SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NWS LOS ANGELES/OXNARD CA
910 PM PDT SUN SEP 21 2008
.SHORT TERM (TONIGHT-WED)...LAX ACARS SOUNDINGS THIS EVENING SHOWING
TWO INVERSIONS...ONE AT ABOUT 1800 FT AND ANOTHER AT ABOUT 4800 FT.
DISORGANIZED MARINE LAYER CLOUDS WERE OVER THE SOCAL BIGHT MAINLY S
OF THE CHANNEL ISLANDS AND OFF THE COAST FROM L.A. COUNTY SOUTHWARD.
AN EDDY IS EXPECTED TO DEVELOP OVERNIGHT WHICH SHOULD HELP TO
SOLIDIFY THE MARINE LAYER CLOUD COVER AND PUSH THE CLOUDS INLAND TO
THE VALLEYS AND UP THE COAST TO VTU AND S SBA COUNTY LATER TONIGHT.
LOW CLOUDS WERE SPARSER ALONG AND OFF THE CENTRAL COAST THIS
EVENING. IT LOOKS LIKE LOW CLOUDS SHOULD PERSIST ALONG THE SBA
CENTRAL COAST OVERNIGHT BUT THE EXTENT OF LOW CLOUDS FOR THE SLO
CENTRAL COAST IS QUESTIONABLE. THE WRF IS FORECASTING SOME OFFSHORE
LOW LEVEL FLOW ALONG THE CENTRAL COAST LATE TONIGHT WHICH MAY CAUSE
ANY LOW CLOUDS TO BE PUSHED OFF THE COAST BY SUNRISE...WHICH THE
BOUNDARY LAYER MOISTURE FIELDS ARE SUGGESTING. IT ALSO APPEARS LOW
CLOUDS MAY BE HARD PRESSED TO MOVE INTO THE SALINAS VALLEY LATER
TONIGHT AS WELL. OTHERWISE MOSTLY CLEAR SKIES SHOULD PREVAIL OVER A
GOOD PORTION OF THE FORECAST AREA THROUGH TONIGHT.
A BROAD UPPER TROF OVER CA IS FORECAST TO MOVE E THRU MON...WITH AN
UPPER RIDGE EXPECTED TO BUILD INTO SRN CA FOR TUE THRU WED. A BROAD
WNW FLOW ALOFT CA BE EXPECTED OVER THE DISTRICT THRU MON THEN THE
FLOW WILL TURN MORE WSW FOR TUE AND GENERALLY SOUTHERLY FOR WED. DRY
WEATHER WILL CONTINUE OVER THE DISTRICT THRU WED...WITH GRADUALLY
WARMING TEMPS THRU THE PERIOD. BY WED HI TEMPS SHOULD BE WELL ABOVE
NORMAL IN MANY AREAS AWAY FROM THE IMMEDIATE COAST. THE MARINE LAYER
SHOULD SHRINK SOME AS WELL AND BE AROUND OR JUST BELOW 1000 FT DEEP
BY WED...WITH JUST PATCHY NIGHT AND MORNING LOW CLOUDS AND FOG
EXPECTED FOR THE COASTAL PLAIN BY TUE NIGHT. THE WRF WAS FORECASTING
LITTLE IF ANY LOW CLOUDS FOR THE CENTRAL COAST BY TUE NIGHT AS WELL.
...FROM PREVIOUS DISCUSSION...
.LONG TERM (THU-SUN)...MODELS HAVE BEEN FLIP FLOPPING A BIT FOR THU
AND FRI. A TROUGH SHOULD DIG DOWN FROM ALASKA AND PUSH OUR WARM
RIDGE EASTWARD...BUT WHETHER THAT HAPPENS THU NIGHT LIKE THE 0Z RUNS
SUGGESTED OR FRI NIGHT LIKE THE 12Z RUNS IS LEFT TO BE SEEN. THE 12Z
RUNS ACTUALLY WEAKEN THE ORIGINAL TROUGH...WHILE A RATHER LARGE
TROUGH JUST SOUTH OF ALASKA STEALS SOME OF ITS ENERGY. THIS NEW
SOLUTION RESULTS IN SHIFTING THE HIGH ONLY SLIGHTLY TO THE
EAST...AND KEEPING US FAIRLY WARM FRI THROUGH SUN. NOT ONLY
THAT...BUT THIS PATTERN PUTS THE HIGH INTO A FAVORABLE SOUTHERLY
FLOW REGIME FOR OUR AREA...WHICH COULD PULL UP ANY AVAILABLE
MOISTURE FROM MEXICO. DID NOT BITE ON THIS JUST YET...SINCE THIS
MOISTURE WOULD NOT GET HERE UNTIL FRIDAY...BUT IF THE MODELS
CONTINUE TO SING THE SAME TUNE THROUGH THIS WEEK...IT WILL BE TOUGH
TO IGNORE FOR LONG. EITHER WAY...FRI THROUGH SUN SHOULD BE A BIT
COOLER...BUT UNTIL WERE SEE MORE STABILITY IN THE SOLUTIONS...DID
NOT GET TOO CUTE AND JUST TRENDED TEMPS DOWN A BIT EACH DAY BACK
TOWARD NORMAL.
&&
.AVIATION...22/0406Z...SOME LOW CLOUDS WERE NOTED ON THE CENTRAL
COAST THIS EVENING. LOW CLOUDS SHOULD EVENTUALLY DEVELOP OVER A
WIDER PORTION OF THE CENTRAL COAST TONIGHT AND MOVE INTO KSMX AND
KSBP BY MIDNIGHT OR SHORTLY AFTER. THE WRF WAS FORECASTING LIGHT
OFFSHORE FLOW FOR THIS AREA LATER TONIGHT SO IT IS POSSIBLE ANY LOW
CLOUDS THAT DO MOVE INTO THE AIRFIELDS MAY CLEAR OUT AS EARLY AS 7
AM OR 8 AM. LOW CLOUDS ALSO EXPECTED TO DEVELOP AROUND KPRB LATE
TONIGHT AND EARLY MON.
S OF POINT CONCEPTION...TIMING OF LOW CLOUDS RATHER DIFFICULT...BUT
IT LOOKS LIKE THE LOW CLOUDS SHOULD MOVE INTO KLGB AND KLAX BY 07Z
OR 08Z AS AN EDDY DEVELOPS...THEN SPREAD UP THE COAST AND EVENTUALLY
AFFECT KOXR AND KSBA WITH IFR TO LOW MVFR CIGS. LOW CLOUDS SHOULD
ALSO MOVE INTO KBUR AND KVNY BY 11Z TO 12Z WITH MVFR CIGS. ALL THE
LOW CLOUDS ARE EXPECTED TO CLEAR TO VFR BY MIDDAY MON AND CONTINUE
VFR THRU MON AFTERNOON
FOR KLAX...MODERATE TO HI CONFIDENCE LOW CLOUDS AND MVFR CIGS WILL
MOVE IN BY 07Z THEN PERSIST THRU 19Z OR 20Z BEFORE CLEARING TO VFR
FOR THE REMAINDER OF THE DAY. NO WIND ISSUES ARE EXPECTED THRU MON.
FOR KBUR...MODERATE CONFIDENCE LOW CLOUDS AND MVFR CIGS WILL DEVELOP
BY 12Z MON THEN CLEAR TO VFR BY 18Z. NO WIND ISSUES ARE EXPECTED
THRU MON.
&&
.LOX WATCHES/WARNINGS/ADVISORIES...
SMALL CRAFT ADVISORY (SEE LAXMWWLOX).
&&
$$
PUBLIC...SIRARD/KITTELL
AVIATION...SIRARD
WWW.WEATHER.GOV/LOSANGELES
SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION...UPDATED
NWS LOS ANGELES/OXNARD CA
1045 PM PDT FRI SEP 19 2008
.SHORT TERM (TODAY-MON)...
TEMPERATURES COOLED DOWN RATHER SIGNIFICANTLY ACROSS PORTIONS OF THE
SLO INTERIOR VALLEYS WHERE PASO ROBLES ONLY REACHED 76 DEGREES
TODAY. MOST OTHER INTERIOR LOCATIONS WERE DOWN BETWEEN 3-5 DEGREES
AS BOUNDARY LAYER TEMPS COOLED A BIT AND THICKNESS LVLS DROPPED IN
THE WAKE OF A WEAK FRONTAL BOUNDARY THAT MOVED INLAND OVERNIGHT.
MOST LA/VTU SBA COUNTY VALLEYS REMAINED IN THE 80S. WHILE LOW CLOUDS
WERE ABSENT OVERNIGHT AND THIS MORNING...DOWNTOWN WAS ABLE WARM UP
AS HIGH AS PALMDALE TO 86 DEGREES.
CURRENTLY...SKIES ARE MOSTLY CLEAR SOUTH OF POINT CONCEPTION...WHILE
A BAND OF CLOUDS ASSOCIATED WITH A WEAK TROF WITH CIGS OF NEAR 5000
FT IS BEGINNING TO SURGE INTO THE CENTRAL COAST THIS EVENING. HARD
TO TELL THE EXTENT OF CLOUD COVERAGE OVERNIGHT...BUT MODELS SUGGEST
THAT CLOUDS SHOULD MOVE INTO THE SALINAS RIVER VALLEY OVERNIGHT. NOT
ANTICIPATING ANY FOG DUE TO HIGH CLOUD BASES. LATEST AMDAR SOUNDING
NEAR KLAX INDICATED MARINE LAYER NEAR 800 FT...BUT WITH APPROACHING
WEAK TROF...MARINE LAYER SHOULD DEEPEN WHILE INVERSION WEAKENS
OVERNIGHT. NAM-WRF IS ADVERTISING EDDY CIRCULATION TO HELP SPIN UP
SOME STRATUS ACROSS LA/VTU COUNTY COASTAL AREAS OVERNIGHT. FEEL THAT
THERE WILL BE SOME PATCHY LOW CLOUDS ACROSS LA COUNTY AFTER
MIDNIGHT...AND POSSIBLY VTU COUNTIES. WITH INVERSION WEAKENING...LOW
CLOUDS COULD POP UP RANDOMLY ACROSS PORTIONS OF LA/VTU COUNTY
COASTAL AREAS...BUT SHOULD REMAIN PATCHY IN NATURE. KEPT SKIES CLEAR
FOR SBA SOUTH COAST OVERNIGHT...BUT WITH A FEW BANDS OF CLOUDS NEAR
POINT CONCEPTION...A MINI EDDY COULD DEVELOP BETWEEN SBA AND THE
CHANNEL ISLANDS LATER TONIGHT. HOWEVER...THERE IS A DECENT NORTHERLY
GRADIENT BETWEEN KSBA-KSMX WHICH SHOULD KEEP THE SANTA BARBARA SOUTH
COAST CLEAR.
SATURDAY LOOKS TO BE A FEW DEGREES COOLER...ALTHOUGH 950 MB TEMPS DO
NOT CHANGE MUCH...BUT ONSHORE FLOW INCREASES ACROSS THE REGION.
EXPECT MOST VALLEY LOCATIONS TO BE IN THE MID 80S. WHILE THE COASTAL
AREAS REMAIN FROM THE UPPER 60S AND 70S TO AROUND 80 INLAND AREAS.
A MORE IMPRESSIVE EDDY DEVELOPS ACROSS THE SO CAL BIGHT SAT NIGHT
AND SHOULD REACH THE COASTAL VALLEYS KEEPING TEMPS COOLER THAN AVG
ON SUNDAY. THERE CONTINUES TO BE A DECENT NORTHERLY GRADIENT
AFFECTING THE SANTA BARBARA COUNTY MTNS AND SBA SOUTH COAST WHICH
SHOULD BRING ADDITIONAL LOCAL GUSTY NORTHWEST TO NORTH WINDS ACROSS
THE USUAL WINDY PASSES AND CANYONS NEAR GAVIOTA TO MONTECITO. MODELS
ALSO PICK UP SOME LOCAL NORTHERLY WINDS 15 TO 30 MPH ACROSS THE I-5
CORRIDOR LATE SAT NIGHT INTO EARLY SUNDAY MORNING WITH A FEW CLOUDS
POSSIBLE PUSHED UP AGAINST THE NRN SLOPES OF THE VTU/WESTERN LA
COUNTY MTNS EARLY SUNDAY MORNING. THERE COULD BE A FEW DEGREES OF
WARMING ACROSS THE INTERIOR PORTIONS OF THE FORECAST AREA AS WEEK
UPPER RIDGE SLOWLY BUILDS IN FROM THE SOUTHWEST. HOWEVER A CATALINA
EDDY SHOULD PERSIST SUNDAY NIGHT INTO MONDAY CONTINUING TO LEAVE THE
COASTAL AREAS RELATIVELY COOL FOR MONDAY.
...FROM PREVIOUS DISCUSSION...
.LONG TERM (TUE-FRI)...WARMING TREND STILL ON TRACK FOR THE MIDDLE
OF NEXT WEEK. GFS HAS BACKED OFF SLIGHTLY ON THE OFFSHORE FLOW FOR
WED AND THU BUT GRADIENTS SHOULD AT LEAST BE NEAR NEUTRAL IF NOT
SLIGHTLY OFFSHORE. STILL THINK THE GFS IS UNDERDOING THE WARMING AT
950 AS WELL THE MOS GUIDANCE HIGHS. GIVEN THE STRENGTH OF THE UPPER
HIGH AND NEAR NEUTRAL OR SLIGHTLY OFFSHORE SURFACE GRADIENTS, HIGHS
SHOULD BE CLOSE TO 100 IN THE VALLEYS AND CLOSE TO 90 ACROSS THE
INLAND COASTAL PLAIN. FOR THIS REASON CURRENT FORECAST CONTINUES TO
BE WARMER THAN MOS GUIDANCE. WARMING TREND SHOULD END FRI AS ANOTHER
TROF APPROACHES THE COAST AND HIGH PRESSURE MOVES EAST.
&&
.AVIATION...20/0545Z.
STRATUS WILL BE PATCHY IN NATURE S OF POINT CONCEPTION...CONFINED
MAINLY TO THE COASTAL PLAIN. N OF PT CONCEPTION...EXPECT WDSPRD IFR
CIGS THROUGH 17Z. THERE WILL BE SOME LL WIND SHEAR NEAR KSBA THROUGH
12Z.
KLAX...THERE IS A 70 PERCENT CHANCE OF LOW CLOUDS AND FOG WITH
IFR OR LOW MVFR CIGS AND MVFR VSBYS BETWEEN 11Z AND 17Z.
KBUR...HIGH CONFIDENCE IN CLEAR SKIES THROUGH SATURDAY.
&&
.LOX WATCHES/WARNINGS/ADVISORIES...
SMALL CRAFT ADVISORY (SEE LAXMWWLOX).
&&
$$
PUBLIC...KAPLAN/WOFFORD
AVIATION...SWEET
WWW.WEATHER.GOV/LOSANGELES
AREA FORECAST DISCUSSION
NWS UPTON NY
929 AM EDT SAT SEP 20 2008
.SYNOPSIS...
LARGE HIGH PRESSURE RIDGE WILL FINALLY GIVE WAY TO A WEAK COLD FRONT
LATE SUNDAY. THIS FRONT WILL SLOWLY MOVE THROUGH SUNDAY NIGHT AND
MONDAY...THEN ANOTHER AREA OF HIGH PRESSURE WILL SETTLE OVER THE
AREA THROUGH MID WEEK. A DEVELOPING COASTAL LOW MAY APPROACH THE
AREA LATE IN THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
MORNING SOUNDING SHOWS VERY STABLE ATMOSPHERE WITH STRONG
SUBSIDENCE ALOFT AS SEEN ON WATER VAPOR IMAGERY AS WELL. LOW LEVEL
MOISTURE BELOW THE INVERSION SEEN ON SOUNDING AND ACARS/TAMDAR
PROFILES PRODUCING STRATUS SOUTH OF LONG ISLAND...BUT SPILLING UP
INTO QUEENS AND NASSAU. DUE TO HEATING...FEEL THAT RUC AND NAM
SOUNDINGS ARE CORRECT IN MIXING THESE CLOUDS OUT TO SCATTERED.
WITH A GOOD DEAL OF SUNSHINE THIS AFTERNOON...TEMPERATURES WILL
WARM A FEW DEGREES HIGHER THAN WHAT WAS OBSERVED YESTERDAY DUE TO
WEAKER EASTERLY LOW LEVEL FLOW...AND THUS DEEPER MIXED LAYER.
MOS/LAV NUMBERS CONTINUE TO LOOK GOOD.
SEE TIDE SECTION BELOW FOR THE MINOR COASTAL FLOOD CONCERN.
MODERATE RIPS AT THE OCEAN BEACHES. SEE MARINE SECTION.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/...
AS THE RIDGE SETTLES OVER THE AREA AND WEAK FRONT APPROACHES FROM
THE NORTHWEST...LOW LEVEL EASTERLY FLOW WILL END. AS SUCH...SKIES
WILL REMAIN CLEAR TONIGHT.
UPPER TROUGH THAT REMAINS WELL TO THE NORTH WILL SLOWLY PROGRESS
EAST ACROSS SOUTHEAST CANADA. AT THE SURFACE...WEAK FRONT BETWEEN
RIDGE TO THE SOUTH AND NEXT AREA OF HIGH PRESSURE UP IN CENTRAL
CANADA WILL APPROACH THE REGION. THIS WILL OCCUR LATER SUNDAY AND
SUNDAY NIGHT. AN INCREASE IN LOW LEVEL MOISTURE POOLING AHEAD OF
FRONT...AND WEAK FORCING COULD TRIGGER AN ISOLATED SHOWER OR
SPRINKLE. BEST TIME FOR ANY PRECIP LOOKS TO BE SUNDAY NIGHT INTO
EARLY MONDAY. THEN RIDGE PREDOMINATES LATER MONDAY...AND ATMOSPHERE
DRIES OUT QUICKLY.
TEMPS...SEASONABLE NIGHT TONIGHT...THEN WARMER AIR SWEEPS IN AHEAD
OF SFC FRONT SUNDAY. 950 HPA TEMPS WARM FROM 12-13C SATURDAY
(EASTERLY LOW LEVEL FLOW) TO 18-19C SUNDAY.
EXPECTED CLOUD COVER SUNDAY NIGHT WILL KEEP READINGS A TAD HIGHER
THAN PREVIOUS NIGHTS...BUT MONDAY SHOULD BE QUITE COOL AS CLOUDS
LINGER AND NORTHEAST FLOW SETS UP ONCE AGAIN.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
BUILDING HIGH PRESSURE WILL RESULT IN ANOTHER STRETCH OF DRY WEATHER
THROUGH AT LEAST THU. PERSISTENT NE-E CAN BE EXPECTED THROUGH THE
PERIOD AS THE HIGH REMAINS ANCHORED NORTH OF THE AREA.
THERE CONTINUES TO MODEL UNCERTAINTY ABOUT HOW CLOSE A LOW OFF THE
SE COAST WILL APPROACH IN THE THURSDAY NIGHT THROUGH SATURDAY TIME
FRAME. LATEST GUIDANCE SUGGESTS THAT RIDGING WILL REMAIN FIRMLY IN
PLACE DURING THE PERIOD...RESULTING IN A MORE EASTERLY TRACK OF THE
SURFACE LOW. GIVEN UNCERTAINTY REGARDING THIS SURFACE LOW...HAVE
KEPT POPS LOW FOR THURSDAY NIGHT THROUGH FRIDAY NIGHT.
&&
.AVIATION /13Z SATURDAY THROUGH WEDNESDAY/...
OVERALL...VFR WITH HIGH PRESSURE.
PAN-CAKE STRATO-CU DUE TO SURFACE HEATING WILL BE BROKEN AT TIMES
THIS AM ON LONG ISLAND. BASES OF 025 EARLY RISE BY THIS AFTERNOON.
WINDS ARE TRICKY AS THE REGION IS IN A TUG OF WAR BETWEEN A RIDGE
OF HIGH PRESSURE THAT RUNS ALONG AND JUST INSIDE OF THE I-95
CORRIDOR...AND OFFSHORE LOW OVER THE ATLANTIC. WILL KEEP A GENERAL
NE-E FLOW ACROSS THE AREA....AS I EXPECT THE RIDGE AXIS TO REMAIN
TO OUR NORTH...WITH JUST ENOUGH INFLUENCE FROM THE OFFSHORE LOW TO
KEEP THE FLOW FROM TURNING MORE ONSHORE. SPEEDS STAY LESS THAN 10
KT.
NYC METRO WINDS...LGA EXPECTED TO HOLD ITS TYPICAL NE
DIRECTION THROUGH THE AFTERNOON WHILE JFK FLIPS OVER TO SOUTHERLY
SEA BREEZE. KEWR MAY BE MORE VARIABLE...BUT FORECASTING A MORE
SOUTHERLY FLOW BASED ON LATEST DATA AND COLLABORATION WITH ZNY.
LOW CONFIDENCE ON TIMING OF DIRECTION/RUNWAY CONFIG CHANGE AT
KEWR.
THEREAFTER...PRESSURE PATTERN...AND AS A RESULT WINDS...BECOME
LIGHT AND ERRATIC THIS EVENING...BEFORE A BIT BETTER DEFINED
NORTHWEST FLOW DEVELOPS AROUND OR AFTER MIDNIGHT. EXPECT A LIGHTER
ONSHORE FLOW AT SEA BREEZE TERMINALS WITH VRB AROUND 5 KT
ELSEWHERE FROM 23-00Z THROUGH 03-05Z.
OUTLOOK FOR 12Z SUNDAY THROUGH WEDNESDAY...HI PRES OVER THE REGION
THROUGH WED WITH MAINLY VFR CONDITIONS. A WEAK CDFNT SUN NIGHT/MON
TIME FRAME. ATTM FRONT LOOKS DRY WITH A CHANCE FOR MVFR CIGS AT
TIMES WITH NELY FLOW BEHIND THE FRONT.
&&
.MARINE...
THE AREA REMAINS SANDWICHED BETWEEN INLAND RIDGE OF HIGH PRESSURE
AND AN OFFSHORE LOW EAST OF THE CAROLINAS. THIS WILL KEEP A FAIRLY
PERSISTENT NE-E FLOW IN PLACE. WINDS WILL CONTINUE TO GRADUALLY
DIMINISH TODAY...BUT SEAS SHOULD REMAIN ABOVE SCA THRESHOLDS INTO
SUN. HAVE UNDERCUT WAVEWATCH III...BUT WILL KEEP 4 TO 6 FT ON OCEAN
WATERS TODAY AND 3 TO 5 FT TONIGHT INTO SUNDAY.
THE PERSISTENT EASTERLY COMPONENT TO THE WINDS...A WEAK EASTERLY
SWELL AND LARGE BREAKING WAVES WILL RESULT IN A MODERATE RISK OF RIP
CURRENTS ALONG NEW YORK ATLANTIC BEACHES TODAY.
AN EXTENDED PERIOD OF SCA CONDITIONS IS LIKELY TO RETURN TO THE
OCEAN WATERS AFTER COLD FROPA ON MON...AS THE AREA ONCE AGAIN
BECOMES SANDWICHED BETWEEN ANOTHER STRONG INLAND HIGH...AND A
COASTAL LOW DEVELOPING ALONG THE SOUTHEAST COAST...WITH A PERSISTENT
NE-E FLOW OVER THE WATERS KEEPING MAX OCEAN SEAS 5+ FEET.
&&
.HYDROLOGY...
NO SIGNIFICANT RAINFALL EXPECTED.
&&
.TIDES/COASTAL FLOODING...
LATEST DATA SHOWING WATER LEVELS ARE BETWEEN 0 AND 0.75 FT ABOVE
ASTRONOMICAL. NO PROBLEMS FORESEEN - THOUGH WILL CONTINUE TO
MONITOR.
THE TIDE CYCLE OF CONCERN IS MIDDAY HIGH TIDE CYCLE...WHICH IS
THE HIGHER OF THE TWO DAILY HIGH TIDES. ASTRONOMICAL TIDES REMAIN
HIGH...AND A DEPARTURE OF ONLY ABOUT 1.0 FT IS NEEDED TO REACH
MINOR COASTAL FLOODING BENCHMARKS. FEEL THAT WE WILL FALL SHORT OF
THIS TODAY DUE TO THE COMBINATION OF A MORE NORTHEAST FLOW THIS
MORNING AND A DECREASING WIND SPEED AS THE DAY PROGRESSES. THE
DEPARTURES FOR THE HIGH TIDE CYCLE OVERNIGHT WERE LESS THAN
YESTERDAY...AND EXPECT THE DECREASING DEPARTURE THEME TO CONTINUE.
MOST LOCALES WILL REMAIN SAFELY BELOW (0.5 FT OR MORE) MINOR
BENCHMARKS. HOWEVER...WE COULD COME CLOSE IN THE NASSAU SOUTH SHORE
BACK BAYS.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 4 PM EDT SUNDAY
FOR ANZ350-353-355.
&&
$$
SYNOPSIS...PW
NEAR TERM...JST/PW
SHORT TERM...PW
LONG TERM...MAS
AVIATION...JST
MARINE...
HYDROLOGY...
TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION...UPDATE
NWS MARQUETTE MI
720 PM EDT SUN SEP 21 2008
UPDATED FOR 00Z TAF ISSUANCE
.SYNOPSIS...
18Z WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS SHOWED TROUGHING
FROM THE NE PACIFIC INTO THE NORTHWESTERN U.S....RIDGING FROM THE
WESTERN GREAT LAKES INTO SOUTH CENTRAL CANADA...AND TROUGHING OVER
SE CANADA. SUBSIDENCE UNDER THE UPPER RIDGE HAS GENERALLY PREVENTED
ANY PCPN FROM OCCURRING OVER THE WESTERN GREAT LAKES...EXCEPT FOR
MAYBE SOME SPRINKLES OVER WESTERN LAKE SUPERIOR AS SEEN ON RADAR
IMAGERY. THESE SPRINKLES ARE ASSOCIATED WITH A BAND OF MID-LEVEL
FRONTOGENESIS AND ACCAS...WHICH STRETCHES FROM NW ONTARIO INTO
WESTERN LAKE SUPERIOR. OTHER CLOUDS OF THE LOW STRATUS VARIETY COVER
SOUTH CENTRAL UPPER MI ACROSS CENTRAL LAKE MI AND CENTRAL LOWER MI.
THE STRATUS HAS BEEN VERY STUBBORN TO MIX OUT...AND THE 16Z TAMDAR
SOUNDING FROM RHI SHOWS WHY WITH A STRONG INVERSION AT 900MB.
HOWEVER...THE MOISTURE PROFILE AND OBSERVATIONS FROM IMT INDICATE
THAT THE DECK HAS THINNED FROM 1500 FT TO AROUND 600 FT NOW...
SUGGESTING MIXING IS HAVING AN IMPACT. VISIBLE SATELLITE NOW
INDICATING HOLES IN THE STRATUS. AT THE SFC...1032MB HIGH PRESSURE
IS OVER EASTERN ONTARIO. SE FLOW AROUND THE HIGH IS GRADUALLY
BRINGING WARMER AIR INTO UPPER MI...WITH 850MB TEMPS PER RUC
ANALYSIS OF 11C AT IWD AND 7C AT ERY. LACK OF SIGNIFICANT WIND HAS
PREVENTED MIXING TO THIS LEVEL. STRONGER SOUTHERLY WINDS ARE LURKING
OFF TO THE WEST ACROSS THE PLAINS...WHICH ARE OCCURRING AHEAD OF A
COLD FRONT ALONG THE LEE OF THE ROCKIES. SOME SHOWERS AND
THUNDERSTORMS ARE ALSO AHEAD OF THE FRONT IN CENTRAL SOUTH DAKOTA.
DEWPOINTS IN THE UPPER 50S/LOW 60S CAN BE SEEN SPREADING NORTHWARD
AHEAD OF THE FRONT AS WELL.
&&
.SHORT TERM (TONIGHT AND MONDAY)...
UPPER TROUGH OVER THE NORTHWEST U.S. WILL BE LIFTING TO THE
NORTHEAST DURING THE NEXT 24 HOURS...CAUSING THE UPPER RIDGE AXIS
WHICH EXTENDS FROM SE MN INTO CENTRAL SASKATCHEWAN TO MOVE OVER
UPPER MI AROUND 18Z. AS THIS RIDGE AXIS MOVES CLOSER TONIGHT AND
WARM ADVECTION INCREASES IN RESPONSE TO THE DIURNAL EFFECTS OF THE
LOW LEVEL JET...THE MID CLOUDS OVER WESTERN LAKE SUPERIOR INTO NW
ONTARIO MAY EXPAND SOME INTO UPPER MI. THE BEST EXPANSION...AND
POSSIBLE PCPN...SHOULD BE CONFINED TO FAR NORTHERN LAKE SUPERIOR
INTO NORTHERN ONTARIO AS INDICATED BY 850MB THETA-E ADVECTION AND
MOISTURE TRANSPORT VECTORS. CLOUDS OVER SOUTH CENTRAL UPPER MI AND
CENTRAL LOWER MI ARE SOMEWHAT CONCERNING...SINCE THEY HAVE STRUGGLED
TO DISSIPATE. WILL GO UNDER THE ASSUMPTION THAT THEY WILL AT LEAST
BECOME SCATTERED BY THE TIME THE SUN DISSIPATES. AS THE WINDS TURN A
BIT MORE SOUTHERLY...THE CLOUDS SHOULD IMPACT THE CENTRAL AND
EASTERN U.P.. THEREFORE...SKY COVER FORECAST IS GENERALLY MOSTLY
CLOUDY FOR MUCH OF UPPER MI...EXCLUDING THE FAR WESTERN U.P.. DID
ADD SOME PATCHY FOG AS WELL...IN THE EVENT THE LOW CLOUDS DISSIPATE
MORE AND THAT MORE MOISTURE WILL BE BROUGHT UP INTO THE CWA. PATCHY
FOG IS ASSIGNED TO THE AREAS WITH THE LIGHTEST WINDS...WHICH IN THIS
CASE IS THE SOUTH CENTRAL U.P.. REGARDING LOW TEMPERATURES...COOLEST
READINGS EXPECTED IN THE AREAS WITH LIGHT WINDS...BUT CLOUDS AND
MORE MOISTURE SHOULD PREVENT TEMPS FROM DROPPING AS LOW AS LAST
NIGHT. PREVIOUS LOW TEMPERATURE FORECAST SEEMS REASONABLE.
ON MONDAY...WARM ADVECTION MID CLOUDS...AND WHATEVER LOW CLOUDS
MIGHT BE AROUND...WILL PUSH EASTWARD THROUGH THE DAY WITH THE RIDGE
AXIS BUILDING IN. SOME HIGH CLOUDS MAY ALSO ENTER THE
PICTURE...ASSOCIATED WITH THE CONVECTION IN CENTRAL SOUTH DAKOTA
THAT MODELS PROG MOVING INTO UPPER MI. THICKER CLOUD COVER
ASSOCIATED WITH HEIGHT FALLS ON THE BACK SIDE OF THE RIDGE AXIS WILL
MOVE INTO FAR WESTERN UPPER MI LATE. NO PCPN IS FORECAST...THOUGH
THERE MAY BE SOME DIURNAL DRIVEN CONVECTION OVER NORTH CENTRAL WI
CLOSE TO THE BORDER AS INDICATED BY THE GFS/NAM QPF FIELDS. THIS
CONVECTION MAKES SENSE AS WELL... LOOKING TO THE SOUTH OVER NRN IL
WHERE THE MOISTURE IS COMING FROM (CONVECTION OCCURRING NORTH OF
BLOOMINGTON/NORMAL IL). WITH 850MB TEMPS AROUND 12C AND A SOUTHERLY
BREEZE...TEMPERATURES WILL END UP WARMER THAN TODAY...PERHAPS 5
DEGREES OR SO. ONLY SLIGHT ADJUSTMENTS WERE MADE TO THE PREVIOUS
HIGH TEMPERATURE FORECAST.
&&
.LONG TERM (MON NIGHT THROUGH NEXT SUN)...
SOUTHERLY FLOW AHEAD OF WEDNESDAY/S FRONTAL PASSAGE WILL YIELD A
WARM MONDAY NIGHT AS TEMPS ONLY DROP INTO THE LOW TO UPPER 50S. FOR
TUESDAY...INCREASING CLOUD COVER WILL KEEP HIGHS IN THE LOW TO MID
70S...UPPER 60S ALONG THE LAKE INFLUENCED NORTH SHORE OF LAKE
MICHIGAN. 850 TEMPS AROUND 14C WOULD SUGGEST HIGHS IN THE UPPER 70S
TO NEAR 80 WITH MINIMAL CLOUD COVER. THINK CLOUDS WILL KEEP TEMPS IN
CHECK THOUGH. BY TUESDAY AFTN/EVENING...ATTENTION TURNS TO
PRECIPITATION CHANCES OUT WEST. GIVEN MODELS SLOWER TRENDS NOTED BY
PREVIOUS SHIFT...DIDN/T FEEL COMFORTABLE EXTENDING HIGHER POPS TOO
FAR EAST...THOUGH 15Z SREF WOULD SUGGEST THAT EXTENDING HIGHER POPS
INTO MARQUETTE AND MENOMINEE COUNTIES WOULD BE FAIRLY SAFE. WILL LET
NEXT SHIFT TOY WITH THIS. WITH ALL THAT IN MIND...KEPT LIKELY POPS
OVER FAR WESTERN LAKE SUPERIOR FOR THE AFTERNOON. BY THE EVENING
HOURS...MODEL GUIDANCE SUGGESTS DIMINISHING TREND IN PRECIPITATION
AS THE FEATURE MOVES EAST ACROSS THE FA. BECAUSE THIS APPEARS TO
OCCUR MORE OFTEN THAN NOT...DECIDED TO ONLY INCLUDE POPS UP TO 50S
IN THE WESTERN ZONES...AND NO HIGHER THAN 30 FOR THE CENTRAL AND
EAST. STRONG SUBSIDENCE AND DRYING BEHIND FRONT WILL ALLOW FOR
PRECIPITATION TO END IN THE LATE MORNING ACROSS THE WEST HALF AND IN
THE EAST BY EARLY EVENING. AGAIN WILL HAVE TO WATCH IF MODELS
CONTINUE TO TREND SLOWER WITH FRONT FOR TIMING THE EXIT OF PRECIP.
LOWERED MIN TEMPS FOR WEDNESDAY NIGHT BEHIND THE FRONT. PWAT/S DROP
TO AROUND A HALF INCH...THIS ALONG WITH INCREASING ANTICYCLONIC
FLOW/MINIMAL CLOUD COVER WILL ALLOW TEMPS TO FALL INTO THE LOW 40S
IN PLACES...PERHAPS EVEN COOLER IF AIRMASS VERIFIES DRIER THAN IS
CURRENTLY PROGGED. THE NEXT FEATURE OF INTEREST IS A FRONT PROGGED
TO PASS THROUGH THE FA SOMETIME EARLY NEXT WEEKEND. ALOT OF
UNCERTAINTY WITH THE TIMING OF THIS FEATURE AND THEREAFTER. KEPT
FCST THE SAME FOR THE EXTENDED PERIODS...DAYS 4 THROUGH 7 AS A
RESULT. POTENTIAL TROPICAL WAVE CURRENTLY NEAR PUERTO RICO INTERACTS
WITH LONGWAVE PATTERN FOR LATE NEXT WEEKEND. AS A RESULT LONG RANGE
MODELS PROVIDE DIFFERING SOLUTIONS...THOUGH BOTH HINT AT COOLER
WEATHER BY MID NEXT WEEK.
&&
.AVIATION (FOR THE 00Z TAF ISSUANCE)...
LINGERING SC OVER THE CNTRL U.P. WL IMPACT BOTH SITES THRU THE
EVNG...WITH MVFR CIGS AT SAW. OTRW...SLY FLOW ON THE WRN FLANK OF HI
PRES RDG TO THE E SHOULD DRAW MSTR/LO CLD NOW APRNT OVER LK MI/LWR
MI N TO BRING SOME FOG INTO SAW...WHICH WL LIFT INTO A SC DECK ON
MON MRNG AFT SUNRISE BEFORE DAYTIME HTG/MIXING BREAKS UP THIS LO
CLD. DOWNSLOPE NATURE OF THIS FLOW SHOULD RESTRICT FOG/LO CLD
DVLPMNT AT CMX. PLAN ON VFR CONDITIONS MON AFTN AFT ANY MRNG LO CLD
MIXES OUT.
&&
.MARINE (FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)...
HIGH PRESSURE OVER EASTERN ONTARIO WILL MOVE TO THE EAST...REACHING
NEW ENGLAND MONDAY NIGHT. SOUTHERLY WINDS ON THE BACK SIDE OF THE
HIGH ARE EXPECTED TO INCREASE ON CENTRAL AND EASTERN LAKE SUPERIOR
TO 15 TO 25 KT...AND GENERALLY STAY THAT WAY THROUGH MONDAY. SOUTH
WINDS WILL INCREASE ACROSS ALL OF LAKE SUPERIOR MON NIGHT INTO TUE
AS A COLD FRONT APPROACHES FROM THE PLAINS. LOOK FOR SPEEDS TO REACH
15 TO 30 KT...WITH THE HIGHEST WINDS ON EASTERN LAKE SUPERIOR TUE
AFTERNOON AND TUE NIGHT. AS THE FRONT CROSSES TUE NIGHT...WINDS
SWITCH TO THE SOUTHWEST AND WEST...WITH SPEEDS UP TO 25
KT...ESPECIALLY OVER NORTH CENTRAL LAKE SUPERIOR LATE TUE NIGHT INTO
WED. AN AREA OF HIGH PRESSURE SHOULD BUILD ACROSS LAKE SUPERIOR WED
NIGHT BEHIND THE FRONT TO LOWER WINDS BELOW 20 KT. AS THIS HIGH
HEADS TO THE EAST THURSDAY...EXPECT SOUTHERLY WINDS TO INCREASE
AGAIN WITH SPEEDS UP TO 30 KT POSSIBLE THU NIGHT AND FRI...STRONGEST
ON EASTERN LAKE SUPERIOR.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...NONE.
LAKE SUPERIOR...NONE.
LAKE MICHIGAN...NONE.
&&
$$
SYNOPSIS/SHORT TERM...AJ
LONG TERM...PEARSON
AVIATION...KC
MARINE...AJ
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
348 PM EDT SUN SEP 21 2008
.SYNOPSIS...
18Z WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS SHOWED TROUGHING
FROM THE NE PACIFIC INTO THE NORTHWESTERN U.S....RIDGING FROM THE
WESTERN GREAT LAKES INTO SOUTH CENTRAL CANADA...AND TROUGHING OVER
SE CANADA. SUBSIDENCE UNDER THE UPPER RIDGE HAS GENERALLY PREVENTED
ANY PCPN FROM OCCURRING OVER THE WESTERN GREAT LAKES...EXCEPT FOR
MAYBE SOME SPRINKLES OVER WESTERN LAKE SUPERIOR AS SEEN ON RADAR
IMAGERY. THESE SPRINKLES ARE ASSOCIATED WITH A BAND OF MID-LEVEL
FRONTOGENESIS AND ACCAS...WHICH STRETCHES FROM NW ONTARIO INTO
WESTERN LAKE SUPERIOR. OTHER CLOUDS OF THE LOW STRATUS VARIETY COVER
SOUTH CENTRAL UPPER MI ACROSS CENTRAL LAKE MI AND CENTRAL LOWER MI.
THE STRATUS HAS BEEN VERY STUBBORN TO MIX OUT...AND THE 16Z TAMDAR
SOUNDING FROM RHI SHOWS WHY WITH A STRONG INVERSION AT 900MB.
HOWEVER...THE MOISTURE PROFILE AND OBSERVATIONS FROM IMT INDICATE
THAT THE DECK HAS THINNED FROM 1500 FT TO AROUND 600 FT NOW...
SUGGESTING MIXING IS HAVING AN IMPACT. VISIBLE SATELLITE NOW
INDICATING HOLES IN THE STRATUS. AT THE SFC...1032MB HIGH PRESSURE
IS OVER EASTERN ONTARIO. SE FLOW AROUND THE HIGH IS GRADUALLY
BRINGING WARMER AIR INTO UPPER MI...WITH 850MB TEMPS PER RUC
ANALYSIS OF 11C AT IWD AND 7C AT ERY. LACK OF SIGNIFICANT WIND HAS
PREVENTED MIXING TO THIS LEVEL. STRONGER SOUTHERLY WINDS ARE LURKING
OFF TO THE WEST ACROSS THE PLAINS...WHICH ARE OCCURRING AHEAD OF A
COLD FRONT ALONG THE LEE OF THE ROCKIES. SOME SHOWERS AND
THUNDERSTORMS ARE ALSO AHEAD OF THE FRONT IN CENTRAL SOUTH DAKOTA.
DEWPOINTS IN THE UPPER 50S/LOW 60S CAN BE SEEN SPREADING NORTHWARD
AHEAD OF THE FRONT AS WELL.
&&
.SHORT TERM (TONIGHT AND MONDAY)...
UPPER TROUGH OVER THE NORTHWEST U.S. WILL BE LIFTING TO THE
NORTHEAST DURING THE NEXT 24 HOURS...CAUSING THE UPPER RIDGE AXIS
WHICH EXTENDS FROM SE MN INTO CENTRAL SASKATCHEWAN TO MOVE OVER
UPPER MI AROUND 18Z. AS THIS RIDGE AXIS MOVES CLOSER TONIGHT AND
WARM ADVECTION INCREASES IN RESPONSE TO THE DIURNAL EFFECTS OF THE
LOW LEVEL JET...THE MID CLOUDS OVER WESTERN LAKE SUPERIOR INTO NW
ONTARIO MAY EXPAND SOME INTO UPPER MI. THE BEST EXPANSION...AND
POSSIBLE PCPN...SHOULD BE CONFINED TO FAR NORTHERN LAKE SUPERIOR
INTO NORTHERN ONTARIO AS INDICATED BY 850MB THETA-E ADVECTION AND
MOISTURE TRANSPORT VECTORS. CLOUDS OVER SOUTH CENTRAL UPPER MI AND
CENTRAL LOWER MI ARE SOMEWHAT CONCERNING...SINCE THEY HAVE STRUGGLED
TO DISSIPATE. WILL GO UNDER THE ASSUMPTION THAT THEY WILL AT LEAST
BECOME SCATTERED BY THE TIME THE SUN DISSIPATES. AS THE WINDS TURN A
BIT MORE SOUTHERLY...THE CLOUDS SHOULD IMPACT THE CENTRAL AND
EASTERN U.P.. THEREFORE...SKY COVER FORECAST IS GENERALLY MOSTLY
CLOUDY FOR MUCH OF UPPER MI...EXCLUDING THE FAR WESTERN U.P.. DID
ADD SOME PATCHY FOG AS WELL...IN THE EVENT THE LOW CLOUDS DISSIPATE
MORE AND THAT MORE MOISTURE WILL BE BROUGHT UP INTO THE CWA. PATCHY
FOG IS ASSIGNED TO THE AREAS WITH THE LIGHTEST WINDS...WHICH IN THIS
CASE IS THE SOUTH CENTRAL U.P.. REGARDING LOW TEMPERATURES...COOLEST
READINGS EXPECTED IN THE AREAS WITH LIGHT WINDS...BUT CLOUDS AND
MORE MOISTURE SHOULD PREVENT TEMPS FROM DROPPING AS LOW AS LAST
NIGHT. PREVIOUS LOW TEMPERATURE FORECAST SEEMS REASONABLE.
ON MONDAY...WARM ADVECTION MID CLOUDS...AND WHATEVER LOW CLOUDS
MIGHT BE AROUND...WILL PUSH EASTWARD THROUGH THE DAY WITH THE RIDGE
AXIS BUILDING IN. SOME HIGH CLOUDS MAY ALSO ENTER THE
PICTURE...ASSOCIATED WITH THE CONVECTION IN CENTRAL SOUTH DAKOTA
THAT MODELS PROG MOVING INTO UPPER MI. THICKER CLOUD COVER
ASSOCIATED WITH HEIGHT FALLS ON THE BACK SIDE OF THE RIDGE AXIS WILL
MOVE INTO FAR WESTERN UPPER MI LATE. NO PCPN IS FORECAST...THOUGH
THERE MAY BE SOME DIURNAL DRIVEN CONVECTION OVER NORTH CENTRAL WI
CLOSE TO THE BORDER AS INDICATED BY THE GFS/NAM QPF FIELDS. THIS
CONVECTION MAKES SENSE AS WELL... LOOKING TO THE SOUTH OVER NRN IL
WHERE THE MOISTURE IS COMING FROM (CONVECTION OCCURRING NORTH OF
BLOOMINGTON/NORMAL IL). WITH 850MB TEMPS AROUND 12C AND A SOUTHERLY
BREEZE...TEMPERATURES WILL END UP WARMER THAN TODAY...PERHAPS 5
DEGREES OR SO. ONLY SLIGHT ADJUSTMENTS WERE MADE TO THE PREVIOUS
HIGH TEMPERATURE FORECAST.
&&
.LONG TERM (MON NIGHT THROUGH NEXT SUN)...
SOUTHERLY FLOW AHEAD OF WEDNESDAY/S FRONTAL PASSAGE WILL YIELD A
WARM MONDAY NIGHT AS TEMPS ONLY DROP INTO THE LOW TO UPPER 50S. FOR
TUESDAY...INCREASING CLOUD COVER WILL KEEP HIGHS IN THE LOW TO MID
70S...UPPER 60S ALONG THE LAKE INFLUENCED NORTH SHORE OF LAKE
MICHIGAN. 850 TEMPS AROUND 14C WOULD SUGGEST HIGHS IN THE UPPER 70S
TO NEAR 80 WITH MINIMAL CLOUD COVER. THINK CLOUDS WILL KEEP TEMPS IN
CHECK THOUGH. BY TUESDAY AFTN/EVENING...ATTENTION TURNS TO
PRECIPITATION CHANCES OUT WEST. GIVEN MODELS SLOWER TRENDS NOTED BY
PREVIOUS SHIFT...DIDN/T FEEL COMFORTABLE EXTENDING HIGHER POPS TOO
FAR EAST...THOUGH 15Z SREF WOULD SUGGEST THAT EXTENDING HIGHER POPS
INTO MARQUETTE AND MENOMINEE COUNTIES WOULD BE FAIRLY SAFE. WILL LET
NEXT SHIFT TOY WITH THIS. WITH ALL THAT IN MIND...KEPT LIKELY POPS
OVER FAR WESTERN LAKE SUPERIOR FOR THE AFTERNOON. BY THE EVENING
HOURS...MODEL GUIDANCE SUGGESTS DIMINISHING TREND IN PRECIPITATION
AS THE FEATURE MOVES EAST ACROSS THE FA. BECAUSE THIS APPEARS TO
OCCUR MORE OFTEN THAN NOT...DECIDED TO ONLY INCLUDE POPS UP TO 50S
IN THE WESTERN ZONES...AND NO HIGHER THAN 30 FOR THE CENTRAL AND
EAST. STRONG SUBSIDENCE AND DRYING BEHIND FRONT WILL ALLOW FOR
PRECIPITATION TO END IN THE LATE MORNING ACROSS THE WEST HALF AND IN
THE EAST BY EARLY EVENING. AGAIN WILL HAVE TO WATCH IF MODELS
CONTINUE TO TREND SLOWER WITH FRONT FOR TIMING THE EXIT OF PRECIP.
LOWERED MIN TEMPS FOR WEDNESDAY NIGHT BEHIND THE FRONT. PWAT/S DROP
TO AROUND A HALF INCH...THIS ALONG WITH INCREASING ANTICYCLONIC
FLOW/MINIMAL CLOUD COVER WILL ALLOW TEMPS TO FALL INTO THE LOW 40S
IN PLACES...PERHAPS EVEN COOLER IF AIRMASS VERIFIES DRIER THAN IS
CURRENTLY PROGGED. THE NEXT FEATURE OF INTEREST IS A FRONT PROGGED
TO PASS THROUGH THE FA SOMETIME EARLY NEXT WEEKEND. ALOT OF
UNCERTAINTY WITH THE TIMING OF THIS FEATURE AND THEREAFTER. KEPT
FCST THE SAME FOR THE EXTENDED PERIODS...DAYS 4 THROUGH 7 AS A
RESULT. POTENTIAL TROPICAL WAVE CURRENTLY NEAR PUERTO RICO INTERACTS
WITH LONGWAVE PATTERN FOR LATE NEXT WEEKEND. AS A RESULT LONG RANGE
MODELS PROVIDE DIFFERING SOLUTIONS...THOUGH BOTH HINT AT COOLER
WEATHER BY MID NEXT WEEK.
&&
.AVIATION (FOR THE 18Z TAF ISSUANCE)...
CLOUD DECK OVER THE SOUTH CENTRAL U.P. CONTINUES TO BE STUBBORN IN
MIXING OUT...AND HAS ENTERED SAW DURING THE PAST TWO HOURS WITH THE
WINDS TURNING SOUTHEAST. CLOUD DECK IS THINNER ON LATEST AIRCRAFT
SOUNDINGS...SUGGESTED NOW ONLY AROUND 600 FT COMPARED TO 1500 FT AT
13Z. THEREFORE...THE CLOUDS SHOULD BEGIN TO BREAK UP WITHIN A FEW
MORE HOURS...AND SO THE TAF FORECAST FOR SAW ONLY INDICATES A TEMPO
BKN DECK...ESPECIALLY SINCE SAW IS ON THE EDGE OF THE CLOUDS.
OTHERWISE...SOME MID AND HIGH CLOUDS ARE EXPECTED TO AFFECT BOTH TAF
SITES THROUGH THE FORECAST PERIOD. THERE COULD BE SOME RADIATIONAL
MVFR BR DEVELOPING AT SAW LATE TONIGHT WITH LIGHT WINDS AND TEMPS
DROPPING TO THE DEWPOINTS...AND SINCE STATISTICAL GUIDANCE HAS BEEN
PERSISTENT IN INDICATING THE BR...HAVE WENT WITH IT FOR THE
FORECAST.
&&
.MARINE (FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)...
HIGH PRESSURE OVER EASTERN ONTARIO WILL MOVE TO THE EAST...REACHING
NEW ENGLAND MONDAY NIGHT. SOUTHERLY WINDS ON THE BACK SIDE OF THE
HIGH ARE EXPECTED TO INCREASE ON CENTRAL AND EASTERN LAKE SUPERIOR
TO 15 TO 25 KT...AND GENERALLY STAY THAT WAY THROUGH MONDAY. SOUTH
WINDS WILL INCREASE ACROSS ALL OF LAKE SUPERIOR MON NIGHT INTO TUE
AS A COLD FRONT APPROACHES FROM THE PLAINS. LOOK FOR SPEEDS TO REACH
15 TO 30 KT...WITH THE HIGHEST WINDS ON EASTERN LAKE SUPERIOR TUE
AFTERNOON AND TUE NIGHT. AS THE FRONT CROSSES TUE NIGHT...WINDS
SWITCH TO THE SOUTHWEST AND WEST...WITH SPEEDS UP TO 25
KT...ESPECIALLY OVER NORTH CENTRAL LAKE SUPERIOR LATE TUE NIGHT INTO
WED. AN AREA OF HIGH PRESSURE SHOULD BUILD ACROSS LAKE SUPERIOR WED
NIGHT BEHIND THE FRONT TO LOWER WINDS BELOW 20 KT. AS THIS HIGH
HEADS TO THE EAST THURSDAY...EXPECT SOUTHERLY WINDS TO INCREASE
AGAIN WITH SPEEDS UP TO 30 KT POSSIBLE THU NIGHT AND FRI...STRONGEST
ON EASTERN LAKE SUPERIOR.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...NONE.
LAKE SUPERIOR...NONE.
LAKE MICHIGAN...NONE.
&&
$$
SYNOPSIS/SHORT TERM...AJ
LONG TERM...PEARSON
AVIATION...AJ
MARINE...AJ
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
151 PM EDT SUN SEP 21 2008
LATEST UPDATE...AVIATION...
.SYNOPSIS...(345 AM EDT SUN SEP 21 2008)
WE WILL START THE DAY OFF WITH SOME PATCHY EARLY MORNING FOG WHICH
WILL BURN OFF QUICKLY BY MID MORNING. A FEW SHOWERS AND
THUNDERSTORMS ARE POSSIBLE THIS AFTERNOON AND EARLY EVENING NEAR AND
MAINLY SOUTH OF INTERSTATE 96. A HIGH PRESSURE RIDGE TO OUR
NORTHEAST WILL PRODUCE FAIR WEATHER AND SEASONABLY MILD TEMPERATURES
MONDAY AND TUESDAY.
&&
.SHORT TERM...(100 PM EDT SUN SEP 21 2008)
(THIS AFTERNOON THROUGH TUESDAY AFTERNOON)
I HAVE TO SAY I AM A LITTLE CONCERNED FOR THIS AFTERNOON AFTER
LOOKING AT TAMDAR AND GFS AND NAM SOUNDINGS FOR THIS AFTERNOON.
THE FRONT IS CURRENTLY CLEARING VAN BUREN COUNTY (NOON). THERE IS A
CONSIDERABLE AMOUNT OF LOW CLOUDS AROUND. MOSTLY THOSE ARE NORTH OF
INTERSTATE 96. THAT WILL ALLOW FOR DECENT HEATING NEAR INTERSTATE 94
THIS AFTERNOON. SOUNDING (TAMDAR...GFS AND NAM) SUGGEST IF WE CAN
GET TO 76F WE COULD LIFT PARCELS TO 36000 FT AND CLOUD TOPS WOULD BE
NEAR 45000 FT BTW 2 PM AND 8 PM. THERE IS A LITTLE NEGATIVE AREA TO
OVERCOME THOUGH NEAR 5000 FT. THE GFS SOUNDING SHOW AS MUCH AS 1700
J/KG OF CAPE IF WE CAN GET THE PARCELS THROUGH THE CAP. ALL I CAN
SAY AT THIS POINT IS IF WE COULD GET A LAKE BREEZE OVER THE SOUTHERN
CWA (12 NOON SFC LI ALREADY -5C ON MSAS WEST OF I-196 SOUTH OF SOUTH
HAVEN). WE WILL HAVE TO WATCH THIS CLOSELY.
AFTER THAT WE MAY HAVE SOME FOG ISSUES TONIGHT HOWEVER THERE IS A 20
KNOT WIND IN THE BOUNDARY LAYER... THAT SHOULD BE ENOUGH TO KEEP FOG
FROM GETTING TO THICK BUT IT WOULD ALLOW FOR A LOW STATUS DECK. WE
WILL HAVE TO LOOK AT THAT TOO.
HIGH PRESSURE AND FAIR WEATHER WILL RULE MON AFTERNOON THROUGH
TUESDAY.
&&
.LONG TERM...(345 AM EDT SUN SEP 21 2008)
(TUESDAY NIGHT THROUGH SATURDAY)
THE LONG TERM PERIOD LOOKS TO BE MAINLY DRY AND ON THE WARM SIDE OF
NORMAL. TEMPERATURES THROUGH THE PERIOD LOOK TO BE 5-10 DEGREES
ABOVE NORMAL FOR THIS TIME OF YEAR WITH HIGHS IN THE UPPER
70S...POSSIBLY PUSHING 80 DEGREES.
IN TERMS OF PRECIPITATION...THERE APPEARS TO BE TWO TIME FRAMES
WHERE THERE IS A CHANCE IN AN OTHERWISE DRY REGIME (TUES NIGHT/WED
AND FRI NIGHT/SAT). UPPER PATTERN WILL BEGIN THE PERIOD TUESDAY
NIGHT WITH RIDGING. THE RIDGING GRADUALLY BREAKS DOWN INTO A MORE
ZONAL FLOW BY WEDNESDAY NIGHT... PERSISTING THEN INTO THE WEEKEND.
THE PROBLEM WITH PRECIPITATION CHANCES IS THAT ANY UPPER SUPPORT IN
TERMS OF MID LEVEL SHORTWAVE TROUGHS ARE LOCATED WELL NORTH OF THE
AREA. A SHORTWAVE MOVES INTO THE UPPER MIDWEST TUESDAY
NIGHT/WEDNESDAY...PUSHING A FRONTAL BOUNDARY INTO THE AREA. THE
FRONT LOSES PUNCH AS IT DRIFTS AWAY FROM THE UPPER SUPPORT AND
BECOMES PARALLEL TO THE UPPER FLOW. LEFT A CHANCE OF PRECIP IN THE
NORTH ON WEDNESDAY...BUT NOT CONFIDENT THAT MUCH WILL OCCUR. A
SIMILAR SCENARIO DEVELOPS FRIDAY NIGHT/SATURDAY WITH ANOTHER
BOUNDARY SAGGING INTO THE AREA AND WEAKENING. LEFT THESE PERIODS DRY
GIVEN THE UPHILL BATTLE THE PRECIPITATION WILL BE FIGHTING (NO UPPER
SUPPORT AND A LACK OF DEEP MOISTURE).
&&
.MARINE...(345 AM EDT SUN SEP 21 2008)
FAIRLY LIGHT WINDS WITH AN EASTERLY COMPONENT WILL RESULT IN RATHER
MINIMAL WAVE ACTION ACROSS OUR NEARSHORE WATERS THROUGH MONDAY.
&&
.AVIATION...(151 PM EDT SAT SEP 21 2008)
VIS SATELLITE IMAGERY SHOWS LOW CLOUDS AND FOG CONTINUING TO
DISSIPATE. EXPECT SOME CU TO FORM THIS AFTERNOON IN IT/S PLACE.
EXPECTING CU TO DISSIPATE AFTER SUNSET. LIGHT WINDS FROM RIDGE
OVERHEAD AND LOW LEVEL MOISTURE WILL HELP TO PRODUCE FOG AGAIN
OVERNIGHT. EXPECT VSBYS TO FALL TO 2-3 MILES IN MOST PLACES
OVERNIGHT BEFORE RECOVERING MON MORNING.
&&
.HYDROLOGY...(345 AM EDT SUN SEP 21 2008)
VERY LITTLE IF ANY RAINFALL THROUGH THE UPCOMING WEEK WILL REMAIN
QUITE CONDUCIVE TO CONTINUED LOWERING OF RIVER LEVELS ACROSS OUR
HSA.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS: LAURENS
SHORT TERM: WDM
LONG TERM: DUKE
MARINE: LAURENS
AVIATION: 93
HYDROLOGY: LAURENS
AREA FORECAST DISCUSSION...UPDATED
NWS MARQUETTE MI
143 PM EDT SUN SEP 21 2008
UPDATED AVIATION DISCUSSION FOR 18Z TAF ISSUANCE
.DISCUSSION...
SURFACE HIGH IS CURRENTLY CENTERED OVER CENTRAL ONTARIO. PUSH OF
COOLER AIR BEING SHUNTED A BIT MORE EASTWARD THAN SOUTHWARD ACROSS
UPPER MICHIGAN THAN EARLIER THINKING. SHALLOW NATURE OF COOLER AIR
HELPED TO PRODUCE A FAIRLY WIDESPREAD SC DECK NEAR THE WI BORDER
WHICH LIMITED RADIATIONAL COOLING EFFECTS. IN ADDITION...SCT/BKN MID
LEVEL CLOUDS ARE DROPPING SOUTHEASTWARD INTO WESTERN SECTIONS OF THE
AREA. DRY AIR ADVECTION CONTINUE IN THE EAST AND THIS AREA WILL BE
THE MOST SUSCEPTIBLE TO FROST EARLY THIS MORNING.
SFC HIGH WILL CONTINUE TO MOVE EASTWARD TODAY WITH WINDS TURNING TO
A MORE SOUTHERLY DIRECTION ON THE BACK SIDE OF THE HIGH. SCT/BKN MID
LEVEL CLOUDS WILL CONTINUE TO MOVES ACROSS THE AREA TODAY WITH TEMPS
EXPECTED TO BE SEASONABLE IN THE LOW/MID 60S.
WARM ADVECTION REALLY BEGINS TO KICK IN LATE TONIGHT AND ON MONDAY
AS GRADIENT BEGIN TO TIGHTEN BETWEEN DEPARTING SFC HIGH AND LOW
PRESSURE DEVELOPING OVER THE NORTHERN PLAINS AS UPPER TROFFING LIFTS
OUT OF THE WESTERN U.S. EXPECT TEMPERATURES TO REMAIN ABOVE NORMAL
FOR THE FIRST FULL WEEK OF FALL AS MEAN UPPER RIDGING HOLDS STRONG
OVER THE GREAT LAKES.
BEST CHANCE OF RAIN THIS WEEK WILL OCCUR MIDWEEK. WESTERN UPPER TROF
AND ASSOCD SURFACE LOW WILL BE DEFLECTED UP INTO CENTRAL CANADA
DURING THE MIDDLE OF THE WEEK. ASSOCD WEAK COLD FRONT WILL APPROACH
UPPER MI LATE TUESDAY/TUE NIGHT. MODELS APPEAR TO BE TRENDING A BIT
SLOWER WITH THE FRONTAL PROGRESSION. WILL NOT MAKE ANY MAJOR
ADJUSTMENTS TO CURRENT POP FCST FOR TUESDAY BUT LATER SHIFTS MAY
HAVE TO DELAY POPS A LITTLE IF TRENDS CONTINUE. AIRMASS BEHIND FRONT
WILL STILL BE ABOVE NORMAL.
WILL NOT MAKE ANY CHANGES TO THE WED AND BEYOND TIMEFRAME AT THIS
TIME.
&&
.AVIATION (FOR THE 18Z TAF ISSUANCE)...
CLOUD DECK OVER THE SOUTH CENTRAL U.P. CONTINUES TO BE STUBBORN IN
MIXING OUT...AND HAS ENTERED SAW DURING THE PAST TWO HOURS WITH THE
WINDS TURNING SOUTHEAST. CLOUD DECK IS THINNER ON LATEST AIRCRAFT
SOUNDINGS...SUGGESTED NOW ONLY AROUND 600 FT COMPARED TO 1500 FT AT
13Z. THEREFORE...THE CLOUDS SHOULD BEGIN TO BREAK UP WITHIN A FEW
MORE HOURS...AND SO THE TAF FORECAST FOR SAW ONLY INDICATES A TEMPO
BKN DECK...ESPECIALLY SINCE SAW IS ON THE EDGE OF THE CLOUDS.
OTHERWISE...SOME MID AND HIGH CLOUDS ARE EXPECTED TO AFFECT BOTH TAF
SITES THROUGH THE FORECAST PERIOD. THERE COULD BE SOME RADIATIONAL
MVFR BR DEVELOPING AT SAW LATE TONIGHT WITH LIGHT WINDS AND TEMPS
DROPPING TO THE DEWPOINTS...AND SINCE STATISTICAL GUIDANCE HAS BEEN
PERSISTENT IN INDICATING THE BR...HAVE WENT WITH IT FOR THE
FORECAST.
&&
.MARINE (FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)...
HIGH PRESSURE CENTERED OVER ONTARIO WILL DRIFT SOUTHEAST INTO
SOUTHERN QUEBEC AND NEW ENGLAND BY SUNDAY EVENING...AND WILL PERSIST
IN THIS AREA THROUGH WEDNESDAY. THIS FEATURE WILL KEEP WINDS BELOW
20 KNOTS THROUGH MONDAY. APPROACHING COOL FRONT ASSOCIATED WITH LOW
PRESSURE SYSTEM MOVING FROM THE CANADIAN PRAIRIE PROVINCES TOWARD
HUDSON BAY EARLY IN THE WORK WEEK TO TIGHTEN THE PRESSURE GRADIENT
OVER THE WESTERN GREAT LAKES MONDAY EVENING INTO TUESDAY. GUSTS TO
30 KNOTS POSSIBLE TUESDAY WITH WINDS GRADUALLY DIMINISHING WEDNESDAY
INTO THURSDAY AS THE COOL FRONT MOVES IN.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...NONE.
LAKE SUPERIOR...NONE.
LAKE MICHIGAN...NONE.
&&
$$
DISCUSSION...MZ
AVIATION...AJ
MARINE...RJT
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
100 PM EDT SUN SEP 21 2008
LATEST UPDATE...SHORT TERM...
.SYNOPSIS...(345 AM EDT SUN SEP 21 2008)
WE WILL START THE DAY OFF WITH SOME PATCHY EARLY MORNING FOG WHICH
WILL BURN OFF QUICKLY BY MID MORNING. A FEW SHOWERS AND
THUNDERSTORMS ARE POSSIBLE THIS AFTERNOON AND EARLY EVENING NEAR AND
MAINLY SOUTH OF INTERSTATE 96. A HIGH PRESSURE RIDGE TO OUR
NORTHEAST WILL PRODUCE FAIR WEATHER AND SEASONABLY MILD TEMPERATURES
MONDAY AND TUESDAY.
&&
.SHORT TERM...(100 PM EDT SUN SEP 21 2008)
(THIS AFTERNOON THROUGH TUESDAY AFTERNOON)
I HAVE TO SAY I AM A LITTLE CONCERNED FOR THIS AFTERNOON AFTER
LOOKING AT TAMDAR AND GFS AND NAM SOUNDINGS FOR THIS AFTERNOON.
THE FRONT IS CURRENTLY CLEARING VAN BUREN COUNTY (NOON). THERE IS A
CONSIDERABLE AMOUNT OF LOW CLOUDS AROUND. MOSTLY THOSE ARE NORTH OF
INTERSTATE 96. THAT WILL ALLOW FOR DECENT HEATING NEAR INTERSTATE 94
THIS AFTERNOON. SOUNDING (TAMDAR...GFS AND NAM) SUGGEST IF WE CAN
GET TO 76F WE COULD LIFT PARCELS TO 36000 FT AND CLOUD TOPS WOULD BE
NEAR 45000 FT BTW 2 PM AND 8 PM. THERE IS A LITTLE NEGATIVE AREA TO
OVERCOME THOUGH NEAR 5000 FT. THE GFS SOUNDING SHOW AS MUCH AS 1700
J/KG OF CAPE IF WE CAN GET THE PARCELS THROUGH THE CAP. ALL I CAN
SAY AT THIS POINT IS IF WE COULD GET A LAKE BREEZE OVER THE SOUTHERN
CWA (12 NOON SFC LI ALREADY -5C ON MSAS WEST OF I-196 SOUTH OF SOUTH
HAVEN). WE WILL HAVE TO WATCH THIS CLOSELY.
AFTER THAT WE MAY HAVE SOME FOG ISSUES TONIGHT HOWEVER THERE IS A 20
KNOT WIND IN THE BOUNDARY LAYER... THAT SHOULD BE ENOUGH TO KEEP FOG
FROM GETTING TO THICK BUT IT WOULD ALLOW FOR A LOW STATUS DECK. WE
WILL HAVE TO LOOK AT THAT TOO.
HIGH PRESSURE AND FAIR WEATHER WILL RULE MON AFTERNOON THROUGH
TUESDAY.
&&
.LONG TERM...(345 AM EDT SUN SEP 21 2008)
(TUESDAY NIGHT THROUGH SATURDAY)
THE LONG TERM PERIOD LOOKS TO BE MAINLY DRY AND ON THE WARM SIDE OF
NORMAL. TEMPERATURES THROUGH THE PERIOD LOOK TO BE 5-10 DEGREES
ABOVE NORMAL FOR THIS TIME OF YEAR WITH HIGHS IN THE UPPER
70S...POSSIBLY PUSHING 80 DEGREES.
IN TERMS OF PRECIPITATION...THERE APPEARS TO BE TWO TIME FRAMES
WHERE THERE IS A CHANCE IN AN OTHERWISE DRY REGIME (TUES NIGHT/WED
AND FRI NIGHT/SAT). UPPER PATTERN WILL BEGIN THE PERIOD TUESDAY
NIGHT WITH RIDGING. THE RIDGING GRADUALLY BREAKS DOWN INTO A MORE
ZONAL FLOW BY WEDNESDAY NIGHT... PERSISTING THEN INTO THE WEEKEND.
THE PROBLEM WITH PRECIPITATION CHANCES IS THAT ANY UPPER SUPPORT IN
TERMS OF MID LEVEL SHORTWAVE TROUGHS ARE LOCATED WELL NORTH OF THE
AREA. A SHORTWAVE MOVES INTO THE UPPER MIDWEST TUESDAY
NIGHT/WEDNESDAY...PUSHING A FRONTAL BOUNDARY INTO THE AREA. THE
FRONT LOSES PUNCH AS IT DRIFTS AWAY FROM THE UPPER SUPPORT AND
BECOMES PARALLEL TO THE UPPER FLOW. LEFT A CHANCE OF PRECIP IN THE
NORTH ON WEDNESDAY...BUT NOT CONFIDENT THAT MUCH WILL OCCUR. A
SIMILAR SCENARIO DEVELOPS FRIDAY NIGHT/SATURDAY WITH ANOTHER
BOUNDARY SAGGING INTO THE AREA AND WEAKENING. LEFT THESE PERIODS DRY
GIVEN THE UPHILL BATTLE THE PRECIPITATION WILL BE FIGHTING (NO UPPER
SUPPORT AND A LACK OF DEEP MOISTURE).
&&
.MARINE...(345 AM EDT SUN SEP 21 2008)
FAIRLY LIGHT WINDS WITH AN EASTERLY COMPONENT WILL RESULT IN RATHER
MINIMAL WAVE ACTION ACROSS OUR NEARSHORE WATERS THROUGH MONDAY.
&&
.AVIATION...(742 AM EDT SAT SEP 21 2008)
VERY COMPLEX/DIFFICULT AVIATION SCENARIO THIS MORNING...AS LOW
CLOUDS AND FOG SURGE SOUTHWEST ACROSS THE TAF SITES. VLIFR
CONDITIONS ARE SURGING TOWARD KAZO AND KBTL AT THIS TIME...WITH
VLIFR CONDITIONS IN PLACE AT KGRR AND KJXN. MOISTURE HAS SAGGED INTO
THE AREA BEHIND A WEAK COLD FRONT AND THIS HAS SET THE STAGE FOR
STRATUS AND FOG FORMATION. LOW CLOUDS AND FOG WILL NOW BEGIN TO
DISSIPATE WITH SUNRISE NOW HAVING OCCURRED. THE FOG/STRATUS IS
FAIRLY FORMIDABLE THOUGH SO THINK IT WILL HANG ON A FEW HOURS BEFORE
BURNING OFF. EXPECT A PRETTY SOLID IMPROVEMENT DURING THE MID TO
LATE MORNING HOURS. THE AFTERNOON SHOULD BE VFR FOR THE MOST
PART...WITH THE MORNING LOW CLOUDS LIFTING INTO A BROKEN CUMULUS
DECK BETWEEN 3500-5000FT. STRAY CHANCE FOR A SHOWER OR THUNDERSTORM
AT ALL THE TAF SITES LATE IN THE AFTERNOON AND EARLY EVENING...BUT
TOO SMALL TO PUT IN THE TAFS AT THIS TIME. AT THIS POINT...HAVE VFR
CONDITIONS IN THE TAFS OVERNIGHT...BUT HINTING AT SOME FOG
REDEVELOPMENT WITH THE 6SM BR WORDING.
&&
.HYDROLOGY...(345 AM EDT SUN SEP 21 2008)
VERY LITTLE IF ANY RAINFALL THROUGH THE UPCOMING WEEK WILL REMAIN
QUITE CONDUCIVE TO CONTINUED LOWERING OF RIVER LEVELS ACROSS OUR
HSA.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS: LAURENS
SHORT TERM: WDM
LONG TERM: DUKE
MARINE: LAURENS
AVIATION: DUKE
HYDROLOGY: LAURENS
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
1028 AM EDT SAT SEP 20 2008
.SYNOPSIS...
HIGH PRESSURE WILL BE THE DOMINATE WEATHER FEATURE OVER THE NORTH
COUNTRY TODAY...WITH SEASONABLY MILD TEMPERATURES AND MAINLY SUNNY
SKIES. A WEAK COLD FRONT WILL CROSS THE REGION LATE TONIGHT INTO
THE FIRST HALF OF SUNDAY WITH LITTLE FANFARE...OTHER THAN AN
INCREASE IN CLOUDS AND A FEW LIGHT SHOWERS. STRONG HIGH PRESSURE
THEN RETURNS WITH FAIR AND DRY WEATHER FOR MUCH OF NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1028 AM EDT SATURDAY...MINOR UPDATE THIS MORNING...MAINLY TO
REFLECT LATEST TRENDS IN TEMPERATURES ACROSS THE AREA. SFC HIGH
PRESSURE CURRENTLY ORIENTED ALONG THE NORTHEASTERN SEABOARD WILL
ALLOW LIGHT TO MODERATE SOUTH/SOUTHWEST FLOW TO CONTINUE ACROSS THE
AREA TODAY UNDER MAINLY SUNNY SKIES. SOME HIGH AND THIN CLOUDS WILL
TRAVERSE NORTHERN/WESTERN AREAS TODAY...BUT WITH LITTLE IMPACT.
CURRENT HYSPLIT BACK-TRAJECTORY ANALYSIS FROM 500-1500M AND AVBL
ACARS DATA FROM CYOW/CYUL THIS MORNING STILL SUPPORT MAX TEMPS IN
THE U60S TO L70S AREA WIDE. PER LATEST SFC OBS...THESE VALUES REMAIN
ON TRACK.
BY TONIGHT...INCR CLD COVER BY NGTFALL FROM APPROACHING FRNT EXPECTED
TO WORK IN FROM THE ST LAW VALLEY. THIS BACKDOOR FRNT IS MOISTURE-
STARVED BUT SHOULD TRIGGER OFF A FEW LGT RW...ESPECIALLY FOR
NORTHERN ZONES. HAVE COMTINUED MENTION OF FG IN VALLEY LOCALES
ALONG WITH SOME PTCHY FROST IN HIR ELEV.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY/...
AS OF 350 AM EDT SATURDAY...FRNT BEGINS TO FALL APART OVER THE
REGION BY SUN MORNING...AS STRONG SFC RIDGE BEGINS TO PUSH EAST FROM
THE GREAT LKS REGION. LINGERING CLDS/PRECIP WILL ERODE BY MORNING HRS
FROM W TO E...W/ POSSIBLILITY OF CLD COVR REMAINING OVER E VT DUE
TO ENE WINDS SETTING UP OVER AREA MON MORNING. 850 TEMPS ON CAA
FROM N SIDE OF RIDGE WILL RANGE FROM 2C-4C...KEEPING EXPECTED
HIGHS BLW NORMAL.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
AS OF 350 AM EDT SATURDAY...SFC RIDGE WILL CREST OVERHD MON NGT
AND SLIDE SLOWLY EAST OFF THE COAST RIGHT THRU FRIDAY. DURING THIS
TIME THE CWA WILL SEE A GENERAL INCR TREND IN TEMPS AS SSW WINDS
WORK INTO THE AREA. NEXT SHOT AT PRECIPITATION WILL BE THURSDAY
NGT AS WARM FRNT LIFTS OVER THE AREA...FOLLOWED BY CD FRNT LATE
FRIDAY NGT. EXPECTING BREAK IN PRECIP BETWEEN FRNTS...SO WILL
BRING IN DRY PERIOD. W/ INFLUENCE OF RIDGE IN PLACE OVER THE
REGION...DRY AIRMASS WILL KEEP QPF DOWN ACROSS THE ENTIRE AREA.
&&
.AVIATION /14Z SATURDAY THROUGH WEDNESDAY/...
THROUGH 12Z SUNDAY...AN ELONGATED AREA OF SURFACE HIGH PRESSURE
EXTENDING FROM NOVA SCOTIA SWWD ACROSS THE GULF OF MAINE INTO
SOUTHERN NEW ENGLAND IS CONTRIBUTING TO LIGHT TO MODERATE
SOUTHERLY WINDS ACROSS THE CHAMPLAIN VLY. MOST OUTLYING AREAS ARE
DECOUPLED UNDER MOSTLY CLEAR SKIES...BUT ANTICIPATE BTV TO
CONTINUE WITH SOUTH WINDS AT 5-10 KTS THROUGH 12Z. PATCHY DENSE
FOG IS POSSIBLE TONIGHT IN THE SHELTERED VALLEYS...MITIGATED ONLY
BY INCREASING HIGH CLOUDS DURING THE PRE-DAWN HOURS...WHICH WILL
LIMIT RADIATIONAL COOLING SLIGHTLY. HAVE INCLUDED SOME VSBY
REDUCTION IN THE TAFS AT MPV/SLK/MSS THROUGH 11-12Z THIS MORNING.
DURING THE DAYLIGHT HOURS SATURDAY...LOOKING AT WIDESPREAD SOUTH
TO SOUTHWESTERLY WINDS AROUND 10 KTS WITH GUSTS UP TO 20 KTS
DURING THE 15-21Z TIME FRAME AS PBL BECOMES WELL MIXED. VFR
CONDITIONS ARE OTHERWISE EXPECTED WITH JUST INCREASING CIRRUS
CLOUDS. A COLD FRONT APPROACHING FROM THE NW AFTER 00Z WILL RESULT
IN INCREASING CLOUDS IN THE 4-6KFT LAYER AND POSSIBLE LIGHT RAIN
SHOWERS AT KMSS AND KSLK BEGINNING AROUND 04Z. LIGHT SHOWERS ARE
POSSIBLE AT THE REMAINING TAF SITES AFTER 06Z. WINDS WILL SHIFT
FROM SW-NW WITH FROPA AFTER 06Z...WITH DEVELOPING MVFR/ISOLD IFR
CEILINGS FOLLOWING FRONTAL PASSAGE TOWARD DAYBREAK ON SUNDAY AS
FRONT SHIFTS SOUTHWARD ACROSS THE REGION.
12Z SUNDAY THROUGH WEDNESDAY...CLOUDS DECREASE SUNDAY MORNING WITH
A RETURN TO VFR CONDITIONS AND GENERALLY LIGHT WINDS FOR THE VAST
MAJORITY OF THE FORECAST PERIOD. A LARGE AREA OF SURFACE HIGH
PRESSURE WILL DRIFT SLOWLY SEWD ACROSS THE AREA DURING THE TIME
FRAME WITH GOOD AVIATION WX CONDITIONS EXPECTED. CLIMATOLOGICALLY
FAVORED DENSE RADIATIONAL FOG IS LIKELY EACH MORNING FROM 06-12Z AT
MPV AND POSSIBLE ALSO AT KMSS AND KSLK. OTHERWISE...NO AVIATION WX
PROBLEMS ANTICIPATED.
&&
.EQUIPMENT...
HAVE HAD SOME WX RADIO TRANSMITTER PROBLEMS FROM THE MT MANSFIELD
SITE THAT COVERS MUCH OF THE REGION. BACK UP AND RUNNING NOW BUT
QUALITY IS STILL SLIGHTLY DEGRADED. THE GOOD NEWS IS THAT WITHIN A
WEEK OR TWO WE SHOULD BE UP AND RUNNING WITH A NEW/MORE POWERFUL
ANTENNA.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...JMG
NEAR TERM...JMG/JN
SHORT TERM...JN
LONG TERM...JN
AVIATION...BANACOS
EQUIPMENT...BTV
|