AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
230 PM PDT WED OCT 15 2008
.SYNOPSIS...HIGH PRESSURE ALOFT AND WEAK OFFSHORE FLOW WILL CONTINUE
WARM DAYS WEST OF THE MOUNTAINS THROUGH FRIDAY. UPPER LEVEL LOW
PRESSURE WILL BRING MORE CLOUDS AND COOLING THIS WEEKEND.
&&
.DISCUSSION...FOR SOUTHWEST CALIFORNIA INCLUDING SAN DIEGO...
ORANGE...SOUTHWEST SAN BERNARDINO AND WEST RIVERSIDE COUNTIES.
.SHORT TERM (TODAY-SAT)...SKIES WERE CLEAR EXCEPT FOR A FEW HIGH
CLOUDS. EARLY AFTERNOON ACARS SOUNDINGS INDICATED A NEAR SURFACE
BASED INVERSION WITH NE WINDS TO ABOUT 15 KTS IN THE LOW LEVELS AND
W TO SW WINDS ALOFT. OFFSHORE GRADIENTS WITH ABOUT -8 MB SAN-TPH.
A WEAK UPPER LOW WILL MEANDER SW OF SAN DIEGO AS HIGH PRESSURE
BUILDS ALOFT INTO FRI. THIS WILL MAINTAIN CLEAR SKIES EXCEPT FOR
A FEW HIGH CLOUDS AT TIMES. THE LOW WILL GET PICKED UP BY A TROUGH
IN THE NE PAC WITH A VORT MAX SKIRTING PAST JUST TO OUR W AND N ON
SAT. THE WEAKENING OFFSHORE FLOW AND HIGH ALOFT WILL CONTINUE HOT
AND DRY DAYS INLAND THROUGH FRI WITH MAX TEMPS IN THE 90S IN MOST
INLAND VALLEYS. THERE WILL STILL BE LOCAL GUSTY OFFSHORE WINDS BUT
THEY WILL GENERALLY BE DECREASING IN STRENGTH AND WILL REMAIN BELOW
ADVISORY STRENGTH. CLEAR AND DRY NIGHTS WILL ALLOW EXCELLENT
RADIATIONAL COOLING IN AREAS PROTECTED FROM THE WINDS. AREAS WITH
SOME WINDS AND MIXING SUCH AS THE LOWER FOOTHILL LOCATIONS WILL STAY
WARMER EACH NIGHT. PATCHY STRATUS COULD RETURN TO THE BEACHES AS
EARLY AS FRIDAY AFTERNOON OR EVENING. THIS SHOULD BRING A LITTLE
COOLING TO THE BEACHES FRIDAY AFTERNOON. A SHALLOW MARINE LAYER WILL
DEVELOP BY SAT MORNING. MAX TEMPS WILL DROP ABOUT 10-15 DEGREES IN
MOST AREAS W OF THE MOUNTAINS SAT WITH LOWERING HEIGHTS AND STRONGER
ONSHORE GLOW. IF THE UPPER LOW TO OUR SW PICKS UP MORE MOISTURE THEN
THERE COULD EVEN BE A FEW LIGHT SHOWERS LATE SAT...MAINLY IN THE NRN
AREAS. WILL INDICATE SOME LOW LEVEL POPS BUT PROBABILITIES TOO LOW
TO INCLUDE IN THE ZONES AT THIS TIME.
LOCAL CRITICAL FIRE WEATHER CONDITIONS WILL CONTINUE INTO FRI IN THE
INLAND VALLEYS AND MOUNTAINS DUE TO LOW HUMIDITIES. SEE THE FIRE
WEATHER DISCUSSION BELOW FOR DETAILS.
&&
.LONG TERM (SUN-WED)...THE TROUGH WILL MOVE THROUGH SUN WITH FLAT
FLOW OR WEAK RIDGING MON. ANOTHER TROUGH SHOULD MOVE PAST TO THE N
TUE. WHILE THE MARINE LAYER WILL DEEPEN...IT SHOULD REMAIN CONFINED
TO THE COASTAL AREAS AND WRN SAN DIEGO INLAND VALLEYS. OFFSHORE FLOW
COULD DEVELOP AFTER THE TROUGH MOVES THROUGH TOWARD THE MIDDLE OF
NEXT WEEK...BUT THE STRENGTH IS UNCERTAIN.
&&
.AVIATION...
152300Z...CLEAR. WEAK LOCALLY MODERATE OFFSHORE FLOW THROUGH
THURSDAY...BECOMING WEST TO NORTHWEST ONSHORE FLOW DURING THE
AFTERNOON. LIGHT TO MODERATE UP AND DOWNDRAFTS IN THE MORNING
NEAR THE MOUNTAINS.
&&
.FIRE WEATHER...
THIS AFTERNOON...WIND SPEEDS HAVE DECREASED SIGNIFICANTLY IN ALL
AREAS WITH THE WIND PRONE AREAS REPORTING GUSTS OF 25 TO 35 MPH.
WEAKER OFFSHORE WINDS WILL CONTINUE INTO FRIDAY...MAINLY DURING THE
MORNINGS FOR SOUTHERN AREAS FAVORED FOR EASTERLY OFFSHORE FLOW. HIGH
PRESSURE ALOFT WILL BRING WARMER DAYTIME TEMPERATURES ABOVE SEASONAL
AVERAGES THROUGH FRIDAY. COMBINED WITH A VERY DRY ATMOSPHERE...THERE
WILL BE SEVERAL HOURS OF RELATIVE HUMIDITIES BELOW 10 PERCENT WITH
LITTLE OVERNIGHT RECOVERY FOR SOME INLAND AREAS THROUGH FRIDAY. IN
THE COASTAL AREAS...A WEAK AFTERNOON SEA BREEZE COULD KEEP
HUMIDITIES ABOVE CRITICAL LEVELS. FOR THE WEEKEND...A TROUGH OF LOW
PRESSURE MOVING INLAND THROUGH SOUTHERN CALIFORNIA WILL BRING
COOLING AND HIGHER HUMIDITIES.
A RED FLAG WARNING IS CURRENTLY IN EFFECT FOR MOST OF EXTREME
SOUTHWEST CALIFORNIA...EXCLUDING THE DESERTS...UNTIL FRIDAY NIGHT
DUE TO LONG DURATION LOW RELATIVE HUMIDITIES CONTINUING THROUGH
FRIDAY ALTHOUGH THE WINDS WILL BE WEAKER.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...
CA...RED FLAG WARNING FOR THE MOUNTAINS...INLAND VALLEYS AND ORANGE
COUNTY COASTAL AREAS UNTIL 10 PM TONIGHT AND CONTINUING FOR THE
MOUNTAINS AND INLAND VALLEYS UNTIL 10 PM FRI.
&&
$$
PUBLIC...ATKIN
AVIATION...SMALL
FIRE WEATHER...PG
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
926 PM EDT WED OCT 15 2008
.SYNOPSIS...
WEAK HIGH PRESSURE ACROSS THE AREA THIS EVENING WILL MOVE OFF TO
THE EAST OVERNIGHT. LOW PRESSURE WILL MOVE ACROSS THE GREAT LAKES
TONIGHT AND THEN ACROSS NEW ENGLAND THURSDAY. AN ATTACHED COLD
FRONT WILL CROSS OUR AREA LATE THURSDAY AND THURSDAY EVENING.
COOLER AIR AND HIGH PRESSURE WILL FOLLOW FOR FRIDAY AND THE
WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
THERE IS AN APPROACHING WEAK, STABLE SHORT WAVE THAT SHOWS UP ON
WATER VAPOR IMAGERY THIS EVENING AND THAT THE NAM DEPICTS. THERE
ALSO IS WEAK INSTABILITY THAT IS SHOWING UP IN THE MOST UNSTABLE
CAPE FIELDS AND THAT IS REFLECTED IN LOW POSITIVE LI VALUES IN THE
MSAS FIELDS, AND THERE IS WEAK ISENTROPIC LIFT. THESE FACTORS,
AGAIN, ARE WEAK, AND WORKING AGAINST THEM ARE RATHER DRY ACARS
SOUNDINGS. MOREOVER, THE ISOLATED ACTIVITY TO OUR WEST THAT HAS
DEVELOPED IN RESPONSE TO THE ABOVE FACTORS IS MOVING DOWNSLOPE AND
HAS BEEN DISSIPATING SO FAR THIS EVENING. TOYED WITH THE IDEA OF
SLIGHT CHANCE POPS, BUT DO NOT THINK WE`LL SEE 15 PERCENT COVERAGE
WITH ANYTHING THAT MIGHT MAKE IT INTO OUR AREA. WE THEREFORE
MAINTAIN THE DRY FORECAST FOR TONIGHT.
SOME TEMPERATURES AROUND THE AREA WERE APPROACHING FORECAST MINS,
BUT WITH CLOUDS APPROACHING WE MADE ONLY MODEST CHANGES.
PATCHY LIGHT FOG IS POSSIBLE BEFORE THE CLOUDS THICKEN TONIGHT,
BUT IT IS NOT EXPECTED TO BE OF SUFFICIENT COVERAGE OR INTENSITY
TO INCLUDE IN THE PUBLIC FORECASTS.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
THE SHORT TERM MODELS IN GOOD AGREEMENT WITH THE SYNOPTIC SYSTEMS
AFFECTING OUR WEATHER IN THE SHORT TERM. A LOW PRESSURE SYSTEM
WILL TRACK ACROSS NEW ENGLAND THURSDAY AND THEN OFF THE COAST
THURSDAY NIGHT. A COLD FRONT WILL MOVE ACROSS THE LAND AREAS
DURING THE AFTERNOON AND THEN ACROSS THE WATERS DURING THE
EVENING. THE FRONT WILL BE PRECEDED AND ACCOMPANIED BY SCATTERED
SHOWERS. INSTABILITY ON THE LATEST SOUNDINGS LOOKS A TAD MORE
ROBUST, AND WE`LL LEAVE IT TO THE NEXT FORECASTER TO DECIDE
WHETHER ISOLATED THUNDER WILL BE INCLUDED. RAIN CHANCES DECREASE
FROM WEST TO EAST THURSDAY NIGHT AND SKIES WILL BECOME PARTLY
CLOUDY OVERNIGHT. LOWS WILL DROP INTO THE 40S IN MANY AREAS.
HIGH PRESSURE WILL BE TO THE WEST FRIDAY AND A GOOD NORTHERLY FLOW
OF COOL AIR WILL BE ACROSS THE AREA. HIGHS ON FRIDAY WILL ACTUALLY
BE CLOSE TO NORMAL FOR MID OCTOBER, BUT SINCE TEMPERATURES HAVE
BEEN SO WARM RECENTLY, IT MAY TAKE A BIT OF GETTING USED TO.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
NOW THAT THE EXTENDED MODELS ARE MORE PROGRESSIVE WITH THE UPPER
TROUGH ACROSS THE REGION THIS WEEKEND, THE SURFACE LOW THAT WILL
DEVELOP OFF THE CAROLINA COAST ON SATURDAY WILL HARMLESSLY PASS OFF
INTO THE ATLANTIC. THERE MAY BE SOME ENHANCED WINDS AND WAVES
AFFECTING THE COASTAL AREAS HOWEVER. WE ARE LOOKING AT A FAIR
WEATHER WEEKEND WITH TEMPERATURES IN THE BELOW NORMAL RANGE (FOR A
CHANGE). HIGHS ON SATURDAY WILL BE IN THE MID TO UPPER 50S IN MOST
AREAS WITH PERHAPS A FEW LOW 60S. A COOL MORNING SUNDAY MAY BRING
MORE FROST IN THE LEHIGH VALLEY OR PERHAPS INTO THE PINELANDS OF NJ.
THE HIGH THAT WILL BRING THE FAIR WEATHER THIS WEEKEND WILL PASS OFF
THE COAST MONDAY AND A REINFORCING SURGE OF COLD AIR BEHIND A
SURFACE COLD FRONT WILL ARRIVE MONDAY NIGHT. THE UPPER TROUGH WILL
BE SHARP AND THERE IS A DECENT AMOUNT OF UPPER ENERGY PROGGED BY THE
12Z GFS AND OTHER MODELS, LOW LEVEL MOISTURE LOOKS LIMITED, SO I
WILL JUST KEEP THE SLIGHT CHC TO CHC POPS FOR MONDAY NIGHT.
ANOTHER HUGE HIGH WILL BUILD IN TUESDAY AND LAST THROUGH THE
REMAINDER OF THE EXTENDED PERIOD. MORE FAIR WEATHER AND SEASONABLY
COOL TEMPERATURES WILL ACCOMPANY THE HIGH.
&&
.AVIATION /01Z THURSDAY THROUGH MONDAY/...
AT 00Z THURSDAY CLOUDS WERE BEGINNING TO APPROACH THE AREA FROM THE
WEST, BUT VFR CONDITIONS WILL MOSTLY RULE THE TAF SITES THROUGH THIS
24 HOUR FORECAST. A DAMPING VORTICITY LOBE WAS SENDING SOME
WEAKENING SHOWERS EASTWARD FROM CENTRAL PENNSYLVANIA, BUT THESE WILL
BE IGNORED AS THEY DIMINISH AND MOVE INTO DRIER AIR. OTHERWISE, MID
CLOUDS ARE FORECAST TO INVADE FROM THE WEST DURING THIS EVENING, AND
A FAIRLY HIGH OVERCAST SHOULD DEVELOP IN THE EARLY OVERNIGHT PERIOD,
POSSIBLY WITH SOME STRATOCUMULUS FURTHER NORTH. THIS ACTION WILL
LIKELY BE A BIT LATER IN THE OVERNIGHT PERIOD DOWN SOUTH FOR KMIV
AND KACY. MOS GUIDANCE TRIED TO SHOW SOME MARGINAL VFR VISIBILITIES
AT THE RURAL TAF SITES LATE TONIGHT AND AROUND SUNRISE THURSDAY, AND
THIS WAS ACCEPTED FOR KABE, KRDG, AND KMIV, WITH A TEMPO GROUP FOR A
FEW OTHER SITES. KOXB DISPLAYED A HINT OF 6 HUNDRED FOOT CLOUDS
EARLIER, AND WITH A LIGHT SOUTH-SOUTHEAST FLOW ESPECIALLY OVER THE
SOUTHEASTERN TAF SITES, A FEW006 GROUP WAS CARRIED FOR KACY, KMIV,
AND KILG LATER ON TONIGHT. HOPEFULLY, THIS WILL NOT TRANSLATE INTO
IFR CEILINGS, HOWEVER BUFKIT DID SHOW SATURATION AT THE LOWEST
LEVELS LATER TONIGHT AND UNTIL AN HOUR OR SO AFTER SUNRISE EARLY
THURSDAY MORNING. OTHERWISE, CEILINGS SHOULD BE LOWERING TO BROKEN
TO OVERCAST STRATOCUMULUS AS THE MAIN FORCING ARRIVES THURSDAY
MORNING. A TEMPO GROUP WAS CARRIED FOR SHOWERS NORTH, OTHERWISE A
SHOWER VICINITY REMARK WAS USED ELSEWHERE, EVEN DELAYING THAT UNTIL
THE AFTERNOON FOR THE SOUTHEASTERN TAF SITES. COLD FRONTAL PASSAGE
LOOKS TO BE AROUND MIDDAY THURSDAY OR EARLY THURSDAY AFTERNOON, A
LITTLE EARLIER OR LATER DEPENDING ON ONE`S MODEL OF CHOICE, BUT
WINDS SHOULD VEER TO WEST BY MIDDAY AND THEN TO NORTHWEST BY DAY`S
END. THERE COULD BE SOME BREAKS IN THE CLOUDS LATE, IF THE NAM IS
ACCEPTED.
FOR THE OUTLOOK, HIGH PRESSURE WILL BUILD OVER THE REGION FRIDAY
INTO EARLY NEXT WEEK, WITH VFR WEATHER EXPECTED TO PREVAIL.
&&
.MARINE...
WINDS AND SEAS CONTINUE TO BE PRETTY GOOD FOR FALL, WITH CONDITIONS
WELL BELOW SMALL CRAFT ADVISORY CRITERIA OVERNIGHT AND THURSDAY.
SEAS WERE 3 FEET AT BUOY 44009 AND LESS...1 OR 2 FEET...ACROSS LOWER
DELAWARE BAY. WINDS WERE LIGHT SOUTHERLY. SIMILAR CONDITIONS WILL
CONTINUE INTO THURSDAY, THEN A COLD FRONT WILL MOVE THROUGH FROM THE
WEST AND SHOULD REACH THE COAST BY EARLY THURSDAY AFTERNOON. COOLER
AIR ALOFT WILL EXTEND TO THE SEA SURFACE THURSDAY EVENING AND WE MAY
HAVE A FEW GUSTS TO 20 OR EVEN 25 KT AROUND MIDNIGHT THURSDAY NIGHT
FOR A COUPLE OF HOURS. FOLLOWING THE FRONT, HIGH PRESSURE WILL COVER
THE COASTAL WATERS FOR SEVERAL DAYS. HOWEVER, AFTER THE FRONT PASSES
TO OUR SOUTH, IT WILL SLOW DOWN AND A WEAK WAVE WILL FORM ON THE
FRONT AND TRACK TO THE NORTHEAST. THE LOW WILL REMAIN WELL OFFSHORE,
BUT THE GRADIENT BETWEEN IT AND HIGH PRESSURE WILL GIVE US NORTHEAST
WINDS AND BUILDING SEAS. EXPECT TO SEE SEAS BEGIN TO REACH 5 FEET
LATE FRIDAY NIGHT, AND A SMALL CRAFT ADVISORY WILL PROBABLY BE
NEEDED BY THEN. HIGH PRESSURE WILL NUDGE THE LOW FARTHER OFFSHORE,
AND IMPROVING CONDITIONS ARE EXPECTED AT LEAST FOR SUNDAY INTO EARLY
NEXT WEEK.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...O`HARA
NEAR TERM...DELISI/O`HARA
SHORT TERM...DELISI/O`HARA
LONG TERM...O`HARA
AVIATION.../
MARINE...EBERWINE/
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1130 AM 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 (12Z TAFS)...
VFR CONDITIONS WILL CONTINUE THROUGH THE FORECAST PERIOD. A COOL
FRONT WILL DROP INTO SOUTHERN ILLINOIS AND INDIANA TONIGHT. A
STRATO-CU DECK FROM 5-8K FT WILL BE NOTED FOR MUCH OF THE TIME.
&&
.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
1028 AM EDT TUE OCT 14 2008
.SYNOPSIS...
HIGH PRESSURE ALOFT WILL DOMINATE THE WEATHER THROUGH WEDNESDAY
NIGHT...WITH DRY AND WARM CONDITIONS EXPECTED. AN APPROACHING
COLD FRONT AND STRONG UPPER DISTURBANCE MOVE THROUGH THURSDAY.
CONSEQUENTLY...RAIN CHANCES INCREASE LATE IN THE WEEK...WITH COOL
AND BREEZY CONDITIONS EXPECTED FOR THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A CPL OF STUBBORN PATCHES OF FOG ARND MRB/CBE...OTRW JUST WISPY CI
IN MTRS AND ON STLT. 12Z LWX RAOB DEPICTS THIS NICELY...W/ MSTR
EVIDENT AOA H4. SNDGS ALSO DEPICT STEEP LLVL INVSN. FULL SUN TEMPS
ARND RGN MID 80S TO ARND 90. IF ONLY IT WERENT MID OCT!
THERE WL BE TWO FACTORS TO CONSIDER FOR TDA/S MAXT FCST. FIRST...
UPR RDG STARTING TO BREAK DWN IN RESPONSE TO S/WV ENERGY TRACKING
ACRS NRN CONUS. THAT ENERGY WL LEAD TO A BIT OF CLDCVR TAFTN...
MOSTLY MID-HIGH DECK. BUT...TDA/S SNDG WARMER THAN YDA BLO H8. WL
USE YDA OBSVD AS A GUIDE. THINK GOING FCST ACTUALLY A GOOD TARGET.
ANY CLDCVR THAT THE NRN STREAM VORT WL PROVIDE STILL SVRL HRS OFF.
SO...HV REVAMPED SKYCOVER GRIDS A BIT. WNDS WERE TWEAKED TO MATCH
GOING CONDS TOO. IN ALL...CHGS WERENT SGFNT ENUF TO WARRANT UPDT
OF TXT PRODUCTS. WL BE SENDING GRIDS/DIGITAL PRODUCTS...BUT WL
WAIT TIL MRNG FOG GONE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM WEDNESDAY/...
WITH DEPARTURE OF UPR WAVE...CDFNT XPCD TO BCM QUASISTATIONARY
TNGT. MSTR ALONG THIS BNDRY SHUD BE SUFFICIENT FOR LOW CLD DVLPMT
ACRS SRN PA...WHICH WILL ADVCT INTO FCST AREA WITH WNWLY LOW LVL
FLOW. HAVE CONTD MOCLDY SKIES TNGT NRN ZONES.
INCRG CVRG OF LWR CLDS TNGT WILL PRECLUDE EFFICIENT RADIATIONAL
COOLING...KEEPING MINIMA SLGTLY ABV VALUES SEEN THIS MRNG AND
SUPPRESSING FOG ISSUES.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
500MB HEIGHT/ANOMALY PATTERN DURING THE PAST 5 DAYS SHOWS A
WEAKENING WESTERN CONUS TROUGH...WITH AN EASTERN CONUS RIDGE IN
PLACE. MEANWHILE...A JET STRENGTHENS OVER THE NORTHERN PACIFIC.
WATER VAPOR LOOP SHOWS A VIGOROUS SHORT WAVE TROUGH NEARING THE
NORTHERN GREAT LAKES FROM THE WEST...AS THE WESTERN TROUGH
ELONGATES...LEAVING AN UPPER LOW TO MEANDER EAST OVER THE FOUR
CORNERS REGION. RIDGING IS IN PLACE OVER THE EASTERN CONUS...
ALBEIT FLATTENING OVER THE GREAT LAKES AS THE DISTURBANCE
APPROACHES. ACARS 400-250MB WIND OBSERVATIONS REVEAL A 100-145KT
JET FROM THE UPPER LOW NEAR THE FOUR CORNERS REGION...CURVING
ANTICYCLONICALLY FROM THE HUDSON BAY OVER THE NEW ENGLAND COAST.
THE LATE EVENING SURFACE MAP FEATURED A WEAKENING 1028MB HIGH
PRESSURE SYSTEM ACROSS THE MID ATLANTIC...WITH A BACKDOOR COLD
FRONT SLIDING SOUTHWEST INTO NEW YORK. ANOTHER COLD FRONT WAS
NEARING THE MISSISSIPPI RIVER.
12Z GFS ENSEMBLES AND LAST SEVERAL RUNS OF GFS/EUROPEAN/CANADIAN
MODELS ARE IN GENERALLY GOOD AGREEMENT THROUGH THE LONG RANGE. HIGH
PRESSURE SURFACE AND ALOFT WEAKEN DURING THE MIDWEEK AS A
DISTURBANCE FROM THE NORTH CENTRAL CONUS 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...ALTHOUGH CANT RULE OUT A LIGHT QPF EVENT.
GUIDANCE BEGINS TO DIVERGE HEADING INTO THE WEEKEND WITH THE
STRENGTH AND TIMING OF THE NEXT TROUGH APPROACHING FROM THE
PACIFIC NORTHWEST. LAST 2 RUNS OF THE EUROPEAN HAVE THE STRONGEST
SURFACE REFLECTION...WHICH SUGGESTS THE POTENTIAL FOR RAIN
DEVELOPING FRIDAY INTO SATURDAY. GFS/CANADIAN ARE WEAKER UNTIL THE
SYSTEM DEVELOPS ACROSS THE WESTERN ATLANTIC...WHICH CUTS DOWN
PRECIPITATION CHANCES CONSIDERABLY. HAVE INCREASED POPS PARTICULARLY
ACROSS THE SOUTHERN ZONES...BUT WILL HOLD OFF ON FURTHER INCREASES
UNTIL GREATER GUIDANCE CONSISTENCY CAN BE ESTABLISHED.
SURFACE HIGH PRESSURE WILL BUILD SLOWLY INTO THE REGION DURING
NEXT WEEKEND WITH THE PASSAGE OF AN UPPER TROUGH. COOL BREEZY
CONDITIONS EXPECTED UNDER CLEARING SKIES.
&&
.AVIATION /14Z TUESDAY THROUGH SATURDAY/...
PATCHY FOG STILL IMPACTING MRB...W/ MAINLY VSBYS FLUCTUATING BTWN
MVFR AND LIFR. OCT CLIMO SUGGESTS FOG SHUD BE GONE BY 14-15 UTC...
AND WL BE GOING THAT RTE. VFR CONDS ELSW ATTM.
GENLY UPR LVL CLDS XPCD REST OF TDA AS LGT SWLY WINDS DVLP AMID
SFC TROF. WITH MSTR ADVCTN AT 5-7KFT TNGT...WILL CARRY SCT-BKN
DECK AT THIS LVL AFTER 15/00Z.
WEAKENING HIGH PRESSURE CONTINUES INTO THE MID WEEK...WITH
PERHAPS SPOTTY FOG AT CLIMATOLOGICALLY FAVORED LOCATIONS. WEAK
FRONTAL BOUNDARY DROPS SLOWLY ACROSS THE REGION DURING THE LATTER
PORTION OF THE WORK WEEK INTO SATURDAY...BRINGING A CHANCE OF RAIN
/WITH PRIMARILY MVFR-VFR CONDITIONS/. PRELIMINARY LOOK TOWARD THE
WEEKEND SHOWS A GOOD CHANCE OF GUSTY NORTHWESTERLY WINDS AS COOL HIGH
PRESSURE BUILDS INTO THE REGION LATE SATURDAY AND SUNDAY.
&&
.MARINE...
LGT MAINLY SLY WINDS TDA AND TNGT WITH SFC TROF IN VCTY. NO MARINE
HAZARDS XPCD THRU TNGT.
WEAKENING 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 IN THE WORK WEEK WITH THE PASSAGE
OF A COLD FRONT. IT IS UNCERTAIN AT THIS TIME WHETHER DEVELOPING
LOW PRESSURE BRINGS RAIN TO THE REGION HEADING INTO THE WEEKEND.
THERE IS A GOOD CHANCE OF SMALL CRAFT ADVISORY WINDS AS COOL HIGH
PRESSURE BUILDS SLOWLY INTO THE REGION THIS WEEKEND.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KRAMAR
NEAR TERM...HTS
SHORT TERM...KRAMAR
LONG TERM...ROGOWSKI
AVIATION...HTS/KRAMAR/ROGOWSKI
MARINE...HTS/KRAMAR/ROGOWSKI
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
401 AM EDT TUE OCT 14 2008
.SYNOPSIS...
HIGH PRESSURE ALOFT WILL DOMINATE THE WEATHER THROUGH WEDNESDAY
NIGHT...WITH DRY AND WARM CONDITIONS EXPECTED. AN APPROACHING
COLD FRONT AND STRONG UPPER DISTURBANCE MOVE THROUGH THURSDAY.
CONSEQUENTLY...RAIN CHANCES INCREASE LATE IN THE WEEK...WITH COOL
AND BREEZY CONDITIONS EXPECTED FOR THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
QUICK MOVG SHRTWV TROF OVER NRN PLNS THIS MRNG WILL BE DIVERTED N
OF FCST AREA BY STG UPR RDG OVER SERN CONUS. NWLY FLOW ALOFT TO
PERSIST FOR MID ATLC...WITH WK SFC TROF TO DVLP ACRS FCST AREA
TDA AS WKNG SFC HIPRES ERODES. LGT SWLY WINDS ARE XPCD...WITH AN EWD
SHIFT OF SFC TROF AXIS THIS AFTN...YIELDING WIND SHIFT TO WLY/NWLY
ACRS WRN HALF.
APPEARS WK CNVCTN MAY DVLP ALONG CDFNT FM CNTRL NY TO OH WITH
PASSAGE OF UPR WAVE. END RESULT MAY BE INCRG UPR CLDS IN NRN ZONES
THIS AFTN.
DESPITE LESS CLD CVR THAN YDA...MAXIMA TDA SHUD BE COMPARABLE TO THOSE
OF YDA...GIVEN ADVCTN OF SLGLTY COOLER TEMPS NR H85.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM WEDNESDAY/...
WITH DEPARTURE OF UPR WAVE...CDFNT XPCD TO BCM QUASISTATIONARY
TNGT. MSTR ALONG THIS BNDRY SHUD BE SUFFICIENT FOR LOW CLD DVLPMT
ACRS SRN PA...WHICH WILL ADVCT INTO FCST AREA WITH WNWLY LOW LVL
FLOW. HAVE CONTD MOCLDY SKIES TNGT NRN ZONES.
INCRG CVRG OF LWR CLDS TNGT WILL PRECLUDE EFFICIENT RADIATIONAL
COOLING...KEEPING MINIMA SLGTLY ABV VALUES SEEN THIS MRNG AND
SUPPRESSING FOG ISSUES.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
500MB HEIGHT/ANOMALY PATTERN DURING THE PAST 5 DAYS SHOWS A
WEAKENING WESTERN CONUS TROUGH...WITH AN EASTERN CONUS RIDGE IN
PLACE. MEANWHILE...A JET STRENGTHENS OVER THE NORTHERN PACIFIC.
WATER VAPOR LOOP SHOWS A VIGOROUS SHORT WAVE TROUGH NEARING THE
NORTHERN GREAT LAKES FROM THE WEST...AS THE WESTERN TROUGH
ELONGATES...LEAVING AN UPPER LOW TO MEANDER EAST OVER THE FOUR
CORNERS REGION. RIDGING IS IN PLACE OVER THE EASTERN CONUS...
ALBEIT FLATTENING OVER THE GREAT LAKES AS THE DISTURBANCE
APPROACHES. ACARS 400-250MB WIND OBSERVATIONS REVEAL A 100-145KT
JET FROM THE UPPER LOW NEAR THE FOUR CORNERS REGION...CURVING
ANTICYCLONICALLY FROM THE HUDSON BAY OVER THE NEW ENGLAND COAST.
THE LATE EVENING SURFACE MAP FEATURED A WEAKENING 1028MB HIGH
PRESSURE SYSTEM ACROSS THE MID ATLANTIC...WITH A BACKDOOR COLD
FRONT SLIDING SOUTHWEST INTO NEW YORK. ANOTHER COLD FRONT WAS
NEARING THE MISSISSIPPI RIVER.
12Z GFS ENSEMBLES AND LAST SEVERAL RUNS OF GFS/EUROPEAN/CANADIAN
MODELS ARE IN GENERALLY GOOD AGREEMENT THROUGH THE LONG RANGE. HIGH
PRESSURE SURFACE AND ALOFT WEAKEN DURING THE MIDWEEK AS A
DISTURBANCE FROM THE NORTH CENTRAL CONUS 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...ALTHOUGH CANT RULE OUT A LIGHT QPF EVENT.
GUIDANCE BEGINS TO DIVERGE HEADING INTO THE WEEKEND WITH THE
STRENGTH AND TIMING OF THE NEXT TROUGH APPROACHING FROM THE
PACIFIC NORTHWEST. LAST 2 RUNS OF THE EUROPEAN HAVE THE STRONGEST
SURFACE REFLECTION...WHICH SUGGESTS THE POTENTIAL FOR RAIN
DEVELOPING FRIDAY INTO SATURDAY. GFS/CANADIAN ARE WEAKER UNTIL THE
SYSTEM DEVELOPS ACROSS THE WESTERN ATLANTIC...WHICH CUTS DOWN
PRECIPITATION CHANCES CONSIDERABLY. HAVE INCREASED POPS PARTICULARLY
ACROSS THE SOUTHERN ZONES...BUT WILL HOLD OFF ON FURTHER INCREASES
UNTIL GREATER GUIDANCE CONSISTENCY CAN BE ESTABLISHED.
SURFACE HIGH PRESSURE WILL BUILD SLOWLY INTO THE REGION DURING
NEXT WEEKEND WITH THE PASSAGE OF AN UPPER TROUGH. COOL BREEZY
CONDITIONS EXPECTED UNDER CLEARING SKIES.
&&
.AVIATION /07Z TUESDAY THROUGH SATURDAY/...
PATCHY FOG IMPACTING TERMINALS ATTM WILL ERODE BY MRNG...WITH
GENLY UPR LVL CLDS XPCD AS LGT SWLY WINDS DVLP AMID SFC TROF. WITH
MSTR ADVCTN AT 5-7KFT TNGT...WILL CARRY SCT-BKN DECK AT THIS LVL
AFTER 15/00Z.
WEAKENING HIGH PRESSURE CONTINUES INTO THE MID WEEK...WITH
PERHAPS SPOTTY FOG AT CLIMATOLOGICALLY FAVORED LOCATIONS. WEAK
FRONTAL BOUNDARY DROPS SLOWLY ACROSS THE REGION DURING THE LATTER
PORTION OF THE WORK WEEK INTO SATURDAY...BRINGING A CHANCE OF RAIN
/WITH PRIMARILY MVFR-VFR CONDITIONS/. PRELIMINARY LOOK TOWARD THE
WEEKEND SHOWS A GOOD CHANCE OF GUSTY NORTHWESTERLY WINDS AS COOL HIGH
PRESSURE BUILDS INTO THE REGION LATE SATURDAY AND SUNDAY.
&&
.MARINE...
LGT WINDS TDA AND TNGT WITH SFC TROF IN VCTY. NO MARINE HAZARDS XPCD
THRU TNGT.
WEAKENING 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 IN THE WORK WEEK WITH THE PASSAGE
OF A COLD FRONT. IT IS UNCERTAIN AT THIS TIME WHETHER DEVELOPING
LOW PRESSURE BRINGS RAIN TO THE REGION HEADING INTO THE WEEKEND.
THERE IS A GOOD CHANCE OF SMALL CRAFT ADVISORY WINDS AS COOL HIGH
PRESSURE BUILDS SLOWLY INTO THE REGION THIS WEEKEND.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.
&&
$$
KRAMAR/ROGOWSKI
AREA FORECAST DISCUSSION...UPDATED
NWS MARQUETTE MI
119 PM EDT WED OCT 15 2008
UPDATED FOR 18Z AVIATION DISCUSSION
.UPDATE...
UPDATED THE GRIDS/ZFP THIS MORNING TO ACCOUNT FOR MORE LIGHT
PRECIPITATION CENTRAL AND STEADY TYPE PRECIPITATION SOUTH AND
EAST...WITH A QUICKER END CENTRAL. ANOTHER CHANGE INCLUDED UPPING
SKY COVER ACROSS THE ENTIRE LAND MASS THIS MORNING. ZFP HAS ALREADY
BEEN ISSUED. WILL CONTINUE TO MONITOR WINDS...AS THEY ARE BELOW 15
KNOTS SO FAR THIS MORNING...EXCEPT ON THE LAKE WHERE GUSTS UP TO 32
KNOTS HAVE ALREADY BEEN REPORTED (ROCK OF AGES).
&&
.DISCUSSION...
UPPER AIR PATTERN CONSISTS OF A 500 MB TROUGH ACROSS THE CENTRAL
U.S. WITH RIDGING OVER THE SE AND EASTERN U.S. THERE ARE 2
SHORTWAVES OF INTEREST IN THE TROUGH WITH ONE OVER ERN CO AND
WESTERN KS AND ONE NEAR LAKE WINNIPEG. CWA GETS SPLIT FROM BOTH OF
THESE SHORTWAVES AS THE ONE IN CANADA STAYS NORTH AND THE ONE OVER
KS MOVES TO THE SOUTH. PATTERN THEN SWITCHES ON THU WITH TROUGHING
DIGGING INTO THE ERN U.S. AND FLATTENING THE RIDGE OVER THE SE AND
BY SAT...NAM SHOWS A 500 MB RIDGE BUILDING OVER THE DESERT SW.
FORECAST PROBLEM FOR TODAY IS IF PCPN CAN MAKE IT INTO THE
CWA...ESPECIALLY THE SOUTHERN CWA. QUICK LOOK AT 00Z SOUNDING FROM
KMPX...KAPX AND KGRB ALL SHOW VERY DRY LOW AND MID LEVELS AND THIS
IS CONFIRMED FROM TAMDAR SOUNDINGS FROM KSAW. THIS DRY AIR WAS
EXTENSIVE...BUT ERODED AWAY RAPIDLY OVERNIGHT AS RAIN HAS MADE IT TO
THE OFFICE AND ALSO AS FAR NORTH AND EAST AS KERY. GFS QPF HAD THIS
NAILED PERFECTLY AND USED THIS MODEL FOR THIS FORECAST THIS MORNING.
BASICALLY...HAD TO UP POPS AND BRING THEM FURTHER NORTH DUE TO THE
DRY AIR ERODING. HAD LIKELY POPS IN EARLY THIS MORNING ACROSS THE
SOUTHERN HALF OF THE CWA AND CHANCE POPS IN THE CENTRAL AND KEPT
CHANCE POPS IN THIS MORNING FOR THE SOUTHERN HALF AND EASTERN HALF
OF THE CWA. THE MOISTURE MOVES OUT THIS AFTERNOON AND WENT DRY FOR
THE FORECAST AFTER THAT. LOOKED AT POSSIBILITY OF LAKE EFFECT PCPN
BEYOND THAT AND IT LOOKS MINIMAL. GFS DOES TAKE TEMPERATURES AT 850
MB DOWN TO -4C...BUT LAKE TEMPERATURES ARE ABOUT 7C-9C WHICH IS
BORDERLINE FOR LAKE EFFECT. PROBLEM IS GFS SOUNDINGS SHOW INVERSION
HEIGHT UP TO 5000 FEET WITH INVERTED-V AT LOW LEVELS AT KCMX...KSAW
AND KERY. THIS INVERTED-V AND BORDERLINE DELTA-T SHOULD KEEP IT DRY
WITH ONLY LAKE EFFECT CLOUDS BEING PRODUCED. OVERALL...BESIDES TODAY
WITH THE CHANGES FOR POPS...DID NOT MAKE MANY CHANGES TO
TEMPERATURES OR WEATHER.
&&
AVIATION (FOR THE 18Z TAF ISSUANCE)...
SOME MINOR CHANGES TO THE SHORT TERM PERIOD OF THE TAFS...WITH MOST
ADJUSTMENTS MADE TO KSAW. INITIAL MID/HIGH CLOUDS WILL MOVE OUT OF
KSAW QUICKLY...WHILE MVFR CLOUDS AROUND 2KFT...CURRENTLY FROM KCMX
TO KLNL ALONG COLD FRONT...MOVE INTO KSAW BETWEEN 19-20Z.
THUS...HAVE ADDED A PERIOD OF LOWER CLOUDS THERE BEFORE TRENDING
CIGS UPWARD TOWARDS EVENING...SIMILAR TO UPSTREAM CONDITIONS IN NRN
MN. AS FOR KCMX...CONTINUED MVFR COND...BUT LOWER CIGS SLIGHTLY TO
1.5KFT...AS INITIAL CLDS MOVE THROUGH WITH FRONTAL PASSAGE. GUSTY
WINDS LOOK TO BE IN GOOD SHAPE...WITH GUSTS ALREADY REACHING 28KTS
AT 17Z. BEYOND FIRST 6 HRS...DID NOT MAKE MANY ADJUSTMENTS TO SITES
AS SCT/BKN LK ENHANCED CLOUDS EXPECTED NEAR LK SUPERIOR THROUGH
TOMORROW AFTN.
&&
.MARINE (FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)...
LOW PRESSURE WILL MOVE EAST ACROSS NORTHERN ONTARIO TODAY AND DRAG A
COLD FRONT THROUGH THE UPPER GREAT LAKES. W-NW WINDS ASSOC WITH THE
COLD FRONT WILL FREQUENTLY GUST TO 35 KNOTS THIS AFTERNOON INTO THE
EARLY OVERNIGHT TONIGHT AS THE MIXED LAYER OVER THE OPEN WATER
BECOMES DEEPER WITH THE ARRIVAL OF COLDER AIR. HIGH PRESSURE
BEGINNING TO BUILD INTO THE UPPER GREAT LAKES LATE TONIGHT WILL
CAUSE GALES TO END. THE HIGH PRESSURE WILL REMAIN FAIRLY STATIONARY
OVER THE GREAT 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 WARNING FROM 8 PM THIS EVENING TO 4 AM EDT THURSDAY FOR
LSZ251-267.
GALE WARNING FROM 5 PM THIS AFTERNOON TO 4 AM EDT THURSDAY FOR
LSZ266.
GALE WARNING UNTIL MIDNIGHT EDT TONIGHT FOR LSZ243>247-264-265.
GALE WARNING UNTIL 11 PM EDT THIS EVENING FOR LSZ263.
GALE WARNING FROM 7 PM THIS EVENING TO 2 AM EDT THURSDAY FOR
LSZ249-250.
GALE WARNING UNTIL 2 AM EDT THURSDAY FOR LSZ248.
GALE WARNING UNTIL 8 PM EDT THIS EVENING FOR LSZ242.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...KF
DISCUSSION...GM
AVIATION...SRF
MARINE...VOSS
AREA FORECAST DISCUSSION...UPDATED
NWS MARQUETTE MI
117 AM EDT TUE OCT 14 2008
UPDATED AVIATION DISCUSSION FOR 06Z TAF ISSUANCE
.SYNOPSIS... ISSUED AT 355 PM EDT
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW SHARP UPR TROF IN
THE PLAINS UPSTREAM OF HI AMPLITUDE RDG CENTERED OVER THE OH VALLEY.
SSW FLOW BTWN SFC-H85 HI PRES UNDER THE UPR RDG AND APRCHG COLD FNT
IN MN THAT IS ON ERN FLANK OF UPR TROF HAS BROUGHT ANOTHER
UNSEASONABLY WARM DAY TO UPR MI...12Z H85 TEMP WAS 15C AT APX.
ALTHOUGH THIS FLOW IS ALSO TAPPING DEEPER MSTR WITH 12Z PWAT OF 1.59
INCHES AT MPX (ALMOST 300 PCT OF NORMAL)...THERE IS A SHARP GRADIENT
OF DEEP MSTR ACRS THE UPR LKS/MIDWEST AS THE 12Z PWAT AT APX IS ONLY
0.61 INCH. EARLIER TAMDAR SDNG FM RHI SHOWED MUCH OF THE MSTR THERE
WAS CONFINED BLO INVRN ARND H8 OR SO AND MID LVL DRY AIR ASSOCIATED
WITH UNSEASONABLY STRG UPR RDG/HI MID LVL HGTS. SO ALTHOUGH SOME SC
IS SPRDG INTO THE FA BLO THIS INVRN...THERE IS ONLY A RELATIVELY
NARROW BAND OF SHRA ON THE WARM SIDE OF THE APRCHG COLD FNT WHERE
SHRTWV LIFTING NNEWD FM IA IS ERODING THE INVRN AND BRINGING DEEPER
MSTR ALMOST TO H3 AS SHOWN ON THE 12Z MPX RAOB. THESE PRE-FRONTAL
SHRA ARE MOVING INTO THE WRN ZNS THIS AFTN. QUITE A BIT OF SHRA ARE
FALLING ON THE COOL SIDE OF THE FNT WITH UPR WINDS NEARLY PARALLEL
TO THE BNDRY SEPARATING THE UNSEASONABLY WARM AIRMASS OVER THE FA FM
MUCH COOLER AIR IN THE NRN PLAINS (12Z H85 TEMP WAS -6C AT BIS). THE
BAND OF SHRA ON THE COOL SIDE OF THE BNDRY EXTENDS S ALL THE WAY TO
OK ON THE ACYC SIDE OF STRG RIBBON OF UPR WINDS IN THE PLAINS AND ON
THE ERN FLANK OF THE TROF TO THE W. OTRW...POTENT SHRTWV OVER THE
LLVL COOL AIR IN THE PLAINS IS LIFTING NEWD INTO SCNTRL CAN. ANOTHER
SHRTWV IS ROUNDING THE BASE OF THE TROF IN THE DESERT SW.
&&
.DISCUSSION... ISSUED AT 355 PM EDT
...SHORT TERM (TNGT AND TUE)...
MAIN FCST CONCERNS DURING THIS PD ARE SHRA CHCS ASSOCIATED WITH COLD
FROPA AND POTENTIAL FOR/COVG OF STRONG POST-FRONTAL W WINDS.
TNGT...12Z NAM HAS TRENDED IN DIRECTION OF EARLIER MODEL CONSENSUS
LED BY GFS SHOWING STRG SHRTWV NOW MOVING INTO SCNTRL CAN TENDING TO
SHIFT MORE E AND CRASH UPR HGTS ACRS ONTARIO (12 HR H5 HGT FALLS
FCST UP TO 160M JUST N OF LK SUP BTWN 00Z AND 12Z TUE). WITH UPR
FLOW TENDING TO BCM MORE PERPENDICULAR TO THE APRCHG COLD FNT...
EXPECT THIS FEATURE TO ACCELERATE E TNGT AND PASS ERY ARND 06Z. WITH
THE LLVL FLOW VEERING AND INCRSG SUBSIDENCE/DRY ADVCTN BEHIND THE
FNT...EXPECT THE POST FRONTAL SHRA TO TEND TO DIMINISH AS WELL. SO
WL GO WITH CATEGORICAL POPS OVER THE W LOWERING TO HI CHC OVER THE
E. WITH SHARPLY LOWERING HGTS/PRES TO THE N...EXPECT POST-FRONTAL W
WINDS TO INCRS AS WELL. MODEL FCST WIND SPEEDS IN PRESENCE OF
SUBSIDENCE AND DESCENDING WIND MAX/EVALUATION OF LOCAL HI WIND
CHECKLIST SUGS NEED FOR WIND ADVY FOR THE EXPOSED KEWEENAW
PENINSULA. MOS FCST LO TEMPS SEEM UNREASONABLY HI FOR TNGT
CONSIDERING THE CHILLY AIRMASS UPSTREAM IN THE NRN PLAINS...SO
TENDED WELL BLO GUIDANCE WITH RELATIVELY SHALLOW INFUSION OF COLDER
AIR THAT MIGHT OTRW BIAS MOS TOO HI.
TUE...ALTHOUGH SOME SC WL IMPACT THE NRN TIER ASSOCIATED WITH THE
PASSAGE OF LLVL THERMAL TROF UNDER SHARP SUBSIDENCE INVRN...THE DAY
WL BE DRY AND MORE AUTUMNAL THAN TDAY. THE SCNTRL SHOULD SEE PLENTY
OF SUNSHINE WITH DOWNSLOPING W WIND AND INFUSION OF LLVL DRY AIR.
OTRW...GUSTY WINDS WL DIMINISH WITH APRCH OF HI PRES RDG AXIS.
MIXING TO INVRN BASE ARND H875 ON GFS FCST SDNGS YIELDS HI TEMPS
BTWN THE LO 50S OVER THE N TO ARND 60 OVER THE S.
...LONG TERM (TUE NGT THRU MON)...
QUIET WEATHER EXPECTED FOR TUESDAY NIGHT AS WEAK HIGH PRESSURE
BEGINS TO SHIFT OUT OF THE FA. NEXT CHANCE FOR PRECIPITATION IS IN
RESPONSE TO A LOW DEVELOPING OUT OF THE SOUTHERN PLAINS WHICH SHIFTS
TO OHIO BY THURSDAY MORNING. RECENT MODEL TRENDS HAVE BEEN SHIFTING
BACK AND FORTH AS FAR THE NORTHERN EXTENT OF THE PRECIPITATION
SHIELD WITH THIS LOW. AS OF NOW...IT APPEARS A CONSENSUS IS BEING
MET AND ONLY FAR SOUTHERN MENOMINEE AND ALONG THE LAKE MICHIGAN
SHORELINE EASTWARD WILL BE IMPACTED IF AT ALL. STILL SKEPTICAL
THOUGH THAT ANY RAIN WILL VERIFY SINCE BEST MOISTURE REMAINS NEAR
AND ALONG FRONTAL BOUNDARIES ASSOCIATED WITH THE STRENGTHENING LOW.
AT THE SAME TIME...A WEAK COLD FRONT WILL ALSO CROSS OUR CWA AS ITS
PARENT LOW MOVES ACROSS ONTARIO ON WEDNESDAY. THIS FRONTAL PASSAGE
DOESN/T LOOK TO DO MUCH EXCEPT INCREASE WINDS TO 30 KNOTS OVER LAKE
SUPERIOR. BEHIND THIS FRONT...WINDS TURN NORTHERLY AND REASONABLY
COLD AIR FILTERS IN. WITH 850HPA TEMPS FALLING TO AROUND -3 TO -5C
NEED TO CONSIDER LAKE EFFECT CLOUDS AND PRECIPITATION POTENTIAL.
MAINTAINED LOW END POPS ACROSS FA WITH SLIGHTLY HIGHER VALUES ACROSS
AREAS FAVORED BY A NORTH WIND. AT AROUND 10-12C THE CURRENT LAKE
SUPERIOR TEMPERATURES WOULD SUPPORT THIS SCENARIO HOWEVER SOME
UNCERTAINTY HOW MUCH TONIGHT/S FRONT WILL DROP LAKE TEMPS AS IT
PASSES. LATEST LAKE SUPERIOR TEMPERATURE FORECAST SHOWS A DROP OF
ONLY AROUND 2C WITH THE FRONTAL PASSAGE SO LAKE EFFECT COULD BE
MARGINAL IN THE ABSENCE OF SYNOPTIC ENHANCEMENT. ALSO AIRMASS IS
FAIRLY DRY AS INDICATED BY SHALLOW CLOUD DEPTHS PROGGED BY BOTH THE
NAM AND GFS BUFKIT PROFILES. LAKE EFFECT CLOUD POTENTIAL IS MARGINAL
ON THE WEST HALF DESPITE LAKE TEMPS. WIND FIELD IS QUITE RAGGED
BEHIND WEDNESDAY/S FRONT THOUGH WED NIGHT ENOUGH OF A FETCH IS
PRESENT TO AT LEAST INCREASE CLOUD COVER. NEXT SYSTEM OF INTEREST IS
A FRONT PROGGED TO PASS THROUGH THE FA LATE THIS WEEKEND. KEPT LOW
END POPS INTO SUNDAY NIGHT AS EC SOLUTION INDICATES FRONTAL PASSAGE
SUNDAY NIGHT WHICH IS A BIT SLOWER THAN THE GFS SOLUTION. GFS SOLN
ALSO KEEPS BEST MOISTURE AND MID LEVEL CONVERGENCE NEAR AND NORTH OF
PARENT LOW IN ONTARIO.
&&
AVIATION (FOR THE 06Z TAF ISSUANCE)...
AT KCMX...STRONG/GUSTY W WINDS WILL CONTINUE THRU THE NIGHT UNDER
CAA REGIME WITH WIND DIRECTION ALSO FAVORABLE FOR TERRAIN
ENHANCEMENT TO WIND. EXPECT THE GUSTY WINDS TO BEGIN DIMINISHING
AROUND SUNRISE WITH APPROACH OF SFC HIGH PRES RIDGE/WEAKER PRES
GRADIENT. OTHERWISE...VFR CONDITIONS SHOULD PREVAIL FOR THE BULK OF
THE FCST PERIOD WITH ONE EXCEPTION. THERE MAY BE A SHORT PERIOD OF
MVFR CIGS DURING THE MORNING IN CONJUNCTION WITH PASSING LOW-LEVEL
THERMAL TROF. IF MVFR CIGS DEVELOP...CLOUDS SHOULD SCATTER OUT BY
AFTN WITH ARRIVAL OF DRIER AIR.
AT KSAW...MVFR CLOUD DECK WILL SCATTER OUT TO VFR CONDITIONS OVER
THE NEXT FEW HRS AS SHARP DRYING OCCURS IN THE WAKE OF COLD FROPA.
W WINDS BEHIND FRONT WILL NOT BE NEARLY AS STRONG AT KSAW AS AT KCMX
WHICH HAS OVERLAKE TRAJECTORIES AND FAVORABLE TERRAIN ORIENTATION.
DOWNSLOPING WRLY FLOW SHOULD LIMIT POTENTIAL FOR REDEVELOPMENT OF
ANY MVFR CIGS IN THE MORNING. THUS...EXPECT VFR CONDITIONS TO
PREVAIL THRU THE END OF THE FCST PERIOD ONCE MVFR CIGS EXIT OVER THE
NEXT FEW HRS.
&&
.MARINE (FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)...
LOW PRESSURE OVER WESTERN ONTARIO WILL DEEPEN AS IT MOVES TO
NORTHERN QUEBEC BAY BY MIDDAY TUESDAY. THIS LOW WILL DRAG A COLD
FRONT ACROSS LAKE SUPERIOR TONIGHT. EXPECT WEST GALES TO DEVELOP
OVER ALL BUT FAR WESTERN LAKE SUPERIOR IN THE WAKE OF THIS FRONT.
HIGH PRESSURE WILL TEMPORARILY BUILD INTO THE UPPER GREAT LAKES ON
TUESDAY AND CAUSE WINDS TO DIMINISH. LOOK FOR A LOW PRESSURE TROUGH
APPROACHING FROM THE NORTHWEST TO CROSS LAKE SUPERIOR ON WEDNESDAY.
BY THURSDAY...HIGH PRESSURE WILL BUILD INTO THE UPPER GREAT LAKES
AND REMAIN STATIONARY THROUGH SATURDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WIND ADVY UNTIL 6 AM EDT TUE MIZ001-003.
LAKE SUPERIOR...
GALE WARNING UNTIL 10 AM EDT TUE LSZ250-251-265>267.
GALE WARNING UNTIL 8 AM EDT TUE LSZ243-244-263-264.
LAKE MICHIGAN...NONE.
&&
$$
SYNOPSIS/SHORT TERM DISCUSSION...KC
LONG TERM...PEARSON
AVIATION...ROLFSON
MARINE...KC
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