Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 10/27/12
AREA FORECAST DISCUSSION
NWS SAN JOAQUIN VALLEY - HANFORD CA
200 PM PDT THU OCT 25 2012
.SYNOPSIS...
WEAK HIGH PRESSURE HAS BEGUN TO MOVE OVER THE REGION. GENERALLY
MOSTLY CLEAR SKIES ARE EXPECTED THROUGH THE WEEKEND...EXCEPT
PATCHY VALLEY FOG IS POSSIBLE TONIGHT AND INTO FRIDAY MORNING.
TEMPERATURES WILL GRADUALLY WARM TO A FEW DEGREES ABOVE AVERAGE BY
THE WEEKEND.
&&
.DISCUSSION...
VISIBLE SATELLITE IMAGERY IS SHOWING LOW LEVEL CIRCULATION OFF THE
MONTEREY BAY COAST AND SLOWLY DRIFTING SOUTHWARD. HIGH-RES RAPID
REFRESH(HRRR) IS SHOWING DECREASING CLOUD COVER OVER THE VALLEY AS
THE LOW LEVEL CIRCULATION TRAVELS DUE SOUTH AND FURTHER OFFSHORE.
CURRENT TIMING HAS THE VALLEY CLEARING OUT JUST BEFORE SUNSET
BASED ON BOTH HRRR AND SREF SOLUTIONS. AT THIS POINT...THE BROAD
CYCLONIC CIRCULATION OVER THE WEST COAST CONTINUES TO SHIFT EAST
WITH A HIGH PRESSURE RIDGE AXIS MOVING CLOSER TO THE WEST COAST ON
FRIDAY. YET...SHORT RANGE MODELS DO NOT RELAX THE NORTHWESTERLY
FLOW ALOFT UNTIL AFTER FRIDAY AFTERNOON. THEREFORE...WITH LOCALLY
BREEZY WINDS ALOFT...FOG AND EXTREMELY COLD SURFACE TEMPERATURES
WILL NOT BE FAVORED OVER THE SAN JOAQUIN VALLEY FRIDAY MORNING.
HOWEVER...WILL KEEP A MENTION OF PATCHY FOG OVER THE SAN JOAQUIN
VALLEY FOR MORE RURAL AREAS THAT HAVE LESS OF A THRESHOLD TO FOG-
UP. IN ADDITION...TEMPERATURES WILL DROP OVERNIGHT...LOWER THEN
THURSDAY MORNING BUT NOT BY MUCH AS LOCAL WINDS WILL CONTINUE TO
BLOW FOR ONE MORE NIGHT.
AFTER FRIDAY...THE GENERAL TREND IS FOR CLEAR CONDITIONS WITH
WARMING TEMPERATURES THROUGH SUNDAY. GFS/ECMWF/UKMET/NOGAPS ALL
IN GOOD AGREEMENT WITH PLACING THE RIDGE AXIS OVER CALIFORNIA BY
SUNDAY AS THEY ALL FORM A REX BLOCKING PATTERN OVER THE NORTH-
CENTRAL PACIFIC. BY SUNDAY...GUIDANCE PLACES VALLEY MAX TEMP/S
SOME 3 TO 5 DEG-F ABOVE NORMAL BEFORE THE START OF ANOTHER COOLING
TREND. TOWARD NEXT WEEK...ALL LONGER RANGE MODELS ATTEMPT TO
BREAKDOWN THE REX BLOCK AND EJECT A TROF TOWARD THE PACIFIC
NORTHWEST/NOR- CAL BY TUESDAY NIGHT/WEDNESDAY. FEEL THAT MODELS
MAY BE PREMATURELY BREAKING DOWN THE REX BLOCK TOO SOON...WHICH
COULD LAST FOR A WEEK. DUE TO ALL MODELS DOING THIS BREAK DOWN...
CERTAINTY IS UP SLIGHTLY ON THE SOLUTION FOR EARLY NEXT WEEK. IF
THE TROF APPROACHES THE WEST COAST NEXT WEEK...IT WILL HAVE THE
DEAL WITH SANDY ALONG THE EAST COAST. EVEN WITH MODEL UNCERTAINTY
ON THE TROPICAL SYSTEM...SANDY...IT WILL EXIST OVER THE EAST COAST
EARLY NEXT WEEK. THEREFORE...THE RIDGE OVER THE MID-WEST WILL HAVE
TO AMPLIFY AS IT ADJUSTS TO THE APPROACHING TROF. MODELS DO
INDICATE THAT THE PRECIP BAND PUSHING ONTO CALIFORNIA WILL BE
FORCED TO SHIFT NORTHEAST AND POSSIBLY MISS CENTRAL CALIFORNIA.
THEREFORE...WILL ONLY MENTION A SLIGHT CHANCE OF PRECIP...STARTING
TUESDAY NIGHT...OVER THE NORTHERN THIRD OF THE DISTRICT FOR AREAS
FROM FRESNO COUNTY NORTHWARD.
&&
.AVIATION...
VFR CONDITIONS WILL PREVAIL THRU 00Z SATURDAY...EXCEPT LOCAL MVFR
IN MIST IN THE SAN JOAQUIN VALLEY 12Z TO 17Z FRIDAY.
&&
.AIR QUALITY ISSUES...
NONE.
&&
.CERTAINTY...
THE LEVEL OF CERTAINTY FOR DAYS 1 AND 2 IS HIGH.
THE LEVEL OF CERTAINTY FOR DAYS 3 THROUGH 7 IS MEDIUM.
THIS INFORMATION IS PROVIDED AS PART OF A TRIAL PROJECT CONDUCTED
BY THE NATIONAL WEATHER SERVICE SAN JOAQUIN VALLEY - HANFORD.
CERTAINTY LEVELS INCLUDE LOW...MEDIUM...AND HIGH. PLEASE VISIT
WWW.WEATHER.GOV/HNX/CERTAINTY.PHP /ALL LOWER CASE/ FOR ADDITIONAL
INFORMATION AND/OR TO PROVIDE FEEDBACK.
&&
.CLIMATE...
RECORDS
SITE DATE HI_MAX:YEAR LO_MAX:YEAR HI_MIN:YEAR LO_MIN:YEAR
KFAT 10-25 91:1966 61:1998 62:1982 36:1971
KFAT 10-26 89:2003 57:2004 58:1927 35:1939
KFAT 10-27 89:2003 58:1896 61:1987 35:1970
KBFL 10-25 94:1917 62:1939 66:1982 35:1899
KBFL 10-26 92:2003 58:1996 61:1959 35:1939
KBFL 10-27 99:1906 56:2004 64:1987 34:1919
&&
.HNX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
PUBLIC...MOLINA
AVN/FW...BEAN
SYNOPSIS...BSO
WEATHER.GOV/HANFORD
AREA FORECAST DISCUSSION
NWS MIAMI FL
1139 PM EDT FRI OCT 26 2012
.UPDATE...
UPDATED THE FORECAST WITH THE LATEST WIND GUIDANCE. BUT NO CHANGES
WERE REQUIRED FOR THE WATCHES OR WARNINGS IN EFFECT WITH A WIND
ADVISORY STILL IN EFFECT ACROSS THE EASTERN HALF OF THE PENINSULA
AND A TROPICAL STORM WARNING STILL IN EFFECT FOR THE ATLANTIC
WATERS TO THE EAST OF PALM BEACH COUNTY.
60
&&
.PREV DISCUSSION... /ISSUED 858 PM EDT FRI OCT 26 2012/
UPDATE...
AS WINDS ACROSS THE REGION CONTINUE TO SLOWLY SUBSIDE...THIS
PROMPTED SOME CHANGES TO THE WATCHES AND WARNINGS FOR THE CWA. THE
TROPICAL STORM WARNING THAT WAS IN EFFECT FOR COASTAL PALM BEACH
COUNTY HAS BEEN DISCONTINUED. HOWEVER...NEED TO RE-EMPHASIZE THAT
THE TROPICAL STORM WARNING REMAINS IN EFFECT OVER NIGHT FOR THE
ATLANTIC WATERS TO THE EAST OF PALM BEACH COUNTY.
THE WIND ADVISORY ACROSS THE PENINSULA HAS ALSO BEEN UPDATED WITH
ONLY PALM BEACH...BROWARD AND MIAMI DADE COUNTIES NOW IN THE WIND
ADVISORY.
IN ADDITION...RECENT REGIONAL RADAR RETURNS INDICATE SHOWER
COVERAGE CONTINUING TO DECREASE ALTHOUGH THERE ARE STILL
WIDESPREAD SHOWERS ACROSS THE ATLANTIC WATERS WITH MAINLY ISOLATED
SHOWERS ELSEWHERE.
60
PREV DISCUSSION... /ISSUED 749 PM EDT FRI OCT 26 2012/
AVIATION...
SHRA COVERAGE HAS DIMINISHED ACROSS THE AREA QUITE CONSIDERABLY
THIS EVENING AS SANDY CONTINUES TO PUSH WELL TO THE NORTH OF THE
AREA. HOWEVER...KEPT VCSH MENTION THROUGH THE LATE EVENING HOURS
AT ALL THE EAST COAST SITES. LATEST HRRR SHOWS MOST OF THE
LINGERING SHRAS EXITING THE AREA OVER THE NEXT FEW HOURS.
GRADUALLY TRENDED WINDS DOWN THROUGH THE PERIOD. UNDERCUT LAMP
GUIDANCE QUITE A BIT AS THEY STILL SEEM TO BE TOO HIGH.
PREV DISCUSSION... /ISSUED 718 PM EDT FRI OCT 26 2012/
UPDATE...
AS THE WINDS ACROSS THE REGION CONTINUE TO SLOWLY SUBSIDE...THE TROPICAL
STORM WARNING WAS DROPPED EARLIER THIS EVENING FOR LAKE OKEECHOBEE
WITH A SMALL CRAFT ADVISORY IN EFFECT WITH WINDS ACROSS THE LAKE
REMAINING AROUND 20 TO 25 KNOTS SUSTAINED WITH HIGHER GUSTS TO
AROUND 35 KNOTS. SO THE ONLY AREAS REMAINING UNDER TROPICAL STORM
WARNING ARE THE ATLANTIC WATERS TO THE EAST OF PALM BEACH COUNTY
AND THE PALM BEACH COUNTY COASTAL ZONE. THE CURRENT FORECAST
PACKAGE IS ON TRACK INDICATING CHANCES OF PRECIPITATION AND GUSTY
WINDS OVER NIGHT FROM THE OUTER PERIPHERY OF HURRICANE SANDY. WINDS
ACROSS THE REGION ARE FORECAST TO START SLOWLY SUBSIDING AS
HURRICANE SANDY CONTINUES ON A NORTHERLY TRACK THIS EVENING AND
OVER NIGHT.
60
PREV DISCUSSION... /ISSUED 245 PM EDT FRI OCT 26 2012/
DISCUSSION...HURRICANE SANDY CONTINUES TO SLOWLY DRIFT NORTH
OVER THE FAR NORTHERN BAHAMAS. ITS SLOW MOVEMENT WILL CONTINUE TO
ALLOW FOR THE OUTER BANDS TO MOVE ACROSS THE EASTERN PORTIONS OF
SOUTH FLORIDA THROUGH THIS EVENING. HOWEVER, THE WIND FIELD HAS
NOT EXPANDED TO THE EXTENT THAT SOME OF THE MODELS WERE EARLIER
INDICATING SO TROPICAL STORM WARNINGS WERE DISCONTINUED FOR
COASTAL BROWARD AND MIAMI-DADE COUNTIES AND THE ADJACENT ATLANTIC
WATERS INCLUDING BISCAYNE BAY. TROPICAL STORM CONDITIONS WILL
REMAIN POSSIBLE IN THE HEAVIER BANDS ACROSS COASTAL REGIONS OF
PALM BEACH COUNTY. FOR BROWARD AND MIAMI-DADE COUNTIES, THE
WARNING WAS REPLACED WITH A WIND ADVISORY ALONG WITH HIGH SURF
ADVISORY AND THE MENTION OF HIGH RISK OF RIP CURRENTS.
AFTER TONIGHT, A MID LEVEL TROUGH WILL BE DEEPENING ACROSS CENTRAL
NORTH AMERICA THROUGH SATURDAY AND SANDY WILL BEGIN TO ACCELERATE
NORTHEAST AWAY FROM THE FLORIDA PENINSULA WITH MUCH DRIER CONDITIONS
FILTERING INTO THE REGION AND CLEARING SKY CONDITIONS. AT THIS
POINT, A POWERFUL TROUGH WILL BE EVOLVING OVER THE NEXT SEVERAL DAYS
ACROSS THE EASTERN U.S. AND THIS WILL SET THE STAGE TO BRING THE
FIRST SIGNIFICANT SURGE OF COOLER AND DRIER AIR FOR THE FALL SEASON
ACROSS SOUTH FLORIDA ARRIVING ON MONDAY. BY TUESDAY AND WEDNESDAY
MORNINGS, TEMPERATURES WILL BE NEARLY 10 DEGREES BELOW THE AVERAGE
FOR LATE OCTOBER. MINIMUM TEMPERATURES WILL RANGE THOSE MORNINGS
FROM AROUND 50 TO THE WEST OF LAKE OKEECHOBEE AND THE MID TO UPPER
50S ALONG BOTH COASTAL METRO AREAS EXCEPT AROUND 60 ALONG THE
ATLANTIC COAST.
MARINE...THE WIND OVER THE CWA WATERS TODAY WILL SWING FROM A
NORTHERLY DIRECTION TO A NORTHWEST DIRECTION...AND REMAIN
NORTHWEST DIRECTION TONIGHT INTO THIS WEEKEND. THE WIND SPEEDS
WILL BE AT LEAST 25 TO 30 MPH MOST OF THE CWA WATERS TODAY...WITH
EVEN GUSTS UP TO TROPICAL STORM CONDITIONS OVER THE PALM BEACH
ATLANTIC WATERS AND LAKE OKEECHOBEE. THE WIND SPEEDS WILL REMAIN
NEARLY STEADY TONIGHT OVER ALL OF THE CWA WATERS...WITH GUSTS TO
TROPICAL STORM CONDITIONS OVER MOST OF THE CWA WATERS. SO WILL
CONTINUE THE TROPICAL STORM WARNING FOR THE NORTHERN WATERS INTO
TONIGHT...EXCEPT FOR A SCA ADVISORY FOR THE GULF WATERS WITH A
GALE WATCH FOR TONIGHT.
FIRE WEATHER...DRIER AIR WILL FILTER DOWN THE PENINSULA OVER THE
WEEKEND BUT RH VALUES WILL REMAIN ABOVE CRITICAL LEVELS THROUGH SUNDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 72 83 69 82 / 50 10 - -
FORT LAUDERDALE 71 84 69 83 / 30 10 - -
MIAMI 72 85 70 83 / 30 10 - -
NAPLES 72 84 70 81 / 20 - - -
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...WIND ADVISORY UNTIL 6 AM EDT SATURDAY FOR COASTAL BROWARD-
COASTAL MIAMI DADE-COASTAL PALM BEACH-FAR SOUTH MIAMI DADE-
INLAND BROWARD-INLAND MIAMI DADE-INLAND PALM BEACH-METRO
BROWARD-METRO MIAMI DADE-METRO PALM BEACH.
HIGH SURF ADVISORY UNTIL 8 PM EDT SATURDAY FOR COASTAL PALM
BEACH.
HIGH RIP CURRENT RISK THROUGH SUNDAY EVENING FOR COASTAL BROWARD-
COASTAL MIAMI DADE.
AM...SMALL CRAFT ADVISORY UNTIL 8 PM EDT SUNDAY FOR BISCAYNE BAY-
COASTAL WATERS FROM DEERFIELD BEACH TO OCEAN REEF, FL OUT
20 NM-WATERS FROM DEERFIELD BEACH TO OCEAN REEF, FL
EXTENDING FROM 20 NM TO THE TERRITORIAL WATERS OF THE
BAHAMAS.
TROPICAL STORM WARNING FOR COASTAL WATERS FROM JUPITER INLET TO
DEERFIELD BEACH, FL OUT 20 NM-WATERS FROM JUPITER INLET TO
DEERFIELD BEACH, FL EXTENDING FROM 20 NM TO 60 NM.
SMALL CRAFT ADVISORY UNTIL 8 PM EDT SUNDAY FOR LAKE OKEECHOBEE.
GM...SMALL CRAFT ADVISORY UNTIL 8 PM EDT SUNDAY FOR COASTAL WATERS
FROM CHOKOLOSKEE TO BONITA BEACH, FL OUT 20 NM-COASTAL
WATERS FROM EAST CAPE SABLE TO CHOKOLOSKEE, FL OUT 20 NM-
GULF WATERS FROM CHOKOLOSKEE TO BONITA BEACH, FL EXTENDING
FROM 20 TO 60 NM.
&&
$$
DISCUSSION/MARINE/FIRE...60/BD
AVIATION/RADAR...10/CD
AREA FORECAST DISCUSSION
NWS MIAMI FL
858 PM EDT FRI OCT 26 2012
.UPDATE...
AS WINDS ACROSS THE REGION CONTINUE TO SLOWLY SUBSIDE...THIS
PROMPTED SOME CHANGES TO THE WATCHES AND WARNINGS FOR THE CWA. THE
TROPICAL STORM WARNING THAT WAS IN EFFECT FOR COASTAL PALM BEACH
COUNTY HAS BEEN DISCONTINUED. HOWEVER...NEED TO RE-EMPHASIZE THAT
THE TROPICAL STORM WARNING REMAINS IN EFFECT OVER NIGHT FOR THE
ATLANTIC WATERS TO THE EAST OF PALM BEACH COUNTY.
THE WIND ADVISORY ACROSS THE PENINSULA HAS ALSO BEEN UPDATED WITH
ONLY PALM BEACH...BROWARD AND MIAMI DADE COUNTIES NOW IN THE WIND
ADVISORY.
IN ADDITION...RECENT REGIONAL RADAR RETURNS INDICATE SHOWER
COVERAGE CONTINUING TO DECREASE ALTHOUGH THERE ARE STILL
WIDESPREAD SHOWERS ACROSS THE ATLANTIC WATERS WITH MAINLY ISOLATED
SHOWERS ELSEWHERE.
60
&&
.PREV DISCUSSION... /ISSUED 749 PM EDT FRI OCT 26 2012/
AVIATION...
SHRA COVERAGE HAS DIMINISHED ACROSS THE AREA QUITE CONSIDERABLY
THIS EVENING AS SANDY CONTINUES TO PUSH WELL TO THE NORTH OF THE
AREA. HOWEVER...KEPT VCSH MENTION THROUGH THE LATE EVENING HOURS
AT ALL THE EAST COAST SITES. LATEST HRRR SHOWS MOST OF THE
LINGERING SHRAS EXITING THE AREA OVER THE NEXT FEW HOURS.
GRADUALLY TRENDED WINDS DOWN THROUGH THE PERIOD. UNDERCUT LAMP
GUIDANCE QUITE A BIT AS THEY STILL SEEM TO BE TOO HIGH.
PREV DISCUSSION... /ISSUED 718 PM EDT FRI OCT 26 2012/
UPDATE...
AS THE WINDS ACROSS THE REGION CONTINUE TO SLOWLY SUBSIDE...THE TROPICAL
STORM WARNING WAS DROPPED EARLIER THIS EVENING FOR LAKE OKEECHOBEE
WITH A SMALL CRAFT ADVISORY IN EFFECT WITH WINDS ACROSS THE LAKE
REMAINING AROUND 20 TO 25 KNOTS SUSTAINED WITH HIGHER GUSTS TO
AROUND 35 KNOTS. SO THE ONLY AREAS REMAINING UNDER TROPICAL STORM
WARNING ARE THE ATLANTIC WATERS TO THE EAST OF PALM BEACH COUNTY
AND THE PALM BEACH COUNTY COASTAL ZONE. THE CURRENT FORECAST
PACKAGE IS ON TRACK INDICATING CHANCES OF PRECIPITATION AND GUSTY
WINDS OVER NIGHT FROM THE OUTER PERIPHERY OF HURRICANE SANDY. WINDS
ACROSS THE REGION ARE FORECAST TO START SLOWLY SUBSIDING AS
HURRICANE SANDY CONTINUES ON A NORTHERLY TRACK THIS EVENING AND
OVER NIGHT.
60
PREV DISCUSSION... /ISSUED 245 PM EDT FRI OCT 26 2012/
DISCUSSION...HURRICANE SANDY CONTINUES TO SLOWLY DRIFT NORTH
OVER THE FAR NORTHERN BAHAMAS. ITS SLOW MOVEMENT WILL CONTINUE TO
ALLOW FOR THE OUTER BANDS TO MOVE ACROSS THE EASTERN PORTIONS OF
SOUTH FLORIDA THROUGH THIS EVENING. HOWEVER, THE WIND FIELD HAS
NOT EXPANDED TO THE EXTENT THAT SOME OF THE MODELS WERE EARLIER
INDICATING SO TROPICAL STORM WARNINGS WERE DISCONTINUED FOR
COASTAL BROWARD AND MIAMI-DADE COUNTIES AND THE ADJACENT ATLANTIC
WATERS INCLUDING BISCAYNE BAY. TROPICAL STORM CONDITIONS WILL
REMAIN POSSIBLE IN THE HEAVIER BANDS ACROSS COASTAL REGIONS OF
PALM BEACH COUNTY. FOR BROWARD AND MIAMI-DADE COUNTIES, THE
WARNING WAS REPLACED WITH A WIND ADVISORY ALONG WITH HIGH SURF
ADVISORY AND THE MENTION OF HIGH RISK OF RIP CURRENTS.
AFTER TONIGHT, A MID LEVEL TROUGH WILL BE DEEPENING ACROSS CENTRAL
NORTH AMERICA THROUGH SATURDAY AND SANDY WILL BEGIN TO ACCELERATE
NORTHEAST AWAY FROM THE FLORIDA PENINSULA WITH MUCH DRIER CONDITIONS
FILTERING INTO THE REGION AND CLEARING SKY CONDITIONS. AT THIS
POINT, A POWERFUL TROUGH WILL BE EVOLVING OVER THE NEXT SEVERAL DAYS
ACROSS THE EASTERN U.S. AND THIS WILL SET THE STAGE TO BRING THE
FIRST SIGNIFICANT SURGE OF COOLER AND DRIER AIR FOR THE FALL SEASON
ACROSS SOUTH FLORIDA ARRIVING ON MONDAY. BY TUESDAY AND WEDNESDAY
MORNINGS, TEMPERATURES WILL BE NEARLY 10 DEGREES BELOW THE AVERAGE
FOR LATE OCTOBER. MINIMUM TEMPERATURES WILL RANGE THOSE MORNINGS
FROM AROUND 50 TO THE WEST OF LAKE OKEECHOBEE AND THE MID TO UPPER
50S ALONG BOTH COASTAL METRO AREAS EXCEPT AROUND 60 ALONG THE
ATLANTIC COAST.
MARINE...THE WIND OVER THE CWA WATERS TODAY WILL SWING FROM A
NORTHERLY DIRECTION TO A NORTHWEST DIRECTION...AND REMAIN
NORTHWEST DIRECTION TONIGHT INTO THIS WEEKEND. THE WIND SPEEDS
WILL BE AT LEAST 25 TO 30 MPH MOST OF THE CWA WATERS TODAY...WITH
EVEN GUSTS UP TO TROPICAL STORM CONDITIONS OVER THE PALM BEACH
ATLANTIC WATERS AND LAKE OKEECHOBEE. THE WIND SPEEDS WILL REMAIN
NEARLY STEADY TONIGHT OVER ALL OF THE CWA WATERS...WITH GUSTS TO
TROPICAL STORM CONDITIONS OVER MOST OF THE CWA WATERS. SO WILL
CONTINUE THE TROPICAL STORM WARNING FOR THE NORTHERN WATERS INTO
TONIGHT...EXCEPT FOR A SCA ADVISORY FOR THE GULF WATERS WITH A
GALE WATCH FOR TONIGHT.
FIRE WEATHER...DRIER AIR WILL FILTER DOWN THE PENINSULA OVER THE
WEEKEND BUT RH VALUES WILL REMAIN ABOVE CRITICAL LEVELS THROUGH SUNDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 72 83 69 82 / 50 10 - -
FORT LAUDERDALE 71 84 69 83 / 40 10 - -
MIAMI 72 85 70 83 / 30 10 - -
NAPLES 72 84 70 81 / 10 - - -
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...WIND ADVISORY UNTIL 6 AM EDT SATURDAY FOR COASTAL BROWARD-
COASTAL MIAMI DADE-FAR SOUTH MIAMI DADE-INLAND BROWARD-
INLAND MIAMI DADE-INLAND PALM BEACH-METRO BROWARD-METRO
MIAMI DADE-METRO PALM BEACH.
HIGH SURF ADVISORY UNTIL 8 PM EDT SATURDAY FOR COASTAL PALM
BEACH.
WIND ADVISORY UNTIL 6 AM EDT SATURDAY FOR COASTAL PALM BEACH.
HIGH RIP CURRENT RISK THROUGH SUNDAY EVENING FOR COASTAL BROWARD-
COASTAL MIAMI DADE.
AM...SMALL CRAFT ADVISORY UNTIL 8 PM EDT SUNDAY FOR BISCAYNE BAY-
COASTAL WATERS FROM DEERFIELD BEACH TO OCEAN REEF, FL OUT
20 NM-WATERS FROM DEERFIELD BEACH TO OCEAN REEF, FL
EXTENDING FROM 20 NM TO THE TERRITORIAL WATERS OF THE
BAHAMAS.
TROPICAL STORM WARNING FOR COASTAL WATERS FROM JUPITER INLET TO
DEERFIELD BEACH, FL OUT 20 NM-WATERS FROM JUPITER INLET TO
DEERFIELD BEACH, FL EXTENDING FROM 20 NM TO 60 NM.
SMALL CRAFT ADVISORY UNTIL 8 PM EDT SUNDAY FOR LAKE OKEECHOBEE.
GM...SMALL CRAFT ADVISORY UNTIL 8 PM EDT SUNDAY FOR COASTAL WATERS
FROM CHOKOLOSKEE TO BONITA BEACH, FL OUT 20 NM-COASTAL
WATERS FROM EAST CAPE SABLE TO CHOKOLOSKEE, FL OUT 20 NM-
GULF WATERS FROM CHOKOLOSKEE TO BONITA BEACH, FL EXTENDING
FROM 20 TO 60 NM.
&&
$$
DISCUSSION/MARINE/FIRE...60/BD
AVIATION/RADAR...10/CD
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
850 PM EDT FRI OCT 26 2012
...BREEZY CONDITIONS EXPECTED THROUGH TOMORROW...
.UPDATE (REST OF TONIGHT)...
00Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS A RATHER BLOCKY PATTERN IN
PLACE ACROSS NORTH AMERICA AND THE WESTERN ATLANTIC. PATTERN CONSISTS
OF BROAD LONGWAVE TROUGHING IN PLACE OVER MUCH OF THE CONUS...
FOLLOWED DOWNSTREAM BY SHARP RIDGING OVER THE NE STATE/EASTERN
CANADA...AND THEN SHARPLY DROPPING BACK INTO TROUGHING/UPPER LOW
PRESSURE OVER THE CANADIAN MARITIMES. AT THE BASE OF THE EASTERN
U.S. RIDGING WE FIND HURRICANE SANDY STILL CHURNING OFF THE FLORIDA
EAST COAST. MID/UPPER LEVEL MOISTURE ON THE WESTERN PERIPHERY OF THE
HURRICANES CIRCULATION HAS BEEN ERODING BACK TO THE EAST THE PAST
SEVERAL HOURS...WITH THE 00Z KTBW SOUNDING SHOWING A RATHER DRY
PROFILE ABOVE 600-700MB. NEEDLESS TO SAY...A FEW LINGERING SHOWERS
ARE STILL ONGOING OVER OUR FAR INLAND ZONES OF POLK/HIGHLANDS
COUNTIES...BUT EXPECT THIS ACTIVITY TO DIMINISH LATER TONIGHT INTO
EARLY SATURDAY MORNING AS THE DRIER AIR CONTINUES ITS EASTWARD
ADVANCE IN THE WAKE OF SANDY. ELSEWHERE...THE REMAINDER OF THE
FORECAST AREA WILL SEE A DRY CONDITIONS INTO SATURDAY. WINDS SHOULD
BECOME A BIT LESS GUSTY IN THE NEXT FEW HOURS...HOWEVER A TIGHT
PRESSURE GRADIENT REMAINS AND WINDS WILL HOLD UP MORE THAN USUAL FOR
THE OVERNIGHT PERIOD.
&
.PREVIOUS DISCUSSION (SATURDAY AND SUNDAY)...OVERALL SYNOPTIC PATTERN
FOR THE REGION WILL BE DRIVEN BY THE ACTIONS OF HURRICANE SANDY.
GRADIENT FLOW AROUND THE WESTERN PERIPHERY OF SANDY HAS STRENGTHENED
OVER THE PAST DAY PRODUCING WINDS IN THE 20-25 MPH RANGE WITH THE
HIGHEST VALUES INLAND IN THE SOUTHERN HALF OF THE CWA. GUSTS
EXCEEDING 35 MPH HAVE BEEN REPORTED AT A COUPLE WEATHER STATIONS.
FOR TONIGHT...EXPECTING WINDS AND GUSTS TO REDUCE SLIGHTLY OVER
NIGHT WITH THE MIXING HEIGHTS DROPPING BUT WILL QUICKLY PICK BACK UP
AGAIN AFTER SUNRISE. MODELS ARE SHOWING WINDS ~40 KT OFF THE SURFACE
DURING THE MID MORNING. EXPECT ANOTHER BREEZY DAY TOMORROW WITH
WINDS AGAIN IN THE 20-25 MPH (LOCALLY HIGHER INLAND AND FURTHER
SOUTH) WITH GUSTS EXCEED 30 MPH. WIND DIRECTION WILL VEER MORE NNW.
AT THE MOMENT...CURRENT FORECAST WILL FALL IN THE LAKE WIND ADVISORY
CRITERIA SO WILL MAINTAIN THAT ADVISORY THROUGH TOMORROW.
HAVE MAINTAINED A CHANCE OF SHOWERS INLAND TONIGHT BUT RAIN
CHANCES WILL GRADUALLY DECREASE THROUGH THE WEEKEND AS SANDY EXITS
NORTH. SUNDAY FORECAST REMAINS UNCHANGED WITH LOW RAIN CHANCES AND
WINDS DYING DOWN.
&&
.AVIATION...
VFR NEXT 24 HOURS. MAIN ISSUE WILL BE GUSTY WINDS WHICH WILL START
OUT NORTHERLY AND TREND NORTHWESTERLY TONIGHT AND SATURDAY AS
HURRICANE SANDY MOVES NORTH OF OUR LATITUDE. SOME LLWS ISSUES
POSSIBLE IF SURFACE WINDS BECOME LIGHTER THAN EXPECTED OVERNIGHT.
&&
.MARINE...A TIGHT PRESSURE GRADIENT IN PLACE OVER THE EASTERN GULF
OF MEXICO WILL CONTINUE ELEVATED WINDS AND SEAS TO ADVISORY LEVELS
THROUGH THE UPCOMING WEEKEND. WIND GUSTS LATER TONIGHT INTO SATURDAY
MAY APPROACH GALE FORCE AT TIMES. LATER THIS WEEKEND...SANDY WILL BE
EXITING TO THE NORTHEAST UP THE ATLANTIC SEABOARD...HOWEVER COOLER
AIR ARRIVING IN THE STORMS WAKE ALONG WITH A CONTINUED TIGHT
PRESSURE GRADIENT WILL RESULT IN ELEVATED WINDS TO CAUTIONARY OR
ADVISORY LEVELS LINGERING INTO MONDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 69 81 65 80 / 10 10 10 10
FMY 69 82 65 82 / 10 10 10 10
GIF 66 81 62 81 / 20 10 10 10
SRQ 69 82 66 81 / 10 10 10 10
BKV 65 80 58 79 / 10 10 10 10
SPG 72 81 69 78 / 10 10 10 10
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...LAKE WIND ADVISORY UNTIL 8 PM EDT SATURDAY FOR CHARLOTTE-
CITRUS-DESOTO-HARDEE-HERNANDO-HIGHLANDS-HILLSBOROUGH-
LEE-LEVY-MANATEE-PASCO-PINELLAS-POLK-SARASOTA-SUMTER.
BEACH HAZARDS STATEMENT THROUGH SATURDAY EVENING FOR
CHARLOTTE-HILLSBOROUGH-LEE-MANATEE-PINELLAS-SARASOTA.
SMALL CRAFT ADVISORY UNTIL 4 AM EDT SUNDAY FOR PINELLAS.
GULF WATERS...SMALL CRAFT ADVISORY UNTIL 4 AM EDT SUNDAY FOR BONITA
BEACH TO ENGLEWOOD OUT 20 NM-BONITA BEACH TO
ENGLEWOOD OUT 20 TO 60 NM-ENGLEWOOD TO TARPON SPRINGS
OUT 20 NM-ENGLEWOOD TO TARPON SPRINGS OUT 20 TO 60 NM-
TAMPA BAY WATERS-TARPON SPRINGS TO SUWANNEE RIVER OUT
20 NM-TARPON SPRINGS TO SUWANNEE RIVER OUT 20 TO 60
NM.
&&
$$
UPDATE/MARINE...MROCZKA
AVIATION...JILLSON
AREA FORECAST DISCUSSION
NWS MIAMI FL
749 PM EDT FRI OCT 26 2012
.AVIATION...
SHRA COVERAGE HAS DIMINISHED ACROSS THE AREA QUITE CONSIDERABLY
THIS EVENING AS SANDY CONTINUES TO PUSH WELL TO THE NORTH OF THE
AREA. HOWEVER...KEPT VCSH MENTION THROUGH THE LATE EVENING HOURS
AT ALL THE EAST COAST SITES. LATEST HRRR SHOWS MOST OF THE
LINGERING SHRAS EXITING THE AREA OVER THE NEXT FEW HOURS.
GRADUALLY TRENDED WINDS DOWN THROUGH THE PERIOD. UNDERCUT LAMP
GUIDANCE QUITE A BIT AS THEY STILL SEEM TO BE TOO HIGH.
&&
.PREV DISCUSSION... /ISSUED 718 PM EDT FRI OCT 26 2012/
UPDATE...
AS THE WINDS ACROSS THE REGION CONTINUE TO SLOWLY SUBSIDE...THE TROPICAL
STORM WARNING WAS DROPPED EARLIER THIS EVENING FOR LAKE OKEECHOBEE
WITH A SMALL CRAFT ADVISORY IN EFFECT WITH WINDS ACROSS THE LAKE
REMAINING AROUND 20 TO 25 KNOTS SUSTAINED WITH HIGHER GUSTS TO
AROUND 35 KNOTS. SO THE ONLY AREAS REMAINING UNDER TROPICAL STORM
WARNING ARE THE ATLANTIC WATERS TO THE EAST OF PALM BEACH COUNTY
AND THE PALM BEACH COUNTY COASTAL ZONE. THE CURRENT FORECAST
PACKAGE IS ON TRACK INDICATING CHANCES OF PRECIPITATION AND GUSTY
WINDS OVER NIGHT FROM THE OUTER PERIPHERY OF HURRICANE SANDY. WINDS
ACROSS THE REGION ARE FORECAST TO START SLOWLY SUBSIDING AS
HURRICANE SANDY CONTINUES ON A NORTHERLY TRACK THIS EVENING AND
OVER NIGHT.
60
PREV DISCUSSION... /ISSUED 245 PM EDT FRI OCT 26 2012/
DISCUSSION...HURRICANE SANDY CONTINUES TO SLOWLY DRIFT NORTH
OVER THE FAR NORTHERN BAHAMAS. ITS SLOW MOVEMENT WILL CONTINUE TO
ALLOW FOR THE OUTER BANDS TO MOVE ACROSS THE EASTERN PORTIONS OF
SOUTH FLORIDA THROUGH THIS EVENING. HOWEVER, THE WIND FIELD HAS
NOT EXPANDED TO THE EXTENT THAT SOME OF THE MODELS WERE EARLIER
INDICATING SO TROPICAL STORM WARNINGS WERE DISCONTINUED FOR
COASTAL BROWARD AND MIAMI-DADE COUNTIES AND THE ADJACENT ATLANTIC
WATERS INCLUDING BISCAYNE BAY. TROPICAL STORM CONDITIONS WILL
REMAIN POSSIBLE IN THE HEAVIER BANDS ACROSS COASTAL REGIONS OF
PALM BEACH COUNTY. FOR BROWARD AND MIAMI-DADE COUNTIES, THE
WARNING WAS REPLACED WITH A WIND ADVISORY ALONG WITH HIGH SURF
ADVISORY AND THE MENTION OF HIGH RISK OF RIP CURRENTS.
AFTER TONIGHT, A MID LEVEL TROUGH WILL BE DEEPENING ACROSS CENTRAL
NORTH AMERICA THROUGH SATURDAY AND SANDY WILL BEGIN TO ACCELERATE
NORTHEAST AWAY FROM THE FLORIDA PENINSULA WITH MUCH DRIER CONDITIONS
FILTERING INTO THE REGION AND CLEARING SKY CONDITIONS. AT THIS
POINT, A POWERFUL TROUGH WILL BE EVOLVING OVER THE NEXT SEVERAL DAYS
ACROSS THE EASTERN U.S. AND THIS WILL SET THE STAGE TO BRING THE
FIRST SIGNIFICANT SURGE OF COOLER AND DRIER AIR FOR THE FALL SEASON
ACROSS SOUTH FLORIDA ARRIVING ON MONDAY. BY TUESDAY AND WEDNESDAY
MORNINGS, TEMPERATURES WILL BE NEARLY 10 DEGREES BELOW THE AVERAGE
FOR LATE OCTOBER. MINIMUM TEMPERATURES WILL RANGE THOSE MORNINGS
FROM AROUND 50 TO THE WEST OF LAKE OKEECHOBEE AND THE MID TO UPPER
50S ALONG BOTH COASTAL METRO AREAS EXCEPT AROUND 60 ALONG THE
ATLANTIC COAST.
MARINE...THE WIND OVER THE CWA WATERS TODAY WILL SWING FROM A
NORTHERLY DIRECTION TO A NORTHWEST DIRECTION...AND REMAIN
NORTHWEST DIRECTION TONIGHT INTO THIS WEEKEND. THE WIND SPEEDS
WILL BE AT LEAST 25 TO 30 MPH MOST OF THE CWA WATERS TODAY...WITH
EVEN GUSTS UP TO TROPICAL STORM CONDITIONS OVER THE PALM BEACH
ATLANTIC WATERS AND LAKE OKEECHOBEE. THE WIND SPEEDS WILL REMAIN
NEARLY STEADY TONIGHT OVER ALL OF THE CWA WATERS...WITH GUSTS TO
TROPICAL STORM CONDITIONS OVER MOST OF THE CWA WATERS. SO WILL
CONTINUE THE TROPICAL STORM WARNING FOR THE NORTHERN WATERS INTO
TONIGHT...EXCEPT FOR A SCA ADVISORY FOR THE GULF WATERS WITH A
GALE WATCH FOR TONIGHT.
FIRE WEATHER...DRIER AIR WILL FILTER DOWN THE PENINSULA OVER THE
WEEKEND BUT RH VALUES WILL REMAIN ABOVE CRITICAL LEVELS THROUGH SUNDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 72 83 69 82 / 50 10 - -
FORT LAUDERDALE 71 84 69 83 / 40 10 - -
MIAMI 72 85 70 83 / 30 10 - -
NAPLES 72 84 70 81 / 10 - - -
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...WIND ADVISORY UNTIL 11 PM EDT THIS EVENING FOR COASTAL BROWARD-
COASTAL COLLIER-COASTAL MIAMI DADE-FAR SOUTH MIAMI DADE-
GLADES-HENDRY-INLAND BROWARD-INLAND COLLIER-INLAND MIAMI
DADE-INLAND PALM BEACH-MAINLAND MONROE-METRO BROWARD-METRO
MIAMI DADE-METRO PALM BEACH.
HIGH RIP CURRENT RISK THROUGH SUNDAY EVENING FOR COASTAL BROWARD-
COASTAL MIAMI DADE.
TROPICAL STORM WARNING FOR COASTAL PALM BEACH.
AM...SMALL CRAFT ADVISORY UNTIL 8 PM EDT SUNDAY FOR BISCAYNE BAY-
COASTAL WATERS FROM DEERFIELD BEACH TO OCEAN REEF, FL OUT
20 NM-WATERS FROM DEERFIELD BEACH TO OCEAN REEF, FL
EXTENDING FROM 20 NM TO THE TERRITORIAL WATERS OF THE
BAHAMAS.
TROPICAL STORM WARNING FOR COASTAL WATERS FROM JUPITER INLET TO
DEERFIELD BEACH, FL OUT 20 NM-WATERS FROM JUPITER INLET TO
DEERFIELD BEACH, FL EXTENDING FROM 20 NM TO 60 NM.
SMALL CRAFT ADVISORY UNTIL 8 PM EDT SUNDAY FOR LAKE OKEECHOBEE.
GM...SMALL CRAFT ADVISORY UNTIL 8 PM EDT SUNDAY FOR COASTAL WATERS
FROM CHOKOLOSKEE TO BONITA BEACH, FL OUT 20 NM-COASTAL
WATERS FROM EAST CAPE SABLE TO CHOKOLOSKEE, FL OUT 20 NM-
GULF WATERS FROM CHOKOLOSKEE TO BONITA BEACH, FL EXTENDING
FROM 20 TO 60 NM.
&&
$$
DISCUSSION/MARINE/FIRE...60/BD
AVIATION/RADAR...10/CD
AREA FORECAST DISCUSSION
NWS JACKSONVILLE FL
252 PM EDT THU OCT 25 2012
.SHORT TERM...HURRICANE SANDY CONTINUES TO PLOW THROUGH THE BAHAMAS
STILL AT CATEGORY 2 WITH 105 MPH MAX SUSTAINED WINDS. BROAD E TO
NE FLOW CONTINUES TO PROVIDE A FEED OF MOSTLY LOW LEVEL MOISTURE INTO
THE AREA WITH A FEW SHOWERS BEGINNING TO IMPACT FLAGLER COUNTY.
PWATS ARE ABOUT 1.2 TO 1.3 INCHES PER RAP MODEL AND BLENDED TOTAL
PRECIP WATER...AND WATER VAPOR IMAGERY STILL SHOWS DRIER AIR IN
THE MID AND UPPER LEVELS.
FOR TONIGHT...SIMILAR TO LAST NIGHT BREEZY/WINDY E TO NE WINDS CAN BE
EXPECTED IN THE EVENING AND TAPER OFF OVERNIGHT. WILL ALLOW THE LAKE
WIND ADVISORY FOR THE GA COAST TO END THIS EVENING. ELSEWHERE...T.S.
WATCH WILL BE CONTD AT THIS TIME. ISOLD TO POSSIBLY BRIEFLY SCT
SHOWER ACTIVITY CAN BE EXPECTED MAINLY FOR ERN ZONES. CURRENT MOS
GUIDANCE CONTINUES TO LOOK A BIT LOW PER RADAR IMAGERY. LOWS IN THE
LOWER TO MID 60S EXPECTED WITH NEAR 70 TEMPS NEAR THE COAST.
GUIDANCE SUGGESTS PATCHY FOG FOR WELL INLAND SE GA WHICH LOOKS
PLAUSIBLE GIVEN THE HIGHER DEWPOINT AIR AND DRY CONDITIONS ALOFT AND
WINDS MAY RELAX TO ABOUT 3-5 MPH UP THERE.
FRIDAY...STRONG NELY WINDS EXPECTED AS SANDY TRANSLATES NWD TO THE
NRN BAHAMAS AND STRENGTHENS THE PRES GRADIENT. WINDS OF 25-35 MPH
POSSIBLE WITH GUSTS NEAR 40-45 MPH POSSIBLE. THESE WINDS WILL BE
MORE POSSIBLE NEARER TO THE COAST. SOME BANDS OF COASTAL SHOWERS ARE
ANTICIPATED EARLY AND INCREASING RAIN CHANCES ARE EXPECTED FROM SE
TO NW AS MOISTURE INCREASES FROM THAT DIRECTION. ISOLD EMBEDDED
TSTMS ARE ANTICIPATED OVER THE SE ZONES AND COASTAL WATERS AND MAY
PRODUCE STRONGER WIND GUSTS IN PERIODS OF RAIN. FRI NIGHT...SANDY
WILL BE AT POINT OF CLOSEST APPROACH AS THE NHC JOGS THE SYSTEM A
BIT NNW. THE SYSTEM IS THEN PROJECTED TO LIFT N AND THEN NNE LATE.
WINDY CONDITIONS ARE EXPECTED ALONG THE COASTAL COUNTIES. ELEVATED
RAIN CHANCES EXPECTED BUT MAINLY IN THE CHANCE CATEGORY OVER THE SE
1/3RD OF THE CWA. SOME TSTM POTENTIAL STILL POSSIBLE E ZONES/MARINE
ZONES. SUSTAINED WINDS NEAR 25-35 MPH POSSIBLE ALONG THE COASTAL
AREAS FROM FERNANDINA TO FLAGLER BEACH. LOWS IN THE 60S EXPECTED.
SATURDAY...SANDY IS EXPECTED TO LIFT NEWD AT A FASTER CLIP BUT
BANDS OF SHOWERS ARE STILL ANTICIPATED AT THIS TIME OVER THE ERN
ZONES WITH WINDY CONDITIONS PREVAILING. SOME GLARING DIFFERENCES IN
MODEL WINDS AT 850 MB AND GFS IS THE MODEL OF CHOICE HERE. RAIN
CHANCES ARE EXPECTED TO DIMINISH THROUGH THE AFTN AND EARLY
EVENING AS DEEP MOISTURE AROUND THE SYSTEM MOVES OUT TO SEA. TSTM
POTENTIAL LOOKS TOO LOW TO MENTION AT THIS TIME. HIGHS IN THE 70S
TO NEAR 80. SAT NIGHT TO SUNDAY...COOLER AND DRIER CONDITIONS EXPECTED
AS THE SYSTEM PULLS AWAY WITH DEEP NW FLOW ANTICIPATED. LOWS IN
THE 50S EXPECTED AREA WIDE. HIGHS IN THE 70S ON SUNDAY.
.LONG TERM...MONDAY-THURSDAY.
MUCH COOLER AND DRIER NW FLOW EXPECTED FOR MOST OF THE TIME PERIOD
AS WEAK SFC HIGH PRESSURE BUILDS INTO THE REGION. SOME TROUGHING
WILL BE POSSIBLE BY MID WEEK AND MAY SUPPORT LOW END RAIN CHANCES
NEAR 20%. TEMPERATURES WILL BE AT OR BELOW NORMAL DURING THE EXTENDED
FORECAST.
&&
.AVIATION...MAINLY VFR CONDS WITH OCNL CIGS 3500-5000 FT. ISOLATED
COASTAL SHOWERS WILL CONTINUE TO MOVE INLAND AND HAVE VCSH AT ALL
TERMINALS.
&&
.MARINE...WILL CONTINUE WITH THE TROPICAL STORM WARNING FOR
THE COASTAL WATERS. WINDS AND SEAS WILL CONTINUE TO INCREASE
AS THE GRADIENT TIGHTENS BETWEEN HURRICANE SANDY AND HIGH PRESSURE
TO THE NORTH. EXPECTING TROPICAL STORM CONDITIONS BY LATE TONIGHT
INTO SATURDAY NIGHT WITH CONDITIONS BEGINNING TO IMPROVE
SUNDAY.
RIP CURRENTS/SURF: HIGH RISK OF DANGEROUS RIP CURRENTS WILL
CONTINUE INTO THE WEEKEND. BREAKER HEIGHTS WILL INCREASE TO
8 TO 12 FEET FRIDAY INTO THE WEEKEND. HAVE ISSUED A HIGH
SURF ADVISORY BEGINNING TONIGHT INTO SUNDAY MORNING.
MINOR TO MODERATE COASTAL FLOODING IS POSSIBLE DURING HIGH
TIDES ON FRIDAY AND SATURDAY AND A COASTAL FLOOD ADVISORY
MAY BE NEEDED.
&&
.PRELIMINARY POINT TEMPS/POPS...
AMG 62 82 61 77 / 10 10 10 10
SSI 69 78 67 75 / 20 20 50 50
JAX 68 81 64 76 / 20 20 40 40
SGJ 74 83 70 76 / 20 40 60 50
GNV 65 82 64 78 / 10 10 30 20
OCF 68 83 65 79 / 10 20 30 30
&&
.JAX WATCHES/WARNINGS/ADVISORIES...
FL...LAKE WIND ADVISORY UNTIL 6 PM EDT THIS EVENING FOR CLAY-MARION-
PUTNAM.
TROPICAL STORM WATCH FOR DUVAL-FLAGLER-NASSAU-ST JOHNS.
GA...HIGH RIP CURRENT RISK THROUGH SUNDAY EVENING FOR COASTAL CAMDEN-
COASTAL GLYNN.
LAKE WIND ADVISORY UNTIL 6 AM EDT FRIDAY FOR COASTAL CAMDEN-
COASTAL GLYNN.
HIGH SURF ADVISORY FROM 2 AM FRIDAY TO 6 AM EDT SUNDAY FOR
COASTAL CAMDEN-COASTAL GLYNN.
AM...TROPICAL STORM WARNING FOR ALTAMAHA SOUND GA TO FERNANDINA BEACH
FL 20 NM TO 60 NM OFFSHORE-ALTAMAHA SOUND GA TO FERNANDINA
BEACH FL OUT 20 NM-FERNANDINA BEACH TO ST AUGUSTINE FL 20
NM TO 60 NM OFFSHORE-FERNANDINA BEACH TO ST AUGUSTINE FL
OUT 20 NM-ST AUGUSTINE TO FLAGLER BEACH FL 20 NM TO 60 NM
OFFSHORE-ST AUGUSTINE TO FLAGLER BEACH FL OUT 20 NM.
&&
$$
SHASHY/PETERSON/WALKER
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
1027 PM EDT FRI OCT 26 2012
.SYNOPSIS...
HURRICANE SANDY WILL MOVE NORTHWARD OFF THE ATLANTIC COAST SATURDAY
AND SUNDAY. A STRONG PRESSURE GRADIENT WILL DEVELOP SATURDAY AND
CONTINUE THROUGH SUNDAY AS THE STORM MOVES NORTHWARD OFFSHORE.
THIS WILL CAUSE WINDY CONDITIONS SATURDAY AND SUNDAY. MOST OF THE
RAIN WILL BE CONFINED TO THE COASTAL REGION BUT THERE IS A SLIGHT
CHANCE OF SHOWERS MAKING IT INLAND AS FAR AS THE CENTRAL MIDLANDS
SATURDAY. A STRONG COLD FRONT WILL APPROACH FROM THE WEST SUNDAY
AND MOVE THROUGH SUNDAY NIGHT. THIS WILL BRING MUCH COLDER
TEMPERATURES TO THE AREA AS AN AREA OF COLD HIGH PRESSURE BUILDS
IN MONDAY THROUGH WEDNESDAY.
&&
.NEAR TERM /TONIGHT/...
A COLD FRONT WILL REMAIN TO THE WEST AS HURRICANE SANDY MOVES
NORTHWARD WELL OFFSHORE. AN INCREASING PRESSURE GRADIENT WILL HELP
TO INCREASE WINDS TO 10-15 MPH OVERNIGHT. ANY RAINFALL OVERNIGHT IS
EXPECTED TO REMAIN OFF TO THE EAST OF THE MIDLANDS AND CSRA...WITH
THE BULK OF IT REMAINING OFF THE ATLANTIC COAST. WILL STILL
INTRODUCE A SLIGHT CHANCE FOR RAINFALL ACROSS EXTREME EASTERN
AREAS TOWARDS MORNING. IT WILL BE ANOTHER WARM NIGHT WITH LOWS
MOSTLY IN THE LOWER 60S.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
THE AFFECTS OF SANDY TO THE EAST...WELL OFFSHORE...AND HIGHER
PRESSURE TO THE EAST WILL COMBINE TO CAUSE WINDS TO INCREASE TO 20
TO 30 MPH WITH GUSTS OVER 30 MPH AT TIMES SATURDAY THROUGH SUNDAY
NIGHT. MOST OF THE SHOWERS SHOULD REMAIN WELL TO THE EAST MAINLY
NEAR THE COAST BUT A WESTERN BAND OF SHOWERS COULD BRING A 20-30
PERCENT CHANCE OF SHOWERS TO THE CENTRAL MIDLANDS AND LOCATIONS TO
THE EAST. THE WESTERN PART INCLUDING THE CSRA LOOK TO BE RAIN
FREE. TEMPERATURES WILL NOT BE AS WARM SATURDAY AND SUNDAY MAINLY
DUE TO CLOUDS AND A CHANCE OF RAIN. HIGH TEMPERATURES WILL BE IN
THE LOWER TO MIDDLE 70S. THE COLD FRONT COMES THROUGH SUNDAY NIGHT
AND LOWS DROP INTO THE LOWER 40S.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
HURRICANE SANDY WILL BE GONE TO THE NORTH BY MONDAY AND
SHOULD HAVE TRANSITIONED INTO A MONSTER EXTRA-TROPICAL
STORM JUST IN TIME FOR HALLOWEEN. FORTUNATELY FOR SOUTH
CAROLINA...JUST COLD HIGH PRESSURE WILL MOVE ACROSS THE REGION.
TEMPERATURES WILL BE WELL BELOW NORMAL. HIGHS IN THE UPPER
50S TO LOWER 60S WITH LOWS IN THE MIDDLE TO UPPER 30S.
&&
.AVIATION /02Z SATURDAY THROUGH WEDNESDAY/...
SURFACE HIGH PRESSURE TO OUR NE...WITH HURRICANE SANDY WELL TO OUR
SOUTH OVER THE BAHAMAS. PRESSURE GRADIENT BETWEEN THE TWO PROVIDING
N TO NE WINDS. HIGH LEVEL CLOUDINESS ASSOCIATED WITH SANDY COVERING
MUCH OF OUR FA. SLOW MOVING COLD FRONT WELL TO OUR NW. SANDY IS
FORECAST TO MOVE TO THE N AND NE TONIGHT AND SATURDAY...WITH THE
BULK OF THE ASSOCIATED MOISTURE AND SHOWER ACTIVITY STAYING EAST OF
THE TERMINALS. GUIDANCE IN AGREEMENT INDICATING LOWER CLOUDINESS FOR
MUCH OF OUR FA LATE TONIGHT AND EARLY SATURDAY. LATEST SATELLITE AND
SURFACE OBS INDICATE LOWER CLOUDS CURRENTLY ACROSS PORTIONS OF
CENTRAL AND E NC...WITH MAINLY MVFR CIGS. LATEST RAP BRINGS LOWER
CLOUDS SW INTO OUR FA LATE TONIGHT UNDER A NE LOW LEVEL FLOW.
UNCERTAINTY WITH REGARDS TO WHETHER CIGS WILL BE MVFR OR IFR. FOR
NOW...WILL MAINTAIN LOW END MVFR CIGS. BREEZY CONDITIONS EXPECTED
SATURDAY.
EXTENDED AVIATION OUTLOOK...BREEZY CONDITIONS MAY CONTINUE THROUGH
MONDAY...OTHERWISE NO MAJOR RESTRICTIONS FOR AVIATION INTERESTS
EXPECTED.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...LAKE WIND ADVISORY FROM 10 AM SATURDAY TO 10 PM EDT SUNDAY FOR
SCZ015-016-018-020>022-025>031-035>038-041.
GA...LAKE WIND ADVISORY FROM 10 AM SATURDAY TO 10 PM EDT SUNDAY FOR
GAZ040-063>065-077.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
720 PM EDT FRI OCT 26 2012
.SYNOPSIS...
HURRICANE SANDY WILL MOVE NORTHWARD OFF THE ATLANTIC COAST SATURDAY
AND SUNDAY. A STRONG PRESSURE GRADIENT WILL DEVELOP SATURDAY AND
CONTINUE THROUGH SUNDAY AS THE STORM MOVES NORTHWARD OFFSHORE.
THIS WILL CAUSE WINDY CONDITIONS SATURDAY AND SUNDAY. MOST OF THE
RAIN WILL BE CONFINED TO THE COASTAL REGION BUT THERE IS A SLIGHT
CHANCE OF SHOWERS MAKING IT INLAND AS FAR AS THE CENTRAL MIDLANDS
SATURDAY. A STRONG COLD FRONT WILL APPROACH FROM THE WEST SUNDAY
AND MOVE THROUGH SUNDAY NIGHT. THIS WILL BRING MUCH COLDER
TEMPERATURES TO THE AREA AS AN AREA OF COLD HIGH PRESSURE BUILDS
IN MONDAY THROUGH WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
HIGH PRESSURE OVER THE AREA WILL WEAKEN TONIGHT. A COLD FRONT
WILL REMAIN TO THE WEST AS HURRICANE SANDY MOVES NORTHWARD WELL
OFFSHORE. AN INCREASING PRESSURE GRADIENT WILL HELP TO INCREASE
WINDS FROM 5-10 MPH TO 10-15 MPH AFTER MIDNIGHT. IT WILL BE
ANOTHER WARM NIGHT WITH LOWS MOSTLY IN THE LOWER 60S.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/...
THE AFFECTS OF SANDY TO THE EAST WELL OFFSHORE AND HIGHER
PRESSURE TO THE EAST WILL COMBINE TO CAUSE WINDS TO INCREASE TO 20
TO 30 MPH WITH GUSTS OVER 30 MPH AT TIMES SATURDAY THROUGH SUNDAY
NIGHT. MOST OF THE SHOWERS SHOULD REMAIN WELL TO THE EAST MAINLY
NEAR THE COAST BUT A WESTERN BAND OF SHOWERS COULD BRING A 20-30
PERCENT CHANCE OF SHOWERS TO THE CENTRAL MIDLANDS AND LOCATIONS TO
THE EAST. THE WESTERN PART INCLUDING THE CSRA LOOK TO BE RAIN
FREE. TEMPERATURES WILL NOT BE AS WARM SATURDAY AND SUNDAY MAINLY
DUE TO CLOUDS AND A CHANCE OF RAIN. HIGH TEMPERATURES WILL BE IN
THE LOWER TO MIDDLE 70S. THE COLD FRONT COMES THROUGH SUNDAY NIGHT
AND LOWS DROP INTO THE LOWER 40S.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
HURRICANE SANDY WILL BE GONE TO THE NORTH BY MONDAY AND
SHOULD HAVE TRANSITIONED INTO A MONSTER EXTRA-TROPICAL
STORM JUST IN TIME FOR HALLOWEEN. FORTUNATELY FOR SOUTH
CAROLINA...JUST COLD HIGH PRESSURE WILL MOVE ACROSS THE REGION.
TEMPERATURES WILL BE WELL BELOW NORMAL. HIGHS IN THE UPPER
50S TO LOWER 60S WITH LOWS IN THE MIDDLE TO UPPER 30S.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
SURFACE HIGH PRESSURE TO OUR NE...WITH HURRICANE SANDY WELL TO OUR
SOUTH OVER THE BAHAMAS. PRESSURE GRADIENT BETWEEN THE TWO PROVIDING
N TO NE WINDS. HIGH LEVEL CLOUDINESS ASSOCIATED WITH SANDY COVERING
MUCH OF OUR FA. SLOW MOVING COLD FRONT WELL TO OUR NW. SANDY IS
FORECAST TO MOVE TO THE N AND NE TONIGHT AND SATURDAY...WITH THE
BULK OF THE ASSOCIATED MOISTURE AND SHOWER ACTIVITY STAYING EAST OF
THE TERMINALS. GUIDANCE IN AGREEMENT INDICATING LOWER CLOUDINESS FOR
MUCH OF OUR FA LATE TONIGHT AND EARLY SATURDAY. LATEST SATELLITE AND
SURFACE OBS INDICATE LOWER CLOUDS CURRENTLY ACROSS PORTIONS OF
CENTRAL AND E NC...AND NE SC...WITH MVFR CIGS. LATEST RAP BRINGS
LOWER CLOUDS SW INTO OUR FA LATE TONIGHT UNDER A NE LOW LEVEL FLOW.
UNCERTAINTY WITH REGARDS TO WHETHER CIGS WILL BE MVFR OR IFR. FOR
NOW...WILL MAINTAIN LOW END MVFR CIGS. BREEZY CONDITIONS EXPECTED
SATURDAY.
EXTENDED AVIATION OUTLOOK...BREEZY CONDITIONS MAY CONTINUE THROUGH
MONDAY...OTHERWISE NO MAJOR RESTRICTIONS FOR AVIATION INTERESTS
EXPECTED.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...LAKE WIND ADVISORY FROM 10 AM SATURDAY TO 10 PM EDT SUNDAY FOR
SCZ015-016-018-020>022-025>031-035>038-041.
GA...LAKE WIND ADVISORY FROM 10 AM SATURDAY TO 10 PM EDT SUNDAY FOR
GAZ040-063>065-077.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
612 AM EDT THU OCT 25 2012
.SYNOPSIS...
DRY HIGH PRESSURE WILL REMAIN THE DOMINANT WEATHER FEATURE THROUGH
FRIDAY. TROPICAL SYSTEM SANDY IS FORECAST TO MOVE NORTHWARD AND
REMAIN OFF THE SOUTHEAST COAST THIS WEEKEND. SEE THE LATEST
ADVISORY FROM THE NATIONAL HURRICANE CENTER. A COLD FRONT
APPROACHING FROM THE WEST WILL MOVE THOUGH THE AREA SUNDAY. THE
COOLEST AIR OF THE SEASON SO FAR WILL FOLLOW THIS FRONT FOR
EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
LOW-LEVEL MOISTURE HAS INCREASED IN THE EASTERLY FLOW SOUTH OF THE
PRESSURE RIDGE. THIS MOISTURE COMBINED WITH STRONG RADIATIONAL
COOLING HAS RESULTED IN AREAS OF FOG. THE FOG MAY BECOME DENSE AND
A DENSE FOG ADVISORY MAY BE NEEDED ESPECIALLY IN THE EAST PART
WHERE DEW POINT TEMPERATURE ARE HIGHER. HEATING AND MIXING SHOULD
HELP DISSIPATE THE FOG BY 1000 AM. THE TEMPERATURE GUIDANCE IS
CLOSE. EXPECT HIGHS MAINLY IN THE LOWER 80S.
&&
.SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/...
SURFACE HIGH PRESSURE WILL REMAIN ENTRENCHED OVER THE REGION
THROUGH THURSDAY NIGHT. THE RIDGE WILL WEAKEN FRIDAY AHEAD OF THE
COLD FRONT APPROACHING FROM THE WEST AND TROPICAL SYSTEM SANDY
PUSHING NORTHWARD OFF THE SOUTHEAST COAST. MOISTURE SHOULD REMAIN
SHALLOW THROUGH FRIDAY. MOISTURE MAY BECOME DEEP ENOUGH TO SUPPORT
SHOWERS FRIDAY NIGHT IN THE EASTERLY FLOW BETWEEN SANDY OFF THE
SOUTHEAST COAST AND THE PRESSURE RIDGE TO THE NORTH. THE GFS IS
MORE PRONOUNCED WITH THIS MOISTURE COMPARED TO THE NAM. FORECASTED
CHANCE POPS IN THE EAST PART. USED THE GUIDANCE CONSENSUS FOR
THE TEMPERATURE FORECAST.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
THE MEDIUM RANGE MODELS SHOW TROPICAL CYCLONE SANDY MOVING
NORTHWARD AHEAD OF THE UPPER-LEVEL TROUGH MOVING INTO THE EASTERN
PART OF THE NATION. THE ECMWF HAS BEEN PERSISTENT IN ITS PATH
WHICH IS MORE WEST THAN THE OTHER MODELS BUT STILL KEEPS THE
CENTER WELL EAST OF THE FORECAST AREA.
THE COLD FRONT APPROACHING THE FORECAST AREA WILL BECOME DIFFUSE
BECAUSE OF THE NORTHERLY FLOW ASSOCIATED WITH THE CIRCULATION OF
SANDY. THE LACK OF CONVERGENCE INTO THE FRONT PLUS THE MODEL
FORECAST OF DEEPER MOISTURE ASSOCIATED WITH SANDY STAYING EAST OF
THE AREA SUPPORTS JUST LOW POPS. BREEZY NORTHERLY WINDS ARE
EXPECTED SATURDAY...ESPECIALLY ACROSS THE EASTERN MIDLANDS. THE
COOLEST AIR OF THE SEASON SO FAR WILL CIRCULATE INTO THE AREA
BEHIND THE COLD FRONT FOR EARLY NEXT WEEK. THE GFS ENSEMBLE MEANS
SUPPORT LOWS IN THE MIDDLE AND UPPER 30S.
&&
.AVIATION /10Z THURSDAY THROUGH MONDAY/...
NEAR SURFACE MOISTURE HAS CONTINUED TO INCREASE WITH DEWPOINTS IN
THE MID TO UPPER 50S. PATCHY FOG ALREADY DEVELOPING AGS/OGB WITH
IFR VSBYS. HI-RES HRRR AND SREF INDICATE REDUCED VSBYS SO HIGHER
THAN NORMAL CONFIDENCE IN RESTRICTIONS AT TERMINALS THROUGH THE
PREDAWN HOURS. IFR VSBYS TO DROP TO LIFR AFTER 08Z-09Z OGB/AGS
WHILE CAE/CUB START VFR AND DROP TO IFR AFTER 10Z WITH POSSIBLE
LIFR VSBYS AT TIMES BUT LOWER CONFIDENCE IN LIFR AT THIS TIME.
FOG SHOULD DISPERSE AFTER 15Z AS NORTHEAST-EASTERLY WINDS PICK UP
TO AROUND 10 MPH AND MIXING TAKES PLACE. SOME AFTERNOON CUMULUS
BUT NO RESTRICTIONS TO CIGS.
EXTENDED AVIATION OUTLOOK...INCREASING CONFIDENCE IN RESTRICTIONS
FRIDAY MORNING IN FOG AND STRATUS. INCREASING WINDS AND GUSTS
EXPECTED THIS WEEKEND ASSOCIATED WITH INCREASED PRESSURE GRADIENT
AS SANDY LIFTS NORTHWARD IN THE ATLANTIC.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
228 AM EDT THU OCT 25 2012
.SYNOPSIS...
DRY HIGH PRESSURE WILL REMAIN THE DOMINANT WEATHER FEATURE THROUGH
FRIDAY. TROPICAL SYSTEM SANDY IS FORECAST TO MOVE NORTHWARD AND
REMAIN OFF THE SOUTHEAST COAST THIS WEEKEND. SEE THE LATEST
ADVISORY FROM THE NATIONAL HURRICANE CENTER. A COLD FRONT
APPROACHING FROM THE WEST WILL MOVE THOUGH THE AREA SUNDAY. THE
COOLEST AIR OF THE SEASON SO FAR WILL FOLLOW THIS FRONT FOR
EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TODAY/...
LOW-LEVEL MOISTURE HAS INCREASED IN THE EASTERLY FLOW SOUTH OF THE
PRESSURE RIDGE. THIS MOISTURE COMBINED WITH STRONG RADIATIONAL
COOLING HAS RESULTED IN AREAS OF FOG. THE FOG MAY BECOME DENSE AND
A DENSE FOG ADVISORY MAY BE NEEDED ESPECIALLY IN THE EAST PART
WHERE DEW POINT TEMPERATURE ARE HIGHER. HEATING AND MIXING SHOULD
HELP DISSIPATE THE FOG BY 1000 AM. THE TEMPERATURE GUIDANCE IS
CLOSE. EXPECT HIGHS MAINLY IN THE LOWER 80S.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/...
SURFACE HIGH PRESSURE WILL REMAIN ENTRENCHED OVER THE REGION
THROUGH THURSDAY NIGHT. THE RIDGE WILL WEAKEN FRIDAY AHEAD OF THE
COLD FRONT APPROACHING FROM THE WEST AND TROPICAL SYSTEM SANDY
PUSHING NORTHWARD OFF THE SOUTHEAST COAST. MOISTURE SHOULD REMAIN
SHALLOW THROUGH FRIDAY. MOISTURE MAY BECOME DEEP ENOUGH TO SUPPORT
SHOWERS FRIDAY NIGHT IN THE EASTERLY FLOW BETWEEN SANDY OFF THE
SOUTHEAST COAST AND THE PRESSURE RIDGE TO THE NORTH. THE GFS IS
MORE PRONOUNCED WITH THIS MOISTURE COMPARED TO THE NAM. FORECASTED
CHANCE POPS IN THE EAST PART. USED THE GUIDANCE CONSENSUS FOR
THE TEMPERATURE FORECAST.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
THE MEDIUM RANGE MODELS SHOW TROPICAL CYCLONE SANDY MOVING
NORTHWARD AHEAD OF THE UPPER-LEVEL TROUGH MOVING INTO THE EASTERN
PART OF THE NATION. THE ECMWF HAS BEEN PERSISTENT IN ITS PATH
WHICH IS MORE WEST THAN THE OTHER MODELS BUT STILL KEEPS THE
CENTER WELL EAST OF THE FORECAST AREA.
THE COLD FRONT APPROACHING THE FORECAST AREA WILL BECOME DIFFUSE
BECAUSE OF THE NORTHERLY FLOW ASSOCIATED WITH THE CIRCULATION OF
SANDY. THE LACK OF CONVERGENCE INTO THE FRONT PLUS THE MODEL
FORECAST OF DEEPER MOISTURE ASSOCIATED WITH SANDY STAYING EAST OF
THE AREA SUPPORTS JUST LOW POPS. BREEZY NORTHERLY WINDS ARE
EXPECTED SATURDAY...ESPECIALLY ACROSS THE EASTERN MIDLANDS. THE
COOLEST AIR OF THE SEASON SO FAR WILL CIRCULATE INTO THE AREA
BEHIND THE COLD FRONT FOR EARLY NEXT WEEK. THE GFS ENSEMBLE MEANS
SUPPORT LOWS IN THE MIDDLE AND UPPER 30S.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
NEAR SURFACE MOISTURE HAS CONTINUED TO INCREASE WITH DEWPOINTS IN
THE MID TO UPPER 50S. PATCHY FOG ALREADY DEVELOPING AGS/OGB WITH
IFR VSBYS. HI-RES HRRR AND SREF INDICATE REDUCED VSBYS SO HIGHER
THAN NORMAL CONFIDENCE IN RESTRICTIONS AT TERMINALS THROUGH THE
PREDAWN HOURS. IFR VSBYS TO DROP TO LIFR AFTER 08Z-09Z OGB/AGS
WHILE CAE/CUB START VFR AND DROP TO IFR AFTER 10Z WITH POSSIBLE
LIFR VSBYS AT TIMES BUT LOWER CONFIDENCE IN LIFR AT THIS TIME.
FOG SHOULD DISPERSE AFTER 15Z AS NORTHEAST-EASTERLY WINDS PICK UP
TO AROUND 10 MPH AND MIXING TAKES PLACE. SOME AFTERNOON CUMULUS
BUT NO RESTRICTIONS TO CIGS.
EXTENDED AVIATION OUTLOOK...INCREASING CONFIDENCE IN RESTRICTIONS
FRIDAY MORNING IN FOG AND STRATUS. INCREASING WINDS AND GUSTS
EXPECTED THIS WEEKEND ASSOCIATED WITH INCREASED PRESSURE GRADIENT
AS SANDY LIFTS NORTHWARD IN THE ATLANTIC.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
521 PM CDT THU OCT 25 2012
.DISCUSSION...
336 PM CDT
PREVIOUS DISCUSSION...
1251 PM CDT
THIS UPDATE STILL VALID FOR REST OF AFTERNOON AND EARLY
EVENING...
NO BIG CHANGES IN OVERALL FORECAST THINKING THIS AFTERNOON. WE
DID SLOW FRONTAL TIMING SLIGHTLY...NOW EXPECT FRONT THROUGH THE
ROCKFORD AREA AROUND 4PM CDT AND ACROSS THE CHICAGO METRO BETWEEN
6PM AND 8PM DEPENDING ON YOUR LOCATION. LATEST RAP GUIDANCE
SUGGESTS 300-500 J/KG MUCAPE IMMEDIATELY ALONG THE FRONT WITH
50-60KT DEEP LAYER SHEAR. EXPECT CONVECTIVE COVERAGE TO INCREASE
ALONG THE FRONT OVER NEXT FEW HOURS AS A SHORTWAVE TROUGH BEGINS
TO LIFT NORTHEAST ACROSS IOWA EARLY THIS AFTERNOON. WITH INTENSE
SHEAR NOTED IMMEDIATELY ALONG AND JUST BEHIND THE FRONT...WILL
HAVE TO MONITOR FOR A MARGINAL SEVERE WEATHER THREAT THROUGH THE
AFTERNOON AND EARLY EVENING AS FAST MOVING THUNDERSTORMS ARE
EXPECTED TO DEVELOP.
BMD
DISCUSSION...LATE TONIGHT AND BEYOND...
300 PM CDT
SHARP COLD FRONT TO HAVE MOVED TO NORTH CENTRAL AND WEST CENTRAL
IN BY MIDNIGHT...WITH ONLY SOME LINGERING POST FRONTAL LIGHT
SHOWERS INTO THE OVERNIGHT HOURS FROM NORTHWEST IN TO E CENTRAL
IL. WITH THE FRONT AND THE POST FRONTAL SHOWERS HAVING MOVED EAST
OF THE LOCAL FORECAST AREA DURING THE PREDAWN HOURS THE CLEARING
SEEN UPSTREAM OVER SOUTHERN NE AND MUCH OF KS IS EXPECTED TO
SPREAD INTO NORTHWEST AND WEST CENTRAL IL BY LATE
EVENING...CONTINUING EASTWARD TO FAR NORTHEASTERN IL BY DAWN
FRIDAY.
THIS MORNING/S 12Z RAOBS SHOWED THAT BEHIND THE FRONT THAT COLD
AIR HAD PENETRATED AS FAR SOUTH AS SOUTHERN NE WITH KLBF
MEASURING AN 850 HPA TEMPERATURE OF -5C. THIS IS IN CONTRAST TO
+15C REPORTED AT BOTH KTOP AND KDVN. THIS AIR WAS COLD ENOUGH TO
SUPPORT SNOW THIS MORNING IN PARTS OF MN...IA AND NE.
WHILE THE FRONTAL PASSAGE SHIFTS LOW LEVEL WINDS TO OUT OF THE
NORTH-NORTHWEST AND NORTHWEST AND DROPS SURFACE TEMPERATURES
SIGNIFICANTLY TONIGHT...THE FLOW LOCALLY 850 AND 800 HPA IS
EXPECTED TO BACK TO WEST AND THE SOUTHWEST AT INCREASING HEIGHTS.
THIS IS IN RESPONSE TO THERE ONLY VERY SLIGHT MID AND UPPER
VEERING OF THE FLOW INDICATED DUE TO ANOTHER STRONG JET MAX AND
SHORT WAVE TROUGH TO ROTATE NORTHEASTWARD FROM THEE CENTRAL
PLAINS TO THE UPPER MIDWEST DURING THE NIGHT. THIS WEST TO
SOUTHWEST FLOW ABOVE THE BOUNDARY LAYER KEEPS THE COOL AIR
OVER THE LOCAL AREA RATHER SHALLOW AND ANY PRECIPITATION
LINGERING INTO THE NIGHT IS EXPECTED TO REMAIN LIQUID...ENDING
BEFORE THE COLD AIR DEEPENS WITH THE PASSAGE OF THE UPSTREAM
SHORT WAVE.
WITH 850 HPA TEMPERATURE PROGS AVERAGING ABOUT +1 TO -2C OVER THE
FORECAST AREA DURING THE DAY FRIDAY AFTERNOON TEMPERATURES SHOULD
ONLY RECOVER TO UPPER 40S AND LOWER 50S IN THE AFTERNOON. ANOTHER
SHORT WAVE TO MOVE ACROSS THE REGION LATE FRIDAY NIGHT AND EARLY
SATURDAY REINFORCES THE LOW LEVEL COLD AIR...WHICH IS EXPECTED TO
LIMIT MAX TEMPS FOR SATURDAY TO GENERALLY THE 45-50 DEG F
RANGE...WITH SIMILAR HIGHS FOR SUNDAY AND MONDAY.
NORTHWEST WINDS GRADUALLY VEER TO NORTH FRIDAY NIGHT AND
NORTH-NORTHEAST SATURDAY BEFORE BACKING A BIT TO NORTH DURING
SUNDAY AND INTO MONDAY. WHILE TEMPERATURE DIFFERENTIAL BETWEEN
THE LAKE AND THE COLD LOW LEVEL AIR IS SUFFICIENT FOR LAKE EFFECT
INITIATION PER MODEL FORECAST TEMPERATURE PROFILES ANY
SIGNIFICANTLY VERTICAL GROWTH IS TO BE CAPPED BY AN OVERLYING
INVERSION. THUS...ONLY EXPECT SOME LAKE EFFECT CLOUDS SATURDAY
NIGHT AND SUNDAY NEAR THE LAKE AND INLAND TO THE KANKAKEE RIVER
VALLEY OF NORTHWEST IN AND FAR NORTHEAST IL...ALONG AND NEAR THE
IL-IN STATE LINE. BY SUNDAY NIGHT THIS INVERSION LESSENED AND
EVENTUALLY ELIMINATED ALLOWING A SMALL CHANCE OF LAKE EFFECT SNOW
AND RAIN SHOWERS SUNDAY NIGHT INTO MONDAY NIGHT.
HOW LONG THE REGION REMAINS UNDER DEEP NORTH TO NORTHWEST FLOW
AND THE VERY COOL AIR MASS DEPENDS ON HOW THE HURRICANE SANDY
INTERACTS WITH THE UPPER TROUGH TO BE LOCATED FROM WESTERN HUDSON
BAY ACROSS ONTARIO AND THE UPPER GREAT LAKES MONDAY. MODELS IN
PRETTY GOOD AGREEMENT IN TURNING SANDY NORTH-NORTHWESTWARD TO
OVER THE MID ATLANTIC AND SOUTHERN NEW ENGLAND COASTS LATE
TUESDAY AND TUESDAY NIGHT. MODELS THEN CONTINUE TO MOVE THE
EXTRA- TROPICAL SYSTEM NORTH-NORTHWEST OVER THE LOWER GREAT LAKES
DURING LATER TUESDAY AND TUESDAY NIGHT...AND TO FAR SOUTHERN
QUEBEC BY THURSDAY MORNING. THIS SUGGESTS THAT THE VERY COOL AIR
MASS WILL BE LOCKED IN PLACE OVER THE REGION UNTIL AT LEAST LATE
INTO NEXT WEEK KEEPING THE STRING OF BELOW NORMAL TEMPERATURE
CONDITIONS GOING.
SOME INDICATION THAT AS THE SYSTEM MOVES TO THE LOWER GREAT LAKES
AND SOUTHERN QUEBEC THAT MOISTURE WILL BE WRAPPED WEST AND
SOUTHWESTWARD TO THE UPPER GREAT LAKES FOR LATER TUESDAY AND
WEDNESDAY WHICH BRINGS A SLIGHT CHANCE RAIN OR RAIN AND SNOW
ALMOST TO THE WESTERN SHORE OF LAKE MI. HAVE SLIGHT CHANCES INTO
NORTHWEST IN WHILE HAVE KEPT NORTHEAST IL BELOW THE SLIGHT CHANCE
POP THRESHOLD AS WAY TOO MUCH UNCERTAINTY AT THIS POINT.
TRS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 22Z...
* WIND SHIFT TO WEST IMMINENT
* SHOWERS ALONG AND MAINLY BEHIND A COLD FRONT...WITH SCATTERED
THUNDERSTORMS ALSO POSSIBLE.
* MVFR/IFR CIGS IMMEDIATELY BEHIND THE COLD FRONT.
IZZI
//DISCUSSION...UPDATED 18Z...
A STRONG COLD FRONT IS BEGINNING TO PUSH INTO NORTHWESTERN ILLINOIS
EARLY THIS AFTERNOON. AHEAD OF THE FRONT...BKN STRATUS DECK AROUND
040 HAS OVERSPREAD MOST OF THE NORTHERN ILLINOIS TERMINALS WITH SSW
WINDS GUSTING AROUND 30KT. EXPECT LITTLE TO CHANGE OVER THE NEXT
SEVERAL HOURS AHEAD OF THE FRONT EXCEPT FOR SOME LOWING OF CIGS TO
020-025. BASED ON FAIRLY GOOD AGREEMENT BETWEEN VARIOUS HOURLY
MODELS AND A RADAR FIX ON THE COLD FRONT...HAVE FAIRLY HIGH
CONFIDENCE IN FRONTAL TIMING LATE THIS AFTERNOON AND EARLY EVENING.
DID BUMP BACK TIMING SLIGHTLY WITH THE 18Z ISSUANCE TO MATCH LATEST
THINKING. A LITTLE LESS CERTAIN ARE THE CONVECTIVE CHANCES WITH THIS
SYSTEM. THERE IS MODEST INSTABILITY ALONG THE FRONT WITH STRONG
FORCING AND SUSPECT THAT SCT/BKN LINE TSRA WILL CONTINUE TO DEVELOP
ALONG THE FRONT THIS AFTERNOON. NOT SURE AT THIS POINT HOW EXTENSIVE
THE COVERAGE MAY BECOME SO WILL STICK WITH VCTS FOR NOW.
IMMEDIATELY BEHIND THE FRONT...EXPECT CONDITIONS TO RAPIDLY
DETERIORATE. RAIN WILL OVERSPREAD THE AREA WITH THE THREAT FOR SOME
EMBEDDED THUNDERSTORMS CONTINUING FOR AN HOUR OR SO AFTER FROPA.
EXPECT CIGS TO QUICKLY FALL INTO LOW END MVFR AND IFR CATEGORY...AND
STILL CANNOT RULE OUT LIFR...THOUGH ONLY NAM SOUNDINGS ARE
STRONGLY IN FAVOR OF THIS. WINDS WILL SHIFT TO THE NORTHWEST AND
THERE MAY BE A SHORT PERIOD WHERE WIND GUSTS IN EXCESS OF 30 KT
ARE POSSIBLE AS A STRONG AIR OF PRESSURE RISES MOVES ACROSS THE
TERMINALS. OVERNIGHT...EXPECT CONDITIONS TO GRADUALLY IMPROVE BACK
TO MVFR...THEN VFR WITH WINDS DIMINISHING AS HIGH PRESSURE BUILDS
IN FROM THE WEST. VFR CONDITIONS SHOULD CONTINUE WITH MODERATE
NORTHWEST WINDS AROUND 12 KT AND OCCASIONAL GUSTS ON FRIDAY. BMD
//ORD AND MDW CONFIDENCE...UPDATED 22Z...
* HIGH CONFIDENCE IN WIND DIRECTION/SPEEDS THROUGH THIS EVENING.
MEDIUM CONFIDENCE IN SPEEDS OVERNIGHT AND FRIDAY.
* HIGH CONFIDENCE IN FROPA/PRECIP TIMING.
* HIGH CONFIDENCE IN CIGS DROPPING BELOW 015...MEDIUM CONFIDENCE
IN DROPPING BELOW 010.
IZZI
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
* FRIDAY NIGHT THROUGH MONDAY...PREDOMINANTLY VFR. SMALL THREAT OF
LOCALIZED LAKE EFFECT MVFR CIGS AND SLIGHT CHANCE OF SHRA.
* TUESDAY AND WEDNESDAY...VFR.
&&
.MARINE...
347 AM...THE GRADIENT WILL CONTINUE TO TIGHTEN THIS MORNING AS
LOW LEVEL WINDS STRENGTHEN AHEAD OF AN APPROACHING COLD FRONT.
ALREADY HAD A SHIP WEST OF BEAVER ISLAND OF 32 KTS AT 07Z.
CONTINUED THE OCCASIONAL GALE GUST WORDING BUT DESPITE A VERY
STRONG MARINE LAYER/INVERSION...ITS POSSIBLE THAT MORE PREVAILING
GALES MAY DEVELOP LATER THIS MORNING AND CONTINUE THIS
AFTERNOON...MAINLY OVER THE NORTHERN THIRD/HALF OF THE LAKE. THIS
WILL NEED TO BE MONITORED FOR A POSSIBLE GALE WARNING. THE COLD
FRONT WILL MOVE ACROSS THE LAKE LATE THIS AFTERNOON INTO EARLY
THIS EVENING... SHIFTING WINDS TO THE NORTHWEST AND STRONG GUSTS
MAY ACCOMPANY THE PASSAGE OF THE FRONT. NORTHWEST WINDS WILL
SLOWLY DIMINISH TO 15-25 KTS FRIDAY AS HIGH PRESSURE BUILDS ACROSS
THE PLAINS. THIS HIGH WILL SPREAD EAST ACROSS THE WESTERN LAKES
FRIDAY NIGHT INTO SATURDAY WITH WINDS DIMINISHING FURTHER BUT THE
HIGH THEN BECOMES STATIONARY ACROSS THE WESTERN LAKES AS THE
STRONG REMNANTS OF SANDY MOVE NORTH ALONG THE EAST COAST SUNDAY
AND MONDAY. THERE REMAINS QUITE A BIT OF UNCERTAINTY EARLY/MID
NEXT WEEK BUT IF CURRENT TRENDS CONTINUE...THERE COULD BE A
PROLONGED PERIOD OF NORTHERLY WINDS. CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
LMZ669-LMZ868-LMZ870 UNTIL 10 PM THURSDAY
SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 10 PM SATURDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
339 PM CDT THU OCT 25 2012
.DISCUSSION...
336 PM CDT
PREVIOUS DISCUSSION...
1251 PM CDT
THIS UPDATE STILL VALID FOR REST OF AFTERNOON AND EARLY
EVENING...
NO BIG CHANGES IN OVERALL FORECAST THINKING THIS AFTERNOON. WE
DID SLOW FRONTAL TIMING SLIGHTLY...NOW EXPECT FRONT THROUGH THE
ROCKFORD AREA AROUND 4PM CDT AND ACROSS THE CHICAGO METRO BETWEEN
6PM AND 8PM DEPENDING ON YOUR LOCATION. LATEST RAP GUIDANCE
SUGGESTS 300-500 J/KG MUCAPE IMMEDIATELY ALONG THE FRONT WITH
50-60KT DEEP LAYER SHEAR. EXPECT CONVECTIVE COVERAGE TO INCREASE
ALONG THE FRONT OVER NEXT FEW HOURS AS A SHORTWAVE TROUGH BEGINS
TO LIFT NORTHEAST ACROSS IOWA EARLY THIS AFTERNOON. WITH INTENSE
SHEAR NOTED IMMEDIATELY ALONG AND JUST BEHIND THE FRONT...WILL
HAVE TO MONITOR FOR A MARGINAL SEVERE WEATHER THREAT THROUGH THE
AFTERNOON AND EARLY EVENING AS FAST MOVING THUNDERSTORMS ARE
EXPECTED TO DEVELOP.
BMD
DISCUSSION...LATE TONIGHT AND BEYOND...
300 PM CDT
SHARP COLD FRONT TO HAVE MOVED TO NORTH CENTRAL AND WEST CENTRAL
IN BY MIDNIGHT...WITH ONLY SOME LINGERING POST FRONTAL LIGHT
SHOWERS INTO THE OVERNIGHT HOURS FROM NORTHWEST IN TO E CENTRAL
IL. WITH THE FRONT AND THE POST FRONTAL SHOWERS HAVING MOVED EAST
OF THE LOCAL FORECAST AREA DURING THE PREDAWN HOURS THE CLEARING
SEEN UPSTREAM OVER SOUTHERN NE AND MUCH OF KS IS EXPECTED TO
SPREAD INTO NORTHWEST AND WEST CENTRAL IL BY LATE
EVENING...CONTINUING EASTWARD TO FAR NORTHEASTERN IL BY DAWN
FRIDAY.
THIS MORNING/S 12Z RAOBS SHOWED THAT BEHIND THE FRONT THAT COLD
AIR HAD PENETRATED AS FAR SOUTH AS SOUTHERN NE WITH KLBF
MEASURING AN 850 HPA TEMPERATURE OF -5C. THIS IS IN CONTRAST TO
+15C REPORTED AT BOTH KTOP AND KDVN. THIS AIR WAS COLD ENOUGH TO
SUPPORT SNOW THIS MORNING IN PARTS OF MN...IA AND NE.
WHILE THE FRONTAL PASSAGE SHIFTS LOW LEVEL WINDS TO OUT OF THE
NORTH-NORTHWEST AND NORTHWEST AND DROPS SURFACE TEMPERATURES
SIGNIFICANTLY TONIGHT...THE FLOW LOCALLY 850 AND 800 HPA IS
EXPECTED TO BACK TO WEST AND THE SOUTHWEST AT INCREASING HEIGHTS.
THIS IS IN RESPONSE TO THERE ONLY VERY SLIGHT MID AND UPPER
VEERING OF THE FLOW INDICATED DUE TO ANOTHER STRONG JET MAX AND
SHORT WAVE TROUGH TO ROTATE NORTHEASTWARD FROM THEE CENTRAL
PLAINS TO THE UPPER MIDWEST DURING THE NIGHT. THIS WEST TO
SOUTHWEST FLOW ABOVE THE BOUNDARY LAYER KEEPS THE COOL AIR
OVER THE LOCAL AREA RATHER SHALLOW AND ANY PRECIPITATION
LINGERING INTO THE NIGHT IS EXPECTED TO REMAIN LIQUID...ENDING
BEFORE THE COLD AIR DEEPENS WITH THE PASSAGE OF THE UPSTREAM
SHORT WAVE.
WITH 850 HPA TEMPERATURE PROGS AVERAGING ABOUT +1 TO -2C OVER THE
FORECAST AREA DURING THE DAY FRIDAY AFTERNOON TEMPERATURES SHOULD
ONLY RECOVER TO UPPER 40S AND LOWER 50S IN THE AFTERNOON. ANOTHER
SHORT WAVE TO MOVE ACROSS THE REGION LATE FRIDAY NIGHT AND EARLY
SATURDAY REINFORCES THE LOW LEVEL COLD AIR...WHICH IS EXPECTED TO
LIMIT MAX TEMPS FOR SATURDAY TO GENERALLY THE 45-50 DEG F
RANGE...WITH SIMILAR HIGHS FOR SUNDAY AND MONDAY.
NORTHWEST WINDS GRADUALLY VEER TO NORTH FRIDAY NIGHT AND
NORTH-NORTHEAST SATURDAY BEFORE BACKING A BIT TO NORTH DURING
SUNDAY AND INTO MONDAY. WHILE TEMPERATURE DIFFERENTIAL BETWEEN
THE LAKE AND THE COLD LOW LEVEL AIR IS SUFFICIENT FOR LAKE EFFECT
INITIATION PER MODEL FORECAST TEMPERATURE PROFILES ANY
SIGNIFICANTLY VERTICAL GROWTH IS TO BE CAPPED BY AN OVERLYING
INVERSION. THUS...ONLY EXPECT SOME LAKE EFFECT CLOUDS SATURDAY
NIGHT AND SUNDAY NEAR THE LAKE AND INLAND TO THE KANKAKEE RIVER
VALLEY OF NORTHWEST IN AND FAR NORTHEAST IL...ALONG AND NEAR THE
IL-IN STATE LINE. BY SUNDAY NIGHT THIS INVERSION LESSENED AND
EVENTUALLY ELIMINATED ALLOWING A SMALL CHANCE OF LAKE EFFECT SNOW
AND RAIN SHOWERS SUNDAY NIGHT INTO MONDAY NIGHT.
HOW LONG THE REGION REMAINS UNDER DEEP NORTH TO NORTHWEST FLOW
AND THE VERY COOL AIR MASS DEPENDS ON HOW THE HURRICANE SANDY
INTERACTS WITH THE UPPER TROUGH TO BE LOCATED FROM WESTERN HUDSON
BAY ACROSS ONTARIO AND THE UPPER GREAT LAKES MONDAY. MODELS IN
PRETTY GOOD AGREEMENT IN TURNING SANDY NORTH-NORTHWESTWARD TO
OVER THE MID ATLANTIC AND SOUTHERN NEW ENGLAND COASTS LATE
TUESDAY AND TUESDAY NIGHT. MODELS THEN CONTINUE TO MOVE THE
EXTRA- TROPICAL SYSTEM NORTH-NORTHWEST OVER THE LOWER GREAT LAKES
DURING LATER TUESDAY AND TUESDAY NIGHT...AND TO FAR SOUTHERN
QUEBEC BY THURSDAY MORNING. THIS SUGGESTS THAT THE VERY COOL AIR
MASS WILL BE LOCKED IN PLACE OVER THE REGION UNTIL AT LEAST LATE
INTO NEXT WEEK KEEPING THE STRING OF BELOW NORMAL TEMPERATURE
CONDITIONS GOING.
SOME INDICATION THAT AS THE SYSTEM MOVES TO THE LOWER GREAT LAKES
AND SOUTHERN QUEBEC THAT MOISTURE WILL BE WRAPPED WEST AND
SOUTHWESTWARD TO THE UPPER GREAT LAKES FOR LATER TUESDAY AND
WEDNESDAY WHICH BRINGS A SLIGHT CHANCE RAIN OR RAIN AND SNOW
ALMOST TO THE WESTERN SHORE OF LAKE MI. HAVE SLIGHT CHANCES INTO
NORTHWEST IN WHILE HAVE KEPT NORTHEAST IL BELOW THE SLIGHT CHANCE
POP THRESHOLD AS WAY TOO MUCH UNCERTAINTY AT THIS POINT.
TRS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* SOUTH WINDS GUSTING TO NEAR 30 KT BECOMING NORTHWEST LATE THIS
AFTERNOON. A BRIEF PERIOD OF STRONGER THAN 30KT NW WINDS ARE
POSSIBLE IMMEDIATELY BEHIND THE FRONT...BUT THEN SUBSIDING
THEREAFTER.
* SHOWERS ALONG AND MAINLY BEHIND A COLD FRONT...WITH SCATTERED
THUNDERSTORMS ALSO POSSIBLE.
* MVFR/IFR CIGS IMMEDIATELY BEHIND THE COLD FRONT. BMD
//DISCUSSION...UPDATED 18Z...
A STRONG COLD FRONT IS BEGINNING TO PUSH INTO NORTHWESTERN ILLINOIS
EARLY THIS AFTERNOON. AHEAD OF THE FRONT...BKN STRATUS DECK AROUND
040 HAS OVERSPREAD MOST OF THE NORTHERN ILLINOIS TERMINALS WITH SSW
WINDS GUSTING AROUND 30KT. EXPECT LITTLE TO CHANGE OVER THE NEXT
SEVERAL HOURS AHEAD OF THE FRONT EXCEPT FOR SOME LOWING OF CIGS TO
020-025. BASED ON FAIRLY GOOD AGREEMENT BETWEEN VARIOUS HOURLY
MODELS AND A RADAR FIX ON THE COLD FRONT...HAVE FAIRLY HIGH
CONFIDENCE IN FRONTAL TIMING LATE THIS AFTERNOON AND EARLY EVENING.
DID BUMP BACK TIMING SLIGHTLY WITH THE 18Z ISSUANCE TO MATCH LATEST
THINKING. A LITTLE LESS CERTAIN ARE THE CONVECTIVE CHANCES WITH THIS
SYSTEM. THERE IS MODEST INSTABILITY ALONG THE FRONT WITH STRONG
FORCING AND SUSPECT THAT SCT/BKN LINE TSRA WILL CONTINUE TO DEVELOP
ALONG THE FRONT THIS AFTERNOON. NOT SURE AT THIS POINT HOW EXTENSIVE
THE COVERAGE MAY BECOME SO WILL STICK WITH VCTS FOR NOW.
IMMEDIATELY BEHIND THE FRONT...EXPECT CONDITIONS TO RAPIDLY
DETERIORATE. RAIN WILL OVERSPREAD THE AREA WITH THE THREAT FOR SOME
EMBEDDED THUNDERSTORMS CONTINUING FOR AN HOUR OR SO AFTER FROPA.
EXPECT CIGS TO QUICKLY FALL INTO LOW END MVFR AND IFR CATEGORY...AND
STILL CANNOT RULE OUT LIFR...THOUGH ONLY NAM SOUNDINGS ARE
STRONGLY IN FAVOR OF THIS. WINDS WILL SHIFT TO THE NORTHWEST AND
THERE MAY BE A SHORT PERIOD WHERE WIND GUSTS IN EXCESS OF 30 KT
ARE POSSIBLE AS A STRONG AIR OF PRESSURE RISES MOVES ACROSS THE
TERMINALS. OVERNIGHT...EXPECT CONDITIONS TO GRADUALLY IMPROVE BACK
TO MVFR...THEN VFR WITH WINDS DIMINISHING AS HIGH PRESSURE BUILDS
IN FROM THE WEST. VFR CONDITIONS SHOULD CONTINUE WITH MODERATE
NORTHWEST WINDS AROUND 12 KT AND OCCASIONAL GUSTS ON FRIDAY. BMD
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE IN WIND DIRECTION/SPEEDS THROUGH THIS EVENING.
MEDIUM CONFIDENCE IN SPEEDS OVERNIGHT AND FRIDAY.
* HIGH CONFIDENCE IN FROPA/PRECIP TIMING.
* HIGH CONFIDENCE IN CIGS DROPPING BELOW 015...MEDIUM CONFIDENCE
IN DROPPING BELOW 010. BMD
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
* FRIDAY NIGHT THROUGH MONDAY...PREDOMINANTLY VFR. SMALL THREAT OF
LOCALIZED LAKE EFFECT MVFR CIGS AND SLIGHT CHANCE OF SHRA.
* TUESDAY AND WEDNESDAY...VFR.
&&
.MARINE...
347 AM...THE GRADIENT WILL CONTINUE TO TIGHTEN THIS MORNING AS
LOW LEVEL WINDS STRENGTHEN AHEAD OF AN APPROACHING COLD FRONT.
ALREADY HAD A SHIP WEST OF BEAVER ISLAND OF 32 KTS AT 07Z.
CONTINUED THE OCCASIONAL GALE GUST WORDING BUT DESPITE A VERY
STRONG MARINE LAYER/INVERSION...ITS POSSIBLE THAT MORE PREVAILING
GALES MAY DEVELOP LATER THIS MORNING AND CONTINUE THIS
AFTERNOON...MAINLY OVER THE NORTHERN THIRD/HALF OF THE LAKE. THIS
WILL NEED TO BE MONITORED FOR A POSSIBLE GALE WARNING. THE COLD
FRONT WILL MOVE ACROSS THE LAKE LATE THIS AFTERNOON INTO EARLY
THIS EVENING... SHIFTING WINDS TO THE NORTHWEST AND STRONG GUSTS
MAY ACCOMPANY THE PASSAGE OF THE FRONT. NORTHWEST WINDS WILL
SLOWLY DIMINISH TO 15-25 KTS FRIDAY AS HIGH PRESSURE BUILDS ACROSS
THE PLAINS. THIS HIGH WILL SPREAD EAST ACROSS THE WESTERN LAKES
FRIDAY NIGHT INTO SATURDAY WITH WINDS DIMINISHING FURTHER BUT THE
HIGH THEN BECOMES STATIONARY ACROSS THE WESTERN LAKES AS THE
STRONG REMNANTS OF SANDY MOVE NORTH ALONG THE EAST COAST SUNDAY
AND MONDAY. THERE REMAINS QUITE A BIT OF UNCERTAINTY EARLY/MID
NEXT WEEK BUT IF CURRENT TRENDS CONTINUE...THERE COULD BE A
PROLONGED PERIOD OF NORTHERLY WINDS. CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
LMZ669-LMZ868-LMZ870 UNTIL 10 PM THURSDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 10 PM SATURDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
232 PM CDT THU OCT 25 2012
.DISCUSSION...
1251 PM CDT
NO BIG CHANGES IN OVERALL FORECAST THINKING THIS AFTERNOON. WE DID
SLOW FRONTAL TIMING SLIGHTLY...NOW EXPECT FRONT THROUGH THE ROCKFORD
AREA AROUND 4PM CDT AND ACROSS THE CHICAGO METRO BETWEEN 6PM AND 8PM
DEPENDING ON YOUR LOCATION. LATEST RAP GUIDANCE SUGGESTS 300-500
J/KG MUCAPE IMMEDIATELY ALONG THE FRONT WITH 50-60KT DEEP LAYER
SHEAR. EXPECT CONVECTIVE COVERAGE TO INCREASE ALONG THE FRONT OVER
NEXT FEW HOURS AS A SHORTWAVE TROUGH BEGINS TO LIFT NORTHEAST ACROSS
IOWA EARLY THIS AFTERNOON. WITH INTENSE SHEAR NOTED IMMEDIATELY
ALONG AND JUST BEHIND THE FRONT...WILL HAVE TO MONITOR FOR A
MARGINAL SEVERE WEATHER THREAT THROUGH THE AFTERNOON AND EARLY
EVENING AS FAST MOVING THUNDERSTORMS ARE EXPECTED TO DEVELOP. BMD
//PREV DISCUSSION...
333 AM CDT
EARLY THIS MORNING AN ACTIVE ATMOSPHERIC RIVER WAS RIDING ALONG THE
FRONTAL BOUNDARY FROM CENTRAL KANSAS NORTHEAST THROUGH LAKE
SUPERIOR. A SERIES OF CONVECTIVE COMPLEXES DEVELOPED LATE LAST NIGHT
AND CONTINUE EARLY THIS MORNING. ACROSS NORTHERN IL/NORTHWEST IN
FLOW REMAINS SOUTHERLY WITH VERY MILD AND MOIST CONDS. DEW PTS HAVE
REMAINED IN THE LOW 60S OVERNIGHT...WHICH BASED ON CLIMATOLOGY IS A
FEW DEGREES WARMER THAN THE NORMAL HIGH TEMPS ON THIS DATE. IT
APPEARS THE DAY WILL START OFF WITH JUST SOME HIGH BASED CLOUDS
OVERHEAD...WHICH WILL ALLOW THE SFC TO WARM-UP EFFICIENTLY. WITH
SOME POTENTIAL FOR COMPRESSIONAL WARMING TO TAKE PLACE...TEMPS
ACROSS THE CWFA COULD EASILY PUSH BACK INTO THE UPR 70S TDY...AND
COULD SEE A FEW 80 DEG READINGS SOUTH OF A PONTIAC TO KANKAKEE LINE.
THEN THE LARGER FOCUS WILL BE ON THE PRECIP ARRIVAL...CONVECTION
CHANCES...AND FRONTAL PASSAGE. MINIMAL ADJUSTMENTS TO THE PREVIOUS
FORECAST...AS IT APPEARS THE FRONT SHUD ARRIVE ACROSS THE FAR
WESTERN CWFA ARND 18-21Z. LAPSE RATES STEEPEN...AND MUCAPE VALUES
ARE PROGGED TO APPROACH 1000J/KG THIS AFTN. THE BEST SHEAR SHUD PASS
WELL NORTH OF THE REGION...HOWEVER THE ENVIRONMENT OVERHEAD WILL
BECOME FAVORABLE FOR CONVECTION EARLY THIS AFTERNOON THROUGH EARLY
THIS EVENING FROM WEST TO EAST. HI-RES GUIDANCE WAS SUGGESTING THAT
PRECIP MAY BE MORE PLENTIFUL IMMEDIATELY BEHIND THE BNDRY. HAVE
MAINTAINED MENTION OF CONVECTION...HOWEVER HAVE TRIMMED BACK FROM
THE DEFINITE MENTION TO LIKELY. COULD EVEN SEE THIS BEING TRIMMED
BACK TO CHC THUNDER.
THEN THE BDNRY STEADILY MARCHES EAST ACROSS THE CWFA WITH WINDS
TURNING WEST/NORTHWEST BY 00Z...AND EXPECT THE FRONT TO HAVE PUSHED
EAST OF NORTHWEST IN AROUND 3Z FRI. THE CONVECTIVE THREAT WILL
RAPIDLY DIMINISH AS WELL AS THE DRY AIR STEADILY ARRIVES LATE THIS
AFTN. TEMPS WILL ALSO QUICKLY FALL POST FRONTAL...AND EXPECT BY 00Z
LOCATIONS WEST OF A PONTIAC TO CRYSTAL LAKE LINE WILL HAVE TEMPS
ALREADY IN THE UPR 40S. THEN THEY WILL CONTINUE TO RADIATE WITH LOWS
IN THE MID 30S ACROSS THE FAR NORTHWEST...AND LOW 40S FOR NORTHWEST
IN.
FRIDAY THROUGH SUNDAY...
500MB TROUGH AXIS WILL PUSH EAST ACROSS THE GREAT LAKES REGION
FRI...THEN BEGIN TO WEAKEN THROUGH THE SECOND HALF OF THE WEEKEND.
HOWEVER...DESPITE THE WEAKENING THE GENERAL THEME WILL FEATURE A
NORTHWEST FLOW. STRONG 500MB RIDGE WILL REMAIN IN PLACE ACROSS THE
CANADIAN MARITIME THROUGH THE WEEKEND...WHICH COULD SLOW THE
WEAKENING OF THE TROUGH OVER THE GREAT LAKES. ENSEMBLES ARE
DEMONSTRATING MINIMAL SPREAD AMONGST EACH MEMBER...THUS EXHIBITING A
HIGH CONFIDENCE.
SFC ANTI-CYCLONIC FLOW RAPIDLY PUSHES IN BEHIND THE COLD FRONT
FRI...AND SHUD AID IN A QUICK EROSION TO THE CLOUDS/PRECIP. 850MB
THERMAL TROUGH WILL STEADILY BUILD OVERHEAD FRI...WITH TEMPS MIDDAY
OF 0 TO -2 DEG C. AT THIS TIME IT APPEARS THE BULK OF FRI WILL
REMAIN DRY...HOWEVER CONDITIONS WILL BE STEADILY DEVELOPING FOR LAKE
EFFECT PRECIP GENERATION FRI EVE.
LAKE EFFECT PRECIP LOOKS PROBABLE FOR FRI NGT THRU SUN...AS FLOW
WILL GENERALLY BE NORTH. AT TIMES THE WINDS MAY VEER MORE TO THE
NORTHEAST...WHICH WOULD FAVOR A BUCKLE IN THE EXPECTED LAKE EFFECT
PRECIP COVERAGE AND PUSH IT OVER CHICAGO/WAUKEGAN. TEMPS DURING THE
DAY SHUD WARM ENOUGH TO KEEP PRECIP IN A LIQUID STATE OR SHRA. THEN
OVERNIGHT TEMPS ARE EXPECTED TO RADIATE INTO THE LOW/MID 30S...WHICH
MAY ALLOW FOR SOME WET SNOW TO BECOME MIXED WITH THE LGT RA.
OTHERWISE AREAS AWAY FROM LAKE MICHIGAN OR WEST OF I-355...SHOULD
SEE DRY WEATHER THRU THE FRI-SUN PERIODS AND PSBLY SUNNY SKIES.
AFTERNOON TEMPS SAT/SUN WILL STRUGGLE TO WARM WITH THE CONTINUED
FEED OF COLD AIR ADVECTION INTO THE AREA. BASED OFF OF THE PLUMES
AND GUIDANCE FOR THIS TIMEFRAME...MANY LOCATIONS MAY STRUGGLE TO
WARM BEYOND THE LOW/MID 40S. IT IS CONCEIVABLE THAT A FEW AREAS
NORTH OF I-88 COULD SEE TEMPS HOLD IN THE UPR 30S SAT.
MONDAY THROUGH WEDNESDAY...
THE FINAL FEW PERIODS OF THE EXTENDED BECOME VERY CHALLENGING. THE
AFOREMENTIONED HIGH LATITUDE RIDGING OVER THE CANADIAN MARITIME IS
PROGGED TO MAINTAIN ITSELF...AND GUIDANCE IS INDICATING THAT THE
TROUGH OVER THE GREAT LAKES WILL INITIALLY WEAKEN. THEN THIS TROUGH
WILL UNDERGO SOME ENHANCEMENT TUE/WED. THE OTHER CHALLENGE IS THE
TROPICAL SYSTEM IN THE WESTERN ATLANTIC...WHICH GUIDANCE HAS BEEN
SUGGESTING WILL SKIRT THE EAST COAST.
ONCE THE TROPICAL SYSTEM...SANDY...APPROACHES THE NEW ENGLAND AREA
GUIDANCE IS SUGGESTING IT WILL MERGE WITH THE TROUGH AND AMPLIFY.
THIS COULD RESULT IN A SLUG OF PRECIP PIVOTING WEST/SOUTHWEST ACROSS
LOWER MICHIGAN TUE AND ARRIVE ACROSS NORTHERN IL/NORTHWEST IN TUE
NGT/WED.
OVERALL THE TEMP OUTLOOK FOR THE EXTENDED PERIODS WILL REMAIN
COOL...WITH TEMPS GENERALLY IN THE MID/UPR 40S TO PSBLY LOW 50S
TUE/WED. OVERNIGHT LOWS WILL HINGE UPON CLOUD COVER...HOWEVER AT
THIS TIME ANTICIPATE TEMPS IN THE UPR 20S TO LOW 30S.
BEACHLER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* SOUTH WINDS GUSTING TO NEAR 30 KT BECOMING NORTHWEST LATE THIS
AFTERNOON. A BRIEF PERIOD OF STRONGER THAN 30KT NW WINDS ARE
POSSIBLE IMMEDIATELY BEHIND THE FRONT...BUT THEN SUBSIDING
THEREAFTER.
* SHOWERS ALONG AND MAINLY BEHIND A COLD FRONT...WITH SCATTERED
THUNDERSTORMS ALSO POSSIBLE.
* MVFR/IFR CIGS IMMEDIATELY BEHIND THE COLD FRONT. BMD
//DISCUSSION...UPDATED 18Z...
A STRONG COLD FRONT IS BEGINNING TO PUSH INTO NORTHWESTERN ILLINOIS
EARLY THIS AFTERNOON. AHEAD OF THE FRONT...BKN STRATUS DECK AROUND
040 HAS OVERSPREAD MOST OF THE NORTHERN ILLINOIS TERMINALS WITH SSW
WINDS GUSTING AROUND 30KT. EXPECT LITTLE TO CHANGE OVER THE NEXT
SEVERAL HOURS AHEAD OF THE FRONT EXCEPT FOR SOME LOWING OF CIGS TO
020-025. BASED ON FAIRLY GOOD AGREEMENT BETWEEN VARIOUS HOURLY
MODELS AND A RADAR FIX ON THE COLD FRONT...HAVE FAIRLY HIGH
CONFIDENCE IN FRONTAL TIMING LATE THIS AFTERNOON AND EARLY EVENING.
DID BUMP BACK TIMING SLIGHTLY WITH THE 18Z ISSUANCE TO MATCH LATEST
THINKING. A LITTLE LESS CERTAIN ARE THE CONVECTIVE CHANCES WITH THIS
SYSTEM. THERE IS MODEST INSTABILITY ALONG THE FRONT WITH STRONG
FORCING AND SUSPECT THAT SCT/BKN LINE TSRA WILL CONTINUE TO DEVELOP
ALONG THE FRONT THIS AFTERNOON. NOT SURE AT THIS POINT HOW EXTENSIVE
THE COVERAGE MAY BECOME SO WILL STICK WITH VCTS FOR NOW.
IMMEDIATELY BEHIND THE FRONT...EXPECT CONDITIONS TO RAPIDLY
DETERIORATE. RAIN WILL OVERSPREAD THE AREA WITH THE THREAT FOR SOME
EMBEDDED THUNDERSTORMS CONTINUING FOR AN HOUR OR SO AFTER FROPA.
EXPECT CIGS TO QUICKLY FALL INTO LOW END MVFR AND IFR CATEGORY...AND
STILL CANNOT RULE OUT LIFR...THOUGH ONLY NAM SOUNDINGS ARE
STRONGLY IN FAVOR OF THIS. WINDS WILL SHIFT TO THE NORTHWEST AND
THERE MAY BE A SHORT PERIOD WHERE WIND GUSTS IN EXCESS OF 30 KT
ARE POSSIBLE AS A STRONG AIR OF PRESSURE RISES MOVES ACROSS THE
TERMINALS. OVERNIGHT...EXPECT CONDITIONS TO GRADUALLY IMPROVE BACK
TO MVFR...THEN VFR WITH WINDS DIMINISHING AS HIGH PRESSURE BUILDS
IN FROM THE WEST. VFR CONDITIONS SHOULD CONTINUE WITH MODERATE
NORTHWEST WINDS AROUND 12 KT AND OCCASIONAL GUSTS ON FRIDAY. BMD
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE IN WIND DIRECTION/SPEEDS THROUGH THIS EVENING.
MEDIUM CONFIDENCE IN SPEEDS OVERNIGHT AND FRIDAY.
* HIGH CONFIDENCE IN FROPA/PRECIP TIMING.
* HIGH CONFIDENCE IN CIGS DROPPING BELOW 015...MEDIUM CONFIDENCE
IN DROPPING BELOW 010. BMD
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
* FRIDAY NIGHT THROUGH MONDAY...PREDOMINANTLY VFR. SMALL THREAT OF
LOCALIZED LAKE EFFECT MVFR CIGS AND SLIGHT CHANCE OF SHRA.
* TUESDAY AND WEDNESDAY...VFR.
&&
.MARINE...
347 AM...THE GRADIENT WILL CONTINUE TO TIGHTEN THIS MORNING AS
LOW LEVEL WINDS STRENGTHEN AHEAD OF AN APPROACHING COLD FRONT.
ALREADY HAD A SHIP WEST OF BEAVER ISLAND OF 32 KTS AT 07Z.
CONTINUED THE OCCASIONAL GALE GUST WORDING BUT DESPITE A VERY
STRONG MARINE LAYER/INVERSION...ITS POSSIBLE THAT MORE PREVAILING
GALES MAY DEVELOP LATER THIS MORNING AND CONTINUE THIS
AFTERNOON...MAINLY OVER THE NORTHERN THIRD/HALF OF THE LAKE. THIS
WILL NEED TO BE MONITORED FOR A POSSIBLE GALE WARNING. THE COLD
FRONT WILL MOVE ACROSS THE LAKE LATE THIS AFTERNOON INTO EARLY
THIS EVENING... SHIFTING WINDS TO THE NORTHWEST AND STRONG GUSTS
MAY ACCOMPANY THE PASSAGE OF THE FRONT. NORTHWEST WINDS WILL
SLOWLY DIMINISH TO 15-25 KTS FRIDAY AS HIGH PRESSURE BUILDS ACROSS
THE PLAINS. THIS HIGH WILL SPREAD EAST ACROSS THE WESTERN LAKES
FRIDAY NIGHT INTO SATURDAY WITH WINDS DIMINISHING FURTHER BUT THE
HIGH THEN BECOMES STATIONARY ACROSS THE WESTERN LAKES AS THE
STRONG REMNANTS OF SANDY MOVE NORTH ALONG THE EAST COAST SUNDAY
AND MONDAY. THERE REMAINS QUITE A BIT OF UNCERTAINTY EARLY/MID
NEXT WEEK BUT IF CURRENT TRENDS CONTINUE...THERE COULD BE A
PROLONGED PERIOD OF NORTHERLY WINDS. CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
LMZ669-LMZ868-LMZ870 UNTIL 10 PM THURSDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 10 PM SATURDAY.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS CHICAGO/ROMEOVILLE IL
1252 PM CDT THU OCT 25 2012
.DISCUSSION...
1251 PM CDT
NO BIG CHANGES IN OVERALL FORECAST THINKING THIS AFTERNOON. WE DID
SLOW FRONTAL TIMING SLIGHTLY...NOW EXPECT FRONT THROUGH THE ROCKFORD
AREA AROUND 4PM CDT AND ACROSS THE CHICAGO METRO BETWEEN 6PM AND 8PM
DEPENDING ON YOUR LOCATION. LATEST RAP GUIDANCE SUGGESTS 300-500
J/KG MUCAPE IMMEDIATELY ALONG THE FRONT WITH 50-60KT DEEP LAYER
SHEAR. EXPECT CONVECTIVE COVERAGE TO INCREASE ALONG THE FRONT OVER
NEXT FEW HOURS AS A SHORTWAVE TROUGH BEGINS TO LIFT NORTHEAST ACROSS
IOWA EARLY THIS AFTERNOON. WITH INTENSE SHEAR NOTED IMMEDIATELY
ALONG AND JUST BEHIND THE FRONT...WILL HAVE TO MONITOR FOR A
MARGINAL SEVERE WEATHER THREAT THROUGH THE AFTERNOON AND EARLY
EVENING AS FAST MOVING THUNDERSTORMS ARE EXPECTED TO DEVELOP. BMD
&&
.PREV DISCUSSION...
333 AM CDT
EARLY THIS MORNING AN ACTIVE ATMOSPHERIC RIVER WAS RIDING ALONG THE
FRONTAL BOUNDARY FROM CENTRAL KANSAS NORTHEAST THROUGH LAKE
SUPERIOR. A SERIES OF CONVECTIVE COMPLEXES DEVELOPED LATE LAST NIGHT
AND CONTINUE EARLY THIS MORNING. ACROSS NORTHERN IL/NORTHWEST IN
FLOW REMAINS SOUTHERLY WITH VERY MILD AND MOIST CONDS. DEW PTS HAVE
REMAINED IN THE LOW 60S OVERNIGHT...WHICH BASED ON CLIMATOLOGY IS A
FEW DEGREES WARMER THAN THE NORMAL HIGH TEMPS ON THIS DATE. IT
APPEARS THE DAY WILL START OFF WITH JUST SOME HIGH BASED CLOUDS
OVERHEAD...WHICH WILL ALLOW THE SFC TO WARM-UP EFFICIENTLY. WITH
SOME POTENTIAL FOR COMPRESSIONAL WARMING TO TAKE PLACE...TEMPS
ACROSS THE CWFA COULD EASILY PUSH BACK INTO THE UPR 70S TDY...AND
COULD SEE A FEW 80 DEG READINGS SOUTH OF A PONTIAC TO KANKAKEE LINE.
THEN THE LARGER FOCUS WILL BE ON THE PRECIP ARRIVAL...CONVECTION
CHANCES...AND FRONTAL PASSAGE. MINIMAL ADJUSTMENTS TO THE PREVIOUS
FORECAST...AS IT APPEARS THE FRONT SHUD ARRIVE ACROSS THE FAR
WESTERN CWFA ARND 18-21Z. LAPSE RATES STEEPEN...AND MUCAPE VALUES
ARE PROGGED TO APPROACH 1000J/KG THIS AFTN. THE BEST SHEAR SHUD PASS
WELL NORTH OF THE REGION...HOWEVER THE ENVIRONMENT OVERHEAD WILL
BECOME FAVORABLE FOR CONVECTION EARLY THIS AFTERNOON THROUGH EARLY
THIS EVENING FROM WEST TO EAST. HI-RES GUIDANCE WAS SUGGESTING THAT
PRECIP MAY BE MORE PLENTIFUL IMMEDIATELY BEHIND THE BNDRY. HAVE
MAINTAINED MENTION OF CONVECTION...HOWEVER HAVE TRIMMED BACK FROM
THE DEFINITE MENTION TO LIKELY. COULD EVEN SEE THIS BEING TRIMMED
BACK TO CHC THUNDER.
THEN THE BDNRY STEADILY MARCHES EAST ACROSS THE CWFA WITH WINDS
TURNING WEST/NORTHWEST BY 00Z...AND EXPECT THE FRONT TO HAVE PUSHED
EAST OF NORTHWEST IN AROUND 3Z FRI. THE CONVECTIVE THREAT WILL
RAPIDLY DIMINISH AS WELL AS THE DRY AIR STEADILY ARRIVES LATE THIS
AFTN. TEMPS WILL ALSO QUICKLY FALL POST FRONTAL...AND EXPECT BY 00Z
LOCATIONS WEST OF A PONTIAC TO CRYSTAL LAKE LINE WILL HAVE TEMPS
ALREADY IN THE UPR 40S. THEN THEY WILL CONTINUE TO RADIATE WITH LOWS
IN THE MID 30S ACROSS THE FAR NORTHWEST...AND LOW 40S FOR NORTHWEST
IN.
FRIDAY THROUGH SUNDAY...
500MB TROUGH AXIS WILL PUSH EAST ACROSS THE GREAT LAKES REGION
FRI...THEN BEGIN TO WEAKEN THROUGH THE SECOND HALF OF THE WEEKEND.
HOWEVER...DESPITE THE WEAKENING THE GENERAL THEME WILL FEATURE A
NORTHWEST FLOW. STRONG 500MB RIDGE WILL REMAIN IN PLACE ACROSS THE
CANADIAN MARITIME THROUGH THE WEEKEND...WHICH COULD SLOW THE
WEAKENING OF THE TROUGH OVER THE GREAT LAKES. ENSEMBLES ARE
DEMONSTRATING MINIMAL SPREAD AMONGST EACH MEMBER...THUS EXHIBITING A
HIGH CONFIDENCE.
SFC ANTI-CYCLONIC FLOW RAPIDLY PUSHES IN BEHIND THE COLD FRONT
FRI...AND SHUD AID IN A QUICK EROSION TO THE CLOUDS/PRECIP. 850MB
THERMAL TROUGH WILL STEADILY BUILD OVERHEAD FRI...WITH TEMPS MIDDAY
OF 0 TO -2 DEG C. AT THIS TIME IT APPEARS THE BULK OF FRI WILL
REMAIN DRY...HOWEVER CONDITIONS WILL BE STEADILY DEVELOPING FOR LAKE
EFFECT PRECIP GENERATION FRI EVE.
LAKE EFFECT PRECIP LOOKS PROBABLE FOR FRI NGT THRU SUN...AS FLOW
WILL GENERALLY BE NORTH. AT TIMES THE WINDS MAY VEER MORE TO THE
NORTHEAST...WHICH WOULD FAVOR A BUCKLE IN THE EXPECTED LAKE EFFECT
PRECIP COVERAGE AND PUSH IT OVER CHICAGO/WAUKEGAN. TEMPS DURING THE
DAY SHUD WARM ENOUGH TO KEEP PRECIP IN A LIQUID STATE OR SHRA. THEN
OVERNIGHT TEMPS ARE EXPECTED TO RADIATE INTO THE LOW/MID 30S...WHICH
MAY ALLOW FOR SOME WET SNOW TO BECOME MIXED WITH THE LGT RA.
OTHERWISE AREAS AWAY FROM LAKE MICHIGAN OR WEST OF I-355...SHOULD
SEE DRY WEATHER THRU THE FRI-SUN PERIODS AND PSBLY SUNNY SKIES.
AFTERNOON TEMPS SAT/SUN WILL STRUGGLE TO WARM WITH THE CONTINUED
FEED OF COLD AIR ADVECTION INTO THE AREA. BASED OFF OF THE PLUMES
AND GUIDANCE FOR THIS TIMEFRAME...MANY LOCATIONS MAY STRUGGLE TO
WARM BEYOND THE LOW/MID 40S. IT IS CONCEIVABLE THAT A FEW AREAS
NORTH OF I-88 COULD SEE TEMPS HOLD IN THE UPR 30S SAT.
MONDAY THROUGH WEDNESDAY...
THE FINAL FEW PERIODS OF THE EXTENDED BECOME VERY CHALLENGING. THE
AFOREMENTIONED HIGH LATITUDE RIDGING OVER THE CANADIAN MARITIME IS
PROGGED TO MAINTAIN ITSELF...AND GUIDANCE IS INDICATING THAT THE
TROUGH OVER THE GREAT LAKES WILL INITIALLY WEAKEN. THEN THIS TROUGH
WILL UNDERGO SOME ENHANCEMENT TUE/WED. THE OTHER CHALLENGE IS THE
TROPICAL SYSTEM IN THE WESTERN ATLANTIC...WHICH GUIDANCE HAS BEEN
SUGGESTING WILL SKIRT THE EAST COAST.
ONCE THE TROPICAL SYSTEM...SANDY...APPROACHES THE NEW ENGLAND AREA
GUIDANCE IS SUGGESTING IT WILL MERGE WITH THE TROUGH AND AMPLIFY.
THIS COULD RESULT IN A SLUG OF PRECIP PIVOTING WEST/SOUTHWEST ACROSS
LOWER MICHIGAN TUE AND ARRIVE ACROSS NORTHERN IL/NORTHWEST IN TUE
NGT/WED.
OVERALL THE TEMP OUTLOOK FOR THE EXTENDED PERIODS WILL REMAIN
COOL...WITH TEMPS GENERALLY IN THE MID/UPR 40S TO PSBLY LOW 50S
TUE/WED. OVERNIGHT LOWS WILL HINGE UPON CLOUD COVER...HOWEVER AT
THIS TIME ANTICIPATE TEMPS IN THE UPR 20S TO LOW 30S.
BEACHLER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* SOUTH WINDS GUSTING TO NEAR 30 KT BECOMING NORTHWEST LATE THIS
AFTERNOON. A BRIEF PERIOD OF STRONGER THAN 30KT NW WINDS ARE
POSSIBLE IMMEDIATELY BEHIND THE FRONT...BUT THEN SUBSIDING
THEREAFTER.
* SHOWERS ALONG AND MAINLY BEHIND A COLD FRONT...WITH SCATTERED
THUNDERSTORMS ALSO POSSIBLE.
* MVFR/IFR CIGS IMMEDIATELY BEHIND THE COLD FRONT...POSSIBLY BRIEF
LIFR. BMD
//DISCUSSION...UPDATED 18Z...
A STRONG COLD FRONT IS BEGINNING TO PUSH INTO NORTHWESTERN ILLINOIS
EARLY THIS AFTERNOON. AHEAD OF THE FRONT...BKN STRATUS DECK AROUND
040 HAS OVERSPREAD MOST OF THE NORTHERN ILLINOIS TERMINALS WITH SSW
WINDS GUSTING AROUND 30KT. EXPECT LITTLE TO CHANGE OVER THE NEXT
SEVERAL HOURS AHEAD OF THE FRONT EXCEPT FOR SOME LOWING OF CIGS TO
020-025. BASED ON FAIRLY GOOD AGREEMENT BETWEEN VARIOUS HOURLY
MODELS AND A RADAR FIX ON THE COLD FRONT...HAVE FAIRLY HIGH
CONFIDENCE IN FRONTAL TIMING LATE THIS AFTERNOON AND EARLY EVENING.
DID BUMP BACK TIMING SLIGHTLY WITH THE 18Z ISSUANCE TO MATCH LATEST
THINKING. A LITTLE LESS CERTAIN ARE THE CONVECTIVE CHANCES WITH THIS
SYSTEM. THERE IS MODEST INSTABILITY ALONG THE FRONT WITH STRONG
FORCING AND SUSPECT THAT SCT/BKN LINE TSRA WILL CONTINUE TO DEVELOP
ALONG THE FRONT THIS AFTERNOON. NOT SURE AT THIS POINT HOW EXTENSIVE
THE COVERAGE MAY BECOME SO WILL STICK WITH VCTS FOR NOW.
IMMEDIATELY BEHIND THE FRONT...EXPECT CONDITIONS TO RAPIDLY
DETERIORATE. RAIN WILL OVERSPREAD THE AREA WITH THE THREAT FOR SOME
EMBEDDED THUNDERSTORMS CONTINUING FOR AN HOUR OR SO AFTER FROPA.
EXPECT CIGS TO QUICKLY FALL INTO LOW END MVFR AND IFR CATEGORY...AND
STILL CANNOT RULE OUT LIFR...THOUGH ONLY NAM SOUNDINGS ARE
STRONGLY IN FAVOR OF THIS. WINDS WILL SHIFT TO THE NORTHWEST AND
THERE MAY BE A SHORT PERIOD WHERE WIND GUSTS IN EXCESS OF 30 KT
ARE POSSIBLE AS A STRONG AIR OF PRESSURE RISES MOVES ACROSS THE
TERMINALS. OVERNIGHT...EXPECT CONDITIONS TO GRADUALLY IMPROVE BACK
TO MVFR...THEN VFR WITH WINDS DIMINISHING AS HIGH PRESSURE BUILDS
IN FROM THE WEST. VFR CONDITIONS SHOULD CONTINUE WITH MODERATE
NORTHWEST WINDS AROUND 12 KT AND OCCASIONAL GUSTS ON FRIDAY. BMD
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH CONFIDENCE IN WIND DIRECTION/SPEEDS THROUGH THIS EVENING.
MEDIUM CONFIDENCE IN SPEEDS OVERNIGHT AND FRIDAY.
* HIGH CONFIDENCE IN FROPA/PRECIP TIMING.
* HIGH CONFIDENCE IN CIGS DROPPING BELOW 015 AND LIKELY 010...LOW
TO MEDIUM CONFIDENCE IN LESS THAN 005. BMD
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
* FRIDAY NIGHT THROUGH MONDAY...PREDOMINANTLY VFR. SMALL THREAT OF
LOCALIZED LAKE EFFECT MVFR CIGS AND SLIGHT CHANCE OF SHRA.
* TUESDAY AND WEDNESDAY...VFR.
&&
.MARINE...
347 AM...THE GRADIENT WILL CONTINUE TO TIGHTEN THIS MORNING AS
LOW LEVEL WINDS STRENGTHEN AHEAD OF AN APPROACHING COLD FRONT.
ALREADY HAD A SHIP WEST OF BEAVER ISLAND OF 32 KTS AT 07Z.
CONTINUED THE OCCASIONAL GALE GUST WORDING BUT DESPITE A VERY
STRONG MARINE LAYER/INVERSION...ITS POSSIBLE THAT MORE PREVAILING
GALES MAY DEVELOP LATER THIS MORNING AND CONTINUE THIS
AFTERNOON...MAINLY OVER THE NORTHERN THIRD/HALF OF THE LAKE. THIS
WILL NEED TO BE MONITORED FOR A POSSIBLE GALE WARNING. THE COLD
FRONT WILL MOVE ACROSS THE LAKE LATE THIS AFTERNOON INTO EARLY
THIS EVENING... SHIFTING WINDS TO THE NORTHWEST AND STRONG GUSTS
MAY ACCOMPANY THE PASSAGE OF THE FRONT. NORTHWEST WINDS WILL
SLOWLY DIMINISH TO 15-25 KTS FRIDAY AS HIGH PRESSURE BUILDS ACROSS
THE PLAINS. THIS HIGH WILL SPREAD EAST ACROSS THE WESTERN LAKES
FRIDAY NIGHT INTO SATURDAY WITH WINDS DIMINISHING FURTHER BUT THE
HIGH THEN BECOMES STATIONARY ACROSS THE WESTERN LAKES AS THE
STRONG REMNANTS OF SANDY MOVE NORTH ALONG THE EAST COAST SUNDAY
AND MONDAY. THERE REMAINS QUITE A BIT OF UNCERTAINTY EARLY/MID
NEXT WEEK BUT IF CURRENT TRENDS CONTINUE...THERE COULD BE A
PROLONGED PERIOD OF NORTHERLY WINDS. CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
LMZ669-LMZ868-LMZ870 UNTIL 10 PM THURSDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 10 PM SATURDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1028 PM EDT FRI OCT 26 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 252 PM EDT FRI OCT 26 2012
THE SHOWERS WILL BE ENDING ACROSS SOUTHEASTERN AND EAST CENTRAL
PARTS OF CENTRAL INDIANA AROUND SUNRISE AS A COLD FRONT STALLS
ACROSS THE APPALACHIANS. AFTER THAT...EXPECT WELL BELOW NORMAL
TEMPERATURES TO CONTINUE THROUGH NEXT WEEK AS HIGH PRESSURE SETTLES
IN ACROSS THE MISSISSIPPI AND WABASH VALLEYS. IT WILL BE MOSTLY
DRY...HOWEVER THERE IS A CHANCE OF SHOWERS ACROSS ALL BUT SOUTHWEST
PARTS OF CENTRAL INDIANA TUESDAY THROUGH WEDNESDAY ASSOCIATED WITH
SANDY. THE RAIN SHOWERS COULD MIX WITH SNOW TUESDAY NIGHT.
AFTERNOON HIGHS THROUGH NEXT WEEK WILL ONLY BE IN THE 40S AND
50S...WHILE OVERNIGHT LOWS WILL BE IN THE 30S.
&&
.NEAR TERM /REST OF TONIGHT/...
ISSUED AT 945 PM EDT FRI OCT 26 2012
APPEARS THAT MAJORITY OF SHOWER ACTIVITY HAS ENDED ACROSS EASTERN
PORTION OF THE FORECAST AREA...BUT WHAT IS LEFT ALONG WITH
POTENTIAL FOR SHOWERS TO THE SOUTH TO BRUSH EASTERN BORDER MERITS
MAINTAINING A SLIGHT CHANCE TO VERY LOW CHANCE ALONG THE
EASTERN/SOUTHEASTERN HALF OR SO OF THE AREA.
OTHERWISE...TIGHTENED UP TEMPERATURE GRADIENT IN MINS OVERNIGHT AS
THERE SHOULD BE CLOUD ACROSS MUCH OF THE EASTERN PORTION OF THE
AREA MOST OF THE NIGHT...WITH WESTERN PORTIONS SEEING MUCH MORE
CLEAR SKY TIME.
&&
.SHORT TERM /SATURDAY THROUGH MONDAY/...
ISSUED AT 252 PM EDT FRI OCT 26 2012
MAIN CHALLENGE TO THE SHORT TERM WILL BE WHETHER TO KEEP ANY MORNING
POPS IN ON SATURDAY AND THEN WHETHER OR NOT THE EAST SEES ANY SHOWER
ACTIVITY MONDAY FROM SANDY. TEMPERATURES AND POSSIBLE OVERNIGHT
FREEZING WILL ALSO BE A MAIN FOCUS.
AT THIS POINT...ALL THE 12Z MODEL RUNS AND THE 00Z ECMWF SUGGEST THE
SHOWERS WILL BE JUST EAST OF EAST CENTRAL INDIANA BY 12Z SATURDAY
WITH DECREASING CLOUD COVER. ALTHOUGH CLOUD COVER WILL BE ON THE LOW
SIDE...NORTH AND NORTHEAST WINDS TO AROUND 15 MPH AND GUSTING TO
AROUND 20 WILL KEEP TEMPERATURES DOWN TOWARDS THE COOLER GFS MOS IN
THE LOWER 50S FOR AFTERNOON HIGHS. MODELS ARE ALL BRINGING SOME HIGH
CLOUDS IN SATURDAY NIGHT AHEAD OF AN UPPER TROUGH. HOWEVER...WITH
THE NORTH WINDS CONTINUING AT 5 TO 10 MPH...TEMPERATURES NEAR
FREEZING PER SIMILAR MOS LOOK GOOD. NOT ENOUGH CONFIDENCE IN
WIDESPREAD FREEZING AT THIS TIME TO ISSUE ANY HEADLINES FOR OUR
SOUTHERN TWO TIERS...WHERE THEY HAVE YET TO HAVE A HARD FREEZE THIS
FALL. SUNDAY SHOULD BE NEAR A CARBON COPY OF SATURDAY EXCEPT
SLIGHTLY COOLER STILL WITH JUST SOME HIGH CLOUDS AND NORTH WINDS
CONTINUING NEAR 15 MPH WITH GUSTS TO NEAR 20. 850 MILLIBAR
TEMPERATURES COOL A COUPLE OF DEGREES TO -2 TO -4 DEGREES CELSIUS
LATE SUNDAY WHICH SHOULD RESULT IN AFTERNOON HIGHS ONLY IN THE UPPER
40S TO LOWER 50S PER THE COOLER 12Z GFS MOS AND ALLBLEND. SUNDAY
NIGHT...MODELS AGREE ON A DRY COLUMN WITH SOME LIGHTER NORTH AND
NORTHWEST WINDS WHICH SHOULD ALLOW FOR TEMPERATURES A COUPLE OF
DEGREES COLDER SUNDAY NIGHT THAN SATURDAY NIGHT. MOST AREAS WILL
SHOULD SEE TEMPERATURES RIGHT AROUND THE FREEZING MARK...SO COULD
VERY WELL SEE HEADLINES FOR OUR SOUTHERN COUNTIES...BUT FOR NOW A
BIT EARLY. FINALLY...THE 00Z ECMWF WAS BY FAR THE FURTHEST WEST OF
THE MODELS REGARDING SANDY 00Z MONDAY...AND THE EURO BRINGS LOW QPF
AS FAR EAST AS RANDOLPH COUNTY. THE OTHER MODELS...ESPECIALLY THE
12Z GFS...ARE MUCH FURTHER NORTHEAST WITH SANDY AND HAVE THE QPF
WELL EAST OF OUR COUNTY WARNING AREA. ALTHOUGH...HPC AND THE
HURRICANE CENTER`S OFFICIAL FORECAST SIDE WITH THE EURO...HAVE TO
LEND AT LEAST SMALL CREDENCE TO THE OTHER MODELS AND KEEP POPS OUT
OF OUR EAST FOR NOW ON MONDAY. TEMPERATURES WILL CONTINUE TO BE WELL
BELOW NORMAL DESPITE PLENTY OF SUNSHINE AS NORTHWEST WINDS TO NEAR
15 KNOTS AND GUSTS TO NEAR 20 KNOTS ARE EXPECTED.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
ISSUED AT 252 PM EDT FRI OCT 26 2012
THE LONG TERM STARTS WITH A LARGE UPPER RIDGE OVER THE WESTERN AND
CENTRAL U.S. AND A STRONG UPPER LOW /SANDY/ OFF THE EAST COAST.
THERE ARE DISCREPANCIES WITH THE HANDLING OF SANDY IN THE MODELS AND
THIS WILL IMPACT THE FORECAST HERE. THE ECMWF BRINGS THE SYSTEM
FURTHER WEST AND WOULD BRING RAIN TO THE EASTERN COUNTIES AND
PERHAPS TO THE ENTIRE AREA AS EARLY AS TUESDAY AND CONTINUING
THROUGH WEDNESDAY. THE GFS KEEPS THE SYSTEM MORE TO THE EAST AND
ONLY BRINGS IN A LITTLE RAIN IN THE NORTHEAST ON WEDNESDAY. GFS
SURFACE TEMPERATURES ARE ALSO COLDER. ENSEMBLES ARE LITTLE HELP WITH
QUITE A BIT OF VARIABILITY IN THE SOLUTIONS. THINK BEST COURSE OF
ACTION AT THIS POINT IS TO LEAVE THE ALLBLEND POPS ALONE EXCEPT FOR
MINOR TWEAKING LIKE REMOVING SMALL SLIGHT CHANCES IN THE NORTHEAST
MONDAY NIGHT AND THURSDAY. IF PRECIPITATION OCCURS BEFORE WEDNESDAY
A LA THE ECM TEMPERATURES COULD BE WARM ENOUGH FOR ALL RAIN...BUT
GFS TEMPERATURES ARE QUITE A BIT COOLER AND AFTER COLLABORATION
NECESSITATE THE INCLUSION OF A RAIN SNOW MIX. NO ACCUMULATION IS
EXPECTED IF FLAKES OCCUR.
&&
.AVIATION /DISCUSSION FOR 270300Z TAF UPDATE/...
ISSUED AT 1028 PM EDT FRI OCT 26 2012
THICKER AC DECK CONTINUES TO STEADILY SHIFT EAST THIS EVENING...AND
SHOULD CLEAR BOTH KBMG AND KIND BY 05Z. REST OF THE NIGHT SHOULD SEE
MAINLY CLEAR TO PARTLY CLOUDY SKIES AT THE TERMINALS WITH JUST SOME
HIGH LEVEL CLOUDS.
00Z DISCUSSION FOLLOWS.
WITH EXCEPTION OF BRIEF MVFR CEILINGS THIS EVENING AT KBMG...VFR
CONDITIONS ANTICIPATED THROUGHOUT THE FORECAST PERIOD.
LOW LEVEL MOISTURE AND LIGHT RAIN CONTINUES TO SLOWLY PULL AWAY TO
THE EAST. DRIER AIR WILL FILTER INTO THE REGION OVERNIGHT AS A
LARGE HIGH PRESSURE RIDGE EXPANDS INTO THE LOWER OHIO VALLEY.
MODEL SOUNDINGS AND RAP LOW LEVEL RH PROGS SHOWING BACK EDGE OF
DEEPEST MOISTURE WILL REMAIN ACROSS EASTERN INDIANA TONIGHT...AND
MAY ACTUALLY SLIP BACK INTO KBMG AND KIND. CONFIDENCE IS LOW IN
THIS POSSIBILITY AT THIS POINT...BUT WILL KEEP A FEW-SCT MENTION
OF 3-4KFT STRATOCU AT BOTH SITES ALL NIGHT. HIGH CLOUDS WILL
BECOME THE PREDOMINANT CEILING AT BOTH KHUF AND KLAF OVERNIGHT.
NORTHERLY FLOW AROUND 10KTS WILL CONTINUE OVERNIGHT.
DRIER AIR AND DEEPER SUBSIDENCE ASSOCIATED WITH THE HIGH WILL
BUILD ACROSS CENTRAL INDIANA SATURDAY WITH ABUNDANT SUNSHINE
EXPECTED. MAY SEE DIURNAL CU DURING THE AFTERNOON AT ALL TERMINALS
IN A COLD ADVECTION PATTERN. NORTHERLY WINDS WILL GUST TO 20-25KTS
DURING THE AFTERNOON AS LOWER LEVEL BECOME WELL MIXED.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...MK
NEAR TERM...NIELD
SHORT TERM...MK
LONG TERM....CP
AVIATION...RYAN
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
946 PM EDT FRI OCT 26 2012
.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 252 PM EDT FRI OCT 26 2012
THE SHOWERS WILL BE ENDING ACROSS SOUTHEASTERN AND EAST CENTRAL
PARTS OF CENTRAL INDIANA AROUND SUNRISE AS A COLD FRONT STALLS
ACROSS THE APPALACHIANS. AFTER THAT...EXPECT WELL BELOW NORMAL
TEMPERATURES TO CONTINUE THROUGH NEXT WEEK AS HIGH PRESSURE SETTLES
IN ACROSS THE MISSISSIPPI AND WABASH VALLEYS. IT WILL BE MOSTLY
DRY...HOWEVER THERE IS A CHANCE OF SHOWERS ACROSS ALL BUT SOUTHWEST
PARTS OF CENTRAL INDIANA TUESDAY THROUGH WEDNESDAY ASSOCIATED WITH
SANDY. THE RAIN SHOWERS COULD MIX WITH SNOW TUESDAY NIGHT.
AFTERNOON HIGHS THROUGH NEXT WEEK WILL ONLY BE IN THE 40S AND
50S...WHILE OVERNIGHT LOWS WILL BE IN THE 30S.
&&
.NEAR TERM /REST OF TONIGHT/...
ISSUED AT 945 PM EDT FRI OCT 26 2012
APPEARS THAT MAJORITY OF SHOWER ACTIVITY HAS ENDED ACROSS EASTERN
PORTION OF THE FORECAST AREA...BUT WHAT IS LEFT ALONG WITH
PROTENTIAL FOR SHOWERS TO THE SOUTH TO BRUSH EASTERN BORDER MERITS
MAINTAINING A SLIGHT CHANCE TO VERY LOW CHANCE ALONG THE
EASTERN/SOUTHEASTERN HALF OR SO OF THE AREA.
OTHERWISE...TIGHTENED UP TEMPERATURE GRADIENT IN MINS OVERNIGHT AS
THERE SHOULD BE CLOUD ACROSS MUCH OF THE EASTERN PORTION OF THE
AREA MOST OF THE NIGHT...WITH WESTERN PORTIONS SEEING MUCH MORE
CLEAR SKY TIME.
&&
.SHORT TERM /SATURDAY THROUGH MONDAY/...
ISSUED AT 252 PM EDT FRI OCT 26 2012
MAIN CHALLENGE TO THE SHORT TERM WILL BE WHETHER TO KEEP ANY MORNING
POPS IN ON SATURDAY AND THEN WHETHER OR NOT THE EAST SEES ANY SHOWER
ACTIVITY MONDAY FROM SANDY. TEMPERATURES AND POSSIBLE OVERNIGHT
FREEZING WILL ALSO BE A MAIN FOCUS.
AT THIS POINT...ALL THE 12Z MODEL RUNS AND THE 00Z ECMWF SUGGEST THE
SHOWERS WILL BE JUST EAST OF EAST CENTRAL INDIANA BY 12Z SATURDAY
WITH DECREASING CLOUD COVER. ALTHOUGH CLOUD COVER WILL BE ON THE LOW
SIDE...NORTH AND NORTHEAST WINDS TO AROUND 15 MPH AND GUSTING TO
AROUND 20 WILL KEEP TEMPERATURES DOWN TOWARDS THE COOLER GFS MOS IN
THE LOWER 50S FOR AFTERNOON HIGHS. MODELS ARE ALL BRINGING SOME HIGH
CLOUDS IN SATURDAY NIGHT AHEAD OF AN UPPER TROUGH. HOWEVER...WITH
THE NORTH WINDS CONTINUING AT 5 TO 10 MPH...TEMPERATURES NEAR
FREEZING PER SIMILAR MOS LOOK GOOD. NOT ENOUGH CONFIDENCE IN
WIDESPREAD FREEZING AT THIS TIME TO ISSUE ANY HEADLINES FOR OUR
SOUTHERN TWO TIERS...WHERE THEY HAVE YET TO HAVE A HARD FREEZE THIS
FALL. SUNDAY SHOULD BE NEAR A CARBON COPY OF SATURDAY EXCEPT
SLIGHTLY COOLER STILL WITH JUST SOME HIGH CLOUDS AND NORTH WINDS
CONTINUING NEAR 15 MPH WITH GUSTS TO NEAR 20. 850 MILLIBAR
TEMPERATURES COOL A COUPLE OF DEGREES TO -2 TO -4 DEGREES CELSIUS
LATE SUNDAY WHICH SHOULD RESULT IN AFTERNOON HIGHS ONLY IN THE UPPER
40S TO LOWER 50S PER THE COOLER 12Z GFS MOS AND ALLBLEND. SUNDAY
NIGHT...MODELS AGREE ON A DRY COLUMN WITH SOME LIGHTER NORTH AND
NORTHWEST WINDS WHICH SHOULD ALLOW FOR TEMPERATURES A COUPLE OF
DEGREES COLDER SUNDAY NIGHT THAN SATURDAY NIGHT. MOST AREAS WILL
SHOULD SEE TEMPERATURES RIGHT AROUND THE FREEZING MARK...SO COULD
VERY WELL SEE HEADLINES FOR OUR SOUTHERN COUNTIES...BUT FOR NOW A
BIT EARLY. FINALLY...THE 00Z ECMWF WAS BY FAR THE FURTHEST WEST OF
THE MODELS REGARDING SANDY 00Z MONDAY...AND THE EURO BRINGS LOW QPF
AS FAR EAST AS RANDOLPH COUNTY. THE OTHER MODELS...ESPECIALLY THE
12Z GFS...ARE MUCH FURTHER NORTHEAST WITH SANDY AND HAVE THE QPF
WELL EAST OF OUR COUNTY WARNING AREA. ALTHOUGH...HPC AND THE
HURRICANE CENTER`S OFFICIAL FORECAST SIDE WITH THE EURO...HAVE TO
LEND AT LEAST SMALL CREDENCE TO THE OTHER MODELS AND KEEP POPS OUT
OF OUR EAST FOR NOW ON MONDAY. TEMPERATURES WILL CONTINUE TO BE WELL
BELOW NORMAL DESPITE PLENTY OF SUNSHINE AS NORTHWEST WINDS TO NEAR
15 KNOTS AND GUSTS TO NEAR 20 KNOTS ARE EXPECTED.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
ISSUED AT 252 PM EDT FRI OCT 26 2012
THE LONG TERM STARTS WITH A LARGE UPPER RIDGE OVER THE WESTERN AND
CENTRAL U.S. AND A STRONG UPPER LOW /SANDY/ OFF THE EAST COAST.
THERE ARE DISCREPANCIES WITH THE HANDLING OF SANDY IN THE MODELS AND
THIS WILL IMPACT THE FORECAST HERE. THE ECMWF BRINGS THE SYSTEM
FURTHER WEST AND WOULD BRING RAIN TO THE EASTERN COUNTIES AND
PERHAPS TO THE ENTIRE AREA AS EARLY AS TUESDAY AND CONTINUING
THROUGH WEDNESDAY. THE GFS KEEPS THE SYSTEM MORE TO THE EAST AND
ONLY BRINGS IN A LITTLE RAIN IN THE NORTHEAST ON WEDNESDAY. GFS
SURFACE TEMPERATURES ARE ALSO COLDER. ENSEMBLES ARE LITTLE HELP WITH
QUITE A BIT OF VARIABILITY IN THE SOLUTIONS. THINK BEST COURSE OF
ACTION AT THIS POINT IS TO LEAVE THE ALLBLEND POPS ALONE EXCEPT FOR
MINOR TWEAKING LIKE REMOVING SMALL SLIGHT CHANCES IN THE NORTHEAST
MONDAY NIGHT AND THURSDAY. IF PRECIPITATION OCCURS BEFORE WEDNESDAY
A LA THE ECM TEMPERATURES COULD BE WARM ENOUGH FOR ALL RAIN...BUT
GFS TEMPERATURES ARE QUITE A BIT COOLER AND AFTER COLLABORATION
NECESSITATE THE INCLUSION OF A RAIN SNOW MIX. NO ACCUMULATION IS
EXPECTED IF FLAKES OCCUR.
&&
.AVIATION /DISCUSSION FOR 270000Z TAF ISSUANCE/...
ISSUED AT 709 PM EDT FRI OCT 26 2012
WITH EXCEPTION OF BRIEF MVFR CEILINGS THIS EVENING AT KBMG...VFR
CONDITIONS ANTICIPATED THROUGHOUT THE FORECAST PERIOD.
LOW LEVEL MOISTURE AND LIGHT RAIN CONTINUES TO SLOWLY PULL AWAY TO
THE EAST. DRIER AIR WILL FILTER INTO THE REGION OVERNIGHT AS A
LARGE HIGH PRESSURE RIDGE EXPANDS INTO THE LOWER OHIO VALLEY.
MODEL SOUNDINGS AND RAP LOW LEVEL RH PROGS SHOWING BACK EDGE OF
DEEPEST MOISTURE WILL REMAIN ACROSS EASTERN INDIANA TONIGHT...AND
MAY ACTUALLY SLIP BACK INTO KBMG AND KIND. CONFIDENCE IS LOW IN
THIS POSSIBILITY AT THIS POINT...BUT WILL KEEP A FEW-SCT MENTION
OF 3-4KFT STRATOCU AT BOTH SITES ALL NIGHT. HIGH CLOUDS WILL
BECOME THE PREDOMINANT CEILING AT BOTH KHUF AND KLAF OVERNIGHT.
NORTHERLY FLOW AROUND 10KTS WILL CONTINUE OVERNIGHT.
DRIER AIR AND DEEPER SUBSIDENCE ASSOCIATED WITH THE HIGH WILL
BUILD ACROSS CENTRAL INDIANA SATURDAY WITH ABUNDANT SUNSHINE
EXPECTED. MAY SEE DIURNAL CU DURING THE AFTERNOON AT ALL TERMINALS
IN A COLD ADVECTION PATTERN. NORTHERLY WINDS WILL GUST TO 20-25KTS
DURING THE AFTERNOON AS LOWER LEVEL BECOME WELL MIXED.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...MK
NEAR TERM...NIELD
SHORT TERM...MK
LONG TERM....CP
AVIATION...RYAN
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
709 PM EDT FRI OCT 26 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 252 PM EDT FRI OCT 26 2012
THE SHOWERS WILL BE ENDING ACROSS SOUTHEASTERN AND EAST CENTRAL
PARTS OF CENTRAL INDIANA AROUND SUNRISE AS A COLD FRONT STALLS
ACROSS THE APPALACHIANS. AFTER THAT...EXPECT WELL BELOW NORMAL
TEMPERATURES TO CONTINUE THROUGH NEXT WEEK AS HIGH PRESSURE SETTLES
IN ACROSS THE MISSISSIPPI AND WABASH VALLEYS. IT WILL BE MOSTLY
DRY...HOWEVER THERE IS A CHANCE OF SHOWERS ACROSS ALL BUT SOUTHWEST
PARTS OF CENTRAL INDIANA TUESDAY THROUGH WEDNESDAY ASSOCIATED WITH
SANDY. THE RAIN SHOWERS COULD MIX WITH SNOW TUESDAY NIGHT.
AFTERNOON HIGHS THROUGH NEXT WEEK WILL ONLY BE IN THE 40S AND
50S...WHILE OVERNIGHT LOWS WILL BE IN THE 30S.
&&
.NEAR TERM /TONIGHT/...
ISSUED AT 252 PM EDT FRI OCT 26 2012
MAIN CHALLENGE TO THE NEAR TERM WILL BE POPS AS THE AFOREMENTIONED
COLD FRONT IS EXPECTED TO STALL ACROSS THE APPALACHIANS IN RESPONSE
TO SANDY SHADOWING THE EASTERN COAST.
THE 00Z ECMWF WAS THE QUICKEST TO END QPF TONIGHT FOLLOWED BY THE
12Z RUNS OF THE GFS...NAM AND CANADIAN. PREFER TO USE THE NAM QPF
FIELD AS A CUTOFF FOR POPS AS IT MATCHES UP BEST WITH THE 13Z RAPID
REFRESH REFLECTIVITY PROG. HOWEVER...WILL GO SLIGHTLY WEST OF THAT
AS A BUFFER BUT NOT AS FAR WEST AS THE CANADIAN. THIS WOULD LEAVE
THE CUTOFF FOR POPS TONIGHT ALONG A LINE FROM ABOUT ANDERSON TO
BEECH GROVE TO LOOGOOTEE THROUGH 06Z AND FROM ABOUT MUNCIE TO
SEYMOUR FROM 06Z-12Z. POPS WILL TAPER FROM LIKELY SOUTHEAST TO
SLIGHT CHANCE FURTHER WEST THROUGH 06Z WITH JUST CHANCE POPS
THEREAFTER. ALSO...PARTIAL CLEARING WILL WORK ITS WAY EASTWARD
ACROSS THE FORECAST AREA AS HIGH PRESSURE MOVES INTO THE MISSISSIPPI
VALLEY. THIS SHOULD BRING TEMPERATURES TO NEAR FREEZING NORTHWEST
WITH THE REST OF THE FORECAST AREA ONLY EXPECTED TO GET DOWN TO THE
MID AND UPPER 30S WITH MORE CLOUD COVER PER SIMILAR MOS. ALLBLEND
LOOKS GOOD.
&&
.SHORT TERM /SATURDAY THROUGH MONDAY/...
ISSUED AT 252 PM EDT FRI OCT 26 2012
MAIN CHALLENGE TO THE SHORT TERM WILL BE WHETHER TO KEEP ANY MORNING
POPS IN ON SATURDAY AND THEN WHETHER OR NOT THE EAST SEES ANY SHOWER
ACTIVITY MONDAY FROM SANDY. TEMPERATURES AND POSSIBLE OVERNIGHT
FREEZING WILL ALSO BE A MAIN FOCUS.
AT THIS POINT...ALL THE 12Z MODEL RUNS AND THE 00Z ECMWF SUGGEST THE
SHOWERS WILL BE JUST EAST OF EAST CENTRAL INDIANA BY 12Z SATURDAY
WITH DECREASING CLOUD COVER. ALTHOUGH CLOUD COVER WILL BE ON THE LOW
SIDE...NORTH AND NORTHEAST WINDS TO AROUND 15 MPH AND GUSTING TO
AROUND 20 WILL KEEP TEMPERATURES DOWN TOWARDS THE COOLER GFS MOS IN
THE LOWER 50S FOR AFTERNOON HIGHS. MODELS ARE ALL BRINGING SOME HIGH
CLOUDS IN SATURDAY NIGHT AHEAD OF AN UPPER TROUGH. HOWEVER...WITH
THE NORTH WINDS CONTINUING AT 5 TO 10 MPH...TEMPERATURES NEAR
FREEZING PER SIMILAR MOS LOOK GOOD. NOT ENOUGH CONFIDENCE IN
WIDESPREAD FREEZING AT THIS TIME TO ISSUE ANY HEADLINES FOR OUR
SOUTHERN TWO TIERS...WHERE THEY HAVE YET TO HAVE A HARD FREEZE THIS
FALL. SUNDAY SHOULD BE NEAR A CARBON COPY OF SATURDAY EXCEPT
SLIGHTLY COOLER STILL WITH JUST SOME HIGH CLOUDS AND NORTH WINDS
CONTINUING NEAR 15 MPH WITH GUSTS TO NEAR 20. 850 MILLIBAR
TEMPERATURES COOL A COUPLE OF DEGREES TO -2 TO -4 DEGREES CELSIUS
LATE SUNDAY WHICH SHOULD RESULT IN AFTERNOON HIGHS ONLY IN THE UPPER
40S TO LOWER 50S PER THE COOLER 12Z GFS MOS AND ALLBLEND. SUNDAY
NIGHT...MODELS AGREE ON A DRY COLUMN WITH SOME LIGHTER NORTH AND
NORTHWEST WINDS WHICH SHOULD ALLOW FOR TEMPERATURES A COUPLE OF
DEGREES COLDER SUNDAY NIGHT THAN SATURDAY NIGHT. MOST AREAS WILL
SHOULD SEE TEMPERATURES RIGHT AROUND THE FREEZING MARK...SO COULD
VERY WELL SEE HEADLINES FOR OUR SOUTHERN COUNTIES...BUT FOR NOW A
BIT EARLY. FINALLY...THE 00Z ECMWF WAS BY FAR THE FURTHEST WEST OF
THE MODELS REGARDING SANDY 00Z MONDAY...AND THE EURO BRINGS LOW QPF
AS FAR EAST AS RANDOLPH COUNTY. THE OTHER MODELS...ESPECIALLY THE
12Z GFS...ARE MUCH FURTHER NORTHEAST WITH SANDY AND HAVE THE QPF
WELL EAST OF OUR COUNTY WARNING AREA. ALTHOUGH...HPC AND THE
HURRICANE CENTER`S OFFICIAL FORECAST SIDE WITH THE EURO...HAVE TO
LEND AT LEAST SMALL CREDENCE TO THE OTHER MODELS AND KEEP POPS OUT
OF OUR EAST FOR NOW ON MONDAY. TEMPERATURES WILL CONTINUE TO BE WELL
BELOW NORMAL DESPITE PLENTY OF SUNSHINE AS NORTHWEST WINDS TO NEAR
15 KNOTS AND GUSTS TO NEAR 20 KNOTS ARE EXPECTED.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
ISSUED AT 252 PM EDT FRI OCT 26 2012
THE LONG TERM STARTS WITH A LARGE UPPER RIDGE OVER THE WESTERN AND
CENTRAL U.S. AND A STRONG UPPER LOW /SANDY/ OFF THE EAST COAST.
THERE ARE DISCREPANCIES WITH THE HANDLING OF SANDY IN THE MODELS AND
THIS WILL IMPACT THE FORECAST HERE. THE ECMWF BRINGS THE SYSTEM
FURTHER WEST AND WOULD BRING RAIN TO THE EASTERN COUNTIES AND
PERHAPS TO THE ENTIRE AREA AS EARLY AS TUESDAY AND CONTINUING
THROUGH WEDNESDAY. THE GFS KEEPS THE SYSTEM MORE TO THE EAST AND
ONLY BRINGS IN A LITTLE RAIN IN THE NORTHEAST ON WEDNESDAY. GFS
SURFACE TEMPERATURES ARE ALSO COLDER. ENSEMBLES ARE LITTLE HELP WITH
QUITE A BIT OF VARIABILITY IN THE SOLUTIONS. THINK BEST COURSE OF
ACTION AT THIS POINT IS TO LEAVE THE ALLBLEND POPS ALONE EXCEPT FOR
MINOR TWEAKING LIKE REMOVING SMALL SLIGHT CHANCES IN THE NORTHEAST
MONDAY NIGHT AND THURSDAY. IF PRECIPITATION OCCURS BEFORE WEDNESDAY
A LA THE ECM TEMPERATURES COULD BE WARM ENOUGH FOR ALL RAIN...BUT
GFS TEMPERATURES ARE QUITE A BIT COOLER AND AFTER COLLABORATION
NECESSITATE THE INCLUSION OF A RAIN SNOW MIX. NO ACCUMULATION IS
EXPECTED IF FLAKES OCCUR.
&&
.AVIATION /DISCUSSION FOR 270000Z TAF ISSUANCE/...
ISSUED AT 709 PM EDT FRI OCT 26 2012
WITH EXCEPTION OF BRIEF MVFR CEILINGS THIS EVENING AT KBMG...VFR
CONDITIONS ANTICIPATED THROUGHOUT THE FORECAST PERIOD.
LOW LEVEL MOISTURE AND LIGHT RAIN CONTINUES TO SLOWLY PULL AWAY TO
THE EAST. DRIER AIR WILL FILTER INTO THE REGION OVERNIGHT AS A
LARGE HIGH PRESSURE RIDGE EXPANDS INTO THE LOWER OHIO VALLEY.
MODEL SOUNDINGS AND RAP LOW LEVEL RH PROGS SHOWING BACK EDGE OF
DEEPEST MOISTURE WILL REMAIN ACROSS EASTERN INDIANA TONIGHT...AND
MAY ACTUALLY SLIP BACK INTO KBMG AND KIND. CONFIDENCE IS LOW IN
THIS POSSIBILITY AT THIS POINT...BUT WILL KEEP A FEW-SCT MENTION
OF 3-4KFT STRATOCU AT BOTH SITES ALL NIGHT. HIGH CLOUDS WILL
BECOME THE PREDOMINANT CEILING AT BOTH KHUF AND KLAF OVERNIGHT.
NORTHERLY FLOW AROUND 10KTS WILL CONTINUE OVERNIGHT.
DRIER AIR AND DEEPER SUBSIDENCE ASSOCIATED WITH THE HIGH WILL
BUILD ACROSS CENTRAL INDIANA SATURDAY WITH ABUNDANT SUNSHINE
EXPECTED. MAY SEE DIURNAL CU DURING THE AFTERNOON AT ALL TERMINALS
IN A COLD ADVECTION PATTERN. NORTHERLY WINDS WILL GUST TO 20-25KTS
DURING THE AFTERNOON AS LOWER LEVEL BECOME WELL MIXED.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MK
NEAR TERM...MK
SHORT TERM...MK
LONG TERM....CP
AVIATION...RYAN
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
201 PM EDT THU OCT 25 2012
.AVIATION...
18Z TAFS...SOUTH WINDS OF 15 TO 25 KNOTS WITH GUSTS TO 30 KNOTS
WILL CONTINUE THROUGH THE REMAINDER OF THE AFTERNOON WITH PEAK
MIXING. SOME DIMINISHMENT IN GUSTS INTO THE 20 TO 25 KNOT RANGE IS
EXPECTED THIS EVENING WITH LOSS OF DEEPER MIXING. SOME DRIER LOW
LEVEL AIR WHICH HAS ADVECTED IN FROM THE SOUTH WILL CAP ANY
CONVECTIVE ACTIVITY THIS AFTERNOON. TOWARD EVENING...LOW LEVEL
MOISTURE IS EXPECTED TO INCREASE AGAIN IN ADVANCE OF A COLD FRONT
ACROSS NORTHWEST ILLINOIS. A FEW ISOLATED SHOWERS OR STORMS ARE
POSSIBLE ALONG THE COLD FRONT...WITH A BETTER CHANCE OF MORE
WIDESPREAD RAIN SHOWERS DEVELOPING BEHIND THE FRONT LATE THIS
EVENING AT KSBN...AND FOR THE OVERNIGHT HOURS AT KFWA. BEST
ELEVATED INSTABILITY IS EXPECTED AT KSBN IN THE 03Z TO 06Z
TIMEFRAME...WHEN HAVE MAINTAINED VCTS MENTION. WINDS TO SHIFT
NORTHWEST BEHIND THE FRONT TONIGHT...WITH A PERIOD OF LOWER END
MVFR CONDITIONS EXPECTED BEHIND THE FRONT TONIGHT BEFORE CIGS MVFR
CIGS ARE EXPECTED TO IMPROVE ABOVE 2K FT FRIDAY MORNING AS DRIER
LOW LEVEL AIR ADVECTS IN. RAIN SHOWERS TO PERSIST AT KFWA THROUGH
LATE MORNING AS MID LEVEL FRONTAL ZONE IS SLOW TO PUSH OFF TO THE
EAST.
&&
.PREV DISCUSSION... /ISSUED 1132 AM EDT THU OCT 25 2012/
UPDATE...
ONLY TWEAK TO PREVIOUS GRIDS WAS TO ADJUST HOURLY TEMPERATURE
TRENDS MAINLY FOR THIS EVENING BASED ON UPSTREAM OBSERVATIONS IN
ASSOCIATION THE COLD FRONT PASSAGE. TRIED TO INCORPORATE A
NAM12/PREVIOUS FORECAST BLEND TO SHOW A BIT SHARPER OF A TEMP/DEW
POINT DROP OFF WITH FRONT. OTHERWISE...OTHER FORECAST ELEMENTS FOR
PERIOD ONE STILL APPEAR TO BE ON TRACK WITH HIGHS IN THE MID TO
UPPER 70S. HRRR HINTING AT SOME CONVECTIVE DEVELOPMENT ALONG THE
COLD FRONT ACROSS NORTHWEST INDIANA THIS EVENING...BUT STILL
SOMEWHAT SUSPICIOUS OF THIS SOLUTION WITH INSTABILITY EXPECTED TO
BE FAIRLY LIMITED UNTIL BECOMING MORE ELEVATED IN NATURE BEHIND THE
FRONT.
MARINE...
SOUTH WINDS WILL CONTINUE TO INCREASE THIS AFTERNOON WITH LATEST
MICHIGAN CITY OBSERVATIONS ALREADY INDICATING SOUTH GUSTS INTO
THE 25 TO 30 KNOT RANGE. CANNOT COMPLETELY RULE OUT A FEW GUSTS TO
NEAR GALES THIS AFTERNOON. OF GREATER CONCERN IS EARLY THIS
EVENING IN ASSOCIATION WITH THE FRONTAL PASSAGE. A NARROW BUT
STRONG CORRIDOR OF SURFACE PRESSURE RISES BEHIND THE FRONT SHOULD
INDUCE A PERIOD OF WEST GUSTS TO NEAR GALES THIS
EVENING...ESPECIALLY IN THE 00Z TO 04Z TIMEFRAME. HAVE HELD OFF ON
ANY UPGRADED HEADLINES AT THIS TIME...BUT WILL NEED TO CONSIDER AT
LEAST MENTION OF A FEW GUSTS TO GALE FORCE IN POSSIBLE NEARSHORE
FORECAST AMENDMENTS THIS AFTERNOON.
PREV DISCUSSION... /ISSUED 703 AM EDT THU OCT 25 2012/
AVIATION.../12Z TAFS/
DVLPG SFC LOW ALONG STNRY FRONT OVER NE IA THIS MORNING WILL
DEEPEN/INTENSIFY AS IT LIFTS NE TODAY CAUSING STNRY FRONT TO SURGE
EASTWARD AS A CDFNT. STRONG SWLY WIND FIELD IN PLACE OVER THE AREA
ATTM WITH KIWX VWP INDICATING 40KT IN LOWEST GATE AT 2KFT. THESE
STRONG WINDS WILL MIX DOWN DURING THE DAY WITH SFC GUSTS 27-32KT
EXPECTED... HIGHEST AT SBN. OTRWS... VFR CONDITIONS THROUGH THE
DAY WITH JUST SCT CU.
CDFNT EXPECTED TO MOVE THROUGH SBN BY 04Z AND FWA BY 08Z FOLLOWED
BY A PERIOD OF SHOWERS WITH AVIATION CONDITIONS LOWERING AT LEAST
TO MVFR AND PSBLY IFR. INSTABILITY WILL BE LIMITED BUT PRBLY
SUFFICIENT FOR A FEW TSTMS AS FAR EAST AS NWRN INDIANA SO INCLUDED
VCTS IN SBN TAF. WNDSHFT ON CDFNT WILL BE ABRUPT FROM SW-NW WITH
STRONG LOW LEVEL CAA PROMOTING POST FRONTAL GUSTS THROUGH THE
NIGHT.
PREV DISCUSSION... /ISSUED 410 AM EDT THU OCT 25 2012/
SHORT TERM...
TODAY THROUGH FRIDAY NIGHT...
THE FORECAST CHALLENGES THIS PERIOD INCLUDE THE CHANCES FOR A RECORD
HIGH TEMPERATURE AT SOUTH BEND TODAY AND THE TIMING OF A STRONG COLD
FRONT THURSDAY NIGHT ALONG WITH ASSOCIATED PRECIPITATION. HIGHS
WEDNESDAY WERE RATHER UNIFORM AROUND 78F DEGREES. ALTHOUGH A WARM
AND MOIST FLOW SHOULD CONTINUE FROM THE SOUTH AND SOUTHWEST TODAY...
SOMEWHAT COOLER AIR UNDER 925 MB SHOULD SPREAD INTO THE REGION IN
THE LOW LEVELS. HAVE KEPT HIGHS A LITTLE LOWER THAN YESTERDAY...
GENERALLY 75 TO 77 DEGREES...WHICH SHOULD KEEP THE TEMPERATURE BELOW
THE RECORD HIGH OF 80 DEGREES AT SOUTH BEND. A STRONG COLD FRONT WILL
MOVE ACROSS THE FORECAST AREA THURSDAY NIGHT. SOME QUESTION WHETHER
EARLY STORMS WILL BE SURFACE BASED...INCREASING THE RISK FOR SEVERE
STORMS WITH HIGH WINDS GIVEN MOMENTUM TRANSFER OF 50 TO 55 KNOTS IN
THE 925/850 MB LEVEL. HOWEVER..THE SUBSIDENCE INVERSION AND MID
LEVEL WARMING HAS INCREASED SIGNIFICANTLY UPSTREAM AS INDICATED ON
THE LINCOLN RAOB. CURRENT THINKING IS THAT ANY STORMS WILL BE
ELEVATED AND WILL BE POST FRONTAL...LIMITING GREATLY SEVERE WEATHER
POTENTIAL. GIVEN THE STRENGTH OF THE FRONT WHICH INCLUDES ABOUT A 25
DEGREE TEMPERATURE DROP IN THE FIRST 100 MILES...TEMPERATURES WILL
DROP TO BETWEEN 41F AND 43F OVER FAR SW AND WEST AREA. LASTLY...KEPT
LAKE EFFECT/LAKE ENHANCED SHOWERS OUT. WINDS VEER TOO FAR TO THE
NORTHEAST FRI NGT.
LONG TERM.../SAT-WED/
UPR LEVEL TROF OVER THE ROCKIES THIS MORNING WILL MOVE EAST TO THE
MS VALLEY AND DEEPEN A BIT BY SAT AS A SERIES OF MID LEVEL SHRTWVS
MOVE THROUGH THE BASE OF THE TROF. MODELS HAVE TRENDED A LITTLE
FASTER WITH SHRTWV EXPECTED TO MOVE THROUGH OUR AREA SAT... THUS
HAVE LOWERED POPS IN THIS PERIOD...ESPECIALLY IN THE AFTN.
MEDIUM RANGE MODELS HANDLING OF THE TROF MOVG INTO THE GRTLKS AND
ITS INTERACTION WITH WRN ATLANTIC HURRICANE SANDY HAS BEEN
ERRATIC... BUT THERE IS FAIR AGREEMENT ON 00Z RUNS THAT A RATHER
DEEP CLOSED/STACKED LOW WILL FORM OR MOVE INTO THE LWR GRTLKS EARLY
NEXT WEEK WITH IMPLICATION THAT WRN FRINGE OF ITS PRECIP SHIELD
AND/OR LAKE EFFECT OFF LAKE MICHIGAN WITH N-NW LOW LEVEL FLOW WOULD
IMPACT OUR AREA. STILL PLENTY OF UNCERTAINTY GIVEN POOR RUN-RUN
MODEL CONTINUITY AND CONSIDERABLE DIFFERENCES AMONG VARIOUS MODELS
ON DETAILS/EVOLUTION OF THE LOW... THUS BLEND OF MODELS AND PREVIOUS
FCST YIELDING JUST SLIGHT CHC POPS WAS FOLLOWED WITH ONLY COSMETIC
ADJUSTMENTS FOR DAYS6-7.
WITH LITTLE MOVEMENT AND GRADUAL DEEPENING OF UPR TROF OVER THE
GRTLKS THROUGH THE LONG TERM PERIOD... TEMPS SHOULD BE BLO NORMAL
WITH LITTLE DAILY CHANGE IN HIGHS/LOWS. FCST HIGHS GENERALLY IN THE
M-U40S AND LOWS IN THE L-M30S EACH DAY.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 6 AM EDT SATURDAY FOR LMZ043-046.
&&
$$
SHORT TERM...SKIPPER
LONG TERM...JT
AVIATION...MARSILI
UPDATE...MARSILI
MARINE...MARSILI
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
1132 AM EDT THU OCT 25 2012
.UPDATE...
ONLY TWEAK TO PREVIOUS GRIDS WAS TO ADJUST HOURLY TEMPERATURE
TRENDS MAINLY FOR THIS EVENING BASED ON UPSTREAM OBSERVATIONS IN
ASSOCIATION THE COLD FRONT PASSAGE. TRIED TO INCORPORATE A
NAM12/PREVIOUS FORECAST BLEND TO SHOW A BIT SHARPER OF A TEMP/DEW
POINT DROP OFF WITH FRONT. OTHERWISE...OTHER FORECAST ELEMENTS FOR
PERIOD ONE STILL APPEAR TO BE ON TRACK WITH HIGHS IN THE MID TO
UPPER 70S. HRRR HINTING AT SOME CONVECTIVE DEVELOPMENT ALONG THE
COLD FRONT ACROSS NORTHWEST INDIANA THIS EVENING...BUT STILL
SOMEWHAT SUSPICIOUS OF THIS SOLUTION WITH INSTABILITY EXPECTED TO
BE FAIRLY LIMITED UNTIL BECOMING MORE ELEVATED IN NATURE BEHIND THE
FRONT.
&&
.MARINE...
SOUTH WINDS WILL CONTINUE TO INCREASE THIS AFTERNOON WITH LATEST
MICHIGAN CITY OBSERVATIONS ALREADY INDICATING SOUTH GUSTS INTO
THE 25 TO 30 KNOT RANGE. CANNOT COMPLETELY RULE OUT A FEW GUSTS TO
NEAR GALES THIS AFTERNOON. OF GREATER CONCERN IS EARLY THIS
EVENING IN ASSOCIATION WITH THE FRONTAL PASSAGE. A NARROW BUT
STRONG CORRIDOR OF SURFACE PRESSURE RISES BEHIND THE FRONT SHOULD
INDUCE A PERIOD OF WEST GUSTS TO NEAR GALES THIS
EVENING...ESPECIALLY IN THE 00Z TO 04Z TIMEFRAME. HAVE HELD OFF ON
ANY UPGRADED HEADLINES AT THIS TIME...BUT WILL NEED TO CONSIDER AT
LEAST MENTION OF A FEW GUSTS TO GALE FORCE IN POSSIBLE NEARSHORE
FORECAST AMENDMENTS THIS AFTERNOON.
&&
.PREV DISCUSSION... /ISSUED 703 AM EDT THU OCT 25 2012/
AVIATION.../12Z TAFS/
DVLPG SFC LOW ALONG STNRY FRONT OVER NE IA THIS MORNING WILL
DEEPEN/INTENSIFY AS IT LIFTS NE TODAY CAUSING STNRY FRONT TO SURGE
EASTWARD AS A CDFNT. STRONG SWLY WIND FIELD IN PLACE OVER THE AREA
ATTM WITH KIWX VWP INDICATING 40KT IN LOWEST GATE AT 2KFT. THESE
STRONG WINDS WILL MIX DOWN DURING THE DAY WITH SFC GUSTS 27-32KT
EXPECTED... HIGHEST AT SBN. OTRWS... VFR CONDITIONS THROUGH THE
DAY WITH JUST SCT CU.
CDFNT EXPECTED TO MOVE THROUGH SBN BY 04Z AND FWA BY 08Z FOLLOWED
BY A PERIOD OF SHOWERS WITH AVIATION CONDITIONS LOWERING AT LEAST
TO MVFR AND PSBLY IFR. INSTABILITY WILL BE LIMITED BUT PRBLY
SUFFICIENT FOR A FEW TSTMS AS FAR EAST AS NWRN INDIANA SO INCLUDED
VCTS IN SBN TAF. WNDSHFT ON CDFNT WILL BE ABRUPT FROM SW-NW WITH
STRONG LOW LEVEL CAA PROMOTING POST FRONTAL GUSTS THROUGH THE
NIGHT.
PREV DISCUSSION... /ISSUED 410 AM EDT THU OCT 25 2012/
SHORT TERM...
TODAY THROUGH FRIDAY NIGHT...
THE FORECAST CHALLENGES THIS PERIOD INCLUDE THE CHANCES FOR A RECORD
HIGH TEMPERATURE AT SOUTH BEND TODAY AND THE TIMING OF A STRONG COLD
FRONT THURSDAY NIGHT ALONG WITH ASSOCIATED PRECIPITATION. HIGHS
WEDNESDAY WERE RATHER UNIFORM AROUND 78F DEGREES. ALTHOUGH A WARM
AND MOIST FLOW SHOULD CONTINUE FROM THE SOUTH AND SOUTHWEST TODAY...
SOMEWHAT COOLER AIR UNDER 925 MB SHOULD SPREAD INTO THE REGION IN
THE LOW LEVELS. HAVE KEPT HIGHS A LITTLE LOWER THAN YESTERDAY...
GENERALLY 75 TO 77 DEGREES...WHICH SHOULD KEEP THE TEMPERATURE BELOW
THE RECORD HIGH OF 80 DEGREES AT SOUTH BEND. A STRONG COLD FRONT WILL
MOVE ACROSS THE FORECAST AREA THURSDAY NIGHT. SOME QUESTION WHETHER
EARLY STORMS WILL BE SURFACE BASED...INCREASING THE RISK FOR SEVERE
STORMS WITH HIGH WINDS GIVEN MOMENTUM TRANSFER OF 50 TO 55 KNOTS IN
THE 925/850 MB LEVEL. HOWEVER..THE SUBSIDENCE INVERSION AND MID
LEVEL WARMING HAS INCREASED SIGNIFICANTLY UPSTREAM AS INDICATED ON
THE LINCOLN RAOB. CURRENT THINKING IS THAT ANY STORMS WILL BE
ELEVATED AND WILL BE POST FRONTAL...LIMITING GREATLY SEVERE WEATHER
POTENTIAL. GIVEN THE STRENGTH OF THE FRONT WHICH INCLUDES ABOUT A 25
DEGREE TEMPERATURE DROP IN THE FIRST 100 MILES...TEMPERATURES WILL
DROP TO BETWEEN 41F AND 43F OVER FAR SW AND WEST AREA. LASTLY...KEPT
LAKE EFFECT/LAKE ENHANCED SHOWERS OUT. WINDS VEER TOO FAR TO THE
NORTHEAST FRI NGT.
LONG TERM.../SAT-WED/
UPR LEVEL TROF OVER THE ROCKIES THIS MORNING WILL MOVE EAST TO THE
MS VALLEY AND DEEPEN A BIT BY SAT AS A SERIES OF MID LEVEL SHRTWVS
MOVE THROUGH THE BASE OF THE TROF. MODELS HAVE TRENDED A LITTLE
FASTER WITH SHRTWV EXPECTED TO MOVE THROUGH OUR AREA SAT... THUS
HAVE LOWERED POPS IN THIS PERIOD...ESPECIALLY IN THE AFTN.
MEDIUM RANGE MODELS HANDLING OF THE TROF MOVG INTO THE GRTLKS AND
ITS INTERACTION WITH WRN ATLANTIC HURRICANE SANDY HAS BEEN
ERRATIC... BUT THERE IS FAIR AGREEMENT ON 00Z RUNS THAT A RATHER
DEEP CLOSED/STACKED LOW WILL FORM OR MOVE INTO THE LWR GRTLKS EARLY
NEXT WEEK WITH IMPLICATION THAT WRN FRINGE OF ITS PRECIP SHIELD
AND/OR LAKE EFFECT OFF LAKE MICHIGAN WITH N-NW LOW LEVEL FLOW WOULD
IMPACT OUR AREA. STILL PLENTY OF UNCERTAINTY GIVEN POOR RUN-RUN
MODEL CONTINUITY AND CONSIDERABLE DIFFERENCES AMONG VARIOUS MODELS
ON DETAILS/EVOLUTION OF THE LOW... THUS BLEND OF MODELS AND PREVIOUS
FCST YIELDING JUST SLIGHT CHC POPS WAS FOLLOWED WITH ONLY COSMETIC
ADJUSTMENTS FOR DAYS6-7.
WITH LITTLE MOVEMENT AND GRADUAL DEEPENING OF UPR TROF OVER THE
GRTLKS THROUGH THE LONG TERM PERIOD... TEMPS SHOULD BE BLO NORMAL
WITH LITTLE DAILY CHANGE IN HIGHS/LOWS. FCST HIGHS GENERALLY IN THE
M-U40S AND LOWS IN THE L-M30S EACH DAY.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 6 AM EDT SATURDAY FOR LMZ043-046.
&&
$$
SHORT TERM...SKIPPER
LONG TERM...JT
AVIATION...JT
UPDATE...MARSILI
MARINE...MARSILI
AREA FORECAST DISCUSSION
NWS DES MOINES IA
647 PM CDT FRI OCT 26 2012
...UPDATED FOR 27/00Z AVIATION DISCUSSION...
.SHORT TERM /TONIGHT/...
HIGH PRESSURE CURRENTLY CENTERED OVER SW NE AND NW KS WILL TRANSLATE
EASTWARD TONIGHT. THIS WILL ALLOW WINDS TO DIMINISH WITH SUNSET.
STRATUS DECK THAT HAS BEEN IN PLACE MUCH OF THE DAY HAS BECOME MORE
CELLULAR ON THE SOUTH/EASTERN EDGES AND EXPECT THAT AREA AND POINTS
FURTHER SOUTH/EAST IN THE CWA TO CLEAR OFF OVERNIGHT. MODELS HAVE
BEEN HAVING A HARD TIME DEALING WITH THIS LOWER LEVEL MOISTURE THAT
IS TRAPPED BELOW THE INVERSION. THEREFORE TEMPERATURES A BIT TRICKY
TONIGHT DUE TO UNCERTAINTY WITH THE CLOUD COVER. RAP MODEL SEEMED TO
BE LINING UP THE BEST WITH ITS 925-850MB RH FIELD...THEREFORE
TRENDED SKY COVER TOWARD THAT MODEL. THIS SOLUTION ALSO SUGGESTS THE
CLEARING IN THE AFOREMENTIONED AREAS AND THE LOWER CLOUDS LINGERING
ACROSS THE WEST CENTRAL/NORTHWESTERN CWA THROUGH THE NIGHT.
THEREFORE HAVE KEPT TEMPS A LITTLE WARMER DUE TO THE CLOUD
COVER...BUT STILL A LITTLE COOLER FROM READINGS LAST NIGHT DUE TO
THE UNCERTAINTY WITH THE CLOUD COVER.
.LONG TERM /SATURDAY THROUGH FRIDAY/...
WITH ALL EYES ON THE EAST COAST AND EVOLUTION OF SANDY...IA WEATHER
WILL BE TRANQUIL WITH SEASONALLY COOL TEMPERATURES. ONLY NEAR TERM
WINDOW FOR PRECIP WILL BE WITH SHORT WAVE CURRENTLY OFF BC COAST
WHICH DROPS INTO MO VALLEY SAT NIGHT. MODELS HAVE TRENDED SLIGHTLY
NORTH AND WEST WITH ITS FORCING AND MOISTURE SO HAVE REMOVED
MEASURABLE POPS WITH NOTHING BEYOND FLURRY WORDING FAR NW 09-15Z SAT.
A SIMILAR SHORT WAVE EJECTING OUT OF THE PACIFIC NW THIS WEEKEND
WILL DROP INTO THE BASE OF THE MS/OH VALLEY LONG WAVE TROUGH AND
EVENTUALLY PHASE WITH SANDY. THIS IMPRESSIVE STORM...WHERE EVER ITS
LOCATION AND LANDFALL...WILL BE SLOW MOVING AND LOCK IN OUR PATTERN
KEEPING IA IN PERSISTENT RELATIVELY DRY NW FLOW AND NEAR NORMAL
TEMPERATURES. ALTHOUGH CONFIDENCE AND MODEL CONSENSUS IS NOT GREAT
ENOUGH TO INTRODUCE MEASURABLE POPS AT THIS POINT...TOKEN PRECIP
MENTION MAY EVENTUALLY BE NEEDED AROUND MON OR TUE...AND AGAIN
AROUND THU. TEMPERATURES WILL BE FAIRLY STEADY THROUGH THE ENTIRE
PERIOD WITH GENERALLY LIGHT WINDS AND LITTLE CHANGE IN AIRMASS.
&&
.AVIATION...27/00Z
LOW VFR STRATUS DECK CONTINUES TO SLOWLY EXPAND SOUTHEAST THIS
EVENING...WHICH WILL MAINLY AFFECT KFOD/KMCW/KDSM/KALO OVERNIGHT.
AS THE SURFACE HIGH MOVES IN AND THE BOUNDARY LAYER DECOUPLES...SEE
NO REASON WHY THIS DECK WILL NOT LOWER INTO HIGH END MVFR CATEGORY
AROUND FL030. HAVE INTRODUCED MVFR CIGS KMCW/KFOD THIS TAF ISSUANCE
AND WILL CONTINUE TO MONITOR TRENDS THE NEXT SEVERAL HOURS.
OTHERWISE...CIGS WILL RISE TO VFR BY MORNING AND WINDS WILL BE
RATHER LIGHT AND VARIABLE TOMORROW AS SURFACE HIGH SLIDES ACROSS THE
STATE.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...BEERENDS
LONG TERM...SMALL
AVIATION...DEITSCH
AREA FORECAST DISCUSSION...UPDATED
NWS TOPEKA KS
643 PM CDT FRI OCT 26 2012
...UPDATE TO AVIATION...
.DISCUSSION...
SHORT TERM FORECAST - TONIGHT AND SATURDAY...
AT 19Z RAP SURFACE ANALYSIS INDICATED A RIDGE OF HIGH PRESSURE
LOCATED ROUGHLY ACROSS WESTERN NEBRASKA AND WESTERN KANSAS...WITH
THE RIDGE AXIS RUNNING FROM KBBW SOUTHWESTWARD TO KGLD. ALONG THE
EASTERN EDGE OF THE AREA OF HIGH PRESSURE NORTHERLY WINDS CONTINUE
TO ALLOW COOLER AIR TO TRICKLE INTO EASTERN KANSAS. AS THE RIDGE
MOVES EASTWARD THE AXIS WILL BECOME CENTERED OVER THE FORECAST AREA
TONIGHT...WHICH WILL CAUSE WINDS TO BECOME CALM AND SKIES TO BECOME
MOSTLY CLEAR TO PARTLY CLOUDY. THE COMBINATION OF THE TWO EFFECTS
WILL BRING VERY CHILLY TEMPERATURES TO THE REGION FOR THE OVERNIGHT
HOURS. EXPECT TEMPS TO DROP INTO THE LOWER TO MID 20S ACROSS THE
ENTIRE AREA...WITH LOW LYING SUCH AS RIVER VALLEYS TO DROP INTO THE
UPPER TEENS TO LOWER 20S. AS THE SURFACE HIGH MOVES TO THE EAST
SOUTHERLY FLOW WILL GRADUALLY PICK UP ON THE BACK/WEST SIDE OF THE
DEPARTING RIDGE...WHICH WILL COMMENCE A SLOW WARM UP TREND...WHICH
WILL CONTINUE THROUGH THE WEEKEND. EXPECT HIGHS ON SATURDAY TO BE
SLIGHTLY WARMER THAN FRIDAY`S HIGHS...BUT WITH HIGH CLOUDS MOVING
THROUGH THE AMOUNT OF WARMING FOR SATURDAY WILL BE MARGINAL...SO
WILL EXPECT HIGHS TO GENERALLY BE IN THE LOWER TO MID 50S.
JL
LONG TERM - SATURDAY NIGHT THROUGH FRIDAY...
THE ENTIRE PERIOD IS FORECAST TO BE TRANQUIL AND ESSENTIALLY
PRECIPITATION FREE. NORTHWEST UPPER LEVEL FLOW WILL PERSIST ACROSS
THE REGION WITH INCREASED UPPER LEVEL RIDGING WITH TIME. MAY SEE
A FEW PERIODS OF INCREASED CLOUD COVER AS A SERIES OF VERY WEAK
DISTURBANCES MOVES THROUGH THE NORTHWEST FLOW BETWEEN NOW AND
WEDNESDAY...BUT NO PRECIPITATION IS EXPECTED WITH THESE SYSTEMS
GIVEN LACK OF MOISTURE AND ONLY WEAK ASCENT. EXPECT A GRADUAL WARM
UP WITH THE INCREASED RIDGING...PARTICULARLY DURING THE SECOND
HALF OF THE WEEK AS MODEL GUIDANCE IS CONSISTENT IN BRINGING A
FAIRLY STRONG SHORT WAVE TROUGH ACROSS THE ROCKIES BY NEXT
WEEKEND. ANY PRECIPITATION ASSOCIATED WITH THIS TROUGH WOULD
LIKELY HOLD OFF UNTIL FRIDAY NIGHT OR LATER...BUT WARMING
TEMPERATURES AND AN INCREASE IN LOW LEVEL MOISTURE IN ADVANCE OF
THE SYSTEM MAY BE NOTICED AS EARLY AS THURSDAY.
BARJENBRUCH
&&
.AVIATION...
THE CENTER OF A SFC HIGH PRESSURE RIDGE WILL PASS ACROSS THE TAF
SITES THROUGH SUNRISE WHICH WILL KEEP WINDS VERY LIGHT AND
GENERALLY FROM THE NORTH TO NORTHEAST...BECOMING
EAST/SOUTHEASTERLY AFT 15Z. APPEARS THERE WILL ENOUGH MIXING AND
DRY AIR OFF THE SFC TO LIMIT FOG POTENTIAL...SO WILL CONTINUE WITH
VFR CONDITIONS AND SCT-BKN AROUND 15KFT.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
620 PM CDT FRI OCT 26 2012
...UPDATED AVIATION SECTION...
.SHORT TERM...(THIS EVENING THROUGH TOMORROW)
ISSUED AT 302 PM CDT FRI OCT 26 2012
A FAST MOVING SHORTWAVE TROUGH WAS OVER EASTERN COLORADO AND WESTERN
KANSAS THIS MORNING. THIS SYSTEM BROUGHT SOME MEASURABLE SNOW TO FAR
WESTERN PORTIONS OF SOUTHWEST KANSAS. BY EARLY AFTERNOON THE
SHORTWAVE HAD MOVED INTO EASTERN KANSAS WITH CLEARING SKIES IN ITS
WAKE. THERE WAS SOME LINGERING STRATUS ALONG WITH LIGHT SNOW
FLURRIES OUT ALONG THE COLORADO BORDER BEING FORCED BY SOME WEAK PVA
AND LOW LEVEL UPSLOPE. RUC13 MODEL CROSS SECTIONS SHOW THIS AREA OF
CLOUDS/PRECIPITATION DECREASING THROUGH THE NEXT FEW HOURS. VISIBLE
SATELLITE LOOPS SHOW THE AREA OF STRATUS ALREADY STARTING TO
DIMINISH. SKIES SHOULD BE MOSTLY CLEAR ACROSS ALL OF SOUTHWEST
KANSAS BY THIS EVENING.
WITH THE COLD HIGH PRESSURE AIRMASS IN PLACE ACROSS WESTERN KANSAS,
CLEAR SKIES AND LIGHT WINDS THIS EVENING WILL RESULT IN TEMPERATURES
FALLING TO BELOW FREEZING FAIRLY SOON AFTER SUNSET. OVERNIGHT LOWS
WILL BE FALLING INTO THE LOWER TO MIDDLE 20S ACROSS THE ENTIRE AREA
OVERNIGHT. WITH THIS IN MIND, WILL CONVERT THE HARD FREEZE WATCH TO
A HARD FREEZE WARNING FOR THE AREA ALONG AND SOUTH OF A LINE FROM
JOHNSON TO JETMORE AND LARNED. THE AREA FROM SYRACUSE THROUGH
DIGHTON SAW A GOOD FREEZE LAST NIGHT SO THEY ARE DONE FOR THE YEAR
AS ARE AREAS UP TOWARD I-70. ANOTHER WEAK AND FAST MOVING SHORTWAVE
TROUGH WILL BE APPROACHING THE CENTRAL HIGH PLAINS LATER TONIGHT.
THIS COULD SPREAD SOME HIGH CLOUDINESS INTO PARTS OF WESTERN KANSAS.
IN ADDITION, THE SURFACE HIGH PRESSURE WILL BE MOVING INTO EASTERN
KANSAS LATER TONIGHT WHILE PRESSURE FALLS WILL ENSUE ALONG THE
EASTERN SLOPES OF THE ROCKIES. THIS COULD RESULT IN TEMPERATURES
RISING SOMEWHAT LATE TONIGHT.
SOUTHERLY WINDS WILL BECOME GUSTY FROM THE SOUTH ON SATURDAY AS THE
SURFACE PRESSURE GRADIENT INCREASES. ONLY SOME SCATTERED HIGH
CLOUDINESS IS EXPECTED DURING THE DAY. BASED ON MODEL 850
TEMPERATURE FORECASTS, HIGHS ON SATURDAY SHOULD ONLY CLIMB INTO THE
LOWER 50S IN MOST AREAS.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 321 PM CDT FRI OCT 26 2012
SOUTHERLY WINDS WILL BECOME ESTABLISHED BY OVERNIGHT SATURDAY, BUT
TEMPERATURES WILL LIKELY STILL FALL TO AROUND FREEZING WITH LIGHT
WINDS AND SUCH A DRY AIRMASS. THE ECMWF AND GFS ARE VERY SIMILAR IN
THE GENERAL MASS FIELDS FOR SUNDAY. SIMILARITIES ARE MOST
PRONOUNCED IN THE MID LEVEL RELATIVE HUMIDITY FIELDS, ASSOCIATED
WITH REMNANTS OF A NORTHERN PLAINS SHORTWAVE AND THE UPPER JET
DIVING THROUGH THE GREAT PLAINS FROM NORTH TO SOUTH. THIS COULD LEAD
TO CONSIDERABLE ALTOSTRATUS OR AT LEAST HIGH CIRRUS CLOUDS FOR
CENTRAL KANSAS FOR A GOOD PORTION OF THE DAY. THERMAL FIELDS DIFFER
CONSIDERABLE HOWEVER, ESPECIALLY WITH RESPECT TO HOW FAST THE GFS
WARMS THE BOUNDARY LAYER APPROXIMATED BY 850 MB TEMPERATURES. GFS IS
GENERALLY MUCH WARMER WHICH REFLECTS IN MODEL`S AFTERNOON HIGHS.
GIVEN HOW MUCH OF A WARM BIAS SEVERAL FORECAST DAYS HAVE BEEN
RECENTLY, WE`LL FOLLOW THE COOLER ECMWF IDEA, BUT USE GFS MOS
TEMPERATURES THAT ARE COOLER IN THE WEST.
A DRY PATTERN WILL BE ESTABLISHED THROUGH THE REMAINDER OF THE WEEK.
THE SYNOPTIC PATTERN INCLUDES A WEDGE OF RELATIVE SURFACE HIGH
PRESSURE ANCHORED FROM THE UPPER MIDWEST...SOUTHWEST ACROSS THE MID
MISSISSIPPI VALLEY INTO NORTHEAST TEXAS. WITH THE EXPECTED HURRICANE
OR TROPICAL STORM SPREADING WESTWARD INTO THE EASTERN TROUGH. THAT
PATTERN WILL MAINTAIN THE UPPER RIDGE FROM TUESDAY INTO THURSDAY
RIGHT OVER THE HIGH PLAINS REGIONS. LIGHT SOUTHERLY SURFACE WINDS
WILL BE THE PREVAILING WIND DIRECTION. HIGHS WILL INCREASE THROUGH
THE 60S, AND REACH THE LOW 70S WEDNESDAY OR THURSDAY. HIGHER
SURFACE DEW POINT INCREASING BACK INTO THE 30S WILL BRING OVERNIGHT
LOWS BACK ABOVE FREEZING THROUGH THE PERIOD AS WELL. BY FRIDAY, THE
UPPER FLOW BECOMES STRONGLY DIVERGENT ACROSS THE REGION AS A SHARP
TROUGH MOVES ACROSS THE WESTERN STATES, WHICH IS MODELED BY BOTH THE
GFS AND ECMWF. IN EITHER INSTANCE, THE WEATHER TYPE FOR THE REGION
APPEARS TO BE PRIMARILY WET - SHOWERS OR THUNDERSTORMS, BUT THE
MESOSCALE DETAILS ARE HIGHLY UNCERTAIN AT THIS TIME, AND COULD MISS
WESTERN KANSAS ALTOGETHER.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 620 PM CDT FRI OCT 26 2012
VFR CONDITIONS WILL PREVAIL ACROSS THE TAF SITES AS AN AREA OF
HIGH PRESSURE SHIFTS ACROSS NORTHERN KANSAS. THIS WILL ALLOW WINDS
TO BECOME LIGHT AND VARIABLE OVERNIGHT SHIFTING TO THE SOUTH AT 10
TO 15 KNOTS LATE TOMORROW MORNING.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 22 52 30 59 / 0 0 0 0
GCK 24 52 29 59 / 0 0 0 0
EHA 25 54 31 59 / 0 0 0 0
LBL 23 54 30 61 / 0 0 0 0
HYS 22 50 28 57 / 0 0 0 0
P28 23 52 29 59 / 0 0 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
HARD FREEZE WARNING FROM 10 PM THIS EVENING TO 9 AM CDT SATURDAY
FOR KSZ064>066-074>081-084>090.
&&
$$
SHORT TERM...GERARD
LONG TERM...RUSSELL
AVIATION...HOVORKA_42
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
732 PM EDT FRI OCT 26 2012
...Updated Aviation Discussion...
.Forecast Update...
Updated at 640 PM EDT Fri Oct 26 2012
Updated the forecast to adjust POPs and temps. Latest radar imagery
depicts the most widespread rains over northern KY and southeast
Indiana. This area of rain will continue to slowly move NE out of
our region this evening. However, another area of steady showers is
blossoming over northwest TN which is predicted (by RR and HRRR high
res models) to move northeast over central and east central KY
through around midnight. Thus, have tried to better time these
areas of steady rains throughout the evening hours in the forecast
grids.
Also did a slight tweak to hourly temps for this evening. They
should hold steady in areas already in mid 40s or fall into the 40s
in areas over east central KY that were around 50 or the lower 50s
as of 2230Z. New forecast products out shortly.
&&
.Short Term (Tonight through Saturday Night)...
Issued at 325 PM EDT Fri Oct 26 2012
The strong cold front has pushed through central Kentucky, with the
leading edge of post-frontal precip extending from near Frankfort to
Glasgow to just east of Nashville, TN as of 19Z. Temps will quickly
drop into the upper 40s as the rain spreads into the Bluegrass and
Lake Cumberland, and the ZFP may need a pre-1st period to account
for this.
Otherwise expect high POPs to continue into the evening hours as
this rain shield takes its sweet time moving east. Precip really
thins out over western Kentucky and western Tennessee, which points
to rain shutting off from SW to NE across the area during the night.
Will cut back POPs but with broad SW flow over the top of a shallow
cold air mass, not confident enough to dry things out completely
overnight. Temps will continue to drop in cold air advection, but
plenty of wind and cloud cover will keep lows from really bottoming
out. Look for upper 30s over parts of southern Indiana, but mainly
lower to mid 40s elsewhere.
Still hanging on to some morning precip in the Bluegrass on
Saturday, but this could be too generous. While there will be some
clearing it is still a chilly Canadian air mass. Low-confidence temp
forecast as it will depend heavily on how much clearing occurs.
Split the difference between MOS guidance with highs in the mid-50s,
except some lower 50s in the Bluegrass. Saturday night will be a few
degrees cooler, with most locations dipping into the 30s. Will not
be quite ideal for radiational cooling given a modest amount of
cloud cover and north winds staying up around 6 or 7 kts. Therefore
will not include any frost and the spread in temps will be rather
small.
.Long Term (Sunday through Friday)
Issued at 250 PM EDT Fri Oct 26 2012
What a change from just 24 hours ago! The long term forecast will
feature temperatures at least 10-15 degrees below normal each day.
Winds early on will be from the north and gusty, with how gusty
depending on how close Sandy gets to our forecast area. Winds will
shift slowly through the period to more westerly by midweek, where
it looks to remain the rest of the week. Tuesday looks to be the
most breezy, again based on hurricane center`s forecast proximity of
Sandy to our region. The remnants of Sandy look to continue to
influence our flow through the end of the work week.
The eastern forecast area will have the best chance for light precip
Sunday through Wednesday. Temperatures may be cool enough for a mix
Monday night and Tuesday night as well. Have thrown in a slight
chance for rain or snow for those periods. Do not expect
accumulations, as the ground still will be too warm for that.
Only other concern for the forecast would be any freezing Sunday
night through Wednesday night. Right now do not have any solid
freeze on any of the nights, just right around the freezing mark.
The wind should stay up enough each night to keep temperatures
fairly uniform and also to reduce the threat for frost.
&&
.Aviation (00Z TAF Issuance)...
Issued at 730 PM EDT Fri Oct 26 2012
Light on and off rain showers continue over the region behind a
cold front which passed through earlier today. Expect light showery
activity to continue at the TAF sites through at least the first
portion of the night at SDF/BWG and for most of the night at LEX.
Latest hi-res models suggests east central KY will be prone to on
and off periods of showery activity for most of the night. In
addition to showery activity, flight conditions will worsen
overnight into the IFR cat possibly even LIFR at LEX. 18Z NAM
soundings and MOS guidance indicate low cigs will settle in across
the region. Cigs/vsbys may bounce between IFR/MVFR through about
5Z, but cigs should become more established at IFR levels after 5Z.
With the best low level moisture expected at LEX, have included a
tempo for LIFR cigs/IFR vsbys between 5Z to 9Z. After 10Z though,
most of the rains will move out of the area with improving flight
conditions expected through the rest of the morning hours. Shortly
after sunrise, we should see cigs improve to MVFR levels with VFR
levels anticipated by early afternoon. With greater mixing and cigs
rising to around 3.5-4 kft by the afternoon hours, northerly winds
may gust to around 18-20 kts.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Update...........AMS
Short Term.......RAS
Long Term........RJS
Aviation.........AMS
AREA FORECAST DISCUSSION...UPDATED
NWS BALTIMORE MD/WASHINGTON DC
754 AM EDT THU OCT 25 2012
.SYNOPSIS...
HIGH PRESSURE WILL PERSIST ALONG THE NORTHEASTERN SEABOARD INTO THE
WEEKEND. A COLD FRONT WILL APPROACH THE MID ATLANTIC FROM THE WEST
FRIDAY NIGHT. THIS COLD FRONT WILL STALL THROUGH THE WEEKEND AS WHAT
IS CURRENTLY HURRICANE SANDY TRACKS NORTH OFF THE EASTERN SEABOARD.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPPER RIDGE POLEWARD OF HURRICANE SANDY WILL CONTINUE TO AMPLIFY
OVER THE ERN CONUS TDA. AT THE SFC...HIPRES OVER COASTAL NEW ENGLAND
WILL BUILD SWWD ALONG THE MID-ATLANTIC COAST. LLVL ELY SURGE
ASSOCIATED WITH THE SWD-BUILDING HIGH HAS ADVECTED MARINE AIR/LOW
CLOUDS INLAND OVNGT. OVC STRATUS DECK...WHICH HAS REACHED WEST OF
BALTIMORE AND ANNAPOLIS /AS CAPTURED BY THE 07Z 11-3.9U SAT
IMAGERY/ WILL EXPAND WWD TOWARD THE BLUE RIDGE THRU DAYBREAK.
GIVEN LOWER SUN ANGLE PRESENT IN LATE OCT...IT MAY TAKE THE ENTIRE
MRNG FOR STRATUS DECK TO ERODE...POSSIBLY LONGER INTO THE AFTN
TOWARD THE CHSPK BAY. WEST OF THE STRATUS...MSTLY SUNNY SKIES
WILL YIELD MAX TEMPS IN UPPER 70S TO NEAR 80F ACROSS CENTRAL VA
AND POTOMAC HIGHLANDS...WHILE TEMPS MAY STRUGGLE TO REACH 70F IN
NORTH-CENTRAL MD.
SFC HIPRES WILL CONTINUE TO RIDGE SWD TOWARD THE MID-ATLANTIC COAST
TNGT. WITH PERSISTENT ELY FLOW...MARINE LAYER WILL BE WEDGED IN EAST
OF THE MTS. SATURATED BOUNDARY LAYER AND SHALLOW ISENTROPIC LIFT
BENEATH SUBSIDENCE INVERSION SHOULD SUPPORT DEVELOPMENT OF
STRATUS...DRIZZLE AND FOG OVNGT EAST OF THE BLUE RIDGE AND IN THE
SHENANDOAH VLY.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY/...
COMBINATION OF SFC HIGH CENTERED OVER NEW ENGLAND COAST AND
HURRICANE SANDY MOVING NORTH FROM THE BAHAMAS WILL PRODUCE AN
ONSHORE FLOW FRIDAY AND SATURDAY.
FRIDAY...LOW CLOUDS AND DRIZZLE/LIGHT RAIN WILL PERSIST INTO THE
MORNING...THEN MIX OUT MIDDAY THROUGH THE AFTERNOON. LATE OCT
ONSHORE FLOW OF 5 TO 10 MPH WOULD PROBABLY NORMALLY RESULT IN LOW
CLOUDS/DRIZZLE ALL DAY. HOWEVER...IT LOOKS LIKE THE FETCH AROUND THE
HIGH IS PLENTY DRY DESPITE COMING OFF THE ATLANTIC...SO EROSION OF
THE CLOUDS SHOULD OCCUR. MAX TEMPS LOW 70S.
FRIDAY NIGHT AND SATURDAY...GOOD CONSENSUS ON COLD FRONT APPROACHING
THE CENTRAL APPALACHIANS AND SANDY EXPANDING IN SIZE. ONSHORE FLOW
INCREASES TO 10 TO 15 MPH. LITTLE IN THE WAY OF PRECIP...PERHAPS
SOME RAIN BLUE RIDGE AND WEST.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
MUCH UNCERTAINTY EXISTS IN THE INTERPLAY OF THE COLD FRONT/TROUGH
DIGGING THROUGH THE MIDWEST AND SANDY FOR THIS WEEKEND AND WELL
INTO NEXT WEEK. NHC FORECAST IS STILL FOR A POST-TROPICAL
TRANSITION AS IT MOVES INTO COOLER WATER NORTH OF HATTERAS.
WHETHER THE HYBRID SYSTEM THEN PHASES WITH THE UPR TROUGH AND
IMPACTS THE MID ATLANTIC /PER 00Z ECMWF/ OR IMPACTS NEW ENGLAND
/PER 00Z GFS/ OR SOMETHING IN BETWEEN REMAINS THE BIG QUESTION.
EITHER WAY COLD CANADIAN AIR WILL BE SPILLING IN WITH THE TROUGH TO
THE WEST AND THERE IS A CHANCE FOR SNOW /WITH POSSIBLE
ACCUMULATIONS/ OVER THE ALLEGHENY HIGHLANDS STARTING SUNDAY NIGHT.
THERE IS STILL A WIDE RANGE OF POSSIBLE IMPACTS TO THE LWX CWA
SUNDAY INTO THE MIDDLE PART OF NEXT WEEK. PLEASE SEE FUTURE
FORECASTS FOR FURTHER DETAILS.
&&
.AVIATION /08Z THURSDAY THROUGH MONDAY/...
AS OF 1145Z...EASTERLY LOW-LEVEL FLOW HAS PRODUCED A SHALLOW STRATUS
DECK WITH IFR CIGS. THIS DECK HAS MADE ITS WAY WESTWARD...COVERING
ALL OF THE TERMINALS EAST OF THE BLUE RIDGE. AND MRB IS EXPECTED TO
GO DOWN SHORTLY...BY 1230Z...BUT CHO SHOULD REMAIN VFR. THE BEST
MODEL THAT IS HANDLING THE LOW CIGS THIS MORNING IS THE 3KM HRRR.
QUICK PEEK AT THE LATEST 09Z HRRR SHOWS LOW CIGS LOCKED IN THROUGH
AT LEAST 18Z...ALTHO THERE SHOULD BE SOME LIFTING IN CIG BASE AS THE
MORNING PROGRESSES. BUT SHALLOW NATURE VS WEAK OCT SUN SUGGESTS THE
HRRR MIGHT BE RIGHT. FOR NOW...WILL KEEP SOME IMPROVEMENT FOR VFR IN
TAFS AFTER 17Z AT IAD/DCA...AND 18Z AT BWI/MTN. MVFR VSBYS WILL
PERSIST THIS MORNING AS WELL ASSOCIATED WITH THE STRATUS.
PREVIOUS DISCUSSION CONTINUES...
WITH ELY FLOW PERSISTING INTO TNGT...STRATUS SHOULD REDEVELOP DURING
THE LATE EVE/OVNGT. CONFIDENCE FOR IFR CIGS AND DZ AT ALL TERMINALS
RELATIVELY HIGH FOR 24 HOURS OUT.
ONSHORE FLOW 5 TO 10 KT AND IFR CIGS ERODE FRIDAY MIDDAY AND
AFTERNOON. FLOW INCREASES FRIDAY NIGHT AND SATURDAY WITH GUSTS
PERHAPS TO 15 KT. MUCH UNCERTAINTY THIS WEEKEND INTO NEXT WEEK WITH
THE TRACK OF WHAT IS CURRENTLY HURRICANE SANDY.
&&
.MARINE...
ELY FLOW 5-10 KT TDA AND TNGT. EXPECT AREAS OF DZ TO DEVELOP LATE
THIS EVE AND OVNGT.
EASTERLY FLOW WILL PERSIST THROUGH FRIDAY BEFORE TURNING
NORTHEASTERLY. SCA MAY BE WARRANTED SATURDAY NIGHT AS FLOW
INCREASES. SANDY WILL BE MOVING NORTHWARD EAST OF THE COASTLINE
SUNDAY AND MONDAY. THERE ARE MANY UNCERTAINTIES WITH THE TRACK BUT
GALE WRNGS MAY BE WARRANTED SUNDAY NIGHT AND MONDAY.
&&
.TIDES/COASTAL FLOODING...
WATER LEVELS WILL CONTINUE TO SLOWLY TO RISE AS EASTERLY FLOW SLOWLY
INCREASES THROUGH SATURDAY. WAXING MOON WILL BE FULL SUNDAY...
MAXIMIZING THE IMPACTS. MINOR THRESHOLDS MAY BE REACHED BY FRIDAY
AFTERNOON. POTENTIAL FOR MORE SIGNIFICANT IMPACTS SUNDAY AND MONDAY
AS WHAT IS NOW HURRICANE SANDY IS FCST TO BECOME POST TROPICAL
WHILE TRACKING NORTH. PLEASE MONITOR NATIONAL HURRICANE CENTER
PRODUCTS AND OUR HAZARDOUS WEATHER OUTLOOK FOR UPDATES ON THIS
SITUATION.
&&
.CLIMATE...
THE HIGH TEMPERATURE OF 84F YDA...24 OCT...AT DCA TIED THE DAILY
RECORD HIGH SET IN 2001. IT WAS ALSO THE LATEST DAY IN THE
CALENDAR YEAR TO REACH 84F SINCE 24 OCT 2001.
&&
.EQUIPMENT...
STARTING 18Z TDA...UPPER AIR OBSERVATIONS WILL BE CONDUCTED EVERY
6-H AT ALL NWS CONUS RAOB SITES...INCLUDING HERE AT WFO LWX...TO
SUPPORT FCST OPERATIONS FOR SANDY.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.
&&
$$
UPDATE...SMZ FOR AVIATION
PREV DISC...KLEIN/BAJ
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
139 AM EDT THU OCT 25 2012
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 416 PM EDT WED OCT 24 2012
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW SW FLOW ALF OVER
THE PLAINS BTWN DEEP TROF OFF THE PACIFIC COAST AND AN UPR RDG AXIS
ALIGNED FM HUDSON BAY THRU THE CENTRAL GRT LKS INTO THE SE CONUS.
DESPITE THE PRESENCE OF AN UNSEASONABLY WARM...MOIST LLVL AIRMASS
/PWATS UP TO 250 PCT OF NORMAL/ OVER THE UPR GRT LKS...THERE ARE
ONLY A FEW -SHRA NOTED ON THE MQT RADAR DUE TO STRONG CAPPING INVRN
BTWN H75-8 AS NOTED ON THE LOCAL 12Z RAOBS EVEN THOUGH A SHALLOW...
WEAK COLD FNT ATTENDANT TO CLOSED LO OVER SASKATCHEWAN HAS LIMPED
INTO THE FAR WRN CWA. A DISTURBANCE WITH 70KT H5 WINDS LIFTING NEWD
THRU THE DAKOTAS IS CAUSING AN AREA OF -SHRA UNDER SHARP H7 TEMP
GRADIENT OVER THE NRN PLAINS INTO NW MN WELL WELL W OF THE SFC COLD
FNT AND THE AREA INFLUENCED BY THE SHARP MID LVL CAP. THE SHRTWV IN
THE NRN PLAINS AND ANOTHER MORE VIGOROUS DISTURBANCE MOVING THRU THE
CNTRL ROCKIES HAVE CONSPIRED TO CAUSE A LO PRES TO DVLP FARTHER S ON
THE COLD FNT IN KANSAS. OVER UPR MI... AREAS OF FOG LINGER
ESPECIALLY OVER THE CENTRAL ZNS WHERE LLVL SSE FLOW IS UPSLOPING.
THE LOWERING SUN ANGLE AND PERSISTENT FOG AND LO CLDS HAVE LIMITED
SFC WARMING. FARTHER TO THE S...MORE BREAKS IN THE LO CLDS HAVE
ALLOWED FOR MORE SFC WARMING OVER ERN IOWA AND SRN WI.
TNGT...MAIN FCST CONCERNS ARE SHRA/TS CHCS AND POTENTIAL FOR SVR WX
AS DISTURBANCES LIFT TO THE NE OUT OF MEAN WRN TROF. SPC HAS PLACED
WRN UPR MI IN A SLGT RISK FOR SVR STORMS TNGT. GIVEN ABSENCE OF ANY
SGNFT SFC WARMING OVER UPR MI THIS AFTN AND SHARP INVRN...ANY
CONVECTION SHUD BE ELEVATED AND DEPENDENT ON WHETHER/HOW QUICKLY THE
SHARP H8-75 INVRN WEAKENS. 12Z GFS/NAM HAVE TRENDED TO SHIFT FOCUS
FOR MOST SGNFT DEEP LYR QVECTOR CNVGC ASSOCIATED WITH DISTURBANCE
NOW IN THE NRN PLAINS INTO MN AT 00Z...A LOGICAL SHIFT GIVEN HI
AMPLITUDE PATTERN IN PLACE AND SHIFT OF SECOND SHRTWV FARTHER W INTO
THE UPR TROF AXIS. HIER RES NAM RUN SHOWS THE SHARPEST/SLOPED H85-7
FGEN/UVV IMPACTING WRN LK SUP AT 00Z BEFORE SHIFTING TO THE NE AS
THE DEEP LYR QVECTOR CNVGC ASSOCIATED WITH THE FIRST SHRTWV FADES AS
THE UPR TROF DEEPENS FARTHER W WITH CLOSER APRCH OF 2ND SHRTWV.
GIVEN THE STRENTH OF THE CAPPING ILLUSTRATED BY THE 12Z RAOBS...
SUSPECT MOST WDSPRD AND INTENSE SHRA/TS THIS EVNG WL MISS THE LAND
CWA TO THE W...WITH ALL BUT THE FAR W SEEING NOTHING MORE THAN
ISOLD-SCT -SHRA/TS OR -DZ IN THIS SCENARIO AS WEAKER FORCING HERE
LIMITS THE WEAKENING OF THE CAP. EVEN THE NAM DOES SHOW A SECOND
AREA OF HIER QPF OVER THE SE ZNS...AND THIS MIGHT DEPEND ON IF SOME
SHRA DVLP WITH THE CLRG OVER SE WI AND MOVE TO THE N. ALTHOUGH THE
GFS SHOWS SIMILAR UPR FORCING...THIS MODEL...WITH THE SUPPORT OF THE
12Z CNDN GEM MODEL...SHOWS AXIS OF HIER QPF OVER WRN UPR MI NEAR THE
SFC COLD FNT. GIVEN THE PLACEMENT OF THE SHARPER DYNAMICS AND
PATTERN RECOGNITION... THINK THE NAM FCST IS THE BEST BET. GIVEN
IMPRESSIVE DEEP LYR SHEAR ABV THE MORE STABLE LYR NEAR THE SFC...ANY
TS THAT MIGHT IMPACT THE WRN ZNS COULD TURN SVR WITH HAIL THE MAIN
THREAT GIVEN SFC BASED STABILITY. WITH THE UNSEASONABLY WARM...MOIST
AIRMASS IN PLACE AND HI FRZG LVL...ANY SHRA COULD DUMP HEAVY RA EVEN
IF THEY ARE FAST MOVING UNDER THE STEADY FLOW ALF. AS THE SECOND
SHRTWV RIDES NEWD LATER TNGT...ANOTHER AREA OF VIGOROUS H85-5
QVECTOR CNVGC/UPR DVGC IS PROGGED TO IMPACT MAINLY MN TOWARD 12Z. SO
AFT INITIAL ROUND OF HIER POPS LIFTS TO THE NE...SUSPECT ANOTHER
ROUND OF HEAVIER SHRA/SOME TS WL INVADE THE WRN CWA LATER. WITH ONLY
MODEST DIURNAL COOLING...EXPECT FOG TO REDVLP... ESPECIALLY IN AREAS
OVER THE ECNTRL EXPERIENCING UPSLOPE SSE WINDS.
THU...AS DISTURBANCE/ACCOMPANYING H3 JET MAX AND DEEP LYR QVECTOR
CNVGC/UPR DVGC RIDE TO THE NNE WITH ASSOCIATED SFC LO MOVING UP THE
STALLED COLD FNT OVER THE W...EXPECT AN AREA OF SHRA/EMBEDDED TS TO
IMPACT MAINLY THE W HALF IN THE MRNG BEFORE THE SHRTWV MOVES FAR
ENUF TO THE N AND DEEP LYR QVECTOR DVGC DVLPS WITH DNVA/STRONG CAD
IN THE WAKE OF COLD FROPA AS SFC LO MOVES INTO ONTARIO IN THE AFTN.
THINK CATEGORICAL POPS ARE APPROPRIATE OVER THE W IN THE MRNG...WITH
THE HIER POPS FOLLOWING THE COLD FROPA TO THE E. ALTHOUGH SFC BASED
STABILITY WL LIMIT THE INCRS IN WIND SPEED BLO ADVY LVL...S WINDS
NEAR LK MI MAY BECOME QUITE GUSTY IN ADVANCE OF THE COLD FROPA UNDER
H925 WINDS UP TO 50 KTS AND WITH SHARP PRES FALL CENTER MOVING INTO
ONTARIO AHEAD OF THE SFC LO PROVIDING ENHANCEMENT TO THE S GRADIENT
FLOW. COMBINATION OF STRONG CAD AND W H925 WINDS INCRSG UP TO 35-40
KT IN THE WAKE OF THE FROPA MIGHT CAUSE WIND GUSTS OVER THE EXPOSED
KEWEENAW TO AT LEAST APRCH ADVY LVL IN THE AFTN. ENUF COLD AIR MAY
ARRIVE TO AT LEAST MIX LINGERING USPLOPE LK ENHANCED -SHRA WITH SN
OVER THE FAR W IF THE COLDER NAM SHOWING H85 TEMPS FALLING TOWARD
-5C AT 00Z FRI VERIFIES. THE SHARP COLD FROPA WARRANTS A NON DIURNAL
TEMP TREND...WITH TEMPS FALLING BEHIND THE FROPA ESPECIALLY OVER THE
W.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 416 PM EDT WED OCT 24 2012
BY EARLY THURSDAY EVENING...THE MAIN SFC LOW SHOULD BE OVER NE
ONTARIO...WITH THE COLD FRONT JUST E OF UPPER MI...AND A SECONDARY
TROUGH SET UP E-W FROM THE LOW ACROSS LAKE WINNIPEG. THE 500MB LOW
OVER LAKE WINNIPEG WILL SLIDE NNE OUT OF THE AREA.
W FLOW AND 850MB TEMPS AROUND -8C SHOULD HELP KEEP SOME LAKE
ENHANCED SHOWER ACTIVITY GOING ACROSS W UPPER MI. HOWEVER...THE LOW
LEVEL MOISTURE WILL BE QUITE A BIT LESS DURING THAT TIME...WITH
PLENTY OF CLOUDS BUT JUST LIGHT SNOW SHOWERS OR FLURRIES POSSIBLE.
EXPECT THE SECONDARY TROUGH TO PUSH ACROSS THE KEWEENAW PENINSULA
FRIDAY EVENING...BUT HAVE LITTLE WITH IT AS MUCH OF THE ENERGY
REMAINS CLOSER TO THE SFC LOW ITSELT OVER N HUDSON BAY BY THAT TIME.
ANOTHER ROUND OF CLOUDS AND LIGHT SNOW SHOWERS. NO SIGNIFICANT
ACCUMULATION IS EXPECTED...AS THE BEST SNOW GROWTH REGION /AOA
800MB/ REMAINS WELL ABOVE THE MOISTURE.
THE LARGE SCALE TROUGH WILL DOMINATE MUCH OF THE NATION FRIDAY NIGHT
THROUGH AT LEAST SATURDAY. AN ELONGATED AREA OF HIGH PRESSURE
STRETCHING FROM THE MAIN HIGH OVER CENTRAL CANADA TO THE CENTRAL
PLAINS FRIDAY NIGHT WILL SLOWLY BUILD ACROSS THE UPPER GREAT
LAKES...THROUGH AT LEAST SUNDAY.
HIGH PRESSURE WILL REMAIN STRONG OVER ONTARIO THROUGH THE MID MS
VALLEY...EVEN AS THE STRONG SYSTEM PUSHES TOWARDS THE EAST COAST. AS
A RESULT OF THE NEARING STORM SYSTEM...THE SFC HIGH SHOULD MAINTAIN
ITS INFLUENCE OVER THE W HALF OF UPPER MI. HOWEVER...N FLOW WILL
LIKELY DOMINATE FAR E UPPER MI FROM SUNDAY NIGHT THROUGH THE END OF
THE FCST PERIOD /WEDNESDAY/ AS THE LOW RETROGRADES .
UNLIKE THE ECMWF WHICH CONTINUES TO SHOW GOOD RUN TO RUN CONSISTANCY
ON THE POTENTIAL STORM SYSTEM SLIDING TOWARDS THE E COAST...THE GFS
IS A BIT MORE JUMPY. THE MODEL IS SPLIT ON WHETHER TO BRING THE LOW
OFF TO SEE...OR EVEM MORE ONSHORE BY WEDNESDAY MORNING /NEAR LAKE
HURON/ IF THE 24/06Z RUN IS CORRECT. THE 24/12Z GFS SHIFTED THE
500MB LOW APPROX 300-350MI W OF ITS PREVIOUS MORE OUT TO SEA
LOCATION MONDAY MORNING. WILL CONTINUE TO HEDGE THE FCST A BIT
CLOSER TO THE MORE STABLE ECMWF SOLUTION.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 138 AM EDT THU OCT 25 2012
QUITE A PESSIMISTIC FORECAST IN THE MAKING AS ABUNDANT MOISTURE AND
AN OVERALL STAGNANT AIRMASS ALONG A SURFACE BOUNDARY WILL KEEP CIGS
AND VIS QUITE LOW AT ALL SITES THROUGH MUCH OF THE TAF PERIOD.
GIVEN GENERAL FLOW FROM THE N...HAVE KEPT CIGS IN THE VLIFR/LIFR
RANGE OVERNIGHT. DO NOT EXPECT MUCH IMPROVEMENT AT IWD WITH FLOW OUT
OF THE NORTH TO NE THROUGH EARLY THURSDAY MORNING. DRIER AIR WILL
MOVE IN BY LATE AFTERNOON AND EVENING WHICH SHOULD BRING IMPROVING
CONDITIONS INTO THE MVFR RANGE.
A PERIOD OF MVFR CIGS VSBY FOLLOWING AN ARES OF SHRA/TSRA MAY LOWER
AGAIN INTO THE IFR RANGE WITH ABUNDANT LOW LEVEL MOISTURE REMAINING
OVER THE AREA. A STRONG COLD FRONT SHOULD REACH CMX BY 18Z
THURSDAY...WITH A QUICK WIND SHIFT TO THE WNW AND WIND SPEED
INCREASE TO AROUND 20KT.
SSE UPSLOPE FLOW AT SAW HAD REMAINED BELOW LANDING MINS MOST OF THIS
EVENING BUT HAVE LIFTED SLIGHTLY AFTER SOME LIGHT RAIN MOVED
THROUGH. EXPECT THAT THE FOG AND LOW CIGS WILL CONTINUE UNTIL MORE
PERSISTENT RAIN MOVES IN LATE TONIGHT AND THU WHEN WINDS SHIFT MORE
TO THE SSW AND REDUCE UPSLOPE FLOW AHEAD OF THE APPROACHING COLD
FRONT. LASTLY...MARGINAL LLWS OF ABOUT 30-40KTS OVER THE LOWEST
1.5KFT IS POSSIBLE AS WINDS ALOFT INCREASE AHEAD OF THE FRONT.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 416 PM EDT WED OCT 24 2012
EXPECT DENSE FOG OVER THE W HALF OF LAKE SUPERIOR TO LINGER THRU
THIS EVENING BEFORE THE ARRIVAL OF SOMEWHAT DRIER LOW LEVEL AIR IS
ABLE TO DISSIPATE THE FOG. THE DENSER FOG WILL LINGER LONGEST NEAR
THE W SHORE OF UPPER MI. OTHERWISE...EXPECT S WINDS TO INCREASE TO
30 KTS OVER THE E HALF OF THE LAKE ON THU AS A STRONG COLD FRONT
APPROACHES. RELATIVELY LIGHT WINDS OVER THE W AND CENTRAL WILL SHIFT
TO THE W FOLLOWING THE COLD FROPA ON THU AND INCREASE UP TO 30 KTS
IN THE AFTERNOON...WITH HIGH PRESSURE DEVELOPING OVER THE NORTHERN
AND CENTRAL PLAINS. THERE MAY BE SOME GALE FORCE WINDS NEAR THE KEWEENAW
LATE IN THE DAY. THESE MARGINAL GALES WILL LIKELY IMPACT PORTIONS OF
THE CENTRAL LAKE ON THU EVENING...SO HOISTED A GALE WATCH FOR NOW IN
THIS AREA. LIGHTER WINDS WITH HIGH PRESSURE WILL SLOWLY PUSH OVER
THE UPPER GREAT LAKES THROUGH MONDAY...WITH THE STRONGEST WINDS OVER
E LAKE SUPERIOR.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WATCH FROM THIS EVENING THROUGH LATE TONIGHT FOR LSZ265-266.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...KF
AVIATION...JLB
MARINE...KC/KF
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1215 PM CDT THU OCT 25 2012
.UPDATED FOR 18Z AVIATION DISCUSSION...
.DISCUSSION...
PRIMARY FORECAST CONCERNS THIS MORNING ARE PRECIP TYPE AND AMOUNTS
ASSOCIATED WITH A SHORTWAVE TROUGH EJECTING OUT OF THE ROCKIES. AT
THE LOWER LEVELS...MOISTURE TRANSPORT OVERRUNNING THE SURFACE
BOUNDARY CONTINUES TO SPAWN CONVECTION FROM SOUTHERN MINNESOTA
INTO WEST CENTRAL WI. EMBEDDED THUNDER WILL CONTINUE TO BE
POSSIBLE ACROSS THE EASTERN HALF OF THE FORECAST AREA THIS MORNING
WHERE ELEVATED INSTABILITY EXISTS. MEANWHILE...THE ATTENDANT
DEFORMATION SNOW BAND HAS ENTERED WEST CENTRAL MN...AND WILL
GRADUALLY EXPAND EASTWARD ACROSS THE AREA OVER THE NEXT 12 HOURS
AS THE TROUGH SHIFTS EAST. HAVE SPED UP THE TRANSITION OF RAIN TO
SNOW...PER CURRENT TRENDS AND NAM/GFS/RAP/SREF/ARW BUFKIT
PROFILES...WHICH INDICATE SNOW MIXING IN WITH THE RAIN OVER THE
REMAINDER OF CENTRAL MN BETWEEN 15Z AND 18Z...AND IN WEST CENTRAL
WI BETWEEN 18Z AND 21Z. THE HRRR AND HI-RESW-NMMEAST SIMULATED
PRECIP TYPE PROGS COMPLEMENT THIS THINKING AS WELL. SNOWFALL
AMOUNTS STILL APPEAR TO TOP OUT FROM 1 TO 2 INCHES OVER WEST
CENTRAL MN...WITH NOT MORE THAN A TRACE EXPECTED TO THE EAST DUE
TO THE EXPECTATION THAT PRECIP WILL BE SHUTTING OFF AROUND OR
SHORTLY AFTER SNOW DEVELOPS. SURFACE TEMPERATURES WILL REMAIN
STEADY OR GRADUALLY FALL THIS AFTERNOON AS STRONG COLD ADVECTION
ENSUES IN THE WAKE OF THE TROUGH. ACCOMPANYING NORTHWEST WINDS OF
15 TO 25 MPH WILL CREATE QUITE BRISK CONDITIONS THIS
AFTERNOON...AS WIND CHILLS DECREASE INTO THE 20S.
PRECIPITATION SHOULD COME TO AN END BY THIS EVENING...WITH MOSTLY
CLEAR SKIES EXPECTED FOR TONIGHT. TEMPERATURES WILL FALL INTO THE
25 TO 30 DEGREE RANGE FOR THE MOST PART. CONTINUED COLD
TEMPERATURES WILL PERSIST FOR FRIDAY...WITH HIGHS ONLY REACHING
THE UPPER 30S AND LOWER 40S.
BROAD SURFACE HIGH PRESSURE AND MID LEVEL TROUGHING WILL TRANSLATE
TO CONTINUED BELOW NORMAL TEMPERATURES THROUGH THE WEEKEND. HIGHS
WILL MAINLY RANGE FROM AROUND 40 TO 45 DEGREES ON SATURDAY AND
SUNDAY...WITH SUB-FREEZING LOWS. FRIDAY NIGHT APPEARS TO BE THE
COLDEST NIGHT OF THE WEEKEND...WHEN READINGS ARE EXPECTED TO DIP TO
BETWEEN 20 AND 25 DEGREES. MORE CLOUD COVER AND EVEN LIGHT SNOW
WILL BE POSSIBLE FOR SATURDAY NIGHT ACROSS WEST CENTRAL AND SOUTH
CENTRAL MN...AS A WEAK MID LEVEL WAVE CLIPS THE SOUTHERN HALF OF
THE STATE.
TEMPERATURES WILL SLOWLY MODERATE AT THE START OF THE UPCOMING
WEEK...WITH HIGHS IN THE MID 40S TO LOWER 50S BY WEDNESDAY.
&&
.AVIATION.../18Z TAF ISSUANCE/
COUPLE OF SNOW BANDS MOVING ACROSS MN PORTION OF THE AREA...WITH
LIGHT RAIN AFFECTING WESTERN WISCONSIN. INITIAL SNOW BAND OVER EAST
CENTRAL MN WILL MOVE EAST INTO WISCONSIN FOR THE AFTERNOON. WILL
SEE RAIN/SNOW MIX POSSIBLE CHANGING OVER TO ALL SNOW LATE AFTERNOON
BEFORE ENDING AT KEAU. SECOND PERSISTENT SNOW BAND MATCHES WELL
WITH HE MINUS 15C OMEGA FIELD AND THIS WILL LIFT NORTHEAST AND
WEAKEN THROUGH 20Z. SNOW WILL HAVE ENDED OVER THE FAR WESTERN AREA
AND SOON AT KSTC...WHERE SOME SLUSHY ACCUMULATION ON GRASSY AREAS
LIKELY OCCURRED. LESS THAN AN INCH THOUGH. CEILING IMPROVING A BIT
DIRECTLY BEHIND TROUGH...BUT SOME CONCERN OF MVFR CEILINGS
DEVELOPING BEHIND TROUGH LATER TONIGHT. SUBSIDENCE WILL BE STRONG
INITIALLY OR DIRECTLY BEHIND TROUGH...SO WILL CONTINUE TREND OF
REMAINING SCT OVERNIGHT. NORTHWEST WINDS WILL DIMINISH THIS EVENING
AND COULD BECOME GUSTY AGAIN OVER EASTERN AREAS AT LEAST INTO EARLY
AFTERNOON...BEFORE RIDGE BUILD IN ENOUGH. MAY SEE SOME BKN VFR
CEILINGS AGAIN...ESPECIALLY EAST IN THE LATE MORNING/AFTERNOON WITH
RESIDUAL MOISTURE AND SOME NEGATIVE CU RULES INDICATED.
KMSP...
IFR CONDITIONS FOR A FEW HOURS YET AS A COUPLE OF SNOW BANDS MOVE
THROUGH. MAY MIX WITH RAIN BETWEEN STRONGER VERTICAL MOTION.
SHOULD END BY 22Z WITH VFR CONDITIONS THEREAFTER. SOME CONCERN OF
LOWER CEILINGS MOVING IN AGAIN LATER TONIGHT FROM THE WEST...BUT
WILL REMAIN SCT FOR NOW. STRONG NORTHWEST WINDS WILL DIMINISH THIS
EVENING AND MAY BECOME GUSTY AGAIN INTO FRI AFTERNOON.
/OUTLOOK FOR KMSP/
FRI AFTN...VFR. WINDS WNW 10 G 20KTS.
SAT...VFR. WINDS LGT AND VRB.
SUN...MVFR/VFR. CHC -RASN. WINDS SE AT 5 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
LS/DE
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
622 AM CDT THU OCT 25 2012
.DISCUSSION...
PRIMARY FORECAST CONCERNS THIS MORNING ARE PRECIP TYPE AND AMOUNTS
ASSOCIATED WITH A SHORTWAVE TROUGH EJECTING OUT OF THE ROCKIES. AT
THE LOWER LEVELS...MOISTURE TRANSPORT OVERRUNNING THE SURFACE
BOUNDARY CONTINUES TO SPAWN CONVECTION FROM SOUTHERN MINNESOTA
INTO WEST CENTRAL WI. EMBEDDED THUNDER WILL CONTINUE TO BE
POSSIBLE ACROSS THE EASTERN HALF OF THE FORECAST AREA THIS MORNING
WHERE ELEVATED INSTABILITY EXISTS. MEANWHILE...THE ATTENDANT
DEFORMATION SNOW BAND HAS ENTERED WEST CENTRAL MN...AND WILL
GRADUALLY EXPAND EASTWARD ACROSS THE AREA OVER THE NEXT 12 HOURS
AS THE TROUGH SHIFTS EAST. HAVE SPED UP THE TRANSITION OF RAIN TO
SNOW...PER CURRENT TRENDS AND NAM/GFS/RAP/SREF/ARW BUFKIT
PROFILES...WHICH INDICATE SNOW MIXING IN WITH THE RAIN OVER THE
REMAINDER OF CENTRAL MN BETWEEN 15Z AND 18Z...AND IN WEST CENTRAL
WI BETWEEN 18Z AND 21Z. THE HRRR AND HI-RESW-NMMEAST SIMULATED
PRECIP TYPE PROGS COMPLEMENT THIS THINKING AS WELL. SNOWFALL
AMOUNTS STILL APPEAR TO TOP OUT FROM 1 TO 2 INCHES OVER WEST
CENTRAL MN...WITH NOT MORE THAN A TRACE EXPECTED TO THE EAST DUE
TO THE EXPECTATION THAT PRECIP WILL BE SHUTTING OFF AROUND OR
SHORTLY AFTER SNOW DEVELOPS. SURFACE TEMPERATURES WILL REMAIN
STEADY OR GRADUALLY FALL THIS AFTERNOON AS STRONG COLD ADVECTION
ENSUES IN THE WAKE OF THE TROUGH. ACCOMPANYING NORTHWEST WINDS OF
15 TO 25 MPH WILL CREATE QUITE BRISK CONDITIONS THIS
AFTERNOON...AS WIND CHILLS DECREASE INTO THE 20S.
PRECIPITATION SHOULD COME TO AN END BY THIS EVENING...WITH MOSTLY
CLEAR SKIES EXPECTED FOR TONIGHT. TEMPERATURES WILL FALL INTO THE
25 TO 30 DEGREE RANGE FOR THE MOST PART. CONTINUED COLD
TEMPERATURES WILL PERSIST FOR FRIDAY...WITH HIGHS ONLY REACHING
THE UPPER 30S AND LOWER 40S.
BROAD SURFACE HIGH PRESSURE AND MID LEVEL TROUGHING WILL TRANSLATE
TO CONTINUED BELOW NORMAL TEMPERATURES THROUGH THE WEEKEND. HIGHS
WILL MAINLY RANGE FROM AROUND 40 TO 45 DEGREES ON SATURDAY AND
SUNDAY...WITH SUB-FREEZING LOWS. FRIDAY NIGHT APPEARS TO BE THE
COLDEST NIGHT OF THE WEEKEND...WHEN READINGS ARE EXPECTED TO DIP TO
BETWEEN 20 AND 25 DEGREES. MORE CLOUD COVER AND EVEN LIGHT SNOW
WILL BE POSSIBLE FOR SATURDAY NIGHT ACROSS WEST CENTRAL AND SOUTH
CENTRAL MN...AS A WEAK MID LEVEL WAVE CLIPS THE SOUTHERN HALF OF
THE STATE.
TEMPERATURES WILL SLOWLY MODERATE AT THE START OF THE UPCOMING
WEEK...WITH HIGHS IN THE MID 40S TO LOWER 50S BY WEDNESDAY.
&&
.AVIATION.../12Z TAF ISSUANCE/
THE MAIN AVIATION CONCERNS ARE WHEN THE TRANSITION OF -RA TO -SN
OCCURS ACROSS EASTERN MN OVER THE NEXT FEW HRS...AND HOW LONG IT
WILL STAY -SN...OR HAVE A MIXTURE OF RAIN/SNOW BY 18Z.
A LARGE CONVECTIVE BAND OF SHRA/TSRA HAS MOVED OFF TO THE EAST OF
THE FA...WITH ONLY EAU HAVING A SMALL CHC OF CONTINUING VCTS
BETWEEN 12-13Z. THE ZONE WHERE -RA CHG OVER TO SNOW IS NEAR RWF TO
STC...AND THE LOCAL DUAL-POL CC INDICATED THAT THE FREEZING LEVEL
HAS FALLEN OVER THE PAST HR OR TWO.
STARTED OUT WITH ONLY SNOW AT STC/RWF...WITH RNH/MSP CHG OVER
BETWEEN 15-16Z...AND EAU ARND 18-20Z. MODEL SOUNDINGS INDICATED
THAT WHEN THE ATMOSPHERIC COLUMN SATURATED BELOW ZERO...IT REMAINS
BELOW ZERO THRU THE AFTN AT AXN/RWF/RHN/MSP. THIS WOULD MEAN THAT
ONCE THE LT SNOW BEGAN IT WOULD CONTINUE AND NOT CHG OVER.
HOWEVER...SFC TEMPS WILL RANGE FROM 34 TO 38 DEGREES BY
18Z...MAKING FOR A MIXTURE MORE LIKELY. THEREFORE...CONTINUED
WITH A MIXTURE OF BOTH -SN/-RA AT RHN/MSP WHERE THE PRECIPITATION
WILL LINGER INTO THE EARLY AFTN. RWF/STC WILL LIKELY SEE THE
PRECIPITATION END BEFORE THE SWITCH OVER BACK TO -SN/-RA DEVELOPS.
WINDS WILL BE FROM THE NNW/NW DURING THE DAY...WITH GUSTS OVER
22-26 KTS. EXPECT SOME DECREASE IN THE OVERALL SPEED DURING THE
EVENING...ALONG WITH THE GUSTY WINDS ENDING.
KMSP...
HIGH END IFR/LOW END MVFR CIGS WILL CONTINUE THRU 18Z...WITH A
PERIOD OF MAINLY -RA THRU 15Z...THEN CHG OVER TO -SN...OR A
MIXTURE OF -SN/-RA BETWEEN 15-16Z. MOST OF THE PRECIPITATION
SHOULD TAPER OFF AFT 18Z...WITH CIGS RISING TO VFR AFT 21Z. GUSTY
WINDS WILL CONTINUE DURING THE DAYTIME HRS...WITH A FEW GUSTS OVER
24 KTS. WINDS WILL REMAIN FROM THE WNW OVERNIGHT.
/OUTLOOK FOR KMSP/
FRI AFTN...VFR. WINDS WNW 10 G 20KTS.
SAT...VFR. WINDS LGT AND VRB.
SUN...MVFR/VFR. CHC -RASN. WINDS SE AT 5 KTS.
..JLT..
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
LS/JLT
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
348 AM CDT THU OCT 25 2012
.DISCUSSION...
PRIMARY FORECAST CONCERNS THIS MORNING ARE PRECIP TYPE AND AMOUNTS
ASSOCIATED WITH A SHORTWAVE TROUGH EJECTING OUT OF THE ROCKIES. AT
THE LOWER LEVELS...MOISTURE TRANSPORT OVERRUNNING THE SURFACE
BOUNDARY CONTINUES TO SPAWN CONVECTION FROM SOUTHERN MINNESOTA
INTO WEST CENTRAL WI. EMBEDDED THUNDER WILL CONTINUE TO BE
POSSIBLE ACROSS THE EASTERN HALF OF THE FORECAST AREA THIS MORNING
WHERE ELEVATED INSTABILITY EXISTS. MEANWHILE...THE ATTENDANT
DEFORMATION SNOW BAND HAS ENTERED WEST CENTRAL MN...AND WILL
GRADUALLY EXPAND EASTWARD ACROSS THE AREA OVER THE NEXT 12 HOURS
AS THE TROUGH SHIFTS EAST. HAVE SPED UP THE TRANSITION OF RAIN TO
SNOW...PER CURRENT TRENDS AND NAM/GFS/RAP/SREF/ARW BUFKIT
PROFILES...WHICH INDICATE SNOW MIXING IN WITH THE RAIN OVER THE
REMAINDER OF CENTRAL MN BETWEEN 15Z AND 18Z...AND IN WEST CENTRAL
WI BETWEEN 18Z AND 21Z. THE HRRR AND HI-RESW-NMMEAST SIMULATED
PRECIP TYPE PROGS COMPLEMENT THIS THINKING AS WELL. SNOWFALL
AMOUNTS STILL APPEAR TO TOP OUT FROM 1 TO 2 INCHES OVER WEST
CENTRAL MN...WITH NOT MORE THAN A TRACE EXPECTED TO THE EAST DUE
TO THE EXPECTATION THAT PRECIP WILL BE SHUTTING OFF AROUND OR
SHORTLY AFTER SNOW DEVELOPS. SURFACE TEMPERATURES WILL REMAIN
STEADY OR GRADUALLY FALL THIS AFTERNOON AS STRONG COLD ADVECTION
ENSUES IN THE WAKE OF THE TROUGH. ACCOMPANYING NORTHWEST WINDS OF
15 TO 25 MPH WILL CREATE QUITE BRISK CONDITIONS THIS
AFTERNOON...AS WIND CHILLS DECREASE INTO THE 20S.
PRECIPITATION SHOULD COME TO AN END BY THIS EVENING...WITH MOSTLY
CLEAR SKIES EXPECTED FOR TONIGHT. TEMPERATURES WILL FALL INTO THE
25 TO 30 DEGREE RANGE FOR THE MOST PART. CONTINUED COLD
TEMPERATURES WILL PERSIST FOR FRIDAY...WITH HIGHS ONLY REACHING
THE UPPER 30S AND LOWER 40S.
BROAD SURFACE HIGH PRESSURE AND MID LEVEL TROUGHING WILL TRANSLATE
TO CONTINUED BELOW NORMAL TEMPERATURES THROUGH THE WEEKEND. HIGHS
WILL MAINLY RANGE FROM AROUND 40 TO 45 DEGREES ON SATURDAY AND
SUNDAY...WITH SUB-FREEZING LOWS. FRIDAY NIGHT APPEARS TO BE THE
COLDEST NIGHT OF THE WEEKEND...WHEN READINGS ARE EXPECTED TO DIP TO
BETWEEN 20 AND 25 DEGREES. MORE CLOUD COVER AND EVEN LIGHT SNOW
WILL BE POSSIBLE FOR SATURDAY NIGHT ACROSS WEST CENTRAL AND SOUTH
CENTRAL MN...AS A WEAK MID LEVEL WAVE CLIPS THE SOUTHERN HALF OF
THE STATE.
TEMPERATURES WILL SLOWLY MODERATE AT THE START OF THE UPCOMING
WEEK...WITH HIGHS IN THE MID 40S TO LOWER 50S BY WEDNESDAY.
&&
.AVIATION.../06Z TAF ISSUANCE/
THUNDERSTORMS HAVE DEVELOPED...BUT REMAIN PRIMARILY ALONG AND
AHEAD OF THE FRONT FROM NRN IA TO SWRN WI. A FEW MORE HAVE ALSO
FORMED NEAR THE TWIN CITIES AND NEW RICHMOND...BUT SHOULD NOT
PERSIST IN THOSE LOCATIONS FOR TOO LONG. THESE STORMS WILL
CONTINUE ON A SCATTERED BASIS FOR MUCH OF THE OVERNIGHT HOURS AND
AFFECT MAINLY EAU. FARTHER WEST...EXPECT WIDESPREAD RAIN TO DEVELOP
FROM SOUTHWEST TO NORTHEAST DURING THE OVERNIGHT HOURS AS AN
IMPULSE OVER THE PLAINS PUSHES NORTHEAST. STILL EXPECTING THE RAIN
TO TURN TO SNOW AT AXN...RWF...AND STC BETWEEN 09Z-12Z AS COLDER
AIR PUSHES SOUTHEAST. SOME SNOW MAY MIX WITH RAIN TOWARD LATE
MORNING AT MSP...EARLY AFTERNOON AT RNH...AND MID AFTERNOON NEAR
EAU. OTHERWISE...CONDITIONS WILL DETERIORATE TO IFR OR LIFR
CONDITIONS WITH THE RAIN AND SNOW BEFORE IMPROVING MARKEDLY BY
THURSDAY EVENING.
KMSP...A FEW STORMS HAVE FORMED SOUTHEAST OF THE TERMINAL...BUT
CONFIDENCE IS NOT HIGH ENOUGH WITH REGARDS TO PROXIMITY TO
INCLUDE THEM AS A VCTS IN THE TAF ATTM. STEADY RAIN WILL DEVELOP
LATE TONIGHT WITH IFR CONDITIONS PERSISTING THROUGH LATE
MORNING...THEN GRADUALLY IMPROVE THROUGH THE DAY AS DRIER AIR
MOVES IN. COULD SEE A FEW SNOWFLAKES MIX WITH THE RAIN BY EARLY
AFTERNOON.
/OUTLOOK FOR KMSP/
FRI...VFR. WINDS WNW 10G20KTS.
SAT...VFR. WINDS LGT AND VRB.
SUN...VFR. SLIGHT CHANCE -RASH. WINDS SE AT 5 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
LS/BORGHOFF
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
341 PM CDT Thu Oct 25 2012
.DISCUSSION...
Tonight through Saturday...
As precipitation exits the forecast area this afternoon, the main
focus for the short term will be temperatures, particularly tonight
and Friday night lows. Models don`t seem to have a good handle on
the widespread stratus building southward across portions of eastern
Nebraska and Iowa, which has the potential to strongly impact the
low temperature forecast tonight. Current water vapor imagery shows
some signs of developing subsidence behind the departing upper-level
jet streak in the eastern Dakotas; however, it is yet to be seen
whether this will translate to erosion of the low-level cloud field
this evening. Both the NAM and RAP do dry out first the midlevels
and eventually the low levels by 06z across southeast Nebraska and
into the forecast area, so have still continued a decreasing trend
in cloudiness tonight, leading to a cooler low temperature forecast
across the area. However, with some near-surface moisture remaining
and a more rapid temperature fall after 06z, do not think that a
freeze will be likely across the region even if clouds clear out
completely.
The setup on Friday night looks much more prototypical for a hard
freeze, with a 1032 mb surface high filtering into the central
Plains, pushing the surface ridge axis over northwest Missouri
shortly after midnight. Temperatures could easily drop into the mid
to upper 20`s across the majority of the region Saturday morning,
and would likely remain below freezing for several hours. If the
forecast remains on track, a freeze warning will be needed for areas
that have not already experienced a hard freeze this fall. The ridge
axis will remain over the region through early afternoon on
Saturday, keeping daytime temperatures 10 to 15 degrees below normal
in the upper 40s to lower 50s.
Laflin
Medium Range (Sunday through Thursday):
High forecast confidence this period as upper level flow remains
stagnant in the wake of a large downstream block formed by the
merging of an eastern trough and Hurricane Sandy into a potential
superstorm. This will maintain a steady northwest upper flow regime
over the regime which further amplify late in the period as
additional troughing builds into the Pacific Northwest.
All in all, precipitation chances are near zero through the period
and the effects of negative thermal advection vs. insolation will
generally offset each other. This will keep temperatures steady
through much of the week with highs in the low-mid 50s and lows in
the low-mid 30s.
Bookbinder
&&
.AVIATION...
For the 18Z TAFs, low level lift should shift eastward over the next
hour, ending the drizzle at the Kansas City terminals. Otherwise,
blustery conditions will continue with northwest winds gusting to
around 25 knots with widespread IFR ceilings through mid afternoon.
For ground crews, temps will hold steady in the mid 40s. Large scale
subsidence should overspread the terminals between 22 and 00Z,
allowing ceilings to lift to VFR and then scatter out.
Wind gusts should end by 01Z, with a northwest direction persisting
overnight as speeds decrease to 8-10 knots. Mainly clear skies
expected overnight into Friday morning.
Bookbinder
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
WFO EAX
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1207 AM CDT Thu Oct 25 2012
...UPDATED AVIATION DISCUSSION...
.DISCUSSION...
Today through Saturday...
In the short term, the primary focus will be precipitation chances
with a dynamic cold front approaching from the northwest. Although
most model solutions continue to indicate light, warm sector
precipitation across northwest Missouri this afternoon and evening,
and low level moisture is evident in the scattered to broken MVFR
deck, the weak forcing resulting from slight isentropic lift has not
been enough to produce rain showers ahead of the surface cold front.
Short range hi-res models have caught onto the lack of precipitation
this afternoon, and keep rainfall out of Missouri prior to 06z. Have
hedged a bit earlier than the latest HRRR forecasts in bringing a
chance of precipitation into far northwestern portions of the CWA
for the potential that storms could develop on the boundary and move
into the far northwest before 06z; however, the better chances for
showers and thunderstorms will be Thursday as the main trough axis
dips into southeast Nebraska and begins driving the surface front
more quickly to the southeast.
Both the NAM and GFS produce convective precipitation along the low
level boundary tonight as frontogenesis increases and midlevel
cooling supports temporarily higher lapse rates, mainly above 925mb.
The best chance for any robust storms to develop will likely be
confined to the period between 06z-09z when storms can be rooted
more closely to the surface; afterward, the low-level inversion will
be compounded by surface frontal passage, and the focus for
precipitation will shift a bit closer to the 850mb front. Most
precipitation during the daylight hours on Thursday should occur
mainly along the 850 front, with a small chance for some isolated
development along the surface front in far eastern portions of the
forecast area early Thursday afternoon. Rain chances will linger a
bit across the southeast as midlevel forcing broadens early Friday
evening, with any remaining showers expected to move out shortly
between 00z-06z Friday.
Temperatures will drop significantly behind the cold front, and in
general, highs will be reached just prior to frontal passage on
Thursday. Highs for Friday and Saturday will be well below average
as cold surface high pressure settles into the region, and lows
Friday night could drop a few degrees below freezing across areas
that have not previously received a hard freeze.
Laflin
Medium Range (Saturday Night through Wednesday)...
As the Canadian surface ridge remains settled over the area this
weekend...temperatures will dip to around 30 degrees Sunday morning.
The northern zones have experienced a hard freeze so will have to
make some decisions tomorrow about headlines for the southern three
quarters of the area for Sunday and possibly Monday mornings. The
500-1000mb thicknesses are around 537-540DM by Sunday morning with
very light winds and clear skies.
Lows on Monday morning may be a few degrees warmer as the surface
ridge slides further east. Not much in the way of advection at this
time though and the dry conditions with light winds...may require a
downward tweak of the lows for Monday morning. By Tuesday...we will
see the winds finally swing around to the south as the ridge moves
further east so there will be an increase in the thicknesses and 850
mb temps...therefore we should see above freezing temperatures on
Tuesday and Wednesday mornings.
Daytime highs through the extended will show a gradual warming trend
as well from the 40s on Sunday to the around 60 degrees F by Tuesday
and Wednesday.
Storm track remains well to the north so no precipitation is
expected through the period. Adolphson
&&
.AVIATION...
For the 06Z TAFs...strong cold front over southeast Nebraska and far
northwest MO will make very little southward push until later
tonight, and may not clear STJ until 10Z despite being just a few
miles away. Front will then accelerate through the remainder of
western and central MO through Thursday morning. Widespread IFR cigs
behind the front are likely to overspread all terminals through the
morning, and may be slow to lift and scatter through the afternoon.
Post-frontal convection is currently organizing and growing
widespread over KS/NE, but is forecast to weaken and decrease in
coverage by the time it reaches the KC terminals. Will therefore
continue to include only a VCTS for now, and will watch for
amendments to add thunder as needed.
Hawblitzel
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
WFO EAX
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
638 PM CDT FRI OCT 26 2012
.AVIATION...FOR THE KLBF AND KVTN TERMINALS THROUGH 00Z SUNDAY.
A LOW CONFIDENCE AVIATION FCST CONTINUES ACROSS WESTERN AND NORTH
CENTRAL NEBRASKA THIS EVENING THANKS TO PESKY STRATUS...WHICH
REMIANS IN PLACE ACROSS WESTERN AND NORTH CENTRAL NEBRASKA. BOTH THE
NAM AND GFS SOLNS CONTINUE TO HAVE A POOR HANDLE ON THE LOW LEVEL
MOISTURE FIELD AND UTILIZED THE RAP SOLN FOR CLOUD COVER THIS
EVENING INTO THE OVERNIGHT. THIS YIELDS BROKEN TO OVERCAST SKIES AON
2500 FT AGL AT THE KLBF TERMINAL AT LEAST THROUGH 09Z. AT THE KVTN
TERMINAL...SCATTERED CLOUDINESS IS EXPECTED AND SATELITE PICS ARE
INDICATING SOME LIMITED CLEARING ACROSS NWRN NEBRASKA. CIGS SHOULD
SCATTER OUT IN THE LOW LEVELS AT KLBF...HOWEVER...MID AND HIGH LEVEL
CLOUDINESS WILL CONTINUE TO STREAM INTO WESTERN AND NORTH CENTRAL
NEBRASKA FROM THE WEST...LEADING TO BROKEN CIGS AOA 10000 FT AGL
SATURDAY. LIGHT SOUTHWESTERLY WINDS WILL SHIFT TO THE SOUTH LATER
TONIGHT AND REMAIN IN THE 5 TO 10 KT RANGE. ON SATURDAY...WINDS WILL
SHIFT TO THE SOUTHWEST AND WEST AT AROUND 10 KTS AND REMAIN THERE
INTO THE AFTERNOON HOURS.
&&
.PREV DISCUSSION... /ISSUED 344 PM CDT FRI OCT 26 2012/
SYNOPSIS...
SURFACE HIGH PRESSURE CENTERED OVER MCCOOK NEBR. WEAK WINDS
CIRCULATING AROUND THE HIGH WITH CONSIDERABLE LOW AND MID CLOUDS
ACROSS THE REGION. DUE TO LACK OF MIXING AND SUN...TEMPERATURES
CONTINUE TO REMAIN CHILLY IN THE LOWER AND MID 30S. SOME CLEARING IN
THE PANHANDLE.
&&
.SHORT TERM...TONIGHT THROUGH MONDAY
LOW CLOUDS WILL THIN OUT ACROSS THE NORTHWEST THIS EVENING WHILE
LIKELY PERSISTING ACROSS THE SOUTHEAST. MEANWHILE...UPSTREAM
DISTURBANCE CURRENTLY LOCATED OVER NORTHERN IDAHO AND SOUTHWEST
MONTANA IS FORECAST TO MOVE SOUTHEAST BRINGING AN INCREASE IN MID
AND HIGH CLOUDINESS OVERNIGHT. THEREFORE THE BALANCE OF THE NIGHT TO
REMAIN MOSTLY CLOUDY. DESPITE SUCH COOL TEMPS THIS AFTERNOON IN THE
MID 30S...CLOUD COVER WILL HELP KEEP LOWS IN THE LOWER/MID 20S.
AS DISTURBANCE MOVES THROUGH WESTERN NEBRASKA SATURDAY...KEPT A
SLIGHT CHANCE FOR RAIN OR SNOW ACROSS NORTH CENTRAL NEBRASKA FOR THE
AFTERNOON/EVENING. THIS HAS BEEN INDICATED FAIRLY CONSISTENTLY BY
THE GFS...WHILE THE NAM...SREF AND ECMWF REMAIN MOSTLY DRY. MOSTLY
CLOUDY WITH HIGHS AGAIN TO RANGE BELOW NORMAL FROM NEAR 50 IN
SOUTHERN AREAS TO THE MID 40S NORTH CENTRAL.
UPPER RIDGING OCCURS ACROSS THE WESTERN CONUS SUNDAY...WHILE
NORTHWEST FLOW ALOFT STILL WILL EXIST ACROSS THE CENTRAL PLAINS.
WILL SEE A SLIGHT WARMUP DUE TO A RETURN FLOW OF LIGHT SOUTHERLY
WINDS AND HIGHS REACHING THE UPPER 50S FAR SOUTHWEST TO UPPER 40S
NORTHEAST.
MILDER YET FOR MONDAY. UPPER RIDGE TO ADVANCE FURTHER EAST INTO THE
CENTRAL ROCKIES WHILE NEGATIVELY TILTED UPPER TROUGH IN THE EASTERN
CONUS. A MORE PRONOUNCED LEESIDE TROUGH ALONG THE HIGH PLAINS. HIGHS
FROM UPPER 60S FAR SOUTHWEST TO UPPER 50S NORTHEAST.
.LONG TERM...TUESDAY THROUGH FRIDAY
HURRICANE SANDY FORECAST TO REACH THE MID ATLANTIC COAST EARLY
TUESDAY...SOMEWHERE NEAR OR NORTH OF THE DELMARVA PENINSULA. THIS
TO RESULT IN A BLOCKING PATTERN WITH AN UPPER RIDGE TO AMPLIFY
ACROSS THE CENTRAL CONUS THROUGH FRIDAY. DRY AND MILD CONDITIONS
THROUGH THURSDAY WITH HIGHS FROM THE UPPER 50S TO UPPER 60S ARE
LIKELY...INCLUDING HALLOWEEN DAY.
THERE WILL BE A WESTERN TROUGH WHICH MAY EITHER BECOME CLOSED OFF
NEAR THE FOUR CORNERS REGION PER GFS SOLUTION...OR AS AN OPEN WAVE
APPROACHING THE CENTRAL PLAINS PER THE ECMWF. HAVE A SLIGHT CHANCE
FOR RAIN SHOWERS FRIDAY AND HIGHS NEAR 60. MEDIUM RANGE MODEL
AGREEMENT COULD EVENTUALLY BRING ENHANCED CHANCES HOWEVER.
&&
.AVIATION...
CLOUD COVER CONTINUES TO BE PROBLEMATIC THIS AFTERNOON.
OVERALL...CEILINGS HAVE BEEN RISING ACROSS NEBRASKA AS THE AFTERNOON
PROGRESSES...HOWEVER SOME LOCATIONS HAVE SEEN A DROP IN CEILINGS
INTO THE MID AFTERNOON HOURS. HIGH PRESSURE AT THE SURFACE WAS
LOCATED OVER SOUTHWEST NEBRASKA AT 20Z WITH LOW LEVEL MOISTURE
CONTINUING TO STAY TRAPPED UNDER AN INVERSION AND ADVECTING
NORTHEAST ON THE BACKSIDE OF THE HIGH. BELIEVE THESE CLOUDS WILL
STAY IN PLACE UNTIL STRONGER WINDS ARE SEEN ACROSS THE AREA TO
ADVECT DRIER AIR INTO THE REGION. MODELS ARE INDICATING THIS
HAPPENING THIS EVENING. CONFIDENCE ISN/T HIGH WITH TIMING AND WILL
CONTINUE TO MONITOR. AN APPROACHING UPPER LEVEL DISTURBANCE SATURDAY
MORNING WILL CAUSE WINDS TO SWITCH TO THE SOUTH AND INCREASE BY LATE
MORNING. ALSO...MID AND UPPER LEVEL CLOUDS /ABOVE 8K FEET/ WILL
INCREASE AHEAD OF THIS SYSTEM LATE TONIGHT AND SATURDAY MORNING.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM/EXTENDED...ROBERG
AVIATION...BUTTLER
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
559 PM CDT THU OCT 25 2012
.AVIATION...
00Z TAF FOR KOMA...KOFK...KLNK
MODELS ARE HAVING A VERY DIFFICULT TIME WITH THE CLOUD FORECAST
OVERNIGHT. MOST MODELS WOULD INDC GENERALLY CLEAR SKIES WITH
DECREASING WINDS...BUT THIS APPEARS UNLIKELY GIVEN THE LARGE SC
DECK ACROSS...AND UPSTREAM FM THE AREA CURRENTLY. THUS WE WILL GO
WITH A PERSISTENCE FORECAST AT THIS TIME UNTIL MODEL FORECASTS
IMPROVE...OR CLEAR TRENDS IN OBSERVATION DATA DEVELOP. THUS WE
WILL HAVE MVFR CIGS AT ALL SITES THROUGH THE NIGHT. NORTHWEST
WINDS WILL BE DIMINISHING THROUGH THE NIGHT THOUGH AS THE PRESSURE
GRADIENT DECREASES.
BOUSTEAD
&&
.PREV DISCUSSION... /ISSUED 313 PM CDT THU OCT 25 2012/
SHORT TERM...TONIGHT THROUGH SUNDAY. MAIN FORECAST PROBLEM IN
THE VERY NEAR TERM IS AN EXPANDING DECK OF STRATUS THAT NO MODEL
EXCEPT THE RAP SEEMS TO BE HANDLING ALL THAT WELL. THUS...HAVE
TRENDED CLOUD GRIDS UPWARD TONIGHT...BUT AM STILL THINKING THAT
SOME OF THIS MAY DISSIPATE THIS EVENING AS MORE ANTICYCLONIC FLOW
CONTINUES TO TAKE HOLD ACROSS THE REGION. IT WILL PROBABLY BE A
COLD NIGHT WITH LOWS IN THE 20S AS SKIES SCATTER OUT. GIVEN THE
RECENT RAINS...THERE COULD BE PATCHY FOG OVERNIGHT...BUT PROBABLY
NOT A BIG ENOUGH OF CONCERN TO ADD TO THE GRIDS.
HIGH PRESSURE CONTINUES TO MOVE OFF THE HIGH PLAINS ON FRIDAY WITH
NORTHWESTERLY FLOW AND SOME MID AND HIGH CLOUDS. HIGH PRESSURE
DRIFTS OVER THE FORECAST AREA FRIDAY EVENING WITH A RETURN FLOW
SETTING UP ON SATURDAY.
A NEW AREA OF LOW PRESSURE DEVELOPS ACROSS SOUTHWEST SOUTH DAKOTA
THROUGH THE DAY SATURDAY WHILE AN UPPER WAVE MOVES THROUGH THE
NORTHERN PLAINS. WARM AIR ADVECTION COULD RESULT IN A FEW SHOWERS
NEAR THE SD/NE BORDER SATURDAY AFTERNOON...THEN SLIDING EAST
SOUTHEAST DOWN THE MISSOURI RIVER VALLEY SATURDAY NIGHT. THE NAM
IS CONSIDERABLY WARMER...WHICH IS PROBABLY TOO WARM. BUT...THERE
COULD BE A FEW RAIN SHOWER OR EVEN A SNOW FLAKE MIXED IN MAINLY
NORTH OF OMAHA SATURDAY NIGHT. DRY WEATHER IS EXPECTED ON SUNDAY.
LONG TERM...SUNDAY NIGHT THROUGH THURSDAY. MEDIUM RANGE MODELS
NOT SHOWING MUCH POTENTIAL FOR ANY PCPN THRU MOST OF NEXT WEEK.
OTHERWISE...LATEST GFS BLOCKING INDICES ADVERTISING UPSTREAM
BLOCKAGE DEVELOPING THRU DAY 7...ALLOWING FOR AMPLIFIED RIDGING
OVER THE ROCKIES/WRN HIGH PLAINS WITH 2 TROFS FLANKING THE CONUS.
THIS THEN LEADING TO THRUST OF COLD AIR DOWN THRU THE UPPER
MIDWEST/GREAT LAKES REGION REACHING ALL THE WAY DOWN TO THE SERN
STATES. AT THIS POINT THEN THE MAIN INTEREST IS HOW FAR WILL THE
WRN PERIPHERY OF CAA PUSH IT INTO THE CWA BEFORE AFOREMENTIONED
ROCKIES/WRN HIGH PLAINS RIDGE BUILDS IN. COMPARISON OF 1000-500MB
THKNS DAYS 5-7...ECM DETERMINIST PROGS CLEARLY SHOW IT TO BE THE
WARMER OF THE TWO. THIS ALSO REFLECTED THRU WARMER ECM MOS MAX/MIN
TEMPS RELATIVE TO THE MEX. GOING FCST APPEAR TO BE IN ACCORDANCE
WITH THE WARMER ECM SOLUTION...THUS SEE NO REASON TO MAKE ANY
CHANGE DEPICTING WARMING TREND IN THE EXTEND PDS.
DEE
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
313 PM CDT THU OCT 25 2012
.SHORT TERM...TONIGHT THROUGH SUNDAY. MAIN FORECAST PROBLEM IN
THE VERY NEAR TERM IS AN EXPANDING DECK OF STRATUS THAT NO MODEL
EXCEPT THE RAP SEEMS TO BE HANDLING ALL THAT WELL. THUS...HAVE
TRENDED CLOUD GRIDS UPWARD TONIGHT...BUT AM STILL THINKING THAT
SOME OF THIS MAY DISSIPATE THIS EVENING AS MORE ANTICYCLONIC FLOW
CONTINUES TO TAKE HOLD ACROSS THE REGION. IT WILL PROBABLY BE A
COLD NIGHT WITH LOWS IN THE 20S AS SKIES SCATTER OUT. GIVEN THE
RECENT RAINS...THERE COULD BE PATCHY FOG OVERNIGHT...BUT PROBABLY
NOT A BIG ENOUGH OF CONCERN TO ADD TO THE GRIDS.
HIGH PRESSURE CONTINUES TO MOVE OFF THE HIGH PLAINS ON FRIDAY WITH
NORTHWESTERLY FLOW AND SOME MID AND HIGH CLOUDS. HIGH PRESSURE
DRIFTS OVER THE FORECAST AREA FRIDAY EVENING WITH A RETURN FLOW
SETTING UP ON SATURDAY.
A NEW AREA OF LOW PRESSURE DEVELOPS ACROSS SOUTHWEST SOUTH DAKOTA
THROUGH THE DAY SATURDAY WHILE AN UPPER WAVE MOVES THROUGH THE
NORTHERN PLAINS. WARM AIR ADVECTION COULD RESULT IN A FEW SHOWERS
NEAR THE SD/NE BORDER SATURDAY AFTERNOON...THEN SLIDING EAST
SOUTHEAST DOWN THE MISSOURI RIVER VALLEY SATURDAY NIGHT. THE NAM
IS CONSIDERABLY WARMER...WHICH IS PROBABLY TOO WARM. BUT...THERE
COULD BE A FEW RAIN SHOWER OR EVEN A SNOW FLAKE MIXED IN MAINLY
NORTH OF OMAHA SATURDAY NIGHT. DRY WEATHER IS EXPECTED ON SUNDAY.
.LONG TERM...SUNDAY NIGHT THROUGH THURSDAY. MEDIUM RANGE MODELS
NOT SHOWING MUCH POTENTIAL FOR ANY PCPN THRU MOST OF NEXT WEEK.
OTHERWISE...LATEST GFS BLOCKING INDICES ADVERTISING UPSTREAM
BLOCKAGE DEVELOPING THRU DAY 7...ALLOWING FOR AMPLIFIED RIDGING
OVER THE ROCKIES/WRN HIGH PLAINS WITH 2 TROFS FLANKING THE CONUS.
THIS THEN LEADING TO THRUST OF COLD AIR DOWN THRU THE UPPER
MIDWEST/GREAT LAKES REGION REACHING ALL THE WAY DOWN TO THE SERN
STATES. AT THIS POINT THEN THE MAIN INTEREST IS HOW FAR WILL THE
WRN PERIPHERY OF CAA PUSH IT INTO THE CWA BEFORE AFOREMENTIONED
ROCKIES/WRN HIGH PLAINS RIDGE BUILDS IN. COMPARISON OF 1000-500MB
THKNS DAYS 5-7...ECM DETERMINIST PROGS CLEARLY SHOW IT TO BE THE
WARMER OF THE TWO. THIS ALSO REFLECTED THRU WARMER ECM MOS MAX/MIN
TEMPS RELATIVE TO THE MEX. GOING FCST APPEAR TO BE IN ACCORDANCE
WITH THE WARMER ECM SOLUTION...THUS SEE NO REASON TO MAKE ANY
CHANGE DEPICTING WARMING TREND IN THE EXTEND PDS.
DEE
&&
.AVIATION...18Z TAFS FOR KOMA...KLNK...AND KOFK.
EXTENSIVE STRATUS DECK CONTINUES TO SPILL SOUTHEAST FROM THE
DAKOTAS. WILL GO WITH MVFR CONDITIONS THROUGH THE ENTIRE TAF PERIOD.
NO MODEL DATA HAS A GOOD HANDLE ON CURRENT CLOUDS AND SO HAVE BASED
THE TAF FORECAST ON CURRENT TRENDS.
KERN
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
1000 AM EDT THU OCT 25 2012
.SYNOPSIS...
A BUILDING RIDGE OF HIGH PRESSURE BOTH ALOFT AND AT THE SURFACE WILL
RESULT IN DRY CONDITIONS AND MUCH ABOVE NORMAL TEMPERATURES FOR THE
REMINDER OF THIS WEEK. BY THE WEEKEND...AN APPROACHING COLD FRONT
WILL INCREASE THE CHANCES FOR PRECIPITATION...ALONG WITH COOLER
TEMPERATURES. THE REMNANTS OF TROPICAL SYSTEM SANDY COULD IMPACT THE
NORTH COUNTRY WITH RAIN AND WIND EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 1000 AM EDT THURSDAY...MINOR UPDATE TO SKY COVER THROUGH TODAY
TO ACCT FOR CURRENT OBSERVATIONAL DATA AND LATEST MID-LVL RH
PROGS....WHICH WOULD OFFER PTLY SUNNY ERN VT/SLV...AND MOSTLY
CLOUDY DACKS/CHVLY TODAY. ALSO OPTED TO CARRY AN OUTSIDE CHC OF A
SPRINKLE OR VERY LIGHT SHOWER ACROSS THE FAR NORTH...MAINLY NRN
SLV TODAY PER HRRR DATA AND RADAR SHOWING SOME LIGHT RETURNS NORTH
OF LAKE ONTARIO AS OF 14Z. PCPN AMNTS NEGLIGIBLE. REST OF FCST IN
GOOD SHAPE WITH HIGHS 50S TO AROUND 60 EAST...AND TO NEAR 70 SLV.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/...
AS OF 400 AM EDT THURSDAY...TONIGHT...SOUNDINGS SHOW RH DECREASING
ACRS OUR FA...AS LARGE SCALE SUBSIDENCE DEVELOPS FROM BUILDING
RIDGE. IN ADDITION...SOUTH TO SOUTHWEST FLOW WL DEVELOP...WHICH WL
HELP PUSH DEEPER RH/MOISTURE NORTH OF OUR CWA. IN
ADDITION...SOUNDINGS SHOW GOOD BL MIXING TONIGHT AS GRADIENT
INCREASES FROM APPROACHING COLD FRONT...ESPECIALLY CV/SLV. THIS WL
HELP KEEP TEMPS IN THE U40S TO L50S AT BTV...WITH MUCH COOLER
TEMPS IN DEEPER MTN VALLEYS...WHERE WINDS WL DECOUPLE AND SKIES WL
CLR. THINKING M/U30S PARTS OF THE NECK AND L/M 40S DACKS/CENTRAL
VT.
MID/UPPER LVL RIDGE CONTS TO BUILD ACRS OUR CWA ON FRIDAY AND
SHIFTS TO OUR EAST BY SATURDAY...AS TROF/COLD FRONT APPROACH OUR
FA. THE COMBINATION OF WARM SOUTHERLY WINDS AND PROGGED 85H TEMPS
NEAR 12C AN 925MB TEMPS OF 15C....SUPPORT HIGHS IN THE M60S
NECK/MTNS TO M70S CV/SLV ON FRIDAY. NEAR RECORD HIGH TEMPS WL BE
POSSIBLE ON FRIDAY ACRS THE NORTH COUNTRY. PLEASE SEE CLIMO
SECTION BLW FOR RECORDS. SOUNDINGS SHOW DEEP DRY LAYER...WHICH WL
RESULT IN PLENTY OF SUNSHINE ACRS OUR FA ON FRIDAY. NAM CONTS TO
SHOW LLVL RH INCREASE ACRS OUR CWA ON SOUTH TO SOUTHEAST FLW EARLY
SATURDAY MORNING...WITH THE POTENTIAL FOR A LOW STRATUS DECK
DEVELOPING. MEANWHILE...GFS IS MUCH DRIER WITH RH PROFILES...AND
KEEPS BEST RH ASSOCIATED WITH APPROACHING COLD FRONT. NAM/GFS IN
GOOD AGREEMENT WITH POSITION OF SFC BOUNDARY ACRS NORTHERN NY BY
18Z SAT AND ENTERING THE CV BY 00Z SUNDAY. GIVEN...RIBBON OF
BETTER 850 TO 500MB RH AND SOME AREAS OF ENHANCED UVVS...WL
MENTION LIKELY POPS WESTERN CWA AND CHC ELSEWHERE. LLVL THERMAL
GRADIENT TIGHTENS ACRS OUR FA ON SATURDAY...WITH TEMPS RANGING
FROM THE 60S EAST TO 50S WEST.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 400 AM EDT THURSDAY...BLOCKING PATTERN OVER THE CENTRAL ATLANTIC
TO HAVE AN IMPACT ON OUR WEATHER IN THE EXTENDED PERIOD FROM
SATURDAY NIGHT THROUGH THURSDAY. AT THIS TIME IT APPEARS THE UPPER
FLOW WILL BE BLOCKED THROUGH MUCH OF THE EXTENDED PERIOD AND THIS
MEANS IT WILL BE HARD TO HAVE WEATHER SYSTEMS PUSH EASTWARD. THIS
WILL HAVE PARTICULAR INTEREST FOR OUR AREA AS THIS MAY DRIVE WHERE
HURRICANE SANDY GOES. WHILE THERE ARE STILL DIFFERING SCENARIOS AS
TO HURRICANE SANDY`S PATH...ONE THING FOR SURE IS THAT IT WILL
MOVE NORTHWARD AND PHASE IN SOME WAY SHAPE OR FORM WITH UPSTREAM
UPPER LEVEL TROUGH. IT LOOKS LIKE THE MAIN TIME PERIOD THE IMPACTS
OF THIS SYSTEM WILL STILL BE MONDAY AND TUESDAY. THUS THE IDEA OF
RAIN LIKELY IN THE GOING FORECAST FOR MONDAY AND TUESDAY LOOKS
GOOD AND WILL NOT STRAY FROM THAT AT THIS POINT. GIVEN THE LONGER
DURATION OF RAIN AND THE MOISTURE BEING TROPICAL IN
NATURE...SYSTEM WILL HAVE TO BE WATCHED FOR ITS HEAVY RAIN
POTENTIAL. IN ADDITION...SYSTEM IS STRONG ENOUGH THAT GUSTY WINDS
WILL ALSO EXIST AND ATTENTION WILL BE PAID TO THE WEST SLOPES OF
THE GREEN MOUNTAINS AS THE EXPECTED TRACK OF THIS SYSTEM WOULD
ENHANCE THE POTENTIAL FOR DOWNSLOPE WINDS IN THIS AREA. WILL
UPDATE THE HAZARDOUS WEATHER OUTLOOK TO INDICATE THE POTENTIAL
REMAINS FOR HEAVY RAIN AND GUSTY WINDS EARLY NEXT WEEK. SYSTEM
WILL BE SLOW TO CLEAR THE AREA...SO GOING FORECAST OF A CHANCE OF
SHOWERS FOR WEDNESDAY LOOKS GOOD. COULD EASILY SEE THAT THREAT OF
PRECIPITATION CONTINUING RIGHT THROUGH THE END OF NEXT WEEK.
&&
.AVIATION /14Z THURSDAY THROUGH MONDAY/...
THROUGH 12Z FRIDAY...VFR CONDITIONS GENERALLY EXPECTED THROUGH
THE PERIOD. THE ONLY EXCEPTION TO THIS WILL BE AT KRUT WHERE MVFR
CEILINGS WILL EXIST DURING THE MORNING HOURS...OTHERWISE ANY
CEILINGS WILL GENERALLY BE AROUND 5000 FEET TODAY. SKIES SHOULD
GENERALLY BE CLEAR TONIGHT WITH SOME CLOUDS AROUND 1000 FEET...BUT
SHOULD NOT BE ENOUGH TO CALL A CEILING. WINDS WILL INCREASE OUT OF
THE SOUTH THIS MORNING...BUT SPEEDS WILL GENERALLY BE UNDER 15 KNOTS.
OUTLOOK 12Z FRIDAY THROUGH MONDAY...VFR CONDITIONS WL PREVAIL THRU
00Z SUNDAY...BEFORE APPROACHING SFC BOUNDARY INCREASES THE CLOUDS
AND CHCS FOR SHOWERS SAT NIGHT INTO SUNDAY. IN ADDITION...SOUTHEAST
FLOW AROUND HIGH PRESSURE...MAY PRODUCE SOME LOW CLOUDS AND MVFR
CONDITIONS AT MPV SATURDAY NIGHT/SUNDAY MORNING. THE HEAVIER
SHOWERS ON SUNDAY WL BE CAPABLE OF PRODUCING BRIEF PERIODS OF MVFR
IN LOW CIGS/VIS. COASTAL LOW MAY BRING MVFR/IFR COND WITH STRONG
WIND COND...WITH POSSIBLE LLWS.
&&
.CLIMATE...
BELOW ARE RECORD HIGH TEMPS FOR FRIDAY 10/26/12:
BTV 75 1963
MSS 72 1963
MPV 74 1991
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...TABER
NEAR TERM...JMG/TABER
SHORT TERM...TABER
LONG TERM...EVENSON
AVIATION...EVENSON/LOCONTO
CLIMATE...WFO BTV
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1000 PM EDT FRI OCT 26 2012
.SYNOPSIS...
HIGH PRESSURE WILL WEAKEN AND RETREAT NORTH AS SANDY MOVES TO THE
NORTH AND NORTHEAST...OFFSHORE OF THE CAROLINAS. THE INFLUENCE OF
SANDY WILL CONTINUE OVER THE REGION AT LEAST INTO EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH SATURDAY/...
AS OF 1000 PM FRIDAY...
THE FIRST OUTER RAINBAND ASSOCIATED WITH HURRICANE SANDY...WHICH IS
EAST OF VERO BEACH FL THIS EVENING... HAS PUSHED NORTHWEST TO JUST
OFF THE SC COAST AS DRY AIRS INFILTRATES THE SYSTEM FROM THE SOUTH.
HOWEVER...THE BAND IS ESSENTIALLY STATIONARY WITH INDIVIDUAL SHOWERS
MOVING SOUTHWEST...PARALLEL TO THE CAROLINA COASTLINES AND LITTLE
PRECIP ONSHORE. THERE HAVE BEEN A FEW ISOLATED POCKETS OF LIGHT
RAIN MOVING INLAND ACROSS THE NC COASTAL PLAIN THIS EVENING...MAKING
AS FAR WEST AS THE TRIANGLE AS OF 01Z. THE RAP INDICATES THIS VERY
LIGHT PRECIP WILL PUSH WEST TOWARD THE TRIAD OVERNIGHT AS THE FLOW
VEERS SLIGHTLY TO EASTERLY BETWEEN 925MB AND 850MB ...WITH
ADDITIONAL UPSLOPE PRECIP ALONG THE MOUNTAINS BY DAYBREAK.
OTHERWISE...THE SLOW MOVEMENT OF HURRICANE SANDY...ALONG WITH A WEAK
DRY AIR RIDGE EXTENDING SOUTH FROM ENGLAND INTO THE PIEDMONT WILL
KEEP AREAS WEST OF I-95 DRY OVERNIGHT. OVERALL...THERE HAS BEEN A
SMALL EASTWARD SHIFT AMONG THE OPERATIONAL MODELS REGARDING
SANDY...AND ACCORDINGLY A SIMILAR SHIFT IN THE PRECIP/NO PRECIP
LINE. THUS...THERE IS NO NEED TO ALTER THE OVERNIGHT POPS VERY
MUCH...AND SUBSEQUENT SHIFTS MAY NEED TO TRIM POPS ON THE WESTERN
EDGE IF THE GUIDANCE TREND CONTINUES TONIGHT.
TO THE WEST...THE SURFACE COLD FRONT HAS BEEN MAKING SLOW PROGRESS
TOWARD THE WESTERN SLOPES OF THE MOUNTAINS AND NOW EXTENDS FROM NEAR
BIRMINGHAM TO KNOXVILLE TO EAST OF PITTSBURGH. THERE IS VERY
LITTLE PRECIP WITH THE FRONT...OUTSIDE OF AN AREA OF ANAFRONTAL
PRECIP OVER THE EASTERN GREAT LAKES. THE FRONT WILL CONTINUE TO
SLOW OVERNIGHT AND EVENTUALLY CROSS THE MOUNTAINS LATER SATURDAY AS
IT BECOMES ABSORBED INTO THE FLOW AROUND SANDY. AHEAD OF THE
FRONT...LOWS TONIGHT WILL BE SOMEWHAT MILD...MOSTLY UPPER 50S TO
LOWER 60S. HAVE TWEAKED LOWS IN THE SOUTHEAST A COUPLE DEGREES
BASED ON CURRENT READINGS. EXPECT MAINLY STRATUS IN THE EAST WITH A
SLOWLY INCREASING NORTH-NORTHEASTERLY WIND TO 10-15 MPH IN THE
SOUTHEAST BY 12Z SATURDAY. -BLS
SATURDAY:
THE FORECAST TRACKS FOR HURRICANE SANDY THROUGH 00Z SUNDAY BASED ON
THE 00Z ECMWF AND THE 12Z GFS ARE PRETTY SIMILAR...WITH THE GFS
STILL A LITTLE FARTHER EAST. HOWEVER...THE LITTLEST CHANGE IN TRACK
TO THE EAST OR WEST WILL HAVE A BIG IMPACT ON THE PRECIPITATION
FORECAST FOR SATURDAY. THE LATEST FORECAST FROM THE ECMWF (HPC`S
PREFERENCE) HAS MOVED THE TRACK OF SANDY WEST AGAIN AND IS ONE OF
THE WETTEST SOLUTIONS FOR CENTRAL NC. GIVEN THAT THERE IS STILL SOME
UNCERTAINTY WITH REGARD TO THE TRACK...HAVE MADE LITTLE CHANGE TO
THE PRECIP CHANCES SATURDAY. WITH SANDY TRACKING APPROXIMATELY
PARALLEL...AND A FEW HUNDRED MILES OFFSHORE OF THE ATLANTIC
COAST...THE BEST CHANCES FOR PRECIP WILL BE ALONG THE NC COAST AND
DECREASING FROM EAST TO WEST. HAVE INCREASED PRECIP AMOUNTS EAST OF
I-95. WITH THE STRONG PRESSURE GRADIENT OVER THE AREA...WINDS WILL
ALSO BE SIGNIFICANT...MAINLY NNE...SUSTAINED OF 15 KTS WITH GUSTS OF
30-35 KTS ACROSS THE SOUTH AND EAST AND SUSTAINED NEAR 12 WITH GUSTS
OF 20-30 KTS FROM RALEIGH WEST. AS WITH THE RAIN...WINDS WILL ALSO
INCREASE FROM WEST TO EAST. THE COLD FRONTAL PASSAGE WILL BE MASKED
BY THE COASTAL SYSTEM...BUT COMBINED WITH THE CLOUD COVER AND
PRECIP...WILL RESULT IN HIGHS SATURDAY IN THE 60S.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/...
AS OF 255 PM FRIDAY...
SATURDAY NIGHT THROUGH SUNDAY NIGHT...
MODEL GUIDANCE IN GENERALLY GOOD AGREEMENT WITH THE WELL OFFSHORE
TRACK OF TROPICAL CYCLONE SANDY... PARALLELING THE SE U.S. COAST
THROUGH SUNDAY MORNING...THEN THE NC COAST SUNDAY INTO SUNDAY NIGHT.
ECMWF IS MUCH STRONGER (AS MUCH AS 15-18MB) COMPARED TO THE GFS.
PAST PERFORMANCE OF THE ECMWF WITH TROPICAL SYSTEMS SUGGEST THAT THE
ECMWF MAY BE WAY TOO STRONG/DEEP WITH SANDY. AT 18Z...THE 00Z ECMWF
VERIFIED 7MB TOO DEEP. THIS MODEL FLAW MAY COME INTO PLAY CONCERNING
PRECIP AMOUNTS AND WIND INTENSITY OVER THE COASTAL PLAIN OF NC.
EXPECT THE STRONGEST WINDS CAUSED BY THE PRESSURE GRADIENT BETWEEN
AN CANADIAN HIGH OVER ONTARIO AND TC SANDY TO AFFECT OVER EASTERN
COUNTIES LATE SATURDAY NIGHT THROUGH SUNDAY NIGHT. USED THE NHC TCM
WINDS WITH A REDUCTION OF 30 PERCENT DUE TO LAND FRICTION. GUSTS
ACHIEVED UTILIZING THE LATEST RESEARCH PERFORMED BY C*STAR
INITIATIVE CONCERNING TROPICAL WIND FORECASTING. WIND GUSTS 35-40
MPH HIGHLY PROBABLE OVER SECTIONS OF THE COASTAL PLAIN. A LITTLE
EARLY TO ISSUE A WIND ADVISORY AT THIS TIME BUT IF THE SCENARIO
REMAINS THE SAME...AN ADVISORY MAY BE NECESSARY FOR SATURDAY NIGHT
THROUGH SUNDAY EVENING.
STILL APPEARS THAT PRECIP WILL BECOME WIDESPREAD OVER THE EAST HALF
OF CENTRAL NC BY SATURDAY AFTERNOON-EARLY EVENING AS A STRONG UPPER
JET OVER THE GREAT LAKES AND A DECENT MID LEVEL S/W CROSSING THE OH
VALLEY INCREASES MID LEVEL LIFT IN THE MOIST AIR MASS ON THE NW
QUADRANT OF SANDY. EXPECT THIS PRECIP BAND TO DRIFT SLOWLY ENE
SATURDAY NIGHT INTO EARLY SUNDAY.
MODELS DIVERGE AFTER 12Z SUNDAY WITH THE GFS TAKING SANDY FARTHER
OFFSHORE THAN ECMWF WITH A DISTINCT DRYING TREND OVERSPREADING
CENTRAL NC FROM THE SW. THE ECMWF MAINTAINS A WELL DEFINED MID LEVEL
TROUGH OVER THE NORTHERN COASTAL PLAIN ALONG WITH STRONG UPPER
DIVERGENCE SUPPLIED BY A 140+ JET OVER THE EASTERN GREAT LAKES.
CONFLUENCE ALONG THIS MID LEVEL TROUGH WOULD SUGGEST A CONTINUED
THREAT FOR MODERATE TO LOCALLY HEAVY RAIN OVER THE NORTHERN COASTAL
PLAIN. HOWEVER...SINCE THE ECMWF LIKELY TOO DEEP/STRONG WITH THE
SYSTEM...CONFLUENCE ALONG TROUGH MAY BE OVERDONE. DUE TO THE
CONSISTENCY OF THE ECMWF...HAVE LEANED HEAVILY TOWARD PER TRACK AND
WEATHER DEPICTION BUT THINK THAT ITS RAINFALL PRODUCTION OVERBLOWN
BY A FACTOR OF 2. THUS EXPECT RAINFALL AMOUNTS LATE SATURDAY THROUGH
SUNDAY AFTERNOON BETWEEN 1 AND 3 INCHES EAST OF HIGHWAY 1 WITH THE
HIGHEST AMOUNTS IN VICINITY OF THE NORTHERN COASTAL DUE TO PRESENCE
OF LINGERING MID LEVEL TROUGH.
LITTLE CHANGE IN TEMPS THIS PERIOD FROM THE PREVIOUS FORECAST.
EXPECT NOTICEABLY COOLER CONDITIONS AREAWIDE SUNDAY INTO SUNDAY
NIGHT.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 255 PM FRIDAY...
MONDAY THROUGH FRIDAY...
SANDY WILL BE THE DOMINATE WEATHER FEATURE THIS PERIOD. MODEL
GUIDANCE STILL OFFERING VARYING SOLUTIONS. ECMWF HAS BEEN THE MOST
CONSISTENT WHILE THE GFS HAS SHOWN SOME RUN-TO RUN VARIANCE. WILL
BASE BULK OF FORECAST ON THE ECMWF WITH ADJUSTMENT DUE TO EXPECTED
POSITION AND STRENGTH.
S/W IN THE NORTHERN STREAM WILL ATTAIN A NEGATIVE TILT AND DRAW
SANDY NWWD. ECMWF DOES THIS ABOUT 24 HOURS SOONER COMPARED TO THE
12Z GFS...DRAWING SANDY INTO THE CHESAPEAKE BAY REGION MONDAY WHILE
THE 12Z GFS HAS ITS WWD MOVEMENT MONDAY NIGHT INTO
TUESDAY...ALLOWING SANDY TO MOVE FARTHER NORTH BEFORE SWINGING INTO
SOUTHERN NEW ENGLAND.
WITH SANDY PROJECTED TO LIE TO OUR NORTH...EXPECT CONTINUED WNW
FLOW ACROSS OUR REGION THROUGH AT LEAST WEDNESDAY. DEEP CYCLONIC
CURVATURE WILL LIKELY MAINTAIN CLOUDINESS AND PATCHES OF RAIN OVER
OUR FAR N-NE COUNTIES MONDAY THROUGH TUESDAY ALONG WITH BREEZY/WINDY
CONDITIONS. FARTHER SOUTH...DOWNSLOPE COMPONENT OF THE LOW-MID LEVEL
WINDS SHOULD AID TO SCOUR OUT THE MOISTURE AND LEAD TO CLEARING
SKIES OVER THE SOUTHERN PIEDMONT-SANDHILLS AND SOUTHERN COASTAL
PLAIN. LOW LEVEL FLOW WILL ALSO ADVECT MUCH COOLER AIR INTO CENTRAL
NC. LOW LEVEL THICKNESSES CLUSTER AROUND 1295-1300M BOTH TUESDAY
MORNING AND WEDNESDAY MORNING. HISTORICALLY...THESE VALUES SUGGEST
MIN TEMPS IN THE UPPER 20S TO LOWER 30S. THICKNESSES HAVE TRENDED
SLIGHTLY WARMER COMPARED TO 24-48 HOURS AGO. IN ADDITION...STRONG
MIXING AND POSSIBILITY OF CLOUDINESS SHOULD KEEP TEMPS UP. MAY SEE
BETTER POTENTIAL FOR A LIGHT FREEZE IN SECTIONS OF THE PIEDMONT
EARLY WEDNESDAY AND/OR THURSDAY MORNING AS SURFACE WINDS MAY HAVE A
BETTER CHANCE TO DECOUPLE AND SKIES MAY BE CLEAR. OTHERWISE WITH
THICKNESSES AS MUCH AS 50M BELOW NORMAL...EXPECT MAX TEMPS 12-18
DEGREES BELOW NORMAL MONDAY-WEDNESDAY WITH SOME MODIFICATION
THURSDAY INTO FRIDAY. AFTERNOON TEMPS IN THE 50S EXPECTED FOR MOST
OF NEXT WEEK WITH SOME UPPER 40S PROBABLE TUESDAY ACROSS THE NW
PIEDMONT.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
AS OF 840 PM FRIDAY...
24 HOUR TAF PERIOD:
VFR CONDITIONS FROM LATE THIS AFTERNOON INTO THE EVENING ARE ALREADY
TAKING A TURN BACK INTO THE MVFR/IFR RANGE THIS EVENING... IN
GENERALLY AN EAST TO WEST FASHION. EXPECT THIS TREND TO CONTINUE...
AS HURRICANE SANDY (CURRENTLY LOCATED OFF THE FL COAST) SLOWLY LIFTS
NORTH-NORTHEASTWARD... KEEPING A MOIST NORTHEASTERLY LOW LEVEL FLOW
ACROSS CENTRAL NC. A FEW SHOWERS WELL IN ADVANCE OF SANDY MAY MOVE
ACROSS EASTERN PORTIONS OF THE AREA FROM TIME TO TIME THIS EVENING
INTO THE OVERNIGHT AS WELL. EXPECT GENERALLY MVFR/VFR CIGS AND
VISBYS THIS EVENING TO LOWER INTO AT LEAST THE IFR RANGE
OVERNIGHT... WITH POSSIBLY SOME LIFR CIGS AFTER MIDNIGHT TO AROUND
SUNRISE (HIGHEST PROBABILITY OF IFR CONDITIONS ACROSS THE EASTERN
TAF SITES... KRDU/KFAY/KRWI). EXPECT LOW CIGS TO SLOWLY IMPROVE
AGAIN ON SATURDAY AFTER SUNRISE... ALONG WITH INCREASING WINDS AS
SANDY SLOWLY LIFTS NNE`WARD HELPING TO INCREASE THE MSLP GRADIENT
ACROSS OUR AREA. THIS WILL LEAD TO SUSTAINED WINDS IN THE 15 TO 20
MPH RANGE BY AFTERNOON... WITH GUSTS AS HIGH AS 25 TO 33 MPH
(PERHAPS 35-40 MPH IN THE HEAVIEST RAIN BANDS) ACROSS EASTERN
PORTIONS OF THE AREA (MAINLY KRWI AND KFAY). WITH REGARD TO CHANCES
FOR RAIN ASSOCIATED WITH THE APPROACHING TROPICAL SYSTEM... EXPECT
RAIN CHANCES TO INCREASE EASTERN PORTIONS OF THE AREA... MAINLY
AFTER SUNRISE SATURDAY. MODEL GUIDANCE HAS SHIFTED THE AXIS OF RAIN
A BIT TO THE EAST FOR SATURDAY THAN PREVIOUSLY INDICATED. THUS...
KFAY AND KRWI WILL STAND THE BEST CHANCE OF SEEING THE WORST
AVIATION CONDITIONS... PERHAPS REMAINING MVFR ALL DAY... WITH
PERIODS OF RAIN. FARTHER WEST AT KGSO AND KINT EXPECT A GENERALLY
DRY DAY... WITH CIGS SLOWLY LIFTING TO VFR BY AFTERNOON. KRDU...
APPEARS TO BE CAUGHT IN BETWEEN. HOWEVER... FOR NOW WILL CONTINUE TO
LEAN TO A MORE PESSIMISTIC FORECAST FOR KRDU... SHOWING PREDOMINATE
RAIN... WITH CIGS ONLY LIFTING TO THE MVFR CATEGORY BY AFTERNOON.
LOOKING AHEAD:
ADVERSE AVIATION CONDITIONS WILL BE POSSIBLE THROUGH AT LEAST SUNDAY
NIGHT (ESPECIALLY ACROSS EASTERN/NORTHEASTERN PORTIONS OF THE AREA).
THERE IS STILL SOME UNCERTAINTY WITH REGARD TO THE TRACK OF
HURRICANE SANDY...WHICH WOULD IMPACT THE LOCATION AND DURATION OF
THE ADVERSE AVIATION CONDITIONS ACROSS THE AREA. BEST CHANCES FOR
HEAVY RAIN WILL BE AT KRWI...AND POSSIBLY AT KFAY AND KRDU. STRONG
GUSTY WINDS FROM THE NNE ARE LIKELY AREAWIDE BUT ESPECIALLY AT
KRDU/KRWI/KFAY... AND LOW LEVEL WIND SHEAR AND/OR SIGNIFICANT
MECHANICAL TURBULENCE IS ALSO POSSIBLE. VFR CONDITIONS ARE EXPECTED
TO RETURN MONDAY... HOWEVER WINDY CONDITIONS MAY PERSIST.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DJF
NEAR TERM...KC/BLS
SHORT TERM...WSS
LONG TERM...WSS
AVIATION...BSD/CBL
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1148 PM CDT WED OCT 24 2012
.DISCUSSION...LATEST FOG/STRATUS IMAGERY LOOP ALONG WITH SURFACE
OBSERVATIONS SHOW A SWATH OF STRATUS ACROSS NORTHERN NORTH DAKOTA.
THE RUC 925MB RH FIELD SEEMED TO HAVE THIS HANDLED WELL...MOVING
THIS AREA SOUTHEAST OVERNIGHT. CONCUR WITH THIS...ESPECIALLY AS
THE UPPER TROUGH/MAXIMUM CYCLONIC CURVATURE NOW CENTERED IN THE
WEST MOVES INTO CENTRAL NORTH DAKOTA BY 12Z THURSDAY. FOR THE REST
OF TONIGHT...DUE TO WIDESPREAD STRATUS HAVE WARMED MINIMUM TEMPERATURES
INTO THE UPPER 20S IN THE FAR WEST AND MID 20S SOUTHWEST. ALSO WITH
UPSTREAM CANADIAN SURFACE OBS SHOWING FLURRIES...HAVE ADDED THAT INTO
THE NORTH CENTRAL OVERNIGHT.
A COLD H85 POCKET OF AIR AS DENOTED BY THE -8C IN SOUTHERN
SASKATCHEWAN AND EASTERN MONTANA WILL GRADUALLY SHIFT SOUTHEAST
LATER TONIGHT INTO EARLY THURSDAY. THIS WILL PROMOTE MORE INSTABILITY
THURSDAY WITH POSSIBLE FLURRIES IN THE NORTH. WILL MAINTAIN THIS
IN THE FORECAST. OTHERWISE DRY AND COLD ELSEWHERE.
&&
.AVIATION...LOW PRESSURE ACROSS MANITOBA WILL MOVE EAST AND MAINTAIN
A COOL/BRISK TO WINDY NORTHWEST FLOW THROUGH THURSDAY. WIDESPREAD
MVFR CIGS ACROSS THE NORTHERN AERODROMES WILL CONTINUE TO MOVE
SOUTH THROUGH 12Z THURSDAY. EXPECT A GRADUAL LIFTING AND DETERIORATION
OF THE MVFR CIGS THURSDAY MORNING INTO THE EARLY AFTERNOON. NORTHWEST
WINDS WILL INCREASE WITH SUSTAINED WINDS BETWEEN 20 AND 25 MPH...AND
GUSTS TO 35 MPH THURSDAY AFTERNOON.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
DISCUSSION...KS
AVIATION...WAA
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1029 PM EDT FRI OCT 26 2012
.SYNOPSIS...
A COLD FRONT WILL MOVE INTO THE REGION BEFORE DISSIPATING ON
SATURDAY. TROPICAL CYCLONE SANDY WILL MOVE NORTH ACROSS THE OFFSHORE
ATLANTIC WATERS INTO MONDAY DEVELOPING INTO A POWERFUL NOR-EASTER.
THIS WILL RESULT IN UNSEASONABLY CHILLY AND WINDY CONDITIONS OVER
THE AREA MONDAY THROUGH WEDNESDAY.
&&
.NEAR TERM /THROUGH SATURDAY/...
AS OF 1030 PM EDT...REMOVED PRECIP CHANCES IN THE MTNS FOR THE
OVERNIGHT HOURS. 23Z HRRR RUN SHOWS THE LIGHT PRECIP BEHIND THE
FRONT ACROSS MIDDLE TN BUT KEEPS THE SHOWERS THERE...WITH NO
DEVELOPMENT SEEN AHEAD OF IT. 00Z NAM SUGGESTS THE FRONT WILL NOT
MAKE IT TO THE MTNS UNTIL LATE MORNING SO POP TREND WAS SLOWED
GREATLY.
AS OF 915 PM EDT...WILL MAINTAIN PREVIOUS FCST FOR LOW TEMPS TONIGHT
AS THERE WAS LITTLE CHANGE BETWEEN 12Z AND 18Z RUNS. MONITORING LOW
STRATUS AND SHOWERS BOTH NEAR THE COLD FRONT /MIDDLE TN/ AND IN THE
MOIST REGION UPSTREAM IN EASTERLY FLOW /ERN NC/. THE ONGOING LIGHT
SHOWERS IN THE VICINITY OF RDU WOULD REACH THE NC PIEDMONT AROUND
04Z IF THEY HOLD TOGETHER. MOISTURE DOES KEEP INCREASING AND THE
STEADY EASTERLY FLOW SHOULD CONTINUE SO THAT IS PLAUSIBLE. WILL
BRING UP THE ONSET TIME TO 04Z OVER DAVIE/ROWAN/CABARRUS...THOUGH IF
THE SHOWERS MAKE IT THERE IN THIS STATE THEY WILL PROBABLY ONLY GET
SPRINKLES.
AS OF 730 PM EDT...EASTERLY FLOW IN THE MIDLEVELS ALONG WITH
INCREASING MOISTURE IN THE LAYER WILL PROMOTE CLOUD AND PRECIP
DEVELOPMENT IN THE LATE OVERNIGHT HOURS OVER THE NC PIEDMONT. THE
BOUNDARY LAYER ALSO MOISTENS IN THAT AREA...ENABLING LOW STRATUS TO
ALSO FORM. AT THE PRESENT TIME POPS OVER THE PIEDMONT LOOK A LITTLE
TOO LOW AND SO THEY WILL BE INCREASED AND EXPANDED WESTWARD. ON
ANOTHER NOTE...COLD FRONT IS ADVANCING RATHER SLOWLY ACROSS THE TN
VALLEY AND MODEL DEPICTED FORCING IS NOT PARTICULARLY IMPRESSIVE
WITH IT OVER THE MOUNTAINS TONIGHT. WILL LOWER CHANCES TO SLIGHT
UNTIL MORNING.
AS OF 430 PM EDT...DELAYED ONSET OF PRECIP CHANCES IN THE MTNS BY A
COUPLE OF HOURS AND CONFIDENCE IS FAIRLY LOW THAT THE AREA WILL SEE
ANY SHOWERS AT ALL. CONVERGENCE LINE NEAR THE COLD FRONT OVER
CUMBERLAND PLATEAU IS PRODUCING A BAND OF CUMULUS BUT NO RADAR
RETURNS INDICATIVE OF PRECIP. MESO MODELS EITHER KEEP THE MTNS DRY
INTO THE EVENING OR SHOW DIURNALLY DRIVEN SHOWERS WHICH NOW SEEM
UNLIKELY GIVEN SATELLITE IMAGERY SHOWING THE CU OVER THE MTNS
FLATTENING OUT. UPDATED SKY TRENDS TO BETTER REPRESENT CIRRUS OVER
THE PIEDMONT...GENERALLY LEANING SUNNIER THE REMAINDER OF THE
AFTERNOON...THOUGH MAINTAINED INCREASING CLOUDS THIS EVENING.
AS OF 230 PM EDT...HURRICANE SANDY WILL MOVE NORTHWARD OFFSHORE OF
THE SE COASTLINE TONIGHT THROUGH SATURDAY...GRADUALLY STRENGTHENING
THE PRESSURE GRADIENT AND NRLY FLOW ACROSS THE REGION. MEANWHILE...A
BROAD TROUGH OF LOW PRESSURE EXTENDING SWD FROM A DEEPENING
MANITOBA/ONTARIO VORTEX WILL MAINTAIN A TROUGH AXIS W OF THE
APPALACHIANS THROUGH THE PERIOD. AN ASSOCIATED COLD FRONT CURRENTLY
STRETCHING FROM KJKL TO KCSV WILL MOVE SLOWLY EWD ACROSS EXTREME ERN
TN TONIGHT AND THEN STALL ACROSS THE SRN APPLACHIANS ON SAT.
AHEAD OF THE APPROACHING BOUNDARY...THE MODELS WRING OUT ISOLD TO
SCT SHOWERS IN THE SW MTNS IN CONVERGENT BL FLOW WITH SFC BASED CAPE
VALUES OF 300 TO 500 J/KG INTO THE EARLY EVENING THERE. THIS SEEMS
REASONABLE. THE FORCING REMAINS SOMEWHAT LIMITED ALONG THE STALLING
BOUNDARY LATE TONIGHT THROUGH SAT...BUT CONTINUED WEAK LLVL
CONVERGENCE COMBINED WITH IMPROVING UPPER DIVERGENCE SUPPORTS SCHC
TO CHC POPS IN AND NEAR THE MTNS. FARTHER E...LOW LEVEL NE FLOW
SHOULD ADVECT IN ANOTHER STRATUS LAYER FROM THE NE OVERNIGHT. AN
OUTER BAND OF TROPICAL RAIN SHOWERS AROUND THE SANDY CIRCULATION
COULD DEVELOP OVER THE CAROLINA PIEDMONT TONIGHT AND WRAP WWD TOWARD
THE INTERSTATE 77 CORRIDOR THROUGH SAT. WILL FEATURE MAINLY SCHC
POPS OVER ERN PIEDMONT SECTIONS ON SAT. THE PRES GRADIENT WILL ALSO
BE TIGHTEST ACROSS THE PIEDMONT...WITH GUSTY CONDITIONS LIKELY
DEVELOPING ALONG THE I-77 CORRIDOR SAT AFTN. THE DIURNAL TEMP RANGE
SHOULD BE SMALLER THAN IN RECENT DAYS...WITH WARM MINS TONIGHT...AND
COOLER MAXES SAT.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH TUESDAY/...
AS OF 245 PM FRIDAY...THE OPERATIONAL GUIDANCE CONTINUES TO AGREE ON
THE LARGE SCALE FEATURES...BUT CONTINUE TO DISAGREE ON THE EVENTUAL
TRACK OF SANDY AND ITS ASSOCIATED EXTRATROPICAL LOW. THE ENSEMBLE
MEANS HOWEVER...ARE IN MUCH BETTER AGREEMENT WITH EACH OTHER AND THE
OFFICIAL FORECAST TRACK FROM NHC/HPC. THE CURRENT FCST TRACK CURVES
THE CIRCULATION OFF THE CAROLINA COAST THEN INLAND NEAR THE DELAWARE
BAY TUE MORNING. WE WILL STILL SEE SOME EFFECTS FROM THIS STORM EVEN
THO IT REMAINS RELATIVELY FAR AWAY FROM OUR CWFA. THAT SAID...THE
COLD FRONT MOVING INTO THE WRN CWFA WILL PLAY A BIGGER PART IN
PRECIP CHANCES SAT NITE AND SUN. EXPECT SCT SHRA TO CONTINUE OVER
THE MTNS AND NC FOOTHILLS SAT EVENING...WITH ISOLATED SHRA
ELSEWHERE. THESE SHRA DIMINISH OVERNIGHT WITH THE BEST CHC
RETREATING TO THE TN BORDER BY SUN MORNING. SHRA WILL LINGER THERE
THRU THE DAY EVEN AS THE FRONT DISSIPATES IN THE LINGERING LOW LEVEL
MOISTURE...STRENGTHENING NWLY FLOW AND INCREASING FORCING AS SHORT
WAVE MOVES ACROSS THE AREA. SUNDAY WILL BE BREEZY ALL AREAS AS WELL.
SAT NITE WILL STILL BE WARM BEFORE THE COLD AIR MOVES IN WITH LOWS
UP TO 5 DEGREES ABOVE NORMAL. THE COLD AIR BEGINS MOVING IN SUN WITH
HIGHS 10 DEGREES BELOW NORMAL ACROSS THE MTNS AND A FEW DEGREES
BELOW ELSEWHERE.
COLD AIR RUSHES IN BEHIND THIS SYSTEM SUN NITE AND MON AS SANDY
BEGINS ITS TURN TO THE NW AND TRANSITIONS TO AN EXTRATROPICAL LOW.
LINGERING LOW LEVEL MOISTURE AND INCREASING CAA AND NWLY FLOW WILL
KEEP SCT SHRA ALONG THE TN BORDER SUN NITE THEN DIMINISHING COVERAGE
MONDAY. SOME OF THIS PRECIP WILL FALL AS SNOW...ESPECIALLY ABOVE
3500 FT...BUT SOME OF THE HIGHER VALLEYS COULD SEE SNOW AS WELL. TOO
EARLY TO SAY HOW MUCH ACCUMULATION COULD DEVELOP...BUT AN INCH OR
TWO IS POSSIBLE. THE WINDS WILL CONTINUE TO INCREASE ACROSS THE
CWFA...ESPECIALLY DURING THE DAY MONDAY WITH MIXING. GUSTS UP TO 45
MPH ARE POSSIBLE OVER THE MTNS...WITH 40 MPH ELSEWHERE. LOWS WILL BE
AROUND 5 DEGREES BELOW NORMAL WITH FREEZING TEMPS LIKELY ABOVE 3500
FT. HIGHS MONDAY 10 TO 15 DEGREES BELOW NORMAL.
LOW LEVEL MOISTURE BRIEFLY WANES MON NITE THEN RETURNS ACROSS THE TN
BORDER COUNTIES TUE. EXPECT RAIN/SNOW SHOWERS TO DIMINISH MON EVE
THEN RETURN FOR THE DAY TUE. WINDS DROP OFF A LITTLE MON NITE BUT
REMAIN BREEZY...THEN RETURN EVEN STRONGER ON TUE. TUE LOOKS TO BE
THE WINDIEST DAY WITH GUSTS LIKELY REACHING WIND ADV LEVELS OVER THE
MTNS WITH HIGH WIND WARNING GUSTS POSSIBLE. GUSTS COULD REACH 40 TO
45 MPH ELSEWHERE. WIDESPREAD FREEZE OVER THE MTNS STILL EXPECTED MON
NITE WITH LOW TO MID 30S ELSEWHERE...WITH FREEZE POSSIBLE INTO THE
NC FOOTHILLS. HIGHS TUE 15 TO 20 DEGREES BELOW NORMAL.
&&
.LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/...
AS OF 2 PM FRIDAY...THE EXTENDED RANGE WILL FEATURE A SLOW
DIMINISHMENT OF THE LINGERING EFFECTS OF TC SANDY/S REMNANTS.
EXTENDED RANGE MODEL PROGS AND GUIDANCE DEPICT A LINGERING TIGHT
PRESSURE GRADIENT/DEEP CYCLONIC FLOW ATOP THE SE CONUS ON WEDNESDAY.
BASED ON THIS PATTERN ONE CAN INFER THAT THE MAIN SENSIBLE WX FOR
THE CWFA WILL FEATURE GUSTY WESTERLY WINDS AND COOL TEMPERATURES.
ALTHOUGH MAX TEMPS WILL MODERATE SOME FROM TUESDAY/S CHILLY
READINGS...VALUES ARE STILL PROGGED TO BE 12-15 DEG F BELOW CLIMO.
AT LEAST BREEZY CONDITIONS ARE LIKELY TO DEVELOP AGAIN ON THURSDAY
WITHIN THE LINGERING CYCLONIC FLOW...BUT MAX TEMPS WILL MAKE AN
UPWARD JOG...RISING ABOUT 3-5 DEG F ABOVE PERSISTENCE. BROAD CENTRAL
CONUS RIDING WILL SLOWLY NOSE EASTWARD ON FRIDAY AND MAX TEMPS WILL
MAKE AN ADDITIONAL 1-2 DEG F UPWARD JOG...BUT STILL REMAIN AT LEAST
TWO CATEGORIES BELOW CLIMO.
&&
.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
AT KCLT...LATEST MODEL GUIDANCE SHOWS MOISTENING BOUNDARY LAYER LATE
TONIGHT WHICH WOULD CONTINUE TO SUPPORT MVFR CIGS DEVELOPING LATE
TONIGHT. A LITTLE MORE CONFIDENT THAT THEY WILL FORM AND WITH THE
LAYER NEAR SATURATION LOWERED THE CIG SOMEWHAT. THE MOISTURE LINGERS
THROUGH SATURDAY MORNING WITH MOIST UPSLOPE FLOW CONTINUING IN THE
MIDLEVELS WHICH WILL BRING IN CLOUDS OF ITS OWN...AND CIRRUS BANDS
WILL STILL BE OVERHEAD GIVEN THE PROXIMITY OF SANDY. PUTTING THIS
TOGETHER I DON/T SEE THE STRATUS LIFTING RAPIDLY AND THINK THAT THE
MVFR CIG WILL CONTINUE UNTIL MIDDAY. ISOLATED SHOWERS ARE STILL
EXPECTED OVER THE PIEDMONT FROM THE LATE OVERNIGHT HOURS INTO
TOMORROW BUT WITH THE EXPECTED LOW COVERAGE WILL NOT MENTION IN TAF
ATTM. WINDS SHOULD EASILY GUST IN THE 15 TO 18 KT RANGE.
ELSEWHERE...SCATTERED VFR STRATOCUMULUS WILL PERSIST THROUGH THE
EVENING IN THE MOUNTAINS WITH OTHER LOCATIONS MAINLY JUST SEEING
CIRRUS FROM HURRICANE SANDY. CLOUDS SHOULD INCREASE OVER THE WEST AS
SFC COLD FRONT MOVES IN LATER TONIGHT...AND OVER THE EAST AS
ATLANTIC MOISTURE CONTINUES MOVING IN. CIGS UPSTREAM ARE CURRENTLY
VFR BUT BOUNDARY LAYER MOISTURE INCREASES OVERNIGHT SO CIGS WILL
EVENTUALLY LOWER TO MVFR WITH SOME MOUNTAIN SITES SEEING IFR IN
ADDITION TO IFR FOG. PRECIP CHANCES WERE LOWERED FOR THE OVERNIGHT
HOURS IN LIGHT OF LACK OF ACTIVITY UPSTREAM THOUGH A FEW SHOWERS ARE
NOT OUT OF THE QUESTION. ANY SHOWERS THAT DO FORM SHOULD BE LIGHT
AND HAVE LITTLE OPERATIONAL IMPACT. CIGS WILL LIFT THROUGH THE
MORNING...BUT SLOWLY AS HIGHER CLOUD LAYERS OVERLAYING THE STRATUS
WIL INHIBIT DISSIPATION. GUSTY WINDS TOMORROW AFTERNOON IN THE 15 TO
20 KT RANGE.
OUTLOOK...LOW LEVEL MOISTURE SHOULD GENERATE RESTRICTIVE CIGS AGAIN
INTO SUNDAY. A VIGOROUS PUSH OF COLD AIR BEHIND HURRICANE SANDY WILL
ARRIVE EARLY NEXT WEEK...CREATING VERY WINDY CONDITIONS ACROSS THE
REGION...AND POSSIBLE MOUNTAIN CEILING RESTRICTIONS IN THE NW FLOW.
AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)...
WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...CSH
NEAR TERM...WIMBERLEY
SHORT TERM...RWH
LONG TERM...CSH
AVIATION...WIMBERLEY
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
1103 PM CDT FRI OCT 26 2012
.DISCUSSION.../ISSUED AT 925 PM CDT/
AFTER A DAY AND A HALF OR TWO OF DEALING WITH THIS THIN SATURATED
LAYER AND CLOUDS...IT IS APPARENT THAT THE CLEARING TREND IS FINALLY
HERE FOR REAL FOR THE REST OF TONIGHT. CURRENT CLEARING OF LOW
CLOUDS TO WESTERN EDGE OF FORECAST AREA AND HOLES IN THE MIDDLE SEEM
TO CONFIRM THE DECENT SUBSIDENCE NEW NAM/NAM12 IS SHOWING WITH
SURFACE RIDGE. WILL NOT TAKE IT COMPLETELY CLEAR BECAUSE OF POSSIBLE
LINGERING THIN MOIST PATCHES AS WELL AS SOME MID AND HIGH CLOUDS
APPROACHING FROM THE WEST BUT IT COULD BECOME A PRETTY STARRY NIGHT
EVENTUALLY. WEAK SATURDAY/SATURDAY NIGHT SYSTEM STILL THERE ON NEW
NAM SO NO CHANGES IN LIGHT PRECIPITATION OUTLOOK WITH STILL MORE
GUIDANCE TO COME ON THAT. HOURLY TEMPERATURES HAVE NEEDED ADJUSTING
BUT THE PENDING CLEARING IS MAKING THE EARLIER FORECAST
LOWS...MOSTLY LOWER 20S...LOOK GOOD.
&&
.AVIATION.../FOR THE 06Z TAF ISSUANCE/
CLEARING OF LOW CLOUDS NOW SEEMS ON TRACK TO PROGRESS EAST ACROSS
THE CWA DURING THE EARLY HOURS OF THE TAF PERIOD. VFR CONDITIONS ARE
THEN EXPECTED THROUGH LATE SATURDAY AFTERNOON...THOUGH MID LEVEL
CLOUDS WILL ADVANCE INTO THE AREA AHEAD OF APPROACHING UPPER LEVEL
WAVE. THIS WAVE EXPECTED TO PRODUCE AREAS LIGHT RAIN/LIGHT SNOW INTO
AREAS WEST OF INTERSTATE 29 AFTER 21Z...WITH CHANCE THEN EXPANDING
EASTWARD INTO SOUTHWEST MINNESOTA BY 28/06Z. PERIOD OF MVFR CEILINGS
AND/OR VISIBILITY POSSIBLE WITH THE PRECIPITATION.
&&
.PREV DISCUSSION.../ISSUED AT 333 PM CDT/
BIGGEST CHALLENGE TONIGHT WILL AGAIN BE WHEN/IF STRATUS DISSIPATES
ACROSS THE AREA. PER LATEST SATELLITE IMAGE...PRESENTLY SEEING THE
ENTIRE CWA SOCKED IN WITH CLOUDS...WITH SOME BREAKS OVER NORTH
CENTRAL AND NORTHEASTERN SOUTH DAKOTA. MODELS STILL NOT HANDLING THE
LOW LEVEL RH FIELDS VERY WELL...ALTHOUGH THE RAP SEEMS TO HAVE BEEN
DOING THE BEST SINCE YESTERDAY AFTERNOON. IN LIGHT OF THAT...WENT
WITH THAT MODEL FOR LOW LEVEL CLOUDS THIS EVENING...WITH THEM
BEGINNING TO BREAK UP BY 06Z TONIGHT. THE CLOUD COVER WILL HAVE A
BIG IMPACT ON LOW TEMPERATURES...AND WITH WINDS GOING LIGHT AS A
SURFACE RIDGE SLIDES OVERHEAD...ANY CLEARING WILL ALLOW READINGS TO
DROP DOWN INTO THE LOWER 20S NORTH AND EAST. IT WILL REMAIN A LITTLE
WARMER IN THE SOUTHWEST HOWEVER...WITH MID AND HIGH CLOUDS EXPECTED
TO STREAM INTO THAT AREA LATER IN THE NIGHT OUT AHEAD OF THE NEXT
SYSTEM. HOWEVER...IF CLOUDS REMAIN THROUGHOUT MOST OF THE AREA
TONIGHT...LOWS WILL BE WARMER THAN CURRENTLY FORECASTED AND THE
EVENING SHIFT MAY HAVE TO UPDATE.
ON SATURDAY...CLOUDS WILL INCREASE ACROSS THE AREA EARLY IN THE
DAY...ASSUMING WE EVEN GET ANY CLEARING TONIGHT...AS A SHORTWAVE
APPROACHES FROM THE WEST BY AFTERNOON. DOES APPEAR NOW THAT MUCH OF
ANY PRECIPITATION THAT DEVELOPS WITH THE SYSTEM WILL HOLD OFF UNTIL
LATER AFTERNOON. WHILE PROGGED 850 MB TEMPS ARE PROGGED TO BE BELOW
0 C...BUFKIT SOUNDINGS SHOW A WARMER LAYER FROM AROUND 900 MB TO THE
SURFACE...AND THINK THAT EVEN COOLING TO WET BULB WILL KEEP A
RAIN/SNOW MIX IN THE AFTERNOON IF PRECIPITATION DEVELOPS. WITH
WARMING 925 MB TEMPERATURE PROFILES...HIGHS WILL BE A LITTLE WARMER
ON SATURDAY...THOUGH STILL WELL BELOW NORMAL FOR THIS TIME OF
YEAR...IN THE LOWER 40S NORTH TO MID/UPPER 40S FAR SOUTH.
SHORT WAVE TROUGH IS EXPECTED TO TRACK INTO THE EASTERN HALF OF THE
FORECAST AREA SATURDAY NIGHT WHILE THE WEAK INVERTED SURFACE TROUGH
LIFTS NORTH NORTHEAST INTO SOUTHERN MINNESOTA BY DAYBREAK SUNDAY.
LIGHT PRECIPITATION WILL BE LIKELY AS IT SPREADS EAST INTO OUR
WESTERN CWA IN THE EVENING. WITH TEMPERATURES DROPPING NEAR FREEZING
AROUND SUNSET...LIGHT RAIN AND SNOW WILL TRANSITION TO SNOW AND
BECOME SCATTERED AFTER MIDNIGHT AS THE INVERTED TROUGH LIFTS
NORTHEASTWARD AND ENCOUNTERS DRIER LOWER LEVELS. SNOWFALL AMOUNTS
WILL BE AROUND A HALF IN OR LESS FOR MOST AREAS...WITH POTENTIALLY
UP TO AN INCH IN EAST CENTRAL SOUTH DAKOTA AND LITTLE TO NO
ACCUMULATION IN NORTHWEST IOWA.
MODELS INDICATE THAT THE STRATUS COULD LINGER ACROSS THE AREA INTO
SUNDAY...PARTICULARLY IN THE EASTERN HALF WHERE MODELS HINT AT SOME
LINGERING FLURRIES NEAR OUR FAR EASTERN BORDER COULD STICK AROUND
INTO MID MORNING. CLOUDS MAY BE HARD TO CLEAR EVEN IN THE
AFTERNOON...SO HAVE LEFT MOSTLY OR PARTLY CLOUDY SKIES. HIGHS WILL
BE IN THE 40S. LOWS ON SUNDAY NIGHT WILL BE LARGELY DEPENDENT ON
WHETHER WE HOLD ONTO THE CLOUDS...BUT WITH SOME CLOUD COVERAGE
EXPECTED...WILL GO WITH SOME MIDDLE GROUND LOWS NEAR OR JUST BELOW
FREEZING.
FOR THE EXTENDED...IT LOOKS LIKE LARGE SCALE NORTHWEST FLOW WILL BE
LOCKED IN PLACE THROUGH MID TO LATE WEEK ACROSS THE NORTHERN AND
CENTRAL PLAINS AS HURRICANE SANDY HEADS INTO THE MID ATLANTIC AND
NEW ENGLAND STATES. TEMPERATURES WILL BE ON A VERY SLOW WARMING
TREND THROUGH THE PERIOD WITH THE RIDGE AXIS TO OUR WEST GRADUALLY
SHIFTING INTO THE PLAINS. MODELS STILL NOT IN TOTAL AGREEMENT WITH
THE TRACK OF SANDY...BUT FOR OUR NECK OF THE WOODS...THESE
DISCREPANCIES ONLY RESULT IN SOME SLIGHT WIND AND TEMPERATURE
DIFFERENCES. DID BUMP UP TEMPERATURES A FEW DEGREES FROM ALLBLEND
FOR WEDNESDAY THROUGH FRIDAY. THE OVERALL PATTERN STILL LOOKS DRY
INTO FRIDAY.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
925 PM CDT FRI OCT 26 2012
.DISCUSSION.../ISSUED AT 925 PM CDT/
AFTER A DAY AND A HALF OR TWO OF DEALING WITH THIS THIN SATURATED
LAYER AND CLOUDS...IT IS APPARENT THAT THE CLEARING TREND IS FINALLY
HERE FOR REAL FOR THE REST OF TONIGHT. CURRENT CLEARING OF LOW
CLOUDS TO WESTERN EDGE OF FORECAST AREA AND HOLES IN THE MIDDLE SEEM
TO CONFIRM THE DECENT SUBSIDENCE NEW NAM/NAM12 IS SHOWING WITH
SURFACE RIDGE. WILL NOT TAKE IT COMPLETELY CLEAR BECAUSE OF POSSIBLE
LINGERING THIN MOIST PATCHES AS WELL AS SOME MID AND HIGH CLOUDS
APPROACHING FROM THE WEST BUT IT COULD BECOME A PRETTY STARRY NIGHT
EVENTUALLY. WEAK SATURDAY/SATURDAY NIGHT SYSTEM STILL THERE ON NEW
NAM SO NO CHANGES IN LIGHT PRECIPITATION OUTLOOK WITH STILL MORE
GUIDANCE TO COME ON THAT. HOURLY TEMPERATURES HAVE NEEDED ADJUSTING
BUT THE PENDING CLEARING IS MAKING THE EARLIER FORECAST
LOWS...MOSTLY LOWER 20S...LOOK GOOD.
&&
.AVIATION.../FOR THE 00Z TAF ISSUANCE/
VFR STRATUS DECK PERSISTS ACROSS THE AREA AT THE START OF THE TAF
PERIOD...ALTHOUGH STARTING TO SEE POCKETS OF DRYING/CLEARING WORK
EASTWARD ACROSS WESTERN/CENTRAL SD AS SURFACE RIDGE AXIS MOVES EAST.
CONFIDENCE IS LOW WITH REGARD TO WHETHER CEILINGS WILL BREAK UP
TONIGHT...AS LARGE SCALE MODELS HAVE HAD POOR HANDLE ON THIS LOW
LEVEL RELATIVE HUMIDITY. HOWEVER HIGHER RESOLUTION MODELS ALSO NOW
PROGRESSING THE PARTIAL CLEARING EASTWARD AND WILL TREND TOWARD
3-4KFT CLOUDS BECOMING SCATTERED FROM NORTHWEST TO SOUTHEAST AFTER
06Z. EXPECT THIS LAYER TO EXPAND AGAIN BY LATE IN THE PERIOD ACROSS
THE WESTERN FORECAST AREA...WITH INCREASING MID LEVEL CLOUDS OVER
REMAINDER OF THE AREA...AS UPPER WAVE BEGINS TO SWING THROUGH THE
REGION. POTENTIAL FOR LIGHT RAIN OR SNOW TO DEVELOP INTO NORTHWEST
1/3 OF THE FORECAST AREA LATE IN THIS TAF PERIOD AND HAVE INCLUDED A
MENTION OF MVFR POTENTIAL IN KHON AFTER 27/21Z.
&&
.PREV DISCUSSION.../ISSUED AT 333 PM CDT/
BIGGEST CHALLENGE TONIGHT WILL AGAIN BE WHEN/IF STRATUS DISSIPATES
ACROSS THE AREA. PER LATEST SATELLITE IMAGE...PRESENTLY SEEING THE
ENTIRE CWA SOCKED IN WITH CLOUDS...WITH SOME BREAKS OVER NORTH
CENTRAL AND NORTHEASTERN SOUTH DAKOTA. MODELS STILL NOT HANDLING THE
LOW LEVEL RH FIELDS VERY WELL...ALTHOUGH THE RAP SEEMS TO HAVE BEEN
DOING THE BEST SINCE YESTERDAY AFTERNOON. IN LIGHT OF THAT...WENT
WITH THAT MODEL FOR LOW LEVEL CLOUDS THIS EVENING...WITH THEM
BEGINNING TO BREAK UP BY 06Z TONIGHT. THE CLOUD COVER WILL HAVE A
BIG IMPACT ON LOW TEMPERATURES...AND WITH WINDS GOING LIGHT AS A
SURFACE RIDGE SLIDES OVERHEAD...ANY CLEARING WILL ALLOW READINGS TO
DROP DOWN INTO THE LOWER 20S NORTH AND EAST. IT WILL REMAIN A LITTLE
WARMER IN THE SOUTHWEST HOWEVER...WITH MID AND HIGH CLOUDS EXPECTED
TO STREAM INTO THAT AREA LATER IN THE NIGHT OUT AHEAD OF THE NEXT
SYSTEM. HOWEVER...IF CLOUDS REMAIN THROUGHOUT MOST OF THE AREA
TONIGHT...LOWS WILL BE WARMER THAN CURRENTLY FORECASTED AND THE
EVENING SHIFT MAY HAVE TO UPDATE.
ON SATURDAY...CLOUDS WILL INCREASE ACROSS THE AREA EARLY IN THE
DAY...ASSUMING WE EVEN GET ANY CLEARING TONIGHT...AS A SHORTWAVE
APPROACHES FROM THE WEST BY AFTERNOON. DOES APPEAR NOW THAT MUCH OF
ANY PRECIPITATION THAT DEVELOPS WITH THE SYSTEM WILL HOLD OFF UNTIL
LATER AFTERNOON. WHILE PROGGED 850 MB TEMPS ARE PROGGED TO BE BELOW
0 C...BUFKIT SOUNDINGS SHOW A WARMER LAYER FROM AROUND 900 MB TO THE
SURFACE...AND THINK THAT EVEN COOLING TO WET BULB WILL KEEP A
RAIN/SNOW MIX IN THE AFTERNOON IF PRECIPITATION DEVELOPS. WITH
WARMING 925 MB TEMPERATURE PROFILES...HIGHS WILL BE A LITTLE WARMER
ON SATURDAY...THOUGH STILL WELL BELOW NORMAL FOR THIS TIME OF
YEAR...IN THE LOWER 40S NORTH TO MID/UPPER 40S FAR SOUTH.
SHORT WAVE TROUGH IS EXPECTED TO TRACK INTO THE EASTERN HALF OF THE
FORECAST AREA SATURDAY NIGHT WHILE THE WEAK INVERTED SURFACE TROUGH
LIFTS NORTH NORTHEAST INTO SOUTHERN MINNESOTA BY DAYBREAK SUNDAY.
LIGHT PRECIPITATION WILL BE LIKELY AS IT SPREADS EAST INTO OUR
WESTERN CWA IN THE EVENING. WITH TEMPERATURES DROPPING NEAR FREEZING
AROUND SUNSET...LIGHT RAIN AND SNOW WILL TRANSITION TO SNOW AND
BECOME SCATTERED AFTER MIDNIGHT AS THE INVERTED TROUGH LIFTS
NORTHEASTWARD AND ENCOUNTERS DRIER LOWER LEVELS. SNOWFALL AMOUNTS
WILL BE AROUND A HALF IN OR LESS FOR MOST AREAS...WITH POTENTIALLY
UP TO AN INCH IN EAST CENTRAL SOUTH DAKOTA AND LITTLE TO NO
ACCUMULATION IN NORTHWEST IOWA.
MODELS INDICATE THAT THE STRATUS COULD LINGER ACROSS THE AREA INTO
SUNDAY...PARTICULARLY IN THE EASTERN HALF WHERE MODELS HINT AT SOME
LINGERING FLURRIES NEAR OUR FAR EASTERN BORDER COULD STICK AROUND
INTO MID MORNING. CLOUDS MAY BE HARD TO CLEAR EVEN IN THE
AFTERNOON...SO HAVE LEFT MOSTLY OR PARTLY CLOUDY SKIES. HIGHS WILL
BE IN THE 40S. LOWS ON SUNDAY NIGHT WILL BE LARGELY DEPENDENT ON
WHETHER WE HOLD ONTO THE CLOUDS...BUT WITH SOME CLOUD COVERAGE
EXPECTED...WILL GO WITH SOME MIDDLE GROUND LOWS NEAR OR JUST BELOW
FREEZING.
FOR THE EXTENDED...IT LOOKS LIKE LARGE SCALE NORTHWEST FLOW WILL BE
LOCKED IN PLACE THROUGH MID TO LATE WEEK ACROSS THE NORTHERN AND
CENTRAL PLAINS AS HURRICANE SANDY HEADS INTO THE MID ATLANTIC AND
NEW ENGLAND STATES. TEMPERATURES WILL BE ON A VERY SLOW WARMING
TREND THROUGH THE PERIOD WITH THE RIDGE AXIS TO OUR WEST GRADUALLY
SHIFTING INTO THE PLAINS. MODELS STILL NOT IN TOTAL AGREEMENT WITH
THE TRACK OF SANDY...BUT FOR OUR NECK OF THE WOODS...THESE
DISCREPANCIES ONLY RESULT IN SOME SLIGHT WIND AND TEMPERATURE
DIFFERENCES. DID BUMP UP TEMPERATURES A FEW DEGREES FROM ALLBLEND
FOR WEDNESDAY THROUGH FRIDAY. THE OVERALL PATTERN STILL LOOKS DRY
INTO FRIDAY.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
625 PM CDT FRI OCT 26 2012
.DISCUSSION.../ISSUED AT 333 PM CDT/
BIGGEST CHALLENGE TONIGHT WILL AGAIN BE WHEN/IF STRATUS DISSIPATES
ACROSS THE AREA. PER LATEST SATELLITE IMAGE...PRESENTLY SEEING THE
ENTIRE CWA SOCKED IN WITH CLOUDS...WITH SOME BREAKS OVER NORTH
CENTRAL AND NORTHEASTERN SOUTH DAKOTA. MODELS STILL NOT HANDLING THE
LOW LEVEL RH FIELDS VERY WELL...ALTHOUGH THE RAP SEEMS TO HAVE BEEN
DOING THE BEST SINCE YESTERDAY AFTERNOON. IN LIGHT OF THAT...WENT
WITH THAT MODEL FOR LOW LEVEL CLOUDS THIS EVENING...WITH THEM
BEGINNING TO BREAK UP BY 06Z TONIGHT. THE CLOUD COVER WILL HAVE A
BIG IMPACT ON LOW TEMPERATURES...AND WITH WINDS GOING LIGHT AS A
SURFACE RIDGE SLIDES OVERHEAD...ANY CLEARING WILL ALLOW READINGS TO
DROP DOWN INTO THE LOWER 20S NORTH AND EAST. IT WILL REMAIN A LITTLE
WARMER IN THE SOUTHWEST HOWEVER...WITH MID AND HIGH CLOUDS EXPECTED
TO STREAM INTO THAT AREA LATER IN THE NIGHT OUT AHEAD OF THE NEXT
SYSTEM. HOWEVER...IF CLOUDS REMAIN THROUGHOUT MOST OF THE AREA
TONIGHT...LOWS WILL BE WARMER THAN CURRENTLY FORECASTED AND THE
EVENING SHIFT MAY HAVE TO UPDATE.
ON SATURDAY...CLOUDS WILL INCREASE ACROSS THE AREA EARLY IN THE
DAY...ASSUMING WE EVEN GET ANY CLEARING TONIGHT...AS A SHORTWAVE
APPROACHES FROM THE WEST BY AFTERNOON. DOES APPEAR NOW THAT MUCH OF
ANY PRECIPITATION THAT DEVELOPS WITH THE SYSTEM WILL HOLD OFF UNTIL
LATER AFTERNOON. WHILE PROGGED 850 MB TEMPS ARE PROGGED TO BE BELOW
0 C...BUFKIT SOUNDINGS SHOW A WARMER LAYER FROM AROUND 900 MB TO THE
SURFACE...AND THINK THAT EVEN COOLING TO WET BULB WILL KEEP A
RAIN/SNOW MIX IN THE AFTERNOON IF PRECIPITATION DEVELOPS. WITH
WARMING 925 MB TEMPERATURE PROFILES...HIGHS WILL BE A LITTLE WARMER
ON SATURDAY...THOUGH STILL WELL BELOW NORMAL FOR THIS TIME OF
YEAR...IN THE LOWER 40S NORTH TO MID/UPPER 40S FAR SOUTH.
SHORT WAVE TROUGH IS EXPECTED TO TRACK INTO THE EASTERN HALF OF THE
FORECAST AREA SATURDAY NIGHT WHILE THE WEAK INVERTED SURFACE TROUGH
LIFTS NORTH NORTHEAST INTO SOUTHERN MINNESOTA BY DAYBREAK SUNDAY.
LIGHT PRECIPITATION WILL BE LIKELY AS IT SPREADS EAST INTO OUR
WESTERN CWA IN THE EVENING. WITH TEMPERATURES DROPPING NEAR FREEZING
AROUND SUNSET...LIGHT RAIN AND SNOW WILL TRANSITION TO SNOW AND
BECOME SCATTERED AFTER MIDNIGHT AS THE INVERTED TROUGH LIFTS
NORTHEASTWARD AND ENCOUNTERS DRIER LOWER LEVELS. SNOWFALL AMOUNTS
WILL BE AROUND A HALF IN OR LESS FOR MOST AREAS...WITH POTENTIALLY
UP TO AN INCH IN EAST CENTRAL SOUTH DAKOTA AND LITTLE TO NO
ACCUMULATION IN NORTHWEST IOWA.
MODELS INDICATE THAT THE STRATUS COULD LINGER ACROSS THE AREA INTO
SUNDAY...PARTICULARLY IN THE EASTERN HALF WHERE MODELS HINT AT SOME
LINGERING FLURRIES NEAR OUR FAR EASTERN BORDER COULD STICK AROUND
INTO MID MORNING. CLOUDS MAY BE HARD TO CLEAR EVEN IN THE
AFTERNOON...SO HAVE LEFT MOSTLY OR PARTLY CLOUDY SKIES. HIGHS WILL
BE IN THE 40S. LOWS ON SUNDAY NIGHT WILL BE LARGELY DEPENDENT ON
WHETHER WE HOLD ONTO THE CLOUDS...BUT WITH SOME CLOUD COVERAGE
EXPECTED...WILL GO WITH SOME MIDDLE GROUND LOWS NEAR OR JUST BELOW
FREEZING.
FOR THE EXTENDED...IT LOOKS LIKE LARGE SCALE NORTHWEST FLOW WILL BE
LOCKED IN PLACE THROUGH MID TO LATE WEEK ACROSS THE NORTHERN AND
CENTRAL PLAINS AS HURRICANE SANDY HEADS INTO THE MID ATLANTIC AND
NEW ENGLAND STATES. TEMPERATURES WILL BE ON A VERY SLOW WARMING
TREND THROUGH THE PERIOD WITH THE RIDGE AXIS TO OUR WEST GRADUALLY
SHIFTING INTO THE PLAINS. MODELS STILL NOT IN TOTAL AGREEMENT WITH
THE TRACK OF SANDY...BUT FOR OUR NECK OF THE WOODS...THESE
DISCREPANCIES ONLY RESULT IN SOME SLIGHT WIND AND TEMPERATURE
DIFFERENCES. DID BUMP UP TEMPERATURES A FEW DEGREES FROM ALLBLEND
FOR WEDNESDAY THROUGH FRIDAY. THE OVERALL PATTERN STILL LOOKS DRY
INTO FRIDAY.
&&
.AVIATION.../FOR THE 00Z TAF ISSUANCE/
VFR STRATUS DECK PERSISTS ACROSS THE AREA AT THE START OF THE TAF
PERIOD...ALTHOUGH STARTING TO SEE POCKETS OF DRYING/CLEARING WORK
EASTWARD ACROSS WESTERN/CENTRAL SD AS SURFACE RIDGE AXIS MOVES EAST.
CONFIDENCE IS LOW WITH REGARD TO WHETHER CEILINGS WILL BREAK UP
TONIGHT...AS LARGE SCALE MODELS HAVE HAD POOR HANDLE ON THIS LOW
LEVEL RELATIVE HUMIDITY. HOWEVER HIGHER RESOLUTION MODELS ALSO NOW
PROGRESSING THE PARTIAL CLEARING EASTWARD AND WILL TREND TOWARD
3-4KFT CLOUDS BECOMING SCATTERED FROM NORTHWEST TO SOUTHEAST AFTER
06Z. EXPECT THIS LAYER TO EXPAND AGAIN BY LATE IN THE PERIOD ACROSS
THE WESTERN FORECAST AREA...WITH INCREASING MID LEVEL CLOUDS OVER
REMAINDER OF THE AREA...AS UPPER WAVE BEGINS TO SWING THROUGH THE
REGION. POTENTIAL FOR LIGHT RAIN OR SNOW TO DEVELOP INTO NORTHWEST
1/3 OF THE FORECAST AREA LATE IN THIS TAF PERIOD AND HAVE INCLUDED A
MENTION OF MVFR POTENTIAL IN KHON AFTER 27/21Z.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
257 PM CDT THU OCT 25 2012
.DISCUSSION.../ISSUED AT 257 PM CDT/
PRECIPITATION HAS ENDED ACROSS THE ENTIRE CWA LATE THIS
AFTERNOON...LEAVING BEHIND A BROAD AREA OF STRATUS OVER THE REGION.
THESE CLOUDS WILL BE THE MAIN CHALLENGE FOR THE SHORTER TERM
PERIOD...WITH MODELS NOT HANDLING THE LOW CLOUDS WELL. RUC LOOKS TO
BE THE BEST WITH THE LOW LEVEL RH FIELD...AND KEEPS THE STRATUS OVER
OUR AREA THROUGH AT LEAST THE EARLY EVENING. AS HIGH PRESSURE BUILDS
INTO THE REGION FROM THE WEST OVERNIGHT...A LESSENING SURFACE
GRADIENT WILL ALLOW WINDS TO COME DOWN BY EARLY EVENING. WENT ON THE
LOW SIDE OF GUIDANCE WITH REGARD TO LOWS TONIGHT...GENERALLY UPPER
TEENS TO LOWER 20S...WITH RELATIVELY LIGHT WINDS...SOME POSSIBLE
SNOW COVER IN SOME AREAS...AND BANKING ON CLOUDS BEGINNING TO BREAK
UP OVERNIGHT. IF CLOUDS PERSIST...IT MAY NOT GET AS COLD AS
CURRENTLY IN THE FORECAST. ANOTHER CHALLENGE WILL BE WHETHER ANY FOG
IS ABLE TO DEVELOP TOWARD FRIDAY MORNING. WHILE NOT AN IDEAL SET UP
WITH LIGHT NORTHWESTERLY WINDS...THINKING IS IF CLOUDS CLEAR OUT AND
WINDS DROP OFF...IN CONJUNCTION WITH ABUNDANT NEAR SURFACE MOISTURE
FROM RECENT RAINFALL/SNOW MELT...FOG WILL DEVELOP IN SOME AREAS. DID
NOT INCLUDE IN THE FORECAST AT THIS POINT...HOWEVER EVENING SHIFT
MAY UPDATE IF IT LOOKS MORE LIKELY.
FRIDAY LOOKS TO BE ANOTHER COOL DAY WITH THE CENTER OF THE HIGH
PRESSURE SLIDING OVERHEAD BY AFTERNOON. THERMAL PROFILES ACTUALLY
COOL A BIT OVER TODAY...THOUGH MODELS HINT AT SOME MID CLOUDS
STREAMING INTO OUR WEST...THERE WILL GENERALLY BE MORE SUN THAN
TODAY WITH HIGHS REACHING INTO UPPER 30S TO LOWER 40S. /JM
FRIDAY NIGHT WILL SEE A WEAK RIDGE OF HIGH PRESSURE MOVE ACROSS THE
AREA...LOCATED NEAR NORTHWEST IOWA BY 12Z SATURDAY. TO THE WEST
SOUTHERLY FLOW AS WELL AS CLOUD COVER WILL INCREASE AS A SHORTWAVE
MOVES INTO THE NORTHERN AND CENTRAL ROCKIES. THIS WILL MAKE FOR
TRICKY LOW TEMPERATURES FORECASTING. WILL LEAN A LITTLE MORE TOWARD
THE CONSMOS IN NORTHWEST IA WHERE WINDS WILL BE LIGHTEST AND CLOSER
TO THE CONSRAW IN CENTRAL SD WHERE WINDS AND CLOUDS WILL LIKELY KEEP
TEMPERATURES A LITTLE MILDER.
LATE SATURDAY AFTERNOON AND SATURDAY NIGHT WILL PROVE TO BE THE NEXT
CHANCE FOR PRECIPITATION. THERE ARE SOME DIFFERENCES AMONGST THE
MODELS LEADING TOWARDS LOWER CONFIDENCE IN A SOLUTION. THE GFS IS
THE MOST BOISTEROUS LEAVING COLDER AIR IN PLACE AND BRINGING HEAVIER
QPF AMOUNTS TO THE NORTHERN CWA. THE NAM IS MUCH WARMER IN THE LOWER
LEVELS THAN THE GFS WHILE THE ECMWF IS A LITTLE BIT WARMER. BOTH
MODELS WOULD LIKELY SUPPORT SNOW HOWEVER AS THE LOW LEVELS ARE
FAIRLY DRY AND WOULD EASILY SWITCH TO SNOW. SREF SOUNDINGS ALL OVER
THE PLACE DURING THIS TIME FRAME AS WELL. DYNAMICALLY THERE IS
SUPPORT FOR SOME PRECIPITATION WITH ICE PROCESSES LIKELY AS THE -12
TO -18 DEGREE C LAYER IS FROM ABOUT 9000 TO 15000 FEET AND THERE
WOULD LIKELY BE A LITTLE BIT OF FRONTAL FORCING AROUND THIS LAYER.
HOWEVER...FRONTAL FORCING WEAK AND WAVE NOT VERY WELL DEFINED SO
BELIEVE THAT THE NAM AND GFS OVERDOING QPF AMOUNTS IN THE THIRD TO
HALF AN INCH RANGE. THE MUCH STRONGER AND BETTER DEFINED SYSTEM THAT
JUST MOVED THROUGH TODAY BARELY PRODUCED AMOUNTS THIS HIGH SO WILL
LOWER BY ABOUT TWO THIRDS. WILL INCREASE POPS INTO THE LIKELY
CATEGORY SATURDAY NIGHT ALONG THE HIGHWAY 14 CORRIDOR HOWEVER AS
SOME MEASURABLE SNOWFALL LOOKS POSSIBLE. WILL KEEP HIGHS THE COOLEST
OVER THE NORTHERN CWA WHERE A MIX OF POTENTIALLY THICKER CLOUD COVER
AND COOLER LOW LEVEL THERMAL FIELD WHILE THE SOUTH COULD MIX JUST A
BIT WITH A SOUTHERLY COMPONENT. LOOKING AT LOWER 40S NORTH TO NEAR
50 SOUTH.
MOST OF THE SNOWFALL WILL BE EAST OF THE AREA ON SUNDAY MORNING WITH
GRADUALLY CLEARING SKIES THROUGH THE DAY. WINDS WILL NOT BE VERY
STRONG SO COOL HIGH TEMPERATURES IN THE MID 40S TO AROUND 50 WILL
NOT FEEL TOO BAD.
IN THE LATTER PERIODS(MON/THU)...NOT MUCH CHANGE IN THIS PERIOD AS
MODELS CONTINUE TO CONVERGE ON THE ECMWF SOLUTION. WHICH HAS BEEN
VERY CONSISTENT THIS WEEK. BASICALLY LOOKING AT A RIDGE OF HIGH
PRESSURE AT THE SURFACE VARYING FROM ABOUT THE BIG SIOUX RIVER
VALLEY EAST INTO WESTERN MINNESOTA. THIS WILL KEEP COOL CONDITIONS
IN PLACE BUT WINDS WILL LIKELY REMAIN FAIRLY CALM. THE WESTERN CWA
WILL SEE THE BEST CHANCE FOR ABOVE NORMAL TEMPERATURES WHILE
SOUTHWEST MINNESOTA WILL HAVE THE BEST CHANCE AT NORMAL TO A BIT
BELOW NORMAL TEMPERATURES. /08
&&
.AVIATION.../FOR THE 18Z TAF ISSUANCE/
WITH MODEL DIFFERENCES...CONFIDENCE RATHER LOW WITH REGARD TO HOW
QUICKLY STRATUS DEPARTS THE REGION...BUT THINK CLOUDS WILL BEGIN TO
LIFT A BIT BY LATE THIS AFTERNOON. BY TONIGHT...NORTHWESTERLY WINDS
WILL BECOME RELATIVELY LIGHT. DEPENDENT ON ANY REMAINING CLOUD COVER
AND HOW LIGHT WINDS BECOME OVERNIGHT...WILL BE THE POSSIBILITY OF
FOG FORMATION OVER PORTIONS OF THE AREA VERY LATE TONIGHT INTO
FRIDAY MORNING WITH ABUNDANT NEAR SURFACE MOISTURE WITH MELTING SNOW.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS SPOKANE WA
1052 PM PDT Wed Oct 24 2012
.SYNOPSIS...A band of rain and mountain snow will move through the
area today and tonight. The weather will generally be quiet on
Thursday before the next weather system arrives Friday with
additional storms for the weekend. More precipitation is expected
into early next week.
&&
.DISCUSSION...
Update to account for expiration of snow advisory in the
East Slopes. Western edge of the deformation band is weakening
with cloud tops quickly warming and HRRR all in good agreement
that additional QPF amounts will be 0.02" or less. As such, we
will allow the advisory to run its course and expire at 11PM.
Still be aware of slick driving conditions during the morning
hours due to re-freezing and/or any isolated light snow
accumulations from convective snow showers moving through
overnight.
Previous discussion: We have made some slight adjustments to
the winter weather advisory for the remainder of the night. A
band of light to moderate precipitation continues to impact the
northern mountains from the Pasayten Wilderness...eastward to the
Sandpoint, ID. Satellite reveals warming cloud tops suggesting
this band is weakening and is most concentrated over the Okanogan
Highlands...NE WA Mtns...and Nrn ID Panhandle.
A tour of observation networks across the region suggest snow levels
have dropped some with levels across the Okanogan Highlands, NE WA
Mtns, and Nrn ID Panhandle sitting around 3K ft. As such, we have
made adjustments to the winter wx advisory to bring light
acccumulations down to these levels. In IDZ004, the Central
Panhandle Mtns, pcpn is struggling to materialize and this will
equate to the lower snow totals. The NAM...EC...and HRRR have
captured this better then the GFS and were referenced for the
remainder of the night. Despite the lack of pcpn over this region
from the stable deformation band, cellular cloud structure in
conjuction with the model 500mb temperatures suggest the
atmosphere is going to become increasingly unstable once again.
Winds behind this evening`s wave should become SW/W before
swinging to the W/NW Thursday morning. In addition, another
midlevel circulation is currently crossing the Blue Mtns and
should incr the shower activity across lower Shoshone County
overnight. All it will take is a few heavy convective showers to
get going and localized accumulations of 1-3 inches will be
possible with the convective showers.
On another note, the lack of pcpn has allowed pockets of cooler
temperatures across the Idaho Panhandle with Wallace currently
sitting at 35F with a 32F dewpoint. Bonners Ferry is also 36F over
32F and as pcpn reaches into these locations, I would not be
surprised to see snow reach these valley floors. If the pcpn
remains light, the above freezing temperatures should neglect any
impacts but if any heavier showers were to come through, light
accumulations will be possible on roadways including I-90
between Wallace and 4th of July Pass.
All things considered, we have lowered the snow advisory for the
Central Panhandle Mtns down to 2500 feet. If the 00z GFS was to
verify...1-3 inches of snow will be easily achievable in locations
like Deary, Wallace, and Lookout Pass which has come in with
0.25" liquid along a elongated convergence zone or pressure
trough at the surface. /sb
&&
.AVIATION...
06Z TAFS: The steady band of rain and snow has pushed north of all
terminals however steepening lapse rates and smaller midlevel
disturbances will keep a threat for showers of rain and snow in the
fcst through early Thursday. Meanwhile, the BL remains very moist
with widespread stratus and fog expected throughout the Columbia
Basin...West Plains...and L-C Valley. All VIS/CIG restrictions
associated with low clouds and fog should lift btwn 18-21z and weak
high pressure aloft should promote a relative quiet wx day across
the Inland NW. /sb
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 31 42 34 41 32 45 / 50 20 10 50 40 40
Coeur d`Alene 31 43 33 41 32 44 / 60 50 10 50 40 40
Pullman 29 41 32 40 33 48 / 40 40 10 60 40 40
Lewiston 34 47 35 45 37 52 / 50 30 10 60 30 30
Colville 33 45 29 44 31 47 / 70 50 10 50 40 40
Sandpoint 30 41 30 41 32 44 / 80 60 10 40 40 50
Kellogg 32 38 26 38 31 43 / 80 60 20 50 60 50
Moses Lake 28 47 34 45 33 49 / 10 10 10 40 20 30
Wenatchee 31 47 35 44 35 47 / 20 10 10 40 20 30
Omak 31 46 33 46 34 48 / 50 10 10 50 30 40
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...Winter Weather Advisory until 11 AM PDT Thursday for Northern
Panhandle.
Winter Weather Advisory until 11 AM PDT Thursday for Central
Panhandle Mountains.
WA...Winter Weather Advisory until 11 AM PDT Thursday for Northeast
Mountains-Okanogan Highlands.
Winter Weather Advisory until 11 PM PDT this evening for East
Slopes Northern Cascades.
&&
$$
AREA FORECAST DISCUSSION
NWS SPOKANE WA
1015 PM PDT Wed Oct 24 2012
.SYNOPSIS...A band of rain and mountain snow will move through the
area today and tonight. The weather will generally be quiet on
Thursday before the next weather system arrives Friday with
additional storms for the weekend. More precipitation is expected
into early next week.
&&
.DISCUSSION...
We have made some slight adjustments to the winter weather
advisory for the remainder of the night. A band of light to moderate
precipitation continues to impact the northern mountains from the
Pasayten Wilderness...eastward to the Sandpoint, ID. A tour of
observation networks across the region suggest snow levels have
dropped some with levels across the Okanogan Highlands, NE WA
Mtns, and Nrn ID Panhandle sitting around 3K ft. As such, we have
made adjustments to the winter wx advisory to bring light
acccumulations down to these levels. In IDZ004, the Central
Panhandle Mtns, pcpn is struggling to materialize and this will
equate to the lower snow totals. The NAM...EC...and HRRR have
captured this better then the GFS and were referenced for the
remainder of the night. Despite the lack of pcpn over this region
from the stable deformation band, cellular cloud structure in
conjuction with the model 500mb temperatures suggest the
atmosphere is going to become increasingly unstable once again.
Winds behind this evening`s wave should become SW/W before
swinging to the W/NW Thursday morning. In addition, another
midlevel circulation is currently crossing the Blue Mtns and
should incr the shower activity across lower Shoshone County
overnight. All it will take is a few heavy convective showers to
get going and localized accumulations of 1-3 inches will be
possible with the convective showers.
On another note, the lack of pcpn has allowed pockets of cooler
temperatures across the Idaho Panhandle with Wallace currently
sitting at 35F with a 32F dewpoint. Bonners Ferry is also 36F over
32F and as pcpn reaches into these locations, I would not be
surprised to see snow reach these valley floors. If the pcpn
remains light, the above freezing temperatures should neglect any
impacts but if any heavier showers were to come through, light
accumulations will be possible on roadways and we will likely
handle any updates with short term forecasts based on the isolated
nature.
All things considered, we have lowered the snow advisory for the
Central Panhandle Mtns down to 2500 based on latest observations
and if the 00z GFS was to verify...1-3 inches of snow will be
easily achievable in locations like Deary, Wallace, and Lookout Pass.
The threat for steady snow has ended for the East Slopes of the
Cascades. Isolated to scattered showers will continue. Some
locations may receive the first burst of snow accumulation so far
this fall as showers become increasingly convective and
temperatures cool in between cloud shields. At the current hour, a
few heavier showers reside over southwestern Chelan county near
the Crest. Expect this unorganized activity to continue through
the night and extend into the Basin. AS such, we have included a
slight chance for showers for all locations through the remainder
of the night. /sb
&&
.AVIATION...
00Z TAFS: Another round of rain and mtn snow is currently moving
through the region and will continue to moisten an already juicy
boundary layer. Consequently, expect widespread mtn obscurations
along the northern mtns this evening and overnight. All terminals
are expected to lower to MVFR/IFR levels either with the onset of
pcpn or after the rain ends and skies briefly clear. Confidence on
a whole is low for all sites given a wide array of MOS solutions
per each TAF site. /sb
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 31 42 34 41 32 45 / 50 20 10 50 40 40
Coeur d`Alene 31 43 33 41 32 44 / 80 50 10 50 40 40
Pullman 29 41 32 40 33 48 / 50 40 10 60 40 40
Lewiston 34 47 35 45 37 52 / 80 30 10 60 30 30
Colville 33 45 29 44 31 47 / 100 50 10 50 40 40
Sandpoint 30 41 30 41 32 44 / 100 60 10 40 40 50
Kellogg 32 38 26 38 31 43 / 90 60 20 50 60 50
Moses Lake 28 47 34 45 33 49 / 0 10 10 40 20 30
Wenatchee 31 47 35 44 35 47 / 10 10 10 40 20 30
Omak 31 46 33 46 34 48 / 80 10 10 50 30 40
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...Winter Weather Advisory until 11 AM PDT Thursday for Central
Panhandle Mountains.
Winter Weather Advisory until 11 AM PDT Thursday for Northern
Panhandle.
WA...Winter Weather Advisory until 11 AM PDT Thursday for Northeast
Mountains-Okanogan Highlands.
Winter Weather Advisory until 11 PM PDT this evening for East
Slopes Northern Cascades.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
413 AM EDT SAT OCT 27 2012
.SYNOPSIS...
TROPICAL SYSTEM SANDY WILL MOVE NORTHWARD OFF THE ATLANTIC COAST
THROUGH SUNDAY. THE PRESSURE GRADIENT ASSOCIATED WITH THE SYSTEM
WILL RESULT IN BREEZY CONDITIONS IN THE FORECAST AREA. MOST OF THE
RAIN ASSOCIATED WITH SANDY WILL REMAIN EAST OF THE FORECAST AREA.
AN APPROACHING COLD FRONT WILL MOVE THROUGH THE AREA SUNDAY. THE
COLDEST AIR OF THE SEASON SO FAR WILL FOLLOW THIS FRONT.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE MODELS ARE CONSISTENT KEEPING DEEP MOISTURE EAST OF THE
FORECAST AREA TODAY. MAINTAINED JUST CHANCE POPS IN THE EAST PART
ASSOCIATED WITH MOISTURE THAT MAY WRAP INTO THE AREA. MODEL TIME-
HEIGHT DISPLAYS AND MIXING SUPPORTS FREQUENT GUSTS NEAR 25 KNOTS.
WE HAVE ISSUED A LAKE WIND ADVISORY. IT WILL BE COOLER TODAY
COMPARED TO YESTERDAY MAINLY BECAUSE OF CLOUDINESS. THE
TEMPERATURE GUIDANCE WAS CLOSE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/...
THE NAM AND GFS CONTINUE TO SHOW DEEP MOISTURE REMAINING NORTHEAST
OF THE FORECAST AREA AS SANDY MOVES NORTH-NORTHEASTWARD. THE COLD
FRONT SUNDAY STILL APPEARS DRY BECAUSE OF A LACK OF SIGNIFICANT
CONVERGENCE. THE PRESSURE GRADIENT WILL CONTINUE TO SUPPORT BREEZY
CONDITIONS AND WE HAVE MAINTAINED THE LAKE WIND ADVISORY. USED THE
GUIDANCE CONSENSUS FOR THE TEMPERATURE FORECAST.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
STRONG LOW PRESSURE IN THE MIDDLE ATLANTIC AND NORTHEAST STATES
AND RIDGING IN THE MIDDLE OF THE NATION WILL MAINTAIN NORTHWEST
FLOW INTO THE FORECAST AREA DURING THE EXTENDED PERIOD. IT WILL BE
A DRY AND COOL PERIOD. THE GFS ENSEMBLE MEANS SUPPORT LOWS IN THE
30S.
&&
.AVIATION /08Z SATURDAY THROUGH WEDNESDAY/...
SURFACE HIGH PRESSURE TO OUR NE...WITH TROPICAL SYSTEM SANDY WELL
TO OUR SOUTHEAST JUST NORTH OF THE BAHAMAS WILL PRODUCE A STEADY N
WIND ACROSS MUCH OF THE CWA BECAUSE OF THE PRESSURE GRADIENT
BETWEEN THE TWO SYSTEMS. SATELLITE LOOP SHOWS PLENTY OF HIGH
CLOUDINESS ACROSS THE ENTIRE CWA TONIGHT. SATELLITE/OBS ALSO SHOWS
THE SLOW MOVING COLD FRONT TO OUR WEST ON THE WEST SIDE OF THE
APPALACHIANS. SANDY IS FORECAST TO MOVE TO THE N AND NE FOR THE
REMAINDER OF TONIGHT INTO SATURDAY. THE BULK OF THE ASSOCIATED
MOISTURE AND PRECIPITATION ACTIVITY WILL BE STAYING EAST OF THE
TAF SITES. GUIDANCE IN AGREEMENT INDICATING LOWER CLOUDINESS FOR
MUCH OF OUR CWA AFTER MIDNIGHT TOWARD MORNING. LATEST SATELLITE
AND SURFACE OBS INDICATE LOWER CLOUDS CURRENTLY ACROSS PORTIONS OF
CENTRAL AND E NC...WITH MAINLY MVFR CIGS. LATEST RAP BRINGS LOWER
CLOUDS SW INTO OUR CWA LATE TONIGHT UNDER A N/NE LOW LEVEL FLOW.
UNCERTAINTY WITH REGARDS TO WHETHER CIGS WILL BE MVFR OR IFR. FOR
NOW...WILL MAINTAIN LOW END MVFR CIGS. BREEZY CONDITIONS EXPECTED
SATURDAY WITH PLENTY OF CLOUDINESS...MAINLY VFR AFTER 13Z/14Z.
EXPECT WINDS TO SHIFT A BIT MORE NW/NNW BY SATURDAY EVENING BUT
REMAINING UP AROUND 10 TO 15 KTS WITH PLENTY OF HIGH CLOUDS AS
SANDY WILL BE SE OF CHARLESTON.
EXTENDED AVIATION OUTLOOK...BREEZY CONDITIONS MAY CONTINUE THROUGH
MONDAY...OTHERWISE NO MAJOR RESTRICTIONS FOR AVIATION INTERESTS
EXPECTED.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...LAKE WIND ADVISORY FROM 10 AM THIS MORNING TO 10 PM EDT SUNDAY
FOR SCZ015-016-018-020>022-025>031-035>038-041.
GA...LAKE WIND ADVISORY FROM 10 AM THIS MORNING TO 10 PM EDT SUNDAY
FOR GAZ040-063>065-077.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
241 AM EDT SAT OCT 27 2012
.SYNOPSIS...
HURRICANE SANDY WILL MOVE NORTHWARD OFF THE ATLANTIC COAST
THROUGH SUNDAY. THE PRESSURE GRADIENT ASSOCIATED WITH THE SYSTEM
WILL RESULT IN BREEZY CONDITIONS IN THE FORECAST AREA. MOST OF
THE RAIN ASSOCIATED WITH SANDY WILL REMAIN EAST OF THE FORECAST
AREA. AN APPROACHING COLD FRONT WILL MOVE THROUGH THE AREA SUNDAY.
THE COLDEST AIR OF THE SEASON SO FAR WILL FOLLOW THIS FRONT.
&&
.NEAR TERM /THROUGH TODAY/...
THE MODELS ARE CONSISTENT KEEPING DEEP MOISTURE EAST OF THE
FORECAST AREA TODAY. MAINTAINED JUST CHANCE POPS IN THE EAST PART
ASSOCIATED WITH MOISTURE THAT MAY WRAP INTO THE AREA. MODEL TIME-
HEIGHT DISPLAYS AND MIXING SUPPORTS FREQUENT GUSTS NEAR 25 KNOTS.
WE HAVE ISSUED A LAKE WIND ADVISORY. IT WILL BE COOLER TODAY
COMPARED TO YESTERDAY MAINLY BECAUSE OF CLOUDINESS. THE
TEMPERATURE GUIDANCE WAS CLOSE.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
THE NAM AND GFS CONTINUE TO SHOW DEEP MOISTURE REMAINING NORTHEAST
OF THE FORECAST AREA AS SANDY MOVES NORTH-NORTHEASTWARD. THE COLD
FRONT SUNDAY STILL APPEARS DRY BECAUSE OF A LACK OF SIGNIFICANT
CONVERGENCE. THE PRESSURE GRADIENT WILL CONTINUE TO SUPPORT BREEZY
CONDITIONS AND WE HAVE MAINTAINED THE LAKE WIND ADVISORY. USED THE
GUIDANCE CONSENSUS FOR THE TEMPERATURE FORECAST.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
STRONG LOW PRESSURE IN THE MIDDLE ATLANTIC AND NORTHEAST STATES
AND RIDGING IN THE MIDDLE OF THE NATION WILL MAINTAIN NORTHWEST
FLOW INTO THE FORECAST AREA DURING THE EXTENDED PERIOD. IT WILL BE
A DRY AND COOL PERIOD. THE GFS ENSEMBLE MEANS SUPPORT LOWS IN THE
30S.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
SURFACE HIGH PRESSURE TO OUR NE...WITH HURRICANE SANDY WELL TO OUR
SOUTHEAST JUST NORTH OF THE BAHAMAS WILL PRODUCE A STEADY N WIND
ACROSS MUCH OF THE CWA BECAUSE OF THE PRESSURE GRADIENT BETWEEN THE
TWO SYSTEMS. SATELLITE LOOP SHOWS PLENTY OF HIGH CLOUDINESS ACROSS
THE ENTIRE CWA TONIGHT. SATELLITE/OBS ALSO SHOWS THE SLOW MOVING
COLD FRONT TO OUR WEST ON THE WEST SIDE OF THE APPALACHIANS. SANDY
IS FORECAST TO MOVE TO THE N AND NE FOR THE REMAINDER OF TONIGHT
INTO SATURDAY. THE BULK OF THE ASSOCIATED MOISTURE AND PRECIPITATION
ACTIVITY WILL BE STAYING EAST OF THE TAF SITES. GUIDANCE IN
AGREEMENT INDICATING LOWER CLOUDINESS FOR MUCH OF OUR CWA AFTER
MIDNIGHT TOWARD MORNING. LATEST SATELLITE AND SURFACE OBS INDICATE
LOWER CLOUDS CURRENTLY ACROSS PORTIONS OF CENTRAL AND E NC...WITH
MAINLY MVFR CIGS. LATEST RAP BRINGS LOWER CLOUDS SW INTO OUR CWA
LATE TONIGHT UNDER A N/NE LOW LEVEL FLOW. UNCERTAINTY WITH REGARDS
TO WHETHER CIGS WILL BE MVFR OR IFR. FOR NOW...WILL MAINTAIN LOW END
MVFR CIGS. BREEZY CONDITIONS EXPECTED SATURDAY WITH PLENTY OF
CLOUDINESS...MAINLY VFR AFTER 13Z/14Z. EXPECT WINDS TO SHIFT A BIT
MORE NW/NNW BY SATURDAY EVENING BUT REMAINING UP AROUND 10 TO 15 KTS
WITH PLENTY OF HIGH CLOUDS AS SANDY WILL BE SE OF CHARLESTON.
EXTENDED AVIATION OUTLOOK...BREEZY CONDITIONS MAY CONTINUE THROUGH
MONDAY...OTHERWISE NO MAJOR RESTRICTIONS FOR AVIATION INTERESTS
EXPECTED.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...LAKE WIND ADVISORY FROM 10 AM THIS MORNING TO 10 PM EDT SUNDAY
FOR SCZ015-016-018-020>022-025>031-035>038-041.
GA...LAKE WIND ADVISORY FROM 10 AM THIS MORNING TO 10 PM EDT SUNDAY
FOR GAZ040-063>065-077.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
142 AM EDT SAT OCT 27 2012
.SYNOPSIS...
HURRICANE SANDY WILL MOVE NORTHWARD OFF THE ATLANTIC COAST SATURDAY
AND SUNDAY. A STRONG PRESSURE GRADIENT WILL DEVELOP SATURDAY AND
CONTINUE THROUGH SUNDAY AS THE STORM MOVES NORTHWARD OFFSHORE.
THIS WILL CAUSE WINDY CONDITIONS SATURDAY AND SUNDAY. MOST OF THE
RAIN WILL BE CONFINED TO THE COASTAL REGION BUT THERE IS A SLIGHT
CHANCE OF SHOWERS MAKING IT INLAND AS FAR AS THE CENTRAL MIDLANDS
SATURDAY. A STRONG COLD FRONT WILL APPROACH FROM THE WEST SUNDAY
AND MOVE THROUGH SUNDAY NIGHT. THIS WILL BRING MUCH COLDER
TEMPERATURES TO THE AREA AS AN AREA OF COLD HIGH PRESSURE BUILDS
IN MONDAY THROUGH WEDNESDAY.
&&
.NEAR TERM /TONIGHT/...
A COLD FRONT WILL REMAIN TO THE WEST AS HURRICANE SANDY MOVES
NORTHWARD WELL OFFSHORE. AN INCREASING PRESSURE GRADIENT WILL HELP
TO INCREASE WINDS TO 10-15 MPH OVERNIGHT. ANY RAINFALL OVERNIGHT IS
EXPECTED TO REMAIN OFF TO THE EAST OF THE MIDLANDS AND CSRA...WITH
THE BULK OF IT REMAINING OFF THE ATLANTIC COAST. WILL STILL
INTRODUCE A SLIGHT CHANCE FOR RAINFALL ACROSS EXTREME EASTERN
AREAS TOWARDS MORNING. IT WILL BE ANOTHER WARM NIGHT WITH LOWS
MOSTLY IN THE LOWER 60S.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
THE AFFECTS OF SANDY TO THE EAST...WELL OFFSHORE...AND HIGHER
PRESSURE TO THE EAST WILL COMBINE TO CAUSE WINDS TO INCREASE TO 20
TO 30 MPH WITH GUSTS OVER 30 MPH AT TIMES SATURDAY THROUGH SUNDAY
NIGHT. MOST OF THE SHOWERS SHOULD REMAIN WELL TO THE EAST MAINLY
NEAR THE COAST BUT A WESTERN BAND OF SHOWERS COULD BRING A 20-30
PERCENT CHANCE OF SHOWERS TO THE CENTRAL MIDLANDS AND LOCATIONS TO
THE EAST. THE WESTERN PART INCLUDING THE CSRA LOOK TO BE RAIN
FREE. TEMPERATURES WILL NOT BE AS WARM SATURDAY AND SUNDAY MAINLY
DUE TO CLOUDS AND A CHANCE OF RAIN. HIGH TEMPERATURES WILL BE IN
THE LOWER TO MIDDLE 70S. THE COLD FRONT COMES THROUGH SUNDAY NIGHT
AND LOWS DROP INTO THE LOWER 40S.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
HURRICANE SANDY WILL BE GONE TO THE NORTH BY MONDAY AND
SHOULD HAVE TRANSITIONED INTO A MONSTER EXTRA-TROPICAL
STORM JUST IN TIME FOR HALLOWEEN. FORTUNATELY FOR SOUTH
CAROLINA...JUST COLD HIGH PRESSURE WILL MOVE ACROSS THE REGION.
TEMPERATURES WILL BE WELL BELOW NORMAL. HIGHS IN THE UPPER
50S TO LOWER 60S WITH LOWS IN THE MIDDLE TO UPPER 30S.
&&
.AVIATION /06Z SATURDAY THROUGH THURSDAY/...
SURFACE HIGH PRESSURE TO OUR NE...WITH HURRICANE SANDY WELL TO OUR
SOUTHEAST JUST NORTH OF THE BAHAMAS WILL PRODUCE A STEADY N WIND
ACROSS MUCH OF THE CWA BECAUSE OF THE PRESSURE GRADIENT BETWEEN THE
TWO SYSTEMS. SATELLITE LOOP SHOWS PLENTY OF HIGH CLOUDINESS ACROSS
THE ENTIRE CWA TONIGHT. SATELLITE/OBS ALSO SHOWS THE SLOW MOVING
COLD FRONT TO OUR WEST ON THE WEST SIDE OF THE APPALACHIANS. SANDY
IS FORECAST TO MOVE TO THE N AND NE FOR THE REMAINDER OF TONIGHT
INTO SATURDAY. THE BULK OF THE ASSOCIATED MOISTURE AND PRECIPITATION
ACTIVITY WILL BE STAYING EAST OF THE TAF SITES. GUIDANCE IN
AGREEMENT INDICATING LOWER CLOUDINESS FOR MUCH OF OUR CWA AFTER
MIDNIGHT TOWARD MORNING. LATEST SATELLITE AND SURFACE OBS INDICATE
LOWER CLOUDS CURRENTLY ACROSS PORTIONS OF CENTRAL AND E NC...WITH
MAINLY MVFR CIGS. LATEST RAP BRINGS LOWER CLOUDS SW INTO OUR CWA
LATE TONIGHT UNDER A N/NE LOW LEVEL FLOW. UNCERTAINTY WITH REGARDS
TO WHETHER CIGS WILL BE MVFR OR IFR. FOR NOW...WILL MAINTAIN LOW END
MVFR CIGS. BREEZY CONDITIONS EXPECTED SATURDAY WITH PLENTY OF
CLOUDINESS...MAINLY VFR AFTER 13Z/14Z. EXPECT WINDS TO SHIFT A BIT
MORE NW/NNW BY SATURDAY EVENING BUT REMAINING UP AROUND 10 TO 15 KTS
WITH PLENTY OF HIGH CLOUDS AS SANDY WILL BE SE OF CHARLESTON.
EXTENDED AVIATION OUTLOOK...BREEZY CONDITIONS MAY CONTINUE THROUGH
MONDAY...OTHERWISE NO MAJOR RESTRICTIONS FOR AVIATION INTERESTS
EXPECTED.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...LAKE WIND ADVISORY FROM 10 AM SATURDAY TO 10 PM EDT SUNDAY FOR
SCZ015-016-018-020>022-025>031-035>038-041.
GA...LAKE WIND ADVISORY FROM 10 AM SATURDAY TO 10 PM EDT SUNDAY FOR
GAZ040-063>065-077.
&&
$$
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1150 PM CDT FRI OCT 26 2012
...UPDATED FOR 27/06Z AVIATION DISCUSSION...
.SHORT TERM /TONIGHT/...
HIGH PRESSURE CURRENTLY CENTERED OVER SW NE AND NW KS WILL TRANSLATE
EASTWARD TONIGHT. THIS WILL ALLOW WINDS TO DIMINISH WITH SUNSET.
STRATUS DECK THAT HAS BEEN IN PLACE MUCH OF THE DAY HAS BECOME MORE
CELLULAR ON THE SOUTH/EASTERN EDGES AND EXPECT THAT AREA AND POINTS
FURTHER SOUTH/EAST IN THE CWA TO CLEAR OFF OVERNIGHT. MODELS HAVE
BEEN HAVING A HARD TIME DEALING WITH THIS LOWER LEVEL MOISTURE THAT
IS TRAPPED BELOW THE INVERSION. THEREFORE TEMPERATURES A BIT TRICKY
TONIGHT DUE TO UNCERTAINTY WITH THE CLOUD COVER. RAP MODEL SEEMED TO
BE LINING UP THE BEST WITH ITS 925-850MB RH FIELD...THEREFORE
TRENDED SKY COVER TOWARD THAT MODEL. THIS SOLUTION ALSO SUGGESTS THE
CLEARING IN THE AFOREMENTIONED AREAS AND THE LOWER CLOUDS LINGERING
ACROSS THE WEST CENTRAL/NORTHWESTERN CWA THROUGH THE NIGHT.
THEREFORE HAVE KEPT TEMPS A LITTLE WARMER DUE TO THE CLOUD
COVER...BUT STILL A LITTLE COOLER FROM READINGS LAST NIGHT DUE TO
THE UNCERTAINTY WITH THE CLOUD COVER.
.LONG TERM /SATURDAY THROUGH FRIDAY/...
WITH ALL EYES ON THE EAST COAST AND EVOLUTION OF SANDY...IA WEATHER
WILL BE TRANQUIL WITH SEASONALLY COOL TEMPERATURES. ONLY NEAR TERM
WINDOW FOR PRECIP WILL BE WITH SHORT WAVE CURRENTLY OFF BC COAST
WHICH DROPS INTO MO VALLEY SAT NIGHT. MODELS HAVE TRENDED SLIGHTLY
NORTH AND WEST WITH ITS FORCING AND MOISTURE SO HAVE REMOVED
MEASURABLE POPS WITH NOTHING BEYOND FLURRY WORDING FAR NW 09-15Z SAT.
A SIMILAR SHORT WAVE EJECTING OUT OF THE PACIFIC NW THIS WEEKEND
WILL DROP INTO THE BASE OF THE MS/OH VALLEY LONG WAVE TROUGH AND
EVENTUALLY PHASE WITH SANDY. THIS IMPRESSIVE STORM...WHERE EVER ITS
LOCATION AND LANDFALL...WILL BE SLOW MOVING AND LOCK IN OUR PATTERN
KEEPING IA IN PERSISTENT RELATIVELY DRY NW FLOW AND NEAR NORMAL
TEMPERATURES. ALTHOUGH CONFIDENCE AND MODEL CONSENSUS IS NOT GREAT
ENOUGH TO INTRODUCE MEASURABLE POPS AT THIS POINT...TOKEN PRECIP
MENTION MAY EVENTUALLY BE NEEDED AROUND MON OR TUE...AND AGAIN
AROUND THU. TEMPERATURES WILL BE FAIRLY STEADY THROUGH THE ENTIRE
PERIOD WITH GENERALLY LIGHT WINDS AND LITTLE CHANGE IN AIRMASS.
&&
.AVIATION...27/06Z
VFR CONDITIONS EXPECTED THROUGH THE PERIOD. LOW END VFR STRATUS
DECK OVER KDSM/KMCW/KFOD CONTINUES TO SLOWLY LIFT AND SHRINK IN
COVERAGE. THIS TREND SHOULD CONTINUE THROUGH THE OVERNIGHT HOURS
KEEPING ALL CIGS VFR. SURFACE RIDGE WILL SLIDE FROM WEST TO EAST
ACROSS TAF SITES SATURDAY...CAUSING WINDS TO BECOME LIGHT AND
VARIABLE. AN UPPER LEVEL DISTURBANCE WILL DROP SOUTHEAST AND BRING
SOME HIGH CLOUDS TO ALL SITES BY THE END OF THE PERIOD...BUT ALL
CIGS WILL ONCE AGAIN REMAIN VFR.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...BEERENDS
LONG TERM...SMALL
AVIATION...DEITSCH
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1217 AM CDT SAT OCT 27 2012
...UPDATED AVIATION SECTION...
.SHORT TERM...(THIS EVENING THROUGH TOMORROW) ISSUED AT 302 PM CDT FRI
OCT 26 2012
A FAST MOVING SHORTWAVE TROUGH WAS OVER EASTERN COLORADO AND WESTERN
KANSAS THIS MORNING. THIS SYSTEM BROUGHT SOME MEASURABLE SNOW TO FAR
WESTERN PORTIONS OF SOUTHWEST KANSAS. BY EARLY AFTERNOON THE
SHORTWAVE HAD MOVED INTO EASTERN KANSAS WITH CLEARING SKIES IN ITS
WAKE. THERE WAS SOME LINGERING STRATUS ALONG WITH LIGHT SNOW
FLURRIES OUT ALONG THE COLORADO BORDER BEING FORCED BY SOME WEAK PVA
AND LOW LEVEL UPSLOPE. RUC13 MODEL CROSS SECTIONS SHOW THIS AREA OF
CLOUDS/PRECIPITATION DECREASING THROUGH THE NEXT FEW HOURS. VISIBLE
SATELLITE LOOPS SHOW THE AREA OF STRATUS ALREADY STARTING TO
DIMINISH. SKIES SHOULD BE MOSTLY CLEAR ACROSS ALL OF SOUTHWEST
KANSAS BY THIS EVENING.
WITH THE COLD HIGH PRESSURE AIRMASS IN PLACE ACROSS WESTERN KANSAS,
CLEAR SKIES AND LIGHT WINDS THIS EVENING WILL RESULT IN TEMPERATURES
FALLING TO BELOW FREEZING FAIRLY SOON AFTER SUNSET. OVERNIGHT LOWS
WILL BE FALLING INTO THE LOWER TO MIDDLE 20S ACROSS THE ENTIRE AREA
OVERNIGHT. WITH THIS IN MIND, WILL CONVERT THE HARD FREEZE WATCH TO
A HARD FREEZE WARNING FOR THE AREA ALONG AND SOUTH OF A LINE FROM
JOHNSON TO JETMORE AND LARNED. THE AREA FROM SYRACUSE THROUGH
DIGHTON SAW A GOOD FREEZE LAST NIGHT SO THEY ARE DONE FOR THE YEAR
AS ARE AREAS UP TOWARD I-70. ANOTHER WEAK AND FAST MOVING SHORTWAVE
TROUGH WILL BE APPROACHING THE CENTRAL HIGH PLAINS LATER TONIGHT.
THIS COULD SPREAD SOME HIGH CLOUDINESS INTO PARTS OF WESTERN KANSAS.
IN ADDITION, THE SURFACE HIGH PRESSURE WILL BE MOVING INTO EASTERN
KANSAS LATER TONIGHT WHILE PRESSURE FALLS WILL ENSUE ALONG THE
EASTERN SLOPES OF THE ROCKIES. THIS COULD RESULT IN TEMPERATURES
RISING SOMEWHAT LATE TONIGHT.
SOUTHERLY WINDS WILL BECOME GUSTY FROM THE SOUTH ON SATURDAY AS THE
SURFACE PRESSURE GRADIENT INCREASES. ONLY SOME SCATTERED HIGH
CLOUDINESS IS EXPECTED DURING THE DAY. BASED ON MODEL 850
TEMPERATURE FORECASTS, HIGHS ON SATURDAY SHOULD ONLY CLIMB INTO THE
LOWER 50S IN MOST AREAS.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 321 PM CDT FRI OCT 26 2012
SOUTHERLY WINDS WILL BECOME ESTABLISHED BY OVERNIGHT SATURDAY, BUT
TEMPERATURES WILL LIKELY STILL FALL TO AROUND FREEZING WITH LIGHT
WINDS AND SUCH A DRY AIRMASS. THE ECMWF AND GFS ARE VERY SIMILAR IN
THE GENERAL MASS FIELDS FOR SUNDAY. SIMILARITIES ARE MOST
PRONOUNCED IN THE MID LEVEL RELATIVE HUMIDITY FIELDS, ASSOCIATED
WITH REMNANTS OF A NORTHERN PLAINS SHORTWAVE AND THE UPPER JET
DIVING THROUGH THE GREAT PLAINS FROM NORTH TO SOUTH. THIS COULD LEAD
TO CONSIDERABLE ALTOSTRATUS OR AT LEAST HIGH CIRRUS CLOUDS FOR
CENTRAL KANSAS FOR A GOOD PORTION OF THE DAY. THERMAL FIELDS DIFFER
CONSIDERABLE HOWEVER, ESPECIALLY WITH RESPECT TO HOW FAST THE GFS
WARMS THE BOUNDARY LAYER APPROXIMATED BY 850 MB TEMPERATURES. GFS IS
GENERALLY MUCH WARMER WHICH REFLECTS IN MODEL`S AFTERNOON HIGHS.
GIVEN HOW MUCH OF A WARM BIAS SEVERAL FORECAST DAYS HAVE BEEN
RECENTLY, WE`LL FOLLOW THE COOLER ECMWF IDEA, BUT USE GFS MOS
TEMPERATURES THAT ARE COOLER IN THE WEST.
A DRY PATTERN WILL BE ESTABLISHED THROUGH THE REMAINDER OF THE WEEK.
THE SYNOPTIC PATTERN INCLUDES A WEDGE OF RELATIVE SURFACE HIGH
PRESSURE ANCHORED FROM THE UPPER MIDWEST...SOUTHWEST ACROSS THE MID
MISSISSIPPI VALLEY INTO NORTHEAST TEXAS. WITH THE EXPECTED HURRICANE
OR TROPICAL STORM SPREADING WESTWARD INTO THE EASTERN TROUGH. THAT
PATTERN WILL MAINTAIN THE UPPER RIDGE FROM TUESDAY INTO THURSDAY
RIGHT OVER THE HIGH PLAINS REGIONS. LIGHT SOUTHERLY SURFACE WINDS
WILL BE THE PREVAILING WIND DIRECTION. HIGHS WILL INCREASE THROUGH
THE 60S, AND REACH THE LOW 70S WEDNESDAY OR THURSDAY. HIGHER
SURFACE DEW POINT INCREASING BACK INTO THE 30S WILL BRING OVERNIGHT
LOWS BACK ABOVE FREEZING THROUGH THE PERIOD AS WELL. BY FRIDAY, THE
UPPER FLOW BECOMES STRONGLY DIVERGENT ACROSS THE REGION AS A SHARP
TROUGH MOVES ACROSS THE WESTERN STATES, WHICH IS MODELED BY BOTH THE
GFS AND ECMWF. IN EITHER INSTANCE, THE WEATHER TYPE FOR THE REGION
APPEARS TO BE PRIMARILY WET - SHOWERS OR THUNDERSTORMS, BUT THE
MESOSCALE DETAILS ARE HIGHLY UNCERTAIN AT THIS TIME, AND COULD MISS
WESTERN KANSAS ALTOGETHER.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1210 AM CDT SAT OCT 27 2012
SURFACE HIGH PRESSURE WILL CONTINUE TO SLIDE SOUTHEAST OVERNIGHT
AND INTO THE MORNING. ON THE BACKSIDE OF THE CENTER OF THE HIGH
SURFACE WINDS WILL BECOME SOUTHERLY DURING THE DAY. SOME GUSTS TO
AROUND 20KT WILL DEVELOP. LEE SIDE CIRRUS WILL MOVE ACROSS THE
REGION DURING THE DAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 28 59 32 63 / 0 0 0 0
GCK 28 59 31 65 / 0 0 0 0
EHA 29 59 34 66 / 0 0 0 0
LBL 29 61 33 64 / 0 0 0 0
HYS 26 57 32 64 / 0 0 0 0
P28 28 59 34 63 / 0 0 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
HARD FREEZE WARNING UNTIL 9 AM CDT THIS MORNING FOR KSZ064>066-
074>081-084>090.
&&
$$
SHORT TERM...GERARD
LONG TERM...RUSSELL
AVIATION...HUTTON
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1147 PM CDT FRI OCT 26 2012
...UPDATE TO AVIATION...
.DISCUSSION...
SHORT TERM FORECAST - TONIGHT AND SATURDAY...
AT 19Z RAP SURFACE ANALYSIS INDICATED A RIDGE OF HIGH PRESSURE
LOCATED ROUGHLY ACROSS WESTERN NEBRASKA AND WESTERN KANSAS...WITH
THE RIDGE AXIS RUNNING FROM KBBW SOUTHWESTWARD TO KGLD. ALONG THE
EASTERN EDGE OF THE AREA OF HIGH PRESSURE NORTHERLY WINDS CONTINUE
TO ALLOW COOLER AIR TO TRICKLE INTO EASTERN KANSAS. AS THE RIDGE
MOVES EASTWARD THE AXIS WILL BECOME CENTERED OVER THE FORECAST AREA
TONIGHT...WHICH WILL CAUSE WINDS TO BECOME CALM AND SKIES TO BECOME
MOSTLY CLEAR TO PARTLY CLOUDY. THE COMBINATION OF THE TWO EFFECTS
WILL BRING VERY CHILLY TEMPERATURES TO THE REGION FOR THE OVERNIGHT
HOURS. EXPECT TEMPS TO DROP INTO THE LOWER TO MID 20S ACROSS THE
ENTIRE AREA...WITH LOW LYING SUCH AS RIVER VALLEYS TO DROP INTO THE
UPPER TEENS TO LOWER 20S. AS THE SURFACE HIGH MOVES TO THE EAST
SOUTHERLY FLOW WILL GRADUALLY PICK UP ON THE BACK/WEST SIDE OF THE
DEPARTING RIDGE...WHICH WILL COMMENCE A SLOW WARM UP TREND...WHICH
WILL CONTINUE THROUGH THE WEEKEND. EXPECT HIGHS ON SATURDAY TO BE
SLIGHTLY WARMER THAN FRIDAY`S HIGHS...BUT WITH HIGH CLOUDS MOVING
THROUGH THE AMOUNT OF WARMING FOR SATURDAY WILL BE MARGINAL...SO
WILL EXPECT HIGHS TO GENERALLY BE IN THE LOWER TO MID 50S.
JL
LONG TERM - SATURDAY NIGHT THROUGH FRIDAY...
THE ENTIRE PERIOD IS FORECAST TO BE TRANQUIL AND ESSENTIALLY
PRECIPITATION FREE. NORTHWEST UPPER LEVEL FLOW WILL PERSIST ACROSS
THE REGION WITH INCREASED UPPER LEVEL RIDGING WITH TIME. MAY SEE
A FEW PERIODS OF INCREASED CLOUD COVER AS A SERIES OF VERY WEAK
DISTURBANCES MOVES THROUGH THE NORTHWEST FLOW BETWEEN NOW AND
WEDNESDAY...BUT NO PRECIPITATION IS EXPECTED WITH THESE SYSTEMS
GIVEN LACK OF MOISTURE AND ONLY WEAK ASCENT. EXPECT A GRADUAL WARM
UP WITH THE INCREASED RIDGING...PARTICULARLY DURING THE SECOND
HALF OF THE WEEK AS MODEL GUIDANCE IS CONSISTENT IN BRINGING A
FAIRLY STRONG SHORT WAVE TROUGH ACROSS THE ROCKIES BY NEXT
WEEKEND. ANY PRECIPITATION ASSOCIATED WITH THIS TROUGH WOULD
LIKELY HOLD OFF UNTIL FRIDAY NIGHT OR LATER...BUT WARMING
TEMPERATURES AND AN INCREASE IN LOW LEVEL MOISTURE IN ADVANCE OF
THE SYSTEM MAY BE NOTICED AS EARLY AS THURSDAY.
BARJENBRUCH
&&
.AVIATION...
SFC HIGH PRESSURE RIDGE STILL EXPECTED TO MOVE ACROSS THE TAF
SITES THROUGH SUNRISE WHICH WILL KEEP WINDS VERY LIGHT/CALM
AND FROM THE NORTH TO NORTHEAST...BECOMING EAST/SOUTHEASTERLY AFT
15Z. WILL CONTINUE WITH VFR CONDITIONS WITH SCT-BKN AROUND 15KFT.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1226 AM CDT SAT OCT 27 2012
.AVIATION...FOR THE KLBF AND KVTN TERMINALS THROUGH 06Z SUNDAY.
SCATTERED TO BROKEN MID AND HIGH CLOUDINESS AOA 12000 FT AGL...WILL
IMPACT THE KLBF AND KVTN TERMINALS OVER THE NEXT 24 HRS. THIS IS IN
RESPONSE TO A MID LEVEL TROUGH OF LOW PRESSURE...WHICH WILL TRACK
ACROSS THE CENTRAL AND NORTHERN PLAINS TONIGHT THROUGH SATURDAY.
WINDS WILL BE FROM THE SOUTH OR SOUTHWEST AT 10 TO 15 KTS THROUGH
00Z SUNDAY...DECREASING TO UNDER 10 KTS AFTER SUNSET SATURDAY
EVENING.
&&
.PREV DISCUSSION... /ISSUED 638 PM CDT FRI OCT 26 2012/
AVIATION...FOR THE KLBF AND KVTN TERMINALS THROUGH 00Z SUNDAY.
A LOW CONFIDENCE AVIATION FCST CONTINUES ACROSS WESTERN AND NORTH
CENTRAL NEBRASKA THIS EVENING THANKS TO PESKY STRATUS...WHICH
REMIANS IN PLACE ACROSS WESTERN AND NORTH CENTRAL NEBRASKA. BOTH THE
NAM AND GFS SOLNS CONTINUE TO HAVE A POOR HANDLE ON THE LOW LEVEL
MOISTURE FIELD AND UTILIZED THE RAP SOLN FOR CLOUD COVER THIS
EVENING INTO THE OVERNIGHT. THIS YIELDS BROKEN TO OVERCAST SKIES AON
2500 FT AGL AT THE KLBF TERMINAL AT LEAST THROUGH 09Z. AT THE KVTN
TERMINAL...SCATTERED CLOUDINESS IS EXPECTED AND SATELITE PICS ARE
INDICATING SOME LIMITED CLEARING ACROSS NWRN NEBRASKA. CIGS SHOULD
SCATTER OUT IN THE LOW LEVELS AT KLBF...HOWEVER...MID AND HIGH LEVEL
CLOUDINESS WILL CONTINUE TO STREAM INTO WESTERN AND NORTH CENTRAL
NEBRASKA FROM THE WEST...LEADING TO BROKEN CIGS AOA 10000 FT AGL
SATURDAY. LIGHT SOUTHWESTERLY WINDS WILL SHIFT TO THE SOUTH LATER
TONIGHT AND REMAIN IN THE 5 TO 10 KT RANGE. ON SATURDAY...WINDS WILL
SHIFT TO THE SOUTHWEST AND WEST AT AROUND 10 KTS AND REMAIN THERE
INTO THE AFTERNOON HOURS.
PREV DISCUSSION... /ISSUED 344 PM CDT FRI OCT 26 2012/
SYNOPSIS...
SURFACE HIGH PRESSURE CENTERED OVER MCCOOK NEBR. WEAK WINDS
CIRCULATING AROUND THE HIGH WITH CONSIDERABLE LOW AND MID CLOUDS
ACROSS THE REGION. DUE TO LACK OF MIXING AND SUN...TEMPERATURES
CONTINUE TO REMAIN CHILLY IN THE LOWER AND MID 30S. SOME CLEARING IN
THE PANHANDLE.
SHORT TERM...TONIGHT THROUGH MONDAY
LOW CLOUDS WILL THIN OUT ACROSS THE NORTHWEST THIS EVENING WHILE
LIKELY PERSISTING ACROSS THE SOUTHEAST. MEANWHILE...UPSTREAM
DISTURBANCE CURRENTLY LOCATED OVER NORTHERN IDAHO AND SOUTHWEST
MONTANA IS FORECAST TO MOVE SOUTHEAST BRINGING AN INCREASE IN MID
AND HIGH CLOUDINESS OVERNIGHT. THEREFORE THE BALANCE OF THE NIGHT TO
REMAIN MOSTLY CLOUDY. DESPITE SUCH COOL TEMPS THIS AFTERNOON IN THE
MID 30S...CLOUD COVER WILL HELP KEEP LOWS IN THE LOWER/MID 20S.
AS DISTURBANCE MOVES THROUGH WESTERN NEBRASKA SATURDAY...KEPT A
SLIGHT CHANCE FOR RAIN OR SNOW ACROSS NORTH CENTRAL NEBRASKA FOR THE
AFTERNOON/EVENING. THIS HAS BEEN INDICATED FAIRLY CONSISTENTLY BY
THE GFS...WHILE THE NAM...SREF AND ECMWF REMAIN MOSTLY DRY. MOSTLY
CLOUDY WITH HIGHS AGAIN TO RANGE BELOW NORMAL FROM NEAR 50 IN
SOUTHERN AREAS TO THE MID 40S NORTH CENTRAL.
UPPER RIDGING OCCURS ACROSS THE WESTERN CONUS SUNDAY...WHILE
NORTHWEST FLOW ALOFT STILL WILL EXIST ACROSS THE CENTRAL PLAINS.
WILL SEE A SLIGHT WARMUP DUE TO A RETURN FLOW OF LIGHT SOUTHERLY
WINDS AND HIGHS REACHING THE UPPER 50S FAR SOUTHWEST TO UPPER 40S
NORTHEAST.
MILDER YET FOR MONDAY. UPPER RIDGE TO ADVANCE FURTHER EAST INTO THE
CENTRAL ROCKIES WHILE NEGATIVELY TILTED UPPER TROUGH IN THE EASTERN
CONUS. A MORE PRONOUNCED LEESIDE TROUGH ALONG THE HIGH PLAINS. HIGHS
FROM UPPER 60S FAR SOUTHWEST TO UPPER 50S NORTHEAST.
LONG TERM...TUESDAY THROUGH FRIDAY
HURRICANE SANDY FORECAST TO REACH THE MID ATLANTIC COAST EARLY
TUESDAY...SOMEWHERE NEAR OR NORTH OF THE DELMARVA PENINSULA. THIS
TO RESULT IN A BLOCKING PATTERN WITH AN UPPER RIDGE TO AMPLIFY
ACROSS THE CENTRAL CONUS THROUGH FRIDAY. DRY AND MILD CONDITIONS
THROUGH THURSDAY WITH HIGHS FROM THE UPPER 50S TO UPPER 60S ARE
LIKELY...INCLUDING HALLOWEEN DAY.
THERE WILL BE A WESTERN TROUGH WHICH MAY EITHER BECOME CLOSED OFF
NEAR THE FOUR CORNERS REGION PER GFS SOLUTION...OR AS AN OPEN WAVE
APPROACHING THE CENTRAL PLAINS PER THE ECMWF. HAVE A SLIGHT CHANCE
FOR RAIN SHOWERS FRIDAY AND HIGHS NEAR 60. MEDIUM RANGE MODEL
AGREEMENT COULD EVENTUALLY BRING ENHANCED CHANCES HOWEVER.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
AVIATION...JWS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
225 AM EDT SAT OCT 27 2012
.SYNOPSIS...
HIGH PRESSURE WILL WEAKEN AND RETREAT NORTH AS SANDY MOVES TO THE
NORTH AND NORTHEAST...OFFSHORE OF THE CAROLINAS. THE INFLUENCE OF
SANDY WILL CONTINUE OVER THE REGION AT LEAST INTO EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH SATURDAY/...
AS OF 1000 PM FRIDAY...
THE FIRST OUTER RAINBAND ASSOCIATED WITH HURRICANE SANDY...WHICH IS
EAST OF VERO BEACH FL THIS EVENING... HAS PUSHED NORTHWEST TO JUST
OFF THE SC COAST AS DRY AIRS INFILTRATES THE SYSTEM FROM THE SOUTH.
HOWEVER...THE BAND IS ESSENTIALLY STATIONARY WITH INDIVIDUAL SHOWERS
MOVING SOUTHWEST...PARALLEL TO THE CAROLINA COASTLINES AND LITTLE
PRECIP ONSHORE. THERE HAVE BEEN A FEW ISOLATED POCKETS OF LIGHT
RAIN MOVING INLAND ACROSS THE NC COASTAL PLAIN THIS EVENING...MAKING
AS FAR WEST AS THE TRIANGLE AS OF 01Z. THE RAP INDICATES THIS VERY
LIGHT PRECIP WILL PUSH WEST TOWARD THE TRIAD OVERNIGHT AS THE FLOW
VEERS SLIGHTLY TO EASTERLY BETWEEN 925MB AND 850MB ...WITH
ADDITIONAL UPSLOPE PRECIP ALONG THE MOUNTAINS BY DAYBREAK.
OTHERWISE...THE SLOW MOVEMENT OF HURRICANE SANDY...ALONG WITH A WEAK
DRY AIR RIDGE EXTENDING SOUTH FROM ENGLAND INTO THE PIEDMONT WILL
KEEP AREAS WEST OF I-95 DRY OVERNIGHT. OVERALL...THERE HAS BEEN A
SMALL EASTWARD SHIFT AMONG THE OPERATIONAL MODELS REGARDING
SANDY...AND ACCORDINGLY A SIMILAR SHIFT IN THE PRECIP/NO PRECIP
LINE. THUS...THERE IS NO NEED TO ALTER THE OVERNIGHT POPS VERY
MUCH...AND SUBSEQUENT SHIFTS MAY NEED TO TRIM POPS ON THE WESTERN
EDGE IF THE GUIDANCE TREND CONTINUES TONIGHT.
TO THE WEST...THE SURFACE COLD FRONT HAS BEEN MAKING SLOW PROGRESS
TOWARD THE WESTERN SLOPES OF THE MOUNTAINS AND NOW EXTENDS FROM NEAR
BIRMINGHAM TO KNOXVILLE TO EAST OF PITTSBURGH. THERE IS VERY
LITTLE PRECIP WITH THE FRONT...OUTSIDE OF AN AREA OF ANAFRONTAL
PRECIP OVER THE EASTERN GREAT LAKES. THE FRONT WILL CONTINUE TO
SLOW OVERNIGHT AND EVENTUALLY CROSS THE MOUNTAINS LATER SATURDAY AS
IT BECOMES ABSORBED INTO THE FLOW AROUND SANDY. AHEAD OF THE
FRONT...LOWS TONIGHT WILL BE SOMEWHAT MILD...MOSTLY UPPER 50S TO
LOWER 60S. HAVE TWEAKED LOWS IN THE SOUTHEAST A COUPLE DEGREES
BASED ON CURRENT READINGS. EXPECT MAINLY STRATUS IN THE EAST WITH A
SLOWLY INCREASING NORTH-NORTHEASTERLY WIND TO 10-15 MPH IN THE
SOUTHEAST BY 12Z SATURDAY. -BLS
SATURDAY:
THE FORECAST TRACKS FOR HURRICANE SANDY THROUGH 00Z SUNDAY BASED ON
THE 00Z ECMWF AND THE 12Z GFS ARE PRETTY SIMILAR...WITH THE GFS
STILL A LITTLE FARTHER EAST. HOWEVER...THE LITTLEST CHANGE IN TRACK
TO THE EAST OR WEST WILL HAVE A BIG IMPACT ON THE PRECIPITATION
FORECAST FOR SATURDAY. THE LATEST FORECAST FROM THE ECMWF (HPC`S
PREFERENCE) HAS MOVED THE TRACK OF SANDY WEST AGAIN AND IS ONE OF
THE WETTEST SOLUTIONS FOR CENTRAL NC. GIVEN THAT THERE IS STILL SOME
UNCERTAINTY WITH REGARD TO THE TRACK...HAVE MADE LITTLE CHANGE TO
THE PRECIP CHANCES SATURDAY. WITH SANDY TRACKING APPROXIMATELY
PARALLEL...AND A FEW HUNDRED MILES OFFSHORE OF THE ATLANTIC
COAST...THE BEST CHANCES FOR PRECIP WILL BE ALONG THE NC COAST AND
DECREASING FROM EAST TO WEST. HAVE INCREASED PRECIP AMOUNTS EAST OF
I-95. WITH THE STRONG PRESSURE GRADIENT OVER THE AREA...WINDS WILL
ALSO BE SIGNIFICANT...MAINLY NNE...SUSTAINED OF 15 KTS WITH GUSTS OF
30-35 KTS ACROSS THE SOUTH AND EAST AND SUSTAINED NEAR 12 WITH GUSTS
OF 20-30 KTS FROM RALEIGH WEST. AS WITH THE RAIN...WINDS WILL ALSO
INCREASE FROM WEST TO EAST. THE COLD FRONTAL PASSAGE WILL BE MASKED
BY THE COASTAL SYSTEM...BUT COMBINED WITH THE CLOUD COVER AND
PRECIP...WILL RESULT IN HIGHS SATURDAY IN THE 60S.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/...
AS OF 255 PM FRIDAY...
SATURDAY NIGHT THROUGH SUNDAY NIGHT...
MODEL GUIDANCE IN GENERALLY GOOD AGREEMENT WITH THE WELL OFFSHORE
TRACK OF TROPICAL CYCLONE SANDY... PARALLELING THE SE U.S. COAST
THROUGH SUNDAY MORNING...THEN THE NC COAST SUNDAY INTO SUNDAY NIGHT.
ECMWF IS MUCH STRONGER (AS MUCH AS 15-18MB) COMPARED TO THE GFS.
PAST PERFORMANCE OF THE ECMWF WITH TROPICAL SYSTEMS SUGGEST THAT THE
ECMWF MAY BE WAY TOO STRONG/DEEP WITH SANDY. AT 18Z...THE 00Z ECMWF
VERIFIED 7MB TOO DEEP. THIS MODEL FLAW MAY COME INTO PLAY CONCERNING
PRECIP AMOUNTS AND WIND INTENSITY OVER THE COASTAL PLAIN OF NC.
EXPECT THE STRONGEST WINDS CAUSED BY THE PRESSURE GRADIENT BETWEEN
AN CANADIAN HIGH OVER ONTARIO AND TC SANDY TO AFFECT OVER EASTERN
COUNTIES LATE SATURDAY NIGHT THROUGH SUNDAY NIGHT. USED THE NHC TCM
WINDS WITH A REDUCTION OF 30 PERCENT DUE TO LAND FRICTION. GUSTS
ACHIEVED UTILIZING THE LATEST RESEARCH PERFORMED BY C*STAR
INITIATIVE CONCERNING TROPICAL WIND FORECASTING. WIND GUSTS 35-40
MPH HIGHLY PROBABLE OVER SECTIONS OF THE COASTAL PLAIN. A LITTLE
EARLY TO ISSUE A WIND ADVISORY AT THIS TIME BUT IF THE SCENARIO
REMAINS THE SAME...AN ADVISORY MAY BE NECESSARY FOR SATURDAY NIGHT
THROUGH SUNDAY EVENING.
STILL APPEARS THAT PRECIP WILL BECOME WIDESPREAD OVER THE EAST HALF
OF CENTRAL NC BY SATURDAY AFTERNOON-EARLY EVENING AS A STRONG UPPER
JET OVER THE GREAT LAKES AND A DECENT MID LEVEL S/W CROSSING THE OH
VALLEY INCREASES MID LEVEL LIFT IN THE MOIST AIR MASS ON THE NW
QUADRANT OF SANDY. EXPECT THIS PRECIP BAND TO DRIFT SLOWLY ENE
SATURDAY NIGHT INTO EARLY SUNDAY.
MODELS DIVERGE AFTER 12Z SUNDAY WITH THE GFS TAKING SANDY FARTHER
OFFSHORE THAN ECMWF WITH A DISTINCT DRYING TREND OVERSPREADING
CENTRAL NC FROM THE SW. THE ECMWF MAINTAINS A WELL DEFINED MID LEVEL
TROUGH OVER THE NORTHERN COASTAL PLAIN ALONG WITH STRONG UPPER
DIVERGENCE SUPPLIED BY A 140+ JET OVER THE EASTERN GREAT LAKES.
CONFLUENCE ALONG THIS MID LEVEL TROUGH WOULD SUGGEST A CONTINUED
THREAT FOR MODERATE TO LOCALLY HEAVY RAIN OVER THE NORTHERN COASTAL
PLAIN. HOWEVER...SINCE THE ECMWF LIKELY TOO DEEP/STRONG WITH THE
SYSTEM...CONFLUENCE ALONG TROUGH MAY BE OVERDONE. DUE TO THE
CONSISTENCY OF THE ECMWF...HAVE LEANED HEAVILY TOWARD PER TRACK AND
WEATHER DEPICTION BUT THINK THAT ITS RAINFALL PRODUCTION OVERBLOWN
BY A FACTOR OF 2. THUS EXPECT RAINFALL AMOUNTS LATE SATURDAY THROUGH
SUNDAY AFTERNOON BETWEEN 1 AND 3 INCHES EAST OF HIGHWAY 1 WITH THE
HIGHEST AMOUNTS IN VICINITY OF THE NORTHERN COASTAL DUE TO PRESENCE
OF LINGERING MID LEVEL TROUGH.
LITTLE CHANGE IN TEMPS THIS PERIOD FROM THE PREVIOUS FORECAST.
EXPECT NOTICEABLY COOLER CONDITIONS AREAWIDE SUNDAY INTO SUNDAY
NIGHT.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 255 PM FRIDAY...
MONDAY THROUGH FRIDAY...
SANDY WILL BE THE DOMINATE WEATHER FEATURE THIS PERIOD. MODEL
GUIDANCE STILL OFFERING VARYING SOLUTIONS. ECMWF HAS BEEN THE MOST
CONSISTENT WHILE THE GFS HAS SHOWN SOME RUN-TO RUN VARIANCE. WILL
BASE BULK OF FORECAST ON THE ECMWF WITH ADJUSTMENT DUE TO EXPECTED
POSITION AND STRENGTH.
S/W IN THE NORTHERN STREAM WILL ATTAIN A NEGATIVE TILT AND DRAW
SANDY NWWD. ECMWF DOES THIS ABOUT 24 HOURS SOONER COMPARED TO THE
12Z GFS...DRAWING SANDY INTO THE CHESAPEAKE BAY REGION MONDAY WHILE
THE 12Z GFS HAS ITS WWD MOVEMENT MONDAY NIGHT INTO
TUESDAY...ALLOWING SANDY TO MOVE FARTHER NORTH BEFORE SWINGING INTO
SOUTHERN NEW ENGLAND.
WITH SANDY PROJECTED TO LIE TO OUR NORTH...EXPECT CONTINUED WNW
FLOW ACROSS OUR REGION THROUGH AT LEAST WEDNESDAY. DEEP CYCLONIC
CURVATURE WILL LIKELY MAINTAIN CLOUDINESS AND PATCHES OF RAIN OVER
OUR FAR N-NE COUNTIES MONDAY THROUGH TUESDAY ALONG WITH BREEZY/WINDY
CONDITIONS. FARTHER SOUTH...DOWNSLOPE COMPONENT OF THE LOW-MID LEVEL
WINDS SHOULD AID TO SCOUR OUT THE MOISTURE AND LEAD TO CLEARING
SKIES OVER THE SOUTHERN PIEDMONT-SANDHILLS AND SOUTHERN COASTAL
PLAIN. LOW LEVEL FLOW WILL ALSO ADVECT MUCH COOLER AIR INTO CENTRAL
NC. LOW LEVEL THICKNESSES CLUSTER AROUND 1295-1300M BOTH TUESDAY
MORNING AND WEDNESDAY MORNING. HISTORICALLY...THESE VALUES SUGGEST
MIN TEMPS IN THE UPPER 20S TO LOWER 30S. THICKNESSES HAVE TRENDED
SLIGHTLY WARMER COMPARED TO 24-48 HOURS AGO. IN ADDITION...STRONG
MIXING AND POSSIBILITY OF CLOUDINESS SHOULD KEEP TEMPS UP. MAY SEE
BETTER POTENTIAL FOR A LIGHT FREEZE IN SECTIONS OF THE PIEDMONT
EARLY WEDNESDAY AND/OR THURSDAY MORNING AS SURFACE WINDS MAY HAVE A
BETTER CHANCE TO DECOUPLE AND SKIES MAY BE CLEAR. OTHERWISE WITH
THICKNESSES AS MUCH AS 50M BELOW NORMAL...EXPECT MAX TEMPS 12-18
DEGREES BELOW NORMAL MONDAY-WEDNESDAY WITH SOME MODIFICATION
THURSDAY INTO FRIDAY. AFTERNOON TEMPS IN THE 50S EXPECTED FOR MOST
OF NEXT WEEK WITH SOME UPPER 40S PROBABLE TUESDAY ACROSS THE NW
PIEDMONT.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
AS OF 225 AM FRIDAY...
24 HOUR TAF PERIOD...
IFR CONDITIONS DOMINATE ACROSS THE CENTRAL NC TAF LOCATIONS AT 06Z
WITH OCCASIONAL MVFR CONDITIONS REPORTED AT KFAY. A MOIST
NORTHEAST FLOW ASSOCIATED WITH HURRICANE SANDY WILL RESULT IN IFR
CONDITIONS PERSISTING THROUGH THE OVERNIGHT INTO THE EARLY
MORNING HOURS ON SATURDAY AS LOW STRATUS CEILINGS AND VSBYS DOWN
INTO THE 3-5 MILE RANGE PREDOMINATE. A NORTHERLY FLOW AT 6-12KTS
WITH OCCASIONAL GUSTS TO 12-20KTS IS EXPECTED OVERNIGHT.
EXPECT A SHIELD OF RAIN ASSOCIATED WITH THE OUTER FRINGES OF SANDY
TO SHIFT NORTH ACROSS THE SANDHILLS AND COASTAL PLAIN DURING THE
LATE MORNING AND AFTERNOON HOURS...MAINTAINING IFR/MVFR CONDITIONS
THROUGH SUNSET AT KFAY AND KRWI. FURTHER WEST ACROSS THE PIEDMONT
TAF LOCATIONS (KRDU/KGSO/KINT)...LOW STRATUS IS EXPECTED TO LIFT AND
FOG WILL DISSIPATE DURING THE MID MORNING HOURS RESULTING IN
MVFR/OCCASIONAL VFR CONDITIONS. NORTH/NORTH-NORTHEAST WINDS AT
12-16KTS WITH GUSTS OF 20-28KTS ARE EXPECTED.
LOOKING FURTHER AHEAD...
ADVERSE AVIATION CONDITIONS ARE POSSIBLE THROUGH SUNDAY
NIGHT...ESPECIALLY ACROSS THE COASTAL PLAIN LOCATIONS AS THE WESTERN
FRINGE AND WRAP AROUND MOISTURE ASSOCIATED WITH SANDY THREATENS THE
AREA. ANOTHER ROUND OF ADVERSE AVIATION CONDITIONS IS POSSIBLE
MONDAY NIGHT AND TUESDAY...ESPECIALLY ACROSS NORTHERN PORTIONS OF
CENTRAL NC. TREND TOWARD FAIR WEATHER EXPECTED WEDNESDAY. -BLAES
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DJF
NEAR TERM...KC/BLS
SHORT TERM...WSS
LONG TERM...WSS
AVIATION...BLAES
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
451 AM EDT SAT OCT 27 2012
.SYNOPSIS...
A COLD FRONT OOZES THROUGH THE CENTRAL APPALACHIANS SATURDAY. SANDY
COMBINES WITH A STRONG UPPER LEVEL SYSTEM TO IMPACT THE AREA SUNDAY
THROUGH MUCH OF NEXT WEEK...WITH WIND AND PROLONGED PRECIPITATION.
&&
.NEAR TERM /THROUGH TONIGHT/...
EARLY THIS MORNING FINDS A S/W TROUGH OVER THE OHIO VALLEY DRIVING A
COLD FRONT THROUGH THE AREA...AND ADDITIONAL SHORT WAVE ENERGY
DIGGING INTO THE PLAINS BEHIND A L/R MIDWEST TROUGH...ALL WHILE
SANDY IS MOVING SLOWLY N...OUT E OF NORTHERN FL AND N OF THE BAHAMAS.
THE KEY TO THE NEXT 27 HOURS IS THE S/W ROTATION THROUGH THE L/R
TROUGH. THE OHIO VALLEY SHORT LIFTS THROUGH THE EASTERN GREAT LAKES
TODAY AND THEN INTO EASTERN CANADA TONIGHT. THE SURFACE COLD FRONT
NEARING THE WV MOUNTAINS EARLY THIS MORNING SLOWLY OOZES THROUGH
THERE TODAY...AND THEN ACTUALLY GETS ABSORBED INTO THE CIRCULATION
OF SANDY LATER TODAY AND TONIGHT.
THE PRECIPITATION BEHIND THE COLD FRONT MAKES VERY SLOW EWD
PROGRESS...BARELY MAKING IT ACROSS THE OHIO RIVER TODAY. COVERAGE
SHOULD ACTUALLY DIMINISH IN PLACE AS THE FORCING LIFTS OUT THIS
AFTERNOON AND EVENING. OVERNIGHT TONIGHT...THE ADDITIONAL S/W
ENERGY ON THE BACK SIDE OF THE L/R...ESSENTIALLY A SPEED
MAX...CARVES OUT A SHARP...NEGATIVE TILT S/W AS IT ROUNDS THE BASE
OF THE L/R. ITS FORCING INCREASES RAINFALL COVERAGE OVERNIGHT IN A
BAND EITHER SIDE OF THE OHIO RIVER BENEATH A DEFORMATION AXIS
FORMING THERE.
ALSO ADDED DRIZZLE TO THE FORECAST WITH THE PREPONDERANCE OF LOW
LEVEL MOISTURE AND UPSLOPE CONVERGENT LOW LEVEL FLOW.
BLENDED IN HRRR EARLY ON...THEN NAM12 TEMPERATURES AND DEW POINTS TO
BETTER DEPICT THE EVOLUTION OF THE RESPECTIVE GRADIENTS OVER THE
AREA ASSOCIATED WITH THE FRONT MOVING TO THE E. GENERALLY A LITTLE
HIGHER THAN PREVIOUS.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY/...
00Z MODELS IN FAIRLY GOOD AGREEMENT WITH A STALLED AREA OF PRECIP
ALONG THE OHIO RIVER TO START THE SHORT TERM...AND THEN SLOWLY
MERGE THIS INTO THE OVERALL PRECIP SHIELD OF SANDY SUNDAY NIGHT
INTO MONDAY...WITH THE HIGHEST POPS SLIDING INTO THE EASTERN CWA AS
SANDY MAKES LANDFALL. STILL SOME DIFFERENCES IN EXACT LAND
FALL...WITH GFS/NAM SHOWING A CENTRAL/NORTHERN NJ ENTRY POINT...AND
THE ECMWF A BIT SOUTH IN DELMARVA.
NO MATTER THE EXACT LANDFALL...CONFIDENCE CONTINUES TO INCREASE IN A
HIGH PRECIP/HIGH WIND FORECAST...WITH THE GREATEST IMPACTS IN THE
HIGHER TERRAIN WHERE ACCUMULATING UPSLOPE-ENHANCED SNOW AND 40+ KT
WIND GUSTS COULD CREATE QUITE THE WINTER STORM WITH DRIFTING AND LOW
VISIBILITY IN BLOWING SNOW.
INHERITED THE WINTER STORM WATCH...AND AFTER REWORKING THE SNOW
GRIDS DID NOT FEEL CHANGES TO THE HEADLINE WHERE NEEDED AT THIS
TIME. TEMPERATURE ADVECTION...AND ULTIMATELY WHERE THE BEST TEMP
PROFILE FOR SNOW SETS UP...IS KIND OF TRICKY WITH THIS WRAPPED UP
SYSTEM. WILL LIKELY SEE WAA COMING IN ON NORTH WINDS FOR A
TIME...AND THEN POSSIBLY SOME CAA COMING WITH MORE SOUTHWESTERLY
WINDS TOWARDS THE END OF THE SHORT TERM. AM NOT REAL CONFIDENT THAT
THE MODELS HAVE A GOOD HANDLE ON JUST WHERE THE COLDEST MIDLEVEL AIR
WILL BE...OR EVEN HOW COLD IT WILL BE. 00Z GFS/NAM AGREE ON -4C TO
-5C 850 TEMPS BY MONDAY NIGHT...WHILE 00Z ECMWF IS WARMER WITH -1C
TO -2C. THE GFS/NAM WOULD HINT TOWARDS SNOW ACROSS MOST OF THE CWA
BY MONDAY NIGHT...WHILE THE EURO KEEPS IT MORE IN THE MOUNTAINS.
WENT WITH A COMPROMISE...WITH ACCUMULATING SNOW IN THE
MOUNTAINS...AND A RAIN/SNOW MIX CLOSER TO THE OHIO RIVER. EVEN WITH
SOME FLAKES FALLING ACROSS THE LOWLANDS...THINK WITH THE WARM GROUND
ACCUMULATIONS WILL BE TOUGH TO COME BY.
&&
.LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/...
PRIMARY FORECAST CONCERN FOR THIS PERIOD OBVIOUSLY CONTINUES TO
REVOLVE AROUND SANDY/S TRACK AND POTENTIAL IMPACTS FOR THE NORTHEAST
CONUS IN GENERAL...AND SPECIFICALLY POTENTIAL IMPACTS FOR OUR
FORECAST AREA. WITH REGARD TO WHERE SANDY/S LANDFALL...NHC/S TRACK
HAS SHIFTED SOUTHWARD AND NOW BRINGS THE CENTER ASHORE OVER THE
DELMARVA PENINSULA. WITH THE STORM STILL BEING FOUR DAYS AWAY
SIGNIFICANT DIFFERENCES OBVIOUSLY STILL EXIST WITH HOW EXT GUIDANCE
HANDLES SANDY/S TRACK. TO SOME EXTENT EVEN GREATER UNCERTAINTY
EXISTS WITH HOW SANDY/S POST-TROPICAL EVOLUTION TAKES PLACE WITH
STRONG COLD AIR INTRUSION OUT OF THE NORTHWEST...AND THIS WILL HAVE
MAJOR RAMIFICATIONS AS TO THE SNOW/ICE IMPACTS OUR FORECAST AREA
EXPERIENCES AND TO A LESSER EXTENT WIND SPEEDS.
BREAKING DOWN THE SIG DIFFERENCES BETWEEN THE EXT MODELS AND
STARTING WITH THE 00Z EC...SANDY/S CENTER COMES ASHORE OVER DELMARVA
AREA MONDAY AFTERNOON AND SLOWLY MOVES TOWARDS THE EASTERN PANHANDLE
WV AREA BY 12Z TUE. THE SFC CENTER FILLS RAPIDLY BY TUESDAY MORNING
AS WELL WITH A SFC PRESS OF 982MB BY SAME TIME WITH WARM ADVECTION
WRAPPING AROUND THE BACKSIDE. THIS SCENARIO WOULD LIKELY MEAN MUCH
HIGHER PRECIP AMOUNTS FOR THE OVERALL AREA BUT WOULD ALSO MEAN A
LESSER LIKELIHOOD OF ACCUM SNOWFALL FOR LOWER ELEVATIONS AS THE
540DAM THICKNESS HEIGHT LINE REMAINS GENERALLY ALONG AND WEST OF OUR
FORECAST AREA. HIGH RAINFALL AMOUNTS BECOME THE BIGGER ISSUE WITH
THIS SCENARIO FOR LOWLANDS WITH A GENERAL 2-4 INCHES OF QPF DEPICTED
WITH HIGHER AMOUNTS CERTAINLY POSSIBLE.
MEANWHILE THE 12Z GFS CONTINUES TO BRING SANDY/S CENTER ASHORE NEAR
NYC TUES AFTERNOON WITH A SW RETROGRADE NEAR PHILLY BY TUE
EVE...BEFORE KICKING IT OUT TO THE N/NW WEDNESDAY. THIS SCENARIO
BRINGS A LONGER WIND EVENT CONTINUING WELL INTO TUE WITH THE SFC LOW
FARTHER AWAY. THIS SCENARIO ALSO ALLOWS COLDER AIR INTO THE
AREA...WITH THE 540DAM LINE COMPLETELY ENCOMPASSING AND WELL SOUTH
OF THE FORECAST AREA. THIS SCENARIO WOULD SPELL SNOWFALL FOR LOWLAND
LOCATIONS AS WELL. EVEN SO...WITH WARM SFC TEMPS FROM A WEEK OF VERY
WARM WEATHER IT WOULD PROBABLY TAKE SOME TIME BEFORE SNOW BEGINS TO
ACCUM ON ROADWAYS.
WITH ALL THIS IN MIND...WILL SIDE THE FORECAST TOWARDS THE EC WHICH
IS MUCH CLOSER TO NHC/S CURRENT TRACK AND THUS WILL LEAN THE
EVOLUTION OF THE SYSTEM IN THIS DIRECTION AS WELL. EITHER
WAY...THOUGH THE BEGINNING OF THE EVENT IS STILL 2-3 DAYS OUT
CONFIDENCE IS GROWING WITH A SIGNIFICANT SNOWFALL EVENT FOR THE HIGH
COUNTRY...PARTICULARLY FOR THE HIGHEST LOCATIONS SUCH AS SNOWSHOE.
IN COORDINATION WITH THE SHORT TERM FORECASTER...WILL KEEP WINTER
STORM WATCH FOR THESE AREAS GOING THROUGH 00Z WED WITH THE LONG
DURATION POTENTIAL. ACROSS THE LOWLANDS AMOUNTS GENERALLY UNDER TWO
INCHES ARE EXPECTED FOR WV ZONES...WITH MUCH OF IT COMING DURING THE
OVERNIGHT HOURS WITH PRIMARILY RAIN DURING THE DAY. LITTLE SNOW
SHOULD ACCUMULATE ON ROAD SURFACES WITH SUCH VERY WARM TEMPS IN
PLACE THIS WEEK. HAVE ALSO LOWERED MAX TEMPS TUESDAY AND WEDNESDAY.
AGAIN...STILL A GOOD DEAL OF UNCERTAINTY WITH THE FINAL TRACK AND
ANY SHIFT NORTH OR SOUTH COULD MAKE SUBSTANTIAL DIFFERENCES IN
RAIN/SNOW AMOUNTS RECEIVED AND WHERE...SNOW ACCUMULATIONS...ALONG
WITH WINDS.
&&
.AVIATION /08Z SATURDAY THROUGH WEDNESDAY/...
MVFR CIGS OOZING E ACROSS AREA OVERNIGHT WILL THEN HANG AROUND
THROUGH THE BALANCE OF THE PERIOD...WITH IFR POSSIBLE. RAIN SHOWERS
SAT AND SAT EVENING WILL BRING MVFR VSBYS.
SURFACE FRONT WILL CROSS THE MOUNTAINS FIRST THING SAT
MORNING...WITH LIGHT SE FLOW AHEAD OF IT. OTHERWISE LIGHT N TO NW
SURFACE FLOW BEHIND THE FRONT WILL FRESHEN A BIT SAT AND THEN REMAIN
NEAR 10 KTS MOST LOCALES SAT NT. FRONT ALOFT WILL ENTER WESTERN WV
SAT AFTERNOON AND THEN STALL THERE. LIGHT N TO NE FLOW BEHIND THE
FRONT WILL BE MODERATE N TO NE SAT AFTERNOON AND NT. AHEAD OF THE
FRONT ALOFT...LIGHT SE FLOW OVERNIGHT WILL BECOME LIGHT S SAT AND
THEN LIGHT E TO NE LATE SAT AND SAT NT.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z SUNDAY...
FORECAST CONFIDENCE: HIGH.
ALTERNATE SCENARIOS: IFR MATERIALIZATION IN QUESTION SAT.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
DATE SAT 10/27/12
UTC 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17
EDT 1HRLY 02 03 04 05 06 07 08 09 10 11 12 13
CRW CONSISTENCY H H M M M M M H H H H H
HTS CONSISTENCY L H H H H H H H H H H H
BKW CONSISTENCY L L L L L L L L H H H H
EKN CONSISTENCY H H M M M M H H H H H H
PKB CONSISTENCY L H H H H H H H H H H H
CKB CONSISTENCY H H M M M M M M H H H H
AFTER 06Z SUNDAY...
IFR POSSIBLE IN RAIN AND SNOW SHOWERS WITH REMNANTS OF SANDY EARLY
NEXT WEEK. RAIN WILL BE THE DOMINANT PRECIPITATION TYPE OVER THE
LOW TERRAIN...WITH SNOW PREDOMINANT ACROSS THE HIGHER TERRAIN. THE
PRECIPITATION WILL TEND TO BE MORE IN THE FORM OF RAIN DURING THE
DAY...WHEN MOST OF WHAT IS SNOW IS WET SNOW. FOR THE OTHERWISE RAIN
DOMINATED LOWLANDS...WET SNOW IS POSSIBLE AT NT.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...WINTER STORM WATCH FROM LATE SUNDAY NIGHT THROUGH TUESDAY
EVENING FOR WVZ038-046-047.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...TRM
NEAR TERM...TRM
SHORT TERM...MZ
LONG TERM...50
AVIATION...TRM
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
218 AM EDT SAT OCT 27 2012
.SYNOPSIS...
A COLD FRONT WILL MOVE INTO THE REGION BEFORE DISSIPATING ON
SATURDAY. TROPICAL CYCLONE SANDY WILL MOVE NORTH ACROSS THE OFFSHORE
ATLANTIC WATERS INTO MONDAY DEVELOPING INTO A POWERFUL NOR-EASTER.
THIS WILL RESULT IN UNSEASONABLY CHILLY AND WINDY CONDITIONS OVER
THE AREA MONDAY THROUGH WEDNESDAY.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 215 AM...I WILL ISSUE A QUICK UPDATE TO INCREASE SKY COVER
THIS MORNING. CLOUDS SHOULD BEGIN TO ERODE BY MID DAY...RESULTING IN
MARGINAL WIND GUSTS TO DEVELOP ACROSS THE CWA. I WILL ADJUST WIND
TIMING AND STRENGTH.
AS OF 1030 PM EDT...REMOVED PRECIP CHANCES IN THE MTNS FOR THE
OVERNIGHT HOURS. 23Z HRRR RUN SHOWS THE LIGHT PRECIP BEHIND THE
FRONT ACROSS MIDDLE TN BUT KEEPS THE SHOWERS THERE...WITH NO
DEVELOPMENT SEEN AHEAD OF IT. 00Z NAM SUGGESTS THE FRONT WILL NOT
MAKE IT TO THE MTNS UNTIL LATE MORNING SO POP TREND WAS SLOWED
GREATLY.
AS OF 915 PM EDT...WILL MAINTAIN PREVIOUS FCST FOR LOW TEMPS TONIGHT
AS THERE WAS LITTLE CHANGE BETWEEN 12Z AND 18Z RUNS. MONITORING LOW
STRATUS AND SHOWERS BOTH NEAR THE COLD FRONT /MIDDLE TN/ AND IN THE
MOIST REGION UPSTREAM IN EASTERLY FLOW /ERN NC/. THE ONGOING LIGHT
SHOWERS IN THE VICINITY OF RDU WOULD REACH THE NC PIEDMONT AROUND
04Z IF THEY HOLD TOGETHER. MOISTURE DOES KEEP INCREASING AND THE
STEADY EASTERLY FLOW SHOULD CONTINUE SO THAT IS PLAUSIBLE. WILL
BRING UP THE ONSET TIME TO 04Z OVER DAVIE/ROWAN/CABARRUS...THOUGH IF
THE SHOWERS MAKE IT THERE IN THIS STATE THEY WILL PROBABLY ONLY GET
SPRINKLES.
AS OF 730 PM EDT...EASTERLY FLOW IN THE MIDLEVELS ALONG WITH
INCREASING MOISTURE IN THE LAYER WILL PROMOTE CLOUD AND PRECIP
DEVELOPMENT IN THE LATE OVERNIGHT HOURS OVER THE NC PIEDMONT. THE
BOUNDARY LAYER ALSO MOISTENS IN THAT AREA...ENABLING LOW STRATUS TO
ALSO FORM. AT THE PRESENT TIME POPS OVER THE PIEDMONT LOOK A LITTLE
TOO LOW AND SO THEY WILL BE INCREASED AND EXPANDED WESTWARD. ON
ANOTHER NOTE...COLD FRONT IS ADVANCING RATHER SLOWLY ACROSS THE TN
VALLEY AND MODEL DEPICTED FORCING IS NOT PARTICULARLY IMPRESSIVE
WITH IT OVER THE MOUNTAINS TONIGHT. WILL LOWER CHANCES TO SLIGHT
UNTIL MORNING.
AS OF 430 PM EDT...DELAYED ONSET OF PRECIP CHANCES IN THE MTNS BY A
COUPLE OF HOURS AND CONFIDENCE IS FAIRLY LOW THAT THE AREA WILL SEE
ANY SHOWERS AT ALL. CONVERGENCE LINE NEAR THE COLD FRONT OVER
CUMBERLAND PLATEAU IS PRODUCING A BAND OF CUMULUS BUT NO RADAR
RETURNS INDICATIVE OF PRECIP. MESO MODELS EITHER KEEP THE MTNS DRY
INTO THE EVENING OR SHOW DIURNALLY DRIVEN SHOWERS WHICH NOW SEEM
UNLIKELY GIVEN SATELLITE IMAGERY SHOWING THE CU OVER THE MTNS
FLATTENING OUT. UPDATED SKY TRENDS TO BETTER REPRESENT CIRRUS OVER
THE PIEDMONT...GENERALLY LEANING SUNNIER THE REMAINDER OF THE
AFTERNOON...THOUGH MAINTAINED INCREASING CLOUDS THIS EVENING.
AS OF 230 PM EDT...HURRICANE SANDY WILL MOVE NORTHWARD OFFSHORE OF
THE SE COASTLINE TONIGHT THROUGH SATURDAY...GRADUALLY STRENGTHENING
THE PRESSURE GRADIENT AND NRLY FLOW ACROSS THE REGION. MEANWHILE...A
BROAD TROUGH OF LOW PRESSURE EXTENDING SWD FROM A DEEPENING
MANITOBA/ONTARIO VORTEX WILL MAINTAIN A TROUGH AXIS W OF THE
APPALACHIANS THROUGH THE PERIOD. AN ASSOCIATED COLD FRONT CURRENTLY
STRETCHING FROM KJKL TO KCSV WILL MOVE SLOWLY EWD ACROSS EXTREME ERN
TN TONIGHT AND THEN STALL ACROSS THE SRN APPALACHIANS ON SAT.
AHEAD OF THE APPROACHING BOUNDARY...THE MODELS WRING OUT ISOLD TO
SCT SHOWERS IN THE SW MTNS IN CONVERGENT BL FLOW WITH SFC BASED CAPE
VALUES OF 300 TO 500 J/KG INTO THE EARLY EVENING THERE. THIS SEEMS
REASONABLE. THE FORCING REMAINS SOMEWHAT LIMITED ALONG THE STALLING
BOUNDARY LATE TONIGHT THROUGH SAT...BUT CONTINUED WEAK LLVL
CONVERGENCE COMBINED WITH IMPROVING UPPER DIVERGENCE SUPPORTS SCHC
TO CHC POPS IN AND NEAR THE MTNS. FARTHER E...LOW LEVEL NE FLOW
SHOULD ADVECT IN ANOTHER STRATUS LAYER FROM THE NE OVERNIGHT. AN
OUTER BAND OF TROPICAL RAIN SHOWERS AROUND THE SANDY CIRCULATION
COULD DEVELOP OVER THE CAROLINA PIEDMONT TONIGHT AND WRAP WWD TOWARD
THE INTERSTATE 77 CORRIDOR THROUGH SAT. WILL FEATURE MAINLY SCHC
POPS OVER ERN PIEDMONT SECTIONS ON SAT. THE PRES GRADIENT WILL ALSO
BE TIGHTEST ACROSS THE PIEDMONT...WITH GUSTY CONDITIONS LIKELY
DEVELOPING ALONG THE I-77 CORRIDOR SAT AFTN. THE DIURNAL TEMP RANGE
SHOULD BE SMALLER THAN IN RECENT DAYS...WITH WARM MINS TONIGHT...AND
COOLER MAXES SAT.
&&
.SHORT TERM /TONIGHT THROUGH TUESDAY/...
AS OF 245 PM FRIDAY...THE OPERATIONAL GUIDANCE CONTINUES TO AGREE ON
THE LARGE SCALE FEATURES...BUT CONTINUE TO DISAGREE ON THE EVENTUAL
TRACK OF SANDY AND ITS ASSOCIATED EXTRATROPICAL LOW. THE ENSEMBLE
MEANS HOWEVER...ARE IN MUCH BETTER AGREEMENT WITH EACH OTHER AND THE
OFFICIAL FORECAST TRACK FROM NHC/HPC. THE CURRENT FCST TRACK CURVES
THE CIRCULATION OFF THE CAROLINA COAST THEN INLAND NEAR THE DELAWARE
BAY TUE MORNING. WE WILL STILL SEE SOME EFFECTS FROM THIS STORM EVEN
THO IT REMAINS RELATIVELY FAR AWAY FROM OUR CWFA. THAT SAID...THE
COLD FRONT MOVING INTO THE WRN CWFA WILL PLAY A BIGGER PART IN
PRECIP CHANCES SAT NITE AND SUN. EXPECT SCT SHRA TO CONTINUE OVER
THE MTNS AND NC FOOTHILLS SAT EVENING...WITH ISOLATED SHRA
ELSEWHERE. THESE SHRA DIMINISH OVERNIGHT WITH THE BEST CHC
RETREATING TO THE TN BORDER BY SUN MORNING. SHRA WILL LINGER THERE
THRU THE DAY EVEN AS THE FRONT DISSIPATES IN THE LINGERING LOW LEVEL
MOISTURE...STRENGTHENING NWLY FLOW AND INCREASING FORCING AS SHORT
WAVE MOVES ACROSS THE AREA. SUNDAY WILL BE BREEZY ALL AREAS AS WELL.
SAT NITE WILL STILL BE WARM BEFORE THE COLD AIR MOVES IN WITH LOWS
UP TO 5 DEGREES ABOVE NORMAL. THE COLD AIR BEGINS MOVING IN SUN WITH
HIGHS 10 DEGREES BELOW NORMAL ACROSS THE MTNS AND A FEW DEGREES
BELOW ELSEWHERE.
COLD AIR RUSHES IN BEHIND THIS SYSTEM SUN NITE AND MON AS SANDY
BEGINS ITS TURN TO THE NW AND TRANSITIONS TO AN EXTRATROPICAL LOW.
LINGERING LOW LEVEL MOISTURE AND INCREASING CAA AND NWLY FLOW WILL
KEEP SCT SHRA ALONG THE TN BORDER SUN NITE THEN DIMINISHING COVERAGE
MONDAY. SOME OF THIS PRECIP WILL FALL AS SNOW...ESPECIALLY ABOVE
3500 FT...BUT SOME OF THE HIGHER VALLEYS COULD SEE SNOW AS WELL. TOO
EARLY TO SAY HOW MUCH ACCUMULATION COULD DEVELOP...BUT AN INCH OR
TWO IS POSSIBLE. THE WINDS WILL CONTINUE TO INCREASE ACROSS THE
CWFA...ESPECIALLY DURING THE DAY MONDAY WITH MIXING. GUSTS UP TO 45
MPH ARE POSSIBLE OVER THE MTNS...WITH 40 MPH ELSEWHERE. LOWS WILL BE
AROUND 5 DEGREES BELOW NORMAL WITH FREEZING TEMPS LIKELY ABOVE 3500
FT. HIGHS MONDAY 10 TO 15 DEGREES BELOW NORMAL.
LOW LEVEL MOISTURE BRIEFLY WANES MON NITE THEN RETURNS ACROSS THE TN
BORDER COUNTIES TUE. EXPECT RAIN/SNOW SHOWERS TO DIMINISH MON EVE
THEN RETURN FOR THE DAY TUE. WINDS DROP OFF A LITTLE MON NITE BUT
REMAIN BREEZY...THEN RETURN EVEN STRONGER ON TUE. TUE LOOKS TO BE
THE WINDIEST DAY WITH GUSTS LIKELY REACHING WIND ADV LEVELS OVER THE
MTNS WITH HIGH WIND WARNING GUSTS POSSIBLE. GUSTS COULD REACH 40 TO
45 MPH ELSEWHERE. WIDESPREAD FREEZE OVER THE MTNS STILL EXPECTED MON
NITE WITH LOW TO MID 30S ELSEWHERE...WITH FREEZE POSSIBLE INTO THE
NC FOOTHILLS. HIGHS TUE 15 TO 20 DEGREES BELOW NORMAL.
&&
.LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/...
AS OF 200 AM SATURDAY...THERE IS WAY TOO MUCH UNCERTAINTY ABOUT THE
EVENTUAL TRACK OF T.C. SANDY AND THE INTENSE RESULTANT EXTRATROPICAL
SYSTEM TO NAIL DOWN THE TUESDAY NIGHT AND WEDNESDAY PERIOD. IT/S
INTERESTING THAT SOME OF THE BEST FORCING AND HIGHEST DEEP LAYER
MOISTURE VALUES FOR THE EVENT ON THE 12 UTC ECWMF HAPPEN TUE NIGHT.
THE 00 UTC GFS ON THE OTHER HAND BRINGS MUCH DRIER AIR ACROSS THE
FORECAST AREA TUE AND TUE NIGHT...EFFECTIVELY ENDING ANY NW FLOW
SNOW CHANCES. THE 00 UTC CANADIAN IS LEANING THIS DIRECTION AS WELL.
FOR NOW I HAVEN/T UPPED POPS BEYOND THE DAYLIGHT PERIOD ON TUE.
WE/LL REALLY JUST HAVE TO WAIT TO SEE JUST HOW FAR SOUTHWEST THE
UPPER LOW DIGS AND IF THE MAJOR AXIS TAKES ON A NW TO SE ORIENTATION
LIKE THE GFS HAS. THERE WILL BE MORE THAN ENOUGH WEATHER TO DEAL
WITH BEFORE TUESDAY NIGHT.
WINDY CONDITIONS WILL CONTINUE OVER THE MOUNTAINS AND FOOTHILLS TUE
NIGHT AND ACROSS THE FA ON WEDNESDAY. THE SFC LOW WILL HAVE FILLED
QUITE A BIT BY WED AFTERNOON...AND WE SHOULD/T BE LOOKING AT
ANYTHING MORE THAN LOW END WINDY CONDITIONS THE WAY IT LOOKS NOW.
THICKNESSES REMAIN LOW WED NIGHT AND THURSDAY NIGHT. WITH THE LOW
PULLING AWAY...WINDS WILL DECOUPLE OVERNIGHT IN MAY
AREAS...INCREASING THE RISK FOR FROST OR EVEN A FREEZE ACROSS A GOOD
BIT OF THE FOOTHILLS AND PIEDMONT BOTH NIGHTS. MY LOW TEMPS DON/T
QUITE REFLECT A FREEZE AT THIS POINT...BUT IT/S A DISTINCT
POSSIBILITY. BY THIS TIME THE GROWING SEASON SHOULD BE OVER ACROSS
THE MTNS AND MORE WESTERLY FOOTHILLS LOCATIONS.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
AT KCLT...CIRRUS SHIELD ASSOCIATED WITH HURRICANE SANDY HAS OBSCURED
THE VIEW OF STRATOCU ACROSS THE NC PIEDMONT. HOWEVER...RECENT SFC
OBSERVATIONS NEAR THE TRIAD INDICATE THAT CEILINGS RANGED FROM IFR
TO LMVFR AT 5Z. THESE LOW CLOUDS LINE UP WELL WITH THE NAM12
CONDENSATION PRESSURE DEFICITS OF 8 TO 15 MBS. I WILL USE THE NAM12
SFC CONDENSATION PRESSURE DEFICITS FOR TIMING AND PLACEMENT OF
RESTRICTIVE CEILINGS THIS MORNING. IT APPEARS THAT MVFR CEILINGS ARE
LIKELY BY 8Z AND WILL CONTINUE TO LOWER TO IFR DURING THE PRE DAWN
HOURS AND MAY REMAIN IFR UNTIL MID MORNING. ONCE IFR CLOUDS DISSIPATE
AFTER SUNRISE...MARGINAL GUSTY NNE WINDS SHOULD DEVELOP AND REMAIN
INTO THE AFTERNOON HOURS WITH MVFR CEILINGS. BY 19Z...RESTRICTIVE
CEILINGS SHOULD DISSIPATE AND LOW VFR CU SHOULD DEVELOP AND REMAIN
UNTIL SUNSET.
ELSEWHERE...THE PRIMARY CHALLENGE EARLY THIS MORNING WILL BE THE
TIMING AND PLACEMENT OF MVFR TO IFR CEILINGS. AT 5Z...KHKY WAS
ALREADY OBSERVING BKN018. PLAN VIEW OF THE NAM12 CONDENSATION
PRESSURE DEFICITS INDICATE THAT LOW VALUES WILL EXPAND NE TO SW
ACROSS THE WESTERN CAROLINAS THROUGH 12Z. AREAS ALONG THE TN BORDER
WILL SEE DEVELOPING UPSLOPE FLOW AROUND SUNRISE...LIKELY SUPPORTING
A EXPANDING AREA OF LOW CLOUDS. ALL TERMINALS SHOULD SEE MVFR
CEILINGS DEVELOPING BY SUNRISE...WITH KAVL IFR BY 12Z. CONDITIONS
WILL GRADUALLY IMPROVE DURING THE AM...RETURNING TO VFR BY MID DAY.
GUSTY NORTH WINDS SHOULD DEVELOP DURING THE EARLY AFTERNOON AND
REMAIN THROUGH SUNSET. CONDITIONS SHOULD REMAIN VFR THROUGH THE REST
OF THE TAF PERIOD EAST OF THE MTNS. UPSLOPE CLOUDS MAY RETURN KAVL
TO MVFR BY 1Z AND LINGER THROUGH THE END OF THE TAF.
OUTLOOK...LOW LEVEL MOISTURE SHOULD GENERATE RESTRICTIVE CIGS AGAIN
INTO SUNDAY. A VIGOROUS PUSH OF COLD AIR BEHIND HURRICANE SANDY WILL
ARRIVE EARLY NEXT WEEK...CREATING VERY WINDY CONDITIONS ACROSS THE
REGION...AND POSSIBLE MOUNTAIN CEILING RESTRICTIONS IN THE NW FLOW.
AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)...
WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...CSH
NEAR TERM...NED/WIMBERLEY
SHORT TERM...RWH
LONG TERM...MCAVOY
AVIATION...NED
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
231 AM CDT SAT OCT 27 2012
.SHORT TERM...TODAY THROUGH MONDAY NIGHT
231 AM CDT SAT OCT 27 2012
MAIN FORECAST CONCERNS ARE ON CLOUDS AND TEMPERATURES THROUGHOUT DUE
TO LACK OF PRECIPITATION FORCING MECHANISMS.
CURRENTLY AS OF 07Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
LOOKS VERY SIMILAR TO 24 HOURS AGO WITH RIDGING OVER THE EASTERN
PACIFIC...TROUGHING OVER THE WESTERN TWO THIRDS OF CANADA INTO THE
SOUTHERN PLAINS...RIDGING OVER NEWFOUNDLAND AND TROPICAL STORM SANDY
SITTING JUST NORTH OF THE NORTHWEST BAHAMAS. MAIN SHORTWAVE OF NOTE
WAS OVER SOUTHERN BRITISH COLUMBIA WITH A 130 KT JET STREAK NEAR
225MB IN EASTERN WASHINGTON STATE. A STREAM OF CIRRUS EXTENDED
DOWNSTREAM FROM THIS SHORTWAVE INTO MONTANA AND THE WESTERN DAKOTAS.
FARTHER EAST INTO THE FORECAST AREA...A BROKEN FIELD OF
STRATOCUMULUS COVERED MUCH OF THE UPPER MISSISSIPPI RIVER VALLEY
REGION. THESE CLOUDS WERE REPRESENTED WELL ON THE 00Z MPX SOUNDING
BY YET ANOTHER MOIST LAYER BETWEEN 750-800MB. AIRMASS REMAINS COOL
OVER THE FORECAST AREA WITH 00Z SOUNDINGS SHOWING 850MB TEMPS AROUND
-7C. HOWEVER...THE CLOUDS AND A LIGHT WESTERLY BREEZE NORTH OF HIGH
PRESSURE IN WESTERN IOWA HAVE HELPED TO LIMIT THE TEMPERATURE FALL
TOO MUCH THUS FAR. TEMPERATURES SO FAR HAVE FALLEN INTO THE UPPER
20S TO MID 30S.
TODAY THROUGH SUNDAY...FOCUS FOR OUR AREA IS ON THAT SHORTWAVE IN
SOUTHERN BRITISH COLUMBIA. MODELS ARE IN GOOD AGREEMENT DROPPING IT
DOWN INTO THE BASE OF THE UPPER TROUGH...REACHING FAR WESTERN
NEBRASKA BY 00Z SUNDAY...THE MEMPHIS TN AREA BY 12Z SUNDAY AND THEN
PUSHING EAST TO THE GREAT SMOKY MOUNTAINS AREA BY 00Z MONDAY. AS
THIS SHORTWAVE DIVES SOUTHEAST...EXPECT THE MASS OF CIRRUS ENTERING
THE DAKOTAS TO SPREAD INTO THE FORECAST AREA THIS AFTERNOON AND
EVENING. THUS...EVEN IF THE CURRENT STRATOCUMULUS CONTINUES TO BREAK
UP OR DISSIPATE...THE CLEARING LOOKS TO BE TEMPORARY. THE CIRRUS
APPEARS TO HOLD ON THROUGH MUCH OF TONIGHT...THEN THERE ARE
SUGGESTIONS OF A DECAYING MID CLOUD DECK ASSOCIATED WITH THE
SHORTWAVE MOVING INTO THE AREA FROM THE WEST ON SUNDAY. PLENTY OF
LOW LEVEL DRY AIR AND LACK OF FORCING WILL KEEP THE FORECAST AREA
DRY. HOWEVER...THE CLOUDS ARE LIKELY TO MAKE AN IMPACT ON
TEMPERATURE FORECASTS. BEING IN UPPER TROUGHING AND THE LOW SUN
ANGLE THIS TIME OF YEAR...THE 850MB TEMPS AND GENERAL AIRMASS ARE
GOING TO HAVE A TOUGH TIME WARMING. IN FACT...THE READINGS CHANGE
VERY LITTLE...CLIMBING FROM -6 TO -8C TODAY TO -4 TO -6C ON SUNDAY.
WITH CLOUDS AROUND...ANTICIPATING HIGHS TO STAY STUCK IN THE LOWER
TO MID 40S. THE CIRRUS DECK AND INCOMING MID CLOUDS SHOULD HELP TO
KEEP TEMPERATURES UP TONIGHT...IN THE UPPER 20S TO LOW 30S.
SUNDAY NIGHT THROUGH MONDAY NIGHT...MUCH OF THE ACTION IS EXPECTED
IN THE MID-ATLANTIC AND NORTHEAST U.S. DURING THIS PERIOD...IN
RESPONSE TO INTERACTION AND PHASING OF SANDY WITH THE CURRENT
BRITISH COLUMBIA SHORTWAVE...RELEASE OF LATENT HEAT AND A COUPLING
OF SUBTROPICAL AND POLAR JETS. THE NET RESULT BY 12Z TUESDAY FROM
ALL MODELS IS A DEEP UPPER TROUGH ENCOMPASSING MUCH OF THE EASTERN
U.S. WITH A DEEP POST-TROPICAL SANDY SITUATED IN OR NEAR PENNSYLVANIA.
MEANWHILE...UPPER RIDGING THAT HAS BEEN OVER THE EAST PACIFIC
MODELS HAVE BUILDING ACROSS THE WESTERN U.S. AND INTO THE WESTERN
PLAINS. THIS SETUP EFFECTIVELY BLOCKS ANY PRECIPITATION FROM
ENTERING THE PICTURE FOR OUR AREA. IN FACT...HIGH PRESSURE SHOULD
DOMINATE AT THE SURFACE THROUGH MUCH OF THE TIME PERIOD.
TEMPERATURES LOOK TO STAY COOL DUE TO 850MB TEMPS STILL ONLY
WARMING SLOWLY TO -1 TO -4C ON MONDAY. CLOUD COVER WISE...THERE
ARE HINTS OF SOME WARM ADVECTION MID CLOUDS COMING INTO WESTERN
SECTIONS OF THE AREA ON MONDAY...BUT THEN THESE GET SHUNTED
SOUTHWEST BY SUBSIDENCE ON THE BACK SIDE OF THE DEEP EASTERN
TROUGH.
.LONG TERM...TUESDAY THROUGH FRIDAY NIGHT
231 AM CDT SAT OCT 27 2012
FOCUS FOR THE EARLY PORTION OF THE LONG TERM PERIOD IS THE DEEP
EASTERN U.S. UPPER TROUGH AND POST-TROPICAL SANDY INSIDE OF THE
TROUGH. 27.00Z ECMWF/GFS/CANADIAN/UKMET AND GFS ENSEMBLES ARE IN
VERY GOOD AGREEMENT THAT THE DEEP UPPER TROUGH WILL BE BLOCKED
BETWEEN RIDGING OVER THE WESTERN U.S....STRONG UPPER RIDGING NEAR
NEWFOUNDLAND AND PERHAPS EVEN RIDGING CONNECTING THESE TWO. AS
SUCH...THE MODELS TAKE AWHILE BEFORE LIFTING THE EASTERN TROUGH OUT.
IT MAY NOT BE UNTIL SOMETIME THURSDAY NIGHT OR FRIDAY BEFORE THE
EJECTION OCCURS. WITH THE EASTERN TROUGH BLOCKED FROM MOVING
MUCH...THE FORECAST AREA STAYS ON THE SUBSIDENT SIDE THROUGH AT
LEAST THURSDAY...MOSTLY PREVENTING PRECIPITATION. ONE CONCERN WOULD
BE DEFORMATION PRECIPITATION ASSOCIATED WITH POST-TROPICAL SANDY
RETROGRADING SLOLWY WESTWARD TOWARDS THE AREA TUESDAY INTO
WEDNESDAY. HOWEVER...MOST MODELS SUGGESTS THIS DEFORMATION BAND
WILL STAY EAST OF THE AREA...PERHAPS MAKING IT AS FAR WEST AS
EASTERN WISCONSIN. LOOKS LIKE WE WILL SEE A NORTHERLY BREEZE
INCREASE FOR TUESDAY AND PERHAPS WEDNESDAY TOO...PARTICULARLY
ACROSS WISCONSIN. FOR FRIDAY...GOOD MODEL CONSENSUS EXISTS FOR
SUBTROPICAL UPPER RIDGING TO CROSS THE CENTRAL AND SOUTHERN PLAINS
AHEAD OF A TROUGH CROSSING COLORADO. ANY WARM ADVECTION
PRECIPITATION ASSOCIATED WITH THE RIDGE LOOKS TO STAY TO THE SOUTH
AT THE PRESENT TIME...THOUGH AN INCREASE IN MID/HIGH CLOUDS SHOULD
OCCUR.
TEMPERATURES WILL GRADUALLY WARM THROUGH THE LONG TERM PERIOD...
ESPECIALLY TOWARDS THE END OF THE WEEK AS THE EASTERN UPPER TROUGH
LIFTS OUT. BY THURSDAY...READINGS SHOULD BE BACK TO NEAR NORMAL.
&&
.AVIATION...THROUGH 06Z SUNDAY
1129 PM CDT FRI OCT 26 2012
VFR CONDITIONS EXPECTED INTO SATURDAY NIGHT AS A RIDGE OF HIGH
PRESSURE TRACKS INTO THE REGION. WINDS WILL BE LIGHT THROUGHOUT
WITH CLOUD COVER THE MAIN CHALLENGE. BROKEN TO OVERCAST 4 TO 6KFT
STRATOCUMULUS IS IN PLACE THROUGH MUCH OF THE UPPER MISSISSIPPI
VALLEY WITH SOME OF THE BREAKS IN THE CLOUD COVER BECOMING LARGER
TO THE WEST OF THE TAF SITES. AS THE RIDGE MOVES IN SATURDAY
MORNING...EXPECT FOR THE LOW TO MID LEVEL CLOUD COVER TO CONTINUE
TO DISSIPATE WITH IT BECOMING EVEN PATCHIER BY AFTERNOON. THE NEXT
SYSTEM WILL BE MOVING ACROSS THE DAKOTAS TOMORROW EVENING WITH
HIGH LEVEL CLOUD COVER INCREASING FROM THE WEST.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
231 AM CDT SAT OCT 27 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...HALBACH
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
1010 AM EDT Sat Oct 27 2012
.NEAR TERM [Today and Tonight]...
Updated at: 1005am
Overall, the forecast for the next 12-18 hours appears to be in
good shape and very few changes were made this morning. The main
change was to increase the sky cover a bit. In the far western
part of our area, some low stratus had developed behind an
advancing cold front, and that front is becoming increasingly ill-
defined. Meanwhile, the western periphery of the cirrus shield
from Hurricane Sandy continued to be situated over most of the
rest of the area. The HRRR has the best handle on the current
extent of the high-level clouds and it hardly erodes the western
edge through the day. Despite that, most of the cirrus should be
at least semi-transparent and most of the area should see some
filtered sunshine. High temperatures should be very near normal
values. The breezy northwest flow is not expected to reach levels
that would prompt any advisories today. Most gusts should peak in
the 20-25mph range.
&&
.SHORT TERM [Sunday Through Monday]...
Both day and nighttime temps will continue to fall as the CAA
becomes even stronger, with Highs on Sunday ranging from the upper
60s NW to the lower to middle 70s elsewhere, and down to the lower
to middle 60s CWA wide on Monday. Low temps on Monday morning are
expected to drop into upper 30s across the NW 1/3 of the area,
with lower to middle 40s elsewhere. The unusually low Max temps on
Monday will set the stage for the coldest night of the season thus
far on Monday night, with some inland areas bottoming out into the
middle to upper 30s. Also, daytime winds will continue to remain
elevated out of the NW for both Sunday and Monday, with sustained
speeds generally 10-15 mph on Sun., and back to 15-20 mph on Mon.
&&
.LONG TERM [Monday Night through Friday]...
A chilly airmass is expected to dominate the first half of the
week as high pressure builds into the local area with
northwesterly flow behind the massive east coast low. The 27/00z
GFS trended slightly cooler and is now forecasting lows in the mid
to upper 30s on Monday night across the area. Much will depend on
the evolution of the large storm along the east coast. The 27/12z
ECMWF is not quite as bullish as the newer GFS with the cold push
into the local area. The official forecast went for a compromise
for now with upper 30s to lower 40s across the area for Monday
night. A gradual warming trend is expected for the middle and
latter part of the week as the airmass modifies. The GFS also
brings a weak shortwave through the area on Thursday with
scattered showers across the coastal waters and the southeast big
bend, but the old Euro run had nothing and the official forecast
will wait for a little more consistency before introducing any
mention of showers into the forecast.
&&
.AVIATION [through 12z Sunday]...
Mainly VFR conditions are expected through the period, although
some low clouds behind an approaching cold front may provide a few
hours of MVFR conditions around KDHN and KECP during the mid-
morning hours. Gusty northwest winds are expected in the wake of
the front with gusts around 20 knots, diminishing after sunset.
&&
.MARINE...
With the tight pressure gradient between Sandy (which should be
well to our NE near the Mid-Atlantic Coast by Monday afternoon),
and the cold Surface High pressure ridge to our Northwest expected
to tighten further and then remain steady into the beginning of
next week, decided to extend the Small Craft Advisory until Monday
evening. This will result in a fairly long period of rough
maritime conditions, with sustained northwest winds of 20 to 25
knots, with occasional gusts above 30 knots, continuing through at
least Monday. Seas are expected to peak into the 5 to 7 foot range
nearshore and 6 to 8 feet offshore. Both winds and seas should
subside significantly by the middle of next week.
&&
.FIRE WEATHER...
Drier conditions will begin to move into the region today as a
cold front pass through the area. Relative humidity values are
forecast to stay above critical levels this afternoon, but even
drier air is expected for Sunday with conditions approaching red
flag criteria across a portion of northwest Florida with gusty
winds and marginally low RH. The RH looks too marginal for a watch
at this time in our area on Sunday afternoon, but if the RH
forecast decreases, then a watch or warning may be needed later.
Red flag conditions will become more likely and widespread on
Monday and Tuesday with much lower RH values expected.
&&
.HYDROLOGY...
With little or no rainfall in the fcst through much of next week,
there are no hydrological concerns or significant river rises
expected across the area.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 81 52 73 44 65 / 10 0 0 0 0
Panama City 78 52 72 45 66 / 10 0 0 0 0
Dothan 75 47 69 40 63 / 10 0 0 0 0
Albany 79 51 71 41 65 / 10 0 0 0 0
Valdosta 78 54 73 43 65 / 10 0 0 0 0
Cross City 80 55 76 44 67 / 10 0 0 0 0
Apalachicola 79 54 72 49 67 / 10 0 0 0 0
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AL...None.
GM...SMALL CRAFT ADVISORY until 8 PM EDT Monday for all of the
coastal waters.
&&
$$
NEAR TERM...Lamers
SHORT TERM...Gould
LONG TERM...DVD
AVIATION...DVD
MARINE...Gould
FIRE WEATHER...DVD
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
615 AM EDT SAT OCT 27 2012
.SYNOPSIS...
TROPICAL SYSTEM SANDY WILL MOVE NORTHWARD OFF THE ATLANTIC COAST
THROUGH SUNDAY. THE PRESSURE GRADIENT ASSOCIATED WITH THE SYSTEM
WILL RESULT IN BREEZY CONDITIONS IN THE FORECAST AREA. MOST OF THE
RAIN ASSOCIATED WITH SANDY WILL REMAIN EAST OF THE FORECAST AREA.
AN APPROACHING COLD FRONT WILL MOVE THROUGH THE AREA SUNDAY. THE
COLDEST AIR OF THE SEASON SO FAR WILL FOLLOW THIS FRONT.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE MODELS ARE CONSISTENT KEEPING DEEP MOISTURE EAST OF THE
FORECAST AREA TODAY. MAINTAINED JUST CHANCE POPS IN THE EAST PART
ASSOCIATED WITH MOISTURE THAT MAY WRAP INTO THE AREA. MODEL TIME-
HEIGHT DISPLAYS AND MIXING SUPPORTS FREQUENT GUSTS NEAR 25 KNOTS.
WE HAVE ISSUED A LAKE WIND ADVISORY. IT WILL BE COOLER TODAY
COMPARED TO YESTERDAY MAINLY BECAUSE OF CLOUDINESS. THE
TEMPERATURE GUIDANCE WAS CLOSE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/...
THE NAM AND GFS CONTINUE TO SHOW DEEP MOISTURE REMAINING NORTHEAST
OF THE FORECAST AREA AS SANDY MOVES NORTH-NORTHEASTWARD. THE COLD
FRONT SUNDAY STILL APPEARS DRY BECAUSE OF A LACK OF SIGNIFICANT
CONVERGENCE. THE PRESSURE GRADIENT WILL CONTINUE TO SUPPORT BREEZY
CONDITIONS AND WE HAVE MAINTAINED THE LAKE WIND ADVISORY. USED THE
GUIDANCE CONSENSUS FOR THE TEMPERATURE FORECAST.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
STRONG LOW PRESSURE IN THE MIDDLE ATLANTIC AND NORTHEAST STATES
AND RIDGING IN THE MIDDLE OF THE NATION WILL MAINTAIN NORTHWEST
FLOW INTO THE FORECAST AREA DURING THE EXTENDED PERIOD. IT WILL BE
A DRY AND COOL PERIOD. THE GFS ENSEMBLE MEANS SUPPORT LOWS IN THE
30S.
&&
.AVIATION /10Z SATURDAY THROUGH WEDNESDAY/...
SURFACE HIGH PRESSURE TO OUR NE...WITH TROPICAL SYSTEM SANDY WELL
TO OUR SOUTHEAST JUST NORTH OF THE BAHAMAS WILL PRODUCE A STEADY N
WIND ACROSS MUCH OF THE CWA BECAUSE OF THE PRESSURE GRADIENT
BETWEEN THE TWO SYSTEMS. SATELLITE LOOP SHOWS PLENTY OF HIGH
CLOUDINESS ACROSS THE ENTIRE CWA TONIGHT. SATELLITE/OBS ALSO SHOWS
THE SLOW MOVING COLD FRONT TO OUR WEST ON THE WEST SIDE OF THE
APPALACHIANS. SANDY IS FORECAST TO MOVE TO THE N AND NE FOR THE
REMAINDER OF TONIGHT INTO SATURDAY. THE BULK OF THE ASSOCIATED
MOISTURE AND PRECIPITATION ACTIVITY WILL BE STAYING EAST OF THE
TAF SITES. GUIDANCE IN AGREEMENT INDICATING LOWER CLOUDINESS FOR
MUCH OF OUR CWA AFTER MIDNIGHT TOWARD MORNING. LATEST SATELLITE
AND SURFACE OBS INDICATE LOWER CLOUDS CURRENTLY ACROSS PORTIONS OF
CENTRAL AND E NC...WITH MAINLY MVFR CIGS. LATEST RAP BRINGS LOWER
CLOUDS SW INTO OUR CWA LATE TONIGHT UNDER A N/NE LOW LEVEL FLOW.
UNCERTAINTY WITH REGARDS TO WHETHER CIGS WILL BE MVFR OR IFR. FOR
NOW...WILL MAINTAIN LOW END MVFR CIGS. BREEZY CONDITIONS EXPECTED
SATURDAY WITH PLENTY OF CLOUDINESS...MAINLY VFR AFTER 13Z/14Z.
EXPECT WINDS TO SHIFT A BIT MORE NW/NNW BY SATURDAY EVENING BUT
REMAINING UP AROUND 10 TO 15 KTS WITH PLENTY OF HIGH CLOUDS AS
SANDY WILL BE SE OF CHARLESTON.
EXTENDED AVIATION OUTLOOK...BREEZY CONDITIONS MAY CONTINUE THROUGH
MONDAY...OTHERWISE NO MAJOR RESTRICTIONS FOR AVIATION INTERESTS
EXPECTED.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...LAKE WIND ADVISORY UNTIL 10 PM EDT SUNDAY FOR SCZ015-016-018-
020>022-025>031-035>038-041.
GA...LAKE WIND ADVISORY UNTIL 10 PM EDT SUNDAY FOR GAZ040-063>065-
077.
&&
$$
AREA FORECAST DISCUSSION
NWS BUFFALO NY
1024 AM EDT SAT OCT 27 2012
.SYNOPSIS...
A COLD FRONT WILL STALL ACROSS NEW YORK...WITH PERIODS OF RAIN AND
COOL TEMPERATURES ACROSS WESTERN NEW YORK THROUGH THE WEEKEND. THE
REMNANTS OF SANDY WILL APPROACH THE REGION NEXT WEEK...RESULTING IN
AN EXTENDED PERIOD OF HEAVY RAIN AND VERY WINDY CONDITIONS EARLY
NEXT WEEK. THE RAIN MAY RESULT IN MINOR FLOODING...AND STRONG WINDS
MAY PRODUCE WIND DAMAGE.
&&
.NEAR TERM /THROUGH TONIGHT/...
RADAR IMAGERY SHOWING STEADY LIGHT RAIN ACROSS THE FAR WESTERN END
OF THE STATE THIS MORNING...WITH SCATTERED SHOWERS AS FAR EAST AS A
LINE FROM WESTERN CATTARAUGUS COUNTY TO WARSAW AND ROCHESTER. EXPECT
THE RAIN TO REMAIN IN THE SAME BASIC POSITION THROUGH EARLY TO MID
AFTERNOON WITH THE SURFACE FRONT AND MID LEVEL FORCING ESSENTIALLY
STALLED. LATE TODAY THE EASTERN EDGE OF THE RAIN WILL BEGIN TO MOVE
EASTWARD SLOWLY.
A COLD FRONT WILL REMAIN NEARLY STATIONARY ACROSS CENTRAL NEW
YORK TODAY. THIS KEEP ALL OR MOST OF OUR CWA ON THE COOL SIDE OF
THE BOUNDARY. THE FRONT WILL NOT MOVE MUCH TONIGHT...POSSIBLY
MEANDERING JUST A BIT TO THE EAST...BUT FOR THE MOST PART IT WILL
BE STATIONARY.
DESPITE THE POSITION OF THE FRONT...IT IS A TIGHT TEMPERATURE
GRADIENT ALOFT WHICH SERVES AS THE MAIN FOCUS FOR RAIN. A CONSENSUS
OF THE 00Z NAM/RGEM/SREF/GFS GUIDANCE GRADUALLY SHIFT THIS AXIS TO
THE EAST LATER TODAY...WHICH IS A BIT MORE MOVEMENT THAN THE SURFACE
FRONT. RECENT RUNS OF THE HRRR AND RADAR TRENDS SUGGEST A SLIGHTLY
SLOWER PROGRESSION THAN THIS MODEL CONSENSUS...BUT THE TREND SHOULD
BE FINE.
PROVIDING SECONDARY SUPPORT TO THIS BOUNDARY IS DIVERGENCE
ALOFT IN THE RIGHT REAR QUADRANT OF THE UPPER JET. WITH LITTLE
FLOW PERPENDICULAR TO TEMPERATURE GRADIENT...THE COMBINATION OF
THESE FEATURES WILL ONLY PRODUCE A BAND OF LIGHT TO OCCASIONALLY
MODERATE RAIN. RAIN WILL LARGELY REMAIN WEST OF ROCHESTER THROUGH
THE MORNING HOURS TODAY...GRADUALLY SHIFTING EAST TOWARD WATERTOWN
AND SYRACUSE THIS AFTERNOON AND EVENING. THE BAND WILL STALL...OR
EVEN DRIFT BACK WESTWARD TOWARD DAYBREAK SUNDAY MORNING. DESPITE THE
MODEST RAINFALL RATES...THE PERSISTENCE OF THE BAND WILL PRODUCE
SOME DECENT 24 HOUR RAIN TOTALS. MODEL CONSENSUS SUGGESTS BETWEEN
.50 INCHES AND 1.00 INCHES WEST OF ROCHESTER...QUICKLY TAPERING
DOWN TO A TENTH OF AN INCH OR LESS IN EASTERN PORTIONS OF THE CWA.
ITS IMPORTANT TO NOTE THAT THE RAIN IS ASSOCIATED WITH THE
FRONT...AND NOT TROPICAL SYSTEM SANDY. THERE ALSO VIRTUALLY TO NO
THREAT FOR FLOODING THROUGH EARLY SUNDAY MORNING...AS IT WILL BE A
JUST A SOAKING RAINFALL DUE TO THIS FRONT.
TEMPERATURES WILL BE NOTABLY COOLER TODAY...WITH MOST OF THE REGION
ON THE COLD SIDE OF THE FRONT...ESPECIALLY CONSIDERING WE ARE COMING
OFF OF TWO UNSEASONABLY WARM DAYS. GIVEN THE SHALLOW COOL AIR AT THE
SURFACE...EXPECT MOST TEMPERATURE GUIDANCE IS A BIT TOO WARM IN
WESTERN SECTIONS...WHERE IT WILL BE RAINING MOST OF THE DAY. A BLEND
OF THE BIAS CORRECTED SREF AND RGEM WAS USED FOR MOST OF THE
TEMPERATURES...BOTH OF WHICH WERE ON THE COOL SIDE EAST OF THE FRONT
FOR HIGHS TODAY. TEMPERATURES MAY NOT EVEN TOP 50 DEGREES WEST OF
ROCHESTER...WITH HIGHS WARMING TO THE UPPER 50S TO LOWER 60S EAST.
EXPECT PATCHY FOG TO PERSIST THROUGH THE PERIOD...MAINLY ACROSS
HIGHER TERRAIN.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/...
THE FOCUS THIS TIME PERIOD WILL FOCUS ON SANDY AND ITS IMPACTS
UPON NOT ONLY WESTERN AND NORTH CENTRAL NEW YORK...BUT ALONG THE
ENTIRE EASTERN COASTLINE. FIRST...BEFORE WE GET TO SANDY ON MONDAY
LETS LOOK AT SUNDAY.
AN INVERTED TROUGH WILL BE FOUND NUDGING NORTHWARD THROUGH EASTERN
NEW YORK...WITH A STALLED FRONTAL BOUNDARY JUST TO THE WEST OF THIS
TROUGH. ALOFT AN EASTERLY WIND...OR WARM CONVEYOR BELT WILL
TRANSPORT MOISTURE WESTWARD...WITH PWATS RISING TO +1 TO +2SD ABOVE
NORMAL. THIS FRONTAL BOUNDARY WILL AGAIN FOCUS A PERIOD OF LIGHT
RAIN ACROSS THE CWA...WITH THE RIGHT ENTRANCE REGION OF AN 120 KNOT
250 HPA JET OVER WNY SUPPLYING ADDITIONAL SYNOPTIC LIFT. IT IS UNDER
THIS JET ENTRANCE REGION WHERE THE RAIN MIGHT BECOME MODERATE AT
TIMES. WILL PAINT THE HIGHEST QPF ACROSS WNY FOR SUNDAY-SUNDAY
NIGHT.
SUNDAY NIGHT MOISTURE WILL CONTINUE TO STREAM WESTWARD ACROSS THE
CWA AHEAD OF SANDY. A PERIOD OF LIGHT RAIN WILL AT FIRST FOCUS
ACROSS WNY NEAR THE FRONTAL BOUNDARY...THEN LATER MOISTURE STREAMING
NORTHWARD OF SANDY...INTERACTING WITH THE NEARING UPPER LEVEL TROUGH
MAY BRING SOME RAIN LATE SNEAKING INTO CENTRAL NEW YORK.
AS FOR QPF SUNDAY AND SUNDAY NIGHT A RANGE OF JUST A FEW TENTH OF AN
INCH TOWARDS FAR EASTERN PORTIONS OF THE CWA...AND UPWARDS TO AN
INCH ACROSS FAR WNY IN THE VICINITY OF THE FRONTAL BOUNDARY AND
UPPER LEVEL JET ENTRANCE REGION.
THOUGH WE WILL HAVE AN EASTERLY WIND SEVERAL THOUSAND FEET OFF THE
SFC...A BOUNDARY LAYER NORTHERLY WIND WILL CONTINUE TO RAW FEEL TO
THE DAY SUNDAY. HIGHS SUNDAY WILL REMAIN IN THE 40S WEST OF THE SFC
TROUGH...WHILE ALONG I-81 EASTWARD HIGHS WILL LIKELY AVERAGE 50F.
SUNDAY NIGHT WE WILL DROP BACK INTO THE 30S ACROSS WNY...AND MID 40S
TO THE EAST WHERE WARMER AIR CONTINUES TO PUSH WESTWARD FROM THE
ATLANTIC. STILL CANNOT RULE OUT SOME WET HIGHER ELEVATION SNOWFLAKES
ACROSS SOUTHWESTERN NEW YORK STATE.
DISCUSSION ON SANDY...
FIRST A LOOK AT THE MAJOR FEATURES FOR THIS TIME PERIOD. HURRICANE
SANDY IS CURRENTLY SPINNING ON A NORTH TO NORTHEAST TRACK NORTH OF
THE BAHAMAS AND OFF THE FLORIDA COASTLINE THIS MORNING. ON WATER
VAPOR IMAGERY A SHORT WAVE IS FOUND OVER SOUTHERN BRITISH
COLUMBIA...AND THIS FEATURE WILL CARVE A DEEPER CENTRAL US TROUGH
THAT WILL SLIDE EASTWARD...BECOME NEGATIVELY TILTED AND CAPTURE SANDY. TO
OUR EAST A +2SD RIDGE AT 500 HPA IS LOCATED ACROSS EASTERN ATLANTIC
CANADA AND TOWARDS GREENLAND. THIS RIDGE OVER GREENLAND SUPPORTS THE
NEGATIVE PHASE OF THE NAO...AND A NEGATIVE PHASE OF THE NAO CAN
ELUDE TO A BLOCKING PATTERN. THIS BLOCKING PATTERN IS WHAT WILL
ALLOW THE TROUGH TO OUR WEST TO CAPTURE AND TURN SANDY WESTWARD
ACROSS THE EASTERN COASTLINE.
THE DETERMINISTIC 27/00Z MODEL OF THE ECMWF CONTINUES TO DRIVE SANDY
INTO THE DELMARVA PENINSULA MONDAY...WHILE THE DETERMINISTIC 26/00Z
GFS PUSHES SANDY WESTWARD ALONG THE SOUTHERN SHORELINE OF LONG
ISLAND THROUGH THE COURSE OF TUESDAY. THE GEFS MEMBERS SPREAD FROM
NEAR THE EUROPEAN SOLUTION...WHILE SOME MEMBERS BRING SANDY MUCH
FARTHER NORTHWARD MAKING LANDFALL IN NEW ENGLAND. THAT SAID WE ARE
FAIRLY CERTAIN SANDY WILL MAKE LANDFALL SOMETIME EARLY NEXT WEEK
WITH IMPLICATIONS NOW LEANING TOWARDS A PROLONGED RAIN WITH THE
POTENTIAL FOR RIVER AND URBAN FLOODING AND POSSIBLE HIGH WIND THREAT.
IT IS STILL TO EARLY AND TOO MUCH UNCERTAINTY FOR ANY
HEADLINES...BUT WE WILL CONTINUE TO MENTION THE THREATS IN OUR HWO
PRODUCT AS WELL AS HERE BELOW IN THE AFD.
RAIN AND FLOODING...BOTH THE ECMWF AND GFS LINGER A FRONTAL BOUNDARY
ACROSS WNY...AND MOISTURE SURGING WESTWARD TOWARDS THIS FRONT COULD
LEAD TO A PERIOD OF MODERATE TO HEAVY RAIN BEGINNING AS EARLY AS
MONDAY...WITH THE FOCUS OF HEAVY RAIN ACROSS WNY. AS SANDY MOVES
INLAND WE ARE EXPECTING SEVERAL PERIODS OF RAIN IN THE MONDAY
THROUGH TUESDAY NIGHT TIME FRAME...WITH THE HEAVIEST RAIN LIKELY
MONDAY NIGHT AND THROUGH TUESDAY. WE WILL HIGHLIGHT THIS HEAVY RAIN
POTENTIAL IN THE GRIDS. IT IS STILL A LITTLE EARLY TO FOCUS WHERE
THE HEAVIEST RAIN WILL FALL...AND HOW MUCH BUT SEVERAL INCHES OF
RAIN IS EXPECTED.
A LOOK AT THE GEFS MODEL ENSEMBLE RIVER FORECASTS SHOWS THAT SOME OF
OUR CREEKS AND RIVERS...ESPECIALLY ACROSS WESTERN NEW YORK AND THE
GENESEE VALLEY WILL NEED TO BE WATCHED FOR RIVER HEIGHT RISES. A FEW
MEMBERS OF THIS ENSEMBLE DO BRING SEVERAL OF OUR CREEKS...BOTH QUICK
AND SLOW RISERS INTO MINOR FLOODING IN THE MONDAY THROUGH WEDNESDAY
TIMEFRAME. WITH RAINFALL SINCE SEPTEMBER 1ST AROUND AN INCH OR SO
ABOVE NORMAL...AND COMBINED WITH THE WEEKEND RAIN...OUR CREEKS AND
RIVERS THAT WERE PRETTY LOW OVER THE SUMMER HAVE LARGELY RECOVERED
FROM THEIR LOW FLOW. THIS INCREASE IN RIVER FLOW THIS AUTUMN WILL
ONLY INCREASE THE POSSIBILITIES OF ANY RIVER FLOODING NEXT WEEK...AS
WELL AS SMALL CREEKS.
THERE IS ALSO THE POTENTIAL FOR URBAN AND POOR DRAINAGE FLOODING.
THOUGH WE ARE EXPECTING SEVERAL INCHES OF RAINFALL...THIS WILL OCCUR
OVER A SEVERAL DAY TIME PERIOD POSSIBLY ALLOWING THE GROUND TO
HANDLE SUCH HIGH RAINFALLS.
WIND...THE SECOND BIG CONCERN WITH SANDY FOR OUR AREA WILL BE WIND.
AS SANDY PUSHES INLAND AND NEARS OUR REGION AN INCREASE IN WIND
SPEED...LIKELY A NORTH TO NORTHEAST WIND... IS EXPECTED. AGAIN
MODELS WILL LIKELY FLUCTUATE ON WIND SPEED AND PLACEMENT OF PEAK
GUSTS WITH THE TRACK OF THE SYSTEM AND PINPOINTING SPEEDS AT THIS
TIME IS UNCERTAIN. THE HIGHEST WINDS SPEEDS WILL LIKELY COME MONDAY
NIGHT AND INTO TUESDAY BASED OFF BOTH THE CURRENT MODEL RUNS OF THE
27/00Z ECMWF AND GFS. WITH THIS WIND DIRECTION THE AREA MOST LIKELY
IMPACTED BY THE WINDS WILL BE LAKE ONTARIO AND ITS SOUTHERN
SHORELINES. PAST TROPICAL OR DEEP SURFACE LOW EVENTS HAVE SHOWN EVEN
SUBWARNING WIND SPEEDS CAN FALL TREES AS THE NORTHEAST WIND
DIRECTION IS NOT A COMMON HIGH SPEED DIRECTION FOR OUR REGION.
SNOW...THIS IMPACT IS BECOMING LESS LIKELY AS WARM AIR WRAPPING
ACROSS OUR REGION WILL LEAVE THE BOUNDARY LAYER TOO WARM TO SUPPORT
SNOW. TEMPERATURES WILL COOL SOME AT NIGHT AND THERE IS STILL A CHC
FOR HIGHER ELEVATION SNOW MONDAY NIGHT ACROSS SOUTHWESTERN NEW YORK
STATE.
PLEASE CONTINUE TO MONITOR YOUR NATIONAL WEATHER SERVICE FORECAST
FOR UPDATES THROUGH THE WEEKEND AS WE CONTINUE TO FINE TUNE THE
DETAILS.
&&
.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
THIS TIME PERIOD WILL START WITH THE DECAYING REMNANTS OF SANDY
EARLY IN THE PERIOD...TRANSITIONING TO POSSIBLE SNOW BY THE END OF
THE WEEK.
WEDNESDAY THE REMNANT LOW OF SANDY WILL CONTINUE TO BE QUICKLY
FILLING...THOUGH STILL DEEP. POSITION OF WHERE THE LOW WILL BE IS
STILL UNCERTAIN WITH THE 27/00Z ECMWF LINGERING THE LOW NEAR THE
ATLANTIC COASTLINE OF THE MID ATLANTIC STATES...WHILE THE 27/00Z GFS
BRINGS THE LOW FARTHEST INLAND TO NEAR LAKE ERIE. A CONSENSUS OF
THESE TWO MODELS MATCHES CLOSELY WITH THE NHC TRACK WHICH PLACES THE
LOW OVER CENTRAL PENNSYLVANIA. WILL CONTINUE WITH LIKELY POPS ON
WEDNESDAY FOR SHOWERS AS THE SYSTEM CONTINUES TO FILL AND LOW LEVEL
OMEGA DISPLAYS LITTLE UPWARD MOTION. QPF WEDNESDAY WILL LIKELY RANGE
FROM HALF AN INCH OR LESS.
WEDNESDAY NIGHT THROUGH THURSDAY NIGHT THE UPPER LEVEL FLOW WILL
REMAIN CUT OFF FROM THE MAIN JET STREAM...ALLOWING THE REMNANT LOW
OF SANDY TO SLOWLY SPIRAL NORTHEASTWARD. THIS WILL LEAD TO ADDITIONAL
PROLONGED PERIOD OF SHOWERS.
BY FRIDAY A MID LEVEL TROUGH WILL BE BARRELING TOWARDS THE ROCKIES
FORCING A DOWNSTREAM UPPER LEVEL RIDGE OVER THE PLAINS. THIS RIDGE
WILL NUDGE THE UPPER LEVEL CUTOFF LOW EASTWARD WITH A COOL
NORTHWESTERLY FLOW THEN REACHING THE CWA. TEMPERATURES AT 850 HPA
DROP TO -1 TO -2C WHICH MAY ALLOW FOR SOME LAKE ENHANCED RAIN AND OR
SNOW SHOWERS ON FRIDAY.
TEMPERATURES THIS THREE DAY TIME PERIOD WILL RUN IN THE 40S BY
DAY...AND 40S TO SOUTHERN TIER INLAND VALLEYS 30S BY NIGHT.
&&
.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
A STALLED SURFACE FRONT WILL REMAIN ACROSS CENTRAL NEW YORK...AND
EAST OF THE TAF SITES. MEANWHILE...A TIGHT TEMPERATURE GRADIENT ALOFT
WHICH IS ASSOCIATED WITH THE FRONT WILL SERVE AS THE FOCUS FOR
RAIN. BOTH OF THESE WILL MOVE VERY LITTLE...EVER SO GRADUALLY
SLIDING EAST TODAY AND TONIGHT.
THIS WILL RESULT IN A PERSISTENT AND MOIST NNE FLOW ACROSS THE
REGION...WHICH TENDS TO BE FAIRLY FAVORABLE FOR LOW CIGS THIS TIME
OF YEAR. 12Z CONDITIONS WERE MAINLY IFR...WITH FAIRLY HIGH
CONFIDENCE THAT THIS WILL PERSIST FOR MUCH OF TODAY AND TONIGHT.
OUTLOOK...
SUNDAY THROUGH WEDNESDAY...PERIODS OF RAIN WITH ASSOCIATED
IFR/MVFR CONDITIONS.
&&
.MARINE...
A COLD FRONT STALL OVER EASTERN NEW YORK TODAY. A NORTHERLY
FLOW OF NOTICEABLY COLDER AIR BEHIND THE FRONT WILL RESULT IN SCA
CONDITIONS ALONG THE SOUTHERN SHORES OF BOTH LAKES THROUGH SUNDAY.
THERE IS AN INCREASING POTENTIAL FOR STRONGER WINDS EARLY NEXT WEEK
AS SANDY INTERACTS WITH AN UPPER LEVEL TROF ACROSS THE EASTERN LAKES
EARLY NEXT WEEK. WHILE THE EXACT TRACK AND STRENGTH OF THE STORM IS
UNCERTAIN...IT DOES APPEARS THE STRONGEST WINDS ON BOTH LAKES WILL
LIKELY OCCUR LATE MONDAY THROUGH TUESDAY MORNING. MODEL GUIDANCE
SUGGESTS GALE OR STORM FORCE WINDS ARE A POSSIBILITY DURING THIS
PERIOD.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR LEZ041.
SMALL CRAFT ADVISORY UNTIL 6 PM EDT SUNDAY FOR LEZ040.
SMALL CRAFT ADVISORY UNTIL 6 PM EDT SUNDAY FOR
LOZ042>044.
&&
$$
SYNOPSIS...APFFEL/HITCHCOCK
NEAR TERM...APFFEL/HITCHCOCK
SHORT TERM...THOMAS
LONG TERM...THOMAS
AVIATION...APFFEL
MARINE...APFFEL/THOMAS
AREA FORECAST DISCUSSION
NWS BUFFALO NY
726 AM EDT SAT OCT 27 2012
.SYNOPSIS...
A COLD FRONT WILL STALL ACROSS NEW YORK...WITH PERIODS OF RAIN AND
COOL TEMPERATURES ACROSS WESTERN NEW YORK THROUGH THE WEEKEND. THE
REMNANTS OF SANDY WILL APPROACH THE REGION NEXT WEEK...RESULTING IN
AN EXTENDED PERIOD OF RAIN WINDY CONDITIONS EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
A COLD FRONT WILL REMAIN NEARLY STATIONARY ACROSS CENTRAL NEW
YORK TODAY. THIS KEEP ALL OR MOST OF OUR CWA ON THE COOL SIDE OF
THE BOUNDARY. THE FRONT WILL NOT MOVE MUCH TONIGHT...POSSIBLY
MEANDERING JUST A BIT TO THE EAST...BUT FOR THE MOST PART IT WILL
BE STATIONARY.
DESPITE THE POSITION OF THE FRONT...IT IS A TIGHT TEMPERATURE
GRADIENT ALOFT WHICH SERVES AS THE MAIN FOCUS FOR RAIN. THIS FOCUS
IS TO THE WEST OF THE SURFACE FRONT...ACROSS EASTERN PORTIONS OF
LAKE ERIE AND THE NIAGARA FRONTIER AT DAYBREAK. A CONSENSUS OF
THE 00Z NAM/RGEM/SREF/GFS GUIDANCE GRADUALLY SHIFT THIS AXIS TO
THE EAST TODAY...WHICH IS A BIT MORE MOVEMENT THAN THE SURFACE
FRONT. RECENT RUNS OF THE HRRR AND RADAR TRENDS SUGGEST A SLIGHTLY
SLOWER PROGRESSION THAN THIS MODEL CONSENSUS...BUT THE TREND
SHOULD BE FINE.
PROVIDING SECONDARY SUPPORT TO THIS BOUNDARY IS DIVERGENCE
ALOFT IN THE RIGHT REAR QUADRANT OF THE UPPER JET. WITH LITTLE
FLOW PERPENDICULAR TO TEMPERATURE GRADIENT...THE COMBINATION OF
THESE FEATURES WILL ONLY PRODUCE A BAND OF LIGHT TO OCCASIONALLY
MODERATE RAIN. RAIN WILL LARGELY REMAIN WEST OF ROCHESTER THROUGH
THE MORNING HOURS TODAY...GRADUALLY SHIFTING EAST TOWARD WATERTOWN AND
SYRACUSE THIS AFTERNOON AND EVENING. THE BAND WILL STALL...OR EVEN
DRIFT BACK WESTWARD TOWARD DAYBREAK SUNDAY MORNING. DESPITE THE
MODEST RAINFALL RATES...THE PERSISTENCE OF THE BAND WILL PRODUCE
SOME DECENT 24 HOUR RAIN TOTALS. MODEL CONSENSUS SUGGESTS BETWEEN
.50 INCHES AND 1.00 INCHES WEST OF ROCHESTER...QUICKLY TAPERING
DOWN TO A TENTH OF AN INCH OR LESS IN EASTERN PORTIONS OF THE CWA.
ITS IMPORTANT TO NOTE THAT THE RAIN IS ASSOCIATED WITH THE
FRONT...AND NOT TROPICAL SYSTEM SANDY. THERE ALSO VIRTUALLY TO NO
THREAT FOR FLOODING THROUGH EARLY SUNDAY MORNING...AS IT WILL BE A
JUST A SOAKING RAINFALL DUE TO THIS FRONT.
TEMPERATURES WILL BE NOTABLY COOLER TODAY...WITH MOST OF THE REGION
ON THE COLD SIDE OF THE FRONT...ESPECIALLY CONSIDERING WE ARE COMING
OFF OF TWO UNSEASONABLY WARM DAYS. GIVEN THE SHALLOW COOL AIR AT THE
SURFACE...EXPECT MOST TEMPERATURE GUIDANCE IS A BIT TOO WARM IN
WESTERN SECTIONS...WHERE IT WILL BE RAINING MOST OF THE DAY. A BLEND
OF THE BIAS CORRECTED SREF AND RGEM WAS USED FOR MOST OF THE
TEMPERATURES...BOTH OF WHICH WERE ON THE COOL SIDE EAST OF THE FRONT
FOR HIGHS TODAY. TEMPERATURES MAY NOT EVEN TOP 50 DEGREES WEST OF
ROCHESTER...WITH HIGHS WARMING TO THE UPPER 50S TO LOWER 60S EAST.
EXPECT PATCHY FOG TO PERSIST THROUGH THE PERIOD...MAINLY ACROSS
HIGHER TERRAIN.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/...
THE FOCUS THIS TIME PERIOD WILL FOCUS ON SANDY AND ITS IMPACTS
UPON NOT ONLY WESTERN AND NORTH CENTRAL NEW YORK...BUT ALONG THE
ENTIRE EASTERN COASTLINE. FIRST...BEFORE WE GET TO SANDY ON MONDAY
LETS LOOK AT SUNDAY.
AN INVERTED TROUGH WILL BE FOUND NUDGING NORTHWARD THROUGH EASTERN
NEW YORK...WITH A STALLED FRONTAL BOUNDARY JUST TO THE WEST OF THIS
TROUGH. ALOFT AN EASTERLY WIND...OR WARM CONVEYOR BELT WILL
TRANSPORT MOISTURE WESTWARD...WITH PWATS RISING TO +1 TO +2SD ABOVE
NORMAL. THIS FRONTAL BOUNDARY WILL AGAIN FOCUS A PERIOD OF LIGHT
RAIN ACROSS THE CWA...WITH THE RIGHT ENTRANCE REGION OF AN 120 KNOT
250 HPA JET OVER WNY SUPPLYING ADDITIONAL SYNOPTIC LIFT. IT IS UNDER
THIS JET ENTRANCE REGION WHERE THE RAIN MIGHT BECOME MODERATE AT
TIMES. WILL PAINT THE HIGHEST QPF ACROSS WNY FOR SUNDAY-SUNDAY
NIGHT.
SUNDAY NIGHT MOISTURE WILL CONTINUE TO STREAM WESTWARD ACROSS THE
CWA AHEAD OF SANDY. A PERIOD OF LIGHT RAIN WILL AT FIRST FOCUS
ACROSS WNY NEAR THE FRONTAL BOUNDARY...THEN LATER MOISTURE STREAMING
NORTHWARD OF SANDY...INTERACTING WITH THE NEARING UPPER LEVEL TROUGH
MAY BRING SOME RAIN LATE SNEAKING INTO CENTRAL NEW YORK.
AS FOR QPF SUNDAY AND SUNDAY NIGHT A RANGE OF JUST A FEW TENTH OF AN
INCH TOWARDS FAR EASTERN PORTIONS OF THE CWA...AND UPWARDS TO AN
INCH ACROSS FAR WNY IN THE VICINITY OF THE FRONTAL BOUNDARY AND
UPPER LEVEL JET ENTRANCE REGION.
THOUGH WE WILL HAVE AN EASTERLY WIND SEVERAL THOUSAND FEET OFF THE
SFC...A BOUNDARY LAYER NORTHERLY WIND WILL CONTINUE TO RAW FEEL TO
THE DAY SUNDAY. HIGHS SUNDAY WILL REMAIN IN THE 40S WEST OF THE SFC
TROUGH...WHILE ALONG I-81 EASTWARD HIGHS WILL LIKELY AVERAGE 50F.
SUNDAY NIGHT WE WILL DROP BACK INTO THE 30S ACROSS WNY...AND MID 40S
TO THE EAST WHERE WARMER AIR CONTINUES TO PUSH WESTWARD FROM THE
ATLANTIC. STILL CANNOT RULE OUT SOME WET HIGHER ELEVATION SNOWFLAKES
ACROSS SOUTHWESTERN NEW YORK STATE.
DISCUSSION ON SANDY...
FIRST A LOOK AT THE MAJOR FEATURES FOR THIS TIME PERIOD. HURRICANE
SANDY IS CURRENTLY SPINNING ON A NORTH TO NORTHEAST TRACK NORTH OF
THE BAHAMAS AND OFF THE FLORIDA COASTLINE THIS MORNING. ON WATER
VAPOR IMAGERY A SHORT WAVE IS FOUND OVER SOUTHERN BRITISH
COLUMBIA...AND THIS FEATURE WILL CARVE A DEEPER CENTRAL US TROUGH
THAT WILL SLIDE EASTWARD...BECOME NEGATIVELY TILTED AND CAPTURE SANDY. TO
OUR EAST A +2SD RIDGE AT 500 HPA IS LOCATED ACROSS EASTERN ATLANTIC
CANADA AND TOWARDS GREENLAND. THIS RIDGE OVER GREENLAND SUPPORTS THE
NEGATIVE PHASE OF THE NAO...AND A NEGATIVE PHASE OF THE NAO CAN
ELUDE TO A BLOCKING PATTERN. THIS BLOCKING PATTERN IS WHAT WILL
ALLOW THE TROUGH TO OUR WEST TO CAPTURE AND TURN SANDY WESTWARD
ACROSS THE EASTERN COASTLINE.
THE DETERMINISTIC 27/00Z MODEL OF THE ECMWF CONTINUES TO DRIVE SANDY
INTO THE DELMARVA PENINSULA MONDAY...WHILE THE DETERMINISTIC 26/00Z
GFS PUSHES SANDY WESTWARD ALONG THE SOUTHERN SHORELINE OF LONG
ISLAND THROUGH THE COURSE OF TUESDAY. THE GEFS MEMBERS SPREAD FROM
NEAR THE EUROPEAN SOLUTION...WHILE SOME MEMBERS BRING SANDY MUCH
FARTHER NORTHWARD MAKING LANDFALL IN NEW ENGLAND. THAT SAID WE ARE
FAIRLY CERTAIN SANDY WILL MAKE LANDFALL SOMETIME EARLY NEXT WEEK
WITH IMPLICATIONS NOW LEANING TOWARDS A PROLONGED RAIN WITH THE
POTENTIAL FOR RIVER AND URBAN FLOODING AND POSSIBLE HIGH WIND THREAT.
IT IS STILL TO EARLY AND TOO MUCH UNCERTAINTY FOR ANY
HEADLINES...BUT WE WILL CONTINUE TO MENTION THE THREATS IN OUR HWO
PRODUCT AS WELL AS HERE BELOW IN THE AFD.
RAIN AND FLOODING...BOTH THE ECMWF AND GFS LINGER A FRONTAL BOUNDARY
ACROSS WNY...AND MOISTURE SURGING WESTWARD TOWARDS THIS FRONT COULD
LEAD TO A PERIOD OF MODERATE TO HEAVY RAIN BEGINNING AS EARLY AS
MONDAY...WITH THE FOCUS OF HEAVY RAIN ACROSS WNY. AS SANDY MOVES
INLAND WE ARE EXPECTING SEVERAL PERIODS OF RAIN IN THE MONDAY
THROUGH TUESDAY NIGHT TIME FRAME...WITH THE HEAVIEST RAIN LIKELY
MONDAY NIGHT AND THROUGH TUESDAY. WE WILL HIGHLIGHT THIS HEAVY RAIN
POTENTIAL IN THE GRIDS. IT IS STILL A LITTLE EARLY TO FOCUS WHERE
THE HEAVIEST RAIN WILL FALL...AND HOW MUCH BUT SEVERAL INCHES OF
RAIN IS EXPECTED.
A LOOK AT THE GEFS MODEL ENSEMBLE RIVER FORECASTS SHOWS THAT SOME OF
OUR CREEKS AND RIVERS...ESPECIALLY ACROSS WESTERN NEW YORK AND THE
GENESEE VALLEY WILL NEED TO BE WATCHED FOR RIVER HEIGHT RISES. A FEW
MEMBERS OF THIS ENSEMBLE DO BRING SEVERAL OF OUR CREEKS...BOTH QUICK
AND SLOW RISERS INTO MINOR FLOODING IN THE MONDAY THROUGH WEDNESDAY
TIMEFRAME. WITH RAINFALL SINCE SEPTEMBER 1ST AROUND AN INCH OR SO
ABOVE NORMAL...AND COMBINED WITH THE WEEKEND RAIN...OUR CREEKS AND
RIVERS THAT WERE PRETTY LOW OVER THE SUMMER HAVE LARGELY RECOVERED
FROM THEIR LOW FLOW. THIS INCREASE IN RIVER FLOW THIS AUTUMN WILL
ONLY INCREASE THE POSSIBILITIES OF ANY RIVER FLOODING NEXT WEEK...AS
WELL AS SMALL CREEKS.
THERE IS ALSO THE POTENTIAL FOR URBAN AND POOR DRAINAGE FLOODING.
THOUGH WE ARE EXPECTING SEVERAL INCHES OF RAINFALL...THIS WILL OCCUR
OVER A SEVERAL DAY TIME PERIOD POSSIBLY ALLOWING THE GROUND TO
HANDLE SUCH HIGH RAINFALLS.
WIND...THE SECOND BIG CONCERN WITH SANDY FOR OUR AREA WILL BE WIND.
AS SANDY PUSHES INLAND AND NEARS OUR REGION AN INCREASE IN WIND
SPEED...LIKELY A NORTH TO NORTHEAST WIND... IS EXPECTED. AGAIN
MODELS WILL LIKELY FLUCTUATE ON WIND SPEED AND PLACEMENT OF PEAK
GUSTS WITH THE TRACK OF THE SYSTEM AND PINPOINTING SPEEDS AT THIS
TIME IS UNCERTAIN. THE HIGHEST WINDS SPEEDS WILL LIKELY COME MONDAY
NIGHT AND INTO TUESDAY BASED OFF BOTH THE CURRENT MODEL RUNS OF THE
27/00Z ECMWF AND GFS. WITH THIS WIND DIRECTION THE AREA MOST LIKELY
IMPACTED BY THE WINDS WILL BE LAKE ONTARIO AND ITS SOUTHERN
SHORELINES. PAST TROPICAL OR DEEP SURFACE LOW EVENTS HAVE SHOWN EVEN
SUBWARNING WIND SPEEDS CAN FALL TREES AS THE NORTHEAST WIND
DIRECTION IS NOT A COMMON HIGH SPEED DIRECTION FOR OUR REGION.
SNOW...THIS IMPACT IS BECOMING LESS LIKELY AS WARM AIR WRAPPING
ACROSS OUR REGION WILL LEAVE THE BOUNDARY LAYER TOO WARM TO SUPPORT
SNOW. TEMPERATURES WILL COOL SOME AT NIGHT AND THERE IS STILL A CHC
FOR HIGHER ELEVATION SNOW MONDAY NIGHT ACROSS SOUTHWESTERN NEW YORK
STATE.
PLEASE CONTINUE TO MONITOR YOUR NATIONAL WEATHER SERVICE FORECAST
FOR UPDATES THROUGH THE WEEKEND AS WE CONTINUE TO FINE TUNE THE
DETAILS.
&&
.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
THIS TIME PERIOD WILL START WITH THE DECAYING REMNANTS OF SANDY
EARLY IN THE PERIOD...TRANSITIONING TO POSSIBLE SNOW BY THE END OF
THE WEEK.
WEDNESDAY THE REMNANT LOW OF SANDY WILL CONTINUE TO BE QUICKLY
FILLING...THOUGH STILL DEEP. POSITION OF WHERE THE LOW WILL BE IS
STILL UNCERTAIN WITH THE 27/00Z ECMWF LINGERING THE LOW NEAR THE
ATLANTIC COASTLINE OF THE MID ATLANTIC STATES...WHILE THE 27/00Z GFS
BRINGS THE LOW FARTHEST INLAND TO NEAR LAKE ERIE. A CONSENSUS OF
THESE TWO MODELS MATCHES CLOSELY WITH THE NHC TRACK WHICH PLACES THE
LOW OVER CENTRAL PENNSYLVANIA. WILL CONTINUE WITH LIKELY POPS ON
WEDNESDAY FOR SHOWERS AS THE SYSTEM CONTINUES TO FILL AND LOW LEVEL
OMEGA DISPLAYS LITTLE UPWARD MOTION. QPF WEDNESDAY WILL LIKELY RANGE
FROM HALF AN INCH OR LESS.
WEDNESDAY NIGHT THROUGH THURSDAY NIGHT THE UPPER LEVEL FLOW WILL
REMAIN CUT OFF FROM THE MAIN JET STREAM...ALLOWING THE REMNANT LOW
OF SANDY TO SLOWLY SPIRAL NORTHEASTWARD. THIS WILL LEAD TO ADDITIONAL
PROLONGED PERIOD OF SHOWERS.
BY FRIDAY A MID LEVEL TROUGH WILL BE BARRELING TOWARDS THE ROCKIES
FORCING A DOWNSTREAM UPPER LEVEL RIDGE OVER THE PLAINS. THIS RIDGE
WILL NUDGE THE UPPER LEVEL CUTOFF LOW EASTWARD WITH A COOL
NORTHWESTERLY FLOW THEN REACHING THE CWA. TEMPERATURES AT 850 HPA
DROP TO -1 TO -2C WHICH MAY ALLOW FOR SOME LAKE ENHANCED RAIN AND OR
SNOW SHOWERS ON FRIDAY.
TEMPERATURES THIS THREE DAY TIME PERIOD WILL RUN IN THE 40S BY
DAY...AND 40S TO SOUTHERN TIER INLAND VALLEYS 30S BY NIGHT.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
A STALLED SURFACE FRONT WILL REMAIN ACROSS CENTRAL NEW YORK...AND
EAST OF THE TAF SITES. MEANWHILE...A TIGHT TEMPERATURE GRADIENT ALOFT
WHICH IS ASSOCIATED WITH THE FRONT WILL SERVE AS THE FOCUS FOR
RAIN. BOTH OF THESE WILL MOVE VERY LITTLE...EVER SO GRADUALLY
SLIDING EAST TODAY AND TONIGHT.
THIS WILL RESULT IN A PERSISTENT AND MOIST NNE FLOW ACROSS THE
REGION...WHICH TENDS TO BE FAIRLY FAVORABLE FOR LOW CIGS THIS TIME
OF YEAR. 12Z CONDITIONS WERE MAINLY IFR...WITH FAIRLY HIGH
CONFIDENCE THAT THIS WILL PERSIST FOR MUCH OF TODAY AND TONIGHT.
OUTLOOK...
SUNDAY THROUGH WEDNESDAY...PERIODS OF RAIN WITH ASSOCIATED
IFR/MVFR CONDITIONS.
&&
.MARINE...
A COLD FRONT STALL OVER EASTERN NEW YORK TODAY. A NORTHERLY
FLOW OF NOTICEABLY COLDER AIR BEHIND THE FRONT WILL RESULT IN SCA
CONDITIONS ALONG THE SOUTHERN SHORES OF BOTH LAKES THROUGH SUNDAY.
THERE IS AN INCREASING POTENTIAL FOR STRONGER WINDS EARLY NEXT WEEK
AS SANDY INTERACTS WITH AN UPPER LEVEL TROF ACROSS THE EASTERN LAKES
EARLY NEXT WEEK. WHILE THE EXACT TRACK AND STRENGTH OF THE STORM IS
UNCERTAIN...IT DOES APPEARS THE STRONGEST WINDS ON BOTH LAKES WILL
LIKELY OCCUR ON MONDAY AND TUESDAY. MODEL GUIDANCE SUGGESTS GALES OR
STORM FORCE WINDS ARE A POSSIBILITY DURING THIS PERIOD.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR LEZ041.
SMALL CRAFT ADVISORY UNTIL 6 PM EDT SUNDAY FOR LEZ040.
SMALL CRAFT ADVISORY UNTIL 6 PM EDT SUNDAY FOR
LOZ042>044.
&&
$$
SYNOPSIS...APFFEL
NEAR TERM...APFFEL
SHORT TERM...THOMAS
LONG TERM...THOMAS
AVIATION...APFFEL
MARINE...APFFEL/THOMAS
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
1029 AM EDT SAT OCT 27 2012
.SYNOPSIS...
A COLD FRONT OOZES THROUGH THE CENTRAL APPALACHIANS TODAY. SANDY
COMBINES WITH A STRONG UPPER LEVEL SYSTEM TO IMPACT THE AREA SUNDAY
THROUGH MUCH OF NEXT WEEK...WITH WIND AND PROLONGED PRECIPITATION.
&&
.NEAR TERM /THROUGH TONIGHT/...
1000AM UPDATE...
JUST A FEW CHGS WITH MORNING UPDATE. SFC FRONT APPEARS TO BE HUNG
UP IN MTNS WITH H85 BOUNDARY LAGGING WELL BEHIND...INTO E OH. SFC
FRONT WILL BECOME HARDER TO FIND AS DAY WEARS ON AS OUTFLOW FROM
SANDY BEGIN TO OVERWHELM THE FLOW. EVEN H85 FRONT WILL EVENTUALLY
SUFFER THE SAME FATE. AREA OF POST SFC FRONTAL SHRA CONT IN SE OH AND
WESTERN LOWLANDS THIS MORNING...AIDED BY DEFORMATION AXIS WITH UPR
FRONT. THIS WILL SLOWLY SLIDE INTO CENTRAL LOWLANDS TDY BEFORE
PERHAPS RETREATING SOME BACK TOWARD OH RVR/SE OH THIS EVE. TWEAKED
POPS TO REFLECT CURRENT RADAR TRENDS THIS MORNING. MAYBE SOME
PATCHY DZ AS THIS WORKS IN...BUT STUCK WITH -SHRA AS PREDOMINATE
WX. LOW CIGS AND TMPS SLOWLY FALLING INTO UPR 40S ACROSS THE
LOWLANDS...WITH THE MTNS FALL THRU THEIR WARM MID/UPR 50S
CURRENTLY INTO UPR 40S/LWR 50S THIS EVE. DREARY DAY FOR ALL.
PREV DISCN...
EARLY THIS MORNING FINDS A S/W TROUGH OVER THE OHIO VALLEY DRIVING A
COLD FRONT THROUGH THE AREA...AND ADDITIONAL SHORT WAVE ENERGY
DIGGING INTO THE PLAINS BEHIND A L/R MIDWEST TROUGH...ALL WHILE
SANDY IS MOVING SLOWLY N...OUT E OF NORTHERN FL AND N OF THE BAHAMAS.
THE KEY TO THE NEXT 27 HOURS IS THE S/W ROTATION THROUGH THE L/R
TROUGH. THE OHIO VALLEY SHORT LIFTS THROUGH THE EASTERN GREAT LAKES
TODAY AND THEN INTO EASTERN CANADA TONIGHT. THE SURFACE COLD FRONT
NEARING THE WV MOUNTAINS EARLY THIS MORNING SLOWLY OOZES THROUGH
THERE TODAY...AND THEN ACTUALLY GETS ABSORBED INTO THE CIRCULATION
OF SANDY LATER TODAY AND TONIGHT.
THE PRECIPITATION BEHIND THE COLD FRONT MAKES VERY SLOW EWD
PROGRESS...BARELY MAKING IT ACROSS THE OHIO RIVER TODAY. COVERAGE
SHOULD ACTUALLY DIMINISH IN PLACE AS THE FORCING LIFTS OUT THIS
AFTERNOON AND EVENING. OVERNIGHT TONIGHT...THE ADDITIONAL S/W
ENERGY ON THE BACK SIDE OF THE L/R...ESSENTIALLY A SPEED
MAX...CARVES OUT A SHARP...NEGATIVE TILT S/W AS IT ROUNDS THE BASE
OF THE L/R. ITS FORCING INCREASES RAINFALL COVERAGE OVERNIGHT IN A
BAND EITHER SIDE OF THE OHIO RIVER BENEATH A DEFORMATION AXIS
FORMING THERE.
ALSO ADDED DRIZZLE TO THE FORECAST WITH THE PREPONDERANCE OF LOW
LEVEL MOISTURE AND UPSLOPE CONVERGENT LOW LEVEL FLOW.
BLENDED IN HRRR EARLY ON...THEN NAM12 TEMPERATURES AND DEW POINTS TO
BETTER DEPICT THE EVOLUTION OF THE RESPECTIVE GRADIENTS OVER THE
AREA ASSOCIATED WITH THE FRONT MOVING TO THE E. GENERALLY A LITTLE
HIGHER THAN PREVIOUS.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY/...
00Z MODELS IN FAIRLY GOOD AGREEMENT WITH A STALLED AREA OF PRECIP
ALONG THE OHIO RIVER TO START THE SHORT TERM...AND THEN SLOWLY
MERGE THIS INTO THE OVERALL PRECIP SHIELD OF SANDY SUNDAY NIGHT
INTO MONDAY...WITH THE HIGHEST POPS SLIDING INTO THE EASTERN CWA AS
SANDY MAKES LANDFALL. STILL SOME DIFFERENCES IN EXACT LAND
FALL...WITH GFS/NAM SHOWING A CENTRAL/NORTHERN NJ ENTRY POINT...AND
THE ECMWF A BIT SOUTH IN DELMARVA.
NO MATTER THE EXACT LANDFALL...CONFIDENCE CONTINUES TO INCREASE IN A
HIGH PRECIP/HIGH WIND FORECAST...WITH THE GREATEST IMPACTS IN THE
HIGHER TERRAIN WHERE ACCUMULATING UPSLOPE-ENHANCED SNOW AND 40+ KT
WIND GUSTS COULD CREATE QUITE THE WINTER STORM WITH DRIFTING AND LOW
VISIBILITY IN BLOWING SNOW.
INHERITED THE WINTER STORM WATCH...AND AFTER REWORKING THE SNOW
GRIDS DID NOT FEEL CHANGES TO THE HEADLINE WHERE NEEDED AT THIS
TIME. TEMPERATURE ADVECTION...AND ULTIMATELY WHERE THE BEST TEMP
PROFILE FOR SNOW SETS UP...IS KIND OF TRICKY WITH THIS WRAPPED UP
SYSTEM. WILL LIKELY SEE WAA COMING IN ON NORTH WINDS FOR A
TIME...AND THEN POSSIBLY SOME CAA COMING WITH MORE SOUTHWESTERLY
WINDS TOWARDS THE END OF THE SHORT TERM. AM NOT REAL CONFIDENT THAT
THE MODELS HAVE A GOOD HANDLE ON JUST WHERE THE COLDEST MIDLEVEL AIR
WILL BE...OR EVEN HOW COLD IT WILL BE. 00Z GFS/NAM AGREE ON -4C TO
-5C 850 TEMPS BY MONDAY NIGHT...WHILE 00Z ECMWF IS WARMER WITH -1C
TO -2C. THE GFS/NAM WOULD HINT TOWARDS SNOW ACROSS MOST OF THE CWA
BY MONDAY NIGHT...WHILE THE EURO KEEPS IT MORE IN THE MOUNTAINS.
WENT WITH A COMPROMISE...WITH ACCUMULATING SNOW IN THE
MOUNTAINS...AND A RAIN/SNOW MIX CLOSER TO THE OHIO RIVER. EVEN WITH
SOME FLAKES FALLING ACROSS THE LOWLANDS...THINK WITH THE WARM GROUND
ACCUMULATIONS WILL BE TOUGH TO COME BY.
&&
.LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/...
PRIMARY FORECAST CONCERN FOR THIS PERIOD OBVIOUSLY CONTINUES TO
REVOLVE AROUND SANDY/S TRACK AND POTENTIAL IMPACTS FOR THE NORTHEAST
CONUS IN GENERAL...AND SPECIFICALLY POTENTIAL IMPACTS FOR OUR
FORECAST AREA. WITH REGARD TO WHERE SANDY/S LANDFALL...NHC/S TRACK
HAS SHIFTED SOUTHWARD AND NOW BRINGS THE CENTER ASHORE OVER THE
DELMARVA PENINSULA. WITH THE STORM STILL BEING FOUR DAYS AWAY
SIGNIFICANT DIFFERENCES OBVIOUSLY STILL EXIST WITH HOW EXT GUIDANCE
HANDLES SANDY/S TRACK. TO SOME EXTENT EVEN GREATER UNCERTAINTY
EXISTS WITH HOW SANDY/S POST-TROPICAL EVOLUTION TAKES PLACE WITH
STRONG COLD AIR INTRUSION OUT OF THE NORTHWEST...AND THIS WILL HAVE
MAJOR RAMIFICATIONS AS TO THE SNOW/ICE IMPACTS OUR FORECAST AREA
EXPERIENCES AND TO A LESSER EXTENT WIND SPEEDS.
BREAKING DOWN THE SIG DIFFERENCES BETWEEN THE EXT MODELS AND
STARTING WITH THE 00Z EC...SANDY/S CENTER COMES ASHORE OVER DELMARVA
AREA MONDAY AFTERNOON AND SLOWLY MOVES TOWARDS THE EASTERN PANHANDLE
WV AREA BY 12Z TUE. THE SFC CENTER FILLS RAPIDLY BY TUESDAY MORNING
AS WELL WITH A SFC PRESS OF 982MB BY SAME TIME WITH WARM ADVECTION
WRAPPING AROUND THE BACKSIDE. THIS SCENARIO WOULD LIKELY MEAN MUCH
HIGHER PRECIP AMOUNTS FOR THE OVERALL AREA BUT WOULD ALSO MEAN A
LESSER LIKELIHOOD OF ACCUM SNOWFALL FOR LOWER ELEVATIONS AS THE
540DAM THICKNESS HEIGHT LINE REMAINS GENERALLY ALONG AND WEST OF OUR
FORECAST AREA. HIGH RAINFALL AMOUNTS BECOME THE BIGGER ISSUE WITH
THIS SCENARIO FOR LOWLANDS WITH A GENERAL 2-4 INCHES OF QPF DEPICTED
WITH HIGHER AMOUNTS CERTAINLY POSSIBLE.
MEANWHILE THE 12Z GFS CONTINUES TO BRING SANDY/S CENTER ASHORE NEAR
NYC TUES AFTERNOON WITH A SW RETROGRADE NEAR PHILLY BY TUE
EVE...BEFORE KICKING IT OUT TO THE N/NW WEDNESDAY. THIS SCENARIO
BRINGS A LONGER WIND EVENT CONTINUING WELL INTO TUE WITH THE SFC LOW
FARTHER AWAY. THIS SCENARIO ALSO ALLOWS COLDER AIR INTO THE
AREA...WITH THE 540DAM LINE COMPLETELY ENCOMPASSING AND WELL SOUTH
OF THE FORECAST AREA. THIS SCENARIO WOULD SPELL SNOWFALL FOR LOWLAND
LOCATIONS AS WELL. EVEN SO...WITH WARM SFC TEMPS FROM A WEEK OF VERY
WARM WEATHER IT WOULD PROBABLY TAKE SOME TIME BEFORE SNOW BEGINS TO
ACCUM ON ROADWAYS.
WITH ALL THIS IN MIND...WILL SIDE THE FORECAST TOWARDS THE EC WHICH
IS MUCH CLOSER TO NHC/S CURRENT TRACK AND THUS WILL LEAN THE
EVOLUTION OF THE SYSTEM IN THIS DIRECTION AS WELL. EITHER
WAY...THOUGH THE BEGINNING OF THE EVENT IS STILL 2-3 DAYS OUT
CONFIDENCE IS GROWING WITH A SIGNIFICANT SNOWFALL EVENT FOR THE HIGH
COUNTRY...PARTICULARLY FOR THE HIGHEST LOCATIONS SUCH AS SNOWSHOE.
IN COORDINATION WITH THE SHORT TERM FORECASTER...WILL KEEP WINTER
STORM WATCH FOR THESE AREAS GOING THROUGH 00Z WED WITH THE LONG
DURATION POTENTIAL. ACROSS THE LOWLANDS AMOUNTS GENERALLY UNDER TWO
INCHES ARE EXPECTED FOR WV ZONES...WITH MUCH OF IT COMING DURING THE
OVERNIGHT HOURS WITH PRIMARILY RAIN DURING THE DAY. LITTLE SNOW
SHOULD ACCUMULATE ON ROAD SURFACES WITH SUCH VERY WARM TEMPS IN
PLACE THIS WEEK. HAVE ALSO LOWERED MAX TEMPS TUESDAY AND WEDNESDAY.
AGAIN...STILL A GOOD DEAL OF UNCERTAINTY WITH THE FINAL TRACK AND
ANY SHIFT NORTH OR SOUTH COULD MAKE SUBSTANTIAL DIFFERENCES IN
RAIN/SNOW AMOUNTS RECEIVED AND WHERE...SNOW ACCUMULATIONS...ALONG
WITH WINDS.
&&
.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
MVFR CIGS OOZING E ACROSS AREA TODAY WILL THEN HANG AROUND THROUGH
THE BALANCE OF THE PERIOD...WITH OCCASIONAL IFR CIGS. RAIN SHOWERS
WILL BE MOST PREVALENT NEAR THE OHIO RIVER...WITH MVFR VSBY AT TIMES
THERE.
SURFACE FRONT WILL CROSS THE MOUNTAINS FIRST THING THIS
MORNING...WITH LIGHT SE FLOW AHEAD OF IT. OTHERWISE LIGHT N TO NW
SURFACE FLOW BEHIND THE FRONT WILL FRESHEN A BIT TODAY AND THEN
REMAIN NEAR 10 KTS MOST LOCALES TONIGHT...A BIT GUSTY ON THE
RIDGES. FRONT ALOFT WILL ENTER WESTERN WV THIS AFTERNOON AND THEN
STALL THERE. LIGHT N TO NE FLOW BEHIND THE FRONT WILL BE MODERATE N
TO NE THIS AFTERNOON AND TONIGHT. AHEAD OF THE FRONT ALOFT...LIGHT
S FLOW TODAY WILL BECOME LIGHT E TO NE LATE TODAY AND TONIGHT.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z SUNDAY...
FORECAST CONFIDENCE: MEDIUM HIGH.
ALTERNATE SCENARIOS: TIMING...PERSISTENCE AND EXTENT OF IFR CIGS AND
MVFR VSBYS MAY VARY.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01
EDT 1HRLY 10 11 12 13 14 15 16 17 18 19 20 21
CRW CONSISTENCY H H H H H H H H H H H H
HTS CONSISTENCY M M H H H H H H H H H H
BKW CONSISTENCY H H H H H H H H H H H H
EKN CONSISTENCY M M M M M M H H H H L L
PKB CONSISTENCY M H H H H H H H H H H H
CKB CONSISTENCY M M M M M M H H H H H H
AFTER 12Z SUNDAY...
IFR POSSIBLE IN RAIN AND SNOW SHOWERS WITH REMNANTS OF SANDY EARLY
NEXT WEEK. RAIN WILL BE THE DOMINANT PRECIPITATION TYPE OVER THE
LOW TERRAIN...WITH SNOW PREDOMINANT ACROSS THE HIGHER TERRAIN. THE
PRECIPITATION WILL TEND TO BE MORE IN THE FORM OF RAIN DURING THE
DAY...WHEN MOST OF WHAT IS SNOW IS WET SNOW. FOR THE OTHERWISE RAIN
DOMINATED LOWLANDS...WET SNOW IS POSSIBLE AT NT.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...WINTER STORM WATCH FROM LATE SUNDAY NIGHT THROUGH TUESDAY
EVENING FOR WVZ038-046-047.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...TRM
NEAR TERM...TRM/30
SHORT TERM...MZ
LONG TERM...50
AVIATION...TRM
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
1003 AM EDT SAT OCT 27 2012
.SYNOPSIS...
WEAK HIGH PRESSURE WILL PUSH INTO WESTERN OHIO TODAY. THE HIGH
WILL LOOSE ITS INFLUENCE AFTER TONIGHT HOWEVER AS HURRICANE SANDY
MOVES UP THE EAST COAST AND BEGINS TO DOMINATE THE WEATHER ACROSS
THE ENTIRE REGION FOR MUCH OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
CURRENT FORECAST IS ON TRACK WITH ONLY MINOR CHANGES PLANNED.
CLEARING IS NEAR TOL WITH LITTLE MOVEMENT. RAIN CONTINUES TO
STREAM NORTHEAST WITH A SLIGHT EASTWARD MOVEMENT OF THE WESTERN
EDGE FROM THE ISLANDS TO JUST WEST OF MNN. HRRR MOVES THE WESTERN
EDGE OF THE PCPN TO NEAR I-71 BY EARLY AFTERNOON WHICH SEEMS REASONABLE. RAIN
AND CLOUD COVER WILL INHIBIT MUCH WARMING SO WILL LOWER TEMPERATURES
A FEW DEGREES IN THE EASTERN AND CENTRAL COUNTIES.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/...
FOLLOWED THE NAM12 TRENDS THROUGH MUCH OF THE SHORT TERM.
OVERNIGHT NAM SHOWS DRY AIR CONTINUING ACROSS WESTERN COUNTIES
WHILE DEEP MOISTURE RETURNS FROM THE EAST ACROSS THE EASTERN HALF.
WILL MAINTAIN CAT POPS EAST OF ROUGHLY AN ASHTABULA TO CANTON
LINE. SUNDAY THE HIGH TO OUR WEST WILL CONTINUE TO WEAKEN ALLOWING
DEEP MOISTURE TO CONTINUE TO SHIFT WEST ACROSS THE REGION AS SANDY
MAKES ITS WAY NORTH OFF THE EAST COAST. THIS TREND WILL CONTINUE
THROUGH THE SHORT TERM WITH MOISTURE EVENTUALLY SPREADING WEST
OVER TOL TO FDY ON MONDAY. GREATEST POTENTIAL FOR RAIN WILL REMAIN
ACROSS THE EAST HALF OF THE AREA THROUGH THE PERIOD WITH 4-5
INCHES INDICATED BY HPC THROUGH THE NEXT 5 DAYS. PRECIP AMOUNTS
DROP OFF QUICKLY WEST. ALSO...WHILE NIGHTTIME TEMPS DROP OFF INTO
THE 30S THROUGH THE SHORT TERM...TEMPS ALOFT STILL TOO WARM FOR
SNOW AT LEAST ON CURRENT MODEL RUNS. CURRENTLY THE AREA IS NOT
OUTLOOKED FOR FLOOD POTENTIAL NEXT 3 DAYS SO NO FLOOD WATCH WOULD
BE NEEDED AT THIS TIME. OTHER ISSUE WOULD BE POTENTIAL FOR HIGH
WINDS. AGAIN...TOO EARLY FOR HEADLINES BUT MODELS TAKE THE
REMNANTS OF SANDY INTO PA MONDAY NIGHT REACHING NWRN PA TUESDAY
AFTERNOON. 09Z-12Z TUESDAY 850MB WINDS ARE FORECAST 60 TO 80 KNOTS
DEPENDING ON MODEL AND LOCATION WITH NUMERICAL GUIDANCE SUPPORTING
WIND HEADLINES ON LAND AND WATER WITH HIGHEST WINDS MONDAY NIGHT
THROUGH TUESDAY. OF COURSE...NEAR THE CENTER OF THE
CIRCULATION...WINDS WOULD BE MUCH LESS. ALL WILL DEPEND ON THE
PATH OF SANDY WHICH OF COURSE IS NOT SET IN STONE JUST YET.
&&
.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
BY WEDNESDAY THE WEATHER ACROSS THE AREA WILL BE MAINLY DRIVEN BY
WHAT IS LEFT OF HURRICANE SANDY AFTER IT MERGES WITH THE UPPER
TROUGH...WITH IS LOCATIONS EXPECTED TO BE SOMEWHERE OVER THE
INTERIOR MID ATLANTIC REGION TO NEW YORK STATE. WHILE THERE IS STILL
QUESTION AS TO THE EXACT TRACK OF THIS STORM...THE CYCLONIC FLOW
ACROSS THE AREA COMBINED WITH COLD TEMPS ALOFT WOULD AT LEAST ALLOW
FOR LAKE EFFECT/ENHANCED SHOWERS. ANY ADDITIONAL PRECIP WRAPPING
AROUND THE MAIN LOW WILL ONLY ADD TO PRECIP VALUES. WITH THAT
CONTINUED WITH LIKELY POPS ACROSS MUCH OF THE EASTERN HALF OF THE
AREA THROUGH THE END OF THE PERIOD WITH CHANCES ACROSS THE WEST. AS
THE LOW BEGINS TO MOVE OFF TO THE NORTHEAST LATE IN THE WEEK WINDS
SHIFTING W OR SW WITH CONTINUED COLDER AIR ALOFT AND PLENTY OF
MOISTURE WOULD ALLOW FOR LAKE EFFECT SHOWERS TO CONTINUE FOR NE
OH/NW PA...WHILE THE REMAINDER OF THE AREA WILL SEE A DRYING TREND.
AS FOR TEMPS MADE ONLY SMALL CHANGES. GIVEN THE SITUATION WITH
PLENTY OF CLOUDS AND SHOWERS...LEANED MORE TOWARD LOW DIURNAL WITH
TEMPS. WHILE HIGHS WILL REMAIN COOL THROUGH THE PERIOD DID NOT DROP
LOW TEMPS AS MUCH OF SOME GUIDANCE SHOWING WITH LOWS IN THE MID TO
UPPER 30S.
&&
.AVIATION /14Z SATURDAY THROUGH WEDNESDAY/...
RAIN CONTINUING ACROSS THE AREA THIS MORNING WITH WIDESPREAD
MVFR/IFR CONDITIONS. SATELLITE AND OBS SHOWING A SHARP CUTOFF TO
THE CLOUDS ACROSS NORTHWEST OHIO...WITH VFR CONDITIONS AT TOL BY
MID MORNING. WILL TAKE A LITTLE LONGER AT FDY...PERHAPS BY MIDDAY.
MVFR/IFR CONDITIONS WILL CONTINUE THROUGH AROUND MID AFTERNOON FOR
CLE AND MFD WITH IFR AT YNG THROUGH TODAY. ERI WILL SEE VARIABLE
MVFR/IFR CONDITIONS THROUGH MUCH OF TODAY.
MODELS SHOWING SHARP CLEARING PUSHING INTO THE N CNTRL OH EARLY
TONIGHT...BUT THEN BACKING TO THE WEST OVERNIGHT ALLOWING FOR
REDEVELOPMENT OF MVFR AND IFR FOR CLE AND MFD...AND CONTINUING FOR
SITES TO THE EAST. NORTHERLY WINDS 10-15KT GUSTING AROUND 20KT
THROUGH THE PERIOD.
.OUTLOOK...NON-VFR NE OH/NW PA SATURDAY NIGHT THROUGH MONDAY. NON-
VFR MOST AREAS TUESDAY AND WEDNESDAY.
&&
.MARINE...
HIGH PRESSURE OVER THE UPPER MIDWEST AND NORTHERN GREAT LAKES WILL
REMAIN IN PLACE THROUGH EARLY NEXT WEEK. MEANWHILE...HURRICANE SANDY
MOVING NORTH ALONG THE EAST COAST THROUGH THE WEEKEND WILL ALLOW FOR
NORTHERLY WINDS TO CONTINUE RANGING 15 TO 25 KNOTS THROUGH THE
WEEKEND WITH WAVES AT LEAST 4 FEET IN SOME LOCATIONS.
LATEST TRACK OF THE HURRICANE ONCE IT MOVES ONSHORE APPEARS TO BE
SOMEWHERE INTO EITHER PA OR NEW YORK STATE THROUGH EARLY NEXT WEEK.
WHILE THERE IS STILL SEVERAL DAYS TO REFINE THE FORECAST...FEEL
INCREASED CONFIDENCE IN THE LIKELIHOOD OF AT LEAST GALES DEVELOPING
LATE MONDAY THROUGH AT LEAST TUESDAY. WITH SOME UNCERTAINTY STILL OF
THE INTENSITY AND TRACK OF THE LOW THROUGH MIDWEEK NEXT WEEK IT IS
UNCLEAR AS TO HOW LONG GALES MAY LINGER...BUT HAVE STRONG CONFIDENCE
THAT AT LEAST SMALL CRAFT CONDITIONS WILL OCCUR ON THE LAKE THROUGH
THE END OF NEXT WEEK.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 AM EDT MONDAY FOR LEZ142>149.
&&
$$
SYNOPSIS...TK
NEAR TERM...REL
SHORT TERM...TK
LONG TERM...ABE
AVIATION...ABE
MARINE...ABE
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
617 AM EDT SAT OCT 27 2012
.SYNOPSIS...
A COLD FRONT OOZES THROUGH THE CENTRAL APPALACHIANS TODAY. SANDY
COMBINES WITH A STRONG UPPER LEVEL SYSTEM TO IMPACT THE AREA SUNDAY
THROUGH MUCH OF NEXT WEEK...WITH WIND AND PROLONGED PRECIPITATION.
&&
.NEAR TERM /THROUGH TONIGHT/...
630 AM UPDATE...
NO CHANGES ALTHOUGH WHAT WAS A SHARP LEADING EDGE OF RAIN W OF OHIO
VALLEY HAS BECOME RAGGED. OVERALL STILL SLOW EWD PROGRESS THOUGH.
PREV DISCN...
EARLY THIS MORNING FINDS A S/W TROUGH OVER THE OHIO VALLEY DRIVING A
COLD FRONT THROUGH THE AREA...AND ADDITIONAL SHORT WAVE ENERGY
DIGGING INTO THE PLAINS BEHIND A L/R MIDWEST TROUGH...ALL WHILE
SANDY IS MOVING SLOWLY N...OUT E OF NORTHERN FL AND N OF THE BAHAMAS.
THE KEY TO THE NEXT 27 HOURS IS THE S/W ROTATION THROUGH THE L/R
TROUGH. THE OHIO VALLEY SHORT LIFTS THROUGH THE EASTERN GREAT LAKES
TODAY AND THEN INTO EASTERN CANADA TONIGHT. THE SURFACE COLD FRONT
NEARING THE WV MOUNTAINS EARLY THIS MORNING SLOWLY OOZES THROUGH
THERE TODAY...AND THEN ACTUALLY GETS ABSORBED INTO THE CIRCULATION
OF SANDY LATER TODAY AND TONIGHT.
THE PRECIPITATION BEHIND THE COLD FRONT MAKES VERY SLOW EWD
PROGRESS...BARELY MAKING IT ACROSS THE OHIO RIVER TODAY. COVERAGE
SHOULD ACTUALLY DIMINISH IN PLACE AS THE FORCING LIFTS OUT THIS
AFTERNOON AND EVENING. OVERNIGHT TONIGHT...THE ADDITIONAL S/W
ENERGY ON THE BACK SIDE OF THE L/R...ESSENTIALLY A SPEED
MAX...CARVES OUT A SHARP...NEGATIVE TILT S/W AS IT ROUNDS THE BASE
OF THE L/R. ITS FORCING INCREASES RAINFALL COVERAGE OVERNIGHT IN A
BAND EITHER SIDE OF THE OHIO RIVER BENEATH A DEFORMATION AXIS
FORMING THERE.
ALSO ADDED DRIZZLE TO THE FORECAST WITH THE PREPONDERANCE OF LOW
LEVEL MOISTURE AND UPSLOPE CONVERGENT LOW LEVEL FLOW.
BLENDED IN HRRR EARLY ON...THEN NAM12 TEMPERATURES AND DEW POINTS TO
BETTER DEPICT THE EVOLUTION OF THE RESPECTIVE GRADIENTS OVER THE
AREA ASSOCIATED WITH THE FRONT MOVING TO THE E. GENERALLY A LITTLE
HIGHER THAN PREVIOUS.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY/...
00Z MODELS IN FAIRLY GOOD AGREEMENT WITH A STALLED AREA OF PRECIP
ALONG THE OHIO RIVER TO START THE SHORT TERM...AND THEN SLOWLY
MERGE THIS INTO THE OVERALL PRECIP SHIELD OF SANDY SUNDAY NIGHT
INTO MONDAY...WITH THE HIGHEST POPS SLIDING INTO THE EASTERN CWA AS
SANDY MAKES LANDFALL. STILL SOME DIFFERENCES IN EXACT LAND
FALL...WITH GFS/NAM SHOWING A CENTRAL/NORTHERN NJ ENTRY POINT...AND
THE ECMWF A BIT SOUTH IN DELMARVA.
NO MATTER THE EXACT LANDFALL...CONFIDENCE CONTINUES TO INCREASE IN A
HIGH PRECIP/HIGH WIND FORECAST...WITH THE GREATEST IMPACTS IN THE
HIGHER TERRAIN WHERE ACCUMULATING UPSLOPE-ENHANCED SNOW AND 40+ KT
WIND GUSTS COULD CREATE QUITE THE WINTER STORM WITH DRIFTING AND LOW
VISIBILITY IN BLOWING SNOW.
INHERITED THE WINTER STORM WATCH...AND AFTER REWORKING THE SNOW
GRIDS DID NOT FEEL CHANGES TO THE HEADLINE WHERE NEEDED AT THIS
TIME. TEMPERATURE ADVECTION...AND ULTIMATELY WHERE THE BEST TEMP
PROFILE FOR SNOW SETS UP...IS KIND OF TRICKY WITH THIS WRAPPED UP
SYSTEM. WILL LIKELY SEE WAA COMING IN ON NORTH WINDS FOR A
TIME...AND THEN POSSIBLY SOME CAA COMING WITH MORE SOUTHWESTERLY
WINDS TOWARDS THE END OF THE SHORT TERM. AM NOT REAL CONFIDENT THAT
THE MODELS HAVE A GOOD HANDLE ON JUST WHERE THE COLDEST MIDLEVEL AIR
WILL BE...OR EVEN HOW COLD IT WILL BE. 00Z GFS/NAM AGREE ON -4C TO
-5C 850 TEMPS BY MONDAY NIGHT...WHILE 00Z ECMWF IS WARMER WITH -1C
TO -2C. THE GFS/NAM WOULD HINT TOWARDS SNOW ACROSS MOST OF THE CWA
BY MONDAY NIGHT...WHILE THE EURO KEEPS IT MORE IN THE MOUNTAINS.
WENT WITH A COMPROMISE...WITH ACCUMULATING SNOW IN THE
MOUNTAINS...AND A RAIN/SNOW MIX CLOSER TO THE OHIO RIVER. EVEN WITH
SOME FLAKES FALLING ACROSS THE LOWLANDS...THINK WITH THE WARM GROUND
ACCUMULATIONS WILL BE TOUGH TO COME BY.
&&
.LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/...
PRIMARY FORECAST CONCERN FOR THIS PERIOD OBVIOUSLY CONTINUES TO
REVOLVE AROUND SANDY/S TRACK AND POTENTIAL IMPACTS FOR THE NORTHEAST
CONUS IN GENERAL...AND SPECIFICALLY POTENTIAL IMPACTS FOR OUR
FORECAST AREA. WITH REGARD TO WHERE SANDY/S LANDFALL...NHC/S TRACK
HAS SHIFTED SOUTHWARD AND NOW BRINGS THE CENTER ASHORE OVER THE
DELMARVA PENINSULA. WITH THE STORM STILL BEING FOUR DAYS AWAY
SIGNIFICANT DIFFERENCES OBVIOUSLY STILL EXIST WITH HOW EXT GUIDANCE
HANDLES SANDY/S TRACK. TO SOME EXTENT EVEN GREATER UNCERTAINTY
EXISTS WITH HOW SANDY/S POST-TROPICAL EVOLUTION TAKES PLACE WITH
STRONG COLD AIR INTRUSION OUT OF THE NORTHWEST...AND THIS WILL HAVE
MAJOR RAMIFICATIONS AS TO THE SNOW/ICE IMPACTS OUR FORECAST AREA
EXPERIENCES AND TO A LESSER EXTENT WIND SPEEDS.
BREAKING DOWN THE SIG DIFFERENCES BETWEEN THE EXT MODELS AND
STARTING WITH THE 00Z EC...SANDY/S CENTER COMES ASHORE OVER DELMARVA
AREA MONDAY AFTERNOON AND SLOWLY MOVES TOWARDS THE EASTERN PANHANDLE
WV AREA BY 12Z TUE. THE SFC CENTER FILLS RAPIDLY BY TUESDAY MORNING
AS WELL WITH A SFC PRESS OF 982MB BY SAME TIME WITH WARM ADVECTION
WRAPPING AROUND THE BACKSIDE. THIS SCENARIO WOULD LIKELY MEAN MUCH
HIGHER PRECIP AMOUNTS FOR THE OVERALL AREA BUT WOULD ALSO MEAN A
LESSER LIKELIHOOD OF ACCUM SNOWFALL FOR LOWER ELEVATIONS AS THE
540DAM THICKNESS HEIGHT LINE REMAINS GENERALLY ALONG AND WEST OF OUR
FORECAST AREA. HIGH RAINFALL AMOUNTS BECOME THE BIGGER ISSUE WITH
THIS SCENARIO FOR LOWLANDS WITH A GENERAL 2-4 INCHES OF QPF DEPICTED
WITH HIGHER AMOUNTS CERTAINLY POSSIBLE.
MEANWHILE THE 12Z GFS CONTINUES TO BRING SANDY/S CENTER ASHORE NEAR
NYC TUES AFTERNOON WITH A SW RETROGRADE NEAR PHILLY BY TUE
EVE...BEFORE KICKING IT OUT TO THE N/NW WEDNESDAY. THIS SCENARIO
BRINGS A LONGER WIND EVENT CONTINUING WELL INTO TUE WITH THE SFC LOW
FARTHER AWAY. THIS SCENARIO ALSO ALLOWS COLDER AIR INTO THE
AREA...WITH THE 540DAM LINE COMPLETELY ENCOMPASSING AND WELL SOUTH
OF THE FORECAST AREA. THIS SCENARIO WOULD SPELL SNOWFALL FOR LOWLAND
LOCATIONS AS WELL. EVEN SO...WITH WARM SFC TEMPS FROM A WEEK OF VERY
WARM WEATHER IT WOULD PROBABLY TAKE SOME TIME BEFORE SNOW BEGINS TO
ACCUM ON ROADWAYS.
WITH ALL THIS IN MIND...WILL SIDE THE FORECAST TOWARDS THE EC WHICH
IS MUCH CLOSER TO NHC/S CURRENT TRACK AND THUS WILL LEAN THE
EVOLUTION OF THE SYSTEM IN THIS DIRECTION AS WELL. EITHER
WAY...THOUGH THE BEGINNING OF THE EVENT IS STILL 2-3 DAYS OUT
CONFIDENCE IS GROWING WITH A SIGNIFICANT SNOWFALL EVENT FOR THE HIGH
COUNTRY...PARTICULARLY FOR THE HIGHEST LOCATIONS SUCH AS SNOWSHOE.
IN COORDINATION WITH THE SHORT TERM FORECASTER...WILL KEEP WINTER
STORM WATCH FOR THESE AREAS GOING THROUGH 00Z WED WITH THE LONG
DURATION POTENTIAL. ACROSS THE LOWLANDS AMOUNTS GENERALLY UNDER TWO
INCHES ARE EXPECTED FOR WV ZONES...WITH MUCH OF IT COMING DURING THE
OVERNIGHT HOURS WITH PRIMARILY RAIN DURING THE DAY. LITTLE SNOW
SHOULD ACCUMULATE ON ROAD SURFACES WITH SUCH VERY WARM TEMPS IN
PLACE THIS WEEK. HAVE ALSO LOWERED MAX TEMPS TUESDAY AND WEDNESDAY.
AGAIN...STILL A GOOD DEAL OF UNCERTAINTY WITH THE FINAL TRACK AND
ANY SHIFT NORTH OR SOUTH COULD MAKE SUBSTANTIAL DIFFERENCES IN
RAIN/SNOW AMOUNTS RECEIVED AND WHERE...SNOW ACCUMULATIONS...ALONG
WITH WINDS.
&&
.AVIATION /10Z SATURDAY THROUGH WEDNESDAY/...
MVFR CIGS OOZING E ACROSS AREA TODAY WILL THEN HANG AROUND THROUGH
THE BALANCE OF THE PERIOD...WITH OCCASIONAL IFR CIGS. RAIN SHOWERS
WILL BE MOST PREVALENT NEAR THE OHIO RIVER...WITH MVFR VSBY AT TIMES
THERE.
SURFACE FRONT WILL CROSS THE MOUNTAINS FIRST THING THIS
MORNING...WITH LIGHT SE FLOW AHEAD OF IT. OTHERWISE LIGHT N TO NW
SURFACE FLOW BEHIND THE FRONT WILL FRESHEN A BIT TODAY AND THEN
REMAIN NEAR 10 KTS MOST LOCALES TONIGHT...A BIT GUSTY ON THE
RIDGES. FRONT ALOFT WILL ENTER WESTERN WV THIS AFTERNOON AND THEN
STALL THERE. LIGHT N TO NE FLOW BEHIND THE FRONT WILL BE MODERATE N
TO NE THIS AFTERNOON AND TONIGHT. AHEAD OF THE FRONT ALOFT...LIGHT
S FLOW TODAY WILL BECOME LIGHT E TO NE LATE TODAY AND TONIGHT.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z SUNDAY...
FORECAST CONFIDENCE: MEDIUM HIGH.
ALTERNATE SCENARIOS: TIMING...PERSISTENCE AND EXTENT OF IFR CIGS AND
MVFR VSBYS MAY VARY.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
DATE SAT 10/27/12
UTC 1HRLY 08 09 10 11 12 13 14 15 16 17 18 19
EDT 1HRLY 04 05 06 07 08 09 10 11 12 13 14 15
CRW CONSISTENCY M M M M M M M M H H H H
HTS CONSISTENCY H M M H H H H H H H H H
BKW CONSISTENCY L L L L L L H H H H H H
EKN CONSISTENCY H M M H H H H H H H H H
PKB CONSISTENCY H H H H H H H H H H M H
CKB CONSISTENCY M M M M M M H H H H H H
AFTER 12Z SUNDAY...
IFR POSSIBLE IN RAIN AND SNOW SHOWERS WITH REMNANTS OF SANDY EARLY
NEXT WEEK. RAIN WILL BE THE DOMINANT PRECIPITATION TYPE OVER THE
LOW TERRAIN...WITH SNOW PREDOMINANT ACROSS THE HIGHER TERRAIN. THE
PRECIPITATION WILL TEND TO BE MORE IN THE FORM OF RAIN DURING THE
DAY...WHEN MOST OF WHAT IS SNOW IS WET SNOW. FOR THE OTHERWISE RAIN
DOMINATED LOWLANDS...WET SNOW IS POSSIBLE AT NT.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...WINTER STORM WATCH FROM LATE SUNDAY NIGHT THROUGH TUESDAY
EVENING FOR WVZ038-046-047.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...TRM
NEAR TERM...TRM
SHORT TERM...MZ
LONG TERM...50
AVIATION...TRM
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
540 AM CDT SAT OCT 27 2012
.SHORT TERM...TODAY THROUGH MONDAY NIGHT
231 AM CDT SAT OCT 27 2012
MAIN FORECAST CONCERNS ARE ON CLOUDS AND TEMPERATURES THROUGHOUT DUE
TO LACK OF PRECIPITATION FORCING MECHANISMS.
CURRENTLY AS OF 07Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
LOOKS VERY SIMILAR TO 24 HOURS AGO WITH RIDGING OVER THE EASTERN
PACIFIC...TROUGHING OVER THE WESTERN TWO THIRDS OF CANADA INTO THE
SOUTHERN PLAINS...RIDGING OVER NEWFOUNDLAND AND TROPICAL STORM SANDY
SITTING JUST NORTH OF THE NORTHWEST BAHAMAS. MAIN SHORTWAVE OF NOTE
WAS OVER SOUTHERN BRITISH COLUMBIA WITH A 130 KT JET STREAK NEAR
225MB IN EASTERN WASHINGTON STATE. A STREAM OF CIRRUS EXTENDED
DOWNSTREAM FROM THIS SHORTWAVE INTO MONTANA AND THE WESTERN DAKOTAS.
FARTHER EAST INTO THE FORECAST AREA...A BROKEN FIELD OF
STRATOCUMULUS COVERED MUCH OF THE UPPER MISSISSIPPI RIVER VALLEY
REGION. THESE CLOUDS WERE REPRESENTED WELL ON THE 00Z MPX SOUNDING
BY YET ANOTHER MOIST LAYER BETWEEN 750-800MB. AIRMASS REMAINS COOL
OVER THE FORECAST AREA WITH 00Z SOUNDINGS SHOWING 850MB TEMPS AROUND
-7C. HOWEVER...THE CLOUDS AND A LIGHT WESTERLY BREEZE NORTH OF HIGH
PRESSURE IN WESTERN IOWA HAVE HELPED TO LIMIT THE TEMPERATURE FALL
TOO MUCH THUS FAR. TEMPERATURES SO FAR HAVE FALLEN INTO THE UPPER
20S TO MID 30S.
TODAY THROUGH SUNDAY...FOCUS FOR OUR AREA IS ON THAT SHORTWAVE IN
SOUTHERN BRITISH COLUMBIA. MODELS ARE IN GOOD AGREEMENT DROPPING IT
DOWN INTO THE BASE OF THE UPPER TROUGH...REACHING FAR WESTERN
NEBRASKA BY 00Z SUNDAY...THE MEMPHIS TN AREA BY 12Z SUNDAY AND THEN
PUSHING EAST TO THE GREAT SMOKY MOUNTAINS AREA BY 00Z MONDAY. AS
THIS SHORTWAVE DIVES SOUTHEAST...EXPECT THE MASS OF CIRRUS ENTERING
THE DAKOTAS TO SPREAD INTO THE FORECAST AREA THIS AFTERNOON AND
EVENING. THUS...EVEN IF THE CURRENT STRATOCUMULUS CONTINUES TO BREAK
UP OR DISSIPATE...THE CLEARING LOOKS TO BE TEMPORARY. THE CIRRUS
APPEARS TO HOLD ON THROUGH MUCH OF TONIGHT...THEN THERE ARE
SUGGESTIONS OF A DECAYING MID CLOUD DECK ASSOCIATED WITH THE
SHORTWAVE MOVING INTO THE AREA FROM THE WEST ON SUNDAY. PLENTY OF
LOW LEVEL DRY AIR AND LACK OF FORCING WILL KEEP THE FORECAST AREA
DRY. HOWEVER...THE CLOUDS ARE LIKELY TO MAKE AN IMPACT ON
TEMPERATURE FORECASTS. BEING IN UPPER TROUGHING AND THE LOW SUN
ANGLE THIS TIME OF YEAR...THE 850MB TEMPS AND GENERAL AIRMASS ARE
GOING TO HAVE A TOUGH TIME WARMING. IN FACT...THE READINGS CHANGE
VERY LITTLE...CLIMBING FROM -6 TO -8C TODAY TO -4 TO -6C ON SUNDAY.
WITH CLOUDS AROUND...ANTICIPATING HIGHS TO STAY STUCK IN THE LOWER
TO MID 40S. THE CIRRUS DECK AND INCOMING MID CLOUDS SHOULD HELP TO
KEEP TEMPERATURES UP TONIGHT...IN THE UPPER 20S TO LOW 30S.
SUNDAY NIGHT THROUGH MONDAY NIGHT...MUCH OF THE ACTION IS EXPECTED
IN THE MID-ATLANTIC AND NORTHEAST U.S. DURING THIS PERIOD...IN
RESPONSE TO INTERACTION AND PHASING OF SANDY WITH THE CURRENT
BRITISH COLUMBIA SHORTWAVE...RELEASE OF LATENT HEAT AND A COUPLING
OF SUBTROPICAL AND POLAR JETS. THE NET RESULT BY 12Z TUESDAY FROM
ALL MODELS IS A DEEP UPPER TROUGH ENCOMPASSING MUCH OF THE EASTERN
U.S. WITH A DEEP POST-TROPICAL SANDY SITUATED IN OR NEAR PENNSYLVANIA.
MEANWHILE...UPPER RIDGING THAT HAS BEEN OVER THE EAST PACIFIC
MODELS HAVE BUILDING ACROSS THE WESTERN U.S. AND INTO THE WESTERN
PLAINS. THIS SETUP EFFECTIVELY BLOCKS ANY PRECIPITATION FROM
ENTERING THE PICTURE FOR OUR AREA. IN FACT...HIGH PRESSURE SHOULD
DOMINATE AT THE SURFACE THROUGH MUCH OF THE TIME PERIOD.
TEMPERATURES LOOK TO STAY COOL DUE TO 850MB TEMPS STILL ONLY
WARMING SLOWLY TO -1 TO -4C ON MONDAY. CLOUD COVER WISE...THERE
ARE HINTS OF SOME WARM ADVECTION MID CLOUDS COMING INTO WESTERN
SECTIONS OF THE AREA ON MONDAY...BUT THEN THESE GET SHUNTED
SOUTHWEST BY SUBSIDENCE ON THE BACK SIDE OF THE DEEP EASTERN
TROUGH.
.LONG TERM...TUESDAY THROUGH FRIDAY NIGHT
231 AM CDT SAT OCT 27 2012
FOCUS FOR THE EARLY PORTION OF THE LONG TERM PERIOD IS THE DEEP
EASTERN U.S. UPPER TROUGH AND POST-TROPICAL SANDY INSIDE OF THE
TROUGH. 27.00Z ECMWF/GFS/CANADIAN/UKMET AND GFS ENSEMBLES ARE IN
VERY GOOD AGREEMENT THAT THE DEEP UPPER TROUGH WILL BE BLOCKED
BETWEEN RIDGING OVER THE WESTERN U.S....STRONG UPPER RIDGING NEAR
NEWFOUNDLAND AND PERHAPS EVEN RIDGING CONNECTING THESE TWO. AS
SUCH...THE MODELS TAKE AWHILE BEFORE LIFTING THE EASTERN TROUGH OUT.
IT MAY NOT BE UNTIL SOMETIME THURSDAY NIGHT OR FRIDAY BEFORE THE
EJECTION OCCURS. WITH THE EASTERN TROUGH BLOCKED FROM MOVING
MUCH...THE FORECAST AREA STAYS ON THE SUBSIDENT SIDE THROUGH AT
LEAST THURSDAY...MOSTLY PREVENTING PRECIPITATION. ONE CONCERN WOULD
BE DEFORMATION PRECIPITATION ASSOCIATED WITH POST-TROPICAL SANDY
RETROGRADING SLOLWY WESTWARD TOWARDS THE AREA TUESDAY INTO
WEDNESDAY. HOWEVER...MOST MODELS SUGGESTS THIS DEFORMATION BAND
WILL STAY EAST OF THE AREA...PERHAPS MAKING IT AS FAR WEST AS
EASTERN WISCONSIN. LOOKS LIKE WE WILL SEE A NORTHERLY BREEZE
INCREASE FOR TUESDAY AND PERHAPS WEDNESDAY TOO...PARTICULARLY
ACROSS WISCONSIN. FOR FRIDAY...GOOD MODEL CONSENSUS EXISTS FOR
SUBTROPICAL UPPER RIDGING TO CROSS THE CENTRAL AND SOUTHERN PLAINS
AHEAD OF A TROUGH CROSSING COLORADO. ANY WARM ADVECTION
PRECIPITATION ASSOCIATED WITH THE RIDGE LOOKS TO STAY TO THE SOUTH
AT THE PRESENT TIME...THOUGH AN INCREASE IN MID/HIGH CLOUDS SHOULD
OCCUR.
TEMPERATURES WILL GRADUALLY WARM THROUGH THE LONG TERM PERIOD...
ESPECIALLY TOWARDS THE END OF THE WEEK AS THE EASTERN UPPER TROUGH
LIFTS OUT. BY THURSDAY...READINGS SHOULD BE BACK TO NEAR NORMAL.
&&
.AVIATION...TODAY AND TONIGHT
540 AM CDT SAT OCT 27 2012
PLAN ON VFR CONDITIONS THROUGH TONIGHT. IR/SURFACE OBSERVATIONS
SHOWING PESKY STRATOCUMULUS IN THE 5-6KFT RANGE BECOMING MORE
PATCHY IN NATURE DUE TO HIGH PRESSURE BUILDING IN FROM THE PLAINS.
GOING WITH SCT050 TODAY AT BOTH KLSE/KRST THROUGH 23Z. AN UPPER
LEVEL DISTURBANCE/MID-LEVEL TROUGH MOVING ACROSS THE DAKOTAS
TONIGHT WILL THEN BRING LOWERING ALTOCUMULUS/ALTOSTRATUS CLOUDS
INTO THE AREA THROUGH THE OVERNIGHT HOURS. EXPECTING LOWEST
CEILING SOMEWHERE IN THE 7-10KFT RANGE THROUGH 12Z. THE MID-LEVEL
TROUGH WILL THEN LIFT NORTH OF THE AREA SUNDAY...BRINGING BULK OF
ALTOCUMULUS/ALTOSTRATUS CLOUD WITH IT. WINDS THROUGH TONIGHT ARE
EXPECTED TO REMAIN AROUND 5KT OR LESS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
231 AM CDT SAT OCT 27 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...DAS
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
500 PM EDT SAT OCT 27 2012
.SYNOPSIS...
TROPICAL SYSTEM SANDY CONTINUES TO MOVE NORTH OFFSHORE TONIGHT
AND SUNDAY. THE PRESSURE GRADIENT ASSOCIATED WITH THE SYSTEM WILL
RESULT IN BREEZY CONDITIONS IN THE FORECAST AREA. MOST OF THE RAIN
ASSOCIATED WITH SANDY WILL REMAIN NEAR THE COAST. AN APPROACHING
COLD FRONT WILL MOVE THROUGH THE AREA SUNDAY. THE COLDEST AIR OF
THE SEASON SO FAR WILL FOLLOW THIS FRONT.
&&
.NEAR TERM /TONIGHT/...
REGIONAL RADARS CONTINUE TO SHOW THE PRECIP ASSOCIATED WITH
SANDY REMAINING GENERALLY RIGHT ALONG THE COAST...THEN EXTENDING
OFFSHORE. THE SHOWERS ARE FORECAST TO REMAIN WELL TO THE EAST...SO
HAVE GONE WITH A DRY FORECAST OVERNIGHT FOR ALL AREAS. BIGGEST
ISSUE TONIGHT WILL REVOLVE AROUND THE WINDS. SURFACE OBSERVATIONS
FROM AREA SITES STILL SHOWING WINDS 10 TO 15 MPH ACROSS THE
WEST...AND 15-20 MPH WITH GUSTS TO 30 MPH ACROSS THE EAST. WOULD
EXPECT THIS WIND FIELD TO DOMINATE ALL NIGHT. HAVE ADJUSTED WINDS
TO BETTER ACCOUNT FOR CURRENT CONDITIONS...AND TWEAKED WINDS FOR
THE OVERNIGHT PERIOD. DUE TO THE STRONG WINDS...THE LAKE WIND
ADVISORY REMAINS IN EFFECT THROUGH THE NIGHT. MOS LOW TEMPERATURE
GUIDANCE WITH LOWS IN THE LOWER 50S STILL OK.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
THE NAM AND GFS CONTINUE TO SHOW DEEP MOISTURE REMAINING
NORTHEAST OF THE FORECAST AREA AS SANDY MOVES NORTH-NORTHEASTWARD.
THE COLD FRONT SUNDAY STILL APPEARS DRY BECAUSE OF A LACK OF
SIGNIFICANT CONVERGENCE. THE PRESSURE GRADIENT WILL CONTINUE TO
SUPPORT BREEZY CONDITIONS AND WE HAVE MAINTAINED THE LAKE WIND
ADVISORY INTO SUNDAY NIGHT. MODEL GUIDANCE CONSENSUS STILL LOOKED
GOOD FOR THE TEMPERATURE FORECAST.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
STRONG LOW PRESSURE IN THE MIDDLE ATLANTIC AND NORTHEAST STATES
AND RIDGING IN THE MIDDLE OF THE NATION WILL MAINTAIN NORTHWEST
FLOW INTO THE FORECAST AREA DURING THE EXTENDED PERIOD. IT WILL BE
A DRY AND COOL PERIOD. MOSTLY CLEAR SKIES EXCEPT FOR TUESDAY AS
MODELS BRING A DECENT SHORT WAVE AND CLOUDS TO THE REGION. DECIDED
TO USE A MODEL BLEND WITH HIGHS ONLY IN THE LOWER 50S FOR TUESDAY.
OTHERWISE...THE GFS ENSEMBLE MEANS SUPPORT LOWS IN THE 30S.
&&
.AVIATION /21Z SATURDAY THROUGH THURSDAY/...
VFR EXPECTED THROUGH THE 24 HOUR TAF PERIOD WITH BREEZY CONDITIONS.
THE CENTER OF HURRICANE SANDY IS OVER THE OFFSHORE ATLANTIC WATERS
ABOUT 400 MILES SE OF CAE...PROVIDING OUR FA WITH BREEZY NNE WINDS AND
A BLANKET OF HIGH LEVEL CLOUDINESS. ASSOCIATED RAIN AREAS ARE ALONG
THE COAST. NEARLY STATIONARY COLD FRONT TO OUR NW BANKED UP AGAINST
THE MOUNTAINS. SANDY IS FORECAST TO CONTINUE MOVING TO THE NE...WITH
ASSOCIATED RAIN REMAINING EAST OF THE TERMINALS. LOWER MVFR CIGS ARE
CURRENTLY ALONG THE COASTAL PLAIN...PEE DEE...AND E NC. AS SANDY
TRACKS TO THE NE...MODEL PROJECT LOW LEVEL FLOW OVER OUR FA TO BACK
SLIGHTLY FROM NNE TO MORE OF A N TO NNW. THIS WILL WORK TO KEEP
LOWER MVFR CIGS JUST EAST OF THE TERMINALS...PER LATEST RAP GUIDANCE.
EXTENDED AVIATION OUTLOOK...BREEZY CONDITIONS MAY CONTINUE THROUGH
TUESDAY...OTHERWISE NO MAJOR RESTRICTIONS FOR AVIATION INTERESTS
EXPECTED.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...LAKE WIND ADVISORY UNTIL 10 PM EDT SUNDAY FOR SCZ015-016-018-
020>022-025>031-035>038-041.
GA...LAKE WIND ADVISORY UNTIL 10 PM EDT SUNDAY FOR GAZ040-063>065-
077.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
419 PM EDT SAT OCT 27 2012
.SYNOPSIS...
TROPICAL SYSTEM SANDY CONTINUES TO MOVE NORTH OFFSHORE TONIGHT
AND SUNDAY. THE PRESSURE GRADIENT ASSOCIATED WITH THE SYSTEM WILL
RESULT IN BREEZY CONDITIONS IN THE FORECAST AREA. MOST OF THE RAIN
ASSOCIATED WITH SANDY WILL REMAIN NEAR THE COAST. AN APPROACHING
COLD FRONT WILL MOVE THROUGH THE AREA SUNDAY. THE COLDEST AIR OF
THE SEASON SO FAR WILL FOLLOW THIS FRONT.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
LOCAL AREA RADARS SHOW THAT PRECIPITATION ON THE WESTERN FRINGES
OF SANDY ARE LOCATED ALONG THE COAST AS THE MODELS HAVE BEEN
INDICATING. IT LOOKS LIKE THE SHOWERS WILL REMAIN MAINLY WELL TO
THE EAST. WILL JUST HAVE A SLIGHT CHANCE IN THE FAR EASTERN
COUNTIES. OBS FROM AREA SITES STILL HAVE WINDS 15-20 MPH WITH
GUSTS TO 30-35 MPH. MOS LOW TEMPERATURE GUIDANCE WITH LOWS IN
THE LOWER 50S STILL OK.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/...
THE NAM AND GFS CONTINUE TO SHOW DEEP MOISTURE REMAINING NORTHEAST
OF THE FORECAST AREA AS SANDY MOVES NORTH-NORTHEASTWARD. THE COLD
FRONT SUNDAY STILL APPEARS DRY BECAUSE OF A LACK OF SIGNIFICANT
CONVERGENCE. THE PRESSURE GRADIENT WILL CONTINUE TO SUPPORT BREEZY
CONDITIONS AND WE HAVE MAINTAINED THE LAKE WIND ADVISORY. MODEL
GUIDANCE CONSENSUS STILL LOOKED GOOD FOR THE TEMPERATURE FORECAST.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
STRONG LOW PRESSURE IN THE MIDDLE ATLANTIC AND NORTHEAST STATES
AND RIDGING IN THE MIDDLE OF THE NATION WILL MAINTAIN NORTHWEST
FLOW INTO THE FORECAST AREA DURING THE EXTENDED PERIOD. IT WILL BE
A DRY AND COOL PERIOD. MOSTLY CLEAR SKIES EXCEPT FOR TUESDAY AS
MODELS BRING A DECENT SHORT WAVE AND CLOUDS TO THE REGION. DECIDED
TO USE A MODEL BLEND WITH HIGHS ONLY IN THE LOWER 50S FOR TUESDAY.
OTHERWISE...THE GFS ENSEMBLE MEANS SUPPORT LOWS IN THE 30S.
&&
.AVIATION /20Z SATURDAY THROUGH THURSDAY/...
VFR EXPECTED THROUGH THE 24 HOUR TAF PERIOD WITH BREEZY CONDITIONS.
THE CENTER OF HURRICANE SANDY IS OVER THE OFFSHORE ATLANTIC WATERS
ABOUT 400 MILES SE OF CAE...PROVIDING OUR FA WITH BREEZY NNE WINDS AND
A BLANKET OF HIGH LEVEL CLOUDINESS. ASSOCIATED RAIN AREAS ARE ALONG
THE COAST. NEARLY STATIONARY COLD FRONT TO OUR NW BANKED UP AGAINST
THE MOUNTAINS. SANDY IS FORECAST TO CONTINUE MOVING TO THE NE...WITH
ASSOCIATED RAIN REMAINING EAST OF THE TERMINALS. LOWER MVFR CIGS ARE
CURRENTLY ALONG THE COASTAL PLAIN...PEE DEE...AND E NC. AS SANDY
TRACKS TO THE NE...MODEL PROJECT LOW LEVEL FLOW OVER OUR FA TO BACK
SLIGHTLY FROM NNE TO MORE OF A N TO NNW. THIS WILL WORK TO KEEP
LOWER MVFR CIGS JUST EAST OF THE TERMINALS...PER LATEST RAP GUIDANCE.
EXTENDED AVIATION OUTLOOK...BREEZY CONDITIONS MAY CONTINUE THROUGH
TUESDAY...OTHERWISE NO MAJOR RESTRICTIONS FOR AVIATION INTERESTS
EXPECTED.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...LAKE WIND ADVISORY UNTIL 10 PM EDT SUNDAY FOR SCZ015-016-018-
020>022-025>031-035>038-041.
GA...LAKE WIND ADVISORY UNTIL 10 PM EDT SUNDAY FOR GAZ040-063>065-
077.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
501 PM CDT SAT OCT 27 2012
.DISCUSSION...
330 PM CDT
MAIN FORECAST CONCERNS/CHALLENGES ARE WITH PERSISTENT LAKE EFFECT
CLOUD COVER AND LIGHT SHOWERS WITH COOL DRY CONDITIONS EXPECTED
FOR THE REMAINDER OF THE CWA...WITH EVENTUALLY OUR WEATHER TO BE
DICTATED BY LARGE SCALE PATTERN OWING TO SANDY.
WITH THE LAKE EFFECT CLOUD COVER AND ISOLATED LIGHT SHOWERS
AFFECTING AREAS NEAR THE LAKE IN NORTHWEST INDIANA AND EVENTUALLY
NORTHEAST ILLINOIS TONIGHT...HAVE MADE ONLY MINOR TWEAKS TO THE
POP/WX THROUGH THE REMAINDER OF THE WEEKEND. LATEST SATELLITE
IMAGERY STILL DEPICTING AXIS OF CONVERGENCE ALONG THE EASTERN SIDE
OF THE LAKE AS WELL AS WITH BOTH SURFACE OBS AND RAP ANALYSIS
PAINTING A SIMILAR PICTURE. ALTHOUGH...THIS AXIS OF CONVERGENCE
HAS WEAKENED SOMEWHAT EARLY THIS AFTERNOON WITH THE LOSS OF
SYNOPTIC AND LAND BREEZE INTERACTION...WITH DIURNAL TRENDS AIDING
FOR MORE SYNOPTIC NORTH TO NORTHWEST FLOW ALONG THE EASTERN
PORTIONS OF THE LAKE. NONETHELESS...WITH SUFFICIENT DELTA TS AND
WEAK CONVERGENCE...CLOUD COVER CONTINUES TO DEVELOP AND SPILL
INLAND THIS AFTERNOON. HAD MAINTAINED ISOLATED LIGHT SHOWERS FOR
AREAS ACROSS THE SOUTHEAST PORTION OF THE LAKE AND PORTER COUNTY
WHERE BETTER CONVERGENCE RESIDED...BUT HAVE NOT SEEN MUCH
DEVELOPMENT IF ANY AT ALL THIS AFTERNOON. ALTHOUGH...COULD NOT
RULE OUT SOME SPRINKLES OR LIGHT SHOWERS TO DEVELOP UNDER THIS
BEST AXIS OF CONVERGENCE THROUGH THE REMAINDER OF THE AFTERNOON.
CURRENT SHORT WAVE TROUGH OVER THE ROCKIES/PLAINS WILL QUICKLY
WORK ITS WAY EAST/SOUTHEAST...AS THE LARGE UPPER LEVEL TROUGH DIGS
SOUTH ACROSS THE REGION TONIGHT. AS THIS OCCURS...LOW LEVEL FLOW
WILL RESPOND AND SHIFT MORE NORTHERLY/NORTHEASTERLY. THIS SHIFT IN
FLOW WILL BRING THIS CONVERGENT AXIS WEST ORIENTING ITSELF SUCH
THAT I EXPECT CURRENT CLOUD COVER TO BEGIN SPILLING ONTO NORTHEAST
ILLINOIS. THE PRESENCE OF SIMILAR DELTA TS WITH ONCE
AGAIN...INCREASING LOW LEVEL CONVERGENCE TONIGHT...EXPECT LAKE
EFFECT CLOUD COVER TO PERSIST WITH SLIGHTLY BETTER CHANCES FOR
SOME ISOLATED LIGHT SHOWERS. A LONGER FETCH EXTENDING FROM THE FAR
NORTHERN PORTIONS OF THE LAKE SHOULD AID IN A BETTER ENVIRONMENT
FOR THIS LIGHT PRECIP TO DEVELOP. HIRES DATA DOES SUPPORT THIS
SCENARIO WITH GUIDANCE SHOWING A NARROW AXIS DEVELOPING FROM MID
LAKE AND THEN EXTENDING SOUTHWEST INTO FAR NORTHEAST ILLINOIS AND
FAR NORTHWEST INDIANA. WITH PREVIOUSLY MENTIONED CONDITIONS IN
PLACE...CANNOT REALLY ARGUE THIS POSSIBILITY. ALTHOUGH...I WONDER
HOW MUCH MOISTURE WILL BE AVAILABLE FOR THIS WEAK FORCING TO WORK
WITH. THIS WILL OF COURSE PLAY A BIG PART WITH OVERALL
DEVELOPMENT...BUT MORE IMPORTANTLY COVERAGE. HAVE TRIED TO ADD
SOME ADDED DETAIL TO THE POP/WX GRID TRYING TO SHOW A MORE NARROW
AXIS OF DEVELOPMENT....KEEPING ISOLATED LIGHT SHOWERS TONIGHT AS
WELL AS FOR MOST OF SUNDAY. ALTHOUGH THIS LIGHT PRECIP WILL BE
SOMEWHAT IN QUESTION...CLOUD COVER WILL NOT AND SHOULD SPAN MOST
OF NORTHEAST ILLINOIS AND NORTHWEST INDIANA LATE TONIGHT INTO
SUNDAY. EXPECT BOUNDARY LAYER FLOW THEN TO SHIFT MORE NORTHERLY
SUNDAY NIGHT INTO MONDAY WITH THIS CLOUD COVER AND ISOLATED
SHOWERS TO SHIFT BACK PRIMARILY INTO NORTHWEST INDIANA. MOISTURE
WILL THEN BE LACKING GOING INTO MONDAY...WITH PRECIP REALLY NOT
BECOMING LIKELY.
DRY CONDITIONS WILL TAKE PLACE FOR THE ENTIRE CWA MONDAY NIGHT
AND THROUGH MOST OF TUESDAY...AS SIGNIFICANT LARGE SCALE
INTERACTION WILL TAKE PLACE ACROSS THE EAST COAST. THIS CURRENT
LARGE SCALE TROUGH OVERHEAD WILL EVENTUALLY INTERACT WITH SANDY
OVER THE EAST COAST DURING THE START OF NEXT WEEK. WHAT THIS WILL
MEAN FOR AREAS IN OUR LOCATION...IS A LARGE STRONG UPPER LEVEL
SYSTEM THAT WILL SPAN MUCH OF THE EASTERN HALF OF THE US. MOISTURE
WRAPPING AROUND THIS SYSTEM WILL THEN WORK ITS WAY NEAR THE CWA
BUT PRIMARILY OVER THE EASTERN PORTION OF LAKE MICHIGAN THROUGH
MID WEEK. ALTHOUGH THERE IS STILL SOME UNCERTAINTY AS TO THE
OVERALL EVOLUTION WITH THIS LARGE SYSTEM AS WELL AS
MOISTURE/PRECIP REACHING THE CWA...IT DOES APPEAR AS THE BEST AXIS
OF PRECIP SHOULD STAY EAST. WHAT IS NOT IN QUESTION MONDAY THROUGH
WEDNESDAY IS THE STRONG NORTHERLY FLOW THAT WILL TAKE PLACE OVER
THE CWA AND MORE IMPORTANTLY OVER THE LAKE. THIS STRONG FLOW WILL
BRING LARGE WAVES CRASHING SOUTH OVER THE SOUTHERN END OF THE LAKE
AND ONTO AREAS NEAR THE LAKE...WITH HIGH WAVES ON BOTH THE
ILLINOIS AND INDIANA NEARSHORE WATERS EXPECTED BUT WITH THE
HIGHEST WAVES EXPECTED OVER INDIANA. WILL CONTINUE TO WATCH THIS
SITUATION CLOSELY AS HIGH WINDS AND EVEN SOME LAKE SHORE FLOODING
COULD EVENTUALLY BE ISSUES FOR AREAS IMMEDIATELY NEAR THE LAKE.
RODRIGUEZ
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 22Z...
* NE WINDS WITH OCCASIONAL GUSTS 15 TO 18 KT THE REST OF THIS
AFTERNOON.
* LAKE INDUCED MVFR CIGS DEVELOPING LATER TONIGHT AND PERSISTING
INTO SUNDAY MORNING.
RATZER/MTF
//DISCUSSION...UPDATED 18Z...
HIGH PRESSURE REMAINS AND WILL REMAIN PARKED FROM KANSAS CITY TO
SOUTHWEST WI. THIS WILL RESULT IN CONTINUED NORTHERLY FLOW ACROSS
THE AREA. SIMILAR WIND CONDITIONS AS OBSERVED YESTERDAY ARE
PRESENT THIS AFTERNOON...SO DO EXPECT AND ALREADY HAVE SEEN TO
SOME DEGREE LAKE INFLUENCE MOVING INTO THE CHICAGOLAND TAF SITES.
THIS SHOULD HELP SHIFT THE WINDS AT ORD AND MDW TO THE NE. THE
COOLER FLOW OVER THE LAKE HAS RESULTED IN BKN 030-040 CIGS JUST
EAST OF MDW INTO NW IN. THE CONVERGENT AXIS FAVORING THE CLOUDS IN
THESE LOCATIONS IS LIKELY TO GENERALLY HOLD IN PLACE THROUGH THE
REST OF THIS AFTERNOON BEFORE SHIFTING TO THE WEST ACROSS CHICAGO
LATE TONIGHT INTO SUNDAY. A LONGER FETCH OVER THE LAKE SHOULD
RESULT IN BKN TO OVC CLOUDS FOR THE CHICAGO AIRPORTS SUNDAY
MORNING...AND LIKELY TO BE IN THE MVFR CATEGORY FOR THOSE
AIRFIELDS CLOSER TO THE LAKE SHORE. WITH THE SYNOPTIC FLOW
BECOMING MORE NE...GUSTS SHOULD CONTINUE ON SUNDAY THE FLOW OFF
THE FRICTIONLESS LAKE.
//ORD AND MDW CONFIDENCE...UPDATED 22Z...
* HIGH CONFIDENCE IN WINDS REMAINING NNE TO NE THROUGH REMAINDER
OF AFTERNOON...LIKELY BACKING NNW WITH SLIGHT LAND BREEZE
DEVELOPMENT LATER THIS EVENING.
* HIGH CONFIDENCE IN 2500-4000 FT CIGS LATE TONIGHT AND SUNDAY
MORNING. THESE MAY END UP BEING LOWER...BUT HIGH CONFIDENCE THEY
WILL REMAIN ABOVE 1500 FT.
RATZER/MTF
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT AND MONDAY...GENERALLY VFR. SMALL THREAT OF LOCALIZED
LAKE EFFECT MVFR CIGS AND SLIGHT CHANCE OF SHRA.
TUESDAY THROUGH THURSDAY...GENERALLY VFR. LOW PROBABILITY OF
LOCALIZED SHOWERS TUES-WED. BREEZY FROM THE NNW.
FRIDAY...VFR.
MTF
&&
.MARINE...
423 PM CDT
HIGH PRESSURE HAS MOVED OVER THE NORTHERN MISSISSIPPI RIVER VALLEY
THIS AFTERNOON AND THE AXIS OF THE SURFACE RIDGE WILL REMAIN
CENTERED JUST WEST OF LAKE MICHIGAN THROUGH MID NEXT WEEK. NORTH
WINDS ARE ALSO EXPECTED THROUGH MID NEXT WEEK. AS SUCH...CONTINUED
THE SMALL CRAFT ADVISORY FOR HIGH WAVES. WINDS WILL ALSO PICK UP
TO 20 TO 25 KT TONIGHT.
THE REMNANTS OF HURRICANE SANDY MOVE ASHORE LATE MONDAY INTO MONDAY
NIGHT AND GUIDANCE DIFFERS ON HOW FAR WEST THE TIGHTENED PRESSURE
GRADIENT WILL EXTEND. GALES WILL DEVELOP ACROSS THE LAKE LATE
MONDAY AFTERNOON...AND HAVE ISSUED A GALE WATCH FOR THE OPEN WATERS.
GALES ARE ALSO LIKELY ALONG THE NEARSHORE ZONES...DEVELOPING FIRST
SOUTH AND EAST OF NORTHERLY ISLAND...THEN SPREADING INTO THE
NORTHERN INDIANA NEARSHORE WATERS.
WINDS WILL PROBABLY INCREASE TO STORM FORCE GUSTS TO 50 KT FOR A
TIME ON TUESDAY ACROSS THE LAKE AND NEARSHORE WATERS SOUTH AND EAST
OF NORTHERLY ISLAND. WHILE CONFIDENCE IS HIGH THAT THERE WILL BE AN
EXTENDED PERIOD OF GALES...ONLY HAVE MODERATE CONFIDENCE IN STORM
FORCE GUSTS. MULTIPLE GUIDANCE MEMBERS INDICATE THE PRESSURE
GRADIENT WILL TIGHTEN TUESDAY AND SUSTAINED GUSTS UP TO 50 KT ARE
POSSIBLE...BUT WANT TO SEE IF NEXT SET OF MODEL RUNS REMAIN
CONSISTENT. THEREFORE WILL HOLD OFF ON ISSUING A STORM FORCE
WATCH NOW.
IT CURRENTLY LOOKS LIKE WINDS WILL DIMINISH TO BELOW GALES LATE
WEDNESDAY EVENING/EARLY WEDNESDAY NIGHT. WINDS WILL SLOWLY BECOME
MORE NORTHWEST AND DIMINISH AS THE LOW OVER THE EAST COAST WEAKENS
AND LIFTS TO THE NORTHEAST. RELIEF FROM THE PERSISTENT NORTH WINDS
LOOKS LIKE IT MAY ARRIVE NEXT SATURDAY.
JEE
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE NORTHERLY IS TO MICHIGAN CITY IN UNTIL 1 PM
MONDAY.
GALE WATCH...LMZ742-LMZ743-LMZ744-LMZ745...1 PM MONDAY TO 4 PM
WEDNESDAY.
SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO NORTHERLY IS UNTIL 10 PM MONDAY.
GALE WATCH...LMZ740-LMZ741...10 PM MONDAY TO 10 PM TUESDAY.
GALE WATCH...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...1 PM MONDAY TO 9 PM
WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
426 PM CDT SAT OCT 27 2012
.DISCUSSION...
330 PM CDT
MAIN FORECAST CONCERNS/CHALLENGES ARE WITH PERSISTENT LAKE EFFECT
CLOUD COVER AND LIGHT SHOWERS WITH COOL DRY CONDITIONS EXPECTED
FOR THE REMAINDER OF THE CWA...WITH EVENTUALLY OUR WEATHER TO BE
DICTATED BY LARGE SCALE PATTERN OWING TO SANDY.
WITH THE LAKE EFFECT CLOUD COVER AND ISOLATED LIGHT SHOWERS
AFFECTING AREAS NEAR THE LAKE IN NORTHWEST INDIANA AND EVENTUALLY
NORTHEAST ILLINOIS TONIGHT...HAVE MADE ONLY MINOR TWEAKS TO THE
POP/WX THROUGH THE REMAINDER OF THE WEEKEND. LATEST SATELLITE
IMAGERY STILL DEPICTING AXIS OF CONVERGENCE ALONG THE EASTERN SIDE
OF THE LAKE AS WELL AS WITH BOTH SURFACE OBS AND RAP ANALYSIS
PAINTING A SIMILAR PICTURE. ALTHOUGH...THIS AXIS OF CONVERGENCE
HAS WEAKENED SOMEWHAT EARLY THIS AFTERNOON WITH THE LOSS OF
SYNOPTIC AND LAND BREEZE INTERACTION...WITH DIURNAL TRENDS AIDING
FOR MORE SYNOPTIC NORTH TO NORTHWEST FLOW ALONG THE EASTERN
PORTIONS OF THE LAKE. NONETHELESS...WITH SUFFICIENT DELTA TS AND
WEAK CONVERGENCE...CLOUD COVER CONTINUES TO DEVELOP AND SPILL
INLAND THIS AFTERNOON. HAD MAINTAINED ISOLATED LIGHT SHOWERS FOR
AREAS ACROSS THE SOUTHEAST PORTION OF THE LAKE AND PORTER COUNTY
WHERE BETTER CONVERGENCE RESIDED...BUT HAVE NOT SEEN MUCH
DEVELOPMENT IF ANY AT ALL THIS AFTERNOON. ALTHOUGH...COULD NOT
RULE OUT SOME SPRINKLES OR LIGHT SHOWERS TO DEVELOP UNDER THIS
BEST AXIS OF CONVERGENCE THROUGH THE REMAINDER OF THE AFTERNOON.
CURRENT SHORT WAVE TROUGH OVER THE ROCKIES/PLAINS WILL QUICKLY
WORK ITS WAY EAST/SOUTHEAST...AS THE LARGE UPPER LEVEL TROUGH DIGS
SOUTH ACROSS THE REGION TONIGHT. AS THIS OCCURS...LOW LEVEL FLOW
WILL RESPOND AND SHIFT MORE NORTHERLY/NORTHEASTERLY. THIS SHIFT IN
FLOW WILL BRING THIS CONVERGENT AXIS WEST ORIENTING ITSELF SUCH
THAT I EXPECT CURRENT CLOUD COVER TO BEGIN SPILLING ONTO NORTHEAST
ILLINOIS. THE PRESENCE OF SIMILAR DELTA TS WITH ONCE
AGAIN...INCREASING LOW LEVEL CONVERGENCE TONIGHT...EXPECT LAKE
EFFECT CLOUD COVER TO PERSIST WITH SLIGHTLY BETTER CHANCES FOR
SOME ISOLATED LIGHT SHOWERS. A LONGER FETCH EXTENDING FROM THE FAR
NORTHERN PORTIONS OF THE LAKE SHOULD AID IN A BETTER ENVIRONMENT
FOR THIS LIGHT PRECIP TO DEVELOP. HIRES DATA DOES SUPPORT THIS
SCENARIO WITH GUIDANCE SHOWING A NARROW AXIS DEVELOPING FROM MID
LAKE AND THEN EXTENDING SOUTHWEST INTO FAR NORTHEAST ILLINOIS AND
FAR NORTHWEST INDIANA. WITH PREVIOUSLY MENTIONED CONDITIONS IN
PLACE...CANNOT REALLY ARGUE THIS POSSIBILITY. ALTHOUGH...I WONDER
HOW MUCH MOISTURE WILL BE AVAILABLE FOR THIS WEAK FORCING TO WORK
WITH. THIS WILL OF COURSE PLAY A BIG PART WITH OVERALL
DEVELOPMENT...BUT MORE IMPORTANTLY COVERAGE. HAVE TRIED TO ADD
SOME ADDED DETAIL TO THE POP/WX GRID TRYING TO SHOW A MORE NARROW
AXIS OF DEVELOPMENT....KEEPING ISOLATED LIGHT SHOWERS TONIGHT AS
WELL AS FOR MOST OF SUNDAY. ALTHOUGH THIS LIGHT PRECIP WILL BE
SOMEWHAT IN QUESTION...CLOUD COVER WILL NOT AND SHOULD SPAN MOST
OF NORTHEAST ILLINOIS AND NORTHWEST INDIANA LATE TONIGHT INTO
SUNDAY. EXPECT BOUNDARY LAYER FLOW THEN TO SHIFT MORE NORTHERLY
SUNDAY NIGHT INTO MONDAY WITH THIS CLOUD COVER AND ISOLATED
SHOWERS TO SHIFT BACK PRIMARILY INTO NORTHWEST INDIANA. MOISTURE
WILL THEN BE LACKING GOING INTO MONDAY...WITH PRECIP REALLY NOT
BECOMING LIKELY.
DRY CONDITIONS WILL TAKE PLACE FOR THE ENTIRE CWA MONDAY NIGHT
AND THROUGH MOST OF TUESDAY...AS SIGNIFICANT LARGE SCALE
INTERACTION WILL TAKE PLACE ACROSS THE EAST COAST. THIS CURRENT
LARGE SCALE TROUGH OVERHEAD WILL EVENTUALLY INTERACT WITH SANDY
OVER THE EAST COAST DURING THE START OF NEXT WEEK. WHAT THIS WILL
MEAN FOR AREAS IN OUR LOCATION...IS A LARGE STRONG UPPER LEVEL
SYSTEM THAT WILL SPAN MUCH OF THE EASTERN HALF OF THE US. MOISTURE
WRAPPING AROUND THIS SYSTEM WILL THEN WORK ITS WAY NEAR THE CWA
BUT PRIMARILY OVER THE EASTERN PORTION OF LAKE MICHIGAN THROUGH
MID WEEK. ALTHOUGH THERE IS STILL SOME UNCERTAINTY AS TO THE
OVERALL EVOLUTION WITH THIS LARGE SYSTEM AS WELL AS
MOISTURE/PRECIP REACHING THE CWA...IT DOES APPEAR AS THE BEST AXIS
OF PRECIP SHOULD STAY EAST. WHAT IS NOT IN QUESTION MONDAY THROUGH
WEDNESDAY IS THE STRONG NORTHERLY FLOW THAT WILL TAKE PLACE OVER
THE CWA AND MORE IMPORTANTLY OVER THE LAKE. THIS STRONG FLOW WILL
BRING LARGE WAVES CRASHING SOUTH OVER THE SOUTHERN END OF THE LAKE
AND ONTO AREAS NEAR THE LAKE...WITH HIGH WAVES ON BOTH THE
ILLINOIS AND INDIANA NEARSHORE WATERS EXPECTED BUT WITH THE
HIGHEST WAVES EXPECTED OVER INDIANA. WILL CONTINUE TO WATCH THIS
SITUATION CLOSELY AS HIGH WINDS AND EVEN SOME LAKE SHORE FLOODING
COULD EVENTUALLY BE ISSUES FOR AREAS IMMEDIATELY NEAR THE LAKE.
RODRIGUEZ
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* NE WINDS WITH OCCASIONAL GUSTS 15 TO 18 KT THE REST OF THIS
AFTERNOON.
* POSSIBLE NEARBY OR EVEN TEMPORARY BKN030-040 CIGS AT MDW THIS
AFTERNOON AND EARLY EVE.
* LAKE INDUCED MVFR CIGS DEVELOPING LATER TONIGHT AND PERSISTING
INTO SUNDAY MORNING.
//DISCUSSION...UPDATED 18Z...
HIGH PRESSURE REMAINS AND WILL REMAIN PARKED FROM KANSAS CITY TO
SOUTHWEST WI. THIS WILL RESULT IN CONTINUED NORTHERLY FLOW ACROSS
THE AREA. SIMILAR WIND CONDITIONS AS OBSERVED YESTERDAY ARE
PRESENT THIS AFTERNOON...SO DO EXPECT AND ALREADY HAVE SEEN TO
SOME DEGREE LAKE INFLUENCE MOVING INTO THE CHICAGOLAND TAF SITES.
THIS SHOULD HELP SHIFT THE WINDS AT ORD AND MDW TO THE NE. THE
COOLER FLOW OVER THE LAKE HAS RESULTED IN BKN 030-040 CIGS JUST
EAST OF MDW INTO NW IN. THE CONVERGENT AXIS FAVORING THE CLOUDS IN
THESE LOCATIONS IS LIKELY TO GENERALLY HOLD IN PLACE THROUGH THE
REST OF THIS AFTERNOON BEFORE SHIFTING TO THE WEST ACROSS CHICAGO
LATE TONIGHT INTO SUNDAY. A LONGER FETCH OVER THE LAKE SHOULD
RESULT IN BKN TO OVC CLOUDS FOR THE CHICAGO AIRPORTS SUNDAY
MORNING...AND LIKELY TO BE IN THE MVFR CATEGORY FOR THOSE
AIRFIELDS CLOSER TO THE LAKE SHORE. WITH THE SYNOPTIC FLOW
BECOMING MORE NE...GUSTS SHOULD CONTINUE ON SUNDAY THE FLOW OFF
THE FRICTIONLESS LAKE.
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE IN WINDS REMAINING NNE TO NE THROUGH AT LEAST
23Z ONCE THEY SHIFT...MEDIUM CONFIDENCE ON WIND TRENDS AND
SPEEDS AFTER 23Z.
* HIGH CONFIDENCE IN 2500-4000 FT CIGS LATE TONIGHT AND SUNDAY
MORNING. THESE MAY END UP BEING LOWER...BUT HIGH CONFIDENCE THEY
WILL REMAIN ABOVE 1500 FT.
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT AND MONDAY...GENERALLY VFR. SMALL THREAT OF LOCALIZED
LAKE EFFECT MVFR CIGS AND SLIGHT CHANCE OF SHRA.
TUESDAY THROUGH THURSDAY...GENERALLY VFR. LOW PROBABILITY OF
LOCALIZED SHOWERS TUES-WED. BREEZY FROM THE NNW.
FRIDAY...VFR.
MTF
&&
.MARINE...
423 PM CDT
HIGH PRESSURE HAS MOVED OVER THE NORTHERN MISSISSIPPI RIVER VALLEY
THIS AFTERNOON AND THE AXIS OF THE SURFACE RIDGE WILL REMAIN
CENTERED JUST WEST OF LAKE MICHIGAN THROUGH MID NEXT WEEK. NORTH
WINDS ARE ALSO EXPECTED THROUGH MID NEXT WEEK. AS SUCH...CONTINUED
THE SMALL CRAFT ADVISORY FOR HIGH WAVES. WINDS WILL ALSO PICK UP
TO 20 TO 25 KT TONIGHT.
THE REMNANTS OF HURRICANE SANDY MOVE ASHORE LATE MONDAY INTO MONDAY
NIGHT AND GUIDANCE DIFFERS ON HOW FAR WEST THE TIGHTENED PRESSURE
GRADIENT WILL EXTEND. GALES WILL DEVELOP ACROSS THE LAKE LATE
MONDAY AFTERNOON...AND HAVE ISSUED A GALE WATCH FOR THE OPEN WATERS.
GALES ARE ALSO LIKELY ALONG THE NEARSHORE ZONES...DEVELOPING FIRST
SOUTH AND EAST OF NORTHERLY ISLAND...THEN SPREADING INTO THE
NORTHERN INDIANA NEARSHORE WATERS.
WINDS WILL PROBABLY INCREASE TO STORM FORCE GUSTS TO 50 KT FOR A
TIME ON TUESDAY ACROSS THE LAKE AND NEARSHORE WATERS SOUTH AND EAST
OF NORTHERLY ISLAND. WHILE CONFIDENCE IS HIGH THAT THERE WILL BE AN
EXTENDED PERIOD OF GALES...ONLY HAVE MODERATE CONFIDENCE IN STORM
FORCE GUSTS. MULTIPLE GUIDANCE MEMBERS INDICATE THE PRESSURE
GRADIENT WILL TIGHTEN TUESDAY AND SUSTAINED GUSTS UP TO 50 KT ARE
POSSIBLE...BUT WANT TO SEE IF NEXT SET OF MODEL RUNS REMAIN
CONSISTENT. THEREFORE WILL HOLD OFF ON ISSUING A STORM FORCE
WATCH NOW.
IT CURRENTLY LOOKS LIKE WINDS WILL DIMINISH TO BELOW GALES LATE
WEDNESDAY EVENING/EARLY WEDNESDAY NIGHT. WINDS WILL SLOWLY BECOME
MORE NORTHWEST AND DIMINISH AS THE LOW OVER THE EAST COAST WEAKENS
AND LIFTS TO THE NORTHEAST. RELIEF FROM THE PERSISTENT NORTH WINDS
LOOKS LIKE IT MAY ARRIVE NEXT SATURDAY.
JEE
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE NORTHERLY IS TO MICHIGAN CITY IN UNTIL 1 PM
MONDAY.
GALE WATCH...LMZ742-LMZ743-LMZ744-LMZ745...1 PM MONDAY TO 4 PM
WEDNESDAY.
SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO NORTHERLY IS UNTIL 10 PM MONDAY.
GALE WATCH...LMZ740-LMZ741...10 PM MONDAY TO 10 PM TUESDAY.
GALE WATCH...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...1 PM MONDAY TO 9 PM
WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
336 PM CDT SAT OCT 27 2012
.DISCUSSION...
330 PM CDT
MAIN FORECAST CONCERNS/CHALLENGES ARE WITH PERSISTENT LAKE EFFECT
CLOUD COVER AND LIGHT SHOWERS WITH COOL DRY CONDITIONS EXPECTED
FOR THE REMAINDER OF THE CWA...WITH EVENTUALLY OUR WEATHER TO BE
DICTATED BY LARGE SCALE PATTERN OWING TO SANDY.
WITH THE LAKE EFFECT CLOUD COVER AND ISOLATED LIGHT SHOWERS
AFFECTING AREAS NEAR THE LAKE IN NORTHWEST INDIANA AND EVENTUALLY
NORTHEAST ILLINOIS TONIGHT...HAVE MADE ONLY MINOR TWEAKS TO THE
POP/WX THROUGH THE REMAINDER OF THE WEEKEND. LATEST SATELLITE
IMAGERY STILL DEPICTING AXIS OF CONVERGENCE ALONG THE EASTERN SIDE
OF THE LAKE AS WELL AS WITH BOTH SURFACE OBS AND RAP ANALYSIS
PAINTING A SIMILAR PICTURE. ALTHOUGH...THIS AXIS OF CONVERGENCE
HAS WEAKENED SOMEWHAT EARLY THIS AFTERNOON WITH THE LOSS OF
SYNOPTIC AND LAND BREEZE INTERACTION...WITH DIURNAL TRENDS AIDING
FOR MORE SYNOPTIC NORTH TO NORTHWEST FLOW ALONG THE EASTERN
PORTIONS OF THE LAKE. NONETHELESS...WITH SUFFICIENT DELTA TS AND
WEAK CONVERGENCE...CLOUD COVER CONTINUES TO DEVELOP AND SPILL
INLAND THIS AFTERNOON. HAD MAINTAINED ISOLATED LIGHT SHOWERS FOR
AREAS ACROSS THE SOUTHEAST PORTION OF THE LAKE AND PORTER COUNTY
WHERE BETTER CONVERGENCE RESIDED...BUT HAVE NOT SEEN MUCH
DEVELOPMENT IF ANY AT ALL THIS AFTERNOON. ALTHOUGH...COULD NOT
RULE OUT SOME SPRINKLES OR LIGHT SHOWERS TO DEVELOP UNDER THIS
BEST AXIS OF CONVERGENCE THROUGH THE REMAINDER OF THE AFTERNOON.
CURRENT SHORT WAVE TROUGH OVER THE ROCKIES/PLAINS WILL QUICKLY
WORK ITS WAY EAST/SOUTHEAST...AS THE LARGE UPPER LEVEL TROUGH DIGS
SOUTH ACROSS THE REGION TONIGHT. AS THIS OCCURS...LOW LEVEL FLOW
WILL RESPOND AND SHIFT MORE NORTHERLY/NORTHEASTERLY. THIS SHIFT IN
FLOW WILL BRING THIS CONVERGENT AXIS WEST ORIENTING ITSELF SUCH
THAT I EXPECT CURRENT CLOUD COVER TO BEGIN SPILLING ONTO NORTHEAST
ILLINOIS. THE PRESENCE OF SIMILAR DELTA TS WITH ONCE
AGAIN...INCREASING LOW LEVEL CONVERGENCE TONIGHT...EXPECT LAKE
EFFECT CLOUD COVER TO PERSIST WITH SLIGHTLY BETTER CHANCES FOR
SOME ISOLATED LIGHT SHOWERS. A LONGER FETCH EXTENDING FROM THE FAR
NORTHERN PORTIONS OF THE LAKE SHOULD AID IN A BETTER ENVIRONMENT
FOR THIS LIGHT PRECIP TO DEVELOP. HIRES DATA DOES SUPPORT THIS
SCENARIO WITH GUIDANCE SHOWING A NARROW AXIS DEVELOPING FROM MID
LAKE AND THEN EXTENDING SOUTHWEST INTO FAR NORTHEAST ILLINOIS AND
FAR NORTHWEST INDIANA. WITH PREVIOUSLY MENTIONED CONDITIONS IN
PLACE...CANNOT REALLY ARGUE THIS POSSIBILITY. ALTHOUGH...I WONDER
HOW MUCH MOISTURE WILL BE AVAILABLE FOR THIS WEAK FORCING TO WORK
WITH. THIS WILL OF COURSE PLAY A BIG PART WITH OVERALL
DEVELOPMENT...BUT MORE IMPORTANTLY COVERAGE. HAVE TRIED TO ADD
SOME ADDED DETAIL TO THE POP/WX GRID TRYING TO SHOW A MORE NARROW
AXIS OF DEVELOPMENT....KEEPING ISOLATED LIGHT SHOWERS TONIGHT AS
WELL AS FOR MOST OF SUNDAY. ALTHOUGH THIS LIGHT PRECIP WILL BE
SOMEWHAT IN QUESTION...CLOUD COVER WILL NOT AND SHOULD SPAN MOST
OF NORTHEAST ILLINOIS AND NORTHWEST INDIANA LATE TONIGHT INTO
SUNDAY. EXPECT BOUNDARY LAYER FLOW THEN TO SHIFT MORE NORTHERLY
SUNDAY NIGHT INTO MONDAY WITH THIS CLOUD COVER AND ISOLATED
SHOWERS TO SHIFT BACK PRIMARILY INTO NORTHWEST INDIANA. MOISTURE
WILL THEN BE LACKING GOING INTO MONDAY...WITH PRECIP REALLY NOT
BECOMING LIKELY.
DRY CONDITIONS WILL TAKE PLACE FOR THE ENTIRE CWA MONDAY NIGHT
AND THROUGH MOST OF TUESDAY...AS SIGNIFICANT LARGE SCALE
INTERACTION WILL TAKE PLACE ACROSS THE EAST COAST. THIS CURRENT
LARGE SCALE TROUGH OVERHEAD WILL EVENTUALLY INTERACT WITH SANDY
OVER THE EAST COAST DURING THE START OF NEXT WEEK. WHAT THIS WILL
MEAN FOR AREAS IN OUR LOCATION...IS A LARGE STRONG UPPER LEVEL
SYSTEM THAT WILL SPAN MUCH OF THE EASTERN HALF OF THE US. MOISTURE
WRAPPING AROUND THIS SYSTEM WILL THEN WORK ITS WAY NEAR THE CWA
BUT PRIMARILY OVER THE EASTERN PORTION OF LAKE MICHIGAN THROUGH
MID WEEK. ALTHOUGH THERE IS STILL SOME UNCERTAINTY AS TO THE
OVERALL EVOLUTION WITH THIS LARGE SYSTEM AS WELL AS
MOISTURE/PRECIP REACHING THE CWA...IT DOES APPEAR AS THE BEST AXIS
OF PRECIP SHOULD STAY EAST. WHAT IS NOT IN QUESTION MONDAY THROUGH
WEDNESDAY IS THE STRONG NORTHERLY FLOW THAT WILL TAKE PLACE OVER
THE CWA AND MORE IMPORTANTLY OVER THE LAKE. THIS STRONG FLOW WILL
BRING LARGE WAVES CRASHING SOUTH OVER THE SOUTHERN END OF THE LAKE
AND ONTO AREAS NEAR THE LAKE...WITH HIGH WAVES ON BOTH THE
ILLINOIS AND INDIANA NEARSHORE WATERS EXPECTED BUT WITH THE
HIGHEST WAVES EXPECTED OVER INDIANA. WILL CONTINUE TO WATCH THIS
SITUATION CLOSELY AS HIGH WINDS AND EVEN SOME LAKE SHORE FLOODING
COULD EVENTUALLY BE ISSUES FOR AREAS IMMEDIATELY NEAR THE LAKE.
RODRIGUEZ
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* NE WINDS WITH OCCASIONAL GUSTS 15 TO 18 KT THE REST OF THIS
AFTERNOON.
* POSSIBLE NEARBY OR EVEN TEMPORARY BKN030-040 CIGS AT MDW THIS
AFTERNOON AND EARLY EVE.
* LAKE INDUCED MVFR CIGS DEVELOPING LATER TONIGHT AND PERSISTING
INTO SUNDAY MORNING.
//DISCUSSION...UPDATED 18Z...
HIGH PRESSURE REMAINS AND WILL REMAIN PARKED FROM KANSAS CITY TO
SOUTHWEST WI. THIS WILL RESULT IN CONTINUED NORTHERLY FLOW ACROSS
THE AREA. SIMILAR WIND CONDITIONS AS OBSERVED YESTERDAY ARE
PRESENT THIS AFTERNOON...SO DO EXPECT AND ALREADY HAVE SEEN TO
SOME DEGREE LAKE INFLUENCE MOVING INTO THE CHICAGOLAND TAF SITES.
THIS SHOULD HELP SHIFT THE WINDS AT ORD AND MDW TO THE NE. THE
COOLER FLOW OVER THE LAKE HAS RESULTED IN BKN 030-040 CIGS JUST
EAST OF MDW INTO NW IN. THE CONVERGENT AXIS FAVORING THE CLOUDS IN
THESE LOCATIONS IS LIKELY TO GENERALLY HOLD IN PLACE THROUGH THE
REST OF THIS AFTERNOON BEFORE SHIFTING TO THE WEST ACROSS CHICAGO
LATE TONIGHT INTO SUNDAY. A LONGER FETCH OVER THE LAKE SHOULD
RESULT IN BKN TO OVC CLOUDS FOR THE CHICAGO AIRPORTS SUNDAY
MORNING...AND LIKELY TO BE IN THE MVFR CATEGORY FOR THOSE
AIRFIELDS CLOSER TO THE LAKE SHORE. WITH THE SYNOPTIC FLOW
BECOMING MORE NE...GUSTS SHOULD CONTINUE ON SUNDAY THE FLOW OFF
THE FRICTIONLESS LAKE.
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE IN WINDS REMAINING NNE TO NE THROUGH AT LEAST
23Z ONCE THEY SHIFT...MEDIUM CONFIDENCE ON WIND TRENDS AND
SPEEDS AFTER 23Z.
* HIGH CONFIDENCE IN 2500-4000 FT CIGS LATE TONIGHT AND SUNDAY
MORNING. THESE MAY END UP BEING LOWER...BUT HIGH CONFIDENCE THEY
WILL REMAIN ABOVE 1500 FT.
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT AND MONDAY...GENERALLY VFR. SMALL THREAT OF LOCALIZED
LAKE EFFECT MVFR CIGS AND SLIGHT CHANCE OF SHRA.
TUESDAY THROUGH THURSDAY...GENERALLY VFR. LOW PROBABILITY OF
LOCALIZED SHOWERS TUES-WED. BREEZY FROM THE NNW.
FRIDAY...VFR.
MTF
&&
.MARINE...
310 AM CDT
HIGH PRESSURE REMAINS IN PLACE ACROSS THE CENTRAL PLAINS AND WILL
DRIFT NORTHWARD THROUGH TONIGHT. HURRICANE SANDY IS OFF THE EAST
COAST OF FLORIDA AND WILL WORK WITH THE HIGH TO THE WEST TO DRIVE
THE WEATHER ACROSS LAKE MICHIGAN THROUGH THE MIDDLE OF NEXT WEEK.
THE WEAKEST PRESSURE GRADIENT IS ACROSS THE NORTHERN PART OF THE
LAKE THIS MORNING BUT THE GRADIENT WILL STRENGTHEN SOMEWHAT AS THE
HIGH LIFTS NORTHWARD ALLOWING WINDS TO INCREASE SLIGHTLY TONIGHT AND
SUNDAY MORNING. WINDS ACROSS THE SOUTHERN PART OF THE LAKE WILL
GENERALLY BE IN THE 15 TO 25 KT RANGE THOUGH THERE MAY BE PERIODS OF
10 TO 20 KT WINDS THROUGH MIDDAY TODAY. THE GRADIENT WILL FURTHER
TIGHTEN SUNDAY NIGHT AND MONDAY AS WHAT REMAINS OF SANDY MOVES
NORTHWARD THEN TURNS WESTWARD INTO THE MID ATLANTIC STATES. BY THAT
TIME THE HIGH WILL HAVE BECOME RE-ESTABLISHED OVER ONTARIO.
NORTHERLY WINDS WILL STEADILY INCREASE TO 30 KT MONDAY WITH A
FURTHER INCREASE TO GALES EXPECTED MONDAY NIGHT. THE TRACK OF THE
REMNANTS OF SANDY WILL BE CRITICAL IN DETERMINING HOW STRONG THE
WINDS BECOME THROUGH WEDNESDAY. A FURTHER WESTWARD PUSH INLAND TO
PENNSYLVANIA OR WESTERN NEW YORK AS SOME GUIDANCE SHOWS WOULD LIKELY
RESULT IN STORM FORCE WINDS ACROSS LAKE MICHIGAN TUESDAY WHERE A
FURTHER EAST TRACK WOULD KEEP WINDS IN THE GALE RANGE. DESPITE THE
UNCERTAINTY HAVE DECENT CONFIDENCE IN RAISING WIND SPEEDS FROM
EARLIER FORECASTS WITH MID RANGE GALES TO 40 KT...WITH PERIODS OF 45
KT POSSIBLE...MAINLY MONDAY NIGHT AND TUESDAY. THAT SAID...STILL
HAVE CONCERNS ABOUT A PERIOD OF STORM FORCE WINDS BUT SEVERAL THINGS
NEED TO COME TOGETHER IN THE ATMOSPHERE THAT WILL DETERMINE THE
TRACK OF SANDY FIRST. REGARDLESS...THE REMNANTS WILL LIKELY HANG
AROUND THE LOWER GREAT LAKES THROUGH THE END OF THE WEEK AND WEAKEN
BUT NORTH TO NORTHWEST WINDS WILL BE SLOW TO DIMINISH BUT LOOK TO
FALL BELOW GALE FORCE LATER WEDNESDAY.
MDB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE NORTHERLY IS TO MICHIGAN CITY IN UNTIL 1 PM
MONDAY.
GALE WATCH...LMZ742-LMZ743-LMZ744-LMZ745...1 PM MONDAY TO 4 PM
WEDNESDAY.
SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO NORTHERLY IS UNTIL 10 PM MONDAY.
GALE WATCH...LMZ740-LMZ741...10 PM MONDAY TO 10 PM TUESDAY.
GALE WATCH...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...1 PM MONDAY TO 9 PM
WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS PITTSBURGH PA
646 PM EDT SAT OCT 27 2012
.SYNOPSIS...
A STALLED COLD FRONT NEAR THE MOUNTAINS...COMBINED WITH NORTHBOUND
HURRICANE SANDY...WILL PROVIDE PERIODS OF CHILLY RAIN DURING THE
UPCOMING DAYS. FOR MONDAY INTO TUESDAY...RAIN MAY BECOME HEAVY
MAKING FLOODING A POSSIBILITY...PLUS IT CAN BE WINDY. THERE MAY
EVEN BE SOME SNOWFALL...WITH POSSIBLE ACCUMULATION ON THE RIDGES.
&&
.NEAR TERM /THROUGH SUNDAY/...
HAVE MADE MINOR CHANGES TO POPS AND TEMPS FOR LATEST UPDATE. THIN
LINE OF SHOWERS HAS NOT MADE AS MUCH EASTWARD PROGRESSION AS
PREVIOUS FORECAST INDICATED...ADDITIONALLY THE SOUTHERN PORTION OF
THE LINE IS DECAYING.
PREVIOUS DISCUSSION...
PER RECENT HRRR AND WRF-NAM MODEL OUTPUT...EXPECT BAND OF LIGHT
RAIN TO MEANDER ACROSS THE UPPER OHIO VALLEY THIS PERIOD. THE RAIN
BAND IS ASSOCIATED WITH STALLED COLD FRONT NEAR THE APPALACHIAN
MOUNTAINS.
FORECASTED TEMPERATURES TO REMAIN MAINLY IN THE 40S PER BLEND OF
RECENT GFS AND NAM MOS.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
PER BLEND OF RECENT MODEL OUTPUT...SREF ECMWF CMC AND GFS...EXPECT
HURRICANE SANDY TO TURN NORTHWESTWARD TOWARD PENNSYLVANIA
MONDAY...WITH THE COLD FRONT STILL STALLED ACROSS THE APPALACHIAN
MOUNTAINS. INTERACTION BETWEEN THE SYSTEMS WILL FURTHER INCREASE
THE JET STREAM ALOFT...AND CAN CAUSE STRONG FRONTOGENETICAL LIFT.
HENCE FORESEE THE POTENTIAL FOR HEAVY RAIN AND STRONG WIND GUSTS
MONDAY INTO TUESDAY. HENCE HAVE ISSUED A FLOOD WATCH AND HIGH WIND
WATCH MONDAY INTO TUESDAY.
SURFACE LAYER COOLING MAY CAUSE COLD ENOUGH TEMPERATURES ACROSS
THE HIGHER WV-MD MOUNTAINS FOR THERE TO BE A PERIOD OF
ACCUMULATING SNOW. ELSEWHERE TEMPERATURES WILL BE MAINLY IN THE
40S.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
THE STRONG LOW RESULTING FROM THE PHASING OF HURRICANE SANDY AND
THE COLD UPPER TROUGH WILL BE SLOW TO EXIT NORTH THIS PERIOD. DUE
TO ALL THE UNCERTAINTY HAVE CONTINUED MENTION OF A CHANCE OF
RAIN SHOWERS INTO FRIDAY WITH SNOW SHOWERS POSSIBLE ACROSS THE
HIGHER WV-MD MOUNTAINS.
FORECASTED CONTINUED COLDER THAN NORMAL TEMPERATURES BASED ON
RECENT GFS AND ECMWF MODEL OUTPUT. ONCE THE COLD LOW CENTER
EXITS...DRYING WILL BEGIN AND TEMPERATURES COULD REBOUND TOWARD
NORMAL VALUES NEXT WEEKEND.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
WITH THE SLOW EASTBOUND COLD FRONT HAVING BARELY REACHED THE WESTERN
SLOPES OF THE APPALACHIAN MOUNTAINS...STRATOCUMULUS
CEILINGS TO BE IN THE IFR RANGE.
VISIBILITIES WITH THE FRONTAL BAND OF LIGHT SHOWERS MAY BECOME
MVFR AT TIMES.
SURFACE WINDS WILL BE MAINLY FROM THE NORTH OR NORTHWEST AT
GENERALLY 6 TO 12 KTS INTO TONIGHT.
EXPECT STRATOCUMULUS CEILINGS TO REMAIN THE IFR RANGE THROUGH
TONIGHT.
.OUTLOOK.../SUNDAY THROUGH WEDNESDAY/...
REMNANT MOISTURE FROM SANDY COMBINED WITH A COLD CANADIAN UPPER
TROUGH WILL BRING FREQUENT IFR RESTRICTIONS DUE TO RAIN THROUGH THIS
PERIOD. WITH THE COLDEST AIR ALOFT TO THE SOUTHWEST OF THE
TERMINALS...VISIBILITY RESTRICTIONS WITH WET SNOW AT KMGW/KZZV MAY START
AS EARLY AS MONDAY NIGHT. THERE IS THE POTENTIAL OF SNOW MIXING IN
WITH RAIN FOR THE PITTSBURGH TERMINALS BY TUESDAY NIGHT. 20KTS WINDS
WITH GUSTS IN EXCESS OF 30KTS WILL ALSO BE POSSIBLE MONDAY AND
TUESDAY.
&&
.HYDROLOGY...
AS MENTIONED ABOVE...RAINFALL TOTALS THROUGH EARLY WEDNESDAY ARE
FORECAST IN THE 2 TO 4.5 INCH RANGE FOR THE MONONGAHELA AND
ALLEGHENY RIVER BASINS. FORECAST MODELS IN THE HANDLING OF THIS
SYSTEMS ACTUAL TRACK. GUIDANCE FROM THE HYDROMETEOROLOGICAL
PREDICTION CENTER HAS GENERALLY THE SAME AREA IN EXCESS OF THREE
INCHES ACROSS THOSE SAME AREAS.
SHOULD EITHER OF THESE TOTAL BE REALIZED ON A WIDESPREAD BASIS...THEN
SMALL STREAM FLOODING WOULD OCCUR BY LATER ON MONDAY AND INTO
TUESDAY...WITH RIVER RISES LATE TUESDAY AND WEDNESDAY...WITH FLOODING
FOLLOWING IF MAXIMUM AMOUNTS ARE REALIZED.
FOR NOW...A MENTION OF SUCH POTENTIAL WILL BE INCLUDED IN THE
HAZARDOUS WEATHER OUTLOOK. ADDITIONAL PRODUCTS WILL FOLLOW DURING
THE NEXT FEW DAYS SHOULD THE SITUATION MATERIALIZE FURTHER.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...FLOOD WATCH FROM MONDAY MORNING THROUGH TUESDAY EVENING FOR
MDZ001.
HIGH WIND WATCH FROM MONDAY AFTERNOON THROUGH TUESDAY EVENING
FOR MDZ001.
OH...FLOOD WATCH FROM MONDAY MORNING THROUGH TUESDAY EVENING FOR
OHZ039>041-048>050-057>059-068-069.
HIGH WIND WATCH FROM MONDAY AFTERNOON THROUGH TUESDAY EVENING
FOR OHZ039>041-048>050-057>059-068-069.
PA...FLOOD WATCH FROM MONDAY MORNING THROUGH TUESDAY EVENING FOR
PAZ007>009-013>016-020>023-029-031-073>076.
HIGH WIND WATCH FROM MONDAY AFTERNOON THROUGH TUESDAY EVENING
FOR PAZ007>009-013>016-020>023-029-031-073>076.
WV...FLOOD WATCH FROM MONDAY MORNING THROUGH TUESDAY EVENING FOR
WVZ001>004-012-021>023-041.
HIGH WIND WATCH FROM MONDAY AFTERNOON THROUGH TUESDAY EVENING
FOR WVZ001>004-012-021>023-041.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
403 PM EDT SAT OCT 27 2012
.SYNOPSIS...
A STALLED COLD FRONT NEAR THE MOUNTAINS...COMBINED WITH NORTHBOUND
HURRICANE SANDY...WILL PROVIDE PERIODS OF CHILLY RAIN DURING THE
UPCOMING DAYS. FOR MONDAY INTO TUESDAY...RAIN MAY BECOME HEAVY
MAKING FLOODING A POSSIBILITY...PLUS IT CAN BE WINDY. THERE MAY
EVEN BE SOME SNOWFALL...WITH POSSIBLE ACCUMULATION ON THE RIDGES.
&&
.NEAR TERM /THROUGH SUNDAY/...
PER RECENT HRRR AND WRF-NAM MODEL OUTPUT...EXPECT BAND OF LIGHT
RAIN TO MEANDER ACROSS THE UPPER OHIO VALLEY THIS PERIOD. THE RAIN
BAND IS ASSOCIATED WITH STALLED COLD FRONT NEAR THE APPALACHIAN
MOUNTAINS.
FORECASTED TEMPERATURES TO REMAIN MAINLY IN THE 40S PER BLEND OF
RECENT GFS AND NAM MOS.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
PER BLEND OF RECENT MODEL OUTPUT...SREF ECMWF CMC AND GFS...EXPECT
HURRICANE SANDY TO TURN NORTHWESTWARD TOWARD PENNSYLVANIA
MONDAY...WITH THE COLD FRONT STILL STALLED ACROSS THE APPALACHIAN
MOUNTAINS. INTERACTION BETWEEN THE SYSTEMS WILL FURTHER INCREASE
THE JET STREAM ALOFT...AND CAN CAUSE STRONG FRONTOGENETICAL LIFT.
HENCE FORESEE THE POTENTIAL FOR HEAVY RAIN AND STRONG WIND GUSTS
MONDAY INTO TUESDAY. HENCE HAVE ISSUED A FLOOD WATCH AND HIGH WIND
WATCH MONDAY INTO TUESDAY.
SURFACE LAYER COOLING MAY CAUSE COLD ENOUGH TEMPERATURES ACROSS
THE HIGHER WV-MD MOUNTAINS FOR THERE TO BE A PERIOD OF
ACCUMULATING SNOW. ELSEWHERE TEMPERATURES WILL BE MAINLY IN THE
40S.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
THE STRONG LOW RESULTING FROM THE PHASING OF HURRICANE SANDY AND
THE COLD UPPER TROUGH WILL BE SLOW TO EXIT NORTH THIS PERIOD. DUE
TO ALL THE UNCERTAINTY HAVE CONTINUED MENTION OF A CHANCE OF
RAIN SHOWERS INTO FRIDAY WITH SNOW SHOWERS POSSIBLE ACROSS THE
HIGHER WV-MD MOUNTAINS.
FORECASTED CONTINUED COLDER THAN NORMAL TEMPERATURES BASED ON
RECENT GFS AND ECMWF MODEL OUTPUT. ONCE THE COLD LOW CENTER
EXITS...DRYING WILL BEGIN AND TEMPERATURES COULD REBOUND TOWARD
NORMAL VALUES NEXT WEEKEND.
&&
.AVIATION /20Z SATURDAY THROUGH THURSDAY/...
WITH THE SLOW EASTBOUND COLD FRONT HAVING BARELY REACHED THE WESTERN
SLOPES OF THE APPALACHIAN MOUNTAINS...STRATOCUMULUS
CEILINGS TO BE IN THE IFR RANGE.
VISIBILITIES WITH THE FRONTAL BAND OF LIGHT SHOWERS MAY BECOME
MVFR AT TIMES.
SURFACE WINDS WILL BE MAINLY FROM THE NORTH OR NORTHWEST AT
GENERALLY 6 TO 12 KTS INTO TONIGHT.
EXPECT STRATOCUMULUS CEILINGS TO REMAIN THE IFR RANGE THROUGH
TONIGHT.
.OUTLOOK.../SUNDAY THROUGH WEDNESDAY/...
REMNANT MOISTURE FROM SANDY COMBINED WITH A COLD CANADIAN UPPER
TROUGH WILL BRING FREQUENT IFR RESTRICTIONS DUE TO RAIN THROUGH THIS
PERIOD. WITH THE COLDEST AIR ALOFT TO THE SOUTHWEST OF THE
TERMINALS...VISIBILITY RESTRICTIONS WITH WET SNOW AT KMGW/KZZV MAY START
AS EARLY AS MONDAY NIGHT. THERE IS THE POTENTIAL OF SNOW MIXING IN
WITH RAIN FOR THE PITTSBURGH TERMINALS BY TUESDAY NIGHT. 20KTS WINDS
WITH GUSTS IN EXCESS OF 30KTS WILL ALSO BE POSSIBLE MONDAY AND
TUESDAY.
&&
.HYDROLOGY...
AS MENTIONED ABOVE...RAINFALL TOTALS THROUGH EARLY WEDNESDAY ARE
FORECAST IN THE 2 TO 4.5 INCH RANGE FOR THE MONONGAHELA AND
ALLEGHENY RIVER BASINS. FORECAST MODELS IN THE HANDLING OF THIS
SYSTEMS ACTUAL TRACK. GUIDANCE FROM THE HYDROMETEOROLOGICAL
PREDICTION CENTER HAS GENERALLY THE SAME AREA IN EXCESS OF THREE
INCHES ACROSS THOSE SAME AREAS.
SHOULD EITHER OF THESE TOTAL BE REALIZED ON A WIDESPREAD BASIS...THEN
SMALL STREAM FLOODING WOULD OCCUR BY LATER ON MONDAY AND INTO
TUESDAY...WITH RIVER RISES LATE TUESDAY AND WEDNESDAY...WITH FLOODING
FOLLOWING IF MAXIMUM AMOUNTS ARE REALIZED.
FOR NOW...A MENTION OF SUCH POTENTIAL WILL BE INCLUDED IN THE
HAZARDOUS WEATHER OUTLOOK. ADDITIONAL PRODUCTS WILL FOLLOW DURING
THE NEXT FEW DAYS SHOULD THE SITUATION MATERIALIZE FURTHER.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...FLOOD WATCH FROM MONDAY MORNING THROUGH TUESDAY EVENING FOR
MDZ001.
HIGH WIND WATCH FROM MONDAY AFTERNOON THROUGH TUESDAY EVENING
FOR MDZ001.
OH...FLOOD WATCH FROM MONDAY MORNING THROUGH TUESDAY EVENING FOR
OHZ039>041-048>050-057>059-068-069.
HIGH WIND WATCH FROM MONDAY AFTERNOON THROUGH TUESDAY EVENING
FOR OHZ039>041-048>050-057>059-068-069.
PA...FLOOD WATCH FROM MONDAY MORNING THROUGH TUESDAY EVENING FOR
PAZ007>009-013>016-020>023-029-031-073>076.
HIGH WIND WATCH FROM MONDAY AFTERNOON THROUGH TUESDAY EVENING
FOR PAZ007>009-013>016-020>023-029-031-073>076.
WV...FLOOD WATCH FROM MONDAY MORNING THROUGH TUESDAY EVENING FOR
WVZ001>004-012-021>023-041.
HIGH WIND WATCH FROM MONDAY AFTERNOON THROUGH TUESDAY EVENING
FOR WVZ001>004-012-021>023-041.
&&
$$
AREA FORECAST DISCUSSION
NWS BUFFALO NY
108 PM EDT SAT OCT 27 2012
.SYNOPSIS...
A COLD FRONT WILL STALL ACROSS NEW YORK...WITH PERIODS OF RAIN AND
COOL TEMPERATURES ACROSS WESTERN NEW YORK THROUGH THE WEEKEND. THE
REMNANTS OF SANDY WILL APPROACH THE REGION NEXT WEEK...RESULTING IN
AN EXTENDED PERIOD OF HEAVY RAIN AND VERY WINDY CONDITIONS EARLY
NEXT WEEK. THE RAIN MAY RESULT IN MINOR FLOODING...AND STRONG WINDS
MAY PRODUCE WIND DAMAGE.
&&
.NEAR TERM /THROUGH TONIGHT/...
RADAR IMAGERY SHOWING STEADY LIGHT RAIN ACROSS THE FAR WESTERN END
OF THE STATE EARLY THIS AFTERNOON...WITH SCATTERED SHOWERS AS FAR
EAST AS A LINE FROM CENTRAL CATTARAUGUS COUNTY TO ROCHESTER. EXPECT
THE RAIN TO REMAIN IN THE SAME BASIC POSITION THROUGH MID AFTERNOON
WITH THE SURFACE FRONT AND MID LEVEL FORCING ESSENTIALLY STALLED.
LATE TODAY THE EASTERN EDGE OF THE RAIN WILL BEGIN TO MOVE EASTWARD
SLOWLY.
A COLD FRONT WILL REMAIN NEARLY STATIONARY ACROSS CENTRAL NEW
YORK TODAY. THIS KEEP ALL OR MOST OF OUR CWA ON THE COOL SIDE OF
THE BOUNDARY. THE FRONT WILL NOT MOVE MUCH TONIGHT...POSSIBLY
MEANDERING JUST A BIT TO THE EAST...BUT FOR THE MOST PART IT WILL
BE STATIONARY.
DESPITE THE POSITION OF THE FRONT...IT IS A TIGHT TEMPERATURE
GRADIENT ALOFT WHICH SERVES AS THE MAIN FOCUS FOR RAIN. A CONSENSUS
OF THE 00Z NAM/RGEM/SREF/GFS GUIDANCE GRADUALLY SHIFT THIS AXIS TO
THE EAST LATER TODAY...WHICH IS A BIT MORE MOVEMENT THAN THE SURFACE
FRONT. RECENT RUNS OF THE HRRR AND RADAR TRENDS SUGGEST A SLIGHTLY
SLOWER PROGRESSION THAN THIS MODEL CONSENSUS...BUT THE TREND SHOULD
BE FINE.
PROVIDING SECONDARY SUPPORT TO THIS BOUNDARY IS DIVERGENCE
ALOFT IN THE RIGHT REAR QUADRANT OF THE UPPER JET. WITH LITTLE
FLOW PERPENDICULAR TO TEMPERATURE GRADIENT...THE COMBINATION OF
THESE FEATURES WILL ONLY PRODUCE A BAND OF LIGHT TO OCCASIONALLY
MODERATE RAIN. RAIN WILL LARGELY REMAIN WEST OF ROCHESTER THROUGH
THE MORNING HOURS TODAY...GRADUALLY SHIFTING EAST TOWARD WATERTOWN
AND SYRACUSE THIS AFTERNOON AND EVENING. THE BAND WILL STALL...OR
EVEN DRIFT BACK WESTWARD TOWARD DAYBREAK SUNDAY MORNING. DESPITE THE
MODEST RAINFALL RATES...THE PERSISTENCE OF THE BAND WILL PRODUCE
SOME DECENT 24 HOUR RAIN TOTALS. MODEL CONSENSUS SUGGESTS BETWEEN
.50 INCHES AND 1.00 INCHES WEST OF ROCHESTER...QUICKLY TAPERING
DOWN TO A TENTH OF AN INCH OR LESS IN EASTERN PORTIONS OF THE CWA.
ITS IMPORTANT TO NOTE THAT THE RAIN IS ASSOCIATED WITH THE
FRONT...AND NOT TROPICAL SYSTEM SANDY. THERE ALSO VIRTUALLY TO NO
THREAT FOR FLOODING THROUGH EARLY SUNDAY MORNING...AS IT WILL BE A
JUST A SOAKING RAINFALL DUE TO THIS FRONT.
TEMPERATURES WILL BE NOTABLY COOLER TODAY...WITH MOST OF THE REGION
ON THE COLD SIDE OF THE FRONT...ESPECIALLY CONSIDERING WE ARE COMING
OFF OF TWO UNSEASONABLY WARM DAYS. GIVEN THE SHALLOW COOL AIR AT THE
SURFACE...EXPECT MOST TEMPERATURE GUIDANCE IS A BIT TOO WARM IN
WESTERN SECTIONS...WHERE IT WILL BE RAINING MOST OF THE DAY. A BLEND
OF THE BIAS CORRECTED SREF AND RGEM WAS USED FOR MOST OF THE
TEMPERATURES...BOTH OF WHICH WERE ON THE COOL SIDE EAST OF THE FRONT
FOR HIGHS TODAY. TEMPERATURES MAY NOT EVEN TOP 50 DEGREES WEST OF
ROCHESTER...WITH HIGHS WARMING TO THE UPPER 50S TO LOWER 60S EAST.
EXPECT PATCHY FOG TO PERSIST THROUGH THE PERIOD...MAINLY ACROSS
HIGHER TERRAIN.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/...
THE FOCUS THIS TIME PERIOD WILL FOCUS ON SANDY AND ITS IMPACTS
UPON NOT ONLY WESTERN AND NORTH CENTRAL NEW YORK...BUT ALONG THE
ENTIRE EASTERN COASTLINE. FIRST...BEFORE WE GET TO SANDY ON MONDAY
LETS LOOK AT SUNDAY.
AN INVERTED TROUGH WILL BE FOUND NUDGING NORTHWARD THROUGH EASTERN
NEW YORK...WITH A STALLED FRONTAL BOUNDARY JUST TO THE WEST OF THIS
TROUGH. ALOFT AN EASTERLY WIND...OR WARM CONVEYOR BELT WILL
TRANSPORT MOISTURE WESTWARD...WITH PWATS RISING TO +1 TO +2SD ABOVE
NORMAL. THIS FRONTAL BOUNDARY WILL AGAIN FOCUS A PERIOD OF LIGHT
RAIN ACROSS THE CWA...WITH THE RIGHT ENTRANCE REGION OF AN 120 KNOT
250 HPA JET OVER WNY SUPPLYING ADDITIONAL SYNOPTIC LIFT. IT IS UNDER
THIS JET ENTRANCE REGION WHERE THE RAIN MIGHT BECOME MODERATE AT
TIMES. WILL PAINT THE HIGHEST QPF ACROSS WNY FOR SUNDAY-SUNDAY
NIGHT.
SUNDAY NIGHT MOISTURE WILL CONTINUE TO STREAM WESTWARD ACROSS THE
CWA AHEAD OF SANDY. A PERIOD OF LIGHT RAIN WILL AT FIRST FOCUS
ACROSS WNY NEAR THE FRONTAL BOUNDARY...THEN LATER MOISTURE STREAMING
NORTHWARD OF SANDY...INTERACTING WITH THE NEARING UPPER LEVEL TROUGH
MAY BRING SOME RAIN LATE SNEAKING INTO CENTRAL NEW YORK.
AS FOR QPF SUNDAY AND SUNDAY NIGHT A RANGE OF JUST A FEW TENTH OF AN
INCH TOWARDS FAR EASTERN PORTIONS OF THE CWA...AND UPWARDS TO AN
INCH ACROSS FAR WNY IN THE VICINITY OF THE FRONTAL BOUNDARY AND
UPPER LEVEL JET ENTRANCE REGION.
THOUGH WE WILL HAVE AN EASTERLY WIND SEVERAL THOUSAND FEET OFF THE
SFC...A BOUNDARY LAYER NORTHERLY WIND WILL CONTINUE TO RAW FEEL TO
THE DAY SUNDAY. HIGHS SUNDAY WILL REMAIN IN THE 40S WEST OF THE SFC
TROUGH...WHILE ALONG I-81 EASTWARD HIGHS WILL LIKELY AVERAGE 50F.
SUNDAY NIGHT WE WILL DROP BACK INTO THE 30S ACROSS WNY...AND MID 40S
TO THE EAST WHERE WARMER AIR CONTINUES TO PUSH WESTWARD FROM THE
ATLANTIC. STILL CANNOT RULE OUT SOME WET HIGHER ELEVATION SNOWFLAKES
ACROSS SOUTHWESTERN NEW YORK STATE.
DISCUSSION ON SANDY...
FIRST A LOOK AT THE MAJOR FEATURES FOR THIS TIME PERIOD. HURRICANE
SANDY IS CURRENTLY SPINNING ON A NORTH TO NORTHEAST TRACK NORTH OF
THE BAHAMAS AND OFF THE FLORIDA COASTLINE THIS MORNING. ON WATER
VAPOR IMAGERY A SHORT WAVE IS FOUND OVER SOUTHERN BRITISH
COLUMBIA...AND THIS FEATURE WILL CARVE A DEEPER CENTRAL US TROUGH
THAT WILL SLIDE EASTWARD...BECOME NEGATIVELY TILTED AND CAPTURE SANDY. TO
OUR EAST A +2SD RIDGE AT 500 HPA IS LOCATED ACROSS EASTERN ATLANTIC
CANADA AND TOWARDS GREENLAND. THIS RIDGE OVER GREENLAND SUPPORTS THE
NEGATIVE PHASE OF THE NAO...AND A NEGATIVE PHASE OF THE NAO CAN
ELUDE TO A BLOCKING PATTERN. THIS BLOCKING PATTERN IS WHAT WILL
ALLOW THE TROUGH TO OUR WEST TO CAPTURE AND TURN SANDY WESTWARD
ACROSS THE EASTERN COASTLINE.
THE DETERMINISTIC 27/00Z MODEL OF THE ECMWF CONTINUES TO DRIVE SANDY
INTO THE DELMARVA PENINSULA MONDAY...WHILE THE DETERMINISTIC 26/00Z
GFS PUSHES SANDY WESTWARD ALONG THE SOUTHERN SHORELINE OF LONG
ISLAND THROUGH THE COURSE OF TUESDAY. THE GEFS MEMBERS SPREAD FROM
NEAR THE EUROPEAN SOLUTION...WHILE SOME MEMBERS BRING SANDY MUCH
FARTHER NORTHWARD MAKING LANDFALL IN NEW ENGLAND. THAT SAID WE ARE
FAIRLY CERTAIN SANDY WILL MAKE LANDFALL SOMETIME EARLY NEXT WEEK
WITH IMPLICATIONS NOW LEANING TOWARDS A PROLONGED RAIN WITH THE
POTENTIAL FOR RIVER AND URBAN FLOODING AND POSSIBLE HIGH WIND THREAT.
IT IS STILL TO EARLY AND TOO MUCH UNCERTAINTY FOR ANY
HEADLINES...BUT WE WILL CONTINUE TO MENTION THE THREATS IN OUR HWO
PRODUCT AS WELL AS HERE BELOW IN THE AFD.
RAIN AND FLOODING...BOTH THE ECMWF AND GFS LINGER A FRONTAL BOUNDARY
ACROSS WNY...AND MOISTURE SURGING WESTWARD TOWARDS THIS FRONT COULD
LEAD TO A PERIOD OF MODERATE TO HEAVY RAIN BEGINNING AS EARLY AS
MONDAY...WITH THE FOCUS OF HEAVY RAIN ACROSS WNY. AS SANDY MOVES
INLAND WE ARE EXPECTING SEVERAL PERIODS OF RAIN IN THE MONDAY
THROUGH TUESDAY NIGHT TIME FRAME...WITH THE HEAVIEST RAIN LIKELY
MONDAY NIGHT AND THROUGH TUESDAY. WE WILL HIGHLIGHT THIS HEAVY RAIN
POTENTIAL IN THE GRIDS. IT IS STILL A LITTLE EARLY TO FOCUS WHERE
THE HEAVIEST RAIN WILL FALL...AND HOW MUCH BUT SEVERAL INCHES OF
RAIN IS EXPECTED.
A LOOK AT THE GEFS MODEL ENSEMBLE RIVER FORECASTS SHOWS THAT SOME OF
OUR CREEKS AND RIVERS...ESPECIALLY ACROSS WESTERN NEW YORK AND THE
GENESEE VALLEY WILL NEED TO BE WATCHED FOR RIVER HEIGHT RISES. A FEW
MEMBERS OF THIS ENSEMBLE DO BRING SEVERAL OF OUR CREEKS...BOTH QUICK
AND SLOW RISERS INTO MINOR FLOODING IN THE MONDAY THROUGH WEDNESDAY
TIMEFRAME. WITH RAINFALL SINCE SEPTEMBER 1ST AROUND AN INCH OR SO
ABOVE NORMAL...AND COMBINED WITH THE WEEKEND RAIN...OUR CREEKS AND
RIVERS THAT WERE PRETTY LOW OVER THE SUMMER HAVE LARGELY RECOVERED
FROM THEIR LOW FLOW. THIS INCREASE IN RIVER FLOW THIS AUTUMN WILL
ONLY INCREASE THE POSSIBILITIES OF ANY RIVER FLOODING NEXT WEEK...AS
WELL AS SMALL CREEKS.
THERE IS ALSO THE POTENTIAL FOR URBAN AND POOR DRAINAGE FLOODING.
THOUGH WE ARE EXPECTING SEVERAL INCHES OF RAINFALL...THIS WILL OCCUR
OVER A SEVERAL DAY TIME PERIOD POSSIBLY ALLOWING THE GROUND TO
HANDLE SUCH HIGH RAINFALLS.
WIND...THE SECOND BIG CONCERN WITH SANDY FOR OUR AREA WILL BE WIND.
AS SANDY PUSHES INLAND AND NEARS OUR REGION AN INCREASE IN WIND
SPEED...LIKELY A NORTH TO NORTHEAST WIND... IS EXPECTED. AGAIN
MODELS WILL LIKELY FLUCTUATE ON WIND SPEED AND PLACEMENT OF PEAK
GUSTS WITH THE TRACK OF THE SYSTEM AND PINPOINTING SPEEDS AT THIS
TIME IS UNCERTAIN. THE HIGHEST WINDS SPEEDS WILL LIKELY COME MONDAY
NIGHT AND INTO TUESDAY BASED OFF BOTH THE CURRENT MODEL RUNS OF THE
27/00Z ECMWF AND GFS. WITH THIS WIND DIRECTION THE AREA MOST LIKELY
IMPACTED BY THE WINDS WILL BE LAKE ONTARIO AND ITS SOUTHERN
SHORELINES. PAST TROPICAL OR DEEP SURFACE LOW EVENTS HAVE SHOWN EVEN
SUBWARNING WIND SPEEDS CAN FALL TREES AS THE NORTHEAST WIND
DIRECTION IS NOT A COMMON HIGH SPEED DIRECTION FOR OUR REGION.
SNOW...THIS IMPACT IS BECOMING LESS LIKELY AS WARM AIR WRAPPING
ACROSS OUR REGION WILL LEAVE THE BOUNDARY LAYER TOO WARM TO SUPPORT
SNOW. TEMPERATURES WILL COOL SOME AT NIGHT AND THERE IS STILL A CHC
FOR HIGHER ELEVATION SNOW MONDAY NIGHT ACROSS SOUTHWESTERN NEW YORK
STATE.
PLEASE CONTINUE TO MONITOR YOUR NATIONAL WEATHER SERVICE FORECAST
FOR UPDATES THROUGH THE WEEKEND AS WE CONTINUE TO FINE TUNE THE
DETAILS.
&&
.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
THIS TIME PERIOD WILL START WITH THE DECAYING REMNANTS OF SANDY
EARLY IN THE PERIOD...TRANSITIONING TO POSSIBLE SNOW BY THE END OF
THE WEEK.
WEDNESDAY THE REMNANT LOW OF SANDY WILL CONTINUE TO BE QUICKLY
FILLING...THOUGH STILL DEEP. POSITION OF WHERE THE LOW WILL BE IS
STILL UNCERTAIN WITH THE 27/00Z ECMWF LINGERING THE LOW NEAR THE
ATLANTIC COASTLINE OF THE MID ATLANTIC STATES...WHILE THE 27/00Z GFS
BRINGS THE LOW FARTHEST INLAND TO NEAR LAKE ERIE. A CONSENSUS OF
THESE TWO MODELS MATCHES CLOSELY WITH THE NHC TRACK WHICH PLACES THE
LOW OVER CENTRAL PENNSYLVANIA. WILL CONTINUE WITH LIKELY POPS ON
WEDNESDAY FOR SHOWERS AS THE SYSTEM CONTINUES TO FILL AND LOW LEVEL
OMEGA DISPLAYS LITTLE UPWARD MOTION. QPF WEDNESDAY WILL LIKELY RANGE
FROM HALF AN INCH OR LESS.
WEDNESDAY NIGHT THROUGH THURSDAY NIGHT THE UPPER LEVEL FLOW WILL
REMAIN CUT OFF FROM THE MAIN JET STREAM...ALLOWING THE REMNANT LOW
OF SANDY TO SLOWLY SPIRAL NORTHEASTWARD. THIS WILL LEAD TO ADDITIONAL
PROLONGED PERIOD OF SHOWERS.
BY FRIDAY A MID LEVEL TROUGH WILL BE BARRELING TOWARDS THE ROCKIES
FORCING A DOWNSTREAM UPPER LEVEL RIDGE OVER THE PLAINS. THIS RIDGE
WILL NUDGE THE UPPER LEVEL CUTOFF LOW EASTWARD WITH A COOL
NORTHWESTERLY FLOW THEN REACHING THE CWA. TEMPERATURES AT 850 HPA
DROP TO -1 TO -2C WHICH MAY ALLOW FOR SOME LAKE ENHANCED RAIN AND OR
SNOW SHOWERS ON FRIDAY.
TEMPERATURES THIS THREE DAY TIME PERIOD WILL RUN IN THE 40S BY
DAY...AND 40S TO SOUTHERN TIER INLAND VALLEYS 30S BY NIGHT.
&&
.AVIATION /17Z SATURDAY THROUGH WEDNESDAY/...
WIDESPREAD IFR CONDITIONS WILL CONTINUE THIS AFTERNOON THROUGH
SUNDAY FOR ALL OF WESTERN NEW YORK. THE AREA WILL REMAIN ON THE COOL
SIDE OF A STALLED OUT FRONTAL BOUNDARY...WITH THE MID LEVEL SECTION
OF THAT BOUNDARY PROVIDING A FOCUS FOR PERIODS OF RAIN. THE RAIN
WILL REMAIN IN WESTERN NY THROUGH THE AFTERNOON BEFORE MOVING EAST
ACROSS THE AREA THROUGH THE FIRST HALF OF TONIGHT. LATE TONIGHT
THROUGH SUNDAY THE RAIN WILL MOVE BACK TO THE WEST AS THE FRONTAL
ZONE GETS FORCED WEST BY THE INCREASING OUTER INFLUENCE FROM SANDY.
CIGS WILL BE SOLID IFR THROUGH THE PERIOD ACROSS MOST OF THE AREA...
WITH PERIODS OF IFR VSBY AS WELL IN HEAVIER RAIN AND ALSO IN BR/FG.
THE MOST DENSE FOG WILL BE FOUND ACROSS THE HIGHER TERRAIN OF THE
WESTERN SOUTHERN TIER AND FINGER LAKES WHERE STRATUS WILL INTERSECT
THE HIGHER TERRAIN WITH DENSE FOG ON THE HILLS.
THE ONE EXCEPTION TO ALL OF THIS WILL BE THE NORTH COUNTRY...WHERE
KART WILL REMAIN MVFR THIS AFTERNOON AND EVENING. RAIN AND WEAK LOW
LEVEL CONVERGENCE MAY BRING CIGS DOWN TO IFR LATER TONIGHT THROUGH
SUNDAY MORNING BEFORE SOME IMPROVEMENT BACK TO MVFR ON SUNDAY.
OUTLOOK...
MONDAY...PERIODS OF RAIN AND IFR.
MONDAY NIGHT...HEAVY RAIN AND IFR. STRONG WINDS AT THE SURFACE AND
EXTREMELY STRONG WINDS JUST OFF THE DECK.
TUESDAY THROUGH THURSDAY...OCCASIONAL SHOWERS WITH MVFR/IFR.
&&
.MARINE...
A COLD FRONT STALL OVER EASTERN NEW YORK TODAY. A NORTHERLY
FLOW OF NOTICEABLY COLDER AIR BEHIND THE FRONT WILL RESULT IN SCA
CONDITIONS ALONG THE SOUTHERN SHORES OF BOTH LAKES THROUGH SUNDAY.
THERE IS AN INCREASING POTENTIAL FOR STRONGER WINDS EARLY NEXT WEEK
AS SANDY INTERACTS WITH AN UPPER LEVEL TROF ACROSS THE EASTERN LAKES
EARLY NEXT WEEK. WHILE THE EXACT TRACK AND STRENGTH OF THE STORM IS
UNCERTAIN...IT DOES APPEARS THE STRONGEST WINDS ON BOTH LAKES WILL
LIKELY OCCUR LATE MONDAY THROUGH TUESDAY MORNING. MODEL GUIDANCE
SUGGESTS GALE OR STORM FORCE WINDS ARE A POSSIBILITY DURING THIS
PERIOD.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR LEZ041.
SMALL CRAFT ADVISORY UNTIL 6 PM EDT SUNDAY FOR LEZ040.
SMALL CRAFT ADVISORY UNTIL 6 PM EDT SUNDAY FOR
LOZ042>044.
&&
$$
SYNOPSIS...APFFEL/HITCHCOCK
NEAR TERM...APFFEL/HITCHCOCK
SHORT TERM...THOMAS
LONG TERM...THOMAS
AVIATION...HITCHCOCK
MARINE...APFFEL/THOMAS
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
150 PM EDT SAT OCT 27 2012
.SYNOPSIS...
A COLD FRONT WILL STALL OVER WESTERN PENNSYLVANIA THROUGH TONIGHT.
HURRICANE SANDY WILL CONTINUE TO MOVE NORTH-NORTHEAST PARALLEL TO
THE SOUTHEAST COAST THROUGH THE WEEKEND...BEFORE TURNING TO THE
NORTHWEST TOWARD THE DELMARVA PENINSULA AND NEW JERSEY COAST ON
MONDAY. THE VERY LARGE STORM IS EXPECTED TO IMPACT THE REGION
THROUGH MID-WEEK. THE PRIMARY HAZARDS ASSOCIATED WITH THIS
POTENTIALLY HISTORIC AND DEVASTATING STORM INCLUDE SIGNIFICANT
FLOODING AND WIDESPREAD DAMAGING WINDS.
&&
.NEAR TERM /THROUGH TONIGHT/...
BIGGEST CONCERN IN THE NEAR TERM IS HOW FAR EAST THE RAIN
ASSOCIATED WITH THE NEARLY STATIONARY FRONTAL BOUNDARY WILL MOVE
INTO WESTERN PA. RADAR SHOWS SHOWERS MAINLY OVER WARREN
COUNTY...EDGING ONLY SLOWLY TO THE EAST. I LIKE THE HRRR DEPICTION
OF THE RAIN BAND TIGHTENING UP AND REMAINING OVER NWRN
AREAS...KEEPING THE BULK OF THE FCST AREA DRY INTO SUNDAY.
OTHER CONCERN IS FOR SOME HEAVY RAIN POSSIBLY DEVELOPING IN THIS
FRONTAL ZONE AS THE UPPER JET ENTRANCE REGION INTENSIFIES IN
RESPONSE TO OUTFLOW FROM THE LARGE HURRICANE SANDY...WHICH WILL
HELP BUILD THE HEIGHTS OVER THE NERN US AND CANADIAN
MARITIMES...RESULTING IN A TIGHTENING AND ANTICYCLONIC ELONGATING
OF THE IMPRESSIVE JET ENTRANCE. SO FAR HOWEVER...RAINFALL HAS NOT
BEEN TERRIBLY HEAVY.
&&
.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
NO MAJOR CHANGES SEEN FOR SUNDAY. THE SQUEEZE PLAY /BETWEEN THE
APPROACHING AND AMPLIFYING MIDWEST UPPER TROUGH/CFRONT...AND THE
PLUME OF DEEP TROPICAL AND ATLANTIC MOISTURE AHEAD OF TS SANDY/ WILL
LEAD TO A BLOSSOMING AREA OF STEADY LIGHT TO MODERATE RAIN ACROSS
THE REGION...MAINLY LATER SUNDAY INTO SUNDAY NIGHT.
THE NW AND SE SECTIONS OF PENN /INCLUDING THE LWR SUSQ VALLEY/
WILL SEE THE STEADIEST RAIN SUNDAY WITH AN ADDITIONAL 0.25-0.50 BY
00Z MONDAY...WHILE MOST OF THE CENTRAL RIDGE AND VALLEY REGION WILL
SEE RELATIVELY LIGHTER AMOUNTS.
AFTERWARD...THE WAITING GAME NEARS ITS GRAND FINALE /WITH RESPECT TO
SANDY`S HEAVY RAIN AND LANDFALL LOCATION/ AS SHE BEGINS HER
NORTHWEST CURL TOWARD THE MID ATLANTIC SEABOARD FROM THE WARM GULF
STREAM WATERS VERY EARLY MONDAY MORNING. A LARGE SWATH OF
INCREASINGLY HEAVY RAIN WILL SPREAD NNWD WELL AHEAD OF SANDY...AND
INTO THE SOUTHEASTERN PART OF THE CWA LATE SUNDAY NIGHT...BEFORE
EXPANDING INTO THE CENTRAL PA ZONES ON MONDAY.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
LATEST 00Z-06Z MODEL GUIDANCE CONTINUES TO TIGHTEN UP THE RANGE OF
POSSIBLE LANDFALL LOCATIONS...WITH THE MEAN NOW BEING BETWEEN
ATLANTIC CITY NEW JERSEY...AND OCEAN CITY MARYLAND MONDAY EVENING.
THIS PATH IS VERY OMINOUS FOR THE LARGE POPULATION AREA OF
SOUTHEASTERN PA AND THE LOWER SUSQ VALLEY...WITH BANDS SQUALLS
CONTAINING EXCESSIVE RAINFALL AND STRONG DAMAGING WIND GUSTS
IMPACTING THE REGION. TO COMPLICATE MATTERS...THERE WILL ALSO LIKELY
BE A SEVERE WEATHER/TORNADO THREAT NEAR...AND TO THE NORTH OF THE
KLNS AND KMDT AREAS LATER MONDAY NIGHT.
WIND FIELDS SURROUNDING THE LOW CENTER WILL BE VERY IMPRESSIVE
MONDAY INTO TUESDAY AS SANDY TAKES A LIKELY TRACK WWD INTO CENTRAL
OR SOUTHERN PENN. NORTHEAST TO NW WINDS OF 60 PLUS KTS ARE FCST TO
BE ONLY ABOUT 2 KFT AGL...WITH THE 50 KT CONTOUR AT 1 KFT AGL.
THESE WINDS WILL EASILY BE MIXED DOWN TO THE SFC BY THE HEAVY
RAIN-BANDS...BUT LIKELY MOST SEVERELY IMPACT THE HIGHER TERRAIN OF
THE SOUTH AND EAST...BEFORE BECOMING SLIGHTLY DAMPENED TWD THE
CENTRAL MTNS. HEAVIER QUASI-SPIRAL RAIN BANDS WILL EASILY MIX OUT
OCNL GUSTS AROUND 50KTS SHOULD THIS EXPECTED MODEL MEAN TRACK /AND
TPCS/ VERIFY.
WE POSTED A FLOOD WATCH FOR THE SE ZONES A SHORT TIME AGO...AND IT
WILL RUN FROM 06Z MONDAY THROUGH 00Z WED...WITH 4 INCHES OF MORE
LOOKING LIKE A GOOD POTENTIAL. LOCALIZED MUCH HEAVIER AMOUNTS OF
6-10 INCHES ARE ALSO WITHIN THE REALM OF POSSIBILITIES AS THE HYBRID
STORM IN CAPTURED...THEN ABSORBED BY THE AMPLIFYING AND STRONGLY NEG
TILT UPPER TROUGH.
IN ADDITION TO THE PLETHORA OF PROBLEMS RELATED TO WIND...RAIN AND
POTENTIAL SEVERE CONVECTION...THE POTENTIAL FOR SEVERAL INCHES OF
HEAVY WET SNOW STILL REMAINS FOR THE RIDGES OF THE LAUREL HIGHLANDS
BEGINNING LATE MONDAY OR MONDAY NIGHT...AND CONTINUING THROUGH
TUESDAY AS THE 850 MB WET BULB TEMPS COOL TO JUST UNDER 0C FROM THE
SOUTHWEST. MUCH HEAVIER SNOW IS EXPECTED FURTHER SOUTH ACROSS THE
MTNS OF WVA.
SANDY AND THE UPPER TROUGH CAPTURING IT FROM THE WEST...EVOLVE INTO
A LARGE/STACKED LOW ACROSS THE NRN VIRGINIAS OR CENTRAL PENN TUESDAY
BEFORE GRADUALLY FILLING AND DRIFTING NNE DURING THE MIDWEEK.
SCATTERED TO NUMEROUS RAIN SHOWERS...MIXED WITH SOME WET SNOW ACROSS
THE RIDGES WILL FOLLOW FOR THE MID-WEEK/HALLOWEEN PERIOD.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
LOTS OF LOW CLOUDS ACROSS CENTRAL PA THIS AFTN. KBFD /WHICH WAS
SOCKED IN WITH 200FT CIGS AND FOG ALL MORNING/ HAS SEEN THE FOG
SCOUR OUT AND CIGS RISE THIS AFTN...AS WINDS SHIFTED FROM
NORTHEASTERLY TO SOUTHEASTERLY.
A COLD FRONT AND ITS ACCOMPANYING N-S BAND OF LGT TO MOD RA WILL
PERSIST INTO TONIGHT ACROSS WRN PA...AS THE FRONT STRUGGLES TO
MAKE MUCH EASTWARD PROGRESS. EXPECT WINDS TO BACK FROM
SOUTHEASTERLY TO NORTHEASTERLY AT KBFD...WHICH SHOULD RESULT IN A
RETURN OF IFR/LIFR CONDS. THE SAME SHOULD HAPPEN AT KJST AS WELL.
LOW MVFR/IFR CONDS EXPECTED TO DEVELOP THIS EVENING INTO TONIGHT
AT OTHER CENTRAL PA TAF SITES AS WELL...WITH LIGHT RAIN/DRIZZLE
POSSIBLE.
CONDITIONS WILL BEGIN TO DETERIORATE FURTHER LATE SUNDAY INTO
MONDAY...AS SANDY SLOWLY APPROACHES THE REGION.
OUTLOOK...
SUN...MVFR/IFR CONDS PERSISTING...WITH -RA POSSIBLE.
SUN NIGHT-TUE...WIDESPREAD MVFR/IFR. PERIODS OF MOD-HVY RAIN AND
STRONG WINDS/LLWS ASSOC WITH SANDY.
WED-THU...BREEZY. MVFR/IFR WITH -RA/SN SHRA WEST...MVFR CENTRAL
AND EAST.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
FLOOD WATCH FROM LATE SUNDAY NIGHT THROUGH TUESDAY EVENING FOR
PAZ056>059-063>066.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...LA CORTE
SHORT TERM...LA CORTE
LONG TERM...FITZGERALD/LAMBERT
AVIATION...EVANEGO
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1233 PM EDT SAT OCT 27 2012
.SYNOPSIS...
A COLD FRONT WILL STALL OVER WESTERN PENNSYLVANIA THROUGH TONIGHT.
HURRICANE SANDY WILL CONTINUE TO MOVE NORTH-NORTHEAST PARALLEL TO
THE SOUTHEAST COAST THROUGH THE WEEKEND...BEFORE TURNING TO THE
NORTHWEST TOWARD THE DELMARVA PENINSULA AND NEW JERSEY COAST ON
MONDAY. THE VERY LARGE STORM IS EXPECTED TO IMPACT THE REGION
THROUGH MID-WEEK. THE PRIMARY HAZARDS ASSOCIATED WITH THIS
POTENTIALLY HISTORIC AND DEVASTATING STORM INCLUDE SIGNIFICANT
FLOODING AND WIDESPREAD DAMAGING WINDS.
&&
.NEAR TERM /THROUGH TONIGHT/...
BIGGEST CONCERN IN THE NEAR TERM IS HOW FAR EAST THE RAIN
ASSOCIATED WITH THE NEARLY STATIONARY FRONTAL BOUNDARY WILL MOVE
INTO WESTERN PA. RADAR SHOWS SHOWERS MAINLY OVER WARREN
COUNTY...EDGING ONLY SLOWLY TO THE EAST. I LIKE THE HRRR DEPICTION
OF THE RAIN BAND TIGHTENING UP AND REMAINING OVER NWRN
AREAS...KEEPING THE BULK OF THE FCST AREA DRY INTO SUNDAY.
OTHER CONCERN IS FOR SOME HEAVY RAIN POSSIBLY DEVELOPING IN THIS
FRONTAL ZONE AS THE UPPER JET ENTRANCE REGION INTENSIFIES IN
RESPONSE TO OUTFLOW FROM THE LARGE HURRICANE SANDY...WHICH WILL
HELP BUILD THE HEIGHTS OVER THE NERN US AND CANADIAN
MARITIMES...RESULTING IN A TIGHTENING AND ANTICYCLONIC ELONGATING
OF THE IMPRESSIVE JET ENTRANCE. SO FAR HOWEVER...RAINFALL HAS NOT
BEEN TERRIBLY HEAVY.
&&
.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
NO MAJOR CHANGES SEEN FOR SUNDAY. THE SQUEEZE PLAY /BETWEEN THE
APPROACHING AND AMPLIFYING MIDWEST UPPER TROUGH/CFRONT...AND THE
PLUME OF DEEP TROPICAL AND ATLANTIC MOISTURE AHEAD OF TS SANDY/ WILL
LEAD TO A BLOSSOMING AREA OF STEADY LIGHT TO MODERATE RAIN ACROSS
THE REGION...MAINLY LATER SUNDAY INTO SUNDAY NIGHT.
THE NW AND SE SECTIONS OF PENN /INCLUDING THE LWR SUSQ VALLEY/
WILL SEE THE STEADIEST RAIN SUNDAY WITH AN ADDITIONAL 0.25-0.50 BY
00Z MONDAY...WHILE MOST OF THE CENTRAL RIDGE AND VALLEY REGION WILL
SEE RELATIVELY LIGHTER AMOUNTS.
AFTERWARD...THE WAITING GAME NEARS ITS GRAND FINALE /WITH RESPECT TO
SANDY`S HEAVY RAIN AND LANDFALL LOCATION/ AS SHE BEGINS HER
NORTHWEST CURL TOWARD THE MID ATLANTIC SEABOARD FROM THE WARM GULF
STREAM WATERS VERY EARLY MONDAY MORNING. A LARGE SWATH OF
INCREASINGLY HEAVY RAIN WILL SPREAD NNWD WELL AHEAD OF SANDY...AND
INTO THE SOUTHEASTERN PART OF THE CWA LATE SUNDAY NIGHT...BEFORE
EXPANDING INTO THE CENTRAL PA ZONES ON MONDAY.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
LATEST 00Z-06Z MODEL GUIDANCE CONTINUES TO TIGHTEN UP THE RANGE OF
POSSIBLE LANDFALL LOCATIONS...WITH THE MEAN NOW BEING BETWEEN
ATLANTIC CITY NEW JERSEY...AND OCEAN CITY MARYLAND MONDAY EVENING.
THIS PATH IS VERY OMINOUS FOR THE LARGE POPULATION AREA OF
SOUTHEASTERN PA AND THE LOWER SUSQ VALLEY...WITH BANDS SQUALLS
CONTAINING EXCESSIVE RAINFALL AND STRONG DAMAGING WIND GUSTS
IMPACTING THE REGION. TO COMPLICATE MATTERS...THERE WILL ALSO LIKELY
BE A SEVERE WEATHER/TORNADO THREAT NEAR...AND TO THE NORTH OF THE
KLNS AND KMDT AREAS LATER MONDAY NIGHT.
WIND FIELDS SURROUNDING THE LOW CENTER WILL BE VERY IMPRESSIVE
MONDAY INTO TUESDAY AS SANDY TAKES A LIKELY TRACK WWD INTO CENTRAL
OR SOUTHERN PENN. NORTHEAST TO NW WINDS OF 60 PLUS KTS ARE FCST TO
BE ONLY ABOUT 2 KFT AGL...WITH THE 50 KT CONTOUR AT 1 KFT AGL.
THESE WINDS WILL EASILY BE MIXED DOWN TO THE SFC BY THE HEAVY
RAIN-BANDS...BUT LIKELY MOST SEVERELY IMPACT THE HIGHER TERRAIN OF
THE SOUTH AND EAST...BEFORE BECOMING SLIGHTLY DAMPENED TWD THE
CENTRAL MTNS. HEAVIER QUASI-SPIRAL RAIN BANDS WILL EASILY MIX OUT
OCNL GUSTS AROUND 50KTS SHOULD THIS EXPECTED MODEL MEAN TRACK /AND
TPCS/ VERIFY.
WE POSTED A FLOOD WATCH FOR THE SE ZONES A SHORT TIME AGO...AND IT
WILL RUN FROM 06Z MONDAY THROUGH 00Z WED...WITH 4 INCHES OF MORE
LOOKING LIKE A GOOD POTENTIAL. LOCALIZED MUCH HEAVIER AMOUNTS OF
6-10 INCHES ARE ALSO WITHIN THE REALM OF POSSIBILITIES AS THE HYBRID
STORM IN CAPTURED...THEN ABSORBED BY THE AMPLIFYING AND STRONGLY NEG
TILT UPPER TROUGH.
IN ADDITION TO THE PLETHORA OF PROBLEMS RELATED TO WIND...RAIN AND
POTENTIAL SEVERE CONVECTION...THE POTENTIAL FOR SEVERAL INCHES OF
HEAVY WET SNOW STILL REMAINS FOR THE RIDGES OF THE LAUREL HIGHLANDS
BEGINNING LATE MONDAY OR MONDAY NIGHT...AND CONTINUING THROUGH
TUESDAY AS THE 850 MB WET BULB TEMPS COOL TO JUST UNDER 0C FROM THE
SOUTHWEST. MUCH HEAVIER SNOW IS EXPECTED FURTHER SOUTH ACROSS THE
MTNS OF WVA.
SANDY AND THE UPPER TROUGH CAPTURING IT FROM THE WEST...EVOLVE INTO
A LARGE/STACKED LOW ACROSS THE NRN VIRGINIAS OR CENTRAL PENN TUESDAY
BEFORE GRADUALLY FILLING AND DRIFTING NNE DURING THE MIDWEEK.
SCATTERED TO NUMEROUS RAIN SHOWERS...MIXED WITH SOME WET SNOW ACROSS
THE RIDGES WILL FOLLOW FOR THE MID-WEEK/HALLOWEEN PERIOD.
&&
.AVIATION /16Z SATURDAY THROUGH WEDNESDAY/...
A COLD FRONT AND ACCOMPANYING N-S BAND OF LGT TO MOD RA WILL
CONTINUE ACROSS NORTHWESTERN PA THROUGH THIS AFTN/EVE. SUBSIDENCE
BETWEEN THE FRONT AND T.S. SANDY SHOULD KEEP THINGS MAINLY DRY
ACRS CENTRAL AND ERN SXNS. CIGS MAY RISE A BIT DURING THE
AFTN...BUT NOT MUCH.
AS WITH THE PAST FEW NIGHTS...EXPECT CIGS TO LOWER TO LOW MVFR-IFR
CONDS TONIGHT. FRONTAL RAINS WILL CONTINUE ACRS WRN SXNS WITH
POCKETS OF -RADZ ACRS CENTRAL AND ERN SITES.
OUTLOOK...
SUN-TUE...WIDESPREAD MVFR/IFR. PERIODS OF MOD-HVY RAIN AND STRONG
WINDS/LLWS ASSOC WITH SANDY. RAIN MAY CHANGE TO SNOW IN THE SW PA
MTNS ON TUE.
WED...BREEZY. MVFR/IFR WITH RA-SN SHOWERS WEST...MVFR CENTRAL AND
EAST.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
FLOOD WATCH FROM LATE SUNDAY NIGHT THROUGH TUESDAY EVENING FOR
PAZ056>059-063>066.
&&
$$
SYNOPSIS...LA CORTE/STEINBUGL
NEAR TERM...LA CORTE/STEINBUGL
SHORT TERM...FITZGERALD/LAMBERT
LONG TERM...FITZGERALD/LAMBERT
AVIATION...STEINBUGL/EVANEGO
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
601 PM CDT SAT OCT 27 2012
UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND SUNDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW SURFACE HIGH
PRESSURE STRETCHING FROM WESTERN TEXAS TO THE NORTHERN MISSISSIPPI
VALLEY EARLY THIS AFTERNOON. DIURNAL CU TOOK A LITTLE WHILE TO
POP...BUT GOT GOING AROUND NOON TODAY OVER WESTERN AND NORTHERN
WISCONSIN. LOOKING UPSTREAM...PLENTY OF MID AND HIGH CLOUDS OVER
THE NORTHERN PLAINS AS WEAK SHORTWAVE ACTIVITY MOVES AROUND THE MEAN
TROUGH OVER THE CENTRAL PART OF THE CONTINENT. A COUPLE REPORTS OF
SNOW FALLING OUT OF THESE CLOUDS OVER NORTH DAKOTA...BUT NOTHING
FALLING FURTHER SOUTH. WITH A DRY AIRMASS IN PLACE...CLOUDS AND
TEMPS WILL BE THE MAIN FORECAST CONCERNS AS HIGH PRESSURE BUILDS
INTO THE REGION.
TONIGHT...SURFACE RIDGE AXIS MOVES INTO THE STATE FROM THE NORTHERN
PLAINS. BUT SHORTWAVE ENERGY FROM THE CENTRAL PLAINS WILL BE MOVING
INTO THE MISSISSIPPI VALLEY...AND MID/HIGH CLOUDS WILL BE SPREADING
ACROSS THE AREA THIS EVENING FROM SOUTHWEST TO NORTHEAST. THESE
CLOUDS DO NOT LOOK REAL THICK OR SOLID IN APPEARANCE ON SATELLITE
IMAGERY...AND TEMPS WERE STILL ABLE TO FALL INTO THE LOW TO MID 20S
UPSTREAM. LOW LEVEL WINDS WILL SWING AROUND FROM THE NORTHWEST TO
THE NORTHEAST OVER NORTHERN LAKE MICHIGAN THIS EVENING. TRAJECTORY
OF WINDS SUGGESTS MANITOWOC COUNTY MAY GET GRAZED BY LAKE CLOUDS.
WINDS LOOK A LITTLE TOO NORTHERLY OVER GREEN BAY FOR BAY CLOUDS TO
IMPACT THE FOX VALLEY...BUT SHOULD KEEP TEMPS SLIGHTLY WARMER. WILL
GO WITH LOWS RANGING FROM THE UPPER TEENS OVER N-C WISCONSIN...TO THE
LOWER 30S NEAR LAKE MICHIGAN.
SUNDAY...HIGH PRESSURE RIDGE AXIS BECOMES OVERHEAD ON SUNDAY. WINDS
TURN MORE NORTHEASTERLY OVER NORTHEAST WISCONSIN...WHICH WILL ADVECT
LAKE MOISTURE INLAND FROM THE FOX VALLEY ON EASTWARD. IF LAKE/BAY
CLOUDS DO NOT PUSH INLAND IN THE MORNING...DIURNAL HEATING SHOULD
ALLOW FOR A CU FIELD TO DEVELOP BY MIDDAY. MID AND HIGH CLOUDS WILL
STILL BE OVERHEAD DURING THE MORNING...BUT RH PROGS SUGGEST SOME
THINNING/DISSIPATION OF CLOUDS DURING THE AFTERNOON. IN THE
END...WENT WITH PARTLY/MOSTLY CLOUDY IN THE MORNING...AND INCREASING
SUNSHINE IN THE AFTERNOON. HIGHS A DEGREE OR TWO WARMER THAN TODAY.
.LONG TERM...SUNDAY NIGHT THRU NEXT SATURDAY.
CONCERNS THIS PERIOD IN BEGINNING PART OF FORECAST MON NIGHT INTO
WEDNESDAY AS AFFECTS OF HURRICANE SANDY PUSH WEST.
HIGH PRESSURE OVER THE REGION SUNDAY NIGHT INTO MONDAY WILL
CONTINUE THE DRY...COOL PATTERN OVER THE REGION. HAVE TRENDED
TOWARDS COLDER GUIDANCE AT NIGHT...BUT TEMPERED A BIT WITH
POSSIBILITY OF MID/HIGH CLOUDS POSSIBLE WEST WITH WARM ADVECTION
SETTING UP.
WITH REGARDS TO SANDY...WENT WITH A BASIC 50/50 BLEND OF GFS/EC.
12Z GFS STAYING PRETTY CLOSE TO PREVIOUS RUN BRINGING SYSTEM
SLIGHTLY FURTHER WEST AND REMAINING ON THE DEEPER SIDE OF
GUIDANCE. THIS MAY BE ATTRIBUTED IN HOW IT IS HANDLING JET ENERGY
WEST OF THE SYSTEM. 00Z EC JOGGED A BIT EAST WITH THE SYSTEM
COMPARED TO ITS PREVIOUS RUN. EITHER WAY ANY PCPN WOULD STAY OVER
FAR EAST PART OF CWA OR OVER LAKE MI TUE INTO WED. WILL CONTINUE
WITH A RAIN SNOW MIX AS SOUNDINGS INDICATE FURTHER COOLING OF
LOWER LAYERS OF ATMOSPHERE POSSIBLE DUE TO EVAPORATIVE EFFECTS.
SANDY TO SLOWLY EXIT TO THE NORTH...NORTHEAST WITH RIDGE BUILDING
IN WED NIGHT/THU. WARMER...AND MAINLY DRY CONDITIONS
EXPECTED FOR THU INTO NEXT SAT
&&
.AVIATION...NICE NIGHT FOR FLYING WITH LIGHT SURFACE WINDS AND
JUST SOME HIGH CLOUDS MOVING IN FROM THE SOUTH. GOOD DAY SUNDAY AS
WELL WITH LIGHT WINDS AND HIGH CLOUDS.
RDM
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
225 PM CDT SAT OCT 27 2012
.SHORT TERM...TONIGHT AND SUNDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW SURFACE HIGH
PRESSURE STRETCHING FROM WESTERN TEXAS TO THE NORTHERN MISSISSIPPI
VALLEY EARLY THIS AFTERNOON. DIURNAL CU TOOK A LITTLE WHILE TO
POP...BUT GOT GOING AROUND NOON TODAY OVER WESTERN AND NORTHERN
WISCONSIN. LOOKING UPSTREAM...PLENTY OF MID AND HIGH CLOUDS OVER
THE NORTHERN PLAINS AS WEAK SHORTWAVE ACTIVITY MOVES AROUND THE MEAN
TROUGH OVER THE CENTRAL PART OF THE CONTINENT. A COUPLE REPORTS OF
SNOW FALLING OUT OF THESE CLOUDS OVER NORTH DAKOTA...BUT NOTHING
FALLING FURTHER SOUTH. WITH A DRY AIRMASS IN PLACE...CLOUDS AND
TEMPS WILL BE THE MAIN FORECAST CONCERNS AS HIGH PRESSURE BUILDS
INTO THE REGION.
TONIGHT...SURFACE RIDGE AXIS MOVES INTO THE STATE FROM THE NORTHERN
PLAINS. BUT SHORTWAVE ENERGY FROM THE CENTRAL PLAINS WILL BE MOVING
INTO THE MISSISSIPPI VALLEY...AND MID/HIGH CLOUDS WILL BE SPREADING
ACROSS THE AREA THIS EVENING FROM SOUTHWEST TO NORTHEAST. THESE
CLOUDS DO NOT LOOK REAL THICK OR SOLID IN APPEARANCE ON SATELLITE
IMAGERY...AND TEMPS WERE STILL ABLE TO FALL INTO THE LOW TO MID 20S
UPSTREAM. LOW LEVEL WINDS WILL SWING AROUND FROM THE NORTHWEST TO
THE NORTHEAST OVER NORTHERN LAKE MICHIGAN THIS EVENING. TRAJECTORY
OF WINDS SUGGESTS MANITOWOC COUNTY MAY GET GRAZED BY LAKE CLOUDS.
WINDS LOOK A LITTLE TOO NORTHERLY OVER GREEN BAY FOR BAY CLOUDS TO
IMPACT THE FOX VALLEY...BUT SHOULD KEEP TEMPS SLIGHTLY WARMER. WILL
GO WITH LOWS RANGING FROM THE UPPER TEENS OVER N-C WISCONSIN...TO THE
LOWER 30S NEAR LAKE MICHIGAN.
SUNDAY...HIGH PRESSURE RIDGE AXIS BECOMES OVERHEAD ON SUNDAY. WINDS
TURN MORE NORTHEASTERLY OVER NORTHEAST WISCONSIN...WHICH WILL ADVECT
LAKE MOISTURE INLAND FROM THE FOX VALLEY ON EASTWARD. IF LAKE/BAY
CLOUDS DO NOT PUSH INLAND IN THE MORNING...DIURNAL HEATING SHOULD
ALLOW FOR A CU FIELD TO DEVELOP BY MIDDAY. MID AND HIGH CLOUDS WILL
STILL BE OVERHEAD DURING THE MORNING...BUT RH PROGS SUGGEST SOME
THINNING/DISSIPATION OF CLOUDS DURING THE AFTERNOON. IN THE
END...WENT WITH PARTLY/MOSTLY CLOUDY IN THE MORNING...AND INCREASING
SUNSHINE IN THE AFTERNOON. HIGHS A DEGREE OR TWO WARMER THAN TODAY.
.LONG TERM...SUNDAY NIGHT THRU NEXT SATURDAY.
CONCERNS THIS PERIOD IN BEGINNING PART OF FORECAST MON NIGHT INTO
WEDNESDAY AS AFFECTS OF HURRICANE SANDY PUSH WEST.
HIGH PRESSURE OVER THE REGION SUNDAY NIGHT INTO MONDAY WILL
CONTINUE THE DRY...COOL PATTERN OVER THE REGION. HAVE TRENDED
TOWARDS COLDER GUIDANCE AT NIGHT...BUT TEMPERED A BIT WITH
POSSIBILITY OF MID/HIGH CLOUDS POSSIBLE WEST WITH WARM ADVECTION
SETTING UP.
WITH REGARDS TO SANDY...WENT WITH A BASIC 50/50 BLEND OF GFS/EC.
12Z GFS STAYING PRETTY CLOSE TO PREVIOUS RUN BRINGING SYSTEM
SLIGHTLY FURTHER WEST AND REMAINING ON THE DEEPER SIDE OF
GUIDANCE. THIS MAY BE ATTRIBUTED IN HOW IT IS HANDLING JET ENERGY
WEST OF THE SYSTEM. 00Z EC JOGGED A BIT EAST WITH THE SYSTEM
COMPARED TO ITS PREVIOUS RUN. EITHER WAY ANY PCPN WOULD STAY OVER
FAR EAST PART OF CWA OR OVER LAKE MI TUE INTO WED. WILL CONTINUE
WITH A RAIN SNOW MIX AS SOUNDINGS INDICATE FURTHER COOLING OF
LOWER LAYERS OF ATMOSPHERE POSSIBLE DUE TO EVAPORATIVE EFFECTS.
SANDY TO SLOWLY EXIT TO THE NORTH...NORTHEAST WITH RIDGE BUILDING
IN WED NIGHT/THU. WARMER...AND MAINLY DRY CONDITIONS
EXPECTED FOR THU INTO NEXT SAT
&&
.AVIATION...FOR THE 12Z TAF ISSUANCE. CLDS BASES TDA SHOULD BE
HIGH ENOUGH TO STAY IN VFR CATEGORY. SOME MVFR CIGS WL LIKELY
DEVELOP TNGT NEAR LAKE MICHIGAN AND THE BAY OF GREEN BAY.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MPC/TE
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1130 AM CDT SAT OCT 27 2012
.SHORT TERM...TODAY THROUGH MONDAY NIGHT
231 AM CDT SAT OCT 27 2012
MAIN FORECAST CONCERNS ARE ON CLOUDS AND TEMPERATURES THROUGHOUT DUE
TO LACK OF PRECIPITATION FORCING MECHANISMS.
CURRENTLY AS OF 07Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
LOOKS VERY SIMILAR TO 24 HOURS AGO WITH RIDGING OVER THE EASTERN
PACIFIC...TROUGHING OVER THE WESTERN TWO THIRDS OF CANADA INTO THE
SOUTHERN PLAINS...RIDGING OVER NEWFOUNDLAND AND TROPICAL STORM SANDY
SITTING JUST NORTH OF THE NORTHWEST BAHAMAS. MAIN SHORTWAVE OF NOTE
WAS OVER SOUTHERN BRITISH COLUMBIA WITH A 130 KT JET STREAK NEAR
225MB IN EASTERN WASHINGTON STATE. A STREAM OF CIRRUS EXTENDED
DOWNSTREAM FROM THIS SHORTWAVE INTO MONTANA AND THE WESTERN DAKOTAS.
FARTHER EAST INTO THE FORECAST AREA...A BROKEN FIELD OF
STRATOCUMULUS COVERED MUCH OF THE UPPER MISSISSIPPI RIVER VALLEY
REGION. THESE CLOUDS WERE REPRESENTED WELL ON THE 00Z MPX SOUNDING
BY YET ANOTHER MOIST LAYER BETWEEN 750-800MB. AIRMASS REMAINS COOL
OVER THE FORECAST AREA WITH 00Z SOUNDINGS SHOWING 850MB TEMPS AROUND
-7C. HOWEVER...THE CLOUDS AND A LIGHT WESTERLY BREEZE NORTH OF HIGH
PRESSURE IN WESTERN IOWA HAVE HELPED TO LIMIT THE TEMPERATURE FALL
TOO MUCH THUS FAR. TEMPERATURES SO FAR HAVE FALLEN INTO THE UPPER
20S TO MID 30S.
TODAY THROUGH SUNDAY...FOCUS FOR OUR AREA IS ON THAT SHORTWAVE IN
SOUTHERN BRITISH COLUMBIA. MODELS ARE IN GOOD AGREEMENT DROPPING IT
DOWN INTO THE BASE OF THE UPPER TROUGH...REACHING FAR WESTERN
NEBRASKA BY 00Z SUNDAY...THE MEMPHIS TN AREA BY 12Z SUNDAY AND THEN
PUSHING EAST TO THE GREAT SMOKY MOUNTAINS AREA BY 00Z MONDAY. AS
THIS SHORTWAVE DIVES SOUTHEAST...EXPECT THE MASS OF CIRRUS ENTERING
THE DAKOTAS TO SPREAD INTO THE FORECAST AREA THIS AFTERNOON AND
EVENING. THUS...EVEN IF THE CURRENT STRATOCUMULUS CONTINUES TO BREAK
UP OR DISSIPATE...THE CLEARING LOOKS TO BE TEMPORARY. THE CIRRUS
APPEARS TO HOLD ON THROUGH MUCH OF TONIGHT...THEN THERE ARE
SUGGESTIONS OF A DECAYING MID CLOUD DECK ASSOCIATED WITH THE
SHORTWAVE MOVING INTO THE AREA FROM THE WEST ON SUNDAY. PLENTY OF
LOW LEVEL DRY AIR AND LACK OF FORCING WILL KEEP THE FORECAST AREA
DRY. HOWEVER...THE CLOUDS ARE LIKELY TO MAKE AN IMPACT ON
TEMPERATURE FORECASTS. BEING IN UPPER TROUGHING AND THE LOW SUN
ANGLE THIS TIME OF YEAR...THE 850MB TEMPS AND GENERAL AIRMASS ARE
GOING TO HAVE A TOUGH TIME WARMING. IN FACT...THE READINGS CHANGE
VERY LITTLE...CLIMBING FROM -6 TO -8C TODAY TO -4 TO -6C ON SUNDAY.
WITH CLOUDS AROUND...ANTICIPATING HIGHS TO STAY STUCK IN THE LOWER
TO MID 40S. THE CIRRUS DECK AND INCOMING MID CLOUDS SHOULD HELP TO
KEEP TEMPERATURES UP TONIGHT...IN THE UPPER 20S TO LOW 30S.
SUNDAY NIGHT THROUGH MONDAY NIGHT...MUCH OF THE ACTION IS EXPECTED
IN THE MID-ATLANTIC AND NORTHEAST U.S. DURING THIS PERIOD...IN
RESPONSE TO INTERACTION AND PHASING OF SANDY WITH THE CURRENT
BRITISH COLUMBIA SHORTWAVE...RELEASE OF LATENT HEAT AND A COUPLING
OF SUBTROPICAL AND POLAR JETS. THE NET RESULT BY 12Z TUESDAY FROM
ALL MODELS IS A DEEP UPPER TROUGH ENCOMPASSING MUCH OF THE EASTERN
U.S. WITH A DEEP POST-TROPICAL SANDY SITUATED IN OR NEAR
PENNSYLVANIA. MEANWHILE...UPPER RIDGING THAT HAS BEEN OVER THE EAST
PACIFIC MODELS HAVE BUILDING ACROSS THE WESTERN U.S. AND INTO THE
WESTERN PLAINS. THIS SETUP EFFECTIVELY BLOCKS ANY PRECIPITATION FROM
ENTERING THE PICTURE FOR OUR AREA. IN FACT...HIGH PRESSURE SHOULD
DOMINATE AT THE SURFACE THROUGH MUCH OF THE TIME PERIOD.
TEMPERATURES LOOK TO STAY COOL DUE TO 850MB TEMPS STILL ONLY WARMING
SLOWLY TO -1 TO -4C ON MONDAY. CLOUD COVER WISE...THERE ARE HINTS OF
SOME WARM ADVECTION MID CLOUDS COMING INTO WESTERN SECTIONS OF THE
AREA ON MONDAY...BUT THEN THESE GET SHUNTED SOUTHWEST BY SUBSIDENCE
ON THE BACK SIDE OF THE DEEP EASTERN TROUGH.
.LONG TERM...TUESDAY THROUGH FRIDAY NIGHT
231 AM CDT SAT OCT 27 2012
FOCUS FOR THE EARLY PORTION OF THE LONG TERM PERIOD IS THE DEEP
EASTERN U.S. UPPER TROUGH AND POST-TROPICAL SANDY INSIDE OF THE
TROUGH. 27.00Z ECMWF/GFS/CANADIAN/UKMET AND GFS ENSEMBLES ARE IN
VERY GOOD AGREEMENT THAT THE DEEP UPPER TROUGH WILL BE BLOCKED
BETWEEN RIDGING OVER THE WESTERN U.S....STRONG UPPER RIDGING NEAR
NEWFOUNDLAND AND PERHAPS EVEN RIDGING CONNECTING THESE TWO. AS
SUCH...THE MODELS TAKE AWHILE BEFORE LIFTING THE EASTERN TROUGH OUT.
IT MAY NOT BE UNTIL SOMETIME THURSDAY NIGHT OR FRIDAY BEFORE THE
EJECTION OCCURS. WITH THE EASTERN TROUGH BLOCKED FROM MOVING
MUCH...THE FORECAST AREA STAYS ON THE SUBSIDENT SIDE THROUGH AT
LEAST THURSDAY...MOSTLY PREVENTING PRECIPITATION. ONE CONCERN WOULD
BE DEFORMATION PRECIPITATION ASSOCIATED WITH POST-TROPICAL SANDY
RETROGRADING SLOWLY WESTWARD TOWARDS THE AREA TUESDAY INTO
WEDNESDAY. HOWEVER...MOST MODELS SUGGESTS THIS DEFORMATION BAND
WILL STAY EAST OF THE AREA...PERHAPS MAKING IT AS FAR WEST AS
EASTERN WISCONSIN. LOOKS LIKE WE WILL SEE A NORTHERLY BREEZE
INCREASE FOR TUESDAY AND PERHAPS WEDNESDAY TOO...PARTICULARLY
ACROSS WISCONSIN. FOR FRIDAY...GOOD MODEL CONSENSUS EXISTS FOR
SUBTROPICAL UPPER RIDGING TO CROSS THE CENTRAL AND SOUTHERN PLAINS
AHEAD OF A TROUGH CROSSING COLORADO. ANY WARM ADVECTION
PRECIPITATION ASSOCIATED WITH THE RIDGE LOOKS TO STAY TO THE SOUTH
AT THE PRESENT TIME...THOUGH AN INCREASE IN MID/HIGH CLOUDS SHOULD
OCCUR.
TEMPERATURES WILL GRADUALLY WARM THROUGH THE LONG TERM PERIOD...
ESPECIALLY TOWARDS THE END OF THE WEEK AS THE EASTERN UPPER TROUGH
LIFTS OUT. BY THURSDAY...READINGS SHOULD BE BACK TO NEAR NORMAL.
&&
.AVIATION...
1130 AM CDT SAT OCT 27 2012
UPPER LEVEL TROUGH WILL SLIDE ACROSS THE REGION
TONIGHT/SUNDAY...BRINGING SOME MID/HIGH LEVEL CLOUDINESS. LOWEST
CIGS PROBABLY 8-10 KFT...SO VFR CONDITIONS SHOULD PERSIST FOR THE
REST OF THE WEEKEND. DEEPER MOISTURE AND ANY SMALL PCPN CHANCES WILL
STAY NORTH OF THE TAF SITES. WITH HIGH PRESSURE PERSISTING AT THE
SFC...WIND FIELDS SHOULD BE RELATIVELY LIGHT...BECOMING MORE
SOUTHEAST/SOUTH LATE TONIGHT/SUNDAY.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
231 AM CDT SAT OCT 27 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM....AJ
AVIATION.....RIECK