION...AND INITIALLY CLEAR SKIES
EARLY TONIGHT ALSO SUGGEST MORE OF A FOG SCENARIO.
FOG WAS WIDESPREAD AND DENSE THIS MORNING JUST UPSTREAM ACROSS MUCH
OF OHIO...LOWER MICHIGAN...AND INDIANA. A BACKWARDS TRAJECTORY
FORECAST FROM THE HYSPLIT MODEL SHOWS AIR ARRIVING IN BUFFALO AT 12Z
SUNDAY HAS ORIGINS ACROSS EASTERN OHIO AND CENTRAL LAKE ERIE...WHERE
DENSE FOG WAS FOUND THIS MORNING. GIVEN THE UPSTREAM TRENDS AND
FORECAST SOUNDINGS...EXPECT FOG AND STRATUS TO BECOME WIDESPREAD
AGAIN LATE TONIGHT.
THE HRRR AND NAM DO NOT COMPLETELY AGREE ON HOW THE FOG DEVELOPMENT
WILL EVOLVED... BUT THE GENERAL CONSUS SUPPORTS MUCH OF WESTERN NY
SEEING FOG DEVELOP OVERNIGHT. EXPECT ONE AREA OF TRUE RADIATION FOG
TO DEVELOP NORTHWARD FROM NW PA (WHERE 11-3.9 IMAGERY AND OBS SHOW
DENSE FOG CURRENTLY IN PLACE) INTO THE SOUTHERN TIER TONIGHT... WITH
MAINLY INTERIOR VALLEYS AND LOW-LYING LOCATIONS ALONG RIVER VALLEYS
DEVELOPING FOG. THE OTHER AREA OF FOG/LOW STRATUS SHOULD DEVELOP
EASTWARD OUT OF ONTARIO... WITH ADDED MOISTURE FROM LAKE ERIE AS THE
FLOW TURNS MORE SOUTHWESTERLY OVERNIGHT...ENHANCED BY THE DEVELOPING
LAKE BREEZE AND THE SURFACE HIGH SHIFTING EASTWARD. THUS THIS SHOULD
HELP TO SPREAD AREAS OF FOG FROM THE NIAGARA FRONTIER ACROSS THE
ROCHESTER.
THE ADDITIONAL WRINKLE IS THAT TEMPERATURES WILL BE NEAR OR JUST
BELOW FREEZING ACROSS INTERIOR AND RURAL LOCATIONS... AND THUS THERE
IS POTENTIAL FOR SOME PATCHY BLACK ICE FORMATION OVERNIGHT WHERE
DENSE FOG DEVELOPS.
SUNDAY EXPECT FOG AND LOW STRATUS TO HOLD STRONG THROUGH MUCH OF THE
MORNING BENEATH A STRONG SUBSIDENCE INVERSION. THE LOW CLOUDS SHOULD
THEN MIX OUT IN A SIMILAR FASHION TO TODAY WITH INCREASING AMOUNTS
OF SUNSHINE DURING THE AFTERNOON. MODEL GUIDANCE IS NOT HANDLING THE
FOG AND STRATUS POTENTIAL PARTICULARLY WELL. WITH THIS IN
MIND...HAVE FORECAST TEMPERATURES ABOVE GUIDANCE TONIGHT AND BELOW
GUIDANCE ON SUNDAY. THIS WILL TRANSLATE TO LOWS IN THE MID 30S ON
THE LAKE PLAINS AND UPPER 20S TO LOWER 30S ACROSS THE INTERIOR
SOUTHERN TIER AND LEWIS COUNTY. HIGHS ON SUNDAY SHOULD REACH THE
UPPER 40S TO LOWER 50S ACROSS LOWER ELEVATIONS ASSUMING THE FOG AND
STRATUS BURNS OFF BY MIDDAY.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/...
A ZONAL PACIFIC FLOW WILL BE FOUND STRETCHED ACROSS THE CONUS MUCH
OF NEXT WEEK. THIS WILL KEEP GENERALLY FAIR WEATHER IN PLACE WITH
TEMPERATURES RUNNING ON THE MILDER SIDE OF NORMAL FOR EARLY
DECEMBER. SURFACE RIDGING WILL EXTEND SOUTH FROM NORTH OF THE GREAT
LAKES WITH THE ONLY STORM SYSTEM EAST OF THE ROCKIES BEING A MID-
LEVEL CLOSED LOW THAT WILL PASS SOUTH OF OUR FORECAST AREA ACROSS
THE OHIO VALLEY MONDAY THEN OFF THE MID-ATLANTIC COAST ON TUESDAY.
SYNOPTIC LIFT AND MOISTURE WILL BE COLLOCATED WITH THIS LOW CENTER
WITH NO THREAT OF PRECIPITATION FOR OUR FORECAST AREA.
SUNDAY NIGHT...CLEAR TO PARTLY CLOUDY SKIES ACROSS WESTERN AND
CENTRAL NEW YORK WILL ALLOW GOOD RADIATIONAL COOLING AND THE
POTENTIAL FOR PATCHY RIVER VALLEY FOG IN THE SOUTHERN TIER. THIS
COULD MAKE FOR SOME SLICK ROADWAYS IN AREAS WHERE SURFACE TEMPS FALL
BELOW FREEZING. LOWS WILL RANGE FROM THE M30S NEAR THE LAKES TO THE
U20S IN THE SOUTHERN TIER VALLEYS.
MONDAY INTO TUESDAY HAVE LEANED ON THE 05/12Z NAM SHOWING A RETURN
OF LOW CLOUDS UNDER LIGHT NORTHERLY FLOW TRAPPING LAKE MOISTURE
BENEATH A 925MB SUBSIDENCE INVERSION. THE FORECAST CLOUD COVER HAS
THEREFORE BEEN INCREASED TO MOSTLY CLOUDY. THERE MAY ALSO BE A
POTENTIAL FOR SOME PATCHY DRIZZLE BUT CONFIDENCE IS TOO LOW AT THIS
TIME TO INCLUDE IN THE FORECAST.
UNDER A LIGHT NORTHERLY FLOW MONDAY TEMPERATURES WILL RUN CLOSER TO
NORMAL WITH HIGHS TOPPING OUT IN THE LOW 40S FOR MOST. WINDS VEER
AROUND TO THE SOUTH ON TUESDAY AHEAD OF A COLD FRONT/SURFACE TROUGH
CROSSING THE UPPER MIDWEST. TEMPERATURES WILL EDGE UP A LITTLE
WARMER WITH HIGHS RANGING IN THE L/M 40S. OVERNIGHT LOWS WILL
CONTINUE TO RANGE FROM THE M30S NEAR THE LAKES TO U20S WELL INLAND.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
A LOW AMPLITUDE PACIFIC FLOW WILL CONTINUE THROUGH MUCH OF THE REST
OF NEXT WEEK WITH MEDIUM RANGE MODELS THEN INDICATING A POTENTIAL
FOR A MORE AMPLIFIED 500MB PATTERN GOING INTO NEXT WEEKEND WHICH
WOULD BRING WELL ABOVE NORMAL WARMTH.
05/12Z GFS AND ECMWF OPERATIONAL MODELS ALONG WITH GEFS ENSEMBLES
CONTINUE TO SHOW DISAGREEMENT IN THE 500MB PATTERN FOR WEDNESDAY AND
THURSDAY. EACH MODEL/MEMBER IS SHOWING DIFFERENCE IN TIMING AND
LOCATION OF SUBTLE SHORTWAVE TROUGHS MOVING ACROSS THE CONUS. THIS
CONTINUES TO MAKE FOR A LOW CONFIDENCE FORECAST OF ANY MINOR
PRECIPITATION EVENTS AS THESE SHORTWAVES CROSS THE EASTERN GREAT
LAKES. WILL CONTINUE SLIGHT/LOW CHANCE POPS FOR SHOWERS WEDNESDAY
INTO THURSDAY UNTIL CONFIDENCE IN TIMING AND LOCATION INCREASES.
THE PATTERN LOOKS TO AMPLIFY GOING INTO THE WEEKEND WHICH ALSO
LEADS TO A BETTER POTENTIAL FOR MORE SIGNIFICANT WEATHER ALTHOUGH
TIMING BETWEEN THE MODELS REMAINS MISALIGNED. THIS WILL KEEP SLIGHT
CHANCE POPS INTO THE WEEKEND. BETTER CONFIDENCE IS FOUND IN THE
POTENTIAL FOR AN AMPLIFIED RIDGE TO BUILD OVER THE EASTERN STATES
THIS WEEKEND. WHILE PACIFIC FLOW ALOFT AND SOUTHERLY SURFACE WINDS
WILL HELP BOOST TEMPS TOWARD 50 THURSDAY AND FRIDAY...AN AMPLIFIED
500MB RIDGE /IN WHICH NAEFS ENSEMBLES BUILD OVER +2SD/ WOULD MAKE
60S A POSSIBILITY FOR THE WEEKEND.
LOOKING FURTHER OUT INTO THE SECOND FULL WEEK OF DECEMBER...BOTH
THE ECMWF AND GFS BASED ENSEMBLES ARE IN STRONG AGREEMENT THAT THE
PACIFIC BASED FLOW COULD TEMPORARILY BREAK DOWN OVER THE LOWER 48.
A NICE SIZED CHUNK OF -12 TO -16C H85 AIR IS ADVERTISED TO MOVE
FROM THE CANADIAN PRAIRIES INTO THE UPPER MISSISSIPPI VALLEY.
SHOULD THIS AIRMASS MAKE IT TO THE OHIO VALLEY...IT WOULD BE IN A
FAVORABLE POSITION TO EVENTUALLY GENERATE SOME SIGNIFICANT LAKE
SNOWS EAST OF BOTH LAKES ERIE AND ONTARIO. THERE ARE PLENTY OF `IFS`
WITH THIS SCNEARIO THOUGH...BUT IT WILL BE INTERESTING TO KEEP AN
EYE ON AS WE MOVE DEEPER INTO PREPARATIONS FOR THE UPCOMING
HOLIDAY SEASON.
&&
.AVIATION /03Z SUNDAY THROUGH THURSDAY/...
MVFR STRATUS WILL PERSIST EAST OF LAKE ONTARIO TONIGHT AND INTO
SUNDAY...WITH SOME PATCH FOG DEVELOPMENT POSSIBLE LATER TONIGHT.
ACROSS WESTERN NY... CLEAR VFR SKIES THIS EVENING SHOULD ALLOW FOR
IFR/LIFR FOG DEVELOPMENT OVERNIGHT. FOG AND LOW STATUS HAS ALREADY
DEVELOPED ACROSS NW PA / NE OH AND SOUTHERN ONTARIO THIS EVENING...
AND EXPECT THIS WILL EXPAND NORTH AND EASTWARD ACROSS WESTERN NY
OVERNIGHT AND REMAIN IN PLACE THROUGH SUNDAY MORNING. NEED TO STRESS
THIS IS AN ALL OR NOTHING SITUATION FOR FOG DEVELOPMENT... AND WHILE
WIDESPREAD IFR CIGS/VIS AT OR BELOW AIRFIELD MINIMUMS IS THE MOST
LIKELY OUTCOME... IF THIS FOG DOESNT DEVELOP INTO A TAF SITE IT WILL
LIKELY REMAIN VFR.
ON SUNDAY EXPECT WIDESPREAD IFR IN FOG AND LOW STRATUS TO PERSIST
THROUGH MUCH OF THE MORNING BEFORE SCATTERING OUT TO VFR DURING THE
AFTERNOON. AGAIN...CONDITIONS MAY DROP TO AT OR BELOW AIRFIELD
MINIMUMS FOR A TIME SUNDAY MORNING IF THE FOG BECOMES WIDESPREAD.
OUTLOOK...
MONDAY AND TUESDAY...A CHANCE OF MVFR AND POSSIBLY IFR IN STRATUS.
WEDNESDAY AND THURSDAY...MAINLY VFR.
&&
.MARINE...
A LARGE AREA OF HIGH PRESSURE WILL CONTINUE TO DOMINATE FROM THE
OHIO VALLEY ACROSS THE LOWER LAKES SUNDAY THROUGH THE FIRST HALF OF
NEXT WEEK. THIS WILL PROVIDE A RARE LONG STRETCH OF LIGHT WINDS AND
FLAT WAVE ACTION ON LAKES ERIE AND ONTARIO THROUGH THE MIDDLE OF
NEXT WEEK.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...HITCHCOCK
NEAR TERM...CHURCH/HITCHCOCK
SHORT TERM...SMITH
LONG TERM...SMITH
AVIATION...CHURCH/HITCHCOCK
MARINE...HITCHCOCK
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
928 PM EST SAT DEC 5 2015
.SYNOPSIS...
HIGH PRESSURE WILL PROVIDE DRY...MOSTLY CLEAR...AND RELATIVELY
MILD TEMPERATURES THROUGH THE REMAINDER OF THE WEEKEND AND INTO
NEXT WEEK. HIGH TEMPERATURES WILL BE GENERALLY IN THE 40S WITH
LOWS IN THE 20S AND 30S.
&&
.NEAR TERM /UNTIL 6 PM SUNDAY EVENING/...
AS OF 927 PM EST SATURDAY...MORE TWEAKS TO SKY COVER ACROSS OUR
NORTHERN NY COUNTIES THROUGH THE OVERNIGHT HOURS PER LATEST IR
SATELLITE IMAGERY. 01 UTC RAP LOW LEVEL MOISURE PROGS SHOWING THE
BEST IDEA FOR ITS EVOLUTION AND MOVEMENT OVERNIGHT, BUT THAT`S NOT
SAYING TOO MUCH AS ALL MODELS ARE STRUGGLING TO VARYING DEGREES ON
THIS. IT`S ALSO ANYONE`S GUESS ON ACTUAL TEMPERATURE TRENDS AND
EVENTUAL OVERNIGHT LOWS GIVEN CLOUDY/CLEAR AREAS AND THE FACT THAT
MANY SITES HAVE ALREADY REACHED FORECAST MINIMUM VALUES AS OF 900
PM. SAVING GRACE IS THE FACT THAT SFC DEWPOINT DEPRESSIONS ARE
RATHER SMALL AND WITH THE LACK OF WIND OR ADVECTIVE PROCESSES I
FEEL MOST SITES SHOULD HOLD STEADY OR ONLY SEE READINGS FALL A FEW
MORE DEGREES. WITH THE NARROW TD DEPRESSIONS IN PLACE PATCHY
MIST/FOG STILL A GOOD BET HERE AND THERE, MOST PREVALENT ACROSS
PORTIONS OF EASTERN VERMONT (KCDA ALREADY SHOWING PATCHY BR/FG).
OUTSIDE OF THESE ADJUSTMENTS FORECAST REMAINS IN GOOD SHAPE. HAVE
A GREAT NIGHT.
PRIOR DISCUSSION FROM 247 PM EST SATURDAY...
HEADING INTO SUNDAY...SHOULD SEE ANY RESIDUAL CLOUDS AND/OR
PATCHY FOG DISSIPATE IN THE MORNING WITH MOSTLY SUNNY SKIES.
TEMPERATURES WILL BE QUITE MILD FOR EARLY DECEMBER...WITH HIGHS
47-52F.
&&
.SHORT TERM /6 PM SUNDAY EVENING THROUGH MONDAY NIGHT/...
AS OF 242 PM EST SATURDAY...SURFACE HIGH MOVES OFFSHORE SUNDAY
NIGHT AND UPPER LEVEL RIDGING SLIDES EAST AS WELL. WEAK UPPER LOW
SLIDES SOUTH ACROSS MID-ATLANTIC MONDAY BUT THIS PLACES AREA IN
WEAK TROFINESS WITH A WEAK SURFACE TROF/FRONT SLIDING ACROSS FA
WITH SOME CLOUDS AND A SLIGHT CHANCE OF SHOWER ACROSS THE CANADIAN
BORDER. TEMPS JUST A FEW DEGREES LOWER THAN SUNDAY.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 242 PM EST SATURDAY...A SOMEWHAT CYCLONIC-ZONAL FLOW
THROUGH THIS PERIOD WITH PREDOMINANTLY WESTERLY FLOW BECOMING
CYCLONIC AT TIMES AS SHORTWAVES DROP INTO MEAN FLOW.
WEAK SYSTEMS WITH A CHANCE OF RAIN/SNOW SHOWERS LATE WED NGT INTO
THURSDAY THEN PERHAPS ANOTHER SLIGHT CHANCE OF SHOWERS ON FRIDAY
BEFORE MORE RIDGING POSSIBLE FOR NEXT WEEKEND. THERE ARE SOME TIMING
DIFFERENCE IN MODELS BUT GIVEN THE CUSTOMARY TIMING DIFFERENCES IN A
PATTERN LIKE THIS AND LITTLE PRECIPITATION AS WELL...NOTHING OF ANY
CONSEQUENCE.
THIS FLOW CONTINUES THE ABOVE NORMAL PATTERN ACROSS THE NORTHEAST
WITH HIGH TEMPERATURES NEAR OR JUST ABOVE SEASONABLE TUESDAY WITH
WARMING AS THE WEEK PROGRESSES.
ATTM...NO CLEAR INDICATIONS OF ANY ACCUMULATING SNOWFALL IN THE
VALLEYS (OR EVEN MOUNTAINS) FOR THIS UPCOMING WEEK.
&&
.AVIATION /03Z SUNDAY THROUGH THURSDAY/...
THROUGH 00Z MONDAY...EXPECT MAINLY VFR AT THE CHAMPLAIN VALLEY
AND VERMONT TAF SITES WITH MVFR/IFR AT MSS/SLK. MAY ALSO SEE
PERIOD OF LIGHT FOG OVERNIGHT AT MPV/SLK. LOW CLOUD DECK SLOWLY
ERODING THIS EVENING WITH VFR AT BTV/PBG/RUT/MPV AND NOW MSS.
IFR STRATUS HOLDING STRONG AT SLK AND WILL LIKELY CONTINUE INTO
THE OVERNIGHT HOURS. WITH CLEARING AT MPV AND POSSIBLY SLK AFTER
06Z...A PERIOD OF MVFR FOG/BR IS POSSIBLE. HOWEVER NOT CERTAIN AS
TO DENSITY AND COVERAGE SO HAVE ONLY SHOWN WITH TEMPO 3SM FOR NOW.
LIGHT SOUTH/SOUTHWEST WINDS 10 KNOTS OR LESS THROUGH THE PERIOD.
OUTLOOK 00Z MONDAY THROUGH THURSDAY... 18Z SUNDAY THROUGH 00Z
THURSDAY...MAINLY VFR UNDER HIGH PRESSURE. 00Z THURSDAY
ONWARD...VFR WITH PERIODS OF MVFR POSSIBLE IN LIGHT SHOWERS WITH
WEAK UPPER LEVEL DISTURBANCE.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MUCCILLI
NEAR TERM...JMG/MUCCILLI
SHORT TERM...SLW
LONG TERM...SLW
AVIATION...MV
AREA FORECAST DISCUSSION
NWS BUFFALO NY
732 PM EST SAT DEC 5 2015
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO BRING DRY WEATHER SUNDAY THROUGH
TUESDAY ALTHOUGH LOW CLOUDS WILL LIMIT SUNSHINE AT TIMES. A SERIES
OF WEAK SYSTEMS WILL BRING A CHANCE OF A FEW LIGHT SHOWERS LATER IN
THE WEEK. TEMPERATURES WILL REMAIN WELL ABOVE NORMAL THROUGH THE
NEXT WEEK AND BEYOND.
&&
.NEAR TERM /THROUGH SUNDAY/...
FOG AND LOW STRATUS IS THE PRIMARY FORECAST CONCERN OVERNIGHT INTO
SUNDAY MORNING. A THICK AREA OF STRATUS EAST OF LAKE ONTARIO WILL
LIKELY REMAIN IN PLACE OVERNIGHT... WITH THE REST OF THE FORECAST
AREA AT RISK FOR FOG FORMATION. LOW LEVEL MOISTURE REMAINS IN LOCKED
IN PLACE THIS EVENING UNDER A STRONG SUBSIDENCE INVERSION PER 00Z
BUF SOUNDING AND RECENT AVIAITON SOUNDINGS. THE CLEARING SKIES THIS
EVENING ACROSS WESTERN NY WILL LIKELY PROMOTE ADDITIONAL FOG AND
VERY LOW STRATUS DEVELOPMENT OVERNIGHT AS RADIATIONAL COOLING
QUICKLY RE-SATURATES THE LOW LEVELS.
EXPECT FOG AND STRATUS TO BEGIN TO REFORM BY LATE EVENING AND THEN
EXPAND TO COVER MUCH OF THE AREA BEFORE DAYBREAK SUNDAY. UNLIKE THE
PAST FEW DAYS...FOG MAY BE MORE OF AN ISSUE LATE TONIGHT AND SUNDAY
MORNING. 12Z AND 18Z NAM BUFKIT POINT SOUNDINGS SUGGEST THE
DEVELOPMENT OF A SURFACE BASED INVERSION...AND INITIALLY CLEAR SKIES
EARLY TONIGHT ALSO SUGGEST MORE OF A FOG SCENARIO. FOG WAS
WIDESPREAD AND DENSE THIS MORNING JUST UPSTREAM ACROSS MUCH OF
OHIO...LOWER MICHIGAN...AND INDIANA. A BACKWARDS TRAJECTORY FORECAST
FROM THE HYSPLIT MODEL SHOWS AIR ARRIVING IN BUFFALO AT 12Z SUNDAY
HAS ORIGINS ACROSS EASTERN OHIO AND CENTRAL LAKE ERIE...WHERE DENSE
FOG WAS FOUND THIS MORNING. GIVEN THE UPSTREAM TRENDS AND FORECAST
SOUNDINGS...EXPECT FOG AND STRATUS TO BECOME WIDESPREAD AGAIN LATE
TONIGHT. THE HRRR AND NAM DO NOT COMPETELY AGREE ON HOW THE FOG
DEVELOPMENT WILL EVOLVED... BUT THE GENERAL CONSUS SUPPORTS MUST OF
WESTERN NY SEEING FOG DEVELOP OVERNIGHT. EXPECT THE AREA OF THICK
FOG ACROSS NE OHIO AND NW PA THIS EVENING WILL DEVELOP NORTHWARD
INTO THE SOUTHERN TIER WITH TIME... AND PER 11-3.9 SATELLITE IMAGERY
THIS EXPANSION IS ALREADY UNDERWAY. ALSO THE AREA OF LOW STRATUS /
FOG ACROSS SOUTERN ONTARIO SHOULD START TO EXPAND AND SHIFT EASTWARD
INTO THE NIAGARA FRONTIER OVERNIGHT AS THE SURFACE HIGH SLOWLY
SHIFTS EASTWARD ACROSS THE REGION.
SUNDAY EXPECT FOG AND LOW STRATUS TO HOLD STRONG THROUGH MUCH OF THE
MORNING BENEATH A STRONG SUBSIDENCE INVERSION. THE LOW CLOUDS SHOULD
THEN MIX OUT IN A SIMILAR FASHION TO TODAY WITH INCREASING AMOUNTS
OF SUNSHINE DURING THE AFTERNOON. MODEL GUIDANCE IS NOT HANDLING THE
FOG AND STRATUS POTENTIAL PARTICULARLY WELL. WITH THIS IN
MIND...HAVE FORECAST TEMPERATURES ABOVE GUIDANCE TONIGHT AND BELOW
GUIDANCE ON SUNDAY. THIS WILL TRANSLATE TO LOWS IN THE MID 30S ON
THE LAKE PLAINS AND UPPER 20S TO LOWER 30S ACROSS THE INTERIOR
SOUTHERN TIER AND LEWIS COUNTY. HIGHS ON SUNDAY SHOULD REACH THE
UPPER 40S TO LOWER 50S ACROSS LOWER ELEVATIONS ASSUMING THE FOG AND
STRATUS BURNS OFF BY MIDDAY.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/...
A ZONAL PACIFIC FLOW WILL BE FOUND STRETCHED ACROSS THE CONUS MUCH
OF NEXT WEEK. THIS WILL KEEP GENERALLY FAIR WEATHER IN PLACE WITH
TEMPERATURES RUNNING ON THE MILDER SIDE OF NORMAL FOR EARLY
DECEMBER. SURFACE RIDGING WILL EXTEND SOUTH FROM NORTH OF THE GREAT
LAKES WITH THE ONLY STORM SYSTEM EAST OF THE ROCKIES BEING A MID-
LEVEL CLOSED LOW THAT WILL PASS SOUTH OF OUR FORECAST AREA ACROSS
THE OHIO VALLEY MONDAY THEN OFF THE MID-ATLANTIC COAST ON TUESDAY.
SYNOPTIC LIFT AND MOISTURE WILL BE COLLOCATED WITH THIS LOW CENTER
WITH NO THREAT OF PRECIPITATION FOR OUR FORECAST AREA.
SUNDAY NIGHT...CLEAR TO PARTLY CLOUDY SKIES ACROSS WESTERN AND
CENTRAL NEW YORK WILL ALLOW GOOD RADIATIONAL COOLING AND THE
POTENTIAL FOR PATCHY RIVER VALLEY FOG IN THE SOUTHERN TIER. THIS
COULD MAKE FOR SOME SLICK ROADWAYS IN AREAS WHERE SURFACE TEMPS FALL
BELOW FREEZING. LOWS WILL RANGE FROM THE M30S NEAR THE LAKES TO THE
U20S IN THE SOUTHERN TIER VALLEYS.
MONDAY INTO TUESDAY HAVE LEANED ON THE 05/12Z NAM SHOWING A RETURN
OF LOW CLOUDS UNDER LIGHT NORTHERLY FLOW TRAPPING LAKE MOISTURE
BENEATH A 925MB SUBSIDENCE INVERSION. THE FORECAST CLOUD COVER HAS
THEREFORE BEEN INCREASED TO MOSTLY CLOUDY. THERE MAY ALSO BE A
POTENTIAL FOR SOME PATCHY DRIZZLE BUT CONFIDENCE IS TOO LOW AT THIS
TIME TO INCLUDE IN THE FORECAST.
UNDER A LIGHT NORTHERLY FLOW MONDAY TEMPERATURES WILL RUN CLOSER TO
NORMAL WITH HIGHS TOPPING OUT IN THE LOW 40S FOR MOST. WINDS VEER
AROUND TO THE SOUTH ON TUESDAY AHEAD OF A COLD FRONT/SURFACE TROUGH
CROSSING THE UPPER MIDWEST. TEMPERATURES WILL EDGE UP A LITTLE
WARMER WITH HIGHS RANGING IN THE L/M 40S. OVERNIGHT LOWS WILL
CONTINUE TO RANGE FROM THE M30S NEAR THE LAKES TO U20S WELL INLAND.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
A LOW AMPLITUDE PACIFIC FLOW WILL CONTINUE THROUGH MUCH OF THE REST
OF NEXT WEEK WITH MEDIUM RANGE MODELS THEN INDICATING A POTENTIAL
FOR A MORE AMPLIFIED 500MB PATTERN GOING INTO NEXT WEEKEND WHICH
WOULD BRING WELL ABOVE NORMAL WARMTH.
05/12Z GFS AND ECMWF OPERATIONAL MODELS ALONG WITH GEFS ENSEMBLES
CONTINUE TO SHOW DISAGREEMENT IN THE 500MB PATTERN FOR WEDNESDAY AND
THURSDAY. EACH MODEL/MEMBER IS SHOWING DIFFERENCE IN TIMING AND
LOCATION OF SUBTLE SHORTWAVE TROUGHS MOVING ACROSS THE CONUS. THIS
CONTINUES TO MAKE FOR A LOW CONFIDENCE FORECAST OF ANY MINOR
PRECIPITATION EVENTS AS THESE SHORTWAVES CROSS THE EASTERN GREAT
LAKES. WILL CONTINUE SLIGHT/LOW CHANCE POPS FOR SHOWERS WEDNESDAY
INTO THURSDAY UNTIL CONFIDENCE IN TIMING AND LOCATION INCREASES.
THE PATTERN LOOKS TO AMPLIFY GOING INTO THE WEEKEND WHICH ALSO
LEADS TO A BETTER POTENTIAL FOR MORE SIGNIFICANT WEATHER ALTHOUGH
TIMING BETWEEN THE MODELS REMAINS MISALIGNED. THIS WILL KEEP SLIGHT
CHANCE POPS INTO THE WEEKEND. BETTER CONFIDENCE IS FOUND IN THE
POTENTIAL FOR AN AMPLIFIED RIDGE TO BUILD OVER THE EASTERN STATES
THIS WEEKEND. WHILE PACIFIC FLOW ALOFT AND SOUTHERLY SURFACE WINDS
WILL HELP BOOST TEMPS TOWARD 50 THURSDAY AND FRIDAY...AN AMPLIFIED
500MB RIDGE /IN WHICH NAEFS ENSEMBLES BUILD OVER +2SD/ WOULD MAKE
60S A POSSIBILITY FOR THE WEEKEND.
LOOKING FURTHER OUT INTO THE SECOND FULL WEEK OF DECEMBER...BOTH
THE ECMWF AND GFS BASED ENSEMBLES ARE IN STRONG AGREEMENT THAT THE
PACIFIC BASED FLOW COULD TEMPORARILY BREAK DOWN OVER THE LOWER 48.
A NICE SIZED CHUNK OF -12 TO -16C H85 AIR IS ADVERTISED TO MOVE
FROM THE CANADIAN PRAIRIES INTO THE UPPER MISSISSIPPI VALLEY.
SHOULD THIS AIRMASS MAKE IT TO THE OHIO VALLEY...IT WOULD BE IN A
FAVORABLE POSITION TO EVENTUALLY GENERATE SOME SIGNIFICANT LAKE
SNOWS EAST OF BOTH LAKES ERIE AND ONTARIO. THERE ARE PLENTY OF `IFS`
WITH THIS SCNEARIO THOUGH...BUT IT WILL BE INTERESTING TO KEEP AN
EYE ON AS WE MOVE DEEPER INTO PREPARATIONS FOR THE UPCOMING
HOLIDAY SEASON.
&&
.AVIATION /01Z SUNDAY THROUGH THURSDAY/...
MVFR STRATUS WILL PERSIST EAST OF LAKE ONTARIO TONIGHT AND INTO
SUNDAY...WITH SOME PATCH FOG DEVELOPMENT POSSIBLE LATER TONIGHT.
ACROSS WESTERN NY... CLEAR VFR SKIES THIS EVENING SHOULD ALLOW FOR
IFR/LIFR FOG DEVELOPMENT OVERNIGHT. FOG AND LOW STATUS HAS ALREADY
DEVELOPED ACROSS NW PA / NE OH AND SOUTHERN ONTARIO THIS EVENING...
AND EXPECT THIS WILL EXPAND NORTH AND EASTWARD ACROSS WESTERN NY
OVERNIGHT AND REMAIN IN PLACE THROUGH SUNDAY MORNING. NEED TO STRESS
THIS IS AN ALL OR NOTHING SITUATION FOR FOG DEVELOPMENT... AND WHILE
WIDESPREAD IFR CIGS WITH CONDITIONS POSSIBLY DROPPING TO OR BELOW
AIRFIELD MINIMUMS IS THE MOST LIKELY OUTCOME... IF THIS FOG DOESNT
DEVELOP INTO A TAF SITE IT WILL LIKELY REMAIN VFR.
ON SUNDAY EXPECT WIDESPREAD IFR IN FOG AND LOW STRATUS TO PERSIST
THROUGH MUCH OF THE MORNING BEFORE SCATTERING OUT TO VFR DURING THE
AFTERNOON. AGAIN...CONDITIONS MAY DROP TO AT OR BELOW AIRFIELD
MINIMUMS FOR A TIME SUNDAY MORNING IF THE FOG BECOMES WIDESPREAD.
OUTLOOK...
MONDAY AND TUESDAY...A CHANCE OF MVFR AND POSSIBLY IFR IN STRATUS.
WEDNESDAY AND THURSDAY...MAINLY VFR.
&&
.MARINE...
A LARGE AREA OF HIGH PRESSURE WILL CONTINUE TO DOMINATE FROM THE
OHIO VALLEY ACROSS THE LOWER LAKES SUNDAY THROUGH THE FIRST HALF OF
NEXT WEEK. THIS WILL PROVIDE A RARE LONG STRETCH OF LIGHT WINDS AND
FLAT WAVE ACTION ON LAKES ERIE AND ONTARIO THROUGH THE MIDDLE OF
NEXT WEEK.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...HITCHCOCK
NEAR TERM...CHURCH/HITCHCOCK
SHORT TERM...SMITH
LONG TERM...SMITH/RSH
AVIATION...CHURCH/HITCHCOCK
MARINE...HITCHCOCK
AREA FORECAST DISCUSSION
NWS BUFFALO NY
718 PM EST SAT DEC 5 2015
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO BRING DRY WEATHER SUNDAY THROUGH
TUESDAY ALTHOUGH LOW CLOUDS WILL LIMIT SUNSHINE AT TIMES. A SERIES
OF WEAK SYSTEMS WILL BRING A CHANCE OF A FEW LIGHT SHOWERS LATER IN
THE WEEK. TEMPERATURES WILL REMAIN WELL ABOVE NORMAL THROUGH THE
NEXT WEEK AND BEYOND.
&&
.NEAR TERM /THROUGH SUNDAY/...
FOG AND LOW STRATUS IS THE PRIMARY FORECAST CONCERN OVERNIGHT INTO
SUNDAY MORNING. A THICK AREA OF STRATUS EAST OF LAKE ONTARIO WILL
LIKELY REMAIN IN PLACE OVERNIGHT... WITH THE REST OF THE FORECAST
AREA AT RISK FOR FOG FORMATION. LOW LEVEL MOISTURE REMAINS IN LOCKED
IN PLACE THIS EVENING UNDER A STRONG SUBSIDENCE INVERSION PER 00Z
BUF SOUNDING AND RECENT AVIAITON SOUNDINGS. THE CLEARING SKIES THIS
EVENING ACROSS WESTERN NY WILL LIKELY PROMOTE ADDITIONAL FOG AND
VERY LOW STRATUS DEVELOPMENT OVERNIGHT AS RADIATIONAL COOLING
QUICKLY RE-SATURATES THE LOW LEVELS.
EXPECT FOG AND STRATUS TO BEGIN TO REFORM BY LATE EVENING AND THEN
EXPAND TO COVER MUCH OF THE AREA BEFORE DAYBREAK SUNDAY. UNLIKE THE
PAST FEW DAYS...FOG MAY BE MORE OF AN ISSUE LATE TONIGHT AND SUNDAY
MORNING. 12Z AND 18Z NAM BUFKIT POINT SOUNDINGS SUGGEST THE
DEVELOPMENT OF A SURFACE BASED INVERSION...AND INITIALLY CLEAR SKIES
EARLY TONIGHT ALSO SUGGEST MORE OF A FOG SCENARIO. FOG WAS
WIDESPREAD AND DENSE THIS MORNING JUST UPSTREAM ACROSS MUCH OF
OHIO...LOWER MICHIGAN...AND INDIANA. A BACKWARDS TRAJECTORY FORECAST
FROM THE HYSPLIT MODEL SHOWS AIR ARRIVING IN BUFFALO AT 12Z SUNDAY
HAS ORIGINS ACROSS EASTERN OHIO AND CENTRAL LAKE ERIE...WHERE DENSE
FOG WAS FOUND THIS MORNING. GIVEN THE UPSTREAM TRENDS AND FORECAST
SOUNDINGS...EXPECT FOG AND STRATUS TO BECOME WIDESPREAD AGAIN LATE
TONIGHT. THE HRRR AND NAM DO NOT COMPETELY AGREE ON HOW THE FOG
DEVELOPMENT WILL EVOLVED... BUT THE GENERAL CONSUS SUPPORTS MUST OF
WESTERN NY SEEING FOG DEVELOP OVERNIGHT. EXPECT THE AREA OF THICK
FOG ACROSS NE OHIO AND NW PA THIS EVENING WILL DEVELOP NORTHWARD
INTO THE SOUTHERN TIER WITH TIME... AND PER 11-3.9 SATELLITE IMAGERY
THIS EXPANSION IS ALREADY UNDERWAY. ALSO THE AREA OF LOW STRATUS /
FOG ACROSS SOUTERN ONTARIO SHOULD START TO EXPAND AND SHIFT EASTWARD
INTO THE NIAGARA FRONTIER OVERNIGHT AS THE SURFACE HIGH SLOWLY
SHIFTS EASTWARD ACROSS THE REGION.
SUNDAY EXPECT FOG AND LOW STRATUS TO HOLD STRONG THROUGH MUCH OF THE
MORNING BENEATH A STRONG SUBSIDENCE INVERSION. THE LOW CLOUDS SHOULD
THEN MIX OUT IN A SIMILAR FASHION TO TODAY WITH INCREASING AMOUNTS
OF SUNSHINE DURING THE AFTERNOON. MODEL GUIDANCE IS NOT HANDLING THE
FOG AND STRATUS POTENTIAL PARTICULARLY WELL. WITH THIS IN
MIND...HAVE FORECAST TEMPERATURES ABOVE GUIDANCE TONIGHT AND BELOW
GUIDANCE ON SUNDAY. THIS WILL TRANSLATE TO LOWS IN THE MID 30S ON
THE LAKE PLAINS AND UPPER 20S TO LOWER 30S ACROSS THE INTERIOR
SOUTHERN TIER AND LEWIS COUNTY. HIGHS ON SUNDAY SHOULD REACH THE
UPPER 40S TO LOWER 50S ACROSS LOWER ELEVATIONS ASSUMING THE FOG AND
STRATUS BURNS OFF BY MIDDAY.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/...
A ZONAL PACIFIC FLOW WILL BE FOUND STRETCHED ACROSS THE CONUS MUCH
OF NEXT WEEK. THIS WILL KEEP GENERALLY FAIR WEATHER IN PLACE WITH
TEMPERATURES RUNNING ON THE MILDER SIDE OF NORMAL FOR EARLY
DECEMBER. SURFACE RIDGING WILL EXTEND SOUTH FROM NORTH OF THE GREAT
LAKES WITH THE ONLY STORM SYSTEM EAST OF THE ROCKIES BEING A MID-
LEVEL CLOSED LOW THAT WILL PASS SOUTH OF OUR FORECAST AREA ACROSS
THE OHIO VALLEY MONDAY THEN OFF THE MID-ATLANTIC COAST ON TUESDAY.
SYNOPTIC LIFT AND MOISTURE WILL BE COLLOCATED WITH THIS LOW CENTER
WITH NO THREAT OF PRECIPITATION FOR OUR FORECAST AREA.
SUNDAY NIGHT...CLEAR TO PARTLY CLOUDY SKIES ACROSS WESTERN AND
CENTRAL NEW YORK WILL ALLOW GOOD RADIATIONAL COOLING AND THE
POTENTIAL FOR PATCHY RIVER VALLEY FOG IN THE SOUTHERN TIER. THIS
COULD MAKE FOR SOME SLICK ROADWAYS IN AREAS WHERE SURFACE TEMPS FALL
BELOW FREEZING. LOWS WILL RANGE FROM THE M30S NEAR THE LAKES TO THE
U20S IN THE SOUTHERN TIER VALLEYS.
MONDAY INTO TUESDAY HAVE LEANED ON THE 05/12Z NAM SHOWING A RETURN
OF LOW CLOUDS UNDER LIGHT NORTHERLY FLOW TRAPPING LAKE MOISTURE
BENEATH A 925MB SUBSIDENCE INVERSION. THE FORECAST CLOUD COVER HAS
THEREFORE BEEN INCREASED TO MOSTLY CLOUDY. THERE MAY ALSO BE A
POTENTIAL FOR SOME PATCHY DRIZZLE BUT CONFIDENCE IS TOO LOW AT THIS
TIME TO INCLUDE IN THE FORECAST.
UNDER A LIGHT NORTHERLY FLOW MONDAY TEMPERATURES WILL RUN CLOSER TO
NORMAL WITH HIGHS TOPPING OUT IN THE LOW 40S FOR MOST. WINDS VEER
AROUND TO THE SOUTH ON TUESDAY AHEAD OF A COLD FRONT/SURFACE TROUGH
CROSSING THE UPPER MIDWEST. TEMPERATURES WILL EDGE UP A LITTLE
WARMER WITH HIGHS RANGING IN THE L/M 40S. OVERNIGHT LOWS WILL
CONTINUE TO RANGE FROM THE M30S NEAR THE LAKES TO U20S WELL INLAND.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
A LOW AMPLITUDE PACIFIC FLOW WILL CONTINUE THROUGH MUCH OF THE REST
OF NEXT WEEK WITH MEDIUM RANGE MODELS THEN INDICATING A POTENTIAL
FOR A MORE AMPLIFIED 500MB PATTERN GOING INTO NEXT WEEKEND WHICH
WOULD BRING WELL ABOVE NORMAL WARMTH.
05/12Z GFS AND ECMWF OPERATIONAL MODELS ALONG WITH GEFS ENSEMBLES
CONTINUE TO SHOW DISAGREEMENT IN THE 500MB PATTERN FOR WEDNESDAY AND
THURSDAY. EACH MODEL/MEMBER IS SHOWING DIFFERENCE IN TIMING AND
LOCATION OF SUBTLE SHORTWAVE TROUGHS MOVING ACROSS THE CONUS. THIS
CONTINUES TO MAKE FOR A LOW CONFIDENCE FORECAST OF ANY MINOR
PRECIPITATION EVENTS AS THESE SHORTWAVES CROSS THE EASTERN GREAT
LAKES. WILL CONTINUE SLIGHT/LOW CHANCE POPS FOR SHOWERS WEDNESDAY
INTO THURSDAY UNTIL CONFIDENCE IN TIMING AND LOCATION INCREASES.
THE PATTERN LOOKS TO AMPLIFY GOING INTO THE WEEKEND WHICH ALSO
LEADS TO A BETTER POTENTIAL FOR MORE SIGNIFICANT WEATHER ALTHOUGH
TIMING BETWEEN THE MODELS REMAINS MISALIGNED. THIS WILL KEEP SLIGHT
CHANCE POPS INTO THE WEEKEND. BETTER CONFIDENCE IS FOUND IN THE
POTENTIAL FOR AN AMPLIFIED RIDGE TO BUILD OVER THE EASTERN STATES
THIS WEEKEND. WHILE PACIFIC FLOW ALOFT AND SOUTHERLY SURFACE WINDS
WILL HELP BOOST TEMPS TOWARD 50 THURSDAY AND FRIDAY...AN AMPLIFIED
500MB RIDGE /IN WHICH NAEFS ENSEMBLES BUILD OVER +2SD/ WOULD MAKE
60S A POSSIBILITY FOR THE WEEKEND.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
MVFR STRATUS WILL PERSIST EAST OF LAKE ONTARIO TONIGHT AND INTO
SUNDAY... WITH SOME PATCH FOG DEVELOPMENT POSSIBLE LATER TONIGHT.
ACROSS WESTERN NY... CLEAR VFR SKIES THIS EVENING SHOULD ALLOW FOR
IFR/LIFR FOG DEVELOPMENT OVERNIGHT. FOG AND LOW STATUS HAS ALREADY
DEVELOPED ACROSS NW PA / NE OH AND SOUTHERN ONTARIO THIS EVENING...
AND EXPECT THIS WILL EXPAND NORTH AND EASTWARD ACROSS WESTERN NY
OVERNIGHT AND REMAIN IN PLACE THROUGH SUNDAY MORNING. NEED TO STRESS
THIS IS AN ALL OR NOTHING SITUATION FOR FOG DEVELOPMENT... AND WHILE
WIDESPREAD IFR CIGS WITH CONDITIONS POSSIBLY DROPPING TO OR BELOW
AIRFIELD MINIMUMS IS THE MOST LIKELY OUTCOME... IF THIS FOG DOESNT
DEVELOP INTO A TAF SITE IT WILL LIKELY REMAIN VFR.
ON SUNDAY EXPECT WIDESPREAD IFR IN FOG AND LOW STRATUS TO PERSIST
THROUGH MUCH OF THE MORNING BEFORE SCATTERING OUT TO VFR DURING THE
AFTERNOON. AGAIN...CONDITIONS MAY DROP TO AT OR BELOW AIRFIELD
MINIMUMS FOR A TIME SUNDAY MORNING IF THE FOG BECOMES WIDESPREAD.
OUTLOOK...
MONDAY AND TUESDAY...A CHANCE OF MVFR AND POSSIBLY IFR IN STRATUS.
WEDNESDAY AND THURSDAY...MAINLY VFR.
&&
.MARINE...
A LARGE AREA OF HIGH PRESSURE WILL CONTINUE TO DOMINATE FROM THE
OHIO VALLEY ACROSS THE LOWER LAKES SUNDAY THROUGH THE FIRST HALF OF
NEXT WEEK. THIS WILL PROVIDE A RARE LONG STRETCH OF LIGHT WINDS AND
FLAT WAVE ACTION ON LAKES ERIE AND ONTARIO THROUGH THE MIDDLE OF
NEXT WEEK.
&&
.CLIMATE...
TEMPERATURES ACROSS WESTERN AND NORTH CENTRAL NEW YORK HAVE AVERAGED
WELL ABOVE NORMAL SINCE HALLOWEEN...LARGELY DUE TO A POWERFUL EL
NINO EVENT THAT IS IN PLACE OVER THE EQUATORIAL PACIFIC. THE
STRENGTH OF THE CURRENT EL NINO IS SIMILAR TO THE HISTORIC ONE FROM
1997-98 WHEN OUR REGION BASKED IN ONE OF THE MILDEST WINTERS OF THE
PAST SIXTY YEARS.
THE MILDER WEATHER DID HAVE AN IMPACT ON LAKE SNOWS THAT SEASON.
SNOWFALL FOR THAT PARTICULAR WINTER AVERAGED WELL BELOW NORMAL...
WITH LAKE EFFECT AREAS ONLY RECEIVING ABOUT HALF AS MUCH SNOW AS
USUAL. THE LACK OF SNOWFALL WAS NOT AS PERCEPTIBLE IN NON-LAKE
EFFECT AREAS THOUGH AS A FAVORABLE SYNOPTIC STORM TRACK ALLOWED FOR
NEAR NORMAL AMOUNTS...WITH THE FINGER LAKES REGION ACTUALLY
EXPERIENCING MORE SNOW THAN NORMAL.
DURING THE PAST SIX WEEKS...THERE HAVE BEEN TWO NOTICEABLE
HEMISPHERIC PATTERNS THAT HAVE SUPPORTED THE MILD WEATHER. THE
FIRST IS DIRECTLY RELATED TO STRONG EL NINOS...THAT BEING AN
ANOMALOUSLY STRONG ASIAN/NORTH PACIFIC JET. NOT ONLY IS THIS JET
STRONGER NORMAL BUT IS APPEARS TO BE DISPLACED SEVERAL HUNDRED
MILES FURTHER NORTH. THE EFFECTS OF THIS ARE TWO FOLD. IT
SUPPRESSES THE DEVELOPMENT OF A WEST COAST RIDGE...WHICH WAS
DOMINANT THE PAST TWO WINTERS...AND IT ALSO HELPS TO FLOOD THE
BULK OF NORTH AMERICA WITH PACIFIC MODIFIED AIR. WHILE KEEPING
PACIFIC BASED AIR IN PLACE...THIS PATTERN ALSO BLOCKS ANY ATTEMPT
AT ANY REAL COLD AIR FROM MAKING ITS WAY SOUTH. TRUE COLD AIR UP
TO THIS POINT HAS BEEN LOCKED IN PLACE BETWEEN THE CANADIAN
ARCHIPELAGO AND SIBERIA...OR POLEWARD OF 60N.
THE OTHER KEY HEMISPHERIC FEATURE HAS BEEN THE PERSISTENCE OF AN
ICELANDIC LOW. THIS PATTERN ENHANCES THE MID AND UPPER LEVEL JET AS
IT EXITS NORTH AMERICA...THUS KEEPING A STRONG LOW AMPLITUDE FLOW
ACROSS THE NORTH ATLANTIC. WITHOUT ANY HIGH LATITUDE BLOCKING (EX
GREENLAND BLOCK)...THE STRONG WEST TO EAST JET CAN REMAIN DOMINANT.
THE RESULT IS PERSISTENT `MILD` WEATHER ACROSS THE EASTERN HALF OF
NORTH AMERICA AS WELL AS EUROPE (POSITIVE NAO TRAIT).
MEDIUM AND LONG RANGE GUIDANCE CONTINUES TO KEEP THIS GENERAL
PATTERN IN PLACE FOR THE FORESEEABLE FUTURE...SO A CHANGE TO THE
GENERAL MILD PATTERN IS NOT ANTICIPATED THROUGH AT LEAST MID MONTH.
ANY COLD AIR THAT IS NEEDED FOR SIGNIFICANT LAKE EFFECT WOULD HAVE
TO BE `MANUFACTURED` LOCALLY...WHICH IS NOT SOMETHING THAT IS
TYPICALLY EXPERIENCED FOR MESOSCALE EVENTS SUCH AS LAKE EFFECT.
SUCH A PROCESS IS MORE FAVORABLE FOR LARGER SYNOPTIC SYSTEMS.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...HITCHCOCK
NEAR TERM...CHURCH/HITCHCOCK
SHORT TERM...SMITH
LONG TERM...SMITH
AVIATION...CHURCH/HITCHCOCK
MARINE...HITCHCOCK
CLIMATE...RSH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1250 PM EST FRI DEC 4 2015
.SYNOPSIS...HIGH PRESSURE WILL REMAIN OVER THE REGION THROUGH THE
WEEKEND. LOW PRESSURE MOVES NORTH OFF OF THE CAROLINA COAST EARLY
NEXT WEEK.
&&
.NEAR TERM /THROUGH SATURDAY/...
AS OF 945 AM FRIDAY...
WATER VAPOR SHOWED VERY DRY MID-LEVEL AIR OVER CENTRAL NORTH
CAROLINA...AND RAP SOUNDINGS SHOW DRY AIR CONTINUING THROUGH THE
COLUMN THROUGH TODAY...AND INTO TONIGHT. ALTHOUGH THERE IS A
WEAKNESS IN HEIGHTS ALOFT AND A MODEST SHEAR AXIS IN PLACE AS ALSO
NOTED ON WATER VAPOR AND ON THE FORECAST GUIDANCE...K INDICES ARE
VERY NEGATIVE AND SUBSIDENCE PREVAILS. CIRRUS WAS FINALLY MOVING OFF
TO THE EAST AS THE UPPER- AND MID-LEVEL JETS MOVE EAST...WHICH BY
THE MID AFTERNOON SHOULD BE AT OR JUST OFF OF THE NORTH CAROLINA
COAST. A FEW GUSTS WITH MIXING IN THE TEENS KNOTS...TO EARLY
AFTERNOON...SHOULD GRADUALLY SUBSIDE WITH LIGHT WINDS THROUGHOUT
CENTRAL NORTH CAROLINA BY EVENING. HIGHEST GUSTS IN A RELATIVE SENSE
SHOULD BE TOWARD KFAY...KCTZ... KGSB...AND KRWI WHERE THE SURFACE
GRADIENT IS JUST SLIGHTLY TIGHTER AND 925MB WINDS ARE
STRONGER...THOUGH THESE SUBSIDE TO LESS THAN 10KT THIS AFTERNOON.
TEMPERATURES HAVE RISEN QUICKLY WITH SUN EARLY THIS MORNING AND
OPTED TO RAISE MAXES IN MOST LOCATIONS BUT JUST A DEGREE OR
TWO...CLOSER TO THE MAV MOS GUIDANCE AND IN CONJUNCTION WITH VALUES
NOTED BY 1000-850MB THICKNESSES.
DRY AND SEASONABLY COOL CONDITIONS CONTINUE THROUGH SATURDAY. MIN
TEMPS TONIGHT WILL MAINLY BE NEAR OR SLIGHTLY BELOW FREEZING THOUGH
THE NORMALLY COLDER LOCATIONS WILL BE IN THE UPPER 20S. HIGH
TEMPERATURES SATURDAY WILL AVERAGE A DEGREE OR TWO WARMER...MID
TO UPPER 50S.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/...
AS OF 320 AM FRIDAY...
HIGH PRESSURE AT THE SURFACE AND ALOFT WILL REMAIN OVERHEAD SATURDAY
NIGHT THROUGH SUNDAY THEN DRIFT EAST AND WEAKEN SUNDAY NIGHT. THE
LOW LEVEL AIR MASS WILL CONTINUE TO MODIFY...SUPPORTING HIGH TEMPS
SUNDAY WELL INTO THE 50S TO AROUND 60. STILL CHILLY SATURDAY NIGHT
WITH MIN TEMPS NEAR FREEZING...UPPER 20S AT THE NORMALLY COLDER
LOCATIONS. INCREASING MOISTURE THROUGH THE COLUMN WILL RESULT IN
"WARMER" OVERNIGHT TEMPS IN THE 30S TO AROUND 40. BASED ON MODEL
TRENDS OF A SLOWER ARRIVAL OF DEEPER MOISTURE AND ENOUGH LIFT TO
GENERATE LIGHT PRECIP...HAVE REMOVED THE MENTION OF SLIGHT CHANCE
POPS FROM THE FORECAST FOR SUNDAY NIGHT.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 225 AM FRIDAY...
MONDAY THROUGH TUESDAY: MEDIUM RANGE MODELS CONTINUE TO STRUGGLE
WITH THE TRACK AND TIMING OF A MID LEVEL LOW EXPECTED TO SHIFT
EASTWARD FROM THE TN/OH VALLEY REGION MONDAY MORNING TO OFF THE MID
ATLANTIC COAST BY AT LEAST TUESDAY EVENING. BOTH THE ECMWF AND GFS
HAVE TRENDED NORTHWARD WITH THE TRACK OF THE MID LEVEL LOW THOUGH...
AND FURTHER OFFSHORE WITH A DEVELOPING COASTAL LOW DURING THIS TIME
FRAME. THIS WOULD RESULT IN LESS OF A CHANCE OF RAIN ON MONDAY INTO
TUESDAY FOR CENTRAL NC. HOWEVER... GIVEN THE DRAMATIC SHIFT IN THE
OPERATIONAL RUNS OF THE GFS AND ECMWF OVER THE LAST 24 HOURS WILL
CONTINUE TO HOLD ONTO SOME LOW END CHANCE POPS FOR MONDAY INTO
MONDAY NIGHT... WITH THE BEST CHANCE ACROSS THE SOUTHEAST/EASTERN
PORTIONS OF CENTRAL NC (GENERALLY EAST OF RALEIGH). GIVEN THIS TREND
IN THE MODELS WILL RAISE HIGH TEMPS SOME FOR MONDAY AND KEEP HIGHS
SIMILAR FOR TUESDAY. THIS YIELDS HIGHS IN THE MID TO UPPER 50S...
WITH EVEN A FEW LOCATIONS POSSIBLY TOUCHING 60. LOW TEMPS TUESDAY
MORNING ARE EXPECTED TO RANGE FROM THE MID 30S NW TO THE LOWER TO
MID 40S SE (DEPENDING ON THE AMOUNT OF CLOUD COVER AND POSSIBLE
PRECIP). OVERALL... HAVE TREND THE FORECAST MORE TO THE LAST TWO
RUNS OF THE ECMWF... GIVEN BETTER RUN TO RUN CONTINUITY.
TUESDAY NIGHT THROUGH THURSDAY: AFTER A BRIEF PERIOD OF MID LEVEL
S/W RIDGING... MEDIUM RANGE MODELS STRUGGLE WITH A FAIRLY
PROGRESSIVE PATTERN OF FAST MOVING MID LEVEL DISTURBANCES IN A
GENERAL MEAN L/W BROAD TROUGH ACROSS THE EASTERN HALF OF THE
COUNTRY. GIVEN THESE HARD TO TIME DISTURBANCES EXPECTED TO MOVE
ACROSS THE REGION DURING THIS TIME FRAME... WILL KEEP TEMPS NEAR
NORMAL AS LOW LEVEL THICKNESS VALUES ARE PROGGED TO REMAIN NEAR
NORMAL. THIS YIELDS HIGHS IN THE MID TO UPPER 50S GENERALLY... WITH
LOWS IN THE 30S TO NEAR 40 SE... AND DRY CONDITIONS FOR NOW.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
AS OF 1250 PM FRIDAY...
VFR CONDITIONS PERSIST THROUGH...AND BEYOND...THE 18Z VALID TAF
PERIOD. NORTH-TO-NORTHEAST SURFACE WINDS DIMINISH SOME THIS EVENING.
MODEST GUSTINESS...IN THE TEENS KNOTS AND RELATIVELY A LITTLE HIGHER
TOWARD KFAY AND KRWI...WITH MIXING OCCURS AGAIN SATURDAY MORNING.
THE NAM GUIDANCE SUGGESTS THE POTENTIAL FOR VERY LOW-LEVEL MOISTURE
MOVING INTO CENTRAL NORTH CAROLINA TOWARD INTERSTATE 95 ON THE
NORTHEAST FLOW EARLY SUNDAY MORNING. THE GFS IS DRIER...AND
CURRENTLY IT WOULD SEEM THE HIGHER PROBABILITY OF ANY LOW CLOUDS
WILL REMAIN CLOSER TO THE COAST WHERE THE AXIS OF HIGHER MOISTURE
SHOULD BE ON THE CONSENSUS OF BOTH NAM AND GFS MOISTURE FIELDS BELOW
1000MB. THERE IS A CHANCE OF SUB-VFR CONDITIONS IN CENTRAL NORTH
CAROLINA OVERNIGHT SUNDAY AND MONDAY...WITH THE HIGHER CHANCES AGAIN
TOWARD KFAY AND KRWI RELATIVE TO THE REST OF CENTRAL NORTH CAROLINA.
GOOD PROBABILITIES OF VFR CONDITIONS FOLLOW FOR TUESDAY AND
WEDNESDAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DJF
NEAR TERM...WSS/DJF
SHORT TERM...WSS
LONG TERM...BSD
AVIATION...DJF
AREA FORECAST DISCUSSION
NWS RALEIGH NC
947 AM EST FRI DEC 4 2015
.SYNOPSIS...HIGH PRESSURE WILL BUILD INTO CENTRAL NC TODAY...THEN
LINGER OVERHEAD THROUGH THE WEEKEND.
&&
.NEAR TERM /THROUGH SATURDAY/...
AS OF 945 AM FRIDAY...
WATER VAPOR SHOWED VERY DRY MID-LEVEL AIR OVER CENTRAL NORTH
CAROLINA...AND RAP SOUNDINGS SHOW DRY AIR CONTINUING THROUGH THE
COLUMN THROUGH TODAY...AND INTO TONIGHT. ALTHOUGH THERE IS A
WEAKNESS IN HEIGHTS ALOFT AND A MODEST SHEAR AXIS IN PLACE AS ALSO
NOTED ON WATER VAPOR AND ON THE FORECAST GUIDANCE...K INDICES ARE
VERY NEGATIVE AND SUBSIDENCE PREVAILS. CIRRUS WAS FINALLY MOVING OFF
TO THE EAST AS THE UPPER- AND MID-LEVEL JETS MOVE EAST...WHICH BY
THE MID AFTERNOON SHOULD BE AT OR JUST OFF OF THE NORTH CAROLINA
COAST. A FEW GUSTS WITH MIXING IN THE TEENS KNOTS...TO EARLY
AFTERNOON...SHOULD GRADUALLY SUBSIDE WITH LIGHT WINDS THROUGHOUT
CENTRAL NORTH CAROLINA BY EVENING. HIGHEST GUSTS IN A RELATIVE SENSE
SHOULD BE TOWARD KFAY...KCTZ... KGSB...AND KRWI WHERE THE SURFACE
GRADIENT IS JUST SLIGHTLY TIGHTER AND 925MB WINDS ARE
STRONGER...THOUGH THESE SUBSIDE TO LESS THAN 10KT THIS AFTERNOON.
TEMPERATURES HAVE RISEN QUICKLY WITH SUN EARLY THIS MORNING AND
OPTED TO RAISE MAXES IN MOST LOCATIONS BUT JUST A DEGREE OR
TWO...CLOSER TO THE MAV MOS GUIDANCE AND IN CONJUNCTION WITH VALUES
NOTED BY 1000-850MB THICKNESSES.
DRY AND SEASONABLY COOL CONDITIONS CONTINUE THROUGH SATURDAY. MIN
TEMPS TONIGHT WILL MAINLY BE NEAR OR SLIGHTLY BELOW FREEZING THOUGH
THE NORMALLY COLDER LOCATIONS WILL BE IN THE UPPER 20S. HIGH
TEMPERATURES SATURDAY WILL AVERAGE A DEGREE OR TWO WARMER...MID
TO UPPER 50S.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/...
AS OF 320 AM FRIDAY...
HIGH PRESSURE AT THE SURFACE AND ALOFT WILL REMAIN OVERHEAD SATURDAY
NIGHT THROUGH SUNDAY THEN DRIFT EAST AND WEAKEN SUNDAY NIGHT. THE
LOW LEVEL AIR MASS WILL CONTINUE TO MODIFY...SUPPORTING HIGH TEMPS
SUNDAY WELL INTO THE 50S TO AROUND 60. STILL CHILLY SATURDAY NIGHT
WITH MIN TEMPS NEAR FREEZING...UPPER 20S AT THE NORMALLY COLDER
LOCATIONS. INCREASING MOISTURE THROUGH THE COLUMN WILL RESULT IN
"WARMER" OVERNIGHT TEMPS IN THE 30S TO AROUND 40. BASED ON MODEL
TRENDS OF A SLOWER ARRIVAL OF DEEPER MOISTURE AND ENOUGH LIFT TO
GENERATE LIGHT PRECIP...HAVE REMOVED THE MENTION OF SLIGHT CHANCE
POPS FROM THE FORECAST FOR SUNDAY NIGHT.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 225 AM FRIDAY...
MONDAY THROUGH TUESDAY: MEDIUM RANGE MODELS CONTINUE TO STRUGGLE
WITH THE TRACK AND TIMING OF A MID LEVEL LOW EXPECTED TO SHIFT
EASTWARD FROM THE TN/OH VALLEY REGION MONDAY MORNING TO OFF THE MID
ATLANTIC COAST BY AT LEAST TUESDAY EVENING. BOTH THE ECMWF AND GFS
HAVE TRENDED NORTHWARD WITH THE TRACK OF THE MID LEVEL LOW THOUGH...
AND FURTHER OFFSHORE WITH A DEVELOPING COASTAL LOW DURING THIS TIME
FRAME. THIS WOULD RESULT IN LESS OF A CHANCE OF RAIN ON MONDAY INTO
TUESDAY FOR CENTRAL NC. HOWEVER... GIVEN THE DRAMATIC SHIFT IN THE
OPERATIONAL RUNS OF THE GFS AND ECMWF OVER THE LAST 24 HOURS WILL
CONTINUE TO HOLD ONTO SOME LOW END CHANCE POPS FOR MONDAY INTO
MONDAY NIGHT... WITH THE BEST CHANCE ACROSS THE SOUTHEAST/EASTERN
PORTIONS OF CENTRAL NC (GENERALLY EAST OF RALEIGH). GIVEN THIS TREND
IN THE MODELS WILL RAISE HIGH TEMPS SOME FOR MONDAY AND KEEP HIGHS
SIMILAR FOR TUESDAY. THIS YIELDS HIGHS IN THE MID TO UPPER 50S...
WITH EVEN A FEW LOCATIONS POSSIBLY TOUCHING 60. LOW TEMPS TUESDAY
MORNING ARE EXPECTED TO RANGE FROM THE MID 30S NW TO THE LOWER TO
MID 40S SE (DEPENDING ON THE AMOUNT OF CLOUD COVER AND POSSIBLE
PRECIP). OVERALL... HAVE TREND THE FORECAST MORE TO THE LAST TWO
RUNS OF THE ECMWF... GIVEN BETTER RUN TO RUN CONTINUITY.
TUESDAY NIGHT THROUGH THURSDAY: AFTER A BRIEF PERIOD OF MID LEVEL
S/W RIDGING... MEDIUM RANGE MODELS STRUGGLE WITH A FAIRLY
PROGRESSIVE PATTERN OF FAST MOVING MID LEVEL DISTURBANCES IN A
GENERAL MEAN L/W BROAD TROUGH ACROSS THE EASTERN HALF OF THE
COUNTRY. GIVEN THESE HARD TO TIME DISTURBANCES EXPECTED TO MOVE
ACROSS THE REGION DURING THIS TIME FRAME... WILL KEEP TEMPS NEAR
NORMAL AS LOW LEVEL THICKNESS VALUES ARE PROGGED TO REMAIN NEAR
NORMAL. THIS YIELDS HIGHS IN THE MID TO UPPER 50S GENERALLY... WITH
LOWS IN THE 30S TO NEAR 40 SE... AND DRY CONDITIONS FOR NOW.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
AS OF 635 AM FRIDAY...
THERE IS HIGH CONFIDENCE THAT VFR CONDITIONS WILL EXISTS ACROSS
CENTRAL NC THROUGH SUNDAY. HIGH PRESSURE WILL BUILD INTO THE REGION
TODAY...AND SETTLE OVERHEAD THROUGH THE WEEKEND. SFC WINDS LATER
TODAY WILL BE NORTH-NORTHEAST BETWEEN 07-12KTS...BECOMING LIGHT AND
VARIABLE THIS EVENING.
FORECAST CONFIDENCE LOWERS EARLY NEXT WEEK AS THE MODELS HAVE BEEN
INCONSISTENT IN ITS HANDLING OF AN AREA OF LOW PRESSURE APPROACHING
OUR REGION. STILL...THERE IS POTENTIAL FOR A BRIEF PERIOD OF SUB VFR
CEILINGS MONDAY INTO EARLY TUESDAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MLM
NEAR TERM...WSS/DJF
SHORT TERM...WSS
LONG TERM...BSD
AVIATION...WSS
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
954 PM CST SAT DEC 5 2015
.UPDATE...
ISSUED AT 952 PM CST SAT DEC 5 2015
THE WESTERN EDGE OF THE HIGHER CLOUDS CLEARED EAST OF THE FCST
AREA. IN THEIR WAKE AS THEY DID SOME LOWER CLOUDS AND PATCHY FOG
FORMED FROM FERGUS FALLS TO FOSSTON AND THEN EAST. HRRR AND OTHER
SHORT RANGE MODELS CONTINUE TO HIGHLIGHT THIS AREA AS BEST THREAT
FOR FOG AND DID GO AREAS IN THIS REGION. OTHERWISE SKIES CLEAR.
TEMPS APPEAR OK AT THIS POINT AFTER A QUICK FALL IN SOME SPOTS
JUST PAST SUNSET.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 300 PM CST SAT DEC 5 2015
THE MAIN CHALLENGE WILL CONTINUE TO BE TEMPS WITH VERY MILD TEMPS
CONTINUING INTO THE MIDDLE OF NEXT WEEK. MODELS ARE IN GOOD
AGREEMENT WITH LARGER SCALE FEATURES...BUT STRUGGLING WITH LOW
LEVEL TEMPS. THE MAV MOS GUIDANCE HAS THE BEST HANDLE ON TEMPS IN
THE NEAR TERM AT LEAST.
FOR TONIGHT...THERE HAS BEEN MELTING OF SNOW IN THE PAST 24
HOURS...AND DEWPOINTS ARE IN THE LOW/MID 30S OVER THE SNOW FIELD
THIS AFTERNOON. EVEN WITH WESTERLY WINDS IN THE 5 TO 10 MPH RANGE
FOR MUCH OF THE NIGHT...THERE SHOULD BE AT LEAST SOME PATCHY FOG
OVER THE SNOW AREAS. MODELS DO NOT INDICATE TOO MUCH
FOG...ALTHOUGH THE LATEST HRRR IS INDICATING SOME LOWER VSBYS OVER
MN SINCE WINDS HERE MAY BE FAIRLY LIGHT. TEMPS WILL BE WELL ABOVE
NORMAL GENERALLY IN THE LOW/MID 20S.
FOR SUNDAY...TEMPERATURES WILL BE VERY SIMILAR TO TODAY AND
PERHAPS A FEW DEGREES WARMER WITH 925MB TEMPS NEAR +10C BY
AFTERNOON. WE WILL CONTINUE TO GO THE WARMEST OVER THE SNOW FREE
AREAS IN NORTHEAST ND.
ON SUNDAY NIGHT...ANOTHER MILD NIGHT WITH SOUTHERLY WINDS AROUND
10 MPH THAT SHOULD PRECLUDE ANY FOG FORMATION.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 300 PM CST SAT DEC 5 2015
ON MONDAY...925MB TEMPS COOL SOME BUT ARE STILL WELL ABOVE 0C.
THERE SHOULD BE WESTERLY SFC WINDS THAT WILL ONCE AGAIN BOOST
TEMPS TO AROUND 40 PERHAPS EVEN MID 40S FOR SOME WITH MINIMAL SNOW
COVER.
FOR MONDAY NIGHT...EXPECT INCREASING CLOUDS AND WINDS REMAINING
A BIT ELEVATED. THIS SHOULD MEAN A VERY MILD NIGHT WITH OVERNIGHT
LOWS AROUND 30.
FOR TUE...A SHORTWAVE WILL SWING THROUGH THE REGION AND BRING A
LOW CHANCE FOR SOME LIGHT RAIN. THERE COULD BE A BRIEF WINDOW
EARLY TUE MORNING FOR SOME FREEZING RAIN...BUT WITH TEMPS SO MILD
NOT EXPECTING THIS TO BE ANY TYPE OF THREAT SO WILL KEEP IT ALL
LIQUID RAIN FOR NOW. TEMPS SHOULD ONCE AGAIN WARM TO AROUND 40 OR
THE MID 40S FOR ALL AREAS WITH MORE CLOUDS IN THE EAST.
FORECAST STARTING ON WEDNESDAY NIGHT LOOKS A BIT ON THE ACTIVE
SIDE...POTENTIALLY. THE 12Z GFS AND ECMWF BOTH HAVE AN UPPER LOW
BARRELING ALONG THE CANADIAN BORDER EASTWARD ON WEDNESDAY NIGHT. LOW
LEVEL TEMPS ARE ABOVE FREEZING AHEAD OF THIS SYSTEM...THEN DROPPING
BELOW FREEZING. WHICH MEANS RAIN CHANGING TO SNOW POSSIBLY. THE BEST
CHANCE FOR PRECIPITATION WITH THIS SYSTEM WILL BE OVER NORTHWESTERN
MN...WHERE THE ECMWF HAS SIGNIFICANT SNOWFALL FORECASTED. MODELS ARE
TRENDING A LITTLE FURTHER SOUTH AND WETTER WITH THE WED NIGHT/THU
SYSTEM. A SHOT OF COOLER AIR IS THEN COMING FOR THE WEEKEND. THE GFS
HAS A POTENT LOW MOVING NE ACROSS THE REGION FOR SATURDAY...WHILE
THE ECMWF KEEPS IT A BIT FURTHER EAST AND A LITTLE WEAKER. THE ECMWF
HAS TRENDED WESTWARD A BIT WITH THIS ONE...BACK FURTHER WEST INTO
THE RED RIVER VALLEY. SO...A CHANCE FOR PRECIP ON SATURDAY SEEMS
REASONABLE...WITH COOLER TEMPS COMPARED TO THE PREVIOUS WEEK`S
WARMTH.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 704 PM CST SAT DEC 5 2015
MAIN QUESTION IS FOG POTENTIAL LATE NIGHT/EARLY MORNING. BEMIDJI
TAF STANDS THE BEST CHANCE. SHORT RANGE MODELS INDICATE HIGHEST
THREAT OF LOW VSBYS IN FOG PARK RAPIDS-WADENA. LESS CHANCE
ELSEWHERE. OUTSIDE OF BELTRAMI KEPT REST OF THE TAF SITES VFR.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...RIDDLE
SHORT TERM...DK
LONG TERM...DK/KNUTSVIG
AVIATION...RIDDLE
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
708 PM CST SAT DEC 5 2015
.UPDATE...
ISSUED AT 704 PM CST SAT DEC 5 2015
VARIOUS SHORT RANGE MODELS DO STILL INDICATE MAIN FOG CHANCES IN
SOUTHEASTERN FCST AREA MAINLY AREAS SOUTH AND EAST OF A BEMIDJI TO
FERGUS FALLS LINE. WILL KEEP PATCHY FOG AS IS OVER MOST OF THE
AREA AND CAN FINE TUNE COVERAGE IF NEEDED LATER ON THIS EVENING.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 300 PM CST SAT DEC 5 2015
THE MAIN CHALLENGE WILL CONTINUE TO BE TEMPS WITH VERY MILD TEMPS
CONTINUING INTO THE MIDDLE OF NEXT WEEK. MODELS ARE IN GOOD
AGREEMENT WITH LARGER SCALE FEATURES...BUT STRUGGLING WITH LOW
LEVEL TEMPS. THE MAV MOS GUIDANCE HAS THE BEST HANDLE ON TEMPS IN
THE NEAR TERM AT LEAST.
FOR TONIGHT...THERE HAS BEEN MELTING OF SNOW IN THE PAST 24
HOURS...AND DEWPOINTS ARE IN THE LOW/MID 30S OVER THE SNOW FIELD
THIS AFTERNOON. EVEN WITH WESTERLY WINDS IN THE 5 TO 10 MPH RANGE
FOR MUCH OF THE NIGHT...THERE SHOULD BE AT LEAST SOME PATCHY FOG
OVER THE SNOW AREAS. MODELS DO NOT INDICATE TOO MUCH
FOG...ALTHOUGH THE LATEST HRRR IS INDICATING SOME LOWER VSBYS OVER
MN SINCE WINDS HERE MAY BE FAIRLY LIGHT. TEMPS WILL BE WELL ABOVE
NORMAL GENERALLY IN THE LOW/MID 20S.
FOR SUNDAY...TEMPERATURES WILL BE VERY SIMILAR TO TODAY AND
PERHAPS A FEW DEGREES WARMER WITH 925MB TEMPS NEAR +10C BY
AFTERNOON. WE WILL CONTINUE TO GO THE WARMEST OVER THE SNOW FREE
AREAS IN NORTHEAST ND.
ON SUNDAY NIGHT...ANOTHER MILD NIGHT WITH SOUTHERLY WINDS AROUND
10 MPH THAT SHOULD PRECLUDE ANY FOG FORMATION.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 300 PM CST SAT DEC 5 2015
ON MONDAY...925MB TEMPS COOL SOME BUT ARE STILL WELL ABOVE 0C.
THERE SHOULD BE WESTERLY SFC WINDS THAT WILL ONCE AGAIN BOOST
TEMPS TO AROUND 40 PERHAPS EVEN MID 40S FOR SOME WITH MINIMAL SNOW
COVER.
FOR MONDAY NIGHT...EXPECT INCREASING CLOUDS AND WINDS REMAINING
A BIT ELEVATED. THIS SHOULD MEAN A VERY MILD NIGHT WITH OVERNIGHT
LOWS AROUND 30.
FOR TUE...A SHORTWAVE WILL SWING THROUGH THE REGION AND BRING A
LOW CHANCE FOR SOME LIGHT RAIN. THERE COULD BE A BRIEF WINDOW
EARLY TUE MORNING FOR SOME FREEZING RAIN...BUT WITH TEMPS SO MILD
NOT EXPECTING THIS TO BE ANY TYPE OF THREAT SO WILL KEEP IT ALL
LIQUID RAIN FOR NOW. TEMPS SHOULD ONCE AGAIN WARM TO AROUND 40 OR
THE MID 40S FOR ALL AREAS WITH MORE CLOUDS IN THE EAST.
FORECAST STARTING ON WEDNESDAY NIGHT LOOKS A BIT ON THE ACTIVE
SIDE...POTENTIALLY. THE 12Z GFS AND ECMWF BOTH HAVE AN UPPER LOW
BARRELING ALONG THE CANADIAN BORDER EASTWARD ON WEDNESDAY NIGHT. LOW
LEVEL TEMPS ARE ABOVE FREEZING AHEAD OF THIS SYSTEM...THEN DROPPING
BELOW FREEZING. WHICH MEANS RAIN CHANGING TO SNOW POSSIBLY. THE BEST
CHANCE FOR PRECIPITATION WITH THIS SYSTEM WILL BE OVER NORTHWESTERN
MN...WHERE THE ECMWF HAS SIGNIFICANT SNOWFALL FORECASTED. MODELS ARE
TRENDING A LITTLE FURTHER SOUTH AND WETTER WITH THE WED NIGHT/THU
SYSTEM. A SHOT OF COOLER AIR IS THEN COMING FOR THE WEEKEND. THE GFS
HAS A POTENT LOW MOVING NE ACROSS THE REGION FOR SATURDAY...WHILE
THE ECMWF KEEPS IT A BIT FURTHER EAST AND A LITTLE WEAKER. THE ECMWF
HAS TRENDED WESTWARD A BIT WITH THIS ONE...BACK FURTHER WEST INTO
THE RED RIVER VALLEY. SO...A CHANCE FOR PRECIP ON SATURDAY SEEMS
REASONABLE...WITH COOLER TEMPS COMPARED TO THE PREVIOUS WEEK`S
WARMTH.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 704 PM CST SAT DEC 5 2015
MAIN QUESTION IS FOG POTENTIAL LATE NIGHT/EARLY MORNING. BEMIDJI
TAF STANDS THE BEST CHANCE. SHORT RANGE MODELS INDICATE HIGHEST
THREAT OF LOW VSBYS IN FOG PARK RAPIDS-WADENA. LESS CHANCE
ELSEWHERE. OUTSIDE OF BELTRAMI KEPT REST OF THE TAF SITES VFR.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...RIDDLE
SHORT TERM...DK
LONG TERM...DK/KNUTSVIG
AVIATION...RIDDLE
AREA FORECAST DISCUSSION
NWS BISMARCK ND
320 PM CST FRI DEC 4 2015
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 320 PM CST FRI DEC 4 2015
MILD AND QUIET WEATHER WILL CONTINUE THROUGH SATURDAY.
AS OF 21 UTC...IT IS APPARENT THAT THE LOW-LEVEL INVERSION IS ONLY
SLOWLY BEING ERODED IN SOUTHERLY FLOW...AS SURFACE GUSTS ARE BEING
HELD UNDER 30 KT EVEN IN THE JAMES RIVER VALLEY. FORECAST SOUNDING
PROFILES FROM THE RAP AND HRRR CONTINUE TO SUPPORT WINDS AROUND
60 KT WITHIN 2000 FT AGL THROUGH EARLY EVENING IN EAST CENTRAL ND
AND SO WE WILL HAVE TO MONITOR FOR STRONGER GUSTS...BUT THE CHANCE
OF ADVISORY-TYPE GUSTS APPEARS TO BE DWINDLING.
A MODEST COLD FRONT WILL CROSS THE AREA TONIGHT...TURNING WINDS TO
THE WEST...AND COOLING THE AIR MASS A BIT BY SATURDAY WHEN 850-MB
TEMPERATURES ARE EXPECTED TO DROP TO +1 TO +3 C. HOWEVER...GIVEN
THE FAVORABLE LOW-LEVEL WESTERLY FLOW AND CONTINUED EROSION OF THE
SNOW PACK...WE STILL EXPECT HIGHS IN THE 40S F IN MANY PLACES ON
SATURDAY. IT ALSO APPEARS THAT THE NEAR-SURFACE LAYER WILL BE TOO
TURBULENT TO SUPPORT FOG FORMATION TONIGHT IN AREAS THAT HAVE HAD
SNOWMELT DURING THE DAY.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 320 PM CST FRI DEC 4 2015
THE MAIN HIGHLIGHTS IN THE LONG TERM PERIOD ARE ABOVE NORMAL HIGH
TEMPERATURES THROUGH THE PERIOD...WITH HIGHS IN THE 40S AND SOME 50S
ESPECIALLY SUNDAY AND WEDNESDAY. A COOLING TREND INITIATES FRIDAY
AND CONTINUES THROUGH THE UPCOMING WEEKEND. ALTHOUGH COOLER
CONDITIONS EXPECTED FRIDAY...HIGH TEMPERATURES STILL REMAIN ABOVE
NORMAL WITH HIGHS 35F TO 40F. THE OVERALL PATTERN OF A NEAR ZONAL
FLOW CONTINUES WITH QUICK MOVING SHORTWAVES AND ASSOCIATED SURFACE
FEATURES SLIDING ACROSS WESTERN AND CENTRAL NORTH DAKOTA. THE MAIN
DIFFERENCE ON THE 12Z GFS/ECMWF MODELS RUNS TODAY IS A MORE
WIDESPREAD CHANCE OF MOSTLY RAIN SHOWERS ON TUESDAY ACROSS WESTERN
AND CENTRAL NORTH DAKOTA. ALTHOUGH SOME SNOW SHOWERS ARE POSSIBLE
DURING THE EARLY MORNING. ANOTHER FAIRLY WEAK SHORTWAVE IS SLATED
FOR THURSDAY INTO THURSDAY NIGHT....WITH A POTENTIALLY STRONGER
SHORTWAVE FRIDAY INTO THE WEEKEND. HOWEVER IT IS EVIDENT JUST FROM
THE GFS ENSEMBLE HEIGHTS THAT NEXT WEEKENDS SHORTWAVE HAS A LOT OF
UNCERTAINTY...WITH SEVERAL POSSIBLE SOLUTIONS. THE SUPERBLEND
CURRENTLY HAS A SLIGHT CHANCE/CHANCE OF RAIN AND SNOW FRIDAY/FRIDAY
NIGHT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 320 PM CST FRI DEC 4 2015
SOUTHERLY WIND GUSTS OF 20 TO 30 KT ARE EXPECTED IN SOUTH CENTRAL
ND THIS AFTERNOON AND EARLY EVENING. EVEN STRONGER WINDS OF 50 TO
60 KT ARE EXPECTED AROUND 2000 FT AGL...PRODUCING LOW-LEVEL WIND
SHEAR AND SUGGESTIVE OF SOME RISK FOR SURFACE GUSTS OVER 30 KT.
VFR WEATHER IS GENERALLY EXPECTED THROUGH 18 UTC SATURDAY...BUT
THERE IS A LOW PROBABILITY OF MVFR CEILINGS AT BOTH KJMS AND KMOT
TONIGHT AND SATURDAY MORNING.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...CJS
LONG TERM...KS
AVIATION...CJS
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1228 PM CST FRI DEC 4 2015
.UPDATE...
ISSUED AT 1225 PM CST FRI DEC 4 2015
THE MAIN CHANGE WILL BE TO LOWER TEMPS OVER THE SNOW FIELD IN THE
VALLEY WITH TEMPS STRUGGLING IN THE MID/UPPER 20S WHILE LANGDON IS
48. THEREFORE...WILL TAILOR TEMPS TO THE SNOW/NO SNOW AREAS ONCE
AGAIN. IT STILL LOOKS WINDY WITH THE STRONGEST WINDS ALOFT IN THE
VALLEY IN THE 00-06Z TIMEFRAME...AND WE WILL BE VERY CLOSE IF NOT
INTO WIND ADVISORY CRITERIA AND WILL CONTINUE TO MONITOR.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 325 AM CST FRI DEC 4 2015
MAIN FORECAST CHALLENGE WILL BE TEMPERATURES. GOOD AGREEMENT WITH
MODELS ON MAIN DETAILS.
TEMPERATURES WILL BE THE PRIMARY CHALLENGE THROUGH THE PERIOD
BETWEEN AREAS WITH SNOW COVER VS NO SNOW. OVER A 20 DEGREES SPREAD
IN MAXIMUM TEMPERATURES YESTERDAY BASED JUST ON SNOW COVER. THIS
TREND WILL LIKELY CONTINUE AS LONG AS SNOW COVER EXISTS.
FOR TODAY SURFACE PRESSURE GRADIENT INCREASES FOR BREEZY
CONDITIONS HOWEVER WITH VERY SHALLOW MIXED LAYER STRONGER WINDS
ALOFT NOT LIKELY TO MIX DOWN. WARM COLUMN REMAINS IN PLACE SO MILD
TEMPERATURES TO CONTINUE. DIFFERENCE TODAY FROM YESTERDAY WILL BE
SOUTHERLY VS WESTERLY SURFACE WINDS. A SOUTH WIND COMING ACROSS
SNOW FIELD MAY SOMEWHAT LIMIT TEMPERATURE CLIMB ACROSS SNOW FREE
REGION ACROSS THE NORTHERN FA. MODEL GUIDANCE HAS STRUGGLED WITH
TEMPERATURES AS A RESULT OF SNOW COVER. RUC APPEARED MOST
REALISTIC WITH TEMPERATURES SO GENERALLY FOLLOWED ITS FORECAST.
NORTHERN AREAS MAY STAY JUST SHY OF 50 WITH REMAINDER OF FA
HOLDING IN THE 30S TO AROUND 40.
MIXING WILL HOLD TEMPERATURES UP TONIGHT WITH MINIMUMS AT OR ABOVE
AVERAGE HIGHS FOR THIS TIME OF THE YEAR.
BROAD MID LEVEL TROUGH WILL CROSS THE FA THIS WEEKEND. A WEAK COLD
FRONT WILL CROSS THE REGION SATURDAY. COLUMN LACKING MOISTURE SO A
BIT MORE CLOUD COVER AND WSHFT WILL BE THE ONLY AFFECTS WITH
FROPA. COLUMN COOLER SO TEMPERATURES MAY BE MORE UNIFORM ACROSS
THE FA BUT STILL WELL ABOVE AVERAGE.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 325 AM CST FRI DEC 4 2015
MINIMAL WEATHER IMPACTS WILL CONTINUE REMAINDER OF THE WEEKEND.
WELL ABOVE AVERAGE TEMPERATURES WILL CONTINUE TO WORK ON SHRINKING
EXISTING SNOW PACK. APPEARS TO BE ENOUGH MIXING TO LIMIT NIGHT
TIME FOG DEVELOPMENT WITH DAY TIME MELTING BUT WILL NEED TO
MONITOR.
MODELS INITIALIZED WELL AND CONTINUE TO SHOW A GENERAL BROAD RIDGE
ACROSS THE NRN PLAINS. WITH THE UPPER RIDGE REMAINING IN
PLACE...EXPECT TEMPERATURES TO REMAIN ABOVE NORMAL. HOWEVER...TEMPS
WILL DEPEND ON ANY REMAINING SNOW PACK...AND INDICATIONS ARE IT WILL
CONTINUE TO ERODE...AS HIGH TEMPS LOOK TO BE IN THE UPPER 30S TO LOW
40S THRU THE PERIOD. OTHERWISE...A FEW IMPULSES OF ENERGY WILL
PROPAGATE THRU THE FLOW...BUT WITH A GENERALLY DRY COLUMN DO NOT
ANTICIPATE MUCH IN THE WAY OF PCPN.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1225 PM CST FRI DEC 4 2015
VFR CONDS BUT WINDY. SOUTH WINDS WILL INCREASE BY LATE
AFTERNOON AS INVERSION ERODES AND MOST SITES WILL BE BREEZY
THROUGHOUT THE NIGHT. VFR TOMORROW MORNING WITH WINDS TURNING MORE
WESTERLY.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...DK
SHORT TERM...VOELKER
LONG TERM...HOPKINS/VOELKER
AVIATION...DK
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
921 AM CST FRI DEC 4 2015
.UPDATE...
ISSUED AT 920 AM CST FRI DEC 4 2015
THE MAIN CHALLENGE WILL BE TEMPS AND WINDS. WINDS MAY APPROACH
ADVISORY LEVELS LATE THIS AFTERNOON THROUGH ABOUT 6Z IN THE
VALLEY...WHEN 925MB WINDS INCREASE TO ABOUT 60KT. THERE WILL BE A
VERY STEEP INVERSION SO MIXING THESE WINDS WILL BE TOUGH...BUT IF
WE CAN WARM TO AROUND 40 THEN WE SHOULD MIX AT LEAST 45KT OR SO.
THE SNOW FREE AREAS WILL LIKELY HAVE THE STRONGEST WINDS...SO WE
WILL INCREASE WINDS TO NEAR ADVISORY LEVELS AND CONTINUE TO
MONITOR...WITH GUSTS TO AT LEAST 40MPH LATER TODAY/THIS EVENING.
TEMPS LOOK GOOD AND WE WON/T ADJUST THEM MUCH AT ALL WITH PLENTY
OF SUNSHINE AND INCREASING WINDS HELPING MIX SOME WARM AIR DOWN.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 325 AM CST FRI DEC 4 2015
MAIN FORECAST CHALLENGE WILL BE TEMPERATURES. GOOD AGREEMENT WITH
MODELS ON MAIN DETAILS.
TEMPERATURES WILL BE THE PRIMARY CHALLENGE THROUGH THE PERIOD
BETWEEN AREAS WITH SNOW COVER VS NO SNOW. OVER A 20 DEGREES SPREAD
IN MAXIMUM TEMPERATURES YESTERDAY BASED JUST ON SNOW COVER. THIS
TREND WILL LIKELY CONTINUE AS LONG AS SNOW COVER EXISTS.
FOR TODAY SURFACE PRESSURE GRADIENT INCREASES FOR BREEZY
CONDITIONS HOWEVER WITH VERY SHALLOW MIXED LAYER STRONGER WINDS
ALOFT NOT LIKELY TO MIX DOWN. WARM COLUMN REMAINS IN PLACE SO MILD
TEMPERATURES TO CONTINUE. DIFFERENCE TODAY FROM YESTERDAY WILL BE
SOUTHERLY VS WESTERLY SURFACE WINDS. A SOUTH WIND COMING ACROSS
SNOW FIELD MAY SOMEWHAT LIMIT TEMPERATURE CLIMB ACROSS SNOW FREE
REGION ACROSS THE NORTHERN FA. MODEL GUIDANCE HAS STRUGGLED WITH
TEMPERATURES AS A RESULT OF SNOW COVER. RUC APPEARED MOST
REALISTIC WITH TEMPERATURES SO GENERALLY FOLLOWED ITS FORECAST.
NORTHERN AREAS MAY STAY JUST SHY OF 50 WITH REMAINDER OF FA
HOLDING IN THE 30S TO AROUND 40.
MIXING WILL HOLD TEMPERATURES UP TONIGHT WITH MINIMUMS AT OR ABOVE
AVERAGE HIGHS FOR THIS TIME OF THE YEAR.
BROAD MID LEVEL TROUGH WILL CROSS THE FA THIS WEEKEND. A WEAK COLD
FRONT WILL CROSS THE REGION SATURDAY. COLUMN LACKING MOISTURE SO A
BIT MORE CLOUD COVER AND WSHFT WILL BE THE ONLY AFFECTS WITH
FROPA. COLUMN COOLER SO TEMPERATURES MAY BE MORE UNIFORM ACROSS
THE FA BUT STILL WELL ABOVE AVERAGE.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 325 AM CST FRI DEC 4 2015
MINIMAL WEATHER IMPACTS WILL CONTINUE REMAINDER OF THE WEEKEND.
WELL ABOVE AVERAGE TEMPERATURES WILL CONTINUE TO WORK ON SHRINKING
EXISTING SNOW PACK. APPEARS TO BE ENOUGH MIXING TO LIMIT NIGHT
TIME FOG DEVELOPMENT WITH DAY TIME MELTING BUT WILL NEED TO
MONITOR.
MODELS INITIALIZED WELL AND CONTINUE TO SHOW A GENERAL BROAD RIDGE
ACROSS THE NRN PLAINS. WITH THE UPPER RIDGE REMAINING IN
PLACE...EXPECT TEMPERATURES TO REMAIN ABOVE NORMAL. HOWEVER...TEMPS
WILL DEPEND ON ANY REMAINING SNOW PACK...AND INDICATIONS ARE IT WILL
CONTINUE TO ERODE...AS HIGH TEMPS LOOK TO BE IN THE UPPER 30S TO LOW
40S THRU THE PERIOD. OTHERWISE...A FEW IMPULSES OF ENERGY WILL
PROPAGATE THRU THE FLOW...BUT WITH A GENERALLY DRY COLUMN DO NOT
ANTICIPATE MUCH IN THE WAY OF PCPN.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 620 AM CST FRI DEC 4 2015
WILL SEE INCREASING SOUTH WINDS TODAY OTHERWISE VFR CONDITIONS
EXPECTED WITH NO CIGS.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...DK
SHORT TERM...VOELKER
LONG TERM...HOPKINS/VOELKER
AVIATION...VOELKER
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
622 AM CST FRI DEC 4 2015
.UPDATE...
ISSUED AT 620 AM CST FRI DEC 4 2015
NO UPDATE NECESSARY.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 325 AM CST FRI DEC 4 2015
MAIN FORECAST CHALLENGE WILL BE TEMPERATURES. GOOD AGREEMENT WITH
MODELS ON MAIN DETAILS.
TEMPERATURES WILL BE THE PRIMARY CHALLENGE THROUGH THE PERIOD
BETWEEN AREAS WITH SNOW COVER VS NO SNOW. OVER A 20 DEGREES SPREAD
IN MAXIMUM TEMPERATURES YESTERDAY BASED JUST ON SNOW COVER. THIS
TREND WILL LIKELY CONTINUE AS LONG AS SNOW COVER EXISTS.
FOR TODAY SURFACE PRESSURE GRADIENT INCREASES FOR BREEZY
CONDITIONS HOWEVER WITH VERY SHALLOW MIXED LAYER STRONGER WINDS
ALOFT NOT LIKELY TO MIX DOWN. WARM COLUMN REMAINS IN PLACE SO MILD
TEMPERATURES TO CONTINUE. DIFFERENCE TODAY FROM YESTERDAY WILL BE
SOUTHERLY VS WESTERLY SURFACE WINDS. A SOUTH WIND COMING ACROSS
SNOW FIELD MAY SOMEWHAT LIMIT TEMPERATURE CLIMB ACROSS SNOW FREE
REGION ACROSS THE NORTHERN FA. MODEL GUIDANCE HAS STRUGGLED WITH
TEMPERATURES AS A RESULT OF SNOW COVER. RUC APPEARED MOST
REALISTIC WITH TEMPERATURES SO GENERALLY FOLLOWED ITS FORECAST.
NORTHERN AREAS MAY STAY JUST SHY OF 50 WITH REMAINDER OF FA
HOLDING IN THE 30S TO AROUND 40.
MIXING WILL HOLD TEMPERATURES UP TONIGHT WITH MINIMUMS AT OR ABOVE
AVERAGE HIGHS FOR THIS TIME OF THE YEAR.
BROAD MID LEVEL TROUGH WILL CROSS THE FA THIS WEEKEND. A WEAK COLD
FRONT WILL CROSS THE REGION SATURDAY. COLUMN LACKING MOISTURE SO A
BIT MORE CLOUD COVER AND WSHFT WILL BE THE ONLY AFFECTS WITH
FROPA. COLUMN COOLER SO TEMPERATURES MAY BE MORE UNIFORM ACROSS
THE FA BUT STILL WELL ABOVE AVERAGE.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 325 AM CST FRI DEC 4 2015
MINIMAL WEATHER IMPACTS WILL CONTINUE REMAINDER OF THE WEEKEND.
WELL ABOVE AVERAGE TEMPERATURES WILL CONTINUE TO WORK ON SHRINKING
EXISTING SNOW PACK. APPEARS TO BE ENOUGH MIXING TO LIMIT NIGHT
TIME FOG DEVELOPMENT WITH DAY TIME MELTING BUT WILL NEED TO
MONITOR.
MODELS INITIALIZED WELL AND CONTINUE TO SHOW A GENERAL BROAD RIDGE
ACROSS THE NRN PLAINS. WITH THE UPPER RIDGE REMAINING IN
PLACE...EXPECT TEMPERATURES TO REMAIN ABOVE NORMAL. HOWEVER...TEMPS
WILL DEPEND ON ANY REMAINING SNOW PACK...AND INDICATIONS ARE IT WILL
CONTINUE TO ERODE...AS HIGH TEMPS LOOK TO BE IN THE UPPER 30S TO LOW
40S THRU THE PERIOD. OTHERWISE...A FEW IMPULSES OF ENERGY WILL
PROPAGATE THRU THE FLOW...BUT WITH A GENERALLY DRY COLUMN DO NOT
ANTICIPATE MUCH IN THE WAY OF PCPN.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 620 AM CST FRI DEC 4 2015
WILL SEE INCREASING SOUTH WINDS TODAY OTHERWISE VFR CONDITIONS
EXPECTED WITH NO CIGS.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...VOELKER
SHORT TERM...VOELKER
LONG TERM...HOPKINS/VOELKER
AVIATION...VOELKER
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
330 AM CST FRI DEC 4 2015
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 325 AM CST FRI DEC 4 2015
MAIN FORECAST CHALLENGE WILL BE TEMPERATURES. GOOD AGREEMENT WITH
MODELS ON MAIN DETAILS.
TEMPERATURES WILL BE THE PRIMARY CHALLENGE THROUGH THE PERIOD
BETWEEN AREAS WITH SNOW COVER VS NO SNOW. OVER A 20 DEGREES SPREAD
IN MAXIMUM TEMPERATURES YESTERDAY BASED JUST ON SNOW COVER. THIS
TREND WILL LIKELY CONTINUE AS LONG AS SNOW COVER EXISTS.
FOR TODAY SURFACE PRESSURE GRADIENT INCREASES FOR BREEZY
CONDITIONS HOWEVER WITH VERY SHALLOW MIXED LAYER STRONGER WINDS
ALOFT NOT LIKELY TO MIX DOWN. WARM COLUMN REMAINS IN PLACE SO MILD
TEMPERATURES TO CONTINUE. DIFFERENCE TODAY FROM YESTERDAY WILL BE
SOUTHERLY VS WESTERLY SURFACE WINDS. A SOUTH WIND COMING ACROSS
SNOW FIELD MAY SOMEWHAT LIMIT TEMPERATURE CLIMB ACROSS SNOW FREE
REGION ACROSS THE NORTHERN FA. MODEL GUIDANCE HAS STRUGGLED WITH
TEMPERATURES AS A RESULT OF SNOW COVER. RUC APPEARED MOST
REALISTIC WITH TEMPERATURES SO GENERALLY FOLLOWED ITS FORECAST.
NORTHERN AREAS MAY STAY JUST SHY OF 50 WITH REMAINDER OF FA
HOLDING IN THE 30S TO AROUND 40.
MIXING WILL HOLD TEMPERATURES UP TONIGHT WITH MINIMUMS AT OR ABOVE
AVERAGE HIGHS FOR THIS TIME OF THE YEAR.
BROAD MID LEVEL TROUGH WILL CROSS THE FA THIS WEEKEND. A WEAK COLD
FRONT WILL CROSS THE REGION SATURDAY. COLUMN LACKING MOISTURE SO A
BIT MORE CLOUD COVER AND WSHFT WILL BE THE ONLY AFFECTS WITH
FROPA. COLUMN COOLER SO TEMPERATURES MAY BE MORE UNIFORM ACROSS
THE FA BUT STILL WELL ABOVE AVERAGE.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 325 AM CST FRI DEC 4 2015
MINIMAL WEATHER IMPACTS WILL CONTINUE REMAINDER OF THE WEEKEND.
WELL ABOVE AVERAGE TEMPERATURES WILL CONTINUE TO WORK ON SHRINKING
EXISTING SNOW PACK. APPEARS TO BE ENOUGH MIXING TO LIMIT NIGHTTIMEFOG
DEVELOPMENT WITH DAY TIME MELTING BUT WILL NEED TO MONITOR.
MODELS INITIALIZED WELL AND CONTINUE TO SHOW A GENERAL BROAD RIDGE
ACROSS THE NRN PLAINS. WITH THE UPPER RIDGE REMAINING IN
PLACE...EXPECT TEMPERATURES TO REMAIN ABOVE NORMAL. HOWEVER...TEMPS
WILL DEPEND ON ANY REMAINING SNOW PACK...AND INDICATIONS ARE IT WILL
CONTINUE TO ERODE...AS HIGH TEMPS LOOK TO BE IN THE UPPER 30S TO LOW
40S THRU THE PERIOD. OTHERWISE...A FEW IMPULSES OF ENERGY WILL
PROPAGATE THRU THE FLOW...BUT WITH A GENERALLY DRY COLUMN DO NOT
ANTICIPATE MUCH IN THE WAY OF PCPN.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1143 PM CST THU DEC 3 2015
WINDS WILL BE THE MAIN CONCERN THIS PERIOD AS SOUTHERLY WINDS
BECOME GUSTY BY FRIDAY AFTERNOON. CIRRUS POSSIBLE...WITH VFR
CONDITIONS THROUGH THE PERIOD.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
SHORT TERM...VOELKER
LONG TERM...HOPKINS/VOELKER
AVIATION...TG
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
712 PM EST SAT DEC 5 2015
.SYNOPSIS...
SURFACE HIGH PRESSURE WILL EXTEND ACROSS THE REGION THROUGH
SUNDAY...WITH DRY CONDITIONS EXPECTED. A WEAK AREA OF LOW PRESSURE
WILL MOVE THROUGH THE AREA SUNDAY NIGHT INTO MONDAY...PROVIDING A
CHANCE OF RAIN SHOWERS. GRADUALLY WARMING CONDITIONS ARE EXPECTED
THROUGH THE END OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
ALTHOUGH MOST OF THE FORECAST AREA CLEARED OUT OF THE STRATUS/FOG
BY MID-AFTERNOON...A FEW PATCHES REMAINED IN PLACE. ONE PATCH HAS
BEEN CENTERED OVER FAYETTE AND GREENE COUNTIES. ANOTHER IS LOCATED
OVER THE NWS CLE FORECAST AREA...BUT HAS BEGUN MOVING INTO HARDIN
AND UNION COUNTIES. AS THE SUN BEGAN TO SET...VISIBILITIES IN
THESE AREAS QUICKLY DROPPED TO NEAR-ZERO...AND THERE IS EVERY
REASON TO BELIEVE THAT BOTH AREAS WILL CONTINUE TO EXPAND.
THUS...A DENSE FOG ADVISORY HAS BEEN ISSUED...COVERING 15 COUNTIES
(AND LIKELY TO EXPAND LATER THIS EVENING).
THE REST OF THE FORECAST IS UNCHANGED.
PREVIOUS DISCUSSION >
A SIGNIFICANT DENSE FOG EVENT...WITH SOME RIME ICING...OCCURRED
ACROSS THE AREA THIS MORNING. AS INDICATED IN A SOCIAL MEDIA POST
FROM OUR OFFICE EARLIER TODAY...THE LOW- LEVEL INVERSION WAS
EXCEPTIONALLY STRONG...WARMING FROM ABOUT 25F AT THE SURFACE TO
50F AT 2KFT. THIS INVERSION IS MUCH TOO STRONG TO BE TRULY
BROKEN...BUT THERE HAS BEEN JUST ENOUGH MODIFICATION TO THE AIR
MASS TO ALLOW FOR THE STRATUS TO STEADILY DISSIPATE OVER THE PAST
FEW HOURS.
OVERALL...BOUNDARY LAYER MOISTURE HAS CHANGED VERY LITTLE...AND
SURFACE DEWPOINTS HAVE ACTUALLY INCREASED TODAY. THIS CONTRASTS
REMARKABLY WITH RAW GFS / GFS MOS PROJECTIONS...WHICH INITIALIZED
AT 12Z WITH SURFACE DEWPOINT ERRORS OF AS MUCH AS 20
DEGREES...ERRORS WHICH RENDER THE MODEL MOSTLY USELESS FOR THIS
FORECAST CYCLE. OTHER MODELS WERE ALSO A LITTLE TOO LOW ON
DEWPOINTS...BUT RAW NAM NUMBERS (FOR BOTH T/TD) WERE ALIGNING VERY
CLOSE TO CURRENT OBSERVATIONS.
USING THESE NUMBERS AS GUIDANCE...AS WELL AS CONTINUED PATTERN
RECOGNITION...THERE IS GOOD REASON TO FORECAST ANOTHER NIGHT OF
FOG FOR THE ILN FORECAST AREA. WORKING AGAINST THE THREAT WILL BE
THAT THE CENTER OF THE HIGH WILL NOT BE DIRECTLY OVER THE REGION
(ALLOWING SOME LIGHT WIND FLOW)...AND THE VERY-SLIGHTLY-MODIFIED
AIR MASS MEANS THAT FOG MAY BE A LITTLE MORE SHALLOW THAN LAST
NIGHT. NONETHELESS...THE STABLE AIR MASS AND STRONG INVERSION WILL
CONTINUE TO SUPPORT A NEAR-SURFACE STABLE LAYER...AND STRATUS/FOG
DEVELOPMENT IS EXPECTED TO BEGIN QUICKLY AFTER SUNSET. FOG HAS
BEEN INCLUDED WITH EMPHASIS IN THE GRIDDED FORECAST AND THE
HAZARDOUS WEATHER OUTLOOK. THE ONLY REAL UNCERTAINTY IS IN THE FAR
SOUTHERN SECTIONS OF THE CWA...WHERE CONDITIONS CLEARED OUT MORE
QUICKLY THIS MORNING...AND HRRR VISIBILITY PROJECTIONS SUGGEST THE
DENSE FOG MAY STOP SHORT OF REACHING.
WITH LITTLE CHANGE TO THE AIR MASS...MIN TEMPS WERE KEPT VERY
CLOSE TO VALUES FROM LAST NIGHT. HOWEVER...WITH THE TIMING AND
PLACEMENT OF THE EVENTUAL PATCHES OF FOG/STRATUS TO DEVELOP
(EVENTUALLY BECOMING AT LEAST SOMEWHAT WIDESPREAD)...THE EXACT
MIN TEMPERATURE FORECAST FOR ANY GIVEN LOCATION HAS A SLIGHTLY
LOWER CONFIDENCE THAN USUAL.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/...
FOG WILL LIKELY BE IN PLACE FOR MOST OF THE AREA TO START SUNDAY
MORNING. WITH A SWITCH TO SOUTHERLY NEAR-SURFACE FLOW...AND A VERY
SLIGHTLY WARMER/DRIER AIR MASS OVERALL COMPARED TO THIS
MORNING...THE EXPECTATION IS THAT FOG/STRATUS WILL DISSIPATE A
LITTLE QUICKER THAN OCCURRED TODAY. THE MAX TEMPERATURE FORECAST
WAS STILL KEPT SOMEWHAT CONSERVATIVE DUE TO THE POTENTIAL FOR
CLOUDS...BUT THE ENTIRE CWA WILL LIKELY MAKE IT INTO THE MIDDLE TO
UPPER 40S ONCE THINGS CLEAR OUT...WITH LOWER 50S IN THE FAR
SOUTHEAST (WHERE SUNNY CONDITIONS ARE EXPECTED EVEN SOONER).
ON SUNDAY NIGHT...A WELL-DEFINED UPPER LOW WILL MOVE EAST THROUGH
THE SOUTHERN GREAT LAKES / NORTHERN OHIO VALLEY. THIS LOW IS NOT
PARTICULARLY STRONG...AND ASIDE FROM AN UNIMPRESSIVE SURFACE WIND
SHIFT...LOW-LEVEL FORCING IS EXPECTED TO BE VERY WEAK AS WELL.
THE COOLING AIR ALOFT WILL FINALLY HELP TO ERODE SOME OF THE
STRONG INVERSION...BUT MOISTURE WILL REMAIN FAIRLY SHALLOW...AND
WIDESPREAD PRECIPITATION IS NOT EXPECTED TO DEVELOP. THE CURRENT
RANGE OF POP VALUES (10-40 PERCENT FROM NORTH TO SOUTH) STILL
MATCHES FORECAST EXPECTATIONS NICELY...WITH TIMING REFINED BASED
ON 12Z RUNS...AND THE AREA SLIGHTLY EXPANDED. BECAUSE OF THE
INVERSION...THIS PRECIPITATION WILL LIKELY BE ALL RAIN...EVEN
THOUGH SURFACE TEMPERATURES EARLY MONDAY MORNING WILL BE IN THE
MID 30S.
SOME WEAK COLD ADVECTION BEHIND THE UPPER LOW WILL KEEP
TEMPERATURES IN THE MID 40S ON MONDAY...NEAR OR JUST ABOVE
NORMAL.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
A COUPLE OF PROGRESSIVE S/WVS ARE FORECAST TO TRAVERSE FROM WEST TO
EAST ACROSS THE GREAT LAKES AND OHIO VALLEY REGION DURING THE EARLY
TO MID WEEK PERIOD. TUESDAY/S DISTURBANCE IS EXPECTED TO BE WEAK AND
MOISTURE STARVED...SO ONLY CLOUDS ARE FORECAST. THE SECOND
DISTURBANCE FOR WEDNESDAY/WEDNESDAY NIGHT IS A LITTLE STRONGER AND
HAS DEEPER MOISTURE IN ASSOCIATION WITH A COLD FRONT. HAVE CONTINUE
WITH A CHANCE OF SHOWERS DURING THIS TIME FRAME.
THE FORECAST BECOMES LESS CLEAR AS WE HEAD INTO THE END OF THE
WEEK...ESPECIALLY IN REGARDS TO AREAL COVERAGE AND PROBABILITY OF
PCPN. THE FLOW DOES BECOME MORE AMPLIFIED WITH A LARGE SCALE MID
LEVEL TROUGH DIGGING OUT ACROSS THE WESTERN U.S. AND RIDGING
DEVELOPING OVER THE EASTERN U.S. S/WV ENERGY FOR THURSDAY/FRIDAY
VARIOUS AMONGST THE MODELS IN TERMS OF HOW STRONG/DEEP IT WILL BE AS
IT PASSES THROUGH THE GREAT LAKES. HAVE KEPT POPS ON THE LOW SIDE
DUE TO HIGH UNCERTAINTY. FOR SATURDAY...LOOKS LIKE MID LEVEL RIDGING
AND A WARM FRONT WILL LIFT THROUGH OUR REGION. WARMER TEMPERATURES
AND SOME WAA SHOWERS WILL BE POSSIBLE.
IT WILL CONTINUE TO BE WARMER THAN NORMAL THROUGH THE PERIOD WITH
TEMPERATURES WARMING INTO THE UPPER 50S TO THE LOWER 60S BY THE
WEEKEND...WHICH IS SOME 20 DEGREES ABOVE NORMAL FOR MID DECEMBER.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
LIFR ST/FOG ALMOST DISSIPATED ALL THE WAY THIS AFTERNOON...BUT
LEFT AN AREA BETWEEN TZR-SGH-ILN. AS THE SUN SAT THIS
EVENING...THE AREA QUICKLY EXPANDED BACK OUT AND IS EXPECTED TO
CONTINUE TO EXPAND OVERNIGHT AS THE LOW LEVEL MOISTURE REMAINS
TRAPPED UNDER A SUBSIDENCE INVERSION. PRETTY CONFIDENT THAT THE
LIFR CONDITIONS WILL AFFECT THE NRN TAFS...BUT NOT QUITE AS
CONFIDENT IN WHAT WILL HAPPEN AT CVG/LUK. WILL THE FOG BUILD THAT
FAR SOUTH. WENT WITH IFR VSBYS IN A TEMPO GROUP AT CVG AFT 06Z TO
SHOW THIS UNCERTAINTY.
FOG SHOULD BE SLOW TO BURN OFF SUNDAY MORNING...PROBABLY LINGERING
MOST OF THE MORNING. RETURN FLOW ON SUNDAY SHOULD HELP THE BREAK
UP OF THE FOG AS COMPARED TO TODAY.
IN THE EXTENDED CVG TAF...VFR CIGS AROUND 4KFT ARE EXPECTED TO
REACH THE AREA AS H8 MOISTURE IS PULLED NORTH AHEAD OF A DIGGING
H5 LOW.
OUTLOOK...MVFR CEILINGS POSSIBLE MONDAY INTO TUESDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...DENSE FOG ADVISORY UNTIL 10 AM EST SUNDAY FOR OHZ026-044-045-
051>054-061>064-071>073-080.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...HATZOS
NEAR TERM...HATZOS
SHORT TERM...HATZOS
LONG TERM...HICKMAN
AVIATION...SITES
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
1208 PM EST FRI DEC 4 2015
.SYNOPSIS...
SURFACE HIGH PRESSURE OVER THE MID MISSISSIPPI VALLEY WILL MOVE
SLOWLY EAST ACROSS THE OHIO VALLEY AND MOVE OFF THE MID ATLANTIC
COAST SUNDAY. THIS WILL ALLOW AN UPPER LEVEL TROUGH TO MOVE
ACROSS THE OHIO VALLEY EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
UPDATE...LOW STRATUS EVOLVING LARGELY AS EXPECTED. SATELLITE DOES
SHOW THE THINNING HINTED AT ON THE HRRR ACROSS NERN INDIANA AND
NWRN OH. DID ADJUST SKY GRIDS THERE JUST A BIT TO BE MORE
OPTIMISTIC FOR GETTING SUN INTO THE AREA FOR THE
AFTERNOON(...ANTICIPATED TO OCCUR FROM MID AFTERNOON ON). ALSO
THINNING AS EXPECTED ALONG THE EASTERN EDGE WHICH HAS ERODED
CLOUDS IN SERN MAHONING COUNTY AS WELL AS A PORTION OF STARK AND
HOLMES COUNTY. THIS WILL LIKELY PERSIST THROUGH THE AFTERNOON BUT
NOT OPTIMISTIC FOR A LARGE SCALE CLEARING FROM THE SOUTHEAST JUST
YET. EARLIER UPDATE ALSO INCLUDED A TEMPERATURE DECREASE FOR THE
AFTERNOON AND WILL REMAIN CLOSE TO THOSE NUMBERS.
ORIGINAL DISCUSSION...
FORECAST PROBLEM OF THE DAY IS HOW FAST THE CLOUD DECK ACROSS THE
CENTRAL AND EASTERN LAKES WILL ERODE. NONE OF THE MODELS HAVE A
CLUE ABOUT THE CLOUD COVER SINCE INVERSION TRAPPING MOISTURE BELOW
925MB. THERE ARE A FEW CLOUD BREAKS NOW...BUT THE 925 MB RIDGE AXIS
DOESNT REACH NW OHIO UNTIL THIS AFTERNOON SO HAVE SLOWED THE TIMING
OF THE CLOUD DECK UNTIL THIS AFTERNOON. IN FACT DO NOT THINK THE
EAST WILL TOTALLY CLEAR OUT UNTIL TONIGHT. AS A RESULT LOWER
FORECAST HIGHS A FEW DEGREES.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/...
LAST REMAINING CLOUDS IN THE EAST SHOULD CLEAR OUT OVERNIGHT AS
THE RIDGE FINALLY MOVES OVER THE FORECAST AREA. SURFACE RIDGE
SHIFTS EAST OF THE AREA SATURDAY ALLOWING FOR A WARMUP. TEMPS
SHOULD WARM INTO THE UPPER 40S TO LOWER 50S THIS WEEKEND...WHICH
IS ROUGHLY 5-10 DEGREES ABOVE NORMAL FOR EARLY DECEMBER. MODELS
CONTINUE TO MOVE THE HIGH OFF THE MID ATLANTIC COAST EARLY SUNDAY.
THIS WILL ALLOW AN UPPER LEVEL TROUGH TO MOVE ACROSS THE OHIO
VALLEY ON MONDAY. BEST MOISTURE REMAINS WELL SOUTH OF THE FORECAST
AREA SO WILL CONTINUE WITH A DRY FORECAST THROUGH THE PERIOD.
&&
.LONG TERM /TUESDAY THROUGH THURSDAY/...
UNUSUALLY QUIET WEATHER WILL CONTINUE DURING THE LONG TERM PERIOD AS
HIGH PRESSURE AT THE SURFACE IS EXPECTED TO DOMINATE. HAVE MADE
ONLY MINOR CHANGES TO THE FORECAST. SOME MODEL DIFFERENCES BEGIN TO
CROP UP AT THE VERY END OF THE FORECAST PERIOD BUT WILL LET LATER
SHIFTS DEAL WITH THAT. TEMPERATURES DURING THE PERIOD WILL AVERAGE
5 TO 10 DEGREES ABOVE NORMAL WITH PARTLY CLOUDY SKIES MUCH OF THE
TIME.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
A SMALL AREA OF CLEARING HAS MADE IT`S WAY TO NE OHIO. IT SHOULD
LINGER OVER KCAK FOR ANOTHER HOUR AND AT KYNG FOR A COUPLE OF
HOURS. AFTER THAT IFR/MVFR CIGS WILL OVERSPREAD THE AREA AGAIN. IT
REMAINS VERY DRY ALOFT BUT THE BOUNDARY LAYER IS MOIST. TILL WE
GET ENOUGH MIXING THE LOW CLOUDS WILL PERSIST. BEST GUESS NOW IS
THAT THE CLOUDS WILL BEGIN TO BREAK UP AROUND MIDDAY. WILL KEEP
THE WESTERN SITES IFR TILL THEN AND BRING IFR INTO KCAK AND KYNG
IN A FEW HOURS. THERE SHOULD BE JUST ENOUGH DOWNSLOPING SW FLOW TO
KEEP CIGS AT KCLE AND KERI MVFR. ONCE THE CLOUDS BREAK UP SKIES
THE REMAINDER OF THE PERIOD SHOULD BE MAINLY CLEAR. SW TO WSW FLOW
WILL CONTINUE. WINDS SHOULD GRADUALLY LESSEN TODAY.
OUTLOOK...VFR CONDITIONS INTO EARLY NEXT WEEK AS HIGH PRESSURE
REMAINS IN CONTROL.
&&
.MARINE...
NO SIGNIFICANT CHANGES TO THE MARINE FORECASTS THIS
MORNING. MARGINAL SMALL CRAFT CONDITIONS WILL CONTINUE IN THE EAST
TODAY SO WILL LEAVE THE HEADLINES AS IS. HIGH PRESSURE WILL BUILD
OVER THE LAKE FROM THE SOUTH OVER THE WEEKEND. THIS WILL MAINTAIN A
LIGHT W TO SW FLOW. THE HIGH WILL EVENTUALLY LIFT OFF TO THE
NORTHEAST EARLY NEXT WEEK WITH VARIABLE FLOW UNDER 15 KNOTS
CONTINUING.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
LEZ147>149.
&&
$$
SYNOPSIS...DJB
NEAR TERM...DJB/TK
SHORT TERM...DJB
LONG TERM...KUBINA
AVIATION...KUBINA
MARINE...KUBINA
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
904 AM EST FRI DEC 4 2015
.SYNOPSIS...
SURFACE HIGH PRESSURE OVER THE MID MISSISSIPPI VALLEY WILL MOVE
SLOWLY EAST ACROSS THE OHIO VALLEY AND MOVE OFF THE MID ATLANTIC
COAST SUNDAY. THIS WILL ALLOW AN UPPER LEVEL TROUGH TO MOVE
ACROSS THE OHIO VALLEY EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
UPDATE...LOW STRATUS TRAPPED UNDER AN INVERSION REMAINS STUCK
ACROSS THE AREA THIS MORNING. THERE IS A DRY SLOT WITH THE EDGE
FROM ROUGHLY KCMH TO KYNG. HOWEVER THE CLOUD LINE IS EITHER
STATIONARY OR DRIFTING SLOWLY EAST. BIG QUESTION IS WHETHER IT
ERODES TOWARD THE WEST OR CONTINUES TO DRIFT SLOWLY EAST AS IT
ERODES. GIVEN THE STRENGTH OF THE INSOLATION (INCOMING SOLAR
RADIATION)...AM NOT OPTIMISTIC. ON THE OTHER SIDE...THE WESTERN
EDGE IS WELL WEST AND NORTHWEST ALONG THE LAKE MICHIGAN SHORE.
FOLLOWING THE HRRR THIS DRIFTS EAST-SOUTHEAST WITH CLEARING INTO
NWRN OHIO MID/LATE AFTERNOON. THE BIG TAKE HERE IS THAT FOR MOST
OF THE AREA...CLOUDS WILL LIKELY BE THE FLAVOR OF THE DAY.
ORIGINAL DISCUSSION...
FORECAST PROBLEM OF THE DAY IS HOW FAST THE CLOUD DECK ACROSS THE
CENTRAL AND EASTERN LAKES WILL ERODE. NONE OF THE MODELS HAVE A
CLUE ABOUT THE CLOUD COVER SINCE INVERSION TRAPPING MOISTURE BELOW
925MB. THERE ARE A FEW CLOUD BREAKS NOW...BUT THE 925 MB RIDGE AXIS
DOESNT REACH NW OHIO UNTIL THIS AFTERNOON SO HAVE SLOWED THE TIMING
OF THE CLOUD DECK UNTIL THIS AFTERNOON. IN FACT DO NOT THINK THE
EAST WILL TOTALLY CLEAR OUT UNTIL TONIGHT. AS A RESULT LOWER
FORECAST HIGHS A FEW DEGREES.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/...
LAST REMAINING CLOUDS IN THE EAST SHOULD CLEAR OUT OVERNIGHT AS
THE RIDGE FINALLY MOVES OVER THE FORECAST AREA. SURFACE RIDGE
SHIFTS EAST OF THE AREA SATURDAY ALLOWING FOR A WARMUP. TEMPS
SHOULD WARM INTO THE UPPER 40S TO LOWER 50S THIS WEEKEND...WHICH
IS ROUGHLY 5-10 DEGREES ABOVE NORMAL FOR EARLY DECEMBER. MODELS
CONTINUE TO MOVE THE HIGH OFF THE MID ATLANTIC COAST EARLY SUNDAY.
THIS WILL ALLOW AN UPPER LEVEL TROUGH TO MOVE ACROSS THE OHIO
VALLEY ON MONDAY. BEST MOISTURE REMAINS WELL SOUTH OF THE FORECAST
AREA SO WILL CONTINUE WITH A DRY FORECAST THROUGH THE PERIOD.
&&
.LONG TERM /TUESDAY THROUGH THURSDAY/...
UNUSUALLY QUIET WEATHER WILL CONTINUE DURING THE LONG TERM PERIOD AS
HIGH PRESSURE AT THE SURFACE IS EXPECTED TO DOMINATE. HAVE MADE
ONLY MINOR CHANGES TO THE FORECAST. SOME MODEL DIFFERENCES BEGIN TO
CROP UP AT THE VERY END OF THE FORECAST PERIOD BUT WILL LET LATER
SHIFTS DEAL WITH THAT. TEMPERATURES DURING THE PERIOD WILL AVERAGE
5 TO 10 DEGREES ABOVE NORMAL WITH PARTLY CLOUDY SKIES MUCH OF THE
TIME.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
A SMALL AREA OF CLEARING HAS MADE IT`S WAY TO NE OHIO. IT SHOULD
LINGER OVER KCAK FOR ANOTHER HOUR AND AT KYNG FOR A COUPLE OF
HOURS. AFTER THAT IFR/MVFR CIGS WILL OVERSPREAD THE AREA AGAIN. IT
REMAINS VERY DRY ALOFT BUT THE BOUNDARY LAYER IS MOIST. TILL WE
GET ENOUGH MIXING THE LOW CLOUDS WILL PERSIST. BEST GUESS NOW IS
THAT THE CLOUDS WILL BEGIN TO BREAK UP AROUND MIDDAY. WILL KEEP
THE WESTERN SITES IFR TILL THEN AND BRING IFR INTO KCAK AND KYNG
IN A FEW HOURS. THERE SHOULD BE JUST ENOUGH DOWNSLOPING SW FLOW TO
KEEP CIGS AT KCLE AND KERI MVFR. ONCE THE CLOUDS BREAK UP SKIES
THE REMAINDER OF THE PERIOD SHOULD BE MAINLY CLEAR. SW TO WSW FLOW
WILL CONTINUE. WINDS SHOULD GRADUALLY LESSEN TODAY.
OUTLOOK...VFR CONDITIONS INTO EARLY NEXT WEEK AS HIGH PRESSURE
REMAINS IN CONTROL.
&&
.MARINE...
NO SIGNIFICANT CHANGES TO THE MARINE FORECASTS THIS
MORNING. MARGINAL SMALL CRAFT CONDITIONS WILL CONTINUE IN THE EAST
TODAY SO WILL LEAVE THE HEADLINES AS IS. HIGH PRESSURE WILL BUILD
OVER THE LAKE FROM THE SOUTH OVER THE WEEKEND. THIS WILL MAINTAIN A
LIGHT W TO SW FLOW. THE HIGH WILL EVENTUALLY LIFT OFF TO THE
NORTHEAST EARLY NEXT WEEK WITH VARIABLE FLOW UNDER 15 KNOTS
CONTINUING.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
LEZ147>149.
&&
$$
SYNOPSIS...DJB
NEAR TERM...DJB/TK
SHORT TERM...DJB
LONG TERM...KUBINA
AVIATION...KUBINA
MARINE...KUBINA
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
358 AM EST FRI DEC 4 2015
.SYNOPSIS...
A LARGE AREA OF HIGH PRESSURE WILL BUILD ACROSS THE EASTERN CONUS
FOR THE WEEKEND AND INTO EARLY NEXT WEEK...SUPPLYING FAIR AND
MILDER WEATHER WITH LIGHT WIND.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
LOW LVL MOISTURE TRAPPED BENEATH SHARP INVERSION RESULTING IN
PERSISTENT LOW CLOUDS ACROSS CENTRAL PA EARLY THIS AM. SATL LOOP
AT 06Z INDICATING SOME BREAKS IN THE OVERCAST ACROSS THE LOWER
SUSQ VALLEY AND EXPECT THE CLEARING TREND TO WORK NWRD EARLY THIS
MORNING...AS INVERSION HGT LOWERS. NEAR TERM MDL SOUNDINGS SUPPORT
MCLEAR SKIES FROM KUNV/KAOO EASTWARD BY DAWN...WHILE STRATOCU
LINGERS ACROSS THE ALLEGHENY MTNS.
HAVE ZEROED OUT THE POPS EARLY THIS MORNING...AS MOISTURE LAYER IS
TOO SHALLOW TO SUPPORT PRECIP. HAVE ALSO RAISED MIN TEMPS
OVERNIGHT...GIVEN CLOUD COVER AND PERSISTENT BREEZE. BLEND OF LAMP
AND LATEST HRRR DATA SUPPORT READINGS IN THE 30S AT DAWN.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM SATURDAY/...
NEAR SFC FLOW WILL BECOME ANTICYCLONIC ACROSS THE FCST AREA BY
MIDDAY AS A LARGE SFC HIGH BUILDS NE FROM THE OHIO RIVER VALLEY.
LINGERING...SHALLOW SCT-BKN STRATO CU MAY PERSIST INTO THE
AFTERNOON ACROSS THE NRN MTNS. HOWEVER...EXPECT A DECENT AMOUNT OF
SUNSHINE ELSEWHERE ACROSS CENTRAL AND SOUTHERN PENN AFTER A PARTLY
TO MOSTLY CLOUDY START TO THE DAY.
WINDS WILL BE LESS THAN THURSDAY...BUT SOME WESTERLY GUSTS INTO
THE MID TEENS AREA STILL POSSIBLE.
TEMPS WILL BE A FEW DEG F HIGH THAN THURSDAY ACROSS MUCH OF THE
FCST AREA /WHICH WILL TURN OUT TO BE NEAR TO SLIGHTLY ABOVE
NORMAL/. MAXES ON FRIDAY WILL VARY FROM THE U30S OVER THE HIGHEST
ELEVATIONS TO AROUND 50F IN THE FAR SE.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
A SPLIT FLOW PATTERN IS FCST OVER THE LOWER 48 THRU THE MEDIUM
RANGE PERIOD...WITH RATHER MILD TEMPERATURES FOR EARLY DECEMBER
ANTICIPATED AS A PACIFIC AIRMASS MIGRATES FROM WEST TO EAST.
RIDGING AT THE SURFACE AND ALOFT WILL DOMINATE THE REGIONAL
WEATHER PATTERN WITH HIGH CONFIDENCE IN DRY WEATHER THROUGH
MONDAY.
THE KEY FEATURE HEADING INTO THE MIDDLE OF NEXT WEEK WILL BE A
MID LEVEL SYSTEM EVOLVING EASTWARD FROM THE ROCKIES AND POSSIBLY
CUTTING OFF SOMEWHERE BETWEEN TEXAS AND THE OHIO VALLEY. GIVEN THE
LARGE SPREAD AND MEDIUM RANGE MODEL `LIMBO` WILL STAY CLOSE TO
CONTINUITY. CONFIDENCE IS LOW REGARDING PCPN RISK AROUND THE
MIDDLE PART OF NEXT WEEK: A WELL-DEFINED LOW IS FORECAST BY MOST
GUID TO FORM JUST OFF THE EAST COAST AS THE MID LEVEL LOW
INTERACTS WITH TROPICAL MOISTURE. HOWEVER...THE LOW MAY BE FAR
ENOUGH TO THE S/E OF THE STATE TO KEEP IT DRY. ONLY SOME LOW POPS
WILL CONTINUE TO BE MENTIONED - MAINLY FOR THE SE FROM MON NITE-
TUE NIGHT.
&&
.AVIATION /09Z FRIDAY THROUGH TUESDAY/...
LOW LVL MOISTURE TRAPPED BENEATH SHARP INVERSION RESULTING IN
PERSISTENT LOW CLOUDS ACROSS CENTRAL PA EARLY THIS AM...WITH MVFR
CIGS IMPACTING CENTRAL MTNS FROM KJST-KAOO-KUNV AND IFR CIGS IN
THE NW MTNS INCLUDING KBFD. SATL LOOP INDICATING SOME BREAKS IN
THE OVERCAST ACROSS THE LOWER SUSQ VALLEY...AND EXPECT THE
CLEARING TREND TO WORK NWRD EARLY THIS MORNING AS INVERSION HGT
LOWERS. NEAR TERM MDL SOUNDINGS SUPPORT MCLEAR SKIES EAST OF
KUNV/KAOO BY DAWN...WHILE STRATOCU LINGERS ACROSS THE ALLEGHENY
MTNS.
THE FAIRLY SHALLOW STRATOCU CLOUDS WILL STAY IN THE IFR RANGE
THROUGH THE MID MORNING HOURS FRIDAY ACROSS THE NW MTNS. MVFR
STRATOCU ACROSS THE CENTRAL RIDGE AND VALLEY REGION WILL ERODE
AROUND 14-15Z...WHILE THE SE WILL SEE PRIMARILY VFR CONDITIONS ON
FRI. BFD WILL IMPROVE TO VFR BY EARLY AFTERNOON.
AS HIGH PRES APPROACHES FROM THE WEST...WINDS WILL REMAIN UP A BIT
OVERNIGHT AT SPEEDS AROUND 8-10KTS...WITH GUSTS TO 15-20 IN
SPOTS. THESE PERSIST INTO LATE MORNING FRI BEFORE DECREASING.
OUTLOOK...
SAT-MON...NO SIG WX EXPECTED.
TUE...CHANCE OF MVFR CIGS MAINLY ACROSS THE SERN 1/2 OF PENN.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...FITZGERALD
SHORT TERM...DANGELO/LAMBERT
LONG TERM...GARTNER/STEINBUGL
AVIATION...RXR
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
120 AM EST FRI DEC 4 2015
.SYNOPSIS...
A LARGE AREA OF HIGH PRESSURE WILL BUILD ACROSS THE EASTERN CONUS
FOR THE WEEKEND AND INTO EARLY NEXT WEEK...SUPPLYING FAIR AND
MILDER WEATHER WITH LIGHT WIND.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
LOW LVL MOISTURE TRAPPED BENEATH SHARP INVERSION RESULTING IN
PERSISTENT LOW CLOUDS ACROSS CENTRAL PA EARLY THIS AM. SATL LOOP
AT 06Z INDICATING SOME BREAKS IN THE OVERCAST ACROSS THE LOWER
SUSQ VALLEY AND EXPECT THE CLEARING TREND TO WORK NWRD EARLY THIS
MORNING...AS INVERSION HGT LOWERS. NEAR TERM MDL SOUNDINGS SUPPORT
MCLEAR SKIES FROM KUNV/KAOO EASTWARD BY DAWN...WHILE STRATOCU
LINGERS ACROSS THE ALLEGHENY MTNS.
HAVE ZEROED OUT THE POPS EARLY THIS MORNING...AS MOISTURE LAYER IS
TOO SHALLOW TO SUPPORT PRECIP. HAVE ALSO RAISED MIN TEMPS
OVERNIGHT...GIVEN CLOUD COVER AND PERSISTENT BREEZE. BLEND OF LAMP
AND LATEST HRRR DATA SUPPORT READINGS IN THE 30S AT DAWN.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM SATURDAY/...
NEAR SFC FLOW WILL BECOME ANTICYCLONIC ACROSS THE FCST AREA BY
MIDDAY AS A LARGE SFC HIGH BUILDS NE FROM THE OHIO RIVER VALLEY.
LINGERING...SHALLOW SCT-BKN STRATO CU MAY PERSIST INTO THE
AFTERNOON ACROSS THE NRN MTNS. HOWEVER...EXPECT A DECENT AMOUNT OF
SUNSHINE ELSEWHERE ACROSS CENTRAL AND SOUTHERN PENN AFTER A PARTLY
TO MOSTLY CLOUDY START TO THE DAY.
WINDS WILL BE LESS THAN THURSDAY...BUT SOME WESTERLY GUSTS INTO
THE MID TEENS AREA STILL POSSIBLE.
TEMPS WILL BE A FEW DEG F HIGH THAN THURSDAY ACROSS MUCH OF THE
FCST AREA /WHICH WILL TURN OUT TO BE NEAR TO SLIGHTLY ABOVE
NORMAL/. MAXES ON FRIDAY WILL VARY FROM THE U30S OVER THE HIGHEST
ELEVATIONS TO AROUND 50F IN THE FAR SE.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
A SPLIT FLOW PATTERN IS FCST OVER THE LOWER 48 THRU THE MEDIUM
RANGE PERIOD...WITH RATHER MILD TEMPERATURES FOR EARLY DECEMBER
ANTICIPATED AS A PACIFIC AIRMASS MIGRATES FROM WEST TO EAST.
RIDGING AT THE SURFACE AND ALOFT WILL DOMINATE THE REGIONAL
WEATHER PATTERN WITH HIGH CONFIDENCE IN DRY WEATHER THROUGH
MONDAY.
THE KEY FEATURE HEADING INTO THE MIDDLE OF NEXT WEEK WILL BE A
MID LEVEL SYSTEM EVOLVING EASTWARD FROM THE ROCKIES AND POSSIBLY
CUTTING OFF SOMEWHERE BETWEEN TEXAS AND THE OHIO VALLEY. GIVEN THE
LARGE SPREAD AND MEDIUM RANGE MODEL `LIMBO` WILL STAY CLOSE TO
CONTINUITY. CONFIDENCE IS LOW REGARDING PCPN RISK AROUND THE
MIDDLE PART OF NEXT WEEK: A WELL-DEFINED LOW IS FORECAST BY MOST
GUID TO FORM JUST OFF THE EAST COAST AS THE MID LEVEL LOW
INTERACTS WITH TROPICAL MOISTURE. HOWEVER...THE LOW MAY BE FAR
ENOUGH TO THE S/E OF THE STATE TO KEEP IT DRY. ONLY SOME LOW POPS
WILL CONTINUE TO BE MENTIONED - MAINLY FOR THE SE FROM MON NITE-
TUE NIGHT.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
UPPER TROUGH AND COLDER AIR ALOFT SUPPORTING SNOW SHOWERS CONTINUE
TO LIFT NE TOWARD NEW ENGLAND TONIGHT. SNOW SHOWERS HAVE
RESUMED...BRINGING LIFR CONDITIONS TO BFD AND MVFR CIGS THROUGH
THE OTHER CENTRAL AND WESTERN TAF SITES. THIS LOW STRATOCU WILL
CONTINUE THROUGH MOST OF THE OVERNIGHT PERIOD...WITH IFR CIGS
POSSIBLE AT JST...MAINLY AFTER 05Z.
THE FAIRLY SHALLOW STRATO CU CLOUDS WILL STAY IN THE IFR RANGE
THROUGH THE MID MORNING HOURS FRIDAY ACROSS THE NRN AND WRN MTNS
OF PENN...AND THEIR BASES WILL EVEN LOWER A FEW HUNDRED FEET.
BKN-OVC STRATO CU ACROSS THE CENTRAL RIDGE AND VALLEY REGION WILL
BE MAINLY MVFR THROUGH 12Z FRI...WHILE THE KMDT AND KLNS AREA SEE
PRIMARILY VFR SCT CLOUDS WITH BRIEF MVFR BKN CIGS POSSIBLE.
A MODERATELY TIGHT PRES GRADIENT IN WAKE OF THE DEPARTING STORM
SYSTEM WILL MAINTAIN GUSTY WNW WINDS IN THE UPPER TEEN TO LOWER 20
KT RANGE THROUGH THE FIRST HALF OF THE EVENING...BEFORE THE WIND
DECREASES SLIGHTLY OVERNIGHT AS HIGH PRES APPROACHES FROM THE
WEST.
EXPECT MAINLY VFR AT MOST LOCATIONS AFTER 15Z FRIDAY...CURRENT
MODELS SHOW BFD IMPROVING TO VFR BY EARLY AFTERNOON.
OUTLOOK...
SAT-MON...NO SIG WX EXPECTED.
TUE...CHANCE OF MVFR CIGS MAINLY ACROSS THE SERN 1/2 OF PENN.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...FITZGERALD
SHORT TERM...DANGELO/LAMBERT
LONG TERM...GARTNER/STEINBUGL
AVIATION...LAMBERT/CERU
AREA FORECAST DISCUSSION
NWS SEATTLE WA
408 PM PST SAT DEC 5 2015
.SYNOPSIS...
AN ACTIVE WEATHER PATTERN TAKING SHAPE ACROSS THE REGION FOR THE
NEXT SEVERAL DAYS. SATELLITE IMAGERY SHOWS A SERIES OF SYSTEMS
ACROSS THE PACIFIC. A LARGE UPPER LEVEL LOW OFF TO THE WEST OF THE
AREA WILL SERVE AS THE FOCUS FOR A SERIES OF WEATHER SYSTEMS TO
BRING RAIN...WIND...AND HIGH SURF TO THE AREA. SEVERAL INCHES OF
RAIN ARE POSSIBLE IN MANY AREAS THROUGH THE MIDDLE OF THIS COMING
WEEK.
&&
.SHORT TERM...
RAIN CONTINUES ACROSS THE AREA THIS AFTERNOON. RADAR SHOWS
WIDESPREAD LIGHT TO MODERATE RAIN. WPC DISCUSSION HIGHLIGHTED
HEAVY RAINFALL RATES OVER FAVORED OROGRAPHIC AREAS IN THE
SOUTHWEST FACING OLYMPICS THROUGH THE LATE EVENING. WINDS GUSTED
UP TO 78 MPH AT CRYSTAL MOUNTAIN AND 55-60 MPH IN THE SAN JUANS
EARLIER...BUT HAVE SLOWLY COME DOWN. WIND ADVISORIES AND HIGH WIND
WARNING WILL CONTINUE EXCEPT IN EASTERN PUGET SOUND LOWLANDS WHERE
WIND SPEEDS HAVE NOT REACHED HIGH ENOUGH. SHORT TERM WIND
FORECASTS FROM HRRR DEPICTS WINDS STEADILY DECREASING OVER THE
NEXT FEW HOURS. RAIN WILL SLOWLY END OVER THE LATE SATURDAY/EARLY
SUNDAY TIME FRAME. THIS WILL LEAVE SUNDAY AS A BREAK IN THE ACTION
FOR MOST...WITH A BRIEF PERIOD OF DRY WEATHER BEFORE THE NEXT
SYSTEM MOVES INTO THE AREA BY SUNDAY EVENING AND OVERNIGHT. THEN
ADDITIONAL RAIN AND WIND WILL ACCOMPANY THE NEXT STORM AND SO HIGH
WIND WATCHES HAVE BEEN POSTED FOR THE COAST ALONG WITH HIGH SURF
ADVISORIES. JOHNSON
.LONG TERM...
PARADE OF SYSTEMS INTO THIS COMING WEEK WILL CONTINUE. THERE WILL
BE TIMING ISSUES AS IT IS DIFFICULT TO RESOLVE INDIVIDUAL SYSTEMS
AT THIS TIME. THE GENERAL THEME WILL BE PERIODS OF RAIN...HEAVY AT
TIMES...AND THE RUN TOTAL QPF FROM MODEL FORECASTS SHOWS SEVERAL
INCHES OF RAIN ACROSS THE AREA THROUGH MID-LATE WEEK. HYDRO ISSUES
IN TERMS OF RIVER RISES AND FLOODING WILL BE ON THE INCREASE OVER
THE NEXT FEW DAYS AS WELL AS LIKELY IMPACTS FROM WIND AS WELL.
JOHNSON
.AVIATION...
A STRONG WET FRONTAL SYSTEM JUST OFFSHORE IS SLOWLY APPROACHING
THE WA COAST. THE FRONT WILL MOVE ACROSS W WA LATE TONIGHT SO POOR
WEATHER WILL CONTINUE. STRONG A DEEP LOW OFFSHORE APPROACHING THE
CENTRAL B.C. COAST IS CAUSING STRONG PRESSURE GRADIENTS ACROSS W
WA WITH STRONG AND GUSTY SURFACE WINDS. LOW LEVEL WINDS ALOFT
AROUND 2500 FEET THROUGH THE GREATER PUGET SOUND REGION ARE
SOUTHERLY 25-40 KT.
LIGHT TO MODERATE RAIN COVERS ALL OF W WA THIS AFTERNOON. CIGS
REMAIN VFR AROUND OVC040-050 OVER THE AREA WITH VISIBILITY MAINLY 5-
10 MILES. CIGS ARE EXPECTED TO LOWER TO MVFR LATE TONIGHT AFTER
THE COLD FRONT HAS MOVED INLAND.
KSEA...VFR CIGS OVC040-050 WITH RAIN THROUGH TONIGHT. VISIBILITY 5
MILES OR BETTER. SURFACE WINDS WILL BE S 10-15 KT...BUT LOW LEVEL
WINDS AROUND 5000 FEET WILL BE S 40-55 KT. KAM
&&
.MARINE...A STRONG COLD FRONT JUST OFFSHORE WILL MOVE INLAND AND
WEAKEN TONIGHT WHILE THE MAIN 975 MB SURFACE LOW HEADS TOWARD THE
CENTRAL B.C. COAST. PRESSURE GRADIENTS ACROSS W WA WILL WEAKEN SOME
TONIGHT AND EARLY SUNDAY. ANOTHER STRONG COLD FRONT WILL APPROACH
THE REGION SUNDAY AFTERNOON AND EVENING BEFORE MOVING INLAND EARLY
MONDAY MORNING. ACTIVE WEATHER WILL CONTINUE THROUGH NEXT WEEK WITH
A SERIES OF FRONTAL SYSTEMS EXPECTED.
WINDS APPEAR TO BE WEAKENING LATE THIS AFTERNOON...BUT I WILL HOLD
ON TO THE STORM WARNINGS FOR A FEW MORE HOURS...UNTIL 7 PM THIS
EVENING. SO TONIGHT AND SUNDAY MORNING WILL BE A RELATIVE LULL IN
THE WINDS...EVEN THOUGH WINDS WILL REMAIN AT OR NEAR GALE FORCE
LEVELS OVER SOME WATERS THROUGH SUNDAY MORNING. THE NEXT STRONG
FRONTAL SYSTEM WAS APPROACHING 150W AT 23Z AND SHOULD MOVE E OF 130W
AND APPROACH THE AREA SUNDAY AFTERNOON. MODEL SOLUTIONS SEEM TO HAVE
WEAKENED SLIGHTLY...BUT STORM FORCE WINDS ARE STILL POSSIBLE OVER
THE COASTAL WATERS. GALES ARE LIKELY OVER THE INLAND WATERS OF THE N
INTERIOR. A STORM WATCH REMAINS POSTED FOR THE COAST AND GALES ARE
ALREADY POSTED FOR THE N INTERIOR WATERS.
A LARGE WESTERLY SWELL WILL BE APPROACHING THE AREA SUNDAY
NIGHT...THE LATEST WAVE WATCH MODEL SHOWS A WESTERLY SWELL OF 18 TO
22 FEET AT 16-17 SECONDS REACHING THE AREA SUNDAY NIGHT...AND
PEAKING AROUND MIDNIGHT. TOTAL SEAS OVER THE COASTAL WATERS WILL BE
MUCH LARGER THAN THIS...AS A 16-19 FOOT 11 SECOND SOUTHERLY SWELL
WILL BE MOVING NORTH OVER THE COASTAL WATERS AT THE SAME TIME. WHILE
THE TOTAL SEAS OFFSHORE WILL BE CLOSE TO 28 FEET...ONLY THE WESTERLY
PORTION WILL PRODUCE SIGNIFICANT SURF ALONG THE COAST. THE TIDE AT
TOKE POINT WILL BE LOW DURING THE HIGHEST SURF SUNDAY NIGHT. THE W
SWELL WILL BE DOWN TO AROUND 16 FEET DURING THE VERY HIGH TIDE LATE
MONDAY MORNING. KAM
&&
.HYDROLOGY...
THE SKOKOMISH RIVER IS BELOW FLOOD STAGE AND RISING THIS
AFTERNOON AND WILL CLIMB ABOVE FLOOD STAGE IN THE IMMEDIATE FUTURE.
TODAY. THE FLOOD WARNING REMAINS IN EFFECT.
THE INCOMING SERIES OF WET WEATHER SYSTEMS WILL BRING LOTS OF
PRECIPITATION TO THE MOUNTAINS -- TOTALS OF 6 TO 12 INCHES FOR
THE PERIOD SUNDAY THROUGH WEDNESDAY SHOULD BE COMMON. BUT THE
PATTERN WILL BE PROGRESSIVE...MEANING THERE WILL BE BREAKS BETWEEN
THE PERIODS OF HEAVY RAINFALL. IN ADDITION SNOW LEVELS SHOULD
REMAIN 7000 FT OR BELOW...AND THAT IS LOWER THAN WHAT NORMALLY
OCCURS IN A WESTERN WASHINGTON FLOODING SITUATION.
THE SKOKOMISH RIVER COULD FLOOD AT TIMES THROUGH LATE NEXT WEEK.
SOME MINOR FLOODING IS ALSO POSSIBLE ON THE OTHER RIVERS IN OUR
FORECAST AREA...BUT AT THIS TIME THE THREAT OF A SIGNIFICANT FLOOD
EVENT APPEARS TO BE RATHER LOW. MCDONNAL/JOHNSON
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...WINTER STORM WARNING UNTIL NOON PST SUNDAY FOR CASCADES OF
PIERCE AND LEWIS COUNTIES-CASCADES OF SNOHOMISH AND KING
COUNTIES-CASCADES OF WHATCOM AND SKAGIT COUNTIES.
WIND ADVISORY UNTIL 3 AM PST SUNDAY FOR ADMIRALTY INLET AREA-
WESTERN SKAGIT COUNTY-WESTERN WHATCOM COUNTY.
HIGH WIND WATCH FROM SUNDAY AFTERNOON THROUGH LATE SUNDAY NIGHT
FOR ADMIRALTY INLET AREA-SAN JUAN COUNTY-WESTERN SKAGIT
COUNTY-WESTERN WHATCOM COUNTY.
WIND ADVISORY UNTIL 9 PM PST THIS EVENING FOR CENTRAL COAST-
NORTH COAST.
HIGH WIND WATCH FROM SUNDAY AFTERNOON THROUGH LATE SUNDAY NIGHT
FOR CENTRAL COAST-NORTH COAST.
HIGH SURF ADVISORY FROM 4 PM SUNDAY TO 9 AM PST MONDAY FOR
CENTRAL COAST-NORTH COAST.
HIGH WIND WARNING UNTIL 7 PM PST THIS EVENING FOR SAN JUAN
COUNTY.
WIND ADVISORY FROM 7 PM THIS EVENING TO 3 AM PST SUNDAY FOR SAN
JUAN COUNTY.
WIND ADVISORY UNTIL 10 PM PST THIS EVENING FOR EASTERN STRAIT OF
JUAN DE FUCA.
PZ...SMALL CRAFT ADVISORY FOR ROUGH BAR UNTIL 10 AM PST MONDAY FOR
GRAYS HARBOR BAR.
STORM WATCH FROM SUNDAY AFTERNOON THROUGH LATE SUNDAY NIGHT FOR
COASTAL WATERS FROM CAPE FLATTERY TO JAMES ISLAND 10 TO 60
NM-COASTAL WATERS FROM CAPE FLATTERY TO JAMES ISLAND OUT 10
NM-COASTAL WATERS FROM JAMES ISLAND TO POINT GRENVILLE 10
TO 60 NM-COASTAL WATERS FROM JAMES ISLAND TO POINT
GRENVILLE OUT 10 NM-COASTAL WATERS FROM POINT GRENVILLE TO
CAPE SHOALWATER 10 TO 60 NM-COASTAL WATERS FROM POINT
GRENVILLE TO CAPE SHOALWATER OUT 10 NM.
STORM WARNING UNTIL 7 PM PST THIS EVENING FOR COASTAL WATERS
FROM CAPE FLATTERY TO JAMES ISLAND 10 TO 60 NM-COASTAL
WATERS FROM CAPE FLATTERY TO JAMES ISLAND OUT 10 NM-COASTAL
WATERS FROM JAMES ISLAND TO POINT GRENVILLE 10 TO 60 NM-
COASTAL WATERS FROM JAMES ISLAND TO POINT GRENVILLE OUT 10
NM-COASTAL WATERS FROM POINT GRENVILLE TO CAPE SHOALWATER
10 TO 60 NM-COASTAL WATERS FROM POINT GRENVILLE TO CAPE
SHOALWATER OUT 10 NM-EAST ENTRANCE U.S. WATERS STRAIT OF
JUAN DE FUCA-NORTHERN INLAND WATERS INCLUDING THE SAN JUAN
ISLANDS.
GALE WARNING FROM 7 PM THIS EVENING TO 1 PM PST SUNDAY FOR
COASTAL WATERS FROM CAPE FLATTERY TO JAMES ISLAND 10 TO 60
NM-COASTAL WATERS FROM CAPE FLATTERY TO JAMES ISLAND OUT 10
NM-COASTAL WATERS FROM JAMES ISLAND TO POINT GRENVILLE 10
TO 60 NM-COASTAL WATERS FROM JAMES ISLAND TO POINT
GRENVILLE OUT 10 NM-COASTAL WATERS FROM POINT GRENVILLE TO
CAPE SHOALWATER 10 TO 60 NM-COASTAL WATERS FROM POINT
GRENVILLE TO CAPE SHOALWATER OUT 10 NM.
GALE WARNING FROM 7 PM THIS EVENING TO 4 AM PST MONDAY FOR EAST
ENTRANCE U.S. WATERS STRAIT OF JUAN DE FUCA-NORTHERN INLAND
WATERS INCLUDING THE SAN JUAN ISLANDS.
SMALL CRAFT ADVISORY UNTIL NOON PST SUNDAY FOR WEST ENTRANCE
U.S. WATERS STRAIT OF JUAN DE FUCA.
GALE WARNING FROM NOON SUNDAY TO 4 AM PST MONDAY FOR WEST
ENTRANCE U.S. WATERS STRAIT OF JUAN DE FUCA.
SMALL CRAFT ADVISORY FROM 9 PM THIS EVENING TO 4 AM PST MONDAY
FOR CENTRAL U.S. WATERS STRAIT OF JUAN DE FUCA.
GALE WARNING UNTIL 9 PM PST THIS EVENING FOR CENTRAL U.S. WATERS
STRAIT OF JUAN DE FUCA.
SMALL CRAFT ADVISORY UNTIL 4 PM PST SUNDAY FOR ADMIRALTY INLET.
GALE WARNING FROM 4 PM SUNDAY TO 4 AM PST MONDAY FOR ADMIRALTY
INLET.
SMALL CRAFT ADVISORY UNTIL 10 AM PST MONDAY FOR PUGET SOUND AND
HOOD CANAL.
&&
$$
WWW.WEATHER.GOV/SEATTLE
YOU CAN SEE AN ILLUSTRATED VERSION OF THIS DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
1112 PM PST SAT DEC 5 2015
.SYNOPSIS...MODERATE AMOUNTS OF RAIN ARE FORECAST TO FALL ACROSS
THE NORTH BAY LATE SATURDAY NIGHT INTO SUNDAY MORNING. THE
INCOMING FRONTAL SYSTEM WILL WEAKEN RAPIDLY AS IT MOVES SOUTH OF
THE GOLDEN GATE ON SUNDAY AND RAINFALL AMOUNTS WILL BE VERY LIGHT
FROM SAN FRANCISCO SOUTHWARD. DRY AND MILD WEATHER IS FORECAST
FROM LATE SUNDAY THROUGH EARLY WEDNESDAY. THE NEXT PACIFIC WEATHER
SYSTEM WILL WILL LIKELY BE STRONGER AND BRING HEAVIER AND MORE
WIDESPREAD RAIN TO THE REGION FROM WEDNESDAY THROUGH THURSDAY
NIGHT. SHOWERS MAY LINGER INTO FRIDAY WITH ANOTHER SYSTEM POSSIBLE
NEXT WEEKEND.
&&
.DISCUSSION...AS OF 8:45 PM PST SATURDAY...THE INCOMING FRONTAL
BOUNDARY IS STARTING TO PUSH INLAND ALONG THE FAR NORTHERN CA
COAST THIS EVENING. IR SATELLITE SHOWS THAT THE SOUTHERN PORTION
OF THE FRONT...SOUTH OF ABOUT 37N...IS WEAK WITH VERY LITTLE COLD
AIR ADVECTION BEHIND IT. THIS IS CONSISTENT WITH MODEL DATA WHICH
SHOWS THE FRONT WEAKENING RAPIDLY AS IT PUSHES EASTWARD OVER THE
NEXT 18 HOURS AND ENCOUNTERS THE RIDGE CENTERED OVER THE SOUTHWEST
U.S.. PRECIPITATION TIMING HASN`T CHANGED WITH THE 00Z MODELS THAT
ARE IN THUS FAR. RAIN WILL BEGIN TO SPREAD INTO THE NORTH BAY
AROUND MIDNIGHT AND REACH SAN FRANCISCO BY SUNRISE. THE FRONTAL
BOUNDARY WILL THEN RAPIDLY DISSIPATE AS IT PRESSES SOUTH OF THE
GOLDEN GATE ON SUNDAY MORNING. THE SOUTHERN EXTENT OF RAINFALL
ON SUNDAY WILL PROBABLY AROUND WATSONVILLE AND GILROY. LIGHT RAIN
MAY LINGER ALONG THE DISSIPATING FRONTAL BOUNDARY INTO EARLY
SUNDAY AFTERNOON...BUT SHOULD MOSTLY END BY LATE AFTERNOON. THE
NAM CONTINUES TO BE THE WETTEST MODEL...BUT IT HAS REDUCED PRECIP
TOTALS COMPARED TO YESTERDAY`S 00Z RUN. THE LATEST NAM SHOWS AS
MUCH AS AN INCH IN THE NORTH BAY...WITH THE GFS AND ECMWF
FORECASTING MAXIMUM NORTH BAY RAINFALL AMOUNTS OF ONLY HALF THAT
MUCH. RAIN TOTALS SOUTH OF THE GOLDEN GATE ARE EXPECTED TO BE
BELOW A QUARTER OF AN INCH...WITH LESS THAN A TENTH OF AN INCH
EXPECTED FROM SAN JOSE SOUTH.
DRY AND MILD WEATHER IS FORECAST FROM LATE SUNDAY THROUGH AT LEAST
TUESDAY NIGHT AS AN UPPER RIDGE BUILDS OVER CENTRAL AND SOUTHERN
CALIFORNIA. THE RIDGE IS FORECAST TO BE DIRTY WITH CONSIDERABLE
HIGH CLOUDS EXPECTED TO STREAM ACROSS OUR REGION FROM TIME TO TIME
EARLY IN THE WEEK...ESPECIALLY IN THE NORTH.
THE NEXT SYSTEM IS FORECAST TO IMPACT OUR AREA FROM WEDNESDAY
THROUGH THURSDAY NIGHT. A PLUME OF MOIST AIR THAT WILL BE FLOWING
INTO THE PAC NW ON TUESDAY IS EXPECTED TO SAG AS FAR SOUTH AS THE
NORTH BAY BY WEDNESDAY. THIS WARM ADVECTION PRECIP WILL LIKELY
REMAIN CONFINED TO THE NORTH BAY ON WEDNESDAY. AN UPPER TROUGH
WILL THEN APPROACH THE NORTHERN CALIFORNIA COAST BY WEDNESDAY
NIGHT AND DRIVE PRECIPITATION SOUTH ACROSS THE REMAINDER OF OUR
FORECAST AREA WEDNESDAY NIGHT AND THURSDAY MORNING. ONCE THE UPPER
TROUGH REACHES THE COAST IT IS FORECAST TO DIG TO THE
SOUTHEAST...BRINGING A COLDER AND UNSTABLE AIRMASS ACROSS OUR AREA
FROM THE NORTHWEST. THIS WILL RESULT IN SCATTERED SHOWERS THURSDAY
AFTERNOON AND THURSDAY NIGHT...AND POSSIBLY INTO FRIDAY AS WELL.
THIS SYSTEM MAY ALSO PRODUCE LOCALLY STRONG AND GUSTY WINDS FROM
WEDNESDAY NIGHT THROUGH THURSDAY EVENING.
ANOTHER SYSTEM MAY BRING ADDITIONAL RAINFALL TO AT LEAST THE
NORTHERN PORTION OF OUR REGION NEXT WEEKEND.
&&
.AVIATION...AS OF 11:12 PM PST SATURDAY...VFR. SE WINDS. UPPER
TROUGH MOVES EAST OVER NORCAL TONIGHT THEN BROAD AND STRONG (FOR
DECEMBER) UPPER LEVEL RIDGING FORECAST THROUGH EARLY NEXT WEEK.
VICINITY OF KSFO...VFR/MVFR LATE TONIGHT/SUNDAY MORNING WITH LIGHT
RAIN POSSIBLE.
SFO BRIDGE APPROACH...SIMILAR TO KSFO.
MONTEREY BAY AREA TERMINALS...VFR.
&&
.MARINE...AS OF 9:12 PM PST SATURDAY...SOUTHERLY WINDS WILL
INCREASE OVER THE COASTAL WATERS AS A COLD FRONT SWEEPS THROUGH
THE REGION TONIGHT AND SUNDAY. THE GUSTY WINDS WILL BE STRONGEST
NORTH OF PIGEON POINT PRODUCING HAZARDOUS CONDITIONS. A LARGE LONG
PERIOD NORTHWESTERLY SWELL IS EXPECTED TO ENTER THE COASTAL WATERS
THIS SUNDAY PERSISTING INTO MONDAY. THIS SWELL WILL RESULT IN
LARGE BREAKING WAVES ALONG COASTAL REEFS AND SAND BARS.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.TNGT...SCA...PT ARENA TO PT REYES 0-10 NM
SCA...PT ARENA TO PIGEON PT 10-60 NM
SCA...PT REYES TO PIGEON PT 0-10 NM
SCA...ROUGH BAR ADVISORY FOR SF BAR FROM 3 AM
&&
$$
PUBLIC FORECAST: DYKEMA
AVIATION: CANEPA
MARINE: MM
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[top]
Area Forecast Discussion
National Weather Service Sacramento CA
935 PM PST SAT DEC 5 2015
.SYNOPSIS...
SEVERAL WEATHER SYSTEMS WILL BRING PERIODS OF RAIN AND MOUNTAIN SNOW
FOR THE UPCOMING WEEK.
&&
.DISCUSSION...
Frontal precip now moving inland with leading edge of the rain just
moving into the Wrn part of our CWA at 930 pm. By about midnight...
the leading edge of the rain should at least be along a RDD...RBL...STS
line. Rain expected to move into the SAC area by around 6-8 am...near
the start of the CIM. The HRRR accumulated precip shows some heavier
bands of rain from around BAB-OVE and NEwd from there into Wrn Plumas Co
where totals could equal/exceed 1.00-1.33 inches in the area of stronger
dynamics and orographics.
One thing we have adjusted this evening in the update was a little
higher PoPs in the I-80 Corridor for the Vly...and also lowering
snow levels some over the W Slope Siernev Sun morning due to the
very dry sub-cloud air mass. Dewpoints in the teens and 20s will
mean lower WBZs...and evaporative cooling at the onset of the
precip. BLU likely to start out as snow Sun morning perhaps turning to
rain/wet snow mix or light rain/drizzle later in the day. Still not
able to get significant snow accumulations out of this system and not
feeling confident in advsry level snow. This will have to be monitored/
contemplated overnite. JHM
.Previous Discussion...
A weather system is off the coast and the cold front will move
inland late tonight and Sunday morning. The system is not that
strong but could bring up to 0.40 inches of rain for the valley
and 0.25 to 1.00 inch of precipitation for the mountains. The
higher totals are expected from around Plumas County northward.
Snow levels look to start out around 4000 feet over the north to
around 5000 feet for the Western Slopes of the Sierra Nevada. The
snow levels may start out near advertised levels but should rise
during the late morning and afternoon hours. The bulk of the
system moves through in the morning and then weakens
significantly. Some lingering showers may continue into the early
evening hours...mainly over the mountains before ending. Several
inches of snow are likely below pass levels and over some of the
higher mountain highway roadways.
A couple of systems will move into the Pacific Northwest early next
week with zonal flow over Northern California. Most areas are
expected to remain dry other than the far northern sections of the
state which may get some light precipitation at times.
&&
.EXTENDED DISCUSSION (Wednesday THROUGH Saturday)
The extended forecast period looks wet and unsettled with a
significant storm system moving through Wednesday, Thursday and
into Friday. This potentially very wet system has a good Pacific
moisture plume with dynamics from a strong 150+kt jet. Models are
now in fairly good agreement with the general timing of
precipitation moving through the Coastal Range and into the
southern Cascades and northern Sacramento Valley by Wednesday
morning, then spreading across the most of the area by evening.
The heaviest precipitation looks like it will be on Thursday,
though exactly when is not clear yet due to model timing
differences. Current projections suggest snowfall amounts
exceeding 1 foot in the mountains, potentially double this over
higher peaks. Snow levels look to be around 5000 feet falling to
around 4000 feet.
Additional systems will bring the potential for more
precipitation through the rest of the week and into the weekend
with snow levels around or below 4000 feet. EK
&&
.AVIATION...
VFR conditions over Norcal thru about 10z-12z Sun...then rapidly
deteriorating conditions to widespread MVFR/IFR cigs/vsbys in
RA/BR after 12z Sun as Pacific cold front moves thru the area.
LIFR conditions in RA/SN/FG over Siernev with SW winds increasing
to over 35 kts over hyr trrn after 08z Sun. Cigs/vsbys gradually
improving to VFR after 00z Mon...but low stratus/fog expected to
redevelop late Sun nite and Mon morning.
&&
.STO Watches/Warnings/Advisories...
None.
&&
$$
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
450 AM EST SUN DEC 6 2015
.DISCUSSION...
TODAY-TONIGHT...HI PRES RIDGE SPANNING THE ERN SEABOARD WILL
CONTINUE TO INTERACT WITH A REMNANT FRONTAL TROF OVER THE FL
STRAITS/NRN BAHAMAS TO MAINTAIN A BRISK NE FLOW ACRS THE FL
PENINSULA. WINDS WILL GRADUALLY DIMINISH THRU THE DAY AS A SHORT
WAVE TROF OVER THE NATION`S MIDSECTION NUDGES THE RIDGE INTO THE W
ATLC WHERE IT WILL BEGIN TO MODIFY. THE USAF 915HZ PROFILER HAS
SHOWN A WEAKENING TREND IN THE H100-H85 WIND FIELD SINCE
07/00Z...DIMINISHING FROM 25-30KTS DOWN TO 20-25KTS.
DEEP MOISTURE OVER S FL WITH A SATURATED H100-H50 LYR ON THE 07/00Z
KMFL RAOB...PWAT VALUES ARND 2.1". RUC ANALYSIS SHOWS A SHARP
MOISTURE BOUNDARY EXTENDING FROM FT MYERS TO JUST N OF GRAND BAHAMA
ISLAND...PASSING JUST SOUTH OF LAKE OKEECHOBEE. MOISTURE DECREASES
RAPIDLY TO THE N AS PREVAILING WRLY WINDS ABV H85 HAVE PUSHED DRY
MID LVL AIR INTO CENTRAL FL. PWATS DECREASE TO 1.1"-1.2" AT
KXMR/KTBW THEN TO ARND 1.0" AT KJAX...MOST OF WHICH IS TRAPPED BLO A
SHARP SUBSIDENCE INVERSION IN THE H85-H70 LYR. RADAR HAS BEEN
DETECTING BANDS OF LIGHT SHRAS PUSHING ONSHORE FROM SEBASTIAN INLET
SWD....MOST OF WHICH ARE RAINING OUT BY THE TIME THEY CROSS THE I-95
CORRIDOR.
DYNAMIC LIFTING MECHANISMS HAVE WEAKENED CONSIDERABLY OVER THE PAST
24HRS AS A STRONG H30-H20 JET HAS LIFTED E OF THE CAROLINA. MID LVL
OMEGA FIELDS INDICATE A SUBSIDING AIRMASS WHILE UPR LVL DIVERGENCE
IS WEAK OR NEUTRAL. EVEN MID LVL ISENTROPIC LIFT HAS SUBSIDED WITH
ANALYSIS SHOWING WEAK ANTICYCLONIC FLOW IN THRU THE MID LVLS
CONSISTENT WITH THE OMEGA FIELDS. UPSTREAM H100-H70 MOISTURE FIELDS
REMAIN IN THE 70-90PCT RANGE...HI ENOUGH TO KEEP CHC POPS IN FOR THE
COASTAL COUNTIES...DECREASING TO AOB 20PCT FOR THE INTERIOR. GIVEN
THE H100-H85 FLOW AND THE DRY AIR ABV H85...PRECIP PRIMARILY WILL BE
IN THE FORM OF LOW TOPPED SHRAS. GENERALLY LOW RAINFALL POTENTIAL
WITH 24HR QPF AOB 0.10"...LCLY HIGHER AMOUNTS ALONG THE IMMEDIATE
TREASURE COAST DUE TO TRAINING ECHOS...24HR QPF BTWN 0.25-0.50".
NO SIG CHANGE IN AIRMASS WITH THE PERSISTENT NE FLOW...TEMPS NOT
EXPECTED TO DEVIATE MORE THAN A DEG OR TWO FROM SAT. AFTN MAXES IN
THE M/U70S ALONG THE COAST AND U70S/L80S INTERIOR...MIN TEMPS L/M60S
INTERIOR WITH NORMALLY COOLER SPOTS DIPPING BLO 60F N OF I-4...
M60S/L70S ALONG THE COAST. ONE INTERESTING NOTE...SINCE THIS ONSHORE
FLOW PATTERN DVLPD THIS PAST THU...MOST COASTAL OBS SITES HAVE NOT
SEEN DAY-TO-DAY MAX/MIN TEMPS FLUCTUATE BY MORE THAN 10F.
MON-WED...INVERTED TROUGH WHICH FORMS EARLY MONDAY MORNING OFFSHORE
THE FL EAST COAST WILL LIFT OUT RAPIDLY TO THE NE WITH HIGH PRESSURE
AND DRIER AIR BUILDING INTO THE SE STATES AND CENTRAL FL BEHIND IT.
LINGERING CHC FOR SHOWERS ALONG THE EAST COAST WILL SHIFT S/E...WITH
JUST A SMALL LINGERING THREAT AROUND LAKE OKEE/JUPITER TUE INTO TUE
NIGHT. RAIN CHC WILL SPREAD BACK NWD MAINLY ALONG THE COAST WED/WED
EVENING AS ANOTHER WEAK LOW PRES WAVE DEVELOPS OVER THE BAHAMAS AND
LIFTS RAPIDLY NE AS WELL.
MAX TEMPS IN THE 70S..NEAR TO SLIGHTLY ABOVE NORMAL. MON NIGHT LOOKS
TO BE THE COOLEST IN THE SHORT RANGE...IN THE 50S OVER THE INTERIOR
(L50S NORTH OF I-4) WITH A 5-8F SPREAD (M-U50S VS L-M60S) OVER THE
COASTAL COS GIVEN THE SLIGHT ONSHORE COMPONENT THERE. TUE/WED NIGHTS
U50S N/W OF I-4...L60S INLAND/WEST OF I-95...AND M-U60S ALONG THE
IMMEDIATE COAST.
THU-SAT...ZONAL FLOW PATTERN UNDERGOES SIGNIFICANT AMPLIFICATION
LATE NEXT WEEK AS A STRONG TROUGH DIGS INTO THE CTRL CONUS RESULTING
IN DOWNSTREAM MID LEVEL RIDGING ACROSS THE ERN CONUS/FL/WRN ATLC.
CONSEQUENTLY...THE HIGH PRESSURE RIDGE OVER NORTH-CTRL FL THU/EARLY
FRI STRENGTHENS CONSIDERABLY AS IT DRIFTS EAST-NE TO OFFSHORE THE SE
ATLC SEABOARD THIS WEEKEND. THIS PORTENDS DRY/MILD CONDS THU FOLLOWED
INCREASING WARMTH/HUMIDITY FRI-SAT ON THE BACK SIDE OF THE HIGH...
WITH A SMALL CHC FOR SHOWERS SAT AFTERNOON.
&&
.AVIATION...THRU 07/12Z...
SFC WNDS: THRU 06/15Z...N/NE 7-12KTS...OCNL G20KTS CSTL SITES S OF
KMLB. BTWN 06/15Z-06/23Z...E/NE ARND 13-17KTS WITH G20-22KTS. BTWN
06/23Z-0702...BCMG N/NE 6-10KTS.
VSBY/WX/CIGS: THRU 06/15Z...N OF KISM-KDAB PREVAILING CIGS BTWN
FL008-012...S OF KISM-KMLB PREVAILING CIGS BTWN FL060-080 WITH BRIEF
ISOLD MVFR SHRAS. BTWN 06/15Z-06/24Z...PREVAILING CIGS BTWN FL060-
080 ALL SITES...SLGT CHC MVFR -SHRAS E OF KOMN-KISM...CHC MVFR SHRAS
E OF KDAB-KOBE. BTWN 07/00Z-07/04Z...N OF KISM-KTIX CIGS BCMG IFR
BTWN FL006-009 WITH PDS OF LIFR CIGS BLO FL005...S OF KISM-KTIX
PREVAILING CIGS BTWN FL040-060...SLGT CHC MVFR -SHRAS E OF KOMN-
KISM...CHC MVFR -SHRAS E OF KMLB-KOBE.
&&
.MARINE...
TODAY-TONIGHT...HAZARDOUS BOATING CONDITIONS TO CONTINUE...THOUGH
SFC/BNDRY LYR WINDS WILL BEGIN TO DIMINISH BY LATE AFTN AS A HI PRES
RIDGE OVER THE ERN SEABOARD SLOWLY WEAKENS. SEAS WILL BE SLOWER TO
IMPROVE AS THE NE FETCH SPANS THE COAST FROM FL TO THE CAROLINAS...
WHICH WHILE MAINTAIN A MODERATE TO LARGE NE SWELL THRU TONIGHT. EVEN
THIS WILL DAMPEN OUT AS WINDS DIMINISH FROM A MODERATE TO FRESH NE
BREEZE TO A LIGHT TO GENTLE N/NE BREEZE. SEAS 7-9FT NEARSHORE AND 8-
10FT OFFSHORE THRU THE DAY...SUBSIDING TO 5-6FT NEARSHORE AND 6-8FT
OFFSHORE OVERNIGHT. NO CHANGES TO THE CURRENT SCA.
MON-THU...WILL LIKELY SEE BRIEF LULL IN WIND SPEEDS EARLY MONDAY AS
INVERTED TROUGH DEVELOPS OFFSHORE THE EAST COAST. HOWEVER...AS A SFC
LOW FORMS AND LIFTS QUICKLY NE PGRAD WILL TIGHTEN ONCE AGAIN BETWEEN
IT AND THE HIGH BUILDING E/S IN ITS WAKE. HENCE...AFTER A BRIEF 6-9HR
PD WHERE THE SCA WILL LIKELY DROP BACK TO A CAUTIONARY STMT EARLY
MON...WIND SURGE MAY WARRANT A BRIEF (~12HR) SCA LATE MON AFTERNOON
THROUGH PART OR MOST OF THE OVERNIGHT PERIOD. WINDS/SEAS GRADUALLY
WANE FROM TUE-THU AS HIGH PRESSURE DROPS SEWD INTO NORTH-CTRL FL.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 76 62 73 57 / 20 20 20 0
MCO 81 61 78 56 / 10 10 10 0
MLB 79 67 75 61 / 30 30 30 10
VRB 79 69 75 63 / 40 30 40 10
LEE 79 58 76 52 / 10 10 10 0
SFB 79 61 76 55 / 10 10 20 0
ORL 80 62 76 56 / 10 10 10 0
FPR 79 69 78 63 / 40 30 40 10
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...HIGH SURF ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR COASTAL
VOLUSIA COUNTY-INDIAN RIVER-MARTIN-NORTHERN BREVARD COUNTY-
SOUTHERN BREVARD COUNTY-ST. LUCIE.
AM...SMALL CRAFT ADVISORY UNTIL 4 AM EST MONDAY FOR FLAGLER BEACH TO
VOLUSIA-BREVARD COUNTY LINE 0-20 NM-FLAGLER BEACH TO
VOLUSIA-BREVARD COUNTY LINE 20-60 NM-SEBASTIAN INLET TO
JUPITER INLET 0-20 NM-SEBASTIAN INLET TO JUPITER INLET 20-
60 NM-VOLUSIA-BREVARD COUNTY LINE TO SEBASTIAN INLET 0-20
NM-VOLUSIA-BREVARD COUNTY LINE TO SEBASTIAN INLET 20-60 NM.
&&
$$
SHORT TERM/AVIATION...BRAGAW
LONG TERM/IMPACT WX....CRISTALDI
AREA FORECAST DISCUSSION
NWS CARIBOU ME
343 AM EST SUN DEC 6 2015
.SYNOPSIS...
HIGH PRESSURE WILL MOVE OFFSHORE TODAY. A WEAK COLD FRONT WILL
CROSS THE REGION MONDAY. HIGH PRESSURE BUILDS OVER THE AREA MONDAY
NIGHT INTO WEDNESDAY AND MOVES EAST THURSDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
ALL FORECASTING CHALLENGES REMAIN UNDER THE SUBSIDENCE INVERSION
AND THE H925 LAYER. WILL CONTINUE TO FAVOR THE NAM12 IN NORTHERN
ZONES WITH STRATUS AND LOW STRATOCU REFORMING OR THICKENING WITH
SUNRISE AND CONTINUING THROUGH THE DAY AND INTO THE EVENING. THE
SUBSIDENCE INVERSION WILL ERODE STEADILY AS THE UPPER RIDGE MOVES
EAST TODAY AND TONIGHT...BUT WILL REMAIN IN PLACE. WEAK
DOWNSLOPING WILL GENERATE SOME HOLES IN THE STRATOCU TONIGHT...BUT
WILL LEAN TOWARDS CLOUDY SKIES FOR THESE NORTHERN ZONES.
FOR BANGOR AND DOWN EAST...THE LOW STRATOCU IS NOT EXPECTED TO BE
A FACTOR. IN ITS PLACE...FOG AND FREEZING FOG WILL BE THE ISSUES
THIS MORNING. FOLLOWING THE RAP AND HRRR GUIDANCE...FREEZING FOG
WILL BOTH FORM AND ADVECT EASTWARD FROM ITS CURRENT POSITION IN
THE MIDCOAST. THIS FOG IS ANTICIPATED TO AFFECT BANGOR AND DOWN
EAST THROUGH THE MORNING AND POTENTIALLY INTO THE EARLY AFTERNOON.
FOG THIS MORNING WILL ALSO EXTEND UP THE PENOBSCOT RIVER VALLEY
TOWARDS HOULTON. THE FREEZING FOG WILL GENERATE SOME VERY SLICK
ROADS. WILL MAINTAIN THE SPECIAL WEATHER STATEMENT HIGHLIGHTING
THIS RISK THROUGH 8AM AND MAY EXTEND IT. THE SPECIAL WEATHER
STATEMENT IS IN EFFECT FOR THE ENTIRE FORECAST AREA AS MOISTURE
THAT HAS REFROZEN AFTER YESTERDAY`S SNOWMELT IS ALSO CAUSING
HAZARDOUS DRIVING CONDITIONS.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
SFC BNDRY WL BE LOCATED ALONG THE COAST BY THE START OF THE SHORT
TERM. WL TAKE AWHILE FOR SUBSIDENCE INVERSION TO MIX OUT WITH CLDY
CONDS EXPECTED MON MRNG OVR FAR NRN ZONES. FURTHER TO THE SOUTH
EXPECT ANOTHER MOSUNNY DAY WITH TEMPS ABV NORMAL ONCE AGAIN. MAXES
WL BE A FEW DEGREES COOLER THAN SUNDAY`S HIGHS AS H9 CLD ADVECTION
KICKS IN FOLLOWING FROPA. STILL CANNOT RULE OUT A FLURRY BEING WRUNG
OUT IN NW FLOW AS VORT MAX SCOOTS ACRS WITH UPR TROF DRG THE AFTN.
NW FLOW CONTINUES DRG THE OVRNGT HRS WITH PCLDY SKIES EXPECTED ALL
NIGHT ACRS THE NORTH WITH SOME CLRNG ACRS SRN ZONES. WINDS WL BEGIN
TO DROP OFF IN THE NORTH WOODS LATE AS HIPRES BUILDS IN FM THE WEST.
SFC RIDGE AXIS WL BE ACRS CWA DRG THE DAY TUESDAY. H5 TROF CURRENTLY
OVR THE CENTER OF THE NATION WL SWING EAST AND OFF THE MID-ATLANTIC
COAST MON NGT, WITH SFC LOW DVLPNG OFF THE CAROLINA COAST. MODELS
HV TRENDED FURTHER SOUTH AND EAST WITH THIS LOW THUS NOT EXPECTING
ANY IMPACT ON CWA BY TUESDAY OTHER THAN HIGH CLDS AND INCREASE IN
WV HEIGHTS FOR MARINE ZONES.
HIPRES WL SHIFT EAST TUE NIGHT WITH RETURN FLOW BRINGING CLDS BACK
TO THE AREA. MIN TEMPS WL BE SIMILAR TO MON NGT TEMPS WITH CLDY
SKIES AND MINIMAL WARM ADVECTION.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
TEMPS WL MODERATE THROUGHOUT THE LONG TERM AS SRLY FLOW WL
PREDOMINATE THRU THURSDAY. 00Z GFS AND EC HV ANOTHER TROF EXITING
THE MID-ATLANTIC COAST THUR MRNG WITH SFC LOW EJECTING NR THE
VIRGINIA CAPES AT THIS TIME. GFS IS FURTHER NORTH WITH TRACK OF
LOW THAN EC IS WHILE GEM DOES NOT HV ANY INDICATION OF FEATURE
EITHER AT SFC OR ALOFT. THIS LOOKS TO BE THE NEXT POTENTIAL WX-
MAKER TO WATCH THRU THE PD AS RMNDR OF EXTNDD LOOKS QUIET AND
WARM, RELATIVELY SPEAKING.
&&
.AVIATION /07Z SUNDAY THROUGH THURSDAY/...
NEAR TERM: FOG IS EXPECTED TO MOVE ACROSS THE DOWN EAST REGION
THIS MORNING...BRUSHING BGR AND LINGERING IN BHB THROUGH THE
MORNING AND POSSIBLY LONGER. FREEZING FOG IS ALSO AN ISSUE THIS
MORNING AT HUL AND FVE. THE FOG WILL LIFT TO MVFR CIGS THIS
MORNING. ALL SITES NORTH OF HUL WILL HAVE MVFR CIGS MUCH OF SUNDAY
AND INTO THE EVENING.
SHORT TERM: MVFR CIGS EXPECTED OVER NORTHERN TERMINALS ON MONDAY
THEN BECOMING VFR. ANOTHER CHC FOR MVFR RESTRICTIONS ON WED NGT
AND THU.
&&
.MARINE...
NEAR TERM: A FEW GUSTS MAY REACH NEAR 25 KTS TODAY AND THIS
EVENING...BUT DO NOT BELIEVE THE PROBABILITY AND FREQUENCY OF
THESE GUSTS WARRANTS A SMALL CRAFT ADVISORY.
SHORT TERM: SEAS AND WINDS SHOULD REMAIN UNDER SCA LEVELS THROUGH
THE PERIOD.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...CB/DUDA/MCW
SHORT TERM...FARRAR
LONG TERM...FARRAR
AVIATION...CB/DUDA/MCW/FARRAR
MARINE...CB/DUDA/MCW/FARRAR
AREA FORECAST DISCUSSION
NWS GRAY ME
1130 PM EST SAT DEC 5 2015
.SYNOPSIS...
HIGH PRESSURE CENTERED SOUTH OF NEW ENGLAND WILL REMAIN STATIONARY
THROUGH SUNDAY. A WEAK COLD FRONT WILL DROP SOUTH THROUGH THE
REGION SUNDAY NIGHT AND MONDAY FOLLOWED BY ANOTHER AREA OF HIGH
PRESSURE. HIGH PRESSURE WILL HOLD OVER THE REGION TUESDAY THROUGH
WEDNESDAY AS LOW PRESSURE PASSES WELL OFFSHORE. A WARM FRONT WILL
APPROACH FROM THE SOUTHWEST WEDNESDAY NIGHT AND WILL GRADUALLY
LIFT INTO SOUTHERN NEW ENGLAND ON THURSDAY AND INTO NORTHERN NEW
ENGLAND FRIDAY.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
1125 PM UPDATE...JUST MADE SOME MINOR CHANGES TO TEMPERATURES
BASED ON CURRENT OBSERVATIONS AND TRENDS. FREEZING FOG AND BLACK
ICE IS ALREADY STARTING TO SHOW UP ACROSS THE REGION AND A SPECIAL
WEATHER STATEMENT IS CURRENTLY OUT UNTIL 7 AM SUNDAY MORNING.
900 PM UPDATE...ENSEMBLE AND HRRR GUIDANCE IS INDICATING LOW
VISIBILITIES TONIGHT ALONG THE CT RIVER VALLEY AND UP THROUGH THE
MAINE MIDCOAST. ADDED PATCHY FREEZING FOG FOR OVERNIGHT. ALSO,
TEMPERATURES HAVE RADIATED OUT QUITE QUICKLY...ESPECIALLY ACROSS
THE NORTHERN NEW HAMPSHIRE...SO LOWERED FORECAST LOW TEMPERATURES
A BIT TO LINE UP WITH CURRENT OBS AND TRENDS. THE BIGGEST FORECAST
CONCERN WILL BE THE POTENTIAL FOR BLACK ICE ON ROADS TONIGHT WITH
FREEZING FOG DEVELOPING.
515 PM UPDATE...CLEAR SKIES ACROSS MOST OF THE FORECAST AREA
EXCEPT FOR THE FAR NORTH THIS EVENING. SHOULD RADIATE OUT QUITE
EFFICIENTLY AND LOOKING AT THE LATEST OB TRENDS TEMPS HAS COOLED
ABOUT 5 DEGREES IN THE PAST HOUR AFTER SUNSET. WENT A BIT COOLER
FOR OVERNIGHT LOWS TONIGHT AS THIS TREND SHOULD CONTINUE WITH THE
CLEAR SKIES AND LIGHT WINDS.
PREVIOUS DISCUSSION... SFC HIGH BUILDS OVER NEW ENGLAND TONIGHT
WITH AND DESPITE WARMING AIR ALOFT WILL SEE GOOD RAD COOLING
/ALTHOUGH WITHOUT SNOW/ AND TEMPS WILL DROP BACK INTO THE LOW TO
MID 20S IN MANY SPOTS TO AROUND 30 ON THE COAST. ANY EVENING
CLOUDS IN THE MTNS WILL CLEAR LATER TONIGHT...WITH A FEW CIRRUS
MOVING THRU AFTER MIDNIGHT.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...
SFC HIGH HOLDS OVER THE CWA DURING MOST OF THE DAY...BUT WEAK
500MB WAVE PASSING TO OUR N WILL SUPPRESS THE RIDGE ALOFT...AND
ALLOW A WEAK COLD FRONT TO SLIP THRU THE CWA SUN NIGHT.
SUNDAY WILL BE MAINLY AND SUNNY AND MILD...AS SW FLOW INCREASES
AHEAD OF THE FRONT WILL BE ABLE TO BETTER MIX THE WARM AIR ALOFT
THAT SATURDAY AND HIGHS WILL BE A FEW DEGREES WARMER...RANGING
FROM THE MID TO UPPER 40S IN THE MTNS TO THE LOW TO MID 50S...AND
EVEN A FEW UPPER 50S...NEAR THE SW ME COAST AND IN SRN NH.
THE COLD FRONT WILL MOVE THROUGH WITH LITTLE FANFARE SUN
NIGHT...PROBABLY DURING THE LATTER PART OF THE NIGHT...AND WILL
PRODUCE A SCT-BKN MID LVL CLOUDS...BUT NO PRECIP. LOWS WILL
RANGE FROM THE MID 20S N TO LOW 30S S.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
THE MODELS CONTINUE TO SUGGEST THE MEAN LONG WAVE TROUGH REMAINS IN
THE WESTERN US ALLOWING THE LONG WAVE RIDGE AXIS TO MAINTAIN
ITSELF IN THE EAST. HAVE NO REASON TO ARGUE THIS GENERAL PATTERN
WILL CONTINUE THIS OUTLOOK PERIOD.
SO...HIGH PRESSURE WILL DOMINATE OVER OUR AREA THROUGH MIDWEEK. A TEMPORARY
SPLIT FLOW IN THE EAST ALLOWS A SYSTEM TO MOVE OFF THE MID
ATLANTIC COAST AND PASS WELL SOUTH OF NEW ENGLAND TUE AND WED.
THEN LATE IN THE WEEK A SHORT WAVE TROF MOVING THROUGH THE ZONAL
FLOW WILL ALLOW A WARM FRONT TO APPROACH AND EVENTUALLY MOVE NORTH
THROUGH THE AREA LATE THU AND FRIDAY. A WEAK WAVE MAY EVEN DEVELOP
ALONG THE WARM FRONT AS SUGGESTED BY THE EURO. SOME VERY LIGHT
MIXED PCPN MAY OCCUR AHEAD OF THAT SYSTEM BUT WILL BE VERY MINOR.
TEMPERATURES WILL REMAIN ABOVE NORMAL THROUGH THE OUTLOOK PERIOD.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
SHORT TERM...
1125 PM UPDATE...VLIFR CONDITIONS SHOULD CONTINUE THROUGH THE
REMAINDER OF THE NIGHT AT LEB AND RKD DUE TO FREEZING FOG. OTHER
TERMINALS WILL LIKELY SEE AT LEAST A PERIOD OF MVFR AND POSSIBLY
IFR CONDITIONS THROUGH TOMORROW MORNING.
900 PM UPDATE...VLIFR CONDITIONS WILL BE POSSIBLE LATE TONIGHT
INTO TOMORROW MORNING WITH FREEZING FOG DEVELOPING. MOST LIKELY
AREAS WILL BE RKD...LEB...AND AUG...HOWEVER...PATCHY FOG IN OTHER
AREAS MAY ALSO BE POSSIBLE.
PREVIOUS DISCUSSION...VFR THROUGH SUN NIGHT.
LONG TERM...VFR.
&&
.MARINE...
SHORT TERM...NO FLAGS ATTM...BUT WILL SEE SW FLOW APPROACH SCA
LVLS SUN EVENING IN ADVANCE OF A COLD FRONT.
LONG TERM...WAVES APPROACH 5-6 FT TUESDAY NIGHT INTO THU AS A LOW
PRESSURE SYSTEM PASSES WELL SOUTH OF NEW ENGLAND.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...KISTNER
SHORT TERM...
LONG TERM...
AVIATION...
MARINE...
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
417 AM EST SUN DEC 6 2015
.SYNOPSIS...
AREAS OF DENSE FOG WILL PLAGUE PARTS OF THE REGION THIS MORNING.
OTHERWISE...HIGH PRESSURE WILL MAINTAIN PRECIPITATION FREE WEATHER
WITH MODERATING TEMPERATURES.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
WILL LEAVE THE DENSE FOG ADVISORY RUNNING AS IS. LATEST GOES FOG
PRODUCT AND SCATTERED OBSERVATION SITES ARE INDICATING LARGE HOLES
DEVELOPING IN THE FOG BANK. THIS APPEARS TO BE OCCURRING THANKS TO
A VERY DRY LAYER OF AIR JUST ABOVE THE SURFACE THAT IS SINKING AND
PROMOTING A DE-SATURATION OF THE AIR AT GROUND LEVEL. THINKING
THIS TREND WILL CONTINUE...THE FOG ADVISORY MAY BE CANCELLED
EARLY.
SURFACE HIGH PRESSURE WILL SHIFT NORTHEASTWARD TODAY...ALLOWING
FOR LIGHT SOUTHWESTERLY WINDS TO DEVELOP AND THE RESULTING WARM
ADVECTION. OUTSIDE OF ANY AREAS OF LINGERING FOG/LOW CLOUDS...
TEMPERATURES ARE PROJECTED TO BE 5 TO 10 DEGREES ABOVE THE NORMALS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/...
UPPER TROUGH AND ASSOCIATED SURFACE LOW WILL CROSS THE OHIO VALLEY
MONDAY. THE DEEPEST MOISTURE AND STRONGEST LIFT WILL REMAIN JUST
SOUTH OF THE FORECAST AREA...BUT THE NORTHERN EDGE OF THE
PRECIPITATION SHIELD MAY CLIP FAR SOUTHERN COUNTIES MONDAY. HAVE
KEPT WITH THE PREVIOUS IDEA OF SLIGHT CHANCE/LOW CHANCE POPS
ACROSS THE FAR SOUTH DURING THE MORNING AND INTO THE EARLY
AFTERNOON HOURS.
ANOTHER SHORTWAVE...ON THE HEELS OF MONDAY`S SYSTEM...WILL CROSS
LATE ON TUESDAY. THIS TIME THE DEEPEST MOISTURE AND STRONGEST
LIFT WILL BE NORTH OF THE REGION. AGREE WITH THE PREVIOUS DRY
FORECAST AND THE PLACEMENT OF CLOUD COVER. TEMPERATURES BOTH DAYS
WERE HELD NEAR CLIMATOLOGICAL NORMALS.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
UPPER LEVEL PATTERN WILL CONTINUE TO SUPPORT FAST MOVING
SHORTWAVES UNTIL LATE IN THE WEEK WHEN AMPLIFICATION OF THE
TROUGH OVER THE WESTERN CONUS SUPPORTS RIDGING IN THE EAST. THERE
ARE SOME STRENGTH AND TIMING DIFFERENCES EVIDENT BETWEEN THE
GFS...ECMWF...AND OTHER MODEL GUIDANCE FOR A LATE WEAK LOW
PRESSURE SYSTEM.
UPPER RIDGING WILL SUPPORT MODERATING TEMPERATURES TO WELL ABOVE
SEASONAL AVERAGES BY SATURDAY.
&&
.AVIATION /09Z SUNDAY THROUGH THURSDAY/...
THERE WILL BE A BRIEF PERIOD OF VFR CONDITIONS BEFORE LIGHT
WIND...RESIDUAL MOISTURE AND COOLING LEAD THE AIR MASS TO REACH
SATURATION AGAIN...ESPECIALLY IN RIVER VALLEYS. 00Z TAFS INCLUDE A
MIX OF A PERSISTENCE FORECAST FROM OBSERVATIONS OVER THE LAST 24
HOURS AND THE 20Z HRRR MODEL...WHICH HAD THE BEST SPATIAL COVERAGE
OF FOG COMPARED TO CURRENT SATELLITE IMAGERY. FOG IS CURRENTLY
PATCHY ACROSS EASTERN OHIO AND NORTHWESTERN PENNSYLVANIA...BUT
THIS FOG IS EXPECTED TO EXPAND SOUTH AND EAST IN COVERAGE THROUGH
THE NEXT SEVERAL HOURS. FOG IS LIKELY TO PERSIST INTO SUNDAY
MORNING...IF NOT EARLY AFTERNOON. DISSIPATION TO VFR CONDITIONS
WILL BE AIDED BY SOUTHWEST WINDS DEVELOPING ON SUNDAY...COMPARED
TO THE NEAR CALM CONDITIONS WITH HIGH PRESSURE CURRENTLY ACROSS
THE REGION.
.OUTLOOK...SUNDAY NIGHT THROUGH THURSDAY/...
VFR CONDITIONS ARE EXPECTED GENERALLY THROUGH THE PERIOD. LIGHT
RAIN MAY IMPACT KZZV/KMGW ON MONDAY AS AN UPPER-LEVEL DISTURBANCE
CROSSES THE REGION.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...DENSE FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR OHZ039>041-
048>050-057-058-068.
PA...DENSE FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR PAZ007>009-
013>016-020>023.
WV...DENSE FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR WVZ001.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS PITTSBURGH PA
202 AM EST SUN DEC 6 2015
.SYNOPSIS...
AREAS OF DENSE FOG WILL PLAGUE PARTS OF THE REGION THROUGH THE
MORNING. OTHERWISE...HIGH PRESSURE WILL MAINTAIN PRECIPITATION
FREE WEATHER WITH MODERATING TEMPERATURES.
&&
.NEAR TERM /THROUGH TODAY/...
WILL BE EXTENDING THE FOG ADVISORY TO COVER ALLEGHENY COUNTY IN
SOUTHWEST PA. APPEARS TO BE SOME SLOW IMPROVEMENT TO THE FAR
WEST...PERHAPS DUE TO A WEAKENING OF THE LOW LEVEL INVERSION. WILL
CONTINUE TO MONITOR.
PREVIOUS DISCUSSION...
OVERNIGHT FORECAST WILL REQUIRE A CLOSE WATCH ON THE FOG AND
STRATUS CLOUDS. THE CURRENT DENSE FOG ADVISORY LOOKS WELL PLOTTED
BUT WILL CONTINUE TO WATCH VISIBILITIES THROUGH THE NIGHT AND
EXPAND IF NEEDED. CURRENT HIRES MODEL DATA DOES SHOW SOME
EXPANSION TO THE SOUTH AND EAST OF THE STRATUS DECK...SO HAVE
MODIFIED THE CLOUDS TO COVER FOR THIS.
SURFACE HIGH PRESSURE WILL SHIFT NORTHEASTWARD TODAY...ALLOWING
FOR LIGHT SOUTHWESTERLY WINDS TO DEVELOP AND THE RESULTING WARM
ADVECTION. OUTSIDE OF ANY AREAS OF LINGERING FOG/LOW CLOUDS...
TEMPERATURES ARE PROJECTED TO BE 5 TO 10 DEGREES ABOVE THE NORMALS.
&&
.SHORT TERM /TONIGHT THROUGH TUESDAY/...
UPPER TROUGH AND ASSOCIATED SURFACE LOW WILL CROSS THE OHIO VALLEY
MONDAY. THE DEEPEST MOISTURE AND STRONGEST LIFT WILL REMAIN JUST
SOUTH OF THE FORECAST AREA...BUT THE NORTHERN EDGE OF THE
PRECIPITATION SHIELD MAY CLIP FAR SOUTHERN COUNTIES MONDAY. HAVE
KEPT WITH THE PREVIOUS IDEA OF SLIGHT CHANCE/LOW CHANCE POPS
ACROSS THE FAR SOUTH DURING THE MORNING AND INTO THE EARLY
AFTERNOON HOURS.
ANOTHER SHORTWAVE...ON THE HEELS OF MONDAY`S SYSTEM...WILL CROSS
LATE ON TUESDAY. THIS TIME THE DEEPEST MOISTURE AND STRONGEST
LIFT WILL BE NORTH OF THE REGION. AGREE WITH THE PREVIOUS DRY
FORECAST AND THE PLACEMENT OF CLOUD COVER. TEMPERATURES BOTH DAYS
WERE HELD NEAR CLIMATOLOGICAL NORMALS.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
UPPER LEVEL PATTERN WILL CONTINUE TO SUPPORT FAST MOVING
SHORTWAVES UNTIL LATE IN THE WEEK WHEN AMPLIFICATION OF THE
TROUGH OVER THE WESTERN CONUS SUPPORTS RIDGING IN THE EAST. THERE
ARE SOME STRENGTH AND TIMING DIFFERENCES EVIDENT BETWEEN THE
GFS...ECMWF...AND OTHER MODEL GUIDANCE FOR A LATE WEAK LOW
PRESSURE SYSTEM.
UPPER RIDGING WILL SUPPORT MODERATING TEMPERATURES TO WELL ABOVE
SEASONAL AVERAGES BY SATURDAY.
&&
.AVIATION /07Z SUNDAY THROUGH THURSDAY/...
THERE WILL BE A BRIEF PERIOD OF VFR CONDITIONS BEFORE LIGHT
WIND...RESIDUAL MOISTURE AND COOLING LEAD THE AIR MASS TO REACH
SATURATION AGAIN...ESPECIALLY IN RIVER VALLEYS. 00Z TAFS INCLUDE A
MIX OF A PERSISTENCE FORECAST FROM OBSERVATIONS OVER THE LAST 24
HOURS AND THE 20Z HRRR MODEL...WHICH HAD THE BEST SPATIAL COVERAGE
OF FOG COMPARED TO CURRENT SATELLITE IMAGERY. FOG IS CURRENTLY
PATCHY ACROSS EASTERN OHIO AND NORTHWESTERN PENNSYLVANIA...BUT
THIS FOG IS EXPECTED TO EXPAND SOUTH AND EAST IN COVERAGE THROUGH
THE NEXT SEVERAL HOURS. FOG IS LIKELY TO PERSIST INTO SUNDAY
MORNING...IF NOT EARLY AFTERNOON. DISSIPATION TO VFR CONDITIONS
WILL BE AIDED BY SOUTHWEST WINDS DEVELOPING ON SUNDAY...COMPARED
TO THE NEAR CALM CONDITIONS WITH HIGH PRESSURE CURRENTLY ACROSS
THE REGION.
.OUTLOOK...SUNDAY NIGHT THROUGH THURSDAY/...
VFR CONDITIONS ARE EXPECTED GENERALLY THROUGH THE PERIOD. LIGHT
RAIN MAY IMPACT KZZV/KMGW ON MONDAY AS AN UPPER-LEVEL DISTURBANCE
CROSSES THE REGION.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...DENSE FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR OHZ039>041-
048>050-057-058-068.
PA...DENSE FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR PAZ007>009-
013>016-020>023.
WV...DENSE FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR WVZ001.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS PITTSBURGH PA
1237 AM EST SUN DEC 6 2015
.SYNOPSIS...
AREAS OF DENSE FOG WILL PLAGUE PARTS OF THE REGION THROUGH THE
MORNING. OTHERWISE...HIGH PRESSURE WILL MAINTAIN PRECIPITATION
FREE WEATHER WITH MODERATING TEMPERATURES.
&&
.NEAR TERM /THROUGH TODAY/...
OVERNIGHT FORECAST WILL REQUIRE A CLOSE WATCH ON THE FOG AND
STRATUS CLOUDS. THE CURRENT DENSE FOG ADVISORY LOOKS WELL PLOTTED
BUT WILL CONTINUE TO WATCH VISIBILITIES THROUGH THE NIGHT AND
EXPAND IF NEEDED. CURRENT HIRES MODEL DATA DOES SHOW SOME
EXPANSION TO THE SOUTH AND EAST OF THE STRATUS DECK...SO HAVE
MODIFIED THE CLOUDS TO COVER FOR THIS.
SURFACE HIGH PRESSURE WILL SHIFT NORTHEASTWARD TODAY...ALLOWING
FOR LIGHT SOUTHWESTERLY WINDS TO DEVELOP AND THE RESULTING WARM
ADVECTION. OUTSIDE OF ANY AREAS OF LINGERING FOG/LOW CLOUDS...
TEMPERATURES ARE PROJECTED TO BE 5 TO 10 DEGREES ABOVE THE NORMALS.
&&
.SHORT TERM /TONIGHT THROUGH TUESDAY/...
UPPER TROUGH AND ASSOCIATED SURFACE LOW WILL CROSS THE OHIO VALLEY
MONDAY. THE DEEPEST MOISTURE AND STRONGEST LIFT WILL REMAIN JUST
SOUTH OF THE FORECAST AREA...BUT THE NORTHERN EDGE OF THE
PRECIPITATION SHIELD MAY CLIP FAR SOUTHERN COUNTIES MONDAY. HAVE
KEPT WITH THE PREVIOUS IDEA OF SLIGHT CHANCE/LOW CHANCE POPS
ACROSS THE FAR SOUTH DURING THE MORNING AND INTO THE EARLY
AFTERNOON HOURS.
ANOTHER SHORTWAVE...ON THE HEELS OF MONDAY`S SYSTEM...WILL CROSS
LATE ON TUESDAY. THIS TIME THE DEEPEST MOISTURE AND STRONGEST
LIFT WILL BE NORTH OF THE REGION. AGREE WITH THE PREVIOUS DRY
FORECAST AND THE PLACEMENT OF CLOUD COVER. TEMPERATURES BOTH DAYS
WERE HELD NEAR CLIMATOLOGICAL NORMALS.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
UPPER LEVEL PATTERN WILL CONTINUE TO SUPPORT FAST MOVING
SHORTWAVES UNTIL LATE IN THE WEEK WHEN AMPLIFICATION OF THE
TROUGH OVER THE WESTERN CONUS SUPPORTS RIDGING IN THE EAST. THERE
ARE SOME STRENGTH AND TIMING DIFFERENCES EVIDENT BETWEEN THE
GFS...ECMWF...AND OTHER MODEL GUIDANCE FOR A LATE WEAK LOW
PRESSURE SYSTEM.
UPPER RIDGING WILL SUPPORT MODERATING TEMPERATURES TO WELL ABOVE
SEASONAL AVERAGES BY SATURDAY.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
THERE WILL BE A BRIEF PERIOD OF VFR CONDITIONS BEFORE LIGHT
WIND...RESIDUAL MOISTURE AND COOLING LEAD THE AIR MASS TO REACH
SATURATION AGAIN...ESPECIALLY IN RIVER VALLEYS. 00Z TAFS INCLUDE A
MIX OF A PERSISTENCE FORECAST FROM OBSERVATIONS OVER THE LAST 24
HOURS AND THE 20Z HRRR MODEL...WHICH HAD THE BEST SPATIAL COVERAGE
OF FOG COMPARED TO CURRENT SATELLITE IMAGERY. FOG IS CURRENTLY
PATCHY ACROSS EASTERN OHIO AND NORTHWESTERN PENNSYLVANIA...BUT
THIS FOG IS EXPECTED TO EXPAND SOUTH AND EAST IN COVERAGE THROUGH
THE NEXT SEVERAL HOURS. FOG IS LIKELY TO PERSIST INTO SUNDAY
MORNING...IF NOT EARLY AFTERNOON. DISSIPATION TO VFR CONDITIONS
WILL BE AIDED BY SOUTHWEST WINDS DEVELOPING ON SUNDAY...COMPARED
TO THE NEAR CALM CONDITIONS WITH HIGH PRESSURE CURRENTLY ACROSS
THE REGION.
.OUTLOOK...SUNDAY NIGHT THROUGH THURSDAY/...
VFR CONDITIONS ARE EXPECTED GENERALLY THROUGH THE PERIOD. LIGHT
RAIN MAY IMPACT KZZV/KMGW ON MONDAY AS AN UPPER-LEVEL DISTURBANCE
CROSSES THE REGION.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...DENSE FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR OHZ039>041-
048>050-057-058-068.
PA...DENSE FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR PAZ007>009-
013>016-020-022-023.
WV...DENSE FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR WVZ001.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
436 AM EST SUN DEC 6 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 436 AM EST SUN DEC 6 2015
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A SPLIT FLOW ACRS
NAMERICA DOWNWIND OF A DEEPER TROF OFF THE W COAST WITH A NEARLY
ZONAL NRN BRANCH FLOW OVER SRN CANADA AND THE SRN BRANCH FLOW IN THE
CONUS. A SHRTWV IN THE NRN BRANCH FLOW IS OVER NRN MANITOBA EARLY
THIS MRNG...WITH ASSOCIATED SFC LO NEAR THE SW EDGE OF HUDSON BAY. A
RATHER WEAK ATTENDANT SFC COLD FNT EXTENDS SWWD INTO MN. THE AIRMASS
BEHIND THE FNT IS PACIFIC IN ORIGIN...WITH 00Z H85 TEMPS NO LOWER
THAN 0-2C FM LK WINNIPEG INTO THE NRN PLAINS. THE TRAILING AIRMASS
IS QUITE DRY PER THE 00Z BISMARCK RAOB...WHERE THE PWAT WAS ONLY
0.25 INCH AT 00Z. THE PASSAGE OF STRONGER DYNAMIC FORCING IN CANADA
CLOSER TO NRN SHRTWV AND VERY DRY PREFRONTAL AIRMASS SHOWN ON THE
00Z GRB RAOB WITH DEEPER MSTR INFLOW TO THE N INTERRUPTED BY STRONG
SRN BRANCH DISTURBANCE MOVING INTO THE MID MS RIVER VALLEY IS
PREVENTING MUCH IF ANY PCPN AHEAD OF THIS APRCHG COLD FNT.
HOWEVER...THERE IS A GOOD OF LO CLD AHEAD OF THE FNT...AND THIS LO
CLD IS MOVING INTO THE WRN CWA. COMBINATION OF STEADY SW WINDS UNDER
SHARPER PRES GRADIENT BTWN THE APRCHG FNT AND HI PRES IN THE MID
ATLANTIC AND A GOOD DEAL OF HI CLDS OVER THE ENTIRE CWA/LO CLDS
MOVING INTO THE W IS LEADING TO WELL ABOVE NORMAL TEMPS OVER UPR
MI...WITH EARLY MRNG TEMPS GENERALLY 35 TO 40.
MAIN FCST CONCERNS IN THE SHORT TERM FOCUS ON SLIM PCPN CHCS/CLD
TRENDS ASSOCIATED WITH APRCHG COLD FNT. FOCUS FOR TNGT WL SHIFT TO
TEMPS AS DRIER AIRMASS BEHIND THE FNT PUSHES INTO THE UPR LKS.
TODAY...NRN BRANCH SHRTWV/SFC LO PRES ARE PROGGED TO CONTINUE TO THE
E...WITH ATTENDANT COLD FNT CROSSING UPR MI AND REACHING NEWBERRY
LATE IN THE AFTN. SINCE THE SHARPER UPR FORCING WL REMAIN TO THE N
AND S OF UPR MI...FCST SDNGS SHOW GENERALLY DRY MID LVLS BTWN HI
CLDS AND SHALLOW HIER RH ASSOCIATED WITH THE MORE ABUNDANT LO
CLDS...THERE HAVE NO PCPN REPORTS UPSTREAM...AND JUST A FEW OF EVEN
THE HIER RES MODELS GENERATE ANY PCPN OVER THE CWA...OPTED TO REMOVE
POPS EXCEPT FOR SOME SCHC POPS OVER LK SUP. DRIER MID LVL AIR IS
FCST TO FOLLOW DURING THE AFTN...BUT LO CLDS ARE LIKELY TO LINGER A
BIT LONGER WITH LO SUN ANGLE/LINGERING LLVL MSTR. SINCE HIER RES
MODEL FCST H95-9 RH HAS A PRETTY GOOD HANDLE ON THE LO CLD COVERAGE
EARLY THIS MRNG... UTILIZED THIS FCST FIELD TO HANDLE CLD TRENDS IN
THE GRIDS. THESE MODELS SHOW LO CLDS CLRG THE NW HALF OF THE CWA BY
00Z MON WITH ARRIVAL OF DRIER AIRMASS IN THE NRN PLAINS. AFTER THESE
LO CLDS ARRIVE BY 15Z OVER THE SE CWA...WL RETAIN THAT SKY COVER
OVER THE SE HALF THRU 00Z.
TNGT...LINGERING LO CLDS OVER THE SE CWA WL CLR THIS EVNG WITH
ARRIVAL OF THE DRIER AIR/PWAT AOB 0.25 INCH/SFC HI PRES RDG. WITH
LGT WINDS/MOCLR SKIES...TENDED TOWARD THE LO END OF GUIDANCE FOR MIN
TEMPS EVEN THOUGH SOME HI CLDS MAY ARRIVE LATER. RETAINED MENTION OF
SOME PATCHY GROUND FOG AS WELL WITH THE EXPECTED FVRBL RADIATIONAL
COOLING CONDITIONS.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 258 AM EST SUN DEC 6 2015
MON LOOKS TO BE THE QUIETEST DAY AS AN UPPER RIDGE PASSES OVERHEAD.
SHOULD SEE HIGHS IN THE 40S.
FORECAST FOR MON NIGHT THROUGH NEXT WEEKEND IS UNCERTAIN AS SEVERAL
SHORTWAVES MOVE THROUGH OR NEAR THE REGION...LEADING TO MAINLY LIGHT
PRECIP AT TIMES. MON NIGHT INTO TUE MORNING COULD SEE SOME VERY
MINIMAL RAIN AND POSSIBLY SOME SNOW...BUT DEFINITELY LOW CHANCES.
TUE NIGHT INTO WED MORNING COULD SEE SOME RAIN/SNOW AS A STRONGER
SHORTWAVE MOVES THROUGH THE REGION...BUT THAT WILL DEPEND ON
TRACK/STRENGTH DETAILS. THE ECMWF IS MOSTLY DRY DURING THE PERIOD
(EXCEPT FOR SOME VERY LIGHT LAKE ENHANCEMENT OVER THE E)...BUT THE
GFS AND NAM SHOW SOME GREATER PRECIP AMOUNTS (BUT STILL FAIRLY
MINOR). MODELS SHOW POTENTIAL FOR A STRONGER SYSTEM POSSIBLY LATE
THIS WEEK AND MAYBE ANOTHER STRONGER SYSTEM OVER THE WEEKEND...BUT
CONFIDENCE IS QUITE LOW. MODELS HINT AT COLDER AIR MOVING IN WITH
AND BEHIND THOSE STRONGER SYSTEMS...IF THEY MATERIALIZE.
OTHERWISE...TEMPS WILL CONTINUE TO BE WELL ABOVE NORMAL.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1222 AM EST SUN DEC 6 2015
THE MAIN FOCUS IS ON AN APPROACHING COLD FRONT THAT MAY BRING AN
ISOLATED SHOWER TO THE NORTHERN HALF OF UPPER MICHIGAN LATE TONIGHT
INTO SUN MORNING. AHEAD OF THE FRONT...THE MODELS SUGGEST IFR CIGS
WILL DEVELOP UNDER THE LOW LEVEL SOUTHWESTERLY FLOW TONIGHT.
THIS IS CONSISTENT WITH UPSTREAM OBS OVER MN WITH LOWER END MVFR
CIGS AND SOME JUST INTO THE IFR CATEGORY. THE BEST CHANCE FOR THE
LOWEST CIGS IS AT IWD AND CMX SINCE THE SW TO WSW WIND WILL BE OF A
MORE DOWNSLOPE DIRECTION AT SAW. EXPECT THAT LEVEL LEVEL DRYING SUN
AFTERNOON WILL BRING A RETURN TO VFR CONDITIONS.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 258 AM EST SUN DEC 6 2015
EXPECT SW WINDS TO DIMINISH TODAY AS THE PRESSURE GRADIENT
WEAKENS...REMAINING LESS THAN 25 KTS THROUGH THE REST OF THE
FORECAST PERIOD.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...TITUS
AVIATION...JLB
MARINE...TITUS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
316 AM EST SUN DEC 6 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 313 AM EST SUN DEC 6 2015
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A SPLIT FLOW ACRS
NAMERICA DOWNWIND OF A DEEPER TROF OFF THE W COAST WITH A NEARLY
ZONAL NRN BRANCH FLOW OVER SRN CANADA AND THE SRN BRANCH FLOW IN THE
CONUS. A SHRTWV IN THE NRN BRANCH FLOW IS OVER NRN MANITOBA EARLY
THIS MRNG...WITH ASSOCIATED SFC LO NEAR THE SW EDGE OF HUDSON BAY. A
RATHER WEAK ATTENDANT SFC COLD FNT EXTENDS SWWD INTO MN. THE AIRMASS
BEHIND THE FNT IS PACIFIC IN ORIGIN...WITH 00Z H85 TEMPS NO LOWER
THAN 0-2C FM LK WINNIPEG INTO THE NRN PLAINS. THE TRAILING AIRMASS
IS QUITE DRY PER THE 00Z BISMARCK RAOB...WHERE THE PWAT WAS ONLY
0.25 INCH AT 00Z. THE PASSAGE OF STRONGER DYNAMIC FORCING IN CANADA
CLOSER TO NRN SHRTWV AND VERY DRY PREFRONTAL AIRMASS SHOWN ON THE
00Z GRB RAOB WITH DEEPER MSTR INFLOW TO THE N INTERRUPTED BY STRONG
SRN BRANCH DISTURBANCE MOVING INTO THE MID MS RIVER VALLEY IS
PREVENTING MUCH IF ANY PCPN AHEAD OF THIS APRCHG COLD FNT.
HOWEVER...THERE IS A GOOD OF LO CLD AHEAD OF THE FNT...AND THIS LO
CLD IS MOVING INTO THE WRN CWA. COMBINATION OF STEADY SW WINDS UNDER
SHARPER PRES GRADIENT BTWN THE APRCHG FNT AND HI PRES IN THE MID
ATLANTIC AND A GOOD DEAL OF HI CLDS OVER THE ENTIRE CWA/LO CLDS
MOVING INTO THE W IS LEADING TO WELL ABOVE NORMAL TEMPS OVER UPR
MI...WITH EARLY MRNG TEMPS GENERALLY 35 TO 40.
MAIN FCST CONCERNS IN THE SHORT TERM FOCUS ON SLIM PCPN CHCS/CLD
TRENDS ASSOCIATED WITH APRCHG COLD FNT. FOCUS FOR TNGT WL SHIFT TO
TEMPS AS DRIER AIRMASS BEHIND THE FNT PUSHES INTO THE UPR LKS.
TODAY...NRN BRANCH SHRTWV/SFC LO PRES ARE PROGGED TO CONTINUE TO THE
E...WITH ATTENDANT COLD FNT CROSSING UPR MI AND REACHING NEWBERRY
LATE IN THE AFTN. SINCE THE SHARPER UPR FORCING WL REMAIN TO THE N
AND S OF UPR MI...FCST SDNGS SHOW GENERALLY DRY MID LVLS BTWN HI
CLDS AND SHALLOW HIER RH ASSOCIATED WITH THE MORE ABUNDANT LO
CLDS...THERE HAVE NO PCPN REPORTS UPSTREAM...AND JUST A FEW OF EVEN
THE HIER RES MODELS GENERATE ANY PCPN OVER THE CWA...OPTED TO REMOVE
POPS EXCEPT FOR SOME SCHC POPS OVER LK SUP. DID HOWEVER RETAIN A
MENTION OF SOME DRIZZLE/FRZG DRIZZLE AND PATCHY FOG THIS MRNG OVER
MAINLY THE HIER TERRAIN OF THE INTERIOR W WHERE LLVL SATURATION IS
MORE LIKELY IN LLVL SW FLOW. EVEN IF THERE IS SOME FRZG DRIZZLE...
ANY ICING WL BE NEGLIGIBLE. DRIER MID LVL AIR IS FCST TO FOLLOW
DURING THE AFTN...BUT LO CLDS ARE LIKELY TO LINGER A BIT LONGER WITH
LO SUN ANGLE. SINCE HIER RES MODEL FCST H95-9 RH HAS A PRETTY GOOD
HANDLE ON THE LO CLD COVERAGE EARLY THIS MRNG...UTILIZED THIS FCST
FIELD TO HANDLE CLD TRENDS IN THE GRIDS. THESE MODELS SHOW LO CLDS
CLRG THE NW HALF OF THE CWA BY 00Z MON WITH ARRIVAL OF DRIER AIRMASS
IN THE NRN PLAINS. AFTER THESE LO CLDS ARRIVE BY 15Z OVER THE SE
CWA...WL RETAIN THAT SKY COVER OVER THE SE HALF THRU 00Z.
TNGT...LINGERING LO CLDS OVER THE SE CWA WL CLR THIS EVNG WITH
ARRIVAL OF THE DRIER AIR/PWAT AOB 0.25 INCH/SFC HI PRES RDG. WITH
LGT WINDS/MOCLR SKIES...TENDED TOWARD THE LO END OF GUIDANCE FOR MIN
TEMPS EVEN THOUGH SOME HI CLDS MAY ARRIVE LATER. RETAINED MENTION OF
SOME PATCHY GROUND FOG AS WELL WITH THE EXPECTED FVRBL RADIATIONAL
COOLING CONDITIONS.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 258 AM EST SUN DEC 6 2015
MON LOOKS TO BE THE QUIETEST DAY AS AN UPPER RIDGE PASSES OVERHEAD.
SHOULD SEE HIGHS IN THE 40S.
FORECAST FOR MON NIGHT THROUGH NEXT WEEKEND IS UNCERTAIN AS SEVERAL
SHORTWAVES MOVE THROUGH OR NEAR THE REGION...LEADING TO MAINLY LIGHT
PRECIP AT TIMES. MON NIGHT INTO TUE MORNING COULD SEE SOME VERY
MINIMAL RAIN AND POSSIBLY SOME SNOW...BUT DEFINITELY LOW CHANCES.
TUE NIGHT INTO WED MORNING COULD SEE SOME RAIN/SNOW AS A STRONGER
SHORTWAVE MOVES THROUGH THE REGION...BUT THAT WILL DEPEND ON
TRACK/STRENGTH DETAILS. THE ECMWF IS MOSTLY DRY DURING THE PERIOD
(EXCEPT FOR SOME VERY LIGHT LAKE ENHANCEMENT OVER THE E)...BUT THE
GFS AND NAM SHOW SOME GREATER PRECIP AMOUNTS (BUT STILL FAIRLY
MINOR). MODELS SHOW POTENTIAL FOR A STRONGER SYSTEM POSSIBLY LATE
THIS WEEK AND MAYBE ANOTHER STRONGER SYSTEM OVER THE WEEKEND...BUT
CONFIDENCE IS QUITE LOW. MODELS HINT AT COLDER AIR MOVING IN WITH
AND BEHIND THOSE STRONGER SYSTEMS...IF THEY MATERIALIZE.
OTHERWISE...TEMPS WILL CONTINUE TO BE WELL ABOVE NORMAL.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1222 AM EST SUN DEC 6 2015
THE MAIN FOCUS IS ON AN APPROACHING COLD FRONT THAT MAY BRING AN
ISOLATED SHOWER TO THE NORTHERN HALF OF UPPER MICHIGAN LATE TONIGHT
INTO SUN MORNING. AHEAD OF THE FRONT...THE MODELS SUGGEST IFR CIGS
WILL DEVELOP UNDER THE LOW LEVEL SOUTHWESTERLY FLOW TONIGHT.
THIS IS CONSISTENT WITH UPSTREAM OBS OVER MN WITH LOWER END MVFR
CIGS AND SOME JUST INTO THE IFR CATEGORY. THE BEST CHANCE FOR THE
LOWEST CIGS IS AT IWD AND CMX SINCE THE SW TO WSW WIND WILL BE OF A
MORE DOWNSLOPE DIRECTION AT SAW. EXPECT THAT LEVEL LEVEL DRYING SUN
AFTERNOON WILL BRING A RETURN TO VFR CONDITIONS.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 258 AM EST SUN DEC 6 2015
EXPECT SW WINDS TO DIMINISH TODAY AS THE PRESSURE GRADIENT
WEAKENS...REMAINING LESS THAN 25 KTS THROUGH THE REST OF THE
FORECAST PERIOD.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...TITUS
AVIATION...JLB
MARINE...TITUS
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1209 AM EST SUN DEC 6 2015
.AVIATION...
THE 00Z DTX SOUNDING SHOWCASED A CLASSIC DENSE FOG PROFILE WITH A
SHALLOW MOIST LAYER CAPPED BY A VERY DEEP INVERSION /BASED AT 300
FT/. THE LAYER ABOVE THIS INVERSION IS ALSO EXTREMELY DRY...MAKING
COOLING ATOP THE MOIST LAYER EVEN MORE EFFICIENT. WHILE DENSE FOG
HAS BECOME LOCKED IN ALONG AND SOUTH OF THE IRISH HILLS...THERE IS A
GOOD DEAL OF UNCERTAINTY AS TO THE EXTENT OF LOW CLOUDS/FOG NORTH OF
THE IRISH HILLS /FNT AND MBS TERMINALS/. COMPLICATING MATTERS DURING
THE MORNING WILL BE THE THICK CANOPY OF HIGH CLOUDS ROLLING
IN...MAKING IT DIFFICULT TO MONITOR THE FOG/STRATUS PROGRESSION ON
SATELLITE. THE SOUTHERLY FLOW HAS AN UPSLOPE COMPONENT WHICH SHOULD
KEEP DENSE FOG LOCKED IN FROM PTK SOUTH ACROSS METRO DETROIT THROUGH
THE MORNING. NORTH OF THE IRISH HILLS...THIS FLOW HAS A DOWNSLOPE
COMPONENT. THIS FLOW IS ALSO STRONGER FROM FNT NORTHWARD. RECENT
OBSERVATIONS ARE SUGGESTING THE FOG/LOW CLOUDS ARE STRUGGLING TO
LIFT NORTHWARD GIVEN THESE FACTORS. THIS WILL SUPPORT EASING UP ON
THE CEILING/VISIBILITIES AT FNT AND MBS FROM THE PREVIOUS FORECAST.
FOR DTW...CONFIDENCE IS GROWING THAT DENSE FOG WILL REMAIN LOCKED IN
WELL INTO THE MORNING. LIKE YESTERDAY...DAYTIME HEATING WILL OFFER
SOME IMPROVEMENT TO VISIBILITIES WITH THE CLOUD BASE LIFTING
SLIGHTLY /16-18Z TIME FRAME/. LOW LEVEL WINDS ARE FORECAST TO VEER
SLIGHTLY MORE SW SUN EVENING. THIS WILL LEAD TO SOME LOSS OF A
BETTER UPSLOPE COMPONENT. THIS AND SOME WEAKENING OF THE LOW LEVEL
INVERSION MAY BE ENOUGH TO ERODE THE LINGERING LIFR STRATUS DECK
LATE IN THE DAY.
//DTW THRESHOLD PROBABILITIES...
* HIGH IN VSBY/CIGS BELOW 1/2SM AND/OR 200 FT THIS MORNING. LOW
EARLY THIS AFTERNOON.
* HIGH IN CEILINGS BELOW 5000 FT SUNDAY MORNING AND AFTERNOON.
&&
.PREV DISCUSSION...ISSUED 749 PM EST SAT DEC 5 2015
UPDATE...
STEADY SATURATION OF THE NOCTURNALLY COOLING AND SUFFICIENTLY MOIST
SHALLOW SUB-500 FT LAYER AGAIN LEADING TO AN AGGRESSIVE EXPANSION IN
STRATUS/FOG POST-SUNSET. LATEST HRRR GUIDANCE CASTS LITTLE DOUBT
THAT CONTINUED CONDENSATION WITHIN THE NEAR SURFACE LAYER WILL MOVE
THIS PROCESS TOWARD A DENSE FOG SITUATION AS THE NIGHT WEARS ON. IN
LIGHT OF TRENDS IN OBSERVATIONAL/SATELLITE DATA THUS FAR...AND
EXPECTATIONS MOVING FORWARD...WILL GO AHEAD WITH A DENSE FOG
ADVISORY TO CAPTURE THE ENTIRE MORNING PERIOD. SOME UNCERTAINTY
YET AS POTENTIAL COVERAGE OF DENSE FOG ACROSS THE TRI-
CITIES...THIS QUESTION PRECLUDING A PROACTIVE HEADLINE ISSUANCE AT
THIS POINT ALONG THAT CORRIDOR.
PREV DISCUSSION...ISSUED 323 PM EST SAT DEC 5 2015
DISCUSSION...
SIGNIFICANT RIDGING ALOFT HAS SUPPORTED A VERY WARM LOWER AND MID
TROPOSPHERIC COLUMN ACROSS THE UPPER MIDWEST AND GREAT LAKES
REGIONS. THE CONSEQUENCE OF THIS MASS CONFIGURATION IS THE
PRODUCTION OF A VERY SHALLOW COOL LAYER AT THE SURFACE THAT CANNOT
MIX WITH THE SLIGHTLY ELEVATED WARM LATER DUE TO THE EXTREMELY
STABLE TRANSITION LAYER. THE MOISTURE CONTENT BELOW THIS STRONG
INVERSION IS REMAINING FAIRLY CONSTANT...SO IT SIMPLY GOES THROUGH A
CONDENSATION CYCLE DURING THE NOCTURNAL HOURS AND EVAPORATION DURING
THE DIURNAL WINDOW. GIVEN THE RATHER STEADY-STATE SURFACE RIDGING
AND LACK OF AIRMASS REPLACEMENT NEAR THE GROUND...THIS CYCLE WILL
CONTINUE CERTAINLY THROUGH TONIGHT AND INDICATIONS ARE AN ADDITIONAL
TWO MORE DAYS BEFORE MORE ROBUST SOUTHWESTERLY FLOW BECOMES
ESTABLISHED ON TUESDAY.
THE VERY SHALLOW NATURE OF THE COOL LAYER /SEE 12Z KDTX RAOB/ ALLOWS
FOR GREATER TRAPPING OF MOISTURE IN THE LOWER ELEVATION REGIONS OF
METRO DETROIT. HENCE...THAT AREA IS THE LAST TO SCOUR OUT THE FOG
AND LOW CLOUDS. THERE IS STILL AN OPPORTUNITY TO CATCH A GLIMPSE OF
THE SUN PRIOR TO SUNSET...BUT IT WILL NOT BE LONG LIVED. EXPECT FOG
FORMATION TO QUICKLY RESUME AFTER SUNSET AND QUICKLY FILL ACROSS
SOUTHEAST MICHIGAN ONCE AGAIN. HRRR AND HRRRX GUIDANCE HAS BEEN
RATHER SKILLFUL WITH TODAY/S EPISODE AND OFFER REASONABLE DEPICTIONS
FOR THE NOCTURNAL CYCLE ONCE AGAIN TONIGHT - THOUGH MAY BE A LITTLE
TOO PESSIMISTIC EARLY IN THE PROCESS. HOWEVER...THESE SITUATIONS ARE
ALL OR NOTHING ONCE DEVELOPMENT COMMENCES. DENSE FOG IS HIGHLY
LIKELY AGAIN TONIGHT...BUT THE TIMING OF ONSET IS IN QUESTION GIVEN
THE LINGERING LOW CLOUDS ACROSS METRO DETROIT AND SOME DEGREE OF
DEWPOINT SEPARATION IN THOSE LOCATIONS WHERE THE SUN HAS BEEN MORE
ACTIVE.
EQUALLY CHALLENGING WILL BE THE SPATIAL QUALITY OF THE FOG / STRATUS
FIELD. EXPECT THE GLACIAL RIDGE TO EXPERIENCE THE LEAST INFLUENCE
ONCE AGAIN AS ELEVATION INTO THE INVERSION LAYER WILL DIMINISH THE
MOISTURE QUALITY AND FOG PRODUCTION EFFICIENCY. WHILE THE LOWER
ELEVATIONS TO THE SOUTH SHOULD HAVE A SIMILAR OUTCOME AS
WITNESSED TODAY.
THE CLOUDS AND FOG WILL SLOWLY GIVE WAY TO SUN PRIOR TO MIDDAY ON
SUNDAY...WITH THE RIDGE LOCATIONS STARTING MUCH EARLIER. THE DELAYED
START TO INSOLATION WILL ONCE AGAIN KEEP TEMPS BELOW STATISTICAL
GUIDANCE...AND IF CLOUDS REFUSE TO BREAK...MUCH BELOW AS
DEMONSTRATED TODAY.
SURFACE HIGH PRESSURE WILL REMAIN OVER THE GREAT LAKES REGION ON
TUESDAY KEEPING SOUTHEAST MICHIGAN DRY. THIS HIGH WILL SLOWLY DRIFT
TOWARDS THE ATLANTIC COAST ON WEDNESDAY AS A SHORTWAVE TROUGH PIVOTS
THROUGH THE GREAT LAKES RESULTING IN A CHANCE OF RAIN SHOWERS ON
WEDNESDAY. WEAK SURFACE RIDGING WILL KEEP US DRY FOR WEDNESDAY NIGHT
HOWEVER A STRONGER LOW PRESSURE SYSTEM QUICKLY FOLLOWS ON THURSDAY.
BEST CHANCE OF PRECIP WITH THE LOW WILL BE ACROSS THE NORTHERN CWA.
A COLD FRONT TRACKS ACROSS THE SOUTHERN GREAT LAKES ON THURSDAY
NIGHT AND INTO FRIDAY BRINGING A BETTER CHANCE OF RAIN TO THE ENTIRE
CWA. A MORE ORGANIZED SURFACE LOW PRESSURE SYSTEM IS FORECASTED TO
IMPACT THE AREA NEXT WEEKEND...HOWEVER...MODEL TENDENCIES ARE
INCONSISTENT IN TIMING OF THIS SYSTEM AT THIS TIME. HAVE LEFT JUST
CHANCE POPS /30 TO 40 PERCENT/ IN THE FORECAST FOR NOW.
MARINE...
HIGH PRESSURE OVER THE OHIO VALLEY REGION WILL PERSIST THROUGH
THE WEEKEND KEEPING LIGHT SOUTHWESTERLY WINDS ACROSS HURON.
BY MID WEEK A STRONGER FRONT WILL APPROACH FROM THE WEST WITH
INCREASING SPEEDS. HOWEVER WITH UNSEASONABLY MILD AIR IN
PLACE...BOUNDARY LAYER MIXING WILL BE MINIMAL AND WINDS SHOULD
HAVE NO TROUBLE REMAINING SUB-GALE. FOR THE LONGER TERM, THE NEXT
MAJOR FRONTAL SYSTEM IS POSSIBLE NEXT WEEKEND AND COULD BRING
BRIEF GALES TO THE REGION.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...DENSE FOG ADVISORY UNTIL NOON EST TODAY FOR MIZ049-054-055-060>063-
068>070-075-076-082-083.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&
$$
AVIATION.....SC
UPDATE.......MR
DISCUSSION...MANN/RK
MARINE.......05
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1136 PM CST SAT DEC 5 2015
.UPDATE:
Issued at 905 PM CST Sat Dec 5 2015
Visibilities have dropped recently at Effingham, Taylorville, and
Mt. Vernon; though they are not nearly as low as they were at this
time last night. Still expect visibilities to fall into the 1-3SM
range overnight and early Sunday over the Illinois counties. Also
still looks like light rain will move into central and northeast
Missouri on Sunday morning. Latest HRRR and RAP suggest that this
precipitation will not reach the area until mid morning so have
delayed the onset of the light rain by just a bit. Otherwise the
rest of the forecast still looks on track.
Britt
&&
.SHORT TERM: (Through Late Tonight)
Issued at 330 PM CST Sat Dec 5 2015
Upper level shortwave across the Central Plains will move toward the
lower Missouri and middle Mississippi River Valleys tonight. This
will cause a gradual increase in high and mid level clouds from the
west and a slight chance of light rain showers entering parts of
central Missouri by daybreak. Otherwise, last vestages of the
surface ridge to our east will contribute to another night of fog
development, especially across parts of south central and southwest
Illinois. Not sure if the fog will be as widespread or dense as the
past two mornings though as inversion should be weaker. It may be
that the fog remains confined to just the river valleys,
especially across the St. Louis Metropolitan Area.
CVKING
.LONG TERM: (Sunday through Next Saturday)
Issued at 330 PM CST Sat Dec 5 2015
Aforementioned shortwave should pass through the FA during the day
on Sunday. Models are in very good agreement with the speed of
this system, with trof axis near the MO/KS border at 12z
progressing to the lower Ohio River valley by 00z in the evening.
This mornings UA data indicates that AMS is extremely dry over the
central CONUS from the northern Plains into the Gulf coast, but
all of the guidance suggests a strong surge of lower level
moisture into the region ahead of the upper level system later
tonight and into Sunday. So in spite of the initially bone-dry
AMS, believe that the progged moisture return will be adequate
with the expected lift from shortwave to continue mention of light
rain across the CWA during the day, with the precip then winding
down east of the Mississippi River on Sunday evening. Have
generally gone with consensus of MOS PoPs...in the chance/slight
chance range.
The cloudiness associated with this system will likely make
Sunday`s high temps 5 to 10 degrees cooler than those of today
along and west of the Mississippi River.
However, more mild early December weather appears to be in the
offing for much of the upcoming work week, as a westerly flow
regime dominates across the CONUS. This pattern will keep the
colder air bottled up well to the north of the region, so
temperatures should remain well above early December averages and
have maintained going trends by skewing forecast towards the
warmer guidance. GFS would suggest very warm temps during the
latter half of the week, but did not go that extreme as there is
more than a little discrepancy between the GFS and ECMWF in the
intensity of the Thursday shortwave and the resultant temperature
advection associated with it.
Disturbances embedded in this zonal flow are progged to clip the
area about every 24 to 36 hours through Thursday, however with
such rapid movement believe that the moisture available to each
of these features will be fairly limited. This, combined with the
fact that the main dynamics will be over the upper Missouri and
upper Mississippi Valleys, should mean the rain threat in our FA
will remain quite low.
However this may change by the end of the forecast period, as
there is consensus in the medium range guidance that a much
deeper trof that forms over the western U.S. later in the work
week begins to push into the Plains. Some warm-advection driven
rain could threaten as early as Thursday night/Friday, but the
better chances should hold off until next Saturday, when upper
level dynamics associated with upper trof push into the mid-
Mississippi Valley.
Truett
&&
.AVIATION: (For the 06z TAFs through 06z Sunday Night)
Issued at 1130 PM CST Sat Dec 5 2015
Not many changes from the prev TAFs. With CI remaining in place
overnight, believe FG development impacting SUS/CPS appears
unlikely. Sely winds will become swly ahead of the approaching
cdfnt, then wly, then nwly behind the fnt. Cigs will gradually
lower ahead of the fnt and expected to reach MVFR along and just
behind the fnt. Can not rule out IFR cigs impacting all sites
except for COU. However, if these cigs develop, believe they will
be short lived. Mdls also indicate that FG may develop after
clouds clear out. This seems unlikely with drier air advecting
into the region.
Tilly
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
322 AM EST SUN DEC 6 2015
.SYNOPSIS...
HIGH PRESSURE WILL PROVIDE DRY...MOSTLY CLEAR...AND RELATIVELY
MILD TEMPERATURES THROUGH THE REMAINDER OF THE WEEKEND AND INTO
NEXT WEEK. HIGH TEMPERATURES WILL BE GENERALLY IN THE 40S WITH
LOWS IN THE 20S AND 30S.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 1254 AM EST SUNDAY...MORE TWEAKS TO SKY COVER ACROSS OUR
NORTHERN NY COUNTIES THROUGH THE OVERNIGHT HOURS PER LATEST IR
SATELLITE IMAGERY. 01 UTC RAP LOW LEVEL MOISURE PROGS SHOWING THE
BEST IDEA FOR ITS EVOLUTION AND MOVEMENT OVERNIGHT, BUT THAT`S NOT
SAYING TOO MUCH AS ALL MODELS ARE STRUGGLING TO VARYING DEGREES ON
THIS. IT`S ALSO ANYONE`S GUESS ON ACTUAL TEMPERATURE TRENDS AND
EVENTUAL OVERNIGHT LOWS GIVEN CLOUDY/CLEAR AREAS AND THE FACT THAT
MANY SITES HAVE ALREADY REACHED FORECAST MINIMUM VALUES AS OF 900
PM. SAVING GRACE IS THE FACT THAT SFC DEWPOINT DEPRESSIONS ARE
RATHER SMALL AND WITH THE LACK OF WIND OR ADVECTIVE PROCESSES I
FEEL MOST SITES SHOULD HOLD STEADY OR ONLY SEE READINGS FALL A FEW
MORE DEGREES. WITH THE NARROW TD DEPRESSIONS IN PLACE PATCHY
MIST/FOG STILL A GOOD BET HERE AND THERE, MOST PREVALENT ACROSS
PORTIONS OF EASTERN VERMONT (KCDA ALREADY SHOWING PATCHY BR/FG).
OUTSIDE OF THESE ADJUSTMENTS FORECAST REMAINS IN GOOD SHAPE. HAVE
A GREAT NIGHT.
PRIOR DISCUSSION FROM 247 PM EST SATURDAY...
HEADING INTO SUNDAY...SHOULD SEE ANY RESIDUAL CLOUDS AND/OR
PATCHY FOG DISSIPATE IN THE MORNING WITH MOSTLY SUNNY SKIES.
TEMPERATURES WILL BE QUITE MILD FOR EARLY DECEMBER...WITH HIGHS
47-52F.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/...
AS OF 316 AM EST SUNDAY...UPPER LOW MOVES SOUTHEAST ACROSS MID
ATLANTIC STATES MONDAY. THIS PLACES FORECAST AREA IN WEAK
TROUGHINESS WHILE WEAK SURFACE BOUNDARY SLIDES ACROSS THE AREA.
EXPECT PARTLY CLOUDY SKIES WITH THE SLIGHT CHANCE OF A SHOWER
ACROSS THE CANADIAN BORDER. TEMPS A LITTLE COOLER BUT STILL ABOVE
NORMAL WITH HIGHS IN THE LOWER TO MID 40S.
UPPER LOW MOVES TO MID ATLANTIC COAST MONDAY NIGHT...SPAWNING
DEVELOPMENT OF SURFACE LOW OFFSHORE. THIS SYSTEM THEN TRACKS TO THE
EAST DURING TUESDAY...PASSING WELL SOUTH OF THE 40N 70W BENCHMARK.
EXPECT SOME CLOUDS...BUT DRY WEATHER.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
AS OF 316 AM EST SUNDAY...ABOVE NORMAL TEMPERATURES AND MAINLY DRY
CONDITIONS EXPECTED FOR THE LONG TERM PORTION OF THE FORECAST.
WEAK SURFACE HIGH PRESSURE WILL PREVAIL OVER THE REGION TUESDAY
NIGHT INTO WEDNESDAY...WHILE WEAK SHORTWAVE ENERGY MOVES ACROSS THE
REGION. THE RESULT WILL BE PARTLY CLOUDY SKIES AND CONTINUED DRY
CONDITIONS. MORE VIGOROUS SHORTWAVE WILL MOVE INTO OHIO VALLEY AND
MID ATLANTIC REGION WEDNESDAY NIGHT...THEN MOVE TO MID ATLANTIC
COAST THURSDAY. ASSOCIATED SURFACE LOW PASSES NEAR OR SOUTH OF 40N
70W THURSDAY. EXPECT MOST OF PRECIPITATION WITH THIS SYSTEM TO
REMAIN SOUTHEAST OF OUR AREA...BUT ENOUGH UNCERTAINTY FOR AT LEAST
A MENTION OF SLIGHT CHANCE TO LOW CHANCE SHOWERS FOR THURSDAY.
ANOTHER SHORTWAVE ASSOCIATED WITH WARM FRONT WILL LIFT NORTHEAST
ACROSS THE AREA FRIDAY INTO SATURDAY. MAINLY DRY CONDITIONS WITH
VARIABLY CLOUDY SKIES...JUST SLIGHT CHANCE FOR A FEW SHOWERS AS WE
TRANSITION TO DEEP SOUTH-SOUTHWEST FLOW OF MILD AIR FOR NEXT
WEEKEND.
TEMPERATURES ARE EXPECTED TO BE ABOUT 5 TO 10 DEGREES ABOVE NORMAL
WEDNESDAY AND THURSDAY WITH HIGHS IN THE LOWER TO MID 40S. EVEN
MILDER TEMPERATURES WILL FOLLOW FOR FRIDAY AND SATURDAY WHEN HIGH
TEMPS ARE EXPECTED TO BE AROUND 50. MIN TEMPS WILL BE IN THE MID 20S
TO LOWER 30S EARLY IN THE PERIOD...THEN 30S LATER IN THE WEEK WITH
MORE CLOUD COVER AND DEVELOPING SOUTHERLY FLOW.
&&
.AVIATION /08Z SUNDAY THROUGH THURSDAY/...
THROUGH 06Z MONDAY...DIFFICULT FORECAST WITH CLOUDS OVER NORTHERN
NEW YORK BUT NOT VERMONT. FG HAS ALREADY DEVELOPED AT MPV AND SLK
DOWN TO VLIFR...EXPECT THESE STATIONS TO STAY DOWN MOST OF THE
NIGHT. MSS HAS MVFR CEILINGS WHICH SHOULD KEEP FOG FROM FORMING
THERE. NOT EXPECTING FOG FORMATION AT THE REST OF THE TAF
SITES...THOUGH MAYBE TEMPO TOWARDS SUNRISE...WILL CONTINUE TO
MONITOR. SHOULD HAVE MOSTLY SUNNY SKIES FOR THE DAYLIGHT HOURS.
OUTLOOK 06Z MONDAY THROUGH THURSDAY...
THROUGH 00Z THURSDAY...MAINLY VFR UNDER HIGH PRESSURE.
00Z THURSDAY ONWARD...VFR WITH PERIODS OF MVFR POSSIBLE IN LIGHT
SHOWERS WITH WEAK UPPER LEVEL DISTURBANCE.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MUCCILLI
NEAR TERM...JMG/NEILES/MUCCILLI
SHORT TERM...RJS
LONG TERM...RJS
AVIATION...NEILES/MV
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
107 AM EST SUN DEC 6 2015
.SYNOPSIS...
HIGH PRESSURE WILL PROVIDE DRY...MOSTLY CLEAR...AND RELATIVELY
MILD TEMPERATURES THROUGH THE REMAINDER OF THE WEEKEND AND INTO
NEXT WEEK. HIGH TEMPERATURES WILL BE GENERALLY IN THE 40S WITH
LOWS IN THE 20S AND 30S.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 1254 AM EST SUNDAY...MORE TWEAKS TO SKY COVER ACROSS OUR
NORTHERN NY COUNTIES THROUGH THE OVERNIGHT HOURS PER LATEST IR
SATELLITE IMAGERY. 01 UTC RAP LOW LEVEL MOISURE PROGS SHOWING THE
BEST IDEA FOR ITS EVOLUTION AND MOVEMENT OVERNIGHT, BUT THAT`S NOT
SAYING TOO MUCH AS ALL MODELS ARE STRUGGLING TO VARYING DEGREES ON
THIS. IT`S ALSO ANYONE`S GUESS ON ACTUAL TEMPERATURE TRENDS AND
EVENTUAL OVERNIGHT LOWS GIVEN CLOUDY/CLEAR AREAS AND THE FACT THAT
MANY SITES HAVE ALREADY REACHED FORECAST MINIMUM VALUES AS OF 900
PM. SAVING GRACE IS THE FACT THAT SFC DEWPOINT DEPRESSIONS ARE
RATHER SMALL AND WITH THE LACK OF WIND OR ADVECTIVE PROCESSES I
FEEL MOST SITES SHOULD HOLD STEADY OR ONLY SEE READINGS FALL A FEW
MORE DEGREES. WITH THE NARROW TD DEPRESSIONS IN PLACE PATCHY
MIST/FOG STILL A GOOD BET HERE AND THERE, MOST PREVALENT ACROSS
PORTIONS OF EASTERN VERMONT (KCDA ALREADY SHOWING PATCHY BR/FG).
OUTSIDE OF THESE ADJUSTMENTS FORECAST REMAINS IN GOOD SHAPE. HAVE
A GREAT NIGHT.
PRIOR DISCUSSION FROM 247 PM EST SATURDAY...
HEADING INTO SUNDAY...SHOULD SEE ANY RESIDUAL CLOUDS AND/OR
PATCHY FOG DISSIPATE IN THE MORNING WITH MOSTLY SUNNY SKIES.
TEMPERATURES WILL BE QUITE MILD FOR EARLY DECEMBER...WITH HIGHS
47-52F.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/...
AS OF 242 PM EST SATURDAY...SURFACE HIGH MOVES OFFSHORE SUNDAY
NIGHT AND UPPER LEVEL RIDGING SLIDES EAST AS WELL. WEAK UPPER LOW
SLIDES SOUTH ACROSS MID-ATLANTIC MONDAY BUT THIS PLACES AREA IN
WEAK TROFINESS WITH A WEAK SURFACE TROF/FRONT SLIDING ACROSS FA
WITH SOME CLOUDS AND A SLIGHT CHANCE OF SHOWER ACROSS THE CANADIAN
BORDER. TEMPS JUST A FEW DEGREES LOWER THAN SUNDAY.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 242 PM EST SATURDAY...A SOMEWHAT CYCLONIC-ZONAL FLOW
THROUGH THIS PERIOD WITH PREDOMINANTLY WESTERLY FLOW BECOMING
CYCLONIC AT TIMES AS SHORTWAVES DROP INTO MEAN FLOW.
WEAK SYSTEMS WITH A CHANCE OF RAIN/SNOW SHOWERS LATE WED NGT INTO
THURSDAY THEN PERHAPS ANOTHER SLIGHT CHANCE OF SHOWERS ON FRIDAY
BEFORE MORE RIDGING POSSIBLE FOR NEXT WEEKEND. THERE ARE SOME TIMING
DIFFERENCE IN MODELS BUT GIVEN THE CUSTOMARY TIMING DIFFERENCES IN A
PATTERN LIKE THIS AND LITTLE PRECIPITATION AS WELL...NOTHING OF ANY
CONSEQUENCE.
THIS FLOW CONTINUES THE ABOVE NORMAL PATTERN ACROSS THE NORTHEAST
WITH HIGH TEMPERATURES NEAR OR JUST ABOVE SEASONABLE TUESDAY WITH
WARMING AS THE WEEK PROGRESSES.
ATTM...NO CLEAR INDICATIONS OF ANY ACCUMULATING SNOWFALL IN THE
VALLEYS (OR EVEN MOUNTAINS) FOR THIS UPCOMING WEEK.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
THROUGH 06Z MONDAY...DIFFICULT FORECAST WITH CLOUDS OVER NORTHERN
NEW YORK BUT NOT VERMONT. FG HAS ALREADY DEVELOPED AT MPV AND SLK
DOWN TO VLIFR...EXPECT THESE STATIONS TO STAY DOWN MOST OF THE
NIGHT. MSS HAS MVFR CEILINGS WHICH SHOULD KEEP FOG FROM FORMING
THERE. NOT EXPECTING FOG FORMATION AT THE REST OF THE TAF
SITES...THOUGH MAYBE TEMPO TOWARDS SUNRISE...WILL CONTINUE TO
MONITOR. SHOULD HAVE MOSTLY SUNNY SKIES FOR THE DAYLIGHT HOURS.
OUTLOOK 06Z MONDAY THROUGH THURSDAY...
THROUGH 00Z THURSDAY...MAINLY VFR UNDER HIGH PRESSURE.
00Z THURSDAY ONWARD...VFR WITH PERIODS OF MVFR POSSIBLE IN LIGHT
SHOWERS WITH WEAK UPPER LEVEL DISTURBANCE.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MUCCILLI
NEAR TERM...JMG/NEILES/MUCCILLI
SHORT TERM...SLW
LONG TERM...SLW
AVIATION...NEILES/MV
AREA FORECAST DISCUSSION
NWS BUFFALO NY
106 AM EST SUN DEC 6 2015
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO BRING DRY WEATHER SUNDAY THROUGH
TUESDAY ALTHOUGH LOW CLOUDS WILL LIMIT SUNSHINE AT TIMES. A SERIES
OF WEAK SYSTEMS WILL BRING A CHANCE OF A FEW LIGHT SHOWERS LATER IN
THE WEEK. TEMPERATURES WILL REMAIN WELL ABOVE NORMAL THROUGH THE
NEXT WEEK AND BEYOND.
&&
.NEAR TERM /THROUGH TODAY/...
FOG AND LOW STRATUS IS THE PRIMARY FORECAST CONCERN OVERNIGHT INTO
SUNDAY MORNING. A THICK AREA OF STRATUS EAST OF LAKE ONTARIO WILL
LIKELY REMAIN IN PLACE OVERNIGHT... WITH THE REST OF THE FORECAST
AREA AT RISK FOR FOG FORMATION. LOW LEVEL MOISTURE REMAINS LOCKED IN
PLACE THIS EVENING UNDER A STRONG SUBSIDENCE INVERSION PER 00Z BUF
SOUNDING AND RECENT AVIATION SOUNDINGS. THE CLEARING SKIES THIS
EVENING ACROSS WESTERN NY WILL LIKELY PROMOTE ADDITIONAL FOG AND
VERY LOW STRATUS DEVELOPMENT OVERNIGHT AS RADIATIONAL COOLING
QUICKLY RE-SATURATES THE LOW LEVELS.
EXPECT FOG AND STRATUS TO BEGIN TO REFORM BY LATE EVENING AND THEN
EXPAND TO COVER MUCH OF THE AREA BEFORE DAYBREAK SUNDAY. UNLIKE THE
PAST FEW DAYS...FOG MAY BE MORE OF AN ISSUE LATE TONIGHT AND SUNDAY
MORNING. 12Z AND 18Z NAM BUFKIT POINT SOUNDINGS SUGGEST THE
DEVELOPMENT OF A SURFACE BASED INVERSION...AND INITIALLY CLEAR SKIES
EARLY TONIGHT ALSO SUGGEST MORE OF A FOG SCENARIO.
FOG WAS WIDESPREAD AND DENSE THIS MORNING JUST UPSTREAM ACROSS MUCH
OF OHIO...LOWER MICHIGAN...AND INDIANA. A BACKWARDS TRAJECTORY
FORECAST FROM THE HYSPLIT MODEL SHOWS AIR ARRIVING IN BUFFALO AT 12Z
SUNDAY HAS ORIGINS ACROSS EASTERN OHIO AND CENTRAL LAKE ERIE...WHERE
DENSE FOG WAS FOUND THIS MORNING. GIVEN THE UPSTREAM TRENDS AND
FORECAST SOUNDINGS...EXPECT FOG AND STRATUS TO BECOME WIDESPREAD
AGAIN LATE TONIGHT.
THE HRRR AND NAM DO NOT COMPLETELY AGREE ON HOW THE FOG DEVELOPMENT
WILL EVOLVED... BUT THE GENERAL CONSUS SUPPORTS MUCH OF WESTERN NY
SEEING FOG DEVELOP OVERNIGHT. EXPECT ONE AREA OF TRUE RADIATION FOG
TO DEVELOP NORTHWARD FROM NW PA (WHERE 11-3.9 IMAGERY AND OBS SHOW
DENSE FOG CURRENTLY IN PLACE) INTO THE SOUTHERN TIER TONIGHT... WITH
MAINLY INTERIOR VALLEYS AND LOW-LYING LOCATIONS ALONG RIVER VALLEYS
DEVELOPING FOG. THE OTHER AREA OF FOG/LOW STRATUS SHOULD DEVELOP
EASTWARD OUT OF ONTARIO... WITH ADDED MOISTURE FROM LAKE ERIE AS THE
FLOW TURNS MORE SOUTHWESTERLY OVERNIGHT...ENHANCED BY THE DEVELOPING
LAKE BREEZE AND THE SURFACE HIGH SHIFTING EASTWARD. THUS THIS SHOULD
HELP TO SPREAD AREAS OF FOG FROM THE NIAGARA FRONTIER ACROSS THE
ROCHESTER.
THE ADDITIONAL WRINKLE IS THAT TEMPERATURES WILL BE NEAR OR JUST
BELOW FREEZING ACROSS INTERIOR AND RURAL LOCATIONS... AND THUS THERE
IS POTENTIAL FOR SOME PATCHY BLACK ICE FORMATION OVERNIGHT WHERE
DENSE FOG DEVELOPS.
SUNDAY EXPECT FOG AND LOW STRATUS TO HOLD STRONG THROUGH MUCH OF THE
MORNING BENEATH A STRONG SUBSIDENCE INVERSION. THE LOW CLOUDS SHOULD
THEN MIX OUT IN A SIMILAR FASHION TO TODAY WITH INCREASING AMOUNTS
OF SUNSHINE DURING THE AFTERNOON. MODEL GUIDANCE IS NOT HANDLING THE
FOG AND STRATUS POTENTIAL PARTICULARLY WELL. WITH THIS IN
MIND...HAVE FORECAST TEMPERATURES ABOVE GUIDANCE TONIGHT AND BELOW
GUIDANCE ON SUNDAY. THIS WILL TRANSLATE TO LOWS IN THE MID 30S ON
THE LAKE PLAINS AND UPPER 20S TO LOWER 30S ACROSS THE INTERIOR
SOUTHERN TIER AND LEWIS COUNTY. HIGHS ON SUNDAY SHOULD REACH THE
UPPER 40S TO LOWER 50S ACROSS LOWER ELEVATIONS ASSUMING THE FOG AND
STRATUS BURNS OFF BY MIDDAY.
&&
.SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...
A ZONAL PACIFIC FLOW WILL BE FOUND STRETCHED ACROSS THE CONUS MUCH
OF NEXT WEEK. THIS WILL KEEP GENERALLY FAIR WEATHER IN PLACE WITH
TEMPERATURES RUNNING ON THE MILDER SIDE OF NORMAL FOR EARLY
DECEMBER. SURFACE RIDGING WILL EXTEND SOUTH FROM NORTH OF THE GREAT
LAKES WITH THE ONLY STORM SYSTEM EAST OF THE ROCKIES BEING A MID-
LEVEL CLOSED LOW THAT WILL PASS SOUTH OF OUR FORECAST AREA ACROSS
THE OHIO VALLEY MONDAY THEN OFF THE MID-ATLANTIC COAST ON TUESDAY.
SYNOPTIC LIFT AND MOISTURE WILL BE COLLOCATED WITH THIS LOW CENTER
WITH NO THREAT OF PRECIPITATION FOR OUR FORECAST AREA.
SUNDAY NIGHT...CLEAR TO PARTLY CLOUDY SKIES ACROSS WESTERN AND
CENTRAL NEW YORK WILL ALLOW GOOD RADIATIONAL COOLING AND THE
POTENTIAL FOR PATCHY RIVER VALLEY FOG IN THE SOUTHERN TIER. THIS
COULD MAKE FOR SOME SLICK ROADWAYS IN AREAS WHERE SURFACE TEMPS FALL
BELOW FREEZING. LOWS WILL RANGE FROM THE M30S NEAR THE LAKES TO THE
U20S IN THE SOUTHERN TIER VALLEYS.
MONDAY INTO TUESDAY HAVE LEANED ON THE 05/12Z NAM SHOWING A RETURN
OF LOW CLOUDS UNDER LIGHT NORTHERLY FLOW TRAPPING LAKE MOISTURE
BENEATH A 925MB SUBSIDENCE INVERSION. THE FORECAST CLOUD COVER HAS
THEREFORE BEEN INCREASED TO MOSTLY CLOUDY. THERE MAY ALSO BE A
POTENTIAL FOR SOME PATCHY DRIZZLE BUT CONFIDENCE IS TOO LOW AT THIS
TIME TO INCLUDE IN THE FORECAST.
UNDER A LIGHT NORTHERLY FLOW MONDAY TEMPERATURES WILL RUN CLOSER TO
NORMAL WITH HIGHS TOPPING OUT IN THE LOW 40S FOR MOST. WINDS VEER
AROUND TO THE SOUTH ON TUESDAY AHEAD OF A COLD FRONT/SURFACE TROUGH
CROSSING THE UPPER MIDWEST. TEMPERATURES WILL EDGE UP A LITTLE
WARMER WITH HIGHS RANGING IN THE L/M 40S. OVERNIGHT LOWS WILL
CONTINUE TO RANGE FROM THE M30S NEAR THE LAKES TO U20S WELL INLAND.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
A LOW AMPLITUDE PACIFIC FLOW WILL CONTINUE THROUGH MUCH OF THE REST
OF NEXT WEEK WITH MEDIUM RANGE MODELS THEN INDICATING A POTENTIAL
FOR A MORE AMPLIFIED 500MB PATTERN GOING INTO NEXT WEEKEND WHICH
WOULD BRING WELL ABOVE NORMAL WARMTH.
05/12Z GFS AND ECMWF OPERATIONAL MODELS ALONG WITH GEFS ENSEMBLES
CONTINUE TO SHOW DISAGREEMENT IN THE 500MB PATTERN FOR WEDNESDAY AND
THURSDAY. EACH MODEL/MEMBER IS SHOWING DIFFERENCE IN TIMING AND
LOCATION OF SUBTLE SHORTWAVE TROUGHS MOVING ACROSS THE CONUS. THIS
CONTINUES TO MAKE FOR A LOW CONFIDENCE FORECAST OF ANY MINOR
PRECIPITATION EVENTS AS THESE SHORTWAVES CROSS THE EASTERN GREAT
LAKES. WILL CONTINUE SLIGHT/LOW CHANCE POPS FOR SHOWERS WEDNESDAY
INTO THURSDAY UNTIL CONFIDENCE IN TIMING AND LOCATION INCREASES.
THE PATTERN LOOKS TO AMPLIFY GOING INTO THE WEEKEND WHICH ALSO
LEADS TO A BETTER POTENTIAL FOR MORE SIGNIFICANT WEATHER ALTHOUGH
TIMING BETWEEN THE MODELS REMAINS MISALIGNED. THIS WILL KEEP SLIGHT
CHANCE POPS INTO THE WEEKEND. BETTER CONFIDENCE IS FOUND IN THE
POTENTIAL FOR AN AMPLIFIED RIDGE TO BUILD OVER THE EASTERN STATES
THIS WEEKEND. WHILE PACIFIC FLOW ALOFT AND SOUTHERLY SURFACE WINDS
WILL HELP BOOST TEMPS TOWARD 50 THURSDAY AND FRIDAY...AN AMPLIFIED
500MB RIDGE /IN WHICH NAEFS ENSEMBLES BUILD OVER +2SD/ WOULD MAKE
60S A POSSIBILITY FOR THE WEEKEND.
LOOKING FURTHER OUT INTO THE SECOND FULL WEEK OF DECEMBER...BOTH
THE ECMWF AND GFS BASED ENSEMBLES ARE IN STRONG AGREEMENT THAT THE
PACIFIC BASED FLOW COULD TEMPORARILY BREAK DOWN OVER THE LOWER 48.
A NICE SIZED CHUNK OF -12 TO -16C H85 AIR IS ADVERTISED TO MOVE
FROM THE CANADIAN PRAIRIES INTO THE UPPER MISSISSIPPI VALLEY.
SHOULD THIS AIRMASS MAKE IT TO THE OHIO VALLEY...IT WOULD BE IN A
FAVORABLE POSITION TO EVENTUALLY GENERATE SOME SIGNIFICANT LAKE
SNOWS EAST OF BOTH LAKES ERIE AND ONTARIO. THERE ARE PLENTY OF `IFS`
WITH THIS SCNEARIO THOUGH...BUT IT WILL BE INTERESTING TO KEEP AN
EYE ON AS WE MOVE DEEPER INTO PREPARATIONS FOR THE UPCOMING
HOLIDAY SEASON.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
CLEAR VFR SKIES WILL ALLOW FOR IFR/LIFR FOG DEVELOPMENT OVERNIGHT.
FOG AND LOW STATUS HAS ALREADY DEVELOPED ACROSS NW PA/NE OH AND
SOUTHERN ONTARIO...AND EXPECT THIS WILL EXPAND NORTH AND EASTWARD
ACROSS WESTERN NY OVERNIGHT AND REMAIN IN PLACE THROUGH SUNDAY
MORNING. NEED TO STRESS THIS IS AN ALL OR NOTHING SITUATION FOR
FOG DEVELOPMENT...AND WHILE WIDESPREAD IFR CIGS/VIS AT OR BELOW
AIRFIELD MINIMUMS IS THE MOST LIKELY OUTCOME...IF THIS FOG DOESNT
DEVELOP INTO A TAF SITE IT WILL LIKELY REMAIN VFR.
ON SUNDAY EXPECT WIDESPREAD IFR IN FOG AND LOW STRATUS TO PERSIST
THROUGH MUCH OF THE MORNING BEFORE SCATTERING OUT TO VFR DURING THE
AFTERNOON. AGAIN...CONDITIONS MAY DROP TO AT OR BELOW AIRFIELD
MINIMUMS FOR A TIME SUNDAY MORNING IF THE FOG BECOMES WIDESPREAD.
OUTLOOK...
MONDAY AND TUESDAY...A CHANCE OF MVFR AND POSSIBLY IFR IN STRATUS.
WEDNESDAY AND THURSDAY...MAINLY VFR.
&&
.MARINE...
A LARGE AREA OF HIGH PRESSURE WILL CONTINUE TO DOMINATE FROM THE
OHIO VALLEY ACROSS THE LOWER LAKES SUNDAY THROUGH THE FIRST HALF OF
NEXT WEEK. THIS WILL PROVIDE A RARE LONG STRETCH OF LIGHT WINDS AND
FLAT WAVE ACTION ON LAKES ERIE AND ONTARIO THROUGH THE MIDDLE OF
NEXT WEEK.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...HITCHCOCK
NEAR TERM...CHURCH/HITCHCOCK
SHORT TERM...SMITH
LONG TERM...SMITH
AVIATION...CHURCH/HITCHCOCK/TMA
MARINE...HITCHCOCK
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
302 AM EST SUN DEC 6 2015
.SYNOPSIS...
AN UPPER LOW AND WEAK OFFSHORE SYSTEM WILL BRING MAINLY
COASTAL RAIN LATE TONIGHT AND MONDAY. HIGH PRESSURE WILL BRING
BACK SUNSHINE AND SEASONABLE TEMPERATURES THROUGH THE MIDDLE OF
THE WEEK POSSIBLY FOLLOWED BY A WEEKEND WARMUP.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 330 AM SUNDAY...COOL HIGH PRESSURE CENTERED TO THE NORTH
WILL WEAKEN TODAY AND TONIGHT AS A COASTAL TROUGH FORMS OFFSHORE.
LOW LEVEL MOISTURE ADVECTION IN COMBINATION WITH LIFT ASSOCIATED
WITH THIS NASCENT TROUGH AND A VIGOROUS APPROACHING SHORT WAVE
WILL INCREASE THE CHANCES FOR STRATIFORM RAIN OVERNIGHT...MAINLY
AFTER MIDNIGHT IN THE PRE-DAWN HOURS OF MONDAY. UNTIL THEN...THE
DAY WILL START OFF WITH AT LEAST PATCHY STRATUS ALONG THE COAST
ADVECTING IN FROM THE OCEAN AND SPREADING INLAND. MUCH OF THIS
WILL LIFT AND SCATTER OUR THIS AFTERNOON...WITH OVERCAST
CONDITIONS RETURNING FOR THE OVERNIGHT PERIOD. MILD AND SLIGHTLY
ABOVE AVERAGE TEMPERATURES IN STORE FOR TODAY...WITH MODEL
CONSENSUS GIVING US HIGHS IN THE LOWER 60S MOST PLACES...WITH LOWS
IN THE MID 40S.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 3 AM SUNDAY...GUIDANCE CONTINUES TO SHOW THAT DESPITE A FAIRLY
POTENT SHORTWAVE COMING ACROSS ON MONDAY THAT THE DEEPEST MOISTURE
AND THUS BEST RAIN CHANCES WILL REMAIN QUITE CONFINED TO THE COAST.
GIVEN THAT THERE COULD BE A CONSIDERABLE WEST-TO-EAST GRADIENT IN
BOTH RAIN CHANCES AND AMOUNTS GETTING THE AMOUNTS RIGHT IS A BIT
TRICKY AS THEY WILL BE HIGHLY SUBJECT TO SMALL DEVIATIONS IN THE
PATH OF THE FLAT WAVE OFFSHORE THAT MOVES UP THE COAST. COASTAL NC
LOOKS TO NET THE MOST RAIN WITH ABOUT A THIRD OF AN INCH POSSIBLE.
LOW AMPLITUDE ALOFT TAKES OVER MONDAY NIGHT AND THUS RAPID DRYING
FOR CLEARING SKY THAT WILL PERSIST INTO TUESDAY. ANY COOL ADVECTION
ASSOC WITH THIS SYSTEM IS UNDONE ON TUESDAY SO TEMPERATURES TUESDAY
WILL BE NEAR CLIMO IN A WEAKLY WARM ADVECTING BUT ALSO SHALLOW MIXED
REGIME.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 3 AM SUNDAY...UPPER TROUGH POISED TO SWING THROUGH OUR
LONGITUDE LATE WEDNESDAY OR WEDNESDAY NIGHT. THIS FEATURE WILL BE
MOISTURE-CHALLENGED ENOUGH AND ALSO HAVE A POOR ENOUGH SURFACE
REFLECTION TO NOT BRING MEANINGFUL RAIN CHANCES. FLOW QUICKLY
FLATTENS THURSDAY FOR ANOTHER SEASONABLE AND DRY DAY. MODELS IN GOOD
AGREEMENT THAT A FAIRLY STRONG MID LEVEL RIDGE AND LOW LEVEL RETURN
FLOW THEN GET UNDERWAY BUT NOT SO MUCH IN THE TIMING. RIDGE MAY WELL
BE IN ITS FORMATIVE STAGES ON FRIDAY ACCORDING TO QUICKER PROGS
WHEREAS OTHERS WISH TO DELAY THINGS BY ABOUT A DAY. EITHER WAY NO
PRECIP CHANCES TO BE HAD. THE TROUGH OVER THE WESTERN U.S. WILL
BECOME QUITE DEEP WHICH COULD TRANSLATE TO SOME LOCAL WEATHER NOT
LONG AFTER THE LONG TERM PERIOD.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
AS OF 06Z...VFR CONDITIONS WILL CONTINUE FOR THE NEXT FEW HOURS
WITH NORTHEAST FLOW ACROSS THE TAF SITES. MODELS CONTINUE TO SHOW
LOW-LEVEL MOISTURE INCREASING OVERNIGHT AND THE 00 UTC
EXPERIMENTAL RUN OF THE HRRR IS SHOWING IF STRATUS AND FOG DEVELOPING
OVER ALL TAF SITES EXCEPT KMYR AND KCRE GENERALLY BETWEEN 9 AND 12
UTC BEFORE BREAKING UP AFTER SUNRISE.
EXTENDED AVIATION OUTLOOK...POTENTIAL FOR RESTRICTIONS TO DEVELOP
ON MONDAY WITH LOW CLOUDS AND SHOWERS. OTHERWISE EXPECT VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 330 AM SUNDAY...SMALL CRAFT ADVISORY REMAINS IN EFFECT
THROUGH THE AFTERNOON HOURS AS A WEAKENING HIGH PRESSURE SYSTEM
CENTERED TO THE NORTH MAINTAINS A COOL NORTHEASTERLY FLOW THROUGH
THE PERIOD. HAVE CANCELED THE ADVISORY FOR THE OVERNIGHT PORTION
OF THE FORECAST AS SEAS WILL HAVE DROPPED BELOW CRITERIA BY THEN.
WINDS HAVE ALREADY DROPPED BELOW SMALL CRAFT ADVISORY CRITERIA.
MOST AREAS WILL EXPERIENCE NE WINDS IN THE 15 TO 20 KT RANGE
TODAY...WITH 4 TO 6 FT SEAS. EXPECT GRADUALLY IMPROVING CONDITIONS
THIS EVENING...WITH SEAS IN THE 3 TO 5 FT RANGE OVERNIGHT.
SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 3 AM SUNDAY... AN UPPER LOW WILL SWING BY JUST NORTH OF THE
AREA ON MONDAY. DESPITE THIS FEATURE HAVING SOME STRENGTH TO IT
HOWEVER THERE WILL BE LITTLE TO NO SURFACE REFLECTION. WHILE THERE
WILL BE SOME VISIBILITY-LIMITING SHOWERS AROUND WIND AND SEAS SHOULD
ACTUALLY CONTINUE THEIR GRADUAL ABATING TREND AND NO HEADLINES ARE
ANTICIPATED AT THIS TIME. MONDAY NIGHT AS THIS SYSTEM MOVES OFFSHORE
IT DOES APPEAR TO INTERACT WITH LOW LEVEL FRONTAL BOUNDARY AND LEAD
TO DEEPENING LOW PRESSURE WILL OFF DELMARVA COAST. THIS MAY SLIGHTLY
AND BRIEFLY BOLSTER LOCAL WINDS BUT BY TUESDAY THE DIMINISHING TREND
RESUMES AS HIGH PRESSURE BUILDS WEAKLY INTO THE SOUTHEASTERN U.S.
LONG TERM /WEDNESDAY THROUGH THURSDAY/...
AS OF 3 AM SUNDAY... PRESSURE PATTERN GROWS SO WEAK ON WEDNESDAY
THAT WE ARE LIKELY LOOKING AT VERY LIGHT WINDS AND CONSIDERABLE
VARIABILITY IN WIND DIRECTION. THIS WILL GIVE SEAS A CHANCE TO
SETTLE TO NEAR MINIMAL VALUES OF 2 FT OR LESS. ANOTHER UPPER SYSTEM
MOVING RAPIDLY OFF THE VA COAST ON THURSDAY WILL BRING A TURN TO W
OR NW AND A VERY SHORT-LIVED SURGE IN WIND SPEED. THIS SYSTEM WILL
MOVE QUICKLY HOWEVER AND EXPECT THAT A GENERAL 10 KT FORECAST WILL
STILL BE THE FLAVOR OF MOST OF THE DAY AND EVENING.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS EVENING FOR AMZ250-
252-254-256.
&&
$$
SYNOPSIS...MBB
NEAR TERM...REK
SHORT TERM...MBB
LONG TERM...MBB
AVIATION...DRH
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1238 AM EST SUN DEC 6 2015
.SYNOPSIS...
A FRONT WILL REMAINED STALLED JUST SOUTH OF FLORIDA AS STRONG
HIGH PRESSURE BUILDS IN FROM THE WEST THROUGH THE WEEKEND. A
COASTAL TROUGH WILL DEVELOP OFFSHORE LATE SUNDAY. RAIN WILL
SPREAD OVER THE REGION AS THE TROUGH SLOWLY LIFTS NORTH SUNDAY
NIGHT INTO MONDAY. LOW PRESSURE IS EXPECTED TO DEVELOP NEAR CAPE
HATTERAS EARLY NEXT WEEK AND THEN MOVE NORTH. DRY AND SEASONABLE
WEATHER DURING THE MIDDLE OF NEXT WEEK WILL BE FOLLOWED BY A
SUBTLE AND GRADUAL WARMUP.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 1230 AM SUNDAY...NO CHANGES TO THE FORECAST WITH THE LATEST
UPDATE. PREVIOUS DISCUSSION FOLLOWS:
11-3.9 MICRON IMAGERY REVEALS MOSTLY CLEAR NIGHT TIME SKIES
ACROSS NE SC AND SE NC WITH A FEW COASTAL CLOUDS BRUSHING ASHORE
NEAR CAPE FEAR. FAST ANIMATION OF LONG LOOP IR SHOWS SHOWER
OUTFLOW APPEARS TO BE AIDING THE MORE LANDWARD PUSH OF CLOUDS.
KLTX RADAR SHOWING A LINE OF SCATTERED MODERATE AND ISOLATED HEAVY
SHOWERS 50NM OFFSHORE OF THE CAROLINA COASTLINE MOVING TOWARD THE
SW AT 30 KTS. KLTX VAD WIND PROFILE DEPICTS NE WINDS 25-30 KT IN
THE LOWEST FEW THOUSAND FEET OF THE ATMOSPHERE. SATELLITE DERIVED
AND BLENDED PWAT VALUES SHOW A PLUME OF DEEPER MOISTURE WELL
OFFSHORE WITH DRY CONTINENTAL AIR HOLDING ACROSS OUR LAND
ZONES...WITH NE SC SLIGHTLY HIGHER IN COLUMN VAPOR CONTENT. LATEST
SURFACE ANALYSIS SHOWS A HIGH PRES AXIS REMAINED WEDGED NE TO SW
ALONG THE INTERIOR OF THE CAROLINAS.
ALTHOUGH A GRADUAL INLAND MOISTURE FLUX IS ANTICIPATED OVERNIGHT
IT DOES NOT APPEAR A GREAT DEAL OF CLOUD COVER INLAND BEYOND THE
COASTAL INTERIOR. GIVEN THE LOW-LEVEL WINDS AND INCREASING
BOUNDARY LAYER RH...PATCHY STRATUS FORMATION IS POSSIBLE. MORE
LIKELY THAN CLOUDS OFF THE WATER. FOR THE LATE EVENING UPDATE
WILL LEAVE CLEAR TO MOSTLY CLEAR SKY COVER IN PLACE. NO OTHER
CHANGES ARE PLANNED AT THIS TIME. FOG WILL REMAIN INHIBITED FROM
BECOMING SIGNIFICANT DUE TO THE BL WINDS. MINIMUMS SHOULD SETTLE
IN THE MID 40S NEAR THE COAST AND UPPER 30 INLAND.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH MONDAY NIGHT/...
AS OF 330 PM SATURDAY...SURFACE HIGH WILL CONTINUE RIDGING DOWN
THE COAST SUN...MAINTAINING LOW LEVEL NORTHEAST FLOW. MORNING
CLOUD COVER SHOULD BREAK UP BUT BY MID TO LATE AFTERNOON CLOUD
COVER WILL START INCREASING OVER THE AREA...EXPANDING FROM EAST TO
WEST. INCREASED CLOUD WILL BE THE RESULT OF WEAK TROUGH STARTING
TO DEVELOP JUST OFF THE CAROLINA COAST LATER IN THE DAY. PRECIP
CHANCES REMAIN LIMITED WITH DEEPEST MOISTURE HANGING OFFSHORE AND
WEAK RIDGING ALOFT WORKING TO KEEP THE REGION DRY. HIGHS NEAR TO
SLIGHTLY BELOW CLIMO.
CLOUD COVER AND THE PRECIP CHANCES CONTINUE INCREASING SUN NIGHT AS
IMPRESSIVE SHORTWAVE TROUGH MOVES FROM THE MS VALLEY TO THE MID
ATLANTIC STATES. RAINFALL SPREADS ACROSS THE AREA SUN NIGHT AS
ISENTROPIC LIFT INCREASES. LATER SUN NIGHT AND ON MON MORNING
ENHANCEMENT OF THE ACTIVITY IS POSSIBLE AS THE SHORTWAVE AIDS
DIVERGENCE IN SOUTHWEST FLOW ALOFT. COASTAL TROUGH AND ISENTROPIC
LIFT ARE SHIFTED NORTHEAST DURING MON AS MID LEVEL TROUGH MOVES
EAST. IN MOST AREAS PRECIP WILL END AROUND MIDDAY BUT ALONG THE NC
COAST RAIN MAY LINGER INTO LATE AFTERNOON. HIGH PRESSURE BUILDS
OVER THE AREA FOR THE END OF THE PERIOD WITH HEIGHTS/THICKNESS
QUICKLY REBOUNDING IN THE WAKE OF THE 5H TROUGH. CLOUD COVER WILL
HELP KEEP LOWS SUN NIGHT ABOVE CLIMO. HIGHS ON MON WILL END UP
BELOW CLIMO WITH LOWS MON NIGHT NEAR TO SLIGHTLY ABOVE CLIMO.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 330 PM SATURDAY...HIGH PRESSURE WILL BUILD IN ACROSS THE
CAROLINAS AS RIDGE BUILDS IN ALOFT THROUGH MID WEEK. A DEEP W-NW
FLOW OF DRY AIR WILL KEEP CLOUDS AND PCP OUT OF FORECAST THROUGH
MUCH OF THE MID WEEK PERIOD. THE HIGH WILL SHIFT EAST OFF THE COAST
LATE WED INTO THURS WITH A DEEPER S-SW RETURN FLOW SETTING UP.
ANOTHER SHORTWAVE WILL PASS THROUGH THE CAROLINAS IN A VERY
PROGRESSIVE PATTERN LATE WED INTO THURS BUT THIS WILL ONLY PRODUCE
SOME PASSING CLOUDS. A WEAK RIDGE WITH MORE OF AN ZONAL FLOW WILL
PERSIST THURS INTO FRI BEFORE A RIDGE BUILDS UP THE SOUTHEAST COAST
BY THE WEEKEND. NOT LOOKING LIKE MUCH IN THE WAY OF CLOUDS OR PCP
ACROSS THE AREA THROUGH THE WEEK UNTIL NEXT SYSTEM AFFECTS THE
SOUTHEAST OVER THE WEEKEND. TEMPS WILL GENERALLY RUN ABOVE NORMAL
AIDED BY RIDGING ALOFT AND A WESTERLY FLOW THROUGH MID WEEK AND THEN
A MORE SUBSTANTIAL RETURN FLOW HEADING INTO THE WEEKEND.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
AS OF 06Z...VFR CONDITIONS WILL CONTINUE FOR THE NEXT FEW HOURS
WITH NORTHEAST FLOW ACROSS THE TAF SITES. MODELS CONTINUE TO SHOW
LOW-LEVEL MOISTURE INCREASING OVERNIGHT AND THE 00 UTC
EXPERIMENTAL RUN OF THE HRRR IS SHOWING IF STRATUS AND FOG DEVELOPING
OVER ALL TAF SITES EXCEPT KMYR AND KCRE GENERALLY BETWEEN 9 AND 12
UTC BEFORE BREAKING UP AFTER SUNRISE.
EXTENDED AVIATION OUTLOOK...POTENTIAL FOR RESTRICTIONS TO DEVELOP
ON MONDAY WITH LOW CLOUDS AND SHOWERS. OTHERWISE EXPECT VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1230 AM SUNDAY...NO CHANGES TO THE FORECAST WITH THE LATEST
UPDATE. PREVIOUS DISCUSSION FOLLOWS:
LONG DURATION SMALL CRAFT ADVISORY WILL CONTINUE THROUGH SUNDAY
NIGHT. THE PRESSURE GRADIENT WILL REMAIN TIGHT DUE TO A STRONG
AREA OF HIGH PRESSURE RIDGING SOUTHWARD AS IT PUSHES OFFSHORE.
THIS WILL KEEP WINDS FROM THE NE AT 20 TO 25 KT WITH SOME GUSTS TO
30 KT. SEAS WILL RANGE FROM 4 TO 7 FT AND UP TO 8 FT NEAR FRYING
PAN SHOALS.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 330 PM SATURDAY...SMALL CRAFT ADVISORY CONTINUES INTO
SUNDAY NIGHT WITH HIGH RIDGING DOWN THE COAST MAINTAINING ENHANCED
NORTHEAST FLOW. ALTHOUGH GRADIENT STARTS TO RELAX AND WINDS WILL
DROP BELOW SCA THRESHOLDS SEAS TAKE LONGER TO SUBSIDE. MID LEVEL
TROUGH PASSES NORTH OF THE WATERS MON WITH SURFACE FLOW BACKING
FROM NORTHEAST TO NORTHWEST DURING THE DAY. SECONDARY SURGE
DEVELOPS LATE MON INTO MON NIGHT AS HIGH BUILDS IN BUT SURGE DOES
NOT APPEAR TO BE STRONG ENOUGH TO REQUIRE HEADLINES.
LONG TERM /TUESDAY THROUGH THURSDAY/...
AS OF 330 PM SATURDAY...WIND FLOW WILL BE N-NW AS THE LOW PULLS
FARTHER AWAY ON TUESDAY AND HIGH PRESSURE TAKES HOLD AT THE
SURFACE. WINDS AND SEAS WILL BE DIMINISHING THROUGH MID WEEK AS
HIGH PRESSURE SHIFTS EASTWARD. BY LATE WED INTO THURS THE HIGH
WILL SHIFT FARTHER OFF SHORE WITH WINDS BACKING TO THE WEST TO
SOUTHWEST AS RETURN FLOW SETS UP. THEREFORE NW-N WINDS 10 TO 15
KTS EARLY WED WILL LOWER TO LESS THAN 10 KTS THROUGH WED. SEAS UP
TO 3 TO 4 FT EARLY THURS WILL BE DOWN LESS THAN 3 FT HEADING INTO
WED AND WILL SPIKE UP JUST SLIGHTLY WED NIGHT INTO THURS AS WINDS
INCREASE OVERNIGHT WED VERY BRIEFLY AS SHORTWAVE MOVES THROUGH.
OVERALL SEAS WILL BE 3 FT OR LESS WITH A LONGER PERIOD SE-E SWELL
MIXING IN.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 2 AM EST MONDAY FOR AMZ250-252-254-
256.
&&
$$
SYNOPSIS...III
NEAR TERM...REK/RJD
SHORT TERM...III
LONG TERM...RGZ
AVIATION...DRH
MARINE...REK/RJD/III/RGZ
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1132 PM CST SAT DEC 5 2015
.UPDATE...
ISSUED AT 1132 PM CST SAT DEC 5 2015
UPDATED CODING FOR FOG ADV AT THE BOTTOM.
UPDATE ISSUED AT 1126 PM CST SAT DEC 5 2015
COORD WITH WFO MPX...FOG IN THAT ELBOW LAKE-FERGUS FALLS-DETROIT
LAKES AREA IS MORE DENSE AND WILL ISSUE A DENSE FOG ADV FOR THAT
AREA TIL 15Z. THIS IS ON THE BACKEDGE OF THE CLEARING. WILL
MAINTAIN PATCHY FOG MOST OTHER PLACES IN THE SNOW MELT AREA.
WEBCAMS SHOWED QUITE A BIT OF LOW LEVEL MOISTURE WAS LIKELY ADDED
AS SNOW MELT WAS CONSIDERABLE THIS PAST DAY.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 300 PM CST SAT DEC 5 2015
THE MAIN CHALLENGE WILL CONTINUE TO BE TEMPS WITH VERY MILD TEMPS
CONTINUING INTO THE MIDDLE OF NEXT WEEK. MODELS ARE IN GOOD
AGREEMENT WITH LARGER SCALE FEATURES...BUT STRUGGLING WITH LOW
LEVEL TEMPS. THE MAV MOS GUIDANCE HAS THE BEST HANDLE ON TEMPS IN
THE NEAR TERM AT LEAST.
FOR TONIGHT...THERE HAS BEEN MELTING OF SNOW IN THE PAST 24
HOURS...AND DEWPOINTS ARE IN THE LOW/MID 30S OVER THE SNOW FIELD
THIS AFTERNOON. EVEN WITH WESTERLY WINDS IN THE 5 TO 10 MPH RANGE
FOR MUCH OF THE NIGHT...THERE SHOULD BE AT LEAST SOME PATCHY FOG
OVER THE SNOW AREAS. MODELS DO NOT INDICATE TOO MUCH
FOG...ALTHOUGH THE LATEST HRRR IS INDICATING SOME LOWER VSBYS OVER
MN SINCE WINDS HERE MAY BE FAIRLY LIGHT. TEMPS WILL BE WELL ABOVE
NORMAL GENERALLY IN THE LOW/MID 20S.
FOR SUNDAY...TEMPERATURES WILL BE VERY SIMILAR TO TODAY AND
PERHAPS A FEW DEGREES WARMER WITH 925MB TEMPS NEAR +10C BY
AFTERNOON. WE WILL CONTINUE TO GO THE WARMEST OVER THE SNOW FREE
AREAS IN NORTHEAST ND.
ON SUNDAY NIGHT...ANOTHER MILD NIGHT WITH SOUTHERLY WINDS AROUND
10 MPH THAT SHOULD PRECLUDE ANY FOG FORMATION.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 300 PM CST SAT DEC 5 2015
ON MONDAY...925MB TEMPS COOL SOME BUT ARE STILL WELL ABOVE 0C.
THERE SHOULD BE WESTERLY SFC WINDS THAT WILL ONCE AGAIN BOOST
TEMPS TO AROUND 40 PERHAPS EVEN MID 40S FOR SOME WITH MINIMAL SNOW
COVER.
FOR MONDAY NIGHT...EXPECT INCREASING CLOUDS AND WINDS REMAINING
A BIT ELEVATED. THIS SHOULD MEAN A VERY MILD NIGHT WITH OVERNIGHT
LOWS AROUND 30.
FOR TUE...A SHORTWAVE WILL SWING THROUGH THE REGION AND BRING A
LOW CHANCE FOR SOME LIGHT RAIN. THERE COULD BE A BRIEF WINDOW
EARLY TUE MORNING FOR SOME FREEZING RAIN...BUT WITH TEMPS SO MILD
NOT EXPECTING THIS TO BE ANY TYPE OF THREAT SO WILL KEEP IT ALL
LIQUID RAIN FOR NOW. TEMPS SHOULD ONCE AGAIN WARM TO AROUND 40 OR
THE MID 40S FOR ALL AREAS WITH MORE CLOUDS IN THE EAST.
FORECAST STARTING ON WEDNESDAY NIGHT LOOKS A BIT ON THE ACTIVE
SIDE...POTENTIALLY. THE 12Z GFS AND ECMWF BOTH HAVE AN UPPER LOW
BARRELING ALONG THE CANADIAN BORDER EASTWARD ON WEDNESDAY NIGHT. LOW
LEVEL TEMPS ARE ABOVE FREEZING AHEAD OF THIS SYSTEM...THEN DROPPING
BELOW FREEZING. WHICH MEANS RAIN CHANGING TO SNOW POSSIBLY. THE BEST
CHANCE FOR PRECIPITATION WITH THIS SYSTEM WILL BE OVER NORTHWESTERN
MN...WHERE THE ECMWF HAS SIGNIFICANT SNOWFALL FORECASTED. MODELS ARE
TRENDING A LITTLE FURTHER SOUTH AND WETTER WITH THE WED NIGHT/THU
SYSTEM. A SHOT OF COOLER AIR IS THEN COMING FOR THE WEEKEND. THE GFS
HAS A POTENT LOW MOVING NE ACROSS THE REGION FOR SATURDAY...WHILE
THE ECMWF KEEPS IT A BIT FURTHER EAST AND A LITTLE WEAKER. THE ECMWF
HAS TRENDED WESTWARD A BIT WITH THIS ONE...BACK FURTHER WEST INTO
THE RED RIVER VALLEY. SO...A CHANCE FOR PRECIP ON SATURDAY SEEMS
REASONABLE...WITH COOLER TEMPS COMPARED TO THE PREVIOUS WEEK`S
WARMTH.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1126 PM CST SAT DEC 5 2015
BEMIDJI TAF SITE IS ON THE NW EDGE OF LOW CLOUDS AND FOG OVERNIGHT
INTO SUNDAY MORNING. AS SUCH VARIABLE CONDITIONS EXPECTED...BUT
SOME REDUCTION IN CIGS AND/OR VSBYS TO IFR RANGE PSBL. MORE
WIDESPREAD FOG DTL-FFM AREA WITH LOW CLOUDS PKD-ADC.
OTHERWISE...PATCHY FOG WITH LOCAL MVFR VSBYS FARGO AREA AND THEN
INTO NW MN. COULD HAVE SOME AROUND GFK/TVF AS WELL BUT LEFT OUT
FOR NOW. DVL AREA SHOULD REMAIN FOG FREE. ONCE ANY FOG ISSUES ARE
DONE WITH THE REST OF THE PD WILL BE VFR WITH LIGHT SOUTH-
SOUTHWEST WINDS.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...DENSE FOG ADVISORY UNTIL 9 AM CST SUNDAY FOR MNZ027-028-030-031-
040.
&&
$$
UPDATE...RIDDLE
SHORT TERM...DK
LONG TERM...DK/KNUTSVIG
AVIATION...RIDDLE
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1129 PM CST SAT DEC 5 2015
.UPDATE...
ISSUED AT 1126 PM CST SAT DEC 5 2015
COORD WITH WFO MPX...FOG IN THAT ELBOW LAKE-FERGUS FALLS-DETROIT
LAKES AREA IS MORE DENSE AND WILL ISSUE A DENSE FOG ADV FOR THAT
AREA TIL 15Z. THIS IS ON THE BACKEDGE OF THE CLEARING. WILL
MAINTAIN PATCHY FOG MOST OTHER PLACES IN THE SNOW MELT AREA.
WEBCAMS SHOWED QUITE A BIT OF LOW LEVEL MOISTURE WAS LIKELY ADDED
AS SNOW MELT WAS CONSIDERABLE THIS PAST DAY.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 300 PM CST SAT DEC 5 2015
THE MAIN CHALLENGE WILL CONTINUE TO BE TEMPS WITH VERY MILD TEMPS
CONTINUING INTO THE MIDDLE OF NEXT WEEK. MODELS ARE IN GOOD
AGREEMENT WITH LARGER SCALE FEATURES...BUT STRUGGLING WITH LOW
LEVEL TEMPS. THE MAV MOS GUIDANCE HAS THE BEST HANDLE ON TEMPS IN
THE NEAR TERM AT LEAST.
FOR TONIGHT...THERE HAS BEEN MELTING OF SNOW IN THE PAST 24
HOURS...AND DEWPOINTS ARE IN THE LOW/MID 30S OVER THE SNOW FIELD
THIS AFTERNOON. EVEN WITH WESTERLY WINDS IN THE 5 TO 10 MPH RANGE
FOR MUCH OF THE NIGHT...THERE SHOULD BE AT LEAST SOME PATCHY FOG
OVER THE SNOW AREAS. MODELS DO NOT INDICATE TOO MUCH
FOG...ALTHOUGH THE LATEST HRRR IS INDICATING SOME LOWER VSBYS OVER
MN SINCE WINDS HERE MAY BE FAIRLY LIGHT. TEMPS WILL BE WELL ABOVE
NORMAL GENERALLY IN THE LOW/MID 20S.
FOR SUNDAY...TEMPERATURES WILL BE VERY SIMILAR TO TODAY AND
PERHAPS A FEW DEGREES WARMER WITH 925MB TEMPS NEAR +10C BY
AFTERNOON. WE WILL CONTINUE TO GO THE WARMEST OVER THE SNOW FREE
AREAS IN NORTHEAST ND.
ON SUNDAY NIGHT...ANOTHER MILD NIGHT WITH SOUTHERLY WINDS AROUND
10 MPH THAT SHOULD PRECLUDE ANY FOG FORMATION.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 300 PM CST SAT DEC 5 2015
ON MONDAY...925MB TEMPS COOL SOME BUT ARE STILL WELL ABOVE 0C.
THERE SHOULD BE WESTERLY SFC WINDS THAT WILL ONCE AGAIN BOOST
TEMPS TO AROUND 40 PERHAPS EVEN MID 40S FOR SOME WITH MINIMAL SNOW
COVER.
FOR MONDAY NIGHT...EXPECT INCREASING CLOUDS AND WINDS REMAINING
A BIT ELEVATED. THIS SHOULD MEAN A VERY MILD NIGHT WITH OVERNIGHT
LOWS AROUND 30.
FOR TUE...A SHORTWAVE WILL SWING THROUGH THE REGION AND BRING A
LOW CHANCE FOR SOME LIGHT RAIN. THERE COULD BE A BRIEF WINDOW
EARLY TUE MORNING FOR SOME FREEZING RAIN...BUT WITH TEMPS SO MILD
NOT EXPECTING THIS TO BE ANY TYPE OF THREAT SO WILL KEEP IT ALL
LIQUID RAIN FOR NOW. TEMPS SHOULD ONCE AGAIN WARM TO AROUND 40 OR
THE MID 40S FOR ALL AREAS WITH MORE CLOUDS IN THE EAST.
FORECAST STARTING ON WEDNESDAY NIGHT LOOKS A BIT ON THE ACTIVE
SIDE...POTENTIALLY. THE 12Z GFS AND ECMWF BOTH HAVE AN UPPER LOW
BARRELING ALONG THE CANADIAN BORDER EASTWARD ON WEDNESDAY NIGHT. LOW
LEVEL TEMPS ARE ABOVE FREEZING AHEAD OF THIS SYSTEM...THEN DROPPING
BELOW FREEZING. WHICH MEANS RAIN CHANGING TO SNOW POSSIBLY. THE BEST
CHANCE FOR PRECIPITATION WITH THIS SYSTEM WILL BE OVER NORTHWESTERN
MN...WHERE THE ECMWF HAS SIGNIFICANT SNOWFALL FORECASTED. MODELS ARE
TRENDING A LITTLE FURTHER SOUTH AND WETTER WITH THE WED NIGHT/THU
SYSTEM. A SHOT OF COOLER AIR IS THEN COMING FOR THE WEEKEND. THE GFS
HAS A POTENT LOW MOVING NE ACROSS THE REGION FOR SATURDAY...WHILE
THE ECMWF KEEPS IT A BIT FURTHER EAST AND A LITTLE WEAKER. THE ECMWF
HAS TRENDED WESTWARD A BIT WITH THIS ONE...BACK FURTHER WEST INTO
THE RED RIVER VALLEY. SO...A CHANCE FOR PRECIP ON SATURDAY SEEMS
REASONABLE...WITH COOLER TEMPS COMPARED TO THE PREVIOUS WEEK`S
WARMTH.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1126 PM CST SAT DEC 5 2015
BEMIDJI TAF SITE IS ON THE NW EDGE OF LOW CLOUDS AND FOG OVERNIGHT
INTO SUNDAY MORNING. AS SUCH VARIABLE CONDITIONS EXPECTED...BUT
SOME REDUCTION IN CIGS AND/OR VSBYS TO IFR RANGE PSBL. MORE
WIDESPREAD FOG DTL-FFM AREA WITH LOW CLOUDS PKD-ADC.
OTHERWISE...PATCHY FOG WITH LOCAL MVFR VSBYS FARGO AREA AND THEN
INTO NW MN. COULD HAVE SOME AROUND GFK/TVF AS WELL BUT LEFT OUT
FOR NOW. DVL AREA SHOULD REMAIN FOG FREE. ONCE ANY FOG ISSUES ARE
DONE WITH THE REST OF THE PD WILL BE VFR WITH LIGHT SOUTH-
SOUTHWEST WINDS.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...FROST ADVISORY UNTIL 9 AM CST SUNDAY FOR MNZ027-028-030-031-040.
&&
$$
UPDATE...RIDDLE
SHORT TERM...DK
LONG TERM...DK/KNUTSVIG
AVIATION...RIDDLE
AREA FORECAST DISCUSSION
NWS MEDFORD OR
1028 PM PST SAT DEC 5 2015
.UPDATE...JUST SENT AN UPDATE TO EXTEND THE HIGH SURF ADVISORY
ALONG THE COAST UNTIL 4 AM SUNDAY. SEAS AND CORRESPONDING COASTAL
SURF WILL LIKELY REMAIN HIGH UNTIL WINDS ASSOCIATED WITH THE FRONT
DIE DOWN EARLY TOMORROW MORNING. -WRIGHT
&&
.AVIATION...FOR THE 06/06Z TAF CYCLE...WIND SPEED SHEAR WILL BE
THE MAIN CONCERN TONIGHT AT THE COAST, INCLUDING NORTH BEND AND
ROSEBURG. WIND SHEAR WAS ALSO ADDED TO THE KMFR TAF FOR TONIGHT.
WHILE HIGHER WIND SPEEDS AT THE SURFACE ARE LIMITING SPEED SHEAR,
A DIRECTIONAL COMPONENT IS EXPECTED TO DEVELOP AS SOUTH-SOUTHWEST
WINDS ALOFT INCREASE TONIGHT. VFR CEILINGS WILL GRADUALLY LOWER
TONIGHT WITH RAIN AND MVFR CIGS SPREADING INLAND AND MOUNTAIN
OBSCURATION INCREASING. SOME THE WORST CONDITIONS ARE EXPECTED IN
THE MOUNT SHASTA CITY AREA WHERE UPSLOPING WINDS AND SNOWFALL
TONIGHT WILL CREATE VLIFR CONDITIONS. -WRIGHT
&&
.PREV DISCUSSION... /ISSUED 822 PM PST SAT DEC 5 2015/
DISCUSSION...NO CHANGES TO ANY OF THE HEADLINES THIS EVENING. AN
UPDATE WAS JUST SENT, MAINLY TO ADD ISOLATED THUNDERSTORMS TO THE
WATERS AND COAST TONIGHT. THERE HAVE BEEN SEVERAL DOZEN STRIKES
WITH THE UPPER TROUGH AXIS THIS EVENING, AND MODELS INDICATE THIS
INSTABILITY WILL PERSIST AS THE TROUGH SWINGS INTO THE COAST
OVERNIGHT.
WINDS CONTINUE TO RAMP UP THIS EVENING AS THE FRONT APPROACHES.
WE ARE ALREADY GETTING GUSTS NEAR 70 MPH AT SQUAW PEAK, WELL INTO
THE 50S ALONG THE COAST, AND AS HIGH AS 55 MPH AT WEED. BUOY 46015
(15 MILES OFF CAPE BLANCO) IS GUSTING WELL INTO STORM FORCE, AND
SO FAR, WE`VE HAD GUSTS TO 32 MPH AT THE MEDFORD AIRPORT. THE
MYRIAD WIND WARNINGS AND ADVISORIES COVER ALL THIS WELL.
THE FRONT WILL MOVE THROUGH OUR AREA TONIGHT WITH WINDS DECREASING
BEHIND IT. EVERYBODY OUGHT TO SEE SOME RAIN WITH THIS FRONT, BUT
LATEST NAM AND RAP GUIDANCE WOULD INDICATE WE GET LITTLE TO NONE
IN MEDFORD. I THINK THIS IS DUE TO THE FACT THAT ANOTHER FRONT IS
RIGHT ON THE HEELS OF THIS ONE, AND AS A RESULT, THE WINDS NEVER
REALLY SWING AROUND TO WESTERLY BEHIND THE FIRST FRONT. HOWEVER, I
SEE NO REASON TO REMOVE RAIN ENTIRELY FROM MEDFORD BASED ON THIS,
BUT WITH DOWNSLOPING, IT WILL TAKE A WHILE, AND IT WON`T BE A BIG
DELUGE IN THE ROGUE VALLEY ONCE IT DOES GET HERE. -WRIGHT
MARINE...UPDATED 300 PM PST SATURDAY 5 DEC 2015...THE LATEST ASCAT
PASS AT 19Z SHOED WINDS NEAR 42 KTS OVER MOST OF THE OUTER WATERS.
THE LATEST OBSERVATION AT BUOY 15 SHOWS WIND GUST NEAR 45 KTS WITH A
PEAK GUST TO 47 KTS. CURRENT HEADLINES LOOK GOOD AND NO CHANGES WILL
BE NEEDED. THE MAIN CONCERN INTO TONIGHT WILL BE STRONG WINDS VERY
STEEP SEAS. A COLD FRONT WILL MOVE INTO THE WATERS LATE TONIGHT,THEN
MOVE INLAND EARLY SUNDAY MORNING. A RELATIVE BREAK IN THE ACTION IS
EXPECTED SUNDAY MORNING WITH WINDS AND SEAS BRIEFLY DIMINISHING,
THEN ANOTHER STRONG WARM FRONT WILL ARRIVE SUNDAY AFTERNOON AND
WE`LL HAVE ANOTHER ROUND OF GALES AND VERY LARGE LONG PERIOD
WESTERLY SWELL. A SERIES OF FRONTAL SYSTEMS WILL AFFECT THE WATERS
FOR MOST OF NEXT WEEK. -PETRUCELLI
PREV DISCUSSION... /ISSUED 312 PM PST SAT DEC 5 2015/
SHORT TERM...A SERIES OF STORM SYSTEMS WILL TAKE AIM AT THE
PACIFIC NORTHWEST OVER THE NEXT SEVERAL DAYS. THIS IS DUE TO A
VERY STRONG AND PERSISTENT CENTRAL PACIFIC JET STREAM, WHICH WILL
REACH SPEEDS EXCEEDING 160KT BY EARLY NEXT WEEK. AT TIMES OVER THE
NEXT FEW DAYS, WE`LL SEE AN EXTENSION OF THE JET INTO THE PACIFIC
NORTHWEST. THE FIRST SYSTEM ON THE NOSE OF THE JET...A STRONG
COLD FRONT OFFSHORE THIS AFTERNOON...IS BRINGING STRONG GALE TO
STORM FORCE WINDS TO THE COASTAL WATERS ALONG WITH VERY HIGH SEAS.
A HIGH SURF ADVISORY (CFWMFR) IS OUT UNTIL LATE THIS EVENING
SOUTH OF CAPE BLANCO AS THE SOUTH WINDS PILE WATER UP ALONG
SOUTH-FACING PORTS, BEACHES AND JETTIES. THE FRONT WILL MOVE
ONSHORE LATER TONIGHT, THEN INLAND ON SUNDAY. THE MAIN INLAND
WEATHER IMPACT FROM THE FRONT WILL BE WIND. THIS SYSTEM WON`T BE
QUITE AS WINDY AS THE ONE A COUPLE OF DAYS AGO, BUT STILL WARNING-
WORTHY IN MANY AREAS. WINDS ARE BEGINNING TO SURFACE HERE IN THE
ROGUE VALLEY AND EXPECT SOME GUSTS OF 35 TO 40 MPH OVERNIGHT INTO
SUNDAY MORNING...ESPECIALLY AT THE SOUTH END OF THE VALLEY.
NUMEROUS WIND HEADLINES ARE IN EFFECT, SO PLEASE SEE NPWMFR FOR
MORE SPECIFIC DETAILS.
A CLOSER LOOK AT THE MODEL DATA TODAY SUGGESTED ADVISORY LEVEL
SNOW POTENTIAL ABOVE 3500 FEET IN PORTIONS OF SISKIYOU COUNTY
OVERNIGHT INTO SUNDAY MORNING. THINK MOST OF THE PRECIPITATION
FALLS AS RAIN IN MOUNT SHASTA CITY, BUT IT MAY MIX WITH AND CHANGE
TO SNOW FOR A WHILE SUNDAY MORNING. THERE IS A BETTER CHANCE FOR
ACCUMULATING SNOW UP ON BLACK BUTTE/SNOWMAN`S SUMMITS AND SOME OF
THE OTHER PASSES IN WESTERN SISKIYOU COUNTY, SO HAVE ISSUED A
WINTER WEATHER ADVISORY THERE (WSWMFR).
RAINFALL FROM THIS SYSTEM WILL BE HEAVIEST ALONG THE SOUTHWEST
COAST...THE ADJACENT COAST RANGES...AND EXTREME WESTERN SISKIYOU
COUNTY WHERE 1-3 INCHES IS LIKELY. WEST SIDE VALLEY RAIN AMOUNTS
WILL BE IN THE 0.20-0.40 OF AN INCH RANGE.
THERE WILL BE A BRIEF BREAK BETWEEN SYSTEMS SUNDAY AFTERNOON AND
EVENING, BUT A WARM FRONT WILL LIFT NORTH OF THE AREA SUNDAY NIGHT
INTO MONDAY. THIS WILL BRING ANOTHER ROUND OF RAIN AND WIND TO THE
COAST WITH GUSTY WINDS OVER PORTIONS OF THE INTERIOR. HOWEVER,
SNOW IMPACTS WILL BE NEGLIGIBLE SINCE SNOW LEVELS ARE EXPECTED TO
BE ABOVE 8000 FEET BY MONDAY AFTERNOON.
YET ANOTHER SYSTEM WILL ARRIVE LATER TUESDAY AND TUESDAY NIGHT.
WITH ALL THE RAIN EXPECTED WITH THESE SYSTEMS, A FLOOD POTENTIAL
OUTLOOK FOR RAPID RISES ON STREAMS, CREEKS AND RIVERS (ESFMFR) WAS
ISSUED FOR PORTIONS OF CURRY, COOS AND JOSEPHINE COUNTIES. MODEL
DEPICTIONS SHOW SOME PLACES ALONG THE COAST RECEIVING MORE THAN 10
INCHES OF RAINFALL THROUGH LATE NEXT WEEK. SPILDE
LONG TERM...WEDNESDAY THROUGH SATURDAY...I WILL FOCUS ON SNOW
LEVELS AND EXPECTED IMPACTS TO SNOWPACK DURING THE EXTENDED. THIS
COULD BE THE BEGINNING TO A SIGNIFICANT PERIOD OF BUILDING SNOWPACK
OVER THE REGION...WHICH HAS BEEN DEALING WITH A SNOW DROUGHT THE
PAST SEVERAL YEARS.
IT`S BEEN THREE YEARS SINCE 2 FEET OF SNOW DEPTH HAS BEEN MEASURED
AT CRATER LAKE NATIONAL PARK ON THIS DATE. THE LAST TIME THAT
OCCURRED WAS DEC 5, 2012. WEDNESDAY WILL FEATURE THE TAIL END OF
ABOUT A TWO-DAY PERIOD OF HIGH SNOW LEVELS...ABOVE 7000 FEET. AN
UPPER TROUGH PATTERN DEVELOPS OVER THE NORTHEAST PACIFIC OCEAN ON
WEDNESDAY AND 850MB TEMPERATURES...A RELIABLE INDICATOR OF HOW
WARM/COLD THE AIR MASS IS...BEGIN TO DROP. THOUGH SPECIFIC DETAILS
OF THE WEATHER PATTERN LATE IN THE WEEK DIFFER...THE GEFS MEMBERS
AGREE ON A COOLER REGIME AND LOWERING SNOW LEVELS. THE LATEST
OPERATIONAL GFS SHOWS A 48-HOUR PRECIPITATION TOTAL OF 2 INCHES FROM
WEDNESDAY AFTERNOON THROUGH FRIDAY AFTERNOON...WHICH COULD TRANSLATE
TO A FEW FEET OF SNOW ABOVE 6000 FEET. THEN...WITH THE CLIMATE
PREDICTION CENTER SHOWING ENHANCED CHANCES FOR ABOVE NORMAL
PRECIPITATION AND BELOW NORMAL TEMPERATURES ON WEEK 2...THIS
SNOWPACK COULD BUILD FURTHER.
SHIFTING GEARS FROM THE SNOWPACK SITUATION TO THE DETAILS OF THE
EXTENDED...WEDNESDAY FEATURES A COLD FRONT SWINGING
THROUGH...DROPPING SNOW LEVELS AND BRINGING MODERATE TO HEAVY
PRECIPITATION TO THE COAST AND CASCADES. OPERATIONAL MODEL AGREEMENT
IS GOOD ON THIS EVENT. DETAILS ARE A LITTLE MORE FUZZY ON THURSDAY
BUT THE IDEA OF COLD TROUGHING AND PLENTY OF SHOWERS...WITH UPSLOPE
ENHANCEMENT OVER THE CASCADES...IS AGREED UPON BY THE EC AND GFS.
SNOW LEVELS ON THURSDAY ARE EXPECTED TO BE BELOW 5000 FEET. A
RELATIVE BREAK IN PRECIPITATION IS EXPECTED ON FRIDAY BUT MORE
PRECIPITATION IS NOT FAR BEHIND AS THE WEATHER PATTERN CONTINUES TO
BE ACTIVE.
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...HIGH WIND WARNING UNTIL 1 PM PST SUNDAY FOR ORZ030-031.
HIGH WIND WATCH FROM MONDAY MORNING THROUGH MONDAY EVENING FOR
ORZ030-031.
HIGH WIND WARNING UNTIL 4 AM PST SUNDAY FOR ORZ021-022.
HIGH SURF ADVISORY UNTIL 4 AM PST SUNDAY FOR ORZ021-022.
HIGH WIND WATCH FROM SUNDAY EVENING THROUGH MONDAY MORNING FOR
ORZ021-022.
WIND ADVISORY FROM 4 AM TO 1 PM PST SUNDAY FOR ORZ023>026.
WIND ADVISORY UNTIL 1 PM PST SUNDAY FOR ORZ029.
CA...HIGH WIND WARNING UNTIL 1 PM PST SUNDAY FOR CAZ085.
HIGH WIND WATCH FROM MONDAY MORNING THROUGH MONDAY EVENING FOR
CAZ085.
WINTER WEATHER ADVISORY UNTIL 10 AM PST SUNDAY ABOVE 3500 FEET
FOR FOR CAZ080-082.
WIND ADVISORY UNTIL 1 PM PST SUNDAY FOR CAZ084.
HIGH WIND WARNING UNTIL 1 PM PST SUNDAY FOR CAZ081-082.
PACIFIC COASTAL WATERS...GALE WATCH FROM SUNDAY AFTERNOON THROUGH
MONDAY AFTERNOON FOR PZZ350-356-370-376.
SMALL CRAFT ADVISORY UNTIL 4 AM PST SUNDAY FOR PZZ356.
STORM WARNING UNTIL 4 AM PST SUNDAY FOR PZZ350-356-370-376.
HAZARDOUS SEAS WATCH FROM SUNDAY AFTERNOON THROUGH MONDAY
AFTERNOON FOR PZZ350-356-376.
GALE WARNING UNTIL 4 AM PST SUNDAY FOR PZZ350-356-370-376.
$$
AREA FORECAST DISCUSSION
NWS MEDFORD OR
822 PM PST SAT DEC 5 2015
.DISCUSSION...NO CHANGES TO ANY OF THE HEADLINES THIS EVENING. AN
UPDATE WAS JUST SENT, MAINLY TO ADD ISOLATED THUNDERSTORMS TO THE
WATERS AND COAST TONIGHT. THERE HAVE BEEN SEVERAL DOZEN STRIKES
WITH THE UPPER TROUGH AXIS THIS EVENING, AND MODELS INDICATE THIS
INSTABILITY WILL PERSIST AS THE TROUGH SWINGS INTO THE COAST
OVERNIGHT.
WINDS CONTINUE TO RAMP UP THIS EVENING AS THE FRONT APPROACHES.
WE ARE ALREADY GETTING GUSTS NEAR 70 MPH AT SQUAW PEAK, WELL INTO
THE 50S ALONG THE COAST, AND AS HIGH AS 55 MPH AT WEED. BUOY 46015
(15 MILES OFF CAPE BLANCO) IS GUSTING WELL INTO STORM FORCE, AND
SO FAR, WE`VE HAD GUSTS TO 32 MPH AT THE MEDFORD AIRPORT. THE
MYRIAD WIND WARNINGS AND ADVISORIES COVER ALL THIS WELL.
THE FRONT WILL MOVE THROUGH OUR AREA TONIGHT WITH WINDS DECREASING
BEHIND IT. EVERYBODY OUGHT TO SEE SOME RAIN WITH THIS FRONT, BUT
LATEST NAM AND RAP GUIDANCE WOULD INDICATE WE GET LITTLE TO NONE
IN MEDFORD. I THINK THIS IS DUE TO THE FACT THAT ANOTHER FRONT IS
RIGHT ON THE HEELS OF THIS ONE, AND AS A RESULT, THE WINDS NEVER
REALLY SWING AROUND TO WESTERLY BEHIND THE FIRST FRONT. HOWEVER, I
SEE NO REASON TO REMOVE RAIN ENTIRELY FROM MEDFORD BASED ON THIS,
BUT WITH DOWNSLOPING, IT WILL TAKE A WHILE, AND IT WON`T BE A BIG
DELUGE IN THE ROGUE VALLEY ONCE IT DOES GET HERE. -WRIGHT
&&
.AVIATION...FOR THE 06/00Z TAF CYCLE...WIND SPEED SHEAR WILL BE
THE MAIN CONCERN TONIGHT AT THE COAST, INCLUDING NORTH BEND AND
ROSEBURG. THE STRONGEST WINDS ARE EXPECTED OVER THE HIGHEST
TERRAIN...AT THE COAST...IN THE SHASTA VALLEY...AND AREAS EAST OF
THE CASCADES. VFR CEILINGS WILL GRADUALLY LOWER THROUGH THIS
EVENING WITH RAIN DEVELOPING AT THE COAST THIS EVENING THEN
SPREADING INLAND TONIGHT WITH AREAS OF MVFR CIGS AND MOUNTAIN
OBSCURATION DEVELOPING.
SOME THE WORST CONDITIONS ARE EXPECTED IN THE MOUNT SHASTA CITY
AREA WHERE UPSLOPING WINDS AND SNOWFALL TONIGHT WILL CREATE
VLIFR CONDITIONS. -PETRUCELLI
&&
.MARINE...UPDATED 300 PM PST SATURDAY 5 DEC 2015...THE LATEST ASCAT
PASS AT 19Z SHOED WINDS NEAR 42 KTS OVER MOST OF THE OUTER WATERS.
THE LATEST OBSERVATION AT BUOY 15 SHOWS WIND GUST NEAR 45 KTS WITH A
PEAK GUST TO 47 KTS. CURRENT HEADLINES LOOK GOOD AND NO CHANGES WILL
BE NEEDED. THE MAIN CONCERN INTO TONIGHT WILL BE STRONG WINDS VERY
STEEP SEAS. A COLD FRONT WILL MOVE INTO THE WATERS LATE TONIGHT,THEN
MOVE INLAND EARLY SUNDAY MORNING. A RELATIVE BREAK IN THE ACTION IS
EXPECTED SUNDAY MORNING WITH WINDS AND SEAS BRIEFLY DIMINISHING,
THEN ANOTHER STRONG WARM FRONT WILL ARRIVE SUNDAY AFTERNOON AND
WE`LL HAVE ANOTHER ROUND OF GALES AND VERY LARGE LONG PERIOD
WESTERLY SWELL. A SERIES OF FRONTAL SYSTEMS WILL AFFECT THE WATERS
FOR MOST OF NEXT WEEK. -PETRUCELLI
&&
.PREV DISCUSSION... /ISSUED 312 PM PST SAT DEC 5 2015/
SHORT TERM...A SERIES OF STORM SYSTEMS WILL TAKE AIM AT THE
PACIFIC NORTHWEST OVER THE NEXT SEVERAL DAYS. THIS IS DUE TO A
VERY STRONG AND PERSISTENT CENTRAL PACIFIC JET STREAM, WHICH WILL
REACH SPEEDS EXCEEDING 160KT BY EARLY NEXT WEEK. AT TIMES OVER THE
NEXT FEW DAYS, WE`LL SEE AN EXTENSION OF THE JET INTO THE PACIFIC
NORTHWEST. THE FIRST SYSTEM ON THE NOSE OF THE JET...A STRONG
COLD FRONT OFFSHORE THIS AFTERNOON...IS BRINGING STRONG GALE TO
STORM FORCE WINDS TO THE COASTAL WATERS ALONG WITH VERY HIGH SEAS.
A HIGH SURF ADVISORY (CFWMFR) IS OUT UNTIL LATE THIS EVENING
SOUTH OF CAPE BLANCO AS THE SOUTH WINDS PILE WATER UP ALONG
SOUTH-FACING PORTS, BEACHES AND JETTIES. THE FRONT WILL MOVE
ONSHORE LATER TONIGHT, THEN INLAND ON SUNDAY. THE MAIN INLAND
WEATHER IMPACT FROM THE FRONT WILL BE WIND. THIS SYSTEM WON`T BE
QUITE AS WINDY AS THE ONE A COUPLE OF DAYS AGO, BUT STILL WARNING-
WORTHY IN MANY AREAS. WINDS ARE BEGINNING TO SURFACE HERE IN THE
ROGUE VALLEY AND EXPECT SOME GUSTS OF 35 TO 40 MPH OVERNIGHT INTO
SUNDAY MORNING...ESPECIALLY AT THE SOUTH END OF THE VALLEY.
NUMEROUS WIND HEADLINES ARE IN EFFECT, SO PLEASE SEE NPWMFR FOR
MORE SPECIFIC DETAILS.
A CLOSER LOOK AT THE MODEL DATA TODAY SUGGESTED ADVISORY LEVEL
SNOW POTENTIAL ABOVE 3500 FEET IN PORTIONS OF SISKIYOU COUNTY
OVERNIGHT INTO SUNDAY MORNING. THINK MOST OF THE PRECIPITATION
FALLS AS RAIN IN MOUNT SHASTA CITY, BUT IT MAY MIX WITH AND CHANGE
TO SNOW FOR A WHILE SUNDAY MORNING. THERE IS A BETTER CHANCE FOR
ACCUMULATING SNOW UP ON BLACK BUTTE/SNOWMAN`S SUMMITS AND SOME OF
THE OTHER PASSES IN WESTERN SISKIYOU COUNTY, SO HAVE ISSUED A
WINTER WEATHER ADVISORY THERE (WSWMFR).
RAINFALL FROM THIS SYSTEM WILL BE HEAVIEST ALONG THE SOUTHWEST
COAST...THE ADJACENT COAST RANGES...AND EXTREME WESTERN SISKIYOU
COUNTY WHERE 1-3 INCHES IS LIKELY. WEST SIDE VALLEY RAIN AMOUNTS
WILL BE IN THE 0.20-0.40 OF AN INCH RANGE.
THERE WILL BE A BRIEF BREAK BETWEEN SYSTEMS SUNDAY AFTERNOON AND
EVENING, BUT A WARM FRONT WILL LIFT NORTH OF THE AREA SUNDAY NIGHT
INTO MONDAY. THIS WILL BRING ANOTHER ROUND OF RAIN AND WIND TO THE
COAST WITH GUSTY WINDS OVER PORTIONS OF THE INTERIOR. HOWEVER,
SNOW IMPACTS WILL BE NEGLIGIBLE SINCE SNOW LEVELS ARE EXPECTED TO
BE ABOVE 8000 FEET BY MONDAY AFTERNOON.
YET ANOTHER SYSTEM WILL ARRIVE LATER TUESDAY AND TUESDAY NIGHT.
WITH ALL THE RAIN EXPECTED WITH THESE SYSTEMS, A FLOOD POTENTIAL
OUTLOOK FOR RAPID RISES ON STREAMS, CREEKS AND RIVERS (ESFMFR) WAS
ISSUED FOR PORTIONS OF CURRY, COOS AND JOSEPHINE COUNTIES. MODEL
DEPICTIONS SHOW SOME PLACES ALONG THE COAST RECEIVING MORE THAN 10
INCHES OF RAINFALL THROUGH LATE NEXT WEEK. SPILDE
LONG TERM...WEDNESDAY THROUGH SATURDAY...I WILL FOCUS ON SNOW
LEVELS AND EXPECTED IMPACTS TO SNOWPACK DURING THE EXTENDED. THIS
COULD BE THE BEGINNING TO A SIGNIFICANT PERIOD OF BUILDING SNOWPACK
OVER THE REGION...WHICH HAS BEEN DEALING WITH A SNOW DROUGHT THE
PAST SEVERAL YEARS.
IT`S BEEN THREE YEARS SINCE 2 FEET OF SNOW DEPTH HAS BEEN MEASURED
AT CRATER LAKE NATIONAL PARK ON THIS DATE. THE LAST TIME THAT
OCCURRED WAS DEC 5, 2012. WEDNESDAY WILL FEATURE THE TAIL END OF
ABOUT A TWO-DAY PERIOD OF HIGH SNOW LEVELS...ABOVE 7000 FEET. AN
UPPER TROUGH PATTERN DEVELOPS OVER THE NORTHEAST PACIFIC OCEAN ON
WEDNESDAY AND 850MB TEMPERATURES...A RELIABLE INDICATOR OF HOW
WARM/COLD THE AIR MASS IS...BEGIN TO DROP. THOUGH SPECIFIC DETAILS
OF THE WEATHER PATTERN LATE IN THE WEEK DIFFER...THE GEFS MEMBERS
AGREE ON A COOLER REGIME AND LOWERING SNOW LEVELS. THE LATEST
OPERATIONAL GFS SHOWS A 48-HOUR PRECIPITATION TOTAL OF 2 INCHES FROM
WEDNESDAY AFTERNOON THROUGH FRIDAY AFTERNOON...WHICH COULD TRANSLATE
TO A FEW FEET OF SNOW ABOVE 6000 FEET. THEN...WITH THE CLIMATE
PREDICTION CENTER SHOWING ENHANCED CHANCES FOR ABOVE NORMAL
PRECIPITATION AND BELOW NORMAL TEMPERATURES ON WEEK 2...THIS
SNOWPACK COULD BUILD FURTHER.
SHIFTING GEARS FROM THE SNOWPACK SITUATION TO THE DETAILS OF THE
EXTENDED...WEDNESDAY FEATURES A COLD FRONT SWINGING
THROUGH...DROPPING SNOW LEVELS AND BRINGING MODERATE TO HEAVY
PRECIPITATION TO THE COAST AND CASCADES. OPERATIONAL MODEL AGREEMENT
IS GOOD ON THIS EVENT. DETAILS ARE A LITTLE MORE FUZZY ON THURSDAY
BUT THE IDEA OF COLD TROUGHING AND PLENTY OF SHOWERS...WITH UPSLOPE
ENHANCEMENT OVER THE CASCADES...IS AGREED UPON BY THE EC AND GFS.
SNOW LEVELS ON THURSDAY ARE EXPECTED TO BE BELOW 5000 FEET. A
RELATIVE BREAK IN PRECIPITATION IS EXPECTED ON FRIDAY BUT MORE
PRECIPITATION IS NOT FAR BEHIND AS THE WEATHER PATTERN CONTINUES TO
BE ACTIVE.
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...HIGH WIND WARNING UNTIL 1 PM PST SUNDAY FOR ORZ030-031.
HIGH WIND WATCH FROM MONDAY MORNING THROUGH MONDAY EVENING FOR
ORZ030-031.
HIGH WIND WARNING UNTIL 4 AM PST SUNDAY FOR ORZ021-022.
HIGH SURF ADVISORY UNTIL 11 PM PST THIS EVENING FOR ORZ021-022.
HIGH WIND WATCH FROM SUNDAY EVENING THROUGH MONDAY MORNING FOR
ORZ021-022.
WIND ADVISORY FROM 4 AM TO 1 PM PST SUNDAY FOR ORZ023>026.
WIND ADVISORY UNTIL 1 PM PST SUNDAY FOR ORZ029.
CA...HIGH WIND WARNING UNTIL 1 PM PST SUNDAY FOR CAZ085.
HIGH WIND WATCH FROM MONDAY MORNING THROUGH MONDAY EVENING FOR
CAZ085.
WINTER WEATHER ADVISORY UNTIL 10 AM PST SUNDAY ABOVE 3500 FEET
FOR FOR CAZ080-082.
WIND ADVISORY UNTIL 1 PM PST SUNDAY FOR CAZ084.
HIGH WIND WARNING UNTIL 1 PM PST SUNDAY FOR CAZ081-082.
PACIFIC COASTAL WATERS...GALE WATCH FROM SUNDAY AFTERNOON THROUGH
MONDAY AFTERNOON FOR PZZ350-356-370-376.
SMALL CRAFT ADVISORY UNTIL 4 AM PST SUNDAY FOR PZZ356.
STORM WARNING UNTIL 4 AM PST SUNDAY FOR PZZ350-356-370-376.
HAZARDOUS SEAS WATCH FROM SUNDAY AFTERNOON THROUGH MONDAY
AFTERNOON FOR PZZ350-356-376.
GALE WARNING UNTIL 4 AM PST SUNDAY FOR PZZ350-356-370-376.
$$
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
347 AM CST SUN DEC 6 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 346 AM CST SUN DEC 6 2015
LOW CONFIDENCE TODAY IN TERMS OF SKY COVER AND TEMPERATURES.
CURRENTLY...TROUGH MOVING THROUGH THE AREA WITH FAIRLY DENSE AND
WIDESPREAD FOG AHEAD OF THE TROUGH. BEHIND THE TROUGH...PATCHY FOG
PERSISTS AND WITH WEAK WINDS AND STOUT INVERSION REMAINING ACROSS
THE AREA...QUESTIONS REMAIN AS TO HOW QUICK THE FOG WILL BURN
OFF...IF AT ALL. BOTH THE HRRR AND RAP KEEP FOG AROUND FOR THE
BETTER PART OF THE DAY...AND EXPAND IT ACROSS THE REGION TONIGHT.
HAVE SIDED WITH CONS SHORT SOLUTION WHICH HAS THE FOG GRADUALLY
BURNING OFF THROUGH THE LATE MORNING HOURS. HAVE SIDED WITH COOLER
GUIDANCE FOR TODAY WITH LOWER SUN ANGLE...WEAK WINDS AND POTENTIAL
STRATUS/FOG ISSUES...HOWEVER...IF FOG IS ABLE TO CLEAR...DAY SHIFT
WILL LIKELY NEED TO RAISE HIGHS 3-5 DEGREES.
FOG POTENTIAL CONTINUES INTO TONIGHT AS SURFACE RIDGE MOVES ACROSS
THE AREA. EXPECT TEMPERATURES TO RISE AFTER MIDNIGHT AS STOUT
SOUTH/SOUTHWEST FLOW INCREASES AHEAD OF A WEAK TROUGH PASSING
THROUGH THE REGION MONDAY MORNING.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 346 AM CST SUN DEC 6 2015
MONDAY MORNING SHOULD START OUT VERY MILD AS A SOUTHERLY BREEZE
BRINGS TEMPERATURES UP QUICKLY. THE GRADIENT SLACKENS JUST A TOUCH
AND WINDS BECOME MORE WESTERLY. WITH DEEPER MIXING POTENTIAL AND A
CONTINUOUSLY DECREASING SNOW COVER HAVE OPTED TO KEEP HIGHS SIMILAR
TO PREVIOUS FORECAST...MAINLY MID 40S TO AROUND 50.
MONDAY NIGHT INTO TUESDAY WILL SEE THIS WESTERLY INFLUENCE CONTINUE
SO VERY MILD LOWS IN THE 20S TO LOWER 30S AND WENT AHEAD AND RAISED
HIGHS A BIT AS SNOW COVER WILL BE GREATLY DIMINISHED BY TUESDAY.
HAVE HIGHS FROM THE MID 40S IN THE BIG SIOUX RIVER VALLEY TO THE
LOWER 50S ALONG THE MISSOURI RIVER CORRIDOR. COULD EVEN GET CLOSER
TO 50 ALONG AND EAST OF THE BUFFALO RIDGE WITH POTENTIAL FOR
ENHANCED MIXING AND LESS SNOW COVER.
IN THE OUTER PERIODS(WEDNESDAY THROUGH SATURDAY)...FAST WESTERLY
FLOW TRANSITIONS TO DEEPER SOUTHERLY FLOW AS A TROUGH OF LOW
PRESSURE DEEPENS OVER THE ROCKIES AND MOVES ONTO THE PLAINS FRIDAY
NIGHT INTO SATURDAY. A RELATIVELY STRONG UPPER LEVEL WAVE WILL MOVE
THROUGH WEDNESDAY NIGHT INTO THURSDAY BUT THE STRONGER FORCING...AND
THUS BETTER CHANCES FOR PRECIPITATION...LOOK TO REMAIN TO THE NORTH
OF THE AREA. PRECIPITATION CHANCES BEGIN TO INCREASE FRIDAY NIGHT
INTO SATURDAY AS THE TROUGH MOVES ONTO THE PLAINS BUT THE MODELS ALL
OVER THE PLACE ON PLACEMENT SO CONFIDENCE ON JUST WHAT WILL HAPPEN
STILL A LITTLE LOW. WILL SIDE A LITTLE MORE CLOSELY TO THE ECMWF
WITH SOME WEIGHTING FROM THE GFS WHILE MOSTLY IGNORING THE GEM. THE
GEM SEEMS A BIT TOO AGGRESSIVE WITH THE WARM SECTOR FRIDAY INTO
SATURDAY...BUT WILL WATCH TRENDS AS THIS PATTERN NOT IMPOSSIBLE BUT
A LITTLE OUT OF SEASON WITH LITTLE TO NO HUDSON BAY LOW INFLUENCE
AND SUGGESTING MUCH MORE RIDGING WHICH IS PRETTY FAR NORTH FOR THIS
TIME OF YEAR. TEMPERATURES WELL ABOVE NORMAL WEDNESDAY AND
THURSDAY...STILL ABOVE NORMAL BUT NOT BY QUITE SO MUCH FRIDAY THEN
CLOSER TO NORMAL BY THE WEEKEND.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1112 PM CST SAT DEC 5 2015
MVFR VISIBILITY IN FOG HAS DEVELOPED IN THE WAKE OF DEPARTING MVFR
STRATUS...WITH AN AREA OF IFR-LIFR VISIBILITY ALONG AND JUST EAST
OF I-29 CORRIDOR. EVOLUTION OF FOG IS UNCERTAIN...BUT SIGNS THAT
IMPROVEMENT FROM LOWEST VISIBILITY WILL MOVE EAST WITH A WEAK
SURFACE BOUNDARY THROUGH 09Z. WITH ABUNDANT SNOWMELT MOISTURE
ADDED TO THE BOUNDARY LAYER...COMBINED WITH RELATIVELY LIGHT WINDS
AS SURFACE RIDGE APPROACHES LATE TONIGHT...COULD SEE FURTHER FOG
DEVELOPMENT AS FAR WEST AS THE JAMES VALLEY...AND WILL CARRY SOME
MVFR-IFR VISIBILITY FOR ALL LOCATIONS INTO EARLY SUNDAY MORNING.
EXPECT ANY FOG WOULD CLEAR BY 15Z-16Z...FOLLOWED BY VFR CONDITIONS
THROUGH THE REMAINDER OF THE TAF PERIOD.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
SHORT TERM...
LONG TERM...08
AVIATION...JH
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
419 AM PST SUN DEC 6 2015
.SYNOPSIS...RAIN WILL SPREAD ACROSS MUCH OF THE SAN FRANCISCO BAY
AREA THIS MORNING. RAINFALL AMOUNTS WILL MOSTLY BE LIGHT. DRY AND
MILD WEATHER IS FORECAST FROM LATE TODAY THROUGH TUESDAY NIGHT.
THE NEXT PACIFIC WEATHER SYSTEM WILL WILL LIKELY BRING HEAVIER AND
MORE WIDESPREAD RAIN TO THE REGION FROM WEDNESDAY THROUGH THURSDAY
NIGHT. SHOWERS MAY LINGER INTO FRIDAY. ANOTHER SYSTEM MAY IMPACT
THE REGION NEXT WEEKEND.
&&
.DISCUSSION...AS OF 3:25 AM PST SUNDAY...RAIN BEGAN TO SPREAD
INTO THE NORTH BAY SHORTLY AFTER MIDNIGHT AS A WEAKENING FRONTAL
BOUNDARY APPROACHED OUR COAST. THE FRONT WAS STRONG ENOUGH TO
GENERATE HEAVY RAIN JUST TO THE NORTH OF SONOMA COUNTY AT UKIAH.
BUT SATELLITE AND RADAR CURRENTLY INDICATE THE FRONT SOUTH OF
MENDOCINO COUNTY IS WEAK AND DISORGANIZED. AND...MODELS FORECAST
THE FRONT TO WEAKEN FURTHER AND DISSIPATE TODAY AS IT PRESSES
INLAND AND ENCOUNTERS THE UPPER RIDGE OVER THE WESTERN UNITED
STATES. THE NAM HAS FINALLY ADJUSTED ITS NORTH BAY QPF DOWNWARD
AND IS NOW IN LINE WITH OTHER MODELS IN FORECASTING MAX RAIN
TOTALS OF SLIGHTLY MORE THAN A HALF INCH IN NORTHERN SONOMA
COUNTY. RAIN AMOUNTS ARE EXPECTED TO TAPER OFF SIGNIFICANTLY
FURTHER SOUTH...TO LESS THAN A QUARTER OF AN INCH IN SOUTHERN NAPA
COUNTY AND SOUTHERN MARIN COUNTY...AND TO LESS THAN A TENTH OF AN
INCH SOUTH OF THE GOLDEN GATE. LATEST HRRR MODEL SHOWS
PRECIPITATION PEAKING IN THE NORTH BAY FOR A FEW HOURS PRIOR TO
SUNRISE...AND REACHING SAN FRANCISCO RIGHT AROUND SUNRISE. THE
HRRR ALSO INDICATES LITTLE OR NO RAIN REACHING SOUTH OF SAN MATEO
AND ALAMEDA COUNTIES TODAY. ALL MODELS AGREE THAT THE FRONT WILL
DISSIPATE BY MID AFTERNOON AND THAT MOST RAIN WILL END BY THEN.
DRY WEATHER IS EXPECTED TO RETURN TO ALL AREAS BY THIS EVENING.
A BROAD UPPER RIDGE OVER THE EASTERN PACIFIC ALONG 20N IS FORECAST
TO BUILD NORTH AND EAST ACROSS CENTRAL AND SOUTHERN CALIFORNIA ON
MONDAY AND TUESDAY...WITH H5 HEIGHTS FORECAST TO CLIMB PAST 586 DM
ACROSS THE SOUTHERN PORTION OF OUR CWA BY LATE TUESDAY. THIS
RIDGING WILL RESULT IN A COUPLE DAYS OF DRY AND MILD WEATHER.
HIGH TEMPS WILL BE IN THE 60S IN MOST AREAS...WITH LOWER 70S
LIKELY ACROSS PORTIONS OF MONTEREY AND SAN BENITO COUNTIES. THE
MODELS INDICATE THAT CONSIDERABLE HIGH LEVEL MOISTURE WILL MAKE
ITS WAY THROUGH THE RIDGE WHICH WILL RESULT IN PERIODS OF HIGH
CLOUDS ON MONDAY AND TUESDAY.
A MOIST WSWLY FLOW WILL DEVELOP ON THE NORTH SIDE OF THE RIDGE
EARLY IN THE WEEK AND BRING SIGNIFICANT RAIN INTO THE PACIFIC
NORTHWEST BY TUESDAY. THAT MOIST FLOW IS THEN FORECAST TO SAG AS
FAR SOUTH AS OUR NORTH BAY COUNTIES BY LATE TUESDAY NIGHT AND
WEDNESDAY. THE INITIAL WARM ADVECTION PRECIPITATION THAT DEVELOPS
IN OUR AREA IS EXPECTED TO REMAIN CONFINED TO THE NORTH BAY
THROUGH WEDNESDAY EVENING. AN UPPER TROUGH WILL THEN APPROACH THE
COAST AND DRIVE THE FRONTAL BOUNDARY AND ASSOCIATED RAINFALL
SOUTH THROUGH OUR ENTIRE FORECAST AREA LATE WEDNESDAY NIGHT AND
THURSDAY. THE TROUGH WILL DIG SOUTH AS IT MOVES INLAND...DRAWING A
COOL AND UNSTABLE AIRMASS SOUTH ACROSS CALIFORNIA...AND RESULTING
IN SCATTERED SHOWERS FROM THURSDAY NIGHT INTO FRIDAY MORNING. THIS
WEDNESDAY/THURSDAY SYSTEM IS CURRENTLY PROJECTED TO PRODUCE
RAINFALL TOTALS FROM A HALF INCH TO AN INCH AND A HALF OVER MUCH
OF OUR AREA. THIS SYSTEM COULD ALSO PRODUCE LOCALLY STRONG AND
GUSTY WINDS FROM WEDNESDAY EVENING THROUGH THURSDAY EVENING.
BOTH THE GFS AND ECMWF FORECAST A COLD SYSTEM TO SWEEP IN FROM THE
NORTHWEST NEXT WEEKEND...BRINGING ANOTHER ROUND OF WIDESPREAD
RAIN.
&&
.AVIATION...AS OF 4:10 AM PST SUNDAY...THE CURRENT IR SATELLITE
IMAGE IS SHOWING A COLD FRONT PUSHING TOWARDS THE TERMINALS THIS
MORNING. KMUX DOPPLER RADAR IS INDICATING RAIN SLIDING ACROSS
SONOMA AND NAPA COUNTY`S...THIS RAIN IS EXPECTED TO SPREAD SLOWLY
SOUTH INTO THE SAN FRANCISCO BAY AREA LATER THIS MORNING. HOWEVER
THE RAIN IS NOT EXPECTED TO PUSH FARTHER SOUTH THAN SANTA CRUZ.
SURFACE WINDS WILL BE PRIMARILY OUT OF THE SOUTH SOUTHEAST TODAY
AND WILL BE GUSTY THIS MORNING AS THE FRONT PASSES BY.
VICINITY OF KSFO...VFR CONDITIONS ARE EXPECTED TO PREVAIL TODAY
WITH LIGHT RAIN BEGINNING AROUND 1400Z. MODEL GUIDANCE HASN`T
BEEN THE GREATEST WITH TODAY`S SYSTEM SO BEST GUESS AT RAIN ENDING
SHOWERS BEGINNING WILL BE AROUND 1900Z WITH SHOWERS ENDING BY
2300Z. SO FAR WINDS HAVEN`T BEEN TO IMPRESSIVE AND GUIDANCE ISN`T
GREAT TODAY SO ANTICIPATING RELATIVELY LIGHT SOUTHERLY WINDS
REACHING 8 TO 12 KT THIS MORNING WITH OCCASIONAL GUSTS TO 18 KT
THROUGH ROUGHLY 1900Z.
CONFIDENCE LOW.
SFO BRIDGE APPROACH...SIMILAR TO KSFO.
MONTEREY BAY AREA TERMINALS...VFR CONDITIONS ARE EXPECTED TO
PREVAIL TODAY WITH A FEW SHOWERS IN THE VICINITY...BEST CHANCE
NORTH OF THE TERMINALS. RELATIVELY LIGHT OFFSHORE WINDS ARE
ANTICIPATED THIS MORNING WITH THE STRONGEST REACHING 8 TO 12 KT IN
THE SALINAS VALLEY.
CONFIDENCE IS MODERATE.
&&
.MARINE...AS OF 2:50 AM PST SUNDAY...SOUTHERLY WINDS ARE EXPECTED
TO PREVAIL TODAY AS A STORM SYSTEM SLIDES THROUGH THE AREA. A
LARGE LONG PERIOD WESTERLY SWELL REMAINS ON TRACK TO MOVE THROUGH
THE WATERS TONIGHT...PERSISTING INTO MONDAY. THIS SWELL WILL
RESULT IN EXCESSIVELY LARGE BREAKING WAVES ALONG COASTAL REEFS AND
SAND BARS AS WELL AS ACROSS THE SAN FRANCISCO BAR.
&&
.BEACHES...AS OF 4:18 AM PST SUNDAY...A STORM SYSTEM NOW PUSHING
INTO COASTAL BRITISH COLUMBIA HAS GENERATED A LARGE LONG PERIOD
WESTERLY SWELL WHICH IS EXPECTED TO REACH THE COAST LATE TONIGHT
STICKING AROUND THROUGH AT LEAST MONDAY EVENING. WAVES ASSOCIATED
WITH SYSTEM ARE EXPECTED TO REACH 17 TO 18 FEET WITH A PERIOD OF
17 TO 19 SECONDS...WITH OCCASIONAL SETS UP TO 20 FEET. THESE
HIGHLY ENERGETIC LONG PERIOD WAVES WILL PRODUCE EXCEPTIONALLY
LARGE SURF ALONG THE COAST ESPECIALLY NEAR DEEP WATER BREAKS SUCH
AS GHOST TREE...MARINA BEACH...MAVERICKS AND ALSO ALONG OCEAN
BEACH.
THESE LARGE BREAKING WAVES WILL PUSH WATER WELL UP ONTO THE BEACH
POSSIBLY WASHING PEOPLE FROM THE BEACH INTO THE SEA. LARGE SNEAKER
WAVES WILL ALSO BE POSSIBLE ON STEEP BEACHES SUCH AS CARMEL RIVER
BEACH AND MONTARA BEACH. PLEASE DO NOT CLIMB ON ROCKS OR JETTIES
ALONG THE COAST SINCE THESE AREAS WILL ALSO BE PRONE TO SNEAKER
WAVES. THESE WAVES WILL ARRIVE IN SETS WITH LONG LULLS BETWEEN
WAVE ACTIVITY WHICH COULD GIVE BEACH VISITORS A FALSE SENSE OF
SECURITY...DRAWING THEM CLOSER TO THE WATERS EDGE. REMEMBER TO
NEVER TURN YOUR BACK TO THE WATER AND ALWAYS KEEP AN EYE OUT FOR
RAPIDLY APPROACHING WAVES.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.TDAY...SCA...PT ARENA TO PIGEON PT 10-60 NM UNTIL 7 AM
SCA...PT ARENA TO PIGEON PT 10-60 NM FROM 7 AM
SCA...PT ARENA TO PT REYES 0-10 NM UNTIL 4 AM
SCA...PT REYES TO PIGEON PT 0-10 NM UNTIL 4 AM
SCA...ROUGH BAR ADVISORY FOR SF BAR
&&
$$
PUBLIC FORECAST: DYKEMA
AVIATION: LARRY
MARINE: LARRY
VISIT US AT WWW.WEATHER.GOV/SANFRANCISCO
FOLLOW US ON FACEBOOK AND TWITTER AT:
WWW.FACEBOOK.COM/NWSBAYAREA
WWW.TWITTER.COM/NWSBAYAREA
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
326 AM PST SUN DEC 6 2015
.SYNOPSIS...RAIN WILL SPREAD ACROSS MUCH OF THE SAN FRANCISCO BAY
AREA THIS MORNING. RAINFALL AMOUNTS WILL MOSTLY BE LIGHT. DRY AND
MILD WEATHER IS FORECAST FROM LATE TODAY THROUGH TUESDAY NIGHT.
THE NEXT PACIFIC WEATHER SYSTEM WILL WILL LIKELY BRING HEAVIER AND
MORE WIDESPREAD RAIN TO THE REGION FROM WEDNESDAY THROUGH THURSDAY
NIGHT. SHOWERS MAY LINGER INTO FRIDAY. ANOTHER SYSTEM MAY IMPACT
THE REGION NEXT WEEKEND.
&&
.DISCUSSION...AS OF 3:25 AM PST SUNDAY...RAIN BEGAN TO SPREAD
INTO THE NORTH BAY SHORTLY AFTER MIDNIGHT AS A WEAKENING FRONTAL
BOUNDARY APPROACHED OUR COAST. THE FRONT WAS STRONG ENOUGH TO
GENERATE HEAVY RAIN JUST TO THE NORTH OF SONOMA COUNTY AT UKIAH.
BUT SATELLITE AND RADAR CURRENTLY INDICATE THE FRONT SOUTH OF
MENDOCINO COUNTY IS WEAK AND DISORGANIZED. AND...MODELS FORECAST
THE FRONT TO WEAKEN FURTHER AND DISSIPATE TODAY AS IT PRESSES
INLAND AND ENCOUNTERS THE UPPER RIDGE OVER THE WESTERN UNITED
STATES. THE NAM HAS FINALLY ADJUSTED ITS NORTH BAY QPF DOWNWARD
AND IS NOW IN LINE WITH OTHER MODELS IN FORECASTING MAX RAIN
TOTALS OF SLIGHTLY MORE THAN A HALF INCH IN NORTHERN SONOMA
COUNTY. RAIN AMOUNTS ARE EXPECTED TO TAPER OFF SIGNIFICANTLY
FURTHER SOUTH...TO LESS THAN A QUARTER OF AN INCH IN SOUTHERN NAPA
COUNTY AND SOUTHERN MARIN COUNTY...AND TO LESS THAN A TENTH OF AN
INCH SOUTH OF THE GOLDEN GATE. LATEST HRRR MODEL SHOWS
PRECIPITATION PEAKING IN THE NORTH BAY FOR A FEW HOURS PRIOR TO
SUNRISE...AND REACHING SAN FRANCISCO RIGHT AROUND SUNRISE. THE
HRRR ALSO INDICATES LITTLE OR NO RAIN REACHING SOUTH OF SAN MATEO
AND ALAMEDA COUNTIES TODAY. ALL MODELS AGREE THAT THE FRONT WILL
DISSIPATE BY MID AFTERNOON AND THAT MOST RAIN WILL END BY THEN.
DRY WEATHER IS EXPECTED TO RETURN TO ALL AREAS BY THIS EVENING.
A BROAD UPPER RIDGE OVER THE EASTERN PACIFIC ALONG 20N IS FORECAST
TO BUILD NORTH AND EAST ACROSS CENTRAL AND SOUTHERN CALIFORNIA ON
MONDAY AND TUESDAY...WITH H5 HEIGHTS FORECAST TO CLIMB PAST 586 DM
ACROSS THE SOUTHERN PORTION OF OUR CWA BY LATE TUESDAY. THIS
RIDGING WILL RESULT IN A COUPLE DAYS OF DRY AND MILD WEATHER.
HIGH TEMPS WILL BE IN THE 60S IN MOST AREAS...WITH LOWER 70S
LIKELY ACROSS PORTIONS OF MONTEREY AND SAN BENITO COUNTIES. THE
MODELS INDICATE THAT CONSIDERABLE HIGH LEVEL MOISTURE WILL MAKE
ITS WAY THROUGH THE RIDGE WHICH WILL RESULT IN PERIODS OF HIGH
CLOUDS ON MONDAY AND TUESDAY.
A MOIST WSWLY FLOW WILL DEVELOP ON THE NORTH SIDE OF THE RIDGE
EARLY IN THE WEEK AND BRING SIGNIFICANT RAIN INTO THE PACIFIC
NORTHWEST BY TUESDAY. THAT MOIST FLOW IS THEN FORECAST TO SAG AS
FAR SOUTH AS OUR NORTH BAY COUNTIES BY LATE TUESDAY NIGHT AND
WEDNESDAY. THE INITIAL WARM ADVECTION PRECIPITATION THAT DEVELOPS
IN OUR AREA IS EXPECTED TO REMAIN CONFINED TO THE NORTH BAY
THROUGH WEDNESDAY EVENING. AN UPPER TROUGH WILL THEN APPROACH THE
COAST AND DRIVE THE FRONTAL BOUNDARY AND ASSOCIATED RAINFALL
SOUTH THROUGH OUR ENTIRE FORECAST AREA LATE WEDNESDAY NIGHT AND
THURSDAY. THE TROUGH WILL DIG SOUTH AS IT MOVES INLAND...DRAWING A
COOL AND UNSTABLE AIRMASS SOUTH ACROSS CALIFORNIA...AND RESULTING
IN SCATTERED SHOWERS FROM THURSDAY NIGHT INTO FRIDAY MORNING. THIS
WEDNESDAY/THURSDAY SYSTEM IS CURRENTLY PROJECTED TO PRODUCE
RAINFALL TOTALS FROM A HALF INCH TO AN INCH AND A HALF OVER MUCH
OF OUR AREA. THIS SYSTEM COULD ALSO PRODUCE LOCALLY STRONG AND
GUSTY WINDS FROM WEDNESDAY EVENING THROUGH THURSDAY EVENING.
BOTH THE GFS AND ECMWF FORECAST A COLD SYSTEM TO SWEEP IN FROM THE
NORTHWEST NEXT WEEKEND...BRINGING ANOTHER ROUND OF WIDESPREAD
RAIN.
&&
.AVIATION...AS OF 11:12 PM PST SATURDAY...VFR. SE WINDS. UPPER
TROUGH MOVES EAST OVER NORCAL TONIGHT THEN BROAD AND STRONG (FOR
DECEMBER) UPPER LEVEL RIDGING FORECAST THROUGH EARLY NEXT WEEK.
VICINITY OF KSFO...VFR/MVFR LATE TONIGHT/SUNDAY MORNING WITH LIGHT
RAIN POSSIBLE.
SFO BRIDGE APPROACH...SIMILAR TO KSFO.
MONTEREY BAY AREA TERMINALS...VFR.
&&
.MARINE...AS OF 2:50 AM PST SUNDAY...SOUTHERLY WINDS ARE EXPECTED
TO PREVAIL TODAY AS A STORM SYSTEM SLIDES THROUGH THE AREA. A
LARGE LONG PERIOD WESTERLY SWELL REMAINS ON TRACK TO MOVE THROUGH
THE WATERS TONIGHT...PERSISTING INTO MONDAY. THIS SWELL WILL
RESULT IN EXCESSIVELY LARGE BREAKING WAVES ALONG COASTAL REEFS AND
SAND BARS AS WELL AS ACROSS THE SAN FRANCISCO BAR.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.TDAY...SCA...PT ARENA TO PIGEON PT 10-60 NM UNTIL 7 AM
SCA...PT ARENA TO PIGEON PT 10-60 NM FROM 7 AM
SCA...PT ARENA TO PT REYES 0-10 NM UNTIL 4 AM
SCA...PT REYES TO PIGEON PT 0-10 NM UNTIL 4 AM
SCA...ROUGH BAR ADVISORY FOR SF BAR
&&
$$
PUBLIC FORECAST: DYKEMA
AVIATION: CANEPA
MARINE: LARRY
VISIT US AT WWW.WEATHER.GOV/SANFRANCISCO
FOLLOW US ON FACEBOOK AND TWITTER AT:
WWW.FACEBOOK.COM/NWSBAYAREA
WWW.TWITTER.COM/NWSBAYAREA
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
330 AM MST SUN DEC 6 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 324 AM MST SUN DEC 6 2015
ZONAL FLOW ALOFT WILL BE OVER NRN CO TODAY AND THEN BECOME MORE WNW
TONIGHT AS A WK DISTURBANCE MOVES ACROSS WYOMING. THERE WILL BE
SOME MID AND HIGH LVL CLOUD COVER LATER THIS MORNING THRU TONIGHT
BUT NO PCPN WILL OCCUR. HIGHS THIS AFTN OVER NERN CO WILL BE WARMER
WITH READINGS IN THE UPPER 40S TO MID 50S.
FOR TONIGHT AS THE DISTURBANCE EXITS WYOMING SUBSIDENCE WILL DVLP
OVER NRN CO BY MIDNIGHT AS A MTN WAVE FORMS. COMPONENT ALONG WINDS
INCREASE TO 40-45 KTS SO EXPECT GUSTY WINDS THRU MON MORNING IN AND
NR THE FOOTHILLS. AT THIS TIME SPEEDS SHOULD STAY JUST BLO HIGH
WIND THRESHOLD HOWEVER WILL SEE SOME GUSTS IN THE 60-70 MPH RANGE IN
THE NORMAL WINDY AREAS.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 324 AM MST SUN DEC 6 2015
MODELS HAVE MAINLY NORTHWESTERLY FLOW ALOFT FOR THE CWA MONDAY
THROUGH TUESDAY NIGHT. A JET MAXIMUM MOVES ACROSS THE CWA ON
TUESDAY. THE QG VERTICAL VELOCITY FIELDS SHOW WEAK DOWNWARD
SYNOPTIC SCALE ENERGY FOR THE CWA ALL FOUR PERIODS. THE BOUNDARY
LAYER FLOW IS DOMINATED BY DOWNSLOPING ALL FOUR PERIODS OVER MUCH
OF THE CWA. FOR MOISTURE...MONDAY AND MONDAY EVENING ARE DRY...
THEN MOISTURE INCREASES SOMEWHAT MAINLY FOR THE MOUNTAINS IN THE
NORTHWESTERLY FLOW ALOFT. IT IS FAIRLY SHALLOW AND LASTS THROUGH
TUESDAY EVENING. THINGS DRY OUT THEN. THE QPF FIELDS SHOW A TAD
OF MEASURABLE PRECIPITATION FOR THE WESTERN CWA LATER MONDAY
NIGHT INTO TUESDAY EVENING. FOR POPS...THERE IS SOME MOISTURE
...AND SOME ENHANCEMENT DUE TO OROGRAPHICS IN THE HIGH MOUNTAINS.
WILL GO WITH MINOR POPS THERE FROM TUESDAY 06Z THROUGH WEDNESDAY
06Z. CONCERNING WINDS...THERE IS A BIT OF MOUNTAINS WAVE SET MUCH
OF THE TIME. THE WINDS WILL BE FAIRLY STRONG OVER THE MOUNTAINS
AND FOOTHILLS BUT NOT UP TO HIGHLIGHT CRITERIA. FOR TEMPERATURES
...MONDAY`S HIGHS ARE 1-3 C WARMER THAN TODAY`S. TUESDAY`S HIGHS
ARE 0-2 C COOLER THAN MONDAY`S. FOR THE LATER DAYS...WEDNESDAY
THROUGH SATURDAY...MODELS HAVE STRONG NORTHWESTERLY FLOW ALOFT ON
WEDNESDAY. BY THURSDAY THE FLOW IS WESTERLY WITH 100 PLUS KNOTS
OF JET LEVEL WIND SPEEDS OVER THE CWA. BY FRIDAY...THE STRONG FLOW
ALOFT IS STILL OVER THE CWA...BUT IT IS SOUTHWESTERLY IN DIRECTION
AHEAD OF AN APPROACHING UPPER TROUGH. THE UPPER TROUGH AXIS IS
OVER THE WESTERN COLORADO BORDER AT 00Z FRIDAY LATE DAY. THE
TROUGH AXIS IS PROGGED TO MOVE EASTWARD ACROSS COLORADO THROUGH
18Z MID DAY SATURDAY. THE COLD FRONT ASSOCIATED WITH THIS SYSTEM
MOVES IN FRIDAY MORNING. RIGHT NOW IT LOOKS LIKE A SNOWFALL WILL
GET MUCH OF THE CWA...BUT IT IS MANY DAYS AWAY. THE GFS AND ECMWF
ARE IN PRETTY DECENT AGREEMENT THIS FAR OUT.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 324 AM MST SUN DEC 6 2015
WINDS WERE DRAINAGE EARLY THIS MORNING AND SHOULD REMAIN SLY THRU
18Z. FOR THIS AFTN A WK DENVER CYCLONE IS FCST TO DVLP WITH A WK
CONVERGENCE ZN NR THE AIRPORT. THUS COULD SEE VARIABLE WIND
DIRECTIONS DVLP BY 21Z. THE HRRR HAS THE WINDS BECOMING LIGHT NNW
BY 21Z THRU 00Z WHILE THE RAP KEEPS THEM SLY THRU THE AFTN. NOT SURE
WHICH WAY TO GO BUT WILL KEEP THEM SLY FOR NOW. FOR TONIGHT WINDS
WILL BE DRAINAGE.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...RPK
LONG TERM...RJK
AVIATION...RPK
AREA FORECAST DISCUSSION
NWS CARIBOU ME
912 AM EST SUN DEC 6 2015
.SYNOPSIS...
HIGH PRESSURE WILL MOVE OFFSHORE TODAY. A WEAK COLD FRONT WILL
CROSS THE REGION MONDAY. HIGH PRESSURE BUILDS OVER THE AREA MONDAY
NIGHT INTO WEDNESDAY AND MOVES EAST THURSDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATED 9:10 AM: HAVE ADJUSTED TEMPERATURE AND DEW POINT BASED ON
OBSERVATIONS. ALSO ADJUSTED SKY COVER BASED ON LATEST VISIBLE
SATELLITE.
PREVIOUS DISCUSSION...
ALL FORECASTING CHALLENGES REMAIN UNDER THE SUBSIDENCE INVERSION
AND THE H925 LAYER. WILL CONTINUE TO FAVOR THE NAM12 IN NORTHERN
ZONES WITH STRATUS AND LOW STRATOCU REFORMING OR THICKENING WITH
SUNRISE AND CONTINUING THROUGH THE DAY AND INTO THE EVENING. THE
SUBSIDENCE INVERSION WILL ERODE STEADILY AS THE UPPER RIDGE MOVES
EAST TODAY AND TONIGHT...BUT WILL REMAIN IN PLACE. WEAK
DOWNSLOPING WILL GENERATE SOME HOLES IN THE STRATOCU TONIGHT...BUT
WILL LEAN TOWARDS CLOUDY SKIES FOR THESE NORTHERN ZONES.
FOR BANGOR AND DOWN EAST...THE LOW STRATOCU IS NOT EXPECTED TO BE
A FACTOR. IN ITS PLACE...FOG AND FREEZING FOG WILL BE THE ISSUES
THIS MORNING. FOLLOWING THE RAP AND HRRR GUIDANCE...FREEZING FOG
WILL BOTH FORM AND ADVECT EASTWARD FROM ITS CURRENT POSITION IN
THE MIDCOAST. THIS FOG IS ANTICIPATED TO AFFECT BANGOR AND DOWN
EAST THROUGH THE MORNING AND POTENTIALLY INTO THE EARLY AFTERNOON.
FOG THIS MORNING WILL ALSO EXTEND UP THE PENOBSCOT RIVER VALLEY
TOWARDS HOULTON. THE FREEZING FOG WILL GENERATE SOME VERY SLICK
ROADS. WILL MAINTAIN THE SPECIAL WEATHER STATEMENT HIGHLIGHTING
THIS RISK THROUGH 8AM AND MAY EXTEND IT. THE SPECIAL WEATHER
STATEMENT IS IN EFFECT FOR THE ENTIRE FORECAST AREA AS MOISTURE
THAT HAS REFROZEN AFTER YESTERDAY`S SNOWMELT IS ALSO CAUSING
HAZARDOUS DRIVING CONDITIONS.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
SFC BNDRY WL BE LOCATED ALONG THE COAST BY THE START OF THE SHORT
TERM. WL TAKE AWHILE FOR SUBSIDENCE INVERSION TO MIX OUT WITH CLDY
CONDS EXPECTED MON MRNG OVR FAR NRN ZONES. FURTHER TO THE SOUTH
EXPECT ANOTHER MOSUNNY DAY WITH TEMPS ABV NORMAL ONCE AGAIN. MAXES
WL BE A FEW DEGREES COOLER THAN SUNDAY`S HIGHS AS H9 CLD ADVECTION
KICKS IN FOLLOWING FROPA. STILL CANNOT RULE OUT A FLURRY BEING WRUNG
OUT IN NW FLOW AS VORT MAX SCOOTS ACRS WITH UPR TROF DRG THE AFTN.
NW FLOW CONTINUES DRG THE OVRNGT HRS WITH PCLDY SKIES EXPECTED ALL
NIGHT ACRS THE NORTH WITH SOME CLRNG ACRS SRN ZONES. WINDS WL BEGIN
TO DROP OFF IN THE NORTH WOODS LATE AS HIPRES BUILDS IN FM THE WEST.
SFC RIDGE AXIS WL BE ACRS CWA DRG THE DAY TUESDAY. H5 TROF CURRENTLY
OVR THE CENTER OF THE NATION WL SWING EAST AND OFF THE MID-ATLANTIC
COAST MON NGT, WITH SFC LOW DVLPNG OFF THE CAROLINA COAST. MODELS
HV TRENDED FURTHER SOUTH AND EAST WITH THIS LOW THUS NOT EXPECTING
ANY IMPACT ON CWA BY TUESDAY OTHER THAN HIGH CLDS AND INCREASE IN
WV HEIGHTS FOR MARINE ZONES.
HIPRES WL SHIFT EAST TUE NIGHT WITH RETURN FLOW BRINGING CLDS BACK
TO THE AREA. MIN TEMPS WL BE SIMILAR TO MON NGT TEMPS WITH CLDY
SKIES AND MINIMAL WARM ADVECTION.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
TEMPS WL MODERATE THROUGHOUT THE LONG TERM AS SRLY FLOW WL
PREDOMINATE THRU THURSDAY. 00Z GFS AND EC HV ANOTHER TROF EXITING
THE MID-ATLANTIC COAST THUR MRNG WITH SFC LOW EJECTING NR THE
VIRGINIA CAPES AT THIS TIME. GFS IS FURTHER NORTH WITH TRACK OF
LOW THAN EC IS WHILE GEM DOES NOT HV ANY INDICATION OF FEATURE
EITHER AT SFC OR ALOFT. THIS LOOKS TO BE THE NEXT POTENTIAL WX-
MAKER TO WATCH THRU THE PD AS RMNDR OF EXTNDD LOOKS QUIET AND
WARM, RELATIVELY SPEAKING.
&&
.AVIATION /14Z SUNDAY THROUGH THURSDAY/...
NEAR TERM: FOG IS EXPECTED TO MOVE ACROSS THE DOWN EAST REGION
THIS MORNING...BRUSHING BGR AND LINGERING IN BHB THROUGH THE
MORNING AND POSSIBLY LONGER. FREEZING FOG IS ALSO AN ISSUE THIS
MORNING AT HUL AND FVE. THE FOG WILL LIFT TO MVFR CIGS THIS
MORNING. ALL SITES NORTH OF HUL WILL HAVE MVFR CIGS MUCH OF SUNDAY
AND INTO THE EVENING.
SHORT TERM: MVFR CIGS EXPECTED OVER NORTHERN TERMINALS ON MONDAY
THEN BECOMING VFR. ANOTHER CHC FOR MVFR RESTRICTIONS ON WED NGT
AND THU.
&&
.MARINE...
NEAR TERM: A FEW GUSTS MAY REACH NEAR 25 KTS TODAY AND THIS
EVENING...BUT DO NOT BELIEVE THE PROBABILITY AND FREQUENCY OF
THESE GUSTS WARRANTS A SMALL CRAFT ADVISORY.
SHORT TERM: SEAS AND WINDS SHOULD REMAIN UNDER SCA LEVELS THROUGH
THE PERIOD.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...MIGNONE
AREA FORECAST DISCUSSION
NWS CARIBOU ME
648 AM EST SUN DEC 6 2015
.SYNOPSIS...
HIGH PRESSURE WILL MOVE OFFSHORE TODAY. A WEAK COLD FRONT WILL
CROSS THE REGION MONDAY. HIGH PRESSURE BUILDS OVER THE AREA MONDAY
NIGHT INTO WEDNESDAY AND MOVES EAST THURSDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
7AM UPDATE...BLACK ICE CONTINUES TO BE THE BIG ISSUE THIS MORNING
AS ACCIDENTS HAVE BEEN REPORTED IN AROOSTOOK COUNTY AND THE RISK
EXISTS THROUGHOUT MOST OF THE AREA THIS MORNING. OTHERWISE...HAVE
REFINED THE FORECAST IN TERMS OF THIS MORNING`S PATCHY FREEZING
FOG AND THE CLOUD COVER. GUIDANCE IS NOW SHOWING COASTAL AREAS MAY
STAY IN THE FOG ALL DAY...WHILE BANGOR REMAINS SUNNY. FURTHER
NORTH...AM CONTINUING TO LEAN TOWARDS STRATUS FORMING WITH DAYTIME
HEATING...BUT IF THE AIR UNDER H925 IS JUST A BIT DRIER THAN
FORECAST...IT WILL BE A SUNNY DAY.
PREVIOUS DISCUSSION...
ALL FORECASTING CHALLENGES REMAIN UNDER THE SUBSIDENCE INVERSION
AND THE H925 LAYER. WILL CONTINUE TO FAVOR THE NAM12 IN NORTHERN
ZONES WITH STRATUS AND LOW STRATOCU REFORMING OR THICKENING WITH
SUNRISE AND CONTINUING THROUGH THE DAY AND INTO THE EVENING. THE
SUBSIDENCE INVERSION WILL ERODE STEADILY AS THE UPPER RIDGE MOVES
EAST TODAY AND TONIGHT...BUT WILL REMAIN IN PLACE. WEAK
DOWNSLOPING WILL GENERATE SOME HOLES IN THE STRATOCU TONIGHT...BUT
WILL LEAN TOWARDS CLOUDY SKIES FOR THESE NORTHERN ZONES.
FOR BANGOR AND DOWN EAST...THE LOW STRATOCU IS NOT EXPECTED TO BE
A FACTOR. IN ITS PLACE...FOG AND FREEZING FOG WILL BE THE ISSUES
THIS MORNING. FOLLOWING THE RAP AND HRRR GUIDANCE...FREEZING FOG
WILL BOTH FORM AND ADVECT EASTWARD FROM ITS CURRENT POSITION IN
THE MIDCOAST. THIS FOG IS ANTICIPATED TO AFFECT BANGOR AND DOWN
EAST THROUGH THE MORNING AND POTENTIALLY INTO THE EARLY AFTERNOON.
FOG THIS MORNING WILL ALSO EXTEND UP THE PENOBSCOT RIVER VALLEY
TOWARDS HOULTON. THE FREEZING FOG WILL GENERATE SOME VERY SLICK
ROADS. WILL MAINTAIN THE SPECIAL WEATHER STATEMENT HIGHLIGHTING
THIS RISK THROUGH 8AM AND MAY EXTEND IT. THE SPECIAL WEATHER
STATEMENT IS IN EFFECT FOR THE ENTIRE FORECAST AREA AS MOISTURE
THAT HAS REFROZEN AFTER YESTERDAY`S SNOWMELT IS ALSO CAUSING
HAZARDOUS DRIVING CONDITIONS.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
SFC BNDRY WL BE LOCATED ALONG THE COAST BY THE START OF THE SHORT
TERM. WL TAKE AWHILE FOR SUBSIDENCE INVERSION TO MIX OUT WITH CLDY
CONDS EXPECTED MON MRNG OVR FAR NRN ZONES. FURTHER TO THE SOUTH
EXPECT ANOTHER MOSUNNY DAY WITH TEMPS ABV NORMAL ONCE AGAIN. MAXES
WL BE A FEW DEGREES COOLER THAN SUNDAY`S HIGHS AS H9 CLD ADVECTION
KICKS IN FOLLOWING FROPA. STILL CANNOT RULE OUT A FLURRY BEING WRUNG
OUT IN NW FLOW AS VORT MAX SCOOTS ACRS WITH UPR TROF DRG THE AFTN.
NW FLOW CONTINUES DRG THE OVRNGT HRS WITH PCLDY SKIES EXPECTED ALL
NIGHT ACRS THE NORTH WITH SOME CLRNG ACRS SRN ZONES. WINDS WL BEGIN
TO DROP OFF IN THE NORTH WOODS LATE AS HIPRES BUILDS IN FM THE WEST.
SFC RIDGE AXIS WL BE ACRS CWA DRG THE DAY TUESDAY. H5 TROF CURRENTLY
OVR THE CENTER OF THE NATION WL SWING EAST AND OFF THE MID-ATLANTIC
COAST MON NGT, WITH SFC LOW DVLPNG OFF THE CAROLINA COAST. MODELS
HV TRENDED FURTHER SOUTH AND EAST WITH THIS LOW THUS NOT EXPECTING
ANY IMPACT ON CWA BY TUESDAY OTHER THAN HIGH CLDS AND INCREASE IN
WV HEIGHTS FOR MARINE ZONES.
HIPRES WL SHIFT EAST TUE NIGHT WITH RETURN FLOW BRINGING CLDS BACK
TO THE AREA. MIN TEMPS WL BE SIMILAR TO MON NGT TEMPS WITH CLDY
SKIES AND MINIMAL WARM ADVECTION.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
TEMPS WL MODERATE THROUGHOUT THE LONG TERM AS SRLY FLOW WL
PREDOMINATE THRU THURSDAY. 00Z GFS AND EC HV ANOTHER TROF EXITING
THE MID-ATLANTIC COAST THUR MRNG WITH SFC LOW EJECTING NR THE
VIRGINIA CAPES AT THIS TIME. GFS IS FURTHER NORTH WITH TRACK OF
LOW THAN EC IS WHILE GEM DOES NOT HV ANY INDICATION OF FEATURE
EITHER AT SFC OR ALOFT. THIS LOOKS TO BE THE NEXT POTENTIAL WX-
MAKER TO WATCH THRU THE PD AS RMNDR OF EXTNDD LOOKS QUIET AND
WARM, RELATIVELY SPEAKING.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
NEAR TERM: FOG IS EXPECTED TO MOVE ACROSS THE DOWN EAST REGION
THIS MORNING...BRUSHING BGR AND LINGERING IN BHB THROUGH THE
MORNING AND POSSIBLY LONGER. FREEZING FOG IS ALSO AN ISSUE THIS
MORNING AT HUL AND FVE. THE FOG WILL LIFT TO MVFR CIGS THIS
MORNING. ALL SITES NORTH OF HUL WILL HAVE MVFR CIGS MUCH OF SUNDAY
AND INTO THE EVENING.
SHORT TERM: MVFR CIGS EXPECTED OVER NORTHERN TERMINALS ON MONDAY
THEN BECOMING VFR. ANOTHER CHC FOR MVFR RESTRICTIONS ON WED NGT
AND THU.
&&
.MARINE...
NEAR TERM: A FEW GUSTS MAY REACH NEAR 25 KTS TODAY AND THIS
EVENING...BUT DO NOT BELIEVE THE PROBABILITY AND FREQUENCY OF
THESE GUSTS WARRANTS A SMALL CRAFT ADVISORY.
SHORT TERM: SEAS AND WINDS SHOULD REMAIN UNDER SCA LEVELS THROUGH
THE PERIOD.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...MCW
SHORT TERM...FARRAR
LONG TERM...FARRAR
AVIATION...MCW/FARRAR
MARINE...MCW/FARRAR
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
634 AM EST SUN DEC 6 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 436 AM EST SUN DEC 6 2015
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A SPLIT FLOW ACRS
NAMERICA DOWNWIND OF A DEEPER TROF OFF THE W COAST WITH A NEARLY
ZONAL NRN BRANCH FLOW OVER SRN CANADA AND THE SRN BRANCH FLOW IN THE
CONUS. A SHRTWV IN THE NRN BRANCH FLOW IS OVER NRN MANITOBA EARLY
THIS MRNG...WITH ASSOCIATED SFC LO NEAR THE SW EDGE OF HUDSON BAY. A
RATHER WEAK ATTENDANT SFC COLD FNT EXTENDS SWWD INTO MN. THE AIRMASS
BEHIND THE FNT IS PACIFIC IN ORIGIN...WITH 00Z H85 TEMPS NO LOWER
THAN 0-2C FM LK WINNIPEG INTO THE NRN PLAINS. THE TRAILING AIRMASS
IS QUITE DRY PER THE 00Z BISMARCK RAOB...WHERE THE PWAT WAS ONLY
0.25 INCH AT 00Z. THE PASSAGE OF STRONGER DYNAMIC FORCING IN CANADA
CLOSER TO NRN SHRTWV AND VERY DRY PREFRONTAL AIRMASS SHOWN ON THE
00Z GRB RAOB WITH DEEPER MSTR INFLOW TO THE N INTERRUPTED BY STRONG
SRN BRANCH DISTURBANCE MOVING INTO THE MID MS RIVER VALLEY IS
PREVENTING MUCH IF ANY PCPN AHEAD OF THIS APRCHG COLD FNT.
HOWEVER...THERE IS A GOOD OF LO CLD AHEAD OF THE FNT...AND THIS LO
CLD IS MOVING INTO THE WRN CWA. COMBINATION OF STEADY SW WINDS UNDER
SHARPER PRES GRADIENT BTWN THE APRCHG FNT AND HI PRES IN THE MID
ATLANTIC AND A GOOD DEAL OF HI CLDS OVER THE ENTIRE CWA/LO CLDS
MOVING INTO THE W IS LEADING TO WELL ABOVE NORMAL TEMPS OVER UPR
MI...WITH EARLY MRNG TEMPS GENERALLY 35 TO 40.
MAIN FCST CONCERNS IN THE SHORT TERM FOCUS ON SLIM PCPN CHCS/CLD
TRENDS ASSOCIATED WITH APRCHG COLD FNT. FOCUS FOR TNGT WL SHIFT TO
TEMPS AS DRIER AIRMASS BEHIND THE FNT PUSHES INTO THE UPR LKS.
TODAY...NRN BRANCH SHRTWV/SFC LO PRES ARE PROGGED TO CONTINUE TO THE
E...WITH ATTENDANT COLD FNT CROSSING UPR MI AND REACHING NEWBERRY
LATE IN THE AFTN. SINCE THE SHARPER UPR FORCING WL REMAIN TO THE N
AND S OF UPR MI...FCST SDNGS SHOW GENERALLY DRY MID LVLS BTWN HI
CLDS AND SHALLOW HIER RH ASSOCIATED WITH THE MORE ABUNDANT LO
CLDS...THERE HAVE NO PCPN REPORTS UPSTREAM...AND JUST A FEW OF EVEN
THE HIER RES MODELS GENERATE ANY PCPN OVER THE CWA...OPTED TO REMOVE
POPS EXCEPT FOR SOME SCHC POPS OVER LK SUP. DRIER MID LVL AIR IS
FCST TO FOLLOW DURING THE AFTN...BUT LO CLDS ARE LIKELY TO LINGER A
BIT LONGER WITH LO SUN ANGLE/LINGERING LLVL MSTR. SINCE HIER RES
MODEL FCST H95-9 RH HAS A PRETTY GOOD HANDLE ON THE LO CLD COVERAGE
EARLY THIS MRNG... UTILIZED THIS FCST FIELD TO HANDLE CLD TRENDS IN
THE GRIDS. THESE MODELS SHOW LO CLDS CLRG THE NW HALF OF THE CWA BY
00Z MON WITH ARRIVAL OF DRIER AIRMASS IN THE NRN PLAINS. AFTER THESE
LO CLDS ARRIVE BY 15Z OVER THE SE CWA...WL RETAIN THAT SKY COVER
OVER THE SE HALF THRU 00Z.
TNGT...LINGERING LO CLDS OVER THE SE CWA WL CLR THIS EVNG WITH
ARRIVAL OF THE DRIER AIR/PWAT AOB 0.25 INCH/SFC HI PRES RDG. WITH
LGT WINDS/MOCLR SKIES...TENDED TOWARD THE LO END OF GUIDANCE FOR MIN
TEMPS EVEN THOUGH SOME HI CLDS MAY ARRIVE LATER. RETAINED MENTION OF
SOME PATCHY GROUND FOG AS WELL WITH THE EXPECTED FVRBL RADIATIONAL
COOLING CONDITIONS.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 258 AM EST SUN DEC 6 2015
MON LOOKS TO BE THE QUIETEST DAY AS AN UPPER RIDGE PASSES OVERHEAD.
SHOULD SEE HIGHS IN THE 40S.
FORECAST FOR MON NIGHT THROUGH NEXT WEEKEND IS UNCERTAIN AS SEVERAL
SHORTWAVES MOVE THROUGH OR NEAR THE REGION...LEADING TO MAINLY LIGHT
PRECIP AT TIMES. MON NIGHT INTO TUE MORNING COULD SEE SOME VERY
MINIMAL RAIN AND POSSIBLY SOME SNOW...BUT DEFINITELY LOW CHANCES.
TUE NIGHT INTO WED MORNING COULD SEE SOME RAIN/SNOW AS A STRONGER
SHORTWAVE MOVES THROUGH THE REGION...BUT THAT WILL DEPEND ON
TRACK/STRENGTH DETAILS. THE ECMWF IS MOSTLY DRY DURING THE PERIOD
(EXCEPT FOR SOME VERY LIGHT LAKE ENHANCEMENT OVER THE E)...BUT THE
GFS AND NAM SHOW SOME GREATER PRECIP AMOUNTS (BUT STILL FAIRLY
MINOR). MODELS SHOW POTENTIAL FOR A STRONGER SYSTEM POSSIBLY LATE
THIS WEEK AND MAYBE ANOTHER STRONGER SYSTEM OVER THE WEEKEND...BUT
CONFIDENCE IS QUITE LOW. MODELS HINT AT COLDER AIR MOVING IN WITH
AND BEHIND THOSE STRONGER SYSTEMS...IF THEY MATERIALIZE.
OTHERWISE...TEMPS WILL CONTINUE TO BE WELL ABOVE NORMAL.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 629 AM EST SUN DEC 6 2015
WITH A WSHFT TO THE W BEHIND DRY MRNG COLD FROPA...EXPECT MVFR CIGS
AT IWD/CMX TO DETERIORATE TO IFR WITH UPSLOPE WIND COMPONENT.
CONCERNED THERE COULD ALSO BE SOME FOG AT CMX WITH A SHARPER UPSLOPE
COMPONENT. ALTHOUGH THE WSHFT WL ADVECT THE LLVL MSTR INTO SAW AS
WELL LATER IN THE MRNG...DOWNSLOPE NATURE OF THE W WIND WL LIKELY
HOLD CIGS IN THE MVFR RANGE THERE. ARRIVAL OF HI PRES RDG/DRIER AIR
IN THE NRN PLAINS/NW MN WL CLEAR THE LO CLDS LATER TODAY. BUT MORE
FOG/SOME LO CLDS MAY REDEVELOP TNGT WITH LGT WINDS UNDER MOCLR
SKIES. THE BEST CHANCE FOR THIS FOG TO DEVELOP WL BE AT SAW...SO
FCST PREDOMINANT IFR VSBY THERE AFT 06Z. NOT OUT OF THE QUESTION FOG
COULD REDUCE VSBY AT CMX/IWD AS WELL...BUT KEPT CONDITIONS VFR FOR
NOW.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 258 AM EST SUN DEC 6 2015
EXPECT SW WINDS TO DIMINISH TODAY AS THE PRESSURE GRADIENT
WEAKENS...REMAINING LESS THAN 25 KTS THROUGH THE REST OF THE
FORECAST PERIOD.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...TITUS
AVIATION...KC
MARINE...TITUS
AREA FORECAST DISCUSSION
NWS DULUTH MN
929 AM CST SUN DEC 6 2015
.UPDATE...
ISSUED AT 924 AM CST SUN DEC 6 2015
CLOUDS REMAINED OVER MUCH OF THE NORTHLAND THIS MORNING AND WE
SLOWED THE CLEARING THIS AFTERNOON. AREAS OF FOG ALSO
CONTINUED...DENSE IN SPOTS...AND WE EXTENDED THE MENTION THROUGH
NOON.
THE 12Z KINL SOUNDING SHOWED A STRONG INVERSION WITH VERY SHALLOW
MOISTURE. THE KMPX SOUNDING HAD DEEPER MOISTURE. THE LACK OF
STRONG FLOW AND WEAK SUN WILL KEEP THE CLOUDS AND FOG AROUND
LONGER TODAY. TEMPERATURES WERE ALSO LOWERED A COUPLE DEGREES
WHERE WE EXPECT THE CLOUDS TO LAST THE LONGEST.
ADDITIONAL ADJUSTMENTS TO INCREASE CLOUDS FURTHER THIS
AFTERNOON/TONIGHT MAY BE NEEDED AND WE MAY HAVE TO ADD MORE FOG TO
THE FORECAST.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 342 AM CST SUN DEC 6 2015
CLOUDS THE MAIN CONCERN OF THE FORECAST FOR THE NEXT 24-36 HOURS.
STRATUS FORMED SATURDAY DESPITE CONCERNS THAT IT WOULD NOT...SO AM
GOING TO BE MORE PESSIMISTIC ON CLOUD COVER THAN THE GUIDANCE
CURRENTLY SHOWS. STRATUS HAS MADE VERY SLOW PROGRESS EAST IN THE
PAST SEVERAL HOURS...AND DO NOT EXPECT THIS TO INCREASE AND MAY EVEN
STALL BETWEEN NOW AND SUNRISE...ESPECIALLY WHERE FOG HAS FORMED.
THEN...WITH A STRONG LOW LEVEL INVERSION AND LIGHT WINDS EXPECT POOR
PROGRESS ON CLEARING DESPITE THE COLD FRONT FINALLY MOVING BODILY
OFF TO THE EAST TODAY. THUS...HAVE SIMILAR CLOUD CONDITIONS TO
CURRENT THROUGH MID MORNING...BEFORE ALLOWING A GRADUAL CLEARING
TREND FROM WEST TO EAST THROUGH THE AFTERNOON AND EVENING. THIS
CLOUD COVER MAKES OUR MAX TEMPERATURE FORECAST DIFFICULT AS WELL...
AS THE MODELS HAVER FASTER CLEARING...BUT HAVE OVERDONE THE SURFACE
SNOW COVER AND ARE TOO COLD AND MOIST AT THE SURFACE. HAVE GONE
WITH UPPER 30S TO LOW 40S FOR NOW...BUT AM NOT TERRIBLY CONFIDENT IN
THIS TODAY. TONIGHT A LITTLE EASIER WITH THE STRATUS CLOUDS FINALLY
CLEARED OUT AND ONLY SOME HIGHER CLOUD COMING IN FROM THE WEST. HAVE
GONE WITH DECENT RADIATIONAL COOLING AND LOW END OF GUIDANCE MIN
TEMPS. MONDAY SHOULD HAVE PLENTY OF MID AND HIGH CLOUD COVER WITH A
SHORTWAVE MOVING ACROSS MINNESOTA...BUT THE MOISTURE IS ALL MID AND
HIGH LEVEL AND DO NOT EXPECT ANYTHING MORE THAN CLOUDS. CONSENSUS
TEMPERATURES REASONABLE.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 342 AM CST SUN DEC 6 2015
A SERIES OF ABOUT THREE DISTINCT CLIPPER-LIKE DISTURBANCES IN THE
QUASI-ZONAL UPPER FLOW THROUGH MUCH OF THE WORK WEEK BEFORE A MAJOR
PATTERN CHANGE THIS WEEKEND. THE SENSIBLE WEATHER IMPACTS WILL BE
MINIMAL WITH LOW CHANCES FOR PRECIPITATION AND WELL ABOVE NORMAL
TEMPERATURES. WITH THE MILD TEMPERATURES PRECIPITATION TYPE WILL BE
A MIX OF RAIN AND SNOW THROUGH THE WEEK...WITH GENERALLY LIGHT
PRECIP AMOUNTS EXPECTED.
ON THE SYNOPTIC SCALE THE WEEK BEGINS WITH A MID-LEVEL TROUGH AXIS
ACROSS THE NORTHERN PLAINS...MOVING INTO THE UPPER MIDWEST MONDAY
NIGHT...FOLLOWED BY BRIEF RIDGING...THEN ANOTHER DEEPER MID-LEVEL
TROUGH TUESDAY NIGHT. WEDNESDAY ZONAL FLOW TAKES HOLD ACROSS THE
NORTHERN PLAINS AND UPPER MISSISSIPPI VALLEY BEFORE BECOMING
SOUTHWESTERLY THURSDAY AHEAD OF A YET DEEPER DISTURBANCE WITH AN
UPPER LOW CENTERED NEAR WINNIPEG THURSDAY MORNING. THIS UPPER LOW
MOVES EAST THROUGH THE DAY THOUGH THE EXACT TRACK IS LESS CERTAIN
THAN THE UPPER FLOW FROM THE FIRST FEW DAYS OF THE WEEK AS GUIDANCE
BEGINS TO DIVERGE...WHICH IS TO BE EXPECTED AT THIS TIME RANGE.
HOWEVER...WHILE THERE IS INCONSISTENCY WITH REGARDS TO THE WEAKER
SYSTEMS THAT MOVE ACROSS THE UPPER MIDWEST THERE IS A STRONG SIGNAL
FOR A DEEPENING LONGWAVE TROUGH OVER THE WESTERN CONUS...WITH A DEEP
TROUGH CENTERED OVER THE FOUR CORNERS REGION BY SATURDAY MORNING.
THIS WILL RESULT IN A SOUTHWESTERLY FLOW PATTERN ALOFT EMERGING BY
THE END OF THE WORK WEEK AND INTO THE WEEKEND OVER THE NORTHLAND.
WHILE BEYOND THE CURRENT FORECAST PERIOD...THIS DEEP LONGWAVE TROUGH
WILL EVENTUALLY EJECT INTO THE GREAT PLAINS AND AN ASSOCIATED SFC
LOW MOVING ACROSS THE MISSISSIPPI VALLEY...WHICH COULD RESULT IN A
MORE SUBSTANTIAL CHANCE OF PRECIPITATION LATER IN THE WEEKEND.
PRECIPITATION CHANCES FROM THE PARADE OF DISTURBANCES IS FAIRLY LOW
DUE TO A COMBINATION OF LACK OF DEEP MOISTURE AND LESS-THAN-IDEAL
LARGE-SCALE LIFT. THE USUAL MODEL DIFFERENCES RESULTS IN LOW PRECIP
CHANCES THROUGH MUCH OF THE WEEK...BUT IT SHOULD BE NOTED THAT IT IS
NOT EXPECT TO RAIN/SNOW ALL WEEK LONG...AND THAT THESE CHANCES WILL
BE REFINED. IN TERMS OF ANYTHING MORE THAN A TENTH OF AN INCH OF
LIQUID-EQUIVALENT THE BEST CHANCE WILL BE WED NIGHT INTO THURSDAY
WHEN THE BEST DEEP-LAYER MOISTURE IS PRESENT AHEAD OF THE SFC LOW.
PRECIPITABLE WATER VALUES WILL BE OVER A HALF INCH WITH SOME
GUIDANCE /GFS/ DEPICTING OVER THREE-QUARTERS OF AN INCH IN SOME
LOCATIONS. WHILE THIS MAY BE OVERDONE...IT HIGHLIGHTS THE BEST
CHANCE FOR WIDESPREAD PRECIP. IN TERMS OF PRECIPITATION TYPE...NEAR-
SURFACE TEMPS WILL BE NEAR FREEZING MUCH OF THE WEEK...BUT WITH
UNSEASONABLY WARM AIR ALOFT...850MB TEMPS RANGING FROM -3 TO +5...A
MIX OF RAIN AND SNOW IS EXPECTED. THE ONE EXCEPTION IS MON NIGHT
INTO TUESDAY MORNING WHERE THE NAM/SREF DEPICT A MUCH COLDER LAYER
OF AIR AT THE SFC WHICH COULD RESULT IN A BRIEF PERIOD FREEZING
RAIN/DRIZZLE BEFORE PRECIP CHANCES TO ALL RAIN TUESDAY AFTERNOON.
DECIDED TO STICK WITH A STRAIGHT RAIN/SNOW MIX FOR NOW SINCE THE
NAM/SREF TEND TO BE OVERDONE WITH THE LOW LEVEL MOISTURE.
HIGHS IN THE UPPER 30S TO MID 40S THROUGH THE WORK WEEK...THEN A BIT
COOLER THIS WEEKEND WITH HIGHS DOWN TO LOW 30S TO NEAR 40 ON
SATURDAY...COLDEST IN FAR NORTHERN MINNESOTA. LOWS IN THE UPPER 20S
TO LOW 30S MOST NIGHTS...WITH AGAIN THE COLDER TEMPS ARRIVING FOR
THE WEEKEND. NORMAL HIGHS RANGE FROM THE LOW TO MID 20S AND NORMAL
LOWS IN THE SINGLE DIGITS.
PUTTING THE VERY WARM TEMPERATURES INTO CONTEXT...WHILE WE WILL BE
15 TO 20 DEGREES ABOVE NORMAL MOST HIGH TEMPERATURE RECORDS WILL BE
OUT OF REACH AT DLH WITH MOST RECORD HIGHS THIS WEEK IN THE LOW/MID
50S...THE EXCEPTIONS BEING DEC 8 /45/ AND DEC 10 /46/. AT
INTERNATIONAL FALLS OUR FORECAST HIGH IS WITHIN A DEGREE OF THE
RECORD HIGH ON DEC 10 /RECORD 41...FORECAST 40/...WITH THE REST OF
THE RECORD HIGHS THROUGH THE FORECAST PERIOD LIKELY OUT OF REACH.
HOWEVER...IN TERMS OF RECORD HIGH MINIMUM TEMPS /AKA WARMEST LOW
TEMPS/ WE APPROACH RECORDS ON MULTIPLE DAYS THIS WEEK AT BOTH
SITES...SO EXPECT TO SEE RECORD REPORTS ON A FEW DAYS THIS WEEK FOR
THE UNUSUALLY WARM NIGHTS AHEAD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 545 AM CST SUN DEC 6 2015
IFR TO LIFR CONDITIONS THIS MORNING WILL LIKELY GRADUALLY IMPROVE
TO VFR THIS AFTERNOON...THOUGH THERE IS A SMALL CHANCE MVFR OR
WORSE CEILINGS/VISIBILITY CONTINUE THROUGH THE DAY AT SOME
SITES...PARTICULARLY DLH. WINDS LIGHT THROUGH THE DAY OUT OF THE
SOUTHWEST TO SOUTH AT LESS THAN 10 KTS...BECOMING NEAR CALM
TONIGHT. CEILINGS LESS THAN 1KFT ARE EXPECTED TO IMPROVE TODAY AS
CLEAR IS ALREADY MOVING ACROSS NORTH CENTRAL MINNESOTA EARLY THIS
MORNING PER SATELLITE IMAGERY AND OBSERVATIONS...THOUGH THE
PROGRESSION OF THE CLEARING IS VERY SLOW. THIS IS EXPECTED TO
PICK UP THROUGH THE MORNING WITH IMPROVEMENT TO VFR AT ALL SITES
BY THE LATE MORNING/EARLY AFTERNOON. ALONG THE BACK EDGE OF THE
CLEARING VISIBILITIES HAVE FALLEN DRAMATICALLY...AND A REDUCTION
TO LIFR VISIBILITY IS POSSIBLE AT BRD FOR A TIME THIS MORNING
BEFORE SKIES CLEAR OUT. THE HRRR MODEL IS AGGRESSIVE ABOUT THE
CLEARING LINE BARELY BUDGING ALL DAY...BUT GIVEN TRENDS OVERNIGHT
BELIEVE CLEARING/IMPROVEMENT TO VFR WILL OCCUR BY LATE MORNING
INTO THE EARLY AFTERNOON.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 39 25 40 29 / 0 0 0 0
INL 40 23 42 28 / 0 0 0 0
BRD 38 24 42 28 / 0 0 0 0
HYR 40 22 43 30 / 0 0 0 0
ASX 40 23 44 32 / 0 0 0 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
LS...NONE.
&&
$$
UPDATE...MELDE
SHORT TERM...LE
LONG TERM...JJM
AVIATION...JJM
AREA FORECAST DISCUSSION
NWS DULUTH MN
545 AM CST SUN DEC 6 2015
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 342 AM CST SUN DEC 6 2015
CLOUDS THE MAIN CONCERN OF THE FORECAST FOR THE NEXT 24-36 HOURS.
STRATUS FORMED SATURDAY DESPITE CONCERNS THAT IT WOULD NOT...SO AM
GOING TO BE MORE PESSIMISTIC ON CLOUD COVER THAN THE GUIDANCE
CURRENTLY SHOWS. STRATUS HAS MADE VERY SLOW PROGRESS EAST IN THE
PAST SEVERAL HOURS...AND DO NOT EXPECT THIS TO INCREASE AND MAY EVEN
STALL BETWEEN NOW AND SUNRISE...ESPECIALLY WHERE FOG HAS FORMED.
THEN...WITH A STRONG LOW LEVEL INVERSION AND LIGHT WINDS EXPECT POOR
PROGRESS ON CLEARING DESPITE THE COLD FRONT FINALLY MOVING BODILY
OFF TO THE EAST TODAY. THUS...HAVE SIMILAR CLOUD CONDITIONS TO
CURRENT THROUGH MID MORNING...BEFORE ALLOWING A GRADUAL CLEARING
TREND FROM WEST TO EAST THROUGH THE AFTERNOON AND EVENING. THIS
CLOUD COVER MAKES OUR MAX TEMPERATURE FORECAST DIFFICULT AS WELL...
AS THE MODELS HAVER FASTER CLEARING...BUT HAVE OVERDONE THE SURFACE
SNOW COVER AND ARE TOO COLD AND MOIST AT THE SURFACE. HAVE GONE
WITH UPPER 30S TO LOW 40S FOR NOW...BUT AM NOT TERRIBLY CONFIDENT IN
THIS TODAY. TONIGHT A LITTLE EASIER WITH THE STRATUS CLOUDS FINALLY
CLEARED OUT AND ONLY SOME HIGHER CLOUD COMING IN FROM THE WEST. HAVE
GONE WITH DECENT RADIATIONAL COOLING AND LOW END OF GUIDANCE MIN
TEMPS. MONDAY SHOULD HAVE PLENTY OF MID AND HIGH CLOUD COVER WITH A
SHORTWAVE MOVING ACROSS MINNESOTA...BUT THE MOISTURE IS ALL MID AND
HIGH LEVEL AND DO NOT EXPECT ANYTHING MORE THAN CLOUDS. CONSENSUS
TEMPERATURES REASONABLE.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 342 AM CST SUN DEC 6 2015
A SERIES OF ABOUT THREE DISTINCT CLIPPER-LIKE DISTURBANCES IN THE
QUASI-ZONAL UPPER FLOW THROUGH MUCH OF THE WORK WEEK BEFORE A MAJOR
PATTERN CHANGE THIS WEEKEND. THE SENSIBLE WEATHER IMPACTS WILL BE
MINIMAL WITH LOW CHANCES FOR PRECIPITATION AND WELL ABOVE NORMAL
TEMPERATURES. WITH THE MILD TEMPERATURES PRECIPITATION TYPE WILL BE
A MIX OF RAIN AND SNOW THROUGH THE WEEK...WITH GENERALLY LIGHT
PRECIP AMOUNTS EXPECTED.
ON THE SYNOPTIC SCALE THE WEEK BEGINS WITH A MID-LEVEL TROUGH AXIS
ACROSS THE NORTHERN PLAINS...MOVING INTO THE UPPER MIDWEST MONDAY
NIGHT...FOLLOWED BY BRIEF RIDGING...THEN ANOTHER DEEPER MID-LEVEL
TROUGH TUESDAY NIGHT. WEDNESDAY ZONAL FLOW TAKES HOLD ACROSS THE
NORTHERN PLAINS AND UPPER MISSISSIPPI VALLEY BEFORE BECOMING
SOUTHWESTERLY THURSDAY AHEAD OF A YET DEEPER DISTURBANCE WITH AN
UPPER LOW CENTERED NEAR WINNIPEG THURSDAY MORNING. THIS UPPER LOW
MOVES EAST THROUGH THE DAY THOUGH THE EXACT TRACK IS LESS CERTAIN
THAN THE UPPER FLOW FROM THE FIRST FEW DAYS OF THE WEEK AS GUIDANCE
BEGINS TO DIVERGE...WHICH IS TO BE EXPECTED AT THIS TIME RANGE.
HOWEVER...WHILE THERE IS INCONSISTENCY WITH REGARDS TO THE WEAKER
SYSTEMS THAT MOVE ACROSS THE UPPER MIDWEST THERE IS A STRONG SIGNAL
FOR A DEEPENING LONGWAVE TROUGH OVER THE WESTERN CONUS...WITH A DEEP
TROUGH CENTERED OVER THE FOUR CORNERS REGION BY SATURDAY MORNING.
THIS WILL RESULT IN A SOUTHWESTERLY FLOW PATTERN ALOFT EMERGING BY
THE END OF THE WORK WEEK AND INTO THE WEEKEND OVER THE NORTHLAND.
WHILE BEYOND THE CURRENT FORECAST PERIOD...THIS DEEP LONGWAVE TROUGH
WILL EVENTUALLY EJECT INTO THE GREAT PLAINS AND AN ASSOCIATED SFC
LOW MOVING ACROSS THE MISSISSIPPI VALLEY...WHICH COULD RESULT IN A
MORE SUBSTANTIAL CHANCE OF PRECIPITATION LATER IN THE WEEKEND.
PRECIPITATION CHANCES FROM THE PARADE OF DISTURBANCES IS FAIRLY LOW
DUE TO A COMBINATION OF LACK OF DEEP MOISTURE AND LESS-THAN-IDEAL
LARGE-SCALE LIFT. THE USUAL MODEL DIFFERENCES RESULTS IN LOW PRECIP
CHANCES THROUGH MUCH OF THE WEEK...BUT IT SHOULD BE NOTED THAT IT IS
NOT EXPECT TO RAIN/SNOW ALL WEEK LONG...AND THAT THESE CHANCES WILL
BE REFINED. IN TERMS OF ANYTHING MORE THAN A TENTH OF AN INCH OF
LIQUID-EQUIVALENT THE BEST CHANCE WILL BE WED NIGHT INTO THURSDAY
WHEN THE BEST DEEP-LAYER MOISTURE IS PRESENT AHEAD OF THE SFC LOW.
PRECIPITABLE WATER VALUES WILL BE OVER A HALF INCH WITH SOME
GUIDANCE /GFS/ DEPICTING OVER THREE-QUARTERS OF AN INCH IN SOME
LOCATIONS. WHILE THIS MAY BE OVERDONE...IT HIGHLIGHTS THE BEST
CHANCE FOR WIDESPREAD PRECIP. IN TERMS OF PRECIPITATION TYPE...NEAR-
SURFACE TEMPS WILL BE NEAR FREEZING MUCH OF THE WEEK...BUT WITH
UNSEASONABLY WARM AIR ALOFT...850MB TEMPS RANGING FROM -3 TO +5...A
MIX OF RAIN AND SNOW IS EXPECTED. THE ONE EXCEPTION IS MON NIGHT
INTO TUESDAY MORNING WHERE THE NAM/SREF DEPICT A MUCH COLDER LAYER
OF AIR AT THE SFC WHICH COULD RESULT IN A BRIEF PERIOD FREEZING
RAIN/DRIZZLE BEFORE PRECIP CHANCES TO ALL RAIN TUESDAY AFTERNOON.
DECIDED TO STICK WITH A STRAIGHT RAIN/SNOW MIX FOR NOW SINCE THE
NAM/SREF TEND TO BE OVERDONE WITH THE LOW LEVEL MOISTURE.
HIGHS IN THE UPPER 30S TO MID 40S THROUGH THE WORK WEEK...THEN A BIT
COOLER THIS WEEKEND WITH HIGHS DOWN TO LOW 30S TO NEAR 40 ON
SATURDAY...COLDEST IN FAR NORTHERN MINNESOTA. LOWS IN THE UPPER 20S
TO LOW 30S MOST NIGHTS...WITH AGAIN THE COLDER TEMPS ARRIVING FOR
THE WEEKEND. NORMAL HIGHS RANGE FROM THE LOW TO MID 20S AND NORMAL
LOWS IN THE SINGLE DIGITS.
PUTTING THE VERY WARM TEMPERATURES INTO CONTEXT...WHILE WE WILL BE
15 TO 20 DEGREES ABOVE NORMAL MOST HIGH TEMPERATURE RECORDS WILL BE
OUT OF REACH AT DLH WITH MOST RECORD HIGHS THIS WEEK IN THE LOW/MID
50S...THE EXCEPTIONS BEING DEC 8 /45/ AND DEC 10 /46/. AT
INTERNATIONAL FALLS OUR FORECAST HIGH IS WITHIN A DEGREE OF THE
RECORD HIGH ON DEC 10 /RECORD 41...FORECAST 40/...WITH THE REST OF
THE RECORD HIGHS THROUGH THE FORECAST PERIOD LIKELY OUT OF REACH.
HOWEVER...IN TERMS OF RECORD HIGH MINIMUM TEMPS /AKA WARMEST LOW
TEMPS/ WE APPROACH RECORDS ON MULTIPLE DAYS THIS WEEK AT BOTH
SITES...SO EXPECT TO SEE RECORD REPORTS ON A FEW DAYS THIS WEEK FOR
THE UNUSUALLY WARM NIGHTS AHEAD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 545 AM CST SUN DEC 6 2015
IFR TO LIFR CONDITIONS THIS MORNING WILL LIKELY GRADUALLY IMPROVE
TO VFR THIS AFTERNOON...THOUGH THERE IS A SMALL CHANCE MVFR OR
WORSE CEILINGS/VISIBILITY CONTINUE THROUGH THE DAY AT SOME
SITES...PARTICULARLY DLH. WINDS LIGHT THROUGH THE DAY OUT OF THE
SOUTHWEST TO SOUTH AT LESS THAN 10 KTS...BECOMING NEAR CALM
TONIGHT. CEILINGS LESS THAN 1KFT ARE EXPECTED TO IMPROVE TODAY AS
CLEAR IS ALREADY MOVING ACROSS NORTH CENTRAL MINNESOTA EARLY THIS
MORNING PER SATELLITE IMAGERY AND OBSERVATIONS...THOUGH THE
PROGRESSION OF THE CLEARING IS VERY SLOW. THIS IS EXPECTED TO
PICK UP THROUGH THE MORNING WITH IMPROVEMENT TO VFR AT ALL SITES
BY THE LATE MORNING/EARLY AFTERNOON. ALONG THE BACK EDGE OF THE
CLEARING VISIBILITIES HAVE FALLEN DRAMATICALLY...AND A REDUCTION
TO LIFR VISIBILITY IS POSSIBLE AT BRD FOR A TIME THIS MORNING
BEFORE SKIES CLEAR OUT. THE HRRR MODEL IS AGGRESSIVE ABOUT THE
CLEARING LINE BARELY BUDGING ALL DAY...BUT GIVEN TRENDS OVERNIGHT
BELIEVE CLEARING/IMPROVEMENT TO VFR WILL OCCUR BY LATE MORNING
INTO THE EARLY AFTERNOON.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 41 25 40 29 / 0 0 0 0
INL 38 23 42 28 / 0 0 0 0
BRD 40 24 42 28 / 0 0 0 0
HYR 42 22 43 30 / 0 0 0 0
ASX 42 23 44 32 / 0 0 0 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
LS...NONE.
&&
$$
SHORT TERM...LE
LONG TERM...JJM
AVIATION...JJM
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
614 AM EST SUN DEC 6 2015
.SYNOPSIS...
AN UPPER LOW AND WEAK OFFSHORE SYSTEM WILL BRING MAINLY
COASTAL RAIN LATE TONIGHT AND MONDAY. HIGH PRESSURE WILL BRING
BACK SUNSHINE AND SEASONABLE TEMPERATURES THROUGH THE MIDDLE OF
THE WEEK POSSIBLY FOLLOWED BY A WEEKEND WARMUP.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM SUNDAY...NO CHANGES TO THE FORECAST WITH THE LATEST
UPDATE. PREVIOUS DISCUSSION FOLLOWS:
COOL HIGH PRESSURE CENTERED TO THE NORTH WILL WEAKEN TODAY AND
TONIGHT AS A COASTAL TROUGH FORMS OFFSHORE. LOW LEVEL MOISTURE
ADVECTION IN COMBINATION WITH LIFT ASSOCIATED WITH THIS NASCENT
TROUGH AND A VIGOROUS APPROACHING SHORT WAVE WILL INCREASE THE
CHANCES FOR STRATIFORM RAIN OVERNIGHT...MAINLY AFTER MIDNIGHT IN
THE PRE-DAWN HOURS OF MONDAY. UNTIL THEN...THE DAY WILL START OFF
WITH AT LEAST PATCHY STRATUS ALONG THE COAST ADVECTING IN FROM THE
OCEAN AND SPREADING INLAND. MUCH OF THIS WILL LIFT AND SCATTER OUR
THIS AFTERNOON...WITH OVERCAST CONDITIONS RETURNING FOR THE
OVERNIGHT PERIOD. MILD AND SLIGHTLY ABOVE AVERAGE TEMPERATURES IN
STORE FOR TODAY...WITH MODEL CONSENSUS GIVING US HIGHS IN THE
LOWER 60S MOST PLACES...WITH LOWS IN THE MID 40S.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 3 AM SUNDAY...GUIDANCE CONTINUES TO SHOW THAT DESPITE A FAIRLY
POTENT SHORTWAVE COMING ACROSS ON MONDAY THAT THE DEEPEST MOISTURE
AND THUS BEST RAIN CHANCES WILL REMAIN QUITE CONFINED TO THE COAST.
GIVEN THAT THERE COULD BE A CONSIDERABLE WEST-TO-EAST GRADIENT IN
BOTH RAIN CHANCES AND AMOUNTS GETTING THE AMOUNTS RIGHT IS A BIT
TRICKY AS THEY WILL BE HIGHLY SUBJECT TO SMALL DEVIATIONS IN THE
PATH OF THE FLAT WAVE OFFSHORE THAT MOVES UP THE COAST. COASTAL NC
LOOKS TO NET THE MOST RAIN WITH ABOUT A THIRD OF AN INCH POSSIBLE.
LOW AMPLITUDE ALOFT TAKES OVER MONDAY NIGHT AND THUS RAPID DRYING
FOR CLEARING SKY THAT WILL PERSIST INTO TUESDAY. ANY COOL ADVECTION
ASSOC WITH THIS SYSTEM IS UNDONE ON TUESDAY SO TEMPERATURES TUESDAY
WILL BE NEAR CLIMO IN A WEAKLY WARM ADVECTING BUT ALSO SHALLOW MIXED
REGIME.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 3 AM SUNDAY...UPPER TROUGH POISED TO SWING THROUGH OUR
LONGITUDE LATE WEDNESDAY OR WEDNESDAY NIGHT. THIS FEATURE WILL BE
MOISTURE-CHALLENGED ENOUGH AND ALSO HAVE A POOR ENOUGH SURFACE
REFLECTION TO NOT BRING MEANINGFUL RAIN CHANCES. FLOW QUICKLY
FLATTENS THURSDAY FOR ANOTHER SEASONABLE AND DRY DAY. MODELS IN GOOD
AGREEMENT THAT A FAIRLY STRONG MID LEVEL RIDGE AND LOW LEVEL RETURN
FLOW THEN GET UNDERWAY BUT NOT SO MUCH IN THE TIMING. RIDGE MAY WELL
BE IN ITS FORMATIVE STAGES ON FRIDAY ACCORDING TO QUICKER PROGS
WHEREAS OTHERS WISH TO DELAY THINGS BY ABOUT A DAY. EITHER WAY NO
PRECIP CHANCES TO BE HAD. THE TROUGH OVER THE WESTERN U.S. WILL
BECOME QUITE DEEP WHICH COULD TRANSLATE TO SOME LOCAL WEATHER NOT
LONG AFTER THE LONG TERM PERIOD.
&&
.AVIATION /11Z SUNDAY THROUGH THURSDAY/...
AS OF 06Z...VFR CONDITIONS WILL CONTINUE FOR THE NEXT FEW HOURS
WITH NORTHEAST FLOW ACROSS THE TAF SITES. MODELS CONTINUE TO SHOW
LOW-LEVEL MOISTURE INCREASING OVERNIGHT AND THE 00 UTC
EXPERIMENTAL RUN OF THE HRRR IS SHOWING IF STRATUS AND FOG DEVELOPING
OVER ALL TAF SITES EXCEPT KMYR AND KCRE GENERALLY BETWEEN 9 AND 12
UTC BEFORE BREAKING UP AFTER SUNRISE.
EXTENDED AVIATION OUTLOOK...POTENTIAL FOR RESTRICTIONS TO DEVELOP
ON MONDAY WITH LOW CLOUDS AND SHOWERS. OTHERWISE EXPECT VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM SUNDAY...NO CHANGES TO THE FORECAST WITH THE LATEST
UPDATE. PREVIOUS DISCUSSION FOLLOWS:
AS OF 330 AM SUNDAY...SMALL CRAFT ADVISORY REMAINS IN EFFECT
THROUGH THE AFTERNOON HOURS AS A WEAKENING HIGH PRESSURE SYSTEM
CENTERED TO THE NORTH MAINTAINS A COOL NORTHEASTERLY FLOW THROUGH
THE PERIOD. HAVE CANCELED THE ADVISORY FOR THE OVERNIGHT PORTION
OF THE FORECAST AS SEAS WILL HAVE DROPPED BELOW CRITERIA BY THEN.
WINDS HAVE ALREADY DROPPED BELOW SMALL CRAFT ADVISORY CRITERIA.
MOST AREAS WILL EXPERIENCE NE WINDS IN THE 15 TO 20 KT RANGE
TODAY...WITH 4 TO 6 FT SEAS. EXPECT GRADUALLY IMPROVING CONDITIONS
THIS EVENING...WITH SEAS IN THE 3 TO 5 FT RANGE OVERNIGHT.
SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 3 AM SUNDAY... AN UPPER LOW WILL SWING BY JUST NORTH OF THE
AREA ON MONDAY. DESPITE THIS FEATURE HAVING SOME STRENGTH TO IT
HOWEVER THERE WILL BE LITTLE TO NO SURFACE REFLECTION. WHILE THERE
WILL BE SOME VISIBILITY-LIMITING SHOWERS AROUND WIND AND SEAS
SHOULD ACTUALLY CONTINUE THEIR GRADUAL ABATING TREND AND NO
HEADLINES ARE ANTICIPATED AT THIS TIME. MONDAY NIGHT AS THIS
SYSTEM MOVES OFFSHORE IT DOES APPEAR TO INTERACT WITH LOW LEVEL
FRONTAL BOUNDARY AND LEAD TO DEEPENING LOW PRESSURE WILL OFF
DELMARVA COAST. THIS MAY SLIGHTLY AND BRIEFLY BOLSTER LOCAL WINDS
BUT BY TUESDAY THE DIMINISHING TREND RESUMES AS HIGH PRESSURE
BUILDS WEAKLY INTO THE SOUTHEASTERN U.S.
LONG TERM /WEDNESDAY THROUGH THURSDAY/...
AS OF 3 AM SUNDAY... PRESSURE PATTERN GROWS SO WEAK ON WEDNESDAY
THAT WE ARE LIKELY LOOKING AT VERY LIGHT WINDS AND CONSIDERABLE
VARIABILITY IN WIND DIRECTION. THIS WILL GIVE SEAS A CHANCE TO
SETTLE TO NEAR MINIMAL VALUES OF 2 FT OR LESS. ANOTHER UPPER
SYSTEM MOVING RAPIDLY OFF THE VA COAST ON THURSDAY WILL BRING A
TURN TO W OR NW AND A VERY SHORT-LIVED SURGE IN WIND SPEED. THIS
SYSTEM WILL MOVE QUICKLY HOWEVER AND EXPECT THAT A GENERAL 10 KT
FORECAST WILL STILL BE THE FLAVOR OF MOST OF THE DAY AND EVENING.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS EVENING FOR AMZ250-
252-254-256.
&&
$$
SYNOPSIS...MBB
NEAR TERM...REK
SHORT TERM...MBB
LONG TERM...MBB
AVIATION...DRH
MARINE...REK/MBB
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
957 AM CST SUN DEC 6 2015
.UPDATE...
ISSUED AT 955 AM CST SUN DEC 6 2015
UPDATED TO EXTEND THE DENSE FOG ADVISORY IN NORTHWEST IOWA UNTIL
NOON. AT 9 AM...MANY SITES WERE STILL AT A QUARTER MILE OR LESS IN
VISIBILITY...AND SATELLITE IMAGERY SHOWS THE STRATUS ONLY VERY
SLOWLY ERODING. CURRENT THOUGHTS ARE THAT THE VISIBILITY WILL
IMPROVE BY MIDDAY...BUT THE STRATUS MAY BE TOUGH TO GET RID OF IN
OUR EXTREME SOUTHEAST ZONES. THEREFORE COOLER HIGHS IN THAT LOCATION
ARE STILL WARRANTED.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 346 AM CST SUN DEC 6 2015
LOW CONFIDENCE TODAY IN TERMS OF SKY COVER AND TEMPERATURES.
CURRENTLY...TROUGH MOVING THROUGH THE AREA WITH FAIRLY DENSE AND
WIDESPREAD FOG AHEAD OF THE TROUGH. BEHIND THE TROUGH...PATCHY FOG
PERSISTS AND WITH WEAK WINDS AND STOUT INVERSION REMAINING ACROSS
THE AREA...QUESTIONS REMAIN AS TO HOW QUICK THE FOG WILL BURN
OFF...IF AT ALL. BOTH THE HRRR AND RAP KEEP FOG AROUND FOR THE
BETTER PART OF THE DAY...AND EXPAND IT ACROSS THE REGION TONIGHT.
HAVE SIDED WITH CONS SHORT SOLUTION WHICH HAS THE FOG GRADUALLY
BURNING OFF THROUGH THE LATE MORNING HOURS. HAVE SIDED WITH COOLER
GUIDANCE FOR TODAY WITH LOWER SUN ANGLE...WEAK WINDS AND POTENTIAL
STRATUS/FOG ISSUES...HOWEVER...IF FOG IS ABLE TO CLEAR...DAY SHIFT
WILL LIKELY NEED TO RAISE HIGHS 3-5 DEGREES.
FOG POTENTIAL CONTINUES INTO TONIGHT AS SURFACE RIDGE MOVES ACROSS
THE AREA. EXPECT TEMPERATURES TO RISE AFTER MIDNIGHT AS STOUT
SOUTH/SOUTHWEST FLOW INCREASES AHEAD OF A WEAK TROUGH PASSING
THROUGH THE REGION MONDAY MORNING.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 346 AM CST SUN DEC 6 2015
MONDAY MORNING SHOULD START OUT VERY MILD AS A SOUTHERLY BREEZE
BRINGS TEMPERATURES UP QUICKLY. THE GRADIENT SLACKENS JUST A TOUCH
AND WINDS BECOME MORE WESTERLY. WITH DEEPER MIXING POTENTIAL AND A
CONTINUOUSLY DECREASING SNOW COVER HAVE OPTED TO KEEP HIGHS SIMILAR
TO PREVIOUS FORECAST...MAINLY MID 40S TO AROUND 50.
MONDAY NIGHT INTO TUESDAY WILL SEE THIS WESTERLY INFLUENCE CONTINUE
SO VERY MILD LOWS IN THE 20S TO LOWER 30S AND WENT AHEAD AND RAISED
HIGHS A BIT AS SNOW COVER WILL BE GREATLY DIMINISHED BY TUESDAY.
HAVE HIGHS FROM THE MID 40S IN THE BIG SIOUX RIVER VALLEY TO THE
LOWER 50S ALONG THE MISSOURI RIVER CORRIDOR. COULD EVEN GET CLOSER
TO 50 ALONG AND EAST OF THE BUFFALO RIDGE WITH POTENTIAL FOR
ENHANCED MIXING AND LESS SNOW COVER.
IN THE OUTER PERIODS(WEDNESDAY THROUGH SATURDAY)...FAST WESTERLY
FLOW TRANSITIONS TO DEEPER SOUTHERLY FLOW AS A TROUGH OF LOW
PRESSURE DEEPENS OVER THE ROCKIES AND MOVES ONTO THE PLAINS FRIDAY
NIGHT INTO SATURDAY. A RELATIVELY STRONG UPPER LEVEL WAVE WILL MOVE
THROUGH WEDNESDAY NIGHT INTO THURSDAY BUT THE STRONGER FORCING...AND
THUS BETTER CHANCES FOR PRECIPITATION...LOOK TO REMAIN TO THE NORTH
OF THE AREA. PRECIPITATION CHANCES BEGIN TO INCREASE FRIDAY NIGHT
INTO SATURDAY AS THE TROUGH MOVES ONTO THE PLAINS BUT THE MODELS ALL
OVER THE PLACE ON PLACEMENT SO CONFIDENCE ON JUST WHAT WILL HAPPEN
STILL A LITTLE LOW. WILL SIDE A LITTLE MORE CLOSELY TO THE ECMWF
WITH SOME WEIGHTING FROM THE GFS WHILE MOSTLY IGNORING THE GEM. THE
GEM SEEMS A BIT TOO AGGRESSIVE WITH THE WARM SECTOR FRIDAY INTO
SATURDAY...BUT WILL WATCH TRENDS AS THIS PATTERN NOT IMPOSSIBLE BUT
A LITTLE OUT OF SEASON WITH LITTLE TO NO HUDSON BAY LOW INFLUENCE
AND SUGGESTING MUCH MORE RIDGING WHICH IS PRETTY FAR NORTH FOR THIS
TIME OF YEAR. TEMPERATURES WELL ABOVE NORMAL WEDNESDAY AND
THURSDAY...STILL ABOVE NORMAL BUT NOT BY QUITE SO MUCH FRIDAY THEN
CLOSER TO NORMAL BY THE WEEKEND.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 537 AM CST SUN DEC 6 2015
LOW LYING STRATUS AND FOG SETTING UP EAST OF I-29. REALLY A TOUGH
CALL TO FIGURE OUT HOW QUICKLY STRATUS WILL BURN OFF...IF AT ALL.
FURTHER TO THE WEST...PATCHY FOG SHOULD BURN OFF THROUGH THE
MORNING HOURS. MODELS SUGGEST POTENTIAL OF FOG AND STRATUS
DEVELOPING TONIGHT...BUT WITH GUIDANCE NOT SHOWING CEILING OR
VISIBILITY RESTRICTION...HAVE LEFT MENTION OUT OF THE TAF FOR NOW.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...DENSE FOG ADVISORY UNTIL NOON CST TODAY FOR IAZ002-003-012>014-
020>022-031-032.
NE...NONE.
&&
$$
UPDATE...MJ
SHORT TERM...
LONG TERM...08
AVIATION...
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
539 AM CST SUN DEC 6 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 346 AM CST SUN DEC 6 2015
LOW CONFIDENCE TODAY IN TERMS OF SKY COVER AND TEMPERATURES.
CURRENTLY...TROUGH MOVING THROUGH THE AREA WITH FAIRLY DENSE AND
WIDESPREAD FOG AHEAD OF THE TROUGH. BEHIND THE TROUGH...PATCHY FOG
PERSISTS AND WITH WEAK WINDS AND STOUT INVERSION REMAINING ACROSS
THE AREA...QUESTIONS REMAIN AS TO HOW QUICK THE FOG WILL BURN
OFF...IF AT ALL. BOTH THE HRRR AND RAP KEEP FOG AROUND FOR THE
BETTER PART OF THE DAY...AND EXPAND IT ACROSS THE REGION TONIGHT.
HAVE SIDED WITH CONS SHORT SOLUTION WHICH HAS THE FOG GRADUALLY
BURNING OFF THROUGH THE LATE MORNING HOURS. HAVE SIDED WITH COOLER
GUIDANCE FOR TODAY WITH LOWER SUN ANGLE...WEAK WINDS AND POTENTIAL
STRATUS/FOG ISSUES...HOWEVER...IF FOG IS ABLE TO CLEAR...DAY SHIFT
WILL LIKELY NEED TO RAISE HIGHS 3-5 DEGREES.
FOG POTENTIAL CONTINUES INTO TONIGHT AS SURFACE RIDGE MOVES ACROSS
THE AREA. EXPECT TEMPERATURES TO RISE AFTER MIDNIGHT AS STOUT
SOUTH/SOUTHWEST FLOW INCREASES AHEAD OF A WEAK TROUGH PASSING
THROUGH THE REGION MONDAY MORNING.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 346 AM CST SUN DEC 6 2015
MONDAY MORNING SHOULD START OUT VERY MILD AS A SOUTHERLY BREEZE
BRINGS TEMPERATURES UP QUICKLY. THE GRADIENT SLACKENS JUST A TOUCH
AND WINDS BECOME MORE WESTERLY. WITH DEEPER MIXING POTENTIAL AND A
CONTINUOUSLY DECREASING SNOW COVER HAVE OPTED TO KEEP HIGHS SIMILAR
TO PREVIOUS FORECAST...MAINLY MID 40S TO AROUND 50.
MONDAY NIGHT INTO TUESDAY WILL SEE THIS WESTERLY INFLUENCE CONTINUE
SO VERY MILD LOWS IN THE 20S TO LOWER 30S AND WENT AHEAD AND RAISED
HIGHS A BIT AS SNOW COVER WILL BE GREATLY DIMINISHED BY TUESDAY.
HAVE HIGHS FROM THE MID 40S IN THE BIG SIOUX RIVER VALLEY TO THE
LOWER 50S ALONG THE MISSOURI RIVER CORRIDOR. COULD EVEN GET CLOSER
TO 50 ALONG AND EAST OF THE BUFFALO RIDGE WITH POTENTIAL FOR
ENHANCED MIXING AND LESS SNOW COVER.
IN THE OUTER PERIODS(WEDNESDAY THROUGH SATURDAY)...FAST WESTERLY
FLOW TRANSITIONS TO DEEPER SOUTHERLY FLOW AS A TROUGH OF LOW
PRESSURE DEEPENS OVER THE ROCKIES AND MOVES ONTO THE PLAINS FRIDAY
NIGHT INTO SATURDAY. A RELATIVELY STRONG UPPER LEVEL WAVE WILL MOVE
THROUGH WEDNESDAY NIGHT INTO THURSDAY BUT THE STRONGER FORCING...AND
THUS BETTER CHANCES FOR PRECIPITATION...LOOK TO REMAIN TO THE NORTH
OF THE AREA. PRECIPITATION CHANCES BEGIN TO INCREASE FRIDAY NIGHT
INTO SATURDAY AS THE TROUGH MOVES ONTO THE PLAINS BUT THE MODELS ALL
OVER THE PLACE ON PLACEMENT SO CONFIDENCE ON JUST WHAT WILL HAPPEN
STILL A LITTLE LOW. WILL SIDE A LITTLE MORE CLOSELY TO THE ECMWF
WITH SOME WEIGHTING FROM THE GFS WHILE MOSTLY IGNORING THE GEM. THE
GEM SEEMS A BIT TOO AGGRESSIVE WITH THE WARM SECTOR FRIDAY INTO
SATURDAY...BUT WILL WATCH TRENDS AS THIS PATTERN NOT IMPOSSIBLE BUT
A LITTLE OUT OF SEASON WITH LITTLE TO NO HUDSON BAY LOW INFLUENCE
AND SUGGESTING MUCH MORE RIDGING WHICH IS PRETTY FAR NORTH FOR THIS
TIME OF YEAR. TEMPERATURES WELL ABOVE NORMAL WEDNESDAY AND
THURSDAY...STILL ABOVE NORMAL BUT NOT BY QUITE SO MUCH FRIDAY THEN
CLOSER TO NORMAL BY THE WEEKEND.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 537 AM CST SUN DEC 6 2015
LOW LYING SATRATUS AND FOG SETTING UP EAST OF I-29. REALLY A TOUGH
CALL TO FIGURE OUT HOW QUICKLY STRATUS WILL BURN OFF...IF AT ALL.
FURTHER TO THE WEST...PATCHY FOG SHOULD BURN OFF THROUGH THE
MORNING HOURS. MODELS SUGGEST POTENTIAL OF FOG AND STRATUS
DEVELOPING TONIGHT...BUT WITH GUIDANCE NOT SHOWING CEILING OR
VISIBILITY RESTRICTION...HAVE LEFT MENTION OUT OF THE TAF FOR NOW.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
SHORT TERM...
LONG TERM...08
AVIATION...
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
951 AM PST SUN DEC 6 2015
.SYNOPSIS...SCATTERED LIGHT SHOWERS THIS MORNING WILL DISSIPATE
THROUGH THIS AFTERNOON. HIGH PRESSURE BUILDS TONIGHT THROUGH
TUESDAY WITH A RETURN TO SEASONABLY MILD AND DRY CONDITIONS. LIGHT
RAIN RETURNS IN THE NORTH BAY WEDNESDAY THEN A STRONGER COLD FRONT
WILL IMPACT THE BAY AREA THURSDAY WITH POTENTIAL FOR HEAVY RAIN
AND STRONG WINDS. UNSETTLED PATTERN FORECAST TO CONTINUE INTO NEXT
WEEKEND.
&&
.DISCUSSION...AS OF 9:34 AM PST SUNDAY...FRONTAL BOUNDARY
CURRENTLY MOVING THROUGH THE BAY AREA WITH SOME LIGHT RAINFALL
BEING REPORTED. EARLY THIS MORNING SOME SIGNIFICANT RAIN FELL UP
IN THE SONOMA HILLS WITH 1.50-1.80 INCHES AT CAZADERO AND VENADO
GAGES. THOSE REPRESENTED THE WETTEST SPOTS WHILE MANY OF THE NORTH
BAY LOWER ELEVATIONS STILL SAW TOTALS FROM 0.25-0.75. MUCH LIGHTER
AMOUNTS FROM THE GOLDEN GATE SOUTH WITH LITTLE OR NO RAIN FOR THE
SOUTH BAY. WILL UPDATE THE FORECAST GRIDS SHORTLY TO CAPTURE
LATEST TRENDS BUT TODAYS EVENT IS QUICKLY ENDING/ENDED.
ONLY CONCERN TONIGHT WILL BE OVERNIGHT/EARLY MONDAY MORNING FOG
POTENTIAL AS HIGH PRESSURE BUILDS ON TOP OF MOIST BOUNDARY LAYER.
OTHERWISE DRY AND SEASONABLY MILD MONDAY AND TUESDAY.
LOOKS LIKE WARM ADVECTION LIGHT RAINS RETURN AS EARLY AS WEDS FOR
THE NORTH BAY ONLY...IN ADVANCE OF THE THURSDAY SYSTEM.
CONFIDENCE INCREASING FOR A SIGNIFICANT SYSTEM ON THURSDAY. MODEL
TIMING HAS BEEN VERY CONSISTENT WITH 12-18Z THURSDAY FOR A STRONG
FRONTAL PASSAGE WITH STRONG JET SUPPORT AND HIGH TPW...ALONG WITH
GUSTY SURFACE WINDS. THIS STORM WILL BE THE FOCUS OVER THE NEXT
FEW DAYS. EARLY RFC QPF NUMBERS ARE SHOWING OVER 2 INCHES IN THE
NORTH BAY WITH THIS SYSTEM WITH 0.75-1.50 PAINTED BY THE 12Z GFS
FOR MUCH OF THE CWA.
SHOWERS TO LINGER FRIDAY IN COOL UNSTABLE UPPER TROUGH. CANADIAN
AND ECMWF BRING ANOTHER STRONG SYSTEM NEXT WEEKEND WHILE THE 12Z
GFS HAS TURNED DRY...WILL SEE IF THATS THE OUTLIER. 12Z ECMWF WILL
BE IN SHORTLY AND GIVE US RENEWED INTEL FOR THE AFTERNOON UPDATES.
&&
.PREV DISCUSSION...AS OF 3:25 AM PST SUNDAY...RAIN BEGAN TO SPREAD
INTO THE NORTH BAY SHORTLY AFTER MIDNIGHT AS A WEAKENING FRONTAL
BOUNDARY APPROACHED OUR COAST. THE FRONT WAS STRONG ENOUGH TO
GENERATE HEAVY RAIN JUST TO THE NORTH OF SONOMA COUNTY AT UKIAH.
BUT SATELLITE AND RADAR CURRENTLY INDICATE THE FRONT SOUTH OF
MENDOCINO COUNTY IS WEAK AND DISORGANIZED. AND...MODELS FORECAST
THE FRONT TO WEAKEN FURTHER AND DISSIPATE TODAY AS IT PRESSES
INLAND AND ENCOUNTERS THE UPPER RIDGE OVER THE WESTERN UNITED
STATES. THE NAM HAS FINALLY ADJUSTED ITS NORTH BAY QPF DOWNWARD
AND IS NOW IN LINE WITH OTHER MODELS IN FORECASTING MAX RAIN
TOTALS OF SLIGHTLY MORE THAN A HALF INCH IN NORTHERN SONOMA
COUNTY. RAIN AMOUNTS ARE EXPECTED TO TAPER OFF SIGNIFICANTLY
FURTHER SOUTH...TO LESS THAN A QUARTER OF AN INCH IN SOUTHERN NAPA
COUNTY AND SOUTHERN MARIN COUNTY...AND TO LESS THAN A TENTH OF AN
INCH SOUTH OF THE GOLDEN GATE. LATEST HRRR MODEL SHOWS
PRECIPITATION PEAKING IN THE NORTH BAY FOR A FEW HOURS PRIOR TO
SUNRISE...AND REACHING SAN FRANCISCO RIGHT AROUND SUNRISE. THE
HRRR ALSO INDICATES LITTLE OR NO RAIN REACHING SOUTH OF SAN MATEO
AND ALAMEDA COUNTIES TODAY. ALL MODELS AGREE THAT THE FRONT WILL
DISSIPATE BY MID AFTERNOON AND THAT MOST RAIN WILL END BY THEN.
DRY WEATHER IS EXPECTED TO RETURN TO ALL AREAS BY THIS EVENING.
A BROAD UPPER RIDGE OVER THE EASTERN PACIFIC ALONG 20N IS FORECAST
TO BUILD NORTH AND EAST ACROSS CENTRAL AND SOUTHERN CALIFORNIA ON
MONDAY AND TUESDAY...WITH H5 HEIGHTS FORECAST TO CLIMB PAST 586 DM
ACROSS THE SOUTHERN PORTION OF OUR CWA BY LATE TUESDAY. THIS
RIDGING WILL RESULT IN A COUPLE DAYS OF DRY AND MILD WEATHER.
HIGH TEMPS WILL BE IN THE 60S IN MOST AREAS...WITH LOWER 70S
LIKELY ACROSS PORTIONS OF MONTEREY AND SAN BENITO COUNTIES. THE
MODELS INDICATE THAT CONSIDERABLE HIGH LEVEL MOISTURE WILL MAKE
ITS WAY THROUGH THE RIDGE WHICH WILL RESULT IN PERIODS OF HIGH
CLOUDS ON MONDAY AND TUESDAY.
A MOIST WSWLY FLOW WILL DEVELOP ON THE NORTH SIDE OF THE RIDGE
EARLY IN THE WEEK AND BRING SIGNIFICANT RAIN INTO THE PACIFIC
NORTHWEST BY TUESDAY. THAT MOIST FLOW IS THEN FORECAST TO SAG AS
FAR SOUTH AS OUR NORTH BAY COUNTIES BY LATE TUESDAY NIGHT AND
WEDNESDAY. THE INITIAL WARM ADVECTION PRECIPITATION THAT DEVELOPS
IN OUR AREA IS EXPECTED TO REMAIN CONFINED TO THE NORTH BAY
THROUGH WEDNESDAY EVENING. AN UPPER TROUGH WILL THEN APPROACH THE
COAST AND DRIVE THE FRONTAL BOUNDARY AND ASSOCIATED RAINFALL
SOUTH THROUGH OUR ENTIRE FORECAST AREA LATE WEDNESDAY NIGHT AND
THURSDAY. THE TROUGH WILL DIG SOUTH AS IT MOVES INLAND...DRAWING A
COOL AND UNSTABLE AIRMASS SOUTH ACROSS CALIFORNIA...AND RESULTING
IN SCATTERED SHOWERS FROM THURSDAY NIGHT INTO FRIDAY MORNING. THIS
WEDNESDAY/THURSDAY SYSTEM IS CURRENTLY PROJECTED TO PRODUCE
RAINFALL TOTALS FROM A HALF INCH TO AN INCH AND A HALF OVER MUCH
OF OUR AREA. THIS SYSTEM COULD ALSO PRODUCE LOCALLY STRONG AND
GUSTY WINDS FROM WEDNESDAY EVENING THROUGH THURSDAY EVENING.
BOTH THE GFS AND ECMWF FORECAST A COLD SYSTEM TO SWEEP IN FROM THE
NORTHWEST NEXT WEEKEND...BRINGING ANOTHER ROUND OF WIDESPREAD
RAIN.
&&
.AVIATION...AS OF 9:50 AM PST SUNDAY...SYSTEM GOING ACROSS WILL
KEEP RAIN AND SHOWERS GOING INTO THE AFTERNOON NORTH OF MONTEREY
BAY. POTENTIAL FOR MVFR CIGS TONIGHT. WINDS MOSTLY 150 TO 180 WILL
SWITCH TO MORE 200 TO 230 AFTER 03Z. MODERATE CONFIDENCE.
VICINITY OF KSFO...RAIN FORECAST TO DIMINISH THROUGH THE DAY WITH
-RA SWITCHING TO VCSH AFTER 19Z. WINDS STARING OUT 130 TO 150 BUT
WILL SWITCH TO CLOSER TO 210 AFTER 04Z. CIGS VFR MOST OF THE DAY
EXCEPT MVFR DURING ANY RAIN. MODERATE CONFIDENCE.
SFO BRIDGE APPROACH...SIMILAR TO KSFO.
MONTEREY BAY AREA TERMINALS...VFR THROUGH THE DAY BECOMING MVFR
LATE TONIGHT AS CIGS DROP TO UNDER 020. WINDS BECOMING 240 TO 270
AFTER 20Z. -RA EXPECTED TO STAY TO THE NORTH SO REMOVED EVEN VCSH
FROM KMRY AND KSNS. MODERATE TO HIGH CONFIDENCE.
&&
.BEACHES...AS OF 4:18 AM PST SUNDAY...A STORM SYSTEM NOW PUSHING
INTO COASTAL BRITISH COLUMBIA HAS GENERATED A LARGE LONG PERIOD
WESTERLY SWELL WHICH IS EXPECTED TO REACH THE COAST LATE TONIGHT
STICKING AROUND THROUGH AT LEAST MONDAY EVENING. WAVES ASSOCIATED
WITH SYSTEM ARE EXPECTED TO REACH 17 TO 18 FEET WITH A PERIOD OF
17 TO 19 SECONDS...WITH OCCASIONAL SETS UP TO 20 FEET. THESE
HIGHLY ENERGETIC LONG PERIOD WAVES WILL PRODUCE EXCEPTIONALLY
LARGE SURF ALONG THE COAST ESPECIALLY NEAR DEEP WATER BREAKS SUCH
AS GHOST TREE...MARINA BEACH...MAVERICKS AND ALSO ALONG OCEAN
BEACH.
THESE LARGE BREAKING WAVES WILL PUSH WATER WELL UP ONTO THE BEACH
POSSIBLY WASHING PEOPLE FROM THE BEACH INTO THE SEA. LARGE SNEAKER
WAVES WILL ALSO BE POSSIBLE ON STEEP BEACHES SUCH AS CARMEL RIVER
BEACH AND MONTARA BEACH. PLEASE DO NOT CLIMB ON ROCKS OR JETTIES
ALONG THE COAST SINCE THESE AREAS WILL ALSO BE PRONE TO SNEAKER
WAVES. THESE WAVES WILL ARRIVE IN SETS WITH LONG LULLS BETWEEN
WAVE ACTIVITY WHICH COULD GIVE BEACH VISITORS A FALSE SENSE OF
SECURITY...DRAWING THEM CLOSER TO THE WATERS EDGE. REMEMBER TO
NEVER TURN YOUR BACK TO THE WATER AND ALWAYS KEEP AN EYE OUT FOR
RAPIDLY APPROACHING WAVES.
&&
.MARINE...AS OF 09:42 AM PST SUNDAY...SOUTHWESTERLY WINDS WILL
CONTINUE THROUGH THE DAY AS A STORM SYSTEM SLIDES THROUGH THE
AREA. A LARGE LONG PERIOD WESTERLY SWELL REMAINS ON TRACK TO MOVE
THROUGH THE WATERS TONIGHT...PERSISTING INTO MONDAY. THIS SWELL
WILL RESULT IN EXCESSIVELY LARGE BREAKING WAVES ALONG COASTAL
REEFS AND SAND BARS AS WELL AS ACROSS THE SAN FRANCISCO BAR.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.TDAY...SCA...PT ARENA TO PIGEON PT 10-60 NM
SCA...ROUGH BAR ADVISORY FOR SF BAR
&&
$$
PUBLIC FORECAST: RWW
AVIATION: BELL
MARINE: BELL
VISIT US AT WWW.WEATHER.GOV/SANFRANCISCO
FOLLOW US ON FACEBOOK AND TWITTER AT:
WWW.FACEBOOK.COM/NWSBAYAREA
WWW.TWITTER.COM/NWSBAYAREA
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
934 AM PST SUN DEC 6 2015
.SYNOPSIS...SCATTERED LIGHT SHOWERS THIS MORNING WILL DISSIPATE
THROUGH THIS AFTERNOON. HIGH PRESSURE BUILDS TONIGHT THROUGH
TUESDAY WITH A RETURN TO SEASONABLY MILD AND DRY CONDITIONS. LIGHT
RAIN RETURNS IN THE NORTH BAY WEDNESDAY THEN A STRONGER COLD FRONT
WILL IMPACT THE BAY AREA THURSDAY WITH POTENTIAL FOR HEAVY RAIN
AND STRONG WINDS. UNSETTLED PATTERN FORECAST TO CONTINUE INTO NEXT
WEEKEND.
&&
.DISCUSSION...AS OF 9:34 AM PST SUNDAY...FRONTAL BOUNDARY
CURRENTLY MOVING THROUGH THE BAY AREA WITH SOME LIGHT RAINFALL
BEING REPORTED. EARLY THIS MORNING SOME SIGNIFICANT RAIN FELL UP
IN THE SONOMA HILLS WITH 1.50-1.80 INCHES AT CAZADERO AND VENADO
GAGES. THOSE REPRESENTED THE WETTEST SPOTS WHILE MANY OF THE NORTH
BAY LOWER ELEVATIONS STILL SAW TOTALS FROM 0.25-0.75. MUCH LIGHTER
AMOUNTS FROM THE GOLDEN GATE SOUTH WITH LITTLE OR NO RAIN FOR THE
SOUTH BAY. WILL UPDATE THE FORECAST GRIDS SHORTLY TO CAPTURE
LATEST TRENDS BUT TODAYS EVENT IS QUICKLY ENDING/ENDED.
ONLY CONCERN TONIGHT WILL BE OVERNIGHT/EARLY MONDAY MORNING FOG
POTENTIAL AS HIGH PRESSURE BUILDS ON TOP OF MOIST BOUNDARY LAYER.
OTHERWISE DRY AND SEASONABLY MILD MONDAY AND TUESDAY.
LOOKS LIKE WARM ADVECTION LIGHT RAINS RETURN AS EARLY AS WEDS FOR
THE NORTH BAY ONLY...IN ADVANCE OF THE THURSDAY SYSTEM.
CONFIDENCE INCREASING FOR A SIGNIFICANT SYSTEM ON THURSDAY. MODEL
TIMING HAS BEEN VERY CONSISTENT WITH 12-18Z THURSDAY FOR A STRONG
FRONTAL PASSAGE WITH STRONG JET SUPPORT AND HIGH TPW...ALONG WITH
GUSTY SURFACE WINDS. THIS STORM WILL BE THE FOCUS OVER THE NEXT
FEW DAYS. EARLY RFC QPF NUMBERS ARE SHOWING OVER 2 INCHES IN THE
NORTH BAY WITH THIS SYSTEM WITH 0.75-1.50 PAINTED BY THE 12Z GFS
FOR MUCH OF THE CWA.
SHOWERS TO LINGER FRIDAY IN COOL UNSTABLE UPPER TROUGH. CANADIAN
AND ECMWF BRING ANOTHER STRONG SYSTEM NEXT WEEKEND WHILE THE 12Z
GFS HAS TURNED DRY...WILL SEE IF THATS THE OUTLIER. 12Z ECMWF WILL
BE IN SHORTLY AND GIVE US RENEWED INTEL FOR THE AFTERNOON UPDATES.
&&
.PREV DISCUSSION...AS OF 3:25 AM PST SUNDAY...RAIN BEGAN TO SPREAD
INTO THE NORTH BAY SHORTLY AFTER MIDNIGHT AS A WEAKENING FRONTAL
BOUNDARY APPROACHED OUR COAST. THE FRONT WAS STRONG ENOUGH TO
GENERATE HEAVY RAIN JUST TO THE NORTH OF SONOMA COUNTY AT UKIAH.
BUT SATELLITE AND RADAR CURRENTLY INDICATE THE FRONT SOUTH OF
MENDOCINO COUNTY IS WEAK AND DISORGANIZED. AND...MODELS FORECAST
THE FRONT TO WEAKEN FURTHER AND DISSIPATE TODAY AS IT PRESSES
INLAND AND ENCOUNTERS THE UPPER RIDGE OVER THE WESTERN UNITED
STATES. THE NAM HAS FINALLY ADJUSTED ITS NORTH BAY QPF DOWNWARD
AND IS NOW IN LINE WITH OTHER MODELS IN FORECASTING MAX RAIN
TOTALS OF SLIGHTLY MORE THAN A HALF INCH IN NORTHERN SONOMA
COUNTY. RAIN AMOUNTS ARE EXPECTED TO TAPER OFF SIGNIFICANTLY
FURTHER SOUTH...TO LESS THAN A QUARTER OF AN INCH IN SOUTHERN NAPA
COUNTY AND SOUTHERN MARIN COUNTY...AND TO LESS THAN A TENTH OF AN
INCH SOUTH OF THE GOLDEN GATE. LATEST HRRR MODEL SHOWS
PRECIPITATION PEAKING IN THE NORTH BAY FOR A FEW HOURS PRIOR TO
SUNRISE...AND REACHING SAN FRANCISCO RIGHT AROUND SUNRISE. THE
HRRR ALSO INDICATES LITTLE OR NO RAIN REACHING SOUTH OF SAN MATEO
AND ALAMEDA COUNTIES TODAY. ALL MODELS AGREE THAT THE FRONT WILL
DISSIPATE BY MID AFTERNOON AND THAT MOST RAIN WILL END BY THEN.
DRY WEATHER IS EXPECTED TO RETURN TO ALL AREAS BY THIS EVENING.
A BROAD UPPER RIDGE OVER THE EASTERN PACIFIC ALONG 20N IS FORECAST
TO BUILD NORTH AND EAST ACROSS CENTRAL AND SOUTHERN CALIFORNIA ON
MONDAY AND TUESDAY...WITH H5 HEIGHTS FORECAST TO CLIMB PAST 586 DM
ACROSS THE SOUTHERN PORTION OF OUR CWA BY LATE TUESDAY. THIS
RIDGING WILL RESULT IN A COUPLE DAYS OF DRY AND MILD WEATHER.
HIGH TEMPS WILL BE IN THE 60S IN MOST AREAS...WITH LOWER 70S
LIKELY ACROSS PORTIONS OF MONTEREY AND SAN BENITO COUNTIES. THE
MODELS INDICATE THAT CONSIDERABLE HIGH LEVEL MOISTURE WILL MAKE
ITS WAY THROUGH THE RIDGE WHICH WILL RESULT IN PERIODS OF HIGH
CLOUDS ON MONDAY AND TUESDAY.
A MOIST WSWLY FLOW WILL DEVELOP ON THE NORTH SIDE OF THE RIDGE
EARLY IN THE WEEK AND BRING SIGNIFICANT RAIN INTO THE PACIFIC
NORTHWEST BY TUESDAY. THAT MOIST FLOW IS THEN FORECAST TO SAG AS
FAR SOUTH AS OUR NORTH BAY COUNTIES BY LATE TUESDAY NIGHT AND
WEDNESDAY. THE INITIAL WARM ADVECTION PRECIPITATION THAT DEVELOPS
IN OUR AREA IS EXPECTED TO REMAIN CONFINED TO THE NORTH BAY
THROUGH WEDNESDAY EVENING. AN UPPER TROUGH WILL THEN APPROACH THE
COAST AND DRIVE THE FRONTAL BOUNDARY AND ASSOCIATED RAINFALL
SOUTH THROUGH OUR ENTIRE FORECAST AREA LATE WEDNESDAY NIGHT AND
THURSDAY. THE TROUGH WILL DIG SOUTH AS IT MOVES INLAND...DRAWING A
COOL AND UNSTABLE AIRMASS SOUTH ACROSS CALIFORNIA...AND RESULTING
IN SCATTERED SHOWERS FROM THURSDAY NIGHT INTO FRIDAY MORNING. THIS
WEDNESDAY/THURSDAY SYSTEM IS CURRENTLY PROJECTED TO PRODUCE
RAINFALL TOTALS FROM A HALF INCH TO AN INCH AND A HALF OVER MUCH
OF OUR AREA. THIS SYSTEM COULD ALSO PRODUCE LOCALLY STRONG AND
GUSTY WINDS FROM WEDNESDAY EVENING THROUGH THURSDAY EVENING.
BOTH THE GFS AND ECMWF FORECAST A COLD SYSTEM TO SWEEP IN FROM THE
NORTHWEST NEXT WEEKEND...BRINGING ANOTHER ROUND OF WIDESPREAD
RAIN.
&&
.AVIATION...AS OF 4:10 AM PST SUNDAY...THE CURRENT IR SATELLITE
IMAGE IS SHOWING A COLD FRONT PUSHING TOWARDS THE TERMINALS THIS
MORNING. KMUX DOPPLER RADAR IS INDICATING RAIN SLIDING ACROSS
SONOMA AND NAPA COUNTY`S...THIS RAIN IS EXPECTED TO SPREAD SLOWLY
SOUTH INTO THE SAN FRANCISCO BAY AREA LATER THIS MORNING. HOWEVER
THE RAIN IS NOT EXPECTED TO PUSH FARTHER SOUTH THAN SANTA CRUZ.
SURFACE WINDS WILL BE PRIMARILY OUT OF THE SOUTH SOUTHEAST TODAY
AND WILL BE GUSTY THIS MORNING AS THE FRONT PASSES BY.
VICINITY OF KSFO...VFR CONDITIONS ARE EXPECTED TO PREVAIL TODAY
WITH LIGHT RAIN BEGINNING AROUND 1400Z. MODEL GUIDANCE HASN`T
BEEN THE GREATEST WITH TODAY`S SYSTEM SO BEST GUESS AT RAIN ENDING
SHOWERS BEGINNING WILL BE AROUND 1900Z WITH SHOWERS ENDING BY
2300Z. SO FAR WINDS HAVEN`T BEEN TO IMPRESSIVE AND GUIDANCE ISN`T
GREAT TODAY SO ANTICIPATING RELATIVELY LIGHT SOUTHERLY WINDS
REACHING 8 TO 12 KT THIS MORNING WITH OCCASIONAL GUSTS TO 18 KT
THROUGH ROUGHLY 1900Z.
CONFIDENCE LOW.
SFO BRIDGE APPROACH...SIMILAR TO KSFO.
MONTEREY BAY AREA TERMINALS...VFR CONDITIONS ARE EXPECTED TO
PREVAIL TODAY WITH A FEW SHOWERS IN THE VICINITY...BEST CHANCE
NORTH OF THE TERMINALS. RELATIVELY LIGHT OFFSHORE WINDS ARE
ANTICIPATED THIS MORNING WITH THE STRONGEST REACHING 8 TO 12 KT IN
THE SALINAS VALLEY.
CONFIDENCE IS MODERATE.
&&
.BEACHES...AS OF 4:18 AM PST SUNDAY...A STORM SYSTEM NOW PUSHING
INTO COASTAL BRITISH COLUMBIA HAS GENERATED A LARGE LONG PERIOD
WESTERLY SWELL WHICH IS EXPECTED TO REACH THE COAST LATE TONIGHT
STICKING AROUND THROUGH AT LEAST MONDAY EVENING. WAVES ASSOCIATED
WITH SYSTEM ARE EXPECTED TO REACH 17 TO 18 FEET WITH A PERIOD OF
17 TO 19 SECONDS...WITH OCCASIONAL SETS UP TO 20 FEET. THESE
HIGHLY ENERGETIC LONG PERIOD WAVES WILL PRODUCE EXCEPTIONALLY
LARGE SURF ALONG THE COAST ESPECIALLY NEAR DEEP WATER BREAKS SUCH
AS GHOST TREE...MARINA BEACH...MAVERICKS AND ALSO ALONG OCEAN
BEACH.
THESE LARGE BREAKING WAVES WILL PUSH WATER WELL UP ONTO THE BEACH
POSSIBLY WASHING PEOPLE FROM THE BEACH INTO THE SEA. LARGE SNEAKER
WAVES WILL ALSO BE POSSIBLE ON STEEP BEACHES SUCH AS CARMEL RIVER
BEACH AND MONTARA BEACH. PLEASE DO NOT CLIMB ON ROCKS OR JETTIES
ALONG THE COAST SINCE THESE AREAS WILL ALSO BE PRONE TO SNEAKER
WAVES. THESE WAVES WILL ARRIVE IN SETS WITH LONG LULLS BETWEEN
WAVE ACTIVITY WHICH COULD GIVE BEACH VISITORS A FALSE SENSE OF
SECURITY...DRAWING THEM CLOSER TO THE WATERS EDGE. REMEMBER TO
NEVER TURN YOUR BACK TO THE WATER AND ALWAYS KEEP AN EYE OUT FOR
RAPIDLY APPROACHING WAVES.
&&
.MARINE...AS OF 09:11 AM PST SUNDAY...SOUTHWESTERLY WINDS WILL
CONTINUE THROUGH THE DAY AS A STORM SYSTEM SLIDES THROUGH THE
AREA. A LARGE LONG PERIOD WESTERLY SWELL REMAINS ON TRACK TO MOVE
THROUGH THE WATERS TONIGHT...PERSISTING INTO MONDAY. THIS SWELL
WILL RESULT IN EXCESSIVELY LARGE BREAKING WAVES ALONG COASTAL
REEFS AND SAND BARS AS WELL AS ACROSS THE SAN FRANCISCO BAR.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.TDAY...SCA...PT ARENA TO PIGEON PT 10-60 NM
SCA...ROUGH BAR ADVISORY FOR SF BAR
&&
$$
PUBLIC FORECAST: RWW
AVIATION: BELL
MARINE: BELL
VISIT US AT WWW.WEATHER.GOV/SANFRANCISCO
FOLLOW US ON FACEBOOK AND TWITTER AT:
WWW.FACEBOOK.COM/NWSBAYAREA
WWW.TWITTER.COM/NWSBAYAREA
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
152 PM EST SUN DEC 6 2015
.SYNOPSIS...
HIGH PRESSURE RIDGING INTO THE FORECAST AREA FROM THE NORTH WILL
WEAKEN AS A TROUGH INTENSIFIES OFF THE COAST TONIGHT. THE LOW
PRESSURE WILL MOVE NORTHEASTWARD AND FARTHER AWAY FROM THE
FORECAST AREA MONDAY. MUCH OF THE MOISTURE WITH THE COASTAL SYSTEM
WILL REMAIN EAST OF THE FORECAST AREA. PRESSURE RIDGING WILL BE
IN THE REGION TUESDAY AND WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
HIGH PRESSURE RIDGING INTO THE FORECAST AREA WILL WEAKEN. THE
TROUGHING OFF THE COAST WILL INTENSIFY IN RESPONSE TO THE
APPROACHING UPPER TROUGH. THE MODEL DEPICT THE STRONGEST UPPER-
LEVEL LIFT ASSOCIATED WITH THE RIGHT ENTRANCE REGION OF THE H25
JET DURING THE 09Z TO 12Z TIME FRAME. THE 16Z HRRR DISPLAYED
SCATTERED AREAS OF RAIN BEGINNING TO DEVELOP IN THE EAST PART OF
THE FORECAST AREA THIS EVENING. THE 12Z ARW HAD SCATTERED PATCHES
OF RAIN JUST NEARING THE EAST EDGE OF THE FORECAST AREA AROUND 06Z
WITH NEARLY ALL RAIN STAYING JUST EAST OF THE FORECAST AREA
THROUGH THE NIGHT. BASED ON THE INITIAL DRYNESS AND GREATER UPPER-
LEVEL LIFT HOLDING OFF UNTIL LATE WE LEANED TOWARD THE SLOWER
TIMING. FORECASTED CHANCE POPS IN THE EAST PART CLOSE TO THE SREF
MEAN VALUES. MORE CLOUDINESS IN THE EAST SECTION SHOULD HELP HOLD
UP TEMPERATURES TONIGHT. USED THE GUIDANCE CONSENSUS EXCEPT
FOLLOWED THE HIGHER TEMPERATURES IN THE EAST PART.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
MOISTURE ASSOCIATED WITH THE COASTAL TROUGH SHOULD BE MAINLY
CONFINED TO THE EAST PART OF THE FORECAST AREA EARLY MONDAY. THE
MODELS INDICATE UPPER-LEVEL LIFT ASSOCIATED WITH THE RIGHT
ENTRANCE REGION OF THE H25 JET SHIFTING EAST OF THE FORECAST AREA
EARLY. LEANED TOWARD THE SREF MEAN FOR THE POP FORECAST WHICH WAS
CLOSE TO NAM AND GFS MOS. THE NAM...GFS...ECMWF...AND SREF MEAN
INDICATE RAIN AMOUNTS OF 0.25 OF AN INCH OR LESS. THE MODELS SHOW
MOISTURE DIMINISHING MONDAY AFTERNOON AS THE SYSTEM SHIFTS
FARTHER NORTHEASTWARD. THE PRESSURE RIDGE MOVING INTO THE FORECAST
AREA IN THE WAKE OF THE COASTAL SYSTEM SHOULD EXTEND THROUGH THE
FORECAST AREA TUESDAY AND TUESDAY NIGHT. USED THE GUIDANCE
CONSENSUS FOR THE TEMPERATURE FORECAST EXCEPT STRONG NET
RADIATIONAL COOLING FAVORS THE COOLER GUIDANCE TUESDAY NIGHT.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
THE GFS AND ECMWF DISPLAY SURFACE RIDGING DOMINATING DURING MUCH
OF THE MEDIUM-RANGE PERIOD. THE MODELS DEPICT JUST A GLANCING
BRUSH OF THE NEXT TROUGH PROGGED TO MOVE ACROSS THE NORTHEAST PART
OF THE NATION WEDNESDAY NIGHT. THE MODELS SHOW MOST OF THE LIFT
ASSOCIATED WITH A WARM FRONT REMAINING NORTH OF THE FORECAST AREA
FRIDAY AND SATURDAY. THE MODELS INDICATE A COLD FRONT MAY BRING
SHOWERS SUNDAY. THE GFS...ECMWF...AND EKD MOS HAVE ABOVE NORMAL
TEMPERATURES THROUGH THE PERIOD.
&&
.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
SURFACE HIGH PRESSURE CURRENTLY OVER THE MID ATLANTIC AND WESTERN
CAROLINAS WILL GRADUALLY WEAKEN TONIGHT. MODELS DEPICT SOME
ISENTROPIC LIFT AND ASSOCIATED CLOUDINESS AND LIGHT RAIN TO
DEVELOP NEAR THE COAST TONIGHT...IN RESPONSE TO APPROACHING UPPER
ENERGY...AND SHIFT IT N/NE ACROSS SOUTHERN AND EASTERN PORTIONS
OF OUR FORECAST AREA...POSSIBLY INCLUDING OGB VICINITY. INCLUDED
PERIOD OF MVFR CIGS AND VCSH FOR OGB LATE TONIGHT INTO EARLY
MONDAY MORNING. THIS CLOUDINESS IS EXPECTED TO REMAIN EAST OF THE
CSRA...AGS/DNL...THOUGH OME THIN CIRRUS COULD CONTINUE TO STREAM
OVERHEAD...WITH SOME ADDITIONAL MID LEVEL CLOUDINESS WELL TO OUR
WEST POSSIBLY STREAMING IN LATE TONIGHT. HOWEVER...SOME SLIGHT
LOW LEVEL MOISTURE RECOVERY...COUPLED WITH LIGHTER WINDS AND A
PERIOD OF MOSTLY CLEAR SKIES POSSIBLE TONIGHT FOR THE
CSRA...INCLUDED A TEMPO GROUP TONIGHT FOR MVFR VSBYS AT FOG PRONE
AGS.
EXTENDED AVIATION OUTLOOK...FOG POSSIBLE AT THE FOG PRONE SITES
AGS/OGB EARLY TUESDAY MORNING. OTHERWISE...NO SIGNIFICANT IMPACTS
TO AVIATION EXPECTED THROUGH FRIDAY.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
125 PM EST SUN DEC 6 2015
.SYNOPSIS...
HIGH PRESSURE RIDGING INTO THE FORECAST AREA FROM THE NORTH WILL
WEAKEN AS A TROUGH INTENSIFIES OFF THE COAST TONIGHT. THE LOW
PRESSURE WILL MOVE NORTHEASTWARD AND FARTHER AWAY FROM THE
FORECAST AREA MONDAY. MUCH OF THE MOISTURE WITH THE COASTAL SYSTEM
WILL REMAIN EAST OF THE FORECAST AREA. PRESSURE RIDGING WILL BE
IN THE REGION TUESDAY AND WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
HIGH PRESSURE RIDGING INTO THE FORECAST AREA WILL WEAKEN. THE
TROUGHING OFF THE COAST WILL INTENSIFY IN RESPONSE TO THE
APPROACHING UPPER TROUGH. THE MODEL DEPICT THE STRONGEST UPPER-
LEVEL LIFT ASSOCIATED WITH THE RIGHT ENTRANCE REGION OF THE H25
JET DURING THE 09Z TO 12Z TIME FRAME. THE 16Z HRRR DISPLAYED
SCATTERED AREAS OF RAIN BEGINNING TO DEVELOP IN THE EAST PART OF
THE FORECAST AREA THIS EVENING. THE 12Z ARW HAD SCATTERED PATCHES
OF RAIN JUST NEARING THE EAST EDGE OF THE FORECAST AREA AROUND 06Z
WITH NEARLY ALL RAIN STAYING JUST EAST OF THE FORECAST AREA
THROUGH THE NIGHT. BASED ON THE INITIAL DRYNESS AND GREATER UPPER-
LEVEL LIFT HOLDING OFF UNTIL LATE WE LEANED TOWARD THE SLOWER
TIMING. FORECASTED CHANCE POPS IN THE EAST PART CLOSE TO THE SREF
MEAN VALUES. MORE CLOUDINESS IN THE EAST SECTION SHOULD HELP HOLD
UP TEMPERATURES TONIGHT. USED THE GUIDANCE CONSENSUS EXCEPT
FOLLOWED THE HIGHER TEMPERATURES IN THE EAST PART.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
MOISTURE ASSOCIATED WITH THE COASTAL TROUGH SHOULD BE MAINLY
CONFINED TO THE EAST PART OF THE FORECAST AREA EARLY MONDAY. THE
MODELS INDICATE UPPER-LEVEL LIFT ASSOCIATED WITH THE RIGHT
ENTRANCE REGION OF THE H25 JET SHIFTING EAST OF THE FORECAST AREA
EARLY. LEANED TOWARD THE SREF MEAN FOR THE POP FORECAST WHICH WAS
CLOSE TO NAM AND GFS MOS. THE NAM...GFS...ECMWF...AND SREF MEAN
INDICATE RAIN AMOUNTS OF 0.25 OF AN INCH OR LESS. THE MODELS SHOW
MOISTURE DIMINISHING MONDAY AFTERNOON AS THE SYSTEM SHIFTS
FARTHER NORTHEASTWARD. THE PRESSURE RIDGE MOVING INTO THE FORECAST
AREA IN THE WAKE OF THE COASTAL SYSTEM SHOULD EXTEND THROUGH THE
FORECAST AREA TUESDAY AND TUESDAY NIGHT. USED THE GUIDANCE
CONSENSUS FOR THE TEMPERATURE FORECAST EXCEPT STRONG NET
RADIATIONAL COOLING FAVORS THE COOLER GUIDANCE TUESDAY NIGHT.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
THE GFS AND ECMWF DISPLAY SURFACE RIDGING DOMINATING DURING MUCH
OF THE MEDIUM-RANGE PERIOD. THE MODELS DEPICT JUST A GLANCING
BRUSH OF THE NEXT TROUGH PROGGED TO MOVE ACROSS THE NORTHEAST PART
OF THE NATION WEDNESDAY NIGHT. THE MODELS SHOW MOST OF THE LIFT
ASSOCIATED WITH A WARM FRONT REMAINING NORTH OF THE FORECAST AREA
FRIDAY AND SATURDAY. THE MODELS INDICATE A COLD FRONT MAY BRING
SHOWERS SUNDAY. THE GFS...ECMWF...AND EKD MOS HAVE ABOVE NORMAL
TEMPERATURES THROUGH THE PERIOD.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
SURFACE HIGH PRESSURE CURRENTLY OVER THE MID ATLANTIC AND WESTERN
CAROLINAS WILL GRADUALLY WEAKEN TONIGHT. MODELS DEPICT SOME
ISENTROPIC LIFT AND ASSOCIATED CLOUDINESS AND LIGHT RAIN TO
DEVELOP NEAR THE COAST TONIGHT...IN RESPONSE TO APPROACHING UPPER
ENERGY...AND SHIFT IT N/NE ACROSS SOUTHERN AND EASTERN PORTIONS
OF OUR FORECAST AREA...POSSIBLY INCLUDING OGB VICINITY. AT THIS
TIME...KEPT MOST TERMINALS VFR...BUT INCLUDED PERIOD OF MVFR CIGS
AND VCSH FOR OGB LATE TONIGHT INTO EARLY MONDAY MORNING.
EXTENDED AVIATION OUTLOOK...FOG POSSIBLE AT THE FOG PRONE SITES
AGS/OGB EARLY TUESDAY MORNING. OTHERWISE...NO SIGNIFICANT IMPACTS
TO AVIATION EXPECTED THROUGH FRIDAY.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
&&
$$
SYNOPSIS...99
NEAR TERM...99
SHORT TERM...99
LONG TERM...99
AVIATION...99
AREA FORECAST DISCUSSION
NWS CARIBOU ME
1151 AM EST SUN DEC 6 2015
.SYNOPSIS...
HIGH PRESSURE WILL MOVE OFFSHORE TODAY. A WEAK COLD FRONT WILL
CROSS THE REGION MONDAY. HIGH PRESSURE BUILDS OVER THE AREA MONDAY
NIGHT INTO WEDNESDAY AND MOVES EAST THURSDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATED 12:50 AM: HAVE ADJUSTED TEMPERATURE AND DEW POINT BASED
ON OBSERVATIONS. ALSO ADJUSTED SKY COVER BASED ON LATEST VISIBLE
SATELLITE.
PREVIOUS DISCUSSION...
ALL FORECASTING CHALLENGES REMAIN UNDER THE SUBSIDENCE INVERSION
AND THE H925 LAYER. WILL CONTINUE TO FAVOR THE NAM12 IN NORTHERN
ZONES WITH STRATUS AND LOW STRATOCU REFORMING OR THICKENING WITH
SUNRISE AND CONTINUING THROUGH THE DAY AND INTO THE EVENING. THE
SUBSIDENCE INVERSION WILL ERODE STEADILY AS THE UPPER RIDGE MOVES
EAST TODAY AND TONIGHT...BUT WILL REMAIN IN PLACE. WEAK
DOWNSLOPING WILL GENERATE SOME HOLES IN THE STRATOCU TONIGHT...BUT
WILL LEAN TOWARDS CLOUDY SKIES FOR THESE NORTHERN ZONES.
FOR BANGOR AND DOWN EAST...THE LOW STRATOCU IS NOT EXPECTED TO BE
A FACTOR. IN ITS PLACE...FOG AND FREEZING FOG WILL BE THE ISSUES
THIS MORNING. FOLLOWING THE RAP AND HRRR GUIDANCE...FREEZING FOG
WILL BOTH FORM AND ADVECT EASTWARD FROM ITS CURRENT POSITION IN
THE MIDCOAST. THIS FOG IS ANTICIPATED TO AFFECT BANGOR AND DOWN
EAST THROUGH THE MORNING AND POTENTIALLY INTO THE EARLY AFTERNOON.
FOG THIS MORNING WILL ALSO EXTEND UP THE PENOBSCOT RIVER VALLEY
TOWARDS HOULTON. THE FREEZING FOG WILL GENERATE SOME VERY SLICK
ROADS. WILL MAINTAIN THE SPECIAL WEATHER STATEMENT HIGHLIGHTING
THIS RISK THROUGH 8AM AND MAY EXTEND IT. THE SPECIAL WEATHER
STATEMENT IS IN EFFECT FOR THE ENTIRE FORECAST AREA AS MOISTURE
THAT HAS REFROZEN AFTER YESTERDAY`S SNOWMELT IS ALSO CAUSING
HAZARDOUS DRIVING CONDITIONS.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
SFC BNDRY WL BE LOCATED ALONG THE COAST BY THE START OF THE SHORT
TERM. WL TAKE AWHILE FOR SUBSIDENCE INVERSION TO MIX OUT WITH CLDY
CONDS EXPECTED MON MRNG OVR FAR NRN ZONES. FURTHER TO THE SOUTH
EXPECT ANOTHER MOSUNNY DAY WITH TEMPS ABV NORMAL ONCE AGAIN. MAXES
WL BE A FEW DEGREES COOLER THAN SUNDAY`S HIGHS AS H9 CLD ADVECTION
KICKS IN FOLLOWING FROPA. STILL CANNOT RULE OUT A FLURRY BEING WRUNG
OUT IN NW FLOW AS VORT MAX SCOOTS ACRS WITH UPR TROF DRG THE AFTN.
NW FLOW CONTINUES DRG THE OVRNGT HRS WITH PCLDY SKIES EXPECTED ALL
NIGHT ACRS THE NORTH WITH SOME CLRNG ACRS SRN ZONES. WINDS WL BEGIN
TO DROP OFF IN THE NORTH WOODS LATE AS HIPRES BUILDS IN FM THE WEST.
SFC RIDGE AXIS WL BE ACRS CWA DRG THE DAY TUESDAY. H5 TROF CURRENTLY
OVR THE CENTER OF THE NATION WL SWING EAST AND OFF THE MID-ATLANTIC
COAST MON NGT, WITH SFC LOW DVLPNG OFF THE CAROLINA COAST. MODELS
HV TRENDED FURTHER SOUTH AND EAST WITH THIS LOW THUS NOT EXPECTING
ANY IMPACT ON CWA BY TUESDAY OTHER THAN HIGH CLDS AND INCREASE IN
WV HEIGHTS FOR MARINE ZONES.
HIPRES WL SHIFT EAST TUE NIGHT WITH RETURN FLOW BRINGING CLDS BACK
TO THE AREA. MIN TEMPS WL BE SIMILAR TO MON NGT TEMPS WITH CLDY
SKIES AND MINIMAL WARM ADVECTION.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
TEMPS WL MODERATE THROUGHOUT THE LONG TERM AS SRLY FLOW WL
PREDOMINATE THRU THURSDAY. 00Z GFS AND EC HV ANOTHER TROF EXITING
THE MID-ATLANTIC COAST THUR MRNG WITH SFC LOW EJECTING NR THE
VIRGINIA CAPES AT THIS TIME. GFS IS FURTHER NORTH WITH TRACK OF
LOW THAN EC IS WHILE GEM DOES NOT HV ANY INDICATION OF FEATURE
EITHER AT SFC OR ALOFT. THIS LOOKS TO BE THE NEXT POTENTIAL WX-
MAKER TO WATCH THRU THE PD AS RMNDR OF EXTNDD LOOKS QUIET AND
WARM, RELATIVELY SPEAKING.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
NEAR TERM: FOG IS EXPECTED TO MOVE ACROSS THE DOWN EAST REGION
THIS MORNING...BRUSHING BGR AND LINGERING IN BHB THROUGH THE
MORNING AND POSSIBLY LONGER. FREEZING FOG IS ALSO AN ISSUE THIS
MORNING AT HUL AND FVE. THE FOG WILL LIFT TO MVFR CIGS THIS
MORNING. ALL SITES NORTH OF HUL WILL HAVE MVFR CIGS MUCH OF SUNDAY
AND INTO THE EVENING.
SHORT TERM: MVFR CIGS EXPECTED OVER NORTHERN TERMINALS ON MONDAY
THEN BECOMING VFR. ANOTHER CHC FOR MVFR RESTRICTIONS ON WED NGT
AND THU.
&&
.MARINE...
NEAR TERM: A FEW GUSTS MAY REACH NEAR 25 KTS TODAY AND THIS
EVENING...BUT DO NOT BELIEVE THE PROBABILITY AND FREQUENCY OF
THESE GUSTS WARRANTS A SMALL CRAFT ADVISORY.
SHORT TERM: SEAS AND WINDS SHOULD REMAIN UNDER SCA LEVELS THROUGH
THE PERIOD.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...MIGNONE
MARINE...MIGNONE
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
406 PM EST SUN DEC 6 2015
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 405 PM EST SUN DEC 6 2015
WV IMAGERY AND RAP ANALYSIS INDICATED A SPLIT FLOW PATTERN ACROSS
NORTH AMERICA WITH A SRN STREAM MID LEVEL LOW OVER ILLINOIS AND THE
ACTIVE PORTION OF THE NRN STREAM BRANCH WELL TO THE NORTH THROUGH
NRN ONTARIO AND JAMES BAY. THE NRN ONTARIO SHRTWV HAS DRAGGED A WEAK
COLD FRONT THROUGH THE NRN LAKES WITH DRIER AIR AND ACYC COMBINED
WITH DAYTIME MIXING HELPING TO SCOUR OUT THE LOW CLOUDS OVER MUCH OF
UPPER MICHIGAN...EXCEPT OVER THE KEWEENAW AND THE EAST.
TONIGHT...THE MODELS SHOW MID LEVEL AND SFC RIDGING BUILDING INTO
THE WRN LAKES TONIGHT WITH PWAT VALUES DROPPING AOB 0.25 INCH OVER
MUCH OF UPPER MICHIGAN. ALTHOUGH THERE MAY BE A PERIOD OF CLEARING
INTO THIS EVENING...EXPECT THAT WITH FAVORABLE RADIATIONAL COOLING
CONDITIONS AND LINGERING LOW LEVEL MOISTURE WITH DEWPOINTS FROM LATE
AFTERNOON IN THE LOWER 30S...AREAS OF FOG WILL DEVELOP. ISOLD DENSE
FOG WILL ALSO BE POSSIBLE...BUT CONFIDENCE IN TIMING/LOCATIONS IS
NOT AS HIGH. DEVELOPING DOWNSLOPE SSW LOW LEVEL FLOW OVER THE WEST
WILL LIMIT FOG POTENTIAL IN THE WEST HALF NEAR LAKE SUPERIOR.
MONDAY...HIGHER RES MODELS 925MB RH FCST SUGGESTS THAT ADDITIONAL SW
FLOW DRY ADVECTION ALONG WITH LIMITED WINTER TIME DAYTIME WILL BE
ENOUGH TO AGAIN SCOUR OUT ANY LEFTOVER CLOUDS/FOG DURING THE MORNING.
THIS SHOULD ALLOW TEMPS TO CLIMB INTO THE LOW TO MID 40S WITH UPPER
40S WITH DOWNSLOPE FLOW NEAR LAKE SUPERIOR.
&&
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 326 PM EST SUN DEC 6 2015
MUCH OF THIS PERIOD WILL BE MARKED BY 500MB WAVES IN WHAT GENERALLY
LOOKS LIKE ZONAL FLOW...WITH A SERIES OF WEAK SFC LOWS SPINNING
ACROSS CANADA IMPACTING THE UPPER GREAT LAKES THROUGH THE WORK WEEK.
OVERALL LIGHT PRECIP IS ANTICIPATED.
BY 00Z TUESDAY THE INITIAL 500MB TROUGH WILL BE WELL TO OUR E /OVER
PA/...WITH AN EXITING RIDGE OVER THE UPPER GREAT LAKES AHEAD OF THE
NEXT TROUGH SET UP FROM N MANITOBA THROUGH MN/IA. A BROAD SFC LOW
WAS OVER MUCH OF W AND CENTRAL CANADA. THE E LOBE OF THIS TROUGH
WILL BE ACROSS N ONTARIO...DROPPING A COLD FRONT ACROSS OUR AREA.
THE RESULT WILL BE INCREASED MID AND HIGH CLOUDS THAT WILL CONTINUE
INTO EARLY WEDNESDAY MORNING. WHILE FCST MODELS DO INDICATE SOME
CHANCE OF PRECIPITATION...MUCH OF THAT IS LIGHT AND OVER THE E HALF
OF THE CWA. THERE WILL BE AS AN ADDITIONAL TROUGH IN THE BROAD
CANADIAN LOW SWINGS ACROSS S MANITOBA/ND TUESDAY AFTERNOON AND OVER
THE UPPER GREAT LAKES WEDNESDAY MORNING.
ZONAL FLOW/SLIGHT RIDGING BRIEFLY TAKES HOLD LATE WEDNESDAY
AFTERNOON INTO WEDNESDAY EVENING...WHILE THE NEXT 500MB TROUGH SETS
UP OVER S SASKATCHEWAN/MT. THE LAST AND STRONGEST PART OF THE
CANADIAN LOW WILL BE OVER S CENTRAL CANADA AT 06Z THURSDAY. LOOK FOR
THIS LOW TO SHIFT ACROSS N MN THURSDAY MORNING AND THEN ACROSS N
LAKE SUPERIOR/ONTARIO THURSDAY EVENING. THE LOW WILL CONTINUE TO
TRACK TO AROUND JAMES BAY BY 18Z FRIDAY. THERE ARE SOME
DISCREPANCIES...AS THE GFS AND CANADIAN RUNS EJECT THE LOW TO THE NE
MUCH QUICKER THAN THE 00Z RUN OF THE ECMWF FRIDAY NIGHT. THE 12Z
ECMWF SPED THE SYSTEM UP A BIT...BUT IT/S STILL ON THE SLOW SIDE.
JUST HOW MUCH MOISTURE WILL BE ABLE TO SURGE N INTO OUR AREA IS ALSO
IN QUESTION. THE SLOWER ECMWF GIVES MORE TIME FOR MOISTURE TO POOL
TO OUR S...AND MOVE OVERHEAD THURSDAY NIGHT. THE RESULT IS LOWER
THAN AVERAGE CONFIDENCE IN THE ONGOING FCST FROM FRIDAY ON.
A MORE ROBUST SYSTEM SHOULD SET UP OVER THE W HALF OF THE NATION
SATURDAY...IN THE FORM OF A SIGNIFICANT 500MB TROUGH. EXACTLY WHERE
THE SFC LOW SETS UP IS STILL A CONCERN AS THE 00Z RUN OF THE ECMWF
TIES IT TO THE SLOWER LOW IMPACTING OUR WEATHER THURSDAY INTO EARLY
FRIDAY. THE 12Z ECMWF SETS UP THE SECONDARY LOW WELL TO THE S. THE
GFS ON THE OTHER HAND HAS A STRONGER SFC LOW OVER THE CENTRAL PLAINS
AT 00Z SATURDAY MOVING ACROSS OUR AREA SATURDAY NIGHT. THE RESULT IS
MUCH MORE QPF OFF THE GFS...WHILE THE ECMWF PUSHES THE SWATH OF
HIGHEST PRECIP OVER LOWER MI SATURDAY NIGHT. EITHER WAY...COLD AIR
LOOKS POISED TO SLIDE IN FOR THE END OF THE WEEKEND WITH 850MB TEMPS
OF -5 TO -12C BY 00Z MONDAY ON W TO NNW WINDS. RIGHT NOW IT LOOKS
LIKE WE WILL AT LEAST TEMPORARILY BREAK OUR TREND OF ABOVE NORMAL
TEMPERATURES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1242 PM EST SUN DEC 6 2015
LOW LEVEL MOISTURE MOVING IN FROM THE SW HAD LOWERED IWD/CMX CIGS TO
IFR THIS MORNING. HOWEVER...LIMITED DAYTIME/HEATING MIXING HAS
BROUGHT CIGS BACK JUST ABOVE IFR THRESHOLD. A DOWNSLOPE COMPONENT TO
LOW LEVEL FLOW INTO SAW HAS MAINTAINED VFR CIGS THAT WERE NEAR MVFR.
EXPECT LEVEL OF EARLY AFTERNOON CIGS TO PERSIST UNTIL AROUND 21Z. THE
ARRIVAL OF A HIGH PRES RIDGE ALONG WITH DRIER AIR SHOULD HELP REDUCE
LOW CLOUDS LATER TODAY. BUT MORE FOG AND SOME LOW CLOUDSS MAY
REDEVELOP TONIGHT WITH LIGHT WINDS UNDER MOSTLY CLEAR SKIES. THE BEST
CHANCE FOR ANY FOG TO DEVELOP WILL BE AT SAW...SO FCST PREDOMINANT
IFR VSBY THERE AFT 07Z. NOT OUT OF THE QUESTION FOG COULD REDUCE VSBY
AT CMX/IWD BUT CONFIDENCE IS LOWER.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 405 PM EST SUN DEC 6 2015
THE PRES GRADIENT WILL INCREASE MON NIGHT WITH THE RIDGE SLIDING TO
THE EAST AND LOW PRES MOVING INTO NW ONTARIO. THIS WILL SUPPORT A
PERIOD OF 25 KNOT WINDS. ANOTHER PERIOD OF SRLY 25 KNOT WINDS IS
EXPECTED THU AHEAD OF LOW PRES MOVING INTO THE UPPER MS VALLEY.
OTHERWISE...WINDS WILL REMAIN BELOW 25 KNOTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KF
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
326 PM EST SUN DEC 6 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 436 AM EST SUN DEC 6 2015
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A SPLIT FLOW ACRS
NAMERICA DOWNWIND OF A DEEPER TROF OFF THE W COAST WITH A NEARLY
ZONAL NRN BRANCH FLOW OVER SRN CANADA AND THE SRN BRANCH FLOW IN THE
CONUS. A SHRTWV IN THE NRN BRANCH FLOW IS OVER NRN MANITOBA EARLY
THIS MRNG...WITH ASSOCIATED SFC LO NEAR THE SW EDGE OF HUDSON BAY. A
RATHER WEAK ATTENDANT SFC COLD FNT EXTENDS SWWD INTO MN. THE AIRMASS
BEHIND THE FNT IS PACIFIC IN ORIGIN...WITH 00Z H85 TEMPS NO LOWER
THAN 0-2C FM LK WINNIPEG INTO THE NRN PLAINS. THE TRAILING AIRMASS
IS QUITE DRY PER THE 00Z BISMARCK RAOB...WHERE THE PWAT WAS ONLY
0.25 INCH AT 00Z. THE PASSAGE OF STRONGER DYNAMIC FORCING IN CANADA
CLOSER TO NRN SHRTWV AND VERY DRY PREFRONTAL AIRMASS SHOWN ON THE
00Z GRB RAOB WITH DEEPER MSTR INFLOW TO THE N INTERRUPTED BY STRONG
SRN BRANCH DISTURBANCE MOVING INTO THE MID MS RIVER VALLEY IS
PREVENTING MUCH IF ANY PCPN AHEAD OF THIS APRCHG COLD FNT.
HOWEVER...THERE IS A GOOD OF LO CLD AHEAD OF THE FNT...AND THIS LO
CLD IS MOVING INTO THE WRN CWA. COMBINATION OF STEADY SW WINDS UNDER
SHARPER PRES GRADIENT BTWN THE APRCHG FNT AND HI PRES IN THE MID
ATLANTIC AND A GOOD DEAL OF HI CLDS OVER THE ENTIRE CWA/LO CLDS
MOVING INTO THE W IS LEADING TO WELL ABOVE NORMAL TEMPS OVER UPR
MI...WITH EARLY MRNG TEMPS GENERALLY 35 TO 40.
MAIN FCST CONCERNS IN THE SHORT TERM FOCUS ON SLIM PCPN CHCS/CLD
TRENDS ASSOCIATED WITH APRCHG COLD FNT. FOCUS FOR TNGT WL SHIFT TO
TEMPS AS DRIER AIRMASS BEHIND THE FNT PUSHES INTO THE UPR LKS.
TODAY...NRN BRANCH SHRTWV/SFC LO PRES ARE PROGGED TO CONTINUE TO THE
E...WITH ATTENDANT COLD FNT CROSSING UPR MI AND REACHING NEWBERRY
LATE IN THE AFTN. SINCE THE SHARPER UPR FORCING WL REMAIN TO THE N
AND S OF UPR MI...FCST SDNGS SHOW GENERALLY DRY MID LVLS BTWN HI
CLDS AND SHALLOW HIER RH ASSOCIATED WITH THE MORE ABUNDANT LO
CLDS...THERE HAVE NO PCPN REPORTS UPSTREAM...AND JUST A FEW OF EVEN
THE HIER RES MODELS GENERATE ANY PCPN OVER THE CWA...OPTED TO REMOVE
POPS EXCEPT FOR SOME SCHC POPS OVER LK SUP. DRIER MID LVL AIR IS
FCST TO FOLLOW DURING THE AFTN...BUT LO CLDS ARE LIKELY TO LINGER A
BIT LONGER WITH LO SUN ANGLE/LINGERING LLVL MSTR. SINCE HIER RES
MODEL FCST H95-9 RH HAS A PRETTY GOOD HANDLE ON THE LO CLD COVERAGE
EARLY THIS MRNG... UTILIZED THIS FCST FIELD TO HANDLE CLD TRENDS IN
THE GRIDS. THESE MODELS SHOW LO CLDS CLRG THE NW HALF OF THE CWA BY
00Z MON WITH ARRIVAL OF DRIER AIRMASS IN THE NRN PLAINS. AFTER THESE
LO CLDS ARRIVE BY 15Z OVER THE SE CWA...WL RETAIN THAT SKY COVER
OVER THE SE HALF THRU 00Z.
TNGT...LINGERING LO CLDS OVER THE SE CWA WL CLR THIS EVNG WITH
ARRIVAL OF THE DRIER AIR/PWAT AOB 0.25 INCH/SFC HI PRES RDG. WITH
LGT WINDS/MOCLR SKIES...TENDED TOWARD THE LO END OF GUIDANCE FOR MIN
TEMPS EVEN THOUGH SOME HI CLDS MAY ARRIVE LATER. RETAINED MENTION OF
SOME PATCHY GROUND FOG AS WELL WITH THE EXPECTED FVRBL RADIATIONAL
COOLING CONDITIONS.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 326 PM EST SUN DEC 6 2015
MUCH OF THIS PERIOD WILL BE MARKED BY 500MB WAVES IN WHAT GENERALLY
LOOKS LIKE ZONAL FLOW...WITH A SERIES OF WEAK SFC LOWS SPINNING
ACROSS CANADA IMPACTING THE UPPER GREAT LAKES THROUGH THE WORK WEEK.
OVERALL LIGHT PRECIP IS ANTICIPATED.
BY 00Z TUESDAY THE INITIAL 500MB TROUGH WILL BE WELL TO OUR E /OVER
PA/...WITH AN EXITING RIDGE OVER THE UPPER GREAT LAKES AHEAD OF THE
NEXT TROUGH SET UP FROM N MANITOBA THROUGH MN/IA. A BROAD SFC LOW
WAS OVER MUCH OF W AND CENTRAL CANADA. THE E LOBE OF THIS TROUGH
WILL BE ACROSS N ONTARIO...DROPPING A COLD FRONT ACROSS OUR AREA.
THE RESULT WILL BE INCREASED MID AND HIGH CLOUDS THAT WILL CONTINUE
INTO EARLY WEDNESDAY MORNING. WHILE FCST MODELS DO INDICATE SOME
CHANCE OF PRECIPITATION...MUCH OF THAT IS LIGHT AND OVER THE E HALF
OF THE CWA. THERE WILL BE AS AN ADDITIONAL TROUGH IN THE BROAD
CANADIAN LOW SWINGS ACROSS S MANITOBA/ND TUESDAY AFTERNOON AND OVER
THE UPPER GREAT LAKES WEDNESDAY MORNING.
ZONAL FLOW/SLIGHT RIDGING BRIEFLY TAKES HOLD LATE WEDNESDAY
AFTERNOON INTO WEDNESDAY EVENING...WHILE THE NEXT 500MB TROUGH SETS
UP OVER S SASKATCHEWAN/MT. THE LAST AND STRONGEST PART OF THE
CANADIAN LOW WILL BE OVER S CENTRAL CANADA AT 06Z THURSDAY. LOOK FOR
THIS LOW TO SHIFT ACROSS N MN THURSDAY MORNING AND THEN ACROSS N
LAKE SUPERIOR/ONTARIO THURSDAY EVENING. THE LOW WILL CONTINUE TO
TRACK TO AROUND JAMES BAY BY 18Z FRIDAY. THERE ARE SOME
DISCREPANCIES...AS THE GFS AND CANADIAN RUNS EJECT THE LOW TO THE NE
MUCH QUICKER THAN THE 00Z RUN OF THE ECMWF FRIDAY NIGHT. THE 12Z
ECMWF SPED THE SYSTEM UP A BIT...BUT IT/S STILL ON THE SLOW SIDE.
JUST HOW MUCH MOISTURE WILL BE ABLE TO SURGE N INTO OUR AREA IS ALSO
IN QUESTION. THE SLOWER ECMWF GIVES MORE TIME FOR MOISTURE TO POOL
TO OUR S...AND MOVE OVERHEAD THURSDAY NIGHT. THE RESULT IS LOWER
THAN AVERAGE CONFIDENCE IN THE ONGOING FCST FROM FRIDAY ON.
A MORE ROBUST SYSTEM SHOULD SET UP OVER THE W HALF OF THE NATION
SATURDAY...IN THE FORM OF A SIGNIFICANT 500MB TROUGH. EXACTLY WHERE
THE SFC LOW SETS UP IS STILL A CONCERN AS THE 00Z RUN OF THE ECMWF
TIES IT TO THE SLOWER LOW IMPACTING OUR WEATHER THURSDAY INTO EARLY
FRIDAY. THE 12Z ECMWF SETS UP THE SECONDARY LOW WELL TO THE S. THE
GFS ON THE OTHER HAND HAS A STRONGER SFC LOW OVER THE CENTRAL PLAINS
AT 00Z SATURDAY MOVING ACROSS OUR AREA SATURDAY NIGHT. THE RESULT IS
MUCH MORE QPF OFF THE GFS...WHILE THE ECMWF PUSHES THE SWATH OF
HIGHEST PRECIP OVER LOWER MI SATURDAY NIGHT. EITHER WAY...COLD AIR
LOOKS POISED TO SLIDE IN FOR THE END OF THE WEEKEND WITH 850MB TEMPS
OF -5 TO -12C BY 00Z MONDAY ON W TO NNW WINDS. RIGHT NOW IT LOOKS
LIKE WE WILL AT LEAST TEMPORARILY BREAK OUR TREND OF ABOVE NORMAL
TEMPERATURES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1242 PM EST SUN DEC 6 2015
LOW LEVEL MOISTURE MOVING IN FROM THE SW HAD LOWERED IWD/CMX CIGS TO
IFR THIS MORNING. HOWEVER...LIMITED DAYTIME/HEATING MIXING HAS
BROUGHT CIGS BACK JUST ABOVE IFR THRESHOLD. A DOWNSLOPE COMPONENT TO
LOW LEVEL FLOW INTO SAW HAS MAINTAINED VFR CIGS THAT WERE NEAR MVFR.
EXPECT LEVEL OF EARLY AFTERNOON CIGS TO PERSIST UNTIL AROUND 21Z. THE
ARRIVAL OF A HIGH PRES RIDGE ALONG WITH DRIER AIR SHOULD HELP REDUCE
LOW CLOUDS LATER TODAY. BUT MORE FOG AND SOME LOW CLOUDSS MAY
REDEVELOP TONIGHT WITH LIGHT WINDS UNDER MOSTLY CLEAR SKIES. THE BEST
CHANCE FOR ANY FOG TO DEVELOP WILL BE AT SAW...SO FCST PREDOMINANT
IFR VSBY THERE AFT 07Z. NOT OUT OF THE QUESTION FOG COULD REDUCE VSBY
AT CMX/IWD BUT CONFIDENCE IS LOWER.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 258 AM EST SUN DEC 6 2015
EXPECT SW WINDS TO DIMINISH TODAY AS THE PRESSURE GRADIENT
WEAKENS...REMAINING LESS THAN 25 KTS THROUGH THE REST OF THE
FORECAST PERIOD.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...KF
AVIATION...JLB
MARINE...TITUS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1244 PM EST SUN DEC 6 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 436 AM EST SUN DEC 6 2015
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A SPLIT FLOW ACRS
NAMERICA DOWNWIND OF A DEEPER TROF OFF THE W COAST WITH A NEARLY
ZONAL NRN BRANCH FLOW OVER SRN CANADA AND THE SRN BRANCH FLOW IN THE
CONUS. A SHRTWV IN THE NRN BRANCH FLOW IS OVER NRN MANITOBA EARLY
THIS MRNG...WITH ASSOCIATED SFC LO NEAR THE SW EDGE OF HUDSON BAY. A
RATHER WEAK ATTENDANT SFC COLD FNT EXTENDS SWWD INTO MN. THE AIRMASS
BEHIND THE FNT IS PACIFIC IN ORIGIN...WITH 00Z H85 TEMPS NO LOWER
THAN 0-2C FM LK WINNIPEG INTO THE NRN PLAINS. THE TRAILING AIRMASS
IS QUITE DRY PER THE 00Z BISMARCK RAOB...WHERE THE PWAT WAS ONLY
0.25 INCH AT 00Z. THE PASSAGE OF STRONGER DYNAMIC FORCING IN CANADA
CLOSER TO NRN SHRTWV AND VERY DRY PREFRONTAL AIRMASS SHOWN ON THE
00Z GRB RAOB WITH DEEPER MSTR INFLOW TO THE N INTERRUPTED BY STRONG
SRN BRANCH DISTURBANCE MOVING INTO THE MID MS RIVER VALLEY IS
PREVENTING MUCH IF ANY PCPN AHEAD OF THIS APRCHG COLD FNT.
HOWEVER...THERE IS A GOOD OF LO CLD AHEAD OF THE FNT...AND THIS LO
CLD IS MOVING INTO THE WRN CWA. COMBINATION OF STEADY SW WINDS UNDER
SHARPER PRES GRADIENT BTWN THE APRCHG FNT AND HI PRES IN THE MID
ATLANTIC AND A GOOD DEAL OF HI CLDS OVER THE ENTIRE CWA/LO CLDS
MOVING INTO THE W IS LEADING TO WELL ABOVE NORMAL TEMPS OVER UPR
MI...WITH EARLY MRNG TEMPS GENERALLY 35 TO 40.
MAIN FCST CONCERNS IN THE SHORT TERM FOCUS ON SLIM PCPN CHCS/CLD
TRENDS ASSOCIATED WITH APRCHG COLD FNT. FOCUS FOR TNGT WL SHIFT TO
TEMPS AS DRIER AIRMASS BEHIND THE FNT PUSHES INTO THE UPR LKS.
TODAY...NRN BRANCH SHRTWV/SFC LO PRES ARE PROGGED TO CONTINUE TO THE
E...WITH ATTENDANT COLD FNT CROSSING UPR MI AND REACHING NEWBERRY
LATE IN THE AFTN. SINCE THE SHARPER UPR FORCING WL REMAIN TO THE N
AND S OF UPR MI...FCST SDNGS SHOW GENERALLY DRY MID LVLS BTWN HI
CLDS AND SHALLOW HIER RH ASSOCIATED WITH THE MORE ABUNDANT LO
CLDS...THERE HAVE NO PCPN REPORTS UPSTREAM...AND JUST A FEW OF EVEN
THE HIER RES MODELS GENERATE ANY PCPN OVER THE CWA...OPTED TO REMOVE
POPS EXCEPT FOR SOME SCHC POPS OVER LK SUP. DRIER MID LVL AIR IS
FCST TO FOLLOW DURING THE AFTN...BUT LO CLDS ARE LIKELY TO LINGER A
BIT LONGER WITH LO SUN ANGLE/LINGERING LLVL MSTR. SINCE HIER RES
MODEL FCST H95-9 RH HAS A PRETTY GOOD HANDLE ON THE LO CLD COVERAGE
EARLY THIS MRNG... UTILIZED THIS FCST FIELD TO HANDLE CLD TRENDS IN
THE GRIDS. THESE MODELS SHOW LO CLDS CLRG THE NW HALF OF THE CWA BY
00Z MON WITH ARRIVAL OF DRIER AIRMASS IN THE NRN PLAINS. AFTER THESE
LO CLDS ARRIVE BY 15Z OVER THE SE CWA...WL RETAIN THAT SKY COVER
OVER THE SE HALF THRU 00Z.
TNGT...LINGERING LO CLDS OVER THE SE CWA WL CLR THIS EVNG WITH
ARRIVAL OF THE DRIER AIR/PWAT AOB 0.25 INCH/SFC HI PRES RDG. WITH
LGT WINDS/MOCLR SKIES...TENDED TOWARD THE LO END OF GUIDANCE FOR MIN
TEMPS EVEN THOUGH SOME HI CLDS MAY ARRIVE LATER. RETAINED MENTION OF
SOME PATCHY GROUND FOG AS WELL WITH THE EXPECTED FVRBL RADIATIONAL
COOLING CONDITIONS.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 258 AM EST SUN DEC 6 2015
MON LOOKS TO BE THE QUIETEST DAY AS AN UPPER RIDGE PASSES OVERHEAD.
SHOULD SEE HIGHS IN THE 40S.
FORECAST FOR MON NIGHT THROUGH NEXT WEEKEND IS UNCERTAIN AS SEVERAL
SHORTWAVES MOVE THROUGH OR NEAR THE REGION...LEADING TO MAINLY LIGHT
PRECIP AT TIMES. MON NIGHT INTO TUE MORNING COULD SEE SOME VERY
MINIMAL RAIN AND POSSIBLY SOME SNOW...BUT DEFINITELY LOW CHANCES.
TUE NIGHT INTO WED MORNING COULD SEE SOME RAIN/SNOW AS A STRONGER
SHORTWAVE MOVES THROUGH THE REGION...BUT THAT WILL DEPEND ON
TRACK/STRENGTH DETAILS. THE ECMWF IS MOSTLY DRY DURING THE PERIOD
(EXCEPT FOR SOME VERY LIGHT LAKE ENHANCEMENT OVER THE E)...BUT THE
GFS AND NAM SHOW SOME GREATER PRECIP AMOUNTS (BUT STILL FAIRLY
MINOR). MODELS SHOW POTENTIAL FOR A STRONGER SYSTEM POSSIBLY LATE
THIS WEEK AND MAYBE ANOTHER STRONGER SYSTEM OVER THE WEEKEND...BUT
CONFIDENCE IS QUITE LOW. MODELS HINT AT COLDER AIR MOVING IN WITH
AND BEHIND THOSE STRONGER SYSTEMS...IF THEY MATERIALIZE.
OTHERWISE...TEMPS WILL CONTINUE TO BE WELL ABOVE NORMAL.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1242 PM EST SUN DEC 6 2015
LOW LEVEL MOISTURE MOVING IN FROM THE SW HAD LOWERED IWD/CMX CIGS TO
IFR THIS MORNING. HOWEVER...LIMITED DAYTIME/HEATING MIXING HAS
BROUGHT CIGS BACK JUST ABOVE IFR THRESHOLD. A DOWNSLOPE COMPONENT TO
LOW LEVEL FLOW INTO SAW HAS MAINTAINED VFR CIGS THAT WERE NEAR MVFR.
EXPECT LEVEL OF EARLY AFTERNOON CIGS TO PERSIST UNTIL AROUND 21Z. THE
ARRIVAL OF A HIGH PRES RIDGE ALONG WITH DRIER AIR SHOULD HELP REDUCE
LOW CLOUDS LATER TODAY. BUT MORE FOG AND SOME LOW CLOUDSS MAY
REDEVELOP TONIGHT WITH LIGHT WINDS UNDER MOSTLY CLEAR SKIES. THE BEST
CHANCE FOR ANY FOG TO DEVELOP WILL BE AT SAW...SO FCST PREDOMINANT
IFR VSBY THERE AFT 07Z. NOT OUT OF THE QUESTION FOG COULD REDUCE VSBY
AT CMX/IWD BUT CONFIDENCE IS LOWER.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 258 AM EST SUN DEC 6 2015
EXPECT SW WINDS TO DIMINISH TODAY AS THE PRESSURE GRADIENT
WEAKENS...REMAINING LESS THAN 25 KTS THROUGH THE REST OF THE
FORECAST PERIOD.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...TITUS
AVIATION...JLB
MARINE...TITUS
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
408 PM CST SUN DEC 6 2015
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 400 PM CST SUN DEC 6 2015
THE MAIN CONCERN IN THE SHORT TERM IS THE THREAT OF WIDESPREAD DENSE
FOG ACROSS MUCH OF THE FA TONIGHT. AT MID AFTERNOON...A SURFACE HIGH
WAS LOCATED NEAR KSTC. A FEW POCKETS OF DENSE FOG REMAINED UNDER
THE RIDGE AXIS AROUND KLJF...KOVL...KULM. CLEARING EXISTS JUST
WEST OF THESE SITES. THE CONCERN IS THAT THE POCKETS OF DENSE FOG
WILL CONGEAL AND BEGIN TO SPREAD NW THIS EVENING AS LIGHT SE WINDS
DEVELOP ON THE BACKSIDE OF THE HIGH. THE WORST CASE SCENARIO
CONTINUES TO BE FROM THE HRRR WITH WIDESPREAD DENSE FOG SPREADING
IN ALL DIRECTIONS THIS EVENING. THIS HAS BEEN A TREND SEEN SINCE
EARLY THIS MORNING. THE 18Z HOPWRF HAS A SIMILAR SOLUTION EXCEPT
IT DIMINISHES THE FOG IN THE WESTERN CWA LATE TONIGHT. THE 12Z ARW
KEEPS THE DENSE FOG MORE CONFINED TO WHERE IT IS THROUGH THE
EVENING AND THEN BEGINS TO DIMINISH IT DURING THE OVERNIGHT HOURS
AS THE SURFACE WIND FIELD BEGINS TO INCREASE FROM THE SE. MODELED
THE FORECAST MORE TOWARDS THE ARW DUE TO THE INCREASE IN WINDS TO
THE WEST ALONG WITH THE FACT THAT EASTERN MN AND WESTERN WI ARE
ALREADY COVERED IN MVFR/IFR CEILINGS WITH LITTLE RADIATIONAL
COMPONENT SEEN AS WELL AS THE ADVECTIVE COMPONENT HAVING COME TO
AN END. THEREFORE...MENTIONED DENSE FOG FOR THE AFOREMENTIONED
AREA OF CENTRAL/SOUTH CENTRAL MN THROUGH THE EVENING WITH
VISIBILITIES PICKING UP OVERNIGHT.
OTHERWISE...DRY WEATHER THROUGH THE SHORT TERM PERIOD. LOWS TONIGHT
ARE FORECAST TO BE IN THE MIDDLE TO UPPER 20S. THE COLDEST READINGS
ARE FROM MILLE LACS ON EASTWARD WHERE SOME CLEARING MAY REACH IN
FROM THE NORTH LATE TONIGHT. THERE IS PLENTY OF POTENTIAL FOR WARM
HIGHS ON MONDAY. HOWEVER...MUCH DEPENDS ON THE CLOUD COVER AND THE
HEIGHT OF THE MIXING. KEEPING THE MIXING TO 950 MB YIELDS HIGHS IN
THE LOWER TO MIDDLE 40S. AN EXCEPTION IS NEAR KCNB WHERE DOWNSLOPE
WINDS MAY YIELD HIGHS AGAIN IN THE LOWER 50S. RAISING THE MIXING
HEIGHT TO 925 MB INCREASES HIGH TEMPERATURES SOME 5 TO 8 DEGREES CWA
WIDE. OPTED TO STAY WITH THE LOWER MIXING HEIGHT DUE TO THE CLOUD
COVER UNCERTAINTY ALONG WITH THE SNOW COVER OVER THE WESTERN THIRD
OF THE FA.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 400 PM CST SUN DEC 6 2015
STEADY MILD TEMPERATURES WITH A FEW CHANCES FOR LIGHT/QUICK SHOTS
OF PRECIP ARE THE STORY FOR THE UPCOMING WEEK. AT THIS POINT...THE
DOMINATE PRECIP TYPE IS RAIN.
I COUNT 6-8 SHORTWAVES QUICKLY RIPPLING ACROSS THE NORTHERN CONUS
OVER THE NEXT WEEK. MOST OF THESE WILL HAVE NO MAJOR IMPACTS ON
OUR SENSIBLE WEATHER. THE TWO MORE AMPLIFIED WAVES /ON TUES AND
THURS/ WILL LIKELY BRING LIGHT PRECIP TO OR NEAR THE AREA. THE
FIRST SHORTWAVE MOVES THROUGH ON TUESDAY AND WE HAVE INCREASED
POPS TO FROM 0-10% TO 20-40% DURING THE AFTERNOON AND EVENING. THE
LIMITING FACTOR WITH THIS SYSTEM IS THE ABUNDANCE OF MOISTURE AND
A FAIRLY DRY LOWER ATMOSPHERE BELOW 8000-10000FT. THIS SUGGESTS A
LIGHT QPF EVENT WITH SOME CONCERN IN THE OVERALL PRECIP COVERAGE.
THE FORECAST SOUNDINGS DEPICT A RAIN OR RAIN/SLEET MIX EVEN IF WE
MAXIMIZE OUR WET BULB COOLING...IT SIMPLY LOOKS TOO WARM FOR SNOW
AS THE DOMINANT PRECIP TYPE ON TUESDAY. THE SHORTWAVE SWINGS
THROUGH QUICKLY AND THE PRECIP SHOULD SHUT OFF QUICKLY TUESDAY
NIGHT. LIKE MOST COLD FRONTS THE PAST 3 MONTHS...THE COLD
ADVECTION IS WEAK AND THERE WONT BE MUCH OF A TEMPERATURE
REFLECTION.
WEDNESDAY LOOKS QUIET AND MILD AT THIS POINT...BEFORE ANOTHER
SYSTEM MOVES OUT OF THE GULF OF ALASKA...ACROSS THE PACIFIC
NORTHWEST AND INTO THE FORECAST AREA ON THURSDAY. THIS SYSTEM IS
STRONGER THAN THE TUESDAY SYSTEM AND HAS A BROAD SURFACE LOW IN
THE BALLPARK OF 990MB WHEN IT TRANSVERSES CENTRAL/NORTHERN MN. THE
FORECAST AREA REMAINS ON THE WARM SIDE OF THIS SYSTEM AND SOUTH OF
THE HEAVIER PRECIP AXIS AT THIS POINT.
THE STRONG UPPER JET ACROSS THE PACIFIC BREAKS DOWN LATE THIS WEEK
AND THE CONUS ENDS UP WITH A PRONOUNCED LONGWAVE TROUGH OVER THE
WEST COAST THAT HEADS EAST NEXT WEEKEND. AT THIS POINT...A BAND
OF HEAVY PRECIP WILL LIKELY ACCOMPANY THIS TROUGH...BUT THE MODEL
CONSENSUS IS FORECASTING THE PRECIP WELL SOUTH AND EAST OF THE
FORECAST AREA. THE NUMERICAL GUIDANCE HAS BEEN A LITTLE
INCONSISTENT THE PAST COUPLE DAYS - UNDERSTANDABLE GIVEN HOW FAR
OUT WE ARE. THESE TROUGHS THAT DIG INTO THE SOUTHWEST CONUS AND
THEN LIFT OUT ALWAYS SEEM TO TAKE LONGER THAN WHAT THE MODELS
PREDICT. SO...BRINGING IN PRECIP FRIDAY NIGHT MIGHT BE A LITTLE
AGGRESSIVE AT THIS POINT. STILL A LOT OF UNCERTAINTY IN DAYS 6-8.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1140 AM CST SUN DEC 6 2015
MVFR/IFR CEILINGS COVER ALL BUT KAXN LATE THIS MORNING. VLIFR
VSBYS STILL LINGER FROM WEST OF KSTC THROUGH KRWF...WHICH IS RIGHT
AHEAD THE LOW LEVEL RIDGE AXIS. CONFIDENCE FOR THE FORECAST AHEAD
IS LOW WITH THE MAIN CONCERN BEING THE POSSIBILITY THAT DENSE FOG
DEVELOPS CWA WIDE THIS EVENING. THE CURRENT THINKING IS THAT THE
CEILINGS ACROSS EASTERN MN AND WESTERN WI ARE NOT GOING ANYWHERE
SOON DUE TO THE RIDGE AXIS WORKING INTO THESE AREAS LATE THIS
AFTERNOON AND EVENING. THEREFORE...KEPT CONDITIONS LOW INTO MONDAY
MORNING WITH SOME FOG REDEVELOPING THIS EVENING AS WINDS GO LIGHT
UNDER THE RIDGE. TO THE WEST...LIGHT SOUTHWEST FLOW WILL DEVELOP
LATE TODAY FROM KRWF NORTHWARD KAXN AS WELL AS CLOSE TO KSTC. THIS
MAY BE ENOUGH TO PUSH OUT THE LOW CEILINGS AND VSBYS IN THESE
AREAS DURING THE LATE AFTERNOON AND EARLY THE EVENING.
HOWEVER...WITH THE CLEARING WILL COME THE THREAT OF MORE FOG AND
POTENTIAL LOW CEILINGS DEVELOPING PER THE HRRR. HENCE...ALLOWED
FOR SOME IMPROVEMENT THIS AFTERNOON BUT THEN HELD ON TO LOW MVFR
CEILINGS AND VSBYS THROUGH THE NIGHT WITH BOTH PARAMETERS PERHAPS
NOT LOW ENOUGH.
KMSP...CEILINGS AND VSBYS CONTINUE TO DRIFT LOWER LATE THIS
MORNING. BELIEVE SOME STABILIZATION WILL OCCUR LATE IN THE DAY
WITH CEILINGS NEAR 010 AND 4-6SM VSBYS THROUGH THE NIGHT. THE
SATELLITE AIRPORTS AROUND KMSP MAY EXPERIENCE LOWER CONDITIONS.
IMPROVEMENT BEGINS MONDAY MORNING AS AS SOUTHERLY INCREASES ACROSS
THE REGION...FLUSHING OUT THE LOW CEILINGS/VSBYS.
/OUTLOOK FOR KMSP/
MON NGT...VFR. WINDS S 5 KTS.
TUE...MVFR POSSIBLE WITH -RA. WINDS SSW 5-10 KTS.
WED...VFR. WINDS SW 10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
&&
$$
SHORT TERM...RAH
LONG TERM...CLF
AVIATION...RAH
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
257 PM CST SUN DEC 6 2015
.SHORT TERM: (Tonight and Monday)
Issued at 245 PM CST Sun Dec 6 2015
Potent short wave trof moving through the Mid MS Valley has more
bark than bite and has only managed some small bands of light rain
as the forcing moved into the CWA. This trof and the associated
forcing will exit east into the OH Valley by mid evening, thus
will be mentioning a low chance of rain early this evening to the
east of the MS River. Complications arise in the wake of this
system and the potential for low clouds and fog. System related
clouds aoa 5kft currently blanketing the CWA will shift to the
east, while low stratus over IA will advect into western portions
of the CWA this evening. This low stratus will then slowly advect
into eastern MO later tonight. There are strong indications with
many of the shorter range models, especially the HRRR and SREF,
that dense fog will develop in its wake in an arcing N/S band from
western MO into central MO where sfc winds will become light in
association weak surface ridging. At this time I have mentioned
areas of dense fog late tonight into Monday morning. If the HRRR
is correct then an advisory may ultimately be warranted.
Clouds and fog should clear out west to east on Monday as the
surface ridge moves east and south to westerly flow gets underway
in the lower trop. This should allow for temps to rebound to above
average levels by afternoon.
Glass
.LONG TERM: (Monday through Next Sunday)
Issued at 245 PM CST Sun Dec 6 2015
A progressive flow regime will be in place this upcoming week and
this will lead to very mild temperatures running some 10 to 20
degrees above average. A couple of noteable but quick-moving shortwaves
and associated surface systems will impact the area within the
progressive flow with any cooling quite neglible.The first will
be Tuesday night and have some slight chance pops with it. Another
quick-moving shortwave trof moves across the area Thurs aft/night,
but the impact is primarily to our north. By the end of the week
there is a large scale pattern change with overall amplification
and development of a deep trof in the western U.S.. This trof
progresses into the central U.S. by next weekend leading to
increasing POPS and a greater threat of widespread rainfall.
Glass
&&
.AVIATION: (For the 18z TAFs through 18z Monday Afternoon)
Issued at 1105 AM CST Sun Dec 6 2015
Upper level disturbance continues to move east across the area
this afternoon with some patches of light rain showers expected.
Ceilings are VFR and this is expected to continue until later this
evening and overnight when lower ceilings (stratus) across the
western half of Iowa move south-southeast into the area and align
themselves by 12Z along the Mississippi River. To the west of this
stratus, fog (likely dense) will develop. KCOU would be affected
by this fog and have tempo for 1/2SM late tonight into Monday
morning. Other sites will see the MVFR to IFR stratus deck with
only MVFR visibilities.
Clearing should take place on Monday during the late morning and
early afternoon. Light west wind will become northwest.
Specifics for KSTL:
Mid deck of cloud cover continues to build east and showers across
north central Missouri will move southeast into the terminal by
around 21Z. Rain should end quickly this evening with MVFR and IFR
ceilings arriving late. Light west wind will become northwest.
CVKING
&&
.PRELIMINARY POINT TEMPS/POPS:
Saint Louis 51 38 51 38 / 60 10 0 0
Quincy 47 35 49 36 / 70 5 0 0
Columbia 49 34 53 37 / 50 5 0 0
Jefferson City 50 34 54 36 / 30 5 0 0
Salem 51 38 49 37 / 30 30 5 0
Farmington 53 37 51 35 / 20 10 0 0
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
259 PM CST SUN DEC 6 2015
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 300 PM CST SUN DEC 6 2015
THE MAIN CHALLENGE WILL BE TEMPS AND QPF CHANCES TUE INTO TUE
NIGHT. MODELS ARE IN FAIRLY GOOD AGREEMENT...WITH SOME TIMING AND
PLACEMENT ISSUES WITH QPF TUE/TUE NIGHT. WE PREFER THE GFS THAT
HAS A DECENT HANDLE ON CURRENT SET UP.
FOR TONIGHT...SOUTHERLY WINDS SHOULD REMAIN NEAR 10KT FOR ALL BUT
THE FAR EAST. THE HRRR INDICATES SOME FOG ONCE AGAIN IN THE FAR
EAST SO WILL ADD. TEMPS WILL CONTINUE WELL ABOVE NORMAL.
ON MONDAY...ANOTHER VERY MILD DAY WITH WESTERLY FLOW ONCE AGAIN.
TEMPS SHOULD BE SIMILAR TO TODAY AND MAY EVEN BE A BIT WARMER WITH
MORE WESTERLY WINDS NEAR THE SFC.
FOR MONDAY NIGHT...CLOUDS WILL INCREASE IN THE WEST LATE AND WINDS
SHOULD REMAIN MIXED ENOUGH TO KEEP TEMPS NEAR 30.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 300 PM CST SUN DEC 6 2015
FOR TUE...A SHORTWAVE MOVES THROUGH WITH SOME RAIN...FREEZING RAIN
EARLY TRANSITIONING TO RAIN FAIRLY QUICKLY. THE GFS HAS SOME QPF
SOUTH WITH THE NAM FURTHER NORTH...WITH THE ECMWF MORE
BROADBRUSHED QPF.
ON TUE NIGHT...ANY PRECIP WILL MOVE INTO THE EAST. IT SHOULD BE
MAINLY RAIN THAT COULD MIX WITH A FEW FLAKES BEFORE ENDING.
ON WED...MORE VERY WARM CHINOOK MODIFIED AIR MOVES IN. TEMPS
SHOULD BE INTO THE 40S PERHAPS EVEN WARMER FOR AREAS THAT HAVE NO
SNOW.
FOR WEDNESDAY NIGHT THROUGH SUNDAY...MODELS DEPICT A MUDDY ZONAL
FLOW PATTERN THROUGH THE MIDWEEK PERIOD WITH A TRANSITION TO A
DEEP CENTRAL CONUS TROF FOR THE WEEKEND. THUS WILL EXPECT
SEASONABLY MILD CONDITIONS AND PERIODS OF LIGHT RAIN CHANGING TO
SNOW LATE ON THURSDAY... WITH A TURN TO SOMEWHAT COOLER CONDITIONS
AND A GREATER CHANCE FOR WIDEPSREAD LIGHT SNOW FROM LATE FRIDAY
INTO SUNDAY. SNOWFALL AMOUNTS ARE STILL EXPECTED TO REMAIN SCANT
AT LEAST THROUGH SATURDAY... SO NET IMPACTS OF THE EXPECTED LIGHT
SNOW ON OVERALL TEMPERATURE PATTERNS SHOULD BE SLIGHT. THUS WILL
CONTINUE TO BUMP TEMPERATURES AROUND 10 DEGREES ABOVE LONG TERM
NORMALS YET ON SATURDAY /EXPECTED HIGHS NEAR THE FREEZING POINT/
AND AROUND 5 DEGREES ABOVE NORMAL ON SUNDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1215 PM CST SUN DEC 6 2015
WITH SHALLOW FOG PUSHED OF THE EAST EDGE OF THE FA... EXPECT FAIR
SKIES AND LIGHT SOUTHERLY FLOW THROUGHOUT THE AFTERNOON. SURFACE
TROF SHOULD DEVELOP INTO THE RED RIVER VALLEY BY 12Z MONDAY
MORNING WITHBKN MID TO UPPER LEVEL CLOUDS OVERSPREADING THE FA
FROM 06Z TO 15Z.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
SHORT TERM...DK
LONG TERM...GUST/DK
AVIATION...GUST
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
407 PM CST SUN DEC 6 2015
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 407 PM CST SUN DEC 6 2015
LAST REMNANTS OF STRATUS AND FOG CONTINUE TO HUG OUR EXTREME
EASTERN BORDER OF THE FORECAST AREA. THE WIND BOTH AT THE SURFACE
AND ALOFT IS VERY LIGHT UNDER A RIDGE OF HIGH PRESSURE...SO THUS THE
STRATUS IS HAVING DIFFICULTY EXITING. BOTH THE NAM12 AND RAP13 SHOW
AN EXITING OF THE STRATUS DEEPER INTO IOWA LATE THIS AFTERNOON AND
EVENING. THE PROBLEM IS HOWEVER IS THE FLOW BOTH AT THE SURFACE AND
IN THE BOUNDARY LAYER WILL BECOME SOUTHERLY THIS EVENING IN OUR
EXTREME EAST. THEREFORE ONE WONDERS IF THE CLOUD COVER WILL MOVE
RIGHT BACK INTO OUR FAR EASTERN ZONES AS THE EVENING PROGRESSES
SINCE IT IS SO SLOW TO LEAVE THE AREA NOW. CURRENT THOUGHTS ARE IS
THAT THIS COULD BE A PROBLEM...SO AFTER SOME TEMPORARY CLEARING
EARLY THIS EVENING... HEDGED TOWARD A PARTLY CLOUDY SKY IN THE GRIDS
A BIT LATER AND CERTAINLY INCLUDED A MENTION OF FOG IN OUR EASTERN
ZONES FOR A BULK OF THE NIGHT SINCE IT IS SO POORLY MIXED IN THAT
AREA RIGHT NOW.
ELSEWHERE...THE SOUTHERLY GRADIENT PICKS UP WHICH SHOULD KEEP MOST
OF THE FOG AT BAY...ALTHOUGH WOULD NOT RULE OUT A LOT OF MVFR TYPE
FOG MENTIONED IN THE AVIATION DISCUSSION BELOW. LATE TONIGHT AS THE
WINDS AND GRADIENT SLACKEN...THE FOG FROM I 29 AND WESTWARD COULD
BECOME A BIT MORE OF A THREAT ESPECIALLY IN THE JAMES RIVER VALLEY
WHERE THE WINDS SHOULD GO FAIRLY DEAD. LOWS TONIGHT WILL ONCE AGAIN
BE MILD FOR THIS TIME OF YEAR AND TERRAIN DRIVEN.
HIGHS ON MONDAY SHOULD BE VERY MILD AS SNOW COVER WANES AND A CROSS
GRADIENT SOUTHWEST SURFACE FLOW SETS UP IN THE AFTERNOON. 925MB
TEMPERATURES ARE SIMILAR TO TODAYS TEMPERATURES...THEREFORE PLACED
HIGHS SIMILAR TO TODAYS HIGHS. MANY OF THE GUIDANCE VALUES WERE WAY
TOO COOL...SO ONCE AGAIN HAD TO BLEND IN WARMER ECMWF AND GEM GLOBAL
VALUES TO ACCOUNT FOR THE WELL ABOVE NORMAL AIR MASS.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 407 PM CST SUN DEC 6 2015
SYSTEM TUESDAY HAS RETURNED TO A MORE COHERENT DYNAMIC LOOK...WITH
BEST QG FORCING SLIPPING JUST THROUGH THE NORTHEAST HALF OF THE CWA
FROM LATE MORNING TO EARLY AFTERNOON. MOISTURE AGAIN THE MAIN
DETRACTOR FROM CARRYING TOO HIGH OF POPS...WITH DRY LOWER LEVELS.
EXPECT THERE WILL BE AREAS OF LIGHT PRECIP...BUT NOT MORE WIDESPREAD.
TEMPS WILL GO INTO A HOLDING PATTERN FOR MUCH OF THE AREA WITH THE
INCREASED CLOUDINESS...BUT WILL GET SOME BETTER MIXING AND SOME
CLEARING BEHIND THE WEAK FRONT THROUGH THE WESTERN CWA. EXPECT THAT
DIMINISHED SNOWCOVER WILL ONLY HAVE NOTICEABLE IMPACT IN PARTS OF SW
MN AND NW IA BY THIS TIME.
WEAK UPPER LEVEL RIDGING FOR WEDNESDAY AND DEVELOPMENT OF STRONGER
SOUTH TO SOUTHWEST FLOW WILL BRING WARMER AIRMASS INTO THE AREA.
WILL AGAIN HAVE SPECTER OF HIGHER CLOUDS AROUND THROUGH THE DAY TO
IMPACT INSOLATION...BUT STILL ENOUGH OF A WARM PUSH TO EXPECT SOME
NEAR 60 DEGREE READINGS TOWARD SOUTH CENTRAL SD WHERE SNOW WILL
ALMOST CERTAINLY BE GONE...IF NOT EVEN WARMER.
ANOTHER SPEEDY PACIFIC WAVE WILL AMPLIFY HEADING TO THE EAST AND
SOUTHEAST INTO THE NORTHERN PLAINS WEDNESDAY NIGHT AND THURSDAY.
ASSOCIATED SURFACE FRONT WILL PUSH THROUGH LATER WED NIGHT OR EARLY
THURSDAY...LEAVING DAYTIME WITH ENHANCED MIXING POTENTIAL. WARM
ENOUGH ALOFT FOR ONLY LIQUID...AND SURFACE TEMPS SHOULD REMAIN MILD
AT OR ABOVE FREEZING EARLY ON WITH MIXING. THROUGH THE DAY...SHOULD
BE ABLE TO SEE VERY MILD UPPER 40S TO MID 50S...BEFORE DECOUPLING
LATE DAY AND ALLOWING A DECENT EVENING TEMP FALL.
MODEL INCONSISTENCY AND DISAGREEMENT PRETTY MUCH PUTS THE END OF THE
FORECAST IN DEFENSIVE MODE. DOES NOT APPEAR TO BE THE THREAT FOR
MUCH OF A SIGNIFICANT SYSTEM THROUGH THE AREA AS THERE IS AT LEAST A
WEAK CONSENSUS OF NORTHERN/SOUTHERN SPLIT WITH WEAKER NORTHERN LEAD
WAVE ACTING TO PUSH BOUNDARY SOUTHEAST ON FRIDAY AND SATURDAY...WITH
ENERGY DUMPED INTO SOUTHWEST SET TO ARRIVE TOWARD THE VERY END OF
THE PERIOD AROUND SUNDAY...AND MORE PROBABLE TO SWING OUT ALONG THE
BOUNDARY WELL TO THE SOUTHEAST OF THE AREA. FOR THE TIME...WILL
CONTINUE SOME FAIRLY LOW POPS FRIDAY INTO SATURDAY...WITH EVER SO
SLIGHTLY HIGHER AROUND FRIDAY NIGHT WHEN A GREATER PROBABILITY OF
JET/FRONT INTERACTION ALONG WITH SOME TIME TO SATURATE THE DRIER LOW
LAYER. DID NOT DWELL GREATLY ON SPECIFIC PRECIP TYPE DUE TO
CARRYING SUCH LOW POPS...BUT IN GENERAL WILL BE WARM ENOUGH ALOFT
FOR ALL LIQUID FOR MOST OF FRIDAY...WITH TEMPS MARGINAL FOR SOME
MORNING FREEZING PRECIP IN THE SOUTH CENTRAL...BEFORE COLDER AIR
FILTERING SOUTHWARD WORKS A TRANSITION OF THREAT TOWARD SNOW FROM
NORTHWEST TO SOUTHEAST WITH SLOW COLLAPSE OF DEEPER BAROCLINICITY.
AGAIN...DELAY IN THE ARRIVAL OF BETTER LOW LEVEL MOISTURE ALONG WITH
THE NORTHWARD PATH OF LEADING SHEARING WAVE LEAVES DYNAMICAL SUPPORT
PRETTY NEBULOUS. THERE IS POTENTIAL THAT THE SYSTEM COULD BECOME
MORE ORGANIZED...SO KEEP AN EYE ON TRENDS THE NEXT FEW DAYS AS
PACIFIC ENERGY IMPACTS THE LARGER SCALE FLOW. STILL MILD ON FRIDAY
WITH 40S TO LOWER 50S...BUT TEMPS BEHIND BOUNDARY WILL DROP BACK
INTO THE 30S FOR THE WEEKEND...WITH LOWS MAINLY 20S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1136 AM CST SUN DEC 6 2015
VFR WILL PREVAIL IN THE NEAR TERM THIS AFTERNOON AND EARLY
EVENING. HOWEVER ESPECIALLY AT SIOUX CITY...AM CONCERNED ABOUT FOG
DEVELOPING AS THEY ARE CURRENTLY CLOSEST TO THE STRATUS WHICH IS
NOT TOO FAR OFF TO THE EAST. BOTH THE NAM AND RAP SHOW THE STRATUS
FIELD SLOWLY EDGING OFF TO THE SOUTHEAST AS THE AFTERNOON AND
EVENING PROGRESS DEEPER INTO IOWA. HOWEVER IT IS QUITE POSSIBLE
THAT AS THE LOW LEVEL WINDS TURN TO THE SOUTH AND SOUTHEAST THIS
EVENING...THAT SOME OF THAT RESIDUAL LOW LEVEL MOISTURE COULD
ADVECT INTO THE KSUX AREA...ESPECIALLY GIVEN A FAVORABLE EAST TO
SOUTHEAST WIND AT KSUX WHICH IS A COOL MOIST WIND. THEREFORE FOR
NOW...PUT IN IFR VISIBILITIES FOR KSUX LATER TONIGHT AND EARLY
MONDAY. AT KHON AND KFSD...THERE COULD BE ENOUGH GRADIENT AND WIND
TO KEEP MOST FOG AT BAY...BUT DID INCLUDE MVFR VISIBILITIES WITH
THE MOIST GROUND.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
SHORT TERM...MJ
LONG TERM...CHAPMAN
AVIATION...MJ
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1141 AM CST SUN DEC 6 2015
.UPDATE...
ISSUED AT 955 AM CST SUN DEC 6 2015
UPDATED TO EXTEND THE DENSE FOG ADVISORY IN NORTHWEST IOWA UNTIL
NOON. AT 9 AM...MANY SITES WERE STILL AT A QUARTER MILE OR LESS IN
VISIBILITY...AND SATELLITE IMAGERY SHOWS THE STRATUS ONLY VERY
SLOWLY ERODING. CURRENT THOUGHTS ARE THAT THE VISIBILITY WILL
IMPROVE BY MIDDAY...BUT THE STRATUS MAY BE TOUGH TO GET RID OF IN
OUR EXTREME SOUTHEAST ZONES. THEREFORE COOLER HIGHS IN THAT LOCATION
ARE STILL WARRANTED.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 346 AM CST SUN DEC 6 2015
LOW CONFIDENCE TODAY IN TERMS OF SKY COVER AND TEMPERATURES.
CURRENTLY...TROUGH MOVING THROUGH THE AREA WITH FAIRLY DENSE AND
WIDESPREAD FOG AHEAD OF THE TROUGH. BEHIND THE TROUGH...PATCHY FOG
PERSISTS AND WITH WEAK WINDS AND STOUT INVERSION REMAINING ACROSS
THE AREA...QUESTIONS REMAIN AS TO HOW QUICK THE FOG WILL BURN
OFF...IF AT ALL. BOTH THE HRRR AND RAP KEEP FOG AROUND FOR THE
BETTER PART OF THE DAY...AND EXPAND IT ACROSS THE REGION TONIGHT.
HAVE SIDED WITH CONS SHORT SOLUTION WHICH HAS THE FOG GRADUALLY
BURNING OFF THROUGH THE LATE MORNING HOURS. HAVE SIDED WITH COOLER
GUIDANCE FOR TODAY WITH LOWER SUN ANGLE...WEAK WINDS AND POTENTIAL
STRATUS/FOG ISSUES...HOWEVER...IF FOG IS ABLE TO CLEAR...DAY SHIFT
WILL LIKELY NEED TO RAISE HIGHS 3-5 DEGREES.
FOG POTENTIAL CONTINUES INTO TONIGHT AS SURFACE RIDGE MOVES ACROSS
THE AREA. EXPECT TEMPERATURES TO RISE AFTER MIDNIGHT AS STOUT
SOUTH/SOUTHWEST FLOW INCREASES AHEAD OF A WEAK TROUGH PASSING
THROUGH THE REGION MONDAY MORNING.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 346 AM CST SUN DEC 6 2015
MONDAY MORNING SHOULD START OUT VERY MILD AS A SOUTHERLY BREEZE
BRINGS TEMPERATURES UP QUICKLY. THE GRADIENT SLACKENS JUST A TOUCH
AND WINDS BECOME MORE WESTERLY. WITH DEEPER MIXING POTENTIAL AND A
CONTINUOUSLY DECREASING SNOW COVER HAVE OPTED TO KEEP HIGHS SIMILAR
TO PREVIOUS FORECAST...MAINLY MID 40S TO AROUND 50.
MONDAY NIGHT INTO TUESDAY WILL SEE THIS WESTERLY INFLUENCE CONTINUE
SO VERY MILD LOWS IN THE 20S TO LOWER 30S AND WENT AHEAD AND RAISED
HIGHS A BIT AS SNOW COVER WILL BE GREATLY DIMINISHED BY TUESDAY.
HAVE HIGHS FROM THE MID 40S IN THE BIG SIOUX RIVER VALLEY TO THE
LOWER 50S ALONG THE MISSOURI RIVER CORRIDOR. COULD EVEN GET CLOSER
TO 50 ALONG AND EAST OF THE BUFFALO RIDGE WITH POTENTIAL FOR
ENHANCED MIXING AND LESS SNOW COVER.
IN THE OUTER PERIODS(WEDNESDAY THROUGH SATURDAY)...FAST WESTERLY
FLOW TRANSITIONS TO DEEPER SOUTHERLY FLOW AS A TROUGH OF LOW
PRESSURE DEEPENS OVER THE ROCKIES AND MOVES ONTO THE PLAINS FRIDAY
NIGHT INTO SATURDAY. A RELATIVELY STRONG UPPER LEVEL WAVE WILL MOVE
THROUGH WEDNESDAY NIGHT INTO THURSDAY BUT THE STRONGER FORCING...AND
THUS BETTER CHANCES FOR PRECIPITATION...LOOK TO REMAIN TO THE NORTH
OF THE AREA. PRECIPITATION CHANCES BEGIN TO INCREASE FRIDAY NIGHT
INTO SATURDAY AS THE TROUGH MOVES ONTO THE PLAINS BUT THE MODELS ALL
OVER THE PLACE ON PLACEMENT SO CONFIDENCE ON JUST WHAT WILL HAPPEN
STILL A LITTLE LOW. WILL SIDE A LITTLE MORE CLOSELY TO THE ECMWF
WITH SOME WEIGHTING FROM THE GFS WHILE MOSTLY IGNORING THE GEM. THE
GEM SEEMS A BIT TOO AGGRESSIVE WITH THE WARM SECTOR FRIDAY INTO
SATURDAY...BUT WILL WATCH TRENDS AS THIS PATTERN NOT IMPOSSIBLE BUT
A LITTLE OUT OF SEASON WITH LITTLE TO NO HUDSON BAY LOW INFLUENCE
AND SUGGESTING MUCH MORE RIDGING WHICH IS PRETTY FAR NORTH FOR THIS
TIME OF YEAR. TEMPERATURES WELL ABOVE NORMAL WEDNESDAY AND
THURSDAY...STILL ABOVE NORMAL BUT NOT BY QUITE SO MUCH FRIDAY THEN
CLOSER TO NORMAL BY THE WEEKEND.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1136 AM CST SUN DEC 6 2015
VFR WILL PREVAIL IN THE NEAR TERM THIS AFTERNOON AND EARLY
EVENING. HOWEVER ESPECIALLY AT SIOUX CITY...AM CONCERNED ABOUT FOG
DEVELOPING AS THEY ARE CURRENTLY CLOSEST TO THE STRATUS WHICH IS
NOT TOO FAR OFF TO THE EAST. BOTH THE NAM AND RAP SHOW THE STRATUS
FIELD SLOWLY EDGING OFF TO THE SOUTHEAST AS THE AFTERNOON AND
EVENING PROGRESS DEEPER INTO IOWA. HOWEVER IT IS QUITE POSSIBLE
THAT AS THE LOW LEVEL WINDS TURN TO THE SOUTH AND SOUTHEAST THIS
EVENING...THAT SOME OF THAT RESIDUAL LOW LEVEL MOISTURE COULD
ADVECT INTO THE KSUX AREA...ESPECIALLY GIVEN A FAVORABLE EAST TO
SOUTHEAST WIND AT KSUX WHICH IS A COOL MOIST WIND. THEREFORE FOR
NOW...PUT IN IFR VISIBILITIES FOR KSUX LATER TONIGHT AND EARLY
MONDAY. AT KHON AND KFSD...THERE COULD BE ENOUGH GRADIENT AND WIND
TO KEEP MOST FOG AT BAY...BUT DID INCLUDE MVFR VISIBILITIES WITH
THE MOIST GROUND.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...DENSE FOG ADVISORY UNTIL NOON CST TODAY FOR IAZ002-003-012>014-
020>022-031-032.
NE...NONE.
&&
$$
UPDATE...MJ
SHORT TERM...
LONG TERM...08
AVIATION...MJ