AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
230 PM PDT TUE OCT 2 2007
.SYNOPSIS...
DRY WEST FLOW ALOFT WILL KEEP THE WEATHER FAIR THROUGH WEDNESDAY.
UPPER LEVEL LOW PRESSURE WILL BRING COOLING AND AN INCREASING MARINE
LAYER FOR MORE LOW CLOUDS AND FOG WEST OF THE MOUNTAINS DURING THE
NIGHTS AND MORNINGS THURSDAY AND FRIDAY. LOCALLY WINDY IN THE
MOUNTAINS AND DESERTS AT TIMES THURSDAY AND FRIDAY. FAIR AND WARMER
THIS WEEKEND UNDER HIGH PRESSURE THEN COOLER WITH AN INCREASING
MARINE LAYER AGAIN EARLY NEXT WEEK.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES.
.SHORT TERM (TODAY-FRI)...
SKIES WERE MOSTLY CLEAR TODAY EXCEPT FOR PATCHY FOG IN SW SAN DIEGO
COUNTY EARLY THIS MORNING. EARLY AFTERNOON ACARS SOUNDINGS INDICATED
AN INVERSION BASED BELOW 1000 FT WITH. OFFSHORE GRADIENTS FROM THE N
WITH ABOUT -6 MB SAN-TPH AND WEAK ONSHORE TO THE E.
ANY SIGNIFICANT MOISTURE FROM THE REMNANTS OF TROPICAL STORM
JULIETTE IS EXPECTED TO REMAIN SE OF OUR AREA WITH DRY WLY FLOW
ALOFT. WEAKENING OFFSHORE FLOW WILL KEEP SKIES GENERALLY CLEAR
THROUGH WED AFTERNOON EXCEPT FOR PERHAPS A FEW PATCHES OF STRATUS
NEAR THE SRN SAN DIEGO COAST LATE TONIGHT AND WED MORNING. AN UPPER
TROUGH APPROACHING FROM THE NW WILL CAUSE THE MARINE LAYER TO
REDEVELOP WED NIGHT INTO THU MORNING BUT LOW CLOUDS AND FOG WILL
STILL BE MAINLY CONFINED TO THE COASTAL AREAS. THE MARINE LAYER WILL
DEEPEN MORE THU NIGHT WITH STRATUS GETTING INTO THE COASTAL MOUNTAIN
SLOPES. THERE COULD BE LOCAL DRIZZLE FROM THE DEEPER MARINE LAYER
THU NIGHT AND FRI MORNING. COOLER THU AND FRI. INCREASING WINDS
ALOFT AND STRONGER ONSHORE FLOW WILL CAUSE LOCAL STRONG GUSTY WINDS
AT TIMES IN THE MOUNTAINS AND DESERTS THU AND FRI WITH WINDS NEAR
ADVISORY STRENGTH IN THE MOUNTAINS THU NIGHT.
&&
.LONG TERM (SAT-TUE)...
AN UPPER RIDGE WILL DEVELOP THROUGH SUN. OFFSHORE FLOW SAT WILL
WEAKEN SUN. THIS WILL BRING FAIR WEATHER WITH WARMER DAYS AND
LIMITED MARINE LAYER CLOUDINESS. ANOTHER UPPER TROUGH WILL BRING AN
INCREASING MARINE LAYER AND COOLING MON AND TUE.
&&
.AVIATION...
022000Z...A FEW PATCHES OF LOW CLOUDS OR FOG MIGHT FORM AT THE
IMMEDIATE COAST LATE TONIGHT OTHERWISE WEAK OFFSHORE FLOW SHOULD
KEEP THE MARINE LAYER OUT TO SEA WITH CLEAR SKIES EXPECTED THROUGH
WEDNESDAY. THERE MAY HOWEVER BE SOME MID AND HIGH LEVEL CLOUDS AT
TIMES IN THE FAR SOUTHERN PORTION OF THE AREA THIS EVENING AND
WEDNESDAY COMING UP FROM THE SOUTH.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
PUBLIC...DVA
AVIATION...CLARK
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
850 PM EDT WED OCT 3 2007
.SYNOPSIS...
THE REGION WILL BE UNDER THE INFLUENCE OF HIGH PRESSURE THROUGH
THE WEEKEND. TEMPERATURES ARE EXPECTED TO AVERAGE ABOVE NORMAL
INTO THE FIRST PART OF NEXT WEEK. A COLD FRONT WILL APPROACH
MIDWEEK.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
...WIDESPREAD FOG EXPECTED ACROSS BALTIMORE/WASHINGTON METROS...
WATER VAPOR LOOP SHOWS A STRONG WAVE LIFTING OVER JAMES
BAY...SHEARING SOUTHWEST INTO THE WESTERN GULF OF MEXICO. AN UPPER
LOW IS SPINNING OVER THE CENTRAL GULF OF MEXICO. ACARS 400-250MB
WIND OBSERVATIONS REVEAL A WESTERLY 100-150KT JET ACROSS THE
NORTHERN ROCKIES...WHICH TROUGHS NORTH OF THE GREAT LAKES. 19Z
SURFACE ANALYSIS PLACED A STALLING COLD FRONT FROM A 983MB CYCLONE
NEAR JAMES BAY SOUTHWEST INTO THE PLAINS. A RIDGE EXTENDED SOUTHWEST
ALONG THE APPALACHIANS...WITH A 1008MB CYCLONE IN THE CENTRAL GULF
OF MEXICO.
LAST NIGHT...WIDE SWATH OF LOW STRATUS LINE THE EAST COAST WITH
ONSHORE FLOW. INLAND COMMUNITIES SAW SOME RADIATIONAL FOG...WITH
DENSE RIVER VALLEY FOG NEAR CBE-MRB-HGR.
AS THE NEXT SYSTEM SHEARS TO THE NORTHEAST (LEAVING CIRRUS OVER THE
NORTHERN FORECAST AREA)...INVERSION HAS LIFTED FROM 1.7KFT TO 2.7KFT
AND HAS SIGNIFICANTLY BEEN ERASED (2145Z KIAD ACARS VS 12Z KIAD
RAOB). THIS SHOULD COMBINE WITH REMAINING MARINE AIRMASS UNDER GOOD
RADIATIONAL COOLING TO PROVIDE WIDESPREAD FOG AND LIMIT INITIAL
STRATUS DEVELOPMENT.
GUIDANCE SUITE FROM THE 15Z SHORT RANGE ENSEMBLES...18Z LWX
WRF-ARW...12Z MET/FWC MOS AND 21Z GFS LAMP...AND 18Z NAM/GFS BUFKIT
FORECAST SOUNDINGS ALL SUPPORT A SIGNIFICANT FOG EVENT. GIVEN WHAT
HAPPENED LAST NIGHT AND CHANGES SUPPORTING MORE FOG THAN STRATUS
TONIGHT...CONFIDENCE IS HIGHER THAN NORMAL. THE AFFECT ON THE
MORNING COMMUTE AND THE LONG RANGE COMMUTERS GETTING THEIR LAST
PLANNING INFORMATION AT THIS TIME IN CONJUNCTION WITH CONFIDENCE HAS
LED TO THE DECISION TO ISSUE A DENSE FOG ADVISORY. LOCATIONS IN
WESTERN MARYLAND AND THE PAN HANDLE OF WEST VIRGINIA WILL SEE LESS
WIDESPREAD FOG IN FAVOR FOR RIVER VALLEY FOG NEAR CBE-MRB-HGR (THIS
MAY BE LIMITED SOME BY CIRRUS HOWEVER).
GUIDANCE WAS TOO COLD FOR LOW TEMPERATURES LAST NIGHT WHERE THE
STRATUS FORMED. SINCE THE THINKING IS LESS STRATUS INITIALLY...WENT
CLOSE TO THE 12Z MET MOS AND ADJUSTED FOR LOCAL BIAS.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/...
FOG EXPECTED TO MIX OUT DURING THE MID MORNING AS THE NOCTURNAL
INVERSION ERODES...LEADING TO DEVELOPMENT OF CU FIELD. CIRRUS FROM
THE NORTHWEST AND SOUTH EXPECTED TO IMPINGE ON FORECAST AREA...SO
CALLED FOR A PARTLY SUNNY SKY.
WITH RECENT WARM SPELL...GUIDANCE HAS BEEN TOO COOL. BUMPED UP
FORECAST TEMPERATURES CLOSER TO 12Z MAVMOS AND ADJUSTED FOR LOCAL
BIAS. LIGHT SOUTHEAST WINDS BASED ON 12Z NAM.
THE RECORD HIGH AT DULLES LOOKS IN RANGE.
&&
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
THE UPPER RIDGE AXIS OFF THE ATLANTIC COAST WILL BEGIN TO
RETROGRADE LATE THURS...AND AGAIN STRENGTHEN OVER THE SOUTHERN
AND CENTRAL APPALACHIAN REGION THRU THE WEEKEND. BEFORE THE UPPER
RIDGE BUILDS ACROSS THE AREA...A FEW WEAK PUSH OF LOW LEVEL MOISTURE
WILL SWING N/WRD OFF THE CAROLINA COAST. THE UPPER RIDGE OFF THE
ATLANTIC COAST WILL WEAKEN ENOUGH ON FRIDAY TO ALLOW A SMALL PUSH OF
MOISTURE UP THE EASTERN SEABOARD INTO PORTIONS OF CNTRL/SRN VA.
STILL...LITTLE IF ANY RAINFALL IS EXPECTED ACROSS THE CWA THRU THE
MIDDLE OF NEXT WEEK.
GFS/ECMWF COMING INTO BETTER AGREEMENT ON THE STRONG UPPER LEVEL
DISTURBANCE ACROSS THE CENTRAL ROCKIES EARLY NEXT WEEK. RUN TO
RUN...LONG RANGE MODELS CONTINUES TO SHOW THE SYSTEM SLOWING DOWN
AND THE TRACK IS EVEN MORE UNCERTAIN. TRENDS ARE BEGINNING TO POINT
TOWARD A E/NE TREK ACROSS OVER MICHIGAN AND THE CENTRAL GREAT LAKES
REGION BY TUES/WED. MON INTO TUES...THE GFS LAYS A WEAK STATIONARY
BOUNDARY JUST TO THE NORTH OF THE AREA...LEFT OVER FROM A WEAK
RESIDUAL AREA FROM A FAST MOVING UPPER DISTURBANCE MOVING SE ACROSS
NEW ENGLAND ON SUNDAY. WITH THE CURRENT TREK OF THE UPPER LOW...A
STRONG COLD FRONT IS EXPECTED TO APPROACH THE AREA TUES/WED...
WEAKENING BEFORE REACHING THE MID ATLANTIC LATE WED/THURS.
&&
.AVIATION /01Z THURSDAY THROUGH MONDAY/...
GOOD MIXING OCCURRED THIS AFTERNOON...AS INVERSION LIFTED FROM
1.7KFT TO 2.7KFT AND HAS SIGNIFICANTLY BEEN ERASED (2145Z KIAD ACARS
VS 12Z KIAD RAOB). THIS WILL REDUCE STRATUS COVERAGE...BUT WITH
MARINE AIRMASS IN PLACE...EXPECT WIDESPREAD DENSE FOG DEVELOPMENT
AROUND METRO HUBS AND KMRB (RIVER VALLEY) LATE TONIGHT. EXPECT
IMPROVEMENT DURING THE MID MORNING AS THE NOCTURNAL INVERSION IS
ERASED.
THRU THE END OF THE WEEK...NO ISSUES W/ WIND OR SKY COVER WITH THE
UPPER RIDGE CONTINUING TO INFLUENCE THE REGION FROM JUST OFF THE
ATLANTIC COAST. A SMALL SURGE OF MOISTURE IS EXPECTED FROM THE SOUTH
ON FRIDAY...THOUGH WILL LIKELY DISSIPATE AS IT APPROACHES THE MID
ATLANTIC. THE HIGH PRESSURE AREA BUILDS BACK IN ACROSS THE EASTERN
SEABOARD EARLY NEXT WEEK...WITH A POSSIBLE FRONTAL PASSAGE DURING
THE MIDDLE OF NEXT WEEK.
&&
.MARINE...
MOST SIGNIFICANT ISSUE IS FOG DEVELOPMENT OVERNIGHT. MARINERS WILL
NOTICE BEST FOG COVERAGE AND WORST VISIBILITIES WILL BE WITHIN
INLETS AND OBSCURING THE COASTLINE. VISIBILITIES EXPECTED TO IMPROVE
DURING THE MID MORNING.
SOUTHERLY WINDS 5-10KTS BEING OBSERVED THIS EVENING...EXPECTED TO
SLACKEN OVERNIGHT UNDER INFLUENCE OF SURFACE RIDGE. AS THE RIDGE
MOVES OFF THE COAST TOMORROW...EXPECT WINDS TO BECOME SOUTHEAST
AROUND 10KTS.
NO WIND ISSUES THRU THE WEEKEND...WITH ONLY WEAK SOUTHEASTERLY
CHANNELING INTO THE BAY FRI/SAT AS THE HIGH WEAKENS OFF THE COAST
AND SHIFTS BACK TOWARD THE WEST. THE BEGINNING OF NEXT WEEK LOOKS
QUIET...WITH A COLD FRONT EXPECTED TO CROSS THE AREA BY THE END OF
NEXT WEEK.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...DENSE FOG ADVISORY FROM 4 AM TO 9 AM EDT THURSDAY FOR DCZ001.
MD...DENSE FOG ADVISORY FROM 4 AM TO 9 AM EDT THURSDAY FOR
MDZ003>007-009>011-013-014-016>018-501-502.
VA...DENSE FOG ADVISORY FROM 4 AM TO 9 AM EDT THURSDAY FOR VAZ041-
042-050>057.
WV...DENSE FOG ADVISORY FROM 4 AM TO 9 AM EDT THURSDAY FOR
WVZ051>053.
MARINE...NONE.
&&
$$
SYNOPSIS...HTS
NEAR TERM...ROGOWSKI
SHORT TERM...ROGOWSKI
LONG TERM...GMS
AVIATION...ROGOWSKI/GMS
MARINE...ROGOWSKI/GMS
AREA FORECAST DISCUSSION
NWS GAYLORD MI
1031 AM EDT TUE OCT 2 2007
.UPDATE...PRETTY SIZABLE HOLE IN THE LOW CLOUDS HAS ALREADY OPENED
UP ALONG THE M-33/M-65 CORRIDORS IN NE LOWER MI. THERE ARE ALSO
BREAKS ALONG THE LAKE MI COAST NEAR AND SOUTH OF MBL. ELSEWHERE...
FOG AND STRATUS CONTINUE WITH SLOW IMPROVEMENT IN CIGS/VSBYS. CIRRUS
IS ALREADY ADVECTING INTO THE REGION OVER TOP OF THE LOW STUFF...AND
IN ADVANCE OF TONIGHT/S SYSTEM. CLOUD/TEMP TRENDS ARE THE CLEAR MAIN
CONCERN FOR THE REST OF THE DAY.
NW LOWER AND EASTERN UPPER MI ARE THE MAIN QUESTION MARKS...AND
MAINLY FROM AN AVIATION STANDPOINT. THERE/S ENOUGH CIRRUS MOVING IN
FOR A MOSTLY CLOUDY FORECAST...NO MATTER WHAT THE LOW CLOUDS DO. AM
INCLINED TO THINK THE CLEARING OF LOW CLOUDS IN NW LOWER/EASTERN
UPPER WILL BE SLOW...THANKS TO THAT CLOUD COVER COMING OVER THE TOP
HINDERING MIXING/HEATING. SHOULD STILL SEE THE STRATUS RISE/BREAK UP
TO STRATOCU...BUT IT WON/T HAPPEN TIL LATE AFTERNOON IN SOME
SPOTS. EARLIER FORECASTS LARGELY ACCOUNTED FOR THIS...AGAIN MAIN
TWEAKS HAVE BEEN TO AVIATION PRODUCTS. DUE TO CLOUD TRENDS...WILL
TWEAK MAX TEMPS DOWN IN THE WEST AND UP IN THE EAST.
ZOLTOWSKI
&&
.AVIATION...ISSUED 728 AM TUE OCT 2...WIDESPREAD IFR CONDITIONS WITH
PATCHY DRIZZLE AND AREAS OF FOG WITH CIGS BASED AOA 1000 FEET THIS
MORNING WILL BECOME MVFR INTO THE AFTERNOON AS STRENGTHENING
SOUTHERLY WINDS PROMOTE MIXING WITH DRIER AIR ADVANCING IN ALOFT.
TAMDAR SOUNDINGS SHOW LOW LEVEL MOISTURE UPSTREAM REMAINS ROUGHLY
1.5KFT THICK WHICH SHOULD SUSTAIN BKN-OVC 020-030 CIGS THROUGH MUCH
OF THE DAY WITH OVERCAST CONDITIONS THROUGH THE MORNING. A PERIOD OF
VFR IS POSSIBLE LATER THIS AFTERNOON...BUT MAINLY IN THE EVENING AS
WINDS RAMP UP JUST OFF THE SURFACE AND LLWS DEVELOPING OVER THE
REGION BY MIDNIGHT. SFC COOL FRONT...A WIND SHIFT AND RAIN SHOWERS
ENTER THE FORECAST TOWARD DAYBREAK. SMD
&&
.PREV DISCUSSION... /ISSUED 451 AM EDT TUE OCT 2 2007/
DISCUSSION...SFC/RUC/SATELLITE/RADAR AND UPPER AIR ANALYSIS
SHOWING MID LEVEL TROUGH SWINGING EAST OF THE REGION WITH THE
DEEPER MID LEVEL MOISTURE GOING ALONG FOR THE RIDE. 00Z APX
SOUNDING LIKELY MUCH LESS DRIER NOW ABOVE 850MB. MID AND UPPER
50S SFC TD`S STILL HANGING AROUND...WITHIN ILL-DEFINED LOW
PRESSURE/TROUGH AXIS SITUATED ACROSS NRN MICHIGAN...BUT THIS
MOISTURE IS STILL DEEP ENOUGH TO MAKE STRATUS...RATHER THAN FOG
THE DOMINANT WEATHER ATTM. EVIDENCE OF THIS STILL RATHER DEEP LOW
LEVEL MOISTURE COMES FROM THE VERY LIGHT RETURNS...OR PATCHY
DRIZZLE...SEEN ON RADAR. THIS THICK LOW LEVEL CLOUD COVER HAS KEPT
TEMPS IN THE UPPER 50S TO LOWER 60S...SO WE ARE ENJOYING A RATHER
MILD OCTOBER NIGHT.
FORECAST CONCERNS...FOG EARLY THIS MORNING...CLEARING POTENTIAL
FOR THIS AFTERNOON...THEN PRECIP CHANCES WITH NEXT FRONTAL SYSTEM
ARRIVING LATE TONIGHT INTO TOMORROW MORNING.
TODAY...DEEPER MID LEVEL MOISTURE WILL CONTINUE TO SLIDE EAST INTO
THE EARLY MORNING...BUT NOT BEFORE PATCHY DRIZZLE CAN CONTINUE TO
AFFECT A FEW AREAS THIS MORNING. AS THE DEEPER MOISTURE TRACKS
EAST...FOG WILL BECOME MORE OF A CONCERN...PROVIDED IT CAN
DEVELOP BEFORE SUNRISE. THIS LOOKS TO BE THE CASE FOR WESTERN
CHIP/MACK COUNTIES...AND AREAS SOUTH OF GTV BAY...WHERE MOISTURE
SHOULD BE THIN/BUT HIGH ENOUGH IN THE LOWEST 50-100MB FOR FOG TO
BE A CONCERN. ALREADY SEEING CEILINGS DIPPING TO LESS THAN 500
FEET IN THESE PLACES...AND VISBYS WERE LOWEST IN THESE AREAS. WILL
ASSUME THAT THE NEXT FEW HOURS WILL CONTINUE TO EXPERIENCE A
GREATER THREAT FOR 1/2SM OR LESS VISBYS...BUT DO NOT THINK A DENSE
FOG ADVISORY WILL BE WARRANTED DUE TO THE LIMITED WINDOW OF
OPPORTUNITY THROUGH DAYBREAK. MODELS INSIST ON STRIPPING OUT
ENOUGH LOW LEVEL MOISTURE WITH STRENGTHENING SOUTH WINDS TODAY
AHEAD OF OUR NEXT FRONTAL SYSTEM WHICH WILL MAKE IT INTO WISCONSIN
BY LATE THIS AFTERNOON. LOTS OF HIGHER CLOUD SEEN MOVING IN FROM
THE WEST OVERNIGHT...SO EVEN IF THE LOW CLOUDS ERODE QUICKLY BY
MIDDAY...HIGHER LEVEL CLOUDS WILL LIKELY MAKE THE SKY REMAIN
MOSTLY CLOUDY. TEMPERATURES WILL NOT RISE A BUNCH...TOPPING OUT IN
THE MILD UPPER 60S AND LOWER 70S.
TONIGHT AND WEDNESDAY...COOL FRONT WILL ARRIVE IN NRN MICHIGAN
LATE TONIGHT AND INTO WEDNESDAY MORNING. SOUTHERLY FLOW WILL
INCREASE THROUGH THE NIGHT TO 35-40KTS AT 950MB RESULTING IN LLWS
CONCERNS...MILE TEMPS AGAIN OVERNIGHT...AND SMALL CRAFT ADVISORY
CONDITIONS IN SOME OF THE NEARSHORE ZONES. MOISTURE WILL CONTINUE
TO INCREASE OUT AHEAD OF THIS SYSTEM...RESULTING IN MOSTLY CLOUDY
SKIES FOR MOST AREAS. THIS COOL FRONT WILL BE A QUICK ONE...AND
NOT THE MOST POTENT OF SYSTEMS...AS H8-H5 MOISTURE BAND SLOWLY
THINS WITH THE FRONT BY THE TIME IT ARRIVES HERE. THERE REALLY
ISN`T A WELL DEFINED WARM FRONT TO MOVE IN...HOWEVER A MODEST BAND
OF H8-H5 -DIVQ WITH THE MOISTURE SHOULD BE ABLE TO SPARK OFF SOME
RAIN SHOWERS. TIMING WAS HARD TO ARGUE FROM ONGOING FORECAST...IN
KEEPING MAINLY AN AFTER MIDNIGHT RAINFALL. DID TWEAK THE CHANCES
FOR RAIN WHICH LOOKS LIKELY FOR A GOOD PORTION OF THE REGION. THIS
IS ESPECIALLY TRUE FOR THOSE AREAS CLOSER TO LAKE MICHIGAN WHERE
MOISTURE SHOULD BE GREATEST. THE SOUTH WINDS WILL GUST TO 25 KNOTS
OR SO FROM MANISTEE TO SLEEPING BEAR POINT WITH THE HELP OF
COASTAL CONVERGENCE...WITH FUNNELING EFFECTS ACROSS TAWAS. THE
WINDS TURN MORE SW WHICH LOOK TO GET ALL OF THE LAKE MICHIGAN
NEARSHORE ZONES IN PLAY FOR A SMALL CRAFT ADVISORY. HAVE ISSUED
THIS HEADLINE WITH THE 4AM ISSUANCE. SIMILAR GUSTS TO OCCUR WITH
THE FRONTAL PASSAGE WHICH CLEARS MOST OF THE AREA BY MIDDAY
TOMORROW...SO RAN THE HEADLINE THROUGH WEDNESDAY MORNING. LOWS
WILL BE IN THE UPPER 50S TO AROUND 60...WHILE THE HIGHS TOP OUT
IN THE UPPER 60S TO LOWER 70S.
WEDNESDAY NIGHT ONWARD...FRONT WILL BE WELL EAST...AND A MUCH
DRIER AIR MASS MOVES IN OVERHEAD. H8-H5 MOISTURE DROPS TO 15 TO
45 PERCENT (HIGHEST ACROSS EASTERN UPPER /FAR NRN LOWER). WILL KEEP
THINGS PRECIP-FREE UNTIL FRIDAY WHEN A WARM FRONT IS EXPECTED TO
LAY OUT ACROSS EASTERN UPPER FOR A POSSIBLE RETURN FOR A CHANCE OF
SHOWERS. UNTIL THEN...TEMPERATURES WILL REMAIN MILD WITH HIGHS IN
THE 70S...AND LOWS IN THE 50S. NO MAJOR CHANGES IN THIS TIME
PERIOD.
SMD
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
LH...NONE.
LS...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GAYLORD MI
728 AM EDT TUE OCT 2 2007
.AVIATION...WIDESPREAD IFR CONDITIONS WITH PATCHY DRIZZLE AND
AREAS OF FOG WITH CIGS BASED AOA 1000 FEET THIS MORNING WILL
BECOME MVFR INTO THE AFTERNOON AS STRENGTHENING SOUTHERLY WINDS
PROMOTE MIXING WITH DRIER AIR ADVANCING IN ALOFT. TAMDAR SOUNDINGS
SHOW LOW LEVEL MOISTURE UPSTREAM REMAINS ROUGHLY 1.5KFT THICK
WHICH SHOULD SUSTAIN BKN-OVC 020-030 CIGS THROUGH MUCH OF THE DAY
WITH OVERCAST CONDITIOSN THROUGH THE MORNING. A PERIOD OF VFR IS
POSSIBLE LATER THIS AFTERNOON...BUT MAINLY IN THE EVENING AS WINDS
RAMP UP JUST OFF THE SURFACE AND LLWS DEVELOPING OVER THE REGION BY
MIDNIGHT. SFC COOL FRONT...A WIND SHIFT AND RAIN SHOWERS ENTER THE
FORECAST TOWARD DAYBREAK. SMD
&&
.PREV DISCUSSION... /ISSUED 451 AM EDT TUE OCT 2 2007/
DISCUSSION...SFC/RUC/SATELLITE/RADAR AND UPPER AIR ANALYSIS
SHOWING MID LEVEL TROUGH SWINGING EAST OF THE REGION WITH THE
DEEPER MID LEVEL MOISTURE GOING ALONG FOR THE RIDE. 00Z APX
SOUNDING LIKELY MUCH LESS DRIER NOW ABOVE 850MB. MID AND UPPER
50S SFC TD`S STILL HANGING AROUND...WITHIN ILL-DEFINED LOW
PRESSURE/TROUGH AXIS SITUATED ACROSS NRN MICHIGAN...BUT THIS
MOISTURE IS STILL DEEP ENOUGH TO MAKE STRATUS...RATHER THAN FOG
THE DOMINANT WEATHER ATTM. EVIDENCE OF THIS STILL RATHER DEEP LOW
LEVEL MOISTURE COMES FROM THE VERY LIGHT RETURNS...OR PATCHY
DRIZZLE...SEEN ON RADAR. THIS THICK LOW LEVEL CLOUD COVER HAS KEPT
TEMPS IN THE UPPER 50S TO LOWER 60S...SO WE ARE ENJOYING A RATHER
MILD OCTOBER NIGHT.
FORECAST CONCERNS...FOG EARLY THIS MORNING...CLEARING POTENTIAL
FOR THIS AFTERNOON...THEN PRECIP CHANCES WITH NEXT FRONTAL SYSTEM
ARRIVING LATE TONIGHT INTO TOMORROW MORNING.
TODAY...DEEPER MID LEVEL MOISTURE WILL CONTINUE TO SLIDE EAST INTO
THE EARLY MORNING...BUT NOT BEFORE PATCHY DRIZZLE CAN CONTINUE TO
AFFECT A FEW AREAS THIS MORNING. AS THE DEEPER MOISTURE TRACKS
EAST...FOG WILL BECOME MORE OF A CONCERN...PROVIDED IT CAN
DEVELOP BEFORE SUNRISE. THIS LOOKS TO BE THE CASE FOR WESTERN
CHIP/MACK COUNTIES...AND AREAS SOUTH OF GTV BAY...WHERE MOISTURE
SHOULD BE THIN/BUT HIGH ENOUGH IN THE LOWEST 50-100MB FOR FOG TO
BE A CONCERN. ALREADY SEEING CEILINGS DIPPING TO LESS THAN 500
FEET IN THESE PLACES...AND VISBYS WERE LOWEST IN THESE AREAS. WILL
ASSUME THAT THE NEXT FEW HOURS WILL CONTINUE TO EXPERIENCE A
GREATER THREAT FOR 1/2SM OR LESS VISBYS...BUT DO NOT THINK A DENSE
FOG ADVISORY WILL BE WARRANTED DUE TO THE LIMITED WINDOW OF
OPPORTUNITY THROUGH DAYBREAK. MODELS INSIST ON STRIPPING OUT
ENOUGH LOW LEVEL MOISTURE WITH STRENGTHENING SOUTH WINDS TODAY
AHEAD OF OUR NEXT FRONTAL SYSTEM WHICH WILL MAKE IT INTO WISCONSIN
BY LATE THIS AFTERNOON. LOTS OF HIGHER CLOUD SEEN MOVING IN FROM
THE WEST OVERNIGHT...SO EVEN IF THE LOW CLOUDS ERODE QUICKLY BY
MIDDAY...HIGHER LEVEL CLOUDS WILL LIKELY MAKE THE SKY REMAIN
MOSTLY CLOUDY. TEMPERATURES WILL NOT RISE A BUNCH...TOPPING OUT IN
THE MILD UPPER 60S AND LOWER 70S.
TONIGHT AND WEDNESDAY...COOL FRONT WILL ARRIVE IN NRN MICHIGAN
LATE TONIGHT AND INTO WEDNESDAY MORNING. SOUTHERLY FLOW WILL
INCREASE THROUGH THE NIGHT TO 35-40KTS AT 950MB RESULTING IN LLWS
CONCERNS...MILE TEMPS AGAIN OVERNIGHT...AND SMALL CRAFT ADVISORY
CONDITIONS IN SOME OF THE NEARSHORE ZONES. MOISTURE WILL CONTINUE
TO INCREASE OUT AHEAD OF THIS SYSTEM...RESULTING IN MOSTLY CLOUDY
SKIES FOR MOST AREAS. THIS COOL FRONT WILL BE A QUICK ONE...AND
NOT THE MOST POTENT OF SYSTEMS...AS H8-H5 MOISTURE BAND SLOWLY
THINS WITH THE FRONT BY THE TIME IT ARRIVES HERE. THERE REALLY
ISN`T A WELL DEFINED WARM FRONT TO MOVE IN...HOWEVER A MODEST BAND
OF H8-H5 -DIVQ WITH THE MOISTURE SHOULD BE ABLE TO SPARK OFF SOME
RAIN SHOWERS. TIMING WAS HARD TO ARGUE FROM ONGOING FORECAST...IN
KEEPING MAINLY AN AFTER MIDNIGHT RAINFALL. DID TWEAK THE CHANCES
FOR RAIN WHICH LOOKS LIKELY FOR A GOOD PORTION OF THE REGION. THIS
IS ESPECIALLY TRUE FOR THOSE AREAS CLOSER TO LAKE MICHIGAN WHERE
MOISTURE SHOULD BE GREATEST. THE SOUTH WINDS WILL GUST TO 25 KNOTS
OR SO FROM MANISTEE TO SLEEPING BEAR POINT WITH THE HELP OF
COASTAL CONVERGENCE...WITH FUNNELING EFFECTS ACROSS TAWAS. THE
WINDS TURN MORE SW WHICH LOOK TO GET ALL OF THE LAKE MICHIGAN
NEARSHORE ZONES IN PLAY FOR A SMALL CRAFT ADVISORY. HAVE ISSUED
THIS HEADLINE WITH THE 4AM ISSUANCE. SIMILAR GUSTS TO OCCUR WITH
THE FRONTAL PASSAGE WHICH CLEARS MOST OF THE AREA BY MIDDAY
TOMORROW...SO RAN THE HEADLINE THROUGH WEDNESDAY MORNING. LOWS
WILL BE IN THE UPPER 50S TO AROUND 60...WHILE THE HIGHS TOP OUT
IN THE UPPER 60S TO LOWER 70S.
WEDNESDAY NIGHT ONWARD...FRONT WILL BE WELL EAST...AND A MUCH
DRIER AIR MASS MOVES IN OVERHEAD. H8-H5 MOISTURE DROPS TO 15 TO
45 PERCENT (HIGHEST ACROSS EASTERN UPPER /FAR NRN LOWER). WILL KEEP
THINGS PRECIP-FREE UNTIL FRIDAY WHEN A WARM FRONT IS EXPECTED TO
LAY OUT ACROSS EASTERN UPPER FOR A POSSIBLE RETURN FOR A CHANCE OF
SHOWERS. UNTIL THEN...TEMPERATURES WILL REMAIN MILD WITH HIGHS IN
THE 70S...AND LOWS IN THE 50S. NO MAJOR CHANGES IN THIS TIME
PERIOD.
SMD
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
LH...NONE.
LS...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
431 AM EDT TUE OCT 2 2007
.SYNOPSIS...
07Z WATER VAPOR IMAGERY AND RUC 500MB HEIGHT ANALYSIS SHOWED RIDGING
COVERING MUCH OF THE EAST HALF OF THE U.S....EXCLUDING AN UPPER LOW
OVER LAKE ERIE...AND A TROUGH STRETCHING FROM CENTRAL MONTANA INTO
NORTHERN UTAH. QUIET WEATHER CURRENTLY EXISTS ACROSS THE CWA WITH
THE AREA BETWEEN THE UPPER LOW AND TROUGH...WITH THE ONLY ISSUES
BEING IN THE AVIATION DEPARTMENT WITH LOW CLOUDS AND VISIBILITIES
STUCK UNDERNEATH A RADIATIONAL AND COLD FRONTAL INVERSION (SEE 00Z
APX SOUNDING). SO FAR...THE ONLY PLACES AROUND DENSE FOG ADVISORY
CRITERIA ARE ESC...MNM...ISQ AND ERY PER OBS. THESE LOW CLOUDS
EXTEND INTO EASTERN MN...AND HAVE HELPED TO KEEP TEMPERATURES AND
DEWPOINTS UP INTO THE MID TO UPPER 50S. TO THE WEST...LOW PRESSURE
HAS DEVELOPED NEAR PIERRE SOUTH DAKOTA DUE TO DOWNSLOPING FLOW OFF
THE ROCKIES AND HEIGHT FALLS AHEAD OF THE INTERMOUNTAIN WEST TROUGH.
VERY LITTLE IN THE WAY OF PCPN IS OCCURRING ALONG THE LOWS
ASSOCIATED COLD FRONT...WITH MOSTLY HIGH CLOUDS PRESENT. THIS IS DUE
TO A LOT OF LOW AND MID LEVEL DRY AIR AS SEEN ON THE 00Z NORTH
PLATTE NEBRASKA SOUNDING. ANY PCPN AT THE MOMENT WITH THE ENTIRE
TROUGH IS FARTHER WEST OVER UTAH AND COLORADO. ALTHOUGH THE PCPN IS
FAIRLY MINIMAL...THE SYSTEM IS PRODUCING PLENTY OF WIND...WITH
PROFILERS ACROSS NEBRASKA AND WESTERN KANSAS IN THE 40-50KT RANGE AT
850MB. THESE WINDS...MOSTLY FROM THE SSW...ARE TRANSPORTING 850MB
DEWPOINTS OF AROUND 10C NORTHWARD FROM WEST TEXAS AND SW KANSAS PER
00Z RAOBS.
&&
.DISCUSSION...
TODAY AND TONIGHT...MODELS (GFS/NAM/UKMET/CANADIAN) ARE ALL IN GOOD
AGREEMENT WITH REGARDS TO THE PROGRESSION AND TIMING OF THE UPPER
LEVEL TROUGH AND COLD FRONT MOVING EASTWARD. THEY ALL HAVE TRENDED
TOWARDS THE SLOWER IDEA PRESENTED BY THE 00Z NAM/UKMET SHOWN
YESTERDAY. BY 00Z WED...THE TROUGH IS PROGGED TO BE OVER CENTRAL
MINNESOTA WITH THE COLD FRONT IN WESTERN WI. BY 12Z WED...BOTH THE
TROUGH AND FRONT ARE PROGGED TO BE LOCATED OVER EASTERN ONTARIO AND
LOWER MICHIGAN...WITH STRONG DRYING COMING IN BEHIND IT. UNTIL THAT
OCCURS...THE AREA WILL BE UNDER A WARM ADVECTION PATTERN AHEAD OF
THE TROUGH...WHICH SHOULD BRING UP A NARROW ZONE OF 850MB THETA-E
ADVECTION INTO THE CWA. WITHIN THIS ZONE...SHOWERS AND SOME
THUNDERSTORMS ARE EXPECTED TO DEVELOP AS HEIGHT FALLS COME ACROSS
FROM THE UPPER TROUGH. IT APPEARS THIS DEVELOPMENT WILL TAKE PLACE
EARLY THIS AFTERNOON OVER MN/WI AND PERHAPS THE FAR WESTERN
U.P....THEN GRADUALLY MOVE EASTWARD THROUGH THE AFTERNOON AND NIGHT.
BEST CHANCES FOR RAIN APPEARS TO BE TONIGHT...THOUGH...GIVEN THE
SLOWER MOTION PROGGED WITH THE TROUGH/COLD FRONT. TEMPERATURES WILL
HAVE A HARD TIME WARMING WITH ALL THE CLOUD COVER...BUT SOUTHERLY
WINDS SHOULD BE ABLE TO GIVE AT LEAST A 5-10 DEGREE RISE. BUMPED UP
LOWS TONIGHT...PARTICULARLY IN THE EAST DUE TO THE SLOWER MOTION OF
THE FRONT.
WED THROUGH THU...DRY AIR ADVECTION THAT OCCURRED BEHIND TONIGHTS
UPPER TROUGH SHOULD SET THE STAGE FOR QUIET WEATHER DURING THIS
PERIOD. AN UPPER TROUGH CURRENTLY OVER THE EAST PACIFIC IS PROGGED
TO DIG DOWN INTO THE WEST COAST...CAUSING HEIGHT RISES DOWNSTREAM.
THESE HEIGHT RISES WILL PROMPT WARM ADVECTION OVER THE
AREA...HOWEVER GIVEN THE DRY AIRMASS PRESENT...VERY LITTLE CLOUD
COVER IS EXPECTED. ONLY ACROSS ISLE ROYALE AND WESTERN LAKE SUPERIOR
WED NIGHT AND THU IS THERE EXPECTED TO BE PARTLY TO MOSTLY CLOUDY
SKIES...WHERE THE BEST MOISTURE CONVERGENCE IS PROGGED. THE WARM
ADVECTION WILL ALLOW 850MB TEMPS TO CLIMB TO 8C AT 18Z WED AND TO
14C BY 18Z THU. WE SHOULD BE ABLE TO MIX UP TO 850MB ON WED...GIVEN
THE COOLER CONDITIONS...AND THUS ALLOW HIGHS TO REACH THE UPPER 60S
TO LOW 70S. ON THU...GIVEN THE SUN ANGLE...IT MAY BE HARD TO REACH
850MB...AND THUS HAVE ONLY WENT WITH HIGHS IN THE LOW TO MID 70S.
THU NIGHT AND FRI...WARM AND MOIST AIR ADVECTION IS PROGGED TO
INCREASE ACROSS THE PLAINS...UPPER MISSISSIPPI VALLEY AND WESTERN
GREAT LAKES AS THE TROUGH OVER THE WEST COAST CONTINUES TO DIG
TOWARDS THE FOUR CORNERS. LEFT IN SLIGHT CHANCE POPS FOR AFTER 06Z
THU NIGHT FOR THE FAR WESTERN U.P. AND WESTERN LAKE SUPERIOR WHERE
ENOUGH MOISTENING OF THE LOW AND MID LEVELS TAKE PLACE. CONDITIONS
LOOK BETTER FOR PCPN DEVELOPING ON FRI WITH CONTINUED MOISTENING AND
THE PROSPECTS OF A SHRTWV OR SHRTWVS CROSSING...AS INDICATED BY THE
00Z ECMWF/GFS. TO GIVE AN IDEA OF THE MOISTENING...850MB DEWPOINTS
AT IMT CLIMB FROM -4C AT 00Z FRI TO 12C AT 00Z SAT. HAVE INCREASED
POPS TO 40 FOR FRI.
FRI NIGHT THROUGH SUN...THIS PERIOD OF THE FORECAST CAN HAVE A LOT
OF BUST POTENTIAL...WITH UNCERTAINTIES ABOUT HOW THE WESTERN TROUGH
EVOLVES. IT DOES SEEM LIKE...THOUGH...THAT MODELS ARE FOCUSING ONTO
MORE RIDGING ACROSS UPPER MICHIGAN WITH THE ONLY EXCEPTION BEING THE
00Z UKMET WHICH IS VERY PROGRESSIVE WITH THE WESTERN TROUGH. THE
SCENARIO OF MORE RIDGING...WITH A POSSIBLE FRONTAL BOUNDARY OVER THE
AREA SEEMS MORE LIKELY. TO THE SOUTH OF THIS BOUNDARY...WARM AND
HUMID CONDITIONS FOR OCTOBER ARE EXPECTED. NORTH OF THE
BOUNDARY...COOLER WEATHER WITH SHOWERS AND THUNDERSTORMS SEEM LIKELY
WITH 850MB DEWPOINTS AROUND 14C. EITHER WAY...IT WAS NECESSARY TO
RAISE TEMPERATURES UP THROUGH THE PERIOD...WITH A SIGNIFICANT
INCREASE ON FRI NIGHT WITH A WARM FRONTAL BOUNDARY PROGGED TO BE
JUST NORTH OF UPPER MICHIGAN. MORE ADJUSTMENTS TO THE EXTENDED WILL
BE NEEDED.
&&
.AVIATION (FOR THE 06Z TAF ISSUANCE)...
THE STRATUS DECK OVER THE AREA HAS HELPED TO LIMIT FOG FORMATION
THIS EVENING. NEVERTHELESS...CANNOT RULE OUT LOWER STRATUS OR FOG
FORMATION LATER TONIGHT WITH VSBY FALLING AOB 1SM GIVEN ABUNDANT
MOISTURE EVIDENT ON 00Z KSAW TAMDAR SOUNDING IN THE SFC-900 MB
LAYER. STRENGTHENING SRLY FLOW AND DEEPER MIXING TUE AHEAD OF THE
NEXT TROUGH SHOULD HELP LIFT CIGS TO VFR IN THE AFTERNOON. THE BULK
OF THE PCPN WITH THE NEXT SHORTWAVE TROUGH IS EXPECTED TO HOLD OFF
UNTIL UNTIL AROUND 22Z AT KCMX AND 01Z AT KSAW. PCPN WITH SHOWERS
AND POSSIBLY AND A FEW ISOLATED THUNDERSTORMS WILL HELP LOWER
CIGS/VSBYS BACK INTO THE MVFR RANGE.
&&
.MARINE (FOR THE 4 AM LAKE SUPERIOR FCST ISSUANCE)...
NEXT ACTIVE LOW PRES TROUGH WILL RACE E FROM THE PLAINS TODAY AND
CROSS LAKE SUPERIOR TONIGHT. SRLY WINDS WILL RAMP UP IN ADVANCE OF
THIS TROUGH TO GENERALLY 15 TO 25KT...BUT IT`S NOT OUT OF THE
QUESTION THAT A FEW GALE FORCE GUSTS TO 35 KT COULD OCCUR OVER THE E
HALF OF THE LAKE LATE THIS AFTN/EVENING. W GALE FORCE GUSTS TO 35 KT
COULD OCCUR IMMEDIATELY AFTER TROF PASSAGE FROM AROUND THE KEWEENAW
PENINSULA EWD LATE TONIGHT/EARLY WED MORNING. WINDS FOR THE
REMAINDER OF THE FCST (WED AFTN THRU SAT) SHOULD GENERALLY BE IN THE
10 TO 20KT RANGE WITH AN OCCASIONAL PERIOD OF 15 TO 25KT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 11 AM EDT TUESDAY
MIZ004>007-010>014-084-085.
&&
$$
SYNOPSIS/DISCUSSION...AJ
AVIATION...JLB
MARINE...ROLFSON
AREA FORECAST DISCUSSION...UPDATED
NWS MARQUETTE MI
130 AM EDT TUE OCT 2 2007
UPDATED FOR AVIATION DISCUSSION
.UPDATE (ISSUED AT 1030 PM EDT)...
11-3.9MICRON SATELLITE LOOP AND SURFACE OBS INDICATED A LARGE AREA
OF STRATUS OVER THE WESTERN GREAT LAKES IN THE WAKE OF THE DEPARTING
MID LEVEL AND SURFACE LOW OVER LOWER MI. THE 00Z KSAW TAMDAR
SOUNDING SHOWED ABUNDANT SFC-900 MB MOISTURE WITH SIGNIFICANT DRYING
FROM 850 TO 700 MB. EVEN THOUGH THE STRATUS DECK HAS DELAYED THE
ONSET OF SIGNIFICANT FOG...EXPECT THAT THE 900-700 MB DRYING WILL
EVENTUALLY...LIGHT WINDS AND DIURNAL COOLING WILL ALLOW THE STRATUS
AND SOME DENSE FOG DEVELOPMENT OVERNIGHT OVER CNTRL UPPER MI.
SO...THE DENSE FOG ADVISORY WAS LEFT IN PLACE.
.SYNOPSIS...A CLOSED LOW IS OVER SOUTHEAST LOWER MICHIGAN...A ZONAL
FLOW PERSIST FROM MANITOBA EASTWARD...AND A TROUGH EXTENDS FROM
ALBERTA SOUTHWEST INTO CALIFORNIA. A WEAK SHORTWAVE IS SWEEPING
THROUGH THE FORECAST AREA IN THE ZONAL FLOW THROUGH NORTHERN
ONTARIO. SURFACE ANALYSIS DEPICTS A HIGH OVER JAMES BAY...A LOW OVER
CENTRAL QUEBEC WITH A STATIONARY FRONT DRAPED WEST THROUGH CENTRAL
ONTARIO AND CENTRAL MANITOBA...AND A LOW OVER KSSM AREA WITH A COLD
FRONT SAGGING THROUGH LOWER MICHIGAN AND WESTERN OHIO RIVER VALLEY.
TO THE WEST A LOW IS DEVELOPING OVER THE NORTHERN HIGH PLAINS WITH A
ACCOMPANYING FRONTAL SYSTEM OVER THE DAKOTAS.
&&
.SHORT TERM (TONIGHT AND TUE) ISSUED AT 340 PM EDT...
THE MAIN CONCERN WITH THIS FORECAST IS FOG AND PRECIPITATION
POTENTIAL FOR TONIGHT AND TUESDAY.
THE CLOSED LOW WILL SHIFT EAST INTO THE LOWER GREAT LAKES
TONIGHT...WHILE THE TROUGH OVER THE HIGH PLAINS EDGES INTO THE
WESTERN DAKOTAS. THE CLOSED LOW WILL FILL AS IT MOVES TO NEW ENGLAND
ON TUESDAY. THE TROUGH OVER DAKOTAS WILL REACH THE UPPER MISSISSIPPI
RIVER VALLEY ON TUESDAY. A ZONAL FLOW WILL THEN SET UP ACROSS THE
WEST HALF OF THE CONUS. THE LOW OVER EASTERN U.P. WILL WASH OUT AS
IT TRACKS INTO EAST CENTRAL ONTARIO. THE FRONTAL SYSTEM OVER THE
DAKOTAS WILL GET CAUGHT IN THE FLOW AND PUSHED INTO THE U.P. BY
TUESDAY AFTERNOON. A SOUTHERLY FLOW AHEAD OF THIS SYSTEM WILL BRING
WARM AIR INTO THE FORECAST AREA. THE LOCAL REGIONAL WRF MODEL
SHOWING THE SURFACE RH WILL REMAIN AROUND 100 PERCENT TONIGHT ACROSS
MUCH OF THE FORECAST AREA. THIS LOW LEVEL MOISTURE WILL BE TRAPPED
UNDER A SURFACE BASED INVERSION. WIND WILL REMAIN LIGHT...SO
CONDITIONS ARE FAVORABLE FOR CONSIDERABLE FOG FORMATION ACROSS THE
AREA. WILL GO WITH A DENSE FOG ADVISORY FOR TONIGHT. DRY AIR AND
WARMER TEMPERATURES WILL MIGRATE INTO THE AREA ON TUESDAY BURNING
OFF THE FOG. AS THE SHORTWAVE TROUGH AND ASSOCIATED COLD FRONT
SWEEPS ACROSS THE NORTHERN PLAINS INTO THE FORECAST AREA...A THETA-E
RIDGE WILL ACCOMPANY THE FRONT WILL BRING THUNDERSTORMS INTO THE
WESTERN U.P. BY TUESDAY AFTERNOON.
.LONG TERM (TUE NIGHT THROUGH NEXT MON)...
SHORTWAVE TROUGH THAT ENTERS THE REGION ON TUE QUICKLY EXITS LATE
TUE NIGHT. STRONG JET ON FRONT SIDE OF TROUGH WILL KEEP THE TROUGH
MORE POSITIVELY TILTED/PROGRESSIVE AS IT CROSSES THE UPR GREAT
LAKES. GFS/ECMWF/UKMET IN DECENT AGREEMENT INDICATING PCPN WILL EXIT
CWA BY 12Z WED. FOLLOWED THE MAX THETA-E ADVECTION AND NOSE OF H85
JET TO SEE OUTLINE HIGHEST POPS. TRIMMED THUNDER CHANCES SOME AS
GREATEST ML CAPES AND STEEPEST MID LEVEL LAPSE RATES SET UP TO THE
SOUTH OF THE CWA TUE AFTN AND EVENING. OTHERWISE...GRIDS FOR THIS
TIME IN EXCELLENT SHAPE. MADE NO OTHER MAJOR CHANGES WED AND THU. SW
FLOW INCREASING INTO THE REGION WILL LEAD TO A WARMING TREND AND
SINCE PRIMARY FRONTAL BOUNDARY FOCUSING PCPN REMAINS TO THE NORTH OF
CWA...HAVE A DRY FCST THROUGH THU. AFTER THU...DIFFERENCES BEGIN TO
EMERGE IN FCST DETAILS.
COMFORT OF HAVING GOOD AGREEMENT BTWN THE GFS AND ECMWF IS GONE AS
WE GO INTO NEXT WEEKEND. WENT ALONG WITH THE HPC IDEA AND PREFERRED
THE MORE CONSISTENT ECMWF AS IT AGREES WITH CANADIAN/UKMET AND
SOMEWHAT THE ENSEMBLES. GFS JUST APPEARS TOO AGGRESSIVE IN EJECTING
TROUGH FM PACIFIC COAST INTO CNTRL PLAINS RIDGE. EXPERIMENTAL
REFORECAST ENSEMBLE DATA (WHICH IS CORRECTED FOR LONG TERM GFS
BIASES) ALSO DOES NOT AGREE WITH THE GFS RUNS. EXPECT TROUGH TO MOVE
TO CNTRL PLAINS BY 00Z SUN AND SHIFT ACROSS THE GREAT LAKES THROUGH
MON. DESPITE THE OVERALL PREFERENCE OF THE ECMWF...BELIEVE THAT
STRONG JET ENERGY COMING OUT OF THE PLAINS INTO THE SYSTEM AND
PERSISTENT STRONGER SOLUTIONS FM THE GFS COULD LEAD TO A SLIGHTLY
STRONGER SOLUTION THAN ECMWF BY NEXT MON OVER THE GREAT
LAKES. THEREFORE...KEPT TEMPS COOLER THAN GUIDANCE SUN-MON AND
LINGERED CHANCES OF PCPN WITHIN THE CYCLONIC NW FLOW PATTERN IN WAKE
OF THE DEPARTING LOW PRES TROUGH.
&&
.AVIATION (FOR THE 06Z TAF ISSUANCE)...
THE STRATUS DECK OVER THE AREA HAS HELPED TO LIMIT FOG FORMATION
THIS EVENING. NEVERTHELESS...CANNOT RULE OUT LOWER STRATUS OR FOG
FORMATION LATER TONIGHT WITH VSBY FALLING AOB 1SM GIVEN ABUNDANT
MOISTURE EVIDENT ON 00Z KSAW TAMDAR SOUNDING IN THE SFC-900 MB
LAYER. STRENGTHENING SRLY FLOW AND DEEPER MIXING TUE AHEAD OF THE
NEXT TROUGH SHOULD HELP LIFT CIGS TO VFR IN THE AFTERNOON. THE BULK
OF THE PCPN WITH THE NEXT SHORTWAVE TROUGH IS EXPECTED TO HOLD OFF
UNTIL UNTIL AROUND 22Z AT KCMX AND 01Z AT KSAW. PCPN WITH SHOWERS
AND POSSIBLY AND A FEW ISOLATED THUNDERSTORMS WILL HELP LOWER
CIGS/VSBYS BACK INTO THE MVFR RANGE.
&&
.MARINE (FOR THE 4 PM LAKE SUPERIOR FCST ISSUANCE)...
WINDS WILL REMAIN LIGHT THIS EVENING. RESIDUAL MOISTURE FROM THE
RAINS AND A STRONG SURFACE BASE INVERSION WILL GENERATE SOME FOG
OVER LAKE SUPERIOR TONIGHT. AS WARMER TEMPERATURES AND A LITTLE
DRIER AIR MOVES INTO THE AREA AHEAD OF THE NEXT SYSTEM THE FOG WILL
GRADUALLY DIMINISH. AN ACTIVE LOW PRES TROUGH WILL RACE EAST AND
CROSS LAKE SUPERIOR TUE NIGHT. SOUTHERLY WINDS WILL AGAIN BE PUSHED
IN ADVANCE OF THIS TROUGH PRODUCING 25 TO 30 KT WINDS OVER THE LAKE
SUPERIOR. WINDS FOR THE REMAINDER OF THE FORECAST PERIOD SHOULD
GENERALLY BE IN THE 10 TO 20KT RANGE WITH AN OCCASIONAL PERIOD OF 15
TO 25KT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVY UNTIL 11 AM EDT TODAY MIZ004>007-010>014-084-085.
&&
$$
UPDATE...JLB
SYNOPSIS/SHORT TERM...DLG
LONG TERM...JLA
MARINE...DLG
AVIATION...JLB
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