AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
100 PM EDT TUE OCT 14 2008
.MORNING UPDATE...
MADE FEW CHANGES FOR THE LATE MORNING UPDATE. SPRINKLES EARLIER THIS
MORNING ACROSS THE BLUEGRASS REGION DID LITTLE MORE THAN WET THE
PAVEMENT. THOSE HAVE DISSIPATED. PATCHY BROKEN SKIES WITH A FEW
CLEAR AREAS COVER THE FORECAST AREA WITH CEILINGS GENERALLY AROUND 5
TO 7 THOUSAND FEET.
TEMPERATURES ACROSS THE BLUEGRASS ARE CURRENTLY RUNNING A FEW
DEGREES COOLER DUE TO CLOUDS THIS MORNING. THESE WILL CATCH UP WITH
THE REST OF THE CWA THIS AFTERNOON DUE TO PARTIAL CLEARING THIS
AFTERNOON.
SOUTH CENTRAL INDIANA SAW QUITE A BIT OF SUN THIS MORNING...BUT WILL
BECOME PARTLY TO MOSTLY CLOUDY THIS AFTERNOON AS A WEAKENING COLD
FRONT APPROACHES CENTRAL INDIANA.
FORECAST SOUNDINGS MATCH RECENT SDF ACARS MEASUREMENTS. BOTH SHOW A
STRONG MID-LEVEL CAP AT 10K FEET...BUT WITH GOOD INSTABILITY
BENEATH THE CAP. EXPECT AFTERNOON CU TO DEVELOP BUT SPREAD OUT
LATERALLY AS IT REACHES THIS CAP. A FEW SPRINKLES MAY DEVELOP AGAIN
THIS AFTERNOON...BUT THESE SHOULD BE ISOLATED AND THUS MAY KEEP OUT
OF THE FORECAST.
&&
.SHORT RANGE (TODAY AND TONIGHT)...
THE MUCH ANTICIPATED TRANSITION FROM THE HOT TEMPERATURES OF THE
PAST FEW DAYS TO A MORE NORMAL FALL WEATHER PATTERN WILL BEGIN TO
TAKE SHAPE TODAY. AN UPPER LEVEL TROUGH WILL MOVE ACROSS THE GREAT
LAKES REGION AND WILL FORCE THE UPPER RIDGE TO SINK SOUTH INTO THE
GULF COAST STATES. A SURFACE COOL FRONT WILL DROP INTO SOUTHERN
ILLINOIS AND INDIANA AND BECOME NEARLY STATIONARY TONIGHT. IN
ADDITION TO INCREASED CLOUD COVER SOME LIGHT SHOWERS WILL BE
POSSIBLE ALONG THE FRONT TONIGHT SO WE WILL ADD LOW POPS TO SOUTHERN
INDIANA. WITH THE FALLING HEIGHTS AND CLOUD COVER TEMPERATURES THIS
AFTERNOON WILL TOP OUT AROUND 80 DEGREES... STILL SOME 10 TO 15
DEGREES ABOVE NORMAL FOR THE MIDDLE OF OCTOBER. LOWS TONIGHT WILL
HOLD IN THE UPPER 50S AND LOWER 60S.
.LONG TERM (WEDNESDAY THROUGH MONDAY)...
TRICKY LONG TERM PERIOD WITH LIGHT PRECIP CHANCES THAT ARE DIFFICULT
TO TIME. ONLY MINOR TWEAKS MADE TO POPS. AS PREVIOUS FORECASTER
NOTED...THE 12Z ECMWF STILL REMAINS THE WETTEST OF ALL SOLNS SO WILL
DISREGARD AS MOST OTHER GUIDANCE IS NOT NEAR AS ENTHUSIASTIC ABOUT
OUR PRECIP CHANCES.
FIRST A WEAK COLD FRONT WILL AFFECT THE AREA WED/THURS BRINGING SCT
SHOWERS TO THE AREA. LATEST MODEL RUNS ARE GENERALLY IN DECENT
AGREEMENT WITH TIMING...BUT VARY ON INTENSITY. WILL STICK WITH LOW
CHANCE POPS AND LIGHT QPF.
NEXT CHANCE AT PRECIP WILL BE WITH THE UPPER TROUGH MOVING THROUGH
THE AREA ON FRI. 0Z GEM...GFS OP...AND GFS ENSEMBLE ALL KEEP EITHER
ONLY ISLD SHOWERS OR NO SHOWERS OVER THE FORECAST AREA. GEM AND GFS
ENSEMBLES ACTUALLY POINT TO MORE SHOWERS TO OUR S. OVER TN. WILL
CONTINUE SLIGHT CHANCE POPS FOR NOW ALTHOUGH THESE MAY NEED TO BE
CUT.
TEMPS WED WILL BE WARM IN THE UPPER 70S AND LOW 80S. HOWEVER AFTER
THE COLD FRONT MOVES THROUGH EXPECT HIGHS IN THE 60S AND LOW 70S
THU/FRI WITH LOW TEMPS IN THE 40S AND LOW 50S.
SAT THROUGH MON...
MOST CONFIDENT PART OF THE FORECAST...THOUGH THAT MAY NOT BE SAYING
MUCH...IS THAT THIS WEEKEND LOOKS DRY. IF THE FRIDAY TROF CONTINUES
TO SLOW DOWN ANY WE COULD SEE A FEW LINGERING SHOWERS OVER THE BLUE
GRASS SATURDAY MORNING...BUT BY AND LARGE IT LOOKS DRY THIS WEEKEND.
THE NEXT SYSTEM BOTH AT THE SURFACE AND ALOFT WILL EDGE IN FROM THE
WEST EARLY NEXT WEEK BUT WITH MODEL TIMING DIFFERENCES AND LOW
CONFIDENCE WILL GO WITH HPC/S DRY FORECAST FOR MONDAY FOR NOW.
AFTER HIGHS ON WEDNESDAY AROUND THE 80 DEGREE MARK WE WILL COOL DOWN
TO AFTERNOON READINGS AROUND 70 LATER THIS WEEK INTO THE WEEKEND.
&&
.AVIATION (18Z TAFS)...
FORECAST SOUNDINGS SHOW SOME INSTABILITY THIS AFTERNOON AND EVENING
UP TO 10K FEET...ABOVE WHICH A SHARP INVERSION EXISTS. EXPECT PLENTY
OF AFTERNOON CU WITH BASES AROUND 4 TO 6K FEET WHICH WILL BECOME
BROKEN AT TIMES. CLOUDINESS WILL BE GREATEST NORTH OF THE OHIO
RIVER...WHERE POSSIBILITY EXIST FOR SOME SPRINKLES OR VERY LIGHT
SHOWERS. HOWEVER...DO NOT EXPECT SPRINKLES AT ANY TAF SITES.
AFTERNOON CUMULUS WILL ERODE AFTER 22Z...BUT OCCASIONAL PATCHY MID
LEVEL CLOUDS SHOULD CONTINUE THROUGH THE EVENING HOURS.
CIGS AND VISIBILITIES SHOULD STAY VFR THROUGH 12Z WEDNESDAY.
WINDS WILL CONTINUE AROUND 5 MPH FROM THE WEST THROUGH THE EARLY
EVENING HOURS...THEN BACK TO LIGHT SOUTHERLY BY TOMORROW MORNING.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
WEATHER.GOV/LOUISVILLE
SHORT TERM...JSD
LONG TERM....AML
AVIATION.....JSD
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
1051 AM EDT MON OCT 13 2008
.SYNOPSIS...
HIGH PRESSURE TO DOMINATE THE WEATHER THROUGH MUCH OF THE COMING
WEEK. A COLD FRONT IS EXPECTED TO MOVE THROUGH LATE IN THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
S/W TROUGH MOVING ACROSS NEW ENGLAND IS RESPONSIBLE FOR THE EXTENSIVE
MID-HIGH CLOUDS THIS MORNING THAT COVER PARTS OF THE FCST AREA.
GFS RUN FROM YDAY ADVERTISED THIS CLD CVR PRETTY WELL AND SUGGESTS
THAT CLDS SHOULD THIN OUT AS THE AFTERNOON PROGRESSES. HAVE GONE
WITH A P/SUNNY FCST AS MORE BREAKS SHOULD DEVELOP LATER TODAY.
MORNING SOUNDING INDICATES VERY WARM AIR JUST ABV SFC WITH +17C AT
H85. ALTHOUGH FULL MAXT POTENTIAL WONT BE REALIZED DUE TO POOR
MIXING AND CLOUDS...STILL THINK THAT TEMPS WILL BE ABLE TO 80F
BEFORE THE DAY IS OVER.
&&
.SHORT TERM / TUESDAY THROUGH 6 AM TUESDAY/...
LGT AND VRB WINDS TO RETURN THIS EVE AS SFC HIPRES DOMINATES. CLRG
SKIES...LGT WINDS AND DRY AIR ASSOCIATED WITH SFC HIPRES SHUD ALLOW
FOR EFFICIENT RADIATIONAL COOLING AND POTENTIAL FOR PATCHY FOG TNGT.
MINIMA IN MID TO UPR 30S TNGT HIGHER TERRAIN PSBL...MID TO UPR 40S
CNTRL ZONES...AND LOW TO MID 50S ERN ZONES...WHERE UPR LVL CLDS TO
LINGER INTO THIS EVE.
WILL NEED TO MONITOR FOR POTENTIAL FOR LOCALIZED FROST WRN ZONES
AS FCST MINIMA CLOSE TO LCL THRESHOLDS FOR ADZY.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
A DEEP WESTERN CONUS TROUGH AND AMPLIFIED EASTERN CONUS RIDGE HAS
DEVELOPED AT 500MB DURING THE PAST 5 DAYS...AS THE NEXT STRONG
DISTURBANCE MOVES OVER THE WESTERN PACIFIC WATERS WITH RIDGING AHEAD
OF THE SYSTEM OVER THE CENTRAL PACIFIC. WATER VAPOR LOOP SHOWS THE
RIDGE DOMINATING THE EASTERN CONUS...WITH A STRONG DISTURBANCE
BEGINNING TO EXIT THE WESTERN CONUS TROUGH OVER THE UPPER MIDWEST.
SUBSTANTIAL DRY AIR ALOFT IS DEVELOPING OVER THE SOUTHWESTERN CONUS
AS THE TROUGH BEGINS TO ELONGATE. ACARS 400-250MB WIND OBSERVATIONS
REVEAL THAT A 100-125KT JET CARVES A WESTERN CONUS TROUGH
/PARTICULARLY ON THE LEADING EDGE OF THE TROUGH/...AND CURVES
ANTICYCLONICALLY FROM THE HUDSON BAY TO THE CANADIAN MARITIMES.
THE LATE EVENING SURFACE MAP FEATURED A 1032MB HIGH PRESSURE
SYSTEM BUILDING ACROSS THE MID ATLANTIC FROM NEW ENGLAND...WITH
THE WARM/STATIONARY BOUNDARY STRETCHING FROM THE WESTERN GREAT
LAKES SOUTH TO THE GULF STATES THEN EAST OFF THE SOUTH CAROLINA
COAST. THE NEXT COLD FRONT WAS CROSSING THE UPPER MIDWEST AND
PLAINS.
12Z GFS ENSEMBLES AND LAST SEVERAL RUNS OF GFS/EUROPEAN MODELS ARE
IN GENERALLY GOOD AGREEMENT THROUGH THE LONG RANGE. HIGH PRESSURE
SURFACE AND ALOFT WEAKEN DURING THE MIDWEEK AS A DISTURBANCE FROM
THE WESTERN CONUS TROUGH FLATTENS THE RIDGE. THIS SHOULD ALLOW A
COLD FRONT TO GRADUALLY PUSH THROUGH THE REGION DURING THE LATE WORK
WEEK. GIVEN THE ZONAL FLOW ALOFT AND MEAGER CONVERGENCE ALONG THE
BOUNDARY...HAVE LEFT SILENT 20 POPS FOR THIS PERIOD.
SURFACE HIGH PRESSURE WILL BUILD SLOWLY INTO THE REGION NEXT
WEEKEND...WITH THE PASSAGE OF AN UPPER TROUGH. COOL BREEZY
CONDITIONS EXPECTED UNDER CLEARING SKIES.
&&
.AVIATION /15Z MONDAY THROUGH FRIDAY/...
LGT LOW LVL WINDS AND SCT-BKN CI DECK XPCD THRU THIS EVE WITH
PERSISTENCE OF STG UPR RDG AND SFC HIPRES.
HIGH PRESSURE DOMINATES DURING THE EARLY WORK WEEK...WITH PERHAPS
SPOTTY MVFR SUNRISE FOG AT CLIMATOLOGICALLY FAVORED LOCATIONS. WEAK
FRONTAL BOUNDARY DROPS SLOWLY ACROSS THE REGION DURING THE LATTER
PORTION OF THE WORK WEEK...BRINGING A CHANCE OF RAIN /WITH PRIMARILY
MVFR-VFR CONDITIONS/. PRELIMINARY LOOK TOWARD THE WEEKEND SHOWS A
GOOD CHANCE OF GUSTY NORTHWESTERLY WINDS AS THE PRESSURE GRADIENT
INCREASES ON THE LEADING EDGE OF BUILDING HIGH PRESSURE.
&&
.MARINE...
NO MARINE HAZARDS XPCD THRU TNGT AS LGT LOW LVL WINDS AND DRY WX
PERSIST OWING TO STG UPR RDG AND SFC HIPRES.
HIGH PRESSURE WILL PROVIDE RELATIVELY LIGHT WINDS ACROSS THE WATERS
THROUGH MID WEEK. WINDS EXPECTED TO BECOME A BIT STRONGER FROM THE
NORTHWEST OR NORTH LATE DURING THE WORK WEEK WITH THE PASSAGE OF A
COLD FRONT. PRELIMINARY LOOK TOWARD THE WEEKEND SHOWS A GOOD CHANCE
OF SMALL CRAFT ADVISORY WINDS AS THE PRESSURE GRADIENT INCREASES ON
THE LEADING EDGE OF BUILDING HIGH PRESSURE.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.
&&
$$
UPDATE...ROSA
PRODUCTS...KRAMAR/ROGOWSKI
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
309 AM EDT MON OCT 13 2008
.SYNOPSIS...
HIGH PRESSURE TO DOMINATE THE WEATHER THROUGH MUCH OF THE COMING
WEEK. A COLD FRONT IS EXPECTED TO MOVE THROUGH LATE IN THE WEEK.
&&
.NEAR TERM /THROUGH TODAY/...
SFC HIPRES AND STG UPR RDG OVR SERN CONUS TO PERSIST TDA AS SHRTWV
TROF MOVES ACRS NEW ENGLAND THIS MRNG. RESULT WILL BE SCT-BKN DECK
OF CI MOVG OVR THRU EARLY AFTN...WITH CLRG BY EVE.
H85 TEMPS 16-18C NOTED IN 00Z UPR AIR OBS AT KPBZ...KILN...KDTX
AND KBUF. WITH NWLY H85 FLOW XPCD TDA...XPCG SAME TO BE ADVCTD
INTO FCST AREA. UPR LVL CLDS TO LINGER DURG MRNG AND EARLY AFTN
HRS...SO WILL NOT CARRY MAXIMA QUITE AS AGGRESSIVE AS MEXMOS VALS.
NEVERTHELESS...WARM DAY XPCD...WITH MAXIMA UPR 70S TO LWR 80S.
&&
.SHORT TERM /TONIGHT/...
LGT AND VRB WINDS TO RETURN THIS EVE AS SFC HIPRES DOMINATES. CLRG
SKIES...LGT WINDS AND DRY AIR ASSOCIATED WITH SFC HIPRES SHUD ALLOW
FOR EFFICIENT RADIATIONAL COOLING AND POTENTIAL FOR PATCHY FOG TNGT.
MINIMA IN MID TO UPR 30S TNGT HIGHER TERRAIN PSBL...MID TO UPR 40S
CNTRL ZONES...AND LOW TO MID 50S ERN ZONES...WHERE UPR LVL CLDS TO
LINGER INTO THIS EVE.
WILL NEED TO MONITOR FOR POTENTIAL FOR LOCALIZED FROST WRN ZONES
AS FCST MINIMA CLOSE TO LCL THRESHOLDS FOR ADZY.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
A DEEP WESTERN CONUS TROUGH AND AMPLIFIED EASTERN CONUS RIDGE HAS
DEVELOPED AT 500MB DURING THE PAST 5 DAYS...AS THE NEXT STRONG
DISTURBANCE MOVES OVER THE WESTERN PACIFIC WATERS WITH RIDGING AHEAD
OF THE SYSTEM OVER THE CENTRAL PACIFIC. WATER VAPOR LOOP SHOWS THE
RIDGE DOMINATING THE EASTERN CONUS...WITH A STRONG DISTURBANCE
BEGINNING TO EXIT THE WESTERN CONUS TROUGH OVER THE UPPER MIDWEST.
SUBSTANTIAL DRY AIR ALOFT IS DEVELOPING OVER THE SOUTHWESTERN CONUS
AS THE TROUGH BEGINS TO ELONGATE. ACARS 400-250MB WIND OBSERVATIONS
REVEAL THAT A 100-125KT JET CARVES A WESTERN CONUS TROUGH
/PARTICULARLY ON THE LEADING EDGE OF THE TROUGH/...AND CURVES
ANTICYCLONICALLY FROM THE HUDSON BAY TO THE CANADIAN MARITIMES.
THE LATE EVENING SURFACE MAP FEATURED A 1032MB HIGH PRESSURE
SYSTEM BUILDING ACROSS THE MID ATLANTIC FROM NEW ENGLAND...WITH
THE WARM/STATIONARY BOUNDARY STRETCHING FROM THE WESTERN GREAT
LAKES SOUTH TO THE GULF STATES THEN EAST OFF THE SOUTH CAROLINA
COAST. THE NEXT COLD FRONT WAS CROSSING THE UPPER MIDWEST AND
PLAINS.
12Z GFS ENSEMBLES AND LAST SEVERAL RUNS OF GFS/EUROPEAN MODELS ARE
IN GENERALLY GOOD AGREEMENT THROUGH THE LONG RANGE. HIGH PRESSURE
SURFACE AND ALOFT WEAKEN DURING THE MIDWEEK AS A DISTURBANCE FROM
THE WESTERN CONUS TROUGH FLATTENS THE RIDGE. THIS SHOULD ALLOW A
COLD FRONT TO GRADUALLY PUSH THROUGH THE REGION DURING THE LATE WORK
WEEK. GIVEN THE ZONAL FLOW ALOFT AND MEAGER CONVERGENCE ALONG THE
BOUNDARY...HAVE LEFT SILENT 20 POPS FOR THIS PERIOD.
SURFACE HIGH PRESSURE WILL BUILD SLOWLY INTO THE REGION NEXT
WEEKEND...WITH THE PASSAGE OF AN UPPER TROUGH. COOL BREEZY
CONDITIONS EXPECTED UNDER CLEARING SKIES.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
LGT LOW LVL WINDS AND SCT-BKN CI DECK XPCD THRU THIS EVE WITH
PERSISTENCE OF STG UPR RDG AND SFC HIPRES.
HIGH PRESSURE DOMINATES DURING THE EARLY WORK WEEK...WITH PERHAPS
SPOTTY MVFR SUNRISE FOG AT CLIMATOLOGICALLY FAVORED LOCATIONS. WEAK
FRONTAL BOUNDARY DROPS SLOWLY ACROSS THE REGION DURING THE LATTER
PORTION OF THE WORK WEEK...BRINGING A CHANCE OF RAIN /WITH PRIMARILY
MVFR-VFR CONDITIONS/. PRELIMINARY LOOK TOWARD THE WEEKEND SHOWS A
GOOD CHANCE OF GUSTY NORTHWESTERLY WINDS AS THE PRESSURE GRADIENT
INCREASES ON THE LEADING EDGE OF BUILDING HIGH PRESSURE.
&&
.MARINE...
NO MARINE HAZARDS XPCD THRU TNGT AS LGT LOW LVL WINDS AND DRY WX
PERSIST OWING TO STG UPR RDG AND SFC HIPRES.
HIGH PRESSURE WILL PROVIDE RELATIVELY LIGHT WINDS ACROSS THE WATERS
THROUGH MID WEEK. WINDS EXPECTED TO BECOME A BIT STRONGER FROM THE
NORTHWEST OR NORTH LATE DURING THE WORK WEEK WITH THE PASSAGE OF A
COLD FRONT. PRELIMINARY LOOK TOWARD THE WEEKEND SHOWS A GOOD CHANCE
OF SMALL CRAFT ADVISORY WINDS AS THE PRESSURE GRADIENT INCREASES ON
THE LEADING EDGE OF BUILDING HIGH PRESSURE.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.
&&
$$
KRAMAR/ROGOWSKI
AREA FORECAST DISCUSSION...UPDATED
NWS MARQUETTE MI
742 PM EDT TUE OCT 14 2008
UPDATED AVIATION DISCUSSION FOR 00Z TAF ISSUANCE
.SYNOPSIS... ISSUED AT 342 PM EDT
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW WEST-TO-EAST FAST
NRN BRANCH FLOW ACRS SRN CAN TO THE N OF PERSISTENT SRN BRANCH RDG
OVER THE SE CONUS AND A SRN TROF IN THE DESERT SW. POTENT
SHRTWV/COLD FNT RESPONSIBLE FOR SHRA/WINDS LAST NGT AND MUCH COOLER
WX TDAY ARE NOW HEADING E INTO QUEBEC. IN THEIR WAKE...SHRTWV RDGING
(12HR H3 HGT RISE AT BIS AN IMPRESSIVE 210M)/SFC HI PRES ARE BLDG
TOWARD THE UPR LKS. GUSTY WINDS ARE DIMINISHING WITH APRCH OF THE
RDG AXIS. THE INCOMING AIRMASS IS QUITE DRY PER THE 12Z BIS RAOB...
SO SC OVER THE NRN TIER UNDER LINGERING LLVL THERMAL TROFFING BLO
SUBSIDENCE INVRN ARND H85-9 AS SEEN ON EARLIER RAOBS/TAMDAR SDNGS IS
TENDING TO DSPT WITH THIS INFLUX OF DRIER AIR AND SUBSIDENCE
ASSOCIATED WITH THE RDG. ANOTHER POTENT SHRTWV IS NOTED MOVING ALG
THE US/CNDN BORDER THRU THE NRN BRANCH FLOW...12HR H3 HGT FALL WAS
240M IN ALBERTA. DESPITE LIMITED MSTR IN THE NRN ROCKIES (12Z PWAT
ARND 0.50 INCH)...A FEW LTG STRIKES NOTED WITHIN COMMA TAIL CLD
ASSOCIATED WITH THIS SHRTWV. MSTR PLUME ASSOCIATED WITH SHRTWV IN
THE DESERT SW IS STREAMING AS FAR N AS MN. BUT MOST OF THE MSTR
TOWARD THE NRN END OF THE PLUME IS ALF PER RAOBS TO THE SW...WHICH
SHOW LINGERING LLVL DRY AIR AT OMA/DVN.
&&
.SHORT TERM DISCUSSION (TNGT AND WED)... ISSUED AT 342 PM EDT
MAIN FCST CONCERNS IN THIS PD ARE TEMPS AND PCPN CHCS ASSOCIATED
WITH MSTR STREAMING N AHEAD OF SRN BRANCH TROF.
FOR TNGT...QUICK MOVING SHRTWV RDG/SFC RDG AXIS WL SLIDE TO THE E OF
THE FA THIS EVNG IN FAST NRN BRANCH FLOW. POTENT SHRTWV NOW MOVING
ALG THE US/CNDN BORDER IS PROGGED TO REACH JUST E OF LK WINNIPEG BY
12Z WED...WITH SFC LO/ATTENDANT COLD FNT MOVING TO NW ONTARIO/WRN LK
SUP. MEANWHILE...THE UPR LVL FLOW IS FCST TO BACK SW ENUF IN ADVANCE
OF THIS INCOMING SHRTWV TO DRAW MID/UPR LVL MSTR TO THE SW INTO AT
LEAST THE SE 1/2 TO 2/3 OF THE FA AS SHOWN ON THE 300-310K
ISENTROPIC SFCS (H725-575). SO...EXPECT AN INCRS IN HI/MID CLD...
ESPECIALLY ACRS THE SE COUNTIES. ALTHOUGH THE GFS/NAM BRUSH THE
SCNTRL ZNS FM IMT-MNM WITH LGT PCPN TOWARD 12Z...PREFER THE DRIER
LOCAL WRF-ARW RUN...WHICH KEEPS PCPN S OF GRB THRU 12Z...SINCE THE
H85-925 WINDS ARE FCST TO BACK LESS AND STAY MORE WSW. THIS
DIRECTION WOULD MAINTAIN THE FEED OF LLVL DRY AIR FM THE NRN PLAINS.
ON WED...PREFER THE STRONGER GFS FCST FOR THE INCOMING SHRTWV TROF
CONSIDERING THE INTENSE NATURE OF THIS SYS NOW MOVING INTO THE NRN
PLAINS. RATHER QUICK PROGRESSION OF THIS SYS/VEERING WINDS WL TEND
TO SHUNT THE DEEPER STRN STREAM MSTR TO THE S...BUT WL RETAIN SCHC
POPS ACRS THE FAR SE IN THE MRNG WHERE GFS SHOWS SOME UPR DVGC IN
RRQ OF 120KT H3 JET MAX OVER LK SUP. OTRW...MRNG CLDS WL GIVE WAY TO
CLRG WITH ARRIVAL OF MID LVL DRYING BEFORE COLDER AIR ARRIVES IN
THE AFTN (H85 TEMPS FALLING TOWARD -2C) AND CAUSES SC DVLPMNT
DOWNWIND OF LK SUP IN W FLOW VEERING NW. HI TEMPS WL REACH ONLY THE
LO 50S OVER THE W WITH EARLIER ARRIVAL OF TROF/COLD FNT...BUT MIXING
TO H85 OVER THE SCNTRL ON GFS FCST SDNGS YIELDS HI TEMPS ARND 60.
COORDINATED WITH APX/LOT/GRB/DLH/ENVIRONMENT CAN.
.LONG TERM (WED NGT THRU TUE)...
RELATIVELY QUIET WEATHER IS EXPECTED THROUGHOUT THE EXTENDED
FORECAST PERIOD. AFTER WEDNESDAY/S DRY FRONTAL PASSAGE FAIRLY DRY
AIR FILTER/S INTO THE CWA FROM THE NORTHWEST AS INDICATED BY PWAT/S
PROGGED TO BE LESS THAN 0.50 INCHES. DESPITE DRY AIR...THINK CLOUDS
OFF THE LAKE WILL KEEP TEMPERATURES FROM GETTING TOO COLD. NEXT
OPPORTUNITY FOR PRECIP. IS SUNDAY AHEAD OF A FRONTAL PASSAGE
ASSOCIATED WITH LOW PRESSURE TRACKING ACROSS HUDSON BAY. BEST
FORCING AS INDICATED BY 850-300MB QVECTOR CONVERGENCE REMAINS NORTH
OF LAKE SUPERIOR...THOUGH MOISTURE ACROSS THE U.P. EXTENDS UP TO
15KFT. EXPECT MEAGER RAINFALL AMOUNTS AS BETTER RAINS WILL LIKELY
REMAIN WELL TO THE NORTH WITH BEST FORCING. LOWERED MIN TEMPS FOR
MONDAY NIGHT BEHIND SUNDAY/S FRONT. HIGH PRESSURE LOOKS TO SETTLE IN
ALONG WITH PWAT/S AOA 0.25 INCHES COULD YIELD A COLD NIGHT.
&&
AVIATION (FOR THE 00Z TAF ISSUANCE)...
AREA OF RAIN CURRENTLY STREAKING NE THRU THE PLAINS TOWARD THE
UPPER MISSISSIPPI VALLEY UNDER RIGHT ENTRANCE OF UPPER LEVEL JET
STREAK SHOULDN`T BE AN ISSUE AT KCMX/KSAW AS DRY AIRMASS PER RECENT
REGIONAL TAMDAR SOUNDINGS WORKS TO LIMIT NE PROGRESS. MAIN IMPACT
SHOULD BE A BKN/OVC MID CLOUD DECK. COLD FRONT WILL SWEEP ACROSS
UPPER MI WED...BRINGING ANOTHER ROUND OF GUSTY W WINDS TO KCMX. MVFR
CIGS MAY DEVELOP IN THE WAKE OF THE FRONT AT KCMX AS SUGGESTED BY
MODEL DATA AND PER UPSTREAM OBS BEHIND FRONT IN NW ND/NE MT. AT
KSAW...VFR CONDITIONS SHOULD PREVAIL EVEN AFTER FROPA UNDER
DOWNSLOPING POST FRONTAL WRLY WINDS.
&&
.MARINE (FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)...
EXPECT A HIGH PRESSURE RIDGE TO BRIEFLY BUILD ACROSS THE UPPER GREAT
LAKES TONIGHT. LOW PRESSURE WILL MOVE EAST ACROSS NORTHERN ONTARIO
DURING THE DAY ON WEDNESDAY AND DRAG A COLD FRONT THROUGH THE UPPER
GREAT LAKES. HOISTED A GALE WATCH TO ACCOUNT FOR THE STRENGTH OF
THIS SYS AND FORECAST ARRIVAL OF W TO NW 35 KNOT WINDS WITHIN
DEEPENING MIXED LAYER OVER THE OPEN WATER WED AFTERNOON AND EVENING
DURING ARRIVAL OF COLDER AIR. HIGH PRESSURE WILL BUILD ACROSS THE
GREAT LAKES WEDNESDAY NIGHT...CAUSE ANY GALES TO END...AND REMAIN
STATIONARY OVER THE LAKES INTO SATURDAY. A LOW PRESSURE TROF OF
29.7 INCHES WILL MOVE EASTWARD OUT OF THE NORTHERN PLAINS BY LATE
SATURDAY AND ACROSS THE UPPER GREAT LAKES BY LATE SUNDAY. SW WINDS
UP TO 30 KNOTS ARE POSSIBLE IN ADVANCE OF THIS SYSTEM.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...NONE.
LAKE SUPERIOR...
GALE WATCH WED EVENING THRU LATE WED NIGHT LSZ250-251-267.
GALE WATCH WED AFTN THRU LATE WED NIGHT LSZ248-249-265-266.
GALE WATCH WED AFTN THRU WED EVENING LSZ242>244-263-264.
LAKE MICHIGAN...NONE.
&&
$$
SYNOPSIS/SHORT TERM DISCUSSION...KC
LONG TERM DISCUSSION...PEARSON
AVIATION...ROLFSON
MARINE...KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
342 PM EDT TUE OCT 14 2008
.SYNOPSIS...
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW WEST-TO-EAST FAST
NRN BRANCH FLOW ACRS SRN CAN TO THE N OF PERSISTENT SRN BRANCH RDG
OVER THE SE CONUS AND A SRN TROF IN THE DESERT SW. POTENT
SHRTWV/COLD FNT RESPONSIBLE FOR SHRA/WINDS LAST NGT AND MUCH COOLER
WX TDAY ARE NOW HEADING E INTO QUEBEC. IN THEIR WAKE...SHRTWV RDGING
(12HR H3 HGT RISE AT BIS AN IMPRESSIVE 210M)/SFC HI PRES ARE BLDG
TOWARD THE UPR LKS. GUSTY WINDS ARE DIMINISHING WITH APRCH OF THE
RDG AXIS. THE INCOMING AIRMASS IS QUITE DRY PER THE 12Z BIS RAOB...
SO SC OVER THE NRN TIER UNDER LINGERING LLVL THERMAL TROFFING BLO
SUBSIDENCE INVRN ARND H85-9 AS SEEN ON EARLIER RAOBS/TAMDAR SDNGS IS
TENDING TO DSPT WITH THIS INFLUX OF DRIER AIR AND SUBSIDENCE
ASSOCIATED WITH THE RDG. ANOTHER POTENT SHRTWV IS NOTED MOVING ALG
THE US/CNDN BORDER THRU THE NRN BRANCH FLOW...12HR H3 HGT FALL WAS
240M IN ALBERTA. DESPITE LIMITED MSTR IN THE NRN ROCKIES (12Z PWAT
ARND 0.50 INCH)...A FEW LTG STRIKES NOTED WITHIN COMMA TAIL CLD
ASSOCIATED WITH THIS SHRTWV. MSTR PLUME ASSOCIATED WITH SHRTWV IN
THE DESERT SW IS STREAMING AS FAR N AS MN. BUT MOST OF THE MSTR
TOWARD THE NRN END OF THE PLUME IS ALF PER RAOBS TO THE SW...WHICH
SHOW LINGERING LLVL DRY AIR AT OMA/DVN.
&&
.SHORT TERM DISCUSSION (TNGT AND WED)...
MAIN FCST CONCERNS IN THIS PD ARE TEMPS AND PCPN CHCS ASSOCIATED
WITH MSTR STREAMING N AHEAD OF SRN BRANCH TROF.
FOR TNGT...QUICK MOVING SHRTWV RDG/SFC RDG AXIS WL SLIDE TO THE E OF
THE FA THIS EVNG IN FAST NRN BRANCH FLOW. POTENT SHRTWV NOW MOVING
ALG THE US/CNDN BORDER IS PROGGED TO REACH JUST E OF LK WINNIPEG BY
12Z WED...WITH SFC LO/ATTENDANT COLD FNT MOVING TO NW ONTARIO/WRN LK
SUP. MEANWHILE...THE UPR LVL FLOW IS FCST TO BACK SW ENUF IN ADVANCE
OF THIS INCOMING SHRTWV TO DRAW MID/UPR LVL MSTR TO THE SW INTO AT
LEAST THE SE 1/2 TO 2/3 OF THE FA AS SHOWN ON THE 300-310K
ISENTROPIC SFCS (H725-575). SO...EXPECT AN INCRS IN HI/MID CLD...
ESPECIALLY ACRS THE SE COUNTIES. ALTHOUGH THE GFS/NAM BRUSH THE
SCNTRL ZNS FM IMT-MNM WITH LGT PCPN TOWARD 12Z...PREFER THE DRIER
LOCAL WRF-ARW RUN...WHICH KEEPS PCPN S OF GRB THRU 12Z...SINCE THE
H85-925 WINDS ARE FCST TO BACK LESS AND STAY MORE WSW. THIS
DIRECTION WOULD MAINTAIN THE FEED OF LLVL DRY AIR FM THE NRN PLAINS.
ON WED...PREFER THE STRONGER GFS FCST FOR THE INCOMING SHRTWV TROF
CONSIDERING THE INTENSE NATURE OF THIS SYS NOW MOVING INTO THE NRN
PLAINS. RATHER QUICK PROGRESSION OF THIS SYS/VEERING WINDS WL TEND
TO SHUNT THE DEEPER STRN STREAM MSTR TO THE S...BUT WL RETAIN SCHC
POPS ACRS THE FAR SE IN THE MRNG WHERE GFS SHOWS SOME UPR DVGC IN
RRQ OF 120KT H3 JET MAX OVER LK SUP. OTRW...MRNG CLDS WL GIVE WAY TO
CLRG WITH ARRIVAL OF MID LVL DRYING BEFORE COLDER AIR ARRIVES IN
THE AFTN (H85 TEMPS FALLING TOWARD -2C) AND CAUSES SC DVLPMNT
DOWNWIND OF LK SUP IN W FLOW VEERING NW. HI TEMPS WL REACH ONLY THE
LO 50S OVER THE W WITH EARLIER ARRIVAL OF TROF/COLD FNT...BUT MIXING
TO H85 OVER THE SCNTRL ON GFS FCST SDNGS YIELDS HI TEMPS ARND 60.
COORDINATED WITH APX/LOT/GRB/DLH/ENVIRONMENT CAN.
...LONG TERM (WED NGT THRU TUE)...
RELATIVELY QUIET WEATHER IS EXPECTED THROUGHOUT THE EXTENDED
FORECAST PERIOD. AFTER WEDNESDAY/S DRY FRONTAL PASSAGE FAIRLY DRY
AIR FILTER/S INTO THE CWA FROM THE NORTHWEST AS INDICATED BY PWAT/S
PROGGED TO BE LESS THAN 0.50 INCHES. DESPITE DRY AIR...THINK CLOUDS
OFF THE LAKE WILL KEEP TEMPERATURES FROM GETTING TOO COLD. NEXT
OPPORTUNITY FOR PRECIP. IS SUNDAY AHEAD OF A FRONTAL PASSAGE
ASSOCIATED WITH LOW PRESSURE TRACKING ACROSS HUDSON BAY. BEST
FORCING AS INDICATED BY 850-300MB QVECTOR CONVERGENCE REMAINS NORTH
OF LAKE SUPERIOR...THOUGH MOISTURE ACROSS THE U.P. EXTENDS UP TO
15KFT. EXPECT MEAGER RAINFALL AMOUNTS AS BETTER RAINS WILL LIKELY
REMAIN WELL TO THE NORTH WITH BEST FORCING. LOWERED MIN TEMPS FOR
MONDAY NIGHT BEHIND SUNDAY/S FRONT. HIGH PRESSURE LOOKS TO SETTLE IN
ALONG WITH PWAT/S AOA 0.25 INCHES COULD YIELD A COLD NIGHT.
&&
AVIATION (FOR THE 18Z TAF ISSUANCE)...
EXPECT VFR CONDITIONS TO PREDOMINATE THIS FCST PD WITH ARRIVAL OF
DRY AIRMASS TO THE W AS SHOWN ON THE 12Z BIS RAOB. OTRW...GUSTY
WINDS WL DIMINISH BY LATE TDAY WITH ARRIVAL OF HI PRES RDG. BUT SW
FLOW WL THEN PICK UP WED MRNG AS THE RDG PUSHES TO THE E AND A STRG
DISTURBANCE/LO PRES TROF APRCHS FM THE W.
&&
.MARINE (FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)...
EXPECT A HIGH PRESSURE RIDGE TO BRIEFLY BUILD ACROSS THE UPPER GREAT
LAKES TONIGHT. LOW PRESSURE WILL MOVE EAST ACROSS NORTHERN ONTARIO
DURING THE DAY ON WEDNESDAY AND DRAG A COLD FRONT THROUGH THE UPPER
GREAT LAKES. HOISTED A GALE WATCH TO ACCOUNT FOR THE STRENGTH OF
THIS SYS AND FORECAST ARRIVAL OF W TO NW 35 KNOT WINDS WITHIN
DEEPENING MIXED LAYER OVER THE OPEN WATER WED AFTERNOON AND EVENING
DURING ARRIVAL OF COLDER AIR. HIGH PRESSURE WILL BUILD ACROSS THE
GREAT LAKES WEDNESDAY NIGHT...CAUSE ANY GALES TO END...AND REMAIN
STATIONARY OVER THE LAKES INTO SATURDAY. A LOW PRESSURE TROF OF
29.7 INCHES WILL MOVE EASTWARD OUT OF THE NORTHERN PLAINS BY LATE
SATURDAY AND ACROSS THE UPPER GREAT LAKES BY LATE SUNDAY. SW WINDS
UP TO 30 KNOTS ARE POSSIBLE IN ADVANCE OF THIS SYSTEM.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...NONE.
LAKE SUPERIOR...
GALE WATCH FROM WEDNESDAY EVENING THROUGH LATE WEDNESDAY NIGHT
FOR LSZ250-251-267.
GALE WATCH FROM WEDNESDAY AFTERNOON THROUGH LATE WEDNESDAY NIGHT
FOR LSZ248-249-265-266.
GALE WATCH FROM WEDNESDAY AFTERNOON THROUGH WEDNESDAY EVENING
FOR LSZ242>244-263-264.
LAKE MICHIGAN...NONE.
&&
$$
SYNOPSIS/SHORT TERM DISCUSSION...KC
LONG TERM DISCUSSION...PEARSON
AVIATION...KC
MARINE...KC
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
334 PM CDT TUE OCT 14 2008
.SHORT TERM...TONIGHT AND WEDNESDAY. THE NORTHERN EXTENT OF
MEASUREABLE PRECIPITATION FROM THE WEAK SURFACE LOW MOVING
NORTHEAST FROM OKLAHOMA IS THE MAIN CONCERN FOR THIS FORECAST.
AIR IS CURRENTLY VERY DRY OVER OUR FORECAST AREA. IN FACT IT WAS
QUITE DRY ALL THE WAY SOUTH TO WATERLOO AND DUBUQUE AT MIDDAY. A
TAMDAR SOUNDING FROM PEORIA SHOWS SOME MOISTENING AROUND 800 MB.
SO PRECIPITATION WILL TAKE SOME TIME TO GET UP HERE. JUST
INCLUDING A SMALL CHANCE OF RAIN IN THE FAR SOUTHWEST COUNTIES
AFTER 09Z TONIGHT. DECENT LOW LEVEL WARM ADVECTION IN THE
SOUTHEAST THIRD OF THE FORECAST AREA FORECAST BETWEEN 12Z AND 18Z
WEDNESDAY...SO GOING WITH 30 TO 60 POPS IN THAT AREA WITH JUST A
SLIGHT CHANCE IN THE FAR NORTH. RAINFALL AMOUNTS SHOULD BE LIGHT.
.LONG TERM...WEDNESDAY NIGHT THROUGH NEXT TUESDAY.
NO MAJOR CHANGES TO PREVIOUS FORECAST AS ZONAL FLOW BECOMES
SOMEWHAT MORE AMPLIFIED WITH DEEPENING TROUGH OVER THE EASTERN
CONUS BY SATURDAY.
WEAK FRONTAL SYSTEM FORECAST TO EXIT THE STATE EARLY WEDNESDAY
EVENING. LATEST SREF TRENDS SUGGEST FRONT MAY BE A BIT SLOWER TO
EXIT THE STATE. DECIDED TO HANG ONTO LOW CHANCE POPS FOR FOX
VALLEY/EASTERN WISCONSIN INTO EARLY WEDNESDAY EVENING.
SURFACE HI PRESSURE THEN BUILDS ITNO THE WESTERN GREAT LAKES FOR
THE REMAINDER OF THE WEEK. APPEARS LATEST MODEL RUNS HAVE BACKED
OFF ON OVERALL FORCING SIGNAL ASSOCIATED WITH WEAK UPPER-LEVEL
DISTURBANCE MOVING SOUTHEAST ACROSS THE UPPER MIDWEST. DEEP
MOISTURE ALSO APPEARS RATHER LIMITED WITH GULF MOISTURE STILL
ESSENTIALLY NON-EXISTANT. OPTED TO REMOVE MENTION OF PRECIPITATION
FOR THURSDAY NIGHT AND CARRY ONLY SLIGHT CHANCE POPS FOR SOUTHERN
HALF OF FORECAST AREA FOR FRIDAY. WOULD NOT BE SURPRISED TO SEE
PRECIP REMOVED ENTIRELY FOR FRIDAY ASSUMING SUBSEQUENT MODELS
FORECASTS CONTINUE PAULTRY FORCING SIGNAL.
DESPITE SOME DIFFERENCES IN MAGNITUDE AND TIMING OF NEXT MID-LEVEL
SHORTWAVE TO TRAVERSE THE US/CANADA BORDER...MEDIUM RANGE MODELS
SURPRISING SIMILAR ON POSITION OF SURFACE COLD FRONT FORECAST NEAR
THE WISCONSIN/MINNESOTA BORDER BY 12Z SUNDAY. CONTINUED CHANCE
POPS FOR SUNDAY AS FRONT MOVES ACROSS THE STATE.
&&
.AVIATION...VFR EXPECTED THROUGH 09Z TONIGHT...THEN SOME MVFR CIGS
AND VSBYS DUE TO RAIN POSSIBLE MAINLY SOUTH OF A WAUSAU TO GREEN
BAY LINE BETWEEN 09Z AND 18Z WEDNESDAY. THE MVFR CONDITIONS DEPEND ON US
GETTING SOME RAIN. IF THE RAIN DOES NOT MATERIALIZE IT WILL LIKELY
STAY VFR.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
RDM/ESB
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